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//===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-module state used while generating code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenModule.h"
#include "CGDebugInfo.h"
#include "CGObjCRuntime.h"
#include "Mangle.h"
#include "TargetInfo.h"
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#include "clang/CodeGen/CodeGenOptions.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
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#include "clang/AST/RecordLayout.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/ConvertUTF.h"
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#include "llvm/CallingConv.h"
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#include "llvm/Module.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/ADT/Triple.h"
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#include "llvm/Target/TargetData.h"
#include "llvm/Support/CallSite.h"
using namespace clang;
using namespace CodeGen;
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CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO,
llvm::Module &M, const llvm::TargetData &TD,
Diagnostic &diags)
: BlockModule(C, M, TD, Types, *this), Context(C),
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Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M),
TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags),
Types(C, M, TD, getTargetCodeGenInfo().getABIInfo()),
VTables(*this), Runtime(0), ABI(0),
CFConstantStringClassRef(0),
VMContext(M.getContext()) {
if (!Features.ObjC1)
Runtime = 0;
else if (!Features.NeXTRuntime)
Runtime = CreateGNUObjCRuntime(*this);
else if (Features.ObjCNonFragileABI)
Runtime = CreateMacNonFragileABIObjCRuntime(*this);
else
Runtime = CreateMacObjCRuntime(*this);
if (!Features.CPlusPlus)
ABI = 0;
else createCXXABI();
// If debug info generation is enabled, create the CGDebugInfo object.
DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0;
}
CodeGenModule::~CodeGenModule() {
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delete Runtime;
delete ABI;
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delete DebugInfo;
}
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void CodeGenModule::createObjCRuntime() {
if (!Features.NeXTRuntime)
Runtime = CreateGNUObjCRuntime(*this);
else if (Features.ObjCNonFragileABI)
Runtime = CreateMacNonFragileABIObjCRuntime(*this);
else
Runtime = CreateMacObjCRuntime(*this);
}
void CodeGenModule::createCXXABI() {
// For now, just create an Itanium ABI.
ABI = CreateItaniumCXXABI(*this);
}
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void CodeGenModule::Release() {
EmitDeferred();
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EmitCXXGlobalInitFunc();
if (Runtime)
if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction())
AddGlobalCtor(ObjCInitFunction);
EmitCtorList(GlobalCtors, "llvm.global_ctors");
EmitCtorList(GlobalDtors, "llvm.global_dtors");
EmitAnnotations();
EmitLLVMUsed();
bool CodeGenModule::isTargetDarwin() const {
return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin;
}
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
bool OmitOnError) {
if (OmitOnError && getDiags().hasErrorOccurred())
return;
unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
"cannot compile this %0 yet");
std::string Msg = Type;
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getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID)
<< Msg << S->getSourceRange();
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified decl yet.
void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type,
bool OmitOnError) {
if (OmitOnError && getDiags().hasErrorOccurred())
return;
unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
"cannot compile this %0 yet");
std::string Msg = Type;
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getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
CodeGenModule::getDeclVisibilityMode(const Decl *D) const {
if (const VarDecl *VD = dyn_cast<VarDecl>(D))
if (VD->getStorageClass() == VarDecl::PrivateExtern)
return LangOptions::Hidden;
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if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>()) {
switch (attr->getVisibility()) {
default: assert(0 && "Unknown visibility!");
case VisibilityAttr::DefaultVisibility:
return LangOptions::Default;
case VisibilityAttr::HiddenVisibility:
return LangOptions::Hidden;
case VisibilityAttr::ProtectedVisibility:
return LangOptions::Protected;
}
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// This decl should have the same visibility as its parent.
if (const DeclContext *DC = D->getDeclContext())
return getDeclVisibilityMode(cast<Decl>(DC));
return getLangOptions().getVisibilityMode();
void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
const Decl *D) const {
// Internal definitions always have default visibility.
