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llvm/llvm-project/clang/refs/heads/main/./lib/CodeGen/CGDecl.cpp
blob: 5b0afc5823a91e20aff0082af69293c016bf7dc8 [file] [edit]
//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Decl nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CGBlocks.h"
#include "CGCXXABI.h"
#include "CGCleanup.h"
#include "CGDebugInfo.h"
#include "CGOpenCLRuntime.h"
#include "CGOpenMPRuntime.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "CodeGenPGO.h"
#include "ConstantEmitter.h"
#include "EHScopeStack.h"
#include "PatternInit.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclOpenACC.h"
#include "clang/AST/DeclOpenMP.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/Sema/Sema.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include <optional>
using namespace clang;
using namespace CodeGen;
static_assert(clang::Sema::MaximumAlignment <= llvm::Value::MaximumAlignment,
"Clang max alignment greater than what LLVM supports?");
void CodeGenFunction::EmitDecl(const Decl &D, bool EvaluateConditionDecl) {
switch (D.getKind()) {
case Decl::BuiltinTemplate:
case Decl::TranslationUnit:
case Decl::ExternCContext:
case Decl::Namespace:
case Decl::UnresolvedUsingTypename:
case Decl::ClassTemplateSpecialization:
case Decl::ClassTemplatePartialSpecialization:
case Decl::VarTemplateSpecialization:
case Decl::VarTemplatePartialSpecialization:
case Decl::TemplateTypeParm:
case Decl::UnresolvedUsingValue:
case Decl::NonTypeTemplateParm:
case Decl::CXXDeductionGuide:
case Decl::CXXMethod:
case Decl::CXXConstructor:
case Decl::CXXDestructor:
case Decl::CXXConversion:
case Decl::Field:
case Decl::MSProperty:
case Decl::IndirectField:
case Decl::ObjCIvar:
case Decl::ObjCAtDefsField:
case Decl::ParmVar:
case Decl::ImplicitParam:
case Decl::ClassTemplate:
case Decl::VarTemplate:
case Decl::FunctionTemplate:
case Decl::TypeAliasTemplate:
case Decl::TemplateTemplateParm:
case Decl::ObjCMethod:
case Decl::ObjCCategory:
case Decl::ObjCProtocol:
case Decl::ObjCInterface:
case Decl::ObjCCategoryImpl:
case Decl::ObjCImplementation:
case Decl::ObjCProperty:
case Decl::ObjCCompatibleAlias:
case Decl::PragmaComment:
case Decl::PragmaDetectMismatch:
case Decl::AccessSpec:
case Decl::LinkageSpec:
case Decl::Export:
case Decl::ObjCPropertyImpl:
case Decl::FileScopeAsm:
case Decl::TopLevelStmt:
case Decl::Friend:
case Decl::FriendTemplate:
case Decl::Block:
case Decl::OutlinedFunction:
case Decl::Captured:
case Decl::UsingShadow:
case Decl::ConstructorUsingShadow:
case Decl::ObjCTypeParam:
case Decl::Binding:
case Decl::UnresolvedUsingIfExists:
case Decl::HLSLBuffer:
case Decl::HLSLRootSignature:
llvm_unreachable("Declaration should not be in declstmts!");
case Decl::Record: // struct/union/class X;
case Decl::CXXRecord: // struct/union/class X; [C++]
if (CGDebugInfo *DI = getDebugInfo())
if (cast<RecordDecl>(D).getDefinition())
DI->EmitAndRetainType(
getContext().getCanonicalTagType(cast<RecordDecl>(&D)));
return;
case Decl::Enum: // enum X;
if (CGDebugInfo *DI = getDebugInfo())
if (cast<EnumDecl>(D).getDefinition())
DI->EmitAndRetainType(
getContext().getCanonicalTagType(cast<EnumDecl>(&D)));
return;
case Decl::Function: // void X();
case Decl::EnumConstant: // enum ? { X = ? }
case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
case Decl::ExplicitInstantiation:
case Decl::Label: // __label__ x;
case Decl::Import:
case Decl::MSGuid: // __declspec(uuid("..."))
case Decl::UnnamedGlobalConstant:
case Decl::TemplateParamObject:
case Decl::OMPThreadPrivate:
case Decl::OMPGroupPrivate:
case Decl::OMPAllocate:
case Decl::OMPCapturedExpr:
case Decl::OMPRequires:
case Decl::Empty:
case Decl::Concept:
case Decl::ImplicitConceptSpecialization:
case Decl::LifetimeExtendedTemporary:
case Decl::RequiresExprBody:
// None of these decls require codegen support.
return;
case Decl::CXXExpansionStmt: {
const auto *ESD = cast<CXXExpansionStmtDecl>(&D);
assert(ESD->getInstantiations() && "expansion statement not expanded?");
EmitStmt(ESD->getInstantiations());
return;
}
case Decl::NamespaceAlias:
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
return;
case Decl::Using: // using X; [C++]
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitUsingDecl(cast<UsingDecl>(D));
return;
case Decl::UsingEnum: // using enum X; [C++]
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitUsingEnumDecl(cast<UsingEnumDecl>(D));
return;
case Decl::UsingPack:
for (auto *Using : cast<UsingPackDecl>(D).expansions())
EmitDecl(*Using, /*EvaluateConditionDecl=*/EvaluateConditionDecl);
return;
case Decl::UsingDirective: // using namespace X; [C++]
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));
return;
case Decl::Var:
case Decl::Decomposition: {
const VarDecl &VD = cast<VarDecl>(D);
assert(VD.isLocalVarDecl() &&
"Should not see file-scope variables inside a function!");
EmitVarDecl(VD);
if (EvaluateConditionDecl)
MaybeEmitDeferredVarDeclInit(&VD);
return;
}
case Decl::OMPDeclareReduction:
return CGM.EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(&D), this);
case Decl::OMPDeclareMapper:
return CGM.EmitOMPDeclareMapper(cast<OMPDeclareMapperDecl>(&D), this);
case Decl::OpenACCDeclare:
return CGM.EmitOpenACCDeclare(cast<OpenACCDeclareDecl>(&D), this);
case Decl::OpenACCRoutine:
return CGM.EmitOpenACCRoutine(cast<OpenACCRoutineDecl>(&D), this);
case Decl::Typedef: // typedef int X;
case Decl::TypeAlias: { // using X = int; [C++0x]
QualType Ty = cast<TypedefNameDecl>(D).getUnderlyingType();
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitAndRetainType(Ty);
if (Ty->isVariablyModifiedType())
EmitVariablyModifiedType(Ty);
return;
}
}
}
/// EmitVarDecl - This method handles emission of any variable declaration
/// inside a function, including static vars etc.
void CodeGenFunction::EmitVarDecl(const VarDecl &D) {
if (D.hasExternalStorage())
// Don't emit it now, allow it to be emitted lazily on its first use.
return;
// Some function-scope variable does not have static storage but still
// needs to be emitted like a static variable, e.g. a function-scope
// variable in constant address space in OpenCL.
if (D.getStorageDuration() != SD_Automatic) {
// Static sampler variables translated to function calls.
if (D.getType()->isSamplerT())
return;
llvm::GlobalValue::LinkageTypes Linkage =
CGM.getLLVMLinkageVarDefinition(&D);
// FIXME: We need to force the emission/use of a guard variable for
// some variables even if we can constant-evaluate them because
// we can't guarantee every translation unit will constant-evaluate them.
return EmitStaticVarDecl(D, Linkage);
}
if (D.getType().getAddressSpace() == LangAS::opencl_local)
return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
assert(D.hasLocalStorage());
return EmitAutoVarDecl(D);
}
static std::string getStaticDeclName(CodeGenModule &CGM, const VarDecl &D) {
if (CGM.getLangOpts().CPlusPlus)
return CGM.getMangledName(&D).str();
// If this isn't C++, we don't need a mangled name, just a pretty one.
assert(!D.isExternallyVisible() && "name shouldn't matter");
std::string ContextName;
const DeclContext *DC = D.getDeclContext();
if (auto *CD = dyn_cast<CapturedDecl>(DC))
DC = cast<DeclContext>(CD->getNonClosureContext());
if (const auto *FD = dyn_cast<FunctionDecl>(DC))
ContextName = std::string(CGM.getMangledName(FD));
else if (const auto *BD = dyn_cast<BlockDecl>(DC))
ContextName = std::string(CGM.getBlockMangledName(GlobalDecl(), BD));
else if (const auto *OMD = dyn_cast<ObjCMethodDecl>(DC))
ContextName = OMD->getSelector().getAsString();
else
llvm_unreachable("Unknown context for static var decl");
ContextName += "." + D.getNameAsString();
return ContextName;
}
llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
const VarDecl &D, llvm::GlobalValue::LinkageTypes Linkage) {
// In general, we don't always emit static var decls once before we reference
// them. It is possible to reference them before emitting the function that
// contains them, and it is possible to emit the containing function multiple
// times.
if (llvm::Constant *ExistingGV = StaticLocalDeclMap[&D])
return ExistingGV;
QualType Ty = D.getType();
assert(Ty->isConstantSizeType() && "VLAs can't be static");
// Use the label if the variable is renamed with the asm-label extension.
std::string Name;
if (D.hasAttr<AsmLabelAttr>())
Name = std::string(getMangledName(&D));
else
Name = getStaticDeclName(*this, D);
llvm::Type *LTy = getTypes().ConvertTypeForMem(Ty);
LangAS AS = GetGlobalVarAddressSpace(&D);
unsigned TargetAS = getContext().getTargetAddressSpace(AS);
// OpenCL variables in local address space and CUDA shared
// variables cannot have an initializer.
llvm::Constant *Init = nullptr;
if (Ty.getAddressSpace() == LangAS::opencl_local ||
D.hasAttr<CUDASharedAttr>() || D.hasAttr<LoaderUninitializedAttr>())
Init = llvm::UndefValue::get(LTy);
else
Init = EmitNullConstant(Ty);
llvm::GlobalVariable *GV = new llvm::GlobalVariable(
getModule(), LTy, Ty.isConstant(getContext()), Linkage, Init, Name,
nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
GV->setAlignment(getContext().getDeclAlign(&D).getAsAlign());
if (supportsCOMDAT() && GV->isWeakForLinker())
GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
if (D.getTLSKind())
setTLSMode(GV, D);
setGVProperties(GV, &D);
getTargetCodeGenInfo().setTargetAttributes(cast<Decl>(&D), GV, *this);
// Make sure the result is of the correct type.
LangAS ExpectedAS = Ty.getAddressSpace();
llvm::Constant *Addr = GV;
if (AS != ExpectedAS && D.getTLSKind() == VarDecl::TLS_None) {
Addr = performAddrSpaceCast(
GV,
llvm::PointerType::get(getLLVMContext(),
getContext().getTargetAddressSpace(ExpectedAS)));
}
setStaticLocalDeclAddress(&D, Addr);
// Ensure that the static local gets initialized by making sure the parent
// function gets emitted eventually.
const Decl *DC = cast<Decl>(D.getDeclContext());
// We can't name blocks or captured statements directly, so try to emit their
// parents.
if (isa<BlockDecl>(DC) || isa<CapturedDecl>(DC)) {
DC = DC->getNonClosureContext();
// FIXME: Ensure that global blocks get emitted.
if (!DC)
return Addr;
}
GlobalDecl GD;
if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
GD = GlobalDecl(CD, Ctor_Base);
else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
GD = GlobalDecl(DD, Dtor_Base);
else if (const auto *FD = dyn_cast<FunctionDecl>(DC))
GD = GlobalDecl(FD);
else {
// Don't do anything for Obj-C method decls or global closures. We should
// never defer them.
assert(isa<ObjCMethodDecl>(DC) && "unexpected parent code decl");
}
if (GD.getDecl()) {
// Disable emission of the parent function for the OpenMP device codegen.
CGOpenMPRuntime::DisableAutoDeclareTargetRAII NoDeclTarget(*this);
(void)GetAddrOfGlobal(GD);
}
return Addr;
}
/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
/// global variable that has already been created for it. If the initializer
/// has a different type than GV does, this may free GV and return a different
/// one. Otherwise it just returns GV.
llvm::GlobalVariable *
CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
llvm::GlobalVariable *GV) {
ConstantEmitter emitter(*this);
llvm::Constant *Init = emitter.tryEmitForInitializer(D);
// If constant emission failed, then this should be a C++ static
// initializer.
if (!Init) {
if (!getLangOpts().CPlusPlus)
CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
else if (D.hasFlexibleArrayInit(getContext()))
CGM.ErrorUnsupported(D.getInit(), "flexible array initializer");
else if (HaveInsertPoint()) {
// Since we have a static initializer, this global variable can't
// be constant.
GV->setConstant(false);
EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
}
return GV;
}
PGO->markStmtMaybeUsed(D.getInit()); // FIXME: Too lazy
#ifndef NDEBUG
CharUnits VarSize = CGM.getContext().getTypeSizeInChars(D.getType()) +
D.getFlexibleArrayInitChars(getContext());
CharUnits CstSize = CharUnits::fromQuantity(
CGM.getDataLayout().getTypeAllocSize(Init->getType()));
assert(VarSize == CstSize && "Emitted constant has unexpected size");
#endif
bool NeedsDtor =
D.needsDestruction(getContext()) == QualType::DK_cxx_destructor;
GV->setConstant(
D.getType().isConstantStorage(getContext(), true, !NeedsDtor));
GV->replaceInitializer(Init);
emitter.finalize(GV);
if (NeedsDtor && HaveInsertPoint()) {
// We have a constant initializer, but a nontrivial destructor. We still
// need to perform a guarded "initialization" in order to register the
// destructor.
EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
}
return GV;
}
void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
llvm::GlobalValue::LinkageTypes Linkage) {
// Check to see if we already have a global variable for this
// declaration. This can happen when double-emitting function
// bodies, e.g. with complete and base constructors.
llvm::Constant *addr = CGM.getOrCreateStaticVarDecl(D, Linkage);
CharUnits alignment = getContext().getDeclAlign(&D);
// Store into LocalDeclMap before generating initializer to handle
// circular references.
llvm::Type *elemTy = ConvertTypeForMem(D.getType());
setAddrOfLocalVar(&D, Address(addr, elemTy, alignment));
// We can't have a VLA here, but we can have a pointer to a VLA,
// even though that doesn't really make any sense.
