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");
1469 CharUnits PointerWidth = getContext().toCharUnitsFromBits(
1470 getContext().getTargetInfo().getPointerWidth(0));
1472 // FIXME: Add blacklisting scheme.
1474 if (Info->PathToBaseWithVPtr.empty()) {
1475 BitsetsMD->addOperand(
1476 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, RD));
1480 // Add a bitset entry for the least derived base belonging to this vftable.
1481 BitsetsMD->addOperand(CGM.CreateVTableBitSetEntry(
1482 VTable, PointerWidth, Info->PathToBaseWithVPtr.back()));
1484 // Add a bitset entry for each derived class that is laid out at the same
1485 // offset as the least derived base.
1486 for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) {
1487 const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1];
1488 const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I];
1490 const ASTRecordLayout &Layout =
1491 getContext().getASTRecordLayout(DerivedRD);
1493 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1494 if (VBI == Layout.getVBaseOffsetsMap().end())
1495 Offset = Layout.getBaseClassOffset(BaseRD);
1497 Offset = VBI->second.VBaseOffset;
1498 if (!Offset.isZero())
1500 BitsetsMD->addOperand(
1501 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, DerivedRD));
1504 // Finally do the same for the most derived class.
1505 if (Info->FullOffsetInMDC.isZero())
1506 BitsetsMD->addOperand(
1507 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, RD));
1510 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1511 const CXXRecordDecl *RD) {
1512 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1513 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1515 for (VPtrInfo *Info : VFPtrs) {
1516 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1517 if (VTable->hasInitializer())
1520 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1521 ? getMSCompleteObjectLocator(RD, Info)
1524 const VTableLayout &VTLayout =
1525 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1526 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1527 RD, VTLayout.vtable_component_begin(),
1528 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1529 VTLayout.getNumVTableThunks(), RTTI);
1531 VTable->setInitializer(Init);
1533 emitVTableBitSetEntries(Info, RD, VTable);
1537 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1538 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1539 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1540 NeedsVirtualOffset = (NearestVBase != nullptr);
1542 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1543 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1544 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1545 if (!VTableAddressPoint) {
1546 assert(Base.getBase()->getNumVBases() &&
1547 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1549 return VTableAddressPoint;
1552 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1553 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1554 SmallString<256> &Name) {
1555 llvm::raw_svector_ostream Out(Name);
1556 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1559 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1560 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1561 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1562 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1563 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1564 assert(VFTable && "Couldn't find a vftable for the given base?");
1568 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1569 CharUnits VPtrOffset) {
1570 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1571 // shouldn't be used in the given record type. We want to cache this result in
1572 // VFTablesMap, thus a simple zero check is not sufficient.
1573 VFTableIdTy ID(RD, VPtrOffset);
1574 VTablesMapTy::iterator I;
1576 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1580 llvm::GlobalVariable *&VTable = I->second;
1582 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1583 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1585 if (DeferredVFTables.insert(RD).second) {
1586 // We haven't processed this record type before.
1587 // Queue up this v-table for possible deferred emission.
1588 CGM.addDeferredVTable(RD);
1591 // Create all the vftables at once in order to make sure each vftable has
1592 // a unique mangled name.
1593 llvm::StringSet<> ObservedMangledNames;
1594 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1595 SmallString<256> Name;
1596 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1597 if (!ObservedMangledNames.insert(Name.str()).second)
1598 llvm_unreachable("Already saw this mangling before?");
1603 VPtrInfo *const *VFPtrI =
1604 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1605 return VPI->FullOffsetInMDC == VPtrOffset;
1607 if (VFPtrI == VFPtrs.end()) {
1608 VFTablesMap[ID] = nullptr;
1611 VPtrInfo *VFPtr = *VFPtrI;
1613 SmallString<256> VFTableName;
1614 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1616 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1617 bool VFTableComesFromAnotherTU =
1618 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1619 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1620 bool VTableAliasIsRequred =
1621 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1623 if (llvm::GlobalValue *VFTable =
1624 CGM.getModule().getNamedGlobal(VFTableName)) {
1625 VFTablesMap[ID] = VFTable;
1626 return VTableAliasIsRequred
1627 ? cast<llvm::GlobalVariable>(
1628 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1629 : cast<llvm::GlobalVariable>(VFTable);
1632 uint64_t NumVTableSlots =
1633 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1634 .getNumVTableComponents();
1635 llvm::GlobalValue::LinkageTypes VTableLinkage =
1636 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1638 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1640 llvm::ArrayType *VTableType =
1641 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1643 // Create a backing variable for the contents of VTable. The VTable may
1644 // or may not include space for a pointer to RTTI data.
1645 llvm::GlobalValue *VFTable;
1646 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1647 /*isConstant=*/true, VTableLinkage,
1648 /*Initializer=*/nullptr, VTableName);
1649 VTable->setUnnamedAddr(true);
1651 llvm::Comdat *C = nullptr;
1652 if (!VFTableComesFromAnotherTU &&
1653 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1654 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1655 VTableAliasIsRequred)))
1656 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1658 // Only insert a pointer into the VFTable for RTTI data if we are not
1659 // importing it. We never reference the RTTI data directly so there is no
1660 // need to make room for it.
1661 if (VTableAliasIsRequred) {
1662 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1663 llvm::ConstantInt::get(CGM.IntTy, 1)};
1664 // Create a GEP which points just after the first entry in the VFTable,
1665 // this should be the location of the first virtual method.
1666 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1667 VTable->getValueType(), VTable, GEPIndices);
1668 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1669 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1671 C->setSelectionKind(llvm::Comdat::Largest);
1673 VFTable = llvm::GlobalAlias::create(
1674 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1675 VFTableName.str(), VTableGEP, &CGM.getModule());
1676 VFTable->setUnnamedAddr(true);
1678 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1679 // be referencing any RTTI data.
1680 // The GlobalVariable will end up being an appropriate definition of the
1685 VTable->setComdat(C);
1687 if (RD->hasAttr<DLLImportAttr>())
1688 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1689 else if (RD->hasAttr<DLLExportAttr>())
1690 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1692 VFTablesMap[ID] = VFTable;
1696 // Compute the identity of the most derived class whose virtual table is located
1697 // at the given offset into RD.
1698 static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx,
1699 const CXXRecordDecl *RD,
1701 if (Offset.isZero())
1704 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
1705 const CXXRecordDecl *MaxBase = nullptr;
1706 CharUnits MaxBaseOffset;
1707 for (auto &&B : RD->bases()) {
1708 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1709 CharUnits BaseOffset = Layout.getBaseClassOffset(Base);
1710 if (BaseOffset <= Offset && BaseOffset > MaxBaseOffset) {
1712 MaxBaseOffset = BaseOffset;
1715 for (auto &&B : RD->vbases()) {
1716 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1717 CharUnits BaseOffset = Layout.getVBaseClassOffset(Base);
1718 if (BaseOffset <= Offset && BaseOffset > MaxBaseOffset) {
1720 MaxBaseOffset = BaseOffset;
1724 return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset);
1727 // Compute the identity of the most derived class whose virtual table is located
1728 // at the MethodVFTableLocation ML.
1729 static const CXXRecordDecl *
1730 getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD,
1731 MicrosoftVTableContext::MethodVFTableLocation &ML) {
1732 const CXXRecordDecl *RD = ML.VBase;
1734 RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
1736 return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset);
1739 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1743 SourceLocation Loc) {
1744 GD = GD.getCanonicalDecl();
1745 CGBuilderTy &Builder = CGF.Builder;
1747 Ty = Ty->getPointerTo()->getPointerTo();
1749 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1750 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1752 MicrosoftVTableContext::MethodVFTableLocation ML =
1753 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1754 if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
1755 CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML),
1756 VTable, CodeGenFunction::CFITCK_VCall, Loc);
1758 llvm::Value *VFuncPtr =
1759 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1760 return Builder.CreateLoad(VFuncPtr);
1763 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1764 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1765 llvm::Value *This, const CXXMemberCallExpr *CE) {
1766 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1767 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1769 // We have only one destructor in the vftable but can get both behaviors
1770 // by passing an implicit int parameter.
1771 GlobalDecl GD(Dtor, Dtor_Deleting);
1772 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1773 Dtor, StructorType::Deleting);
1774 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1775 llvm::Value *Callee = getVirtualFunctionPointer(
1776 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1778 ASTContext &Context = getContext();
1779 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1780 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1781 DtorType == Dtor_Deleting);
1783 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1784 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1785 ImplicitParam, Context.IntTy, CE,
1786 StructorType::Deleting);
1787 return RV.getScalarVal();
1790 const VBTableGlobals &
1791 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1792 // At this layer, we can key the cache off of a single class, which is much
1793 // easier than caching each vbtable individually.
