1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
87 llvm::Constant *getAddrOfCXXCatchDescriptor(QualType Ty) override;
89 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
90 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
91 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
93 llvm::Type *StdTypeInfoPtrTy) override;
95 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
96 QualType SrcRecordTy) override;
98 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
99 QualType SrcRecordTy, QualType DestTy,
100 QualType DestRecordTy,
101 llvm::BasicBlock *CastEnd) override;
103 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
104 QualType SrcRecordTy,
105 QualType DestTy) override;
107 bool EmitBadCastCall(CodeGenFunction &CGF) override;
110 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
111 const CXXRecordDecl *ClassDecl,
112 const CXXRecordDecl *BaseClassDecl) override;
115 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
116 const CXXRecordDecl *RD) override;
118 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
119 const CXXRecordDecl *RD) override;
121 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
123 // Background on MSVC destructors
124 // ==============================
126 // Both Itanium and MSVC ABIs have destructor variants. The variant names
127 // roughly correspond in the following way:
129 // Base -> no name, just ~Class
130 // Complete -> vbase destructor
131 // Deleting -> scalar deleting destructor
132 // vector deleting destructor
134 // The base and complete destructors are the same as in Itanium, although the
135 // complete destructor does not accept a VTT parameter when there are virtual
136 // bases. A separate mechanism involving vtordisps is used to ensure that
137 // virtual methods of destroyed subobjects are not called.
139 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
140 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
141 // pointer points to an array. The scalar deleting destructor assumes that
142 // bit 2 is zero, and therefore does not contain a loop.
144 // For virtual destructors, only one entry is reserved in the vftable, and it
145 // always points to the vector deleting destructor. The vector deleting
146 // destructor is the most general, so it can be used to destroy objects in
147 // place, delete single heap objects, or delete arrays.
149 // A TU defining a non-inline destructor is only guaranteed to emit a base
150 // destructor, and all of the other variants are emitted on an as-needed basis
151 // in COMDATs. Because a non-base destructor can be emitted in a TU that
152 // lacks a definition for the destructor, non-base destructors must always
153 // delegate to or alias the base destructor.
155 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
156 SmallVectorImpl<CanQualType> &ArgTys) override;
158 /// Non-base dtors should be emitted as delegating thunks in this ABI.
159 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
160 CXXDtorType DT) const override {
161 return DT != Dtor_Base;
164 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
166 const CXXRecordDecl *
167 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
168 MD = MD->getCanonicalDecl();
169 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
170 MicrosoftVTableContext::MethodVFTableLocation ML =
171 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
172 // The vbases might be ordered differently in the final overrider object
173 // and the complete object, so the "this" argument may sometimes point to
174 // memory that has no particular type (e.g. past the complete object).
175 // In this case, we just use a generic pointer type.
176 // FIXME: might want to have a more precise type in the non-virtual
177 // multiple inheritance case.
178 if (ML.VBase || !ML.VFPtrOffset.isZero())
181 return MD->getParent();
185 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
187 bool VirtualCall) override;
189 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
190 FunctionArgList &Params) override;
192 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
193 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
195 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
197 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
198 const CXXConstructorDecl *D,
199 CXXCtorType Type, bool ForVirtualBase,
201 CallArgList &Args) override;
203 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
204 CXXDtorType Type, bool ForVirtualBase,
205 bool Delegating, llvm::Value *This) override;
207 void emitVTableDefinitions(CodeGenVTables &CGVT,
208 const CXXRecordDecl *RD) override;
210 llvm::Value *getVTableAddressPointInStructor(
211 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
212 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
213 bool &NeedsVirtualOffset) override;
216 getVTableAddressPointForConstExpr(BaseSubobject Base,
217 const CXXRecordDecl *VTableClass) override;
219 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
220 CharUnits VPtrOffset) override;
222 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
224 llvm::Type *Ty) override;
226 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
227 const CXXDestructorDecl *Dtor,
228 CXXDtorType DtorType,
230 const CXXMemberCallExpr *CE) override;
232 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
233 CallArgList &CallArgs) override {
234 assert(GD.getDtorType() == Dtor_Deleting &&
235 "Only deleting destructor thunks are available in this ABI");
236 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
240 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
242 llvm::GlobalVariable *
243 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
244 llvm::GlobalVariable::LinkageTypes Linkage);
246 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
247 llvm::GlobalVariable *GV) const;
249 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
250 GlobalDecl GD, bool ReturnAdjustment) override {
251 // Never dllimport/dllexport thunks.
252 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
255 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
257 if (Linkage == GVA_Internal)
258 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
259 else if (ReturnAdjustment)
260 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
262 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
265 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
266 const ThisAdjustment &TA) override;
268 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
269 const ReturnAdjustment &RA) override;
271 void EmitThreadLocalInitFuncs(
273 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
275 ArrayRef<llvm::Function *> CXXThreadLocalInits,
276 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
278 bool usesThreadWrapperFunction() const override { return false; }
279 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
280 QualType LValType) override;
282 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
283 llvm::GlobalVariable *DeclPtr,
284 bool PerformInit) override;
285 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
286 llvm::Constant *Dtor, llvm::Constant *Addr) override;
288 // ==== Notes on array cookies =========
290 // MSVC seems to only use cookies when the class has a destructor; a
291 // two-argument usual array deallocation function isn't sufficient.
293 // For example, this code prints "100" and "1":
296 // void *operator new[](size_t sz) {
297 // printf("%u\n", sz);
298 // return malloc(sz);
300 // void operator delete[](void *p, size_t sz) {
301 // printf("%u\n", sz);
306 // A *p = new A[100];
309 // Whereas it prints "104" and "104" if you give A a destructor.
311 bool requiresArrayCookie(const CXXDeleteExpr *expr,
312 QualType elementType) override;
313 bool requiresArrayCookie(const CXXNewExpr *expr) override;
314 CharUnits getArrayCookieSizeImpl(QualType type) override;
315 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
317 llvm::Value *NumElements,
318 const CXXNewExpr *expr,
319 QualType ElementType) override;
320 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
321 llvm::Value *allocPtr,
322 CharUnits cookieSize) override;
324 friend struct MSRTTIBuilder;
326 bool isImageRelative() const {
327 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
330 // 5 routines for constructing the llvm types for MS RTTI structs.
331 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
332 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
333 TDTypeName += llvm::utostr(TypeInfoString.size());
334 llvm::StructType *&TypeDescriptorType =
335 TypeDescriptorTypeMap[TypeInfoString.size()];
336 if (TypeDescriptorType)
337 return TypeDescriptorType;
338 llvm::Type *FieldTypes[] = {
341 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
343 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
344 return TypeDescriptorType;
347 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
348 if (!isImageRelative())
353 llvm::StructType *getBaseClassDescriptorType() {
354 if (BaseClassDescriptorType)
355 return BaseClassDescriptorType;
356 llvm::Type *FieldTypes[] = {
357 getImageRelativeType(CGM.Int8PtrTy),
363 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
365 BaseClassDescriptorType = llvm::StructType::create(
366 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
367 return BaseClassDescriptorType;
370 llvm::StructType *getClassHierarchyDescriptorType() {
371 if (ClassHierarchyDescriptorType)
372 return ClassHierarchyDescriptorType;
373 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
374 ClassHierarchyDescriptorType = llvm::StructType::create(
375 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
376 llvm::Type *FieldTypes[] = {
380 getImageRelativeType(
381 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
383 ClassHierarchyDescriptorType->setBody(FieldTypes);
384 return ClassHierarchyDescriptorType;
387 llvm::StructType *getCompleteObjectLocatorType() {
388 if (CompleteObjectLocatorType)
389 return CompleteObjectLocatorType;
390 CompleteObjectLocatorType = llvm::StructType::create(
391 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
392 llvm::Type *FieldTypes[] = {
396 getImageRelativeType(CGM.Int8PtrTy),
397 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
398 getImageRelativeType(CompleteObjectLocatorType),
400 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
401 if (!isImageRelative())
402 FieldTypesRef = FieldTypesRef.drop_back();
403 CompleteObjectLocatorType->setBody(FieldTypesRef);
404 return CompleteObjectLocatorType;
407 llvm::GlobalVariable *getImageBase() {
408 StringRef Name = "__ImageBase";
409 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
412 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
414 llvm::GlobalValue::ExternalLinkage,
415 /*Initializer=*/nullptr, Name);
418 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
419 if (!isImageRelative())
422 if (PtrVal->isNullValue())
423 return llvm::Constant::getNullValue(CGM.IntTy);
425 llvm::Constant *ImageBaseAsInt =
426 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
427 llvm::Constant *PtrValAsInt =
428 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
429 llvm::Constant *Diff =
430 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
431 /*HasNUW=*/true, /*HasNSW=*/true);
432 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
436 MicrosoftMangleContext &getMangleContext() {
437 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
440 llvm::Constant *getZeroInt() {
441 return llvm::ConstantInt::get(CGM.IntTy, 0);
444 llvm::Constant *getAllOnesInt() {
445 return llvm::Constant::getAllOnesValue(CGM.IntTy);
448 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
449 return C ? C : getZeroInt();
452 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
453 return C ? C : getZeroInt();
456 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
459 GetNullMemberPointerFields(const MemberPointerType *MPT,
460 llvm::SmallVectorImpl<llvm::Constant *> &fields);
462 /// \brief Shared code for virtual base adjustment. Returns the offset from
463 /// the vbptr to the virtual base. Optionally returns the address of the
465 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
467 llvm::Value *VBPtrOffset,
468 llvm::Value *VBTableOffset,
469 llvm::Value **VBPtr = nullptr);
471 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
474 int32_t VBTableOffset,
475 llvm::Value **VBPtr = nullptr) {
476 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
477 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
478 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
479 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
482 std::pair<llvm::Value *, llvm::Value *>
483 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
484 QualType SrcRecordTy);
486 /// \brief Performs a full virtual base adjustment. Used to dereference
487 /// pointers to members of virtual bases.
488 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
489 const CXXRecordDecl *RD, llvm::Value *Base,
490 llvm::Value *VirtualBaseAdjustmentOffset,
491 llvm::Value *VBPtrOffset /* optional */);
493 /// \brief Emits a full member pointer with the fields common to data and
494 /// function member pointers.
495 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
496 bool IsMemberFunction,
497 const CXXRecordDecl *RD,
498 CharUnits NonVirtualBaseAdjustment);
500 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
501 const CXXMethodDecl *MD,
502 CharUnits NonVirtualBaseAdjustment);
504 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
507 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
508 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
510 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
511 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
513 /// \brief Generate a thunk for calling a virtual member function MD.
