1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr), HandlerMapEntryType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
88 getAddrOfCXXHandlerMapEntry(QualType Ty, QualType CatchHandlerType) override;
90 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
91 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
92 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
94 llvm::Type *StdTypeInfoPtrTy) override;
96 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
97 QualType SrcRecordTy) override;
99 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
100 QualType SrcRecordTy, QualType DestTy,
101 QualType DestRecordTy,
102 llvm::BasicBlock *CastEnd) override;
104 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
105 QualType SrcRecordTy,
106 QualType DestTy) override;
108 bool EmitBadCastCall(CodeGenFunction &CGF) override;
111 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
112 const CXXRecordDecl *ClassDecl,
113 const CXXRecordDecl *BaseClassDecl) override;
116 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
117 const CXXRecordDecl *RD) override;
119 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
120 const CXXRecordDecl *RD) override;
122 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
124 // Background on MSVC destructors
125 // ==============================
127 // Both Itanium and MSVC ABIs have destructor variants. The variant names
128 // roughly correspond in the following way:
130 // Base -> no name, just ~Class
131 // Complete -> vbase destructor
132 // Deleting -> scalar deleting destructor
133 // vector deleting destructor
135 // The base and complete destructors are the same as in Itanium, although the
136 // complete destructor does not accept a VTT parameter when there are virtual
137 // bases. A separate mechanism involving vtordisps is used to ensure that
138 // virtual methods of destroyed subobjects are not called.
140 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
141 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
142 // pointer points to an array. The scalar deleting destructor assumes that
143 // bit 2 is zero, and therefore does not contain a loop.
145 // For virtual destructors, only one entry is reserved in the vftable, and it
146 // always points to the vector deleting destructor. The vector deleting
147 // destructor is the most general, so it can be used to destroy objects in
148 // place, delete single heap objects, or delete arrays.
150 // A TU defining a non-inline destructor is only guaranteed to emit a base
151 // destructor, and all of the other variants are emitted on an as-needed basis
152 // in COMDATs. Because a non-base destructor can be emitted in a TU that
153 // lacks a definition for the destructor, non-base destructors must always
154 // delegate to or alias the base destructor.
156 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
157 SmallVectorImpl<CanQualType> &ArgTys) override;
159 /// Non-base dtors should be emitted as delegating thunks in this ABI.
160 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
161 CXXDtorType DT) const override {
162 return DT != Dtor_Base;
165 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
167 const CXXRecordDecl *
168 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
169 MD = MD->getCanonicalDecl();
170 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
171 MicrosoftVTableContext::MethodVFTableLocation ML =
172 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
173 // The vbases might be ordered differently in the final overrider object
174 // and the complete object, so the "this" argument may sometimes point to
175 // memory that has no particular type (e.g. past the complete object).
176 // In this case, we just use a generic pointer type.
177 // FIXME: might want to have a more precise type in the non-virtual
178 // multiple inheritance case.
179 if (ML.VBase || !ML.VFPtrOffset.isZero())
182 return MD->getParent();
186 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
188 bool VirtualCall) override;
190 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
191 FunctionArgList &Params) override;
193 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
194 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
196 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
198 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
199 const CXXConstructorDecl *D,
200 CXXCtorType Type, bool ForVirtualBase,
202 CallArgList &Args) override;
204 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
205 CXXDtorType Type, bool ForVirtualBase,
206 bool Delegating, llvm::Value *This) override;
208 void emitVTableDefinitions(CodeGenVTables &CGVT,
209 const CXXRecordDecl *RD) override;
211 llvm::Value *getVTableAddressPointInStructor(
212 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
213 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
214 bool &NeedsVirtualOffset) override;
217 getVTableAddressPointForConstExpr(BaseSubobject Base,
218 const CXXRecordDecl *VTableClass) override;
220 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
221 CharUnits VPtrOffset) override;
223 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
225 llvm::Type *Ty) override;
227 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
228 const CXXDestructorDecl *Dtor,
229 CXXDtorType DtorType,
231 const CXXMemberCallExpr *CE) override;
233 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
234 CallArgList &CallArgs) override {
235 assert(GD.getDtorType() == Dtor_Deleting &&
236 "Only deleting destructor thunks are available in this ABI");
237 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
241 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
243 llvm::GlobalVariable *
244 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
245 llvm::GlobalVariable::LinkageTypes Linkage);
247 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
248 llvm::GlobalVariable *GV) const;
250 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
251 GlobalDecl GD, bool ReturnAdjustment) override {
252 // Never dllimport/dllexport thunks.
253 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
256 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
258 if (Linkage == GVA_Internal)
259 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
260 else if (ReturnAdjustment)
261 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
263 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
266 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
267 const ThisAdjustment &TA) override;
269 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
270 const ReturnAdjustment &RA) override;
272 void EmitThreadLocalInitFuncs(
274 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
276 ArrayRef<llvm::Function *> CXXThreadLocalInits,
277 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
279 bool usesThreadWrapperFunction() const override { return false; }
280 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
281 QualType LValType) override;
283 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
284 llvm::GlobalVariable *DeclPtr,
285 bool PerformInit) override;
286 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
287 llvm::Constant *Dtor, llvm::Constant *Addr) override;
289 // ==== Notes on array cookies =========
291 // MSVC seems to only use cookies when the class has a destructor; a
292 // two-argument usual array deallocation function isn't sufficient.
294 // For example, this code prints "100" and "1":
297 // void *operator new[](size_t sz) {
298 // printf("%u\n", sz);
299 // return malloc(sz);
301 // void operator delete[](void *p, size_t sz) {
302 // printf("%u\n", sz);
307 // A *p = new A[100];
310 // Whereas it prints "104" and "104" if you give A a destructor.
312 bool requiresArrayCookie(const CXXDeleteExpr *expr,
313 QualType elementType) override;
314 bool requiresArrayCookie(const CXXNewExpr *expr) override;
315 CharUnits getArrayCookieSizeImpl(QualType type) override;
316 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
318 llvm::Value *NumElements,
319 const CXXNewExpr *expr,
320 QualType ElementType) override;
321 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
322 llvm::Value *allocPtr,
323 CharUnits cookieSize) override;
325 friend struct MSRTTIBuilder;
327 bool isImageRelative() const {
328 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
331 // 5 routines for constructing the llvm types for MS RTTI structs.
332 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
333 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
334 TDTypeName += llvm::utostr(TypeInfoString.size());
335 llvm::StructType *&TypeDescriptorType =
336 TypeDescriptorTypeMap[TypeInfoString.size()];
337 if (TypeDescriptorType)
338 return TypeDescriptorType;
339 llvm::Type *FieldTypes[] = {
342 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
344 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
345 return TypeDescriptorType;
348 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
349 if (!isImageRelative())
354 llvm::StructType *getBaseClassDescriptorType() {
355 if (BaseClassDescriptorType)
356 return BaseClassDescriptorType;
357 llvm::Type *FieldTypes[] = {
358 getImageRelativeType(CGM.Int8PtrTy),
364 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
366 BaseClassDescriptorType = llvm::StructType::create(
367 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
368 return BaseClassDescriptorType;
371 llvm::StructType *getClassHierarchyDescriptorType() {
372 if (ClassHierarchyDescriptorType)
373 return ClassHierarchyDescriptorType;
374 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
375 ClassHierarchyDescriptorType = llvm::StructType::create(
376 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
377 llvm::Type *FieldTypes[] = {
381 getImageRelativeType(
382 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
384 ClassHierarchyDescriptorType->setBody(FieldTypes);
385 return ClassHierarchyDescriptorType;
388 llvm::StructType *getCompleteObjectLocatorType() {
389 if (CompleteObjectLocatorType)
390 return CompleteObjectLocatorType;
391 CompleteObjectLocatorType = llvm::StructType::create(
392 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
393 llvm::Type *FieldTypes[] = {
397 getImageRelativeType(CGM.Int8PtrTy),
398 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
399 getImageRelativeType(CompleteObjectLocatorType),
401 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
402 if (!isImageRelative())
403 FieldTypesRef = FieldTypesRef.drop_back();
404 CompleteObjectLocatorType->setBody(FieldTypesRef);
405 return CompleteObjectLocatorType;
408 llvm::GlobalVariable *getImageBase() {
409 StringRef Name = "__ImageBase";
410 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
413 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
415 llvm::GlobalValue::ExternalLinkage,
416 /*Initializer=*/nullptr, Name);
419 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
420 if (!isImageRelative())
423 if (PtrVal->isNullValue())
424 return llvm::Constant::getNullValue(CGM.IntTy);
426 llvm::Constant *ImageBaseAsInt =
427 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
428 llvm::Constant *PtrValAsInt =
429 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
430 llvm::Constant *Diff =
431 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
432 /*HasNUW=*/true, /*HasNSW=*/true);
433 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
437 MicrosoftMangleContext &getMangleContext() {
438 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
441 llvm::Constant *getZeroInt() {
442 return llvm::ConstantInt::get(CGM.IntTy, 0);
445 llvm::Constant *getAllOnesInt() {
446 return llvm::Constant::getAllOnesValue(CGM.IntTy);
449 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
450 return C ? C : getZeroInt();
453 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
454 return C ? C : getZeroInt();
457 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
460 GetNullMemberPointerFields(const MemberPointerType *MPT,
461 llvm::SmallVectorImpl<llvm::Constant *> &fields);
463 /// \brief Shared code for virtual base adjustment. Returns the offset from
464 /// the vbptr to the virtual base. Optionally returns the address of the
466 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
468 llvm::Value *VBPtrOffset,
469 llvm::Value *VBTableOffset,
470 llvm::Value **VBPtr = nullptr);
472 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
475 int32_t VBTableOffset,
476 llvm::Value **VBPtr = nullptr) {
477 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
478 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
479 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
480 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
483 std::pair<llvm::Value *, llvm::Value *>
484 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
485 QualType SrcRecordTy);
487 /// \brief Performs a full virtual base adjustment. Used to dereference
488 /// pointers to members of virtual bases.
489 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
490 const CXXRecordDecl *RD, llvm::Value *Base,
491 llvm::Value *VirtualBaseAdjustmentOffset,
492 llvm::Value *VBPtrOffset /* optional */);
494 /// \brief Emits a full member pointer with the fields common to data and
495 /// function member pointers.
496 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
497 bool IsMemberFunction,
498 const CXXRecordDecl *RD,
499 CharUnits NonVirtualBaseAdjustment);
501 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
502 const CXXMethodDecl *MD,
503 CharUnits NonVirtualBaseAdjustment);
505 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
508 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
509 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
511 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
512 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
514 /// \brief Generate a thunk for calling a virtual member function MD.
