| //===--- 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 "CGCXXABI.h" |
| #include "CGDebugInfo.h" |
| #include "CGException.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 "clang/Frontend/CodeGenOptions.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Intrinsics.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| static void ResolveAllBranchFixups(CodeGenFunction &CGF, |
| llvm::SwitchInst *Switch, |
| llvm::BasicBlock *CleanupEntry); |
| |
| CodeGenFunction::CodeGenFunction(CodeGenModule &cgm) |
| : BlockFunction(cgm, *this, Builder), CGM(cgm), |
| Target(CGM.getContext().Target), |
| Builder(cgm.getModule().getContext()), |
| NormalCleanupDest(0), EHCleanupDest(0), NextCleanupDestIndex(1), |
| ExceptionSlot(0), DebugInfo(0), IndirectBranch(0), |
| SwitchInsn(0), CaseRangeBlock(0), |
| DidCallStackSave(false), UnreachableBlock(0), |
| CXXThisDecl(0), CXXThisValue(0), CXXVTTDecl(0), CXXVTTValue(0), |
| ConditionalBranchLevel(0), TerminateLandingPad(0), TerminateHandler(0), |
| TrapBB(0) { |
| |
| // Get some frequently used types. |
| LLVMPointerWidth = Target.getPointerWidth(0); |
| llvm::LLVMContext &LLVMContext = CGM.getLLVMContext(); |
| IntPtrTy = llvm::IntegerType::get(LLVMContext, LLVMPointerWidth); |
| Int32Ty = llvm::Type::getInt32Ty(LLVMContext); |
| Int64Ty = llvm::Type::getInt64Ty(LLVMContext); |
| |
| Exceptions = getContext().getLangOptions().Exceptions; |
| CatchUndefined = getContext().getLangOptions().CatchUndefined; |
| CGM.getCXXABI().getMangleContext().startNewFunction(); |
| } |
| |
| ASTContext &CodeGenFunction::getContext() const { |
| return CGM.getContext(); |
| } |
| |
| |
| 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->isObjCObjectType(); |
| } |
| |
| 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 and delete the branch. |
| 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!"); |
| |
| // Emit function epilog (to return). |
| EmitReturnBlock(); |
| |
| 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, RethrowBlock.getBlock()); |
| 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->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) { |
| if (!ShouldInstrumentFunction()) |
| return; |
| |
| const llvm::PointerType *PointerTy; |
| const llvm::FunctionType *FunctionTy; |
| std::vector<const llvm::Type*> ProfileFuncArgs; |
| |
| // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); |
| PointerTy = llvm::Type::getInt8PtrTy(VMContext); |
| ProfileFuncArgs.push_back(PointerTy); |
| ProfileFuncArgs.push_back(PointerTy); |
| FunctionTy = llvm::FunctionType::get( |
| llvm::Type::getVoidTy(VMContext), |
| ProfileFuncArgs, false); |
| |
| llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); |
| llvm::CallInst *CallSite = Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::returnaddress, 0, 0), |
| llvm::ConstantInt::get(Int32Ty, 0), |
| "callsite"); |
| |
| Builder.CreateCall2(F, |
| llvm::ConstantExpr::getBitCast(CurFn, PointerTy), |
| CallSite); |
| } |
| |
| 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?"); |
| |
| // Pass inline keyword to optimizer if it appears explicitly on any |
| // declaration. |
| 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; |
| } |
| |
| 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); |
| |
| QualType FnType = getContext().getFunctionType(RetTy, 0, 0, false, 0, |
| false, false, 0, 0, |
| /*FIXME?*/ |
| FunctionType::ExtInfo()); |
| |
| // Emit subprogram debug descriptor. |
| if (CGDebugInfo *DI = getDebugInfo()) { |
| DI->setLocation(StartLoc); |
| DI->EmitFunctionStart(GD, FnType, CurFn, Builder); |
| } |
| |
| EmitFunctionInstrumentation("__cyg_profile_func_enter"); |
| |
| // FIXME: Leaked. |
| // CC info is ignored, hopefully? |
| CurFnInfo = &CGM.getTypes().getFunctionInfo(FnRetTy, Args, |
| FunctionType::ExtInfo()); |
| |
| 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"); |
| } |
| |
| EmitStartEHSpec(CurCodeDecl); |
| EmitFunctionProlog(*CurFnInfo, CurFn, Args); |
| |
| if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) |
| CGM.getCXXABI().EmitInstanceFunctionProlog(*this); |
| |
| // 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::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; |
| F->setDoesNotThrow(true); |
| } |
| |
| 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; |
| QualType ResTy = FD->getResultType(); |
| |
| CurGD = GD; |
| if (isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isInstance()) |
| CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args); |
| |
| 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))); |
| } |
| |
| SourceRange BodyRange; |
| if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); |
| |
| // Emit the standard function prologue. |
| StartFunction(GD, ResTy, Fn, Args, BodyRange.getBegin()); |
| |
| // Generate the body of the function. |
| if (isa<CXXDestructorDecl>(FD)) |
| EmitDestructorBody(Args); |
| else if (isa<CXXConstructorDecl>(FD)) |
| EmitConstructorBody(Args); |
| 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; |
