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

1 files changed, 1149 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
new file mode 100644
index 0000000..2939062
--- /dev/null
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -0,0 +1,1149 @@
+//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This coordinates the per-function state used while generating code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "CGCUDARuntime.h"
+#include "CGCXXABI.h"
+#include "CGDebugInfo.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/Frontend/CodeGenOptions.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Support/MDBuilder.h"
+#include "llvm/Target/TargetData.h"
+using namespace clang;
+using namespace CodeGen;
+
+CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
+  : CodeGenTypeCache(cgm), CGM(cgm),
+    Target(CGM.getContext().getTargetInfo()),
+    Builder(cgm.getModule().getContext()),
+    AutoreleaseResult(false), BlockInfo(0), BlockPointer(0),
+    LambdaThisCaptureField(0), NormalCleanupDest(0), NextCleanupDestIndex(1),
+    FirstBlockInfo(0), EHResumeBlock(0), ExceptionSlot(0), EHSelectorSlot(0),
+    DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false),
+    IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0),
+    CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0), CXXVTTDecl(0),
+    CXXVTTValue(0), OutermostConditional(0), TerminateLandingPad(0),
+    TerminateHandler(0), TrapBB(0) {
+
+  CatchUndefined = getContext().getLangOpts().CatchUndefined;
+  CGM.getCXXABI().getMangleContext().startNewFunction();
+}
+
+CodeGenFunction::~CodeGenFunction() {
+  // If there are any unclaimed block infos, go ahead and destroy them
+  // now.  This can happen if IR-gen gets clever and skips evaluating
+  // something.
+  if (FirstBlockInfo)
+    destroyBlockInfos(FirstBlockInfo);
+}
+
+
+llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) {
+  return CGM.getTypes().ConvertTypeForMem(T);
+}
+
+llvm::Type *CodeGenFunction::ConvertType(QualType T) {
+  return CGM.getTypes().ConvertType(T);
+}
+
+bool CodeGenFunction::hasAggregateLLVMType(QualType type) {
+  switch (type.getCanonicalType()->getTypeClass()) {
+#define TYPE(name, parent)
+#define ABSTRACT_TYPE(name, parent)
+#define NON_CANONICAL_TYPE(name, parent) case Type::name:
+#define DEPENDENT_TYPE(name, parent) case Type::name:
+#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name:
+#include "clang/AST/TypeNodes.def"
+    llvm_unreachable("non-canonical or dependent type in IR-generation");
+
+  case Type::Builtin:
+  case Type::Pointer:
+  case Type::BlockPointer:
+  case Type::LValueReference:
+  case Type::RValueReference:
+  case Type::MemberPointer:
+  case Type::Vector:
+  case Type::ExtVector:
+  case Type::FunctionProto:
+  case Type::FunctionNoProto:
+  case Type::Enum:
+  case Type::ObjCObjectPointer:
+    return false;
+
+  // Complexes, arrays, records, and Objective-C objects.
+  case Type::Complex:
+  case Type::ConstantArray:
+  case Type::IncompleteArray:
+  case Type::VariableArray:
+  case Type::Record:
+  case Type::ObjCObject:
+  case Type::ObjCInterface:
+    return true;
+
+  // In IRGen, atomic types are just the underlying type
+  case Type::Atomic:
+    return hasAggregateLLVMType(type->getAs<AtomicType>()->getValueType());
+  }
+  llvm_unreachable("unknown type kind!");
+}
+
+void CodeGenFunction::EmitReturnBlock() {
+  // For cleanliness, we try to avoid emitting the return block for
+  // simple cases.
+  llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
+
+  if (CurBB) {
+    assert(!CurBB->getTerminator() && "Unexpected terminated block.");
+
+    // We have a valid insert point, reuse it if it is empty or there are no
+    // explicit jumps to the return block.
+    if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) {
+      ReturnBlock.getBlock()->replaceAllUsesWith(CurBB);
+      delete ReturnBlock.getBlock();
+    } else
+      EmitBlock(ReturnBlock.getBlock());
+    return;
+  }
+
+  // Otherwise, if the return block is the target of a single direct
+  // branch then we can just put the code in that block instead. This
+  // cleans up functions which started with a unified return block.
+  if (ReturnBlock.getBlock()->hasOneUse()) {
+    llvm::BranchInst *BI =
+      dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin());
+    if (BI && BI->isUnconditional() &&
+        BI->getSuccessor(0) == ReturnBlock.getBlock()) {
+      // Reset insertion point, including debug location, and delete the branch.
+      Builder.SetCurrentDebugLocation(BI->getDebugLoc());
+      Builder.SetInsertPoint(BI->getParent());
+      BI->eraseFromParent();
+      delete ReturnBlock.getBlock();
+      return;
+    }
+  }
+
+  // FIXME: We are at an unreachable point, there is no reason to emit the block
+  // unless it has uses. However, we still need a place to put the debug
+  // region.end for now.
