1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr), CatchHandlerTypeType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
88 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override;
90 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
91 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
92 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
94 llvm::Type *StdTypeInfoPtrTy) override;
96 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
97 QualType SrcRecordTy) override;
99 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
100 QualType SrcRecordTy, QualType DestTy,
101 QualType DestRecordTy,
102 llvm::BasicBlock *CastEnd) override;
104 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
105 QualType SrcRecordTy,
106 QualType DestTy) override;
108 bool EmitBadCastCall(CodeGenFunction &CGF) override;
111 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
112 const CXXRecordDecl *ClassDecl,
113 const CXXRecordDecl *BaseClassDecl) override;
116 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
117 const CXXRecordDecl *RD) override;
119 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
120 const CXXRecordDecl *RD) override;
122 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
124 // Background on MSVC destructors
125 // ==============================
127 // Both Itanium and MSVC ABIs have destructor variants. The variant names
128 // roughly correspond in the following way:
130 // Base -> no name, just ~Class
131 // Complete -> vbase destructor
132 // Deleting -> scalar deleting destructor
133 // vector deleting destructor
135 // The base and complete destructors are the same as in Itanium, although the
136 // complete destructor does not accept a VTT parameter when there are virtual
137 // bases. A separate mechanism involving vtordisps is used to ensure that
138 // virtual methods of destroyed subobjects are not called.
140 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
141 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
142 // pointer points to an array. The scalar deleting destructor assumes that
143 // bit 2 is zero, and therefore does not contain a loop.
145 // For virtual destructors, only one entry is reserved in the vftable, and it
146 // always points to the vector deleting destructor. The vector deleting
147 // destructor is the most general, so it can be used to destroy objects in
148 // place, delete single heap objects, or delete arrays.
150 // A TU defining a non-inline destructor is only guaranteed to emit a base
151 // destructor, and all of the other variants are emitted on an as-needed basis
152 // in COMDATs. Because a non-base destructor can be emitted in a TU that
153 // lacks a definition for the destructor, non-base destructors must always
154 // delegate to or alias the base destructor.
156 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
157 SmallVectorImpl<CanQualType> &ArgTys) override;
159 /// Non-base dtors should be emitted as delegating thunks in this ABI.
160 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
161 CXXDtorType DT) const override {
162 return DT != Dtor_Base;
165 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
167 const CXXRecordDecl *
168 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
169 MD = MD->getCanonicalDecl();
170 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
171 MicrosoftVTableContext::MethodVFTableLocation ML =
172 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
173 // The vbases might be ordered differently in the final overrider object
174 // and the complete object, so the "this" argument may sometimes point to
175 // memory that has no particular type (e.g. past the complete object).
176 // In this case, we just use a generic pointer type.
177 // FIXME: might want to have a more precise type in the non-virtual
178 // multiple inheritance case.
179 if (ML.VBase || !ML.VFPtrOffset.isZero())
182 return MD->getParent();
186 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
188 bool VirtualCall) override;
190 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
191 FunctionArgList &Params) override;
193 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
194 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
196 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
198 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
199 const CXXConstructorDecl *D,
200 CXXCtorType Type, bool ForVirtualBase,
202 CallArgList &Args) override;
204 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
205 CXXDtorType Type, bool ForVirtualBase,
206 bool Delegating, llvm::Value *This) override;
208 void emitVTableBitSetEntries(VPtrInfo *Info, const CXXRecordDecl *RD,
209 llvm::GlobalVariable *VTable);
211 void emitVTableDefinitions(CodeGenVTables &CGVT,
212 const CXXRecordDecl *RD) override;
214 llvm::Value *getVTableAddressPointInStructor(
215 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
216 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
217 bool &NeedsVirtualOffset) override;
220 getVTableAddressPointForConstExpr(BaseSubobject Base,
221 const CXXRecordDecl *VTableClass) override;
223 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
224 CharUnits VPtrOffset) override;
226 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
227 llvm::Value *This, llvm::Type *Ty,
228 SourceLocation Loc) override;
230 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
231 const CXXDestructorDecl *Dtor,
232 CXXDtorType DtorType,
234 const CXXMemberCallExpr *CE) override;
236 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
237 CallArgList &CallArgs) override {
238 assert(GD.getDtorType() == Dtor_Deleting &&
239 "Only deleting destructor thunks are available in this ABI");
240 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
244 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
246 llvm::GlobalVariable *
247 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
248 llvm::GlobalVariable::LinkageTypes Linkage);
250 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
251 llvm::GlobalVariable *GV) const;
253 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
254 GlobalDecl GD, bool ReturnAdjustment) override {
255 // Never dllimport/dllexport thunks.
256 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
259 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
261 if (Linkage == GVA_Internal)
262 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
263 else if (ReturnAdjustment)
264 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
266 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
269 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
270 const ThisAdjustment &TA) override;
272 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
273 const ReturnAdjustment &RA) override;
275 void EmitThreadLocalInitFuncs(
277 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
279 ArrayRef<llvm::Function *> CXXThreadLocalInits,
280 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
282 bool usesThreadWrapperFunction() const override { return false; }
283 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
284 QualType LValType) override;
286 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
287 llvm::GlobalVariable *DeclPtr,
288 bool PerformInit) override;
289 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
290 llvm::Constant *Dtor, llvm::Constant *Addr) override;
292 // ==== Notes on array cookies =========
294 // MSVC seems to only use cookies when the class has a destructor; a
295 // two-argument usual array deallocation function isn't sufficient.
297 // For example, this code prints "100" and "1":
300 // void *operator new[](size_t sz) {
301 // printf("%u\n", sz);
302 // return malloc(sz);
304 // void operator delete[](void *p, size_t sz) {
305 // printf("%u\n", sz);
310 // A *p = new A[100];
313 // Whereas it prints "104" and "104" if you give A a destructor.
315 bool requiresArrayCookie(const CXXDeleteExpr *expr,
316 QualType elementType) override;
317 bool requiresArrayCookie(const CXXNewExpr *expr) override;
318 CharUnits getArrayCookieSizeImpl(QualType type) override;
319 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
321 llvm::Value *NumElements,
322 const CXXNewExpr *expr,
323 QualType ElementType) override;
324 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
325 llvm::Value *allocPtr,
326 CharUnits cookieSize) override;
328 friend struct MSRTTIBuilder;
330 bool isImageRelative() const {
331 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
334 // 5 routines for constructing the llvm types for MS RTTI structs.
335 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
336 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
337 TDTypeName += llvm::utostr(TypeInfoString.size());
338 llvm::StructType *&TypeDescriptorType =
339 TypeDescriptorTypeMap[TypeInfoString.size()];
340 if (TypeDescriptorType)
341 return TypeDescriptorType;
342 llvm::Type *FieldTypes[] = {
345 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
347 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
348 return TypeDescriptorType;
351 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
352 if (!isImageRelative())
357 llvm::StructType *getBaseClassDescriptorType() {
358 if (BaseClassDescriptorType)
359 return BaseClassDescriptorType;
360 llvm::Type *FieldTypes[] = {
361 getImageRelativeType(CGM.Int8PtrTy),
367 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
369 BaseClassDescriptorType = llvm::StructType::create(
370 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
371 return BaseClassDescriptorType;
374 llvm::StructType *getClassHierarchyDescriptorType() {
375 if (ClassHierarchyDescriptorType)
376 return ClassHierarchyDescriptorType;
377 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
378 ClassHierarchyDescriptorType = llvm::StructType::create(
379 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
380 llvm::Type *FieldTypes[] = {
384 getImageRelativeType(
385 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
387 ClassHierarchyDescriptorType->setBody(FieldTypes);
388 return ClassHierarchyDescriptorType;
391 llvm::StructType *getCompleteObjectLocatorType() {
392 if (CompleteObjectLocatorType)
393 return CompleteObjectLocatorType;
394 CompleteObjectLocatorType = llvm::StructType::create(
395 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
396 llvm::Type *FieldTypes[] = {
400 getImageRelativeType(CGM.Int8PtrTy),
401 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
402 getImageRelativeType(CompleteObjectLocatorType),
404 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
405 if (!isImageRelative())
406 FieldTypesRef = FieldTypesRef.drop_back();
407 CompleteObjectLocatorType->setBody(FieldTypesRef);
408 return CompleteObjectLocatorType;
411 llvm::GlobalVariable *getImageBase() {
412 StringRef Name = "__ImageBase";
413 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
416 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
418 llvm::GlobalValue::ExternalLinkage,
419 /*Initializer=*/nullptr, Name);
422 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
423 if (!isImageRelative())
426 if (PtrVal->isNullValue())
427 return llvm::Constant::getNullValue(CGM.IntTy);
429 llvm::Constant *ImageBaseAsInt =
430 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
431 llvm::Constant *PtrValAsInt =
432 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
433 llvm::Constant *Diff =
434 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
435 /*HasNUW=*/true, /*HasNSW=*/true);
436 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
440 MicrosoftMangleContext &getMangleContext() {
441 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
444 llvm::Constant *getZeroInt() {
445 return llvm::ConstantInt::get(CGM.IntTy, 0);
448 llvm::Constant *getAllOnesInt() {
449 return llvm::Constant::getAllOnesValue(CGM.IntTy);
452 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
453 return C ? C : getZeroInt();
456 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
457 return C ? C : getZeroInt();
460 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
463 GetNullMemberPointerFields(const MemberPointerType *MPT,
464 llvm::SmallVectorImpl<llvm::Constant *> &fields);
466 /// \brief Shared code for virtual base adjustment. Returns the offset from
467 /// the vbptr to the virtual base. Optionally returns the address of the
469 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
471 llvm::Value *VBPtrOffset,
472 llvm::Value *VBTableOffset,
473 llvm::Value **VBPtr = nullptr);
475 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
478 int32_t VBTableOffset,
479 llvm::Value **VBPtr = nullptr) {
480 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
481 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
482 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
483 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
486 std::pair<llvm::Value *, llvm::Value *>
487 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
488 QualType SrcRecordTy);
490 /// \brief Performs a full virtual base adjustment. Used to dereference
491 /// pointers to members of virtual bases.
492 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
493 const CXXRecordDecl *RD, llvm::Value *Base,
494 llvm::Value *VirtualBaseAdjustmentOffset,
495 llvm::Value *VBPtrOffset /* optional */);
497 /// \brief Emits a full member pointer with the fields common to data and
498 /// function member pointers.
499 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
500 bool IsMemberFunction,
501 const CXXRecordDecl *RD,
502 CharUnits NonVirtualBaseAdjustment,
503 unsigned VBTableIndex);
505 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
508 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
509 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
511 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
512 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
514 /// \brief Generate a thunk for calling a virtual member function MD.
515 llvm::Function *EmitVirtualMemPtrThunk(
516 const CXXMethodDecl *MD,
517 const MicrosoftVTableContext::MethodVFTableLocation &ML);
520 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
522 bool isZeroInitializable(const MemberPointerType *MPT) override;
524 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
525 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
526 return RD->hasAttr<MSInheritanceAttr>();
529 bool isTypeInfoCalculable(QualType Ty) const override {
530 if (!CGCXXABI::isTypeInfoCalculable(Ty))
532 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
533 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
534 if (!RD->hasAttr<MSInheritanceAttr>())
540 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
542 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
543 CharUnits offset) override;
544 llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override;
545 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
547 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
550 const MemberPointerType *MPT,
551 bool Inequality) override;
553 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
555 const MemberPointerType *MPT) override;
558 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
559 llvm::Value *Base, llvm::Value *MemPtr,
560 const MemberPointerType *MPT) override;
562 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
564 llvm::Value *Src) override;
566 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
567 llvm::Constant *Src) override;
569 llvm::Constant *EmitMemberPointerConversion(
570 const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
571 CastKind CK, CastExpr::path_const_iterator PathBegin,
572 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
575 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
576 llvm::Value *&This, llvm::Value *MemPtr,
577 const MemberPointerType *MPT) override;
579 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
581 llvm::StructType *getCatchHandlerTypeType() {
582 if (!CatchHandlerTypeType) {
583 llvm::Type *FieldTypes[] = {
585 CGM.Int8PtrTy, // TypeDescriptor
587 CatchHandlerTypeType = llvm::StructType::create(
588 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
590 return CatchHandlerTypeType;
593 llvm::StructType *getCatchableTypeType() {
594 if (CatchableTypeType)
595 return CatchableTypeType;
596 llvm::Type *FieldTypes[] = {
598 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
599 CGM.IntTy, // NonVirtualAdjustment
600 CGM.IntTy, // OffsetToVBPtr
601 CGM.IntTy, // VBTableIndex
603 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
605 CatchableTypeType = llvm::StructType::create(
606 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
607 return CatchableTypeType;
610 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
611 llvm::StructType *&CatchableTypeArrayType =
612 CatchableTypeArrayTypeMap[NumEntries];
613 if (CatchableTypeArrayType)
614 return CatchableTypeArrayType;
616 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
617 CTATypeName += llvm::utostr(NumEntries);
619 getImageRelativeType(getCatchableTypeType()->getPointerTo());
620 llvm::Type *FieldTypes[] = {
621 CGM.IntTy, // NumEntries
622 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
624 CatchableTypeArrayType =
625 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
626 return CatchableTypeArrayType;
629 llvm::StructType *getThrowInfoType() {
631 return ThrowInfoType;
632 llvm::Type *FieldTypes[] = {
634 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
635 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
636 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
638 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
640 return ThrowInfoType;
643 llvm::Constant *getThrowFn() {
644 // _CxxThrowException is passed an exception object and a ThrowInfo object
645 // which describes the exception.