| 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() == BO_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); |
| |
| // Any temporaries created here are conditional. |
| BeginConditionalBranch(); |
| EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); |
| EndConditionalBranch(); |
| |
| return; |
| } else 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. |
| 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); |
| |
| // Any temporaries created here are conditional. |
| BeginConditionalBranch(); |
| EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); |
| EndConditionalBranch(); |
| |
| 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)) { |
| // 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::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { |
| // Ignore empty classes in C++. |
| if (getContext().getLangOptions().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(); |
| const llvm::Type *BP = |
| llvm::Type::getInt8PtrTy(VMContext, DestAS); |
| 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); |
| uint64_t Size = TypeInfo.first; |
| unsigned Align = TypeInfo.second; |
| |
| // Don't bother emitting a zero-byte memset. |
| if (Size == 0) |
| return; |
| |
| llvm::ConstantInt *SizeVal = llvm::ConstantInt::get(IntPtrTy, Size / 8); |
| llvm::ConstantInt *AlignVal = Builder.getInt32(Align / 8); |
| |
| // 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. |
| if (!CGM.getTypes().isZeroInitializable(Ty)) { |
| llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); |
| |
| llvm::GlobalVariable *NullVariable = |
| new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), |
| /*isConstant=*/true, |
| llvm::GlobalVariable::PrivateLinkage, |
| NullConstant, llvm::Twine()); |
| llvm::Value *SrcPtr = |
| Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()); |
| |
| // FIXME: variable-size types? |
| |
| // Get and call the appropriate llvm.memcpy overload. |
| llvm::Constant *Memcpy = |
| CGM.getMemCpyFn(DestPtr->getType(), SrcPtr->getType(), IntPtrTy); |
| Builder.CreateCall5(Memcpy, DestPtr, SrcPtr, SizeVal, AlignVal, |
| /*volatile*/ Builder.getFalse()); |
| 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. |
| |
| // FIXME: Handle variable sized types. |
| Builder.CreateCall5(CGM.getMemSetFn(BP, IntPtrTy), DestPtr, |
| Builder.getInt8(0), |
| SizeVal, AlignVal, /*volatile*/ Builder.getFalse()); |
| } |
| |
| 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 = 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")); |
| |
| 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)) { |
| // unknown size indication requires no size computation. |
| if (!VAT->getSizeExpr()) |
| return 0; |
| 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().getTypeSizeInChars(ElemTy).getQuantity()); |
| |
| 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(); |
| } |
| |
| /// Pops cleanup blocks until the given savepoint is reached. |
| void CodeGenFunction::PopCleanupBlocks(EHScopeStack::stable_iterator Old) { |
| assert(Old.isValid()); |
| |
| while (EHStack.stable_begin() != Old) { |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin()); |
| |
| // As long as Old strictly encloses the scope's enclosing normal |
| // cleanup, we're going to emit another normal cleanup which |
| // fallthrough can propagate through. |
| bool FallThroughIsBranchThrough = |
| Old.strictlyEncloses(Scope.getEnclosingNormalCleanup()); |
| |
| PopCleanupBlock(FallThroughIsBranchThrough); |
| } |
| } |
| |
| static llvm::BasicBlock *CreateNormalEntry(CodeGenFunction &CGF, |
| EHCleanupScope &Scope) { |
| assert(Scope.isNormalCleanup()); |
| llvm::BasicBlock *Entry = Scope.getNormalBlock(); |
| if (!Entry) { |
| Entry = CGF.createBasicBlock("cleanup"); |
| Scope.setNormalBlock(Entry); |
| } |
| return Entry; |
| } |
| |
| static llvm::BasicBlock *CreateEHEntry(CodeGenFunction &CGF, |
| EHCleanupScope &Scope) { |
| assert(Scope.isEHCleanup()); |
| llvm::BasicBlock *Entry = Scope.getEHBlock(); |
| if (!Entry) { |
| Entry = CGF.createBasicBlock("eh.cleanup"); |
| Scope.setEHBlock(Entry); |
| } |
| return Entry; |
| } |
| |
| /// Transitions the terminator of the given exit-block of a cleanup to |
| /// be a cleanup switch. |
| static llvm::SwitchInst *TransitionToCleanupSwitch(CodeGenFunction &CGF, |
| llvm::BasicBlock *Block) { |
| // If it's a branch, turn it into a switch whose default |
| // destination is its original target. |
| llvm::TerminatorInst *Term = Block->getTerminator(); |
| assert(Term && "can't transition block without terminator"); |
| |
| if (llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Term)) { |
| assert(Br->isUnconditional()); |
| llvm::LoadInst *Load = |
| new llvm::LoadInst(CGF.getNormalCleanupDestSlot(), "cleanup.dest", Term); |
| llvm::SwitchInst *Switch = |
| llvm::SwitchInst::Create(Load, Br->getSuccessor(0), 4, Block); |
| Br->eraseFromParent(); |
| return Switch; |
| } else { |
| return cast<llvm::SwitchInst>(Term); |
| } |
| } |
| |
| /// Attempts to reduce a cleanup's entry block to a fallthrough. This |