+
+  EmitBlock(ReturnBlock.getBlock());
+}
+
+static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) {
+  if (!BB) return;
+  if (!BB->use_empty())
+    return CGF.CurFn->getBasicBlockList().push_back(BB);
+  delete BB;
+}
+
+void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
+  assert(BreakContinueStack.empty() &&
+         "mismatched push/pop in break/continue stack!");
+
+  // Pop any cleanups that might have been associated with the
+  // parameters.  Do this in whatever block we're currently in; it's
+  // important to do this before we enter the return block or return
+  // edges will be *really* confused.
+  if (EHStack.stable_begin() != PrologueCleanupDepth)
+    PopCleanupBlocks(PrologueCleanupDepth);
+
+  // Emit function epilog (to return).
+  EmitReturnBlock();
+
+  if (ShouldInstrumentFunction())
+    EmitFunctionInstrumentation("__cyg_profile_func_exit");
+
+  // Emit debug descriptor for function end.
+  if (CGDebugInfo *DI = getDebugInfo()) {
+    DI->setLocation(EndLoc);
+    DI->EmitFunctionEnd(Builder);
+  }
+
+  EmitFunctionEpilog(*CurFnInfo);
+  EmitEndEHSpec(CurCodeDecl);
+
+  assert(EHStack.empty() &&
+         "did not remove all scopes from cleanup stack!");
+
+  // If someone did an indirect goto, emit the indirect goto block at the end of
+  // the function.
+  if (IndirectBranch) {
+    EmitBlock(IndirectBranch->getParent());
+    Builder.ClearInsertionPoint();
+  }
+  
+  // Remove the AllocaInsertPt instruction, which is just a convenience for us.
+  llvm::Instruction *Ptr = AllocaInsertPt;
+  AllocaInsertPt = 0;
+  Ptr->eraseFromParent();
+  
+  // If someone took the address of a label but never did an indirect goto, we
+  // made a zero entry PHI node, which is illegal, zap it now.
+  if (IndirectBranch) {
+    llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress());
+    if (PN->getNumIncomingValues() == 0) {
+      PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType()));
+      PN->eraseFromParent();
+    }
+  }
+
+  EmitIfUsed(*this, EHResumeBlock);
+  EmitIfUsed(*this, TerminateLandingPad);
+  EmitIfUsed(*this, TerminateHandler);
+  EmitIfUsed(*this, UnreachableBlock);
+
+  if (CGM.getCodeGenOpts().EmitDeclMetadata)
+    EmitDeclMetadata();
+}
+
+/// ShouldInstrumentFunction - Return true if the current function should be
+/// instrumented with __cyg_profile_func_* calls
+bool CodeGenFunction::ShouldInstrumentFunction() {
+  if (!CGM.getCodeGenOpts().InstrumentFunctions)
+    return false;
+  if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>())
+    return false;
+  return true;
+}
+
+/// EmitFunctionInstrumentation - Emit LLVM code to call the specified
+/// instrumentation function with the current function and the call site, if
+/// function instrumentation is enabled.
+void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) {
+  // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site);
+  llvm::PointerType *PointerTy = Int8PtrTy;
+  llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy };
+  llvm::FunctionType *FunctionTy =
+    llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false);
+
+  llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn);
+  llvm::CallInst *CallSite = Builder.CreateCall(
+    CGM.getIntrinsic(llvm::Intrinsic::returnaddress),
+    llvm::ConstantInt::get(Int32Ty, 0),
+    "callsite");
+
+  Builder.CreateCall2(F,
+                      llvm::ConstantExpr::getBitCast(CurFn, PointerTy),
+                      CallSite);
+}
+
+void CodeGenFunction::EmitMCountInstrumentation() {
+  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
+
+  llvm::Constant *MCountFn = CGM.CreateRuntimeFunction(FTy,
+                                                       Target.getMCountName());
+  Builder.CreateCall(MCountFn);
+}
+
+void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
+                                    llvm::Function *Fn,
+                                    const CGFunctionInfo &FnInfo,
+                                    const FunctionArgList &Args,
+                                    SourceLocation StartLoc) {
+  const Decl *D = GD.getDecl();
+  
+  DidCallStackSave = false;
+  CurCodeDecl = CurFuncDecl = D;
+  FnRetTy = RetTy;
+  CurFn = Fn;
+  CurFnInfo = &FnInfo;
+  assert(CurFn->isDeclaration() && "Function already has body?");
+
+  // Pass inline keyword to optimizer if it appears explicitly on any
+  // declaration.
+  if (!CGM.getCodeGenOpts().NoInline) 
+    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
+      for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(),
+             RE = FD->redecls_end(); RI != RE; ++RI)
+        if (RI->isInlineSpecified()) {
+          Fn->addFnAttr(llvm::Attribute::InlineHint);
+          break;
+        }
+
+  if (getContext().getLangOpts().OpenCL) {
+    // Add metadata for a kernel function.
