1 //===--- CGCXXRTTI.cpp - Emit LLVM Code for C++ RTTI descriptors ----------===//
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 contains code dealing with C++ code generation of RTTI descriptors.
12 //===----------------------------------------------------------------------===//
14 #include "CodeGenModule.h"
16 #include "clang/AST/RecordLayout.h"
17 #include "clang/AST/Type.h"
18 #include "clang/Frontend/CodeGenOptions.h"
19 #include "CGObjCRuntime.h"
21 using namespace clang;
22 using namespace CodeGen;
26 CodeGenModule &CGM; // Per-module state.
27 llvm::LLVMContext &VMContext;
29 const llvm::Type *Int8PtrTy;
31 /// Fields - The fields of the RTTI descriptor currently being built.
32 llvm::SmallVector<llvm::Constant *, 16> Fields;
34 /// GetAddrOfTypeName - Returns the mangled type name of the given type.
35 llvm::GlobalVariable *
36 GetAddrOfTypeName(QualType Ty, llvm::GlobalVariable::LinkageTypes Linkage);
38 /// GetAddrOfExternalRTTIDescriptor - Returns the constant for the RTTI
39 /// descriptor of the given type.
40 llvm::Constant *GetAddrOfExternalRTTIDescriptor(QualType Ty);
42 /// BuildVTablePointer - Build the vtable pointer for the given type.
43 void BuildVTablePointer(const Type *Ty);
45 /// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
46 /// inheritance, according to the Itanium C++ ABI, 2.9.5p6b.
47 void BuildSIClassTypeInfo(const CXXRecordDecl *RD);
49 /// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
50 /// classes with bases that do not satisfy the abi::__si_class_type_info
51 /// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
52 void BuildVMIClassTypeInfo(const CXXRecordDecl *RD);
54 /// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, used
55 /// for pointer types.
56 void BuildPointerTypeInfo(QualType PointeeTy);
58 /// BuildObjCObjectTypeInfo - Build the appropriate kind of
59 /// type_info for an object type.
60 void BuildObjCObjectTypeInfo(const ObjCObjectType *Ty);
62 /// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info
63 /// struct, used for member pointer types.
64 void BuildPointerToMemberTypeInfo(const MemberPointerType *Ty);
67 RTTIBuilder(CodeGenModule &CGM) : CGM(CGM),
68 VMContext(CGM.getModule().getContext()),
69 Int8PtrTy(llvm::Type::getInt8PtrTy(VMContext)) { }
71 // Pointer type info flags.
73 /// PTI_Const - Type has const qualifier.
76 /// PTI_Volatile - Type has volatile qualifier.
79 /// PTI_Restrict - Type has restrict qualifier.
82 /// PTI_Incomplete - Type is incomplete.
85 /// PTI_ContainingClassIncomplete - Containing class is incomplete.
86 /// (in pointer to member).
87 PTI_ContainingClassIncomplete = 0x10
90 // VMI type info flags.
92 /// VMI_NonDiamondRepeat - Class has non-diamond repeated inheritance.
93 VMI_NonDiamondRepeat = 0x1,
95 /// VMI_DiamondShaped - Class is diamond shaped.
96 VMI_DiamondShaped = 0x2
99 // Base class type info flags.
101 /// BCTI_Virtual - Base class is virtual.
104 /// BCTI_Public - Base class is public.
108 /// BuildTypeInfo - Build the RTTI type info struct for the given type.
110 /// \param Force - true to force the creation of this RTTI value
111 /// \param ForEH - true if this is for exception handling
112 llvm::Constant *BuildTypeInfo(QualType Ty, bool Force = false);
116 llvm::GlobalVariable *
117 RTTIBuilder::GetAddrOfTypeName(QualType Ty,
118 llvm::GlobalVariable::LinkageTypes Linkage) {
119 llvm::SmallString<256> OutName;
120 llvm::raw_svector_ostream Out(OutName);
121 CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(Ty, Out);
123 llvm::StringRef Name = OutName.str();
125 // We know that the mangled name of the type starts at index 4 of the
126 // mangled name of the typename, so we can just index into it in order to
127 // get the mangled name of the type.
