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 "CGCleanup.h"
19 #include "CGVTables.h"
20 #include "CodeGenModule.h"
21 #include "CodeGenTypes.h"
22 #include "ConstantBuilder.h"
23 #include "TargetInfo.h"
24 #include "clang/AST/Decl.h"
25 #include "clang/AST/DeclCXX.h"
26 #include "clang/AST/StmtCXX.h"
27 #include "clang/AST/VTableBuilder.h"
28 #include "llvm/ADT/StringExtras.h"
29 #include "llvm/ADT/StringSet.h"
30 #include "llvm/IR/CallSite.h"
31 #include "llvm/IR/Intrinsics.h"
33 using namespace clang;
34 using namespace CodeGen;
38 /// Holds all the vbtable globals for a given class.
39 struct VBTableGlobals {
40 const VPtrInfoVector *VBTables;
41 SmallVector<llvm::GlobalVariable *, 2> Globals;
44 class MicrosoftCXXABI : public CGCXXABI {
46 MicrosoftCXXABI(CodeGenModule &CGM)
47 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
48 ClassHierarchyDescriptorType(nullptr),
49 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
50 ThrowInfoType(nullptr) {}
52 bool HasThisReturn(GlobalDecl GD) const override;
53 bool hasMostDerivedReturn(GlobalDecl GD) const override;
55 bool classifyReturnType(CGFunctionInfo &FI) const override;
57 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
59 bool isSRetParameterAfterThis() const override { return true; }
61 bool isThisCompleteObject(GlobalDecl GD) const override {
62 // The Microsoft ABI doesn't use separate complete-object vs.
63 // base-object variants of constructors, but it does of destructors.
64 if (isa<CXXDestructorDecl>(GD.getDecl())) {
65 switch (GD.getDtorType()) {
73 case Dtor_Comdat: llvm_unreachable("emitting dtor comdat as function?");
75 llvm_unreachable("bad dtor kind");
82 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
83 FunctionArgList &Args) const override {
84 assert(Args.size() >= 2 &&
85 "expected the arglist to have at least two args!");
86 // The 'most_derived' parameter goes second if the ctor is variadic and
88 if (CD->getParent()->getNumVBases() > 0 &&
89 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
94 std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD) override {
95 std::vector<CharUnits> VBPtrOffsets;
96 const ASTContext &Context = getContext();
97 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
99 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
100 for (const std::unique_ptr<VPtrInfo> &VBT : *VBGlobals.VBTables) {
101 const ASTRecordLayout &SubobjectLayout =
102 Context.getASTRecordLayout(VBT->IntroducingObject);
103 CharUnits Offs = VBT->NonVirtualOffset;
104 Offs += SubobjectLayout.getVBPtrOffset();
105 if (VBT->getVBaseWithVPtr())
106 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
107 VBPtrOffsets.push_back(Offs);
109 llvm::array_pod_sort(VBPtrOffsets.begin(), VBPtrOffsets.end());
113 StringRef GetPureVirtualCallName() override { return "_purecall"; }
114 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
116 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
117 Address Ptr, QualType ElementType,
118 const CXXDestructorDecl *Dtor) override;
120 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
121 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
123 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
125 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
126 const VPtrInfo &Info);
128 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
130 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override;
132 /// MSVC needs an extra flag to indicate a catchall.
133 CatchTypeInfo getCatchAllTypeInfo() override {
134 return CatchTypeInfo{nullptr, 0x40};
137 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
138 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
139 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
141 llvm::Type *StdTypeInfoPtrTy) override;
143 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
144 QualType SrcRecordTy) override;
146 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, Address Value,
147 QualType SrcRecordTy, QualType DestTy,
148 QualType DestRecordTy,
149 llvm::BasicBlock *CastEnd) override;
151 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, Address Value,
152 QualType SrcRecordTy,
153 QualType DestTy) override;
155 bool EmitBadCastCall(CodeGenFunction &CGF) override;
156 bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const override {
161 GetVirtualBaseClassOffset(CodeGenFunction &CGF, Address This,
162 const CXXRecordDecl *ClassDecl,
163 const CXXRecordDecl *BaseClassDecl) override;
166 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
167 const CXXRecordDecl *RD) override;
170 EmitDtorCompleteObjectHandler(CodeGenFunction &CGF);
172 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
173 const CXXRecordDecl *RD) override;
175 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
177 // Background on MSVC destructors
178 // ==============================
180 // Both Itanium and MSVC ABIs have destructor variants. The variant names
181 // roughly correspond in the following way:
183 // Base -> no name, just ~Class
184 // Complete -> vbase destructor
185 // Deleting -> scalar deleting destructor
186 // vector deleting destructor
188 // The base and complete destructors are the same as in Itanium, although the
189 // complete destructor does not accept a VTT parameter when there are virtual
190 // bases. A separate mechanism involving vtordisps is used to ensure that
191 // virtual methods of destroyed subobjects are not called.
193 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
194 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
195 // pointer points to an array. The scalar deleting destructor assumes that
196 // bit 2 is zero, and therefore does not contain a loop.
198 // For virtual destructors, only one entry is reserved in the vftable, and it
199 // always points to the vector deleting destructor. The vector deleting
200 // destructor is the most general, so it can be used to destroy objects in
201 // place, delete single heap objects, or delete arrays.
203 // A TU defining a non-inline destructor is only guaranteed to emit a base
204 // destructor, and all of the other variants are emitted on an as-needed basis
205 // in COMDATs. Because a non-base destructor can be emitted in a TU that
206 // lacks a definition for the destructor, non-base destructors must always
207 // delegate to or alias the base destructor.
209 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
210 SmallVectorImpl<CanQualType> &ArgTys) override;
212 /// Non-base dtors should be emitted as delegating thunks in this ABI.
213 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
214 CXXDtorType DT) const override {
215 return DT != Dtor_Base;
218 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
220 const CXXRecordDecl *
221 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
222 MD = MD->getCanonicalDecl();
223 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
224 MicrosoftVTableContext::MethodVFTableLocation ML =
225 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
226 // The vbases might be ordered differently in the final overrider object
227 // and the complete object, so the "this" argument may sometimes point to
228 // memory that has no particular type (e.g. past the complete object).
229 // In this case, we just use a generic pointer type.
230 // FIXME: might want to have a more precise type in the non-virtual
231 // multiple inheritance case.
232 if (ML.VBase || !ML.VFPtrOffset.isZero())
235 return MD->getParent();
239 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
241 bool VirtualCall) override;
243 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
244 FunctionArgList &Params) override;
246 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
247 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
249 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
251 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
252 const CXXConstructorDecl *D,
253 CXXCtorType Type, bool ForVirtualBase,
255 CallArgList &Args) override;
257 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
258 CXXDtorType Type, bool ForVirtualBase,
259 bool Delegating, Address This) override;
261 void emitVTableTypeMetadata(const VPtrInfo &Info, const CXXRecordDecl *RD,
262 llvm::GlobalVariable *VTable);
264 void emitVTableDefinitions(CodeGenVTables &CGVT,
265 const CXXRecordDecl *RD) override;
267 bool isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
268 CodeGenFunction::VPtr Vptr) override;
270 /// Don't initialize vptrs if dynamic class
271 /// is marked with with the 'novtable' attribute.
272 bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) override {
273 return !VTableClass->hasAttr<MSNoVTableAttr>();
277 getVTableAddressPoint(BaseSubobject Base,
278 const CXXRecordDecl *VTableClass) override;
280 llvm::Value *getVTableAddressPointInStructor(
281 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
282 BaseSubobject Base, const CXXRecordDecl *NearestVBase) override;
285 getVTableAddressPointForConstExpr(BaseSubobject Base,
286 const CXXRecordDecl *VTableClass) override;
288 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
289 CharUnits VPtrOffset) override;
291 CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
292 Address This, llvm::Type *Ty,
293 SourceLocation Loc) override;
295 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
296 const CXXDestructorDecl *Dtor,
297 CXXDtorType DtorType,
299 const CXXMemberCallExpr *CE) override;
301 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
302 CallArgList &CallArgs) override {
303 assert(GD.getDtorType() == Dtor_Deleting &&
304 "Only deleting destructor thunks are available in this ABI");
305 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
309 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
311 llvm::GlobalVariable *
312 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
313 llvm::GlobalVariable::LinkageTypes Linkage);
315 llvm::GlobalVariable *
316 getAddrOfVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
317 const CXXRecordDecl *DstRD) {
318 SmallString<256> OutName;
319 llvm::raw_svector_ostream Out(OutName);
320 getMangleContext().mangleCXXVirtualDisplacementMap(SrcRD, DstRD, Out);
321 StringRef MangledName = OutName.str();
323 if (auto *VDispMap = CGM.getModule().getNamedGlobal(MangledName))
326 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
327 unsigned NumEntries = 1 + SrcRD->getNumVBases();
328 SmallVector<llvm::Constant *, 4> Map(NumEntries,
329 llvm::UndefValue::get(CGM.IntTy));
330 Map[0] = llvm::ConstantInt::get(CGM.IntTy, 0);
331 bool AnyDifferent = false;
332 for (const auto &I : SrcRD->vbases()) {
333 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
334 if (!DstRD->isVirtuallyDerivedFrom(VBase))
337 unsigned SrcVBIndex = VTContext.getVBTableIndex(SrcRD, VBase);
338 unsigned DstVBIndex = VTContext.getVBTableIndex(DstRD, VBase);
339 Map[SrcVBIndex] = llvm::ConstantInt::get(CGM.IntTy, DstVBIndex * 4);
340 AnyDifferent |= SrcVBIndex != DstVBIndex;
342 // This map would be useless, don't use it.
346 llvm::ArrayType *VDispMapTy = llvm::ArrayType::get(CGM.IntTy, Map.size());
347 llvm::Constant *Init = llvm::ConstantArray::get(VDispMapTy, Map);
348 llvm::GlobalValue::LinkageTypes Linkage =
349 SrcRD->isExternallyVisible() && DstRD->isExternallyVisible()
350 ? llvm::GlobalValue::LinkOnceODRLinkage
351 : llvm::GlobalValue::InternalLinkage;
352 auto *VDispMap = new llvm::GlobalVariable(
353 CGM.getModule(), VDispMapTy, /*Constant=*/true, Linkage,
354 /*Initializer=*/Init, MangledName);
358 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
359 llvm::GlobalVariable *GV) const;
361 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
362 GlobalDecl GD, bool ReturnAdjustment) override {
363 // Never dllimport/dllexport thunks.
364 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
367 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
369 if (Linkage == GVA_Internal)
370 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
371 else if (ReturnAdjustment)
372 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
374 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
377 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, Address This,
378 const ThisAdjustment &TA) override;
380 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, Address Ret,
381 const ReturnAdjustment &RA) override;
383 void EmitThreadLocalInitFuncs(
384 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
385 ArrayRef<llvm::Function *> CXXThreadLocalInits,
386 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) override;
388 bool usesThreadWrapperFunction() const override { return false; }
389 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
390 QualType LValType) override;
392 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
393 llvm::GlobalVariable *DeclPtr,
394 bool PerformInit) override;
395 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
396 llvm::Constant *Dtor, llvm::Constant *Addr) override;
398 // ==== Notes on array cookies =========
400 // MSVC seems to only use cookies when the class has a destructor; a
401 // two-argument usual array deallocation function isn't sufficient.
403 // For example, this code prints "100" and "1":
406 // void *operator new[](size_t sz) {
407 // printf("%u\n", sz);
408 // return malloc(sz);
410 // void operator delete[](void *p, size_t sz) {
411 // printf("%u\n", sz);
416 // A *p = new A[100];
419 // Whereas it prints "104" and "104" if you give A a destructor.
421 bool requiresArrayCookie(const CXXDeleteExpr *expr,
422 QualType elementType) override;
423 bool requiresArrayCookie(const CXXNewExpr *expr) override;
424 CharUnits getArrayCookieSizeImpl(QualType type) override;
425 Address InitializeArrayCookie(CodeGenFunction &CGF,
427 llvm::Value *NumElements,
428 const CXXNewExpr *expr,
429 QualType ElementType) override;
430 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
432 CharUnits cookieSize) override;
434 friend struct MSRTTIBuilder;
436 bool isImageRelative() const {
437 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
440 // 5 routines for constructing the llvm types for MS RTTI structs.
441 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
442 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
443 TDTypeName += llvm::utostr(TypeInfoString.size());
444 llvm::StructType *&TypeDescriptorType =
445 TypeDescriptorTypeMap[TypeInfoString.size()];
446 if (TypeDescriptorType)
447 return TypeDescriptorType;
448 llvm::Type *FieldTypes[] = {
451 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
453 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
454 return TypeDescriptorType;
457 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
458 if (!isImageRelative())
463 llvm::StructType *getBaseClassDescriptorType() {
464 if (BaseClassDescriptorType)
465 return BaseClassDescriptorType;
466 llvm::Type *FieldTypes[] = {
467 getImageRelativeType(CGM.Int8PtrTy),
473 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
475 BaseClassDescriptorType = llvm::StructType::create(
476 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
477 return BaseClassDescriptorType;
480 llvm::StructType *getClassHierarchyDescriptorType() {
481 if (ClassHierarchyDescriptorType)
482 return ClassHierarchyDescriptorType;
483 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
484 ClassHierarchyDescriptorType = llvm::StructType::create(
485 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
486 llvm::Type *FieldTypes[] = {
490 getImageRelativeType(
491 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
493 ClassHierarchyDescriptorType->setBody(FieldTypes);
494 return ClassHierarchyDescriptorType;
497 llvm::StructType *getCompleteObjectLocatorType() {
498 if (CompleteObjectLocatorType)
499 return CompleteObjectLocatorType;
500 CompleteObjectLocatorType = llvm::StructType::create(
501 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
502 llvm::Type *FieldTypes[] = {
506 getImageRelativeType(CGM.Int8PtrTy),
507 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
508 getImageRelativeType(CompleteObjectLocatorType),
510 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
511 if (!isImageRelative())
512 FieldTypesRef = FieldTypesRef.drop_back();
513 CompleteObjectLocatorType->setBody(FieldTypesRef);
514 return CompleteObjectLocatorType;
517 llvm::GlobalVariable *getImageBase() {
518 StringRef Name = "__ImageBase";
519 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
522 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
524 llvm::GlobalValue::ExternalLinkage,
525 /*Initializer=*/nullptr, Name);
528 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
529 if (!isImageRelative())
532 if (PtrVal->isNullValue())
533 return llvm::Constant::getNullValue(CGM.IntTy);
535 llvm::Constant *ImageBaseAsInt =
536 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
537 llvm::Constant *PtrValAsInt =
538 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
539 llvm::Constant *Diff =
540 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
541 /*HasNUW=*/true, /*HasNSW=*/true);
542 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
546 MicrosoftMangleContext &getMangleContext() {
547 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
550 llvm::Constant *getZeroInt() {
551 return llvm::ConstantInt::get(CGM.IntTy, 0);
554 llvm::Constant *getAllOnesInt() {
555 return llvm::Constant::getAllOnesValue(CGM.IntTy);
558 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) override;
561 GetNullMemberPointerFields(const MemberPointerType *MPT,
562 llvm::SmallVectorImpl<llvm::Constant *> &fields);
564 /// \brief Shared code for virtual base adjustment. Returns the offset from
565 /// the vbptr to the virtual base. Optionally returns the address of the
567 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
569 llvm::Value *VBPtrOffset,
570 llvm::Value *VBTableOffset,
571 llvm::Value **VBPtr = nullptr);
573 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
576 int32_t VBTableOffset,
577 llvm::Value **VBPtr = nullptr) {
578 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
579 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
580 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
581 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
584 std::pair<Address, llvm::Value *>
585 performBaseAdjustment(CodeGenFunction &CGF, Address Value,
586 QualType SrcRecordTy);
588 /// \brief Performs a full virtual base adjustment. Used to dereference
589 /// pointers to members of virtual bases.