+    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
+      if (FD->hasAttr<OpenCLKernelAttr>()) {
+        llvm::LLVMContext &Context = getLLVMContext();
+        llvm::NamedMDNode *OpenCLMetadata = 
+          CGM.getModule().getOrInsertNamedMetadata("opencl.kernels");
+          
+        llvm::Value *Op = Fn;
+        OpenCLMetadata->addOperand(llvm::MDNode::get(Context, Op));
+      }
+  }
+
+  llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn);
+
+  // Create a marker to make it easy to insert allocas into the entryblock
+  // later.  Don't create this with the builder, because we don't want it
+  // folded.
+  llvm::Value *Undef = llvm::UndefValue::get(Int32Ty);
+  AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB);
+  if (Builder.isNamePreserving())
+    AllocaInsertPt->setName("allocapt");
+
+  ReturnBlock = getJumpDestInCurrentScope("return");
+
+  Builder.SetInsertPoint(EntryBB);
+
+  // Emit subprogram debug descriptor.
+  if (CGDebugInfo *DI = getDebugInfo()) {
+    unsigned NumArgs = 0;
+    QualType *ArgsArray = new QualType[Args.size()];
+    for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
+	 i != e; ++i) {
+      ArgsArray[NumArgs++] = (*i)->getType();
+    }
+
+    QualType FnType =
+      getContext().getFunctionType(RetTy, ArgsArray, NumArgs,
+                                   FunctionProtoType::ExtProtoInfo());
+
+    delete[] ArgsArray;
+
+    DI->setLocation(StartLoc);
+    DI->EmitFunctionStart(GD, FnType, CurFn, Builder);
+  }
+
+  if (ShouldInstrumentFunction())
+    EmitFunctionInstrumentation("__cyg_profile_func_enter");
+
+  if (CGM.getCodeGenOpts().InstrumentForProfiling)
+    EmitMCountInstrumentation();
+
+  if (RetTy->isVoidType()) {
+    // Void type; nothing to return.
+    ReturnValue = 0;
+  } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect &&
+             hasAggregateLLVMType(CurFnInfo->getReturnType())) {
+    // Indirect aggregate return; emit returned value directly into sret slot.
+    // This reduces code size, and affects correctness in C++.
+    ReturnValue = CurFn->arg_begin();
+  } else {
+    ReturnValue = CreateIRTemp(RetTy, "retval");
+
+    // Tell the epilog emitter to autorelease the result.  We do this
+    // now so that various specialized functions can suppress it
+    // during their IR-generation.
+    if (getLangOpts().ObjCAutoRefCount &&
+        !CurFnInfo->isReturnsRetained() &&
+        RetTy->isObjCRetainableType())
+      AutoreleaseResult = true;
+  }
+
+  EmitStartEHSpec(CurCodeDecl);
+
+  PrologueCleanupDepth = EHStack.stable_begin();
+  EmitFunctionProlog(*CurFnInfo, CurFn, Args);
+
+  if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) {
+    CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
+    const CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
+    if (MD->getParent()->isLambda() &&
+        MD->getOverloadedOperator() == OO_Call) {
+      // We're in a lambda; figure out the captures.
+      MD->getParent()->getCaptureFields(LambdaCaptureFields,
+                                        LambdaThisCaptureField);
+      if (LambdaThisCaptureField) {
+        // If this lambda captures this, load it.
+        QualType LambdaTagType =
+            getContext().getTagDeclType(LambdaThisCaptureField->getParent());
+        LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue,
+                                                     LambdaTagType);
+        LValue ThisLValue = EmitLValueForField(LambdaLV,
+                                               LambdaThisCaptureField);
+        CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal();
+      }
+    } else {
+      // Not in a lambda; just use 'this' from the method.
+      // FIXME: Should we generate a new load for each use of 'this'?  The
+      // fast register allocator would be happier...
+      CXXThisValue = CXXABIThisValue;
+    }
+  }
+
+  // If any of the arguments have a variably modified type, make sure to
+  // emit the type size.
+  for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
+       i != e; ++i) {
+    QualType Ty = (*i)->getType();
+
+    if (Ty->isVariablyModifiedType())
+      EmitVariablyModifiedType(Ty);
+  }
+  // Emit a location at the end of the prologue.
+  if (CGDebugInfo *DI = getDebugInfo())
+    DI->EmitLocation(Builder, StartLoc);
+}
+
+void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) {
+  const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl());
+  assert(FD->getBody());
+  EmitStmt(FD->getBody());
+}
+
+/// Tries to mark the given function nounwind based on the
+/// non-existence of any throwing calls within it.  We believe this is
+/// lightweight enough to do at -O0.
+static void TryMarkNoThrow(llvm::Function *F) {
+  // LLVM treats 'nounwind' on a function as part of the type, so we
+  // can't do this on functions that can be overwritten.