515 llvm::Function *EmitVirtualMemPtrThunk(
516 const CXXMethodDecl *MD,
517 const MicrosoftVTableContext::MethodVFTableLocation &ML);
520 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
522 bool isZeroInitializable(const MemberPointerType *MPT) override;
524 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
525 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
526 return RD->hasAttr<MSInheritanceAttr>();
529 bool isTypeInfoCalculable(QualType Ty) const override {
530 if (!CGCXXABI::isTypeInfoCalculable(Ty))
532 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
533 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
534 if (!RD->hasAttr<MSInheritanceAttr>())
540 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
542 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
543 CharUnits offset) override;
544 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
545 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
547 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
550 const MemberPointerType *MPT,
551 bool Inequality) override;
553 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
555 const MemberPointerType *MPT) override;
558 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
559 llvm::Value *Base, llvm::Value *MemPtr,
560 const MemberPointerType *MPT) override;
562 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
564 llvm::Value *Src) override;
566 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
567 llvm::Constant *Src) override;
570 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
571 llvm::Value *&This, llvm::Value *MemPtr,
572 const MemberPointerType *MPT) override;
574 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
576 llvm::StructType *getHandlerMapEntryType() {
577 if (!HandlerMapEntryType) {
578 llvm::Type *FieldTypes[] = {
580 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
582 HandlerMapEntryType = llvm::StructType::create(
583 CGM.getLLVMContext(), FieldTypes, "eh.HandlerMapEntry");
585 return HandlerMapEntryType;
588 llvm::StructType *getCatchableTypeType() {
589 if (CatchableTypeType)
590 return CatchableTypeType;
591 llvm::Type *FieldTypes[] = {
593 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
594 CGM.IntTy, // NonVirtualAdjustment
595 CGM.IntTy, // OffsetToVBPtr
596 CGM.IntTy, // VBTableIndex
598 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
600 CatchableTypeType = llvm::StructType::create(
601 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
602 return CatchableTypeType;
605 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
606 llvm::StructType *&CatchableTypeArrayType =
607 CatchableTypeArrayTypeMap[NumEntries];
608 if (CatchableTypeArrayType)
609 return CatchableTypeArrayType;
611 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
612 CTATypeName += llvm::utostr(NumEntries);
614 getImageRelativeType(getCatchableTypeType()->getPointerTo());
615 llvm::Type *FieldTypes[] = {
616 CGM.IntTy, // NumEntries
617 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
619 CatchableTypeArrayType =
620 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
621 return CatchableTypeArrayType;
624 llvm::StructType *getThrowInfoType() {
626 return ThrowInfoType;
627 llvm::Type *FieldTypes[] = {
629 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
630 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
631 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
633 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
635 return ThrowInfoType;
638 llvm::Constant *getThrowFn() {
639 // _CxxThrowException is passed an exception object and a ThrowInfo object
640 // which describes the exception.
641 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
642 llvm::FunctionType *FTy =
643 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
644 auto *Fn = cast<llvm::Function>(
645 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
646 // _CxxThrowException is stdcall on 32-bit x86 platforms.
647 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
648 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
652 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
655 llvm::Constant *getCatchableType(QualType T,
656 uint32_t NVOffset = 0,
657 int32_t VBPtrOffset = -1,
658 uint32_t VBIndex = 0);
660 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
662 llvm::GlobalVariable *getThrowInfo(QualType T) override;
665 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
666 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
667 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
668 /// \brief All the vftables that have been referenced.
669 VFTablesMapTy VFTablesMap;
670 VTablesMapTy VTablesMap;
672 /// \brief This set holds the record decls we've deferred vtable emission for.
673 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
676 /// \brief All the vbtables which have been referenced.
677 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
679 /// Info on the global variable used to guard initialization of static locals.
680 /// The BitIndex field is only used for externally invisible declarations.
682 GuardInfo() : Guard(nullptr), BitIndex(0) {}
683 llvm::GlobalVariable *Guard;
687 /// Map from DeclContext to the current guard variable. We assume that the
688 /// AST is visited in source code order.
689 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
691 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
692 llvm::StructType *BaseClassDescriptorType;
693 llvm::StructType *ClassHierarchyDescriptorType;
694 llvm::StructType *CompleteObjectLocatorType;
696 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
698 llvm::StructType *CatchableTypeType;
699 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
700 llvm::StructType *ThrowInfoType;
701 llvm::StructType *HandlerMapEntryType;
706 CGCXXABI::RecordArgABI
707 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
708 switch (CGM.getTarget().getTriple().getArch()) {
710 // FIXME: Implement for other architectures.
713 case llvm::Triple::x86:
714 // All record arguments are passed in memory on x86. Decide whether to
715 // construct the object directly in argument memory, or to construct the
716 // argument elsewhere and copy the bytes during the call.
718 // If C++ prohibits us from making a copy, construct the arguments directly
719 // into argument memory.
720 if (!canCopyArgument(RD))
721 return RAA_DirectInMemory;
723 // Otherwise, construct the argument into a temporary and copy the bytes
724 // into the outgoing argument memory.
727 case llvm::Triple::x86_64:
728 // Win64 passes objects with non-trivial copy ctors indirectly.
729 if (RD->hasNonTrivialCopyConstructor())
732 // If an object has a destructor, we'd really like to pass it indirectly
733 // because it allows us to elide copies. Unfortunately, MSVC makes that
734 // impossible for small types, which it will pass in a single register or
735 // stack slot. Most objects with dtors are large-ish, so handle that early.
736 // We can't call out all large objects as being indirect because there are
737 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
738 // how we pass large POD types.
739 if (RD->hasNonTrivialDestructor() &&
740 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
743 // We have a trivial copy constructor or no copy constructors, but we have
744 // to make sure it isn't deleted.
745 bool CopyDeleted = false;
746 for (const CXXConstructorDecl *CD : RD->ctors()) {
747 if (CD->isCopyConstructor()) {
748 assert(CD->isTrivial());
749 // We had at least one undeleted trivial copy ctor. Return directly.
750 if (!CD->isDeleted())
756 // The trivial copy constructor was deleted. Return indirectly.
760 // There were no copy ctors. Return in RAX.
764 llvm_unreachable("invalid enum");
767 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
768 const CXXDeleteExpr *DE,
770 QualType ElementType,
771 const CXXDestructorDecl *Dtor) {
772 // FIXME: Provide a source location here even though there's no
773 // CXXMemberCallExpr for dtor call.
774 bool UseGlobalDelete = DE->isGlobalDelete();
775 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
776 llvm::Value *MDThis =
777 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
779 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
782 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
783 llvm::Value *Args[] = {
784 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
785 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
786 auto *Fn = getThrowFn();
788 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
790 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
794 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
795 CallEndCatchMSVC() {}
796 void Emit(CodeGenFunction &CGF, Flags flags) override {
797 CGF.EmitNounwindRuntimeCall(
798 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
803 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
804 const CXXCatchStmt *S) {
805 // In the MS ABI, the runtime handles the copy, and the catch handler is
806 // responsible for destruction.
807 VarDecl *CatchParam = S->getExceptionDecl();
808 llvm::Value *Exn = CGF.getExceptionFromSlot();
809 llvm::Function *BeginCatch =
810 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
813 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
814 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
815 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
819 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
820 llvm::Value *ParamAddr =
821 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
822 llvm::Value *Args[2] = {Exn, ParamAddr};
823 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
824 // FIXME: Do we really need exceptional endcatch cleanups?
825 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
826 CGF.EmitAutoVarCleanups(var);
829 std::pair<llvm::Value *, llvm::Value *>
830 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
831 QualType SrcRecordTy) {
832 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
833 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
834 const ASTContext &Context = getContext();
836 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
837 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
839 // Perform a base adjustment.
840 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
841 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
842 [&](const CXXBaseSpecifier &Base) {
843 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
844 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
846 llvm::Value *Offset = GetVirtualBaseClassOffset(
847 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
848 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
849 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
850 return std::make_pair(Value, Offset);
853 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
854 QualType SrcRecordTy) {
855 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
857 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
860 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
861 llvm::Value *Argument) {
862 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
863 llvm::FunctionType *FTy =
864 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
865 llvm::Value *Args[] = {Argument};
866 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
867 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
870 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
871 llvm::CallSite Call =
872 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
873 Call.setDoesNotReturn();
874 CGF.Builder.CreateUnreachable();
877 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
878 QualType SrcRecordTy,
879 llvm::Value *ThisPtr,
880 llvm::Type *StdTypeInfoPtrTy) {
882 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
883 return CGF.Builder.CreateBitCast(
884 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
887 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
888 QualType SrcRecordTy) {
889 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
891 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
894 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
895 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
896 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
897 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
899 llvm::Value *SrcRTTI =
900 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
901 llvm::Value *DestRTTI =
902 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
905 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
907 // PVOID __RTDynamicCast(
913 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
914 CGF.Int8PtrTy, CGF.Int32Ty};
915 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
916 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
918 llvm::Value *Args[] = {
919 Value, Offset, SrcRTTI, DestRTTI,
920 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
921 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
922 return CGF.Builder.CreateBitCast(Value, DestLTy);
926 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
927 QualType SrcRecordTy,
930 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
932 // PVOID __RTCastToVoid(
934 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
935 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
936 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
938 llvm::Value *Args[] = {Value};
939 return CGF.EmitRuntimeCall(Function, Args);
942 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
946 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
947 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
948 const CXXRecordDecl *BaseClassDecl) {
949 const ASTContext &Context = getContext();
951 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
952 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
953 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
954 CharUnits VBTableChars =
956 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
957 llvm::Value *VBTableOffset =
958 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
960 llvm::Value *VBPtrToNewBase =
961 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
963 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
964 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
967 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
968 return isa<CXXConstructorDecl>(GD.getDecl());
971 static bool isDeletingDtor(GlobalDecl GD) {
972 return isa<CXXDestructorDecl>(GD.getDecl()) &&
973 GD.getDtorType() == Dtor_Deleting;
976 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
977 return isDeletingDtor(GD);
980 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
981 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
985 if (FI.isInstanceMethod()) {
986 // If it's an instance method, aggregates are always returned indirectly via
987 // the second parameter.
988 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
989 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
991 } else if (!RD->isPOD()) {
992 // If it's a free function, non-POD types are returned indirectly.
993 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
997 // Otherwise, use the C ABI rules.
1002 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1003 const CXXRecordDecl *RD) {
1004 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1005 assert(IsMostDerivedClass &&
1006 "ctor for a class with virtual bases must have an implicit parameter");
1007 llvm::Value *IsCompleteObject =
1008 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1010 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1011 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1012 CGF.Builder.CreateCondBr(IsCompleteObject,
1013 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1015 CGF.EmitBlock(CallVbaseCtorsBB);
1017 // Fill in the vbtable pointers here.
1018 EmitVBPtrStores(CGF, RD);
1020 // CGF will put the base ctor calls in this basic block for us later.
1022 return SkipVbaseCtorsBB;
1025 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1026 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1027 // In most cases, an override for a vbase virtual method can adjust
1028 // the "this" parameter by applying a constant offset.
1029 // However, this is not enough while a constructor or a destructor of some
1030 // class X is being executed if all the following conditions are met:
1031 // - X has virtual bases, (1)
1032 // - X overrides a virtual method M of a vbase Y, (2)
1033 // - X itself is a vbase of the most derived class.
1035 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1036 // which holds the extra amount of "this" adjustment we must do when we use
1037 // the X vftables (i.e. during X ctor or dtor).
1038 // Outside the ctors and dtors, the values of vtorDisps are zero.
1040 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1041 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1042 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1043 CGBuilderTy &Builder = CGF.Builder;
1046 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1047 llvm::Value *Int8This = nullptr; // Initialize lazily.
1049 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1051 if (!I->second.hasVtorDisp())
1054 llvm::Value *VBaseOffset =
1055 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1056 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1057 // just to Trunc back immediately.
1058 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1059 uint64_t ConstantVBaseOffset =
1060 Layout.getVBaseClassOffset(I->first).getQuantity();
1062 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1063 llvm::Value *VtorDispValue = Builder.CreateSub(
1064 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1068 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1069 CGF.Int8Ty->getPointerTo(AS));
1070 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1071 // vtorDisp is always the 32-bits before the vbase in the class layout.
