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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/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;
/// setGlobalVisibility - Set the visibility for the given LLVM
/// GlobalValue according to the given clang AST visibility value.
static void setGlobalVisibility(llvm::GlobalValue *GV,
VisibilityAttr::VisibilityTypes Vis) {
// Internal definitions should always have default visibility.
if (GV->hasInternalLinkage()) {
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
switch (Vis) {
default: assert(0 && "Unknown visibility!");
case VisibilityAttr::DefaultVisibility:
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
break;
case VisibilityAttr::HiddenVisibility:
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
break;
case VisibilityAttr::ProtectedVisibility:
GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
break;
}
}
static void setGlobalOptionVisibility(llvm::GlobalValue *GV,
LangOptions::VisibilityMode Vis) {
// Internal definitions should always have default visibility.
if (GV->hasInternalLinkage()) {
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
switch (Vis) {
default: assert(0 && "Unknown visibility!");
case LangOptions::NonVisibility:
break;
case LangOptions::DefaultVisibility:
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
break;
case LangOptions::HiddenVisibility:
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
break;
case LangOptions::ProtectedVisibility:
GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
break;
}
}
/// \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 MangledNames.GetOrCreateValue(Name.begin(), Name.end()).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(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(Array->getType(), false,
llvm::GlobalValue::AppendingLinkage, Array,
"llvm.global.annotations", &TheModule);
gv->setSection("llvm.metadata");
}
void CodeGenModule::SetGlobalValueAttributes(const Decl *D,
bool IsInternal,
bool IsInline,
llvm::GlobalValue *GV,
bool ForDefinition) {
// FIXME: Set up linkage and many other things. Note, this is a simple
// approximation of what we really want.
if (!ForDefinition) {
// Only a few attributes are set on declarations.
if (D->hasAttr<DLLImportAttr>()) {
// The dllimport attribute is overridden by a subsequent declaration as
// dllexport.
if (!D->hasAttr<DLLExportAttr>()) {
// dllimport attribute can be applied only to function decls, not to
// definitions.
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
if (!FD->getBody())
GV->setLinkage(llvm::Function::DLLImportLinkage);
} else
GV->setLinkage(llvm::Function::DLLImportLinkage);
} else if (D->hasAttr<WeakAttr>() ||
D->hasAttr<WeakImportAttr>()) {
// "extern_weak" is overloaded in LLVM; we probably should have
// separate linkage types for this.
GV->setLinkage(llvm::Function::ExternalWeakLinkage);
} else {
if (IsInternal) {
GV->setLinkage(llvm::Function::InternalLinkage);
} else {
if (D->hasAttr<DLLExportAttr>()) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// The dllexport attribute is ignored for undefined symbols.
if (FD->getBody())
GV->setLinkage(llvm::Function::DLLExportLinkage);
} else
GV->setLinkage(llvm::Function::DLLExportLinkage);
} else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>() ||
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GV->setLinkage(llvm::Function::WeakAnyLinkage);
// FIXME: Figure out the relative priority of the attribute,
// -fvisibility, and private_extern.
if (ForDefinition) {
if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
setGlobalVisibility(GV, attr->getVisibility());
else
setGlobalOptionVisibility(GV, getLangOptions().getVisibilityMode());
}
if (const SectionAttr *SA = D->getAttr<SectionAttr>())
GV->setSection(SA->getName());
// Only add to llvm.used when we see a definition, otherwise we
// might add multiple times or risk the value being replaced by a
// subsequent RAUW.
if (ForDefinition) {
if (D->hasAttr<UsedAttr>())
void CodeGenModule::SetFunctionAttributes(const Decl *D,
const CGFunctionInfo &Info,
F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
AttributeList.size()));
// Set the appropriate calling convention for the Function.
if (D->hasAttr<FastCallAttr>())
F->setCallingConv(llvm::CallingConv::X86_FastCall);
if (D->hasAttr<StdCallAttr>())
F->setCallingConv(llvm::CallingConv::X86_StdCall);
}
/// SetFunctionAttributesForDefinition - Set function attributes
/// specific to a function definition.
void CodeGenModule::SetFunctionAttributesForDefinition(const Decl *D,
llvm::Function *F) {
if (isa<ObjCMethodDecl>(D)) {
SetGlobalValueAttributes(D, true, false, F, true);
} else {
const FunctionDecl *FD = cast<FunctionDecl>(D);
SetGlobalValueAttributes(FD, FD->getStorageClass() == FunctionDecl::Static,
FD->isInline(), F, true);
}
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);
}
void CodeGenModule::SetMethodAttributes(const ObjCMethodDecl *MD,
llvm::Function *F) {
SetFunctionAttributes(MD, getTypes().getFunctionInfo(MD), F);
SetFunctionAttributesForDefinition(MD, F);
}
void CodeGenModule::SetFunctionAttributes(const FunctionDecl *FD,
llvm::Function *F) {
SetFunctionAttributes(FD, getTypes().getFunctionInfo(FD), F);
SetGlobalValueAttributes(FD, FD->getStorageClass() == FunctionDecl::Static,
FD->isInline(), F, false);
}
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.
