| //===--- 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 "clang/AST/StmtCXX.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), |
| Builder(cgm.getModule().getContext()), |
| DebugInfo(0), IndirectBranch(0), |
| SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0), |
| CXXThisDecl(0), CXXVTTDecl(0), |
| ConditionalBranchLevel(0), TerminateHandler(0), TrapBB(0), |
| UniqueAggrDestructorCount(0) { |
| LLVMIntTy = ConvertType(getContext().IntTy); |
| LLVMPointerWidth = Target.getPointerWidth(0); |
| Exceptions = getContext().getLangOptions().Exceptions; |
| CatchUndefined = getContext().getLangOptions().CatchUndefined; |
| } |
| |
| 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) { |
| return T->isRecordType() || T->isArrayType() || T->isAnyComplexType() || |
| T->isMemberFunctionPointerType(); |
| } |
| |
| 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->use_empty()) { |
| ReturnBlock->replaceAllUsesWith(CurBB); |
| 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) { |
| 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); |
| EmitEndEHSpec(CurCodeDecl); |
| |
| // 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(); |
| } |
| } |
| } |
| |
| void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, |
| llvm::Function *Fn, |
| const FunctionArgList &Args, |
| SourceLocation StartLoc) { |
| const Decl *D = GD.getDecl(); |
| |
| 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::getInt32Ty(VMContext)); |
| AllocaInsertPt = new llvm::BitCastInst(Undef, |
| llvm::Type::getInt32Ty(VMContext), "", |
| EntryBB); |
| if (Builder.isNamePreserving()) |
| AllocaInsertPt->setName("allocapt"); |
| |
| ReturnBlock = createBasicBlock("return"); |
| |
| Builder.SetInsertPoint(EntryBB); |
| |
| QualType FnType = getContext().getFunctionType(RetTy, 0, 0, false, 0); |
| |
| // Emit subprogram debug descriptor. |
| // FIXME: The cast here is a huge hack. |
| if (CGDebugInfo *DI = getDebugInfo()) { |
| DI->setLocation(StartLoc); |
| if (isa<FunctionDecl>(D)) { |
| DI->EmitFunctionStart(CGM.getMangledName(GD), FnType, CurFn, Builder); |
| } else { |
| // Just use LLVM function name. |
| DI->EmitFunctionStart(Fn->getName(), FnType, CurFn, Builder); |
| } |
| } |
| |
| // FIXME: Leaked. |
| CurFnInfo = &CGM.getTypes().getFunctionInfo(FnRetTy, Args); |
| |
| 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 is also affects correctness in C++. |
| ReturnValue = CurFn->arg_begin(); |
| } else { |
| ReturnValue = CreateTempAlloca(ConvertType(RetTy), "retval"); |
| } |
| |
| EmitStartEHSpec(CurCodeDecl); |
| 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); |
| } |
| } |
| |
| static bool NeedsVTTParameter(GlobalDecl GD) { |
| const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); |
| |
| // We don't have any virtual bases, just return early. |
| if (!MD->getParent()->getNumVBases()) |
| return false; |
| |
| // Check if we have a base constructor. |
| if (isa<CXXConstructorDecl>(MD) && GD.getCtorType() == Ctor_Base) |
| return true; |
| |
| // Check if we have a base destructor. |
| if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) |
| return true; |
| |
| return false; |
| } |
| |
| void CodeGenFunction::GenerateCode(GlobalDecl GD, |
| llvm::Function *Fn) { |
| const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); |
| |
| // Check if we should generate debug info for this function. |
| if (CGM.getDebugInfo() && !FD->hasAttr<NoDebugAttr>()) |
| DebugInfo = CGM.getDebugInfo(); |
| |
| FunctionArgList Args; |
| |
| CurGD = GD; |
| OuterTryBlock = 0; |
| 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())); |
| |
| // Check if we need a VTT parameter as well. |
| if (NeedsVTTParameter(GD)) { |
| // FIXME: The comment about using a fake decl above applies here too. |
| QualType T = getContext().getPointerType(getContext().VoidPtrTy); |