| /// is basically llvm::MergeBlockIntoPredecessor, except |
| /// simplified/optimized for the tighter constraints on cleanup blocks. |
| /// |
| /// Returns the new block, whatever it is. |
| static llvm::BasicBlock *SimplifyCleanupEntry(CodeGenFunction &CGF, |
| llvm::BasicBlock *Entry) { |
| llvm::BasicBlock *Pred = Entry->getSinglePredecessor(); |
| if (!Pred) return Entry; |
| |
| llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Pred->getTerminator()); |
| if (!Br || Br->isConditional()) return Entry; |
| assert(Br->getSuccessor(0) == Entry); |
| |
| // If we were previously inserting at the end of the cleanup entry |
| // block, we'll need to continue inserting at the end of the |
| // predecessor. |
| bool WasInsertBlock = CGF.Builder.GetInsertBlock() == Entry; |
| assert(!WasInsertBlock || CGF.Builder.GetInsertPoint() == Entry->end()); |
| |
| // Kill the branch. |
| Br->eraseFromParent(); |
| |
| // Merge the blocks. |
| Pred->getInstList().splice(Pred->end(), Entry->getInstList()); |
| |
| // Kill the entry block. |
| Entry->eraseFromParent(); |
| |
| if (WasInsertBlock) |
| CGF.Builder.SetInsertPoint(Pred); |
| |
| return Pred; |
| } |
| |
| static void EmitCleanup(CodeGenFunction &CGF, |
| EHScopeStack::Cleanup *Fn, |
| bool ForEH, |
| llvm::Value *ActiveFlag) { |
| // EH cleanups always occur within a terminate scope. |
| if (ForEH) CGF.EHStack.pushTerminate(); |
| |
| // If there's an active flag, load it and skip the cleanup if it's |
| // false. |
| llvm::BasicBlock *ContBB = 0; |
| if (ActiveFlag) { |
| ContBB = CGF.createBasicBlock("cleanup.done"); |
| llvm::BasicBlock *CleanupBB = CGF.createBasicBlock("cleanup.action"); |
| llvm::Value *IsActive |
| = CGF.Builder.CreateLoad(ActiveFlag, "cleanup.is_active"); |
| CGF.Builder.CreateCondBr(IsActive, CleanupBB, ContBB); |
| CGF.EmitBlock(CleanupBB); |
| } |
| |
| // Ask the cleanup to emit itself. |
| Fn->Emit(CGF, ForEH); |
| assert(CGF.HaveInsertPoint() && "cleanup ended with no insertion point?"); |
| |
| // Emit the continuation block if there was an active flag. |
| if (ActiveFlag) |
| CGF.EmitBlock(ContBB); |
| |
| // Leave the terminate scope. |
| if (ForEH) CGF.EHStack.popTerminate(); |
| } |
| |
| static void ForwardPrebranchedFallthrough(llvm::BasicBlock *Exit, |
| llvm::BasicBlock *From, |
| llvm::BasicBlock *To) { |
| // Exit is the exit block of a cleanup, so it always terminates in |
| // an unconditional branch or a switch. |
| llvm::TerminatorInst *Term = Exit->getTerminator(); |
| |
| if (llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Term)) { |
| assert(Br->isUnconditional() && Br->getSuccessor(0) == From); |
| Br->setSuccessor(0, To); |
| } else { |
| llvm::SwitchInst *Switch = cast<llvm::SwitchInst>(Term); |
| for (unsigned I = 0, E = Switch->getNumSuccessors(); I != E; ++I) |
| if (Switch->getSuccessor(I) == From) |
| Switch->setSuccessor(I, To); |
| } |
| } |
| |
| /// Pops a cleanup block. If the block includes a normal cleanup, the |
| /// current insertion point is threaded through the cleanup, as are |
| /// any branch fixups on the cleanup. |
| void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) { |
| assert(!EHStack.empty() && "cleanup stack is empty!"); |
| assert(isa<EHCleanupScope>(*EHStack.begin()) && "top not a cleanup!"); |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin()); |
| assert(Scope.getFixupDepth() <= EHStack.getNumBranchFixups()); |
| |
| // Remember activation information. |
| bool IsActive = Scope.isActive(); |
| llvm::Value *NormalActiveFlag = |
| Scope.shouldTestFlagInNormalCleanup() ? Scope.getActiveFlag() : 0; |
| llvm::Value *EHActiveFlag = |
| Scope.shouldTestFlagInEHCleanup() ? Scope.getActiveFlag() : 0; |
| |
| // Check whether we need an EH cleanup. This is only true if we've |
| // generated a lazy EH cleanup block. |
| bool RequiresEHCleanup = Scope.hasEHBranches(); |
| |
| // Check the three conditions which might require a normal cleanup: |
| |
| // - whether there are branch fix-ups through this cleanup |
| unsigned FixupDepth = Scope.getFixupDepth(); |
| bool HasFixups = EHStack.getNumBranchFixups() != FixupDepth; |
| |
| // - whether there are branch-throughs or branch-afters |
| bool HasExistingBranches = Scope.hasBranches(); |
| |
| // - whether there's a fallthrough |
| llvm::BasicBlock *FallthroughSource = Builder.GetInsertBlock(); |
| bool HasFallthrough = (FallthroughSource != 0 && IsActive); |
| |
| // Branch-through fall-throughs leave the insertion point set to the |
| // end of the last cleanup, which points to the current scope. The |
| // rest of IR gen doesn't need to worry about this; it only happens |
| // during the execution of PopCleanupBlocks(). |
| bool HasPrebranchedFallthrough = |
| (FallthroughSource && FallthroughSource->getTerminator()); |
| |
| // If this is a normal cleanup, then having a prebranched |
| // fallthrough implies that the fallthrough source unconditionally |
| // jumps here. |
| assert(!Scope.isNormalCleanup() || !HasPrebranchedFallthrough || |