128 llvm::Constant *Init = llvm::ConstantArray::get(VMContext, Name.substr(4));
130 llvm::GlobalVariable *GV =
131 CGM.CreateOrReplaceCXXRuntimeVariable(Name, Init->getType(), Linkage);
133 GV->setInitializer(Init);
138 llvm::Constant *RTTIBuilder::GetAddrOfExternalRTTIDescriptor(QualType Ty) {
139 // Mangle the RTTI name.
140 llvm::SmallString<256> OutName;
141 llvm::raw_svector_ostream Out(OutName);
142 CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out);
144 llvm::StringRef Name = OutName.str();
146 // Look for an existing global.
147 llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name);
150 // Create a new global variable.
151 GV = new llvm::GlobalVariable(CGM.getModule(), Int8PtrTy, /*Constant=*/true,
152 llvm::GlobalValue::ExternalLinkage, 0, Name);
155 return llvm::ConstantExpr::getBitCast(GV, Int8PtrTy);
158 /// TypeInfoIsInStandardLibrary - Given a builtin type, returns whether the type
159 /// info for that type is defined in the standard library.
160 static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) {
161 // Itanium C++ ABI 2.9.2:
162 // Basic type information (e.g. for "int", "bool", etc.) will be kept in
163 // the run-time support library. Specifically, the run-time support
164 // library should contain type_info objects for the types X, X* and
165 // X const*, for every X in: void, std::nullptr_t, bool, wchar_t, char,
166 // unsigned char, signed char, short, unsigned short, int, unsigned int,
167 // long, unsigned long, long long, unsigned long long, float, double,
168 // long double, char16_t, char32_t, and the IEEE 754r decimal and
169 // half-precision floating point types.
170 switch (Ty->getKind()) {
171 case BuiltinType::Void:
172 case BuiltinType::NullPtr:
173 case BuiltinType::Bool:
174 case BuiltinType::WChar_S:
175 case BuiltinType::WChar_U:
176 case BuiltinType::Char_U:
177 case BuiltinType::Char_S:
178 case BuiltinType::UChar:
179 case BuiltinType::SChar:
180 case BuiltinType::Short:
181 case BuiltinType::UShort:
182 case BuiltinType::Int:
183 case BuiltinType::UInt:
184 case BuiltinType::Long:
185 case BuiltinType::ULong:
186 case BuiltinType::LongLong:
187 case BuiltinType::ULongLong:
188 case BuiltinType::Float:
189 case BuiltinType::Double:
190 case BuiltinType::LongDouble:
191 case BuiltinType::Char16:
192 case BuiltinType::Char32:
193 case BuiltinType::Int128:
194 case BuiltinType::UInt128:
197 case BuiltinType::Overload:
198 case BuiltinType::Dependent:
199 case BuiltinType::BoundMember:
200 case BuiltinType::UnknownAny:
201 llvm_unreachable("asking for RRTI for a placeholder type!");
203 case BuiltinType::ObjCId:
204 case BuiltinType::ObjCClass:
205 case BuiltinType::ObjCSel:
206 assert(false && "FIXME: Objective-C types are unsupported!");
213 static bool TypeInfoIsInStandardLibrary(const PointerType *PointerTy) {
214 QualType PointeeTy = PointerTy->getPointeeType();
215 const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(PointeeTy);
219 // Check the qualifiers.
220 Qualifiers Quals = PointeeTy.getQualifiers();
226 return TypeInfoIsInStandardLibrary(BuiltinTy);
229 /// IsStandardLibraryRTTIDescriptor - Returns whether the type
230 /// information for the given type exists in the standard library.
231 static bool IsStandardLibraryRTTIDescriptor(QualType Ty) {
232 // Type info for builtin types is defined in the standard library.
233 if (const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(Ty))
234 return TypeInfoIsInStandardLibrary(BuiltinTy);
236 // Type info for some pointer types to builtin types is defined in the
238 if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
239 return TypeInfoIsInStandardLibrary(PointerTy);
244 /// ShouldUseExternalRTTIDescriptor - Returns whether the type information for
245 /// the given type exists somewhere else, and that we should not emit the type
246 /// information in this translation unit. Assumes that it is not a
247 /// standard-library type.
248 static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM, QualType Ty) {
249 ASTContext &Context = CGM.getContext();
251 // If RTTI is disabled, don't consider key functions.
252 if (!Context.getLangOptions().RTTI) return false;
254 if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
255 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl());
256 if (!RD->hasDefinition())
259 if (!RD->isDynamicClass())
262 return !CGM.getVTables().ShouldEmitVTableInThisTU(RD);
268 /// IsIncompleteClassType - Returns whether the given record type is incomplete.