514 llvm::Function *EmitVirtualMemPtrThunk(
515 const CXXMethodDecl *MD,
516 const MicrosoftVTableContext::MethodVFTableLocation &ML);
519 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
521 bool isZeroInitializable(const MemberPointerType *MPT) override;
523 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
524 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
525 return RD->hasAttr<MSInheritanceAttr>();
528 bool isTypeInfoCalculable(QualType Ty) const override {
529 if (!CGCXXABI::isTypeInfoCalculable(Ty))
531 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
532 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
533 if (!RD->hasAttr<MSInheritanceAttr>())
539 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
541 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
542 CharUnits offset) override;
543 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
544 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
546 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
549 const MemberPointerType *MPT,
550 bool Inequality) override;
552 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
554 const MemberPointerType *MPT) override;
557 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
558 llvm::Value *Base, llvm::Value *MemPtr,
559 const MemberPointerType *MPT) override;
561 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
563 llvm::Value *Src) override;
565 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
566 llvm::Constant *Src) override;
569 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
570 llvm::Value *&This, llvm::Value *MemPtr,
571 const MemberPointerType *MPT) override;
573 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
575 llvm::StructType *getCatchableTypeType() {
576 if (CatchableTypeType)
577 return CatchableTypeType;
578 llvm::Type *FieldTypes[] = {
580 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
581 CGM.IntTy, // NonVirtualAdjustment
582 CGM.IntTy, // OffsetToVBPtr
583 CGM.IntTy, // VBTableIndex
585 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
587 CatchableTypeType = llvm::StructType::create(
588 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
589 return CatchableTypeType;
592 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
593 llvm::StructType *&CatchableTypeArrayType =
594 CatchableTypeArrayTypeMap[NumEntries];
595 if (CatchableTypeArrayType)
596 return CatchableTypeArrayType;
598 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
599 CTATypeName += llvm::utostr(NumEntries);
601 getImageRelativeType(getCatchableTypeType()->getPointerTo());
602 llvm::Type *FieldTypes[] = {
603 CGM.IntTy, // NumEntries
604 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
606 CatchableTypeArrayType =
607 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
608 return CatchableTypeArrayType;
611 llvm::StructType *getThrowInfoType() {
613 return ThrowInfoType;
614 llvm::Type *FieldTypes[] = {
616 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
617 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
618 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
620 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
622 return ThrowInfoType;
625 llvm::Constant *getThrowFn() {
626 // _CxxThrowException is passed an exception object and a ThrowInfo object
627 // which describes the exception.
628 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
629 llvm::FunctionType *FTy =
630 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
631 auto *Fn = cast<llvm::Function>(
632 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
633 // _CxxThrowException is stdcall on 32-bit x86 platforms.
634 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
635 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
639 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
642 llvm::Constant *getCatchableType(QualType T,
643 uint32_t NVOffset = 0,
644 int32_t VBPtrOffset = -1,
645 uint32_t VBIndex = 0);
647 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
649 llvm::GlobalVariable *getThrowInfo(QualType T) override;
652 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
653 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
654 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
655 /// \brief All the vftables that have been referenced.
656 VFTablesMapTy VFTablesMap;
657 VTablesMapTy VTablesMap;
659 /// \brief This set holds the record decls we've deferred vtable emission for.
660 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
663 /// \brief All the vbtables which have been referenced.
664 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
666 /// Info on the global variable used to guard initialization of static locals.
667 /// The BitIndex field is only used for externally invisible declarations.
669 GuardInfo() : Guard(nullptr), BitIndex(0) {}
670 llvm::GlobalVariable *Guard;
674 /// Map from DeclContext to the current guard variable. We assume that the
675 /// AST is visited in source code order.
676 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
678 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
679 llvm::StructType *BaseClassDescriptorType;
680 llvm::StructType *ClassHierarchyDescriptorType;
681 llvm::StructType *CompleteObjectLocatorType;
683 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
685 llvm::StructType *CatchableTypeType;
686 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
687 llvm::StructType *ThrowInfoType;
692 CGCXXABI::RecordArgABI
693 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
694 switch (CGM.getTarget().getTriple().getArch()) {
696 // FIXME: Implement for other architectures.
699 case llvm::Triple::x86:
700 // All record arguments are passed in memory on x86. Decide whether to
701 // construct the object directly in argument memory, or to construct the
702 // argument elsewhere and copy the bytes during the call.
704 // If C++ prohibits us from making a copy, construct the arguments directly
705 // into argument memory.
706 if (!canCopyArgument(RD))
707 return RAA_DirectInMemory;
709 // Otherwise, construct the argument into a temporary and copy the bytes
710 // into the outgoing argument memory.
713 case llvm::Triple::x86_64:
714 // Win64 passes objects with non-trivial copy ctors indirectly.
715 if (RD->hasNonTrivialCopyConstructor())
718 // If an object has a destructor, we'd really like to pass it indirectly
719 // because it allows us to elide copies. Unfortunately, MSVC makes that
720 // impossible for small types, which it will pass in a single register or
721 // stack slot. Most objects with dtors are large-ish, so handle that early.
722 // We can't call out all large objects as being indirect because there are
723 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
724 // how we pass large POD types.
725 if (RD->hasNonTrivialDestructor() &&
726 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
729 // We have a trivial copy constructor or no copy constructors, but we have
730 // to make sure it isn't deleted.
731 bool CopyDeleted = false;
732 for (const CXXConstructorDecl *CD : RD->ctors()) {
733 if (CD->isCopyConstructor()) {
734 assert(CD->isTrivial());
735 // We had at least one undeleted trivial copy ctor. Return directly.
736 if (!CD->isDeleted())
742 // The trivial copy constructor was deleted. Return indirectly.
746 // There were no copy ctors. Return in RAX.
750 llvm_unreachable("invalid enum");
753 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
754 const CXXDeleteExpr *DE,
756 QualType ElementType,
757 const CXXDestructorDecl *Dtor) {
758 // FIXME: Provide a source location here even though there's no
759 // CXXMemberCallExpr for dtor call.
760 bool UseGlobalDelete = DE->isGlobalDelete();
761 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
762 llvm::Value *MDThis =
763 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
765 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
768 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
769 llvm::Value *Args[] = {
770 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
771 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
772 auto *Fn = getThrowFn();
774 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
776 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
780 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
781 CallEndCatchMSVC() {}
782 void Emit(CodeGenFunction &CGF, Flags flags) override {
783 CGF.EmitNounwindRuntimeCall(
784 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
789 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
790 const CXXCatchStmt *S) {
791 // In the MS ABI, the runtime handles the copy, and the catch handler is
792 // responsible for destruction.
793 VarDecl *CatchParam = S->getExceptionDecl();
794 llvm::Value *Exn = CGF.getExceptionFromSlot();
795 llvm::Function *BeginCatch =
796 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
799 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
800 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
801 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
805 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
806 llvm::Value *ParamAddr =
807 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
808 llvm::Value *Args[2] = {Exn, ParamAddr};
809 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
810 // FIXME: Do we really need exceptional endcatch cleanups?
811 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
812 CGF.EmitAutoVarCleanups(var);
815 std::pair<llvm::Value *, llvm::Value *>
816 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
817 QualType SrcRecordTy) {
818 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
819 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
820 const ASTContext &Context = getContext();
822 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
823 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
825 // Perform a base adjustment.
826 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
827 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
828 [&](const CXXBaseSpecifier &Base) {
829 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
830 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
832 llvm::Value *Offset = GetVirtualBaseClassOffset(
833 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
834 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
835 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
836 return std::make_pair(Value, Offset);
839 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
840 QualType SrcRecordTy) {
841 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
843 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
846 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
847 llvm::Value *Argument) {
848 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
849 llvm::FunctionType *FTy =
850 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
851 llvm::Value *Args[] = {Argument};
852 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
853 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
856 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
857 llvm::CallSite Call =
858 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
859 Call.setDoesNotReturn();
860 CGF.Builder.CreateUnreachable();
863 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
864 QualType SrcRecordTy,
865 llvm::Value *ThisPtr,
866 llvm::Type *StdTypeInfoPtrTy) {
868 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
869 return CGF.Builder.CreateBitCast(
870 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
873 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
874 QualType SrcRecordTy) {
875 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
877 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
880 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
881 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
882 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
883 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
885 llvm::Value *SrcRTTI =
886 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
887 llvm::Value *DestRTTI =
888 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
891 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
893 // PVOID __RTDynamicCast(
899 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
900 CGF.Int8PtrTy, CGF.Int32Ty};
901 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
902 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
904 llvm::Value *Args[] = {
905 Value, Offset, SrcRTTI, DestRTTI,
906 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
907 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
908 return CGF.Builder.CreateBitCast(Value, DestLTy);
912 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
913 QualType SrcRecordTy,
916 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
918 // PVOID __RTCastToVoid(
920 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
921 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
922 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
924 llvm::Value *Args[] = {Value};
925 return CGF.EmitRuntimeCall(Function, Args);
928 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
932 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
933 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
934 const CXXRecordDecl *BaseClassDecl) {
935 const ASTContext &Context = getContext();
937 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
938 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
939 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
940 CharUnits VBTableChars =
942 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
943 llvm::Value *VBTableOffset =
944 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
946 llvm::Value *VBPtrToNewBase =
947 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
949 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
950 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
953 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
954 return isa<CXXConstructorDecl>(GD.getDecl());
957 static bool isDeletingDtor(GlobalDecl GD) {
958 return isa<CXXDestructorDecl>(GD.getDecl()) &&
959 GD.getDtorType() == Dtor_Deleting;
962 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
963 return isDeletingDtor(GD);
966 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
967 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
971 if (FI.isInstanceMethod()) {
972 // If it's an instance method, aggregates are always returned indirectly via
973 // the second parameter.
974 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
975 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
977 } else if (!RD->isPOD()) {
978 // If it's a free function, non-POD types are returned indirectly.
979 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
983 // Otherwise, use the C ABI rules.
988 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
989 const CXXRecordDecl *RD) {
990 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
991 assert(IsMostDerivedClass &&
992 "ctor for a class with virtual bases must have an implicit parameter");
993 llvm::Value *IsCompleteObject =
994 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
996 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
997 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
998 CGF.Builder.CreateCondBr(IsCompleteObject,
999 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1001 CGF.EmitBlock(CallVbaseCtorsBB);
1003 // Fill in the vbtable pointers here.
1004 EmitVBPtrStores(CGF, RD);
1006 // CGF will put the base ctor calls in this basic block for us later.
1008 return SkipVbaseCtorsBB;
1011 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1012 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1013 // In most cases, an override for a vbase virtual method can adjust
1014 // the "this" parameter by applying a constant offset.
1015 // However, this is not enough while a constructor or a destructor of some
1016 // class X is being executed if all the following conditions are met:
1017 // - X has virtual bases, (1)
1018 // - X overrides a virtual method M of a vbase Y, (2)
1019 // - X itself is a vbase of the most derived class.
1021 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1022 // which holds the extra amount of "this" adjustment we must do when we use
1023 // the X vftables (i.e. during X ctor or dtor).
1024 // Outside the ctors and dtors, the values of vtorDisps are zero.
1026 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1027 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1028 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1029 CGBuilderTy &Builder = CGF.Builder;
1032 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1033 llvm::Value *Int8This = nullptr; // Initialize lazily.
1035 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1037 if (!I->second.hasVtorDisp())
1040 llvm::Value *VBaseOffset =
1041 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1042 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1043 // just to Trunc back immediately.
1044 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1045 uint64_t ConstantVBaseOffset =
1046 Layout.getVBaseClassOffset(I->first).getQuantity();
1048 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1049 llvm::Value *VtorDispValue = Builder.CreateSub(
1050 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1054 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1055 CGF.Int8Ty->getPointerTo(AS));
1056 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1057 // vtorDisp is always the 32-bits before the vbase in the class layout.
1058 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1059 VtorDispPtr = Builder.CreateBitCast(
1060 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1062 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1066 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1067 const CXXMethodDecl *MD) {
1068 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1069 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1070 CallingConv ActualCallingConv =
1071 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1072 return ExpectedCallingConv == ActualCallingConv;
1075 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1076 // There's only one constructor type in this ABI.
