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freebsd-nq/contrib/llvm/tools/clang/lib/CodeGen/CGRTTI.cpp
Dimitry Andric f785676f2a Upgrade our copy of llvm/clang to 3.4 release. This version supports 
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC after:	1 month
2014-02-16 19:44:07 +00:00

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//===--- CGCXXRTTI.cpp - Emit LLVM Code for C++ RTTI descriptors ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with C++ code generation of RTTI descriptors.
//
//===----------------------------------------------------------------------===//
#include "CodeGenModule.h"
#include "CGCXXABI.h"
#include "CGObjCRuntime.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/Type.h"
#include "clang/Frontend/CodeGenOptions.h"
using namespace clang;
using namespace CodeGen;
namespace {
class RTTIBuilder {
CodeGenModule &CGM; // Per-module state.
llvm::LLVMContext &VMContext;
/// Fields - The fields of the RTTI descriptor currently being built.
SmallVector<llvm::Constant *, 16> Fields;
/// GetAddrOfTypeName - Returns the mangled type name of the given type.
llvm::GlobalVariable *
GetAddrOfTypeName(QualType Ty, llvm::GlobalVariable::LinkageTypes Linkage);
/// GetAddrOfExternalRTTIDescriptor - Returns the constant for the RTTI
/// descriptor of the given type.
llvm::Constant *GetAddrOfExternalRTTIDescriptor(QualType Ty);
/// BuildVTablePointer - Build the vtable pointer for the given type.
void BuildVTablePointer(const Type *Ty);
/// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
/// inheritance, according to the Itanium C++ ABI, 2.9.5p6b.
void BuildSIClassTypeInfo(const CXXRecordDecl *RD);
/// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
/// classes with bases that do not satisfy the abi::__si_class_type_info
/// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
void BuildVMIClassTypeInfo(const CXXRecordDecl *RD);
/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, used
/// for pointer types.
void BuildPointerTypeInfo(QualType PointeeTy);
/// BuildObjCObjectTypeInfo - Build the appropriate kind of
/// type_info for an object type.
void BuildObjCObjectTypeInfo(const ObjCObjectType *Ty);
/// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info
/// struct, used for member pointer types.
void BuildPointerToMemberTypeInfo(const MemberPointerType *Ty);
public:
RTTIBuilder(CodeGenModule &CGM) : CGM(CGM),
VMContext(CGM.getModule().getContext()) { }
// Pointer type info flags.
enum {
/// PTI_Const - Type has const qualifier.
PTI_Const = 0x1,
/// PTI_Volatile - Type has volatile qualifier.
PTI_Volatile = 0x2,
/// PTI_Restrict - Type has restrict qualifier.
PTI_Restrict = 0x4,
/// PTI_Incomplete - Type is incomplete.
PTI_Incomplete = 0x8,
/// PTI_ContainingClassIncomplete - Containing class is incomplete.
/// (in pointer to member).
PTI_ContainingClassIncomplete = 0x10
};
// VMI type info flags.
enum {
/// VMI_NonDiamondRepeat - Class has non-diamond repeated inheritance.
VMI_NonDiamondRepeat = 0x1,
/// VMI_DiamondShaped - Class is diamond shaped.
VMI_DiamondShaped = 0x2
};
// Base class type info flags.
enum {
/// BCTI_Virtual - Base class is virtual.
BCTI_Virtual = 0x1,
/// BCTI_Public - Base class is public.
BCTI_Public = 0x2
};
/// BuildTypeInfo - Build the RTTI type info struct for the given type.
///
/// \param Force - true to force the creation of this RTTI value
llvm::Constant *BuildTypeInfo(QualType Ty, bool Force = false);
};
}
llvm::GlobalVariable *
RTTIBuilder::GetAddrOfTypeName(QualType Ty,
llvm::GlobalVariable::LinkageTypes Linkage) {
SmallString<256> OutName;
llvm::raw_svector_ostream Out(OutName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(Ty, Out);
Out.flush();
StringRef Name = OutName.str();
// We know that the mangled name of the type starts at index 4 of the
// mangled name of the typename, so we can just index into it in order to
// get the mangled name of the type.
llvm::Constant *Init = llvm::ConstantDataArray::getString(VMContext,
Name.substr(4));
llvm::GlobalVariable *GV =
CGM.CreateOrReplaceCXXRuntimeVariable(Name, Init->getType(), Linkage);
GV->setInitializer(Init);
return GV;
}
llvm::Constant *RTTIBuilder::GetAddrOfExternalRTTIDescriptor(QualType Ty) {
// Mangle the RTTI name.
