1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
88 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
89 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
90 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
92 llvm::Type *StdTypeInfoPtrTy) override;
94 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
95 QualType SrcRecordTy) override;
97 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
98 QualType SrcRecordTy, QualType DestTy,
99 QualType DestRecordTy,
100 llvm::BasicBlock *CastEnd) override;
102 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
103 QualType SrcRecordTy,
104 QualType DestTy) override;
106 bool EmitBadCastCall(CodeGenFunction &CGF) override;
109 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
110 const CXXRecordDecl *ClassDecl,
111 const CXXRecordDecl *BaseClassDecl) override;
114 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
115 const CXXRecordDecl *RD) override;
117 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
118 const CXXRecordDecl *RD) override;
120 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
122 // Background on MSVC destructors
123 // ==============================
125 // Both Itanium and MSVC ABIs have destructor variants. The variant names
126 // roughly correspond in the following way:
128 // Base -> no name, just ~Class
129 // Complete -> vbase destructor
130 // Deleting -> scalar deleting destructor
131 // vector deleting destructor
133 // The base and complete destructors are the same as in Itanium, although the
134 // complete destructor does not accept a VTT parameter when there are virtual
135 // bases. A separate mechanism involving vtordisps is used to ensure that
136 // virtual methods of destroyed subobjects are not called.
138 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
139 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
140 // pointer points to an array. The scalar deleting destructor assumes that
141 // bit 2 is zero, and therefore does not contain a loop.
143 // For virtual destructors, only one entry is reserved in the vftable, and it
144 // always points to the vector deleting destructor. The vector deleting
145 // destructor is the most general, so it can be used to destroy objects in
146 // place, delete single heap objects, or delete arrays.
148 // A TU defining a non-inline destructor is only guaranteed to emit a base
149 // destructor, and all of the other variants are emitted on an as-needed basis
150 // in COMDATs. Because a non-base destructor can be emitted in a TU that
151 // lacks a definition for the destructor, non-base destructors must always
152 // delegate to or alias the base destructor.
154 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
155 SmallVectorImpl<CanQualType> &ArgTys) override;
157 /// Non-base dtors should be emitted as delegating thunks in this ABI.
158 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
159 CXXDtorType DT) const override {
160 return DT != Dtor_Base;
163 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
165 const CXXRecordDecl *
166 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
167 MD = MD->getCanonicalDecl();
168 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
169 MicrosoftVTableContext::MethodVFTableLocation ML =
170 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
171 // The vbases might be ordered differently in the final overrider object
172 // and the complete object, so the "this" argument may sometimes point to
173 // memory that has no particular type (e.g. past the complete object).
174 // In this case, we just use a generic pointer type.
175 // FIXME: might want to have a more precise type in the non-virtual
176 // multiple inheritance case.
177 if (ML.VBase || !ML.VFPtrOffset.isZero())
180 return MD->getParent();
184 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
186 bool VirtualCall) override;
188 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
189 FunctionArgList &Params) override;
191 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
192 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
194 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
196 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
197 const CXXConstructorDecl *D,
198 CXXCtorType Type, bool ForVirtualBase,
200 CallArgList &Args) override;
202 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
203 CXXDtorType Type, bool ForVirtualBase,
204 bool Delegating, llvm::Value *This) override;
206 void emitVTableDefinitions(CodeGenVTables &CGVT,
207 const CXXRecordDecl *RD) override;
209 llvm::Value *getVTableAddressPointInStructor(
210 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
211 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
212 bool &NeedsVirtualOffset) override;
215 getVTableAddressPointForConstExpr(BaseSubobject Base,
216 const CXXRecordDecl *VTableClass) override;
218 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
219 CharUnits VPtrOffset) override;
221 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
223 llvm::Type *Ty) override;
225 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
226 const CXXDestructorDecl *Dtor,
227 CXXDtorType DtorType,
229 const CXXMemberCallExpr *CE) override;
231 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
232 CallArgList &CallArgs) override {
233 assert(GD.getDtorType() == Dtor_Deleting &&
234 "Only deleting destructor thunks are available in this ABI");
235 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
236 CGM.getContext().IntTy);
239 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
241 llvm::GlobalVariable *
242 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
243 llvm::GlobalVariable::LinkageTypes Linkage);
245 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
246 llvm::GlobalVariable *GV) const;
248 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
249 GlobalDecl GD, bool ReturnAdjustment) override {
250 // Never dllimport/dllexport thunks.
251 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
254 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
256 if (Linkage == GVA_Internal)
257 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
258 else if (ReturnAdjustment)
259 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
261 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
264 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
265 const ThisAdjustment &TA) override;
267 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
268 const ReturnAdjustment &RA) override;
270 void EmitThreadLocalInitFuncs(
272 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
274 ArrayRef<llvm::Function *> CXXThreadLocalInits,
275 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
277 bool usesThreadWrapperFunction() const override { return false; }
278 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
279 QualType LValType) override;
281 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
282 llvm::GlobalVariable *DeclPtr,
283 bool PerformInit) override;
284 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
285 llvm::Constant *Dtor, llvm::Constant *Addr) override;
287 // ==== Notes on array cookies =========
289 // MSVC seems to only use cookies when the class has a destructor; a
290 // two-argument usual array deallocation function isn't sufficient.
292 // For example, this code prints "100" and "1":
295 // void *operator new[](size_t sz) {
296 // printf("%u\n", sz);
297 // return malloc(sz);
299 // void operator delete[](void *p, size_t sz) {
300 // printf("%u\n", sz);
305 // A *p = new A[100];
308 // Whereas it prints "104" and "104" if you give A a destructor.
310 bool requiresArrayCookie(const CXXDeleteExpr *expr,
311 QualType elementType) override;
312 bool requiresArrayCookie(const CXXNewExpr *expr) override;
313 CharUnits getArrayCookieSizeImpl(QualType type) override;
314 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
316 llvm::Value *NumElements,
317 const CXXNewExpr *expr,
318 QualType ElementType) override;
319 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
320 llvm::Value *allocPtr,
321 CharUnits cookieSize) override;
323 friend struct MSRTTIBuilder;
325 bool isImageRelative() const {
326 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
329 // 5 routines for constructing the llvm types for MS RTTI structs.
330 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
331 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
332 TDTypeName += llvm::utostr(TypeInfoString.size());
333 llvm::StructType *&TypeDescriptorType =
334 TypeDescriptorTypeMap[TypeInfoString.size()];
335 if (TypeDescriptorType)
336 return TypeDescriptorType;
337 llvm::Type *FieldTypes[] = {
340 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
342 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
343 return TypeDescriptorType;
346 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
347 if (!isImageRelative())
352 llvm::StructType *getBaseClassDescriptorType() {
353 if (BaseClassDescriptorType)
354 return BaseClassDescriptorType;
355 llvm::Type *FieldTypes[] = {
356 getImageRelativeType(CGM.Int8PtrTy),
362 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
364 BaseClassDescriptorType = llvm::StructType::create(
365 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
366 return BaseClassDescriptorType;
369 llvm::StructType *getClassHierarchyDescriptorType() {
370 if (ClassHierarchyDescriptorType)
371 return ClassHierarchyDescriptorType;
372 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
373 ClassHierarchyDescriptorType = llvm::StructType::create(
374 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
375 llvm::Type *FieldTypes[] = {
379 getImageRelativeType(
380 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
382 ClassHierarchyDescriptorType->setBody(FieldTypes);
383 return ClassHierarchyDescriptorType;
386 llvm::StructType *getCompleteObjectLocatorType() {
387 if (CompleteObjectLocatorType)
388 return CompleteObjectLocatorType;
389 CompleteObjectLocatorType = llvm::StructType::create(
390 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
391 llvm::Type *FieldTypes[] = {
395 getImageRelativeType(CGM.Int8PtrTy),
396 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
397 getImageRelativeType(CompleteObjectLocatorType),
399 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
400 if (!isImageRelative())
401 FieldTypesRef = FieldTypesRef.drop_back();
402 CompleteObjectLocatorType->setBody(FieldTypesRef);
403 return CompleteObjectLocatorType;
406 llvm::GlobalVariable *getImageBase() {
407 StringRef Name = "__ImageBase";
408 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
411 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
413 llvm::GlobalValue::ExternalLinkage,
414 /*Initializer=*/nullptr, Name);
417 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
418 if (!isImageRelative())
421 if (PtrVal->isNullValue())
422 return llvm::Constant::getNullValue(CGM.IntTy);
424 llvm::Constant *ImageBaseAsInt =
425 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
426 llvm::Constant *PtrValAsInt =
427 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
428 llvm::Constant *Diff =
429 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
430 /*HasNUW=*/true, /*HasNSW=*/true);
431 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
435 MicrosoftMangleContext &getMangleContext() {
436 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
439 llvm::Constant *getZeroInt() {
440 return llvm::ConstantInt::get(CGM.IntTy, 0);
443 llvm::Constant *getAllOnesInt() {
444 return llvm::Constant::getAllOnesValue(CGM.IntTy);
447 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
448 return C ? C : getZeroInt();
451 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
452 return C ? C : getZeroInt();
455 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
458 GetNullMemberPointerFields(const MemberPointerType *MPT,
459 llvm::SmallVectorImpl<llvm::Constant *> &fields);
461 /// \brief Shared code for virtual base adjustment. Returns the offset from
462 /// the vbptr to the virtual base. Optionally returns the address of the
464 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
466 llvm::Value *VBPtrOffset,
467 llvm::Value *VBTableOffset,
468 llvm::Value **VBPtr = nullptr);
470 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
473 int32_t VBTableOffset,
474 llvm::Value **VBPtr = nullptr) {
475 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
476 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
477 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
478 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
481 std::pair<llvm::Value *, llvm::Value *>
482 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
483 QualType SrcRecordTy);
485 /// \brief Performs a full virtual base adjustment. Used to dereference
486 /// pointers to members of virtual bases.
487 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
488 const CXXRecordDecl *RD, llvm::Value *Base,
489 llvm::Value *VirtualBaseAdjustmentOffset,
490 llvm::Value *VBPtrOffset /* optional */);
492 /// \brief Emits a full member pointer with the fields common to data and
493 /// function member pointers.
494 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
495 bool IsMemberFunction,
496 const CXXRecordDecl *RD,
497 CharUnits NonVirtualBaseAdjustment);
499 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
500 const CXXMethodDecl *MD,
501 CharUnits NonVirtualBaseAdjustment);
503 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
506 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
507 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
509 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
510 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
512 /// \brief Generate a thunk for calling a virtual member function MD.