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if (GV->hasLocalLinkage()) {
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
default: assert(0 && "Unknown visibility!");
case LangOptions::Default:
return GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
case LangOptions::Hidden:
return GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
case LangOptions::Protected:
return GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
void CodeGenModule::getMangledName(MangleBuffer &Buffer, GlobalDecl GD) {
const NamedDecl *ND = cast<NamedDecl>(GD.getDecl());
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if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND))
return getMangledCXXCtorName(Buffer, D, GD.getCtorType());
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if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND))
return getMangledCXXDtorName(Buffer, D, GD.getDtorType());
if (!getMangleContext().shouldMangleDeclName(ND)) {
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assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
Buffer.setString(ND->getNameAsCString());
return;
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}
getMangleContext().mangleName(ND, Buffer.getBuffer());
llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) {
return getModule().getNamedValue(Name);
}
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/// AddGlobalCtor - Add a function to the list that will be called before
/// main() runs.
void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) {
// FIXME: Type coercion of void()* types.
GlobalCtors.push_back(std::make_pair(Ctor, Priority));
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}
/// AddGlobalDtor - Add a function to the list that will be called
/// when the module is unloaded.
void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) {
// FIXME: Type coercion of void()* types.
GlobalDtors.push_back(std::make_pair(Dtor, Priority));
}
void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
// Ctor function type is void()*.
llvm::FunctionType* CtorFTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
std::vector<const llvm::Type*>(),
false);
llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy);
// Get the type of a ctor entry, { i32, void ()* }.
llvm::StructType* CtorStructTy =
llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext),
llvm::PointerType::getUnqual(CtorFTy), NULL);
// Construct the constructor and destructor arrays.
std::vector<llvm::Constant*> Ctors;
for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
std::vector<llvm::Constant*> S;
S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy));
Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S));
}
if (!Ctors.empty()) {
llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size());
new llvm::GlobalVariable(TheModule, AT, false,
llvm::GlobalValue::AppendingLinkage,
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}
}
void CodeGenModule::EmitAnnotations() {
if (Annotations.empty())
return;
// Create a new global variable for the ConstantStruct in the Module.
llvm::Constant *Array =
llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(),
Annotations.size()),
Annotations);
llvm::GlobalValue *gv =
new llvm::GlobalVariable(TheModule, Array->getType(), false,
llvm::GlobalValue::AppendingLinkage, Array,
gv->setSection("llvm.metadata");
}
static CodeGenModule::GVALinkage
GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
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const LangOptions &Features) {
CodeGenModule::GVALinkage External = CodeGenModule::GVA_StrongExternal;
Linkage L = FD->getLinkage();
if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
FD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return CodeGenModule::GVA_Internal;
case ExternalLinkage:
switch (FD->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
External = CodeGenModule::GVA_StrongExternal;
break;
case TSK_ExplicitInstantiationDefinition:
return CodeGenModule::GVA_ExplicitTemplateInstantiation;
case TSK_ExplicitInstantiationDeclaration:
case TSK_ImplicitInstantiation:
External = CodeGenModule::GVA_TemplateInstantiation;
break;
}
}
if (!FD->isInlined())
return External;
if (!Features.CPlusPlus || FD->hasAttr<GNUInlineAttr>()) {
// GNU or C99 inline semantics. Determine whether this symbol should be
// externally visible.
if (FD->isInlineDefinitionExternallyVisible())
return External;
// C99 inline semantics, where the symbol is not externally visible.
