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

7 files changed, 1307 insertions, 0 deletions

diff --git a/clang/tools/driver/CMakeLists.txt b/clang/tools/driver/CMakeLists.txt
new file mode 100644
index 0000000..ae49ac1
--- /dev/null
+++ b/clang/tools/driver/CMakeLists.txt
@@ -0,0 +1,63 @@
+set( LLVM_USED_LIBS
+  clangFrontendTool
+  clangAST
+  clangAnalysis
+  clangBasic
+  clangCodeGen
+  clangDriver
+  clangEdit
+  clangFrontend
+  clangLex
+  clangParse
+  clangEdit
+  clangARCMigrate
+  clangRewrite
+  clangSema
+  clangSerialization
+  clangStaticAnalyzerFrontend
+  clangStaticAnalyzerCheckers
+  clangStaticAnalyzerCore
+  )
+
+set( LLVM_LINK_COMPONENTS
+  ${LLVM_TARGETS_TO_BUILD}
+  asmparser
+  bitreader
+  bitwriter
+  codegen
+  instrumentation
+  ipo
+  linker
+  selectiondag
+  )
+
+add_clang_executable(clang
+  driver.cpp
+  cc1_main.cpp
+  cc1as_main.cpp
+  )
+
+set_target_properties(clang PROPERTIES VERSION ${CLANG_EXECUTABLE_VERSION})
+
+if(UNIX)
+  set(CLANGXX_LINK_OR_COPY create_symlink)
+# Create a relative symlink
+  set(clang_binary "clang${CMAKE_EXECUTABLE_SUFFIX}")
+else()
+  set(CLANGXX_LINK_OR_COPY copy)
+  set(clang_binary "${LLVM_BINARY_DIR}/bin/${CMAKE_CFG_INTDIR}/clang${CMAKE_EXECUTABLE_SUFFIX}")
+endif()
+
+# Create the clang++ symlink in the build directory.
+set(clang_pp "${LLVM_BINARY_DIR}/bin/${CMAKE_CFG_INTDIR}/clang++${CMAKE_EXECUTABLE_SUFFIX}")
+add_custom_command(TARGET clang POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E ${CLANGXX_LINK_OR_COPY} "${clang_binary}" "${clang_pp}")
+
+set_property(DIRECTORY APPEND
+  PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${clang_pp})
+
+install(TARGETS clang
+  RUNTIME DESTINATION bin)
+
+# Create the clang++ symlink at installation time.
+install(SCRIPT clang_symlink.cmake -DCMAKE_INSTALL_PREFIX=\"${CMAKE_INSTALL_PREFIX}\")
diff --git a/clang/tools/driver/Info.plist.in b/clang/tools/driver/Info.plist.in
new file mode 100644
index 0000000..c938fb0
--- /dev/null
+++ b/clang/tools/driver/Info.plist.in
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+        <key>CFBundleIdentifier</key>
+        <string>@TOOL_INFO_UTI@</string>
+        <key>CFBundleInfoDictionaryVersion</key>
+        <string>6.0</string>
+        <key>CFBundleName</key>
+        <string>@TOOL_INFO_NAME</string>
+	<key>CFBundleShortVersionString</key>
+	<string>@TOOL_INFO_VERSION@</string>
+        <key>CFBundleVersion</key>
+        <string>@TOOL_INFO_BUILD_VERSION@</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+</dict>
+</plist>
diff --git a/clang/tools/driver/Makefile b/clang/tools/driver/Makefile
new file mode 100644
index 0000000..270d4fd
--- /dev/null
+++ b/clang/tools/driver/Makefile
@@ -0,0 +1,69 @@
+##===- tools/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 := ../..
+
+TOOLNAME = clang
+TOOLALIAS = clang++
+
+# We don't currently expect production Clang builds to be interested in
+# plugins. This is important for startup performance.
+ifdef CLANG_IS_PRODUCTION
+TOOL_NO_EXPORTS := 1
+endif
+
+ifdef CLANG_ORDER_FILE
+TOOL_ORDER_FILE := $(CLANG_ORDER_FILE)
+endif
+
+# Include tool version information on OS X.
+TOOL_INFO_PLIST := Info.plist
+
+# Include this here so we can get the configuration of the targets that have
+# been configured for construction. We have to do this early so we can set up
+# LINK_COMPONENTS before including Makefile.rules
+include $(CLANG_LEVEL)/../../Makefile.config
+
+LINK_COMPONENTS := $(TARGETS_TO_BUILD) asmparser bitreader bitwriter codegen \
+                   instrumentation ipo linker selectiondag
+USEDLIBS = clangFrontendTool.a clangFrontend.a clangDriver.a \
+           clangSerialization.a clangCodeGen.a clangParse.a clangSema.a \
+           clangStaticAnalyzerFrontend.a clangStaticAnalyzerCheckers.a \
+           clangStaticAnalyzerCore.a \
+           clangAnalysis.a clangARCMigrate.a clangRewrite.a \
+           clangEdit.a clangAST.a clangLex.a clangBasic.a
+
+include $(CLANG_LEVEL)/Makefile
+
+# Set the tool version information values.
+ifeq ($(HOST_OS),Darwin)
+ifdef CLANG_VENDOR
+TOOL_INFO_NAME := $(CLANG_VENDOR) clang
+else
+TOOL_INFO_NAME := clang
+endif
+
+ifdef CLANG_VENDOR_UTI
+TOOL_INFO_UTI := $(CLANG_VENDOR_UTI)
+else
+TOOL_INFO_UTI := org.llvm.clang
+endif
+
+TOOL_INFO_VERSION := $(word 3,$(shell grep "CLANG_VERSION " \
+	$(PROJ_OBJ_DIR)/$(CLANG_LEVEL)/include/clang/Basic/Version.inc))
+ifdef LLVM_SUBMIT_VERSION
+TOOL_INFO_BUILD_VERSION := $(LLVM_SUBMIT_VERSION).$(LLVM_SUBMIT_SUBVERSION)
+else
+TOOL_INFO_BUILD_VERSION := 
+endif
+endif
+
+# Translate make variable to define when building a "production" clang.