590 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
591 const CXXRecordDecl *RD, Address Base,
592 llvm::Value *VirtualBaseAdjustmentOffset,
593 llvm::Value *VBPtrOffset /* optional */);
595 /// \brief Emits a full member pointer with the fields common to data and
596 /// function member pointers.
597 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
598 bool IsMemberFunction,
599 const CXXRecordDecl *RD,
600 CharUnits NonVirtualBaseAdjustment,
601 unsigned VBTableIndex);
603 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
606 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
607 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
609 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
610 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
612 /// \brief Generate a thunk for calling a virtual member function MD.
613 llvm::Function *EmitVirtualMemPtrThunk(
614 const CXXMethodDecl *MD,
615 const MicrosoftVTableContext::MethodVFTableLocation &ML);
618 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
620 bool isZeroInitializable(const MemberPointerType *MPT) override;
622 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
623 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
624 return RD->hasAttr<MSInheritanceAttr>();
627 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
629 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
630 CharUnits offset) override;
631 llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override;
632 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
634 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
637 const MemberPointerType *MPT,
638 bool Inequality) override;
640 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
642 const MemberPointerType *MPT) override;
645 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
646 Address Base, llvm::Value *MemPtr,
647 const MemberPointerType *MPT) override;
649 llvm::Value *EmitNonNullMemberPointerConversion(
650 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
651 CastKind CK, CastExpr::path_const_iterator PathBegin,
652 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
653 CGBuilderTy &Builder);
655 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
657 llvm::Value *Src) override;
659 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
660 llvm::Constant *Src) override;
662 llvm::Constant *EmitMemberPointerConversion(
663 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
664 CastKind CK, CastExpr::path_const_iterator PathBegin,
665 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
668 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
669 Address This, llvm::Value *&ThisPtrForCall,
671 const MemberPointerType *MPT) override;
673 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
675 llvm::StructType *getCatchableTypeType() {
676 if (CatchableTypeType)
677 return CatchableTypeType;
678 llvm::Type *FieldTypes[] = {
680 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
681 CGM.IntTy, // NonVirtualAdjustment
682 CGM.IntTy, // OffsetToVBPtr
683 CGM.IntTy, // VBTableIndex
685 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
687 CatchableTypeType = llvm::StructType::create(
688 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
689 return CatchableTypeType;
692 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
693 llvm::StructType *&CatchableTypeArrayType =
694 CatchableTypeArrayTypeMap[NumEntries];
695 if (CatchableTypeArrayType)
696 return CatchableTypeArrayType;
698 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
699 CTATypeName += llvm::utostr(NumEntries);
701 getImageRelativeType(getCatchableTypeType()->getPointerTo());
702 llvm::Type *FieldTypes[] = {
703 CGM.IntTy, // NumEntries
704 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
706 CatchableTypeArrayType =
707 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
708 return CatchableTypeArrayType;
711 llvm::StructType *getThrowInfoType() {
713 return ThrowInfoType;
714 llvm::Type *FieldTypes[] = {
716 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
717 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
718 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
720 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
722 return ThrowInfoType;
725 llvm::Constant *getThrowFn() {
726 // _CxxThrowException is passed an exception object and a ThrowInfo object
727 // which describes the exception.
728 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
729 llvm::FunctionType *FTy =
730 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
731 auto *Fn = cast<llvm::Function>(
732 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
733 // _CxxThrowException is stdcall on 32-bit x86 platforms.
734 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
735 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
739 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
742 llvm::Constant *getCatchableType(QualType T,
743 uint32_t NVOffset = 0,
744 int32_t VBPtrOffset = -1,
745 uint32_t VBIndex = 0);
747 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
749 llvm::GlobalVariable *getThrowInfo(QualType T) override;
752 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
753 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
754 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
755 /// \brief All the vftables that have been referenced.
756 VFTablesMapTy VFTablesMap;
757 VTablesMapTy VTablesMap;
759 /// \brief This set holds the record decls we've deferred vtable emission for.
760 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
763 /// \brief All the vbtables which have been referenced.
764 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
766 /// Info on the global variable used to guard initialization of static locals.
767 /// The BitIndex field is only used for externally invisible declarations.
769 GuardInfo() : Guard(nullptr), BitIndex(0) {}
770 llvm::GlobalVariable *Guard;
774 /// Map from DeclContext to the current guard variable. We assume that the
775 /// AST is visited in source code order.
776 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
777 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
778 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
780 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
781 llvm::StructType *BaseClassDescriptorType;
782 llvm::StructType *ClassHierarchyDescriptorType;
783 llvm::StructType *CompleteObjectLocatorType;
785 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
787 llvm::StructType *CatchableTypeType;
788 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
789 llvm::StructType *ThrowInfoType;
794 CGCXXABI::RecordArgABI
795 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
796 switch (CGM.getTarget().getTriple().getArch()) {
798 // FIXME: Implement for other architectures.
801 case llvm::Triple::thumb:
802 // Use the simple Itanium rules for now.
803 // FIXME: This is incompatible with MSVC for arguments with a dtor and no
805 return !canCopyArgument(RD) ? RAA_Indirect : RAA_Default;
807 case llvm::Triple::x86:
808 // All record arguments are passed in memory on x86. Decide whether to
809 // construct the object directly in argument memory, or to construct the
810 // argument elsewhere and copy the bytes during the call.
812 // If C++ prohibits us from making a copy, construct the arguments directly
813 // into argument memory.
814 if (!canCopyArgument(RD))
815 return RAA_DirectInMemory;
817 // Otherwise, construct the argument into a temporary and copy the bytes
818 // into the outgoing argument memory.
821 case llvm::Triple::x86_64:
822 // Win64 passes objects with non-trivial copy ctors indirectly.
823 if (RD->hasNonTrivialCopyConstructor())
826 // If an object has a destructor, we'd really like to pass it indirectly
827 // because it allows us to elide copies. Unfortunately, MSVC makes that
828 // impossible for small types, which it will pass in a single register or
829 // stack slot. Most objects with dtors are large-ish, so handle that early.
830 // We can't call out all large objects as being indirect because there are
831 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
832 // how we pass large POD types.
833 if (RD->hasNonTrivialDestructor() &&
834 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
837 // If this is true, the implicit copy constructor that Sema would have
838 // created would not be deleted. FIXME: We should provide a more direct way
839 // for CodeGen to ask whether the constructor was deleted.
840 if (!RD->hasUserDeclaredCopyConstructor() &&
841 !RD->hasUserDeclaredMoveConstructor() &&
842 !RD->needsOverloadResolutionForMoveConstructor() &&
843 !RD->hasUserDeclaredMoveAssignment() &&
844 !RD->needsOverloadResolutionForMoveAssignment())
847 // Otherwise, Sema should have created an implicit copy constructor if
849 assert(!RD->needsImplicitCopyConstructor());
851 // We have to make sure the trivial copy constructor isn't deleted.
852 for (const CXXConstructorDecl *CD : RD->ctors()) {
853 if (CD->isCopyConstructor()) {
854 assert(CD->isTrivial());
855 // We had at least one undeleted trivial copy ctor. Return directly.
856 if (!CD->isDeleted())
861 // The trivial copy constructor was deleted. Return indirectly.
865 llvm_unreachable("invalid enum");
868 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
869 const CXXDeleteExpr *DE,
871 QualType ElementType,
872 const CXXDestructorDecl *Dtor) {
873 // FIXME: Provide a source location here even though there's no
874 // CXXMemberCallExpr for dtor call.
875 bool UseGlobalDelete = DE->isGlobalDelete();
876 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
877 llvm::Value *MDThis =
878 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
880 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
883 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
884 llvm::Value *Args[] = {
885 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
886 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
887 auto *Fn = getThrowFn();
889 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
891 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
895 struct CatchRetScope final : EHScopeStack::Cleanup {
896 llvm::CatchPadInst *CPI;
898 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
900 void Emit(CodeGenFunction &CGF, Flags flags) override {
901 llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
902 CGF.Builder.CreateCatchRet(CPI, BB);
908 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
909 const CXXCatchStmt *S) {
910 // In the MS ABI, the runtime handles the copy, and the catch handler is
911 // responsible for destruction.
912 VarDecl *CatchParam = S->getExceptionDecl();
913 llvm::BasicBlock *CatchPadBB = CGF.Builder.GetInsertBlock();
914 llvm::CatchPadInst *CPI =
915 cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
916 CGF.CurrentFuncletPad = CPI;
918 // If this is a catch-all or the catch parameter is unnamed, we don't need to
919 // emit an alloca to the object.
920 if (!CatchParam || !CatchParam->getDeclName()) {
921 CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
925 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
926 CPI->setArgOperand(2, var.getObjectAddress(CGF).getPointer());
927 CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
928 CGF.EmitAutoVarCleanups(var);
931 /// We need to perform a generic polymorphic operation (like a typeid
932 /// or a cast), which requires an object with a vfptr. Adjust the
933 /// address to point to an object with a vfptr.
934 std::pair<Address, llvm::Value *>
935 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, Address Value,
936 QualType SrcRecordTy) {
937 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
938 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
939 const ASTContext &Context = getContext();
941 // If the class itself has a vfptr, great. This check implicitly
942 // covers non-virtual base subobjects: a class with its own virtual
943 // functions would be a candidate to be a primary base.
944 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
945 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
947 // Okay, one of the vbases must have a vfptr, or else this isn't
948 // actually a polymorphic class.
949 const CXXRecordDecl *PolymorphicBase = nullptr;
950 for (auto &Base : SrcDecl->vbases()) {
951 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
952 if (Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr()) {
953 PolymorphicBase = BaseDecl;
957 assert(PolymorphicBase && "polymorphic class has no apparent vfptr?");
959 llvm::Value *Offset =
960 GetVirtualBaseClassOffset(CGF, Value, SrcDecl, PolymorphicBase);
961 llvm::Value *Ptr = CGF.Builder.CreateInBoundsGEP(Value.getPointer(), Offset);
962 CharUnits VBaseAlign =
963 CGF.CGM.getVBaseAlignment(Value.getAlignment(), SrcDecl, PolymorphicBase);
964 return std::make_pair(Address(Ptr, VBaseAlign), Offset);
967 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
968 QualType SrcRecordTy) {
969 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
971 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
974 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
975 llvm::Value *Argument) {
976 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
977 llvm::FunctionType *FTy =
978 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
979 llvm::Value *Args[] = {Argument};
980 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
981 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
984 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
985 llvm::CallSite Call =
986 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
987 Call.setDoesNotReturn();
988 CGF.Builder.CreateUnreachable();
991 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
992 QualType SrcRecordTy,
994 llvm::Type *StdTypeInfoPtrTy) {
995 std::tie(ThisPtr, std::ignore) =
996 performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
997 auto Typeid = emitRTtypeidCall(CGF, ThisPtr.getPointer()).getInstruction();
998 return CGF.Builder.CreateBitCast(Typeid, StdTypeInfoPtrTy);
1001 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
1002 QualType SrcRecordTy) {
1003 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
1005 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
1008 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
1009 CodeGenFunction &CGF, Address This, QualType SrcRecordTy,
1010 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
1011 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
1013 llvm::Value *SrcRTTI =
1014 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
1015 llvm::Value *DestRTTI =
1016 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
1018 llvm::Value *Offset;
1019 std::tie(This, Offset) = performBaseAdjustment(CGF, This, SrcRecordTy);
1020 llvm::Value *ThisPtr = This.getPointer();
1021 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
1023 // PVOID __RTDynamicCast(
1027 // PVOID TargetType,
1028 // BOOL isReference)
1029 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
1030 CGF.Int8PtrTy, CGF.Int32Ty};
1031 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
1032 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
1034 llvm::Value *Args[] = {
1035 ThisPtr, Offset, SrcRTTI, DestRTTI,
1036 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
1037 ThisPtr = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
1038 return CGF.Builder.CreateBitCast(ThisPtr, DestLTy);
1042 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, Address Value,
1043 QualType SrcRecordTy,
1045 std::tie(Value, std::ignore) = performBaseAdjustment(CGF, Value, SrcRecordTy);
1047 // PVOID __RTCastToVoid(
1049 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
1050 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
1051 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
1053 llvm::Value *Args[] = {Value.getPointer()};
1054 return CGF.EmitRuntimeCall(Function, Args);
1057 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
1061 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
1062 CodeGenFunction &CGF, Address This, const CXXRecordDecl *ClassDecl,
1063 const CXXRecordDecl *BaseClassDecl) {
1064 const ASTContext &Context = getContext();
1065 int64_t VBPtrChars =
1066 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
1067 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
1068 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
1069 CharUnits VBTableChars =
1071 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
1072 llvm::Value *VBTableOffset =
1073 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
1075 llvm::Value *VBPtrToNewBase =
1076 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
1078 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
1079 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
1082 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
1083 return isa<CXXConstructorDecl>(GD.getDecl());
1086 static bool isDeletingDtor(GlobalDecl GD) {
1087 return isa<CXXDestructorDecl>(GD.getDecl()) &&
1088 GD.getDtorType() == Dtor_Deleting;
1091 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
1092 return isDeletingDtor(GD);
1095 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
1096 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
1100 CharUnits Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType());
1101 if (FI.isInstanceMethod()) {
1102 // If it's an instance method, aggregates are always returned indirectly via
1103 // the second parameter.
1104 FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
1105 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
1107 } else if (!RD->isPOD()) {
1108 // If it's a free function, non-POD types are returned indirectly.
1109 FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
1113 // Otherwise, use the C ABI rules.
1118 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1119 const CXXRecordDecl *RD) {
1120 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1121 assert(IsMostDerivedClass &&
1122 "ctor for a class with virtual bases must have an implicit parameter");
1123 llvm::Value *IsCompleteObject =
1124 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1126 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1127 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1128 CGF.Builder.CreateCondBr(IsCompleteObject,
1129 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1131 CGF.EmitBlock(CallVbaseCtorsBB);
1133 // Fill in the vbtable pointers here.
1134 EmitVBPtrStores(CGF, RD);
1136 // CGF will put the base ctor calls in this basic block for us later.