return CodeGenModule::GVA_C99Inline;
// C++0x [temp.explicit]p9:
// [ Note: The intent is that an inline function that is the subject of
// an explicit instantiation declaration will still be implicitly
// instantiated when used so that the body can be considered for
// inlining, but that no out-of-line copy of the inline function would be
// generated in the translation unit. -- end note ]
if (FD->getTemplateSpecializationKind()
== TSK_ExplicitInstantiationDeclaration)
return CodeGenModule::GVA_C99Inline;
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return CodeGenModule::GVA_CXXInline;
llvm::GlobalValue::LinkageTypes
CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
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GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
if (Linkage == GVA_Internal) {
return llvm::Function::InternalLinkage;
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} else if (D->hasAttr<DLLExportAttr>()) {
return llvm::Function::DLLExportLinkage;
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} else if (D->hasAttr<WeakAttr>()) {
return llvm::Function::WeakAnyLinkage;
} else if (Linkage == GVA_C99Inline) {
// In C99 mode, 'inline' functions are guaranteed to have a strong
// definition somewhere else, so we can use available_externally linkage.
return llvm::Function::AvailableExternallyLinkage;
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} else if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) {
// In C++, the compiler has to emit a definition in every translation unit
// that references the function. We should use linkonce_odr because
// a) if all references in this translation unit are optimized away, we
// don't need to codegen it. b) if the function persists, it needs to be
// merged with other definitions. c) C++ has the ODR, so we know the
// definition is dependable.
return llvm::Function::LinkOnceODRLinkage;
} else if (Linkage == GVA_ExplicitTemplateInstantiation) {
// An explicit instantiation of a template has weak linkage, since
// explicit instantiations can occur in multiple translation units
// and must all be equivalent. However, we are not allowed to
// throw away these explicit instantiations.
return llvm::Function::WeakODRLinkage;
assert(Linkage == GVA_StrongExternal);
// Otherwise, we have strong external linkage.
return llvm::Function::ExternalLinkage;
}
/// SetFunctionDefinitionAttributes - Set attributes for a global.
///
/// FIXME: This is currently only done for aliases and functions, but not for
/// variables (these details are set in EmitGlobalVarDefinition for variables).
void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
llvm::GlobalValue *GV) {
void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
llvm::Function *F) {
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unsigned CallingConv;
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ConstructAttributeList(Info, D, AttributeList, CallingConv);
F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
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AttributeList.size()));
F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
}
void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
llvm::Function *F) {
if (!Features.Exceptions && !Features.ObjCNonFragileABI)
F->addFnAttr(llvm::Attribute::NoUnwind);
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if (D->hasAttr<AlwaysInlineAttr>())
F->addFnAttr(llvm::Attribute::AlwaysInline);
F->addFnAttr(llvm::Attribute::NoInline);
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if (Features.getStackProtectorMode() == LangOptions::SSPOn)
F->addFnAttr(llvm::Attribute::StackProtect);
else if (Features.getStackProtectorMode() == LangOptions::SSPReq)
F->addFnAttr(llvm::Attribute::StackProtectReq);
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>()) {
unsigned width = Context.Target.getCharWidth();
F->setAlignment(AA->getAlignment() / width);
while ((AA = AA->getNext<AlignedAttr>()))
F->setAlignment(std::max(F->getAlignment(), AA->getAlignment() / width));
}
// C++ ABI requires 2-byte alignment for member functions.
if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
F->setAlignment(2);
}
void CodeGenModule::SetCommonAttributes(const Decl *D,
llvm::GlobalValue *GV) {
setGlobalVisibility(GV, D);
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if (D->hasAttr<UsedAttr>())
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if (const SectionAttr *SA = D->getAttr<SectionAttr>())
GV->setSection(SA->getName());
getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this);
void CodeGenModule::SetInternalFunctionAttributes(const Decl *D,
llvm::Function *F,
const CGFunctionInfo &FI) {
SetLLVMFunctionAttributes(D, FI, F);
SetLLVMFunctionAttributesForDefinition(D, F);
F->setLinkage(llvm::Function::InternalLinkage);
SetCommonAttributes(D, F);
}
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void CodeGenModule::SetFunctionAttributes(GlobalDecl GD,
llvm::Function *F,
bool IsIncompleteFunction) {
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const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
if (!IsIncompleteFunction)
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SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F);
// Only a few attributes are set on declarations; these may later be
// overridden by a definition.