646 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
647 llvm::FunctionType *FTy =
648 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
649 auto *Fn = cast<llvm::Function>(
650 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
651 // _CxxThrowException is stdcall on 32-bit x86 platforms.
652 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
653 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
657 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
660 llvm::Constant *getCatchableType(QualType T,
661 uint32_t NVOffset = 0,
662 int32_t VBPtrOffset = -1,
663 uint32_t VBIndex = 0);
665 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
667 llvm::GlobalVariable *getThrowInfo(QualType T) override;
670 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
671 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
672 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
673 /// \brief All the vftables that have been referenced.
674 VFTablesMapTy VFTablesMap;
675 VTablesMapTy VTablesMap;
677 /// \brief This set holds the record decls we've deferred vtable emission for.
678 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
681 /// \brief All the vbtables which have been referenced.
682 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
684 /// Info on the global variable used to guard initialization of static locals.
685 /// The BitIndex field is only used for externally invisible declarations.
687 GuardInfo() : Guard(nullptr), BitIndex(0) {}
688 llvm::GlobalVariable *Guard;
692 /// Map from DeclContext to the current guard variable. We assume that the
693 /// AST is visited in source code order.
694 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
695 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
696 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
698 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
699 llvm::StructType *BaseClassDescriptorType;
700 llvm::StructType *ClassHierarchyDescriptorType;
701 llvm::StructType *CompleteObjectLocatorType;
703 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
705 llvm::StructType *CatchableTypeType;
706 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
707 llvm::StructType *ThrowInfoType;
708 llvm::StructType *CatchHandlerTypeType;
713 CGCXXABI::RecordArgABI
714 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
715 switch (CGM.getTarget().getTriple().getArch()) {
717 // FIXME: Implement for other architectures.
720 case llvm::Triple::x86:
721 // All record arguments are passed in memory on x86. Decide whether to
722 // construct the object directly in argument memory, or to construct the
723 // argument elsewhere and copy the bytes during the call.
725 // If C++ prohibits us from making a copy, construct the arguments directly
726 // into argument memory.
727 if (!canCopyArgument(RD))
728 return RAA_DirectInMemory;
730 // Otherwise, construct the argument into a temporary and copy the bytes
731 // into the outgoing argument memory.
734 case llvm::Triple::x86_64:
735 // Win64 passes objects with non-trivial copy ctors indirectly.
736 if (RD->hasNonTrivialCopyConstructor())
739 // If an object has a destructor, we'd really like to pass it indirectly
740 // because it allows us to elide copies. Unfortunately, MSVC makes that
741 // impossible for small types, which it will pass in a single register or
742 // stack slot. Most objects with dtors are large-ish, so handle that early.
743 // We can't call out all large objects as being indirect because there are
744 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
745 // how we pass large POD types.
746 if (RD->hasNonTrivialDestructor() &&
747 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
750 // We have a trivial copy constructor or no copy constructors, but we have
751 // to make sure it isn't deleted.
752 bool CopyDeleted = false;
753 for (const CXXConstructorDecl *CD : RD->ctors()) {
754 if (CD->isCopyConstructor()) {
755 assert(CD->isTrivial());
756 // We had at least one undeleted trivial copy ctor. Return directly.
757 if (!CD->isDeleted())
763 // The trivial copy constructor was deleted. Return indirectly.
767 // There were no copy ctors. Return in RAX.
771 llvm_unreachable("invalid enum");
774 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
775 const CXXDeleteExpr *DE,
777 QualType ElementType,
778 const CXXDestructorDecl *Dtor) {
779 // FIXME: Provide a source location here even though there's no
780 // CXXMemberCallExpr for dtor call.
781 bool UseGlobalDelete = DE->isGlobalDelete();
782 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
783 llvm::Value *MDThis =
784 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
786 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
789 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
790 llvm::Value *Args[] = {
791 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
792 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
793 auto *Fn = getThrowFn();
795 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
797 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
801 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
802 CallEndCatchMSVC() {}
803 void Emit(CodeGenFunction &CGF, Flags flags) override {
804 CGF.EmitNounwindRuntimeCall(
805 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
810 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
811 const CXXCatchStmt *S) {
812 // In the MS ABI, the runtime handles the copy, and the catch handler is
813 // responsible for destruction.
814 VarDecl *CatchParam = S->getExceptionDecl();
815 llvm::Value *Exn = CGF.getExceptionFromSlot();
816 llvm::Function *BeginCatch =
817 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
819 // If this is a catch-all or the catch parameter is unnamed, we don't need to
820 // emit an alloca to the object.
821 if (!CatchParam || !CatchParam->getDeclName()) {
822 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
823 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
824 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
828 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
829 llvm::Value *ParamAddr =
830 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
831 llvm::Value *Args[2] = {Exn, ParamAddr};
832 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
833 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
834 CGF.EmitAutoVarCleanups(var);
837 std::pair<llvm::Value *, llvm::Value *>
838 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
839 QualType SrcRecordTy) {
840 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
841 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
842 const ASTContext &Context = getContext();
844 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
845 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
847 // Perform a base adjustment.
848 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
849 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
850 [&](const CXXBaseSpecifier &Base) {
851 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
852 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
854 llvm::Value *Offset = GetVirtualBaseClassOffset(
855 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
856 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
857 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
858 return std::make_pair(Value, Offset);
861 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
862 QualType SrcRecordTy) {
863 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
865 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
868 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
869 llvm::Value *Argument) {
870 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
871 llvm::FunctionType *FTy =
872 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
873 llvm::Value *Args[] = {Argument};
874 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
875 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
878 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
879 llvm::CallSite Call =
880 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
881 Call.setDoesNotReturn();
882 CGF.Builder.CreateUnreachable();
885 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
886 QualType SrcRecordTy,
887 llvm::Value *ThisPtr,
888 llvm::Type *StdTypeInfoPtrTy) {
890 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
891 return CGF.Builder.CreateBitCast(
892 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
895 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
896 QualType SrcRecordTy) {
897 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
899 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
902 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
903 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
904 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
905 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
907 llvm::Value *SrcRTTI =
908 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
909 llvm::Value *DestRTTI =
910 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
913 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
915 // PVOID __RTDynamicCast(
921 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
922 CGF.Int8PtrTy, CGF.Int32Ty};
923 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
924 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
926 llvm::Value *Args[] = {
927 Value, Offset, SrcRTTI, DestRTTI,
928 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
929 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
930 return CGF.Builder.CreateBitCast(Value, DestLTy);
934 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
935 QualType SrcRecordTy,
938 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
940 // PVOID __RTCastToVoid(
942 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
943 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
944 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
946 llvm::Value *Args[] = {Value};
947 return CGF.EmitRuntimeCall(Function, Args);
950 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
954 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
955 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
956 const CXXRecordDecl *BaseClassDecl) {
957 const ASTContext &Context = getContext();
959 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
960 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
961 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
962 CharUnits VBTableChars =
964 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
965 llvm::Value *VBTableOffset =
966 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
968 llvm::Value *VBPtrToNewBase =
969 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
971 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
972 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
975 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
976 return isa<CXXConstructorDecl>(GD.getDecl());
979 static bool isDeletingDtor(GlobalDecl GD) {
980 return isa<CXXDestructorDecl>(GD.getDecl()) &&
981 GD.getDtorType() == Dtor_Deleting;
984 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
985 return isDeletingDtor(GD);
988 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
989 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
993 if (FI.isInstanceMethod()) {
994 // If it's an instance method, aggregates are always returned indirectly via
995 // the second parameter.
996 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
997 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
999 } else if (!RD->isPOD()) {
1000 // If it's a free function, non-POD types are returned indirectly.
1001 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1005 // Otherwise, use the C ABI rules.
1010 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1011 const CXXRecordDecl *RD) {
1012 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1013 assert(IsMostDerivedClass &&
1014 "ctor for a class with virtual bases must have an implicit parameter");
1015 llvm::Value *IsCompleteObject =
1016 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1018 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1019 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1020 CGF.Builder.CreateCondBr(IsCompleteObject,
1021 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1023 CGF.EmitBlock(CallVbaseCtorsBB);
1025 // Fill in the vbtable pointers here.
1026 EmitVBPtrStores(CGF, RD);
1028 // CGF will put the base ctor calls in this basic block for us later.
1030 return SkipVbaseCtorsBB;
1033 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1034 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1035 // In most cases, an override for a vbase virtual method can adjust
1036 // the "this" parameter by applying a constant offset.
1037 // However, this is not enough while a constructor or a destructor of some
1038 // class X is being executed if all the following conditions are met:
1039 // - X has virtual bases, (1)
1040 // - X overrides a virtual method M of a vbase Y, (2)
1041 // - X itself is a vbase of the most derived class.
1043 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1044 // which holds the extra amount of "this" adjustment we must do when we use
1045 // the X vftables (i.e. during X ctor or dtor).
1046 // Outside the ctors and dtors, the values of vtorDisps are zero.
1048 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1049 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1050 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1051 CGBuilderTy &Builder = CGF.Builder;
1054 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1055 llvm::Value *Int8This = nullptr; // Initialize lazily.
1057 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1059 if (!I->second.hasVtorDisp())
1062 llvm::Value *VBaseOffset =
1063 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1064 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1065 // just to Trunc back immediately.
1066 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1067 uint64_t ConstantVBaseOffset =
1068 Layout.getVBaseClassOffset(I->first).getQuantity();
1070 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1071 llvm::Value *VtorDispValue = Builder.CreateSub(
1072 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1076 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1077 CGF.Int8Ty->getPointerTo(AS));
1078 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1079 // vtorDisp is always the 32-bits before the vbase in the class layout.
1080 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1081 VtorDispPtr = Builder.CreateBitCast(
1082 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1084 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1088 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1089 const CXXMethodDecl *MD) {
1090 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1091 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1092 CallingConv ActualCallingConv =
1093 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1094 return ExpectedCallingConv == ActualCallingConv;
1097 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1098 // There's only one constructor type in this ABI.
1099 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1101 // Exported default constructors either have a simple call-site where they use
1102 // the typical calling convention and have a single 'this' pointer for an
1103 // argument -or- they get a wrapper function which appropriately thunks to the
1104 // real default constructor. This thunk is the default constructor closure.
1105 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1106 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1107 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1108 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1109 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1113 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1114 const CXXRecordDecl *RD) {
1115 llvm::Value *ThisInt8Ptr =
1116 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1117 const ASTContext &Context = getContext();
1118 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1120 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1121 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1122 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1123 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1124 const ASTRecordLayout &SubobjectLayout =
1125 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1126 CharUnits Offs = VBT->NonVirtualOffset;
1127 Offs += SubobjectLayout.getVBPtrOffset();
1128 if (VBT->getVBaseWithVPtr())
1129 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1130 llvm::Value *VBPtr =
1131 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1132 llvm::Value *GVPtr =
1133 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1134 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1135 "vbptr." + VBT->ReusingBase->getName());
1136 CGF.Builder.CreateStore(GVPtr, VBPtr);
1141 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1142 SmallVectorImpl<CanQualType> &ArgTys) {
1143 // TODO: 'for base' flag
1144 if (T == StructorType::Deleting) {
1145 // The scalar deleting destructor takes an implicit int parameter.
