void
ASTRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD,
const CXXRecordDecl *&FirstPrimary) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
assert(!i->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (!i->isVirtual()) {
SelectPrimaryVBase(Base, FirstPrimary);
if (PrimaryBase.getBase())
return;
continue;
}
if (IsNearlyEmpty(Base)) {
if (FirstPrimary==0)
FirstPrimary = Base;
if (!IndirectPrimaryBases.count(Base)) {
setPrimaryBase(Base, /*IsVirtual=*/true);
return;
}
}
assert(i->isVirtual());
SelectPrimaryVBase(Base, FirstPrimary);
if (PrimaryBase.getBase())
return;
}
}
void InheritanceHierarchyWriter::WriteNode(QualType Type, bool FromVirtual) {
QualType CanonType = Context.getCanonicalType(Type);
if (FromVirtual) {
if (KnownVirtualBases.find(CanonType) != KnownVirtualBases.end())
return;
// We haven't seen this virtual base before, so display it and
// its bases.
KnownVirtualBases.insert(CanonType);
}
// Declare the node itself.
Out << " ";
WriteNodeReference(Type, FromVirtual);
// Give the node a label based on the name of the class.
std::string TypeName = Type.getAsString();
Out << " [ shape=\"box\", label=\"" << DOT::EscapeString(TypeName);
// If the name of the class was a typedef or something different
// from the "real" class name, show the real class name in
// parentheses so we don't confuse ourselves.
if (TypeName != CanonType.getAsString()) {
Out << "\\n(" << CanonType.getAsString() << ")";
}
// Finished describing the node.
Out << " \"];\n";
// Display the base classes.
const CXXRecordDecl *Decl
= static_cast<const CXXRecordDecl *>(Type->getAs<RecordType>()->getDecl());
for (CXXRecordDecl::base_class_const_iterator Base = Decl->bases_begin();
Base != Decl->bases_end(); ++Base) {
QualType CanonBaseType = Context.getCanonicalType(Base->getType());
// If this is not virtual inheritance, bump the direct base
// count for the type.
if (!Base->isVirtual())
++DirectBaseCount[CanonBaseType];
// Write out the node (if we need to).
WriteNode(Base->getType(), Base->isVirtual());
// Write out the edge.
Out << " ";
WriteNodeReference(Type, FromVirtual);
Out << " -> ";
WriteNodeReference(Base->getType(), Base->isVirtual());
// Write out edge attributes to show the kind of inheritance.
if (Base->isVirtual()) {
Out << " [ style=\"dashed\" ]";
}
Out << ";";
}
}
/// LayoutVirtualBases - layout the non-virtual bases of a record decl.
bool
CGRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// We only want to lay out virtual bases that aren't indirect primary bases
// of some other base.
if (I->isVirtual() && !IndirectPrimaryBases.count(BaseDecl)) {
// Only lay out the base once.
if (!LaidOutVirtualBases.insert(BaseDecl))
continue;
CharUnits vbaseOffset = Layout.getVBaseClassOffset(BaseDecl);
if (!LayoutVirtualBase(BaseDecl, vbaseOffset))
return false;
}
if (!BaseDecl->getNumVBases()) {
// This base isn't interesting since it doesn't have any virtual bases.
continue;
}
if (!LayoutVirtualBases(BaseDecl, Layout))
return false;
}
return true;
}
bool
CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
// If we have a primary base, lay it out first.
if (PrimaryBase) {
if (!Layout.isPrimaryBaseVirtual()) {
if (!LayoutNonVirtualBase(PrimaryBase, CharUnits::Zero()))
return false;
} else {
if (!LayoutVirtualBase(PrimaryBase, CharUnits::Zero()))
return false;
}
// Otherwise, add a vtable / vf-table if the layout says to do so.
