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);
261 StringRef MangledName = OutName.str();
263 if (auto *VDispMap = CGM.getModule().getNamedGlobal(MangledName))
266 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
267 unsigned NumEntries = 1 + SrcRD->getNumVBases();
268 SmallVector<llvm::Constant *, 4> Map(NumEntries,
269 llvm::UndefValue::get(CGM.IntTy));
270 Map[0] = llvm::ConstantInt::get(CGM.IntTy, 0);
271 bool AnyDifferent = false;
272 for (const auto &I : SrcRD->vbases()) {
273 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
274 if (!DstRD->isVirtuallyDerivedFrom(VBase))
277 unsigned SrcVBIndex = VTContext.getVBTableIndex(SrcRD, VBase);
278 unsigned DstVBIndex = VTContext.getVBTableIndex(DstRD, VBase);
279 Map[SrcVBIndex] = llvm::ConstantInt::get(CGM.IntTy, DstVBIndex * 4);
280 AnyDifferent |= SrcVBIndex != DstVBIndex;
282 // This map would be useless, don't use it.
286 llvm::ArrayType *VDispMapTy = llvm::ArrayType::get(CGM.IntTy, Map.size());
287 llvm::Constant *Init = llvm::ConstantArray::get(VDispMapTy, Map);
288 llvm::GlobalValue::LinkageTypes Linkage =
289 SrcRD->isExternallyVisible() && DstRD->isExternallyVisible()
290 ? llvm::GlobalValue::LinkOnceODRLinkage
291 : llvm::GlobalValue::InternalLinkage;
292 auto *VDispMap = new llvm::GlobalVariable(
293 CGM.getModule(), VDispMapTy, /*Constant=*/true, Linkage,
294 /*Initializer=*/Init, MangledName);
298 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
299 llvm::GlobalVariable *GV) const;
301 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
302 GlobalDecl GD, bool ReturnAdjustment) override {
303 // Never dllimport/dllexport thunks.
304 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
307 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
309 if (Linkage == GVA_Internal)
310 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
311 else if (ReturnAdjustment)
312 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
314 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
317 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
318 const ThisAdjustment &TA) override;
320 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
321 const ReturnAdjustment &RA) override;
323 void EmitThreadLocalInitFuncs(
325 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
327 ArrayRef<llvm::Function *> CXXThreadLocalInits,
328 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
330 bool usesThreadWrapperFunction() const override { return false; }
331 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
332 QualType LValType) override;
334 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
335 llvm::GlobalVariable *DeclPtr,
336 bool PerformInit) override;
337 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
338 llvm::Constant *Dtor, llvm::Constant *Addr) override;
340 // ==== Notes on array cookies =========
342 // MSVC seems to only use cookies when the class has a destructor; a
343 // two-argument usual array deallocation function isn't sufficient.
345 // For example, this code prints "100" and "1":
348 // void *operator new[](size_t sz) {
349 // printf("%u\n", sz);
350 // return malloc(sz);
352 // void operator delete[](void *p, size_t sz) {
353 // printf("%u\n", sz);
358 // A *p = new A[100];
361 // Whereas it prints "104" and "104" if you give A a destructor.
363 bool requiresArrayCookie(const CXXDeleteExpr *expr,
364 QualType elementType) override;
365 bool requiresArrayCookie(const CXXNewExpr *expr) override;
366 CharUnits getArrayCookieSizeImpl(QualType type) override;
367 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
369 llvm::Value *NumElements,
370 const CXXNewExpr *expr,
371 QualType ElementType) override;
372 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
373 llvm::Value *allocPtr,
374 CharUnits cookieSize) override;
376 friend struct MSRTTIBuilder;
378 bool isImageRelative() const {
379 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
382 // 5 routines for constructing the llvm types for MS RTTI structs.
383 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
384 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
385 TDTypeName += llvm::utostr(TypeInfoString.size());
386 llvm::StructType *&TypeDescriptorType =
387 TypeDescriptorTypeMap[TypeInfoString.size()];
388 if (TypeDescriptorType)
389 return TypeDescriptorType;
390 llvm::Type *FieldTypes[] = {
393 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
395 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
396 return TypeDescriptorType;
399 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
400 if (!isImageRelative())
405 llvm::StructType *getBaseClassDescriptorType() {
406 if (BaseClassDescriptorType)
407 return BaseClassDescriptorType;
408 llvm::Type *FieldTypes[] = {
409 getImageRelativeType(CGM.Int8PtrTy),
415 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
417 BaseClassDescriptorType = llvm::StructType::create(
418 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
419 return BaseClassDescriptorType;
422 llvm::StructType *getClassHierarchyDescriptorType() {
423 if (ClassHierarchyDescriptorType)
424 return ClassHierarchyDescriptorType;
425 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
426 ClassHierarchyDescriptorType = llvm::StructType::create(
427 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
428 llvm::Type *FieldTypes[] = {
432 getImageRelativeType(
433 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
435 ClassHierarchyDescriptorType->setBody(FieldTypes);
436 return ClassHierarchyDescriptorType;
439 llvm::StructType *getCompleteObjectLocatorType() {
440 if (CompleteObjectLocatorType)
441 return CompleteObjectLocatorType;
442 CompleteObjectLocatorType = llvm::StructType::create(
443 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
444 llvm::Type *FieldTypes[] = {
448 getImageRelativeType(CGM.Int8PtrTy),
449 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
450 getImageRelativeType(CompleteObjectLocatorType),
452 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
453 if (!isImageRelative())
454 FieldTypesRef = FieldTypesRef.drop_back();
455 CompleteObjectLocatorType->setBody(FieldTypesRef);
456 return CompleteObjectLocatorType;
459 llvm::GlobalVariable *getImageBase() {
460 StringRef Name = "__ImageBase";
461 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
464 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
466 llvm::GlobalValue::ExternalLinkage,
467 /*Initializer=*/nullptr, Name);
470 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
471 if (!isImageRelative())
474 if (PtrVal->isNullValue())
475 return llvm::Constant::getNullValue(CGM.IntTy);
477 llvm::Constant *ImageBaseAsInt =
478 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
479 llvm::Constant *PtrValAsInt =
480 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
481 llvm::Constant *Diff =
482 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
483 /*HasNUW=*/true, /*HasNSW=*/true);
484 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
488 MicrosoftMangleContext &getMangleContext() {
489 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
492 llvm::Constant *getZeroInt() {
493 return llvm::ConstantInt::get(CGM.IntTy, 0);
496 llvm::Constant *getAllOnesInt() {
497 return llvm::Constant::getAllOnesValue(CGM.IntTy);
500 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
501 return C ? C : getZeroInt();
504 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
505 return C ? C : getZeroInt();
508 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
511 GetNullMemberPointerFields(const MemberPointerType *MPT,
512 llvm::SmallVectorImpl<llvm::Constant *> &fields);
514 /// \brief Shared code for virtual base adjustment. Returns the offset from
515 /// the vbptr to the virtual base. Optionally returns the address of the
517 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
519 llvm::Value *VBPtrOffset,
520 llvm::Value *VBTableOffset,
521 llvm::Value **VBPtr = nullptr);
523 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
526 int32_t VBTableOffset,
527 llvm::Value **VBPtr = nullptr) {
528 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
529 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
530 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
531 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
534 std::pair<llvm::Value *, llvm::Value *>
535 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
536 QualType SrcRecordTy);
538 /// \brief Performs a full virtual base adjustment. Used to dereference
539 /// pointers to members of virtual bases.
540 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
541 const CXXRecordDecl *RD, llvm::Value *Base,
542 llvm::Value *VirtualBaseAdjustmentOffset,
543 llvm::Value *VBPtrOffset /* optional */);
545 /// \brief Emits a full member pointer with the fields common to data and
546 /// function member pointers.
547 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
548 bool IsMemberFunction,
549 const CXXRecordDecl *RD,
550 CharUnits NonVirtualBaseAdjustment,
551 unsigned VBTableIndex);
553 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
556 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
557 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
559 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
560 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
562 /// \brief Generate a thunk for calling a virtual member function MD.
563 llvm::Function *EmitVirtualMemPtrThunk(
564 const CXXMethodDecl *MD,
565 const MicrosoftVTableContext::MethodVFTableLocation &ML);
568 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
570 bool isZeroInitializable(const MemberPointerType *MPT) override;
572 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
573 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
574 return RD->hasAttr<MSInheritanceAttr>();
577 bool isTypeInfoCalculable(QualType Ty) const override {
578 if (!CGCXXABI::isTypeInfoCalculable(Ty))
580 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
581 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
582 if (!RD->hasAttr<MSInheritanceAttr>())
588 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
590 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
591 CharUnits offset) override;
592 llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override;
593 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
595 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
598 const MemberPointerType *MPT,
599 bool Inequality) override;
601 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
603 const MemberPointerType *MPT) override;
606 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
607 llvm::Value *Base, llvm::Value *MemPtr,
608 const MemberPointerType *MPT) override;
610 llvm::Value *EmitNonNullMemberPointerConversion(
611 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
612 CastKind CK, CastExpr::path_const_iterator PathBegin,
613 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
614 CGBuilderTy &Builder);
616 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
618 llvm::Value *Src) override;
620 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
621 llvm::Constant *Src) override;
623 llvm::Constant *EmitMemberPointerConversion(
624 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
625 CastKind CK, CastExpr::path_const_iterator PathBegin,
626 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
629 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
630 llvm::Value *&This, llvm::Value *MemPtr,
631 const MemberPointerType *MPT) override;
633 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
635 llvm::StructType *getCatchHandlerTypeType() {
636 if (!CatchHandlerTypeType) {
637 llvm::Type *FieldTypes[] = {
639 CGM.Int8PtrTy, // TypeDescriptor
641 CatchHandlerTypeType = llvm::StructType::create(
642 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
644 return CatchHandlerTypeType;
647 llvm::StructType *getCatchableTypeType() {
648 if (CatchableTypeType)
649 return CatchableTypeType;
650 llvm::Type *FieldTypes[] = {
652 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
653 CGM.IntTy, // NonVirtualAdjustment
654 CGM.IntTy, // OffsetToVBPtr
655 CGM.IntTy, // VBTableIndex
657 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
659 CatchableTypeType = llvm::StructType::create(
660 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
661 return CatchableTypeType;
664 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
665 llvm::StructType *&CatchableTypeArrayType =
666 CatchableTypeArrayTypeMap[NumEntries];
667 if (CatchableTypeArrayType)
668 return CatchableTypeArrayType;
670 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
671 CTATypeName += llvm::utostr(NumEntries);
673 getImageRelativeType(getCatchableTypeType()->getPointerTo());
674 llvm::Type *FieldTypes[] = {
675 CGM.IntTy, // NumEntries
676 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
678 CatchableTypeArrayType =
679 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
680 return CatchableTypeArrayType;
683 llvm::StructType *getThrowInfoType() {
685 return ThrowInfoType;
686 llvm::Type *FieldTypes[] = {
688 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
689 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
690 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
692 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
694 return ThrowInfoType;
697 llvm::Constant *getThrowFn() {
698 // _CxxThrowException is passed an exception object and a ThrowInfo object
699 // which describes the exception.
700 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
701 llvm::FunctionType *FTy =
702 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
703 auto *Fn = cast<llvm::Function>(
704 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
705 // _CxxThrowException is stdcall on 32-bit x86 platforms.
706 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
707 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
711 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
714 llvm::Constant *getCatchableType(QualType T,
715 uint32_t NVOffset = 0,
716 int32_t VBPtrOffset = -1,
717 uint32_t VBIndex = 0);
719 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
721 llvm::GlobalVariable *getThrowInfo(QualType T) override;
724 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
725 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
726 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
727 /// \brief All the vftables that have been referenced.
728 VFTablesMapTy VFTablesMap;
729 VTablesMapTy VTablesMap;
731 /// \brief This set holds the record decls we've deferred vtable emission for.
732 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
735 /// \brief All the vbtables which have been referenced.
736 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
738 /// Info on the global variable used to guard initialization of static locals.
739 /// The BitIndex field is only used for externally invisible declarations.
741 GuardInfo() : Guard(nullptr), BitIndex(0) {}
742 llvm::GlobalVariable *Guard;
746 /// Map from DeclContext to the current guard variable. We assume that the
747 /// AST is visited in source code order.