// Make sure to evaluate VLA bounds now so that we have them for later.
if (D.getType()->isVariablyModifiedType())
EmitVariablyModifiedType(D.getType());
// Save the type in case adding the initializer forces a type change.
llvm::Type *expectedType = addr->getType();
llvm::GlobalVariable *var =
cast<llvm::GlobalVariable>(addr->stripPointerCasts());
// CUDA's local and local static __shared__ variables should not
// have any non-empty initializers. This is ensured by Sema.
// Whatever initializer such variable may have when it gets here is
// a no-op and should not be emitted.
bool isCudaSharedVar = getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
D.hasAttr<CUDASharedAttr>();
// If this value has an initializer, emit it.
if (D.getInit() && !isCudaSharedVar) {
ApplyAtomGroup Grp(getDebugInfo());
var = AddInitializerToStaticVarDecl(D, var);
}
var->setAlignment(alignment.getAsAlign());
if (D.hasAttr<AnnotateAttr>())
CGM.AddGlobalAnnotations(&D, var);
if (auto *SA = D.getAttr<PragmaClangBSSSectionAttr>())
var->addAttribute("bss-section", SA->getName());
if (auto *SA = D.getAttr<PragmaClangDataSectionAttr>())
var->addAttribute("data-section", SA->getName());
if (auto *SA = D.getAttr<PragmaClangRodataSectionAttr>())
var->addAttribute("rodata-section", SA->getName());
if (auto *SA = D.getAttr<PragmaClangRelroSectionAttr>())
var->addAttribute("relro-section", SA->getName());
if (const SectionAttr *SA = D.getAttr<SectionAttr>())
var->setSection(SA->getName());
if (D.hasAttr<RetainAttr>())
CGM.addUsedGlobal(var);
else if (D.hasAttr<UsedAttr>())
CGM.addUsedOrCompilerUsedGlobal(var);
if (CGM.getCodeGenOpts().KeepPersistentStorageVariables)
CGM.addUsedOrCompilerUsedGlobal(var);
// We may have to cast the constant because of the initializer
// mismatch above.
//
// FIXME: It is really dangerous to store this in the map; if anyone
// RAUW's the GV uses of this constant will be invalid.
llvm::Constant *castedAddr =
llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(var, expectedType);
LocalDeclMap.find(&D)->second = Address(castedAddr, elemTy, alignment);
CGM.setStaticLocalDeclAddress(&D, castedAddr);
CGM.getSanitizerMetadata()->reportGlobal(var, D);
// Emit global variable debug descriptor for static vars.
CGDebugInfo *DI = getDebugInfo();
if (DI && CGM.getCodeGenOpts().hasReducedDebugInfo()) {
DI->setLocation(D.getLocation());
DI->EmitGlobalVariable(var, &D);
}
}
namespace {
struct DestroyObject final : EHScopeStack::Cleanup {
DestroyObject(Address addr, QualType type,
CodeGenFunction::Destroyer *destroyer,
bool useEHCleanupForArray)
: addr(addr), type(type), destroyer(destroyer),
useEHCleanupForArray(useEHCleanupForArray) {}
Address addr;
QualType type;
CodeGenFunction::Destroyer *destroyer;
bool useEHCleanupForArray;
void Emit(CodeGenFunction &CGF, Flags flags) override {
// Don't use an EH cleanup recursively from an EH cleanup.
bool useEHCleanupForArray =
flags.isForNormalCleanup() && this->useEHCleanupForArray;
CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
}
};
template <class Derived>
struct DestroyNRVOVariable : EHScopeStack::Cleanup {
DestroyNRVOVariable(Address addr, QualType type, llvm::Value *NRVOFlag)
: NRVOFlag(NRVOFlag), Loc(addr), Ty(type) {}
llvm::Value *NRVOFlag;
Address Loc;
QualType Ty;
void Emit(CodeGenFunction &CGF, Flags flags) override {
// Along the exceptions path we always execute the dtor.
bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
llvm::BasicBlock *SkipDtorBB = nullptr;
if (NRVO) {
// If we exited via NRVO, we skip the destructor call.
llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
llvm::Value *DidNRVO =
CGF.Builder.CreateFlagLoad(NRVOFlag, "nrvo.val");
CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
CGF.EmitBlock(RunDtorBB);
}
static_cast<Derived *>(this)->emitDestructorCall(CGF);
if (NRVO) CGF.EmitBlock(SkipDtorBB);
}
virtual ~DestroyNRVOVariable() = default;
};
struct DestroyNRVOVariableCXX final
: DestroyNRVOVariable<DestroyNRVOVariableCXX> {
DestroyNRVOVariableCXX(Address addr, QualType type,
const CXXDestructorDecl *Dtor, llvm::Value *NRVOFlag)
: DestroyNRVOVariable<DestroyNRVOVariableCXX>(addr, type, NRVOFlag),
Dtor(Dtor) {}
const CXXDestructorDecl *Dtor;
void emitDestructorCall(CodeGenFunction &CGF) {
CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
/*ForVirtualBase=*/false,
/*Delegating=*/false, Loc, Ty);
}
};
struct DestroyNRVOVariableC final
: DestroyNRVOVariable<DestroyNRVOVariableC> {
DestroyNRVOVariableC(Address addr, llvm::Value *NRVOFlag, QualType Ty)
: DestroyNRVOVariable<DestroyNRVOVariableC>(addr, Ty, NRVOFlag) {}
void emitDestructorCall(CodeGenFunction &CGF) {
CGF.destroyNonTrivialCStruct(CGF, Loc, Ty);
}
};
struct CallStackRestore final : EHScopeStack::Cleanup {
Address Stack;
CallStackRestore(Address Stack) : Stack(Stack) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
llvm::Value *V = CGF.Builder.CreateLoad(Stack);
CGF.Builder.CreateStackRestore(V);
}
};
struct KmpcAllocFree final : EHScopeStack::Cleanup {
std::pair<llvm::Value *, llvm::Value *> AddrSizePair;
KmpcAllocFree(const std::pair<llvm::Value *, llvm::Value *> &AddrSizePair)
: AddrSizePair(AddrSizePair) {}
void Emit(CodeGenFunction &CGF, Flags EmissionFlags) override {
auto &RT = CGF.CGM.getOpenMPRuntime();
RT.getKmpcFreeShared(CGF, AddrSizePair);
}
};
struct ExtendGCLifetime final : EHScopeStack::Cleanup {
const VarDecl &Var;
ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
// Compute the address of the local variable, in case it's a
// byref or something.
DeclRefExpr DRE(CGF.getContext(), const_cast<VarDecl *>(&Var), false,
Var.getType(), VK_LValue, SourceLocation());
llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE),
SourceLocation());
CGF.EmitExtendGCLifetime(value);
}
};
struct CallCleanupFunction final : EHScopeStack::Cleanup {
llvm::Constant *CleanupFn;
const CGFunctionInfo &FnInfo;
const VarDecl &Var;
const CleanupAttr *Attribute;
CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
const VarDecl *Var, const CleanupAttr *Attr)
: CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var), Attribute(Attr) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
DeclRefExpr DRE(CGF.getContext(), const_cast<VarDecl *>(&Var), false,
Var.getType(), VK_LValue, SourceLocation());
// Compute the address of the local variable, in case it's a byref
// or something.
llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getPointer(CGF);
// In some cases, the type of the function argument will be different from
// the type of the pointer. An example of this is
// void f(void* arg);
// __attribute__((cleanup(f))) void *g;
//
// To fix this we insert a bitcast here.
QualType ArgTy = FnInfo.arg_begin()->type;
llvm::Value *Arg =
CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
CallArgList Args;
Args.add(RValue::get(Arg),
CGF.getContext().getPointerType(Var.getType()));
GlobalDecl GD = GlobalDecl(Attribute->getFunctionDecl());
auto Callee = CGCallee::forDirect(CleanupFn, CGCalleeInfo(GD));
CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args,
/*callOrInvoke*/ nullptr, /*IsMustTail*/ false,
Attribute->getLoc());
}
};
} // end anonymous namespace
/// EmitAutoVarWithLifetime - Does the setup required for an automatic
/// variable with lifetime.
static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
Address addr,
Qualifiers::ObjCLifetime lifetime) {
switch (lifetime) {
case Qualifiers::OCL_None:
llvm_unreachable("present but none");
case Qualifiers::OCL_ExplicitNone:
// nothing to do
break;
case Qualifiers::OCL_Strong: {
CodeGenFunction::Destroyer *destroyer =
(var.hasAttr<ObjCPreciseLifetimeAttr>()
? CodeGenFunction::destroyARCStrongPrecise
: CodeGenFunction::destroyARCStrongImprecise);
CleanupKind cleanupKind = CGF.getARCCleanupKind();
CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
cleanupKind & EHCleanup);
break;
}
case Qualifiers::OCL_Autoreleasing:
// nothing to do
break;
case Qualifiers::OCL_Weak:
// __weak objects always get EH cleanups; otherwise, exceptions
// could cause really nasty crashes instead of mere leaks.
CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
CodeGenFunction::destroyARCWeak,
/*useEHCleanup*/ true);
break;
}
}
static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
if (const Expr *e = dyn_cast<Expr>(s)) {
// Skip the most common kinds of expressions that make
// hierarchy-walking expensive.
s = e = e->IgnoreParenCasts();
if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
return (ref->getDecl() == &var);
if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
const BlockDecl *block = be->getBlockDecl();
for (const auto &I : block->captures()) {
if (I.getVariable() == &var)
return true;
}
}
}
for (const Stmt *SubStmt : s->children())
// SubStmt might be null; as in missing decl or conditional of an if-stmt.
if (SubStmt && isAccessedBy(var, SubStmt))
return true;
return false;
}
static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
if (!decl) return false;
if (!isa<VarDecl>(decl)) return false;
const VarDecl *var = cast<VarDecl>(decl);
return isAccessedBy(*var, e);
}
static bool tryEmitARCCopyWeakInit(CodeGenFunction &CGF,
const LValue &destLV, const Expr *init) {
bool needsCast = false;
while (auto castExpr = dyn_cast<CastExpr>(init->IgnoreParens())) {
switch (castExpr->getCastKind()) {
// Look through casts that don't require representation changes.
case CK_NoOp:
case CK_BitCast:
case CK_BlockPointerToObjCPointerCast:
needsCast = true;
break;
// If we find an l-value to r-value cast from a __weak variable,
// emit this operation as a copy or move.
case CK_LValueToRValue: {
const Expr *srcExpr = castExpr->getSubExpr();
if (srcExpr->getType().getObjCLifetime() != Qualifiers::OCL_Weak)
return false;
// Emit the source l-value.
LValue srcLV = CGF.EmitLValue(srcExpr);
// Handle a formal type change to avoid asserting.
auto srcAddr = srcLV.getAddress();
if (needsCast) {
srcAddr = srcAddr.withElementType(destLV.getAddress().getElementType());
}
// If it was an l-value, use objc_copyWeak.
if (srcExpr->isLValue()) {
CGF.EmitARCCopyWeak(destLV.getAddress(), srcAddr);
} else {
assert(srcExpr->isXValue());
CGF.EmitARCMoveWeak(destLV.getAddress(), srcAddr);
}
return true;
}
// Stop at anything else.
default:
return false;
}
init = castExpr->getSubExpr();
}
return false;
}
static void drillIntoBlockVariable(CodeGenFunction &CGF,
LValue &lvalue,
const VarDecl *var) {
lvalue.setAddress(CGF.emitBlockByrefAddress(lvalue.getAddress(), var));
}
void CodeGenFunction::EmitNullabilityCheck(LValue LHS, llvm::Value *RHS,
SourceLocation Loc) {
if (!SanOpts.has(SanitizerKind::NullabilityAssign))
return;
auto Nullability = LHS.getType()->getNullability();
if (!Nullability || *Nullability != NullabilityKind::NonNull)
return;
// Check if the right hand side of the assignment is nonnull, if the left
// hand side must be nonnull.
auto CheckOrdinal = SanitizerKind::SO_NullabilityAssign;
auto CheckHandler = SanitizerHandler::TypeMismatch;
SanitizerDebugLocation SanScope(this, {CheckOrdinal}, CheckHandler);
llvm::Value *IsNotNull;
if (auto *MPT = LHS.getType()->getAs<MemberPointerType>())
IsNotNull = CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, RHS, MPT);
else
IsNotNull = Builder.CreateIsNotNull(RHS);
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(LHS.getType()),
llvm::ConstantInt::get(Int8Ty, 0), // The LogAlignment info is unused.
llvm::ConstantInt::get(Int8Ty, TCK_NonnullAssign)};
EmitCheck({{IsNotNull, CheckOrdinal}}, CheckHandler, StaticData, RHS);
}
void CodeGenFunction::EmitScalarInit(const Expr *init, const ValueDecl *D,
LValue lvalue, bool capturedByInit) {
Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
if (!lifetime) {
llvm::Value *Value;
if (PointerAuthQualifier PtrAuth = lvalue.getQuals().getPointerAuth()) {
Value = EmitPointerAuthQualify(PtrAuth, init, lvalue.getAddress());
lvalue.getQuals().removePointerAuth();
} else {
Value = EmitScalarExpr(init);
}
if (capturedByInit)
drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
EmitNullabilityCheck(lvalue, Value, init->getExprLoc());
EmitStoreThroughLValue(RValue::get(Value), lvalue, true);
return;
}
if (const CXXDefaultInitExpr *DIE = dyn_cast<CXXDefaultInitExpr>(init))
init = DIE->getExpr();
// If we're emitting a value with lifetime, we have to do the
// initialization *before* we leave the cleanup scopes.
if (auto *EWC = dyn_cast<ExprWithCleanups>(init)) {
CodeGenFunction::RunCleanupsScope Scope(*this);
return EmitScalarInit(EWC->getSubExpr(), D, lvalue, capturedByInit);
}
// We have to maintain the illusion that the variable is
// zero-initialized. If the variable might be accessed in its
// initializer, zero-initialize before running the initializer, then
// actually perform the initialization with an assign.
bool accessedByInit = false;
if (lifetime != Qualifiers::OCL_ExplicitNone)
accessedByInit = (capturedByInit || isAccessedBy(D, init));
if (accessedByInit) {
LValue tempLV = lvalue;
// Drill down to the __block object if necessary.
if (capturedByInit) {
// We can use a simple GEP for this because it can't have been
// moved yet.
tempLV.setAddress(emitBlockByrefAddress(tempLV.getAddress(),
cast<VarDecl>(D),
/*follow*/ false));
}
auto ty = cast<llvm::PointerType>(tempLV.getAddress().getElementType());
llvm::Value *zero = CGM.getNullPointer(ty, tempLV.getType());
// If __weak, we want to use a barrier under certain conditions.
if (lifetime == Qualifiers::OCL_Weak)
EmitARCInitWeak(tempLV.getAddress(), zero);
// Otherwise just do a simple store.
else
EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
}
// Emit the initializer.
llvm::Value *value = nullptr;
switch (lifetime) {
case Qualifiers::OCL_None:
llvm_unreachable("present but none");
case Qualifiers::OCL_Strong: {
if (!D || !isa<VarDecl>(D) || !cast<VarDecl>(D)->isARCPseudoStrong()) {
value = EmitARCRetainScalarExpr(init);
break;
}
// If D is pseudo-strong, treat it like __unsafe_unretained here. This means
// that we omit the retain, and causes non-autoreleased return values to be
// immediately released.
