lib/CodeGen/MicrosoftCXXABI.cpp - fp2-dev/platform/external/clang - Gitiles

 //===--- MicrosoftCXXABI.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 C++ code generation targeting the Microsoft Visual C++ ABI.
 // The class in this file generates structures that follow the Microsoft
 // Visual C++ ABI, which is actually not very well documented at all outside
 // of Microsoft.
 //
 //===----------------------------------------------------------------------===//

 #include "CGCXXABI.h"
 #include "CodeGenModule.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"

 using namespace clang;
 using namespace CodeGen;

 namespace {

 class MicrosoftCXXABI : public CGCXXABI {
 public:
   MicrosoftCXXABI(CodeGenModule &CGM) : CGCXXABI(CGM) {}

   StringRef GetPureVirtualCallName() { return "_purecall"; }
   // No known support for deleted functions in MSVC yet, so this choice is
   // arbitrary.
   StringRef GetDeletedVirtualCallName() { return "_purecall"; }

   llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF,
                                       llvm::Value *ptr,
                                       QualType type);

   void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
                                  CXXCtorType Type,
                                  CanQualType &ResTy,
                                  SmallVectorImpl<CanQualType> &ArgTys);

   llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF);

   void BuildDestructorSignature(const CXXDestructorDecl *Ctor,
                                 CXXDtorType Type,
                                 CanQualType &ResTy,
                                 SmallVectorImpl<CanQualType> &ArgTys);

   void BuildInstanceFunctionParams(CodeGenFunction &CGF,
                                    QualType &ResTy,
                                    FunctionArgList &Params);

   void EmitInstanceFunctionProlog(CodeGenFunction &CGF);

   llvm::Value *EmitConstructorCall(CodeGenFunction &CGF,
                            const CXXConstructorDecl *D,
                            CXXCtorType Type, bool ForVirtualBase,
                            bool Delegating,
                            llvm::Value *This,
                            CallExpr::const_arg_iterator ArgBeg,
                            CallExpr::const_arg_iterator ArgEnd);

   RValue EmitVirtualDestructorCall(CodeGenFunction &CGF,
                                    const CXXDestructorDecl *Dtor,
                                    CXXDtorType DtorType,
                                    SourceLocation CallLoc,
                                    ReturnValueSlot ReturnValue,
                                    llvm::Value *This);

   void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
                        llvm::GlobalVariable *DeclPtr,
                        bool PerformInit);

   // ==== Notes on array cookies =========
   //
   // MSVC seems to only use cookies when the class has a destructor; a
   // two-argument usual array deallocation function isn't sufficient.
   //
   // For example, this code prints "100" and "1":
   //   struct A {
   //     char x;
   //     void *operator new[](size_t sz) {
   //       printf("%u\n", sz);
   //       return malloc(sz);
   //     }
   //     void operator delete[](void *p, size_t sz) {
   //       printf("%u\n", sz);
   //       free(p);
   //     }
   //   };
   //   int main() {
   //     A *p = new A[100];
   //     delete[] p;
   //   }
   // Whereas it prints "104" and "104" if you give A a destructor.

   bool requiresArrayCookie(const CXXDeleteExpr *expr, QualType elementType);
   bool requiresArrayCookie(const CXXNewExpr *expr);
   CharUnits getArrayCookieSizeImpl(QualType type);
   llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
                                      llvm::Value *NewPtr,
                                      llvm::Value *NumElements,
                                      const CXXNewExpr *expr,
                                      QualType ElementType);
   llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
                                    llvm::Value *allocPtr,
                                    CharUnits cookieSize);
   static bool needThisReturn(GlobalDecl GD);

 private:
   llvm::Constant *getSimpleNullMemberPointer(const MemberPointerType *MPT);

   llvm::Constant *getZeroPtrDiff() {
     return llvm::ConstantInt::get(CGM.PtrDiffTy, 0);
   }

   llvm::Constant *getAllOnesPtrDiff() {
     return  llvm::Constant::getAllOnesValue(CGM.PtrDiffTy);
   }

 public:
   virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT);

   virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
                                                 CharUnits offset);

   virtual llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
                                                   llvm::Value *MemPtr,
                                                   const MemberPointerType *MPT);

   virtual llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
                                                     llvm::Value *Base,
                                                     llvm::Value *MemPtr,
                                                   const MemberPointerType *MPT);

