1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr), CatchHandlerTypeType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
88 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override;
90 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
91 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
92 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
94 llvm::Type *StdTypeInfoPtrTy) override;
96 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
97 QualType SrcRecordTy) override;
99 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
100 QualType SrcRecordTy, QualType DestTy,
101 QualType DestRecordTy,
102 llvm::BasicBlock *CastEnd) override;
104 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
105 QualType SrcRecordTy,
106 QualType DestTy) override;
108 bool EmitBadCastCall(CodeGenFunction &CGF) override;
111 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
112 const CXXRecordDecl *ClassDecl,
113 const CXXRecordDecl *BaseClassDecl) override;
116 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
117 const CXXRecordDecl *RD) override;
119 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
120 const CXXRecordDecl *RD) override;
122 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
124 // Background on MSVC destructors
125 // ==============================
127 // Both Itanium and MSVC ABIs have destructor variants. The variant names
128 // roughly correspond in the following way:
130 // Base -> no name, just ~Class
131 // Complete -> vbase destructor
132 // Deleting -> scalar deleting destructor
133 // vector deleting destructor
135 // The base and complete destructors are the same as in Itanium, although the
136 // complete destructor does not accept a VTT parameter when there are virtual
137 // bases. A separate mechanism involving vtordisps is used to ensure that
138 // virtual methods of destroyed subobjects are not called.
140 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
141 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
142 // pointer points to an array. The scalar deleting destructor assumes that
143 // bit 2 is zero, and therefore does not contain a loop.
145 // For virtual destructors, only one entry is reserved in the vftable, and it
146 // always points to the vector deleting destructor. The vector deleting
147 // destructor is the most general, so it can be used to destroy objects in
148 // place, delete single heap objects, or delete arrays.
150 // A TU defining a non-inline destructor is only guaranteed to emit a base
151 // destructor, and all of the other variants are emitted on an as-needed basis
152 // in COMDATs. Because a non-base destructor can be emitted in a TU that
153 // lacks a definition for the destructor, non-base destructors must always
154 // delegate to or alias the base destructor.
156 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
157 SmallVectorImpl<CanQualType> &ArgTys) override;
159 /// Non-base dtors should be emitted as delegating thunks in this ABI.
160 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
161 CXXDtorType DT) const override {
162 return DT != Dtor_Base;
165 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
167 const CXXRecordDecl *
168 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
169 MD = MD->getCanonicalDecl();
170 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
171 MicrosoftVTableContext::MethodVFTableLocation ML =
172 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
173 // The vbases might be ordered differently in the final overrider object
174 // and the complete object, so the "this" argument may sometimes point to
175 // memory that has no particular type (e.g. past the complete object).
176 // In this case, we just use a generic pointer type.
177 // FIXME: might want to have a more precise type in the non-virtual
178 // multiple inheritance case.
179 if (ML.VBase || !ML.VFPtrOffset.isZero())
182 return MD->getParent();
186 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
188 bool VirtualCall) override;
190 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
191 FunctionArgList &Params) override;
193 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
194 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
196 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
198 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
199 const CXXConstructorDecl *D,
200 CXXCtorType Type, bool ForVirtualBase,
202 CallArgList &Args) override;
204 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
205 CXXDtorType Type, bool ForVirtualBase,
206 bool Delegating, llvm::Value *This) override;
208 void emitVTableDefinitions(CodeGenVTables &CGVT,
209 const CXXRecordDecl *RD) override;
211 llvm::Value *getVTableAddressPointInStructor(
212 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
213 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
214 bool &NeedsVirtualOffset) override;
217 getVTableAddressPointForConstExpr(BaseSubobject Base,
218 const CXXRecordDecl *VTableClass) override;
220 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
221 CharUnits VPtrOffset) override;
223 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
225 llvm::Type *Ty) override;
227 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
228 const CXXDestructorDecl *Dtor,
229 CXXDtorType DtorType,
231 const CXXMemberCallExpr *CE) override;
233 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
234 CallArgList &CallArgs) override {
235 assert(GD.getDtorType() == Dtor_Deleting &&
236 "Only deleting destructor thunks are available in this ABI");
237 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
241 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
243 llvm::GlobalVariable *
244 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
245 llvm::GlobalVariable::LinkageTypes Linkage);
247 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
248 llvm::GlobalVariable *GV) const;
250 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
251 GlobalDecl GD, bool ReturnAdjustment) override {
252 // Never dllimport/dllexport thunks.
253 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
256 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
258 if (Linkage == GVA_Internal)
259 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
260 else if (ReturnAdjustment)
261 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
263 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
266 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
267 const ThisAdjustment &TA) override;
269 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
270 const ReturnAdjustment &RA) override;
272 void EmitThreadLocalInitFuncs(
274 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
276 ArrayRef<llvm::Function *> CXXThreadLocalInits,
277 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
279 bool usesThreadWrapperFunction() const override { return false; }
280 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
281 QualType LValType) override;
283 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
284 llvm::GlobalVariable *DeclPtr,
285 bool PerformInit) override;
286 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
287 llvm::Constant *Dtor, llvm::Constant *Addr) override;
289 // ==== Notes on array cookies =========
291 // MSVC seems to only use cookies when the class has a destructor; a
292 // two-argument usual array deallocation function isn't sufficient.
294 // For example, this code prints "100" and "1":
297 // void *operator new[](size_t sz) {
298 // printf("%u\n", sz);
299 // return malloc(sz);
301 // void operator delete[](void *p, size_t sz) {
302 // printf("%u\n", sz);
307 // A *p = new A[100];
310 // Whereas it prints "104" and "104" if you give A a destructor.
312 bool requiresArrayCookie(const CXXDeleteExpr *expr,
313 QualType elementType) override;
314 bool requiresArrayCookie(const CXXNewExpr *expr) override;
315 CharUnits getArrayCookieSizeImpl(QualType type) override;
316 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
318 llvm::Value *NumElements,
319 const CXXNewExpr *expr,
320 QualType ElementType) override;
321 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
322 llvm::Value *allocPtr,
323 CharUnits cookieSize) override;
325 friend struct MSRTTIBuilder;
327 bool isImageRelative() const {
328 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
331 // 5 routines for constructing the llvm types for MS RTTI structs.
332 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
333 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
334 TDTypeName += llvm::utostr(TypeInfoString.size());
335 llvm::StructType *&TypeDescriptorType =
336 TypeDescriptorTypeMap[TypeInfoString.size()];
337 if (TypeDescriptorType)
338 return TypeDescriptorType;
339 llvm::Type *FieldTypes[] = {
342 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
344 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
345 return TypeDescriptorType;
348 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
349 if (!isImageRelative())
354 llvm::StructType *getBaseClassDescriptorType() {
355 if (BaseClassDescriptorType)
356 return BaseClassDescriptorType;
357 llvm::Type *FieldTypes[] = {
358 getImageRelativeType(CGM.Int8PtrTy),
364 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
366 BaseClassDescriptorType = llvm::StructType::create(
367 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
368 return BaseClassDescriptorType;
371 llvm::StructType *getClassHierarchyDescriptorType() {
372 if (ClassHierarchyDescriptorType)
373 return ClassHierarchyDescriptorType;
374 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
375 ClassHierarchyDescriptorType = llvm::StructType::create(
376 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
377 llvm::Type *FieldTypes[] = {
381 getImageRelativeType(
382 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
384 ClassHierarchyDescriptorType->setBody(FieldTypes);
385 return ClassHierarchyDescriptorType;
388 llvm::StructType *getCompleteObjectLocatorType() {
389 if (CompleteObjectLocatorType)
390 return CompleteObjectLocatorType;
391 CompleteObjectLocatorType = llvm::StructType::create(
392 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
393 llvm::Type *FieldTypes[] = {
397 getImageRelativeType(CGM.Int8PtrTy),
398 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
399 getImageRelativeType(CompleteObjectLocatorType),
401 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
402 if (!isImageRelative())
403 FieldTypesRef = FieldTypesRef.drop_back();
404 CompleteObjectLocatorType->setBody(FieldTypesRef);
405 return CompleteObjectLocatorType;
408 llvm::GlobalVariable *getImageBase() {
409 StringRef Name = "__ImageBase";
410 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
413 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
415 llvm::GlobalValue::ExternalLinkage,
416 /*Initializer=*/nullptr, Name);
419 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
420 if (!isImageRelative())
423 if (PtrVal->isNullValue())
424 return llvm::Constant::getNullValue(CGM.IntTy);
426 llvm::Constant *ImageBaseAsInt =
427 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
428 llvm::Constant *PtrValAsInt =
429 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
430 llvm::Constant *Diff =
431 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
432 /*HasNUW=*/true, /*HasNSW=*/true);
433 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
437 MicrosoftMangleContext &getMangleContext() {
438 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
441 llvm::Constant *getZeroInt() {
442 return llvm::ConstantInt::get(CGM.IntTy, 0);
445 llvm::Constant *getAllOnesInt() {
446 return llvm::Constant::getAllOnesValue(CGM.IntTy);
449 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
450 return C ? C : getZeroInt();
453 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
454 return C ? C : getZeroInt();
457 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
460 GetNullMemberPointerFields(const MemberPointerType *MPT,
461 llvm::SmallVectorImpl<llvm::Constant *> &fields);
463 /// \brief Shared code for virtual base adjustment. Returns the offset from
464 /// the vbptr to the virtual base. Optionally returns the address of the
466 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
468 llvm::Value *VBPtrOffset,
469 llvm::Value *VBTableOffset,
470 llvm::Value **VBPtr = nullptr);
472 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
475 int32_t VBTableOffset,
476 llvm::Value **VBPtr = nullptr) {
477 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
478 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
479 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
480 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
483 std::pair<llvm::Value *, llvm::Value *>
484 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
485 QualType SrcRecordTy);
487 /// \brief Performs a full virtual base adjustment. Used to dereference
488 /// pointers to members of virtual bases.
489 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
490 const CXXRecordDecl *RD, llvm::Value *Base,
491 llvm::Value *VirtualBaseAdjustmentOffset,
492 llvm::Value *VBPtrOffset /* optional */);
494 /// \brief Emits a full member pointer with the fields common to data and
495 /// function member pointers.
496 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
497 bool IsMemberFunction,
498 const CXXRecordDecl *RD,
499 CharUnits NonVirtualBaseAdjustment,
500 unsigned VBTableIndex);
502 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
503 const CXXMethodDecl *MD,
504 CharUnits NonVirtualBaseAdjustment);
506 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
509 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
510 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
512 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
513 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
515 /// \brief Generate a thunk for calling a virtual member function MD.