1138 return SkipVbaseCtorsBB;
1142 MicrosoftCXXABI::EmitDtorCompleteObjectHandler(CodeGenFunction &CGF) {
1143 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1144 assert(IsMostDerivedClass &&
1145 "ctor for a class with virtual bases must have an implicit parameter");
1146 llvm::Value *IsCompleteObject =
1147 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1149 llvm::BasicBlock *CallVbaseDtorsBB = CGF.createBasicBlock("Dtor.dtor_vbases");
1150 llvm::BasicBlock *SkipVbaseDtorsBB = CGF.createBasicBlock("Dtor.skip_vbases");
1151 CGF.Builder.CreateCondBr(IsCompleteObject,
1152 CallVbaseDtorsBB, SkipVbaseDtorsBB);
1154 CGF.EmitBlock(CallVbaseDtorsBB);
1155 // CGF will put the base dtor calls in this basic block for us later.
1157 return SkipVbaseDtorsBB;
1160 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1161 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1162 // In most cases, an override for a vbase virtual method can adjust
1163 // the "this" parameter by applying a constant offset.
1164 // However, this is not enough while a constructor or a destructor of some
1165 // class X is being executed if all the following conditions are met:
1166 // - X has virtual bases, (1)
1167 // - X overrides a virtual method M of a vbase Y, (2)
1168 // - X itself is a vbase of the most derived class.
1170 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1171 // which holds the extra amount of "this" adjustment we must do when we use
1172 // the X vftables (i.e. during X ctor or dtor).
1173 // Outside the ctors and dtors, the values of vtorDisps are zero.
1175 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1176 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1177 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1178 CGBuilderTy &Builder = CGF.Builder;
1180 unsigned AS = getThisAddress(CGF).getAddressSpace();
1181 llvm::Value *Int8This = nullptr; // Initialize lazily.
1183 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1185 if (!I->second.hasVtorDisp())
1188 llvm::Value *VBaseOffset =
1189 GetVirtualBaseClassOffset(CGF, getThisAddress(CGF), RD, I->first);
1190 uint64_t ConstantVBaseOffset =
1191 Layout.getVBaseClassOffset(I->first).getQuantity();
1193 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1194 llvm::Value *VtorDispValue = Builder.CreateSub(
1195 VBaseOffset, llvm::ConstantInt::get(CGM.PtrDiffTy, ConstantVBaseOffset),
1197 VtorDispValue = Builder.CreateTruncOrBitCast(VtorDispValue, CGF.Int32Ty);
1200 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1201 CGF.Int8Ty->getPointerTo(AS));
1202 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1203 // vtorDisp is always the 32-bits before the vbase in the class layout.
1204 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1205 VtorDispPtr = Builder.CreateBitCast(
1206 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1208 Builder.CreateAlignedStore(VtorDispValue, VtorDispPtr,
1209 CharUnits::fromQuantity(4));
1213 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1214 const CXXMethodDecl *MD) {
1215 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1216 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1217 CallingConv ActualCallingConv =
1218 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1219 return ExpectedCallingConv == ActualCallingConv;
1222 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1223 // There's only one constructor type in this ABI.
1224 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1226 // Exported default constructors either have a simple call-site where they use
1227 // the typical calling convention and have a single 'this' pointer for an
1228 // argument -or- they get a wrapper function which appropriately thunks to the
1229 // real default constructor. This thunk is the default constructor closure.
1230 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1231 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1232 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1233 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1234 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1238 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1239 const CXXRecordDecl *RD) {
1240 Address This = getThisAddress(CGF);
1241 This = CGF.Builder.CreateElementBitCast(This, CGM.Int8Ty, "this.int8");
1242 const ASTContext &Context = getContext();
1243 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1245 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1246 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1247 const std::unique_ptr<VPtrInfo> &VBT = (*VBGlobals.VBTables)[I];
1248 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1249 const ASTRecordLayout &SubobjectLayout =
1250 Context.getASTRecordLayout(VBT->IntroducingObject);
1251 CharUnits Offs = VBT->NonVirtualOffset;
1252 Offs += SubobjectLayout.getVBPtrOffset();
1253 if (VBT->getVBaseWithVPtr())
1254 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1255 Address VBPtr = CGF.Builder.CreateConstInBoundsByteGEP(This, Offs);
1256 llvm::Value *GVPtr =
1257 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1258 VBPtr = CGF.Builder.CreateElementBitCast(VBPtr, GVPtr->getType(),
1259 "vbptr." + VBT->ObjectWithVPtr->getName());
1260 CGF.Builder.CreateStore(GVPtr, VBPtr);
1265 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1266 SmallVectorImpl<CanQualType> &ArgTys) {
1267 // TODO: 'for base' flag
1268 if (T == StructorType::Deleting) {
1269 // The scalar deleting destructor takes an implicit int parameter.
1270 ArgTys.push_back(getContext().IntTy);
1272 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1276 // All parameters are already in place except is_most_derived, which goes
1277 // after 'this' if it's variadic and last if it's not.
1279 const CXXRecordDecl *Class = CD->getParent();
1280 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1281 if (Class->getNumVBases()) {
1282 if (FPT->isVariadic())
1283 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1285 ArgTys.push_back(getContext().IntTy);
1289 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1290 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1291 // other destructor variants are delegating thunks.
1292 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1296 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1297 GD = GD.getCanonicalDecl();
1298 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1300 GlobalDecl LookupGD = GD;
1301 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1302 // Complete destructors take a pointer to the complete object as a
1303 // parameter, thus don't need this adjustment.
1304 if (GD.getDtorType() == Dtor_Complete)
1307 // There's no Dtor_Base in vftable but it shares the this adjustment with
1308 // the deleting one, so look it up instead.
1309 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1312 MicrosoftVTableContext::MethodVFTableLocation ML =
1313 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1314 CharUnits Adjustment = ML.VFPtrOffset;
1316 // Normal virtual instance methods need to adjust from the vfptr that first
1317 // defined the virtual method to the virtual base subobject, but destructors
1318 // do not. The vector deleting destructor thunk applies this adjustment for
1320 if (isa<CXXDestructorDecl>(MD))
1321 Adjustment = CharUnits::Zero();
1324 const ASTRecordLayout &DerivedLayout =
1325 getContext().getASTRecordLayout(MD->getParent());
1326 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1332 Address MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1333 CodeGenFunction &CGF, GlobalDecl GD, Address This,
1336 // If the call of a virtual function is not virtual, we just have to
1337 // compensate for the adjustment the virtual function does in its prologue.
1338 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1339 if (Adjustment.isZero())
1342 This = CGF.Builder.CreateElementBitCast(This, CGF.Int8Ty);
1343 assert(Adjustment.isPositive());
1344 return CGF.Builder.CreateConstByteGEP(This, Adjustment);
1347 GD = GD.getCanonicalDecl();
1348 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1350 GlobalDecl LookupGD = GD;
1351 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1352 // Complete dtors take a pointer to the complete object,
1353 // thus don't need adjustment.
1354 if (GD.getDtorType() == Dtor_Complete)
1357 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1358 // with the base one, so look up the deleting one instead.
1359 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1361 MicrosoftVTableContext::MethodVFTableLocation ML =
1362 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1364 CharUnits StaticOffset = ML.VFPtrOffset;
1366 // Base destructors expect 'this' to point to the beginning of the base
1367 // subobject, not the first vfptr that happens to contain the virtual dtor.
1368 // However, we still need to apply the virtual base adjustment.
1369 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1370 StaticOffset = CharUnits::Zero();
1372 Address Result = This;
1374 Result = CGF.Builder.CreateElementBitCast(Result, CGF.Int8Ty);
1376 const CXXRecordDecl *Derived = MD->getParent();
1377 const CXXRecordDecl *VBase = ML.VBase;
1378 llvm::Value *VBaseOffset =
1379 GetVirtualBaseClassOffset(CGF, Result, Derived, VBase);
1380 llvm::Value *VBasePtr =
1381 CGF.Builder.CreateInBoundsGEP(Result.getPointer(), VBaseOffset);
1382 CharUnits VBaseAlign =
1383 CGF.CGM.getVBaseAlignment(Result.getAlignment(), Derived, VBase);
1384 Result = Address(VBasePtr, VBaseAlign);
1386 if (!StaticOffset.isZero()) {
1387 assert(StaticOffset.isPositive());
1388 Result = CGF.Builder.CreateElementBitCast(Result, CGF.Int8Ty);
1390 // Non-virtual adjustment might result in a pointer outside the allocated
1391 // object, e.g. if the final overrider class is laid out after the virtual
1392 // base that declares a method in the most derived class.
1393 // FIXME: Update the code that emits this adjustment in thunks prologues.
1394 Result = CGF.Builder.CreateConstByteGEP(Result, StaticOffset);
1396 Result = CGF.Builder.CreateConstInBoundsByteGEP(Result, StaticOffset);
1402 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1404 FunctionArgList &Params) {
1405 ASTContext &Context = getContext();
1406 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1407 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1408 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1409 ImplicitParamDecl *IsMostDerived
1410 = ImplicitParamDecl::Create(Context, nullptr,
1411 CGF.CurGD.getDecl()->getLocation(),
1412 &Context.Idents.get("is_most_derived"),
1414 // The 'most_derived' parameter goes second if the ctor is variadic and last
1415 // if it's not. Dtors can't be variadic.
1416 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1417 if (FPT->isVariadic())
1418 Params.insert(Params.begin() + 1, IsMostDerived);
1420 Params.push_back(IsMostDerived);
1421 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1422 } else if (isDeletingDtor(CGF.CurGD)) {
1423 ImplicitParamDecl *ShouldDelete
1424 = ImplicitParamDecl::Create(Context, nullptr,
1425 CGF.CurGD.getDecl()->getLocation(),
1426 &Context.Idents.get("should_call_delete"),
1428 Params.push_back(ShouldDelete);
1429 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1433 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1434 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1435 // In this ABI, every virtual function takes a pointer to one of the
1436 // subobjects that first defines it as the 'this' parameter, rather than a
1437 // pointer to the final overrider subobject. Thus, we need to adjust it back
1438 // to the final overrider subobject before use.
1439 // See comments in the MicrosoftVFTableContext implementation for the details.
1440 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1441 if (Adjustment.isZero())
1444 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1445 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1446 *thisTy = This->getType();
1448 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1449 assert(Adjustment.isPositive());
1450 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1451 -Adjustment.getQuantity());
1452 return CGF.Builder.CreateBitCast(This, thisTy);
1455 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1456 // Naked functions have no prolog.
1457 if (CGF.CurFuncDecl && CGF.CurFuncDecl->hasAttr<NakedAttr>())
1462 /// If this is a function that the ABI specifies returns 'this', initialize
1463 /// the return slot to 'this' at the start of the function.
1465 /// Unlike the setting of return types, this is done within the ABI
1466 /// implementation instead of by clients of CGCXXABI because:
1467 /// 1) getThisValue is currently protected
1468 /// 2) in theory, an ABI could implement 'this' returns some other way;
1469 /// HasThisReturn only specifies a contract, not the implementation
1470 if (HasThisReturn(CGF.CurGD))
1471 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1472 else if (hasMostDerivedReturn(CGF.CurGD))
1473 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1476 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1477 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1478 assert(getStructorImplicitParamDecl(CGF) &&
1479 "no implicit parameter for a constructor with virtual bases?");
1480 getStructorImplicitParamValue(CGF)
1481 = CGF.Builder.CreateLoad(
1482 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1486 if (isDeletingDtor(CGF.CurGD)) {
1487 assert(getStructorImplicitParamDecl(CGF) &&
1488 "no implicit parameter for a deleting destructor?");
1489 getStructorImplicitParamValue(CGF)
1490 = CGF.Builder.CreateLoad(
1491 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1492 "should_call_delete");
1496 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1497 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1498 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1499 assert(Type == Ctor_Complete || Type == Ctor_Base);
1501 // Check if we need a 'most_derived' parameter.
1502 if (!D->getParent()->getNumVBases())
1505 // Add the 'most_derived' argument second if we are variadic or last if not.
1506 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1507 llvm::Value *MostDerivedArg;
1509 MostDerivedArg = getStructorImplicitParamValue(CGF);
1511 MostDerivedArg = llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1513 RValue RV = RValue::get(MostDerivedArg);
1514 if (FPT->isVariadic())
1515 Args.insert(Args.begin() + 1,
1516 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1518 Args.add(RV, getContext().IntTy);
1520 return 1; // Added one arg.
1523 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1524 const CXXDestructorDecl *DD,
1525 CXXDtorType Type, bool ForVirtualBase,
1526 bool Delegating, Address This) {
1527 CGCallee Callee = CGCallee::forDirect(
1528 CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type)),
1531 if (DD->isVirtual()) {
1532 assert(Type != CXXDtorType::Dtor_Deleting &&
1533 "The deleting destructor should only be called via a virtual call");
1534 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1538 llvm::BasicBlock *BaseDtorEndBB = nullptr;
1539 if (ForVirtualBase && isa<CXXConstructorDecl>(CGF.CurCodeDecl)) {
1540 BaseDtorEndBB = EmitDtorCompleteObjectHandler(CGF);
1543 CGF.EmitCXXDestructorCall(DD, Callee, This.getPointer(),
1544 /*ImplicitParam=*/nullptr,
1545 /*ImplicitParamTy=*/QualType(), nullptr,
1546 getFromDtorType(Type));
1547 if (BaseDtorEndBB) {
1548 // Complete object handler should continue to be the remaining
1549 CGF.Builder.CreateBr(BaseDtorEndBB);
1550 CGF.EmitBlock(BaseDtorEndBB);
1554 void MicrosoftCXXABI::emitVTableTypeMetadata(const VPtrInfo &Info,
1555 const CXXRecordDecl *RD,
1556 llvm::GlobalVariable *VTable) {
1557 if (!CGM.getCodeGenOpts().PrepareForLTO)
1560 // The location of the first virtual function pointer in the virtual table,
1561 // aka the "address point" on Itanium. This is at offset 0 if RTTI is
1562 // disabled, or sizeof(void*) if RTTI is enabled.
1563 CharUnits AddressPoint =
1564 getContext().getLangOpts().RTTIData
1565 ? getContext().toCharUnitsFromBits(
1566 getContext().getTargetInfo().getPointerWidth(0))
1567 : CharUnits::Zero();
1569 if (Info.PathToIntroducingObject.empty()) {
1570 CGM.AddVTableTypeMetadata(VTable, AddressPoint, RD);
1574 // Add a bitset entry for the least derived base belonging to this vftable.
1575 CGM.AddVTableTypeMetadata(VTable, AddressPoint,
1576 Info.PathToIntroducingObject.back());
1578 // Add a bitset entry for each derived class that is laid out at the same
1579 // offset as the least derived base.
1580 for (unsigned I = Info.PathToIntroducingObject.size() - 1; I != 0; --I) {
1581 const CXXRecordDecl *DerivedRD = Info.PathToIntroducingObject[I - 1];
1582 const CXXRecordDecl *BaseRD = Info.PathToIntroducingObject[I];
1584 const ASTRecordLayout &Layout =
1585 getContext().getASTRecordLayout(DerivedRD);
1587 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1588 if (VBI == Layout.getVBaseOffsetsMap().end())
1589 Offset = Layout.getBaseClassOffset(BaseRD);
1591 Offset = VBI->second.VBaseOffset;
1592 if (!Offset.isZero())
1594 CGM.AddVTableTypeMetadata(VTable, AddressPoint, DerivedRD);
1597 // Finally do the same for the most derived class.
