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gerrit-public.fairphone.software / platform / external / clang / e9ee23edd17c4bb7f271e67f8790792b4de677fc / . / lib / CodeGen / CodeGenModule.cpp
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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 "CodeGenFunction.h"
#include "CGCall.h"
#include "CGObjCRuntime.h"
#include "Mangle.h"
#include "TargetInfo.h"
#include "clang/CodeGen/CodeGenOptions.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclCXX.h"
#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"
#include "llvm/CallingConv.h"
#include "llvm/Module.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;
using namespace CodeGen;
CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO,
llvm::Module &M, const llvm::TargetData &TD,
Diagnostic &diags)
: BlockModule(C, M, TD, Types, *this), Context(C),
Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M),
TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags),
Types(C, M, TD, getTargetCodeGenInfo().getABIInfo()),
MangleCtx(C, diags), VTables(*this), Runtime(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 debug info generation is enabled, create the CGDebugInfo object.
DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0;
}
CodeGenModule::~CodeGenModule() {
delete Runtime;
delete DebugInfo;
}
void CodeGenModule::createObjCRuntime() {
if (!Features.NeXTRuntime)
Runtime = CreateGNUObjCRuntime(*this);
else if (Features.ObjCNonFragileABI)
Runtime = CreateMacNonFragileABIObjCRuntime(*this);
else
Runtime = CreateMacObjCRuntime(*this);
}
void CodeGenModule::Release() {
EmitDeferred();
EmitCXXGlobalInitFunc();
EmitCXXGlobalDtorFunc();
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;
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;
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;
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;
}
}
// 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.
if (GV->hasLocalLinkage()) {
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
return;
}
switch (getDeclVisibilityMode(D)) {
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());
if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND))
return getMangledCXXCtorName(Buffer, D, GD.getCtorType());
if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND))
return getMangledCXXDtorName(Buffer, D, GD.getDtorType());
return getMangledName(Buffer, ND);
}
/// \brief Retrieves the mangled name for the given declaration.
///
/// If the given declaration requires a mangled name, returns an
/// const char* containing the mangled name. Otherwise, returns
/// the unmangled name.
///
void CodeGenModule::getMangledName(MangleBuffer &Buffer,
const NamedDecl *ND) {
if (!getMangleContext().shouldMangleDeclName(ND)) {
assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
Buffer.setString(ND->getNameAsCString());
return;
}
getMangleContext().mangleName(ND, Buffer.getBuffer());
}
llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) {
return getModule().getNamedValue(Name);
}
/// 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));
}
/// 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),
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, AT, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(AT, Ctors),
GlobalName);
}
}
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,
"llvm.global.annotations");
gv->setSection("llvm.metadata");
}
static CodeGenModule::GVALinkage
GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
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;
// If this is a virtual method and its class has a key method in another
// translation unit, we know that this method will be present in that
// translation unit. In this translation unit we will use this method
// only for inlining and analysis. This is the semantics of c99 inline.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
const CXXRecordDecl *RD = MD->getParent();
if (MD->isVirtual() &&
CodeGenVTables::isKeyFunctionInAnotherTU(Context, RD))
return CodeGenModule::GVA_C99Inline;
}
return CodeGenModule::GVA_CXXInline;
}
llvm::GlobalValue::LinkageTypes
CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
if (Linkage == GVA_Internal) {
return llvm::Function::InternalLinkage;
} else if (D->hasAttr<DLLExportAttr>()) {
return llvm::Function::DLLExportLinkage;
} 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;
} 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;
} else {
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) {
GV->setLinkage(getFunctionLinkage(D));
SetCommonAttributes(D, GV);
}
void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
const CGFunctionInfo &Info,
llvm::Function *F) {
unsigned CallingConv;
AttributeListType AttributeList;
ConstructAttributeList(Info, D, AttributeList, CallingConv);
F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
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);
if (D->hasAttr<AlwaysInlineAttr>())
F->addFnAttr(llvm::Attribute::AlwaysInline);
if (D->hasAttr<NoInlineAttr>())
F->addFnAttr(llvm::Attribute::NoInline);
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);
if (D->hasAttr<UsedAttr>())
AddUsedGlobal(GV);
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);
}
void CodeGenModule::SetFunctionAttributes(GlobalDecl GD,
llvm::Function *F,
bool IsIncompleteFunction) {
const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
if (!IsIncompleteFunction)
SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F);
// Only a few attributes are set on declarations; these may later be
// overridden by a definition.
