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;
109 bool canEmitAvailableExternallyVTable(
110 const CXXRecordDecl *RD) const override {
115 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
116 const CXXRecordDecl *ClassDecl,
117 const CXXRecordDecl *BaseClassDecl) override;
120 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
121 const CXXRecordDecl *RD) override;
123 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
124 const CXXRecordDecl *RD) override;
126 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
128 // Background on MSVC destructors
129 // ==============================
131 // Both Itanium and MSVC ABIs have destructor variants. The variant names
132 // roughly correspond in the following way:
134 // Base -> no name, just ~Class
135 // Complete -> vbase destructor
136 // Deleting -> scalar deleting destructor
137 // vector deleting destructor
139 // The base and complete destructors are the same as in Itanium, although the
140 // complete destructor does not accept a VTT parameter when there are virtual
141 // bases. A separate mechanism involving vtordisps is used to ensure that
142 // virtual methods of destroyed subobjects are not called.
144 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
145 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
146 // pointer points to an array. The scalar deleting destructor assumes that
147 // bit 2 is zero, and therefore does not contain a loop.
149 // For virtual destructors, only one entry is reserved in the vftable, and it
150 // always points to the vector deleting destructor. The vector deleting
151 // destructor is the most general, so it can be used to destroy objects in
152 // place, delete single heap objects, or delete arrays.
154 // A TU defining a non-inline destructor is only guaranteed to emit a base
155 // destructor, and all of the other variants are emitted on an as-needed basis
156 // in COMDATs. Because a non-base destructor can be emitted in a TU that
157 // lacks a definition for the destructor, non-base destructors must always
158 // delegate to or alias the base destructor.
160 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
161 SmallVectorImpl<CanQualType> &ArgTys) override;
163 /// Non-base dtors should be emitted as delegating thunks in this ABI.
164 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
165 CXXDtorType DT) const override {
166 return DT != Dtor_Base;
169 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
171 const CXXRecordDecl *
172 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
173 MD = MD->getCanonicalDecl();
174 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
175 MicrosoftVTableContext::MethodVFTableLocation ML =
176 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
177 // The vbases might be ordered differently in the final overrider object
178 // and the complete object, so the "this" argument may sometimes point to
179 // memory that has no particular type (e.g. past the complete object).
180 // In this case, we just use a generic pointer type.
181 // FIXME: might want to have a more precise type in the non-virtual
182 // multiple inheritance case.
183 if (ML.VBase || !ML.VFPtrOffset.isZero())
186 return MD->getParent();
190 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
192 bool VirtualCall) override;
194 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
195 FunctionArgList &Params) override;
197 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
198 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
200 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
202 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
203 const CXXConstructorDecl *D,
204 CXXCtorType Type, bool ForVirtualBase,
206 CallArgList &Args) override;
208 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
209 CXXDtorType Type, bool ForVirtualBase,
210 bool Delegating, llvm::Value *This) override;
212 void emitVTableBitSetEntries(VPtrInfo *Info, const CXXRecordDecl *RD,
213 llvm::GlobalVariable *VTable);
215 void emitVTableDefinitions(CodeGenVTables &CGVT,
216 const CXXRecordDecl *RD) override;
218 llvm::Value *getVTableAddressPointInStructor(
219 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
220 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
221 bool &NeedsVirtualOffset) override;
224 getVTableAddressPointForConstExpr(BaseSubobject Base,
225 const CXXRecordDecl *VTableClass) override;
227 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
228 CharUnits VPtrOffset) override;
230 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
231 llvm::Value *This, llvm::Type *Ty,
232 SourceLocation Loc) override;
234 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
235 const CXXDestructorDecl *Dtor,
236 CXXDtorType DtorType,
238 const CXXMemberCallExpr *CE) override;
240 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
241 CallArgList &CallArgs) override {
242 assert(GD.getDtorType() == Dtor_Deleting &&
243 "Only deleting destructor thunks are available in this ABI");
244 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
248 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
250 llvm::GlobalVariable *
251 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
252 llvm::GlobalVariable::LinkageTypes Linkage);
254 llvm::GlobalVariable *
255 getAddrOfVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
256 const CXXRecordDecl *DstRD) {
257 SmallString<256> OutName;
258 llvm::raw_svector_ostream Out(OutName);
259 getMangleContext().mangleCXXVirtualDisplacementMap(SrcRD, DstRD, Out);
260 StringRef MangledName = OutName.str();
262 if (auto *VDispMap = CGM.getModule().getNamedGlobal(MangledName))
265 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
266 unsigned NumEntries = 1 + SrcRD->getNumVBases();
267 SmallVector<llvm::Constant *, 4> Map(NumEntries,
268 llvm::UndefValue::get(CGM.IntTy));
269 Map[0] = llvm::ConstantInt::get(CGM.IntTy, 0);
270 bool AnyDifferent = false;
271 for (const auto &I : SrcRD->vbases()) {
272 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
273 if (!DstRD->isVirtuallyDerivedFrom(VBase))
276 unsigned SrcVBIndex = VTContext.getVBTableIndex(SrcRD, VBase);
277 unsigned DstVBIndex = VTContext.getVBTableIndex(DstRD, VBase);
278 Map[SrcVBIndex] = llvm::ConstantInt::get(CGM.IntTy, DstVBIndex * 4);
279 AnyDifferent |= SrcVBIndex != DstVBIndex;
281 // This map would be useless, don't use it.
285 llvm::ArrayType *VDispMapTy = llvm::ArrayType::get(CGM.IntTy, Map.size());
286 llvm::Constant *Init = llvm::ConstantArray::get(VDispMapTy, Map);
287 llvm::GlobalValue::LinkageTypes Linkage =
288 SrcRD->isExternallyVisible() && DstRD->isExternallyVisible()
289 ? llvm::GlobalValue::LinkOnceODRLinkage
290 : llvm::GlobalValue::InternalLinkage;
291 auto *VDispMap = new llvm::GlobalVariable(
292 CGM.getModule(), VDispMapTy, /*Constant=*/true, Linkage,
293 /*Initializer=*/Init, MangledName);
297 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
298 llvm::GlobalVariable *GV) const;
300 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
301 GlobalDecl GD, bool ReturnAdjustment) override {
302 // Never dllimport/dllexport thunks.
303 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
306 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
308 if (Linkage == GVA_Internal)
309 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
310 else if (ReturnAdjustment)
311 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
313 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
316 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
317 const ThisAdjustment &TA) override;
319 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
320 const ReturnAdjustment &RA) override;
322 void EmitThreadLocalInitFuncs(
324 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
326 ArrayRef<llvm::Function *> CXXThreadLocalInits,
327 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
329 bool usesThreadWrapperFunction() const override { return false; }
330 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
331 QualType LValType) override;
333 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
334 llvm::GlobalVariable *DeclPtr,
335 bool PerformInit) override;
336 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
337 llvm::Constant *Dtor, llvm::Constant *Addr) override;
339 // ==== Notes on array cookies =========
341 // MSVC seems to only use cookies when the class has a destructor; a
342 // two-argument usual array deallocation function isn't sufficient.
344 // For example, this code prints "100" and "1":
347 // void *operator new[](size_t sz) {
348 // printf("%u\n", sz);
349 // return malloc(sz);
351 // void operator delete[](void *p, size_t sz) {
352 // printf("%u\n", sz);
357 // A *p = new A[100];
360 // Whereas it prints "104" and "104" if you give A a destructor.
362 bool requiresArrayCookie(const CXXDeleteExpr *expr,
363 QualType elementType) override;
364 bool requiresArrayCookie(const CXXNewExpr *expr) override;
365 CharUnits getArrayCookieSizeImpl(QualType type) override;
366 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
368 llvm::Value *NumElements,
369 const CXXNewExpr *expr,
370 QualType ElementType) override;
371 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
372 llvm::Value *allocPtr,
373 CharUnits cookieSize) override;
375 friend struct MSRTTIBuilder;
377 bool isImageRelative() const {
378 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
381 // 5 routines for constructing the llvm types for MS RTTI structs.
382 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
383 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
384 TDTypeName += llvm::utostr(TypeInfoString.size());
385 llvm::StructType *&TypeDescriptorType =
386 TypeDescriptorTypeMap[TypeInfoString.size()];
387 if (TypeDescriptorType)
388 return TypeDescriptorType;
389 llvm::Type *FieldTypes[] = {
392 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
394 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
395 return TypeDescriptorType;
398 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
399 if (!isImageRelative())
404 llvm::StructType *getBaseClassDescriptorType() {
405 if (BaseClassDescriptorType)
406 return BaseClassDescriptorType;
407 llvm::Type *FieldTypes[] = {
408 getImageRelativeType(CGM.Int8PtrTy),
414 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
416 BaseClassDescriptorType = llvm::StructType::create(
417 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
418 return BaseClassDescriptorType;
421 llvm::StructType *getClassHierarchyDescriptorType() {
422 if (ClassHierarchyDescriptorType)
423 return ClassHierarchyDescriptorType;
424 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
425 ClassHierarchyDescriptorType = llvm::StructType::create(
426 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
427 llvm::Type *FieldTypes[] = {
431 getImageRelativeType(
432 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
434 ClassHierarchyDescriptorType->setBody(FieldTypes);
435 return ClassHierarchyDescriptorType;
438 llvm::StructType *getCompleteObjectLocatorType() {
439 if (CompleteObjectLocatorType)
440 return CompleteObjectLocatorType;
441 CompleteObjectLocatorType = llvm::StructType::create(
442 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
443 llvm::Type *FieldTypes[] = {
447 getImageRelativeType(CGM.Int8PtrTy),
448 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
449 getImageRelativeType(CompleteObjectLocatorType),
451 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
452 if (!isImageRelative())
453 FieldTypesRef = FieldTypesRef.drop_back();
454 CompleteObjectLocatorType->setBody(FieldTypesRef);
455 return CompleteObjectLocatorType;
458 llvm::GlobalVariable *getImageBase() {
459 StringRef Name = "__ImageBase";
460 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
463 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
465 llvm::GlobalValue::ExternalLinkage,
466 /*Initializer=*/nullptr, Name);
469 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
470 if (!isImageRelative())
473 if (PtrVal->isNullValue())
474 return llvm::Constant::getNullValue(CGM.IntTy);
476 llvm::Constant *ImageBaseAsInt =
477 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
478 llvm::Constant *PtrValAsInt =
479 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
480 llvm::Constant *Diff =
481 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
482 /*HasNUW=*/true, /*HasNSW=*/true);
483 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
487 MicrosoftMangleContext &getMangleContext() {
488 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
491 llvm::Constant *getZeroInt() {
492 return llvm::ConstantInt::get(CGM.IntTy, 0);
495 llvm::Constant *getAllOnesInt() {
496 return llvm::Constant::getAllOnesValue(CGM.IntTy);
499 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
500 return C ? C : getZeroInt();
503 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
504 return C ? C : getZeroInt();
507 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
510 GetNullMemberPointerFields(const MemberPointerType *MPT,
511 llvm::SmallVectorImpl<llvm::Constant *> &fields);
513 /// \brief Shared code for virtual base adjustment. Returns the offset from
514 /// the vbptr to the virtual base. Optionally returns the address of the
516 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
518 llvm::Value *VBPtrOffset,
519 llvm::Value *VBTableOffset,
520 llvm::Value **VBPtr = nullptr);
522 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
525 int32_t VBTableOffset,
526 llvm::Value **VBPtr = nullptr) {
527 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
528 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
529 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
530 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
533 std::pair<llvm::Value *, llvm::Value *>
534 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
535 QualType SrcRecordTy);
537 /// \brief Performs a full virtual base adjustment. Used to dereference
538 /// pointers to members of virtual bases.
539 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
540 const CXXRecordDecl *RD, llvm::Value *Base,
541 llvm::Value *VirtualBaseAdjustmentOffset,
542 llvm::Value *VBPtrOffset /* optional */);
544 /// \brief Emits a full member pointer with the fields common to data and
545 /// function member pointers.
546 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
547 bool IsMemberFunction,
548 const CXXRecordDecl *RD,
549 CharUnits NonVirtualBaseAdjustment,
550 unsigned VBTableIndex);
552 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
555 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
556 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
558 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
559 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
561 /// \brief Generate a thunk for calling a virtual member function MD.