1598 if (Info.FullOffsetInMDC.isZero())
1599 CGM.AddVTableTypeMetadata(VTable, AddressPoint, RD);
1602 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1603 const CXXRecordDecl *RD) {
1604 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1605 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1607 for (const std::unique_ptr<VPtrInfo>& Info : VFPtrs) {
1608 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1609 if (VTable->hasInitializer())
1612 const VTableLayout &VTLayout =
1613 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1615 llvm::Constant *RTTI = nullptr;
1616 if (any_of(VTLayout.vtable_components(),
1617 [](const VTableComponent &VTC) { return VTC.isRTTIKind(); }))
1618 RTTI = getMSCompleteObjectLocator(RD, *Info);
1620 ConstantInitBuilder Builder(CGM);
1621 auto Components = Builder.beginStruct();
1622 CGVT.createVTableInitializer(Components, VTLayout, RTTI);
1623 Components.finishAndSetAsInitializer(VTable);
1625 emitVTableTypeMetadata(*Info, RD, VTable);
1629 bool MicrosoftCXXABI::isVirtualOffsetNeededForVTableField(
1630 CodeGenFunction &CGF, CodeGenFunction::VPtr Vptr) {
1631 return Vptr.NearestVBase != nullptr;
1634 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1635 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1636 const CXXRecordDecl *NearestVBase) {
1637 llvm::Constant *VTableAddressPoint = getVTableAddressPoint(Base, VTableClass);
1638 if (!VTableAddressPoint) {
1639 assert(Base.getBase()->getNumVBases() &&
1640 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1642 return VTableAddressPoint;
1645 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1646 const CXXRecordDecl *RD, const VPtrInfo &VFPtr,
1647 SmallString<256> &Name) {
1648 llvm::raw_svector_ostream Out(Name);
1649 MangleContext.mangleCXXVFTable(RD, VFPtr.MangledPath, Out);
1653 MicrosoftCXXABI::getVTableAddressPoint(BaseSubobject Base,
1654 const CXXRecordDecl *VTableClass) {
1655 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1656 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1657 return VFTablesMap[ID];
1660 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1661 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1662 llvm::Constant *VFTable = getVTableAddressPoint(Base, VTableClass);
1663 assert(VFTable && "Couldn't find a vftable for the given base?");
1667 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1668 CharUnits VPtrOffset) {
1669 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1670 // shouldn't be used in the given record type. We want to cache this result in
1671 // VFTablesMap, thus a simple zero check is not sufficient.
1673 VFTableIdTy ID(RD, VPtrOffset);
1674 VTablesMapTy::iterator I;
1676 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1680 llvm::GlobalVariable *&VTable = I->second;
1682 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1683 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1685 if (DeferredVFTables.insert(RD).second) {
1686 // We haven't processed this record type before.
1687 // Queue up this vtable for possible deferred emission.
1688 CGM.addDeferredVTable(RD);
1691 // Create all the vftables at once in order to make sure each vftable has
1692 // a unique mangled name.
1693 llvm::StringSet<> ObservedMangledNames;
1694 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1695 SmallString<256> Name;
1696 mangleVFTableName(getMangleContext(), RD, *VFPtrs[J], Name);
1697 if (!ObservedMangledNames.insert(Name.str()).second)
1698 llvm_unreachable("Already saw this mangling before?");
1703 const std::unique_ptr<VPtrInfo> *VFPtrI = std::find_if(
1704 VFPtrs.begin(), VFPtrs.end(), [&](const std::unique_ptr<VPtrInfo>& VPI) {
1705 return VPI->FullOffsetInMDC == VPtrOffset;
1707 if (VFPtrI == VFPtrs.end()) {
1708 VFTablesMap[ID] = nullptr;
1711 const std::unique_ptr<VPtrInfo> &VFPtr = *VFPtrI;
1713 SmallString<256> VFTableName;
1714 mangleVFTableName(getMangleContext(), RD, *VFPtr, VFTableName);
1716 // Classes marked __declspec(dllimport) need vftables generated on the
1717 // import-side in order to support features like constexpr. No other
1718 // translation unit relies on the emission of the local vftable, translation
1719 // units are expected to generate them as needed.
1721 // Because of this unique behavior, we maintain this logic here instead of
1722 // getVTableLinkage.
1723 llvm::GlobalValue::LinkageTypes VFTableLinkage =
1724 RD->hasAttr<DLLImportAttr>() ? llvm::GlobalValue::LinkOnceODRLinkage
1725 : CGM.getVTableLinkage(RD);
1726 bool VFTableComesFromAnotherTU =
1727 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1728 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1729 bool VTableAliasIsRequred =
1730 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1732 if (llvm::GlobalValue *VFTable =
1733 CGM.getModule().getNamedGlobal(VFTableName)) {
1734 VFTablesMap[ID] = VFTable;
1735 VTable = VTableAliasIsRequred
1736 ? cast<llvm::GlobalVariable>(
1737 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1738 : cast<llvm::GlobalVariable>(VFTable);
1742 const VTableLayout &VTLayout =
1743 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC);
1744 llvm::GlobalValue::LinkageTypes VTableLinkage =
1745 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1747 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1749 llvm::Type *VTableType = CGM.getVTables().getVTableType(VTLayout);
1751 // Create a backing variable for the contents of VTable. The VTable may
1752 // or may not include space for a pointer to RTTI data.
1753 llvm::GlobalValue *VFTable;
1754 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1755 /*isConstant=*/true, VTableLinkage,
1756 /*Initializer=*/nullptr, VTableName);
1757 VTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1759 llvm::Comdat *C = nullptr;
1760 if (!VFTableComesFromAnotherTU &&
1761 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1762 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1763 VTableAliasIsRequred)))
1764 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1766 // Only insert a pointer into the VFTable for RTTI data if we are not
1767 // importing it. We never reference the RTTI data directly so there is no
1768 // need to make room for it.
1769 if (VTableAliasIsRequred) {
1770 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.Int32Ty, 0),
1771 llvm::ConstantInt::get(CGM.Int32Ty, 0),
1772 llvm::ConstantInt::get(CGM.Int32Ty, 1)};
1773 // Create a GEP which points just after the first entry in the VFTable,
1774 // this should be the location of the first virtual method.
1775 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1776 VTable->getValueType(), VTable, GEPIndices);
1777 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1778 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1780 C->setSelectionKind(llvm::Comdat::Largest);
1782 VFTable = llvm::GlobalAlias::create(CGM.Int8PtrTy,
1783 /*AddressSpace=*/0, VFTableLinkage,
1784 VFTableName.str(), VTableGEP,
1786 VFTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1788 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1789 // be referencing any RTTI data.
1790 // The GlobalVariable will end up being an appropriate definition of the
1795 VTable->setComdat(C);
1797 if (RD->hasAttr<DLLExportAttr>())
1798 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1800 VFTablesMap[ID] = VFTable;
1804 CGCallee MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1808 SourceLocation Loc) {
1809 GD = GD.getCanonicalDecl();
1810 CGBuilderTy &Builder = CGF.Builder;
1812 Ty = Ty->getPointerTo()->getPointerTo();
1814 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1816 auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl());
1817 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty, MethodDecl->getParent());
1819 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1820 MicrosoftVTableContext::MethodVFTableLocation ML =
1821 VFTContext.getMethodVFTableLocation(GD);
1823 // Compute the identity of the most derived class whose virtual table is
1824 // located at the MethodVFTableLocation ML.
1825 auto getObjectWithVPtr = [&] {
1826 return llvm::find_if(VFTContext.getVFPtrOffsets(
1827 ML.VBase ? ML.VBase : MethodDecl->getParent()),
1828 [&](const std::unique_ptr<VPtrInfo> &Info) {
1829 return Info->FullOffsetInMDC == ML.VFPtrOffset;
1836 if (CGF.ShouldEmitVTableTypeCheckedLoad(MethodDecl->getParent())) {
1837 VFunc = CGF.EmitVTableTypeCheckedLoad(
1838 getObjectWithVPtr(), VTable,
1839 ML.Index * CGM.getContext().getTargetInfo().getPointerWidth(0) / 8);
1841 if (CGM.getCodeGenOpts().PrepareForLTO)
1842 CGF.EmitTypeMetadataCodeForVCall(getObjectWithVPtr(), VTable, Loc);
1844 llvm::Value *VFuncPtr =
1845 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1846 VFunc = Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign());
1849 CGCallee Callee(MethodDecl, VFunc);
1853 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1854 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1855 Address This, const CXXMemberCallExpr *CE) {
1856 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1857 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1859 // We have only one destructor in the vftable but can get both behaviors
1860 // by passing an implicit int parameter.
1861 GlobalDecl GD(Dtor, Dtor_Deleting);
1862 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1863 Dtor, StructorType::Deleting);
1864 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1865 CGCallee Callee = getVirtualFunctionPointer(
1866 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1868 ASTContext &Context = getContext();
1869 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1870 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1871 DtorType == Dtor_Deleting);
1873 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1875 CGF.EmitCXXDestructorCall(Dtor, Callee, This.getPointer(), ImplicitParam,
1876 Context.IntTy, CE, StructorType::Deleting);
1877 return RV.getScalarVal();
1880 const VBTableGlobals &
1881 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1882 // At this layer, we can key the cache off of a single class, which is much
1883 // easier than caching each vbtable individually.
1884 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1886 std::tie(Entry, Added) =
1887 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1888 VBTableGlobals &VBGlobals = Entry->second;
1892 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1893 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1895 // Cache the globals for all vbtables so we don't have to recompute the
1897 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1898 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1899 E = VBGlobals.VBTables->end();
1901 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1907 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1908 const CXXMethodDecl *MD,
1909 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1910 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1911 "can't form pointers to ctors or virtual dtors");
1913 // Calculate the mangled name.
1914 SmallString<256> ThunkName;
1915 llvm::raw_svector_ostream Out(ThunkName);
1916 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1918 // If the thunk has been generated previously, just return it.
1919 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1920 return cast<llvm::Function>(GV);
1922 // Create the llvm::Function.
1923 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1924 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1925 llvm::Function *ThunkFn =
1926 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1927 ThunkName.str(), &CGM.getModule());
1928 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1930 ThunkFn->setLinkage(MD->isExternallyVisible()
1931 ? llvm::GlobalValue::LinkOnceODRLinkage
1932 : llvm::GlobalValue::InternalLinkage);
1933 if (MD->isExternallyVisible())
1934 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1936 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1937 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1939 // Add the "thunk" attribute so that LLVM knows that the return type is
1940 // meaningless. These thunks can be used to call functions with differing
1941 // return types, and the caller is required to cast the prototype
1942 // appropriately to extract the correct value.
1943 ThunkFn->addFnAttr("thunk");
1945 // These thunks can be compared, so they are not unnamed.
1946 ThunkFn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::None);
1949 CodeGenFunction CGF(CGM);
1950 CGF.CurGD = GlobalDecl(MD);
1951 CGF.CurFuncIsThunk = true;
1953 // Build FunctionArgs, but only include the implicit 'this' parameter
1955 FunctionArgList FunctionArgs;
1956 buildThisParam(CGF, FunctionArgs);
1958 // Start defining the function.
1959 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1960 FunctionArgs, MD->getLocation(), SourceLocation());
1963 // Load the vfptr and then callee from the vftable. The callee should have
1964 // adjusted 'this' so that the vfptr is at offset zero.
1965 llvm::Value *VTable = CGF.GetVTablePtr(
1966 getThisAddress(CGF), ThunkTy->getPointerTo()->getPointerTo(), MD->getParent());
1968 llvm::Value *VFuncPtr =
1969 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1970 llvm::Value *Callee =
1971 CGF.Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign());
1973 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1978 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1979 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1980 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1981 const std::unique_ptr<VPtrInfo>& VBT = (*VBGlobals.VBTables)[I];
1982 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1983 if (GV->isDeclaration())
1984 emitVBTableDefinition(*VBT, RD, GV);
1988 llvm::GlobalVariable *
1989 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1990 llvm::GlobalVariable::LinkageTypes Linkage) {
1991 SmallString<256> OutName;
1992 llvm::raw_svector_ostream Out(OutName);
1993 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1994 StringRef Name = OutName.str();
1996 llvm::ArrayType *VBTableType =
1997 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ObjectWithVPtr->getNumVBases());
1999 assert(!CGM.getModule().getNamedGlobal(Name) &&
2000 "vbtable with this name already exists: mangling bug?");
2001 llvm::GlobalVariable *GV =
2002 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
2003 GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2005 if (RD->hasAttr<DLLImportAttr>())
2006 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
2007 else if (RD->hasAttr<DLLExportAttr>())
2008 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
2010 if (!GV->hasExternalLinkage())
2011 emitVBTableDefinition(VBT, RD, GV);
2016 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
2017 const CXXRecordDecl *RD,
2018 llvm::GlobalVariable *GV) const {
2019 const CXXRecordDecl *ObjectWithVPtr = VBT.ObjectWithVPtr;
2021 assert(RD->getNumVBases() && ObjectWithVPtr->getNumVBases() &&
2022 "should only emit vbtables for classes with vbtables");
2024 const ASTRecordLayout &BaseLayout =
2025 getContext().getASTRecordLayout(VBT.IntroducingObject);
2026 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
2028 SmallVector<llvm::Constant *, 4> Offsets(1 + ObjectWithVPtr->getNumVBases(),
2031 // The offset from ObjectWithVPtr's vbptr to itself always leads.
2032 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
2033 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
2035 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
2036 for (const auto &I : ObjectWithVPtr->vbases()) {
2037 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
2038 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
2039 assert(!Offset.isNegative());
2041 // Make it relative to the subobject vbptr.
2042 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
2043 if (VBT.getVBaseWithVPtr())
2044 CompleteVBPtrOffset +=
2045 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
2046 Offset -= CompleteVBPtrOffset;
2048 unsigned VBIndex = Context.getVBTableIndex(ObjectWithVPtr, VBase);
2049 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
2050 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
2053 assert(Offsets.size() ==
2054 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
2055 ->getElementType())->getNumElements());
2056 llvm::ArrayType *VBTableType =
2057 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
2058 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
2059 GV->setInitializer(Init);
2061 if (RD->hasAttr<DLLImportAttr>())
2062 GV->setLinkage(llvm::GlobalVariable::AvailableExternallyLinkage);
2065 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
2067 const ThisAdjustment &TA) {
2069 return This.getPointer();
2071 This = CGF.Builder.CreateElementBitCast(This, CGF.Int8Ty);
2074 if (TA.Virtual.isEmpty()) {
2075 V = This.getPointer();
2077 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
2078 // Adjust the this argument based on the vtordisp value.