516 llvm::Function *EmitVirtualMemPtrThunk(
517 const CXXMethodDecl *MD,
518 const MicrosoftVTableContext::MethodVFTableLocation &ML);
521 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
523 bool isZeroInitializable(const MemberPointerType *MPT) override;
525 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
526 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
527 return RD->hasAttr<MSInheritanceAttr>();
530 bool isTypeInfoCalculable(QualType Ty) const override {
531 if (!CGCXXABI::isTypeInfoCalculable(Ty))
533 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
534 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
535 if (!RD->hasAttr<MSInheritanceAttr>())
541 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
543 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
544 CharUnits offset) override;
545 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
546 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
548 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
551 const MemberPointerType *MPT,
552 bool Inequality) override;
554 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
556 const MemberPointerType *MPT) override;
559 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
560 llvm::Value *Base, llvm::Value *MemPtr,
561 const MemberPointerType *MPT) override;
563 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
565 llvm::Value *Src) override;
567 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
568 llvm::Constant *Src) override;
571 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
572 llvm::Value *&This, llvm::Value *MemPtr,
573 const MemberPointerType *MPT) override;
575 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
577 llvm::StructType *getCatchHandlerTypeType() {
578 if (!CatchHandlerTypeType) {
579 llvm::Type *FieldTypes[] = {
581 CGM.Int8PtrTy, // TypeDescriptor
583 CatchHandlerTypeType = llvm::StructType::create(
584 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
586 return CatchHandlerTypeType;
589 llvm::StructType *getCatchableTypeType() {
590 if (CatchableTypeType)
591 return CatchableTypeType;
592 llvm::Type *FieldTypes[] = {
594 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
595 CGM.IntTy, // NonVirtualAdjustment
596 CGM.IntTy, // OffsetToVBPtr
597 CGM.IntTy, // VBTableIndex
599 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
601 CatchableTypeType = llvm::StructType::create(
602 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
603 return CatchableTypeType;
606 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
607 llvm::StructType *&CatchableTypeArrayType =
608 CatchableTypeArrayTypeMap[NumEntries];
609 if (CatchableTypeArrayType)
610 return CatchableTypeArrayType;
612 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
613 CTATypeName += llvm::utostr(NumEntries);
615 getImageRelativeType(getCatchableTypeType()->getPointerTo());
616 llvm::Type *FieldTypes[] = {
617 CGM.IntTy, // NumEntries
618 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
620 CatchableTypeArrayType =
621 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
622 return CatchableTypeArrayType;
625 llvm::StructType *getThrowInfoType() {
627 return ThrowInfoType;
628 llvm::Type *FieldTypes[] = {
630 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
631 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
632 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
634 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
636 return ThrowInfoType;
639 llvm::Constant *getThrowFn() {
640 // _CxxThrowException is passed an exception object and a ThrowInfo object
641 // which describes the exception.
642 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
643 llvm::FunctionType *FTy =
644 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
645 auto *Fn = cast<llvm::Function>(
646 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
647 // _CxxThrowException is stdcall on 32-bit x86 platforms.
648 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
649 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
653 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
656 llvm::Constant *getCatchableType(QualType T,
657 uint32_t NVOffset = 0,
658 int32_t VBPtrOffset = -1,
659 uint32_t VBIndex = 0);
661 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
663 llvm::GlobalVariable *getThrowInfo(QualType T) override;
666 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
667 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
668 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
669 /// \brief All the vftables that have been referenced.
670 VFTablesMapTy VFTablesMap;
671 VTablesMapTy VTablesMap;
673 /// \brief This set holds the record decls we've deferred vtable emission for.
674 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
677 /// \brief All the vbtables which have been referenced.
678 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
680 /// Info on the global variable used to guard initialization of static locals.
681 /// The BitIndex field is only used for externally invisible declarations.
683 GuardInfo() : Guard(nullptr), BitIndex(0) {}
684 llvm::GlobalVariable *Guard;
688 /// Map from DeclContext to the current guard variable. We assume that the
689 /// AST is visited in source code order.
690 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
691 llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap;
692 llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap;
694 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
695 llvm::StructType *BaseClassDescriptorType;
696 llvm::StructType *ClassHierarchyDescriptorType;
697 llvm::StructType *CompleteObjectLocatorType;
699 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
701 llvm::StructType *CatchableTypeType;
702 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
703 llvm::StructType *ThrowInfoType;
704 llvm::StructType *CatchHandlerTypeType;
709 CGCXXABI::RecordArgABI
710 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
711 switch (CGM.getTarget().getTriple().getArch()) {
713 // FIXME: Implement for other architectures.
716 case llvm::Triple::x86:
717 // All record arguments are passed in memory on x86. Decide whether to
718 // construct the object directly in argument memory, or to construct the
719 // argument elsewhere and copy the bytes during the call.
721 // If C++ prohibits us from making a copy, construct the arguments directly
722 // into argument memory.
723 if (!canCopyArgument(RD))
724 return RAA_DirectInMemory;
726 // Otherwise, construct the argument into a temporary and copy the bytes
727 // into the outgoing argument memory.
730 case llvm::Triple::x86_64:
731 // Win64 passes objects with non-trivial copy ctors indirectly.
732 if (RD->hasNonTrivialCopyConstructor())
735 // If an object has a destructor, we'd really like to pass it indirectly
736 // because it allows us to elide copies. Unfortunately, MSVC makes that
737 // impossible for small types, which it will pass in a single register or
738 // stack slot. Most objects with dtors are large-ish, so handle that early.
739 // We can't call out all large objects as being indirect because there are
740 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
741 // how we pass large POD types.
742 if (RD->hasNonTrivialDestructor() &&
743 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
746 // We have a trivial copy constructor or no copy constructors, but we have
747 // to make sure it isn't deleted.
748 bool CopyDeleted = false;
749 for (const CXXConstructorDecl *CD : RD->ctors()) {
750 if (CD->isCopyConstructor()) {
751 assert(CD->isTrivial());
752 // We had at least one undeleted trivial copy ctor. Return directly.
753 if (!CD->isDeleted())
759 // The trivial copy constructor was deleted. Return indirectly.
763 // There were no copy ctors. Return in RAX.
767 llvm_unreachable("invalid enum");
770 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
771 const CXXDeleteExpr *DE,
773 QualType ElementType,
774 const CXXDestructorDecl *Dtor) {
775 // FIXME: Provide a source location here even though there's no
776 // CXXMemberCallExpr for dtor call.
777 bool UseGlobalDelete = DE->isGlobalDelete();
778 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
779 llvm::Value *MDThis =
780 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
782 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
785 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
786 llvm::Value *Args[] = {
787 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
788 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
789 auto *Fn = getThrowFn();
791 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
793 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
797 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
798 CallEndCatchMSVC() {}
799 void Emit(CodeGenFunction &CGF, Flags flags) override {
800 CGF.EmitNounwindRuntimeCall(
801 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
806 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
807 const CXXCatchStmt *S) {
808 // In the MS ABI, the runtime handles the copy, and the catch handler is
809 // responsible for destruction.
810 VarDecl *CatchParam = S->getExceptionDecl();
811 llvm::Value *Exn = CGF.getExceptionFromSlot();
812 llvm::Function *BeginCatch =
813 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
815 // If this is a catch-all or the catch parameter is unnamed, we don't need to
816 // emit an alloca to the object.
817 if (!CatchParam || !CatchParam->getDeclName()) {
818 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
819 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
820 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
824 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
825 llvm::Value *ParamAddr =
826 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
827 llvm::Value *Args[2] = {Exn, ParamAddr};
828 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
829 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
830 CGF.EmitAutoVarCleanups(var);
833 std::pair<llvm::Value *, llvm::Value *>
834 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
835 QualType SrcRecordTy) {
836 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
837 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
838 const ASTContext &Context = getContext();
840 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
841 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
843 // Perform a base adjustment.
844 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
845 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
846 [&](const CXXBaseSpecifier &Base) {
847 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
848 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
850 llvm::Value *Offset = GetVirtualBaseClassOffset(
851 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
852 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
853 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
854 return std::make_pair(Value, Offset);
857 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
858 QualType SrcRecordTy) {
859 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
861 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
864 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
865 llvm::Value *Argument) {
866 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
867 llvm::FunctionType *FTy =
868 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
869 llvm::Value *Args[] = {Argument};
870 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
871 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
874 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
875 llvm::CallSite Call =
876 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
877 Call.setDoesNotReturn();
878 CGF.Builder.CreateUnreachable();
881 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
882 QualType SrcRecordTy,
883 llvm::Value *ThisPtr,
884 llvm::Type *StdTypeInfoPtrTy) {
886 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
887 return CGF.Builder.CreateBitCast(
888 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
891 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
892 QualType SrcRecordTy) {
893 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
895 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
898 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
899 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
900 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
901 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
903 llvm::Value *SrcRTTI =
904 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
905 llvm::Value *DestRTTI =
906 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
909 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
911 // PVOID __RTDynamicCast(
917 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
918 CGF.Int8PtrTy, CGF.Int32Ty};
919 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
920 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
922 llvm::Value *Args[] = {
923 Value, Offset, SrcRTTI, DestRTTI,
924 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
925 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
926 return CGF.Builder.CreateBitCast(Value, DestLTy);
930 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
931 QualType SrcRecordTy,
934 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
936 // PVOID __RTCastToVoid(
938 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
939 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
940 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
942 llvm::Value *Args[] = {Value};
943 return CGF.EmitRuntimeCall(Function, Args);
946 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
950 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
951 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
952 const CXXRecordDecl *BaseClassDecl) {
953 const ASTContext &Context = getContext();
955 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
956 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
957 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
958 CharUnits VBTableChars =
960 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
961 llvm::Value *VBTableOffset =
962 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
964 llvm::Value *VBPtrToNewBase =
965 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
967 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
968 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
971 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
972 return isa<CXXConstructorDecl>(GD.getDecl());
975 static bool isDeletingDtor(GlobalDecl GD) {
976 return isa<CXXDestructorDecl>(GD.getDecl()) &&
977 GD.getDtorType() == Dtor_Deleting;
980 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
981 return isDeletingDtor(GD);
984 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
985 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
989 if (FI.isInstanceMethod()) {
990 // If it's an instance method, aggregates are always returned indirectly via
991 // the second parameter.
992 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
993 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
995 } else if (!RD->isPOD()) {
996 // If it's a free function, non-POD types are returned indirectly.
997 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
1001 // Otherwise, use the C ABI rules.
1006 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1007 const CXXRecordDecl *RD) {
1008 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1009 assert(IsMostDerivedClass &&
1010 "ctor for a class with virtual bases must have an implicit parameter");
1011 llvm::Value *IsCompleteObject =
1012 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1014 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1015 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1016 CGF.Builder.CreateCondBr(IsCompleteObject,
1017 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1019 CGF.EmitBlock(CallVbaseCtorsBB);
1021 // Fill in the vbtable pointers here.
1022 EmitVBPtrStores(CGF, RD);
1024 // CGF will put the base ctor calls in this basic block for us later.
1026 return SkipVbaseCtorsBB;
1029 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1030 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1031 // In most cases, an override for a vbase virtual method can adjust
1032 // the "this" parameter by applying a constant offset.
1033 // However, this is not enough while a constructor or a destructor of some
1034 // class X is being executed if all the following conditions are met:
1035 // - X has virtual bases, (1)
1036 // - X overrides a virtual method M of a vbase Y, (2)
1037 // - X itself is a vbase of the most derived class.
1039 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1040 // which holds the extra amount of "this" adjustment we must do when we use
1041 // the X vftables (i.e. during X ctor or dtor).
1042 // Outside the ctors and dtors, the values of vtorDisps are zero.
1044 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1045 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1046 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1047 CGBuilderTy &Builder = CGF.Builder;
1050 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1051 llvm::Value *Int8This = nullptr; // Initialize lazily.
1053 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1055 if (!I->second.hasVtorDisp())
1058 llvm::Value *VBaseOffset =
1059 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1060 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1061 // just to Trunc back immediately.
1062 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1063 uint64_t ConstantVBaseOffset =
1064 Layout.getVBaseClassOffset(I->first).getQuantity();
1066 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1067 llvm::Value *VtorDispValue = Builder.CreateSub(
1068 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1072 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1073 CGF.Int8Ty->getPointerTo(AS));
1074 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1075 // vtorDisp is always the 32-bits before the vbase in the class layout.
1076 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1077 VtorDispPtr = Builder.CreateBitCast(
1078 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1080 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1084 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1085 const CXXMethodDecl *MD) {
1086 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1087 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1088 CallingConv ActualCallingConv =
1089 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1090 return ExpectedCallingConv == ActualCallingConv;
1093 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1094 // There's only one constructor type in this ABI.
1095 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1097 // Exported default constructors either have a simple call-site where they use
1098 // the typical calling convention and have a single 'this' pointer for an
1099 // argument -or- they get a wrapper function which appropriately thunks to the
1100 // real default constructor. This thunk is the default constructor closure.