if (FD->hasAttr<DLLImportAttr>()) {
F->setLinkage(llvm::Function::DLLImportLinkage);
} 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);
}
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.");
LLVMUsed.push_back(GV);
}
void CodeGenModule::EmitLLVMUsed() {
// Don't create llvm.used if there is no need.
if (LLVMUsed.empty())
return;
const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
// 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 (UsedArray.empty())
return;
llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size());
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(getModule(), ATy, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(ATy, UsedArray),
"llvm.used");
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;
}
GlobalDecl D = DeferredDeclsToEmit.back();
DeferredDeclsToEmit.pop_back();
// 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.
MangleBuffer Name;
getMangledName(Name, D);
llvm::GlobalValue *CGRef = GetGlobalValue(Name);
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::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.
llvm::GlobalValue *annoGV =
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 =
new llvm::GlobalVariable(*M, unit->getType(), false,
llvm::GlobalValue::PrivateLinkage, unit,
".str");
// Create the ConstantStruct for the global annotation.
llvm::Constant *Fields[4] = {
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.
if (Features.EmitAllDecls || Global->hasAttr<UsedAttr>())
return false;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
// Constructors and destructors should never be deferred.
if (FD->hasAttr<ConstructorAttr>() ||
FD->hasAttr<DestructorAttr>())
return false;
// 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())
return false;
}
}
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");
// 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;
}
return false;
}
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());
else
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.
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)
return;
}
// 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);
return;
}
// 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;
}
}
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 (isa<CXXMethodDecl>(D))
getVTables().EmitVTableRelatedData(GD);
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()");
}
/// 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>())
Entry->setLinkage(llvm::Function::ExternalLinkage);
WeakRefReferences.erase(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 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::getVoidTy(VMContext),
std::vector<const llvm::Type*>(), false);
IsIncompleteFunction = true;
}
llvm::Function *F = llvm::Function::Create(cast<llvm::FunctionType>(Ty),
llvm::Function::ExternalLinkage,
MangledName, &getModule());
assert(F->getName() == MangledName && "name was uniqued!");
if (D.getDecl())
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())) {
// 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)) {
if (CD->isImplicit()) {
assert(CD->isUsed() && "Sema doesn't consider constructor as used.");
DeferredDeclsToEmit.push_back(D);
}
} else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) {
if (DD->isImplicit()) {
assert(DD->isUsed() && "Sema doesn't consider destructor as used.");
DeferredDeclsToEmit.push_back(D);
}
} else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
if (MD->isCopyAssignment() && MD->isImplicit()) {
assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used.");
DeferredDeclsToEmit.push_back(D);
}
}
}
return F;
}
/// 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,
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);
}
/// 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());
}
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;
}
/// 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 (Entry) {
if (WeakRefReferences.count(Entry)) {
if (D && !D->hasAttr<WeakAttr>())
Entry->setLinkage(llvm::Function::ExternalLinkage);
WeakRefReferences.erase(Entry);
}
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,
llvm::GlobalValue::ExternalLinkage,
0, MangledName, 0,
false, Ty->getAddressSpace());
// Handle things which are present even on external declarations.
if (D) {
// FIXME: This code is overly simple and should be merged with other global
// handling.
