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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 "clang/Frontend/CompileOptions.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclCXX.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"
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#include "llvm/Target/TargetData.h"
using namespace clang;
using namespace CodeGen;
CodeGenModule::CodeGenModule(ASTContext &C, const CompileOptions &compileOpts,
llvm::Module &M, const llvm::TargetData &TD,
Diagnostic &diags)
: BlockModule(C, M, TD, Types, *this), Context(C),
Features(C.getLangOptions()), CompileOpts(compileOpts), TheModule(M),
TheTargetData(TD), Diags(diags), Types(C, M, TD), Runtime(0),
MemCpyFn(0), MemMoveFn(0), MemSetFn(0), CFConstantStringClassRef(0) {
if (!Features.ObjC1)
Runtime = 0;
else if (!Features.NeXTRuntime)
Runtime = CreateGNUObjCRuntime(*this);
else if (Features.ObjCNonFragileABI)
Runtime = CreateMacNonFragileABIObjCRuntime(*this);
else
Runtime = CreateMacObjCRuntime(*this);
// If debug info generation is enabled, create the CGDebugInfo object.
DebugInfo = CompileOpts.DebugInfo ? new CGDebugInfo(this) : 0;
}
CodeGenModule::~CodeGenModule() {
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delete Runtime;
delete DebugInfo;
}
void CodeGenModule::Release() {
EmitDeferred();
if (Runtime)
if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction())
AddGlobalCtor(ObjCInitFunction);
EmitCtorList(GlobalCtors, "llvm.global_ctors");
EmitCtorList(GlobalDtors, "llvm.global_dtors");
EmitAnnotations();
EmitLLVMUsed();
/// 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;
LangOptions::VisibilityMode
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;
}
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);
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const char *CodeGenModule::getMangledName(const GlobalDecl &GD) {
const NamedDecl *ND = GD.getDecl();
if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND))
return getMangledCXXCtorName(D, GD.getCtorType());
if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND))
return getMangledCXXDtorName(D, GD.getDtorType());
return getMangledName(ND);
}
/// \brief Retrieves the mangled name for the given declaration.
///
/// If the given declaration requires a mangled name, returns an
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/// const char* containing the mangled name. Otherwise, returns
/// the unmangled name.
///
const char *CodeGenModule::getMangledName(const NamedDecl *ND) {
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// In C, functions with no attributes never need to be mangled. Fastpath them.
if (!getLangOptions().CPlusPlus && !ND->hasAttrs()) {
assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
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}
llvm::SmallString<256> Name;
llvm::raw_svector_ostream Out(Name);
if (!mangleName(ND, Context, Out)) {
assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
return UniqueMangledName(Name.begin(), Name.end());
}
const char *CodeGenModule::UniqueMangledName(const char *NameStart,
const char *NameEnd) {
assert(*(NameEnd - 1) == '\0' && "Mangled name must be null terminated!");
return MangledNames.GetOrCreateValue(NameStart, NameEnd).getKeyData();
}
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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::VoidTy,
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(llvm::Type::Int32Ty,
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::Int32Ty, I->second, false));
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.getContext(), AT, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(AT, Ctors),
GlobalName,
&TheModule);
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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.getContext(), Array->getType(), false,
llvm::GlobalValue::AppendingLinkage, Array,
"llvm.global.annotations", &TheModule);
gv->setSection("llvm.metadata");
}
static CodeGenModule::GVALinkage
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GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
const LangOptions &Features) {
// The kind of external linkage this function will have, if it is not
// inline or static.