1101 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1102 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1103 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1104 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1105 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1109 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1110 const CXXRecordDecl *RD) {
1111 llvm::Value *ThisInt8Ptr =
1112 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1113 const ASTContext &Context = getContext();
1114 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1116 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1117 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1118 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1119 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1120 const ASTRecordLayout &SubobjectLayout =
1121 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1122 CharUnits Offs = VBT->NonVirtualOffset;
1123 Offs += SubobjectLayout.getVBPtrOffset();
1124 if (VBT->getVBaseWithVPtr())
1125 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1126 llvm::Value *VBPtr =
1127 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1128 llvm::Value *GVPtr =
1129 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1130 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1131 "vbptr." + VBT->ReusingBase->getName());
1132 CGF.Builder.CreateStore(GVPtr, VBPtr);
1137 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1138 SmallVectorImpl<CanQualType> &ArgTys) {
1139 // TODO: 'for base' flag
1140 if (T == StructorType::Deleting) {
1141 // The scalar deleting destructor takes an implicit int parameter.
1142 ArgTys.push_back(getContext().IntTy);
1144 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1148 // All parameters are already in place except is_most_derived, which goes
1149 // after 'this' if it's variadic and last if it's not.
1151 const CXXRecordDecl *Class = CD->getParent();
1152 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1153 if (Class->getNumVBases()) {
1154 if (FPT->isVariadic())
1155 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1157 ArgTys.push_back(getContext().IntTy);
1161 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1162 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1163 // other destructor variants are delegating thunks.
1164 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1168 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1169 GD = GD.getCanonicalDecl();
1170 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1172 GlobalDecl LookupGD = GD;
1173 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1174 // Complete destructors take a pointer to the complete object as a
1175 // parameter, thus don't need this adjustment.
1176 if (GD.getDtorType() == Dtor_Complete)
1179 // There's no Dtor_Base in vftable but it shares the this adjustment with
1180 // the deleting one, so look it up instead.
1181 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1184 MicrosoftVTableContext::MethodVFTableLocation ML =
1185 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1186 CharUnits Adjustment = ML.VFPtrOffset;
1188 // Normal virtual instance methods need to adjust from the vfptr that first
1189 // defined the virtual method to the virtual base subobject, but destructors
1190 // do not. The vector deleting destructor thunk applies this adjustment for
1192 if (isa<CXXDestructorDecl>(MD))
1193 Adjustment = CharUnits::Zero();
1196 const ASTRecordLayout &DerivedLayout =
1197 getContext().getASTRecordLayout(MD->getParent());
1198 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1204 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1205 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1207 // If the call of a virtual function is not virtual, we just have to
1208 // compensate for the adjustment the virtual function does in its prologue.
1209 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1210 if (Adjustment.isZero())
1213 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1214 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1215 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1216 assert(Adjustment.isPositive());
1217 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1220 GD = GD.getCanonicalDecl();
1221 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1223 GlobalDecl LookupGD = GD;
1224 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1225 // Complete dtors take a pointer to the complete object,
1226 // thus don't need adjustment.
1227 if (GD.getDtorType() == Dtor_Complete)
1230 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1231 // with the base one, so look up the deleting one instead.
1232 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1234 MicrosoftVTableContext::MethodVFTableLocation ML =
1235 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1237 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1238 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1239 CharUnits StaticOffset = ML.VFPtrOffset;
1241 // Base destructors expect 'this' to point to the beginning of the base
1242 // subobject, not the first vfptr that happens to contain the virtual dtor.
1243 // However, we still need to apply the virtual base adjustment.
1244 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1245 StaticOffset = CharUnits::Zero();
1248 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1249 llvm::Value *VBaseOffset =
1250 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1251 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1253 if (!StaticOffset.isZero()) {
1254 assert(StaticOffset.isPositive());
1255 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1257 // Non-virtual adjustment might result in a pointer outside the allocated
1258 // object, e.g. if the final overrider class is laid out after the virtual
1259 // base that declares a method in the most derived class.
1260 // FIXME: Update the code that emits this adjustment in thunks prologues.
1261 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1263 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1264 StaticOffset.getQuantity());
1270 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1272 FunctionArgList &Params) {
1273 ASTContext &Context = getContext();
1274 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1275 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1276 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1277 ImplicitParamDecl *IsMostDerived
1278 = ImplicitParamDecl::Create(Context, nullptr,
1279 CGF.CurGD.getDecl()->getLocation(),
1280 &Context.Idents.get("is_most_derived"),
1282 // The 'most_derived' parameter goes second if the ctor is variadic and last
1283 // if it's not. Dtors can't be variadic.
1284 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1285 if (FPT->isVariadic())
1286 Params.insert(Params.begin() + 1, IsMostDerived);
1288 Params.push_back(IsMostDerived);
1289 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1290 } else if (isDeletingDtor(CGF.CurGD)) {
1291 ImplicitParamDecl *ShouldDelete
1292 = ImplicitParamDecl::Create(Context, nullptr,
1293 CGF.CurGD.getDecl()->getLocation(),
1294 &Context.Idents.get("should_call_delete"),
1296 Params.push_back(ShouldDelete);
1297 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1301 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1302 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1303 // In this ABI, every virtual function takes a pointer to one of the
1304 // subobjects that first defines it as the 'this' parameter, rather than a
1305 // pointer to the final overrider subobject. Thus, we need to adjust it back
1306 // to the final overrider subobject before use.
1307 // See comments in the MicrosoftVFTableContext implementation for the details.
1308 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1309 if (Adjustment.isZero())
1312 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1313 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1314 *thisTy = This->getType();
1316 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1317 assert(Adjustment.isPositive());
1318 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1319 -Adjustment.getQuantity());
1320 return CGF.Builder.CreateBitCast(This, thisTy);
1323 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1326 /// If this is a function that the ABI specifies returns 'this', initialize
1327 /// the return slot to 'this' at the start of the function.
1329 /// Unlike the setting of return types, this is done within the ABI
1330 /// implementation instead of by clients of CGCXXABI because:
1331 /// 1) getThisValue is currently protected
1332 /// 2) in theory, an ABI could implement 'this' returns some other way;
1333 /// HasThisReturn only specifies a contract, not the implementation
1334 if (HasThisReturn(CGF.CurGD))
1335 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1336 else if (hasMostDerivedReturn(CGF.CurGD))
1337 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1340 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1341 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1342 assert(getStructorImplicitParamDecl(CGF) &&
1343 "no implicit parameter for a constructor with virtual bases?");
1344 getStructorImplicitParamValue(CGF)
1345 = CGF.Builder.CreateLoad(
1346 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1350 if (isDeletingDtor(CGF.CurGD)) {
1351 assert(getStructorImplicitParamDecl(CGF) &&
1352 "no implicit parameter for a deleting destructor?");
1353 getStructorImplicitParamValue(CGF)
1354 = CGF.Builder.CreateLoad(
1355 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1356 "should_call_delete");
1360 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1361 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1362 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1363 assert(Type == Ctor_Complete || Type == Ctor_Base);
1365 // Check if we need a 'most_derived' parameter.
1366 if (!D->getParent()->getNumVBases())
1369 // Add the 'most_derived' argument second if we are variadic or last if not.
1370 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1371 llvm::Value *MostDerivedArg =
1372 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1373 RValue RV = RValue::get(MostDerivedArg);
1374 if (MostDerivedArg) {
1375 if (FPT->isVariadic())
1376 Args.insert(Args.begin() + 1,
1377 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1379 Args.add(RV, getContext().IntTy);
1382 return 1; // Added one arg.
1385 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1386 const CXXDestructorDecl *DD,
1387 CXXDtorType Type, bool ForVirtualBase,
1388 bool Delegating, llvm::Value *This) {
1389 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1391 if (DD->isVirtual()) {
1392 assert(Type != CXXDtorType::Dtor_Deleting &&
1393 "The deleting destructor should only be called via a virtual call");
1394 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1398 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1399 /*ImplicitParam=*/nullptr,
1400 /*ImplicitParamTy=*/QualType(), nullptr,
1401 getFromDtorType(Type));
1404 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1405 const CXXRecordDecl *RD) {
1406 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1407 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1409 for (VPtrInfo *Info : VFPtrs) {
1410 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1411 if (VTable->hasInitializer())
1414 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1415 ? getMSCompleteObjectLocator(RD, Info)
1418 const VTableLayout &VTLayout =
1419 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1420 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1421 RD, VTLayout.vtable_component_begin(),
1422 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1423 VTLayout.getNumVTableThunks(), RTTI);
1425 VTable->setInitializer(Init);
1429 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1430 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1431 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1432 NeedsVirtualOffset = (NearestVBase != nullptr);
1434 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1435 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1436 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1437 if (!VTableAddressPoint) {
1438 assert(Base.getBase()->getNumVBases() &&
1439 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1441 return VTableAddressPoint;
1444 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1445 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1446 SmallString<256> &Name) {
1447 llvm::raw_svector_ostream Out(Name);
1448 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1451 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1452 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1453 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1454 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1455 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1456 assert(VFTable && "Couldn't find a vftable for the given base?");
1460 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1461 CharUnits VPtrOffset) {
1462 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1463 // shouldn't be used in the given record type. We want to cache this result in
1464 // VFTablesMap, thus a simple zero check is not sufficient.
1465 VFTableIdTy ID(RD, VPtrOffset);
1466 VTablesMapTy::iterator I;
1468 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1472 llvm::GlobalVariable *&VTable = I->second;
1474 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1475 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1477 if (DeferredVFTables.insert(RD).second) {
1478 // We haven't processed this record type before.
1479 // Queue up this v-table for possible deferred emission.
1480 CGM.addDeferredVTable(RD);
1483 // Create all the vftables at once in order to make sure each vftable has
1484 // a unique mangled name.
1485 llvm::StringSet<> ObservedMangledNames;
1486 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1487 SmallString<256> Name;
1488 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1489 if (!ObservedMangledNames.insert(Name.str()).second)
1490 llvm_unreachable("Already saw this mangling before?");
1495 VPtrInfo *const *VFPtrI =
1496 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1497 return VPI->FullOffsetInMDC == VPtrOffset;
1499 if (VFPtrI == VFPtrs.end()) {
1500 VFTablesMap[ID] = nullptr;
1503 VPtrInfo *VFPtr = *VFPtrI;
1505 SmallString<256> VFTableName;
1506 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1508 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1509 bool VFTableComesFromAnotherTU =
1510 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1511 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1512 bool VTableAliasIsRequred =
1513 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1515 if (llvm::GlobalValue *VFTable =
1516 CGM.getModule().getNamedGlobal(VFTableName)) {
1517 VFTablesMap[ID] = VFTable;
1518 return VTableAliasIsRequred
1519 ? cast<llvm::GlobalVariable>(
1520 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1521 : cast<llvm::GlobalVariable>(VFTable);
1524 uint64_t NumVTableSlots =
1525 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1526 .getNumVTableComponents();
1527 llvm::GlobalValue::LinkageTypes VTableLinkage =
1528 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1530 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1532 llvm::ArrayType *VTableType =
1533 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1535 // Create a backing variable for the contents of VTable. The VTable may
1536 // or may not include space for a pointer to RTTI data.
1537 llvm::GlobalValue *VFTable;
1538 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1539 /*isConstant=*/true, VTableLinkage,
1540 /*Initializer=*/nullptr, VTableName);
1541 VTable->setUnnamedAddr(true);
1543 llvm::Comdat *C = nullptr;
1544 if (!VFTableComesFromAnotherTU &&
1545 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1546 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1547 VTableAliasIsRequred)))
1548 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1550 // Only insert a pointer into the VFTable for RTTI data if we are not
1551 // importing it. We never reference the RTTI data directly so there is no
1552 // need to make room for it.
1553 if (VTableAliasIsRequred) {
1554 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1555 llvm::ConstantInt::get(CGM.IntTy, 1)};
1556 // Create a GEP which points just after the first entry in the VFTable,
1557 // this should be the location of the first virtual method.