748 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
749 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
750 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
752 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
753 llvm::StructType *BaseClassDescriptorType;
754 llvm::StructType *ClassHierarchyDescriptorType;
755 llvm::StructType *CompleteObjectLocatorType;
757 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
759 llvm::StructType *CatchableTypeType;
760 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
761 llvm::StructType *ThrowInfoType;
762 llvm::StructType *CatchHandlerTypeType;
767 CGCXXABI::RecordArgABI
768 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
769 switch (CGM.getTarget().getTriple().getArch()) {
771 // FIXME: Implement for other architectures.
774 case llvm::Triple::x86:
775 // All record arguments are passed in memory on x86. Decide whether to
776 // construct the object directly in argument memory, or to construct the
777 // argument elsewhere and copy the bytes during the call.
779 // If C++ prohibits us from making a copy, construct the arguments directly
780 // into argument memory.
781 if (!canCopyArgument(RD))
782 return RAA_DirectInMemory;
784 // Otherwise, construct the argument into a temporary and copy the bytes
785 // into the outgoing argument memory.
788 case llvm::Triple::x86_64:
789 // Win64 passes objects with non-trivial copy ctors indirectly.
790 if (RD->hasNonTrivialCopyConstructor())
793 // If an object has a destructor, we'd really like to pass it indirectly
794 // because it allows us to elide copies. Unfortunately, MSVC makes that
795 // impossible for small types, which it will pass in a single register or
796 // stack slot. Most objects with dtors are large-ish, so handle that early.
797 // We can't call out all large objects as being indirect because there are
798 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
799 // how we pass large POD types.
800 if (RD->hasNonTrivialDestructor() &&
801 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
804 // We have a trivial copy constructor or no copy constructors, but we have
805 // to make sure it isn't deleted.
806 bool CopyDeleted = false;
807 for (const CXXConstructorDecl *CD : RD->ctors()) {
808 if (CD->isCopyConstructor()) {
809 assert(CD->isTrivial());
810 // We had at least one undeleted trivial copy ctor. Return directly.
811 if (!CD->isDeleted())
817 // The trivial copy constructor was deleted. Return indirectly.
821 // There were no copy ctors. Return in RAX.
825 llvm_unreachable("invalid enum");
828 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
829 const CXXDeleteExpr *DE,
831 QualType ElementType,
832 const CXXDestructorDecl *Dtor) {
833 // FIXME: Provide a source location here even though there's no
834 // CXXMemberCallExpr for dtor call.
835 bool UseGlobalDelete = DE->isGlobalDelete();
836 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
837 llvm::Value *MDThis =
838 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
840 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
843 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
844 llvm::Value *Args[] = {
845 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
846 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
847 auto *Fn = getThrowFn();
849 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
851 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
855 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
856 CallEndCatchMSVC() {}
857 void Emit(CodeGenFunction &CGF, Flags flags) override {
858 CGF.EmitNounwindRuntimeCall(
859 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
864 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
865 const CXXCatchStmt *S) {
866 // In the MS ABI, the runtime handles the copy, and the catch handler is
867 // responsible for destruction.
868 VarDecl *CatchParam = S->getExceptionDecl();
869 llvm::Value *Exn = CGF.getExceptionFromSlot();
870 llvm::Function *BeginCatch =
871 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
873 // If this is a catch-all or the catch parameter is unnamed, we don't need to
874 // emit an alloca to the object.
875 if (!CatchParam || !CatchParam->getDeclName()) {
876 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
877 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
878 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
882 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
883 llvm::Value *ParamAddr =
884 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
885 llvm::Value *Args[2] = {Exn, ParamAddr};
886 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
887 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
888 CGF.EmitAutoVarCleanups(var);
891 std::pair<llvm::Value *, llvm::Value *>
892 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
893 QualType SrcRecordTy) {
894 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
895 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
896 const ASTContext &Context = getContext();
898 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
899 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
901 // Perform a base adjustment.
902 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
903 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
904 [&](const CXXBaseSpecifier &Base) {
905 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
906 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
908 llvm::Value *Offset = GetVirtualBaseClassOffset(
909 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
910 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
911 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
912 return std::make_pair(Value, Offset);
915 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
916 QualType SrcRecordTy) {
917 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
919 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
922 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
923 llvm::Value *Argument) {
924 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
925 llvm::FunctionType *FTy =
926 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
927 llvm::Value *Args[] = {Argument};
928 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
929 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
932 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
933 llvm::CallSite Call =
934 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
935 Call.setDoesNotReturn();
936 CGF.Builder.CreateUnreachable();
939 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
940 QualType SrcRecordTy,
941 llvm::Value *ThisPtr,
942 llvm::Type *StdTypeInfoPtrTy) {
944 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
945 return CGF.Builder.CreateBitCast(
946 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
949 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
950 QualType SrcRecordTy) {
951 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
953 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
956 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
957 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
958 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
959 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
961 llvm::Value *SrcRTTI =
962 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
963 llvm::Value *DestRTTI =
964 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
967 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
969 // PVOID __RTDynamicCast(
975 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
976 CGF.Int8PtrTy, CGF.Int32Ty};
977 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
978 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
980 llvm::Value *Args[] = {
981 Value, Offset, SrcRTTI, DestRTTI,
982 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
983 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
984 return CGF.Builder.CreateBitCast(Value, DestLTy);
988 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
989 QualType SrcRecordTy,
992 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
994 // PVOID __RTCastToVoid(
996 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
997 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
998 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
1000 llvm::Value *Args[] = {Value};
1001 return CGF.EmitRuntimeCall(Function, Args);
1004 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
1008 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
1009 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
1010 const CXXRecordDecl *BaseClassDecl) {
1011 const ASTContext &Context = getContext();
1012 int64_t VBPtrChars =
1013 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
1014 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
1015 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
1016 CharUnits VBTableChars =
1018 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
1019 llvm::Value *VBTableOffset =
1020 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
1022 llvm::Value *VBPtrToNewBase =
1023 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
1025 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
1026 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
1029 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
1030 return isa<CXXConstructorDecl>(GD.getDecl());
1033 static bool isDeletingDtor(GlobalDecl GD) {
1034 return isa<CXXDestructorDecl>(GD.getDecl()) &&
1035 GD.getDtorType() == Dtor_Deleting;
1038 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
1039 return isDeletingDtor(GD);
1042 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
1043 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
1047 if (FI.isInstanceMethod()) {
1048 // If it's an instance method, aggregates are always returned indirectly via
1049 // the second parameter.
1050 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1051 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
1053 } else if (!RD->isPOD()) {
1054 // If it's a free function, non-POD types are returned indirectly.
1055 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1059 // Otherwise, use the C ABI rules.
1064 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1065 const CXXRecordDecl *RD) {
1066 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1067 assert(IsMostDerivedClass &&
1068 "ctor for a class with virtual bases must have an implicit parameter");
1069 llvm::Value *IsCompleteObject =
1070 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1072 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1073 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1074 CGF.Builder.CreateCondBr(IsCompleteObject,
1075 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1077 CGF.EmitBlock(CallVbaseCtorsBB);
1079 // Fill in the vbtable pointers here.
1080 EmitVBPtrStores(CGF, RD);
1082 // CGF will put the base ctor calls in this basic block for us later.
1084 return SkipVbaseCtorsBB;
1087 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1088 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1089 // In most cases, an override for a vbase virtual method can adjust
1090 // the "this" parameter by applying a constant offset.
1091 // However, this is not enough while a constructor or a destructor of some
1092 // class X is being executed if all the following conditions are met:
1093 // - X has virtual bases, (1)
1094 // - X overrides a virtual method M of a vbase Y, (2)
1095 // - X itself is a vbase of the most derived class.
1097 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1098 // which holds the extra amount of "this" adjustment we must do when we use
1099 // the X vftables (i.e. during X ctor or dtor).
1100 // Outside the ctors and dtors, the values of vtorDisps are zero.
1102 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1103 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1104 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1105 CGBuilderTy &Builder = CGF.Builder;
1108 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1109 llvm::Value *Int8This = nullptr; // Initialize lazily.
1111 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1113 if (!I->second.hasVtorDisp())
1116 llvm::Value *VBaseOffset =
1117 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1118 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1119 // just to Trunc back immediately.
1120 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1121 uint64_t ConstantVBaseOffset =
1122 Layout.getVBaseClassOffset(I->first).getQuantity();
1124 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1125 llvm::Value *VtorDispValue = Builder.CreateSub(
1126 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1130 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1131 CGF.Int8Ty->getPointerTo(AS));
1132 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1133 // vtorDisp is always the 32-bits before the vbase in the class layout.
1134 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1135 VtorDispPtr = Builder.CreateBitCast(
1136 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1138 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1142 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1143 const CXXMethodDecl *MD) {
1144 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1145 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1146 CallingConv ActualCallingConv =
1147 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1148 return ExpectedCallingConv == ActualCallingConv;
1151 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1152 // There's only one constructor type in this ABI.
1153 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1155 // Exported default constructors either have a simple call-site where they use
1156 // the typical calling convention and have a single 'this' pointer for an
1157 // argument -or- they get a wrapper function which appropriately thunks to the
1158 // real default constructor. This thunk is the default constructor closure.
1159 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1160 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1161 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1162 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1163 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1167 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1168 const CXXRecordDecl *RD) {
1169 llvm::Value *ThisInt8Ptr =
1170 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1171 const ASTContext &Context = getContext();
1172 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1174 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1175 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1176 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1177 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1178 const ASTRecordLayout &SubobjectLayout =
1179 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1180 CharUnits Offs = VBT->NonVirtualOffset;
1181 Offs += SubobjectLayout.getVBPtrOffset();
1182 if (VBT->getVBaseWithVPtr())
1183 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1184 llvm::Value *VBPtr =
1185 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1186 llvm::Value *GVPtr =
1187 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1188 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1189 "vbptr." + VBT->ReusingBase->getName());
1190 CGF.Builder.CreateStore(GVPtr, VBPtr);
1195 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1196 SmallVectorImpl<CanQualType> &ArgTys) {
1197 // TODO: 'for base' flag
1198 if (T == StructorType::Deleting) {
1199 // The scalar deleting destructor takes an implicit int parameter.
1200 ArgTys.push_back(getContext().IntTy);
1202 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1206 // All parameters are already in place except is_most_derived, which goes
1207 // after 'this' if it's variadic and last if it's not.
1209 const CXXRecordDecl *Class = CD->getParent();
1210 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1211 if (Class->getNumVBases()) {
1212 if (FPT->isVariadic())
1213 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1215 ArgTys.push_back(getContext().IntTy);
1219 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1220 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1221 // other destructor variants are delegating thunks.
1222 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1226 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1227 GD = GD.getCanonicalDecl();
1228 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1230 GlobalDecl LookupGD = GD;
1231 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1232 // Complete destructors take a pointer to the complete object as a
1233 // parameter, thus don't need this adjustment.
1234 if (GD.getDtorType() == Dtor_Complete)
1237 // There's no Dtor_Base in vftable but it shares the this adjustment with
1238 // the deleting one, so look it up instead.
1239 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1242 MicrosoftVTableContext::MethodVFTableLocation ML =
1243 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1244 CharUnits Adjustment = ML.VFPtrOffset;
1246 // Normal virtual instance methods need to adjust from the vfptr that first
1247 // defined the virtual method to the virtual base subobject, but destructors
1248 // do not. The vector deleting destructor thunk applies this adjustment for
1250 if (isa<CXXDestructorDecl>(MD))
1251 Adjustment = CharUnits::Zero();
1254 const ASTRecordLayout &DerivedLayout =
1255 getContext().getASTRecordLayout(MD->getParent());
1256 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1262 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1263 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1265 // If the call of a virtual function is not virtual, we just have to
1266 // compensate for the adjustment the virtual function does in its prologue.
1267 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1268 if (Adjustment.isZero())
1271 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1272 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1273 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1274 assert(Adjustment.isPositive());
1275 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1278 GD = GD.getCanonicalDecl();
1279 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1281 GlobalDecl LookupGD = GD;
1282 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1283 // Complete dtors take a pointer to the complete object,
1284 // thus don't need adjustment.
1285 if (GD.getDtorType() == Dtor_Complete)
1288 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1289 // with the base one, so look up the deleting one instead.
