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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 | 1683 |
1 files changed, 1683 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..5ca3a78 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp @@ -0,0 +1,1683 @@ +//===--- 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 "CGCUDARuntime.h" +#include "CGCXXABI.h" +#include "CGDebugInfo.h" +#include "CGOpenMPRuntime.h" +#include "CodeGenModule.h" +#include "CodeGenPGO.h" +#include "TargetInfo.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtCXX.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/CodeGen/CGFunctionInfo.h" +#include "clang/Frontend/CodeGenOptions.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Intrinsics.h" +#include "llvm/IR/MDBuilder.h" +#include "llvm/IR/Operator.h" +using namespace clang; +using namespace CodeGen; + +CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) + : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()), + Builder(cgm.getModule().getContext(), llvm::ConstantFolder(), + CGBuilderInserterTy(this)), + CapturedStmtInfo(nullptr), SanOpts(&CGM.getLangOpts().Sanitize), + IsSanitizerScope(false), AutoreleaseResult(false), BlockInfo(nullptr), + BlockPointer(nullptr), LambdaThisCaptureField(nullptr), + NormalCleanupDest(nullptr), NextCleanupDestIndex(1), + FirstBlockInfo(nullptr), EHResumeBlock(nullptr), ExceptionSlot(nullptr), + EHSelectorSlot(nullptr), DebugInfo(CGM.getModuleDebugInfo()), + DisableDebugInfo(false), DidCallStackSave(false), IndirectBranch(nullptr), + PGO(cgm), SwitchInsn(nullptr), SwitchWeights(nullptr), + CaseRangeBlock(nullptr), UnreachableBlock(nullptr), NumReturnExprs(0), + NumSimpleReturnExprs(0), CXXABIThisDecl(nullptr), + CXXABIThisValue(nullptr), CXXThisValue(nullptr), + CXXDefaultInitExprThis(nullptr), CXXStructorImplicitParamDecl(nullptr), + CXXStructorImplicitParamValue(nullptr), OutermostConditional(nullptr), + CurLexicalScope(nullptr), TerminateLandingPad(nullptr), + TerminateHandler(nullptr), TrapBB(nullptr) { + if (!suppressNewContext) + CGM.getCXXABI().getMangleContext().startNewFunction(); + + llvm::FastMathFlags FMF; + if (CGM.getLangOpts().FastMath) + FMF.setUnsafeAlgebra(); + if (CGM.getLangOpts().FiniteMathOnly) { + FMF.setNoNaNs(); + FMF.setNoInfs(); + } + Builder.SetFastMathFlags(FMF); +} + +CodeGenFunction::~CodeGenFunction() { + assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup"); + + // 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); + + if (getLangOpts().OpenMP) { + CGM.getOpenMPRuntime().FunctionFinished(*this); + } +} + + +llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { + return CGM.getTypes().ConvertTypeForMem(T); +} + +llvm::Type *CodeGenFunction::ConvertType(QualType T) { + return CGM.getTypes().ConvertType(T); +} + +TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) { + type = type.getCanonicalType(); + while (true) { + switch (type->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::Auto: + llvm_unreachable("undeduced auto type in IR-generation"); + + // Various scalar types. + 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 TEK_Scalar; + + // Complexes. + case Type::Complex: + return TEK_Complex; + + // Arrays, records, and Objective-C objects. + case Type::ConstantArray: + case Type::IncompleteArray: + case Type::VariableArray: + case Type::Record: + case Type::ObjCObject: + case Type::ObjCInterface: + return TEK_Aggregate; + + // We operate on atomic values according to their underlying type. + case Type::Atomic: + type = cast<AtomicType>(type)->getValueType(); + continue; + } + 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()->user_begin()); + if (BI && BI->isUnconditional() && + BI->getSuccessor(0) == ReturnBlock.getBlock()) { + // Reset insertion point, including debug location, and delete the + // branch. This is really subtle and only works because the next change + // in location will hit the caching in CGDebugInfo::EmitLocation and not + // override this. + 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!"); + + bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0 + && NumSimpleReturnExprs == NumReturnExprs + && ReturnBlock.getBlock()->use_empty(); + // Usually the return expression is evaluated before the cleanup + // code. If the function contains only a simple return statement, + // such as a constant, the location before the cleanup code becomes + // the last useful breakpoint in the function, because the simple + // return expression will be evaluated after the cleanup code. To be + // safe, set the debug location for cleanup code to the location of + // the return statement. Otherwise the cleanup code should be at the + // end of the function's lexical