blob: 7877baaf3ecf942c741d7e83bed5171f18d87cca [file] [log] [blame]
//===------- CGObjCGNU.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 provides Objective-C code generation targetting the GNU runtime. The
// class in this file generates structures used by the GNU Objective-C runtime
// library. These structures are defined in objc/objc.h and objc/objc-api.h in
// the GNU runtime distribution.
//
//===----------------------------------------------------------------------===//
#include "CGObjCRuntime.h"
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "llvm/Module.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Target/TargetData.h"
#include <map>
using namespace clang;
using namespace CodeGen;
using llvm::dyn_cast;
// The version of the runtime that this class targets. Must match the version
// in the runtime.
static const int RuntimeVersion = 8;
static const int ProtocolVersion = 2;
namespace {
class CGObjCGNU : public CodeGen::CGObjCRuntime {
private:
CodeGen::CodeGenModule &CGM;
llvm::Module &TheModule;
const llvm::PointerType *SelectorTy;
const llvm::PointerType *PtrToInt8Ty;
const llvm::FunctionType *IMPTy;
const llvm::PointerType *IdTy;
const llvm::IntegerType *IntTy;
const llvm::PointerType *PtrTy;
const llvm::IntegerType *LongTy;
const llvm::PointerType *PtrToIntTy;
std::vector<llvm::Constant*> Classes;
std::vector<llvm::Constant*> Categories;
std::vector<llvm::Constant*> ConstantStrings;
llvm::Function *LoadFunction;
llvm::StringMap<llvm::Constant*> ExistingProtocols;
typedef std::pair<std::string, std::string> TypedSelector;
std::map<TypedSelector, llvm::GlobalAlias*> TypedSelectors;
llvm::StringMap<llvm::GlobalAlias*> UntypedSelectors;
// Some zeros used for GEPs in lots of places.
llvm::Constant *Zeros[2];
llvm::Constant *NULLPtr;
private:
llvm::Constant *GenerateIvarList(
const llvm::SmallVectorImpl<llvm::Constant *> &IvarNames,
const llvm::SmallVectorImpl<llvm::Constant *> &IvarTypes,
const llvm::SmallVectorImpl<llvm::Constant *> &IvarOffsets);
llvm::Constant *GenerateMethodList(const std::string &ClassName,
const std::string &CategoryName,
const llvm::SmallVectorImpl<Selector> &MethodSels,
const llvm::SmallVectorImpl<llvm::Constant *> &MethodTypes,
bool isClassMethodList);
llvm::Constant *GenerateProtocolList(
const llvm::SmallVectorImpl<std::string> &Protocols);
llvm::Constant *GenerateClassStructure(
llvm::Constant *MetaClass,
llvm::Constant *SuperClass,
unsigned info,
const char *Name,
llvm::Constant *Version,
llvm::Constant *InstanceSize,
llvm::Constant *IVars,
llvm::Constant *Methods,
llvm::Constant *Protocols);
llvm::Constant *GenerateProtocolMethodList(
const llvm::SmallVectorImpl<llvm::Constant *> &MethodNames,
const llvm::SmallVectorImpl<llvm::Constant *> &MethodTypes);
llvm::Constant *MakeConstantString(const std::string &Str, const std::string
&Name="");
llvm::Constant *MakeGlobal(const llvm::StructType *Ty,
std::vector<llvm::Constant*> &V, const std::string &Name="");
llvm::Constant *MakeGlobal(const llvm::ArrayType *Ty,
std::vector<llvm::Constant*> &V, const std::string &Name="");
public:
CGObjCGNU(CodeGen::CodeGenModule &cgm);
virtual llvm::Constant *GenerateConstantString(const std::string &String);
virtual CodeGen::RValue
GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
QualType ResultType,
Selector Sel,
llvm::Value *Receiver,
bool IsClassMessage,
const CallArgList &CallArgs);
virtual CodeGen::RValue
GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
QualType ResultType,
Selector Sel,
const ObjCInterfaceDecl *Class,
bool isCategoryImpl,
llvm::Value *Receiver,
bool IsClassMessage,
const CallArgList &CallArgs);
virtual llvm::Value *GetClass(CGBuilderTy &Builder,
const ObjCInterfaceDecl *OID);
virtual llvm::Value *GetSelector(CGBuilderTy &Builder, Selector Sel);
virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD);
virtual void GenerateCategory(const ObjCCategoryImplDecl *CMD);
virtual void GenerateClass(const ObjCImplementationDecl *ClassDecl);
virtual llvm::Value *GenerateProtocolRef(CGBuilderTy &Builder,
const ObjCProtocolDecl *PD);
virtual void GenerateProtocol(const ObjCProtocolDecl *PD);
virtual llvm::Function *ModuleInitFunction();
virtual llvm::Function *GetPropertyGetFunction();
virtual llvm::Function *GetPropertySetFunction();
virtual llvm::Function *EnumerationMutationFunction();
virtual void EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
const Stmt &S);
virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtThrowStmt &S);
virtual llvm::Value * EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
llvm::Value *AddrWeakObj);
virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dst);
virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dest);
virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dest);
virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dest);
virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
QualType ObjectTy,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
const FieldDecl *Field,
unsigned CVRQualifiers);
virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar);
};
} // end anonymous namespace
static std::string SymbolNameForClass(const std::string &ClassName) {
return ".objc_class_" + ClassName;
}
static std::string SymbolNameForMethod(const std::string &ClassName, const
std::string &CategoryName, const std::string &MethodName, bool isClassMethod)
{
return "._objc_method_" + ClassName +"("+CategoryName+")"+
(isClassMethod ? "+" : "-") + MethodName;
}
CGObjCGNU::CGObjCGNU(CodeGen::CodeGenModule &cgm)
: CGM(cgm), TheModule(CGM.getModule()) {
IntTy = cast<llvm::IntegerType>(
CGM.getTypes().ConvertType(CGM.getContext().IntTy));
LongTy = cast<llvm::IntegerType>(
CGM.getTypes().ConvertType(CGM.getContext().LongTy));
Zeros[0] = llvm::ConstantInt::get(LongTy, 0);
Zeros[1] = Zeros[0];
NULLPtr = llvm::ConstantPointerNull::get(
llvm::PointerType::getUnqual(llvm::Type::Int8Ty));
// C string type. Used in lots of places.
