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 "clang/AST/Decl.h"
21 #include "clang/AST/DeclCXX.h"
22 #include "clang/AST/VTableBuilder.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/StringSet.h"
25 #include "llvm/IR/CallSite.h"
27 using namespace clang;
28 using namespace CodeGen;
32 /// Holds all the vbtable globals for a given class.
33 struct VBTableGlobals {
34 const VPtrInfoVector *VBTables;
35 SmallVector<llvm::GlobalVariable *, 2> Globals;
38 class MicrosoftCXXABI : public CGCXXABI {
40 MicrosoftCXXABI(CodeGenModule &CGM)
41 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
42 ClassHierarchyDescriptorType(nullptr),
43 CompleteObjectLocatorType(nullptr) {}
45 bool HasThisReturn(GlobalDecl GD) const override;
47 bool classifyReturnType(CGFunctionInfo &FI) const override;
49 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
51 bool isSRetParameterAfterThis() const override { return true; }
53 StringRef GetPureVirtualCallName() override { return "_purecall"; }
54 // No known support for deleted functions in MSVC yet, so this choice is
56 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
58 llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF,
60 QualType type) override;
62 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
63 const VPtrInfo *Info);
65 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
67 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
68 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
69 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
71 llvm::Type *StdTypeInfoPtrTy) override;
73 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
74 QualType SrcRecordTy) override;
76 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
77 QualType SrcRecordTy, QualType DestTy,
78 QualType DestRecordTy,
79 llvm::BasicBlock *CastEnd) override;
81 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
83 QualType DestTy) override;
85 bool EmitBadCastCall(CodeGenFunction &CGF) override;
88 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
89 const CXXRecordDecl *ClassDecl,
90 const CXXRecordDecl *BaseClassDecl) override;
92 void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
93 CXXCtorType Type, CanQualType &ResTy,
94 SmallVectorImpl<CanQualType> &ArgTys) override;
97 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
98 const CXXRecordDecl *RD) override;
100 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
101 const CXXRecordDecl *RD) override;
103 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
105 // Background on MSVC destructors
106 // ==============================
108 // Both Itanium and MSVC ABIs have destructor variants. The variant names
109 // roughly correspond in the following way:
111 // Base -> no name, just ~Class
112 // Complete -> vbase destructor
113 // Deleting -> scalar deleting destructor
114 // vector deleting destructor
116 // The base and complete destructors are the same as in Itanium, although the
117 // complete destructor does not accept a VTT parameter when there are virtual
118 // bases. A separate mechanism involving vtordisps is used to ensure that
119 // virtual methods of destroyed subobjects are not called.
121 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
122 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
123 // pointer points to an array. The scalar deleting destructor assumes that
124 // bit 2 is zero, and therefore does not contain a loop.
126 // For virtual destructors, only one entry is reserved in the vftable, and it
127 // always points to the vector deleting destructor. The vector deleting
128 // destructor is the most general, so it can be used to destroy objects in
129 // place, delete single heap objects, or delete arrays.
131 // A TU defining a non-inline destructor is only guaranteed to emit a base
132 // destructor, and all of the other variants are emitted on an as-needed basis
133 // in COMDATs. Because a non-base destructor can be emitted in a TU that
134 // lacks a definition for the destructor, non-base destructors must always
135 // delegate to or alias the base destructor.
137 void BuildDestructorSignature(const CXXDestructorDecl *Dtor,
140 SmallVectorImpl<CanQualType> &ArgTys) override;
142 /// Non-base dtors should be emitted as delegating thunks in this ABI.
143 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
144 CXXDtorType DT) const override {
145 return DT != Dtor_Base;
148 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
150 const CXXRecordDecl *
151 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
152 MD = MD->getCanonicalDecl();
153 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
154 MicrosoftVTableContext::MethodVFTableLocation ML =
155 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
156 // The vbases might be ordered differently in the final overrider object
157 // and the complete object, so the "this" argument may sometimes point to
158 // memory that has no particular type (e.g. past the complete object).
159 // In this case, we just use a generic pointer type.
160 // FIXME: might want to have a more precise type in the non-virtual
161 // multiple inheritance case.
162 if (ML.VBase || !ML.VFPtrOffset.isZero())
165 return MD->getParent();
169 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
171 bool VirtualCall) override;
173 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
174 FunctionArgList &Params) override;
176 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
177 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
179 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
181 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
182 const CXXConstructorDecl *D,
183 CXXCtorType Type, bool ForVirtualBase,
185 CallArgList &Args) override;
187 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
188 CXXDtorType Type, bool ForVirtualBase,
189 bool Delegating, llvm::Value *This) override;
191 void emitVTableDefinitions(CodeGenVTables &CGVT,
192 const CXXRecordDecl *RD) override;
194 llvm::Value *getVTableAddressPointInStructor(
195 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
196 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
197 bool &NeedsVirtualOffset) override;
200 getVTableAddressPointForConstExpr(BaseSubobject Base,
201 const CXXRecordDecl *VTableClass) override;
203 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
204 CharUnits VPtrOffset) override;
206 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
208 llvm::Type *Ty) override;
210 void EmitVirtualDestructorCall(CodeGenFunction &CGF,
211 const CXXDestructorDecl *Dtor,
212 CXXDtorType DtorType, SourceLocation CallLoc,
213 llvm::Value *This) override;
215 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
216 CallArgList &CallArgs) override {
217 assert(GD.getDtorType() == Dtor_Deleting &&
218 "Only deleting destructor thunks are available in this ABI");
219 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
220 CGM.getContext().IntTy);
223 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
225 llvm::GlobalVariable *
226 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
227 llvm::GlobalVariable::LinkageTypes Linkage);
229 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
230 llvm::GlobalVariable *GV) const;
232 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
233 GlobalDecl GD, bool ReturnAdjustment) override {
234 // Never dllimport/dllexport thunks.
235 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
238 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
240 if (Linkage == GVA_Internal)
241 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
242 else if (ReturnAdjustment)
243 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
245 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
248 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
249 const ThisAdjustment &TA) override;
251 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
252 const ReturnAdjustment &RA) override;
254 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
255 llvm::GlobalVariable *DeclPtr,
256 bool PerformInit) override;
258 // ==== Notes on array cookies =========
260 // MSVC seems to only use cookies when the class has a destructor; a
261 // two-argument usual array deallocation function isn't sufficient.
263 // For example, this code prints "100" and "1":
266 // void *operator new[](size_t sz) {
267 // printf("%u\n", sz);
268 // return malloc(sz);
270 // void operator delete[](void *p, size_t sz) {
271 // printf("%u\n", sz);
276 // A *p = new A[100];
279 // Whereas it prints "104" and "104" if you give A a destructor.
281 bool requiresArrayCookie(const CXXDeleteExpr *expr,
282 QualType elementType) override;
283 bool requiresArrayCookie(const CXXNewExpr *expr) override;
284 CharUnits getArrayCookieSizeImpl(QualType type) override;
285 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
287 llvm::Value *NumElements,
288 const CXXNewExpr *expr,
289 QualType ElementType) override;
290 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
291 llvm::Value *allocPtr,
292 CharUnits cookieSize) override;
294 friend struct MSRTTIBuilder;
296 bool isImageRelative() const {
297 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
300 // 5 routines for constructing the llvm types for MS RTTI structs.
301 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
302 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
303 TDTypeName += llvm::utostr(TypeInfoString.size());
304 llvm::StructType *&TypeDescriptorType =
305 TypeDescriptorTypeMap[TypeInfoString.size()];
306 if (TypeDescriptorType)
307 return TypeDescriptorType;
308 llvm::Type *FieldTypes[] = {
311 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
313 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
314 return TypeDescriptorType;
317 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
318 if (!isImageRelative())
323 llvm::StructType *getBaseClassDescriptorType() {
324 if (BaseClassDescriptorType)
325 return BaseClassDescriptorType;
326 llvm::Type *FieldTypes[] = {
327 getImageRelativeType(CGM.Int8PtrTy),
333 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
335 BaseClassDescriptorType = llvm::StructType::create(
336 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
337 return BaseClassDescriptorType;
340 llvm::StructType *getClassHierarchyDescriptorType() {
341 if (ClassHierarchyDescriptorType)
342 return ClassHierarchyDescriptorType;
343 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
344 ClassHierarchyDescriptorType = llvm::StructType::create(
345 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
346 llvm::Type *FieldTypes[] = {
350 getImageRelativeType(
351 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
353 ClassHierarchyDescriptorType->setBody(FieldTypes);
354 return ClassHierarchyDescriptorType;
357 llvm::StructType *getCompleteObjectLocatorType() {
358 if (CompleteObjectLocatorType)
359 return CompleteObjectLocatorType;
360 CompleteObjectLocatorType = llvm::StructType::create(
361 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
362 llvm::Type *FieldTypes[] = {
366 getImageRelativeType(CGM.Int8PtrTy),
367 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
368 getImageRelativeType(CompleteObjectLocatorType),
370 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
371 if (!isImageRelative())
372 FieldTypesRef = FieldTypesRef.drop_back();
373 CompleteObjectLocatorType->setBody(FieldTypesRef);
374 return CompleteObjectLocatorType;
377 llvm::GlobalVariable *getImageBase() {
378 StringRef Name = "__ImageBase";
379 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
382 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
384 llvm::GlobalValue::ExternalLinkage,
385 /*Initializer=*/nullptr, Name);
388 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
389 if (!isImageRelative())
392 llvm::Constant *ImageBaseAsInt =
393 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
394 llvm::Constant *PtrValAsInt =
395 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
396 llvm::Constant *Diff =
397 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
398 /*HasNUW=*/true, /*HasNSW=*/true);
399 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
403 MicrosoftMangleContext &getMangleContext() {
404 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
407 llvm::Constant *getZeroInt() {
408 return llvm::ConstantInt::get(CGM.IntTy, 0);
411 llvm::Constant *getAllOnesInt() {
412 return llvm::Constant::getAllOnesValue(CGM.IntTy);
415 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
416 return C ? C : getZeroInt();
419 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
420 return C ? C : getZeroInt();
423 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
426 GetNullMemberPointerFields(const MemberPointerType *MPT,
427 llvm::SmallVectorImpl<llvm::Constant *> &fields);
429 /// \brief Shared code for virtual base adjustment. Returns the offset from
430 /// the vbptr to the virtual base. Optionally returns the address of the
432 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
434 llvm::Value *VBPtrOffset,
435 llvm::Value *VBTableOffset,
436 llvm::Value **VBPtr = nullptr);
438 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
441 int32_t VBTableOffset,
442 llvm::Value **VBPtr = nullptr) {
443 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
444 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
445 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
448 /// \brief Performs a full virtual base adjustment. Used to dereference
449 /// pointers to members of virtual bases.