1072 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1073 VtorDispPtr = Builder.CreateBitCast(
1074 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1076 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1080 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1081 const CXXMethodDecl *MD) {
1082 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1083 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1084 CallingConv ActualCallingConv =
1085 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1086 return ExpectedCallingConv == ActualCallingConv;
1089 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1090 // There's only one constructor type in this ABI.
1091 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1093 // Exported default constructors either have a simple call-site where they use
1094 // the typical calling convention and have a single 'this' pointer for an
1095 // argument -or- they get a wrapper function which appropriately thunks to the
1096 // real default constructor. This thunk is the default constructor closure.
1097 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1098 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1099 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1100 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1101 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1105 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1106 const CXXRecordDecl *RD) {
1107 llvm::Value *ThisInt8Ptr =
1108 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1109 const ASTContext &Context = getContext();
1110 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1112 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1113 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1114 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1115 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1116 const ASTRecordLayout &SubobjectLayout =
1117 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1118 CharUnits Offs = VBT->NonVirtualOffset;
1119 Offs += SubobjectLayout.getVBPtrOffset();
1120 if (VBT->getVBaseWithVPtr())
1121 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1122 llvm::Value *VBPtr =
1123 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1124 llvm::Value *GVPtr = CGF.Builder.CreateConstInBoundsGEP2_32(GV, 0, 0);
1125 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1126 "vbptr." + VBT->ReusingBase->getName());
1127 CGF.Builder.CreateStore(GVPtr, VBPtr);
1132 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1133 SmallVectorImpl<CanQualType> &ArgTys) {
1134 // TODO: 'for base' flag
1135 if (T == StructorType::Deleting) {
1136 // The scalar deleting destructor takes an implicit int parameter.
1137 ArgTys.push_back(getContext().IntTy);
1139 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1143 // All parameters are already in place except is_most_derived, which goes
1144 // after 'this' if it's variadic and last if it's not.
1146 const CXXRecordDecl *Class = CD->getParent();
1147 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1148 if (Class->getNumVBases()) {
1149 if (FPT->isVariadic())
1150 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1152 ArgTys.push_back(getContext().IntTy);
1156 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1157 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1158 // other destructor variants are delegating thunks.
1159 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1163 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1164 GD = GD.getCanonicalDecl();
1165 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1167 GlobalDecl LookupGD = GD;
1168 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1169 // Complete destructors take a pointer to the complete object as a
1170 // parameter, thus don't need this adjustment.
1171 if (GD.getDtorType() == Dtor_Complete)
1174 // There's no Dtor_Base in vftable but it shares the this adjustment with
1175 // the deleting one, so look it up instead.
1176 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1179 MicrosoftVTableContext::MethodVFTableLocation ML =
1180 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1181 CharUnits Adjustment = ML.VFPtrOffset;
1183 // Normal virtual instance methods need to adjust from the vfptr that first
1184 // defined the virtual method to the virtual base subobject, but destructors
1185 // do not. The vector deleting destructor thunk applies this adjustment for
1187 if (isa<CXXDestructorDecl>(MD))
1188 Adjustment = CharUnits::Zero();
1191 const ASTRecordLayout &DerivedLayout =
1192 getContext().getASTRecordLayout(MD->getParent());
1193 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1199 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1200 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1202 // If the call of a virtual function is not virtual, we just have to
1203 // compensate for the adjustment the virtual function does in its prologue.
1204 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1205 if (Adjustment.isZero())
1208 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1209 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1210 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1211 assert(Adjustment.isPositive());
1212 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1215 GD = GD.getCanonicalDecl();
1216 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1218 GlobalDecl LookupGD = GD;
1219 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1220 // Complete dtors take a pointer to the complete object,
1221 // thus don't need adjustment.
1222 if (GD.getDtorType() == Dtor_Complete)
1225 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1226 // with the base one, so look up the deleting one instead.
1227 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1229 MicrosoftVTableContext::MethodVFTableLocation ML =
1230 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1232 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1233 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1234 CharUnits StaticOffset = ML.VFPtrOffset;
1236 // Base destructors expect 'this' to point to the beginning of the base
1237 // subobject, not the first vfptr that happens to contain the virtual dtor.
1238 // However, we still need to apply the virtual base adjustment.
1239 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1240 StaticOffset = CharUnits::Zero();
1243 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1244 llvm::Value *VBaseOffset =
1245 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1246 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1248 if (!StaticOffset.isZero()) {
1249 assert(StaticOffset.isPositive());
1250 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1252 // Non-virtual adjustment might result in a pointer outside the allocated
1253 // object, e.g. if the final overrider class is laid out after the virtual
1254 // base that declares a method in the most derived class.
1255 // FIXME: Update the code that emits this adjustment in thunks prologues.
1256 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1258 This = CGF.Builder.CreateConstInBoundsGEP1_32(This,
1259 StaticOffset.getQuantity());
1265 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1267 FunctionArgList &Params) {
1268 ASTContext &Context = getContext();
1269 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1270 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1271 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1272 ImplicitParamDecl *IsMostDerived
1273 = ImplicitParamDecl::Create(Context, nullptr,
1274 CGF.CurGD.getDecl()->getLocation(),
1275 &Context.Idents.get("is_most_derived"),
1277 // The 'most_derived' parameter goes second if the ctor is variadic and last
1278 // if it's not. Dtors can't be variadic.
1279 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1280 if (FPT->isVariadic())
1281 Params.insert(Params.begin() + 1, IsMostDerived);
1283 Params.push_back(IsMostDerived);
1284 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1285 } else if (isDeletingDtor(CGF.CurGD)) {
1286 ImplicitParamDecl *ShouldDelete
1287 = ImplicitParamDecl::Create(Context, nullptr,
1288 CGF.CurGD.getDecl()->getLocation(),
1289 &Context.Idents.get("should_call_delete"),
1291 Params.push_back(ShouldDelete);
1292 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1296 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1297 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1298 // In this ABI, every virtual function takes a pointer to one of the
1299 // subobjects that first defines it as the 'this' parameter, rather than a
1300 // pointer to the final overrider subobject. Thus, we need to adjust it back
1301 // to the final overrider subobject before use.
1302 // See comments in the MicrosoftVFTableContext implementation for the details.
1303 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1304 if (Adjustment.isZero())
1307 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1308 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1309 *thisTy = This->getType();
1311 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1312 assert(Adjustment.isPositive());
1314 CGF.Builder.CreateConstInBoundsGEP1_32(This, -Adjustment.getQuantity());
1315 return CGF.Builder.CreateBitCast(This, thisTy);
1318 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1321 /// If this is a function that the ABI specifies returns 'this', initialize
1322 /// the return slot to 'this' at the start of the function.
1324 /// Unlike the setting of return types, this is done within the ABI
1325 /// implementation instead of by clients of CGCXXABI because:
1326 /// 1) getThisValue is currently protected
1327 /// 2) in theory, an ABI could implement 'this' returns some other way;
1328 /// HasThisReturn only specifies a contract, not the implementation
1329 if (HasThisReturn(CGF.CurGD))
1330 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1331 else if (hasMostDerivedReturn(CGF.CurGD))
1332 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1335 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1336 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1337 assert(getStructorImplicitParamDecl(CGF) &&
1338 "no implicit parameter for a constructor with virtual bases?");
1339 getStructorImplicitParamValue(CGF)
1340 = CGF.Builder.CreateLoad(
1341 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1345 if (isDeletingDtor(CGF.CurGD)) {
1346 assert(getStructorImplicitParamDecl(CGF) &&
1347 "no implicit parameter for a deleting destructor?");
1348 getStructorImplicitParamValue(CGF)
1349 = CGF.Builder.CreateLoad(
1350 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1351 "should_call_delete");
1355 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1356 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1357 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1358 assert(Type == Ctor_Complete || Type == Ctor_Base);
1360 // Check if we need a 'most_derived' parameter.
1361 if (!D->getParent()->getNumVBases())
1364 // Add the 'most_derived' argument second if we are variadic or last if not.
1365 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1366 llvm::Value *MostDerivedArg =
1367 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1368 RValue RV = RValue::get(MostDerivedArg);
1369 if (MostDerivedArg) {
1370 if (FPT->isVariadic())
1371 Args.insert(Args.begin() + 1,
1372 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1374 Args.add(RV, getContext().IntTy);
1377 return 1; // Added one arg.
1380 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1381 const CXXDestructorDecl *DD,
1382 CXXDtorType Type, bool ForVirtualBase,
1383 bool Delegating, llvm::Value *This) {
1384 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1386 if (DD->isVirtual()) {
1387 assert(Type != CXXDtorType::Dtor_Deleting &&
1388 "The deleting destructor should only be called via a virtual call");
1389 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1393 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1394 /*ImplicitParam=*/nullptr,
1395 /*ImplicitParamTy=*/QualType(), nullptr,
1396 getFromDtorType(Type));
1399 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1400 const CXXRecordDecl *RD) {
1401 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1402 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1404 for (VPtrInfo *Info : VFPtrs) {
1405 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1406 if (VTable->hasInitializer())
1409 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1410 ? getMSCompleteObjectLocator(RD, Info)
1413 const VTableLayout &VTLayout =
1414 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1415 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1416 RD, VTLayout.vtable_component_begin(),
1417 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1418 VTLayout.getNumVTableThunks(), RTTI);
1420 VTable->setInitializer(Init);
1424 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1425 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1426 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1427 NeedsVirtualOffset = (NearestVBase != nullptr);
1429 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1430 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1431 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1432 if (!VTableAddressPoint) {
1433 assert(Base.getBase()->getNumVBases() &&
1434 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1436 return VTableAddressPoint;
1439 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1440 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1441 SmallString<256> &Name) {
1442 llvm::raw_svector_ostream Out(Name);
1443 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1446 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1447 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1448 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1449 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1450 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1451 assert(VFTable && "Couldn't find a vftable for the given base?");
1455 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1456 CharUnits VPtrOffset) {
1457 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1458 // shouldn't be used in the given record type. We want to cache this result in
1459 // VFTablesMap, thus a simple zero check is not sufficient.
1460 VFTableIdTy ID(RD, VPtrOffset);
1461 VTablesMapTy::iterator I;
1463 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1467 llvm::GlobalVariable *&VTable = I->second;
1469 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1470 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1472 if (DeferredVFTables.insert(RD).second) {
1473 // We haven't processed this record type before.
1474 // Queue up this v-table for possible deferred emission.
1475 CGM.addDeferredVTable(RD);
1478 // Create all the vftables at once in order to make sure each vftable has
1479 // a unique mangled name.
1480 llvm::StringSet<> ObservedMangledNames;
1481 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1482 SmallString<256> Name;
1483 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1484 if (!ObservedMangledNames.insert(Name.str()).second)
1485 llvm_unreachable("Already saw this mangling before?");
1490 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1491 if (VFPtrs[J]->FullOffsetInMDC != VPtrOffset)
1493 SmallString<256> VFTableName;
1494 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], VFTableName);
1495 StringRef VTableName = VFTableName;
1497 uint64_t NumVTableSlots =
1498 VTContext.getVFTableLayout(RD, VFPtrs[J]->FullOffsetInMDC)
1499 .getNumVTableComponents();
1500 llvm::GlobalValue::LinkageTypes VTableLinkage =
1501 llvm::GlobalValue::ExternalLinkage;
1502 llvm::ArrayType *VTableType =
1503 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1504 if (getContext().getLangOpts().RTTIData) {
1505 VTableLinkage = llvm::GlobalValue::PrivateLinkage;
1509 VTable = CGM.getModule().getNamedGlobal(VFTableName);
1511 // Create a backing variable for the contents of VTable. The VTable may
1512 // or may not include space for a pointer to RTTI data.