1558 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1559 VTable->getValueType(), VTable, GEPIndices);
1560 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1561 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1563 C->setSelectionKind(llvm::Comdat::Largest);
1565 VFTable = llvm::GlobalAlias::create(
1566 cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage,
1567 VFTableName.str(), VTableGEP, &CGM.getModule());
1568 VFTable->setUnnamedAddr(true);
1570 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1571 // be referencing any RTTI data.
1572 // The GlobalVariable will end up being an appropriate definition of the
1577 VTable->setComdat(C);
1579 if (RD->hasAttr<DLLImportAttr>())
1580 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1581 else if (RD->hasAttr<DLLExportAttr>())
1582 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1584 VFTablesMap[ID] = VFTable;
1588 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1592 GD = GD.getCanonicalDecl();
1593 CGBuilderTy &Builder = CGF.Builder;
1595 Ty = Ty->getPointerTo()->getPointerTo();
1597 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1598 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1600 MicrosoftVTableContext::MethodVFTableLocation ML =
1601 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1602 llvm::Value *VFuncPtr =
1603 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1604 return Builder.CreateLoad(VFuncPtr);
1607 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1608 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1609 llvm::Value *This, const CXXMemberCallExpr *CE) {
1610 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1611 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1613 // We have only one destructor in the vftable but can get both behaviors
1614 // by passing an implicit int parameter.
1615 GlobalDecl GD(Dtor, Dtor_Deleting);
1616 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1617 Dtor, StructorType::Deleting);
1618 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1619 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1621 ASTContext &Context = getContext();
1622 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1623 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1624 DtorType == Dtor_Deleting);
1626 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1627 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1628 ImplicitParam, Context.IntTy, CE,
1629 StructorType::Deleting);
1630 return RV.getScalarVal();
1633 const VBTableGlobals &
1634 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1635 // At this layer, we can key the cache off of a single class, which is much
1636 // easier than caching each vbtable individually.
1637 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1639 std::tie(Entry, Added) =
1640 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1641 VBTableGlobals &VBGlobals = Entry->second;
1645 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1646 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1648 // Cache the globals for all vbtables so we don't have to recompute the
1650 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1651 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1652 E = VBGlobals.VBTables->end();
1654 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1660 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1661 const CXXMethodDecl *MD,
1662 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1663 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1664 "can't form pointers to ctors or virtual dtors");
1666 // Calculate the mangled name.
1667 SmallString<256> ThunkName;
1668 llvm::raw_svector_ostream Out(ThunkName);
1669 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1672 // If the thunk has been generated previously, just return it.
1673 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1674 return cast<llvm::Function>(GV);
1676 // Create the llvm::Function.
1677 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1678 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1679 llvm::Function *ThunkFn =
1680 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1681 ThunkName.str(), &CGM.getModule());
1682 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1684 ThunkFn->setLinkage(MD->isExternallyVisible()
1685 ? llvm::GlobalValue::LinkOnceODRLinkage
1686 : llvm::GlobalValue::InternalLinkage);
1687 if (MD->isExternallyVisible())
1688 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1690 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1691 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1693 // Add the "thunk" attribute so that LLVM knows that the return type is
1694 // meaningless. These thunks can be used to call functions with differing
1695 // return types, and the caller is required to cast the prototype
1696 // appropriately to extract the correct value.
1697 ThunkFn->addFnAttr("thunk");
1699 // These thunks can be compared, so they are not unnamed.
1700 ThunkFn->setUnnamedAddr(false);
1703 CodeGenFunction CGF(CGM);
1704 CGF.CurGD = GlobalDecl(MD);
1705 CGF.CurFuncIsThunk = true;
1707 // Build FunctionArgs, but only include the implicit 'this' parameter
1709 FunctionArgList FunctionArgs;
1710 buildThisParam(CGF, FunctionArgs);
1712 // Start defining the function.
1713 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1714 FunctionArgs, MD->getLocation(), SourceLocation());
1717 // Load the vfptr and then callee from the vftable. The callee should have
1718 // adjusted 'this' so that the vfptr is at offset zero.
1719 llvm::Value *VTable = CGF.GetVTablePtr(
1720 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1721 llvm::Value *VFuncPtr =
1722 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1723 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1725 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1730 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1731 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1732 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1733 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1734 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1735 if (GV->isDeclaration())
1736 emitVBTableDefinition(*VBT, RD, GV);
1740 llvm::GlobalVariable *
1741 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1742 llvm::GlobalVariable::LinkageTypes Linkage) {
1743 SmallString<256> OutName;
1744 llvm::raw_svector_ostream Out(OutName);
1745 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1747 StringRef Name = OutName.str();
1749 llvm::ArrayType *VBTableType =
1750 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1752 assert(!CGM.getModule().getNamedGlobal(Name) &&
1753 "vbtable with this name already exists: mangling bug?");
1754 llvm::GlobalVariable *GV =
1755 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1756 GV->setUnnamedAddr(true);
1758 if (RD->hasAttr<DLLImportAttr>())
1759 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1760 else if (RD->hasAttr<DLLExportAttr>())
1761 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1763 if (!GV->hasExternalLinkage())
1764 emitVBTableDefinition(VBT, RD, GV);
1769 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1770 const CXXRecordDecl *RD,
1771 llvm::GlobalVariable *GV) const {
1772 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1774 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1775 "should only emit vbtables for classes with vbtables");
1777 const ASTRecordLayout &BaseLayout =
1778 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1779 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1781 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1784 // The offset from ReusingBase's vbptr to itself always leads.
1785 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1786 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1788 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1789 for (const auto &I : ReusingBase->vbases()) {
1790 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1791 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1792 assert(!Offset.isNegative());
1794 // Make it relative to the subobject vbptr.
1795 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1796 if (VBT.getVBaseWithVPtr())
1797 CompleteVBPtrOffset +=
1798 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1799 Offset -= CompleteVBPtrOffset;
1801 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1802 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1803 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1806 assert(Offsets.size() ==
1807 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1808 ->getElementType())->getNumElements());
1809 llvm::ArrayType *VBTableType =
1810 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1811 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1812 GV->setInitializer(Init);
1815 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1817 const ThisAdjustment &TA) {
1821 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1823 if (!TA.Virtual.isEmpty()) {
1824 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1825 // Adjust the this argument based on the vtordisp value.
1826 llvm::Value *VtorDispPtr =
1827 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1829 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1830 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1831 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1833 if (TA.Virtual.Microsoft.VBPtrOffset) {
1834 // If the final overrider is defined in a virtual base other than the one
1835 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1836 // the vbtable of the derived class.
1837 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1838 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1840 llvm::Value *VBaseOffset =
1841 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1842 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1843 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1847 if (TA.NonVirtual) {
1848 // Non-virtual adjustment might result in a pointer outside the allocated
1849 // object, e.g. if the final overrider class is laid out after the virtual
1850 // base that declares a method in the most derived class.
1851 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1854 // Don't need to bitcast back, the call CodeGen will handle this.
1859 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1860 const ReturnAdjustment &RA) {
1864 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1866 if (RA.Virtual.Microsoft.VBIndex) {
1867 assert(RA.Virtual.Microsoft.VBIndex > 0);
1868 const ASTContext &Context = getContext();
1869 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
1871 llvm::Value *VBaseOffset =
1872 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1873 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1874 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1878 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
1880 // Cast back to the original type.
1881 return CGF.Builder.CreateBitCast(V, Ret->getType());
1884 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1885 QualType elementType) {
1886 // Microsoft seems to completely ignore the possibility of a
1887 // two-argument usual deallocation function.
1888 return elementType.isDestructedType();
1891 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1892 // Microsoft seems to completely ignore the possibility of a
1893 // two-argument usual deallocation function.
1894 return expr->getAllocatedType().isDestructedType();
1897 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1898 // The array cookie is always a size_t; we then pad that out to the
1899 // alignment of the element type.
1900 ASTContext &Ctx = getContext();
1901 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1902 Ctx.getTypeAlignInChars(type));
1905 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1906 llvm::Value *allocPtr,
1907 CharUnits cookieSize) {
1908 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1909 llvm::Value *numElementsPtr =
1910 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1911 return CGF.Builder.CreateLoad(numElementsPtr);
1914 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1915 llvm::Value *newPtr,
1916 llvm::Value *numElements,
1917 const CXXNewExpr *expr,
1918 QualType elementType) {
1919 assert(requiresArrayCookie(expr));
1921 // The size of the cookie.
1922 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1924 // Compute an offset to the cookie.
1925 llvm::Value *cookiePtr = newPtr;
1927 // Write the number of elements into the appropriate slot.
1928 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1929 llvm::Value *numElementsPtr
1930 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1931 CGF.Builder.CreateStore(numElements, numElementsPtr);
1933 // Finally, compute a pointer to the actual data buffer by skipping
1934 // over the cookie completely.
1935 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1936 cookieSize.getQuantity());
1939 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
1940 llvm::Constant *Dtor,
1941 llvm::Constant *Addr) {
1942 // Create a function which calls the destructor.
1943 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
1945 // extern "C" int __tlregdtor(void (*f)(void));
1946 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
1947 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
1949 llvm::Constant *TLRegDtor =
1950 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
1951 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
1952 TLRegDtorFn->setDoesNotThrow();
1954 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
1957 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
1958 llvm::Constant *Dtor,
1959 llvm::Constant *Addr) {
1961 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
1963 // The default behavior is to use atexit.
1964 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
1967 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
1969 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
1971 ArrayRef<llvm::Function *> CXXThreadLocalInits,
1972 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
1973 // This will create a GV in the .CRT$XDU section. It will point to our
1974 // initialization function. The CRT will call all of these function
1975 // pointers at start-up time and, eventually, at thread-creation time.
1976 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
1977 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
1978 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
1979 llvm::GlobalVariable::InternalLinkage, InitFunc,
1980 Twine(InitFunc->getName(), "$initializer$"));
1981 InitFuncPtr->setSection(".CRT$XDU");
1982 // This variable has discardable linkage, we have to add it to @llvm.used to
1983 // ensure it won't get discarded.
1984 CGM.addUsedGlobal(InitFuncPtr);
1988 std::vector<llvm::Function *> NonComdatInits;
1989 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
1990 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
1991 llvm::Function *F = CXXThreadLocalInits[I];
1993 // If the GV is already in a comdat group, then we have to join it.
1994 if (llvm::Comdat *C = GV->getComdat())
1995 AddToXDU(F)->setComdat(C);
1997 NonComdatInits.push_back(F);
2000 if (!NonComdatInits.empty()) {
2001 llvm::FunctionType *FTy =
2002 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2003 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2004 FTy, "__tls_init", SourceLocation(),
2006 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2012 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2014 QualType LValType) {
2015 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2019 static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) {
2020 StringRef VarName("_Init_thread_epoch");
2021 if (auto *GV = CGM.getModule().getNamedGlobal(VarName))
2023 auto *GV = new llvm::GlobalVariable(
2024 CGM.getModule(), CGM.IntTy,
2025 /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage,
2026 /*Initializer=*/nullptr, VarName,
2027 /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel);
2028 GV->setAlignment(CGM.getTarget().getIntAlign() / 8);
2032 static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) {
2033 llvm::FunctionType *FTy =
2034 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2035 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2036 return CGM.CreateRuntimeFunction(
2037 FTy, "_Init_thread_header",
2038 llvm::AttributeSet::get(CGM.getLLVMContext(),
2039 llvm::AttributeSet::FunctionIndex,
2040 llvm::Attribute::NoUnwind));
2043 static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) {
2044 llvm::FunctionType *FTy =
2045 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2046 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2047 return CGM.CreateRuntimeFunction(
2048 FTy, "_Init_thread_footer",
2049 llvm::AttributeSet::get(CGM.getLLVMContext(),
2050 llvm::AttributeSet::FunctionIndex,
2051 llvm::Attribute::NoUnwind));
2054 static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) {
2055 llvm::FunctionType *FTy =
2056 llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()),
2057 CGM.IntTy->getPointerTo(), /*isVarArg=*/false);
2058 return CGM.CreateRuntimeFunction(
2059 FTy, "_Init_thread_abort",
2060 llvm::AttributeSet::get(CGM.getLLVMContext(),
2061 llvm::AttributeSet::FunctionIndex,
2062 llvm::Attribute::NoUnwind));
2066 struct ResetGuardBit : EHScopeStack::Cleanup {
2067 llvm::GlobalVariable *Guard;
2069 ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum)
2070 : Guard(Guard), GuardNum(GuardNum) {}
2072 void Emit(CodeGenFunction &CGF, Flags flags) override {
2073 // Reset the bit in the mask so that the static variable may be
2075 CGBuilderTy &Builder = CGF.Builder;
2076 llvm::LoadInst *LI = Builder.CreateLoad(Guard);
2077 llvm::ConstantInt *Mask =
2078 llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum));
2079 Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard);
2083 struct CallInitThreadAbort : EHScopeStack::Cleanup {
2084 llvm::GlobalVariable *Guard;
2085 CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {}
2087 void Emit(CodeGenFunction &CGF, Flags flags) override {
2088 // Calling _Init_thread_abort will reset the guard's state.