| CXXVTTDecl = |
| ImplicitParamDecl::Create(getContext(), 0, SourceLocation(), |
| &getContext().Idents.get("vtt"), T); |
| Args.push_back(std::make_pair(CXXVTTDecl, CXXVTTDecl->getType())); |
| } |
| } |
| } |
| |
| if (FD->getNumParams()) { |
| const FunctionProtoType* FProto = FD->getType()->getAs<FunctionProtoType>(); |
| 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))); |
| } |
| |
| if (const CompoundStmt *S = FD->getCompoundBody()) { |
| StartFunction(GD, FD->getResultType(), Fn, Args, S->getLBracLoc()); |
| |
| if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { |
| EmitCtorPrologue(CD, GD.getCtorType()); |
| EmitStmt(S); |
| |
| // If any of the member initializers are temporaries bound to references |
| // make sure to emit their destructors. |
| EmitCleanupBlocks(0); |
| |
| } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) { |
| llvm::BasicBlock *DtorEpilogue = createBasicBlock("dtor.epilogue"); |
| PushCleanupBlock(DtorEpilogue); |
| |
| EmitStmt(S); |
| |
| CleanupBlockInfo Info = PopCleanupBlock(); |
| |
| assert(Info.CleanupBlock == DtorEpilogue && "Block mismatch!"); |
| EmitBlock(DtorEpilogue); |
| EmitDtorEpilogue(DD, GD.getDtorType()); |
| |
| if (Info.SwitchBlock) |
| EmitBlock(Info.SwitchBlock); |
| if (Info.EndBlock) |
| EmitBlock(Info.EndBlock); |
| } else { |
| // Just a regular function, emit its body. |
| EmitStmt(S); |
| } |
| |
| FinishFunction(S->getRBracLoc()); |
| } else if (FD->isImplicit()) { |
| const CXXRecordDecl *ClassDecl = |
| cast<CXXRecordDecl>(FD->getDeclContext()); |
| (void) ClassDecl; |
| if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { |
| // FIXME: For C++0x, we want to look for implicit *definitions* of |
| // these special member functions, rather than implicit *declarations*. |
| if (CD->isCopyConstructor()) { |
| assert(!ClassDecl->hasUserDeclaredCopyConstructor() && |
| "Cannot synthesize a non-implicit copy constructor"); |
| SynthesizeCXXCopyConstructor(CD, GD.getCtorType(), Fn, Args); |
| } else if (CD->isDefaultConstructor()) { |
| assert(!ClassDecl->hasUserDeclaredConstructor() && |
| "Cannot synthesize a non-implicit default constructor."); |
| SynthesizeDefaultConstructor(CD, GD.getCtorType(), Fn, Args); |
| } else { |
| assert(false && "Implicit constructor cannot be synthesized"); |
| } |
| } else if (const CXXDestructorDecl *CD = dyn_cast<CXXDestructorDecl>(FD)) { |
| assert(!ClassDecl->hasUserDeclaredDestructor() && |
| "Cannot synthesize a non-implicit destructor"); |
| SynthesizeDefaultDestructor(CD, GD.getDtorType(), Fn, Args); |
| } else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) { |
| assert(MD->isCopyAssignment() && |
| !ClassDecl->hasUserDeclaredCopyAssignment() && |
| "Cannot synthesize a method that is not an implicit-defined " |
| "copy constructor"); |
| SynthesizeCXXCopyAssignment(MD, Fn, Args); |
| } else { |
| assert(false && "Cannot synthesize unknown implicit function"); |
| } |
| } else if (const Stmt *S = FD->getBody()) { |
| if (const CXXTryStmt *TS = dyn_cast<CXXTryStmt>(S)) { |
| OuterTryBlock = TS; |
| StartFunction(GD, FD->getResultType(), Fn, Args, TS->getTryLoc()); |
| EmitStmt(TS); |
| FinishFunction(TS->getEndLoc()); |
| } |
| } |
| |
| // Destroy the 'this' declaration. |
| if (CXXThisDecl) |
| CXXThisDecl->Destroy(getContext()); |
| |
| // Destroy the VTT declaration. |
| if (CXXVTTDecl) |
| CXXVTTDecl->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); |
| } |
| |
| /// 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); |
| } |
| |
| void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) { |
| const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext); |
| 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(VMContext, |
| LLVMPointerWidth); |
| |
| Builder.CreateCall4(CGM.getMemSetFn(), DestPtr, |
