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), CatchHandlerTypeType(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 getAddrOfCXXCatchHandlerType(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 emitVTableBitSetEntries(VPtrInfo *Info, const CXXRecordDecl *RD,
209 llvm::GlobalVariable *VTable);
211 void emitVTableDefinitions(CodeGenVTables &CGVT,
212 const CXXRecordDecl *RD) override;
214 llvm::Value *getVTableAddressPointInStructor(
215 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
216 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
217 bool &NeedsVirtualOffset) override;
220 getVTableAddressPointForConstExpr(BaseSubobject Base,
221 const CXXRecordDecl *VTableClass) override;
223 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
224 CharUnits VPtrOffset) override;
226 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
227 llvm::Value *This, llvm::Type *Ty,
228 SourceLocation Loc) override;
230 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
231 const CXXDestructorDecl *Dtor,
232 CXXDtorType DtorType,
234 const CXXMemberCallExpr *CE) override;
236 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
237 CallArgList &CallArgs) override {
238 assert(GD.getDtorType() == Dtor_Deleting &&
239 "Only deleting destructor thunks are available in this ABI");
240 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
244 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
246 llvm::GlobalVariable *
247 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
248 llvm::GlobalVariable::LinkageTypes Linkage);
250 llvm::GlobalVariable *
251 getAddrOfVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
252 const CXXRecordDecl *DstRD) {
253 SmallString<256> OutName;
254 llvm::raw_svector_ostream Out(OutName);
255 getMangleContext().mangleCXXVirtualDisplacementMap(SrcRD, DstRD, Out);
257 StringRef MangledName = OutName.str();
259 if (auto *VDispMap = CGM.getModule().getNamedGlobal(MangledName))
262 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
263 unsigned NumEntries = 1 + SrcRD->getNumVBases();
264 SmallVector<llvm::Constant *, 4> Map(NumEntries,
265 llvm::UndefValue::get(CGM.IntTy));
266 Map[0] = llvm::ConstantInt::get(CGM.IntTy, 0);
267 bool AnyDifferent = false;
268 for (const auto &I : SrcRD->vbases()) {
269 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
270 if (!DstRD->isVirtuallyDerivedFrom(VBase))
273 unsigned SrcVBIndex = VTContext.getVBTableIndex(SrcRD, VBase);
274 unsigned DstVBIndex = VTContext.getVBTableIndex(DstRD, VBase);
275 Map[SrcVBIndex] = llvm::ConstantInt::get(CGM.IntTy, DstVBIndex * 4);
276 AnyDifferent |= SrcVBIndex != DstVBIndex;
278 // This map would be useless, don't use it.
282 llvm::ArrayType *VDispMapTy = llvm::ArrayType::get(CGM.IntTy, Map.size());
283 llvm::Constant *Init = llvm::ConstantArray::get(VDispMapTy, Map);
284 llvm::GlobalValue::LinkageTypes Linkage =
285 SrcRD->isExternallyVisible() && DstRD->isExternallyVisible()
286 ? llvm::GlobalValue::LinkOnceODRLinkage
287 : llvm::GlobalValue::InternalLinkage;
288 auto *VDispMap = new llvm::GlobalVariable(
289 CGM.getModule(), VDispMapTy, /*Constant=*/true, Linkage,
290 /*Initializer=*/Init, MangledName);
294 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
295 llvm::GlobalVariable *GV) const;
297 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
298 GlobalDecl GD, bool ReturnAdjustment) override {
299 // Never dllimport/dllexport thunks.
300 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
303 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
305 if (Linkage == GVA_Internal)
306 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
307 else if (ReturnAdjustment)
308 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
310 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
313 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
314 const ThisAdjustment &TA) override;
316 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
317 const ReturnAdjustment &RA) override;
319 void EmitThreadLocalInitFuncs(
321 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
323 ArrayRef<llvm::Function *> CXXThreadLocalInits,
324 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
326 bool usesThreadWrapperFunction() const override { return false; }
327 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
328 QualType LValType) override;
330 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
331 llvm::GlobalVariable *DeclPtr,
332 bool PerformInit) override;
333 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
334 llvm::Constant *Dtor, llvm::Constant *Addr) override;
336 // ==== Notes on array cookies =========
338 // MSVC seems to only use cookies when the class has a destructor; a
339 // two-argument usual array deallocation function isn't sufficient.
341 // For example, this code prints "100" and "1":
344 // void *operator new[](size_t sz) {
345 // printf("%u\n", sz);
346 // return malloc(sz);
348 // void operator delete[](void *p, size_t sz) {
349 // printf("%u\n", sz);
354 // A *p = new A[100];
357 // Whereas it prints "104" and "104" if you give A a destructor.
359 bool requiresArrayCookie(const CXXDeleteExpr *expr,
360 QualType elementType) override;
361 bool requiresArrayCookie(const CXXNewExpr *expr) override;
362 CharUnits getArrayCookieSizeImpl(QualType type) override;
363 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
365 llvm::Value *NumElements,
366 const CXXNewExpr *expr,
367 QualType ElementType) override;
368 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
369 llvm::Value *allocPtr,
370 CharUnits cookieSize) override;
372 friend struct MSRTTIBuilder;
374 bool isImageRelative() const {
375 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
378 // 5 routines for constructing the llvm types for MS RTTI structs.
379 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
380 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
381 TDTypeName += llvm::utostr(TypeInfoString.size());
382 llvm::StructType *&TypeDescriptorType =
383 TypeDescriptorTypeMap[TypeInfoString.size()];
384 if (TypeDescriptorType)
385 return TypeDescriptorType;
386 llvm::Type *FieldTypes[] = {
389 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
391 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
392 return TypeDescriptorType;
395 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
396 if (!isImageRelative())
401 llvm::StructType *getBaseClassDescriptorType() {
402 if (BaseClassDescriptorType)
403 return BaseClassDescriptorType;
404 llvm::Type *FieldTypes[] = {
405 getImageRelativeType(CGM.Int8PtrTy),
411 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
413 BaseClassDescriptorType = llvm::StructType::create(
414 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
415 return BaseClassDescriptorType;
418 llvm::StructType *getClassHierarchyDescriptorType() {
419 if (ClassHierarchyDescriptorType)
420 return ClassHierarchyDescriptorType;
421 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
422 ClassHierarchyDescriptorType = llvm::StructType::create(
423 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
424 llvm::Type *FieldTypes[] = {
428 getImageRelativeType(
429 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
431 ClassHierarchyDescriptorType->setBody(FieldTypes);
432 return ClassHierarchyDescriptorType;
435 llvm::StructType *getCompleteObjectLocatorType() {
436 if (CompleteObjectLocatorType)
437 return CompleteObjectLocatorType;
438 CompleteObjectLocatorType = llvm::StructType::create(
439 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
440 llvm::Type *FieldTypes[] = {
444 getImageRelativeType(CGM.Int8PtrTy),
445 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
446 getImageRelativeType(CompleteObjectLocatorType),
448 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
449 if (!isImageRelative())
450 FieldTypesRef = FieldTypesRef.drop_back();
451 CompleteObjectLocatorType->setBody(FieldTypesRef);
452 return CompleteObjectLocatorType;
455 llvm::GlobalVariable *getImageBase() {
456 StringRef Name = "__ImageBase";
457 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
460 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
462 llvm::GlobalValue::ExternalLinkage,
463 /*Initializer=*/nullptr, Name);
466 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
467 if (!isImageRelative())
470 if (PtrVal->isNullValue())
471 return llvm::Constant::getNullValue(CGM.IntTy);
473 llvm::Constant *ImageBaseAsInt =
474 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
475 llvm::Constant *PtrValAsInt =
476 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
477 llvm::Constant *Diff =
478 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
479 /*HasNUW=*/true, /*HasNSW=*/true);
480 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
484 MicrosoftMangleContext &getMangleContext() {
485 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
488 llvm::Constant *getZeroInt() {
489 return llvm::ConstantInt::get(CGM.IntTy, 0);
492 llvm::Constant *getAllOnesInt() {
493 return llvm::Constant::getAllOnesValue(CGM.IntTy);
496 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
497 return C ? C : getZeroInt();
500 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
501 return C ? C : getZeroInt();
504 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
507 GetNullMemberPointerFields(const MemberPointerType *MPT,
508 llvm::SmallVectorImpl<llvm::Constant *> &fields);
510 /// \brief Shared code for virtual base adjustment. Returns the offset from
511 /// the vbptr to the virtual base. Optionally returns the address of the
513 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
515 llvm::Value *VBPtrOffset,
516 llvm::Value *VBTableOffset,
517 llvm::Value **VBPtr = nullptr);
519 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
522 int32_t VBTableOffset,
523 llvm::Value **VBPtr = nullptr) {
524 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
525 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
526 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
527 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
530 std::pair<llvm::Value *, llvm::Value *>
531 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
532 QualType SrcRecordTy);
534 /// \brief Performs a full virtual base adjustment. Used to dereference
535 /// pointers to members of virtual bases.
536 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
537 const CXXRecordDecl *RD, llvm::Value *Base,
538 llvm::Value *VirtualBaseAdjustmentOffset,
539 llvm::Value *VBPtrOffset /* optional */);
541 /// \brief Emits a full member pointer with the fields common to data and
542 /// function member pointers.
543 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
544 bool IsMemberFunction,
545 const CXXRecordDecl *RD,
546 CharUnits NonVirtualBaseAdjustment,
547 unsigned VBTableIndex);
549 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
552 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
553 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
555 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
556 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
558 /// \brief Generate a thunk for calling a virtual member function MD.
559 llvm::Function *EmitVirtualMemPtrThunk(
560 const CXXMethodDecl *MD,
561 const MicrosoftVTableContext::MethodVFTableLocation &ML);
564 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
566 bool isZeroInitializable(const MemberPointerType *MPT) override;
568 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
569 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
570 return RD->hasAttr<MSInheritanceAttr>();
573 bool isTypeInfoCalculable(QualType Ty) const override {
574 if (!CGCXXABI::isTypeInfoCalculable(Ty))
576 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
577 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
578 if (!RD->hasAttr<MSInheritanceAttr>())
584 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
586 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
587 CharUnits offset) override;
588 llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override;
589 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
591 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
594 const MemberPointerType *MPT,
595 bool Inequality) override;
597 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
599 const MemberPointerType *MPT) override;
602 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
603 llvm::Value *Base, llvm::Value *MemPtr,
604 const MemberPointerType *MPT) override;
606 llvm::Value *EmitNonNullMemberPointerConversion(
607 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
608 CastKind CK, CastExpr::path_const_iterator PathBegin,
609 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
610 CGBuilderTy &Builder);
612 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
614 llvm::Value *Src) override;
616 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
617 llvm::Constant *Src) override;
619 llvm::Constant *EmitMemberPointerConversion(
620 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
621 CastKind CK, CastExpr::path_const_iterator PathBegin,
622 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
625 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
626 llvm::Value *&This, llvm::Value *MemPtr,
627 const MemberPointerType *MPT) override;
629 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
631 llvm::StructType *getCatchHandlerTypeType() {
632 if (!CatchHandlerTypeType) {
633 llvm::Type *FieldTypes[] = {
635 CGM.Int8PtrTy, // TypeDescriptor
637 CatchHandlerTypeType = llvm::StructType::create(
638 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
640 return CatchHandlerTypeType;
643 llvm::StructType *getCatchableTypeType() {
644 if (CatchableTypeType)
645 return CatchableTypeType;
646 llvm::Type *FieldTypes[] = {
648 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
649 CGM.IntTy, // NonVirtualAdjustment
650 CGM.IntTy, // OffsetToVBPtr
651 CGM.IntTy, // VBTableIndex
653 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
655 CatchableTypeType = llvm::StructType::create(
656 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
657 return CatchableTypeType;
660 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
661 llvm::StructType *&CatchableTypeArrayType =
662 CatchableTypeArrayTypeMap[NumEntries];
663 if (CatchableTypeArrayType)
664 return CatchableTypeArrayType;
666 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
667 CTATypeName += llvm::utostr(NumEntries);
669 getImageRelativeType(getCatchableTypeType()->getPointerTo());
670 llvm::Type *FieldTypes[] = {
671 CGM.IntTy, // NumEntries
672 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
674 CatchableTypeArrayType =
675 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
676 return CatchableTypeArrayType;
679 llvm::StructType *getThrowInfoType() {
681 return ThrowInfoType;
682 llvm::Type *FieldTypes[] = {
684 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
685 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
686 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
688 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
690 return ThrowInfoType;
693 llvm::Constant *getThrowFn() {
694 // _CxxThrowException is passed an exception object and a ThrowInfo object
695 // which describes the exception.