[[fallthrough]];
}
case Qualifiers::OCL_ExplicitNone:
value = EmitARCUnsafeUnretainedScalarExpr(init);
break;
case Qualifiers::OCL_Weak: {
// If it's not accessed by the initializer, try to emit the
// initialization with a copy or move.
if (!accessedByInit && tryEmitARCCopyWeakInit(*this, lvalue, init)) {
return;
}
// No way to optimize a producing initializer into this. It's not
// worth optimizing for, because the value will immediately
// disappear in the common case.
value = EmitScalarExpr(init);
if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
if (accessedByInit)
EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
else
EmitARCInitWeak(lvalue.getAddress(), value);
return;
}
case Qualifiers::OCL_Autoreleasing:
value = EmitARCRetainAutoreleaseScalarExpr(init);
break;
}
if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
EmitNullabilityCheck(lvalue, value, init->getExprLoc());
// If the variable might have been accessed by its initializer, we
// might have to initialize with a barrier. We have to do this for
// both __weak and __strong, but __weak got filtered out above.
if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
llvm::Value *oldValue = EmitLoadOfScalar(lvalue, init->getExprLoc());
EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
EmitARCRelease(oldValue, ARCImpreciseLifetime);
return;
}
EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
}
/// Decide whether we can emit the non-zero parts of the specified initializer
/// with equal or fewer than NumStores scalar stores.
static bool canEmitInitWithFewStoresAfterBZero(llvm::Constant *Init,
unsigned &NumStores) {
// Zero and Undef never requires any extra stores.
if (isa<llvm::ConstantAggregateZero>(Init) ||
isa<llvm::ConstantPointerNull>(Init) ||
isa<llvm::UndefValue>(Init))
return true;
if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
isa<llvm::ConstantExpr>(Init))
return Init->isNullValue() || NumStores--;
// See if we can emit each element.
if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
if (!canEmitInitWithFewStoresAfterBZero(Elt, NumStores))
return false;
}
return true;
}
if (llvm::ConstantDataSequential *CDS =
dyn_cast<llvm::ConstantDataSequential>(Init)) {
for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
llvm::Constant *Elt = CDS->getElementAsConstant(i);
if (!canEmitInitWithFewStoresAfterBZero(Elt, NumStores))
return false;
}
return true;
}
// Anything else is hard and scary.
return false;
}
/// For inits that canEmitInitWithFewStoresAfterBZero returned true for, emit
/// the scalar stores that would be required.
void CodeGenFunction::emitStoresForInitAfterBZero(llvm::Constant *Init,
Address Loc, bool isVolatile,
bool IsAutoInit) {
assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
"called emitStoresForInitAfterBZero for zero or undef value.");
if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
isa<llvm::ConstantExpr>(Init)) {
auto *I = Builder.CreateStore(Init, Loc, isVolatile);
addInstToCurrentSourceAtom(I, nullptr);
if (IsAutoInit)
I->addAnnotationMetadata("auto-init");
return;
}
if (llvm::ConstantDataSequential *CDS =
dyn_cast<llvm::ConstantDataSequential>(Init)) {
for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
llvm::Constant *Elt = CDS->getElementAsConstant(i);
// If necessary, get a pointer to the element and emit it.
if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
emitStoresForInitAfterBZero(
Elt, Builder.CreateConstInBoundsGEP2_32(Loc, 0, i), isVolatile,
IsAutoInit);
}
return;
}
assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
"Unknown value type!");
for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
// If necessary, get a pointer to the element and emit it.
if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
emitStoresForInitAfterBZero(Elt,
Builder.CreateConstInBoundsGEP2_32(Loc, 0, i),
isVolatile, IsAutoInit);
}
}
/// Decide whether we should use bzero plus some stores to initialize a local
/// variable instead of using a memcpy from a constant global. It is beneficial
/// to use bzero if the global is all zeros, or mostly zeros and large.
static bool shouldUseBZeroPlusStoresToInitialize(llvm::Constant *Init,
uint64_t GlobalSize) {
// If a global is all zeros, always use a bzero.
if (isa<llvm::ConstantAggregateZero>(Init)) return true;
// If a non-zero global is <= 32 bytes, always use a memcpy. If it is large,
// do it if it will require 6 or fewer scalar stores.
// TODO: Should budget depends on the size? Avoiding a large global warrants
// plopping in more stores.
unsigned StoreBudget = 6;
uint64_t SizeLimit = 32;
return GlobalSize > SizeLimit &&
canEmitInitWithFewStoresAfterBZero(Init, StoreBudget);
}
/// Decide whether we should use memset to initialize a local variable instead
/// of using a memcpy from a constant global. Assumes we've already decided to
/// not user bzero.
/// FIXME We could be more clever, as we are for bzero above, and generate
/// memset followed by stores. It's unclear that's worth the effort.
static llvm::Value *shouldUseMemSetToInitialize(llvm::Constant *Init,
uint64_t GlobalSize,
const llvm::DataLayout &DL) {
uint64_t SizeLimit = 32;
if (GlobalSize <= SizeLimit)
return nullptr;
return llvm::isBytewiseValue(Init, DL);
}
/// Decide whether we want to split a constant structure or array store into a
/// sequence of its fields' stores. This may cost us code size and compilation
/// speed, but plays better with store optimizations.
static bool shouldSplitConstantStore(CodeGenModule &CGM,
uint64_t GlobalByteSize) {
// Don't break things that occupy more than one cacheline.
uint64_t ByteSizeLimit = 64;
if (CGM.getCodeGenOpts().OptimizationLevel == 0)
return false;
if (GlobalByteSize <= ByteSizeLimit)
return true;
return false;
}
enum class IsPattern { No, Yes };
/// Generate a constant filled with either a pattern or zeroes.
static llvm::Constant *patternOrZeroFor(CodeGenModule &CGM, IsPattern isPattern,
llvm::Type *Ty) {
if (isPattern == IsPattern::Yes)
return initializationPatternFor(CGM, Ty);
else
return llvm::Constant::getNullValue(Ty);
}
static llvm::Constant *constWithPadding(CodeGenModule &CGM, IsPattern isPattern,
llvm::Constant *constant);
/// Helper function for constWithPadding() to deal with padding in structures.
static llvm::Constant *constStructWithPadding(CodeGenModule &CGM,
IsPattern isPattern,
llvm::StructType *STy,
llvm::Constant *constant) {
const llvm::DataLayout &DL = CGM.getDataLayout();
const llvm::StructLayout *Layout = DL.getStructLayout(STy);
llvm::Type *Int8Ty = llvm::IntegerType::getInt8Ty(CGM.getLLVMContext());
unsigned SizeSoFar = 0;
SmallVector<llvm::Constant *, 8> Values;
bool NestedIntact = true;
for (unsigned i = 0, e = STy->getNumElements(); i != e; i++) {
unsigned CurOff = Layout->getElementOffset(i);
if (SizeSoFar < CurOff) {
assert(!STy->isPacked());
auto *PadTy = llvm::ArrayType::get(Int8Ty, CurOff - SizeSoFar);
Values.push_back(patternOrZeroFor(CGM, isPattern, PadTy));
}
llvm::Constant *CurOp;
if (constant->isNullValue())
CurOp = llvm::Constant::getNullValue(STy->getElementType(i));
else
CurOp = cast<llvm::Constant>(constant->getAggregateElement(i));
auto *NewOp = constWithPadding(CGM, isPattern, CurOp);
if (CurOp != NewOp)
NestedIntact = false;
Values.push_back(NewOp);
SizeSoFar = CurOff + DL.getTypeAllocSize(CurOp->getType());
}
unsigned TotalSize = Layout->getSizeInBytes();
if (SizeSoFar < TotalSize) {
auto *PadTy = llvm::ArrayType::get(Int8Ty, TotalSize - SizeSoFar);
Values.push_back(patternOrZeroFor(CGM, isPattern, PadTy));
}
if (NestedIntact && Values.size() == STy->getNumElements())
return constant;
return llvm::ConstantStruct::getAnon(Values, STy->isPacked());
}
/// Replace all padding bytes in a given constant with either a pattern byte or
/// 0x00.
static llvm::Constant *constWithPadding(CodeGenModule &CGM, IsPattern isPattern,
llvm::Constant *constant) {
llvm::Type *OrigTy = constant->getType();
if (const auto STy = dyn_cast<llvm::StructType>(OrigTy))
return constStructWithPadding(CGM, isPattern, STy, constant);
if (auto *ArrayTy = dyn_cast<llvm::ArrayType>(OrigTy)) {
llvm::SmallVector<llvm::Constant *, 8> Values;
uint64_t Size = ArrayTy->getNumElements();
if (!Size)
return constant;
llvm::Type *ElemTy = ArrayTy->getElementType();
bool ZeroInitializer = constant->isNullValue();
llvm::Constant *OpValue, *PaddedOp;
if (ZeroInitializer) {
OpValue = llvm::Constant::getNullValue(ElemTy);
PaddedOp = constWithPadding(CGM, isPattern, OpValue);
}
for (unsigned Op = 0; Op != Size; ++Op) {
if (!ZeroInitializer) {
OpValue = constant->getAggregateElement(Op);
PaddedOp = constWithPadding(CGM, isPattern, OpValue);
}
Values.push_back(PaddedOp);
}
auto *NewElemTy = Values[0]->getType();
if (NewElemTy == ElemTy)
return constant;
auto *NewArrayTy = llvm::ArrayType::get(NewElemTy, Size);
return llvm::ConstantArray::get(NewArrayTy, Values);
}
// FIXME: Add handling for tail padding in vectors. Vectors don't
// have padding between or inside elements, but the total amount of
// data can be less than the allocated size.
return constant;
}
Address CodeGenModule::createUnnamedGlobalFrom(const VarDecl &D,
llvm::Constant *Constant,
CharUnits Align) {
auto FunctionName = [&](const DeclContext *DC) -> std::string {
if (const auto *FD = dyn_cast<FunctionDecl>(DC)) {
if (const auto *CC = dyn_cast<CXXConstructorDecl>(FD))
return CC->getNameAsString();
if (const auto *CD = dyn_cast<CXXDestructorDecl>(FD))
return CD->getNameAsString();
return std::string(getMangledName(FD));
} else if (const auto *OM = dyn_cast<ObjCMethodDecl>(DC)) {
return OM->getNameAsString();
} else if (isa<BlockDecl>(DC)) {
return "<block>";
} else if (isa<CapturedDecl>(DC)) {
return "<captured>";
} else {
llvm_unreachable("expected a function or method");
}
};
// Form a simple per-variable cache of these values in case we find we
// want to reuse them.
llvm::GlobalVariable *&CacheEntry = InitializerConstants[&D];
if (!CacheEntry || CacheEntry->getInitializer() != Constant) {
auto *Ty = Constant->getType();
bool isConstant = true;
llvm::GlobalVariable *InsertBefore = nullptr;
unsigned AS =
getContext().getTargetAddressSpace(GetGlobalConstantAddressSpace());
std::string Name;
if (D.hasGlobalStorage())
Name = getMangledName(&D).str() + ".const";
else if (const DeclContext *DC = D.getParentFunctionOrMethod())
Name = ("__const." + FunctionName(DC) + "." + D.getName()).str();
else
llvm_unreachable("local variable has no parent function or method");
llvm::GlobalVariable *GV = new llvm::GlobalVariable(
getModule(), Ty, isConstant, llvm::GlobalValue::PrivateLinkage,
Constant, Name, InsertBefore, llvm::GlobalValue::NotThreadLocal, AS);
GV->setAlignment(Align.getAsAlign());
GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
CacheEntry = GV;
} else if (CacheEntry->getAlign().valueOrOne() < Align.getAsAlign()) {
CacheEntry->setAlignment(Align.getAsAlign());
}
return Address(CacheEntry, CacheEntry->getValueType(), Align);
}
static Address createUnnamedGlobalForMemcpyFrom(CodeGenModule &CGM,
const VarDecl &D,
CGBuilderTy &Builder,
llvm::Constant *Constant,
CharUnits Align) {
Address SrcPtr = CGM.createUnnamedGlobalFrom(D, Constant, Align);
return SrcPtr.withElementType(CGM.Int8Ty);
}
void CodeGenFunction::emitStoresForConstant(const VarDecl &D, Address Loc,
bool isVolatile,
llvm::Constant *constant,
bool IsAutoInit) {
auto *Ty = constant->getType();
uint64_t ConstantSize = CGM.getDataLayout().getTypeAllocSize(Ty);
if (!ConstantSize)
return;
bool canDoSingleStore = Ty->isIntOrIntVectorTy() ||
Ty->isPtrOrPtrVectorTy() || Ty->isFPOrFPVectorTy();
if (canDoSingleStore) {
auto *I = Builder.CreateStore(constant, Loc, isVolatile);
addInstToCurrentSourceAtom(I, nullptr);
if (IsAutoInit)
I->addAnnotationMetadata("auto-init");
return;
}
auto *SizeVal = llvm::ConstantInt::get(CGM.IntPtrTy, ConstantSize);
// If the initializer is all or mostly the same, codegen with bzero / memset
// then do a few stores afterward.