+ifdef CLANG_IS_PRODUCTION
+CPP.Defines += -DCLANG_IS_PRODUCTION
+endif
diff --git a/clang/tools/driver/cc1_main.cpp b/clang/tools/driver/cc1_main.cpp
new file mode 100644
index 0000000..a211090
--- /dev/null
+++ b/clang/tools/driver/cc1_main.cpp
@@ -0,0 +1,189 @@
+//===-- cc1_main.cpp - Clang CC1 Compiler Frontend ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the entry point to the clang -cc1 functionality, which implements the
+// core compiler functionality along with a number of additional tools for
+// demonstration and testing purposes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/CC1Options.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/TextDiagnosticBuffer.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/FrontendTool/Utils.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/LinkAllPasses.h"
+#include <cstdio>
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Main driver
+//===----------------------------------------------------------------------===//
+
+static void LLVMErrorHandler(void *UserData, const std::string &Message) {
+  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
+
+  Diags.Report(diag::err_fe_error_backend) << Message;
+
+  // We cannot recover from llvm errors.
+  exit(1);
+}
+
+// FIXME: Define the need for this testing away.
+static int cc1_test(DiagnosticsEngine &Diags,
+                    const char **ArgBegin, const char **ArgEnd) {
+  using namespace clang::driver;
+
+  llvm::errs() << "cc1 argv:";
+  for (const char **i = ArgBegin; i != ArgEnd; ++i)
+    llvm::errs() << " \"" << *i << '"';
+  llvm::errs() << "\n";
+
+  // Parse the arguments.
+  OptTable *Opts = createCC1OptTable();
+  unsigned MissingArgIndex, MissingArgCount;
+  InputArgList *Args = Opts->ParseArgs(ArgBegin, ArgEnd,
+                                       MissingArgIndex, MissingArgCount);
+
+  // Check for missing argument error.
+  if (MissingArgCount)
+    Diags.Report(clang::diag::err_drv_missing_argument)
+      << Args->getArgString(MissingArgIndex) << MissingArgCount;
+
+  // Dump the parsed arguments.
+  llvm::errs() << "cc1 parsed options:\n";
+  for (ArgList::const_iterator it = Args->begin(), ie = Args->end();
+       it != ie; ++it)
+    (*it)->dump();
+
+  // Create a compiler invocation.
+  llvm::errs() << "cc1 creating invocation.\n";
+  CompilerInvocation Invocation;
+  if (!CompilerInvocation::CreateFromArgs(Invocation, ArgBegin, ArgEnd, Diags))
+    return 1;
+
+  // Convert the invocation back to argument strings.
+  std::vector<std::string> InvocationArgs;
+  Invocation.toArgs(InvocationArgs);
+
+  // Dump the converted arguments.
+  SmallVector<const char*, 32> Invocation2Args;
+  llvm::errs() << "invocation argv :";
+  for (unsigned i = 0, e = InvocationArgs.size(); i != e; ++i) {
+    Invocation2Args.push_back(InvocationArgs[i].c_str());
+    llvm::errs() << " \"" << InvocationArgs[i] << '"';
+  }
+  llvm::errs() << "\n";
+
+  // Convert those arguments to another invocation, and check that we got the
+  // same thing.
+  CompilerInvocation Invocation2;
+  if (!CompilerInvocation::CreateFromArgs(Invocation2, Invocation2Args.begin(),
+                                          Invocation2Args.end(), Diags))
+    return 1;
+
+  // FIXME: Implement CompilerInvocation comparison.
+  if (true) {
+    //llvm::errs() << "warning: Invocations differ!\n";
+
+    std::vector<std::string> Invocation2Args;
+    Invocation2.toArgs(Invocation2Args);
+    llvm::errs() << "invocation2 argv:";
+    for (unsigned i = 0, e = Invocation2Args.size(); i != e; ++i)
+      llvm::errs() << " \"" << Invocation2Args[i] << '"';
+    llvm::errs() << "\n";
+  }
+
+  return 0;
+}
+
+int cc1_main(const char **ArgBegin, const char **ArgEnd,
+             const char *Argv0, void *MainAddr) {
+  OwningPtr<CompilerInstance> Clang(new CompilerInstance());
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+
+  // Run clang -cc1 test.
+  if (ArgBegin != ArgEnd && StringRef(ArgBegin[0]) == "-cc1test") {
+    DiagnosticsEngine Diags(DiagID, new TextDiagnosticPrinter(llvm::errs(), 
+                                                       DiagnosticOptions()));
+    return cc1_test(Diags, ArgBegin + 1, ArgEnd);
+  }
+
+  // Initialize targets first, so that --version shows registered targets.
+  llvm::InitializeAllTargets();
+  llvm::InitializeAllTargetMCs();
+  llvm::InitializeAllAsmPrinters();
+  llvm::InitializeAllAsmParsers();
+
+  // Buffer diagnostics from argument parsing so that we can output them using a
+  // well formed diagnostic object.
+  TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
+  DiagnosticsEngine Diags(DiagID, DiagsBuffer);
+  bool Success;
+  Success = CompilerInvocation::CreateFromArgs(Clang->getInvocation(),
+                                               ArgBegin, ArgEnd, Diags);
+
+  // Infer the builtin include path if unspecified.
+  if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
+      Clang->getHeaderSearchOpts().ResourceDir.empty())
+    Clang->getHeaderSearchOpts().ResourceDir =
+      CompilerInvocation::GetResourcesPath(Argv0, MainAddr);
+
+  // Create the actual diagnostics engine.
+  Clang->createDiagnostics(ArgEnd - ArgBegin, const_cast<char**>(ArgBegin));
+  if (!Clang->hasDiagnostics())
+    return 1;
+
+  // Set an error handler, so that any LLVM backend diagnostics go through our
+  // error handler.
+  llvm::install_fatal_error_handler(LLVMErrorHandler,
+                                  static_cast<void*>(&Clang->getDiagnostics()));
+
+  DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics());
+  if (!Success)
+    return 1;
+
+  // Execute the frontend actions.