SmallString<256> OutName;
llvm::raw_svector_ostream Out(OutName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out);
Out.flush();
StringRef Name = OutName.str();
// Look for an existing global.
llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name);
if (!GV) {
// Create a new global variable.
GV = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
/*Constant=*/true,
llvm::GlobalValue::ExternalLinkage, 0, Name);
}
return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
}
/// TypeInfoIsInStandardLibrary - Given a builtin type, returns whether the type
/// info for that type is defined in the standard library.
static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) {
// Itanium C++ ABI 2.9.2:
// Basic type information (e.g. for "int", "bool", etc.) will be kept in
// the run-time support library. Specifically, the run-time support
// library should contain type_info objects for the types X, X* and
// X const*, for every X in: void, std::nullptr_t, bool, wchar_t, char,
// unsigned char, signed char, short, unsigned short, int, unsigned int,
// long, unsigned long, long long, unsigned long long, float, double,
// long double, char16_t, char32_t, and the IEEE 754r decimal and
// half-precision floating point types.
switch (Ty->getKind()) {
case BuiltinType::Void:
case BuiltinType::NullPtr:
case BuiltinType::Bool:
case BuiltinType::WChar_S:
case BuiltinType::WChar_U:
case BuiltinType::Char_U:
case BuiltinType::Char_S:
case BuiltinType::UChar:
case BuiltinType::SChar:
case BuiltinType::Short:
case BuiltinType::UShort:
case BuiltinType::Int:
case BuiltinType::UInt:
case BuiltinType::Long:
case BuiltinType::ULong:
case BuiltinType::LongLong:
case BuiltinType::ULongLong:
case BuiltinType::Half:
case BuiltinType::Float:
case BuiltinType::Double:
case BuiltinType::LongDouble:
case BuiltinType::Char16:
case BuiltinType::Char32:
case BuiltinType::Int128:
case BuiltinType::UInt128:
case BuiltinType::OCLImage1d:
case BuiltinType::OCLImage1dArray:
case BuiltinType::OCLImage1dBuffer:
case BuiltinType::OCLImage2d:
case BuiltinType::OCLImage2dArray:
case BuiltinType::OCLImage3d:
case BuiltinType::OCLSampler:
case BuiltinType::OCLEvent:
return true;
case BuiltinType::Dependent:
#define BUILTIN_TYPE(Id, SingletonId)
#define PLACEHOLDER_TYPE(Id, SingletonId) \
case BuiltinType::Id:
#include "clang/AST/BuiltinTypes.def"
llvm_unreachable("asking for RRTI for a placeholder type!");
case BuiltinType::ObjCId:
case BuiltinType::ObjCClass:
case BuiltinType::ObjCSel:
llvm_unreachable("FIXME: Objective-C types are unsupported!");
}
llvm_unreachable("Invalid BuiltinType Kind!");
}
static bool TypeInfoIsInStandardLibrary(const PointerType *PointerTy) {
QualType PointeeTy = PointerTy->getPointeeType();
const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(PointeeTy);
if (!BuiltinTy)
return false;
// Check the qualifiers.