1077 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1079 // Exported default constructors either have a simple call-site where they use
1080 // the typical calling convention and have a single 'this' pointer for an
1081 // argument -or- they get a wrapper function which appropriately thunks to the
1082 // real default constructor. This thunk is the default constructor closure.
1083 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1084 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1085 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1086 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1087 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1091 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1092 const CXXRecordDecl *RD) {
1093 llvm::Value *ThisInt8Ptr =
1094 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1095 const ASTContext &Context = getContext();
1096 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1098 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1099 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1100 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1101 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1102 const ASTRecordLayout &SubobjectLayout =
1103 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1104 CharUnits Offs = VBT->NonVirtualOffset;
1105 Offs += SubobjectLayout.getVBPtrOffset();
1106 if (VBT->getVBaseWithVPtr())
1107 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1108 llvm::Value *VBPtr =
1109 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1110 llvm::Value *GVPtr = CGF.Builder.CreateConstInBoundsGEP2_32(GV, 0, 0);
1111 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1112 "vbptr." + VBT->ReusingBase->getName());
1113 CGF.Builder.CreateStore(GVPtr, VBPtr);
1118 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1119 SmallVectorImpl<CanQualType> &ArgTys) {
1120 // TODO: 'for base' flag
1121 if (T == StructorType::Deleting) {
1122 // The scalar deleting destructor takes an implicit int parameter.
1123 ArgTys.push_back(getContext().IntTy);
1125 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1129 // All parameters are already in place except is_most_derived, which goes
1130 // after 'this' if it's variadic and last if it's not.
1132 const CXXRecordDecl *Class = CD->getParent();
1133 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1134 if (Class->getNumVBases()) {
1135 if (FPT->isVariadic())
1136 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1138 ArgTys.push_back(getContext().IntTy);
1142 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1143 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1144 // other destructor variants are delegating thunks.
1145 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1149 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1150 GD = GD.getCanonicalDecl();
1151 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1153 GlobalDecl LookupGD = GD;
1154 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1155 // Complete destructors take a pointer to the complete object as a
1156 // parameter, thus don't need this adjustment.
1157 if (GD.getDtorType() == Dtor_Complete)
1160 // There's no Dtor_Base in vftable but it shares the this adjustment with
1161 // the deleting one, so look it up instead.
1162 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1165 MicrosoftVTableContext::MethodVFTableLocation ML =
1166 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1167 CharUnits Adjustment = ML.VFPtrOffset;
1169 // Normal virtual instance methods need to adjust from the vfptr that first
1170 // defined the virtual method to the virtual base subobject, but destructors
1171 // do not. The vector deleting destructor thunk applies this adjustment for
1173 if (isa<CXXDestructorDecl>(MD))
1174 Adjustment = CharUnits::Zero();
1177 const ASTRecordLayout &DerivedLayout =
1178 getContext().getASTRecordLayout(MD->getParent());
1179 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1185 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1186 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1188 // If the call of a virtual function is not virtual, we just have to
1189 // compensate for the adjustment the virtual function does in its prologue.
1190 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1191 if (Adjustment.isZero())
1194 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1195 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1196 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1197 assert(Adjustment.isPositive());
1198 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1201 GD = GD.getCanonicalDecl();
1202 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1204 GlobalDecl LookupGD = GD;
1205 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1206 // Complete dtors take a pointer to the complete object,
1207 // thus don't need adjustment.
1208 if (GD.getDtorType() == Dtor_Complete)
1211 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1212 // with the base one, so look up the deleting one instead.
1213 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1215 MicrosoftVTableContext::MethodVFTableLocation ML =
1216 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1218 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1219 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1220 CharUnits StaticOffset = ML.VFPtrOffset;
1222 // Base destructors expect 'this' to point to the beginning of the base
1223 // subobject, not the first vfptr that happens to contain the virtual dtor.
1224 // However, we still need to apply the virtual base adjustment.
1225 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1226 StaticOffset = CharUnits::Zero();
1229 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1230 llvm::Value *VBaseOffset =
1231 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1232 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1234 if (!StaticOffset.isZero()) {
1235 assert(StaticOffset.isPositive());
1236 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1238 // Non-virtual adjustment might result in a pointer outside the allocated
1239 // object, e.g. if the final overrider class is laid out after the virtual
1240 // base that declares a method in the most derived class.
1241 // FIXME: Update the code that emits this adjustment in thunks prologues.
1242 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1244 This = CGF.Builder.CreateConstInBoundsGEP1_32(This,
1245 StaticOffset.getQuantity());
1251 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1253 FunctionArgList &Params) {
1254 ASTContext &Context = getContext();
1255 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1256 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1257 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1258 ImplicitParamDecl *IsMostDerived
1259 = ImplicitParamDecl::Create(Context, nullptr,
1260 CGF.CurGD.getDecl()->getLocation(),
1261 &Context.Idents.get("is_most_derived"),
1263 // The 'most_derived' parameter goes second if the ctor is variadic and last
1264 // if it's not. Dtors can't be variadic.
1265 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1266 if (FPT->isVariadic())
1267 Params.insert(Params.begin() + 1, IsMostDerived);
1269 Params.push_back(IsMostDerived);
1270 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1271 } else if (isDeletingDtor(CGF.CurGD)) {
1272 ImplicitParamDecl *ShouldDelete
1273 = ImplicitParamDecl::Create(Context, nullptr,
1274 CGF.CurGD.getDecl()->getLocation(),
1275 &Context.Idents.get("should_call_delete"),
1277 Params.push_back(ShouldDelete);
1278 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1282 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1283 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1284 // In this ABI, every virtual function takes a pointer to one of the
1285 // subobjects that first defines it as the 'this' parameter, rather than a
1286 // pointer to the final overrider subobject. Thus, we need to adjust it back
1287 // to the final overrider subobject before use.
1288 // See comments in the MicrosoftVFTableContext implementation for the details.
1289 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1290 if (Adjustment.isZero())
1293 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1294 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1295 *thisTy = This->getType();
1297 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1298 assert(Adjustment.isPositive());
1300 CGF.Builder.CreateConstInBoundsGEP1_32(This, -Adjustment.getQuantity());
1301 return CGF.Builder.CreateBitCast(This, thisTy);
1304 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1307 /// If this is a function that the ABI specifies returns 'this', initialize
1308 /// the return slot to 'this' at the start of the function.
1310 /// Unlike the setting of return types, this is done within the ABI
1311 /// implementation instead of by clients of CGCXXABI because:
1312 /// 1) getThisValue is currently protected
1313 /// 2) in theory, an ABI could implement 'this' returns some other way;
1314 /// HasThisReturn only specifies a contract, not the implementation
1315 if (HasThisReturn(CGF.CurGD))
1316 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1317 else if (hasMostDerivedReturn(CGF.CurGD))
1318 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1321 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1322 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1323 assert(getStructorImplicitParamDecl(CGF) &&
1324 "no implicit parameter for a constructor with virtual bases?");
1325 getStructorImplicitParamValue(CGF)
1326 = CGF.Builder.CreateLoad(
1327 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1331 if (isDeletingDtor(CGF.CurGD)) {
1332 assert(getStructorImplicitParamDecl(CGF) &&
1333 "no implicit parameter for a deleting destructor?");
1334 getStructorImplicitParamValue(CGF)
1335 = CGF.Builder.CreateLoad(
1336 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1337 "should_call_delete");
1341 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1342 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1343 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1344 assert(Type == Ctor_Complete || Type == Ctor_Base);
1346 // Check if we need a 'most_derived' parameter.
1347 if (!D->getParent()->getNumVBases())
1350 // Add the 'most_derived' argument second if we are variadic or last if not.
1351 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1352 llvm::Value *MostDerivedArg =
1353 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1354 RValue RV = RValue::get(MostDerivedArg);
1355 if (MostDerivedArg) {
1356 if (FPT->isVariadic())
1357 Args.insert(Args.begin() + 1,
1358 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1360 Args.add(RV, getContext().IntTy);
1363 return 1; // Added one arg.
1366 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1367 const CXXDestructorDecl *DD,
1368 CXXDtorType Type, bool ForVirtualBase,
1369 bool Delegating, llvm::Value *This) {
1370 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1372 if (DD->isVirtual()) {
1373 assert(Type != CXXDtorType::Dtor_Deleting &&
1374 "The deleting destructor should only be called via a virtual call");
1375 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1379 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1380 /*ImplicitParam=*/nullptr,
1381 /*ImplicitParamTy=*/QualType(), nullptr,
1382 getFromDtorType(Type));
1385 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1386 const CXXRecordDecl *RD) {
1387 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1388 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1390 for (VPtrInfo *Info : VFPtrs) {
1391 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1392 if (VTable->hasInitializer())
1395 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1396 ? getMSCompleteObjectLocator(RD, Info)
1399 const VTableLayout &VTLayout =
1400 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1401 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1402 RD, VTLayout.vtable_component_begin(),
1403 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1404 VTLayout.getNumVTableThunks(), RTTI);
1406 VTable->setInitializer(Init);
1410 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1411 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1412 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1413 NeedsVirtualOffset = (NearestVBase != nullptr);
1415 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1416 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1417 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1418 if (!VTableAddressPoint) {
1419 assert(Base.getBase()->getNumVBases() &&
1420 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1422 return VTableAddressPoint;
1425 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1426 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1427 SmallString<256> &Name) {
1428 llvm::raw_svector_ostream Out(Name);
1429 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1432 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1433 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1434 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1435 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1436 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1437 assert(VFTable && "Couldn't find a vftable for the given base?");
1441 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1442 CharUnits VPtrOffset) {
1443 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1444 // shouldn't be used in the given record type. We want to cache this result in
1445 // VFTablesMap, thus a simple zero check is not sufficient.
1446 VFTableIdTy ID(RD, VPtrOffset);
1447 VTablesMapTy::iterator I;
1449 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1453 llvm::GlobalVariable *&VTable = I->second;
1455 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1456 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1458 if (DeferredVFTables.insert(RD).second) {
1459 // We haven't processed this record type before.
1460 // Queue up this v-table for possible deferred emission.
1461 CGM.addDeferredVTable(RD);
1464 // Create all the vftables at once in order to make sure each vftable has
1465 // a unique mangled name.
1466 llvm::StringSet<> ObservedMangledNames;
1467 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1468 SmallString<256> Name;
1469 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1470 if (!ObservedMangledNames.insert(Name.str()).second)
1471 llvm_unreachable("Already saw this mangling before?");
1476 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1477 if (VFPtrs[J]->FullOffsetInMDC != VPtrOffset)
1479 SmallString<256> VFTableName;
1480 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], VFTableName);
1481 StringRef VTableName = VFTableName;
1483 uint64_t NumVTableSlots =
1484 VTContext.getVFTableLayout(RD, VFPtrs[J]->FullOffsetInMDC)
1485 .getNumVTableComponents();
1486 llvm::GlobalValue::LinkageTypes VTableLinkage =
1487 llvm::GlobalValue::ExternalLinkage;
1488 llvm::ArrayType *VTableType =
1489 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1490 if (getContext().getLangOpts().RTTIData) {
1491 VTableLinkage = llvm::GlobalValue::PrivateLinkage;
1495 VTable = CGM.getModule().getNamedGlobal(VFTableName);
1497 // Create a backing variable for the contents of VTable. The VTable may
1498 // or may not include space for a pointer to RTTI data.