450 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
451 const CXXRecordDecl *RD, llvm::Value *Base,
452 llvm::Value *VirtualBaseAdjustmentOffset,
453 llvm::Value *VBPtrOffset /* optional */);
455 /// \brief Emits a full member pointer with the fields common to data and
456 /// function member pointers.
457 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
458 bool IsMemberFunction,
459 const CXXRecordDecl *RD,
460 CharUnits NonVirtualBaseAdjustment);
462 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
463 const CXXMethodDecl *MD,
464 CharUnits NonVirtualBaseAdjustment);
466 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
469 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
470 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
472 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
473 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
475 /// \brief Generate a thunk for calling a virtual member function MD.
476 llvm::Function *EmitVirtualMemPtrThunk(
477 const CXXMethodDecl *MD,
478 const MicrosoftVTableContext::MethodVFTableLocation &ML);
481 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
483 bool isZeroInitializable(const MemberPointerType *MPT) override;
485 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
487 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
488 CharUnits offset) override;
489 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
490 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
492 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
495 const MemberPointerType *MPT,
496 bool Inequality) override;
498 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
500 const MemberPointerType *MPT) override;
503 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
504 llvm::Value *Base, llvm::Value *MemPtr,
505 const MemberPointerType *MPT) override;
507 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
509 llvm::Value *Src) override;
511 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
512 llvm::Constant *Src) override;
515 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
516 llvm::Value *&This, llvm::Value *MemPtr,
517 const MemberPointerType *MPT) override;
520 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
521 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
522 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
523 /// \brief All the vftables that have been referenced.
524 VFTablesMapTy VFTablesMap;
525 VTablesMapTy VTablesMap;
527 /// \brief This set holds the record decls we've deferred vtable emission for.
528 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
531 /// \brief All the vbtables which have been referenced.
532 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
534 /// Info on the global variable used to guard initialization of static locals.
535 /// The BitIndex field is only used for externally invisible declarations.
537 GuardInfo() : Guard(nullptr), BitIndex(0) {}
538 llvm::GlobalVariable *Guard;
542 /// Map from DeclContext to the current guard variable. We assume that the
543 /// AST is visited in source code order.
544 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
546 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
547 llvm::StructType *BaseClassDescriptorType;
548 llvm::StructType *ClassHierarchyDescriptorType;
549 llvm::StructType *CompleteObjectLocatorType;
554 CGCXXABI::RecordArgABI
555 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
556 switch (CGM.getTarget().getTriple().getArch()) {
558 // FIXME: Implement for other architectures.
561 case llvm::Triple::x86:
562 // All record arguments are passed in memory on x86. Decide whether to
563 // construct the object directly in argument memory, or to construct the
564 // argument elsewhere and copy the bytes during the call.
566 // If C++ prohibits us from making a copy, construct the arguments directly
567 // into argument memory.
568 if (!canCopyArgument(RD))
569 return RAA_DirectInMemory;
571 // Otherwise, construct the argument into a temporary and copy the bytes
572 // into the outgoing argument memory.
575 case llvm::Triple::x86_64:
576 // Win64 passes objects with non-trivial copy ctors indirectly.
577 if (RD->hasNonTrivialCopyConstructor())
580 // Win64 passes objects larger than 8 bytes indirectly.
581 if (getContext().getTypeSize(RD->getTypeForDecl()) > 64)
584 // We have a trivial copy constructor or no copy constructors, but we have
585 // to make sure it isn't deleted.
586 bool CopyDeleted = false;
587 for (const CXXConstructorDecl *CD : RD->ctors()) {
588 if (CD->isCopyConstructor()) {
589 assert(CD->isTrivial());
590 // We had at least one undeleted trivial copy ctor. Return directly.
591 if (!CD->isDeleted())
597 // The trivial copy constructor was deleted. Return indirectly.
601 // There were no copy ctors. Return in RAX.
605 llvm_unreachable("invalid enum");
608 llvm::Value *MicrosoftCXXABI::adjustToCompleteObject(CodeGenFunction &CGF,
615 /// \brief Gets the offset to the virtual base that contains the vfptr for
616 /// MS-ABI polymorphic types.
617 static llvm::Value *getPolymorphicOffset(CodeGenFunction &CGF,
618 const CXXRecordDecl *RD,
619 llvm::Value *Value) {
620 const ASTContext &Context = RD->getASTContext();
621 for (const CXXBaseSpecifier &Base : RD->vbases())
622 if (Context.getASTRecordLayout(Base.getType()->getAsCXXRecordDecl())
623 .hasExtendableVFPtr())
624 return CGF.CGM.getCXXABI().GetVirtualBaseClassOffset(
625 CGF, Value, RD, Base.getType()->getAsCXXRecordDecl());
626 llvm_unreachable("One of our vbases should be polymorphic.");
629 static std::pair<llvm::Value *, llvm::Value *>
630 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
631 QualType SrcRecordTy) {
632 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
633 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
635 if (CGF.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
636 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
638 // Perform a base adjustment.
639 llvm::Value *Offset = getPolymorphicOffset(CGF, SrcDecl, Value);
640 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
641 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
642 return std::make_pair(Value, Offset);
645 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
646 QualType SrcRecordTy) {
647 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
649 !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
652 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
653 llvm::Value *Argument) {
654 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
655 llvm::FunctionType *FTy =
656 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
657 llvm::Value *Args[] = {Argument};
658 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
659 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
662 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
663 llvm::CallSite Call =
664 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
665 Call.setDoesNotReturn();
666 CGF.Builder.CreateUnreachable();
669 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
670 QualType SrcRecordTy,
671 llvm::Value *ThisPtr,
672 llvm::Type *StdTypeInfoPtrTy) {
674 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
675 return CGF.Builder.CreateBitCast(
676 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
679 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
680 QualType SrcRecordTy) {
681 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
683 !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
686 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
687 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
688 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
689 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
691 llvm::Value *SrcRTTI =
692 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
693 llvm::Value *DestRTTI =
694 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
697 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
699 // PVOID __RTDynamicCast(
705 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
706 CGF.Int8PtrTy, CGF.Int32Ty};
707 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
708 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
710 llvm::Value *Args[] = {
711 Value, Offset, SrcRTTI, DestRTTI,
712 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
713 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
714 return CGF.Builder.CreateBitCast(Value, DestLTy);
718 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
719 QualType SrcRecordTy,
722 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
724 // PVOID __RTCastToVoid(
726 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
727 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
728 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
730 llvm::Value *Args[] = {Value};
731 return CGF.EmitRuntimeCall(Function, Args);
734 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
739 MicrosoftCXXABI::GetVirtualBaseClassOffset(CodeGenFunction &CGF,
741 const CXXRecordDecl *ClassDecl,
742 const CXXRecordDecl *BaseClassDecl) {
744 getContext().getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
745 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
746 CharUnits IntSize = getContext().getTypeSizeInChars(getContext().IntTy);
747 CharUnits VBTableChars =
749 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
750 llvm::Value *VBTableOffset =
751 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
753 llvm::Value *VBPtrToNewBase =
754 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
756 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
757 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
760 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
761 return isa<CXXConstructorDecl>(GD.getDecl());
764 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
765 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
769 if (FI.isInstanceMethod()) {
770 // If it's an instance method, aggregates are always returned indirectly via
771 // the second parameter.
772 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
773 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
775 } else if (!RD->isPOD()) {
776 // If it's a free function, non-POD types are returned indirectly.
777 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
781 // Otherwise, use the C ABI rules.
785 void MicrosoftCXXABI::BuildConstructorSignature(
786 const CXXConstructorDecl *Ctor, CXXCtorType Type, CanQualType &ResTy,
787 SmallVectorImpl<CanQualType> &ArgTys) {
789 // All parameters are already in place except is_most_derived, which goes
790 // after 'this' if it's variadic and last if it's not.