2089 CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard);
2094 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2095 llvm::GlobalVariable *GV,
2097 // MSVC only uses guards for static locals.
2098 if (!D.isStaticLocal()) {
2099 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2100 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2101 llvm::Function *F = CGF.CurFn;
2102 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2103 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2104 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2108 bool ThreadlocalStatic = D.getTLSKind();
2109 bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics;
2111 // Thread-safe static variables which aren't thread-specific have a
2112 // per-variable guard.
2113 bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic;
2115 CGBuilderTy &Builder = CGF.Builder;
2116 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2117 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2119 // Get the guard variable for this function if we have one already.
2120 GuardInfo *GI = nullptr;
2121 if (ThreadlocalStatic)
2122 GI = &ThreadLocalGuardVariableMap[D.getDeclContext()];
2123 else if (!ThreadsafeStatic)
2124 GI = &GuardVariableMap[D.getDeclContext()];
2126 llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr;
2128 if (D.isExternallyVisible()) {
2129 // Externally visible variables have to be numbered in Sema to properly
2130 // handle unreachable VarDecls.
2131 GuardNum = getContext().getStaticLocalNumber(&D);
2132 assert(GuardNum > 0);
2134 } else if (HasPerVariableGuard) {
2135 GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++;
2137 // Non-externally visible variables are numbered here in CodeGen.
2138 GuardNum = GI->BitIndex++;
2141 if (!HasPerVariableGuard && GuardNum >= 32) {
2142 if (D.isExternallyVisible())
2143 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2149 // Mangle the name for the guard.
2150 SmallString<256> GuardName;
2152 llvm::raw_svector_ostream Out(GuardName);
2153 if (HasPerVariableGuard)
2154 getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum,
2157 getMangleContext().mangleStaticGuardVariable(&D, Out);
2161 // Create the guard variable with a zero-initializer. Just absorb linkage,
2162 // visibility and dll storage class from the guarded variable.
2164 new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false,
2165 GV->getLinkage(), Zero, GuardName.str());
2166 GuardVar->setVisibility(GV->getVisibility());
2167 GuardVar->setDLLStorageClass(GV->getDLLStorageClass());
2168 if (GuardVar->isWeakForLinker())
2169 GuardVar->setComdat(
2170 CGM.getModule().getOrInsertComdat(GuardVar->getName()));
2172 GuardVar->setThreadLocal(true);
2173 if (GI && !HasPerVariableGuard)
2174 GI->Guard = GuardVar;
2177 assert(GuardVar->getLinkage() == GV->getLinkage() &&
2178 "static local from the same function had different linkage");
2180 if (!HasPerVariableGuard) {
2181 // Pseudo code for the test:
2182 // if (!(GuardVar & MyGuardBit)) {
2183 // GuardVar |= MyGuardBit;
2184 // ... initialize the object ...;
2187 // Test our bit from the guard variable.
2188 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum);
2189 llvm::LoadInst *LI = Builder.CreateLoad(GuardVar);
2190 llvm::Value *IsInitialized =
2191 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2192 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2193 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2194 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2196 // Set our bit in the guard variable and emit the initializer and add a global
2197 // destructor if appropriate.
2198 CGF.EmitBlock(InitBlock);
2199 Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardVar);
2200 CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum);
2201 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2202 CGF.PopCleanupBlock();
2203 Builder.CreateBr(EndBlock);
2206 CGF.EmitBlock(EndBlock);
2208 // Pseudo code for the test:
2209 // if (TSS > _Init_thread_epoch) {
2210 // _Init_thread_header(&TSS);
2212 // ... initialize the object ...;
2213 // _Init_thread_footer(&TSS);
2217 // The algorithm is almost identical to what can be found in the appendix
2220 unsigned IntAlign = CGM.getTarget().getIntAlign() / 8;
2222 // This BasicBLock determines whether or not we have any work to do.
2223 llvm::LoadInst *FirstGuardLoad =
2224 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2225 FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2226 llvm::LoadInst *InitThreadEpoch =
2227 Builder.CreateLoad(getInitThreadEpochPtr(CGM));
2228 llvm::Value *IsUninitialized =
2229 Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch);
2230 llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt");
2231 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2232 Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock);
2234 // This BasicBlock attempts to determine whether or not this thread is
2235 // responsible for doing the initialization.
2236 CGF.EmitBlock(AttemptInitBlock);
2237 CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar);
2238 llvm::LoadInst *SecondGuardLoad =
2239 Builder.CreateAlignedLoad(GuardVar, IntAlign);
2240 SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered);
2241 llvm::Value *ShouldDoInit =
2242 Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt());
2243 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2244 Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock);
2246 // Ok, we ended up getting selected as the initializing thread.
2247 CGF.EmitBlock(InitBlock);
2248 CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar);
2249 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2250 CGF.PopCleanupBlock();
2251 CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar);
2252 Builder.CreateBr(EndBlock);
2254 CGF.EmitBlock(EndBlock);
2258 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2259 // Null-ness for function memptrs only depends on the first field, which is
2260 // the function pointer. The rest don't matter, so we can zero initialize.
2261 if (MPT->isMemberFunctionPointer())
2264 // The virtual base adjustment field is always -1 for null, so if we have one
2265 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2266 // valid field offset.
2267 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2268 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2269 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2270 RD->nullFieldOffsetIsZero());
2274 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2275 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2276 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2277 llvm::SmallVector<llvm::Type *, 4> fields;
2278 if (MPT->isMemberFunctionPointer())
2279 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2281 fields.push_back(CGM.IntTy); // FieldOffset
2283 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2285 fields.push_back(CGM.IntTy);
2286 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2287 fields.push_back(CGM.IntTy);
2288 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2289 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2291 if (fields.size() == 1)
2293 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2296 void MicrosoftCXXABI::
2297 GetNullMemberPointerFields(const MemberPointerType *MPT,
2298 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2299 assert(fields.empty());
2300 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2301 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2302 if (MPT->isMemberFunctionPointer()) {
2303 // FunctionPointerOrVirtualThunk
2304 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2306 if (RD->nullFieldOffsetIsZero())
2307 fields.push_back(getZeroInt()); // FieldOffset
2309 fields.push_back(getAllOnesInt()); // FieldOffset
2312 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2314 fields.push_back(getZeroInt());
2315 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2316 fields.push_back(getZeroInt());
2317 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2318 fields.push_back(getAllOnesInt());
2322 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2323 llvm::SmallVector<llvm::Constant *, 4> fields;
2324 GetNullMemberPointerFields(MPT, fields);
2325 if (fields.size() == 1)
2327 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2328 assert(Res->getType() == ConvertMemberPointerType(MPT));
2333 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2334 bool IsMemberFunction,
2335 const CXXRecordDecl *RD,
2336 CharUnits NonVirtualBaseAdjustment,
2337 unsigned VBTableIndex) {
2338 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2340 // Single inheritance class member pointer are represented as scalars instead
2342 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2345 llvm::SmallVector<llvm::Constant *, 4> fields;
2346 fields.push_back(FirstField);
2348 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2349 fields.push_back(llvm::ConstantInt::get(
2350 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2352 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2353 CharUnits Offs = CharUnits::Zero();
2354 if (RD->getNumVBases())
2355 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2356 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2359 // The rest of the fields are adjusted by conversions to a more derived class.
2360 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2361 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex));
2363 return llvm::ConstantStruct::getAnon(fields);
2367 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2369 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2370 llvm::Constant *FirstField =
2371 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2372 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2373 CharUnits::Zero(), /*VBTableIndex=*/0);
2376 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
2377 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
2380 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2382 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
2383 const ValueDecl *MPD = MP.getMemberPointerDecl();
2385 return EmitNullMemberPointer(MPT);
2387 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
2389 // FIXME PR15713: Support virtual inheritance paths.
2391 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
2392 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
2395 CharUnits FieldOffset =
2396 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
2397 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
2401 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
2402 const CXXMethodDecl *MD,
2403 CharUnits NonVirtualBaseAdjustment) {
2404 assert(MD->isInstance() && "Member function must not be static!");
2405 MD = MD->getCanonicalDecl();
2406 RD = RD->getMostRecentDecl();
2407 CodeGenTypes &Types = CGM.getTypes();
2409 unsigned VBTableIndex = 0;
2410 llvm::Constant *FirstField;
2411 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2412 if (!MD->isVirtual()) {
2414 // Check whether the function has a computable LLVM signature.
2415 if (Types.isFuncTypeConvertible(FPT)) {
2416 // The function has a computable LLVM signature; use the correct type.
2417 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2419 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2420 // function type is incomplete.
2423 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2424 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2426 if (!CGM.getTypes().isFuncTypeConvertible(
2427 MD->getType()->castAs<FunctionType>())) {
2428 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
2429 "incomplete return or parameter type");
2430 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2431 } else if (FPT->getCallConv() == CC_X86FastCall) {
2432 CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
2433 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2435 auto &VTableContext = CGM.getMicrosoftVTableContext();
2436 MicrosoftVTableContext::MethodVFTableLocation ML =
2437 VTableContext.getMethodVFTableLocation(MD);
2438 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2439 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2440 // Include the vfptr adjustment if the method is in a non-primary vftable.
2441 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2443 VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
2447 // The rest of the fields are common with data member pointers.
2448 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2449 NonVirtualBaseAdjustment, VBTableIndex);
2452 /// Member pointers are the same if they're either bitwise identical *or* both
2453 /// null. Null-ness for function members is determined by the first field,
2454 /// while for data member pointers we must compare all fields.
2456 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2459 const MemberPointerType *MPT,
2461 CGBuilderTy &Builder = CGF.Builder;
2463 // Handle != comparisons by switching the sense of all boolean operations.
2464 llvm::ICmpInst::Predicate Eq;
2465 llvm::Instruction::BinaryOps And, Or;
2467 Eq = llvm::ICmpInst::ICMP_NE;
2468 And = llvm::Instruction::Or;
2469 Or = llvm::Instruction::And;
2471 Eq = llvm::ICmpInst::ICMP_EQ;
2472 And = llvm::Instruction::And;
2473 Or = llvm::Instruction::Or;
2476 // If this is a single field member pointer (single inheritance), this is a
2478 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2479 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2480 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2482 return Builder.CreateICmp(Eq, L, R);
2484 // Compare the first field.
2485 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2486 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2487 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2489 // Compare everything other than the first field.
2490 llvm::Value *Res = nullptr;
2491 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2492 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2493 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2494 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2495 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2497 Res = Builder.CreateBinOp(And, Res, Cmp);
2502 // Check if the first field is 0 if this is a function pointer.