696 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
697 llvm::FunctionType *FTy =
698 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
699 auto *Fn = cast<llvm::Function>(
700 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
701 // _CxxThrowException is stdcall on 32-bit x86 platforms.
702 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
703 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
707 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
710 llvm::Constant *getCatchableType(QualType T,
711 uint32_t NVOffset = 0,
712 int32_t VBPtrOffset = -1,
713 uint32_t VBIndex = 0);
715 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
717 llvm::GlobalVariable *getThrowInfo(QualType T) override;
720 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
721 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
722 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
723 /// \brief All the vftables that have been referenced.
724 VFTablesMapTy VFTablesMap;
725 VTablesMapTy VTablesMap;
727 /// \brief This set holds the record decls we've deferred vtable emission for.
728 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
731 /// \brief All the vbtables which have been referenced.
732 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
734 /// Info on the global variable used to guard initialization of static locals.
735 /// The BitIndex field is only used for externally invisible declarations.
737 GuardInfo() : Guard(nullptr), BitIndex(0) {}
738 llvm::GlobalVariable *Guard;
742 /// Map from DeclContext to the current guard variable. We assume that the
743 /// AST is visited in source code order.
744 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
745 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
746 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
748 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
749 llvm::StructType *BaseClassDescriptorType;
750 llvm::StructType *ClassHierarchyDescriptorType;
751 llvm::StructType *CompleteObjectLocatorType;
753 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
755 llvm::StructType *CatchableTypeType;
756 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
757 llvm::StructType *ThrowInfoType;
758 llvm::StructType *CatchHandlerTypeType;
763 CGCXXABI::RecordArgABI
764 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
765 switch (CGM.getTarget().getTriple().getArch()) {
767 // FIXME: Implement for other architectures.
770 case llvm::Triple::x86:
771 // All record arguments are passed in memory on x86. Decide whether to
772 // construct the object directly in argument memory, or to construct the
773 // argument elsewhere and copy the bytes during the call.
775 // If C++ prohibits us from making a copy, construct the arguments directly
776 // into argument memory.
777 if (!canCopyArgument(RD))
778 return RAA_DirectInMemory;
780 // Otherwise, construct the argument into a temporary and copy the bytes
781 // into the outgoing argument memory.
784 case llvm::Triple::x86_64:
785 // Win64 passes objects with non-trivial copy ctors indirectly.
786 if (RD->hasNonTrivialCopyConstructor())
789 // If an object has a destructor, we'd really like to pass it indirectly
790 // because it allows us to elide copies. Unfortunately, MSVC makes that
791 // impossible for small types, which it will pass in a single register or
792 // stack slot. Most objects with dtors are large-ish, so handle that early.
793 // We can't call out all large objects as being indirect because there are
794 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
795 // how we pass large POD types.
796 if (RD->hasNonTrivialDestructor() &&
797 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
800 // We have a trivial copy constructor or no copy constructors, but we have
801 // to make sure it isn't deleted.
802 bool CopyDeleted = false;
803 for (const CXXConstructorDecl *CD : RD->ctors()) {
804 if (CD->isCopyConstructor()) {
805 assert(CD->isTrivial());
806 // We had at least one undeleted trivial copy ctor. Return directly.
807 if (!CD->isDeleted())
813 // The trivial copy constructor was deleted. Return indirectly.
817 // There were no copy ctors. Return in RAX.
821 llvm_unreachable("invalid enum");
824 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
825 const CXXDeleteExpr *DE,
827 QualType ElementType,
828 const CXXDestructorDecl *Dtor) {
829 // FIXME: Provide a source location here even though there's no
830 // CXXMemberCallExpr for dtor call.
831 bool UseGlobalDelete = DE->isGlobalDelete();
832 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
833 llvm::Value *MDThis =
834 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
836 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
839 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
840 llvm::Value *Args[] = {
841 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
842 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
843 auto *Fn = getThrowFn();
845 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
847 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
851 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
852 CallEndCatchMSVC() {}
853 void Emit(CodeGenFunction &CGF, Flags flags) override {
854 CGF.EmitNounwindRuntimeCall(
855 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
860 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
861 const CXXCatchStmt *S) {
862 // In the MS ABI, the runtime handles the copy, and the catch handler is
863 // responsible for destruction.
864 VarDecl *CatchParam = S->getExceptionDecl();
865 llvm::Value *Exn = CGF.getExceptionFromSlot();
866 llvm::Function *BeginCatch =
867 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
869 // If this is a catch-all or the catch parameter is unnamed, we don't need to
870 // emit an alloca to the object.
871 if (!CatchParam || !CatchParam->getDeclName()) {
872 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
873 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
874 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
878 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
879 llvm::Value *ParamAddr =
880 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
881 llvm::Value *Args[2] = {Exn, ParamAddr};
882 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
883 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
884 CGF.EmitAutoVarCleanups(var);
887 std::pair<llvm::Value *, llvm::Value *>
888 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
889 QualType SrcRecordTy) {
890 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
891 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
892 const ASTContext &Context = getContext();
894 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
895 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
897 // Perform a base adjustment.
898 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
899 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
900 [&](const CXXBaseSpecifier &Base) {
901 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
902 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
904 llvm::Value *Offset = GetVirtualBaseClassOffset(
905 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
906 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
907 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
908 return std::make_pair(Value, Offset);
911 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
912 QualType SrcRecordTy) {
913 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
915 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
918 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
919 llvm::Value *Argument) {
920 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
921 llvm::FunctionType *FTy =
922 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
923 llvm::Value *Args[] = {Argument};
924 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
925 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
928 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
929 llvm::CallSite Call =
930 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
931 Call.setDoesNotReturn();
932 CGF.Builder.CreateUnreachable();
935 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
936 QualType SrcRecordTy,
937 llvm::Value *ThisPtr,
938 llvm::Type *StdTypeInfoPtrTy) {
940 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
941 return CGF.Builder.CreateBitCast(
942 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
945 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
946 QualType SrcRecordTy) {
947 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
949 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
952 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
953 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
954 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
955 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
957 llvm::Value *SrcRTTI =
958 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
959 llvm::Value *DestRTTI =
960 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
963 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
965 // PVOID __RTDynamicCast(
971 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
972 CGF.Int8PtrTy, CGF.Int32Ty};
973 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
974 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
976 llvm::Value *Args[] = {
977 Value, Offset, SrcRTTI, DestRTTI,
978 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
979 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
980 return CGF.Builder.CreateBitCast(Value, DestLTy);
984 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
985 QualType SrcRecordTy,
988 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
990 // PVOID __RTCastToVoid(
992 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
993 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
994 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
996 llvm::Value *Args[] = {Value};
997 return CGF.EmitRuntimeCall(Function, Args);
1000 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
1004 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
1005 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
1006 const CXXRecordDecl *BaseClassDecl) {
1007 const ASTContext &Context = getContext();
1008 int64_t VBPtrChars =
1009 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
1010 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
1011 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
1012 CharUnits VBTableChars =
1014 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
1015 llvm::Value *VBTableOffset =
1016 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
1018 llvm::Value *VBPtrToNewBase =
1019 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
1021 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
1022 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
1025 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
1026 return isa<CXXConstructorDecl>(GD.getDecl());
1029 static bool isDeletingDtor(GlobalDecl GD) {
1030 return isa<CXXDestructorDecl>(GD.getDecl()) &&
1031 GD.getDtorType() == Dtor_Deleting;
1034 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
1035 return isDeletingDtor(GD);
1038 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
1039 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
1043 if (FI.isInstanceMethod()) {
1044 // If it's an instance method, aggregates are always returned indirectly via
1045 // the second parameter.
1046 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1047 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
1049 } else if (!RD->isPOD()) {
1050 // If it's a free function, non-POD types are returned indirectly.
1051 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1055 // Otherwise, use the C ABI rules.
1060 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1061 const CXXRecordDecl *RD) {
1062 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1063 assert(IsMostDerivedClass &&
1064 "ctor for a class with virtual bases must have an implicit parameter");
1065 llvm::Value *IsCompleteObject =
1066 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1068 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1069 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1070 CGF.Builder.CreateCondBr(IsCompleteObject,
1071 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1073 CGF.EmitBlock(CallVbaseCtorsBB);
1075 // Fill in the vbtable pointers here.
1076 EmitVBPtrStores(CGF, RD);
1078 // CGF will put the base ctor calls in this basic block for us later.
1080 return SkipVbaseCtorsBB;
1083 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1084 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1085 // In most cases, an override for a vbase virtual method can adjust
1086 // the "this" parameter by applying a constant offset.
1087 // However, this is not enough while a constructor or a destructor of some
1088 // class X is being executed if all the following conditions are met:
1089 // - X has virtual bases, (1)
1090 // - X overrides a virtual method M of a vbase Y, (2)
1091 // - X itself is a vbase of the most derived class.
1093 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1094 // which holds the extra amount of "this" adjustment we must do when we use
1095 // the X vftables (i.e. during X ctor or dtor).
1096 // Outside the ctors and dtors, the values of vtorDisps are zero.
1098 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1099 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1100 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1101 CGBuilderTy &Builder = CGF.Builder;
1104 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1105 llvm::Value *Int8This = nullptr; // Initialize lazily.
1107 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1109 if (!I->second.hasVtorDisp())
1112 llvm::Value *VBaseOffset =
1113 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1114 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1115 // just to Trunc back immediately.
1116 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1117 uint64_t ConstantVBaseOffset =
1118 Layout.getVBaseClassOffset(I->first).getQuantity();
1120 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1121 llvm::Value *VtorDispValue = Builder.CreateSub(
1122 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1126 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1127 CGF.Int8Ty->getPointerTo(AS));
1128 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1129 // vtorDisp is always the 32-bits before the vbase in the class layout.
1130 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1131 VtorDispPtr = Builder.CreateBitCast(
1132 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1134 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1138 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1139 const CXXMethodDecl *MD) {
1140 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1141 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1142 CallingConv ActualCallingConv =
1143 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1144 return ExpectedCallingConv == ActualCallingConv;
1147 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1148 // There's only one constructor type in this ABI.
1149 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1151 // Exported default constructors either have a simple call-site where they use
1152 // the typical calling convention and have a single 'this' pointer for an
1153 // argument -or- they get a wrapper function which appropriately thunks to the
1154 // real default constructor. This thunk is the default constructor closure.
1155 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1156 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1157 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1158 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1159 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1163 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1164 const CXXRecordDecl *RD) {
1165 llvm::Value *ThisInt8Ptr =
1166 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1167 const ASTContext &Context = getContext();
1168 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1170 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1171 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1172 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1173 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1174 const ASTRecordLayout &SubobjectLayout =
1175 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1176 CharUnits Offs = VBT->NonVirtualOffset;
1177 Offs += SubobjectLayout.getVBPtrOffset();
1178 if (VBT->getVBaseWithVPtr())
1179 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1180 llvm::Value *VBPtr =
1181 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1182 llvm::Value *GVPtr =
1183 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1184 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1185 "vbptr." + VBT->ReusingBase->getName());
1186 CGF.Builder.CreateStore(GVPtr, VBPtr);
1191 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1192 SmallVectorImpl<CanQualType> &ArgTys) {
1193 // TODO: 'for base' flag
1194 if (T == StructorType::Deleting) {
1195 // The scalar deleting destructor takes an implicit int parameter.
1196 ArgTys.push_back(getContext().IntTy);
1198 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1202 // All parameters are already in place except is_most_derived, which goes
1203 // after 'this' if it's variadic and last if it's not.
1205 const CXXRecordDecl *Class = CD->getParent();
1206 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1207 if (Class->getNumVBases()) {
1208 if (FPT->isVariadic())
1209 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1211 ArgTys.push_back(getContext().IntTy);
1215 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1216 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1217 // other destructor variants are delegating thunks.
1218 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1222 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1223 GD = GD.getCanonicalDecl();
1224 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1226 GlobalDecl LookupGD = GD;
1227 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1228 // Complete destructors take a pointer to the complete object as a
1229 // parameter, thus don't need this adjustment.
1230 if (GD.getDtorType() == Dtor_Complete)
1233 // There's no Dtor_Base in vftable but it shares the this adjustment with
1234 // the deleting one, so look it up instead.