562 llvm::Function *EmitVirtualMemPtrThunk(
563 const CXXMethodDecl *MD,
564 const MicrosoftVTableContext::MethodVFTableLocation &ML);
567 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
569 bool isZeroInitializable(const MemberPointerType *MPT) override;
571 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
572 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
573 return RD->hasAttr<MSInheritanceAttr>();
576 bool isTypeInfoCalculable(QualType Ty) const override {
577 if (!CGCXXABI::isTypeInfoCalculable(Ty))
579 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
580 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
581 if (!RD->hasAttr<MSInheritanceAttr>())
587 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
589 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
590 CharUnits offset) override;
591 llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override;
592 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
594 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
597 const MemberPointerType *MPT,
598 bool Inequality) override;
600 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
602 const MemberPointerType *MPT) override;
605 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
606 llvm::Value *Base, llvm::Value *MemPtr,
607 const MemberPointerType *MPT) override;
609 llvm::Value *EmitNonNullMemberPointerConversion(
610 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
611 CastKind CK, CastExpr::path_const_iterator PathBegin,
612 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
613 CGBuilderTy &Builder);
615 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
617 llvm::Value *Src) override;
619 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
620 llvm::Constant *Src) override;
622 llvm::Constant *EmitMemberPointerConversion(
623 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
624 CastKind CK, CastExpr::path_const_iterator PathBegin,
625 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
628 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
629 llvm::Value *&This, llvm::Value *MemPtr,
630 const MemberPointerType *MPT) override;
632 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
634 llvm::StructType *getCatchHandlerTypeType() {
635 if (!CatchHandlerTypeType) {
636 llvm::Type *FieldTypes[] = {
638 CGM.Int8PtrTy, // TypeDescriptor
640 CatchHandlerTypeType = llvm::StructType::create(
641 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
643 return CatchHandlerTypeType;
646 llvm::StructType *getCatchableTypeType() {
647 if (CatchableTypeType)
648 return CatchableTypeType;
649 llvm::Type *FieldTypes[] = {
651 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
652 CGM.IntTy, // NonVirtualAdjustment
653 CGM.IntTy, // OffsetToVBPtr
654 CGM.IntTy, // VBTableIndex
656 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
658 CatchableTypeType = llvm::StructType::create(
659 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
660 return CatchableTypeType;
663 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
664 llvm::StructType *&CatchableTypeArrayType =
665 CatchableTypeArrayTypeMap[NumEntries];
666 if (CatchableTypeArrayType)
667 return CatchableTypeArrayType;
669 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
670 CTATypeName += llvm::utostr(NumEntries);
672 getImageRelativeType(getCatchableTypeType()->getPointerTo());
673 llvm::Type *FieldTypes[] = {
674 CGM.IntTy, // NumEntries
675 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
677 CatchableTypeArrayType =
678 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
679 return CatchableTypeArrayType;
682 llvm::StructType *getThrowInfoType() {
684 return ThrowInfoType;
685 llvm::Type *FieldTypes[] = {
687 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
688 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
689 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
691 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
693 return ThrowInfoType;
696 llvm::Constant *getThrowFn() {
697 // _CxxThrowException is passed an exception object and a ThrowInfo object
698 // which describes the exception.
699 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
700 llvm::FunctionType *FTy =
701 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
702 auto *Fn = cast<llvm::Function>(
703 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
704 // _CxxThrowException is stdcall on 32-bit x86 platforms.
705 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
706 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
710 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
713 llvm::Constant *getCatchableType(QualType T,
714 uint32_t NVOffset = 0,
715 int32_t VBPtrOffset = -1,
716 uint32_t VBIndex = 0);
718 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
720 llvm::GlobalVariable *getThrowInfo(QualType T) override;
723 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
724 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
725 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
726 /// \brief All the vftables that have been referenced.
727 VFTablesMapTy VFTablesMap;
728 VTablesMapTy VTablesMap;
730 /// \brief This set holds the record decls we've deferred vtable emission for.
731 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
734 /// \brief All the vbtables which have been referenced.
735 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
737 /// Info on the global variable used to guard initialization of static locals.
738 /// The BitIndex field is only used for externally invisible declarations.
740 GuardInfo() : Guard(nullptr), BitIndex(0) {}
741 llvm::GlobalVariable *Guard;
745 /// Map from DeclContext to the current guard variable. We assume that the
746 /// AST is visited in source code order.
747 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
748 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
749 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
751 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
752 llvm::StructType *BaseClassDescriptorType;
753 llvm::StructType *ClassHierarchyDescriptorType;
754 llvm::StructType *CompleteObjectLocatorType;
756 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
758 llvm::StructType *CatchableTypeType;
759 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
760 llvm::StructType *ThrowInfoType;
761 llvm::StructType *CatchHandlerTypeType;
766 CGCXXABI::RecordArgABI
767 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
768 switch (CGM.getTarget().getTriple().getArch()) {
770 // FIXME: Implement for other architectures.
773 case llvm::Triple::x86:
774 // All record arguments are passed in memory on x86. Decide whether to
775 // construct the object directly in argument memory, or to construct the
776 // argument elsewhere and copy the bytes during the call.
778 // If C++ prohibits us from making a copy, construct the arguments directly
779 // into argument memory.
780 if (!canCopyArgument(RD))
781 return RAA_DirectInMemory;
783 // Otherwise, construct the argument into a temporary and copy the bytes
784 // into the outgoing argument memory.
787 case llvm::Triple::x86_64:
788 // Win64 passes objects with non-trivial copy ctors indirectly.
789 if (RD->hasNonTrivialCopyConstructor())
792 // If an object has a destructor, we'd really like to pass it indirectly
793 // because it allows us to elide copies. Unfortunately, MSVC makes that
794 // impossible for small types, which it will pass in a single register or
795 // stack slot. Most objects with dtors are large-ish, so handle that early.
796 // We can't call out all large objects as being indirect because there are
797 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
798 // how we pass large POD types.
799 if (RD->hasNonTrivialDestructor() &&
800 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
803 // We have a trivial copy constructor or no copy constructors, but we have
804 // to make sure it isn't deleted.
805 bool CopyDeleted = false;
806 for (const CXXConstructorDecl *CD : RD->ctors()) {
807 if (CD->isCopyConstructor()) {
808 assert(CD->isTrivial());
809 // We had at least one undeleted trivial copy ctor. Return directly.
810 if (!CD->isDeleted())
816 // The trivial copy constructor was deleted. Return indirectly.
820 // There were no copy ctors. Return in RAX.
824 llvm_unreachable("invalid enum");
827 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
828 const CXXDeleteExpr *DE,
830 QualType ElementType,
831 const CXXDestructorDecl *Dtor) {
832 // FIXME: Provide a source location here even though there's no
833 // CXXMemberCallExpr for dtor call.
834 bool UseGlobalDelete = DE->isGlobalDelete();
835 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
836 llvm::Value *MDThis =
837 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
839 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
842 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
843 llvm::Value *Args[] = {
844 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
845 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
846 auto *Fn = getThrowFn();
848 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
850 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
854 struct CallEndCatchMSVC final : EHScopeStack::Cleanup {
855 llvm::CatchPadInst *CPI;
857 CallEndCatchMSVC(llvm::CatchPadInst *CPI) : CPI(CPI) {}
859 void Emit(CodeGenFunction &CGF, Flags flags) override {
860 if (CGF.CGM.getCodeGenOpts().NewMSEH) {
861 llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
862 CGF.Builder.CreateCatchRet(BB, CPI);
865 CGF.EmitNounwindRuntimeCall(
866 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
872 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
873 const CXXCatchStmt *S) {
874 // In the MS ABI, the runtime handles the copy, and the catch handler is
875 // responsible for destruction.
876 VarDecl *CatchParam = S->getExceptionDecl();
877 llvm::Value *Exn = nullptr;
878 llvm::Function *BeginCatch = nullptr;
879 llvm::CatchPadInst *CPI = nullptr;
880 bool NewEH = CGF.CGM.getCodeGenOpts().NewMSEH;
882 Exn = CGF.getExceptionFromSlot();
883 BeginCatch = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
885 llvm::BasicBlock *CatchPadBB =
886 CGF.Builder.GetInsertBlock()->getSinglePredecessor();
887 CPI = cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
889 // If this is a catch-all or the catch parameter is unnamed, we don't need to
890 // emit an alloca to the object.
891 if (!CatchParam || !CatchParam->getDeclName()) {
893 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
894 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
896 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup, CPI);
900 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
902 llvm::Value *ParamAddr =
903 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
904 llvm::Value *Args[2] = {Exn, ParamAddr};
905 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
907 CPI->setArgOperand(1, var.getObjectAddress(CGF));
909 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup, CPI);
910 CGF.EmitAutoVarCleanups(var);
913 std::pair<llvm::Value *, llvm::Value *>
914 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
915 QualType SrcRecordTy) {
916 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
917 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
918 const ASTContext &Context = getContext();
920 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
921 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
923 // Perform a base adjustment.
924 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
925 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
926 [&](const CXXBaseSpecifier &Base) {
927 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
928 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
930 llvm::Value *Offset = GetVirtualBaseClassOffset(
931 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
932 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
933 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
934 return std::make_pair(Value, Offset);
937 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
938 QualType SrcRecordTy) {
939 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
941 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
944 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
945 llvm::Value *Argument) {
946 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
947 llvm::FunctionType *FTy =
948 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
949 llvm::Value *Args[] = {Argument};
950 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
951 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
954 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
955 llvm::CallSite Call =
956 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
957 Call.setDoesNotReturn();
958 CGF.Builder.CreateUnreachable();
961 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
962 QualType SrcRecordTy,
963 llvm::Value *ThisPtr,
964 llvm::Type *StdTypeInfoPtrTy) {
966 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
967 return CGF.Builder.CreateBitCast(
968 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
971 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
972 QualType SrcRecordTy) {
973 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
975 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
978 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
979 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
980 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
981 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
983 llvm::Value *SrcRTTI =
984 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
985 llvm::Value *DestRTTI =
986 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
989 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
991 // PVOID __RTDynamicCast(
997 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
998 CGF.Int8PtrTy, CGF.Int32Ty};
999 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
1000 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
1002 llvm::Value *Args[] = {
1003 Value, Offset, SrcRTTI, DestRTTI,
1004 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
1005 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
1006 return CGF.Builder.CreateBitCast(Value, DestLTy);
1010 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
1011 QualType SrcRecordTy,
1013 llvm::Value *Offset;
1014 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
1016 // PVOID __RTCastToVoid(
1018 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
1019 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
1020 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
1022 llvm::Value *Args[] = {Value};
1023 return CGF.EmitRuntimeCall(Function, Args);
1026 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
1030 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
1031 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
1032 const CXXRecordDecl *BaseClassDecl) {
1033 const ASTContext &Context = getContext();
1034 int64_t VBPtrChars =
1035 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
1036 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
1037 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
1038 CharUnits VBTableChars =
1040 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
1041 llvm::Value *VBTableOffset =
1042 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
1044 llvm::Value *VBPtrToNewBase =
1045 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
1047 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
1048 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
1051 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
1052 return isa<CXXConstructorDecl>(GD.getDecl());
1055 static bool isDeletingDtor(GlobalDecl GD) {
1056 return isa<CXXDestructorDecl>(GD.getDecl()) &&
1057 GD.getDtorType() == Dtor_Deleting;
1060 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
1061 return isDeletingDtor(GD);
1064 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
1065 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
1069 if (FI.isInstanceMethod()) {
1070 // If it's an instance method, aggregates are always returned indirectly via
1071 // the second parameter.
1072 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1073 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
1075 } else if (!RD->isPOD()) {
1076 // If it's a free function, non-POD types are returned indirectly.
1077 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1081 // Otherwise, use the C ABI rules.
1086 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1087 const CXXRecordDecl *RD) {
1088 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1089 assert(IsMostDerivedClass &&
1090 "ctor for a class with virtual bases must have an implicit parameter");
1091 llvm::Value *IsCompleteObject =
1092 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1094 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1095 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1096 CGF.Builder.CreateCondBr(IsCompleteObject,
1097 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1099 CGF.EmitBlock(CallVbaseCtorsBB);
1101 // Fill in the vbtable pointers here.
1102 EmitVBPtrStores(CGF, RD);
1104 // CGF will put the base ctor calls in this basic block for us later.
1106 return SkipVbaseCtorsBB;
1109 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1110 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1111 // In most cases, an override for a vbase virtual method can adjust
1112 // the "this" parameter by applying a constant offset.
1113 // However, this is not enough while a constructor or a destructor of some
1114 // class X is being executed if all the following conditions are met:
1115 // - X has virtual bases, (1)
1116 // - X overrides a virtual method M of a vbase Y, (2)
1117 // - X itself is a vbase of the most derived class.
1119 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1120 // which holds the extra amount of "this" adjustment we must do when we use
1121 // the X vftables (i.e. during X ctor or dtor).
1122 // Outside the ctors and dtors, the values of vtorDisps are zero.
1124 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1125 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1126 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1127 CGBuilderTy &Builder = CGF.Builder;
1130 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1131 llvm::Value *Int8This = nullptr; // Initialize lazily.
1133 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1135 if (!I->second.hasVtorDisp())
1138 llvm::Value *VBaseOffset =
1139 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1140 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1141 // just to Trunc back immediately.
1142 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1143 uint64_t ConstantVBaseOffset =
1144 Layout.getVBaseClassOffset(I->first).getQuantity();
1146 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1147 llvm::Value *VtorDispValue = Builder.CreateSub(
1148 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1152 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1153 CGF.Int8Ty->getPointerTo(AS));
1154 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1155 // vtorDisp is always the 32-bits before the vbase in the class layout.