2079 Address VtorDispPtr =
2080 CGF.Builder.CreateConstInBoundsByteGEP(This,
2081 CharUnits::fromQuantity(TA.Virtual.Microsoft.VtordispOffset));
2082 VtorDispPtr = CGF.Builder.CreateElementBitCast(VtorDispPtr, CGF.Int32Ty);
2083 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
2084 V = CGF.Builder.CreateGEP(This.getPointer(),
2085 CGF.Builder.CreateNeg(VtorDisp));
2087 // Unfortunately, having applied the vtordisp means that we no
2088 // longer really have a known alignment for the vbptr step.
2089 // We'll assume the vbptr is pointer-aligned.
2091 if (TA.Virtual.Microsoft.VBPtrOffset) {
2092 // If the final overrider is defined in a virtual base other than the one
2093 // that holds the vfptr, we have to use a vtordispex thunk which looks up
2094 // the vbtable of the derived class.
2095 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
2096 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
2098 llvm::Value *VBaseOffset =
2099 GetVBaseOffsetFromVBPtr(CGF, Address(V, CGF.getPointerAlign()),
2100 -TA.Virtual.Microsoft.VBPtrOffset,
2101 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
2102 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2106 if (TA.NonVirtual) {
2107 // Non-virtual adjustment might result in a pointer outside the allocated
2108 // object, e.g. if the final overrider class is laid out after the virtual
2109 // base that declares a method in the most derived class.
2110 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
2113 // Don't need to bitcast back, the call CodeGen will handle this.
2118 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, Address Ret,
2119 const ReturnAdjustment &RA) {
2121 return Ret.getPointer();
2123 auto OrigTy = Ret.getType();
2124 Ret = CGF.Builder.CreateElementBitCast(Ret, CGF.Int8Ty);
2126 llvm::Value *V = Ret.getPointer();
2127 if (RA.Virtual.Microsoft.VBIndex) {
2128 assert(RA.Virtual.Microsoft.VBIndex > 0);
2129 int32_t IntSize = CGF.getIntSize().getQuantity();
2131 llvm::Value *VBaseOffset =
2132 GetVBaseOffsetFromVBPtr(CGF, Ret, RA.Virtual.Microsoft.VBPtrOffset,
2133 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
2134 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
2138 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
2140 // Cast back to the original type.
2141 return CGF.Builder.CreateBitCast(V, OrigTy);
2144 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
2145 QualType elementType) {
2146 // Microsoft seems to completely ignore the possibility of a
2147 // two-argument usual deallocation function.
2148 return elementType.isDestructedType();
2151 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
2152 // Microsoft seems to completely ignore the possibility of a
2153 // two-argument usual deallocation function.
2154 return expr->getAllocatedType().isDestructedType();
2157 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2158 // The array cookie is always a size_t; we then pad that out to the
2159 // alignment of the element type.
2160 ASTContext &Ctx = getContext();
2161 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2162 Ctx.getTypeAlignInChars(type));
2165 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2167 CharUnits cookieSize) {
2168 Address numElementsPtr =
2169 CGF.Builder.CreateElementBitCast(allocPtr, CGF.SizeTy);
2170 return CGF.Builder.CreateLoad(numElementsPtr);
2173 Address MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2175 llvm::Value *numElements,
2176 const CXXNewExpr *expr,
2177 QualType elementType) {
2178 assert(requiresArrayCookie(expr));
2180 // The size of the cookie.
2181 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2183 // Compute an offset to the cookie.
2184 Address cookiePtr = newPtr;
2186 // Write the number of elements into the appropriate slot.
2187 Address numElementsPtr
2188 = CGF.Builder.CreateElementBitCast(cookiePtr, CGF.SizeTy);
2189 CGF.Builder.CreateStore(numElements, numElementsPtr);
2191 // Finally, compute a pointer to the actual data buffer by skipping
2192 // over the cookie completely.
2193 return CGF.Builder.CreateConstInBoundsByteGEP(newPtr, cookieSize);
2196 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2197 llvm::Constant *Dtor,
2198 llvm::Constant *Addr) {
2199 // Create a function which calls the destructor.
2200 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2202 // extern "C" int __tlregdtor(void (*f)(void));
2203 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2204 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2206 llvm::Constant *TLRegDtor =
2207 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor",
2208 llvm::AttributeSet(), /*Local=*/true);
2209 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2210 TLRegDtorFn->setDoesNotThrow();
2212 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2215 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2216 llvm::Constant *Dtor,
2217 llvm::Constant *Addr) {
2219 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2221 // The default behavior is to use atexit.
2222 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2225 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2226 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
2227 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2228 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) {
2229 if (CXXThreadLocalInits.empty())
2232 CGM.AppendLinkerOptions(CGM.getTarget().getTriple().getArch() ==
2234 ? "/include:___dyn_tls_init@12"
2235 : "/include:__dyn_tls_init");
2237 // This will create a GV in the .CRT$XDU section. It will point to our
2238 // initialization function. The CRT will call all of these function
2239 // pointers at start-up time and, eventually, at thread-creation time.
2240 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2241 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2242 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2243 llvm::GlobalVariable::InternalLinkage, InitFunc,
2244 Twine(InitFunc->getName(), "$initializer$"));
2245 InitFuncPtr->setSection(".CRT$XDU");
2246 // This variable has discardable linkage, we have to add it to @llvm.used to
2247 // ensure it won't get discarded.
2248 CGM.addUsedGlobal(InitFuncPtr);
2252 std::vector<llvm::Function *> NonComdatInits;
2253 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2254 llvm::GlobalVariable *GV = cast<llvm::GlobalVariable>(
2255 CGM.GetGlobalValue(CGM.getMangledName(CXXThreadLocalInitVars[I])));
2256 llvm::Function *F = CXXThreadLocalInits[I];
2258 // If the GV is already in a comdat group, then we have to join it.
2259 if (llvm::Comdat *C = GV->getComdat())
2260 AddToXDU(F)->setComdat(C);
2262 NonComdatInits.push_back(F);
2265 if (!NonComdatInits.empty()) {
2266 llvm::FunctionType *FTy =
2267 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2268 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2269 FTy, "__tls_init", CGM.getTypes().arrangeNullaryFunction(),
2270 SourceLocation(), /*TLS=*/true);
2271 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2277 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2279 QualType LValType) {
2280 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2284 static ConstantAddress getInitThreadEpochPtr(CodeGenModule &CGM) {
2285 StringRef VarName("_Init_thread_epoch");
2286 CharUnits Align = CGM.getIntAlign();
2287 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2288 return ConstantAddress(GV, Align);
2289 auto *GV = new llvm::GlobalVariable(
2290 CGM.getModule(), CGM.IntTy,
2291 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2292 /*Initializer=*/nullptr, VarName,
2293 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2294 GV->setAlignment(Align.getQuantity());
2295 return ConstantAddress(GV, Align);
2298 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2299 llvm::FunctionType *FTy =
2300 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2301 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2302 return CGM.CreateRuntimeFunction(
2303 FTy, "_Init_thread_header",
2304 llvm::AttributeSet::get(CGM.getLLVMContext(),
2305 llvm::AttributeSet::FunctionIndex,
2306 llvm::Attribute::NoUnwind),
2310 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2311 llvm::FunctionType *FTy =
2312 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2313 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2314 return CGM.CreateRuntimeFunction(
2315 FTy, "_Init_thread_footer",
2316 llvm::AttributeSet::get(CGM.getLLVMContext(),
2317 llvm::AttributeSet::FunctionIndex,
2318 llvm::Attribute::NoUnwind),
2322 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2323 llvm::FunctionType *FTy =
2324 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2325 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2326 return CGM.CreateRuntimeFunction(
2327 FTy, "_Init_thread_abort",
2328 llvm::AttributeSet::get(CGM.getLLVMContext(),
2329 llvm::AttributeSet::FunctionIndex,
2330 llvm::Attribute::NoUnwind),
2335 struct ResetGuardBit final : EHScopeStack::Cleanup {
2338 ResetGuardBit(Address Guard, unsigned GuardNum)
2339 : Guard(Guard), GuardNum(GuardNum) {}
2341 void Emit(CodeGenFunction &CGF, Flags flags) override {
2342 // Reset the bit in the mask so that the static variable may be
2344 CGBuilderTy &Builder = CGF.Builder;
2345 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2346 llvm::ConstantInt *Mask =
2347 llvm::ConstantInt::get(CGF.IntTy, ~(1ULL << GuardNum));
2348 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2352 struct CallInitThreadAbort final : EHScopeStack::Cleanup {
2354 CallInitThreadAbort(Address Guard) : Guard(Guard.getPointer()) {}
2356 void Emit(CodeGenFunction &CGF, Flags flags) override {
2357 // Calling _Init_thread_abort will reset the guard's state.
2358 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2363 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2364 llvm::GlobalVariable *GV,
2366 // MSVC only uses guards for static locals.
2367 if (!D.isStaticLocal()) {
2368 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2369 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2370 llvm::Function *F = CGF.CurFn;
2371 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2372 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2373 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2377 bool ThreadlocalStatic = D.getTLSKind();
2378 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2380 // Thread-safe static variables which aren't thread-specific have a
2381 // per-variable guard.
2382 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2384 CGBuilderTy &Builder = CGF.Builder;
2385 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2386 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2387 CharUnits GuardAlign = CharUnits::fromQuantity(4);
2389 // Get the guard variable for this function if we have one already.
2390 GuardInfo *GI = nullptr;
2391 if (ThreadlocalStatic)
2392 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2393 else if (!ThreadsafeStatic)
2394 GI = &GuardVariableMap[D.getDeclContext()];
2396 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2398 if (D.isExternallyVisible()) {
2399 // Externally visible variables have to be numbered in Sema to properly
2400 // handle unreachable VarDecls.
2401 GuardNum = getContext().getStaticLocalNumber(&D);
2402 assert(GuardNum > 0);
2404 } else if (HasPerVariableGuard) {
2405 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2407 // Non-externally visible variables are numbered here in CodeGen.
2408 GuardNum = GI->BitIndex++;
2411 if (!HasPerVariableGuard && GuardNum >= 32) {
2412 if (D.isExternallyVisible())
2413 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2419 // Mangle the name for the guard.
2420 SmallString<256> GuardName;
2422 llvm::raw_svector_ostream Out(GuardName);
2423 if (HasPerVariableGuard)
2424 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2427 getMangleContext().mangleStaticGuardVariable(&D, Out);
2430 // Create the guard variable with a zero-initializer. Just absorb linkage,
2431 // visibility and dll storage class from the guarded variable.
2433 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2434 GV->getLinkage(), Zero, GuardName.str());
2435 GuardVar->setVisibility(GV->getVisibility());
2436 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2437 GuardVar->setAlignment(GuardAlign.getQuantity());
2438 if (GuardVar->isWeakForLinker())
2439 GuardVar->setComdat(
2440 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2442 GuardVar->setThreadLocal(true);
2443 if (GI && !HasPerVariableGuard)
2444 GI->Guard = GuardVar;
2447 ConstantAddress GuardAddr(GuardVar, GuardAlign);
2449 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2450 "static local from the same function had different linkage");
2452 if (!HasPerVariableGuard) {
2453 // Pseudo code for the test:
2454 // if (!(GuardVar & MyGuardBit)) {
2455 // GuardVar |= MyGuardBit;
2456 // ... initialize the object ...;
2459 // Test our bit from the guard variable.
2460 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1ULL << GuardNum);
2461 llvm::LoadInst *LI = Builder.CreateLoad(GuardAddr);
2462 llvm::Value *IsInitialized =
2463 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2464 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2465 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2466 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2468 // Set our bit in the guard variable and emit the initializer and add a global
2469 // destructor if appropriate.
2470 CGF.EmitBlock(InitBlock);
2471 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardAddr);
2472 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardAddr, GuardNum);
2473 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2474 CGF.PopCleanupBlock();
2475 Builder.CreateBr(EndBlock);
2478 CGF.EmitBlock(EndBlock);
2480 // Pseudo code for the test:
2481 // if (TSS > _Init_thread_epoch) {
2482 // _Init_thread_header(&TSS);
2484 // ... initialize the object ...;
2485 // _Init_thread_footer(&TSS);
2489 // The algorithm is almost identical to what can be found in the appendix
2492 // This BasicBLock determines whether or not we have any work to do.
2493 llvm::LoadInst *FirstGuardLoad = Builder.CreateLoad(GuardAddr);
2494 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2495 llvm::LoadInst *InitThreadEpoch =
2496 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2497 llvm::Value *IsUninitialized =
2498 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2499 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2500 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2501 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2503 // This BasicBlock attempts to determine whether or not this thread is
2504 // responsible for doing the initialization.
2505 CGF.EmitBlock(AttemptInitBlock);
2506 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM),
2507 GuardAddr.getPointer());
2508 llvm::LoadInst *SecondGuardLoad = Builder.CreateLoad(GuardAddr);
2509 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2510 llvm::Value *ShouldDoInit =
2511 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2512 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2513 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2515 // Ok, we ended up getting selected as the initializing thread.
2516 CGF.EmitBlock(InitBlock);
2517 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardAddr);
2518 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2519 CGF.PopCleanupBlock();
2520 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM),
2521 GuardAddr.getPointer());
2522 Builder.CreateBr(EndBlock);
2524 CGF.EmitBlock(EndBlock);
2528 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2529 // Null-ness for function memptrs only depends on the first field, which is
2530 // the function pointer. The rest don't matter, so we can zero initialize.
2531 if (MPT->isMemberFunctionPointer())
2534 // The virtual base adjustment field is always -1 for null, so if we have one
2535 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2536 // valid field offset.
2537 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2538 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2539 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2540 RD->nullFieldOffsetIsZero());
2544 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2545 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2546 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2547 llvm::SmallVector<llvm::Type *, 4> fields;
2548 if (MPT->isMemberFunctionPointer())
2549 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2551 fields.push_back(CGM.IntTy); // FieldOffset
2553 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2555 fields.push_back(CGM.IntTy);
2556 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2557 fields.push_back(CGM.IntTy);
2558 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2559 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2561 if (fields.size() == 1)
2563 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2566 void MicrosoftCXXABI::
2567 GetNullMemberPointerFields(const MemberPointerType *MPT,
2568 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2569 assert(fields.empty());
2570 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2571 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2572 if (MPT->isMemberFunctionPointer()) {
2573 // FunctionPointerOrVirtualThunk
2574 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2576 if (RD->nullFieldOffsetIsZero())
2577 fields.push_back(getZeroInt()); // FieldOffset
2579 fields.push_back(getAllOnesInt()); // FieldOffset
2582 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2584 fields.push_back(getZeroInt());
2585 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2586 fields.push_back(getZeroInt());
2587 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2588 fields.push_back(getAllOnesInt());
2592 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2593 llvm::SmallVector<llvm::Constant *, 4> fields;
2594 GetNullMemberPointerFields(MPT, fields);
2595 if (fields.size() == 1)
2597 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2598 assert(Res->getType() == ConvertMemberPointerType(MPT));
2603 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2604 bool IsMemberFunction,
2605 const CXXRecordDecl *RD,
2606 CharUnits NonVirtualBaseAdjustment,
2607 unsigned VBTableIndex) {
2608 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2610 // Single inheritance class member pointer are represented as scalars instead
2612 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2615 llvm::SmallVector<llvm::Constant *, 4> fields;
2616 fields.push_back(FirstField);
2618 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2619 fields.push_back(llvm::ConstantInt::get(
2620 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2622 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2623 CharUnits Offs = CharUnits::Zero();
2625 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2626 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2629 // The rest of the fields are adjusted by conversions to a more derived class.