1235 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1238 MicrosoftVTableContext::MethodVFTableLocation ML =
1239 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1240 CharUnits Adjustment = ML.VFPtrOffset;
1242 // Normal virtual instance methods need to adjust from the vfptr that first
1243 // defined the virtual method to the virtual base subobject, but destructors
1244 // do not. The vector deleting destructor thunk applies this adjustment for
1246 if (isa<CXXDestructorDecl>(MD))
1247 Adjustment = CharUnits::Zero();
1250 const ASTRecordLayout &DerivedLayout =
1251 getContext().getASTRecordLayout(MD->getParent());
1252 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1258 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1259 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1261 // If the call of a virtual function is not virtual, we just have to
1262 // compensate for the adjustment the virtual function does in its prologue.
1263 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1264 if (Adjustment.isZero())
1267 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1268 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1269 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1270 assert(Adjustment.isPositive());
1271 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1274 GD = GD.getCanonicalDecl();
1275 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1277 GlobalDecl LookupGD = GD;
1278 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1279 // Complete dtors take a pointer to the complete object,
1280 // thus don't need adjustment.
1281 if (GD.getDtorType() == Dtor_Complete)
1284 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1285 // with the base one, so look up the deleting one instead.
1286 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1288 MicrosoftVTableContext::MethodVFTableLocation ML =
1289 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1291 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1292 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1293 CharUnits StaticOffset = ML.VFPtrOffset;
1295 // Base destructors expect 'this' to point to the beginning of the base
1296 // subobject, not the first vfptr that happens to contain the virtual dtor.
1297 // However, we still need to apply the virtual base adjustment.
1298 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1299 StaticOffset = CharUnits::Zero();
1302 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1303 llvm::Value *VBaseOffset =
1304 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1305 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1307 if (!StaticOffset.isZero()) {
1308 assert(StaticOffset.isPositive());
1309 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1311 // Non-virtual adjustment might result in a pointer outside the allocated
1312 // object, e.g. if the final overrider class is laid out after the virtual
1313 // base that declares a method in the most derived class.
1314 // FIXME: Update the code that emits this adjustment in thunks prologues.
1315 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1317 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1318 StaticOffset.getQuantity());
1324 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1326 FunctionArgList &Params) {
1327 ASTContext &Context = getContext();
1328 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1329 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1330 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1331 ImplicitParamDecl *IsMostDerived
1332 = ImplicitParamDecl::Create(Context, nullptr,
1333 CGF.CurGD.getDecl()->getLocation(),
1334 &Context.Idents.get("is_most_derived"),
1336 // The 'most_derived' parameter goes second if the ctor is variadic and last
1337 // if it's not. Dtors can't be variadic.
1338 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1339 if (FPT->isVariadic())
1340 Params.insert(Params.begin() + 1, IsMostDerived);
1342 Params.push_back(IsMostDerived);
1343 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1344 } else if (isDeletingDtor(CGF.CurGD)) {
1345 ImplicitParamDecl *ShouldDelete
1346 = ImplicitParamDecl::Create(Context, nullptr,
1347 CGF.CurGD.getDecl()->getLocation(),
1348 &Context.Idents.get("should_call_delete"),
1350 Params.push_back(ShouldDelete);
1351 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1355 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1356 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1357 // In this ABI, every virtual function takes a pointer to one of the
1358 // subobjects that first defines it as the 'this' parameter, rather than a
1359 // pointer to the final overrider subobject. Thus, we need to adjust it back
1360 // to the final overrider subobject before use.
1361 // See comments in the MicrosoftVFTableContext implementation for the details.
1362 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1363 if (Adjustment.isZero())
1366 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1367 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1368 *thisTy = This->getType();
1370 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1371 assert(Adjustment.isPositive());
1372 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1373 -Adjustment.getQuantity());
1374 return CGF.Builder.CreateBitCast(This, thisTy);
1377 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1380 /// If this is a function that the ABI specifies returns 'this', initialize
1381 /// the return slot to 'this' at the start of the function.
1383 /// Unlike the setting of return types, this is done within the ABI
1384 /// implementation instead of by clients of CGCXXABI because:
1385 /// 1) getThisValue is currently protected
1386 /// 2) in theory, an ABI could implement 'this' returns some other way;
1387 /// HasThisReturn only specifies a contract, not the implementation
1388 if (HasThisReturn(CGF.CurGD))
1389 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1390 else if (hasMostDerivedReturn(CGF.CurGD))
1391 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1394 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1395 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1396 assert(getStructorImplicitParamDecl(CGF) &&
1397 "no implicit parameter for a constructor with virtual bases?");
1398 getStructorImplicitParamValue(CGF)
1399 = CGF.Builder.CreateLoad(
1400 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1404 if (isDeletingDtor(CGF.CurGD)) {
1405 assert(getStructorImplicitParamDecl(CGF) &&
1406 "no implicit parameter for a deleting destructor?");
1407 getStructorImplicitParamValue(CGF)
1408 = CGF.Builder.CreateLoad(
1409 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1410 "should_call_delete");
1414 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1415 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1416 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1417 assert(Type == Ctor_Complete || Type == Ctor_Base);
1419 // Check if we need a 'most_derived' parameter.
1420 if (!D->getParent()->getNumVBases())
1423 // Add the 'most_derived' argument second if we are variadic or last if not.
1424 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1425 llvm::Value *MostDerivedArg =
1426 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1427 RValue RV = RValue::get(MostDerivedArg);
1428 if (MostDerivedArg) {
1429 if (FPT->isVariadic())
1430 Args.insert(Args.begin() + 1,
1431 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1433 Args.add(RV, getContext().IntTy);
1436 return 1; // Added one arg.
1439 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1440 const CXXDestructorDecl *DD,
1441 CXXDtorType Type, bool ForVirtualBase,
1442 bool Delegating, llvm::Value *This) {
1443 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1445 if (DD->isVirtual()) {
1446 assert(Type != CXXDtorType::Dtor_Deleting &&
1447 "The deleting destructor should only be called via a virtual call");
1448 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1452 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1453 /*ImplicitParam=*/nullptr,
1454 /*ImplicitParamTy=*/QualType(), nullptr,
1455 getFromDtorType(Type));
1458 void MicrosoftCXXABI::emitVTableBitSetEntries(VPtrInfo *Info,
1459 const CXXRecordDecl *RD,
1460 llvm::GlobalVariable *VTable) {
1461 if (!getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIVCall) &&
1462 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFINVCall) &&
1463 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIDerivedCast) &&
1464 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIUnrelatedCast))
1467 llvm::NamedMDNode *BitsetsMD =
1468 CGM.getModule().getOrInsertNamedMetadata("llvm.bitsets");
1470 // The location of the first virtual function pointer in the virtual table,
1471 // aka the "address point" on Itanium. This is at offset 0 if RTTI is
1472 // disabled, or sizeof(void*) if RTTI is enabled.
1473 CharUnits AddressPoint =
1474 getContext().getLangOpts().RTTIData
1475 ? getContext().toCharUnitsFromBits(
1476 getContext().getTargetInfo().getPointerWidth(0))
1477 : CharUnits::Zero();
1479 if (Info->PathToBaseWithVPtr.empty()) {
1480 if (!CGM.IsCFIBlacklistedRecord(RD))
1481 BitsetsMD->addOperand(
1482 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1486 // Add a bitset entry for the least derived base belonging to this vftable.
1487 if (!CGM.IsCFIBlacklistedRecord(Info->PathToBaseWithVPtr.back()))
1488 BitsetsMD->addOperand(CGM.CreateVTableBitSetEntry(
1489 VTable, AddressPoint, Info->PathToBaseWithVPtr.back()));
1491 // Add a bitset entry for each derived class that is laid out at the same
1492 // offset as the least derived base.
1493 for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) {
1494 const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1];
1495 const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I];
1497 const ASTRecordLayout &Layout =
1498 getContext().getASTRecordLayout(DerivedRD);
1500 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1501 if (VBI == Layout.getVBaseOffsetsMap().end())
1502 Offset = Layout.getBaseClassOffset(BaseRD);
1504 Offset = VBI->second.VBaseOffset;
1505 if (!Offset.isZero())
1507 if (!CGM.IsCFIBlacklistedRecord(DerivedRD))
1508 BitsetsMD->addOperand(
1509 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, DerivedRD));
1512 // Finally do the same for the most derived class.
1513 if (Info->FullOffsetInMDC.isZero() && !CGM.IsCFIBlacklistedRecord(RD))
1514 BitsetsMD->addOperand(
1515 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1518 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1519 const CXXRecordDecl *RD) {
1520 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1521 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1523 for (VPtrInfo *Info : VFPtrs) {
1524 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1525 if (VTable->hasInitializer())
1528 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1529 ? getMSCompleteObjectLocator(RD, Info)
1532 const VTableLayout &VTLayout =
1533 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1534 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1535 RD, VTLayout.vtable_component_begin(),
1536 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1537 VTLayout.getNumVTableThunks(), RTTI);
1539 VTable->setInitializer(Init);
1541 emitVTableBitSetEntries(Info, RD, VTable);
1545 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1546 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1547 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1548 NeedsVirtualOffset = (NearestVBase != nullptr);
1550 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1551 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1552 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1553 if (!VTableAddressPoint) {
1554 assert(Base.getBase()->getNumVBases() &&
1555 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1557 return VTableAddressPoint;
1560 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1561 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1562 SmallString<256> &Name) {
1563 llvm::raw_svector_ostream Out(Name);
1564 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1567 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1568 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1569 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1570 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1571 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1572 assert(VFTable && "Couldn't find a vftable for the given base?");
1576 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1577 CharUnits VPtrOffset) {
1578 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1579 // shouldn't be used in the given record type. We want to cache this result in
1580 // VFTablesMap, thus a simple zero check is not sufficient.
1581 VFTableIdTy ID(RD, VPtrOffset);
1582 VTablesMapTy::iterator I;
1584 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1588 llvm::GlobalVariable *&VTable = I->second;
1590 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1591 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1593 if (DeferredVFTables.insert(RD).second) {
1594 // We haven't processed this record type before.
1595 // Queue up this v-table for possible deferred emission.
1596 CGM.addDeferredVTable(RD);
1599 // Create all the vftables at once in order to make sure each vftable has
1600 // a unique mangled name.
1601 llvm::StringSet<> ObservedMangledNames;
1602 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1603 SmallString<256> Name;
1604 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1605 if (!ObservedMangledNames.insert(Name.str()).second)
1606 llvm_unreachable("Already saw this mangling before?");
1611 VPtrInfo *const *VFPtrI =
1612 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1613 return VPI->FullOffsetInMDC == VPtrOffset;
1615 if (VFPtrI == VFPtrs.end()) {
1616 VFTablesMap[ID] = nullptr;
1619 VPtrInfo *VFPtr = *VFPtrI;
1621 SmallString<256> VFTableName;
1622 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1624 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1625 bool VFTableComesFromAnotherTU =
1626 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1627 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1628 bool VTableAliasIsRequred =
1629 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1631 if (llvm::GlobalValue *VFTable =
1632 CGM.getModule().getNamedGlobal(VFTableName)) {
1633 VFTablesMap[ID] = VFTable;
1634 return VTableAliasIsRequred
1635 ? cast<llvm::GlobalVariable>(
1636 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1637 : cast<llvm::GlobalVariable>(VFTable);
1640 uint64_t NumVTableSlots =
1641 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1642 .getNumVTableComponents();
1643 llvm::GlobalValue::LinkageTypes VTableLinkage =
1644 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1646 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1648 llvm::ArrayType *VTableType =
1649 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1651 // Create a backing variable for the contents of VTable. The VTable may
1652 // or may not include space for a pointer to RTTI data.
1653 llvm::GlobalValue *VFTable;
1654 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1655 /*isConstant=*/true, VTableLinkage,
1656 /*Initializer=*/nullptr, VTableName);
1657 VTable->setUnnamedAddr(true);
1659 llvm::Comdat *C = nullptr;
1660 if (!VFTableComesFromAnotherTU &&
1661 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1662 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1663 VTableAliasIsRequred)))
1664 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1666 // Only insert a pointer into the VFTable for RTTI data if we are not
1667 // importing it. We never reference the RTTI data directly so there is no
1668 // need to make room for it.
1669 if (VTableAliasIsRequred) {
1670 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1671 llvm::ConstantInt::get(CGM.IntTy, 1)};
1672 // Create a GEP which points just after the first entry in the VFTable,
1673 // this should be the location of the first virtual method.