1146 ArgTys.push_back(getContext().IntTy);
1148 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1152 // All parameters are already in place except is_most_derived, which goes
1153 // after 'this' if it's variadic and last if it's not.
1155 const CXXRecordDecl *Class = CD->getParent();
1156 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1157 if (Class->getNumVBases()) {
1158 if (FPT->isVariadic())
1159 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1161 ArgTys.push_back(getContext().IntTy);
1165 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1166 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1167 // other destructor variants are delegating thunks.
1168 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1172 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1173 GD = GD.getCanonicalDecl();
1174 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1176 GlobalDecl LookupGD = GD;
1177 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1178 // Complete destructors take a pointer to the complete object as a
1179 // parameter, thus don't need this adjustment.
1180 if (GD.getDtorType() == Dtor_Complete)
1183 // There's no Dtor_Base in vftable but it shares the this adjustment with
1184 // the deleting one, so look it up instead.
1185 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1188 MicrosoftVTableContext::MethodVFTableLocation ML =
1189 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1190 CharUnits Adjustment = ML.VFPtrOffset;
1192 // Normal virtual instance methods need to adjust from the vfptr that first
1193 // defined the virtual method to the virtual base subobject, but destructors
1194 // do not. The vector deleting destructor thunk applies this adjustment for
1196 if (isa<CXXDestructorDecl>(MD))
1197 Adjustment = CharUnits::Zero();
1200 const ASTRecordLayout &DerivedLayout =
1201 getContext().getASTRecordLayout(MD->getParent());
1202 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1208 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1209 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1211 // If the call of a virtual function is not virtual, we just have to
1212 // compensate for the adjustment the virtual function does in its prologue.
1213 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1214 if (Adjustment.isZero())
1217 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1218 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1219 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1220 assert(Adjustment.isPositive());
1221 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1224 GD = GD.getCanonicalDecl();
1225 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1227 GlobalDecl LookupGD = GD;
1228 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1229 // Complete dtors take a pointer to the complete object,
1230 // thus don't need adjustment.
1231 if (GD.getDtorType() == Dtor_Complete)
1234 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1235 // with the base one, so look up the deleting one instead.
1236 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1238 MicrosoftVTableContext::MethodVFTableLocation ML =
1239 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1241 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1242 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1243 CharUnits StaticOffset = ML.VFPtrOffset;
1245 // Base destructors expect 'this' to point to the beginning of the base
1246 // subobject, not the first vfptr that happens to contain the virtual dtor.
1247 // However, we still need to apply the virtual base adjustment.
1248 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1249 StaticOffset = CharUnits::Zero();
1252 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1253 llvm::Value *VBaseOffset =
1254 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1255 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1257 if (!StaticOffset.isZero()) {
1258 assert(StaticOffset.isPositive());
1259 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1261 // Non-virtual adjustment might result in a pointer outside the allocated
1262 // object, e.g. if the final overrider class is laid out after the virtual
1263 // base that declares a method in the most derived class.
1264 // FIXME: Update the code that emits this adjustment in thunks prologues.
1265 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1267 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1268 StaticOffset.getQuantity());
1274 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1276 FunctionArgList &Params) {
1277 ASTContext &Context = getContext();
1278 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1279 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1280 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1281 ImplicitParamDecl *IsMostDerived
1282 = ImplicitParamDecl::Create(Context, nullptr,
1283 CGF.CurGD.getDecl()->getLocation(),
1284 &Context.Idents.get("is_most_derived"),
1286 // The 'most_derived' parameter goes second if the ctor is variadic and last
1287 // if it's not. Dtors can't be variadic.
1288 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1289 if (FPT->isVariadic())
1290 Params.insert(Params.begin() + 1, IsMostDerived);
1292 Params.push_back(IsMostDerived);
1293 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1294 } else if (isDeletingDtor(CGF.CurGD)) {
1295 ImplicitParamDecl *ShouldDelete
1296 = ImplicitParamDecl::Create(Context, nullptr,
1297 CGF.CurGD.getDecl()->getLocation(),
1298 &Context.Idents.get("should_call_delete"),
1300 Params.push_back(ShouldDelete);
1301 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1305 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1306 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1307 // In this ABI, every virtual function takes a pointer to one of the
1308 // subobjects that first defines it as the 'this' parameter, rather than a
1309 // pointer to the final overrider subobject. Thus, we need to adjust it back
1310 // to the final overrider subobject before use.
1311 // See comments in the MicrosoftVFTableContext implementation for the details.
1312 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1313 if (Adjustment.isZero())
1316 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1317 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1318 *thisTy = This->getType();
1320 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1321 assert(Adjustment.isPositive());
1322 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1323 -Adjustment.getQuantity());
1324 return CGF.Builder.CreateBitCast(This, thisTy);
1327 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1330 /// If this is a function that the ABI specifies returns 'this', initialize
1331 /// the return slot to 'this' at the start of the function.
1333 /// Unlike the setting of return types, this is done within the ABI
1334 /// implementation instead of by clients of CGCXXABI because:
1335 /// 1) getThisValue is currently protected
1336 /// 2) in theory, an ABI could implement 'this' returns some other way;
1337 /// HasThisReturn only specifies a contract, not the implementation
1338 if (HasThisReturn(CGF.CurGD))
1339 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1340 else if (hasMostDerivedReturn(CGF.CurGD))
1341 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1344 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1345 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1346 assert(getStructorImplicitParamDecl(CGF) &&
1347 "no implicit parameter for a constructor with virtual bases?");
1348 getStructorImplicitParamValue(CGF)
1349 = CGF.Builder.CreateLoad(
1350 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1354 if (isDeletingDtor(CGF.CurGD)) {
1355 assert(getStructorImplicitParamDecl(CGF) &&
1356 "no implicit parameter for a deleting destructor?");
1357 getStructorImplicitParamValue(CGF)
1358 = CGF.Builder.CreateLoad(
1359 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1360 "should_call_delete");
1364 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1365 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1366 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1367 assert(Type == Ctor_Complete || Type == Ctor_Base);
1369 // Check if we need a 'most_derived' parameter.
1370 if (!D->getParent()->getNumVBases())
1373 // Add the 'most_derived' argument second if we are variadic or last if not.
1374 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1375 llvm::Value *MostDerivedArg =
1376 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1377 RValue RV = RValue::get(MostDerivedArg);
1378 if (MostDerivedArg) {
1379 if (FPT->isVariadic())
1380 Args.insert(Args.begin() + 1,
1381 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1383 Args.add(RV, getContext().IntTy);
1386 return 1; // Added one arg.
1389 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1390 const CXXDestructorDecl *DD,
1391 CXXDtorType Type, bool ForVirtualBase,
1392 bool Delegating, llvm::Value *This) {
1393 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1395 if (DD->isVirtual()) {
1396 assert(Type != CXXDtorType::Dtor_Deleting &&
1397 "The deleting destructor should only be called via a virtual call");
1398 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1402 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1403 /*ImplicitParam=*/nullptr,
1404 /*ImplicitParamTy=*/QualType(), nullptr,
1405 getFromDtorType(Type));
1408 void MicrosoftCXXABI::emitVTableBitSetEntries(VPtrInfo *Info,
1409 const CXXRecordDecl *RD,
1410 llvm::GlobalVariable *VTable) {
1411 if (!getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIVCall) &&
1412 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFINVCall) &&
1413 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIDerivedCast) &&
1414 !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIUnrelatedCast))
1417 llvm::NamedMDNode *BitsetsMD =
1418 CGM.getModule().getOrInsertNamedMetadata("llvm.bitsets");
1419 CharUnits PointerWidth = getContext().toCharUnitsFromBits(
1420 getContext().getTargetInfo().getPointerWidth(0));
1422 // FIXME: Add blacklisting scheme.
1424 if (Info->PathToBaseWithVPtr.empty()) {
1425 BitsetsMD->addOperand(
1426 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, RD));
1430 // Add a bitset entry for the least derived base belonging to this vftable.
1431 BitsetsMD->addOperand(CGM.CreateVTableBitSetEntry(
1432 VTable, PointerWidth, Info->PathToBaseWithVPtr.back()));
1434 // Add a bitset entry for each derived class that is laid out at the same
1435 // offset as the least derived base.
1436 for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) {
1437 const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1];
1438 const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I];
1440 const ASTRecordLayout &Layout =
1441 getContext().getASTRecordLayout(DerivedRD);
1443 auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD);
1444 if (VBI == Layout.getVBaseOffsetsMap().end())
1445 Offset = Layout.getBaseClassOffset(BaseRD);
1447 Offset = VBI->second.VBaseOffset;
1448 if (!Offset.isZero())
1450 BitsetsMD->addOperand(
1451 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, DerivedRD));
1454 // Finally do the same for the most derived class.
1455 if (Info->FullOffsetInMDC.isZero())
1456 BitsetsMD->addOperand(
1457 CGM.CreateVTableBitSetEntry(VTable, PointerWidth, RD));
1460 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1461 const CXXRecordDecl *RD) {
1462 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1463 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1465 for (VPtrInfo *Info : VFPtrs) {
1466 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1467 if (VTable->hasInitializer())
1470 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1471 ? getMSCompleteObjectLocator(RD, Info)
1474 const VTableLayout &VTLayout =
1475 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1476 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1477 RD, VTLayout.vtable_component_begin(),
1478 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1479 VTLayout.getNumVTableThunks(), RTTI);
1481 VTable->setInitializer(Init);
1483 emitVTableBitSetEntries(Info, RD, VTable);
1487 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1488 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1489 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1490 NeedsVirtualOffset = (NearestVBase != nullptr);
1492 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1493 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1494 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1495 if (!VTableAddressPoint) {
1496 assert(Base.getBase()->getNumVBases() &&
1497 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1499 return VTableAddressPoint;
1502 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1503 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1504 SmallString<256> &Name) {
1505 llvm::raw_svector_ostream Out(Name);
1506 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1509 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1510 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1511 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1512 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1513 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1514 assert(VFTable && "Couldn't find a vftable for the given base?");
1518 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1519 CharUnits VPtrOffset) {
1520 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1521 // shouldn't be used in the given record type. We want to cache this result in
1522 // VFTablesMap, thus a simple zero check is not sufficient.
1523 VFTableIdTy ID(RD, VPtrOffset);
1524 VTablesMapTy::iterator I;
1526 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1530 llvm::GlobalVariable *&VTable = I->second;
1532 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1533 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1535 if (DeferredVFTables.insert(RD).second) {
1536 // We haven't processed this record type before.
1537 // Queue up this v-table for possible deferred emission.
1538 CGM.addDeferredVTable(RD);
1541 // Create all the vftables at once in order to make sure each vftable has
1542 // a unique mangled name.
1543 llvm::StringSet<> ObservedMangledNames;
1544 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1545 SmallString<256> Name;
1546 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1547 if (!ObservedMangledNames.insert(Name.str()).second)
1548 llvm_unreachable("Already saw this mangling before?");
1553 VPtrInfo *const *VFPtrI =
1554 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1555 return VPI->FullOffsetInMDC == VPtrOffset;
1557 if (VFPtrI == VFPtrs.end()) {
1558 VFTablesMap[ID] = nullptr;
1561 VPtrInfo *VFPtr = *VFPtrI;
1563 SmallString<256> VFTableName;
1564 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1566 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1567 bool VFTableComesFromAnotherTU =
1568 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1569 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1570 bool VTableAliasIsRequred =
1571 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1573 if (llvm::GlobalValue *VFTable =
1574 CGM.getModule().getNamedGlobal(VFTableName)) {
1575 VFTablesMap[ID] = VFTable;
1576 return VTableAliasIsRequred
1577 ? cast<llvm::GlobalVariable>(
1578 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1579 : cast<llvm::GlobalVariable>(VFTable);
1582 uint64_t NumVTableSlots =
1583 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1584 .getNumVTableComponents();
1585 llvm::GlobalValue::LinkageTypes VTableLinkage =
1586 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1588 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1590 llvm::ArrayType *VTableType =
1591 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1593 // Create a backing variable for the contents of VTable. The VTable may
1594 // or may not include space for a pointer to RTTI data.