scope. + // + // If there are multiple branches to the return block, the branch + // instructions will get the location of the return statements and + // all will be fine. + if (CGDebugInfo *DI = getDebugInfo()) { + if (OnlySimpleReturnStmts) + DI->EmitLocation(Builder, LastStopPoint); + else + DI->EmitLocation(Builder, EndLoc); + } + + // 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. + bool EmitRetDbgLoc = true; + if (EHStack.stable_begin() != PrologueCleanupDepth) { + PopCleanupBlocks(PrologueCleanupDepth); + + // Make sure the line table doesn't jump back into the body for + // the ret after it's been at EndLoc. + EmitRetDbgLoc = false; + + if (CGDebugInfo *DI = getDebugInfo()) + if (OnlySimpleReturnStmts) + DI->EmitLocation(Builder, EndLoc); + } + + // Emit function epilog (to return). + EmitReturnBlock(); + + if (ShouldInstrumentFunction()) + EmitFunctionInstrumentation("__cyg_profile_func_exit"); + + // Emit debug descriptor for function end. + if (CGDebugInfo *DI = getDebugInfo()) { + DI->EmitFunctionEnd(Builder); + } + + EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc, EndLoc); + 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 = nullptr; + 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(); + + for (SmallVectorImpl<std::pair<llvm::Instruction *, llvm::Value *> >::iterator + I = DeferredReplacements.begin(), + E = DeferredReplacements.end(); + I != E; ++I) { + I->first->replaceAllUsesWith(I->second); + I->first->eraseFromParent(); + } +} + +/// 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"); + + llvm::Value *args[] = { + llvm::ConstantExpr::getBitCast(CurFn, PointerTy), + CallSite + }; + + EmitNounwindRuntimeCall(F, args); +} + +void CodeGenFunction::EmitMCountInstrumentation() { + llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); + + llvm::Constant *MCountFn = + CGM.CreateRuntimeFunction(FTy, getTarget().getMCountName()); + EmitNounwindRuntimeCall(MCountFn); +} + +// OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument +// information in the program executable. The argument information stored +// includes the argument name, its type, the address and access qualifiers used. +static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn, + CodeGenModule &CGM,llvm::LLVMContext &Context, + SmallVector <llvm::Value*, 5> &kernelMDArgs, + CGBuilderTy& Builder, ASTContext &ASTCtx) { + // Create MDNodes that represent the kernel arg metadata. + // Each MDNode is a list in the form of "key", N number of values which is + // the same number of values as their are kernel arguments. + + const PrintingPolicy &Policy = ASTCtx.getPrintingPolicy(); + + // MDNode for the kernel argument address space qualifiers. + SmallVector<llvm::Value*, 8> addressQuals; + addressQuals.push_back(llvm::MDString::get(Context, "kernel_arg_addr_space")); + + // MDNode for the kernel argument access qualifiers (images only). + SmallVector<llvm::Value*, 8> accessQuals; + accessQuals.push_back(llvm::MDString::get(Context, "kernel_arg_access_qual")); + + // MDNode for the kernel argument type names. + SmallVector<llvm::Value*, 8> argTypeNames; + argTypeNames.push_back(llvm::MDString::get(Context, "kernel_arg_type")); + + // MDNode for the kernel argument type qualifiers. + SmallVector<llvm::Value*, 8> argTypeQuals; + argTypeQuals.push_back(llvm::MDString::get(Context, "kernel_arg_type_qual")); + + // MDNode for the kernel argument names. + SmallVector<llvm::Value*, 8> argNames; + argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name")); + + for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) { + const ParmVarDecl *parm = FD->getParamDecl(i); + QualType ty = parm->getType(); + std::string typeQuals; + + if (ty->isPointerType()) { + QualType pointeeTy = ty->getPointeeType(); + + // Get address qualifier. + addressQuals.push_back(Builder.getInt32(ASTCtx.getTargetAddressSpace( + pointeeTy.getAddressSpace()))); + + // Get argument type name. + std::string typeName = + pointeeTy.getUnqualifiedType().getAsString(Policy) + "*"; + + // Turn "unsigned type" to "utype" + std::string::size_type pos = typeName.find("unsigned"); + if (pos != std::string::npos) + typeName.erase(pos+1, 8); + + argTypeNames.push_back(llvm::MDString::get(Context, typeName)); + + // Get argument type qualifiers: + if (ty.isRestrictQualified()) + typeQuals = "restrict"; + if (pointeeTy.isConstQualified() || + (pointeeTy.getAddressSpace() == LangAS::opencl_constant)) + typeQuals += typeQuals.empty() ? "const" : " const"; + if (pointeeTy.isVolatileQualified()) + typeQuals += typeQuals.empty() ? "volatile" : " volatile"; + } else { + uint32_t AddrSpc = 0; + if (ty->isImageType()) + AddrSpc = + CGM.getContext().getTargetAddressSpace(LangAS::opencl_global); + + addressQuals.push_back(Builder.getInt32(AddrSpc)); + + // Get argument type name. + std::string typeName = ty.getUnqualifiedType().getAsString(Policy); + + // Turn "unsigned type" to "utype" + std::string::size_type pos = typeName.find("unsigned"); + if (pos != std::string::npos) + typeName.erase(pos+1, 8); + + argTypeNames.push_back(llvm::MDString::get(Context, typeName)); + + // Get argument type qualifiers: + if (ty.isConstQualified()) + typeQuals = "const"; + if (ty.isVolatileQualified()) + typeQuals += typeQuals.empty() ? "volatile" : " volatile"; + } + + argTypeQuals.push_back(llvm::MDString::get(Context, typeQuals)); + + // Get image access qualifier: + if (ty->isImageType()) { + const OpenCLImageAccessAttr *A = parm->getAttr<OpenCLImageAccessAttr>(); + if (A && A->isWriteOnly()) + accessQuals.push_back(llvm::MDString::get(Context, "write_only")); + else + accessQuals.push_back(llvm::MDString::get(Context, "read_only")); + // FIXME: what about read_write? + } else + accessQuals.push_back(llvm::MDString::get(Context, "none")); + + // Get argument name. + argNames.push_back(llvm::MDString::get(Context, parm->getName())); + } + + kernelMDArgs.push_back(llvm::MDNode::get(Context, addressQuals)); + kernelMDArgs.push_back(llvm::MDNode::get(Context, accessQuals)); + kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeNames)); + kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeQuals)); + kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames)); +} + +void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, + llvm::Function *Fn) +{ + if (!FD->hasAttr<OpenCLKernelAttr>()) + return; + + llvm::LLVMContext &Context = getLLVMContext(); + + SmallVector <llvm::Value*, 5> kernelMDArgs; + kernelMDArgs.push_back(Fn); + + if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata) + GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs, + Builder, getContext()); + + if (const VecTypeHintAttr *A = FD->getAttr<VecTypeHintAttr>()) { + QualType hintQTy = A->getTypeHint(); + const ExtVectorType *hintEltQTy = hintQTy->getAs<ExtVectorType>(); + bool isSignedInteger = + hintQTy->isSignedIntegerType() || + (hintEltQTy && hintEltQTy->getElementType()->isSignedIntegerType()); + llvm::Value *attrMDArgs[] = { + llvm::MDString::get(Context, "vec_type_hint"), + llvm::UndefValue::get(CGM.getTypes().ConvertType(A->getTypeHint())), + llvm::ConstantInt::get( + llvm::IntegerType::get(Context, 32), + llvm::APInt(32, (uint64_t)(isSignedInteger ? 1 : 0))) + }; + kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); + } + + if (const WorkGroupSizeHintAttr *A = FD->getAttr<WorkGroupSizeHintAttr>()) { + llvm::Value *attrMDArgs[] = { + llvm::MDString::get(Context, "work_group_size_hint"), + Builder.getInt32(A->getXDim()), + Builder.getInt32(A->getYDim()), + Builder.getInt32(A->getZDim()) + }; + kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); + } + + if (const ReqdWorkGroupSizeAttr *A = FD->getAttr<ReqdWorkGroupSizeAttr>()) { + llvm::Value *attrMDArgs[] = { + llvm::MDString::get(Context, "reqd_work_group_size"), + Builder.getInt32(A->getXDim()), + Builder.getInt32(A->getYDim()), + Builder.getInt32(A->getZDim()) + }; + kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); + } + + llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs); + llvm::NamedMDNode *OpenCLKernelMetadata = + CGM.getModule().getOrInsertNamedMetadata("opencl.kernels"); + OpenCLKernelMetadata->addOperand(kernelMDNode); +} + +/// Determine whether the function F ends with a return stmt. +static bool endsWithReturn(const Decl* F) { + const Stmt *Body = nullptr; + if (auto *FD = dyn_cast_or_null<FunctionDecl>(F)) + Body = FD->getBody(); + else if (auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(F)) + Body = OMD->getBody(); + + if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) { + auto LastStmt = CS->body_rbegin(); + if (LastStmt != CS->body_rend()) + return isa<ReturnStmt>(*LastStmt); + } + return false; +} + +void CodeGenFunction::StartFunction(GlobalDecl GD, + QualType RetTy, + llvm::Function *Fn, + const CGFunctionInfo &FnInfo, + const FunctionArgList &Args, + SourceLocation Loc, + SourceLocation StartLoc) { + const Decl *D = GD.getDecl(); + + DidCallStackSave = false; + CurCodeDecl = D; + CurFuncDecl = (D ? D->getNonClosureContext() : nullptr); + FnRetTy = RetTy; + CurFn = Fn; + CurFnInfo = &FnInfo; + assert(CurFn->isDeclaration() && "Function already has body?"); + + if (CGM.getSanitizerBlacklist().isIn(*Fn)) + SanOpts = &SanitizerOptions::Disabled; + + // Pass inline keyword to optimizer if it appears explicitly on any + // declaration. Also, in the case of -fno-inline attach NoInline + // attribute to all function that are not marked