1674 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1675 VTable->getValueType(), VTable, GEPIndices);
1676 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1677 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1679 C->setSelectionKind(llvm::Comdat::Largest);
1681 VFTable = llvm::GlobalAlias::create(
1682 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1683 VFTableName.str(), VTableGEP, &CGM.getModule());
1684 VFTable->setUnnamedAddr(true);
1686 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1687 // be referencing any RTTI data.
1688 // The GlobalVariable will end up being an appropriate definition of the
1693 VTable->setComdat(C);
1695 if (RD->hasAttr<DLLImportAttr>())
1696 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1697 else if (RD->hasAttr<DLLExportAttr>())
1698 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1700 VFTablesMap[ID] = VFTable;
1704 // Compute the identity of the most derived class whose virtual table is located
1705 // at the given offset into RD.
1706 static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx,
1707 const CXXRecordDecl *RD,
1709 if (Offset.isZero())
1712 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
1713 const CXXRecordDecl *MaxBase = nullptr;
1714 CharUnits MaxBaseOffset;
1715 for (auto &&B : RD->bases()) {
1716 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1717 CharUnits BaseOffset = Layout.getBaseClassOffset(Base);
1718 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1720 MaxBaseOffset = BaseOffset;
1723 for (auto &&B : RD->vbases()) {
1724 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1725 CharUnits BaseOffset = Layout.getVBaseClassOffset(Base);
1726 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1728 MaxBaseOffset = BaseOffset;
1732 return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset);
1735 // Compute the identity of the most derived class whose virtual table is located
1736 // at the MethodVFTableLocation ML.
1737 static const CXXRecordDecl *
1738 getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD,
1739 MicrosoftVTableContext::MethodVFTableLocation &ML) {
1740 const CXXRecordDecl *RD = ML.VBase;
1742 RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
1744 return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset);
1747 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1751 SourceLocation Loc) {
1752 GD = GD.getCanonicalDecl();
1753 CGBuilderTy &Builder = CGF.Builder;
1755 Ty = Ty->getPointerTo()->getPointerTo();
1757 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1758 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1760 MicrosoftVTableContext::MethodVFTableLocation ML =
1761 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1762 if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
1763 CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML),
1764 VTable, CodeGenFunction::CFITCK_VCall, Loc);
1766 llvm::Value *VFuncPtr =
1767 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1768 return Builder.CreateLoad(VFuncPtr);
1771 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1772 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1773 llvm::Value *This, const CXXMemberCallExpr *CE) {
1774 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1775 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1777 // We have only one destructor in the vftable but can get both behaviors
1778 // by passing an implicit int parameter.
1779 GlobalDecl GD(Dtor, Dtor_Deleting);
1780 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1781 Dtor, StructorType::Deleting);
1782 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1783 llvm::Value *Callee = getVirtualFunctionPointer(
1784 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1786 ASTContext &Context = getContext();
1787 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1788 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1789 DtorType == Dtor_Deleting);
1791 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1792 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1793 ImplicitParam, Context.IntTy, CE,
1794 StructorType::Deleting);
1795 return RV.getScalarVal();
1798 const VBTableGlobals &
1799 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1800 // At this layer, we can key the cache off of a single class, which is much
1801 // easier than caching each vbtable individually.
1802 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1804 std::tie(Entry, Added) =
1805 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1806 VBTableGlobals &VBGlobals = Entry->second;
1810 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1811 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1813 // Cache the globals for all vbtables so we don't have to recompute the
1815 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1816 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1817 E = VBGlobals.VBTables->end();
1819 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1825 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1826 const CXXMethodDecl *MD,
1827 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1828 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1829 "can't form pointers to ctors or virtual dtors");
1831 // Calculate the mangled name.
1832 SmallString<256> ThunkName;
1833 llvm::raw_svector_ostream Out(ThunkName);
1834 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1837 // If the thunk has been generated previously, just return it.
1838 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1839 return cast<llvm::Function>(GV);
1841 // Create the llvm::Function.
1842 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1843 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1844 llvm::Function *ThunkFn =
1845 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1846 ThunkName.str(), &CGM.getModule());
1847 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1849 ThunkFn->setLinkage(MD->isExternallyVisible()
1850 ? llvm::GlobalValue::LinkOnceODRLinkage
1851 : llvm::GlobalValue::InternalLinkage);
1852 if (MD->isExternallyVisible())
1853 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1855 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1856 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1858 // Add the "thunk" attribute so that LLVM knows that the return type is
1859 // meaningless. These thunks can be used to call functions with differing
1860 // return types, and the caller is required to cast the prototype
1861 // appropriately to extract the correct value.
1862 ThunkFn->addFnAttr("thunk");
1864 // These thunks can be compared, so they are not unnamed.
1865 ThunkFn->setUnnamedAddr(false);
1868 CodeGenFunction CGF(CGM);
1869 CGF.CurGD = GlobalDecl(MD);
1870 CGF.CurFuncIsThunk = true;
1872 // Build FunctionArgs, but only include the implicit 'this' parameter
1874 FunctionArgList FunctionArgs;
1875 buildThisParam(CGF, FunctionArgs);
1877 // Start defining the function.
1878 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1879 FunctionArgs, MD->getLocation(), SourceLocation());
1882 // Load the vfptr and then callee from the vftable. The callee should have
1883 // adjusted 'this' so that the vfptr is at offset zero.
1884 llvm::Value *VTable = CGF.GetVTablePtr(
1885 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1886 llvm::Value *VFuncPtr =
1887 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1888 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1890 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1895 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1896 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1897 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1898 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1899 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1900 if (GV->isDeclaration())
1901 emitVBTableDefinition(*VBT, RD, GV);
1905 llvm::GlobalVariable *
1906 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1907 llvm::GlobalVariable::LinkageTypes Linkage) {
1908 SmallString<256> OutName;
1909 llvm::raw_svector_ostream Out(OutName);
1910 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1912 StringRef Name = OutName.str();
1914 llvm::ArrayType *VBTableType =
1915 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1917 assert(!CGM.getModule().getNamedGlobal(Name) &&
1918 "vbtable with this name already exists: mangling bug?");
1919 llvm::GlobalVariable *GV =
1920 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1921 GV->setUnnamedAddr(true);
1923 if (RD->hasAttr<DLLImportAttr>())
1924 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1925 else if (RD->hasAttr<DLLExportAttr>())
1926 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1928 if (!GV->hasExternalLinkage())
1929 emitVBTableDefinition(VBT, RD, GV);
1934 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1935 const CXXRecordDecl *RD,
1936 llvm::GlobalVariable *GV) const {
1937 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1939 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1940 "should only emit vbtables for classes with vbtables");
1942 const ASTRecordLayout &BaseLayout =
1943 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1944 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1946 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1949 // The offset from ReusingBase's vbptr to itself always leads.
1950 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1951 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1953 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1954 for (const auto &I : ReusingBase->vbases()) {
1955 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1956 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1957 assert(!Offset.isNegative());
1959 // Make it relative to the subobject vbptr.
1960 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1961 if (VBT.getVBaseWithVPtr())
1962 CompleteVBPtrOffset +=
1963 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1964 Offset -= CompleteVBPtrOffset;
1966 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1967 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1968 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1971 assert(Offsets.size() ==
1972 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1973 ->getElementType())->getNumElements());
1974 llvm::ArrayType *VBTableType =
1975 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1976 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1977 GV->setInitializer(Init);
1980 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1982 const ThisAdjustment &TA) {
1986 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1988 if (!TA.Virtual.isEmpty()) {
1989 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1990 // Adjust the this argument based on the vtordisp value.
1991 llvm::Value *VtorDispPtr =
1992 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1994 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1995 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1996 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1998 if (TA.Virtual.Microsoft.VBPtrOffset) {
1999 // If the final overrider is defined in a virtual base other than the one
2000 // that holds the vfptr, we have to use a vtordispex thunk which looks up
2001 // the vbtable of the derived class.
2002 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
2003 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
2005 llvm::Value *VBaseOffset =
2006 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
2007 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
2008 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2012 if (TA.NonVirtual) {
2013 // Non-virtual adjustment might result in a pointer outside the allocated
2014 // object, e.g. if the final overrider class is laid out after the virtual
2015 // base that declares a method in the most derived class.
2016 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
2019 // Don't need to bitcast back, the call CodeGen will handle this.
2024 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
2025 const ReturnAdjustment &RA) {
2029 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
2031 if (RA.Virtual.Microsoft.VBIndex) {
2032 assert(RA.Virtual.Microsoft.VBIndex > 0);
2033 const ASTContext &Context = getContext();
2034 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
2036 llvm::Value *VBaseOffset =
2037 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
2038 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
2039 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2043 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
2045 // Cast back to the original type.
2046 return CGF.Builder.CreateBitCast(V, Ret->getType());
2049 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
2050 QualType elementType) {
2051 // Microsoft seems to completely ignore the possibility of a
2052 // two-argument usual deallocation function.
2053 return elementType.isDestructedType();
2056 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
2057 // Microsoft seems to completely ignore the possibility of a
2058 // two-argument usual deallocation function.
2059 return expr->getAllocatedType().isDestructedType();
2062 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2063 // The array cookie is always a size_t; we then pad that out to the
2064 // alignment of the element type.
2065 ASTContext &Ctx = getContext();
2066 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2067 Ctx.getTypeAlignInChars(type));
2070 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2071 llvm::Value *allocPtr,
2072 CharUnits cookieSize) {
2073 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
2074 llvm::Value *numElementsPtr =
2075 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
2076 return CGF.Builder.CreateLoad(numElementsPtr);
2079 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2080 llvm::Value *newPtr,
2081 llvm::Value *numElements,
2082 const CXXNewExpr *expr,
2083 QualType elementType) {
2084 assert(requiresArrayCookie(expr));
2086 // The size of the cookie.
2087 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2089 // Compute an offset to the cookie.
2090 llvm::Value *cookiePtr = newPtr;
2092 // Write the number of elements into the appropriate slot.
2093 unsigned AS = newPtr->getType()->getPointerAddressSpace();
2094 llvm::Value *numElementsPtr
2095 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
2096 CGF.Builder.CreateStore(numElements, numElementsPtr);
2098 // Finally, compute a pointer to the actual data buffer by skipping
2099 // over the cookie completely.
2100 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
2101 cookieSize.getQuantity());
2104 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2105 llvm::Constant *Dtor,
2106 llvm::Constant *Addr) {
2107 // Create a function which calls the destructor.
2108 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2110 // extern "C" int __tlregdtor(void (*f)(void));
2111 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2112 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2114 llvm::Constant *TLRegDtor =
2115 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
2116 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2117 TLRegDtorFn->setDoesNotThrow();
2119 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2122 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2123 llvm::Constant *Dtor,
2124 llvm::Constant *Addr) {
2126 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2128 // The default behavior is to use atexit.
2129 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2132 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2134 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
2136 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2137 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
2138 // This will create a GV in the .CRT$XDU section. It will point to our
2139 // initialization function. The CRT will call all of these function
2140 // pointers at start-up time and, eventually, at thread-creation time.
2141 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2142 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2143 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2144 llvm::GlobalVariable::InternalLinkage, InitFunc,
2145 Twine(InitFunc->getName(), "$initializer$"));
2146 InitFuncPtr->setSection(".CRT$XDU");
2147 // This variable has discardable linkage, we have to add it to @llvm.used to
2148 // ensure it won't get discarded.
2149 CGM.addUsedGlobal(InitFuncPtr);
2153 std::vector<llvm::Function *> NonComdatInits;
2154 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2155 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
2156 llvm::Function *F = CXXThreadLocalInits[I];
2158 // If the GV is already in a comdat group, then we have to join it.