1794 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1796 std::tie(Entry, Added) =
1797 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1798 VBTableGlobals &VBGlobals = Entry->second;
1802 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1803 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1805 // Cache the globals for all vbtables so we don't have to recompute the
1807 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1808 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1809 E = VBGlobals.VBTables->end();
1811 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1817 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1818 const CXXMethodDecl *MD,
1819 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1820 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1821 "can't form pointers to ctors or virtual dtors");
1823 // Calculate the mangled name.
1824 SmallString<256> ThunkName;
1825 llvm::raw_svector_ostream Out(ThunkName);
1826 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1829 // If the thunk has been generated previously, just return it.
1830 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1831 return cast<llvm::Function>(GV);
1833 // Create the llvm::Function.
1834 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1835 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1836 llvm::Function *ThunkFn =
1837 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1838 ThunkName.str(), &CGM.getModule());
1839 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1841 ThunkFn->setLinkage(MD->isExternallyVisible()
1842 ? llvm::GlobalValue::LinkOnceODRLinkage
1843 : llvm::GlobalValue::InternalLinkage);
1844 if (MD->isExternallyVisible())
1845 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1847 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1848 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1850 // Add the "thunk" attribute so that LLVM knows that the return type is
1851 // meaningless. These thunks can be used to call functions with differing
1852 // return types, and the caller is required to cast the prototype
1853 // appropriately to extract the correct value.
1854 ThunkFn->addFnAttr("thunk");
1856 // These thunks can be compared, so they are not unnamed.
1857 ThunkFn->setUnnamedAddr(false);
1860 CodeGenFunction CGF(CGM);
1861 CGF.CurGD = GlobalDecl(MD);
1862 CGF.CurFuncIsThunk = true;
1864 // Build FunctionArgs, but only include the implicit 'this' parameter
1866 FunctionArgList FunctionArgs;
1867 buildThisParam(CGF, FunctionArgs);
1869 // Start defining the function.
1870 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1871 FunctionArgs, MD->getLocation(), SourceLocation());
1874 // Load the vfptr and then callee from the vftable. The callee should have
1875 // adjusted 'this' so that the vfptr is at offset zero.
1876 llvm::Value *VTable = CGF.GetVTablePtr(
1877 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1878 llvm::Value *VFuncPtr =
1879 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1880 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1882 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1887 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1888 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1889 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1890 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1891 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1892 if (GV->isDeclaration())
1893 emitVBTableDefinition(*VBT, RD, GV);
1897 llvm::GlobalVariable *
1898 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1899 llvm::GlobalVariable::LinkageTypes Linkage) {
1900 SmallString<256> OutName;
1901 llvm::raw_svector_ostream Out(OutName);
1902 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1904 StringRef Name = OutName.str();
1906 llvm::ArrayType *VBTableType =
1907 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1909 assert(!CGM.getModule().getNamedGlobal(Name) &&
1910 "vbtable with this name already exists: mangling bug?");
1911 llvm::GlobalVariable *GV =
1912 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1913 GV->setUnnamedAddr(true);
1915 if (RD->hasAttr<DLLImportAttr>())
1916 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1917 else if (RD->hasAttr<DLLExportAttr>())
1918 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1920 if (!GV->hasExternalLinkage())
1921 emitVBTableDefinition(VBT, RD, GV);
1926 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1927 const CXXRecordDecl *RD,
1928 llvm::GlobalVariable *GV) const {
1929 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1931 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1932 "should only emit vbtables for classes with vbtables");
1934 const ASTRecordLayout &BaseLayout =
1935 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1936 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1938 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1941 // The offset from ReusingBase's vbptr to itself always leads.
1942 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1943 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1945 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1946 for (const auto &I : ReusingBase->vbases()) {
1947 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1948 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1949 assert(!Offset.isNegative());
1951 // Make it relative to the subobject vbptr.
1952 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1953 if (VBT.getVBaseWithVPtr())
1954 CompleteVBPtrOffset +=
1955 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1956 Offset -= CompleteVBPtrOffset;
1958 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1959 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1960 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1963 assert(Offsets.size() ==
1964 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1965 ->getElementType())->getNumElements());
1966 llvm::ArrayType *VBTableType =
1967 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1968 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1969 GV->setInitializer(Init);
1972 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1974 const ThisAdjustment &TA) {
1978 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1980 if (!TA.Virtual.isEmpty()) {
1981 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1982 // Adjust the this argument based on the vtordisp value.
1983 llvm::Value *VtorDispPtr =
1984 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1986 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1987 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1988 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1990 if (TA.Virtual.Microsoft.VBPtrOffset) {
1991 // If the final overrider is defined in a virtual base other than the one
1992 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1993 // the vbtable of the derived class.
1994 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1995 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1997 llvm::Value *VBaseOffset =
1998 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1999 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
2000 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2004 if (TA.NonVirtual) {
2005 // Non-virtual adjustment might result in a pointer outside the allocated
2006 // object, e.g. if the final overrider class is laid out after the virtual
2007 // base that declares a method in the most derived class.
2008 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
2011 // Don't need to bitcast back, the call CodeGen will handle this.
2016 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
2017 const ReturnAdjustment &RA) {
2021 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
2023 if (RA.Virtual.Microsoft.VBIndex) {
2024 assert(RA.Virtual.Microsoft.VBIndex > 0);
2025 const ASTContext &Context = getContext();
2026 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
2028 llvm::Value *VBaseOffset =
2029 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
2030 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
2031 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2035 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
2037 // Cast back to the original type.
2038 return CGF.Builder.CreateBitCast(V, Ret->getType());
2041 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
2042 QualType elementType) {
2043 // Microsoft seems to completely ignore the possibility of a
2044 // two-argument usual deallocation function.
2045 return elementType.isDestructedType();
2048 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
2049 // Microsoft seems to completely ignore the possibility of a
2050 // two-argument usual deallocation function.
2051 return expr->getAllocatedType().isDestructedType();
2054 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2055 // The array cookie is always a size_t; we then pad that out to the
2056 // alignment of the element type.
2057 ASTContext &Ctx = getContext();
2058 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2059 Ctx.getTypeAlignInChars(type));
2062 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2063 llvm::Value *allocPtr,
2064 CharUnits cookieSize) {
2065 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
2066 llvm::Value *numElementsPtr =
2067 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
2068 return CGF.Builder.CreateLoad(numElementsPtr);
2071 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2072 llvm::Value *newPtr,
2073 llvm::Value *numElements,
2074 const CXXNewExpr *expr,
2075 QualType elementType) {
2076 assert(requiresArrayCookie(expr));
2078 // The size of the cookie.
2079 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2081 // Compute an offset to the cookie.
2082 llvm::Value *cookiePtr = newPtr;
2084 // Write the number of elements into the appropriate slot.
2085 unsigned AS = newPtr->getType()->getPointerAddressSpace();
2086 llvm::Value *numElementsPtr
2087 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
2088 CGF.Builder.CreateStore(numElements, numElementsPtr);
2090 // Finally, compute a pointer to the actual data buffer by skipping
2091 // over the cookie completely.
2092 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
2093 cookieSize.getQuantity());
2096 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2097 llvm::Constant *Dtor,
2098 llvm::Constant *Addr) {
2099 // Create a function which calls the destructor.
2100 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2102 // extern "C" int __tlregdtor(void (*f)(void));
2103 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2104 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2106 llvm::Constant *TLRegDtor =
2107 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
2108 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2109 TLRegDtorFn->setDoesNotThrow();
2111 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2114 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2115 llvm::Constant *Dtor,
2116 llvm::Constant *Addr) {
2118 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2120 // The default behavior is to use atexit.
2121 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2124 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2126 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
2128 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2129 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
2130 // This will create a GV in the .CRT$XDU section. It will point to our
2131 // initialization function. The CRT will call all of these function
2132 // pointers at start-up time and, eventually, at thread-creation time.
2133 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2134 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2135 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2136 llvm::GlobalVariable::InternalLinkage, InitFunc,
2137 Twine(InitFunc->getName(), "$initializer$"));
2138 InitFuncPtr->setSection(".CRT$XDU");
2139 // This variable has discardable linkage, we have to add it to @llvm.used to
2140 // ensure it won't get discarded.
2141 CGM.addUsedGlobal(InitFuncPtr);
2145 std::vector<llvm::Function *> NonComdatInits;
2146 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2147 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
2148 llvm::Function *F = CXXThreadLocalInits[I];
2150 // If the GV is already in a comdat group, then we have to join it.