1499 llvm::GlobalValue *VFTable = VTable = new llvm::GlobalVariable(
1500 CGM.getModule(), VTableType, /*isConstant=*/true, VTableLinkage,
1501 /*Initializer=*/nullptr, VTableName);
1502 VTable->setUnnamedAddr(true);
1504 // Only insert a pointer into the VFTable for RTTI data if we are not
1505 // importing it. We never reference the RTTI data directly so there is no
1506 // need to make room for it.
1507 if (getContext().getLangOpts().RTTIData &&
1508 !RD->hasAttr<DLLImportAttr>()) {
1509 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1510 llvm::ConstantInt::get(CGM.IntTy, 1)};
1511 // Create a GEP which points just after the first entry in the VFTable,
1512 // this should be the location of the first virtual method.
1513 llvm::Constant *VTableGEP =
1514 llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, GEPIndices);
1515 // The symbol for the VFTable is an alias to the GEP. It is
1516 // transparent, to other modules, what the nature of this symbol is; all
1517 // that matters is that the alias be the address of the first virtual
1519 VFTable = llvm::GlobalAlias::create(
1520 cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(),
1521 /*AddressSpace=*/0, llvm::GlobalValue::ExternalLinkage,
1522 VFTableName.str(), VTableGEP, &CGM.getModule());
1524 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1525 // be referencing any RTTI data. The GlobalVariable will end up being
1526 // an appropriate definition of the VFTable.
1527 VTable->setName(VFTableName.str());
1530 VFTable->setUnnamedAddr(true);
1531 if (RD->hasAttr<DLLImportAttr>())
1532 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1533 else if (RD->hasAttr<DLLExportAttr>())
1534 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1536 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1537 if (VFTable != VTable) {
1538 if (llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage)) {
1539 // AvailableExternally implies that we grabbed the data from another
1540 // executable. No need to stick the alias in a Comdat.
1541 } else if (llvm::GlobalValue::isInternalLinkage(VFTableLinkage) ||
1542 llvm::GlobalValue::isWeakODRLinkage(VFTableLinkage) ||
1543 llvm::GlobalValue::isLinkOnceODRLinkage(VFTableLinkage)) {
1544 // The alias is going to be dropped into a Comdat, no need to make it
1546 if (!llvm::GlobalValue::isInternalLinkage(VFTableLinkage))
1547 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1549 CGM.getModule().getOrInsertComdat(VFTable->getName());
1550 // We must indicate which VFTable is larger to support linking between
1551 // translation units which do and do not have RTTI data. The largest
1552 // VFTable contains the RTTI data; translation units which reference
1553 // the smaller VFTable always reference it relative to the first
1555 C->setSelectionKind(llvm::Comdat::Largest);
1556 VTable->setComdat(C);
1558 llvm_unreachable("unexpected linkage for vftable!");
1561 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage))
1563 CGM.getModule().getOrInsertComdat(VTable->getName()));
1565 VFTable->setLinkage(VFTableLinkage);
1566 CGM.setGlobalVisibility(VFTable, RD);
1567 VFTablesMap[ID] = VFTable;
1575 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1579 GD = GD.getCanonicalDecl();
1580 CGBuilderTy &Builder = CGF.Builder;
1582 Ty = Ty->getPointerTo()->getPointerTo();
1584 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1585 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1587 MicrosoftVTableContext::MethodVFTableLocation ML =
1588 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1589 llvm::Value *VFuncPtr =
1590 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1591 return Builder.CreateLoad(VFuncPtr);
1594 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1595 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1596 llvm::Value *This, const CXXMemberCallExpr *CE) {
1597 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1598 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1600 // We have only one destructor in the vftable but can get both behaviors
1601 // by passing an implicit int parameter.
1602 GlobalDecl GD(Dtor, Dtor_Deleting);
1603 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1604 Dtor, StructorType::Deleting);
1605 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1606 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1608 ASTContext &Context = getContext();
1609 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1610 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1611 DtorType == Dtor_Deleting);
1613 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1614 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1615 ImplicitParam, Context.IntTy, CE,
1616 StructorType::Deleting);
1617 return RV.getScalarVal();
1620 const VBTableGlobals &
1621 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1622 // At this layer, we can key the cache off of a single class, which is much
1623 // easier than caching each vbtable individually.
1624 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1626 std::tie(Entry, Added) =
1627 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1628 VBTableGlobals &VBGlobals = Entry->second;
1632 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1633 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1635 // Cache the globals for all vbtables so we don't have to recompute the
1637 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1638 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1639 E = VBGlobals.VBTables->end();
1641 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1647 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1648 const CXXMethodDecl *MD,
1649 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1650 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1651 "can't form pointers to ctors or virtual dtors");
1653 // Calculate the mangled name.
1654 SmallString<256> ThunkName;
1655 llvm::raw_svector_ostream Out(ThunkName);
1656 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1659 // If the thunk has been generated previously, just return it.
1660 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1661 return cast<llvm::Function>(GV);
1663 // Create the llvm::Function.
1664 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1665 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1666 llvm::Function *ThunkFn =
1667 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1668 ThunkName.str(), &CGM.getModule());
1669 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1671 ThunkFn->setLinkage(MD->isExternallyVisible()
1672 ? llvm::GlobalValue::LinkOnceODRLinkage
1673 : llvm::GlobalValue::InternalLinkage);
1674 if (MD->isExternallyVisible())
1675 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1677 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1678 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1680 // Add the "thunk" attribute so that LLVM knows that the return type is
1681 // meaningless. These thunks can be used to call functions with differing
1682 // return types, and the caller is required to cast the prototype
1683 // appropriately to extract the correct value.
1684 ThunkFn->addFnAttr("thunk");
1686 // These thunks can be compared, so they are not unnamed.
1687 ThunkFn->setUnnamedAddr(false);
1690 CodeGenFunction CGF(CGM);
1691 CGF.CurGD = GlobalDecl(MD);
1692 CGF.CurFuncIsThunk = true;
1694 // Build FunctionArgs, but only include the implicit 'this' parameter
1696 FunctionArgList FunctionArgs;
1697 buildThisParam(CGF, FunctionArgs);
1699 // Start defining the function.
1700 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1701 FunctionArgs, MD->getLocation(), SourceLocation());
1704 // Load the vfptr and then callee from the vftable. The callee should have
1705 // adjusted 'this' so that the vfptr is at offset zero.
1706 llvm::Value *VTable = CGF.GetVTablePtr(
1707 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1708 llvm::Value *VFuncPtr =
1709 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1710 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1712 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1717 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1718 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1719 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1720 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1721 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1722 if (GV->isDeclaration())
1723 emitVBTableDefinition(*VBT, RD, GV);
1727 llvm::GlobalVariable *
1728 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1729 llvm::GlobalVariable::LinkageTypes Linkage) {
1730 SmallString<256> OutName;
1731 llvm::raw_svector_ostream Out(OutName);
1732 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1734 StringRef Name = OutName.str();
1736 llvm::ArrayType *VBTableType =
1737 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1739 assert(!CGM.getModule().getNamedGlobal(Name) &&
1740 "vbtable with this name already exists: mangling bug?");
1741 llvm::GlobalVariable *GV =
1742 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1743 GV->setUnnamedAddr(true);
1745 if (RD->hasAttr<DLLImportAttr>())
1746 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1747 else if (RD->hasAttr<DLLExportAttr>())
1748 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1750 if (!GV->hasExternalLinkage())
1751 emitVBTableDefinition(VBT, RD, GV);
1756 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1757 const CXXRecordDecl *RD,
1758 llvm::GlobalVariable *GV) const {
1759 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1761 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1762 "should only emit vbtables for classes with vbtables");
1764 const ASTRecordLayout &BaseLayout =
1765 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1766 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1768 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1771 // The offset from ReusingBase's vbptr to itself always leads.
1772 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1773 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1775 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1776 for (const auto &I : ReusingBase->vbases()) {
1777 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1778 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1779 assert(!Offset.isNegative());
1781 // Make it relative to the subobject vbptr.
1782 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1783 if (VBT.getVBaseWithVPtr())
1784 CompleteVBPtrOffset +=
1785 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1786 Offset -= CompleteVBPtrOffset;
1788 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1789 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1790 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1793 assert(Offsets.size() ==
1794 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1795 ->getElementType())->getNumElements());
1796 llvm::ArrayType *VBTableType =
1797 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1798 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1799 GV->setInitializer(Init);
1801 // Set the right visibility.
1802 CGM.setGlobalVisibility(GV, RD);
1805 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1807 const ThisAdjustment &TA) {
1811 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1813 if (!TA.Virtual.isEmpty()) {
1814 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1815 // Adjust the this argument based on the vtordisp value.
1816 llvm::Value *VtorDispPtr =
1817 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1819 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1820 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1821 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1823 if (TA.Virtual.Microsoft.VBPtrOffset) {
1824 // If the final overrider is defined in a virtual base other than the one
1825 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1826 // the vbtable of the derived class.
1827 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1828 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1830 llvm::Value *VBaseOffset =
1831 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1832 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1833 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1837 if (TA.NonVirtual) {
1838 // Non-virtual adjustment might result in a pointer outside the allocated
1839 // object, e.g. if the final overrider class is laid out after the virtual
1840 // base that declares a method in the most derived class.
1841 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1844 // Don't need to bitcast back, the call CodeGen will handle this.
1849 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1850 const ReturnAdjustment &RA) {
1854 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1856 if (RA.Virtual.Microsoft.VBIndex) {
1857 assert(RA.Virtual.Microsoft.VBIndex > 0);
1858 const ASTContext &Context = getContext();
1859 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
1861 llvm::Value *VBaseOffset =
1862 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1863 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1864 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1868 V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual);
1870 // Cast back to the original type.
1871 return CGF.Builder.CreateBitCast(V, Ret->getType());
1874 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1875 QualType elementType) {
1876 // Microsoft seems to completely ignore the possibility of a
1877 // two-argument usual deallocation function.
1878 return elementType.isDestructedType();
1881 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1882 // Microsoft seems to completely ignore the possibility of a
1883 // two-argument usual deallocation function.
1884 return expr->getAllocatedType().isDestructedType();
1887 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1888 // The array cookie is always a size_t; we then pad that out to the
1889 // alignment of the element type.
1890 ASTContext &Ctx = getContext();
1891 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1892 Ctx.getTypeAlignInChars(type));
1895 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1896 llvm::Value *allocPtr,
1897 CharUnits cookieSize) {
1898 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1899 llvm::Value *numElementsPtr =
1900 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1901 return CGF.Builder.CreateLoad(numElementsPtr);
1904 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1905 llvm::Value *newPtr,
1906 llvm::Value *numElements,
1907 const CXXNewExpr *expr,
1908 QualType elementType) {
1909 assert(requiresArrayCookie(expr));
1911 // The size of the cookie.
1912 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1914 // Compute an offset to the cookie.
1915 llvm::Value *cookiePtr = newPtr;
1917 // Write the number of elements into the appropriate slot.
1918 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1919 llvm::Value *numElementsPtr
1920 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1921 CGF.Builder.CreateStore(numElements, numElementsPtr);
1923 // Finally, compute a pointer to the actual data buffer by skipping
1924 // over the cookie completely.