Qualifiers Quals = PointeeTy.getQualifiers();
Quals.removeConst();
if (!Quals.empty())
return false;
return TypeInfoIsInStandardLibrary(BuiltinTy);
}
/// IsStandardLibraryRTTIDescriptor - Returns whether the type
/// information for the given type exists in the standard library.
static bool IsStandardLibraryRTTIDescriptor(QualType Ty) {
// Type info for builtin types is defined in the standard library.
if (const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(Ty))
return TypeInfoIsInStandardLibrary(BuiltinTy);
// Type info for some pointer types to builtin types is defined in the
// standard library.
if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
return TypeInfoIsInStandardLibrary(PointerTy);
return false;
}
/// ShouldUseExternalRTTIDescriptor - Returns whether the type information for
/// the given type exists somewhere else, and that we should not emit the type
/// information in this translation unit. Assumes that it is not a
/// standard-library type.
static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM,
QualType Ty) {
ASTContext &Context = CGM.getContext();
// If RTTI is disabled, assume it might be disabled in the
// translation unit that defines any potential key function, too.
if (!Context.getLangOpts().RTTI) return false;
if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl());
if (!RD->hasDefinition())
return false;
if (!RD->isDynamicClass())
return false;
// FIXME: this may need to be reconsidered if the key function
// changes.
return CGM.getVTables().isVTableExternal(RD);
}
return false;
}
/// IsIncompleteClassType - Returns whether the given record type is incomplete.
static bool IsIncompleteClassType(const RecordType *RecordTy) {
return !RecordTy->getDecl()->isCompleteDefinition();
}
/// ContainsIncompleteClassType - Returns whether the given type contains an
/// incomplete class type. This is true if
///
/// * The given type is an incomplete class type.
/// * The given type is a pointer type whose pointee type contains an
/// incomplete class type.
/// * The given type is a member pointer type whose class is an incomplete
/// class type.
/// * The given type is a member pointer type whoise pointee type contains an
/// incomplete class type.
/// is an indirect or direct pointer to an incomplete class type.
static bool ContainsIncompleteClassType(QualType Ty) {
if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
if (IsIncompleteClassType(RecordTy))
return true;
}
if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
return ContainsIncompleteClassType(PointerTy->getPointeeType());
if (const MemberPointerType *MemberPointerTy =
dyn_cast<MemberPointerType>(Ty)) {
// Check if the class type is incomplete.
const RecordType *ClassType = cast<RecordType>(MemberPointerTy->getClass());
if (IsIncompleteClassType(ClassType))
return true;
return ContainsIncompleteClassType(MemberPointerTy->getPointeeType());
}
return false;
}
/// getTypeInfoLinkage - Return the linkage that the type info and type info
/// name constants should have for the given type.
static llvm::GlobalVariable::LinkageTypes
getTypeInfoLinkage(CodeGenModule &CGM, QualType Ty) {
// Itanium C++ ABI 2.9.5p7:
// In addition, it and all of the intermediate abi::__pointer_type_info
// structs in the chain down to the abi::__class_type_info for the
// incomplete class type must be prevented from resolving to the
// corresponding type_info structs for the complete class type, possibly
// by making them local static objects. Finally, a dummy class RTTI is
// generated for the incomplete type that will not resolve to the final
// complete class RTTI (because the latter need not exist), possibly by
// making it a local static object.
if (ContainsIncompleteClassType(Ty))
return llvm::GlobalValue::InternalLinkage;
switch (Ty->getLinkage()) {
case NoLinkage:
case VisibleNoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return llvm::GlobalValue::InternalLinkage;
case ExternalLinkage:
if (!CGM.getLangOpts().RTTI) {
// RTTI is not enabled, which means that this type info struct is going
// to be used for exception handling. Give it linkonce_odr linkage.
return llvm::GlobalValue::LinkOnceODRLinkage;
}
if (const RecordType *Record = dyn_cast<RecordType>(Ty)) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
if (RD->hasAttr<WeakAttr>())
return llvm::GlobalValue::WeakODRLinkage;
if (RD->isDynamicClass())
return CGM.getVTableLinkage(RD);
}
return llvm::GlobalValue::LinkOnceODRLinkage;
}
llvm_unreachable("Invalid linkage!");
}
// CanUseSingleInheritance - Return whether the given record decl has a "single,
// public, non-virtual base at offset zero (i.e. the derived class is dynamic
// iff the base is)", according to Itanium C++ ABI, 2.95p6b.
static bool CanUseSingleInheritance(const CXXRecordDecl *RD) {
// Check the number of bases.
if (RD->getNumBases() != 1)
return false;
// Get the base.
CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin();
// Check that the base is not virtual.
if (Base->isVirtual())
return false;
// Check that the base is public.
if (Base->getAccessSpecifier() != AS_public)
return false;
// Check that the class is dynamic iff the base is.
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
if (!BaseDecl->isEmpty() &&
BaseDecl->isDynamicClass() != RD->isDynamicClass())
return false;
return true;
}
void RTTIBuilder::BuildVTablePointer(const Type *Ty) {
// abi::__class_type_info.
static const char * const ClassTypeInfo =
"_ZTVN10__cxxabiv117__class_type_infoE";
// abi::__si_class_type_info.
static const char * const SIClassTypeInfo =
"_ZTVN10__cxxabiv120__si_class_type_infoE";
// abi::__vmi_class_type_info.
static const char * const VMIClassTypeInfo =
"_ZTVN10__cxxabiv121__vmi_class_type_infoE";
const char *VTableName = 0;
switch (Ty->getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#include "clang/AST/TypeNodes.def"
llvm_unreachable("Non-canonical and dependent types shouldn't get here");
case Type::LValueReference:
case Type::RValueReference:
llvm_unreachable("References shouldn't get here");
case Type::Auto:
llvm_unreachable("Undeduced auto type shouldn't get here");
case Type::Builtin:
// GCC treats vector and complex types as fundamental types.
case Type::Vector:
case Type::ExtVector:
case Type::Complex:
case Type::Atomic:
// FIXME: GCC treats block pointers as fundamental types?!
case Type::BlockPointer:
// abi::__fundamental_type_info.
VTableName = "_ZTVN10__cxxabiv123__fundamental_type_infoE";
break;
case Type::ConstantArray:
case Type::IncompleteArray:
case Type::VariableArray:
// abi::__array_type_info.
VTableName = "_ZTVN10__cxxabiv117__array_type_infoE";
break;
case Type::FunctionNoProto:
case Type::FunctionProto:
// abi::__function_type_info.
VTableName = "_ZTVN10__cxxabiv120__function_type_infoE";
break;
case Type::Enum:
// abi::__enum_type_info.
VTableName = "_ZTVN10__cxxabiv116__enum_type_infoE";
break;
case Type::Record: {
const CXXRecordDecl *RD =
cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
if (!RD->hasDefinition() || !RD->getNumBases()) {
VTableName = ClassTypeInfo;
} else if (CanUseSingleInheritance(RD)) {
VTableName = SIClassTypeInfo;
} else {
VTableName = VMIClassTypeInfo;
}
break;
}
case Type::ObjCObject:
// Ignore protocol qualifiers.
Ty = cast<ObjCObjectType>(Ty)->getBaseType().getTypePtr();
// Handle id and Class.
if (isa<BuiltinType>(Ty)) {
VTableName = ClassTypeInfo;
break;
}
assert(isa<ObjCInterfaceType>(Ty));
// Fall through.
case Type::ObjCInterface:
if (cast<ObjCInterfaceType>(Ty)->getDecl()->getSuperClass()) {
VTableName = SIClassTypeInfo;
} else {
VTableName = ClassTypeInfo;
}
break;
case Type::ObjCObjectPointer:
case Type::Pointer:
// abi::__pointer_type_info.
VTableName = "_ZTVN10__cxxabiv119__pointer_type_infoE";
break;
case Type::MemberPointer:
// abi::__pointer_to_member_type_info.
VTableName = "_ZTVN10__cxxabiv129__pointer_to_member_type_infoE";
break;
}
llvm::Constant *VTable =
CGM.getModule().getOrInsertGlobal(VTableName, CGM.Int8PtrTy);
llvm::Type *PtrDiffTy =
CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
// The vtable address point is 2.
llvm::Constant *Two = llvm::ConstantInt::get(PtrDiffTy, 2);
VTable = llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, Two);
VTable = llvm::ConstantExpr::getBitCast(VTable, CGM.Int8PtrTy);
Fields.push_back(VTable);
}
llvm::Constant *RTTIBuilder::BuildTypeInfo(QualType Ty, bool Force) {
// We want to operate on the canonical type.