 };

 }

 llvm::Value *MicrosoftCXXABI::adjustToCompleteObject(CodeGenFunction &CGF,
                                                      llvm::Value *ptr,
                                                      QualType type) {
   // FIXME: implement
   return ptr;
 }

 bool MicrosoftCXXABI::needThisReturn(GlobalDecl GD) {
   const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl());
   return isa<CXXConstructorDecl>(MD);
 }

 void MicrosoftCXXABI::BuildConstructorSignature(const CXXConstructorDecl *Ctor,
                                  CXXCtorType Type,
                                  CanQualType &ResTy,
                                  SmallVectorImpl<CanQualType> &ArgTys) {
   // 'this' is already in place

   // Ctor returns this ptr
   ResTy = ArgTys[0];

   const CXXRecordDecl *Class = Ctor->getParent();
   if (Class->getNumVBases()) {
     // Constructors of classes with virtual bases take an implicit parameter.
     ArgTys.push_back(CGM.getContext().IntTy);
   }
 }

 llvm::BasicBlock *MicrosoftCXXABI::EmitCtorCompleteObjectHandler(
                                                          CodeGenFunction &CGF) {
   llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
   assert(IsMostDerivedClass &&
          "ctor for a class with virtual bases must have an implicit parameter");
   llvm::Value *IsCompleteObject
     = CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");

   llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
   llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
   CGF.Builder.CreateCondBr(IsCompleteObject,
                            CallVbaseCtorsBB, SkipVbaseCtorsBB);

   CGF.EmitBlock(CallVbaseCtorsBB);
   // FIXME: emit vbtables somewhere around here.

   // CGF will put the base ctor calls in this basic block for us later.

   return SkipVbaseCtorsBB;
 }

 void MicrosoftCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor,
                                                CXXDtorType Type,
                                                CanQualType &ResTy,
                                         SmallVectorImpl<CanQualType> &ArgTys) {
   // 'this' is already in place
   // TODO: 'for base' flag

   if (Type == Dtor_Deleting) {
     // The scalar deleting destructor takes an implicit bool parameter.
     ArgTys.push_back(CGM.getContext().BoolTy);
   }
 }

 static bool IsDeletingDtor(GlobalDecl GD) {
   const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl());
   if (isa<CXXDestructorDecl>(MD)) {
     return GD.getDtorType() == Dtor_Deleting;
   }
   return false;
 }

 void MicrosoftCXXABI::BuildInstanceFunctionParams(CodeGenFunction &CGF,
                                                   QualType &ResTy,
                                                   FunctionArgList &Params) {
   BuildThisParam(CGF, Params);
   if (needThisReturn(CGF.CurGD)) {
     ResTy = Params[0]->getType();
   }

   ASTContext &Context = getContext();
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
   if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
     ImplicitParamDecl *IsMostDerived
       = ImplicitParamDecl::Create(Context, 0,
                                   CGF.CurGD.getDecl()->getLocation(),
                                   &Context.Idents.get("is_most_derived"),
                                   Context.IntTy);
     Params.push_back(IsMostDerived);
     getStructorImplicitParamDecl(CGF) = IsMostDerived;
   } else if (IsDeletingDtor(CGF.CurGD)) {
     ImplicitParamDecl *ShouldDelete
       = ImplicitParamDecl::Create(Context, 0,
                                   CGF.CurGD.getDecl()->getLocation(),
                                   &Context.Idents.get("should_call_delete"),
                                   Context.BoolTy);
     Params.push_back(ShouldDelete);
     getStructorImplicitParamDecl(CGF) = ShouldDelete;
   }
 }

