Add the clang library to the repo (with some of my changes, too).

23 files changed, 13637 insertions, 0 deletions

diff --git a/clang/lib/Driver/Action.cpp b/clang/lib/Driver/Action.cpp
new file mode 100644
index 0000000..d7b4bc7
--- /dev/null
+++ b/clang/lib/Driver/Action.cpp
@@ -0,0 +1,122 @@
+//===--- Action.cpp - Abstract compilation steps --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Action.h"
+#include "llvm/Support/ErrorHandling.h"
+
+#include <cassert>
+using namespace clang::driver;
+
+Action::~Action() {
+  if (OwnsInputs) {
+    for (iterator it = begin(), ie = end(); it != ie; ++it)
+      delete *it;
+  }
+}
+
+const char *Action::getClassName(ActionClass AC) {
+  switch (AC) {
+  case InputClass: return "input";
+  case BindArchClass: return "bind-arch";
+  case PreprocessJobClass: return "preprocessor";
+  case PrecompileJobClass: return "precompiler";
+  case AnalyzeJobClass: return "analyzer";
+  case MigrateJobClass: return "migrator";
+  case CompileJobClass: return "compiler";
+  case AssembleJobClass: return "assembler";
+  case LinkJobClass: return "linker";
+  case LipoJobClass: return "lipo";
+  case DsymutilJobClass: return "dsymutil";
+  case VerifyJobClass: return "verify";
+  }
+
+  llvm_unreachable("invalid class");
+}
+
+void InputAction::anchor() {}
+
+InputAction::InputAction(const Arg &_Input, types::ID _Type)
+  : Action(InputClass, _Type), Input(_Input) {
+}
+
+void BindArchAction::anchor() {}
+
+BindArchAction::BindArchAction(Action *Input, const char *_ArchName)
+  : Action(BindArchClass, Input, Input->getType()), ArchName(_ArchName) {
+}
+
+void JobAction::anchor() {}
+
+JobAction::JobAction(ActionClass Kind, Action *Input, types::ID Type)
+  : Action(Kind, Input, Type) {
+}
+
+JobAction::JobAction(ActionClass Kind, const ActionList &Inputs, types::ID Type)
+  : Action(Kind, Inputs, Type) {
+}
+
+void PreprocessJobAction::anchor() {}
+
+PreprocessJobAction::PreprocessJobAction(Action *Input, types::ID OutputType)
+  : JobAction(PreprocessJobClass, Input, OutputType) {
+}
+
+void PrecompileJobAction::anchor() {}
+
+PrecompileJobAction::PrecompileJobAction(Action *Input, types::ID OutputType)
+  : JobAction(PrecompileJobClass, Input, OutputType) {
+}
+
+void AnalyzeJobAction::anchor() {}
+
+AnalyzeJobAction::AnalyzeJobAction(Action *Input, types::ID OutputType)
+  : JobAction(AnalyzeJobClass, Input, OutputType) {
+}
+
+void MigrateJobAction::anchor() {}
+
+MigrateJobAction::MigrateJobAction(Action *Input, types::ID OutputType)
+  : JobAction(MigrateJobClass, Input, OutputType) {
+}
+
+void CompileJobAction::anchor() {}
+
+CompileJobAction::CompileJobAction(Action *Input, types::ID OutputType)
+  : JobAction(CompileJobClass, Input, OutputType) {
+}
+
+void AssembleJobAction::anchor() {}
+
+AssembleJobAction::AssembleJobAction(Action *Input, types::ID OutputType)
+  : JobAction(AssembleJobClass, Input, OutputType) {
+}
+
+void LinkJobAction::anchor() {}
+
+LinkJobAction::LinkJobAction(ActionList &Inputs, types::ID Type)
+  : JobAction(LinkJobClass, Inputs, Type) {
+}
+
+void LipoJobAction::anchor() {}
+
+LipoJobAction::LipoJobAction(ActionList &Inputs, types::ID Type)
+  : JobAction(LipoJobClass, Inputs, Type) {
+}
+
+void DsymutilJobAction::anchor() {}
+
+DsymutilJobAction::DsymutilJobAction(ActionList &Inputs, types::ID Type)
+  : JobAction(DsymutilJobClass, Inputs, Type) {
+}
+
+void VerifyJobAction::anchor() {}
+
+VerifyJobAction::VerifyJobAction(ActionList &Inputs, types::ID Type)
+  : JobAction(VerifyJobClass, Inputs, Type) {
+}
diff --git a/clang/lib/Driver/Arg.cpp b/clang/lib/Driver/Arg.cpp
new file mode 100644
index 0000000..c0a2a50
--- /dev/null
+++ b/clang/lib/Driver/Arg.cpp
@@ -0,0 +1,121 @@
+//===--- Arg.cpp - Argument Implementations -------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Option.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang::driver;
+
+Arg::Arg(const Option *_Opt, unsigned _Index, const Arg *_BaseArg)
+  : Opt(_Opt), BaseArg(_BaseArg), Index(_Index),
+    Claimed(false), OwnsValues(false) {
+}
+
+Arg::Arg(const Option *_Opt, unsigned _Index, 
+         const char *Value0, const Arg *_BaseArg)
+  : Opt(_Opt), BaseArg(_BaseArg), Index(_Index),
+    Claimed(false), OwnsValues(false) {
+  Values.push_back(Value0);
+}
+
+Arg::Arg(const Option *_Opt, unsigned _Index, 
+         const char *Value0, const char *Value1, const Arg *_BaseArg)
+  : Opt(_Opt), BaseArg(_BaseArg), Index(_Index),
+    Claimed(false), OwnsValues(false) {
+  Values.push_back(Value0);
+  Values.push_back(Value1);
+}
+
+Arg::~Arg() {
+  if (OwnsValues) {
+    for (unsigned i = 0, e = Values.size(); i != e; ++i)
+      delete[] Values[i];
+  }
+}
+
+void Arg::dump() const {
+  llvm::errs() << "<";
+
+  llvm::errs() << " Opt:";
+  Opt->dump();
+
+  llvm::errs() << " Index:" << Index;
+
+  llvm::errs() << " Values: [";
+  for (unsigned i = 0, e = Values.size(); i != e; ++i) {
+    if (i) llvm::errs() << ", ";
+    llvm::errs() << "'" << Values[i] << "'";
+  }
+
+  llvm::errs() << "]>\n";
+}
+
+std::string Arg::getAsString(const ArgList &Args) const {
+  SmallString<256> Res;
+  llvm::raw_svector_ostream OS(Res);
+
+  ArgStringList ASL;
+  render(Args, ASL);
+  for (ArgStringList::iterator
+         it = ASL.begin(), ie = ASL.end(); it != ie; ++it) {
+    if (it != ASL.begin())
+      OS << ' ';
+    OS << *it;
+  }
+
+  return OS.str();
+}
+
+void Arg::renderAsInput(const ArgList &Args, ArgStringList &Output) const {
+  if (!getOption().hasNoOptAsInput()) {
+    render(Args, Output);
+    return;
+  }
+
+  for (unsigned i = 0, e = getNumValues(); i != e; ++i)
+    Output.push_back(getValue(Args, i));
+}
+
+void Arg::render(const ArgList &Args, ArgStringList &Output) const {
+  switch (getOption().getRenderStyle()) {
+  case Option::RenderValuesStyle:
+    for (unsigned i = 0, e = getNumValues(); i != e; ++i)
+      Output.push_back(getValue(Args, i));
+    break;
+
+  case Option::RenderCommaJoinedStyle: {
+    SmallString<256> Res;
+    llvm::raw_svector_ostream OS(Res);
+    OS << getOption().getName();
+    for (unsigned i = 0, e = getNumValues(); i != e; ++i) {
+      if (i) OS << ',';
+      OS << getValue(Args, i);
+    }
+    Output.push_back(Args.MakeArgString(OS.str()));
+    break;
+  }
+ 
+ case Option::RenderJoinedStyle:
+    Output.push_back(Args.GetOrMakeJoinedArgString(
+                       getIndex(), getOption().getName(), getValue(Args, 0)));
+    for (unsigned i = 1, e = getNumValues(); i != e; ++i)
+      Output.push_back(getValue(Args, i));
+    break;
+
+  case Option::RenderSeparateStyle:
+    Output.push_back(getOption().getName().data());
+    for (unsigned i = 0, e = getNumValues(); i != e; ++i)
+      Output.push_back(getValue(Args, i));
+    break;
+  }
+}
diff --git a/clang/lib/Driver/ArgList.cpp b/clang/lib/Driver/ArgList.cpp
new file mode 100644
index 0000000..55a0ddf
--- /dev/null
+++ b/clang/lib/Driver/ArgList.cpp
@@ -0,0 +1,333 @@
+//===--- ArgList.cpp - Argument List Management ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Option.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace clang::driver;
+
+void arg_iterator::SkipToNextArg() {
+  for (; Current != Args.end(); ++Current) {
+    // Done if there are no filters.
+    if (!Id0.isValid())
+      break;
+
+    // Otherwise require a match.
+    const Option &O = (*Current)->getOption();
+    if (O.matches(Id0) ||
+        (Id1.isValid() && O.matches(Id1)) ||
+        (Id2.isValid() && O.matches(Id2)))
+      break;
+  }
+}
+
+//
+
+ArgList::ArgList() {
+}
+
+ArgList::~ArgList() {
+}
+
+void ArgList::append(Arg *A) {
+  Args.push_back(A);
+}
+
+void ArgList::eraseArg(OptSpecifier Id) {
+  for (iterator it = begin(), ie = end(); it != ie; ) {
+    if ((*it)->getOption().matches(Id)) {
+      it = Args.erase(it);
+      ie = end();
+    } else {
+      ++it;
+    }
+  }
+}
+
+Arg *ArgList::getLastArgNoClaim(OptSpecifier Id) const {
+  // FIXME: Make search efficient?
+  for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it)
+    if ((*it)->getOption().matches(Id))
+      return *it;
+  return 0;
+}
+
+Arg *ArgList::getLastArg(OptSpecifier Id) const {
+  Arg *Res = 0;
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id)) {
+      Res = *it;
+      Res->claim();
+    }
+  }
+
+  return Res;
+}
+
+Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1) const {
+  Arg *Res = 0;
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id0) ||
+        (*it)->getOption().matches(Id1)) {
+      Res = *it;
+      Res->claim();
+
+    }
+  }
+
+  return Res;
+}
+
+Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
+                         OptSpecifier Id2) const {
+  Arg *Res = 0;
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id0) ||
+        (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2)) {
+      Res = *it;
+      Res->claim();
+    }
+  }
+
+  return Res;
+}
+
+Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
+                         OptSpecifier Id2, OptSpecifier Id3) const {
+  Arg *Res = 0;
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id0) ||
+        (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2) ||
+        (*it)->getOption().matches(Id3)) {
+      Res = *it;
+      Res->claim();
+    }
+  }
+
+  return Res;
+}
+
+Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
+                         OptSpecifier Id2, OptSpecifier Id3,
+                         OptSpecifier Id4) const {
+  Arg *Res = 0;
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id0) ||
+        (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2) ||
+        (*it)->getOption().matches(Id3) ||
+        (*it)->getOption().matches(Id4)) {
+      Res = *it;
+      Res->claim();
+    }
+  }
+
+  return Res;
+}
+
+bool ArgList::hasFlag(OptSpecifier Pos, OptSpecifier Neg, bool Default) const {
+  if (Arg *A = getLastArg(Pos, Neg))
+    return A->getOption().matches(Pos);
+  return Default;
+}
+
+StringRef ArgList::getLastArgValue(OptSpecifier Id,
+                                         StringRef Default) const {
+  if (Arg *A = getLastArg(Id))
+    return A->getValue(*this);
+  return Default;
+}
+
+int ArgList::getLastArgIntValue(OptSpecifier Id, int Default,
+                                clang::DiagnosticsEngine *Diags) const {
+  int Res = Default;
+
+  if (Arg *A = getLastArg(Id)) {
+    if (StringRef(A->getValue(*this)).getAsInteger(10, Res)) {
+      if (Diags)
+        Diags->Report(diag::err_drv_invalid_int_value)
+          << A->getAsString(*this) << A->getValue(*this);
+    }
+  }
+
+  return Res;
+}
+
+std::vector<std::string> ArgList::getAllArgValues(OptSpecifier Id) const {
+  SmallVector<const char *, 16> Values;
+  AddAllArgValues(Values, Id);
+  return std::vector<std::string>(Values.begin(), Values.end());
+}
+
+void ArgList::AddLastArg(ArgStringList &Output, OptSpecifier Id) const {
+  if (Arg *A = getLastArg(Id)) {
+    A->claim();
+    A->render(*this, Output);
+  }
+}
+
+void ArgList::AddAllArgs(ArgStringList &Output, OptSpecifier Id0,
+                         OptSpecifier Id1, OptSpecifier Id2) const {
+  for (arg_iterator it = filtered_begin(Id0, Id1, Id2),
+         ie = filtered_end(); it != ie; ++it) {
+    (*it)->claim();
+    (*it)->render(*this, Output);
+  }
+}
+
+void ArgList::AddAllArgValues(ArgStringList &Output, OptSpecifier Id0,
+                              OptSpecifier Id1, OptSpecifier Id2) const {
+  for (arg_iterator it = filtered_begin(Id0, Id1, Id2),
+         ie = filtered_end(); it != ie; ++it) {
+    (*it)->claim();
+    for (unsigned i = 0, e = (*it)->getNumValues(); i != e; ++i)
+      Output.push_back((*it)->getValue(*this, i));
+  }
+}
+
+void ArgList::AddAllArgsTranslated(ArgStringList &Output, OptSpecifier Id0,
+                                   const char *Translation,
+                                   bool Joined) const {
+  for (arg_iterator it = filtered_begin(Id0),
+         ie = filtered_end(); it != ie; ++it) {
+    (*it)->claim();
+
+    if (Joined) {
+      Output.push_back(MakeArgString(StringRef(Translation) +
+                                     (*it)->getValue(*this, 0)));
+    } else {
+      Output.push_back(Translation);
+      Output.push_back((*it)->getValue(*this, 0));
+    }
+  }
+}
+
+void ArgList::ClaimAllArgs(OptSpecifier Id0) const {
+  for (arg_iterator it = filtered_begin(Id0),
+         ie = filtered_end(); it != ie; ++it)
+    (*it)->claim();
+}
+
+void ArgList::ClaimAllArgs() const {
+  for (const_iterator it = begin(), ie = end(); it != ie; ++it)
+    if (!(*it)->isClaimed())
+      (*it)->claim();
+}
+
+const char *ArgList::MakeArgString(const Twine &T) const {
+  SmallString<256> Str;
+  T.toVector(Str);
+  return MakeArgString(Str.str());
+}
+
+const char *ArgList::GetOrMakeJoinedArgString(unsigned Index,
+                                              StringRef LHS,
+                                              StringRef RHS) const {
+  StringRef Cur = getArgString(Index);
+  if (Cur.size() == LHS.size() + RHS.size() &&
+      Cur.startswith(LHS) && Cur.endswith(RHS))
+    return Cur.data();
+
+  return MakeArgString(LHS + RHS);
+}
+
+//
+
+InputArgList::InputArgList(const char* const *ArgBegin,
+                           const char* const *ArgEnd)
+  : NumInputArgStrings(ArgEnd - ArgBegin) {
+  ArgStrings.append(ArgBegin, ArgEnd);
+}
+
+InputArgList::~InputArgList() {
+  // An InputArgList always owns its arguments.
+  for (iterator it = begin(), ie = end(); it != ie; ++it)
+    delete *it;
+}
+
+unsigned InputArgList::MakeIndex(StringRef String0) const {
+  unsigned Index = ArgStrings.size();
+
+  // Tuck away so we have a reliable const char *.
+  SynthesizedStrings.push_back(String0);
+  ArgStrings.push_back(SynthesizedStrings.back().c_str());
+
+  return Index;
+}
+
+unsigned InputArgList::MakeIndex(StringRef String0,
+                                 StringRef String1) const {
+  unsigned Index0 = MakeIndex(String0);
+  unsigned Index1 = MakeIndex(String1);
+  assert(Index0 + 1 == Index1 && "Unexpected non-consecutive indices!");
+  (void) Index1;
+  return Index0;
+}
+
+const char *InputArgList::MakeArgString(StringRef Str) const {
+  return getArgString(MakeIndex(Str));
+}
+
+//
+
+DerivedArgList::DerivedArgList(const InputArgList &_BaseArgs)
+  : BaseArgs(_BaseArgs) {
+}
+
+DerivedArgList::~DerivedArgList() {
+  // We only own the arguments we explicitly synthesized.
+  for (iterator it = SynthesizedArgs.begin(), ie = SynthesizedArgs.end();
+       it != ie; ++it)
+    delete *it;
+}
+
+const char *DerivedArgList::MakeArgString(StringRef Str) const {
+  return BaseArgs.MakeArgString(Str);
+}
+
+Arg *DerivedArgList::MakeFlagArg(const Arg *BaseArg, const Option *Opt) const {
+  Arg *A = new Arg(Opt, BaseArgs.MakeIndex(Opt->getName()), BaseArg);
+  SynthesizedArgs.push_back(A);
+  return A;
+}
+
+Arg *DerivedArgList::MakePositionalArg(const Arg *BaseArg, const Option *Opt,
+                                       StringRef Value) const {
+  unsigned Index = BaseArgs.MakeIndex(Value);
+  Arg *A = new Arg(Opt, Index, BaseArgs.getArgString(Index), BaseArg);
+  SynthesizedArgs.push_back(A);
+  return A;
+}
+
+Arg *DerivedArgList::MakeSeparateArg(const Arg *BaseArg, const Option *Opt,
+                                     StringRef Value) const {
+  unsigned Index = BaseArgs.MakeIndex(Opt->getName(), Value);
+  Arg *A = new Arg(Opt, Index, BaseArgs.getArgString(Index + 1), BaseArg);
+  SynthesizedArgs.push_back(A);
+  return A;
+}
+
+Arg *DerivedArgList::MakeJoinedArg(const Arg *BaseArg, const Option *Opt,
+                                   StringRef Value) const {
+  unsigned Index = BaseArgs.MakeIndex(Opt->getName().str() + Value.str());
+  Arg *A = new Arg(Opt, Index,
+                   BaseArgs.getArgString(Index) + Opt->getName().size(),
+                   BaseArg);
+  SynthesizedArgs.push_back(A);
+  return A;
+}
diff --git a/clang/lib/Driver/CC1AsOptions.cpp b/clang/lib/Driver/CC1AsOptions.cpp
new file mode 100644
index 0000000..ea80f5a
--- /dev/null
+++ b/clang/lib/Driver/CC1AsOptions.cpp
@@ -0,0 +1,39 @@
+//===--- CC1AsOptions.cpp - Clang Assembler Options Table -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/CC1AsOptions.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/OptTable.h"
+using namespace clang;
+using namespace clang::driver;
+using namespace clang::driver::options;
+using namespace clang::driver::cc1asoptions;
+
+static const OptTable::Info CC1AsInfoTable[] = {
+#define OPTION(NAME, ID, KIND, GROUP, ALIAS, FLAGS, PARAM, \
+               HELPTEXT, METAVAR)   \
+  { NAME, HELPTEXT, METAVAR, Option::KIND##Class, PARAM, FLAGS, \
+    OPT_##GROUP, OPT_##ALIAS },
+#include "clang/Driver/CC1AsOptions.inc"
+};
+
+namespace {
+
+class CC1AsOptTable : public OptTable {
+public:
+  CC1AsOptTable()
+    : OptTable(CC1AsInfoTable,
+               sizeof(CC1AsInfoTable) / sizeof(CC1AsInfoTable[0])) {}
+};
+
+}
+
+OptTable *clang::driver::createCC1AsOptTable() {
+  return new CC1AsOptTable();
+}
diff --git a/clang/lib/Driver/CC1Options.cpp b/clang/lib/Driver/CC1Options.cpp
new file mode 100644
index 0000000..884b363
--- /dev/null
+++ b/clang/lib/Driver/CC1Options.cpp
@@ -0,0 +1,38 @@
+//===--- CC1Options.cpp - Clang CC1 Options Table -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/CC1Options.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/OptTable.h"
+using namespace clang;
+using namespace clang::driver;
+using namespace clang::driver::options;
+using namespace clang::driver::cc1options;
+
+static const OptTable::Info CC1InfoTable[] = {
+#define OPTION(NAME, ID, KIND, GROUP, ALIAS, FLAGS, PARAM, \
+               HELPTEXT, METAVAR)   \
+  { NAME, HELPTEXT, METAVAR, Option::KIND##Class, PARAM, FLAGS, \
+    OPT_##GROUP, OPT_##ALIAS },
+#include "clang/Driver/CC1Options.inc"
+};
+
+namespace {
+
+class CC1OptTable : public OptTable {
+public:
+  CC1OptTable()
+    : OptTable(CC1InfoTable, sizeof(CC1InfoTable) / sizeof(CC1InfoTable[0])) {}
+};
+
+}
+
+OptTable *clang::driver::createCC1OptTable() {
+  return new CC1OptTable();
+}
diff --git a/clang/lib/Driver/CMakeLists.txt b/clang/lib/Driver/CMakeLists.txt
new file mode 100644
index 0000000..a798e20
--- /dev/null
+++ b/clang/lib/Driver/CMakeLists.txt
@@ -0,0 +1,33 @@
+set(LLVM_USED_LIBS clangBasic clangAST clangParse)
+
+add_clang_library(clangDriver
+  Action.cpp
+  Arg.cpp
+  ArgList.cpp
+  CC1Options.cpp
+  CC1AsOptions.cpp
+  Compilation.cpp
+  Driver.cpp
+  DriverOptions.cpp
+  Job.cpp
+  Option.cpp
+  OptTable.cpp
+  Phases.cpp
+  Tool.cpp
+  ToolChain.cpp
+  ToolChains.cpp
+  WindowsToolChain.cpp
+  Tools.cpp
+  Types.cpp
+  )
+
+IF(MSVC)
+  get_target_property(NON_ANSI_COMPILE_FLAGS clangDriver COMPILE_FLAGS)
+  string(REPLACE /Za
+    "" NON_ANSI_COMPILE_FLAGS
+    ${NON_ANSI_COMPILE_FLAGS})
+  set_target_properties(clangDriver PROPERTIES COMPILE_FLAGS ${NON_ANSI_COMPILE_FLAGS})
+ENDIF(MSVC)
+
+add_dependencies(clangDriver ClangAttrList ClangDiagnosticDriver
+                 ClangDriverOptions ClangCC1Options ClangCC1AsOptions)
diff --git a/clang/lib/Driver/Compilation.cpp b/clang/lib/Driver/Compilation.cpp
new file mode 100644
index 0000000..5553fc9
--- /dev/null
+++ b/clang/lib/Driver/Compilation.cpp
@@ -0,0 +1,236 @@
+//===--- Compilation.cpp - Compilation Task Implementation ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Compilation.h"
+
+#include "clang/Driver/Action.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/ToolChain.h"
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Program.h"
+#include <sys/stat.h>
+#include <errno.h>
+
+using namespace clang::driver;
+using namespace clang;
+
+Compilation::Compilation(const Driver &D, const ToolChain &_DefaultToolChain,
+                         InputArgList *_Args, DerivedArgList *_TranslatedArgs)
+  : TheDriver(D), DefaultToolChain(_DefaultToolChain), Args(_Args),
+    TranslatedArgs(_TranslatedArgs), Redirects(0) {
+}
+
+Compilation::~Compilation() {
+  delete TranslatedArgs;
+  delete Args;
+
+  // Free any derived arg lists.
+  for (llvm::DenseMap<std::pair<const ToolChain*, const char*>,
+                      DerivedArgList*>::iterator it = TCArgs.begin(),
+         ie = TCArgs.end(); it != ie; ++it)
+    if (it->second != TranslatedArgs)
+      delete it->second;
+
+  // Free the actions, if built.
+  for (ActionList::iterator it = Actions.begin(), ie = Actions.end();
+       it != ie; ++it)
+    delete *it;
+
+  // Free redirections of stdout/stderr.
+  if (Redirects) {
+    delete Redirects[1];
+    delete Redirects[2];
+    delete [] Redirects;
+  }
+}
+
+const DerivedArgList &Compilation::getArgsForToolChain(const ToolChain *TC,
+                                                       const char *BoundArch) {
+  if (!TC)
+    TC = &DefaultToolChain;
+
+  DerivedArgList *&Entry = TCArgs[std::make_pair(TC, BoundArch)];
+  if (!Entry) {
+    Entry = TC->TranslateArgs(*TranslatedArgs, BoundArch);
+    if (!Entry)
+      Entry = TranslatedArgs;
+  }
+
+  return *Entry;
+}
+
+void Compilation::PrintJob(raw_ostream &OS, const Job &J,
+                           const char *Terminator, bool Quote) const {
+  if (const Command *C = dyn_cast<Command>(&J)) {
+    OS << " \"" << C->getExecutable() << '"';
+    for (ArgStringList::const_iterator it = C->getArguments().begin(),
+           ie = C->getArguments().end(); it != ie; ++it) {
+      OS << ' ';
+      if (!Quote && !std::strpbrk(*it, " \"\\$")) {
+        OS << *it;
+        continue;
+      }
+
+      // Quote the argument and escape shell special characters; this isn't
+      // really complete but is good enough.
+      OS << '"';
+      for (const char *s = *it; *s; ++s) {
+        if (*s == '"' || *s == '\\' || *s == '$')
+          OS << '\\';
+        OS << *s;
+      }
+      OS << '"';
+    }
+    OS << Terminator;
+  } else {
+    const JobList *Jobs = cast<JobList>(&J);
+    for (JobList::const_iterator
+           it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
+      PrintJob(OS, **it, Terminator, Quote);
+  }
+}
+
+bool Compilation::CleanupFileList(const ArgStringList &Files,
+                                  bool IssueErrors) const {
+  bool Success = true;
+
+  for (ArgStringList::const_iterator
+         it = Files.begin(), ie = Files.end(); it != ie; ++it) {
+
+    llvm::sys::Path P(*it);
+    std::string Error;
+
+    // Don't try to remove files which we don't have write access to (but may be
+    // able to remove). Underlying tools may have intentionally not overwritten
+    // them.
+    if (!P.canWrite())
+      continue;
+
+    if (P.eraseFromDisk(false, &Error)) {
+      // Failure is only failure if the file exists and is "regular". There is
+      // a race condition here due to the limited interface of
+      // llvm::sys::Path, we want to know if the removal gave ENOENT.
+
+      // FIXME: Grumble, P.exists() is broken. PR3837.
+      struct stat buf;
+      if (::stat(P.c_str(), &buf) == 0 ? (buf.st_mode & S_IFMT) == S_IFREG :
+                                         (errno != ENOENT)) {
+        if (IssueErrors)
+          getDriver().Diag(clang::diag::err_drv_unable_to_remove_file)
+            << Error;
+        Success = false;
+      }
+    }
+  }
+
+  return Success;
+}
+
+int Compilation::ExecuteCommand(const Command &C,
+                                const Command *&FailingCommand) const {
+  llvm::sys::Path Prog(C.getExecutable());
+  const char **Argv = new const char*[C.getArguments().size() + 2];
+  Argv[0] = C.getExecutable();
+  std::copy(C.getArguments().begin(), C.getArguments().end(), Argv+1);
+  Argv[C.getArguments().size() + 1] = 0;
+
+  if ((getDriver().CCCEcho || getDriver().CCPrintOptions ||
+       getArgs().hasArg(options::OPT_v)) && !getDriver().CCGenDiagnostics) {
+    raw_ostream *OS = &llvm::errs();
+
+    // Follow gcc implementation of CC_PRINT_OPTIONS; we could also cache the
+    // output stream.
+    if (getDriver().CCPrintOptions && getDriver().CCPrintOptionsFilename) {
+      std::string Error;
+      OS = new llvm::raw_fd_ostream(getDriver().CCPrintOptionsFilename,
+                                    Error,
+                                    llvm::raw_fd_ostream::F_Append);
+      if (!Error.empty()) {
+        getDriver().Diag(clang::diag::err_drv_cc_print_options_failure)
+          << Error;
+        FailingCommand = &C;
+        delete OS;
+        return 1;
+      }
+    }
+
+    if (getDriver().CCPrintOptions)
+      *OS << "[Logging clang options]";
+
+    PrintJob(*OS, C, "\n", /*Quote=*/getDriver().CCPrintOptions);
+
+    if (OS != &llvm::errs())
+      delete OS;
+  }
+
+  std::string Error;
+  int Res =
+    llvm::sys::Program::ExecuteAndWait(Prog, Argv,
+                                       /*env*/0, Redirects,
+                                       /*secondsToWait*/0, /*memoryLimit*/0,
+                                       &Error);
+  if (!Error.empty()) {
+    assert(Res && "Error string set with 0 result code!");
+    getDriver().Diag(clang::diag::err_drv_command_failure) << Error;
+  }
+
+  if (Res)
+    FailingCommand = &C;
+
+  delete[] Argv;
+  return Res;
+}
+
+int Compilation::ExecuteJob(const Job &J,
+                            const Command *&FailingCommand) const {
+  if (const Command *C = dyn_cast<Command>(&J)) {
+    return ExecuteCommand(*C, FailingCommand);
+  } else {
+    const JobList *Jobs = cast<JobList>(&J);
+    for (JobList::const_iterator
+           it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
+      if (int Res = ExecuteJob(**it, FailingCommand))
+        return Res;
+    return 0;
+  }
+}
+
+void Compilation::initCompilationForDiagnostics(void) {
+  // Free actions and jobs.
+  DeleteContainerPointers(Actions);
+  Jobs.clear();
+
+  // Clear temporary/results file lists.
+  TempFiles.clear();
+  ResultFiles.clear();
+
+  // Remove any user specified output.  Claim any unclaimed arguments, so as
+  // to avoid emitting warnings about unused args.
+  OptSpecifier OutputOpts[] = { options::OPT_o, options::OPT_MD,
+                                options::OPT_MMD };
+  for (unsigned i = 0; i != sizeof(OutputOpts)/sizeof(OutputOpts[0]); ++i) {
+    if (TranslatedArgs->hasArg(OutputOpts[i]))
+      TranslatedArgs->eraseArg(OutputOpts[i]);
+  }
+  TranslatedArgs->ClaimAllArgs();
+
+  // Redirect stdout/stderr to /dev/null.
+  Redirects = new const llvm::sys::Path*[3]();
+  Redirects[1] = new const llvm::sys::Path();
+  Redirects[2] = new const llvm::sys::Path();
+}
+
+StringRef Compilation::getSysRoot(void) const {
+  return getDriver().SysRoot;
+}
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
new file mode 100644
index 0000000..3ddac69
--- /dev/null
+++ b/clang/lib/Driver/Driver.cpp
@@ -0,0 +1,1789 @@
+//===--- Driver.cpp - Clang GCC Compatible Driver -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Driver.h"
+
+#include "clang/Driver/Action.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Job.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+#include "clang/Basic/Version.h"
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
+
+#include "InputInfo.h"
+#include "ToolChains.h"
+
+#include <map>
+
+#include "clang/Config/config.h"
+
+using namespace clang::driver;
+using namespace clang;
+
+Driver::Driver(StringRef ClangExecutable,
+               StringRef DefaultTargetTriple,
+               StringRef DefaultImageName,
+               bool IsProduction,
+               DiagnosticsEngine &Diags)
+  : Opts(createDriverOptTable()), Diags(Diags),
+    ClangExecutable(ClangExecutable), SysRoot(DEFAULT_SYSROOT),
+    UseStdLib(true), DefaultTargetTriple(DefaultTargetTriple),
+    DefaultImageName(DefaultImageName),
+    DriverTitle("clang \"gcc-compatible\" driver"),
+    CCPrintOptionsFilename(0), CCPrintHeadersFilename(0),
+    CCLogDiagnosticsFilename(0), CCCIsCXX(false),
+    CCCIsCPP(false),CCCEcho(false), CCCPrintBindings(false),
+    CCPrintOptions(false), CCPrintHeaders(false), CCLogDiagnostics(false),
+    CCGenDiagnostics(false), CCCGenericGCCName(""), CheckInputsExist(true),
+    CCCUseClang(true), CCCUseClangCXX(true), CCCUseClangCPP(true),
+    CCCUsePCH(true), SuppressMissingInputWarning(false) {
+  if (IsProduction) {
+    // In a "production" build, only use clang on architectures we expect to
+    // work.
+    //
+    // During development its more convenient to always have the driver use
+    // clang, but we don't want users to be confused when things don't work, or
+    // to file bugs for things we don't support.
+    CCCClangArchs.insert(llvm::Triple::x86);
+    CCCClangArchs.insert(llvm::Triple::x86_64);
+    CCCClangArchs.insert(llvm::Triple::arm);
+  }
+
+  Name = llvm::sys::path::stem(ClangExecutable);
+  Dir  = llvm::sys::path::parent_path(ClangExecutable);
+
+  // Compute the path to the resource directory.
+  StringRef ClangResourceDir(CLANG_RESOURCE_DIR);
+  SmallString<128> P(Dir);
+  if (ClangResourceDir != "")
+    llvm::sys::path::append(P, ClangResourceDir);
+  else
+    llvm::sys::path::append(P, "..", "lib", "clang", CLANG_VERSION_STRING);
+  ResourceDir = P.str();
+}
+
+Driver::~Driver() {
+  delete Opts;
+
+  for (llvm::StringMap<ToolChain *>::iterator I = ToolChains.begin(),
+                                              E = ToolChains.end();
+       I != E; ++I)
+    delete I->second;
+}
+
+InputArgList *Driver::ParseArgStrings(ArrayRef<const char *> ArgList) {
+  llvm::PrettyStackTraceString CrashInfo("Command line argument parsing");
+  unsigned MissingArgIndex, MissingArgCount;
+  InputArgList *Args = getOpts().ParseArgs(ArgList.begin(), ArgList.end(),
+                                           MissingArgIndex, MissingArgCount);
+
+  // Check for missing argument error.
+  if (MissingArgCount)
+    Diag(clang::diag::err_drv_missing_argument)
+      << Args->getArgString(MissingArgIndex) << MissingArgCount;
+
+  // Check for unsupported options.
+  for (ArgList::const_iterator it = Args->begin(), ie = Args->end();
+       it != ie; ++it) {
+    Arg *A = *it;
+    if (A->getOption().isUnsupported()) {
+      Diag(clang::diag::err_drv_unsupported_opt) << A->getAsString(*Args);
+      continue;
+    }
+
+    // Warn about -mcpu= without an argument.
+    if (A->getOption().matches(options::OPT_mcpu_EQ) && 
+        A->containsValue("")) {
+      Diag(clang::diag::warn_drv_empty_joined_argument) << A->getAsString(*Args);
+    }
+  }
+
+  return Args;
+}
+
+// Determine which compilation mode we are in. We look for options which
+// affect the phase, starting with the earliest phases, and record which
+// option we used to determine the final phase.
+phases::ID Driver::getFinalPhase(const DerivedArgList &DAL, Arg **FinalPhaseArg)
+const {
+  Arg *PhaseArg = 0;
+  phases::ID FinalPhase;
+
+  // -{E,M,MM} only run the preprocessor.
+  if (CCCIsCPP ||
+      (PhaseArg = DAL.getLastArg(options::OPT_E)) ||
+      (PhaseArg = DAL.getLastArg(options::OPT_M, options::OPT_MM))) {
+    FinalPhase = phases::Preprocess;
+
+    // -{fsyntax-only,-analyze,emit-ast,S} only run up to the compiler.
+  } else if ((PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_rewrite_objc)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_rewrite_legacy_objc)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT__migrate)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT__analyze,
+                                        options::OPT__analyze_auto)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_emit_ast)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_S))) {
+    FinalPhase = phases::Compile;
+
+    // -c only runs up to the assembler.
+  } else if ((PhaseArg = DAL.getLastArg(options::OPT_c))) {
+    FinalPhase = phases::Assemble;
+
+    // Otherwise do everything.
+  } else
+    FinalPhase = phases::Link;
+
+  if (FinalPhaseArg)
+    *FinalPhaseArg = PhaseArg;
+
+  return FinalPhase;
+}
+
+DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
+  DerivedArgList *DAL = new DerivedArgList(Args);
+
+  bool HasNostdlib = Args.hasArg(options::OPT_nostdlib);
+  for (ArgList::const_iterator it = Args.begin(),
+         ie = Args.end(); it != ie; ++it) {
+    const Arg *A = *it;
+
+    // Unfortunately, we have to parse some forwarding options (-Xassembler,
+    // -Xlinker, -Xpreprocessor) because we either integrate their functionality
+    // (assembler and preprocessor), or bypass a previous driver ('collect2').
+
+    // Rewrite linker options, to replace --no-demangle with a custom internal
+    // option.
+    if ((A->getOption().matches(options::OPT_Wl_COMMA) ||
+         A->getOption().matches(options::OPT_Xlinker)) &&
+        A->containsValue("--no-demangle")) {
+      // Add the rewritten no-demangle argument.
+      DAL->AddFlagArg(A, Opts->getOption(options::OPT_Z_Xlinker__no_demangle));
+
+      // Add the remaining values as Xlinker arguments.
+      for (unsigned i = 0, e = A->getNumValues(); i != e; ++i)
+        if (StringRef(A->getValue(Args, i)) != "--no-demangle")
+          DAL->AddSeparateArg(A, Opts->getOption(options::OPT_Xlinker),
+                              A->getValue(Args, i));
+
+      continue;
+    }
+
+    // Rewrite preprocessor options, to replace -Wp,-MD,FOO which is used by
+    // some build systems. We don't try to be complete here because we don't
+    // care to encourage this usage model.
+    if (A->getOption().matches(options::OPT_Wp_COMMA) &&
+        A->getNumValues() == 2 &&
+        (A->getValue(Args, 0) == StringRef("-MD") ||
+         A->getValue(Args, 0) == StringRef("-MMD"))) {
+      // Rewrite to -MD/-MMD along with -MF.
+      if (A->getValue(Args, 0) == StringRef("-MD"))
+        DAL->AddFlagArg(A, Opts->getOption(options::OPT_MD));
+      else
+        DAL->AddFlagArg(A, Opts->getOption(options::OPT_MMD));
+      DAL->AddSeparateArg(A, Opts->getOption(options::OPT_MF),
+                          A->getValue(Args, 1));
+      continue;
+    }
+
+    // Rewrite reserved library names.
+    if (A->getOption().matches(options::OPT_l)) {
+      StringRef Value = A->getValue(Args);
+
+      // Rewrite unless -nostdlib is present.
+      if (!HasNostdlib && Value == "stdc++") {
+        DAL->AddFlagArg(A, Opts->getOption(
+                              options::OPT_Z_reserved_lib_stdcxx));
+        continue;
+      }
+
+      // Rewrite unconditionally.
+      if (Value == "cc_kext") {
+        DAL->AddFlagArg(A, Opts->getOption(
+                              options::OPT_Z_reserved_lib_cckext));
+        continue;
+      }
+    }
+
+    DAL->append(*it);
+  }
+
+  // Add a default value of -mlinker-version=, if one was given and the user
+  // didn't specify one.
+#if defined(HOST_LINK_VERSION)
+  if (!Args.hasArg(options::OPT_mlinker_version_EQ)) {
+    DAL->AddJoinedArg(0, Opts->getOption(options::OPT_mlinker_version_EQ),
+                      HOST_LINK_VERSION);
+    DAL->getLastArg(options::OPT_mlinker_version_EQ)->claim();
+  }
+#endif
+
+  return DAL;
+}
+
+Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
+  llvm::PrettyStackTraceString CrashInfo("Compilation construction");
+
+  // FIXME: Handle environment options which affect driver behavior, somewhere
+  // (client?). GCC_EXEC_PREFIX, LPATH, CC_PRINT_OPTIONS.
+
+  if (char *env = ::getenv("COMPILER_PATH")) {
+    StringRef CompilerPath = env;
+    while (!CompilerPath.empty()) {
+      std::pair<StringRef, StringRef> Split = CompilerPath.split(':');      
+      PrefixDirs.push_back(Split.first);
+      CompilerPath = Split.second;
+    }
+  }
+
+  // FIXME: What are we going to do with -V and -b?
+
+  // FIXME: This stuff needs to go into the Compilation, not the driver.
+  bool CCCPrintOptions = false, CCCPrintActions = false;
+
+  InputArgList *Args = ParseArgStrings(ArgList.slice(1));
+
+  // -no-canonical-prefixes is used very early in main.
+  Args->ClaimAllArgs(options::OPT_no_canonical_prefixes);
+
+  // Ignore -pipe.
+  Args->ClaimAllArgs(options::OPT_pipe);
+
+  // Extract -ccc args.
+  //
+  // FIXME: We need to figure out where this behavior should live. Most of it
+  // should be outside in the client; the parts that aren't should have proper
+  // options, either by introducing new ones or by overloading gcc ones like -V
+  // or -b.
+  CCCPrintOptions = Args->hasArg(options::OPT_ccc_print_options);
+  CCCPrintActions = Args->hasArg(options::OPT_ccc_print_phases);
+  CCCPrintBindings = Args->hasArg(options::OPT_ccc_print_bindings);
+  CCCIsCXX = Args->hasArg(options::OPT_ccc_cxx) || CCCIsCXX;
+  CCCEcho = Args->hasArg(options::OPT_ccc_echo);
+  if (const Arg *A = Args->getLastArg(options::OPT_ccc_gcc_name))
+    CCCGenericGCCName = A->getValue(*Args);
+  CCCUseClangCXX = Args->hasFlag(options::OPT_ccc_clang_cxx,
+                                 options::OPT_ccc_no_clang_cxx,
+                                 CCCUseClangCXX);
+  CCCUsePCH = Args->hasFlag(options::OPT_ccc_pch_is_pch,
+                            options::OPT_ccc_pch_is_pth);
+  CCCUseClang = !Args->hasArg(options::OPT_ccc_no_clang);
+  CCCUseClangCPP = !Args->hasArg(options::OPT_ccc_no_clang_cpp);
+  if (const Arg *A = Args->getLastArg(options::OPT_ccc_clang_archs)) {
+    StringRef Cur = A->getValue(*Args);
+
+    CCCClangArchs.clear();
+    while (!Cur.empty()) {
+      std::pair<StringRef, StringRef> Split = Cur.split(',');
+
+      if (!Split.first.empty()) {
+        llvm::Triple::ArchType Arch =
+          llvm::Triple(Split.first, "", "").getArch();
+
+        if (Arch == llvm::Triple::UnknownArch)
+          Diag(clang::diag::err_drv_invalid_arch_name) << Split.first;
+
+        CCCClangArchs.insert(Arch);
+      }
+
+      Cur = Split.second;
+    }
+  }
+  // FIXME: DefaultTargetTriple is used by the target-prefixed calls to as/ld
+  // and getToolChain is const.
+  if (const Arg *A = Args->getLastArg(options::OPT_target))
+    DefaultTargetTriple = A->getValue(*Args);
+  if (const Arg *A = Args->getLastArg(options::OPT_ccc_install_dir))
+    Dir = InstalledDir = A->getValue(*Args);
+  for (arg_iterator it = Args->filtered_begin(options::OPT_B),
+         ie = Args->filtered_end(); it != ie; ++it) {
+    const Arg *A = *it;
+    A->claim();
+    PrefixDirs.push_back(A->getValue(*Args, 0));
+  }
+  if (const Arg *A = Args->getLastArg(options::OPT__sysroot_EQ))
+    SysRoot = A->getValue(*Args);
+  if (Args->hasArg(options::OPT_nostdlib))
+    UseStdLib = false;
+
+  // Perform the default argument translations.
+  DerivedArgList *TranslatedArgs = TranslateInputArgs(*Args);
+
+  // Owned by the host.
+  const ToolChain &TC = getToolChain(*Args);
+
+  // The compilation takes ownership of Args.
+  Compilation *C = new Compilation(*this, TC, Args, TranslatedArgs);
+
+  // FIXME: This behavior shouldn't be here.
+  if (CCCPrintOptions) {
+    PrintOptions(C->getInputArgs());
+    return C;
+  }
+
+  if (!HandleImmediateArgs(*C))
+    return C;
+
+  // Construct the list of inputs.
+  InputList Inputs;
+  BuildInputs(C->getDefaultToolChain(), C->getArgs(), Inputs);
+
+  // Construct the list of abstract actions to perform for this compilation. On
+  // Darwin target OSes this uses the driver-driver and universal actions.
+  if (TC.getTriple().isOSDarwin())
+    BuildUniversalActions(C->getDefaultToolChain(), C->getArgs(),
+                          Inputs, C->getActions());
+  else
+    BuildActions(C->getDefaultToolChain(), C->getArgs(), Inputs,
+                 C->getActions());
+
+  if (CCCPrintActions) {
+    PrintActions(*C);
+    return C;
+  }
+
+  BuildJobs(*C);
+
+  return C;
+}
+
+// When clang crashes, produce diagnostic information including the fully
+// preprocessed source file(s).  Request that the developer attach the
+// diagnostic information to a bug report.
+void Driver::generateCompilationDiagnostics(Compilation &C,
+                                            const Command *FailingCommand) {
+  if (C.getArgs().hasArg(options::OPT_fno_crash_diagnostics))
+    return;  
+
+  // Don't try to generate diagnostics for link jobs.
+  if (FailingCommand->getCreator().isLinkJob())
+    return;
+
+  Diag(clang::diag::note_drv_command_failed_diag_msg)
+    << "Please submit a bug report to " BUG_REPORT_URL " and include command"
+    " line arguments and all diagnostic information.";
+
+  // Suppress driver output and emit preprocessor output to temp file.
+  CCCIsCPP = true;
+  CCGenDiagnostics = true;
+
+  // Save the original job command(s).
+  std::string Cmd;
+  llvm::raw_string_ostream OS(Cmd);
+  C.PrintJob(OS, C.getJobs(), "\n", false);
+  OS.flush();
+
+  // Clear stale state and suppress tool output.
+  C.initCompilationForDiagnostics();
+  Diags.Reset();
+
+  // Construct the list of inputs.
+  InputList Inputs;
+  BuildInputs(C.getDefaultToolChain(), C.getArgs(), Inputs);
+
+  for (InputList::iterator it = Inputs.begin(), ie = Inputs.end(); it != ie;) {
+    bool IgnoreInput = false;
+
+    // Ignore input from stdin or any inputs that cannot be preprocessed.
+    if (!strcmp(it->second->getValue(C.getArgs()), "-")) {
+      Diag(clang::diag::note_drv_command_failed_diag_msg)
+        << "Error generating preprocessed source(s) - ignoring input from stdin"
+        ".";
+      IgnoreInput = true;
+    } else if (types::getPreprocessedType(it->first) == types::TY_INVALID) {
+      IgnoreInput = true;
+    }
+
+    if (IgnoreInput) {
+      it = Inputs.erase(it);
+      ie = Inputs.end();
+    } else {
+      ++it;
+    }
+  }
+
+  // Don't attempt to generate preprocessed files if multiple -arch options are
+  // used, unless they're all duplicates.
+  llvm::StringSet<> ArchNames;
+  for (ArgList::const_iterator it = C.getArgs().begin(), ie = C.getArgs().end();
+       it != ie; ++it) {
+    Arg *A = *it;
+    if (A->getOption().matches(options::OPT_arch)) {
+      StringRef ArchName = A->getValue(C.getArgs());
+      ArchNames.insert(ArchName);
+    }
+  }
+  if (ArchNames.size() > 1) {
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+      << "Error generating preprocessed source(s) - cannot generate "
+      "preprocessed source with multiple -arch options.";
+    return;
+  }
+
+  if (Inputs.empty()) {
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+      << "Error generating preprocessed source(s) - no preprocessable inputs.";
+    return;
+  }
+
+  // Construct the list of abstract actions to perform for this compilation. On
+  // Darwin OSes this uses the driver-driver and builds universal actions.
+  const ToolChain &TC = C.getDefaultToolChain();
+  if (TC.getTriple().isOSDarwin())
+    BuildUniversalActions(TC, C.getArgs(), Inputs, C.getActions());
+  else
+    BuildActions(TC, C.getArgs(), Inputs, C.getActions());
+
+  BuildJobs(C);
+
+  // If there were errors building the compilation, quit now.
+  if (Diags.hasErrorOccurred()) {
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+      << "Error generating preprocessed source(s).";
+    return;
+  }
+
+  // Generate preprocessed output.
+  FailingCommand = 0;
+  int Res = C.ExecuteJob(C.getJobs(), FailingCommand);
+
+  // If the command succeeded, we are done.
+  if (Res == 0) {
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+      << "Preprocessed source(s) and associated run script(s) are located at:";
+    ArgStringList Files = C.getTempFiles();
+    for (ArgStringList::const_iterator it = Files.begin(), ie = Files.end();
+         it != ie; ++it) {
+      Diag(clang::diag::note_drv_command_failed_diag_msg) << *it;
+
+      std::string Err;
+      std::string Script = StringRef(*it).rsplit('.').first;
+      Script += ".sh";
+      llvm::raw_fd_ostream ScriptOS(Script.c_str(), Err,
+                                    llvm::raw_fd_ostream::F_Excl |
+                                    llvm::raw_fd_ostream::F_Binary);
+      if (!Err.empty()) {
+        Diag(clang::diag::note_drv_command_failed_diag_msg)
+          << "Error generating run script: " + Script + " " + Err;
+      } else {
+        ScriptOS << Cmd;
+        Diag(clang::diag::note_drv_command_failed_diag_msg) << Script;
+      }
+    }
+  } else {
+    // Failure, remove preprocessed files.
+    if (!C.getArgs().hasArg(options::OPT_save_temps))
+      C.CleanupFileList(C.getTempFiles(), true);
+
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+      << "Error generating preprocessed source(s).";
+  }
+}
+
+int Driver::ExecuteCompilation(const Compilation &C,
+                               const Command *&FailingCommand) const {
+  // Just print if -### was present.
+  if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH)) {
+    C.PrintJob(llvm::errs(), C.getJobs(), "\n", true);
+    return 0;
+  }
+
+  // If there were errors building the compilation, quit now.
+  if (Diags.hasErrorOccurred())
+    return 1;
+
+  int Res = C.ExecuteJob(C.getJobs(), FailingCommand);
+
+  // Remove temp files.
+  C.CleanupFileList(C.getTempFiles());
+
+  // If the command succeeded, we are done.
+  if (Res == 0)
+    return Res;
+
+  // Otherwise, remove result files as well.
+  if (!C.getArgs().hasArg(options::OPT_save_temps)) {
+    C.CleanupFileList(C.getResultFiles(), true);
+
+    // Failure result files are valid unless we crashed.
+    if (Res < 0) {
+      C.CleanupFileList(C.getFailureResultFiles(), true);
+#ifdef _WIN32
+      // Exit status should not be negative on Win32,
+      // unless abnormal termination.
+      Res = 1;
+#endif
+    }
+  }
+
+  // Print extra information about abnormal failures, if possible.
+  //
+  // This is ad-hoc, but we don't want to be excessively noisy. If the result
+  // status was 1, assume the command failed normally. In particular, if it was
+  // the compiler then assume it gave a reasonable error code. Failures in other
+  // tools are less common, and they generally have worse diagnostics, so always
+  // print the diagnostic there.
+  const Tool &FailingTool = FailingCommand->getCreator();
+
+  if (!FailingCommand->getCreator().hasGoodDiagnostics() || Res != 1) {
+    // FIXME: See FIXME above regarding result code interpretation.
+    if (Res < 0)
+      Diag(clang::diag::err_drv_command_signalled)
+        << FailingTool.getShortName();
+    else
+      Diag(clang::diag::err_drv_command_failed)
+        << FailingTool.getShortName() << Res;
+  }
+
+  return Res;
+}
+
+void Driver::PrintOptions(const ArgList &Args) const {
+  unsigned i = 0;
+  for (ArgList::const_iterator it = Args.begin(), ie = Args.end();
+       it != ie; ++it, ++i) {
+    Arg *A = *it;
+    llvm::errs() << "Option " << i << " - "
+                 << "Name: \"" << A->getOption().getName() << "\", "
+                 << "Values: {";
+    for (unsigned j = 0; j < A->getNumValues(); ++j) {
+      if (j)
+        llvm::errs() << ", ";
+      llvm::errs() << '"' << A->getValue(Args, j) << '"';
+    }
+    llvm::errs() << "}\n";
+  }
+}
+
+void Driver::PrintHelp(bool ShowHidden) const {
+  getOpts().PrintHelp(llvm::outs(), Name.c_str(), DriverTitle.c_str(),
+                      ShowHidden);
+}
+
+void Driver::PrintVersion(const Compilation &C, raw_ostream &OS) const {
+  // FIXME: The following handlers should use a callback mechanism, we don't
+  // know what the client would like to do.
+  OS << getClangFullVersion() << '\n';
+  const ToolChain &TC = C.getDefaultToolChain();
+  OS << "Target: " << TC.getTripleString() << '\n';
+
+  // Print the threading model.
+  //
+  // FIXME: Implement correctly.
+  OS << "Thread model: " << "posix" << '\n';
+}
+
+/// PrintDiagnosticCategories - Implement the --print-diagnostic-categories
+/// option.
+static void PrintDiagnosticCategories(raw_ostream &OS) {
+  // Skip the empty category.
+  for (unsigned i = 1, max = DiagnosticIDs::getNumberOfCategories();
+       i != max; ++i)
+    OS << i << ',' << DiagnosticIDs::getCategoryNameFromID(i) << '\n';
+}
+
+bool Driver::HandleImmediateArgs(const Compilation &C) {
+  // The order these options are handled in gcc is all over the place, but we
+  // don't expect inconsistencies w.r.t. that to matter in practice.
+
+  if (C.getArgs().hasArg(options::OPT_dumpmachine)) {
+    llvm::outs() << C.getDefaultToolChain().getTripleString() << '\n';
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT_dumpversion)) {
+    // Since -dumpversion is only implemented for pedantic GCC compatibility, we
+    // return an answer which matches our definition of __VERSION__.
+    //
+    // If we want to return a more correct answer some day, then we should
+    // introduce a non-pedantically GCC compatible mode to Clang in which we
+    // provide sensible definitions for -dumpversion, __VERSION__, etc.
+    llvm::outs() << "4.2.1\n";
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT__print_diagnostic_categories)) {
+    PrintDiagnosticCategories(llvm::outs());
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT__help) ||
+      C.getArgs().hasArg(options::OPT__help_hidden)) {
+    PrintHelp(C.getArgs().hasArg(options::OPT__help_hidden));
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT__version)) {
+    // Follow gcc behavior and use stdout for --version and stderr for -v.
+    PrintVersion(C, llvm::outs());
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT_v) ||
+      C.getArgs().hasArg(options::OPT__HASH_HASH_HASH)) {
+    PrintVersion(C, llvm::errs());
+    SuppressMissingInputWarning = true;
+  }
+
+  const ToolChain &TC = C.getDefaultToolChain();
+  if (C.getArgs().hasArg(options::OPT_print_search_dirs)) {
+    llvm::outs() << "programs: =";
+    for (ToolChain::path_list::const_iterator it = TC.getProgramPaths().begin(),
+           ie = TC.getProgramPaths().end(); it != ie; ++it) {
+      if (it != TC.getProgramPaths().begin())
+        llvm::outs() << ':';
+      llvm::outs() << *it;
+    }
+    llvm::outs() << "\n";
+    llvm::outs() << "libraries: =" << ResourceDir;
+
+    StringRef sysroot = C.getSysRoot();
+
+    for (ToolChain::path_list::const_iterator it = TC.getFilePaths().begin(),
+           ie = TC.getFilePaths().end(); it != ie; ++it) {
+      llvm::outs() << ':';
+      const char *path = it->c_str();
+      if (path[0] == '=')
+        llvm::outs() << sysroot << path + 1;
+      else
+        llvm::outs() << path;
+    }
+    llvm::outs() << "\n";
+    return false;
+  }
+
+  // FIXME: The following handlers should use a callback mechanism, we don't
+  // know what the client would like to do.
+  if (Arg *A = C.getArgs().getLastArg(options::OPT_print_file_name_EQ)) {
+    llvm::outs() << GetFilePath(A->getValue(C.getArgs()), TC) << "\n";
+    return false;
+  }
+
+  if (Arg *A = C.getArgs().getLastArg(options::OPT_print_prog_name_EQ)) {
+    llvm::outs() << GetProgramPath(A->getValue(C.getArgs()), TC) << "\n";
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT_print_libgcc_file_name)) {
+    llvm::outs() << GetFilePath("libgcc.a", TC) << "\n";
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT_print_multi_lib)) {
+    // FIXME: We need tool chain support for this.
+    llvm::outs() << ".;\n";
+
+    switch (C.getDefaultToolChain().getTriple().getArch()) {
+    default:
+      break;
+
+    case llvm::Triple::x86_64:
+      llvm::outs() << "x86_64;@m64" << "\n";
+      break;
+
+    case llvm::Triple::ppc64:
+      llvm::outs() << "ppc64;@m64" << "\n";
+      break;
+    }
+    return false;
+  }
+
+  // FIXME: What is the difference between print-multi-directory and
+  // print-multi-os-directory?
+  if (C.getArgs().hasArg(options::OPT_print_multi_directory) ||
+      C.getArgs().hasArg(options::OPT_print_multi_os_directory)) {
+    switch (C.getDefaultToolChain().getTriple().getArch()) {
+    default:
+    case llvm::Triple::x86:
+    case llvm::Triple::ppc:
+      llvm::outs() << "." << "\n";
+      break;
+
+    case llvm::Triple::x86_64:
+      llvm::outs() << "x86_64" << "\n";
+      break;
+
+    case llvm::Triple::ppc64:
+      llvm::outs() << "ppc64" << "\n";
+      break;
+    }
+    return false;
+  }
+
+  return true;
+}
+
+static unsigned PrintActions1(const Compilation &C, Action *A,
+                              std::map<Action*, unsigned> &Ids) {
+  if (Ids.count(A))
+    return Ids[A];
+
+  std::string str;
+  llvm::raw_string_ostream os(str);
+
+  os << Action::getClassName(A->getKind()) << ", ";
+  if (InputAction *IA = dyn_cast<InputAction>(A)) {
+    os << "\"" << IA->getInputArg().getValue(C.getArgs()) << "\"";
+  } else if (BindArchAction *BIA = dyn_cast<BindArchAction>(A)) {
+    os << '"' << (BIA->getArchName() ? BIA->getArchName() :
+                  C.getDefaultToolChain().getArchName()) << '"'
+       << ", {" << PrintActions1(C, *BIA->begin(), Ids) << "}";
+  } else {
+    os << "{";
+    for (Action::iterator it = A->begin(), ie = A->end(); it != ie;) {
+      os << PrintActions1(C, *it, Ids);
+      ++it;
+      if (it != ie)
+        os << ", ";
+    }
+    os << "}";
+  }
+
+  unsigned Id = Ids.size();
+  Ids[A] = Id;
+  llvm::errs() << Id << ": " << os.str() << ", "
+               << types::getTypeName(A->getType()) << "\n";
+
+  return Id;
+}
+
+void Driver::PrintActions(const Compilation &C) const {
+  std::map<Action*, unsigned> Ids;
+  for (ActionList::const_iterator it = C.getActions().begin(),
+         ie = C.getActions().end(); it != ie; ++it)
+    PrintActions1(C, *it, Ids);
+}
+
+/// \brief Check whether the given input tree contains any compilation or
+/// assembly actions.