792 const CXXRecordDecl *Class = Ctor->getParent();
793 const FunctionProtoType *FPT = Ctor->getType()->castAs<FunctionProtoType>();
794 if (Class->getNumVBases()) {
795 if (FPT->isVariadic())
796 ArgTys.insert(ArgTys.begin() + 1, CGM.getContext().IntTy);
798 ArgTys.push_back(CGM.getContext().IntTy);
803 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
804 const CXXRecordDecl *RD) {
805 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
806 assert(IsMostDerivedClass &&
807 "ctor for a class with virtual bases must have an implicit parameter");
808 llvm::Value *IsCompleteObject =
809 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
811 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
812 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
813 CGF.Builder.CreateCondBr(IsCompleteObject,
814 CallVbaseCtorsBB, SkipVbaseCtorsBB);
816 CGF.EmitBlock(CallVbaseCtorsBB);
818 // Fill in the vbtable pointers here.
819 EmitVBPtrStores(CGF, RD);
821 // CGF will put the base ctor calls in this basic block for us later.
823 return SkipVbaseCtorsBB;
826 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
827 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
828 // In most cases, an override for a vbase virtual method can adjust
829 // the "this" parameter by applying a constant offset.
830 // However, this is not enough while a constructor or a destructor of some
831 // class X is being executed if all the following conditions are met:
832 // - X has virtual bases, (1)
833 // - X overrides a virtual method M of a vbase Y, (2)
834 // - X itself is a vbase of the most derived class.
836 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
837 // which holds the extra amount of "this" adjustment we must do when we use
838 // the X vftables (i.e. during X ctor or dtor).
839 // Outside the ctors and dtors, the values of vtorDisps are zero.
841 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
842 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
843 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
844 CGBuilderTy &Builder = CGF.Builder;
847 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
848 llvm::Value *Int8This = nullptr; // Initialize lazily.
850 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
852 if (!I->second.hasVtorDisp())
855 llvm::Value *VBaseOffset =
856 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
857 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
858 // just to Trunc back immediately.
859 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
860 uint64_t ConstantVBaseOffset =
861 Layout.getVBaseClassOffset(I->first).getQuantity();
863 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
864 llvm::Value *VtorDispValue = Builder.CreateSub(
865 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
869 Int8This = Builder.CreateBitCast(getThisValue(CGF),
870 CGF.Int8Ty->getPointerTo(AS));
871 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
872 // vtorDisp is always the 32-bits before the vbase in the class layout.
873 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
874 VtorDispPtr = Builder.CreateBitCast(
875 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
877 Builder.CreateStore(VtorDispValue, VtorDispPtr);
881 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
882 // There's only one constructor type in this ABI.
883 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
886 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
887 const CXXRecordDecl *RD) {
888 llvm::Value *ThisInt8Ptr =
889 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
890 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
892 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
893 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
894 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
895 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
896 const ASTRecordLayout &SubobjectLayout =
897 CGM.getContext().getASTRecordLayout(VBT->BaseWithVPtr);
898 CharUnits Offs = VBT->NonVirtualOffset;
899 Offs += SubobjectLayout.getVBPtrOffset();
900 if (VBT->getVBaseWithVPtr())
901 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
903 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
904 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GV->getType()->getPointerTo(0),
905 "vbptr." + VBT->ReusingBase->getName());
906 CGF.Builder.CreateStore(GV, VBPtr);
910 void MicrosoftCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor,
913 SmallVectorImpl<CanQualType> &ArgTys) {
914 // 'this' is already in place
916 // TODO: 'for base' flag
918 if (Type == Dtor_Deleting) {
919 // The scalar deleting destructor takes an implicit int parameter.
920 ArgTys.push_back(CGM.getContext().IntTy);
924 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
925 // The TU defining a dtor is only guaranteed to emit a base destructor. All
926 // other destructor variants are delegating thunks.
927 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
931 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
932 GD = GD.getCanonicalDecl();
933 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
935 GlobalDecl LookupGD = GD;
936 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
937 // Complete destructors take a pointer to the complete object as a
938 // parameter, thus don't need this adjustment.
939 if (GD.getDtorType() == Dtor_Complete)
942 // There's no Dtor_Base in vftable but it shares the this adjustment with
943 // the deleting one, so look it up instead.
944 LookupGD = GlobalDecl(DD, Dtor_Deleting);
947 MicrosoftVTableContext::MethodVFTableLocation ML =
948 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
949 CharUnits Adjustment = ML.VFPtrOffset;
951 // Normal virtual instance methods need to adjust from the vfptr that first
952 // defined the virtual method to the virtual base subobject, but destructors
953 // do not. The vector deleting destructor thunk applies this adjustment for
955 if (isa<CXXDestructorDecl>(MD))
956 Adjustment = CharUnits::Zero();
959 const ASTRecordLayout &DerivedLayout =
960 CGM.getContext().getASTRecordLayout(MD->getParent());
961 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
967 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
968 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
970 // If the call of a virtual function is not virtual, we just have to
971 // compensate for the adjustment the virtual function does in its prologue.
972 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
973 if (Adjustment.isZero())
976 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
977 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
978 This = CGF.Builder.CreateBitCast(This, charPtrTy);
979 assert(Adjustment.isPositive());
980 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
983 GD = GD.getCanonicalDecl();
984 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
986 GlobalDecl LookupGD = GD;
987 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
988 // Complete dtors take a pointer to the complete object,
989 // thus don't need adjustment.
990 if (GD.getDtorType() == Dtor_Complete)
993 // There's only Dtor_Deleting in vftable but it shares the this adjustment
994 // with the base one, so look up the deleting one instead.
995 LookupGD = GlobalDecl(DD, Dtor_Deleting);
997 MicrosoftVTableContext::MethodVFTableLocation ML =
998 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1000 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1001 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1002 CharUnits StaticOffset = ML.VFPtrOffset;
1004 // Base destructors expect 'this' to point to the beginning of the base
1005 // subobject, not the first vfptr that happens to contain the virtual dtor.
1006 // However, we still need to apply the virtual base adjustment.
1007 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1008 StaticOffset = CharUnits::Zero();
1011 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1012 llvm::Value *VBaseOffset =
1013 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1014 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1016 if (!StaticOffset.isZero()) {
1017 assert(StaticOffset.isPositive());
1018 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1020 // Non-virtual adjustment might result in a pointer outside the allocated
1021 // object, e.g. if the final overrider class is laid out after the virtual
1022 // base that declares a method in the most derived class.
1023 // FIXME: Update the code that emits this adjustment in thunks prologues.
1024 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1026 This = CGF.Builder.CreateConstInBoundsGEP1_32(This,
1027 StaticOffset.getQuantity());
1033 static bool IsDeletingDtor(GlobalDecl GD) {
1034 const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl());
1035 if (isa<CXXDestructorDecl>(MD)) {
1036 return GD.getDtorType() == Dtor_Deleting;
1041 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1043 FunctionArgList &Params) {
1044 ASTContext &Context = getContext();
1045 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1046 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1047 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1048 ImplicitParamDecl *IsMostDerived
1049 = ImplicitParamDecl::Create(Context, nullptr,
1050 CGF.CurGD.getDecl()->getLocation(),
1051 &Context.Idents.get("is_most_derived"),
1053 // The 'most_derived' parameter goes second if the ctor is variadic and last
1054 // if it's not. Dtors can't be variadic.
1055 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1056 if (FPT->isVariadic())
1057 Params.insert(Params.begin() + 1, IsMostDerived);
1059 Params.push_back(IsMostDerived);
1060 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1061 } else if (IsDeletingDtor(CGF.CurGD)) {
1062 ImplicitParamDecl *ShouldDelete
1063 = ImplicitParamDecl::Create(Context, nullptr,
1064 CGF.CurGD.getDecl()->getLocation(),
1065 &Context.Idents.get("should_call_delete"),
1067 Params.push_back(ShouldDelete);
1068 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1072 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1073 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1074 // In this ABI, every virtual function takes a pointer to one of the
1075 // subobjects that first defines it as the 'this' parameter, rather than a
1076 // pointer to the final overrider subobject. Thus, we need to adjust it back
1077 // to the final overrider subobject before use.
1078 // See comments in the MicrosoftVFTableContext implementation for the details.
1079 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1080 if (Adjustment.isZero())
1083 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1084 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1085 *thisTy = This->getType();
1087 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1088 assert(Adjustment.isPositive());
1090 CGF.Builder.CreateConstInBoundsGEP1_32(This, -Adjustment.getQuantity());
1091 return CGF.Builder.CreateBitCast(This, thisTy);
1094 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1097 /// If this is a function that the ABI specifies returns 'this', initialize
1098 /// the return slot to 'this' at the start of the function.
1100 /// Unlike the setting of return types, this is done within the ABI
1101 /// implementation instead of by clients of CGCXXABI because:
1102 /// 1) getThisValue is currently protected
1103 /// 2) in theory, an ABI could implement 'this' returns some other way;
1104 /// HasThisReturn only specifies a contract, not the implementation
1105 if (HasThisReturn(CGF.CurGD))
1106 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1108 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1109 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1110 assert(getStructorImplicitParamDecl(CGF) &&
1111 "no implicit parameter for a constructor with virtual bases?");
1112 getStructorImplicitParamValue(CGF)
1113 = CGF.Builder.CreateLoad(
1114 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1118 if (IsDeletingDtor(CGF.CurGD)) {
1119 assert(getStructorImplicitParamDecl(CGF) &&
1120 "no implicit parameter for a deleting destructor?");
1121 getStructorImplicitParamValue(CGF)
1122 = CGF.Builder.CreateLoad(
1123 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1124 "should_call_delete");
1128 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1129 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1130 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1131 assert(Type == Ctor_Complete || Type == Ctor_Base);
1133 // Check if we need a 'most_derived' parameter.