} else if (Layout.hasOwnVFPtr()) {
llvm::Type *FunctionType =
llvm::FunctionType::get(llvm::Type::getInt32Ty(Types.getLLVMContext()),
/*isVarArg=*/true);
llvm::Type *VTableTy = FunctionType->getPointerTo();
if (getTypeAlignment(VTableTy) > Alignment) {
// FIXME: Should we allow this to happen in Sema?
assert(!Packed && "Alignment is wrong even with packed struct!");
return false;
}
assert(NextFieldOffset.isZero() &&
"VTable pointer must come first!");
AppendField(CharUnits::Zero(), VTableTy->getPointerTo());
}
// Layout the non-virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// We've already laid out the primary base.
if (BaseDecl == PrimaryBase && !Layout.isPrimaryBaseVirtual())
continue;
if (!LayoutNonVirtualBase(BaseDecl, Layout.getBaseClassOffset(BaseDecl)))
return false;
}
// Add a vb-table pointer if the layout insists.
if (Layout.hasOwnVBPtr()) {
CharUnits VBPtrOffset = Layout.getVBPtrOffset();
llvm::Type *Vbptr = llvm::Type::getInt32PtrTy(Types.getLLVMContext());
AppendPadding(VBPtrOffset, getTypeAlignment(Vbptr));
AppendField(VBPtrOffset, Vbptr);
}
return true;
}
void ASTRecordLayoutBuilder::UpdateEmptyClassOffsets(const CXXRecordDecl *RD,
uint64_t Offset) {
if (RD->isEmpty())
EmptyClassOffsets.insert(std::make_pair(Offset, RD));
const ASTRecordLayout &Info = Ctx.getASTRecordLayout(RD);
// Update bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
assert(!I->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
if (I->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
uint64_t BaseClassOffset = Info.getBaseClassOffset(Base);
UpdateEmptyClassOffsets(Base, Offset + BaseClassOffset);
}
// Update fields.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
uint64_t FieldOffset = Info.getFieldOffset(FieldNo);
UpdateEmptyClassOffsets(FD, Offset + FieldOffset);
}
// FIXME: Update virtual bases.
}
void VTTBuilder::LayoutVirtualVTTs(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Check if this is a virtual base.
if (I->isVirtual()) {
// Check if we've seen this base before.
if (!VBases.insert(BaseDecl))
continue;
CharUnits BaseOffset =
MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/true);
}
// We only need to layout virtual VTTs for this base if it actually has
// virtual bases.
if (BaseDecl->getNumVBases())
LayoutVirtualVTTs(BaseDecl, VBases);
}
}
// 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 ASTRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
const CXXRecordDecl *PB,
int64_t Offset,
llvm::SmallSet<const CXXRecordDecl*, 32> &mark,
llvm::SmallSet<const CXXRecordDecl*, 32> &IndirectPrimary) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
#if 0
const ASTRecordLayout &L = Ctx.getASTRecordLayout(Base);
const CXXRecordDecl *PB = L.getPrimaryBase();
if (PB && L.getPrimaryBaseWasVirtual()
&& IndirectPrimary.count(PB)) {
int64_t BaseOffset;
// FIXME: calculate this.
BaseOffset = (1<<63) | (1<<31);
VBases.push_back(PB);
VBaseOffsets.push_back(BaseOffset);
}
#endif
int64_t BaseOffset = Offset;;
// FIXME: Calculate BaseOffset.
if (i->isVirtual()) {
if (Base == PB) {
// Only lay things out once.
if (mark.count(Base))
continue;
// Mark it so we don't lay it out twice.
mark.insert(Base);
assert (IndirectPrimary.count(Base) && "IndirectPrimary was wrong");
VBases.push_back(Base);
VBaseOffsets.push_back(Offset);
} else if (IndirectPrimary.count(Base)) {
// Someone else will eventually lay this out.