269 static bool IsIncompleteClassType(const RecordType *RecordTy) {
270 return !RecordTy->getDecl()->isDefinition();
273 /// ContainsIncompleteClassType - Returns whether the given type contains an
274 /// incomplete class type. This is true if
276 /// * The given type is an incomplete class type.
277 /// * The given type is a pointer type whose pointee type contains an
278 /// incomplete class type.
279 /// * The given type is a member pointer type whose class is an incomplete
281 /// * The given type is a member pointer type whoise pointee type contains an
282 /// incomplete class type.
283 /// is an indirect or direct pointer to an incomplete class type.
284 static bool ContainsIncompleteClassType(QualType Ty) {
285 if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
286 if (IsIncompleteClassType(RecordTy))
290 if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
291 return ContainsIncompleteClassType(PointerTy->getPointeeType());
293 if (const MemberPointerType *MemberPointerTy =
294 dyn_cast<MemberPointerType>(Ty)) {
295 // Check if the class type is incomplete.
296 const RecordType *ClassType = cast<RecordType>(MemberPointerTy->getClass());
297 if (IsIncompleteClassType(ClassType))
300 return ContainsIncompleteClassType(MemberPointerTy->getPointeeType());
306 /// getTypeInfoLinkage - Return the linkage that the type info and type info
307 /// name constants should have for the given type.
308 static llvm::GlobalVariable::LinkageTypes
309 getTypeInfoLinkage(CodeGenModule &CGM, QualType Ty) {
310 // Itanium C++ ABI 2.9.5p7:
311 // In addition, it and all of the intermediate abi::__pointer_type_info
312 // structs in the chain down to the abi::__class_type_info for the
313 // incomplete class type must be prevented from resolving to the
314 // corresponding type_info structs for the complete class type, possibly
315 // by making them local static objects. Finally, a dummy class RTTI is
316 // generated for the incomplete type that will not resolve to the final
317 // complete class RTTI (because the latter need not exist), possibly by
318 // making it a local static object.
319 if (ContainsIncompleteClassType(Ty))
320 return llvm::GlobalValue::InternalLinkage;
322 switch (Ty->getLinkage()) {
324 case InternalLinkage:
325 case UniqueExternalLinkage:
326 return llvm::GlobalValue::InternalLinkage;
328 case ExternalLinkage:
329 if (!CGM.getLangOptions().RTTI) {
330 // RTTI is not enabled, which means that this type info struct is going
331 // to be used for exception handling. Give it linkonce_odr linkage.
332 return llvm::GlobalValue::LinkOnceODRLinkage;
335 if (const RecordType *Record = dyn_cast<RecordType>(Ty)) {
336 const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
337 if (RD->isDynamicClass())
338 return CGM.getVTableLinkage(RD);
341 return llvm::GlobalValue::LinkOnceODRLinkage;
344 return llvm::GlobalValue::LinkOnceODRLinkage;
347 // CanUseSingleInheritance - Return whether the given record decl has a "single,
348 // public, non-virtual base at offset zero (i.e. the derived class is dynamic
349 // iff the base is)", according to Itanium C++ ABI, 2.95p6b.
350 static bool CanUseSingleInheritance(const CXXRecordDecl *RD) {
351 // Check the number of bases.
352 if (RD->getNumBases() != 1)
356 CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin();
358 // Check that the base is not virtual.
359 if (Base->isVirtual())
362 // Check that the base is public.
363 if (Base->getAccessSpecifier() != AS_public)
366 // Check that the class is dynamic iff the base is.
367 const CXXRecordDecl *BaseDecl =
368 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
369 if (!BaseDecl->isEmpty() &&
370 BaseDecl->isDynamicClass() != RD->isDynamicClass())
376 void RTTIBuilder::BuildVTablePointer(const Type *Ty) {
377 // abi::__class_type_info.
378 static const char * const ClassTypeInfo =
379 "_ZTVN10__cxxabiv117__class_type_infoE";
380 // abi::__si_class_type_info.
381 static const char * const SIClassTypeInfo =
382 "_ZTVN10__cxxabiv120__si_class_type_infoE";
383 // abi::__vmi_class_type_info.