Ty = CGM.getContext().getCanonicalType(Ty);
// Check if we've already emitted an RTTI descriptor for this type.
SmallString<256> OutName;
llvm::raw_svector_ostream Out(OutName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty, Out);
Out.flush();
StringRef Name = OutName.str();
llvm::GlobalVariable *OldGV = CGM.getModule().getNamedGlobal(Name);
if (OldGV && !OldGV->isDeclaration()) {
assert(!OldGV->hasAvailableExternallyLinkage() &&
"available_externally typeinfos not yet implemented");
return llvm::ConstantExpr::getBitCast(OldGV, CGM.Int8PtrTy);
}
// Check if there is already an external RTTI descriptor for this type.
bool IsStdLib = IsStandardLibraryRTTIDescriptor(Ty);
if (!Force && (IsStdLib || ShouldUseExternalRTTIDescriptor(CGM, Ty)))
return GetAddrOfExternalRTTIDescriptor(Ty);
// Emit the standard library with external linkage.
llvm::GlobalVariable::LinkageTypes Linkage;
if (IsStdLib)
Linkage = llvm::GlobalValue::ExternalLinkage;
else
Linkage = getTypeInfoLinkage(CGM, Ty);
// Add the vtable pointer.
BuildVTablePointer(cast<Type>(Ty));
// And the name.
llvm::GlobalVariable *TypeName = GetAddrOfTypeName(Ty, Linkage);
Fields.push_back(llvm::ConstantExpr::getBitCast(TypeName, CGM.Int8PtrTy));
switch (Ty->getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#include "clang/AST/TypeNodes.def"
llvm_unreachable("Non-canonical and dependent types shouldn't get here");
// GCC treats vector types as fundamental types.
case Type::Builtin:
case Type::Vector:
case Type::ExtVector:
case Type::Complex:
case Type::BlockPointer:
// Itanium C++ ABI 2.9.5p4:
// abi::__fundamental_type_info adds no data members to std::type_info.
break;
case Type::LValueReference:
case Type::RValueReference:
llvm_unreachable("References shouldn't get here");
case Type::Auto:
llvm_unreachable("Undeduced auto type shouldn't get here");
case Type::ConstantArray:
case Type::IncompleteArray:
case Type::VariableArray:
// Itanium C++ ABI 2.9.5p5:
// abi::__array_type_info adds no data members to std::type_info.
break;
case Type::FunctionNoProto:
case Type::FunctionProto:
// Itanium C++ ABI 2.9.5p5:
// abi::__function_type_info adds no data members to std::type_info.
break;
case Type::Enum:
// Itanium C++ ABI 2.9.5p5:
// abi::__enum_type_info adds no data members to std::type_info.
break;
case Type::Record: {
const CXXRecordDecl *RD =
cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
if (!RD->hasDefinition() || !RD->getNumBases()) {
// We don't need to emit any fields.
break;
}
if (CanUseSingleInheritance(RD))
BuildSIClassTypeInfo(RD);
else
BuildVMIClassTypeInfo(RD);
break;
}
case Type::ObjCObject:
case Type::ObjCInterface:
BuildObjCObjectTypeInfo(cast<ObjCObjectType>(Ty));
break;
case Type::ObjCObjectPointer:
BuildPointerTypeInfo(cast<ObjCObjectPointerType>(Ty)->getPointeeType());
break;
case Type::Pointer:
BuildPointerTypeInfo(cast<PointerType>(Ty)->getPointeeType());
break;
case Type::MemberPointer:
BuildPointerToMemberTypeInfo(cast<MemberPointerType>(Ty));
break;
case Type::Atomic:
// No fields, at least for the moment.
break;
}
llvm::Constant *Init = llvm::ConstantStruct::getAnon(Fields);
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
/*Constant=*/true, Linkage, Init, Name);
// If there's already an old global variable, replace it with the new one.
if (OldGV) {
GV->takeName(OldGV);
llvm::Constant *NewPtr =
llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
OldGV->replaceAllUsesWith(NewPtr);
OldGV->eraseFromParent();
}
// GCC only relies on the uniqueness of the type names, not the
// type_infos themselves, so we can emit these as hidden symbols.