2151 if (llvm::Comdat *C = GV->getComdat())
2152 AddToXDU(F)->setComdat(C);
2154 NonComdatInits.push_back(F);
2157 if (!NonComdatInits.empty()) {
2158 llvm::FunctionType *FTy =
2159 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2160 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2161 FTy, "__tls_init", SourceLocation(),
2163 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2169 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2171 QualType LValType) {
2172 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2176 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2177 StringRef VarName("_Init_thread_epoch");
2178 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2180 auto *GV = new llvm::GlobalVariable(
2181 CGM.getModule(), CGM.IntTy,
2182 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2183 /*Initializer=*/nullptr, VarName,
2184 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2185 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2189 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2190 llvm::FunctionType *FTy =
2191 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2192 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2193 return CGM.CreateRuntimeFunction(
2194 FTy, "_Init_thread_header",
2195 llvm::AttributeSet::get(CGM.getLLVMContext(),
2196 llvm::AttributeSet::FunctionIndex,
2197 llvm::Attribute::NoUnwind));
2200 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2201 llvm::FunctionType *FTy =
2202 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2203 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2204 return CGM.CreateRuntimeFunction(
2205 FTy, "_Init_thread_footer",
2206 llvm::AttributeSet::get(CGM.getLLVMContext(),
2207 llvm::AttributeSet::FunctionIndex,
2208 llvm::Attribute::NoUnwind));
2211 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2212 llvm::FunctionType *FTy =
2213 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2214 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2215 return CGM.CreateRuntimeFunction(
2216 FTy, "_Init_thread_abort",
2217 llvm::AttributeSet::get(CGM.getLLVMContext(),
2218 llvm::AttributeSet::FunctionIndex,
2219 llvm::Attribute::NoUnwind));
2223 struct ResetGuardBit : EHScopeStack::Cleanup {
2224 llvm::GlobalVariable *Guard;
2226 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2227 : Guard(Guard), GuardNum(GuardNum) {}
2229 void Emit(CodeGenFunction &CGF, Flags flags) override {
2230 // Reset the bit in the mask so that the static variable may be
2232 CGBuilderTy &Builder = CGF.Builder;
2233 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2234 llvm::ConstantInt *Mask =
2235 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2236 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2240 struct CallInitThreadAbort : EHScopeStack::Cleanup {
2241 llvm::GlobalVariable *Guard;
2242 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2244 void Emit(CodeGenFunction &CGF, Flags flags) override {
2245 // Calling _Init_thread_abort will reset the guard's state.
2246 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2251 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2252 llvm::GlobalVariable *GV,
2254 // MSVC only uses guards for static locals.
2255 if (!D.isStaticLocal()) {
2256 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2257 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2258 llvm::Function *F = CGF.CurFn;
2259 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2260 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2261 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2265 bool ThreadlocalStatic = D.getTLSKind();
2266 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2268 // Thread-safe static variables which aren't thread-specific have a
2269 // per-variable guard.
2270 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2272 CGBuilderTy &Builder = CGF.Builder;
2273 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2274 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2276 // Get the guard variable for this function if we have one already.
2277 GuardInfo *GI = nullptr;
2278 if (ThreadlocalStatic)
2279 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2280 else if (!ThreadsafeStatic)
2281 GI = &GuardVariableMap[D.getDeclContext()];
2283 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2285 if (D.isExternallyVisible()) {
2286 // Externally visible variables have to be numbered in Sema to properly
2287 // handle unreachable VarDecls.
2288 GuardNum = getContext().getStaticLocalNumber(&D);
2289 assert(GuardNum > 0);
2291 } else if (HasPerVariableGuard) {
2292 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2294 // Non-externally visible variables are numbered here in CodeGen.
2295 GuardNum = GI->BitIndex++;
2298 if (!HasPerVariableGuard && GuardNum >= 32) {
2299 if (D.isExternallyVisible())
2300 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2306 // Mangle the name for the guard.
2307 SmallString<256> GuardName;
2309 llvm::raw_svector_ostream Out(GuardName);
2310 if (HasPerVariableGuard)
2311 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2314 getMangleContext().mangleStaticGuardVariable(&D, Out);
2318 // Create the guard variable with a zero-initializer. Just absorb linkage,
2319 // visibility and dll storage class from the guarded variable.
2321 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2322 GV->getLinkage(), Zero, GuardName.str());
2323 GuardVar->setVisibility(GV->getVisibility());
2324 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2325 if (GuardVar->isWeakForLinker())
2326 GuardVar->setComdat(
2327 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2329 GuardVar->setThreadLocal(true);
2330 if (GI && !HasPerVariableGuard)
2331 GI->Guard = GuardVar;
2334 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2335 "static local from the same function had different linkage");
2337 if (!HasPerVariableGuard) {
2338 // Pseudo code for the test:
2339 // if (!(GuardVar & MyGuardBit)) {
2340 // GuardVar |= MyGuardBit;
2341 // ... initialize the object ...;
2344 // Test our bit from the guard variable.
2345 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2346 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2347 llvm::Value *IsInitialized =
2348 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2349 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2350 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2351 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2353 // Set our bit in the guard variable and emit the initializer and add a global
2354 // destructor if appropriate.
2355 CGF.EmitBlock(InitBlock);
2356 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2357 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2358 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2359 CGF.PopCleanupBlock();
2360 Builder.CreateBr(EndBlock);
2363 CGF.EmitBlock(EndBlock);
2365 // Pseudo code for the test:
2366 // if (TSS > _Init_thread_epoch) {
2367 // _Init_thread_header(&TSS);
2369 // ... initialize the object ...;
2370 // _Init_thread_footer(&TSS);
2374 // The algorithm is almost identical to what can be found in the appendix
2377 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2379 // This BasicBLock determines whether or not we have any work to do.
2380 llvm::LoadInst *FirstGuardLoad =
2381 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2382 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2383 llvm::LoadInst *InitThreadEpoch =
2384 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2385 llvm::Value *IsUninitialized =
2386 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2387 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2388 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2389 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2391 // This BasicBlock attempts to determine whether or not this thread is
2392 // responsible for doing the initialization.
2393 CGF.EmitBlock(AttemptInitBlock);
2394 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2395 llvm::LoadInst *SecondGuardLoad =
2396 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2397 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2398 llvm::Value *ShouldDoInit =
2399 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2400 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2401 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2403 // Ok, we ended up getting selected as the initializing thread.
2404 CGF.EmitBlock(InitBlock);
2405 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2406 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2407 CGF.PopCleanupBlock();
2408 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2409 Builder.CreateBr(EndBlock);
2411 CGF.EmitBlock(EndBlock);
2415 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2416 // Null-ness for function memptrs only depends on the first field, which is
2417 // the function pointer. The rest don't matter, so we can zero initialize.
2418 if (MPT->isMemberFunctionPointer())
2421 // The virtual base adjustment field is always -1 for null, so if we have one
2422 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2423 // valid field offset.
2424 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2425 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2426 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2427 RD->nullFieldOffsetIsZero());
2431 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2432 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2433 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2434 llvm::SmallVector<llvm::Type *, 4> fields;
2435 if (MPT->isMemberFunctionPointer())
2436 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2438 fields.push_back(CGM.IntTy); // FieldOffset
2440 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2442 fields.push_back(CGM.IntTy);
2443 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2444 fields.push_back(CGM.IntTy);
2445 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2446 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2448 if (fields.size() == 1)
2450 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2453 void MicrosoftCXXABI::
2454 GetNullMemberPointerFields(const MemberPointerType *MPT,
2455 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2456 assert(fields.empty());
2457 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2458 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2459 if (MPT->isMemberFunctionPointer()) {
2460 // FunctionPointerOrVirtualThunk
2461 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2463 if (RD->nullFieldOffsetIsZero())
2464 fields.push_back(getZeroInt()); // FieldOffset
2466 fields.push_back(getAllOnesInt()); // FieldOffset
2469 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2471 fields.push_back(getZeroInt());
2472 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2473 fields.push_back(getZeroInt());
2474 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2475 fields.push_back(getAllOnesInt());
2479 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2480 llvm::SmallVector<llvm::Constant *, 4> fields;
2481 GetNullMemberPointerFields(MPT, fields);
2482 if (fields.size() == 1)
2484 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2485 assert(Res->getType() == ConvertMemberPointerType(MPT));
2490 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2491 bool IsMemberFunction,
2492 const CXXRecordDecl *RD,
2493 CharUnits NonVirtualBaseAdjustment,
2494 unsigned VBTableIndex) {
2495 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2497 // Single inheritance class member pointer are represented as scalars instead
2499 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2502 llvm::SmallVector<llvm::Constant *, 4> fields;
2503 fields.push_back(FirstField);
2505 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2506 fields.push_back(llvm::ConstantInt::get(
2507 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2509 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2510 CharUnits Offs = CharUnits::Zero();
2512 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2513 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2516 // The rest of the fields are adjusted by conversions to a more derived class.