+  if (F->mayBeOverridden()) return;
+
+  for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
+    for (llvm::BasicBlock::iterator
+           BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
+      if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) {
+        if (!Call->doesNotThrow())
+          return;
+      } else if (isa<llvm::ResumeInst>(&*BI)) {
+        return;
+      }
+  F->setDoesNotThrow(true);
+}
+
+void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
+                                   const CGFunctionInfo &FnInfo) {
+  const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
+  
+  // Check if we should generate debug info for this function.
+  if (CGM.getModuleDebugInfo() && !FD->hasAttr<NoDebugAttr>())
+    DebugInfo = CGM.getModuleDebugInfo();
+
+  FunctionArgList Args;
+  QualType ResTy = FD->getResultType();
+
+  CurGD = GD;
+  if (isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isInstance())
+    CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args);
+
+  for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i)
+    Args.push_back(FD->getParamDecl(i));
+
+  SourceRange BodyRange;
+  if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange();
+
+  // Emit the standard function prologue.
+  StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin());
+
+  // Generate the body of the function.
+  if (isa<CXXDestructorDecl>(FD))
+    EmitDestructorBody(Args);
+  else if (isa<CXXConstructorDecl>(FD))
+    EmitConstructorBody(Args);
+  else if (getContext().getLangOpts().CUDA &&
+           !CGM.getCodeGenOpts().CUDAIsDevice &&
+           FD->hasAttr<CUDAGlobalAttr>())
+    CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args);
+  else if (isa<CXXConversionDecl>(FD) &&
+           cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) {
+    // The lambda conversion to block pointer is special; the semantics can't be
+    // expressed in the AST, so IRGen needs to special-case it.
+    EmitLambdaToBlockPointerBody(Args);
+  } else if (isa<CXXMethodDecl>(FD) &&
+             cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) {
+    // The lambda "__invoke" function is special, because it forwards or
+    // clones the body of the function call operator (but is actually static).
+    EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD));
+  }
+  else
+    EmitFunctionBody(Args);
+
+  // Emit the standard function epilogue.
+  FinishFunction(BodyRange.getEnd());
+
+  // If we haven't marked the function nothrow through other means, do
+  // a quick pass now to see if we can.
+  if (!CurFn->doesNotThrow())
+    TryMarkNoThrow(CurFn);
+}
+
+/// ContainsLabel - Return true if the statement contains a label in it.  If
+/// this statement is not executed normally, it not containing a label means
+/// that we can just remove the code.
+bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) {
+  // Null statement, not a label!
+  if (S == 0) return false;
+
+  // If this is a label, we have to emit the code, consider something like:
+  // if (0) {  ...  foo:  bar(); }  goto foo;
+  //
+  // TODO: If anyone cared, we could track __label__'s, since we know that you
+  // can't jump to one from outside their declared region.
+  if (isa<LabelStmt>(S))
+    return true;
+  
+  // If this is a case/default statement, and we haven't seen a switch, we have
+  // to emit the code.
+  if (isa<SwitchCase>(S) && !IgnoreCaseStmts)
+    return true;
+
+  // If this is a switch statement, we want to ignore cases below it.
+  if (isa<SwitchStmt>(S))
+    IgnoreCaseStmts = true;
+
+  // Scan subexpressions for verboten labels.
+  for (Stmt::const_child_range I = S->children(); I; ++I)
+    if (ContainsLabel(*I, IgnoreCaseStmts))
+      return true;
+
+  return false;
+}
+
+/// containsBreak - Return true if the statement contains a break out of it.
+/// If the statement (recursively) contains a switch or loop with a break
+/// inside of it, this is fine.
+bool CodeGenFunction::containsBreak(const Stmt *S) {
+  // Null statement, not a label!
+  if (S == 0) return false;
+
+  // If this is a switch or loop that defines its own break scope, then we can
+  // include it and anything inside of it.
+  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) ||
+      isa<ForStmt>(S))
+    return false;
+  
+  if (isa<BreakStmt>(S))
+    return true;
+  
+  // Scan subexpressions for verboten breaks.
+  for (Stmt::const_child_range I = S->children(); I; ++I)
+    if (containsBreak(*I))
+      return true;
+  
+  return false;
+}
+
+
+/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
+/// to a constant, or if it does but contains a label, return false.  If it
+/// constant folds return true and set the boolean result in Result.
+bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
+                                                   bool &ResultBool) {
+  llvm::APInt ResultInt;
+  if (!ConstantFoldsToSimpleInteger(Cond, ResultInt))
+    return false;
+  
+  ResultBool = ResultInt.getBoolValue();
+  return true;
+}
+
+/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
+/// to a constant, or if it does but contains a label, return false.  If it
+/// constant folds return true and set the folded value.
+bool CodeGenFunction::
+ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APInt &ResultInt) {
+  // FIXME: Rename and handle conversion of other evaluatable things
+  // to bool.