// But don't do this if we're worried about strict visibility
// compatibility.
if (const RecordType *RT = dyn_cast<RecordType>(Ty)) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
CGM.setTypeVisibility(GV, RD, CodeGenModule::TVK_ForRTTI);
CGM.setTypeVisibility(TypeName, RD, CodeGenModule::TVK_ForRTTIName);
} else {
Visibility TypeInfoVisibility = DefaultVisibility;
if (CGM.getCodeGenOpts().HiddenWeakVTables &&
Linkage == llvm::GlobalValue::LinkOnceODRLinkage)
TypeInfoVisibility = HiddenVisibility;
// The type name should have the same visibility as the type itself.
Visibility ExplicitVisibility = Ty->getVisibility();
TypeName->setVisibility(CodeGenModule::
GetLLVMVisibility(ExplicitVisibility));
TypeInfoVisibility = minVisibility(TypeInfoVisibility, Ty->getVisibility());
GV->setVisibility(CodeGenModule::GetLLVMVisibility(TypeInfoVisibility));
}
GV->setUnnamedAddr(true);
return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
}
/// ComputeQualifierFlags - Compute the pointer type info flags from the
/// given qualifier.
static unsigned ComputeQualifierFlags(Qualifiers Quals) {
unsigned Flags = 0;
if (Quals.hasConst())
Flags |= RTTIBuilder::PTI_Const;
if (Quals.hasVolatile())
Flags |= RTTIBuilder::PTI_Volatile;
if (Quals.hasRestrict())
Flags |= RTTIBuilder::PTI_Restrict;
return Flags;
}
/// BuildObjCObjectTypeInfo - Build the appropriate kind of type_info
/// for the given Objective-C object type.
void RTTIBuilder::BuildObjCObjectTypeInfo(const ObjCObjectType *OT) {
// Drop qualifiers.
const Type *T = OT->getBaseType().getTypePtr();
assert(isa<BuiltinType>(T) || isa<ObjCInterfaceType>(T));
// The builtin types are abi::__class_type_infos and don't require
// extra fields.
if (isa<BuiltinType>(T)) return;
ObjCInterfaceDecl *Class = cast<ObjCInterfaceType>(T)->getDecl();
ObjCInterfaceDecl *Super = Class->getSuperClass();
// Root classes are also __class_type_info.
if (!Super) return;
QualType SuperTy = CGM.getContext().getObjCInterfaceType(Super);
// Everything else is single inheritance.
llvm::Constant *BaseTypeInfo = RTTIBuilder(CGM).BuildTypeInfo(SuperTy);
Fields.push_back(BaseTypeInfo);
}
/// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
/// inheritance, according to the Itanium C++ ABI, 2.95p6b.
void RTTIBuilder::BuildSIClassTypeInfo(const CXXRecordDecl *RD) {
// Itanium C++ ABI 2.9.5p6b:
// It adds to abi::__class_type_info a single member pointing to the
// type_info structure for the base type,
llvm::Constant *BaseTypeInfo =
RTTIBuilder(CGM).BuildTypeInfo(RD->bases_begin()->getType());
Fields.push_back(BaseTypeInfo);
}
namespace {
/// SeenBases - Contains virtual and non-virtual bases seen when traversing
/// a class hierarchy.
struct SeenBases {
llvm::SmallPtrSet<const CXXRecordDecl *, 16> NonVirtualBases;
llvm::SmallPtrSet<const CXXRecordDecl *, 16> VirtualBases;
};
}
/// ComputeVMIClassTypeInfoFlags - Compute the value of the flags member in
/// abi::__vmi_class_type_info.
///
static unsigned ComputeVMIClassTypeInfoFlags(const CXXBaseSpecifier *Base,
SeenBases &Bases) {
unsigned Flags = 0;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
if (Base->isVirtual()) {
// Mark the virtual base as seen.
if (!Bases.VirtualBases.insert(BaseDecl)) {
// If this virtual base has been seen before, then the class is diamond
// shaped.
