forked from OSchip/llvm-project
245 lines
8.2 KiB
C++
245 lines
8.2 KiB
C++
//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This coordinates the per-function state used while generating code.
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "CGDebugInfo.h"
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#include "clang/Basic/TargetInfo.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/Decl.h"
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#include "llvm/Support/CFG.h"
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using namespace clang;
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using namespace CodeGen;
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CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
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: CGM(cgm), Target(CGM.getContext().Target), SwitchInsn(NULL),
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CaseRangeBlock(NULL) {
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LLVMIntTy = ConvertType(getContext().IntTy);
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LLVMPointerWidth = Target.getPointerWidth(0);
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}
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ASTContext &CodeGenFunction::getContext() const {
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return CGM.getContext();
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}
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llvm::BasicBlock *CodeGenFunction::getBasicBlockForLabel(const LabelStmt *S) {
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llvm::BasicBlock *&BB = LabelMap[S];
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if (BB) return BB;
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// Create, but don't insert, the new block.
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return BB = llvm::BasicBlock::Create(S->getName());
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}
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llvm::Constant *
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CodeGenFunction::GetAddrOfStaticLocalVar(const VarDecl *BVD) {
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return cast<llvm::Constant>(LocalDeclMap[BVD]);
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}
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llvm::Value *CodeGenFunction::GetAddrOfLocalVar(const VarDecl *VD)
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{
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return LocalDeclMap[VD];
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}
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const llvm::Type *CodeGenFunction::ConvertType(QualType T) {
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return CGM.getTypes().ConvertType(T);
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}
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bool CodeGenFunction::isObjCPointerType(QualType T) {
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// All Objective-C types are pointers.
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return T->isObjCInterfaceType() ||
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T->isObjCQualifiedInterfaceType() || T->isObjCQualifiedIdType();
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}
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bool CodeGenFunction::hasAggregateLLVMType(QualType T) {
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return !isObjCPointerType(T) &&!T->isRealType() && !T->isPointerLikeType() &&
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!T->isVoidType() && !T->isVectorType() && !T->isFunctionType();
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}
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void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
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// Finish emission of indirect switches.
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EmitIndirectSwitches();
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// Emit debug descriptor for function end.
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if (CGDebugInfo *DI = CGM.getDebugInfo()) {
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DI->setLocation(EndLoc);
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DI->EmitRegionEnd(CurFn, Builder);
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}
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assert(BreakContinueStack.empty() &&
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"mismatched push/pop in break/continue stack!");
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// Emit function epilog (to return). This has the nice side effect
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// of also automatically handling code that falls off the end.
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EmitBlock(ReturnBlock);
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EmitFunctionEpilog(FnRetTy, ReturnValue);
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// Remove the AllocaInsertPt instruction, which is just a convenience for us.
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AllocaInsertPt->eraseFromParent();
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AllocaInsertPt = 0;
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}
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void CodeGenFunction::StartFunction(const Decl *D, QualType RetTy,
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llvm::Function *Fn,
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const FunctionArgList &Args,
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SourceLocation StartLoc) {
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CurFuncDecl = D;
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FnRetTy = RetTy;
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CurFn = Fn;
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assert(CurFn->isDeclaration() && "Function already has body?");
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llvm::BasicBlock *EntryBB = llvm::BasicBlock::Create("entry", CurFn);
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// Create a marker to make it easy to insert allocas into the entryblock
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// later. Don't create this with the builder, because we don't want it
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// folded.
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llvm::Value *Undef = llvm::UndefValue::get(llvm::Type::Int32Ty);
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AllocaInsertPt = new llvm::BitCastInst(Undef, llvm::Type::Int32Ty, "allocapt",
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EntryBB);
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ReturnBlock = llvm::BasicBlock::Create("return");
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ReturnValue = 0;
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if (!RetTy->isVoidType())
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ReturnValue = CreateTempAlloca(ConvertType(RetTy), "retval");
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Builder.SetInsertPoint(EntryBB);
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// Emit subprogram debug descriptor.
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// FIXME: The cast here is a huge hack.
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if (CGDebugInfo *DI = CGM.getDebugInfo()) {
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DI->setLocation(StartLoc);
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if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
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DI->EmitFunctionStart(FD->getName(), RetTy, CurFn, Builder);
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} else {
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// Just use LLVM function name.