2517 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2518 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2520 return llvm::ConstantStruct::getAnon(fields);
2524 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2526 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2527 if (RD->getMSInheritanceModel() ==
2528 MSInheritanceAttr::Keyword_virtual_inheritance)
2529 offset -= getContext().getOffsetOfBaseWithVBPtr(RD);
2530 llvm::Constant *FirstField =
2531 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2532 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2533 CharUnits::Zero(), /*VBTableIndex=*/0);
2536 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2538 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2539 const ValueDecl *MPD = MP.getMemberPointerDecl();
2541 return EmitNullMemberPointer(DstTy);
2543 ASTContext &Ctx = getContext();
2544 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2547 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2548 C = EmitMemberFunctionPointer(MD);
2550 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2551 C = EmitMemberDataPointer(DstTy, FieldOffset);
2554 if (!MemberPointerPath.empty()) {
2555 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2556 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2557 const MemberPointerType *SrcTy =
2558 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2559 ->castAs<MemberPointerType>();
2561 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2562 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2563 const CXXRecordDecl *PrevRD = SrcRD;
2564 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2565 const CXXRecordDecl *Base = nullptr;
2566 const CXXRecordDecl *Derived = nullptr;
2567 if (DerivedMember) {
2574 for (const CXXBaseSpecifier &BS : Derived->bases())
2575 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2576 Base->getCanonicalDecl())
2577 DerivedToBasePath.push_back(&BS);
2580 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2582 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2583 : CK_BaseToDerivedMemberPointer;
2584 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2585 DerivedToBasePath.end(), C);
2591 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2592 assert(MD->isInstance() && "Member function must not be static!");
2594 MD = MD->getCanonicalDecl();
2595 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2596 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2597 CodeGenTypes &Types = CGM.getTypes();
2599 unsigned VBTableIndex = 0;
2600 llvm::Constant *FirstField;
2601 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2602 if (!MD->isVirtual()) {
2604 // Check whether the function has a computable LLVM signature.
2605 if (Types.isFuncTypeConvertible(FPT)) {
2606 // The function has a computable LLVM signature; use the correct type.
2607 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2609 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2610 // function type is incomplete.
2613 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2615 auto &VTableContext = CGM.getMicrosoftVTableContext();
2616 MicrosoftVTableContext::MethodVFTableLocation ML =
2617 VTableContext.getMethodVFTableLocation(MD);
2618 FirstField = EmitVirtualMemPtrThunk(MD, ML);
2619 // Include the vfptr adjustment if the method is in a non-primary vftable.
2620 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2622 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2625 if (VBTableIndex == 0 &&
2626 RD->getMSInheritanceModel() ==
2627 MSInheritanceAttr::Keyword_virtual_inheritance)
2628 NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD);
2630 // The rest of the fields are common with data member pointers.
2631 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2632 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2633 NonVirtualBaseAdjustment, VBTableIndex);
2636 /// Member pointers are the same if they're either bitwise identical *or* both
2637 /// null. Null-ness for function members is determined by the first field,
2638 /// while for data member pointers we must compare all fields.
2640 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2643 const MemberPointerType *MPT,
2645 CGBuilderTy &Builder = CGF.Builder;
2647 // Handle != comparisons by switching the sense of all boolean operations.
2648 llvm::ICmpInst::Predicate Eq;
2649 llvm::Instruction::BinaryOps And, Or;
2651 Eq = llvm::ICmpInst::ICMP_NE;
2652 And = llvm::Instruction::Or;
2653 Or = llvm::Instruction::And;
2655 Eq = llvm::ICmpInst::ICMP_EQ;
2656 And = llvm::Instruction::And;
2657 Or = llvm::Instruction::Or;
2660 // If this is a single field member pointer (single inheritance), this is a
2662 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2663 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2664 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2666 return Builder.CreateICmp(Eq, L, R);
2668 // Compare the first field.
2669 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2670 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2671 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2673 // Compare everything other than the first field.
2674 llvm::Value *Res = nullptr;
2675 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2676 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2677 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2678 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2679 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2681 Res = Builder.CreateBinOp(And, Res, Cmp);
2686 // Check if the first field is 0 if this is a function pointer.
2687 if (MPT->isMemberFunctionPointer()) {
2688 // (l1 == r1 && ...) || l0 == 0
2689 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2690 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2691 Res = Builder.CreateBinOp(Or, Res, IsZero);
2694 // Combine the comparison of the first field, which must always be true for
2695 // this comparison to succeeed.
2696 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2700 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2701 llvm::Value *MemPtr,
2702 const MemberPointerType *MPT) {
2703 CGBuilderTy &Builder = CGF.Builder;
2704 llvm::SmallVector<llvm::Constant *, 4> fields;
2705 // We only need one field for member functions.
2706 if (MPT->isMemberFunctionPointer())
2707 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2709 GetNullMemberPointerFields(MPT, fields);
2710 assert(!fields.empty());
2711 llvm::Value *FirstField = MemPtr;
2712 if (MemPtr->getType()->isStructTy())
2713 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2714 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2716 // For function member pointers, we only need to test the function pointer
2717 // field. The other fields if any can be garbage.
2718 if (MPT->isMemberFunctionPointer())
2721 // Otherwise, emit a series of compares and combine the results.
2722 for (int I = 1, E = fields.size(); I < E; ++I) {
2723 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2724 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2725 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2730 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2731 llvm::Constant *Val) {
2732 // Function pointers are null if the pointer in the first field is null.
2733 if (MPT->isMemberFunctionPointer()) {
2734 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2735 Val->getAggregateElement(0U) : Val;
2736 return FirstField->isNullValue();
2739 // If it's not a function pointer and it's zero initializable, we can easily
2741 if (isZeroInitializable(MPT) && Val->isNullValue())
2744 // Otherwise, break down all the fields for comparison. Hopefully these
2745 // little Constants are reused, while a big null struct might not be.
2746 llvm::SmallVector<llvm::Constant *, 4> Fields;
2747 GetNullMemberPointerFields(MPT, Fields);
2748 if (Fields.size() == 1) {
2749 assert(Val->getType()->isIntegerTy());
2750 return Val == Fields[0];
2754 for (I = 0, E = Fields.size(); I != E; ++I) {
2755 if (Val->getAggregateElement(I) != Fields[I])
2762 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2764 llvm::Value *VBPtrOffset,
2765 llvm::Value *VBTableOffset,
2766 llvm::Value **VBPtrOut) {
2767 CGBuilderTy &Builder = CGF.Builder;
2768 // Load the vbtable pointer from the vbptr in the instance.
2769 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2770 llvm::Value *VBPtr =
2771 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2772 if (VBPtrOut) *VBPtrOut = VBPtr;
2773 VBPtr = Builder.CreateBitCast(VBPtr,
2774 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2775 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2777 // Translate from byte offset to table index. It improves analyzability.
2778 llvm::Value *VBTableIndex = Builder.CreateAShr(
2779 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2780 "vbtindex", /*isExact=*/true);
2782 // Load an i32 offset from the vb-table.
2783 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2784 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2785 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2788 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2790 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2791 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2792 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2793 CGBuilderTy &Builder = CGF.Builder;
2794 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2795 llvm::BasicBlock *OriginalBB = nullptr;
2796 llvm::BasicBlock *SkipAdjustBB = nullptr;
2797 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2799 // In the unspecified inheritance model, there might not be a vbtable at all,
2800 // in which case we need to skip the virtual base lookup. If there is a
2801 // vbtable, the first entry is a no-op entry that gives back the original
2802 // base, so look for a virtual base adjustment offset of zero.
2804 OriginalBB = Builder.GetInsertBlock();
2805 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2806 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2807 llvm::Value *IsVirtual =
2808 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2810 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2811 CGF.EmitBlock(VBaseAdjustBB);
2814 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2815 // know the vbptr offset.