1513 llvm::GlobalValue *VFTable = VTable = new llvm::GlobalVariable(
1514 CGM.getModule(), VTableType, /*isConstant=*/true, VTableLinkage,
1515 /*Initializer=*/nullptr, VTableName);
1516 VTable->setUnnamedAddr(true);
1518 // Only insert a pointer into the VFTable for RTTI data if we are not
1519 // importing it. We never reference the RTTI data directly so there is no
1520 // need to make room for it.
1521 if (getContext().getLangOpts().RTTIData &&
1522 !RD->hasAttr<DLLImportAttr>()) {
1523 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1524 llvm::ConstantInt::get(CGM.IntTy, 1)};
1525 // Create a GEP which points just after the first entry in the VFTable,
1526 // this should be the location of the first virtual method.
1527 llvm::Constant *VTableGEP =
1528 llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, GEPIndices);
1529 // The symbol for the VFTable is an alias to the GEP. It is
1530 // transparent, to other modules, what the nature of this symbol is; all
1531 // that matters is that the alias be the address of the first virtual
1533 VFTable = llvm::GlobalAlias::create(
1534 cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(),
1535 /*AddressSpace=*/0, llvm::GlobalValue::ExternalLinkage,
1536 VFTableName.str(), VTableGEP, &CGM.getModule());
1538 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1539 // be referencing any RTTI data. The GlobalVariable will end up being
1540 // an appropriate definition of the VFTable.
1541 VTable->setName(VFTableName.str());
1544 VFTable->setUnnamedAddr(true);
1545 if (RD->hasAttr<DLLImportAttr>())
1546 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1547 else if (RD->hasAttr<DLLExportAttr>())
1548 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1550 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1551 if (VFTable != VTable) {
1552 if (llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage)) {
1553 // AvailableExternally implies that we grabbed the data from another
1554 // executable. No need to stick the alias in a Comdat.
1555 } else if (llvm::GlobalValue::isInternalLinkage(VFTableLinkage) ||
1556 llvm::GlobalValue::isWeakODRLinkage(VFTableLinkage) ||
1557 llvm::GlobalValue::isLinkOnceODRLinkage(VFTableLinkage)) {
1558 // The alias is going to be dropped into a Comdat, no need to make it
1560 if (!llvm::GlobalValue::isInternalLinkage(VFTableLinkage))
1561 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1563 CGM.getModule().getOrInsertComdat(VFTable->getName());
1564 // We must indicate which VFTable is larger to support linking between
1565 // translation units which do and do not have RTTI data. The largest
1566 // VFTable contains the RTTI data; translation units which reference
1567 // the smaller VFTable always reference it relative to the first
1569 C->setSelectionKind(llvm::Comdat::Largest);
1570 VTable->setComdat(C);
1572 llvm_unreachable("unexpected linkage for vftable!");
1575 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage))
1577 CGM.getModule().getOrInsertComdat(VTable->getName()));
1579 VFTable->setLinkage(VFTableLinkage);
1580 CGM.setGlobalVisibility(VFTable, RD);
1581 VFTablesMap[ID] = VFTable;
1589 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1593 GD = GD.getCanonicalDecl();
1594 CGBuilderTy &Builder = CGF.Builder;
1596 Ty = Ty->getPointerTo()->getPointerTo();
1598 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1599 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1601 MicrosoftVTableContext::MethodVFTableLocation ML =
1602 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1603 llvm::Value *VFuncPtr =
1604 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1605 return Builder.CreateLoad(VFuncPtr);
1608 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1609 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1610 llvm::Value *This, const CXXMemberCallExpr *CE) {
1611 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1612 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1614 // We have only one destructor in the vftable but can get both behaviors
1615 // by passing an implicit int parameter.
1616 GlobalDecl GD(Dtor, Dtor_Deleting);
1617 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1618 Dtor, StructorType::Deleting);
1619 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1620 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1622 ASTContext &Context = getContext();
1623 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1624 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1625 DtorType == Dtor_Deleting);
1627 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1628 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1629 ImplicitParam, Context.IntTy, CE,
1630 StructorType::Deleting);
1631 return RV.getScalarVal();
1634 const VBTableGlobals &
1635 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1636 // At this layer, we can key the cache off of a single class, which is much
1637 // easier than caching each vbtable individually.
1638 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1640 std::tie(Entry, Added) =
1641 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1642 VBTableGlobals &VBGlobals = Entry->second;
1646 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1647 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1649 // Cache the globals for all vbtables so we don't have to recompute the
1651 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1652 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1653 E = VBGlobals.VBTables->end();
1655 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1661 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1662 const CXXMethodDecl *MD,
1663 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1664 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1665 "can't form pointers to ctors or virtual dtors");
1667 // Calculate the mangled name.
1668 SmallString<256> ThunkName;
1669 llvm::raw_svector_ostream Out(ThunkName);
1670 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1673 // If the thunk has been generated previously, just return it.
1674 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1675 return cast<llvm::Function>(GV);
1677 // Create the llvm::Function.
1678 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1679 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1680 llvm::Function *ThunkFn =
1681 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1682 ThunkName.str(), &CGM.getModule());
1683 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1685 ThunkFn->setLinkage(MD->isExternallyVisible()
1686 ? llvm::GlobalValue::LinkOnceODRLinkage
1687 : llvm::GlobalValue::InternalLinkage);
1688 if (MD->isExternallyVisible())
1689 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1691 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1692 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1694 // Add the "thunk" attribute so that LLVM knows that the return type is
1695 // meaningless. These thunks can be used to call functions with differing
1696 // return types, and the caller is required to cast the prototype
1697 // appropriately to extract the correct value.
1698 ThunkFn->addFnAttr("thunk");
1700 // These thunks can be compared, so they are not unnamed.
1701 ThunkFn->setUnnamedAddr(false);
1704 CodeGenFunction CGF(CGM);
1705 CGF.CurGD = GlobalDecl(MD);
1706 CGF.CurFuncIsThunk = true;
1708 // Build FunctionArgs, but only include the implicit 'this' parameter
1710 FunctionArgList FunctionArgs;
1711 buildThisParam(CGF, FunctionArgs);
1713 // Start defining the function.
1714 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1715 FunctionArgs, MD->getLocation(), SourceLocation());
1718 // Load the vfptr and then callee from the vftable. The callee should have
1719 // adjusted 'this' so that the vfptr is at offset zero.
1720 llvm::Value *VTable = CGF.GetVTablePtr(
1721 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1722 llvm::Value *VFuncPtr =
1723 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1724 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1726 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1731 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1732 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1733 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1734 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1735 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1736 if (GV->isDeclaration())
1737 emitVBTableDefinition(*VBT, RD, GV);
1741 llvm::GlobalVariable *
1742 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1743 llvm::GlobalVariable::LinkageTypes Linkage) {
1744 SmallString<256> OutName;
1745 llvm::raw_svector_ostream Out(OutName);
1746 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1748 StringRef Name = OutName.str();
1750 llvm::ArrayType *VBTableType =
1751 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1753 assert(!CGM.getModule().getNamedGlobal(Name) &&
1754 "vbtable with this name already exists: mangling bug?");
1755 llvm::GlobalVariable *GV =
1756 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1757 GV->setUnnamedAddr(true);
1759 if (RD->hasAttr<DLLImportAttr>())
1760 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1761 else if (RD->hasAttr<DLLExportAttr>())
1762 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1764 if (!GV->hasExternalLinkage())
1765 emitVBTableDefinition(VBT, RD, GV);
1770 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1771 const CXXRecordDecl *RD,
1772 llvm::GlobalVariable *GV) const {
1773 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1775 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1776 "should only emit vbtables for classes with vbtables");
1778 const ASTRecordLayout &BaseLayout =
1779 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1780 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1782 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1785 // The offset from ReusingBase's vbptr to itself always leads.
1786 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1787 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1789 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1790 for (const auto &I : ReusingBase->vbases()) {
1791 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1792 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1793 assert(!Offset.isNegative());
1795 // Make it relative to the subobject vbptr.
1796 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1797 if (VBT.getVBaseWithVPtr())
1798 CompleteVBPtrOffset +=
1799 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1800 Offset -= CompleteVBPtrOffset;
1802 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1803 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1804 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1807 assert(Offsets.size() ==
1808 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1809 ->getElementType())->getNumElements());
1810 llvm::ArrayType *VBTableType =
1811 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1812 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1813 GV->setInitializer(Init);
1815 // Set the right visibility.
1816 CGM.setGlobalVisibility(GV, RD);
1819 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1821 const ThisAdjustment &TA) {
1825 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1827 if (!TA.Virtual.isEmpty()) {
1828 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1829 // Adjust the this argument based on the vtordisp value.
1830 llvm::Value *VtorDispPtr =
1831 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1833 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1834 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1835 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1837 if (TA.Virtual.Microsoft.VBPtrOffset) {
1838 // If the final overrider is defined in a virtual base other than the one
1839 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1840 // the vbtable of the derived class.
1841 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1842 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1844 llvm::Value *VBaseOffset =
1845 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1846 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1847 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1851 if (TA.NonVirtual) {
1852 // Non-virtual adjustment might result in a pointer outside the allocated
1853 // object, e.g. if the final overrider class is laid out after the virtual
1854 // base that declares a method in the most derived class.
1855 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1858 // Don't need to bitcast back, the call CodeGen will handle this.
1863 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1864 const ReturnAdjustment &RA) {
1868 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1870 if (RA.Virtual.Microsoft.VBIndex) {
1871 assert(RA.Virtual.Microsoft.VBIndex > 0);
1872 const ASTContext &Context = getContext();
1873 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
1875 llvm::Value *VBaseOffset =
1876 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1877 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1878 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1882 V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual);
1884 // Cast back to the original type.
1885 return CGF.Builder.CreateBitCast(V, Ret->getType());
1888 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1889 QualType elementType) {
1890 // Microsoft seems to completely ignore the possibility of a
1891 // two-argument usual deallocation function.
1892 return elementType.isDestructedType();
1895 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1896 // Microsoft seems to completely ignore the possibility of a
1897 // two-argument usual deallocation function.
1898 return expr->getAllocatedType().isDestructedType();
1901 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1902 // The array cookie is always a size_t; we then pad that out to the
1903 // alignment of the element type.
1904 ASTContext &Ctx = getContext();
1905 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1906 Ctx.getTypeAlignInChars(type));
1909 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1910 llvm::Value *allocPtr,
1911 CharUnits cookieSize) {
1912 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1913 llvm::Value *numElementsPtr =
1914 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1915 return CGF.Builder.CreateLoad(numElementsPtr);
1918 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1919 llvm::Value *newPtr,
1920 llvm::Value *numElements,
1921 const CXXNewExpr *expr,
1922 QualType elementType) {
1923 assert(requiresArrayCookie(expr));
1925 // The size of the cookie.
1926 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1928 // Compute an offset to the cookie.
1929 llvm::Value *cookiePtr = newPtr;
1931 // Write the number of elements into the appropriate slot.
1932 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1933 llvm::Value *numElementsPtr
1934 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1935 CGF.Builder.CreateStore(numElements, numElementsPtr);
1937 // Finally, compute a pointer to the actual data buffer by skipping
1938 // over the cookie completely.
1939 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1940 cookieSize.getQuantity());
1943 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
1944 llvm::Constant *Dtor,
1945 llvm::Constant *Addr) {
1946 // Create a function which calls the destructor.