+static bool ContainsCompileOrAssembleAction(const Action *A) {
+  if (isa<CompileJobAction>(A) || isa<AssembleJobAction>(A))
+    return true;
+
+  for (Action::const_iterator it = A->begin(), ie = A->end(); it != ie; ++it)
+    if (ContainsCompileOrAssembleAction(*it))
+      return true;
+
+  return false;
+}
+
+void Driver::BuildUniversalActions(const ToolChain &TC,
+                                   const DerivedArgList &Args,
+                                   const InputList &BAInputs,
+                                   ActionList &Actions) const {
+  llvm::PrettyStackTraceString CrashInfo("Building universal build actions");
+  // Collect the list of architectures. Duplicates are allowed, but should only
+  // be handled once (in the order seen).
+  llvm::StringSet<> ArchNames;
+  SmallVector<const char *, 4> Archs;
+  for (ArgList::const_iterator it = Args.begin(), ie = Args.end();
+       it != ie; ++it) {
+    Arg *A = *it;
+
+    if (A->getOption().matches(options::OPT_arch)) {
+      // Validate the option here; we don't save the type here because its
+      // particular spelling may participate in other driver choices.
+      llvm::Triple::ArchType Arch =
+        llvm::Triple::getArchTypeForDarwinArchName(A->getValue(Args));
+      if (Arch == llvm::Triple::UnknownArch) {
+        Diag(clang::diag::err_drv_invalid_arch_name)
+          << A->getAsString(Args);
+        continue;
+      }
+
+      A->claim();
+      if (ArchNames.insert(A->getValue(Args)))
+        Archs.push_back(A->getValue(Args));
+    }
+  }
+
+  // When there is no explicit arch for this platform, make sure we still bind
+  // the architecture (to the default) so that -Xarch_ is handled correctly.
+  if (!Archs.size())
+    Archs.push_back(0);
+
+  // FIXME: We killed off some others but these aren't yet detected in a
+  // functional manner. If we added information to jobs about which "auxiliary"
+  // files they wrote then we could detect the conflict these cause downstream.
+  if (Archs.size() > 1) {
+    // No recovery needed, the point of this is just to prevent
+    // overwriting the same files.
+    if (const Arg *A = Args.getLastArg(options::OPT_save_temps))
+      Diag(clang::diag::err_drv_invalid_opt_with_multiple_archs)
+        << A->getAsString(Args);
+  }
+
+  ActionList SingleActions;
+  BuildActions(TC, Args, BAInputs, SingleActions);
+
+  // Add in arch bindings for every top level action, as well as lipo and
+  // dsymutil steps if needed.
+  for (unsigned i = 0, e = SingleActions.size(); i != e; ++i) {
+    Action *Act = SingleActions[i];
+
+    // Make sure we can lipo this kind of output. If not (and it is an actual
+    // output) then we disallow, since we can't create an output file with the
+    // right name without overwriting it. We could remove this oddity by just
+    // changing the output names to include the arch, which would also fix
+    // -save-temps. Compatibility wins for now.
+
+    if (Archs.size() > 1 && !types::canLipoType(Act->getType()))
+      Diag(clang::diag::err_drv_invalid_output_with_multiple_archs)
+        << types::getTypeName(Act->getType());
+
+    ActionList Inputs;
+    for (unsigned i = 0, e = Archs.size(); i != e; ++i) {
+      Inputs.push_back(new BindArchAction(Act, Archs[i]));
+      if (i != 0)
+        Inputs.back()->setOwnsInputs(false);
+    }
+
+    // Lipo if necessary, we do it this way because we need to set the arch flag
+    // so that -Xarch_ gets overwritten.
+    if (Inputs.size() == 1 || Act->getType() == types::TY_Nothing)
+      Actions.append(Inputs.begin(), Inputs.end());
+    else
+      Actions.push_back(new LipoJobAction(Inputs, Act->getType()));
+
+    // Handle debug info queries.
+    Arg *A = Args.getLastArg(options::OPT_g_Group);
+    if (A && !A->getOption().matches(options::OPT_g0) &&
+        !A->getOption().matches(options::OPT_gstabs) &&
+        ContainsCompileOrAssembleAction(Actions.back())) {
+ 
+      // Add a 'dsymutil' step if necessary, when debug info is enabled and we
+      // have a compile input. We need to run 'dsymutil' ourselves in such cases
+      // because the debug info will refer to a temporary object file which is
+      // will be removed at the end of the compilation process.
+      if (Act->getType() == types::TY_Image) {
+        ActionList Inputs;
+        Inputs.push_back(Actions.back());
+        Actions.pop_back();
+        Actions.push_back(new DsymutilJobAction(Inputs, types::TY_dSYM));
+      }
+
+      // Verify the output (debug information only) if we passed '-verify'.
+      if (Args.hasArg(options::OPT_verify)) {
+        ActionList VerifyInputs;
+        VerifyInputs.push_back(Actions.back());
+        Actions.pop_back();
+        Actions.push_back(new VerifyJobAction(VerifyInputs,
+                                              types::TY_Nothing));
+      }
+    }
+  }
+}
+
+// Construct a the list of inputs and their types.
+void Driver::BuildInputs(const ToolChain &TC, const DerivedArgList &Args,
+                         InputList &Inputs) const {
+  // Track the current user specified (-x) input. We also explicitly track the
+  // argument used to set the type; we only want to claim the type when we
+  // actually use it, so we warn about unused -x arguments.
+  types::ID InputType = types::TY_Nothing;
+  Arg *InputTypeArg = 0;
+
+  for (ArgList::const_iterator it = Args.begin(), ie = Args.end();
+       it != ie; ++it) {
+    Arg *A = *it;
+
+    if (isa<InputOption>(A->getOption())) {
+      const char *Value = A->getValue(Args);
+      types::ID Ty = types::TY_INVALID;
+
+      // Infer the input type if necessary.
+      if (InputType == types::TY_Nothing) {
+        // If there was an explicit arg for this, claim it.
+        if (InputTypeArg)
+          InputTypeArg->claim();
+
+        // stdin must be handled specially.
+        if (memcmp(Value, "-", 2) == 0) {
+          // If running with -E, treat as a C input (this changes the builtin
+          // macros, for example). This may be overridden by -ObjC below.
+          //
+          // Otherwise emit an error but still use a valid type to avoid
+          // spurious errors (e.g., no inputs).
+          if (!Args.hasArgNoClaim(options::OPT_E) && !CCCIsCPP)
+            Diag(clang::diag::err_drv_unknown_stdin_type);
+          Ty = types::TY_C;
+        } else {
+          // Otherwise lookup by extension.
+          // Fallback is C if invoked as C preprocessor or Object otherwise.
+          // We use a host hook here because Darwin at least has its own
+          // idea of what .s is.
+          if (const char *Ext = strrchr(Value, '.'))
+            Ty = TC.LookupTypeForExtension(Ext + 1);
+
+          if (Ty == types::TY_INVALID) {
+            if (CCCIsCPP)
+              Ty = types::TY_C;
+            else
+              Ty = types::TY_Object;
+          }
+
+          // If the driver is invoked as C++ compiler (like clang++ or c++) it
+          // should autodetect some input files as C++ for g++ compatibility.
+          if (CCCIsCXX) {
+            types::ID OldTy = Ty;
+            Ty = types::lookupCXXTypeForCType(Ty);
+
+            if (Ty != OldTy)
+              Diag(clang::diag::warn_drv_treating_input_as_cxx)
+                << getTypeName(OldTy) << getTypeName(Ty);
+          }
+        }
+
+        // -ObjC and -ObjC++ override the default language, but only for "source
+        // files". We just treat everything that isn't a linker input as a
+        // source file.
+        //
+        // FIXME: Clean this up if we move the phase sequence into the type.
+        if (Ty != types::TY_Object) {
+          if (Args.hasArg(options::OPT_ObjC))
+            Ty = types::TY_ObjC;
+          else if (Args.hasArg(options::OPT_ObjCXX))
+            Ty = types::TY_ObjCXX;
+        }
+      } else {
+        assert(InputTypeArg && "InputType set w/o InputTypeArg");
+        InputTypeArg->claim();
+        Ty = InputType;
+      }
+
+      // Check that the file exists, if enabled.
+      if (CheckInputsExist && memcmp(Value, "-", 2) != 0) {
+        SmallString<64> Path(Value);
+        if (Arg *WorkDir = Args.getLastArg(options::OPT_working_directory)) {
+          SmallString<64> Directory(WorkDir->getValue(Args));
+          if (llvm::sys::path::is_absolute(Directory.str())) {
+            llvm::sys::path::append(Directory, Value);
+            Path.assign(Directory);
+          }
+        }
+
+        bool exists = false;
+        if (llvm::sys::fs::exists(Path.c_str(), exists) || !exists)
+          Diag(clang::diag::err_drv_no_such_file) << Path.str();
+        else
+          Inputs.push_back(std::make_pair(Ty, A));
+      } else
+        Inputs.push_back(std::make_pair(Ty, A));
+
+    } else if (A->getOption().isLinkerInput()) {
+      // Just treat as object type, we could make a special type for this if
+      // necessary.
+      Inputs.push_back(std::make_pair(types::TY_Object, A));
+
+    } else if (A->getOption().matches(options::OPT_x)) {
+      InputTypeArg = A;
+      InputType = types::lookupTypeForTypeSpecifier(A->getValue(Args));
+      A->claim();
+
+      // Follow gcc behavior and treat as linker input for invalid -x
+      // options. Its not clear why we shouldn't just revert to unknown; but
+      // this isn't very important, we might as well be bug compatible.
+      if (!InputType) {
+        Diag(clang::diag::err_drv_unknown_language) << A->getValue(Args);
+        InputType = types::TY_Object;
+      }
+    }
+  }
+  if (CCCIsCPP && Inputs.empty()) {
+    // If called as standalone preprocessor, stdin is processed
+    // if no other input is present.
+    unsigned Index = Args.getBaseArgs().MakeIndex("-");
+    Arg *A = Opts->ParseOneArg(Args, Index);
+    A->claim();
+    Inputs.push_back(std::make_pair(types::TY_C, A));
+  }
+}
+
+void Driver::BuildActions(const ToolChain &TC, const DerivedArgList &Args,
+                          const InputList &Inputs, ActionList &Actions) const {
+  llvm::PrettyStackTraceString CrashInfo("Building compilation actions");
+
+  if (!SuppressMissingInputWarning && Inputs.empty()) {
+    Diag(clang::diag::err_drv_no_input_files);
+    return;
+  }
+
+  Arg *FinalPhaseArg;
+  phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg);
+
+  // Reject -Z* at the top level, these options should never have been exposed
+  // by gcc.
+  if (Arg *A = Args.getLastArg(options::OPT_Z_Joined))
+    Diag(clang::diag::err_drv_use_of_Z_option) << A->getAsString(Args);
+
+  // Construct the actions to perform.
+  ActionList LinkerInputs;
+  unsigned NumSteps = 0;
+  for (unsigned i = 0, e = Inputs.size(); i != e; ++i) {
+    types::ID InputType = Inputs[i].first;
+    const Arg *InputArg = Inputs[i].second;
+
+    NumSteps = types::getNumCompilationPhases(InputType);
+    assert(NumSteps && "Invalid number of steps!");
+
+    // If the first step comes after the final phase we are doing as part of
+    // this compilation, warn the user about it.
+    phases::ID InitialPhase = types::getCompilationPhase(InputType, 0);
+    if (InitialPhase > FinalPhase) {
+      // Claim here to avoid the more general unused warning.
+      InputArg->claim();
+
+      // Suppress all unused style warnings with -Qunused-arguments
+      if (Args.hasArg(options::OPT_Qunused_arguments))
+        continue;
+
+      // Special case '-E' warning on a previously preprocessed file to make
+      // more sense.
+      if (InitialPhase == phases::Compile && FinalPhase == phases::Preprocess &&
+          getPreprocessedType(InputType) == types::TY_INVALID)
+        Diag(clang::diag::warn_drv_preprocessed_input_file_unused)
+          << InputArg->getAsString(Args)
+          << FinalPhaseArg->getOption().getName();
+      else
+        Diag(clang::diag::warn_drv_input_file_unused)
+          << InputArg->getAsString(Args)
+          << getPhaseName(InitialPhase)
+          << FinalPhaseArg->getOption().getName();
+      continue;
+    }
+
+    // Build the pipeline for this file.
+    OwningPtr<Action> Current(new InputAction(*InputArg, InputType));
+    for (unsigned i = 0; i != NumSteps; ++i) {
+      phases::ID Phase = types::getCompilationPhase(InputType, i);
+
+      // We are done if this step is past what the user requested.
+      if (Phase > FinalPhase)
+        break;
+
+      // Queue linker inputs.
+      if (Phase == phases::Link) {
+        assert(i + 1 == NumSteps && "linking must be final compilation step.");
+        LinkerInputs.push_back(Current.take());
+        break;
+      }
+
+      // Some types skip the assembler phase (e.g., llvm-bc), but we can't
+      // encode this in the steps because the intermediate type depends on
+      // arguments. Just special case here.
+      if (Phase == phases::Assemble && Current->getType() != types::TY_PP_Asm)
+        continue;
+
+      // Otherwise construct the appropriate action.
+      Current.reset(ConstructPhaseAction(Args, Phase, Current.take()));
+      if (Current->getType() == types::TY_Nothing)
+        break;
+    }
+
+    // If we ended with something, add to the output list.
+    if (Current)
+      Actions.push_back(Current.take());
+  }
+
+  // Add a link action if necessary.
+  if (!LinkerInputs.empty())
+    Actions.push_back(new LinkJobAction(LinkerInputs, types::TY_Image));
+
+  // If we are linking, claim any options which are obviously only used for
+  // compilation.
+  if (FinalPhase == phases::Link && (NumSteps == 1))
+    Args.ClaimAllArgs(options::OPT_CompileOnly_Group);
+}
+
+Action *Driver::ConstructPhaseAction(const ArgList &Args, phases::ID Phase,
+                                     Action *Input) const {
+  llvm::PrettyStackTraceString CrashInfo("Constructing phase actions");
+  // Build the appropriate action.
+  switch (Phase) {
+  case phases::Link: llvm_unreachable("link action invalid here.");
+  case phases::Preprocess: {
+    types::ID OutputTy;
+    // -{M, MM} alter the output type.
+    if (Args.hasArg(options::OPT_M, options::OPT_MM)) {
+      OutputTy = types::TY_Dependencies;
+    } else {
+      OutputTy = types::getPreprocessedType(Input->getType());
+      assert(OutputTy != types::TY_INVALID &&
+             "Cannot preprocess this input type!");
+    }
+    return new PreprocessJobAction(Input, OutputTy);
+  }
+  case phases::Precompile:
+    return new PrecompileJobAction(Input, types::TY_PCH);
+  case phases::Compile: {
+    if (Args.hasArg(options::OPT_fsyntax_only)) {
+      return new CompileJobAction(Input, types::TY_Nothing);
+    } else if (Args.hasArg(options::OPT_rewrite_objc)) {
+      return new CompileJobAction(Input, types::TY_RewrittenObjC);
+    } else if (Args.hasArg(options::OPT_rewrite_legacy_objc)) {
+      return new CompileJobAction(Input, types::TY_RewrittenLegacyObjC);
+    } else if (Args.hasArg(options::OPT__analyze, options::OPT__analyze_auto)) {
+      return new AnalyzeJobAction(Input, types::TY_Plist);
+    } else if (Args.hasArg(options::OPT__migrate)) {
+      return new MigrateJobAction(Input, types::TY_Remap);
+    } else if (Args.hasArg(options::OPT_emit_ast)) {
+      return new CompileJobAction(Input, types::TY_AST);
+    } else if (IsUsingLTO(Args)) {
+      types::ID Output =
+        Args.hasArg(options::OPT_S) ? types::TY_LTO_IR : types::TY_LTO_BC;
+      return new CompileJobAction(Input, Output);
+    } else {
+      return new CompileJobAction(Input, types::TY_PP_Asm);
+    }
+  }
+  case phases::Assemble:
+    return new AssembleJobAction(Input, types::TY_Object);
+  }
+
+  llvm_unreachable("invalid phase in ConstructPhaseAction");
+}
+
+bool Driver::IsUsingLTO(const ArgList &Args) const {
+  // Check for -emit-llvm or -flto.
+  if (Args.hasArg(options::OPT_emit_llvm) ||
+      Args.hasFlag(options::OPT_flto, options::OPT_fno_lto, false))
+    return true;
+
+  // Check for -O4.
+  if (const Arg *A = Args.getLastArg(options::OPT_O_Group))
+      return A->getOption().matches(options::OPT_O4);
+
+  return false;
+}
+
+void Driver::BuildJobs(Compilation &C) const {
+  llvm::PrettyStackTraceString CrashInfo("Building compilation jobs");
+
+  Arg *FinalOutput = C.getArgs().getLastArg(options::OPT_o);
+
+  // It is an error to provide a -o option if we are making multiple output
+  // files.
+  if (FinalOutput) {
+    unsigned NumOutputs = 0;
+    for (ActionList::const_iterator it = C.getActions().begin(),
+           ie = C.getActions().end(); it != ie; ++it)
+      if ((*it)->getType() != types::TY_Nothing)
+        ++NumOutputs;
+
+    if (NumOutputs > 1) {
+      Diag(clang::diag::err_drv_output_argument_with_multiple_files);
+      FinalOutput = 0;
+    }
+  }
+
+  for (ActionList::const_iterator it = C.getActions().begin(),
+         ie = C.getActions().end(); it != ie; ++it) {
+    Action *A = *it;
+
+    // If we are linking an image for multiple archs then the linker wants
+    // -arch_multiple and -final_output <final image name>. Unfortunately, this
+    // doesn't fit in cleanly because we have to pass this information down.
+    //
+    // FIXME: This is a hack; find a cleaner way to integrate this into the
+    // process.
+    const char *LinkingOutput = 0;
+    if (isa<LipoJobAction>(A)) {
+      if (FinalOutput)
+        LinkingOutput = FinalOutput->getValue(C.getArgs());
+      else
+        LinkingOutput = DefaultImageName.c_str();
+    }
+
+    InputInfo II;
+    BuildJobsForAction(C, A, &C.getDefaultToolChain(),
+                       /*BoundArch*/0,
+                       /*AtTopLevel*/ true,
+                       /*LinkingOutput*/ LinkingOutput,
+                       II);
+  }
+
+  // If the user passed -Qunused-arguments or there were errors, don't warn
+  // about any unused arguments.
+  if (Diags.hasErrorOccurred() ||
+      C.getArgs().hasArg(options::OPT_Qunused_arguments))
+    return;
+
+  // Claim -### here.
+  (void) C.getArgs().hasArg(options::OPT__HASH_HASH_HASH);
+
+  for (ArgList::const_iterator it = C.getArgs().begin(), ie = C.getArgs().end();
+       it != ie; ++it) {
+    Arg *A = *it;
+
+    // FIXME: It would be nice to be able to send the argument to the
+    // DiagnosticsEngine, so that extra values, position, and so on could be
+    // printed.
+    if (!A->isClaimed()) {
+      if (A->getOption().hasNoArgumentUnused())
+        continue;
+
+      // Suppress the warning automatically if this is just a flag, and it is an
+      // instance of an argument we already claimed.
+      const Option &Opt = A->getOption();
+      if (isa<FlagOption>(Opt)) {
+        bool DuplicateClaimed = false;
+
+        for (arg_iterator it = C.getArgs().filtered_begin(&Opt),
+               ie = C.getArgs().filtered_end(); it != ie; ++it) {
+          if ((*it)->isClaimed()) {
+            DuplicateClaimed = true;
+            break;
+          }
+        }
+
+        if (DuplicateClaimed)
+          continue;
+      }
+
+      Diag(clang::diag::warn_drv_unused_argument)
+        << A->getAsString(C.getArgs());
+    }
+  }
+}
+
+static const Tool &SelectToolForJob(Compilation &C, const ToolChain *TC,
+                                    const JobAction *JA,
+                                    const ActionList *&Inputs) {
+  const Tool *ToolForJob = 0;
+
+  // See if we should look for a compiler with an integrated assembler. We match
+  // bottom up, so what we are actually looking for is an assembler job with a
+  // compiler input.
+
+  if (C.getArgs().hasFlag(options::OPT_integrated_as,
+                          options::OPT_no_integrated_as,
+                          TC->IsIntegratedAssemblerDefault()) &&
+      !C.getArgs().hasArg(options::OPT_save_temps) &&
+      isa<AssembleJobAction>(JA) &&
+      Inputs->size() == 1 && isa<CompileJobAction>(*Inputs->begin())) {
+    const Tool &Compiler = TC->SelectTool(
+      C, cast<JobAction>(**Inputs->begin()), (*Inputs)[0]->getInputs());
+    if (Compiler.hasIntegratedAssembler()) {
+      Inputs = &(*Inputs)[0]->getInputs();
+      ToolForJob = &Compiler;
+    }
+  }
+
+  // Otherwise use the tool for the current job.
+  if (!ToolForJob)
+    ToolForJob = &TC->SelectTool(C, *JA, *Inputs);
+
+  // See if we should use an integrated preprocessor. We do so when we have
+  // exactly one input, since this is the only use case we care about
+  // (irrelevant since we don't support combine yet).
+  if (Inputs->size() == 1 && isa<PreprocessJobAction>(*Inputs->begin()) &&
+      !C.getArgs().hasArg(options::OPT_no_integrated_cpp) &&
+      !C.getArgs().hasArg(options::OPT_traditional_cpp) &&
+      !C.getArgs().hasArg(options::OPT_save_temps) &&
+      ToolForJob->hasIntegratedCPP())
+    Inputs = &(*Inputs)[0]->getInputs();
+
+  return *ToolForJob;
+}
+
+void Driver::BuildJobsForAction(Compilation &C,
+                                const Action *A,
+                                const ToolChain *TC,
+                                const char *BoundArch,
+                                bool AtTopLevel,
+                                const char *LinkingOutput,
+                                InputInfo &Result) const {
+  llvm::PrettyStackTraceString CrashInfo("Building compilation jobs");
+
+  if (const InputAction *IA = dyn_cast<InputAction>(A)) {
+    // FIXME: It would be nice to not claim this here; maybe the old scheme of
+    // just using Args was better?
+    const Arg &Input = IA->getInputArg();
+    Input.claim();
+    if (Input.getOption().matches(options::OPT_INPUT)) {
+      const char *Name = Input.getValue(C.getArgs());
+      Result = InputInfo(Name, A->getType(), Name);
+    } else
+      Result = InputInfo(&Input, A->getType(), "");
+    return;
+  }
+
+  if (const BindArchAction *BAA = dyn_cast<BindArchAction>(A)) {
+    const ToolChain *TC = &C.getDefaultToolChain();
+
+    if (BAA->getArchName())
+      TC = &getToolChain(C.getArgs(), BAA->getArchName());
+
+    BuildJobsForAction(C, *BAA->begin(), TC, BAA->getArchName(),
+                       AtTopLevel, LinkingOutput, Result);
+    return;
+  }
+
+  const ActionList *Inputs = &A->getInputs();
+
+  const JobAction *JA = cast<JobAction>(A);
+  const Tool &T = SelectToolForJob(C, TC, JA, Inputs);
+
+  // Only use pipes when there is exactly one input.
+  InputInfoList InputInfos;
+  for (ActionList::const_iterator it = Inputs->begin(), ie = Inputs->end();
+       it != ie; ++it) {
+    // Treat dsymutil sub-jobs as being at the top-level too, they shouldn't get
+    // temporary output names.
+    //
+    // FIXME: Clean this up.
+    bool SubJobAtTopLevel = false;
+    if (AtTopLevel && isa<DsymutilJobAction>(A))
+      SubJobAtTopLevel = true;
+
+    // Also treat verify sub-jobs as being at the top-level. They don't
+    // produce any output and so don't need temporary output names.
+    if (AtTopLevel && isa<VerifyJobAction>(A))
+      SubJobAtTopLevel = true;
+
+    InputInfo II;
+    BuildJobsForAction(C, *it, TC, BoundArch,
+                       SubJobAtTopLevel, LinkingOutput, II);
+    InputInfos.push_back(II);
+  }
+
+  // Always use the first input as the base input.
+  const char *BaseInput = InputInfos[0].getBaseInput();
+
+  // ... except dsymutil actions, which use their actual input as the base
+  // input.
+  if (JA->getType() == types::TY_dSYM)
+    BaseInput = InputInfos[0].getFilename();
+
+  // Determine the place to write output to, if any.
+  if (JA->getType() == types::TY_Nothing) {
+    Result = InputInfo(A->getType(), BaseInput);
+  } else {
+    Result = InputInfo(GetNamedOutputPath(C, *JA, BaseInput, AtTopLevel),
+                       A->getType(), BaseInput);
+  }
+
+  if (CCCPrintBindings && !CCGenDiagnostics) {
+    llvm::errs() << "# \"" << T.getToolChain().getTripleString() << '"'
+                 << " - \"" << T.getName() << "\", inputs: [";
+    for (unsigned i = 0, e = InputInfos.size(); i != e; ++i) {
+      llvm::errs() << InputInfos[i].getAsString();
+      if (i + 1 != e)
+        llvm::errs() << ", ";
+    }
+    llvm::errs() << "], output: " << Result.getAsString() << "\n";
+  } else {
+    T.ConstructJob(C, *JA, Result, InputInfos,
+                   C.getArgsForToolChain(TC, BoundArch), LinkingOutput);
+  }
+}
+
+const char *Driver::GetNamedOutputPath(Compilation &C,
+                                       const JobAction &JA,
+                                       const char *BaseInput,
+                                       bool AtTopLevel) const {
+  llvm::PrettyStackTraceString CrashInfo("Computing output path");
+  // Output to a user requested destination?
+  if (AtTopLevel && !isa<DsymutilJobAction>(JA) &&
+      !isa<VerifyJobAction>(JA)) {
+    if (Arg *FinalOutput = C.getArgs().getLastArg(options::OPT_o))
+      return C.addResultFile(FinalOutput->getValue(C.getArgs()));
+  }
+
+  // Default to writing to stdout?
+  if (AtTopLevel && isa<PreprocessJobAction>(JA) && !CCGenDiagnostics)
+    return "-";
+
+  // Output to a temporary file?
+  if ((!AtTopLevel && !C.getArgs().hasArg(options::OPT_save_temps)) ||
+      CCGenDiagnostics) {
+    StringRef Name = llvm::sys::path::filename(BaseInput);
+    std::pair<StringRef, StringRef> Split = Name.split('.');
+    std::string TmpName =
+      GetTemporaryPath(Split.first, types::getTypeTempSuffix(JA.getType()));
+    return C.addTempFile(C.getArgs().MakeArgString(TmpName.c_str()));
+  }
+
+  SmallString<128> BasePath(BaseInput);
+  StringRef BaseName;
+
+  // Dsymutil actions should use the full path.
+  if (isa<DsymutilJobAction>(JA) || isa<VerifyJobAction>(JA))
+    BaseName = BasePath;
+  else
+    BaseName = llvm::sys::path::filename(BasePath);
+
+  // Determine what the derived output name should be.
+  const char *NamedOutput;
+  if (JA.getType() == types::TY_Image) {
+    NamedOutput = DefaultImageName.c_str();
+  } else {
+    const char *Suffix = types::getTypeTempSuffix(JA.getType());
+    assert(Suffix && "All types used for output should have a suffix.");
+
+    std::string::size_type End = std::string::npos;
+    if (!types::appendSuffixForType(JA.getType()))
+      End = BaseName.rfind('.');
+    std::string Suffixed(BaseName.substr(0, End));
+    Suffixed += '.';
+    Suffixed += Suffix;
+    NamedOutput = C.getArgs().MakeArgString(Suffixed.c_str());
+  }
+
+  // If we're saving temps and the temp filename conflicts with the input
+  // filename, then avoid overwriting input file.
+  if (!AtTopLevel && C.getArgs().hasArg(options::OPT_save_temps) &&
+      NamedOutput == BaseName) {
+    StringRef Name = llvm::sys::path::filename(BaseInput);
+    std::pair<StringRef, StringRef> Split = Name.split('.');
+    std::string TmpName =
+      GetTemporaryPath(Split.first, types::getTypeTempSuffix(JA.getType()));
+    return C.addTempFile(C.getArgs().MakeArgString(TmpName.c_str()));
+  }
+
+  // As an annoying special case, PCH generation doesn't strip the pathname.
+  if (JA.getType() == types::TY_PCH) {
+    llvm::sys::path::remove_filename(BasePath);
+    if (BasePath.empty())
+      BasePath = NamedOutput;
+    else
+      llvm::sys::path::append(BasePath, NamedOutput);
+    return C.addResultFile(C.getArgs().MakeArgString(BasePath.c_str()));
+  } else {
+    return C.addResultFile(NamedOutput);
+  }
+}
+
+std::string Driver::GetFilePath(const char *Name, const ToolChain &TC) const {
+  // Respect a limited subset of the '-Bprefix' functionality in GCC by
+  // attempting to use this prefix when lokup up program paths.
+  for (Driver::prefix_list::const_iterator it = PrefixDirs.begin(),
+       ie = PrefixDirs.end(); it != ie; ++it) {
+    std::string Dir(*it);
+    if (Dir.empty())
+      continue;
+    if (Dir[0] == '=')
+      Dir = SysRoot + Dir.substr(1);
+    llvm::sys::Path P(Dir);
+    P.appendComponent(Name);
+    bool Exists;
+    if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+      return P.str();
+  }
+
+  llvm::sys::Path P(ResourceDir);
+  P.appendComponent(Name);
+  bool Exists;
+  if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+    return P.str();
+
+  const ToolChain::path_list &List = TC.getFilePaths();
+  for (ToolChain::path_list::const_iterator
+         it = List.begin(), ie = List.end(); it != ie; ++it) {
+    std::string Dir(*it);
+    if (Dir.empty())
+      continue;
+    if (Dir[0] == '=')
+      Dir = SysRoot + Dir.substr(1);
+    llvm::sys::Path P(Dir);
+    P.appendComponent(Name);
+    bool Exists;
+    if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+      return P.str();
+  }
+
+  return Name;
+}
+
+static bool isPathExecutable(llvm::sys::Path &P, bool WantFile) {
+    bool Exists;
+    return (WantFile ? !llvm::sys::fs::exists(P.str(), Exists) && Exists
+                 : P.canExecute());
+}
+
+std::string Driver::GetProgramPath(const char *Name, const ToolChain &TC,
+                                   bool WantFile) const {
+  // FIXME: Needs a better variable than DefaultTargetTriple
+  std::string TargetSpecificExecutable(DefaultTargetTriple + "-" + Name);
+  // Respect a limited subset of the '-Bprefix' functionality in GCC by
+  // attempting to use this prefix when lokup up program paths.
+  for (Driver::prefix_list::const_iterator it = PrefixDirs.begin(),
+       ie = PrefixDirs.end(); it != ie; ++it) {
+    llvm::sys::Path P(*it);
+    P.appendComponent(TargetSpecificExecutable);
+    if (isPathExecutable(P, WantFile)) return P.str();
+    P.eraseComponent();
+    P.appendComponent(Name);
+    if (isPathExecutable(P, WantFile)) return P.str();
+  }
+
+  const ToolChain::path_list &List = TC.getProgramPaths();
+  for (ToolChain::path_list::const_iterator
+         it = List.begin(), ie = List.end(); it != ie; ++it) {
+    llvm::sys::Path P(*it);
+    P.appendComponent(TargetSpecificExecutable);
+    if (isPathExecutable(P, WantFile)) return P.str();
+    P.eraseComponent();
+    P.appendComponent(Name);
+    if (isPathExecutable(P, WantFile)) return P.str();
+  }
+
+  // If all else failed, search the path.
+  llvm::sys::Path
+      P(llvm::sys::Program::FindProgramByName(TargetSpecificExecutable));
+  if (!P.empty())
+    return P.str();
+
+  P = llvm::sys::Path(llvm::sys::Program::FindProgramByName(Name));
+  if (!P.empty())
+    return P.str();
+
+  return Name;
+}
+
+std::string Driver::GetTemporaryPath(StringRef Prefix, const char *Suffix) 
+  const {
+  // FIXME: This is lame; sys::Path should provide this function (in particular,
+  // it should know how to find the temporary files dir).
+  std::string Error;
+  const char *TmpDir = ::getenv("TMPDIR");
+  if (!TmpDir)
+    TmpDir = ::getenv("TEMP");
+  if (!TmpDir)
+    TmpDir = ::getenv("TMP");
+  if (!TmpDir)
+    TmpDir = "/tmp";
+  llvm::sys::Path P(TmpDir);
+  P.appendComponent(Prefix);
+  if (P.makeUnique(false, &Error)) {
+    Diag(clang::diag::err_drv_unable_to_make_temp) << Error;
+    return "";
+  }
+
+  // FIXME: Grumble, makeUnique sometimes leaves the file around!?  PR3837.
+  P.eraseFromDisk(false, 0);
+
+  P.appendSuffix(Suffix);
+  return P.str();
+}
+
+/// \brief Compute target triple from args.
+///
+/// This routine provides the logic to compute a target triple from various
+/// args passed to the driver and the default triple string.
+static llvm::Triple computeTargetTriple(StringRef DefaultTargetTriple,
+                                        const ArgList &Args,
+                                        StringRef DarwinArchName) {
+  // FIXME: Already done in Compilation *Driver::BuildCompilation
+  if (const Arg *A = Args.getLastArg(options::OPT_target))
+    DefaultTargetTriple = A->getValue(Args);
+
+  llvm::Triple Target(llvm::Triple::normalize(DefaultTargetTriple));
+
+  // Handle Darwin-specific options available here.
+  if (Target.isOSDarwin()) {
+    // If an explict Darwin arch name is given, that trumps all.
+    if (!DarwinArchName.empty()) {
+      Target.setArch(
+        llvm::Triple::getArchTypeForDarwinArchName(DarwinArchName));
+      return Target;
+    }
+
+    // Handle the Darwin '-arch' flag.
+    if (Arg *A = Args.getLastArg(options::OPT_arch)) {
+      llvm::Triple::ArchType DarwinArch
+        = llvm::Triple::getArchTypeForDarwinArchName(A->getValue(Args));
+      if (DarwinArch != llvm::Triple::UnknownArch)
+        Target.setArch(DarwinArch);
+    }
+  }
+
+  // Skip further flag support on OSes which don't support '-m32' or '-m64'.
+  if (Target.getArchName() == "tce" ||
+      Target.getOS() == llvm::Triple::AuroraUX ||
+      Target.getOS() == llvm::Triple::Minix)
+    return Target;
+
+  // Handle pseudo-target flags '-m32' and '-m64'.
+  // FIXME: Should this information be in llvm::Triple?
+  if (Arg *A = Args.getLastArg(options::OPT_m32, options::OPT_m64)) {
+    if (A->getOption().matches(options::OPT_m32)) {
+      if (Target.getArch() == llvm::Triple::x86_64)
+        Target.setArch(llvm::Triple::x86);
+      if (Target.getArch() == llvm::Triple::ppc64)
+        Target.setArch(llvm::Triple::ppc);
+    } else {
+      if (Target.getArch() == llvm::Triple::x86)
+        Target.setArch(llvm::Triple::x86_64);
+      if (Target.getArch() == llvm::Triple::ppc)
+        Target.setArch(llvm::Triple::ppc64);
+    }
+  }
+
+  return Target;
+}
+
+const ToolChain &Driver::getToolChain(const ArgList &Args,
+                                      StringRef DarwinArchName) const {
+  llvm::Triple Target = computeTargetTriple(DefaultTargetTriple, Args,
+                                            DarwinArchName);
+
+  ToolChain *&TC = ToolChains[Target.str()];
+  if (!TC) {
+    switch (Target.getOS()) {
+    case llvm::Triple::AuroraUX:
+      TC = new toolchains::AuroraUX(*this, Target, Args);
+      break;
+    case llvm::Triple::Darwin:
+    case llvm::Triple::MacOSX:
+    case llvm::Triple::IOS:
+      if (Target.getArch() == llvm::Triple::x86 ||
+          Target.getArch() == llvm::Triple::x86_64 ||
+          Target.getArch() == llvm::Triple::arm ||
+          Target.getArch() == llvm::Triple::thumb)
+        TC = new toolchains::DarwinClang(*this, Target);
+      else
+        TC = new toolchains::Darwin_Generic_GCC(*this, Target, Args);
+      break;
+    case llvm::Triple::DragonFly:
+      TC = new toolchains::DragonFly(*this, Target, Args);
+      break;
+    case llvm::Triple::OpenBSD:
+      TC = new toolchains::OpenBSD(*this, Target, Args);
+      break;
+    case llvm::Triple::NetBSD:
+      TC = new toolchains::NetBSD(*this, Target, Args);
+      break;
+    case llvm::Triple::FreeBSD:
+      TC = new toolchains::FreeBSD(*this, Target, Args);
+      break;
+    case llvm::Triple::Minix:
+      TC = new toolchains::Minix(*this, Target, Args);
+      break;
+    case llvm::Triple::Linux:
+      if (Target.getArch() == llvm::Triple::hexagon)
+        TC = new toolchains::Hexagon_TC(*this, Target);
+      else
+        TC = new toolchains::Linux(*this, Target, Args);
+      break;
+    case llvm::Triple::Solaris:
+      TC = new toolchains::Solaris(*this, Target, Args);
+      break;
+    case llvm::Triple::Win32:
+      TC = new toolchains::Windows(*this, Target);
+      break;
+    case llvm::Triple::MinGW32:
+      // FIXME: We need a MinGW toolchain. Fallthrough for now.
+    default:
+      // TCE is an OSless target
+      if (Target.getArchName() == "tce") {
+        TC = new toolchains::TCEToolChain(*this, Target);
+        break;
+      }
+
+      TC = new toolchains::Generic_GCC(*this, Target, Args);
+      break;
+    }
+  }
+  return *TC;
+}
+
+bool Driver::ShouldUseClangCompiler(const Compilation &C, const JobAction &JA,
+                                    const llvm::Triple &Triple) const {
+  // Check if user requested no clang, or clang doesn't understand this type (we
+  // only handle single inputs for now).
+  if (!CCCUseClang || JA.size() != 1 ||
+      !types::isAcceptedByClang((*JA.begin())->getType()))
+    return false;
+
+  // Otherwise make sure this is an action clang understands.
+  if (isa<PreprocessJobAction>(JA)) {
+    if (!CCCUseClangCPP) {
+      Diag(clang::diag::warn_drv_not_using_clang_cpp);
+      return false;
+    }
+  } else if (!isa<PrecompileJobAction>(JA) && !isa<CompileJobAction>(JA))
+    return false;
+
+  // Use clang for C++?
+  if (!CCCUseClangCXX && types::isCXX((*JA.begin())->getType())) {
+    Diag(clang::diag::warn_drv_not_using_clang_cxx);
+    return false;
+  }
+
+  // Always use clang for precompiling, AST generation, and rewriting,
+  // regardless of archs.
+  if (isa<PrecompileJobAction>(JA) ||
+      types::isOnlyAcceptedByClang(JA.getType()))
+    return true;
+
+  // Finally, don't use clang if this isn't one of the user specified archs to
+  // build.
+  if (!CCCClangArchs.empty() && !CCCClangArchs.count(Triple.getArch())) {
+    Diag(clang::diag::warn_drv_not_using_clang_arch) << Triple.getArchName();
+    return false;
+  }
+
+  return true;
+}
+
+/// GetReleaseVersion - Parse (([0-9]+)(.([0-9]+)(.([0-9]+)?))?)? and return the
+/// grouped values as integers. Numbers which are not provided are set to 0.
+///
+/// \return True if the entire string was parsed (9.2), or all groups were
+/// parsed (10.3.5extrastuff).
+bool Driver::GetReleaseVersion(const char *Str, unsigned &Major,
+                               unsigned &Minor, unsigned &Micro,
+                               bool &HadExtra) {
+  HadExtra = false;
+
+  Major = Minor = Micro = 0;
+  if (*Str == '\0')
+    return true;
+
+  char *End;
+  Major = (unsigned) strtol(Str, &End, 10);
+  if (*Str != '\0' && *End == '\0')
+    return true;
+  if (*End != '.')
+    return false;
+
+  Str = End+1;
+  Minor = (unsigned) strtol(Str, &End, 10);
+  if (*Str != '\0' && *End == '\0')
+    return true;
+  if (*End != '.')
+    return false;
+
+  Str = End+1;
+  Micro = (unsigned) strtol(Str, &End, 10);
+  if (*Str != '\0' && *End == '\0')
+    return true;
+  if (Str == End)
+    return false;
+  HadExtra = true;
+  return true;
+}
diff --git a/clang/lib/Driver/DriverOptions.cpp b/clang/lib/Driver/DriverOptions.cpp
new file mode 100644
index 0000000..715819d
--- /dev/null
+++ b/clang/lib/Driver/DriverOptions.cpp
@@ -0,0 +1,37 @@
+//===--- DriverOptions.cpp - Driver Options Table -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Options.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Driver/Option.h"
+
+using namespace clang::driver;
+using namespace clang::driver::options;
+
+static const OptTable::Info InfoTable[] = {
+#define OPTION(NAME, ID, KIND, GROUP, ALIAS, FLAGS, PARAM, \
+               HELPTEXT, METAVAR)   \
+  { NAME, HELPTEXT, METAVAR, Option::KIND##Class, PARAM, FLAGS, \
+    OPT_##GROUP, OPT_##ALIAS },
+#include "clang/Driver/Options.inc"
+};
+
+namespace {
+
+class DriverOptTable : public OptTable {
+public:
+  DriverOptTable()
+    : OptTable(InfoTable, sizeof(InfoTable) / sizeof(InfoTable[0])) {}
+};
+
+}
+
+OptTable *clang::driver::createDriverOptTable() {
+  return new DriverOptTable();
+}
diff --git a/clang/lib/Driver/InputInfo.h b/clang/lib/Driver/InputInfo.h
new file mode 100644
index 0000000..2a2f4b9
--- /dev/null
+++ b/clang/lib/Driver/InputInfo.h
@@ -0,0 +1,88 @@
+//===--- InputInfo.h - Input Source & Type Information ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLANG_LIB_DRIVER_INPUTINFO_H_
+#define CLANG_LIB_DRIVER_INPUTINFO_H_
+
+#include "clang/Driver/Types.h"
+
+#include <cassert>
+#include <string>
+
+namespace clang {
+namespace driver {
+
+/// InputInfo - Wrapper for information about an input source.
+class InputInfo {
+  // FIXME: The distinction between filenames and inputarg here is
+  // gross; we should probably drop the idea of a "linker
+  // input". Doing so means tweaking pipelining to still create link
+  // steps when it sees linker inputs (but not treat them as
+  // arguments), and making sure that arguments get rendered
+  // correctly.
+  enum Class {
+    Nothing,
+    Filename,
+    InputArg,
+    Pipe
+  };
+
+  union {
+    const char *Filename;
+    const Arg *InputArg;
+  } Data;
+  Class Kind;
+  types::ID Type;
+  const char *BaseInput;
+
+public:
+  InputInfo() {}
+  InputInfo(types::ID _Type, const char *_BaseInput)
+    : Kind(Nothing), Type(_Type), BaseInput(_BaseInput) {
+  }
+  InputInfo(const char *_Filename, types::ID _Type, const char *_BaseInput)
+    : Kind(Filename), Type(_Type), BaseInput(_BaseInput) {
+    Data.Filename = _Filename;
+  }
+  InputInfo(const Arg *_InputArg, types::ID _Type, const char *_BaseInput)
+    : Kind(InputArg), Type(_Type), BaseInput(_BaseInput) {
+    Data.InputArg = _InputArg;
+  }
+
+  bool isNothing() const { return Kind == Nothing; }
+  bool isFilename() const { return Kind == Filename; }
+  bool isInputArg() const { return Kind == InputArg; }
+  types::ID getType() const { return Type; }
+  const char *getBaseInput() const { return BaseInput; }
+
+  const char *getFilename() const {
+    assert(isFilename() && "Invalid accessor.");
+    return Data.Filename;
+  }
+  const Arg &getInputArg() const {
+    assert(isInputArg() && "Invalid accessor.");
+    return *Data.InputArg;
+  }
+
+  /// getAsString - Return a string name for this input, for
+  /// debugging.
+  std::string getAsString() const {
+    if (isFilename())
+      return std::string("\"") + getFilename() + '"';
+    else if (isInputArg())
+      return "(input arg)";
+    else
+      return "(nothing)";
+  }
+};
+
+} // end namespace driver
+} // end namespace clang
+
+#endif
diff --git a/clang/lib/Driver/Job.cpp b/clang/lib/Driver/Job.cpp
new file mode 100644
index 0000000..825c86a
--- /dev/null
+++ b/clang/lib/Driver/Job.cpp
@@ -0,0 +1,42 @@
+//===--- Job.cpp - Command to Execute -------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Job.h"
+
+#include "llvm/ADT/STLExtras.h"
+
+#include <cassert>
+using namespace clang::driver;
+
+Job::~Job() {}
+
+void Command::anchor() {}
+
+Command::Command(const Action &_Source, const Tool &_Creator,
+                 const char *_Executable, const ArgStringList &_Arguments)
+  : Job(CommandClass), Source(_Source), Creator(_Creator),
+    Executable(_Executable), Arguments(_Arguments)
+{
+}
+
+JobList::JobList() : Job(JobListClass) {}
+
+JobList::~JobList() {
+  for (iterator it = begin(), ie = end(); it != ie; ++it)
+    delete *it;
+}
+
+void JobList::clear() {
+  DeleteContainerPointers(Jobs);
+}
+
+void Job::addCommand(Command *C) {
+  cast<JobList>(this)->addJob(C);
+}
+
diff --git a/clang/lib/Driver/Makefile b/clang/lib/Driver/Makefile
new file mode 100644
index 0000000..454ab86
--- /dev/null
+++ b/clang/lib/Driver/Makefile
@@ -0,0 +1,13 @@
+##===- clang/lib/Driver/Makefile ---------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+CLANG_LEVEL := ../..
+LIBRARYNAME := clangDriver
+
+include $(CLANG_LEVEL)/Makefile
diff --git a/clang/lib/Driver/OptTable.cpp b/clang/lib/Driver/OptTable.cpp
new file mode 100644
index 0000000..4f5390b
--- /dev/null
+++ b/clang/lib/Driver/OptTable.cpp
@@ -0,0 +1,384 @@
+//===--- OptTable.cpp - Option Table Implementation -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/OptTable.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Option.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <algorithm>
+#include <map>
+using namespace clang::driver;
+using namespace clang::driver::options;
+using namespace clang;
+
+// Ordering on Info. The ordering is *almost* lexicographic, with two
+// exceptions. First, '\0' comes at the end of the alphabet instead of
+// the beginning (thus options precede any other options which prefix
+// them). Second, for options with the same name, the less permissive
+// version should come first; a Flag option should precede a Joined
+// option, for example.
+
+static int StrCmpOptionName(const char *A, const char *B) {
+  char a = *A, b = *B;
+  while (a == b) {
+    if (a == '\0')
+      return 0;
+
+    a = *++A;
+    b = *++B;
+  }
+
+  if (a == '\0') // A is a prefix of B.
+    return 1;
+  if (b == '\0') // B is a prefix of A.
+    return -1;
+
+  // Otherwise lexicographic.
+  return (a < b) ? -1 : 1;
+}
+
+namespace clang {
+namespace driver {
+static inline bool operator<(const OptTable::Info &A, const OptTable::Info &B) {
+  if (&A == &B)
+    return false;
+
+  if (int N = StrCmpOptionName(A.Name, B.Name))
+    return N == -1;
+
+  // Names are the same, check that classes are in order; exactly one
+  // should be joined, and it should succeed the other.
+  assert(((A.Kind == Option::JoinedClass) ^ (B.Kind == Option::JoinedClass)) &&
+         "Unexpected classes for options with same name.");
+  return B.Kind == Option::JoinedClass;
+}
+
+// Support lower_bound between info and an option name.
+static inline bool operator<(const OptTable::Info &I, const char *Name) {
+  return StrCmpOptionName(I.Name, Name) == -1;
+}
+static inline bool operator<(const char *Name, const OptTable::Info &I) {
+  return StrCmpOptionName(Name, I.Name) == -1;
+}
+}
+}
+
+//
+
+OptSpecifier::OptSpecifier(const Option *Opt) : ID(Opt->getID()) {}
+
+//
+
+OptTable::OptTable(const Info *_OptionInfos, unsigned _NumOptionInfos)
+  : OptionInfos(_OptionInfos), NumOptionInfos(_NumOptionInfos),
+    Options(new Option*[NumOptionInfos]),
+    TheInputOption(0), TheUnknownOption(0), FirstSearchableIndex(0)
+{
+  // Explicitly zero initialize the error to work around a bug in array
+  // value-initialization on MinGW with gcc 4.3.5.
+  memset(Options, 0, sizeof(*Options) * NumOptionInfos);
+
+  // Find start of normal options.
+  for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
+    unsigned Kind = getInfo(i + 1).Kind;
+    if (Kind == Option::InputClass) {
+      assert(!TheInputOption && "Cannot have multiple input options!");
+      TheInputOption = getOption(i + 1);
+    } else if (Kind == Option::UnknownClass) {
+      assert(!TheUnknownOption && "Cannot have multiple input options!");
+      TheUnknownOption = getOption(i + 1);
+    } else if (Kind != Option::GroupClass) {
+      FirstSearchableIndex = i;
+      break;
+    }
+  }
+  assert(FirstSearchableIndex != 0 && "No searchable options?");
+
+#ifndef NDEBUG
+  // Check that everything after the first searchable option is a
+  // regular option class.
+  for (unsigned i = FirstSearchableIndex, e = getNumOptions(); i != e; ++i) {
+    Option::OptionClass Kind = (Option::OptionClass) getInfo(i + 1).Kind;
+    assert((Kind != Option::InputClass && Kind != Option::UnknownClass &&
+            Kind != Option::GroupClass) &&
+           "Special options should be defined first!");
+  }
+
+  // Check that options are in order.
+  for (unsigned i = FirstSearchableIndex+1, e = getNumOptions(); i != e; ++i) {
+    if (!(getInfo(i) < getInfo(i + 1))) {
+      getOption(i)->dump();
+      getOption(i + 1)->dump();
+      llvm_unreachable("Options are not in order!");
+    }
+  }
+#endif
+}
+
+OptTable::~OptTable() {
+  for (unsigned i = 0, e = getNumOptions(); i != e; ++i)
+    delete Options[i];
+  delete[] Options;
+}
+
+Option *OptTable::CreateOption(unsigned id) const {
+  const Info &info = getInfo(id);
+  const OptionGroup *Group =
+    cast_or_null<OptionGroup>(getOption(info.GroupID));
+  const Option *Alias = getOption(info.AliasID);
+
+  Option *Opt = 0;
+  switch (info.Kind) {
+  case Option::InputClass:
+    Opt = new InputOption(id); break;
+  case Option::UnknownClass:
+    Opt = new UnknownOption(id); break;
+  case Option::GroupClass:
+    Opt = new OptionGroup(id, info.Name, Group); break;
+  case Option::FlagClass:
+    Opt = new FlagOption(id, info.Name, Group, Alias); break;
+  case Option::JoinedClass:
+    Opt = new JoinedOption(id, info.Name, Group, Alias); break;
+  case Option::SeparateClass:
+    Opt = new SeparateOption(id, info.Name, Group, Alias); break;
+  case Option::CommaJoinedClass:
+    Opt = new CommaJoinedOption(id, info.Name, Group, Alias); break;
+  case Option::MultiArgClass:
+    Opt = new MultiArgOption(id, info.Name, Group, Alias, info.Param); break;
+  case Option::JoinedOrSeparateClass:
+    Opt = new JoinedOrSeparateOption(id, info.Name, Group, Alias); break;
+  case Option::JoinedAndSeparateClass:
+    Opt = new JoinedAndSeparateOption(id, info.Name, Group, Alias); break;
+  }
+
+  if (info.Flags & DriverOption)
+    Opt->setDriverOption(true);
+  if (info.Flags & LinkerInput)
+    Opt->setLinkerInput(true);
+  if (info.Flags & NoArgumentUnused)
+    Opt->setNoArgumentUnused(true);
+  if (info.Flags & NoForward)
+    Opt->setNoForward(true);
+  if (info.Flags & RenderAsInput)
+    Opt->setNoOptAsInput(true);
+  if (info.Flags & RenderJoined) {
+    assert((info.Kind == Option::JoinedOrSeparateClass ||
+            info.Kind == Option::SeparateClass) && "Invalid option.");
+    Opt->setRenderStyle(Option::RenderJoinedStyle);
+  }
+  if (info.Flags & RenderSeparate) {
+    assert((info.Kind == Option::JoinedOrSeparateClass ||
+            info.Kind == Option::JoinedClass) && "Invalid option.");
+    Opt->setRenderStyle(Option::RenderSeparateStyle);
+  }
+  if (info.Flags & Unsupported)
+    Opt->setUnsupported(true);
+
+  return Opt;
+}
+
+Arg *OptTable::ParseOneArg(const ArgList &Args, unsigned &Index) const {
+  unsigned Prev = Index;
+  const char *Str = Args.getArgString(Index);
+
+  // Anything that doesn't start with '-' is an input, as is '-' itself.
+  if (Str[0] != '-' || Str[1] == '\0')
+    return new Arg(TheInputOption, Index++, Str);
+
+  const Info *Start = OptionInfos + FirstSearchableIndex;
+  const Info *End = OptionInfos + getNumOptions();
+
+  // Search for the first next option which could be a prefix.
+  Start = std::lower_bound(Start, End, Str);
+
+  // Options are stored in sorted order, with '\0' at the end of the
+  // alphabet. Since the only options which can accept a string must
+  // prefix it, we iteratively search for the next option which could
+  // be a prefix.
+  //
+  // FIXME: This is searching much more than necessary, but I am
+  // blanking on the simplest way to make it fast. We can solve this
+  // problem when we move to TableGen.
+  for (; Start != End; ++Start) {
+    // Scan for first option which is a proper prefix.
+    for (; Start != End; ++Start)
+      if (memcmp(Str, Start->Name, strlen(Start->Name)) == 0)
+        break;
+    if (Start == End)
+      break;
+
+    // See if this option matches.
+    if (Arg *A = getOption(Start - OptionInfos + 1)->accept(Args, Index))
+      return A;
+
+    // Otherwise, see if this argument was missing values.
+    if (Prev != Index)
+      return 0;
+  }
+
+  return new Arg(TheUnknownOption, Index++, Str);
+}
+
+InputArgList *OptTable::ParseArgs(const char* const *ArgBegin,
+                                  const char* const *ArgEnd,
+                                  unsigned &MissingArgIndex,
+                                  unsigned &MissingArgCount) const {
+  InputArgList *Args = new InputArgList(ArgBegin, ArgEnd);
+
+  // FIXME: Handle '@' args (or at least error on them).
+
+  MissingArgIndex = MissingArgCount = 0;
+  unsigned Index = 0, End = ArgEnd - ArgBegin;
+  while (Index < End) {
+    // Ignore empty arguments (other things may still take them as arguments).
+    if (Args->getArgString(Index)[0] == '\0') {
+      ++Index;
+      continue;
+    }
+
+    unsigned Prev = Index;
+    Arg *A = ParseOneArg(*Args, Index);
+    assert(Index > Prev && "Parser failed to consume argument.");
+
+    // Check for missing argument error.
+    if (!A) {
+      assert(Index >= End && "Unexpected parser error.");
+      assert(Index - Prev - 1 && "No missing arguments!");
+      MissingArgIndex = Prev;
+      MissingArgCount = Index - Prev - 1;
+      break;
+    }
+
+    Args->append(A);
+  }
+
+  return Args;
+}
+
+static std::string getOptionHelpName(const OptTable &Opts, OptSpecifier Id) {
+  std::string Name = Opts.getOptionName(Id);
+
+  // Add metavar, if used.
+  switch (Opts.getOptionKind(Id)) {
+  case Option::GroupClass: case Option::InputClass: case Option::UnknownClass:
+    llvm_unreachable("Invalid option with help text.");
+
+  case Option::MultiArgClass:
+    llvm_unreachable("Cannot print metavar for this kind of option.");
+
+  case Option::FlagClass:
+    break;
+
+  case Option::SeparateClass: case Option::JoinedOrSeparateClass:
+    Name += ' ';
+    // FALLTHROUGH
+  case Option::JoinedClass: case Option::CommaJoinedClass:
+  case Option::JoinedAndSeparateClass:
+    if (const char *MetaVarName = Opts.getOptionMetaVar(Id))
+      Name += MetaVarName;
+    else
+      Name += "<value>";
+    break;
+  }
+
+  return Name;
+}
+
+static void PrintHelpOptionList(raw_ostream &OS, StringRef Title,
+                                std::vector<std::pair<std::string,
+                                const char*> > &OptionHelp) {
+  OS << Title << ":\n";
+
+  // Find the maximum option length.
+  unsigned OptionFieldWidth = 0;
+  for (unsigned i = 0, e = OptionHelp.size(); i != e; ++i) {
+    // Skip titles.
+    if (!OptionHelp[i].second)
+      continue;
+
+    // Limit the amount of padding we are willing to give up for alignment.
+    unsigned Length = OptionHelp[i].first.size();
+    if (Length <= 23)
+      OptionFieldWidth = std::max(OptionFieldWidth, Length);
+  }
+
+  const unsigned InitialPad = 2;
+  for (unsigned i = 0, e = OptionHelp.size(); i != e; ++i) {
+    const std::string &Option = OptionHelp[i].first;
+    int Pad = OptionFieldWidth - int(Option.size());
+    OS.indent(InitialPad) << Option;
+
+    // Break on long option names.