+  llvm::APSInt Int;
+  if (!Cond->EvaluateAsInt(Int, getContext()))
+    return false;  // Not foldable, not integer or not fully evaluatable.
+
+  if (CodeGenFunction::ContainsLabel(Cond))
+    return false;  // Contains a label.
+
+  ResultInt = Int;
+  return true;
+}
+
+
+
+/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if
+/// statement) to the specified blocks.  Based on the condition, this might try
+/// to simplify the codegen of the conditional based on the branch.
+///
+void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
+                                           llvm::BasicBlock *TrueBlock,
+                                           llvm::BasicBlock *FalseBlock) {
+  Cond = Cond->IgnoreParens();
+
+  if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
+    // Handle X && Y in a condition.
+    if (CondBOp->getOpcode() == BO_LAnd) {
+      // If we have "1 && X", simplify the code.  "0 && X" would have constant
+      // folded if the case was simple enough.
+      bool ConstantBool = false;
+      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
+          ConstantBool) {
+        // br(1 && X) -> br(X).
+        return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
+      }
+
+      // If we have "X && 1", simplify the code to use an uncond branch.
+      // "X && 0" would have been constant folded to 0.
+      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
+          ConstantBool) {
+        // br(X && 1) -> br(X).
+        return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
+      }
+
+      // Emit the LHS as a conditional.  If the LHS conditional is false, we
+      // want to jump to the FalseBlock.
+      llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true");
+
+      ConditionalEvaluation eval(*this);
+      EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock);
+      EmitBlock(LHSTrue);
+
+      // Any temporaries created here are conditional.
+      eval.begin(*this);
+      EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
+      eval.end(*this);
+
+      return;
+    }
+    
+    if (CondBOp->getOpcode() == BO_LOr) {
+      // If we have "0 || X", simplify the code.  "1 || X" would have constant
+      // folded if the case was simple enough.
+      bool ConstantBool = false;
+      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
+          !ConstantBool) {
+        // br(0 || X) -> br(X).
+        return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
+      }
+
+      // If we have "X || 0", simplify the code to use an uncond branch.
+      // "X || 1" would have been constant folded to 1.
+      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
+          !ConstantBool) {
+        // br(X || 0) -> br(X).
+        return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
+      }
+
+      // Emit the LHS as a conditional.  If the LHS conditional is true, we
+      // want to jump to the TrueBlock.
+      llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false");
+
+      ConditionalEvaluation eval(*this);
+      EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse);
+      EmitBlock(LHSFalse);
+
+      // Any temporaries created here are conditional.
+      eval.begin(*this);
+      EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
+      eval.end(*this);
+
+      return;
+    }
+  }
+
+  if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) {
+    // br(!x, t, f) -> br(x, f, t)
+    if (CondUOp->getOpcode() == UO_LNot)
+      return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock);
+  }
+
+  if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) {
+    // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f))
+    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
+    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
+
+    ConditionalEvaluation cond(*this);
+    EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock);
+
+    cond.begin(*this);
+    EmitBlock(LHSBlock);
+    EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock);
+    cond.end(*this);
+
+    cond.begin(*this);
+    EmitBlock(RHSBlock);
+    EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock);
+    cond.end(*this);
+
+    return;
+  }
+
+  // Emit the code with the fully general case.
+  llvm::Value *CondV = EvaluateExprAsBool(Cond);
+  Builder.CreateCondBr(CondV, TrueBlock, FalseBlock);
+}
+
+/// ErrorUnsupported - Print out an error that codegen doesn't support the
+/// specified stmt yet.
+void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type,
+                                       bool OmitOnError) {
+  CGM.ErrorUnsupported(S, Type, OmitOnError);
+}
+
+/// emitNonZeroVLAInit - Emit the "zero" initialization of a
+/// variable-length array whose elements have a non-zero bit-pattern.
+///
+/// \param src - a char* pointing to the bit-pattern for a single
+/// base element of the array
+/// \param sizeInChars - the total size of the VLA, in chars
+/// \param align - the total alignment of the VLA
+static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType,
+                               llvm::Value *dest, llvm::Value *src, 
+                               llvm::Value *sizeInChars) {
+  std::pair<CharUnits,CharUnits> baseSizeAndAlign
+    = CGF.getContext().getTypeInfoInChars(baseType);
+
+  CGBuilderTy &Builder = CGF.Builder;
+
+  llvm::Value *baseSizeInChars
+    = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity());
+
+  llvm::Type *i8p = Builder.getInt8PtrTy();
+
+  llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin");
+  llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end");
+
+  llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock();
+  llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop");
+  llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont");
+
+  // Make a loop over the VLA.  C99 guarantees that the VLA element
+  // count must be nonzero.