513 llvm::Function *EmitVirtualMemPtrThunk(
514 const CXXMethodDecl *MD,
515 const MicrosoftVTableContext::MethodVFTableLocation &ML);
518 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
520 bool isZeroInitializable(const MemberPointerType *MPT) override;
522 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
523 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
524 return RD->hasAttr<MSInheritanceAttr>();
527 bool isTypeInfoCalculable(QualType Ty) const override {
528 if (!CGCXXABI::isTypeInfoCalculable(Ty))
530 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
531 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
532 if (!RD->hasAttr<MSInheritanceAttr>())
538 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
540 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
541 CharUnits offset) override;
542 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
543 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
545 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
548 const MemberPointerType *MPT,
549 bool Inequality) override;
551 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
553 const MemberPointerType *MPT) override;
556 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
557 llvm::Value *Base, llvm::Value *MemPtr,
558 const MemberPointerType *MPT) override;
560 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
562 llvm::Value *Src) override;
564 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
565 llvm::Constant *Src) override;
568 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
569 llvm::Value *&This, llvm::Value *MemPtr,
570 const MemberPointerType *MPT) override;
572 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
574 llvm::StructType *getCatchableTypeType() {
575 if (CatchableTypeType)
576 return CatchableTypeType;
577 llvm::Type *FieldTypes[] = {
579 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
580 CGM.IntTy, // NonVirtualAdjustment
581 CGM.IntTy, // OffsetToVBPtr
582 CGM.IntTy, // VBTableIndex
584 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
586 CatchableTypeType = llvm::StructType::create(
587 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
588 return CatchableTypeType;
591 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
592 llvm::StructType *&CatchableTypeArrayType =
593 CatchableTypeArrayTypeMap[NumEntries];
594 if (CatchableTypeArrayType)
595 return CatchableTypeArrayType;
597 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
598 CTATypeName += llvm::utostr(NumEntries);
600 getImageRelativeType(getCatchableTypeType()->getPointerTo());
601 llvm::Type *FieldTypes[] = {
602 CGM.IntTy, // NumEntries
603 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
605 CatchableTypeArrayType =
606 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
607 return CatchableTypeArrayType;
610 llvm::StructType *getThrowInfoType() {
612 return ThrowInfoType;
613 llvm::Type *FieldTypes[] = {
615 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
616 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
617 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
619 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
621 return ThrowInfoType;
624 llvm::Constant *getThrowFn() {
625 // _CxxThrowException is passed an exception object and a ThrowInfo object
626 // which describes the exception.
627 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
628 llvm::FunctionType *FTy =
629 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
630 auto *Fn = cast<llvm::Function>(
631 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
632 // _CxxThrowException is stdcall on 32-bit x86 platforms.
633 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
634 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
638 llvm::Function *getAddrOfCXXCopyCtorClosure(const CXXConstructorDecl *CD);
640 llvm::Constant *getCatchableType(QualType T,
641 uint32_t NVOffset = 0,
642 int32_t VBPtrOffset = -1,
643 uint32_t VBIndex = 0);
645 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
647 llvm::GlobalVariable *getThrowInfo(QualType T);
650 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
651 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
652 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
653 /// \brief All the vftables that have been referenced.
654 VFTablesMapTy VFTablesMap;
655 VTablesMapTy VTablesMap;
657 /// \brief This set holds the record decls we've deferred vtable emission for.
658 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
661 /// \brief All the vbtables which have been referenced.
662 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
664 /// Info on the global variable used to guard initialization of static locals.
665 /// The BitIndex field is only used for externally invisible declarations.
667 GuardInfo() : Guard(nullptr), BitIndex(0) {}
668 llvm::GlobalVariable *Guard;
672 /// Map from DeclContext to the current guard variable. We assume that the
673 /// AST is visited in source code order.
674 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
676 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
677 llvm::StructType *BaseClassDescriptorType;
678 llvm::StructType *ClassHierarchyDescriptorType;
679 llvm::StructType *CompleteObjectLocatorType;
681 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
683 llvm::StructType *CatchableTypeType;
684 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
685 llvm::StructType *ThrowInfoType;
690 CGCXXABI::RecordArgABI
691 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
692 switch (CGM.getTarget().getTriple().getArch()) {
694 // FIXME: Implement for other architectures.
697 case llvm::Triple::x86:
698 // All record arguments are passed in memory on x86. Decide whether to
699 // construct the object directly in argument memory, or to construct the
700 // argument elsewhere and copy the bytes during the call.
702 // If C++ prohibits us from making a copy, construct the arguments directly
703 // into argument memory.
704 if (!canCopyArgument(RD))
705 return RAA_DirectInMemory;
707 // Otherwise, construct the argument into a temporary and copy the bytes
708 // into the outgoing argument memory.
711 case llvm::Triple::x86_64:
712 // Win64 passes objects with non-trivial copy ctors indirectly.
713 if (RD->hasNonTrivialCopyConstructor())
716 // If an object has a destructor, we'd really like to pass it indirectly
717 // because it allows us to elide copies. Unfortunately, MSVC makes that
718 // impossible for small types, which it will pass in a single register or
719 // stack slot. Most objects with dtors are large-ish, so handle that early.
720 // We can't call out all large objects as being indirect because there are
721 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
722 // how we pass large POD types.
723 if (RD->hasNonTrivialDestructor() &&
724 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
727 // We have a trivial copy constructor or no copy constructors, but we have
728 // to make sure it isn't deleted.
729 bool CopyDeleted = false;
730 for (const CXXConstructorDecl *CD : RD->ctors()) {
731 if (CD->isCopyConstructor()) {
732 assert(CD->isTrivial());
733 // We had at least one undeleted trivial copy ctor. Return directly.
734 if (!CD->isDeleted())
740 // The trivial copy constructor was deleted. Return indirectly.
744 // There were no copy ctors. Return in RAX.
748 llvm_unreachable("invalid enum");
751 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
752 const CXXDeleteExpr *DE,
754 QualType ElementType,
755 const CXXDestructorDecl *Dtor) {
756 // FIXME: Provide a source location here even though there's no
757 // CXXMemberCallExpr for dtor call.
758 bool UseGlobalDelete = DE->isGlobalDelete();
759 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
760 llvm::Value *MDThis =
761 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
763 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
766 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
767 llvm::Value *Args[] = {
768 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
769 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
770 auto *Fn = getThrowFn();
772 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
774 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
778 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
779 CallEndCatchMSVC() {}
780 void Emit(CodeGenFunction &CGF, Flags flags) override {
781 CGF.EmitNounwindRuntimeCall(
782 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
787 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
788 const CXXCatchStmt *S) {
789 // In the MS ABI, the runtime handles the copy, and the catch handler is
790 // responsible for destruction.
791 VarDecl *CatchParam = S->getExceptionDecl();
792 llvm::Value *Exn = CGF.getExceptionFromSlot();
793 llvm::Function *BeginCatch =
794 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
797 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
798 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
799 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
803 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
804 llvm::Value *ParamAddr =
805 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
806 llvm::Value *Args[2] = {Exn, ParamAddr};
807 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
808 // FIXME: Do we really need exceptional endcatch cleanups?
809 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
810 CGF.EmitAutoVarCleanups(var);
813 std::pair<llvm::Value *, llvm::Value *>
814 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
815 QualType SrcRecordTy) {
816 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
817 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
818 const ASTContext &Context = CGF.getContext();
820 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
821 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
823 // Perform a base adjustment.
824 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
825 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
826 [&](const CXXBaseSpecifier &Base) {
827 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
828 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
830 llvm::Value *Offset = GetVirtualBaseClassOffset(
831 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
832 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
833 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
834 return std::make_pair(Value, Offset);
837 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
838 QualType SrcRecordTy) {
839 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
841 !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
844 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
845 llvm::Value *Argument) {
846 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
847 llvm::FunctionType *FTy =
848 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
849 llvm::Value *Args[] = {Argument};
850 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
851 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
854 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
855 llvm::CallSite Call =
856 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
857 Call.setDoesNotReturn();
858 CGF.Builder.CreateUnreachable();
861 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
862 QualType SrcRecordTy,
863 llvm::Value *ThisPtr,
864 llvm::Type *StdTypeInfoPtrTy) {
866 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
867 return CGF.Builder.CreateBitCast(
868 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
871 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
872 QualType SrcRecordTy) {
873 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
875 !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
878 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
879 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
880 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
881 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
883 llvm::Value *SrcRTTI =
884 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
885 llvm::Value *DestRTTI =
886 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
889 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
891 // PVOID __RTDynamicCast(
897 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
898 CGF.Int8PtrTy, CGF.Int32Ty};
899 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
900 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
902 llvm::Value *Args[] = {
903 Value, Offset, SrcRTTI, DestRTTI,
904 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
905 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
906 return CGF.Builder.CreateBitCast(Value, DestLTy);
910 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
911 QualType SrcRecordTy,
914 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
916 // PVOID __RTCastToVoid(
918 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
919 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
920 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
922 llvm::Value *Args[] = {Value};
923 return CGF.EmitRuntimeCall(Function, Args);
926 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
930 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
931 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
932 const CXXRecordDecl *BaseClassDecl) {
934 getContext().getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
935 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
936 CharUnits IntSize = getContext().getTypeSizeInChars(getContext().IntTy);
937 CharUnits VBTableChars =
939 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
940 llvm::Value *VBTableOffset =
941 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
943 llvm::Value *VBPtrToNewBase =
944 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
946 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
947 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
950 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
951 return isa<CXXConstructorDecl>(GD.getDecl());
954 static bool isDeletingDtor(GlobalDecl GD) {
955 return isa<CXXDestructorDecl>(GD.getDecl()) &&
956 GD.getDtorType() == Dtor_Deleting;
959 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
960 return isDeletingDtor(GD);
963 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
964 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
968 if (FI.isInstanceMethod()) {
969 // If it's an instance method, aggregates are always returned indirectly via
970 // the second parameter.
971 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
972 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
974 } else if (!RD->isPOD()) {
975 // If it's a free function, non-POD types are returned indirectly.
976 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
980 // Otherwise, use the C ABI rules.
985 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
986 const CXXRecordDecl *RD) {
987 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
988 assert(IsMostDerivedClass &&
989 "ctor for a class with virtual bases must have an implicit parameter");
990 llvm::Value *IsCompleteObject =
991 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
993 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
994 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
995 CGF.Builder.CreateCondBr(IsCompleteObject,
996 CallVbaseCtorsBB, SkipVbaseCtorsBB);
998 CGF.EmitBlock(CallVbaseCtorsBB);
1000 // Fill in the vbtable pointers here.
1001 EmitVBPtrStores(CGF, RD);
1003 // CGF will put the base ctor calls in this basic block for us later.
1005 return SkipVbaseCtorsBB;
1008 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1009 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1010 // In most cases, an override for a vbase virtual method can adjust
1011 // the "this" parameter by applying a constant offset.
1012 // However, this is not enough while a constructor or a destructor of some
1013 // class X is being executed if all the following conditions are met:
1014 // - X has virtual bases, (1)
1015 // - X overrides a virtual method M of a vbase Y, (2)
1016 // - X itself is a vbase of the most derived class.
1018 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1019 // which holds the extra amount of "this" adjustment we must do when we use
1020 // the X vftables (i.e. during X ctor or dtor).
1021 // Outside the ctors and dtors, the values of vtorDisps are zero.
1023 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1024 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1025 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1026 CGBuilderTy &Builder = CGF.Builder;
1029 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1030 llvm::Value *Int8This = nullptr; // Initialize lazily.
1032 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1034 if (!I->second.hasVtorDisp())
1037 llvm::Value *VBaseOffset =
1038 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1039 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1040 // just to Trunc back immediately.
1041 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1042 uint64_t ConstantVBaseOffset =
1043 Layout.getVBaseClassOffset(I->first).getQuantity();
1045 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1046 llvm::Value *VtorDispValue = Builder.CreateSub(
1047 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1051 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1052 CGF.Int8Ty->getPointerTo(AS));
1053 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1054 // vtorDisp is always the 32-bits before the vbase in the class layout.
1055 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1056 VtorDispPtr = Builder.CreateBitCast(
1057 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1059 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1063 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1064 // There's only one constructor type in this ABI.
