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Diffstat (limited to 'lib/CodeGen/CodeGenFunction.cpp')
-rw-r--r-- | lib/CodeGen/CodeGenFunction.cpp | 714 |
1 files changed, 714 insertions, 0 deletions
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp new file mode 100644 index 0000000..672f6da --- /dev/null +++ b/lib/CodeGen/CodeGenFunction.cpp @@ -0,0 +1,714 @@ +//===--- 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 "CGDebugInfo.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/AST/APValue.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "llvm/Support/CFG.h" +#include "llvm/Target/TargetData.h" +using namespace clang; +using namespace CodeGen; + +CodeGenFunction::CodeGenFunction(CodeGenModule &cgm) + : BlockFunction(cgm, *this, Builder), CGM(cgm), + Target(CGM.getContext().Target), + DebugInfo(0), SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0), + CXXThisDecl(0) { + LLVMIntTy = ConvertType(getContext().IntTy); + LLVMPointerWidth = Target.getPointerWidth(0); +} + +ASTContext &CodeGenFunction::getContext() const { + return CGM.getContext(); +} + + +llvm::BasicBlock *CodeGenFunction::getBasicBlockForLabel(const LabelStmt *S) { + llvm::BasicBlock *&BB = LabelMap[S]; + if (BB) return BB; + + // Create, but don't insert, the new block. + return BB = createBasicBlock(S->getName()); +} + +llvm::Value *CodeGenFunction::GetAddrOfLocalVar(const VarDecl *VD) { + llvm::Value *Res = LocalDeclMap[VD]; + assert(Res && "Invalid argument to GetAddrOfLocalVar(), no decl!"); + return Res; +} + +llvm::Constant * +CodeGenFunction::GetAddrOfStaticLocalVar(const VarDecl *BVD) { + return cast<llvm::Constant>(GetAddrOfLocalVar(BVD)); +} + +const llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { + return CGM.getTypes().ConvertTypeForMem(T); +} + +const llvm::Type *CodeGenFunction::ConvertType(QualType T) { + return CGM.getTypes().ConvertType(T); +} + +bool CodeGenFunction::hasAggregateLLVMType(QualType T) { + // FIXME: Use positive checks instead of negative ones to be more robust in + // the face of extension. + return !T->hasPointerRepresentation() &&!T->isRealType() && + !T->isVoidType() && !T->isVectorType() && !T->isFunctionType() && + !T->isBlockPointerType(); +} + +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 there are no explicit + // jumps to the return block. + if (ReturnBlock->use_empty()) + delete ReturnBlock; + else + EmitBlock(ReturnBlock); + 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->hasOneUse()) { + llvm::BranchInst *BI = + dyn_cast<llvm::BranchInst>(*ReturnBlock->use_begin()); + if (BI && BI->isUnconditional() && BI->getSuccessor(0) == ReturnBlock) { + // Reset insertion point and delete the branch. + Builder.SetInsertPoint(BI->getParent()); + BI->eraseFromParent(); + delete ReturnBlock; + 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); +} + +void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { + // Finish emission of indirect switches. + EmitIndirectSwitches(); + + assert(BreakContinueStack.empty() && + "mismatched push/pop in break/continue stack!"); + assert(BlockScopes.empty() && + "did not remove all blocks from block scope map!"); + assert(CleanupEntries.empty() && + "mismatched push/pop in cleanup stack!"); + + // Emit function epilog (to return). + EmitReturnBlock(); + + // Emit debug descriptor for function end. + if (CGDebugInfo *DI = getDebugInfo()) { + DI->setLocation(EndLoc); + DI->EmitRegionEnd(CurFn, Builder); + } + + EmitFunctionEpilog(*CurFnInfo, ReturnValue); + + // Remove the AllocaInsertPt instruction, which is just a convenience for us. + llvm::Instruction *Ptr = AllocaInsertPt; + AllocaInsertPt = 0; + Ptr->eraseFromParent(); +} + +void CodeGenFunction::StartFunction(const Decl *D, QualType RetTy, + llvm::Function *Fn, + const FunctionArgList &Args, + SourceLocation StartLoc) { + DidCallStackSave = false; + CurCodeDecl = CurFuncDecl = D; + FnRetTy = RetTy; + CurFn = Fn; + assert(CurFn->isDeclaration() && "Function already has body?"); + + 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(llvm::Type::Int32Ty); + AllocaInsertPt = new llvm::BitCastInst(Undef, llvm::Type::Int32Ty, "", + EntryBB); + if (Builder.isNamePreserving()) + AllocaInsertPt->setName("allocapt"); + + ReturnBlock = createBasicBlock("return"); + ReturnValue = 0; + if (!RetTy->isVoidType()) + ReturnValue = CreateTempAlloca(ConvertType(RetTy), "retval"); + + Builder.SetInsertPoint(EntryBB); + + // Emit subprogram debug descriptor. + // FIXME: The cast here is a huge hack. + if (CGDebugInfo *DI = getDebugInfo()) { + DI->setLocation(StartLoc); + if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { + DI->EmitFunctionStart(CGM.getMangledName(FD), RetTy, CurFn, Builder); + } else { + // Just use LLVM function name. + DI->EmitFunctionStart(Fn->getName().c_str(), + RetTy, CurFn, Builder); + } + } + + // FIXME: Leaked. + CurFnInfo = &CGM.getTypes().getFunctionInfo(FnRetTy, Args); + EmitFunctionProlog(*CurFnInfo, CurFn, Args); + + // 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->second; + + if (Ty->isVariablyModifiedType()) + EmitVLASize(Ty); + } +} + +void CodeGenFunction::GenerateCode(const FunctionDecl *FD, + llvm::Function *Fn) { + // Check if we should generate debug info for this function. + if (CGM.getDebugInfo() && !FD->hasAttr<NodebugAttr>()) + DebugInfo = CGM.getDebugInfo(); + + FunctionArgList Args; + + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) { + if (MD->isInstance()) { + // Create the implicit 'this' decl. + // FIXME: I'm not entirely sure I like using a fake decl just for code + // generation. Maybe we can come up with a better way? + CXXThisDecl = ImplicitParamDecl::Create(getContext(), 0, SourceLocation(), + &getContext().Idents.get("this"), + MD->getThisType(getContext())); + Args.push_back(std::make_pair(CXXThisDecl, CXXThisDecl->getType())); + } + } + + if (FD->getNumParams()) { + const FunctionProtoType* FProto = FD->getType()->getAsFunctionProtoType(); + assert(FProto && "Function def must have prototype!"); + + for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) + Args.push_back(std::make_pair(FD->getParamDecl(i), + FProto->getArgType(i))); + } + + // FIXME: Support CXXTryStmt here, too. + if (const CompoundStmt *S = FD->getCompoundBody(getContext())) { + StartFunction(FD, FD->getResultType(), Fn, Args, S->getLBracLoc()); + EmitStmt(S); + FinishFunction(S->getRBracLoc()); + } + + // Destroy the 'this' declaration. + if (CXXThisDecl) + CXXThisDecl->Destroy(getContext()); +} + +/// 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; + 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_iterator I = S->child_begin(), E = S->child_end(); + I != E; ++I) + if (ContainsLabel(*I, IgnoreCaseStmts)) + return true; + + return false; +} + + +/// ConstantFoldsToSimpleInteger - If the sepcified expression does not fold to +/// a constant, or if it does but contains a label, return 0. If it constant +/// folds to 'true' and does not contain a label, return 1, if it constant folds +/// to 'false' and does not contain a label, return -1. +int CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond) { + // FIXME: Rename and handle conversion of other evaluatable things + // to bool. + Expr::EvalResult Result; + if (!Cond->Evaluate(Result, getContext()) || !Result.Val.isInt() || + Result.HasSideEffects) + return 0; // Not foldable, not integer or not fully evaluatable. + + if (CodeGenFunction::ContainsLabel(Cond)) + return 0; // Contains a label. + + return Result.Val.getInt().getBoolValue() ? 