+  Success = ExecuteCompilerInvocation(Clang.get());
+
+  // If any timers were active but haven't been destroyed yet, print their
+  // results now.  This happens in -disable-free mode.
+  llvm::TimerGroup::printAll(llvm::errs());
+
+  // Our error handler depends on the Diagnostics object, which we're
+  // potentially about to delete. Uninstall the handler now so that any
+  // later errors use the default handling behavior instead.
+  llvm::remove_fatal_error_handler();
+
+  // When running with -disable-free, don't do any destruction or shutdown.
+  if (Clang->getFrontendOpts().DisableFree) {
+    if (llvm::AreStatisticsEnabled() || Clang->getFrontendOpts().ShowStats)
+      llvm::PrintStatistics();
+    Clang.take();
+    return !Success;
+  }
+
+  // Managed static deconstruction. Useful for making things like
+  // -time-passes usable.
+  llvm::llvm_shutdown();
+
+  return !Success;
+}
diff --git a/clang/tools/driver/cc1as_main.cpp b/clang/tools/driver/cc1as_main.cpp
new file mode 100644
index 0000000..508d6da
--- /dev/null
+++ b/clang/tools/driver/cc1as_main.cpp
@@ -0,0 +1,451 @@
+//===-- cc1as_main.cpp - Clang Assembler  ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the entry point to the clang -cc1as functionality, which implements
+// the direct interface to the LLVM MC based assembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/CC1AsOptions.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Driver/Options.h"
+#include "clang/Frontend/DiagnosticOptions.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCTargetAsmParser.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/system_error.h"
+#include "llvm/Target/TargetData.h"
+using namespace clang;
+using namespace clang::driver;
+using namespace llvm;
+
+namespace {
+
+/// \brief Helper class for representing a single invocation of the assembler.
+struct AssemblerInvocation {
+  /// @name Target Options
+  /// @{
+
+  /// The name of the target triple to assemble for.
+  std::string Triple;
+
+  /// If given, the name of the target CPU to determine which instructions
+  /// are legal.
+  std::string CPU;
+
+  /// The list of target specific features to enable or disable -- this should
+  /// be a list of strings starting with '+' or '-'.
+  std::vector<std::string> Features;
+
+  /// @}
+  /// @name Language Options
+  /// @{
+
+  std::vector<std::string> IncludePaths;
+  unsigned NoInitialTextSection : 1;
+  unsigned SaveTemporaryLabels : 1;
+  unsigned GenDwarfForAssembly : 1;
+  std::string DwarfDebugFlags;
+
+  /// @}
+  /// @name Frontend Options
+  /// @{
+
+  std::string InputFile;
+  std::vector<std::string> LLVMArgs;
+  std::string OutputPath;
+  enum FileType {
+    FT_Asm,  ///< Assembly (.s) output, transliterate mode.
+    FT_Null, ///< No output, for timing purposes.
+    FT_Obj   ///< Object file output.
+  };
+  FileType OutputType;
+  unsigned ShowHelp : 1;
+  unsigned ShowVersion : 1;
+
+  /// @}
+  /// @name Transliterate Options
+  /// @{
+
+  unsigned OutputAsmVariant;
+  unsigned ShowEncoding : 1;
+  unsigned ShowInst : 1;
+
+  /// @}
+  /// @name Assembler Options
+  /// @{
+
+  unsigned RelaxAll : 1;
+  unsigned NoExecStack : 1;
+
+  /// @}
+
+public:
+  AssemblerInvocation() {
+    Triple = "";
+    NoInitialTextSection = 0;
+    InputFile = "-";
+    OutputPath = "-";
+    OutputType = FT_Asm;
+    OutputAsmVariant = 0;
+    ShowInst = 0;
+    ShowEncoding = 0;
+    RelaxAll = 0;
+    NoExecStack = 0;
+  }
+
+  static bool CreateFromArgs(AssemblerInvocation &Res, const char **ArgBegin,
+                             const char **ArgEnd, DiagnosticsEngine &Diags);
+};
+
+}
+
+bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
+                                         const char **ArgBegin,
+                                         const char **ArgEnd,
+                                         DiagnosticsEngine &Diags) {
+  using namespace clang::driver::cc1asoptions;
+  bool Success = true;
+
+  // Parse the arguments.
+  OwningPtr<OptTable> OptTbl(createCC1AsOptTable());
+  unsigned MissingArgIndex, MissingArgCount;
+  OwningPtr<InputArgList> Args(
+    OptTbl->ParseArgs(ArgBegin, ArgEnd,MissingArgIndex, MissingArgCount));
+
+  // Check for missing argument error.
+  if (MissingArgCount) {
+    Diags.Report(diag::err_drv_missing_argument)
+      << Args->getArgString(MissingArgIndex) << MissingArgCount;
+    Success = false;
+  }
+
+  // Issue errors on unknown arguments.
+  for (arg_iterator it = Args->filtered_begin(cc1asoptions::OPT_UNKNOWN),
+         ie = Args->filtered_end(); it != ie; ++it) {
+    Diags.Report(diag::err_drv_unknown_argument) << (*it) ->getAsString(*Args);
+    Success = false;
+  }
+
+  // Construct the invocation.
+
+  // Target Options
+  Opts.Triple = llvm::Triple::normalize(Args->getLastArgValue(OPT_triple));
+  Opts.CPU = Args->getLastArgValue(OPT_target_cpu);
+  Opts.Features = Args->getAllArgValues(OPT_target_feature);
+
+  // Use the default target triple if unspecified.