1065 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1068 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1069 const CXXRecordDecl *RD) {
1070 llvm::Value *ThisInt8Ptr =
1071 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1072 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
1074 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1075 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1076 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1077 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1078 const ASTRecordLayout &SubobjectLayout =
1079 CGM.getContext().getASTRecordLayout(VBT->BaseWithVPtr);
1080 CharUnits Offs = VBT->NonVirtualOffset;
1081 Offs += SubobjectLayout.getVBPtrOffset();
1082 if (VBT->getVBaseWithVPtr())
1083 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1084 llvm::Value *VBPtr =
1085 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1086 llvm::Value *GVPtr = CGF.Builder.CreateConstInBoundsGEP2_32(GV, 0, 0);
1087 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1088 "vbptr." + VBT->ReusingBase->getName());
1089 CGF.Builder.CreateStore(GVPtr, VBPtr);
1094 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1095 SmallVectorImpl<CanQualType> &ArgTys) {
1096 // TODO: 'for base' flag
1097 if (T == StructorType::Deleting) {
1098 // The scalar deleting destructor takes an implicit int parameter.
1099 ArgTys.push_back(CGM.getContext().IntTy);
1101 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1105 // All parameters are already in place except is_most_derived, which goes
1106 // after 'this' if it's variadic and last if it's not.
1108 const CXXRecordDecl *Class = CD->getParent();
1109 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1110 if (Class->getNumVBases()) {
1111 if (FPT->isVariadic())
1112 ArgTys.insert(ArgTys.begin() + 1, CGM.getContext().IntTy);
1114 ArgTys.push_back(CGM.getContext().IntTy);
1118 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1119 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1120 // other destructor variants are delegating thunks.
1121 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1125 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1126 GD = GD.getCanonicalDecl();
1127 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1129 GlobalDecl LookupGD = GD;
1130 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1131 // Complete destructors take a pointer to the complete object as a
1132 // parameter, thus don't need this adjustment.
1133 if (GD.getDtorType() == Dtor_Complete)
1136 // There's no Dtor_Base in vftable but it shares the this adjustment with
1137 // the deleting one, so look it up instead.
1138 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1141 MicrosoftVTableContext::MethodVFTableLocation ML =
1142 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1143 CharUnits Adjustment = ML.VFPtrOffset;
1145 // Normal virtual instance methods need to adjust from the vfptr that first
1146 // defined the virtual method to the virtual base subobject, but destructors
1147 // do not. The vector deleting destructor thunk applies this adjustment for
1149 if (isa<CXXDestructorDecl>(MD))
1150 Adjustment = CharUnits::Zero();
1153 const ASTRecordLayout &DerivedLayout =
1154 CGM.getContext().getASTRecordLayout(MD->getParent());
1155 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1161 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1162 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1164 // If the call of a virtual function is not virtual, we just have to
1165 // compensate for the adjustment the virtual function does in its prologue.
1166 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1167 if (Adjustment.isZero())
1170 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1171 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1172 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1173 assert(Adjustment.isPositive());
1174 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1177 GD = GD.getCanonicalDecl();
1178 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1180 GlobalDecl LookupGD = GD;
1181 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1182 // Complete dtors take a pointer to the complete object,
1183 // thus don't need adjustment.
1184 if (GD.getDtorType() == Dtor_Complete)
1187 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1188 // with the base one, so look up the deleting one instead.
1189 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1191 MicrosoftVTableContext::MethodVFTableLocation ML =
1192 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1194 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1195 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1196 CharUnits StaticOffset = ML.VFPtrOffset;
1198 // Base destructors expect 'this' to point to the beginning of the base
1199 // subobject, not the first vfptr that happens to contain the virtual dtor.
1200 // However, we still need to apply the virtual base adjustment.
1201 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1202 StaticOffset = CharUnits::Zero();
1205 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1206 llvm::Value *VBaseOffset =
1207 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1208 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1210 if (!StaticOffset.isZero()) {
1211 assert(StaticOffset.isPositive());
1212 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1214 // Non-virtual adjustment might result in a pointer outside the allocated
1215 // object, e.g. if the final overrider class is laid out after the virtual
1216 // base that declares a method in the most derived class.
1217 // FIXME: Update the code that emits this adjustment in thunks prologues.
1218 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1220 This = CGF.Builder.CreateConstInBoundsGEP1_32(This,
1221 StaticOffset.getQuantity());
1227 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1229 FunctionArgList &Params) {
1230 ASTContext &Context = getContext();
1231 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1232 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1233 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1234 ImplicitParamDecl *IsMostDerived
1235 = ImplicitParamDecl::Create(Context, nullptr,
1236 CGF.CurGD.getDecl()->getLocation(),
1237 &Context.Idents.get("is_most_derived"),
1239 // The 'most_derived' parameter goes second if the ctor is variadic and last
1240 // if it's not. Dtors can't be variadic.
1241 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1242 if (FPT->isVariadic())
1243 Params.insert(Params.begin() + 1, IsMostDerived);
1245 Params.push_back(IsMostDerived);
1246 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1247 } else if (isDeletingDtor(CGF.CurGD)) {
1248 ImplicitParamDecl *ShouldDelete
1249 = ImplicitParamDecl::Create(Context, nullptr,
1250 CGF.CurGD.getDecl()->getLocation(),
1251 &Context.Idents.get("should_call_delete"),
1253 Params.push_back(ShouldDelete);
1254 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1258 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1259 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1260 // In this ABI, every virtual function takes a pointer to one of the
1261 // subobjects that first defines it as the 'this' parameter, rather than a
1262 // pointer to the final overrider subobject. Thus, we need to adjust it back
1263 // to the final overrider subobject before use.
1264 // See comments in the MicrosoftVFTableContext implementation for the details.
1265 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1266 if (Adjustment.isZero())
1269 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1270 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1271 *thisTy = This->getType();
1273 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1274 assert(Adjustment.isPositive());
1276 CGF.Builder.CreateConstInBoundsGEP1_32(This, -Adjustment.getQuantity());
1277 return CGF.Builder.CreateBitCast(This, thisTy);
1280 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1283 /// If this is a function that the ABI specifies returns 'this', initialize
1284 /// the return slot to 'this' at the start of the function.
1286 /// Unlike the setting of return types, this is done within the ABI
1287 /// implementation instead of by clients of CGCXXABI because:
1288 /// 1) getThisValue is currently protected
1289 /// 2) in theory, an ABI could implement 'this' returns some other way;
1290 /// HasThisReturn only specifies a contract, not the implementation
1291 if (HasThisReturn(CGF.CurGD))
1292 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1293 else if (hasMostDerivedReturn(CGF.CurGD))
1294 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1297 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1298 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1299 assert(getStructorImplicitParamDecl(CGF) &&
1300 "no implicit parameter for a constructor with virtual bases?");
1301 getStructorImplicitParamValue(CGF)
1302 = CGF.Builder.CreateLoad(
1303 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1307 if (isDeletingDtor(CGF.CurGD)) {
1308 assert(getStructorImplicitParamDecl(CGF) &&
1309 "no implicit parameter for a deleting destructor?");
1310 getStructorImplicitParamValue(CGF)
1311 = CGF.Builder.CreateLoad(
1312 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1313 "should_call_delete");
1317 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1318 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1319 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1320 assert(Type == Ctor_Complete || Type == Ctor_Base);
1322 // Check if we need a 'most_derived' parameter.
1323 if (!D->getParent()->getNumVBases())
1326 // Add the 'most_derived' argument second if we are variadic or last if not.
1327 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1328 llvm::Value *MostDerivedArg =
1329 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1330 RValue RV = RValue::get(MostDerivedArg);
1331 if (MostDerivedArg) {
1332 if (FPT->isVariadic())
1333 Args.insert(Args.begin() + 1,
1334 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1336 Args.add(RV, getContext().IntTy);
1339 return 1; // Added one arg.
1342 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1343 const CXXDestructorDecl *DD,
1344 CXXDtorType Type, bool ForVirtualBase,
1345 bool Delegating, llvm::Value *This) {
1346 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1348 if (DD->isVirtual()) {
1349 assert(Type != CXXDtorType::Dtor_Deleting &&
1350 "The deleting destructor should only be called via a virtual call");
1351 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1355 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1356 /*ImplicitParam=*/nullptr,
1357 /*ImplicitParamTy=*/QualType(), nullptr,
1358 getFromDtorType(Type));
1361 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1362 const CXXRecordDecl *RD) {
1363 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1364 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1366 for (VPtrInfo *Info : VFPtrs) {
1367 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1368 if (VTable->hasInitializer())
1371 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1372 ? getMSCompleteObjectLocator(RD, Info)
1375 const VTableLayout &VTLayout =
1376 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1377 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1378 RD, VTLayout.vtable_component_begin(),
1379 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1380 VTLayout.getNumVTableThunks(), RTTI);
1382 VTable->setInitializer(Init);
1386 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1387 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1388 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1389 NeedsVirtualOffset = (NearestVBase != nullptr);
1391 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1392 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1393 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1394 if (!VTableAddressPoint) {
1395 assert(Base.getBase()->getNumVBases() &&
1396 !CGM.getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1398 return VTableAddressPoint;
1401 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1402 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1403 SmallString<256> &Name) {
1404 llvm::raw_svector_ostream Out(Name);
1405 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1408 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1409 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1410 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1411 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1412 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1413 assert(VFTable && "Couldn't find a vftable for the given base?");
1417 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1418 CharUnits VPtrOffset) {
1419 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1420 // shouldn't be used in the given record type. We want to cache this result in
1421 // VFTablesMap, thus a simple zero check is not sufficient.
1422 VFTableIdTy ID(RD, VPtrOffset);
1423 VTablesMapTy::iterator I;
1425 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1429 llvm::GlobalVariable *&VTable = I->second;
1431 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1432 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1434 if (DeferredVFTables.insert(RD).second) {
1435 // We haven't processed this record type before.
1436 // Queue up this v-table for possible deferred emission.
1437 CGM.addDeferredVTable(RD);
1440 // Create all the vftables at once in order to make sure each vftable has
1441 // a unique mangled name.
1442 llvm::StringSet<> ObservedMangledNames;
1443 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1444 SmallString<256> Name;
1445 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1446 if (!ObservedMangledNames.insert(Name.str()).second)
1447 llvm_unreachable("Already saw this mangling before?");
1452 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1453 if (VFPtrs[J]->FullOffsetInMDC != VPtrOffset)
1455 SmallString<256> VFTableName;
1456 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], VFTableName);
1457 StringRef VTableName = VFTableName;
1459 uint64_t NumVTableSlots =
1460 VTContext.getVFTableLayout(RD, VFPtrs[J]->FullOffsetInMDC)
1461 .getNumVTableComponents();
1462 llvm::GlobalValue::LinkageTypes VTableLinkage =
1463 llvm::GlobalValue::ExternalLinkage;
1464 llvm::ArrayType *VTableType =
1465 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1466 if (getContext().getLangOpts().RTTIData) {
1467 VTableLinkage = llvm::GlobalValue::PrivateLinkage;
1471 VTable = CGM.getModule().getNamedGlobal(VFTableName);
1473 // Create a backing variable for the contents of VTable. The VTable may
1474 // or may not include space for a pointer to RTTI data.