AlwaysInline. + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { + if (!CGM.getCodeGenOpts().NoInline) { + for (auto RI : FD->redecls()) + if (RI->isInlineSpecified()) { + Fn->addFnAttr(llvm::Attribute::InlineHint); + break; + } + } else if (!FD->hasAttr<AlwaysInlineAttr>()) + Fn->addFnAttr(llvm::Attribute::NoInline); + } + + if (getLangOpts().OpenCL) { + // Add metadata for a kernel function. + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + EmitOpenCLKernelMetadata(FD, Fn); + } + + // If we are checking function types, emit a function type signature as + // prefix data. + if (getLangOpts().CPlusPlus && SanOpts->Function) { + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { + if (llvm::Constant *PrefixSig = + CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) { + llvm::Constant *FTRTTIConst = + CGM.GetAddrOfRTTIDescriptor(FD->getType(), /*ForEH=*/true); + llvm::Constant *PrefixStructElems[] = { PrefixSig, FTRTTIConst }; + llvm::Constant *PrefixStructConst = + llvm::ConstantStruct::getAnon(PrefixStructElems, /*Packed=*/true); + Fn->setPrefixData(PrefixStructConst); + } + } + } + + 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()) { + SmallVector<QualType, 16> ArgTypes; + for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); + i != e; ++i) { + ArgTypes.push_back((*i)->getType()); + } + + QualType FnType = + getContext().getFunctionType(RetTy, ArgTypes, + FunctionProtoType::ExtProtoInfo()); + DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder); + } + + if (ShouldInstrumentFunction()) + EmitFunctionInstrumentation("__cyg_profile_func_enter"); + + if (CGM.getCodeGenOpts().InstrumentForProfiling) + EmitMCountInstrumentation(); + + if (RetTy->isVoidType()) { + // Void type; nothing to return. + ReturnValue = nullptr; + + // Count the implicit return. + if (!endsWithReturn(D)) + ++NumReturnExprs; + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && + !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { + // Indirect aggregate return; emit returned value directly into sret slot. + // This reduces code size, and affects correctness in C++. + auto AI = CurFn->arg_begin(); + if (CurFnInfo->getReturnInfo().isSRetAfterThis()) + ++AI; + ReturnValue = AI; + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca && + !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { + // Load the sret pointer from the argument struct and return into that. + unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex(); + llvm::Function::arg_iterator EI = CurFn->arg_end(); + --EI; + llvm::Value *Addr = Builder.CreateStructGEP(EI, Idx); + ReturnValue = Builder.CreateLoad(Addr, "agg.result"); + } 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 = EmitLValueForLambdaField(LambdaThisCaptureField); + CXXThisValue = EmitLoadOfLValue(ThisLValue, + SourceLocation()).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) { + const VarDecl *VD = *i; + + // Dig out the type as written from ParmVarDecls; it's unclear whether + // the standard (C99 6.9.1p10) requires this, but we're following the + // precedent set by gcc. + QualType Ty; + if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) + Ty = PVD->getOriginalType(); + else + Ty = VD->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 Stmt *Body) { + RegionCounter Cnt = getPGORegionCounter(Body); + Cnt.beginRegion(Builder); + if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body)) + EmitCompoundStmtWithoutScope(*S); + else + EmitStmt(Body); +} + +/// When instrumenting to collect profile data, the counts for some blocks +/// such as switch cases need to not include the fall-through counts, so +/// emit a branch around the instrumentation code. When not instrumenting, +/// this just calls EmitBlock(). +void CodeGenFunction::EmitBlockWithFallThrough(llvm::BasicBlock *BB, + RegionCounter &Cnt) { + llvm::BasicBlock *SkipCountBB = nullptr; + if (HaveInsertPoint() && CGM.getCodeGenOpts().ProfileInstrGenerate) { + // When instrumenting for profiling, the fallthrough to certain + // statements needs to skip over the instrumentation code so that we + // get an accurate count. + SkipCountBB = createBasicBlock("skipcount"); + EmitBranch(SkipCountBB); + } + EmitBlock(BB); + Cnt.beginRegion(Builder, /*AddIncomingFallThrough=*/true); + if (SkipCountBB) + EmitBlock(SkipCountBB); +} + +/// 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(); +} + +static void EmitSizedDeallocationFunction(CodeGenFunction &CGF, + const FunctionDecl *UnsizedDealloc) { + // This is a weak discardable definition of the sized deallocation function. + CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage); + + // Call the unsized deallocation function and forward the first argument + // unchanged. + llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc); + CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin()); +} + +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 (FD->hasAttr<NoDebugAttr>()) + DebugInfo = nullptr; // disable debug info indefinitely for this function + + FunctionArgList Args; + QualType ResTy = FD->getReturnType(); + + CurGD = GD; + const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); + if (MD && MD->isInstance()) { + if (CGM.getCXXABI().HasThisReturn(GD)) + ResTy = MD->getThisType(getContext()); + CGM.getCXXABI().buildThisParam(*this, Args); + } + + for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) + Args.push_back(FD->getParamDecl(i)); + + if (MD && (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD))) + CGM.getCXXABI().addImplicitStructorParams(*this, ResTy, Args); + + SourceRange BodyRange; + if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); + CurEHLocation = BodyRange.getEnd(); + + // Use the location of the start of the function to determine where + // the function definition is located. By default use the location + // of the declaration as the location for the subprogram. A function + // may lack a declaration in the source code if it is created by code + // gen. (examples: _GLOBAL__I_a, __cxx_global_array_dtor, thunk). + SourceLocation Loc = FD->getLocation(); + + // If this is a function specialization then use the pattern body + // as the location for the function. + if (const FunctionDecl *SpecDecl = FD->getTemplateInstantiationPattern()) + if (SpecDecl->hasBody(SpecDecl)) + Loc = SpecDecl->getLocation(); + + // Emit the standard function prologue. + StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin()); + + // Generate the body of the function. + PGO.assignRegionCounters(GD.getDecl(), CurFn); + if (isa<CXXDestructorDecl>(FD)) + EmitDestructorBody(Args); + else if (isa<CXXConstructorDecl>(FD)) + EmitConstructorBody(Args); + else if (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 static invoker function is special, because it forwards or + // clones the body of the function call operator (but is actually static). + EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD)); + } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) && + (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() || + cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) { + // Implicit copy-assignment gets the same special treatment as implicit + // copy-constructors. + emitImplicitAssignmentOperatorBody(Args); + } else if (Stmt *Body = FD->getBody()) { + EmitFunctionBody(Args, Body); + } else if (FunctionDecl *UnsizedDealloc = + FD->getCorrespondingUnsizedGlobalDeallocationFunction()) { + // Global sized deallocation functions get an implicit weak definition if + // they don't have an explicit definition. + EmitSizedDeallocationFunction(*this, UnsizedDealloc); + } else + llvm_unreachable("no definition for emitted function"); + + // C++11 [stmt.return]p2: + // Flowing off the end of a function [...] results in undefined behavior in + // a value-returning function. + // C11 6.9.1p12: + // If the '}' that terminates a function is reached, and the value of the + // function call is used by the caller, the behavior is undefined. + if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && + !FD->getReturnType()->isVoidType() && Builder.GetInsertBlock()) { + if (SanOpts->Return) { + SanitizerScope SanScope(this); + EmitCheck(Builder.getFalse(), "missing_return", + EmitCheckSourceLocation(FD->getLocation()), + ArrayRef<llvm::Value *>(), CRK_Unrecoverable); + } else if (CGM.getCodeGenOpts().OptimizationLevel == 0) + Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap)); + Builder.CreateUnreachable(); + Builder.ClearInsertionPoint(); + } + + // 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); + + PGO.emitInstrumentationData(); + PGO.destroyRegionCounters(); +} + +/// 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) 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) 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::APSInt 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::APSInt &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, + uint64_t TrueCount) { + Cond = Cond->IgnoreParens(); + + if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { + + // Handle X && Y in a condition. + if (CondBOp->getOpcode() == BO_LAnd) { + RegionCounter Cnt = getPGORegionCounter(CondBOp); + + // 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). + Cnt.beginRegion(Builder); + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // 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, + TrueCount); + } + + // 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"); + // The