+  if (Opts.Triple.empty())
+    Opts.Triple = llvm::sys::getDefaultTargetTriple();
+
+  // Language Options
+  Opts.IncludePaths = Args->getAllArgValues(OPT_I);
+  Opts.NoInitialTextSection = Args->hasArg(OPT_n);
+  Opts.SaveTemporaryLabels = Args->hasArg(OPT_L);
+  Opts.GenDwarfForAssembly = Args->hasArg(OPT_g);
+  Opts.DwarfDebugFlags = Args->getLastArgValue(OPT_dwarf_debug_flags);
+
+  // Frontend Options
+  if (Args->hasArg(OPT_INPUT)) {
+    bool First = true;
+    for (arg_iterator it = Args->filtered_begin(OPT_INPUT),
+           ie = Args->filtered_end(); it != ie; ++it, First=false) {
+      const Arg *A = it;
+      if (First)
+        Opts.InputFile = A->getValue(*Args);
+      else {
+        Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(*Args);
+        Success = false;
+      }
+    }
+  }
+  Opts.LLVMArgs = Args->getAllArgValues(OPT_mllvm);
+  if (Args->hasArg(OPT_fatal_warnings))
+    Opts.LLVMArgs.push_back("-fatal-assembler-warnings");
+  Opts.OutputPath = Args->getLastArgValue(OPT_o);
+  if (Arg *A = Args->getLastArg(OPT_filetype)) {
+    StringRef Name = A->getValue(*Args);
+    unsigned OutputType = StringSwitch<unsigned>(Name)
+      .Case("asm", FT_Asm)
+      .Case("null", FT_Null)
+      .Case("obj", FT_Obj)
+      .Default(~0U);
+    if (OutputType == ~0U) {
+      Diags.Report(diag::err_drv_invalid_value)
+        << A->getAsString(*Args) << Name;
+      Success = false;
+    } else
+      Opts.OutputType = FileType(OutputType);
+  }
+  Opts.ShowHelp = Args->hasArg(OPT_help);
+  Opts.ShowVersion = Args->hasArg(OPT_version);
+
+  // Transliterate Options
+  Opts.OutputAsmVariant = Args->getLastArgIntValue(OPT_output_asm_variant,
+                                                   0, Diags);
+  Opts.ShowEncoding = Args->hasArg(OPT_show_encoding);
+  Opts.ShowInst = Args->hasArg(OPT_show_inst);
+
+  // Assemble Options
+  Opts.RelaxAll = Args->hasArg(OPT_relax_all);
+  Opts.NoExecStack =  Args->hasArg(OPT_no_exec_stack);
+
+  return Success;
+}
+
+static formatted_raw_ostream *GetOutputStream(AssemblerInvocation &Opts,
+                                              DiagnosticsEngine &Diags,
+                                              bool Binary) {
+  if (Opts.OutputPath.empty())
+    Opts.OutputPath = "-";
+
+  // Make sure that the Out file gets unlinked from the disk if we get a
+  // SIGINT.
+  if (Opts.OutputPath != "-")
+    sys::RemoveFileOnSignal(sys::Path(Opts.OutputPath));
+
+  std::string Error;
+  raw_fd_ostream *Out =
+    new raw_fd_ostream(Opts.OutputPath.c_str(), Error,
+                       (Binary ? raw_fd_ostream::F_Binary : 0));
+  if (!Error.empty()) {
+    Diags.Report(diag::err_fe_unable_to_open_output)
+      << Opts.OutputPath << Error;
+    return 0;
+  }
+
+  return new formatted_raw_ostream(*Out, formatted_raw_ostream::DELETE_STREAM);
+}
+
+static bool ExecuteAssembler(AssemblerInvocation &Opts,
+                             DiagnosticsEngine &Diags) {
+  // Get the target specific parser.
+  std::string Error;
+  const Target *TheTarget(TargetRegistry::lookupTarget(Opts.Triple, Error));
+  if (!TheTarget) {
+    Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
+    return false;
+  }
+
+  OwningPtr<MemoryBuffer> BufferPtr;
+  if (error_code ec = MemoryBuffer::getFileOrSTDIN(Opts.InputFile, BufferPtr)) {
+    Error = ec.message();
+    Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
+    return false;
+  }
+  MemoryBuffer *Buffer = BufferPtr.take();
+
+  SourceMgr SrcMgr;
+
+  // Tell SrcMgr about this buffer, which is what the parser will pick up.
+  SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
+
+  // Record the location of the include directories so that the lexer can find
+  // it later.
+  SrcMgr.setIncludeDirs(Opts.IncludePaths);
+
+  OwningPtr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(Opts.Triple));
+  assert(MAI && "Unable to create target asm info!");
+
+  OwningPtr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
+  assert(MRI && "Unable to create target register info!");
+
+  bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
+  formatted_raw_ostream *Out = GetOutputStream(Opts, Diags, IsBinary);
+  if (!Out)
+    return false;
+
+  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
+  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
+  OwningPtr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
+  MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr);
+  // FIXME: Assembler behavior can change with -static.
+  MOFI->InitMCObjectFileInfo(Opts.Triple,
+                             Reloc::Default, CodeModel::Default, Ctx);
+  if (Opts.SaveTemporaryLabels)
+    Ctx.setAllowTemporaryLabels(false);
+  if (Opts.GenDwarfForAssembly)
+    Ctx.setGenDwarfForAssembly(true);
+  if (!Opts.DwarfDebugFlags.empty())
+    Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
+
+  // Build up the feature string from the target feature list.
+  std::string FS;
+  if (!Opts.Features.empty()) {
+    FS = Opts.Features[0];
+    for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
+      FS += "," + Opts.Features[i];
+  }
+
+  OwningPtr<MCStreamer> Str;
+
+  OwningPtr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
+  OwningPtr<MCSubtargetInfo>
+    STI(TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
+
+  // FIXME: There is a bit of code duplication with addPassesToEmitFile.
