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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp | 1144 |
1 files changed, 1144 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp new file mode 100644 index 0000000..06e90b6 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp @@ -0,0 +1,1144 @@ +//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This coordinates the per-function state used while generating code. +// +//===----------------------------------------------------------------------===// + +#include "CodeGenFunction.h" +#include "CodeGenModule.h" +#include "CGCUDARuntime.h" +#include "CGCXXABI.h" +#include "CGDebugInfo.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtCXX.h" +#include "clang/Frontend/CodeGenOptions.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Intrinsics.h" +using namespace clang; +using namespace CodeGen; + +CodeGenFunction::CodeGenFunction(CodeGenModule &cgm) + : CodeGenTypeCache(cgm), CGM(cgm), + Target(CGM.getContext().getTargetInfo()), + Builder(cgm.getModule().getContext()), + AutoreleaseResult(false), BlockInfo(0), BlockPointer(0), + LambdaThisCaptureField(0), NormalCleanupDest(0), NextCleanupDestIndex(1), + FirstBlockInfo(0), EHResumeBlock(0), ExceptionSlot(0), EHSelectorSlot(0), + DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false), + IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0), + CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0), CXXVTTDecl(0), + CXXVTTValue(0), OutermostConditional(0), TerminateLandingPad(0), + TerminateHandler(0), TrapBB(0) { + + CatchUndefined = getContext().getLangOpts().CatchUndefined; + CGM.getCXXABI().getMangleContext().startNewFunction(); +} + +CodeGenFunction::~CodeGenFunction() { + // If there are any unclaimed block infos, go ahead and destroy them + // now. This can happen if IR-gen gets clever and skips evaluating + // something. + if (FirstBlockInfo) + destroyBlockInfos(FirstBlockInfo); +} + + +llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { + return CGM.getTypes().ConvertTypeForMem(T); +} + +llvm::Type *CodeGenFunction::ConvertType(QualType T) { + return CGM.getTypes().ConvertType(T); +} + +bool CodeGenFunction::hasAggregateLLVMType(QualType type) { + switch (type.getCanonicalType()->getTypeClass()) { +#define TYPE(name, parent) +#define ABSTRACT_TYPE(name, parent) +#define NON_CANONICAL_TYPE(name, parent) case Type::name: +#define DEPENDENT_TYPE(name, parent) case Type::name: +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: +#include "clang/AST/TypeNodes.def" + llvm_unreachable("non-canonical or dependent type in IR-generation"); + + case Type::Builtin: + case Type::Pointer: + case Type::BlockPointer: + case Type::LValueReference: + case Type::RValueReference: + case Type::MemberPointer: + case Type::Vector: + case Type::ExtVector: + case Type::FunctionProto: + case Type::FunctionNoProto: + case Type::Enum: + case Type::ObjCObjectPointer: + return false; + + // Complexes, arrays, records, and Objective-C objects. + case Type::Complex: + case Type::ConstantArray: + case Type::IncompleteArray: + case Type::VariableArray: + case Type::Record: + case Type::ObjCObject: + case Type::ObjCInterface: + return true; + + // In IRGen, atomic types are just the underlying type + case Type::Atomic: + return hasAggregateLLVMType(type->getAs<AtomicType>()->getValueType()); + } + llvm_unreachable("unknown type kind!"); +} + +void CodeGenFunction::EmitReturnBlock() { + // For cleanliness, we try to avoid emitting the return block for + // simple cases. + llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + + if (CurBB) { + assert(!CurBB->getTerminator() && "Unexpected terminated block."); + + // We have a valid insert point, reuse it if it is empty or there are no + // explicit jumps to the return block. + if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { + ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); + delete ReturnBlock.getBlock(); + } else + EmitBlock(ReturnBlock.getBlock()); + return; + } + + // Otherwise, if the return block is the target of a single direct + // branch then we can just put the code in that block instead. This + // cleans up functions which started with a unified return block. + if (ReturnBlock.getBlock()->hasOneUse()) { + llvm::BranchInst *BI = + dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin()); + if (BI && BI->isUnconditional() && + BI->getSuccessor(0) == ReturnBlock.getBlock()) { + // Reset insertion point, including debug location, and delete the branch. + Builder.SetCurrentDebugLocation(BI->getDebugLoc()); + Builder.SetInsertPoint(BI->getParent()); + BI->eraseFromParent(); + delete ReturnBlock.getBlock(); + return; + } + } + + // FIXME: We are