PtrToInt8Ty =
llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
// Get the selector Type.
SelectorTy = cast<llvm::PointerType>(
CGM.getTypes().ConvertType(CGM.getContext().getObjCSelType()));
PtrToIntTy = llvm::PointerType::getUnqual(IntTy);
PtrTy = PtrToInt8Ty;
// Object type
IdTy = cast<llvm::PointerType>(
CGM.getTypes().ConvertType(CGM.getContext().getObjCIdType()));
// IMP type
std::vector<const llvm::Type*> IMPArgs;
IMPArgs.push_back(IdTy);
IMPArgs.push_back(SelectorTy);
IMPTy = llvm::FunctionType::get(IdTy, IMPArgs, true);
}
// This has to perform the lookup every time, since posing and related
// techniques can modify the name -> class mapping.
llvm::Value *CGObjCGNU::GetClass(CGBuilderTy &Builder,
const ObjCInterfaceDecl *OID) {
llvm::Value *ClassName = CGM.GetAddrOfConstantCString(OID->getNameAsString());
ClassName = Builder.CreateStructGEP(ClassName, 0);
llvm::Constant *ClassLookupFn =
TheModule.getOrInsertFunction("objc_lookup_class", IdTy, PtrToInt8Ty,
NULL);
return Builder.CreateCall(ClassLookupFn, ClassName);
}
/// GetSelector - Return the pointer to the unique'd string for this selector.
llvm::Value *CGObjCGNU::GetSelector(CGBuilderTy &Builder, Selector Sel) {
// FIXME: uniquing on the string is wasteful, unique on Sel instead!
llvm::GlobalAlias *&US = UntypedSelectors[Sel.getAsString()];
if (US == 0)
US = new llvm::GlobalAlias(llvm::PointerType::getUnqual(SelectorTy),
llvm::GlobalValue::InternalLinkage,
".objc_untyped_selector_alias",
NULL, &TheModule);
return Builder.CreateLoad(US);
}
llvm::Constant *CGObjCGNU::MakeConstantString(const std::string &Str,
const std::string &Name) {
llvm::Constant * ConstStr = llvm::ConstantArray::get(Str);
ConstStr = new llvm::GlobalVariable(ConstStr->getType(), true,
llvm::GlobalValue::InternalLinkage,
ConstStr, Name, &TheModule);
return llvm::ConstantExpr::getGetElementPtr(ConstStr, Zeros, 2);
}
llvm::Constant *CGObjCGNU::MakeGlobal(const llvm::StructType *Ty,
std::vector<llvm::Constant*> &V, const std::string &Name) {
llvm::Constant *C = llvm::ConstantStruct::get(Ty, V);
return new llvm::GlobalVariable(Ty, false,
llvm::GlobalValue::InternalLinkage, C, Name, &TheModule);
}
llvm::Constant *CGObjCGNU::MakeGlobal(const llvm::ArrayType *Ty,
std::vector<llvm::Constant*> &V, const std::string &Name) {
llvm::Constant *C = llvm::ConstantArray::get(Ty, V);
return new llvm::GlobalVariable(Ty, false,
llvm::GlobalValue::InternalLinkage, C, Name, &TheModule);
}
/// Generate an NSConstantString object.
//TODO: In case there are any crazy people still using the GNU runtime without
//an OpenStep implementation, this should let them select their own class for
//constant strings.
llvm::Constant *CGObjCGNU::GenerateConstantString(const std::string &Str) {
std::vector<llvm::Constant*> Ivars;
Ivars.push_back(NULLPtr);
Ivars.push_back(MakeConstantString(Str));
Ivars.push_back(llvm::ConstantInt::get(IntTy, Str.size()));
llvm::Constant *ObjCStr = MakeGlobal(
llvm::StructType::get(PtrToInt8Ty, PtrToInt8Ty, IntTy, NULL),
Ivars, ".objc_str");
ConstantStrings.push_back(
llvm::ConstantExpr::getBitCast(ObjCStr, PtrToInt8Ty));
return ObjCStr;
}
///Generates a message send where the super is the receiver. This is a message
///send to self with special delivery semantics indicating which class's method
///should be called.
CodeGen::RValue
CGObjCGNU::GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
QualType ResultType,
Selector Sel,
const ObjCInterfaceDecl *Class,
bool isCategoryImpl,
llvm::Value *Receiver,
bool IsClassMessage,
const CallArgList &CallArgs) {
llvm::Value *cmd = GetSelector(CGF.Builder, Sel);
CallArgList ActualArgs;
ActualArgs.push_back(
std::make_pair(RValue::get(CGF.Builder.CreateBitCast(Receiver, IdTy)),
CGF.getContext().getObjCIdType()));
ActualArgs.push_back(std::make_pair(RValue::get(cmd),
CGF.getContext().getObjCSelType()));
ActualArgs.insert(ActualArgs.end(), CallArgs.begin(), CallArgs.end());
CodeGenTypes &Types = CGM.getTypes();
const CGFunctionInfo &FnInfo = Types.getFunctionInfo(ResultType, ActualArgs);
const llvm::FunctionType *impType = Types.GetFunctionType(FnInfo, false);
const ObjCInterfaceDecl *SuperClass = Class->getSuperClass();
// TODO: This should be cached, not looked up every time.