CodeGenModule::GVALinkage External = CodeGenModule::GVA_StrongExternal;
if (Context.getLangOptions().CPlusPlus &&
(FD->getPrimaryTemplate() || FD->getInstantiatedFromMemberFunction()) &&
!FD->isExplicitSpecialization())
External = CodeGenModule::GVA_TemplateInstantiation;
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if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
// C++ member functions defined inside the class are always inline.
if (MD->isInline() || !MD->isOutOfLine())
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return CodeGenModule::GVA_CXXInline;
return External;
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}
// "static" functions get internal linkage.
if (FD->getStorageClass() == FunctionDecl::Static)
return CodeGenModule::GVA_Internal;
if (!FD->isInline())
return External;
// If the inline function explicitly has the GNU inline attribute on it, or if
// this is C89 mode, we use to GNU semantics.
if (!Features.C99 && !Features.CPlusPlus) {
// extern inline in GNU mode is like C99 inline.
if (FD->getStorageClass() == FunctionDecl::Extern)
return CodeGenModule::GVA_C99Inline;
// Normal inline is a strong symbol.
return CodeGenModule::GVA_StrongExternal;
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} else if (FD->hasActiveGNUInlineAttribute(Context)) {
// GCC in C99 mode seems to use a different decision-making
// process for extern inline, which factors in previous
// declarations.
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if (FD->isExternGNUInline(Context))
return CodeGenModule::GVA_C99Inline;
// Normal inline is a strong symbol.
return External;
// The definition of inline changes based on the language. Note that we
// have already handled "static inline" above, with the GVA_Internal case.
if (Features.CPlusPlus) // inline and extern inline.
return CodeGenModule::GVA_CXXInline;
assert(Features.C99 && "Must be in C99 mode if not in C89 or C++ mode");
if (FD->isC99InlineDefinition())
return CodeGenModule::GVA_C99Inline;
return CodeGenModule::GVA_StrongExternal;
}
/// 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) {
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GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
if (Linkage == GVA_Internal) {
GV->setLinkage(llvm::Function::InternalLinkage);
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} else if (D->hasAttr<DLLExportAttr>()) {
GV->setLinkage(llvm::Function::DLLExportLinkage);
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} else if (D->hasAttr<WeakAttr>()) {
GV->setLinkage(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.
GV->setLinkage(llvm::Function::AvailableExternallyLinkage);
} 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.
GV->setLinkage(llvm::Function::LinkOnceODRLinkage);
assert(Linkage == GVA_StrongExternal);
// Otherwise, we have strong external linkage.
GV->setLinkage(llvm::Function::ExternalLinkage);
void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
const CGFunctionInfo &Info,
llvm::Function *F) {
F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
AttributeList.size()));
// Set the appropriate calling convention for the Function.
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if (D->hasAttr<FastCallAttr>())
F->setCallingConv(llvm::CallingConv::X86_FastCall);
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if (D->hasAttr<StdCallAttr>())
F->setCallingConv(llvm::CallingConv::X86_StdCall);
}
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);
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if (D->hasAttr<NoinlineAttr>())
F->addFnAttr(llvm::Attribute::NoInline);
}
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());
}
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);
}
void CodeGenModule::SetFunctionAttributes(const FunctionDecl *FD,
llvm::Function *F,
bool IsIncompleteFunction) {
if (!IsIncompleteFunction)
SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(FD), 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);
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} else if (FD->hasAttr<WeakAttr>() ||
FD->hasAttr<WeakImportAttr>()) {
// "extern_weak" is overloaded in LLVM; we probably should have
// separate linkage types for this.
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) {
assert(!GV->isDeclaration() &&
"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.
// FIXME. Runtime indicates that there might be more 'used' symbols; but not
// necessariy. So, this test is not accurate for emptiness.
if (LLVMUsed.empty() && !Runtime)
return;
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llvm::Type *i8PTy = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
// 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);
}
if (Runtime)
Runtime->MergeMetadataGlobals(UsedArray);
if (UsedArray.empty())
return;
llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size());
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(getModule().getContext(), ATy, false,
llvm::GlobalValue::AppendingLinkage,
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llvm::ConstantArray::get(ATy, UsedArray),
"llvm.used", &getModule());
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()) {
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GlobalDecl D = DeferredDeclsToEmit.back();
DeferredDeclsToEmit.pop_back();
// The mangled name for the decl must have been emitted in GlobalDeclMap.