1290 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1292 MicrosoftVTableContext::MethodVFTableLocation ML =
1293 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1295 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1296 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1297 CharUnits StaticOffset = ML.VFPtrOffset;
1299 // Base destructors expect 'this' to point to the beginning of the base
1300 // subobject, not the first vfptr that happens to contain the virtual dtor.
1301 // However, we still need to apply the virtual base adjustment.
1302 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1303 StaticOffset = CharUnits::Zero();
1306 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1307 llvm::Value *VBaseOffset =
1308 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1309 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1311 if (!StaticOffset.isZero()) {
1312 assert(StaticOffset.isPositive());
1313 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1315 // Non-virtual adjustment might result in a pointer outside the allocated
1316 // object, e.g. if the final overrider class is laid out after the virtual
1317 // base that declares a method in the most derived class.
1318 // FIXME: Update the code that emits this adjustment in thunks prologues.
1319 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1321 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1322 StaticOffset.getQuantity());
1328 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1330 FunctionArgList &Params) {
1331 ASTContext &Context = getContext();
1332 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1333 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1334 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1335 ImplicitParamDecl *IsMostDerived
1336 = ImplicitParamDecl::Create(Context, nullptr,
1337 CGF.CurGD.getDecl()->getLocation(),
1338 &Context.Idents.get("is_most_derived"),
1340 // The 'most_derived' parameter goes second if the ctor is variadic and last
1341 // if it's not. Dtors can't be variadic.
1342 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1343 if (FPT->isVariadic())
1344 Params.insert(Params.begin() + 1, IsMostDerived);
1346 Params.push_back(IsMostDerived);
1347 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1348 } else if (isDeletingDtor(CGF.CurGD)) {
1349 ImplicitParamDecl *ShouldDelete
1350 = ImplicitParamDecl::Create(Context, nullptr,
1351 CGF.CurGD.getDecl()->getLocation(),
1352 &Context.Idents.get("should_call_delete"),
1354 Params.push_back(ShouldDelete);
1355 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1359 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1360 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1361 // In this ABI, every virtual function takes a pointer to one of the
1362 // subobjects that first defines it as the 'this' parameter, rather than a
1363 // pointer to the final overrider subobject. Thus, we need to adjust it back
1364 // to the final overrider subobject before use.
1365 // See comments in the MicrosoftVFTableContext implementation for the details.
1366 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1367 if (Adjustment.isZero())
1370 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1371 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1372 *thisTy = This->getType();
1374 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1375 assert(Adjustment.isPositive());
1376 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1377 -Adjustment.getQuantity());
1378 return CGF.Builder.CreateBitCast(This, thisTy);
1381 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1384 /// If this is a function that the ABI specifies returns 'this', initialize
1385 /// the return slot to 'this' at the start of the function.
1387 /// Unlike the setting of return types, this is done within the ABI
1388 /// implementation instead of by clients of CGCXXABI because:
1389 /// 1) getThisValue is currently protected
1390 /// 2) in theory, an ABI could implement 'this' returns some other way;
1391 /// HasThisReturn only specifies a contract, not the implementation
1392 if (HasThisReturn(CGF.CurGD))
1393 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1394 else if (hasMostDerivedReturn(CGF.CurGD))
1395 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1398 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1399 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1400 assert(getStructorImplicitParamDecl(CGF) &&
1401 "no implicit parameter for a constructor with virtual bases?");
1402 getStructorImplicitParamValue(CGF)
1403 = CGF.Builder.CreateLoad(
1404 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1408 if (isDeletingDtor(CGF.CurGD)) {
1409 assert(getStructorImplicitParamDecl(CGF) &&
1410 "no implicit parameter for a deleting destructor?");
1411 getStructorImplicitParamValue(CGF)
1412 = CGF.Builder.CreateLoad(
1413 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1414 "should_call_delete");
1418 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1419 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1420 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1421 assert(Type == Ctor_Complete || Type == Ctor_Base);
1423 // Check if we need a 'most_derived' parameter.
1424 if (!D->getParent()->getNumVBases())
1427 // Add the 'most_derived' argument second if we are variadic or last if not.
1428 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1429 llvm::Value *MostDerivedArg =
1430 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1431 RValue RV = RValue::get(MostDerivedArg);
1432 if (MostDerivedArg) {
1433 if (FPT->isVariadic())
1434 Args.insert(Args.begin() + 1,
1435 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1437 Args.add(RV, getContext().IntTy);
1440 return 1; // Added one arg.
1443 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1444 const CXXDestructorDecl *DD,
1445 CXXDtorType Type, bool ForVirtualBase,
1446 bool Delegating, llvm::Value *This) {
1447 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1449 if (DD->isVirtual()) {
1450 assert(Type != CXXDtorType::Dtor_Deleting &&
1451 "The deleting destructor should only be called via a virtual call");
1452 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1456 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1457 /*ImplicitParam=*/nullptr,
1458 /*ImplicitParamTy=*/QualType(), nullptr,
1459 getFromDtorType(Type));
1462 void MicrosoftCXXABI::emitVTableBitSetEntries(VPtrInfo *Info,
1463 const CXXRecordDecl *RD,
1464 llvm::GlobalVariable *VTable) {
1465 if (!getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIVCall) &&
1466 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFINVCall) &&
1467 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIDerivedCast) &&
1468 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIUnrelatedCast))
1471 llvm::NamedMDNode *BitsetsMD =
1472 CGM.getModule().getOrInsertNamedMetadata("llvm.bitsets");
1474 // The location of the first virtual function pointer in the virtual table,
1475 // aka the "address point" on Itanium. This is at offset 0 if RTTI is
1476 // disabled, or sizeof(void*) if RTTI is enabled.
1477 CharUnits AddressPoint =
1478 getContext().getLangOpts().RTTIData
1479 ? getContext().toCharUnitsFromBits(
1480 getContext().getTargetInfo().getPointerWidth(0))
1481 : CharUnits::Zero();
1483 if (Info->PathToBaseWithVPtr.empty()) {
1484 if (!CGM.IsCFIBlacklistedRecord(RD))
1485 BitsetsMD->addOperand(
1486 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1490 // Add a bitset entry for the least derived base belonging to this vftable.
1491 if (!CGM.IsCFIBlacklistedRecord(Info->PathToBaseWithVPtr.back()))
1492 BitsetsMD->addOperand(CGM.CreateVTableBitSetEntry(
1493 VTable, AddressPoint, Info->PathToBaseWithVPtr.back()));
1495 // Add a bitset entry for each derived class that is laid out at the same
1496 // offset as the least derived base.
1497 for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) {
1498 const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1];
1499 const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I];
1501 const ASTRecordLayout &Layout =
1502 getContext().getASTRecordLayout(DerivedRD);
1504 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1505 if (VBI == Layout.getVBaseOffsetsMap().end())
1506 Offset = Layout.getBaseClassOffset(BaseRD);
1508 Offset = VBI->second.VBaseOffset;
1509 if (!Offset.isZero())
1511 if (!CGM.IsCFIBlacklistedRecord(DerivedRD))
1512 BitsetsMD->addOperand(
1513 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, DerivedRD));
1516 // Finally do the same for the most derived class.
1517 if (Info->FullOffsetInMDC.isZero() && !CGM.IsCFIBlacklistedRecord(RD))
1518 BitsetsMD->addOperand(
1519 CGM.CreateVTableBitSetEntry(VTable, AddressPoint, RD));
1522 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1523 const CXXRecordDecl *RD) {
1524 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1525 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1527 for (VPtrInfo *Info : VFPtrs) {
1528 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1529 if (VTable->hasInitializer())
1532 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1533 ? getMSCompleteObjectLocator(RD, Info)
1536 const VTableLayout &VTLayout =
1537 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1538 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1539 RD, VTLayout.vtable_component_begin(),
1540 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1541 VTLayout.getNumVTableThunks(), RTTI);
1543 VTable->setInitializer(Init);
1545 emitVTableBitSetEntries(Info, RD, VTable);
1549 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1550 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1551 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1552 NeedsVirtualOffset = (NearestVBase != nullptr);
1554 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1555 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1556 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1557 if (!VTableAddressPoint) {
1558 assert(Base.getBase()->getNumVBases() &&
1559 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1561 return VTableAddressPoint;
1564 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1565 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1566 SmallString<256> &Name) {
1567 llvm::raw_svector_ostream Out(Name);
1568 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1571 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1572 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1573 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1574 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1575 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1576 assert(VFTable && "Couldn't find a vftable for the given base?");
1580 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1581 CharUnits VPtrOffset) {
1582 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1583 // shouldn't be used in the given record type. We want to cache this result in
1584 // VFTablesMap, thus a simple zero check is not sufficient.
1585 VFTableIdTy ID(RD, VPtrOffset);
1586 VTablesMapTy::iterator I;
1588 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1592 llvm::GlobalVariable *&VTable = I->second;
1594 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1595 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1597 if (DeferredVFTables.insert(RD).second) {
1598 // We haven't processed this record type before.
1599 // Queue up this v-table for possible deferred emission.
1600 CGM.addDeferredVTable(RD);
1603 // Create all the vftables at once in order to make sure each vftable has
1604 // a unique mangled name.
1605 llvm::StringSet<> ObservedMangledNames;
1606 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1607 SmallString<256> Name;
1608 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1609 if (!ObservedMangledNames.insert(Name.str()).second)
1610 llvm_unreachable("Already saw this mangling before?");
1615 VPtrInfo *const *VFPtrI =
1616 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1617 return VPI->FullOffsetInMDC == VPtrOffset;
1619 if (VFPtrI == VFPtrs.end()) {
1620 VFTablesMap[ID] = nullptr;
1623 VPtrInfo *VFPtr = *VFPtrI;
1625 SmallString<256> VFTableName;
1626 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1628 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1629 bool VFTableComesFromAnotherTU =
1630 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1631 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1632 bool VTableAliasIsRequred =
1633 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1635 if (llvm::GlobalValue *VFTable =
1636 CGM.getModule().getNamedGlobal(VFTableName)) {
1637 VFTablesMap[ID] = VFTable;
1638 return VTableAliasIsRequred
1639 ? cast<llvm::GlobalVariable>(
1640 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1641 : cast<llvm::GlobalVariable>(VFTable);
1644 uint64_t NumVTableSlots =
1645 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1646 .getNumVTableComponents();
1647 llvm::GlobalValue::LinkageTypes VTableLinkage =
1648 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1650 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1652 llvm::ArrayType *VTableType =
1653 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1655 // Create a backing variable for the contents of VTable. The VTable may
1656 // or may not include space for a pointer to RTTI data.
1657 llvm::GlobalValue *VFTable;
1658 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1659 /*isConstant=*/true, VTableLinkage,
1660 /*Initializer=*/nullptr, VTableName);
1661 VTable->setUnnamedAddr(true);
1663 llvm::Comdat *C = nullptr;
1664 if (!VFTableComesFromAnotherTU &&
1665 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1666 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1667 VTableAliasIsRequred)))
1668 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1670 // Only insert a pointer into the VFTable for RTTI data if we are not
1671 // importing it. We never reference the RTTI data directly so there is no
1672 // need to make room for it.
1673 if (VTableAliasIsRequred) {
1674 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1675 llvm::ConstantInt::get(CGM.IntTy, 1)};
1676 // Create a GEP which points just after the first entry in the VFTable,
1677 // this should be the location of the first virtual method.
1678 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1679 VTable->getValueType(), VTable, GEPIndices);
1680 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1681 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1683 C->setSelectionKind(llvm::Comdat::Largest);
1685 VFTable = llvm::GlobalAlias::create(
1686 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1687 VFTableName.str(), VTableGEP, &CGM.getModule());
1688 VFTable->setUnnamedAddr(true);
1690 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1691 // be referencing any RTTI data.
1692 // The GlobalVariable will end up being an appropriate definition of the
1697 VTable->setComdat(C);
1699 if (RD->hasAttr<DLLImportAttr>())
1700 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1701 else if (RD->hasAttr<DLLExportAttr>())
1702 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1704 VFTablesMap[ID] = VFTable;
1708 // Compute the identity of the most derived class whose virtual table is located
1709 // at the given offset into RD.