llvm::Value *ReceiverClass = GetClass(CGF.Builder, SuperClass);
// Construct the structure used to look up the IMP
llvm::StructType *ObjCSuperTy = llvm::StructType::get(Receiver->getType(),
IdTy, NULL);
llvm::Value *ObjCSuper = CGF.Builder.CreateAlloca(ObjCSuperTy);
CGF.Builder.CreateStore(Receiver, CGF.Builder.CreateStructGEP(ObjCSuper, 0));
CGF.Builder.CreateStore(ReceiverClass, CGF.Builder.CreateStructGEP(ObjCSuper, 1));
// Get the IMP
llvm::Constant *lookupFunction =
TheModule.getOrInsertFunction("objc_msg_lookup_super",
llvm::PointerType::getUnqual(impType),
llvm::PointerType::getUnqual(ObjCSuperTy),
SelectorTy, NULL);
llvm::Value *lookupArgs[] = {ObjCSuper, cmd};
llvm::Value *imp = CGF.Builder.CreateCall(lookupFunction, lookupArgs,
lookupArgs+2);
return CGF.EmitCall(FnInfo, imp, ActualArgs);
}
/// Generate code for a message send expression.
CodeGen::RValue
CGObjCGNU::GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
QualType ResultType,
Selector Sel,
llvm::Value *Receiver,
bool IsClassMessage,
const CallArgList &CallArgs) {
llvm::Value *cmd = GetSelector(CGF.Builder, Sel);
CallArgList ActualArgs;
ActualArgs.push_back(
std::make_pair(RValue::get(CGF.Builder.CreateBitCast(Receiver, IdTy)),
CGF.getContext().getObjCIdType()));
ActualArgs.push_back(std::make_pair(RValue::get(cmd),
CGF.getContext().getObjCSelType()));
ActualArgs.insert(ActualArgs.end(), CallArgs.begin(), CallArgs.end());
CodeGenTypes &Types = CGM.getTypes();
const CGFunctionInfo &FnInfo = Types.getFunctionInfo(ResultType, ActualArgs);
const llvm::FunctionType *impType = Types.GetFunctionType(FnInfo, false);
llvm::Constant *lookupFunction =
TheModule.getOrInsertFunction("objc_msg_lookup",
llvm::PointerType::getUnqual(impType),
Receiver->getType(), SelectorTy, NULL);
llvm::Value *imp = CGF.Builder.CreateCall2(lookupFunction, Receiver, cmd);
return CGF.EmitCall(FnInfo, imp, ActualArgs);
}
/// Generates a MethodList. Used in construction of a objc_class and
/// objc_category structures.
llvm::Constant *CGObjCGNU::GenerateMethodList(const std::string &ClassName,
const std::string &CategoryName,
const llvm::SmallVectorImpl<Selector> &MethodSels,
const llvm::SmallVectorImpl<llvm::Constant *> &MethodTypes,
bool isClassMethodList) {
// Get the method structure type.
llvm::StructType *ObjCMethodTy = llvm::StructType::get(
PtrToInt8Ty, // Really a selector, but the runtime creates it us.
PtrToInt8Ty, // Method types
llvm::PointerType::getUnqual(IMPTy), //Method pointer
NULL);
std::vector<llvm::Constant*> Methods;
std::vector<llvm::Constant*> Elements;
for (unsigned int i = 0, e = MethodTypes.size(); i < e; ++i) {
Elements.clear();
llvm::Constant *C =
CGM.GetAddrOfConstantCString(MethodSels[i].getAsString());
Elements.push_back(llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2));
Elements.push_back(
llvm::ConstantExpr::getGetElementPtr(MethodTypes[i], Zeros, 2));
llvm::Constant *Method =
TheModule.getFunction(SymbolNameForMethod(ClassName, CategoryName,
MethodSels[i].getAsString(),
isClassMethodList));
Method = llvm::ConstantExpr::getBitCast(Method,
llvm::PointerType::getUnqual(IMPTy));
Elements.push_back(Method);
Methods.push_back(llvm::ConstantStruct::get(ObjCMethodTy, Elements));
}
// Array of method structures
llvm::ArrayType *ObjCMethodArrayTy = llvm::ArrayType::get(ObjCMethodTy,
MethodSels.size());
llvm::Constant *MethodArray = llvm::ConstantArray::get(ObjCMethodArrayTy,
Methods);
// Structure containing list pointer, array and array count
llvm::SmallVector<const llvm::Type*, 16> ObjCMethodListFields;
llvm::PATypeHolder OpaqueNextTy = llvm::OpaqueType::get();
llvm::Type *NextPtrTy = llvm::PointerType::getUnqual(OpaqueNextTy);
llvm::StructType *ObjCMethodListTy = llvm::StructType::get(NextPtrTy,
IntTy,
ObjCMethodArrayTy,
NULL);
// Refine next pointer type to concrete type
llvm::cast<llvm::OpaqueType>(
OpaqueNextTy.get())->refineAbstractTypeTo(ObjCMethodListTy);
ObjCMethodListTy = llvm::cast<llvm::StructType>(OpaqueNextTy.get());
Methods.clear();
Methods.push_back(llvm::ConstantPointerNull::get(
llvm::PointerType::getUnqual(ObjCMethodListTy)));
Methods.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty,
MethodTypes.size()));
Methods.push_back(MethodArray);
// Create an instance of the structure
return MakeGlobal(ObjCMethodListTy, Methods, ".objc_method_list");
}
/// Generates an IvarList. Used in construction of a objc_class.
llvm::Constant *CGObjCGNU::GenerateIvarList(
const llvm::SmallVectorImpl<llvm::Constant *> &IvarNames,
const llvm::SmallVectorImpl<llvm::Constant *> &IvarTypes,
const llvm::SmallVectorImpl<llvm::Constant *> &IvarOffsets) {
// Get the method structure type.