1156 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1157 VtorDispPtr = Builder.CreateBitCast(
1158 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1160 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1164 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1165 const CXXMethodDecl *MD) {
1166 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1167 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1168 CallingConv ActualCallingConv =
1169 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1170 return ExpectedCallingConv == ActualCallingConv;
1173 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1174 // There's only one constructor type in this ABI.
1175 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1177 // Exported default constructors either have a simple call-site where they use
1178 // the typical calling convention and have a single 'this' pointer for an
1179 // argument -or- they get a wrapper function which appropriately thunks to the
1180 // real default constructor. This thunk is the default constructor closure.
1181 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1182 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1183 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1184 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1185 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1189 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1190 const CXXRecordDecl *RD) {
1191 llvm::Value *ThisInt8Ptr =
1192 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1193 const ASTContext &Context = getContext();
1194 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1196 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1197 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1198 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1199 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1200 const ASTRecordLayout &SubobjectLayout =
1201 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1202 CharUnits Offs = VBT->NonVirtualOffset;
1203 Offs += SubobjectLayout.getVBPtrOffset();
1204 if (VBT->getVBaseWithVPtr())
1205 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1206 llvm::Value *VBPtr =
1207 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1208 llvm::Value *GVPtr =
1209 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1210 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1211 "vbptr." + VBT->ReusingBase->getName());
1212 CGF.Builder.CreateStore(GVPtr, VBPtr);
1217 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1218 SmallVectorImpl<CanQualType> &ArgTys) {
1219 // TODO: 'for base' flag
1220 if (T == StructorType::Deleting) {
1221 // The scalar deleting destructor takes an implicit int parameter.
1222 ArgTys.push_back(getContext().IntTy);
1224 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1228 // All parameters are already in place except is_most_derived, which goes
1229 // after 'this' if it's variadic and last if it's not.
1231 const CXXRecordDecl *Class = CD->getParent();
1232 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1233 if (Class->getNumVBases()) {
1234 if (FPT->isVariadic())
1235 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1237 ArgTys.push_back(getContext().IntTy);
1241 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1242 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1243 // other destructor variants are delegating thunks.
1244 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1248 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1249 GD = GD.getCanonicalDecl();
1250 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1252 GlobalDecl LookupGD = GD;
1253 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1254 // Complete destructors take a pointer to the complete object as a
1255 // parameter, thus don't need this adjustment.
1256 if (GD.getDtorType() == Dtor_Complete)
1259 // There's no Dtor_Base in vftable but it shares the this adjustment with
1260 // the deleting one, so look it up instead.
1261 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1264 MicrosoftVTableContext::MethodVFTableLocation ML =
1265 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1266 CharUnits Adjustment = ML.VFPtrOffset;
1268 // Normal virtual instance methods need to adjust from the vfptr that first
1269 // defined the virtual method to the virtual base subobject, but destructors
1270 // do not. The vector deleting destructor thunk applies this adjustment for
1272 if (isa<CXXDestructorDecl>(MD))
1273 Adjustment = CharUnits::Zero();
1276 const ASTRecordLayout &DerivedLayout =
1277 getContext().getASTRecordLayout(MD->getParent());
1278 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1284 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1285 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1287 // If the call of a virtual function is not virtual, we just have to
1288 // compensate for the adjustment the virtual function does in its prologue.
1289 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1290 if (Adjustment.isZero())
1293 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1294 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1295 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1296 assert(Adjustment.isPositive());
1297 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1300 GD = GD.getCanonicalDecl();
1301 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1303 GlobalDecl LookupGD = GD;
1304 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1305 // Complete dtors take a pointer to the complete object,
1306 // thus don't need adjustment.
1307 if (GD.getDtorType() == Dtor_Complete)
1310 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1311 // with the base one, so look up the deleting one instead.
1312 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1314 MicrosoftVTableContext::MethodVFTableLocation ML =
1315 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1317 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1318 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1319 CharUnits StaticOffset = ML.VFPtrOffset;
1321 // Base destructors expect 'this' to point to the beginning of the base
1322 // subobject, not the first vfptr that happens to contain the virtual dtor.
1323 // However, we still need to apply the virtual base adjustment.
1324 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1325 StaticOffset = CharUnits::Zero();
1328 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1329 llvm::Value *VBaseOffset =
1330 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1331 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1333 if (!StaticOffset.isZero()) {
1334 assert(StaticOffset.isPositive());
1335 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1337 // Non-virtual adjustment might result in a pointer outside the allocated
1338 // object, e.g. if the final overrider class is laid out after the virtual
1339 // base that declares a method in the most derived class.
1340 // FIXME: Update the code that emits this adjustment in thunks prologues.
1341 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1343 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1344 StaticOffset.getQuantity());
1350 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1352 FunctionArgList &Params) {
1353 ASTContext &Context = getContext();
1354 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1355 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1356 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1357 ImplicitParamDecl *IsMostDerived
1358 = ImplicitParamDecl::Create(Context, nullptr,
1359 CGF.CurGD.getDecl()->getLocation(),
1360 &Context.Idents.get("is_most_derived"),
1362 // The 'most_derived' parameter goes second if the ctor is variadic and last
1363 // if it's not. Dtors can't be variadic.
1364 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1365 if (FPT->isVariadic())
1366 Params.insert(Params.begin() + 1, IsMostDerived);
1368 Params.push_back(IsMostDerived);
1369 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1370 } else if (isDeletingDtor(CGF.CurGD)) {
1371 ImplicitParamDecl *ShouldDelete
1372 = ImplicitParamDecl::Create(Context, nullptr,
1373 CGF.CurGD.getDecl()->getLocation(),
1374 &Context.Idents.get("should_call_delete"),
1376 Params.push_back(ShouldDelete);
1377 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1381 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1382 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1383 // In this ABI, every virtual function takes a pointer to one of the
1384 // subobjects that first defines it as the 'this' parameter, rather than a
1385 // pointer to the final overrider subobject. Thus, we need to adjust it back
1386 // to the final overrider subobject before use.
1387 // See comments in the MicrosoftVFTableContext implementation for the details.
1388 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1389 if (Adjustment.isZero())
1392 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1393 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1394 *thisTy = This->getType();
1396 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1397 assert(Adjustment.isPositive());
1398 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1399 -Adjustment.getQuantity());
1400 return CGF.Builder.CreateBitCast(This, thisTy);
1403 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1406 /// If this is a function that the ABI specifies returns 'this', initialize
1407 /// the return slot to 'this' at the start of the function.
1409 /// Unlike the setting of return types, this is done within the ABI
1410 /// implementation instead of by clients of CGCXXABI because:
1411 /// 1) getThisValue is currently protected
1412 /// 2) in theory, an ABI could implement 'this' returns some other way;
1413 /// HasThisReturn only specifies a contract, not the implementation
1414 if (HasThisReturn(CGF.CurGD))
1415 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1416 else if (hasMostDerivedReturn(CGF.CurGD))
1417 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1420 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1421 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1422 assert(getStructorImplicitParamDecl(CGF) &&
1423 "no implicit parameter for a constructor with virtual bases?");
1424 getStructorImplicitParamValue(CGF)
1425 = CGF.Builder.CreateLoad(
1426 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1430 if (isDeletingDtor(CGF.CurGD)) {
1431 assert(getStructorImplicitParamDecl(CGF) &&
1432 "no implicit parameter for a deleting destructor?");
1433 getStructorImplicitParamValue(CGF)
1434 = CGF.Builder.CreateLoad(
1435 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1436 "should_call_delete");
1440 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1441 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1442 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1443 assert(Type == Ctor_Complete || Type == Ctor_Base);
1445 // Check if we need a 'most_derived' parameter.
1446 if (!D->getParent()->getNumVBases())
1449 // Add the 'most_derived' argument second if we are variadic or last if not.
1450 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1451 llvm::Value *MostDerivedArg =
1452 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1453 RValue RV = RValue::get(MostDerivedArg);
1454 if (MostDerivedArg) {
1455 if (FPT->isVariadic())
1456 Args.insert(Args.begin() + 1,
1457 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1459 Args.add(RV, getContext().IntTy);
1462 return 1; // Added one arg.
1465 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1466 const CXXDestructorDecl *DD,
1467 CXXDtorType Type, bool ForVirtualBase,
1468 bool Delegating, llvm::Value *This) {
1469 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1471 if (DD->isVirtual()) {
1472 assert(Type != CXXDtorType::Dtor_Deleting &&
1473 "The deleting destructor should only be called via a virtual call");
1474 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1478 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1479 /*ImplicitParam=*/nullptr,
1480 /*ImplicitParamTy=*/QualType(), nullptr,
1481 getFromDtorType(Type));
1484 void MicrosoftCXXABI::emitVTableBitSetEntries(VPtrInfo *Info,
1485 const CXXRecordDecl *RD,
1486 llvm::GlobalVariable *VTable) {
1487 if (!getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIVCall) &&
1488 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFINVCall) &&
1489 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIDerivedCast) &&
1490 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIUnrelatedCast))
1493 llvm::NamedMDNode *BitsetsMD =
1494 CGM.getModule().getOrInsertNamedMetadata("llvm.bitsets");
1496 // The location of the first virtual function pointer in the virtual table,
1497 // aka the "address point" on Itanium. This is at offset 0 if RTTI is
1498 // disabled, or sizeof(void*) if RTTI is enabled.
1499 CharUnits AddressPoint =
1500 getContext().getLangOpts().RTTIData
1501 ? getContext().toCharUnitsFromBits(
1502 getContext().getTargetInfo().getPointerWidth(0))
1503 : CharUnits::Zero();
1505 if (Info->PathToBaseWithVPtr.empty()) {
1506 if (!CGM.IsCFIBlacklistedRecord(RD))
1507 BitsetsMD->addOperand(
1508 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1512 // Add a bitset entry for the least derived base belonging to this vftable.
1513 if (!CGM.IsCFIBlacklistedRecord(Info->PathToBaseWithVPtr.back()))
1514 BitsetsMD->addOperand(CGM.CreateVTableBitSetEntry(
1515 VTable, AddressPoint, Info->PathToBaseWithVPtr.back()));
1517 // Add a bitset entry for each derived class that is laid out at the same
1518 // offset as the least derived base.
1519 for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) {
1520 const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1];
1521 const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I];
1523 const ASTRecordLayout &Layout =
1524 getContext().getASTRecordLayout(DerivedRD);
1526 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1527 if (VBI == Layout.getVBaseOffsetsMap().end())
1528 Offset = Layout.getBaseClassOffset(BaseRD);
1530 Offset = VBI->second.VBaseOffset;
1531 if (!Offset.isZero())
1533 if (!CGM.IsCFIBlacklistedRecord(DerivedRD))
1534 BitsetsMD->addOperand(
1535 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, DerivedRD));
1538 // Finally do the same for the most derived class.
1539 if (Info->FullOffsetInMDC.isZero() && !CGM.IsCFIBlacklistedRecord(RD))
1540 BitsetsMD->addOperand(
1541 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1544 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1545 const CXXRecordDecl *RD) {
1546 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1547 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1549 for (VPtrInfo *Info : VFPtrs) {
1550 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1551 if (VTable->hasInitializer())
1554 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1555 ? getMSCompleteObjectLocator(RD, Info)
1558 const VTableLayout &VTLayout =
1559 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1560 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1561 RD, VTLayout.vtable_component_begin(),
1562 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1563 VTLayout.getNumVTableThunks(), RTTI);
1565 VTable->setInitializer(Init);
1567 emitVTableBitSetEntries(Info, RD, VTable);
1571 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1572 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1573 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1574 NeedsVirtualOffset = (NearestVBase != nullptr);
1576 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1577 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1578 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1579 if (!VTableAddressPoint) {
1580 assert(Base.getBase()->getNumVBases() &&
1581 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1583 return VTableAddressPoint;
1586 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1587 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1588 SmallString<256> &Name) {
1589 llvm::raw_svector_ostream Out(Name);
1590 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1593 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1594 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1595 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1596 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1597 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1598 assert(VFTable && "Couldn't find a vftable for the given base?");
1602 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1603 CharUnits VPtrOffset) {
1604 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1605 // shouldn't be used in the given record type. We want to cache this result in
1606 // VFTablesMap, thus a simple zero check is not sufficient.
1607 VFTableIdTy ID(RD, VPtrOffset);
1608 VTablesMapTy::iterator I;
1610 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1614 llvm::GlobalVariable *&VTable = I->second;
1616 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1617 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1619 if (DeferredVFTables.insert(RD).second) {
1620 // We haven't processed this record type before.
1621 // Queue up this v-table for possible deferred emission.
1622 CGM.addDeferredVTable(RD);
1625 // Create all the vftables at once in order to make sure each vftable has
1626 // a unique mangled name.