// Look it up to see if it was defined with a stronger definition (e.g. an
// extern inline function with a strong function redefinition). If so,
// just ignore the deferred decl.
llvm::GlobalValue *CGRef = GlobalDeclMap[getMangledName(D)];
assert(CGRef && "Deferred decl wasn't referenced?");
if (!CGRef->isDeclaration())
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::PointerType::getUnqual(llvm::Type::Int8Ty);
llvm::Constant *anno = llvm::ConstantArray::get(AA->getAnnotation(), true);
llvm::Constant *unit = llvm::ConstantArray::get(M->getModuleIdentifier(),
true);
// Get the two global values corresponding to the ConstantArrays we just
// created to hold the bytes of the strings.
const char *StringPrefix = getContext().Target.getStringSymbolPrefix(true);
new llvm::GlobalVariable(M->getContext(), anno->getType(), false,
llvm::GlobalValue::InternalLinkage, anno,
GV->getName() + StringPrefix, M);
// translation unit name string, emitted into the llvm.metadata section.
llvm::GlobalValue *unitGV =
new llvm::GlobalVariable(M->getContext(), unit->getType(), false,
llvm::GlobalValue::InternalLinkage, unit,
StringPrefix, M);
llvm::Constant *Fields[4] = {
llvm::ConstantExpr::getBitCast(GV, SBP),
llvm::ConstantExpr::getBitCast(annoGV, SBP),
llvm::ConstantExpr::getBitCast(unitGV, SBP),
llvm::ConstantInt::get(llvm::Type::Int32Ty, LineNo)
};
return llvm::ConstantStruct::get(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.
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if (FD->hasAttr<ConstructorAttr>() ||
FD->hasAttr<DestructorAttr>())
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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++.
if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
Linkage == GVA_CXXInline)
return true;
return false;
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Invalid decl");
return VD->getStorageClass() == VarDecl::Static;
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
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const ValueDecl *Global = GD.getDecl();
// 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(Global);
// 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.");
// In C++, if this is marked "extern", defer code generation.
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if (getLangOptions().CPlusPlus && !VD->getInit() &&
(VD->getStorageClass() == VarDecl::Extern ||
VD->isExternC(getContext())))
return;
// In C, if this isn't a definition, defer code generation.
if (!getLangOptions().CPlusPlus && !VD->getInit())
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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)) {
// If the value has already been used, add it directly to the
// DeferredDeclsToEmit list.
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const char *MangledName = getMangledName(GD);
if (GlobalDeclMap.count(MangledName))
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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.
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DeferredDecls[MangledName] = GD;
}
return;
}
// Otherwise emit the definition.
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EmitGlobalDefinition(GD);
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}
void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
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const ValueDecl *D = GD.getDecl();
if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
EmitCXXConstructor(CD, GD.getCtorType());
else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D))
EmitCXXDestructor(DD, GD.getDtorType());
else if (isa<FunctionDecl>(D))
EmitGlobalFunctionDefinition(GD);
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else if (const VarDecl *VD = dyn_cast<VarDecl>(D))
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else {
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(const char *MangledName,
const llvm::Type *Ty,
GlobalDecl D) {
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry) {
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 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.
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llvm::DenseMap<const char*, GlobalDecl>::iterator DDI =
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);
}
// 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;
if (!isa<llvm::FunctionType>(Ty)) {
Ty = llvm::FunctionType::get(llvm::Type::VoidTy,
std::vector<const llvm::Type*>(), false);
IsIncompleteFunction = true;
}
llvm::Function *F = llvm::Function::Create(cast<llvm::FunctionType>(Ty),
llvm::Function::ExternalLinkage,
"", &getModule());
F->setName(MangledName);
if (D.getDecl())
SetFunctionAttributes(cast<FunctionDecl>(D.getDecl()), F,
IsIncompleteFunction);
Entry = F;
return F;
}
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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(GD.getDecl()->getType());
return GetOrCreateLLVMFunction(getMangledName(GD.getDecl()), 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,
const char *Name) {
// Convert Name to be a uniqued string from the IdentifierInfo table.
Name = getContext().Idents.get(Name).getName();
return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl());
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}
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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(const char *MangledName,
const llvm::PointerType*Ty,
const VarDecl *D) {
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
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if (Entry->getType() == Ty)
return Entry;
// Make sure the result is of the correct type.