| (Scope.getNormalBlock() && |
| FallthroughSource->getTerminator()->getSuccessor(0) |
| == Scope.getNormalBlock())); |
| |
| bool RequiresNormalCleanup = false; |
| if (Scope.isNormalCleanup() && |
| (HasFixups || HasExistingBranches || HasFallthrough)) { |
| RequiresNormalCleanup = true; |
| } |
| |
| // Even if we don't need the normal cleanup, we might still have |
| // prebranched fallthrough to worry about. |
| if (Scope.isNormalCleanup() && !RequiresNormalCleanup && |
| HasPrebranchedFallthrough) { |
| assert(!IsActive); |
| |
| llvm::BasicBlock *NormalEntry = Scope.getNormalBlock(); |
| |
| // If we're branching through this cleanup, just forward the |
| // prebranched fallthrough to the next cleanup, leaving the insert |
| // point in the old block. |
| if (FallthroughIsBranchThrough) { |
| EHScope &S = *EHStack.find(Scope.getEnclosingNormalCleanup()); |
| llvm::BasicBlock *EnclosingEntry = |
| CreateNormalEntry(*this, cast<EHCleanupScope>(S)); |
| |
| ForwardPrebranchedFallthrough(FallthroughSource, |
| NormalEntry, EnclosingEntry); |
| assert(NormalEntry->use_empty() && |
| "uses of entry remain after forwarding?"); |
| delete NormalEntry; |
| |
| // Otherwise, we're branching out; just emit the next block. |
| } else { |
| EmitBlock(NormalEntry); |
| SimplifyCleanupEntry(*this, NormalEntry); |
| } |
| } |
| |
| // If we don't need the cleanup at all, we're done. |
| if (!RequiresNormalCleanup && !RequiresEHCleanup) { |
| EHStack.popCleanup(); // safe because there are no fixups |
| assert(EHStack.getNumBranchFixups() == 0 || |
| EHStack.hasNormalCleanups()); |
| return; |
| } |
| |
| // Copy the cleanup emission data out. Note that SmallVector |
| // guarantees maximal alignment for its buffer regardless of its |
| // type parameter. |
| llvm::SmallVector<char, 8*sizeof(void*)> CleanupBuffer; |
| CleanupBuffer.reserve(Scope.getCleanupSize()); |
| memcpy(CleanupBuffer.data(), |
| Scope.getCleanupBuffer(), Scope.getCleanupSize()); |
| CleanupBuffer.set_size(Scope.getCleanupSize()); |
| EHScopeStack::Cleanup *Fn = |
| reinterpret_cast<EHScopeStack::Cleanup*>(CleanupBuffer.data()); |
| |
| // We want to emit the EH cleanup after the normal cleanup, but go |
| // ahead and do the setup for the EH cleanup while the scope is still |
| // alive. |
| llvm::BasicBlock *EHEntry = 0; |
| llvm::SmallVector<llvm::Instruction*, 2> EHInstsToAppend; |
| if (RequiresEHCleanup) { |
| EHEntry = CreateEHEntry(*this, Scope); |
| |
| // Figure out the branch-through dest if necessary. |
| llvm::BasicBlock *EHBranchThroughDest = 0; |
| if (Scope.hasEHBranchThroughs()) { |
| assert(Scope.getEnclosingEHCleanup() != EHStack.stable_end()); |
| EHScope &S = *EHStack.find(Scope.getEnclosingEHCleanup()); |
| EHBranchThroughDest = CreateEHEntry(*this, cast<EHCleanupScope>(S)); |
| } |
| |
| // If we have exactly one branch-after and no branch-throughs, we |
| // can dispatch it without a switch. |
| if (!Scope.hasEHBranchThroughs() && |
| Scope.getNumEHBranchAfters() == 1) { |
| assert(!EHBranchThroughDest); |
| |
| // TODO: remove the spurious eh.cleanup.dest stores if this edge |
| // never went through any switches. |
| llvm::BasicBlock *BranchAfterDest = Scope.getEHBranchAfterBlock(0); |
| EHInstsToAppend.push_back(llvm::BranchInst::Create(BranchAfterDest)); |
| |
| // Otherwise, if we have any branch-afters, we need a switch. |
| } else if (Scope.getNumEHBranchAfters()) { |
| // The default of the switch belongs to the branch-throughs if |
| // they exist. |
| llvm::BasicBlock *Default = |
| (EHBranchThroughDest ? EHBranchThroughDest : getUnreachableBlock()); |
| |
| const unsigned SwitchCapacity = Scope.getNumEHBranchAfters(); |
| |
| llvm::LoadInst *Load = |
| new llvm::LoadInst(getEHCleanupDestSlot(), "cleanup.dest"); |
| llvm::SwitchInst *Switch = |
| llvm::SwitchInst::Create(Load, Default, SwitchCapacity); |
| |
| EHInstsToAppend.push_back(Load); |
| EHInstsToAppend.push_back(Switch); |
| |
| for (unsigned I = 0, E = Scope.getNumEHBranchAfters(); I != E; ++I) |
| Switch->addCase(Scope.getEHBranchAfterIndex(I), |
| Scope.getEHBranchAfterBlock(I)); |
| |
| // Otherwise, we have only branch-throughs; jump to the next EH |
| // cleanup. |
| } else { |
| assert(EHBranchThroughDest); |
| EHInstsToAppend.push_back(llvm::BranchInst::Create(EHBranchThroughDest)); |
| } |
| } |
| |
| if (!RequiresNormalCleanup) { |
| EHStack.popCleanup(); |
| } else { |
| // If we have a fallthrough and no other need for the cleanup, |
| // emit it directly. |
| if (HasFallthrough && !HasPrebranchedFallthrough && |
| !HasFixups && !HasExistingBranches) { |
| |
| // Fixups can cause us to optimistically create a normal block, |
| // only to later have no real uses for it. Just delete it in |
| // this case. |
| // TODO: we can potentially simplify all the uses after this. |
| if (Scope.getNormalBlock()) { |
| Scope.getNormalBlock()->replaceAllUsesWith(getUnreachableBlock()); |
| delete Scope.getNormalBlock(); |
| } |
| |
| EHStack.popCleanup(); |
| |
| EmitCleanup(*this, Fn, /*ForEH*/ false, NormalActiveFlag); |