1925 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1926 cookieSize.getQuantity());
1929 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
1930 llvm::Constant *Dtor,
1931 llvm::Constant *Addr) {
1932 // Create a function which calls the destructor.
1933 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
1935 // extern "C" int __tlregdtor(void (*f)(void));
1936 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
1937 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
1939 llvm::Constant *TLRegDtor =
1940 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
1941 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
1942 TLRegDtorFn->setDoesNotThrow();
1944 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
1947 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
1948 llvm::Constant *Dtor,
1949 llvm::Constant *Addr) {
1951 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
1953 // The default behavior is to use atexit.
1954 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
1957 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
1959 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
1961 ArrayRef<llvm::Function *> CXXThreadLocalInits,
1962 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
1963 // This will create a GV in the .CRT$XDU section. It will point to our
1964 // initialization function. The CRT will call all of these function
1965 // pointers at start-up time and, eventually, at thread-creation time.
1966 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
1967 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
1968 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
1969 llvm::GlobalVariable::InternalLinkage, InitFunc,
1970 Twine(InitFunc->getName(), "$initializer$"));
1971 InitFuncPtr->setSection(".CRT$XDU");
1972 // This variable has discardable linkage, we have to add it to @llvm.used to
1973 // ensure it won't get discarded.
1974 CGM.addUsedGlobal(InitFuncPtr);
1978 std::vector<llvm::Function *> NonComdatInits;
1979 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
1980 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
1981 llvm::Function *F = CXXThreadLocalInits[I];
1983 // If the GV is already in a comdat group, then we have to join it.
1984 if (llvm::Comdat *C = GV->getComdat())
1985 AddToXDU(F)->setComdat(C);
1987 NonComdatInits.push_back(F);
1990 if (!NonComdatInits.empty()) {
1991 llvm::FunctionType *FTy =
1992 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
1993 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
1994 FTy, "__tls_init", SourceLocation(),
1996 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2002 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2004 QualType LValType) {
2005 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2009 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2010 llvm::GlobalVariable *GV,
2012 // MSVC only uses guards for static locals.
2013 if (!D.isStaticLocal()) {
2014 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2015 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2016 llvm::Function *F = CGF.CurFn;
2017 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2018 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2019 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2023 // MSVC always uses an i32 bitfield to guard initialization, which is *not*
2024 // threadsafe. Since the user may be linking in inline functions compiled by
2025 // cl.exe, there's no reason to provide a false sense of security by using
2026 // critical sections here.
2029 CGM.ErrorUnsupported(&D, "dynamic TLS initialization");
2031 CGBuilderTy &Builder = CGF.Builder;
2032 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2033 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2035 // Get the guard variable for this function if we have one already.
2036 GuardInfo *GI = &GuardVariableMap[D.getDeclContext()];
2039 if (D.isStaticLocal() && D.isExternallyVisible()) {
2040 // Externally visible variables have to be numbered in Sema to properly
2041 // handle unreachable VarDecls.
2042 BitIndex = getContext().getStaticLocalNumber(&D);
2043 assert(BitIndex > 0);
2046 // Non-externally visible variables are numbered here in CodeGen.
2047 BitIndex = GI->BitIndex++;
2050 if (BitIndex >= 32) {
2051 if (D.isExternallyVisible())
2052 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2054 GI->Guard = nullptr;
2057 // Lazily create the i32 bitfield for this function.
2059 // Mangle the name for the guard.
2060 SmallString<256> GuardName;
2062 llvm::raw_svector_ostream Out(GuardName);
2063 getMangleContext().mangleStaticGuardVariable(&D, Out);
2067 // Create the guard variable with a zero-initializer. Just absorb linkage,
2068 // visibility and dll storage class from the guarded variable.
2070 new llvm::GlobalVariable(CGM.getModule(), GuardTy, false,
2071 GV->getLinkage(), Zero, GuardName.str());
2072 GI->Guard->setVisibility(GV->getVisibility());
2073 GI->Guard->setDLLStorageClass(GV->getDLLStorageClass());
2074 if (GI->Guard->isWeakForLinker())
2075 GI->Guard->setComdat(
2076 CGM.getModule().getOrInsertComdat(GI->Guard->getName()));
2078 assert(GI->Guard->getLinkage() == GV->getLinkage() &&
2079 "static local from the same function had different linkage");
2082 // Pseudo code for the test:
2083 // if (!(GuardVar & MyGuardBit)) {
2084 // GuardVar |= MyGuardBit;
2085 // ... initialize the object ...;
2088 // Test our bit from the guard variable.
2089 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << BitIndex);
2090 llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard);
2091 llvm::Value *IsInitialized =
2092 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2093 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2094 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2095 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2097 // Set our bit in the guard variable and emit the initializer and add a global
2098 // destructor if appropriate.
2099 CGF.EmitBlock(InitBlock);
2100 Builder.CreateStore(Builder.CreateOr(LI, Bit), GI->Guard);
2101 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2102 Builder.CreateBr(EndBlock);
2105 CGF.EmitBlock(EndBlock);
2108 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2109 // Null-ness for function memptrs only depends on the first field, which is
2110 // the function pointer. The rest don't matter, so we can zero initialize.
2111 if (MPT->isMemberFunctionPointer())
2114 // The virtual base adjustment field is always -1 for null, so if we have one
2115 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2116 // valid field offset.
2117 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2118 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2119 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2120 RD->nullFieldOffsetIsZero());
2124 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2125 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2126 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2127 llvm::SmallVector<llvm::Type *, 4> fields;
2128 if (MPT->isMemberFunctionPointer())
2129 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2131 fields.push_back(CGM.IntTy); // FieldOffset
2133 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2135 fields.push_back(CGM.IntTy);
2136 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2137 fields.push_back(CGM.IntTy);
2138 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2139 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2141 if (fields.size() == 1)
2143 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2146 void MicrosoftCXXABI::
2147 GetNullMemberPointerFields(const MemberPointerType *MPT,
2148 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2149 assert(fields.empty());
2150 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2151 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2152 if (MPT->isMemberFunctionPointer()) {
2153 // FunctionPointerOrVirtualThunk
2154 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2156 if (RD->nullFieldOffsetIsZero())
2157 fields.push_back(getZeroInt()); // FieldOffset
2159 fields.push_back(getAllOnesInt()); // FieldOffset
2162 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2164 fields.push_back(getZeroInt());
2165 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2166 fields.push_back(getZeroInt());
2167 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2168 fields.push_back(getAllOnesInt());
2172 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2173 llvm::SmallVector<llvm::Constant *, 4> fields;
2174 GetNullMemberPointerFields(MPT, fields);
2175 if (fields.size() == 1)
2177 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2178 assert(Res->getType() == ConvertMemberPointerType(MPT));
2183 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2184 bool IsMemberFunction,
2185 const CXXRecordDecl *RD,
2186 CharUnits NonVirtualBaseAdjustment)
2188 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2190 // Single inheritance class member pointer are represented as scalars instead
2192 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2195 llvm::SmallVector<llvm::Constant *, 4> fields;
2196 fields.push_back(FirstField);
2198 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2199 fields.push_back(llvm::ConstantInt::get(
2200 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2202 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2203 CharUnits Offs = CharUnits::Zero();
2204 if (RD->getNumVBases())
2205 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2206 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2209 // The rest of the fields are adjusted by conversions to a more derived class.
2210 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2211 fields.push_back(getZeroInt());
2213 return llvm::ConstantStruct::getAnon(fields);
2217 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2219 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2220 llvm::Constant *FirstField =
2221 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2222 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2226 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
2227 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
2230 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2232 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
2233 const ValueDecl *MPD = MP.getMemberPointerDecl();
2235 return EmitNullMemberPointer(MPT);
2237 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
2239 // FIXME PR15713: Support virtual inheritance paths.
2241 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
2242 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
2245 CharUnits FieldOffset =
2246 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
2247 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
2251 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
2252 const CXXMethodDecl *MD,
2253 CharUnits NonVirtualBaseAdjustment) {
2254 assert(MD->isInstance() && "Member function must not be static!");
2255 MD = MD->getCanonicalDecl();
2256 RD = RD->getMostRecentDecl();
2257 CodeGenTypes &Types = CGM.getTypes();
2259 llvm::Constant *FirstField;
2260 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2261 if (!MD->isVirtual()) {
2263 // Check whether the function has a computable LLVM signature.
2264 if (Types.isFuncTypeConvertible(FPT)) {
2265 // The function has a computable LLVM signature; use the correct type.
2266 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2268 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2269 // function type is incomplete.
2272 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2273 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2275 MicrosoftVTableContext::MethodVFTableLocation ML =
2276 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
2277 if (!CGM.getTypes().isFuncTypeConvertible(
2278 MD->getType()->castAs<FunctionType>())) {
2279 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
2280 "incomplete return or parameter type");
2281 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2282 } else if (FPT->getCallConv() == CC_X86FastCall) {
2283 CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
2284 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2285 } else if (ML.VBase) {
2286 CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding "
2287 "member function in virtual base class");
2288 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2290 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2291 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2292 // Include the vfptr adjustment if the method is in a non-primary vftable.
2293 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2297 // The rest of the fields are common with data member pointers.
2298 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2299 NonVirtualBaseAdjustment);
2302 /// Member pointers are the same if they're either bitwise identical *or* both
2303 /// null. Null-ness for function members is determined by the first field,
2304 /// while for data member pointers we must compare all fields.
2306 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2309 const MemberPointerType *MPT,
2311 CGBuilderTy &Builder = CGF.Builder;
2313 // Handle != comparisons by switching the sense of all boolean operations.
2314 llvm::ICmpInst::Predicate Eq;
2315 llvm::Instruction::BinaryOps And, Or;
2317 Eq = llvm::ICmpInst::ICMP_NE;
2318 And = llvm::Instruction::Or;
2319 Or = llvm::Instruction::And;
2321 Eq = llvm::ICmpInst::ICMP_EQ;
2322 And = llvm::Instruction::And;
2323 Or = llvm::Instruction::Or;
2326 // If this is a single field member pointer (single inheritance), this is a
2328 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2329 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2330 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2332 return Builder.CreateICmp(Eq, L, R);
2334 // Compare the first field.
2335 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2336 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2337 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2339 // Compare everything other than the first field.
2340 llvm::Value *Res = nullptr;
2341 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2342 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2343 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2344 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2345 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2347 Res = Builder.CreateBinOp(And, Res, Cmp);
2352 // Check if the first field is 0 if this is a function pointer.
2353 if (MPT->isMemberFunctionPointer()) {
2354 // (l1 == r1 && ...) || l0 == 0
2355 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2356 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2357 Res = Builder.CreateBinOp(Or, Res, IsZero);
2360 // Combine the comparison of the first field, which must always be true for
2361 // this comparison to succeeed.
2362 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2366 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2367 llvm::Value *MemPtr,
2368 const MemberPointerType *MPT) {
2369 CGBuilderTy &Builder = CGF.Builder;
2370 llvm::SmallVector<llvm::Constant *, 4> fields;
2371 // We only need one field for member functions.
2372 if (MPT->isMemberFunctionPointer())
2373 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2375 GetNullMemberPointerFields(MPT, fields);
2376 assert(!fields.empty());
2377 llvm::Value *FirstField = MemPtr;
2378 if (MemPtr->getType()->isStructTy())
2379 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2380 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2382 // For function member pointers, we only need to test the function pointer
2383 // field. The other fields if any can be garbage.