GV->setConstant(DeclIsConstantGlobal(Context, D));
// FIXME: Merge with other attribute handling code.
if (D->getStorageClass() == VarDecl::PrivateExtern)
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
if (D->hasAttr<WeakAttr>() ||
D->hasAttr<WeakImportAttr>())
GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
GV->setThreadLocal(D->isThreadSpecified());
}
return GV;
}
/// 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());
MangleBuffer MangledName;
getMangledName(MangledName, D);
return GetOrCreateLLVMGlobal(MangledName, PTy, D);
}
/// 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!");
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;
return;
}
}
// The tentative definition is the only definition.
EmitGlobalVarDefinition(D);
}
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.
const FunctionDecl *Def = 0;
if (KeyFunction->getBody(Def))
KeyFunction = cast<CXXMethodDecl>(Def);
switch (KeyFunction->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
if (KeyFunction->isInlined())
return llvm::GlobalVariable::WeakODRLinkage;
return llvm::GlobalVariable::ExternalLinkage;
case TSK_ImplicitInstantiation:
case TSK_ExplicitInstantiationDefinition:
return llvm::GlobalVariable::WeakODRLinkage;
case TSK_ExplicitInstantiationDeclaration:
// FIXME: Use available_externally linkage. However, this currently
// breaks LLVM's build due to undefined symbols.
// return llvm::GlobalVariable::AvailableExternallyLinkage;
return llvm::GlobalVariable::WeakODRLinkage;
}
}
switch (RD->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
case TSK_ImplicitInstantiation:
case TSK_ExplicitInstantiationDefinition:
return llvm::GlobalVariable::WeakODRLinkage;
case TSK_ExplicitInstantiationDeclaration:
// FIXME: Use available_externally linkage. However, this currently
// breaks LLVM's build due to undefined symbols.
// return llvm::GlobalVariable::AvailableExternallyLinkage;
return llvm::GlobalVariable::WeakODRLinkage;
}
// Silence GCC warning.
return llvm::GlobalVariable::WeakODRLinkage;
}
static CodeGenModule::GVALinkage
GetLinkageForVariable(ASTContext &Context, const VarDecl *VD) {
// If this is a static data member, compute the kind of template
// specialization. Otherwise, this variable is not part of a
// template.
TemplateSpecializationKind TSK = TSK_Undeclared;
if (VD->isStaticDataMember())
TSK = VD->getTemplateSpecializationKind();
Linkage L = VD->getLinkage();
if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
VD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return CodeGenModule::GVA_Internal;
case ExternalLinkage:
switch (TSK) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
return CodeGenModule::GVA_StrongExternal;
case TSK_ExplicitInstantiationDeclaration:
llvm_unreachable("Variable should not be instantiated");
// Fall through to treat this like any other instantiation.
case TSK_ExplicitInstantiationDefinition:
return CodeGenModule::GVA_ExplicitTemplateInstantiation;
case TSK_ImplicitInstantiation:
return CodeGenModule::GVA_TemplateInstantiation;
}
}
return CodeGenModule::GVA_StrongExternal;
}
CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const {
return CharUnits::fromQuantity(
TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth());
}
void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
llvm::Constant *Init = 0;
QualType ASTTy = D->getType();
bool NonConstInit = false;
const Expr *InitExpr = D->getAnyInitializer();
if (!InitExpr) {
// 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 = EmitNullConstant(D->getType());
} else {
Init = EmitConstantExpr(InitExpr, D->getType());
if (!Init) {
QualType T = InitExpr->getType();
if (getLangOptions().CPlusPlus) {
EmitCXXGlobalVarDeclInitFunc(D);
Init = EmitNullConstant(T);
NonConstInit = true;
} else {
ErrorUnsupported(D, "static initializer");
Init = llvm::UndefValue::get(getTypes().ConvertType(T));
}
}
}
const llvm::Type* InitType = Init->getType();
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 ||
// all zero index gep.
CE->getOpcode() == llvm::Instruction::GetElementPtr);
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()) {
// Move the old entry aside so that we'll create a new one.