if (shouldUseBZeroPlusStoresToInitialize(constant, ConstantSize)) {
auto *I = Builder.CreateMemSet(Loc, llvm::ConstantInt::get(CGM.Int8Ty, 0),
SizeVal, isVolatile);
addInstToCurrentSourceAtom(I, nullptr);
if (IsAutoInit)
I->addAnnotationMetadata("auto-init");
bool valueAlreadyCorrect =
constant->isNullValue() || isa<llvm::UndefValue>(constant);
if (!valueAlreadyCorrect) {
Loc = Loc.withElementType(Ty);
emitStoresForInitAfterBZero(constant, Loc, isVolatile, IsAutoInit);
}
return;
}
// If the initializer is a repeated byte pattern, use memset.
llvm::Value *Pattern =
shouldUseMemSetToInitialize(constant, ConstantSize, CGM.getDataLayout());
if (Pattern) {
uint64_t Value = 0x00;
if (!isa<llvm::UndefValue>(Pattern)) {
const llvm::APInt &AP = cast<llvm::ConstantInt>(Pattern)->getValue();
assert(AP.getBitWidth() <= 8);
Value = AP.getLimitedValue();
}
auto *I = Builder.CreateMemSet(
Loc, llvm::ConstantInt::get(CGM.Int8Ty, Value), SizeVal, isVolatile);
addInstToCurrentSourceAtom(I, nullptr);
if (IsAutoInit)
I->addAnnotationMetadata("auto-init");
return;
}
// If the initializer is small or trivialAutoVarInit is set, use a handful of
// stores.
bool IsTrivialAutoVarInitPattern =
CGM.getContext().getLangOpts().getTrivialAutoVarInit() ==
LangOptions::TrivialAutoVarInitKind::Pattern;
if (shouldSplitConstantStore(CGM, ConstantSize)) {
if (auto *STy = dyn_cast<llvm::StructType>(Ty)) {
if (STy == Loc.getElementType() || IsTrivialAutoVarInitPattern) {
const llvm::StructLayout *Layout =
CGM.getDataLayout().getStructLayout(STy);
for (unsigned i = 0; i != constant->getNumOperands(); i++) {
CharUnits CurOff =
CharUnits::fromQuantity(Layout->getElementOffset(i));
Address EltPtr = Builder.CreateConstInBoundsByteGEP(
Loc.withElementType(CGM.Int8Ty), CurOff);
emitStoresForConstant(D, EltPtr, isVolatile,
constant->getAggregateElement(i), IsAutoInit);
}
return;
}
} else if (auto *ATy = dyn_cast<llvm::ArrayType>(Ty)) {
if (ATy == Loc.getElementType() || IsTrivialAutoVarInitPattern) {
for (unsigned i = 0; i != ATy->getNumElements(); i++) {
Address EltPtr = Builder.CreateConstGEP(
Loc.withElementType(ATy->getElementType()), i);
emitStoresForConstant(D, EltPtr, isVolatile,
constant->getAggregateElement(i), IsAutoInit);
}
return;
}
}
}
// Copy from a global.
auto *I =
Builder.CreateMemCpy(Loc,
createUnnamedGlobalForMemcpyFrom(
CGM, D, Builder, constant, Loc.getAlignment()),
SizeVal, isVolatile);
addInstToCurrentSourceAtom(I, nullptr);
if (IsAutoInit)
I->addAnnotationMetadata("auto-init");
}
void CodeGenFunction::emitStoresForZeroInit(const VarDecl &D, Address Loc,
bool isVolatile) {
llvm::Type *ElTy = Loc.getElementType();
llvm::Constant *constant =
constWithPadding(CGM, IsPattern::No, llvm::Constant::getNullValue(ElTy));
emitStoresForConstant(D, Loc, isVolatile, constant,
/*IsAutoInit=*/true);
}
void CodeGenFunction::emitStoresForPatternInit(const VarDecl &D, Address Loc,
bool isVolatile) {
llvm::Type *ElTy = Loc.getElementType();
llvm::Constant *constant = constWithPadding(
CGM, IsPattern::Yes, initializationPatternFor(CGM, ElTy));
assert(!isa<llvm::UndefValue>(constant));
emitStoresForConstant(D, Loc, isVolatile, constant,
/*IsAutoInit=*/true);
}
static bool containsUndef(llvm::Constant *constant) {
auto *Ty = constant->getType();
if (isa<llvm::UndefValue>(constant))
return true;
if (Ty->isStructTy() || Ty->isArrayTy() || Ty->isVectorTy())
for (llvm::Use &Op : constant->operands())
if (containsUndef(cast<llvm::Constant>(Op)))
return true;
return false;
}
static llvm::Constant *replaceUndef(CodeGenModule &CGM, IsPattern isPattern,
llvm::Constant *constant) {
auto *Ty = constant->getType();
if (isa<llvm::UndefValue>(constant))
return patternOrZeroFor(CGM, isPattern, Ty);
if (!(Ty->isStructTy() || Ty->isArrayTy() || Ty->isVectorTy()))
return constant;
if (!containsUndef(constant))
return constant;
llvm::SmallVector<llvm::Constant *, 8> Values(constant->getNumOperands());
for (unsigned Op = 0, NumOp = constant->getNumOperands(); Op != NumOp; ++Op) {
auto *OpValue = cast<llvm::Constant>(constant->getOperand(Op));
Values[Op] = replaceUndef(CGM, isPattern, OpValue);
}
if (Ty->isStructTy())
return llvm::ConstantStruct::get(cast<llvm::StructType>(Ty), Values);
if (Ty->isArrayTy())
return llvm::ConstantArray::get(cast<llvm::ArrayType>(Ty), Values);
assert(Ty->isVectorTy());
return llvm::ConstantVector::get(Values);
}
/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
/// variable declaration with auto, register, or no storage class specifier.
/// These turn into simple stack objects, or GlobalValues depending on target.
void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
AutoVarEmission emission = EmitAutoVarAlloca(D);
EmitAutoVarInit(emission);
EmitAutoVarCleanups(emission);
}
/// Emit a lifetime.begin marker if some criteria are satisfied.
/// \return whether the marker was emitted.
bool CodeGenFunction::EmitLifetimeStart(llvm::Value *Addr) {
if (!ShouldEmitLifetimeMarkers)
return false;
assert(Addr->getType()->getPointerAddressSpace() ==
CGM.getDataLayout().getAllocaAddrSpace() &&
"Pointer should be in alloca address space");
Builder.CreateCall(CGM.getLLVMLifetimeStartFn(), {Addr});
return true;
}
void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Addr) {
if (!ShouldEmitLifetimeMarkers)
return;
assert(Addr->getType()->getPointerAddressSpace() ==
CGM.getDataLayout().getAllocaAddrSpace() &&
"Pointer should be in alloca address space");
Builder.CreateCall(CGM.getLLVMLifetimeEndFn(), {Addr});
}
void CodeGenFunction::EmitFakeUse(Address Addr) {
auto NL = ApplyDebugLocation::CreateEmpty(*this);
llvm::Value *V = Builder.CreateLoad(Addr, "fake.use");
llvm::CallInst *C = Builder.CreateCall(CGM.getLLVMFakeUseFn(), {V});
C->setTailCallKind(llvm::CallInst::TCK_NoTail);
}
void CodeGenFunction::EmitAndRegisterVariableArrayDimensions(
CGDebugInfo *DI, const VarDecl &D, bool EmitDebugInfo) {
// For each dimension stores its QualType and corresponding
// size-expression Value.
SmallVector<CodeGenFunction::VlaSizePair, 4> Dimensions;
SmallVector<const IdentifierInfo *, 4> VLAExprNames;
// Break down the array into individual dimensions.
QualType Type1D = D.getType();
while (getContext().getAsVariableArrayType(Type1D)) {
auto VlaSize = getVLAElements1D(Type1D);
if (auto *C = dyn_cast<llvm::ConstantInt>(VlaSize.NumElts))
Dimensions.emplace_back(C, Type1D.getUnqualifiedType());
else {
// Generate a locally unique name for the size expression.
Twine Name = Twine("__vla_expr") + Twine(VLAExprCounter++);
SmallString<12> Buffer;
StringRef NameRef = Name.toStringRef(Buffer);
auto &Ident = getContext().Idents.getOwn(NameRef);
VLAExprNames.push_back(&Ident);
auto SizeExprAddr =
CreateDefaultAlignTempAlloca(VlaSize.NumElts->getType(), NameRef);
Builder.CreateStore(VlaSize.NumElts, SizeExprAddr);
Dimensions.emplace_back(SizeExprAddr.getPointer(),
Type1D.getUnqualifiedType());
}
Type1D = VlaSize.Type;
}
if (!EmitDebugInfo)
return;
// Register each dimension's size-expression with a DILocalVariable,
// so that it can be used by CGDebugInfo when instantiating a DISubrange
// to describe this array.
unsigned NameIdx = 0;
for (auto &VlaSize : Dimensions) {
llvm::Metadata *MD;
if (auto *C = dyn_cast<llvm::ConstantInt>(VlaSize.NumElts))
MD = llvm::ConstantAsMetadata::get(C);
else {
// Create an artificial VarDecl to generate debug info for.
const IdentifierInfo *NameIdent = VLAExprNames[NameIdx++];
auto QT = getContext().getIntTypeForBitwidth(
SizeTy->getScalarSizeInBits(), false);
auto *ArtificialDecl = VarDecl::Create(
getContext(), const_cast<DeclContext *>(D.getDeclContext()),
D.getLocation(), D.getLocation(), NameIdent, QT,
getContext().CreateTypeSourceInfo(QT), SC_Auto);
ArtificialDecl->setImplicit();
MD = DI->EmitDeclareOfAutoVariable(ArtificialDecl, VlaSize.NumElts,
Builder);
}
assert(MD && "No Size expression debug node created");
DI->registerVLASizeExpression(VlaSize.Type, MD);
}
}
/// Return the maximum size of an aggregate for which we generate a fake use
/// intrinsic when -fextend-variable-liveness is in effect.
static uint64_t maxFakeUseAggregateSize(const ASTContext &C) {
return 4 * C.getTypeSize(C.UnsignedIntTy);
}
// Helper function to determine whether a variable's or parameter's lifetime
// should be extended.
static bool shouldExtendLifetime(const ASTContext &Context,
const Decl *FuncDecl, const VarDecl &D,
ImplicitParamDecl *CXXABIThisDecl) {
// When we're not inside a valid function it is unlikely that any
// lifetime extension is useful.
if (!FuncDecl)
return false;
if (FuncDecl->isImplicit())
return false;
// Do not extend compiler-created variables except for the this pointer.
if (D.isImplicit() && &D != CXXABIThisDecl)
return false;
QualType Ty = D.getType();
// No need to extend volatiles, they have a memory location.
if (Ty.isVolatileQualified())
return false;
// Don't extend variables that exceed a certain size.
if (Context.getTypeSize(Ty) > maxFakeUseAggregateSize(Context))
return false;
// Do not extend variables in nodebug or optnone functions.
if (FuncDecl->hasAttr<NoDebugAttr>() || FuncDecl->hasAttr<OptimizeNoneAttr>())
return false;
return true;
}
/// EmitAutoVarAlloca - Emit the alloca and debug information for a
/// local variable. Does not emit initialization or destruction.
CodeGenFunction::AutoVarEmission
CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
QualType Ty = D.getType();
assert(
Ty.getAddressSpace() == LangAS::Default ||
(Ty.getAddressSpace() == LangAS::opencl_private && getLangOpts().OpenCL));
AutoVarEmission emission(D);
bool isEscapingByRef = D.isEscapingByref();
emission.IsEscapingByRef = isEscapingByRef;
CharUnits alignment = getContext().getDeclAlign(&D);
// If the type is variably-modified, emit all the VLA sizes for it.
if (Ty->isVariablyModifiedType())
EmitVariablyModifiedType(Ty);
auto *DI = getDebugInfo();
bool EmitDebugInfo = DI && CGM.getCodeGenOpts().hasReducedDebugInfo();
Address address = Address::invalid();
RawAddress AllocaAddr = RawAddress::invalid();
Address OpenMPLocalAddr = Address::invalid();
if (CGM.getLangOpts().OpenMPIRBuilder)
OpenMPLocalAddr = OMPBuilderCBHelpers::getAddressOfLocalVariable(*this, &D);
else
OpenMPLocalAddr =
getLangOpts().OpenMP
? CGM.getOpenMPRuntime().getAddressOfLocalVariable(*this, &D)
: Address::invalid();
bool NRVO = getLangOpts().ElideConstructors && D.isNRVOVariable();
if (getLangOpts().OpenMP && OpenMPLocalAddr.isValid()) {
address = OpenMPLocalAddr;
AllocaAddr = OpenMPLocalAddr;
} else if (Ty->isConstantSizeType()) {
// If this value is an array or struct with a statically determinable
// constant initializer, there are optimizations we can do.
//
// TODO: We should be able to delete most of the restrictions here; there's
// no reason we specifically need a POD array/record type. But we'd need to
// evaluate the performance, update regression tests, and fix a crash with
// OpenMP.
if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
(D.isConstexpr() ||
((Ty.isPODType(getContext()) ||
getContext().getBaseElementType(Ty)->isObjCObjectPointerType())))) {
emission.ConstantAggregateInitializer =
ConstantEmitter(*this).tryEmitAbstractForInitializer(D);
if (emission.ConstantAggregateInitializer) {
// If the variable's a const type, and it's neither an NRVO
// candidate nor a __block variable and has no mutable members,
// emit it as a global instead.
// Exception is if a variable is located in non-constant address space
// in OpenCL.
bool NeedsDtor =
D.needsDestruction(getContext()) == QualType::DK_cxx_destructor;
if ((!getLangOpts().OpenCL ||
Ty.getAddressSpace() == LangAS::opencl_constant) &&
(CGM.getCodeGenOpts().MergeAllConstants && !NRVO &&
!isEscapingByRef &&
Ty.isConstantStorage(getContext(), true, !NeedsDtor))) {
EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
// Signal this condition to later callbacks.
emission.Addr = Address::invalid();
assert(emission.wasEmittedAsGlobal());
return emission;
}
}
}
// A normal fixed sized variable becomes an alloca in the entry block,
// unless:
// - it's an NRVO variable.