1595 llvm::GlobalValue *VFTable;
1596 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1597 /*isConstant=*/true, VTableLinkage,
1598 /*Initializer=*/nullptr, VTableName);
1599 VTable->setUnnamedAddr(true);
1601 llvm::Comdat *C = nullptr;
1602 if (!VFTableComesFromAnotherTU &&
1603 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1604 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1605 VTableAliasIsRequred)))
1606 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1608 // Only insert a pointer into the VFTable for RTTI data if we are not
1609 // importing it. We never reference the RTTI data directly so there is no
1610 // need to make room for it.
1611 if (VTableAliasIsRequred) {
1612 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1613 llvm::ConstantInt::get(CGM.IntTy, 1)};
1614 // Create a GEP which points just after the first entry in the VFTable,
1615 // this should be the location of the first virtual method.
1616 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1617 VTable->getValueType(), VTable, GEPIndices);
1618 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1619 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1621 C->setSelectionKind(llvm::Comdat::Largest);
1623 VFTable = llvm::GlobalAlias::create(
1624 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1625 VFTableName.str(), VTableGEP, &CGM.getModule());
1626 VFTable->setUnnamedAddr(true);
1628 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1629 // be referencing any RTTI data.
1630 // The GlobalVariable will end up being an appropriate definition of the
1635 VTable->setComdat(C);
1637 if (RD->hasAttr<DLLImportAttr>())
1638 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1639 else if (RD->hasAttr<DLLExportAttr>())
1640 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1642 VFTablesMap[ID] = VFTable;
1646 // Compute the identity of the most derived class whose virtual table is located
1647 // at the given offset into RD.
1648 static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx,
1649 const CXXRecordDecl *RD,
1651 if (Offset.isZero())
1654 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
1655 const CXXRecordDecl *MaxBase = nullptr;
1656 CharUnits MaxBaseOffset;
1657 for (auto &&B : RD->bases()) {
1658 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1659 CharUnits BaseOffset = Layout.getBaseClassOffset(Base);
1660 if (BaseOffset <= Offset && BaseOffset > MaxBaseOffset) {
1662 MaxBaseOffset = BaseOffset;
1665 for (auto &&B : RD->vbases()) {
1666 const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl();
1667 CharUnits BaseOffset = Layout.getVBaseClassOffset(Base);
1668 if (BaseOffset <= Offset && BaseOffset > MaxBaseOffset) {
1670 MaxBaseOffset = BaseOffset;
1674 return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset);
1677 // Compute the identity of the most derived class whose virtual table is located
1678 // at the MethodVFTableLocation ML.
1679 static const CXXRecordDecl *
1680 getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD,
1681 MicrosoftVTableContext::MethodVFTableLocation &ML) {
1682 const CXXRecordDecl *RD = ML.VBase;
1684 RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
1686 return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset);
1689 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1693 SourceLocation Loc) {
1694 GD = GD.getCanonicalDecl();
1695 CGBuilderTy &Builder = CGF.Builder;
1697 Ty = Ty->getPointerTo()->getPointerTo();
1699 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1700 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1702 MicrosoftVTableContext::MethodVFTableLocation ML =
1703 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1704 if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
1705 CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML),
1706 VTable, CodeGenFunction::CFITCK_VCall, Loc);
1708 llvm::Value *VFuncPtr =
1709 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1710 return Builder.CreateLoad(VFuncPtr);
1713 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1714 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1715 llvm::Value *This, const CXXMemberCallExpr *CE) {
1716 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1717 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1719 // We have only one destructor in the vftable but can get both behaviors
1720 // by passing an implicit int parameter.
1721 GlobalDecl GD(Dtor, Dtor_Deleting);
1722 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1723 Dtor, StructorType::Deleting);
1724 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1725 llvm::Value *Callee = getVirtualFunctionPointer(
1726 CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation());
1728 ASTContext &Context = getContext();
1729 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1730 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1731 DtorType == Dtor_Deleting);
1733 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1734 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1735 ImplicitParam, Context.IntTy, CE,
1736 StructorType::Deleting);
1737 return RV.getScalarVal();
1740 const VBTableGlobals &
1741 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1742 // At this layer, we can key the cache off of a single class, which is much
1743 // easier than caching each vbtable individually.
1744 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1746 std::tie(Entry, Added) =
1747 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1748 VBTableGlobals &VBGlobals = Entry->second;
1752 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1753 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1755 // Cache the globals for all vbtables so we don't have to recompute the
1757 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1758 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1759 E = VBGlobals.VBTables->end();
1761 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1767 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1768 const CXXMethodDecl *MD,
1769 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1770 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1771 "can't form pointers to ctors or virtual dtors");
1773 // Calculate the mangled name.
1774 SmallString<256> ThunkName;
1775 llvm::raw_svector_ostream Out(ThunkName);
1776 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1779 // If the thunk has been generated previously, just return it.
1780 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1781 return cast<llvm::Function>(GV);
1783 // Create the llvm::Function.
1784 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1785 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1786 llvm::Function *ThunkFn =
1787 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1788 ThunkName.str(), &CGM.getModule());
1789 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1791 ThunkFn->setLinkage(MD->isExternallyVisible()
1792 ? llvm::GlobalValue::LinkOnceODRLinkage
1793 : llvm::GlobalValue::InternalLinkage);
1794 if (MD->isExternallyVisible())
1795 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1797 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1798 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1800 // Add the "thunk" attribute so that LLVM knows that the return type is
1801 // meaningless. These thunks can be used to call functions with differing
1802 // return types, and the caller is required to cast the prototype
1803 // appropriately to extract the correct value.
1804 ThunkFn->addFnAttr("thunk");
1806 // These thunks can be compared, so they are not unnamed.
1807 ThunkFn->setUnnamedAddr(false);
1810 CodeGenFunction CGF(CGM);
1811 CGF.CurGD = GlobalDecl(MD);
1812 CGF.CurFuncIsThunk = true;
1814 // Build FunctionArgs, but only include the implicit 'this' parameter
1816 FunctionArgList FunctionArgs;
1817 buildThisParam(CGF, FunctionArgs);
1819 // Start defining the function.
1820 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1821 FunctionArgs, MD->getLocation(), SourceLocation());
1824 // Load the vfptr and then callee from the vftable. The callee should have
1825 // adjusted 'this' so that the vfptr is at offset zero.
1826 llvm::Value *VTable = CGF.GetVTablePtr(
1827 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1828 llvm::Value *VFuncPtr =
1829 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1830 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1832 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1837 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1838 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1839 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1840 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1841 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1842 if (GV->isDeclaration())
1843 emitVBTableDefinition(*VBT, RD, GV);
1847 llvm::GlobalVariable *
1848 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1849 llvm::GlobalVariable::LinkageTypes Linkage) {
1850 SmallString<256> OutName;
1851 llvm::raw_svector_ostream Out(OutName);
1852 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1854 StringRef Name = OutName.str();
1856 llvm::ArrayType *VBTableType =
1857 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1859 assert(!CGM.getModule().getNamedGlobal(Name) &&
1860 "vbtable with this name already exists: mangling bug?");
1861 llvm::GlobalVariable *GV =
1862 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1863 GV->setUnnamedAddr(true);
1865 if (RD->hasAttr<DLLImportAttr>())
1866 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1867 else if (RD->hasAttr<DLLExportAttr>())
1868 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1870 if (!GV->hasExternalLinkage())
1871 emitVBTableDefinition(VBT, RD, GV);
1876 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1877 const CXXRecordDecl *RD,
1878 llvm::GlobalVariable *GV) const {
1879 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1881 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1882 "should only emit vbtables for classes with vbtables");
1884 const ASTRecordLayout &BaseLayout =
1885 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1886 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1888 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1891 // The offset from ReusingBase's vbptr to itself always leads.
1892 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1893 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1895 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1896 for (const auto &I : ReusingBase->vbases()) {
1897 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1898 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1899 assert(!Offset.isNegative());
1901 // Make it relative to the subobject vbptr.
1902 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1903 if (VBT.getVBaseWithVPtr())
1904 CompleteVBPtrOffset +=
1905 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1906 Offset -= CompleteVBPtrOffset;
1908 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1909 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1910 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1913 assert(Offsets.size() ==
1914 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1915 ->getElementType())->getNumElements());
1916 llvm::ArrayType *VBTableType =
1917 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1918 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1919 GV->setInitializer(Init);
1922 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1924 const ThisAdjustment &TA) {
1928 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1930 if (!TA.Virtual.isEmpty()) {
1931 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1932 // Adjust the this argument based on the vtordisp value.
1933 llvm::Value *VtorDispPtr =
1934 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1936 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1937 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1938 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1940 if (TA.Virtual.Microsoft.VBPtrOffset) {
1941 // If the final overrider is defined in a virtual base other than the one
1942 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1943 // the vbtable of the derived class.
1944 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1945 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1947 llvm::Value *VBaseOffset =
1948 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1949 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1950 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1954 if (TA.NonVirtual) {
1955 // Non-virtual adjustment might result in a pointer outside the allocated
1956 // object, e.g. if the final overrider class is laid out after the virtual
1957 // base that declares a method in the most derived class.
1958 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1961 // Don't need to bitcast back, the call CodeGen will handle this.
1966 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1967 const ReturnAdjustment &RA) {
1971 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1973 if (RA.Virtual.Microsoft.VBIndex) {
1974 assert(RA.Virtual.Microsoft.VBIndex > 0);
1975 const ASTContext &Context = getContext();
1976 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
1978 llvm::Value *VBaseOffset =
1979 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1980 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1981 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1985 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
1987 // Cast back to the original type.
1988 return CGF.Builder.CreateBitCast(V, Ret->getType());
1991 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1992 QualType elementType) {
1993 // Microsoft seems to completely ignore the possibility of a
1994 // two-argument usual deallocation function.
1995 return elementType.isDestructedType();
1998 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1999 // Microsoft seems to completely ignore the possibility of a
2000 // two-argument usual deallocation function.
2001 return expr->getAllocatedType().isDestructedType();
2004 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
2005 // The array cookie is always a size_t; we then pad that out to the
2006 // alignment of the element type.
2007 ASTContext &Ctx = getContext();
2008 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
2009 Ctx.getTypeAlignInChars(type));
2012 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
2013 llvm::Value *allocPtr,
2014 CharUnits cookieSize) {
2015 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
2016 llvm::Value *numElementsPtr =
2017 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
2018 return CGF.Builder.CreateLoad(numElementsPtr);
2021 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
2022 llvm::Value *newPtr,
2023 llvm::Value *numElements,
2024 const CXXNewExpr *expr,
2025 QualType elementType) {
2026 assert(requiresArrayCookie(expr));
2028 // The size of the cookie.
2029 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
2031 // Compute an offset to the cookie.
2032 llvm::Value *cookiePtr = newPtr;
2034 // Write the number of elements into the appropriate slot.
2035 unsigned AS = newPtr->getType()->getPointerAddressSpace();
2036 llvm::Value *numElementsPtr
2037 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
2038 CGF.Builder.CreateStore(numElements, numElementsPtr);
2040 // Finally, compute a pointer to the actual data buffer by skipping
2041 // over the cookie completely.
2042 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
2043 cookieSize.getQuantity());
2046 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
2047 llvm::Constant *Dtor,
2048 llvm::Constant *Addr) {
2049 // Create a function which calls the destructor.
2050 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
2052 // extern "C" int __tlregdtor(void (*f)(void));
2053 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
2054 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
2056 llvm::Constant *TLRegDtor =
2057 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
2058 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
2059 TLRegDtorFn->setDoesNotThrow();
2061 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
2064 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
2065 llvm::Constant *Dtor,
2066 llvm::Constant *Addr) {
2068 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
2070 // The default behavior is to use atexit.
2071 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
2074 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
2076 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
2078 ArrayRef<llvm::Function *> CXXThreadLocalInits,
2079 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
2080 // This will create a GV in the .CRT$XDU section. It will point to our
2081 // initialization function. The CRT will call all of these function
2082 // pointers at start-up time and, eventually, at thread-creation time.
2083 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
2084 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
2085 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
2086 llvm::GlobalVariable::InternalLinkage, InitFunc,
2087 Twine(InitFunc->getName(), "$initializer$"));
2088 InitFuncPtr->setSection(".CRT$XDU");
2089 // This variable has discardable linkage, we have to add it to @llvm.used to
2090 // ensure it won't get discarded.