384 static const char * const VMIClassTypeInfo =
385 "_ZTVN10__cxxabiv121__vmi_class_type_infoE";
387 const char *VTableName = 0;
389 switch (Ty->getTypeClass()) {
390 #define TYPE(Class, Base)
391 #define ABSTRACT_TYPE(Class, Base)
392 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
393 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
394 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
395 #include "clang/AST/TypeNodes.def"
396 assert(false && "Non-canonical and dependent types shouldn't get here");
398 case Type::LValueReference:
399 case Type::RValueReference:
400 assert(false && "References shouldn't get here");
403 // GCC treats vector and complex types as fundamental types.
405 case Type::ExtVector:
407 // FIXME: GCC treats block pointers as fundamental types?!
408 case Type::BlockPointer:
409 // abi::__fundamental_type_info.
410 VTableName = "_ZTVN10__cxxabiv123__fundamental_type_infoE";
413 case Type::ConstantArray:
414 case Type::IncompleteArray:
415 case Type::VariableArray:
416 // abi::__array_type_info.
417 VTableName = "_ZTVN10__cxxabiv117__array_type_infoE";
420 case Type::FunctionNoProto:
421 case Type::FunctionProto:
422 // abi::__function_type_info.
423 VTableName = "_ZTVN10__cxxabiv120__function_type_infoE";
427 // abi::__enum_type_info.
428 VTableName = "_ZTVN10__cxxabiv116__enum_type_infoE";
432 const CXXRecordDecl *RD =
433 cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
435 if (!RD->hasDefinition() || !RD->getNumBases()) {
436 VTableName = ClassTypeInfo;
437 } else if (CanUseSingleInheritance(RD)) {
438 VTableName = SIClassTypeInfo;
440 VTableName = VMIClassTypeInfo;
446 case Type::ObjCObject:
447 // Ignore protocol qualifiers.
448 Ty = cast<ObjCObjectType>(Ty)->getBaseType().getTypePtr();
450 // Handle id and Class.
451 if (isa<BuiltinType>(Ty)) {
452 VTableName = ClassTypeInfo;
456 assert(isa<ObjCInterfaceType>(Ty));
459 case Type::ObjCInterface:
460 if (cast<ObjCInterfaceType>(Ty)->getDecl()->getSuperClass()) {
461 VTableName = SIClassTypeInfo;
463 VTableName = ClassTypeInfo;
467 case Type::ObjCObjectPointer:
469 // abi::__pointer_type_info.
470 VTableName = "_ZTVN10__cxxabiv119__pointer_type_infoE";
473 case Type::MemberPointer:
474 // abi::__pointer_to_member_type_info.
475 VTableName = "_ZTVN10__cxxabiv129__pointer_to_member_type_infoE";
479 llvm::Constant *VTable =
480 CGM.getModule().getOrInsertGlobal(VTableName, Int8PtrTy);
482 const llvm::Type *PtrDiffTy =
483 CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
485 // The vtable address point is 2.
486 llvm::Constant *Two = llvm::ConstantInt::get(PtrDiffTy, 2);
487 VTable = llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, &Two, 1);
488 VTable = llvm::ConstantExpr::getBitCast(VTable, Int8PtrTy);
490 Fields.push_back(VTable);
493 // maybeUpdateRTTILinkage - Will update the linkage of the RTTI data structures
494 // from available_externally to the correct linkage if necessary. An example of
501 // const std::type_info &g() {
507 // When we're generating the typeid(A) expression, we do not yet know that
508 // A's key function is defined in this translation unit, so we will give the
509 // typeinfo and typename structures available_externally linkage. When A::f
510 // forces the vtable to be generated, we need to change the linkage of the
511 // typeinfo and typename structs, otherwise we'll end up with undefined
512 // externals when linking.
514 maybeUpdateRTTILinkage(CodeGenModule &CGM, llvm::GlobalVariable *GV,
516 // We're only interested in globals with available_externally linkage.
517 if (!GV->hasAvailableExternallyLinkage())
520 // Get the real linkage for the type.
521 llvm::GlobalVariable::LinkageTypes Linkage = getTypeInfoLinkage(CGM, Ty);
523 // If variable is supposed to have available_externally linkage, we don't
524 // need to do anything.
525 if (Linkage == llvm::GlobalVariable::AvailableExternallyLinkage)
528 // Update the typeinfo linkage.
529 GV->setLinkage(Linkage);
531 // Get the typename global.