+    if (Pad < 0) {
+      OS << "\n";
+      Pad = OptionFieldWidth + InitialPad;
+    }
+    OS.indent(Pad + 1) << OptionHelp[i].second << '\n';
+  }
+}
+
+static const char *getOptionHelpGroup(const OptTable &Opts, OptSpecifier Id) {
+  unsigned GroupID = Opts.getOptionGroupID(Id);
+
+  // If not in a group, return the default help group.
+  if (!GroupID)
+    return "OPTIONS";
+
+  // Abuse the help text of the option groups to store the "help group"
+  // name.
+  //
+  // FIXME: Split out option groups.
+  if (const char *GroupHelp = Opts.getOptionHelpText(GroupID))
+    return GroupHelp;
+
+  // Otherwise keep looking.
+  return getOptionHelpGroup(Opts, GroupID);
+}
+
+void OptTable::PrintHelp(raw_ostream &OS, const char *Name,
+                         const char *Title, bool ShowHidden) const {
+  OS << "OVERVIEW: " << Title << "\n";
+  OS << '\n';
+  OS << "USAGE: " << Name << " [options] <inputs>\n";
+  OS << '\n';
+
+  // Render help text into a map of group-name to a list of (option, help)
+  // pairs.
+  typedef std::map<std::string,
+                 std::vector<std::pair<std::string, const char*> > > helpmap_ty;
+  helpmap_ty GroupedOptionHelp;
+
+  for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
+    unsigned Id = i + 1;
+
+    // FIXME: Split out option groups.
+    if (getOptionKind(Id) == Option::GroupClass)
+      continue;
+
+    if (!ShowHidden && isOptionHelpHidden(Id))
+      continue;
+
+    if (const char *Text = getOptionHelpText(Id)) {
+      const char *HelpGroup = getOptionHelpGroup(*this, Id);
+      const std::string &OptName = getOptionHelpName(*this, Id);
+      GroupedOptionHelp[HelpGroup].push_back(std::make_pair(OptName, Text));
+    }
+  }
+
+  for (helpmap_ty::iterator it = GroupedOptionHelp .begin(),
+         ie = GroupedOptionHelp.end(); it != ie; ++it) {
+    if (it != GroupedOptionHelp .begin())
+      OS << "\n";
+    PrintHelpOptionList(OS, it->first, it->second);
+  }
+
+  OS.flush();
+}
diff --git a/clang/lib/Driver/Option.cpp b/clang/lib/Driver/Option.cpp
new file mode 100644
index 0000000..03360ea
--- /dev/null
+++ b/clang/lib/Driver/Option.cpp
@@ -0,0 +1,280 @@
+//===--- Option.cpp - Abstract Driver Options -----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Option.h"
+
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <cassert>
+#include <algorithm>
+using namespace clang::driver;
+
+Option::Option(OptionClass _Kind, OptSpecifier _ID, const char *_Name,
+               const OptionGroup *_Group, const Option *_Alias)
+  : Kind(_Kind), ID(_ID.getID()), Name(_Name), Group(_Group), Alias(_Alias),
+    Unsupported(false), LinkerInput(false), NoOptAsInput(false),
+    DriverOption(false), NoArgumentUnused(false), NoForward(false) {
+
+  // Multi-level aliases are not supported, and alias options cannot
+  // have groups. This just simplifies option tracking, it is not an
+  // inherent limitation.
+  assert((!Alias || (!Alias->Alias && !Group)) &&
+         "Multi-level aliases and aliases with groups are unsupported.");
+
+  // Initialize rendering options based on the class.
+  switch (Kind) {
+  case GroupClass:
+  case InputClass:
+  case UnknownClass:
+    RenderStyle = RenderValuesStyle;
+    break;
+
+  case JoinedClass:
+  case JoinedAndSeparateClass:
+    RenderStyle = RenderJoinedStyle;
+    break;
+
+  case CommaJoinedClass:
+    RenderStyle = RenderCommaJoinedStyle;
+    break;
+
+  case FlagClass:
+  case SeparateClass:
+  case MultiArgClass:
+  case JoinedOrSeparateClass:
+    RenderStyle = RenderSeparateStyle;
+    break;
+  }
+}
+
+Option::~Option() {
+}
+
+void Option::dump() const {
+  llvm::errs() << "<";
+  switch (Kind) {
+#define P(N) case N: llvm::errs() << #N; break
+    P(GroupClass);
+    P(InputClass);
+    P(UnknownClass);
+    P(FlagClass);
+    P(JoinedClass);
+    P(SeparateClass);
+    P(CommaJoinedClass);
+    P(MultiArgClass);
+    P(JoinedOrSeparateClass);
+    P(JoinedAndSeparateClass);
+#undef P
+  }
+
+  llvm::errs() << " Name:\"" << Name << '"';
+
+  if (Group) {
+    llvm::errs() << " Group:";
+    Group->dump();
+  }
+
+  if (Alias) {
+    llvm::errs() << " Alias:";
+    Alias->dump();
+  }
+
+  if (const MultiArgOption *MOA = dyn_cast<MultiArgOption>(this))
+    llvm::errs() << " NumArgs:" << MOA->getNumArgs();
+
+  llvm::errs() << ">\n";
+}
+
+bool Option::matches(OptSpecifier Opt) const {
+  // Aliases are never considered in matching, look through them.
+  if (Alias)
+    return Alias->matches(Opt);
+
+  // Check exact match.
+  if (ID == Opt)
+    return true;
+
+  if (Group)
+    return Group->matches(Opt);
+  return false;
+}
+
+OptionGroup::OptionGroup(OptSpecifier ID, const char *Name,
+                         const OptionGroup *Group)
+  : Option(Option::GroupClass, ID, Name, Group, 0) {
+}
+
+Arg *OptionGroup::accept(const ArgList &Args, unsigned &Index) const {
+  llvm_unreachable("accept() should never be called on an OptionGroup");
+}
+
+InputOption::InputOption(OptSpecifier ID)
+  : Option(Option::InputClass, ID, "<input>", 0, 0) {
+}
+
+Arg *InputOption::accept(const ArgList &Args, unsigned &Index) const {
+  llvm_unreachable("accept() should never be called on an InputOption");
+}
+
+UnknownOption::UnknownOption(OptSpecifier ID)
+  : Option(Option::UnknownClass, ID, "<unknown>", 0, 0) {
+}
+
+Arg *UnknownOption::accept(const ArgList &Args, unsigned &Index) const {
+  llvm_unreachable("accept() should never be called on an UnknownOption");
+}
+
+FlagOption::FlagOption(OptSpecifier ID, const char *Name,
+                       const OptionGroup *Group, const Option *Alias)
+  : Option(Option::FlagClass, ID, Name, Group, Alias) {
+}
+
+Arg *FlagOption::accept(const ArgList &Args, unsigned &Index) const {
+  // Matches iff this is an exact match.
+  // FIXME: Avoid strlen.
+  if (getName().size() != strlen(Args.getArgString(Index)))
+    return 0;
+
+  return new Arg(getUnaliasedOption(), Index++);
+}
+
+JoinedOption::JoinedOption(OptSpecifier ID, const char *Name,
+                           const OptionGroup *Group, const Option *Alias)
+  : Option(Option::JoinedClass, ID, Name, Group, Alias) {
+}
+
+Arg *JoinedOption::accept(const ArgList &Args, unsigned &Index) const {
+  // Always matches.
+  const char *Value = Args.getArgString(Index) + getName().size();
+  return new Arg(getUnaliasedOption(), Index++, Value);
+}
+
+CommaJoinedOption::CommaJoinedOption(OptSpecifier ID, const char *Name,
+                                     const OptionGroup *Group,
+                                     const Option *Alias)
+  : Option(Option::CommaJoinedClass, ID, Name, Group, Alias) {
+}
+
+Arg *CommaJoinedOption::accept(const ArgList &Args,
+                               unsigned &Index) const {
+  // Always matches.
+  const char *Str = Args.getArgString(Index) + getName().size();
+  Arg *A = new Arg(getUnaliasedOption(), Index++);
+
+  // Parse out the comma separated values.
+  const char *Prev = Str;
+  for (;; ++Str) {
+    char c = *Str;
+
+    if (!c || c == ',') {
+      if (Prev != Str) {
+        char *Value = new char[Str - Prev + 1];
+        memcpy(Value, Prev, Str - Prev);
+        Value[Str - Prev] = '\0';
+        A->getValues().push_back(Value);
+      }
+
+      if (!c)
+        break;
+
+      Prev = Str + 1;
+    }
+  }
+  A->setOwnsValues(true);
+
+  return A;
+}
+
+SeparateOption::SeparateOption(OptSpecifier ID, const char *Name,
+                               const OptionGroup *Group, const Option *Alias)
+  : Option(Option::SeparateClass, ID, Name, Group, Alias) {
+}
+
+Arg *SeparateOption::accept(const ArgList &Args, unsigned &Index) const {
+  // Matches iff this is an exact match.
+  // FIXME: Avoid strlen.
+  if (getName().size() != strlen(Args.getArgString(Index)))
+    return 0;
+
+  Index += 2;
+  if (Index > Args.getNumInputArgStrings())
+    return 0;
+
+  return new Arg(getUnaliasedOption(), Index - 2, Args.getArgString(Index - 1));
+}
+
+MultiArgOption::MultiArgOption(OptSpecifier ID, const char *Name,
+                               const OptionGroup *Group, const Option *Alias,
+                               unsigned _NumArgs)
+  : Option(Option::MultiArgClass, ID, Name, Group, Alias), NumArgs(_NumArgs) {
+  assert(NumArgs > 1  && "Invalid MultiArgOption!");
+}
+
+Arg *MultiArgOption::accept(const ArgList &Args, unsigned &Index) const {
+  // Matches iff this is an exact match.
+  // FIXME: Avoid strlen.
+  if (getName().size() != strlen(Args.getArgString(Index)))
+    return 0;
+
+  Index += 1 + NumArgs;
+  if (Index > Args.getNumInputArgStrings())
+    return 0;
+
+  Arg *A = new Arg(getUnaliasedOption(), Index - 1 - NumArgs,
+                   Args.getArgString(Index - NumArgs));
+  for (unsigned i = 1; i != NumArgs; ++i)
+    A->getValues().push_back(Args.getArgString(Index - NumArgs + i));
+  return A;
+}
+
+JoinedOrSeparateOption::JoinedOrSeparateOption(OptSpecifier ID,
+                                               const char *Name,
+                                               const OptionGroup *Group,
+                                               const Option *Alias)
+  : Option(Option::JoinedOrSeparateClass, ID, Name, Group, Alias) {
+}
+
+Arg *JoinedOrSeparateOption::accept(const ArgList &Args,
+                                    unsigned &Index) const {
+  // If this is not an exact match, it is a joined arg.
+  // FIXME: Avoid strlen.
+  if (getName().size() != strlen(Args.getArgString(Index))) {
+    const char *Value = Args.getArgString(Index) + getName().size();
+    return new Arg(this, Index++, Value);
+  }
+
+  // Otherwise it must be separate.
+  Index += 2;
+  if (Index > Args.getNumInputArgStrings())
+    return 0;
+
+  return new Arg(getUnaliasedOption(), Index - 2, Args.getArgString(Index - 1));
+}
+
+JoinedAndSeparateOption::JoinedAndSeparateOption(OptSpecifier ID,
+                                                 const char *Name,
+                                                 const OptionGroup *Group,
+                                                 const Option *Alias)
+  : Option(Option::JoinedAndSeparateClass, ID, Name, Group, Alias) {
+}
+
+Arg *JoinedAndSeparateOption::accept(const ArgList &Args,
+                                     unsigned &Index) const {
+  // Always matches.
+
+  Index += 2;
+  if (Index > Args.getNumInputArgStrings())
+    return 0;
+
+  return new Arg(getUnaliasedOption(), Index - 2,
+                 Args.getArgString(Index-2)+getName().size(),
+                 Args.getArgString(Index-1));
+}
diff --git a/clang/lib/Driver/Phases.cpp b/clang/lib/Driver/Phases.cpp
new file mode 100644
index 0000000..b885eee
--- /dev/null
+++ b/clang/lib/Driver/Phases.cpp
@@ -0,0 +1,27 @@
+//===--- Phases.cpp - Transformations on Driver Types ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Phases.h"
+#include "llvm/Support/ErrorHandling.h"
+
+#include <cassert>
+
+using namespace clang::driver;
+
+const char *phases::getPhaseName(ID Id) {
+  switch (Id) {
+  case Preprocess: return "preprocessor";
+  case Precompile: return "precompiler";
+  case Compile: return "compiler";
+  case Assemble: return "assembler";
+  case Link: return "linker";
+  }
+
+  llvm_unreachable("Invalid phase id.");
+}
diff --git a/clang/lib/Driver/Tool.cpp b/clang/lib/Driver/Tool.cpp
new file mode 100644
index 0000000..b93864f
--- /dev/null
+++ b/clang/lib/Driver/Tool.cpp
@@ -0,0 +1,21 @@
+//===--- Tool.cpp - Compilation Tools -------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Tool.h"
+
+using namespace clang::driver;
+
+Tool::Tool(const char *_Name, const char *_ShortName,
+           const ToolChain &TC) : Name(_Name), ShortName(_ShortName),
+                                  TheToolChain(TC)
+{
+}
+
+Tool::~Tool() {
+}
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
new file mode 100644
index 0000000..db4d2a8
--- /dev/null
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -0,0 +1,288 @@
+//===--- ToolChain.cpp - Collections of tools for one platform ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/ToolChain.h"
+
+#include "clang/Driver/Action.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/ObjCRuntime.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/ErrorHandling.h"
+using namespace clang::driver;
+using namespace clang;
+
+ToolChain::ToolChain(const Driver &D, const llvm::Triple &T)
+  : D(D), Triple(T) {
+}
+
+ToolChain::~ToolChain() {
+}
+
+const Driver &ToolChain::getDriver() const {
+ return D;
+}
+
+std::string ToolChain::GetFilePath(const char *Name) const {
+  return D.GetFilePath(Name, *this);
+
+}
+
+std::string ToolChain::GetProgramPath(const char *Name, bool WantFile) const {
+  return D.GetProgramPath(Name, *this, WantFile);
+}
+
+types::ID ToolChain::LookupTypeForExtension(const char *Ext) const {
+  return types::lookupTypeForExtension(Ext);
+}
+
+bool ToolChain::HasNativeLLVMSupport() const {
+  return false;
+}
+
+void ToolChain::configureObjCRuntime(ObjCRuntime &runtime) const {
+  switch (runtime.getKind()) {
+  case ObjCRuntime::NeXT:
+    // Assume a minimal NeXT runtime.
+    runtime.HasARC = false;
+    runtime.HasWeak = false;
+    runtime.HasSubscripting = false;
+    runtime.HasTerminate = false;
+    return;
+
+  case ObjCRuntime::GNU:
+    // Assume a maximal GNU runtime.
+    runtime.HasARC = true;
+    runtime.HasWeak = true;
+    runtime.HasSubscripting = false; // to be added
+    runtime.HasTerminate = false; // to be added
+    return;
+  }
+  llvm_unreachable("invalid runtime kind!");
+}
+
+/// getARMTargetCPU - Get the (LLVM) name of the ARM cpu we are targeting.
+//
+// FIXME: tblgen this.
+static const char *getARMTargetCPU(const ArgList &Args,
+                                   const llvm::Triple &Triple) {
+  // For Darwin targets, the -arch option (which is translated to a
+  // corresponding -march option) should determine the architecture
+  // (and the Mach-O slice) regardless of any -mcpu options.
+  if (!Triple.isOSDarwin()) {
+    // FIXME: Warn on inconsistent use of -mcpu and -march.
+    // If we have -mcpu=, use that.
+    if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
+      return A->getValue(Args);
+  }
+
+  StringRef MArch;
+  if (Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+    // Otherwise, if we have -march= choose the base CPU for that arch.
+    MArch = A->getValue(Args);
+  } else {
+    // Otherwise, use the Arch from the triple.
+    MArch = Triple.getArchName();
+  }
+
+  return llvm::StringSwitch<const char *>(MArch)
+    .Cases("armv2", "armv2a","arm2")
+    .Case("armv3", "arm6")
+    .Case("armv3m", "arm7m")
+    .Cases("armv4", "armv4t", "arm7tdmi")
+    .Cases("armv5", "armv5t", "arm10tdmi")
+    .Cases("armv5e", "armv5te", "arm1026ejs")
+    .Case("armv5tej", "arm926ej-s")
+    .Cases("armv6", "armv6k", "arm1136jf-s")
+    .Case("armv6j", "arm1136j-s")
+    .Cases("armv6z", "armv6zk", "arm1176jzf-s")
+    .Case("armv6t2", "arm1156t2-s")
+    .Cases("armv7", "armv7a", "armv7-a", "cortex-a8")
+    .Cases("armv7r", "armv7-r", "cortex-r4")
+    .Cases("armv7m", "armv7-m", "cortex-m3")
+    .Case("ep9312", "ep9312")
+    .Case("iwmmxt", "iwmmxt")
+    .Case("xscale", "xscale")
+    .Cases("armv6m", "armv6-m", "cortex-m0")
+    // If all else failed, return the most base CPU LLVM supports.
+    .Default("arm7tdmi");
+}
+
+/// getLLVMArchSuffixForARM - Get the LLVM arch name to use for a particular
+/// CPU.
+//
+// FIXME: This is redundant with -mcpu, why does LLVM use this.
+// FIXME: tblgen this, or kill it!
+static const char *getLLVMArchSuffixForARM(StringRef CPU) {
+  return llvm::StringSwitch<const char *>(CPU)
+    .Cases("arm7tdmi", "arm7tdmi-s", "arm710t", "v4t")
+    .Cases("arm720t", "arm9", "arm9tdmi", "v4t")
+    .Cases("arm920", "arm920t", "arm922t", "v4t")
+    .Cases("arm940t", "ep9312","v4t")
+    .Cases("arm10tdmi",  "arm1020t", "v5")
+    .Cases("arm9e",  "arm926ej-s",  "arm946e-s", "v5e")
+    .Cases("arm966e-s",  "arm968e-s",  "arm10e", "v5e")
+    .Cases("arm1020e",  "arm1022e",  "xscale", "iwmmxt", "v5e")
+    .Cases("arm1136j-s",  "arm1136jf-s",  "arm1176jz-s", "v6")
+    .Cases("arm1176jzf-s",  "mpcorenovfp",  "mpcore", "v6")
+    .Cases("arm1156t2-s",  "arm1156t2f-s", "v6t2")
+    .Cases("cortex-a8", "cortex-a9", "v7")
+    .Case("cortex-m3", "v7m")
+    .Case("cortex-m4", "v7m")
+    .Case("cortex-m0", "v6m")
+    .Default("");
+}
+
+std::string ToolChain::ComputeLLVMTriple(const ArgList &Args, 
+                                         types::ID InputType) const {
+  switch (getTriple().getArch()) {
+  default:
+    return getTripleString();
+
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb: {
+    // FIXME: Factor into subclasses.
+    llvm::Triple Triple = getTriple();
+
+    // Thumb2 is the default for V7 on Darwin.
+    //
+    // FIXME: Thumb should just be another -target-feaure, not in the triple.
+    StringRef Suffix =
+      getLLVMArchSuffixForARM(getARMTargetCPU(Args, Triple));
+    bool ThumbDefault = (Suffix == "v7" && getTriple().isOSDarwin());
+    std::string ArchName = "arm";
+
+    // Assembly files should start in ARM mode.
+    if (InputType != types::TY_PP_Asm &&
+        Args.hasFlag(options::OPT_mthumb, options::OPT_mno_thumb, ThumbDefault))
+      ArchName = "thumb";
+    Triple.setArchName(ArchName + Suffix.str());
+
+    return Triple.getTriple();
+  }
+  }
+}
+
+std::string ToolChain::ComputeEffectiveClangTriple(const ArgList &Args, 
+                                                   types::ID InputType) const {
+  // Diagnose use of Darwin OS deployment target arguments on non-Darwin.
+  if (Arg *A = Args.getLastArg(options::OPT_mmacosx_version_min_EQ,
+                               options::OPT_miphoneos_version_min_EQ,
+                               options::OPT_mios_simulator_version_min_EQ))
+    getDriver().Diag(diag::err_drv_clang_unsupported)
+      << A->getAsString(Args);
+
+  return ComputeLLVMTriple(Args, InputType);
+}
+
+void ToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                          ArgStringList &CC1Args) const {
+  // Each toolchain should provide the appropriate include flags.
+}
+
+ToolChain::RuntimeLibType ToolChain::GetRuntimeLibType(
+  const ArgList &Args) const
+{
+  if (Arg *A = Args.getLastArg(options::OPT_rtlib_EQ)) {
+    StringRef Value = A->getValue(Args);
+    if (Value == "compiler-rt")
+      return ToolChain::RLT_CompilerRT;
+    if (Value == "libgcc")
+      return ToolChain::RLT_Libgcc;
+    getDriver().Diag(diag::err_drv_invalid_rtlib_name)
+      << A->getAsString(Args);
+  }
+
+  return GetDefaultRuntimeLibType();
+}
+
+ToolChain::CXXStdlibType ToolChain::GetCXXStdlibType(const ArgList &Args) const{
+  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
+    StringRef Value = A->getValue(Args);
+    if (Value == "libc++")
+      return ToolChain::CST_Libcxx;
+    if (Value == "libstdc++")
+      return ToolChain::CST_Libstdcxx;
+    getDriver().Diag(diag::err_drv_invalid_stdlib_name)
+      << A->getAsString(Args);
+  }
+
+  return ToolChain::CST_Libstdcxx;
+}
+
+/// \brief Utility function to add a system include directory to CC1 arguments.
+/*static*/ void ToolChain::addSystemInclude(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args,
+                                            const Twine &Path) {
+  CC1Args.push_back("-internal-isystem");
+  CC1Args.push_back(DriverArgs.MakeArgString(Path));
+}
+
+/// \brief Utility function to add a system include directory with extern "C"
+/// semantics to CC1 arguments.
+///
+/// Note that this should be used rarely, and only for directories that
+/// historically and for legacy reasons are treated as having implicit extern
+/// "C" semantics. These semantics are *ignored* by and large today, but its
+/// important to preserve the preprocessor changes resulting from the
+/// classification.
+/*static*/ void ToolChain::addExternCSystemInclude(const ArgList &DriverArgs,
+                                                   ArgStringList &CC1Args,
+                                                   const Twine &Path) {
+  CC1Args.push_back("-internal-externc-isystem");
+  CC1Args.push_back(DriverArgs.MakeArgString(Path));
+}
+
+/// \brief Utility function to add a list of system include directories to CC1.
+/*static*/ void ToolChain::addSystemIncludes(const ArgList &DriverArgs,
+                                             ArgStringList &CC1Args,
+                                             ArrayRef<StringRef> Paths) {
+  for (ArrayRef<StringRef>::iterator I = Paths.begin(), E = Paths.end();
+       I != E; ++I) {
+    CC1Args.push_back("-internal-isystem");
+    CC1Args.push_back(DriverArgs.MakeArgString(*I));
+  }
+}
+
+void ToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                             ArgStringList &CC1Args) const {
+  // Header search paths should be handled by each of the subclasses.
+  // Historically, they have not been, and instead have been handled inside of
+  // the CC1-layer frontend. As the logic is hoisted out, this generic function
+  // will slowly stop being called.
+  //
+  // While it is being called, replicate a bit of a hack to propagate the
+  // '-stdlib=' flag down to CC1 so that it can in turn customize the C++
+  // header search paths with it. Once all systems are overriding this
+  // function, the CC1 flag and this line can be removed.
+  DriverArgs.AddAllArgs(CC1Args, options::OPT_stdlib_EQ);
+}
+
+void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
+                                    ArgStringList &CmdArgs) const {
+  CXXStdlibType Type = GetCXXStdlibType(Args);
+
+  switch (Type) {
+  case ToolChain::CST_Libcxx:
+    CmdArgs.push_back("-lc++");
+    break;
+
+  case ToolChain::CST_Libstdcxx:
+    CmdArgs.push_back("-lstdc++");
+    break;
+  }
+}
+
+void ToolChain::AddCCKextLibArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-lcc_kext");
+}
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
new file mode 100644
index 0000000..7f9ed9a
--- /dev/null
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -0,0 +1,2334 @@
+//===--- ToolChains.cpp - ToolChain Implementations -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ToolChains.h"
+
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/ObjCRuntime.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/Options.h"
+#include "clang/Basic/Version.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/system_error.h"
+
+#include <cstdlib> // ::getenv
+
+#include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang;
+
+/// Darwin - Darwin tool chain for i386 and x86_64.
+
+Darwin::Darwin(const Driver &D, const llvm::Triple& Triple)
+  : ToolChain(D, Triple), TargetInitialized(false),
+    ARCRuntimeForSimulator(ARCSimulator_None),
+    LibCXXForSimulator(LibCXXSimulator_None)
+{
+  // Compute the initial Darwin version from the triple
+  unsigned Major, Minor, Micro;
+  if (!Triple.getMacOSXVersion(Major, Minor, Micro))
+    getDriver().Diag(diag::err_drv_invalid_darwin_version) <<
+      Triple.getOSName();
+  llvm::raw_string_ostream(MacosxVersionMin)
+    << Major << '.' << Minor << '.' << Micro;
+
+  // FIXME: DarwinVersion is only used to find GCC's libexec directory.
+  // It should be removed when we stop supporting that.
+  DarwinVersion[0] = Minor + 4;
+  DarwinVersion[1] = Micro;
+  DarwinVersion[2] = 0;
+}
+
+types::ID Darwin::LookupTypeForExtension(const char *Ext) const {
+  types::ID Ty = types::lookupTypeForExtension(Ext);
+
+  // Darwin always preprocesses assembly files (unless -x is used explicitly).
+  if (Ty == types::TY_PP_Asm)
+    return types::TY_Asm;
+
+  return Ty;
+}
+
+bool Darwin::HasNativeLLVMSupport() const {
+  return true;
+}
+
+bool Darwin::hasARCRuntime() const {
+  // FIXME: Remove this once there is a proper way to detect an ARC runtime
+  // for the simulator.
+  switch (ARCRuntimeForSimulator) {
+  case ARCSimulator_None:
+    break;
+  case ARCSimulator_HasARCRuntime:
+    return true;
+  case ARCSimulator_NoARCRuntime:
+    return false;
+  }
+
+  if (isTargetIPhoneOS())
+    return !isIPhoneOSVersionLT(5);
+  else
+    return !isMacosxVersionLT(10, 7);
+}
+
+bool Darwin::hasSubscriptingRuntime() const {
+    return !isTargetIPhoneOS() && !isMacosxVersionLT(10, 8);
+}
+
+/// Darwin provides an ARC runtime starting in MacOS X 10.7 and iOS 5.0.
+void Darwin::configureObjCRuntime(ObjCRuntime &runtime) const {
+  if (runtime.getKind() != ObjCRuntime::NeXT)
+    return ToolChain::configureObjCRuntime(runtime);
+
+  runtime.HasARC = runtime.HasWeak = hasARCRuntime();
+  runtime.HasSubscripting = hasSubscriptingRuntime();
+
+  // So far, objc_terminate is only available in iOS 5.
+  // FIXME: do the simulator logic properly.
+  if (!ARCRuntimeForSimulator && isTargetIPhoneOS())
+    runtime.HasTerminate = !isIPhoneOSVersionLT(5);
+  else
+    runtime.HasTerminate = false;
+}
+
+/// Darwin provides a blocks runtime starting in MacOS X 10.6 and iOS 3.2.
+bool Darwin::hasBlocksRuntime() const {
+  if (isTargetIPhoneOS())
+    return !isIPhoneOSVersionLT(3, 2);
+  else
+    return !isMacosxVersionLT(10, 6);
+}
+
+static const char *GetArmArchForMArch(StringRef Value) {
+  return llvm::StringSwitch<const char*>(Value)
+    .Case("armv6k", "armv6")
+    .Case("armv5tej", "armv5")
+    .Case("xscale", "xscale")
+    .Case("armv4t", "armv4t")
+    .Case("armv7", "armv7")
+    .Cases("armv7a", "armv7-a", "armv7")
+    .Cases("armv7r", "armv7-r", "armv7")
+    .Cases("armv7m", "armv7-m", "armv7")
+    .Default(0);
+}
+
+static const char *GetArmArchForMCpu(StringRef Value) {
+  return llvm::StringSwitch<const char *>(Value)
+    .Cases("arm9e", "arm946e-s", "arm966e-s", "arm968e-s", "arm926ej-s","armv5")
+    .Cases("arm10e", "arm10tdmi", "armv5")
+    .Cases("arm1020t", "arm1020e", "arm1022e", "arm1026ej-s", "armv5")
+    .Case("xscale", "xscale")
+    .Cases("arm1136j-s", "arm1136jf-s", "arm1176jz-s",
+           "arm1176jzf-s", "cortex-m0", "armv6")
+    .Cases("cortex-a8", "cortex-r4", "cortex-m3", "cortex-a9", "armv7")
+    .Default(0);
+}
+
+StringRef Darwin::getDarwinArchName(const ArgList &Args) const {
+  switch (getTriple().getArch()) {
+  default:
+    return getArchName();
+
+  case llvm::Triple::thumb:
+  case llvm::Triple::arm: {
+    if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
+      if (const char *Arch = GetArmArchForMArch(A->getValue(Args)))
+        return Arch;
+
+    if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
+      if (const char *Arch = GetArmArchForMCpu(A->getValue(Args)))
+        return Arch;
+
+    return "arm";
+  }
+  }
+}
+
+Darwin::~Darwin() {
+  // Free tool implementations.
+  for (llvm::DenseMap<unsigned, Tool*>::iterator
+         it = Tools.begin(), ie = Tools.end(); it != ie; ++it)
+    delete it->second;
+}
+
+std::string Darwin::ComputeEffectiveClangTriple(const ArgList &Args,
+                                                types::ID InputType) const {
+  llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
+
+  // If the target isn't initialized (e.g., an unknown Darwin platform, return
+  // the default triple).
+  if (!isTargetInitialized())
+    return Triple.getTriple();
+
+  SmallString<16> Str;
+  Str += isTargetIPhoneOS() ? "ios" : "macosx";
+  Str += getTargetVersion().getAsString();
+  Triple.setOSName(Str);
+
+  return Triple.getTriple();
+}
+
+void Generic_ELF::anchor() {}
+
+Tool &Darwin::SelectTool(const Compilation &C, const JobAction &JA,
+                         const ActionList &Inputs) const {
+  Action::ActionClass Key;
+
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple())) {
+    // Fallback to llvm-gcc for i386 kext compiles, we don't support that ABI.
+    if (Inputs.size() == 1 &&
+        types::isCXX(Inputs[0]->getType()) &&
+        getTriple().isOSDarwin() &&
+        getTriple().getArch() == llvm::Triple::x86 &&
+        (C.getArgs().getLastArg(options::OPT_fapple_kext) ||
+         C.getArgs().getLastArg(options::OPT_mkernel)))
+      Key = JA.getKind();
+    else
+      Key = Action::AnalyzeJobClass;
+  } else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::InputClass:
+    case Action::BindArchClass:
+      llvm_unreachable("Invalid tool kind.");
+    case Action::PreprocessJobClass:
+      T = new tools::darwin::Preprocess(*this); break;
+    case Action::AnalyzeJobClass:
+    case Action::MigrateJobClass:
+      T = new tools::Clang(*this); break;
+    case Action::PrecompileJobClass:
+    case Action::CompileJobClass:
+      T = new tools::darwin::Compile(*this); break;
+    case Action::AssembleJobClass: {
+      if (UseIntegratedAs)
+        T = new tools::ClangAs(*this);
+      else
+        T = new tools::darwin::Assemble(*this);
+      break;
+    }
+    case Action::LinkJobClass:
+      T = new tools::darwin::Link(*this); break;
+    case Action::LipoJobClass:
+      T = new tools::darwin::Lipo(*this); break;
+    case Action::DsymutilJobClass:
+      T = new tools::darwin::Dsymutil(*this); break;
+    case Action::VerifyJobClass:
+      T = new tools::darwin::VerifyDebug(*this); break;
+    }
+  }
+
+  return *T;
+}
+
+
+DarwinClang::DarwinClang(const Driver &D, const llvm::Triple& Triple)
+  : Darwin(D, Triple)
+{
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+
+  // We expect 'as', 'ld', etc. to be adjacent to our install dir.
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+
+  // For fallback, we need to know how to find the GCC cc1 executables, so we
+  // also add the GCC libexec paths. This is legacy code that can be removed
+  // once fallback is no longer useful.
+  AddGCCLibexecPath(DarwinVersion[0]);
+  AddGCCLibexecPath(DarwinVersion[0] - 2);
+  AddGCCLibexecPath(DarwinVersion[0] - 1);
+  AddGCCLibexecPath(DarwinVersion[0] + 1);
+  AddGCCLibexecPath(DarwinVersion[0] + 2);
+}
+
+void DarwinClang::AddGCCLibexecPath(unsigned darwinVersion) {
+  std::string ToolChainDir = "i686-apple-darwin";
+  ToolChainDir += llvm::utostr(darwinVersion);
+  ToolChainDir += "/4.2.1";
+
+  std::string Path = getDriver().Dir;
+  Path += "/../llvm-gcc-4.2/libexec/gcc/";
+  Path += ToolChainDir;
+  getProgramPaths().push_back(Path);
+
+  Path = "/usr/llvm-gcc-4.2/libexec/gcc/";
+  Path += ToolChainDir;
+  getProgramPaths().push_back(Path);
+}
+
+void DarwinClang::AddLinkSearchPathArgs(const ArgList &Args,
+                                       ArgStringList &CmdArgs) const {
+  // The Clang toolchain uses explicit paths for internal libraries.
+
+  // Unfortunately, we still might depend on a few of the libraries that are
+  // only available in the gcc library directory (in particular
+  // libstdc++.dylib). For now, hardcode the path to the known install location.
+  // FIXME: This should get ripped out someday.  However, when building on
+  // 10.6 (darwin10), we're still relying on this to find libstdc++.dylib.
+  llvm::sys::Path P(getDriver().Dir);
+  P.eraseComponent(); // .../usr/bin -> ../usr
+  P.appendComponent("llvm-gcc-4.2");
+  P.appendComponent("lib");
+  P.appendComponent("gcc");
+  switch (getTriple().getArch()) {
+  default:
+    llvm_unreachable("Invalid Darwin arch!");
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+    P.appendComponent("i686-apple-darwin10");
+    break;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    P.appendComponent("arm-apple-darwin10");
+    break;
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+    P.appendComponent("powerpc-apple-darwin10");
+    break;
+  }
+  P.appendComponent("4.2.1");
+
+  // Determine the arch specific GCC subdirectory.
+  const char *ArchSpecificDir = 0;
+  switch (getTriple().getArch()) {
+  default:
+    break;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb: {
+    std::string Triple = ComputeLLVMTriple(Args);
+    StringRef TripleStr = Triple;
+    if (TripleStr.startswith("armv5") || TripleStr.startswith("thumbv5"))
+      ArchSpecificDir = "v5";
+    else if (TripleStr.startswith("armv6") || TripleStr.startswith("thumbv6"))
+      ArchSpecificDir = "v6";
+    else if (TripleStr.startswith("armv7") || TripleStr.startswith("thumbv7"))
+      ArchSpecificDir = "v7";
+    break;
+  }
+  case llvm::Triple::ppc64:
+    ArchSpecificDir = "ppc64";
+    break;
+  case llvm::Triple::x86_64:
+    ArchSpecificDir = "x86_64";
+    break;
+  }
+
+  if (ArchSpecificDir) {
+    P.appendComponent(ArchSpecificDir);
+    bool Exists;
+    if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+      CmdArgs.push_back(Args.MakeArgString("-L" + P.str()));
+    P.eraseComponent();
+  }
+
+  bool Exists;
+  if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+    CmdArgs.push_back(Args.MakeArgString("-L" + P.str()));
+}
+
+void DarwinClang::AddLinkARCArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+
+  CmdArgs.push_back("-force_load");
+  llvm::sys::Path P(getDriver().ClangExecutable);
+  P.eraseComponent(); // 'clang'
+  P.eraseComponent(); // 'bin'
+  P.appendComponent("lib");
+  P.appendComponent("arc");
+  P.appendComponent("libarclite_");
+  std::string s = P.str();
+  // Mash in the platform.
+  if (isTargetIOSSimulator())
+    s += "iphonesimulator";
+  else if (isTargetIPhoneOS())
+    s += "iphoneos";
+  // FIXME: Remove this once we depend fully on -mios-simulator-version-min.
+  else if (ARCRuntimeForSimulator != ARCSimulator_None)
+    s += "iphonesimulator";
+  else
+    s += "macosx";
+  s += ".a";
+
+  CmdArgs.push_back(Args.MakeArgString(s));
+}
+
+void DarwinClang::AddLinkRuntimeLib(const ArgList &Args,
+                                    ArgStringList &CmdArgs,
+                                    const char *DarwinStaticLib) const {
+  llvm::sys::Path P(getDriver().ResourceDir);
+  P.appendComponent("lib");
+  P.appendComponent("darwin");
+  P.appendComponent(DarwinStaticLib);
+
+  // For now, allow missing resource libraries to support developers who may
+  // not have compiler-rt checked out or integrated into their build.
+  bool Exists;
+  if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+    CmdArgs.push_back(Args.MakeArgString(P.str()));
+}
+
+void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
+                                        ArgStringList &CmdArgs) const {
+  // Darwin only supports the compiler-rt based runtime libraries.
+  switch (GetRuntimeLibType(Args)) {
+  case ToolChain::RLT_CompilerRT:
+    break;
+  default:
+    getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
+      << Args.getLastArg(options::OPT_rtlib_EQ)->getValue(Args) << "darwin";
+    return;
+  }
+
+  // Darwin doesn't support real static executables, don't link any runtime
+  // libraries with -static.
+  if (Args.hasArg(options::OPT_static))
+    return;
+
+  // Reject -static-libgcc for now, we can deal with this when and if someone
+  // cares. This is useful in situations where someone wants to statically link
+  // something like libstdc++, and needs its runtime support routines.
+  if (const Arg *A = Args.getLastArg(options::OPT_static_libgcc)) {
+    getDriver().Diag(diag::err_drv_unsupported_opt)
+      << A->getAsString(Args);
+    return;
+  }
+
+  // If we are building profile support, link that library in.
+  if (Args.hasArg(options::OPT_fprofile_arcs) ||
+      Args.hasArg(options::OPT_fprofile_generate) ||
+      Args.hasArg(options::OPT_fcreate_profile) ||
+      Args.hasArg(options::OPT_coverage)) {
+    // Select the appropriate runtime library for the target.
+    if (isTargetIPhoneOS()) {
+      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.profile_ios.a");
+    } else {
+      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.profile_osx.a");
+    }
+  }
+
+  // Add ASAN runtime library, if required. Dynamic libraries and bundles
+  // should not be linked with the runtime library.
+  if (Args.hasFlag(options::OPT_faddress_sanitizer,
+                   options::OPT_fno_address_sanitizer, false)) {
+    if (Args.hasArg(options::OPT_dynamiclib) ||
+        Args.hasArg(options::OPT_bundle)) return;
+    if (isTargetIPhoneOS()) {
+      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform)
+        << "-faddress-sanitizer";
+    } else {
+      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.asan_osx.a");
+
+      // The ASAN runtime library requires C++ and CoreFoundation.
+      AddCXXStdlibLibArgs(Args, CmdArgs);
+      CmdArgs.push_back("-framework");
+      CmdArgs.push_back("CoreFoundation");
+    }
+  }
+
+  // Otherwise link libSystem, then the dynamic runtime library, and finally any
+  // target specific static runtime library.
+  CmdArgs.push_back("-lSystem");
+
+  // Select the dynamic runtime library and the target specific static library.
+  if (isTargetIPhoneOS()) {
+    // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,
+    // it never went into the SDK.
+    // Linking against libgcc_s.1 isn't needed for iOS 5.0+
+    if (isIPhoneOSVersionLT(5, 0) && !isTargetIOSSimulator())
+      CmdArgs.push_back("-lgcc_s.1");
+
+    // We currently always need a static runtime library for iOS.
+    AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.ios.a");
+  } else {
+    // The dynamic runtime library was merged with libSystem for 10.6 and
+    // beyond; only 10.4 and 10.5 need an additional runtime library.
+    if (isMacosxVersionLT(10, 5))
+      CmdArgs.push_back("-lgcc_s.10.4");
+    else if (isMacosxVersionLT(10, 6))
+      CmdArgs.push_back("-lgcc_s.10.5");
+
+    // For OS X, we thought we would only need a static runtime library when
+    // targeting 10.4, to provide versions of the static functions which were
+    // omitted from 10.4.dylib.
+    //
+    // Unfortunately, that turned out to not be true, because Darwin system
+    // headers can still use eprintf on i386, and it is not exported from
+    // libSystem. Therefore, we still must provide a runtime library just for
+    // the tiny tiny handful of projects that *might* use that symbol.
+    if (isMacosxVersionLT(10, 5)) {
+      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.10.4.a");
+    } else {
+      if (getTriple().getArch() == llvm::Triple::x86)
+        AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.eprintf.a");
+      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.osx.a");
+    }
+  }
+}
+
+static inline StringRef SimulatorVersionDefineName() {
+  return "__IPHONE_OS_VERSION_MIN_REQUIRED";
+}
+
+/// \brief Parse the simulator version define:
+/// __IPHONE_OS_VERSION_MIN_REQUIRED=([0-9])([0-9][0-9])([0-9][0-9])
+// and return the grouped values as integers, e.g:
+//   __IPHONE_OS_VERSION_MIN_REQUIRED=40201
+// will return Major=4, Minor=2, Micro=1.
+static bool GetVersionFromSimulatorDefine(StringRef define,
+                                          unsigned &Major, unsigned &Minor,
+                                          unsigned &Micro) {
+  assert(define.startswith(SimulatorVersionDefineName()));
+  StringRef name, version;
+  llvm::tie(name, version) = define.split('=');
+  if (version.empty())
+    return false;
+  std::string verstr = version.str();
+  char *end;
+  unsigned num = (unsigned) strtol(verstr.c_str(), &end, 10);
+  if (*end != '\0')
+    return false;
+  Major = num / 10000;
+  num = num % 10000;
+  Minor = num / 100;
+  Micro = num % 100;
+  return true;
+}
+
+void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
+  const OptTable &Opts = getDriver().getOpts();
+
+  Arg *OSXVersion = Args.getLastArg(options::OPT_mmacosx_version_min_EQ);
+  Arg *iOSVersion = Args.getLastArg(options::OPT_miphoneos_version_min_EQ);
+  Arg *iOSSimVersion = Args.getLastArg(
+    options::OPT_mios_simulator_version_min_EQ);
+
+  // FIXME: HACK! When compiling for the simulator we don't get a
+  // '-miphoneos-version-min' to help us know whether there is an ARC runtime
+  // or not; try to parse a __IPHONE_OS_VERSION_MIN_REQUIRED
+  // define passed in command-line.
+  if (!iOSVersion && !iOSSimVersion) {
+    for (arg_iterator it = Args.filtered_begin(options::OPT_D),
+           ie = Args.filtered_end(); it != ie; ++it) {
+      StringRef define = (*it)->getValue(Args);
+      if (define.startswith(SimulatorVersionDefineName())) {
+        unsigned Major = 0, Minor = 0, Micro = 0;
+        if (GetVersionFromSimulatorDefine(define, Major, Minor, Micro) &&
+            Major < 10 && Minor < 100 && Micro < 100) {
+          ARCRuntimeForSimulator = Major < 5 ? ARCSimulator_NoARCRuntime
+                                             : ARCSimulator_HasARCRuntime;
+          LibCXXForSimulator = Major < 5 ? LibCXXSimulator_NotAvailable
+                                         : LibCXXSimulator_Available;
+        }
+        break;
+      }
+    }
+  }
+
+  if (OSXVersion && (iOSVersion || iOSSimVersion)) {
+    getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << OSXVersion->getAsString(Args)
+          << (iOSVersion ? iOSVersion : iOSSimVersion)->getAsString(Args);
+    iOSVersion = iOSSimVersion = 0;
+  } else if (iOSVersion && iOSSimVersion) {
+    getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << iOSVersion->getAsString(Args)
+          << iOSSimVersion->getAsString(Args);
+    iOSSimVersion = 0;
+  } else if (!OSXVersion && !iOSVersion && !iOSSimVersion) {
+    // If no deployment target was specified on the command line, check for
+    // environment defines.
+    StringRef OSXTarget;
+    StringRef iOSTarget;
+    StringRef iOSSimTarget;
+    if (char *env = ::getenv("MACOSX_DEPLOYMENT_TARGET"))
+      OSXTarget = env;
+    if (char *env = ::getenv("IPHONEOS_DEPLOYMENT_TARGET"))
+      iOSTarget = env;
+    if (char *env = ::getenv("IOS_SIMULATOR_DEPLOYMENT_TARGET"))
+      iOSSimTarget = env;
+
+    // If no '-miphoneos-version-min' specified on the command line and
+    // IPHONEOS_DEPLOYMENT_TARGET is not defined, see if we can set the default
+    // based on -isysroot.
+    if (iOSTarget.empty()) {
+      if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
+        StringRef first, second;
+        StringRef isysroot = A->getValue(Args);
+        llvm::tie(first, second) = isysroot.split(StringRef("SDKs/iPhoneOS"));
+        if (second != "")
+          iOSTarget = second.substr(0,3);
+      }
+    }
+
+    // If no OSX or iOS target has been specified and we're compiling for armv7,
+    // go ahead as assume we're targeting iOS.
+    if (OSXTarget.empty() && iOSTarget.empty())
+      if (getDarwinArchName(Args) == "armv7")
+        iOSTarget = "0.0";
+
+    // Handle conflicting deployment targets
+    //
+    // FIXME: Don't hardcode default here.
+
+    // Do not allow conflicts with the iOS simulator target.
+    if (!iOSSimTarget.empty() && (!OSXTarget.empty() || !iOSTarget.empty())) {
+      getDriver().Diag(diag::err_drv_conflicting_deployment_targets)
+        << "IOS_SIMULATOR_DEPLOYMENT_TARGET"
+        << (!OSXTarget.empty() ? "MACOSX_DEPLOYMENT_TARGET" :
+            "IPHONEOS_DEPLOYMENT_TARGET");
+    }
+
+    // Allow conflicts among OSX and iOS for historical reasons, but choose the
+    // default platform.
+    if (!OSXTarget.empty() && !iOSTarget.empty()) {
+      if (getTriple().getArch() == llvm::Triple::arm ||
+          getTriple().getArch() == llvm::Triple::thumb)
+        OSXTarget = "";
+      else
+        iOSTarget = "";
+    }
+
+    if (!OSXTarget.empty()) {
+      const Option *O = Opts.getOption(options::OPT_mmacosx_version_min_EQ);
+      OSXVersion = Args.MakeJoinedArg(0, O, OSXTarget);
+      Args.append(OSXVersion);
+    } else if (!iOSTarget.empty()) {
+      const Option *O = Opts.getOption(options::OPT_miphoneos_version_min_EQ);
+      iOSVersion = Args.MakeJoinedArg(0, O, iOSTarget);
+      Args.append(iOSVersion);
+    } else if (!iOSSimTarget.empty()) {
+      const Option *O = Opts.getOption(
+        options::OPT_mios_simulator_version_min_EQ);
+      iOSSimVersion = Args.MakeJoinedArg(0, O, iOSSimTarget);
+      Args.append(iOSSimVersion);
+    } else {
+      // Otherwise, assume we are targeting OS X.
+      const Option *O = Opts.getOption(options::OPT_mmacosx_version_min_EQ);
+      OSXVersion = Args.MakeJoinedArg(0, O, MacosxVersionMin);
+      Args.append(OSXVersion);
+    }
+  }
+
+  // Reject invalid architecture combinations.
+  if (iOSSimVersion && (getTriple().getArch() != llvm::Triple::x86 &&
+                        getTriple().getArch() != llvm::Triple::x86_64)) {
+    getDriver().Diag(diag::err_drv_invalid_arch_for_deployment_target)
+      << getTriple().getArchName() << iOSSimVersion->getAsString(Args);
+  }
+
+  // Set the tool chain target information.
+  unsigned Major, Minor, Micro;
+  bool HadExtra;
+  if (OSXVersion) {
+    assert((!iOSVersion && !iOSSimVersion) && "Unknown target platform!");
+    if (!Driver::GetReleaseVersion(OSXVersion->getValue(Args), Major, Minor,
+                                   Micro, HadExtra) || HadExtra ||
+        Major != 10 || Minor >= 100 || Micro >= 100)
+      getDriver().Diag(diag::err_drv_invalid_version_number)
+        << OSXVersion->getAsString(Args);
+  } else {
+    const Arg *Version = iOSVersion ? iOSVersion : iOSSimVersion;
+    assert(Version && "Unknown target platform!");
+    if (!Driver::GetReleaseVersion(Version->getValue(Args), Major, Minor,
+                                   Micro, HadExtra) || HadExtra ||
+        Major >= 10 || Minor >= 100 || Micro >= 100)
+      getDriver().Diag(diag::err_drv_invalid_version_number)
+        << Version->getAsString(Args);
+  }
+
+  bool IsIOSSim = bool(iOSSimVersion);
+
+  // In GCC, the simulator historically was treated as being OS X in some
+  // contexts, like determining the link logic, despite generally being called
+  // with an iOS deployment target. For compatibility, we detect the
+  // simulator as iOS + x86, and treat it differently in a few contexts.
+  if (iOSVersion && (getTriple().getArch() == llvm::Triple::x86 ||
+                     getTriple().getArch() == llvm::Triple::x86_64))
+    IsIOSSim = true;
+
+  setTarget(/*IsIPhoneOS=*/ !OSXVersion, Major, Minor, Micro, IsIOSSim);
+}
+
+void DarwinClang::AddCXXStdlibLibArgs(const ArgList &Args,
+                                      ArgStringList &CmdArgs) const {
+  CXXStdlibType Type = GetCXXStdlibType(Args);
+
+  switch (Type) {
+  case ToolChain::CST_Libcxx:
+    CmdArgs.push_back("-lc++");
+    break;
+
+  case ToolChain::CST_Libstdcxx: {
+    // Unfortunately, -lstdc++ doesn't always exist in the standard search path;
+    // it was previously found in the gcc lib dir. However, for all the Darwin
+    // platforms we care about it was -lstdc++.6, so we search for that
+    // explicitly if we can't see an obvious -lstdc++ candidate.
+
+    // Check in the sysroot first.
+    bool Exists;
+    if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
+      llvm::sys::Path P(A->getValue(Args));
+      P.appendComponent("usr");
+      P.appendComponent("lib");
+      P.appendComponent("libstdc++.dylib");
+
+      if (llvm::sys::fs::exists(P.str(), Exists) || !Exists) {
+        P.eraseComponent();
+        P.appendComponent("libstdc++.6.dylib");
+        if (!llvm::sys::fs::exists(P.str(), Exists) && Exists) {
+          CmdArgs.push_back(Args.MakeArgString(P.str()));
+          return;
+        }
+      }
+    }
+
+    // Otherwise, look in the root.
+    // FIXME: This should be removed someday when we don't have to care about
+    // 10.6 and earlier, where /usr/lib/libstdc++.dylib does not exist.
+    if ((llvm::sys::fs::exists("/usr/lib/libstdc++.dylib", Exists) || !Exists)&&
+      (!llvm::sys::fs::exists("/usr/lib/libstdc++.6.dylib", Exists) && Exists)){
+      CmdArgs.push_back("/usr/lib/libstdc++.6.dylib");
+      return;
+    }
+
+    // Otherwise, let the linker search.
+    CmdArgs.push_back("-lstdc++");
+    break;
+  }
+  }
+}
+
+void DarwinClang::AddCCKextLibArgs(const ArgList &Args,
+                                   ArgStringList &CmdArgs) const {
+
+  // For Darwin platforms, use the compiler-rt-based support library
+  // instead of the gcc-provided one (which is also incidentally
+  // only present in the gcc lib dir, which makes it hard to find).
+
+  llvm::sys::Path P(getDriver().ResourceDir);
+  P.appendComponent("lib");
+  P.appendComponent("darwin");
+  P.appendComponent("libclang_rt.cc_kext.a");
+
+  // For now, allow missing resource libraries to support developers who may
+  // not have compiler-rt checked out or integrated into their build.
+  bool Exists;
+  if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+    CmdArgs.push_back(Args.MakeArgString(P.str()));
+}
+
+DerivedArgList *Darwin::TranslateArgs(const DerivedArgList &Args,
+                                      const char *BoundArch) const {
+  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
+  const OptTable &Opts = getDriver().getOpts();
+
+  // FIXME: We really want to get out of the tool chain level argument
+  // translation business, as it makes the driver functionality much
+  // more opaque. For now, we follow gcc closely solely for the
+  // purpose of easily achieving feature parity & testability. Once we
+  // have something that works, we should reevaluate each translation
+  // and try to push it down into tool specific logic.
+
+  for (ArgList::const_iterator it = Args.begin(),
+         ie = Args.end(); it != ie; ++it) {
+    Arg *A = *it;
+
+    if (A->getOption().matches(options::OPT_Xarch__)) {
+      // Skip this argument unless the architecture matches either the toolchain
+      // triple arch, or the arch being bound.
+      //
+      // FIXME: Canonicalize name.
+      StringRef XarchArch = A->getValue(Args, 0);
+      if (!(XarchArch == getArchName()  ||
+            (BoundArch && XarchArch == BoundArch)))
+        continue;
+
+      Arg *OriginalArg = A;
+      unsigned Index = Args.getBaseArgs().MakeIndex(A->getValue(Args, 1));
+      unsigned Prev = Index;
+      Arg *XarchArg = Opts.ParseOneArg(Args, Index);
+
+      // If the argument parsing failed or more than one argument was
+      // consumed, the -Xarch_ argument's parameter tried to consume
+      // extra arguments. Emit an error and ignore.
+      //
+      // We also want to disallow any options which would alter the
+      // driver behavior; that isn't going to work in our model. We
+      // use isDriverOption() as an approximation, although things
+      // like -O4 are going to slip through.
+      if (!XarchArg || Index > Prev + 1) {
+        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_with_args)
+          << A->getAsString(Args);
+        continue;
+      } else if (XarchArg->getOption().isDriverOption()) {
+        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_isdriver)
+          << A->getAsString(Args);
+        continue;
+      }
+
+      XarchArg->setBaseArg(A);
+      A = XarchArg;
+
+      DAL->AddSynthesizedArg(A);
+
+      // Linker input arguments require custom handling. The problem is that we
+      // have already constructed the phase actions, so we can not treat them as
+      // "input arguments".
+      if (A->getOption().isLinkerInput()) {
+        // Convert the argument into individual Zlinker_input_args.
+        for (unsigned i = 0, e = A->getNumValues(); i != e; ++i) {
+          DAL->AddSeparateArg(OriginalArg,
+                              Opts.getOption(options::OPT_Zlinker_input),
+                              A->getValue(Args, i));
+
+        }
+        continue;
+      }
+    }
+
+    // Sob. These is strictly gcc compatible for the time being. Apple
+    // gcc translates options twice, which means that self-expanding
+    // options add duplicates.
+    switch ((options::ID) A->getOption().getID()) {
+    default:
+      DAL->append(A);
+      break;
+
+    case options::OPT_mkernel:
+    case options::OPT_fapple_kext:
+      DAL->append(A);
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_static));
+      break;
+
+    case options::OPT_dependency_file:
+      DAL->AddSeparateArg(A, Opts.getOption(options::OPT_MF),
+                          A->getValue(Args));
+      break;
+
+    case options::OPT_gfull:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_g_Flag));
+      DAL->AddFlagArg(A,
+               Opts.getOption(options::OPT_fno_eliminate_unused_debug_symbols));
+      break;
+
+    case options::OPT_gused:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_g_Flag));
+      DAL->AddFlagArg(A,
+             Opts.getOption(options::OPT_feliminate_unused_debug_symbols));
+      break;
+
+    case options::OPT_shared:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_dynamiclib));
+      break;
+
+    case options::OPT_fconstant_cfstrings:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mconstant_cfstrings));
+      break;
+
+    case options::OPT_fno_constant_cfstrings:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mno_constant_cfstrings));
+      break;
+
+    case options::OPT_Wnonportable_cfstrings:
+      DAL->AddFlagArg(A,
+                      Opts.getOption(options::OPT_mwarn_nonportable_cfstrings));
+      break;
+
+    case options::OPT_Wno_nonportable_cfstrings:
+      DAL->AddFlagArg(A,
+                   Opts.getOption(options::OPT_mno_warn_nonportable_cfstrings));
+      break;
+
+    case options::OPT_fpascal_strings:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mpascal_strings));
+      break;
+
+    case options::OPT_fno_pascal_strings:
+      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mno_pascal_strings));
+      break;
+    }
+  }
+
+  if (getTriple().getArch() == llvm::Triple::x86 ||
+      getTriple().getArch() == llvm::Triple::x86_64)
+    if (!Args.hasArgNoClaim(options::OPT_mtune_EQ))
+      DAL->AddJoinedArg(0, Opts.getOption(options::OPT_mtune_EQ), "core2");
+
+  // Add the arch options based on the particular spelling of -arch, to match
+  // how the driver driver works.
+  if (BoundArch) {
+    StringRef Name = BoundArch;
+    const Option *MCpu = Opts.getOption(options::OPT_mcpu_EQ);
+    const Option *MArch = Opts.getOption(options::OPT_march_EQ);
+
+    // This code must be kept in sync with LLVM's getArchTypeForDarwinArch,
+    // which defines the list of which architectures we accept.