Entry->setName(llvm::StringRef());
// Make a new global with the correct type, this is now guaranteed to work.
GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType));
// 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();
}
if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) {
SourceManager &SM = Context.getSourceManager();
AddAnnotation(EmitAnnotateAttr(GV, AA,
SM.getInstantiationLineNumber(D->getLocation())));
}
GV->setInitializer(Init);
// If it is safe to mark the global 'constant', do so now.
GV->setConstant(false);
if (!NonConstInit && DeclIsConstantGlobal(Context, D))
GV->setConstant(true);
GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
// Set the llvm linkage type as appropriate.
GVALinkage Linkage = GetLinkageForVariable(getContext(), D);
if (Linkage == GVA_Internal)
GV->setLinkage(llvm::Function::InternalLinkage);
else if (D->hasAttr<DLLImportAttr>())
GV->setLinkage(llvm::Function::DLLImportLinkage);
else if (D->hasAttr<DLLExportAttr>())
GV->setLinkage(llvm::Function::DLLExportLinkage);
else if (D->hasAttr<WeakAttr>()) {
if (GV->isConstant())
GV->setLinkage(llvm::GlobalVariable::WeakODRLinkage);
else
GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
} else if (Linkage == GVA_TemplateInstantiation ||
Linkage == GVA_ExplicitTemplateInstantiation)
// FIXME: It seems like we can provide more specific linkage here
// (LinkOnceODR, WeakODR).
GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon &&
!D->hasExternalStorage() && !D->getInit() &&
!D->getAttr<SectionAttr>()) {
GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
// common vars aren't constant even if declared const.
GV->setConstant(false);
} else
GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
SetCommonAttributes(D, GV);
// Emit global variable debug information.
if (CGDebugInfo *DI = getDebugInfo()) {
DI->setLocation(D->getLocation());
DI->EmitGlobalVariable(GV, D);
}
}
/// 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.
llvm::Value::use_iterator I = UI++; // Increment before the CI is erased.
llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I);
llvm::CallSite CS(CI);
if (!CI || !CS.isCallee(I)) continue;
// 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 (CS.arg_size() == ArgNo ||
CS.getArgument(ArgNo)->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(CS.arg_begin(), CS.arg_begin() + ArgNo);
llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(),
ArgList.end(), "", CI);
ArgList.clear();
if (!NewCall->getType()->isVoidTy())
NewCall->takeName(CI);
NewCall->setAttributes(CI->getAttributes());
NewCall->setCallingConv(CI->getCallingConv());
// Finally, remove the old call, replacing any uses with the new one.
if (!CI->use_empty())
CI->replaceAllUsesWith(NewCall);
// Copy debug location attached to CI.
if (!CI->getDebugLoc().isUnknown())
NewCall->setDebugLoc(CI->getDebugLoc());
CI->eraseFromParent();
}
}
void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) {
const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl());
const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD);
getMangleContext().mangleInitDiscriminator();
// 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
// Function* and update everything that used F (a declaration) with the new
// Function* (which will be a definition).
//
// This happens if there is a prototype for a function
// (e.g. "int f()") and then a definition of a different type
// (e.g. "int f(int x)"). Move the old function aside so that it
// doesn't interfere with GetAddrOfFunction.
OldFn->setName(llvm::StringRef());
llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty));
// If this is an implementation of a function without a prototype, try to
// replace any existing uses of the function (which may be calls) with uses
// of the new function
if (D->getType()->isFunctionNoProtoType()) {
ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn);
OldFn->removeDeadConstantUsers();
}
// Replace uses of F with the Function we will endow with a body.
if (!Entry->use_empty()) {
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(NewFn, Entry->getType());
Entry->replaceAllUsesWith(NewPtrForOldDecl);
}
// Ok, delete the old function now, which is dead.