if (LLVMUsed.empty())
return;
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llvm::Type *i8PTy = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, LLVMUsed.size());
// 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);
}
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(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()) {
const ValueDecl *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);
llvm::GlobalValue *annoGV =
new llvm::GlobalVariable(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(unit->getType(), false,
llvm::GlobalValue::InternalLinkage, unit,
StringPrefix, M);
// Create the ConstantStruct that is the global annotion.
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.
if (Features.EmitAllDecls || Global->hasAttr<UsedAttr>())
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
// Constructors and destructors should never be deferred.
if (FD->hasAttr<ConstructorAttr>() || FD->hasAttr<DestructorAttr>())
// FIXME: What about inline, and/or extern inline?
if (FD->getStorageClass() != FunctionDecl::Static)
return false;
} else {
const VarDecl *VD = cast<VarDecl>(Global);
if (VD->getStorageClass() != VarDecl::Static)
return false;
}
return true;
}
void CodeGenModule::EmitGlobal(const ValueDecl *Global) {
// If this is an alias definition (which otherwise looks like a declaration)
// emit it now.
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.");
// Forward declarations are emitted lazily on first use.
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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.
const char *MangledName = getMangledName(Global);
if (GlobalDeclMap.count(MangledName))
DeferredDeclsToEmit.push_back(Global);
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] = Global;
}
return;
}
// Otherwise emit the definition.
EmitGlobalDefinition(Global);
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}
void CodeGenModule::EmitGlobalDefinition(const ValueDecl *D) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
EmitGlobalFunctionDefinition(FD);
} else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
EmitGlobalVarDefinition(VD);
} 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,
const FunctionDecl *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.
llvm::DenseMap<const char*, const ValueDecl*>::iterator DDI =
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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);
}
// 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 ShouldSetAttributes = true;
if (!isa<llvm::FunctionType>(Ty)) {
Ty = llvm::FunctionType::get(llvm::Type::VoidTy,
std::vector<const llvm::Type*>(), false);
ShouldSetAttributes = false;
}
llvm::Function *F = llvm::Function::Create(cast<llvm::FunctionType>(Ty),
llvm::Function::ExternalLinkage,
"", &getModule());
F->setName(MangledName);
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if (D && ShouldSetAttributes)
SetFunctionAttributes(D, F);
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(const FunctionDecl *D,
const llvm::Type *Ty) {
// If there was no specific requested type, just convert it now.
if (!Ty)
Ty = getTypes().ConvertType(D->getType());
return GetOrCreateLLVMFunction(getMangledName(D), Ty, D);
}
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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, 0);
}
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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);
// We don't support __thread yet.
if (D && D->isThreadSpecified())
ErrorUnsupported(D, "thread local ('__thread') variable", true);
// 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::DenseMap<const char*, const ValueDecl*>::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);
}
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new llvm::GlobalVariable(Ty->getElementType(), false,
0, "", &getModule(),
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0, Ty->getAddressSpace());
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.
GV->setConstant(D->getType().isConstant(Context));
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// FIXME: Merge with other attribute handling code.
if (D->getStorageClass() == VarDecl::PrivateExtern)
setGlobalVisibility(GV, VisibilityAttr::HiddenVisibility);
if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>())
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GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
}
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::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 }
const llvm::Type *InitTy = getTypes().ConvertTypeForMem(ASTTy);
if (ASTTy->isIncompleteArrayType()) {
// An incomplete array is normally [ TYPE x 0 ], but we need
// to fix it to [ TYPE x 1 ].
const llvm::ArrayType* ATy = cast<llvm::ArrayType>(InitTy);
InitTy = llvm::ArrayType::get(ATy->getElementType(), 1);
}
Init = llvm::Constant::getNullValue(InitTy);
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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);
// If we already have this global and it has an initializer, then
// we are in the rare situation where we emitted the defining
// declaration of the global and are now being asked to emit a
// definition which would be common. This occurs, for example, in
// the following situation because statics can be emitted out of
// order:
//
// static int x;
// static int *y = &x;
// static int x = 10;
// int **z = &y;
//
// Bail here so we don't blow away the definition. Note that if we
// can't distinguish here if we emitted a definition with a null
// initializer, but this case is safe.
if (GV && GV->hasInitializer() && !GV->getInitializer()->isNullValue()) {
assert(!D->getInit() && "Emitting multiple definitions of a decl!");
return;
}
// 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).