532 llvm::SmallString<256> OutName;
533 llvm::raw_svector_ostream Out(OutName);
534 CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(Ty, Out);
536 llvm::StringRef Name = OutName.str();
538 llvm::GlobalVariable *TypeNameGV = CGM.getModule().getNamedGlobal(Name);
540 assert(TypeNameGV->hasAvailableExternallyLinkage() &&
541 "Type name has different linkage from type info!");
543 // And update its linkage.
544 TypeNameGV->setLinkage(Linkage);
547 llvm::Constant *RTTIBuilder::BuildTypeInfo(QualType Ty, bool Force) {
548 // We want to operate on the canonical type.
549 Ty = CGM.getContext().getCanonicalType(Ty);
551 // Check if we've already emitted an RTTI descriptor for this type.
552 llvm::SmallString<256> OutName;
553 llvm::raw_svector_ostream Out(OutName);
554 CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out);
556 llvm::StringRef Name = OutName.str();
558 llvm::GlobalVariable *OldGV = CGM.getModule().getNamedGlobal(Name);
559 if (OldGV && !OldGV->isDeclaration()) {
560 maybeUpdateRTTILinkage(CGM, OldGV, Ty);
562 return llvm::ConstantExpr::getBitCast(OldGV, Int8PtrTy);
565 // Check if there is already an external RTTI descriptor for this type.
566 bool IsStdLib = IsStandardLibraryRTTIDescriptor(Ty);
567 if (!Force && (IsStdLib || ShouldUseExternalRTTIDescriptor(CGM, Ty)))
568 return GetAddrOfExternalRTTIDescriptor(Ty);
570 // Emit the standard library with external linkage.
571 llvm::GlobalVariable::LinkageTypes Linkage;
573 Linkage = llvm::GlobalValue::ExternalLinkage;
575 Linkage = getTypeInfoLinkage(CGM, Ty);
577 // Add the vtable pointer.
578 BuildVTablePointer(cast<Type>(Ty));
581 llvm::GlobalVariable *TypeName = GetAddrOfTypeName(Ty, Linkage);
583 const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
584 Fields.push_back(llvm::ConstantExpr::getBitCast(TypeName, Int8PtrTy));
586 switch (Ty->getTypeClass()) {
587 #define TYPE(Class, Base)
588 #define ABSTRACT_TYPE(Class, Base)
589 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
590 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
591 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
592 #include "clang/AST/TypeNodes.def"
593 assert(false && "Non-canonical and dependent types shouldn't get here");
595 // GCC treats vector types as fundamental types.
598 case Type::ExtVector:
600 case Type::BlockPointer:
601 // Itanium C++ ABI 2.9.5p4:
602 // abi::__fundamental_type_info adds no data members to std::type_info.
605 case Type::LValueReference:
606 case Type::RValueReference:
607 assert(false && "References shouldn't get here");
609 case Type::ConstantArray:
610 case Type::IncompleteArray:
611 case Type::VariableArray:
612 // Itanium C++ ABI 2.9.5p5:
613 // abi::__array_type_info adds no data members to std::type_info.
616 case Type::FunctionNoProto:
617 case Type::FunctionProto:
618 // Itanium C++ ABI 2.9.5p5:
619 // abi::__function_type_info adds no data members to std::type_info.
623 // Itanium C++ ABI 2.9.5p5:
624 // abi::__enum_type_info adds no data members to std::type_info.
628 const CXXRecordDecl *RD =
629 cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
630 if (!RD->hasDefinition() || !RD->getNumBases()) {
631 // We don't need to emit any fields.
635 if (CanUseSingleInheritance(RD))
636 BuildSIClassTypeInfo(RD);
638 BuildVMIClassTypeInfo(RD);
643 case Type::ObjCObject:
644 case Type::ObjCInterface:
645 BuildObjCObjectTypeInfo(cast<ObjCObjectType>(Ty));
648 case Type::ObjCObjectPointer:
649 BuildPointerTypeInfo(cast<ObjCObjectPointerType>(Ty)->getPointeeType());
653 BuildPointerTypeInfo(cast<PointerType>(Ty)->getPointeeType());
656 case Type::MemberPointer:
657 BuildPointerToMemberTypeInfo(cast<MemberPointerType>(Ty));
661 llvm::Constant *Init = llvm::ConstantStruct::getAnon(Fields);
663 llvm::GlobalVariable *GV =
664 new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
665 /*Constant=*/true, Linkage, Init, Name);
667 // If there's already an old global variable, replace it with the new one.