+  if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
+    MCInstPrinter *IP =
+      TheTarget->createMCInstPrinter(Opts.OutputAsmVariant, *MAI, *MCII, *MRI,
+                                     *STI);
+    MCCodeEmitter *CE = 0;
+    MCAsmBackend *MAB = 0;
+    if (Opts.ShowEncoding) {
+      CE = TheTarget->createMCCodeEmitter(*MCII, *STI, Ctx);
+      MAB = TheTarget->createMCAsmBackend(Opts.Triple);
+    }
+    Str.reset(TheTarget->createAsmStreamer(Ctx, *Out, /*asmverbose*/true,
+                                           /*useLoc*/ true,
+                                           /*useCFI*/ true,
+                                           /*useDwarfDirectory*/ true,
+                                           IP, CE, MAB,
+                                           Opts.ShowInst));
+  } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
+    Str.reset(createNullStreamer(Ctx));
+  } else {
+    assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
+           "Invalid file type!");
+    MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *STI, Ctx);
+    MCAsmBackend *MAB = TheTarget->createMCAsmBackend(Opts.Triple);
+    Str.reset(TheTarget->createMCObjectStreamer(Opts.Triple, Ctx, *MAB, *Out,
+                                                CE, Opts.RelaxAll,
+                                                Opts.NoExecStack));
+    Str.get()->InitSections();
+  }
+
+  OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr, Ctx,
+                                                  *Str.get(), *MAI));
+  OwningPtr<MCTargetAsmParser> TAP(TheTarget->createMCAsmParser(*STI, *Parser));
+  if (!TAP) {
+    Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
+    return false;
+  }
+
+  Parser->setTargetParser(*TAP.get());
+
+  bool Success = !Parser->Run(Opts.NoInitialTextSection);
+
+  // Close the output.
+  delete Out;
+
+  // Delete output on errors.
+  if (!Success && Opts.OutputPath != "-")
+    sys::Path(Opts.OutputPath).eraseFromDisk();
+
+  return Success;
+}
+
+static void LLVMErrorHandler(void *UserData, const std::string &Message) {
+  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
+
+  Diags.Report(diag::err_fe_error_backend) << Message;
+
+  // We cannot recover from llvm errors.
+  exit(1);
+}
+
+int cc1as_main(const char **ArgBegin, const char **ArgEnd,
+               const char *Argv0, void *MainAddr) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(ArgEnd - ArgBegin, ArgBegin);
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+  // Initialize targets and assembly printers/parsers.
+  InitializeAllTargetInfos();
+  InitializeAllTargetMCs();
+  InitializeAllAsmParsers();
+
+  // Construct our diagnostic client.
+  TextDiagnosticPrinter *DiagClient
+    = new TextDiagnosticPrinter(errs(), DiagnosticOptions());
+  DiagClient->setPrefix("clang -cc1as");
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  DiagnosticsEngine Diags(DiagID, DiagClient);
+
+  // Set an error handler, so that any LLVM backend diagnostics go through our
+  // error handler.
+  ScopedFatalErrorHandler FatalErrorHandler
+    (LLVMErrorHandler, static_cast<void*>(&Diags));
+
+  // Parse the arguments.
+  AssemblerInvocation Asm;
+  if (!AssemblerInvocation::CreateFromArgs(Asm, ArgBegin, ArgEnd, Diags))
+    return 1;
+
+  // Honor -help.
+  if (Asm.ShowHelp) {
+    OwningPtr<driver::OptTable> Opts(driver::createCC1AsOptTable());
+    Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler");
+    return 0;
+  }
+
+  // Honor -version.
+  //
+  // FIXME: Use a better -version message?
+  if (Asm.ShowVersion) {
+    llvm::cl::PrintVersionMessage();
+    return 0;
+  }
+
+  // Honor -mllvm.
+  //
+  // FIXME: Remove this, one day.
+  if (!Asm.LLVMArgs.empty()) {
+    unsigned NumArgs = Asm.LLVMArgs.size();
+    const char **Args = new const char*[NumArgs + 2];
+    Args[0] = "clang (LLVM option parsing)";
+    for (unsigned i = 0; i != NumArgs; ++i)
+      Args[i + 1] = Asm.LLVMArgs[i].c_str();
+    Args[NumArgs + 1] = 0;
+    llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
+  }
+
+  // Execute the invocation, unless there were parsing errors.
+  bool Success = false;
+  if (!Diags.hasErrorOccurred())
+    Success = ExecuteAssembler(Asm, Diags);
+
+  // If any timers were active but haven't been destroyed yet, print their
+  // results now.
+  TimerGroup::printAll(errs());
+
+  return !Success;
+}
diff --git a/clang/tools/driver/clang_symlink.cmake b/clang/tools/driver/clang_symlink.cmake
new file mode 100644
index 0000000..c7341cb
--- /dev/null
+++ b/clang/tools/driver/clang_symlink.cmake
@@ -0,0 +1,27 @@
+# We need to execute this script at installation time because the
+# DESTDIR environment variable may be unset at configuration time.
+# See PR8397.
+
+if(UNIX)
+  set(CLANGXX_LINK_OR_COPY create_symlink)
+  set(CLANGXX_DESTDIR $ENV{DESTDIR})
+else()
+  set(CLANGXX_LINK_OR_COPY copy)
+endif()
+
+# CMAKE_EXECUTABLE_SUFFIX is undefined on cmake scripts. See PR9286.
+if( WIN32 )
+  set(EXECUTABLE_SUFFIX ".exe")
+else()
+  set(EXECUTABLE_SUFFIX "")
+endif()
+
+set(bindir "${CLANGXX_DESTDIR}${CMAKE_INSTALL_PREFIX}/bin/")
+set(clang "clang${EXECUTABLE_SUFFIX}")
+set(clangxx "clang++${EXECUTABLE_SUFFIX}")
+
+message("Creating clang++ executable based on ${clang}")
+
+execute_process(
+  COMMAND "${CMAKE_COMMAND}" -E ${CLANGXX_LINK_OR_COPY} "${clang}" "${clangxx}"
+  WORKING_DIRECTORY "${bindir}")
diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
new file mode 100644
index 0000000..8c05fff
--- /dev/null
+++ b/clang/tools/driver/driver.cpp
@@ -0,0 +1,490 @@
+//===-- 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.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the entry point to the clang driver; it is a thin wrapper
+// for functionality in the Driver clang library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/CC1Options.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/OptTable.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Frontend/DiagnosticOptions.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Frontend/Utils.h"
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Regex.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/system_error.h"
+#include <cctype>
+using namespace clang;
+using namespace clang::driver;
+
+llvm::sys::Path GetExecutablePath(const char *Argv0, bool CanonicalPrefixes) {
+  if (!CanonicalPrefixes)
+    return llvm::sys::Path(Argv0);
+
+  // This just needs to be some symbol in the binary; C++ doesn't
+  // allow taking the address of ::main however.