2503 if (MPT->isMemberFunctionPointer()) {
2504 // (l1 == r1 && ...) || l0 == 0
2505 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2506 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2507 Res = Builder.CreateBinOp(Or, Res, IsZero);
2510 // Combine the comparison of the first field, which must always be true for
2511 // this comparison to succeeed.
2512 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2516 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2517 llvm::Value *MemPtr,
2518 const MemberPointerType *MPT) {
2519 CGBuilderTy &Builder = CGF.Builder;
2520 llvm::SmallVector<llvm::Constant *, 4> fields;
2521 // We only need one field for member functions.
2522 if (MPT->isMemberFunctionPointer())
2523 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2525 GetNullMemberPointerFields(MPT, fields);
2526 assert(!fields.empty());
2527 llvm::Value *FirstField = MemPtr;
2528 if (MemPtr->getType()->isStructTy())
2529 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2530 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2532 // For function member pointers, we only need to test the function pointer
2533 // field. The other fields if any can be garbage.
2534 if (MPT->isMemberFunctionPointer())
2537 // Otherwise, emit a series of compares and combine the results.
2538 for (int I = 1, E = fields.size(); I < E; ++I) {
2539 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2540 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2541 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2546 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2547 llvm::Constant *Val) {
2548 // Function pointers are null if the pointer in the first field is null.
2549 if (MPT->isMemberFunctionPointer()) {
2550 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2551 Val->getAggregateElement(0U) : Val;
2552 return FirstField->isNullValue();
2555 // If it's not a function pointer and it's zero initializable, we can easily
2557 if (isZeroInitializable(MPT) && Val->isNullValue())
2560 // Otherwise, break down all the fields for comparison. Hopefully these
2561 // little Constants are reused, while a big null struct might not be.
2562 llvm::SmallVector<llvm::Constant *, 4> Fields;
2563 GetNullMemberPointerFields(MPT, Fields);
2564 if (Fields.size() == 1) {
2565 assert(Val->getType()->isIntegerTy());
2566 return Val == Fields[0];
2570 for (I = 0, E = Fields.size(); I != E; ++I) {
2571 if (Val->getAggregateElement(I) != Fields[I])
2578 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2580 llvm::Value *VBPtrOffset,
2581 llvm::Value *VBTableOffset,
2582 llvm::Value **VBPtrOut) {
2583 CGBuilderTy &Builder = CGF.Builder;
2584 // Load the vbtable pointer from the vbptr in the instance.
2585 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2586 llvm::Value *VBPtr =
2587 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2588 if (VBPtrOut) *VBPtrOut = VBPtr;
2589 VBPtr = Builder.CreateBitCast(VBPtr,
2590 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2591 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2593 // Translate from byte offset to table index. It improves analyzability.
2594 llvm::Value *VBTableIndex = Builder.CreateAShr(
2595 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2596 "vbtindex", /*isExact=*/true);
2598 // Load an i32 offset from the vb-table.
2599 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2600 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2601 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2604 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2606 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2607 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2608 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2609 CGBuilderTy &Builder = CGF.Builder;
2610 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2611 llvm::BasicBlock *OriginalBB = nullptr;
2612 llvm::BasicBlock *SkipAdjustBB = nullptr;
2613 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2615 // In the unspecified inheritance model, there might not be a vbtable at all,
2616 // in which case we need to skip the virtual base lookup. If there is a
2617 // vbtable, the first entry is a no-op entry that gives back the original
2618 // base, so look for a virtual base adjustment offset of zero.
2620 OriginalBB = Builder.GetInsertBlock();
2621 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2622 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2623 llvm::Value *IsVirtual =
2624 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2626 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2627 CGF.EmitBlock(VBaseAdjustBB);
2630 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2631 // know the vbptr offset.
2633 CharUnits offs = CharUnits::Zero();
2634 if (!RD->hasDefinition()) {
2635 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2636 unsigned DiagID = Diags.getCustomDiagID(
2637 DiagnosticsEngine::Error,
2638 "member pointer representation requires a "
2639 "complete class type for %0 to perform this expression");
2640 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2641 } else if (RD->getNumVBases())
2642 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2643 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2645 llvm::Value *VBPtr = nullptr;
2646 llvm::Value *VBaseOffs =
2647 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2648 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2650 // Merge control flow with the case where we didn't have to adjust.
2651 if (VBaseAdjustBB) {
2652 Builder.CreateBr(SkipAdjustBB);
2653 CGF.EmitBlock(SkipAdjustBB);
2654 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2655 Phi->addIncoming(Base, OriginalBB);
2656 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2659 return AdjustedBase;
2662 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2663 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2664 const MemberPointerType *MPT) {
2665 assert(MPT->isMemberDataPointer());
2666 unsigned AS = Base->getType()->getPointerAddressSpace();
2668 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2669 CGBuilderTy &Builder = CGF.Builder;
2670 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2671 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2673 // Extract the fields we need, regardless of model. We'll apply them if we
2675 llvm::Value *FieldOffset = MemPtr;
2676 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2677 llvm::Value *VBPtrOffset = nullptr;
2678 if (MemPtr->getType()->isStructTy()) {
2679 // We need to extract values.
2681 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2682 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2683 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2684 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2685 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2688 if (VirtualBaseAdjustmentOffset) {
2689 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2694 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2696 // Apply the offset, which we assume is non-null.
2698 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2700 // Cast the address to the appropriate pointer type, adopting the address
2701 // space of the base pointer.
2702 return Builder.CreateBitCast(Addr, PType);
2705 static MSInheritanceAttr::Spelling
2706 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2707 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2711 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2714 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2715 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2716 E->getCastKind() == CK_ReinterpretMemberPointer);
2718 // Use constant emission if we can.
2719 if (isa<llvm::Constant>(Src))
2720 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2722 // We may be adding or dropping fields from the member pointer, so we need
2723 // both types and the inheritance models of both records.
2724 const MemberPointerType *SrcTy =
2725 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2726 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2727 bool IsFunc = SrcTy->isMemberFunctionPointer();
2729 // If the classes use the same null representation, reinterpret_cast is a nop.
2730 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2731 if (IsReinterpret && IsFunc)
2734 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2735 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2736 if (IsReinterpret &&
2737 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2740 CGBuilderTy &Builder = CGF.Builder;
2742 // Branch past the conversion if Src is null.
2743 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2744 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2746 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2747 // pointer value of the destination type.
2748 if (IsReinterpret) {
2749 // For reinterpret casts, sema ensures that src and dst are both functions
2750 // or data and have the same size, which means the LLVM types should match.
2751 assert(Src->getType() == DstNull->getType());
2752 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2755 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2756 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2757 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2758 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2759 CGF.EmitBlock(ConvertBB);
2762 llvm::Value *FirstField = Src;
2763 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2764 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2765 llvm::Value *VBPtrOffset = nullptr;
2766 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2767 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2768 // We need to extract values.
2770 FirstField = Builder.CreateExtractValue(Src, I++);
2771 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2772 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2773 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2774 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2775 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2776 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2779 // For data pointers, we adjust the field offset directly. For functions, we
2780 // have a separate field.
2781 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2783 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2784 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2785 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2786 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2787 NVAdjustField = getZeroInt();
2788 if (isDerivedToBase)
2789 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2791 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2794 // FIXME PR15713: Support conversions through virtually derived classes.
2796 // Recompose dst from the null struct and the adjusted fields from src.
2797 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2799 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2802 Dst = llvm::UndefValue::get(DstNull->getType());
2804 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2805 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2806 Dst = Builder.CreateInsertValue(
2807 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2808 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2809 Dst = Builder.CreateInsertValue(
2810 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2811 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2812 Dst = Builder.CreateInsertValue(
2813 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2815 Builder.CreateBr(ContinueBB);
2817 // In the continuation, choose between DstNull and Dst.
2818 CGF.EmitBlock(ContinueBB);
2819 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2820 Phi->addIncoming(DstNull, OriginalBB);
2821 Phi->addIncoming(Dst, ConvertBB);
2826 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2827 llvm::Constant *Src) {
2828 const MemberPointerType *SrcTy =
2829 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2830 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2832 // If src is null, emit a new null for dst. We can't return src because dst
2833 // might have a new representation.
2834 if (MemberPointerConstantIsNull(SrcTy, Src))
2835 return EmitNullMemberPointer(DstTy);
2837 // We don't need to do anything for reinterpret_casts of non-null member
2838 // pointers. We should only get here when the two type representations have
2840 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2843 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2844 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2847 llvm::Constant *FirstField = Src;
2848 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2849 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2850 llvm::Constant *VBPtrOffset = nullptr;
2851 bool IsFunc = SrcTy->isMemberFunctionPointer();
2852 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2853 // We need to extract values.
2855 FirstField = Src->getAggregateElement(I++);
2856 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2857 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2858 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2859 VBPtrOffset = Src->getAggregateElement(I++);
2860 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2861 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2864 // For data pointers, we adjust the field offset directly. For functions, we
2865 // have a separate field.
2866 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2868 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2869 llvm::Constant *&NVAdjustField =
2870 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2871 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2872 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2873 NVAdjustField = getZeroInt();
2874 if (IsDerivedToBase)
2875 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2877 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2880 // FIXME PR15713: Support conversions through virtually derived classes.
2882 // Recompose dst from the null struct and the adjusted fields from src.
2883 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2886 llvm::SmallVector<llvm::Constant *, 4> Fields;
2887 Fields.push_back(FirstField);
2888 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2889 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2890 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2891 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2892 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2893 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2894 return llvm::ConstantStruct::getAnon(Fields);
2897 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2898 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2899 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2900 assert(MPT->isMemberFunctionPointer());
2901 const FunctionProtoType *FPT =
2902 MPT->getPointeeType()->castAs<FunctionProtoType>();
2903 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2904 llvm::FunctionType *FTy =
2905 CGM.getTypes().GetFunctionType(
2906 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2907 CGBuilderTy &Builder = CGF.Builder;
2909 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2911 // Extract the fields we need, regardless of model. We'll apply them if we
2913 llvm::Value *FunctionPointer = MemPtr;
2914 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2915 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2916 llvm::Value *VBPtrOffset = nullptr;
2917 if (MemPtr->getType()->isStructTy()) {
2918 // We need to extract values.
2920 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2921 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2922 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2923 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2924 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2925 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2926 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2929 if (VirtualBaseAdjustmentOffset) {
2930 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2934 if (NonVirtualBaseAdjustment) {
2935 // Apply the adjustment and cast back to the original struct type.
2936 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2937 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2938 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2941 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2944 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2945 return new MicrosoftCXXABI(CGM);
2948 // MS RTTI Overview:
2949 // The run time type information emitted by cl.exe contains 5 distinct types of
2950 // structures. Many of them reference each other.
2952 // TypeInfo: Static classes that are returned by typeid.
2954 // CompleteObjectLocator: Referenced by vftables. They contain information
2955 // required for dynamic casting, including OffsetFromTop. They also contain
2956 // a reference to the TypeInfo for the type and a reference to the
2957 // CompleteHierarchyDescriptor for the type.
2959 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2960 // Used during dynamic_cast to walk a class hierarchy. References a base
2961 // class array and the size of said array.
2963 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2964 // somewhat of a misnomer because the most derived class is also in the list
2965 // as well as multiple copies of virtual bases (if they occur multiple times
2966 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2967 // every path in the hierarchy, in pre-order depth first order. Note, we do
2968 // not declare a specific llvm type for BaseClassArray, it's merely an array
2969 // of BaseClassDescriptor pointers.
2971 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2972 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2973 // BaseClassArray is. It contains information about a class within a
2974 // hierarchy such as: is this base is ambiguous and what is its offset in the
2975 // vbtable. The names of the BaseClassDescriptors have all of their fields
2976 // mangled into them so they can be aggressively deduplicated by the linker.