+    if (Name == "ppc")
+      ;
+    else if (Name == "ppc601")
+      DAL->AddJoinedArg(0, MCpu, "601");
+    else if (Name == "ppc603")
+      DAL->AddJoinedArg(0, MCpu, "603");
+    else if (Name == "ppc604")
+      DAL->AddJoinedArg(0, MCpu, "604");
+    else if (Name == "ppc604e")
+      DAL->AddJoinedArg(0, MCpu, "604e");
+    else if (Name == "ppc750")
+      DAL->AddJoinedArg(0, MCpu, "750");
+    else if (Name == "ppc7400")
+      DAL->AddJoinedArg(0, MCpu, "7400");
+    else if (Name == "ppc7450")
+      DAL->AddJoinedArg(0, MCpu, "7450");
+    else if (Name == "ppc970")
+      DAL->AddJoinedArg(0, MCpu, "970");
+
+    else if (Name == "ppc64")
+      DAL->AddFlagArg(0, Opts.getOption(options::OPT_m64));
+
+    else if (Name == "i386")
+      ;
+    else if (Name == "i486")
+      DAL->AddJoinedArg(0, MArch, "i486");
+    else if (Name == "i586")
+      DAL->AddJoinedArg(0, MArch, "i586");
+    else if (Name == "i686")
+      DAL->AddJoinedArg(0, MArch, "i686");
+    else if (Name == "pentium")
+      DAL->AddJoinedArg(0, MArch, "pentium");
+    else if (Name == "pentium2")
+      DAL->AddJoinedArg(0, MArch, "pentium2");
+    else if (Name == "pentpro")
+      DAL->AddJoinedArg(0, MArch, "pentiumpro");
+    else if (Name == "pentIIm3")
+      DAL->AddJoinedArg(0, MArch, "pentium2");
+
+    else if (Name == "x86_64")
+      DAL->AddFlagArg(0, Opts.getOption(options::OPT_m64));
+
+    else if (Name == "arm")
+      DAL->AddJoinedArg(0, MArch, "armv4t");
+    else if (Name == "armv4t")
+      DAL->AddJoinedArg(0, MArch, "armv4t");
+    else if (Name == "armv5")
+      DAL->AddJoinedArg(0, MArch, "armv5tej");
+    else if (Name == "xscale")
+      DAL->AddJoinedArg(0, MArch, "xscale");
+    else if (Name == "armv6")
+      DAL->AddJoinedArg(0, MArch, "armv6k");
+    else if (Name == "armv7")
+      DAL->AddJoinedArg(0, MArch, "armv7a");
+
+    else
+      llvm_unreachable("invalid Darwin arch");
+  }
+
+  // Add an explicit version min argument for the deployment target. We do this
+  // after argument translation because -Xarch_ arguments may add a version min
+  // argument.
+  AddDeploymentTarget(*DAL);
+
+  // Validate the C++ standard library choice.
+  CXXStdlibType Type = GetCXXStdlibType(*DAL);
+  if (Type == ToolChain::CST_Libcxx) {
+    switch (LibCXXForSimulator) {
+    case LibCXXSimulator_None:
+      // Handle non-simulator cases.
+      if (isTargetIPhoneOS()) {
+        if (isIPhoneOSVersionLT(5, 0)) {
+          getDriver().Diag(clang::diag::err_drv_invalid_libcxx_deployment)
+            << "iOS 5.0";
+        }
+      }
+      break;
+    case LibCXXSimulator_NotAvailable:
+      getDriver().Diag(clang::diag::err_drv_invalid_libcxx_deployment)
+        << "iOS 5.0";
+      break;
+    case LibCXXSimulator_Available:
+      break;
+    }
+  }
+
+  return DAL;
+}
+
+bool Darwin::IsUnwindTablesDefault() const {
+  // FIXME: Gross; we should probably have some separate target
+  // definition, possibly even reusing the one in clang.
+  return getArchName() == "x86_64";
+}
+
+bool Darwin::UseDwarfDebugFlags() const {
+  if (const char *S = ::getenv("RC_DEBUG_OPTIONS"))
+    return S[0] != '\0';
+  return false;
+}
+
+bool Darwin::UseSjLjExceptions() const {
+  // Darwin uses SjLj exceptions on ARM.
+  return (getTriple().getArch() == llvm::Triple::arm ||
+          getTriple().getArch() == llvm::Triple::thumb);
+}
+
+const char *Darwin::GetDefaultRelocationModel() const {
+  return "pic";
+}
+
+const char *Darwin::GetForcedPicModel() const {
+  if (getArchName() == "x86_64")
+    return "pic";
+  return 0;
+}
+
+bool Darwin::SupportsProfiling() const {
+  // Profiling instrumentation is only supported on x86.
+  return getArchName() == "i386" || getArchName() == "x86_64";
+}
+
+bool Darwin::SupportsObjCGC() const {
+  // Garbage collection is supported everywhere except on iPhone OS.
+  return !isTargetIPhoneOS();
+}
+
+bool Darwin::SupportsObjCARC() const {
+  return isTargetIPhoneOS() || !isMacosxVersionLT(10, 6);
+}
+
+std::string
+Darwin_Generic_GCC::ComputeEffectiveClangTriple(const ArgList &Args,
+                                                types::ID InputType) const {
+  return ComputeLLVMTriple(Args, InputType);
+}
+
+/// Generic_GCC - A tool chain using the 'gcc' command to perform
+/// all subcommands; this relies on gcc translating the majority of
+/// command line options.
+
+/// \brief Parse a GCCVersion object out of a string of text.
+///
+/// This is the primary means of forming GCCVersion objects.
+/*static*/
+Generic_GCC::GCCVersion Linux::GCCVersion::Parse(StringRef VersionText) {
+  const GCCVersion BadVersion = { VersionText.str(), -1, -1, -1, "" };
+  std::pair<StringRef, StringRef> First = VersionText.split('.');
+  std::pair<StringRef, StringRef> Second = First.second.split('.');
+
+  GCCVersion GoodVersion = { VersionText.str(), -1, -1, -1, "" };
+  if (First.first.getAsInteger(10, GoodVersion.Major) ||
+      GoodVersion.Major < 0)
+    return BadVersion;
+  if (Second.first.getAsInteger(10, GoodVersion.Minor) ||
+      GoodVersion.Minor < 0)
+    return BadVersion;
+
+  // First look for a number prefix and parse that if present. Otherwise just
+  // stash the entire patch string in the suffix, and leave the number
+  // unspecified. This covers versions strings such as:
+  //   4.4
+  //   4.4.0
+  //   4.4.x
+  //   4.4.2-rc4
+  //   4.4.x-patched
+  // And retains any patch number it finds.
+  StringRef PatchText = GoodVersion.PatchSuffix = Second.second.str();
+  if (!PatchText.empty()) {
+    if (unsigned EndNumber = PatchText.find_first_not_of("0123456789")) {
+      // Try to parse the number and any suffix.
+      if (PatchText.slice(0, EndNumber).getAsInteger(10, GoodVersion.Patch) ||
+          GoodVersion.Patch < 0)
+        return BadVersion;
+      GoodVersion.PatchSuffix = PatchText.substr(EndNumber).str();
+    }
+  }
+
+  return GoodVersion;
+}
+
+/// \brief Less-than for GCCVersion, implementing a Strict Weak Ordering.
+bool Generic_GCC::GCCVersion::operator<(const GCCVersion &RHS) const {
+  if (Major < RHS.Major) return true; if (Major > RHS.Major) return false;
+  if (Minor < RHS.Minor) return true; if (Minor > RHS.Minor) return false;
+
+  // Note that we rank versions with *no* patch specified is better than ones
+  // hard-coding a patch version. Thus if the RHS has no patch, it always
+  // wins, and the LHS only wins if it has no patch and the RHS does have
+  // a patch.
+  if (RHS.Patch == -1) return true;   if (Patch == -1) return false;
+  if (Patch < RHS.Patch) return true; if (Patch > RHS.Patch) return false;
+  if (PatchSuffix == RHS.PatchSuffix) return false;
+
+  // Finally, between completely tied version numbers, the version with the
+  // suffix loses as we prefer full releases.
+  if (RHS.PatchSuffix.empty()) return true;
+  return false;
+}
+
+static StringRef getGCCToolchainDir(const ArgList &Args) {
+  const Arg *A = Args.getLastArg(options::OPT_gcc_toolchain);
+  if (A)
+    return A->getValue(Args);
+  return GCC_INSTALL_PREFIX;
+}
+
+/// \brief Construct a GCCInstallationDetector from the driver.
+///
+/// This performs all of the autodetection and sets up the various paths.
+/// Once constructed, a GCCInstallationDetector is essentially immutable.
+///
+/// FIXME: We shouldn't need an explicit TargetTriple parameter here, and
+/// should instead pull the target out of the driver. This is currently
+/// necessary because the driver doesn't store the final version of the target
+/// triple.
+Generic_GCC::GCCInstallationDetector::GCCInstallationDetector(
+    const Driver &D,
+    const llvm::Triple &TargetTriple,
+    const ArgList &Args)
+    : IsValid(false) {
+  llvm::Triple MultiarchTriple
+    = TargetTriple.isArch32Bit() ? TargetTriple.get64BitArchVariant()
+                                 : TargetTriple.get32BitArchVariant();
+  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
+  // The library directories which may contain GCC installations.
+  SmallVector<StringRef, 4> CandidateLibDirs, CandidateMultiarchLibDirs;
+  // The compatible GCC triples for this particular architecture.
+  SmallVector<StringRef, 10> CandidateTripleAliases;
+  SmallVector<StringRef, 10> CandidateMultiarchTripleAliases;
+  CollectLibDirsAndTriples(TargetTriple, MultiarchTriple, CandidateLibDirs,
+                           CandidateTripleAliases,
+                           CandidateMultiarchLibDirs,
+                           CandidateMultiarchTripleAliases);
+
+  // Compute the set of prefixes for our search.
+  SmallVector<std::string, 8> Prefixes(D.PrefixDirs.begin(),
+                                       D.PrefixDirs.end());
+
+  StringRef GCCToolchainDir = getGCCToolchainDir(Args);
+  if (GCCToolchainDir != "") {
+    if (GCCToolchainDir.back() == '/')
+      GCCToolchainDir = GCCToolchainDir.drop_back(); // remove the /
+
+    Prefixes.push_back(GCCToolchainDir);
+  } else {
+    Prefixes.push_back(D.SysRoot);
+    Prefixes.push_back(D.SysRoot + "/usr");
+    Prefixes.push_back(D.InstalledDir + "/..");
+  }
+
+  // Loop over the various components which exist and select the best GCC
+  // installation available. GCC installs are ranked by version number.
+  Version = GCCVersion::Parse("0.0.0");
+  for (unsigned i = 0, ie = Prefixes.size(); i < ie; ++i) {
+    if (!llvm::sys::fs::exists(Prefixes[i]))
+      continue;
+    for (unsigned j = 0, je = CandidateLibDirs.size(); j < je; ++j) {
+      const std::string LibDir = Prefixes[i] + CandidateLibDirs[j].str();
+      if (!llvm::sys::fs::exists(LibDir))
+        continue;
+      for (unsigned k = 0, ke = CandidateTripleAliases.size(); k < ke; ++k)
+        ScanLibDirForGCCTriple(TargetArch, LibDir, CandidateTripleAliases[k]);
+    }
+    for (unsigned j = 0, je = CandidateMultiarchLibDirs.size(); j < je; ++j) {
+      const std::string LibDir
+        = Prefixes[i] + CandidateMultiarchLibDirs[j].str();
+      if (!llvm::sys::fs::exists(LibDir))
+        continue;
+      for (unsigned k = 0, ke = CandidateMultiarchTripleAliases.size(); k < ke;
+           ++k)
+        ScanLibDirForGCCTriple(TargetArch, LibDir,
+                               CandidateMultiarchTripleAliases[k],
+                               /*NeedsMultiarchSuffix=*/true);
+    }
+  }
+}
+
+/*static*/ void Generic_GCC::GCCInstallationDetector::CollectLibDirsAndTriples(
+    const llvm::Triple &TargetTriple,
+    const llvm::Triple &MultiarchTriple,
+    SmallVectorImpl<StringRef> &LibDirs,
+    SmallVectorImpl<StringRef> &TripleAliases,
+    SmallVectorImpl<StringRef> &MultiarchLibDirs,
+    SmallVectorImpl<StringRef> &MultiarchTripleAliases) {
+  // Declare a bunch of static data sets that we'll select between below. These
+  // are specifically designed to always refer to string literals to avoid any
+  // lifetime or initialization issues.
+  static const char *const ARMLibDirs[] = { "/lib" };
+  static const char *const ARMTriples[] = {
+    "arm-linux-gnueabi",
+    "arm-linux-androideabi"
+  };
+
+  static const char *const X86_64LibDirs[] = { "/lib64", "/lib" };
+  static const char *const X86_64Triples[] = {
+    "x86_64-linux-gnu",
+    "x86_64-unknown-linux-gnu",
+    "x86_64-pc-linux-gnu",
+    "x86_64-redhat-linux6E",
+    "x86_64-redhat-linux",
+    "x86_64-suse-linux",
+    "x86_64-manbo-linux-gnu",
+    "x86_64-linux-gnu",
+    "x86_64-slackware-linux"
+  };
+  static const char *const X86LibDirs[] = { "/lib32", "/lib" };
+  static const char *const X86Triples[] = {
+    "i686-linux-gnu",
+    "i686-pc-linux-gnu",
+    "i486-linux-gnu",
+    "i386-linux-gnu",
+    "i686-redhat-linux",
+    "i586-redhat-linux",
+    "i386-redhat-linux",
+    "i586-suse-linux",
+    "i486-slackware-linux"
+  };
+
+  static const char *const MIPSLibDirs[] = { "/lib" };
+  static const char *const MIPSTriples[] = { "mips-linux-gnu" };
+  static const char *const MIPSELLibDirs[] = { "/lib" };
+  static const char *const MIPSELTriples[] = { "mipsel-linux-gnu" };
+
+  static const char *const PPCLibDirs[] = { "/lib32", "/lib" };
+  static const char *const PPCTriples[] = {
+    "powerpc-linux-gnu",
+    "powerpc-unknown-linux-gnu",
+    "powerpc-suse-linux"
+  };
+  static const char *const PPC64LibDirs[] = { "/lib64", "/lib" };
+  static const char *const PPC64Triples[] = {
+    "powerpc64-linux-gnu",
+    "powerpc64-unknown-linux-gnu",
+    "powerpc64-suse-linux",
+    "ppc64-redhat-linux"
+  };
+
+  switch (TargetTriple.getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    LibDirs.append(ARMLibDirs, ARMLibDirs + llvm::array_lengthof(ARMLibDirs));
+    TripleAliases.append(
+      ARMTriples, ARMTriples + llvm::array_lengthof(ARMTriples));
+    break;
+  case llvm::Triple::x86_64:
+    LibDirs.append(
+      X86_64LibDirs, X86_64LibDirs + llvm::array_lengthof(X86_64LibDirs));
+    TripleAliases.append(
+      X86_64Triples, X86_64Triples + llvm::array_lengthof(X86_64Triples));
+    MultiarchLibDirs.append(
+      X86LibDirs, X86LibDirs + llvm::array_lengthof(X86LibDirs));
+    MultiarchTripleAliases.append(
+      X86Triples, X86Triples + llvm::array_lengthof(X86Triples));
+    break;
+  case llvm::Triple::x86:
+    LibDirs.append(X86LibDirs, X86LibDirs + llvm::array_lengthof(X86LibDirs));
+    TripleAliases.append(
+      X86Triples, X86Triples + llvm::array_lengthof(X86Triples));
+    MultiarchLibDirs.append(
+      X86_64LibDirs, X86_64LibDirs + llvm::array_lengthof(X86_64LibDirs));
+    MultiarchTripleAliases.append(
+      X86_64Triples, X86_64Triples + llvm::array_lengthof(X86_64Triples));
+    break;
+  case llvm::Triple::mips:
+    LibDirs.append(
+      MIPSLibDirs, MIPSLibDirs + llvm::array_lengthof(MIPSLibDirs));
+    TripleAliases.append(
+      MIPSTriples, MIPSTriples + llvm::array_lengthof(MIPSTriples));
+    break;
+  case llvm::Triple::mipsel:
+    LibDirs.append(
+      MIPSELLibDirs, MIPSELLibDirs + llvm::array_lengthof(MIPSELLibDirs));
+    TripleAliases.append(
+      MIPSELTriples, MIPSELTriples + llvm::array_lengthof(MIPSELTriples));
+    break;
+  case llvm::Triple::ppc:
+    LibDirs.append(PPCLibDirs, PPCLibDirs + llvm::array_lengthof(PPCLibDirs));
+    TripleAliases.append(
+      PPCTriples, PPCTriples + llvm::array_lengthof(PPCTriples));
+    MultiarchLibDirs.append(
+      PPC64LibDirs, PPC64LibDirs + llvm::array_lengthof(PPC64LibDirs));
+    MultiarchTripleAliases.append(
+      PPC64Triples, PPC64Triples + llvm::array_lengthof(PPC64Triples));
+    break;
+  case llvm::Triple::ppc64:
+    LibDirs.append(
+      PPC64LibDirs, PPC64LibDirs + llvm::array_lengthof(PPC64LibDirs));
+    TripleAliases.append(
+      PPC64Triples, PPC64Triples + llvm::array_lengthof(PPC64Triples));
+    MultiarchLibDirs.append(
+      PPCLibDirs, PPCLibDirs + llvm::array_lengthof(PPCLibDirs));
+    MultiarchTripleAliases.append(
+      PPCTriples, PPCTriples + llvm::array_lengthof(PPCTriples));
+    break;
+
+  default:
+    // By default, just rely on the standard lib directories and the original
+    // triple.
+    break;
+  }
+
+  // Always append the drivers target triple to the end, in case it doesn't
+  // match any of our aliases.
+  TripleAliases.push_back(TargetTriple.str());
+
+  // Also include the multiarch variant if it's different.
+  if (TargetTriple.str() != MultiarchTriple.str())
+    MultiarchTripleAliases.push_back(MultiarchTriple.str());
+}
+
+void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
+    llvm::Triple::ArchType TargetArch, const std::string &LibDir,
+    StringRef CandidateTriple, bool NeedsMultiarchSuffix) {
+  // There are various different suffixes involving the triple we
+  // check for. We also record what is necessary to walk from each back
+  // up to the lib directory.
+  const std::string LibSuffixes[] = {
+    "/gcc/" + CandidateTriple.str(),
+    "/" + CandidateTriple.str() + "/gcc/" + CandidateTriple.str(),
+
+    // Ubuntu has a strange mis-matched pair of triples that this happens to
+    // match.
+    // FIXME: It may be worthwhile to generalize this and look for a second
+    // triple.
+    "/i386-linux-gnu/gcc/" + CandidateTriple.str()
+  };
+  const std::string InstallSuffixes[] = {
+    "/../../..",
+    "/../../../..",
+    "/../../../.."
+  };
+  // Only look at the final, weird Ubuntu suffix for i386-linux-gnu.
+  const unsigned NumLibSuffixes = (llvm::array_lengthof(LibSuffixes) -
+                                   (TargetArch != llvm::Triple::x86));
+  for (unsigned i = 0; i < NumLibSuffixes; ++i) {
+    StringRef LibSuffix = LibSuffixes[i];
+    llvm::error_code EC;
+    for (llvm::sys::fs::directory_iterator LI(LibDir + LibSuffix, EC), LE;
+         !EC && LI != LE; LI = LI.increment(EC)) {
+      StringRef VersionText = llvm::sys::path::filename(LI->path());
+      GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
+      static const GCCVersion MinVersion = { "4.1.1", 4, 1, 1, "" };
+      if (CandidateVersion < MinVersion)
+        continue;
+      if (CandidateVersion <= Version)
+        continue;
+
+      // Some versions of SUSE and Fedora on ppc64 put 32-bit libs
+      // in what would normally be GCCInstallPath and put the 64-bit
+      // libs in a subdirectory named 64. The simple logic we follow is that
+      // *if* there is a subdirectory of the right name with crtbegin.o in it,
+      // we use that. If not, and if not a multiarch triple, we look for
+      // crtbegin.o without the subdirectory.
+      StringRef MultiarchSuffix
+        = (TargetArch == llvm::Triple::x86_64 ||
+           TargetArch == llvm::Triple::ppc64) ? "/64" : "/32";
+      if (llvm::sys::fs::exists(LI->path() + MultiarchSuffix + "/crtbegin.o")) {
+        GCCMultiarchSuffix = MultiarchSuffix.str();
+      } else {
+        if (NeedsMultiarchSuffix ||
+            !llvm::sys::fs::exists(LI->path() + "/crtbegin.o"))
+          continue;
+        GCCMultiarchSuffix.clear();
+      }
+
+      Version = CandidateVersion;
+      GCCTriple.setTriple(CandidateTriple);
+      // FIXME: We hack together the directory name here instead of
+      // using LI to ensure stable path separators across Windows and
+      // Linux.
+      GCCInstallPath = LibDir + LibSuffixes[i] + "/" + VersionText.str();
+      GCCParentLibPath = GCCInstallPath + InstallSuffixes[i];
+      IsValid = true;
+    }
+  }
+}
+
+Generic_GCC::Generic_GCC(const Driver &D, const llvm::Triple& Triple,
+                         const ArgList &Args)
+  : ToolChain(D, Triple), GCCInstallation(getDriver(), Triple, Args) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+}
+
+Generic_GCC::~Generic_GCC() {
+  // Free tool implementations.
+  for (llvm::DenseMap<unsigned, Tool*>::iterator
+         it = Tools.begin(), ie = Tools.end(); it != ie; ++it)
+    delete it->second;
+}
+
+Tool &Generic_GCC::SelectTool(const Compilation &C,
+                              const JobAction &JA,
+                              const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::InputClass:
+    case Action::BindArchClass:
+      llvm_unreachable("Invalid tool kind.");
+    case Action::PreprocessJobClass:
+      T = new tools::gcc::Preprocess(*this); break;
+    case Action::PrecompileJobClass:
+      T = new tools::gcc::Precompile(*this); break;
+    case Action::AnalyzeJobClass:
+    case Action::MigrateJobClass:
+      T = new tools::Clang(*this); break;
+    case Action::CompileJobClass:
+      T = new tools::gcc::Compile(*this); break;
+    case Action::AssembleJobClass:
+      T = new tools::gcc::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::gcc::Link(*this); break;
+
+      // This is a bit ungeneric, but the only platform using a driver
+      // driver is Darwin.
+    case Action::LipoJobClass:
+      T = new tools::darwin::Lipo(*this); break;
+    case Action::DsymutilJobClass:
+      T = new tools::darwin::Dsymutil(*this); break;
+    case Action::VerifyJobClass:
+      T = new tools::darwin::VerifyDebug(*this); break;
+    }
+  }
+
+  return *T;
+}
+
+bool Generic_GCC::IsUnwindTablesDefault() const {
+  // FIXME: Gross; we should probably have some separate target
+  // definition, possibly even reusing the one in clang.
+  return getArchName() == "x86_64";
+}
+
+const char *Generic_GCC::GetDefaultRelocationModel() const {
+  return "static";
+}
+
+const char *Generic_GCC::GetForcedPicModel() const {
+  return 0;
+}
+/// Hexagon Toolchain
+
+Hexagon_TC::Hexagon_TC(const Driver &D, const llvm::Triple& Triple)
+  : ToolChain(D, Triple) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir.c_str())
+    getProgramPaths().push_back(getDriver().Dir);
+}
+
+Hexagon_TC::~Hexagon_TC() {
+  // Free tool implementations.
+  for (llvm::DenseMap<unsigned, Tool*>::iterator
+         it = Tools.begin(), ie = Tools.end(); it != ie; ++it)
+    delete it->second;
+}
+
+Tool &Hexagon_TC::SelectTool(const Compilation &C,
+                             const JobAction &JA,
+                             const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  //   if (JA.getKind () == Action::CompileJobClass)
+  //     Key = JA.getKind ();
+  //     else
+
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+  //   if ((JA.getKind () == Action::CompileJobClass)
+  //     && (JA.getType () != types::TY_LTO_BC)) {
+  //     Key = JA.getKind ();
+  //   }
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::InputClass:
+    case Action::BindArchClass:
+      assert(0 && "Invalid tool kind.");
+    case Action::AnalyzeJobClass:
+      T = new tools::Clang(*this); break;
+    case Action::AssembleJobClass:
+      T = new tools::hexagon::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::hexagon::Link(*this); break;
+    default:
+      assert(false && "Unsupported action for Hexagon target.");
+    }
+  }
+
+  return *T;
+}
+
+bool Hexagon_TC::IsUnwindTablesDefault() const {
+  // FIXME: Gross; we should probably have some separate target
+  // definition, possibly even reusing the one in clang.
+  return getArchName() == "x86_64";
+}
+
+const char *Hexagon_TC::GetDefaultRelocationModel() const {
+  return "static";
+}
+
+const char *Hexagon_TC::GetForcedPicModel() const {
+  return 0;
+} // End Hexagon
+
+
+/// TCEToolChain - A tool chain using the llvm bitcode tools to perform
+/// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
+/// Currently does not support anything else but compilation.
+
+TCEToolChain::TCEToolChain(const Driver &D, const llvm::Triple& Triple)
+  : ToolChain(D, Triple) {
+  // Path mangling to find libexec
+  std::string Path(getDriver().Dir);
+
+  Path += "/../libexec";
+  getProgramPaths().push_back(Path);
+}
+
+TCEToolChain::~TCEToolChain() {
+  for (llvm::DenseMap<unsigned, Tool*>::iterator
+           it = Tools.begin(), ie = Tools.end(); it != ie; ++it)
+      delete it->second;
+}
+
+bool TCEToolChain::IsMathErrnoDefault() const {
+  return true;
+}
+
+bool TCEToolChain::IsUnwindTablesDefault() const {
+  return false;
+}
+
+const char *TCEToolChain::GetDefaultRelocationModel() const {
+  return "static";
+}
+
+const char *TCEToolChain::GetForcedPicModel() const {
+  return 0;
+}
+
+Tool &TCEToolChain::SelectTool(const Compilation &C,
+                            const JobAction &JA,
+                               const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  Key = Action::AnalyzeJobClass;
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::PreprocessJobClass:
+      T = new tools::gcc::Preprocess(*this); break;
+    case Action::AnalyzeJobClass:
+      T = new tools::Clang(*this); break;
+    default:
+     llvm_unreachable("Unsupported action for TCE target.");
+    }
+  }
+  return *T;
+}
+
+/// OpenBSD - OpenBSD tool chain which can call as(1) and ld(1) directly.
+
+OpenBSD::OpenBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+}
+
+Tool &OpenBSD::SelectTool(const Compilation &C, const JobAction &JA,
+                          const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass: {
+      if (UseIntegratedAs)
+        T = new tools::ClangAs(*this);
+      else
+        T = new tools::openbsd::Assemble(*this);
+      break;
+    }
+    case Action::LinkJobClass:
+      T = new tools::openbsd::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// FreeBSD - FreeBSD tool chain which can call as(1) and ld(1) directly.
+
+FreeBSD::FreeBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+
+  // When targeting 32-bit platforms, look for '/usr/lib32/crt1.o' and fall
+  // back to '/usr/lib' if it doesn't exist.
+  if ((Triple.getArch() == llvm::Triple::x86 ||
+       Triple.getArch() == llvm::Triple::ppc) &&
+      llvm::sys::fs::exists(getDriver().SysRoot + "/usr/lib32/crt1.o"))
+    getFilePaths().push_back(getDriver().SysRoot + "/usr/lib32");
+  else
+    getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
+}
+
+Tool &FreeBSD::SelectTool(const Compilation &C, const JobAction &JA,
+                          const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      if (UseIntegratedAs)
+        T = new tools::ClangAs(*this);
+      else
+        T = new tools::freebsd::Assemble(*this);
+      break;
+    case Action::LinkJobClass:
+      T = new tools::freebsd::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
+
+NetBSD::NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+
+  if (getDriver().UseStdLib) {
+    // When targeting a 32-bit platform, try the special directory used on
+    // 64-bit hosts, and only fall back to the main library directory if that
+    // doesn't work.
+    // FIXME: It'd be nicer to test if this directory exists, but I'm not sure
+    // what all logic is needed to emulate the '=' prefix here.
+    if (Triple.getArch() == llvm::Triple::x86)
+      getFilePaths().push_back("=/usr/lib/i386");
+
+    getFilePaths().push_back("=/usr/lib");
+  }
+}
+
+Tool &NetBSD::SelectTool(const Compilation &C, const JobAction &JA,
+                         const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      if (UseIntegratedAs)
+        T = new tools::ClangAs(*this);
+      else
+        T = new tools::netbsd::Assemble(*this);
+      break;
+    case Action::LinkJobClass:
+      T = new tools::netbsd::Link(*this);
+      break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// Minix - Minix tool chain which can call as(1) and ld(1) directly.
+
+Minix::Minix(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+}
+
+Tool &Minix::SelectTool(const Compilation &C, const JobAction &JA,
+                        const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      T = new tools::minix::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::minix::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// AuroraUX - AuroraUX tool chain which can call as(1) and ld(1) directly.
+
+AuroraUX::AuroraUX(const Driver &D, const llvm::Triple& Triple,
+                   const ArgList &Args)
+  : Generic_GCC(D, Triple, Args) {
+
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+  getFilePaths().push_back("/usr/sfw/lib");
+  getFilePaths().push_back("/opt/gcc4/lib");
+  getFilePaths().push_back("/opt/gcc4/lib/gcc/i386-pc-solaris2.11/4.2.4");
+
+}
+
+Tool &AuroraUX::SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      T = new tools::auroraux::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::auroraux::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// Solaris - Solaris tool chain which can call as(1) and ld(1) directly.
+
+Solaris::Solaris(const Driver &D, const llvm::Triple& Triple,
+                 const ArgList &Args)
+  : Generic_GCC(D, Triple, Args) {
+
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+}
+
+Tool &Solaris::SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      T = new tools::solaris::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::solaris::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+/// Linux toolchain (very bare-bones at the moment).
+
+enum LinuxDistro {
+  ArchLinux,
+  DebianLenny,
+  DebianSqueeze,
+  DebianWheezy,
+  Exherbo,
+  RHEL4,
+  RHEL5,
+  RHEL6,
+  Fedora13,
+  Fedora14,
+  Fedora15,
+  Fedora16,
+  FedoraRawhide,
+  OpenSuse11_3,
+  OpenSuse11_4,
+  OpenSuse12_1,
+  OpenSuse12_2,
+  UbuntuHardy,
+  UbuntuIntrepid,
+  UbuntuJaunty,
+  UbuntuKarmic,
+  UbuntuLucid,
+  UbuntuMaverick,
+  UbuntuNatty,
+  UbuntuOneiric,
+  UbuntuPrecise,
+  UnknownDistro
+};
+
+static bool IsRedhat(enum LinuxDistro Distro) {
+  return (Distro >= Fedora13 && Distro <= FedoraRawhide) ||
+         (Distro >= RHEL4    && Distro <= RHEL6);
+}
+
+static bool IsOpenSuse(enum LinuxDistro Distro) {
+  return Distro >= OpenSuse11_3 && Distro <= OpenSuse12_2;
+}
+
+static bool IsDebian(enum LinuxDistro Distro) {
+  return Distro >= DebianLenny && Distro <= DebianWheezy;
+}
+
+static bool IsUbuntu(enum LinuxDistro Distro) {
+  return Distro >= UbuntuHardy && Distro <= UbuntuPrecise;
+}
+
+static LinuxDistro DetectLinuxDistro(llvm::Triple::ArchType Arch) {
+  OwningPtr<llvm::MemoryBuffer> File;
+  if (!llvm::MemoryBuffer::getFile("/etc/lsb-release", File)) {
+    StringRef Data = File.get()->getBuffer();
+    SmallVector<StringRef, 8> Lines;
+    Data.split(Lines, "\n");
+    LinuxDistro Version = UnknownDistro;
+    for (unsigned i = 0, s = Lines.size(); i != s; ++i)
+      if (Version == UnknownDistro && Lines[i].startswith("DISTRIB_CODENAME="))
+        Version = llvm::StringSwitch<LinuxDistro>(Lines[i].substr(17))
+          .Case("hardy", UbuntuHardy)
+          .Case("intrepid", UbuntuIntrepid)
+          .Case("jaunty", UbuntuJaunty)
+          .Case("karmic", UbuntuKarmic)
+          .Case("lucid", UbuntuLucid)
+          .Case("maverick", UbuntuMaverick)
+          .Case("natty", UbuntuNatty)
+          .Case("oneiric", UbuntuOneiric)
+          .Case("precise", UbuntuPrecise)
+          .Default(UnknownDistro);
+    return Version;
+  }
+
+  if (!llvm::MemoryBuffer::getFile("/etc/redhat-release", File)) {
+    StringRef Data = File.get()->getBuffer();
+    if (Data.startswith("Fedora release 16"))
+      return Fedora16;
+    else if (Data.startswith("Fedora release 15"))
+      return Fedora15;
+    else if (Data.startswith("Fedora release 14"))
+      return Fedora14;
+    else if (Data.startswith("Fedora release 13"))
+      return Fedora13;
+    else if (Data.startswith("Fedora release") &&
+             Data.find("Rawhide") != StringRef::npos)
+      return FedoraRawhide;
+    else if (Data.startswith("Red Hat Enterprise Linux") &&
+             Data.find("release 6") != StringRef::npos)
+      return RHEL6;
+    else if ((Data.startswith("Red Hat Enterprise Linux") ||
+	      Data.startswith("CentOS")) &&
+             Data.find("release 5") != StringRef::npos)
+      return RHEL5;
+    else if ((Data.startswith("Red Hat Enterprise Linux") ||
+	      Data.startswith("CentOS")) &&
+             Data.find("release 4") != StringRef::npos)
+      return RHEL4;
+    return UnknownDistro;
+  }
+
+  if (!llvm::MemoryBuffer::getFile("/etc/debian_version", File)) {
+    StringRef Data = File.get()->getBuffer();
+    if (Data[0] == '5')
+      return DebianLenny;
+    else if (Data.startswith("squeeze/sid") || Data[0] == '6')
+      return DebianSqueeze;
+    else if (Data.startswith("wheezy/sid")  || Data[0] == '7')
+      return DebianWheezy;
+    return UnknownDistro;
+  }
+
+  if (!llvm::MemoryBuffer::getFile("/etc/SuSE-release", File))
+    return llvm::StringSwitch<LinuxDistro>(File.get()->getBuffer())
+      .StartsWith("openSUSE 11.3", OpenSuse11_3)
+      .StartsWith("openSUSE 11.4", OpenSuse11_4)
+      .StartsWith("openSUSE 12.1", OpenSuse12_1)
+      .StartsWith("openSUSE 12.2", OpenSuse12_2)
+      .Default(UnknownDistro);
+
+  bool Exists;
+  if (!llvm::sys::fs::exists("/etc/exherbo-release", Exists) && Exists)
+    return Exherbo;
+
+  if (!llvm::sys::fs::exists("/etc/arch-release", Exists) && Exists)
+    return ArchLinux;
+
+  return UnknownDistro;
+}
+
+/// \brief Get our best guess at the multiarch triple for a target.
+///
+/// Debian-based systems are starting to use a multiarch setup where they use
+/// a target-triple directory in the library and header search paths.
+/// Unfortunately, this triple does not align with the vanilla target triple,
+/// so we provide a rough mapping here.
+static std::string getMultiarchTriple(const llvm::Triple TargetTriple,
+                                      StringRef SysRoot) {
+  // For most architectures, just use whatever we have rather than trying to be
+  // clever.
+  switch (TargetTriple.getArch()) {
+  default:
+    return TargetTriple.str();
+
+    // We use the existence of '/lib/<triple>' as a directory to detect some
+    // common linux triples that don't quite match the Clang triple for both
+    // 32-bit and 64-bit targets. Multiarch fixes its install triples to these
+    // regardless of what the actual target triple is.
+  case llvm::Triple::x86:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/i386-linux-gnu"))
+      return "i386-linux-gnu";
+    return TargetTriple.str();
+  case llvm::Triple::x86_64:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/x86_64-linux-gnu"))
+      return "x86_64-linux-gnu";
+    return TargetTriple.str();
+  case llvm::Triple::mips:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/mips-linux-gnu"))
+      return "mips-linux-gnu";
+    return TargetTriple.str();
+  case llvm::Triple::mipsel:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/mipsel-linux-gnu"))
+      return "mipsel-linux-gnu";
+    return TargetTriple.str();
+  case llvm::Triple::ppc:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/powerpc-linux-gnu"))
+      return "powerpc-linux-gnu";
+    return TargetTriple.str();
+  case llvm::Triple::ppc64:
+    if (llvm::sys::fs::exists(SysRoot + "/lib/powerpc64-linux-gnu"))
+      return "powerpc64-linux-gnu";
+    return TargetTriple.str();
+  }
+}
+
+static void addPathIfExists(Twine Path, ToolChain::path_list &Paths) {
+  if (llvm::sys::fs::exists(Path)) Paths.push_back(Path.str());
+}
+
+Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+  llvm::Triple::ArchType Arch = Triple.getArch();
+  const std::string &SysRoot = getDriver().SysRoot;
+
+  // OpenSuse stores the linker with the compiler, add that to the search
+  // path.
+  ToolChain::path_list &PPaths = getProgramPaths();
+  PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
+                         GCCInstallation.getTriple().str() + "/bin").str());
+
+  Linker = GetProgramPath("ld");
+
+  LinuxDistro Distro = DetectLinuxDistro(Arch);
+
+  if (IsOpenSuse(Distro) || IsUbuntu(Distro)) {
+    ExtraOpts.push_back("-z");
+    ExtraOpts.push_back("relro");
+  }
+
+  if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)
+    ExtraOpts.push_back("-X");
+
+  const bool IsMips = Arch == llvm::Triple::mips ||
+                      Arch == llvm::Triple::mipsel ||
+                      Arch == llvm::Triple::mips64 ||
+                      Arch == llvm::Triple::mips64el;
+
+  const bool IsAndroid = Triple.getEnvironment() == llvm::Triple::ANDROIDEABI;
+
+  // Do not use 'gnu' hash style for Mips targets because .gnu.hash
+  // and the MIPS ABI require .dynsym to be sorted in different ways.
+  // .gnu.hash needs symbols to be grouped by hash code whereas the MIPS
+  // ABI requires a mapping between the GOT and the symbol table.
+  // Android loader does not support .gnu.hash.
+  if (!IsMips && !IsAndroid) {
+    if (IsRedhat(Distro) || IsOpenSuse(Distro) ||
+        (IsUbuntu(Distro) && Distro >= UbuntuMaverick))
+      ExtraOpts.push_back("--hash-style=gnu");
+
+    if (IsDebian(Distro) || IsOpenSuse(Distro) || Distro == UbuntuLucid ||
+        Distro == UbuntuJaunty || Distro == UbuntuKarmic)
+      ExtraOpts.push_back("--hash-style=both");
+  }
+
+  if (IsRedhat(Distro))
+    ExtraOpts.push_back("--no-add-needed");
+
+  if (Distro == DebianSqueeze || Distro == DebianWheezy ||
+      IsOpenSuse(Distro) ||
+      (IsRedhat(Distro) && Distro != RHEL4 && Distro != RHEL5) ||
+      (IsUbuntu(Distro) && Distro >= UbuntuKarmic))
+    ExtraOpts.push_back("--build-id");
+
+  if (IsOpenSuse(Distro))
+    ExtraOpts.push_back("--enable-new-dtags");
+
+  // The selection of paths to try here is designed to match the patterns which
+  // the GCC driver itself uses, as this is part of the GCC-compatible driver.
+  // This was determined by running GCC in a fake filesystem, creating all
+  // possible permutations of these directories, and seeing which ones it added
+  // to the link paths.
+  path_list &Paths = getFilePaths();
+
+  const std::string Multilib = Triple.isArch32Bit() ? "lib32" : "lib64";
+  const std::string MultiarchTriple = getMultiarchTriple(Triple, SysRoot);
+
+  // Add the multilib suffixed paths where they are available.
+  if (GCCInstallation.isValid()) {
+    const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
+    const std::string &LibPath = GCCInstallation.getParentLibPath();
+    addPathIfExists((GCCInstallation.getInstallPath() +
+                     GCCInstallation.getMultiarchSuffix()),
+                    Paths);
+
+    // If the GCC installation we found is inside of the sysroot, we want to
+    // prefer libraries installed in the parent prefix of the GCC installation.
+    // It is important to *not* use these paths when the GCC installation is
+    // outside of the system root as that can pick up unintended libraries.
+    // This usually happens when there is an external cross compiler on the
+    // host system, and a more minimal sysroot available that is the target of
+    // the cross.
+    if (StringRef(LibPath).startswith(SysRoot)) {
+      addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib/../" + Multilib,
+                      Paths);
+      addPathIfExists(LibPath + "/" + MultiarchTriple, Paths);
+      addPathIfExists(LibPath + "/../" + Multilib, Paths);
+    }
+  }
+  addPathIfExists(SysRoot + "/lib/" + MultiarchTriple, Paths);
+  addPathIfExists(SysRoot + "/lib/../" + Multilib, Paths);
+  addPathIfExists(SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
+  addPathIfExists(SysRoot + "/usr/lib/../" + Multilib, Paths);
+
+  // Try walking via the GCC triple path in case of multiarch GCC
+  // installations with strange symlinks.
+  if (GCCInstallation.isValid())
+    addPathIfExists(SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str() +
+                    "/../../" + Multilib, Paths);
+
+  // Add the non-multilib suffixed paths (if potentially different).
+  if (GCCInstallation.isValid()) {
+    const std::string &LibPath = GCCInstallation.getParentLibPath();
+    const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
+    if (!GCCInstallation.getMultiarchSuffix().empty())
+      addPathIfExists(GCCInstallation.getInstallPath(), Paths);
+
+    if (StringRef(LibPath).startswith(SysRoot)) {
+      addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib", Paths);
+      addPathIfExists(LibPath, Paths);
+    }
+  }
+  addPathIfExists(SysRoot + "/lib", Paths);
+  addPathIfExists(SysRoot + "/usr/lib", Paths);
+}
+
+bool Linux::HasNativeLLVMSupport() const {
+  return true;
+}
+
+Tool &Linux::SelectTool(const Compilation &C, const JobAction &JA,
+                        const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      if (UseIntegratedAs)
+        T = new tools::ClangAs(*this);
+      else
+        T = new tools::linuxtools::Assemble(*this);
+      break;
+    case Action::LinkJobClass:
+      T = new tools::linuxtools::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
+
+void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                      ArgStringList &CC1Args) const {
+  const Driver &D = getDriver();
+
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
+    return;
+
+  if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
+    addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/usr/local/include");
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    llvm::sys::Path P(D.ResourceDir);
+    P.appendComponent("include");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  // Check for configure-time C include directories.
+  StringRef CIncludeDirs(C_INCLUDE_DIRS);
+  if (CIncludeDirs != "") {
+    SmallVector<StringRef, 5> dirs;
+    CIncludeDirs.split(dirs, ":");
+    for (SmallVectorImpl<StringRef>::iterator I = dirs.begin(), E = dirs.end();
+         I != E; ++I) {
+      StringRef Prefix = llvm::sys::path::is_absolute(*I) ? D.SysRoot : "";
+      addExternCSystemInclude(DriverArgs, CC1Args, Prefix + *I);
+    }
+    return;
+  }
+
+  // Lacking those, try to detect the correct set of system includes for the
+  // target triple.
+
+  // Implement generic Debian multiarch support.
+  const StringRef X86_64MultiarchIncludeDirs[] = {
+    "/usr/include/x86_64-linux-gnu",
+
+    // FIXME: These are older forms of multiarch. It's not clear that they're
+    // in use in any released version of Debian, so we should consider
+    // removing them.
+    "/usr/include/i686-linux-gnu/64",
+    "/usr/include/i486-linux-gnu/64"
+  };
+  const StringRef X86MultiarchIncludeDirs[] = {
+    "/usr/include/i386-linux-gnu",
+
+    // FIXME: These are older forms of multiarch. It's not clear that they're
+    // in use in any released version of Debian, so we should consider
+    // removing them.
+    "/usr/include/x86_64-linux-gnu/32",
+    "/usr/include/i686-linux-gnu",
+    "/usr/include/i486-linux-gnu"
+  };
+  const StringRef ARMMultiarchIncludeDirs[] = {
+    "/usr/include/arm-linux-gnueabi"
+  };
+  const StringRef MIPSMultiarchIncludeDirs[] = {
+    "/usr/include/mips-linux-gnu"
+  };
+  const StringRef MIPSELMultiarchIncludeDirs[] = {
+    "/usr/include/mipsel-linux-gnu"
+  };
+  const StringRef PPCMultiarchIncludeDirs[] = {
+    "/usr/include/powerpc-linux-gnu"
+  };
+  const StringRef PPC64MultiarchIncludeDirs[] = {
+    "/usr/include/powerpc64-linux-gnu"
+  };
+  ArrayRef<StringRef> MultiarchIncludeDirs;
+  if (getTriple().getArch() == llvm::Triple::x86_64) {
+    MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::x86) {
+    MultiarchIncludeDirs = X86MultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::arm) {
+    MultiarchIncludeDirs = ARMMultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::mips) {
+    MultiarchIncludeDirs = MIPSMultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::mipsel) {
+    MultiarchIncludeDirs = MIPSELMultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::ppc) {
+    MultiarchIncludeDirs = PPCMultiarchIncludeDirs;
+  } else if (getTriple().getArch() == llvm::Triple::ppc64) {
+    MultiarchIncludeDirs = PPC64MultiarchIncludeDirs;
+  }
+  for (ArrayRef<StringRef>::iterator I = MultiarchIncludeDirs.begin(),
+                                     E = MultiarchIncludeDirs.end();
+       I != E; ++I) {
+    if (llvm::sys::fs::exists(D.SysRoot + *I)) {
+      addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + *I);
+      break;
+    }
+  }
+
+  if (getTriple().getOS() == llvm::Triple::RTEMS)
+    return;
+
+  // Add an include of '/include' directly. This isn't provided by default by
+  // system GCCs, but is often used with cross-compiling GCCs, and harmless to
+  // add even when Clang is acting as-if it were a system compiler.
+  addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
+
+  addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/usr/include");
+}
+
+/// \brief Helper to add the thre variant paths for a libstdc++ installation.
+/*static*/ bool Linux::addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,
+                                                const ArgList &DriverArgs,
+                                                ArgStringList &CC1Args) {
+  if (!llvm::sys::fs::exists(Base))
+    return false;
+  addSystemInclude(DriverArgs, CC1Args, Base);
+  addSystemInclude(DriverArgs, CC1Args, Base + "/" + TargetArchDir);
+  addSystemInclude(DriverArgs, CC1Args, Base + "/backward");
+  return true;
+}
+
+void Linux::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                         ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  // Check if libc++ has been enabled and provide its include paths if so.
+  if (GetCXXStdlibType(DriverArgs) == ToolChain::CST_Libcxx) {
+    // libc++ is always installed at a fixed path on Linux currently.
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/v1");
+    return;
+  }
+
+  // We need a detected GCC installation on Linux to provide libstdc++'s
+  // headers. We handled the libc++ case above.
+  if (!GCCInstallation.isValid())
+    return;
+
+  // By default, look for the C++ headers in an include directory adjacent to
+  // the lib directory of the GCC installation. Note that this is expect to be
+  // equivalent to '/usr/include/c++/X.Y' in almost all cases.
+  StringRef LibDir = GCCInstallation.getParentLibPath();
+  StringRef InstallDir = GCCInstallation.getInstallPath();
+  StringRef Version = GCCInstallation.getVersion();
+  if (!addLibStdCXXIncludePaths(LibDir + "/../include/c++/" + Version,
+                                (GCCInstallation.getTriple().str() +
+                                 GCCInstallation.getMultiarchSuffix()),
+                                DriverArgs, CC1Args)) {
+    // Gentoo is weird and places its headers inside the GCC install, so if the
+    // first attempt to find the headers fails, try this pattern.
+    addLibStdCXXIncludePaths(InstallDir + "/include/g++-v4",
+                             (GCCInstallation.getTriple().str() +
+                              GCCInstallation.getMultiarchSuffix()),
+                             DriverArgs, CC1Args);
+  }
+}
+
+/// DragonFly - DragonFly tool chain which can call as(1) and ld(1) directly.
+
+DragonFly::DragonFly(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+
+  // Path mangling to find libexec
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+  getFilePaths().push_back("/usr/lib/gcc41");
+}
+
+Tool &DragonFly::SelectTool(const Compilation &C, const JobAction &JA,
+                            const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::AssembleJobClass:
+      T = new tools::dragonfly::Assemble(*this); break;
+    case Action::LinkJobClass:
+      T = new tools::dragonfly::Link(*this); break;
+    default:
+      T = &Generic_GCC::SelectTool(C, JA, Inputs);
+    }
+  }
+
+  return *T;
+}
diff --git a/clang/lib/Driver/ToolChains.h b/clang/lib/Driver/ToolChains.h
new file mode 100644
index 0000000..eaa6be1
--- /dev/null
+++ b/clang/lib/Driver/ToolChains.h
@@ -0,0 +1,596 @@
+//===--- ToolChains.h - ToolChain Implementations ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLANG_LIB_DRIVER_TOOLCHAINS_H_
+#define CLANG_LIB_DRIVER_TOOLCHAINS_H_
+
+#include "clang/Driver/Action.h"
+#include "clang/Driver/ToolChain.h"
+
+#include "clang/Basic/VersionTuple.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/Compiler.h"
+
+#include "Tools.h"
+
+namespace clang {
+namespace driver {
+namespace toolchains {
+
+/// Generic_GCC - A tool chain using the 'gcc' command to perform
+/// all subcommands; this relies on gcc translating the majority of
+/// command line options.
+class LLVM_LIBRARY_VISIBILITY Generic_GCC : public ToolChain {
+protected:
+  /// \brief Struct to store and manipulate GCC versions.
+  ///
+  /// We rely on assumptions about the form and structure of GCC version
+  /// numbers: they consist of at most three '.'-separated components, and each
+  /// component is a non-negative integer except for the last component. For
+  /// the last component we are very flexible in order to tolerate release
+  /// candidates or 'x' wildcards.
+  ///
+  /// Note that the ordering established among GCCVersions is based on the
+  /// preferred version string to use. For example we prefer versions without
+  /// a hard-coded patch number to those with a hard coded patch number.
+  ///
+  /// Currently this doesn't provide any logic for textual suffixes to patches
+  /// in the way that (for example) Debian's version format does. If that ever
+  /// becomes necessary, it can be added.
+  struct GCCVersion {
+    /// \brief The unparsed text of the version.
+    std::string Text;
+
+    /// \brief The parsed major, minor, and patch numbers.
+    int Major, Minor, Patch;
+
+    /// \brief Any textual suffix on the patch number.
+    std::string PatchSuffix;
+
+    static GCCVersion Parse(StringRef VersionText);
+    bool operator<(const GCCVersion &RHS) const;
+    bool operator>(const GCCVersion &RHS) const { return RHS < *this; }
+    bool operator<=(const GCCVersion &RHS) const { return !(*this > RHS); }
+    bool operator>=(const GCCVersion &RHS) const { return !(*this < RHS); }
+  };
+
+
+  /// \brief This is a class to find a viable GCC installation for Clang to
+  /// use.
+  ///
+  /// This class tries to find a GCC installation on the system, and report
+  /// information about it. It starts from the host information provided to the
+  /// Driver, and has logic for fuzzing that where appropriate.
+  class GCCInstallationDetector {
+
+    bool IsValid;
+    llvm::Triple GCCTriple;
+
+    // FIXME: These might be better as path objects.
+    std::string GCCInstallPath;
+    std::string GCCMultiarchSuffix;
+    std::string GCCParentLibPath;
+
+    GCCVersion Version;
+
+  public:
+    GCCInstallationDetector(const Driver &D, const llvm::Triple &TargetTriple,
+                            const ArgList &Args);
+
+    /// \brief Check whether we detected a valid GCC install.
+    bool isValid() const { return IsValid; }
+
+    /// \brief Get the GCC triple for the detected install.
+    const llvm::Triple &getTriple() const { return GCCTriple; }
+
+    /// \brief Get the detected GCC installation path.
+    StringRef getInstallPath() const { return GCCInstallPath; }
+
+    /// \brief Get the detected GCC installation path suffix for multiarch GCCs.
+    StringRef getMultiarchSuffix() const { return GCCMultiarchSuffix; }
+
+    /// \brief Get the detected GCC parent lib path.
+    StringRef getParentLibPath() const { return GCCParentLibPath; }
+
+    /// \brief Get the detected GCC version string.
+    StringRef getVersion() const { return Version.Text; }
+
+  private:
+    static void CollectLibDirsAndTriples(
+      const llvm::Triple &TargetTriple,
+      const llvm::Triple &MultiarchTriple,
+      SmallVectorImpl<StringRef> &LibDirs,
+      SmallVectorImpl<StringRef> &TripleAliases,
+      SmallVectorImpl<StringRef> &MultiarchLibDirs,
+      SmallVectorImpl<StringRef> &MultiarchTripleAliases);
+
+    void ScanLibDirForGCCTriple(llvm::Triple::ArchType TargetArch,
+                                const std::string &LibDir,
+                                StringRef CandidateTriple,
+                                bool NeedsMultiarchSuffix = false);
+  };
+
+  GCCInstallationDetector GCCInstallation;
+
+  mutable llvm::DenseMap<unsigned, Tool*> Tools;
+
+public:
+  Generic_GCC(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+  ~Generic_GCC();
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual bool IsUnwindTablesDefault() const;
+  virtual const char *GetDefaultRelocationModel() const;
+  virtual const char *GetForcedPicModel() const;
+
+protected:
+  /// \name ToolChain Implementation Helper Functions
+  /// @{
+
+  /// \brief Check whether the target triple's architecture is 64-bits.
+  bool isTarget64Bit() const { return getTriple().isArch64Bit(); }
+
+  /// \brief Check whether the target triple's architecture is 32-bits.
+  bool isTarget32Bit() const { return getTriple().isArch32Bit(); }
+
+  /// @}
+};
+
+class LLVM_LIBRARY_VISIBILITY Hexagon_TC : public ToolChain {
+protected:
+  mutable llvm::DenseMap<unsigned, Tool*> Tools;
+
+public:
+  Hexagon_TC(const Driver &D, const llvm::Triple& Triple);
+  ~Hexagon_TC();
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual bool IsUnwindTablesDefault() const;
+  virtual const char *GetDefaultRelocationModel() const;
+  virtual const char *GetForcedPicModel() const;
+};
+
+  /// Darwin - The base Darwin tool chain.
+class LLVM_LIBRARY_VISIBILITY Darwin : public ToolChain {
+public:
+  /// The host version.
+  unsigned DarwinVersion[3];
+
+private:
+  mutable llvm::DenseMap<unsigned, Tool*> Tools;
+
+  /// Whether the information on the target has been initialized.
+  //
+  // FIXME: This should be eliminated. What we want to do is make this part of
+  // the "default target for arguments" selection process, once we get out of
+  // the argument translation business.
+  mutable bool TargetInitialized;
+
+  // FIXME: Remove this once there is a proper way to detect an ARC runtime
+  // for the simulator.
+ public:
+  mutable enum {
+    ARCSimulator_None,
+    ARCSimulator_HasARCRuntime,
+    ARCSimulator_NoARCRuntime
+  } ARCRuntimeForSimulator;
+
+  mutable enum {
+    LibCXXSimulator_None,
+    LibCXXSimulator_NotAvailable,
+    LibCXXSimulator_Available
+  } LibCXXForSimulator;
+
+private:
+  /// Whether we are targeting iPhoneOS target.
+  mutable bool TargetIsIPhoneOS;
+
+  /// Whether we are targeting the iPhoneOS simulator target.
+  mutable bool TargetIsIPhoneOSSimulator;
+
+  /// The OS version we are targeting.
+  mutable VersionTuple TargetVersion;
+
+  /// The default macosx-version-min of this tool chain; empty until
+  /// initialized.
+  std::string MacosxVersionMin;
+
+  bool hasARCRuntime() const;
+  bool hasSubscriptingRuntime() const;
+
+private:
+  void AddDeploymentTarget(DerivedArgList &Args) const;
+
+public:
+  Darwin(const Driver &D, const llvm::Triple& Triple);
+  ~Darwin();
+
+  std::string ComputeEffectiveClangTriple(const ArgList &Args,
+                                          types::ID InputType) const;
+
+  /// @name Darwin Specific Toolchain API
+  /// {
+
+  // FIXME: Eliminate these ...Target functions and derive separate tool chains
+  // for these targets and put version in constructor.
+  void setTarget(bool IsIPhoneOS, unsigned Major, unsigned Minor,
+                 unsigned Micro, bool IsIOSSim) const {
+    assert((!IsIOSSim || IsIPhoneOS) && "Unexpected deployment target!");
+
+    // FIXME: For now, allow reinitialization as long as values don't
+    // change. This will go away when we move away from argument translation.
+    if (TargetInitialized && TargetIsIPhoneOS == IsIPhoneOS &&
+        TargetIsIPhoneOSSimulator == IsIOSSim &&
+        TargetVersion == VersionTuple(Major, Minor, Micro))
+      return;
+
+    assert(!TargetInitialized && "Target already initialized!");
+    TargetInitialized = true;
+    TargetIsIPhoneOS = IsIPhoneOS;
+    TargetIsIPhoneOSSimulator = IsIOSSim;
+    TargetVersion = VersionTuple(Major, Minor, Micro);
+  }
+
+  bool isTargetIPhoneOS() const {
+    assert(TargetInitialized && "Target not initialized!");
+    return TargetIsIPhoneOS;
+  }
+
+  bool isTargetIOSSimulator() const {
+    assert(TargetInitialized && "Target not initialized!");
+    return TargetIsIPhoneOSSimulator;
+  }
+
+  bool isTargetMacOS() const {
+    return !isTargetIOSSimulator() &&
+           !isTargetIPhoneOS() &&
+           ARCRuntimeForSimulator == ARCSimulator_None;
+  }
+
+  bool isTargetInitialized() const { return TargetInitialized; }
+
+  VersionTuple getTargetVersion() const {
+    assert(TargetInitialized && "Target not initialized!");
+    return TargetVersion;
+  }
+
+  /// getDarwinArchName - Get the "Darwin" arch name for a particular compiler
+  /// invocation. For example, Darwin treats different ARM variations as
+  /// distinct architectures.
+  StringRef getDarwinArchName(const ArgList &Args) const;
+
+  bool isIPhoneOSVersionLT(unsigned V0, unsigned V1=0, unsigned V2=0) const {
+    assert(isTargetIPhoneOS() && "Unexpected call for OS X target!");
+    return TargetVersion < VersionTuple(V0, V1, V2);
+  }
+
+  bool isMacosxVersionLT(unsigned V0, unsigned V1=0, unsigned V2=0) const {
+    assert(!isTargetIPhoneOS() && "Unexpected call for iPhoneOS target!");
+    return TargetVersion < VersionTuple(V0, V1, V2);
+  }
+
+  /// AddLinkSearchPathArgs - Add the linker search paths to \arg CmdArgs.