1627 llvm::StringSet<> ObservedMangledNames;
1628 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1629 SmallString<256> Name;
1630 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1631 if (!ObservedMangledNames.insert(Name.str()).second)
1632 llvm_unreachable("Already saw this mangling before?");
1637 VPtrInfo *const *VFPtrI =
1638 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1639 return VPI->FullOffsetInMDC == VPtrOffset;
1641 if (VFPtrI == VFPtrs.end()) {
1642 VFTablesMap[ID] = nullptr;
1645 VPtrInfo *VFPtr = *VFPtrI;
1647 SmallString<256> VFTableName;
1648 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1650 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1651 bool VFTableComesFromAnotherTU =
1652 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1653 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1654 bool VTableAliasIsRequred =
1655 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1657 if (llvm::GlobalValue *VFTable =
1658 CGM.getModule().getNamedGlobal(VFTableName)) {
1659 VFTablesMap[ID] = VFTable;
1660 return VTableAliasIsRequred
1661 ? cast<llvm::GlobalVariable>(
1662 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1663 : cast<llvm::GlobalVariable>(VFTable);
1666 uint64_t NumVTableSlots =
1667 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1668 .getNumVTableComponents();
1669 llvm::GlobalValue::LinkageTypes VTableLinkage =
1670 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1672 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1674 llvm::ArrayType *VTableType =
1675 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1677 // Create a backing variable for the contents of VTable. The VTable may
1678 // or may not include space for a pointer to RTTI data.
1679 llvm::GlobalValue *VFTable;
1680 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1681 /*isConstant=*/true, VTableLinkage,
1682 /*Initializer=*/nullptr, VTableName);
1683 VTable->setUnnamedAddr(true);
1685 llvm::Comdat *C = nullptr;
1686 if (!VFTableComesFromAnotherTU &&
1687 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1688 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1689 VTableAliasIsRequred)))
1690 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1692 // Only insert a pointer into the VFTable for RTTI data if we are not
1693 // importing it. We never reference the RTTI data directly so there is no
1694 // need to make room for it.
1695 if (VTableAliasIsRequred) {
1696 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1697 llvm::ConstantInt::get(CGM.IntTy, 1)};
1698 // Create a GEP which points just after the first entry in the VFTable,
1699 // this should be the location of the first virtual method.
1700 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1701 VTable->getValueType(), VTable, GEPIndices);
1702 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1703 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1705 C->setSelectionKind(llvm::Comdat::Largest);
1707 VFTable = llvm::GlobalAlias::create(
1708 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1709 VFTableName.str(), VTableGEP, &CGM.getModule());
1710 VFTable->setUnnamedAddr(true);
1712 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1713 // be referencing any RTTI data.
1714 // The GlobalVariable will end up being an appropriate definition of the
1719 VTable->setComdat(C);
1721 if (RD->hasAttr<DLLImportAttr>())
1722 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1723 else if (RD->hasAttr<DLLExportAttr>())
1724 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1726 VFTablesMap[ID] = VFTable;
1730 // Compute the identity of the most derived class whose virtual table is located
1731 // at the given offset into RD.
1732 static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx,
1733 const CXXRecordDecl *RD,
1735 if (Offset.isZero())
1738 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
1739 const CXXRecordDecl *MaxBase = nullptr;
1740 CharUnits MaxBaseOffset;
1741 for (auto &&B : RD->bases()) {
1742 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1743 CharUnits BaseOffset = Layout.getBaseClassOffset(Base);
1744 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1746 MaxBaseOffset = BaseOffset;
1749 for (auto &&B : RD->vbases()) {
1750 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1751 CharUnits BaseOffset = Layout.getVBaseClassOffset(Base);
1752 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1754 MaxBaseOffset = BaseOffset;
1758 return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset);
1761 // Compute the identity of the most derived class whose virtual table is located
1762 // at the MethodVFTableLocation ML.
1763 static const CXXRecordDecl *
1764 getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD,
1765 MicrosoftVTableContext::MethodVFTableLocation &ML) {
1766 const CXXRecordDecl *RD = ML.VBase;
1768 RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
1770 return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset);
1773 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1777 SourceLocation Loc) {
1778 GD = GD.getCanonicalDecl();
1779 CGBuilderTy &Builder = CGF.Builder;
1781 Ty = Ty->getPointerTo()->getPointerTo();
1783 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1784 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1786 MicrosoftVTableContext::MethodVFTableLocation ML =
1787 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1788 if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
1789 CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML),
1790 VTable, CodeGenFunction::CFITCK_VCall, Loc);
1792 llvm::Value *VFuncPtr =
1793 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1794 return Builder.CreateLoad(VFuncPtr);
1797 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1798 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1799 llvm::Value *This, const CXXMemberCallExpr *CE) {
1800 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1801 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1803 // We have only one destructor in the vftable but can get both behaviors
1804 // by passing an implicit int parameter.
1805 GlobalDecl GD(Dtor, Dtor_Deleting);
1806 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1807 Dtor, StructorType::Deleting);
1808 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1809 llvm::Value *Callee = getVirtualFunctionPointer(
1810 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1812 ASTContext &Context = getContext();
1813 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1814 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1815 DtorType == Dtor_Deleting);
1817 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1818 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1819 ImplicitParam, Context.IntTy, CE,
1820 StructorType::Deleting);
1821 return RV.getScalarVal();
1824 const VBTableGlobals &
1825 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1826 // At this layer, we can key the cache off of a single class, which is much
1827 // easier than caching each vbtable individually.
1828 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1830 std::tie(Entry, Added) =
1831 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1832 VBTableGlobals &VBGlobals = Entry->second;
1836 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1837 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1839 // Cache the globals for all vbtables so we don't have to recompute the
1841 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1842 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1843 E = VBGlobals.VBTables->end();
1845 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1851 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1852 const CXXMethodDecl *MD,
1853 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1854 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1855 "can't form pointers to ctors or virtual dtors");
1857 // Calculate the mangled name.
1858 SmallString<256> ThunkName;
1859 llvm::raw_svector_ostream Out(ThunkName);
1860 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1862 // If the thunk has been generated previously, just return it.
1863 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1864 return cast<llvm::Function>(GV);
1866 // Create the llvm::Function.
1867 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1868 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1869 llvm::Function *ThunkFn =
1870 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1871 ThunkName.str(), &CGM.getModule());
1872 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1874 ThunkFn->setLinkage(MD->isExternallyVisible()
1875 ? llvm::GlobalValue::LinkOnceODRLinkage
1876 : llvm::GlobalValue::InternalLinkage);
1877 if (MD->isExternallyVisible())
1878 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1880 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1881 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1883 // Add the "thunk" attribute so that LLVM knows that the return type is
1884 // meaningless. These thunks can be used to call functions with differing
1885 // return types, and the caller is required to cast the prototype
1886 // appropriately to extract the correct value.
1887 ThunkFn->addFnAttr("thunk");
1889 // These thunks can be compared, so they are not unnamed.
1890 ThunkFn->setUnnamedAddr(false);
1893 CodeGenFunction CGF(CGM);
1894 CGF.CurGD = GlobalDecl(MD);
1895 CGF.CurFuncIsThunk = true;
1897 // Build FunctionArgs, but only include the implicit 'this' parameter
1899 FunctionArgList FunctionArgs;
1900 buildThisParam(CGF, FunctionArgs);
1902 // Start defining the function.
1903 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1904 FunctionArgs, MD->getLocation(), SourceLocation());
1907 // Load the vfptr and then callee from the vftable. The callee should have
1908 // adjusted 'this' so that the vfptr is at offset zero.
1909 llvm::Value *VTable = CGF.GetVTablePtr(
1910 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1911 llvm::Value *VFuncPtr =
1912 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1913 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1915 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1920 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1921 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1922 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1923 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1924 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1925 if (GV->isDeclaration())
1926 emitVBTableDefinition(*VBT, RD, GV);
1930 llvm::GlobalVariable *
1931 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1932 llvm::GlobalVariable::LinkageTypes Linkage) {
1933 SmallString<256> OutName;
1934 llvm::raw_svector_ostream Out(OutName);
1935 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1936 StringRef Name = OutName.str();
1938 llvm::ArrayType *VBTableType =
1939 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1941 assert(!CGM.getModule().getNamedGlobal(Name) &&
1942 "vbtable with this name already exists: mangling bug?");
1943 llvm::GlobalVariable *GV =
1944 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1945 GV->setUnnamedAddr(true);
1947 if (RD->hasAttr<DLLImportAttr>())
1948 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1949 else if (RD->hasAttr<DLLExportAttr>())
1950 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1952 if (!GV->hasExternalLinkage())
1953 emitVBTableDefinition(VBT, RD, GV);
1958 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1959 const CXXRecordDecl *RD,
1960 llvm::GlobalVariable *GV) const {
1961 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1963 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1964 "should only emit vbtables for classes with vbtables");
1966 const ASTRecordLayout &BaseLayout =
1967 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1968 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1970 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1973 // The offset from ReusingBase's vbptr to itself always leads.
1974 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1975 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1977 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1978 for (const auto &I : ReusingBase->vbases()) {
1979 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1980 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1981 assert(!Offset.isNegative());
1983 // Make it relative to the subobject vbptr.
1984 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1985 if (VBT.getVBaseWithVPtr())
1986 CompleteVBPtrOffset +=
1987 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1988 Offset -= CompleteVBPtrOffset;
1990 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1991 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1992 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1995 assert(Offsets.size() ==
1996 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1997 ->getElementType())->getNumElements());
1998 llvm::ArrayType *VBTableType =
1999 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
2000 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
2001 GV->setInitializer(Init);
2004 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
2006 const ThisAdjustment &TA) {
2010 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
2012 if (!TA.Virtual.isEmpty()) {
2013 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
2014 // Adjust the this argument based on the vtordisp value.
2015 llvm::Value *VtorDispPtr =
2016 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
2018 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
2019 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
2020 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
2022 if (TA.Virtual.Microsoft.VBPtrOffset) {
2023 // If the final overrider is defined in a virtual base other than the one
2024 // that holds the vfptr, we have to use a vtordispex thunk which looks up
2025 // the vbtable of the derived class.
2026 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
2027 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
2029 llvm::Value *VBaseOffset =
2030 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
2031 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
2032 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2036 if (TA.NonVirtual) {
2037 // Non-virtual adjustment might result in a pointer outside the allocated
2038 // object, e.g. if the final overrider class is laid out after the virtual
2039 // base that declares a method in the most derived class.
2040 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
2043 // Don't need to bitcast back, the call CodeGen will handle this.
2048 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
2049 const ReturnAdjustment &RA) {
2053 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
2055 if (RA.Virtual.Microsoft.VBIndex) {
2056 assert(RA.Virtual.Microsoft.VBIndex > 0);
2057 const ASTContext &Context = getContext();
2058 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
2060 llvm::Value *VBaseOffset =
2061 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
2062 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
2063 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2067 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
2069 // Cast back to the original type.
2070 return CGF.Builder.CreateBitCast(V, Ret->getType());
2073 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
2074 QualType elementType) {
2075 // Microsoft seems to completely ignore the possibility of a
2076 // two-argument usual deallocation function.
2077 return elementType.isDestructedType();
2080 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
2081 // Microsoft seems to completely ignore the possibility of a
2082 // two-argument usual deallocation function.
2083 return expr->getAllocatedType().isDestructedType();
2086 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2087 // The array cookie is always a size_t; we then pad that out to the
2088 // alignment of the element type.
2089 ASTContext &Ctx = getContext();
2090 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2091 Ctx.getTypeAlignInChars(type));
2094 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2095 llvm::Value *allocPtr,
2096 CharUnits cookieSize) {
2097 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
2098 llvm::Value *numElementsPtr =
2099 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
2100 return CGF.Builder.CreateLoad(numElementsPtr);
2103 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2104 llvm::Value *newPtr,
2105 llvm::Value *numElements,
2106 const CXXNewExpr *expr,
2107 QualType elementType) {
2108 assert(requiresArrayCookie(expr));
2110 // The size of the cookie.
2111 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2113 // Compute an offset to the cookie.
2114 llvm::Value *cookiePtr = newPtr;
2116 // Write the number of elements into the appropriate slot.
2117 unsigned AS = newPtr->getType()->getPointerAddressSpace();
2118 llvm::Value *numElementsPtr
2119 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
2120 CGF.Builder.CreateStore(numElements, numElementsPtr);
2122 // Finally, compute a pointer to the actual data buffer by skipping
2123 // over the cookie completely.
2124 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
2125 cookieSize.getQuantity());
2128 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2129 llvm::Constant *Dtor,
2130 llvm::Constant *Addr) {
2131 // Create a function which calls the destructor.
2132 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2134 // extern "C" int __tlregdtor(void (*f)(void));
2135 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2136 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2138 llvm::Constant *TLRegDtor =
2139 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
2140 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2141 TLRegDtorFn->setDoesNotThrow();
2143 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2146 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2147 llvm::Constant *Dtor,
2148 llvm::Constant *Addr) {
2150 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2152 // The default behavior is to use atexit.