| llvm::Constant::getNullValue(llvm::Type::getInt8Ty(VMContext)), |
| // TypeInfo.first describes size in bits. |
| llvm::ConstantInt::get(IntPtr, TypeInfo.first/8), |
| llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), |
| TypeInfo.second/8)); |
| } |
| |
| llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelStmt *L) { |
| // Make sure that there is a block for the indirect goto. |
| if (IndirectBranch == 0) |
| GetIndirectGotoBlock(); |
| |
| llvm::BasicBlock *BB = getBasicBlockForLabel(L); |
| |
| // 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")); |
| |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext); |
| |
| // Create the PHI node that indirect gotos will add entries to. |
| llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, "indirect.goto.dest"); |
| |
| // Create the indirect branch instruction. |
| IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); |
| return IndirectBranch->getParent(); |
| } |
| |
| llvm::Value *CodeGenFunction::GetVLASize(const VariableArrayType *VAT) { |
| llvm::Value *&SizeEntry = VLASizeMap[VAT->getSizeExpr()]; |
| |
| 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!"); |
| |
| EnsureInsertPoint(); |
| |
| if (const VariableArrayType *VAT = getContext().getAsVariableArrayType(Ty)) { |
| llvm::Value *&SizeEntry = VLASizeMap[VAT->getSizeExpr()]; |
| |
| if (!SizeEntry) { |
| const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); |
| |
| // Get the element size; |
| QualType ElemTy = VAT->getElementType(); |
| llvm::Value *ElemSize; |
| 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; |
| } |
| |
| if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) { |
| EmitVLASize(AT->getElementType()); |
| return 0; |
| } |
| |
| const PointerType *PT = Ty->getAs<PointerType>(); |
| assert(PT && "unknown VM type!"); |
| EmitVLASize(PT->getPointeeType()); |
| 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 *CleanupEntryBlock, |
| llvm::BasicBlock *CleanupExitBlock, |
| llvm::BasicBlock *PreviousInvokeDest, |
| bool EHOnly) { |
| CleanupEntries.push_back(CleanupEntry(CleanupEntryBlock, CleanupExitBlock, |
| PreviousInvokeDest, EHOnly)); |
| } |
| |
| 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 *CleanupEntryBlock = CE.CleanupEntryBlock; |
| |
| std::vector<llvm::BasicBlock *> Blocks; |
| std::swap(Blocks, CE.Blocks); |
| |
| std::vector<llvm::BranchInst *> BranchFixups; |
| std::swap(BranchFixups, CE.BranchFixups); |
| |
| bool EHOnly = CE.EHOnly; |
| |
| setInvokeDest(CE.PreviousInvokeDest); |
| |
| 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 = CE.CleanupExitBlock; |
| llvm::BasicBlock *EndBlock = 0; |
| if (!BranchFixups.empty()) { |
| if (!SwitchBlock) |
| SwitchBlock = createBasicBlock("cleanup.switch"); |
| EndBlock = createBasicBlock("cleanup.end"); |
| |
| llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); |
| |
| Builder.SetInsertPoint(SwitchBlock); |
| |
| llvm::Value *DestCodePtr |
| = CreateTempAlloca(llvm::Type::getInt32Ty(VMContext), |
| "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::getInt32Ty(VMContext)), |
| 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, CleanupEntryBlock); |
| |
| 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::getInt32Ty(VMContext), 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::getInt32Ty(VMContext), |
| 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::getInt32Ty(VMContext), |
| 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(CleanupEntryBlock, SwitchBlock, EndBlock, EHOnly); |
| } |
| |
| void CodeGenFunction::EmitCleanupBlock() { |
| CleanupBlockInfo Info = PopCleanupBlock(); |
| |
| if (Info.EHOnly) { |
| // FIXME: Add this to the exceptional edge |
| if (Info.CleanupBlock->getNumUses() == 0) |
| delete Info.CleanupBlock; |
| return; |
| } |
| |
| 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); |
| } |