1 : -1; +} + + +/// 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) { + if (const ParenExpr *PE = dyn_cast<ParenExpr>(Cond)) + return EmitBranchOnBoolExpr(PE->getSubExpr(), TrueBlock, FalseBlock); + + if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { + // Handle X && Y in a condition. + if (CondBOp->getOpcode() == BinaryOperator::LAnd) { + // If we have "1 && X", simplify the code. "0 && X" would have constant + // folded if the case was simple enough. + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == 1) { + // 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()) == 1) { + // 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"); + EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock); + EmitBlock(LHSTrue); + + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + return; + } else if (CondBOp->getOpcode() == BinaryOperator::LOr) { + // If we have "0 || X", simplify the code. "1 || X" would have constant + // folded if the case was simple enough. + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == -1) { + // 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()) == -1) { + // 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"); + EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse); + EmitBlock(LHSFalse); + + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + return; + } + } + + if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { + // br(!x, t, f) -> br(x, f, t) + if (CondUOp->getOpcode() == UnaryOperator::LNot) + return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock); + } + + if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { + // Handle ?: operator. + + // Just ignore GNU ?: extension. + if (CondOp->getLHS()) { + // 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"); + EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock); + EmitBlock(LHSBlock); + EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock); + EmitBlock(RHSBlock); + EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock); + return; + } + } + + // Emit the code with the fully general case. + llvm::Value *CondV = EvaluateExprAsBool(Cond); + Builder.CreateCondBr(CondV, TrueBlock, FalseBlock); +} + +/// getCGRecordLayout - Return record layout info. +const CGRecordLayout *CodeGenFunction::getCGRecordLayout(CodeGenTypes &CGT, + QualType Ty) { + const RecordType *RTy = Ty->getAsRecordType(); + assert (RTy && "Unexpected type. RecordType expected here."); + + return CGT.getCGRecordLayout(RTy->getDecl()); +} + +/// 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); +} + +unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) { + // Use LabelIDs.size() as the new ID if one hasn't been assigned. + return LabelIDs.insert(std::make_pair(L, LabelIDs.size())).first->second; +} + +void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) { + const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); + if (DestPtr->getType() != BP) + DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp"); + + // Get size and alignment info for this aggregate. + std::pair<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty); + + // Don't bother emitting a zero-byte memset. + if (TypeInfo.first == 0) + return; + + // FIXME: Handle variable sized types. + const llvm::Type *IntPtr = llvm::IntegerType::get(LLVMPointerWidth); + + Builder.CreateCall4(CGM.getMemSetFn(), DestPtr, + llvm::ConstantInt::getNullValue(llvm::Type::Int8Ty), + // TypeInfo.first describes size in bits. + llvm::ConstantInt::get(IntPtr, TypeInfo.first/8), + llvm::ConstantInt::get(llvm::Type::Int32Ty, + TypeInfo.second/8)); +} + +void CodeGenFunction::EmitIndirectSwitches() { + llvm::BasicBlock *Default; + + if (IndirectSwitches.empty()) + return; + + if (!LabelIDs.empty()) { + Default = getBasicBlockForLabel(LabelIDs.begin()->first); + } else { + // No possible targets for indirect goto, just emit an infinite + // loop. + Default = createBasicBlock("indirectgoto.loop", CurFn); + llvm::BranchInst::Create(Default, Default); + } + + for (std::vector<llvm::SwitchInst*>::iterator i = IndirectSwitches.begin(), + e = IndirectSwitches.end(); i != e; ++i) { + llvm::SwitchInst *I = *i; + + I->setSuccessor(0, Default); + for (std::map<const LabelStmt*,unsigned>::iterator LI = LabelIDs.begin(), + LE = LabelIDs.end(); LI != LE; ++LI) { + I->addCase(llvm::ConstantInt::get(llvm::Type::Int32Ty, + LI->second), + getBasicBlockForLabel(LI->first)); + } + } +} + +llvm::Value *CodeGenFunction::GetVLASize(const VariableArrayType *VAT) +{ + llvm::Value *&SizeEntry = VLASizeMap[VAT]; + + assert(SizeEntry && "Did not emit size for type"); + return SizeEntry; +} + +llvm::Value *CodeGenFunction::EmitVLASize(QualType Ty) +{ + assert(Ty->isVariablyModifiedType() && + "Must pass variably modified type to EmitVLASizes!"); + + if (const VariableArrayType *VAT = getContext().getAsVariableArrayType(Ty)) { + llvm::Value *&SizeEntry = VLASizeMap[VAT]; + + if (!SizeEntry) { + // Get the element size; + llvm::Value *ElemSize; + + QualType ElemTy = VAT->getElementType(); + + const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); + + if (ElemTy->isVariableArrayType()) + ElemSize = EmitVLASize(ElemTy); + else { + ElemSize = llvm::ConstantInt::get(SizeTy, + getContext().getTypeSize(ElemTy) / 8); + } + + llvm::Value *NumElements = EmitScalarExpr(VAT->getSizeExpr()); + NumElements = Builder.CreateIntCast(NumElements, SizeTy, false, "tmp"); + + SizeEntry = Builder.CreateMul(ElemSize, NumElements); + } + + return SizeEntry; + } else if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) { + EmitVLASize(AT->getElementType()); + } else if (const PointerType *PT = Ty->getAsPointerType()) + EmitVLASize(PT->getPointeeType()); + else { + assert(0 && "unknown VM type!"); + } + + return 0; +} + +llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { + if (CGM.getContext().getBuiltinVaListType()->isArrayType()) { + return EmitScalarExpr(E); + } + return EmitLValue(E).getAddress(); +} + +void CodeGenFunction::PushCleanupBlock(llvm::BasicBlock *CleanupBlock) +{ + CleanupEntries.push_back(CleanupEntry(CleanupBlock)); +} + +void CodeGenFunction::EmitCleanupBlocks(size_t OldCleanupStackSize) +{ + assert(CleanupEntries.size() >= OldCleanupStackSize && + "Cleanup stack mismatch!"); + + while (CleanupEntries.size() > OldCleanupStackSize) + EmitCleanupBlock(); +} + +CodeGenFunction::CleanupBlockInfo CodeGenFunction::PopCleanupBlock() +{ + CleanupEntry &CE = CleanupEntries.back(); + + llvm::BasicBlock *CleanupBlock = CE.CleanupBlock; + + std::vector<llvm::BasicBlock *> Blocks; + std::swap(Blocks, CE.Blocks); + + std::vector<llvm::BranchInst *> BranchFixups; + std::swap(BranchFixups, CE.BranchFixups); + + CleanupEntries.pop_back(); + + // Check if any branch fixups pointed to the scope we just popped. If so, + // we can remove them. + for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) { + llvm::BasicBlock *Dest = BranchFixups[i]->getSuccessor(0); + BlockScopeMap::iterator I = BlockScopes.find(Dest); + + if (I == BlockScopes.end()) + continue; + + assert(I->second <= CleanupEntries.size() && "Invalid branch fixup!"); + + if (I->second == CleanupEntries.size()) { + // We don't need to do this branch fixup. + BranchFixups[i] = BranchFixups.back(); + BranchFixups.pop_back(); + i--; + e--; + continue; + } + } + + llvm::BasicBlock *SwitchBlock = 0; + llvm::BasicBlock *EndBlock = 0; + if (!BranchFixups.empty()) { + SwitchBlock = createBasicBlock("cleanup.switch"); + EndBlock = createBasicBlock("cleanup.end"); + + llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + + Builder.SetInsertPoint(SwitchBlock); + + llvm::Value *DestCodePtr = CreateTempAlloca(llvm::Type::Int32Ty, + "cleanup.dst"); + llvm::Value *DestCode = Builder.CreateLoad(DestCodePtr, "tmp"); + + // Create a switch instruction to determine where to jump next. + llvm::SwitchInst *SI = Builder.CreateSwitch(DestCode, EndBlock, + BranchFixups.size()); + + // Restore the current basic block (if any) + if (CurBB) { + Builder.SetInsertPoint(CurBB); + + // If we had a current basic block, we also need to