670 llvm::Constant *NewPtr =
671 llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
672 OldGV->replaceAllUsesWith(NewPtr);
673 OldGV->eraseFromParent();
676 // GCC only relies on the uniqueness of the type names, not the
677 // type_infos themselves, so we can emit these as hidden symbols.
678 // But don't do this if we're worried about strict visibility
680 if (const RecordType *RT = dyn_cast<RecordType>(Ty)) {
681 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
683 CGM.setTypeVisibility(GV, RD, CodeGenModule::TVK_ForRTTI);
684 CGM.setTypeVisibility(TypeName, RD, CodeGenModule::TVK_ForRTTIName);
686 Visibility TypeInfoVisibility = DefaultVisibility;
687 if (CGM.getCodeGenOpts().HiddenWeakVTables &&
688 Linkage == llvm::GlobalValue::LinkOnceODRLinkage)
689 TypeInfoVisibility = HiddenVisibility;
691 // The type name should have the same visibility as the type itself.
692 Visibility ExplicitVisibility = Ty->getVisibility();
693 TypeName->setVisibility(CodeGenModule::
694 GetLLVMVisibility(ExplicitVisibility));
696 TypeInfoVisibility = minVisibility(TypeInfoVisibility, Ty->getVisibility());
697 GV->setVisibility(CodeGenModule::GetLLVMVisibility(TypeInfoVisibility));
700 GV->setUnnamedAddr(true);
702 return llvm::ConstantExpr::getBitCast(GV, Int8PtrTy);
705 /// ComputeQualifierFlags - Compute the pointer type info flags from the
707 static unsigned ComputeQualifierFlags(Qualifiers Quals) {
710 if (Quals.hasConst())
711 Flags |= RTTIBuilder::PTI_Const;
712 if (Quals.hasVolatile())
713 Flags |= RTTIBuilder::PTI_Volatile;
714 if (Quals.hasRestrict())
715 Flags |= RTTIBuilder::PTI_Restrict;
720 /// BuildObjCObjectTypeInfo - Build the appropriate kind of type_info
721 /// for the given Objective-C object type.
722 void RTTIBuilder::BuildObjCObjectTypeInfo(const ObjCObjectType *OT) {
724 const Type *T = OT->getBaseType().getTypePtr();
725 assert(isa<BuiltinType>(T) || isa<ObjCInterfaceType>(T));
727 // The builtin types are abi::__class_type_infos and don't require
729 if (isa<BuiltinType>(T)) return;
731 ObjCInterfaceDecl *Class = cast<ObjCInterfaceType>(T)->getDecl();
732 ObjCInterfaceDecl *Super = Class->getSuperClass();
734 // Root classes are also __class_type_info.
737 QualType SuperTy = CGM.getContext().getObjCInterfaceType(Super);
739 // Everything else is single inheritance.
740 llvm::Constant *BaseTypeInfo = RTTIBuilder(CGM).BuildTypeInfo(SuperTy);
741 Fields.push_back(BaseTypeInfo);
744 /// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
745 /// inheritance, according to the Itanium C++ ABI, 2.95p6b.
746 void RTTIBuilder::BuildSIClassTypeInfo(const CXXRecordDecl *RD) {
747 // Itanium C++ ABI 2.9.5p6b:
748 // It adds to abi::__class_type_info a single member pointing to the
749 // type_info structure for the base type,
750 llvm::Constant *BaseTypeInfo =
751 RTTIBuilder(CGM).BuildTypeInfo(RD->bases_begin()->getType());
752 Fields.push_back(BaseTypeInfo);
756 /// SeenBases - Contains virtual and non-virtual bases seen when traversing
757 /// a class hierarchy.
759 llvm::SmallPtrSet<const CXXRecordDecl *, 16> NonVirtualBases;
760 llvm::SmallPtrSet<const CXXRecordDecl *, 16> VirtualBases;
764 /// ComputeVMIClassTypeInfoFlags - Compute the value of the flags member in
765 /// abi::__vmi_class_type_info.