 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
   EmitThisParam(CGF);
   if (needThisReturn(CGF.CurGD)) {
     CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
   }

   const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
   if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
     assert(getStructorImplicitParamDecl(CGF) &&
            "no implicit parameter for a constructor with virtual bases?");
     getStructorImplicitParamValue(CGF)
       = CGF.Builder.CreateLoad(
           CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
           "is_most_derived");
   }

   if (IsDeletingDtor(CGF.CurGD)) {
     assert(getStructorImplicitParamDecl(CGF) &&
            "no implicit parameter for a deleting destructor?");
     getStructorImplicitParamValue(CGF)
       = CGF.Builder.CreateLoad(
           CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
           "should_call_delete");
   }
 }

 llvm::Value *MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
                                           const CXXConstructorDecl *D,
                                           CXXCtorType Type, bool ForVirtualBase,
                                           bool Delegating,
                                           llvm::Value *This,
                                           CallExpr::const_arg_iterator ArgBeg,
                                           CallExpr::const_arg_iterator ArgEnd) {
   assert(Type == Ctor_Complete || Type == Ctor_Base);
   llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Ctor_Complete);

   llvm::Value *ImplicitParam = 0;
   QualType ImplicitParamTy;
   if (D->getParent()->getNumVBases()) {
     ImplicitParam = llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
     ImplicitParamTy = getContext().IntTy;
   }

   // FIXME: Provide a source location here.
   CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This,
                         ImplicitParam, ImplicitParamTy,
                         ArgBeg, ArgEnd);
   return Callee;
 }

 RValue MicrosoftCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF,
                                                   const CXXDestructorDecl *Dtor,
                                                   CXXDtorType DtorType,
                                                   SourceLocation CallLoc,
                                                   ReturnValueSlot ReturnValue,
                                                   llvm::Value *This) {
   assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);

   // We have only one destructor in the vftable but can get both behaviors
   // by passing an implicit bool parameter.
   const CGFunctionInfo *FInfo
       = &CGM.getTypes().arrangeCXXDestructor(Dtor, Dtor_Deleting);
   llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
   llvm::Value *Callee = CGF.BuildVirtualCall(Dtor, Dtor_Deleting, This, Ty);

   ASTContext &Context = CGF.getContext();
   llvm::Value *ImplicitParam
     = llvm::ConstantInt::get(llvm::IntegerType::getInt1Ty(CGF.getLLVMContext()),
                              DtorType == Dtor_Deleting);

   return CGF.EmitCXXMemberCall(Dtor, CallLoc, Callee, ReturnValue, This,
                                ImplicitParam, Context.BoolTy, 0, 0);
 }

 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
                                    QualType elementType) {
   // Microsoft seems to completely ignore the possibility of a
   // two-argument usual deallocation function.
   return elementType.isDestructedType();
 }

 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
   // Microsoft seems to completely ignore the possibility of a
   // two-argument usual deallocation function.
   return expr->getAllocatedType().isDestructedType();
 }

 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
   // The array cookie is always a size_t; we then pad that out to the
   // alignment of the element type.
   ASTContext &Ctx = getContext();
   return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
                   Ctx.getTypeAlignInChars(type));
 }

 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
                                                   llvm::Value *allocPtr,
                                                   CharUnits cookieSize) {
   unsigned AS = allocPtr->getType()->getPointerAddressSpace();
   llvm::Value *numElementsPtr =
     CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
   return CGF.Builder.CreateLoad(numElementsPtr);
 }

 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
                                                     llvm::Value *newPtr,
                                                     llvm::Value *numElements,
                                                     const CXXNewExpr *expr,
                                                     QualType elementType) {
   assert(requiresArrayCookie(expr));

   // The size of the cookie.
   CharUnits cookieSize = getArrayCookieSizeImpl(elementType);

   // Compute an offset to the cookie.
   llvm::Value *cookiePtr = newPtr;

   // Write the number of elements into the appropriate slot.
   unsigned AS = newPtr->getType()->getPointerAddressSpace();
   llvm::Value *numElementsPtr
     = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
   CGF.Builder.CreateStore(numElements, numElementsPtr);

   // Finally, compute a pointer to the actual data buffer by skipping
   // over the cookie completely.
   return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
                                                 cookieSize.getQuantity());
 }

 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
                                       llvm::GlobalVariable *DeclPtr,
                                       bool PerformInit) {
   // FIXME: this code was only tested for global initialization.
   // Not sure whether we want thread-safe static local variables as VS
   // doesn't make them thread-safe.