2978 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2979 StringRef MangledName("\01??_7type_info@@6B@");
2980 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2982 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2984 llvm::GlobalVariable::ExternalLinkage,
2985 /*Initializer=*/nullptr, MangledName);
2990 /// \brief A Helper struct that stores information about a class in a class
2991 /// hierarchy. The information stored in these structs struct is used during
2992 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2993 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2994 // implicit depth first pre-order tree connectivity. getFirstChild and
2995 // getNextSibling allow us to walk the tree efficiently.
2996 struct MSRTTIClass {
2998 IsPrivateOnPath = 1 | 8,
3002 HasHierarchyDescriptor = 64
3004 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
3005 uint32_t initialize(const MSRTTIClass *Parent,
3006 const CXXBaseSpecifier *Specifier);
3008 MSRTTIClass *getFirstChild() { return this + 1; }
3009 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
3010 return Child + 1 + Child->NumBases;
3013 const CXXRecordDecl *RD, *VirtualRoot;
3014 uint32_t Flags, NumBases, OffsetInVBase;
3017 /// \brief Recursively initialize the base class array.
3018 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
3019 const CXXBaseSpecifier *Specifier) {
3020 Flags = HasHierarchyDescriptor;
3022 VirtualRoot = nullptr;
3025 if (Specifier->getAccessSpecifier() != AS_public)
3026 Flags |= IsPrivate | IsPrivateOnPath;
3027 if (Specifier->isVirtual()) {
3032 if (Parent->Flags & IsPrivateOnPath)
3033 Flags |= IsPrivateOnPath;
3034 VirtualRoot = Parent->VirtualRoot;
3035 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
3036 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
3040 MSRTTIClass *Child = getFirstChild();
3041 for (const CXXBaseSpecifier &Base : RD->bases()) {
3042 NumBases += Child->initialize(this, &Base) + 1;
3043 Child = getNextChild(Child);
3048 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
3049 switch (Ty->getLinkage()) {
3051 case InternalLinkage:
3052 case UniqueExternalLinkage:
3053 return llvm::GlobalValue::InternalLinkage;
3055 case VisibleNoLinkage:
3056 case ExternalLinkage:
3057 return llvm::GlobalValue::LinkOnceODRLinkage;
3059 llvm_unreachable("Invalid linkage!");
3062 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
3063 /// calls to the module and information about the most derived class in a
3065 struct MSRTTIBuilder {
3067 HasBranchingHierarchy = 1,
3068 HasVirtualBranchingHierarchy = 2,
3069 HasAmbiguousBases = 4
3072 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
3073 : CGM(ABI.CGM), Context(CGM.getContext()),
3074 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
3075 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
3078 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
3079 llvm::GlobalVariable *
3080 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
3081 llvm::GlobalVariable *getClassHierarchyDescriptor();
3082 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
3085 ASTContext &Context;
3086 llvm::LLVMContext &VMContext;
3087 llvm::Module &Module;
3088 const CXXRecordDecl *RD;
3089 llvm::GlobalVariable::LinkageTypes Linkage;
3090 MicrosoftCXXABI &ABI;
3095 /// \brief Recursively serializes a class hierarchy in pre-order depth first
3097 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
3098 const CXXRecordDecl *RD) {
3099 Classes.push_back(MSRTTIClass(RD));
3100 for (const CXXBaseSpecifier &Base : RD->bases())
3101 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
3104 /// \brief Find ambiguity among base classes.
3106 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
3107 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
3108 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
3109 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
3110 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
3111 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
3112 !VirtualBases.insert(Class->RD).second) {
3113 Class = MSRTTIClass::getNextChild(Class);
3116 if (!UniqueBases.insert(Class->RD).second)
3117 AmbiguousBases.insert(Class->RD);
3120 if (AmbiguousBases.empty())
3122 for (MSRTTIClass &Class : Classes)
3123 if (AmbiguousBases.count(Class.RD))
3124 Class.Flags |= MSRTTIClass::IsAmbiguous;
3127 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
3128 SmallString<256> MangledName;
3130 llvm::raw_svector_ostream Out(MangledName);
3131 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
3134 // Check to see if we've already declared this ClassHierarchyDescriptor.
3135 if (auto CHD = Module.getNamedGlobal(MangledName))
3138 // Serialize the class hierarchy and initialize the CHD Fields.
3139 SmallVector<MSRTTIClass, 8> Classes;
3140 serializeClassHierarchy(Classes, RD);
3141 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3142 detectAmbiguousBases(Classes);
3144 for (auto Class : Classes) {
3145 if (Class.RD->getNumBases() > 1)
3146 Flags |= HasBranchingHierarchy;
3147 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3148 // believe the field isn't actually used.
3149 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3150 Flags |= HasAmbiguousBases;
3152 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3153 Flags |= HasVirtualBranchingHierarchy;
3154 // These gep indices are used to get the address of the first element of the
3155 // base class array.
3156 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3157 llvm::ConstantInt::get(CGM.IntTy, 0)};
3159 // Forward-declare the class hierarchy descriptor
3160 auto Type = ABI.getClassHierarchyDescriptorType();
3161 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3162 /*Initializer=*/nullptr,
3163 StringRef(MangledName));
3164 if (CHD->isWeakForLinker())
3165 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3167 auto *Bases = getBaseClassArray(Classes);
3169 // Initialize the base class ClassHierarchyDescriptor.
3170 llvm::Constant *Fields[] = {
3171 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3172 llvm::ConstantInt::get(CGM.IntTy, Flags),
3173 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3174 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3175 Bases->getValueType(), Bases,
3176 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3178 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3182 llvm::GlobalVariable *
3183 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3184 SmallString<256> MangledName;
3186 llvm::raw_svector_ostream Out(MangledName);
3187 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3190 // Forward-declare the base class array.
3191 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3192 // mode) bytes of padding. We provide a pointer sized amount of padding by
3193 // adding +1 to Classes.size(). The sections have pointer alignment and are
3194 // marked pick-any so it shouldn't matter.
3195 llvm::Type *PtrType = ABI.getImageRelativeType(
3196 ABI.getBaseClassDescriptorType()->getPointerTo());
3197 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3199 new llvm::GlobalVariable(Module, ArrType,
3200 /*Constant=*/true, Linkage,
3201 /*Initializer=*/nullptr, StringRef(MangledName));
3202 if (BCA->isWeakForLinker())
3203 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3205 // Initialize the BaseClassArray.
3206 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3207 for (MSRTTIClass &Class : Classes)
3208 BaseClassArrayData.push_back(
3209 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3210 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3211 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3215 llvm::GlobalVariable *
3216 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3217 // Compute the fields for the BaseClassDescriptor. They are computed up front
3218 // because they are mangled into the name of the object.
3219 uint32_t OffsetInVBTable = 0;
3220 int32_t VBPtrOffset = -1;
3221 if (Class.VirtualRoot) {
3222 auto &VTableContext = CGM.getMicrosoftVTableContext();
3223 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3224 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3227 SmallString<256> MangledName;
3229 llvm::raw_svector_ostream Out(MangledName);
3230 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3231 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3235 // Check to see if we've already declared this object.
3236 if (auto BCD = Module.getNamedGlobal(MangledName))
3239 // Forward-declare the base class descriptor.
3240 auto Type = ABI.getBaseClassDescriptorType();
3242 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3243 /*Initializer=*/nullptr, StringRef(MangledName));
3244 if (BCD->isWeakForLinker())
3245 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3247 // Initialize the BaseClassDescriptor.
3248 llvm::Constant *Fields[] = {
3249 ABI.getImageRelativeConstant(
3250 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3251 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3252 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3253 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3254 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3255 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3256 ABI.getImageRelativeConstant(
3257 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3259 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3263 llvm::GlobalVariable *
3264 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3265 SmallString<256> MangledName;
3267 llvm::raw_svector_ostream Out(MangledName);
3268 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3271 // Check to see if we've already computed this complete object locator.
3272 if (auto COL = Module.getNamedGlobal(MangledName))
3275 // Compute the fields of the complete object locator.
3276 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3277 int VFPtrOffset = 0;
3278 // The offset includes the vtordisp if one exists.
3279 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3280 if (Context.getASTRecordLayout(RD)
3281 .getVBaseOffsetsMap()
3283 ->second.hasVtorDisp())
3284 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3286 // Forward-declare the complete object locator.
3287 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3288 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3289 /*Initializer=*/nullptr, StringRef(MangledName));
3291 // Initialize the CompleteObjectLocator.
3292 llvm::Constant *Fields[] = {
3293 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3294 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3295 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3296 ABI.getImageRelativeConstant(
3297 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3298 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3299 ABI.getImageRelativeConstant(COL),
3301 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3302 if (!ABI.isImageRelative())
3303 FieldsRef = FieldsRef.drop_back();
3304 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3305 if (COL->isWeakForLinker())
3306 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3310 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3311 bool &IsConst, bool &IsVolatile) {
3312 T = Context.getExceptionObjectType(T);
3314 // C++14 [except.handle]p3:
3315 // A handler is a match for an exception object of type E if [...]
3316 // - the handler is of type cv T or const T& where T is a pointer type and
3317 // E is a pointer type that can be converted to T by [...]
3318 // - a qualification conversion
3321 QualType PointeeType = T->getPointeeType();
3322 if (!PointeeType.isNull()) {
3323 IsConst = PointeeType.isConstQualified();
3324 IsVolatile = PointeeType.isVolatileQualified();
3327 // Member pointer types like "const int A::*" are represented by having RTTI
3328 // for "int A::*" and separately storing the const qualifier.
3329 if (const auto *MPTy = T->getAs<MemberPointerType>())
3330 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3333 // Pointer types like "const int * const *" are represented by having RTTI
3334 // for "const int **" and separately storing the const qualifier.
3335 if (T->isPointerType())
3336 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3342 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3343 QualType CatchHandlerType) {
3344 // TypeDescriptors for exceptions never have qualified pointer types,
3345 // qualifiers are stored seperately in order to support qualification
3347 bool IsConst, IsVolatile;
3348 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3350 bool IsReference = CatchHandlerType->isReferenceType();
3360 SmallString<256> MangledName;
3362 llvm::raw_svector_ostream Out(MangledName);
3363 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3366 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3367 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3369 llvm::Constant *Fields[] = {
3370 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3371 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3373 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3374 auto *Var = new llvm::GlobalVariable(
3375 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3376 llvm::GlobalValue::PrivateLinkage,
3377 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3378 StringRef(MangledName));
3379 Var->setUnnamedAddr(true);
3380 Var->setSection("llvm.metadata");
3384 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3385 /// llvm::GlobalVariable * because different type descriptors have different
3386 /// types, and need to be abstracted. They are abstracting by casting the
3387 /// address to an Int8PtrTy.
3388 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3389 SmallString<256> MangledName;
3391 llvm::raw_svector_ostream Out(MangledName);
3392 getMangleContext().mangleCXXRTTI(Type, Out);
3395 // Check to see if we've already declared this TypeDescriptor.
3396 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3397 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3399 // Compute the fields for the TypeDescriptor.
3400 SmallString<256> TypeInfoString;
3402 llvm::raw_svector_ostream Out(TypeInfoString);
3403 getMangleContext().mangleCXXRTTIName(Type, Out);
3406 // Declare and initialize the TypeDescriptor.
3407 llvm::Constant *Fields[] = {
3408 getTypeInfoVTable(CGM), // VFPtr
3409 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3410 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3411 llvm::StructType *TypeDescriptorType =
3412 getTypeDescriptorType(TypeInfoString);
3413 auto *Var = new llvm::GlobalVariable(
3414 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3415 getLinkageForRTTI(Type),
3416 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3417 StringRef(MangledName));
3418 if (Var->isWeakForLinker())
3419 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3420 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3423 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3424 llvm::GlobalVariable *
3425 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3426 const VPtrInfo *Info) {
3427 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3430 static void emitCXXConstructor(CodeGenModule &CGM,
3431 const CXXConstructorDecl *ctor,
3432 StructorType ctorType) {
3433 // There are no constructor variants, always emit the complete destructor.