2153 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2156 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2158 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
2160 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2161 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
2162 // This will create a GV in the .CRT$XDU section. It will point to our
2163 // initialization function. The CRT will call all of these function
2164 // pointers at start-up time and, eventually, at thread-creation time.
2165 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2166 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2167 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2168 llvm::GlobalVariable::InternalLinkage, InitFunc,
2169 Twine(InitFunc->getName(), "$initializer$"));
2170 InitFuncPtr->setSection(".CRT$XDU");
2171 // This variable has discardable linkage, we have to add it to @llvm.used to
2172 // ensure it won't get discarded.
2173 CGM.addUsedGlobal(InitFuncPtr);
2177 std::vector<llvm::Function *> NonComdatInits;
2178 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2179 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
2180 llvm::Function *F = CXXThreadLocalInits[I];
2182 // If the GV is already in a comdat group, then we have to join it.
2183 if (llvm::Comdat *C = GV->getComdat())
2184 AddToXDU(F)->setComdat(C);
2186 NonComdatInits.push_back(F);
2189 if (!NonComdatInits.empty()) {
2190 llvm::FunctionType *FTy =
2191 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2192 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2193 FTy, "__tls_init", SourceLocation(),
2195 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2201 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2203 QualType LValType) {
2204 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2208 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2209 StringRef VarName("_Init_thread_epoch");
2210 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2212 auto *GV = new llvm::GlobalVariable(
2213 CGM.getModule(), CGM.IntTy,
2214 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2215 /*Initializer=*/nullptr, VarName,
2216 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2217 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2221 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2222 llvm::FunctionType *FTy =
2223 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2224 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2225 return CGM.CreateRuntimeFunction(
2226 FTy, "_Init_thread_header",
2227 llvm::AttributeSet::get(CGM.getLLVMContext(),
2228 llvm::AttributeSet::FunctionIndex,
2229 llvm::Attribute::NoUnwind));
2232 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2233 llvm::FunctionType *FTy =
2234 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2235 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2236 return CGM.CreateRuntimeFunction(
2237 FTy, "_Init_thread_footer",
2238 llvm::AttributeSet::get(CGM.getLLVMContext(),
2239 llvm::AttributeSet::FunctionIndex,
2240 llvm::Attribute::NoUnwind));
2243 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2244 llvm::FunctionType *FTy =
2245 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2246 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2247 return CGM.CreateRuntimeFunction(
2248 FTy, "_Init_thread_abort",
2249 llvm::AttributeSet::get(CGM.getLLVMContext(),
2250 llvm::AttributeSet::FunctionIndex,
2251 llvm::Attribute::NoUnwind));
2255 struct ResetGuardBit final : EHScopeStack::Cleanup {
2256 llvm::GlobalVariable *Guard;
2258 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2259 : Guard(Guard), GuardNum(GuardNum) {}
2261 void Emit(CodeGenFunction &CGF, Flags flags) override {
2262 // Reset the bit in the mask so that the static variable may be
2264 CGBuilderTy &Builder = CGF.Builder;
2265 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2266 llvm::ConstantInt *Mask =
2267 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2268 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2272 struct CallInitThreadAbort final : EHScopeStack::Cleanup {
2273 llvm::GlobalVariable *Guard;
2274 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2276 void Emit(CodeGenFunction &CGF, Flags flags) override {
2277 // Calling _Init_thread_abort will reset the guard's state.
2278 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2283 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2284 llvm::GlobalVariable *GV,
2286 // MSVC only uses guards for static locals.
2287 if (!D.isStaticLocal()) {
2288 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2289 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2290 llvm::Function *F = CGF.CurFn;
2291 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2292 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2293 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2297 bool ThreadlocalStatic = D.getTLSKind();
2298 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2300 // Thread-safe static variables which aren't thread-specific have a
2301 // per-variable guard.
2302 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2304 CGBuilderTy &Builder = CGF.Builder;
2305 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2306 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2308 // Get the guard variable for this function if we have one already.
2309 GuardInfo *GI = nullptr;
2310 if (ThreadlocalStatic)
2311 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2312 else if (!ThreadsafeStatic)
2313 GI = &GuardVariableMap[D.getDeclContext()];
2315 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2317 if (D.isExternallyVisible()) {
2318 // Externally visible variables have to be numbered in Sema to properly
2319 // handle unreachable VarDecls.
2320 GuardNum = getContext().getStaticLocalNumber(&D);
2321 assert(GuardNum > 0);
2323 } else if (HasPerVariableGuard) {
2324 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2326 // Non-externally visible variables are numbered here in CodeGen.
2327 GuardNum = GI->BitIndex++;
2330 if (!HasPerVariableGuard && GuardNum >= 32) {
2331 if (D.isExternallyVisible())
2332 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2338 // Mangle the name for the guard.
2339 SmallString<256> GuardName;
2341 llvm::raw_svector_ostream Out(GuardName);
2342 if (HasPerVariableGuard)
2343 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2346 getMangleContext().mangleStaticGuardVariable(&D, Out);
2349 // Create the guard variable with a zero-initializer. Just absorb linkage,
2350 // visibility and dll storage class from the guarded variable.
2352 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2353 GV->getLinkage(), Zero, GuardName.str());
2354 GuardVar->setVisibility(GV->getVisibility());
2355 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2356 if (GuardVar->isWeakForLinker())
2357 GuardVar->setComdat(
2358 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2360 GuardVar->setThreadLocal(true);
2361 if (GI && !HasPerVariableGuard)
2362 GI->Guard = GuardVar;
2365 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2366 "static local from the same function had different linkage");
2368 if (!HasPerVariableGuard) {
2369 // Pseudo code for the test:
2370 // if (!(GuardVar & MyGuardBit)) {
2371 // GuardVar |= MyGuardBit;
2372 // ... initialize the object ...;
2375 // Test our bit from the guard variable.
2376 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2377 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2378 llvm::Value *IsInitialized =
2379 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2380 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2381 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2382 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2384 // Set our bit in the guard variable and emit the initializer and add a global
2385 // destructor if appropriate.
2386 CGF.EmitBlock(InitBlock);
2387 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2388 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2389 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2390 CGF.PopCleanupBlock();
2391 Builder.CreateBr(EndBlock);
2394 CGF.EmitBlock(EndBlock);
2396 // Pseudo code for the test:
2397 // if (TSS > _Init_thread_epoch) {
2398 // _Init_thread_header(&TSS);
2400 // ... initialize the object ...;
2401 // _Init_thread_footer(&TSS);
2405 // The algorithm is almost identical to what can be found in the appendix
2408 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2410 // This BasicBLock determines whether or not we have any work to do.
2411 llvm::LoadInst *FirstGuardLoad =
2412 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2413 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2414 llvm::LoadInst *InitThreadEpoch =
2415 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2416 llvm::Value *IsUninitialized =
2417 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2418 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2419 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2420 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2422 // This BasicBlock attempts to determine whether or not this thread is
2423 // responsible for doing the initialization.
2424 CGF.EmitBlock(AttemptInitBlock);
2425 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2426 llvm::LoadInst *SecondGuardLoad =
2427 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2428 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2429 llvm::Value *ShouldDoInit =
2430 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2431 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2432 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2434 // Ok, we ended up getting selected as the initializing thread.
2435 CGF.EmitBlock(InitBlock);
2436 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2437 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2438 CGF.PopCleanupBlock();
2439 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2440 Builder.CreateBr(EndBlock);
2442 CGF.EmitBlock(EndBlock);
2446 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2447 // Null-ness for function memptrs only depends on the first field, which is
2448 // the function pointer. The rest don't matter, so we can zero initialize.
2449 if (MPT->isMemberFunctionPointer())
2452 // The virtual base adjustment field is always -1 for null, so if we have one
2453 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2454 // valid field offset.
2455 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2456 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2457 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2458 RD->nullFieldOffsetIsZero());
2462 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2463 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2464 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2465 llvm::SmallVector<llvm::Type *, 4> fields;
2466 if (MPT->isMemberFunctionPointer())
2467 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2469 fields.push_back(CGM.IntTy); // FieldOffset
2471 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2473 fields.push_back(CGM.IntTy);
2474 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2475 fields.push_back(CGM.IntTy);
2476 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2477 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2479 if (fields.size() == 1)
2481 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2484 void MicrosoftCXXABI::
2485 GetNullMemberPointerFields(const MemberPointerType *MPT,
2486 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2487 assert(fields.empty());
2488 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2489 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2490 if (MPT->isMemberFunctionPointer()) {
2491 // FunctionPointerOrVirtualThunk
2492 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2494 if (RD->nullFieldOffsetIsZero())
2495 fields.push_back(getZeroInt()); // FieldOffset
2497 fields.push_back(getAllOnesInt()); // FieldOffset
2500 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2502 fields.push_back(getZeroInt());
2503 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2504 fields.push_back(getZeroInt());
2505 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2506 fields.push_back(getAllOnesInt());
2510 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2511 llvm::SmallVector<llvm::Constant *, 4> fields;
2512 GetNullMemberPointerFields(MPT, fields);
2513 if (fields.size() == 1)
2515 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2516 assert(Res->getType() == ConvertMemberPointerType(MPT));
2521 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2522 bool IsMemberFunction,
2523 const CXXRecordDecl *RD,
2524 CharUnits NonVirtualBaseAdjustment,
2525 unsigned VBTableIndex) {
2526 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2528 // Single inheritance class member pointer are represented as scalars instead
2530 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2533 llvm::SmallVector<llvm::Constant *, 4> fields;
2534 fields.push_back(FirstField);
2536 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2537 fields.push_back(llvm::ConstantInt::get(
2538 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2540 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2541 CharUnits Offs = CharUnits::Zero();
2543 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2544 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2547 // The rest of the fields are adjusted by conversions to a more derived class.
2548 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2549 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2551 return llvm::ConstantStruct::getAnon(fields);
2555 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2557 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2558 if (RD->getMSInheritanceModel() ==
2559 MSInheritanceAttr::Keyword_virtual_inheritance)
2560 offset -= getContext().getOffsetOfBaseWithVBPtr(RD);
2561 llvm::Constant *FirstField =
2562 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2563 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2564 CharUnits::Zero(), /*VBTableIndex=*/0);
2567 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2569 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2570 const ValueDecl *MPD = MP.getMemberPointerDecl();
2572 return EmitNullMemberPointer(DstTy);
2574 ASTContext &Ctx = getContext();
2575 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2578 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2579 C = EmitMemberFunctionPointer(MD);
2581 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2582 C = EmitMemberDataPointer(DstTy, FieldOffset);
2585 if (!MemberPointerPath.empty()) {
2586 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2587 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2588 const MemberPointerType *SrcTy =
2589 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2590 ->castAs<MemberPointerType>();
2592 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2593 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2594 const CXXRecordDecl *PrevRD = SrcRD;
2595 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2596 const CXXRecordDecl *Base = nullptr;
2597 const CXXRecordDecl *Derived = nullptr;
2598 if (DerivedMember) {
2605 for (const CXXBaseSpecifier &BS : Derived->bases())
2606 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2607 Base->getCanonicalDecl())
2608 DerivedToBasePath.push_back(&BS);
2611 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2613 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2614 : CK_BaseToDerivedMemberPointer;
2615 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2616 DerivedToBasePath.end(), C);
2622 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2623 assert(MD->isInstance() && "Member function must not be static!");
2625 MD = MD->getCanonicalDecl();
2626 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2627 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2628 CodeGenTypes &Types = CGM.getTypes();
2630 unsigned VBTableIndex = 0;
2631 llvm::Constant *FirstField;
2632 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2633 if (!MD->isVirtual()) {
2635 // Check whether the function has a computable LLVM signature.
2636 if (Types.isFuncTypeConvertible(FPT)) {
2637 // The function has a computable LLVM signature; use the correct type.
2638 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2640 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2641 // function type is incomplete.
2644 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2646 auto &VTableContext = CGM.getMicrosoftVTableContext();
2647 MicrosoftVTableContext::MethodVFTableLocation ML =
2648 VTableContext.getMethodVFTableLocation(MD);
2649 FirstField = EmitVirtualMemPtrThunk(MD, ML);
2650 // Include the vfptr adjustment if the method is in a non-primary vftable.
2651 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2653 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2656 if (VBTableIndex == 0 &&
2657 RD->getMSInheritanceModel() ==
2658 MSInheritanceAttr::Keyword_virtual_inheritance)
2659 NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD);
2661 // The rest of the fields are common with data member pointers.
2662 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2663 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2664 NonVirtualBaseAdjustment, VBTableIndex);
2667 /// Member pointers are the same if they're either bitwise identical *or* both
2668 /// null. Null-ness for function members is determined by the first field,
2669 /// while for data member pointers we must compare all fields.
2671 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2674 const MemberPointerType *MPT,
2676 CGBuilderTy &Builder = CGF.Builder;
2678 // Handle != comparisons by switching the sense of all boolean operations.