2817 CharUnits offs = CharUnits::Zero();
2818 if (!RD->hasDefinition()) {
2819 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2820 unsigned DiagID = Diags.getCustomDiagID(
2821 DiagnosticsEngine::Error,
2822 "member pointer representation requires a "
2823 "complete class type for %0 to perform this expression");
2824 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2825 } else if (RD->getNumVBases())
2826 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2827 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2829 llvm::Value *VBPtr = nullptr;
2830 llvm::Value *VBaseOffs =
2831 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2832 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2834 // Merge control flow with the case where we didn't have to adjust.
2835 if (VBaseAdjustBB) {
2836 Builder.CreateBr(SkipAdjustBB);
2837 CGF.EmitBlock(SkipAdjustBB);
2838 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2839 Phi->addIncoming(Base, OriginalBB);
2840 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2843 return AdjustedBase;
2846 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2847 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2848 const MemberPointerType *MPT) {
2849 assert(MPT->isMemberDataPointer());
2850 unsigned AS = Base->getType()->getPointerAddressSpace();
2852 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2853 CGBuilderTy &Builder = CGF.Builder;
2854 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2855 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2857 // Extract the fields we need, regardless of model. We'll apply them if we
2859 llvm::Value *FieldOffset = MemPtr;
2860 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2861 llvm::Value *VBPtrOffset = nullptr;
2862 if (MemPtr->getType()->isStructTy()) {
2863 // We need to extract values.
2865 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2866 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2867 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2868 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2869 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2872 if (VirtualBaseAdjustmentOffset) {
2873 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2878 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2880 // Apply the offset, which we assume is non-null.
2882 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2884 // Cast the address to the appropriate pointer type, adopting the address
2885 // space of the base pointer.
2886 return Builder.CreateBitCast(Addr, PType);
2890 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2893 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2894 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2895 E->getCastKind() == CK_ReinterpretMemberPointer);
2897 // Use constant emission if we can.
2898 if (isa<llvm::Constant>(Src))
2899 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2901 // We may be adding or dropping fields from the member pointer, so we need
2902 // both types and the inheritance models of both records.
2903 const MemberPointerType *SrcTy =
2904 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2905 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2906 bool IsFunc = SrcTy->isMemberFunctionPointer();
2908 // If the classes use the same null representation, reinterpret_cast is a nop.
2909 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2910 if (IsReinterpret && IsFunc)
2913 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2914 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2915 if (IsReinterpret &&
2916 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2919 CGBuilderTy &Builder = CGF.Builder;
2921 // Branch past the conversion if Src is null.
2922 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2923 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2925 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2926 // pointer value of the destination type.
2927 if (IsReinterpret) {
2928 // For reinterpret casts, sema ensures that src and dst are both functions
2929 // or data and have the same size, which means the LLVM types should match.
2930 assert(Src->getType() == DstNull->getType());
2931 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2934 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2935 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2936 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2937 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2938 CGF.EmitBlock(ConvertBB);
2940 llvm::Value *Dst = EmitNonNullMemberPointerConversion(
2941 SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src,
2944 Builder.CreateBr(ContinueBB);
2946 // In the continuation, choose between DstNull and Dst.
2947 CGF.EmitBlock(ContinueBB);
2948 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2949 Phi->addIncoming(DstNull, OriginalBB);
2950 Phi->addIncoming(Dst, ConvertBB);
2954 llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion(
2955 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
2956 CastExpr::path_const_iterator PathBegin,
2957 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
2958 CGBuilderTy &Builder) {
2959 const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2960 const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2961 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2962 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2963 bool IsFunc = SrcTy->isMemberFunctionPointer();
2964 bool IsConstant = isa<llvm::Constant>(Src);
2967 llvm::Value *FirstField = Src;
2968 llvm::Value *NonVirtualBaseAdjustment = getZeroInt();
2969 llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt();
2970 llvm::Value *VBPtrOffset = getZeroInt();
2971 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2972 // We need to extract values.
2974 FirstField = Builder.CreateExtractValue(Src, I++);
2975 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2976 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2977 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2978 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2979 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2980 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2983 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
2984 const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy;
2985 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
2987 // For data pointers, we adjust the field offset directly. For functions, we
2988 // have a separate field.
2989 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2991 // The virtual inheritance model has a quirk: the virtual base table is always
2992 // referenced when dereferencing a member pointer even if the member pointer
2993 // is non-virtual. This is accounted for by adjusting the non-virtual offset
2994 // to point backwards to the top of the MDC from the first VBase. Undo this
2995 // adjustment to normalize the member pointer.
2996 llvm::Value *SrcVBIndexEqZero =
2997 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
2998 if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
2999 if (int64_t SrcOffsetToFirstVBase =
3000 getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) {
3001 llvm::Value *UndoSrcAdjustment = Builder.CreateSelect(
3003 llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase),
3005 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment);
3009 // A non-zero vbindex implies that we are dealing with a source member in a
3010 // floating virtual base in addition to some non-virtual offset. If the
3011 // vbindex is zero, we are dealing with a source that exists in a non-virtual,
3012 // fixed, base. The difference between these two cases is that the vbindex +
3013 // nvoffset *always* point to the member regardless of what context they are
3014 // evaluated in so long as the vbindex is adjusted. A member inside a fixed
3015 // base requires explicit nv adjustment.
3016 llvm::Constant *BaseClassOffset = llvm::ConstantInt::get(
3018 CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd)
3021 llvm::Value *NVDisp;
3022 if (IsDerivedToBase)
3023 NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj");
3025 NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj");
3027 NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt());
3029 // Update the vbindex to an appropriate value in the destination because
3030 // SrcRD's vbtable might not be a strict prefix of the one in DstRD.
3031 llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero;
3032 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) &&
3033 MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) {
3034 if (llvm::GlobalVariable *VDispMap =
3035 getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) {
3036 llvm::Value *VBIndex = Builder.CreateExactUDiv(
3037 VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4));
3039 llvm::Constant *Mapping = VDispMap->getInitializer();
3040 VirtualBaseAdjustmentOffset =
3041 Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex));
3043 llvm::Value *Idxs[] = {getZeroInt(), VBIndex};
3044 VirtualBaseAdjustmentOffset =
3045 Builder.CreateLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs));
3049 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3053 // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize
3054 // it to the offset of the vbptr.
3055 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) {
3056 llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get(
3058 getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity());
3060 Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset);
3063 // Likewise, apply a similar adjustment so that dereferencing the member
3064 // pointer correctly accounts for the distance between the start of the first
3065 // virtual base and the top of the MDC.
3066 if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3067 if (int64_t DstOffsetToFirstVBase =
3068 getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) {
3069 llvm::Value *DoDstAdjustment = Builder.CreateSelect(
3071 llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase),
3073 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment);
3077 // Recompose dst from the null struct and the adjusted fields from src.
3079 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
3082 Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy));
3084 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
3085 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3086 Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++);
3087 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3088 Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++);
3089 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3090 Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++);
3096 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
3097 llvm::Constant *Src) {
3098 const MemberPointerType *SrcTy =
3099 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3100 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3102 CastKind CK = E->getCastKind();
3104 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
3105 E->path_end(), Src);
3108 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
3109 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3110 CastExpr::path_const_iterator PathBegin,
3111 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
3112 assert(CK == CK_DerivedToBaseMemberPointer ||
3113 CK == CK_BaseToDerivedMemberPointer ||
3114 CK == CK_ReinterpretMemberPointer);
3115 // If src is null, emit a new null for dst. We can't return src because dst
3116 // might have a new representation.
3117 if (MemberPointerConstantIsNull(SrcTy, Src))
3118 return EmitNullMemberPointer(DstTy);
3120 // We don't need to do anything for reinterpret_casts of non-null member
3121 // pointers. We should only get here when the two type representations have
3123 if (CK == CK_ReinterpretMemberPointer)
3126 CGBuilderTy Builder(CGM.getLLVMContext());
3127 auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion(
3128 SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder));
3133 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3134 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
3135 llvm::Value *MemPtr, const MemberPointerType *MPT) {
3136 assert(MPT->isMemberFunctionPointer());
3137 const FunctionProtoType *FPT =
3138 MPT->getPointeeType()->castAs<FunctionProtoType>();
3139 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3140 llvm::FunctionType *FTy =
3141 CGM.getTypes().GetFunctionType(
3142 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
3143 CGBuilderTy &Builder = CGF.Builder;
3145 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3147 // Extract the fields we need, regardless of model. We'll apply them if we
3149 llvm::Value *FunctionPointer = MemPtr;
3150 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3151 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3152 llvm::Value *VBPtrOffset = nullptr;
3153 if (MemPtr->getType()->isStructTy()) {
3154 // We need to extract values.