1947 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
1949 // extern "C" int __tlregdtor(void (*f)(void));
1950 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
1951 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
1953 llvm::Constant *TLRegDtor =
1954 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
1955 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
1956 TLRegDtorFn->setDoesNotThrow();
1958 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
1961 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
1962 llvm::Constant *Dtor,
1963 llvm::Constant *Addr) {
1965 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
1967 // The default behavior is to use atexit.
1968 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
1971 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
1973 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
1975 ArrayRef<llvm::Function *> CXXThreadLocalInits,
1976 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
1977 // This will create a GV in the .CRT$XDU section. It will point to our
1978 // initialization function. The CRT will call all of these function
1979 // pointers at start-up time and, eventually, at thread-creation time.
1980 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
1981 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
1982 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
1983 llvm::GlobalVariable::InternalLinkage, InitFunc,
1984 Twine(InitFunc->getName(), "$initializer$"));
1985 InitFuncPtr->setSection(".CRT$XDU");
1986 // This variable has discardable linkage, we have to add it to @llvm.used to
1987 // ensure it won't get discarded.
1988 CGM.addUsedGlobal(InitFuncPtr);
1992 std::vector<llvm::Function *> NonComdatInits;
1993 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
1994 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
1995 llvm::Function *F = CXXThreadLocalInits[I];
1997 // If the GV is already in a comdat group, then we have to join it.
1998 if (llvm::Comdat *C = GV->getComdat())
1999 AddToXDU(F)->setComdat(C);
2001 NonComdatInits.push_back(F);
2004 if (!NonComdatInits.empty()) {
2005 llvm::FunctionType *FTy =
2006 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2007 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2008 FTy, "__tls_init", SourceLocation(),
2010 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2016 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2018 QualType LValType) {
2019 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2023 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2024 llvm::GlobalVariable *GV,
2026 // MSVC only uses guards for static locals.
2027 if (!D.isStaticLocal()) {
2028 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2029 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2030 llvm::Function *F = CGF.CurFn;
2031 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2032 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2033 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2037 // MSVC always uses an i32 bitfield to guard initialization, which is *not*
2038 // threadsafe. Since the user may be linking in inline functions compiled by
2039 // cl.exe, there's no reason to provide a false sense of security by using
2040 // critical sections here.
2043 CGM.ErrorUnsupported(&D, "dynamic TLS initialization");
2045 CGBuilderTy &Builder = CGF.Builder;
2046 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2047 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2049 // Get the guard variable for this function if we have one already.
2050 GuardInfo *GI = &GuardVariableMap[D.getDeclContext()];
2053 if (D.isStaticLocal() && D.isExternallyVisible()) {
2054 // Externally visible variables have to be numbered in Sema to properly
2055 // handle unreachable VarDecls.
2056 BitIndex = getContext().getStaticLocalNumber(&D);
2057 assert(BitIndex > 0);
2060 // Non-externally visible variables are numbered here in CodeGen.
2061 BitIndex = GI->BitIndex++;
2064 if (BitIndex >= 32) {
2065 if (D.isExternallyVisible())
2066 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2068 GI->Guard = nullptr;
2071 // Lazily create the i32 bitfield for this function.
2073 // Mangle the name for the guard.
2074 SmallString<256> GuardName;
2076 llvm::raw_svector_ostream Out(GuardName);
2077 getMangleContext().mangleStaticGuardVariable(&D, Out);
2081 // Create the guard variable with a zero-initializer. Just absorb linkage,
2082 // visibility and dll storage class from the guarded variable.
2084 new llvm::GlobalVariable(CGM.getModule(), GuardTy, false,
2085 GV->getLinkage(), Zero, GuardName.str());
2086 GI->Guard->setVisibility(GV->getVisibility());
2087 GI->Guard->setDLLStorageClass(GV->getDLLStorageClass());
2088 if (GI->Guard->isWeakForLinker())
2089 GI->Guard->setComdat(
2090 CGM.getModule().getOrInsertComdat(GI->Guard->getName()));
2092 assert(GI->Guard->getLinkage() == GV->getLinkage() &&
2093 "static local from the same function had different linkage");
2096 // Pseudo code for the test:
2097 // if (!(GuardVar & MyGuardBit)) {
2098 // GuardVar |= MyGuardBit;
2099 // ... initialize the object ...;
2102 // Test our bit from the guard variable.
2103 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << BitIndex);
2104 llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard);
2105 llvm::Value *IsInitialized =
2106 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2107 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2108 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2109 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2111 // Set our bit in the guard variable and emit the initializer and add a global
2112 // destructor if appropriate.
2113 CGF.EmitBlock(InitBlock);
2114 Builder.CreateStore(Builder.CreateOr(LI, Bit), GI->Guard);
2115 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2116 Builder.CreateBr(EndBlock);
2119 CGF.EmitBlock(EndBlock);
2122 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2123 // Null-ness for function memptrs only depends on the first field, which is
2124 // the function pointer. The rest don't matter, so we can zero initialize.
2125 if (MPT->isMemberFunctionPointer())
2128 // The virtual base adjustment field is always -1 for null, so if we have one
2129 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2130 // valid field offset.
2131 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2132 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2133 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2134 RD->nullFieldOffsetIsZero());
2138 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2139 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2140 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2141 llvm::SmallVector<llvm::Type *, 4> fields;
2142 if (MPT->isMemberFunctionPointer())
2143 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2145 fields.push_back(CGM.IntTy); // FieldOffset
2147 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2149 fields.push_back(CGM.IntTy);
2150 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2151 fields.push_back(CGM.IntTy);
2152 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2153 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2155 if (fields.size() == 1)
2157 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2160 void MicrosoftCXXABI::
2161 GetNullMemberPointerFields(const MemberPointerType *MPT,
2162 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2163 assert(fields.empty());
2164 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2165 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2166 if (MPT->isMemberFunctionPointer()) {
2167 // FunctionPointerOrVirtualThunk
2168 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2170 if (RD->nullFieldOffsetIsZero())
2171 fields.push_back(getZeroInt()); // FieldOffset
2173 fields.push_back(getAllOnesInt()); // FieldOffset
2176 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2178 fields.push_back(getZeroInt());
2179 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2180 fields.push_back(getZeroInt());
2181 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2182 fields.push_back(getAllOnesInt());
2186 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2187 llvm::SmallVector<llvm::Constant *, 4> fields;
2188 GetNullMemberPointerFields(MPT, fields);
2189 if (fields.size() == 1)
2191 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2192 assert(Res->getType() == ConvertMemberPointerType(MPT));
2197 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2198 bool IsMemberFunction,
2199 const CXXRecordDecl *RD,
2200 CharUnits NonVirtualBaseAdjustment)
2202 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2204 // Single inheritance class member pointer are represented as scalars instead
2206 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2209 llvm::SmallVector<llvm::Constant *, 4> fields;
2210 fields.push_back(FirstField);
2212 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2213 fields.push_back(llvm::ConstantInt::get(
2214 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2216 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2217 CharUnits Offs = CharUnits::Zero();
2218 if (RD->getNumVBases())
2219 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2220 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2223 // The rest of the fields are adjusted by conversions to a more derived class.
2224 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2225 fields.push_back(getZeroInt());
2227 return llvm::ConstantStruct::getAnon(fields);
2231 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2233 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2234 llvm::Constant *FirstField =
2235 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2236 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2240 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
2241 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
2244 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2246 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
2247 const ValueDecl *MPD = MP.getMemberPointerDecl();
2249 return EmitNullMemberPointer(MPT);
2251 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
2253 // FIXME PR15713: Support virtual inheritance paths.
2255 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
2256 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
2259 CharUnits FieldOffset =
2260 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
2261 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
2265 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
2266 const CXXMethodDecl *MD,
2267 CharUnits NonVirtualBaseAdjustment) {
2268 assert(MD->isInstance() && "Member function must not be static!");
2269 MD = MD->getCanonicalDecl();
2270 RD = RD->getMostRecentDecl();
2271 CodeGenTypes &Types = CGM.getTypes();
2273 llvm::Constant *FirstField;
2274 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2275 if (!MD->isVirtual()) {
2277 // Check whether the function has a computable LLVM signature.
2278 if (Types.isFuncTypeConvertible(FPT)) {
2279 // The function has a computable LLVM signature; use the correct type.
2280 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2282 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2283 // function type is incomplete.
2286 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2287 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2289 MicrosoftVTableContext::MethodVFTableLocation ML =
2290 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
2291 if (!CGM.getTypes().isFuncTypeConvertible(
2292 MD->getType()->castAs<FunctionType>())) {
2293 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
2294 "incomplete return or parameter type");
2295 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2296 } else if (FPT->getCallConv() == CC_X86FastCall) {
2297 CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
2298 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2299 } else if (ML.VBase) {
2300 CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding "
2301 "member function in virtual base class");
2302 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2304 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2305 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2306 // Include the vfptr adjustment if the method is in a non-primary vftable.
2307 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2311 // The rest of the fields are common with data member pointers.
2312 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2313 NonVirtualBaseAdjustment);
2316 /// Member pointers are the same if they're either bitwise identical *or* both
2317 /// null. Null-ness for function members is determined by the first field,
2318 /// while for data member pointers we must compare all fields.
2320 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2323 const MemberPointerType *MPT,
2325 CGBuilderTy &Builder = CGF.Builder;
2327 // Handle != comparisons by switching the sense of all boolean operations.
2328 llvm::ICmpInst::Predicate Eq;
2329 llvm::Instruction::BinaryOps And, Or;
2331 Eq = llvm::ICmpInst::ICMP_NE;
2332 And = llvm::Instruction::Or;
2333 Or = llvm::Instruction::And;
2335 Eq = llvm::ICmpInst::ICMP_EQ;
2336 And = llvm::Instruction::And;
2337 Or = llvm::Instruction::Or;
2340 // If this is a single field member pointer (single inheritance), this is a
2342 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2343 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2344 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2346 return Builder.CreateICmp(Eq, L, R);
2348 // Compare the first field.
2349 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2350 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2351 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2353 // Compare everything other than the first field.
2354 llvm::Value *Res = nullptr;
2355 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2356 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2357 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2358 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2359 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2361 Res = Builder.CreateBinOp(And, Res, Cmp);
2366 // Check if the first field is 0 if this is a function pointer.
2367 if (MPT->isMemberFunctionPointer()) {
2368 // (l1 == r1 && ...) || l0 == 0
2369 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2370 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2371 Res = Builder.CreateBinOp(Or, Res, IsZero);
2374 // Combine the comparison of the first field, which must always be true for
2375 // this comparison to succeeed.
2376 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2380 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2381 llvm::Value *MemPtr,
2382 const MemberPointerType *MPT) {
2383 CGBuilderTy &Builder = CGF.Builder;
2384 llvm::SmallVector<llvm::Constant *, 4> fields;
2385 // We only need one field for member functions.
2386 if (MPT->isMemberFunctionPointer())
2387 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2389 GetNullMemberPointerFields(MPT, fields);
2390 assert(!fields.empty());
2391 llvm::Value *FirstField = MemPtr;
2392 if (MemPtr->getType()->isStructTy())
2393 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2394 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2396 // For function member pointers, we only need to test the function pointer
2397 // field. The other fields if any can be garbage.
2398 if (MPT->isMemberFunctionPointer())
2401 // Otherwise, emit a series of compares and combine the results.
2402 for (int I = 1, E = fields.size(); I < E; ++I) {
2403 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2404 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2405 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2410 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2411 llvm::Constant *Val) {
2412 // Function pointers are null if the pointer in the first field is null.