2679 llvm::ICmpInst::Predicate Eq;
2680 llvm::Instruction::BinaryOps And, Or;
2682 Eq = llvm::ICmpInst::ICMP_NE;
2683 And = llvm::Instruction::Or;
2684 Or = llvm::Instruction::And;
2686 Eq = llvm::ICmpInst::ICMP_EQ;
2687 And = llvm::Instruction::And;
2688 Or = llvm::Instruction::Or;
2691 // If this is a single field member pointer (single inheritance), this is a
2693 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2694 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2695 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2697 return Builder.CreateICmp(Eq, L, R);
2699 // Compare the first field.
2700 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2701 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2702 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2704 // Compare everything other than the first field.
2705 llvm::Value *Res = nullptr;
2706 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2707 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2708 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2709 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2710 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2712 Res = Builder.CreateBinOp(And, Res, Cmp);
2717 // Check if the first field is 0 if this is a function pointer.
2718 if (MPT->isMemberFunctionPointer()) {
2719 // (l1 == r1 && ...) || l0 == 0
2720 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2721 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2722 Res = Builder.CreateBinOp(Or, Res, IsZero);
2725 // Combine the comparison of the first field, which must always be true for
2726 // this comparison to succeeed.
2727 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2731 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2732 llvm::Value *MemPtr,
2733 const MemberPointerType *MPT) {
2734 CGBuilderTy &Builder = CGF.Builder;
2735 llvm::SmallVector<llvm::Constant *, 4> fields;
2736 // We only need one field for member functions.
2737 if (MPT->isMemberFunctionPointer())
2738 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2740 GetNullMemberPointerFields(MPT, fields);
2741 assert(!fields.empty());
2742 llvm::Value *FirstField = MemPtr;
2743 if (MemPtr->getType()->isStructTy())
2744 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2745 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2747 // For function member pointers, we only need to test the function pointer
2748 // field. The other fields if any can be garbage.
2749 if (MPT->isMemberFunctionPointer())
2752 // Otherwise, emit a series of compares and combine the results.
2753 for (int I = 1, E = fields.size(); I < E; ++I) {
2754 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2755 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2756 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2761 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2762 llvm::Constant *Val) {
2763 // Function pointers are null if the pointer in the first field is null.
2764 if (MPT->isMemberFunctionPointer()) {
2765 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2766 Val->getAggregateElement(0U) : Val;
2767 return FirstField->isNullValue();
2770 // If it's not a function pointer and it's zero initializable, we can easily
2772 if (isZeroInitializable(MPT) && Val->isNullValue())
2775 // Otherwise, break down all the fields for comparison. Hopefully these
2776 // little Constants are reused, while a big null struct might not be.
2777 llvm::SmallVector<llvm::Constant *, 4> Fields;
2778 GetNullMemberPointerFields(MPT, Fields);
2779 if (Fields.size() == 1) {
2780 assert(Val->getType()->isIntegerTy());
2781 return Val == Fields[0];
2785 for (I = 0, E = Fields.size(); I != E; ++I) {
2786 if (Val->getAggregateElement(I) != Fields[I])
2793 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2795 llvm::Value *VBPtrOffset,
2796 llvm::Value *VBTableOffset,
2797 llvm::Value **VBPtrOut) {
2798 CGBuilderTy &Builder = CGF.Builder;
2799 // Load the vbtable pointer from the vbptr in the instance.
2800 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2801 llvm::Value *VBPtr =
2802 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2803 if (VBPtrOut) *VBPtrOut = VBPtr;
2804 VBPtr = Builder.CreateBitCast(VBPtr,
2805 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2806 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2808 // Translate from byte offset to table index. It improves analyzability.
2809 llvm::Value *VBTableIndex = Builder.CreateAShr(
2810 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2811 "vbtindex", /*isExact=*/true);
2813 // Load an i32 offset from the vb-table.
2814 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2815 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2816 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2819 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2821 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2822 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2823 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2824 CGBuilderTy &Builder = CGF.Builder;
2825 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2826 llvm::BasicBlock *OriginalBB = nullptr;
2827 llvm::BasicBlock *SkipAdjustBB = nullptr;
2828 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2830 // In the unspecified inheritance model, there might not be a vbtable at all,
2831 // in which case we need to skip the virtual base lookup. If there is a
2832 // vbtable, the first entry is a no-op entry that gives back the original
2833 // base, so look for a virtual base adjustment offset of zero.
2835 OriginalBB = Builder.GetInsertBlock();
2836 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2837 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2838 llvm::Value *IsVirtual =
2839 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2841 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2842 CGF.EmitBlock(VBaseAdjustBB);
2845 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2846 // know the vbptr offset.
2848 CharUnits offs = CharUnits::Zero();
2849 if (!RD->hasDefinition()) {
2850 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2851 unsigned DiagID = Diags.getCustomDiagID(
2852 DiagnosticsEngine::Error,
2853 "member pointer representation requires a "
2854 "complete class type for %0 to perform this expression");
2855 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2856 } else if (RD->getNumVBases())
2857 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2858 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2860 llvm::Value *VBPtr = nullptr;
2861 llvm::Value *VBaseOffs =
2862 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2863 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2865 // Merge control flow with the case where we didn't have to adjust.
2866 if (VBaseAdjustBB) {
2867 Builder.CreateBr(SkipAdjustBB);
2868 CGF.EmitBlock(SkipAdjustBB);
2869 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2870 Phi->addIncoming(Base, OriginalBB);
2871 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2874 return AdjustedBase;
2877 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2878 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2879 const MemberPointerType *MPT) {
2880 assert(MPT->isMemberDataPointer());
2881 unsigned AS = Base->getType()->getPointerAddressSpace();
2883 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2884 CGBuilderTy &Builder = CGF.Builder;
2885 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2886 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2888 // Extract the fields we need, regardless of model. We'll apply them if we
2890 llvm::Value *FieldOffset = MemPtr;
2891 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2892 llvm::Value *VBPtrOffset = nullptr;
2893 if (MemPtr->getType()->isStructTy()) {
2894 // We need to extract values.
2896 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2897 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2898 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2899 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2900 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2903 if (VirtualBaseAdjustmentOffset) {
2904 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2909 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2911 // Apply the offset, which we assume is non-null.
2913 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2915 // Cast the address to the appropriate pointer type, adopting the address
2916 // space of the base pointer.
2917 return Builder.CreateBitCast(Addr, PType);
2921 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2924 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2925 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2926 E->getCastKind() == CK_ReinterpretMemberPointer);
2928 // Use constant emission if we can.
2929 if (isa<llvm::Constant>(Src))
2930 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2932 // We may be adding or dropping fields from the member pointer, so we need
2933 // both types and the inheritance models of both records.
2934 const MemberPointerType *SrcTy =
2935 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2936 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2937 bool IsFunc = SrcTy->isMemberFunctionPointer();
2939 // If the classes use the same null representation, reinterpret_cast is a nop.
2940 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2941 if (IsReinterpret && IsFunc)
2944 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2945 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2946 if (IsReinterpret &&
2947 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2950 CGBuilderTy &Builder = CGF.Builder;
2952 // Branch past the conversion if Src is null.
2953 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2954 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2956 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2957 // pointer value of the destination type.
2958 if (IsReinterpret) {
2959 // For reinterpret casts, sema ensures that src and dst are both functions
2960 // or data and have the same size, which means the LLVM types should match.
2961 assert(Src->getType() == DstNull->getType());
2962 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2965 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2966 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2967 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2968 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2969 CGF.EmitBlock(ConvertBB);
2971 llvm::Value *Dst = EmitNonNullMemberPointerConversion(
2972 SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src,
2975 Builder.CreateBr(ContinueBB);
2977 // In the continuation, choose between DstNull and Dst.
2978 CGF.EmitBlock(ContinueBB);
2979 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2980 Phi->addIncoming(DstNull, OriginalBB);
2981 Phi->addIncoming(Dst, ConvertBB);
2985 llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion(
2986 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
2987 CastExpr::path_const_iterator PathBegin,
2988 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
2989 CGBuilderTy &Builder) {
2990 const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2991 const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2992 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2993 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2994 bool IsFunc = SrcTy->isMemberFunctionPointer();
2995 bool IsConstant = isa<llvm::Constant>(Src);
2998 llvm::Value *FirstField = Src;
2999 llvm::Value *NonVirtualBaseAdjustment = getZeroInt();
3000 llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt();
3001 llvm::Value *VBPtrOffset = getZeroInt();
3002 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
3003 // We need to extract values.
3005 FirstField = Builder.CreateExtractValue(Src, I++);
3006 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
3007 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
3008 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
3009 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
3010 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
3011 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
3014 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
3015 const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy;
3016 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
3018 // For data pointers, we adjust the field offset directly. For functions, we
3019 // have a separate field.
3020 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
3022 // The virtual inheritance model has a quirk: the virtual base table is always
3023 // referenced when dereferencing a member pointer even if the member pointer
3024 // is non-virtual. This is accounted for by adjusting the non-virtual offset
3025 // to point backwards to the top of the MDC from the first VBase. Undo this
3026 // adjustment to normalize the member pointer.
3027 llvm::Value *SrcVBIndexEqZero =
3028 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3029 if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3030 if (int64_t SrcOffsetToFirstVBase =
3031 getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) {
3032 llvm::Value *UndoSrcAdjustment = Builder.CreateSelect(
3034 llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase),
3036 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment);
3040 // A non-zero vbindex implies that we are dealing with a source member in a
3041 // floating virtual base in addition to some non-virtual offset. If the
3042 // vbindex is zero, we are dealing with a source that exists in a non-virtual,
3043 // fixed, base. The difference between these two cases is that the vbindex +
3044 // nvoffset *always* point to the member regardless of what context they are
3045 // evaluated in so long as the vbindex is adjusted. A member inside a fixed
3046 // base requires explicit nv adjustment.
3047 llvm::Constant *BaseClassOffset = llvm::ConstantInt::get(
3049 CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd)
3052 llvm::Value *NVDisp;
3053 if (IsDerivedToBase)
3054 NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj");
3056 NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj");
3058 NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt());
3060 // Update the vbindex to an appropriate value in the destination because
3061 // SrcRD's vbtable might not be a strict prefix of the one in DstRD.
3062 llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero;
3063 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) &&
3064 MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) {
3065 if (llvm::GlobalVariable *VDispMap =
3066 getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) {
3067 llvm::Value *VBIndex = Builder.CreateExactUDiv(
3068 VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4));
3070 llvm::Constant *Mapping = VDispMap->getInitializer();
3071 VirtualBaseAdjustmentOffset =
3072 Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex));
3074 llvm::Value *Idxs[] = {getZeroInt(), VBIndex};
3075 VirtualBaseAdjustmentOffset =
3076 Builder.CreateLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs));
3080 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3084 // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize
3085 // it to the offset of the vbptr.
3086 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) {
3087 llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get(
3089 getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity());
3091 Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset);
3094 // Likewise, apply a similar adjustment so that dereferencing the member
3095 // pointer correctly accounts for the distance between the start of the first
3096 // virtual base and the top of the MDC.
3097 if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3098 if (int64_t DstOffsetToFirstVBase =
3099 getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) {
3100 llvm::Value *DoDstAdjustment = Builder.CreateSelect(
3102 llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase),
3104 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment);
3108 // Recompose dst from the null struct and the adjusted fields from src.
3110 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
3113 Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy));
3115 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
3116 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3117 Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++);
3118 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3119 Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++);
3120 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3121 Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++);
3127 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
3128 llvm::Constant *Src) {
3129 const MemberPointerType *SrcTy =
3130 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3131 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3133 CastKind CK = E->getCastKind();
3135 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
3136 E->path_end(), Src);
3139 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
3140 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3141 CastExpr::path_const_iterator PathBegin,
3142 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
3143 assert(CK == CK_DerivedToBaseMemberPointer ||
3144 CK == CK_BaseToDerivedMemberPointer ||
3145 CK == CK_ReinterpretMemberPointer);
3146 // If src is null, emit a new null for dst. We can't return src because dst
3147 // might have a new representation.
3148 if (MemberPointerConstantIsNull(SrcTy, Src))
3149 return EmitNullMemberPointer(DstTy);
3151 // We don't need to do anything for reinterpret_casts of non-null member
3152 // pointers. We should only get here when the two type representations have
3154 if (CK == CK_ReinterpretMemberPointer)
3157 CGBuilderTy Builder(CGM.getLLVMContext());
3158 auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion(
3159 SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder));
3164 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3165 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
3166 llvm::Value *MemPtr, const MemberPointerType *MPT) {
3167 assert(MPT->isMemberFunctionPointer());
3168 const FunctionProtoType *FPT =
3169 MPT->getPointeeType()->castAs<FunctionProtoType>();
3170 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3171 llvm::FunctionType *FTy =
3172 CGM.getTypes().GetFunctionType(
3173 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
3174 CGBuilderTy &Builder = CGF.Builder;
3176 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3178 // Extract the fields we need, regardless of model. We'll apply them if we
3180 llvm::Value *FunctionPointer = MemPtr;
3181 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3182 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3183 llvm::Value *VBPtrOffset = nullptr;
3184 if (MemPtr->getType()->isStructTy()) {
3185 // We need to extract values.