1134 if (!D->getParent()->getNumVBases())
1137 // Add the 'most_derived' argument second if we are variadic or last if not.
1138 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1139 llvm::Value *MostDerivedArg =
1140 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1141 RValue RV = RValue::get(MostDerivedArg);
1142 if (MostDerivedArg) {
1143 if (FPT->isVariadic())
1144 Args.insert(Args.begin() + 1,
1145 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1147 Args.add(RV, getContext().IntTy);
1150 return 1; // Added one arg.
1153 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1154 const CXXDestructorDecl *DD,
1155 CXXDtorType Type, bool ForVirtualBase,
1156 bool Delegating, llvm::Value *This) {
1157 llvm::Value *Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
1159 if (DD->isVirtual()) {
1160 assert(Type != CXXDtorType::Dtor_Deleting &&
1161 "The deleting destructor should only be called via a virtual call");
1162 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1166 // FIXME: Provide a source location here.
1167 CGF.EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This,
1168 /*ImplicitParam=*/nullptr,
1169 /*ImplicitParamTy=*/QualType(), nullptr, nullptr);
1172 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1173 const CXXRecordDecl *RD) {
1174 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1175 VPtrInfoVector VFPtrs = VFTContext.getVFPtrOffsets(RD);
1177 for (VPtrInfo *Info : VFPtrs) {
1178 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1179 if (VTable->hasInitializer())
1182 llvm::Constant *RTTI = getMSCompleteObjectLocator(RD, Info);
1184 const VTableLayout &VTLayout =
1185 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1186 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1187 RD, VTLayout.vtable_component_begin(),
1188 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1189 VTLayout.getNumVTableThunks(), RTTI);
1191 VTable->setInitializer(Init);
1195 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1196 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1197 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1198 NeedsVirtualOffset = (NearestVBase != nullptr);
1200 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1201 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1202 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1203 if (!VTableAddressPoint) {
1204 assert(Base.getBase()->getNumVBases() &&
1205 !CGM.getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1207 return VTableAddressPoint;
1210 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1211 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1212 SmallString<256> &Name) {
1213 llvm::raw_svector_ostream Out(Name);
1214 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1217 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1218 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1219 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1220 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1221 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1222 assert(VFTable && "Couldn't find a vftable for the given base?");
1226 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1227 CharUnits VPtrOffset) {
1228 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1229 // shouldn't be used in the given record type. We want to cache this result in
1230 // VFTablesMap, thus a simple zero check is not sufficient.
1231 VFTableIdTy ID(RD, VPtrOffset);
1232 VTablesMapTy::iterator I;
1234 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1238 llvm::GlobalVariable *&VTable = I->second;
1240 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1241 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1243 if (DeferredVFTables.insert(RD)) {
1244 // We haven't processed this record type before.
1245 // Queue up this v-table for possible deferred emission.
1246 CGM.addDeferredVTable(RD);
1249 // Create all the vftables at once in order to make sure each vftable has
1250 // a unique mangled name.
1251 llvm::StringSet<> ObservedMangledNames;
1252 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1253 SmallString<256> Name;
1254 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1255 if (!ObservedMangledNames.insert(Name.str()))
1256 llvm_unreachable("Already saw this mangling before?");
1261 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1262 if (VFPtrs[J]->FullOffsetInMDC != VPtrOffset)
1264 SmallString<256> VFTableName;
1265 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], VFTableName);
1266 StringRef VTableName = VFTableName;
1268 uint64_t NumVTableSlots =
1269 VTContext.getVFTableLayout(RD, VFPtrs[J]->FullOffsetInMDC)
1270 .getNumVTableComponents();
1271 llvm::GlobalValue::LinkageTypes VTableLinkage =
1272 llvm::GlobalValue::ExternalLinkage;
1273 llvm::ArrayType *VTableType =
1274 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1275 if (getContext().getLangOpts().RTTIData) {
1276 VTableLinkage = llvm::GlobalValue::PrivateLinkage;
1280 VTable = CGM.getModule().getNamedGlobal(VFTableName);
1282 // Create a backing variable for the contents of VTable. The VTable may
1283 // or may not include space for a pointer to RTTI data.
1284 llvm::GlobalValue *VFTable = VTable = new llvm::GlobalVariable(
1285 CGM.getModule(), VTableType, /*isConstant=*/true, VTableLinkage,
1286 /*Initializer=*/nullptr, VTableName);
1287 VTable->setUnnamedAddr(true);
1289 // Only insert a pointer into the VFTable for RTTI data if we are not
1290 // importing it. We never reference the RTTI data directly so there is no
1291 // need to make room for it.
1292 if (getContext().getLangOpts().RTTIData &&
1293 !RD->hasAttr<DLLImportAttr>()) {
1294 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1295 llvm::ConstantInt::get(CGM.IntTy, 1)};
1296 // Create a GEP which points just after the first entry in the VFTable,
1297 // this should be the location of the first virtual method.
1298 llvm::Constant *VTableGEP =
1299 llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, GEPIndices);
1300 // The symbol for the VFTable is an alias to the GEP. It is
1301 // transparent, to other modules, what the nature of this symbol is; all
1302 // that matters is that the alias be the address of the first virtual
1304 VFTable = llvm::GlobalAlias::create(
1305 cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(),
1306 /*AddressSpace=*/0, llvm::GlobalValue::ExternalLinkage,
1307 VFTableName.str(), VTableGEP, &CGM.getModule());
1309 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1310 // be referencing any RTTI data. The GlobalVariable will end up being
1311 // an appropriate definition of the VFTable.
1312 VTable->setName(VFTableName.str());
1315 VFTable->setUnnamedAddr(true);
1316 if (RD->hasAttr<DLLImportAttr>())
1317 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1318 else if (RD->hasAttr<DLLExportAttr>())
1319 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1321 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1322 if (VFTable != VTable) {
1323 if (llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage)) {
1324 // AvailableExternally implies that we grabbed the data from another
1325 // executable. No need to stick the alias in a Comdat.
1326 } else if (llvm::GlobalValue::isInternalLinkage(VFTableLinkage) ||
1327 llvm::GlobalValue::isWeakODRLinkage(VFTableLinkage) ||
1328 llvm::GlobalValue::isLinkOnceODRLinkage(VFTableLinkage)) {
1329 // The alias is going to be dropped into a Comdat, no need to make it
1331 if (!llvm::GlobalValue::isInternalLinkage(VFTableLinkage))
1332 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1334 CGM.getModule().getOrInsertComdat(VFTable->getName());
1335 // We must indicate which VFTable is larger to support linking between
1336 // translation units which do and do not have RTTI data. The largest
1337 // VFTable contains the RTTI data; translation units which reference
1338 // the smaller VFTable always reference it relative to the first
1340 C->setSelectionKind(llvm::Comdat::Largest);
1341 VTable->setComdat(C);
1343 llvm_unreachable("unexpected linkage for vftable!");
1346 VFTable->setLinkage(VFTableLinkage);
1347 CGM.setGlobalVisibility(VFTable, RD);
1348 VFTablesMap[ID] = VFTable;
1356 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1360 GD = GD.getCanonicalDecl();
1361 CGBuilderTy &Builder = CGF.Builder;
1363 Ty = Ty->getPointerTo()->getPointerTo();
1365 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1366 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1368 MicrosoftVTableContext::MethodVFTableLocation ML =
1369 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1370 llvm::Value *VFuncPtr =
1371 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1372 return Builder.CreateLoad(VFuncPtr);
1375 void MicrosoftCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF,
1376 const CXXDestructorDecl *Dtor,
1377 CXXDtorType DtorType,
1378 SourceLocation CallLoc,
1379 llvm::Value *This) {
1380 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1382 // We have only one destructor in the vftable but can get both behaviors
1383 // by passing an implicit int parameter.
1384 GlobalDecl GD(Dtor, Dtor_Deleting);
1385 const CGFunctionInfo *FInfo =
1386 &CGM.getTypes().arrangeCXXDestructor(Dtor, Dtor_Deleting);
1387 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1388 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1390 ASTContext &Context = CGF.getContext();
1391 llvm::Value *ImplicitParam =
1392 llvm::ConstantInt::get(llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1393 DtorType == Dtor_Deleting);
1395 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1396 CGF.EmitCXXMemberCall(Dtor, CallLoc, Callee, ReturnValueSlot(), This,
1397 ImplicitParam, Context.IntTy, nullptr, nullptr);
1400 const VBTableGlobals &
1401 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1402 // At this layer, we can key the cache off of a single class, which is much
1403 // easier than caching each vbtable individually.
1404 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1406 std::tie(Entry, Added) =
1407 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1408 VBTableGlobals &VBGlobals = Entry->second;
1412 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1413 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1415 // Cache the globals for all vbtables so we don't have to recompute the
1417 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1418 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1419 E = VBGlobals.VBTables->end();
1421 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1427 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1428 const CXXMethodDecl *MD,
1429 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1430 // Calculate the mangled name.
1431 SmallString<256> ThunkName;
1432 llvm::raw_svector_ostream Out(ThunkName);
1433 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1436 // If the thunk has been generated previously, just return it.