   // Emit the initializer and add a global destructor if appropriate.
   CGF.EmitCXXGlobalVarDeclInit(D, DeclPtr, PerformInit);
 }

 // Returns true for member pointer types that we know how to represent with a
 // simple ptrdiff_t.  Currently we only know how to emit, test, and load member
 // data pointers for complete single inheritance classes.
 static bool isSimpleMemberPointer(const MemberPointerType *MPT) {
   const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
   return (MPT->isMemberDataPointer() &&
           !MPT->getClass()->isIncompleteType() &&
           RD->getNumVBases() == 0);
 }

 llvm::Constant *
 MicrosoftCXXABI::getSimpleNullMemberPointer(const MemberPointerType *MPT) {
   if (isSimpleMemberPointer(MPT)) {
     const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
     // A null member data pointer is represented as -1 if the class is not
     // polymorphic, and 0 otherwise.
     if (RD->isPolymorphic())
       return getZeroPtrDiff();
     return getAllOnesPtrDiff();
   }
   return GetBogusMemberPointer(QualType(MPT, 0));
 }

 llvm::Constant *
 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
   if (isSimpleMemberPointer(MPT))
     return getSimpleNullMemberPointer(MPT);
   // FIXME: Implement function member pointers.
   return GetBogusMemberPointer(QualType(MPT, 0));
 }

 llvm::Constant *
 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
                                        CharUnits offset) {
   // Member data pointers are plain offsets when no virtual bases are involved.
   if (isSimpleMemberPointer(MPT))
     return llvm::ConstantInt::get(CGM.PtrDiffTy, offset.getQuantity());
   // FIXME: Implement member pointers other inheritance models.
   return GetBogusMemberPointer(QualType(MPT, 0));
 }

 llvm::Value *
 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
                                             llvm::Value *MemPtr,
                                             const MemberPointerType *MPT) {
   CGBuilderTy &Builder = CGF.Builder;

   // For member data pointers, this is just a check against -1 or 0.
   if (isSimpleMemberPointer(MPT)) {
     llvm::Constant *Val = getSimpleNullMemberPointer(MPT);
     return Builder.CreateICmpNE(MemPtr, Val, "memptr.tobool");
   }

   // FIXME: Implement member pointers other inheritance models.
   ErrorUnsupportedABI(CGF, "function member pointer tests");
   return GetBogusMemberPointer(QualType(MPT, 0));
 }

 llvm::Value *
 MicrosoftCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
                                               llvm::Value *Base,
                                               llvm::Value *MemPtr,
                                               const MemberPointerType *MPT) {
   unsigned AS = Base->getType()->getPointerAddressSpace();
   llvm::Type *PType =
       CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
   CGBuilderTy &Builder = CGF.Builder;

   if (MPT->isMemberFunctionPointer()) {
     ErrorUnsupportedABI(CGF, "function member pointer address");
     return llvm::Constant::getNullValue(PType);
   }

   llvm::Value *Addr;
   if (isSimpleMemberPointer(MPT)) {
     // Add the offset with GEP and i8*.
     assert(MemPtr->getType() == CGM.PtrDiffTy);
     Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
     Addr = Builder.CreateInBoundsGEP(Base, MemPtr, "memptr.offset");
   } else {
     ErrorUnsupportedABI(CGF, "non-scalar member pointers");
     return llvm::Constant::getNullValue(PType);
   }

   // Cast the address to the appropriate pointer type, adopting the address
   // space of the base pointer.
   return Builder.CreateBitCast(Addr, PType);
 }