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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.
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llvm::DenseMap<const char*, 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);
}
new llvm::GlobalVariable(getModule().getContext(),
Ty->getElementType(), false,
0, "", &getModule(),
GV->setName(MangledName);
// 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.
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GV->setConstant(D->getType().isConstant(Context));
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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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if (D->hasAttr<WeakAttr>() ||
D->hasAttr<WeakImportAttr>())
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GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
GV->setThreadLocal(D->isThreadSpecified());
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}
return Entry = GV;
}
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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);
const llvm::PointerType *PTy =
llvm::PointerType::get(Ty, ASTTy.getAddressSpace());
return GetOrCreateLLVMGlobal(getMangledName(D), PTy, D);
}
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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,
const char *Name) {
// Convert Name to be a uniqued string from the IdentifierInfo table.
Name = getContext().Idents.get(Name).getName();
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.
const char *MangledName = getMangledName(D);
if (GlobalDeclMap.count(MangledName) == 0) {
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DeferredDecls[MangledName] = GlobalDecl(D);
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}
}
// The tentative definition is the only definition.
EmitGlobalVarDefinition(D);
}
void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
llvm::Constant *Init = 0;
QualType ASTTy = D->getType();
if (D->getInit() == 0) {
// This is a tentative definition; tentative definitions are
// implicitly initialized with { 0 }.
//
// Note that tentative definitions are only emitted at the end of
// a translation unit, so they should never have incomplete
// type. In addition, EmitTentativeDefinition makes sure that we
// never attempt to emit a tentative definition if a real one
// exists. A use may still exists, however, so we still may need
// to do a RAUW.
assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
Init = llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(ASTTy));
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Init = EmitConstantExpr(D->getInit(), D->getType());
if (!Init) {
ErrorUnsupported(D, "static initializer");
QualType T = D->getInit()->getType();
Init = llvm::UndefValue::get(getTypes().ConvertType(T));
}
llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType);
// Strip off a bitcast if we got one back.
if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
assert(CE->getOpcode() == llvm::Instruction::BitCast);
Entry = CE->getOperand(0);
}
// Entry is now either a Function or GlobalVariable.
llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry);
// We have a definition after a declaration with the wrong type.
// We must make a new GlobalVariable* and update everything that used OldGV
// (a declaration or tentative definition) with the new GlobalVariable*
// (which will be a definition).
//
// This happens if there is a prototype for a global (e.g.
// "extern int x[];") and then a definition of a different type (e.g.
// "int x[10];"). This also happens when an initializer has a different type
// from the type of the global (this happens with unions).
if (GV == 0 ||
GV->getType()->getElementType() != InitType ||
GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) {
// Remove the old entry from GlobalDeclMap so that we'll create a new one.
GlobalDeclMap.erase(getMangledName(D));
// Make a new global with the correct type, this is now guaranteed to work.
GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType));
GV->takeName(cast<llvm::GlobalValue>(Entry));
// Replace all uses of the old global with the new global
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(GV, Entry->getType());
Entry->replaceAllUsesWith(NewPtrForOldDecl);
// Erase the old global, since it is no longer used.
cast<llvm::GlobalValue>(Entry)->eraseFromParent();
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if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) {
SourceManager &SM = Context.getSourceManager();
AddAnnotation(EmitAnnotateAttr(GV, AA,
SM.getInstantiationLineNumber(D->getLocation())));
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GV->setInitializer(Init);
GV->setConstant(D->getType().isConstant(Context));
GV->setAlignment(getContext().getDeclAlignInBytes(D));
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// Set the llvm linkage type as appropriate.
if (D->getStorageClass() == VarDecl::Static)
GV->setLinkage(llvm::Function::InternalLinkage);
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else if (D->hasAttr<DLLImportAttr>())
GV->setLinkage(llvm::Function::DLLImportLinkage);
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else if (D->hasAttr<DLLExportAttr>())
GV->setLinkage(llvm::Function::DLLExportLinkage);
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else if (D->hasAttr<WeakAttr>())
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GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
else if (!CompileOpts.NoCommon &&
(!D->hasExternalStorage() && !D->getInit()))
GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
// Emit global variable debug information.