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DI->EmitFunctionStart(Fn->getName().c_str(),
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RetTy, CurFn, Builder);
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}
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}
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EmitFunctionProlog(CurFn, FnRetTy, Args);
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}
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void CodeGenFunction::GenerateCode(const FunctionDecl *FD,
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llvm::Function *Fn) {
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FunctionArgList Args;
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if (FD->getNumParams()) {
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const FunctionTypeProto* FProto = FD->getType()->getAsFunctionTypeProto();
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assert(FProto && "Function def must have prototype!");
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for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i)
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Args.push_back(std::make_pair(FD->getParamDecl(i),
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FProto->getArgType(i)));
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}
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StartFunction(FD, FD->getResultType(), Fn, Args,
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cast<CompoundStmt>(FD->getBody())->getLBracLoc());
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EmitStmt(FD->getBody());
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const CompoundStmt *S = dyn_cast<CompoundStmt>(FD->getBody());
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if (S) {
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FinishFunction(S->getRBracLoc());
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} else {
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FinishFunction();
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}
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}
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/// isDummyBlock - Return true if BB is an empty basic block
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/// with no predecessors.
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bool CodeGenFunction::isDummyBlock(const llvm::BasicBlock *BB) {
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if (BB->empty() && pred_begin(BB) == pred_end(BB) && !BB->hasName())
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return true;
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return false;
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}
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/// StartBlock - Start new block named N. If insert block is a dummy block
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/// then reuse it.
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void CodeGenFunction::StartBlock(const char *N) {
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llvm::BasicBlock *BB = Builder.GetInsertBlock();
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if (!isDummyBlock(BB))
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EmitBlock(llvm::BasicBlock::Create(N));
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else
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BB->setName(N);
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}
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/// getCGRecordLayout - Return record layout info.
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const CGRecordLayout *CodeGenFunction::getCGRecordLayout(CodeGenTypes &CGT,
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QualType Ty) {
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const RecordType *RTy = Ty->getAsRecordType();
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assert (RTy && "Unexpected type. RecordType expected here.");
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return CGT.getCGRecordLayout(RTy->getDecl());
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}
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/// ErrorUnsupported - Print out an error that codegen doesn't support the
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/// specified stmt yet.
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void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type,
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bool OmitOnError) {
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CGM.ErrorUnsupported(S, Type, OmitOnError);
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}
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unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) {
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// Use LabelIDs.size() as the new ID if one hasn't been assigned.
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return LabelIDs.insert(std::make_pair(L, LabelIDs.size())).first->second;
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}
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void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty)
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{
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const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
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if (DestPtr->getType() != BP)
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DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp");
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// Get size and alignment info for this aggregate.
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std::pair<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty);
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// FIXME: Handle variable sized types.
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const llvm::Type *IntPtr = llvm::IntegerType::get(LLVMPointerWidth);
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Builder.CreateCall4(CGM.getMemSetFn(), DestPtr,
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llvm::ConstantInt::getNullValue(llvm::Type::Int8Ty),
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// TypeInfo.first describes size in bits.
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llvm::ConstantInt::get(IntPtr, TypeInfo.first/8),
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llvm::ConstantInt::get(llvm::Type::Int32Ty,
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TypeInfo.second/8));
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}
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void CodeGenFunction::EmitIndirectSwitches() {
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llvm::BasicBlock *Default;
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if (IndirectSwitches.empty())
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return;
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if (!LabelIDs.empty()) {
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Default = getBasicBlockForLabel(LabelIDs.begin()->first);
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} else {
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// No possible targets for indirect goto, just emit an infinite
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// loop.
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Default = llvm::BasicBlock::Create("indirectgoto.loop", CurFn);
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llvm::BranchInst::Create(Default, Default);
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}
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for (std::vector<llvm::SwitchInst*>::iterator i = IndirectSwitches.begin(),
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e = IndirectSwitches.end(); i != e; ++i) {
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llvm::SwitchInst *I = *i;
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I->setSuccessor(0, Default);
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for (std::map<const LabelStmt*,unsigned>::iterator LI = LabelIDs.begin(),
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LE = LabelIDs.end(); LI != LE; ++LI) {
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I->addCase(llvm::ConstantInt::get(llvm::Type::Int32Ty,
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LI->second),
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getBasicBlockForLabel(LI->first));
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}
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}
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}
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