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if (FD->hasAttr<DLLImportAttr>()) {
F->setLinkage(llvm::Function::DLLImportLinkage);
} else if (FD->hasAttr<WeakAttr>() ||
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FD->hasAttr<WeakImportAttr>()) {
// "extern_weak" is overloaded in LLVM; we probably should have
F->setLinkage(llvm::Function::ExternalWeakLinkage);
} else {
F->setLinkage(llvm::Function::ExternalLinkage);
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if (const SectionAttr *SA = FD->getAttr<SectionAttr>())
F->setSection(SA->getName());
}
void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) {
"Only globals with definition can force usage.");
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LLVMUsed.push_back(GV);
}
void CodeGenModule::EmitLLVMUsed() {
// Don't create llvm.used if there is no need.
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if (LLVMUsed.empty())
return;
const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
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// Convert LLVMUsed to what ConstantArray needs.
std::vector<llvm::Constant*> UsedArray;
UsedArray.resize(LLVMUsed.size());
for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) {
UsedArray[i] =
llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]),
i8PTy);
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}
if (UsedArray.empty())
return;
llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size());
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(getModule(), ATy, false,
llvm::GlobalValue::AppendingLinkage,
GV->setSection("llvm.metadata");
}
void CodeGenModule::EmitDeferred() {
// Emit code for any potentially referenced deferred decls. Since a
// previously unused static decl may become used during the generation of code
// for a static function, iterate until no changes are made.
while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) {
if (!DeferredVTables.empty()) {
const CXXRecordDecl *RD = DeferredVTables.back();
DeferredVTables.pop_back();
getVTables().GenerateClassData(getVTableLinkage(RD), RD);
continue;
}
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GlobalDecl D = DeferredDeclsToEmit.back();
DeferredDeclsToEmit.pop_back();
// Check to see if we've already emitted this. This is necessary
// for a couple of reasons: first, decls can end up in the
// deferred-decls queue multiple times, and second, decls can end
// up with definitions in unusual ways (e.g. by an extern inline
// function acquiring a strong function redefinition). Just
// ignore these cases.
//
// TODO: That said, looking this up multiple times is very wasteful.
MangleBuffer Name;
getMangledName(Name, D);
llvm::GlobalValue *CGRef = GetGlobalValue(Name);
assert(CGRef && "Deferred decl wasn't referenced?");
if (!CGRef->isDeclaration())
continue;
// GlobalAlias::isDeclaration() defers to the aliasee, but for our
// purposes an alias counts as a definition.
if (isa<llvm::GlobalAlias>(CGRef))
continue;
// Otherwise, emit the definition and move on to the next one.
EmitGlobalDefinition(D);
}
/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the
/// annotation information for a given GlobalValue. The annotation struct is
/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the
/// GlobalValue being annotated. The second field is the constant string
/// created from the AnnotateAttr's annotation. The third field is a constant
/// string containing the name of the translation unit. The fourth field is
/// the line number in the file of the annotated value declaration.
///
/// FIXME: this does not unique the annotation string constants, as llvm-gcc
/// appears to.
///
llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
const AnnotateAttr *AA,
unsigned LineNo) {
llvm::Module *M = &getModule();
// get [N x i8] constants for the annotation string, and the filename string
// which are the 2nd and 3rd elements of the global annotation structure.
const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext);
llvm::Constant *anno = llvm::ConstantArray::get(VMContext,
AA->getAnnotation(), true);
llvm::Constant *unit = llvm::ConstantArray::get(VMContext,
M->getModuleIdentifier(),
true);
// Get the two global values corresponding to the ConstantArrays we just
// created to hold the bytes of the strings.