 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
   return new MicrosoftCXXABI(CGM);
 }
	//===--- MicrosoftCXXABI.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 C++ code generation targeting the Microsoft Visual C++ ABI.
	// The class in this file generates structures that follow the Microsoft
	// Visual C++ ABI, which is actually not very well documented at all outside
	// of Microsoft.
	//
	//===----------------------------------------------------------------------===//

	#include "CGCXXABI.h"
	#include "CodeGenModule.h"
	#include "clang/AST/Decl.h"
	#include "clang/AST/DeclCXX.h"

	using namespace clang;
	using namespace CodeGen;

	namespace {

	class MicrosoftCXXABI : public CGCXXABI {
	public:
	MicrosoftCXXABI(CodeGenModule &CGM) : CGCXXABI(CGM) {}

	StringRef GetPureVirtualCallName() { return "_purecall"; }
	// No known support for deleted functions in MSVC yet, so this choice is
	// arbitrary.
	StringRef GetDeletedVirtualCallName() { return "_purecall"; }

	llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF,
	llvm::Value *ptr,
	QualType type);

	void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
	CXXCtorType Type,
	CanQualType &ResTy,
	SmallVectorImpl<CanQualType> &ArgTys);

	llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF);

	void BuildDestructorSignature(const CXXDestructorDecl *Ctor,
	CXXDtorType Type,
	CanQualType &ResTy,
	SmallVectorImpl<CanQualType> &ArgTys);

	void BuildInstanceFunctionParams(CodeGenFunction &CGF,
	QualType &ResTy,
	FunctionArgList &Params);

	void EmitInstanceFunctionProlog(CodeGenFunction &CGF);

	llvm::Value *EmitConstructorCall(CodeGenFunction &CGF,
	const CXXConstructorDecl *D,
	CXXCtorType Type, bool ForVirtualBase,
	bool Delegating,
	llvm::Value *This,
	CallExpr::const_arg_iterator ArgBeg,
	CallExpr::const_arg_iterator ArgEnd);

	RValue EmitVirtualDestructorCall(CodeGenFunction &CGF,
	const CXXDestructorDecl *Dtor,
	CXXDtorType DtorType,
	SourceLocation CallLoc,
	ReturnValueSlot ReturnValue,
	llvm::Value *This);

	void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
	llvm::GlobalVariable *DeclPtr,
	bool PerformInit);

	// ==== Notes on array cookies =========
	//
	// MSVC seems to only use cookies when the class has a destructor; a
	// two-argument usual array deallocation function isn't sufficient.
	//
	// For example, this code prints "100" and "1":
	// struct A {
	// char x;
	// void *operator new[](size_t sz) {
	// printf("%u\n", sz);
	// return malloc(sz);
	// }
	// void operator delete[](void *p, size_t sz) {
	// printf("%u\n", sz);
	// free(p);
	// }
	// };
	// int main() {
	// A *p = new A[100];
	// delete[] p;
	// }
	// Whereas it prints "104" and "104" if you give A a destructor.

	bool requiresArrayCookie(const CXXDeleteExpr *expr, QualType elementType);
	bool requiresArrayCookie(const CXXNewExpr *expr);
	CharUnits getArrayCookieSizeImpl(QualType type);
	llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
	llvm::Value *NewPtr,
	llvm::Value *NumElements,
	const CXXNewExpr *expr,
	QualType ElementType);
	llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
	llvm::Value *allocPtr,
	CharUnits cookieSize);
	static bool needThisReturn(GlobalDecl GD);

	private:
	llvm::Constant getSimpleNullMemberPointer(const MemberPointerType MPT);

	llvm::Constant *getZeroPtrDiff() {
	return llvm::ConstantInt::get(CGM.PtrDiffTy, 0);
	}

	llvm::Constant *getAllOnesPtrDiff() {
	return llvm::Constant::getAllOnesValue(CGM.PtrDiffTy);
	}

	public:
	virtual llvm::Constant EmitNullMemberPointer(const MemberPointerType MPT);

	virtual llvm::Constant EmitMemberDataPointer(const MemberPointerType MPT,
	CharUnits offset);

	virtual llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
	llvm::Value *MemPtr,
	const MemberPointerType *MPT);

	virtual llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
	llvm::Value *Base,
	llvm::Value *MemPtr,
	const MemberPointerType *MPT);