at an unreachable point, there is no reason to emit the block + // unless it has uses. However, we still need a place to put the debug + // region.end for now. + + EmitBlock(ReturnBlock.getBlock()); +} + +static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { + if (!BB) return; + if (!BB->use_empty()) + return CGF.CurFn->getBasicBlockList().push_back(BB); + delete BB; +} + +void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { + assert(BreakContinueStack.empty() && + "mismatched push/pop in break/continue stack!"); + + // Pop any cleanups that might have been associated with the + // parameters. Do this in whatever block we're currently in; it's + // important to do this before we enter the return block or return + // edges will be *really* confused. + if (EHStack.stable_begin() != PrologueCleanupDepth) + PopCleanupBlocks(PrologueCleanupDepth); + + // Emit function epilog (to return). + EmitReturnBlock(); + + if (ShouldInstrumentFunction()) + EmitFunctionInstrumentation("__cyg_profile_func_exit"); + + // Emit debug descriptor for function end. + if (CGDebugInfo *DI = getDebugInfo()) { + DI->setLocation(EndLoc); + DI->EmitFunctionEnd(Builder); + } + + EmitFunctionEpilog(*CurFnInfo); + EmitEndEHSpec(CurCodeDecl); + + assert(EHStack.empty() && + "did not remove all scopes from cleanup stack!"); + + // If someone did an indirect goto, emit the indirect goto block at the end of + // the function. + if (IndirectBranch) { + EmitBlock(IndirectBranch->getParent()); + Builder.ClearInsertionPoint(); + } + + // Remove the AllocaInsertPt instruction, which is just a convenience for us. + llvm::Instruction *Ptr = AllocaInsertPt; + AllocaInsertPt = 0; + Ptr->eraseFromParent(); + + // If someone took the address of a label but never did an indirect goto, we + // made a zero entry PHI node, which is illegal, zap it now. + if (IndirectBranch) { + llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); + if (PN->getNumIncomingValues() == 0) { + PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); + PN->eraseFromParent(); + } + } + + EmitIfUsed(*this, EHResumeBlock); + EmitIfUsed(*this, TerminateLandingPad); + EmitIfUsed(*this, TerminateHandler); + EmitIfUsed(*this, UnreachableBlock); + + if (CGM.getCodeGenOpts().EmitDeclMetadata) + EmitDeclMetadata(); +} + +/// ShouldInstrumentFunction - Return true if the current function should be +/// instrumented with __cyg_profile_func_* calls +bool CodeGenFunction::ShouldInstrumentFunction() { + if (!CGM.getCodeGenOpts().InstrumentFunctions) + return false; + if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) + return false; + return true; +} + +/// EmitFunctionInstrumentation - Emit LLVM code to call the specified +/// instrumentation function with the current function and the call site, if +/// function instrumentation is enabled. +void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) { + // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); + llvm::PointerType *PointerTy = Int8PtrTy; + llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy }; + llvm::FunctionType *FunctionTy = + llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false); + + llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); + llvm::CallInst *CallSite = Builder.CreateCall( + CGM.getIntrinsic(llvm::Intrinsic::returnaddress), + llvm::ConstantInt::get(Int32Ty, 0), + "callsite"); + + Builder.CreateCall2(F, + llvm::ConstantExpr::getBitCast(CurFn, PointerTy), + CallSite); +} + +void CodeGenFunction::EmitMCountInstrumentation() { + llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); + + llvm::Constant *MCountFn = CGM.CreateRuntimeFunction(FTy, + Target.getMCountName()); + Builder.CreateCall(MCountFn); +} + +void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, + llvm::Function *Fn, + const CGFunctionInfo &FnInfo, + const FunctionArgList &Args, + SourceLocation StartLoc) { + const Decl *D = GD.getDecl(); + + DidCallStackSave = false; + CurCodeDecl = CurFuncDecl = D; + FnRetTy = RetTy; + CurFn = Fn; + CurFnInfo = &FnInfo; + assert(CurFn->isDeclaration() && "Function already has body?"); + + // Pass inline keyword to optimizer if it appears explicitly on any + // declaration. + if (!CGM.getCodeGenOpts().NoInline) + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(), + RE = FD->redecls_end(); RI != RE; ++RI) + if (RI->isInlineSpecified()) { + Fn->addFnAttr(llvm::Attribute::InlineHint); + break; + } + + if (getContext().getLangOpts().OpenCL) { + // Add metadata for a kernel function. + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + if (FD->hasAttr<OpenCLKernelAttr>()) { + llvm::LLVMContext &Context = getLLVMContext(); + llvm::NamedMDNode *OpenCLMetadata = + CGM.getModule().getOrInsertNamedMetadata("opencl.kernels"); + + llvm::Value *Op = Fn; + OpenCLMetadata->addOperand(llvm::MDNode::get(Context, Op)); + } + } + + llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); + + // Create a marker to make it easy to insert allocas into the entryblock + // later. Don't create this with the builder, because we don't want it + // folded. + llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); + AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB); + if (Builder.isNamePreserving()) + AllocaInsertPt->setName("allocapt"); + + ReturnBlock = getJumpDestInCurrentScope("return"); + + Builder.SetInsertPoint(EntryBB); + + // Emit subprogram debug descriptor. + if (CGDebugInfo *DI = getDebugInfo()) { + unsigned NumArgs = 0; + QualType *ArgsArray = new QualType[Args.size()]; + for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); + i != e; ++i) { + ArgsArray[NumArgs++] = (*i)->getType(); + } + + QualType FnType = + getContext().getFunctionType(RetTy, ArgsArray, NumArgs, + FunctionProtoType::ExtProtoInfo()); + + delete[] ArgsArray; + + DI->setLocation(StartLoc); + DI->EmitFunctionStart(GD, FnType, CurFn, Builder); + } + + if (ShouldInstrumentFunction()) + EmitFunctionInstrumentation("__cyg_profile_func_enter"); + + if (CGM.getCodeGenOpts().InstrumentForProfiling) + EmitMCountInstrumentation(); + + if (RetTy->isVoidType()) { + // Void type; nothing to return. + ReturnValue = 0; + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && + hasAggregateLLVMType(CurFnInfo->getReturnType())) { + // Indirect aggregate return; emit returned value directly into sret slot. + // This reduces code size, and affects correctness in C++. + ReturnValue = CurFn->arg_begin(); + } else { + ReturnValue = CreateIRTemp(RetTy, "retval"); + + // Tell the epilog emitter to autorelease the result. We do this + // now so that various specialized functions can suppress it + // during their IR-generation. + if (getLangOpts().ObjCAutoRefCount && + !CurFnInfo->isReturnsRetained() && + RetTy->isObjCRetainableType()) + AutoreleaseResult = true; + } + + EmitStartEHSpec(CurCodeDecl); + + PrologueCleanupDepth = EHStack.stable_begin(); + EmitFunctionProlog(*CurFnInfo, CurFn, Args); + + if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { + CGM.getCXXABI().EmitInstanceFunctionProlog(*this); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); + if (MD->getParent()->isLambda() && + MD->getOverloadedOperator() == OO_Call) { + // We're in a lambda; figure out the captures. + MD->getParent()->getCaptureFields(LambdaCaptureFields, + LambdaThisCaptureField); + if (LambdaThisCaptureField) { + // If this lambda captures this, load it. + LValue ThisLValue = EmitLValueForField(CXXABIThisValue, + LambdaThisCaptureField, 0); + CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal(); + } + } else { + // Not in a lambda; just use 'this' from the method. + // FIXME: Should we generate a new load for each use of 'this'? The + // fast register allocator would be happier... + CXXThisValue = CXXABIThisValue; + } + } + + // If any of the arguments have a variably modified type, make sure to + // emit the type size. + for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); + i != e; ++i) { + QualType Ty = (*i)->getType(); + + if (Ty->isVariablyModifiedType()) + EmitVariablyModifiedType(Ty); + } + // Emit a location at the end of the prologue. + if (CGDebugInfo *DI = getDebugInfo()) + DI->EmitLocation(Builder, StartLoc); +} + +void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) { + const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl()); + assert(FD->getBody()); + EmitStmt(FD->getBody()); +} + +/// Tries to mark the given function nounwind based on the +/// non-existence of any throwing calls within it. We believe this is +/// lightweight enough to do at -O0. +static void TryMarkNoThrow(llvm::Function *F) { + // LLVM treats 'nounwind' on a function as part of the type, so we + // can't do this on functions that can be overwritten. + if (F->mayBeOverridden()) return; + + for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI) + for (llvm::BasicBlock::iterator + BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) + if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) { + if (!Call->doesNotThrow()) + return; + } else if (isa<llvm::ResumeInst>(&*BI)) { + return; + } + F->setDoesNotThrow(true); +} + +void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, + const CGFunctionInfo &FnInfo) { + const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); + + // Check if we should generate debug info for this function. + if (CGM.getModuleDebugInfo() && !FD->hasAttr<NoDebugAttr>()) + DebugInfo = CGM.getModuleDebugInfo(); + + FunctionArgList