counter tells us how often we evaluate RHS, and all of TrueCount + // can be propagated to that branch. + uint64_t RHSCount = Cnt.getCount(); + + ConditionalEvaluation eval(*this); + EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount); + EmitBlock(LHSTrue); + + // Any temporaries created here are conditional. + Cnt.beginRegion(Builder); + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, TrueCount); + eval.end(*this); + + return; + } + + if (CondBOp->getOpcode() == BO_LOr) { + RegionCounter Cnt = getPGORegionCounter(CondBOp); + + // 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). + Cnt.beginRegion(Builder); + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // 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, + TrueCount); + } + + // 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"); + // We have the count for entry to the RHS and for the whole expression + // being true, so we can divy up True count between the short circuit and + // the RHS. + uint64_t LHSCount = Cnt.getParentCount() - Cnt.getCount(); + uint64_t RHSCount = TrueCount - LHSCount; + + ConditionalEvaluation eval(*this); + EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount); + EmitBlock(LHSFalse); + + // Any temporaries created here are conditional. + Cnt.beginRegion(Builder); + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, RHSCount); + + 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) { + // Negate the count. + uint64_t FalseCount = PGO.getCurrentRegionCount() - TrueCount; + // Negate the condition and swap the destination blocks. + return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock, + FalseCount); + } + } + + 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"); + + RegionCounter Cnt = getPGORegionCounter(CondOp); + ConditionalEvaluation cond(*this); + EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock, Cnt.getCount()); + + // When computing PGO branch weights, we only know the overall count for + // the true block. This code is essentially doing tail duplication of the + // naive code-gen, introducing new edges for which counts are not + // available. Divide the counts proportionally between the LHS and RHS of + // the conditional operator. + uint64_t LHSScaledTrueCount = 0; + if (TrueCount) { + double LHSRatio = Cnt.getCount() / (double) Cnt.getParentCount(); + LHSScaledTrueCount = TrueCount * LHSRatio; + } + + cond.begin(*this); + EmitBlock(LHSBlock); + Cnt.beginRegion(Builder); + EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock, + LHSScaledTrueCount); + cond.end(*this); + + cond.begin(*this); + EmitBlock(RHSBlock); + EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock, + TrueCount - LHSScaledTrueCount); + cond.end(*this); + + return; + } + + if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) { + // Conditional operator handling can give us a throw expression as a + // condition for a case like: + // br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f) + // Fold this to: + // br(c, throw x, br(y, t, f)) + EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false); + return; + } + + // Create branch weights based on the number of times we get here and the + // number of times the condition should be true. + uint64_t CurrentCount = std::max(PGO.getCurrentRegionCount(), TrueCount); + llvm::MDNode *Weights = PGO.createBranchWeights(TrueCount, + CurrentCount - TrueCount); + + // Emit the code with the fully general case. + llvm::Value *CondV = EvaluateExprAsBool(Cond); + Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights); +} + +/// ErrorUnsupported - Print out an error that codegen doesn't support the +/// specified stmt yet. +void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) { + CGM.ErrorUnsupported(S, Type); +} + +/// emitNonZeroVLAInit - Emit the "zero" initialization of a +/// variable-length array whose elements have a non-zero bit-pattern. +/// +/// \param baseType the inner-most element type of the array +/// \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 +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 (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; + std::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 = nullptr; + } + + // 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) + 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 = nullptr; + 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); + + uint64_t countFromCLAs = 1; + QualType eltType; + + llvm::ArrayType *llvmArrayType = + dyn_cast<llvm::ArrayType>( + cast<llvm::PointerType>(addr->getType())->getElementType()); + while (llvmArrayType) { + assert(isa<ConstantArrayType>(arrayType)); + assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() + == llvmArrayType->getNumElements()); + + gepIndices.push_back(zero); + countFromCLAs *= llvmArrayType->getNumElements(); + eltType = arrayType->getElementType(); + + llvmArrayType = + dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); + arrayType = getContext().getAsArrayType(arrayType->getElementType()); + assert((!llvmArrayType || arrayType) && + "LLVM and Clang types are out-of-synch"); + } + + if (arrayType) { + // From this point onwards, the Clang array type has been emitted + // as some other type (probably a packed struct). Compute the array + // size, and just emit the 'begin' expression as a bitcast. + while (arrayType) { + countFromCLAs *= + cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); + eltType = arrayType->getElementType(); + arrayType = getContext().getAsArrayType(eltType); + } + + unsigned AddressSpace = addr->getType()->getPointerAddressSpace(); + llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace); + addr = Builder.CreateBitCast(addr, BaseType, "array.begin"); + } else { + // Create the actual GEP. + addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin"); + } + + baseType = eltType; + + 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 = nullptr; + + 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. + // FIXME: Teach -fsanitize=undefined to trap this. + 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::Adjusted: + type = cast<AdjustedType>(ty)->getAdjustedType(); + break; + + case Type::Decayed: + type = cast<DecayedType>(ty)->getPointeeType(); + break; + + 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) { + llvm::Value *Size = EmitScalarExpr(size); + + // C11 6.7.6.2p5: + // If the size is an expression that is not an integer constant + // expression [...] each time it is evaluated it shall have a value + // greater than zero. + if (SanOpts->VLABound && + size->getType()->isSignedIntegerType()) { + SanitizerScope SanScope(this); + llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); + llvm::Constant *StaticArgs[] = { + EmitCheckSourceLocation(size->getLocStart()), + EmitCheckTypeDescriptor(size->getType()) + }; + EmitCheck(Builder.CreateICmpSGT(Size, Zero), + "vla_bound_not_positive", StaticArgs, Size, + CRK_Recoverable); + } + + // Always zexting here would be wrong if it weren't + // undefined behavior to have a negative bound. + entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); + } + } + type = vat->getElementType(); + break; + } + + case Type::FunctionProto: + case Type::FunctionNoProto: + type = cast<FunctionType>(ty)->getReturnType(); + break; + + case Type::Paren: + case Type::TypeOf: + case Type::UnaryTransform: + case Type::Attributed: + case Type::SubstTemplateTypeParm: + case Type::PackExpansion: + // 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()) + if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) + 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, + 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 (const auto *I : D->specific_attrs<AnnotateAttr>()) + EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), + Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), + I->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 (const auto *I : D->specific_attrs<AnnotateAttr>()) { + // 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, I->getAnnotation(), D->getLocation()); + V = Builder.CreateBitCast(V, VTy); + } + + return V; +} + +CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { } + +CodeGenFunction::SanitizerScope::SanitizerScope(CodeGenFunction *CGF) + : CGF(CGF) { + assert(!CGF->IsSanitizerScope); + CGF->IsSanitizerScope = true; +} + +CodeGenFunction::SanitizerScope::~SanitizerScope() { + CGF->IsSanitizerScope = false; +} + +void CodeGenFunction::InsertHelper(llvm::Instruction *I, + const llvm::Twine &Name, + llvm::BasicBlock *BB, + llvm::BasicBlock::iterator InsertPt) const { + LoopStack.InsertHelper(I); + if (IsSanitizerScope) { + I->setMetadata( + CGM.getModule().getMDKindID("nosanitize"), + llvm::MDNode::get(CGM.getLLVMContext(), ArrayRef<llvm::Value *>())); + } +} + +template <bool PreserveNames> +void CGBuilderInserter<PreserveNames>::InsertHelper( + llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB, + llvm::BasicBlock::iterator InsertPt) const { + llvm::IRBuilderDefaultInserter<PreserveNames>::InsertHelper(I, Name, BB, + InsertPt); + if (CGF) + CGF->InsertHelper(I, Name, BB, InsertPt); +} + +#ifdef NDEBUG +#define PreserveNames false +#else +#define PreserveNames true +#endif +template void CGBuilderInserter<PreserveNames>::InsertHelper( + llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB, + llvm::BasicBlock::iterator InsertPt) const; +#undef PreserveNames |