1475 llvm::GlobalValue *VFTable = VTable = new llvm::GlobalVariable(
1476 CGM.getModule(), VTableType, /*isConstant=*/true, VTableLinkage,
1477 /*Initializer=*/nullptr, VTableName);
1478 VTable->setUnnamedAddr(true);
1480 // Only insert a pointer into the VFTable for RTTI data if we are not
1481 // importing it. We never reference the RTTI data directly so there is no
1482 // need to make room for it.
1483 if (getContext().getLangOpts().RTTIData &&
1484 !RD->hasAttr<DLLImportAttr>()) {
1485 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1486 llvm::ConstantInt::get(CGM.IntTy, 1)};
1487 // Create a GEP which points just after the first entry in the VFTable,
1488 // this should be the location of the first virtual method.
1489 llvm::Constant *VTableGEP =
1490 llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, GEPIndices);
1491 // The symbol for the VFTable is an alias to the GEP. It is
1492 // transparent, to other modules, what the nature of this symbol is; all
1493 // that matters is that the alias be the address of the first virtual
1495 VFTable = llvm::GlobalAlias::create(
1496 cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(),
1497 /*AddressSpace=*/0, llvm::GlobalValue::ExternalLinkage,
1498 VFTableName.str(), VTableGEP, &CGM.getModule());
1500 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1501 // be referencing any RTTI data. The GlobalVariable will end up being
1502 // an appropriate definition of the VFTable.
1503 VTable->setName(VFTableName.str());
1506 VFTable->setUnnamedAddr(true);
1507 if (RD->hasAttr<DLLImportAttr>())
1508 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1509 else if (RD->hasAttr<DLLExportAttr>())
1510 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1512 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1513 if (VFTable != VTable) {
1514 if (llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage)) {
1515 // AvailableExternally implies that we grabbed the data from another
1516 // executable. No need to stick the alias in a Comdat.
1517 } else if (llvm::GlobalValue::isInternalLinkage(VFTableLinkage) ||
1518 llvm::GlobalValue::isWeakODRLinkage(VFTableLinkage) ||
1519 llvm::GlobalValue::isLinkOnceODRLinkage(VFTableLinkage)) {
1520 // The alias is going to be dropped into a Comdat, no need to make it
1522 if (!llvm::GlobalValue::isInternalLinkage(VFTableLinkage))
1523 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1525 CGM.getModule().getOrInsertComdat(VFTable->getName());
1526 // We must indicate which VFTable is larger to support linking between
1527 // translation units which do and do not have RTTI data. The largest
1528 // VFTable contains the RTTI data; translation units which reference
1529 // the smaller VFTable always reference it relative to the first
1531 C->setSelectionKind(llvm::Comdat::Largest);
1532 VTable->setComdat(C);
1534 llvm_unreachable("unexpected linkage for vftable!");
1537 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage))
1539 CGM.getModule().getOrInsertComdat(VTable->getName()));
1541 VFTable->setLinkage(VFTableLinkage);
1542 CGM.setGlobalVisibility(VFTable, RD);
1543 VFTablesMap[ID] = VFTable;
1551 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1555 GD = GD.getCanonicalDecl();
1556 CGBuilderTy &Builder = CGF.Builder;
1558 Ty = Ty->getPointerTo()->getPointerTo();
1560 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1561 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1563 MicrosoftVTableContext::MethodVFTableLocation ML =
1564 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1565 llvm::Value *VFuncPtr =
1566 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1567 return Builder.CreateLoad(VFuncPtr);
1570 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1571 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1572 llvm::Value *This, const CXXMemberCallExpr *CE) {
1573 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1574 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1576 // We have only one destructor in the vftable but can get both behaviors
1577 // by passing an implicit int parameter.
1578 GlobalDecl GD(Dtor, Dtor_Deleting);
1579 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1580 Dtor, StructorType::Deleting);
1581 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1582 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1584 ASTContext &Context = CGF.getContext();
1585 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1586 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1587 DtorType == Dtor_Deleting);
1589 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1590 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1591 ImplicitParam, Context.IntTy, CE,
1592 StructorType::Deleting);
1593 return RV.getScalarVal();
1596 const VBTableGlobals &
1597 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1598 // At this layer, we can key the cache off of a single class, which is much
1599 // easier than caching each vbtable individually.
1600 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1602 std::tie(Entry, Added) =
1603 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1604 VBTableGlobals &VBGlobals = Entry->second;
1608 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1609 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1611 // Cache the globals for all vbtables so we don't have to recompute the
1613 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1614 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1615 E = VBGlobals.VBTables->end();
1617 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1623 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1624 const CXXMethodDecl *MD,
1625 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1626 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1627 "can't form pointers to ctors or virtual dtors");
1629 // Calculate the mangled name.
1630 SmallString<256> ThunkName;
1631 llvm::raw_svector_ostream Out(ThunkName);
1632 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1635 // If the thunk has been generated previously, just return it.
1636 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1637 return cast<llvm::Function>(GV);
1639 // Create the llvm::Function.
1640 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1641 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1642 llvm::Function *ThunkFn =
1643 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1644 ThunkName.str(), &CGM.getModule());
1645 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1647 ThunkFn->setLinkage(MD->isExternallyVisible()
1648 ? llvm::GlobalValue::LinkOnceODRLinkage
1649 : llvm::GlobalValue::InternalLinkage);
1650 if (MD->isExternallyVisible())
1651 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1653 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1654 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1656 // Add the "thunk" attribute so that LLVM knows that the return type is
1657 // meaningless. These thunks can be used to call functions with differing
1658 // return types, and the caller is required to cast the prototype
1659 // appropriately to extract the correct value.
1660 ThunkFn->addFnAttr("thunk");
1662 // These thunks can be compared, so they are not unnamed.
1663 ThunkFn->setUnnamedAddr(false);
1666 CodeGenFunction CGF(CGM);
1667 CGF.CurGD = GlobalDecl(MD);
1668 CGF.CurFuncIsThunk = true;
1670 // Build FunctionArgs, but only include the implicit 'this' parameter
1672 FunctionArgList FunctionArgs;
1673 buildThisParam(CGF, FunctionArgs);
1675 // Start defining the function.
1676 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1677 FunctionArgs, MD->getLocation(), SourceLocation());
1680 // Load the vfptr and then callee from the vftable. The callee should have
1681 // adjusted 'this' so that the vfptr is at offset zero.
1682 llvm::Value *VTable = CGF.GetVTablePtr(
1683 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1684 llvm::Value *VFuncPtr =
1685 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1686 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1688 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1693 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1694 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1695 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1696 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1697 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1698 if (GV->isDeclaration())
1699 emitVBTableDefinition(*VBT, RD, GV);
1703 llvm::GlobalVariable *
1704 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1705 llvm::GlobalVariable::LinkageTypes Linkage) {
1706 SmallString<256> OutName;
1707 llvm::raw_svector_ostream Out(OutName);
1708 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1710 StringRef Name = OutName.str();
1712 llvm::ArrayType *VBTableType =
1713 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1715 assert(!CGM.getModule().getNamedGlobal(Name) &&
1716 "vbtable with this name already exists: mangling bug?");
1717 llvm::GlobalVariable *GV =
1718 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1719 GV->setUnnamedAddr(true);
1721 if (RD->hasAttr<DLLImportAttr>())
1722 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1723 else if (RD->hasAttr<DLLExportAttr>())
1724 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1726 if (!GV->hasExternalLinkage())
1727 emitVBTableDefinition(VBT, RD, GV);
1732 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1733 const CXXRecordDecl *RD,
1734 llvm::GlobalVariable *GV) const {
1735 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1737 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1738 "should only emit vbtables for classes with vbtables");
1740 const ASTRecordLayout &BaseLayout =
1741 CGM.getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1742 const ASTRecordLayout &DerivedLayout =
1743 CGM.getContext().getASTRecordLayout(RD);
1745 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1748 // The offset from ReusingBase's vbptr to itself always leads.
1749 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1750 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1752 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1753 for (const auto &I : ReusingBase->vbases()) {
1754 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1755 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1756 assert(!Offset.isNegative());
1758 // Make it relative to the subobject vbptr.
1759 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1760 if (VBT.getVBaseWithVPtr())
1761 CompleteVBPtrOffset +=
1762 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1763 Offset -= CompleteVBPtrOffset;
1765 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1766 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1767 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1770 assert(Offsets.size() ==
1771 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1772 ->getElementType())->getNumElements());
1773 llvm::ArrayType *VBTableType =
1774 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1775 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1776 GV->setInitializer(Init);
1778 // Set the right visibility.
1779 CGM.setGlobalVisibility(GV, RD);
1782 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1784 const ThisAdjustment &TA) {
1788 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1790 if (!TA.Virtual.isEmpty()) {
1791 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1792 // Adjust the this argument based on the vtordisp value.
1793 llvm::Value *VtorDispPtr =
1794 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1796 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1797 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1798 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1800 if (TA.Virtual.Microsoft.VBPtrOffset) {
1801 // If the final overrider is defined in a virtual base other than the one
1802 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1803 // the vbtable of the derived class.
1804 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1805 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1807 llvm::Value *VBaseOffset =
1808 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1809 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1810 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1814 if (TA.NonVirtual) {
1815 // Non-virtual adjustment might result in a pointer outside the allocated
1816 // object, e.g. if the final overrider class is laid out after the virtual
1817 // base that declares a method in the most derived class.
1818 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1821 // Don't need to bitcast back, the call CodeGen will handle this.
1826 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1827 const ReturnAdjustment &RA) {
1831 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1833 if (RA.Virtual.Microsoft.VBIndex) {
1834 assert(RA.Virtual.Microsoft.VBIndex > 0);
1836 getContext().getTypeSizeInChars(getContext().IntTy).getQuantity();
1838 llvm::Value *VBaseOffset =
1839 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1840 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1841 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1845 V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual);
1847 // Cast back to the original type.
1848 return CGF.Builder.CreateBitCast(V, Ret->getType());
1851 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1852 QualType elementType) {
1853 // Microsoft seems to completely ignore the possibility of a
1854 // two-argument usual deallocation function.
1855 return elementType.isDestructedType();
1858 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1859 // Microsoft seems to completely ignore the possibility of a
1860 // two-argument usual deallocation function.
1861 return expr->getAllocatedType().isDestructedType();
1864 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1865 // The array cookie is always a size_t; we then pad that out to the
1866 // alignment of the element type.
1867 ASTContext &Ctx = getContext();
1868 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1869 Ctx.getTypeAlignInChars(type));
1872 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1873 llvm::Value *allocPtr,
1874 CharUnits cookieSize) {
1875 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1876 llvm::Value *numElementsPtr =
1877 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1878 return CGF.Builder.CreateLoad(numElementsPtr);
1881 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1882 llvm::Value *newPtr,
1883 llvm::Value *numElements,
1884 const CXXNewExpr *expr,
1885 QualType elementType) {
1886 assert(requiresArrayCookie(expr));
1888 // The size of the cookie.
1889 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1891 // Compute an offset to the cookie.
1892 llvm::Value *cookiePtr = newPtr;
1894 // Write the number of elements into the appropriate slot.
1895 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1896 llvm::Value *numElementsPtr
1897 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1898 CGF.Builder.CreateStore(numElements, numElementsPtr);
1900 // Finally, compute a pointer to the actual data buffer by skipping
1901 // over the cookie completely.
1902 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1903 cookieSize.getQuantity());
1906 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
1907 llvm::Constant *Dtor,
1908 llvm::Constant *Addr) {
1909 // Create a function which calls the destructor.