2091 CGM.addUsedGlobal(InitFuncPtr);
2095 std::vector<llvm::Function *> NonComdatInits;
2096 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
2097 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
2098 llvm::Function *F = CXXThreadLocalInits[I];
2100 // If the GV is already in a comdat group, then we have to join it.
2101 if (llvm::Comdat *C = GV->getComdat())
2102 AddToXDU(F)->setComdat(C);
2104 NonComdatInits.push_back(F);
2107 if (!NonComdatInits.empty()) {
2108 llvm::FunctionType *FTy =
2109 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2110 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2111 FTy, "__tls_init", SourceLocation(),
2113 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2119 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2121 QualType LValType) {
2122 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2126 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2127 StringRef VarName("_Init_thread_epoch");
2128 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2130 auto *GV = new llvm::GlobalVariable(
2131 CGM.getModule(), CGM.IntTy,
2132 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2133 /*Initializer=*/nullptr, VarName,
2134 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2135 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2139 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2140 llvm::FunctionType *FTy =
2141 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2142 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2143 return CGM.CreateRuntimeFunction(
2144 FTy, "_Init_thread_header",
2145 llvm::AttributeSet::get(CGM.getLLVMContext(),
2146 llvm::AttributeSet::FunctionIndex,
2147 llvm::Attribute::NoUnwind));
2150 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2151 llvm::FunctionType *FTy =
2152 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2153 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2154 return CGM.CreateRuntimeFunction(
2155 FTy, "_Init_thread_footer",
2156 llvm::AttributeSet::get(CGM.getLLVMContext(),
2157 llvm::AttributeSet::FunctionIndex,
2158 llvm::Attribute::NoUnwind));
2161 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2162 llvm::FunctionType *FTy =
2163 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2164 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2165 return CGM.CreateRuntimeFunction(
2166 FTy, "_Init_thread_abort",
2167 llvm::AttributeSet::get(CGM.getLLVMContext(),
2168 llvm::AttributeSet::FunctionIndex,
2169 llvm::Attribute::NoUnwind));
2173 struct ResetGuardBit : EHScopeStack::Cleanup {
2174 llvm::GlobalVariable *Guard;
2176 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2177 : Guard(Guard), GuardNum(GuardNum) {}
2179 void Emit(CodeGenFunction &CGF, Flags flags) override {
2180 // Reset the bit in the mask so that the static variable may be
2182 CGBuilderTy &Builder = CGF.Builder;
2183 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2184 llvm::ConstantInt *Mask =
2185 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2186 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2190 struct CallInitThreadAbort : EHScopeStack::Cleanup {
2191 llvm::GlobalVariable *Guard;
2192 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2194 void Emit(CodeGenFunction &CGF, Flags flags) override {
2195 // Calling _Init_thread_abort will reset the guard's state.
2196 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2201 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2202 llvm::GlobalVariable *GV,
2204 // MSVC only uses guards for static locals.
2205 if (!D.isStaticLocal()) {
2206 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2207 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2208 llvm::Function *F = CGF.CurFn;
2209 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2210 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2211 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2215 bool ThreadlocalStatic = D.getTLSKind();
2216 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2218 // Thread-safe static variables which aren't thread-specific have a
2219 // per-variable guard.
2220 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2222 CGBuilderTy &Builder = CGF.Builder;
2223 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2224 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2226 // Get the guard variable for this function if we have one already.
2227 GuardInfo *GI = nullptr;
2228 if (ThreadlocalStatic)
2229 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2230 else if (!ThreadsafeStatic)
2231 GI = &GuardVariableMap[D.getDeclContext()];
2233 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2235 if (D.isExternallyVisible()) {
2236 // Externally visible variables have to be numbered in Sema to properly
2237 // handle unreachable VarDecls.
2238 GuardNum = getContext().getStaticLocalNumber(&D);
2239 assert(GuardNum > 0);
2241 } else if (HasPerVariableGuard) {
2242 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2244 // Non-externally visible variables are numbered here in CodeGen.
2245 GuardNum = GI->BitIndex++;
2248 if (!HasPerVariableGuard && GuardNum >= 32) {
2249 if (D.isExternallyVisible())
2250 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2256 // Mangle the name for the guard.
2257 SmallString<256> GuardName;
2259 llvm::raw_svector_ostream Out(GuardName);
2260 if (HasPerVariableGuard)
2261 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2264 getMangleContext().mangleStaticGuardVariable(&D, Out);
2268 // Create the guard variable with a zero-initializer. Just absorb linkage,
2269 // visibility and dll storage class from the guarded variable.
2271 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2272 GV->getLinkage(), Zero, GuardName.str());
2273 GuardVar->setVisibility(GV->getVisibility());
2274 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2275 if (GuardVar->isWeakForLinker())
2276 GuardVar->setComdat(
2277 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2279 GuardVar->setThreadLocal(true);
2280 if (GI && !HasPerVariableGuard)
2281 GI->Guard = GuardVar;
2284 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2285 "static local from the same function had different linkage");
2287 if (!HasPerVariableGuard) {
2288 // Pseudo code for the test:
2289 // if (!(GuardVar & MyGuardBit)) {
2290 // GuardVar |= MyGuardBit;
2291 // ... initialize the object ...;
2294 // Test our bit from the guard variable.
2295 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2296 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2297 llvm::Value *IsInitialized =
2298 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2299 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2300 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2301 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2303 // Set our bit in the guard variable and emit the initializer and add a global
2304 // destructor if appropriate.
2305 CGF.EmitBlock(InitBlock);
2306 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2307 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2308 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2309 CGF.PopCleanupBlock();
2310 Builder.CreateBr(EndBlock);
2313 CGF.EmitBlock(EndBlock);
2315 // Pseudo code for the test:
2316 // if (TSS > _Init_thread_epoch) {
2317 // _Init_thread_header(&TSS);
2319 // ... initialize the object ...;
2320 // _Init_thread_footer(&TSS);
2324 // The algorithm is almost identical to what can be found in the appendix
2327 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2329 // This BasicBLock determines whether or not we have any work to do.
2330 llvm::LoadInst *FirstGuardLoad =
2331 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2332 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2333 llvm::LoadInst *InitThreadEpoch =
2334 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2335 llvm::Value *IsUninitialized =
2336 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2337 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2338 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2339 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2341 // This BasicBlock attempts to determine whether or not this thread is
2342 // responsible for doing the initialization.
2343 CGF.EmitBlock(AttemptInitBlock);
2344 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2345 llvm::LoadInst *SecondGuardLoad =
2346 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2347 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2348 llvm::Value *ShouldDoInit =
2349 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2350 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2351 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2353 // Ok, we ended up getting selected as the initializing thread.
2354 CGF.EmitBlock(InitBlock);
2355 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2356 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2357 CGF.PopCleanupBlock();
2358 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2359 Builder.CreateBr(EndBlock);
2361 CGF.EmitBlock(EndBlock);
2365 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2366 // Null-ness for function memptrs only depends on the first field, which is
2367 // the function pointer. The rest don't matter, so we can zero initialize.
2368 if (MPT->isMemberFunctionPointer())
2371 // The virtual base adjustment field is always -1 for null, so if we have one
2372 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2373 // valid field offset.
2374 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2375 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2376 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2377 RD->nullFieldOffsetIsZero());
2381 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2382 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2383 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2384 llvm::SmallVector<llvm::Type *, 4> fields;
2385 if (MPT->isMemberFunctionPointer())
2386 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2388 fields.push_back(CGM.IntTy); // FieldOffset
2390 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2392 fields.push_back(CGM.IntTy);
2393 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2394 fields.push_back(CGM.IntTy);
2395 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2396 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2398 if (fields.size() == 1)
2400 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2403 void MicrosoftCXXABI::
2404 GetNullMemberPointerFields(const MemberPointerType *MPT,
2405 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2406 assert(fields.empty());
2407 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2408 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2409 if (MPT->isMemberFunctionPointer()) {
2410 // FunctionPointerOrVirtualThunk
2411 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2413 if (RD->nullFieldOffsetIsZero())
2414 fields.push_back(getZeroInt()); // FieldOffset
2416 fields.push_back(getAllOnesInt()); // FieldOffset
2419 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2421 fields.push_back(getZeroInt());
2422 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2423 fields.push_back(getZeroInt());
2424 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2425 fields.push_back(getAllOnesInt());
2429 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2430 llvm::SmallVector<llvm::Constant *, 4> fields;
2431 GetNullMemberPointerFields(MPT, fields);
2432 if (fields.size() == 1)
2434 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2435 assert(Res->getType() == ConvertMemberPointerType(MPT));
2440 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2441 bool IsMemberFunction,
2442 const CXXRecordDecl *RD,
2443 CharUnits NonVirtualBaseAdjustment,
2444 unsigned VBTableIndex) {
2445 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2447 // Single inheritance class member pointer are represented as scalars instead
2449 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2452 llvm::SmallVector<llvm::Constant *, 4> fields;
2453 fields.push_back(FirstField);
2455 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2456 fields.push_back(llvm::ConstantInt::get(
2457 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2459 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2460 CharUnits Offs = CharUnits::Zero();
2461 if (VBTableIndex && RD->getNumVBases())
2462 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2463 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2466 // The rest of the fields are adjusted by conversions to a more derived class.
2467 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2468 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2470 return llvm::ConstantStruct::getAnon(fields);
2474 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2476 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2477 llvm::Constant *FirstField =
2478 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2479 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2480 CharUnits::Zero(), /*VBTableIndex=*/0);
2483 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2485 const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
2486 const ValueDecl *MPD = MP.getMemberPointerDecl();
2488 return EmitNullMemberPointer(DstTy);
2490 ASTContext &Ctx = getContext();
2491 ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
2494 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
2495 C = EmitMemberFunctionPointer(MD);
2497 CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
2498 C = EmitMemberDataPointer(DstTy, FieldOffset);
2501 if (!MemberPointerPath.empty()) {
2502 const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
2503 const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
2504 const MemberPointerType *SrcTy =
2505 Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
2506 ->castAs<MemberPointerType>();
2508 bool DerivedMember = MP.isMemberPointerToDerivedMember();
2509 SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
2510 const CXXRecordDecl *PrevRD = SrcRD;
2511 for (const CXXRecordDecl *PathElem : MemberPointerPath) {
2512 const CXXRecordDecl *Base = nullptr;
2513 const CXXRecordDecl *Derived = nullptr;
2514 if (DerivedMember) {
2521 for (const CXXBaseSpecifier &BS : Derived->bases())
2522 if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
2523 Base->getCanonicalDecl())
2524 DerivedToBasePath.push_back(&BS);
2527 assert(DerivedToBasePath.size() == MemberPointerPath.size());
2529 CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
2530 : CK_BaseToDerivedMemberPointer;
2531 C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
2532 DerivedToBasePath.end(), C);
2538 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
2539 assert(MD->isInstance() && "Member function must not be static!");
2541 MD = MD->getCanonicalDecl();
2542 CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
2543 const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
2544 CodeGenTypes &Types = CGM.getTypes();
2546 unsigned VBTableIndex = 0;
2547 llvm::Constant *FirstField;
2548 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2549 if (!MD->isVirtual()) {
2551 // Check whether the function has a computable LLVM signature.
2552 if (Types.isFuncTypeConvertible(FPT)) {
2553 // The function has a computable LLVM signature; use the correct type.
2554 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2556 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2557 // function type is incomplete.
2560 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2561 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2563 auto &VTableContext = CGM.getMicrosoftVTableContext();
2564 MicrosoftVTableContext::MethodVFTableLocation ML =
2565 VTableContext.getMethodVFTableLocation(MD);
2566 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2567 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2568 // Include the vfptr adjustment if the method is in a non-primary vftable.
2569 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2571 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2574 // The rest of the fields are common with data member pointers.
2575 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2576 NonVirtualBaseAdjustment, VBTableIndex);
2579 /// Member pointers are the same if they're either bitwise identical *or* both
2580 /// null. Null-ness for function members is determined by the first field,
2581 /// while for data member pointers we must compare all fields.
2583 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2586 const MemberPointerType *MPT,
2588 CGBuilderTy &Builder = CGF.Builder;
2590 // Handle != comparisons by switching the sense of all boolean operations.