OldFn->eraseFromParent();
Entry = NewFn;
}
llvm::Function *Fn = cast<llvm::Function>(Entry);
CodeGenFunction(*this).GenerateCode(D, Fn);
SetFunctionDefinitionAttributes(D, Fn);
SetLLVMFunctionAttributesForDefinition(D, Fn);
if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
AddGlobalCtor(Fn, CA->getPriority());
if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
AddGlobalDtor(Fn, DA->getPriority());
}
void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
const AliasAttr *AA = D->getAttr<AliasAttr>();
assert(AA && "Not an alias?");
MangleBuffer MangledName;
getMangledName(MangledName, GD);
// If there is a definition in the module, then it wins over the alias.
// This is dubious, but allow it to be safe. Just ignore the alias.
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
if (Entry && !Entry->isDeclaration())
return;
const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
// Create a reference to the named value. This ensures that it is emitted
// if a deferred decl.
llvm::Constant *Aliasee;
if (isa<llvm::FunctionType>(DeclTy))
Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl());
else
Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
llvm::PointerType::getUnqual(DeclTy), 0);
// Create the new alias itself, but don't set a name yet.
llvm::GlobalValue *GA =
new llvm::GlobalAlias(Aliasee->getType(),
llvm::Function::ExternalLinkage,
"", Aliasee, &getModule());
if (Entry) {
assert(Entry->isDeclaration());
// If there is a declaration in the module, then we had an extern followed
// by the alias, as in:
// extern int test6();
// ...
// int test6() __attribute__((alias("test7")));
//
// Remove it and replace uses of it with the alias.
GA->takeName(Entry);
Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA,
Entry->getType()));
Entry->eraseFromParent();
} else {
GA->setName(MangledName.getString());
}
// Set attributes which are particular to an alias; this is a
// specialization of the attributes which may be set on a global
// variable/function.
if (D->hasAttr<DLLExportAttr>()) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// The dllexport attribute is ignored for undefined symbols.
if (FD->getBody())
GA->setLinkage(llvm::Function::DLLExportLinkage);
} else {
GA->setLinkage(llvm::Function::DLLExportLinkage);
}
} else if (D->hasAttr<WeakAttr>() ||
D->hasAttr<WeakRefAttr>() ||
D->hasAttr<WeakImportAttr>()) {
GA->setLinkage(llvm::Function::WeakAnyLinkage);
}
SetCommonAttributes(D, GA);
}
/// getBuiltinLibFunction - Given a builtin id for a function like
/// "__builtin_fabsf", return a Function* for "fabsf".
llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD,
unsigned BuiltinID) {
assert((Context.BuiltinInfo.isLibFunction(BuiltinID) ||
Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) &&
"isn't a lib fn");
// Get the name, skip over the __builtin_ prefix (if necessary).
const char *Name = Context.BuiltinInfo.GetName(BuiltinID);
if (Context.BuiltinInfo.isLibFunction(BuiltinID))
Name += 10;
const llvm::FunctionType *Ty =
cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType()));
return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD));
}
llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys,
unsigned NumTys) {
return llvm::Intrinsic::getDeclaration(&getModule(),
(llvm::Intrinsic::ID)IID, Tys, NumTys);
}
llvm::Function *CodeGenModule::getMemCpyFn(const llvm::Type *DestType,
const llvm::Type *SrcType,
const llvm::Type *SizeType) {
const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType };
return getIntrinsic(llvm::Intrinsic::memcpy, ArgTypes, 3);
}
llvm::Function *CodeGenModule::getMemMoveFn(const llvm::Type *DestType,
const llvm::Type *SrcType,
const llvm::Type *SizeType) {
const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType };
return getIntrinsic(llvm::Intrinsic::memmove, ArgTypes, 3);
}
llvm::Function *CodeGenModule::getMemSetFn(const llvm::Type *DestType,
const llvm::Type *SizeType) {
const llvm::Type *ArgTypes[2] = { DestType, SizeType };
return getIntrinsic(llvm::Intrinsic::memset, ArgTypes, 2);
}
static llvm::StringMapEntry<llvm::Constant*> &
GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map,
const StringLiteral *Literal,
bool TargetIsLSB,
bool &IsUTF16,
unsigned &StringLength) {
unsigned NumBytes = Literal->getByteLength();
// Check for simple case.