1437 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1438 return cast<llvm::Function>(GV);
1440 // Create the llvm::Function.
1441 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeGlobalDeclaration(MD);
1442 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1443 llvm::Function *ThunkFn =
1444 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1445 ThunkName.str(), &CGM.getModule());
1446 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1448 ThunkFn->setLinkage(MD->isExternallyVisible()
1449 ? llvm::GlobalValue::LinkOnceODRLinkage
1450 : llvm::GlobalValue::InternalLinkage);
1452 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1453 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1456 CodeGenFunction CGF(CGM);
1457 CGF.StartThunk(ThunkFn, MD, FnInfo);
1459 // Load the vfptr and then callee from the vftable. The callee should have
1460 // adjusted 'this' so that the vfptr is at offset zero.
1461 llvm::Value *This = CGF.LoadCXXThis();
1462 llvm::Value *VTable =
1463 CGF.GetVTablePtr(This, ThunkTy->getPointerTo()->getPointerTo());
1464 llvm::Value *VFuncPtr =
1465 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1466 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1468 unsigned CallingConv;
1469 CodeGen::AttributeListType AttributeList;
1470 CGM.ConstructAttributeList(FnInfo, MD, AttributeList, CallingConv, true);
1471 llvm::AttributeSet Attrs =
1472 llvm::AttributeSet::get(CGF.getLLVMContext(), AttributeList);
1474 // Do a musttail call with perfect argument forwarding. Any inalloca argument
1475 // will be forwarded in place without any copy.
1476 SmallVector<llvm::Value *, 8> Args;
1477 for (llvm::Argument &A : ThunkFn->args())
1479 llvm::CallInst *Call = CGF.Builder.CreateCall(Callee, Args);
1480 Call->setTailCallKind(llvm::CallInst::TCK_MustTail);
1481 Call->setAttributes(Attrs);
1482 Call->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
1484 if (Call->getType()->isVoidTy())
1485 CGF.Builder.CreateRetVoid();
1487 CGF.Builder.CreateRet(Call);
1489 // Finish the function to maintain CodeGenFunction invariants.
1490 // FIXME: Don't emit unreachable code.
1491 CGF.EmitBlock(CGF.createBasicBlock());
1492 CGF.FinishFunction();
1497 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1498 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1499 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1500 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1501 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1502 emitVBTableDefinition(*VBT, RD, GV);
1506 llvm::GlobalVariable *
1507 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1508 llvm::GlobalVariable::LinkageTypes Linkage) {
1509 SmallString<256> OutName;
1510 llvm::raw_svector_ostream Out(OutName);
1511 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1513 StringRef Name = OutName.str();
1515 llvm::ArrayType *VBTableType =
1516 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1518 assert(!CGM.getModule().getNamedGlobal(Name) &&
1519 "vbtable with this name already exists: mangling bug?");
1520 llvm::GlobalVariable *GV =
1521 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1522 GV->setUnnamedAddr(true);
1524 if (RD->hasAttr<DLLImportAttr>())
1525 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1526 else if (RD->hasAttr<DLLExportAttr>())
1527 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1532 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1533 const CXXRecordDecl *RD,
1534 llvm::GlobalVariable *GV) const {
1535 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1537 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1538 "should only emit vbtables for classes with vbtables");
1540 const ASTRecordLayout &BaseLayout =
1541 CGM.getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1542 const ASTRecordLayout &DerivedLayout =
1543 CGM.getContext().getASTRecordLayout(RD);
1545 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1548 // The offset from ReusingBase's vbptr to itself always leads.
1549 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1550 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1552 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1553 for (const auto &I : ReusingBase->vbases()) {
1554 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1555 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1556 assert(!Offset.isNegative());
1558 // Make it relative to the subobject vbptr.
1559 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1560 if (VBT.getVBaseWithVPtr())
1561 CompleteVBPtrOffset +=
1562 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1563 Offset -= CompleteVBPtrOffset;
1565 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1566 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1567 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1570 assert(Offsets.size() ==
1571 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1572 ->getElementType())->getNumElements());
1573 llvm::ArrayType *VBTableType =
1574 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1575 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1576 GV->setInitializer(Init);
1578 // Set the right visibility.
1579 CGM.setGlobalVisibility(GV, RD);
1582 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1584 const ThisAdjustment &TA) {
1588 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1590 if (!TA.Virtual.isEmpty()) {
1591 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1592 // Adjust the this argument based on the vtordisp value.
1593 llvm::Value *VtorDispPtr =
1594 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1596 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1597 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1598 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1600 if (TA.Virtual.Microsoft.VBPtrOffset) {
1601 // If the final overrider is defined in a virtual base other than the one
1602 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1603 // the vbtable of the derived class.
1604 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1605 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1607 llvm::Value *VBaseOffset =
1608 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1609 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1610 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1614 if (TA.NonVirtual) {
1615 // Non-virtual adjustment might result in a pointer outside the allocated
1616 // object, e.g. if the final overrider class is laid out after the virtual
1617 // base that declares a method in the most derived class.
1618 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1621 // Don't need to bitcast back, the call CodeGen will handle this.
1626 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1627 const ReturnAdjustment &RA) {
1631 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1633 if (RA.Virtual.Microsoft.VBIndex) {
1634 assert(RA.Virtual.Microsoft.VBIndex > 0);
1636 getContext().getTypeSizeInChars(getContext().IntTy).getQuantity();
1638 llvm::Value *VBaseOffset =
1639 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1640 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1641 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1645 V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual);
1647 // Cast back to the original type.
1648 return CGF.Builder.CreateBitCast(V, Ret->getType());
1651 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1652 QualType elementType) {
1653 // Microsoft seems to completely ignore the possibility of a
1654 // two-argument usual deallocation function.
1655 return elementType.isDestructedType();
1658 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1659 // Microsoft seems to completely ignore the possibility of a
1660 // two-argument usual deallocation function.
1661 return expr->getAllocatedType().isDestructedType();
1664 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1665 // The array cookie is always a size_t; we then pad that out to the
1666 // alignment of the element type.
1667 ASTContext &Ctx = getContext();
1668 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1669 Ctx.getTypeAlignInChars(type));
1672 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1673 llvm::Value *allocPtr,
1674 CharUnits cookieSize) {
1675 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1676 llvm::Value *numElementsPtr =
1677 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1678 return CGF.Builder.CreateLoad(numElementsPtr);
1681 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1682 llvm::Value *newPtr,
1683 llvm::Value *numElements,
1684 const CXXNewExpr *expr,
1685 QualType elementType) {
1686 assert(requiresArrayCookie(expr));
1688 // The size of the cookie.
1689 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1691 // Compute an offset to the cookie.
1692 llvm::Value *cookiePtr = newPtr;
1694 // Write the number of elements into the appropriate slot.
1695 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1696 llvm::Value *numElementsPtr
1697 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1698 CGF.Builder.CreateStore(numElements, numElementsPtr);
1700 // Finally, compute a pointer to the actual data buffer by skipping
1701 // over the cookie completely.
1702 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1703 cookieSize.getQuantity());
1706 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
1707 llvm::GlobalVariable *GV,
1709 // MSVC only uses guards for static locals.
1710 if (!D.isStaticLocal()) {
1711 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
1712 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
1713 CGF.CurFn->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
1714 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
1718 // MSVC always uses an i32 bitfield to guard initialization, which is *not*
1719 // threadsafe. Since the user may be linking in inline functions compiled by
1720 // cl.exe, there's no reason to provide a false sense of security by using
1721 // critical sections here.
1724 CGM.ErrorUnsupported(&D, "dynamic TLS initialization");
1726 CGBuilderTy &Builder = CGF.Builder;
1727 llvm::IntegerType *GuardTy = CGF.Int32Ty;
1728 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
1730 // Get the guard variable for this function if we have one already.
1731 GuardInfo *GI = &GuardVariableMap[D.getDeclContext()];
1734 if (D.isStaticLocal() && D.isExternallyVisible()) {
1735 // Externally visible variables have to be numbered in Sema to properly
1736 // handle unreachable VarDecls.
1737 BitIndex = getContext().getStaticLocalNumber(&D);
1738 assert(BitIndex > 0);
1741 // Non-externally visible variables are numbered here in CodeGen.
1742 BitIndex = GI->BitIndex++;
1745 if (BitIndex >= 32) {
1746 if (D.isExternallyVisible())
1747 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
1749 GI->Guard = nullptr;
1752 // Lazily create the i32 bitfield for this function.
1754 // Mangle the name for the guard.
1755 SmallString<256> GuardName;
1757 llvm::raw_svector_ostream Out(GuardName);
1758 getMangleContext().mangleStaticGuardVariable(&D, Out);
1762 // Create the guard variable with a zero-initializer. Just absorb linkage,
1763 // visibility and dll storage class from the guarded variable.
1765 new llvm::GlobalVariable(CGM.getModule(), GuardTy, false,
1766 GV->getLinkage(), Zero, GuardName.str());
1767 GI->Guard->setVisibility(GV->getVisibility());
1768 GI->Guard->setDLLStorageClass(GV->getDLLStorageClass());
1770 assert(GI->Guard->getLinkage() == GV->getLinkage() &&
1771 "static local from the same function had different linkage");
1774 // Pseudo code for the test:
1775 // if (!(GuardVar & MyGuardBit)) {
1776 // GuardVar |= MyGuardBit;
1777 // ... initialize the object ...;
1780 // Test our bit from the guard variable.