1910 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
1912 // extern "C" int __tlregdtor(void (*f)(void));
1913 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
1914 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
1916 llvm::Constant *TLRegDtor =
1917 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
1918 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
1919 TLRegDtorFn->setDoesNotThrow();
1921 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
1924 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
1925 llvm::Constant *Dtor,
1926 llvm::Constant *Addr) {
1928 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
1930 // The default behavior is to use atexit.
1931 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
1934 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
1936 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
1938 ArrayRef<llvm::Function *> CXXThreadLocalInits,
1939 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
1940 // This will create a GV in the .CRT$XDU section. It will point to our
1941 // initialization function. The CRT will call all of these function
1942 // pointers at start-up time and, eventually, at thread-creation time.
1943 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
1944 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
1945 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
1946 llvm::GlobalVariable::InternalLinkage, InitFunc,
1947 Twine(InitFunc->getName(), "$initializer$"));
1948 InitFuncPtr->setSection(".CRT$XDU");
1949 // This variable has discardable linkage, we have to add it to @llvm.used to
1950 // ensure it won't get discarded.
1951 CGM.addUsedGlobal(InitFuncPtr);
1955 std::vector<llvm::Function *> NonComdatInits;
1956 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
1957 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
1958 llvm::Function *F = CXXThreadLocalInits[I];
1960 // If the GV is already in a comdat group, then we have to join it.
1961 if (llvm::Comdat *C = GV->getComdat())
1962 AddToXDU(F)->setComdat(C);
1964 NonComdatInits.push_back(F);
1967 if (!NonComdatInits.empty()) {
1968 llvm::FunctionType *FTy =
1969 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
1970 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
1971 FTy, "__tls_init", SourceLocation(),
1973 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
1979 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
1981 QualType LValType) {
1982 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
1986 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
1987 llvm::GlobalVariable *GV,
1989 // MSVC only uses guards for static locals.
1990 if (!D.isStaticLocal()) {
1991 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
1992 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
1993 llvm::Function *F = CGF.CurFn;
1994 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
1995 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
1996 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2000 // MSVC always uses an i32 bitfield to guard initialization, which is *not*
2001 // threadsafe. Since the user may be linking in inline functions compiled by
2002 // cl.exe, there's no reason to provide a false sense of security by using
2003 // critical sections here.
2006 CGM.ErrorUnsupported(&D, "dynamic TLS initialization");
2008 CGBuilderTy &Builder = CGF.Builder;
2009 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2010 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2012 // Get the guard variable for this function if we have one already.
2013 GuardInfo *GI = &GuardVariableMap[D.getDeclContext()];
2016 if (D.isStaticLocal() && D.isExternallyVisible()) {
2017 // Externally visible variables have to be numbered in Sema to properly
2018 // handle unreachable VarDecls.
2019 BitIndex = getContext().getStaticLocalNumber(&D);
2020 assert(BitIndex > 0);
2023 // Non-externally visible variables are numbered here in CodeGen.
2024 BitIndex = GI->BitIndex++;
2027 if (BitIndex >= 32) {
2028 if (D.isExternallyVisible())
2029 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2031 GI->Guard = nullptr;
2034 // Lazily create the i32 bitfield for this function.
2036 // Mangle the name for the guard.
2037 SmallString<256> GuardName;
2039 llvm::raw_svector_ostream Out(GuardName);
2040 getMangleContext().mangleStaticGuardVariable(&D, Out);
2044 // Create the guard variable with a zero-initializer. Just absorb linkage,
2045 // visibility and dll storage class from the guarded variable.
2047 new llvm::GlobalVariable(CGM.getModule(), GuardTy, false,
2048 GV->getLinkage(), Zero, GuardName.str());
2049 GI->Guard->setVisibility(GV->getVisibility());
2050 GI->Guard->setDLLStorageClass(GV->getDLLStorageClass());
2051 if (GI->Guard->isWeakForLinker())
2052 GI->Guard->setComdat(
2053 CGM.getModule().getOrInsertComdat(GI->Guard->getName()));
2055 assert(GI->Guard->getLinkage() == GV->getLinkage() &&
2056 "static local from the same function had different linkage");
2059 // Pseudo code for the test:
2060 // if (!(GuardVar & MyGuardBit)) {
2061 // GuardVar |= MyGuardBit;
2062 // ... initialize the object ...;
2065 // Test our bit from the guard variable.
2066 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << BitIndex);
2067 llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard);
2068 llvm::Value *IsInitialized =
2069 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2070 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2071 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2072 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2074 // Set our bit in the guard variable and emit the initializer and add a global
2075 // destructor if appropriate.
2076 CGF.EmitBlock(InitBlock);
2077 Builder.CreateStore(Builder.CreateOr(LI, Bit), GI->Guard);
2078 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2079 Builder.CreateBr(EndBlock);
2082 CGF.EmitBlock(EndBlock);
2085 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2086 // Null-ness for function memptrs only depends on the first field, which is
2087 // the function pointer. The rest don't matter, so we can zero initialize.
2088 if (MPT->isMemberFunctionPointer())
2091 // The virtual base adjustment field is always -1 for null, so if we have one
2092 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2093 // valid field offset.
2094 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2095 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2096 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2097 RD->nullFieldOffsetIsZero());
2101 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2102 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2103 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2104 llvm::SmallVector<llvm::Type *, 4> fields;
2105 if (MPT->isMemberFunctionPointer())
2106 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2108 fields.push_back(CGM.IntTy); // FieldOffset
2110 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2112 fields.push_back(CGM.IntTy);
2113 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2114 fields.push_back(CGM.IntTy);
2115 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2116 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2118 if (fields.size() == 1)
2120 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2123 void MicrosoftCXXABI::
2124 GetNullMemberPointerFields(const MemberPointerType *MPT,
2125 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2126 assert(fields.empty());
2127 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2128 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2129 if (MPT->isMemberFunctionPointer()) {
2130 // FunctionPointerOrVirtualThunk
2131 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2133 if (RD->nullFieldOffsetIsZero())
2134 fields.push_back(getZeroInt()); // FieldOffset
2136 fields.push_back(getAllOnesInt()); // FieldOffset
2139 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2141 fields.push_back(getZeroInt());
2142 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2143 fields.push_back(getZeroInt());
2144 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2145 fields.push_back(getAllOnesInt());
2149 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2150 llvm::SmallVector<llvm::Constant *, 4> fields;
2151 GetNullMemberPointerFields(MPT, fields);
2152 if (fields.size() == 1)
2154 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2155 assert(Res->getType() == ConvertMemberPointerType(MPT));
2160 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2161 bool IsMemberFunction,
2162 const CXXRecordDecl *RD,
2163 CharUnits NonVirtualBaseAdjustment)
2165 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2167 // Single inheritance class member pointer are represented as scalars instead
2169 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2172 llvm::SmallVector<llvm::Constant *, 4> fields;
2173 fields.push_back(FirstField);
2175 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2176 fields.push_back(llvm::ConstantInt::get(
2177 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2179 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2180 CharUnits Offs = CharUnits::Zero();
2181 if (RD->getNumVBases())
2182 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2183 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2186 // The rest of the fields are adjusted by conversions to a more derived class.
2187 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2188 fields.push_back(getZeroInt());
2190 return llvm::ConstantStruct::getAnon(fields);
2194 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2196 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2197 llvm::Constant *FirstField =
2198 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2199 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2203 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
2204 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
2207 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2209 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
2210 const ValueDecl *MPD = MP.getMemberPointerDecl();
2212 return EmitNullMemberPointer(MPT);
2214 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
2216 // FIXME PR15713: Support virtual inheritance paths.
2218 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
2219 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
2222 CharUnits FieldOffset =
2223 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
2224 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
2228 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
2229 const CXXMethodDecl *MD,
2230 CharUnits NonVirtualBaseAdjustment) {
2231 assert(MD->isInstance() && "Member function must not be static!");
2232 MD = MD->getCanonicalDecl();
2233 RD = RD->getMostRecentDecl();
2234 CodeGenTypes &Types = CGM.getTypes();
2236 llvm::Constant *FirstField;
2237 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2238 if (!MD->isVirtual()) {
2240 // Check whether the function has a computable LLVM signature.
2241 if (Types.isFuncTypeConvertible(FPT)) {
2242 // The function has a computable LLVM signature; use the correct type.
2243 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2245 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2246 // function type is incomplete.
2249 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2250 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2252 MicrosoftVTableContext::MethodVFTableLocation ML =
2253 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
2254 if (!CGM.getTypes().isFuncTypeConvertible(
2255 MD->getType()->castAs<FunctionType>())) {
2256 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
2257 "incomplete return or parameter type");
2258 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2259 } else if (FPT->getCallConv() == CC_X86FastCall) {
2260 CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
2261 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2262 } else if (ML.VBase) {
2263 CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding "
2264 "member function in virtual base class");
2265 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2267 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2268 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2269 // Include the vfptr adjustment if the method is in a non-primary vftable.
2270 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2274 // The rest of the fields are common with data member pointers.
2275 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2276 NonVirtualBaseAdjustment);
2279 /// Member pointers are the same if they're either bitwise identical *or* both
2280 /// null. Null-ness for function members is determined by the first field,
2281 /// while for data member pointers we must compare all fields.
2283 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2286 const MemberPointerType *MPT,
2288 CGBuilderTy &Builder = CGF.Builder;
2290 // Handle != comparisons by switching the sense of all boolean operations.
2291 llvm::ICmpInst::Predicate Eq;
2292 llvm::Instruction::BinaryOps And, Or;
2294 Eq = llvm::ICmpInst::ICMP_NE;
2295 And = llvm::Instruction::Or;
2296 Or = llvm::Instruction::And;
2298 Eq = llvm::ICmpInst::ICMP_EQ;
2299 And = llvm::Instruction::And;
2300 Or = llvm::Instruction::Or;
2303 // If this is a single field member pointer (single inheritance), this is a
2305 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2306 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2307 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2309 return Builder.CreateICmp(Eq, L, R);
2311 // Compare the first field.
2312 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2313 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2314 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2316 // Compare everything other than the first field.
2317 llvm::Value *Res = nullptr;
2318 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2319 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2320 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2321 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2322 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2324 Res = Builder.CreateBinOp(And, Res, Cmp);
2329 // Check if the first field is 0 if this is a function pointer.
2330 if (MPT->isMemberFunctionPointer()) {
2331 // (l1 == r1 && ...) || l0 == 0
2332 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2333 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2334 Res = Builder.CreateBinOp(Or, Res, IsZero);
2337 // Combine the comparison of the first field, which must always be true for
2338 // this comparison to succeeed.
2339 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2343 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2344 llvm::Value *MemPtr,
2345 const MemberPointerType *MPT) {
2346 CGBuilderTy &Builder = CGF.Builder;
2347 llvm::SmallVector<llvm::Constant *, 4> fields;
2348 // We only need one field for member functions.
2349 if (MPT->isMemberFunctionPointer())
2350 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2352 GetNullMemberPointerFields(MPT, fields);
2353 assert(!fields.empty());
2354 llvm::Value *FirstField = MemPtr;
2355 if (MemPtr->getType()->isStructTy())
2356 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2357 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2359 // For function member pointers, we only need to test the function pointer
2360 // field. The other fields if any can be garbage.