Flags |= RTTIBuilder::VMI_DiamondShaped;
} else {
if (Bases.NonVirtualBases.count(BaseDecl))
Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
}
} else {
// Mark the non-virtual base as seen.
if (!Bases.NonVirtualBases.insert(BaseDecl)) {
// If this non-virtual base has been seen before, then the class has non-
// diamond shaped repeated inheritance.
Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
} else {
if (Bases.VirtualBases.count(BaseDecl))
Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
}
}
// Walk all bases.
for (CXXRecordDecl::base_class_const_iterator I = BaseDecl->bases_begin(),
E = BaseDecl->bases_end(); I != E; ++I)
Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
return Flags;
}
static unsigned ComputeVMIClassTypeInfoFlags(const CXXRecordDecl *RD) {
unsigned Flags = 0;
SeenBases Bases;
// Walk all bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I)
Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
return Flags;
}
/// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
/// classes with bases that do not satisfy the abi::__si_class_type_info
/// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
void RTTIBuilder::BuildVMIClassTypeInfo(const CXXRecordDecl *RD) {
llvm::Type *UnsignedIntLTy =
CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
// Itanium C++ ABI 2.9.5p6c:
// __flags is a word with flags describing details about the class
// structure, which may be referenced by using the __flags_masks
// enumeration. These flags refer to both direct and indirect bases.
unsigned Flags = ComputeVMIClassTypeInfoFlags(RD);
Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
// Itanium C++ ABI 2.9.5p6c:
// __base_count is a word with the number of direct proper base class
// descriptions that follow.
Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, RD->getNumBases()));
if (!RD->getNumBases())
return;
llvm::Type *LongLTy =
CGM.getTypes().ConvertType(CGM.getContext().LongTy);
// Now add the base class descriptions.
// Itanium C++ ABI 2.9.5p6c:
// __base_info[] is an array of base class descriptions -- one for every
// direct proper base. Each description is of the type:
//
// struct abi::__base_class_type_info {
// public:
// const __class_type_info *__base_type;
// long __offset_flags;
//
// enum __offset_flags_masks {
// __virtual_mask = 0x1,
// __public_mask = 0x2,
// __offset_shift = 8
// };
// };
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXBaseSpecifier *Base = I;
// The __base_type member points to the RTTI for the base type.
Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(Base->getType()));
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
int64_t OffsetFlags = 0;
// All but the lower 8 bits of __offset_flags are a signed offset.
// For a non-virtual base, this is the offset in the object of the base
// subobject. For a virtual base, this is the offset in the virtual table of
// the virtual base offset for the virtual base referenced (negative).
CharUnits Offset;
if (Base->isVirtual())
Offset =
CGM.getItaniumVTableContext().getVirtualBaseOffsetOffset(RD, BaseDecl);
else {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
Offset = Layout.getBaseClassOffset(BaseDecl);
};
OffsetFlags = uint64_t(Offset.getQuantity()) << 8;
// The low-order byte of __offset_flags contains flags, as given by the
// masks from the enumeration __offset_flags_masks.
if (Base->isVirtual())
OffsetFlags |= BCTI_Virtual;
if (Base->getAccessSpecifier() == AS_public)
OffsetFlags |= BCTI_Public;
Fields.push_back(llvm::ConstantInt::get(LongLTy, OffsetFlags));
}
}
/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct,
/// used for pointer types.
void RTTIBuilder::BuildPointerTypeInfo(QualType PointeeTy) {
Qualifiers Quals;
QualType UnqualifiedPointeeTy =
CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals);
// Itanium C++ ABI 2.9.5p7:
// __flags is a flag word describing the cv-qualification and other
// attributes of the type pointed to
unsigned Flags = ComputeQualifierFlags(Quals);
// Itanium C++ ABI 2.9.5p7:
// When the abi::__pbase_type_info is for a direct or indirect pointer to an
// incomplete class type, the incomplete target type flag is set.