1781 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << BitIndex);
1782 llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard);
1783 llvm::Value *IsInitialized =
1784 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
1785 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
1786 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
1787 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
1789 // Set our bit in the guard variable and emit the initializer and add a global
1790 // destructor if appropriate.
1791 CGF.EmitBlock(InitBlock);
1792 Builder.CreateStore(Builder.CreateOr(LI, Bit), GI->Guard);
1793 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
1794 Builder.CreateBr(EndBlock);
1797 CGF.EmitBlock(EndBlock);
1800 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
1801 // Null-ness for function memptrs only depends on the first field, which is
1802 // the function pointer. The rest don't matter, so we can zero initialize.
1803 if (MPT->isMemberFunctionPointer())
1806 // The virtual base adjustment field is always -1 for null, so if we have one
1807 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
1808 // valid field offset.
1809 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
1810 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
1811 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
1812 RD->nullFieldOffsetIsZero());
1816 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
1817 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
1818 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
1819 llvm::SmallVector<llvm::Type *, 4> fields;
1820 if (MPT->isMemberFunctionPointer())
1821 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
1823 fields.push_back(CGM.IntTy); // FieldOffset
1825 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
1827 fields.push_back(CGM.IntTy);
1828 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
1829 fields.push_back(CGM.IntTy);
1830 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
1831 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
1833 if (fields.size() == 1)
1835 return llvm::StructType::get(CGM.getLLVMContext(), fields);
1838 void MicrosoftCXXABI::
1839 GetNullMemberPointerFields(const MemberPointerType *MPT,
1840 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
1841 assert(fields.empty());
1842 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
1843 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
1844 if (MPT->isMemberFunctionPointer()) {
1845 // FunctionPointerOrVirtualThunk
1846 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
1848 if (RD->nullFieldOffsetIsZero())
1849 fields.push_back(getZeroInt()); // FieldOffset
1851 fields.push_back(getAllOnesInt()); // FieldOffset
1854 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
1856 fields.push_back(getZeroInt());
1857 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
1858 fields.push_back(getZeroInt());
1859 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
1860 fields.push_back(getAllOnesInt());
1864 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
1865 llvm::SmallVector<llvm::Constant *, 4> fields;
1866 GetNullMemberPointerFields(MPT, fields);
1867 if (fields.size() == 1)
1869 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
1870 assert(Res->getType() == ConvertMemberPointerType(MPT));
1875 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
1876 bool IsMemberFunction,
1877 const CXXRecordDecl *RD,
1878 CharUnits NonVirtualBaseAdjustment)
1880 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
1882 // Single inheritance class member pointer are represented as scalars instead
1884 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
1887 llvm::SmallVector<llvm::Constant *, 4> fields;
1888 fields.push_back(FirstField);
1890 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
1891 fields.push_back(llvm::ConstantInt::get(
1892 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
1894 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
1895 CharUnits Offs = CharUnits::Zero();
1896 if (RD->getNumVBases())
1897 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
1898 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
1901 // The rest of the fields are adjusted by conversions to a more derived class.
1902 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
1903 fields.push_back(getZeroInt());
1905 return llvm::ConstantStruct::getAnon(fields);
1909 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
1911 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
1912 llvm::Constant *FirstField =
1913 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
1914 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
1918 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
1919 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
1922 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
1924 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
1925 const ValueDecl *MPD = MP.getMemberPointerDecl();
1927 return EmitNullMemberPointer(MPT);
1929 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
1931 // FIXME PR15713: Support virtual inheritance paths.
1933 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
1934 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
1937 CharUnits FieldOffset =
1938 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
1939 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
1943 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
1944 const CXXMethodDecl *MD,
1945 CharUnits NonVirtualBaseAdjustment) {
1946 assert(MD->isInstance() && "Member function must not be static!");
1947 MD = MD->getCanonicalDecl();
1948 RD = RD->getMostRecentDecl();
1949 CodeGenTypes &Types = CGM.getTypes();
1951 llvm::Constant *FirstField;
1952 if (!MD->isVirtual()) {
1953 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1955 // Check whether the function has a computable LLVM signature.
1956 if (Types.isFuncTypeConvertible(FPT)) {
1957 // The function has a computable LLVM signature; use the correct type.
1958 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
1960 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
1961 // function type is incomplete.
1964 FirstField = CGM.GetAddrOfFunction(MD, Ty);
1965 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
1967 MicrosoftVTableContext::MethodVFTableLocation ML =
1968 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
1969 if (MD->isVariadic()) {
1970 CGM.ErrorUnsupported(MD, "pointer to variadic virtual member function");
1971 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
1972 } else if (!CGM.getTypes().isFuncTypeConvertible(
1973 MD->getType()->castAs<FunctionType>())) {
1974 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
1975 "incomplete return or parameter type");
1976 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
1977 } else if (ML.VBase) {
1978 CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding "
1979 "member function in virtual base class");
1980 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
1982 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
1983 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
1984 // Include the vfptr adjustment if the method is in a non-primary vftable.
1985 NonVirtualBaseAdjustment += ML.VFPtrOffset;
1989 // The rest of the fields are common with data member pointers.
1990 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
1991 NonVirtualBaseAdjustment);
1994 /// Member pointers are the same if they're either bitwise identical *or* both
1995 /// null. Null-ness for function members is determined by the first field,
1996 /// while for data member pointers we must compare all fields.
1998 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2001 const MemberPointerType *MPT,
2003 CGBuilderTy &Builder = CGF.Builder;
2005 // Handle != comparisons by switching the sense of all boolean operations.
2006 llvm::ICmpInst::Predicate Eq;
2007 llvm::Instruction::BinaryOps And, Or;
2009 Eq = llvm::ICmpInst::ICMP_NE;
2010 And = llvm::Instruction::Or;
2011 Or = llvm::Instruction::And;
2013 Eq = llvm::ICmpInst::ICMP_EQ;
2014 And = llvm::Instruction::And;
2015 Or = llvm::Instruction::Or;
2018 // If this is a single field member pointer (single inheritance), this is a
2020 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2021 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2022 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2024 return Builder.CreateICmp(Eq, L, R);
2026 // Compare the first field.
2027 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2028 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2029 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2031 // Compare everything other than the first field.
2032 llvm::Value *Res = nullptr;
2033 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2034 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2035 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2036 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2037 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2039 Res = Builder.CreateBinOp(And, Res, Cmp);
2044 // Check if the first field is 0 if this is a function pointer.
2045 if (MPT->isMemberFunctionPointer()) {
2046 // (l1 == r1 && ...) || l0 == 0
2047 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2048 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2049 Res = Builder.CreateBinOp(Or, Res, IsZero);
2052 // Combine the comparison of the first field, which must always be true for
2053 // this comparison to succeeed.
2054 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2058 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2059 llvm::Value *MemPtr,
2060 const MemberPointerType *MPT) {
2061 CGBuilderTy &Builder = CGF.Builder;
2062 llvm::SmallVector<llvm::Constant *, 4> fields;
2063 // We only need one field for member functions.
2064 if (MPT->isMemberFunctionPointer())
2065 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2067 GetNullMemberPointerFields(MPT, fields);
2068 assert(!fields.empty());
2069 llvm::Value *FirstField = MemPtr;
2070 if (MemPtr->getType()->isStructTy())
2071 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2072 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2074 // For function member pointers, we only need to test the function pointer
2075 // field. The other fields if any can be garbage.
2076 if (MPT->isMemberFunctionPointer())
2079 // Otherwise, emit a series of compares and combine the results.
2080 for (int I = 1, E = fields.size(); I < E; ++I) {
2081 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2082 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2083 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2088 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2089 llvm::Constant *Val) {
2090 // Function pointers are null if the pointer in the first field is null.
2091 if (MPT->isMemberFunctionPointer()) {
2092 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2093 Val->getAggregateElement(0U) : Val;
2094 return FirstField->isNullValue();
2097 // If it's not a function pointer and it's zero initializable, we can easily
2099 if (isZeroInitializable(MPT) && Val->isNullValue())
2102 // Otherwise, break down all the fields for comparison. Hopefully these
2103 // little Constants are reused, while a big null struct might not be.
2104 llvm::SmallVector<llvm::Constant *, 4> Fields;
2105 GetNullMemberPointerFields(MPT, Fields);
2106 if (Fields.size() == 1) {
2107 assert(Val->getType()->isIntegerTy());
2108 return Val == Fields[0];
2112 for (I = 0, E = Fields.size(); I != E; ++I) {
2113 if (Val->getAggregateElement(I) != Fields[I])
2120 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2122 llvm::Value *VBPtrOffset,
2123 llvm::Value *VBTableOffset,
2124 llvm::Value **VBPtrOut) {
2125 CGBuilderTy &Builder = CGF.Builder;
2126 // Load the vbtable pointer from the vbptr in the instance.
2127 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2128 llvm::Value *VBPtr =
2129 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2130 if (VBPtrOut) *VBPtrOut = VBPtr;
2131 VBPtr = Builder.CreateBitCast(VBPtr, CGM.Int8PtrTy->getPointerTo(0));
2132 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2134 // Load an i32 offset from the vb-table.