2159 if (llvm::Comdat *C = GV->getComdat())
2160 AddToXDU(F)->setComdat(C);
2162 NonComdatInits.push_back(F);
2165 if (!NonComdatInits.empty()) {
2166 llvm::FunctionType *FTy =
2167 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2168 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2169 FTy, "__tls_init", SourceLocation(),
2171 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2177 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2179 QualType LValType) {
2180 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2184 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2185 StringRef VarName("_Init_thread_epoch");
2186 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2188 auto *GV = new llvm::GlobalVariable(
2189 CGM.getModule(), CGM.IntTy,
2190 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2191 /*Initializer=*/nullptr, VarName,
2192 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2193 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2197 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2198 llvm::FunctionType *FTy =
2199 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2200 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2201 return CGM.CreateRuntimeFunction(
2202 FTy, "_Init_thread_header",
2203 llvm::AttributeSet::get(CGM.getLLVMContext(),
2204 llvm::AttributeSet::FunctionIndex,
2205 llvm::Attribute::NoUnwind));
2208 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2209 llvm::FunctionType *FTy =
2210 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2211 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2212 return CGM.CreateRuntimeFunction(
2213 FTy, "_Init_thread_footer",
2214 llvm::AttributeSet::get(CGM.getLLVMContext(),
2215 llvm::AttributeSet::FunctionIndex,
2216 llvm::Attribute::NoUnwind));
2219 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2220 llvm::FunctionType *FTy =
2221 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2222 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2223 return CGM.CreateRuntimeFunction(
2224 FTy, "_Init_thread_abort",
2225 llvm::AttributeSet::get(CGM.getLLVMContext(),
2226 llvm::AttributeSet::FunctionIndex,
2227 llvm::Attribute::NoUnwind));
2231 struct ResetGuardBit : EHScopeStack::Cleanup {
2232 llvm::GlobalVariable *Guard;
2234 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2235 : Guard(Guard), GuardNum(GuardNum) {}
2237 void Emit(CodeGenFunction &CGF, Flags flags) override {
2238 // Reset the bit in the mask so that the static variable may be
2240 CGBuilderTy &Builder = CGF.Builder;
2241 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2242 llvm::ConstantInt *Mask =
2243 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2244 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2248 struct CallInitThreadAbort : EHScopeStack::Cleanup {
2249 llvm::GlobalVariable *Guard;
2250 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2252 void Emit(CodeGenFunction &CGF, Flags flags) override {
2253 // Calling _Init_thread_abort will reset the guard's state.
2254 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2259 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2260 llvm::GlobalVariable *GV,
2262 // MSVC only uses guards for static locals.
2263 if (!D.isStaticLocal()) {
2264 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2265 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2266 llvm::Function *F = CGF.CurFn;
2267 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2268 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2269 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2273 bool ThreadlocalStatic = D.getTLSKind();
2274 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2276 // Thread-safe static variables which aren't thread-specific have a
2277 // per-variable guard.
2278 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2280 CGBuilderTy &Builder = CGF.Builder;
2281 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2282 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2284 // Get the guard variable for this function if we have one already.
2285 GuardInfo *GI = nullptr;
2286 if (ThreadlocalStatic)
2287 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2288 else if (!ThreadsafeStatic)
2289 GI = &GuardVariableMap[D.getDeclContext()];
2291 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2293 if (D.isExternallyVisible()) {
2294 // Externally visible variables have to be numbered in Sema to properly
2295 // handle unreachable VarDecls.
2296 GuardNum = getContext().getStaticLocalNumber(&D);
2297 assert(GuardNum > 0);
2299 } else if (HasPerVariableGuard) {
2300 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2302 // Non-externally visible variables are numbered here in CodeGen.
2303 GuardNum = GI->BitIndex++;
2306 if (!HasPerVariableGuard && GuardNum >= 32) {
2307 if (D.isExternallyVisible())
2308 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2314 // Mangle the name for the guard.
2315 SmallString<256> GuardName;
2317 llvm::raw_svector_ostream Out(GuardName);
2318 if (HasPerVariableGuard)
2319 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2322 getMangleContext().mangleStaticGuardVariable(&D, Out);
2326 // Create the guard variable with a zero-initializer. Just absorb linkage,
2327 // visibility and dll storage class from the guarded variable.
2329 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2330 GV->getLinkage(), Zero, GuardName.str());
2331 GuardVar->setVisibility(GV->getVisibility());
2332 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2333 if (GuardVar->isWeakForLinker())
2334 GuardVar->setComdat(
2335 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2337 GuardVar->setThreadLocal(true);
2338 if (GI && !HasPerVariableGuard)
2339 GI->Guard = GuardVar;
2342 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2343 "static local from the same function had different linkage");
2345 if (!HasPerVariableGuard) {
2346 // Pseudo code for the test:
2347 // if (!(GuardVar & MyGuardBit)) {
2348 // GuardVar |= MyGuardBit;
2349 // ... initialize the object ...;
2352 // Test our bit from the guard variable.
2353 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2354 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2355 llvm::Value *IsInitialized =
2356 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2357 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2358 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2359 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2361 // Set our bit in the guard variable and emit the initializer and add a global
2362 // destructor if appropriate.
2363 CGF.EmitBlock(InitBlock);
2364 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2365 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2366 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2367 CGF.PopCleanupBlock();
2368 Builder.CreateBr(EndBlock);
2371 CGF.EmitBlock(EndBlock);
2373 // Pseudo code for the test:
2374 // if (TSS > _Init_thread_epoch) {
2375 // _Init_thread_header(&TSS);
2377 // ... initialize the object ...;
2378 // _Init_thread_footer(&TSS);
2382 // The algorithm is almost identical to what can be found in the appendix
2385 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2387 // This BasicBLock determines whether or not we have any work to do.
2388 llvm::LoadInst *FirstGuardLoad =
2389 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2390 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2391 llvm::LoadInst *InitThreadEpoch =
2392 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2393 llvm::Value *IsUninitialized =
2394 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2395 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2396 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2397 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2399 // This BasicBlock attempts to determine whether or not this thread is
2400 // responsible for doing the initialization.
2401 CGF.EmitBlock(AttemptInitBlock);
2402 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2403 llvm::LoadInst *SecondGuardLoad =
2404 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2405 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2406 llvm::Value *ShouldDoInit =
2407 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2408 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2409 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2411 // Ok, we ended up getting selected as the initializing thread.
2412 CGF.EmitBlock(InitBlock);
2413 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2414 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2415 CGF.PopCleanupBlock();
2416 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2417 Builder.CreateBr(EndBlock);
2419 CGF.EmitBlock(EndBlock);
2423 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2424 // Null-ness for function memptrs only depends on the first field, which is
2425 // the function pointer. The rest don't matter, so we can zero initialize.
2426 if (MPT->isMemberFunctionPointer())
2429 // The virtual base adjustment field is always -1 for null, so if we have one
2430 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2431 // valid field offset.
2432 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2433 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2434 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2435 RD->nullFieldOffsetIsZero());
2439 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2440 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2441 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2442 llvm::SmallVector<llvm::Type *, 4> fields;
2443 if (MPT->isMemberFunctionPointer())
2444 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2446 fields.push_back(CGM.IntTy); // FieldOffset
2448 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2450 fields.push_back(CGM.IntTy);
2451 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2452 fields.push_back(CGM.IntTy);
2453 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2454 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2456 if (fields.size() == 1)
2458 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2461 void MicrosoftCXXABI::
2462 GetNullMemberPointerFields(const MemberPointerType *MPT,
2463 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2464 assert(fields.empty());
2465 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2466 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2467 if (MPT->isMemberFunctionPointer()) {
2468 // FunctionPointerOrVirtualThunk
2469 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2471 if (RD->nullFieldOffsetIsZero())
2472 fields.push_back(getZeroInt()); // FieldOffset
2474 fields.push_back(getAllOnesInt()); // FieldOffset
2477 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2479 fields.push_back(getZeroInt());
2480 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2481 fields.push_back(getZeroInt());
2482 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2483 fields.push_back(getAllOnesInt());
2487 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2488 llvm::SmallVector<llvm::Constant *, 4> fields;
2489 GetNullMemberPointerFields(MPT, fields);
2490 if (fields.size() == 1)
2492 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2493 assert(Res->getType() == ConvertMemberPointerType(MPT));
2498 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2499 bool IsMemberFunction,
2500 const CXXRecordDecl *RD,
2501 CharUnits NonVirtualBaseAdjustment,
2502 unsigned VBTableIndex) {
2503 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2505 // Single inheritance class member pointer are represented as scalars instead
2507 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2510 llvm::SmallVector<llvm::Constant *, 4> fields;
2511 fields.push_back(FirstField);
2513 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2514 fields.push_back(llvm::ConstantInt::get(
2515 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2517 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2518 CharUnits Offs = CharUnits::Zero();
2520 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2521 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2524 // The rest of the fields are adjusted by conversions to a more derived class.
2525 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2526 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2528 return llvm::ConstantStruct::getAnon(fields);
2532 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2534 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2535 if (RD->getMSInheritanceModel() ==
2536 MSInheritanceAttr::Keyword_virtual_inheritance)
2537 offset -= getContext().getOffsetOfBaseWithVBPtr(RD);
2538 llvm::Constant *FirstField =
2539 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2540 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2541 CharUnits::Zero(), /*VBTableIndex=*/0);
2544 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2546 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2547 const ValueDecl *MPD = MP.getMemberPointerDecl();
2549 return EmitNullMemberPointer(DstTy);
2551 ASTContext &Ctx = getContext();
2552 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2555 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2556 C = EmitMemberFunctionPointer(MD);
2558 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2559 C = EmitMemberDataPointer(DstTy, FieldOffset);
2562 if (!MemberPointerPath.empty()) {
2563 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2564 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2565 const MemberPointerType *SrcTy =
2566 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2567 ->castAs<MemberPointerType>();
2569 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2570 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2571 const CXXRecordDecl *PrevRD = SrcRD;
2572 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2573 const CXXRecordDecl *Base = nullptr;
2574 const CXXRecordDecl *Derived = nullptr;
2575 if (DerivedMember) {
2582 for (const CXXBaseSpecifier &BS : Derived->bases())
2583 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2584 Base->getCanonicalDecl())
2585 DerivedToBasePath.push_back(&BS);
2588 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2590 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2591 : CK_BaseToDerivedMemberPointer;
2592 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2593 DerivedToBasePath.end(), C);
2599 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2600 assert(MD->isInstance() && "Member function must not be static!");
2602 MD = MD->getCanonicalDecl();
2603 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2604 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2605 CodeGenTypes &Types = CGM.getTypes();
2607 unsigned VBTableIndex = 0;
2608 llvm::Constant *FirstField;
2609 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2610 if (!MD->isVirtual()) {
2612 // Check whether the function has a computable LLVM signature.
2613 if (Types.isFuncTypeConvertible(FPT)) {
2614 // The function has a computable LLVM signature; use the correct type.
2615 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2617 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2618 // function type is incomplete.
2621 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2623 auto &VTableContext = CGM.getMicrosoftVTableContext();
2624 MicrosoftVTableContext::MethodVFTableLocation ML =
2625 VTableContext.getMethodVFTableLocation(MD);
2626 FirstField = EmitVirtualMemPtrThunk(MD, ML);
2627 // Include the vfptr adjustment if the method is in a non-primary vftable.
2628 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2630 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2633 if (VBTableIndex == 0 &&
2634 RD->getMSInheritanceModel() ==
2635 MSInheritanceAttr::Keyword_virtual_inheritance)
2636 NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD);
2638 // The rest of the fields are common with data member pointers.
2639 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2640 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2641 NonVirtualBaseAdjustment, VBTableIndex);
2644 /// Member pointers are the same if they're either bitwise identical *or* both
2645 /// null. Null-ness for function members is determined by the first field,
2646 /// while for data member pointers we must compare all fields.
2648 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2651 const MemberPointerType *MPT,
2653 CGBuilderTy &Builder = CGF.Builder;
2655 // Handle != comparisons by switching the sense of all boolean operations.
2656 llvm::ICmpInst::Predicate Eq;
2657 llvm::Instruction::BinaryOps And, Or;
2659 Eq = llvm::ICmpInst::ICMP_NE;
2660 And = llvm::Instruction::Or;
2661 Or = llvm::Instruction::And;
2663 Eq = llvm::ICmpInst::ICMP_EQ;
2664 And = llvm::Instruction::And;
2665 Or = llvm::Instruction::Or;
2668 // If this is a single field member pointer (single inheritance), this is a
2670 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2671 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2672 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2674 return Builder.CreateICmp(Eq, L, R);
2676 // Compare the first field.
2677 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2678 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2679 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2681 // Compare everything other than the first field.
2682 llvm::Value *Res = nullptr;
2683 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2684 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2685 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2686 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2687 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2689 Res = Builder.CreateBinOp(And, Res, Cmp);
2694 // Check if the first field is 0 if this is a function pointer.
2695 if (MPT->isMemberFunctionPointer()) {
2696 // (l1 == r1 && ...) || l0 == 0
2697 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2698 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2699 Res = Builder.CreateBinOp(Or, Res, IsZero);
2702 // Combine the comparison of the first field, which must always be true for
2703 // this comparison to succeeed.