Args; + QualType ResTy = FD->getResultType(); + + CurGD = GD; + if (isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isInstance()) + CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args); + + for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) + Args.push_back(FD->getParamDecl(i)); + + SourceRange BodyRange; + if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); + + // Emit the standard function prologue. + StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin()); + + // Generate the body of the function. + if (isa<CXXDestructorDecl>(FD)) + EmitDestructorBody(Args); + else if (isa<CXXConstructorDecl>(FD)) + EmitConstructorBody(Args); + else if (getContext().getLangOpts().CUDA && + !CGM.getCodeGenOpts().CUDAIsDevice && + FD->hasAttr<CUDAGlobalAttr>()) + CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args); + else if (isa<CXXConversionDecl>(FD) && + cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) { + // The lambda conversion to block pointer is special; the semantics can't be + // expressed in the AST, so IRGen needs to special-case it. + EmitLambdaToBlockPointerBody(Args); + } else if (isa<CXXMethodDecl>(FD) && + cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { + // The lambda "__invoke" function is special, because it forwards or + // clones the body of the function call operator (but is actually static). + EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD)); + } + else + EmitFunctionBody(Args); + + // Emit the standard function epilogue. + FinishFunction(BodyRange.getEnd()); + + // If we haven't marked the function nothrow through other means, do + // a quick pass now to see if we can. + if (!CurFn->doesNotThrow()) + TryMarkNoThrow(CurFn); +} + +/// ContainsLabel - Return true if the statement contains a label in it. If +/// this statement is not executed normally, it not containing a label means +/// that we can just remove the code. +bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { + // Null statement, not a label! + if (S == 0) return false; + + // If this is a label, we have to emit the code, consider something like: + // if (0) { ... foo: bar(); } goto foo; + // + // TODO: If anyone cared, we could track __label__'s, since we know that you + // can't jump to one from outside their declared region. + if (isa<LabelStmt>(S)) + return true; + + // If this is a case/default statement, and we haven't seen a switch, we have + // to emit the code. + if (isa<SwitchCase>(S) && !IgnoreCaseStmts) + return true; + + // If this is a switch statement, we want to ignore cases below it. + if (isa<SwitchStmt>(S)) + IgnoreCaseStmts = true; + + // Scan subexpressions for verboten labels. + for (Stmt::const_child_range I = S->children(); I; ++I) + if (ContainsLabel(*I, IgnoreCaseStmts)) + return true; + + return false; +} + +/// containsBreak - Return true if the statement contains a break out of it. +/// If the statement (recursively) contains a switch or loop with a break +/// inside of it, this is fine. +bool CodeGenFunction::containsBreak(const Stmt *S) { + // Null statement, not a label! + if (S == 0) return false; + + // If this is a switch or loop that defines its own break scope, then we can + // include it and anything inside of it. + if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || + isa<ForStmt>(S)) + return false; + + if (isa<BreakStmt>(S)) + return true; + + // Scan subexpressions for verboten breaks. + for (Stmt::const_child_range I = S->children(); I; ++I) + if (containsBreak(*I)) + return true; + + return false; +} + + +/// ConstantFoldsToSimpleInteger - If the specified expression does not fold +/// to a constant, or if it does but contains a label, return false. If it +/// constant folds return true and set the boolean result in Result. +bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, + bool &ResultBool) { + llvm::APInt ResultInt; + if (!ConstantFoldsToSimpleInteger(Cond, ResultInt)) + return false; + + ResultBool = ResultInt.getBoolValue(); + return true; +} + +/// ConstantFoldsToSimpleInteger - If the specified expression does not fold +/// to a constant, or if it does but contains a label, return false. If it +/// constant folds return true and set the folded value. +bool CodeGenFunction:: +ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APInt &ResultInt) { + // FIXME: Rename and handle conversion of other evaluatable things + // to bool. + llvm::APSInt Int; + if (!Cond->EvaluateAsInt(Int, getContext())) + return false; // Not foldable, not integer or not fully evaluatable. + + if (CodeGenFunction::ContainsLabel(Cond)) + return false; // Contains a label. + + ResultInt = Int; + return true; +} + + + +/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if +/// statement) to the specified blocks. Based on the condition, this might try +/// to simplify the codegen of the conditional based on the branch. +/// +void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, + llvm::BasicBlock *TrueBlock, + llvm::BasicBlock *FalseBlock) { + Cond = Cond->IgnoreParens(); + + if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { + // Handle X && Y in a condition. + if (CondBOp->getOpcode() == BO_LAnd) { + // If we have "1 && X", simplify the code. "0 && X" would have constant + // folded if the case was simple enough. + bool ConstantBool = false; + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && + ConstantBool) { + // br(1 && X) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + } + + // If we have "X && 1", simplify the code to use an uncond branch. + // "X && 0" would have been constant folded to 0. + if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && + ConstantBool) { + // br(X && 1) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); + } + + // Emit the LHS as a conditional. If the LHS conditional is false, we + // want to jump to the FalseBlock. + llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); + + ConditionalEvaluation eval(*this); + EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock); + EmitBlock(LHSTrue); + + // Any temporaries created here are conditional. + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + eval.end(*this); + + return; + } + + if (CondBOp->getOpcode() == BO_LOr) { + // If we have "0 || X", simplify the code. "1 || X" would have constant + // folded if the case was simple enough. + bool ConstantBool = false; + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && + !ConstantBool) { + // br(0 || X) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + } + + // If we have "X || 0", simplify the code to use an uncond branch. + // "X || 1" would have been constant folded to 1. + if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && + !ConstantBool) { + // br(X || 0) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); + } + + // Emit the LHS as a conditional. If the LHS conditional is true, we + // want to jump to the TrueBlock. + llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); + + ConditionalEvaluation eval(*this); + EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse); + EmitBlock(LHSFalse); + + // Any temporaries created here are conditional. + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); + eval.end(*this); + + return; + } + } + + if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { + // br(!x, t, f) -> br(x, f, t) + if (CondUOp->getOpcode() == UO_LNot) + return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock); + } + + if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { + // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) + llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); + llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); + + ConditionalEvaluation cond(*this); + EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock); + + cond.begin(*this); + EmitBlock(LHSBlock); + EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock); + cond.end(*this); + + cond.begin(*this); + EmitBlock(RHSBlock); + EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock); + cond.end(*this); + + return; + } + + // Emit the code with the fully general case. + llvm::Value *CondV = EvaluateExprAsBool(Cond); + Builder.CreateCondBr(CondV, TrueBlock, FalseBlock); +} + +/// ErrorUnsupported - Print out an error that codegen doesn't support the +/// specified stmt yet. +void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type, + bool OmitOnError) { + CGM.ErrorUnsupported(S, Type, OmitOnError); +} + +/// emitNonZeroVLAInit - Emit the "zero" initialization of a +/// variable-length array whose elements have a non-zero bit-pattern. +/// +/// \param src - a char* pointing to the bit-pattern for a single +/// base element of the array +/// \param sizeInChars - the total size of the VLA, in chars +/// \param align - the total alignment of the VLA +static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, + llvm::Value *dest, llvm::Value *src, + llvm::Value *sizeInChars) { + std::pair<CharUnits,CharUnits> baseSizeAndAlign + = CGF.getContext().getTypeInfoInChars(baseType); + + CGBuilderTy &Builder = CGF.Builder; + + llvm::Value *baseSizeInChars + = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity()); + + llvm::Type *i8p = Builder.getInt8PtrTy(); + + llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin"); + llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end"); + + llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); + llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); + llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); + + // Make