2413 if (MPT->isMemberFunctionPointer()) {
2414 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2415 Val->getAggregateElement(0U) : Val;
2416 return FirstField->isNullValue();
2419 // If it's not a function pointer and it's zero initializable, we can easily
2421 if (isZeroInitializable(MPT) && Val->isNullValue())
2424 // Otherwise, break down all the fields for comparison. Hopefully these
2425 // little Constants are reused, while a big null struct might not be.
2426 llvm::SmallVector<llvm::Constant *, 4> Fields;
2427 GetNullMemberPointerFields(MPT, Fields);
2428 if (Fields.size() == 1) {
2429 assert(Val->getType()->isIntegerTy());
2430 return Val == Fields[0];
2434 for (I = 0, E = Fields.size(); I != E; ++I) {
2435 if (Val->getAggregateElement(I) != Fields[I])
2442 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2444 llvm::Value *VBPtrOffset,
2445 llvm::Value *VBTableOffset,
2446 llvm::Value **VBPtrOut) {
2447 CGBuilderTy &Builder = CGF.Builder;
2448 // Load the vbtable pointer from the vbptr in the instance.
2449 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2450 llvm::Value *VBPtr =
2451 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2452 if (VBPtrOut) *VBPtrOut = VBPtr;
2453 VBPtr = Builder.CreateBitCast(VBPtr,
2454 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2455 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2457 // Translate from byte offset to table index. It improves analyzability.
2458 llvm::Value *VBTableIndex = Builder.CreateAShr(
2459 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2460 "vbtindex", /*isExact=*/true);
2462 // Load an i32 offset from the vb-table.
2463 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2464 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2465 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2468 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2470 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2471 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2472 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2473 CGBuilderTy &Builder = CGF.Builder;
2474 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2475 llvm::BasicBlock *OriginalBB = nullptr;
2476 llvm::BasicBlock *SkipAdjustBB = nullptr;
2477 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2479 // In the unspecified inheritance model, there might not be a vbtable at all,
2480 // in which case we need to skip the virtual base lookup. If there is a
2481 // vbtable, the first entry is a no-op entry that gives back the original
2482 // base, so look for a virtual base adjustment offset of zero.
2484 OriginalBB = Builder.GetInsertBlock();
2485 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2486 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2487 llvm::Value *IsVirtual =
2488 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2490 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2491 CGF.EmitBlock(VBaseAdjustBB);
2494 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2495 // know the vbptr offset.
2497 CharUnits offs = CharUnits::Zero();
2498 if (!RD->hasDefinition()) {
2499 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2500 unsigned DiagID = Diags.getCustomDiagID(
2501 DiagnosticsEngine::Error,
2502 "member pointer representation requires a "
2503 "complete class type for %0 to perform this expression");
2504 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2505 } else if (RD->getNumVBases())
2506 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2507 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2509 llvm::Value *VBPtr = nullptr;
2510 llvm::Value *VBaseOffs =
2511 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2512 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2514 // Merge control flow with the case where we didn't have to adjust.
2515 if (VBaseAdjustBB) {
2516 Builder.CreateBr(SkipAdjustBB);
2517 CGF.EmitBlock(SkipAdjustBB);
2518 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2519 Phi->addIncoming(Base, OriginalBB);
2520 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2523 return AdjustedBase;
2526 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2527 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2528 const MemberPointerType *MPT) {
2529 assert(MPT->isMemberDataPointer());
2530 unsigned AS = Base->getType()->getPointerAddressSpace();
2532 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2533 CGBuilderTy &Builder = CGF.Builder;
2534 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2535 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2537 // Extract the fields we need, regardless of model. We'll apply them if we
2539 llvm::Value *FieldOffset = MemPtr;
2540 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2541 llvm::Value *VBPtrOffset = nullptr;
2542 if (MemPtr->getType()->isStructTy()) {
2543 // We need to extract values.
2545 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2546 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2547 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2548 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2549 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2552 if (VirtualBaseAdjustmentOffset) {
2553 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2558 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2560 // Apply the offset, which we assume is non-null.
2562 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2564 // Cast the address to the appropriate pointer type, adopting the address
2565 // space of the base pointer.
2566 return Builder.CreateBitCast(Addr, PType);
2569 static MSInheritanceAttr::Spelling
2570 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2571 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2575 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2578 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2579 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2580 E->getCastKind() == CK_ReinterpretMemberPointer);
2582 // Use constant emission if we can.
2583 if (isa<llvm::Constant>(Src))
2584 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2586 // We may be adding or dropping fields from the member pointer, so we need
2587 // both types and the inheritance models of both records.
2588 const MemberPointerType *SrcTy =
2589 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2590 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2591 bool IsFunc = SrcTy->isMemberFunctionPointer();
2593 // If the classes use the same null representation, reinterpret_cast is a nop.
2594 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2595 if (IsReinterpret && IsFunc)
2598 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2599 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2600 if (IsReinterpret &&
2601 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2604 CGBuilderTy &Builder = CGF.Builder;
2606 // Branch past the conversion if Src is null.
2607 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2608 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2610 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2611 // pointer value of the destination type.
2612 if (IsReinterpret) {
2613 // For reinterpret casts, sema ensures that src and dst are both functions
2614 // or data and have the same size, which means the LLVM types should match.
2615 assert(Src->getType() == DstNull->getType());
2616 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2619 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2620 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2621 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2622 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2623 CGF.EmitBlock(ConvertBB);
2626 llvm::Value *FirstField = Src;
2627 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2628 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2629 llvm::Value *VBPtrOffset = nullptr;
2630 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2631 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2632 // We need to extract values.
2634 FirstField = Builder.CreateExtractValue(Src, I++);
2635 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2636 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2637 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2638 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2639 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2640 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2643 // For data pointers, we adjust the field offset directly. For functions, we
2644 // have a separate field.
2645 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2647 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2648 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2649 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2650 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2651 NVAdjustField = getZeroInt();
2652 if (isDerivedToBase)
2653 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2655 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2658 // FIXME PR15713: Support conversions through virtually derived classes.
2660 // Recompose dst from the null struct and the adjusted fields from src.
2661 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2663 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2666 Dst = llvm::UndefValue::get(DstNull->getType());
2668 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2669 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2670 Dst = Builder.CreateInsertValue(
2671 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2672 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2673 Dst = Builder.CreateInsertValue(
2674 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2675 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2676 Dst = Builder.CreateInsertValue(
2677 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2679 Builder.CreateBr(ContinueBB);
2681 // In the continuation, choose between DstNull and Dst.
2682 CGF.EmitBlock(ContinueBB);
2683 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2684 Phi->addIncoming(DstNull, OriginalBB);
2685 Phi->addIncoming(Dst, ConvertBB);
2690 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2691 llvm::Constant *Src) {
2692 const MemberPointerType *SrcTy =
2693 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2694 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2696 // If src is null, emit a new null for dst. We can't return src because dst
2697 // might have a new representation.
2698 if (MemberPointerConstantIsNull(SrcTy, Src))
2699 return EmitNullMemberPointer(DstTy);
2701 // We don't need to do anything for reinterpret_casts of non-null member
2702 // pointers. We should only get here when the two type representations have
2704 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2707 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2708 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2711 llvm::Constant *FirstField = Src;
2712 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2713 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2714 llvm::Constant *VBPtrOffset = nullptr;
2715 bool IsFunc = SrcTy->isMemberFunctionPointer();
2716 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2717 // We need to extract values.
2719 FirstField = Src->getAggregateElement(I++);
2720 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2721 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2722 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2723 VBPtrOffset = Src->getAggregateElement(I++);
2724 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2725 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2728 // For data pointers, we adjust the field offset directly. For functions, we
2729 // have a separate field.
2730 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2732 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2733 llvm::Constant *&NVAdjustField =
2734 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2735 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2736 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2737 NVAdjustField = getZeroInt();
2738 if (IsDerivedToBase)
2739 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2741 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2744 // FIXME PR15713: Support conversions through virtually derived classes.
2746 // Recompose dst from the null struct and the adjusted fields from src.
2747 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2750 llvm::SmallVector<llvm::Constant *, 4> Fields;
2751 Fields.push_back(FirstField);
2752 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2753 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2754 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2755 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2756 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2757 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2758 return llvm::ConstantStruct::getAnon(Fields);
2761 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2762 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2763 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2764 assert(MPT->isMemberFunctionPointer());
2765 const FunctionProtoType *FPT =
2766 MPT->getPointeeType()->castAs<FunctionProtoType>();
2767 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2768 llvm::FunctionType *FTy =
2769 CGM.getTypes().GetFunctionType(
2770 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2771 CGBuilderTy &Builder = CGF.Builder;
2773 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2775 // Extract the fields we need, regardless of model. We'll apply them if we
2777 llvm::Value *FunctionPointer = MemPtr;
2778 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2779 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2780 llvm::Value *VBPtrOffset = nullptr;
2781 if (MemPtr->getType()->isStructTy()) {
2782 // We need to extract values.
2784 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2785 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2786 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2787 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2788 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2789 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2790 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2793 if (VirtualBaseAdjustmentOffset) {
2794 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2798 if (NonVirtualBaseAdjustment) {
2799 // Apply the adjustment and cast back to the original struct type.
2800 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2801 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2802 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2805 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2808 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2809 return new MicrosoftCXXABI(CGM);
2812 // MS RTTI Overview:
2813 // The run time type information emitted by cl.exe contains 5 distinct types of
2814 // structures. Many of them reference each other.
2816 // TypeInfo: Static classes that are returned by typeid.
2818 // CompleteObjectLocator: Referenced by vftables. They contain information
2819 // required for dynamic casting, including OffsetFromTop. They also contain
2820 // a reference to the TypeInfo for the type and a reference to the
2821 // CompleteHierarchyDescriptor for the type.
2823 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2824 // Used during dynamic_cast to walk a class hierarchy. References a base
2825 // class array and the size of said array.
2827 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2828 // somewhat of a misnomer because the most derived class is also in the list
2829 // as well as multiple copies of virtual bases (if they occur multiple times
2830 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2831 // every path in the hierarchy, in pre-order depth first order. Note, we do
2832 // not declare a specific llvm type for BaseClassArray, it's merely an array
2833 // of BaseClassDescriptor pointers.
2835 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2836 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2837 // BaseClassArray is. It contains information about a class within a
2838 // hierarchy such as: is this base is ambiguous and what is its offset in the
2839 // vbtable. The names of the BaseClassDescriptors have all of their fields
2840 // mangled into them so they can be aggressively deduplicated by the linker.
2842 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2843 StringRef MangledName("\01??_7type_info@@6B@");
2844 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2846 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2848 llvm::GlobalVariable::ExternalLinkage,
2849 /*Initializer=*/nullptr, MangledName);
2854 /// \brief A Helper struct that stores information about a class in a class
2855 /// hierarchy. The information stored in these structs struct is used during
2856 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2857 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2858 // implicit depth first pre-order tree connectivity. getFirstChild and
2859 // getNextSibling allow us to walk the tree efficiently.
2860 struct MSRTTIClass {
2862 IsPrivateOnPath = 1 | 8,
2866 HasHierarchyDescriptor = 64
2868 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
2869 uint32_t initialize(const MSRTTIClass *Parent,
2870 const CXXBaseSpecifier *Specifier);
2872 MSRTTIClass *getFirstChild() { return this + 1; }
2873 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
2874 return Child + 1 + Child->NumBases;
2877 const CXXRecordDecl *RD, *VirtualRoot;
2878 uint32_t Flags, NumBases, OffsetInVBase;
2881 /// \brief Recursively initialize the base class array.