// - we are compiling OpenMP and it's an OpenMP local variable.
if (NRVO) {
// The named return value optimization: allocate this variable in the
// return slot, so that we can elide the copy when returning this
// variable (C++0x [class.copy]p34).
AllocaAddr =
RawAddress(ReturnValue.emitRawPointer(*this),
ReturnValue.getElementType(), ReturnValue.getAlignment());
address = MaybeCastStackAddressSpace(AllocaAddr, Ty.getAddressSpace());
if (const auto *RD = Ty->getAsRecordDecl()) {
if (const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
(CXXRD && !CXXRD->hasTrivialDestructor()) ||
RD->isNonTrivialToPrimitiveDestroy()) {
// Create a flag that is used to indicate when the NRVO was applied
// to this variable. Set it to zero to indicate that NRVO was not
// applied.
llvm::Value *Zero = Builder.getFalse();
RawAddress NRVOFlag =
CreateTempAlloca(Zero->getType(), CharUnits::One(), "nrvo");
EnsureInsertPoint();
Builder.CreateStore(Zero, NRVOFlag);
// Record the NRVO flag for this variable.
NRVOFlags[&D] = NRVOFlag.getPointer();
emission.NRVOFlag = NRVOFlag.getPointer();
}
}
} else {
CharUnits allocaAlignment;
llvm::Type *allocaTy;
if (isEscapingByRef) {
auto &byrefInfo = getBlockByrefInfo(&D);
allocaTy = byrefInfo.Type;
allocaAlignment = byrefInfo.ByrefAlignment;
} else {
allocaTy = ConvertTypeForMem(Ty);
allocaAlignment = alignment;
}
// Create the alloca. Note that we set the name separately from
// building the instruction so that it's there even in no-asserts
// builds.
address = CreateTempAlloca(allocaTy, Ty.getAddressSpace(),
allocaAlignment, D.getName(),
/*ArraySize=*/nullptr, &AllocaAddr);
// Don't emit lifetime markers for MSVC catch parameters. The lifetime of
// the catch parameter starts in the catchpad instruction, and we can't
// insert code in those basic blocks.
bool IsMSCatchParam =
D.isExceptionVariable() && getTarget().getCXXABI().isMicrosoft();
// Emit a lifetime intrinsic if meaningful. There's no point in doing this
// if we don't have a valid insertion point (?).
if (HaveInsertPoint() && !IsMSCatchParam) {
// If there's a jump into the lifetime of this variable, its lifetime
// gets broken up into several regions in IR, which requires more work
// to handle correctly. For now, just omit the intrinsics; this is a
// rare case, and it's better to just be conservatively correct.
// PR28267.
//
// We have to do this in all language modes if there's a jump past the
// declaration. We also have to do it in C if there's a jump to an
// earlier point in the current block because non-VLA lifetimes begin as
// soon as the containing block is entered, not when its variables
// actually come into scope; suppressing the lifetime annotations
// completely in this case is unnecessarily pessimistic, but again, this
// is rare.
if (!Bypasses.IsBypassed(&D) &&
!(!getLangOpts().CPlusPlus && hasLabelBeenSeenInCurrentScope())) {
emission.UseLifetimeMarkers =
EmitLifetimeStart(AllocaAddr.getPointer());
}
} else {
assert(!emission.useLifetimeMarkers());
}
}
// A variable whose declaration is bypassed by a goto or switch is not
// initialized by EmitAutoVarInit, which runs at the declaration. Emit the
// trivial-auto-var-init separately.
if (Bypasses.IsBypassed(&D) && !emission.IsEscapingByRef &&
!Ty->isVariablyModifiedType() &&
getAutoVarInitKind(Ty, D) !=
LangOptions::TrivialAutoVarInitKind::Uninitialized) {
if (!Bypasses.isAlwaysBypassed()) {
// The variable's lifetime restarts on each re-entry into its scope, so
// reinitialize at every bypassing jump. Backward gotos are emitted at
// the jump source, which comes after this alloca; forward gotos and the
// switch dispatch have already been emitted, so patch their init in
// before the jump.
BypassedVarInits.insert({&D, address});
for (const BypassingForwardJump &FG : BypassingForwardJumps) {
const auto *Vars = Bypasses.getBypassedVarsForSource(FG.Source);
if (!Vars || !Vars->contains(&D))
continue;
llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
Builder.SetInsertPoint(FG.Block->getTerminator());
emitZeroOrPatternForAutoVarInit(Ty, D, address);
}
} else {
// A computed goto can jump anywhere, so we can't identify the jumps
// that bypass this declaration. Fall back to initializing once, in the
// function's entry block.
llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
Builder.SetInsertPoint(getPostAllocaInsertPoint());
emitZeroOrPatternForAutoVarInit(Ty, D, address);
}
}
if (D.hasAttr<StackProtectorIgnoreAttr>()) {
if (auto *AI = dyn_cast<llvm::AllocaInst>(address.getBasePointer())) {
llvm::LLVMContext &Ctx = Builder.getContext();
auto *Operand = llvm::ConstantAsMetadata::get(Builder.getInt32(0));
AI->setMetadata("stack-protector", llvm::MDNode::get(Ctx, {Operand}));
}
std::optional<llvm::Attribute::AttrKind> Attr =
CGM.StackProtectorAttribute(&D);
if (Attr && (*Attr == llvm::Attribute::StackProtectReq)) {
CGM.getDiags().Report(D.getLocation(),
diag::warn_stack_protection_ignore_attribute);
}
}
} else {
EnsureInsertPoint();
// Delayed globalization for variable length declarations. This ensures that
// the expression representing the length has been emitted and can be used
// by the definition of the VLA. Since this is an escaped declaration, in
// OpenMP we have to use a call to __kmpc_alloc_shared(). The matching
// deallocation call to __kmpc_free_shared() is emitted later.
bool VarAllocated = false;
if (getLangOpts().OpenMPIsTargetDevice) {
auto &RT = CGM.getOpenMPRuntime();
if (RT.isDelayedVariableLengthDecl(*this, &D)) {
// Emit call to __kmpc_alloc_shared() instead of the alloca.
std::pair<llvm::Value *, llvm::Value *> AddrSizePair =
RT.getKmpcAllocShared(*this, &D);
// Save the address of the allocation:
LValue Base = MakeAddrLValue(AddrSizePair.first, D.getType(),
CGM.getContext().getDeclAlign(&D),
AlignmentSource::Decl);
address = Base.getAddress();
// Push a cleanup block to emit the call to __kmpc_free_shared in the
// appropriate location at the end of the scope of the
// __kmpc_alloc_shared functions:
pushKmpcAllocFree(NormalCleanup, AddrSizePair);
// Mark variable as allocated:
VarAllocated = true;
}
}
if (!VarAllocated) {
if (!DidCallStackSave) {
// Save the stack.
Address Stack =
CreateDefaultAlignTempAlloca(AllocaInt8PtrTy, "saved_stack");
llvm::Value *V = Builder.CreateStackSave();
assert(V->getType() == AllocaInt8PtrTy);
Builder.CreateStore(V, Stack);
DidCallStackSave = true;
// Push a cleanup block and restore the stack there.
// FIXME: in general circumstances, this should be an EH cleanup.
pushStackRestore(NormalCleanup, Stack);
}
auto VlaSize = getVLASize(Ty);
llvm::Type *llvmTy = ConvertTypeForMem(VlaSize.Type);
// Allocate memory for the array.
address = CreateTempAlloca(llvmTy, alignment, "vla", VlaSize.NumElts,
&AllocaAddr);
}
// If we have debug info enabled, properly describe the VLA dimensions for
// this type by registering the vla size expression for each of the
// dimensions.
EmitAndRegisterVariableArrayDimensions(DI, D, EmitDebugInfo);
}
setAddrOfLocalVar(&D, address);
emission.Addr = address;
emission.AllocaAddr = AllocaAddr;
// Emit debug info for local var declaration.
if (EmitDebugInfo && HaveInsertPoint()) {
Address DebugAddr = address;
bool UsePointerValue = NRVO && ReturnValuePointer.isValid();
DI->setLocation(D.getLocation());
// If NRVO, use a pointer to the return address.
if (UsePointerValue) {
DebugAddr = ReturnValuePointer;
AllocaAddr = ReturnValuePointer;
}
(void)DI->EmitDeclareOfAutoVariable(&D, AllocaAddr.getPointer(), Builder,
UsePointerValue);
}
if (D.hasAttr<AnnotateAttr>() && HaveInsertPoint())
EmitVarAnnotations(&D, address.emitRawPointer(*this));
// Make sure we call @llvm.lifetime.end.
if (emission.useLifetimeMarkers())
EHStack.pushCleanup<CallLifetimeEnd>(
NormalEHLifetimeMarker, emission.getOriginalAllocatedAddress());
// Analogous to lifetime markers, we use a 'cleanup' to emit fake.use
// calls for local variables. We are exempting volatile variables and
// non-scalars larger than 4 times the size of an unsigned int. Larger
// non-scalars are often allocated in memory and may create unnecessary
// overhead.
if (CGM.getCodeGenOpts().getExtendVariableLiveness() ==
CodeGenOptions::ExtendVariableLivenessKind::All) {
if (shouldExtendLifetime(getContext(), CurCodeDecl, D, CXXABIThisDecl))
EHStack.pushCleanup<FakeUse>(NormalFakeUse,
emission.getAllocatedAddress());
}
return emission;
}
static bool isCapturedBy(const VarDecl &, const Expr *);
/// Determines whether the given __block variable is potentially
/// captured by the given statement.
static bool isCapturedBy(const VarDecl &Var, const Stmt *S) {
if (const Expr *E = dyn_cast<Expr>(S))
return isCapturedBy(Var, E);
for (const Stmt *SubStmt : S->children())
if (isCapturedBy(Var, SubStmt))
return true;
return false;
}
/// Determines whether the given __block variable is potentially
/// captured by the given expression.
static bool isCapturedBy(const VarDecl &Var, const Expr *E) {
// Skip the most common kinds of expressions that make
// hierarchy-walking expensive.
E = E->IgnoreParenCasts();
if (const BlockExpr *BE = dyn_cast<BlockExpr>(E)) {
const BlockDecl *Block = BE->getBlockDecl();
for (const auto &I : Block->captures()) {
if (I.getVariable() == &Var)
return true;
}
// No need to walk into the subexpressions.
return false;
}
if (const StmtExpr *SE = dyn_cast<StmtExpr>(E)) {
const CompoundStmt *CS = SE->getSubStmt();
for (const auto *BI : CS->body())
if (const auto *BIE = dyn_cast<Expr>(BI)) {
if (isCapturedBy(Var, BIE))
return true;
}
else if (const auto *DS = dyn_cast<DeclStmt>(BI)) {
// special case declarations
for (const auto *I : DS->decls()) {
if (const auto *VD = dyn_cast<VarDecl>((I))) {
const Expr *Init = VD->getInit();
if (Init && isCapturedBy(Var, Init))
return true;
}
}
}
else
// FIXME. Make safe assumption assuming arbitrary statements cause capturing.
// Later, provide code to poke into statements for capture analysis.
return true;
return false;
}
for (const Stmt *SubStmt : E->children())
if (isCapturedBy(Var, SubStmt))
return true;
return false;
}
/// Determine whether the given initializer is trivial in the sense
/// that it requires no code to be generated.
bool CodeGenFunction::isTrivialInitializer(const Expr *Init) {
if (!Init)
return true;
if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
if (CXXConstructorDecl *Constructor = Construct->getConstructor())
if (Constructor->isTrivial() &&
Constructor->isDefaultConstructor() &&
!Construct->requiresZeroInitialization())
return true;
return false;
}
LangOptions::TrivialAutoVarInitKind
CodeGenFunction::getAutoVarInitKind(QualType Ty, const VarDecl &D) {
auto hasNoTrivialAutoVarInitAttr = [](const Decl *D) {
return D && D->hasAttr<NoTrivialAutoVarInitAttr>();
};
if (D.isConstexpr() || D.getAttr<UninitializedAttr>() ||
hasNoTrivialAutoVarInitAttr(Ty->getAsTagDecl()) ||
hasNoTrivialAutoVarInitAttr(CurFuncDecl))
return LangOptions::TrivialAutoVarInitKind::Uninitialized;
return getContext().getLangOpts().getTrivialAutoVarInit();
}
void CodeGenFunction::emitBypassedVarInitsForSource(const Stmt *Source) {
// Scope-reentry reinit is only sound when jump sources are known. With a
// computed goto we can't tell whether a jump leaves a variable's scope, so
// EmitAutoVarAlloca falls back to a single function-scope init and we must
// not reinitialize here -- doing so could clobber a still-live variable.
if (Bypasses.isAlwaysBypassed())
return;
const auto *Vars = Bypasses.getBypassedVarsForSource(Source);
if (!Vars)
return;
for (const VarDecl *VD : *Vars) {
auto It = BypassedVarInits.find(VD);
if (It != BypassedVarInits.end())
emitZeroOrPatternForAutoVarInit(VD->getType(), *VD, It->second);
}
}
void CodeGenFunction::emitZeroOrPatternForAutoVarInit(QualType type,
const VarDecl &D,
Address Loc) {
auto trivialAutoVarInit = getContext().getLangOpts().getTrivialAutoVarInit();
auto trivialAutoVarInitMaxSize =
getContext().getLangOpts().TrivialAutoVarInitMaxSize;
CharUnits Size = getContext().getTypeSizeInChars(type);
bool isVolatile = type.isVolatileQualified();
if (!Size.isZero()) {
// We skip auto-init variables by their alloc size. Take this as an example:
// "struct Foo {int x; char buff[1024];}" Assume the max-size flag is 1023.
// All Foo type variables will be skipped. Ideally, we only skip the buff
// array and still auto-init X in this example.