+  ///
+  /// \param Args - The input argument list.
+  /// \param CmdArgs [out] - The command argument list to append the paths
+  /// (prefixed by -L) to.
+  virtual void AddLinkSearchPathArgs(const ArgList &Args,
+                                     ArgStringList &CmdArgs) const = 0;
+
+  /// AddLinkARCArgs - Add the linker arguments to link the ARC runtime library.
+  virtual void AddLinkARCArgs(const ArgList &Args,
+                              ArgStringList &CmdArgs) const = 0;
+  
+  /// AddLinkRuntimeLibArgs - Add the linker arguments to link the compiler
+  /// runtime library.
+  virtual void AddLinkRuntimeLibArgs(const ArgList &Args,
+                                     ArgStringList &CmdArgs) const = 0;
+  
+  /// }
+  /// @name ToolChain Implementation
+  /// {
+
+  virtual types::ID LookupTypeForExtension(const char *Ext) const;
+
+  virtual bool HasNativeLLVMSupport() const;
+
+  virtual void configureObjCRuntime(ObjCRuntime &runtime) const;
+  virtual bool hasBlocksRuntime() const;
+
+  virtual DerivedArgList *TranslateArgs(const DerivedArgList &Args,
+                                        const char *BoundArch) const;
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual bool IsBlocksDefault() const {
+    // Always allow blocks on Darwin; users interested in versioning are
+    // expected to use /usr/include/Blocks.h.
+    return true;
+  }
+  virtual bool IsIntegratedAssemblerDefault() const {
+#ifdef DISABLE_DEFAULT_INTEGRATED_ASSEMBLER
+    return false;
+#else
+    // Default integrated assembler to on for Darwin.
+    return true;
+#endif
+  }
+  virtual bool IsStrictAliasingDefault() const {
+#ifdef DISABLE_DEFAULT_STRICT_ALIASING
+    return false;
+#else
+    return ToolChain::IsStrictAliasingDefault();
+#endif
+  }
+  
+  virtual bool IsObjCDefaultSynthPropertiesDefault() const {
+    return true;
+  }
+
+  virtual bool IsObjCNonFragileABIDefault() const {
+    // Non-fragile ABI is default for everything but i386.
+    return getTriple().getArch() != llvm::Triple::x86;
+  }
+  virtual bool IsObjCLegacyDispatchDefault() const {
+    // This is only used with the non-fragile ABI.
+
+    // Legacy dispatch is used everywhere except on x86_64.
+    return getTriple().getArch() != llvm::Triple::x86_64;
+  }
+  virtual bool UseObjCMixedDispatch() const {
+    // This is only used with the non-fragile ABI and non-legacy dispatch.
+
+    // Mixed dispatch is used everywhere except OS X before 10.6.
+    return !(!isTargetIPhoneOS() && isMacosxVersionLT(10, 6));
+  }
+  virtual bool IsUnwindTablesDefault() const;
+  virtual unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const {
+    // Stack protectors default to on for user code on 10.5,
+    // and for everything in 10.6 and beyond
+    return isTargetIPhoneOS() ||
+      (!isMacosxVersionLT(10, 6) ||
+         (!isMacosxVersionLT(10, 5) && !KernelOrKext));
+  }
+  virtual RuntimeLibType GetDefaultRuntimeLibType() const {
+    return ToolChain::RLT_CompilerRT;
+  }
+  virtual const char *GetDefaultRelocationModel() const;
+  virtual const char *GetForcedPicModel() const;
+
+  virtual bool SupportsProfiling() const;
+
+  virtual bool SupportsObjCGC() const;
+
+  virtual bool SupportsObjCARC() const;
+
+  virtual bool UseDwarfDebugFlags() const;
+
+  virtual bool UseSjLjExceptions() const;
+
+  /// }
+};
+
+/// DarwinClang - The Darwin toolchain used by Clang.
+class LLVM_LIBRARY_VISIBILITY DarwinClang : public Darwin {
+private:
+  void AddGCCLibexecPath(unsigned darwinVersion);
+
+public:
+  DarwinClang(const Driver &D, const llvm::Triple& Triple);
+
+  /// @name Darwin ToolChain Implementation
+  /// {
+
+  virtual void AddLinkSearchPathArgs(const ArgList &Args,
+                                    ArgStringList &CmdArgs) const;
+
+  virtual void AddLinkRuntimeLibArgs(const ArgList &Args,
+                                     ArgStringList &CmdArgs) const;
+  void AddLinkRuntimeLib(const ArgList &Args, ArgStringList &CmdArgs, 
+                         const char *DarwinStaticLib) const;
+  
+  virtual void AddCXXStdlibLibArgs(const ArgList &Args,
+                                   ArgStringList &CmdArgs) const;
+
+  virtual void AddCCKextLibArgs(const ArgList &Args,
+                                ArgStringList &CmdArgs) const;
+
+  virtual void AddLinkARCArgs(const ArgList &Args,
+                              ArgStringList &CmdArgs) const;
+  /// }
+};
+
+/// Darwin_Generic_GCC - Generic Darwin tool chain using gcc.
+class LLVM_LIBRARY_VISIBILITY Darwin_Generic_GCC : public Generic_GCC {
+public:
+  Darwin_Generic_GCC(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+    : Generic_GCC(D, Triple, Args) {}
+
+  std::string ComputeEffectiveClangTriple(const ArgList &Args,
+                                          types::ID InputType) const;
+
+  virtual const char *GetDefaultRelocationModel() const { return "pic"; }
+};
+
+class LLVM_LIBRARY_VISIBILITY Generic_ELF : public Generic_GCC {
+  virtual void anchor();
+public:
+  Generic_ELF(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
+    : Generic_GCC(D, Triple, Args) {}
+
+  virtual bool IsIntegratedAssemblerDefault() const {
+    // Default integrated assembler to on for x86.
+    return (getTriple().getArch() == llvm::Triple::x86 ||
+            getTriple().getArch() == llvm::Triple::x86_64);
+  }
+};
+
+class LLVM_LIBRARY_VISIBILITY AuroraUX : public Generic_GCC {
+public:
+  AuroraUX(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY Solaris : public Generic_GCC {
+public:
+  Solaris(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual bool IsIntegratedAssemblerDefault() const { return true; }
+};
+
+
+class LLVM_LIBRARY_VISIBILITY OpenBSD : public Generic_ELF {
+public:
+  OpenBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual bool IsObjCNonFragileABIDefault() const { return true; }
+  virtual bool IsObjCLegacyDispatchDefault() const {
+    llvm::Triple::ArchType Arch = getTriple().getArch();
+    if (Arch == llvm::Triple::arm ||
+        Arch == llvm::Triple::x86 ||
+        Arch == llvm::Triple::x86_64)
+     return false;
+    return true;
+  }
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY FreeBSD : public Generic_ELF {
+public:
+  FreeBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual bool IsObjCNonFragileABIDefault() const { return true; }
+  virtual bool IsObjCLegacyDispatchDefault() const {
+    llvm::Triple::ArchType Arch = getTriple().getArch();
+    if (Arch == llvm::Triple::arm ||
+        Arch == llvm::Triple::x86 ||
+        Arch == llvm::Triple::x86_64)
+     return false;
+    return true;
+  }
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY NetBSD : public Generic_ELF {
+public:
+  NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual bool IsObjCNonFragileABIDefault() const { return true; }
+  virtual bool IsObjCLegacyDispatchDefault() const {
+    llvm::Triple::ArchType Arch = getTriple().getArch();
+    if (Arch == llvm::Triple::arm ||
+        Arch == llvm::Triple::x86 ||
+        Arch == llvm::Triple::x86_64)
+     return false;
+    return true;
+  }
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY Minix : public Generic_ELF {
+public:
+  Minix(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY DragonFly : public Generic_ELF {
+public:
+  DragonFly(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+};
+
+class LLVM_LIBRARY_VISIBILITY Linux : public Generic_ELF {
+public:
+  Linux(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
+
+  virtual bool HasNativeLLVMSupport() const;
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual void AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                         ArgStringList &CC1Args) const;
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
+
+  std::string Linker;
+  std::vector<std::string> ExtraOpts;
+
+private:
+  static bool addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,
+                                       const ArgList &DriverArgs,
+                                       ArgStringList &CC1Args);
+};
+
+
+/// TCEToolChain - A tool chain using the llvm bitcode tools to perform
+/// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
+class LLVM_LIBRARY_VISIBILITY TCEToolChain : public ToolChain {
+public:
+  TCEToolChain(const Driver &D, const llvm::Triple& Triple);
+  ~TCEToolChain();
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+  bool IsMathErrnoDefault() const;
+  bool IsUnwindTablesDefault() const;
+  const char* GetDefaultRelocationModel() const;
+  const char* GetForcedPicModel() const;
+
+private:
+  mutable llvm::DenseMap<unsigned, Tool*> Tools;
+
+};
+
+class LLVM_LIBRARY_VISIBILITY Windows : public ToolChain {
+  mutable llvm::DenseMap<unsigned, Tool*> Tools;
+
+public:
+  Windows(const Driver &D, const llvm::Triple& Triple);
+
+  virtual Tool &SelectTool(const Compilation &C, const JobAction &JA,
+                           const ActionList &Inputs) const;
+
+  virtual bool IsIntegratedAssemblerDefault() const;
+  virtual bool IsUnwindTablesDefault() const;
+  virtual const char *GetDefaultRelocationModel() const;
+  virtual const char *GetForcedPicModel() const;
+
+  virtual void AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                         ArgStringList &CC1Args) const;
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
+
+};
+
+} // end namespace toolchains
+} // end namespace driver
+} // end namespace clang
+
+#endif
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
new file mode 100644
index 0000000..47b5294
--- /dev/null
+++ b/clang/lib/Driver/Tools.cpp
@@ -0,0 +1,5589 @@
+//===--- Tools.cpp - Tools Implementations --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Tools.h"
+
+#include "clang/Driver/Action.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Job.h"
+#include "clang/Driver/ObjCRuntime.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/ToolChain.h"
+#include "clang/Driver/Util.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Process.h"
+#include "llvm/Support/ErrorHandling.h"
+
+#include "InputInfo.h"
+#include "ToolChains.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+
+/// CheckPreprocessingOptions - Perform some validation of preprocessing
+/// arguments that is shared with gcc.
+static void CheckPreprocessingOptions(const Driver &D, const ArgList &Args) {
+  if (Arg *A = Args.getLastArg(options::OPT_C, options::OPT_CC))
+    if (!Args.hasArg(options::OPT_E) && !D.CCCIsCPP)
+      D.Diag(diag::err_drv_argument_only_allowed_with)
+        << A->getAsString(Args) << "-E";
+}
+
+/// CheckCodeGenerationOptions - Perform some validation of code generation
+/// arguments that is shared with gcc.
+static void CheckCodeGenerationOptions(const Driver &D, const ArgList &Args) {
+  // In gcc, only ARM checks this, but it seems reasonable to check universally.
+  if (Args.hasArg(options::OPT_static))
+    if (const Arg *A = Args.getLastArg(options::OPT_dynamic,
+                                       options::OPT_mdynamic_no_pic))
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+        << A->getAsString(Args) << "-static";
+}
+
+// Quote target names for inclusion in GNU Make dependency files.
+// Only the characters '$', '#', ' ', '\t' are quoted.
+static void QuoteTarget(StringRef Target,
+                        SmallVectorImpl<char> &Res) {
+  for (unsigned i = 0, e = Target.size(); i != e; ++i) {
+    switch (Target[i]) {
+    case ' ':
+    case '\t':
+      // Escape the preceding backslashes
+      for (int j = i - 1; j >= 0 && Target[j] == '\\'; --j)
+        Res.push_back('\\');
+
+      // Escape the space/tab
+      Res.push_back('\\');
+      break;
+    case '$':
+      Res.push_back('$');
+      break;
+    case '#':
+      Res.push_back('\\');
+      break;
+    default:
+      break;
+    }
+
+    Res.push_back(Target[i]);
+  }
+}
+
+static void addDirectoryList(const ArgList &Args,
+                             ArgStringList &CmdArgs,
+                             const char *ArgName,
+                             const char *EnvVar) {
+  const char *DirList = ::getenv(EnvVar);
+  if (!DirList)
+    return; // Nothing to do.
+
+  StringRef Dirs(DirList);
+  if (Dirs.empty()) // Empty string should not add '.'.
+    return;
+
+  StringRef::size_type Delim;
+  while ((Delim = Dirs.find(llvm::sys::PathSeparator)) != StringRef::npos) {
+    if (Delim == 0) { // Leading colon.
+      CmdArgs.push_back(ArgName);
+      CmdArgs.push_back(".");
+    } else {
+      CmdArgs.push_back(ArgName);
+      CmdArgs.push_back(Args.MakeArgString(Dirs.substr(0, Delim)));
+    }
+    Dirs = Dirs.substr(Delim + 1);
+  }
+
+  if (Dirs.empty()) { // Trailing colon.
+    CmdArgs.push_back(ArgName);
+    CmdArgs.push_back(".");
+  } else { // Add the last path.
+    CmdArgs.push_back(ArgName);
+    CmdArgs.push_back(Args.MakeArgString(Dirs));
+  }
+}
+
+static void AddLinkerInputs(const ToolChain &TC,
+                            const InputInfoList &Inputs, const ArgList &Args,
+                            ArgStringList &CmdArgs) {
+  const Driver &D = TC.getDriver();
+
+  // Add extra linker input arguments which are not treated as inputs
+  // (constructed via -Xarch_).
+  Args.AddAllArgValues(CmdArgs, options::OPT_Zlinker_input);
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+
+    if (!TC.HasNativeLLVMSupport()) {
+      // Don't try to pass LLVM inputs unless we have native support.
+      if (II.getType() == types::TY_LLVM_IR ||
+          II.getType() == types::TY_LTO_IR ||
+          II.getType() == types::TY_LLVM_BC ||
+          II.getType() == types::TY_LTO_BC)
+        D.Diag(diag::err_drv_no_linker_llvm_support)
+          << TC.getTripleString();
+    }
+
+    // Add filenames immediately.
+    if (II.isFilename()) {
+      CmdArgs.push_back(II.getFilename());
+      continue;
+    }
+
+    // Otherwise, this is a linker input argument.
+    const Arg &A = II.getInputArg();
+
+    // Handle reserved library options.
+    if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx)) {
+      TC.AddCXXStdlibLibArgs(Args, CmdArgs);
+    } else if (A.getOption().matches(options::OPT_Z_reserved_lib_cckext)) {
+      TC.AddCCKextLibArgs(Args, CmdArgs);
+    } else
+      A.renderAsInput(Args, CmdArgs);
+  }
+
+  // LIBRARY_PATH - included following the user specified library paths.
+  addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");
+}
+
+/// \brief Determine whether Objective-C automated reference counting is
+/// enabled.
+static bool isObjCAutoRefCount(const ArgList &Args) {
+  return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
+}
+
+/// \brief Determine whether we are linking the ObjC runtime.
+static bool isObjCRuntimeLinked(const ArgList &Args) {
+  if (isObjCAutoRefCount(Args))
+    return true;
+  return Args.hasArg(options::OPT_fobjc_link_runtime);
+}
+
+static void addProfileRT(const ToolChain &TC, const ArgList &Args,
+                         ArgStringList &CmdArgs,
+                         llvm::Triple Triple) {
+  if (!(Args.hasArg(options::OPT_fprofile_arcs) ||
+        Args.hasArg(options::OPT_fprofile_generate) ||
+        Args.hasArg(options::OPT_fcreate_profile) ||
+        Args.hasArg(options::OPT_coverage)))
+    return;
+
+  // GCC links libgcov.a by adding -L<inst>/gcc/lib/gcc/<triple>/<ver> -lgcov to
+  // the link line. We cannot do the same thing because unlike gcov there is a
+  // libprofile_rt.so. We used to use the -l:libprofile_rt.a syntax, but that is
+  // not supported by old linkers.
+  std::string ProfileRT =
+    std::string(TC.getDriver().Dir) + "/../lib/libprofile_rt.a";
+
+  CmdArgs.push_back(Args.MakeArgString(ProfileRT));
+}
+
+void Clang::AddPreprocessingOptions(Compilation &C,
+                                    const Driver &D,
+                                    const ArgList &Args,
+                                    ArgStringList &CmdArgs,
+                                    const InputInfo &Output,
+                                    const InputInfoList &Inputs) const {
+  Arg *A;
+
+  CheckPreprocessingOptions(D, Args);
+
+  Args.AddLastArg(CmdArgs, options::OPT_C);
+  Args.AddLastArg(CmdArgs, options::OPT_CC);
+
+  // Handle dependency file generation.
+  if ((A = Args.getLastArg(options::OPT_M, options::OPT_MM)) ||
+      (A = Args.getLastArg(options::OPT_MD)) ||
+      (A = Args.getLastArg(options::OPT_MMD))) {
+    // Determine the output location.
+    const char *DepFile;
+    if (Output.getType() == types::TY_Dependencies) {
+      DepFile = Output.getFilename();
+    } else if (Arg *MF = Args.getLastArg(options::OPT_MF)) {
+      DepFile = MF->getValue(Args);
+      C.addFailureResultFile(DepFile);
+    } else if (A->getOption().matches(options::OPT_M) ||
+               A->getOption().matches(options::OPT_MM)) {
+      DepFile = "-";
+    } else {
+      DepFile = darwin::CC1::getDependencyFileName(Args, Inputs);
+      C.addFailureResultFile(DepFile);
+    }
+    CmdArgs.push_back("-dependency-file");
+    CmdArgs.push_back(DepFile);
+
+    // Add a default target if one wasn't specified.
+    if (!Args.hasArg(options::OPT_MT) && !Args.hasArg(options::OPT_MQ)) {
+      const char *DepTarget;
+
+      // If user provided -o, that is the dependency target, except
+      // when we are only generating a dependency file.
+      Arg *OutputOpt = Args.getLastArg(options::OPT_o);
+      if (OutputOpt && Output.getType() != types::TY_Dependencies) {
+        DepTarget = OutputOpt->getValue(Args);
+      } else {
+        // Otherwise derive from the base input.
+        //
+        // FIXME: This should use the computed output file location.
+        SmallString<128> P(Inputs[0].getBaseInput());
+        llvm::sys::path::replace_extension(P, "o");
+        DepTarget = Args.MakeArgString(llvm::sys::path::filename(P));
+      }
+
+      CmdArgs.push_back("-MT");
+      SmallString<128> Quoted;
+      QuoteTarget(DepTarget, Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
+    }
+
+    if (A->getOption().matches(options::OPT_M) ||
+        A->getOption().matches(options::OPT_MD))
+      CmdArgs.push_back("-sys-header-deps");
+  }
+
+  if (Args.hasArg(options::OPT_MG)) {
+    if (!A || A->getOption().matches(options::OPT_MD) ||
+              A->getOption().matches(options::OPT_MMD))
+      D.Diag(diag::err_drv_mg_requires_m_or_mm);
+    CmdArgs.push_back("-MG");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_MP);
+
+  // Convert all -MQ <target> args to -MT <quoted target>
+  for (arg_iterator it = Args.filtered_begin(options::OPT_MT,
+                                             options::OPT_MQ),
+         ie = Args.filtered_end(); it != ie; ++it) {
+    const Arg *A = *it;
+    A->claim();
+
+    if (A->getOption().matches(options::OPT_MQ)) {
+      CmdArgs.push_back("-MT");
+      SmallString<128> Quoted;
+      QuoteTarget(A->getValue(Args), Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
+
+    // -MT flag - no change
+    } else {
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  // Add -i* options, and automatically translate to
+  // -include-pch/-include-pth for transparent PCH support. It's
+  // wonky, but we include looking for .gch so we can support seamless
+  // replacement into a build system already set up to be generating
+  // .gch files.
+  bool RenderedImplicitInclude = false;
+  for (arg_iterator it = Args.filtered_begin(options::OPT_clang_i_Group),
+         ie = Args.filtered_end(); it != ie; ++it) {
+    const Arg *A = it;
+
+    if (A->getOption().matches(options::OPT_include)) {
+      bool IsFirstImplicitInclude = !RenderedImplicitInclude;
+      RenderedImplicitInclude = true;
+
+      // Use PCH if the user requested it.
+      bool UsePCH = D.CCCUsePCH;
+
+      bool FoundPTH = false;
+      bool FoundPCH = false;
+      llvm::sys::Path P(A->getValue(Args));
+      bool Exists;
+      if (UsePCH) {
+        P.appendSuffix("pch");
+        if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+          FoundPCH = true;
+        else
+          P.eraseSuffix();
+      }
+
+      if (!FoundPCH) {
+        P.appendSuffix("pth");
+        if (!llvm::sys::fs::exists(P.str(), Exists) && Exists)
+          FoundPTH = true;
+        else
+          P.eraseSuffix();
+      }
+
+      if (!FoundPCH && !FoundPTH) {
+        P.appendSuffix("gch");
+        if (!llvm::sys::fs::exists(P.str(), Exists) && Exists) {
+          FoundPCH = UsePCH;
+          FoundPTH = !UsePCH;
+        }
+        else
+          P.eraseSuffix();
+      }
+
+      if (FoundPCH || FoundPTH) {
+        if (IsFirstImplicitInclude) {
+          A->claim();
+          if (UsePCH)
+            CmdArgs.push_back("-include-pch");
+          else
+            CmdArgs.push_back("-include-pth");
+          CmdArgs.push_back(Args.MakeArgString(P.str()));
+          continue;
+        } else {
+          // Ignore the PCH if not first on command line and emit warning.
+          D.Diag(diag::warn_drv_pch_not_first_include)
+              << P.str() << A->getAsString(Args);
+        }
+      }
+    }
+
+    // Not translated, render as usual.
+    A->claim();
+    A->render(Args, CmdArgs);
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_D, options::OPT_U);
+  Args.AddAllArgs(CmdArgs, options::OPT_I_Group, options::OPT_F,
+                  options::OPT_index_header_map);
+
+  // Add -Wp, and -Xassembler if using the preprocessor.
+
+  // FIXME: There is a very unfortunate problem here, some troubled
+  // souls abuse -Wp, to pass preprocessor options in gcc syntax. To
+  // really support that we would have to parse and then translate
+  // those options. :(
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wp_COMMA,
+                       options::OPT_Xpreprocessor);
+
+  // -I- is a deprecated GCC feature, reject it.
+  if (Arg *A = Args.getLastArg(options::OPT_I_))
+    D.Diag(diag::err_drv_I_dash_not_supported) << A->getAsString(Args);
+
+  // If we have a --sysroot, and don't have an explicit -isysroot flag, add an
+  // -isysroot to the CC1 invocation.
+  StringRef sysroot = C.getSysRoot();
+  if (sysroot != "") {
+    if (!Args.hasArg(options::OPT_isysroot)) {
+      CmdArgs.push_back("-isysroot");
+      CmdArgs.push_back(C.getArgs().MakeArgString(sysroot));
+    }
+  }
+  
+  // If a module path was provided, pass it along. Otherwise, use a temporary
+  // directory.
+  if (Arg *A = Args.getLastArg(options::OPT_fmodule_cache_path)) {
+    A->claim();
+    A->render(Args, CmdArgs);
+  } else {
+    SmallString<128> DefaultModuleCache;
+    llvm::sys::path::system_temp_directory(/*erasedOnReboot=*/false, 
+                                           DefaultModuleCache);
+    llvm::sys::path::append(DefaultModuleCache, "clang-module-cache");
+    CmdArgs.push_back("-fmodule-cache-path");
+    CmdArgs.push_back(Args.MakeArgString(DefaultModuleCache));
+  }
+  
+  // Parse additional include paths from environment variables.
+  // FIXME: We should probably sink the logic for handling these from the
+  // frontend into the driver. It will allow deleting 4 otherwise unused flags.
+  // CPATH - included following the user specified includes (but prior to
+  // builtin and standard includes).
+  addDirectoryList(Args, CmdArgs, "-I", "CPATH");
+  // C_INCLUDE_PATH - system includes enabled when compiling C.
+  addDirectoryList(Args, CmdArgs, "-c-isystem", "C_INCLUDE_PATH");
+  // CPLUS_INCLUDE_PATH - system includes enabled when compiling C++.
+  addDirectoryList(Args, CmdArgs, "-cxx-isystem", "CPLUS_INCLUDE_PATH");
+  // OBJC_INCLUDE_PATH - system includes enabled when compiling ObjC.
+  addDirectoryList(Args, CmdArgs, "-objc-isystem", "OBJC_INCLUDE_PATH");
+  // OBJCPLUS_INCLUDE_PATH - system includes enabled when compiling ObjC++.
+  addDirectoryList(Args, CmdArgs, "-objcxx-isystem", "OBJCPLUS_INCLUDE_PATH");
+
+  // Add C++ include arguments, if needed.
+  if (types::isCXX(Inputs[0].getType()))
+    getToolChain().AddClangCXXStdlibIncludeArgs(Args, CmdArgs);
+
+  // Add system include arguments.
+  getToolChain().AddClangSystemIncludeArgs(Args, CmdArgs);
+}
+
+/// getARMTargetCPU - Get the (LLVM) name of the ARM cpu we are targeting.
+//
+// FIXME: tblgen this.
+static const char *getARMTargetCPU(const ArgList &Args,
+                                   const llvm::Triple &Triple) {
+  // FIXME: Warn on inconsistent use of -mcpu and -march.
+
+  // If we have -mcpu=, use that.
+  if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
+    return A->getValue(Args);
+
+  StringRef MArch;
+  if (Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+    // Otherwise, if we have -march= choose the base CPU for that arch.
+    MArch = A->getValue(Args);
+  } else {
+    // Otherwise, use the Arch from the triple.
+    MArch = Triple.getArchName();
+  }
+
+  return llvm::StringSwitch<const char *>(MArch)
+    .Cases("armv2", "armv2a","arm2")
+    .Case("armv3", "arm6")
+    .Case("armv3m", "arm7m")
+    .Cases("armv4", "armv4t", "arm7tdmi")
+    .Cases("armv5", "armv5t", "arm10tdmi")
+    .Cases("armv5e", "armv5te", "arm1026ejs")
+    .Case("armv5tej", "arm926ej-s")
+    .Cases("armv6", "armv6k", "arm1136jf-s")
+    .Case("armv6j", "arm1136j-s")
+    .Cases("armv6z", "armv6zk", "arm1176jzf-s")
+    .Case("armv6t2", "arm1156t2-s")
+    .Cases("armv7", "armv7a", "armv7-a", "cortex-a8")
+    .Cases("armv7r", "armv7-r", "cortex-r4")
+    .Cases("armv7m", "armv7-m", "cortex-m3")
+    .Case("ep9312", "ep9312")
+    .Case("iwmmxt", "iwmmxt")
+    .Case("xscale", "xscale")
+    .Cases("armv6m", "armv6-m", "cortex-m0")
+    // If all else failed, return the most base CPU LLVM supports.
+    .Default("arm7tdmi");
+}
+
+/// getLLVMArchSuffixForARM - Get the LLVM arch name to use for a particular
+/// CPU.
+//
+// FIXME: This is redundant with -mcpu, why does LLVM use this.
+// FIXME: tblgen this, or kill it!
+static const char *getLLVMArchSuffixForARM(StringRef CPU) {
+  return llvm::StringSwitch<const char *>(CPU)
+    .Cases("arm7tdmi", "arm7tdmi-s", "arm710t", "v4t")
+    .Cases("arm720t", "arm9", "arm9tdmi", "v4t")
+    .Cases("arm920", "arm920t", "arm922t", "v4t")
+    .Cases("arm940t", "ep9312","v4t")
+    .Cases("arm10tdmi",  "arm1020t", "v5")
+    .Cases("arm9e",  "arm926ej-s",  "arm946e-s", "v5e")
+    .Cases("arm966e-s",  "arm968e-s",  "arm10e", "v5e")
+    .Cases("arm1020e",  "arm1022e",  "xscale", "iwmmxt", "v5e")
+    .Cases("arm1136j-s",  "arm1136jf-s",  "arm1176jz-s", "v6")
+    .Cases("arm1176jzf-s",  "mpcorenovfp",  "mpcore", "v6")
+    .Cases("arm1156t2-s",  "arm1156t2f-s", "v6t2")
+    .Cases("cortex-a8", "cortex-a9", "v7")
+    .Case("cortex-m3", "v7m")
+    .Case("cortex-m4", "v7m")
+    .Case("cortex-m0", "v6m")
+    .Default("");
+}
+
+// FIXME: Move to target hook.
+static bool isSignedCharDefault(const llvm::Triple &Triple) {
+  switch (Triple.getArch()) {
+  default:
+    return true;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+    if (Triple.isOSDarwin())
+      return true;
+    return false;
+  }
+}
+
+// Handle -mfpu=.
+//
+// FIXME: Centralize feature selection, defaulting shouldn't be also in the
+// frontend target.
+static void addFPUArgs(const Driver &D, const Arg *A, const ArgList &Args,
+                       ArgStringList &CmdArgs) {
+  StringRef FPU = A->getValue(Args);
+
+  // Set the target features based on the FPU.
+  if (FPU == "fpa" || FPU == "fpe2" || FPU == "fpe3" || FPU == "maverick") {
+    // Disable any default FPU support.
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-vfp2");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-vfp3");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neon");
+  } else if (FPU == "vfp3-d16" || FPU == "vfpv3-d16") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+vfp3");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+d16");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neon");
+  } else if (FPU == "vfp") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+vfp2");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neon");
+  } else if (FPU == "vfp3" || FPU == "vfpv3") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+vfp3");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neon");
+  } else if (FPU == "neon") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+neon");
+  } else
+    D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+// Handle -mfpmath=.
+static void addFPMathArgs(const Driver &D, const Arg *A, const ArgList &Args,
+                          ArgStringList &CmdArgs, StringRef CPU) {
+  StringRef FPMath = A->getValue(Args);
+  
+  // Set the target features based on the FPMath.
+  if (FPMath == "neon") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+neonfp");
+    
+    if (CPU != "cortex-a8" && CPU != "cortex-a9" && CPU != "cortex-a9-mp")    
+      D.Diag(diag::err_drv_invalid_feature) << "-mfpmath=neon" << CPU;
+    
+  } else if (FPMath == "vfp" || FPMath == "vfp2" || FPMath == "vfp3" ||
+             FPMath == "vfp4") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neonfp");
+
+    // FIXME: Add warnings when disabling a feature not present for a given CPU.    
+  } else
+    D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+// Select the float ABI as determined by -msoft-float, -mhard-float, and
+// -mfloat-abi=.
+static StringRef getARMFloatABI(const Driver &D,
+                                const ArgList &Args,
+                                const llvm::Triple &Triple) {
+  StringRef FloatABI;
+  if (Arg *A = Args.getLastArg(options::OPT_msoft_float,
+                               options::OPT_mhard_float,
+                               options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(options::OPT_msoft_float))
+      FloatABI = "soft";
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      FloatABI = "hard";
+    else {
+      FloatABI = A->getValue(Args);
+      if (FloatABI != "soft" && FloatABI != "softfp" && FloatABI != "hard") {
+        D.Diag(diag::err_drv_invalid_mfloat_abi)
+          << A->getAsString(Args);
+        FloatABI = "soft";
+      }
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (FloatABI.empty()) {
+    switch (Triple.getOS()) {
+    case llvm::Triple::Darwin:
+    case llvm::Triple::MacOSX:
+    case llvm::Triple::IOS: {
+      // Darwin defaults to "softfp" for v6 and v7.
+      //
+      // FIXME: Factor out an ARM class so we can cache the arch somewhere.
+      StringRef ArchName =
+        getLLVMArchSuffixForARM(getARMTargetCPU(Args, Triple));
+      if (ArchName.startswith("v6") || ArchName.startswith("v7"))
+        FloatABI = "softfp";
+      else
+        FloatABI = "soft";
+      break;
+    }
+
+    case llvm::Triple::Linux: {
+      if (Triple.getEnvironment() == llvm::Triple::GNUEABI) {
+        FloatABI = "softfp";
+        break;
+      }
+    }
+    // fall through
+
+    default:
+      switch(Triple.getEnvironment()) {
+      case llvm::Triple::GNUEABI:
+        FloatABI = "softfp";
+        break;
+      case llvm::Triple::EABI:
+        // EABI is always AAPCS, and if it was not marked 'hard', it's softfp
+        FloatABI = "softfp";
+        break;
+      case llvm::Triple::ANDROIDEABI: {
+        StringRef ArchName =
+          getLLVMArchSuffixForARM(getARMTargetCPU(Args, Triple));
+        if (ArchName.startswith("v7"))
+          FloatABI = "softfp";
+        else
+          FloatABI = "soft";
+        break;
+      }
+      default:
+        // Assume "soft", but warn the user we are guessing.
+        FloatABI = "soft";
+        D.Diag(diag::warn_drv_assuming_mfloat_abi_is) << "soft";
+        break;
+      }
+    }
+  }
+
+  return FloatABI;
+}
+
+
+void Clang::AddARMTargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs,
+                             bool KernelOrKext) const {
+  const Driver &D = getToolChain().getDriver();
+  llvm::Triple Triple = getToolChain().getTriple();
+
+  // Select the ABI to use.
+  //
+  // FIXME: Support -meabi.
+  const char *ABIName = 0;
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
+    ABIName = A->getValue(Args);
+  } else {
+    // Select the default based on the platform.
+    switch(Triple.getEnvironment()) {
+    case llvm::Triple::ANDROIDEABI:
+    case llvm::Triple::GNUEABI:
+      ABIName = "aapcs-linux";
+      break;
+    case llvm::Triple::EABI:
+      ABIName = "aapcs";
+      break;
+    default:
+      ABIName = "apcs-gnu";
+    }
+  }
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName);
+
+  // Set the CPU based on -march= and -mcpu=.
+  CmdArgs.push_back("-target-cpu");
+  CmdArgs.push_back(getARMTargetCPU(Args, Triple));
+
+  // Determine floating point ABI from the options & target defaults.
+  StringRef FloatABI = getARMFloatABI(D, Args, Triple);
+  if (FloatABI == "soft") {
+    // Floating point operations and argument passing are soft.
+    //
+    // FIXME: This changes CPP defines, we need -target-soft-float.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else if (FloatABI == "softfp") {
+    // Floating point operations are hard, but argument passing is soft.
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else {
+    // Floating point operations and argument passing are hard.
+    assert(FloatABI == "hard" && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+
+  // Set appropriate target features for floating point mode.
+  //
+  // FIXME: Note, this is a hack, the LLVM backend doesn't actually use these
+  // yet (it uses the -mfloat-abi and -msoft-float options above), and it is
+  // stripped out by the ARM target.
+
+  // Use software floating point operations?
+  if (FloatABI == "soft") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+soft-float");
+  }
+
+  // Use software floating point argument passing?
+  if (FloatABI != "hard") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+soft-float-abi");
+  }
+
+  // Honor -mfpu=.
+  if (const Arg *A = Args.getLastArg(options::OPT_mfpu_EQ))
+    addFPUArgs(D, A, Args, CmdArgs);
+
+  // Honor -mfpmath=.
+  if (const Arg *A = Args.getLastArg(options::OPT_mfpmath_EQ))
+    addFPMathArgs(D, A, Args, CmdArgs, getARMTargetCPU(Args, Triple));
+
+  // Setting -msoft-float effectively disables NEON because of the GCC
+  // implementation, although the same isn't true of VFP or VFP3.
+  if (FloatABI == "soft") {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("-neon");
+  }
+
+  // Kernel code has more strict alignment requirements.
+  if (KernelOrKext) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-arm-long-calls");
+
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-arm-strict-align");
+
+    // The kext linker doesn't know how to deal with movw/movt.
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-arm-darwin-use-movt=0");
+  }
+
+  // Setting -mno-global-merge disables the codegen global merge pass. Setting 
+  // -mglobal-merge has no effect as the pass is enabled by default.
+  if (Arg *A = Args.getLastArg(options::OPT_mglobal_merge,
+                               options::OPT_mno_global_merge)) {
+    if (A->getOption().matches(options::OPT_mno_global_merge))
+      CmdArgs.push_back("-mno-global-merge");
+  }
+}
+
+// Get default architecture.
+static const char* getMipsArchFromCPU(StringRef CPUName) {
+  if (CPUName == "mips32" || CPUName == "mips32r2")
+    return "mips";
+
+  assert((CPUName == "mips64" || CPUName == "mips64r2") &&
+         "Unexpected cpu name.");
+
+  return "mips64";
+}
+
+// Check that ArchName is a known Mips architecture name.
+static bool checkMipsArchName(StringRef ArchName) {
+  return ArchName == "mips" ||
+         ArchName == "mipsel" ||
+         ArchName == "mips64" ||
+         ArchName == "mips64el";
+}
+
+// Get default target cpu.
+static const char* getMipsCPUFromArch(StringRef ArchName) {
+  if (ArchName == "mips" || ArchName == "mipsel")
+    return "mips32";
+
+  assert((ArchName == "mips64" || ArchName == "mips64el") &&
+         "Unexpected arch name.");
+
+  return "mips64";
+}
+
+// Get default ABI.
+static const char* getMipsABIFromArch(StringRef ArchName) {
+    if (ArchName == "mips" || ArchName == "mipsel")
+      return "o32";
+    
+    assert((ArchName == "mips64" || ArchName == "mips64el") &&
+           "Unexpected arch name.");
+    return "n64";
+}
+
+// Get CPU and ABI names. They are not independent
+// so we have to calculate them together.
+static void getMipsCPUAndABI(const ArgList &Args,
+                             const ToolChain &TC,
+                             StringRef &CPUName,
+                             StringRef &ABIName) {
+  StringRef ArchName;
+
+  // Select target cpu and architecture.
+  if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
+    CPUName = A->getValue(Args);
+    ArchName = getMipsArchFromCPU(CPUName);
+  }
+  else {
+    ArchName = Args.MakeArgString(TC.getArchName());
+    if (!checkMipsArchName(ArchName))
+      TC.getDriver().Diag(diag::err_drv_invalid_arch_name) << ArchName;
+    else
+      CPUName = getMipsCPUFromArch(ArchName);
+  }
+ 
+  // Select the ABI to use.
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
+    ABIName = A->getValue(Args);
+  else 
+    ABIName = getMipsABIFromArch(ArchName);
+}
+
+void Clang::AddMIPSTargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+  StringRef CPUName;
+  StringRef ABIName;
+  getMipsCPUAndABI(Args, getToolChain(), CPUName, ABIName);
+
+  CmdArgs.push_back("-target-cpu");
+  CmdArgs.push_back(CPUName.data());
+
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName.data());
+
+  // Select the float ABI as determined by -msoft-float, -mhard-float,
+  // and -mfloat-abi=.
+  StringRef FloatABI;
+  if (Arg *A = Args.getLastArg(options::OPT_msoft_float,
+                               options::OPT_mhard_float,
+                               options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(options::OPT_msoft_float))
+      FloatABI = "soft";
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      FloatABI = "hard";
+    else {
+      FloatABI = A->getValue(Args);
+      if (FloatABI != "soft" && FloatABI != "single" && FloatABI != "hard") {
+        D.Diag(diag::err_drv_invalid_mfloat_abi)
+          << A->getAsString(Args);
+        FloatABI = "hard";
+      }
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (FloatABI.empty()) {
+    // Assume "hard", because it's a default value used by gcc.
+    // When we start to recognize specific target MIPS processors,
+    // we will be able to select the default more correctly.
+    FloatABI = "hard";
+  }
+
+  if (FloatABI == "soft") {
+    // Floating point operations and argument passing are soft.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+
+    // FIXME: Note, this is a hack. We need to pass the selected float
+    // mode to the MipsTargetInfoBase to define appropriate macros there.
+    // Now it is the only method.
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+soft-float");
+  }
+  else if (FloatABI == "single") {
+    // Restrict the use of hardware floating-point
+    // instructions to 32-bit operations.
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+single-float");
+  }
+  else {
+    // Floating point operations and argument passing are hard.
+    assert(FloatABI == "hard" && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+}
+
+void Clang::AddSparcTargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  if (const Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+    CmdArgs.push_back("-target-cpu");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  // Select the float ABI as determined by -msoft-float, -mhard-float, and
+  StringRef FloatABI;
+  if (Arg *A = Args.getLastArg(options::OPT_msoft_float,
+                               options::OPT_mhard_float)) {
+    if (A->getOption().matches(options::OPT_msoft_float))
+      FloatABI = "soft";
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      FloatABI = "hard";
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (FloatABI.empty()) {
+    switch (getToolChain().getTriple().getOS()) {
+    default:
+      // Assume "soft", but warn the user we are guessing.
+      FloatABI = "soft";
+      D.Diag(diag::warn_drv_assuming_mfloat_abi_is) << "soft";
+      break;
+    }
+  }
+
+  if (FloatABI == "soft") {
+    // Floating point operations and argument passing are soft.
+    //
+    // FIXME: This changes CPP defines, we need -target-soft-float.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back("+soft-float");
+  } else {
+    assert(FloatABI == "hard" && "Invalid float abi!");
+    CmdArgs.push_back("-mhard-float");
+  }
+}
+
+void Clang::AddX86TargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  if (!Args.hasFlag(options::OPT_mred_zone,
+                    options::OPT_mno_red_zone,
+                    true) ||
+      Args.hasArg(options::OPT_mkernel) ||
+      Args.hasArg(options::OPT_fapple_kext))
+    CmdArgs.push_back("-disable-red-zone");
+
+  if (Args.hasFlag(options::OPT_msoft_float,
+                   options::OPT_mno_soft_float,
+                   false))
+    CmdArgs.push_back("-no-implicit-float");
+
+  const char *CPUName = 0;
+  if (const Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+    if (StringRef(A->getValue(Args)) == "native") {
+      // FIXME: Reject attempts to use -march=native unless the target matches
+      // the host.
+      //
+      // FIXME: We should also incorporate the detected target features for use
+      // with -native.
+      std::string CPU = llvm::sys::getHostCPUName();
+      if (!CPU.empty())
+        CPUName = Args.MakeArgString(CPU);
+    } else
+      CPUName = A->getValue(Args);
+  }
+
+  // Select the default CPU if none was given (or detection failed).
+  if (!CPUName) {
+    // FIXME: Need target hooks.
+    if (getToolChain().getTriple().isOSDarwin()) {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "core2";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "yonah";
+    } else if (getToolChain().getOS().startswith("haiku"))  {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "x86-64";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "i586";
+    } else if (getToolChain().getOS().startswith("openbsd"))  {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "x86-64";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "i486";
+    } else if (getToolChain().getOS().startswith("freebsd"))  {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "x86-64";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "i486";
+    } else if (getToolChain().getOS().startswith("netbsd"))  {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "x86-64";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "i486";
+    } else {
+      if (getToolChain().getArch() == llvm::Triple::x86_64)
+        CPUName = "x86-64";
+      else if (getToolChain().getArch() == llvm::Triple::x86)
+        CPUName = "pentium4";
+    }
+  }
+
+  if (CPUName) {
+    CmdArgs.push_back("-target-cpu");
+    CmdArgs.push_back(CPUName);
+  }
+
+  // The required algorithm here is slightly strange: the options are applied
+  // in order (so -mno-sse -msse2 disables SSE3), but any option that gets
+  // directly overridden later is ignored (so "-mno-sse -msse2 -mno-sse2 -msse"
+  // is equivalent to "-mno-sse2 -msse"). The -cc1 handling deals with the
+  // former correctly, but not the latter; handle directly-overridden
+  // attributes here.
+  llvm::StringMap<unsigned> PrevFeature;
+  std::vector<const char*> Features;
+  for (arg_iterator it = Args.filtered_begin(options::OPT_m_x86_Features_Group),
+         ie = Args.filtered_end(); it != ie; ++it) {
+    StringRef Name = (*it)->getOption().getName();
+    (*it)->claim();
+
+    // Skip over "-m".
+    assert(Name.startswith("-m") && "Invalid feature name.");
+    Name = Name.substr(2);
+
+    bool IsNegative = Name.startswith("no-");
+    if (IsNegative)
+      Name = Name.substr(3);
+
+    unsigned& Prev = PrevFeature[Name];
+    if (Prev)
+      Features[Prev - 1] = 0;
+    Prev = Features.size() + 1;
+    Features.push_back(Args.MakeArgString((IsNegative ? "-" : "+") + Name));
+  }
+  for (unsigned i = 0; i < Features.size(); i++) {
+    if (Features[i]) {
+      CmdArgs.push_back("-target-feature");
+      CmdArgs.push_back(Features[i]);
+    }
+  }
+}
+
+static Arg* getLastHexagonArchArg (const ArgList &Args)
+{
+  Arg * A = NULL;
+
+  for (ArgList::const_iterator it = Args.begin(), ie = Args.end();
+       it != ie; ++it) {
+    if ((*it)->getOption().matches(options::OPT_march_EQ) ||
+        (*it)->getOption().matches(options::OPT_mcpu_EQ)) {
+      A = *it;
+      A->claim();
+    }
+    else if ((*it)->getOption().matches(options::OPT_m_Joined)){
+      StringRef Value = (*it)->getValue(Args,0);
+      if (Value.startswith("v")) {
+        A = *it;
+        A->claim();
+      }
+    }
+  }
+  return A;
+}
+
+static StringRef getHexagonTargetCPU(const ArgList &Args)
+{
+  Arg *A;
+  llvm::StringRef WhichHexagon;
+
+  // Select the default CPU (v4) if none was given or detection failed.
+  if ((A = getLastHexagonArchArg (Args))) {
+    WhichHexagon = A->getValue(Args);
+    if (WhichHexagon == "")
+      return "v4";
+    else
+      return WhichHexagon;
+  }
+  else
+    return "v4";
+}
+
+void Clang::AddHexagonTargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  llvm::Triple Triple = getToolChain().getTriple();
+
+  CmdArgs.push_back("-target-cpu");
+  CmdArgs.push_back(Args.MakeArgString("hexagon" + getHexagonTargetCPU(Args)));
+  CmdArgs.push_back("-fno-signed-char");
+  CmdArgs.push_back("-nobuiltininc");
+
+  if (Args.hasArg(options::OPT_mqdsp6_compat))  
+    CmdArgs.push_back("-mqdsp6-compat");
+
+  if (Arg *A = Args.getLastArg(options::OPT_G,
+                               options::OPT_msmall_data_threshold_EQ)) {
+    std::string SmallDataThreshold="-small-data-threshold=";
+    SmallDataThreshold += A->getValue(Args);
+    CmdArgs.push_back ("-mllvm");
+    CmdArgs.push_back(Args.MakeArgString(SmallDataThreshold));
+    A->claim();
+  }
+
+  CmdArgs.push_back ("-mllvm");
+  CmdArgs.push_back ("-machine-sink-split=0");
+}
+
+static bool
+shouldUseExceptionTablesForObjCExceptions(unsigned objcABIVersion,
+                                          const llvm::Triple &Triple) {
+  // We use the zero-cost exception tables for Objective-C if the non-fragile
+  // ABI is enabled or when compiling for x86_64 and ARM on Snow Leopard and
+  // later.
+
+  if (objcABIVersion >= 2)
+    return true;
+
+  if (!Triple.isOSDarwin())
+    return false;
+
+  return (!Triple.isMacOSXVersionLT(10,5) &&
+          (Triple.getArch() == llvm::Triple::x86_64 ||
+           Triple.getArch() == llvm::Triple::arm));
+}
+
+/// addExceptionArgs - Adds exception related arguments to the driver command
+/// arguments. There's a master flag, -fexceptions and also language specific
+/// flags to enable/disable C++ and Objective-C exceptions.
+/// This makes it possible to for example disable C++ exceptions but enable
+/// Objective-C exceptions.
+static void addExceptionArgs(const ArgList &Args, types::ID InputType,
+                             const llvm::Triple &Triple,
+                             bool KernelOrKext,
+                             unsigned objcABIVersion,
+                             ArgStringList &CmdArgs) {
+  if (KernelOrKext) {
+    // -mkernel and -fapple-kext imply no exceptions, so claim exception related
+    // arguments now to avoid warnings about unused arguments.
+    Args.ClaimAllArgs(options::OPT_fexceptions);
+    Args.ClaimAllArgs(options::OPT_fno_exceptions);
+    Args.ClaimAllArgs(options::OPT_fobjc_exceptions);
+    Args.ClaimAllArgs(options::OPT_fno_objc_exceptions);
+    Args.ClaimAllArgs(options::OPT_fcxx_exceptions);
+    Args.ClaimAllArgs(options::OPT_fno_cxx_exceptions);
+    return;
+  }
+
+  // Exceptions are enabled by default.
+  bool ExceptionsEnabled = true;
+
+  // This keeps track of whether exceptions were explicitly turned on or off.
+  bool DidHaveExplicitExceptionFlag = false;
+
+  if (Arg *A = Args.getLastArg(options::OPT_fexceptions,
+                               options::OPT_fno_exceptions)) {
+    if (A->getOption().matches(options::OPT_fexceptions))
+      ExceptionsEnabled = true;
+    else
+      ExceptionsEnabled = false;
+
+    DidHaveExplicitExceptionFlag = true;
+  }
+
+  bool ShouldUseExceptionTables = false;
+
+  // Exception tables and cleanups can be enabled with -fexceptions even if the
+  // language itself doesn't support exceptions.
+  if (ExceptionsEnabled && DidHaveExplicitExceptionFlag)
+    ShouldUseExceptionTables = true;
+
+  // Obj-C exceptions are enabled by default, regardless of -fexceptions. This
+  // is not necessarily sensible, but follows GCC.
+  if (types::isObjC(InputType) &&
+      Args.hasFlag(options::OPT_fobjc_exceptions,
+                   options::OPT_fno_objc_exceptions,
+                   true)) {
+    CmdArgs.push_back("-fobjc-exceptions");
+
+    ShouldUseExceptionTables |=
+      shouldUseExceptionTablesForObjCExceptions(objcABIVersion, Triple);
+  }
+
+  if (types::isCXX(InputType)) {
+    bool CXXExceptionsEnabled = ExceptionsEnabled;
+
+    if (Arg *A = Args.getLastArg(options::OPT_fcxx_exceptions,
+                                 options::OPT_fno_cxx_exceptions,
+                                 options::OPT_fexceptions,
+                                 options::OPT_fno_exceptions)) {
+      if (A->getOption().matches(options::OPT_fcxx_exceptions))
+        CXXExceptionsEnabled = true;
+      else if (A->getOption().matches(options::OPT_fno_cxx_exceptions))
+        CXXExceptionsEnabled = false;
+    }
+
+    if (CXXExceptionsEnabled) {
+      CmdArgs.push_back("-fcxx-exceptions");
+
+      ShouldUseExceptionTables = true;
+    }
+  }
+
+  if (ShouldUseExceptionTables)
+    CmdArgs.push_back("-fexceptions");
+}
+
+static bool ShouldDisableCFI(const ArgList &Args,
+                             const ToolChain &TC) {
+  bool Default = true;
+  if (TC.getTriple().isOSDarwin()) {
+    // The native darwin assembler doesn't support cfi directives, so
+    // we disable them if we think the .s file will be passed to it.
+    Default = Args.hasFlag(options::OPT_integrated_as,
+			   options::OPT_no_integrated_as,
+			   TC.IsIntegratedAssemblerDefault());
+  }
+  return !Args.hasFlag(options::OPT_fdwarf2_cfi_asm,
+		       options::OPT_fno_dwarf2_cfi_asm,
+		       Default);
+}
+
+static bool ShouldDisableDwarfDirectory(const ArgList &Args,
+                                        const ToolChain &TC) {
+  bool IsIADefault = TC.IsIntegratedAssemblerDefault();
+  bool UseIntegratedAs = Args.hasFlag(options::OPT_integrated_as,
+                                      options::OPT_no_integrated_as,
+                                      IsIADefault);
+  bool UseDwarfDirectory = Args.hasFlag(options::OPT_fdwarf_directory_asm,
+                                        options::OPT_fno_dwarf_directory_asm,
+                                        UseIntegratedAs);
+  return !UseDwarfDirectory;
+}
+
+/// \brief Check whether the given input tree contains any compilation actions.
+static bool ContainsCompileAction(const Action *A) {
+  if (isa<CompileJobAction>(A))
+    return true;
+
+  for (Action::const_iterator it = A->begin(), ie = A->end(); it != ie; ++it)
+    if (ContainsCompileAction(*it))
+      return true;
+
+  return false;
+}
+
+/// \brief Check if -relax-all should be passed to the internal assembler.
+/// This is done by default when compiling non-assembler source with -O0.
+static bool UseRelaxAll(Compilation &C, const ArgList &Args) {
+  bool RelaxDefault = true;
+
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group))
+    RelaxDefault = A->getOption().matches(options::OPT_O0);
+
+  if (RelaxDefault) {
+    RelaxDefault = false;
+    for (ActionList::const_iterator it = C.getActions().begin(),
+           ie = C.getActions().end(); it != ie; ++it) {
+      if (ContainsCompileAction(*it)) {
+        RelaxDefault = true;
+        break;
+      }
+    }
+  }
+
+  return Args.hasFlag(options::OPT_mrelax_all, options::OPT_mno_relax_all,
+    RelaxDefault);
+}
+
+/// If AddressSanitizer is enabled, add appropriate linker flags (Linux).
+/// This needs to be called before we add the C run-time (malloc, etc).
+static void addAsanRTLinux(const ToolChain &TC, const ArgList &Args,
+                           ArgStringList &CmdArgs) {
+  // Add asan linker flags when linking an executable, but not a shared object.
+  if (Args.hasArg(options::OPT_shared) ||
+      !Args.hasFlag(options::OPT_faddress_sanitizer,
+                    options::OPT_fno_address_sanitizer, false))
+    return;
+
+  // LibAsan is "libclang_rt.asan-<ArchName>.a" in the Linux library resource
+  // directory.
+  SmallString<128> LibAsan(TC.getDriver().ResourceDir);
+  llvm::sys::path::append(LibAsan, "lib", "linux",
+                          (Twine("libclang_rt.asan-") +
+                           TC.getArchName() + ".a"));
+  CmdArgs.push_back(Args.MakeArgString(LibAsan));
+  CmdArgs.push_back("-lpthread");
+  CmdArgs.push_back("-ldl");
+  CmdArgs.push_back("-export-dynamic");
+}
+
+static bool shouldUseFramePointer(const ArgList &Args,
+                                  const llvm::Triple &Triple) {
+  if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
+                               options::OPT_fomit_frame_pointer))
+    return A->getOption().matches(options::OPT_fno_omit_frame_pointer);
+
+  // Don't use a frame pointer on linux x86 and x86_64 if optimizing.
+  if ((Triple.getArch() == llvm::Triple::x86_64 ||
+       Triple.getArch() == llvm::Triple::x86) &&
+      Triple.getOS() == llvm::Triple::Linux) {
+    if (Arg *A = Args.getLastArg(options::OPT_O_Group))
+      if (!A->getOption().matches(options::OPT_O0))
+        return false;
+  }
+
+  return true;
+}
+
+void Clang::ConstructJob(Compilation &C, const JobAction &JA,
+                         const InputInfo &Output,
+                         const InputInfoList &Inputs,
+                         const ArgList &Args,
+                         const char *LinkingOutput) const {
+  bool KernelOrKext = Args.hasArg(options::OPT_mkernel,
+                                  options::OPT_fapple_kext);
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unable to handle multiple inputs.");
+
+  // Invoke ourselves in -cc1 mode.
+  //
+  // FIXME: Implement custom jobs for internal actions.
+  CmdArgs.push_back("-cc1");
+
+  // Add the "effective" target triple.
+  CmdArgs.push_back("-triple");
+  std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
+  CmdArgs.push_back(Args.MakeArgString(TripleStr));
+
+  // Select the appropriate action.
+  bool IsRewriter = false;
+  bool IsModernRewriter = false;
+  
+  if (isa<AnalyzeJobAction>(JA)) {
+    assert(JA.getType() == types::TY_Plist && "Invalid output type.");
+    CmdArgs.push_back("-analyze");
+  } else if (isa<MigrateJobAction>(JA)) {
+    CmdArgs.push_back("-migrate");
+  } else if (isa<PreprocessJobAction>(JA)) {
+    if (Output.getType() == types::TY_Dependencies)
+      CmdArgs.push_back("-Eonly");
+    else
+      CmdArgs.push_back("-E");
+  } else if (isa<AssembleJobAction>(JA)) {
+    CmdArgs.push_back("-emit-obj");
+
+    if (UseRelaxAll(C, Args))
+      CmdArgs.push_back("-mrelax-all");
+
+    // When using an integrated assembler, translate -Wa, and -Xassembler
+    // options.
+    for (arg_iterator it = Args.filtered_begin(options::OPT_Wa_COMMA,
+                                               options::OPT_Xassembler),
+           ie = Args.filtered_end(); it != ie; ++it) {
+      const Arg *A = *it;
+      A->claim();
+
+      for (unsigned i = 0, e = A->getNumValues(); i != e; ++i) {
+        StringRef Value = A->getValue(Args, i);
+
+        if (Value == "-force_cpusubtype_ALL") {
+          // Do nothing, this is the default and we don't support anything else.
+        } else if (Value == "-L") {
+          CmdArgs.push_back("-msave-temp-labels");
+        } else if (Value == "--fatal-warnings") {
+          CmdArgs.push_back("-mllvm");
+          CmdArgs.push_back("-fatal-assembler-warnings");
+        } else if (Value == "--noexecstack") {
+          CmdArgs.push_back("-mnoexecstack");
+        } else {
+          D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+        }
+      }
+    }
+
+    // Also ignore explicit -force_cpusubtype_ALL option.
+    (void) Args.hasArg(options::OPT_force__cpusubtype__ALL);
+  } else if (isa<PrecompileJobAction>(JA)) {
+    // Use PCH if the user requested it.