llvm::StructType *ObjCIvarTy = llvm::StructType::get(
PtrToInt8Ty,
PtrToInt8Ty,
IntTy,
NULL);
std::vector<llvm::Constant*> Ivars;
std::vector<llvm::Constant*> Elements;
for (unsigned int i = 0, e = IvarNames.size() ; i < e ; i++) {
Elements.clear();
Elements.push_back( llvm::ConstantExpr::getGetElementPtr(IvarNames[i],
Zeros, 2));
Elements.push_back( llvm::ConstantExpr::getGetElementPtr(IvarTypes[i],
Zeros, 2));
Elements.push_back(IvarOffsets[i]);
Ivars.push_back(llvm::ConstantStruct::get(ObjCIvarTy, Elements));
}
// Array of method structures
llvm::ArrayType *ObjCIvarArrayTy = llvm::ArrayType::get(ObjCIvarTy,
IvarNames.size());
Elements.clear();
Elements.push_back(llvm::ConstantInt::get(IntTy, (int)IvarNames.size()));
Elements.push_back(llvm::ConstantArray::get(ObjCIvarArrayTy, Ivars));
// Structure containing array and array count
llvm::StructType *ObjCIvarListTy = llvm::StructType::get(IntTy,
ObjCIvarArrayTy,
NULL);
// Create an instance of the structure
return MakeGlobal(ObjCIvarListTy, Elements, ".objc_ivar_list");
}
/// Generate a class structure
llvm::Constant *CGObjCGNU::GenerateClassStructure(
llvm::Constant *MetaClass,
llvm::Constant *SuperClass,
unsigned info,
const char *Name,
llvm::Constant *Version,
llvm::Constant *InstanceSize,
llvm::Constant *IVars,
llvm::Constant *Methods,
llvm::Constant *Protocols) {
// Set up the class structure
// Note: Several of these are char*s when they should be ids. This is
// because the runtime performs this translation on load.
llvm::StructType *ClassTy = llvm::StructType::get(
PtrToInt8Ty, // class_pointer
PtrToInt8Ty, // super_class
PtrToInt8Ty, // name
LongTy, // version
LongTy, // info
LongTy, // instance_size
IVars->getType(), // ivars
Methods->getType(), // methods
// These are all filled in by the runtime, so we pretend
PtrTy, // dtable
PtrTy, // subclass_list
PtrTy, // sibling_class
PtrTy, // protocols
PtrTy, // gc_object_type
NULL);
llvm::Constant *Zero = llvm::ConstantInt::get(LongTy, 0);
llvm::Constant *NullP =
llvm::ConstantPointerNull::get(PtrTy);
// Fill in the structure
std::vector<llvm::Constant*> Elements;
Elements.push_back(llvm::ConstantExpr::getBitCast(MetaClass, PtrToInt8Ty));
Elements.push_back(SuperClass);
Elements.push_back(MakeConstantString(Name, ".class_name"));
Elements.push_back(Zero);
Elements.push_back(llvm::ConstantInt::get(LongTy, info));
Elements.push_back(InstanceSize);
Elements.push_back(IVars);
Elements.push_back(Methods);
Elements.push_back(NullP);
Elements.push_back(NullP);
Elements.push_back(NullP);
Elements.push_back(llvm::ConstantExpr::getBitCast(Protocols, PtrTy));
Elements.push_back(NullP);
// Create an instance of the structure
return MakeGlobal(ClassTy, Elements, SymbolNameForClass(Name));
}
llvm::Constant *CGObjCGNU::GenerateProtocolMethodList(
const llvm::SmallVectorImpl<llvm::Constant *> &MethodNames,
const llvm::SmallVectorImpl<llvm::Constant *> &MethodTypes) {
// Get the method structure type.
llvm::StructType *ObjCMethodDescTy = llvm::StructType::get(
PtrToInt8Ty, // Really a selector, but the runtime does the casting for us.
PtrToInt8Ty,
NULL);
std::vector<llvm::Constant*> Methods;
std::vector<llvm::Constant*> Elements;
for (unsigned int i = 0, e = MethodTypes.size() ; i < e ; i++) {
Elements.clear();
Elements.push_back( llvm::ConstantExpr::getGetElementPtr(MethodNames[i],
Zeros, 2));
Elements.push_back(
llvm::ConstantExpr::getGetElementPtr(MethodTypes[i], Zeros, 2));
Methods.push_back(llvm::ConstantStruct::get(ObjCMethodDescTy, Elements));
}
llvm::ArrayType *ObjCMethodArrayTy = llvm::ArrayType::get(ObjCMethodDescTy,
MethodNames.size());
llvm::Constant *Array = llvm::ConstantArray::get(ObjCMethodArrayTy, Methods);
llvm::StructType *ObjCMethodDescListTy = llvm::StructType::get(
IntTy, ObjCMethodArrayTy, NULL);
Methods.clear();
Methods.push_back(llvm::ConstantInt::get(IntTy, MethodNames.size()));
Methods.push_back(Array);
return MakeGlobal(ObjCMethodDescListTy, Methods, ".objc_method_list");
}
// Create the protocol list structure used in classes, categories and so on
llvm::Constant *CGObjCGNU::GenerateProtocolList(
const llvm::SmallVectorImpl<std::string> &Protocols) {
llvm::ArrayType *ProtocolArrayTy = llvm::ArrayType::get(PtrToInt8Ty,
Protocols.size());
llvm::StructType *ProtocolListTy = llvm::StructType::get(
PtrTy, //Should be a recurisve pointer, but it's always NULL here.