// TODO: Improve the size filtering to by member size.
auto allocSize = CGM.getDataLayout().getTypeAllocSize(Loc.getElementType());
switch (trivialAutoVarInit) {
case LangOptions::TrivialAutoVarInitKind::Uninitialized:
llvm_unreachable("Uninitialized handled by caller");
case LangOptions::TrivialAutoVarInitKind::Zero:
if (CGM.stopAutoInit())
return;
if (trivialAutoVarInitMaxSize > 0 &&
allocSize > trivialAutoVarInitMaxSize)
return;
emitStoresForZeroInit(D, Loc, isVolatile);
break;
case LangOptions::TrivialAutoVarInitKind::Pattern:
if (CGM.stopAutoInit())
return;
if (trivialAutoVarInitMaxSize > 0 &&
allocSize > trivialAutoVarInitMaxSize)
return;
emitStoresForPatternInit(D, Loc, isVolatile);
break;
}
return;
}
// VLAs look zero-sized to getTypeInfo. We can't emit constant stores to
// them, so emit a memcpy with the VLA size to initialize each element.
// Technically zero-sized or negative-sized VLAs are undefined, and UBSan
// will catch that code, but there exists code which generates zero-sized
// VLAs. Be nice and initialize whatever they requested.
const auto *VlaType = getContext().getAsVariableArrayType(type);
if (!VlaType)
return;
auto VlaSize = getVLASize(VlaType);
auto SizeVal = VlaSize.NumElts;
CharUnits EltSize = getContext().getTypeSizeInChars(VlaSize.Type);
switch (trivialAutoVarInit) {
case LangOptions::TrivialAutoVarInitKind::Uninitialized:
llvm_unreachable("Uninitialized handled by caller");
case LangOptions::TrivialAutoVarInitKind::Zero: {
if (CGM.stopAutoInit())
return;
if (!EltSize.isOne())
SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(EltSize));
auto *I = Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0),
SizeVal, isVolatile);
I->addAnnotationMetadata("auto-init");
break;
}
case LangOptions::TrivialAutoVarInitKind::Pattern: {
if (CGM.stopAutoInit())
return;
llvm::Type *ElTy = Loc.getElementType();
llvm::Constant *Constant = constWithPadding(
CGM, IsPattern::Yes, initializationPatternFor(CGM, ElTy));
CharUnits ConstantAlign = getContext().getTypeAlignInChars(VlaSize.Type);
llvm::BasicBlock *SetupBB = createBasicBlock("vla-setup.loop");
llvm::BasicBlock *LoopBB = createBasicBlock("vla-init.loop");
llvm::BasicBlock *ContBB = createBasicBlock("vla-init.cont");
llvm::Value *IsZeroSizedVLA = Builder.CreateICmpEQ(
SizeVal, llvm::ConstantInt::get(SizeVal->getType(), 0),
"vla.iszerosized");
Builder.CreateCondBr(IsZeroSizedVLA, ContBB, SetupBB);
EmitBlock(SetupBB);
if (!EltSize.isOne())
SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(EltSize));
llvm::Value *BaseSizeInChars =
llvm::ConstantInt::get(IntPtrTy, EltSize.getQuantity());
Address Begin = Loc.withElementType(Int8Ty);
llvm::Value *End = Builder.CreateInBoundsGEP(Begin.getElementType(),
Begin.emitRawPointer(*this),
SizeVal, "vla.end");
llvm::BasicBlock *OriginBB = Builder.GetInsertBlock();
EmitBlock(LoopBB);
llvm::PHINode *Cur = Builder.CreatePHI(Begin.getType(), 2, "vla.cur");
Cur->addIncoming(Begin.emitRawPointer(*this), OriginBB);
CharUnits CurAlign = Loc.getAlignment().alignmentOfArrayElement(EltSize);
auto *I =
Builder.CreateMemCpy(Address(Cur, Int8Ty, CurAlign),
createUnnamedGlobalForMemcpyFrom(
CGM, D, Builder, Constant, ConstantAlign),
BaseSizeInChars, isVolatile);
I->addAnnotationMetadata("auto-init");
llvm::Value *Next =
Builder.CreateInBoundsGEP(Int8Ty, Cur, BaseSizeInChars, "vla.next");
llvm::Value *Done = Builder.CreateICmpEQ(Next, End, "vla-init.isdone");
Builder.CreateCondBr(Done, ContBB, LoopBB);
Cur->addIncoming(Next, LoopBB);
EmitBlock(ContBB);
} break;
}
}
void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
assert(emission.Variable && "emission was not valid!");
// If this was emitted as a global constant, we're done.
if (emission.wasEmittedAsGlobal()) return;
const VarDecl &D = *emission.Variable;
auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, D.getLocation());
ApplyAtomGroup Grp(getDebugInfo());
QualType type = D.getType();
// If this local has an initializer, emit it now.
const Expr *Init = D.getInit();
// If we are at an unreachable point, we don't need to emit the initializer
// unless it contains a label.
if (!HaveInsertPoint()) {
if (!Init || !ContainsLabel(Init)) {
PGO->markStmtMaybeUsed(Init);
return;
}
EnsureInsertPoint();
}
// Initialize the structure of a __block variable.
if (emission.IsEscapingByRef)
emitByrefStructureInit(emission);
// Initialize the variable here if it doesn't have a initializer and it is a
// C struct that is non-trivial to initialize or an array containing such a
// struct.
if (!Init &&
type.isNonTrivialToPrimitiveDefaultInitialize() ==
QualType::PDIK_Struct) {
LValue Dst = MakeAddrLValue(emission.getAllocatedAddress(), type);
if (emission.IsEscapingByRef)
drillIntoBlockVariable(*this, Dst, &D);
defaultInitNonTrivialCStructVar(Dst);
return;
}
// Check whether this is a byref variable that's potentially
// captured and moved by its own initializer. If so, we'll need to
// emit the initializer first, then copy into the variable.
bool capturedByInit =
Init && emission.IsEscapingByRef && isCapturedBy(D, Init);
bool locIsByrefHeader = !capturedByInit;
const Address Loc =
locIsByrefHeader ? emission.getObjectAddress(*this) : emission.Addr;
// Note: constexpr already initializes everything correctly.
LangOptions::TrivialAutoVarInitKind trivialAutoVarInit =
getAutoVarInitKind(type, D);
auto initializeWhatIsTechnicallyUninitialized = [&](Address Loc) {
if (trivialAutoVarInit ==
LangOptions::TrivialAutoVarInitKind::Uninitialized)
return;
// Only initialize a __block's storage: we always initialize the header.
if (emission.IsEscapingByRef && !locIsByrefHeader)
Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
return emitZeroOrPatternForAutoVarInit(type, D, Loc);
};
if (isTrivialInitializer(Init))
return initializeWhatIsTechnicallyUninitialized(Loc);
llvm::Constant *constant = nullptr;
if (emission.ConstantAggregateInitializer ||
D.mightBeUsableInConstantExpressions(getContext())) {
assert(!capturedByInit && "constant init contains a capturing block?");
if (emission.ConstantAggregateInitializer)
constant = emission.ConstantAggregateInitializer;
else
constant = ConstantEmitter(*this).tryEmitAbstractForInitializer(D);
if (constant && !constant->isNullValue() &&
(trivialAutoVarInit !=
LangOptions::TrivialAutoVarInitKind::Uninitialized)) {
IsPattern isPattern =
(trivialAutoVarInit == LangOptions::TrivialAutoVarInitKind::Pattern)
? IsPattern::Yes
: IsPattern::No;
// C guarantees that brace-init with fewer initializers than members in
// the aggregate will initialize the rest of the aggregate as-if it were
// static initialization. In turn static initialization guarantees that
// padding is initialized to zero bits. We could instead pattern-init if D
// has any ImplicitValueInitExpr, but that seems to be unintuitive
// behavior.
constant = constWithPadding(CGM, IsPattern::No,
replaceUndef(CGM, isPattern, constant));
}
if (constant && type->isBitIntType() &&
CGM.getTypes().typeRequiresSplitIntoByteArray(type)) {
// Constants for long _BitInt types are split into individual bytes.
// Try to fold these back into an integer constant so it can be stored
// properly.
llvm::Type *LoadType =
CGM.getTypes().convertTypeForLoadStore(type, constant->getType());
constant = llvm::ConstantFoldLoadFromConst(
constant, LoadType, llvm::APInt::getZero(32), CGM.getDataLayout());
}
}
if (!constant) {
if (trivialAutoVarInit !=
LangOptions::TrivialAutoVarInitKind::Uninitialized) {
// At this point, we know D has an Init expression, but isn't a constant.
// - If D is not a scalar, auto-var-init conservatively (members may be
// left uninitialized by constructor Init expressions for example).
// - If D is a scalar, we only need to auto-var-init if there is a
// self-reference. Otherwise, the Init expression should be sufficient.
// It may be that the Init expression uses other uninitialized memory,
// but auto-var-init here would not help, as auto-init would get
// overwritten by Init.
if (!type->isScalarType() || capturedByInit || isAccessedBy(D, Init)) {
initializeWhatIsTechnicallyUninitialized(Loc);
}
}
LValue lv = MakeAddrLValue(Loc, type);
lv.setNonGC(true);
return EmitExprAsInit(Init, &D, lv, capturedByInit);
}
PGO->markStmtMaybeUsed(Init);
if (!emission.ConstantAggregateInitializer) {
// For simple scalar/complex initialization, store the value directly.
LValue lv = MakeAddrLValue(Loc, type);
lv.setNonGC(true);
return EmitStoreThroughLValue(RValue::get(constant), lv, true);
}
emitStoresForConstant(D, Loc.withElementType(CGM.Int8Ty),
type.isVolatileQualified(), constant,
/*IsAutoInit=*/false);
}
void CodeGenFunction::MaybeEmitDeferredVarDeclInit(const VarDecl *VD) {
if (auto *DD = dyn_cast_if_present<DecompositionDecl>(VD)) {
for (auto *B : DD->flat_bindings())
if (auto *HD = B->getHoldingVar())
EmitVarDecl(*HD);
}
}
/// Emit an expression as an initializer for an object (variable, field, etc.)
/// at the given location. The expression is not necessarily the normal
/// initializer for the object, and the address is not necessarily
/// its normal location.
///
/// \param init the initializing expression
/// \param D the object to act as if we're initializing
/// \param lvalue the lvalue to initialize
/// \param capturedByInit true if \p D is a __block variable
/// whose address is potentially changed by the initializer
void CodeGenFunction::EmitExprAsInit(const Expr *init, const ValueDecl *D,
LValue lvalue, bool capturedByInit) {
QualType type = D->getType();
if (type->isReferenceType()) {
RValue rvalue = EmitReferenceBindingToExpr(init);
if (capturedByInit)
drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
EmitStoreThroughLValue(rvalue, lvalue, true);
return;
}
switch (getEvaluationKind(type)) {
case TEK_Scalar:
EmitScalarInit(init, D, lvalue, capturedByInit);
return;
case TEK_Complex: {
ComplexPairTy complex = EmitComplexExpr(init);
if (capturedByInit)
drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
EmitStoreOfComplex(complex, lvalue, /*init*/ true);
return;
}
case TEK_Aggregate:
if (type->isAtomicType()) {
EmitAtomicInit(const_cast<Expr*>(init), lvalue);
} else {
AggValueSlot::Overlap_t Overlap = AggValueSlot::MayOverlap;
if (isa<VarDecl>(D))
Overlap = AggValueSlot::DoesNotOverlap;
else if (auto *FD = dyn_cast<FieldDecl>(D))
Overlap = getOverlapForFieldInit(FD);
// TODO: how can we delay here if D is captured by its initializer?
EmitAggExpr(init,
AggValueSlot::forLValue(lvalue, AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased, Overlap));
}
return;
}
llvm_unreachable("bad evaluation kind");
}
/// Enter a destroy cleanup for the given local variable.
void CodeGenFunction::emitAutoVarTypeCleanup(
const CodeGenFunction::AutoVarEmission &emission,
QualType::DestructionKind dtorKind) {
assert(dtorKind != QualType::DK_none);
// Note that for __block variables, we want to destroy the
// original stack object, not the possibly forwarded object.
Address addr = emission.getObjectAddress(*this);
const VarDecl *var = emission.Variable;
QualType type = var->getType();
CleanupKind cleanupKind = NormalAndEHCleanup;
CodeGenFunction::Destroyer *destroyer = nullptr;
switch (dtorKind) {
case QualType::DK_none:
llvm_unreachable("no cleanup for trivially-destructible variable");
case QualType::DK_cxx_destructor:
// If there's an NRVO flag on the emission, we need a different
// cleanup.
if (emission.NRVOFlag) {
assert(!type->isArrayType());
CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
EHStack.pushCleanup<DestroyNRVOVariableCXX>(cleanupKind, addr, type, dtor,
emission.NRVOFlag);
return;
}
break;
case QualType::DK_objc_strong_lifetime:
// Suppress cleanups for pseudo-strong variables.
if (var->isARCPseudoStrong()) return;
// Otherwise, consider whether to use an EH cleanup or not.
cleanupKind = getARCCleanupKind();
// Use the imprecise destroyer by default.
if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
destroyer = CodeGenFunction::destroyARCStrongImprecise;
break;
case QualType::DK_objc_weak_lifetime:
break;
case QualType::DK_nontrivial_c_struct:
destroyer = CodeGenFunction::destroyNonTrivialCStruct;
if (emission.NRVOFlag) {
assert(!type->isArrayType());
EHStack.pushCleanup<DestroyNRVOVariableC>(cleanupKind, addr,
emission.NRVOFlag, type);
return;
}
break;
}
// If we haven't chosen a more specific destroyer, use the default.
if (!destroyer) destroyer = getDestroyer(dtorKind);
// Use an EH cleanup in array destructors iff the destructor itself
// is being pushed as an EH cleanup.
bool useEHCleanup = (cleanupKind & EHCleanup);
EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
useEHCleanup);
}
void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
assert(emission.Variable && "emission was not valid!");
// If this was emitted as a global constant, we're done.
if (emission.wasEmittedAsGlobal()) return;
// If we don't have an insertion point, we're done. Sema prevents
// us from jumping into any of these scopes anyway.
if (!HaveInsertPoint()) return;
const VarDecl &D = *emission.Variable;
// Check the type for a cleanup.