2630 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2631 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2633 return llvm::ConstantStruct::getAnon(fields);
2637 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2639 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2640 if (RD->getMSInheritanceModel() ==
2641 MSInheritanceAttr::Keyword_virtual_inheritance)
2642 offset -= getContext().getOffsetOfBaseWithVBPtr(RD);
2643 llvm::Constant *FirstField =
2644 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2645 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2646 CharUnits::Zero(), /*VBTableIndex=*/0);
2649 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2651 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2652 const ValueDecl *MPD = MP.getMemberPointerDecl();
2654 return EmitNullMemberPointer(DstTy);
2656 ASTContext &Ctx = getContext();
2657 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2660 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2661 C = EmitMemberFunctionPointer(MD);
2663 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2664 C = EmitMemberDataPointer(DstTy, FieldOffset);
2667 if (!MemberPointerPath.empty()) {
2668 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2669 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2670 const MemberPointerType *SrcTy =
2671 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2672 ->castAs<MemberPointerType>();
2674 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2675 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2676 const CXXRecordDecl *PrevRD = SrcRD;
2677 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2678 const CXXRecordDecl *Base = nullptr;
2679 const CXXRecordDecl *Derived = nullptr;
2680 if (DerivedMember) {
2687 for (const CXXBaseSpecifier &BS : Derived->bases())
2688 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2689 Base->getCanonicalDecl())
2690 DerivedToBasePath.push_back(&BS);
2693 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2695 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2696 : CK_BaseToDerivedMemberPointer;
2697 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2698 DerivedToBasePath.end(), C);
2704 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2705 assert(MD->isInstance() && "Member function must not be static!");
2707 MD = MD->getCanonicalDecl();
2708 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2709 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2710 CodeGenTypes &Types = CGM.getTypes();
2712 unsigned VBTableIndex = 0;
2713 llvm::Constant *FirstField;
2714 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2715 if (!MD->isVirtual()) {
2717 // Check whether the function has a computable LLVM signature.
2718 if (Types.isFuncTypeConvertible(FPT)) {
2719 // The function has a computable LLVM signature; use the correct type.
2720 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2722 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2723 // function type is incomplete.
2726 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2728 auto &VTableContext = CGM.getMicrosoftVTableContext();
2729 MicrosoftVTableContext::MethodVFTableLocation ML =
2730 VTableContext.getMethodVFTableLocation(MD);
2731 FirstField = EmitVirtualMemPtrThunk(MD, ML);
2732 // Include the vfptr adjustment if the method is in a non-primary vftable.
2733 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2735 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2738 if (VBTableIndex == 0 &&
2739 RD->getMSInheritanceModel() ==
2740 MSInheritanceAttr::Keyword_virtual_inheritance)
2741 NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD);
2743 // The rest of the fields are common with data member pointers.
2744 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2745 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2746 NonVirtualBaseAdjustment, VBTableIndex);
2749 /// Member pointers are the same if they're either bitwise identical *or* both
2750 /// null. Null-ness for function members is determined by the first field,
2751 /// while for data member pointers we must compare all fields.
2753 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2756 const MemberPointerType *MPT,
2758 CGBuilderTy &Builder = CGF.Builder;
2760 // Handle != comparisons by switching the sense of all boolean operations.
2761 llvm::ICmpInst::Predicate Eq;
2762 llvm::Instruction::BinaryOps And, Or;
2764 Eq = llvm::ICmpInst::ICMP_NE;
2765 And = llvm::Instruction::Or;
2766 Or = llvm::Instruction::And;
2768 Eq = llvm::ICmpInst::ICMP_EQ;
2769 And = llvm::Instruction::And;
2770 Or = llvm::Instruction::Or;
2773 // If this is a single field member pointer (single inheritance), this is a
2775 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2776 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2777 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2779 return Builder.CreateICmp(Eq, L, R);
2781 // Compare the first field.
2782 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2783 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2784 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2786 // Compare everything other than the first field.
2787 llvm::Value *Res = nullptr;
2788 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2789 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2790 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2791 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2792 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2794 Res = Builder.CreateBinOp(And, Res, Cmp);
2799 // Check if the first field is 0 if this is a function pointer.
2800 if (MPT->isMemberFunctionPointer()) {
2801 // (l1 == r1 && ...) || l0 == 0
2802 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2803 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2804 Res = Builder.CreateBinOp(Or, Res, IsZero);
2807 // Combine the comparison of the first field, which must always be true for
2808 // this comparison to succeeed.
2809 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2813 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2814 llvm::Value *MemPtr,
2815 const MemberPointerType *MPT) {
2816 CGBuilderTy &Builder = CGF.Builder;
2817 llvm::SmallVector<llvm::Constant *, 4> fields;
2818 // We only need one field for member functions.
2819 if (MPT->isMemberFunctionPointer())
2820 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2822 GetNullMemberPointerFields(MPT, fields);
2823 assert(!fields.empty());
2824 llvm::Value *FirstField = MemPtr;
2825 if (MemPtr->getType()->isStructTy())
2826 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2827 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2829 // For function member pointers, we only need to test the function pointer
2830 // field. The other fields if any can be garbage.
2831 if (MPT->isMemberFunctionPointer())
2834 // Otherwise, emit a series of compares and combine the results.
2835 for (int I = 1, E = fields.size(); I < E; ++I) {
2836 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2837 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2838 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2843 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2844 llvm::Constant *Val) {
2845 // Function pointers are null if the pointer in the first field is null.
2846 if (MPT->isMemberFunctionPointer()) {
2847 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2848 Val->getAggregateElement(0U) : Val;
2849 return FirstField->isNullValue();
2852 // If it's not a function pointer and it's zero initializable, we can easily
2854 if (isZeroInitializable(MPT) && Val->isNullValue())
2857 // Otherwise, break down all the fields for comparison. Hopefully these
2858 // little Constants are reused, while a big null struct might not be.
2859 llvm::SmallVector<llvm::Constant *, 4> Fields;
2860 GetNullMemberPointerFields(MPT, Fields);
2861 if (Fields.size() == 1) {
2862 assert(Val->getType()->isIntegerTy());
2863 return Val == Fields[0];
2867 for (I = 0, E = Fields.size(); I != E; ++I) {
2868 if (Val->getAggregateElement(I) != Fields[I])
2875 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2877 llvm::Value *VBPtrOffset,
2878 llvm::Value *VBTableOffset,
2879 llvm::Value **VBPtrOut) {
2880 CGBuilderTy &Builder = CGF.Builder;
2881 // Load the vbtable pointer from the vbptr in the instance.
2882 This = Builder.CreateElementBitCast(This, CGM.Int8Ty);
2883 llvm::Value *VBPtr =
2884 Builder.CreateInBoundsGEP(This.getPointer(), VBPtrOffset, "vbptr");
2885 if (VBPtrOut) *VBPtrOut = VBPtr;
2886 VBPtr = Builder.CreateBitCast(VBPtr,
2887 CGM.Int32Ty->getPointerTo(0)->getPointerTo(This.getAddressSpace()));
2889 CharUnits VBPtrAlign;
2890 if (auto CI = dyn_cast<llvm::ConstantInt>(VBPtrOffset)) {
2891 VBPtrAlign = This.getAlignment().alignmentAtOffset(
2892 CharUnits::fromQuantity(CI->getSExtValue()));
2894 VBPtrAlign = CGF.getPointerAlign();
2897 llvm::Value *VBTable = Builder.CreateAlignedLoad(VBPtr, VBPtrAlign, "vbtable");
2899 // Translate from byte offset to table index. It improves analyzability.
2900 llvm::Value *VBTableIndex = Builder.CreateAShr(
2901 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2902 "vbtindex", /*isExact=*/true);
2904 // Load an i32 offset from the vb-table.
2905 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2906 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2907 return Builder.CreateAlignedLoad(VBaseOffs, CharUnits::fromQuantity(4),
2911 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2913 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2914 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2915 Address Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2916 CGBuilderTy &Builder = CGF.Builder;
2917 Base = Builder.CreateElementBitCast(Base, CGM.Int8Ty);
2918 llvm::BasicBlock *OriginalBB = nullptr;
2919 llvm::BasicBlock *SkipAdjustBB = nullptr;
2920 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2922 // In the unspecified inheritance model, there might not be a vbtable at all,
2923 // in which case we need to skip the virtual base lookup. If there is a
2924 // vbtable, the first entry is a no-op entry that gives back the original
2925 // base, so look for a virtual base adjustment offset of zero.
2927 OriginalBB = Builder.GetInsertBlock();
2928 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2929 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2930 llvm::Value *IsVirtual =
2931 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2933 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2934 CGF.EmitBlock(VBaseAdjustBB);
2937 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2938 // know the vbptr offset.
2940 CharUnits offs = CharUnits::Zero();
2941 if (!RD->hasDefinition()) {
2942 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2943 unsigned DiagID = Diags.getCustomDiagID(
2944 DiagnosticsEngine::Error,
2945 "member pointer representation requires a "
2946 "complete class type for %0 to perform this expression");
2947 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2948 } else if (RD->getNumVBases())
2949 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2950 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2952 llvm::Value *VBPtr = nullptr;
2953 llvm::Value *VBaseOffs =
2954 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2955 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2957 // Merge control flow with the case where we didn't have to adjust.
2958 if (VBaseAdjustBB) {
2959 Builder.CreateBr(SkipAdjustBB);
2960 CGF.EmitBlock(SkipAdjustBB);
2961 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2962 Phi->addIncoming(Base.getPointer(), OriginalBB);
2963 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2966 return AdjustedBase;
2969 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2970 CodeGenFunction &CGF, const Expr *E, Address Base, llvm::Value *MemPtr,
2971 const MemberPointerType *MPT) {
2972 assert(MPT->isMemberDataPointer());
2973 unsigned AS = Base.getAddressSpace();
2975 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2976 CGBuilderTy &Builder = CGF.Builder;
2977 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2978 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2980 // Extract the fields we need, regardless of model. We'll apply them if we
2982 llvm::Value *FieldOffset = MemPtr;
2983 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2984 llvm::Value *VBPtrOffset = nullptr;
2985 if (MemPtr->getType()->isStructTy()) {
2986 // We need to extract values.
2988 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2989 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2990 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2991 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2992 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2996 if (VirtualBaseAdjustmentOffset) {
2997 Addr = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
3000 Addr = Base.getPointer();
3004 Addr = Builder.CreateBitCast(Addr, CGF.Int8Ty->getPointerTo(AS));
3006 // Apply the offset, which we assume is non-null.
3007 Addr = Builder.CreateInBoundsGEP(Addr, FieldOffset, "memptr.offset");
3009 // Cast the address to the appropriate pointer type, adopting the address
3010 // space of the base pointer.
3011 return Builder.CreateBitCast(Addr, PType);
3015 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
3018 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
3019 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
3020 E->getCastKind() == CK_ReinterpretMemberPointer);
3022 // Use constant emission if we can.
3023 if (isa<llvm::Constant>(Src))
3024 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
3026 // We may be adding or dropping fields from the member pointer, so we need
3027 // both types and the inheritance models of both records.
3028 const MemberPointerType *SrcTy =
3029 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3030 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3031 bool IsFunc = SrcTy->isMemberFunctionPointer();
3033 // If the classes use the same null representation, reinterpret_cast is a nop.
3034 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
3035 if (IsReinterpret && IsFunc)
3038 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
3039 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
3040 if (IsReinterpret &&
3041 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
3044 CGBuilderTy &Builder = CGF.Builder;
3046 // Branch past the conversion if Src is null.
3047 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
3048 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
3050 // C++ 5.2.10p9: The null member pointer value is converted to the null member
3051 // pointer value of the destination type.
3052 if (IsReinterpret) {
3053 // For reinterpret casts, sema ensures that src and dst are both functions
3054 // or data and have the same size, which means the LLVM types should match.
3055 assert(Src->getType() == DstNull->getType());
3056 return Builder.CreateSelect(IsNotNull, Src, DstNull);
3059 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
3060 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
3061 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
3062 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
3063 CGF.EmitBlock(ConvertBB);
3065 llvm::Value *Dst = EmitNonNullMemberPointerConversion(
3066 SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src,
3069 Builder.CreateBr(ContinueBB);
3071 // In the continuation, choose between DstNull and Dst.
3072 CGF.EmitBlock(ContinueBB);
3073 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
3074 Phi->addIncoming(DstNull, OriginalBB);
3075 Phi->addIncoming(Dst, ConvertBB);
3079 llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion(
3080 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3081 CastExpr::path_const_iterator PathBegin,
3082 CastExpr::path_const_iterator PathEnd, llvm::Value *Src,
3083 CGBuilderTy &Builder) {
3084 const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
3085 const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
3086 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
3087 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
3088 bool IsFunc = SrcTy->isMemberFunctionPointer();
3089 bool IsConstant = isa<llvm::Constant>(Src);
3092 llvm::Value *FirstField = Src;
3093 llvm::Value *NonVirtualBaseAdjustment = getZeroInt();
3094 llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt();
3095 llvm::Value *VBPtrOffset = getZeroInt();
3096 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
3097 // We need to extract values.
3099 FirstField = Builder.CreateExtractValue(Src, I++);
3100 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
3101 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
3102 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
3103 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
3104 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
3105 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
3108 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
3109 const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy;
3110 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
3112 // For data pointers, we adjust the field offset directly. For functions, we
3113 // have a separate field.
3114 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
3116 // The virtual inheritance model has a quirk: the virtual base table is always
3117 // referenced when dereferencing a member pointer even if the member pointer
3118 // is non-virtual. This is accounted for by adjusting the non-virtual offset
3119 // to point backwards to the top of the MDC from the first VBase. Undo this
3120 // adjustment to normalize the member pointer.
3121 llvm::Value *SrcVBIndexEqZero =
3122 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3123 if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3124 if (int64_t SrcOffsetToFirstVBase =
3125 getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) {
3126 llvm::Value *UndoSrcAdjustment = Builder.CreateSelect(
3128 llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase),
3130 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment);
3134 // A non-zero vbindex implies that we are dealing with a source member in a
3135 // floating virtual base in addition to some non-virtual offset. If the
3136 // vbindex is zero, we are dealing with a source that exists in a non-virtual,
3137 // fixed, base. The difference between these two cases is that the vbindex +
3138 // nvoffset *always* point to the member regardless of what context they are
3139 // evaluated in so long as the vbindex is adjusted. A member inside a fixed
3140 // base requires explicit nv adjustment.
3141 llvm::Constant *BaseClassOffset = llvm::ConstantInt::get(
3143 CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd)
3146 llvm::Value *NVDisp;
3147 if (IsDerivedToBase)
3148 NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj");
3150 NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj");
3152 NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt());
3154 // Update the vbindex to an appropriate value in the destination because
3155 // SrcRD's vbtable might not be a strict prefix of the one in DstRD.