LongTy,//FIXME: Should be size_t
ProtocolArrayTy,
NULL);
std::vector<llvm::Constant*> Elements;
for (const std::string *iter = Protocols.begin(), *endIter = Protocols.end();
iter != endIter ; iter++) {
llvm::Constant *Ptr =
llvm::ConstantExpr::getBitCast(ExistingProtocols[*iter], PtrToInt8Ty);
Elements.push_back(Ptr);
}
llvm::Constant * ProtocolArray = llvm::ConstantArray::get(ProtocolArrayTy,
Elements);
Elements.clear();
Elements.push_back(NULLPtr);
Elements.push_back(llvm::ConstantInt::get(LongTy, Protocols.size()));
Elements.push_back(ProtocolArray);
return MakeGlobal(ProtocolListTy, Elements, ".objc_protocol_list");
}
llvm::Value *CGObjCGNU::GenerateProtocolRef(CGBuilderTy &Builder,
const ObjCProtocolDecl *PD) {
return ExistingProtocols[PD->getNameAsString()];
}
void CGObjCGNU::GenerateProtocol(const ObjCProtocolDecl *PD) {
ASTContext &Context = CGM.getContext();
std::string ProtocolName = PD->getNameAsString();
llvm::SmallVector<std::string, 16> Protocols;
for (ObjCProtocolDecl::protocol_iterator PI = PD->protocol_begin(),
E = PD->protocol_end(); PI != E; ++PI)
Protocols.push_back((*PI)->getNameAsString());
llvm::SmallVector<llvm::Constant*, 16> InstanceMethodNames;
llvm::SmallVector<llvm::Constant*, 16> InstanceMethodTypes;
for (ObjCProtocolDecl::instmeth_iterator iter = PD->instmeth_begin(),
E = PD->instmeth_end(); iter != E; iter++) {
std::string TypeStr;
Context.getObjCEncodingForMethodDecl(*iter, TypeStr);
InstanceMethodNames.push_back(
CGM.GetAddrOfConstantCString((*iter)->getSelector().getAsString()));
InstanceMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
// Collect information about class methods:
llvm::SmallVector<llvm::Constant*, 16> ClassMethodNames;
llvm::SmallVector<llvm::Constant*, 16> ClassMethodTypes;
for (ObjCProtocolDecl::classmeth_iterator iter = PD->classmeth_begin(),
endIter = PD->classmeth_end() ; iter != endIter ; iter++) {
std::string TypeStr;
Context.getObjCEncodingForMethodDecl((*iter),TypeStr);
ClassMethodNames.push_back(
CGM.GetAddrOfConstantCString((*iter)->getSelector().getAsString()));
ClassMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
llvm::Constant *ProtocolList = GenerateProtocolList(Protocols);
llvm::Constant *InstanceMethodList =
GenerateProtocolMethodList(InstanceMethodNames, InstanceMethodTypes);
llvm::Constant *ClassMethodList =
GenerateProtocolMethodList(ClassMethodNames, ClassMethodTypes);
// Protocols are objects containing lists of the methods implemented and
// protocols adopted.
llvm::StructType *ProtocolTy = llvm::StructType::get(IdTy,
PtrToInt8Ty,
ProtocolList->getType(),
InstanceMethodList->getType(),
ClassMethodList->getType(),
NULL);
std::vector<llvm::Constant*> Elements;
// The isa pointer must be set to a magic number so the runtime knows it's
// the correct layout.
Elements.push_back(llvm::ConstantExpr::getIntToPtr(
llvm::ConstantInt::get(llvm::Type::Int32Ty, ProtocolVersion), IdTy));
Elements.push_back(MakeConstantString(ProtocolName, ".objc_protocol_name"));
Elements.push_back(ProtocolList);
Elements.push_back(InstanceMethodList);
Elements.push_back(ClassMethodList);
ExistingProtocols[ProtocolName] =
llvm::ConstantExpr::getBitCast(MakeGlobal(ProtocolTy, Elements,
".objc_protocol"), IdTy);
}
void CGObjCGNU::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
std::string ClassName = OCD->getClassInterface()->getNameAsString();
std::string CategoryName = OCD->getNameAsString();
// Collect information about instance methods
llvm::SmallVector<Selector, 16> InstanceMethodSels;
llvm::SmallVector<llvm::Constant*, 16> InstanceMethodTypes;
for (ObjCCategoryImplDecl::instmeth_iterator iter = OCD->instmeth_begin(),
endIter = OCD->instmeth_end() ; iter != endIter ; iter++) {
InstanceMethodSels.push_back((*iter)->getSelector());
std::string TypeStr;
CGM.getContext().getObjCEncodingForMethodDecl(*iter,TypeStr);
InstanceMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
// Collect information about class methods
llvm::SmallVector<Selector, 16> ClassMethodSels;
llvm::SmallVector<llvm::Constant*, 16> ClassMethodTypes;
for (ObjCCategoryImplDecl::classmeth_iterator iter = OCD->classmeth_begin(),
endIter = OCD->classmeth_end() ; iter != endIter ; iter++) {
ClassMethodSels.push_back((*iter)->getSelector());
std::string TypeStr;
CGM.getContext().getObjCEncodingForMethodDecl(*iter,TypeStr);
ClassMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
// Collect the names of referenced protocols
llvm::SmallVector<std::string, 16> Protocols;
const ObjCInterfaceDecl *ClassDecl = OCD->getClassInterface();
const ObjCList<ObjCProtocolDecl> &Protos =ClassDecl->getReferencedProtocols();
for (ObjCList<ObjCProtocolDecl>::iterator I = Protos.begin(),
E = Protos.end(); I != E; ++I)
Protocols.push_back((*I)->getNameAsString());
std::vector<llvm::Constant*> Elements;
Elements.push_back(MakeConstantString(CategoryName));
Elements.push_back(MakeConstantString(ClassName));
// Instance method list
Elements.push_back(llvm::ConstantExpr::getBitCast(GenerateMethodList(
ClassName, CategoryName, InstanceMethodSels, InstanceMethodTypes,
false), PtrTy));
// Class method list
Elements.push_back(llvm::ConstantExpr::getBitCast(GenerateMethodList(
ClassName, CategoryName, ClassMethodSels, ClassMethodTypes, true),
PtrTy));
// Protocol list
Elements.push_back(llvm::ConstantExpr::getBitCast(
GenerateProtocolList(Protocols), PtrTy));
Categories.push_back(llvm::ConstantExpr::getBitCast(
MakeGlobal(llvm::StructType::get(PtrToInt8Ty, PtrToInt8Ty, PtrTy,
PtrTy, PtrTy, NULL), Elements), PtrTy));
}
void CGObjCGNU::GenerateClass(const ObjCImplementationDecl *OID) {
ASTContext &Context = CGM.getContext();
// Get the superclass name.