3187 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3188 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3189 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3190 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3191 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3192 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3193 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3196 if (VirtualBaseAdjustmentOffset) {
3197 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
3201 if (NonVirtualBaseAdjustment) {
3202 // Apply the adjustment and cast back to the original struct type.
3203 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
3204 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3205 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
3208 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3211 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3212 return new MicrosoftCXXABI(CGM);
3215 // MS RTTI Overview:
3216 // The run time type information emitted by cl.exe contains 5 distinct types of
3217 // structures. Many of them reference each other.
3219 // TypeInfo: Static classes that are returned by typeid.
3221 // CompleteObjectLocator: Referenced by vftables. They contain information
3222 // required for dynamic casting, including OffsetFromTop. They also contain
3223 // a reference to the TypeInfo for the type and a reference to the
3224 // CompleteHierarchyDescriptor for the type.
3226 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3227 // Used during dynamic_cast to walk a class hierarchy. References a base
3228 // class array and the size of said array.
3230 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3231 // somewhat of a misnomer because the most derived class is also in the list
3232 // as well as multiple copies of virtual bases (if they occur multiple times
3233 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3234 // every path in the hierarchy, in pre-order depth first order. Note, we do
3235 // not declare a specific llvm type for BaseClassArray, it's merely an array
3236 // of BaseClassDescriptor pointers.
3238 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3239 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3240 // BaseClassArray is. It contains information about a class within a
3241 // hierarchy such as: is this base is ambiguous and what is its offset in the
3242 // vbtable. The names of the BaseClassDescriptors have all of their fields
3243 // mangled into them so they can be aggressively deduplicated by the linker.
3245 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3246 StringRef MangledName("\01??_7type_info@@6B@");
3247 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3249 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3251 llvm::GlobalVariable::ExternalLinkage,
3252 /*Initializer=*/nullptr, MangledName);
3257 /// \brief A Helper struct that stores information about a class in a class
3258 /// hierarchy. The information stored in these structs struct is used during
3259 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3260 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3261 // implicit depth first pre-order tree connectivity. getFirstChild and
3262 // getNextSibling allow us to walk the tree efficiently.
3263 struct MSRTTIClass {
3265 IsPrivateOnPath = 1 | 8,
3269 HasHierarchyDescriptor = 64
3271 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3272 uint32_t initialize(const MSRTTIClass *Parent,
3273 const CXXBaseSpecifier *Specifier);
3275 MSRTTIClass *getFirstChild() { return this + 1; }
3276 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3277 return Child + 1 + Child->NumBases;
3280 const CXXRecordDecl *RD, *VirtualRoot;
3281 uint32_t Flags, NumBases, OffsetInVBase;
3284 /// \brief Recursively initialize the base class array.
3285 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3286 const CXXBaseSpecifier *Specifier) {
3287 Flags = HasHierarchyDescriptor;
3289 VirtualRoot = nullptr;
3292 if (Specifier->getAccessSpecifier() != AS_public)
3293 Flags |= IsPrivate | IsPrivateOnPath;
3294 if (Specifier->isVirtual()) {
3299 if (Parent->Flags & IsPrivateOnPath)
3300 Flags |= IsPrivateOnPath;
3301 VirtualRoot = Parent->VirtualRoot;
3302 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3303 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3307 MSRTTIClass *Child = getFirstChild();
3308 for (const CXXBaseSpecifier &Base : RD->bases()) {
3309 NumBases += Child->initialize(this, &Base) + 1;
3310 Child = getNextChild(Child);
3315 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3316 switch (Ty->getLinkage()) {
3318 case InternalLinkage:
3319 case UniqueExternalLinkage:
3320 return llvm::GlobalValue::InternalLinkage;
3322 case VisibleNoLinkage:
3323 case ExternalLinkage:
3324 return llvm::GlobalValue::LinkOnceODRLinkage;
3326 llvm_unreachable("Invalid linkage!");
3329 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3330 /// calls to the module and information about the most derived class in a
3332 struct MSRTTIBuilder {
3334 HasBranchingHierarchy = 1,
3335 HasVirtualBranchingHierarchy = 2,
3336 HasAmbiguousBases = 4
3339 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3340 : CGM(ABI.CGM), Context(CGM.getContext()),
3341 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3342 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3345 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3346 llvm::GlobalVariable *
3347 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3348 llvm::GlobalVariable *getClassHierarchyDescriptor();
3349 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3352 ASTContext &Context;
3353 llvm::LLVMContext &VMContext;
3354 llvm::Module &Module;
3355 const CXXRecordDecl *RD;
3356 llvm::GlobalVariable::LinkageTypes Linkage;
3357 MicrosoftCXXABI &ABI;
3362 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3364 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3365 const CXXRecordDecl *RD) {
3366 Classes.push_back(MSRTTIClass(RD));
3367 for (const CXXBaseSpecifier &Base : RD->bases())
3368 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3371 /// \brief Find ambiguity among base classes.
3373 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3374 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3375 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3376 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3377 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3378 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3379 !VirtualBases.insert(Class->RD).second) {
3380 Class = MSRTTIClass::getNextChild(Class);
3383 if (!UniqueBases.insert(Class->RD).second)
3384 AmbiguousBases.insert(Class->RD);
3387 if (AmbiguousBases.empty())
3389 for (MSRTTIClass &Class : Classes)
3390 if (AmbiguousBases.count(Class.RD))
3391 Class.Flags |= MSRTTIClass::IsAmbiguous;
3394 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3395 SmallString<256> MangledName;
3397 llvm::raw_svector_ostream Out(MangledName);
3398 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3401 // Check to see if we've already declared this ClassHierarchyDescriptor.
3402 if (auto CHD = Module.getNamedGlobal(MangledName))
3405 // Serialize the class hierarchy and initialize the CHD Fields.
3406 SmallVector<MSRTTIClass, 8> Classes;
3407 serializeClassHierarchy(Classes, RD);
3408 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3409 detectAmbiguousBases(Classes);
3411 for (auto Class : Classes) {
3412 if (Class.RD->getNumBases() > 1)
3413 Flags |= HasBranchingHierarchy;
3414 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3415 // believe the field isn't actually used.
3416 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3417 Flags |= HasAmbiguousBases;
3419 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3420 Flags |= HasVirtualBranchingHierarchy;
3421 // These gep indices are used to get the address of the first element of the
3422 // base class array.
3423 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3424 llvm::ConstantInt::get(CGM.IntTy, 0)};
3426 // Forward-declare the class hierarchy descriptor
3427 auto Type = ABI.getClassHierarchyDescriptorType();
3428 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3429 /*Initializer=*/nullptr,
3430 StringRef(MangledName));
3431 if (CHD->isWeakForLinker())
3432 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3434 auto *Bases = getBaseClassArray(Classes);
3436 // Initialize the base class ClassHierarchyDescriptor.
3437 llvm::Constant *Fields[] = {
3438 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3439 llvm::ConstantInt::get(CGM.IntTy, Flags),
3440 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3441 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3442 Bases->getValueType(), Bases,
3443 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3445 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3449 llvm::GlobalVariable *
3450 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3451 SmallString<256> MangledName;
3453 llvm::raw_svector_ostream Out(MangledName);
3454 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3457 // Forward-declare the base class array.
3458 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3459 // mode) bytes of padding. We provide a pointer sized amount of padding by
3460 // adding +1 to Classes.size(). The sections have pointer alignment and are
3461 // marked pick-any so it shouldn't matter.
3462 llvm::Type *PtrType = ABI.getImageRelativeType(
3463 ABI.getBaseClassDescriptorType()->getPointerTo());
3464 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3466 new llvm::GlobalVariable(Module, ArrType,
3467 /*Constant=*/true, Linkage,
3468 /*Initializer=*/nullptr, StringRef(MangledName));
3469 if (BCA->isWeakForLinker())
3470 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3472 // Initialize the BaseClassArray.
3473 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3474 for (MSRTTIClass &Class : Classes)
3475 BaseClassArrayData.push_back(
3476 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3477 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3478 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3482 llvm::GlobalVariable *
3483 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3484 // Compute the fields for the BaseClassDescriptor. They are computed up front
3485 // because they are mangled into the name of the object.
3486 uint32_t OffsetInVBTable = 0;
3487 int32_t VBPtrOffset = -1;
3488 if (Class.VirtualRoot) {
3489 auto &VTableContext = CGM.getMicrosoftVTableContext();
3490 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3491 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3494 SmallString<256> MangledName;
3496 llvm::raw_svector_ostream Out(MangledName);
3497 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3498 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3502 // Check to see if we've already declared this object.
3503 if (auto BCD = Module.getNamedGlobal(MangledName))
3506 // Forward-declare the base class descriptor.
3507 auto Type = ABI.getBaseClassDescriptorType();
3509 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3510 /*Initializer=*/nullptr, StringRef(MangledName));
3511 if (BCD->isWeakForLinker())
3512 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3514 // Initialize the BaseClassDescriptor.
3515 llvm::Constant *Fields[] = {
3516 ABI.getImageRelativeConstant(
3517 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3518 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3519 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3520 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3521 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3522 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3523 ABI.getImageRelativeConstant(
3524 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3526 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3530 llvm::GlobalVariable *
3531 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3532 SmallString<256> MangledName;
3534 llvm::raw_svector_ostream Out(MangledName);
3535 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3538 // Check to see if we've already computed this complete object locator.
3539 if (auto COL = Module.getNamedGlobal(MangledName))
3542 // Compute the fields of the complete object locator.
3543 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3544 int VFPtrOffset = 0;
3545 // The offset includes the vtordisp if one exists.
3546 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3547 if (Context.getASTRecordLayout(RD)
3548 .getVBaseOffsetsMap()
3550 ->second.hasVtorDisp())
3551 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3553 // Forward-declare the complete object locator.
3554 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3555 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3556 /*Initializer=*/nullptr, StringRef(MangledName));
3558 // Initialize the CompleteObjectLocator.
3559 llvm::Constant *Fields[] = {
3560 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3561 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3562 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3563 ABI.getImageRelativeConstant(
3564 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3565 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3566 ABI.getImageRelativeConstant(COL),
3568 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3569 if (!ABI.isImageRelative())
3570 FieldsRef = FieldsRef.drop_back();
3571 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3572 if (COL->isWeakForLinker())
3573 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3577 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3578 bool &IsConst, bool &IsVolatile) {
3579 T = Context.getExceptionObjectType(T);
3581 // C++14 [except.handle]p3:
3582 // A handler is a match for an exception object of type E if [...]
3583 // - the handler is of type cv T or const T& where T is a pointer type and
3584 // E is a pointer type that can be converted to T by [...]
3585 // - a qualification conversion
3588 QualType PointeeType = T->getPointeeType();
3589 if (!PointeeType.isNull()) {
3590 IsConst = PointeeType.isConstQualified();
3591 IsVolatile = PointeeType.isVolatileQualified();
3594 // Member pointer types like "const int A::*" are represented by having RTTI
3595 // for "int A::*" and separately storing the const qualifier.
3596 if (const auto *MPTy = T->getAs<MemberPointerType>())
3597 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3600 // Pointer types like "const int * const *" are represented by having RTTI
3601 // for "const int **" and separately storing the const qualifier.
3602 if (T->isPointerType())
3603 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3609 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3610 QualType CatchHandlerType) {
3611 // TypeDescriptors for exceptions never have qualified pointer types,
3612 // qualifiers are stored seperately in order to support qualification
3614 bool IsConst, IsVolatile;
3615 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3617 bool IsReference = CatchHandlerType->isReferenceType();
3627 SmallString<256> MangledName;
3629 llvm::raw_svector_ostream Out(MangledName);
3630 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3633 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3634 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3636 llvm::Constant *Fields[] = {
3637 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3638 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3640 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3641 auto *Var = new llvm::GlobalVariable(
3642 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3643 llvm::GlobalValue::PrivateLinkage,
3644 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3645 StringRef(MangledName));
3646 Var->setUnnamedAddr(true);
3647 Var->setSection("llvm.metadata");
3651 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3652 /// llvm::GlobalVariable * because different type descriptors have different
3653 /// types, and need to be abstracted. They are abstracting by casting the
3654 /// address to an Int8PtrTy.
3655 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3656 SmallString<256> MangledName;
3658 llvm::raw_svector_ostream Out(MangledName);
3659 getMangleContext().mangleCXXRTTI(Type, Out);
3662 // Check to see if we've already declared this TypeDescriptor.
3663 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3664 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3666 // Compute the fields for the TypeDescriptor.