2704 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2708 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2709 llvm::Value *MemPtr,
2710 const MemberPointerType *MPT) {
2711 CGBuilderTy &Builder = CGF.Builder;
2712 llvm::SmallVector<llvm::Constant *, 4> fields;
2713 // We only need one field for member functions.
2714 if (MPT->isMemberFunctionPointer())
2715 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2717 GetNullMemberPointerFields(MPT, fields);
2718 assert(!fields.empty());
2719 llvm::Value *FirstField = MemPtr;
2720 if (MemPtr->getType()->isStructTy())
2721 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2722 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2724 // For function member pointers, we only need to test the function pointer
2725 // field. The other fields if any can be garbage.
2726 if (MPT->isMemberFunctionPointer())
2729 // Otherwise, emit a series of compares and combine the results.
2730 for (int I = 1, E = fields.size(); I < E; ++I) {
2731 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2732 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2733 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2738 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2739 llvm::Constant *Val) {
2740 // Function pointers are null if the pointer in the first field is null.
2741 if (MPT->isMemberFunctionPointer()) {
2742 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2743 Val->getAggregateElement(0U) : Val;
2744 return FirstField->isNullValue();
2747 // If it's not a function pointer and it's zero initializable, we can easily
2749 if (isZeroInitializable(MPT) && Val->isNullValue())
2752 // Otherwise, break down all the fields for comparison. Hopefully these
2753 // little Constants are reused, while a big null struct might not be.
2754 llvm::SmallVector<llvm::Constant *, 4> Fields;
2755 GetNullMemberPointerFields(MPT, Fields);
2756 if (Fields.size() == 1) {
2757 assert(Val->getType()->isIntegerTy());
2758 return Val == Fields[0];
2762 for (I = 0, E = Fields.size(); I != E; ++I) {
2763 if (Val->getAggregateElement(I) != Fields[I])
2770 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2772 llvm::Value *VBPtrOffset,
2773 llvm::Value *VBTableOffset,
2774 llvm::Value **VBPtrOut) {
2775 CGBuilderTy &Builder = CGF.Builder;
2776 // Load the vbtable pointer from the vbptr in the instance.
2777 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2778 llvm::Value *VBPtr =
2779 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2780 if (VBPtrOut) *VBPtrOut = VBPtr;
2781 VBPtr = Builder.CreateBitCast(VBPtr,
2782 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2783 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2785 // Translate from byte offset to table index. It improves analyzability.
2786 llvm::Value *VBTableIndex = Builder.CreateAShr(
2787 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2788 "vbtindex", /*isExact=*/true);
2790 // Load an i32 offset from the vb-table.
2791 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2792 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2793 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2796 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2798 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2799 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2800 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2801 CGBuilderTy &Builder = CGF.Builder;
2802 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2803 llvm::BasicBlock *OriginalBB = nullptr;
2804 llvm::BasicBlock *SkipAdjustBB = nullptr;
2805 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2807 // In the unspecified inheritance model, there might not be a vbtable at all,
2808 // in which case we need to skip the virtual base lookup. If there is a
2809 // vbtable, the first entry is a no-op entry that gives back the original
2810 // base, so look for a virtual base adjustment offset of zero.
2812 OriginalBB = Builder.GetInsertBlock();
2813 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2814 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2815 llvm::Value *IsVirtual =
2816 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2818 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2819 CGF.EmitBlock(VBaseAdjustBB);
2822 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2823 // know the vbptr offset.
2825 CharUnits offs = CharUnits::Zero();
2826 if (!RD->hasDefinition()) {
2827 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2828 unsigned DiagID = Diags.getCustomDiagID(
2829 DiagnosticsEngine::Error,
2830 "member pointer representation requires a "
2831 "complete class type for %0 to perform this expression");
2832 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2833 } else if (RD->getNumVBases())
2834 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2835 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2837 llvm::Value *VBPtr = nullptr;
2838 llvm::Value *VBaseOffs =
2839 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2840 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2842 // Merge control flow with the case where we didn't have to adjust.
2843 if (VBaseAdjustBB) {
2844 Builder.CreateBr(SkipAdjustBB);
2845 CGF.EmitBlock(SkipAdjustBB);
2846 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2847 Phi->addIncoming(Base, OriginalBB);
2848 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2851 return AdjustedBase;
2854 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2855 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2856 const MemberPointerType *MPT) {
2857 assert(MPT->isMemberDataPointer());
2858 unsigned AS = Base->getType()->getPointerAddressSpace();
2860 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2861 CGBuilderTy &Builder = CGF.Builder;
2862 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2863 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2865 // Extract the fields we need, regardless of model. We'll apply them if we
2867 llvm::Value *FieldOffset = MemPtr;
2868 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2869 llvm::Value *VBPtrOffset = nullptr;
2870 if (MemPtr->getType()->isStructTy()) {
2871 // We need to extract values.
2873 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2874 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2875 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2876 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2877 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2880 if (VirtualBaseAdjustmentOffset) {
2881 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2886 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2888 // Apply the offset, which we assume is non-null.
2890 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2892 // Cast the address to the appropriate pointer type, adopting the address
2893 // space of the base pointer.
2894 return Builder.CreateBitCast(Addr, PType);
2898 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2901 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2902 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2903 E->getCastKind() == CK_ReinterpretMemberPointer);
2905 // Use constant emission if we can.
2906 if (isa<llvm::Constant>(Src))
2907 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2909 // We may be adding or dropping fields from the member pointer, so we need
2910 // both types and the inheritance models of both records.
2911 const MemberPointerType *SrcTy =
2912 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2913 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2914 bool IsFunc = SrcTy->isMemberFunctionPointer();
2916 // If the classes use the same null representation, reinterpret_cast is a nop.
2917 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2918 if (IsReinterpret && IsFunc)
2921 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2922 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2923 if (IsReinterpret &&
2924 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2927 CGBuilderTy &Builder = CGF.Builder;
2929 // Branch past the conversion if Src is null.
2930 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2931 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2933 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2934 // pointer value of the destination type.
2935 if (IsReinterpret) {
2936 // For reinterpret casts, sema ensures that src and dst are both functions
2937 // or data and have the same size, which means the LLVM types should match.
2938 assert(Src->getType() == DstNull->getType());
2939 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2942 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2943 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2944 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2945 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2946 CGF.EmitBlock(ConvertBB);
2948 llvm::Value *Dst = EmitNonNullMemberPointerConversion(
2949 SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src,
2952 Builder.CreateBr(ContinueBB);
2954 // In the continuation, choose between DstNull and Dst.
2955 CGF.EmitBlock(ContinueBB);
2956 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2957 Phi->addIncoming(DstNull, OriginalBB);
2958 Phi->addIncoming(Dst, ConvertBB);
2962 llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion(
2963 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
2964 CastExpr::path_const_iterator PathBegin,
2965 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
2966 CGBuilderTy &Builder) {
2967 const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2968 const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2969 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2970 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2971 bool IsFunc = SrcTy->isMemberFunctionPointer();
2972 bool IsConstant = isa<llvm::Constant>(Src);
2975 llvm::Value *FirstField = Src;
2976 llvm::Value *NonVirtualBaseAdjustment = getZeroInt();
2977 llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt();
2978 llvm::Value *VBPtrOffset = getZeroInt();
2979 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2980 // We need to extract values.
2982 FirstField = Builder.CreateExtractValue(Src, I++);
2983 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2984 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2985 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2986 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2987 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2988 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2991 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
2992 const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy;
2993 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
2995 // For data pointers, we adjust the field offset directly. For functions, we
2996 // have a separate field.
2997 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2999 // The virtual inheritance model has a quirk: the virtual base table is always
3000 // referenced when dereferencing a member pointer even if the member pointer
3001 // is non-virtual. This is accounted for by adjusting the non-virtual offset
3002 // to point backwards to the top of the MDC from the first VBase. Undo this
3003 // adjustment to normalize the member pointer.
3004 llvm::Value *SrcVBIndexEqZero =
3005 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3006 if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3007 if (int64_t SrcOffsetToFirstVBase =
3008 getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) {
3009 llvm::Value *UndoSrcAdjustment = Builder.CreateSelect(
3011 llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase),
3013 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment);
3017 // A non-zero vbindex implies that we are dealing with a source member in a
3018 // floating virtual base in addition to some non-virtual offset. If the
3019 // vbindex is zero, we are dealing with a source that exists in a non-virtual,
3020 // fixed, base. The difference between these two cases is that the vbindex +
3021 // nvoffset *always* point to the member regardless of what context they are
3022 // evaluated in so long as the vbindex is adjusted. A member inside a fixed
3023 // base requires explicit nv adjustment.
3024 llvm::Constant *BaseClassOffset = llvm::ConstantInt::get(
3026 CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd)
3029 llvm::Value *NVDisp;
3030 if (IsDerivedToBase)
3031 NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj");
3033 NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj");
3035 NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt());
3037 // Update the vbindex to an appropriate value in the destination because
3038 // SrcRD's vbtable might not be a strict prefix of the one in DstRD.
3039 llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero;
3040 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) &&
3041 MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) {
3042 if (llvm::GlobalVariable *VDispMap =
3043 getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) {
3044 llvm::Value *VBIndex = Builder.CreateExactUDiv(
3045 VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4));
3047 llvm::Constant *Mapping = VDispMap->getInitializer();
3048 VirtualBaseAdjustmentOffset =
3049 Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex));
3051 llvm::Value *Idxs[] = {getZeroInt(), VBIndex};
3052 VirtualBaseAdjustmentOffset =
3053 Builder.CreateLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs));
3057 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3061 // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize
3062 // it to the offset of the vbptr.
3063 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) {
3064 llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get(
3066 getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity());
3068 Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset);
3071 // Likewise, apply a similar adjustment so that dereferencing the member
3072 // pointer correctly accounts for the distance between the start of the first
3073 // virtual base and the top of the MDC.
3074 if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3075 if (int64_t DstOffsetToFirstVBase =
3076 getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) {
3077 llvm::Value *DoDstAdjustment = Builder.CreateSelect(
3079 llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase),
3081 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment);
3085 // Recompose dst from the null struct and the adjusted fields from src.
3087 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
3090 Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy));
3092 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
3093 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3094 Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++);
3095 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3096 Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++);
3097 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3098 Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++);
3104 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
3105 llvm::Constant *Src) {
3106 const MemberPointerType *SrcTy =
3107 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3108 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3110 CastKind CK = E->getCastKind();
3112 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
3113 E->path_end(), Src);
3116 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
3117 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3118 CastExpr::path_const_iterator PathBegin,
3119 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
3120 assert(CK == CK_DerivedToBaseMemberPointer ||
3121 CK == CK_BaseToDerivedMemberPointer ||
3122 CK == CK_ReinterpretMemberPointer);
3123 // If src is null, emit a new null for dst. We can't return src because dst
3124 // might have a new representation.
3125 if (MemberPointerConstantIsNull(SrcTy, Src))
3126 return EmitNullMemberPointer(DstTy);
3128 // We don't need to do anything for reinterpret_casts of non-null member
3129 // pointers. We should only get here when the two type representations have
3131 if (CK == CK_ReinterpretMemberPointer)
3134 CGBuilderTy Builder(CGM.getLLVMContext());
3135 auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion(
3136 SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder));
3141 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3142 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
3143 llvm::Value *MemPtr, const MemberPointerType *MPT) {
3144 assert(MPT->isMemberFunctionPointer());
3145 const FunctionProtoType *FPT =
3146 MPT->getPointeeType()->castAs<FunctionProtoType>();
3147 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3148 llvm::FunctionType *FTy =
3149 CGM.getTypes().GetFunctionType(
3150 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
3151 CGBuilderTy &Builder = CGF.Builder;
3153 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3155 // Extract the fields we need, regardless of model. We'll apply them if we
3157 llvm::Value *FunctionPointer = MemPtr;
3158 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3159 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3160 llvm::Value *VBPtrOffset = nullptr;
3161 if (MemPtr->getType()->isStructTy()) {
3162 // We need to extract values.
3164 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3165 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3166 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3167 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3168 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3169 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3170 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3173 if (VirtualBaseAdjustmentOffset) {
3174 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
3178 if (NonVirtualBaseAdjustment) {
3179 // Apply the adjustment and cast back to the original struct type.
3180 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
3181 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3182 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
3185 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3188 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3189 return new MicrosoftCXXABI(CGM);
3192 // MS RTTI Overview:
3193 // The run time type information emitted by cl.exe contains 5 distinct types of
3194 // structures. Many of them reference each other.
3196 // TypeInfo: Static classes that are returned by typeid.