| |
| // Otherwise, the best approach is to thread everything through |
| // the cleanup block and then try to clean up after ourselves. |
| } else { |
| // Force the entry block to exist. |
| llvm::BasicBlock *NormalEntry = CreateNormalEntry(*this, Scope); |
| |
| // I. Set up the fallthrough edge in. |
| |
| // If there's a fallthrough, we need to store the cleanup |
| // destination index. For fall-throughs this is always zero. |
| if (HasFallthrough) { |
| if (!HasPrebranchedFallthrough) |
| Builder.CreateStore(Builder.getInt32(0), getNormalCleanupDestSlot()); |
| |
| // Otherwise, clear the IP if we don't have fallthrough because |
| // the cleanup is inactive. We don't need to save it because |
| // it's still just FallthroughSource. |
| } else if (FallthroughSource) { |
| assert(!IsActive && "source without fallthrough for active cleanup"); |
| Builder.ClearInsertionPoint(); |
| } |
| |
| // II. Emit the entry block. This implicitly branches to it if |
| // we have fallthrough. All the fixups and existing branches |
| // should already be branched to it. |
| EmitBlock(NormalEntry); |
| |
| // III. Figure out where we're going and build the cleanup |
| // epilogue. |
| |
| bool HasEnclosingCleanups = |
| (Scope.getEnclosingNormalCleanup() != EHStack.stable_end()); |
| |
| // Compute the branch-through dest if we need it: |
| // - if there are branch-throughs threaded through the scope |
| // - if fall-through is a branch-through |
| // - if there are fixups that will be optimistically forwarded |
| // to the enclosing cleanup |
| llvm::BasicBlock *BranchThroughDest = 0; |
| if (Scope.hasBranchThroughs() || |
| (FallthroughSource && FallthroughIsBranchThrough) || |
| (HasFixups && HasEnclosingCleanups)) { |
| assert(HasEnclosingCleanups); |
| EHScope &S = *EHStack.find(Scope.getEnclosingNormalCleanup()); |
| BranchThroughDest = CreateNormalEntry(*this, cast<EHCleanupScope>(S)); |
| } |
| |
| llvm::BasicBlock *FallthroughDest = 0; |
| llvm::SmallVector<llvm::Instruction*, 2> InstsToAppend; |
| |
| // If there's exactly one branch-after and no other threads, |
| // we can route it without a switch. |
| if (!Scope.hasBranchThroughs() && !HasFixups && !HasFallthrough && |
| Scope.getNumBranchAfters() == 1) { |
| assert(!BranchThroughDest || !IsActive); |
| |
| // TODO: clean up the possibly dead stores to the cleanup dest slot. |
| llvm::BasicBlock *BranchAfter = Scope.getBranchAfterBlock(0); |
| InstsToAppend.push_back(llvm::BranchInst::Create(BranchAfter)); |
| |
| // Build a switch-out if we need it: |
| // - if there are branch-afters threaded through the scope |
| // - if fall-through is a branch-after |
| // - if there are fixups that have nowhere left to go and |
| // so must be immediately resolved |
| } else if (Scope.getNumBranchAfters() || |
| (HasFallthrough && !FallthroughIsBranchThrough) || |
| (HasFixups && !HasEnclosingCleanups)) { |
| |
| llvm::BasicBlock *Default = |
| (BranchThroughDest ? BranchThroughDest : getUnreachableBlock()); |
| |
| // TODO: base this on the number of branch-afters and fixups |
| const unsigned SwitchCapacity = 10; |
| |
| llvm::LoadInst *Load = |
| new llvm::LoadInst(getNormalCleanupDestSlot(), "cleanup.dest"); |
| llvm::SwitchInst *Switch = |
| llvm::SwitchInst::Create(Load, Default, SwitchCapacity); |
| |
| InstsToAppend.push_back(Load); |
| InstsToAppend.push_back(Switch); |
| |
| // Branch-after fallthrough. |
| if (FallthroughSource && !FallthroughIsBranchThrough) { |
| FallthroughDest = createBasicBlock("cleanup.cont"); |
| if (HasFallthrough) |
| Switch->addCase(Builder.getInt32(0), FallthroughDest); |
| } |
| |
| for (unsigned I = 0, E = Scope.getNumBranchAfters(); I != E; ++I) { |
| Switch->addCase(Scope.getBranchAfterIndex(I), |
| Scope.getBranchAfterBlock(I)); |
| } |
| |
| // If there aren't any enclosing cleanups, we can resolve all |
| // the fixups now. |
| if (HasFixups && !HasEnclosingCleanups) |
| ResolveAllBranchFixups(*this, Switch, NormalEntry); |
| } else { |
| // We should always have a branch-through destination in this case. |
| assert(BranchThroughDest); |
| InstsToAppend.push_back(llvm::BranchInst::Create(BranchThroughDest)); |
| } |
| |
| // IV. Pop the cleanup and emit it. |
| EHStack.popCleanup(); |
| assert(EHStack.hasNormalCleanups() == HasEnclosingCleanups); |
| |
| EmitCleanup(*this, Fn, /*ForEH*/ false, NormalActiveFlag); |
| |
| // Append the prepared cleanup prologue from above. |
| llvm::BasicBlock *NormalExit = Builder.GetInsertBlock(); |
| for (unsigned I = 0, E = InstsToAppend.size(); I != E; ++I) |
| NormalExit->getInstList().push_back(InstsToAppend[I]); |
| |
| // Optimistically hope that any fixups will continue falling through. |
| for (unsigned I = FixupDepth, E = EHStack.getNumBranchFixups(); |
| I < E; ++I) { |
| BranchFixup &Fixup = CGF.EHStack.getBranchFixup(I); |
| if (!Fixup.Destination) continue; |
| if (!Fixup.OptimisticBranchBlock) { |
| new llvm::StoreInst(Builder.getInt32(Fixup.DestinationIndex), |
| getNormalCleanupDestSlot(), |
| Fixup.InitialBranch); |