if (ContainsIncompleteClassType(UnqualifiedPointeeTy))
Flags |= PTI_Incomplete;
llvm::Type *UnsignedIntLTy =
CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
// Itanium C++ ABI 2.9.5p7:
// __pointee is a pointer to the std::type_info derivation for the
// unqualified type being pointed to.
llvm::Constant *PointeeTypeInfo =
RTTIBuilder(CGM).BuildTypeInfo(UnqualifiedPointeeTy);
Fields.push_back(PointeeTypeInfo);
}
/// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info
/// struct, used for member pointer types.
void RTTIBuilder::BuildPointerToMemberTypeInfo(const MemberPointerType *Ty) {
QualType PointeeTy = Ty->getPointeeType();
Qualifiers Quals;
QualType UnqualifiedPointeeTy =
CGM.getContext().getUnqualifiedArrayType(PointeeTy, Quals);
// Itanium C++ ABI 2.9.5p7:
// __flags is a flag word describing the cv-qualification and other
// attributes of the type pointed to.
unsigned Flags = ComputeQualifierFlags(Quals);
const RecordType *ClassType = cast<RecordType>(Ty->getClass());
// Itanium C++ ABI 2.9.5p7:
// When the abi::__pbase_type_info is for a direct or indirect pointer to an
// incomplete class type, the incomplete target type flag is set.
if (ContainsIncompleteClassType(UnqualifiedPointeeTy))
Flags |= PTI_Incomplete;
if (IsIncompleteClassType(ClassType))
Flags |= PTI_ContainingClassIncomplete;
llvm::Type *UnsignedIntLTy =
CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
// Itanium C++ ABI 2.9.5p7:
// __pointee is a pointer to the std::type_info derivation for the
// unqualified type being pointed to.
llvm::Constant *PointeeTypeInfo =
RTTIBuilder(CGM).BuildTypeInfo(UnqualifiedPointeeTy);
Fields.push_back(PointeeTypeInfo);
// Itanium C++ ABI 2.9.5p9:
// __context is a pointer to an abi::__class_type_info corresponding to the
// class type containing the member pointed to
// (e.g., the "A" in "int A::*").
Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(QualType(ClassType, 0)));
}
llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
bool ForEH) {
// Return a bogus pointer if RTTI is disabled, unless it's for EH.
// FIXME: should we even be calling this method if RTTI is disabled
// and it's not for EH?
if (!ForEH && !getLangOpts().RTTI)
return llvm::Constant::getNullValue(Int8PtrTy);
if (ForEH && Ty->isObjCObjectPointerType() &&
LangOpts.ObjCRuntime.isGNUFamily())
return ObjCRuntime->GetEHType(Ty);
return RTTIBuilder(*this).BuildTypeInfo(Ty);
}
void CodeGenModule::EmitFundamentalRTTIDescriptor(QualType Type) {
QualType PointerType = Context.getPointerType(Type);
QualType PointerTypeConst = Context.getPointerType(Type.withConst());
RTTIBuilder(*this).BuildTypeInfo(Type, true);
RTTIBuilder(*this).BuildTypeInfo(PointerType, true);
RTTIBuilder(*this).BuildTypeInfo(PointerTypeConst, true);
}
void CodeGenModule::EmitFundamentalRTTIDescriptors() {
QualType FundamentalTypes[] = { Context.VoidTy, Context.NullPtrTy,
Context.BoolTy, Context.WCharTy,
Context.CharTy, Context.UnsignedCharTy,
Context.SignedCharTy, Context.ShortTy,
Context.UnsignedShortTy, Context.IntTy,
Context.UnsignedIntTy, Context.LongTy,
Context.UnsignedLongTy, Context.LongLongTy,
Context.UnsignedLongLongTy, Context.FloatTy,
Context.DoubleTy, Context.LongDoubleTy,
Context.Char16Ty, Context.Char32Ty };
for (unsigned i = 0; i < llvm::array_lengthof(FundamentalTypes); ++i)
EmitFundamentalRTTIDescriptor(FundamentalTypes[i]);
}
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