+  CGF.EmitBlock(loopBB);
+
+  llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur");
+  cur->addIncoming(begin, originBB);
+
+  // memcpy the individual element bit-pattern.
+  Builder.CreateMemCpy(cur, src, baseSizeInChars,
+                       baseSizeAndAlign.second.getQuantity(),
+                       /*volatile*/ false);
+
+  // Go to the next element.
+  llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next");
+
+  // Leave if that's the end of the VLA.
+  llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone");
+  Builder.CreateCondBr(done, contBB, loopBB);
+  cur->addIncoming(next, loopBB);
+
+  CGF.EmitBlock(contBB);
+} 
+
+void
+CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
+  // Ignore empty classes in C++.
+  if (getContext().getLangOpts().CPlusPlus) {
+    if (const RecordType *RT = Ty->getAs<RecordType>()) {
+      if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty())
+        return;
+    }
+  }
+
+  // Cast the dest ptr to the appropriate i8 pointer type.
+  unsigned DestAS =
+    cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace();
+  llvm::Type *BP = Builder.getInt8PtrTy(DestAS);
+  if (DestPtr->getType() != BP)
+    DestPtr = Builder.CreateBitCast(DestPtr, BP);
+
+  // Get size and alignment info for this aggregate.
+  std::pair<CharUnits, CharUnits> TypeInfo = 
+    getContext().getTypeInfoInChars(Ty);
+  CharUnits Size = TypeInfo.first;
+  CharUnits Align = TypeInfo.second;
+
+  llvm::Value *SizeVal;
+  const VariableArrayType *vla;
+
+  // Don't bother emitting a zero-byte memset.
+  if (Size.isZero()) {
+    // But note that getTypeInfo returns 0 for a VLA.
+    if (const VariableArrayType *vlaType =
+          dyn_cast_or_null<VariableArrayType>(
+                                          getContext().getAsArrayType(Ty))) {
+      QualType eltType;
+      llvm::Value *numElts;
+      llvm::tie(numElts, eltType) = getVLASize(vlaType);
+
+      SizeVal = numElts;
+      CharUnits eltSize = getContext().getTypeSizeInChars(eltType);
+      if (!eltSize.isOne())
+        SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize));
+      vla = vlaType;
+    } else {
+      return;
+    }
+  } else {
+    SizeVal = CGM.getSize(Size);
+    vla = 0;
+  }
+
+  // If the type contains a pointer to data member we can't memset it to zero.
+  // Instead, create a null constant and copy it to the destination.
+  // TODO: there are other patterns besides zero that we can usefully memset,
+  // like -1, which happens to be the pattern used by member-pointers.
+  if (!CGM.getTypes().isZeroInitializable(Ty)) {
+    // For a VLA, emit a single element, then splat that over the VLA.
+    if (vla) Ty = getContext().getBaseElementType(vla);
+
+    llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty);
+
+    llvm::GlobalVariable *NullVariable = 
+      new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(),
+                               /*isConstant=*/true, 
+                               llvm::GlobalVariable::PrivateLinkage,
+                               NullConstant, Twine());
+    llvm::Value *SrcPtr =
+      Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy());
+
+    if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal);
+
+    // Get and call the appropriate llvm.memcpy overload.
+    Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false);
+    return;
+  } 
+  
+  // Otherwise, just memset the whole thing to zero.  This is legal
+  // because in LLVM, all default initializers (other than the ones we just
+  // handled above) are guaranteed to have a bit pattern of all zeros.
+  Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, 
+                       Align.getQuantity(), false);
+}
+
+llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) {
+  // Make sure that there is a block for the indirect goto.
+  if (IndirectBranch == 0)
+    GetIndirectGotoBlock();
+  
+  llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock();
+  
+  // Make sure the indirect branch includes all of the address-taken blocks.
+  IndirectBranch->addDestination(BB);
+  return llvm::BlockAddress::get(CurFn, BB);
+}
+
+llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
+  // If we already made the indirect branch for indirect goto, return its block.
+  if (IndirectBranch) return IndirectBranch->getParent();
+  
+  CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto"));
+  
+  // Create the PHI node that indirect gotos will add entries to.
+  llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0,
+                                              "indirect.goto.dest");
+  
+  // Create the indirect branch instruction.
+  IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal);
+  return IndirectBranch->getParent();
+}
+
+/// Computes the length of an array in elements, as well as the base
+/// element type and a properly-typed first element pointer.
+llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType,
+                                              QualType &baseType,
+                                              llvm::Value *&addr) {
+  const ArrayType *arrayType = origArrayType;
+
+  // If it's a VLA, we have to load the stored size.  Note that
+  // this is the size of the VLA in bytes, not its size in elements.
+  llvm::Value *numVLAElements = 0;
+  if (isa<VariableArrayType>(arrayType)) {
+    numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first;
+
+    // Walk into all VLAs.  This doesn't require changes to addr,
+    // which has type T* where T is the first non-VLA element type.