a loop over the VLA. C99 guarantees that the VLA element + // count must be nonzero. + CGF.EmitBlock(loopBB); + + llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur"); + cur->addIncoming(begin, originBB); + + // memcpy the individual element bit-pattern. + Builder.CreateMemCpy(cur, src, baseSizeInChars, + baseSizeAndAlign.second.getQuantity(), + /*volatile*/ false); + + // Go to the next element. + llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next"); + + // Leave if that's the end of the VLA. + llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); + Builder.CreateCondBr(done, contBB, loopBB); + cur->addIncoming(next, loopBB); + + CGF.EmitBlock(contBB); +} + +void +CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { + // Ignore empty classes in C++. + if (getContext().getLangOpts().CPlusPlus) { + if (const RecordType *RT = Ty->getAs<RecordType>()) { + if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) + return; + } + } + + // Cast the dest ptr to the appropriate i8 pointer type. + unsigned DestAS = + cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace(); + llvm::Type *BP = Builder.getInt8PtrTy(DestAS); + if (DestPtr->getType() != BP) + DestPtr = Builder.CreateBitCast(DestPtr, BP); + + // Get size and alignment info for this aggregate. + std::pair<CharUnits, CharUnits> TypeInfo = + getContext().getTypeInfoInChars(Ty); + CharUnits Size = TypeInfo.first; + CharUnits Align = TypeInfo.second; + + llvm::Value *SizeVal; + const VariableArrayType *vla; + + // Don't bother emitting a zero-byte memset. + if (Size.isZero()) { + // But note that getTypeInfo returns 0 for a VLA. + if (const VariableArrayType *vlaType = + dyn_cast_or_null<VariableArrayType>( + getContext().getAsArrayType(Ty))) { + QualType eltType; + llvm::Value *numElts; + llvm::tie(numElts, eltType) = getVLASize(vlaType); + + SizeVal = numElts; + CharUnits eltSize = getContext().getTypeSizeInChars(eltType); + if (!eltSize.isOne()) + SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); + vla = vlaType; + } else { + return; + } + } else { + SizeVal = CGM.getSize(Size); + vla = 0; + } + + // If the type contains a pointer to data member we can't memset it to zero. + // Instead, create a null constant and copy it to the destination. + // TODO: there are other patterns besides zero that we can usefully memset, + // like -1, which happens to be the pattern used by member-pointers. + if (!CGM.getTypes().isZeroInitializable(Ty)) { + // For a VLA, emit a single element, then splat that over the VLA. + if (vla) Ty = getContext().getBaseElementType(vla); + + llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); + + llvm::GlobalVariable *NullVariable = + new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), + /*isConstant=*/true, + llvm::GlobalVariable::PrivateLinkage, + NullConstant, Twine()); + llvm::Value *SrcPtr = + Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()); + + if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); + + // Get and call the appropriate llvm.memcpy overload. + Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false); + return; + } + + // Otherwise, just memset the whole thing to zero. This is legal + // because in LLVM, all default initializers (other than the ones we just + // handled above) are guaranteed to have a bit pattern of all zeros. + Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, + Align.getQuantity(), false); +} + +llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { + // Make sure that there is a block for the indirect goto. + if (IndirectBranch == 0) + GetIndirectGotoBlock(); + + llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); + + // Make sure the indirect branch includes all of the address-taken blocks. + IndirectBranch->addDestination(BB); + return llvm::BlockAddress::get(CurFn, BB); +} + +llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { + // If we already made the indirect branch for indirect goto, return its block. + if (IndirectBranch) return IndirectBranch->getParent(); + + CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto")); + + // Create the PHI node that indirect gotos will add entries to. + llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, + "indirect.goto.dest"); + + // Create the indirect branch instruction. + IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); + return IndirectBranch->getParent(); +} + +/// Computes the length of an array in elements, as well as the base +/// element type and a properly-typed first element pointer. +llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, + QualType &baseType, + llvm::Value *&addr) { + const ArrayType *arrayType = origArrayType; + + // If it's a VLA, we have to load the stored size. Note that + // this is the size of the VLA in bytes, not its size in elements. + llvm::Value *numVLAElements = 0; + if (isa<VariableArrayType>(arrayType)) { + numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first; + + // Walk into all VLAs. This doesn't require changes to addr, + // which has type T* where T is the first non-VLA element type. + do { + QualType elementType = arrayType->getElementType(); + arrayType = getContext().getAsArrayType(elementType); + + // If we only have VLA components, 'addr' requires no adjustment. + if (!arrayType) { + baseType = elementType; + return numVLAElements; + } + } while (isa<VariableArrayType>(arrayType)); + + // We get out here only if we find a constant array type + // inside the VLA. + } + + // We have some number of constant-length arrays, so addr should + // have LLVM type [M x [N x [...]]]*. Build a GEP that walks + // down to the first element of addr. + SmallVector<llvm::Value*, 8> gepIndices; + + // GEP down to the array type. + llvm::ConstantInt *zero = Builder.getInt32(0); + gepIndices.push_back(zero); + + // It's more efficient to calculate the count from the LLVM + // constant-length arrays than to re-evaluate the array bounds. + uint64_t countFromCLAs = 1; + + llvm::ArrayType *llvmArrayType = + cast<llvm::ArrayType>( + cast<llvm::PointerType>(addr->getType())->getElementType()); + while (true) { + assert(isa<ConstantArrayType>(arrayType)); + assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() + == llvmArrayType->getNumElements()); + + gepIndices.push_back(zero); + countFromCLAs *= llvmArrayType->getNumElements(); + + llvmArrayType = + dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); + if (!llvmArrayType) break; + + arrayType = getContext().getAsArrayType(arrayType->getElementType()); + assert(arrayType && "LLVM and Clang types are out-of-synch"); + } + + baseType = arrayType->getElementType(); + + // Create the actual GEP. + addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin"); + + llvm::Value *numElements + = llvm::ConstantInt::get(SizeTy, countFromCLAs); + + // If we had any VLA dimensions, factor them in. + if (numVLAElements) + numElements = Builder.CreateNUWMul(numVLAElements, numElements); + + return numElements; +} + +std::pair<llvm::Value*, QualType> +CodeGenFunction::getVLASize(QualType type) { + const VariableArrayType *vla = getContext().getAsVariableArrayType(type); + assert(vla && "type was not a variable array type!"); + return getVLASize(vla); +} + +std::pair<llvm::Value*, QualType> +CodeGenFunction::getVLASize(const VariableArrayType *type) { + // The number of elements so far; always size_t. + llvm::Value *numElements = 0; + + QualType elementType; + do { + elementType = type->getElementType(); + llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; + assert(vlaSize && "no size for VLA!"); + assert(vlaSize->getType() == SizeTy); + + if (!numElements) { + numElements = vlaSize; + } else { + // It's undefined behavior if this wraps around, so mark it that way. + numElements = Builder.CreateNUWMul(numElements, vlaSize); + } + } while ((type = getContext().getAsVariableArrayType(elementType))); + + return std::pair<llvm::Value*,QualType>(numElements, elementType); +} + +void CodeGenFunction::EmitVariablyModifiedType(QualType type) { + assert(type->isVariablyModifiedType() && + "Must pass variably modified type to EmitVLASizes!"); + + EnsureInsertPoint(); + + // We're going to walk down into the type and look for VLA + // expressions. + do { + assert(type->isVariablyModifiedType()); + + const Type *ty = type.getTypePtr(); + switch (ty->getTypeClass()) { + +#define TYPE(Class, Base) +#define ABSTRACT_TYPE(Class, Base) +#define NON_CANONICAL_TYPE(Class, Base) +#define DEPENDENT_TYPE(Class, Base) case Type::Class: +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) +#include "clang/AST/TypeNodes.def" + llvm_unreachable("unexpected dependent type!"); + + // These types are never variably-modified. + case Type::Builtin: + case Type::Complex: + case Type::Vector: + case Type::ExtVector: + case Type::Record: + case Type::Enum: + case Type::Elaborated: + case Type::TemplateSpecialization: + case Type::ObjCObject: + case Type::ObjCInterface: + case Type::ObjCObjectPointer: + llvm_unreachable("type class is never variably-modified!"); + + case Type::Pointer: + type = cast<PointerType>(ty)->getPointeeType(); + break; + + case Type::BlockPointer: + type = cast<BlockPointerType>(ty)->getPointeeType(); + break; + + case Type::LValueReference: + case Type::RValueReference: + type = cast<ReferenceType>(ty)->getPointeeType(); + break; + + case