2384 if (MPT->isMemberFunctionPointer())
2387 // Otherwise, emit a series of compares and combine the results.
2388 for (int I = 1, E = fields.size(); I < E; ++I) {
2389 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2390 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2391 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2396 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2397 llvm::Constant *Val) {
2398 // Function pointers are null if the pointer in the first field is null.
2399 if (MPT->isMemberFunctionPointer()) {
2400 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2401 Val->getAggregateElement(0U) : Val;
2402 return FirstField->isNullValue();
2405 // If it's not a function pointer and it's zero initializable, we can easily
2407 if (isZeroInitializable(MPT) && Val->isNullValue())
2410 // Otherwise, break down all the fields for comparison. Hopefully these
2411 // little Constants are reused, while a big null struct might not be.
2412 llvm::SmallVector<llvm::Constant *, 4> Fields;
2413 GetNullMemberPointerFields(MPT, Fields);
2414 if (Fields.size() == 1) {
2415 assert(Val->getType()->isIntegerTy());
2416 return Val == Fields[0];
2420 for (I = 0, E = Fields.size(); I != E; ++I) {
2421 if (Val->getAggregateElement(I) != Fields[I])
2428 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2430 llvm::Value *VBPtrOffset,
2431 llvm::Value *VBTableOffset,
2432 llvm::Value **VBPtrOut) {
2433 CGBuilderTy &Builder = CGF.Builder;
2434 // Load the vbtable pointer from the vbptr in the instance.
2435 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2436 llvm::Value *VBPtr =
2437 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2438 if (VBPtrOut) *VBPtrOut = VBPtr;
2439 VBPtr = Builder.CreateBitCast(VBPtr,
2440 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2441 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2443 // Translate from byte offset to table index. It improves analyzability.
2444 llvm::Value *VBTableIndex = Builder.CreateAShr(
2445 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2446 "vbtindex", /*isExact=*/true);
2448 // Load an i32 offset from the vb-table.
2449 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2450 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2451 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2454 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2456 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2457 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2458 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2459 CGBuilderTy &Builder = CGF.Builder;
2460 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2461 llvm::BasicBlock *OriginalBB = nullptr;
2462 llvm::BasicBlock *SkipAdjustBB = nullptr;
2463 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2465 // In the unspecified inheritance model, there might not be a vbtable at all,
2466 // in which case we need to skip the virtual base lookup. If there is a
2467 // vbtable, the first entry is a no-op entry that gives back the original
2468 // base, so look for a virtual base adjustment offset of zero.
2470 OriginalBB = Builder.GetInsertBlock();
2471 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2472 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2473 llvm::Value *IsVirtual =
2474 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2476 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2477 CGF.EmitBlock(VBaseAdjustBB);
2480 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2481 // know the vbptr offset.
2483 CharUnits offs = CharUnits::Zero();
2484 if (!RD->hasDefinition()) {
2485 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2486 unsigned DiagID = Diags.getCustomDiagID(
2487 DiagnosticsEngine::Error,
2488 "member pointer representation requires a "
2489 "complete class type for %0 to perform this expression");
2490 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2491 } else if (RD->getNumVBases())
2492 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2493 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2495 llvm::Value *VBPtr = nullptr;
2496 llvm::Value *VBaseOffs =
2497 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2498 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2500 // Merge control flow with the case where we didn't have to adjust.
2501 if (VBaseAdjustBB) {
2502 Builder.CreateBr(SkipAdjustBB);
2503 CGF.EmitBlock(SkipAdjustBB);
2504 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2505 Phi->addIncoming(Base, OriginalBB);
2506 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2509 return AdjustedBase;
2512 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2513 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2514 const MemberPointerType *MPT) {
2515 assert(MPT->isMemberDataPointer());
2516 unsigned AS = Base->getType()->getPointerAddressSpace();
2518 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2519 CGBuilderTy &Builder = CGF.Builder;
2520 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2521 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2523 // Extract the fields we need, regardless of model. We'll apply them if we
2525 llvm::Value *FieldOffset = MemPtr;
2526 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2527 llvm::Value *VBPtrOffset = nullptr;
2528 if (MemPtr->getType()->isStructTy()) {
2529 // We need to extract values.
2531 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2532 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2533 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2534 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2535 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2538 if (VirtualBaseAdjustmentOffset) {
2539 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2544 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2546 // Apply the offset, which we assume is non-null.
2548 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2550 // Cast the address to the appropriate pointer type, adopting the address
2551 // space of the base pointer.
2552 return Builder.CreateBitCast(Addr, PType);
2555 static MSInheritanceAttr::Spelling
2556 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2557 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2561 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2564 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2565 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2566 E->getCastKind() == CK_ReinterpretMemberPointer);
2568 // Use constant emission if we can.
2569 if (isa<llvm::Constant>(Src))
2570 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2572 // We may be adding or dropping fields from the member pointer, so we need
2573 // both types and the inheritance models of both records.
2574 const MemberPointerType *SrcTy =
2575 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2576 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2577 bool IsFunc = SrcTy->isMemberFunctionPointer();
2579 // If the classes use the same null representation, reinterpret_cast is a nop.
2580 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2581 if (IsReinterpret && IsFunc)
2584 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2585 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2586 if (IsReinterpret &&
2587 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2590 CGBuilderTy &Builder = CGF.Builder;
2592 // Branch past the conversion if Src is null.
2593 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2594 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2596 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2597 // pointer value of the destination type.
2598 if (IsReinterpret) {
2599 // For reinterpret casts, sema ensures that src and dst are both functions
2600 // or data and have the same size, which means the LLVM types should match.
2601 assert(Src->getType() == DstNull->getType());
2602 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2605 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2606 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2607 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2608 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2609 CGF.EmitBlock(ConvertBB);
2612 llvm::Value *FirstField = Src;
2613 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2614 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2615 llvm::Value *VBPtrOffset = nullptr;
2616 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2617 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2618 // We need to extract values.
2620 FirstField = Builder.CreateExtractValue(Src, I++);
2621 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2622 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2623 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2624 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2625 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2626 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2629 // For data pointers, we adjust the field offset directly. For functions, we
2630 // have a separate field.
2631 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2633 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2634 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2635 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2636 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2637 NVAdjustField = getZeroInt();
2638 if (isDerivedToBase)
2639 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2641 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2644 // FIXME PR15713: Support conversions through virtually derived classes.
2646 // Recompose dst from the null struct and the adjusted fields from src.
2647 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2649 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2652 Dst = llvm::UndefValue::get(DstNull->getType());
2654 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2655 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2656 Dst = Builder.CreateInsertValue(
2657 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2658 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2659 Dst = Builder.CreateInsertValue(
2660 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2661 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2662 Dst = Builder.CreateInsertValue(
2663 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2665 Builder.CreateBr(ContinueBB);
2667 // In the continuation, choose between DstNull and Dst.
2668 CGF.EmitBlock(ContinueBB);
2669 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2670 Phi->addIncoming(DstNull, OriginalBB);
2671 Phi->addIncoming(Dst, ConvertBB);
2676 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2677 llvm::Constant *Src) {
2678 const MemberPointerType *SrcTy =
2679 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2680 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2682 // If src is null, emit a new null for dst. We can't return src because dst
2683 // might have a new representation.
2684 if (MemberPointerConstantIsNull(SrcTy, Src))
2685 return EmitNullMemberPointer(DstTy);
2687 // We don't need to do anything for reinterpret_casts of non-null member
2688 // pointers. We should only get here when the two type representations have
2690 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2693 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2694 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2697 llvm::Constant *FirstField = Src;
2698 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2699 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2700 llvm::Constant *VBPtrOffset = nullptr;
2701 bool IsFunc = SrcTy->isMemberFunctionPointer();
2702 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2703 // We need to extract values.
2705 FirstField = Src->getAggregateElement(I++);
2706 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2707 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2708 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2709 VBPtrOffset = Src->getAggregateElement(I++);
2710 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2711 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2714 // For data pointers, we adjust the field offset directly. For functions, we
2715 // have a separate field.
2716 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2718 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2719 llvm::Constant *&NVAdjustField =
2720 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2721 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2722 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2723 NVAdjustField = getZeroInt();
2724 if (IsDerivedToBase)
2725 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2727 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2730 // FIXME PR15713: Support conversions through virtually derived classes.
2732 // Recompose dst from the null struct and the adjusted fields from src.
2733 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2736 llvm::SmallVector<llvm::Constant *, 4> Fields;
2737 Fields.push_back(FirstField);
2738 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2739 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2740 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2741 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2742 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2743 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2744 return llvm::ConstantStruct::getAnon(Fields);
2747 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2748 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2749 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2750 assert(MPT->isMemberFunctionPointer());
2751 const FunctionProtoType *FPT =
2752 MPT->getPointeeType()->castAs<FunctionProtoType>();
2753 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2754 llvm::FunctionType *FTy =
2755 CGM.getTypes().GetFunctionType(
2756 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2757 CGBuilderTy &Builder = CGF.Builder;
2759 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2761 // Extract the fields we need, regardless of model. We'll apply them if we
2763 llvm::Value *FunctionPointer = MemPtr;
2764 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2765 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2766 llvm::Value *VBPtrOffset = nullptr;
2767 if (MemPtr->getType()->isStructTy()) {
2768 // We need to extract values.
2770 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2771 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2772 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2773 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2774 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2775 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2776 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2779 if (VirtualBaseAdjustmentOffset) {
2780 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2784 if (NonVirtualBaseAdjustment) {
2785 // Apply the adjustment and cast back to the original struct type.
2786 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2787 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2788 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2791 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2794 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2795 return new MicrosoftCXXABI(CGM);
2798 // MS RTTI Overview:
2799 // The run time type information emitted by cl.exe contains 5 distinct types of
2800 // structures. Many of them reference each other.
2802 // TypeInfo: Static classes that are returned by typeid.
2804 // CompleteObjectLocator: Referenced by vftables. They contain information
2805 // required for dynamic casting, including OffsetFromTop. They also contain
2806 // a reference to the TypeInfo for the type and a reference to the
2807 // CompleteHierarchyDescriptor for the type.
2809 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2810 // Used during dynamic_cast to walk a class hierarchy. References a base
2811 // class array and the size of said array.
2813 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2814 // somewhat of a misnomer because the most derived class is also in the list
2815 // as well as multiple copies of virtual bases (if they occur multiple times
2816 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2817 // every path in the hierarchy, in pre-order depth first order. Note, we do
2818 // not declare a specific llvm type for BaseClassArray, it's merely an array
2819 // of BaseClassDescriptor pointers.
2821 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2822 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2823 // BaseClassArray is. It contains information about a class within a
2824 // hierarchy such as: is this base is ambiguous and what is its offset in the
2825 // vbtable. The names of the BaseClassDescriptors have all of their fields
2826 // mangled into them so they can be aggressively deduplicated by the linker.
2828 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2829 StringRef MangledName("\01??_7type_info@@6B@");
2830 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2832 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2834 llvm::GlobalVariable::ExternalLinkage,
2835 /*Initializer=*/nullptr, MangledName);
2840 /// \brief A Helper struct that stores information about a class in a class
2841 /// hierarchy. The information stored in these structs struct is used during
2842 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2843 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2844 // implicit depth first pre-order tree connectivity. getFirstChild and
2845 // getNextSibling allow us to walk the tree efficiently.