	};

	}

	llvm::Value *MicrosoftCXXABI::adjustToCompleteObject(CodeGenFunction &CGF,
	llvm::Value *ptr,
	QualType type) {
	// FIXME: implement
	return ptr;
	}

	bool MicrosoftCXXABI::needThisReturn(GlobalDecl GD) {
	const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl());
	return isa<CXXConstructorDecl>(MD);
	}

	void MicrosoftCXXABI::BuildConstructorSignature(const CXXConstructorDecl *Ctor,
	CXXCtorType Type,
	CanQualType &ResTy,
	SmallVectorImpl<CanQualType> &ArgTys) {
	// 'this' is already in place

	// Ctor returns this ptr
	ResTy = ArgTys[0];

	const CXXRecordDecl *Class = Ctor->getParent();
	if (Class->getNumVBases()) {
	// Constructors of classes with virtual bases take an implicit parameter.
	ArgTys.push_back(CGM.getContext().IntTy);
	}
	}

	llvm::BasicBlock *MicrosoftCXXABI::EmitCtorCompleteObjectHandler(
	CodeGenFunction &CGF) {
	llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
	assert(IsMostDerivedClass &&
	"ctor for a class with virtual bases must have an implicit parameter");
	llvm::Value *IsCompleteObject
	= CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");

	llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
	llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
	CGF.Builder.CreateCondBr(IsCompleteObject,
	CallVbaseCtorsBB, SkipVbaseCtorsBB);

	CGF.EmitBlock(CallVbaseCtorsBB);
	// FIXME: emit vbtables somewhere around here.

	// CGF will put the base ctor calls in this basic block for us later.

	return SkipVbaseCtorsBB;
	}

	void MicrosoftCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor,
	CXXDtorType Type,
	CanQualType &ResTy,
	SmallVectorImpl<CanQualType> &ArgTys) {
	// 'this' is already in place
	// TODO: 'for base' flag

	if (Type == Dtor_Deleting) {
	// The scalar deleting destructor takes an implicit bool parameter.
	ArgTys.push_back(CGM.getContext().BoolTy);
	}
	}

	static bool IsDeletingDtor(GlobalDecl GD) {
	const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl());
	if (isa<CXXDestructorDecl>(MD)) {
	return GD.getDtorType() == Dtor_Deleting;
	}
	return false;
	}

	void MicrosoftCXXABI::BuildInstanceFunctionParams(CodeGenFunction &CGF,
	QualType &ResTy,
	FunctionArgList &Params) {
	BuildThisParam(CGF, Params);
	if (needThisReturn(CGF.CurGD)) {
	ResTy = Params[0]->getType();
	}

	ASTContext &Context = getContext();
	const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
	if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
	ImplicitParamDecl *IsMostDerived
	= ImplicitParamDecl::Create(Context, 0,
	CGF.CurGD.getDecl()->getLocation(),
	&Context.Idents.get("is_most_derived"),
	Context.IntTy);
	Params.push_back(IsMostDerived);
	getStructorImplicitParamDecl(CGF) = IsMostDerived;
	} else if (IsDeletingDtor(CGF.CurGD)) {
	ImplicitParamDecl *ShouldDelete
	= ImplicitParamDecl::Create(Context, 0,
	CGF.CurGD.getDecl()->getLocation(),
	&Context.Idents.get("should_call_delete"),
	Context.BoolTy);
	Params.push_back(ShouldDelete);
	getStructorImplicitParamDecl(CGF) = ShouldDelete;
	}
	}

	void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
	EmitThisParam(CGF);
	if (needThisReturn(CGF.CurGD)) {
	CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
	}