2591 llvm::ICmpInst::Predicate Eq;
2592 llvm::Instruction::BinaryOps And, Or;
2594 Eq = llvm::ICmpInst::ICMP_NE;
2595 And = llvm::Instruction::Or;
2596 Or = llvm::Instruction::And;
2598 Eq = llvm::ICmpInst::ICMP_EQ;
2599 And = llvm::Instruction::And;
2600 Or = llvm::Instruction::Or;
2603 // If this is a single field member pointer (single inheritance), this is a
2605 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2606 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2607 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2609 return Builder.CreateICmp(Eq, L, R);
2611 // Compare the first field.
2612 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2613 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2614 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2616 // Compare everything other than the first field.
2617 llvm::Value *Res = nullptr;
2618 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2619 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2620 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2621 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2622 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2624 Res = Builder.CreateBinOp(And, Res, Cmp);
2629 // Check if the first field is 0 if this is a function pointer.
2630 if (MPT->isMemberFunctionPointer()) {
2631 // (l1 == r1 && ...) || l0 == 0
2632 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2633 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2634 Res = Builder.CreateBinOp(Or, Res, IsZero);
2637 // Combine the comparison of the first field, which must always be true for
2638 // this comparison to succeeed.
2639 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2643 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2644 llvm::Value *MemPtr,
2645 const MemberPointerType *MPT) {
2646 CGBuilderTy &Builder = CGF.Builder;
2647 llvm::SmallVector<llvm::Constant *, 4> fields;
2648 // We only need one field for member functions.
2649 if (MPT->isMemberFunctionPointer())
2650 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2652 GetNullMemberPointerFields(MPT, fields);
2653 assert(!fields.empty());
2654 llvm::Value *FirstField = MemPtr;
2655 if (MemPtr->getType()->isStructTy())
2656 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2657 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2659 // For function member pointers, we only need to test the function pointer
2660 // field. The other fields if any can be garbage.
2661 if (MPT->isMemberFunctionPointer())
2664 // Otherwise, emit a series of compares and combine the results.
2665 for (int I = 1, E = fields.size(); I < E; ++I) {
2666 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2667 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2668 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2673 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2674 llvm::Constant *Val) {
2675 // Function pointers are null if the pointer in the first field is null.
2676 if (MPT->isMemberFunctionPointer()) {
2677 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2678 Val->getAggregateElement(0U) : Val;
2679 return FirstField->isNullValue();
2682 // If it's not a function pointer and it's zero initializable, we can easily
2684 if (isZeroInitializable(MPT) && Val->isNullValue())
2687 // Otherwise, break down all the fields for comparison. Hopefully these
2688 // little Constants are reused, while a big null struct might not be.
2689 llvm::SmallVector<llvm::Constant *, 4> Fields;
2690 GetNullMemberPointerFields(MPT, Fields);
2691 if (Fields.size() == 1) {
2692 assert(Val->getType()->isIntegerTy());
2693 return Val == Fields[0];
2697 for (I = 0, E = Fields.size(); I != E; ++I) {
2698 if (Val->getAggregateElement(I) != Fields[I])
2705 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2707 llvm::Value *VBPtrOffset,
2708 llvm::Value *VBTableOffset,
2709 llvm::Value **VBPtrOut) {
2710 CGBuilderTy &Builder = CGF.Builder;
2711 // Load the vbtable pointer from the vbptr in the instance.
2712 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2713 llvm::Value *VBPtr =
2714 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2715 if (VBPtrOut) *VBPtrOut = VBPtr;
2716 VBPtr = Builder.CreateBitCast(VBPtr,
2717 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2718 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2720 // Translate from byte offset to table index. It improves analyzability.
2721 llvm::Value *VBTableIndex = Builder.CreateAShr(
2722 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2723 "vbtindex", /*isExact=*/true);
2725 // Load an i32 offset from the vb-table.
2726 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2727 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2728 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2731 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2733 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2734 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2735 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2736 CGBuilderTy &Builder = CGF.Builder;
2737 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2738 llvm::BasicBlock *OriginalBB = nullptr;
2739 llvm::BasicBlock *SkipAdjustBB = nullptr;
2740 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2742 // In the unspecified inheritance model, there might not be a vbtable at all,
2743 // in which case we need to skip the virtual base lookup. If there is a
2744 // vbtable, the first entry is a no-op entry that gives back the original
2745 // base, so look for a virtual base adjustment offset of zero.
2747 OriginalBB = Builder.GetInsertBlock();
2748 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2749 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2750 llvm::Value *IsVirtual =
2751 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2753 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2754 CGF.EmitBlock(VBaseAdjustBB);
2757 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2758 // know the vbptr offset.
2760 CharUnits offs = CharUnits::Zero();
2761 if (!RD->hasDefinition()) {
2762 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2763 unsigned DiagID = Diags.getCustomDiagID(
2764 DiagnosticsEngine::Error,
2765 "member pointer representation requires a "
2766 "complete class type for %0 to perform this expression");
2767 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2768 } else if (RD->getNumVBases())
2769 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2770 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2772 llvm::Value *VBPtr = nullptr;
2773 llvm::Value *VBaseOffs =
2774 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2775 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2777 // Merge control flow with the case where we didn't have to adjust.
2778 if (VBaseAdjustBB) {
2779 Builder.CreateBr(SkipAdjustBB);
2780 CGF.EmitBlock(SkipAdjustBB);
2781 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2782 Phi->addIncoming(Base, OriginalBB);
2783 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2786 return AdjustedBase;
2789 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2790 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2791 const MemberPointerType *MPT) {
2792 assert(MPT->isMemberDataPointer());
2793 unsigned AS = Base->getType()->getPointerAddressSpace();
2795 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2796 CGBuilderTy &Builder = CGF.Builder;
2797 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2798 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2800 // Extract the fields we need, regardless of model. We'll apply them if we
2802 llvm::Value *FieldOffset = MemPtr;
2803 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2804 llvm::Value *VBPtrOffset = nullptr;
2805 if (MemPtr->getType()->isStructTy()) {
2806 // We need to extract values.
2808 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2809 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2810 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2811 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2812 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2815 if (VirtualBaseAdjustmentOffset) {
2816 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2821 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2823 // Apply the offset, which we assume is non-null.
2825 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2827 // Cast the address to the appropriate pointer type, adopting the address
2828 // space of the base pointer.
2829 return Builder.CreateBitCast(Addr, PType);
2832 static MSInheritanceAttr::Spelling
2833 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2834 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2838 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2841 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2842 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2843 E->getCastKind() == CK_ReinterpretMemberPointer);
2845 // Use constant emission if we can.
2846 if (isa<llvm::Constant>(Src))
2847 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2849 // We may be adding or dropping fields from the member pointer, so we need
2850 // both types and the inheritance models of both records.
2851 const MemberPointerType *SrcTy =
2852 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2853 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2854 bool IsFunc = SrcTy->isMemberFunctionPointer();
2856 // If the classes use the same null representation, reinterpret_cast is a nop.
2857 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2858 if (IsReinterpret && IsFunc)
2861 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2862 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2863 if (IsReinterpret &&
2864 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2867 CGBuilderTy &Builder = CGF.Builder;
2869 // Branch past the conversion if Src is null.
2870 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2871 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2873 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2874 // pointer value of the destination type.
2875 if (IsReinterpret) {
2876 // For reinterpret casts, sema ensures that src and dst are both functions
2877 // or data and have the same size, which means the LLVM types should match.
2878 assert(Src->getType() == DstNull->getType());
2879 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2882 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2883 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2884 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2885 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2886 CGF.EmitBlock(ConvertBB);
2889 llvm::Value *FirstField = Src;
2890 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2891 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2892 llvm::Value *VBPtrOffset = nullptr;
2893 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2894 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2895 // We need to extract values.
2897 FirstField = Builder.CreateExtractValue(Src, I++);
2898 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2899 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2900 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2901 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2902 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2903 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2906 // For data pointers, we adjust the field offset directly. For functions, we
2907 // have a separate field.
2908 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2910 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2911 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2912 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2913 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2914 NVAdjustField = getZeroInt();
2915 if (isDerivedToBase)
2916 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2918 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2921 // FIXME PR15713: Support conversions through virtually derived classes.
2923 // Recompose dst from the null struct and the adjusted fields from src.
2924 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2926 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2929 Dst = llvm::UndefValue::get(DstNull->getType());
2931 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2932 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2933 Dst = Builder.CreateInsertValue(
2934 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2935 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2936 Dst = Builder.CreateInsertValue(
2937 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2938 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2939 Dst = Builder.CreateInsertValue(
2940 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2942 Builder.CreateBr(ContinueBB);
2944 // In the continuation, choose between DstNull and Dst.
2945 CGF.EmitBlock(ContinueBB);
2946 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2947 Phi->addIncoming(DstNull, OriginalBB);
2948 Phi->addIncoming(Dst, ConvertBB);
2953 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2954 llvm::Constant *Src) {
2955 const MemberPointerType *SrcTy =
2956 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2957 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2959 CastKind CK = E->getCastKind();
2961 return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
2962 E->path_end(), Src);
2965 llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
2966 const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
2967 CastExpr::path_const_iterator PathBegin,
2968 CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
2969 assert(CK == CK_DerivedToBaseMemberPointer ||
2970 CK == CK_BaseToDerivedMemberPointer ||
2971 CK == CK_ReinterpretMemberPointer);
2972 // If src is null, emit a new null for dst. We can't return src because dst
2973 // might have a new representation.
2974 if (MemberPointerConstantIsNull(SrcTy, Src))
2975 return EmitNullMemberPointer(DstTy);
2977 // We don't need to do anything for reinterpret_casts of non-null member
2978 // pointers. We should only get here when the two type representations have
2980 if (CK == CK_ReinterpretMemberPointer)
2983 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2984 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2987 llvm::Constant *FirstField = Src;
2988 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2989 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2990 llvm::Constant *VBPtrOffset = nullptr;
2991 bool IsFunc = SrcTy->isMemberFunctionPointer();
2992 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2993 // We need to extract values.
2995 FirstField = Src->getAggregateElement(I++);
2996 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2997 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2998 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2999 VBPtrOffset = Src->getAggregateElement(I++);
3000 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
3001 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
3004 // For data pointers, we adjust the field offset directly. For functions, we
3005 // have a separate field.
3006 const MemberPointerType *DerivedTy =
3007 CK == CK_DerivedToBaseMemberPointer ? SrcTy : DstTy;
3008 const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
3009 llvm::Constant *Adj =
3010 CGM.GetNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd);
3012 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
3013 llvm::Constant *&NVAdjustField =
3014 IsFunc ? NonVirtualBaseAdjustment : FirstField;
3015 bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
3016 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
3017 NVAdjustField = getZeroInt();
3018 if (IsDerivedToBase)
3019 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
3021 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
3024 // FIXME PR15713: Support conversions through virtually derived classes.
3026 // Recompose dst from the null struct and the adjusted fields from src.
3027 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
3030 llvm::SmallVector<llvm::Constant *, 4> Fields;
3031 Fields.push_back(FirstField);
3032 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
3033 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
3034 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
3035 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
3036 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
3037 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
3038 return llvm::ConstantStruct::getAnon(Fields);
3041 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
3042 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
3043 llvm::Value *MemPtr, const MemberPointerType *MPT) {
3044 assert(MPT->isMemberFunctionPointer());
3045 const FunctionProtoType *FPT =
3046 MPT->getPointeeType()->castAs<FunctionProtoType>();
3047 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
3048 llvm::FunctionType *FTy =
3049 CGM.getTypes().GetFunctionType(
3050 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
3051 CGBuilderTy &Builder = CGF.Builder;
3053 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
3055 // Extract the fields we need, regardless of model. We'll apply them if we
3057 llvm::Value *FunctionPointer = MemPtr;
3058 llvm::Value *NonVirtualBaseAdjustment = nullptr;
3059 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
3060 llvm::Value *VBPtrOffset = nullptr;
3061 if (MemPtr->getType()->isStructTy()) {
3062 // We need to extract values.
3064 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
3065 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
3066 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
3067 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
3068 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
3069 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
3070 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
3073 if (VirtualBaseAdjustmentOffset) {
3074 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
3078 if (NonVirtualBaseAdjustment) {
3079 // Apply the adjustment and cast back to the original struct type.
3080 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
3081 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
3082 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
3085 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
3088 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
3089 return new MicrosoftCXXABI(CGM);
3092 // MS RTTI Overview:
3093 // The run time type information emitted by cl.exe contains 5 distinct types of
3094 // structures. Many of them reference each other.