const ObjCInterfaceDecl * SuperClassDecl =
OID->getClassInterface()->getSuperClass();
std::string SuperClassName;
if (SuperClassDecl)
SuperClassName = SuperClassDecl->getNameAsString();
// Get the class name
ObjCInterfaceDecl * ClassDecl = (ObjCInterfaceDecl*)OID->getClassInterface();
std::string ClassName = ClassDecl->getNameAsString();
// Get the size of instances. For runtimes that support late-bound instances
// this should probably be something different (size just of instance
// varaibles in this class, not superclasses?).
int instanceSize = 0;
const llvm::Type *ObjTy = 0;
if (!LateBoundIVars()) {
ObjTy = CGM.getTypes().ConvertType(Context.getObjCInterfaceType(ClassDecl));
instanceSize = CGM.getTargetData().getTypePaddedSize(ObjTy);
} else {
// This is required by newer ObjC runtimes.
assert(0 && "Late-bound instance variables not yet supported");
}
// Collect information about instance variables.
llvm::SmallVector<llvm::Constant*, 16> IvarNames;
llvm::SmallVector<llvm::Constant*, 16> IvarTypes;
llvm::SmallVector<llvm::Constant*, 16> IvarOffsets;
const llvm::StructLayout *Layout =
CGM.getTargetData().getStructLayout(cast<llvm::StructType>(ObjTy));
ObjTy = llvm::PointerType::getUnqual(ObjTy);
for (ObjCInterfaceDecl::ivar_iterator iter = ClassDecl->ivar_begin(),
endIter = ClassDecl->ivar_end() ; iter != endIter ; iter++) {
// Store the name
IvarNames.push_back(CGM.GetAddrOfConstantCString((*iter)
->getNameAsString()));
// Get the type encoding for this ivar
std::string TypeStr;
Context.getObjCEncodingForType((*iter)->getType(), TypeStr);
IvarTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
// Get the offset
FieldDecl *Field = ClassDecl->lookupFieldDeclForIvar(Context, (*iter));
int offset =
(int)Layout->getElementOffset(CGM.getTypes().getLLVMFieldNo(Field));
IvarOffsets.push_back(
llvm::ConstantInt::get(llvm::Type::Int32Ty, offset));
}
// Collect information about instance methods
llvm::SmallVector<Selector, 16> InstanceMethodSels;
llvm::SmallVector<llvm::Constant*, 16> InstanceMethodTypes;
for (ObjCImplementationDecl::instmeth_iterator iter = OID->instmeth_begin(),
endIter = OID->instmeth_end() ; iter != endIter ; iter++) {
InstanceMethodSels.push_back((*iter)->getSelector());
std::string TypeStr;
Context.getObjCEncodingForMethodDecl((*iter),TypeStr);
InstanceMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
// Collect information about class methods
llvm::SmallVector<Selector, 16> ClassMethodSels;
llvm::SmallVector<llvm::Constant*, 16> ClassMethodTypes;
for (ObjCImplementationDecl::classmeth_iterator iter = OID->classmeth_begin(),
endIter = OID->classmeth_end() ; iter != endIter ; iter++) {
ClassMethodSels.push_back((*iter)->getSelector());
std::string TypeStr;
Context.getObjCEncodingForMethodDecl((*iter),TypeStr);
ClassMethodTypes.push_back(CGM.GetAddrOfConstantCString(TypeStr));
}
// Collect the names of referenced protocols
llvm::SmallVector<std::string, 16> Protocols;
const ObjCList<ObjCProtocolDecl> &Protos =ClassDecl->getReferencedProtocols();
for (ObjCList<ObjCProtocolDecl>::iterator I = Protos.begin(),
E = Protos.end(); I != E; ++I)
Protocols.push_back((*I)->getNameAsString());
// Get the superclass pointer.
llvm::Constant *SuperClass;
if (!SuperClassName.empty()) {
SuperClass = MakeConstantString(SuperClassName, ".super_class_name");
} else {
SuperClass = llvm::ConstantPointerNull::get(PtrToInt8Ty);
}
// Empty vector used to construct empty method lists
llvm::SmallVector<llvm::Constant*, 1> empty;
// Generate the method and instance variable lists
llvm::Constant *MethodList = GenerateMethodList(ClassName, "",
InstanceMethodSels, InstanceMethodTypes, false);
llvm::Constant *ClassMethodList = GenerateMethodList(ClassName, "",
ClassMethodSels, ClassMethodTypes, true);
llvm::Constant *IvarList = GenerateIvarList(IvarNames, IvarTypes,
IvarOffsets);
//Generate metaclass for class methods
llvm::Constant *MetaClassStruct = GenerateClassStructure(NULLPtr,
NULLPtr, 0x2L, /*name*/"", 0, Zeros[0], GenerateIvarList(
empty, empty, empty), ClassMethodList, NULLPtr);
// Generate the class structure
llvm::Constant *ClassStruct =
GenerateClassStructure(MetaClassStruct, SuperClass, 0x1L,
ClassName.c_str(), 0,
llvm::ConstantInt::get(LongTy, instanceSize), IvarList,
MethodList, GenerateProtocolList(Protocols));
// Add class structure to list to be added to the symtab later
ClassStruct = llvm::ConstantExpr::getBitCast(ClassStruct, PtrToInt8Ty);
Classes.push_back(ClassStruct);
}
llvm::Function *CGObjCGNU::ModuleInitFunction() {
// Only emit an ObjC load function if no Objective-C stuff has been called
if (Classes.empty() && Categories.empty() && ConstantStrings.empty() &&