+  void *P = (void*) (intptr_t) GetExecutablePath;
+  return llvm::sys::Path::GetMainExecutable(Argv0, P);
+}
+
+static const char *SaveStringInSet(std::set<std::string> &SavedStrings,
+                                   StringRef S) {
+  return SavedStrings.insert(S).first->c_str();
+}
+
+/// ApplyQAOverride - Apply a list of edits to the input argument lists.
+///
+/// The input string is a space separate list of edits to perform,
+/// they are applied in order to the input argument lists. Edits
+/// should be one of the following forms:
+///
+///  '#': Silence information about the changes to the command line arguments.
+///
+///  '^': Add FOO as a new argument at the beginning of the command line.
+///
+///  '+': Add FOO as a new argument at the end of the command line.
+///
+///  's/XXX/YYY/': Substitute the regular expression XXX with YYY in the command
+///  line.
+///
+///  'xOPTION': Removes all instances of the literal argument OPTION.
+///
+///  'XOPTION': Removes all instances of the literal argument OPTION,
+///  and the following argument.
+///
+///  'Ox': Removes all flags matching 'O' or 'O[sz0-9]' and adds 'Ox'
+///  at the end of the command line.
+///
+/// \param OS - The stream to write edit information to.
+/// \param Args - The vector of command line arguments.
+/// \param Edit - The override command to perform.
+/// \param SavedStrings - Set to use for storing string representations.
+static void ApplyOneQAOverride(raw_ostream &OS,
+                               SmallVectorImpl<const char*> &Args,
+                               StringRef Edit,
+                               std::set<std::string> &SavedStrings) {
+  // This does not need to be efficient.
+
+  if (Edit[0] == '^') {
+    const char *Str =
+      SaveStringInSet(SavedStrings, Edit.substr(1));
+    OS << "### Adding argument " << Str << " at beginning\n";
+    Args.insert(Args.begin() + 1, Str);
+  } else if (Edit[0] == '+') {
+    const char *Str =
+      SaveStringInSet(SavedStrings, Edit.substr(1));
+    OS << "### Adding argument " << Str << " at end\n";
+    Args.push_back(Str);
+  } else if (Edit[0] == 's' && Edit[1] == '/' && Edit.endswith("/") &&
+             Edit.slice(2, Edit.size()-1).find('/') != StringRef::npos) {
+    StringRef MatchPattern = Edit.substr(2).split('/').first;
+    StringRef ReplPattern = Edit.substr(2).split('/').second;
+    ReplPattern = ReplPattern.slice(0, ReplPattern.size()-1);
+
+    for (unsigned i = 1, e = Args.size(); i != e; ++i) {
+      std::string Repl = llvm::Regex(MatchPattern).sub(ReplPattern, Args[i]);
+
+      if (Repl != Args[i]) {
+        OS << "### Replacing '" << Args[i] << "' with '" << Repl << "'\n";
+        Args[i] = SaveStringInSet(SavedStrings, Repl);
+      }
+    }
+  } else if (Edit[0] == 'x' || Edit[0] == 'X') {
+    std::string Option = Edit.substr(1, std::string::npos);
+    for (unsigned i = 1; i < Args.size();) {
+      if (Option == Args[i]) {
+        OS << "### Deleting argument " << Args[i] << '\n';
+        Args.erase(Args.begin() + i);
+        if (Edit[0] == 'X') {
+          if (i < Args.size()) {
+            OS << "### Deleting argument " << Args[i] << '\n';
+            Args.erase(Args.begin() + i);
+          } else
+            OS << "### Invalid X edit, end of command line!\n";
+        }
+      } else
+        ++i;
+    }
+  } else if (Edit[0] == 'O') {
+    for (unsigned i = 1; i < Args.size();) {
+      const char *A = Args[i];
+      if (A[0] == '-' && A[1] == 'O' &&
+          (A[2] == '\0' ||
+           (A[3] == '\0' && (A[2] == 's' || A[2] == 'z' ||
+                             ('0' <= A[2] && A[2] <= '9'))))) {
+        OS << "### Deleting argument " << Args[i] << '\n';
+        Args.erase(Args.begin() + i);
+      } else
+        ++i;
+    }
+    OS << "### Adding argument " << Edit << " at end\n";
+    Args.push_back(SaveStringInSet(SavedStrings, '-' + Edit.str()));
+  } else {
+    OS << "### Unrecognized edit: " << Edit << "\n";
+  }
+}
+
+/// ApplyQAOverride - Apply a comma separate list of edits to the
+/// input argument lists. See ApplyOneQAOverride.
+static void ApplyQAOverride(SmallVectorImpl<const char*> &Args,
+                            const char *OverrideStr,
+                            std::set<std::string> &SavedStrings) {
+  raw_ostream *OS = &llvm::errs();
+
+  if (OverrideStr[0] == '#') {
+    ++OverrideStr;
+    OS = &llvm::nulls();
+  }
+
+  *OS << "### QA_OVERRIDE_GCC3_OPTIONS: " << OverrideStr << "\n";
+
+  // This does not need to be efficient.