+    bool UsePCH = D.CCCUsePCH;
+
+    if (UsePCH)
+      CmdArgs.push_back("-emit-pch");
+    else
+      CmdArgs.push_back("-emit-pth");
+  } else {
+    assert(isa<CompileJobAction>(JA) && "Invalid action for clang tool.");
+
+    if (JA.getType() == types::TY_Nothing) {
+      CmdArgs.push_back("-fsyntax-only");
+    } else if (JA.getType() == types::TY_LLVM_IR ||
+               JA.getType() == types::TY_LTO_IR) {
+      CmdArgs.push_back("-emit-llvm");
+    } else if (JA.getType() == types::TY_LLVM_BC ||
+               JA.getType() == types::TY_LTO_BC) {
+      CmdArgs.push_back("-emit-llvm-bc");
+    } else if (JA.getType() == types::TY_PP_Asm) {
+      CmdArgs.push_back("-S");
+    } else if (JA.getType() == types::TY_AST) {
+      CmdArgs.push_back("-emit-pch");
+    } else if (JA.getType() == types::TY_RewrittenObjC) {
+      CmdArgs.push_back("-rewrite-objc");
+      IsModernRewriter = true;
+    } else if (JA.getType() == types::TY_RewrittenLegacyObjC) {
+      CmdArgs.push_back("-rewrite-objc");
+      IsRewriter = true;
+    } else {
+      assert(JA.getType() == types::TY_PP_Asm &&
+             "Unexpected output type!");
+    }
+  }
+
+  // The make clang go fast button.
+  CmdArgs.push_back("-disable-free");
+
+  // Disable the verification pass in -asserts builds.
+#ifdef NDEBUG
+  CmdArgs.push_back("-disable-llvm-verifier");
+#endif
+
+  // Set the main file name, so that debug info works even with
+  // -save-temps.
+  CmdArgs.push_back("-main-file-name");
+  CmdArgs.push_back(darwin::CC1::getBaseInputName(Args, Inputs));
+
+  // Some flags which affect the language (via preprocessor
+  // defines). See darwin::CC1::AddCPPArgs.
+  if (Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-static-define");
+
+  if (isa<AnalyzeJobAction>(JA)) {
+    // Enable region store model by default.
+    CmdArgs.push_back("-analyzer-store=region");
+
+    // Treat blocks as analysis entry points.
+    CmdArgs.push_back("-analyzer-opt-analyze-nested-blocks");
+
+    CmdArgs.push_back("-analyzer-eagerly-assume");
+
+    CmdArgs.push_back("-analyzer-ipa=inlining");
+
+    // Add default argument set.
+    if (!Args.hasArg(options::OPT__analyzer_no_default_checks)) {
+      CmdArgs.push_back("-analyzer-checker=core");
+
+      if (getToolChain().getTriple().getOS() != llvm::Triple::Win32)
+        CmdArgs.push_back("-analyzer-checker=unix");
+
+      if (getToolChain().getTriple().getVendor() == llvm::Triple::Apple)
+        CmdArgs.push_back("-analyzer-checker=osx");
+      
+      CmdArgs.push_back("-analyzer-checker=deadcode");
+      
+      // Enable the following experimental checkers for testing. 
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.UncheckedReturn");
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.getpw");
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.gets");
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.mktemp");      
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.mkstemp");
+      CmdArgs.push_back("-analyzer-checker=security.insecureAPI.vfork");
+    }
+
+    // Set the output format. The default is plist, for (lame) historical
+    // reasons.
+    CmdArgs.push_back("-analyzer-output");
+    if (Arg *A = Args.getLastArg(options::OPT__analyzer_output))
+      CmdArgs.push_back(A->getValue(Args));
+    else
+      CmdArgs.push_back("plist");
+
+    // Disable the presentation of standard compiler warnings when
+    // using --analyze.  We only want to show static analyzer diagnostics
+    // or frontend errors.
+    CmdArgs.push_back("-w");
+
+    // Add -Xanalyzer arguments when running as analyzer.
+    Args.AddAllArgValues(CmdArgs, options::OPT_Xanalyzer);
+  }
+
+  CheckCodeGenerationOptions(D, Args);
+
+  // Perform argument translation for LLVM backend. This
+  // takes some care in reconciling with llvm-gcc. The
+  // issue is that llvm-gcc translates these options based on
+  // the values in cc1, whereas we are processing based on
+  // the driver arguments.
+
+  // This comes from the default translation the driver + cc1
+  // would do to enable flag_pic.
+  //
+  // FIXME: Centralize this code.
+  Arg *LastPICArg = 0;
+  for (ArgList::const_iterator I = Args.begin(), E = Args.end(); I != E; ++I) {
+    if ((*I)->getOption().matches(options::OPT_fPIC) ||
+        (*I)->getOption().matches(options::OPT_fno_PIC) ||
+        (*I)->getOption().matches(options::OPT_fpic) ||
+        (*I)->getOption().matches(options::OPT_fno_pic) ||
+        (*I)->getOption().matches(options::OPT_fPIE) ||
+        (*I)->getOption().matches(options::OPT_fno_PIE) ||
+        (*I)->getOption().matches(options::OPT_fpie) ||
+        (*I)->getOption().matches(options::OPT_fno_pie)) {
+      LastPICArg = *I;
+      (*I)->claim();
+    }
+  }
+  bool PICDisabled = false;
+  bool PICEnabled = false;
+  bool PICForPIE = false;
+  if (LastPICArg) {
+    PICForPIE = (LastPICArg->getOption().matches(options::OPT_fPIE) ||
+                 LastPICArg->getOption().matches(options::OPT_fpie));
+    PICEnabled = (PICForPIE ||
+                  LastPICArg->getOption().matches(options::OPT_fPIC) ||
+                  LastPICArg->getOption().matches(options::OPT_fpic));
+    PICDisabled = !PICEnabled;
+  }
+  // Note that these flags are trump-cards. Regardless of the order w.r.t. the
+  // PIC or PIE options above, if these show up, PIC is disabled.
+  if (Args.hasArg(options::OPT_mkernel))
+    PICDisabled = true;
+  if (Args.hasArg(options::OPT_static))
+    PICDisabled = true;
+  bool DynamicNoPIC = Args.hasArg(options::OPT_mdynamic_no_pic);
+
+  // Select the relocation model.
+  const char *Model = getToolChain().GetForcedPicModel();
+  if (!Model) {
+    if (DynamicNoPIC)
+      Model = "dynamic-no-pic";
+    else if (PICDisabled)
+      Model = "static";
+    else if (PICEnabled)
+      Model = "pic";
+    else
+      Model = getToolChain().GetDefaultRelocationModel();
+  }
+  StringRef ModelStr = Model ? Model : "";
+  if (Model && ModelStr != "pic") {
+    CmdArgs.push_back("-mrelocation-model");
+    CmdArgs.push_back(Model);
+  }
+
+  // Infer the __PIC__ and __PIE__ values.
+  if (ModelStr == "pic" && PICForPIE) {
+    CmdArgs.push_back("-pie-level");
+    CmdArgs.push_back((LastPICArg &&
+                       LastPICArg->getOption().matches(options::OPT_fPIE)) ?
+                      "2" : "1");
+  } else if (ModelStr == "pic" || ModelStr == "dynamic-no-pic") {
+    CmdArgs.push_back("-pic-level");
+    CmdArgs.push_back(((ModelStr != "dynamic-no-pic" && LastPICArg &&
+                        LastPICArg->getOption().matches(options::OPT_fPIC)) ||
+                       getToolChain().getTriple().isOSDarwin()) ? "2" : "1");
+  }
+
+  if (!Args.hasFlag(options::OPT_fmerge_all_constants,
+                    options::OPT_fno_merge_all_constants))
+    CmdArgs.push_back("-fno-merge-all-constants");
+
+  // LLVM Code Generator Options.
+
+  if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
+    CmdArgs.push_back("-mregparm");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Args.hasFlag(options::OPT_mrtd, options::OPT_mno_rtd, false))
+    CmdArgs.push_back("-mrtd");
+
+  if (shouldUseFramePointer(Args, getToolChain().getTriple()))
+    CmdArgs.push_back("-mdisable-fp-elim");
+  if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
+                    options::OPT_fno_zero_initialized_in_bss))
+    CmdArgs.push_back("-mno-zero-initialized-in-bss");
+  if (!Args.hasFlag(options::OPT_fstrict_aliasing,
+                    options::OPT_fno_strict_aliasing,
+                    getToolChain().IsStrictAliasingDefault()))
+    CmdArgs.push_back("-relaxed-aliasing");
+  if (Args.hasFlag(options::OPT_fstrict_enums, options::OPT_fno_strict_enums,
+                   false))
+    CmdArgs.push_back("-fstrict-enums");
+  if (!Args.hasFlag(options::OPT_foptimize_sibling_calls,
+                    options::OPT_fno_optimize_sibling_calls))
+    CmdArgs.push_back("-mdisable-tail-calls");
+
+  // Handle various floating point optimization flags, mapping them to the
+  // appropriate LLVM code generation flags. The pattern for all of these is to
+  // default off the codegen optimizations, and if any flag enables them and no
+  // flag disables them after the flag enabling them, enable the codegen
+  // optimization. This is complicated by several "umbrella" flags.
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_ffinite_math_only,
+                               options::OPT_fno_finite_math_only,
+                               options::OPT_fhonor_infinities,
+                               options::OPT_fno_honor_infinities))
+    if (A->getOption().getID() != options::OPT_fno_finite_math_only &&
+        A->getOption().getID() != options::OPT_fhonor_infinities)
+      CmdArgs.push_back("-menable-no-infs");
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_ffinite_math_only,
+                               options::OPT_fno_finite_math_only,
+                               options::OPT_fhonor_nans,
+                               options::OPT_fno_honor_nans))
+    if (A->getOption().getID() != options::OPT_fno_finite_math_only &&
+        A->getOption().getID() != options::OPT_fhonor_nans)
+      CmdArgs.push_back("-menable-no-nans");
+
+  // -fno-math-errno is default.
+  bool MathErrno = false;
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_fmath_errno,
+                               options::OPT_fno_math_errno)) {
+    if (A->getOption().getID() == options::OPT_fmath_errno) {
+      CmdArgs.push_back("-fmath-errno");
+      MathErrno = true;
+    }
+  }
+
+  // There are several flags which require disabling very specific
+  // optimizations. Any of these being disabled forces us to turn off the
+  // entire set of LLVM optimizations, so collect them through all the flag
+  // madness.
+  bool AssociativeMath = false;
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_funsafe_math_optimizations,
+                               options::OPT_fno_unsafe_math_optimizations,
+                               options::OPT_fassociative_math,
+                               options::OPT_fno_associative_math))
+    if (A->getOption().getID() != options::OPT_fno_unsafe_math_optimizations &&
+        A->getOption().getID() != options::OPT_fno_associative_math)
+      AssociativeMath = true;
+  bool ReciprocalMath = false;
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_funsafe_math_optimizations,
+                               options::OPT_fno_unsafe_math_optimizations,
+                               options::OPT_freciprocal_math,
+                               options::OPT_fno_reciprocal_math))
+    if (A->getOption().getID() != options::OPT_fno_unsafe_math_optimizations &&
+        A->getOption().getID() != options::OPT_fno_reciprocal_math)
+      ReciprocalMath = true;
+  bool SignedZeros = true;
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_funsafe_math_optimizations,
+                               options::OPT_fno_unsafe_math_optimizations,
+                               options::OPT_fsigned_zeros,
+                               options::OPT_fno_signed_zeros))
+    if (A->getOption().getID() != options::OPT_fno_unsafe_math_optimizations &&
+        A->getOption().getID() != options::OPT_fsigned_zeros)
+      SignedZeros = false;
+  bool TrappingMath = true;
+  if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+                               options::OPT_funsafe_math_optimizations,
+                               options::OPT_fno_unsafe_math_optimizations,
+                               options::OPT_ftrapping_math,
+                               options::OPT_fno_trapping_math))
+    if (A->getOption().getID() != options::OPT_fno_unsafe_math_optimizations &&
+        A->getOption().getID() != options::OPT_ftrapping_math)
+      TrappingMath = false;
+  if (!MathErrno && AssociativeMath && ReciprocalMath && !SignedZeros &&
+      !TrappingMath)
+    CmdArgs.push_back("-menable-unsafe-fp-math");
+
+  // We separately look for the '-ffast-math' flag, and if we find it, tell the
+  // frontend to provide the appropriate preprocessor macros. This is distinct
+  // from enabling any optimizations as it induces a language change which must
+  // survive serialization and deserialization, etc.
+  if (Args.hasArg(options::OPT_ffast_math))
+    CmdArgs.push_back("-ffast-math");
+
+  // Decide whether to use verbose asm. Verbose assembly is the default on
+  // toolchains which have the integrated assembler on by default.
+  bool IsVerboseAsmDefault = getToolChain().IsIntegratedAssemblerDefault();
+  if (Args.hasFlag(options::OPT_fverbose_asm, options::OPT_fno_verbose_asm,
+                   IsVerboseAsmDefault) ||
+      Args.hasArg(options::OPT_dA))
+    CmdArgs.push_back("-masm-verbose");
+
+  if (Args.hasArg(options::OPT_fdebug_pass_structure)) {
+    CmdArgs.push_back("-mdebug-pass");
+    CmdArgs.push_back("Structure");
+  }
+  if (Args.hasArg(options::OPT_fdebug_pass_arguments)) {
+    CmdArgs.push_back("-mdebug-pass");
+    CmdArgs.push_back("Arguments");
+  }
+
+  // Enable -mconstructor-aliases except on darwin, where we have to
+  // work around a linker bug;  see <rdar://problem/7651567>.
+  if (!getToolChain().getTriple().isOSDarwin())
+    CmdArgs.push_back("-mconstructor-aliases");
+
+  // Darwin's kernel doesn't support guard variables; just die if we
+  // try to use them.
+  if (KernelOrKext && getToolChain().getTriple().isOSDarwin())
+    CmdArgs.push_back("-fforbid-guard-variables");
+
+  if (Args.hasArg(options::OPT_mms_bitfields)) {
+    CmdArgs.push_back("-mms-bitfields");
+  }
+
+  // This is a coarse approximation of what llvm-gcc actually does, both
+  // -fasynchronous-unwind-tables and -fnon-call-exceptions interact in more
+  // complicated ways.
+  bool AsynchronousUnwindTables =
+    Args.hasFlag(options::OPT_fasynchronous_unwind_tables,
+                 options::OPT_fno_asynchronous_unwind_tables,
+                 getToolChain().IsUnwindTablesDefault() &&
+                 !KernelOrKext);
+  if (Args.hasFlag(options::OPT_funwind_tables, options::OPT_fno_unwind_tables,
+                   AsynchronousUnwindTables))
+    CmdArgs.push_back("-munwind-tables");
+
+  if (Arg *A = Args.getLastArg(options::OPT_flimited_precision_EQ)) {
+    CmdArgs.push_back("-mlimit-float-precision");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  // FIXME: Handle -mtune=.
+  (void) Args.hasArg(options::OPT_mtune_EQ);
+
+  if (Arg *A = Args.getLastArg(options::OPT_mcmodel_EQ)) {
+    CmdArgs.push_back("-mcode-model");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  // Add target specific cpu and features flags.
+  switch(getToolChain().getTriple().getArch()) {
+  default:
+    break;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    AddARMTargetArgs(Args, CmdArgs, KernelOrKext);
+    break;
+
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el:
+    AddMIPSTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::sparc:
+    AddSparcTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+    AddX86TargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::hexagon:
+    AddHexagonTargetArgs(Args, CmdArgs);
+    break;
+  }
+
+
+
+  // Pass the linker version in use.
+  if (Arg *A = Args.getLastArg(options::OPT_mlinker_version_EQ)) {
+    CmdArgs.push_back("-target-linker-version");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  // -mno-omit-leaf-frame-pointer is the default on Darwin.
+  if (Args.hasFlag(options::OPT_momit_leaf_frame_pointer,
+                   options::OPT_mno_omit_leaf_frame_pointer,
+                   !getToolChain().getTriple().isOSDarwin()))
+    CmdArgs.push_back("-momit-leaf-frame-pointer");
+
+  // Explicitly error on some things we know we don't support and can't just
+  // ignore.
+  types::ID InputType = Inputs[0].getType();
+  if (!Args.hasArg(options::OPT_fallow_unsupported)) {
+    Arg *Unsupported;
+    if (types::isCXX(InputType) &&
+        getToolChain().getTriple().isOSDarwin() &&
+        getToolChain().getTriple().getArch() == llvm::Triple::x86) {
+      if ((Unsupported = Args.getLastArg(options::OPT_fapple_kext)) ||
+          (Unsupported = Args.getLastArg(options::OPT_mkernel)))
+        D.Diag(diag::err_drv_clang_unsupported_opt_cxx_darwin_i386)
+          << Unsupported->getOption().getName();
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_v);
+  Args.AddLastArg(CmdArgs, options::OPT_H);
+  if (D.CCPrintHeaders && !D.CCGenDiagnostics) {
+    CmdArgs.push_back("-header-include-file");
+    CmdArgs.push_back(D.CCPrintHeadersFilename ?
+                      D.CCPrintHeadersFilename : "-");
+  }
+  Args.AddLastArg(CmdArgs, options::OPT_P);
+  Args.AddLastArg(CmdArgs, options::OPT_print_ivar_layout);
+
+  if (D.CCLogDiagnostics && !D.CCGenDiagnostics) {
+    CmdArgs.push_back("-diagnostic-log-file");
+    CmdArgs.push_back(D.CCLogDiagnosticsFilename ?
+                      D.CCLogDiagnosticsFilename : "-");
+  }
+
+  // Special case debug options to only pass -g to clang. This is
+  // wrong.
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  if (Arg *A = Args.getLastArg(options::OPT_g_Group))
+    if (!A->getOption().matches(options::OPT_g0)) {
+      CmdArgs.push_back("-g");
+    }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_ffunction_sections);
+  Args.AddAllArgs(CmdArgs, options::OPT_fdata_sections);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_finstrument_functions);
+
+  if (Args.hasArg(options::OPT_ftest_coverage) ||
+      Args.hasArg(options::OPT_coverage))
+    CmdArgs.push_back("-femit-coverage-notes");
+  if (Args.hasArg(options::OPT_fprofile_arcs) ||
+      Args.hasArg(options::OPT_coverage))
+    CmdArgs.push_back("-femit-coverage-data");
+
+  if (C.getArgs().hasArg(options::OPT_c) ||
+      C.getArgs().hasArg(options::OPT_S)) {
+    if (Output.isFilename()) {
+      CmdArgs.push_back("-coverage-file");
+      CmdArgs.push_back(Args.MakeArgString(Output.getFilename()));
+    }
+  }
+
+  // Pass options for controlling the default header search paths.
+  if (Args.hasArg(options::OPT_nostdinc)) {
+    CmdArgs.push_back("-nostdsysteminc");
+    CmdArgs.push_back("-nobuiltininc");
+  } else {
+    if (Args.hasArg(options::OPT_nostdlibinc))
+        CmdArgs.push_back("-nostdsysteminc");
+    Args.AddLastArg(CmdArgs, options::OPT_nostdincxx);
+    Args.AddLastArg(CmdArgs, options::OPT_nobuiltininc);
+  }
+
+  // Pass the path to compiler resource files.
+  CmdArgs.push_back("-resource-dir");
+  CmdArgs.push_back(D.ResourceDir.c_str());
+
+  Args.AddLastArg(CmdArgs, options::OPT_working_directory);
+
+  bool ARCMTEnabled = false;
+  if (!Args.hasArg(options::OPT_fno_objc_arc)) {
+    if (const Arg *A = Args.getLastArg(options::OPT_ccc_arcmt_check,
+                                       options::OPT_ccc_arcmt_modify,
+                                       options::OPT_ccc_arcmt_migrate)) {
+      ARCMTEnabled = true;
+      switch (A->getOption().getID()) {
+      default:
+        llvm_unreachable("missed a case");
+      case options::OPT_ccc_arcmt_check:
+        CmdArgs.push_back("-arcmt-check");
+        break;
+      case options::OPT_ccc_arcmt_modify:
+        CmdArgs.push_back("-arcmt-modify");
+        break;
+      case options::OPT_ccc_arcmt_migrate:
+        CmdArgs.push_back("-arcmt-migrate");
+        CmdArgs.push_back("-mt-migrate-directory");
+        CmdArgs.push_back(A->getValue(Args));
+
+        Args.AddLastArg(CmdArgs, options::OPT_arcmt_migrate_report_output);
+        Args.AddLastArg(CmdArgs, options::OPT_arcmt_migrate_emit_arc_errors);
+        break;
+      }
+    }
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_ccc_objcmt_migrate)) {
+    if (ARCMTEnabled) {
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+        << A->getAsString(Args) << "-ccc-arcmt-migrate";
+    }
+    CmdArgs.push_back("-mt-migrate-directory");
+    CmdArgs.push_back(A->getValue(Args));
+
+    if (!Args.hasArg(options::OPT_objcmt_migrate_literals,
+                     options::OPT_objcmt_migrate_subscripting)) {
+      // None specified, means enable them all.
+      CmdArgs.push_back("-objcmt-migrate-literals");
+      CmdArgs.push_back("-objcmt-migrate-subscripting");
+    } else {
+      Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_literals);
+      Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_subscripting);
+    }
+  }
+
+  // Add preprocessing options like -I, -D, etc. if we are using the
+  // preprocessor.
+  //
+  // FIXME: Support -fpreprocessed
+  if (types::getPreprocessedType(InputType) != types::TY_INVALID)
+    AddPreprocessingOptions(C, D, Args, CmdArgs, Output, Inputs);
+
+  // Don't warn about "clang -c -DPIC -fPIC test.i" because libtool.m4 assumes
+  // that "The compiler can only warn and ignore the option if not recognized".
+  // When building with ccache, it will pass -D options to clang even on
+  // preprocessed inputs and configure concludes that -fPIC is not supported.
+  Args.ClaimAllArgs(options::OPT_D);
+
+  // Manually translate -O to -O2 and -O4 to -O3; let clang reject
+  // others.
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+    if (A->getOption().matches(options::OPT_O4))
+      CmdArgs.push_back("-O3");
+    else if (A->getOption().matches(options::OPT_O) &&
+             A->getValue(Args)[0] == '\0')
+      CmdArgs.push_back("-O2");
+    else
+      A->render(Args, CmdArgs);
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_W_Group);
+  Args.AddLastArg(CmdArgs, options::OPT_pedantic);
+  Args.AddLastArg(CmdArgs, options::OPT_pedantic_errors);
+  Args.AddLastArg(CmdArgs, options::OPT_w);
+
+  // Handle -{std, ansi, trigraphs} -- take the last of -{std, ansi}
+  // (-ansi is equivalent to -std=c89).
+  //
+  // If a std is supplied, only add -trigraphs if it follows the
+  // option.
+  if (Arg *Std = Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi)) {
+    if (Std->getOption().matches(options::OPT_ansi))
+      if (types::isCXX(InputType))
+        CmdArgs.push_back("-std=c++98");
+      else
+        CmdArgs.push_back("-std=c89");
+    else
+      Std->render(Args, CmdArgs);
+
+    if (Arg *A = Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi,
+                                 options::OPT_trigraphs))
+      if (A != Std)
+        A->render(Args, CmdArgs);
+  } else {
+    // Honor -std-default.
+    //
+    // FIXME: Clang doesn't correctly handle -std= when the input language
+    // doesn't match. For the time being just ignore this for C++ inputs;
+    // eventually we want to do all the standard defaulting here instead of
+    // splitting it between the driver and clang -cc1.
+    if (!types::isCXX(InputType))
+        Args.AddAllArgsTranslated(CmdArgs, options::OPT_std_default_EQ,
+                                  "-std=", /*Joined=*/true);
+    Args.AddLastArg(CmdArgs, options::OPT_trigraphs);
+  }
+
+  // Map the bizarre '-Wwrite-strings' flag to a more sensible
+  // '-fconst-strings'; this better indicates its actual behavior.
+  if (Args.hasFlag(options::OPT_Wwrite_strings, options::OPT_Wno_write_strings,
+                   false)) {
+    // For perfect compatibility with GCC, we do this even in the presence of
+    // '-w'. This flag names something other than a warning for GCC.
+    CmdArgs.push_back("-fconst-strings");
+  }
+
+  // GCC provides a macro definition '__DEPRECATED' when -Wdeprecated is active
+  // during C++ compilation, which it is by default. GCC keeps this define even
+  // in the presence of '-w', match this behavior bug-for-bug.
+  if (types::isCXX(InputType) &&
+      Args.hasFlag(options::OPT_Wdeprecated, options::OPT_Wno_deprecated,
+                   true)) {
+    CmdArgs.push_back("-fdeprecated-macro");
+  }
+
+  // Translate GCC's misnamer '-fasm' arguments to '-fgnu-keywords'.
+  if (Arg *Asm = Args.getLastArg(options::OPT_fasm, options::OPT_fno_asm)) {
+    if (Asm->getOption().matches(options::OPT_fasm))
+      CmdArgs.push_back("-fgnu-keywords");
+    else
+      CmdArgs.push_back("-fno-gnu-keywords");
+  }
+
+  if (ShouldDisableCFI(Args, getToolChain()))
+    CmdArgs.push_back("-fno-dwarf2-cfi-asm");
+
+  if (ShouldDisableDwarfDirectory(Args, getToolChain()))
+    CmdArgs.push_back("-fno-dwarf-directory-asm");
+
+  if (const char *pwd = ::getenv("PWD")) {
+    // GCC also verifies that stat(pwd) and stat(".") have the same inode
+    // number. Not doing those because stats are slow, but we could.
+    if (llvm::sys::path::is_absolute(pwd)) {
+      std::string CompDir = pwd;
+      CmdArgs.push_back("-fdebug-compilation-dir");
+      CmdArgs.push_back(Args.MakeArgString(CompDir));
+    }
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftemplate_depth_,
+                               options::OPT_ftemplate_depth_EQ)) {
+    CmdArgs.push_back("-ftemplate-depth");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstexpr_depth_EQ)) {
+    CmdArgs.push_back("-fconstexpr-depth");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_Wlarge_by_value_copy_EQ,
+                               options::OPT_Wlarge_by_value_copy_def)) {
+    CmdArgs.push_back("-Wlarge-by-value-copy");
+    if (A->getNumValues())
+      CmdArgs.push_back(A->getValue(Args));
+    else
+      CmdArgs.push_back("64"); // default value for -Wlarge-by-value-copy.
+  }
+
+  if (Args.hasArg(options::OPT__relocatable_pch))
+    CmdArgs.push_back("-relocatable-pch");
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstant_string_class_EQ)) {
+    CmdArgs.push_back("-fconstant-string-class");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftabstop_EQ)) {
+    CmdArgs.push_back("-ftabstop");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  CmdArgs.push_back("-ferror-limit");
+  if (Arg *A = Args.getLastArg(options::OPT_ferror_limit_EQ))
+    CmdArgs.push_back(A->getValue(Args));
+  else
+    CmdArgs.push_back("19");
+
+  if (Arg *A = Args.getLastArg(options::OPT_fmacro_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-fmacro-backtrace-limit");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftemplate_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-ftemplate-backtrace-limit");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstexpr_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-fconstexpr-backtrace-limit");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  // Pass -fmessage-length=.
+  CmdArgs.push_back("-fmessage-length");
+  if (Arg *A = Args.getLastArg(options::OPT_fmessage_length_EQ)) {
+    CmdArgs.push_back(A->getValue(Args));
+  } else {
+    // If -fmessage-length=N was not specified, determine whether this is a
+    // terminal and, if so, implicitly define -fmessage-length appropriately.
+    unsigned N = llvm::sys::Process::StandardErrColumns();
+    CmdArgs.push_back(Args.MakeArgString(Twine(N)));
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_fvisibility_EQ)) {
+    CmdArgs.push_back("-fvisibility");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_fvisibility_inlines_hidden);
+
+  // -fhosted is default.
+  if (Args.hasFlag(options::OPT_ffreestanding, options::OPT_fhosted, false) ||
+      KernelOrKext)
+    CmdArgs.push_back("-ffreestanding");
+
+  // Forward -f (flag) options which we can pass directly.
+  Args.AddLastArg(CmdArgs, options::OPT_fcatch_undefined_behavior);
+  Args.AddLastArg(CmdArgs, options::OPT_femit_all_decls);
+  Args.AddLastArg(CmdArgs, options::OPT_fheinous_gnu_extensions);
+  Args.AddLastArg(CmdArgs, options::OPT_flimit_debug_info);
+  Args.AddLastArg(CmdArgs, options::OPT_fno_limit_debug_info);
+  Args.AddLastArg(CmdArgs, options::OPT_fno_operator_names);
+  Args.AddLastArg(CmdArgs, options::OPT_faltivec);
+
+  // Report and error for -faltivec on anything other then PowerPC.
+  if (const Arg *A = Args.getLastArg(options::OPT_faltivec))
+    if (!(getToolChain().getTriple().getArch() == llvm::Triple::ppc ||
+          getToolChain().getTriple().getArch() == llvm::Triple::ppc64))
+      D.Diag(diag::err_drv_argument_only_allowed_with)
+        << A->getAsString(Args) << "ppc/ppc64";
+
+  if (getToolChain().SupportsProfiling())
+    Args.AddLastArg(CmdArgs, options::OPT_pg);
+
+  if (Args.hasFlag(options::OPT_faddress_sanitizer,
+                   options::OPT_fno_address_sanitizer, false))
+    CmdArgs.push_back("-faddress-sanitizer");
+
+  if (Args.hasFlag(options::OPT_fthread_sanitizer,
+                   options::OPT_fno_thread_sanitizer, false))
+    CmdArgs.push_back("-fthread-sanitizer");
+
+  // -flax-vector-conversions is default.
+  if (!Args.hasFlag(options::OPT_flax_vector_conversions,
+                    options::OPT_fno_lax_vector_conversions))
+    CmdArgs.push_back("-fno-lax-vector-conversions");
+
+  if (Args.getLastArg(options::OPT_fapple_kext))
+    CmdArgs.push_back("-fapple-kext");
+
+  Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
+  Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_print_source_range_info);
+  Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_parseable_fixits);
+  Args.AddLastArg(CmdArgs, options::OPT_ftime_report);
+  Args.AddLastArg(CmdArgs, options::OPT_ftrapv);
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftrapv_handler_EQ)) {
+    CmdArgs.push_back("-ftrapv-handler");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_ftrap_function_EQ);
+
+  // -fno-strict-overflow implies -fwrapv if it isn't disabled, but
+  // -fstrict-overflow won't turn off an explicitly enabled -fwrapv.
+  if (Arg *A = Args.getLastArg(options::OPT_fwrapv,
+                               options::OPT_fno_wrapv)) {
+    if (A->getOption().matches(options::OPT_fwrapv))
+      CmdArgs.push_back("-fwrapv");
+  } else if (Arg *A = Args.getLastArg(options::OPT_fstrict_overflow,
+                                      options::OPT_fno_strict_overflow)) {
+    if (A->getOption().matches(options::OPT_fno_strict_overflow))
+      CmdArgs.push_back("-fwrapv");
+  }
+  Args.AddLastArg(CmdArgs, options::OPT_fwritable_strings);
+  Args.AddLastArg(CmdArgs, options::OPT_funroll_loops);
+
+  Args.AddLastArg(CmdArgs, options::OPT_pthread);
+
+  // -stack-protector=0 is default.
+  unsigned StackProtectorLevel = 0;
+  if (Arg *A = Args.getLastArg(options::OPT_fno_stack_protector,
+                               options::OPT_fstack_protector_all,
+                               options::OPT_fstack_protector)) {
+    if (A->getOption().matches(options::OPT_fstack_protector))
+      StackProtectorLevel = 1;
+    else if (A->getOption().matches(options::OPT_fstack_protector_all))
+      StackProtectorLevel = 2;
+  } else {
+    StackProtectorLevel =
+      getToolChain().GetDefaultStackProtectorLevel(KernelOrKext);
+  }
+  if (StackProtectorLevel) {
+    CmdArgs.push_back("-stack-protector");
+    CmdArgs.push_back(Args.MakeArgString(Twine(StackProtectorLevel)));
+  }
+
+  // Translate -mstackrealign
+  if (Args.hasFlag(options::OPT_mstackrealign, options::OPT_mno_stackrealign,
+                   false)) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-force-align-stack");
+  }
+  if (!Args.hasFlag(options::OPT_mno_stackrealign, options::OPT_mstackrealign,
+                   false)) {
+    CmdArgs.push_back(Args.MakeArgString("-mstackrealign"));
+  }
+
+  if (Args.hasArg(options::OPT_mstack_alignment)) {
+    StringRef alignment = Args.getLastArgValue(options::OPT_mstack_alignment);
+    CmdArgs.push_back(Args.MakeArgString("-mstack-alignment=" + alignment));
+  }
+
+  // Forward -f options with positive and negative forms; we translate
+  // these by hand.
+
+  if (Args.hasArg(options::OPT_mkernel)) {
+    if (!Args.hasArg(options::OPT_fapple_kext) && types::isCXX(InputType))
+      CmdArgs.push_back("-fapple-kext");
+    if (!Args.hasArg(options::OPT_fbuiltin))
+      CmdArgs.push_back("-fno-builtin");
+    Args.ClaimAllArgs(options::OPT_fno_builtin);
+  }
+  // -fbuiltin is default.
+  else if (!Args.hasFlag(options::OPT_fbuiltin, options::OPT_fno_builtin))
+    CmdArgs.push_back("-fno-builtin");
+
+  if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
+                    options::OPT_fno_assume_sane_operator_new))
+    CmdArgs.push_back("-fno-assume-sane-operator-new");
+
+  // -fblocks=0 is default.
+  if (Args.hasFlag(options::OPT_fblocks, options::OPT_fno_blocks,
+                   getToolChain().IsBlocksDefault()) ||
+        (Args.hasArg(options::OPT_fgnu_runtime) &&
+         Args.hasArg(options::OPT_fobjc_nonfragile_abi) &&
+         !Args.hasArg(options::OPT_fno_blocks))) {
+    CmdArgs.push_back("-fblocks");
+
+    if (!Args.hasArg(options::OPT_fgnu_runtime) && 
+        !getToolChain().hasBlocksRuntime())
+      CmdArgs.push_back("-fblocks-runtime-optional");
+  }
+
+  // -fmodules enables modules (off by default). However, for C++/Objective-C++,
+  // users must also pass -fcxx-modules. The latter flag will disappear once the
+  // modules implementation is solid for C++/Objective-C++ programs as well.
+  if (Args.hasFlag(options::OPT_fmodules, options::OPT_fno_modules, false)) {
+    bool AllowedInCXX = Args.hasFlag(options::OPT_fcxx_modules, 
+                                     options::OPT_fno_cxx_modules, 
+                                     false);
+    if (AllowedInCXX || !types::isCXX(InputType))
+      CmdArgs.push_back("-fmodules");
+  }
+
+  // -faccess-control is default.
+  if (Args.hasFlag(options::OPT_fno_access_control,
+                   options::OPT_faccess_control,
+                   false))
+    CmdArgs.push_back("-fno-access-control");
+
+  // -felide-constructors is the default.
+  if (Args.hasFlag(options::OPT_fno_elide_constructors,
+                   options::OPT_felide_constructors,
+                   false))
+    CmdArgs.push_back("-fno-elide-constructors");
+
+  // -frtti is default.
+  if (!Args.hasFlag(options::OPT_frtti, options::OPT_fno_rtti) ||
+      KernelOrKext)
+    CmdArgs.push_back("-fno-rtti");
+
+  // -fshort-enums=0 is default for all architectures except Hexagon.
+  if (Args.hasFlag(options::OPT_fshort_enums,
+                   options::OPT_fno_short_enums,
+                   getToolChain().getTriple().getArch() ==
+                   llvm::Triple::hexagon))
+    CmdArgs.push_back("-fshort-enums");
+
+  // -fsigned-char is default.
+  if (!Args.hasFlag(options::OPT_fsigned_char, options::OPT_funsigned_char,
+                    isSignedCharDefault(getToolChain().getTriple())))
+    CmdArgs.push_back("-fno-signed-char");
+
+  // -fthreadsafe-static is default.
+  if (!Args.hasFlag(options::OPT_fthreadsafe_statics,
+                    options::OPT_fno_threadsafe_statics))
+    CmdArgs.push_back("-fno-threadsafe-statics");
+
+  // -fuse-cxa-atexit is default.
+  if (!Args.hasFlag(options::OPT_fuse_cxa_atexit,
+                    options::OPT_fno_use_cxa_atexit,
+                   getToolChain().getTriple().getOS() != llvm::Triple::Cygwin &&
+                  getToolChain().getTriple().getOS() != llvm::Triple::MinGW32 &&
+              getToolChain().getTriple().getArch() != llvm::Triple::hexagon) ||
+      KernelOrKext)
+    CmdArgs.push_back("-fno-use-cxa-atexit");
+
+  // -fms-extensions=0 is default.
+  if (Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
+                   getToolChain().getTriple().getOS() == llvm::Triple::Win32))
+    CmdArgs.push_back("-fms-extensions");
+
+  // -fms-compatibility=0 is default.
+  if (Args.hasFlag(options::OPT_fms_compatibility, 
+                   options::OPT_fno_ms_compatibility,
+                   (getToolChain().getTriple().getOS() == llvm::Triple::Win32 &&
+                    Args.hasFlag(options::OPT_fms_extensions, 
+                                 options::OPT_fno_ms_extensions,
+                                 true))))
+    CmdArgs.push_back("-fms-compatibility");
+
+  // -fmsc-version=1300 is default.
+  if (Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
+                   getToolChain().getTriple().getOS() == llvm::Triple::Win32) ||
+      Args.hasArg(options::OPT_fmsc_version)) {
+    StringRef msc_ver = Args.getLastArgValue(options::OPT_fmsc_version);
+    if (msc_ver.empty())
+      CmdArgs.push_back("-fmsc-version=1300");
+    else
+      CmdArgs.push_back(Args.MakeArgString("-fmsc-version=" + msc_ver));
+  }
+
+
+  // -fborland-extensions=0 is default.
+  if (Args.hasFlag(options::OPT_fborland_extensions,
+                   options::OPT_fno_borland_extensions, false))
+    CmdArgs.push_back("-fborland-extensions");
+
+  // -fno-delayed-template-parsing is default, except for Windows where MSVC STL
+  // needs it.
+  if (Args.hasFlag(options::OPT_fdelayed_template_parsing,
+                   options::OPT_fno_delayed_template_parsing,
+                   getToolChain().getTriple().getOS() == llvm::Triple::Win32))
+    CmdArgs.push_back("-fdelayed-template-parsing");
+
+  // -fgnu-keywords default varies depending on language; only pass if
+  // specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fgnu_keywords,
+                               options::OPT_fno_gnu_keywords))
+    A->render(Args, CmdArgs);
+
+  if (Args.hasFlag(options::OPT_fgnu89_inline,
+                   options::OPT_fno_gnu89_inline,
+                   false))
+    CmdArgs.push_back("-fgnu89-inline");
+
+  if (Args.hasArg(options::OPT_fno_inline))
+    CmdArgs.push_back("-fno-inline");
+
+  if (Args.hasArg(options::OPT_fno_inline_functions))
+    CmdArgs.push_back("-fno-inline-functions");
+
+  // -fobjc-nonfragile-abi=0 is default.
+  ObjCRuntime objCRuntime;
+  unsigned objcABIVersion = 0;
+  bool NeXTRuntimeIsDefault
+    = (IsRewriter || IsModernRewriter ||
+       getToolChain().getTriple().isOSDarwin());
+  if (Args.hasFlag(options::OPT_fnext_runtime, options::OPT_fgnu_runtime,
+                   NeXTRuntimeIsDefault)) {
+    objCRuntime.setKind(ObjCRuntime::NeXT);
+  } else {
+    CmdArgs.push_back("-fgnu-runtime");
+    objCRuntime.setKind(ObjCRuntime::GNU);
+  }
+  getToolChain().configureObjCRuntime(objCRuntime);
+  if (objCRuntime.HasARC)
+    CmdArgs.push_back("-fobjc-runtime-has-arc");
+  if (objCRuntime.HasWeak)
+    CmdArgs.push_back("-fobjc-runtime-has-weak");
+  if (objCRuntime.HasTerminate)
+    CmdArgs.push_back("-fobjc-runtime-has-terminate");
+
+  // Compute the Objective-C ABI "version" to use. Version numbers are
+  // slightly confusing for historical reasons:
+  //   1 - Traditional "fragile" ABI
+  //   2 - Non-fragile ABI, version 1
+  //   3 - Non-fragile ABI, version 2
+  objcABIVersion = 1;
+  // If -fobjc-abi-version= is present, use that to set the version.
+  if (Arg *A = Args.getLastArg(options::OPT_fobjc_abi_version_EQ)) {
+    if (StringRef(A->getValue(Args)) == "1")
+      objcABIVersion = 1;
+    else if (StringRef(A->getValue(Args)) == "2")
+      objcABIVersion = 2;
+    else if (StringRef(A->getValue(Args)) == "3")
+      objcABIVersion = 3;
+    else
+      D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+  } else {
+    // Otherwise, determine if we are using the non-fragile ABI.
+    bool NonFragileABIIsDefault = 
+      (IsModernRewriter || 
+       (!IsRewriter && getToolChain().IsObjCNonFragileABIDefault()));
+    if (Args.hasFlag(options::OPT_fobjc_nonfragile_abi,
+                     options::OPT_fno_objc_nonfragile_abi,
+                     NonFragileABIIsDefault)) {
+      // Determine the non-fragile ABI version to use.
+#ifdef DISABLE_DEFAULT_NONFRAGILEABI_TWO
+      unsigned NonFragileABIVersion = 1;
+#else
+      unsigned NonFragileABIVersion = 2;
+#endif
+
+      if (Arg *A = Args.getLastArg(
+            options::OPT_fobjc_nonfragile_abi_version_EQ)) {
+        if (StringRef(A->getValue(Args)) == "1")
+          NonFragileABIVersion = 1;
+        else if (StringRef(A->getValue(Args)) == "2")
+          NonFragileABIVersion = 2;
+        else
+          D.Diag(diag::err_drv_clang_unsupported)
+            << A->getAsString(Args);
+      }
+
+      objcABIVersion = 1 + NonFragileABIVersion;
+    } else {
+      objcABIVersion = 1;
+    }
+  }
+
+  if (objcABIVersion == 1) {
+    CmdArgs.push_back("-fobjc-fragile-abi");
+  } else {
+    // -fobjc-dispatch-method is only relevant with the nonfragile-abi, and
+    // legacy is the default.
+    if (!Args.hasFlag(options::OPT_fobjc_legacy_dispatch,
+                      options::OPT_fno_objc_legacy_dispatch,
+                      getToolChain().IsObjCLegacyDispatchDefault())) {
+      if (getToolChain().UseObjCMixedDispatch())
+        CmdArgs.push_back("-fobjc-dispatch-method=mixed");
+      else
+        CmdArgs.push_back("-fobjc-dispatch-method=non-legacy");
+    }
+  }
+
+  // -fobjc-default-synthesize-properties=1 is default. This only has an effect
+  // if the nonfragile objc abi is used.
+  if (getToolChain().IsObjCDefaultSynthPropertiesDefault()) {
+    CmdArgs.push_back("-fobjc-default-synthesize-properties");
+  }
+
+  // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
+  // NOTE: This logic is duplicated in ToolChains.cpp.
+  bool ARC = isObjCAutoRefCount(Args);
+  if (ARC) {
+    if (!getToolChain().SupportsObjCARC())
+      D.Diag(diag::err_arc_unsupported);
+
+    CmdArgs.push_back("-fobjc-arc");
+
+    // FIXME: It seems like this entire block, and several around it should be
+    // wrapped in isObjC, but for now we just use it here as this is where it
+    // was being used previously.
+    if (types::isCXX(InputType) && types::isObjC(InputType)) {
+      if (getToolChain().GetCXXStdlibType(Args) == ToolChain::CST_Libcxx)
+        CmdArgs.push_back("-fobjc-arc-cxxlib=libc++");
+      else
+        CmdArgs.push_back("-fobjc-arc-cxxlib=libstdc++");
+    }
+
+    // Allow the user to enable full exceptions code emission.
+    // We define off for Objective-CC, on for Objective-C++.
+    if (Args.hasFlag(options::OPT_fobjc_arc_exceptions,
+                     options::OPT_fno_objc_arc_exceptions,
+                     /*default*/ types::isCXX(InputType)))
+      CmdArgs.push_back("-fobjc-arc-exceptions");
+  }
+
+  // -fobjc-infer-related-result-type is the default, except in the Objective-C
+  // rewriter.
+  if (IsRewriter || IsModernRewriter)
+    CmdArgs.push_back("-fno-objc-infer-related-result-type");
+
+  // Handle -fobjc-gc and -fobjc-gc-only. They are exclusive, and -fobjc-gc-only
+  // takes precedence.
+  const Arg *GCArg = Args.getLastArg(options::OPT_fobjc_gc_only);
+  if (!GCArg)
+    GCArg = Args.getLastArg(options::OPT_fobjc_gc);
+  if (GCArg) {
+    if (ARC) {
+      D.Diag(diag::err_drv_objc_gc_arr)
+        << GCArg->getAsString(Args);
+    } else if (getToolChain().SupportsObjCGC()) {
+      GCArg->render(Args, CmdArgs);
+    } else {
+      // FIXME: We should move this to a hard error.
+      D.Diag(diag::warn_drv_objc_gc_unsupported)
+        << GCArg->getAsString(Args);
+    }
+  }
+
+  // Add exception args.
+  addExceptionArgs(Args, InputType, getToolChain().getTriple(),
+                   KernelOrKext, objcABIVersion, CmdArgs);
+
+  if (getToolChain().UseSjLjExceptions())
+    CmdArgs.push_back("-fsjlj-exceptions");
+
+  // C++ "sane" operator new.
+  if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
+                    options::OPT_fno_assume_sane_operator_new))
+    CmdArgs.push_back("-fno-assume-sane-operator-new");
+
+  // -fconstant-cfstrings is default, and may be subject to argument translation
+  // on Darwin.
+  if (!Args.hasFlag(options::OPT_fconstant_cfstrings,
+                    options::OPT_fno_constant_cfstrings) ||
+      !Args.hasFlag(options::OPT_mconstant_cfstrings,
+                    options::OPT_mno_constant_cfstrings))
+    CmdArgs.push_back("-fno-constant-cfstrings");
+
+  // -fshort-wchar default varies depending on platform; only
+  // pass if specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fshort_wchar))
+    A->render(Args, CmdArgs);
+
+  // -fno-pascal-strings is default, only pass non-default. If the tool chain
+  // happened to translate to -mpascal-strings, we want to back translate here.
+  //
+  // FIXME: This is gross; that translation should be pulled from the
+  // tool chain.
+  if (Args.hasFlag(options::OPT_fpascal_strings,
+                   options::OPT_fno_pascal_strings,
+                   false) ||
+      Args.hasFlag(options::OPT_mpascal_strings,
+                   options::OPT_mno_pascal_strings,
+                   false))
+    CmdArgs.push_back("-fpascal-strings");
+
+  // Honor -fpack-struct= and -fpack-struct, if given. Note that
+  // -fno-pack-struct doesn't apply to -fpack-struct=.
+  if (Arg *A = Args.getLastArg(options::OPT_fpack_struct_EQ)) {
+    CmdArgs.push_back("-fpack-struct");
+    CmdArgs.push_back(A->getValue(Args));
+  } else if (Args.hasFlag(options::OPT_fpack_struct,
+                          options::OPT_fno_pack_struct, false)) {
+    CmdArgs.push_back("-fpack-struct");
+    CmdArgs.push_back("1");
+  }
+
+  if (Args.hasArg(options::OPT_mkernel) ||
+      Args.hasArg(options::OPT_fapple_kext)) {
+    if (!Args.hasArg(options::OPT_fcommon))
+      CmdArgs.push_back("-fno-common");
+    Args.ClaimAllArgs(options::OPT_fno_common);
+  }
+
+  // -fcommon is default, only pass non-default.
+  else if (!Args.hasFlag(options::OPT_fcommon, options::OPT_fno_common))
+    CmdArgs.push_back("-fno-common");
+
+  // -fsigned-bitfields is default, and clang doesn't yet support
+  // -funsigned-bitfields.
+  if (!Args.hasFlag(options::OPT_fsigned_bitfields,
+                    options::OPT_funsigned_bitfields))
+    D.Diag(diag::warn_drv_clang_unsupported)
+      << Args.getLastArg(options::OPT_funsigned_bitfields)->getAsString(Args);
+
+  // -fsigned-bitfields is default, and clang doesn't support -fno-for-scope.
+  if (!Args.hasFlag(options::OPT_ffor_scope,
+                    options::OPT_fno_for_scope))
+    D.Diag(diag::err_drv_clang_unsupported)
+      << Args.getLastArg(options::OPT_fno_for_scope)->getAsString(Args);
+
+  // -fcaret-diagnostics is default.
+  if (!Args.hasFlag(options::OPT_fcaret_diagnostics,
+                    options::OPT_fno_caret_diagnostics, true))
+    CmdArgs.push_back("-fno-caret-diagnostics");
+
+  // -fdiagnostics-fixit-info is default, only pass non-default.
+  if (!Args.hasFlag(options::OPT_fdiagnostics_fixit_info,
+                    options::OPT_fno_diagnostics_fixit_info))
+    CmdArgs.push_back("-fno-diagnostics-fixit-info");
+
+  // Enable -fdiagnostics-show-option by default.
+  if (Args.hasFlag(options::OPT_fdiagnostics_show_option,
+                   options::OPT_fno_diagnostics_show_option))
+    CmdArgs.push_back("-fdiagnostics-show-option");
+
+  if (const Arg *A =
+        Args.getLastArg(options::OPT_fdiagnostics_show_category_EQ)) {
+    CmdArgs.push_back("-fdiagnostics-show-category");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (const Arg *A =
+        Args.getLastArg(options::OPT_fdiagnostics_format_EQ)) {
+    CmdArgs.push_back("-fdiagnostics-format");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
+  if (Arg *A = Args.getLastArg(
+      options::OPT_fdiagnostics_show_note_include_stack,
+      options::OPT_fno_diagnostics_show_note_include_stack)) {
+    if (A->getOption().matches(
+        options::OPT_fdiagnostics_show_note_include_stack))
+      CmdArgs.push_back("-fdiagnostics-show-note-include-stack");
+    else
+      CmdArgs.push_back("-fno-diagnostics-show-note-include-stack");
+  }
+
+  // Color diagnostics are the default, unless the terminal doesn't support
+  // them.
+  if (Args.hasFlag(options::OPT_fcolor_diagnostics,
+                   options::OPT_fno_color_diagnostics,
+                   llvm::sys::Process::StandardErrHasColors()))
+    CmdArgs.push_back("-fcolor-diagnostics");
+
+  if (!Args.hasFlag(options::OPT_fshow_source_location,
+                    options::OPT_fno_show_source_location))
+    CmdArgs.push_back("-fno-show-source-location");
+
+  if (!Args.hasFlag(options::OPT_fshow_column,
+                    options::OPT_fno_show_column,
+                    true))
+    CmdArgs.push_back("-fno-show-column");
+
+  if (!Args.hasFlag(options::OPT_fspell_checking,
+                    options::OPT_fno_spell_checking))
+    CmdArgs.push_back("-fno-spell-checking");
+
+
+  // Silently ignore -fasm-blocks for now.
+  (void) Args.hasFlag(options::OPT_fasm_blocks, options::OPT_fno_asm_blocks,
+                      false);
+
+  if (Arg *A = Args.getLastArg(options::OPT_fshow_overloads_EQ))
+    A->render(Args, CmdArgs);
+
+  // -fdollars-in-identifiers default varies depending on platform and
+  // language; only pass if specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fdollars_in_identifiers,
+                               options::OPT_fno_dollars_in_identifiers)) {
+    if (A->getOption().matches(options::OPT_fdollars_in_identifiers))
+      CmdArgs.push_back("-fdollars-in-identifiers");
+    else
+      CmdArgs.push_back("-fno-dollars-in-identifiers");
+  }
+
+  // -funit-at-a-time is default, and we don't support -fno-unit-at-a-time for
+  // practical purposes.
+  if (Arg *A = Args.getLastArg(options::OPT_funit_at_a_time,
+                               options::OPT_fno_unit_at_a_time)) {
+    if (A->getOption().matches(options::OPT_fno_unit_at_a_time))
+      D.Diag(diag::warn_drv_clang_unsupported) << A->getAsString(Args);
+  }
+
+  if (Args.hasFlag(options::OPT_fapple_pragma_pack,
+                   options::OPT_fno_apple_pragma_pack, false))
+    CmdArgs.push_back("-fapple-pragma-pack");
+
+  // Default to -fno-builtin-str{cat,cpy} on Darwin for ARM.
+  //
+  // FIXME: This is disabled until clang -cc1 supports -fno-builtin-foo. PR4941.
+#if 0
+  if (getToolChain().getTriple().isOSDarwin() &&
+      (getToolChain().getTriple().getArch() == llvm::Triple::arm ||
+       getToolChain().getTriple().getArch() == llvm::Triple::thumb)) {
+    if (!Args.hasArg(options::OPT_fbuiltin_strcat))
+      CmdArgs.push_back("-fno-builtin-strcat");
+    if (!Args.hasArg(options::OPT_fbuiltin_strcpy))
+      CmdArgs.push_back("-fno-builtin-strcpy");
+  }
+#endif
+
+  // Only allow -traditional or -traditional-cpp outside in preprocessing modes.
+  if (Arg *A = Args.getLastArg(options::OPT_traditional,
+                               options::OPT_traditional_cpp)) {
+    if (isa<PreprocessJobAction>(JA))
+      CmdArgs.push_back("-traditional-cpp");
+    else
+      D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_dM);
+  Args.AddLastArg(CmdArgs, options::OPT_dD);
+  
+  // Handle serialized diagnostics.
+  if (Arg *A = Args.getLastArg(options::OPT__serialize_diags)) {
+    CmdArgs.push_back("-serialize-diagnostic-file");
+    CmdArgs.push_back(Args.MakeArgString(A->getValue(Args)));
+  }
+
+  // Forward -Xclang arguments to -cc1, and -mllvm arguments to the LLVM option
+  // parser.
+  Args.AddAllArgValues(CmdArgs, options::OPT_Xclang);
+  for (arg_iterator it = Args.filtered_begin(options::OPT_mllvm),
+         ie = Args.filtered_end(); it != ie; ++it) {
+    (*it)->claim();
+
+    // We translate this by hand to the -cc1 argument, since nightly test uses
+    // it and developers have been trained to spell it with -mllvm.
+    if (StringRef((*it)->getValue(Args, 0)) == "-disable-llvm-optzns")
+      CmdArgs.push_back("-disable-llvm-optzns");
+    else
+      (*it)->render(Args, CmdArgs);
+  }
+
+  if (Output.getType() == types::TY_Dependencies) {
+    // Handled with other dependency code.
+  } else if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back("-x");
+    CmdArgs.push_back(types::getTypeName(II.getType()));
+    if (II.isFilename())
+      CmdArgs.push_back(II.getFilename());
+    else
+      II.getInputArg().renderAsInput(Args, CmdArgs);
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_undef);
+
+  const char *Exec = getToolChain().getDriver().getClangProgramPath();
+
+  // Optionally embed the -cc1 level arguments into the debug info, for build
+  // analysis.
+  if (getToolChain().UseDwarfDebugFlags()) {
+    ArgStringList OriginalArgs;
+    for (ArgList::const_iterator it = Args.begin(),
+           ie = Args.end(); it != ie; ++it)
+      (*it)->render(Args, OriginalArgs);
+
+    SmallString<256> Flags;
+    Flags += Exec;
+    for (unsigned i = 0, e = OriginalArgs.size(); i != e; ++i) {
+      Flags += " ";
+      Flags += OriginalArgs[i];
+    }
+    CmdArgs.push_back("-dwarf-debug-flags");
+    CmdArgs.push_back(Args.MakeArgString(Flags.str()));
+  }
+
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+
+  if (Arg *A = Args.getLastArg(options::OPT_pg))
+    if (Args.hasArg(options::OPT_fomit_frame_pointer))
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+        << "-fomit-frame-pointer" << A->getAsString(Args);
+
+  // Claim some arguments which clang supports automatically.
+
+  // -fpch-preprocess is used with gcc to add a special marker in the output to
+  // include the PCH file. Clang's PTH solution is completely transparent, so we
+  // do not need to deal with it at all.
+  Args.ClaimAllArgs(options::OPT_fpch_preprocess);
+
+  // Claim some arguments which clang doesn't support, but we don't
+  // care to warn the user about.
+  Args.ClaimAllArgs(options::OPT_clang_ignored_f_Group);
+  Args.ClaimAllArgs(options::OPT_clang_ignored_m_Group);
+
+  // Disable warnings for clang -E -use-gold-plugin -emit-llvm foo.c
+  Args.ClaimAllArgs(options::OPT_use_gold_plugin);
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+}
+
+void ClangAs::AddARMTargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+  llvm::Triple Triple = getToolChain().getTriple();
+
+  // Set the CPU based on -march= and -mcpu=.
+  CmdArgs.push_back("-target-cpu");
+  CmdArgs.push_back(getARMTargetCPU(Args, Triple));
+
+  // Honor -mfpu=.
+  if (const Arg *A = Args.getLastArg(options::OPT_mfpu_EQ))
+    addFPUArgs(D, A, Args, CmdArgs);
+
+  // Honor -mfpmath=.
+  if (const Arg *A = Args.getLastArg(options::OPT_mfpmath_EQ))
+    addFPMathArgs(D, A, Args, CmdArgs, getARMTargetCPU(Args, Triple));
+}
+
+void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
+                           const InputInfo &Output,
+                           const InputInfoList &Inputs,
+                           const ArgList &Args,
+                           const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unexpected number of inputs.");
+  const InputInfo &Input = Inputs[0];
+
+  // Don't warn about "clang -w -c foo.s"
+  Args.ClaimAllArgs(options::OPT_w);
+  // and "clang -emit-llvm -c foo.s"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+  // and "clang -use-gold-plugin -c foo.s"
+  Args.ClaimAllArgs(options::OPT_use_gold_plugin);
+
+  // Invoke ourselves in -cc1as mode.
+  //
+  // FIXME: Implement custom jobs for internal actions.
+  CmdArgs.push_back("-cc1as");
+
+  // Add the "effective" target triple.
+  CmdArgs.push_back("-triple");
+  std::string TripleStr = 
+    getToolChain().ComputeEffectiveClangTriple(Args, Input.getType());
+  CmdArgs.push_back(Args.MakeArgString(TripleStr));
+
+  // Set the output mode, we currently only expect to be used as a real
+  // assembler.