3156 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3157 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3158 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3159 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3160 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3161 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3162 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3165 if (VirtualBaseAdjustmentOffset) {
3166 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
3170 if (NonVirtualBaseAdjustment) {
3171 // Apply the adjustment and cast back to the original struct type.
3172 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
3173 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3174 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
3177 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3180 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3181 return new MicrosoftCXXABI(CGM);
3184 // MS RTTI Overview:
3185 // The run time type information emitted by cl.exe contains 5 distinct types of
3186 // structures. Many of them reference each other.
3188 // TypeInfo: Static classes that are returned by typeid.
3190 // CompleteObjectLocator: Referenced by vftables. They contain information
3191 // required for dynamic casting, including OffsetFromTop. They also contain
3192 // a reference to the TypeInfo for the type and a reference to the
3193 // CompleteHierarchyDescriptor for the type.
3195 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3196 // Used during dynamic_cast to walk a class hierarchy. References a base
3197 // class array and the size of said array.
3199 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3200 // somewhat of a misnomer because the most derived class is also in the list
3201 // as well as multiple copies of virtual bases (if they occur multiple times
3202 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3203 // every path in the hierarchy, in pre-order depth first order. Note, we do
3204 // not declare a specific llvm type for BaseClassArray, it's merely an array
3205 // of BaseClassDescriptor pointers.
3207 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3208 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3209 // BaseClassArray is. It contains information about a class within a
3210 // hierarchy such as: is this base is ambiguous and what is its offset in the
3211 // vbtable. The names of the BaseClassDescriptors have all of their fields
3212 // mangled into them so they can be aggressively deduplicated by the linker.
3214 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3215 StringRef MangledName("\01??_7type_info@@6B@");
3216 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3218 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3220 llvm::GlobalVariable::ExternalLinkage,
3221 /*Initializer=*/nullptr, MangledName);
3226 /// \brief A Helper struct that stores information about a class in a class
3227 /// hierarchy. The information stored in these structs struct is used during
3228 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3229 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3230 // implicit depth first pre-order tree connectivity. getFirstChild and
3231 // getNextSibling allow us to walk the tree efficiently.
3232 struct MSRTTIClass {
3234 IsPrivateOnPath = 1 | 8,
3238 HasHierarchyDescriptor = 64
3240 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3241 uint32_t initialize(const MSRTTIClass *Parent,
3242 const CXXBaseSpecifier *Specifier);
3244 MSRTTIClass *getFirstChild() { return this + 1; }
3245 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3246 return Child + 1 + Child->NumBases;
3249 const CXXRecordDecl *RD, *VirtualRoot;
3250 uint32_t Flags, NumBases, OffsetInVBase;
3253 /// \brief Recursively initialize the base class array.
3254 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3255 const CXXBaseSpecifier *Specifier) {
3256 Flags = HasHierarchyDescriptor;
3258 VirtualRoot = nullptr;
3261 if (Specifier->getAccessSpecifier() != AS_public)
3262 Flags |= IsPrivate | IsPrivateOnPath;
3263 if (Specifier->isVirtual()) {
3268 if (Parent->Flags & IsPrivateOnPath)
3269 Flags |= IsPrivateOnPath;
3270 VirtualRoot = Parent->VirtualRoot;
3271 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3272 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3276 MSRTTIClass *Child = getFirstChild();
3277 for (const CXXBaseSpecifier &Base : RD->bases()) {
3278 NumBases += Child->initialize(this, &Base) + 1;
3279 Child = getNextChild(Child);
3284 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3285 switch (Ty->getLinkage()) {
3287 case InternalLinkage:
3288 case UniqueExternalLinkage:
3289 return llvm::GlobalValue::InternalLinkage;
3291 case VisibleNoLinkage:
3292 case ExternalLinkage:
3293 return llvm::GlobalValue::LinkOnceODRLinkage;
3295 llvm_unreachable("Invalid linkage!");
3298 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3299 /// calls to the module and information about the most derived class in a
3301 struct MSRTTIBuilder {
3303 HasBranchingHierarchy = 1,
3304 HasVirtualBranchingHierarchy = 2,
3305 HasAmbiguousBases = 4
3308 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3309 : CGM(ABI.CGM), Context(CGM.getContext()),
3310 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3311 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3314 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3315 llvm::GlobalVariable *
3316 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3317 llvm::GlobalVariable *getClassHierarchyDescriptor();
3318 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3321 ASTContext &Context;
3322 llvm::LLVMContext &VMContext;
3323 llvm::Module &Module;
3324 const CXXRecordDecl *RD;
3325 llvm::GlobalVariable::LinkageTypes Linkage;
3326 MicrosoftCXXABI &ABI;
3331 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3333 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3334 const CXXRecordDecl *RD) {
3335 Classes.push_back(MSRTTIClass(RD));
3336 for (const CXXBaseSpecifier &Base : RD->bases())
3337 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3340 /// \brief Find ambiguity among base classes.
3342 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3343 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3344 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3345 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3346 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3347 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3348 !VirtualBases.insert(Class->RD).second) {
3349 Class = MSRTTIClass::getNextChild(Class);
3352 if (!UniqueBases.insert(Class->RD).second)
3353 AmbiguousBases.insert(Class->RD);
3356 if (AmbiguousBases.empty())
3358 for (MSRTTIClass &Class : Classes)
3359 if (AmbiguousBases.count(Class.RD))
3360 Class.Flags |= MSRTTIClass::IsAmbiguous;
3363 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3364 SmallString<256> MangledName;
3366 llvm::raw_svector_ostream Out(MangledName);
3367 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3370 // Check to see if we've already declared this ClassHierarchyDescriptor.
3371 if (auto CHD = Module.getNamedGlobal(MangledName))
3374 // Serialize the class hierarchy and initialize the CHD Fields.
3375 SmallVector<MSRTTIClass, 8> Classes;
3376 serializeClassHierarchy(Classes, RD);
3377 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3378 detectAmbiguousBases(Classes);
3380 for (auto Class : Classes) {
3381 if (Class.RD->getNumBases() > 1)
3382 Flags |= HasBranchingHierarchy;
3383 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3384 // believe the field isn't actually used.
3385 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3386 Flags |= HasAmbiguousBases;
3388 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3389 Flags |= HasVirtualBranchingHierarchy;
3390 // These gep indices are used to get the address of the first element of the
3391 // base class array.
3392 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3393 llvm::ConstantInt::get(CGM.IntTy, 0)};
3395 // Forward-declare the class hierarchy descriptor
3396 auto Type = ABI.getClassHierarchyDescriptorType();
3397 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3398 /*Initializer=*/nullptr,
3399 StringRef(MangledName));
3400 if (CHD->isWeakForLinker())
3401 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3403 auto *Bases = getBaseClassArray(Classes);
3405 // Initialize the base class ClassHierarchyDescriptor.
3406 llvm::Constant *Fields[] = {
3407 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3408 llvm::ConstantInt::get(CGM.IntTy, Flags),
3409 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3410 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3411 Bases->getValueType(), Bases,
3412 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3414 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3418 llvm::GlobalVariable *
3419 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3420 SmallString<256> MangledName;
3422 llvm::raw_svector_ostream Out(MangledName);
3423 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3426 // Forward-declare the base class array.
3427 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3428 // mode) bytes of padding. We provide a pointer sized amount of padding by
3429 // adding +1 to Classes.size(). The sections have pointer alignment and are
3430 // marked pick-any so it shouldn't matter.
3431 llvm::Type *PtrType = ABI.getImageRelativeType(
3432 ABI.getBaseClassDescriptorType()->getPointerTo());
3433 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3435 new llvm::GlobalVariable(Module, ArrType,
3436 /*Constant=*/true, Linkage,
3437 /*Initializer=*/nullptr, StringRef(MangledName));
3438 if (BCA->isWeakForLinker())
3439 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3441 // Initialize the BaseClassArray.
3442 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3443 for (MSRTTIClass &Class : Classes)
3444 BaseClassArrayData.push_back(
3445 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3446 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3447 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3451 llvm::GlobalVariable *
3452 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3453 // Compute the fields for the BaseClassDescriptor. They are computed up front
3454 // because they are mangled into the name of the object.
3455 uint32_t OffsetInVBTable = 0;
3456 int32_t VBPtrOffset = -1;
3457 if (Class.VirtualRoot) {
3458 auto &VTableContext = CGM.getMicrosoftVTableContext();
3459 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3460 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3463 SmallString<256> MangledName;
3465 llvm::raw_svector_ostream Out(MangledName);
3466 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3467 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3471 // Check to see if we've already declared this object.