DI->setLocation(D->getLocation());
DI->EmitGlobalVariable(GV, D);
}
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}
/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
/// implement a function with no prototype, e.g. "int foo() {}". If there are
/// existing call uses of the old function in the module, this adjusts them to
/// call the new function directly.
///
/// This is not just a cleanup: the always_inline pass requires direct calls to
/// functions to be able to inline them. If there is a bitcast in the way, it
/// won't inline them. Instcombine normally deletes these calls, but it isn't
/// run at -O0.
static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
llvm::Function *NewFn) {
// If we're redefining a global as a function, don't transform it.
llvm::Function *OldFn = dyn_cast<llvm::Function>(Old);
if (OldFn == 0) return;
const llvm::Type *NewRetTy = NewFn->getReturnType();
llvm::SmallVector<llvm::Value*, 4> ArgList;
for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end();
UI != E; ) {
// TODO: Do invokes ever occur in C code? If so, we should handle them too.
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unsigned OpNo = UI.getOperandNo();
llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*UI++);
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if (!CI || OpNo != 0) continue;
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// If the return types don't match exactly, and if the call isn't dead, then
// we can't transform this call.
if (CI->getType() != NewRetTy && !CI->use_empty())
continue;
// If the function was passed too few arguments, don't transform. If extra
// arguments were passed, we silently drop them. If any of the types
// mismatch, we don't transform.
unsigned ArgNo = 0;
bool DontTransform = false;
for (llvm::Function::arg_iterator AI = NewFn->arg_begin(),
E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) {
if (CI->getNumOperands()-1 == ArgNo ||
CI->getOperand(ArgNo+1)->getType() != AI->getType()) {
DontTransform = true;
break;
}
}
if (DontTransform)
continue;
// Okay, we can transform this. Create the new call instruction and copy
// over the required information.
ArgList.append(CI->op_begin()+1, CI->op_begin()+1+ArgNo);
llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(),
ArgList.end(), "", CI);
ArgList.clear();
if (NewCall->getType() != llvm::Type::VoidTy)
NewCall->takeName(CI);
NewCall->setCallingConv(CI->getCallingConv());
NewCall->setAttributes(CI->getAttributes());
// Finally, remove the old call, replacing any uses with the new one.
if (!CI->use_empty())
CI->replaceAllUsesWith(NewCall);
CI->eraseFromParent();
}
}
void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) {
const llvm::FunctionType *Ty;
const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl());
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
bool isVariadic = D->getType()->getAsFunctionProtoType()->isVariadic();
Ty = getTypes().GetFunctionType(getTypes().getFunctionInfo(MD), isVariadic);
} else {
Ty = cast<llvm::FunctionType>(getTypes().ConvertType(D->getType()));
// As a special case, make sure that definitions of K&R function
// "type foo()" aren't declared as varargs (which forces the backend
// to do unnecessary work).
if (D->getType()->isFunctionNoProtoType()) {
assert(Ty->isVarArg() && "Didn't lower type as expected");
// Due to stret, the lowered function could have arguments.
// Just create the same type as was lowered by ConvertType
// but strip off the varargs bit.
std::vector<const llvm::Type*> Args(Ty->param_begin(), Ty->param_end());
Ty = llvm::FunctionType::get(Ty->getReturnType(), Args, false);
}
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}
// Get or create the prototype for the function.
llvm::Constant *Entry = GetAddrOfFunction(GD, Ty);
// Strip off a bitcast if we got one back.
if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
assert(CE->getOpcode() == llvm::Instruction::BitCast);
Entry = CE->getOperand(0);
}
if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) {
llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry);
// If the types mismatch then we have to rewrite the definition.
assert(OldFn->isDeclaration() &&
"Shouldn't replace non-declaration");
// F is the Function* for the one with the wrong type, we must make a new