2135 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableOffset);
2136 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2137 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2140 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2142 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2143 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2144 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2145 CGBuilderTy &Builder = CGF.Builder;
2146 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2147 llvm::BasicBlock *OriginalBB = nullptr;
2148 llvm::BasicBlock *SkipAdjustBB = nullptr;
2149 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2151 // In the unspecified inheritance model, there might not be a vbtable at all,
2152 // in which case we need to skip the virtual base lookup. If there is a
2153 // vbtable, the first entry is a no-op entry that gives back the original
2154 // base, so look for a virtual base adjustment offset of zero.
2156 OriginalBB = Builder.GetInsertBlock();
2157 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2158 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2159 llvm::Value *IsVirtual =
2160 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2162 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2163 CGF.EmitBlock(VBaseAdjustBB);
2166 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2167 // know the vbptr offset.
2169 CharUnits offs = CharUnits::Zero();
2170 if (!RD->hasDefinition()) {
2171 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2172 unsigned DiagID = Diags.getCustomDiagID(
2173 DiagnosticsEngine::Error,
2174 "member pointer representation requires a "
2175 "complete class type for %0 to perform this expression");
2176 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2177 } else if (RD->getNumVBases())
2178 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2179 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2181 llvm::Value *VBPtr = nullptr;
2182 llvm::Value *VBaseOffs =
2183 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2184 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2186 // Merge control flow with the case where we didn't have to adjust.
2187 if (VBaseAdjustBB) {
2188 Builder.CreateBr(SkipAdjustBB);
2189 CGF.EmitBlock(SkipAdjustBB);
2190 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2191 Phi->addIncoming(Base, OriginalBB);
2192 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2195 return AdjustedBase;
2198 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2199 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2200 const MemberPointerType *MPT) {
2201 assert(MPT->isMemberDataPointer());
2202 unsigned AS = Base->getType()->getPointerAddressSpace();
2204 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2205 CGBuilderTy &Builder = CGF.Builder;
2206 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2207 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2209 // Extract the fields we need, regardless of model. We'll apply them if we
2211 llvm::Value *FieldOffset = MemPtr;
2212 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2213 llvm::Value *VBPtrOffset = nullptr;
2214 if (MemPtr->getType()->isStructTy()) {
2215 // We need to extract values.
2217 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2218 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2219 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2220 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2221 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2224 if (VirtualBaseAdjustmentOffset) {
2225 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2230 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2232 // Apply the offset, which we assume is non-null.
2234 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2236 // Cast the address to the appropriate pointer type, adopting the address
2237 // space of the base pointer.
2238 return Builder.CreateBitCast(Addr, PType);
2241 static MSInheritanceAttr::Spelling
2242 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2243 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2247 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2250 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2251 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2252 E->getCastKind() == CK_ReinterpretMemberPointer);
2254 // Use constant emission if we can.
2255 if (isa<llvm::Constant>(Src))
2256 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2258 // We may be adding or dropping fields from the member pointer, so we need
2259 // both types and the inheritance models of both records.
2260 const MemberPointerType *SrcTy =
2261 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2262 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2263 bool IsFunc = SrcTy->isMemberFunctionPointer();
2265 // If the classes use the same null representation, reinterpret_cast is a nop.
2266 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2267 if (IsReinterpret && IsFunc)
2270 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2271 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2272 if (IsReinterpret &&
2273 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2276 CGBuilderTy &Builder = CGF.Builder;
2278 // Branch past the conversion if Src is null.
2279 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2280 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2282 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2283 // pointer value of the destination type.
2284 if (IsReinterpret) {
2285 // For reinterpret casts, sema ensures that src and dst are both functions
2286 // or data and have the same size, which means the LLVM types should match.
2287 assert(Src->getType() == DstNull->getType());
2288 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2291 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2292 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2293 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2294 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2295 CGF.EmitBlock(ConvertBB);
2298 llvm::Value *FirstField = Src;
2299 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2300 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2301 llvm::Value *VBPtrOffset = nullptr;
2302 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2303 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2304 // We need to extract values.
2306 FirstField = Builder.CreateExtractValue(Src, I++);
2307 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2308 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2309 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2310 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2311 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2312 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2315 // For data pointers, we adjust the field offset directly. For functions, we
2316 // have a separate field.
2317 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2319 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2320 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2321 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2322 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2323 NVAdjustField = getZeroInt();
2324 if (isDerivedToBase)
2325 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2327 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2330 // FIXME PR15713: Support conversions through virtually derived classes.
2332 // Recompose dst from the null struct and the adjusted fields from src.
2333 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2335 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2338 Dst = llvm::UndefValue::get(DstNull->getType());
2340 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2341 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2342 Dst = Builder.CreateInsertValue(
2343 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2344 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2345 Dst = Builder.CreateInsertValue(
2346 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2347 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2348 Dst = Builder.CreateInsertValue(
2349 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2351 Builder.CreateBr(ContinueBB);
2353 // In the continuation, choose between DstNull and Dst.
2354 CGF.EmitBlock(ContinueBB);
2355 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2356 Phi->addIncoming(DstNull, OriginalBB);
2357 Phi->addIncoming(Dst, ConvertBB);
2362 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2363 llvm::Constant *Src) {
2364 const MemberPointerType *SrcTy =
2365 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2366 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2368 // If src is null, emit a new null for dst. We can't return src because dst
2369 // might have a new representation.
2370 if (MemberPointerConstantIsNull(SrcTy, Src))
2371 return EmitNullMemberPointer(DstTy);
2373 // We don't need to do anything for reinterpret_casts of non-null member
2374 // pointers. We should only get here when the two type representations have
2376 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2379 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2380 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2383 llvm::Constant *FirstField = Src;
2384 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2385 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2386 llvm::Constant *VBPtrOffset = nullptr;
2387 bool IsFunc = SrcTy->isMemberFunctionPointer();
2388 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2389 // We need to extract values.
2391 FirstField = Src->getAggregateElement(I++);
2392 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2393 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2394 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2395 VBPtrOffset = Src->getAggregateElement(I++);
2396 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2397 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2400 // For data pointers, we adjust the field offset directly. For functions, we
2401 // have a separate field.
2402 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2404 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2405 llvm::Constant *&NVAdjustField =
2406 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2407 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2408 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2409 NVAdjustField = getZeroInt();
2410 if (IsDerivedToBase)
2411 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2413 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2416 // FIXME PR15713: Support conversions through virtually derived classes.
2418 // Recompose dst from the null struct and the adjusted fields from src.
2419 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2422 llvm::SmallVector<llvm::Constant *, 4> Fields;
2423 Fields.push_back(FirstField);
2424 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2425 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2426 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2427 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2428 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2429 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2430 return llvm::ConstantStruct::getAnon(Fields);
2433 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2434 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2435 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2436 assert(MPT->isMemberFunctionPointer());
2437 const FunctionProtoType *FPT =
2438 MPT->getPointeeType()->castAs<FunctionProtoType>();
2439 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2440 llvm::FunctionType *FTy =
2441 CGM.getTypes().GetFunctionType(
2442 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2443 CGBuilderTy &Builder = CGF.Builder;
2445 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2447 // Extract the fields we need, regardless of model. We'll apply them if we
2449 llvm::Value *FunctionPointer = MemPtr;
2450 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2451 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2452 llvm::Value *VBPtrOffset = nullptr;
2453 if (MemPtr->getType()->isStructTy()) {
2454 // We need to extract values.
2456 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2457 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2458 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2459 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2460 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2461 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2462 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2465 if (VirtualBaseAdjustmentOffset) {
2466 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2470 if (NonVirtualBaseAdjustment) {
2471 // Apply the adjustment and cast back to the original struct type.
2472 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2473 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2474 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2477 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2480 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2481 return new MicrosoftCXXABI(CGM);
2484 // MS RTTI Overview:
2485 // The run time type information emitted by cl.exe contains 5 distinct types of
2486 // structures. Many of them reference each other.
2488 // TypeInfo: Static classes that are returned by typeid.
2490 // CompleteObjectLocator: Referenced by vftables. They contain information
2491 // required for dynamic casting, including OffsetFromTop. They also contain
2492 // a reference to the TypeInfo for the type and a reference to the
2493 // CompleteHierarchyDescriptor for the type.
2495 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2496 // Used during dynamic_cast to walk a class hierarchy. References a base
2497 // class array and the size of said array.
2499 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2500 // somewhat of a misnomer because the most derived class is also in the list
2501 // as well as multiple copies of virtual bases (if they occur multiple times
2502 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2503 // every path in the hierarchy, in pre-order depth first order. Note, we do
2504 // not declare a specific llvm type for BaseClassArray, it's merely an array
2505 // of BaseClassDescriptor pointers.
2507 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2508 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2509 // BaseClassArray is. It contains information about a class within a
2510 // hierarchy such as: is this base is ambiguous and what is its offset in the
2511 // vbtable. The names of the BaseClassDescriptors have all of their fields
2512 // mangled into them so they can be aggressively deduplicated by the linker.
2514 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2515 StringRef MangledName("\01??_7type_info@@6B@");
2516 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2518 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2520 llvm::GlobalVariable::ExternalLinkage,
2521 /*Initializer=*/nullptr, MangledName);
2526 /// \brief A Helper struct that stores information about a class in a class
2527 /// hierarchy. The information stored in these structs struct is used during
2528 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2529 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2530 // implicit depth first pre-order tree connectivity. getFirstChild and
2531 // getNextSibling allow us to walk the tree efficiently.