3096 // TypeInfo: Static classes that are returned by typeid.
3098 // CompleteObjectLocator: Referenced by vftables. They contain information
3099 // required for dynamic casting, including OffsetFromTop. They also contain
3100 // a reference to the TypeInfo for the type and a reference to the
3101 // CompleteHierarchyDescriptor for the type.
3103 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
3104 // Used during dynamic_cast to walk a class hierarchy. References a base
3105 // class array and the size of said array.
3107 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
3108 // somewhat of a misnomer because the most derived class is also in the list
3109 // as well as multiple copies of virtual bases (if they occur multiple times
3110 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
3111 // every path in the hierarchy, in pre-order depth first order. Note, we do
3112 // not declare a specific llvm type for BaseClassArray, it's merely an array
3113 // of BaseClassDescriptor pointers.
3115 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
3116 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
3117 // BaseClassArray is. It contains information about a class within a
3118 // hierarchy such as: is this base is ambiguous and what is its offset in the
3119 // vbtable. The names of the BaseClassDescriptors have all of their fields
3120 // mangled into them so they can be aggressively deduplicated by the linker.
3122 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
3123 StringRef MangledName("\01??_7type_info@@6B@");
3124 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
3126 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
3128 llvm::GlobalVariable::ExternalLinkage,
3129 /*Initializer=*/nullptr, MangledName);
3134 /// \brief A Helper struct that stores information about a class in a class
3135 /// hierarchy. The information stored in these structs struct is used during
3136 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
3137 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
3138 // implicit depth first pre-order tree connectivity. getFirstChild and
3139 // getNextSibling allow us to walk the tree efficiently.
3140 struct MSRTTIClass {
3142 IsPrivateOnPath = 1 | 8,
3146 HasHierarchyDescriptor = 64
3148 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3149 uint32_t initialize(const MSRTTIClass *Parent,
3150 const CXXBaseSpecifier *Specifier);
3152 MSRTTIClass *getFirstChild() { return this + 1; }
3153 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3154 return Child + 1 + Child->NumBases;
3157 const CXXRecordDecl *RD, *VirtualRoot;
3158 uint32_t Flags, NumBases, OffsetInVBase;
3161 /// \brief Recursively initialize the base class array.
3162 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3163 const CXXBaseSpecifier *Specifier) {
3164 Flags = HasHierarchyDescriptor;
3166 VirtualRoot = nullptr;
3169 if (Specifier->getAccessSpecifier() != AS_public)
3170 Flags |= IsPrivate | IsPrivateOnPath;
3171 if (Specifier->isVirtual()) {
3176 if (Parent->Flags & IsPrivateOnPath)
3177 Flags |= IsPrivateOnPath;
3178 VirtualRoot = Parent->VirtualRoot;
3179 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3180 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3184 MSRTTIClass *Child = getFirstChild();
3185 for (const CXXBaseSpecifier &Base : RD->bases()) {
3186 NumBases += Child->initialize(this, &Base) + 1;
3187 Child = getNextChild(Child);
3192 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3193 switch (Ty->getLinkage()) {
3195 case InternalLinkage:
3196 case UniqueExternalLinkage:
3197 return llvm::GlobalValue::InternalLinkage;
3199 case VisibleNoLinkage:
3200 case ExternalLinkage:
3201 return llvm::GlobalValue::LinkOnceODRLinkage;
3203 llvm_unreachable("Invalid linkage!");
3206 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3207 /// calls to the module and information about the most derived class in a
3209 struct MSRTTIBuilder {
3211 HasBranchingHierarchy = 1,
3212 HasVirtualBranchingHierarchy = 2,
3213 HasAmbiguousBases = 4
3216 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3217 : CGM(ABI.CGM), Context(CGM.getContext()),
3218 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3219 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3222 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3223 llvm::GlobalVariable *
3224 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3225 llvm::GlobalVariable *getClassHierarchyDescriptor();
3226 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3229 ASTContext &Context;
3230 llvm::LLVMContext &VMContext;
3231 llvm::Module &Module;
3232 const CXXRecordDecl *RD;
3233 llvm::GlobalVariable::LinkageTypes Linkage;
3234 MicrosoftCXXABI &ABI;
3239 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3241 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3242 const CXXRecordDecl *RD) {
3243 Classes.push_back(MSRTTIClass(RD));
3244 for (const CXXBaseSpecifier &Base : RD->bases())
3245 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3248 /// \brief Find ambiguity among base classes.
3250 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3251 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3252 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3253 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3254 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3255 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3256 !VirtualBases.insert(Class->RD).second) {
3257 Class = MSRTTIClass::getNextChild(Class);
3260 if (!UniqueBases.insert(Class->RD).second)
3261 AmbiguousBases.insert(Class->RD);
3264 if (AmbiguousBases.empty())
3266 for (MSRTTIClass &Class : Classes)
3267 if (AmbiguousBases.count(Class.RD))
3268 Class.Flags |= MSRTTIClass::IsAmbiguous;
3271 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3272 SmallString<256> MangledName;
3274 llvm::raw_svector_ostream Out(MangledName);
3275 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3278 // Check to see if we've already declared this ClassHierarchyDescriptor.
3279 if (auto CHD = Module.getNamedGlobal(MangledName))
3282 // Serialize the class hierarchy and initialize the CHD Fields.
3283 SmallVector<MSRTTIClass, 8> Classes;
3284 serializeClassHierarchy(Classes, RD);
3285 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3286 detectAmbiguousBases(Classes);
3288 for (auto Class : Classes) {
3289 if (Class.RD->getNumBases() > 1)
3290 Flags |= HasBranchingHierarchy;
3291 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3292 // believe the field isn't actually used.
3293 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3294 Flags |= HasAmbiguousBases;
3296 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3297 Flags |= HasVirtualBranchingHierarchy;
3298 // These gep indices are used to get the address of the first element of the
3299 // base class array.
3300 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3301 llvm::ConstantInt::get(CGM.IntTy, 0)};
3303 // Forward-declare the class hierarchy descriptor
3304 auto Type = ABI.getClassHierarchyDescriptorType();
3305 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3306 /*Initializer=*/nullptr,
3307 StringRef(MangledName));
3308 if (CHD->isWeakForLinker())
3309 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3311 auto *Bases = getBaseClassArray(Classes);
3313 // Initialize the base class ClassHierarchyDescriptor.
3314 llvm::Constant *Fields[] = {
3315 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3316 llvm::ConstantInt::get(CGM.IntTy, Flags),
3317 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3318 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3319 Bases->getValueType(), Bases,
3320 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3322 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3326 llvm::GlobalVariable *
3327 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3328 SmallString<256> MangledName;
3330 llvm::raw_svector_ostream Out(MangledName);
3331 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3334 // Forward-declare the base class array.
3335 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3336 // mode) bytes of padding. We provide a pointer sized amount of padding by
3337 // adding +1 to Classes.size(). The sections have pointer alignment and are
3338 // marked pick-any so it shouldn't matter.
3339 llvm::Type *PtrType = ABI.getImageRelativeType(
3340 ABI.getBaseClassDescriptorType()->getPointerTo());
3341 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3343 new llvm::GlobalVariable(Module, ArrType,
3344 /*Constant=*/true, Linkage,
3345 /*Initializer=*/nullptr, StringRef(MangledName));
3346 if (BCA->isWeakForLinker())
3347 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3349 // Initialize the BaseClassArray.
3350 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3351 for (MSRTTIClass &Class : Classes)
3352 BaseClassArrayData.push_back(
3353 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3354 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3355 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3359 llvm::GlobalVariable *
3360 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3361 // Compute the fields for the BaseClassDescriptor. They are computed up front
3362 // because they are mangled into the name of the object.
3363 uint32_t OffsetInVBTable = 0;
3364 int32_t VBPtrOffset = -1;
3365 if (Class.VirtualRoot) {
3366 auto &VTableContext = CGM.getMicrosoftVTableContext();
3367 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3368 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3371 SmallString<256> MangledName;
3373 llvm::raw_svector_ostream Out(MangledName);
3374 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3375 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3379 // Check to see if we've already declared this object.
3380 if (auto BCD = Module.getNamedGlobal(MangledName))
3383 // Forward-declare the base class descriptor.
3384 auto Type = ABI.getBaseClassDescriptorType();
3386 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3387 /*Initializer=*/nullptr, StringRef(MangledName));
3388 if (BCD->isWeakForLinker())
3389 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3391 // Initialize the BaseClassDescriptor.
3392 llvm::Constant *Fields[] = {
3393 ABI.getImageRelativeConstant(
3394 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3395 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3396 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3397 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3398 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3399 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3400 ABI.getImageRelativeConstant(
3401 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3403 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3407 llvm::GlobalVariable *
3408 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3409 SmallString<256> MangledName;
3411 llvm::raw_svector_ostream Out(MangledName);
3412 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3415 // Check to see if we've already computed this complete object locator.
3416 if (auto COL = Module.getNamedGlobal(MangledName))
3419 // Compute the fields of the complete object locator.
3420 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3421 int VFPtrOffset = 0;
3422 // The offset includes the vtordisp if one exists.
3423 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3424 if (Context.getASTRecordLayout(RD)
3425 .getVBaseOffsetsMap()
3427 ->second.hasVtorDisp())
3428 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3430 // Forward-declare the complete object locator.
3431 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3432 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3433 /*Initializer=*/nullptr, StringRef(MangledName));
3435 // Initialize the CompleteObjectLocator.
3436 llvm::Constant *Fields[] = {
3437 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3438 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3439 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3440 ABI.getImageRelativeConstant(
3441 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3442 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3443 ABI.getImageRelativeConstant(COL),
3445 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3446 if (!ABI.isImageRelative())
3447 FieldsRef = FieldsRef.drop_back();
3448 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3449 if (COL->isWeakForLinker())
3450 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3454 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3455 bool &IsConst, bool &IsVolatile) {
3456 T = Context.getExceptionObjectType(T);
3458 // C++14 [except.handle]p3:
3459 // A handler is a match for an exception object of type E if [...]
3460 // - the handler is of type cv T or const T& where T is a pointer type and
3461 // E is a pointer type that can be converted to T by [...]
3462 // - a qualification conversion
3465 QualType PointeeType = T->getPointeeType();
3466 if (!PointeeType.isNull()) {
3467 IsConst = PointeeType.isConstQualified();
3468 IsVolatile = PointeeType.isVolatileQualified();
3471 // Member pointer types like "const int A::*" are represented by having RTTI
3472 // for "int A::*" and separately storing the const qualifier.
3473 if (const auto *MPTy = T->getAs<MemberPointerType>())
3474 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3477 // Pointer types like "const int * const *" are represented by having RTTI
3478 // for "const int **" and separately storing the const qualifier.
3479 if (T->isPointerType())
3480 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3486 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3487 QualType CatchHandlerType) {
3488 // TypeDescriptors for exceptions never have qualified pointer types,
3489 // qualifiers are stored seperately in order to support qualification
3491 bool IsConst, IsVolatile;
3492 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3494 bool IsReference = CatchHandlerType->isReferenceType();
3504 SmallString<256> MangledName;
3506 llvm::raw_svector_ostream Out(MangledName);
3507 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3510 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3511 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3513 llvm::Constant *Fields[] = {
3514 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3515 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3517 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3518 auto *Var = new llvm::GlobalVariable(
3519 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3520 llvm::GlobalValue::PrivateLinkage,
3521 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3522 StringRef(MangledName));
3523 Var->setUnnamedAddr(true);
3524 Var->setSection("llvm.metadata");
3528 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3529 /// llvm::GlobalVariable * because different type descriptors have different
3530 /// types, and need to be abstracted. They are abstracting by casting the
3531 /// address to an Int8PtrTy.
3532 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3533 SmallString<256> MangledName;
3535 llvm::raw_svector_ostream Out(MangledName);
3536 getMangleContext().mangleCXXRTTI(Type, Out);
3539 // Check to see if we've already declared this TypeDescriptor.
3540 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3541 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3543 // Compute the fields for the TypeDescriptor.
3544 SmallString<256> TypeInfoString;
3546 llvm::raw_svector_ostream Out(TypeInfoString);
3547 getMangleContext().mangleCXXRTTIName(Type, Out);
3550 // Declare and initialize the TypeDescriptor.