ExistingProtocols.empty() && TypedSelectors.empty() &&
UntypedSelectors.empty())
return NULL;
const llvm::StructType *SelStructTy = dyn_cast<llvm::StructType>(
SelectorTy->getElementType());
const llvm::Type *SelStructPtrTy = SelectorTy;
bool isSelOpaque = false;
if (SelStructTy == 0) {
SelStructTy = llvm::StructType::get(PtrToInt8Ty, PtrToInt8Ty, NULL);
SelStructPtrTy = llvm::PointerType::getUnqual(SelStructTy);
isSelOpaque = true;
}
// Name the ObjC types to make the IR a bit easier to read
TheModule.addTypeName(".objc_selector", SelStructPtrTy);
TheModule.addTypeName(".objc_id", IdTy);
TheModule.addTypeName(".objc_imp", IMPTy);
std::vector<llvm::Constant*> Elements;
// Generate statics list:
llvm::ArrayType *StaticsArrayTy = llvm::ArrayType::get(PtrToInt8Ty,
ConstantStrings.size() + 1);
ConstantStrings.push_back(NULLPtr);
Elements.push_back(MakeConstantString("NSConstantString",
".objc_static_class_name"));
Elements.push_back(llvm::ConstantArray::get(StaticsArrayTy, ConstantStrings));
llvm::StructType *StaticsListTy =
llvm::StructType::get(PtrToInt8Ty, StaticsArrayTy, NULL);
llvm::Type *StaticsListPtrTy = llvm::PointerType::getUnqual(StaticsListTy);
llvm::Constant *Statics =
MakeGlobal(StaticsListTy, Elements, ".objc_statics");
llvm::ArrayType *StaticsListArrayTy =
llvm::ArrayType::get(StaticsListPtrTy, 2);
Elements.clear();
Elements.push_back(Statics);
Elements.push_back(llvm::Constant::getNullValue(StaticsListPtrTy));
Statics = MakeGlobal(StaticsListArrayTy, Elements, ".objc_statics_ptr");
Statics = llvm::ConstantExpr::getBitCast(Statics, PtrTy);
// Array of classes, categories, and constant objects
llvm::ArrayType *ClassListTy = llvm::ArrayType::get(PtrToInt8Ty,
Classes.size() + Categories.size() + 2);
llvm::StructType *SymTabTy = llvm::StructType::get(LongTy, SelStructPtrTy,
llvm::Type::Int16Ty,
llvm::Type::Int16Ty,
ClassListTy, NULL);
Elements.clear();
// Pointer to an array of selectors used in this module.
std::vector<llvm::Constant*> Selectors;
for (std::map<TypedSelector, llvm::GlobalAlias*>::iterator
iter = TypedSelectors.begin(), iterEnd = TypedSelectors.end();
iter != iterEnd ; ++iter) {
Elements.push_back(MakeConstantString(iter->first.first, ".objc_sel_name"));
Elements.push_back(MakeConstantString(iter->first.second,
".objc_sel_types"));
Selectors.push_back(llvm::ConstantStruct::get(SelStructTy, Elements));
Elements.clear();
}
for (llvm::StringMap<llvm::GlobalAlias*>::iterator
iter = UntypedSelectors.begin(), iterEnd = UntypedSelectors.end();
iter != iterEnd; ++iter) {
Elements.push_back(
MakeConstantString(iter->getKeyData(), ".objc_sel_name"));
Elements.push_back(NULLPtr);
Selectors.push_back(llvm::ConstantStruct::get(SelStructTy, Elements));
Elements.clear();
}
Elements.push_back(NULLPtr);
Elements.push_back(NULLPtr);
Selectors.push_back(llvm::ConstantStruct::get(SelStructTy, Elements));
Elements.clear();
// Number of static selectors
Elements.push_back(llvm::ConstantInt::get(LongTy, Selectors.size() ));
llvm::Constant *SelectorList = MakeGlobal(
llvm::ArrayType::get(SelStructTy, Selectors.size()), Selectors,
".objc_selector_list");
Elements.push_back(llvm::ConstantExpr::getBitCast(SelectorList,
SelStructPtrTy));
// Now that all of the static selectors exist, create pointers to them.
int index = 0;
for (std::map<TypedSelector, llvm::GlobalAlias*>::iterator
iter=TypedSelectors.begin(), iterEnd =TypedSelectors.end();
iter != iterEnd; ++iter) {
llvm::Constant *Idxs[] = {Zeros[0],
llvm::ConstantInt::get(llvm::Type::Int32Ty, index++), Zeros[0]};
llvm::Constant *SelPtr = new llvm::GlobalVariable(SelStructPtrTy,
true, llvm::GlobalValue::InternalLinkage,
llvm::ConstantExpr::getGetElementPtr(SelectorList, Idxs, 2),
".objc_sel_ptr", &TheModule);
// If selectors are defined as an opaque type, cast the pointer to this
// type.
if (isSelOpaque) {
SelPtr = llvm::ConstantExpr::getBitCast(SelPtr,
llvm::PointerType::getUnqual(SelectorTy));
}
(*iter).second->setAliasee(SelPtr);
}
for (llvm::StringMap<llvm::GlobalAlias*>::iterator
iter=UntypedSelectors.begin(), iterEnd = UntypedSelectors.end();
iter != iterEnd; iter++) {
llvm::Constant *Idxs[] = {Zeros[0],
llvm::ConstantInt::get(llvm::Type::Int32Ty, index++), Zeros[0]};
llvm::Constant *SelPtr = new llvm::GlobalVariable(SelStructPtrTy, true,
llvm::GlobalValue::InternalLinkage,
llvm::ConstantExpr::getGetElementPtr(SelectorList, Idxs, 2),
".objc_sel_ptr", &TheModule);
// If selectors are defined as an opaque type, cast the pointer to this
// type.
if (isSelOpaque) {
SelPtr = llvm::ConstantExpr::getBitCast(SelPtr,
llvm::PointerType::getUnqual(SelectorTy));
}
(*iter).second->setAliasee(SelPtr);
}
// Number of classes defined.