Type::MemberPointer: + type = cast<MemberPointerType>(ty)->getPointeeType(); + break; + + case Type::ConstantArray: + case Type::IncompleteArray: + // Losing element qualification here is fine. + type = cast<ArrayType>(ty)->getElementType(); + break; + + case Type::VariableArray: { + // Losing element qualification here is fine. + const VariableArrayType *vat = cast<VariableArrayType>(ty); + + // Unknown size indication requires no size computation. + // Otherwise, evaluate and record it. + if (const Expr *size = vat->getSizeExpr()) { + // It's possible that we might have emitted this already, + // e.g. with a typedef and a pointer to it. + llvm::Value *&entry = VLASizeMap[size]; + if (!entry) { + // Always zexting here would be wrong if it weren't + // undefined behavior to have a negative bound. + entry = Builder.CreateIntCast(EmitScalarExpr(size), SizeTy, + /*signed*/ false); + } + } + type = vat->getElementType(); + break; + } + + case Type::FunctionProto: + case Type::FunctionNoProto: + type = cast<FunctionType>(ty)->getResultType(); + break; + + case Type::Paren: + case Type::TypeOf: + case Type::UnaryTransform: + case Type::Attributed: + case Type::SubstTemplateTypeParm: + // Keep walking after single level desugaring. + type = type.getSingleStepDesugaredType(getContext()); + break; + + case Type::Typedef: + case Type::Decltype: + case Type::Auto: + // Stop walking: nothing to do. + return; + + case Type::TypeOfExpr: + // Stop walking: emit typeof expression. + EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); + return; + + case Type::Atomic: + type = cast<AtomicType>(ty)->getValueType(); + break; + } + } while (type->isVariablyModifiedType()); +} + +llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { + if (getContext().getBuiltinVaListType()->isArrayType()) + return EmitScalarExpr(E); + return EmitLValue(E).getAddress(); +} + +void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, + llvm::Constant *Init) { + assert (Init && "Invalid DeclRefExpr initializer!"); + if (CGDebugInfo *Dbg = getDebugInfo()) + Dbg->EmitGlobalVariable(E->getDecl(), Init); +} + +CodeGenFunction::PeepholeProtection +CodeGenFunction::protectFromPeepholes(RValue rvalue) { + // At the moment, the only aggressive peephole we do in IR gen + // is trunc(zext) folding, but if we add more, we can easily + // extend this protection. + + if (!rvalue.isScalar()) return PeepholeProtection(); + llvm::Value *value = rvalue.getScalarVal(); + if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); + + // Just make an extra bitcast. + assert(HaveInsertPoint()); + llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", + Builder.GetInsertBlock()); + + PeepholeProtection protection; + protection.Inst = inst; + return protection; +} + +void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { + if (!protection.Inst) return; + + // In theory, we could try to duplicate the peepholes now, but whatever. + protection.Inst->eraseFromParent(); +} + +llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn, + llvm::Value *AnnotatedVal, + llvm::StringRef AnnotationStr, + SourceLocation Location) { + llvm::Value *Args[4] = { + AnnotatedVal, + Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), + Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), + CGM.EmitAnnotationLineNo(Location) + }; + return Builder.CreateCall(AnnotationFn, Args); +} + +void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { + assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); + // FIXME We create a new bitcast for every annotation because that's what + // llvm-gcc was doing. + for (specific_attr_iterator<AnnotateAttr> + ai = D->specific_attr_begin<AnnotateAttr>(), + ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) + EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), + Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), + (*ai)->getAnnotation(), D->getLocation()); +} + +llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, + llvm::Value *V) { + assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); + llvm::Type *VTy = V->getType(); + llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, + CGM.Int8PtrTy); + + for (specific_attr_iterator<AnnotateAttr> + ai = D->specific_attr_begin<AnnotateAttr>(), + ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) { + // FIXME Always emit the cast inst so we can differentiate between + // annotation on the first field of a struct and annotation on the struct + // itself. + if (VTy != CGM.Int8PtrTy) + V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy)); + V = EmitAnnotationCall(F, V, (*ai)->getAnnotation(), D->getLocation()); + V = Builder.CreateBitCast(V, VTy); + } + + return V; +} |