;
} else {
// Only lay things out once.
if (mark.count(Base))
continue;
// Mark it so we don't lay it out twice.
mark.insert(Base);
LayoutVirtualBase(Base);
BaseOffset = *(VBaseOffsets.end()-1);
}
}
if (Base->getNumVBases()) {
const ASTRecordLayout &L = Ctx.getASTRecordLayout(Base);
const CXXRecordDecl *PB = L.getPrimaryBase();
LayoutVirtualBases(Base, PB, BaseOffset, mark, IndirectPrimary);
}
}
}
void
ASTRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (!i->isVirtual()) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
// Skip the PrimaryBase here, as it is laid down first.
if (Base != PrimaryBase || PrimaryBaseWasVirtual)
LayoutBaseNonVirtually(Base, false);
}
}
}
void ASTRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *Class,
const CXXRecordDecl *RD,
const CXXRecordDecl *PB,
uint64_t Offset,
llvm::SmallSet<const CXXRecordDecl*, 32> &mark,
llvm::SmallSet<const CXXRecordDecl*, 32> &IndirectPrimary) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
assert(!i->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
uint64_t BaseOffset = Offset;
if (i->isVirtual()) {
if (Base == PB) {
// Only lay things out once.
if (mark.count(Base))
continue;
// Mark it so we don't lay it out twice.
mark.insert(Base);
assert (IndirectPrimary.count(Base) && "IndirectPrimary was wrong");
VBases.push_back(std::make_pair(Base, Offset));
} else if (IndirectPrimary.count(Base)) {
// Someone else will eventually lay this out.
;
} else {
// Only lay things out once.
if (mark.count(Base))
continue;
// Mark it so we don't lay it out twice.
mark.insert(Base);
LayoutVirtualBase(Base);
BaseOffset = VBases.back().second;
}
} else {
if (RD == Class)
BaseOffset = getBaseOffset(Base);
else {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
}
}
if (Base->getNumVBases()) {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Base);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBaseInfo().getBase();
LayoutVirtualBases(Class, Base, PrimaryBase, BaseOffset, mark,
IndirectPrimary);
}
}
}
void
ASTRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (!i->isVirtual()) {
assert(!i->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
// Skip the PrimaryBase here, as it is laid down first.
if (Base != PrimaryBase.getBase() || PrimaryBase.isVirtual())
LayoutBaseNonVirtually(Base, false);
}
}
}
/// SelectPrimaryBase - Selects the primary base for the given class and
/// record that with setPrimaryBase. We also calculate the IndirectPrimaries.
void ASTRecordLayoutBuilder::SelectPrimaryBase(const CXXRecordDecl *RD) {
// Compute all the primary virtual bases for all of our direct and
// indirect bases, and record all their primary virtual base classes.
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
assert(!i->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
IdentifyPrimaryBases(Base);
}
// If the record has a dynamic base class, attempt to choose a primary base
// class. It is the first (in direct base class order) non-virtual dynamic
// base class, if one exists.
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
// Ignore virtual bases.
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (Base->isDynamicClass()) {
// We found it.
PrimaryBase = ASTRecordLayout::PrimaryBaseInfo(Base, /*IsVirtual=*/false);
return;
}
}
// Otherwise, it is the first nearly empty virtual base that is not an
// indirect primary virtual base class, if one exists.
// If we have no virtual bases at this point, bail out as the searching below
// is expensive.
if (RD->getNumVBases() == 0)
return;
// Then we can search for the first nearly empty virtual base itself.
const CXXRecordDecl *FirstPrimary = 0;
SelectPrimaryVBase(RD, FirstPrimary);
// Otherwise if is the first nearly empty virtual base, if one exists,
// otherwise there is no primary base class.
if (!PrimaryBase.getBase())
setPrimaryBase(FirstPrimary, /*IsVirtual=*/true);
}
bool ASTRecordLayoutBuilder::canPlaceRecordAtOffset(const CXXRecordDecl *RD,
uint64_t Offset) const {
// Look for an empty class with the same type at the same offset.
for (EmptyClassOffsetsTy::const_iterator I =
EmptyClassOffsets.lower_bound(Offset),
E = EmptyClassOffsets.upper_bound(Offset); I != E; ++I) {
if (I->second == RD)
return false;
}
const ASTRecordLayout &Info = Ctx.getASTRecordLayout(RD);
// Check bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
assert(!I->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
if (I->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
uint64_t BaseClassOffset = Info.getBaseClassOffset(Base);
if (!canPlaceRecordAtOffset(Base, Offset + BaseClassOffset))
return false;
}
// Check fields.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
uint64_t FieldOffset = Info.getFieldOffset(FieldNo);
if (!canPlaceFieldAtOffset(FD, Offset + FieldOffset))
return false;
}
// FIXME: virtual bases.