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new llvm::GlobalVariable(*M, anno->getType(), false,
llvm::GlobalValue::PrivateLinkage, anno,
GV->getName());
// translation unit name string, emitted into the llvm.metadata section.
llvm::GlobalValue *unitGV =
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new llvm::GlobalVariable(*M, unit->getType(), false,
llvm::GlobalValue::PrivateLinkage, unit,
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".str");
llvm::ConstantExpr::getBitCast(GV, SBP),
llvm::ConstantExpr::getBitCast(annoGV, SBP),
llvm::ConstantExpr::getBitCast(unitGV, SBP),
llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo)
return llvm::ConstantStruct::get(VMContext, Fields, 4, false);
bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
// Never defer when EmitAllDecls is specified or the decl has
// attribute used.
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if (Features.EmitAllDecls || Global->hasAttr<UsedAttr>())
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
// Constructors and destructors should never be deferred.
if (FD->hasAttr<ConstructorAttr>() ||
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FD->hasAttr<DestructorAttr>())
// The key function for a class must never be deferred.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Global)) {
const CXXRecordDecl *RD = MD->getParent();
if (MD->isOutOfLine() && RD->isDynamicClass()) {
const CXXMethodDecl *KeyFunction = getContext().getKeyFunction(RD);
if (KeyFunction &&
KeyFunction->getCanonicalDecl() == MD->getCanonicalDecl())
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GVALinkage Linkage = GetLinkageForFunction(getContext(), FD, Features);
// static, static inline, always_inline, and extern inline functions can
// always be deferred. Normal inline functions can be deferred in C99/C++.
// Implicit template instantiations can also be deferred in C++.
if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation)
return true;
return false;
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Invalid decl");
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// We never want to defer structs that have non-trivial constructors or
// destructors.
// FIXME: Handle references.
if (const RecordType *RT = VD->getType()->getAs<RecordType>()) {
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
if (!RD->hasTrivialConstructor() || !RD->hasTrivialDestructor())
return false;
}
}
// Static data may be deferred, but out-of-line static data members
// cannot be.
Linkage L = VD->getLinkage();
if (L == ExternalLinkage && getContext().getLangOptions().CPlusPlus &&
VD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
// Initializer has side effects?
if (VD->getInit() && VD->getInit()->HasSideEffects(Context))
return false;
return !(VD->isStaticDataMember() && VD->isOutOfLine());
case ExternalLinkage:
break;
llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
const AliasAttr *AA = VD->getAttr<AliasAttr>();
assert(AA && "No alias?");
const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
// See if there is already something with the target's name in the module.
llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
llvm::Constant *Aliasee;
if (isa<llvm::FunctionType>(DeclTy))
Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl());
Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
llvm::PointerType::getUnqual(DeclTy), 0);
if (!Entry) {
llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee);
F->setLinkage(llvm::Function::ExternalWeakLinkage);
WeakRefReferences.insert(F);
}
return Aliasee;
}
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
const ValueDecl *Global = cast<ValueDecl>(GD.getDecl());
// Weak references don't produce any output by themselves.
if (Global->hasAttr<WeakRefAttr>())
return;
// If this is an alias definition (which otherwise looks like a declaration)
// emit it now.
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if (Global->hasAttr<AliasAttr>())
return EmitAliasDefinition(GD);
// Ignore declarations, they will be emitted on their first use.
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
// Forward declarations are emitted lazily on first use.
if (!FD->isThisDeclarationADefinition())
return;
} else {
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
if (VD->isThisDeclarationADefinition() != VarDecl::Definition)
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}
// Defer code generation when possible if this is a static definition, inline
// function etc. These we only want to emit if they are used.
if (!MayDeferGeneration(Global)) {
// Emit the definition if it can't be deferred.
EmitGlobalDefinition(GD);
// If the value has already been used, add it directly to the
// DeferredDeclsToEmit list.
MangleBuffer MangledName;
getMangledName(MangledName, GD);
if (GetGlobalValue(MangledName))
DeferredDeclsToEmit.push_back(GD);
else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
// DeferredDeclsToEmit.