| Fixup.InitialBranch->setSuccessor(0, NormalEntry); |
| } |
| Fixup.OptimisticBranchBlock = NormalExit; |
| } |
| |
| // V. Set up the fallthrough edge out. |
| |
| // Case 1: a fallthrough source exists but shouldn't branch to |
| // the cleanup because the cleanup is inactive. |
| if (!HasFallthrough && FallthroughSource) { |
| assert(!IsActive); |
| |
| // If we have a prebranched fallthrough, that needs to be |
| // forwarded to the right block. |
| if (HasPrebranchedFallthrough) { |
| llvm::BasicBlock *Next; |
| if (FallthroughIsBranchThrough) { |
| Next = BranchThroughDest; |
| assert(!FallthroughDest); |
| } else { |
| Next = FallthroughDest; |
| } |
| |
| ForwardPrebranchedFallthrough(FallthroughSource, NormalEntry, Next); |
| } |
| Builder.SetInsertPoint(FallthroughSource); |
| |
| // Case 2: a fallthrough source exists and should branch to the |
| // cleanup, but we're not supposed to branch through to the next |
| // cleanup. |
| } else if (HasFallthrough && FallthroughDest) { |
| assert(!FallthroughIsBranchThrough); |
| EmitBlock(FallthroughDest); |
| |
| // Case 3: a fallthrough source exists and should branch to the |
| // cleanup and then through to the next. |
| } else if (HasFallthrough) { |
| // Everything is already set up for this. |
| |
| // Case 4: no fallthrough source exists. |
| } else { |
| Builder.ClearInsertionPoint(); |
| } |
| |
| // VI. Assorted cleaning. |
| |
| // Check whether we can merge NormalEntry into a single predecessor. |
| // This might invalidate (non-IR) pointers to NormalEntry. |
| llvm::BasicBlock *NewNormalEntry = |
| SimplifyCleanupEntry(*this, NormalEntry); |
| |
| // If it did invalidate those pointers, and NormalEntry was the same |
| // as NormalExit, go back and patch up the fixups. |
| if (NewNormalEntry != NormalEntry && NormalEntry == NormalExit) |
| for (unsigned I = FixupDepth, E = EHStack.getNumBranchFixups(); |
| I < E; ++I) |
| CGF.EHStack.getBranchFixup(I).OptimisticBranchBlock = NewNormalEntry; |
| } |
| } |
| |
| assert(EHStack.hasNormalCleanups() || EHStack.getNumBranchFixups() == 0); |
| |
| // Emit the EH cleanup if required. |
| if (RequiresEHCleanup) { |
| CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP(); |
| |
| EmitBlock(EHEntry); |
| EmitCleanup(*this, Fn, /*ForEH*/ true, EHActiveFlag); |
| |
| // Append the prepared cleanup prologue from above. |
| llvm::BasicBlock *EHExit = Builder.GetInsertBlock(); |
| for (unsigned I = 0, E = EHInstsToAppend.size(); I != E; ++I) |
| EHExit->getInstList().push_back(EHInstsToAppend[I]); |
| |
| Builder.restoreIP(SavedIP); |
| |
| SimplifyCleanupEntry(*this, EHEntry); |
| } |
| } |
| |
| /// Terminate the current block by emitting a branch which might leave |
| /// the current cleanup-protected scope. The target scope may not yet |
| /// be known, in which case this will require a fixup. |
| /// |
| /// As a side-effect, this method clears the insertion point. |
| void CodeGenFunction::EmitBranchThroughCleanup(JumpDest Dest) { |
| assert(Dest.getScopeDepth().encloses(EHStack.getInnermostNormalCleanup()) |
| && "stale jump destination"); |
| |
| if (!HaveInsertPoint()) |
| return; |
| |
| // Create the branch. |
| llvm::BranchInst *BI = Builder.CreateBr(Dest.getBlock()); |
| |
| // Calculate the innermost active normal cleanup. |
| EHScopeStack::stable_iterator |
| TopCleanup = EHStack.getInnermostActiveNormalCleanup(); |
| |
| // If we're not in an active normal cleanup scope, or if the |
| // destination scope is within the innermost active normal cleanup |
| // scope, we don't need to worry about fixups. |
| if (TopCleanup == EHStack.stable_end() || |
| TopCleanup.encloses(Dest.getScopeDepth())) { // works for invalid |
| Builder.ClearInsertionPoint(); |
| return; |
| } |
| |
| // If we can't resolve the destination cleanup scope, just add this |
| // to the current cleanup scope as a branch fixup. |
| if (!Dest.getScopeDepth().isValid()) { |
| BranchFixup &Fixup = EHStack.addBranchFixup(); |
| Fixup.Destination = Dest.getBlock(); |
| Fixup.DestinationIndex = Dest.getDestIndex(); |
| Fixup.InitialBranch = BI; |
| Fixup.OptimisticBranchBlock = 0; |
| |
| Builder.ClearInsertionPoint(); |
| return; |
| } |
| |
| // Otherwise, thread through all the normal cleanups in scope. |
| |
| // Store the index at the start. |
| llvm::ConstantInt *Index = Builder.getInt32(Dest.getDestIndex()); |
| new llvm::StoreInst(Index, getNormalCleanupDestSlot(), BI); |
| |
| // Adjust BI to point to the first cleanup block. |
| { |
| EHCleanupScope &Scope = |
| cast<EHCleanupScope>(*EHStack.find(TopCleanup)); |
| BI->setSuccessor(0, CreateNormalEntry(*this, Scope)); |
| } |
| |
| // Add this destination to all the scopes involved. |
| EHScopeStack::stable_iterator I = TopCleanup; |
| EHScopeStack::stable_iterator E = Dest.getScopeDepth(); |
| if (E.strictlyEncloses(I)) { |
| while (true) { |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(I)); |
| assert(Scope.isNormalCleanup()); |
| I = Scope.getEnclosingNormalCleanup(); |
| |