3156 llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero;
3157 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) &&
3158 MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) {
3159 if (llvm::GlobalVariable *VDispMap =
3160 getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) {
3161 llvm::Value *VBIndex = Builder.CreateExactUDiv(
3162 VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4));
3164 llvm::Constant *Mapping = VDispMap->getInitializer();
3165 VirtualBaseAdjustmentOffset =
3166 Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex));
3168 llvm::Value *Idxs[] = {getZeroInt(), VBIndex};
3169 VirtualBaseAdjustmentOffset =
3170 Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs),
3171 CharUnits::fromQuantity(4));
3175 Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt());
3179 // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize
3180 // it to the offset of the vbptr.
3181 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) {
3182 llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get(
3184 getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity());
3186 Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset);
3189 // Likewise, apply a similar adjustment so that dereferencing the member
3190 // pointer correctly accounts for the distance between the start of the first
3191 // virtual base and the top of the MDC.
3192 if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) {
3193 if (int64_t DstOffsetToFirstVBase =
3194 getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) {
3195 llvm::Value *DoDstAdjustment = Builder.CreateSelect(
3197 llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase),
3199 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment);
3203 // Recompose dst from the null struct and the adjusted fields from src.
3205 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
3208 Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy));
3210 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
3211 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3212 Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++);
3213 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3214 Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++);
3215 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3216 Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++);
3222 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
3223 llvm::Constant *Src) {
3224 const MemberPointerType *SrcTy =
3225 E->getSubExpr()->getType()->castAs<MemberPointerType>();
3226 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
3228 CastKind CK = E->getCastKind();
3230 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
3231 E->path_end(), Src);
3234 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
3235 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
3236 CastExpr::path_const_iterator PathBegin,
3237 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
3238 assert(CK == CK_DerivedToBaseMemberPointer ||
3239 CK == CK_BaseToDerivedMemberPointer ||
3240 CK == CK_ReinterpretMemberPointer);
3241 // If src is null, emit a new null for dst. We can't return src because dst
3242 // might have a new representation.
3243 if (MemberPointerConstantIsNull(SrcTy, Src))
3244 return EmitNullMemberPointer(DstTy);
3246 // We don't need to do anything for reinterpret_casts of non-null member
3247 // pointers. We should only get here when the two type representations have
3249 if (CK == CK_ReinterpretMemberPointer)
3252 CGBuilderTy Builder(CGM, CGM.getLLVMContext());
3253 auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion(
3254 SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder));
3259 CGCallee MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3260 CodeGenFunction &CGF, const Expr *E, Address This,
3261 llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr,
3262 const MemberPointerType *MPT) {
3263 assert(MPT->isMemberFunctionPointer());
3264 const FunctionProtoType *FPT =
3265 MPT->getPointeeType()->castAs<FunctionProtoType>();
3266 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3267 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(
3268 CGM.getTypes().arrangeCXXMethodType(RD, FPT, /*FD=*/nullptr));
3269 CGBuilderTy &Builder = CGF.Builder;
3271 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3273 // Extract the fields we need, regardless of model. We'll apply them if we
3275 llvm::Value *FunctionPointer = MemPtr;
3276 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3277 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3278 llvm::Value *VBPtrOffset = nullptr;
3279 if (MemPtr->getType()->isStructTy()) {
3280 // We need to extract values.
3282 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3283 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3284 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3285 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3286 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3287 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3288 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3291 if (VirtualBaseAdjustmentOffset) {
3292 ThisPtrForCall = AdjustVirtualBase(CGF, E, RD, This,
3293 VirtualBaseAdjustmentOffset, VBPtrOffset);
3295 ThisPtrForCall = This.getPointer();
3298 if (NonVirtualBaseAdjustment) {
3299 // Apply the adjustment and cast back to the original struct type.
3300 llvm::Value *Ptr = Builder.CreateBitCast(ThisPtrForCall, CGF.Int8PtrTy);
3301 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3302 ThisPtrForCall = Builder.CreateBitCast(Ptr, ThisPtrForCall->getType(),
3307 Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3308 CGCallee Callee(FPT, FunctionPointer);
3312 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3313 return new MicrosoftCXXABI(CGM);
3316 // MS RTTI Overview:
3317 // The run time type information emitted by cl.exe contains 5 distinct types of
3318 // structures. Many of them reference each other.
3320 // TypeInfo: Static classes that are returned by typeid.
3322 // CompleteObjectLocator: Referenced by vftables. They contain information
3323 // required for dynamic casting, including OffsetFromTop. They also contain
3324 // a reference to the TypeInfo for the type and a reference to the
3325 // CompleteHierarchyDescriptor for the type.
3327 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3328 // Used during dynamic_cast to walk a class hierarchy. References a base
3329 // class array and the size of said array.
3331 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3332 // somewhat of a misnomer because the most derived class is also in the list
3333 // as well as multiple copies of virtual bases (if they occur multiple times
3334 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3335 // every path in the hierarchy, in pre-order depth first order. Note, we do
3336 // not declare a specific llvm type for BaseClassArray, it's merely an array
3337 // of BaseClassDescriptor pointers.
3339 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3340 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3341 // BaseClassArray is. It contains information about a class within a
3342 // hierarchy such as: is this base is ambiguous and what is its offset in the
3343 // vbtable. The names of the BaseClassDescriptors have all of their fields
3344 // mangled into them so they can be aggressively deduplicated by the linker.
3346 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3347 StringRef MangledName("\01??_7type_info@@6B@");
3348 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3350 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3352 llvm::GlobalVariable::ExternalLinkage,
3353 /*Initializer=*/nullptr, MangledName);
3358 /// \brief A Helper struct that stores information about a class in a class
3359 /// hierarchy. The information stored in these structs struct is used during
3360 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3361 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3362 // implicit depth first pre-order tree connectivity. getFirstChild and
3363 // getNextSibling allow us to walk the tree efficiently.
3364 struct MSRTTIClass {
3366 IsPrivateOnPath = 1 | 8,
3370 HasHierarchyDescriptor = 64
3372 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3373 uint32_t initialize(const MSRTTIClass *Parent,
3374 const CXXBaseSpecifier *Specifier);
3376 MSRTTIClass *getFirstChild() { return this + 1; }
3377 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3378 return Child + 1 + Child->NumBases;
3381 const CXXRecordDecl *RD, *VirtualRoot;
3382 uint32_t Flags, NumBases, OffsetInVBase;
3385 /// \brief Recursively initialize the base class array.
3386 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3387 const CXXBaseSpecifier *Specifier) {
3388 Flags = HasHierarchyDescriptor;
3390 VirtualRoot = nullptr;
3393 if (Specifier->getAccessSpecifier() != AS_public)
3394 Flags |= IsPrivate | IsPrivateOnPath;
3395 if (Specifier->isVirtual()) {
3400 if (Parent->Flags & IsPrivateOnPath)
3401 Flags |= IsPrivateOnPath;
3402 VirtualRoot = Parent->VirtualRoot;
3403 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3404 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3408 MSRTTIClass *Child = getFirstChild();
3409 for (const CXXBaseSpecifier &Base : RD->bases()) {
3410 NumBases += Child->initialize(this, &Base) + 1;
3411 Child = getNextChild(Child);
3416 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3417 switch (Ty->getLinkage()) {
3419 case InternalLinkage:
3420 case UniqueExternalLinkage:
3421 return llvm::GlobalValue::InternalLinkage;
3423 case VisibleNoLinkage:
3424 case ExternalLinkage:
3425 return llvm::GlobalValue::LinkOnceODRLinkage;
3427 llvm_unreachable("Invalid linkage!");
3430 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3431 /// calls to the module and information about the most derived class in a
3433 struct MSRTTIBuilder {
3435 HasBranchingHierarchy = 1,
3436 HasVirtualBranchingHierarchy = 2,
3437 HasAmbiguousBases = 4
3440 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3441 : CGM(ABI.CGM), Context(CGM.getContext()),
3442 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3443 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3446 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3447 llvm::GlobalVariable *
3448 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3449 llvm::GlobalVariable *getClassHierarchyDescriptor();
3450 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo &Info);
3453 ASTContext &Context;
3454 llvm::LLVMContext &VMContext;
3455 llvm::Module &Module;
3456 const CXXRecordDecl *RD;
3457 llvm::GlobalVariable::LinkageTypes Linkage;
3458 MicrosoftCXXABI &ABI;
3463 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3465 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3466 const CXXRecordDecl *RD) {
3467 Classes.push_back(MSRTTIClass(RD));
3468 for (const CXXBaseSpecifier &Base : RD->bases())
3469 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3472 /// \brief Find ambiguity among base classes.
3474 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3475 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3476 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3477 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3478 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3479 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3480 !VirtualBases.insert(Class->RD).second) {
3481 Class = MSRTTIClass::getNextChild(Class);
3484 if (!UniqueBases.insert(Class->RD).second)
3485 AmbiguousBases.insert(Class->RD);
3488 if (AmbiguousBases.empty())
3490 for (MSRTTIClass &Class : Classes)
3491 if (AmbiguousBases.count(Class.RD))
3492 Class.Flags |= MSRTTIClass::IsAmbiguous;
3495 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3496 SmallString<256> MangledName;
3498 llvm::raw_svector_ostream Out(MangledName);
3499 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3502 // Check to see if we've already declared this ClassHierarchyDescriptor.
3503 if (auto CHD = Module.getNamedGlobal(MangledName))
3506 // Serialize the class hierarchy and initialize the CHD Fields.
3507 SmallVector<MSRTTIClass, 8> Classes;
3508 serializeClassHierarchy(Classes, RD);
3509 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3510 detectAmbiguousBases(Classes);
3512 for (auto Class : Classes) {
3513 if (Class.RD->getNumBases() > 1)
3514 Flags |= HasBranchingHierarchy;
3515 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3516 // believe the field isn't actually used.
3517 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3518 Flags |= HasAmbiguousBases;
3520 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3521 Flags |= HasVirtualBranchingHierarchy;
3522 // These gep indices are used to get the address of the first element of the
3523 // base class array.
3524 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3525 llvm::ConstantInt::get(CGM.IntTy, 0)};
3527 // Forward-declare the class hierarchy descriptor
3528 auto Type = ABI.getClassHierarchyDescriptorType();
3529 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3530 /*Initializer=*/nullptr,
3532 if (CHD->isWeakForLinker())
3533 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3535 auto *Bases = getBaseClassArray(Classes);
3537 // Initialize the base class ClassHierarchyDescriptor.
3538 llvm::Constant *Fields[] = {
3539 llvm::ConstantInt::get(CGM.IntTy, 0), // reserved by the runtime
3540 llvm::ConstantInt::get(CGM.IntTy, Flags),
3541 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3542 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3543 Bases->getValueType(), Bases,
3544 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3546 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3550 llvm::GlobalVariable *
3551 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3552 SmallString<256> MangledName;
3554 llvm::raw_svector_ostream Out(MangledName);
3555 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3558 // Forward-declare the base class array.
3559 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3560 // mode) bytes of padding. We provide a pointer sized amount of padding by
3561 // adding +1 to Classes.size(). The sections have pointer alignment and are
3562 // marked pick-any so it shouldn't matter.
3563 llvm::Type *PtrType = ABI.getImageRelativeType(
3564 ABI.getBaseClassDescriptorType()->getPointerTo());
3565 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3567 new llvm::GlobalVariable(Module, ArrType,
3568 /*Constant=*/true, Linkage,
3569 /*Initializer=*/nullptr, MangledName);
3570 if (BCA->isWeakForLinker())
3571 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3573 // Initialize the BaseClassArray.
3574 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3575 for (MSRTTIClass &Class : Classes)
3576 BaseClassArrayData.push_back(
3577 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3578 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3579 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3583 llvm::GlobalVariable *
3584 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3585 // Compute the fields for the BaseClassDescriptor. They are computed up front
3586 // because they are mangled into the name of the object.
3587 uint32_t OffsetInVBTable = 0;
3588 int32_t VBPtrOffset = -1;
3589 if (Class.VirtualRoot) {
3590 auto &VTableContext = CGM.getMicrosoftVTableContext();
3591 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3592 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3595 SmallString<256> MangledName;
3597 llvm::raw_svector_ostream Out(MangledName);
3598 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3599 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3603 // Check to see if we've already declared this object.
3604 if (auto BCD = Module.getNamedGlobal(MangledName))
3607 // Forward-declare the base class descriptor.
3608 auto Type = ABI.getBaseClassDescriptorType();
3610 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3611 /*Initializer=*/nullptr, MangledName);
3612 if (BCD->isWeakForLinker())
3613 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3615 // Initialize the BaseClassDescriptor.
3616 llvm::Constant *Fields[] = {
3617 ABI.getImageRelativeConstant(
3618 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3619 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3620 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3621 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3622 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3623 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3624 ABI.getImageRelativeConstant(
3625 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3627 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3631 llvm::GlobalVariable *
3632 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo &Info) {
3633 SmallString<256> MangledName;
3635 llvm::raw_svector_ostream Out(MangledName);
3636 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info.MangledPath, Out);
3639 // Check to see if we've already computed this complete object locator.
3640 if (auto COL = Module.getNamedGlobal(MangledName))
3643 // Compute the fields of the complete object locator.
3644 int OffsetToTop = Info.FullOffsetInMDC.getQuantity();
3645 int VFPtrOffset = 0;
3646 // The offset includes the vtordisp if one exists.
3647 if (const CXXRecordDecl *VBase = Info.getVBaseWithVPtr())
3648 if (Context.getASTRecordLayout(RD)
3649 .getVBaseOffsetsMap()
3651 ->second.hasVtorDisp())
3652 VFPtrOffset = Info.NonVirtualOffset.getQuantity() + 4;
3654 // Forward-declare the complete object locator.
3655 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3656 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3657 /*Initializer=*/nullptr, MangledName);
3659 // Initialize the CompleteObjectLocator.
3660 llvm::Constant *Fields[] = {
3661 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3662 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3663 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3664 ABI.getImageRelativeConstant(
3665 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3666 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3667 ABI.getImageRelativeConstant(COL),
3669 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3670 if (!ABI.isImageRelative())
3671 FieldsRef = FieldsRef.drop_back();
3672 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3673 if (COL->isWeakForLinker())
3674 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3678 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3679 bool &IsConst, bool &IsVolatile,
3680 bool &IsUnaligned) {
3681 T = Context.getExceptionObjectType(T);
3683 // C++14 [except.handle]p3:
3684 // A handler is a match for an exception object of type E if [...]
3685 // - the handler is of type cv T or const T& where T is a pointer type and
3686 // E is a pointer type that can be converted to T by [...]
3687 // - a qualification conversion
3690 IsUnaligned = false;
3691 QualType PointeeType = T->getPointeeType();
3692 if (!PointeeType.isNull()) {
3693 IsConst = PointeeType.isConstQualified();
3694 IsVolatile = PointeeType.isVolatileQualified();
3695 IsUnaligned = PointeeType.getQualifiers().hasUnaligned();
3698 // Member pointer types like "const int A::*" are represented by having RTTI
3699 // for "int A::*" and separately storing the const qualifier.