if (!Literal->containsNonAsciiOrNull()) {
StringLength = NumBytes;
return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(),
StringLength));
}
// Otherwise, convert the UTF8 literals into a byte string.
llvm::SmallVector<UTF16, 128> ToBuf(NumBytes);
const UTF8 *FromPtr = (UTF8 *)Literal->getStrData();
UTF16 *ToPtr = &ToBuf[0];
ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
&ToPtr, ToPtr + NumBytes,
strictConversion);
// Check for conversion failure.
if (Result != conversionOK) {
// FIXME: Have Sema::CheckObjCString() validate the UTF-8 string and remove
// this duplicate code.
assert(Result == sourceIllegal && "UTF-8 to UTF-16 conversion failed");
StringLength = NumBytes;
return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(),
StringLength));
}
// ConvertUTF8toUTF16 returns the length in ToPtr.
StringLength = ToPtr - &ToBuf[0];
// Render the UTF-16 string into a byte array and convert to the target byte
// order.
//
// FIXME: This isn't something we should need to do here.
llvm::SmallString<128> AsBytes;
AsBytes.reserve(StringLength * 2);
for (unsigned i = 0; i != StringLength; ++i) {
unsigned short Val = ToBuf[i];
if (TargetIsLSB) {
AsBytes.push_back(Val & 0xFF);
AsBytes.push_back(Val >> 8);
} else {
AsBytes.push_back(Val >> 8);
AsBytes.push_back(Val & 0xFF);
}
}
// Append one extra null character, the second is automatically added by our
// caller.
AsBytes.push_back(0);
IsUTF16 = true;
return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size()));
}
llvm::Constant *
CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
unsigned StringLength = 0;
bool isUTF16 = false;
llvm::StringMapEntry<llvm::Constant*> &Entry =
GetConstantCFStringEntry(CFConstantStringMap, Literal,
getTargetData().isLittleEndian(),
isUTF16, StringLength);
if (llvm::Constant *C = Entry.getValue())
return C;
llvm::Constant *Zero =
llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext));
llvm::Constant *Zeros[] = { Zero, Zero };
// If we don't already have it, get __CFConstantStringClassReference.
if (!CFConstantStringClassRef) {
const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
Ty = llvm::ArrayType::get(Ty, 0);
llvm::Constant *GV = CreateRuntimeVariable(Ty,
"__CFConstantStringClassReference");
// Decay array -> ptr
CFConstantStringClassRef =
llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
}
QualType CFTy = getContext().getCFConstantStringType();
const llvm::StructType *STy =
cast<llvm::StructType>(getTypes().ConvertType(CFTy));
std::vector<llvm::Constant*> Fields(4);
// Class pointer.
Fields[0] = CFConstantStringClassRef;
// Flags.
const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy);
Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) :
llvm::ConstantInt::get(Ty, 0x07C8);
// String pointer.
llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str());
llvm::GlobalValue::LinkageTypes Linkage;
bool isConstant;
if (isUTF16) {
// FIXME: why do utf strings get "_" labels instead of "L" labels?
Linkage = llvm::GlobalValue::InternalLinkage;
// Note: -fwritable-strings doesn't make unicode CFStrings writable, but
// does make plain ascii ones writable.
isConstant = true;
} else {
Linkage = llvm::GlobalValue::PrivateLinkage;
isConstant = !Features.WritableStrings;
}
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C,
".str");
if (isUTF16) {
CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy);
GV->setAlignment(Align.getQuantity());
}
Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
// String length.
Ty = getTypes().ConvertType(getContext().LongTy);
Fields[3] = llvm::ConstantInt::get(Ty, StringLength);
// The struct.