+
+  const char *S = OverrideStr;
+  while (*S) {
+    const char *End = ::strchr(S, ' ');
+    if (!End)
+      End = S + strlen(S);
+    if (End != S)
+      ApplyOneQAOverride(*OS, Args, std::string(S, End), SavedStrings);
+    S = End;
+    if (*S != '\0')
+      ++S;
+  }
+}
+
+extern int cc1_main(const char **ArgBegin, const char **ArgEnd,
+                    const char *Argv0, void *MainAddr);
+extern int cc1as_main(const char **ArgBegin, const char **ArgEnd,
+                      const char *Argv0, void *MainAddr);
+
+static void ExpandArgsFromBuf(const char *Arg,
+                              SmallVectorImpl<const char*> &ArgVector,
+                              std::set<std::string> &SavedStrings) {
+  const char *FName = Arg + 1;
+  OwningPtr<llvm::MemoryBuffer> MemBuf;
+  if (llvm::MemoryBuffer::getFile(FName, MemBuf)) {
+    ArgVector.push_back(SaveStringInSet(SavedStrings, Arg));
+    return;
+  }
+
+  const char *Buf = MemBuf->getBufferStart();
+  char InQuote = ' ';
+  std::string CurArg;
+
+  for (const char *P = Buf; ; ++P) {
+    if (*P == '\0' || (isspace(*P) && InQuote == ' ')) {
+      if (!CurArg.empty()) {
+
+        if (CurArg[0] != '@') {
+          ArgVector.push_back(SaveStringInSet(SavedStrings, CurArg));
+        } else {
+          ExpandArgsFromBuf(CurArg.c_str(), ArgVector, SavedStrings);
+        }
+
+        CurArg = "";
+      }
+      if (*P == '\0')
+        break;
+      else
+        continue;
+    }
+
+    if (isspace(*P)) {
+      if (InQuote != ' ')
+        CurArg.push_back(*P);
+      continue;
+    }
+
+    if (*P == '"' || *P == '\'') {
+      if (InQuote == *P)
+        InQuote = ' ';
+      else if (InQuote == ' ')
+        InQuote = *P;
+      else
+        CurArg.push_back(*P);
+      continue;
+    }
+
+    if (*P == '\\') {
+      ++P;
+      if (*P != '\0')
+        CurArg.push_back(*P);
+      continue;
+    }
+    CurArg.push_back(*P);
+  }
+}
+
+static void ExpandArgv(int argc, const char **argv,
+                       SmallVectorImpl<const char*> &ArgVector,
+                       std::set<std::string> &SavedStrings) {
+  for (int i = 0; i < argc; ++i) {
+    const char *Arg = argv[i];
+    if (Arg[0] != '@') {
+      ArgVector.push_back(SaveStringInSet(SavedStrings, std::string(Arg)));
+      continue;
+    }
+
+    ExpandArgsFromBuf(Arg, ArgVector, SavedStrings);
+  }
+}
+
+static void ParseProgName(SmallVectorImpl<const char *> &ArgVector,
+                          std::set<std::string> &SavedStrings,
+                          Driver &TheDriver)
+{
+  // Try to infer frontend type and default target from the program name.
+
+  // suffixes[] contains the list of known driver suffixes.
+  // Suffixes are compared against the program name in order.
+  // If there is a match, the frontend type is updated as necessary (CPP/C++).
+  // If there is no match, a second round is done after stripping the last
+  // hyphen and everything following it. This allows using something like
+  // "clang++-2.9".
+
+  // If there is a match in either the first or second round,
+  // the function tries to identify a target as prefix. E.g.
+  // "x86_64-linux-clang" as interpreted as suffix "clang" with
+  // target prefix "x86_64-linux". If such a target prefix is found,
+  // is gets added via -target as implicit first argument.
+  static const struct {
+    const char *Suffix;
+    bool IsCXX;
+    bool IsCPP;
+  } suffixes [] = {
+    { "clang", false, false },
+    { "clang++", true, false },
+    { "clang-c++", true, false },
+    { "clang-cc", false, false },
+    { "clang-cpp", false, true },
+    { "clang-g++", true, false },
+    { "clang-gcc", false, false },
+    { "cc", false, false },
+    { "cpp", false, true },
+    { "++", true, false },
+  };
+  std::string ProgName(llvm::sys::path::stem(ArgVector[0]));
+  StringRef ProgNameRef(ProgName);
+  StringRef Prefix;
+
+  for (int Components = 2; Components; --Components) {
+    bool FoundMatch = false;
+    size_t i;
+
+    for (i = 0; i < sizeof(suffixes) / sizeof(suffixes[0]); ++i) {
+      if (ProgNameRef.endswith(suffixes[i].Suffix)) {
+        FoundMatch = true;
+        if (suffixes[i].IsCXX)
+          TheDriver.CCCIsCXX = true;
+        if (suffixes[i].IsCPP)
+          TheDriver.CCCIsCPP = true;
+        break;
+      }
+    }
+
+    if (FoundMatch) {
+      StringRef::size_type LastComponent = ProgNameRef.rfind('-',
+        ProgNameRef.size() - strlen(suffixes[i].Suffix));
+      if (LastComponent != StringRef::npos)
+        Prefix = ProgNameRef.slice(0, LastComponent);
+      break;
+    }
+
+    StringRef::size_type LastComponent = ProgNameRef.rfind('-');
+    if (LastComponent == StringRef::npos)
+      break;
+    ProgNameRef = ProgNameRef.slice(0, LastComponent);
+  }
+
+  if (Prefix.empty())
+    return;
+
+  std::string IgnoredError;
+  if (llvm::TargetRegistry::lookupTarget(Prefix, IgnoredError)) {
+    SmallVectorImpl<const char *>::iterator it = ArgVector.begin();
+    if (it != ArgVector.end())
+      ++it;
+    ArgVector.insert(it, SaveStringInSet(SavedStrings, Prefix));
+    ArgVector.insert(it,
+      SaveStringInSet(SavedStrings, std::string("-target")));
+  }
+}
+
+int main(int argc_, const char **argv_) {
+  llvm::sys::PrintStackTraceOnErrorSignal();
+  llvm::PrettyStackTraceProgram X(argc_, argv_);
+
+  std::set<std::string> SavedStrings;
+  SmallVector<const char*, 256> argv;
+
+  ExpandArgv(argc_, argv_, argv, SavedStrings);
+
+  // Handle -cc1 integrated tools.
+  if (argv.size() > 1 && StringRef(argv[1]).startswith("-cc1")) {
+    StringRef Tool = argv[1] + 4;
+
+    if (Tool == "")
+      return cc1_main(argv.data()+2, argv.data()+argv.size(), argv[0],
+                      (void*) (intptr_t) GetExecutablePath);
+    if (Tool == "as")
+      return cc1as_main(argv.data()+2, argv.data()+argv.size(), argv[0],
+                      (void*) (intptr_t) GetExecutablePath);
+
+    // Reject unknown tools.