3551 llvm::Constant *Fields[] = {
3552 getTypeInfoVTable(CGM), // VFPtr
3553 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3554 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3555 llvm::StructType *TypeDescriptorType =
3556 getTypeDescriptorType(TypeInfoString);
3557 auto *Var = new llvm::GlobalVariable(
3558 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3559 getLinkageForRTTI(Type),
3560 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3561 StringRef(MangledName));
3562 if (Var->isWeakForLinker())
3563 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3564 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3567 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3568 llvm::GlobalVariable *
3569 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3570 const VPtrInfo *Info) {
3571 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3574 static void emitCXXConstructor(CodeGenModule &CGM,
3575 const CXXConstructorDecl *ctor,
3576 StructorType ctorType) {
3577 // There are no constructor variants, always emit the complete destructor.
3578 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3579 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3582 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3583 StructorType dtorType) {
3584 // The complete destructor is equivalent to the base destructor for
3585 // classes with no virtual bases, so try to emit it as an alias.
3586 if (!dtor->getParent()->getNumVBases() &&
3587 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3588 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3589 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3590 if (ProducedAlias) {
3591 if (dtorType == StructorType::Complete)
3593 if (dtor->isVirtual())
3594 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3598 // The base destructor is equivalent to the base destructor of its
3599 // base class if there is exactly one non-virtual base class with a
3600 // non-trivial destructor, there are no fields with a non-trivial
3601 // destructor, and the body of the destructor is trivial.
3602 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3605 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3606 if (Fn->isWeakForLinker())
3607 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3610 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3611 StructorType Type) {
3612 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3613 emitCXXConstructor(CGM, CD, Type);
3616 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3620 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3622 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3624 // Calculate the mangled name.
3625 SmallString<256> ThunkName;
3626 llvm::raw_svector_ostream Out(ThunkName);
3627 getMangleContext().mangleCXXCtor(CD, CT, Out);
3630 // If the thunk has been generated previously, just return it.
3631 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3632 return cast<llvm::Function>(GV);
3634 // Create the llvm::Function.
3635 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3636 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3637 const CXXRecordDecl *RD = CD->getParent();
3638 QualType RecordTy = getContext().getRecordType(RD);
3639 llvm::Function *ThunkFn = llvm::Function::Create(
3640 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3641 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3642 FnInfo.getEffectiveCallingConvention()));
3643 bool IsCopy = CT == Ctor_CopyingClosure;
3646 CodeGenFunction CGF(CGM);
3647 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3649 // Build FunctionArgs.
3650 FunctionArgList FunctionArgs;
3652 // A constructor always starts with a 'this' pointer as its first argument.
3653 buildThisParam(CGF, FunctionArgs);
3655 // Following the 'this' pointer is a reference to the source object that we
3656 // are copying from.
3657 ImplicitParamDecl SrcParam(
3658 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3659 getContext().getLValueReferenceType(RecordTy,
3660 /*SpelledAsLValue=*/true));
3662 FunctionArgs.push_back(&SrcParam);
3664 // Constructors for classes which utilize virtual bases have an additional
3665 // parameter which indicates whether or not it is being delegated to by a more
3666 // derived constructor.
3667 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3668 &getContext().Idents.get("is_most_derived"),
3669 getContext().IntTy);
3670 // Only add the parameter to the list if thie class has virtual bases.
3671 if (RD->getNumVBases() > 0)
3672 FunctionArgs.push_back(&IsMostDerived);
3674 // Start defining the function.
3675 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3676 FunctionArgs, CD->getLocation(), SourceLocation());
3678 llvm::Value *This = getThisValue(CGF);
3680 llvm::Value *SrcVal =
3681 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3686 // Push the this ptr.
3687 Args.add(RValue::get(This), CD->getThisType(getContext()));
3689 // Push the src ptr.
3691 Args.add(RValue::get(SrcVal), SrcParam.getType());
3693 // Add the rest of the default arguments.
3694 std::vector<Stmt *> ArgVec;
3695 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3696 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3697 assert(DefaultArg && "sema forgot to instantiate default args");
3698 ArgVec.push_back(DefaultArg);
3701 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3703 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3704 ConstExprIterator ArgBegin(ArgVec.data()),
3705 ArgEnd(ArgVec.data() + ArgVec.size());
3706 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3708 // Insert any ABI-specific implicit constructor arguments.
3709 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3710 /*ForVirtualBase=*/false,
3711 /*Delegating=*/false, Args);
3713 // Call the destructor with our arguments.
3714 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3715 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3716 Args, CD, Ctor_Complete, ExtraArgs);
3717 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3719 Cleanups.ForceCleanup();
3721 // Emit the ret instruction, remove any temporary instructions created for the
3723 CGF.FinishFunction(SourceLocation());
3728 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3730 int32_t VBPtrOffset,
3732 assert(!T->isReferenceType());
3734 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3735 const CXXConstructorDecl *CD =
3736 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3737 CXXCtorType CT = Ctor_Complete;
3739 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3740 CT = Ctor_CopyingClosure;
3742 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3743 SmallString<256> MangledName;
3745 llvm::raw_svector_ostream Out(MangledName);
3746 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3747 VBPtrOffset, VBIndex, Out);
3749 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3750 return getImageRelativeConstant(GV);
3752 // The TypeDescriptor is used by the runtime to determine if a catch handler
3753 // is appropriate for the exception object.
3754 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3756 // The runtime is responsible for calling the copy constructor if the
3757 // exception is caught by value.
3758 llvm::Constant *CopyCtor;
3760 if (CT == Ctor_CopyingClosure)
3761 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3763 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3765 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3767 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3769 CopyCtor = getImageRelativeConstant(CopyCtor);
3771 bool IsScalar = !RD;
3772 bool HasVirtualBases = false;
3773 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3774 QualType PointeeType = T;
3775 if (T->isPointerType())
3776 PointeeType = T->getPointeeType();
3777 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3778 HasVirtualBases = RD->getNumVBases() > 0;
3779 if (IdentifierInfo *II = RD->getIdentifier())
3780 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3783 // Encode the relevant CatchableType properties into the Flags bitfield.
3784 // FIXME: Figure out how bits 2 or 8 can get set.
3788 if (HasVirtualBases)
3793 llvm::Constant *Fields[] = {
3794 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3795 TD, // TypeDescriptor
3796 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3797 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3798 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3799 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3800 CopyCtor // CopyCtor
3802 llvm::StructType *CTType = getCatchableTypeType();
3803 auto *GV = new llvm::GlobalVariable(
3804 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3805 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3806 GV->setUnnamedAddr(true);
3807 GV->setSection(".xdata");
3808 if (GV->isWeakForLinker())
3809 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3810 return getImageRelativeConstant(GV);
3813 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3814 assert(!T->isReferenceType());
3816 // See if we've already generated a CatchableTypeArray for this type before.
3817 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3821 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3822 // using a SmallSetVector. Duplicates may arise due to virtual bases
3823 // occurring more than once in the hierarchy.
3824 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3826 // C++14 [except.handle]p3:
3827 // A handler is a match for an exception object of type E if [...]
3828 // - the handler is of type cv T or cv T& and T is an unambiguous public
3829 // base class of E, or
3830 // - the handler is of type cv T or const T& where T is a pointer type and
3831 // E is a pointer type that can be converted to T by [...]
3832 // - a standard pointer conversion (4.10) not involving conversions to
3833 // pointers to private or protected or ambiguous classes
3834 const CXXRecordDecl *MostDerivedClass = nullptr;
3835 bool IsPointer = T->isPointerType();
3837 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3839 MostDerivedClass = T->getAsCXXRecordDecl();
3841 // Collect all the unambiguous public bases of the MostDerivedClass.
3842 if (MostDerivedClass) {
3843 const ASTContext &Context = getContext();
3844 const ASTRecordLayout &MostDerivedLayout =
3845 Context.getASTRecordLayout(MostDerivedClass);
3846 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3847 SmallVector<MSRTTIClass, 8> Classes;
3848 serializeClassHierarchy(Classes, MostDerivedClass);
3849 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3850 detectAmbiguousBases(Classes);
3851 for (const MSRTTIClass &Class : Classes) {
3852 // Skip any ambiguous or private bases.
3854 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3856 // Write down how to convert from a derived pointer to a base pointer.
3857 uint32_t OffsetInVBTable = 0;
3858 int32_t VBPtrOffset = -1;
3859 if (Class.VirtualRoot) {
3861 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3862 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3865 // Turn our record back into a pointer if the exception object is a
3867 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3869 RTTITy = Context.getPointerType(RTTITy);
3870 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3871 VBPtrOffset, OffsetInVBTable));
3875 // C++14 [except.handle]p3:
3876 // A handler is a match for an exception object of type E if
3877 // - The handler is of type cv T or cv T& and E and T are the same type
3878 // (ignoring the top-level cv-qualifiers)
3879 CatchableTypes.insert(getCatchableType(T));
3881 // C++14 [except.handle]p3:
3882 // A handler is a match for an exception object of type E if
3883 // - the handler is of type cv T or const T& where T is a pointer type and
3884 // E is a pointer type that can be converted to T by [...]
3885 // - a standard pointer conversion (4.10) not involving conversions to
3886 // pointers to private or protected or ambiguous classes
3888 // C++14 [conv.ptr]p2:
3889 // A prvalue of type "pointer to cv T," where T is an object type, can be
3890 // converted to a prvalue of type "pointer to cv void".
3891 if (IsPointer && T->getPointeeType()->isObjectType())
3892 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3894 // C++14 [except.handle]p3:
3895 // A handler is a match for an exception object of type E if [...]
3896 // - the handler is of type cv T or const T& where T is a pointer or
3897 // pointer to member type and E is std::nullptr_t.
3899 // We cannot possibly list all possible pointer types here, making this
3900 // implementation incompatible with the standard. However, MSVC includes an
3901 // entry for pointer-to-void in this case. Let's do the same.
3902 if (T->isNullPtrType())
3903 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3905 uint32_t NumEntries = CatchableTypes.size();
3906 llvm::Type *CTType =
3907 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3908 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3909 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3910 llvm::Constant *Fields[] = {
3911 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3912 llvm::ConstantArray::get(
3913 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3914 CatchableTypes.end())) // CatchableTypes
3916 SmallString<256> MangledName;
3918 llvm::raw_svector_ostream Out(MangledName);
3919 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3921 CTA = new llvm::GlobalVariable(
3922 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3923 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3924 CTA->setUnnamedAddr(true);
3925 CTA->setSection(".xdata");
3926 if (CTA->isWeakForLinker())
3927 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3931 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3932 bool IsConst, IsVolatile;
3933 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
3935 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3936 // the exception object may be caught as.
3937 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3938 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3939 // This is used as a component of the mangled name which means that we need to
3940 // know what it is in order to see if we have previously generated the
3942 uint32_t NumEntries =
3943 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3944 ->getLimitedValue();
3946 SmallString<256> MangledName;
3948 llvm::raw_svector_ostream Out(MangledName);
3949 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3953 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3955 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3958 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3959 // be at least as CV qualified. Encode this requirement into the Flags
3967 // The cleanup-function (a destructor) must be called when the exception
3968 // object's lifetime ends.
3969 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3970 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3971 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3972 if (!DtorD->isTrivial())
3973 CleanupFn = llvm::ConstantExpr::getBitCast(
3974 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3976 // This is unused as far as we can tell, initialize it to null.
3977 llvm::Constant *ForwardCompat =
3978 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3979 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3980 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3981 llvm::StructType *TIType = getThrowInfoType();
3982 llvm::Constant *Fields[] = {
3983 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3984 getImageRelativeConstant(CleanupFn), // CleanupFn
3985 ForwardCompat, // ForwardCompat
3986 PointerToCatchableTypes // CatchableTypeArray
3988 auto *GV = new llvm::GlobalVariable(
3989 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3990 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3991 GV->setUnnamedAddr(true);
3992 GV->setSection(".xdata");
3993 if (GV->isWeakForLinker())
3994 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3998 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3999 const Expr *SubExpr = E->getSubExpr();
4000 QualType ThrowType = SubExpr->getType();
4001 // The exception object lives on the stack and it's address is passed to the
4002 // runtime function.
4003 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
4004 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
4007 // The so-called ThrowInfo is used to describe how the exception object may be
4009 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
4011 // Call into the runtime to throw the exception.
4012 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
4013 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);