2846 struct MSRTTIClass {
2848 IsPrivateOnPath = 1 | 8,
2852 HasHierarchyDescriptor = 64
2854 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
2855 uint32_t initialize(const MSRTTIClass *Parent,
2856 const CXXBaseSpecifier *Specifier);
2858 MSRTTIClass *getFirstChild() { return this + 1; }
2859 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
2860 return Child + 1 + Child->NumBases;
2863 const CXXRecordDecl *RD, *VirtualRoot;
2864 uint32_t Flags, NumBases, OffsetInVBase;
2867 /// \brief Recursively initialize the base class array.
2868 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
2869 const CXXBaseSpecifier *Specifier) {
2870 Flags = HasHierarchyDescriptor;
2872 VirtualRoot = nullptr;
2875 if (Specifier->getAccessSpecifier() != AS_public)
2876 Flags |= IsPrivate | IsPrivateOnPath;
2877 if (Specifier->isVirtual()) {
2882 if (Parent->Flags & IsPrivateOnPath)
2883 Flags |= IsPrivateOnPath;
2884 VirtualRoot = Parent->VirtualRoot;
2885 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
2886 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
2890 MSRTTIClass *Child = getFirstChild();
2891 for (const CXXBaseSpecifier &Base : RD->bases()) {
2892 NumBases += Child->initialize(this, &Base) + 1;
2893 Child = getNextChild(Child);
2898 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
2899 switch (Ty->getLinkage()) {
2901 case InternalLinkage:
2902 case UniqueExternalLinkage:
2903 return llvm::GlobalValue::InternalLinkage;
2905 case VisibleNoLinkage:
2906 case ExternalLinkage:
2907 return llvm::GlobalValue::LinkOnceODRLinkage;
2909 llvm_unreachable("Invalid linkage!");
2912 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
2913 /// calls to the module and information about the most derived class in a
2915 struct MSRTTIBuilder {
2917 HasBranchingHierarchy = 1,
2918 HasVirtualBranchingHierarchy = 2,
2919 HasAmbiguousBases = 4
2922 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
2923 : CGM(ABI.CGM), Context(CGM.getContext()),
2924 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
2925 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
2928 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
2929 llvm::GlobalVariable *
2930 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
2931 llvm::GlobalVariable *getClassHierarchyDescriptor();
2932 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
2935 ASTContext &Context;
2936 llvm::LLVMContext &VMContext;
2937 llvm::Module &Module;
2938 const CXXRecordDecl *RD;
2939 llvm::GlobalVariable::LinkageTypes Linkage;
2940 MicrosoftCXXABI &ABI;
2945 /// \brief Recursively serializes a class hierarchy in pre-order depth first
2947 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
2948 const CXXRecordDecl *RD) {
2949 Classes.push_back(MSRTTIClass(RD));
2950 for (const CXXBaseSpecifier &Base : RD->bases())
2951 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
2954 /// \brief Find ambiguity among base classes.
2956 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
2957 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
2958 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
2959 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
2960 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
2961 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
2962 !VirtualBases.insert(Class->RD).second) {
2963 Class = MSRTTIClass::getNextChild(Class);
2966 if (!UniqueBases.insert(Class->RD).second)
2967 AmbiguousBases.insert(Class->RD);
2970 if (AmbiguousBases.empty())
2972 for (MSRTTIClass &Class : Classes)
2973 if (AmbiguousBases.count(Class.RD))
2974 Class.Flags |= MSRTTIClass::IsAmbiguous;
2977 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
2978 SmallString<256> MangledName;
2980 llvm::raw_svector_ostream Out(MangledName);
2981 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
2984 // Check to see if we've already declared this ClassHierarchyDescriptor.
2985 if (auto CHD = Module.getNamedGlobal(MangledName))
2988 // Serialize the class hierarchy and initialize the CHD Fields.
2989 SmallVector<MSRTTIClass, 8> Classes;
2990 serializeClassHierarchy(Classes, RD);
2991 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
2992 detectAmbiguousBases(Classes);
2994 for (auto Class : Classes) {
2995 if (Class.RD->getNumBases() > 1)
2996 Flags |= HasBranchingHierarchy;
2997 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
2998 // believe the field isn't actually used.
2999 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3000 Flags |= HasAmbiguousBases;
3002 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3003 Flags |= HasVirtualBranchingHierarchy;
3004 // These gep indices are used to get the address of the first element of the
3005 // base class array.
3006 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3007 llvm::ConstantInt::get(CGM.IntTy, 0)};
3009 // Forward-declare the class hierarchy descriptor
3010 auto Type = ABI.getClassHierarchyDescriptorType();
3011 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3012 /*Initializer=*/nullptr,
3013 StringRef(MangledName));
3014 if (CHD->isWeakForLinker())
3015 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3017 // Initialize the base class ClassHierarchyDescriptor.
3018 llvm::Constant *Fields[] = {
3019 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3020 llvm::ConstantInt::get(CGM.IntTy, Flags),
3021 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3022 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3023 getBaseClassArray(Classes),
3024 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3026 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3030 llvm::GlobalVariable *
3031 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3032 SmallString<256> MangledName;
3034 llvm::raw_svector_ostream Out(MangledName);
3035 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3038 // Forward-declare the base class array.
3039 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3040 // mode) bytes of padding. We provide a pointer sized amount of padding by
3041 // adding +1 to Classes.size(). The sections have pointer alignment and are
3042 // marked pick-any so it shouldn't matter.
3043 llvm::Type *PtrType = ABI.getImageRelativeType(
3044 ABI.getBaseClassDescriptorType()->getPointerTo());
3045 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3047 new llvm::GlobalVariable(Module, ArrType,
3048 /*Constant=*/true, Linkage,
3049 /*Initializer=*/nullptr, StringRef(MangledName));
3050 if (BCA->isWeakForLinker())
3051 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3053 // Initialize the BaseClassArray.
3054 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3055 for (MSRTTIClass &Class : Classes)
3056 BaseClassArrayData.push_back(
3057 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3058 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3059 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3063 llvm::GlobalVariable *
3064 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3065 // Compute the fields for the BaseClassDescriptor. They are computed up front
3066 // because they are mangled into the name of the object.
3067 uint32_t OffsetInVBTable = 0;
3068 int32_t VBPtrOffset = -1;
3069 if (Class.VirtualRoot) {
3070 auto &VTableContext = CGM.getMicrosoftVTableContext();
3071 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3072 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3075 SmallString<256> MangledName;
3077 llvm::raw_svector_ostream Out(MangledName);
3078 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3079 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3083 // Check to see if we've already declared this object.
3084 if (auto BCD = Module.getNamedGlobal(MangledName))
3087 // Forward-declare the base class descriptor.
3088 auto Type = ABI.getBaseClassDescriptorType();
3090 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3091 /*Initializer=*/nullptr, StringRef(MangledName));
3092 if (BCD->isWeakForLinker())
3093 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3095 // Initialize the BaseClassDescriptor.
3096 llvm::Constant *Fields[] = {
3097 ABI.getImageRelativeConstant(
3098 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3099 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3100 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3101 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3102 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3103 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3104 ABI.getImageRelativeConstant(
3105 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3107 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3111 llvm::GlobalVariable *
3112 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3113 SmallString<256> MangledName;
3115 llvm::raw_svector_ostream Out(MangledName);
3116 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3119 // Check to see if we've already computed this complete object locator.
3120 if (auto COL = Module.getNamedGlobal(MangledName))
3123 // Compute the fields of the complete object locator.
3124 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3125 int VFPtrOffset = 0;
3126 // The offset includes the vtordisp if one exists.
3127 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3128 if (Context.getASTRecordLayout(RD)
3129 .getVBaseOffsetsMap()
3131 ->second.hasVtorDisp())
3132 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3134 // Forward-declare the complete object locator.
3135 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3136 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3137 /*Initializer=*/nullptr, StringRef(MangledName));
3139 // Initialize the CompleteObjectLocator.
3140 llvm::Constant *Fields[] = {
3141 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3142 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3143 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3144 ABI.getImageRelativeConstant(
3145 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3146 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3147 ABI.getImageRelativeConstant(COL),
3149 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3150 if (!ABI.isImageRelative())
3151 FieldsRef = FieldsRef.drop_back();
3152 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3153 if (COL->isWeakForLinker())
3154 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3158 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3159 bool &IsConst, bool &IsVolatile) {
3160 T = Context.getExceptionObjectType(T);
3162 // C++14 [except.handle]p3:
3163 // A handler is a match for an exception object of type E if [...]
3164 // - the handler is of type cv T or const T& where T is a pointer type and
3165 // E is a pointer type that can be converted to T by [...]
3166 // - a qualification conversion
3169 QualType PointeeType = T->getPointeeType();
3170 if (!PointeeType.isNull()) {
3171 IsConst = PointeeType.isConstQualified();
3172 IsVolatile = PointeeType.isVolatileQualified();
3175 // Member pointer types like "const int A::*" are represented by having RTTI
3176 // for "int A::*" and separately storing the const qualifier.
3177 if (const auto *MPTy = T->getAs<MemberPointerType>())
3178 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3181 // Pointer types like "const int * const *" are represented by having RTTI
3182 // for "const int **" and separately storing the const qualifier.
3183 if (T->isPointerType())
3184 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3189 llvm::Constant *MicrosoftCXXABI::getAddrOfCXXCatchDescriptor(QualType Type) {
3190 // TypeDescriptors for exceptions never has qualified pointer types,
3191 // qualifiers are stored seperately in order to support qualification
3193 bool IsConst, IsVolatile;
3194 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3196 return getAddrOfRTTIDescriptor(Type);
3199 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3200 /// llvm::GlobalVariable * because different type descriptors have different
3201 /// types, and need to be abstracted. They are abstracting by casting the
3202 /// address to an Int8PtrTy.
3203 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3204 SmallString<256> MangledName, TypeInfoString;
3206 llvm::raw_svector_ostream Out(MangledName);
3207 getMangleContext().mangleCXXRTTI(Type, Out);
3210 // Check to see if we've already declared this TypeDescriptor.
3211 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3212 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3214 // Compute the fields for the TypeDescriptor.
3216 llvm::raw_svector_ostream Out(TypeInfoString);
3217 getMangleContext().mangleCXXRTTIName(Type, Out);
3220 // Declare and initialize the TypeDescriptor.
3221 llvm::Constant *Fields[] = {
3222 getTypeInfoVTable(CGM), // VFPtr
3223 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3224 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3225 llvm::StructType *TypeDescriptorType =
3226 getTypeDescriptorType(TypeInfoString);
3227 auto *Var = new llvm::GlobalVariable(
3228 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3229 getLinkageForRTTI(Type),
3230 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3231 StringRef(MangledName));
3232 if (Var->isWeakForLinker())
3233 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3234 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3237 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3238 llvm::GlobalVariable *
3239 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3240 const VPtrInfo *Info) {
3241 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3244 static void emitCXXConstructor(CodeGenModule &CGM,
3245 const CXXConstructorDecl *ctor,
3246 StructorType ctorType) {
3247 // There are no constructor variants, always emit the complete destructor.