3472 if (auto BCD = Module.getNamedGlobal(MangledName))
3475 // Forward-declare the base class descriptor.
3476 auto Type = ABI.getBaseClassDescriptorType();
3478 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3479 /*Initializer=*/nullptr, StringRef(MangledName));
3480 if (BCD->isWeakForLinker())
3481 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3483 // Initialize the BaseClassDescriptor.
3484 llvm::Constant *Fields[] = {
3485 ABI.getImageRelativeConstant(
3486 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3487 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3488 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3489 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3490 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3491 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3492 ABI.getImageRelativeConstant(
3493 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3495 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3499 llvm::GlobalVariable *
3500 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3501 SmallString<256> MangledName;
3503 llvm::raw_svector_ostream Out(MangledName);
3504 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3507 // Check to see if we've already computed this complete object locator.
3508 if (auto COL = Module.getNamedGlobal(MangledName))
3511 // Compute the fields of the complete object locator.
3512 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3513 int VFPtrOffset = 0;
3514 // The offset includes the vtordisp if one exists.
3515 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3516 if (Context.getASTRecordLayout(RD)
3517 .getVBaseOffsetsMap()
3519 ->second.hasVtorDisp())
3520 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3522 // Forward-declare the complete object locator.
3523 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3524 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3525 /*Initializer=*/nullptr, StringRef(MangledName));
3527 // Initialize the CompleteObjectLocator.
3528 llvm::Constant *Fields[] = {
3529 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3530 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3531 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3532 ABI.getImageRelativeConstant(
3533 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3534 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3535 ABI.getImageRelativeConstant(COL),
3537 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3538 if (!ABI.isImageRelative())
3539 FieldsRef = FieldsRef.drop_back();
3540 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3541 if (COL->isWeakForLinker())
3542 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3546 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3547 bool &IsConst, bool &IsVolatile) {
3548 T = Context.getExceptionObjectType(T);
3550 // C++14 [except.handle]p3:
3551 // A handler is a match for an exception object of type E if [...]
3552 // - the handler is of type cv T or const T& where T is a pointer type and
3553 // E is a pointer type that can be converted to T by [...]
3554 // - a qualification conversion
3557 QualType PointeeType = T->getPointeeType();
3558 if (!PointeeType.isNull()) {
3559 IsConst = PointeeType.isConstQualified();
3560 IsVolatile = PointeeType.isVolatileQualified();
3563 // Member pointer types like "const int A::*" are represented by having RTTI
3564 // for "int A::*" and separately storing the const qualifier.
3565 if (const auto *MPTy = T->getAs<MemberPointerType>())
3566 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3569 // Pointer types like "const int * const *" are represented by having RTTI
3570 // for "const int **" and separately storing the const qualifier.
3571 if (T->isPointerType())
3572 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3578 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3579 QualType CatchHandlerType) {
3580 // TypeDescriptors for exceptions never have qualified pointer types,
3581 // qualifiers are stored seperately in order to support qualification
3583 bool IsConst, IsVolatile;
3584 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3586 bool IsReference = CatchHandlerType->isReferenceType();
3596 SmallString<256> MangledName;
3598 llvm::raw_svector_ostream Out(MangledName);
3599 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3602 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3603 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3605 llvm::Constant *Fields[] = {
3606 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3607 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3609 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3610 auto *Var = new llvm::GlobalVariable(
3611 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3612 llvm::GlobalValue::PrivateLinkage,
3613 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3614 StringRef(MangledName));
3615 Var->setUnnamedAddr(true);
3616 Var->setSection("llvm.metadata");
3620 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3621 /// llvm::GlobalVariable * because different type descriptors have different
3622 /// types, and need to be abstracted. They are abstracting by casting the
3623 /// address to an Int8PtrTy.
3624 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3625 SmallString<256> MangledName;
3627 llvm::raw_svector_ostream Out(MangledName);
3628 getMangleContext().mangleCXXRTTI(Type, Out);
3631 // Check to see if we've already declared this TypeDescriptor.
3632 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3633 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3635 // Compute the fields for the TypeDescriptor.
3636 SmallString<256> TypeInfoString;
3638 llvm::raw_svector_ostream Out(TypeInfoString);
3639 getMangleContext().mangleCXXRTTIName(Type, Out);
3642 // Declare and initialize the TypeDescriptor.
3643 llvm::Constant *Fields[] = {
3644 getTypeInfoVTable(CGM), // VFPtr
3645 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3646 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3647 llvm::StructType *TypeDescriptorType =
3648 getTypeDescriptorType(TypeInfoString);
3649 auto *Var = new llvm::GlobalVariable(
3650 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3651 getLinkageForRTTI(Type),
3652 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3653 StringRef(MangledName));
3654 if (Var->isWeakForLinker())
3655 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3656 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3659 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3660 llvm::GlobalVariable *
3661 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3662 const VPtrInfo *Info) {
3663 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3666 static void emitCXXConstructor(CodeGenModule &CGM,
3667 const CXXConstructorDecl *ctor,
3668 StructorType ctorType) {
3669 // There are no constructor variants, always emit the complete destructor.
3670 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3671 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3674 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3675 StructorType dtorType) {
3676 // The complete destructor is equivalent to the base destructor for
3677 // classes with no virtual bases, so try to emit it as an alias.
3678 if (!dtor->getParent()->getNumVBases() &&
3679 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3680 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3681 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3682 if (ProducedAlias) {
3683 if (dtorType == StructorType::Complete)
3685 if (dtor->isVirtual())
3686 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3690 // The base destructor is equivalent to the base destructor of its
3691 // base class if there is exactly one non-virtual base class with a
3692 // non-trivial destructor, there are no fields with a non-trivial
3693 // destructor, and the body of the destructor is trivial.
3694 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3697 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3698 if (Fn->isWeakForLinker())
3699 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3702 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3703 StructorType Type) {
3704 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3705 emitCXXConstructor(CGM, CD, Type);
3708 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3712 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3714 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3716 // Calculate the mangled name.
3717 SmallString<256> ThunkName;
3718 llvm::raw_svector_ostream Out(ThunkName);
3719 getMangleContext().mangleCXXCtor(CD, CT, Out);
3722 // If the thunk has been generated previously, just return it.
3723 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3724 return cast<llvm::Function>(GV);
3726 // Create the llvm::Function.
3727 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3728 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3729 const CXXRecordDecl *RD = CD->getParent();
3730 QualType RecordTy = getContext().getRecordType(RD);
3731 llvm::Function *ThunkFn = llvm::Function::Create(
3732 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3733 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3734 FnInfo.getEffectiveCallingConvention()));
3735 if (ThunkFn->isWeakForLinker())
3736 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
3737 bool IsCopy = CT == Ctor_CopyingClosure;
3740 CodeGenFunction CGF(CGM);
3741 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3743 // Build FunctionArgs.
3744 FunctionArgList FunctionArgs;
3746 // A constructor always starts with a 'this' pointer as its first argument.
3747 buildThisParam(CGF, FunctionArgs);
3749 // Following the 'this' pointer is a reference to the source object that we
3750 // are copying from.
3751 ImplicitParamDecl SrcParam(
3752 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3753 getContext().getLValueReferenceType(RecordTy,
3754 /*SpelledAsLValue=*/true));
3756 FunctionArgs.push_back(&SrcParam);
3758 // Constructors for classes which utilize virtual bases have an additional
3759 // parameter which indicates whether or not it is being delegated to by a more
3760 // derived constructor.
3761 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3762 &getContext().Idents.get("is_most_derived"),
3763 getContext().IntTy);
3764 // Only add the parameter to the list if thie class has virtual bases.
3765 if (RD->getNumVBases() > 0)
3766 FunctionArgs.push_back(&IsMostDerived);
3768 // Start defining the function.
3769 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3770 FunctionArgs, CD->getLocation(), SourceLocation());
3772 llvm::Value *This = getThisValue(CGF);
3774 llvm::Value *SrcVal =
3775 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3780 // Push the this ptr.
3781 Args.add(RValue::get(This), CD->getThisType(getContext()));
3783 // Push the src ptr.
3785 Args.add(RValue::get(SrcVal), SrcParam.getType());
3787 // Add the rest of the default arguments.
3788 std::vector<Stmt *> ArgVec;
3789 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3790 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3791 assert(DefaultArg && "sema forgot to instantiate default args");
3792 ArgVec.push_back(DefaultArg);
3795 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3797 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3798 ConstExprIterator ArgBegin(ArgVec.data()),
3799 ArgEnd(ArgVec.data() + ArgVec.size());
3800 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3802 // Insert any ABI-specific implicit constructor arguments.