emit an instruction + // to initialize the cleanup destination. + Builder.CreateStore(llvm::Constant::getNullValue(llvm::Type::Int32Ty), + DestCodePtr); + } else + Builder.ClearInsertionPoint(); + + for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) { + llvm::BranchInst *BI = BranchFixups[i]; + llvm::BasicBlock *Dest = BI->getSuccessor(0); + + // Fixup the branch instruction to point to the cleanup block. + BI->setSuccessor(0, CleanupBlock); + + if (CleanupEntries.empty()) { + llvm::ConstantInt *ID; + + // Check if we already have a destination for this block. + if (Dest == SI->getDefaultDest()) + ID = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); + else { + ID = SI->findCaseDest(Dest); + if (!ID) { + // No code found, get a new unique one by using the number of + // switch successors. + ID = llvm::ConstantInt::get(llvm::Type::Int32Ty, + SI->getNumSuccessors()); + SI->addCase(ID, Dest); + } + } + + // Store the jump destination before the branch instruction. + new llvm::StoreInst(ID, DestCodePtr, BI); + } else { + // We need to jump through another cleanup block. Create a pad block + // with a branch instruction that jumps to the final destination and + // add it as a branch fixup to the current cleanup scope. + + // Create the pad block. + llvm::BasicBlock *CleanupPad = createBasicBlock("cleanup.pad", CurFn); + + // Create a unique case ID. + llvm::ConstantInt *ID = llvm::ConstantInt::get(llvm::Type::Int32Ty, + SI->getNumSuccessors()); + + // Store the jump destination before the branch instruction. + new llvm::StoreInst(ID, DestCodePtr, BI); + + // Add it as the destination. + SI->addCase(ID, CleanupPad); + + // Create the branch to the final destination. + llvm::BranchInst *BI = llvm::BranchInst::Create(Dest); + CleanupPad->getInstList().push_back(BI); + + // And add it as a branch fixup. + CleanupEntries.back().BranchFixups.push_back(BI); + } + } + } + + // Remove all blocks from the block scope map. + for (size_t i = 0, e = Blocks.size(); i != e; ++i) { + assert(BlockScopes.count(Blocks[i]) && + "Did not find block in scope map!"); + + BlockScopes.erase(Blocks[i]); + } + + return CleanupBlockInfo(CleanupBlock, SwitchBlock, EndBlock); +} + +void CodeGenFunction::EmitCleanupBlock() +{ + CleanupBlockInfo Info = PopCleanupBlock(); + + llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + if (CurBB && !CurBB->getTerminator() && + Info.CleanupBlock->getNumUses() == 0) { + CurBB->getInstList().splice(CurBB->end(), Info.CleanupBlock->getInstList()); + delete Info.CleanupBlock; + } else + EmitBlock(Info.CleanupBlock); + + if (Info.SwitchBlock) + EmitBlock(Info.SwitchBlock); + if (Info.EndBlock) + EmitBlock(Info.EndBlock); +} + +void CodeGenFunction::AddBranchFixup(llvm::BranchInst *BI) +{ + assert(!CleanupEntries.empty() && + "Trying to add branch fixup without cleanup block!"); + + // FIXME: We could be more clever here and check if there's already a branch + // fixup for this destination and recycle it. + CleanupEntries.back().BranchFixups.push_back(BI); +} + +void CodeGenFunction::EmitBranchThroughCleanup(llvm::BasicBlock *Dest) +{ + if (!HaveInsertPoint()) + return; + + llvm::BranchInst* BI = Builder.CreateBr(Dest); + + Builder.ClearInsertionPoint(); + + // The stack is empty, no need to do any cleanup. + if (CleanupEntries.empty()) + return; + + if (!Dest->getParent()) { + // We are trying to branch to a block that hasn't been inserted yet. + AddBranchFixup(BI); + return; + } + + BlockScopeMap::iterator I = BlockScopes.find(Dest); + if (I == BlockScopes.end()) { + // We are trying to jump to a block that is outside of any cleanup scope. + AddBranchFixup(BI); + return; + } + + assert(I->second < CleanupEntries.size() && + "Trying to branch into cleanup region"); + + if (I->second == CleanupEntries.size() - 1) { + // We have a branch to a block in the same scope. + return; + } + + AddBranchFixup(BI); +} |