+  CmdArgs.push_back("-filetype");
+  CmdArgs.push_back("obj");
+
+  if (UseRelaxAll(C, Args))
+    CmdArgs.push_back("-relax-all");
+
+  // Add target specific cpu and features flags.
+  switch(getToolChain().getTriple().getArch()) {
+  default:
+    break;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    AddARMTargetArgs(Args, CmdArgs);
+    break;
+  }
+
+  // Ignore explicit -force_cpusubtype_ALL option.
+  (void) Args.hasArg(options::OPT_force__cpusubtype__ALL);
+
+  // Determine the original source input.
+  const Action *SourceAction = &JA;
+  while (SourceAction->getKind() != Action::InputClass) {
+    assert(!SourceAction->getInputs().empty() && "unexpected root action!");
+    SourceAction = SourceAction->getInputs()[0];
+  }
+
+  // Forward -g, assuming we are dealing with an actual assembly file.
+  if (SourceAction->getType() == types::TY_Asm ||
+      SourceAction->getType() == types::TY_PP_Asm) {
+    Args.ClaimAllArgs(options::OPT_g_Group);
+    if (Arg *A = Args.getLastArg(options::OPT_g_Group))
+      if (!A->getOption().matches(options::OPT_g0))
+        CmdArgs.push_back("-g");
+  }
+
+  // Optionally embed the -cc1as level arguments into the debug info, for build
+  // analysis.
+  if (getToolChain().UseDwarfDebugFlags()) {
+    ArgStringList OriginalArgs;
+    for (ArgList::const_iterator it = Args.begin(),
+           ie = Args.end(); it != ie; ++it)
+      (*it)->render(Args, OriginalArgs);
+
+    SmallString<256> Flags;
+    const char *Exec = getToolChain().getDriver().getClangProgramPath();
+    Flags += Exec;
+    for (unsigned i = 0, e = OriginalArgs.size(); i != e; ++i) {
+      Flags += " ";
+      Flags += OriginalArgs[i];
+    }
+    CmdArgs.push_back("-dwarf-debug-flags");
+    CmdArgs.push_back(Args.MakeArgString(Flags.str()));
+  }
+
+  // FIXME: Add -static support, once we have it.
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+  Args.AddAllArgs(CmdArgs, options::OPT_mllvm);
+
+  assert(Output.isFilename() && "Unexpected lipo output.");
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  assert(Input.isFilename() && "Invalid input.");
+  CmdArgs.push_back(Input.getFilename());
+
+  const char *Exec = getToolChain().getDriver().getClangProgramPath();
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void gcc::Common::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &Args,
+                               const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  for (ArgList::const_iterator
+         it = Args.begin(), ie = Args.end(); it != ie; ++it) {
+    Arg *A = *it;
+    if (A->getOption().hasForwardToGCC()) {
+      // Don't forward any -g arguments to assembly steps.
+      if (isa<AssembleJobAction>(JA) &&
+          A->getOption().matches(options::OPT_g_Group))
+        continue;
+
+      // It is unfortunate that we have to claim here, as this means
+      // we will basically never report anything interesting for
+      // platforms using a generic gcc, even if we are just using gcc
+      // to get to the assembler.
+      A->claim();
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  RenderExtraToolArgs(JA, CmdArgs);
+
+  // If using a driver driver, force the arch.
+  const std::string &Arch = getToolChain().getArchName();
+  if (getToolChain().getTriple().isOSDarwin()) {
+    CmdArgs.push_back("-arch");
+
+    // FIXME: Remove these special cases.
+    if (Arch == "powerpc")
+      CmdArgs.push_back("ppc");
+    else if (Arch == "powerpc64")
+      CmdArgs.push_back("ppc64");
+    else
+      CmdArgs.push_back(Args.MakeArgString(Arch));
+  }
+
+  // Try to force gcc to match the tool chain we want, if we recognize
+  // the arch.
+  //
+  // FIXME: The triple class should directly provide the information we want
+  // here.
+  if (Arch == "i386" || Arch == "powerpc")
+    CmdArgs.push_back("-m32");
+  else if (Arch == "x86_64" || Arch == "powerpc64")
+    CmdArgs.push_back("-m64");
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Unexpected output");
+    CmdArgs.push_back("-fsyntax-only");
+  }
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  // Only pass -x if gcc will understand it; otherwise hope gcc
+  // understands the suffix correctly. The main use case this would go
+  // wrong in is for linker inputs if they happened to have an odd
+  // suffix; really the only way to get this to happen is a command
+  // like '-x foobar a.c' which will treat a.c like a linker input.
+  //
+  // FIXME: For the linker case specifically, can we safely convert
+  // inputs into '-Wl,' options?
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+
+    // Don't try to pass LLVM or AST inputs to a generic gcc.
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
+      D.Diag(diag::err_drv_no_linker_llvm_support)
+        << getToolChain().getTripleString();
+    else if (II.getType() == types::TY_AST)
+      D.Diag(diag::err_drv_no_ast_support)
+        << getToolChain().getTripleString();
+
+    if (types::canTypeBeUserSpecified(II.getType())) {
+      CmdArgs.push_back("-x");
+      CmdArgs.push_back(types::getTypeName(II.getType()));
+    }
+
+    if (II.isFilename())
+      CmdArgs.push_back(II.getFilename());
+    else {
+      const Arg &A = II.getInputArg();
+
+      // Reverse translate some rewritten options.
+      if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx)) {
+        CmdArgs.push_back("-lstdc++");
+        continue;
+      }
+
+      // Don't render as input, we need gcc to do the translations.
+      A.render(Args, CmdArgs);
+    }
+  }
+
+  const std::string customGCCName = D.getCCCGenericGCCName();
+  const char *GCCName;
+  if (!customGCCName.empty())
+    GCCName = customGCCName.c_str();
+  else if (D.CCCIsCXX) {
+    GCCName = "g++";
+  } else
+    GCCName = "gcc";
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath(GCCName));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void gcc::Preprocess::RenderExtraToolArgs(const JobAction &JA,
+                                          ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-E");
+}
+
+void gcc::Precompile::RenderExtraToolArgs(const JobAction &JA,
+                                          ArgStringList &CmdArgs) const {
+  // The type is good enough.
+}
+
+void gcc::Compile::RenderExtraToolArgs(const JobAction &JA,
+                                       ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  // If -flto, etc. are present then make sure not to force assembly output.
+  if (JA.getType() == types::TY_LLVM_IR || JA.getType() == types::TY_LTO_IR ||
+      JA.getType() == types::TY_LLVM_BC || JA.getType() == types::TY_LTO_BC)
+    CmdArgs.push_back("-c");
+  else {
+    if (JA.getType() != types::TY_PP_Asm)
+      D.Diag(diag::err_drv_invalid_gcc_output_type)
+        << getTypeName(JA.getType());
+
+    CmdArgs.push_back("-S");
+  }
+}
+
+void gcc::Assemble::RenderExtraToolArgs(const JobAction &JA,
+                                        ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-c");
+}
+
+void gcc::Link::RenderExtraToolArgs(const JobAction &JA,
+                                    ArgStringList &CmdArgs) const {
+  // The types are (hopefully) good enough.
+}
+
+// Hexagon tools start.
+void hexagon::Assemble::RenderExtraToolArgs(const JobAction &JA,
+                                        ArgStringList &CmdArgs) const {
+
+}
+void hexagon::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &Args,
+                               const char *LinkingOutput) const {
+
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  std::string MarchString = "-march=";
+  MarchString += getHexagonTargetCPU(Args);
+  CmdArgs.push_back(Args.MakeArgString(MarchString));
+
+  RenderExtraToolArgs(JA, CmdArgs);
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Unexpected output");
+    CmdArgs.push_back("-fsyntax-only");
+  }
+
+
+  // Only pass -x if gcc will understand it; otherwise hope gcc
+  // understands the suffix correctly. The main use case this would go
+  // wrong in is for linker inputs if they happened to have an odd
+  // suffix; really the only way to get this to happen is a command
+  // like '-x foobar a.c' which will treat a.c like a linker input.
+  //
+  // FIXME: For the linker case specifically, can we safely convert
+  // inputs into '-Wl,' options?
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+
+    // Don't try to pass LLVM or AST inputs to a generic gcc.
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
+      D.Diag(clang::diag::err_drv_no_linker_llvm_support)
+        << getToolChain().getTripleString();
+    else if (II.getType() == types::TY_AST)
+      D.Diag(clang::diag::err_drv_no_ast_support)
+        << getToolChain().getTripleString();
+
+    if (II.isFilename())
+      CmdArgs.push_back(II.getFilename());
+    else
+      // Don't render as input, we need gcc to do the translations. FIXME: Pranav: What is this ?
+      II.getInputArg().render(Args, CmdArgs);
+  }
+
+  const char *GCCName = "hexagon-as";
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath(GCCName));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+
+}
+void hexagon::Link::RenderExtraToolArgs(const JobAction &JA,
+                                    ArgStringList &CmdArgs) const {
+  // The types are (hopefully) good enough.
+}
+
+void hexagon::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &Args,
+                               const char *LinkingOutput) const {
+
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  for (ArgList::const_iterator
+         it = Args.begin(), ie = Args.end(); it != ie; ++it) {
+    Arg *A = *it;
+    if (A->getOption().hasForwardToGCC()) {
+      // Don't forward any -g arguments to assembly steps.
+      if (isa<AssembleJobAction>(JA) &&
+          A->getOption().matches(options::OPT_g_Group))
+        continue;
+
+      // It is unfortunate that we have to claim here, as this means
+      // we will basically never report anything interesting for
+      // platforms using a generic gcc, even if we are just using gcc
+      // to get to the assembler.
+      A->claim();
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  RenderExtraToolArgs(JA, CmdArgs);
+
+  // Add Arch Information
+  Arg *A;
+  if ((A = getLastHexagonArchArg(Args))) {
+    if (A->getOption().matches(options::OPT_m_Joined))
+      A->render(Args, CmdArgs);
+    else
+      CmdArgs.push_back (Args.MakeArgString("-m" + getHexagonTargetCPU(Args)));
+  }
+  else {
+    CmdArgs.push_back (Args.MakeArgString("-m" + getHexagonTargetCPU(Args)));
+  }
+
+  CmdArgs.push_back("-mqdsp6-compat");
+
+  const char *GCCName;
+  if (C.getDriver().CCCIsCXX)
+    GCCName = "hexagon-g++";
+  else
+    GCCName = "hexagon-gcc";
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath(GCCName));
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  }
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+
+    // Don't try to pass LLVM or AST inputs to a generic gcc.
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
+      D.Diag(clang::diag::err_drv_no_linker_llvm_support)
+        << getToolChain().getTripleString();
+    else if (II.getType() == types::TY_AST)
+      D.Diag(clang::diag::err_drv_no_ast_support)
+        << getToolChain().getTripleString();
+
+    if (II.isFilename())
+      CmdArgs.push_back(II.getFilename());
+    else
+      // Don't render as input, we need gcc to do the translations. FIXME: Pranav: What is this ?
+      II.getInputArg().render(Args, CmdArgs);
+  }
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+
+}
+// Hexagon tools end.
+
+
+const char *darwin::CC1::getCC1Name(types::ID Type) const {
+  switch (Type) {
+  default:
+    llvm_unreachable("Unexpected type for Darwin CC1 tool.");
+  case types::TY_Asm:
+  case types::TY_C: case types::TY_CHeader:
+  case types::TY_PP_C: case types::TY_PP_CHeader:
+    return "cc1";
+  case types::TY_ObjC: case types::TY_ObjCHeader:
+  case types::TY_PP_ObjC: case types::TY_PP_ObjC_Alias:
+  case types::TY_PP_ObjCHeader:
+    return "cc1obj";
+  case types::TY_CXX: case types::TY_CXXHeader:
+  case types::TY_PP_CXX: case types::TY_PP_CXXHeader:
+    return "cc1plus";
+  case types::TY_ObjCXX: case types::TY_ObjCXXHeader:
+  case types::TY_PP_ObjCXX: case types::TY_PP_ObjCXX_Alias:
+  case types::TY_PP_ObjCXXHeader:
+    return "cc1objplus";
+  }
+}
+
+void darwin::CC1::anchor() {}
+
+const char *darwin::CC1::getBaseInputName(const ArgList &Args,
+                                          const InputInfoList &Inputs) {
+  return Args.MakeArgString(
+    llvm::sys::path::filename(Inputs[0].getBaseInput()));
+}
+
+const char *darwin::CC1::getBaseInputStem(const ArgList &Args,
+                                          const InputInfoList &Inputs) {
+  const char *Str = getBaseInputName(Args, Inputs);
+
+  if (const char *End = strrchr(Str, '.'))
+    return Args.MakeArgString(std::string(Str, End));
+
+  return Str;
+}
+
+const char *
+darwin::CC1::getDependencyFileName(const ArgList &Args,
+                                   const InputInfoList &Inputs) {
+  // FIXME: Think about this more.
+  std::string Res;
+
+  if (Arg *OutputOpt = Args.getLastArg(options::OPT_o)) {
+    std::string Str(OutputOpt->getValue(Args));
+    Res = Str.substr(0, Str.rfind('.'));
+  } else {
+    Res = darwin::CC1::getBaseInputStem(Args, Inputs);
+  }
+  return Args.MakeArgString(Res + ".d");
+}
+
+void darwin::CC1::RemoveCC1UnsupportedArgs(ArgStringList &CmdArgs) const {
+  for (ArgStringList::iterator it = CmdArgs.begin(), ie = CmdArgs.end();
+       it != ie;) {
+
+    StringRef Option = *it;
+    bool RemoveOption = false;
+
+    // Erase both -fmodule-cache-path and its argument.
+    if (Option.equals("-fmodule-cache-path") && it+2 != ie) {
+      it = CmdArgs.erase(it, it+2);
+      ie = CmdArgs.end();
+      continue;
+    }
+
+    // Remove unsupported -f options.
+    if (Option.startswith("-f")) {
+      // Remove -f/-fno- to reduce the number of cases.
+      if (Option.startswith("-fno-"))
+        Option = Option.substr(5);
+      else
+        Option = Option.substr(2);
+      RemoveOption = llvm::StringSwitch<bool>(Option)
+        .Case("altivec", true)
+        .Case("modules", true)
+        .Case("diagnostics-show-note-include-stack", true)
+        .Default(false);
+    }
+
+    // Handle machine specific options.
+    if (Option.startswith("-m")) {
+      RemoveOption = llvm::StringSwitch<bool>(Option)
+        .Case("-mthumb", true)
+        .Case("-mno-thumb", true)
+        .Case("-mno-fused-madd", true)
+        .Case("-mlong-branch", true)
+        .Case("-mlongcall", true)
+        .Case("-mcpu=G4", true)
+        .Case("-mcpu=G5", true)
+        .Default(false);
+    }
+    
+    // Handle warning options.
+    if (Option.startswith("-W")) {
+      // Remove -W/-Wno- to reduce the number of cases.
+      if (Option.startswith("-Wno-"))
+        Option = Option.substr(5);
+      else
+        Option = Option.substr(2);
+      
+      RemoveOption = llvm::StringSwitch<bool>(Option)
+        .Case("address-of-temporary", true)
+        .Case("ambiguous-member-template", true)
+        .Case("analyzer-incompatible-plugin", true)
+        .Case("array-bounds", true)
+        .Case("array-bounds-pointer-arithmetic", true)
+        .Case("bind-to-temporary-copy", true)
+        .Case("bitwise-op-parentheses", true)
+        .Case("bool-conversions", true)
+        .Case("builtin-macro-redefined", true)
+        .Case("c++-hex-floats", true)
+        .Case("c++0x-compat", true)
+        .Case("c++0x-extensions", true)
+        .Case("c++0x-narrowing", true)
+        .Case("c++11-compat", true)
+        .Case("c++11-extensions", true)
+        .Case("c++11-narrowing", true)
+        .Case("conditional-uninitialized", true)
+        .Case("constant-conversion", true)
+        .Case("conversion-null", true)
+        .Case("CFString-literal", true)
+        .Case("constant-logical-operand", true)
+        .Case("custom-atomic-properties", true)
+        .Case("default-arg-special-member", true)
+        .Case("delegating-ctor-cycles", true)
+        .Case("delete-non-virtual-dtor", true)
+        .Case("deprecated-implementations", true)
+        .Case("deprecated-writable-strings", true)
+        .Case("distributed-object-modifiers", true)
+        .Case("duplicate-method-arg", true)
+        .Case("dynamic-class-memaccess", true)
+        .Case("enum-compare", true)
+        .Case("exit-time-destructors", true)
+        .Case("gnu", true)
+        .Case("gnu-designator", true)
+        .Case("header-hygiene", true)
+        .Case("idiomatic-parentheses", true)
+        .Case("ignored-qualifiers", true)
+        .Case("implicit-atomic-properties", true)
+        .Case("incompatible-pointer-types", true)
+        .Case("incomplete-implementation", true)
+        .Case("initializer-overrides", true)
+        .Case("invalid-noreturn", true)
+        .Case("invalid-token-paste", true)
+        .Case("language-extension-token", true)
+        .Case("literal-conversion", true)
+        .Case("literal-range", true)
+        .Case("local-type-template-args", true)
+        .Case("logical-op-parentheses", true)
+        .Case("method-signatures", true)
+        .Case("microsoft", true)
+        .Case("mismatched-tags", true)
+        .Case("missing-method-return-type", true)
+        .Case("non-pod-varargs", true)
+        .Case("nonfragile-abi2", true)
+        .Case("null-arithmetic", true)
+        .Case("null-dereference", true)
+        .Case("out-of-line-declaration", true)
+        .Case("overriding-method-mismatch", true)
+        .Case("readonly-setter-attrs", true)
+        .Case("return-stack-address", true)
+        .Case("self-assign", true)
+        .Case("semicolon-before-method-body", true)
+        .Case("sentinel", true)
+        .Case("shift-overflow", true)
+        .Case("shift-sign-overflow", true)
+        .Case("sign-conversion", true)
+        .Case("sizeof-array-argument", true)
+        .Case("sizeof-pointer-memaccess", true)
+        .Case("string-compare", true)
+        .Case("super-class-method-mismatch", true)
+        .Case("tautological-compare", true)
+        .Case("typedef-redefinition", true)
+        .Case("typename-missing", true)
+        .Case("undefined-reinterpret-cast", true)
+        .Case("unknown-warning-option", true)
+        .Case("unnamed-type-template-args", true)
+        .Case("unneeded-internal-declaration", true)
+        .Case("unneeded-member-function", true)
+        .Case("unused-comparison", true)
+        .Case("unused-exception-parameter", true)
+        .Case("unused-member-function", true)
+        .Case("unused-result", true)
+        .Case("vector-conversions", true)
+        .Case("vla", true)
+        .Case("used-but-marked-unused", true)
+        .Case("weak-vtables", true)
+        .Default(false);
+    } // if (Option.startswith("-W"))
+    if (RemoveOption) {
+      it = CmdArgs.erase(it);
+      ie = CmdArgs.end();
+    } else {
+      ++it;
+    }
+  }
+}
+
+void darwin::CC1::AddCC1Args(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  CheckCodeGenerationOptions(D, Args);
+
+  // Derived from cc1 spec.
+  if (!Args.hasArg(options::OPT_mkernel) && !Args.hasArg(options::OPT_static) &&
+      !Args.hasArg(options::OPT_mdynamic_no_pic))
+    CmdArgs.push_back("-fPIC");
+
+  if (getToolChain().getTriple().getArch() == llvm::Triple::arm ||
+      getToolChain().getTriple().getArch() == llvm::Triple::thumb) {
+    if (!Args.hasArg(options::OPT_fbuiltin_strcat))
+      CmdArgs.push_back("-fno-builtin-strcat");
+    if (!Args.hasArg(options::OPT_fbuiltin_strcpy))
+      CmdArgs.push_back("-fno-builtin-strcpy");
+  }
+
+  if (Args.hasArg(options::OPT_g_Flag) &&
+      !Args.hasArg(options::OPT_fno_eliminate_unused_debug_symbols))
+    CmdArgs.push_back("-feliminate-unused-debug-symbols");
+}
+
+void darwin::CC1::AddCC1OptionsArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                                    const InputInfoList &Inputs,
+                                    const ArgStringList &OutputArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  // Derived from cc1_options spec.
+  if (Args.hasArg(options::OPT_fast) ||
+      Args.hasArg(options::OPT_fastf) ||
+      Args.hasArg(options::OPT_fastcp))
+    CmdArgs.push_back("-O3");
+
+  if (Arg *A = Args.getLastArg(options::OPT_pg))
+    if (Args.hasArg(options::OPT_fomit_frame_pointer))
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+        << A->getAsString(Args) << "-fomit-frame-pointer";
+
+  AddCC1Args(Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_Q))
+    CmdArgs.push_back("-quiet");
+
+  CmdArgs.push_back("-dumpbase");
+  CmdArgs.push_back(darwin::CC1::getBaseInputName(Args, Inputs));
+
+  Args.AddAllArgs(CmdArgs, options::OPT_d_Group);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_m_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_a_Group);
+
+  // FIXME: The goal is to use the user provided -o if that is our
+  // final output, otherwise to drive from the original input
+  // name. Find a clean way to go about this.
+  if ((Args.hasArg(options::OPT_c) || Args.hasArg(options::OPT_S)) &&
+      Args.hasArg(options::OPT_o)) {
+    Arg *OutputOpt = Args.getLastArg(options::OPT_o);
+    CmdArgs.push_back("-auxbase-strip");
+    CmdArgs.push_back(OutputOpt->getValue(Args));
+  } else {
+    CmdArgs.push_back("-auxbase");
+    CmdArgs.push_back(darwin::CC1::getBaseInputStem(Args, Inputs));
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_g_Group);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_O);
+  // FIXME: -Wall is getting some special treatment. Investigate.
+  Args.AddAllArgs(CmdArgs, options::OPT_W_Group, options::OPT_pedantic_Group);
+  Args.AddLastArg(CmdArgs, options::OPT_w);
+  Args.AddAllArgs(CmdArgs, options::OPT_std_EQ, options::OPT_ansi,
+                  options::OPT_trigraphs);
+  if (!Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi)) {
+    // Honor -std-default.
+    Args.AddAllArgsTranslated(CmdArgs, options::OPT_std_default_EQ,
+                              "-std=", /*Joined=*/true);
+  }
+
+  if (Args.hasArg(options::OPT_v))
+    CmdArgs.push_back("-version");
+  if (Args.hasArg(options::OPT_pg) &&
+      getToolChain().SupportsProfiling())
+    CmdArgs.push_back("-p");
+  Args.AddLastArg(CmdArgs, options::OPT_p);
+
+  // The driver treats -fsyntax-only specially.
+  if (getToolChain().getTriple().getArch() == llvm::Triple::arm ||
+      getToolChain().getTriple().getArch() == llvm::Triple::thumb) {
+    // Removes -fbuiltin-str{cat,cpy}; these aren't recognized by cc1 but are
+    // used to inhibit the default -fno-builtin-str{cat,cpy}.
+    //
+    // FIXME: Should we grow a better way to deal with "removing" args?
+    for (arg_iterator it = Args.filtered_begin(options::OPT_f_Group,
+                                               options::OPT_fsyntax_only),
+           ie = Args.filtered_end(); it != ie; ++it) {
+      if (!(*it)->getOption().matches(options::OPT_fbuiltin_strcat) &&
+          !(*it)->getOption().matches(options::OPT_fbuiltin_strcpy)) {
+        (*it)->claim();
+        (*it)->render(Args, CmdArgs);
+      }
+    }
+  } else
+    Args.AddAllArgs(CmdArgs, options::OPT_f_Group, options::OPT_fsyntax_only);
+
+  // Claim Clang only -f options, they aren't worth warning about.
+  Args.ClaimAllArgs(options::OPT_f_clang_Group);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_undef);
+  if (Args.hasArg(options::OPT_Qn))
+    CmdArgs.push_back("-fno-ident");
+
+  // FIXME: This isn't correct.
+  //Args.AddLastArg(CmdArgs, options::OPT__help)
+  //Args.AddLastArg(CmdArgs, options::OPT__targetHelp)
+
+  CmdArgs.append(OutputArgs.begin(), OutputArgs.end());
+
+  // FIXME: Still don't get what is happening here. Investigate.
+  Args.AddAllArgs(CmdArgs, options::OPT__param);
+
+  if (Args.hasArg(options::OPT_fmudflap) ||
+      Args.hasArg(options::OPT_fmudflapth)) {
+    CmdArgs.push_back("-fno-builtin");
+    CmdArgs.push_back("-fno-merge-constants");
+  }
+
+  if (Args.hasArg(options::OPT_coverage)) {
+    CmdArgs.push_back("-fprofile-arcs");
+    CmdArgs.push_back("-ftest-coverage");
+  }
+
+  if (types::isCXX(Inputs[0].getType()))
+    CmdArgs.push_back("-D__private_extern__=extern");
+}
+
+void darwin::CC1::AddCPPOptionsArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                                    const InputInfoList &Inputs,
+                                    const ArgStringList &OutputArgs) const {
+  // Derived from cpp_options
+  AddCPPUniqueOptionsArgs(Args, CmdArgs, Inputs);
+
+  CmdArgs.append(OutputArgs.begin(), OutputArgs.end());
+
+  AddCC1Args(Args, CmdArgs);
+
+  // NOTE: The code below has some commonality with cpp_options, but
+  // in classic gcc style ends up sending things in different
+  // orders. This may be a good merge candidate once we drop pedantic
+  // compatibility.
+
+  Args.AddAllArgs(CmdArgs, options::OPT_m_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_std_EQ, options::OPT_ansi,
+                  options::OPT_trigraphs);
+  if (!Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi)) {
+    // Honor -std-default.
+    Args.AddAllArgsTranslated(CmdArgs, options::OPT_std_default_EQ,
+                              "-std=", /*Joined=*/true);
+  }
+  Args.AddAllArgs(CmdArgs, options::OPT_W_Group, options::OPT_pedantic_Group);
+  Args.AddLastArg(CmdArgs, options::OPT_w);
+
+  // The driver treats -fsyntax-only specially.
+  Args.AddAllArgs(CmdArgs, options::OPT_f_Group, options::OPT_fsyntax_only);
+
+  // Claim Clang only -f options, they aren't worth warning about.
+  Args.ClaimAllArgs(options::OPT_f_clang_Group);
+
+  if (Args.hasArg(options::OPT_g_Group) && !Args.hasArg(options::OPT_g0) &&
+      !Args.hasArg(options::OPT_fno_working_directory))
+    CmdArgs.push_back("-fworking-directory");
+
+  Args.AddAllArgs(CmdArgs, options::OPT_O);
+  Args.AddAllArgs(CmdArgs, options::OPT_undef);
+  if (Args.hasArg(options::OPT_save_temps))
+    CmdArgs.push_back("-fpch-preprocess");
+}
+
+void darwin::CC1::AddCPPUniqueOptionsArgs(const ArgList &Args,
+                                          ArgStringList &CmdArgs,
+                                          const InputInfoList &Inputs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  CheckPreprocessingOptions(D, Args);
+
+  // Derived from cpp_unique_options.
+  // -{C,CC} only with -E is checked in CheckPreprocessingOptions().
+  Args.AddLastArg(CmdArgs, options::OPT_C);
+  Args.AddLastArg(CmdArgs, options::OPT_CC);
+  if (!Args.hasArg(options::OPT_Q))
+    CmdArgs.push_back("-quiet");
+  Args.AddAllArgs(CmdArgs, options::OPT_nostdinc);
+  Args.AddAllArgs(CmdArgs, options::OPT_nostdincxx);
+  Args.AddLastArg(CmdArgs, options::OPT_v);
+  Args.AddAllArgs(CmdArgs, options::OPT_I_Group, options::OPT_F);
+  Args.AddLastArg(CmdArgs, options::OPT_P);
+
+  // FIXME: Handle %I properly.
+  if (getToolChain().getArchName() == "x86_64") {
+    CmdArgs.push_back("-imultilib");
+    CmdArgs.push_back("x86_64");
+  }
+
+  if (Args.hasArg(options::OPT_MD)) {
+    CmdArgs.push_back("-MD");
+    CmdArgs.push_back(darwin::CC1::getDependencyFileName(Args, Inputs));
+  }
+
+  if (Args.hasArg(options::OPT_MMD)) {
+    CmdArgs.push_back("-MMD");
+    CmdArgs.push_back(darwin::CC1::getDependencyFileName(Args, Inputs));
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_M);
+  Args.AddLastArg(CmdArgs, options::OPT_MM);
+  Args.AddAllArgs(CmdArgs, options::OPT_MF);
+  Args.AddLastArg(CmdArgs, options::OPT_MG);
+  Args.AddLastArg(CmdArgs, options::OPT_MP);
+  Args.AddAllArgs(CmdArgs, options::OPT_MQ);
+  Args.AddAllArgs(CmdArgs, options::OPT_MT);
+  if (!Args.hasArg(options::OPT_M) && !Args.hasArg(options::OPT_MM) &&
+      (Args.hasArg(options::OPT_MD) || Args.hasArg(options::OPT_MMD))) {
+    if (Arg *OutputOpt = Args.getLastArg(options::OPT_o)) {
+      CmdArgs.push_back("-MQ");
+      CmdArgs.push_back(OutputOpt->getValue(Args));
+    }
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_remap);
+  if (Args.hasArg(options::OPT_g3))
+    CmdArgs.push_back("-dD");
+  Args.AddLastArg(CmdArgs, options::OPT_H);
+
+  AddCPPArgs(Args, CmdArgs);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_D, options::OPT_U, options::OPT_A);
+  Args.AddAllArgs(CmdArgs, options::OPT_i_Group);
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wp_COMMA,
+                       options::OPT_Xpreprocessor);
+
+  if (Args.hasArg(options::OPT_fmudflap)) {
+    CmdArgs.push_back("-D_MUDFLAP");
+    CmdArgs.push_back("-include");
+    CmdArgs.push_back("mf-runtime.h");
+  }
+
+  if (Args.hasArg(options::OPT_fmudflapth)) {
+    CmdArgs.push_back("-D_MUDFLAP");
+    CmdArgs.push_back("-D_MUDFLAPTH");
+    CmdArgs.push_back("-include");
+    CmdArgs.push_back("mf-runtime.h");
+  }
+}
+
+void darwin::CC1::AddCPPArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  // Derived from cpp spec.
+
+  if (Args.hasArg(options::OPT_static)) {
+    // The gcc spec is broken here, it refers to dynamic but
+    // that has been translated. Start by being bug compatible.
+
+    // if (!Args.hasArg(arglist.parser.dynamicOption))
+    CmdArgs.push_back("-D__STATIC__");
+  } else
+    CmdArgs.push_back("-D__DYNAMIC__");
+
+  if (Args.hasArg(options::OPT_pthread))
+    CmdArgs.push_back("-D_REENTRANT");
+}
+
+void darwin::Preprocess::ConstructJob(Compilation &C, const JobAction &JA,
+                                      const InputInfo &Output,
+                                      const InputInfoList &Inputs,
+                                      const ArgList &Args,
+                                      const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unexpected number of inputs!");
+
+  CmdArgs.push_back("-E");
+
+  if (Args.hasArg(options::OPT_traditional) ||
+      Args.hasArg(options::OPT_traditional_cpp))
+    CmdArgs.push_back("-traditional-cpp");
+
+  ArgStringList OutputArgs;
+  assert(Output.isFilename() && "Unexpected CC1 output.");
+  OutputArgs.push_back("-o");
+  OutputArgs.push_back(Output.getFilename());
+
+  if (Args.hasArg(options::OPT_E) || getToolChain().getDriver().CCCIsCPP) {
+    AddCPPOptionsArgs(Args, CmdArgs, Inputs, OutputArgs);
+  } else {
+    AddCPPOptionsArgs(Args, CmdArgs, Inputs, ArgStringList());
+    CmdArgs.append(OutputArgs.begin(), OutputArgs.end());
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_d_Group);
+
+  RemoveCC1UnsupportedArgs(CmdArgs);
+
+  const char *CC1Name = getCC1Name(Inputs[0].getType());
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath(CC1Name));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::Compile::ConstructJob(Compilation &C, const JobAction &JA,
+                                   const InputInfo &Output,
+                                   const InputInfoList &Inputs,
+                                   const ArgList &Args,
+                                   const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unexpected number of inputs!");
+
+  // Silence warning about unused --serialize-diagnostics
+  Args.ClaimAllArgs(options::OPT__serialize_diags);
+
+  types::ID InputType = Inputs[0].getType();
+  if (const Arg *A = Args.getLastArg(options::OPT_traditional))
+    D.Diag(diag::err_drv_argument_only_allowed_with)
+      << A->getAsString(Args) << "-E";
+
+  if (JA.getType() == types::TY_LLVM_IR ||
+      JA.getType() == types::TY_LTO_IR)
+    CmdArgs.push_back("-emit-llvm");
+  else if (JA.getType() == types::TY_LLVM_BC ||
+           JA.getType() == types::TY_LTO_BC)
+    CmdArgs.push_back("-emit-llvm-bc");
+  else if (Output.getType() == types::TY_AST)
+    D.Diag(diag::err_drv_no_ast_support)
+      << getToolChain().getTripleString();
+  else if (JA.getType() != types::TY_PP_Asm &&
+           JA.getType() != types::TY_PCH)
+    D.Diag(diag::err_drv_invalid_gcc_output_type)
+      << getTypeName(JA.getType());
+
+  ArgStringList OutputArgs;
+  if (Output.getType() != types::TY_PCH) {
+    OutputArgs.push_back("-o");
+    if (Output.isNothing())
+      OutputArgs.push_back("/dev/null");
+    else
+      OutputArgs.push_back(Output.getFilename());
+  }
+
+  // There is no need for this level of compatibility, but it makes
+  // diffing easier.
+  bool OutputArgsEarly = (Args.hasArg(options::OPT_fsyntax_only) ||
+                          Args.hasArg(options::OPT_S));
+
+  if (types::getPreprocessedType(InputType) != types::TY_INVALID) {
+    AddCPPUniqueOptionsArgs(Args, CmdArgs, Inputs);
+    if (OutputArgsEarly) {
+      AddCC1OptionsArgs(Args, CmdArgs, Inputs, OutputArgs);
+    } else {
+      AddCC1OptionsArgs(Args, CmdArgs, Inputs, ArgStringList());
+      CmdArgs.append(OutputArgs.begin(), OutputArgs.end());
+    }
+  } else {
+    CmdArgs.push_back("-fpreprocessed");
+
+    for (InputInfoList::const_iterator
+           it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+      const InputInfo &II = *it;
+
+      // Reject AST inputs.
+      if (II.getType() == types::TY_AST) {
+        D.Diag(diag::err_drv_no_ast_support)
+          << getToolChain().getTripleString();
+        return;
+      }
+
+      CmdArgs.push_back(II.getFilename());
+    }
+
+    if (OutputArgsEarly) {
+      AddCC1OptionsArgs(Args, CmdArgs, Inputs, OutputArgs);
+    } else {
+      AddCC1OptionsArgs(Args, CmdArgs, Inputs, ArgStringList());
+      CmdArgs.append(OutputArgs.begin(), OutputArgs.end());
+    }
+  }
+
+  if (Output.getType() == types::TY_PCH) {
+    assert(Output.isFilename() && "Invalid PCH output.");
+
+    CmdArgs.push_back("-o");
+    // NOTE: gcc uses a temp .s file for this, but there doesn't seem
+    // to be a good reason.
+    const char *TmpPath = C.getArgs().MakeArgString(
+      D.GetTemporaryPath("cc", "s"));
+    C.addTempFile(TmpPath);
+    CmdArgs.push_back(TmpPath);
+
+    // If we're emitting a pch file with the last 4 characters of ".pth"
+    // and falling back to llvm-gcc we want to use ".gch" instead.
+    std::string OutputFile(Output.getFilename());
+    size_t loc = OutputFile.rfind(".pth");
+    if (loc != std::string::npos)
+      OutputFile.replace(loc, 4, ".gch");
+    const char *Tmp = C.getArgs().MakeArgString("--output-pch="+OutputFile);
+    CmdArgs.push_back(Tmp);
+  }
+
+  RemoveCC1UnsupportedArgs(CmdArgs);
+
+  const char *CC1Name = getCC1Name(Inputs[0].getType());
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath(CC1Name));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                    const InputInfo &Output,
+                                    const InputInfoList &Inputs,
+                                    const ArgList &Args,
+                                    const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unexpected number of inputs.");
+  const InputInfo &Input = Inputs[0];
+
+  // Determine the original source input.
+  const Action *SourceAction = &JA;
+  while (SourceAction->getKind() != Action::InputClass) {
+    assert(!SourceAction->getInputs().empty() && "unexpected root action!");
+    SourceAction = SourceAction->getInputs()[0];
+  }
+
+  // Forward -g, assuming we are dealing with an actual assembly file.
+  if (SourceAction->getType() == types::TY_Asm ||
+      SourceAction->getType() == types::TY_PP_Asm) {
+    if (Args.hasArg(options::OPT_gstabs))
+      CmdArgs.push_back("--gstabs");
+    else if (Args.hasArg(options::OPT_g_Group))
+      CmdArgs.push_back("-g");
+  }
+
+  // Derived from asm spec.
+  AddDarwinArch(Args, CmdArgs);
+
+  // Use -force_cpusubtype_ALL on x86 by default.
+  if (getToolChain().getTriple().getArch() == llvm::Triple::x86 ||
+      getToolChain().getTriple().getArch() == llvm::Triple::x86_64 ||
+      Args.hasArg(options::OPT_force__cpusubtype__ALL))
+    CmdArgs.push_back("-force_cpusubtype_ALL");
+
+  if (getToolChain().getTriple().getArch() != llvm::Triple::x86_64 &&
+      (Args.hasArg(options::OPT_mkernel) ||
+       Args.hasArg(options::OPT_static) ||
+       Args.hasArg(options::OPT_fapple_kext)))
+    CmdArgs.push_back("-static");
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  assert(Output.isFilename() && "Unexpected lipo output.");
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  assert(Input.isFilename() && "Invalid input.");
+  CmdArgs.push_back(Input.getFilename());
+
+  // asm_final spec is empty.
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::DarwinTool::anchor() {}
+
+void darwin::DarwinTool::AddDarwinArch(const ArgList &Args,
+                                       ArgStringList &CmdArgs) const {
+  StringRef ArchName = getDarwinToolChain().getDarwinArchName(Args);
+
+  // Derived from darwin_arch spec.
+  CmdArgs.push_back("-arch");
+  CmdArgs.push_back(Args.MakeArgString(ArchName));
+
+  // FIXME: Is this needed anymore?
+  if (ArchName == "arm")
+    CmdArgs.push_back("-force_cpusubtype_ALL");
+}
+
+void darwin::Link::AddLinkArgs(Compilation &C,
+                               const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+  const toolchains::Darwin &DarwinTC = getDarwinToolChain();
+
+  unsigned Version[3] = { 0, 0, 0 };
+  if (Arg *A = Args.getLastArg(options::OPT_mlinker_version_EQ)) {
+    bool HadExtra;
+    if (!Driver::GetReleaseVersion(A->getValue(Args), Version[0],
+                                   Version[1], Version[2], HadExtra) ||
+        HadExtra)
+      D.Diag(diag::err_drv_invalid_version_number)
+        << A->getAsString(Args);
+  }
+
+  // Newer linkers support -demangle, pass it if supported and not disabled by
+  // the user.
+  if (Version[0] >= 100 && !Args.hasArg(options::OPT_Z_Xlinker__no_demangle)) {
+    // Don't pass -demangle to ld_classic.
+    //
+    // FIXME: This is a temporary workaround, ld should be handling this.
+    bool UsesLdClassic = (getToolChain().getArch() == llvm::Triple::x86 &&
+                          Args.hasArg(options::OPT_static));
+    if (getToolChain().getArch() == llvm::Triple::x86) {
+      for (arg_iterator it = Args.filtered_begin(options::OPT_Xlinker,
+                                                 options::OPT_Wl_COMMA),
+             ie = Args.filtered_end(); it != ie; ++it) {
+        const Arg *A = *it;
+        for (unsigned i = 0, e = A->getNumValues(); i != e; ++i)
+          if (StringRef(A->getValue(Args, i)) == "-kext")
+            UsesLdClassic = true;
+      }
+    }
+    if (!UsesLdClassic)
+      CmdArgs.push_back("-demangle");
+  }
+
+  // If we are using LTO, then automatically create a temporary file path for
+  // the linker to use, so that it's lifetime will extend past a possible
+  // dsymutil step.
+  if (Version[0] >= 116 && D.IsUsingLTO(Args)) {
+    const char *TmpPath = C.getArgs().MakeArgString(
+      D.GetTemporaryPath("cc", types::getTypeTempSuffix(types::TY_Object)));
+    C.addTempFile(TmpPath);
+    CmdArgs.push_back("-object_path_lto");
+    CmdArgs.push_back(TmpPath);
+  }
+
+  // Derived from the "link" spec.
+  Args.AddAllArgs(CmdArgs, options::OPT_static);
+  if (!Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-dynamic");
+  if (Args.hasArg(options::OPT_fgnu_runtime)) {
+    // FIXME: gcc replaces -lobjc in forward args with -lobjc-gnu
+    // here. How do we wish to handle such things?
+  }
+
+  if (!Args.hasArg(options::OPT_dynamiclib)) {
+    AddDarwinArch(Args, CmdArgs);
+    // FIXME: Why do this only on this path?
+    Args.AddLastArg(CmdArgs, options::OPT_force__cpusubtype__ALL);
+
+    Args.AddLastArg(CmdArgs, options::OPT_bundle);
+    Args.AddAllArgs(CmdArgs, options::OPT_bundle__loader);
+    Args.AddAllArgs(CmdArgs, options::OPT_client__name);
+
+    Arg *A;
+    if ((A = Args.getLastArg(options::OPT_compatibility__version)) ||
+        (A = Args.getLastArg(options::OPT_current__version)) ||
+        (A = Args.getLastArg(options::OPT_install__name)))
+      D.Diag(diag::err_drv_argument_only_allowed_with)
+        << A->getAsString(Args) << "-dynamiclib";
+
+    Args.AddLastArg(CmdArgs, options::OPT_force__flat__namespace);
+    Args.AddLastArg(CmdArgs, options::OPT_keep__private__externs);
+    Args.AddLastArg(CmdArgs, options::OPT_private__bundle);
+  } else {
+    CmdArgs.push_back("-dylib");
+
+    Arg *A;
+    if ((A = Args.getLastArg(options::OPT_bundle)) ||
+        (A = Args.getLastArg(options::OPT_bundle__loader)) ||
+        (A = Args.getLastArg(options::OPT_client__name)) ||
+        (A = Args.getLastArg(options::OPT_force__flat__namespace)) ||
+        (A = Args.getLastArg(options::OPT_keep__private__externs)) ||
+        (A = Args.getLastArg(options::OPT_private__bundle)))
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+        << A->getAsString(Args) << "-dynamiclib";
+
+    Args.AddAllArgsTranslated(CmdArgs, options::OPT_compatibility__version,
+                              "-dylib_compatibility_version");
+    Args.AddAllArgsTranslated(CmdArgs, options::OPT_current__version,
+                              "-dylib_current_version");
+
+    AddDarwinArch(Args, CmdArgs);
+
+    Args.AddAllArgsTranslated(CmdArgs, options::OPT_install__name,
+                              "-dylib_install_name");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_all__load);
+  Args.AddAllArgs(CmdArgs, options::OPT_allowable__client);
+  Args.AddLastArg(CmdArgs, options::OPT_bind__at__load);
+  if (DarwinTC.isTargetIPhoneOS())
+    Args.AddLastArg(CmdArgs, options::OPT_arch__errors__fatal);
+  Args.AddLastArg(CmdArgs, options::OPT_dead__strip);
+  Args.AddLastArg(CmdArgs, options::OPT_no__dead__strip__inits__and__terms);
+  Args.AddAllArgs(CmdArgs, options::OPT_dylib__file);
+  Args.AddLastArg(CmdArgs, options::OPT_dynamic);
+  Args.AddAllArgs(CmdArgs, options::OPT_exported__symbols__list);
+  Args.AddLastArg(CmdArgs, options::OPT_flat__namespace);
+  Args.AddAllArgs(CmdArgs, options::OPT_force__load);
+  Args.AddAllArgs(CmdArgs, options::OPT_headerpad__max__install__names);
+  Args.AddAllArgs(CmdArgs, options::OPT_image__base);
+  Args.AddAllArgs(CmdArgs, options::OPT_init);
+
+  // Add the deployment target.
+  VersionTuple TargetVersion = DarwinTC.getTargetVersion();
+
+  // If we had an explicit -mios-simulator-version-min argument, honor that,
+  // otherwise use the traditional deployment targets. We can't just check the
+  // is-sim attribute because existing code follows this path, and the linker
+  // may not handle the argument.
+  //
+  // FIXME: We may be able to remove this, once we can verify no one depends on
+  // it.
+  if (Args.hasArg(options::OPT_mios_simulator_version_min_EQ))
+    CmdArgs.push_back("-ios_simulator_version_min");
+  else if (DarwinTC.isTargetIPhoneOS())
+    CmdArgs.push_back("-iphoneos_version_min");
+  else
+    CmdArgs.push_back("-macosx_version_min");
+  CmdArgs.push_back(Args.MakeArgString(TargetVersion.getAsString()));
+
+  Args.AddLastArg(CmdArgs, options::OPT_nomultidefs);
+  Args.AddLastArg(CmdArgs, options::OPT_multi__module);
+  Args.AddLastArg(CmdArgs, options::OPT_single__module);
+  Args.AddAllArgs(CmdArgs, options::OPT_multiply__defined);
+  Args.AddAllArgs(CmdArgs, options::OPT_multiply__defined__unused);
+
+  if (const Arg *A = Args.getLastArg(options::OPT_fpie, options::OPT_fPIE,
+                                     options::OPT_fno_pie,
+                                     options::OPT_fno_PIE)) {
+    if (A->getOption().matches(options::OPT_fpie) ||
+        A->getOption().matches(options::OPT_fPIE))
+      CmdArgs.push_back("-pie");
+    else
+      CmdArgs.push_back("-no_pie");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_prebind);
+  Args.AddLastArg(CmdArgs, options::OPT_noprebind);
+  Args.AddLastArg(CmdArgs, options::OPT_nofixprebinding);
+  Args.AddLastArg(CmdArgs, options::OPT_prebind__all__twolevel__modules);
+  Args.AddLastArg(CmdArgs, options::OPT_read__only__relocs);
+  Args.AddAllArgs(CmdArgs, options::OPT_sectcreate);
+  Args.AddAllArgs(CmdArgs, options::OPT_sectorder);
+  Args.AddAllArgs(CmdArgs, options::OPT_seg1addr);
+  Args.AddAllArgs(CmdArgs, options::OPT_segprot);
+  Args.AddAllArgs(CmdArgs, options::OPT_segaddr);
+  Args.AddAllArgs(CmdArgs, options::OPT_segs__read__only__addr);
+  Args.AddAllArgs(CmdArgs, options::OPT_segs__read__write__addr);
+  Args.AddAllArgs(CmdArgs, options::OPT_seg__addr__table);
+  Args.AddAllArgs(CmdArgs, options::OPT_seg__addr__table__filename);
+  Args.AddAllArgs(CmdArgs, options::OPT_sub__library);
+  Args.AddAllArgs(CmdArgs, options::OPT_sub__umbrella);
+
+  // Give --sysroot= preference, over the Apple specific behavior to also use
+  // --isysroot as the syslibroot.
+  StringRef sysroot = C.getSysRoot();
+  if (sysroot != "") {
+    CmdArgs.push_back("-syslibroot");
+    CmdArgs.push_back(C.getArgs().MakeArgString(sysroot));
+  } else if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
+    CmdArgs.push_back("-syslibroot");
+    CmdArgs.push_back(A->getValue(Args));
+  } else if (getDarwinToolChain().isTargetIPhoneOS()) {
+    CmdArgs.push_back("-syslibroot");
+    CmdArgs.push_back("/Developer/SDKs/Extra");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_twolevel__namespace);
+  Args.AddLastArg(CmdArgs, options::OPT_twolevel__namespace__hints);
+  Args.AddAllArgs(CmdArgs, options::OPT_umbrella);
+  Args.AddAllArgs(CmdArgs, options::OPT_undefined);
+  Args.AddAllArgs(CmdArgs, options::OPT_unexported__symbols__list);
+  Args.AddAllArgs(CmdArgs, options::OPT_weak__reference__mismatches);
+  Args.AddLastArg(CmdArgs, options::OPT_X_Flag);
+  Args.AddAllArgs(CmdArgs, options::OPT_y);
+  Args.AddLastArg(CmdArgs, options::OPT_w);
+  Args.AddAllArgs(CmdArgs, options::OPT_pagezero__size);
+  Args.AddAllArgs(CmdArgs, options::OPT_segs__read__);
+  Args.AddLastArg(CmdArgs, options::OPT_seglinkedit);
+  Args.AddLastArg(CmdArgs, options::OPT_noseglinkedit);
+  Args.AddAllArgs(CmdArgs, options::OPT_sectalign);
+  Args.AddAllArgs(CmdArgs, options::OPT_sectobjectsymbols);
+  Args.AddAllArgs(CmdArgs, options::OPT_segcreate);
+  Args.AddLastArg(CmdArgs, options::OPT_whyload);
+  Args.AddLastArg(CmdArgs, options::OPT_whatsloaded);
+  Args.AddAllArgs(CmdArgs, options::OPT_dylinker__install__name);
+  Args.AddLastArg(CmdArgs, options::OPT_dylinker);
+  Args.AddLastArg(CmdArgs, options::OPT_Mach);
+}
+
+void darwin::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                const InputInfo &Output,
+                                const InputInfoList &Inputs,
+                                const ArgList &Args,
+                                const char *LinkingOutput) const {
+  assert(Output.getType() == types::TY_Image && "Invalid linker output type.");
+
+  // The logic here is derived from gcc's behavior; most of which
+  // comes from specs (starting with link_command). Consult gcc for
+  // more information.
+  ArgStringList CmdArgs;
+
+  /// Hack(tm) to ignore linking errors when we are doing ARC migration.
+  if (Args.hasArg(options::OPT_ccc_arcmt_check,
+                  options::OPT_ccc_arcmt_migrate)) {
+    for (ArgList::const_iterator I = Args.begin(), E = Args.end(); I != E; ++I)
+      (*I)->claim();
+    const char *Exec =
+      Args.MakeArgString(getToolChain().GetProgramPath("touch"));
+    CmdArgs.push_back(Output.getFilename());
+    C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+    return;
+  }
+
+  // I'm not sure why this particular decomposition exists in gcc, but
+  // we follow suite for ease of comparison.
+  AddLinkArgs(C, Args, CmdArgs);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_d_Flag);
+  Args.AddAllArgs(CmdArgs, options::OPT_s);
+  Args.AddAllArgs(CmdArgs, options::OPT_t);
+  Args.AddAllArgs(CmdArgs, options::OPT_Z_Flag);
+  Args.AddAllArgs(CmdArgs, options::OPT_u_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_A);
+  Args.AddLastArg(CmdArgs, options::OPT_e);
+  Args.AddAllArgs(CmdArgs, options::OPT_m_Separate);
+  Args.AddAllArgs(CmdArgs, options::OPT_r);
+
+  // Forward -ObjC when either -ObjC or -ObjC++ is used, to force loading
+  // members of static archive libraries which implement Objective-C classes or
+  // categories.
+  if (Args.hasArg(options::OPT_ObjC) || Args.hasArg(options::OPT_ObjCXX))
+    CmdArgs.push_back("-ObjC");
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  if (!Args.hasArg(options::OPT_A) &&
+      !Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    // Derived from startfile spec.
+    if (Args.hasArg(options::OPT_dynamiclib)) {
+      // Derived from darwin_dylib1 spec.
+      if (getDarwinToolChain().isTargetIOSSimulator()) {
+        // The simulator doesn't have a versioned crt1 file.
+        CmdArgs.push_back("-ldylib1.o");
+      } else if (getDarwinToolChain().isTargetIPhoneOS()) {
+        if (getDarwinToolChain().isIPhoneOSVersionLT(3, 1))
+          CmdArgs.push_back("-ldylib1.o");
+      } else {
+        if (getDarwinToolChain().isMacosxVersionLT(10, 5))
+          CmdArgs.push_back("-ldylib1.o");
+        else if (getDarwinToolChain().isMacosxVersionLT(10, 6))
+          CmdArgs.push_back("-ldylib1.10.5.o");
+      }
+    } else {
+      if (Args.hasArg(options::OPT_bundle)) {
+        if (!Args.hasArg(options::OPT_static)) {
+          // Derived from darwin_bundle1 spec.
+          if (getDarwinToolChain().isTargetIOSSimulator()) {
+            // The simulator doesn't have a versioned crt1 file.
+            CmdArgs.push_back("-lbundle1.o");
+          } else if (getDarwinToolChain().isTargetIPhoneOS()) {
+            if (getDarwinToolChain().isIPhoneOSVersionLT(3, 1))
+              CmdArgs.push_back("-lbundle1.o");
+          } else {
+            if (getDarwinToolChain().isMacosxVersionLT(10, 6))
+              CmdArgs.push_back("-lbundle1.o");
+          }
+        }
+      } else {
+        if (Args.hasArg(options::OPT_pg) &&
+            getToolChain().SupportsProfiling()) {
+          if (Args.hasArg(options::OPT_static) ||
+              Args.hasArg(options::OPT_object) ||
+              Args.hasArg(options::OPT_preload)) {
+            CmdArgs.push_back("-lgcrt0.o");
+          } else {
+            CmdArgs.push_back("-lgcrt1.o");
+
+            // darwin_crt2 spec is empty.
+          }
+        } else {
+          if (Args.hasArg(options::OPT_static) ||
+              Args.hasArg(options::OPT_object) ||
+              Args.hasArg(options::OPT_preload)) {
+            CmdArgs.push_back("-lcrt0.o");
+          } else {
+            // Derived from darwin_crt1 spec.
+            if (getDarwinToolChain().isTargetIOSSimulator()) {
+              // The simulator doesn't have a versioned crt1 file.
+              CmdArgs.push_back("-lcrt1.o");
+            } else if (getDarwinToolChain().isTargetIPhoneOS()) {
+              if (getDarwinToolChain().isIPhoneOSVersionLT(3, 1))
+                CmdArgs.push_back("-lcrt1.o");
+              else
+                CmdArgs.push_back("-lcrt1.3.1.o");
+            } else {
+              if (getDarwinToolChain().isMacosxVersionLT(10, 5))
+                CmdArgs.push_back("-lcrt1.o");
+              else if (getDarwinToolChain().isMacosxVersionLT(10, 6))
+                CmdArgs.push_back("-lcrt1.10.5.o");
+              else if (getDarwinToolChain().isMacosxVersionLT(10, 8))
+                CmdArgs.push_back("-lcrt1.10.6.o");
+
+              // darwin_crt2 spec is empty.
+            }
+          }
+        }
+      }
+    }
+
+    if (!getDarwinToolChain().isTargetIPhoneOS() &&
+        Args.hasArg(options::OPT_shared_libgcc) &&
+        getDarwinToolChain().isMacosxVersionLT(10, 5)) {
+      const char *Str =
+        Args.MakeArgString(getToolChain().GetFilePath("crt3.o"));
+      CmdArgs.push_back(Str);
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+
+  // If we're building a dynamic lib with -faddress-sanitizer, unresolved
+  // symbols may appear. Mark all of them as dynamic_lookup.
+  // Linking executables is handled in lib/Driver/ToolChains.cpp.
+  if (Args.hasFlag(options::OPT_faddress_sanitizer,
+                   options::OPT_fno_address_sanitizer, false)) {
+    if (Args.hasArg(options::OPT_dynamiclib) ||
+        Args.hasArg(options::OPT_bundle)) {
+      CmdArgs.push_back("-undefined");
+      CmdArgs.push_back("dynamic_lookup");
+    }
+  }
+
+  if (Args.hasArg(options::OPT_fopenmp))
+    // This is more complicated in gcc...
+    CmdArgs.push_back("-lgomp");
+
+  getDarwinToolChain().AddLinkSearchPathArgs(Args, CmdArgs);
+
+  if (isObjCRuntimeLinked(Args)) {
+    // Avoid linking compatibility stubs on i386 mac.
+    if (!getDarwinToolChain().isTargetMacOS() ||
+        getDarwinToolChain().getArchName() != "i386") {
+      // If we don't have ARC or subscripting runtime support, link in the
+      // runtime stubs.  We have to do this *before* adding any of the normal
+      // linker inputs so that its initializer gets run first.
+      ObjCRuntime runtime;
+      getDarwinToolChain().configureObjCRuntime(runtime);
+      // We use arclite library for both ARC and subscripting support.
+      if ((!runtime.HasARC && isObjCAutoRefCount(Args)) ||
+          !runtime.HasSubscripting)
+        getDarwinToolChain().AddLinkARCArgs(Args, CmdArgs);
+      CmdArgs.push_back("-framework");
+      CmdArgs.push_back("Foundation");
+    }
+    // Link libobj.
+    CmdArgs.push_back("-lobjc");
+  }
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (LinkingOutput) {
+    CmdArgs.push_back("-arch_multiple");
+    CmdArgs.push_back("-final_output");
+    CmdArgs.push_back(LinkingOutput);
+  }
+
+  if (Args.hasArg(options::OPT_fnested_functions))
+    CmdArgs.push_back("-allow_stack_execute");
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (getToolChain().getDriver().CCCIsCXX)
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+
+    // link_ssp spec is empty.
+
+    // Let the tool chain choose which runtime library to link.
+    getDarwinToolChain().AddLinkRuntimeLibArgs(Args, CmdArgs);
+  }
+
+  if (!Args.hasArg(options::OPT_A) &&
+      !Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    // endfile_spec is empty.