if (QualType::DestructionKind dtorKind = D.needsDestruction(getContext())) {
// Check if we're in a SEH block with /EH, prevent it
if (getLangOpts().CXXExceptions && currentFunctionUsesSEHTry())
getContext().getDiagnostics().Report(D.getLocation(),
diag::err_seh_object_unwinding);
emitAutoVarTypeCleanup(emission, dtorKind);
}
// In GC mode, honor objc_precise_lifetime.
if (getLangOpts().getGC() != LangOptions::NonGC &&
D.hasAttr<ObjCPreciseLifetimeAttr>()) {
EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
}
// Handle the cleanup attribute.
if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
const FunctionDecl *FD = CA->getFunctionDecl();
llvm::Constant *F = CGM.GetAddrOfFunction(FD);
assert(F && "Could not find function!");
const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D,
CA);
}
// If this is a block variable, call _Block_object_destroy
// (on the unforwarded address). Don't enter this cleanup if we're in pure-GC
// mode.
if (emission.IsEscapingByRef &&
CGM.getLangOpts().getGC() != LangOptions::GCOnly) {
BlockFieldFlags Flags = BLOCK_FIELD_IS_BYREF;
if (emission.Variable->getType().isObjCGCWeak())
Flags |= BLOCK_FIELD_IS_WEAK;
enterByrefCleanup(NormalAndEHCleanup, emission.Addr, Flags,
/*LoadBlockVarAddr*/ false,
cxxDestructorCanThrow(emission.Variable->getType()));
}
}
CodeGenFunction::Destroyer *
CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
switch (kind) {
case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
case QualType::DK_cxx_destructor:
return destroyCXXObject;
case QualType::DK_objc_strong_lifetime:
return destroyARCStrongPrecise;
case QualType::DK_objc_weak_lifetime:
return destroyARCWeak;
case QualType::DK_nontrivial_c_struct:
return destroyNonTrivialCStruct;
}
llvm_unreachable("Unknown DestructionKind");
}
/// pushEHDestroy - Push the standard destructor for the given type as
/// an EH-only cleanup.
void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
Address addr, QualType type) {
assert(dtorKind && "cannot push destructor for trivial type");
assert(needsEHCleanup(dtorKind));
pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
}
/// pushDestroy - Push the standard destructor for the given type as
/// at least a normal cleanup.
void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
Address addr, QualType type) {
assert(dtorKind && "cannot push destructor for trivial type");
CleanupKind cleanupKind = getCleanupKind(dtorKind);
pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
cleanupKind & EHCleanup);
}
void CodeGenFunction::pushLifetimeExtendedDestroy(
QualType::DestructionKind dtorKind, Address addr, QualType type) {
CleanupKind cleanupKind = getCleanupKind(dtorKind);
pushLifetimeExtendedDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
cleanupKind & EHCleanup);
}
void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, Address addr,
QualType type, Destroyer *destroyer,
bool useEHCleanupForArray) {
pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
useEHCleanupForArray);
}
// Pushes a destroy and defers its deactivation until its
// CleanupDeactivationScope is exited.
void CodeGenFunction::pushDestroyAndDeferDeactivation(
QualType::DestructionKind dtorKind, Address addr, QualType type) {
assert(dtorKind && "cannot push destructor for trivial type");
CleanupKind cleanupKind = getCleanupKind(dtorKind);
pushDestroyAndDeferDeactivation(
cleanupKind, addr, type, getDestroyer(dtorKind), cleanupKind & EHCleanup);
}
void CodeGenFunction::pushDestroyAndDeferDeactivation(
CleanupKind cleanupKind, Address addr, QualType type, Destroyer *destroyer,
bool useEHCleanupForArray) {
llvm::Instruction *DominatingIP =
Builder.CreateFlagLoad(llvm::Constant::getNullValue(Int8PtrTy));
pushDestroy(cleanupKind, addr, type, destroyer, useEHCleanupForArray);
DeferredDeactivationCleanupStack.push_back(
{EHStack.stable_begin(), DominatingIP});
}
void CodeGenFunction::pushStackRestore(CleanupKind Kind, Address SPMem) {
EHStack.pushCleanup<CallStackRestore>(
static_cast<CleanupKind>(Kind | StackRestore), SPMem);
}
void CodeGenFunction::pushKmpcAllocFree(
CleanupKind Kind, std::pair<llvm::Value *, llvm::Value *> AddrSizePair) {
EHStack.pushCleanup<KmpcAllocFree>(Kind, AddrSizePair);
}
void CodeGenFunction::pushLifetimeExtendedDestroy(CleanupKind cleanupKind,
Address addr, QualType type,
Destroyer *destroyer,
bool useEHCleanupForArray) {
// If we're not in a conditional branch, we don't need to bother generating a
// conditional cleanup.
if (!isInConditionalBranch()) {
// FIXME: When popping normal cleanups, we need to keep this EH cleanup
// around in case a temporary's destructor throws an exception.
// Add the cleanup to the EHStack. After the full-expr, this would be
// deactivated before being popped from the stack.
pushDestroyAndDeferDeactivation(cleanupKind, addr, type, destroyer,
useEHCleanupForArray);
// Since this is lifetime-extended, push it once again to the EHStack after
// the full expression.
return pushCleanupAfterFullExprWithActiveFlag<DestroyObject>(
cleanupKind, Address::invalid(), addr, type, destroyer,
useEHCleanupForArray);
}
// Otherwise, we should only destroy the object if it's been initialized.
using ConditionalCleanupType =
EHScopeStack::ConditionalCleanup<DestroyObject, Address, QualType,
Destroyer *, bool>;
DominatingValue<Address>::saved_type SavedAddr = saveValueInCond(addr);
// Remember to emit cleanup if we branch-out before end of full-expression
// (eg: through stmt-expr or coro suspensions).
AllocaTrackerRAII DeactivationAllocas(*this);
Address ActiveFlagForDeactivation = createCleanupActiveFlag();
pushCleanupAndDeferDeactivation<ConditionalCleanupType>(
cleanupKind, SavedAddr, type, destroyer, useEHCleanupForArray);
initFullExprCleanupWithFlag(ActiveFlagForDeactivation);
EHCleanupScope &cleanup = cast<EHCleanupScope>(*EHStack.begin());
// Erase the active flag if the cleanup was not emitted.
cleanup.AddAuxAllocas(std::move(DeactivationAllocas).Take());
// Since this is lifetime-extended, push it once again to the EHStack after
// the full expression.
// The previous active flag would always be 'false' due to forced deferred
// deactivation. Use a separate flag for lifetime-extension to correctly
// remember if this branch was taken and the object was initialized.
Address ActiveFlagForLifetimeExt = createCleanupActiveFlag();
pushCleanupAfterFullExprWithActiveFlag<ConditionalCleanupType>(
cleanupKind, ActiveFlagForLifetimeExt, SavedAddr, type, destroyer,
useEHCleanupForArray);
}
/// emitDestroy - Immediately perform the destruction of the given
/// object.
///
/// \param addr - the address of the object; a type*
/// \param type - the type of the object; if an array type, all
/// objects are destroyed in reverse order
/// \param destroyer - the function to call to destroy individual
/// elements
/// \param useEHCleanupForArray - whether an EH cleanup should be
/// used when destroying array elements, in case one of the
/// destructions throws an exception
void CodeGenFunction::emitDestroy(Address addr, QualType type,
Destroyer *destroyer,
bool useEHCleanupForArray) {
const ArrayType *arrayType = getContext().getAsArrayType(type);
if (!arrayType)
return destroyer(*this, addr, type);
llvm::Value *length = emitArrayLength(arrayType, type, addr);
CharUnits elementAlign =
addr.getAlignment()
.alignmentOfArrayElement(getContext().getTypeSizeInChars(type));
// Normally we have to check whether the array is zero-length.
bool checkZeroLength = true;
// But if the array length is constant, we can suppress that.
if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
// ...and if it's constant zero, we can just skip the entire thing.
if (constLength->isZero()) return;
checkZeroLength = false;
}
llvm::Value *begin = addr.emitRawPointer(*this);
llvm::Value *end =
Builder.CreateInBoundsGEP(addr.getElementType(), begin, length);
emitArrayDestroy(begin, end, type, elementAlign, destroyer,
checkZeroLength, useEHCleanupForArray);
}
/// emitArrayDestroy - Destroys all the elements of the given array,
/// beginning from last to first. The array cannot be zero-length.
///
/// \param begin - a type* denoting the first element of the array
/// \param end - a type* denoting one past the end of the array
/// \param elementType - the element type of the array
/// \param destroyer - the function to call to destroy elements
/// \param useEHCleanup - whether to push an EH cleanup to destroy
/// the remaining elements in case the destruction of a single
/// element throws
void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
llvm::Value *end,
QualType elementType,
CharUnits elementAlign,
Destroyer *destroyer,
bool checkZeroLength,
bool useEHCleanup) {
assert(!elementType->isArrayType());
// The basic structure here is a do-while loop, because we don't
// need to check for the zero-element case.
llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
if (checkZeroLength) {
llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
"arraydestroy.isempty");
Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
}
// Enter the loop body, making that address the current address.
llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
EmitBlock(bodyBB);
llvm::PHINode *elementPast =
Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
elementPast->addIncoming(end, entryBB);
// Shift the address back by one element.
llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
llvm::Type *llvmElementType = ConvertTypeForMem(elementType);
llvm::Value *element = Builder.CreateInBoundsGEP(
llvmElementType, elementPast, negativeOne, "arraydestroy.element");
if (useEHCleanup)
pushRegularPartialArrayCleanup(begin, element, elementType, elementAlign,
destroyer);
// Perform the actual destruction there.
destroyer(*this, Address(element, llvmElementType, elementAlign),
elementType);
if (useEHCleanup)
PopCleanupBlock();
// Check whether we've reached the end.
llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
Builder.CreateCondBr(done, doneBB, bodyBB);
elementPast->addIncoming(element, Builder.GetInsertBlock());
// Done.
EmitBlock(doneBB);
}
/// Perform partial array destruction as if in an EH cleanup. Unlike
/// emitArrayDestroy, the element type here may still be an array type.
static void emitPartialArrayDestroy(CodeGenFunction &CGF,
llvm::Value *begin, llvm::Value *end,
QualType type, CharUnits elementAlign,
CodeGenFunction::Destroyer *destroyer) {
llvm::Type *elemTy = CGF.ConvertTypeForMem(type);
// If the element type is itself an array, drill down.
unsigned arrayDepth = 0;
while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
// VLAs don't require a GEP index to walk into.
if (!isa<VariableArrayType>(arrayType))
arrayDepth++;
type = arrayType->getElementType();
}
if (arrayDepth) {
llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
SmallVector<llvm::Value*,4> gepIndices(arrayDepth+1, zero);
begin = CGF.Builder.CreateInBoundsGEP(
elemTy, begin, gepIndices, "pad.arraybegin");
end = CGF.Builder.CreateInBoundsGEP(
elemTy, end, gepIndices, "pad.arrayend");
}
// Destroy the array. We don't ever need an EH cleanup because we
// assume that we're in an EH cleanup ourselves, so a throwing
// destructor causes an immediate terminate.
CGF.emitArrayDestroy(begin, end, type, elementAlign, destroyer,
/*checkZeroLength*/ true, /*useEHCleanup*/ false);
}
namespace {
/// RegularPartialArrayDestroy - a cleanup which performs a partial
/// array destroy where the end pointer is regularly determined and
/// does not need to be loaded from a local.
class RegularPartialArrayDestroy final : public EHScopeStack::Cleanup {
llvm::Value *ArrayBegin;
llvm::Value *ArrayEnd;
QualType ElementType;
CodeGenFunction::Destroyer *Destroyer;
CharUnits ElementAlign;
public:
RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
QualType elementType, CharUnits elementAlign,
CodeGenFunction::Destroyer *destroyer)
: ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
ElementType(elementType), Destroyer(destroyer),
ElementAlign(elementAlign) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
ElementType, ElementAlign, Destroyer);
}
};
/// IrregularPartialArrayDestroy - a cleanup which performs a
/// partial array destroy where the end pointer is irregularly
/// determined and must be loaded from a local.
class IrregularPartialArrayDestroy final : public EHScopeStack::Cleanup {
llvm::Value *ArrayBegin;
Address ArrayEndPointer;
QualType ElementType;
CodeGenFunction::Destroyer *Destroyer;
CharUnits ElementAlign;
public:
IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
Address arrayEndPointer,
QualType elementType,
CharUnits elementAlign,
CodeGenFunction::Destroyer *destroyer)
: ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
ElementType(elementType), Destroyer(destroyer),
ElementAlign(elementAlign) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
ElementType, ElementAlign, Destroyer);
}
};
} // end anonymous namespace
/// pushIrregularPartialArrayCleanup - Push a NormalAndEHCleanup to
/// destroy already-constructed elements of the given array. The cleanup may be
/// popped with DeactivateCleanupBlock or PopCleanupBlock.