+    do {
+      QualType elementType = arrayType->getElementType();
+      arrayType = getContext().getAsArrayType(elementType);
+
+      // If we only have VLA components, 'addr' requires no adjustment.
+      if (!arrayType) {
+        baseType = elementType;
+        return numVLAElements;
+      }
+    } while (isa<VariableArrayType>(arrayType));
+
+    // We get out here only if we find a constant array type
+    // inside the VLA.
+  }
+
+  // We have some number of constant-length arrays, so addr should
+  // have LLVM type [M x [N x [...]]]*.  Build a GEP that walks
+  // down to the first element of addr.
+  SmallVector<llvm::Value*, 8> gepIndices;
+
+  // GEP down to the array type.
+  llvm::ConstantInt *zero = Builder.getInt32(0);
+  gepIndices.push_back(zero);
+
+  // It's more efficient to calculate the count from the LLVM
+  // constant-length arrays than to re-evaluate the array bounds.
+  uint64_t countFromCLAs = 1;
+
+  llvm::ArrayType *llvmArrayType =
+    cast<llvm::ArrayType>(
+      cast<llvm::PointerType>(addr->getType())->getElementType());
+  while (true) {
+    assert(isa<ConstantArrayType>(arrayType));
+    assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue()
+             == llvmArrayType->getNumElements());
+
+    gepIndices.push_back(zero);
+    countFromCLAs *= llvmArrayType->getNumElements();
+
+    llvmArrayType =
+      dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType());
+    if (!llvmArrayType) break;
+
+    arrayType = getContext().getAsArrayType(arrayType->getElementType());
+    assert(arrayType && "LLVM and Clang types are out-of-synch");
+  }
+
+  baseType = arrayType->getElementType();
+
+  // Create the actual GEP.
+  addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin");
+
+  llvm::Value *numElements
+    = llvm::ConstantInt::get(SizeTy, countFromCLAs);
+
+  // If we had any VLA dimensions, factor them in.
+  if (numVLAElements)
+    numElements = Builder.CreateNUWMul(numVLAElements, numElements);
+
+  return numElements;
+}
+
+std::pair<llvm::Value*, QualType>
+CodeGenFunction::getVLASize(QualType type) {
+  const VariableArrayType *vla = getContext().getAsVariableArrayType(type);
+  assert(vla && "type was not a variable array type!");
+  return getVLASize(vla);
+}
+
+std::pair<llvm::Value*, QualType>
+CodeGenFunction::getVLASize(const VariableArrayType *type) {
+  // The number of elements so far; always size_t.
+  llvm::Value *numElements = 0;
+
+  QualType elementType;
+  do {
+    elementType = type->getElementType();
+    llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()];
+    assert(vlaSize && "no size for VLA!");
+    assert(vlaSize->getType() == SizeTy);
+
+    if (!numElements) {
+      numElements = vlaSize;
+    } else {
+      // It's undefined behavior if this wraps around, so mark it that way.
+      numElements = Builder.CreateNUWMul(numElements, vlaSize);
+    }
+  } while ((type = getContext().getAsVariableArrayType(elementType)));
+
+  return std::pair<llvm::Value*,QualType>(numElements, elementType);
+}
+
+void CodeGenFunction::EmitVariablyModifiedType(QualType type) {
+  assert(type->isVariablyModifiedType() &&
+         "Must pass variably modified type to EmitVLASizes!");
+
+  EnsureInsertPoint();
+
+  // We're going to walk down into the type and look for VLA
+  // expressions.
+  do {
+    assert(type->isVariablyModifiedType());
+
+    const Type *ty = type.getTypePtr();
+    switch (ty->getTypeClass()) {
+
+#define TYPE(Class, Base)
+#define ABSTRACT_TYPE(Class, Base)
+#define NON_CANONICAL_TYPE(Class, Base)
+#define DEPENDENT_TYPE(Class, Base) case Type::Class:
+#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base)
+#include "clang/AST/TypeNodes.def"
+      llvm_unreachable("unexpected dependent type!");
+
+    // These types are never variably-modified.
+    case Type::Builtin:
+    case Type::Complex:
+    case Type::Vector:
+    case Type::ExtVector:
+    case Type::Record:
+    case Type::Enum:
+    case Type::Elaborated:
+    case Type::TemplateSpecialization:
+    case Type::ObjCObject:
+    case Type::ObjCInterface:
+    case Type::ObjCObjectPointer:
+      llvm_unreachable("type class is never variably-modified!");
+
+    case Type::Pointer:
+      type = cast<PointerType>(ty)->getPointeeType();
+      break;
+
+    case Type::BlockPointer:
+      type = cast<BlockPointerType>(ty)->getPointeeType();
+      break;
+
+    case Type::LValueReference:
+    case Type::RValueReference:
+      type = cast<ReferenceType>(ty)->getPointeeType();
+      break;
+
+    case Type::MemberPointer:
+      type = cast<MemberPointerType>(ty)->getPointeeType();
+      break;
+
+    case Type::ConstantArray:
+    case Type::IncompleteArray:
+      // Losing element qualification here is fine.