C = llvm::ConstantStruct::get(STy, Fields);
GV = new llvm::GlobalVariable(getModule(), C->getType(), true,
llvm::GlobalVariable::PrivateLinkage, C,
"_unnamed_cfstring_");
if (const char *Sect = getContext().Target.getCFStringSection())
GV->setSection(Sect);
Entry.setValue(GV);
return GV;
}
/// GetStringForStringLiteral - Return the appropriate bytes for a
/// string literal, properly padded to match the literal type.
std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) {
const char *StrData = E->getStrData();
unsigned Len = E->getByteLength();
const ConstantArrayType *CAT =
getContext().getAsConstantArrayType(E->getType());
assert(CAT && "String isn't pointer or array!");
// Resize the string to the right size.
std::string Str(StrData, StrData+Len);
uint64_t RealLen = CAT->getSize().getZExtValue();
if (E->isWide())
RealLen *= getContext().Target.getWCharWidth()/8;
Str.resize(RealLen, '\0');
return Str;
}
/// GetAddrOfConstantStringFromLiteral - Return a pointer to a
/// constant array for the given string literal.
llvm::Constant *
CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
// FIXME: This can be more efficient.
// FIXME: We shouldn't need to bitcast the constant in the wide string case.
llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S));
if (S->isWide()) {
llvm::Type *DestTy =
llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType()));
C = llvm::ConstantExpr::getBitCast(C, DestTy);
}
return C;
}
/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
/// array for the given ObjCEncodeExpr node.
llvm::Constant *
CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
std::string Str;
getContext().getObjCEncodingForType(E->getEncodedType(), Str);
return GetAddrOfConstantCString(Str);
}
/// GenerateWritableString -- Creates storage for a string literal.
static llvm::Constant *GenerateStringLiteral(const std::string &str,
bool constant,
CodeGenModule &CGM,
const char *GlobalName) {
// Create Constant for this string literal. Don't add a '\0'.
llvm::Constant *C =
llvm::ConstantArray::get(CGM.getLLVMContext(), str, false);
// Create a global variable for this string
return new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant,
llvm::GlobalValue::PrivateLinkage,
C, GlobalName);
}
/// GetAddrOfConstantString - Returns a pointer to a character array
/// containing the literal. This contents are exactly that of the
/// given string, i.e. it will not be null terminated automatically;
/// see GetAddrOfConstantCString. Note that whether the result is
/// actually a pointer to an LLVM constant depends on
/// Feature.WriteableStrings.
///
/// The result has pointer to array type.
llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str,
const char *GlobalName) {
bool IsConstant = !Features.WritableStrings;
// Get the default prefix if a name wasn't specified.
if (!GlobalName)
GlobalName = ".str";
// Don't share any string literals if strings aren't constant.
if (!IsConstant)
return GenerateStringLiteral(str, false, *this, GlobalName);
llvm::StringMapEntry<llvm::Constant *> &Entry =
ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
if (Entry.getValue())
return Entry.getValue();
// Create a global variable for this.
llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName);
Entry.setValue(C);
return C;
}
/// GetAddrOfConstantCString - Returns a pointer to a character
/// array containing the literal and a terminating '\-'
/// character. The result has pointer to array type.
llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str,
const char *GlobalName){
return GetAddrOfConstantString(str + '\0', GlobalName);
}
/// EmitObjCPropertyImplementations - Emit information for synthesized
/// properties for an implementation.
void CodeGenModule::EmitObjCPropertyImplementations(const
ObjCImplementationDecl *D) {
for (ObjCImplementationDecl::propimpl_iterator
i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) {
ObjCPropertyImplDecl *PID = *i;
// Dynamic is just for type-checking.
if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
ObjCPropertyDecl *PD = PID->getPropertyDecl();
// Determine which methods need to be implemented, some may have
// been overridden. Note that ::isSynthesized is not the method
// we want, that just indicates if the decl came from a
// property. What we want to know is if the method is defined in
// this implementation.