2361 if (MPT->isMemberFunctionPointer())
2364 // Otherwise, emit a series of compares and combine the results.
2365 for (int I = 1, E = fields.size(); I < E; ++I) {
2366 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2367 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2368 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2373 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2374 llvm::Constant *Val) {
2375 // Function pointers are null if the pointer in the first field is null.
2376 if (MPT->isMemberFunctionPointer()) {
2377 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2378 Val->getAggregateElement(0U) : Val;
2379 return FirstField->isNullValue();
2382 // If it's not a function pointer and it's zero initializable, we can easily
2384 if (isZeroInitializable(MPT) && Val->isNullValue())
2387 // Otherwise, break down all the fields for comparison. Hopefully these
2388 // little Constants are reused, while a big null struct might not be.
2389 llvm::SmallVector<llvm::Constant *, 4> Fields;
2390 GetNullMemberPointerFields(MPT, Fields);
2391 if (Fields.size() == 1) {
2392 assert(Val->getType()->isIntegerTy());
2393 return Val == Fields[0];
2397 for (I = 0, E = Fields.size(); I != E; ++I) {
2398 if (Val->getAggregateElement(I) != Fields[I])
2405 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2407 llvm::Value *VBPtrOffset,
2408 llvm::Value *VBTableOffset,
2409 llvm::Value **VBPtrOut) {
2410 CGBuilderTy &Builder = CGF.Builder;
2411 // Load the vbtable pointer from the vbptr in the instance.
2412 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2413 llvm::Value *VBPtr =
2414 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2415 if (VBPtrOut) *VBPtrOut = VBPtr;
2416 VBPtr = Builder.CreateBitCast(VBPtr,
2417 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2418 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2420 // Translate from byte offset to table index. It improves analyzability.
2421 llvm::Value *VBTableIndex = Builder.CreateAShr(
2422 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2423 "vbtindex", /*isExact=*/true);
2425 // Load an i32 offset from the vb-table.
2426 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2427 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2428 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2431 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2433 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2434 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2435 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2436 CGBuilderTy &Builder = CGF.Builder;
2437 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2438 llvm::BasicBlock *OriginalBB = nullptr;
2439 llvm::BasicBlock *SkipAdjustBB = nullptr;
2440 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2442 // In the unspecified inheritance model, there might not be a vbtable at all,
2443 // in which case we need to skip the virtual base lookup. If there is a
2444 // vbtable, the first entry is a no-op entry that gives back the original
2445 // base, so look for a virtual base adjustment offset of zero.
2447 OriginalBB = Builder.GetInsertBlock();
2448 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2449 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2450 llvm::Value *IsVirtual =
2451 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2453 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2454 CGF.EmitBlock(VBaseAdjustBB);
2457 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2458 // know the vbptr offset.
2460 CharUnits offs = CharUnits::Zero();
2461 if (!RD->hasDefinition()) {
2462 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2463 unsigned DiagID = Diags.getCustomDiagID(
2464 DiagnosticsEngine::Error,
2465 "member pointer representation requires a "
2466 "complete class type for %0 to perform this expression");
2467 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2468 } else if (RD->getNumVBases())
2469 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2470 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2472 llvm::Value *VBPtr = nullptr;
2473 llvm::Value *VBaseOffs =
2474 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2475 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2477 // Merge control flow with the case where we didn't have to adjust.
2478 if (VBaseAdjustBB) {
2479 Builder.CreateBr(SkipAdjustBB);
2480 CGF.EmitBlock(SkipAdjustBB);
2481 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2482 Phi->addIncoming(Base, OriginalBB);
2483 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2486 return AdjustedBase;
2489 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2490 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2491 const MemberPointerType *MPT) {
2492 assert(MPT->isMemberDataPointer());
2493 unsigned AS = Base->getType()->getPointerAddressSpace();
2495 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2496 CGBuilderTy &Builder = CGF.Builder;
2497 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2498 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2500 // Extract the fields we need, regardless of model. We'll apply them if we
2502 llvm::Value *FieldOffset = MemPtr;
2503 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2504 llvm::Value *VBPtrOffset = nullptr;
2505 if (MemPtr->getType()->isStructTy()) {
2506 // We need to extract values.
2508 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2509 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2510 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2511 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2512 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2515 if (VirtualBaseAdjustmentOffset) {
2516 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2521 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2523 // Apply the offset, which we assume is non-null.
2525 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2527 // Cast the address to the appropriate pointer type, adopting the address
2528 // space of the base pointer.
2529 return Builder.CreateBitCast(Addr, PType);
2532 static MSInheritanceAttr::Spelling
2533 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2534 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2538 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2541 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2542 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2543 E->getCastKind() == CK_ReinterpretMemberPointer);
2545 // Use constant emission if we can.
2546 if (isa<llvm::Constant>(Src))
2547 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2549 // We may be adding or dropping fields from the member pointer, so we need
2550 // both types and the inheritance models of both records.
2551 const MemberPointerType *SrcTy =
2552 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2553 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2554 bool IsFunc = SrcTy->isMemberFunctionPointer();
2556 // If the classes use the same null representation, reinterpret_cast is a nop.
2557 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2558 if (IsReinterpret && IsFunc)
2561 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2562 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2563 if (IsReinterpret &&
2564 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2567 CGBuilderTy &Builder = CGF.Builder;
2569 // Branch past the conversion if Src is null.
2570 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2571 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2573 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2574 // pointer value of the destination type.
2575 if (IsReinterpret) {
2576 // For reinterpret casts, sema ensures that src and dst are both functions
2577 // or data and have the same size, which means the LLVM types should match.
2578 assert(Src->getType() == DstNull->getType());
2579 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2582 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2583 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2584 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2585 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2586 CGF.EmitBlock(ConvertBB);
2589 llvm::Value *FirstField = Src;
2590 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2591 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2592 llvm::Value *VBPtrOffset = nullptr;
2593 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2594 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2595 // We need to extract values.
2597 FirstField = Builder.CreateExtractValue(Src, I++);
2598 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2599 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2600 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2601 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2602 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2603 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2606 // For data pointers, we adjust the field offset directly. For functions, we
2607 // have a separate field.
2608 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2610 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2611 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2612 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2613 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2614 NVAdjustField = getZeroInt();
2615 if (isDerivedToBase)
2616 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2618 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2621 // FIXME PR15713: Support conversions through virtually derived classes.
2623 // Recompose dst from the null struct and the adjusted fields from src.
2624 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2626 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2629 Dst = llvm::UndefValue::get(DstNull->getType());
2631 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2632 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2633 Dst = Builder.CreateInsertValue(
2634 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2635 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2636 Dst = Builder.CreateInsertValue(
2637 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2638 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2639 Dst = Builder.CreateInsertValue(
2640 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2642 Builder.CreateBr(ContinueBB);
2644 // In the continuation, choose between DstNull and Dst.
2645 CGF.EmitBlock(ContinueBB);
2646 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2647 Phi->addIncoming(DstNull, OriginalBB);
2648 Phi->addIncoming(Dst, ConvertBB);
2653 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2654 llvm::Constant *Src) {
2655 const MemberPointerType *SrcTy =
2656 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2657 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2659 // If src is null, emit a new null for dst. We can't return src because dst
2660 // might have a new representation.
2661 if (MemberPointerConstantIsNull(SrcTy, Src))
2662 return EmitNullMemberPointer(DstTy);
2664 // We don't need to do anything for reinterpret_casts of non-null member
2665 // pointers. We should only get here when the two type representations have
2667 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2670 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2671 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2674 llvm::Constant *FirstField = Src;
2675 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2676 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2677 llvm::Constant *VBPtrOffset = nullptr;
2678 bool IsFunc = SrcTy->isMemberFunctionPointer();
2679 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2680 // We need to extract values.
2682 FirstField = Src->getAggregateElement(I++);
2683 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2684 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2685 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2686 VBPtrOffset = Src->getAggregateElement(I++);
2687 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2688 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2691 // For data pointers, we adjust the field offset directly. For functions, we
2692 // have a separate field.
2693 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2695 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2696 llvm::Constant *&NVAdjustField =
2697 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2698 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2699 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2700 NVAdjustField = getZeroInt();
2701 if (IsDerivedToBase)
2702 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2704 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2707 // FIXME PR15713: Support conversions through virtually derived classes.
2709 // Recompose dst from the null struct and the adjusted fields from src.
2710 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2713 llvm::SmallVector<llvm::Constant *, 4> Fields;
2714 Fields.push_back(FirstField);
2715 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2716 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2717 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2718 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2719 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2720 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2721 return llvm::ConstantStruct::getAnon(Fields);
2724 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2725 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2726 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2727 assert(MPT->isMemberFunctionPointer());
2728 const FunctionProtoType *FPT =
2729 MPT->getPointeeType()->castAs<FunctionProtoType>();
2730 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2731 llvm::FunctionType *FTy =
2732 CGM.getTypes().GetFunctionType(
2733 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2734 CGBuilderTy &Builder = CGF.Builder;
2736 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2738 // Extract the fields we need, regardless of model. We'll apply them if we
2740 llvm::Value *FunctionPointer = MemPtr;
2741 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2742 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2743 llvm::Value *VBPtrOffset = nullptr;
2744 if (MemPtr->getType()->isStructTy()) {
2745 // We need to extract values.
2747 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2748 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2749 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2750 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2751 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2752 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2753 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2756 if (VirtualBaseAdjustmentOffset) {
2757 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2761 if (NonVirtualBaseAdjustment) {
2762 // Apply the adjustment and cast back to the original struct type.
2763 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2764 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2765 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2768 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2771 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2772 return new MicrosoftCXXABI(CGM);
2775 // MS RTTI Overview:
2776 // The run time type information emitted by cl.exe contains 5 distinct types of
2777 // structures. Many of them reference each other.
2779 // TypeInfo: Static classes that are returned by typeid.
2781 // CompleteObjectLocator: Referenced by vftables. They contain information
2782 // required for dynamic casting, including OffsetFromTop. They also contain
2783 // a reference to the TypeInfo for the type and a reference to the
2784 // CompleteHierarchyDescriptor for the type.
2786 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2787 // Used during dynamic_cast to walk a class hierarchy. References a base
2788 // class array and the size of said array.
2790 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2791 // somewhat of a misnomer because the most derived class is also in the list
2792 // as well as multiple copies of virtual bases (if they occur multiple times
2793 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2794 // every path in the hierarchy, in pre-order depth first order. Note, we do
2795 // not declare a specific llvm type for BaseClassArray, it's merely an array
2796 // of BaseClassDescriptor pointers.
2798 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2799 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2800 // BaseClassArray is. It contains information about a class within a
2801 // hierarchy such as: is this base is ambiguous and what is its offset in the
2802 // vbtable. The names of the BaseClassDescriptors have all of their fields
2803 // mangled into them so they can be aggressively deduplicated by the linker.
2805 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2806 StringRef MangledName("\01??_7type_info@@6B@");
2807 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2809 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2811 llvm::GlobalVariable::ExternalLinkage,
2812 /*Initializer=*/nullptr, MangledName);
2817 /// \brief A Helper struct that stores information about a class in a class
2818 /// hierarchy. The information stored in these structs struct is used during
2819 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2820 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2821 // implicit depth first pre-order tree connectivity. getFirstChild and
2822 // getNextSibling allow us to walk the tree efficiently.