DeferredDecls[MangledName] = GD;
}
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}
void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
Context.getSourceManager(),
"Generating code for declaration");
if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
if (Method->isVirtual())
getVTables().EmitThunks(GD);
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if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
return EmitCXXConstructor(CD, GD.getCtorType());
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D))
return EmitCXXDestructor(DD, GD.getDtorType());
if (isa<FunctionDecl>(D))
return EmitGlobalFunctionDefinition(GD);
if (const VarDecl *VD = dyn_cast<VarDecl>(D))
return EmitGlobalVarDefinition(VD);
assert(0 && "Invalid argument to EmitGlobalDefinition()");
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/// GetOrCreateLLVMFunction - If the specified mangled name is not in the
/// module, create and return an llvm Function with the specified type. If there
/// is something in the module with the specified name, return it potentially
/// bitcasted to the right type.
///
/// If D is non-null, it specifies a decl that correspond to this. This is used
/// to set the attributes on the function when it is first created.
llvm::Constant *
CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName,
const llvm::Type *Ty,
GlobalDecl D) {
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
if (Entry) {
if (WeakRefReferences.count(Entry)) {
const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl());
if (FD && !FD->hasAttr<WeakAttr>())
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Entry->setLinkage(llvm::Function::ExternalLinkage);
if (Entry->getType()->getElementType() == Ty)
return Entry;
// Make sure the result is of the correct type.
const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
return llvm::ConstantExpr::getBitCast(Entry, PTy);
// This function doesn't have a complete type (for example, the return
// type is an incomplete struct). Use a fake type instead, and make
// sure not to try to set attributes.
bool IsIncompleteFunction = false;
const llvm::FunctionType *FTy;
if (isa<llvm::FunctionType>(Ty)) {
FTy = cast<llvm::FunctionType>(Ty);
} else {
FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
std::vector<const llvm::Type*>(), false);
IsIncompleteFunction = true;
}
llvm::Function *F = llvm::Function::Create(FTy,
llvm::Function::ExternalLinkage,
MangledName, &getModule());
assert(F->getName() == MangledName && "name was uniqued!");
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SetFunctionAttributes(D, F, IsIncompleteFunction);
// This is the first use or definition of a mangled name. If there is a
// deferred decl with this name, remember that we need to emit it at the end
// of the file.
llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName);
if (DDI != DeferredDecls.end()) {
// Move the potentially referenced deferred decl to the DeferredDeclsToEmit
// list, and remove it from DeferredDecls (since we don't need it anymore).
DeferredDeclsToEmit.push_back(DDI->second);
DeferredDecls.erase(DDI);
} else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) {
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// If this the first reference to a C++ inline function in a class, queue up
// the deferred function body for emission. These are not seen as
// top-level declarations.
if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD))
DeferredDeclsToEmit.push_back(D);
// A called constructor which has no definition or declaration need be
// synthesized.
else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
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if (CD->isImplicit()) {
assert(CD->isUsed() && "Sema doesn't consider constructor as used.");
DeferredDeclsToEmit.push_back(D);
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}
} else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) {
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if (DD->isImplicit()) {
assert(DD->isUsed() && "Sema doesn't consider destructor as used.");
DeferredDeclsToEmit.push_back(D);
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}
} else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
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if (MD->isCopyAssignment() && MD->isImplicit()) {
assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used.");
DeferredDeclsToEmit.push_back(D);
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}
}
// Make sure the result is of the requested type.
if (!IsIncompleteFunction) {
assert(F->getType()->getElementType() == Ty);
return F;
}
const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
return llvm::ConstantExpr::getBitCast(F, PTy);
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/// GetAddrOfFunction - Return the address of the given function. If Ty is
/// non-null, then this function will use the specified type if it has to
/// create it (this occurs when we see a definition of the function).
llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD,
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const llvm::Type *Ty) {
// If there was no specific requested type, just convert it now.
if (!Ty)
Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType());
MangleBuffer MangledName;
getMangledName(MangledName, GD);
return GetOrCreateLLVMFunction(MangledName, Ty, GD);
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}
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/// CreateRuntimeFunction - Create a new runtime function with the specified
/// type and name.
llvm::Constant *
CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy,
llvm::StringRef Name) {
return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl());
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}
static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) {
if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType())
return false;
if (Context.getLangOptions().CPlusPlus &&
Context.getBaseElementType(D->getType())->getAs<RecordType>()) {
// FIXME: We should do something fancier here!
return false;
}
return true;
}
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/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
/// create and return an llvm GlobalVariable with the specified type. If there
/// is something in the module with the specified name, return it potentially
/// bitcasted to the right type.