| // If this is the last cleanup we're propagating through, tell it |
| // that there's a resolved jump moving through it. |
| if (!E.strictlyEncloses(I)) { |
| Scope.addBranchAfter(Index, Dest.getBlock()); |
| break; |
| } |
| |
| // Otherwise, tell the scope that there's a jump propoagating |
| // through it. If this isn't new information, all the rest of |
| // the work has been done before. |
| if (!Scope.addBranchThrough(Dest.getBlock())) |
| break; |
| } |
| } |
| |
| Builder.ClearInsertionPoint(); |
| } |
| |
| void CodeGenFunction::EmitBranchThroughEHCleanup(UnwindDest Dest) { |
| // We should never get invalid scope depths for an UnwindDest; that |
| // implies that the destination wasn't set up correctly. |
| assert(Dest.getScopeDepth().isValid() && "invalid scope depth on EH dest?"); |
| |
| if (!HaveInsertPoint()) |
| return; |
| |
| // Create the branch. |
| llvm::BranchInst *BI = Builder.CreateBr(Dest.getBlock()); |
| |
| // Calculate the innermost active cleanup. |
| EHScopeStack::stable_iterator |
| InnermostCleanup = EHStack.getInnermostActiveEHCleanup(); |
| |
| // If the destination is in the same EH cleanup scope as us, we |
| // don't need to thread through anything. |
| if (InnermostCleanup.encloses(Dest.getScopeDepth())) { |
| Builder.ClearInsertionPoint(); |
| return; |
| } |
| assert(InnermostCleanup != EHStack.stable_end()); |
| |
| // Store the index at the start. |
| llvm::ConstantInt *Index = Builder.getInt32(Dest.getDestIndex()); |
| new llvm::StoreInst(Index, getEHCleanupDestSlot(), BI); |
| |
| // Adjust BI to point to the first cleanup block. |
| { |
| EHCleanupScope &Scope = |
| cast<EHCleanupScope>(*EHStack.find(InnermostCleanup)); |
| BI->setSuccessor(0, CreateEHEntry(*this, Scope)); |
| } |
| |
| // Add this destination to all the scopes involved. |
| for (EHScopeStack::stable_iterator |
| I = InnermostCleanup, E = Dest.getScopeDepth(); ; ) { |
| assert(E.strictlyEncloses(I)); |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(I)); |
| assert(Scope.isEHCleanup()); |
| I = Scope.getEnclosingEHCleanup(); |
| |
| // If this is the last cleanup we're propagating through, add this |
| // as a branch-after. |
| if (I == E) { |
| Scope.addEHBranchAfter(Index, Dest.getBlock()); |
| break; |
| } |
| |
| // Otherwise, add it as a branch-through. If this isn't new |
| // information, all the rest of the work has been done before. |
| if (!Scope.addEHBranchThrough(Dest.getBlock())) |
| break; |
| } |
| |
| Builder.ClearInsertionPoint(); |
| } |
| |
| /// All the branch fixups on the EH stack have propagated out past the |
| /// outermost normal cleanup; resolve them all by adding cases to the |
| /// given switch instruction. |
| static void ResolveAllBranchFixups(CodeGenFunction &CGF, |
| llvm::SwitchInst *Switch, |
| llvm::BasicBlock *CleanupEntry) { |
| llvm::SmallPtrSet<llvm::BasicBlock*, 4> CasesAdded; |
| |
| for (unsigned I = 0, E = CGF.EHStack.getNumBranchFixups(); I != E; ++I) { |
| // Skip this fixup if its destination isn't set. |
| BranchFixup &Fixup = CGF.EHStack.getBranchFixup(I); |
| if (Fixup.Destination == 0) continue; |
| |
| // If there isn't an OptimisticBranchBlock, then InitialBranch is |
| // still pointing directly to its destination; forward it to the |
| // appropriate cleanup entry. This is required in the specific |
| // case of |
| // { std::string s; goto lbl; } |
| // lbl: |
| // i.e. where there's an unresolved fixup inside a single cleanup |
| // entry which we're currently popping. |
| if (Fixup.OptimisticBranchBlock == 0) { |
| new llvm::StoreInst(CGF.Builder.getInt32(Fixup.DestinationIndex), |
| CGF.getNormalCleanupDestSlot(), |
| Fixup.InitialBranch); |
| Fixup.InitialBranch->setSuccessor(0, CleanupEntry); |
| } |
| |
| // Don't add this case to the switch statement twice. |
| if (!CasesAdded.insert(Fixup.Destination)) continue; |
| |
| Switch->addCase(CGF.Builder.getInt32(Fixup.DestinationIndex), |
| Fixup.Destination); |
| } |
| |
| CGF.EHStack.clearFixups(); |
| } |
| |
| void CodeGenFunction::ResolveBranchFixups(llvm::BasicBlock *Block) { |
| assert(Block && "resolving a null target block"); |
| if (!EHStack.getNumBranchFixups()) return; |
| |
| assert(EHStack.hasNormalCleanups() && |
| "branch fixups exist with no normal cleanups on stack"); |
| |
| llvm::SmallPtrSet<llvm::BasicBlock*, 4> ModifiedOptimisticBlocks; |
| bool ResolvedAny = false; |
| |
| for (unsigned I = 0, E = EHStack.getNumBranchFixups(); I != E; ++I) { |
| // Skip this fixup if its destination doesn't match. |
| BranchFixup &Fixup = EHStack.getBranchFixup(I); |
| if (Fixup.Destination != Block) continue; |
| |
| Fixup.Destination = 0; |
| ResolvedAny = true; |
| |
| // If it doesn't have an optimistic branch block, LatestBranch is |
| // already pointing to the right place. |
| llvm::BasicBlock *BranchBB = Fixup.OptimisticBranchBlock; |
| if (!BranchBB) |
| continue; |
| |
| // Don't process the same optimistic branch block twice. |
| if (!ModifiedOptimisticBlocks.insert(BranchBB)) |
| continue; |
| |
| llvm::SwitchInst *Switch = TransitionToCleanupSwitch(*this, BranchBB); |