if (!D->getInstanceMethod(PD->getGetterName()))
CodeGenFunction(*this).GenerateObjCGetter(
const_cast<ObjCImplementationDecl *>(D), PID);
if (!PD->isReadOnly() &&
!D->getInstanceMethod(PD->getSetterName()))
CodeGenFunction(*this).GenerateObjCSetter(
const_cast<ObjCImplementationDecl *>(D), PID);
}
}
}
/// EmitNamespace - Emit all declarations in a namespace.
void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) {
for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end();
I != E; ++I)
EmitTopLevelDecl(*I);
}
// EmitLinkageSpec - Emit all declarations in a linkage spec.
void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
if (LSD->getLanguage() != LinkageSpecDecl::lang_c &&
LSD->getLanguage() != LinkageSpecDecl::lang_cxx) {
ErrorUnsupported(LSD, "linkage spec");
return;
}
for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end();
I != E; ++I)
EmitTopLevelDecl(*I);
}
/// EmitTopLevelDecl - Emit code for a single top level declaration.
void CodeGenModule::EmitTopLevelDecl(Decl *D) {
// If an error has occurred, stop code generation, but continue
// parsing and semantic analysis (to ensure all warnings and errors
// are emitted).
if (Diags.hasErrorOccurred())
return;
// Ignore dependent declarations.
if (D->getDeclContext() && D->getDeclContext()->isDependentContext())
return;
switch (D->getKind()) {
case Decl::CXXConversion:
case Decl::CXXMethod:
case Decl::Function:
// Skip function templates
if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate())
return;
EmitGlobal(cast<FunctionDecl>(D));
break;
case Decl::Var:
EmitGlobal(cast<VarDecl>(D));
break;
// C++ Decls
case Decl::Namespace:
EmitNamespace(cast<NamespaceDecl>(D));
break;
// No code generation needed.
case Decl::UsingShadow:
case Decl::Using:
case Decl::UsingDirective:
case Decl::ClassTemplate:
case Decl::FunctionTemplate:
case Decl::NamespaceAlias:
break;
case Decl::CXXConstructor:
// Skip function templates
if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate())
return;
EmitCXXConstructors(cast<CXXConstructorDecl>(D));
break;
case Decl::CXXDestructor:
EmitCXXDestructors(cast<CXXDestructorDecl>(D));
break;
case Decl::StaticAssert:
// Nothing to do.
break;
// Objective-C Decls
// Forward declarations, no (immediate) code generation.
case Decl::ObjCClass:
case Decl::ObjCForwardProtocol:
case Decl::ObjCCategory:
case Decl::ObjCInterface:
break;
case Decl::ObjCProtocol:
Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D));
break;
case Decl::ObjCCategoryImpl:
// Categories have properties but don't support synthesize so we
// can ignore them here.
Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
break;
case Decl::ObjCImplementation: {
ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D);
EmitObjCPropertyImplementations(OMD);
Runtime->GenerateClass(OMD);
break;
}
case Decl::ObjCMethod: {
ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D);
// If this is not a prototype, emit the body.
if (OMD->getBody())
CodeGenFunction(*this).GenerateObjCMethod(OMD);
break;
}
case Decl::ObjCCompatibleAlias:
// compatibility-alias is a directive and has no code gen.
break;
case Decl::LinkageSpec:
EmitLinkageSpec(cast<LinkageSpecDecl>(D));
break;
case Decl::FileScopeAsm: {
FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D);
llvm::StringRef AsmString = AD->getAsmString()->getString();
const std::string &S = getModule().getModuleInlineAsm();
if (S.empty())
getModule().setModuleInlineAsm(AsmString);
else
getModule().setModuleInlineAsm(S + '\n' + AsmString.str());
break;
}
default:
// Make sure we handled everything we should, every other kind is a
// non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind
// function. Need to recode Decl::Kind to do that easily.
assert(isa<TypeDecl>(D) && "Unsupported decl kind");
}
}