767 static unsigned ComputeVMIClassTypeInfoFlags(const CXXBaseSpecifier *Base,
772 const CXXRecordDecl *BaseDecl =
773 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
775 if (Base->isVirtual()) {
776 if (Bases.VirtualBases.count(BaseDecl)) {
777 // If this virtual base has been seen before, then the class is diamond
779 Flags |= RTTIBuilder::VMI_DiamondShaped;
781 if (Bases.NonVirtualBases.count(BaseDecl))
782 Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
784 // Mark the virtual base as seen.
785 Bases.VirtualBases.insert(BaseDecl);
788 if (Bases.NonVirtualBases.count(BaseDecl)) {
789 // If this non-virtual base has been seen before, then the class has non-
790 // diamond shaped repeated inheritance.
791 Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
793 if (Bases.VirtualBases.count(BaseDecl))
794 Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
796 // Mark the non-virtual base as seen.
797 Bases.NonVirtualBases.insert(BaseDecl);
802 for (CXXRecordDecl::base_class_const_iterator I = BaseDecl->bases_begin(),
803 E = BaseDecl->bases_end(); I != E; ++I)
804 Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
809 static unsigned ComputeVMIClassTypeInfoFlags(const CXXRecordDecl *RD) {
814 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
815 E = RD->bases_end(); I != E; ++I)
816 Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
821 /// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
822 /// classes with bases that do not satisfy the abi::__si_class_type_info
823 /// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
824 void RTTIBuilder::BuildVMIClassTypeInfo(const CXXRecordDecl *RD) {
825 const llvm::Type *UnsignedIntLTy =
826 CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
828 // Itanium C++ ABI 2.9.5p6c:
829 // __flags is a word with flags describing details about the class
830 // structure, which may be referenced by using the __flags_masks
831 // enumeration. These flags refer to both direct and indirect bases.
832 unsigned Flags = ComputeVMIClassTypeInfoFlags(RD);
833 Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
835 // Itanium C++ ABI 2.9.5p6c:
836 // __base_count is a word with the number of direct proper base class
837 // descriptions that follow.
838 Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, RD->getNumBases()));
840 if (!RD->getNumBases())
843 const llvm::Type *LongLTy =
844 CGM.getTypes().ConvertType(CGM.getContext().LongTy);
846 // Now add the base class descriptions.
848 // Itanium C++ ABI 2.9.5p6c:
849 // __base_info[] is an array of base class descriptions -- one for every
850 // direct proper base. Each description is of the type:
852 // struct abi::__base_class_type_info {
854 // const __class_type_info *__base_type;
855 // long __offset_flags;
857 // enum __offset_flags_masks {
858 // __virtual_mask = 0x1,
859 // __public_mask = 0x2,
860 // __offset_shift = 8
863 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
864 E = RD->bases_end(); I != E; ++I) {
865 const CXXBaseSpecifier *Base = I;
867 // The __base_type member points to the RTTI for the base type.
868 Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(Base->getType()));
870 const CXXRecordDecl *BaseDecl =
871 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
873 int64_t OffsetFlags = 0;
875 // All but the lower 8 bits of __offset_flags are a signed offset.
876 // For a non-virtual base, this is the offset in the object of the base
877 // subobject. For a virtual base, this is the offset in the virtual table of
878 // the virtual base offset for the virtual base referenced (negative).
880 if (Base->isVirtual())
882 CGM.getVTables().getVirtualBaseOffsetOffset(RD, BaseDecl);
884 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
885 Offset = Layout.getBaseClassOffset(BaseDecl);
888 OffsetFlags = Offset.getQuantity() << 8;
890 // The low-order byte of __offset_flags contains flags, as given by the
891 // masks from the enumeration __offset_flags_masks.
892 if (Base->isVirtual())
893 OffsetFlags |= BCTI_Virtual;
894 if (Base->getAccessSpecifier() == AS_public)
895 OffsetFlags |= BCTI_Public;
897 Fields.push_back(llvm::ConstantInt::get(LongLTy, OffsetFlags));
901 /// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct,
902 /// used for pointer types.
903 void RTTIBuilder::BuildPointerTypeInfo(QualType PointeeTy) {
905 QualType UnqualifiedPointeeTy =
906 CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals);
908 // Itanium C++ ABI 2.9.5p7:
909 // __flags is a flag word describing the cv-qualification and other
910 // attributes of the type pointed to
911 unsigned Flags = ComputeQualifierFlags(Quals);
913 // Itanium C++ ABI 2.9.5p7:
914 // When the abi::__pbase_type_info is for a direct or indirect pointer to an
915 // incomplete class type, the incomplete target type flag is set.