2823 struct MSRTTIClass {
2825 IsPrivateOnPath = 1 | 8,
2829 HasHierarchyDescriptor = 64
2831 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
2832 uint32_t initialize(const MSRTTIClass *Parent,
2833 const CXXBaseSpecifier *Specifier);
2835 MSRTTIClass *getFirstChild() { return this + 1; }
2836 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
2837 return Child + 1 + Child->NumBases;
2840 const CXXRecordDecl *RD, *VirtualRoot;
2841 uint32_t Flags, NumBases, OffsetInVBase;
2844 /// \brief Recursively initialize the base class array.
2845 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
2846 const CXXBaseSpecifier *Specifier) {
2847 Flags = HasHierarchyDescriptor;
2849 VirtualRoot = nullptr;
2852 if (Specifier->getAccessSpecifier() != AS_public)
2853 Flags |= IsPrivate | IsPrivateOnPath;
2854 if (Specifier->isVirtual()) {
2859 if (Parent->Flags & IsPrivateOnPath)
2860 Flags |= IsPrivateOnPath;
2861 VirtualRoot = Parent->VirtualRoot;
2862 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
2863 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
2867 MSRTTIClass *Child = getFirstChild();
2868 for (const CXXBaseSpecifier &Base : RD->bases()) {
2869 NumBases += Child->initialize(this, &Base) + 1;
2870 Child = getNextChild(Child);
2875 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
2876 switch (Ty->getLinkage()) {
2878 case InternalLinkage:
2879 case UniqueExternalLinkage:
2880 return llvm::GlobalValue::InternalLinkage;
2882 case VisibleNoLinkage:
2883 case ExternalLinkage:
2884 return llvm::GlobalValue::LinkOnceODRLinkage;
2886 llvm_unreachable("Invalid linkage!");
2889 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
2890 /// calls to the module and information about the most derived class in a
2892 struct MSRTTIBuilder {
2894 HasBranchingHierarchy = 1,
2895 HasVirtualBranchingHierarchy = 2,
2896 HasAmbiguousBases = 4
2899 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
2900 : CGM(ABI.CGM), Context(CGM.getContext()),
2901 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
2902 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
2905 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
2906 llvm::GlobalVariable *
2907 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
2908 llvm::GlobalVariable *getClassHierarchyDescriptor();
2909 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
2912 ASTContext &Context;
2913 llvm::LLVMContext &VMContext;
2914 llvm::Module &Module;
2915 const CXXRecordDecl *RD;
2916 llvm::GlobalVariable::LinkageTypes Linkage;
2917 MicrosoftCXXABI &ABI;
2922 /// \brief Recursively serializes a class hierarchy in pre-order depth first
2924 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
2925 const CXXRecordDecl *RD) {
2926 Classes.push_back(MSRTTIClass(RD));
2927 for (const CXXBaseSpecifier &Base : RD->bases())
2928 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
2931 /// \brief Find ambiguity among base classes.
2933 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
2934 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
2935 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
2936 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
2937 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
2938 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
2939 !VirtualBases.insert(Class->RD).second) {
2940 Class = MSRTTIClass::getNextChild(Class);
2943 if (!UniqueBases.insert(Class->RD).second)
2944 AmbiguousBases.insert(Class->RD);
2947 if (AmbiguousBases.empty())
2949 for (MSRTTIClass &Class : Classes)
2950 if (AmbiguousBases.count(Class.RD))
2951 Class.Flags |= MSRTTIClass::IsAmbiguous;
2954 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
2955 SmallString<256> MangledName;
2957 llvm::raw_svector_ostream Out(MangledName);
2958 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
2961 // Check to see if we've already declared this ClassHierarchyDescriptor.
2962 if (auto CHD = Module.getNamedGlobal(MangledName))
2965 // Serialize the class hierarchy and initialize the CHD Fields.
2966 SmallVector<MSRTTIClass, 8> Classes;
2967 serializeClassHierarchy(Classes, RD);
2968 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
2969 detectAmbiguousBases(Classes);
2971 for (auto Class : Classes) {
2972 if (Class.RD->getNumBases() > 1)
2973 Flags |= HasBranchingHierarchy;
2974 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
2975 // believe the field isn't actually used.
2976 if (Class.Flags & MSRTTIClass::IsAmbiguous)
2977 Flags |= HasAmbiguousBases;
2979 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
2980 Flags |= HasVirtualBranchingHierarchy;
2981 // These gep indices are used to get the address of the first element of the
2982 // base class array.
2983 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
2984 llvm::ConstantInt::get(CGM.IntTy, 0)};
2986 // Forward-declare the class hierarchy descriptor
2987 auto Type = ABI.getClassHierarchyDescriptorType();
2988 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
2989 /*Initializer=*/nullptr,
2990 StringRef(MangledName));
2991 if (CHD->isWeakForLinker())
2992 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
2994 // Initialize the base class ClassHierarchyDescriptor.
2995 llvm::Constant *Fields[] = {
2996 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
2997 llvm::ConstantInt::get(CGM.IntTy, Flags),
2998 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
2999 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3000 getBaseClassArray(Classes),
3001 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3003 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3007 llvm::GlobalVariable *
3008 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3009 SmallString<256> MangledName;
3011 llvm::raw_svector_ostream Out(MangledName);
3012 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3015 // Forward-declare the base class array.
3016 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3017 // mode) bytes of padding. We provide a pointer sized amount of padding by
3018 // adding +1 to Classes.size(). The sections have pointer alignment and are
3019 // marked pick-any so it shouldn't matter.
3020 llvm::Type *PtrType = ABI.getImageRelativeType(
3021 ABI.getBaseClassDescriptorType()->getPointerTo());
3022 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3024 new llvm::GlobalVariable(Module, ArrType,
3025 /*Constant=*/true, Linkage,
3026 /*Initializer=*/nullptr, StringRef(MangledName));
3027 if (BCA->isWeakForLinker())
3028 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3030 // Initialize the BaseClassArray.
3031 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3032 for (MSRTTIClass &Class : Classes)
3033 BaseClassArrayData.push_back(
3034 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3035 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3036 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3040 llvm::GlobalVariable *
3041 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3042 // Compute the fields for the BaseClassDescriptor. They are computed up front
3043 // because they are mangled into the name of the object.
3044 uint32_t OffsetInVBTable = 0;
3045 int32_t VBPtrOffset = -1;
3046 if (Class.VirtualRoot) {
3047 auto &VTableContext = CGM.getMicrosoftVTableContext();
3048 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3049 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3052 SmallString<256> MangledName;
3054 llvm::raw_svector_ostream Out(MangledName);
3055 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3056 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3060 // Check to see if we've already declared this object.
3061 if (auto BCD = Module.getNamedGlobal(MangledName))
3064 // Forward-declare the base class descriptor.
3065 auto Type = ABI.getBaseClassDescriptorType();
3067 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3068 /*Initializer=*/nullptr, StringRef(MangledName));
3069 if (BCD->isWeakForLinker())
3070 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3072 // Initialize the BaseClassDescriptor.
3073 llvm::Constant *Fields[] = {
3074 ABI.getImageRelativeConstant(
3075 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3076 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3077 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3078 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3079 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3080 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3081 ABI.getImageRelativeConstant(
3082 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3084 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3088 llvm::GlobalVariable *
3089 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3090 SmallString<256> MangledName;
3092 llvm::raw_svector_ostream Out(MangledName);
3093 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3096 // Check to see if we've already computed this complete object locator.
3097 if (auto COL = Module.getNamedGlobal(MangledName))
3100 // Compute the fields of the complete object locator.
3101 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3102 int VFPtrOffset = 0;
3103 // The offset includes the vtordisp if one exists.
3104 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3105 if (Context.getASTRecordLayout(RD)
3106 .getVBaseOffsetsMap()
3108 ->second.hasVtorDisp())
3109 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3111 // Forward-declare the complete object locator.
3112 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3113 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3114 /*Initializer=*/nullptr, StringRef(MangledName));
3116 // Initialize the CompleteObjectLocator.
3117 llvm::Constant *Fields[] = {
3118 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3119 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3120 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3121 ABI.getImageRelativeConstant(
3122 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3123 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3124 ABI.getImageRelativeConstant(COL),
3126 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3127 if (!ABI.isImageRelative())
3128 FieldsRef = FieldsRef.drop_back();
3129 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3130 if (COL->isWeakForLinker())
3131 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3135 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3136 /// llvm::GlobalVariable * because different type descriptors have different
3137 /// types, and need to be abstracted. They are abstracting by casting the
3138 /// address to an Int8PtrTy.
3139 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3140 SmallString<256> MangledName, TypeInfoString;
3142 llvm::raw_svector_ostream Out(MangledName);
3143 getMangleContext().mangleCXXRTTI(Type, Out);
3146 // Check to see if we've already declared this TypeDescriptor.
3147 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3148 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3150 // Compute the fields for the TypeDescriptor.
3152 llvm::raw_svector_ostream Out(TypeInfoString);
3153 getMangleContext().mangleCXXRTTIName(Type, Out);
3156 // Declare and initialize the TypeDescriptor.
3157 llvm::Constant *Fields[] = {
3158 getTypeInfoVTable(CGM), // VFPtr
3159 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3160 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3161 llvm::StructType *TypeDescriptorType =
3162 getTypeDescriptorType(TypeInfoString);
3163 auto *Var = new llvm::GlobalVariable(
3164 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3165 getLinkageForRTTI(Type),
3166 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3167 StringRef(MangledName));
3168 if (Var->isWeakForLinker())
3169 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3170 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3173 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3174 llvm::GlobalVariable *
3175 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3176 const VPtrInfo *Info) {
3177 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3180 static void emitCXXConstructor(CodeGenModule &CGM,
3181 const CXXConstructorDecl *ctor,
3182 StructorType ctorType) {
3183 // There are no constructor variants, always emit the complete destructor.
3184 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3185 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3188 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3189 StructorType dtorType) {
3190 // The complete destructor is equivalent to the base destructor for
3191 // classes with no virtual bases, so try to emit it as an alias.
3192 if (!dtor->getParent()->getNumVBases() &&
3193 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3194 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3195 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3196 if (ProducedAlias) {
3197 if (dtorType == StructorType::Complete)
3199 if (dtor->isVirtual())
3200 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3204 // The base destructor is equivalent to the base destructor of its
3205 // base class if there is exactly one non-virtual base class with a
3206 // non-trivial destructor, there are no fields with a non-trivial
3207 // destructor, and the body of the destructor is trivial.
3208 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3211 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3212 if (Fn->isWeakForLinker())
3213 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3216 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3217 StructorType Type) {
3218 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3219 emitCXXConstructor(CGM, CD, Type);
3222 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3226 MicrosoftCXXABI::getAddrOfCXXCopyCtorClosure(const CXXConstructorDecl *CD) {
3227 // Calculate the mangled name.
3228 SmallString<256> ThunkName;
3229 llvm::raw_svector_ostream Out(ThunkName);
3230 getMangleContext().mangleCXXCtor(CD, Ctor_CopyingClosure, Out);
3233 // If the thunk has been generated previously, just return it.
3234 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3235 return cast<llvm::Function>(GV);
3237 // Create the llvm::Function.
3238 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCopyCtorClosure(CD);
3239 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3240 const CXXRecordDecl *RD = CD->getParent();
3241 QualType RecordTy = getContext().getRecordType(RD);
3242 llvm::Function *ThunkFn = llvm::Function::Create(
3243 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3246 CodeGenFunction CGF(CGM);
3247 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3249 // Build FunctionArgs.