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_F);
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::Lipo::ConstructJob(Compilation &C, const JobAction &JA,
+                                const InputInfo &Output,
+                                const InputInfoList &Inputs,
+                                const ArgList &Args,
+                                const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  CmdArgs.push_back("-create");
+  assert(Output.isFilename() && "Unexpected lipo output.");
+
+  CmdArgs.push_back("-output");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    assert(II.isFilename() && "Unexpected lipo input.");
+    CmdArgs.push_back(II.getFilename());
+  }
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("lipo"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::Dsymutil::ConstructJob(Compilation &C, const JobAction &JA,
+                                    const InputInfo &Output,
+                                    const InputInfoList &Inputs,
+                                    const ArgList &Args,
+                                    const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  assert(Inputs.size() == 1 && "Unable to handle multiple inputs.");
+  const InputInfo &Input = Inputs[0];
+  assert(Input.isFilename() && "Unexpected dsymutil input.");
+  CmdArgs.push_back(Input.getFilename());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("dsymutil"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void darwin::VerifyDebug::ConstructJob(Compilation &C, const JobAction &JA,
+				       const InputInfo &Output,
+				       const InputInfoList &Inputs,
+				       const ArgList &Args,
+				       const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+  CmdArgs.push_back("--verify");
+  CmdArgs.push_back("--debug-info");
+  CmdArgs.push_back("--eh-frame");
+  CmdArgs.push_back("--quiet");
+
+  assert(Inputs.size() == 1 && "Unable to handle multiple inputs.");
+  const InputInfo &Input = Inputs[0];
+  assert(Input.isFilename() && "Unexpected verify input");
+
+  // Grabbing the output of the earlier dsymutil run.
+  CmdArgs.push_back(Input.getFilename());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("dwarfdump"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void solaris::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                      const InputInfo &Output,
+                                      const InputInfoList &Inputs,
+                                      const ArgList &Args,
+                                      const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+
+void solaris::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+  // FIXME: Find a real GCC, don't hard-code versions here
+  std::string GCCLibPath = "/usr/gcc/4.5/lib/gcc/";
+  const llvm::Triple &T = getToolChain().getTriple();
+  std::string LibPath = "/usr/lib/";
+  llvm::Triple::ArchType Arch = T.getArch();
+  switch (Arch) {
+        case llvm::Triple::x86:
+          GCCLibPath += ("i386-" + T.getVendorName() + "-" +
+              T.getOSName()).str() + "/4.5.2/";
+          break;
+        case llvm::Triple::x86_64:
+          GCCLibPath += ("i386-" + T.getVendorName() + "-" +
+              T.getOSName()).str();
+          GCCLibPath += "/4.5.2/amd64/";
+          LibPath += "amd64/";
+          break;
+        default:
+          assert(0 && "Unsupported architecture");
+  }
+
+  ArgStringList CmdArgs;
+
+  // Demangle C++ names in errors
+  CmdArgs.push_back("-C");
+
+  if ((!Args.hasArg(options::OPT_nostdlib)) &&
+      (!Args.hasArg(options::OPT_shared))) {
+    CmdArgs.push_back("-e");
+    CmdArgs.push_back("_start");
+  }
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+    CmdArgs.push_back("-dn");
+  } else {
+    CmdArgs.push_back("-Bdynamic");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-shared");
+    } else {
+      CmdArgs.push_back("--dynamic-linker");
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "ld.so.1"));
+    }
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "crt1.o"));
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "crti.o"));
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "values-Xa.o"));
+      CmdArgs.push_back(Args.MakeArgString(GCCLibPath + "crtbegin.o"));
+    } else {
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "crti.o"));
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "values-Xa.o"));
+      CmdArgs.push_back(Args.MakeArgString(GCCLibPath + "crtbegin.o"));
+    }
+    if (getToolChain().getDriver().CCCIsCXX)
+      CmdArgs.push_back(Args.MakeArgString(LibPath + "cxa_finalize.o"));
+  }
+
+  CmdArgs.push_back(Args.MakeArgString("-L" + GCCLibPath));
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+  Args.AddAllArgs(CmdArgs, options::OPT_r);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (getToolChain().getDriver().CCCIsCXX)
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+    CmdArgs.push_back("-lgcc_s");
+    if (!Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-lgcc");
+      CmdArgs.push_back("-lc");
+      CmdArgs.push_back("-lm");
+    }
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    CmdArgs.push_back(Args.MakeArgString(GCCLibPath + "crtend.o"));
+  }
+  CmdArgs.push_back(Args.MakeArgString(LibPath + "crtn.o"));
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void auroraux::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                      const InputInfo &Output,
+                                      const InputInfoList &Inputs,
+                                      const ArgList &Args,
+                                      const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("gas"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void auroraux::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  if ((!Args.hasArg(options::OPT_nostdlib)) &&
+      (!Args.hasArg(options::OPT_shared))) {
+    CmdArgs.push_back("-e");
+    CmdArgs.push_back("_start");
+  }
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+    CmdArgs.push_back("-dn");
+  } else {
+//    CmdArgs.push_back("--eh-frame-hdr");
+    CmdArgs.push_back("-Bdynamic");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-shared");
+    } else {
+      CmdArgs.push_back("--dynamic-linker");
+      CmdArgs.push_back("/lib/ld.so.1"); // 64Bit Path /lib/amd64/ld.so.1
+    }
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crt1.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crti.o")));
+    }
+    CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crtn.o")));
+  }
+
+  CmdArgs.push_back(Args.MakeArgString("-L/opt/gcc4/lib/gcc/"
+                                       + getToolChain().getTripleString()
+                                       + "/4.2.4"));
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    // FIXME: For some reason GCC passes -lgcc before adding
+    // the default system libraries. Just mimic this for now.
+    CmdArgs.push_back("-lgcc");
+
+    if (Args.hasArg(options::OPT_pthread))
+      CmdArgs.push_back("-pthread");
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back("-lc");
+    CmdArgs.push_back("-lgcc");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crtend.o")));
+  }
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void openbsd::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                     const InputInfo &Output,
+                                     const InputInfoList &Inputs,
+                                     const ArgList &Args,
+                                     const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void openbsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                 const InputInfo &Output,
+                                 const InputInfoList &Inputs,
+                                 const ArgList &Args,
+                                 const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if ((!Args.hasArg(options::OPT_nostdlib)) &&
+      (!Args.hasArg(options::OPT_shared))) {
+    CmdArgs.push_back("-e");
+    CmdArgs.push_back("__start");
+  }
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    CmdArgs.push_back("--eh-frame-hdr");
+    CmdArgs.push_back("-Bdynamic");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-shared");
+    } else {
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/usr/libexec/ld.so");
+    }
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      if (Args.hasArg(options::OPT_pg))  
+        CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("gcrt0.o")));
+      else
+        CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("crt0.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbeginS.o")));
+    }
+  }
+
+  std::string Triple = getToolChain().getTripleString();
+  if (Triple.substr(0, 6) == "x86_64")
+    Triple.replace(0, 6, "amd64");
+  CmdArgs.push_back(Args.MakeArgString("-L/usr/lib/gcc-lib/" + Triple +
+                                       "/4.2.1"));
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (D.CCCIsCXX) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (Args.hasArg(options::OPT_pg)) 
+        CmdArgs.push_back("-lm_p");
+      else
+        CmdArgs.push_back("-lm");
+    }
+
+    // FIXME: For some reason GCC passes -lgcc before adding
+    // the default system libraries. Just mimic this for now.
+    CmdArgs.push_back("-lgcc");
+
+    if (Args.hasArg(options::OPT_pthread))
+      CmdArgs.push_back("-lpthread");
+    if (!Args.hasArg(options::OPT_shared)) {
+      if (Args.hasArg(options::OPT_pg)) 
+         CmdArgs.push_back("-lc_p");
+      else
+         CmdArgs.push_back("-lc");
+    }
+    CmdArgs.push_back("-lgcc");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtend.o")));
+    else
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtendS.o")));
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void freebsd::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                     const InputInfo &Output,
+                                     const InputInfoList &Inputs,
+                                     const ArgList &Args,
+                                     const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  // When building 32-bit code on FreeBSD/amd64, we have to explicitly
+  // instruct as in the base system to assemble 32-bit code.
+  if (getToolChain().getArchName() == "i386")
+    CmdArgs.push_back("--32");
+
+  if (getToolChain().getArchName() == "powerpc")
+    CmdArgs.push_back("-a32");
+
+  // Set byte order explicitly
+  if (getToolChain().getArchName() == "mips")
+    CmdArgs.push_back("-EB");
+  else if (getToolChain().getArchName() == "mipsel")
+    CmdArgs.push_back("-EL");
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void freebsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                 const InputInfo &Output,
+                                 const InputInfoList &Inputs,
+                                 const ArgList &Args,
+                                 const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    CmdArgs.push_back("--eh-frame-hdr");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-Bshareable");
+    } else {
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/libexec/ld-elf.so.1");
+    }
+  }
+
+  // When building 32-bit code on FreeBSD/amd64, we have to explicitly
+  // instruct ld in the base system to link 32-bit code.
+  if (getToolChain().getArchName() == "i386") {
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf_i386_fbsd");
+  }
+
+  if (getToolChain().getArchName() == "powerpc") {
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf32ppc_fbsd");
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath("gcrt1.o")));
+      else {
+        const char *crt = Args.hasArg(options::OPT_pie) ? "Scrt1.o" : "crt1.o";
+        CmdArgs.push_back(Args.MakeArgString(
+                                getToolChain().GetFilePath(crt)));
+      }
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbeginS.o")));
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  const ToolChain::path_list Paths = getToolChain().getFilePaths();
+  for (ToolChain::path_list::const_iterator i = Paths.begin(), e = Paths.end();
+       i != e; ++i)
+    CmdArgs.push_back(Args.MakeArgString(StringRef("-L") + *i));
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+  Args.AddAllArgs(CmdArgs, options::OPT_s);
+  Args.AddAllArgs(CmdArgs, options::OPT_t);
+  Args.AddAllArgs(CmdArgs, options::OPT_Z_Flag);
+  Args.AddAllArgs(CmdArgs, options::OPT_r);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (D.CCCIsCXX) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back("-lm_p");
+      else
+        CmdArgs.push_back("-lm");
+    }
+    // FIXME: For some reason GCC passes -lgcc and -lgcc_s before adding
+    // the default system libraries. Just mimic this for now.
+    if (Args.hasArg(options::OPT_pg))
+      CmdArgs.push_back("-lgcc_p");
+    else
+      CmdArgs.push_back("-lgcc");
+    if (Args.hasArg(options::OPT_static)) {
+      CmdArgs.push_back("-lgcc_eh");
+    } else if (Args.hasArg(options::OPT_pg)) {
+      CmdArgs.push_back("-lgcc_eh_p");
+    } else {
+      CmdArgs.push_back("--as-needed");
+      CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("--no-as-needed");
+    }
+
+    if (Args.hasArg(options::OPT_pthread)) {
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back("-lpthread_p");
+      else
+        CmdArgs.push_back("-lpthread");
+    }
+
+    if (Args.hasArg(options::OPT_pg)) {
+      if (Args.hasArg(options::OPT_shared))
+        CmdArgs.push_back("-lc");
+      else
+        CmdArgs.push_back("-lc_p");
+      CmdArgs.push_back("-lgcc_p");
+    } else {
+      CmdArgs.push_back("-lc");
+      CmdArgs.push_back("-lgcc");
+    }
+
+    if (Args.hasArg(options::OPT_static)) {
+      CmdArgs.push_back("-lgcc_eh");
+    } else if (Args.hasArg(options::OPT_pg)) {
+      CmdArgs.push_back("-lgcc_eh_p");
+    } else {
+      CmdArgs.push_back("--as-needed");
+      CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("--no-as-needed");
+    }
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                  "crtend.o")));
+    else
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                 "crtendS.o")));
+    CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                    "crtn.o")));
+  }
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void netbsd::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                     const InputInfo &Output,
+                                     const InputInfoList &Inputs,
+                                     const ArgList &Args,
+                                     const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  // When building 32-bit code on NetBSD/amd64, we have to explicitly
+  // instruct as in the base system to assemble 32-bit code.
+  if (getToolChain().getArch() == llvm::Triple::x86)
+    CmdArgs.push_back("--32");
+
+  // Set byte order explicitly
+  if (getToolChain().getArchName() == "mips")
+    CmdArgs.push_back("-EB");
+  else if (getToolChain().getArchName() == "mipsel")
+    CmdArgs.push_back("-EL");
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec = Args.MakeArgString((getToolChain().GetProgramPath("as")));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void netbsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                 const InputInfo &Output,
+                                 const InputInfoList &Inputs,
+                                 const ArgList &Args,
+                                 const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    CmdArgs.push_back("--eh-frame-hdr");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-Bshareable");
+    } else {
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/libexec/ld.elf_so");
+    }
+  }
+
+  // When building 32-bit code on NetBSD/amd64, we have to explicitly
+  // instruct ld in the base system to link 32-bit code.
+  if (getToolChain().getArch() == llvm::Triple::x86) {
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf_i386");
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crt0.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtbeginS.o")));
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+  Args.AddAllArgs(CmdArgs, options::OPT_s);
+  Args.AddAllArgs(CmdArgs, options::OPT_t);
+  Args.AddAllArgs(CmdArgs, options::OPT_Z_Flag);
+  Args.AddAllArgs(CmdArgs, options::OPT_r);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (D.CCCIsCXX) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      CmdArgs.push_back("-lm");
+    }
+    // FIXME: For some reason GCC passes -lgcc and -lgcc_s before adding
+    // the default system libraries. Just mimic this for now.
+    if (Args.hasArg(options::OPT_static)) {
+      CmdArgs.push_back("-lgcc_eh");
+    } else {
+      CmdArgs.push_back("--as-needed");
+      CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("--no-as-needed");
+    }
+    CmdArgs.push_back("-lgcc");
+
+    if (Args.hasArg(options::OPT_pthread))
+      CmdArgs.push_back("-lpthread");
+    CmdArgs.push_back("-lc");
+
+    CmdArgs.push_back("-lgcc");
+    if (Args.hasArg(options::OPT_static)) {
+      CmdArgs.push_back("-lgcc_eh");
+    } else {
+      CmdArgs.push_back("--as-needed");
+      CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("--no-as-needed");
+    }
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                  "crtend.o")));
+    else
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                 "crtendS.o")));
+    CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath(
+                                                                    "crtn.o")));
+  }
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void linuxtools::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                        const InputInfo &Output,
+                                        const InputInfoList &Inputs,
+                                        const ArgList &Args,
+                                        const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  // Add --32/--64 to make sure we get the format we want.
+  // This is incomplete
+  if (getToolChain().getArch() == llvm::Triple::x86) {
+    CmdArgs.push_back("--32");
+  } else if (getToolChain().getArch() == llvm::Triple::x86_64) {
+    CmdArgs.push_back("--64");
+  } else if (getToolChain().getArch() == llvm::Triple::ppc) {
+    CmdArgs.push_back("-a32");
+    CmdArgs.push_back("-mppc");
+    CmdArgs.push_back("-many");
+  } else if (getToolChain().getArch() == llvm::Triple::ppc64) {
+    CmdArgs.push_back("-a64");
+    CmdArgs.push_back("-mppc64");
+    CmdArgs.push_back("-many");
+  } else if (getToolChain().getArch() == llvm::Triple::arm) {
+    StringRef MArch = getToolChain().getArchName();
+    if (MArch == "armv7" || MArch == "armv7a" || MArch == "armv7-a")
+      CmdArgs.push_back("-mfpu=neon");
+  } else if (getToolChain().getArch() == llvm::Triple::mips ||
+             getToolChain().getArch() == llvm::Triple::mipsel ||
+             getToolChain().getArch() == llvm::Triple::mips64 ||
+             getToolChain().getArch() == llvm::Triple::mips64el) {
+    StringRef CPUName;
+    StringRef ABIName;
+    getMipsCPUAndABI(Args, getToolChain(), CPUName, ABIName);
+
+    CmdArgs.push_back("-march");
+    CmdArgs.push_back(CPUName.data());
+
+    // Convert ABI name to the GNU tools acceptable variant.
+    if (ABIName == "o32")
+      ABIName = "32";
+    else if (ABIName == "n64")
+      ABIName = "64";
+
+    CmdArgs.push_back("-mabi");
+    CmdArgs.push_back(ABIName.data());
+
+    if (getToolChain().getArch() == llvm::Triple::mips ||
+        getToolChain().getArch() == llvm::Triple::mips64)
+      CmdArgs.push_back("-EB");
+    else
+      CmdArgs.push_back("-EL");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
+  Args.AddLastArg(CmdArgs, options::OPT_mcpu_EQ);
+  Args.AddLastArg(CmdArgs, options::OPT_mfpu_EQ);
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+static void AddLibgcc(const Driver &D, ArgStringList &CmdArgs,
+                      const ArgList &Args) {
+  bool StaticLibgcc = Args.hasArg(options::OPT_static) ||
+    Args.hasArg(options::OPT_static_libgcc);
+  if (!D.CCCIsCXX)
+    CmdArgs.push_back("-lgcc");
+
+  if (StaticLibgcc) {
+    if (D.CCCIsCXX)
+      CmdArgs.push_back("-lgcc");
+  } else {
+    if (!D.CCCIsCXX)
+      CmdArgs.push_back("--as-needed");
+    CmdArgs.push_back("-lgcc_s");
+    if (!D.CCCIsCXX)
+      CmdArgs.push_back("--no-as-needed");
+  }
+
+  if (StaticLibgcc)
+    CmdArgs.push_back("-lgcc_eh");
+  else if (!Args.hasArg(options::OPT_shared) && D.CCCIsCXX)
+    CmdArgs.push_back("-lgcc");
+}
+
+void linuxtools::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                    const InputInfo &Output,
+                                    const InputInfoList &Inputs,
+                                    const ArgList &Args,
+                                    const char *LinkingOutput) const {
+  const toolchains::Linux& ToolChain =
+    static_cast<const toolchains::Linux&>(getToolChain());
+  const Driver &D = ToolChain.getDriver();
+  ArgStringList CmdArgs;
+
+  // Silence warning for "clang -g foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  // and "clang -emit-llvm foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+  // and for "clang -g foo.o -o foo". Other warning options are already
+  // handled somewhere else.
+  Args.ClaimAllArgs(options::OPT_w);
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (Args.hasArg(options::OPT_pie))
+    CmdArgs.push_back("-pie");
+
+  if (Args.hasArg(options::OPT_rdynamic))
+    CmdArgs.push_back("-export-dynamic");
+
+  if (Args.hasArg(options::OPT_s))
+    CmdArgs.push_back("-s");
+
+  for (std::vector<std::string>::const_iterator i = ToolChain.ExtraOpts.begin(),
+         e = ToolChain.ExtraOpts.end();
+       i != e; ++i)
+    CmdArgs.push_back(i->c_str());
+
+  if (!Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("--eh-frame-hdr");
+  }
+
+  CmdArgs.push_back("-m");
+  if (ToolChain.getArch() == llvm::Triple::x86)
+    CmdArgs.push_back("elf_i386");
+  else if (ToolChain.getArch() == llvm::Triple::arm
+           ||  ToolChain.getArch() == llvm::Triple::thumb)
+    CmdArgs.push_back("armelf_linux_eabi");
+  else if (ToolChain.getArch() == llvm::Triple::ppc)
+    CmdArgs.push_back("elf32ppclinux");
+  else if (ToolChain.getArch() == llvm::Triple::ppc64)
+    CmdArgs.push_back("elf64ppc");
+  else if (ToolChain.getArch() == llvm::Triple::mips)
+    CmdArgs.push_back("elf32btsmip");
+  else if (ToolChain.getArch() == llvm::Triple::mipsel)
+    CmdArgs.push_back("elf32ltsmip");
+  else if (ToolChain.getArch() == llvm::Triple::mips64)
+    CmdArgs.push_back("elf64btsmip");
+  else if (ToolChain.getArch() == llvm::Triple::mips64el)
+    CmdArgs.push_back("elf64ltsmip");
+  else
+    CmdArgs.push_back("elf_x86_64");
+
+  if (Args.hasArg(options::OPT_static)) {
+    if (ToolChain.getArch() == llvm::Triple::arm
+        || ToolChain.getArch() == llvm::Triple::thumb)
+      CmdArgs.push_back("-Bstatic");
+    else
+      CmdArgs.push_back("-static");
+  } else if (Args.hasArg(options::OPT_shared)) {
+    CmdArgs.push_back("-shared");
+  }
+
+  if (ToolChain.getArch() == llvm::Triple::arm ||
+      ToolChain.getArch() == llvm::Triple::thumb ||
+      (!Args.hasArg(options::OPT_static) &&
+       !Args.hasArg(options::OPT_shared))) {
+    CmdArgs.push_back("-dynamic-linker");
+    if (ToolChain.getArch() == llvm::Triple::x86)
+      CmdArgs.push_back("/lib/ld-linux.so.2");
+    else if (ToolChain.getArch() == llvm::Triple::arm ||
+             ToolChain.getArch() == llvm::Triple::thumb)
+      CmdArgs.push_back("/lib/ld-linux.so.3");
+    else if (ToolChain.getArch() == llvm::Triple::mips ||
+             ToolChain.getArch() == llvm::Triple::mipsel)
+      CmdArgs.push_back("/lib/ld.so.1");
+    else if (ToolChain.getArch() == llvm::Triple::mips64 ||
+             ToolChain.getArch() == llvm::Triple::mips64el)
+      CmdArgs.push_back("/lib64/ld.so.1");
+    else if (ToolChain.getArch() == llvm::Triple::ppc)
+      CmdArgs.push_back("/lib/ld.so.1");
+    else if (ToolChain.getArch() == llvm::Triple::ppc64)
+      CmdArgs.push_back("/lib64/ld64.so.1");
+    else
+      CmdArgs.push_back("/lib64/ld-linux-x86-64.so.2");
+  }
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    const char *crt1 = NULL;
+    if (!Args.hasArg(options::OPT_shared)){
+      if (Args.hasArg(options::OPT_pie))
+        crt1 = "Scrt1.o";
+      else
+        crt1 = "crt1.o";
+    }
+    if (crt1)
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crt1)));
+
+    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
+
+    const char *crtbegin;
+    if (Args.hasArg(options::OPT_static))
+      crtbegin = "crtbeginT.o";
+    else if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_pie))
+      crtbegin = "crtbeginS.o";
+    else
+      crtbegin = "crtbegin.o";
+    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtbegin)));
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+
+  const ToolChain::path_list Paths = ToolChain.getFilePaths();
+
+  for (ToolChain::path_list::const_iterator i = Paths.begin(), e = Paths.end();
+       i != e; ++i)
+    CmdArgs.push_back(Args.MakeArgString(StringRef("-L") + *i));
+
+  // Tell the linker to load the plugin. This has to come before AddLinkerInputs
+  // as gold requires -plugin to come before any -plugin-opt that -Wl might
+  // forward.
+  if (D.IsUsingLTO(Args) || Args.hasArg(options::OPT_use_gold_plugin)) {
+    CmdArgs.push_back("-plugin");
+    std::string Plugin = ToolChain.getDriver().Dir + "/../lib/LLVMgold.so";
+    CmdArgs.push_back(Args.MakeArgString(Plugin));
+  }
+
+  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
+
+  if (D.CCCIsCXX && !Args.hasArg(options::OPT_nostdlib)) {
+    bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+      !Args.hasArg(options::OPT_static);
+    if (OnlyLibstdcxxStatic)
+      CmdArgs.push_back("-Bstatic");
+    ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+    if (OnlyLibstdcxxStatic)
+      CmdArgs.push_back("-Bdynamic");
+    CmdArgs.push_back("-lm");
+  }
+
+  // Call this before we add the C run-time.
+  addAsanRTLinux(getToolChain(), Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib)) {
+    if (Args.hasArg(options::OPT_static))
+      CmdArgs.push_back("--start-group");
+
+    AddLibgcc(D, CmdArgs, Args);
+
+    if (Args.hasArg(options::OPT_pthread) ||
+        Args.hasArg(options::OPT_pthreads))
+      CmdArgs.push_back("-lpthread");
+
+    CmdArgs.push_back("-lc");
+
+    if (Args.hasArg(options::OPT_static))
+      CmdArgs.push_back("--end-group");
+    else
+      AddLibgcc(D, CmdArgs, Args);
+
+
+    if (!Args.hasArg(options::OPT_nostartfiles)) {
+      const char *crtend;
+      if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_pie))
+        crtend = "crtendS.o";
+      else
+        crtend = "crtend.o";
+
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtend)));
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
+    }
+  }
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  C.addCommand(new Command(JA, *this, ToolChain.Linker.c_str(), CmdArgs));
+}
+
+void minix::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                   const InputInfo &Output,
+                                   const InputInfoList &Inputs,
+                                   const ArgList &Args,
+                                   const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void minix::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &Args,
+                               const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath("crt1.o")));
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath("crtbegin.o")));
+      CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath("crtn.o")));
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    if (D.CCCIsCXX) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      CmdArgs.push_back("-lm");
+    }
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (Args.hasArg(options::OPT_pthread))
+      CmdArgs.push_back("-lpthread");
+    CmdArgs.push_back("-lc");
+    CmdArgs.push_back("-lCompilerRT-Generic");
+    CmdArgs.push_back("-L/usr/pkg/compiler-rt/lib");
+    CmdArgs.push_back(
+	 Args.MakeArgString(getToolChain().GetFilePath("crtend.o")));
+  }
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+/// DragonFly Tools
+
+// For now, DragonFly Assemble does just about the same as for
+// FreeBSD, but this may change soon.
+void dragonfly::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
+                                       const InputInfo &Output,
+                                       const InputInfoList &Inputs,
+                                       const ArgList &Args,
+                                       const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  // When building 32-bit code on DragonFly/pc64, we have to explicitly
+  // instruct as in the base system to assemble 32-bit code.
+  if (getToolChain().getArchName() == "i386")
+    CmdArgs.push_back("--32");
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
+                       options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    CmdArgs.push_back(II.getFilename());
+  }
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void dragonfly::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                   const InputInfo &Output,
+                                   const InputInfoList &Inputs,
+                                   const ArgList &Args,
+                                   const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back("-Bshareable");
+    else {
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/usr/libexec/ld-elf.so.2");
+    }
+  }
+
+  // When building 32-bit code on DragonFly/pc64, we have to explicitly
+  // instruct ld in the base system to link 32-bit code.
+  if (getToolChain().getArchName() == "i386") {
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf_i386");
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crt1.o")));
+      CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crti.o")));
+      CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crtbeginS.o")));
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
+  Args.AddAllArgs(CmdArgs, options::OPT_e);
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    // FIXME: GCC passes on -lgcc, -lgcc_pic and a whole lot of
+    //         rpaths
+    CmdArgs.push_back("-L/usr/lib/gcc41");
+
+    if (!Args.hasArg(options::OPT_static)) {
+      CmdArgs.push_back("-rpath");
+      CmdArgs.push_back("/usr/lib/gcc41");
+
+      CmdArgs.push_back("-rpath-link");
+      CmdArgs.push_back("/usr/lib/gcc41");
+
+      CmdArgs.push_back("-rpath");
+      CmdArgs.push_back("/usr/lib");
+
+      CmdArgs.push_back("-rpath-link");
+      CmdArgs.push_back("/usr/lib");
+    }
+
+    if (D.CCCIsCXX) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      CmdArgs.push_back("-lm");
+    }
+
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-lgcc_pic");
+    } else {
+      CmdArgs.push_back("-lgcc");
+    }
+
+
+    if (Args.hasArg(options::OPT_pthread))
+      CmdArgs.push_back("-lpthread");
+
+    if (!Args.hasArg(options::OPT_nolibc)) {
+      CmdArgs.push_back("-lc");
+    }
+
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-lgcc_pic");
+    } else {
+      CmdArgs.push_back("-lgcc");
+    }
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtend.o")));
+    else
+      CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtendS.o")));
+    CmdArgs.push_back(Args.MakeArgString(
+                              getToolChain().GetFilePath("crtn.o")));
+  }
+
+  addProfileRT(getToolChain(), Args, CmdArgs, getToolChain().getTriple());
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
+
+void visualstudio::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                      const InputInfo &Output,
+                                      const InputInfoList &Inputs,
+                                      const ArgList &Args,
+                                      const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back(Args.MakeArgString(std::string("-out:") +
+                                         Output.getFilename()));
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+    !Args.hasArg(options::OPT_nostartfiles)) {
+    CmdArgs.push_back("-defaultlib:libcmt");
+  }
+
+  CmdArgs.push_back("-nologo");
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);
+
+  const char *Exec =
+    Args.MakeArgString(getToolChain().GetProgramPath("link.exe"));
+  C.addCommand(new Command(JA, *this, Exec, CmdArgs));
+}
diff --git a/clang/lib/Driver/Tools.h b/clang/lib/Driver/Tools.h
new file mode 100644
index 0000000..651a8f2
--- /dev/null
+++ b/clang/lib/Driver/Tools.h
@@ -0,0 +1,605 @@
+//===--- Tools.h - Tool Implementations -------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLANG_LIB_DRIVER_TOOLS_H_
+#define CLANG_LIB_DRIVER_TOOLS_H_
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/Types.h"
+#include "clang/Driver/Util.h"
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/Compiler.h"
+
+namespace clang {
+namespace driver {
+  class Driver;
+
+namespace toolchains {
+  class Darwin;
+}
+
+namespace tools {
+
+  /// \brief Clang compiler tool.
+  class LLVM_LIBRARY_VISIBILITY Clang : public Tool {
+    void AddPreprocessingOptions(Compilation &C,
+                                 const Driver &D,
+                                 const ArgList &Args,
+                                 ArgStringList &CmdArgs,
+                                 const InputInfo &Output,
+                                 const InputInfoList &Inputs) const;
+
+    void AddARMTargetArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                          bool KernelOrKext) const;
+    void AddMIPSTargetArgs(const ArgList &Args, ArgStringList &CmdArgs) const;
+    void AddSparcTargetArgs(const ArgList &Args, ArgStringList &CmdArgs) const;
+    void AddX86TargetArgs(const ArgList &Args, ArgStringList &CmdArgs) const;
+    void AddHexagonTargetArgs (const ArgList &Args, ArgStringList &CmdArgs) const;
+
+  public:
+    Clang(const ToolChain &TC) : Tool("clang", "clang frontend", TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedAssembler() const { return true; }
+    virtual bool hasIntegratedCPP() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  /// \brief Clang integrated assembler tool.
+  class LLVM_LIBRARY_VISIBILITY ClangAs : public Tool {
+    void AddARMTargetArgs(const ArgList &Args, ArgStringList &CmdArgs) const;
+  public:
+    ClangAs(const ToolChain &TC) : Tool("clang::as",
+                                        "clang integrated assembler", TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedAssembler() const { return false; }
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  /// gcc - Generic GCC tool implementations.
+namespace gcc {
+  class LLVM_LIBRARY_VISIBILITY Common : public Tool {
+  public:
+    Common(const char *Name, const char *ShortName,
+           const ToolChain &TC) : Tool(Name, ShortName, TC) {}
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+
+    /// RenderExtraToolArgs - Render any arguments necessary to force
+    /// the particular tool mode.
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const = 0;
+  };
+
+
+  class LLVM_LIBRARY_VISIBILITY Preprocess : public Common {
+  public:
+    Preprocess(const ToolChain &TC) : Common("gcc::Preprocess",
+                                             "gcc preprocessor", TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Precompile : public Common  {
+  public:
+    Precompile(const ToolChain &TC) : Common("gcc::Precompile",
+                                             "gcc precompile", TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedCPP() const { return true; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Compile : public Common  {
+  public:
+    Compile(const ToolChain &TC) : Common("gcc::Compile",
+                                          "gcc frontend", TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedCPP() const { return true; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Common  {
+  public:
+    Assemble(const ToolChain &TC) : Common("gcc::Assemble",
+                                           "assembler (via gcc)", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Link : public Common  {
+  public:
+    Link(const ToolChain &TC) : Common("gcc::Link",
+                                       "linker (via gcc)", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+  };
+} // end namespace gcc
+
+namespace hexagon {
+  // For Hexagon, we do not need to instantiate tools for PreProcess, PreCompile and Compile.
+  // We simply use "clang -cc1" for those actions.
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool {
+  public:
+    Assemble(const ToolChain &TC) : Tool("hexagon::Assemble",
+      "hexagon-as", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool {
+  public:
+    Link(const ToolChain &TC) : Tool("hexagon::Link",
+      "hexagon-ld", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void RenderExtraToolArgs(const JobAction &JA,
+                                     ArgStringList &CmdArgs) const;
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace hexagon.
+
+
+namespace darwin {
+  class LLVM_LIBRARY_VISIBILITY DarwinTool : public Tool {
+    virtual void anchor();
+  protected:
+    void AddDarwinArch(const ArgList &Args, ArgStringList &CmdArgs) const;
+
+    const toolchains::Darwin &getDarwinToolChain() const {
+      return reinterpret_cast<const toolchains::Darwin&>(getToolChain());
+    }
+
+  public:
+    DarwinTool(const char *Name, const char *ShortName,
+               const ToolChain &TC) : Tool(Name, ShortName, TC) {}
+  };
+
+  class LLVM_LIBRARY_VISIBILITY CC1 : public DarwinTool  {
+    virtual void anchor();
+  public:
+    static const char *getBaseInputName(const ArgList &Args,
+                                 const InputInfoList &Input);
+    static const char *getBaseInputStem(const ArgList &Args,
+                                 const InputInfoList &Input);
+    static const char *getDependencyFileName(const ArgList &Args,
+                                             const InputInfoList &Inputs);
+
+  protected:
+    const char *getCC1Name(types::ID Type) const;
+
+    void AddCC1Args(const ArgList &Args, ArgStringList &CmdArgs) const;
+    void RemoveCC1UnsupportedArgs(ArgStringList &CmdArgs) const;
+    void AddCC1OptionsArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                           const InputInfoList &Inputs,
+                           const ArgStringList &OutputArgs) const;
+    void AddCPPOptionsArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                           const InputInfoList &Inputs,
+                           const ArgStringList &OutputArgs) const;
+    void AddCPPUniqueOptionsArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs,
+                                 const InputInfoList &Inputs) const;
+    void AddCPPArgs(const ArgList &Args, ArgStringList &CmdArgs) const;
+
+  public:
+    CC1(const char *Name, const char *ShortName,
+        const ToolChain &TC) : DarwinTool(Name, ShortName, TC) {}
+
+    virtual bool hasGoodDiagnostics() const { return true; }
+    virtual bool hasIntegratedCPP() const { return true; }
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Preprocess : public CC1  {
+  public:
+    Preprocess(const ToolChain &TC) : CC1("darwin::Preprocess",
+                                          "gcc preprocessor", TC) {}
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Compile : public CC1  {
+  public:
+    Compile(const ToolChain &TC) : CC1("darwin::Compile", "gcc frontend", TC) {}
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Assemble : public DarwinTool  {
+  public:
+    Assemble(const ToolChain &TC) : DarwinTool("darwin::Assemble",
+                                               "assembler", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Link : public DarwinTool  {
+    void AddLinkArgs(Compilation &C, const ArgList &Args,
+                     ArgStringList &CmdArgs) const;
+
+  public:
+    Link(const ToolChain &TC) : DarwinTool("darwin::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Lipo : public DarwinTool  {
+  public:
+    Lipo(const ToolChain &TC) : DarwinTool("darwin::Lipo", "lipo", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY Dsymutil : public DarwinTool  {
+  public:
+    Dsymutil(const ToolChain &TC) : DarwinTool("darwin::Dsymutil",
+                                               "dsymutil", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+
+  class LLVM_LIBRARY_VISIBILITY VerifyDebug : public DarwinTool  {
+  public:
+    VerifyDebug(const ToolChain &TC) : DarwinTool("darwin::VerifyDebug",
+						  "dwarfdump", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+			      const InputInfo &Output,
+			      const InputInfoList &Inputs,
+			      const ArgList &TCArgs,
+			      const char *LinkingOutput) const;
+  };
+
+}
+
+  /// openbsd -- Directly call GNU Binutils assembler and linker
+namespace openbsd {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("openbsd::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("openbsd::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace openbsd
+
+  /// freebsd -- Directly call GNU Binutils assembler and linker
+namespace freebsd {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("freebsd::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("freebsd::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace freebsd
+
+  /// netbsd -- Directly call GNU Binutils assembler and linker
+namespace netbsd {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+
+  public:
+    Assemble(const ToolChain &TC)
+      : Tool("netbsd::Assemble", "assembler", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+
+  public:
+    Link(const ToolChain &TC)
+      : Tool("netbsd::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace netbsd
+
+  /// linux -- Directly call GNU Binutils assembler and linker
+namespace linuxtools {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("linux::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("linux::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+}
+  /// minix -- Directly call GNU Binutils assembler and linker
+namespace minix {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("minix::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("minix::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace minix
+
+  /// solaris -- Directly call Solaris assembler and linker
+namespace solaris {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("solaris::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("solaris::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace solaris
+
+  /// auroraux -- Directly call GNU Binutils assembler and linker
+namespace auroraux {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("auroraux::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("auroraux::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace auroraux
+
+  /// dragonfly -- Directly call GNU Binutils assembler and linker
+namespace dragonfly {
+  class LLVM_LIBRARY_VISIBILITY Assemble : public Tool  {
+  public:
+    Assemble(const ToolChain &TC) : Tool("dragonfly::Assemble", "assembler",
+                                         TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("dragonfly::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace dragonfly
+
+  /// Visual studio tools.
+namespace visualstudio {
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("visualstudio::Link", "linker", TC) {}
+
+    virtual bool hasIntegratedCPP() const { return false; }
+    virtual bool isLinkJob() const { return true; }
+
+    virtual void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const ArgList &TCArgs,
+                              const char *LinkingOutput) const;
+  };
+} // end namespace visualstudio
+
+} // end namespace toolchains
+} // end namespace driver
+} // end namespace clang
+
+#endif // CLANG_LIB_DRIVER_TOOLS_H_
diff --git a/clang/lib/Driver/Types.cpp b/clang/lib/Driver/Types.cpp
new file mode 100644
index 0000000..50742fe
--- /dev/null
+++ b/clang/lib/Driver/Types.cpp
@@ -0,0 +1,254 @@
+//===--- Types.cpp - Driver input & temporary type information ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Types.h"
+
+#include "llvm/ADT/StringSwitch.h"
+#include <string.h>
+#include <cassert>
+
+using namespace clang::driver;
+using namespace clang::driver::types;
+
+struct TypeInfo {
+  const char *Name;
+  const char *Flags;
+  const char *TempSuffix;
+  ID PreprocessedType;
+};
+
+static const TypeInfo TypeInfos[] = {
+#define TYPE(NAME, ID, PP_TYPE, TEMP_SUFFIX, FLAGS) \
+  { NAME, FLAGS, TEMP_SUFFIX, TY_##PP_TYPE, },
+#include "clang/Driver/Types.def"
+#undef TYPE
+};
+static const unsigned numTypes = sizeof(TypeInfos) / sizeof(TypeInfos[0]);
+
+static const TypeInfo &getInfo(unsigned id) {
+  assert(id > 0 && id - 1 < numTypes && "Invalid Type ID.");
+  return TypeInfos[id - 1];
+}
+
+const char *types::getTypeName(ID Id) {
+  return getInfo(Id).Name;
+}
+
+types::ID types::getPreprocessedType(ID Id) {
+  return getInfo(Id).PreprocessedType;
+}
+
+const char *types::getTypeTempSuffix(ID Id) {
+  return getInfo(Id).TempSuffix;
+}
+
+bool types::onlyAssembleType(ID Id) {
+  return strchr(getInfo(Id).Flags, 'a');
+}
+
+bool types::onlyPrecompileType(ID Id) {
+  return strchr(getInfo(Id).Flags, 'p');
+}
+
+bool types::canTypeBeUserSpecified(ID Id) {
+  return strchr(getInfo(Id).Flags, 'u');
+}
+
+bool types::appendSuffixForType(ID Id) {
+  return strchr(getInfo(Id).Flags, 'A');
+}
+
+bool types::canLipoType(ID Id) {
+  return (Id == TY_Nothing ||
+          Id == TY_Image ||
+          Id == TY_Object);
+}
+
+bool types::isAcceptedByClang(ID Id) {
+  switch (Id) {
+  default:
+    return false;
+
+  case TY_Asm:
+  case TY_C: case TY_PP_C:
+  case TY_CL:
+  case TY_CUDA:
+  case TY_ObjC: case TY_PP_ObjC: case TY_PP_ObjC_Alias:
+  case TY_CXX: case TY_PP_CXX:
+  case TY_ObjCXX: case TY_PP_ObjCXX: case TY_PP_ObjCXX_Alias:
+  case TY_CHeader: case TY_PP_CHeader:
+  case TY_CLHeader:
+  case TY_ObjCHeader: case TY_PP_ObjCHeader:
+  case TY_CXXHeader: case TY_PP_CXXHeader:
+  case TY_ObjCXXHeader: case TY_PP_ObjCXXHeader:
+  case TY_AST:
+  case TY_LLVM_IR: case TY_LLVM_BC:
+    return true;
+  }
+}
+
+bool types::isOnlyAcceptedByClang(ID Id) {
+  switch (Id) {
+  default:
+    return false;
+
+  case TY_AST:
+  case TY_LLVM_IR:
+  case TY_LLVM_BC:
+  case TY_RewrittenObjC:
+  case TY_RewrittenLegacyObjC:
+    return true;
+  }
+}
+
+bool types::isObjC(ID Id) {
+  switch (Id) {
+  default:
+    return false;
+
+  case TY_ObjC: case TY_PP_ObjC: case TY_PP_ObjC_Alias:
+  case TY_ObjCXX: case TY_PP_ObjCXX:
+  case TY_ObjCHeader: case TY_PP_ObjCHeader:
+  case TY_ObjCXXHeader: case TY_PP_ObjCXXHeader: case TY_PP_ObjCXX_Alias:
+    return true;
+  }
+}
+
+bool types::isCXX(ID Id) {
+  switch (Id) {
+  default:
+    return false;
+
+  case TY_CXX: case TY_PP_CXX:
+  case TY_ObjCXX: case TY_PP_ObjCXX:
+  case TY_CXXHeader: case TY_PP_CXXHeader:
+  case TY_ObjCXXHeader: case TY_PP_ObjCXXHeader:
+    return true;
+  }
+}
+
+types::ID types::lookupTypeForExtension(const char *Ext) {
+  return llvm::StringSwitch<types::ID>(Ext)
+           .Case("c", TY_C)
+           .Case("i", TY_PP_C)
+           .Case("m", TY_ObjC)
+           .Case("M", TY_ObjCXX)
+           .Case("h", TY_CHeader)
+           .Case("C", TY_CXX)
+           .Case("H", TY_CXXHeader)
+           .Case("f", TY_PP_Fortran)
+           .Case("F", TY_Fortran)
+           .Case("s", TY_PP_Asm)
+           .Case("S", TY_Asm)
+           .Case("o", TY_Object)
+           .Case("ii", TY_PP_CXX)
+           .Case("mi", TY_PP_ObjC)
+           .Case("mm", TY_ObjCXX)
+           .Case("bc", TY_LLVM_BC)
+           .Case("cc", TY_CXX)
+           .Case("CC", TY_CXX)
+           .Case("cl", TY_CL)
+           .Case("cp", TY_CXX)
+           .Case("cu", TY_CUDA)
+           .Case("hh", TY_CXXHeader)
+           .Case("ll", TY_LLVM_IR)
+           .Case("hpp", TY_CXXHeader)
+           .Case("ads", TY_Ada)
+           .Case("adb", TY_Ada)
+           .Case("ast", TY_AST)
+           .Case("c++", TY_CXX)
+           .Case("C++", TY_CXX)
+           .Case("cxx", TY_CXX)
+           .Case("cpp", TY_CXX)
+           .Case("CPP", TY_CXX)
+           .Case("CXX", TY_CXX)
+           .Case("for", TY_PP_Fortran)
+           .Case("FOR", TY_PP_Fortran)
+           .Case("fpp", TY_Fortran)
+           .Case("FPP", TY_Fortran)
+           .Case("f90", TY_PP_Fortran)
+           .Case("f95", TY_PP_Fortran)
+           .Case("F90", TY_Fortran)
+           .Case("F95", TY_Fortran)
+           .Case("mii", TY_PP_ObjCXX)
+           .Default(TY_INVALID);
+}
+
+types::ID types::lookupTypeForTypeSpecifier(const char *Name) {
+  unsigned N = strlen(Name);
+
+  for (unsigned i=0; i<numTypes; ++i) {
+    types::ID Id = (types::ID) (i + 1);
+    if (canTypeBeUserSpecified(Id) &&
+        memcmp(Name, getInfo(Id).Name, N + 1) == 0)
+      return Id;
+  }
+
+  return TY_INVALID;
+}
+
+// FIXME: Why don't we just put this list in the defs file, eh.
+
+unsigned types::getNumCompilationPhases(ID Id) {
+  if (Id == TY_Object)
+    return 1;
+
+  unsigned N = 0;
+  if (getPreprocessedType(Id) != TY_INVALID)
+    N += 1;
+
+  if (onlyAssembleType(Id))
+    return N + 2; // assemble, link
+  if (onlyPrecompileType(Id))
+    return N + 1; // precompile
+
+  return N + 3; // compile, assemble, link
+}
+
+phases::ID types::getCompilationPhase(ID Id, unsigned N) {
+  assert(N < getNumCompilationPhases(Id) && "Invalid index.");
+
+  if (Id == TY_Object)
+    return phases::Link;
+
+  if (getPreprocessedType(Id) != TY_INVALID) {
+    if (N == 0)
+      return phases::Preprocess;
+    --N;
+  }
+
+  if (onlyAssembleType(Id))
+    return N == 0 ? phases::Assemble : phases::Link;
+
+  if (onlyPrecompileType(Id))
+    return phases::Precompile;
+
+  if (N == 0)
+    return phases::Compile;
+  if (N == 1)
+    return phases::Assemble;
+
+  return phases::Link;
+}
+
+ID types::lookupCXXTypeForCType(ID Id) {
+  switch (Id) {
+  default:
+    return Id;
+    
+  case types::TY_C:
+    return types::TY_CXX;
+  case types::TY_PP_C:
+    return types::TY_PP_CXX;
+  case types::TY_CHeader:
+    return types::TY_CXXHeader;
+  case types::TY_PP_CHeader:
+    return types::TY_PP_CXXHeader;
+  }
+}
diff --git a/clang/lib/Driver/WindowsToolChain.cpp b/clang/lib/Driver/WindowsToolChain.cpp
new file mode 100644
index 0000000..6827034
--- /dev/null
+++ b/clang/lib/Driver/WindowsToolChain.cpp
@@ -0,0 +1,368 @@
+//===--- ToolChains.cpp - ToolChain Implementations -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ToolChains.h"
+
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/Options.h"
+#include "clang/Basic/Version.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Path.h"
+
+// Include the necessary headers to interface with the Windows registry and
+// environment.
+#ifdef _MSC_VER
+  #define WIN32_LEAN_AND_MEAN
+  #define NOGDI
+  #define NOMINMAX
+  #include <Windows.h>
+#endif
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang;
+
+Windows::Windows(const Driver &D, const llvm::Triple& Triple)
+  : ToolChain(D, Triple) {
+}
+
+Tool &Windows::SelectTool(const Compilation &C, const JobAction &JA,
+                          const ActionList &Inputs) const {
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
+  bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
+                                             options::OPT_no_integrated_as,
+                                             IsIntegratedAssemblerDefault());
+
+  Tool *&T = Tools[Key];
+  if (!T) {
+    switch (Key) {
+    case Action::InputClass:
+    case Action::BindArchClass:
+    case Action::LipoJobClass:
+    case Action::DsymutilJobClass:
+    case Action::VerifyJobClass:
+      llvm_unreachable("Invalid tool kind.");
+    case Action::PreprocessJobClass:
+    case Action::PrecompileJobClass:
+    case Action::AnalyzeJobClass:
+    case Action::MigrateJobClass:
+    case Action::CompileJobClass:
+      T = new tools::Clang(*this); break;
+    case Action::AssembleJobClass:
+      if (!UseIntegratedAs && getTriple().getEnvironment() == llvm::Triple::MachO)
+        T = new tools::darwin::Assemble(*this);
+      else
+        T = new tools::ClangAs(*this);
+      break;
+    case Action::LinkJobClass:
+      T = new tools::visualstudio::Link(*this); break;
+    }
+  }
+
+  return *T;
+}
+
+bool Windows::IsIntegratedAssemblerDefault() const {
+  return true;
+}
+
+bool Windows::IsUnwindTablesDefault() const {
+  // FIXME: Gross; we should probably have some separate target
+  // definition, possibly even reusing the one in clang.
+  return getArchName() == "x86_64";
+}
+
+const char *Windows::GetDefaultRelocationModel() const {
+  return "static";
+}
+
+const char *Windows::GetForcedPicModel() const {
+  if (getArchName() == "x86_64")
+    return "pic";
+  return 0;
+}
+
+// FIXME: This probably should goto to some platform utils place.
+#ifdef _MSC_VER
+
+/// \brief Read registry string.
+/// This also supports a means to look for high-versioned keys by use
+/// of a $VERSION placeholder in the key path.
+/// $VERSION in the key path is a placeholder for the version number,
+/// causing the highest value path to be searched for and used.
+/// I.e. "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
+/// There can be additional characters in the component.  Only the numberic
+/// characters are compared.
+static bool getSystemRegistryString(const char *keyPath, const char *valueName,
+                                    char *value, size_t maxLength) {
+  HKEY hRootKey = NULL;
+  HKEY hKey = NULL;
+  const char* subKey = NULL;
+  DWORD valueType;
+  DWORD valueSize = maxLength - 1;
+  long lResult;
+  bool returnValue = false;
+
+  if (strncmp(keyPath, "HKEY_CLASSES_ROOT\\", 18) == 0) {
+    hRootKey = HKEY_CLASSES_ROOT;
+    subKey = keyPath + 18;
+  } else if (strncmp(keyPath, "HKEY_USERS\\", 11) == 0) {
+    hRootKey = HKEY_USERS;
+    subKey = keyPath + 11;
+  } else if (strncmp(keyPath, "HKEY_LOCAL_MACHINE\\", 19) == 0) {
+    hRootKey = HKEY_LOCAL_MACHINE;
+    subKey = keyPath + 19;
+  } else if (strncmp(keyPath, "HKEY_CURRENT_USER\\", 18) == 0) {
+    hRootKey = HKEY_CURRENT_USER;
+    subKey = keyPath + 18;
+  } else {
+    return false;
+  }
+
+  const char *placeHolder = strstr(subKey, "$VERSION");
+  char bestName[256];
+  bestName[0] = '\0';
+  // If we have a $VERSION placeholder, do the highest-version search.
+  if (placeHolder) {
+    const char *keyEnd = placeHolder - 1;
+    const char *nextKey = placeHolder;
+    // Find end of previous key.
+    while ((keyEnd > subKey) && (*keyEnd != '\\'))
+      keyEnd--;
+    // Find end of key containing $VERSION.
+    while (*nextKey && (*nextKey != '\\'))
+      nextKey++;
+    size_t partialKeyLength = keyEnd - subKey;
+    char partialKey[256];
+    if (partialKeyLength > sizeof(partialKey))
+      partialKeyLength = sizeof(partialKey);
+    strncpy(partialKey, subKey, partialKeyLength);
+    partialKey[partialKeyLength] = '\0';
+    HKEY hTopKey = NULL;
+    lResult = RegOpenKeyEx(hRootKey, partialKey, 0, KEY_READ, &hTopKey);
+    if (lResult == ERROR_SUCCESS) {
+      char keyName[256];
+      int bestIndex = -1;
+      double bestValue = 0.0;
+      DWORD index, size = sizeof(keyName) - 1;
+      for (index = 0; RegEnumKeyEx(hTopKey, index, keyName, &size, NULL,
+          NULL, NULL, NULL) == ERROR_SUCCESS; index++) {
+        const char *sp = keyName;
+        while (*sp && !isdigit(*sp))
+          sp++;
+        if (!*sp)
+          continue;
+        const char *ep = sp + 1;
+        while (*ep && (isdigit(*ep) || (*ep == '.')))
+          ep++;
+        char numBuf[32];
+        strncpy(numBuf, sp, sizeof(numBuf) - 1);
+        numBuf[sizeof(numBuf) - 1] = '\0';
+        double value = strtod(numBuf, NULL);
+        if (value > bestValue) {
+          bestIndex = (int)index;
+          bestValue = value;
+          strcpy(bestName, keyName);
+        }
+        size = sizeof(keyName) - 1;
+      }
+      // If we found the highest versioned key, open the key and get the value.
+      if (bestIndex != -1) {
+        // Append rest of key.
+        strncat(bestName, nextKey, sizeof(bestName) - 1);
+        bestName[sizeof(bestName) - 1] = '\0';
+        // Open the chosen key path remainder.
+        lResult = RegOpenKeyEx(hTopKey, bestName, 0, KEY_READ, &hKey);
+        if (lResult == ERROR_SUCCESS) {
+          lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
+            (LPBYTE)value, &valueSize);
+          if (lResult == ERROR_SUCCESS)
+            returnValue = true;
+          RegCloseKey(hKey);
+        }
+      }
+      RegCloseKey(hTopKey);
+    }
+  } else {
+    lResult = RegOpenKeyEx(hRootKey, subKey, 0, KEY_READ, &hKey);
+    if (lResult == ERROR_SUCCESS) {
+      lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
+        (LPBYTE)value, &valueSize);
+      if (lResult == ERROR_SUCCESS)
+        returnValue = true;
+      RegCloseKey(hKey);
+    }
+  }
+  return returnValue;
+}
+
+/// \brief Get Windows SDK installation directory.
+static bool getWindowsSDKDir(std::string &path) {
+  char windowsSDKInstallDir[256];
+  // Try the Windows registry.
+  bool hasSDKDir = getSystemRegistryString(
+   "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
+                                           "InstallationFolder",
+                                           windowsSDKInstallDir,
+                                           sizeof(windowsSDKInstallDir) - 1);
+    // If we have both vc80 and vc90, pick version we were compiled with.
+  if (hasSDKDir && windowsSDKInstallDir[0]) {
+    path = windowsSDKInstallDir;
+    return true;
+  }
+  return false;
+}
+
+  // Get Visual Studio installation directory.
+static bool getVisualStudioDir(std::string &path) {
+  // First check the environment variables that vsvars32.bat sets.
+  const char* vcinstalldir = getenv("VCINSTALLDIR");
+  if (vcinstalldir) {
+    char *p = const_cast<char *>(strstr(vcinstalldir, "\\VC"));
+    if (p)
+      *p = '\0';
+    path = vcinstalldir;
+    return true;
+  }
+
+  char vsIDEInstallDir[256];
+  char vsExpressIDEInstallDir[256];
+  // Then try the windows registry.
+  bool hasVCDir = getSystemRegistryString(
+    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION",
+    "InstallDir", vsIDEInstallDir, sizeof(vsIDEInstallDir) - 1);
+  bool hasVCExpressDir = getSystemRegistryString(
+    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VCExpress\\$VERSION",
+    "InstallDir", vsExpressIDEInstallDir, sizeof(vsExpressIDEInstallDir) - 1);
+    // If we have both vc80 and vc90, pick version we were compiled with.
+  if (hasVCDir && vsIDEInstallDir[0]) {
+    char *p = (char*)strstr(vsIDEInstallDir, "\\Common7\\IDE");
+    if (p)
+      *p = '\0';
+    path = vsIDEInstallDir;
+    return true;
+  }
+
+  if (hasVCExpressDir && vsExpressIDEInstallDir[0]) {
+    char *p = (char*)strstr(vsExpressIDEInstallDir, "\\Common7\\IDE");
+    if (p)
+      *p = '\0';
+    path = vsExpressIDEInstallDir;
+    return true;
+  }
+
+  // Try the environment.
+  const char *vs100comntools = getenv("VS100COMNTOOLS");
+  const char *vs90comntools = getenv("VS90COMNTOOLS");
+  const char *vs80comntools = getenv("VS80COMNTOOLS");
+  const char *vscomntools = NULL;
+
+  // Try to find the version that we were compiled with
+  if(false) {}
+  #if (_MSC_VER >= 1600)  // VC100
+  else if(vs100comntools) {
+    vscomntools = vs100comntools;
+  }
+  #elif (_MSC_VER == 1500) // VC80
+  else if(vs90comntools) {
+    vscomntools = vs90comntools;
+  }
+  #elif (_MSC_VER == 1400) // VC80
+  else if(vs80comntools) {
+    vscomntools = vs80comntools;
+  }
+  #endif
+  // Otherwise find any version we can
+  else if (vs100comntools)
+    vscomntools = vs100comntools;
+  else if (vs90comntools)
+    vscomntools = vs90comntools;
+  else if (vs80comntools)
+    vscomntools = vs80comntools;
+
+  if (vscomntools && *vscomntools) {
+    const char *p = strstr(vscomntools, "\\Common7\\Tools");
+    path = p ? std::string(vscomntools, p) : vscomntools;
+    return true;
+  }
+  return false;
+}
+
+#endif // _MSC_VER
+
+void Windows::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                        ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
+    return;
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    llvm::sys::Path P(getDriver().ResourceDir);
+    P.appendComponent("include");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+#ifdef _MSC_VER
+  // Honor %INCLUDE%. It should know essential search paths with vcvarsall.bat.
+  if (const char *cl_include_dir = getenv("INCLUDE")) {
+    SmallVector<StringRef, 8> Dirs;
+    StringRef(cl_include_dir).split(Dirs, ";");
+    int n = 0;
+    for (SmallVectorImpl<StringRef>::iterator I = Dirs.begin(), E = Dirs.end();
+         I != E; ++I) {
+      StringRef d = *I;
+      if (d.size() == 0)
+        continue;
+      ++n;
+      addSystemInclude(DriverArgs, CC1Args, d);
+    }
+    if (n) return;
+  }
+
+  std::string VSDir;
+  std::string WindowsSDKDir;
+
+  // When built with access to the proper Windows APIs, try to actually find
+  // the correct include paths first.
+  if (getVisualStudioDir(VSDir)) {
+    addSystemInclude(DriverArgs, CC1Args, VSDir + "\\VC\\include");
+    if (getWindowsSDKDir(WindowsSDKDir))
+      addSystemInclude(DriverArgs, CC1Args, WindowsSDKDir + "\\include");
+    else
+      addSystemInclude(DriverArgs, CC1Args,
+                       VSDir + "\\VC\\PlatformSDK\\Include");
+    return;
+  }
+#endif // _MSC_VER
+
+  // As a fallback, select default install paths.
+  const StringRef Paths[] = {
+    "C:/Program Files/Microsoft Visual Studio 10.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/PlatformSDK/Include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/PlatformSDK/Include"
+  };
+  addSystemIncludes(DriverArgs, CC1Args, Paths);
+}
+
+void Windows::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                           ArgStringList &CC1Args) const {
+  // FIXME: There should probably be logic here to find libc++ on Windows.
+}