916 if (ContainsIncompleteClassType(UnqualifiedPointeeTy))
917 Flags |= PTI_Incomplete;
919 const llvm::Type *UnsignedIntLTy =
920 CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
921 Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
923 // Itanium C++ ABI 2.9.5p7:
924 // __pointee is a pointer to the std::type_info derivation for the
925 // unqualified type being pointed to.
926 llvm::Constant *PointeeTypeInfo =
927 RTTIBuilder(CGM).BuildTypeInfo(UnqualifiedPointeeTy);
928 Fields.push_back(PointeeTypeInfo);
931 /// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info
932 /// struct, used for member pointer types.
933 void RTTIBuilder::BuildPointerToMemberTypeInfo(const MemberPointerType *Ty) {
934 QualType PointeeTy = Ty->getPointeeType();
937 QualType UnqualifiedPointeeTy =
938 CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals);
940 // Itanium C++ ABI 2.9.5p7:
941 // __flags is a flag word describing the cv-qualification and other
942 // attributes of the type pointed to.
943 unsigned Flags = ComputeQualifierFlags(Quals);
945 const RecordType *ClassType = cast<RecordType>(Ty->getClass());
947 // Itanium C++ ABI 2.9.5p7:
948 // When the abi::__pbase_type_info is for a direct or indirect pointer to an
949 // incomplete class type, the incomplete target type flag is set.
950 if (ContainsIncompleteClassType(UnqualifiedPointeeTy))
951 Flags |= PTI_Incomplete;
953 if (IsIncompleteClassType(ClassType))
954 Flags |= PTI_ContainingClassIncomplete;
956 const llvm::Type *UnsignedIntLTy =
957 CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
958 Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
960 // Itanium C++ ABI 2.9.5p7:
961 // __pointee is a pointer to the std::type_info derivation for the
962 // unqualified type being pointed to.
963 llvm::Constant *PointeeTypeInfo =
964 RTTIBuilder(CGM).BuildTypeInfo(UnqualifiedPointeeTy);
965 Fields.push_back(PointeeTypeInfo);
967 // Itanium C++ ABI 2.9.5p9:
968 // __context is a pointer to an abi::__class_type_info corresponding to the
969 // class type containing the member pointed to
970 // (e.g., the "A" in "int A::*").
971 Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(QualType(ClassType, 0)));
974 llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
976 // Return a bogus pointer if RTTI is disabled, unless it's for EH.
977 // FIXME: should we even be calling this method if RTTI is disabled
978 // and it's not for EH?
979 if (!ForEH && !getContext().getLangOptions().RTTI) {
980 const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
981 return llvm::Constant::getNullValue(Int8PtrTy);
984 if (ForEH && Ty->isObjCObjectPointerType() && !Features.NeXTRuntime) {
985 return Runtime->GetEHType(Ty);
988 return RTTIBuilder(*this).BuildTypeInfo(Ty);
991 void CodeGenModule::EmitFundamentalRTTIDescriptor(QualType Type) {
992 QualType PointerType = Context.getPointerType(Type);
993 QualType PointerTypeConst = Context.getPointerType(Type.withConst());
994 RTTIBuilder(*this).BuildTypeInfo(Type, true);
995 RTTIBuilder(*this).BuildTypeInfo(PointerType, true);
996 RTTIBuilder(*this).BuildTypeInfo(PointerTypeConst, true);
999 void CodeGenModule::EmitFundamentalRTTIDescriptors() {
1000 QualType FundamentalTypes[] = { Context.VoidTy, Context.NullPtrTy,
1001 Context.BoolTy, Context.WCharTy,
1002 Context.CharTy, Context.UnsignedCharTy,
1003 Context.SignedCharTy, Context.ShortTy,
1004 Context.UnsignedShortTy, Context.IntTy,
1005 Context.UnsignedIntTy, Context.LongTy,
1006 Context.UnsignedLongTy, Context.LongLongTy,
1007 Context.UnsignedLongLongTy, Context.FloatTy,
1008 Context.DoubleTy, Context.LongDoubleTy,
1009 Context.Char16Ty, Context.Char32Ty };
1010 for (unsigned i = 0; i < sizeof(FundamentalTypes)/sizeof(QualType); ++i)
1011 EmitFundamentalRTTIDescriptor(FundamentalTypes[i]);