3700 if (const auto *MPTy = T->getAs<MemberPointerType>())
3701 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3704 // Pointer types like "const int * const *" are represented by having RTTI
3705 // for "const int **" and separately storing the const qualifier.
3706 if (T->isPointerType())
3707 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3713 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3714 QualType CatchHandlerType) {
3715 // TypeDescriptors for exceptions never have qualified pointer types,
3716 // qualifiers are stored seperately in order to support qualification
3718 bool IsConst, IsVolatile, IsUnaligned;
3720 decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile, IsUnaligned);
3722 bool IsReference = CatchHandlerType->isReferenceType();
3734 return CatchTypeInfo{getAddrOfRTTIDescriptor(Type)->stripPointerCasts(),
3738 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3739 /// llvm::GlobalVariable * because different type descriptors have different
3740 /// types, and need to be abstracted. They are abstracting by casting the
3741 /// address to an Int8PtrTy.
3742 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3743 SmallString<256> MangledName;
3745 llvm::raw_svector_ostream Out(MangledName);
3746 getMangleContext().mangleCXXRTTI(Type, Out);
3749 // Check to see if we've already declared this TypeDescriptor.
3750 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3751 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3753 // Compute the fields for the TypeDescriptor.
3754 SmallString<256> TypeInfoString;
3756 llvm::raw_svector_ostream Out(TypeInfoString);
3757 getMangleContext().mangleCXXRTTIName(Type, Out);
3760 // Declare and initialize the TypeDescriptor.
3761 llvm::Constant *Fields[] = {
3762 getTypeInfoVTable(CGM), // VFPtr
3763 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3764 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3765 llvm::StructType *TypeDescriptorType =
3766 getTypeDescriptorType(TypeInfoString);
3767 auto *Var = new llvm::GlobalVariable(
3768 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3769 getLinkageForRTTI(Type),
3770 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3772 if (Var->isWeakForLinker())
3773 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3774 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3777 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3778 llvm::GlobalVariable *
3779 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3780 const VPtrInfo &Info) {
3781 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3784 static void emitCXXConstructor(CodeGenModule &CGM,
3785 const CXXConstructorDecl *ctor,
3786 StructorType ctorType) {
3787 // There are no constructor variants, always emit the complete destructor.
3788 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3789 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3792 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3793 StructorType dtorType) {
3794 // The complete destructor is equivalent to the base destructor for
3795 // classes with no virtual bases, so try to emit it as an alias.
3796 if (!dtor->getParent()->getNumVBases() &&
3797 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3798 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3799 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3800 if (ProducedAlias) {
3801 if (dtorType == StructorType::Complete)
3803 if (dtor->isVirtual())
3804 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3808 // The base destructor is equivalent to the base destructor of its
3809 // base class if there is exactly one non-virtual base class with a
3810 // non-trivial destructor, there are no fields with a non-trivial
3811 // destructor, and the body of the destructor is trivial.
3812 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3815 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3816 if (Fn->isWeakForLinker())
3817 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3820 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3821 StructorType Type) {
3822 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3823 emitCXXConstructor(CGM, CD, Type);
3826 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3830 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3832 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3834 // Calculate the mangled name.
3835 SmallString<256> ThunkName;
3836 llvm::raw_svector_ostream Out(ThunkName);
3837 getMangleContext().mangleCXXCtor(CD, CT, Out);
3839 // If the thunk has been generated previously, just return it.
3840 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3841 return cast<llvm::Function>(GV);
3843 // Create the llvm::Function.
3844 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3845 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3846 const CXXRecordDecl *RD = CD->getParent();
3847 QualType RecordTy = getContext().getRecordType(RD);
3848 llvm::Function *ThunkFn = llvm::Function::Create(
3849 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3850 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3851 FnInfo.getEffectiveCallingConvention()));
3852 if (ThunkFn->isWeakForLinker())
3853 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
3854 bool IsCopy = CT == Ctor_CopyingClosure;
3857 CodeGenFunction CGF(CGM);
3858 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3860 // Build FunctionArgs.
3861 FunctionArgList FunctionArgs;
3863 // A constructor always starts with a 'this' pointer as its first argument.
3864 buildThisParam(CGF, FunctionArgs);
3866 // Following the 'this' pointer is a reference to the source object that we
3867 // are copying from.
3868 ImplicitParamDecl SrcParam(
3869 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3870 getContext().getLValueReferenceType(RecordTy,
3871 /*SpelledAsLValue=*/true));
3873 FunctionArgs.push_back(&SrcParam);
3875 // Constructors for classes which utilize virtual bases have an additional
3876 // parameter which indicates whether or not it is being delegated to by a more
3877 // derived constructor.
3878 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3879 &getContext().Idents.get("is_most_derived"),
3880 getContext().IntTy);
3881 // Only add the parameter to the list if thie class has virtual bases.
3882 if (RD->getNumVBases() > 0)
3883 FunctionArgs.push_back(&IsMostDerived);
3885 // Start defining the function.
3886 auto NL = ApplyDebugLocation::CreateEmpty(CGF);
3887 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3888 FunctionArgs, CD->getLocation(), SourceLocation());
3889 // Create a scope with an artificial location for the body of this function.
3890 auto AL = ApplyDebugLocation::CreateArtificial(CGF);
3892 llvm::Value *This = getThisValue(CGF);
3894 llvm::Value *SrcVal =
3895 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3900 // Push the this ptr.
3901 Args.add(RValue::get(This), CD->getThisType(getContext()));
3903 // Push the src ptr.
3905 Args.add(RValue::get(SrcVal), SrcParam.getType());
3907 // Add the rest of the default arguments.
3908 SmallVector<const Stmt *, 4> ArgVec;
3909 ArrayRef<ParmVarDecl *> params = CD->parameters().drop_front(IsCopy ? 1 : 0);
3910 for (const ParmVarDecl *PD : params) {
3911 assert(PD->hasDefaultArg() && "ctor closure lacks default args");
3912 ArgVec.push_back(PD->getDefaultArg());
3915 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3917 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3918 CGF.EmitCallArgs(Args, FPT, llvm::makeArrayRef(ArgVec), CD, IsCopy ? 1 : 0);
3920 // Insert any ABI-specific implicit constructor arguments.
3921 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3922 /*ForVirtualBase=*/false,
3923 /*Delegating=*/false, Args);
3925 // Call the destructor with our arguments.
3926 llvm::Constant *CalleePtr =
3927 CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3928 CGCallee Callee = CGCallee::forDirect(CalleePtr, CD);
3929 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3930 Args, CD, Ctor_Complete, ExtraArgs);
3931 CGF.EmitCall(CalleeInfo, Callee, ReturnValueSlot(), Args);
3933 Cleanups.ForceCleanup();
3935 // Emit the ret instruction, remove any temporary instructions created for the
3937 CGF.FinishFunction(SourceLocation());
3942 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3944 int32_t VBPtrOffset,
3946 assert(!T->isReferenceType());
3948 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3949 const CXXConstructorDecl *CD =
3950 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3951 CXXCtorType CT = Ctor_Complete;
3953 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3954 CT = Ctor_CopyingClosure;
3956 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3957 SmallString<256> MangledName;
3959 llvm::raw_svector_ostream Out(MangledName);
3960 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3961 VBPtrOffset, VBIndex, Out);
3963 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3964 return getImageRelativeConstant(GV);
3966 // The TypeDescriptor is used by the runtime to determine if a catch handler
3967 // is appropriate for the exception object.
3968 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3970 // The runtime is responsible for calling the copy constructor if the
3971 // exception is caught by value.
3972 llvm::Constant *CopyCtor;
3974 if (CT == Ctor_CopyingClosure)
3975 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3977 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3979 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3981 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3983 CopyCtor = getImageRelativeConstant(CopyCtor);
3985 bool IsScalar = !RD;
3986 bool HasVirtualBases = false;
3987 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3988 QualType PointeeType = T;
3989 if (T->isPointerType())
3990 PointeeType = T->getPointeeType();
3991 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3992 HasVirtualBases = RD->getNumVBases() > 0;
3993 if (IdentifierInfo *II = RD->getIdentifier())
3994 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3997 // Encode the relevant CatchableType properties into the Flags bitfield.
3998 // FIXME: Figure out how bits 2 or 8 can get set.
4002 if (HasVirtualBases)
4007 llvm::Constant *Fields[] = {
4008 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4009 TD, // TypeDescriptor
4010 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
4011 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
4012 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
4013 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
4014 CopyCtor // CopyCtor
4016 llvm::StructType *CTType = getCatchableTypeType();
4017 auto *GV = new llvm::GlobalVariable(
4018 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
4019 llvm::ConstantStruct::get(CTType, Fields), MangledName);
4020 GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
4021 GV->setSection(".xdata");
4022 if (GV->isWeakForLinker())
4023 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4024 return getImageRelativeConstant(GV);
4027 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
4028 assert(!T->isReferenceType());
4030 // See if we've already generated a CatchableTypeArray for this type before.
4031 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
4035 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
4036 // using a SmallSetVector. Duplicates may arise due to virtual bases
4037 // occurring more than once in the hierarchy.
4038 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
4040 // C++14 [except.handle]p3:
4041 // A handler is a match for an exception object of type E if [...]
4042 // - the handler is of type cv T or cv T& and T is an unambiguous public
4043 // base class of E, or
4044 // - the handler is of type cv T or const T& where T is a pointer type and
4045 // E is a pointer type that can be converted to T by [...]
4046 // - a standard pointer conversion (4.10) not involving conversions to
4047 // pointers to private or protected or ambiguous classes
4048 const CXXRecordDecl *MostDerivedClass = nullptr;
4049 bool IsPointer = T->isPointerType();
4051 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
4053 MostDerivedClass = T->getAsCXXRecordDecl();
4055 // Collect all the unambiguous public bases of the MostDerivedClass.
4056 if (MostDerivedClass) {
4057 const ASTContext &Context = getContext();
4058 const ASTRecordLayout &MostDerivedLayout =
4059 Context.getASTRecordLayout(MostDerivedClass);
4060 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
4061 SmallVector<MSRTTIClass, 8> Classes;
4062 serializeClassHierarchy(Classes, MostDerivedClass);
4063 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
4064 detectAmbiguousBases(Classes);
4065 for (const MSRTTIClass &Class : Classes) {
4066 // Skip any ambiguous or private bases.
4068 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
4070 // Write down how to convert from a derived pointer to a base pointer.
4071 uint32_t OffsetInVBTable = 0;
4072 int32_t VBPtrOffset = -1;
4073 if (Class.VirtualRoot) {
4075 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
4076 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
4079 // Turn our record back into a pointer if the exception object is a
4081 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
4083 RTTITy = Context.getPointerType(RTTITy);
4084 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
4085 VBPtrOffset, OffsetInVBTable));
4089 // C++14 [except.handle]p3:
4090 // A handler is a match for an exception object of type E if
4091 // - The handler is of type cv T or cv T& and E and T are the same type
4092 // (ignoring the top-level cv-qualifiers)
4093 CatchableTypes.insert(getCatchableType(T));
4095 // C++14 [except.handle]p3:
4096 // A handler is a match for an exception object of type E if
4097 // - the handler is of type cv T or const T& where T is a pointer type and
4098 // E is a pointer type that can be converted to T by [...]
4099 // - a standard pointer conversion (4.10) not involving conversions to
4100 // pointers to private or protected or ambiguous classes
4102 // C++14 [conv.ptr]p2:
4103 // A prvalue of type "pointer to cv T," where T is an object type, can be
4104 // converted to a prvalue of type "pointer to cv void".
4105 if (IsPointer && T->getPointeeType()->isObjectType())
4106 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4108 // C++14 [except.handle]p3:
4109 // A handler is a match for an exception object of type E if [...]
4110 // - the handler is of type cv T or const T& where T is a pointer or
4111 // pointer to member type and E is std::nullptr_t.
4113 // We cannot possibly list all possible pointer types here, making this
4114 // implementation incompatible with the standard. However, MSVC includes an
4115 // entry for pointer-to-void in this case. Let's do the same.
4116 if (T->isNullPtrType())
4117 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
4119 uint32_t NumEntries = CatchableTypes.size();
4120 llvm::Type *CTType =
4121 getImageRelativeType(getCatchableTypeType()->getPointerTo());
4122 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
4123 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
4124 llvm::Constant *Fields[] = {
4125 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
4126 llvm::ConstantArray::get(
4127 AT, llvm::makeArrayRef(CatchableTypes.begin(),
4128 CatchableTypes.end())) // CatchableTypes
4130 SmallString<256> MangledName;
4132 llvm::raw_svector_ostream Out(MangledName);
4133 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
4135 CTA = new llvm::GlobalVariable(
4136 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
4137 llvm::ConstantStruct::get(CTAType, Fields), MangledName);
4138 CTA->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
4139 CTA->setSection(".xdata");
4140 if (CTA->isWeakForLinker())
4141 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
4145 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
4146 bool IsConst, IsVolatile, IsUnaligned;
4147 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile, IsUnaligned);
4149 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
4150 // the exception object may be caught as.
4151 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
4152 // The first field in a CatchableTypeArray is the number of CatchableTypes.
4153 // This is used as a component of the mangled name which means that we need to
4154 // know what it is in order to see if we have previously generated the
4156 uint32_t NumEntries =
4157 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
4158 ->getLimitedValue();
4160 SmallString<256> MangledName;
4162 llvm::raw_svector_ostream Out(MangledName);
4163 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, IsUnaligned,
4167 // Reuse a previously generated ThrowInfo if we have generated an appropriate
4169 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
4172 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
4173 // be at least as CV qualified. Encode this requirement into the Flags
4183 // The cleanup-function (a destructor) must be called when the exception
4184 // object's lifetime ends.
4185 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
4186 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4187 if (CXXDestructorDecl *DtorD = RD->getDestructor())
4188 if (!DtorD->isTrivial())
4189 CleanupFn = llvm::ConstantExpr::getBitCast(
4190 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
4192 // This is unused as far as we can tell, initialize it to null.
4193 llvm::Constant *ForwardCompat =
4194 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
4195 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
4196 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
4197 llvm::StructType *TIType = getThrowInfoType();
4198 llvm::Constant *Fields[] = {
4199 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
4200 getImageRelativeConstant(CleanupFn), // CleanupFn
4201 ForwardCompat, // ForwardCompat
4202 PointerToCatchableTypes // CatchableTypeArray
4204 auto *GV = new llvm::GlobalVariable(
4205 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
4206 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
4207 GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
4208 GV->setSection(".xdata");
4209 if (GV->isWeakForLinker())
4210 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
4214 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
4215 const Expr *SubExpr = E->getSubExpr();
4216 QualType ThrowType = SubExpr->getType();
4217 // The exception object lives on the stack and it's address is passed to the
4218 // runtime function.
4219 Address AI = CGF.CreateMemTemp(ThrowType);
4220 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4223 // The so-called ThrowInfo is used to describe how the exception object may be
4225 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4227 // Call into the runtime to throw the exception.
4228 llvm::Value *Args[] = {
4229 CGF.Builder.CreateBitCast(AI.getPointer(), CGM.Int8PtrTy),
4232 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);