///
/// \param elementType - the immediate element type of the array;
/// possibly still an array type
void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
Address arrayEndPointer,
QualType elementType,
CharUnits elementAlign,
Destroyer *destroyer) {
pushFullExprCleanup<IrregularPartialArrayDestroy>(
NormalAndEHCleanup, arrayBegin, arrayEndPointer, elementType,
elementAlign, destroyer);
}
/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
/// already-constructed elements of the given array. The cleanup
/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
///
/// \param elementType - the immediate element type of the array;
/// possibly still an array type
void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
llvm::Value *arrayEnd,
QualType elementType,
CharUnits elementAlign,
Destroyer *destroyer) {
pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
arrayBegin, arrayEnd,
elementType, elementAlign,
destroyer);
}
/// Lazily declare the @llvm.lifetime.start intrinsic.
llvm::Function *CodeGenModule::getLLVMLifetimeStartFn() {
if (LifetimeStartFn)
return LifetimeStartFn;
LifetimeStartFn = llvm::Intrinsic::getOrInsertDeclaration(
&getModule(), llvm::Intrinsic::lifetime_start, AllocaInt8PtrTy);
return LifetimeStartFn;
}
/// Lazily declare the @llvm.lifetime.end intrinsic.
llvm::Function *CodeGenModule::getLLVMLifetimeEndFn() {
if (LifetimeEndFn)
return LifetimeEndFn;
LifetimeEndFn = llvm::Intrinsic::getOrInsertDeclaration(
&getModule(), llvm::Intrinsic::lifetime_end, AllocaInt8PtrTy);
return LifetimeEndFn;
}
/// Lazily declare the @llvm.fake.use intrinsic.
llvm::Function *CodeGenModule::getLLVMFakeUseFn() {
if (FakeUseFn)
return FakeUseFn;
FakeUseFn = llvm::Intrinsic::getOrInsertDeclaration(
&getModule(), llvm::Intrinsic::fake_use);
return FakeUseFn;
}
namespace {
/// A cleanup to perform a release of an object at the end of a
/// function. This is used to balance out the incoming +1 of a
/// ns_consumed argument when we can't reasonably do that just by
/// not doing the initial retain for a __block argument.
struct ConsumeARCParameter final : EHScopeStack::Cleanup {
ConsumeARCParameter(llvm::Value *param,
ARCPreciseLifetime_t precise)
: Param(param), Precise(precise) {}
llvm::Value *Param;
ARCPreciseLifetime_t Precise;
void Emit(CodeGenFunction &CGF, Flags flags) override {
CGF.EmitARCRelease(Param, Precise);
}
};
} // end anonymous namespace
/// Emit an alloca (or GlobalValue depending on target)
/// for the specified parameter and set up LocalDeclMap.
void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
unsigned ArgNo) {
bool NoDebugInfo = false;
// FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
"Invalid argument to EmitParmDecl");
// Set the name of the parameter's initial value to make IR easier to
// read. Don't modify the names of globals.
if (!isa<llvm::GlobalValue>(Arg.getAnyValue()))
Arg.getAnyValue()->setName(D.getName());
QualType Ty = D.getType();
assert((getLangOpts().OpenCL || Ty.getAddressSpace() == LangAS::Default) &&
"parameter has non-default address space in non-OpenCL mode");
// Use better IR generation for certain implicit parameters.
if (auto IPD = dyn_cast<ImplicitParamDecl>(&D)) {
// The only implicit argument a block has is its literal.
// This may be passed as an inalloca'ed value on Windows x86.
if (BlockInfo) {
llvm::Value *V = Arg.isIndirect()
? Builder.CreateLoad(Arg.getIndirectAddress())
: Arg.getDirectValue();
setBlockContextParameter(IPD, ArgNo, V);
return;
}
// Suppressing debug info for ThreadPrivateVar parameters, else it hides
// debug info of TLS variables.
NoDebugInfo =
(IPD->getParameterKind() == ImplicitParamKind::ThreadPrivateVar);
}
Address DeclPtr = Address::invalid();
RawAddress AllocaPtr = Address::invalid();
bool DoStore = false;
bool IsScalar = hasScalarEvaluationKind(Ty);
bool UseIndirectDebugAddress = false;
// If we already have a pointer to the argument, reuse the input pointer.
if (Arg.isIndirect()) {
DeclPtr = Arg.getIndirectAddress();
DeclPtr = DeclPtr.withElementType(ConvertTypeForMem(Ty));
auto *V = DeclPtr.emitRawPointer(*this);
AllocaPtr = RawAddress(V, DeclPtr.getElementType(), DeclPtr.getAlignment());
// For truly ABI indirect arguments -- those that are not `byval` -- store
// the address of the argument on the stack to preserve debug information.
ABIArgInfo ArgInfo = CurFnInfo->arguments()[ArgNo - 1].info;
if (ArgInfo.isIndirect())
UseIndirectDebugAddress = !ArgInfo.getIndirectByVal();
if (UseIndirectDebugAddress) {
auto PtrTy = getContext().getPointerType(Ty);
AllocaPtr = CreateMemTempWithoutCast(
PtrTy, getContext().getTypeAlignInChars(PtrTy),
D.getName() + ".indirect_addr");
EmitStoreOfScalar(V, AllocaPtr, /* Volatile */ false, PtrTy);
}
LangAS DestLangAS = Ty.getAddressSpace();
unsigned DestAS = getContext().getTargetAddressSpace(DestLangAS);
if (DeclPtr.getAddressSpace() != DestAS) {
auto *T = llvm::PointerType::get(getLLVMContext(), DestAS);
DeclPtr = DeclPtr.withPointer(performAddrSpaceCast(V, T),
DeclPtr.isKnownNonNull());
}
// Push a destructor cleanup for this parameter if the ABI requires it.
// Don't push a cleanup in a thunk for a method that will also emit a
// cleanup.
if (Ty->isRecordType() && !CurFuncIsThunk &&
Ty->castAsRecordDecl()->isParamDestroyedInCallee()) {
if (QualType::DestructionKind DtorKind =
D.needsDestruction(getContext())) {
assert((DtorKind == QualType::DK_cxx_destructor ||
DtorKind == QualType::DK_nontrivial_c_struct) &&
"unexpected destructor type");
pushDestroy(DtorKind, DeclPtr, Ty);
CalleeDestructedParamCleanups[cast<ParmVarDecl>(&D)] =
EHStack.stable_begin();
}
}
} else {
// Check if the parameter address is controlled by OpenMP runtime.
Address OpenMPLocalAddr =
getLangOpts().OpenMP
? CGM.getOpenMPRuntime().getAddressOfLocalVariable(*this, &D)
: Address::invalid();
if (getLangOpts().OpenMP && OpenMPLocalAddr.isValid()) {
DeclPtr = OpenMPLocalAddr;
AllocaPtr = DeclPtr;
} else {
// Otherwise, create a casted temporary to hold the value.
DeclPtr = CreateMemTemp(Ty, getContext().getDeclAlign(&D),
D.getName() + ".addr", &AllocaPtr);
}
DoStore = true;
}
llvm::Value *ArgVal = (DoStore ? Arg.getDirectValue() : nullptr);
LValue lv = MakeAddrLValue(DeclPtr, Ty);
// If this is a thunk, don't bother with ARC lifetime management.
// The true implementation will take care of that.
if (IsScalar && !CurFuncIsThunk) {
Qualifiers qs = Ty.getQualifiers();
if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
// We honor __attribute__((ns_consumed)) for types with lifetime.
// For __strong, it's handled by just skipping the initial retain;
// otherwise we have to balance out the initial +1 with an extra
// cleanup to do the release at the end of the function.
bool isConsumed = D.hasAttr<NSConsumedAttr>();
// If a parameter is pseudo-strong then we can omit the implicit retain.
if (D.isARCPseudoStrong()) {
assert(lt == Qualifiers::OCL_Strong &&
"pseudo-strong variable isn't strong?");
assert(qs.hasConst() && "pseudo-strong variable should be const!");
lt = Qualifiers::OCL_ExplicitNone;
}
// Load objects passed indirectly.
if (Arg.isIndirect() && !ArgVal)
ArgVal = Builder.CreateLoad(DeclPtr);
if (lt == Qualifiers::OCL_Strong) {
if (!isConsumed) {
if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
// use objc_storeStrong(&dest, value) for retaining the
// object. But first, store a null into 'dest' because
// objc_storeStrong attempts to release its old value.
llvm::Value *Null = CGM.EmitNullConstant(D.getType());
EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
EmitARCStoreStrongCall(lv.getAddress(), ArgVal, true);
DoStore = false;
}
else
// Don't use objc_retainBlock for block pointers, because we
// don't want to Block_copy something just because we got it
// as a parameter.
ArgVal = EmitARCRetainNonBlock(ArgVal);
}
} else {
// Push the cleanup for a consumed parameter.
if (isConsumed) {
ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
? ARCPreciseLifetime : ARCImpreciseLifetime);
EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), ArgVal,
precise);
}
if (lt == Qualifiers::OCL_Weak) {
EmitARCInitWeak(DeclPtr, ArgVal);
DoStore = false; // The weak init is a store, no need to do two.
}
}
// Enter the cleanup scope.
EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
}
}
// Store the initial value into the alloca.
if (DoStore)
EmitStoreOfScalar(ArgVal, lv, /* isInitialization */ true);
setAddrOfLocalVar(&D, DeclPtr);
// Push a FakeUse 'cleanup' object onto the EHStack for the parameter,
// which may be the 'this' pointer. This causes the emission of a fake.use
// call with the parameter as argument at the end of the function.
if (CGM.getCodeGenOpts().getExtendVariableLiveness() ==
CodeGenOptions::ExtendVariableLivenessKind::All ||
(CGM.getCodeGenOpts().getExtendVariableLiveness() ==
CodeGenOptions::ExtendVariableLivenessKind::This &&
&D == CXXABIThisDecl)) {
// We don't emit fake uses for coroutine parameters, other than `this`.
if (auto *FnDecl = dyn_cast_or_null<FunctionDecl>(CurCodeDecl);
&D == CXXABIThisDecl || !FnDecl || !FnDecl->getBody() ||
FnDecl->getBody()->getStmtClass() != Stmt::CoroutineBodyStmtClass) {
if (shouldExtendLifetime(getContext(), CurCodeDecl, D, CXXABIThisDecl))
EHStack.pushCleanup<FakeUse>(NormalFakeUse, DeclPtr);
}
}
// Emit debug info for param declarations in non-thunk functions.
if (CGDebugInfo *DI = getDebugInfo()) {
if (CGM.getCodeGenOpts().hasReducedDebugInfo() && !CurFuncIsThunk &&
!NoDebugInfo) {
llvm::DILocalVariable *DILocalVar = DI->EmitDeclareOfArgVariable(
&D, AllocaPtr.getPointer(), ArgNo, Builder, UseIndirectDebugAddress);
if (const auto *Var = dyn_cast_or_null<ParmVarDecl>(&D))
DI->getParamDbgMappings().insert({Var, DILocalVar});
}
}
if (D.hasAttr<AnnotateAttr>())
EmitVarAnnotations(&D, DeclPtr.emitRawPointer(*this));
// We can only check return value nullability if all arguments to the
// function satisfy their nullability preconditions. This makes it necessary
// to emit null checks for args in the function body itself.
if (requiresReturnValueNullabilityCheck()) {
auto Nullability = Ty->getNullability();
if (Nullability && *Nullability == NullabilityKind::NonNull) {
SanitizerScope SanScope(this);
RetValNullabilityPrecondition =
Builder.CreateAnd(RetValNullabilityPrecondition,
Builder.CreateIsNotNull(Arg.getAnyValue()));
}
}
}
void CodeGenModule::EmitOMPDeclareReduction(const OMPDeclareReductionDecl *D,
CodeGenFunction *CGF) {
if (!LangOpts.OpenMP || (!LangOpts.EmitAllDecls && !D->isUsed()))
return;
getOpenMPRuntime().emitUserDefinedReduction(CGF, D);
}
void CodeGenModule::EmitOMPDeclareMapper(const OMPDeclareMapperDecl *D,
CodeGenFunction *CGF) {
if (!LangOpts.OpenMP || LangOpts.OpenMPSimd ||
(!LangOpts.EmitAllDecls && !D->isUsed()))
return;
getOpenMPRuntime().emitUserDefinedMapper(D, CGF);
}
void CodeGenModule::EmitOpenACCDeclare(const OpenACCDeclareDecl *D,
CodeGenFunction *CGF) {
// This is a no-op, we cna just ignore these declarations.
}
void CodeGenModule::EmitOpenACCRoutine(const OpenACCRoutineDecl *D,
CodeGenFunction *CGF) {
// This is a no-op, we cna just ignore these declarations.
}
void CodeGenModule::EmitOMPRequiresDecl(const OMPRequiresDecl *D) {
getOpenMPRuntime().processRequiresDirective(D);
}
void CodeGenModule::EmitOMPAllocateDecl(const OMPAllocateDecl *D) {
for (const Expr *E : D->varlist()) {
const auto *DE = cast<DeclRefExpr>(E);
const auto *VD = cast<VarDecl>(DE->getDecl());
// Skip all but globals.
if (!VD->hasGlobalStorage())
continue;
// Check if the global has been materialized yet or not. If not, we are done
// as any later generation will utilize the OMPAllocateDeclAttr. However, if
// we already emitted the global we might have done so before the
// OMPAllocateDeclAttr was attached, leading to the wrong address space
// (potentially). While not pretty, common practise is to remove the old IR
// global and generate a new one, so we do that here too. Uses are replaced
// properly.
StringRef MangledName = getMangledName(VD);
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
if (!Entry)
continue;
// We can also keep the existing global if the address space is what we
// expect it to be, if not, it is replaced.
clang::LangAS GVAS = GetGlobalVarAddressSpace(VD);
auto TargetAS = getContext().getTargetAddressSpace(GVAS);
if (Entry->getType()->getAddressSpace() == TargetAS)
continue;
llvm::PointerType *PTy = llvm::PointerType::get(getLLVMContext(), TargetAS);
// Replace all uses of the old global with a cast. Since we mutate the type
// in place we neeed an intermediate that takes the spot of the old entry
// until we can create the cast.
llvm::GlobalVariable *DummyGV = new llvm::GlobalVariable(
getModule(), Entry->getValueType(), false,
llvm::GlobalValue::CommonLinkage, nullptr, "dummy", nullptr,
llvm::GlobalVariable::NotThreadLocal, Entry->getAddressSpace());
Entry->replaceAllUsesWith(DummyGV);
Entry->mutateType(PTy);
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getAddrSpaceCast(Entry, DummyGV->getType());
// Now we have a casted version of the changed global, the dummy can be
// replaced and deleted.
DummyGV->replaceAllUsesWith(NewPtrForOldDecl);
DummyGV->eraseFromParent();
}
}
std::optional<CharUnits>
CodeGenModule::getOMPAllocateAlignment(const VarDecl *VD) {
if (const auto *AA = VD->getAttr<OMPAllocateDeclAttr>()) {
if (Expr *Alignment = AA->getAlignment()) {
unsigned UserAlign =
Alignment->EvaluateKnownConstInt(getContext()).getExtValue();
CharUnits NaturalAlign =
getNaturalTypeAlignment(VD->getType().getNonReferenceType());
// OpenMP5.1 pg 185 lines 7-10
// Each item in the align modifier list must be aligned to the maximum
// of the specified alignment and the type's natural alignment.
return CharUnits::fromQuantity(
std::max<unsigned>(UserAlign, NaturalAlign.getQuantity()));
}
}
return std::nullopt;
}