	const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
	if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
	assert(getStructorImplicitParamDecl(CGF) &&
	"no implicit parameter for a constructor with virtual bases?");
	getStructorImplicitParamValue(CGF)
	= CGF.Builder.CreateLoad(
	CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
	"is_most_derived");
	}

	if (IsDeletingDtor(CGF.CurGD)) {
	assert(getStructorImplicitParamDecl(CGF) &&
	"no implicit parameter for a deleting destructor?");
	getStructorImplicitParamValue(CGF)
	= CGF.Builder.CreateLoad(
	CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
	"should_call_delete");
	}
	}

	llvm::Value *MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
	const CXXConstructorDecl *D,
	CXXCtorType Type, bool ForVirtualBase,
	bool Delegating,
	llvm::Value *This,
	CallExpr::const_arg_iterator ArgBeg,
	CallExpr::const_arg_iterator ArgEnd) {
	assert(Type == Ctor_Complete \|\| Type == Ctor_Base);
	llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Ctor_Complete);

	llvm::Value *ImplicitParam = 0;
	QualType ImplicitParamTy;
	if (D->getParent()->getNumVBases()) {
	ImplicitParam = llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
	ImplicitParamTy = getContext().IntTy;
	}

	// FIXME: Provide a source location here.
	CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This,
	ImplicitParam, ImplicitParamTy,
	ArgBeg, ArgEnd);
	return Callee;
	}

	RValue MicrosoftCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF,
	const CXXDestructorDecl *Dtor,
	CXXDtorType DtorType,
	SourceLocation CallLoc,
	ReturnValueSlot ReturnValue,
	llvm::Value *This) {
	assert(DtorType == Dtor_Deleting \|\| DtorType == Dtor_Complete);

	// We have only one destructor in the vftable but can get both behaviors
	// by passing an implicit bool parameter.
	const CGFunctionInfo *FInfo
	= &CGM.getTypes().arrangeCXXDestructor(Dtor, Dtor_Deleting);
	llvm::Type Ty = CGF.CGM.getTypes().GetFunctionType(FInfo);
	llvm::Value *Callee = CGF.BuildVirtualCall(Dtor, Dtor_Deleting, This, Ty);

	ASTContext &Context = CGF.getContext();
	llvm::Value *ImplicitParam
	= llvm::ConstantInt::get(llvm::IntegerType::getInt1Ty(CGF.getLLVMContext()),
	DtorType == Dtor_Deleting);

	return CGF.EmitCXXMemberCall(Dtor, CallLoc, Callee, ReturnValue, This,
	ImplicitParam, Context.BoolTy, 0, 0);
	}

	bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
	QualType elementType) {
	// Microsoft seems to completely ignore the possibility of a
	// two-argument usual deallocation function.
	return elementType.isDestructedType();
	}

	bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
	// Microsoft seems to completely ignore the possibility of a
	// two-argument usual deallocation function.
	return expr->getAllocatedType().isDestructedType();
	}

	CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
	// The array cookie is always a size_t; we then pad that out to the
	// alignment of the element type.
	ASTContext &Ctx = getContext();
	return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
	Ctx.getTypeAlignInChars(type));
	}

	llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
	llvm::Value *allocPtr,
	CharUnits cookieSize) {
	unsigned AS = allocPtr->getType()->getPointerAddressSpace();
	llvm::Value *numElementsPtr =
	CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
	return CGF.Builder.CreateLoad(numElementsPtr);
	}

	llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
	llvm::Value *newPtr,
	llvm::Value *numElements,
	const CXXNewExpr *expr,
	QualType elementType) {
	assert(requiresArrayCookie(expr));

	// The size of the cookie.
	CharUnits cookieSize = getArrayCookieSizeImpl(elementType);

	// Compute an offset to the cookie.
	llvm::Value *cookiePtr = newPtr;

	// Write the number of elements into the appropriate slot.
	unsigned AS = newPtr->getType()->getPointerAddressSpace();
	llvm::Value *numElementsPtr
	= CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
	CGF.Builder.CreateStore(numElements, numElementsPtr);

	// Finally, compute a pointer to the actual data buffer by skipping
	// over the cookie completely.
	return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
	cookieSize.getQuantity());
	}

	void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
	llvm::GlobalVariable *DeclPtr,
	bool PerformInit) {
	// FIXME: this code was only tested for global initialization.
	// Not sure whether we want thread-safe static local variables as VS
	// doesn't make them thread-safe.