+      type = cast<ArrayType>(ty)->getElementType();
+      break;
+
+    case Type::VariableArray: {
+      // Losing element qualification here is fine.
+      const VariableArrayType *vat = cast<VariableArrayType>(ty);
+
+      // Unknown size indication requires no size computation.
+      // Otherwise, evaluate and record it.
+      if (const Expr *size = vat->getSizeExpr()) {
+        // It's possible that we might have emitted this already,
+        // e.g. with a typedef and a pointer to it.
+        llvm::Value *&entry = VLASizeMap[size];
+        if (!entry) {
+          // Always zexting here would be wrong if it weren't
+          // undefined behavior to have a negative bound.
+          entry = Builder.CreateIntCast(EmitScalarExpr(size), SizeTy,
+                                        /*signed*/ false);
+        }
+      }
+      type = vat->getElementType();
+      break;
+    }
+
+    case Type::FunctionProto:
+    case Type::FunctionNoProto:
+      type = cast<FunctionType>(ty)->getResultType();
+      break;
+
+    case Type::Paren:
+    case Type::TypeOf:
+    case Type::UnaryTransform:
+    case Type::Attributed:
+    case Type::SubstTemplateTypeParm:
+      // Keep walking after single level desugaring.
+      type = type.getSingleStepDesugaredType(getContext());
+      break;
+
+    case Type::Typedef:
+    case Type::Decltype:
+    case Type::Auto:
+      // Stop walking: nothing to do.
+      return;
+
+    case Type::TypeOfExpr:
+      // Stop walking: emit typeof expression.
+      EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr());
+      return;
+
+    case Type::Atomic:
+      type = cast<AtomicType>(ty)->getValueType();
+      break;
+    }
+  } while (type->isVariablyModifiedType());
+}
+
+llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) {
+  if (getContext().getBuiltinVaListType()->isArrayType())
+    return EmitScalarExpr(E);
+  return EmitLValue(E).getAddress();
+}
+
+void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, 
+                                              llvm::Constant *Init) {
+  assert (Init && "Invalid DeclRefExpr initializer!");
+  if (CGDebugInfo *Dbg = getDebugInfo())
+    Dbg->EmitGlobalVariable(E->getDecl(), Init);
+}
+
+CodeGenFunction::PeepholeProtection
+CodeGenFunction::protectFromPeepholes(RValue rvalue) {
+  // At the moment, the only aggressive peephole we do in IR gen
+  // is trunc(zext) folding, but if we add more, we can easily
+  // extend this protection.
+
+  if (!rvalue.isScalar()) return PeepholeProtection();
+  llvm::Value *value = rvalue.getScalarVal();
+  if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection();
+
+  // Just make an extra bitcast.
+  assert(HaveInsertPoint());
+  llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "",
+                                                  Builder.GetInsertBlock());
+
+  PeepholeProtection protection;
+  protection.Inst = inst;
+  return protection;
+}
+
+void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) {
+  if (!protection.Inst) return;
+
+  // In theory, we could try to duplicate the peepholes now, but whatever.
+  protection.Inst->eraseFromParent();
+}
+
+llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn,
+                                                 llvm::Value *AnnotatedVal,
+                                                 llvm::StringRef AnnotationStr,
+                                                 SourceLocation Location) {
+  llvm::Value *Args[4] = {
+    AnnotatedVal,
+    Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy),
+    Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy),
+    CGM.EmitAnnotationLineNo(Location)
+  };
+  return Builder.CreateCall(AnnotationFn, Args);
+}
+
+void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) {
+  assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
+  // FIXME We create a new bitcast for every annotation because that's what
+  // llvm-gcc was doing.
+  for (specific_attr_iterator<AnnotateAttr>
+       ai = D->specific_attr_begin<AnnotateAttr>(),
+       ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai)
+    EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation),
+                       Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()),
+                       (*ai)->getAnnotation(), D->getLocation());
+}
+
+llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
+                                                   llvm::Value *V) {
+  assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
+  llvm::Type *VTy = V->getType();
+  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation,
+                                    CGM.Int8PtrTy);
+
+  for (specific_attr_iterator<AnnotateAttr>
+       ai = D->specific_attr_begin<AnnotateAttr>(),
+       ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) {
+    // FIXME Always emit the cast inst so we can differentiate between
+    // annotation on the first field of a struct and annotation on the struct
+    // itself.
+    if (VTy != CGM.Int8PtrTy)
+      V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy));
+    V = EmitAnnotationCall(F, V, (*ai)->getAnnotation(), D->getLocation());
+    V = Builder.CreateBitCast(V, VTy);
+  }
+
+  return V;
+}