///
/// If D is non-null, it specifies a decl that correspond to this. This is used
/// to set the attributes on the global when it is first created.
llvm::Constant *
CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName,
const llvm::PointerType *Ty,
const VarDecl *D) {
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
if (WeakRefReferences.count(Entry)) {
if (D && !D->hasAttr<WeakAttr>())
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Entry->setLinkage(llvm::Function::ExternalLinkage);
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if (Entry->getType() == Ty)
return Entry;
// Make sure the result is of the correct type.
return llvm::ConstantExpr::getBitCast(Entry, Ty);
// This is the first use or definition of a mangled name. If there is a
// deferred decl with this name, remember that we need to emit it at the end
// of the file.
llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName);
if (DDI != DeferredDecls.end()) {
// Move the potentially referenced deferred decl to the DeferredDeclsToEmit
// list, and remove it from DeferredDecls (since we don't need it anymore).
DeferredDeclsToEmit.push_back(DDI->second);
DeferredDecls.erase(DDI);
}
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(getModule(), Ty->getElementType(), false,
0, MangledName, 0,
// Handle things which are present even on external declarations.
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if (D) {
// FIXME: This code is overly simple and should be merged with other global
// handling.
GV->setConstant(DeclIsConstantGlobal(Context, D));
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// FIXME: Merge with other attribute handling code.
if (D->getStorageClass() == VarDecl::PrivateExtern)
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
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D->hasAttr<WeakImportAttr>())
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GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
GV->setThreadLocal(D->isThreadSpecified());
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}
return GV;
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}
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/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
/// given global variable. If Ty is non-null and if the global doesn't exist,
/// then it will be greated with the specified type instead of whatever the
/// normal requested type would be.
llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
const llvm::Type *Ty) {
assert(D->hasGlobalStorage() && "Not a global variable");
QualType ASTTy = D->getType();
if (Ty == 0)
Ty = getTypes().ConvertTypeForMem(ASTTy);
llvm::PointerType::get(Ty, ASTTy.getAddressSpace());
MangleBuffer MangledName;
getMangledName(MangledName, D);
return GetOrCreateLLVMGlobal(MangledName, PTy, D);
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}
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/// CreateRuntimeVariable - Create a new runtime global variable with the
/// specified type and name.
llvm::Constant *
CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty,
llvm::StringRef Name) {
return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0);
void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
assert(!D->getInit() && "Cannot emit definite definitions here!");
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if (MayDeferGeneration(D)) {
// If we have not seen a reference to this variable yet, place it
// into the deferred declarations table to be emitted if needed
// later.
MangleBuffer MangledName;
getMangledName(MangledName, D);
if (!GetGlobalValue(MangledName)) {
DeferredDecls[MangledName] = D;
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}
}
// The tentative definition is the only definition.
EmitGlobalVarDefinition(D);
}
void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) {
if (DefinitionRequired)
getVTables().GenerateClassData(getVTableLinkage(Class), Class);
}
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llvm::GlobalVariable::LinkageTypes
CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
if (RD->isInAnonymousNamespace() || !RD->hasLinkage())
return llvm::GlobalVariable::InternalLinkage;
if (const CXXMethodDecl *KeyFunction
= RD->getASTContext().getKeyFunction(RD)) {
// If this class has a key function, use that to determine the linkage of
// the vtable.
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const FunctionDecl *Def = 0;
if (KeyFunction->getBody(Def))