3803 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3804 /*ForVirtualBase=*/false,
3805 /*Delegating=*/false, Args);
3807 // Call the destructor with our arguments.
3808 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3809 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3810 Args, CD, Ctor_Complete, ExtraArgs);
3811 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3813 Cleanups.ForceCleanup();
3815 // Emit the ret instruction, remove any temporary instructions created for the
3817 CGF.FinishFunction(SourceLocation());
3822 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3824 int32_t VBPtrOffset,
3826 assert(!T->isReferenceType());
3828 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3829 const CXXConstructorDecl *CD =
3830 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3831 CXXCtorType CT = Ctor_Complete;
3833 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3834 CT = Ctor_CopyingClosure;
3836 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3837 SmallString<256> MangledName;
3839 llvm::raw_svector_ostream Out(MangledName);
3840 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3841 VBPtrOffset, VBIndex, Out);
3843 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3844 return getImageRelativeConstant(GV);
3846 // The TypeDescriptor is used by the runtime to determine if a catch handler
3847 // is appropriate for the exception object.
3848 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3850 // The runtime is responsible for calling the copy constructor if the
3851 // exception is caught by value.
3852 llvm::Constant *CopyCtor;
3854 if (CT == Ctor_CopyingClosure)
3855 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3857 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3859 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3861 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3863 CopyCtor = getImageRelativeConstant(CopyCtor);
3865 bool IsScalar = !RD;
3866 bool HasVirtualBases = false;
3867 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3868 QualType PointeeType = T;
3869 if (T->isPointerType())
3870 PointeeType = T->getPointeeType();
3871 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3872 HasVirtualBases = RD->getNumVBases() > 0;
3873 if (IdentifierInfo *II = RD->getIdentifier())
3874 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3877 // Encode the relevant CatchableType properties into the Flags bitfield.
3878 // FIXME: Figure out how bits 2 or 8 can get set.
3882 if (HasVirtualBases)
3887 llvm::Constant *Fields[] = {
3888 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3889 TD, // TypeDescriptor
3890 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3891 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3892 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3893 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3894 CopyCtor // CopyCtor
3896 llvm::StructType *CTType = getCatchableTypeType();
3897 auto *GV = new llvm::GlobalVariable(
3898 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3899 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3900 GV->setUnnamedAddr(true);
3901 GV->setSection(".xdata");
3902 if (GV->isWeakForLinker())
3903 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3904 return getImageRelativeConstant(GV);
3907 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3908 assert(!T->isReferenceType());
3910 // See if we've already generated a CatchableTypeArray for this type before.
3911 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3915 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3916 // using a SmallSetVector. Duplicates may arise due to virtual bases
3917 // occurring more than once in the hierarchy.
3918 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3920 // C++14 [except.handle]p3:
3921 // A handler is a match for an exception object of type E if [...]
3922 // - the handler is of type cv T or cv T& and T is an unambiguous public
3923 // base class of E, or
3924 // - the handler is of type cv T or const T& where T is a pointer type and
3925 // E is a pointer type that can be converted to T by [...]
3926 // - a standard pointer conversion (4.10) not involving conversions to
3927 // pointers to private or protected or ambiguous classes
3928 const CXXRecordDecl *MostDerivedClass = nullptr;
3929 bool IsPointer = T->isPointerType();
3931 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3933 MostDerivedClass = T->getAsCXXRecordDecl();
3935 // Collect all the unambiguous public bases of the MostDerivedClass.
3936 if (MostDerivedClass) {
3937 const ASTContext &Context = getContext();
3938 const ASTRecordLayout &MostDerivedLayout =
3939 Context.getASTRecordLayout(MostDerivedClass);
3940 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3941 SmallVector<MSRTTIClass, 8> Classes;
3942 serializeClassHierarchy(Classes, MostDerivedClass);
3943 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3944 detectAmbiguousBases(Classes);
3945 for (const MSRTTIClass &Class : Classes) {
3946 // Skip any ambiguous or private bases.
3948 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3950 // Write down how to convert from a derived pointer to a base pointer.
3951 uint32_t OffsetInVBTable = 0;
3952 int32_t VBPtrOffset = -1;
3953 if (Class.VirtualRoot) {
3955 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3956 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3959 // Turn our record back into a pointer if the exception object is a
3961 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3963 RTTITy = Context.getPointerType(RTTITy);
3964 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3965 VBPtrOffset, OffsetInVBTable));
3969 // C++14 [except.handle]p3:
3970 // A handler is a match for an exception object of type E if
3971 // - The handler is of type cv T or cv T& and E and T are the same type
3972 // (ignoring the top-level cv-qualifiers)
3973 CatchableTypes.insert(getCatchableType(T));
3975 // C++14 [except.handle]p3:
3976 // A handler is a match for an exception object of type E if
3977 // - the handler is of type cv T or const T& where T is a pointer type and
3978 // E is a pointer type that can be converted to T by [...]
3979 // - a standard pointer conversion (4.10) not involving conversions to
3980 // pointers to private or protected or ambiguous classes
3982 // C++14 [conv.ptr]p2:
3983 // A prvalue of type "pointer to cv T," where T is an object type, can be
3984 // converted to a prvalue of type "pointer to cv void".
3985 if (IsPointer && T->getPointeeType()->isObjectType())
3986 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3988 // C++14 [except.handle]p3:
3989 // A handler is a match for an exception object of type E if [...]
3990 // - the handler is of type cv T or const T& where T is a pointer or
3991 // pointer to member type and E is std::nullptr_t.
3993 // We cannot possibly list all possible pointer types here, making this
3994 // implementation incompatible with the standard. However, MSVC includes an
3995 // entry for pointer-to-void in this case. Let's do the same.
3996 if (T->isNullPtrType())
3997 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3999 uint32_t NumEntries = CatchableTypes.size();
4000 llvm::Type *CTType =
4001 getImageRelativeType(getCatchableTypeType()->getPointerTo());
4002 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
4003 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
4004 llvm::Constant *Fields[] = {
4005 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
4006 llvm::ConstantArray::get(
4007 AT, llvm::makeArrayRef(CatchableTypes.begin(),
4008 CatchableTypes.end())) // CatchableTypes
4010 SmallString<256> MangledName;
4012 llvm::raw_svector_ostream Out(MangledName);
4013 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
4015 CTA = new llvm::GlobalVariable(
4016 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
4017 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
4018 CTA->setUnnamedAddr(true);
4019 CTA->setSection(".xdata");
4020 if (CTA->isWeakForLinker())
4021 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
4025 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
4026 bool IsConst, IsVolatile;
4027 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
4029 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
4030 // the exception object may be caught as.
4031 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
4032 // The first field in a CatchableTypeArray is the number of CatchableTypes.
4033 // This is used as a component of the mangled name which means that we need to
4034 // know what it is in order to see if we have previously generated the
4036 uint32_t NumEntries =
4037 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
4038 ->getLimitedValue();
4040 SmallString<256> MangledName;
4042 llvm::raw_svector_ostream Out(MangledName);
4043 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
4047 // Reuse a previously generated ThrowInfo if we have generated an appropriate
4049 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
4052 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
4053 // be at least as CV qualified. Encode this requirement into the Flags
4061 // The cleanup-function (a destructor) must be called when the exception
4062 // object's lifetime ends.
4063 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
4064 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4065 if (CXXDestructorDecl *DtorD = RD->getDestructor())
4066 if (!DtorD->isTrivial())
4067 CleanupFn = llvm::ConstantExpr::getBitCast(
4068 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
4070 // This is unused as far as we can tell, initialize it to null.
4071 llvm::Constant *ForwardCompat =
4072 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
4073 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
4074 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
4075 llvm::StructType *TIType = getThrowInfoType();
4076 llvm::Constant *Fields[] = {
4077 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4078 getImageRelativeConstant(CleanupFn), // CleanupFn
4079 ForwardCompat, // ForwardCompat
4080 PointerToCatchableTypes // CatchableTypeArray
4082 auto *GV = new llvm::GlobalVariable(
4083 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
4084 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
4085 GV->setUnnamedAddr(true);
4086 GV->setSection(".xdata");
4087 if (GV->isWeakForLinker())
4088 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4092 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
4093 const Expr *SubExpr = E->getSubExpr();
4094 QualType ThrowType = SubExpr->getType();
4095 // The exception object lives on the stack and it's address is passed to the
4096 // runtime function.
4097 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
4098 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4101 // The so-called ThrowInfo is used to describe how the exception object may be
4103 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4105 // Call into the runtime to throw the exception.
4106 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
4107 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);