3250 FunctionArgList FunctionArgs;
3252 // A copy constructor always starts with a 'this' pointer as its first
3254 buildThisParam(CGF, FunctionArgs);
3256 // Following the 'this' pointer is a reference to the source object that we
3257 // are copying from.
3258 ImplicitParamDecl SrcParam(
3259 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3260 getContext().getLValueReferenceType(RecordTy,
3261 /*SpelledAsLValue=*/true));
3262 FunctionArgs.push_back(&SrcParam);
3264 // Copy constructors for classes which utilize virtual bases have an
3265 // additional parameter which indicates whether or not it is being delegated
3266 // to by a more derived constructor.
3267 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3268 &getContext().Idents.get("is_most_derived"),
3269 getContext().IntTy);
3270 // Only add the parameter to the list if thie class has virtual bases.
3271 if (RD->getNumVBases() > 0)
3272 FunctionArgs.push_back(&IsMostDerived);
3274 // Start defining the function.
3275 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3276 FunctionArgs, CD->getLocation(), SourceLocation());
3278 llvm::Value *This = getThisValue(CGF);
3280 llvm::Value *SrcVal =
3281 CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src");
3285 // Push the this ptr.
3286 Args.add(RValue::get(This), CD->getThisType(getContext()));
3288 // Push the src ptr.
3289 Args.add(RValue::get(SrcVal), SrcParam.getType());
3291 // Add the rest of the default arguments.
3292 std::vector<Stmt *> ArgVec;
3293 for (unsigned I = 1, E = CD->getNumParams(); I != E; ++I)
3294 ArgVec.push_back(getContext().getDefaultArgExprForConstructor(CD, I));
3296 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3298 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3299 ConstExprIterator ArgBegin(ArgVec.data()),
3300 ArgEnd(ArgVec.data() + ArgVec.size());
3301 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, 1);
3303 // Insert any ABI-specific implicit constructor arguments.
3304 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3305 /*ForVirtualBase=*/false,
3306 /*Delegating=*/false, Args);
3308 // Call the destructor with our arguments.
3309 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3310 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3311 Args, CD, Ctor_Complete, ExtraArgs);
3312 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3314 Cleanups.ForceCleanup();
3316 // Emit the ret instruction, remove any temporary instructions created for the
3318 CGF.FinishFunction(SourceLocation());
3323 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3325 int32_t VBPtrOffset,
3327 assert(!T->isReferenceType());
3329 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3330 const CXXConstructorDecl *CD =
3331 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3332 CXXCtorType CT = Ctor_Complete;
3334 CallingConv ExpectedCallingConv = getContext().getDefaultCallingConvention(
3335 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
3336 CallingConv ActualCallingConv =
3337 CD->getType()->getAs<FunctionProtoType>()->getCallConv();
3338 if (ExpectedCallingConv != ActualCallingConv || CD->getNumParams() != 1)
3339 CT = Ctor_CopyingClosure;
3342 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3343 SmallString<256> MangledName;
3345 llvm::raw_svector_ostream Out(MangledName);
3346 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3347 VBPtrOffset, VBIndex, Out);
3349 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3350 return getImageRelativeConstant(GV);
3352 // The TypeDescriptor is used by the runtime to determine if a catch handler
3353 // is appropriate for the exception object.
3354 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3356 // The runtime is responsible for calling the copy constructor if the
3357 // exception is caught by value.
3358 llvm::Constant *CopyCtor;
3360 if (CT == Ctor_CopyingClosure)
3361 CopyCtor = getAddrOfCXXCopyCtorClosure(CD);
3363 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3365 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3367 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3369 CopyCtor = getImageRelativeConstant(CopyCtor);
3371 bool IsScalar = !RD;
3372 bool HasVirtualBases = false;
3373 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3374 QualType PointeeType = T;
3375 if (T->isPointerType())
3376 PointeeType = T->getPointeeType();
3377 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3378 HasVirtualBases = RD->getNumVBases() > 0;
3379 if (IdentifierInfo *II = RD->getIdentifier())
3380 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3383 // Encode the relevant CatchableType properties into the Flags bitfield.
3384 // FIXME: Figure out how bits 2 or 8 can get set.
3388 if (HasVirtualBases)
3393 llvm::Constant *Fields[] = {
3394 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3395 TD, // TypeDescriptor
3396 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3397 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3398 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3399 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3400 CopyCtor // CopyCtor
3402 llvm::StructType *CTType = getCatchableTypeType();
3403 auto *GV = new llvm::GlobalVariable(
3404 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3405 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3406 GV->setUnnamedAddr(true);
3407 GV->setSection(".xdata");
3408 if (GV->isWeakForLinker())
3409 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3410 return getImageRelativeConstant(GV);
3413 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3414 assert(!T->isReferenceType());
3416 // See if we've already generated a CatchableTypeArray for this type before.
3417 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3421 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3422 // using a SmallSetVector. Duplicates may arise due to virtual bases
3423 // occurring more than once in the hierarchy.
3424 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3426 // C++14 [except.handle]p3:
3427 // A handler is a match for an exception object of type E if [...]
3428 // - the handler is of type cv T or cv T& and T is an unambiguous public
3429 // base class of E, or
3430 // - the handler is of type cv T or const T& where T is a pointer type and
3431 // E is a pointer type that can be converted to T by [...]
3432 // - a standard pointer conversion (4.10) not involving conversions to
3433 // pointers to private or protected or ambiguous classes
3434 const CXXRecordDecl *MostDerivedClass = nullptr;
3435 bool IsPointer = T->isPointerType();
3437 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3439 MostDerivedClass = T->getAsCXXRecordDecl();
3441 // Collect all the unambiguous public bases of the MostDerivedClass.
3442 if (MostDerivedClass) {
3443 const ASTContext &Context = CGM.getContext();
3444 const ASTRecordLayout &MostDerivedLayout =
3445 Context.getASTRecordLayout(MostDerivedClass);
3446 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3447 SmallVector<MSRTTIClass, 8> Classes;
3448 serializeClassHierarchy(Classes, MostDerivedClass);
3449 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3450 detectAmbiguousBases(Classes);
3451 for (const MSRTTIClass &Class : Classes) {
3452 // Skip any ambiguous or private bases.
3454 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3456 // Write down how to convert from a derived pointer to a base pointer.
3457 uint32_t OffsetInVBTable = 0;
3458 int32_t VBPtrOffset = -1;
3459 if (Class.VirtualRoot) {
3461 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3462 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3465 // Turn our record back into a pointer if the exception object is a
3467 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3469 RTTITy = Context.getPointerType(RTTITy);
3470 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3471 VBPtrOffset, OffsetInVBTable));
3475 // C++14 [except.handle]p3:
3476 // A handler is a match for an exception object of type E if
3477 // - The handler is of type cv T or cv T& and E and T are the same type
3478 // (ignoring the top-level cv-qualifiers)
3479 CatchableTypes.insert(getCatchableType(T));
3481 // C++14 [except.handle]p3:
3482 // A handler is a match for an exception object of type E if
3483 // - the handler is of type cv T or const T& where T is a pointer type and
3484 // E is a pointer type that can be converted to T by [...]
3485 // - a standard pointer conversion (4.10) not involving conversions to
3486 // pointers to private or protected or ambiguous classes
3488 // All pointers are convertible to pointer-to-void so ensure that it is in the
3489 // CatchableTypeArray.
3491 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3493 // C++14 [except.handle]p3:
3494 // A handler is a match for an exception object of type E if [...]
3495 // - the handler is of type cv T or const T& where T is a pointer or
3496 // pointer to member type and E is std::nullptr_t.
3498 // We cannot possibly list all possible pointer types here, making this
3499 // implementation incompatible with the standard. However, MSVC includes an
3500 // entry for pointer-to-void in this case. Let's do the same.
3501 if (T->isNullPtrType())
3502 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3504 uint32_t NumEntries = CatchableTypes.size();
3505 llvm::Type *CTType =
3506 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3507 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3508 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3509 llvm::Constant *Fields[] = {
3510 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3511 llvm::ConstantArray::get(
3512 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3513 CatchableTypes.end())) // CatchableTypes
3515 SmallString<256> MangledName;
3517 llvm::raw_svector_ostream Out(MangledName);
3518 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3520 CTA = new llvm::GlobalVariable(
3521 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3522 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3523 CTA->setUnnamedAddr(true);
3524 CTA->setSection(".xdata");
3525 if (CTA->isWeakForLinker())
3526 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3530 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3531 T = getContext().getExceptionObjectType(T);
3533 // C++14 [except.handle]p3:
3534 // A handler is a match for an exception object of type E if [...]
3535 // - the handler is of type cv T or const T& where T is a pointer type and
3536 // E is a pointer type that can be converted to T by [...]
3537 // - a qualification conversion
3538 bool IsConst = false, IsVolatile = false;
3539 QualType PointeeType = T->getPointeeType();
3540 if (!PointeeType.isNull()) {
3541 IsConst = PointeeType.isConstQualified();
3542 IsVolatile = PointeeType.isVolatileQualified();
3545 // Member pointer types like "const int A::*" are represented by having RTTI
3546 // for "int A::*" and separately storing the const qualifier.
3547 if (const auto *MPTy = T->getAs<MemberPointerType>())
3548 T = getContext().getMemberPointerType(PointeeType.getUnqualifiedType(),
3551 // Pointer types like "const int * const *" are represented by having RTTI
3552 // for "const int **" and separately storing the const qualifier.
3553 if (T->isPointerType())
3554 T = getContext().getPointerType(PointeeType.getUnqualifiedType());
3556 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3557 // the exception object may be caught as.
3558 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3559 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3560 // This is used as a component of the mangled name which means that we need to
3561 // know what it is in order to see if we have previously generated the
3563 uint32_t NumEntries =
3564 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3565 ->getLimitedValue();
3567 SmallString<256> MangledName;
3569 llvm::raw_svector_ostream Out(MangledName);
3570 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3574 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3576 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3579 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3580 // be at least as CV qualified. Encode this requirement into the Flags
3588 // The cleanup-function (a destructor) must be called when the exception
3589 // object's lifetime ends.
3590 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3591 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3592 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3593 if (!DtorD->isTrivial())
3594 CleanupFn = llvm::ConstantExpr::getBitCast(
3595 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3597 // This is unused as far as we can tell, initialize it to null.
3598 llvm::Constant *ForwardCompat =
3599 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3600 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3601 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3602 llvm::StructType *TIType = getThrowInfoType();
3603 llvm::Constant *Fields[] = {
3604 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3605 getImageRelativeConstant(CleanupFn), // CleanupFn
3606 ForwardCompat, // ForwardCompat
3607 PointerToCatchableTypes // CatchableTypeArray
3609 auto *GV = new llvm::GlobalVariable(
3610 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3611 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3612 GV->setUnnamedAddr(true);
3613 GV->setSection(".xdata");
3614 if (GV->isWeakForLinker())
3615 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3619 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3620 const Expr *SubExpr = E->getSubExpr();
3621 QualType ThrowType = SubExpr->getType();
3622 // The exception object lives on the stack and it's address is passed to the
3623 // runtime function.
3624 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
3625 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
3628 // The so-called ThrowInfo is used to describe how the exception object may be
3630 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
3632 // Call into the runtime to throw the exception.
3633 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
3634 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);