+    llvm::errs() << "error: unknown integrated tool '" << Tool << "'\n";
+    return 1;
+  }
+
+  bool CanonicalPrefixes = true;
+  for (int i = 1, size = argv.size(); i < size; ++i) {
+    if (StringRef(argv[i]) == "-no-canonical-prefixes") {
+      CanonicalPrefixes = false;
+      break;
+    }
+  }
+
+  llvm::sys::Path Path = GetExecutablePath(argv[0], CanonicalPrefixes);
+
+  DiagnosticOptions DiagOpts;
+  {
+    // Note that ParseDiagnosticArgs() uses the cc1 option table.
+    OwningPtr<OptTable> CC1Opts(createCC1OptTable());
+    unsigned MissingArgIndex, MissingArgCount;
+    OwningPtr<InputArgList> Args(CC1Opts->ParseArgs(argv.begin()+1, argv.end(),
+                                            MissingArgIndex, MissingArgCount));
+    // We ignore MissingArgCount and the return value of ParseDiagnosticArgs.
+    // Any errors that would be diagnosed here will also be diagnosed later,
+    // when the DiagnosticsEngine actually exists.
+    (void) ParseDiagnosticArgs(DiagOpts, *Args);
+  }
+  // Now we can create the DiagnosticsEngine with a properly-filled-out
+  // DiagnosticOptions instance.
+  TextDiagnosticPrinter *DiagClient
+    = new TextDiagnosticPrinter(llvm::errs(), DiagOpts);
+  DiagClient->setPrefix(llvm::sys::path::stem(Path.str()));
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+
+  DiagnosticsEngine Diags(DiagID, DiagClient);
+  ProcessWarningOptions(Diags, DiagOpts);
+
+#ifdef CLANG_IS_PRODUCTION
+  const bool IsProduction = true;
+#else
+  const bool IsProduction = false;
+#endif
+  Driver TheDriver(Path.str(), llvm::sys::getDefaultTargetTriple(),
+                   "a.out", IsProduction, Diags);
+
+  // Attempt to find the original path used to invoke the driver, to determine
+  // the installed path. We do this manually, because we want to support that
+  // path being a symlink.
+  {
+    SmallString<128> InstalledPath(argv[0]);
+
+    // Do a PATH lookup, if there are no directory components.
+    if (llvm::sys::path::filename(InstalledPath) == InstalledPath) {
+      llvm::sys::Path Tmp = llvm::sys::Program::FindProgramByName(
+        llvm::sys::path::filename(InstalledPath.str()));
+      if (!Tmp.empty())
+        InstalledPath = Tmp.str();
+    }
+    llvm::sys::fs::make_absolute(InstalledPath);
+    InstalledPath = llvm::sys::path::parent_path(InstalledPath);
+    bool exists;
+    if (!llvm::sys::fs::exists(InstalledPath.str(), exists) && exists)
+      TheDriver.setInstalledDir(InstalledPath);
+  }
+
+  llvm::InitializeAllTargets();
+  ParseProgName(argv, SavedStrings, TheDriver);
+
+  // Handle CC_PRINT_OPTIONS and CC_PRINT_OPTIONS_FILE.
+  TheDriver.CCPrintOptions = !!::getenv("CC_PRINT_OPTIONS");
+  if (TheDriver.CCPrintOptions)
+    TheDriver.CCPrintOptionsFilename = ::getenv("CC_PRINT_OPTIONS_FILE");
+
+  // Handle CC_PRINT_HEADERS and CC_PRINT_HEADERS_FILE.
+  TheDriver.CCPrintHeaders = !!::getenv("CC_PRINT_HEADERS");
+  if (TheDriver.CCPrintHeaders)
+    TheDriver.CCPrintHeadersFilename = ::getenv("CC_PRINT_HEADERS_FILE");
+
+  // Handle CC_LOG_DIAGNOSTICS and CC_LOG_DIAGNOSTICS_FILE.
+  TheDriver.CCLogDiagnostics = !!::getenv("CC_LOG_DIAGNOSTICS");
+  if (TheDriver.CCLogDiagnostics)
+    TheDriver.CCLogDiagnosticsFilename = ::getenv("CC_LOG_DIAGNOSTICS_FILE");
+
+  // Handle QA_OVERRIDE_GCC3_OPTIONS and CCC_ADD_ARGS, used for editing a
+  // command line behind the scenes.
+  if (const char *OverrideStr = ::getenv("QA_OVERRIDE_GCC3_OPTIONS")) {
+    // FIXME: Driver shouldn't take extra initial argument.
+    ApplyQAOverride(argv, OverrideStr, SavedStrings);
+  } else if (const char *Cur = ::getenv("CCC_ADD_ARGS")) {
+    // FIXME: Driver shouldn't take extra initial argument.
+    std::vector<const char*> ExtraArgs;
+
+    for (;;) {
+      const char *Next = strchr(Cur, ',');
+
+      if (Next) {
+        ExtraArgs.push_back(SaveStringInSet(SavedStrings,
+                                            std::string(Cur, Next)));
+        Cur = Next + 1;
+      } else {
+        if (*Cur != '\0')
+          ExtraArgs.push_back(SaveStringInSet(SavedStrings, Cur));
+        break;
+      }
+    }
+
+    argv.insert(&argv[1], ExtraArgs.begin(), ExtraArgs.end());
+  }
+
+  OwningPtr<Compilation> C(TheDriver.BuildCompilation(argv));
+  int Res = 0;
+  const Command *FailingCommand = 0;
+  if (C.get())
+    Res = TheDriver.ExecuteCompilation(*C, FailingCommand);
+
+  // If result status is < 0, then the driver command signalled an error.
+  // In this case, generate additional diagnostic information if possible.
+  if (Res < 0)
+    TheDriver.generateCompilationDiagnostics(*C, FailingCommand);
+
+  // If any timers were active but haven't been destroyed yet, print their
+  // results now.  This happens in -disable-free mode.
+  llvm::TimerGroup::printAll(llvm::errs());
+  
+  llvm::llvm_shutdown();
+
+  return Res;
+}