1710 static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx,
1711 const CXXRecordDecl *RD,
1713 if (Offset.isZero())
1716 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
1717 const CXXRecordDecl *MaxBase = nullptr;
1718 CharUnits MaxBaseOffset;
1719 for (auto &&B : RD->bases()) {
1720 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1721 CharUnits BaseOffset = Layout.getBaseClassOffset(Base);
1722 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1724 MaxBaseOffset = BaseOffset;
1727 for (auto &&B : RD->vbases()) {
1728 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1729 CharUnits BaseOffset = Layout.getVBaseClassOffset(Base);
1730 if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) {
1732 MaxBaseOffset = BaseOffset;
1736 return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset);
1739 // Compute the identity of the most derived class whose virtual table is located
1740 // at the MethodVFTableLocation ML.
1741 static const CXXRecordDecl *
1742 getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD,
1743 MicrosoftVTableContext::MethodVFTableLocation &ML) {
1744 const CXXRecordDecl *RD = ML.VBase;
1746 RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
1748 return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset);
1751 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1755 SourceLocation Loc) {
1756 GD = GD.getCanonicalDecl();
1757 CGBuilderTy &Builder = CGF.Builder;
1759 Ty = Ty->getPointerTo()->getPointerTo();
1761 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1762 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1764 MicrosoftVTableContext::MethodVFTableLocation ML =
1765 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1766 if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
1767 CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML),
1768 VTable, CodeGenFunction::CFITCK_VCall, Loc);
1770 llvm::Value *VFuncPtr =
1771 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1772 return Builder.CreateLoad(VFuncPtr);
1775 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1776 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1777 llvm::Value *This, const CXXMemberCallExpr *CE) {
1778 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1779 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1781 // We have only one destructor in the vftable but can get both behaviors
1782 // by passing an implicit int parameter.
1783 GlobalDecl GD(Dtor, Dtor_Deleting);
1784 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1785 Dtor, StructorType::Deleting);
1786 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1787 llvm::Value *Callee = getVirtualFunctionPointer(
1788 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1790 ASTContext &Context = getContext();
1791 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1792 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1793 DtorType == Dtor_Deleting);
1795 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1796 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1797 ImplicitParam, Context.IntTy, CE,
1798 StructorType::Deleting);
1799 return RV.getScalarVal();
1802 const VBTableGlobals &
1803 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1804 // At this layer, we can key the cache off of a single class, which is much
1805 // easier than caching each vbtable individually.
1806 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1808 std::tie(Entry, Added) =
1809 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1810 VBTableGlobals &VBGlobals = Entry->second;
1814 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1815 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1817 // Cache the globals for all vbtables so we don't have to recompute the
1819 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1820 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1821 E = VBGlobals.VBTables->end();
1823 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1829 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1830 const CXXMethodDecl *MD,
1831 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1832 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1833 "can't form pointers to ctors or virtual dtors");
1835 // Calculate the mangled name.
1836 SmallString<256> ThunkName;
1837 llvm::raw_svector_ostream Out(ThunkName);
1838 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1841 // If the thunk has been generated previously, just return it.
1842 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1843 return cast<llvm::Function>(GV);
1845 // Create the llvm::Function.
1846 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1847 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1848 llvm::Function *ThunkFn =
1849 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1850 ThunkName.str(), &CGM.getModule());
1851 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1853 ThunkFn->setLinkage(MD->isExternallyVisible()
1854 ? llvm::GlobalValue::LinkOnceODRLinkage
1855 : llvm::GlobalValue::InternalLinkage);
1856 if (MD->isExternallyVisible())
1857 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1859 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1860 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1862 // Add the "thunk" attribute so that LLVM knows that the return type is
1863 // meaningless. These thunks can be used to call functions with differing
1864 // return types, and the caller is required to cast the prototype
1865 // appropriately to extract the correct value.
1866 ThunkFn->addFnAttr("thunk");
1868 // These thunks can be compared, so they are not unnamed.
1869 ThunkFn->setUnnamedAddr(false);
1872 CodeGenFunction CGF(CGM);
1873 CGF.CurGD = GlobalDecl(MD);
1874 CGF.CurFuncIsThunk = true;
1876 // Build FunctionArgs, but only include the implicit 'this' parameter
1878 FunctionArgList FunctionArgs;
1879 buildThisParam(CGF, FunctionArgs);
1881 // Start defining the function.
1882 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1883 FunctionArgs, MD->getLocation(), SourceLocation());
1886 // Load the vfptr and then callee from the vftable. The callee should have
1887 // adjusted 'this' so that the vfptr is at offset zero.
1888 llvm::Value *VTable = CGF.GetVTablePtr(
1889 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1890 llvm::Value *VFuncPtr =
1891 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1892 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1894 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1899 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1900 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1901 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1902 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1903 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1904 if (GV->isDeclaration())
1905 emitVBTableDefinition(*VBT, RD, GV);
1909 llvm::GlobalVariable *
1910 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1911 llvm::GlobalVariable::LinkageTypes Linkage) {
1912 SmallString<256> OutName;
1913 llvm::raw_svector_ostream Out(OutName);
1914 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1916 StringRef Name = OutName.str();
1918 llvm::ArrayType *VBTableType =
1919 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1921 assert(!CGM.getModule().getNamedGlobal(Name) &&
1922 "vbtable with this name already exists: mangling bug?");
1923 llvm::GlobalVariable *GV =
1924 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1925 GV->setUnnamedAddr(true);
1927 if (RD->hasAttr<DLLImportAttr>())
1928 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1929 else if (RD->hasAttr<DLLExportAttr>())
1930 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1932 if (!GV->hasExternalLinkage())
1933 emitVBTableDefinition(VBT, RD, GV);
1938 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1939 const CXXRecordDecl *RD,
1940 llvm::GlobalVariable *GV) const {
1941 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1943 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1944 "should only emit vbtables for classes with vbtables");
1946 const ASTRecordLayout &BaseLayout =
1947 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1948 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1950 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1953 // The offset from ReusingBase's vbptr to itself always leads.
1954 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1955 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1957 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1958 for (const auto &I : ReusingBase->vbases()) {
1959 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1960 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1961 assert(!Offset.isNegative());
1963 // Make it relative to the subobject vbptr.
1964 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1965 if (VBT.getVBaseWithVPtr())
1966 CompleteVBPtrOffset +=
1967 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1968 Offset -= CompleteVBPtrOffset;
1970 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1971 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1972 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1975 assert(Offsets.size() ==
1976 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1977 ->getElementType())->getNumElements());
1978 llvm::ArrayType *VBTableType =
1979 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1980 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1981 GV->setInitializer(Init);
1984 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1986 const ThisAdjustment &TA) {
1990 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1992 if (!TA.Virtual.isEmpty()) {
1993 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1994 // Adjust the this argument based on the vtordisp value.
1995 llvm::Value *VtorDispPtr =
1996 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1998 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1999 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
2000 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
2002 if (TA.Virtual.Microsoft.VBPtrOffset) {
2003 // If the final overrider is defined in a virtual base other than the one
2004 // that holds the vfptr, we have to use a vtordispex thunk which looks up
2005 // the vbtable of the derived class.
2006 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
2007 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
2009 llvm::Value *VBaseOffset =
2010 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
2011 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
2012 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2016 if (TA.NonVirtual) {
2017 // Non-virtual adjustment might result in a pointer outside the allocated
2018 // object, e.g. if the final overrider class is laid out after the virtual
2019 // base that declares a method in the most derived class.
2020 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
2023 // Don't need to bitcast back, the call CodeGen will handle this.
2028 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
2029 const ReturnAdjustment &RA) {
2033 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
2035 if (RA.Virtual.Microsoft.VBIndex) {
2036 assert(RA.Virtual.Microsoft.VBIndex > 0);
2037 const ASTContext &Context = getContext();
2038 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
2040 llvm::Value *VBaseOffset =
2041 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
2042 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
2043 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2047 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
2049 // Cast back to the original type.
2050 return CGF.Builder.CreateBitCast(V, Ret->getType());
2053 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
2054 QualType elementType) {
2055 // Microsoft seems to completely ignore the possibility of a
2056 // two-argument usual deallocation function.
2057 return elementType.isDestructedType();
2060 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
2061 // Microsoft seems to completely ignore the possibility of a
2062 // two-argument usual deallocation function.
2063 return expr->getAllocatedType().isDestructedType();
2066 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2067 // The array cookie is always a size_t; we then pad that out to the
2068 // alignment of the element type.
2069 ASTContext &Ctx = getContext();
2070 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2071 Ctx.getTypeAlignInChars(type));
2074 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2075 llvm::Value *allocPtr,
2076 CharUnits cookieSize) {
2077 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
2078 llvm::Value *numElementsPtr =
2079 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
2080 return CGF.Builder.CreateLoad(numElementsPtr);
2083 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2084 llvm::Value *newPtr,
2085 llvm::Value *numElements,
2086 const CXXNewExpr *expr,
2087 QualType elementType) {
2088 assert(requiresArrayCookie(expr));
2090 // The size of the cookie.
2091 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2093 // Compute an offset to the cookie.
2094 llvm::Value *cookiePtr = newPtr;
2096 // Write the number of elements into the appropriate slot.
2097 unsigned AS = newPtr->getType()->getPointerAddressSpace();
2098 llvm::Value *numElementsPtr
2099 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
2100 CGF.Builder.CreateStore(numElements, numElementsPtr);
2102 // Finally, compute a pointer to the actual data buffer by skipping
2103 // over the cookie completely.
2104 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
2105 cookieSize.getQuantity());
2108 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2109 llvm::Constant *Dtor,
2110 llvm::Constant *Addr) {
2111 // Create a function which calls the destructor.
2112 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2114 // extern "C" int __tlregdtor(void (*f)(void));
2115 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2116 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2118 llvm::Constant *TLRegDtor =
2119 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
2120 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2121 TLRegDtorFn->setDoesNotThrow();
2123 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2126 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2127 llvm::Constant *Dtor,
2128 llvm::Constant *Addr) {
2130 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2132 // The default behavior is to use atexit.
2133 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2136 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2138 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
2140 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2141 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
2142 // This will create a GV in the .CRT$XDU section. It will point to our
2143 // initialization function. The CRT will call all of these function
2144 // pointers at start-up time and, eventually, at thread-creation time.
2145 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2146 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2147 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2148 llvm::GlobalVariable::InternalLinkage, InitFunc,
2149 Twine(InitFunc->getName(), "$initializer$"));
2150 InitFuncPtr->setSection(".CRT$XDU");
2151 // This variable has discardable linkage, we have to add it to @llvm.used to
2152 // ensure it won't get discarded.
2153 CGM.addUsedGlobal(InitFuncPtr);
2157 std::vector<llvm::Function *> NonComdatInits;
2158 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2159 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
2160 llvm::Function *F = CXXThreadLocalInits[I];
2162 // If the GV is already in a comdat group, then we have to join it.
2163 if (llvm::Comdat *C = GV->getComdat())
2164 AddToXDU(F)->setComdat(C);
2166 NonComdatInits.push_back(F);
2169 if (!NonComdatInits.empty()) {
2170 llvm::FunctionType *FTy =
2171 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2172 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2173 FTy, "__tls_init", SourceLocation(),
2175 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2181 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2183 QualType LValType) {
2184 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2188 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2189 StringRef VarName("_Init_thread_epoch");
2190 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2192 auto *GV = new llvm::GlobalVariable(
2193 CGM.getModule(), CGM.IntTy,
2194 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2195 /*Initializer=*/nullptr, VarName,
2196 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2197 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2201 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2202 llvm::FunctionType *FTy =
2203 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2204 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2205 return CGM.CreateRuntimeFunction(
2206 FTy, "_Init_thread_header",
2207 llvm::AttributeSet::get(CGM.getLLVMContext(),
2208 llvm::AttributeSet::FunctionIndex,
2209 llvm::Attribute::NoUnwind));
2212 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2213 llvm::FunctionType *FTy =
2214 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2215 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2216 return CGM.CreateRuntimeFunction(
2217 FTy, "_Init_thread_footer",
2218 llvm::AttributeSet::get(CGM.getLLVMContext(),
2219 llvm::AttributeSet::FunctionIndex,
2220 llvm::Attribute::NoUnwind));
2223 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2224 llvm::FunctionType *FTy =
2225 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2226 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2227 return CGM.CreateRuntimeFunction(
2228 FTy, "_Init_thread_abort",
2229 llvm::AttributeSet::get(CGM.getLLVMContext(),
2230 llvm::AttributeSet::FunctionIndex,
2231 llvm::Attribute::NoUnwind));
2235 struct ResetGuardBit : EHScopeStack::Cleanup {
2236 llvm::GlobalVariable *Guard;
2238 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2239 : Guard(Guard), GuardNum(GuardNum) {}
2241 void Emit(CodeGenFunction &CGF, Flags flags) override {
2242 // Reset the bit in the mask so that the static variable may be
2244 CGBuilderTy &Builder = CGF.Builder;
2245 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2246 llvm::ConstantInt *Mask =
2247 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2248 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2252 struct CallInitThreadAbort : EHScopeStack::Cleanup {
2253 llvm::GlobalVariable *Guard;
2254 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2256 void Emit(CodeGenFunction &CGF, Flags flags) override {
2257 // Calling _Init_thread_abort will reset the guard's state.