	// Emit the initializer and add a global destructor if appropriate.
	CGF.EmitCXXGlobalVarDeclInit(D, DeclPtr, PerformInit);
	}

	// Returns true for member pointer types that we know how to represent with a
	// simple ptrdiff_t. Currently we only know how to emit, test, and load member
	// data pointers for complete single inheritance classes.
	static bool isSimpleMemberPointer(const MemberPointerType *MPT) {
	const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
	return (MPT->isMemberDataPointer() &&
	!MPT->getClass()->isIncompleteType() &&
	RD->getNumVBases() == 0);
	}

	llvm::Constant *
	MicrosoftCXXABI::getSimpleNullMemberPointer(const MemberPointerType *MPT) {
	if (isSimpleMemberPointer(MPT)) {
	const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
	// A null member data pointer is represented as -1 if the class is not
	// polymorphic, and 0 otherwise.
	if (RD->isPolymorphic())
	return getZeroPtrDiff();
	return getAllOnesPtrDiff();
	}
	return GetBogusMemberPointer(QualType(MPT, 0));
	}

	llvm::Constant *
	MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
	if (isSimpleMemberPointer(MPT))
	return getSimpleNullMemberPointer(MPT);
	// FIXME: Implement function member pointers.
	return GetBogusMemberPointer(QualType(MPT, 0));
	}

	llvm::Constant *
	MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
	CharUnits offset) {
	// Member data pointers are plain offsets when no virtual bases are involved.
	if (isSimpleMemberPointer(MPT))
	return llvm::ConstantInt::get(CGM.PtrDiffTy, offset.getQuantity());
	// FIXME: Implement member pointers other inheritance models.
	return GetBogusMemberPointer(QualType(MPT, 0));
	}

	llvm::Value *
	MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
	llvm::Value *MemPtr,
	const MemberPointerType *MPT) {
	CGBuilderTy &Builder = CGF.Builder;

	// For member data pointers, this is just a check against -1 or 0.
	if (isSimpleMemberPointer(MPT)) {
	llvm::Constant *Val = getSimpleNullMemberPointer(MPT);
	return Builder.CreateICmpNE(MemPtr, Val, "memptr.tobool");
	}

	// FIXME: Implement member pointers other inheritance models.
	ErrorUnsupportedABI(CGF, "function member pointer tests");
	return GetBogusMemberPointer(QualType(MPT, 0));
	}

	llvm::Value *
	MicrosoftCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
	llvm::Value *Base,
	llvm::Value *MemPtr,
	const MemberPointerType *MPT) {
	unsigned AS = Base->getType()->getPointerAddressSpace();
	llvm::Type *PType =
	CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
	CGBuilderTy &Builder = CGF.Builder;

	if (MPT->isMemberFunctionPointer()) {
	ErrorUnsupportedABI(CGF, "function member pointer address");
	return llvm::Constant::getNullValue(PType);
	}

	llvm::Value *Addr;
	if (isSimpleMemberPointer(MPT)) {
	// Add the offset with GEP and i8*.
	assert(MemPtr->getType() == CGM.PtrDiffTy);
	Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
	Addr = Builder.CreateInBoundsGEP(Base, MemPtr, "memptr.offset");
	} else {
	ErrorUnsupportedABI(CGF, "non-scalar member pointers");
	return llvm::Constant::getNullValue(PType);
	}

	// Cast the address to the appropriate pointer type, adopting the address
	// space of the base pointer.
	return Builder.CreateBitCast(Addr, PType);
	}

	CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
	return new MicrosoftCXXABI(CGM);
	}