2882 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
2883 const CXXBaseSpecifier *Specifier) {
2884 Flags = HasHierarchyDescriptor;
2886 VirtualRoot = nullptr;
2889 if (Specifier->getAccessSpecifier() != AS_public)
2890 Flags |= IsPrivate | IsPrivateOnPath;
2891 if (Specifier->isVirtual()) {
2896 if (Parent->Flags & IsPrivateOnPath)
2897 Flags |= IsPrivateOnPath;
2898 VirtualRoot = Parent->VirtualRoot;
2899 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
2900 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
2904 MSRTTIClass *Child = getFirstChild();
2905 for (const CXXBaseSpecifier &Base : RD->bases()) {
2906 NumBases += Child->initialize(this, &Base) + 1;
2907 Child = getNextChild(Child);
2912 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
2913 switch (Ty->getLinkage()) {
2915 case InternalLinkage:
2916 case UniqueExternalLinkage:
2917 return llvm::GlobalValue::InternalLinkage;
2919 case VisibleNoLinkage:
2920 case ExternalLinkage:
2921 return llvm::GlobalValue::LinkOnceODRLinkage;
2923 llvm_unreachable("Invalid linkage!");
2926 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
2927 /// calls to the module and information about the most derived class in a
2929 struct MSRTTIBuilder {
2931 HasBranchingHierarchy = 1,
2932 HasVirtualBranchingHierarchy = 2,
2933 HasAmbiguousBases = 4
2936 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
2937 : CGM(ABI.CGM), Context(CGM.getContext()),
2938 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
2939 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
2942 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
2943 llvm::GlobalVariable *
2944 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
2945 llvm::GlobalVariable *getClassHierarchyDescriptor();
2946 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
2949 ASTContext &Context;
2950 llvm::LLVMContext &VMContext;
2951 llvm::Module &Module;
2952 const CXXRecordDecl *RD;
2953 llvm::GlobalVariable::LinkageTypes Linkage;
2954 MicrosoftCXXABI &ABI;
2959 /// \brief Recursively serializes a class hierarchy in pre-order depth first
2961 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
2962 const CXXRecordDecl *RD) {
2963 Classes.push_back(MSRTTIClass(RD));
2964 for (const CXXBaseSpecifier &Base : RD->bases())
2965 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
2968 /// \brief Find ambiguity among base classes.
2970 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
2971 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
2972 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
2973 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
2974 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
2975 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
2976 !VirtualBases.insert(Class->RD).second) {
2977 Class = MSRTTIClass::getNextChild(Class);
2980 if (!UniqueBases.insert(Class->RD).second)
2981 AmbiguousBases.insert(Class->RD);
2984 if (AmbiguousBases.empty())
2986 for (MSRTTIClass &Class : Classes)
2987 if (AmbiguousBases.count(Class.RD))
2988 Class.Flags |= MSRTTIClass::IsAmbiguous;
2991 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
2992 SmallString<256> MangledName;
2994 llvm::raw_svector_ostream Out(MangledName);
2995 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
2998 // Check to see if we've already declared this ClassHierarchyDescriptor.
2999 if (auto CHD = Module.getNamedGlobal(MangledName))
3002 // Serialize the class hierarchy and initialize the CHD Fields.
3003 SmallVector<MSRTTIClass, 8> Classes;
3004 serializeClassHierarchy(Classes, RD);
3005 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3006 detectAmbiguousBases(Classes);
3008 for (auto Class : Classes) {
3009 if (Class.RD->getNumBases() > 1)
3010 Flags |= HasBranchingHierarchy;
3011 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3012 // believe the field isn't actually used.
3013 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3014 Flags |= HasAmbiguousBases;
3016 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3017 Flags |= HasVirtualBranchingHierarchy;
3018 // These gep indices are used to get the address of the first element of the
3019 // base class array.
3020 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3021 llvm::ConstantInt::get(CGM.IntTy, 0)};
3023 // Forward-declare the class hierarchy descriptor
3024 auto Type = ABI.getClassHierarchyDescriptorType();
3025 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3026 /*Initializer=*/nullptr,
3027 StringRef(MangledName));
3028 if (CHD->isWeakForLinker())
3029 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3031 // Initialize the base class ClassHierarchyDescriptor.
3032 llvm::Constant *Fields[] = {
3033 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3034 llvm::ConstantInt::get(CGM.IntTy, Flags),
3035 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3036 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3037 getBaseClassArray(Classes),
3038 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3040 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3044 llvm::GlobalVariable *
3045 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3046 SmallString<256> MangledName;
3048 llvm::raw_svector_ostream Out(MangledName);
3049 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3052 // Forward-declare the base class array.
3053 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3054 // mode) bytes of padding. We provide a pointer sized amount of padding by
3055 // adding +1 to Classes.size(). The sections have pointer alignment and are
3056 // marked pick-any so it shouldn't matter.
3057 llvm::Type *PtrType = ABI.getImageRelativeType(
3058 ABI.getBaseClassDescriptorType()->getPointerTo());
3059 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3061 new llvm::GlobalVariable(Module, ArrType,
3062 /*Constant=*/true, Linkage,
3063 /*Initializer=*/nullptr, StringRef(MangledName));
3064 if (BCA->isWeakForLinker())
3065 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3067 // Initialize the BaseClassArray.
3068 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3069 for (MSRTTIClass &Class : Classes)
3070 BaseClassArrayData.push_back(
3071 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3072 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3073 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3077 llvm::GlobalVariable *
3078 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3079 // Compute the fields for the BaseClassDescriptor. They are computed up front
3080 // because they are mangled into the name of the object.
3081 uint32_t OffsetInVBTable = 0;
3082 int32_t VBPtrOffset = -1;
3083 if (Class.VirtualRoot) {
3084 auto &VTableContext = CGM.getMicrosoftVTableContext();
3085 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3086 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3089 SmallString<256> MangledName;
3091 llvm::raw_svector_ostream Out(MangledName);
3092 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3093 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3097 // Check to see if we've already declared this object.
3098 if (auto BCD = Module.getNamedGlobal(MangledName))
3101 // Forward-declare the base class descriptor.
3102 auto Type = ABI.getBaseClassDescriptorType();
3104 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3105 /*Initializer=*/nullptr, StringRef(MangledName));
3106 if (BCD->isWeakForLinker())
3107 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3109 // Initialize the BaseClassDescriptor.
3110 llvm::Constant *Fields[] = {
3111 ABI.getImageRelativeConstant(
3112 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3113 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3114 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3115 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3116 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3117 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3118 ABI.getImageRelativeConstant(
3119 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3121 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3125 llvm::GlobalVariable *
3126 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3127 SmallString<256> MangledName;
3129 llvm::raw_svector_ostream Out(MangledName);
3130 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3133 // Check to see if we've already computed this complete object locator.
3134 if (auto COL = Module.getNamedGlobal(MangledName))
3137 // Compute the fields of the complete object locator.
3138 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3139 int VFPtrOffset = 0;
3140 // The offset includes the vtordisp if one exists.
3141 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3142 if (Context.getASTRecordLayout(RD)
3143 .getVBaseOffsetsMap()
3145 ->second.hasVtorDisp())
3146 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3148 // Forward-declare the complete object locator.
3149 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3150 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3151 /*Initializer=*/nullptr, StringRef(MangledName));
3153 // Initialize the CompleteObjectLocator.
3154 llvm::Constant *Fields[] = {
3155 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3156 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3157 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3158 ABI.getImageRelativeConstant(
3159 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3160 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3161 ABI.getImageRelativeConstant(COL),
3163 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3164 if (!ABI.isImageRelative())
3165 FieldsRef = FieldsRef.drop_back();
3166 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3167 if (COL->isWeakForLinker())
3168 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3172 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3173 bool &IsConst, bool &IsVolatile) {
3174 T = Context.getExceptionObjectType(T);
3176 // C++14 [except.handle]p3:
3177 // A handler is a match for an exception object of type E if [...]
3178 // - the handler is of type cv T or const T& where T is a pointer type and
3179 // E is a pointer type that can be converted to T by [...]
3180 // - a qualification conversion
3183 QualType PointeeType = T->getPointeeType();
3184 if (!PointeeType.isNull()) {
3185 IsConst = PointeeType.isConstQualified();
3186 IsVolatile = PointeeType.isVolatileQualified();
3189 // Member pointer types like "const int A::*" are represented by having RTTI
3190 // for "int A::*" and separately storing the const qualifier.
3191 if (const auto *MPTy = T->getAs<MemberPointerType>())
3192 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3195 // Pointer types like "const int * const *" are represented by having RTTI
3196 // for "const int **" and separately storing the const qualifier.
3197 if (T->isPointerType())
3198 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3204 MicrosoftCXXABI::getAddrOfCXXHandlerMapEntry(QualType Type,
3205 QualType CatchHandlerType) {
3206 // TypeDescriptors for exceptions never have qualified pointer types,
3207 // qualifiers are stored seperately in order to support qualification
3209 bool IsConst, IsVolatile;
3210 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3212 bool IsReference = CatchHandlerType->isReferenceType();
3214 SmallString<256> MangledName;
3216 llvm::raw_svector_ostream Out(MangledName);
3217 getMangleContext().mangleCXXHandlerMapEntry(Type, IsConst, IsVolatile,
3221 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3222 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3232 llvm::Constant *Fields[] = {
3233 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3234 getImageRelativeConstant(getAddrOfRTTIDescriptor(Type)), // TypeDescriptor
3236 llvm::StructType *HandlerMapEntryType = getHandlerMapEntryType();
3237 auto *Var = new llvm::GlobalVariable(
3238 CGM.getModule(), HandlerMapEntryType, /*Constant=*/true,
3239 llvm::GlobalValue::PrivateLinkage,
3240 llvm::ConstantStruct::get(HandlerMapEntryType, Fields),
3241 StringRef(MangledName));
3242 Var->setUnnamedAddr(true);
3243 Var->setSection("llvm.metadata");
3247 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3248 /// llvm::GlobalVariable * because different type descriptors have different
3249 /// types, and need to be abstracted. They are abstracting by casting the
3250 /// address to an Int8PtrTy.
3251 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3252 SmallString<256> MangledName;
3254 llvm::raw_svector_ostream Out(MangledName);
3255 getMangleContext().mangleCXXRTTI(Type, Out);
3258 // Check to see if we've already declared this TypeDescriptor.
3259 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3260 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3262 // Compute the fields for the TypeDescriptor.
3263 SmallString<256> TypeInfoString;
3265 llvm::raw_svector_ostream Out(TypeInfoString);
3266 getMangleContext().mangleCXXRTTIName(Type, Out);
3269 // Declare and initialize the TypeDescriptor.
3270 llvm::Constant *Fields[] = {
3271 getTypeInfoVTable(CGM), // VFPtr
3272 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3273 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3274 llvm::StructType *TypeDescriptorType =
3275 getTypeDescriptorType(TypeInfoString);
3276 auto *Var = new llvm::GlobalVariable(
3277 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3278 getLinkageForRTTI(Type),
3279 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3280 StringRef(MangledName));
3281 if (Var->isWeakForLinker())
3282 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3283 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3286 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3287 llvm::GlobalVariable *
3288 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3289 const VPtrInfo *Info) {
3290 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3293 static void emitCXXConstructor(CodeGenModule &CGM,
3294 const CXXConstructorDecl *ctor,
3295 StructorType ctorType) {
3296 // There are no constructor variants, always emit the complete destructor.