2258 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2263 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2264 llvm::GlobalVariable *GV,
2266 // MSVC only uses guards for static locals.
2267 if (!D.isStaticLocal()) {
2268 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2269 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2270 llvm::Function *F = CGF.CurFn;
2271 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2272 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2273 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2277 bool ThreadlocalStatic = D.getTLSKind();
2278 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2280 // Thread-safe static variables which aren't thread-specific have a
2281 // per-variable guard.
2282 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2284 CGBuilderTy &Builder = CGF.Builder;
2285 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2286 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2288 // Get the guard variable for this function if we have one already.
2289 GuardInfo *GI = nullptr;
2290 if (ThreadlocalStatic)
2291 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2292 else if (!ThreadsafeStatic)
2293 GI = &GuardVariableMap[D.getDeclContext()];
2295 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2297 if (D.isExternallyVisible()) {
2298 // Externally visible variables have to be numbered in Sema to properly
2299 // handle unreachable VarDecls.
2300 GuardNum = getContext().getStaticLocalNumber(&D);
2301 assert(GuardNum > 0);
2303 } else if (HasPerVariableGuard) {
2304 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2306 // Non-externally visible variables are numbered here in CodeGen.
2307 GuardNum = GI->BitIndex++;
2310 if (!HasPerVariableGuard && GuardNum >= 32) {
2311 if (D.isExternallyVisible())
2312 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2318 // Mangle the name for the guard.
2319 SmallString<256> GuardName;
2321 llvm::raw_svector_ostream Out(GuardName);
2322 if (HasPerVariableGuard)
2323 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2326 getMangleContext().mangleStaticGuardVariable(&D, Out);
2330 // Create the guard variable with a zero-initializer. Just absorb linkage,
2331 // visibility and dll storage class from the guarded variable.
2333 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2334 GV->getLinkage(), Zero, GuardName.str());
2335 GuardVar->setVisibility(GV->getVisibility());
2336 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2337 if (GuardVar->isWeakForLinker())
2338 GuardVar->setComdat(
2339 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2341 GuardVar->setThreadLocal(true);
2342 if (GI && !HasPerVariableGuard)
2343 GI->Guard = GuardVar;
2346 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2347 "static local from the same function had different linkage");
2349 if (!HasPerVariableGuard) {
2350 // Pseudo code for the test:
2351 // if (!(GuardVar & MyGuardBit)) {
2352 // GuardVar |= MyGuardBit;
2353 // ... initialize the object ...;
2356 // Test our bit from the guard variable.
2357 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2358 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2359 llvm::Value *IsInitialized =
2360 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2361 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2362 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2363 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2365 // Set our bit in the guard variable and emit the initializer and add a global
2366 // destructor if appropriate.
2367 CGF.EmitBlock(InitBlock);
2368 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2369 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2370 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2371 CGF.PopCleanupBlock();
2372 Builder.CreateBr(EndBlock);
2375 CGF.EmitBlock(EndBlock);
2377 // Pseudo code for the test:
2378 // if (TSS > _Init_thread_epoch) {
2379 // _Init_thread_header(&TSS);
2381 // ... initialize the object ...;
2382 // _Init_thread_footer(&TSS);
2386 // The algorithm is almost identical to what can be found in the appendix
2389 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2391 // This BasicBLock determines whether or not we have any work to do.
2392 llvm::LoadInst *FirstGuardLoad =
2393 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2394 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2395 llvm::LoadInst *InitThreadEpoch =
2396 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2397 llvm::Value *IsUninitialized =
2398 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2399 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2400 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2401 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2403 // This BasicBlock attempts to determine whether or not this thread is
2404 // responsible for doing the initialization.
2405 CGF.EmitBlock(AttemptInitBlock);
2406 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2407 llvm::LoadInst *SecondGuardLoad =
2408 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2409 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2410 llvm::Value *ShouldDoInit =
2411 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2412 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2413 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2415 // Ok, we ended up getting selected as the initializing thread.
2416 CGF.EmitBlock(InitBlock);
2417 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2418 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2419 CGF.PopCleanupBlock();
2420 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2421 Builder.CreateBr(EndBlock);
2423 CGF.EmitBlock(EndBlock);
2427 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2428 // Null-ness for function memptrs only depends on the first field, which is
2429 // the function pointer. The rest don't matter, so we can zero initialize.
2430 if (MPT->isMemberFunctionPointer())
2433 // The virtual base adjustment field is always -1 for null, so if we have one
2434 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2435 // valid field offset.
2436 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2437 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2438 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2439 RD->nullFieldOffsetIsZero());
2443 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2444 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2445 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2446 llvm::SmallVector<llvm::Type *, 4> fields;
2447 if (MPT->isMemberFunctionPointer())
2448 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2450 fields.push_back(CGM.IntTy); // FieldOffset
2452 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2454 fields.push_back(CGM.IntTy);
2455 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2456 fields.push_back(CGM.IntTy);
2457 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2458 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2460 if (fields.size() == 1)
2462 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2465 void MicrosoftCXXABI::
2466 GetNullMemberPointerFields(const MemberPointerType *MPT,
2467 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2468 assert(fields.empty());
2469 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2470 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2471 if (MPT->isMemberFunctionPointer()) {
2472 // FunctionPointerOrVirtualThunk
2473 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2475 if (RD->nullFieldOffsetIsZero())
2476 fields.push_back(getZeroInt()); // FieldOffset
2478 fields.push_back(getAllOnesInt()); // FieldOffset
2481 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2483 fields.push_back(getZeroInt());
2484 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2485 fields.push_back(getZeroInt());
2486 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2487 fields.push_back(getAllOnesInt());
2491 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2492 llvm::SmallVector<llvm::Constant *, 4> fields;
2493 GetNullMemberPointerFields(MPT, fields);
2494 if (fields.size() == 1)
2496 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2497 assert(Res->getType() == ConvertMemberPointerType(MPT));
2502 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2503 bool IsMemberFunction,
2504 const CXXRecordDecl *RD,
2505 CharUnits NonVirtualBaseAdjustment,
2506 unsigned VBTableIndex) {
2507 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2509 // Single inheritance class member pointer are represented as scalars instead
2511 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2514 llvm::SmallVector<llvm::Constant *, 4> fields;
2515 fields.push_back(FirstField);
2517 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2518 fields.push_back(llvm::ConstantInt::get(
2519 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2521 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2522 CharUnits Offs = CharUnits::Zero();
2524 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2525 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2528 // The rest of the fields are adjusted by conversions to a more derived class.
2529 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2530 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2532 return llvm::ConstantStruct::getAnon(fields);
2536 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2538 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2539 if (RD->getMSInheritanceModel() ==
2540 MSInheritanceAttr::Keyword_virtual_inheritance)
2541 offset -= getContext().getOffsetOfBaseWithVBPtr(RD);
2542 llvm::Constant *FirstField =
2543 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2544 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2545 CharUnits::Zero(), /*VBTableIndex=*/0);
2548 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2550 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2551 const ValueDecl *MPD = MP.getMemberPointerDecl();
2553 return EmitNullMemberPointer(DstTy);
2555 ASTContext &Ctx = getContext();
2556 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2559 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2560 C = EmitMemberFunctionPointer(MD);
2562 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2563 C = EmitMemberDataPointer(DstTy, FieldOffset);
2566 if (!MemberPointerPath.empty()) {
2567 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2568 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2569 const MemberPointerType *SrcTy =
2570 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2571 ->castAs<MemberPointerType>();
2573 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2574 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2575 const CXXRecordDecl *PrevRD = SrcRD;
2576 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2577 const CXXRecordDecl *Base = nullptr;
2578 const CXXRecordDecl *Derived = nullptr;
2579 if (DerivedMember) {
2586 for (const CXXBaseSpecifier &BS : Derived->bases())
2587 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2588 Base->getCanonicalDecl())
2589 DerivedToBasePath.push_back(&BS);
2592 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2594 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2595 : CK_BaseToDerivedMemberPointer;
2596 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2597 DerivedToBasePath.end(), C);
2603 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2604 assert(MD->isInstance() && "Member function must not be static!");
2606 MD = MD->getCanonicalDecl();
2607 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2608 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2609 CodeGenTypes &Types = CGM.getTypes();
2611 unsigned VBTableIndex = 0;
2612 llvm::Constant *FirstField;
2613 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2614 if (!MD->isVirtual()) {
2616 // Check whether the function has a computable LLVM signature.
2617 if (Types.isFuncTypeConvertible(FPT)) {
2618 // The function has a computable LLVM signature; use the correct type.
2619 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2621 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2622 // function type is incomplete.
2625 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2627 auto &VTableContext = CGM.getMicrosoftVTableContext();
2628 MicrosoftVTableContext::MethodVFTableLocation ML =
2629 VTableContext.getMethodVFTableLocation(MD);
2630 FirstField = EmitVirtualMemPtrThunk(MD, ML);
2631 // Include the vfptr adjustment if the method is in a non-primary vftable.
2632 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2634 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2637 if (VBTableIndex == 0 &&
2638 RD->getMSInheritanceModel() ==
2639 MSInheritanceAttr::Keyword_virtual_inheritance)
2640 NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD);
2642 // The rest of the fields are common with data member pointers.
2643 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2644 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2645 NonVirtualBaseAdjustment, VBTableIndex);
2648 /// Member pointers are the same if they're either bitwise identical *or* both
2649 /// null. Null-ness for function members is determined by the first field,
2650 /// while for data member pointers we must compare all fields.
2652 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2655 const MemberPointerType *MPT,
2657 CGBuilderTy &Builder = CGF.Builder;
2659 // Handle != comparisons by switching the sense of all boolean operations.
2660 llvm::ICmpInst::Predicate Eq;
2661 llvm::Instruction::BinaryOps And, Or;
2663 Eq = llvm::ICmpInst::ICMP_NE;
2664 And = llvm::Instruction::Or;
2665 Or = llvm::Instruction::And;
2667 Eq = llvm::ICmpInst::ICMP_EQ;
2668 And = llvm::Instruction::And;
2669 Or = llvm::Instruction::Or;
2672 // If this is a single field member pointer (single inheritance), this is a
2674 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2675 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2676 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2678 return Builder.CreateICmp(Eq, L, R);
2680 // Compare the first field.
2681 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2682 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2683 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2685 // Compare everything other than the first field.
2686 llvm::Value *Res = nullptr;
2687 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2688 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2689 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2690 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2691 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2693 Res = Builder.CreateBinOp(And, Res, Cmp);
2698 // Check if the first field is 0 if this is a function pointer.
2699 if (MPT->isMemberFunctionPointer()) {
2700 // (l1 == r1 && ...) || l0 == 0
2701 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2702 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2703 Res = Builder.CreateBinOp(Or, Res, IsZero);
2706 // Combine the comparison of the first field, which must always be true for
2707 // this comparison to succeeed.
2708 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2712 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2713 llvm::Value *MemPtr,
2714 const MemberPointerType *MPT) {
2715 CGBuilderTy &Builder = CGF.Builder;
2716 llvm::SmallVector<llvm::Constant *, 4> fields;
2717 // We only need one field for member functions.
2718 if (MPT->isMemberFunctionPointer())
2719 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2721 GetNullMemberPointerFields(MPT, fields);
2722 assert(!fields.empty());
2723 llvm::Value *FirstField = MemPtr;
2724 if (MemPtr->getType()->isStructTy())
2725 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2726 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2728 // For function member pointers, we only need to test the function pointer
2729 // field. The other fields if any can be garbage.