2532 struct MSRTTIClass {
2534 IsPrivateOnPath = 1 | 8,
2538 HasHierarchyDescriptor = 64
2540 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
2541 uint32_t initialize(const MSRTTIClass *Parent,
2542 const CXXBaseSpecifier *Specifier);
2544 MSRTTIClass *getFirstChild() { return this + 1; }
2545 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
2546 return Child + 1 + Child->NumBases;
2549 const CXXRecordDecl *RD, *VirtualRoot;
2550 uint32_t Flags, NumBases, OffsetInVBase;
2553 /// \brief Recursively initialize the base class array.
2554 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
2555 const CXXBaseSpecifier *Specifier) {
2556 Flags = HasHierarchyDescriptor;
2558 VirtualRoot = nullptr;
2561 if (Specifier->getAccessSpecifier() != AS_public)
2562 Flags |= IsPrivate | IsPrivateOnPath;
2563 if (Specifier->isVirtual()) {
2568 if (Parent->Flags & IsPrivateOnPath)
2569 Flags |= IsPrivateOnPath;
2570 VirtualRoot = Parent->VirtualRoot;
2571 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
2572 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
2576 MSRTTIClass *Child = getFirstChild();
2577 for (const CXXBaseSpecifier &Base : RD->bases()) {
2578 NumBases += Child->initialize(this, &Base) + 1;
2579 Child = getNextChild(Child);
2584 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
2585 switch (Ty->getLinkage()) {
2587 case InternalLinkage:
2588 case UniqueExternalLinkage:
2589 return llvm::GlobalValue::InternalLinkage;
2591 case VisibleNoLinkage:
2592 case ExternalLinkage:
2593 return llvm::GlobalValue::LinkOnceODRLinkage;
2595 llvm_unreachable("Invalid linkage!");
2598 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
2599 /// calls to the module and information about the most derived class in a
2601 struct MSRTTIBuilder {
2603 HasBranchingHierarchy = 1,
2604 HasVirtualBranchingHierarchy = 2,
2605 HasAmbiguousBases = 4
2608 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
2609 : CGM(ABI.CGM), Context(CGM.getContext()),
2610 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
2611 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
2614 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
2615 llvm::GlobalVariable *
2616 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
2617 llvm::GlobalVariable *getClassHierarchyDescriptor();
2618 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
2621 ASTContext &Context;
2622 llvm::LLVMContext &VMContext;
2623 llvm::Module &Module;
2624 const CXXRecordDecl *RD;
2625 llvm::GlobalVariable::LinkageTypes Linkage;
2626 MicrosoftCXXABI &ABI;
2631 /// \brief Recursively serializes a class hierarchy in pre-order depth first
2633 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
2634 const CXXRecordDecl *RD) {
2635 Classes.push_back(MSRTTIClass(RD));
2636 for (const CXXBaseSpecifier &Base : RD->bases())
2637 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
2640 /// \brief Find ambiguity among base classes.
2642 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
2643 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
2644 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
2645 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
2646 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
2647 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
2648 !VirtualBases.insert(Class->RD)) {
2649 Class = MSRTTIClass::getNextChild(Class);
2652 if (!UniqueBases.insert(Class->RD))
2653 AmbiguousBases.insert(Class->RD);
2656 if (AmbiguousBases.empty())
2658 for (MSRTTIClass &Class : Classes)
2659 if (AmbiguousBases.count(Class.RD))
2660 Class.Flags |= MSRTTIClass::IsAmbiguous;
2663 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
2664 SmallString<256> MangledName;
2666 llvm::raw_svector_ostream Out(MangledName);
2667 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
2670 // Check to see if we've already declared this ClassHierarchyDescriptor.
2671 if (auto CHD = Module.getNamedGlobal(MangledName))
2674 // Serialize the class hierarchy and initialize the CHD Fields.
2675 SmallVector<MSRTTIClass, 8> Classes;
2676 serializeClassHierarchy(Classes, RD);
2677 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
2678 detectAmbiguousBases(Classes);
2680 for (auto Class : Classes) {
2681 if (Class.RD->getNumBases() > 1)
2682 Flags |= HasBranchingHierarchy;
2683 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
2684 // believe the field isn't actually used.
2685 if (Class.Flags & MSRTTIClass::IsAmbiguous)
2686 Flags |= HasAmbiguousBases;
2688 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
2689 Flags |= HasVirtualBranchingHierarchy;
2690 // These gep indices are used to get the address of the first element of the
2691 // base class array.
2692 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
2693 llvm::ConstantInt::get(CGM.IntTy, 0)};
2695 // Forward-declare the class hierarchy descriptor
2696 auto Type = ABI.getClassHierarchyDescriptorType();
2697 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
2698 /*Initializer=*/nullptr,
2699 MangledName.c_str());
2701 // Initialize the base class ClassHierarchyDescriptor.
2702 llvm::Constant *Fields[] = {
2703 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
2704 llvm::ConstantInt::get(CGM.IntTy, Flags),
2705 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
2706 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
2707 getBaseClassArray(Classes),
2708 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
2710 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
2714 llvm::GlobalVariable *
2715 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
2716 SmallString<256> MangledName;
2718 llvm::raw_svector_ostream Out(MangledName);
2719 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
2722 // Forward-declare the base class array.
2723 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
2724 // mode) bytes of padding. We provide a pointer sized amount of padding by
2725 // adding +1 to Classes.size(). The sections have pointer alignment and are
2726 // marked pick-any so it shouldn't matter.
2727 llvm::Type *PtrType = ABI.getImageRelativeType(
2728 ABI.getBaseClassDescriptorType()->getPointerTo());
2729 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
2730 auto *BCA = new llvm::GlobalVariable(
2732 /*Constant=*/true, Linkage, /*Initializer=*/nullptr, MangledName.c_str());
2734 // Initialize the BaseClassArray.
2735 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
2736 for (MSRTTIClass &Class : Classes)
2737 BaseClassArrayData.push_back(
2738 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
2739 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
2740 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
2744 llvm::GlobalVariable *
2745 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
2746 // Compute the fields for the BaseClassDescriptor. They are computed up front
2747 // because they are mangled into the name of the object.
2748 uint32_t OffsetInVBTable = 0;
2749 int32_t VBPtrOffset = -1;
2750 if (Class.VirtualRoot) {
2751 auto &VTableContext = CGM.getMicrosoftVTableContext();
2752 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
2753 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
2756 SmallString<256> MangledName;
2758 llvm::raw_svector_ostream Out(MangledName);
2759 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
2760 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
2764 // Check to see if we've already declared this object.
2765 if (auto BCD = Module.getNamedGlobal(MangledName))
2768 // Forward-declare the base class descriptor.
2769 auto Type = ABI.getBaseClassDescriptorType();
2770 auto BCD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
2771 /*Initializer=*/nullptr,
2772 MangledName.c_str());
2774 // Initialize the BaseClassDescriptor.
2775 llvm::Constant *Fields[] = {
2776 ABI.getImageRelativeConstant(
2777 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
2778 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
2779 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
2780 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
2781 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
2782 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
2783 ABI.getImageRelativeConstant(
2784 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
2786 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
2790 llvm::GlobalVariable *
2791 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
2792 SmallString<256> MangledName;
2794 llvm::raw_svector_ostream Out(MangledName);
2795 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
2798 // Check to see if we've already computed this complete object locator.
2799 if (auto COL = Module.getNamedGlobal(MangledName))
2802 // Compute the fields of the complete object locator.
2803 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
2804 int VFPtrOffset = 0;
2805 // The offset includes the vtordisp if one exists.
2806 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
2807 if (Context.getASTRecordLayout(RD)
2808 .getVBaseOffsetsMap()
2810 ->second.hasVtorDisp())
2811 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
2813 // Forward-declare the complete object locator.
2814 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
2815 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
2816 /*Initializer=*/nullptr, MangledName.c_str());
2818 // Initialize the CompleteObjectLocator.
2819 llvm::Constant *Fields[] = {
2820 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
2821 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
2822 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
2823 ABI.getImageRelativeConstant(
2824 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
2825 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
2826 ABI.getImageRelativeConstant(COL),
2828 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
2829 if (!ABI.isImageRelative())
2830 FieldsRef = FieldsRef.drop_back();
2831 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
2835 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
2836 /// llvm::GlobalVariable * because different type descriptors have different
2837 /// types, and need to be abstracted. They are abstracting by casting the
2838 /// address to an Int8PtrTy.
2839 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
2840 SmallString<256> MangledName, TypeInfoString;
2842 llvm::raw_svector_ostream Out(MangledName);
2843 getMangleContext().mangleCXXRTTI(Type, Out);
2846 // Check to see if we've already declared this TypeDescriptor.
2847 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
2848 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
2850 // Compute the fields for the TypeDescriptor.
2852 llvm::raw_svector_ostream Out(TypeInfoString);
2853 getMangleContext().mangleCXXRTTIName(Type, Out);
2856 // Declare and initialize the TypeDescriptor.
2857 llvm::Constant *Fields[] = {
2858 getTypeInfoVTable(CGM), // VFPtr
2859 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
2860 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
2861 llvm::StructType *TypeDescriptorType =
2862 getTypeDescriptorType(TypeInfoString);
2863 return llvm::ConstantExpr::getBitCast(
2864 new llvm::GlobalVariable(
2865 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
2866 getLinkageForRTTI(Type),
2867 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
2868 MangledName.c_str()),
2872 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
2873 llvm::GlobalVariable *
2874 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
2875 const VPtrInfo *Info) {
2876 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);