Elements.push_back(llvm::ConstantInt::get(llvm::Type::Int16Ty,
Classes.size()));
// Number of categories defined
Elements.push_back(llvm::ConstantInt::get(llvm::Type::Int16Ty,
Categories.size()));
// Create an array of classes, then categories, then static object instances
Classes.insert(Classes.end(), Categories.begin(), Categories.end());
// NULL-terminated list of static object instances (mainly constant strings)
Classes.push_back(Statics);
Classes.push_back(NULLPtr);
llvm::Constant *ClassList = llvm::ConstantArray::get(ClassListTy, Classes);
Elements.push_back(ClassList);
// Construct the symbol table
llvm::Constant *SymTab= MakeGlobal(SymTabTy, Elements);
// The symbol table is contained in a module which has some version-checking
// constants
llvm::StructType * ModuleTy = llvm::StructType::get(LongTy, LongTy,
PtrToInt8Ty, llvm::PointerType::getUnqual(SymTabTy), NULL);
Elements.clear();
// Runtime version used for compatibility checking.
Elements.push_back(llvm::ConstantInt::get(LongTy, RuntimeVersion));
//FIXME: Should be sizeof(ModuleTy)
Elements.push_back(llvm::ConstantInt::get(LongTy, 16));
//FIXME: Should be the path to the file where this module was declared
Elements.push_back(NULLPtr);
Elements.push_back(SymTab);
llvm::Value *Module = MakeGlobal(ModuleTy, Elements);
// Create the load function calling the runtime entry point with the module
// structure
std::vector<const llvm::Type*> VoidArgs;
llvm::Function * LoadFunction = llvm::Function::Create(
llvm::FunctionType::get(llvm::Type::VoidTy, VoidArgs, false),
llvm::GlobalValue::InternalLinkage, ".objc_load_function",
&TheModule);
llvm::BasicBlock *EntryBB = llvm::BasicBlock::Create("entry", LoadFunction);
CGBuilderTy Builder;
Builder.SetInsertPoint(EntryBB);
llvm::Value *Register = TheModule.getOrInsertFunction("__objc_exec_class",
llvm::Type::VoidTy, llvm::PointerType::getUnqual(ModuleTy), NULL);
Builder.CreateCall(Register, Module);
Builder.CreateRetVoid();
return LoadFunction;
}
llvm::Function *CGObjCGNU::GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) {
const ObjCCategoryImplDecl *OCD =
dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext());
std::string CategoryName = OCD ? OCD->getNameAsString() : "";
std::string ClassName = OMD->getClassInterface()->getNameAsString();
std::string MethodName = OMD->getSelector().getAsString();
bool isClassMethod = !OMD->isInstanceMethod();
CodeGenTypes &Types = CGM.getTypes();
const llvm::FunctionType *MethodTy =
Types.GetFunctionType(Types.getFunctionInfo(OMD), OMD->isVariadic());
std::string FunctionName = SymbolNameForMethod(ClassName, CategoryName,
MethodName, isClassMethod);
llvm::Function *Method = llvm::Function::Create(MethodTy,
llvm::GlobalValue::InternalLinkage,
FunctionName,
&TheModule);
return Method;
}
llvm::Function *CGObjCGNU::GetPropertyGetFunction() {
return 0;
}
llvm::Function *CGObjCGNU::GetPropertySetFunction() {
return 0;
}
llvm::Function *CGObjCGNU::EnumerationMutationFunction() {
return
(llvm::Function*)TheModule.getOrInsertFunction(
"objc_enumerationMutation", llvm::Type::VoidTy, IdTy, NULL);
}
void CGObjCGNU::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
const Stmt &S) {
CGF.ErrorUnsupported(&S, "@try/@synchronized statement");
}
void CGObjCGNU::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtThrowStmt &S) {
CGF.ErrorUnsupported(&S, "@throw statement");
}
llvm::Value * CGObjCGNU::EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
llvm::Value *AddrWeakObj)
{
return 0;
}
void CGObjCGNU::EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dst)
{
return;
}
void CGObjCGNU::EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dst)
{
return;
}
void CGObjCGNU::EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dst)
{
return;
}
void CGObjCGNU::EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, llvm::Value *dst)
{
return;
}
LValue CGObjCGNU::EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
QualType ObjectTy,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
const FieldDecl *Field,
unsigned CVRQualifiers) {
if (Ivar->isBitField())
return CGF.EmitLValueForBitfield(BaseValue, const_cast<FieldDecl *>(Field),
CVRQualifiers);
// TODO: Add a special case for isa (index 0)
unsigned Index = CGM.getTypes().getLLVMFieldNo(Field);
llvm::Value *V = CGF.Builder.CreateStructGEP(BaseValue, Index, "tmp");
LValue LV = LValue::MakeAddr(V,
Ivar->getType().getCVRQualifiers()|CVRQualifiers);
LValue::SetObjCIvar(LV, true);
return LV;
}
llvm::Value *CGObjCGNU::EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) {
const llvm::Type *InterfaceLTy =
CGM.getTypes().ConvertType(
CGM.getContext().getObjCInterfaceType(Interface));
const llvm::StructLayout *Layout =
CGM.getTargetData().getStructLayout(cast<llvm::StructType>(InterfaceLTy));
FieldDecl *Field = Interface->lookupFieldDeclForIvar(CGM.getContext(), Ivar);
uint64_t Offset =
Layout->getElementOffset(CGM.getTypes().getLLVMFieldNo(Field));
return llvm::ConstantInt::get(
CGM.getTypes().ConvertType(CGM.getContext().LongTy),
Offset);
}
CodeGen::CGObjCRuntime *CodeGen::CreateGNUObjCRuntime(CodeGen::CodeGenModule &CGM){
return new CGObjCGNU(CGM);
}