2730 if (MPT->isMemberFunctionPointer())
2733 // Otherwise, emit a series of compares and combine the results.
2734 for (int I = 1, E = fields.size(); I < E; ++I) {
2735 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2736 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2737 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2742 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2743 llvm::Constant *Val) {
2744 // Function pointers are null if the pointer in the first field is null.
2745 if (MPT->isMemberFunctionPointer()) {
2746 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2747 Val->getAggregateElement(0U) : Val;
2748 return FirstField->isNullValue();
2751 // If it's not a function pointer and it's zero initializable, we can easily
2753 if (isZeroInitializable(MPT) && Val->isNullValue())
2756 // Otherwise, break down all the fields for comparison. Hopefully these
2757 // little Constants are reused, while a big null struct might not be.
2758 llvm::SmallVector<llvm::Constant *, 4> Fields;
2759 GetNullMemberPointerFields(MPT, Fields);
2760 if (Fields.size() == 1) {
2761 assert(Val->getType()->isIntegerTy());
2762 return Val == Fields[0];
2766 for (I = 0, E = Fields.size(); I != E; ++I) {
2767 if (Val->getAggregateElement(I) != Fields[I])
2774 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2776 llvm::Value *VBPtrOffset,
2777 llvm::Value *VBTableOffset,
2778 llvm::Value **VBPtrOut) {
2779 CGBuilderTy &Builder = CGF.Builder;
2780 // Load the vbtable pointer from the vbptr in the instance.
2781 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2782 llvm::Value *VBPtr =
2783 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2784 if (VBPtrOut) *VBPtrOut = VBPtr;
2785 VBPtr = Builder.CreateBitCast(VBPtr,
2786 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2787 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2789 // Translate from byte offset to table index. It improves analyzability.
2790 llvm::Value *VBTableIndex = Builder.CreateAShr(
2791 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2792 "vbtindex", /*isExact=*/true);
2794 // Load an i32 offset from the vb-table.
2795 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2796 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2797 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2800 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2802 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2803 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2804 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2805 CGBuilderTy &Builder = CGF.Builder;
2806 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2807 llvm::BasicBlock *OriginalBB = nullptr;
2808 llvm::BasicBlock *SkipAdjustBB = nullptr;
2809 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2811 // In the unspecified inheritance model, there might not be a vbtable at all,
2812 // in which case we need to skip the virtual base lookup. If there is a
2813 // vbtable, the first entry is a no-op entry that gives back the original
2814 // base, so look for a virtual base adjustment offset of zero.
2816 OriginalBB = Builder.GetInsertBlock();
2817 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2818 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2819 llvm::Value *IsVirtual =
2820 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2822 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2823 CGF.EmitBlock(VBaseAdjustBB);
2826 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2827 // know the vbptr offset.
2829 CharUnits offs = CharUnits::Zero();
2830 if (!RD->hasDefinition()) {
2831 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2832 unsigned DiagID = Diags.getCustomDiagID(
2833 DiagnosticsEngine::Error,
2834 "member pointer representation requires a "
2835 "complete class type for %0 to perform this expression");
2836 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2837 } else if (RD->getNumVBases())
2838 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2839 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2841 llvm::Value *VBPtr = nullptr;
2842 llvm::Value *VBaseOffs =
2843 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2844 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2846 // Merge control flow with the case where we didn't have to adjust.
2847 if (VBaseAdjustBB) {
2848 Builder.CreateBr(SkipAdjustBB);
2849 CGF.EmitBlock(SkipAdjustBB);
2850 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2851 Phi->addIncoming(Base, OriginalBB);
2852 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2855 return AdjustedBase;
2858 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2859 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2860 const MemberPointerType *MPT) {
2861 assert(MPT->isMemberDataPointer());
2862 unsigned AS = Base->getType()->getPointerAddressSpace();
2864 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2865 CGBuilderTy &Builder = CGF.Builder;
2866 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2867 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2869 // Extract the fields we need, regardless of model. We'll apply them if we
2871 llvm::Value *FieldOffset = MemPtr;
2872 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2873 llvm::Value *VBPtrOffset = nullptr;
2874 if (MemPtr->getType()->isStructTy()) {
2875 // We need to extract values.
2877 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2878 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2879 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2880 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2881 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2884 if (VirtualBaseAdjustmentOffset) {
2885 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2890 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2892 // Apply the offset, which we assume is non-null.
2894 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2896 // Cast the address to the appropriate pointer type, adopting the address
2897 // space of the base pointer.
2898 return Builder.CreateBitCast(Addr, PType);
2902 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2905 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2906 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2907 E->getCastKind() == CK_ReinterpretMemberPointer);
2909 // Use constant emission if we can.
2910 if (isa<llvm::Constant>(Src))
2911 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2913 // We may be adding or dropping fields from the member pointer, so we need
2914 // both types and the inheritance models of both records.
2915 const MemberPointerType *SrcTy =
2916 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2917 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2918 bool IsFunc = SrcTy->isMemberFunctionPointer();
2920 // If the classes use the same null representation, reinterpret_cast is a nop.
2921 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2922 if (IsReinterpret && IsFunc)
2925 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2926 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2927 if (IsReinterpret &&
2928 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2931 CGBuilderTy &Builder = CGF.Builder;
2933 // Branch past the conversion if Src is null.
2934 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2935 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2937 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2938 // pointer value of the destination type.
2939 if (IsReinterpret) {
2940 // For reinterpret casts, sema ensures that src and dst are both functions
2941 // or data and have the same size, which means the LLVM types should match.
2942 assert(Src->getType() == DstNull->getType());
2943 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2946 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2947 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2948 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2949 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2950 CGF.EmitBlock(ConvertBB);
2952 llvm::Value *Dst = EmitNonNullMemberPointerConversion(
2953 SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src,
2956 Builder.CreateBr(ContinueBB);
2958 // In the continuation, choose between DstNull and Dst.
2959 CGF.EmitBlock(ContinueBB);
2960 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2961 Phi->addIncoming(DstNull, OriginalBB);
2962 Phi->addIncoming(Dst, ConvertBB);
2966 llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion(
2967 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
2968 CastExpr::path_const_iterator PathBegin,
2969 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
2970 CGBuilderTy &Builder) {
2971 const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2972 const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2973 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2974 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2975 bool IsFunc = SrcTy->isMemberFunctionPointer();
2976 bool IsConstant = isa<llvm::Constant>(Src);
2979 llvm::Value *FirstField = Src;
2980 llvm::Value *NonVirtualBaseAdjustment = getZeroInt();
2981 llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt();
2982 llvm::Value *VBPtrOffset = getZeroInt();
2983 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2984 // We need to extract values.
2986 FirstField = Builder.CreateExtractValue(Src, I++);
2987 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2988 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2989 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2990 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2991 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2992 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2995 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
2996 const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy;
2997 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
2999 // For data pointers, we adjust the field offset directly. For functions, we
3000 // have a separate field.
3001 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
3003 // The virtual inheritance model has a quirk: the virtual base table is always
3004 // referenced when dereferencing a member pointer even if the member pointer
3005 // is non-virtual. This is accounted for by adjusting the non-virtual offset
3006 // to point backwards to the top of the MDC from the first VBase. Undo this
3007 // adjustment to normalize the member pointer.
3008 llvm::Value *SrcVBIndexEqZero =
3009 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3010 if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3011 if (int64_t SrcOffsetToFirstVBase =
3012 getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) {
3013 llvm::Value *UndoSrcAdjustment = Builder.CreateSelect(
3015 llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase),
3017 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment);
3021 // A non-zero vbindex implies that we are dealing with a source member in a
3022 // floating virtual base in addition to some non-virtual offset. If the
3023 // vbindex is zero, we are dealing with a source that exists in a non-virtual,
3024 // fixed, base. The difference between these two cases is that the vbindex +
3025 // nvoffset *always* point to the member regardless of what context they are
3026 // evaluated in so long as the vbindex is adjusted. A member inside a fixed
3027 // base requires explicit nv adjustment.
3028 llvm::Constant *BaseClassOffset = llvm::ConstantInt::get(
3030 CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd)
3033 llvm::Value *NVDisp;
3034 if (IsDerivedToBase)
3035 NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj");
3037 NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj");
3039 NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt());
3041 // Update the vbindex to an appropriate value in the destination because
3042 // SrcRD's vbtable might not be a strict prefix of the one in DstRD.
3043 llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero;
3044 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) &&
3045 MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) {
3046 if (llvm::GlobalVariable *VDispMap =
3047 getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) {
3048 llvm::Value *VBIndex = Builder.CreateExactUDiv(
3049 VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4));
3051 llvm::Constant *Mapping = VDispMap->getInitializer();
3052 VirtualBaseAdjustmentOffset =
3053 Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex));
3055 llvm::Value *Idxs[] = {getZeroInt(), VBIndex};
3056 VirtualBaseAdjustmentOffset =
3057 Builder.CreateLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs));
3061 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3065 // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize
3066 // it to the offset of the vbptr.
3067 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) {
3068 llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get(
3070 getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity());
3072 Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset);
3075 // Likewise, apply a similar adjustment so that dereferencing the member
3076 // pointer correctly accounts for the distance between the start of the first
3077 // virtual base and the top of the MDC.
3078 if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3079 if (int64_t DstOffsetToFirstVBase =
3080 getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) {
3081 llvm::Value *DoDstAdjustment = Builder.CreateSelect(
3083 llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase),
3085 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment);
3089 // Recompose dst from the null struct and the adjusted fields from src.
3091 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
3094 Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy));
3096 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
3097 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3098 Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++);
3099 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3100 Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++);
3101 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3102 Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++);
3108 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
3109 llvm::Constant *Src) {
3110 const MemberPointerType *SrcTy =
3111 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3112 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3114 CastKind CK = E->getCastKind();
3116 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
3117 E->path_end(), Src);
3120 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
3121 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3122 CastExpr::path_const_iterator PathBegin,
3123 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
3124 assert(CK == CK_DerivedToBaseMemberPointer ||
3125 CK == CK_BaseToDerivedMemberPointer ||
3126 CK == CK_ReinterpretMemberPointer);
3127 // If src is null, emit a new null for dst. We can't return src because dst
3128 // might have a new representation.
3129 if (MemberPointerConstantIsNull(SrcTy, Src))
3130 return EmitNullMemberPointer(DstTy);
3132 // We don't need to do anything for reinterpret_casts of non-null member
3133 // pointers. We should only get here when the two type representations have
3135 if (CK == CK_ReinterpretMemberPointer)
3138 CGBuilderTy Builder(CGM.getLLVMContext());
3139 auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion(
3140 SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder));
3145 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3146 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
3147 llvm::Value *MemPtr, const MemberPointerType *MPT) {
3148 assert(MPT->isMemberFunctionPointer());
3149 const FunctionProtoType *FPT =
3150 MPT->getPointeeType()->castAs<FunctionProtoType>();
3151 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3152 llvm::FunctionType *FTy =
3153 CGM.getTypes().GetFunctionType(
3154 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
3155 CGBuilderTy &Builder = CGF.Builder;
3157 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3159 // Extract the fields we need, regardless of model. We'll apply them if we
3161 llvm::Value *FunctionPointer = MemPtr;
3162 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3163 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3164 llvm::Value *VBPtrOffset = nullptr;
3165 if (MemPtr->getType()->isStructTy()) {
3166 // We need to extract values.
3168 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3169 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3170 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3171 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3172 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3173 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3174 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3177 if (VirtualBaseAdjustmentOffset) {
3178 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
3182 if (NonVirtualBaseAdjustment) {
3183 // Apply the adjustment and cast back to the original struct type.
3184 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
3185 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3186 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
3189 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3192 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3193 return new MicrosoftCXXABI(CGM);
3196 // MS RTTI Overview:
3197 // The run time type information emitted by cl.exe contains 5 distinct types of
3198 // structures. Many of them reference each other.
3200 // TypeInfo: Static classes that are returned by typeid.
3202 // CompleteObjectLocator: Referenced by vftables. They contain information
3203 // required for dynamic casting, including OffsetFromTop. They also contain
3204 // a reference to the TypeInfo for the type and a reference to the
3205 // CompleteHierarchyDescriptor for the type.
3207 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3208 // Used during dynamic_cast to walk a class hierarchy. References a base
3209 // class array and the size of said array.