3248 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3249 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3252 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3253 StructorType dtorType) {
3254 // The complete destructor is equivalent to the base destructor for
3255 // classes with no virtual bases, so try to emit it as an alias.
3256 if (!dtor->getParent()->getNumVBases() &&
3257 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3258 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3259 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3260 if (ProducedAlias) {
3261 if (dtorType == StructorType::Complete)
3263 if (dtor->isVirtual())
3264 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3268 // The base destructor is equivalent to the base destructor of its
3269 // base class if there is exactly one non-virtual base class with a
3270 // non-trivial destructor, there are no fields with a non-trivial
3271 // destructor, and the body of the destructor is trivial.
3272 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3275 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3276 if (Fn->isWeakForLinker())
3277 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3280 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3281 StructorType Type) {
3282 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3283 emitCXXConstructor(CGM, CD, Type);
3286 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3290 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3292 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3294 // Calculate the mangled name.
3295 SmallString<256> ThunkName;
3296 llvm::raw_svector_ostream Out(ThunkName);
3297 getMangleContext().mangleCXXCtor(CD, CT, Out);
3300 // If the thunk has been generated previously, just return it.
3301 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3302 return cast<llvm::Function>(GV);
3304 // Create the llvm::Function.
3305 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3306 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3307 const CXXRecordDecl *RD = CD->getParent();
3308 QualType RecordTy = getContext().getRecordType(RD);
3309 llvm::Function *ThunkFn = llvm::Function::Create(
3310 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3311 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3312 FnInfo.getEffectiveCallingConvention()));
3313 bool IsCopy = CT == Ctor_CopyingClosure;
3316 CodeGenFunction CGF(CGM);
3317 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3319 // Build FunctionArgs.
3320 FunctionArgList FunctionArgs;
3322 // A constructor always starts with a 'this' pointer as its first argument.
3323 buildThisParam(CGF, FunctionArgs);
3325 // Following the 'this' pointer is a reference to the source object that we
3326 // are copying from.
3327 ImplicitParamDecl SrcParam(
3328 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3329 getContext().getLValueReferenceType(RecordTy,
3330 /*SpelledAsLValue=*/true));
3332 FunctionArgs.push_back(&SrcParam);
3334 // Constructors for classes which utilize virtual bases have an additional
3335 // parameter which indicates whether or not it is being delegated to by a more
3336 // derived constructor.
3337 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3338 &getContext().Idents.get("is_most_derived"),
3339 getContext().IntTy);
3340 // Only add the parameter to the list if thie class has virtual bases.
3341 if (RD->getNumVBases() > 0)
3342 FunctionArgs.push_back(&IsMostDerived);
3344 // Start defining the function.
3345 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3346 FunctionArgs, CD->getLocation(), SourceLocation());
3348 llvm::Value *This = getThisValue(CGF);
3350 llvm::Value *SrcVal =
3351 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3356 // Push the this ptr.
3357 Args.add(RValue::get(This), CD->getThisType(getContext()));
3359 // Push the src ptr.
3361 Args.add(RValue::get(SrcVal), SrcParam.getType());
3363 // Add the rest of the default arguments.
3364 std::vector<Stmt *> ArgVec;
3365 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I)
3366 ArgVec.push_back(getContext().getDefaultArgExprForConstructor(CD, I));
3368 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3370 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3371 ConstExprIterator ArgBegin(ArgVec.data()),
3372 ArgEnd(ArgVec.data() + ArgVec.size());
3373 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3375 // Insert any ABI-specific implicit constructor arguments.
3376 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3377 /*ForVirtualBase=*/false,
3378 /*Delegating=*/false, Args);
3380 // Call the destructor with our arguments.
3381 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3382 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3383 Args, CD, Ctor_Complete, ExtraArgs);
3384 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3386 Cleanups.ForceCleanup();
3388 // Emit the ret instruction, remove any temporary instructions created for the
3390 CGF.FinishFunction(SourceLocation());
3395 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3397 int32_t VBPtrOffset,
3399 assert(!T->isReferenceType());
3401 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3402 const CXXConstructorDecl *CD =
3403 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3404 CXXCtorType CT = Ctor_Complete;
3406 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3407 CT = Ctor_CopyingClosure;
3409 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3410 SmallString<256> MangledName;
3412 llvm::raw_svector_ostream Out(MangledName);
3413 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3414 VBPtrOffset, VBIndex, Out);
3416 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3417 return getImageRelativeConstant(GV);
3419 // The TypeDescriptor is used by the runtime to determine if a catch handler
3420 // is appropriate for the exception object.
3421 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3423 // The runtime is responsible for calling the copy constructor if the
3424 // exception is caught by value.
3425 llvm::Constant *CopyCtor;
3427 if (CT == Ctor_CopyingClosure)
3428 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3430 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3432 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3434 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3436 CopyCtor = getImageRelativeConstant(CopyCtor);
3438 bool IsScalar = !RD;
3439 bool HasVirtualBases = false;
3440 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3441 QualType PointeeType = T;
3442 if (T->isPointerType())
3443 PointeeType = T->getPointeeType();
3444 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3445 HasVirtualBases = RD->getNumVBases() > 0;
3446 if (IdentifierInfo *II = RD->getIdentifier())
3447 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3450 // Encode the relevant CatchableType properties into the Flags bitfield.
3451 // FIXME: Figure out how bits 2 or 8 can get set.
3455 if (HasVirtualBases)
3460 llvm::Constant *Fields[] = {
3461 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3462 TD, // TypeDescriptor
3463 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3464 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3465 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3466 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3467 CopyCtor // CopyCtor
3469 llvm::StructType *CTType = getCatchableTypeType();
3470 auto *GV = new llvm::GlobalVariable(
3471 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3472 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3473 GV->setUnnamedAddr(true);
3474 GV->setSection(".xdata");
3475 if (GV->isWeakForLinker())
3476 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3477 return getImageRelativeConstant(GV);
3480 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3481 assert(!T->isReferenceType());
3483 // See if we've already generated a CatchableTypeArray for this type before.
3484 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3488 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3489 // using a SmallSetVector. Duplicates may arise due to virtual bases
3490 // occurring more than once in the hierarchy.
3491 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3493 // C++14 [except.handle]p3:
3494 // A handler is a match for an exception object of type E if [...]
3495 // - the handler is of type cv T or cv T& and T is an unambiguous public
3496 // base class of E, or
3497 // - the handler is of type cv T or const T& where T is a pointer type and
3498 // E is a pointer type that can be converted to T by [...]
3499 // - a standard pointer conversion (4.10) not involving conversions to
3500 // pointers to private or protected or ambiguous classes
3501 const CXXRecordDecl *MostDerivedClass = nullptr;
3502 bool IsPointer = T->isPointerType();
3504 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3506 MostDerivedClass = T->getAsCXXRecordDecl();
3508 // Collect all the unambiguous public bases of the MostDerivedClass.
3509 if (MostDerivedClass) {
3510 const ASTContext &Context = getContext();
3511 const ASTRecordLayout &MostDerivedLayout =
3512 Context.getASTRecordLayout(MostDerivedClass);
3513 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3514 SmallVector<MSRTTIClass, 8> Classes;
3515 serializeClassHierarchy(Classes, MostDerivedClass);
3516 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3517 detectAmbiguousBases(Classes);
3518 for (const MSRTTIClass &Class : Classes) {
3519 // Skip any ambiguous or private bases.
3521 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3523 // Write down how to convert from a derived pointer to a base pointer.
3524 uint32_t OffsetInVBTable = 0;
3525 int32_t VBPtrOffset = -1;
3526 if (Class.VirtualRoot) {
3528 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3529 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3532 // Turn our record back into a pointer if the exception object is a
3534 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3536 RTTITy = Context.getPointerType(RTTITy);
3537 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3538 VBPtrOffset, OffsetInVBTable));
3542 // C++14 [except.handle]p3:
3543 // A handler is a match for an exception object of type E if
3544 // - The handler is of type cv T or cv T& and E and T are the same type
3545 // (ignoring the top-level cv-qualifiers)
3546 CatchableTypes.insert(getCatchableType(T));
3548 // C++14 [except.handle]p3:
3549 // A handler is a match for an exception object of type E if
3550 // - the handler is of type cv T or const T& where T is a pointer type and
3551 // E is a pointer type that can be converted to T by [...]
3552 // - a standard pointer conversion (4.10) not involving conversions to
3553 // pointers to private or protected or ambiguous classes
3555 // All pointers are convertible to pointer-to-void so ensure that it is in the
3556 // CatchableTypeArray.
3558 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3560 // C++14 [except.handle]p3:
3561 // A handler is a match for an exception object of type E if [...]
3562 // - the handler is of type cv T or const T& where T is a pointer or
3563 // pointer to member type and E is std::nullptr_t.
3565 // We cannot possibly list all possible pointer types here, making this
3566 // implementation incompatible with the standard. However, MSVC includes an
3567 // entry for pointer-to-void in this case. Let's do the same.
3568 if (T->isNullPtrType())
3569 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3571 uint32_t NumEntries = CatchableTypes.size();
3572 llvm::Type *CTType =
3573 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3574 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3575 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3576 llvm::Constant *Fields[] = {
3577 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3578 llvm::ConstantArray::get(
3579 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3580 CatchableTypes.end())) // CatchableTypes
3582 SmallString<256> MangledName;
3584 llvm::raw_svector_ostream Out(MangledName);
3585 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3587 CTA = new llvm::GlobalVariable(
3588 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3589 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3590 CTA->setUnnamedAddr(true);
3591 CTA->setSection(".xdata");
3592 if (CTA->isWeakForLinker())
3593 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3597 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3598 bool IsConst, IsVolatile;
3599 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
3601 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3602 // the exception object may be caught as.
3603 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3604 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3605 // This is used as a component of the mangled name which means that we need to
3606 // know what it is in order to see if we have previously generated the
3608 uint32_t NumEntries =
3609 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3610 ->getLimitedValue();
3612 SmallString<256> MangledName;
3614 llvm::raw_svector_ostream Out(MangledName);
3615 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3619 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3621 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3624 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3625 // be at least as CV qualified. Encode this requirement into the Flags
3633 // The cleanup-function (a destructor) must be called when the exception
3634 // object's lifetime ends.
3635 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3636 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3637 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3638 if (!DtorD->isTrivial())
3639 CleanupFn = llvm::ConstantExpr::getBitCast(
3640 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3642 // This is unused as far as we can tell, initialize it to null.
3643 llvm::Constant *ForwardCompat =
3644 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3645 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3646 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3647 llvm::StructType *TIType = getThrowInfoType();
3648 llvm::Constant *Fields[] = {
3649 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3650 getImageRelativeConstant(CleanupFn), // CleanupFn
3651 ForwardCompat, // ForwardCompat
3652 PointerToCatchableTypes // CatchableTypeArray
3654 auto *GV = new llvm::GlobalVariable(
3655 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3656 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3657 GV->setUnnamedAddr(true);
3658 GV->setSection(".xdata");
3659 if (GV->isWeakForLinker())
3660 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3664 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3665 const Expr *SubExpr = E->getSubExpr();
3666 QualType ThrowType = SubExpr->getType();
3667 // The exception object lives on the stack and it's address is passed to the
3668 // runtime function.
3669 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
3670 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
3673 // The so-called ThrowInfo is used to describe how the exception object may be
3675 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
3677 // Call into the runtime to throw the exception.
3678 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
3679 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);