3198 // CompleteObjectLocator: Referenced by vftables. They contain information
3199 // required for dynamic casting, including OffsetFromTop. They also contain
3200 // a reference to the TypeInfo for the type and a reference to the
3201 // CompleteHierarchyDescriptor for the type.
3203 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3204 // Used during dynamic_cast to walk a class hierarchy. References a base
3205 // class array and the size of said array.
3207 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3208 // somewhat of a misnomer because the most derived class is also in the list
3209 // as well as multiple copies of virtual bases (if they occur multiple times
3210 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3211 // every path in the hierarchy, in pre-order depth first order. Note, we do
3212 // not declare a specific llvm type for BaseClassArray, it's merely an array
3213 // of BaseClassDescriptor pointers.
3215 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3216 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3217 // BaseClassArray is. It contains information about a class within a
3218 // hierarchy such as: is this base is ambiguous and what is its offset in the
3219 // vbtable. The names of the BaseClassDescriptors have all of their fields
3220 // mangled into them so they can be aggressively deduplicated by the linker.
3222 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3223 StringRef MangledName("\01??_7type_info@@6B@");
3224 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3226 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3228 llvm::GlobalVariable::ExternalLinkage,
3229 /*Initializer=*/nullptr, MangledName);
3234 /// \brief A Helper struct that stores information about a class in a class
3235 /// hierarchy. The information stored in these structs struct is used during
3236 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3237 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3238 // implicit depth first pre-order tree connectivity. getFirstChild and
3239 // getNextSibling allow us to walk the tree efficiently.
3240 struct MSRTTIClass {
3242 IsPrivateOnPath = 1 | 8,
3246 HasHierarchyDescriptor = 64
3248 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3249 uint32_t initialize(const MSRTTIClass *Parent,
3250 const CXXBaseSpecifier *Specifier);
3252 MSRTTIClass *getFirstChild() { return this + 1; }
3253 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3254 return Child + 1 + Child->NumBases;
3257 const CXXRecordDecl *RD, *VirtualRoot;
3258 uint32_t Flags, NumBases, OffsetInVBase;
3261 /// \brief Recursively initialize the base class array.
3262 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3263 const CXXBaseSpecifier *Specifier) {
3264 Flags = HasHierarchyDescriptor;
3266 VirtualRoot = nullptr;
3269 if (Specifier->getAccessSpecifier() != AS_public)
3270 Flags |= IsPrivate | IsPrivateOnPath;
3271 if (Specifier->isVirtual()) {
3276 if (Parent->Flags & IsPrivateOnPath)
3277 Flags |= IsPrivateOnPath;
3278 VirtualRoot = Parent->VirtualRoot;
3279 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3280 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3284 MSRTTIClass *Child = getFirstChild();
3285 for (const CXXBaseSpecifier &Base : RD->bases()) {
3286 NumBases += Child->initialize(this, &Base) + 1;
3287 Child = getNextChild(Child);
3292 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3293 switch (Ty->getLinkage()) {
3295 case InternalLinkage:
3296 case UniqueExternalLinkage:
3297 return llvm::GlobalValue::InternalLinkage;
3299 case VisibleNoLinkage:
3300 case ExternalLinkage:
3301 return llvm::GlobalValue::LinkOnceODRLinkage;
3303 llvm_unreachable("Invalid linkage!");
3306 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3307 /// calls to the module and information about the most derived class in a
3309 struct MSRTTIBuilder {
3311 HasBranchingHierarchy = 1,
3312 HasVirtualBranchingHierarchy = 2,
3313 HasAmbiguousBases = 4
3316 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3317 : CGM(ABI.CGM), Context(CGM.getContext()),
3318 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3319 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3322 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3323 llvm::GlobalVariable *
3324 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3325 llvm::GlobalVariable *getClassHierarchyDescriptor();
3326 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3329 ASTContext &Context;
3330 llvm::LLVMContext &VMContext;
3331 llvm::Module &Module;
3332 const CXXRecordDecl *RD;
3333 llvm::GlobalVariable::LinkageTypes Linkage;
3334 MicrosoftCXXABI &ABI;
3339 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3341 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3342 const CXXRecordDecl *RD) {
3343 Classes.push_back(MSRTTIClass(RD));
3344 for (const CXXBaseSpecifier &Base : RD->bases())
3345 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3348 /// \brief Find ambiguity among base classes.
3350 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3351 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3352 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3353 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3354 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3355 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3356 !VirtualBases.insert(Class->RD).second) {
3357 Class = MSRTTIClass::getNextChild(Class);
3360 if (!UniqueBases.insert(Class->RD).second)
3361 AmbiguousBases.insert(Class->RD);
3364 if (AmbiguousBases.empty())
3366 for (MSRTTIClass &Class : Classes)
3367 if (AmbiguousBases.count(Class.RD))
3368 Class.Flags |= MSRTTIClass::IsAmbiguous;
3371 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3372 SmallString<256> MangledName;
3374 llvm::raw_svector_ostream Out(MangledName);
3375 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3378 // Check to see if we've already declared this ClassHierarchyDescriptor.
3379 if (auto CHD = Module.getNamedGlobal(MangledName))
3382 // Serialize the class hierarchy and initialize the CHD Fields.
3383 SmallVector<MSRTTIClass, 8> Classes;
3384 serializeClassHierarchy(Classes, RD);
3385 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3386 detectAmbiguousBases(Classes);
3388 for (auto Class : Classes) {
3389 if (Class.RD->getNumBases() > 1)
3390 Flags |= HasBranchingHierarchy;
3391 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3392 // believe the field isn't actually used.
3393 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3394 Flags |= HasAmbiguousBases;
3396 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3397 Flags |= HasVirtualBranchingHierarchy;
3398 // These gep indices are used to get the address of the first element of the
3399 // base class array.
3400 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3401 llvm::ConstantInt::get(CGM.IntTy, 0)};
3403 // Forward-declare the class hierarchy descriptor
3404 auto Type = ABI.getClassHierarchyDescriptorType();
3405 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3406 /*Initializer=*/nullptr,
3407 StringRef(MangledName));
3408 if (CHD->isWeakForLinker())
3409 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3411 auto *Bases = getBaseClassArray(Classes);
3413 // Initialize the base class ClassHierarchyDescriptor.
3414 llvm::Constant *Fields[] = {
3415 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3416 llvm::ConstantInt::get(CGM.IntTy, Flags),
3417 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3418 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3419 Bases->getValueType(), Bases,
3420 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3422 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3426 llvm::GlobalVariable *
3427 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3428 SmallString<256> MangledName;
3430 llvm::raw_svector_ostream Out(MangledName);
3431 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3434 // Forward-declare the base class array.
3435 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3436 // mode) bytes of padding. We provide a pointer sized amount of padding by
3437 // adding +1 to Classes.size(). The sections have pointer alignment and are
3438 // marked pick-any so it shouldn't matter.
3439 llvm::Type *PtrType = ABI.getImageRelativeType(
3440 ABI.getBaseClassDescriptorType()->getPointerTo());
3441 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3443 new llvm::GlobalVariable(Module, ArrType,
3444 /*Constant=*/true, Linkage,
3445 /*Initializer=*/nullptr, StringRef(MangledName));
3446 if (BCA->isWeakForLinker())
3447 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3449 // Initialize the BaseClassArray.
3450 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3451 for (MSRTTIClass &Class : Classes)
3452 BaseClassArrayData.push_back(
3453 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3454 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3455 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3459 llvm::GlobalVariable *
3460 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3461 // Compute the fields for the BaseClassDescriptor. They are computed up front
3462 // because they are mangled into the name of the object.
3463 uint32_t OffsetInVBTable = 0;
3464 int32_t VBPtrOffset = -1;
3465 if (Class.VirtualRoot) {
3466 auto &VTableContext = CGM.getMicrosoftVTableContext();
3467 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3468 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3471 SmallString<256> MangledName;
3473 llvm::raw_svector_ostream Out(MangledName);
3474 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3475 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3479 // Check to see if we've already declared this object.
3480 if (auto BCD = Module.getNamedGlobal(MangledName))
3483 // Forward-declare the base class descriptor.
3484 auto Type = ABI.getBaseClassDescriptorType();
3486 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3487 /*Initializer=*/nullptr, StringRef(MangledName));
3488 if (BCD->isWeakForLinker())
3489 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3491 // Initialize the BaseClassDescriptor.
3492 llvm::Constant *Fields[] = {
3493 ABI.getImageRelativeConstant(
3494 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3495 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3496 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3497 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3498 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3499 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3500 ABI.getImageRelativeConstant(
3501 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3503 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3507 llvm::GlobalVariable *
3508 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3509 SmallString<256> MangledName;
3511 llvm::raw_svector_ostream Out(MangledName);
3512 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3515 // Check to see if we've already computed this complete object locator.
3516 if (auto COL = Module.getNamedGlobal(MangledName))
3519 // Compute the fields of the complete object locator.
3520 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3521 int VFPtrOffset = 0;
3522 // The offset includes the vtordisp if one exists.
3523 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3524 if (Context.getASTRecordLayout(RD)
3525 .getVBaseOffsetsMap()
3527 ->second.hasVtorDisp())
3528 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3530 // Forward-declare the complete object locator.
3531 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3532 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3533 /*Initializer=*/nullptr, StringRef(MangledName));
3535 // Initialize the CompleteObjectLocator.
3536 llvm::Constant *Fields[] = {
3537 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3538 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3539 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3540 ABI.getImageRelativeConstant(
3541 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3542 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3543 ABI.getImageRelativeConstant(COL),
3545 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3546 if (!ABI.isImageRelative())
3547 FieldsRef = FieldsRef.drop_back();
3548 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3549 if (COL->isWeakForLinker())
3550 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3554 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3555 bool &IsConst, bool &IsVolatile) {
3556 T = Context.getExceptionObjectType(T);
3558 // C++14 [except.handle]p3:
3559 // A handler is a match for an exception object of type E if [...]
3560 // - the handler is of type cv T or const T& where T is a pointer type and
3561 // E is a pointer type that can be converted to T by [...]
3562 // - a qualification conversion
3565 QualType PointeeType = T->getPointeeType();
3566 if (!PointeeType.isNull()) {
3567 IsConst = PointeeType.isConstQualified();
3568 IsVolatile = PointeeType.isVolatileQualified();
3571 // Member pointer types like "const int A::*" are represented by having RTTI
3572 // for "int A::*" and separately storing the const qualifier.
3573 if (const auto *MPTy = T->getAs<MemberPointerType>())
3574 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3577 // Pointer types like "const int * const *" are represented by having RTTI
3578 // for "const int **" and separately storing the const qualifier.
3579 if (T->isPointerType())
3580 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3586 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3587 QualType CatchHandlerType) {
3588 // TypeDescriptors for exceptions never have qualified pointer types,
3589 // qualifiers are stored seperately in order to support qualification
3591 bool IsConst, IsVolatile;
3592 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3594 bool IsReference = CatchHandlerType->isReferenceType();
3604 SmallString<256> MangledName;
3606 llvm::raw_svector_ostream Out(MangledName);
3607 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3610 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3611 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3613 llvm::Constant *Fields[] = {
3614 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3615 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3617 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3618 auto *Var = new llvm::GlobalVariable(
3619 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3620 llvm::GlobalValue::PrivateLinkage,
3621 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3622 StringRef(MangledName));
3623 Var->setUnnamedAddr(true);
3624 Var->setSection("llvm.metadata");
3628 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3629 /// llvm::GlobalVariable * because different type descriptors have different
3630 /// types, and need to be abstracted. They are abstracting by casting the
3631 /// address to an Int8PtrTy.
3632 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3633 SmallString<256> MangledName;
3635 llvm::raw_svector_ostream Out(MangledName);
3636 getMangleContext().mangleCXXRTTI(Type, Out);
3639 // Check to see if we've already declared this TypeDescriptor.
3640 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3641 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3643 // Compute the fields for the TypeDescriptor.
3644 SmallString<256> TypeInfoString;
3646 llvm::raw_svector_ostream Out(TypeInfoString);
3647 getMangleContext().mangleCXXRTTIName(Type, Out);
3650 // Declare and initialize the TypeDescriptor.