| |
| // Add a case to the switch. |
| Switch->addCase(Builder.getInt32(Fixup.DestinationIndex), Block); |
| } |
| |
| if (ResolvedAny) |
| EHStack.popNullFixups(); |
| } |
| |
| static bool IsUsedAsNormalCleanup(EHScopeStack &EHStack, |
| EHScopeStack::stable_iterator C) { |
| // If we needed a normal block for any reason, that counts. |
| if (cast<EHCleanupScope>(*EHStack.find(C)).getNormalBlock()) |
| return true; |
| |
| // Check whether any enclosed cleanups were needed. |
| for (EHScopeStack::stable_iterator |
| I = EHStack.getInnermostNormalCleanup(); |
| I != C; ) { |
| assert(C.strictlyEncloses(I)); |
| EHCleanupScope &S = cast<EHCleanupScope>(*EHStack.find(I)); |
| if (S.getNormalBlock()) return true; |
| I = S.getEnclosingNormalCleanup(); |
| } |
| |
| return false; |
| } |
| |
| static bool IsUsedAsEHCleanup(EHScopeStack &EHStack, |
| EHScopeStack::stable_iterator C) { |
| // If we needed an EH block for any reason, that counts. |
| if (cast<EHCleanupScope>(*EHStack.find(C)).getEHBlock()) |
| return true; |
| |
| // Check whether any enclosed cleanups were needed. |
| for (EHScopeStack::stable_iterator |
| I = EHStack.getInnermostEHCleanup(); I != C; ) { |
| assert(C.strictlyEncloses(I)); |
| EHCleanupScope &S = cast<EHCleanupScope>(*EHStack.find(I)); |
| if (S.getEHBlock()) return true; |
| I = S.getEnclosingEHCleanup(); |
| } |
| |
| return false; |
| } |
| |
| enum ForActivation_t { |
| ForActivation, |
| ForDeactivation |
| }; |
| |
| /// The given cleanup block is changing activation state. Configure a |
| /// cleanup variable if necessary. |
| /// |
| /// It would be good if we had some way of determining if there were |
| /// extra uses *after* the change-over point. |
| static void SetupCleanupBlockActivation(CodeGenFunction &CGF, |
| EHScopeStack::stable_iterator C, |
| ForActivation_t Kind) { |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*CGF.EHStack.find(C)); |
| |
| // We always need the flag if we're activating the cleanup, because |
| // we have to assume that the current location doesn't necessarily |
| // dominate all future uses of the cleanup. |
| bool NeedFlag = (Kind == ForActivation); |
| |
| // Calculate whether the cleanup was used: |
| |
| // - as a normal cleanup |
| if (Scope.isNormalCleanup() && IsUsedAsNormalCleanup(CGF.EHStack, C)) { |
| Scope.setTestFlagInNormalCleanup(); |
| NeedFlag = true; |
| } |
| |
| // - as an EH cleanup |
| if (Scope.isEHCleanup() && IsUsedAsEHCleanup(CGF.EHStack, C)) { |
| Scope.setTestFlagInEHCleanup(); |
| NeedFlag = true; |
| } |
| |
| // If it hasn't yet been used as either, we're done. |
| if (!NeedFlag) return; |
| |
| llvm::AllocaInst *Var = Scope.getActiveFlag(); |
| if (!Var) { |
| Var = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "cleanup.isactive"); |
| Scope.setActiveFlag(Var); |
| |
| // Initialize to true or false depending on whether it was |
| // active up to this point. |
| CGF.InitTempAlloca(Var, CGF.Builder.getInt1(Kind == ForDeactivation)); |
| } |
| |
| CGF.Builder.CreateStore(CGF.Builder.getInt1(Kind == ForActivation), Var); |
| } |
| |
| /// Activate a cleanup that was created in an inactivated state. |
| void CodeGenFunction::ActivateCleanupBlock(EHScopeStack::stable_iterator C) { |
| assert(C != EHStack.stable_end() && "activating bottom of stack?"); |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(C)); |
| assert(!Scope.isActive() && "double activation"); |
| |
| SetupCleanupBlockActivation(*this, C, ForActivation); |
| |
| Scope.setActive(true); |
| } |
| |
| /// Deactive a cleanup that was created in an active state. |
| void CodeGenFunction::DeactivateCleanupBlock(EHScopeStack::stable_iterator C) { |
| assert(C != EHStack.stable_end() && "deactivating bottom of stack?"); |
| EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(C)); |
| assert(Scope.isActive() && "double deactivation"); |
| |
| // If it's the top of the stack, just pop it. |
| if (C == EHStack.stable_begin()) { |
| // If it's a normal cleanup, we need to pretend that the |
| // fallthrough is unreachable. |
| CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP(); |
| PopCleanupBlock(); |
| Builder.restoreIP(SavedIP); |
| return; |
| } |
| |
| // Otherwise, follow the general case. |
| SetupCleanupBlockActivation(*this, C, ForDeactivation); |
| |
| Scope.setActive(false); |
| } |
| |
| llvm::Value *CodeGenFunction::getNormalCleanupDestSlot() { |
| if (!NormalCleanupDest) |
| NormalCleanupDest = |
| CreateTempAlloca(Builder.getInt32Ty(), "cleanup.dest.slot"); |
| return NormalCleanupDest; |
| } |
| |
| llvm::Value *CodeGenFunction::getEHCleanupDestSlot() { |
| if (!EHCleanupDest) |
| EHCleanupDest = |
| CreateTempAlloca(Builder.getInt32Ty(), "eh.cleanup.dest.slot"); |
| return EHCleanupDest; |
| } |
| |
| void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, |
| llvm::ConstantInt *Init) { |
| assert (Init && "Invalid DeclRefExpr initializer!"); |
| if (CGDebugInfo *Dbg = getDebugInfo()) |
| Dbg->EmitGlobalVariable(E->getDecl(), Init); |
| } |