//
// FIXME: This also ends up happening if there's a definition followed by
// a tentative definition! (Although Sema rejects that construct
// at the moment.)
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();
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);
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>() || D->hasAttr<WeakImportAttr>())
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GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
else {
// FIXME: This isn't right. This should handle common linkage and other
// stuff.
switch (D->getStorageClass()) {
case VarDecl::Static: assert(0 && "This case handled above");
case VarDecl::Auto:
case VarDecl::Register:
assert(0 && "Can't have auto or register globals");
case VarDecl::None:
if (!D->getInit() && !CompileOpts.NoCommon)
GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
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else
GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
break;
case VarDecl::Extern:
// FIXME: common
break;
case VarDecl::PrivateExtern:
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
// FIXME: common
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}
if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
setGlobalVisibility(GV, attr->getVisibility());
else
setGlobalOptionVisibility(GV, getLangOptions().getVisibilityMode());
if (const SectionAttr *SA = D->getAttr<SectionAttr>())
GV->setSection(SA->getName());
if (D->hasAttr<UsedAttr>())
// Emit global variable debug information.
DI->setLocation(D->getLocation());
DI->EmitGlobalVariable(GV, D);
}
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}
void CodeGenModule::EmitGlobalFunctionDefinition(const FunctionDecl *D) {
const llvm::FunctionType *Ty;
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 teh function.
llvm::Constant *Entry = GetAddrOfFunction(D, 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) {
// If the types mismatch then we have to rewrite the definition.
assert(cast<llvm::GlobalValue>(Entry)->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)"). Start by making a new function of the
// correct type, RAUW, then steal the name.
GlobalDeclMap.erase(getMangledName(D));
llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(D, Ty));
NewFn->takeName(cast<llvm::GlobalValue>(Entry));
// Replace uses of F with the Function we will endow with a body.
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(NewFn, Entry->getType());
Entry->replaceAllUsesWith(NewPtrForOldDecl);
// Ok, delete the old function now, which is dead.
cast<llvm::GlobalValue>(Entry)->eraseFromParent();
Entry = NewFn;
llvm::Function *Fn = cast<llvm::Function>(Entry);
CodeGenFunction(*this).GenerateCode(D, Fn);
SetFunctionAttributesForDefinition(D, Fn);
if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
AddGlobalCtor(Fn, CA->getPriority());
if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
AddGlobalDtor(Fn, DA->getPriority());
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void CodeGenModule::EmitAliasDefinition(const ValueDecl *D) {
const AliasAttr *AA = D->getAttr<AliasAttr>();
assert(AA && "Not an alias?");
const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
// Unique the name through the identifier table.
const char *AliaseeName = AA->getAliasee().c_str();
AliaseeName = getContext().Idents.get(AliaseeName).getName();
// 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(AliaseeName, DeclTy, 0);
else
Aliasee = GetOrCreateLLVMGlobal(AliaseeName,
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());
// See if there is already something with the alias' name in the module.
const char *MangledName = getMangledName(D);
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry && !Entry->isDeclaration()) {
// 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.
GA->eraseFromParent();
return;
}
if (Entry) {
// 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.
Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA,
Entry->getType()));
Entry->eraseFromParent();
}
// Now we know that there is no conflict, set the name.
Entry = GA;
GA->setName(MangledName);
// Alias should never be internal or inline.
SetGlobalValueAttributes(D, false, false, GA, true);
}
/// getBuiltinLibFunction - Given a builtin id for a function like
/// "__builtin_fabsf", return a Function* for "fabsf".
llvm::Value *CodeGenModule::getBuiltinLibFunction(unsigned BuiltinID) {
assert((Context.BuiltinInfo.isLibFunction(BuiltinID) ||
Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) &&
"isn't a lib fn");
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// Get the name, skip over the __builtin_ prefix (if necessary).
const char *Name = Context.BuiltinInfo.GetName(BuiltinID);
if (Context.BuiltinInfo.isLibFunction(BuiltinID))
Name += 10;
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// Get the type for the builtin.
Builtin::Context::GetBuiltinTypeError Error;
QualType Type = Context.BuiltinInfo.GetBuiltinType(BuiltinID, Context, Error);
assert(Error == Builtin::Context::GE_None && "Can't get builtin type");
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const llvm::FunctionType *Ty =
cast<llvm::FunctionType>(getTypes().ConvertType(Type));
// Unique the name through the identifier table.
Name = getContext().Idents.get(Name).getName();
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// FIXME: param attributes for sext/zext etc.
return GetOrCreateLLVMFunction(Name, Ty, 0);
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}
llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys,
unsigned NumTys) {
return llvm::Intrinsic::getDeclaration(&getModule(),
(llvm::Intrinsic::ID)IID, Tys, NumTys);