3651 llvm::Constant *Fields[] = {
3652 getTypeInfoVTable(CGM), // VFPtr
3653 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3654 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3655 llvm::StructType *TypeDescriptorType =
3656 getTypeDescriptorType(TypeInfoString);
3657 auto *Var = new llvm::GlobalVariable(
3658 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3659 getLinkageForRTTI(Type),
3660 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3661 StringRef(MangledName));
3662 if (Var->isWeakForLinker())
3663 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3664 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3667 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3668 llvm::GlobalVariable *
3669 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3670 const VPtrInfo *Info) {
3671 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3674 static void emitCXXConstructor(CodeGenModule &CGM,
3675 const CXXConstructorDecl *ctor,
3676 StructorType ctorType) {
3677 // There are no constructor variants, always emit the complete destructor.
3678 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3679 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3682 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3683 StructorType dtorType) {
3684 // The complete destructor is equivalent to the base destructor for
3685 // classes with no virtual bases, so try to emit it as an alias.
3686 if (!dtor->getParent()->getNumVBases() &&
3687 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3688 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3689 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3690 if (ProducedAlias) {
3691 if (dtorType == StructorType::Complete)
3693 if (dtor->isVirtual())
3694 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3698 // The base destructor is equivalent to the base destructor of its
3699 // base class if there is exactly one non-virtual base class with a
3700 // non-trivial destructor, there are no fields with a non-trivial
3701 // destructor, and the body of the destructor is trivial.
3702 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3705 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3706 if (Fn->isWeakForLinker())
3707 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3710 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3711 StructorType Type) {
3712 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3713 emitCXXConstructor(CGM, CD, Type);
3716 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3720 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3722 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3724 // Calculate the mangled name.
3725 SmallString<256> ThunkName;
3726 llvm::raw_svector_ostream Out(ThunkName);
3727 getMangleContext().mangleCXXCtor(CD, CT, Out);
3730 // If the thunk has been generated previously, just return it.
3731 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3732 return cast<llvm::Function>(GV);
3734 // Create the llvm::Function.
3735 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3736 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3737 const CXXRecordDecl *RD = CD->getParent();
3738 QualType RecordTy = getContext().getRecordType(RD);
3739 llvm::Function *ThunkFn = llvm::Function::Create(
3740 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3741 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3742 FnInfo.getEffectiveCallingConvention()));
3743 if (ThunkFn->isWeakForLinker())
3744 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
3745 bool IsCopy = CT == Ctor_CopyingClosure;
3748 CodeGenFunction CGF(CGM);
3749 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3751 // Build FunctionArgs.
3752 FunctionArgList FunctionArgs;
3754 // A constructor always starts with a 'this' pointer as its first argument.
3755 buildThisParam(CGF, FunctionArgs);
3757 // Following the 'this' pointer is a reference to the source object that we
3758 // are copying from.
3759 ImplicitParamDecl SrcParam(
3760 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3761 getContext().getLValueReferenceType(RecordTy,
3762 /*SpelledAsLValue=*/true));
3764 FunctionArgs.push_back(&SrcParam);
3766 // Constructors for classes which utilize virtual bases have an additional
3767 // parameter which indicates whether or not it is being delegated to by a more
3768 // derived constructor.
3769 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3770 &getContext().Idents.get("is_most_derived"),
3771 getContext().IntTy);
3772 // Only add the parameter to the list if thie class has virtual bases.
3773 if (RD->getNumVBases() > 0)
3774 FunctionArgs.push_back(&IsMostDerived);
3776 // Start defining the function.
3777 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3778 FunctionArgs, CD->getLocation(), SourceLocation());
3780 llvm::Value *This = getThisValue(CGF);
3782 llvm::Value *SrcVal =
3783 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3788 // Push the this ptr.
3789 Args.add(RValue::get(This), CD->getThisType(getContext()));
3791 // Push the src ptr.
3793 Args.add(RValue::get(SrcVal), SrcParam.getType());
3795 // Add the rest of the default arguments.
3796 std::vector<Stmt *> ArgVec;
3797 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3798 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3799 assert(DefaultArg && "sema forgot to instantiate default args");
3800 ArgVec.push_back(DefaultArg);
3803 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3805 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3806 ConstExprIterator ArgBegin(ArgVec.data()),
3807 ArgEnd(ArgVec.data() + ArgVec.size());
3808 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3810 // Insert any ABI-specific implicit constructor arguments.
3811 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3812 /*ForVirtualBase=*/false,
3813 /*Delegating=*/false, Args);
3815 // Call the destructor with our arguments.
3816 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3817 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3818 Args, CD, Ctor_Complete, ExtraArgs);
3819 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3821 Cleanups.ForceCleanup();
3823 // Emit the ret instruction, remove any temporary instructions created for the
3825 CGF.FinishFunction(SourceLocation());
3830 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3832 int32_t VBPtrOffset,
3834 assert(!T->isReferenceType());
3836 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3837 const CXXConstructorDecl *CD =
3838 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3839 CXXCtorType CT = Ctor_Complete;
3841 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3842 CT = Ctor_CopyingClosure;
3844 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3845 SmallString<256> MangledName;
3847 llvm::raw_svector_ostream Out(MangledName);
3848 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3849 VBPtrOffset, VBIndex, Out);
3851 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3852 return getImageRelativeConstant(GV);
3854 // The TypeDescriptor is used by the runtime to determine if a catch handler
3855 // is appropriate for the exception object.
3856 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3858 // The runtime is responsible for calling the copy constructor if the
3859 // exception is caught by value.
3860 llvm::Constant *CopyCtor;
3862 if (CT == Ctor_CopyingClosure)
3863 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3865 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3867 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3869 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3871 CopyCtor = getImageRelativeConstant(CopyCtor);
3873 bool IsScalar = !RD;
3874 bool HasVirtualBases = false;
3875 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3876 QualType PointeeType = T;
3877 if (T->isPointerType())
3878 PointeeType = T->getPointeeType();
3879 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3880 HasVirtualBases = RD->getNumVBases() > 0;
3881 if (IdentifierInfo *II = RD->getIdentifier())
3882 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3885 // Encode the relevant CatchableType properties into the Flags bitfield.
3886 // FIXME: Figure out how bits 2 or 8 can get set.
3890 if (HasVirtualBases)
3895 llvm::Constant *Fields[] = {
3896 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3897 TD, // TypeDescriptor
3898 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3899 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3900 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3901 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3902 CopyCtor // CopyCtor
3904 llvm::StructType *CTType = getCatchableTypeType();
3905 auto *GV = new llvm::GlobalVariable(
3906 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3907 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3908 GV->setUnnamedAddr(true);
3909 GV->setSection(".xdata");
3910 if (GV->isWeakForLinker())
3911 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3912 return getImageRelativeConstant(GV);
3915 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3916 assert(!T->isReferenceType());
3918 // See if we've already generated a CatchableTypeArray for this type before.
3919 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3923 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3924 // using a SmallSetVector. Duplicates may arise due to virtual bases
3925 // occurring more than once in the hierarchy.
3926 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3928 // C++14 [except.handle]p3:
3929 // A handler is a match for an exception object of type E if [...]
3930 // - the handler is of type cv T or cv T& and T is an unambiguous public
3931 // base class of E, or
3932 // - the handler is of type cv T or const T& where T is a pointer type and
3933 // E is a pointer type that can be converted to T by [...]
3934 // - a standard pointer conversion (4.10) not involving conversions to
3935 // pointers to private or protected or ambiguous classes
3936 const CXXRecordDecl *MostDerivedClass = nullptr;
3937 bool IsPointer = T->isPointerType();
3939 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3941 MostDerivedClass = T->getAsCXXRecordDecl();
3943 // Collect all the unambiguous public bases of the MostDerivedClass.
3944 if (MostDerivedClass) {
3945 const ASTContext &Context = getContext();
3946 const ASTRecordLayout &MostDerivedLayout =
3947 Context.getASTRecordLayout(MostDerivedClass);
3948 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3949 SmallVector<MSRTTIClass, 8> Classes;
3950 serializeClassHierarchy(Classes, MostDerivedClass);
3951 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3952 detectAmbiguousBases(Classes);
3953 for (const MSRTTIClass &Class : Classes) {
3954 // Skip any ambiguous or private bases.
3956 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3958 // Write down how to convert from a derived pointer to a base pointer.
3959 uint32_t OffsetInVBTable = 0;
3960 int32_t VBPtrOffset = -1;
3961 if (Class.VirtualRoot) {
3963 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3964 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3967 // Turn our record back into a pointer if the exception object is a
3969 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3971 RTTITy = Context.getPointerType(RTTITy);
3972 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3973 VBPtrOffset, OffsetInVBTable));
3977 // C++14 [except.handle]p3:
3978 // A handler is a match for an exception object of type E if
3979 // - The handler is of type cv T or cv T& and E and T are the same type
3980 // (ignoring the top-level cv-qualifiers)
3981 CatchableTypes.insert(getCatchableType(T));
3983 // C++14 [except.handle]p3:
3984 // A handler is a match for an exception object of type E if
3985 // - the handler is of type cv T or const T& where T is a pointer type and
3986 // E is a pointer type that can be converted to T by [...]
3987 // - a standard pointer conversion (4.10) not involving conversions to
3988 // pointers to private or protected or ambiguous classes
3990 // C++14 [conv.ptr]p2:
3991 // A prvalue of type "pointer to cv T," where T is an object type, can be
3992 // converted to a prvalue of type "pointer to cv void".
3993 if (IsPointer && T->getPointeeType()->isObjectType())
3994 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3996 // C++14 [except.handle]p3:
3997 // A handler is a match for an exception object of type E if [...]
3998 // - the handler is of type cv T or const T& where T is a pointer or
3999 // pointer to member type and E is std::nullptr_t.
4001 // We cannot possibly list all possible pointer types here, making this
4002 // implementation incompatible with the standard. However, MSVC includes an
4003 // entry for pointer-to-void in this case. Let's do the same.
4004 if (T->isNullPtrType())
4005 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4007 uint32_t NumEntries = CatchableTypes.size();
4008 llvm::Type *CTType =
4009 getImageRelativeType(getCatchableTypeType()->getPointerTo());
4010 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
4011 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
4012 llvm::Constant *Fields[] = {
4013 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
4014 llvm::ConstantArray::get(
4015 AT, llvm::makeArrayRef(CatchableTypes.begin(),
4016 CatchableTypes.end())) // CatchableTypes
4018 SmallString<256> MangledName;
4020 llvm::raw_svector_ostream Out(MangledName);
4021 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
4023 CTA = new llvm::GlobalVariable(
4024 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
4025 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
4026 CTA->setUnnamedAddr(true);
4027 CTA->setSection(".xdata");
4028 if (CTA->isWeakForLinker())
4029 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
4033 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
4034 bool IsConst, IsVolatile;
4035 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
4037 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
4038 // the exception object may be caught as.
4039 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
4040 // The first field in a CatchableTypeArray is the number of CatchableTypes.
4041 // This is used as a component of the mangled name which means that we need to
4042 // know what it is in order to see if we have previously generated the
4044 uint32_t NumEntries =
4045 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
4046 ->getLimitedValue();
4048 SmallString<256> MangledName;
4050 llvm::raw_svector_ostream Out(MangledName);
4051 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
4055 // Reuse a previously generated ThrowInfo if we have generated an appropriate
4057 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
4060 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
4061 // be at least as CV qualified. Encode this requirement into the Flags
4069 // The cleanup-function (a destructor) must be called when the exception
4070 // object's lifetime ends.
4071 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
4072 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4073 if (CXXDestructorDecl *DtorD = RD->getDestructor())
4074 if (!DtorD->isTrivial())
4075 CleanupFn = llvm::ConstantExpr::getBitCast(
4076 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
4078 // This is unused as far as we can tell, initialize it to null.
4079 llvm::Constant *ForwardCompat =
4080 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
4081 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
4082 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
4083 llvm::StructType *TIType = getThrowInfoType();
4084 llvm::Constant *Fields[] = {
4085 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4086 getImageRelativeConstant(CleanupFn), // CleanupFn
4087 ForwardCompat, // ForwardCompat
4088 PointerToCatchableTypes // CatchableTypeArray
4090 auto *GV = new llvm::GlobalVariable(
4091 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
4092 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
4093 GV->setUnnamedAddr(true);
4094 GV->setSection(".xdata");
4095 if (GV->isWeakForLinker())
4096 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4100 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
4101 const Expr *SubExpr = E->getSubExpr();
4102 QualType ThrowType = SubExpr->getType();
4103 // The exception object lives on the stack and it's address is passed to the
4104 // runtime function.
4105 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
4106 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4109 // The so-called ThrowInfo is used to describe how the exception object may be
4111 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4113 // Call into the runtime to throw the exception.
4114 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
4115 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);