3434 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3435 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3438 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3439 StructorType dtorType) {
3440 // The complete destructor is equivalent to the base destructor for
3441 // classes with no virtual bases, so try to emit it as an alias.
3442 if (!dtor->getParent()->getNumVBases() &&
3443 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3444 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3445 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3446 if (ProducedAlias) {
3447 if (dtorType == StructorType::Complete)
3449 if (dtor->isVirtual())
3450 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3454 // The base destructor is equivalent to the base destructor of its
3455 // base class if there is exactly one non-virtual base class with a
3456 // non-trivial destructor, there are no fields with a non-trivial
3457 // destructor, and the body of the destructor is trivial.
3458 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3461 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3462 if (Fn->isWeakForLinker())
3463 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3466 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3467 StructorType Type) {
3468 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3469 emitCXXConstructor(CGM, CD, Type);
3472 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3476 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3478 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3480 // Calculate the mangled name.
3481 SmallString<256> ThunkName;
3482 llvm::raw_svector_ostream Out(ThunkName);
3483 getMangleContext().mangleCXXCtor(CD, CT, Out);
3486 // If the thunk has been generated previously, just return it.
3487 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3488 return cast<llvm::Function>(GV);
3490 // Create the llvm::Function.
3491 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3492 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3493 const CXXRecordDecl *RD = CD->getParent();
3494 QualType RecordTy = getContext().getRecordType(RD);
3495 llvm::Function *ThunkFn = llvm::Function::Create(
3496 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3497 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3498 FnInfo.getEffectiveCallingConvention()));
3499 bool IsCopy = CT == Ctor_CopyingClosure;
3502 CodeGenFunction CGF(CGM);
3503 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3505 // Build FunctionArgs.
3506 FunctionArgList FunctionArgs;
3508 // A constructor always starts with a 'this' pointer as its first argument.
3509 buildThisParam(CGF, FunctionArgs);
3511 // Following the 'this' pointer is a reference to the source object that we
3512 // are copying from.
3513 ImplicitParamDecl SrcParam(
3514 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3515 getContext().getLValueReferenceType(RecordTy,
3516 /*SpelledAsLValue=*/true));
3518 FunctionArgs.push_back(&SrcParam);
3520 // Constructors for classes which utilize virtual bases have an additional
3521 // parameter which indicates whether or not it is being delegated to by a more
3522 // derived constructor.
3523 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3524 &getContext().Idents.get("is_most_derived"),
3525 getContext().IntTy);
3526 // Only add the parameter to the list if thie class has virtual bases.
3527 if (RD->getNumVBases() > 0)
3528 FunctionArgs.push_back(&IsMostDerived);
3530 // Start defining the function.
3531 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3532 FunctionArgs, CD->getLocation(), SourceLocation());
3534 llvm::Value *This = getThisValue(CGF);
3536 llvm::Value *SrcVal =
3537 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3542 // Push the this ptr.
3543 Args.add(RValue::get(This), CD->getThisType(getContext()));
3545 // Push the src ptr.
3547 Args.add(RValue::get(SrcVal), SrcParam.getType());
3549 // Add the rest of the default arguments.
3550 std::vector<Stmt *> ArgVec;
3551 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3552 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3553 assert(DefaultArg && "sema forgot to instantiate default args");
3554 ArgVec.push_back(DefaultArg);
3557 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3559 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3560 ConstExprIterator ArgBegin(ArgVec.data()),
3561 ArgEnd(ArgVec.data() + ArgVec.size());
3562 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3564 // Insert any ABI-specific implicit constructor arguments.
3565 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3566 /*ForVirtualBase=*/false,
3567 /*Delegating=*/false, Args);
3569 // Call the destructor with our arguments.
3570 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3571 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3572 Args, CD, Ctor_Complete, ExtraArgs);
3573 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3575 Cleanups.ForceCleanup();
3577 // Emit the ret instruction, remove any temporary instructions created for the
3579 CGF.FinishFunction(SourceLocation());
3584 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3586 int32_t VBPtrOffset,
3588 assert(!T->isReferenceType());
3590 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3591 const CXXConstructorDecl *CD =
3592 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3593 CXXCtorType CT = Ctor_Complete;
3595 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3596 CT = Ctor_CopyingClosure;
3598 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3599 SmallString<256> MangledName;
3601 llvm::raw_svector_ostream Out(MangledName);
3602 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3603 VBPtrOffset, VBIndex, Out);
3605 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3606 return getImageRelativeConstant(GV);
3608 // The TypeDescriptor is used by the runtime to determine if a catch handler
3609 // is appropriate for the exception object.
3610 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3612 // The runtime is responsible for calling the copy constructor if the
3613 // exception is caught by value.
3614 llvm::Constant *CopyCtor;
3616 if (CT == Ctor_CopyingClosure)
3617 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3619 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3621 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3623 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3625 CopyCtor = getImageRelativeConstant(CopyCtor);
3627 bool IsScalar = !RD;
3628 bool HasVirtualBases = false;
3629 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3630 QualType PointeeType = T;
3631 if (T->isPointerType())
3632 PointeeType = T->getPointeeType();
3633 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3634 HasVirtualBases = RD->getNumVBases() > 0;
3635 if (IdentifierInfo *II = RD->getIdentifier())
3636 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3639 // Encode the relevant CatchableType properties into the Flags bitfield.
3640 // FIXME: Figure out how bits 2 or 8 can get set.
3644 if (HasVirtualBases)
3649 llvm::Constant *Fields[] = {
3650 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3651 TD, // TypeDescriptor
3652 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3653 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3654 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3655 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3656 CopyCtor // CopyCtor
3658 llvm::StructType *CTType = getCatchableTypeType();
3659 auto *GV = new llvm::GlobalVariable(
3660 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3661 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3662 GV->setUnnamedAddr(true);
3663 GV->setSection(".xdata");
3664 if (GV->isWeakForLinker())
3665 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3666 return getImageRelativeConstant(GV);
3669 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3670 assert(!T->isReferenceType());
3672 // See if we've already generated a CatchableTypeArray for this type before.
3673 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3677 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3678 // using a SmallSetVector. Duplicates may arise due to virtual bases
3679 // occurring more than once in the hierarchy.
3680 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3682 // C++14 [except.handle]p3:
3683 // A handler is a match for an exception object of type E if [...]
3684 // - the handler is of type cv T or cv T& and T is an unambiguous public
3685 // base class of E, or
3686 // - the handler is of type cv T or const T& where T is a pointer type and
3687 // E is a pointer type that can be converted to T by [...]
3688 // - a standard pointer conversion (4.10) not involving conversions to
3689 // pointers to private or protected or ambiguous classes
3690 const CXXRecordDecl *MostDerivedClass = nullptr;
3691 bool IsPointer = T->isPointerType();
3693 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3695 MostDerivedClass = T->getAsCXXRecordDecl();
3697 // Collect all the unambiguous public bases of the MostDerivedClass.
3698 if (MostDerivedClass) {
3699 const ASTContext &Context = getContext();
3700 const ASTRecordLayout &MostDerivedLayout =
3701 Context.getASTRecordLayout(MostDerivedClass);
3702 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3703 SmallVector<MSRTTIClass, 8> Classes;
3704 serializeClassHierarchy(Classes, MostDerivedClass);
3705 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3706 detectAmbiguousBases(Classes);
3707 for (const MSRTTIClass &Class : Classes) {
3708 // Skip any ambiguous or private bases.
3710 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3712 // Write down how to convert from a derived pointer to a base pointer.
3713 uint32_t OffsetInVBTable = 0;
3714 int32_t VBPtrOffset = -1;
3715 if (Class.VirtualRoot) {
3717 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3718 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3721 // Turn our record back into a pointer if the exception object is a
3723 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3725 RTTITy = Context.getPointerType(RTTITy);
3726 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3727 VBPtrOffset, OffsetInVBTable));
3731 // C++14 [except.handle]p3:
3732 // A handler is a match for an exception object of type E if
3733 // - The handler is of type cv T or cv T& and E and T are the same type
3734 // (ignoring the top-level cv-qualifiers)
3735 CatchableTypes.insert(getCatchableType(T));
3737 // C++14 [except.handle]p3:
3738 // A handler is a match for an exception object of type E if
3739 // - the handler is of type cv T or const T& where T is a pointer type and
3740 // E is a pointer type that can be converted to T by [...]
3741 // - a standard pointer conversion (4.10) not involving conversions to
3742 // pointers to private or protected or ambiguous classes
3744 // C++14 [conv.ptr]p2:
3745 // A prvalue of type "pointer to cv T," where T is an object type, can be
3746 // converted to a prvalue of type "pointer to cv void".
3747 if (IsPointer && T->getPointeeType()->isObjectType())
3748 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3750 // C++14 [except.handle]p3:
3751 // A handler is a match for an exception object of type E if [...]
3752 // - the handler is of type cv T or const T& where T is a pointer or
3753 // pointer to member type and E is std::nullptr_t.
3755 // We cannot possibly list all possible pointer types here, making this
3756 // implementation incompatible with the standard. However, MSVC includes an
3757 // entry for pointer-to-void in this case. Let's do the same.
3758 if (T->isNullPtrType())
3759 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3761 uint32_t NumEntries = CatchableTypes.size();
3762 llvm::Type *CTType =
3763 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3764 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3765 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3766 llvm::Constant *Fields[] = {
3767 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3768 llvm::ConstantArray::get(
3769 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3770 CatchableTypes.end())) // CatchableTypes
3772 SmallString<256> MangledName;
3774 llvm::raw_svector_ostream Out(MangledName);
3775 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3777 CTA = new llvm::GlobalVariable(
3778 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3779 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3780 CTA->setUnnamedAddr(true);
3781 CTA->setSection(".xdata");
3782 if (CTA->isWeakForLinker())
3783 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3787 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3788 bool IsConst, IsVolatile;
3789 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
3791 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3792 // the exception object may be caught as.
3793 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3794 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3795 // This is used as a component of the mangled name which means that we need to
3796 // know what it is in order to see if we have previously generated the
3798 uint32_t NumEntries =
3799 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3800 ->getLimitedValue();
3802 SmallString<256> MangledName;
3804 llvm::raw_svector_ostream Out(MangledName);
3805 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3809 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3811 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3814 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3815 // be at least as CV qualified. Encode this requirement into the Flags
3823 // The cleanup-function (a destructor) must be called when the exception
3824 // object's lifetime ends.
3825 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3826 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3827 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3828 if (!DtorD->isTrivial())
3829 CleanupFn = llvm::ConstantExpr::getBitCast(
3830 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3832 // This is unused as far as we can tell, initialize it to null.
3833 llvm::Constant *ForwardCompat =
3834 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3835 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3836 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3837 llvm::StructType *TIType = getThrowInfoType();
3838 llvm::Constant *Fields[] = {
3839 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3840 getImageRelativeConstant(CleanupFn), // CleanupFn
3841 ForwardCompat, // ForwardCompat
3842 PointerToCatchableTypes // CatchableTypeArray
3844 auto *GV = new llvm::GlobalVariable(
3845 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3846 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3847 GV->setUnnamedAddr(true);
3848 GV->setSection(".xdata");
3849 if (GV->isWeakForLinker())
3850 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3854 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3855 const Expr *SubExpr = E->getSubExpr();
3856 QualType ThrowType = SubExpr->getType();
3857 // The exception object lives on the stack and it's address is passed to the
3858 // runtime function.
3859 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
3860 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
3863 // The so-called ThrowInfo is used to describe how the exception object may be
3865 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
3867 // Call into the runtime to throw the exception.
3868 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
3869 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);