3211 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3212 // somewhat of a misnomer because the most derived class is also in the list
3213 // as well as multiple copies of virtual bases (if they occur multiple times
3214 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3215 // every path in the hierarchy, in pre-order depth first order. Note, we do
3216 // not declare a specific llvm type for BaseClassArray, it's merely an array
3217 // of BaseClassDescriptor pointers.
3219 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3220 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3221 // BaseClassArray is. It contains information about a class within a
3222 // hierarchy such as: is this base is ambiguous and what is its offset in the
3223 // vbtable. The names of the BaseClassDescriptors have all of their fields
3224 // mangled into them so they can be aggressively deduplicated by the linker.
3226 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3227 StringRef MangledName("\01??_7type_info@@6B@");
3228 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3230 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3232 llvm::GlobalVariable::ExternalLinkage,
3233 /*Initializer=*/nullptr, MangledName);
3238 /// \brief A Helper struct that stores information about a class in a class
3239 /// hierarchy. The information stored in these structs struct is used during
3240 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3241 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3242 // implicit depth first pre-order tree connectivity. getFirstChild and
3243 // getNextSibling allow us to walk the tree efficiently.
3244 struct MSRTTIClass {
3246 IsPrivateOnPath = 1 | 8,
3250 HasHierarchyDescriptor = 64
3252 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3253 uint32_t initialize(const MSRTTIClass *Parent,
3254 const CXXBaseSpecifier *Specifier);
3256 MSRTTIClass *getFirstChild() { return this + 1; }
3257 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3258 return Child + 1 + Child->NumBases;
3261 const CXXRecordDecl *RD, *VirtualRoot;
3262 uint32_t Flags, NumBases, OffsetInVBase;
3265 /// \brief Recursively initialize the base class array.
3266 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3267 const CXXBaseSpecifier *Specifier) {
3268 Flags = HasHierarchyDescriptor;
3270 VirtualRoot = nullptr;
3273 if (Specifier->getAccessSpecifier() != AS_public)
3274 Flags |= IsPrivate | IsPrivateOnPath;
3275 if (Specifier->isVirtual()) {
3280 if (Parent->Flags & IsPrivateOnPath)
3281 Flags |= IsPrivateOnPath;
3282 VirtualRoot = Parent->VirtualRoot;
3283 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3284 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3288 MSRTTIClass *Child = getFirstChild();
3289 for (const CXXBaseSpecifier &Base : RD->bases()) {
3290 NumBases += Child->initialize(this, &Base) + 1;
3291 Child = getNextChild(Child);
3296 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3297 switch (Ty->getLinkage()) {
3299 case InternalLinkage:
3300 case UniqueExternalLinkage:
3301 return llvm::GlobalValue::InternalLinkage;
3303 case VisibleNoLinkage:
3304 case ExternalLinkage:
3305 return llvm::GlobalValue::LinkOnceODRLinkage;
3307 llvm_unreachable("Invalid linkage!");
3310 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3311 /// calls to the module and information about the most derived class in a
3313 struct MSRTTIBuilder {
3315 HasBranchingHierarchy = 1,
3316 HasVirtualBranchingHierarchy = 2,
3317 HasAmbiguousBases = 4
3320 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3321 : CGM(ABI.CGM), Context(CGM.getContext()),
3322 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3323 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3326 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3327 llvm::GlobalVariable *
3328 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3329 llvm::GlobalVariable *getClassHierarchyDescriptor();
3330 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3333 ASTContext &Context;
3334 llvm::LLVMContext &VMContext;
3335 llvm::Module &Module;
3336 const CXXRecordDecl *RD;
3337 llvm::GlobalVariable::LinkageTypes Linkage;
3338 MicrosoftCXXABI &ABI;
3343 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3345 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3346 const CXXRecordDecl *RD) {
3347 Classes.push_back(MSRTTIClass(RD));
3348 for (const CXXBaseSpecifier &Base : RD->bases())
3349 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3352 /// \brief Find ambiguity among base classes.
3354 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3355 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3356 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3357 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3358 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3359 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3360 !VirtualBases.insert(Class->RD).second) {
3361 Class = MSRTTIClass::getNextChild(Class);
3364 if (!UniqueBases.insert(Class->RD).second)
3365 AmbiguousBases.insert(Class->RD);
3368 if (AmbiguousBases.empty())
3370 for (MSRTTIClass &Class : Classes)
3371 if (AmbiguousBases.count(Class.RD))
3372 Class.Flags |= MSRTTIClass::IsAmbiguous;
3375 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3376 SmallString<256> MangledName;
3378 llvm::raw_svector_ostream Out(MangledName);
3379 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3382 // Check to see if we've already declared this ClassHierarchyDescriptor.
3383 if (auto CHD = Module.getNamedGlobal(MangledName))
3386 // Serialize the class hierarchy and initialize the CHD Fields.
3387 SmallVector<MSRTTIClass, 8> Classes;
3388 serializeClassHierarchy(Classes, RD);
3389 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3390 detectAmbiguousBases(Classes);
3392 for (auto Class : Classes) {
3393 if (Class.RD->getNumBases() > 1)
3394 Flags |= HasBranchingHierarchy;
3395 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3396 // believe the field isn't actually used.
3397 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3398 Flags |= HasAmbiguousBases;
3400 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3401 Flags |= HasVirtualBranchingHierarchy;
3402 // These gep indices are used to get the address of the first element of the
3403 // base class array.
3404 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3405 llvm::ConstantInt::get(CGM.IntTy, 0)};
3407 // Forward-declare the class hierarchy descriptor
3408 auto Type = ABI.getClassHierarchyDescriptorType();
3409 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3410 /*Initializer=*/nullptr,
3411 StringRef(MangledName));
3412 if (CHD->isWeakForLinker())
3413 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3415 auto *Bases = getBaseClassArray(Classes);
3417 // Initialize the base class ClassHierarchyDescriptor.
3418 llvm::Constant *Fields[] = {
3419 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3420 llvm::ConstantInt::get(CGM.IntTy, Flags),
3421 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3422 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3423 Bases->getValueType(), Bases,
3424 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3426 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3430 llvm::GlobalVariable *
3431 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3432 SmallString<256> MangledName;
3434 llvm::raw_svector_ostream Out(MangledName);
3435 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3438 // Forward-declare the base class array.
3439 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3440 // mode) bytes of padding. We provide a pointer sized amount of padding by
3441 // adding +1 to Classes.size(). The sections have pointer alignment and are
3442 // marked pick-any so it shouldn't matter.
3443 llvm::Type *PtrType = ABI.getImageRelativeType(
3444 ABI.getBaseClassDescriptorType()->getPointerTo());
3445 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3447 new llvm::GlobalVariable(Module, ArrType,
3448 /*Constant=*/true, Linkage,
3449 /*Initializer=*/nullptr, StringRef(MangledName));
3450 if (BCA->isWeakForLinker())
3451 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3453 // Initialize the BaseClassArray.
3454 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3455 for (MSRTTIClass &Class : Classes)
3456 BaseClassArrayData.push_back(
3457 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3458 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3459 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3463 llvm::GlobalVariable *
3464 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3465 // Compute the fields for the BaseClassDescriptor. They are computed up front
3466 // because they are mangled into the name of the object.
3467 uint32_t OffsetInVBTable = 0;
3468 int32_t VBPtrOffset = -1;
3469 if (Class.VirtualRoot) {
3470 auto &VTableContext = CGM.getMicrosoftVTableContext();
3471 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3472 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3475 SmallString<256> MangledName;
3477 llvm::raw_svector_ostream Out(MangledName);
3478 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3479 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3483 // Check to see if we've already declared this object.
3484 if (auto BCD = Module.getNamedGlobal(MangledName))
3487 // Forward-declare the base class descriptor.
3488 auto Type = ABI.getBaseClassDescriptorType();
3490 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3491 /*Initializer=*/nullptr, StringRef(MangledName));
3492 if (BCD->isWeakForLinker())
3493 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3495 // Initialize the BaseClassDescriptor.
3496 llvm::Constant *Fields[] = {
3497 ABI.getImageRelativeConstant(
3498 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3499 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3500 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3501 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3502 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3503 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3504 ABI.getImageRelativeConstant(
3505 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3507 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3511 llvm::GlobalVariable *
3512 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3513 SmallString<256> MangledName;
3515 llvm::raw_svector_ostream Out(MangledName);
3516 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3519 // Check to see if we've already computed this complete object locator.
3520 if (auto COL = Module.getNamedGlobal(MangledName))
3523 // Compute the fields of the complete object locator.
3524 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3525 int VFPtrOffset = 0;
3526 // The offset includes the vtordisp if one exists.
3527 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3528 if (Context.getASTRecordLayout(RD)
3529 .getVBaseOffsetsMap()
3531 ->second.hasVtorDisp())
3532 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3534 // Forward-declare the complete object locator.
3535 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3536 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3537 /*Initializer=*/nullptr, StringRef(MangledName));
3539 // Initialize the CompleteObjectLocator.
3540 llvm::Constant *Fields[] = {
3541 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3542 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3543 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3544 ABI.getImageRelativeConstant(
3545 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3546 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3547 ABI.getImageRelativeConstant(COL),
3549 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3550 if (!ABI.isImageRelative())
3551 FieldsRef = FieldsRef.drop_back();
3552 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3553 if (COL->isWeakForLinker())
3554 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3558 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3559 bool &IsConst, bool &IsVolatile) {
3560 T = Context.getExceptionObjectType(T);
3562 // C++14 [except.handle]p3:
3563 // A handler is a match for an exception object of type E if [...]
3564 // - the handler is of type cv T or const T& where T is a pointer type and
3565 // E is a pointer type that can be converted to T by [...]
3566 // - a qualification conversion
3569 QualType PointeeType = T->getPointeeType();
3570 if (!PointeeType.isNull()) {
3571 IsConst = PointeeType.isConstQualified();
3572 IsVolatile = PointeeType.isVolatileQualified();
3575 // Member pointer types like "const int A::*" are represented by having RTTI
3576 // for "int A::*" and separately storing the const qualifier.
3577 if (const auto *MPTy = T->getAs<MemberPointerType>())
3578 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3581 // Pointer types like "const int * const *" are represented by having RTTI
3582 // for "const int **" and separately storing the const qualifier.
3583 if (T->isPointerType())
3584 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3590 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3591 QualType CatchHandlerType) {
3592 // TypeDescriptors for exceptions never have qualified pointer types,
3593 // qualifiers are stored seperately in order to support qualification
3595 bool IsConst, IsVolatile;
3596 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3598 bool IsReference = CatchHandlerType->isReferenceType();
3608 SmallString<256> MangledName;
3610 llvm::raw_svector_ostream Out(MangledName);
3611 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3614 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3615 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3617 llvm::Constant *Fields[] = {
3618 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3619 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3621 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3622 auto *Var = new llvm::GlobalVariable(
3623 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3624 llvm::GlobalValue::PrivateLinkage,
3625 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3626 StringRef(MangledName));
3627 Var->setUnnamedAddr(true);
3628 Var->setSection("llvm.metadata");
3632 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3633 /// llvm::GlobalVariable * because different type descriptors have different
3634 /// types, and need to be abstracted. They are abstracting by casting the
3635 /// address to an Int8PtrTy.
3636 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3637 SmallString<256> MangledName;
3639 llvm::raw_svector_ostream Out(MangledName);
3640 getMangleContext().mangleCXXRTTI(Type, Out);
3643 // Check to see if we've already declared this TypeDescriptor.
3644 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3645 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3647 // Compute the fields for the TypeDescriptor.
3648 SmallString<256> TypeInfoString;
3650 llvm::raw_svector_ostream Out(TypeInfoString);
3651 getMangleContext().mangleCXXRTTIName(Type, Out);
3654 // Declare and initialize the TypeDescriptor.
3655 llvm::Constant *Fields[] = {
3656 getTypeInfoVTable(CGM), // VFPtr
3657 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3658 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3659 llvm::StructType *TypeDescriptorType =
3660 getTypeDescriptorType(TypeInfoString);
3661 auto *Var = new llvm::GlobalVariable(
3662 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3663 getLinkageForRTTI(Type),
3664 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3665 StringRef(MangledName));
3666 if (Var->isWeakForLinker())
3667 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3668 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3671 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3672 llvm::GlobalVariable *
3673 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3674 const VPtrInfo *Info) {
3675 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3678 static void emitCXXConstructor(CodeGenModule &CGM,
3679 const CXXConstructorDecl *ctor,
3680 StructorType ctorType) {
3681 // There are no constructor variants, always emit the complete destructor.