3297 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3298 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3301 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3302 StructorType dtorType) {
3303 // The complete destructor is equivalent to the base destructor for
3304 // classes with no virtual bases, so try to emit it as an alias.
3305 if (!dtor->getParent()->getNumVBases() &&
3306 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3307 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3308 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3309 if (ProducedAlias) {
3310 if (dtorType == StructorType::Complete)
3312 if (dtor->isVirtual())
3313 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3317 // The base destructor is equivalent to the base destructor of its
3318 // base class if there is exactly one non-virtual base class with a
3319 // non-trivial destructor, there are no fields with a non-trivial
3320 // destructor, and the body of the destructor is trivial.
3321 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3324 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3325 if (Fn->isWeakForLinker())
3326 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3329 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3330 StructorType Type) {
3331 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3332 emitCXXConstructor(CGM, CD, Type);
3335 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3339 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3341 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3343 // Calculate the mangled name.
3344 SmallString<256> ThunkName;
3345 llvm::raw_svector_ostream Out(ThunkName);
3346 getMangleContext().mangleCXXCtor(CD, CT, Out);
3349 // If the thunk has been generated previously, just return it.
3350 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3351 return cast<llvm::Function>(GV);
3353 // Create the llvm::Function.
3354 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3355 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3356 const CXXRecordDecl *RD = CD->getParent();
3357 QualType RecordTy = getContext().getRecordType(RD);
3358 llvm::Function *ThunkFn = llvm::Function::Create(
3359 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3360 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3361 FnInfo.getEffectiveCallingConvention()));
3362 bool IsCopy = CT == Ctor_CopyingClosure;
3365 CodeGenFunction CGF(CGM);
3366 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3368 // Build FunctionArgs.
3369 FunctionArgList FunctionArgs;
3371 // A constructor always starts with a 'this' pointer as its first argument.
3372 buildThisParam(CGF, FunctionArgs);
3374 // Following the 'this' pointer is a reference to the source object that we
3375 // are copying from.
3376 ImplicitParamDecl SrcParam(
3377 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3378 getContext().getLValueReferenceType(RecordTy,
3379 /*SpelledAsLValue=*/true));
3381 FunctionArgs.push_back(&SrcParam);
3383 // Constructors for classes which utilize virtual bases have an additional
3384 // parameter which indicates whether or not it is being delegated to by a more
3385 // derived constructor.
3386 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3387 &getContext().Idents.get("is_most_derived"),
3388 getContext().IntTy);
3389 // Only add the parameter to the list if thie class has virtual bases.
3390 if (RD->getNumVBases() > 0)
3391 FunctionArgs.push_back(&IsMostDerived);
3393 // Start defining the function.
3394 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3395 FunctionArgs, CD->getLocation(), SourceLocation());
3397 llvm::Value *This = getThisValue(CGF);
3399 llvm::Value *SrcVal =
3400 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3405 // Push the this ptr.
3406 Args.add(RValue::get(This), CD->getThisType(getContext()));
3408 // Push the src ptr.
3410 Args.add(RValue::get(SrcVal), SrcParam.getType());
3412 // Add the rest of the default arguments.
3413 std::vector<Stmt *> ArgVec;
3414 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I)
3415 ArgVec.push_back(getContext().getDefaultArgExprForConstructor(CD, I));
3417 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3419 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3420 ConstExprIterator ArgBegin(ArgVec.data()),
3421 ArgEnd(ArgVec.data() + ArgVec.size());
3422 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3424 // Insert any ABI-specific implicit constructor arguments.
3425 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3426 /*ForVirtualBase=*/false,
3427 /*Delegating=*/false, Args);
3429 // Call the destructor with our arguments.
3430 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3431 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3432 Args, CD, Ctor_Complete, ExtraArgs);
3433 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3435 Cleanups.ForceCleanup();
3437 // Emit the ret instruction, remove any temporary instructions created for the
3439 CGF.FinishFunction(SourceLocation());
3444 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3446 int32_t VBPtrOffset,
3448 assert(!T->isReferenceType());
3450 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3451 const CXXConstructorDecl *CD =
3452 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3453 CXXCtorType CT = Ctor_Complete;
3455 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3456 CT = Ctor_CopyingClosure;
3458 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3459 SmallString<256> MangledName;
3461 llvm::raw_svector_ostream Out(MangledName);
3462 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3463 VBPtrOffset, VBIndex, Out);
3465 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3466 return getImageRelativeConstant(GV);
3468 // The TypeDescriptor is used by the runtime to determine if a catch handler
3469 // is appropriate for the exception object.
3470 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3472 // The runtime is responsible for calling the copy constructor if the
3473 // exception is caught by value.
3474 llvm::Constant *CopyCtor;
3476 if (CT == Ctor_CopyingClosure)
3477 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3479 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3481 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3483 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3485 CopyCtor = getImageRelativeConstant(CopyCtor);
3487 bool IsScalar = !RD;
3488 bool HasVirtualBases = false;
3489 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3490 QualType PointeeType = T;
3491 if (T->isPointerType())
3492 PointeeType = T->getPointeeType();
3493 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3494 HasVirtualBases = RD->getNumVBases() > 0;
3495 if (IdentifierInfo *II = RD->getIdentifier())
3496 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3499 // Encode the relevant CatchableType properties into the Flags bitfield.
3500 // FIXME: Figure out how bits 2 or 8 can get set.
3504 if (HasVirtualBases)
3509 llvm::Constant *Fields[] = {
3510 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3511 TD, // TypeDescriptor
3512 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3513 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3514 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3515 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3516 CopyCtor // CopyCtor
3518 llvm::StructType *CTType = getCatchableTypeType();
3519 auto *GV = new llvm::GlobalVariable(
3520 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3521 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3522 GV->setUnnamedAddr(true);
3523 GV->setSection(".xdata");
3524 if (GV->isWeakForLinker())
3525 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3526 return getImageRelativeConstant(GV);
3529 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3530 assert(!T->isReferenceType());
3532 // See if we've already generated a CatchableTypeArray for this type before.
3533 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3537 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3538 // using a SmallSetVector. Duplicates may arise due to virtual bases
3539 // occurring more than once in the hierarchy.
3540 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3542 // C++14 [except.handle]p3:
3543 // A handler is a match for an exception object of type E if [...]
3544 // - the handler is of type cv T or cv T& and T is an unambiguous public
3545 // base class of E, or
3546 // - the handler is of type cv T or const T& where T is a pointer type and
3547 // E is a pointer type that can be converted to T by [...]
3548 // - a standard pointer conversion (4.10) not involving conversions to
3549 // pointers to private or protected or ambiguous classes
3550 const CXXRecordDecl *MostDerivedClass = nullptr;
3551 bool IsPointer = T->isPointerType();
3553 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3555 MostDerivedClass = T->getAsCXXRecordDecl();
3557 // Collect all the unambiguous public bases of the MostDerivedClass.
3558 if (MostDerivedClass) {
3559 const ASTContext &Context = getContext();
3560 const ASTRecordLayout &MostDerivedLayout =
3561 Context.getASTRecordLayout(MostDerivedClass);
3562 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3563 SmallVector<MSRTTIClass, 8> Classes;
3564 serializeClassHierarchy(Classes, MostDerivedClass);
3565 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3566 detectAmbiguousBases(Classes);
3567 for (const MSRTTIClass &Class : Classes) {
3568 // Skip any ambiguous or private bases.
3570 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3572 // Write down how to convert from a derived pointer to a base pointer.
3573 uint32_t OffsetInVBTable = 0;
3574 int32_t VBPtrOffset = -1;
3575 if (Class.VirtualRoot) {
3577 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3578 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3581 // Turn our record back into a pointer if the exception object is a
3583 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3585 RTTITy = Context.getPointerType(RTTITy);
3586 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3587 VBPtrOffset, OffsetInVBTable));
3591 // C++14 [except.handle]p3:
3592 // A handler is a match for an exception object of type E if
3593 // - The handler is of type cv T or cv T& and E and T are the same type
3594 // (ignoring the top-level cv-qualifiers)
3595 CatchableTypes.insert(getCatchableType(T));
3597 // C++14 [except.handle]p3:
3598 // A handler is a match for an exception object of type E if
3599 // - the handler is of type cv T or const T& where T is a pointer type and
3600 // E is a pointer type that can be converted to T by [...]
3601 // - a standard pointer conversion (4.10) not involving conversions to
3602 // pointers to private or protected or ambiguous classes
3604 // All pointers are convertible to pointer-to-void so ensure that it is in the
3605 // CatchableTypeArray.
3607 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3609 // C++14 [except.handle]p3:
3610 // A handler is a match for an exception object of type E if [...]
3611 // - the handler is of type cv T or const T& where T is a pointer or
3612 // pointer to member type and E is std::nullptr_t.
3614 // We cannot possibly list all possible pointer types here, making this
3615 // implementation incompatible with the standard. However, MSVC includes an
3616 // entry for pointer-to-void in this case. Let's do the same.
3617 if (T->isNullPtrType())
3618 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3620 uint32_t NumEntries = CatchableTypes.size();
3621 llvm::Type *CTType =
3622 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3623 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3624 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3625 llvm::Constant *Fields[] = {
3626 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3627 llvm::ConstantArray::get(
3628 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3629 CatchableTypes.end())) // CatchableTypes
3631 SmallString<256> MangledName;
3633 llvm::raw_svector_ostream Out(MangledName);
3634 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3636 CTA = new llvm::GlobalVariable(
3637 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3638 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3639 CTA->setUnnamedAddr(true);
3640 CTA->setSection(".xdata");
3641 if (CTA->isWeakForLinker())
3642 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3646 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3647 bool IsConst, IsVolatile;
3648 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
3650 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3651 // the exception object may be caught as.
3652 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3653 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3654 // This is used as a component of the mangled name which means that we need to
3655 // know what it is in order to see if we have previously generated the
3657 uint32_t NumEntries =
3658 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3659 ->getLimitedValue();
3661 SmallString<256> MangledName;
3663 llvm::raw_svector_ostream Out(MangledName);
3664 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3668 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3670 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3673 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3674 // be at least as CV qualified. Encode this requirement into the Flags
3682 // The cleanup-function (a destructor) must be called when the exception
3683 // object's lifetime ends.
3684 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3685 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3686 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3687 if (!DtorD->isTrivial())
3688 CleanupFn = llvm::ConstantExpr::getBitCast(
3689 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3691 // This is unused as far as we can tell, initialize it to null.
3692 llvm::Constant *ForwardCompat =
3693 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3694 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3695 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3696 llvm::StructType *TIType = getThrowInfoType();
3697 llvm::Constant *Fields[] = {
3698 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3699 getImageRelativeConstant(CleanupFn), // CleanupFn
3700 ForwardCompat, // ForwardCompat
3701 PointerToCatchableTypes // CatchableTypeArray
3703 auto *GV = new llvm::GlobalVariable(
3704 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3705 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3706 GV->setUnnamedAddr(true);
3707 GV->setSection(".xdata");
3708 if (GV->isWeakForLinker())
3709 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3713 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3714 const Expr *SubExpr = E->getSubExpr();
3715 QualType ThrowType = SubExpr->getType();
3716 // The exception object lives on the stack and it's address is passed to the
3717 // runtime function.
3718 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
3719 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
3722 // The so-called ThrowInfo is used to describe how the exception object may be
3724 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
3726 // Call into the runtime to throw the exception.
3727 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
3728 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);