3667 SmallString<256> TypeInfoString;
3669 llvm::raw_svector_ostream Out(TypeInfoString);
3670 getMangleContext().mangleCXXRTTIName(Type, Out);
3673 // Declare and initialize the TypeDescriptor.
3674 llvm::Constant *Fields[] = {
3675 getTypeInfoVTable(CGM), // VFPtr
3676 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3677 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3678 llvm::StructType *TypeDescriptorType =
3679 getTypeDescriptorType(TypeInfoString);
3680 auto *Var = new llvm::GlobalVariable(
3681 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3682 getLinkageForRTTI(Type),
3683 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3684 StringRef(MangledName));
3685 if (Var->isWeakForLinker())
3686 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3687 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3690 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3691 llvm::GlobalVariable *
3692 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3693 const VPtrInfo *Info) {
3694 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3697 static void emitCXXConstructor(CodeGenModule &CGM,
3698 const CXXConstructorDecl *ctor,
3699 StructorType ctorType) {
3700 // There are no constructor variants, always emit the complete destructor.
3701 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3702 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3705 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3706 StructorType dtorType) {
3707 // The complete destructor is equivalent to the base destructor for
3708 // classes with no virtual bases, so try to emit it as an alias.
3709 if (!dtor->getParent()->getNumVBases() &&
3710 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3711 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3712 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3713 if (ProducedAlias) {
3714 if (dtorType == StructorType::Complete)
3716 if (dtor->isVirtual())
3717 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3721 // The base destructor is equivalent to the base destructor of its
3722 // base class if there is exactly one non-virtual base class with a
3723 // non-trivial destructor, there are no fields with a non-trivial
3724 // destructor, and the body of the destructor is trivial.
3725 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3728 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3729 if (Fn->isWeakForLinker())
3730 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3733 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3734 StructorType Type) {
3735 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3736 emitCXXConstructor(CGM, CD, Type);
3739 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3743 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3745 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3747 // Calculate the mangled name.
3748 SmallString<256> ThunkName;
3749 llvm::raw_svector_ostream Out(ThunkName);
3750 getMangleContext().mangleCXXCtor(CD, CT, Out);
3752 // If the thunk has been generated previously, just return it.
3753 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3754 return cast<llvm::Function>(GV);
3756 // Create the llvm::Function.
3757 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3758 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3759 const CXXRecordDecl *RD = CD->getParent();
3760 QualType RecordTy = getContext().getRecordType(RD);
3761 llvm::Function *ThunkFn = llvm::Function::Create(
3762 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3763 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3764 FnInfo.getEffectiveCallingConvention()));
3765 if (ThunkFn->isWeakForLinker())
3766 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
3767 bool IsCopy = CT == Ctor_CopyingClosure;
3770 CodeGenFunction CGF(CGM);
3771 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3773 // Build FunctionArgs.
3774 FunctionArgList FunctionArgs;
3776 // A constructor always starts with a 'this' pointer as its first argument.
3777 buildThisParam(CGF, FunctionArgs);
3779 // Following the 'this' pointer is a reference to the source object that we
3780 // are copying from.
3781 ImplicitParamDecl SrcParam(
3782 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3783 getContext().getLValueReferenceType(RecordTy,
3784 /*SpelledAsLValue=*/true));
3786 FunctionArgs.push_back(&SrcParam);
3788 // Constructors for classes which utilize virtual bases have an additional
3789 // parameter which indicates whether or not it is being delegated to by a more
3790 // derived constructor.
3791 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3792 &getContext().Idents.get("is_most_derived"),
3793 getContext().IntTy);
3794 // Only add the parameter to the list if thie class has virtual bases.
3795 if (RD->getNumVBases() > 0)
3796 FunctionArgs.push_back(&IsMostDerived);
3798 // Start defining the function.
3799 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3800 FunctionArgs, CD->getLocation(), SourceLocation());
3802 llvm::Value *This = getThisValue(CGF);
3804 llvm::Value *SrcVal =
3805 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3810 // Push the this ptr.
3811 Args.add(RValue::get(This), CD->getThisType(getContext()));
3813 // Push the src ptr.
3815 Args.add(RValue::get(SrcVal), SrcParam.getType());
3817 // Add the rest of the default arguments.
3818 std::vector<Stmt *> ArgVec;
3819 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3820 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3821 assert(DefaultArg && "sema forgot to instantiate default args");
3822 ArgVec.push_back(DefaultArg);
3825 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3827 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3828 CGF.EmitCallArgs(Args, FPT, llvm::makeArrayRef(ArgVec), CD, IsCopy ? 1 : 0);
3830 // Insert any ABI-specific implicit constructor arguments.
3831 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3832 /*ForVirtualBase=*/false,
3833 /*Delegating=*/false, Args);
3835 // Call the destructor with our arguments.
3836 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3837 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3838 Args, CD, Ctor_Complete, ExtraArgs);
3839 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3841 Cleanups.ForceCleanup();
3843 // Emit the ret instruction, remove any temporary instructions created for the
3845 CGF.FinishFunction(SourceLocation());
3850 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3852 int32_t VBPtrOffset,
3854 assert(!T->isReferenceType());
3856 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3857 const CXXConstructorDecl *CD =
3858 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3859 CXXCtorType CT = Ctor_Complete;
3861 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3862 CT = Ctor_CopyingClosure;
3864 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3865 SmallString<256> MangledName;
3867 llvm::raw_svector_ostream Out(MangledName);
3868 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3869 VBPtrOffset, VBIndex, Out);
3871 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3872 return getImageRelativeConstant(GV);
3874 // The TypeDescriptor is used by the runtime to determine if a catch handler
3875 // is appropriate for the exception object.
3876 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3878 // The runtime is responsible for calling the copy constructor if the
3879 // exception is caught by value.
3880 llvm::Constant *CopyCtor;
3882 if (CT == Ctor_CopyingClosure)
3883 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3885 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3887 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3889 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3891 CopyCtor = getImageRelativeConstant(CopyCtor);
3893 bool IsScalar = !RD;
3894 bool HasVirtualBases = false;
3895 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3896 QualType PointeeType = T;
3897 if (T->isPointerType())
3898 PointeeType = T->getPointeeType();
3899 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3900 HasVirtualBases = RD->getNumVBases() > 0;
3901 if (IdentifierInfo *II = RD->getIdentifier())
3902 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3905 // Encode the relevant CatchableType properties into the Flags bitfield.
3906 // FIXME: Figure out how bits 2 or 8 can get set.
3910 if (HasVirtualBases)
3915 llvm::Constant *Fields[] = {
3916 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3917 TD, // TypeDescriptor
3918 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3919 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3920 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3921 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3922 CopyCtor // CopyCtor
3924 llvm::StructType *CTType = getCatchableTypeType();
3925 auto *GV = new llvm::GlobalVariable(
3926 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3927 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3928 GV->setUnnamedAddr(true);
3929 GV->setSection(".xdata");
3930 if (GV->isWeakForLinker())
3931 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3932 return getImageRelativeConstant(GV);
3935 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3936 assert(!T->isReferenceType());
3938 // See if we've already generated a CatchableTypeArray for this type before.
3939 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3943 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3944 // using a SmallSetVector. Duplicates may arise due to virtual bases
3945 // occurring more than once in the hierarchy.
3946 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3948 // C++14 [except.handle]p3:
3949 // A handler is a match for an exception object of type E if [...]
3950 // - the handler is of type cv T or cv T& and T is an unambiguous public
3951 // base class of E, or
3952 // - the handler is of type cv T or const T& where T is a pointer type and
3953 // E is a pointer type that can be converted to T by [...]
3954 // - a standard pointer conversion (4.10) not involving conversions to
3955 // pointers to private or protected or ambiguous classes
3956 const CXXRecordDecl *MostDerivedClass = nullptr;
3957 bool IsPointer = T->isPointerType();
3959 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3961 MostDerivedClass = T->getAsCXXRecordDecl();
3963 // Collect all the unambiguous public bases of the MostDerivedClass.
3964 if (MostDerivedClass) {
3965 const ASTContext &Context = getContext();
3966 const ASTRecordLayout &MostDerivedLayout =
3967 Context.getASTRecordLayout(MostDerivedClass);
3968 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3969 SmallVector<MSRTTIClass, 8> Classes;
3970 serializeClassHierarchy(Classes, MostDerivedClass);
3971 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3972 detectAmbiguousBases(Classes);
3973 for (const MSRTTIClass &Class : Classes) {
3974 // Skip any ambiguous or private bases.
3976 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3978 // Write down how to convert from a derived pointer to a base pointer.
3979 uint32_t OffsetInVBTable = 0;
3980 int32_t VBPtrOffset = -1;
3981 if (Class.VirtualRoot) {
3983 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3984 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3987 // Turn our record back into a pointer if the exception object is a
3989 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3991 RTTITy = Context.getPointerType(RTTITy);
3992 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3993 VBPtrOffset, OffsetInVBTable));
3997 // C++14 [except.handle]p3:
3998 // A handler is a match for an exception object of type E if
3999 // - The handler is of type cv T or cv T& and E and T are the same type
4000 // (ignoring the top-level cv-qualifiers)
4001 CatchableTypes.insert(getCatchableType(T));
4003 // C++14 [except.handle]p3:
4004 // A handler is a match for an exception object of type E if
4005 // - the handler is of type cv T or const T& where T is a pointer type and
4006 // E is a pointer type that can be converted to T by [...]
4007 // - a standard pointer conversion (4.10) not involving conversions to
4008 // pointers to private or protected or ambiguous classes
4010 // C++14 [conv.ptr]p2:
4011 // A prvalue of type "pointer to cv T," where T is an object type, can be
4012 // converted to a prvalue of type "pointer to cv void".
4013 if (IsPointer && T->getPointeeType()->isObjectType())
4014 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4016 // C++14 [except.handle]p3:
4017 // A handler is a match for an exception object of type E if [...]
4018 // - the handler is of type cv T or const T& where T is a pointer or
4019 // pointer to member type and E is std::nullptr_t.
4021 // We cannot possibly list all possible pointer types here, making this
4022 // implementation incompatible with the standard. However, MSVC includes an
4023 // entry for pointer-to-void in this case. Let's do the same.
4024 if (T->isNullPtrType())
4025 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4027 uint32_t NumEntries = CatchableTypes.size();
4028 llvm::Type *CTType =
4029 getImageRelativeType(getCatchableTypeType()->getPointerTo());
4030 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
4031 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
4032 llvm::Constant *Fields[] = {
4033 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
4034 llvm::ConstantArray::get(
4035 AT, llvm::makeArrayRef(CatchableTypes.begin(),
4036 CatchableTypes.end())) // CatchableTypes
4038 SmallString<256> MangledName;
4040 llvm::raw_svector_ostream Out(MangledName);
4041 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
4043 CTA = new llvm::GlobalVariable(
4044 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
4045 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
4046 CTA->setUnnamedAddr(true);
4047 CTA->setSection(".xdata");
4048 if (CTA->isWeakForLinker())
4049 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
4053 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
4054 bool IsConst, IsVolatile;
4055 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
4057 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
4058 // the exception object may be caught as.
4059 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
4060 // The first field in a CatchableTypeArray is the number of CatchableTypes.
4061 // This is used as a component of the mangled name which means that we need to
4062 // know what it is in order to see if we have previously generated the
4064 uint32_t NumEntries =
4065 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
4066 ->getLimitedValue();
4068 SmallString<256> MangledName;
4070 llvm::raw_svector_ostream Out(MangledName);
4071 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
4075 // Reuse a previously generated ThrowInfo if we have generated an appropriate
4077 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
4080 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
4081 // be at least as CV qualified. Encode this requirement into the Flags
4089 // The cleanup-function (a destructor) must be called when the exception
4090 // object's lifetime ends.
4091 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
4092 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4093 if (CXXDestructorDecl *DtorD = RD->getDestructor())
4094 if (!DtorD->isTrivial())
4095 CleanupFn = llvm::ConstantExpr::getBitCast(
4096 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
4098 // This is unused as far as we can tell, initialize it to null.
4099 llvm::Constant *ForwardCompat =
4100 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
4101 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
4102 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
4103 llvm::StructType *TIType = getThrowInfoType();
4104 llvm::Constant *Fields[] = {
4105 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4106 getImageRelativeConstant(CleanupFn), // CleanupFn
4107 ForwardCompat, // ForwardCompat
4108 PointerToCatchableTypes // CatchableTypeArray
4110 auto *GV = new llvm::GlobalVariable(
4111 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
4112 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
4113 GV->setUnnamedAddr(true);
4114 GV->setSection(".xdata");
4115 if (GV->isWeakForLinker())
4116 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4120 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
4121 const Expr *SubExpr = E->getSubExpr();
4122 QualType ThrowType = SubExpr->getType();
4123 // The exception object lives on the stack and it's address is passed to the
4124 // runtime function.
4125 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
4126 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4129 // The so-called ThrowInfo is used to describe how the exception object may be
4131 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4133 // Call into the runtime to throw the exception.
4134 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
4135 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);