3682 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3683 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3686 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3687 StructorType dtorType) {
3688 // The complete destructor is equivalent to the base destructor for
3689 // classes with no virtual bases, so try to emit it as an alias.
3690 if (!dtor->getParent()->getNumVBases() &&
3691 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3692 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3693 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3694 if (ProducedAlias) {
3695 if (dtorType == StructorType::Complete)
3697 if (dtor->isVirtual())
3698 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3702 // The base destructor is equivalent to the base destructor of its
3703 // base class if there is exactly one non-virtual base class with a
3704 // non-trivial destructor, there are no fields with a non-trivial
3705 // destructor, and the body of the destructor is trivial.
3706 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3709 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3710 if (Fn->isWeakForLinker())
3711 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3714 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3715 StructorType Type) {
3716 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3717 emitCXXConstructor(CGM, CD, Type);
3720 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3724 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3726 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3728 // Calculate the mangled name.
3729 SmallString<256> ThunkName;
3730 llvm::raw_svector_ostream Out(ThunkName);
3731 getMangleContext().mangleCXXCtor(CD, CT, Out);
3734 // If the thunk has been generated previously, just return it.
3735 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3736 return cast<llvm::Function>(GV);
3738 // Create the llvm::Function.
3739 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3740 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3741 const CXXRecordDecl *RD = CD->getParent();
3742 QualType RecordTy = getContext().getRecordType(RD);
3743 llvm::Function *ThunkFn = llvm::Function::Create(
3744 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3745 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3746 FnInfo.getEffectiveCallingConvention()));
3747 if (ThunkFn->isWeakForLinker())
3748 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
3749 bool IsCopy = CT == Ctor_CopyingClosure;
3752 CodeGenFunction CGF(CGM);
3753 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3755 // Build FunctionArgs.
3756 FunctionArgList FunctionArgs;
3758 // A constructor always starts with a 'this' pointer as its first argument.
3759 buildThisParam(CGF, FunctionArgs);
3761 // Following the 'this' pointer is a reference to the source object that we
3762 // are copying from.
3763 ImplicitParamDecl SrcParam(
3764 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3765 getContext().getLValueReferenceType(RecordTy,
3766 /*SpelledAsLValue=*/true));
3768 FunctionArgs.push_back(&SrcParam);
3770 // Constructors for classes which utilize virtual bases have an additional
3771 // parameter which indicates whether or not it is being delegated to by a more
3772 // derived constructor.
3773 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3774 &getContext().Idents.get("is_most_derived"),
3775 getContext().IntTy);
3776 // Only add the parameter to the list if thie class has virtual bases.
3777 if (RD->getNumVBases() > 0)
3778 FunctionArgs.push_back(&IsMostDerived);
3780 // Start defining the function.
3781 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3782 FunctionArgs, CD->getLocation(), SourceLocation());
3784 llvm::Value *This = getThisValue(CGF);
3786 llvm::Value *SrcVal =
3787 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3792 // Push the this ptr.
3793 Args.add(RValue::get(This), CD->getThisType(getContext()));
3795 // Push the src ptr.
3797 Args.add(RValue::get(SrcVal), SrcParam.getType());
3799 // Add the rest of the default arguments.
3800 std::vector<Stmt *> ArgVec;
3801 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3802 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3803 assert(DefaultArg && "sema forgot to instantiate default args");
3804 ArgVec.push_back(DefaultArg);
3807 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3809 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3810 CGF.EmitCallArgs(Args, FPT, llvm::makeArrayRef(ArgVec), CD, IsCopy ? 1 : 0);
3812 // Insert any ABI-specific implicit constructor arguments.
3813 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3814 /*ForVirtualBase=*/false,
3815 /*Delegating=*/false, Args);
3817 // Call the destructor with our arguments.
3818 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3819 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3820 Args, CD, Ctor_Complete, ExtraArgs);
3821 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3823 Cleanups.ForceCleanup();
3825 // Emit the ret instruction, remove any temporary instructions created for the
3827 CGF.FinishFunction(SourceLocation());
3832 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3834 int32_t VBPtrOffset,
3836 assert(!T->isReferenceType());
3838 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3839 const CXXConstructorDecl *CD =
3840 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3841 CXXCtorType CT = Ctor_Complete;
3843 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3844 CT = Ctor_CopyingClosure;
3846 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3847 SmallString<256> MangledName;
3849 llvm::raw_svector_ostream Out(MangledName);
3850 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3851 VBPtrOffset, VBIndex, Out);
3853 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3854 return getImageRelativeConstant(GV);
3856 // The TypeDescriptor is used by the runtime to determine if a catch handler
3857 // is appropriate for the exception object.
3858 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3860 // The runtime is responsible for calling the copy constructor if the
3861 // exception is caught by value.
3862 llvm::Constant *CopyCtor;
3864 if (CT == Ctor_CopyingClosure)
3865 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3867 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3869 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3871 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3873 CopyCtor = getImageRelativeConstant(CopyCtor);
3875 bool IsScalar = !RD;
3876 bool HasVirtualBases = false;
3877 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3878 QualType PointeeType = T;
3879 if (T->isPointerType())
3880 PointeeType = T->getPointeeType();
3881 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3882 HasVirtualBases = RD->getNumVBases() > 0;
3883 if (IdentifierInfo *II = RD->getIdentifier())
3884 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3887 // Encode the relevant CatchableType properties into the Flags bitfield.
3888 // FIXME: Figure out how bits 2 or 8 can get set.
3892 if (HasVirtualBases)
3897 llvm::Constant *Fields[] = {
3898 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3899 TD, // TypeDescriptor
3900 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3901 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3902 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3903 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3904 CopyCtor // CopyCtor
3906 llvm::StructType *CTType = getCatchableTypeType();
3907 auto *GV = new llvm::GlobalVariable(
3908 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3909 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3910 GV->setUnnamedAddr(true);
3911 GV->setSection(".xdata");
3912 if (GV->isWeakForLinker())
3913 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3914 return getImageRelativeConstant(GV);
3917 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3918 assert(!T->isReferenceType());
3920 // See if we've already generated a CatchableTypeArray for this type before.
3921 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3925 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3926 // using a SmallSetVector. Duplicates may arise due to virtual bases
3927 // occurring more than once in the hierarchy.
3928 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3930 // C++14 [except.handle]p3:
3931 // A handler is a match for an exception object of type E if [...]
3932 // - the handler is of type cv T or cv T& and T is an unambiguous public
3933 // base class of E, or
3934 // - the handler is of type cv T or const T& where T is a pointer type and
3935 // E is a pointer type that can be converted to T by [...]
3936 // - a standard pointer conversion (4.10) not involving conversions to
3937 // pointers to private or protected or ambiguous classes
3938 const CXXRecordDecl *MostDerivedClass = nullptr;
3939 bool IsPointer = T->isPointerType();
3941 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3943 MostDerivedClass = T->getAsCXXRecordDecl();
3945 // Collect all the unambiguous public bases of the MostDerivedClass.
3946 if (MostDerivedClass) {
3947 const ASTContext &Context = getContext();
3948 const ASTRecordLayout &MostDerivedLayout =
3949 Context.getASTRecordLayout(MostDerivedClass);
3950 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3951 SmallVector<MSRTTIClass, 8> Classes;
3952 serializeClassHierarchy(Classes, MostDerivedClass);
3953 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3954 detectAmbiguousBases(Classes);
3955 for (const MSRTTIClass &Class : Classes) {
3956 // Skip any ambiguous or private bases.
3958 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3960 // Write down how to convert from a derived pointer to a base pointer.
3961 uint32_t OffsetInVBTable = 0;
3962 int32_t VBPtrOffset = -1;
3963 if (Class.VirtualRoot) {
3965 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3966 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3969 // Turn our record back into a pointer if the exception object is a
3971 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3973 RTTITy = Context.getPointerType(RTTITy);
3974 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3975 VBPtrOffset, OffsetInVBTable));
3979 // C++14 [except.handle]p3:
3980 // A handler is a match for an exception object of type E if
3981 // - The handler is of type cv T or cv T& and E and T are the same type
3982 // (ignoring the top-level cv-qualifiers)
3983 CatchableTypes.insert(getCatchableType(T));
3985 // C++14 [except.handle]p3:
3986 // A handler is a match for an exception object of type E if
3987 // - the handler is of type cv T or const T& where T is a pointer type and
3988 // E is a pointer type that can be converted to T by [...]
3989 // - a standard pointer conversion (4.10) not involving conversions to
3990 // pointers to private or protected or ambiguous classes
3992 // C++14 [conv.ptr]p2:
3993 // A prvalue of type "pointer to cv T," where T is an object type, can be
3994 // converted to a prvalue of type "pointer to cv void".
3995 if (IsPointer && T->getPointeeType()->isObjectType())
3996 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3998 // C++14 [except.handle]p3:
3999 // A handler is a match for an exception object of type E if [...]
4000 // - the handler is of type cv T or const T& where T is a pointer or
4001 // pointer to member type and E is std::nullptr_t.
4003 // We cannot possibly list all possible pointer types here, making this
4004 // implementation incompatible with the standard. However, MSVC includes an
4005 // entry for pointer-to-void in this case. Let's do the same.
4006 if (T->isNullPtrType())
4007 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4009 uint32_t NumEntries = CatchableTypes.size();
4010 llvm::Type *CTType =
4011 getImageRelativeType(getCatchableTypeType()->getPointerTo());
4012 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
4013 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
4014 llvm::Constant *Fields[] = {
4015 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
4016 llvm::ConstantArray::get(
4017 AT, llvm::makeArrayRef(CatchableTypes.begin(),
4018 CatchableTypes.end())) // CatchableTypes
4020 SmallString<256> MangledName;
4022 llvm::raw_svector_ostream Out(MangledName);
4023 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
4025 CTA = new llvm::GlobalVariable(
4026 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
4027 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
4028 CTA->setUnnamedAddr(true);
4029 CTA->setSection(".xdata");
4030 if (CTA->isWeakForLinker())
4031 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
4035 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
4036 bool IsConst, IsVolatile;
4037 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
4039 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
4040 // the exception object may be caught as.
4041 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
4042 // The first field in a CatchableTypeArray is the number of CatchableTypes.
4043 // This is used as a component of the mangled name which means that we need to
4044 // know what it is in order to see if we have previously generated the
4046 uint32_t NumEntries =
4047 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
4048 ->getLimitedValue();
4050 SmallString<256> MangledName;
4052 llvm::raw_svector_ostream Out(MangledName);
4053 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
4057 // Reuse a previously generated ThrowInfo if we have generated an appropriate
4059 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
4062 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
4063 // be at least as CV qualified. Encode this requirement into the Flags
4071 // The cleanup-function (a destructor) must be called when the exception
4072 // object's lifetime ends.
4073 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
4074 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4075 if (CXXDestructorDecl *DtorD = RD->getDestructor())
4076 if (!DtorD->isTrivial())
4077 CleanupFn = llvm::ConstantExpr::getBitCast(
4078 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
4080 // This is unused as far as we can tell, initialize it to null.
4081 llvm::Constant *ForwardCompat =
4082 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
4083 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
4084 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
4085 llvm::StructType *TIType = getThrowInfoType();
4086 llvm::Constant *Fields[] = {
4087 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4088 getImageRelativeConstant(CleanupFn), // CleanupFn
4089 ForwardCompat, // ForwardCompat
4090 PointerToCatchableTypes // CatchableTypeArray
4092 auto *GV = new llvm::GlobalVariable(
4093 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
4094 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
4095 GV->setUnnamedAddr(true);
4096 GV->setSection(".xdata");
4097 if (GV->isWeakForLinker())
4098 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4102 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
4103 const Expr *SubExpr = E->getSubExpr();
4104 QualType ThrowType = SubExpr->getType();
4105 // The exception object lives on the stack and it's address is passed to the
4106 // runtime function.
4107 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
4108 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4111 // The so-called ThrowInfo is used to describe how the exception object may be
4113 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4115 // Call into the runtime to throw the exception.
4116 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
4117 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);