return true;
}
/// SelectPrimaryBase - Selects the primary base for the given class and
/// record that with setPrimaryBase. We also calculate the IndirectPrimaries.
void ASTRecordLayoutBuilder::SelectPrimaryBase(const CXXRecordDecl *RD,
llvm::SmallSet<const CXXRecordDecl*, 32> &IndirectPrimary) {
// We compute all the primary virtual bases for all of our direct and
// indirect bases, and record all their primary virtual base classes.
const CXXRecordDecl *FirstPrimary = 0;
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
SelectPrimaryForBase(Base, IndirectPrimary);
}
// The primary base is the first non-virtual indirect or direct base class,
// if one exists.
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (!i->isVirtual()) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (Base->isDynamicClass()) {
setPrimaryBase(Base, false);
return;
}
}
}
setPrimaryBase(0, false);
// Otherwise, it is the first nearly empty virtual base that is not an
// indirect primary virtual base class, if one exists.
// If we have no virtual bases at this point, bail out as the searching below
// is expensive.
if (RD->getNumVBases() == 0)
return;
// Then we can search for the first nearly empty virtual base itself.
SelectPrimaryVBase(RD, FirstPrimary, IndirectPrimary);
// Otherwise if is the first nearly empty virtual base, if one exists,
// otherwise there is no primary base class.
setPrimaryBase(FirstPrimary, true);
return;
}
void VTTBuilder::LayoutSecondaryVTTs(BaseSubobject Base) {
const CXXRecordDecl *RD = Base.getBase();
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Don't layout virtual bases.
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
CharUnits BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
// Layout the VTT for this base.
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/false);
}
}
void ASTRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD,
const CXXRecordDecl *&FirstPrimary,
llvm::SmallSet<const CXXRecordDecl*, 32> &IndirectPrimary) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (!i->isVirtual()) {
SelectPrimaryVBase(Base, FirstPrimary, IndirectPrimary);
if (PrimaryBase)
return;
continue;
}
if (IsNearlyEmpty(Base)) {
if (FirstPrimary==0)
FirstPrimary = Base;
if (!IndirectPrimary.count(Base)) {
setPrimaryBase(Base, true);
return;
}
}
}
}
void
VTTBuilder::LayoutSecondaryVirtualPointers(BaseSubobject Base,
bool BaseIsMorallyVirtual,
uint64_t VTableIndex,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy &VBases) {
const CXXRecordDecl *RD = Base.getBase();
// We're not interested in bases that don't have virtual bases, and not
// morally virtual bases.
if (!RD->getNumVBases() && !BaseIsMorallyVirtual)
return;
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers are present for all bases with either
// virtual bases or virtual function declarations overridden along a
// virtual path.
//
// If the base class is not dynamic, we don't want to add it, nor any
// of its base classes.
if (!BaseDecl->isDynamicClass())
continue;
bool BaseDeclIsMorallyVirtual = BaseIsMorallyVirtual;
bool BaseDeclIsNonVirtualPrimaryBase = false;
CharUnits BaseOffset;
if (I->isVirtual()) {
// Ignore virtual bases that we've already visited.
if (!VBases.insert(BaseDecl))
continue;
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
BaseDeclIsMorallyVirtual = true;
} else {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
if (!Layout.isPrimaryBaseVirtual() &&
Layout.getPrimaryBase() == BaseDecl)
BaseDeclIsNonVirtualPrimaryBase = true;
}
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers: for each base class X which (a) has virtual
// bases or is reachable along a virtual path from D, and (b) is not a
// non-virtual primary base, the address of the virtual table for X-in-D
// or an appropriate construction virtual table.
if (!BaseDeclIsNonVirtualPrimaryBase &&
(BaseDecl->getNumVBases() || BaseDeclIsMorallyVirtual)) {
// Add the vtable pointer.
AddVTablePointer(BaseSubobject(BaseDecl, BaseOffset), VTableIndex,
VTableClass);
}
// And lay out the secondary virtual pointers for the base class.
LayoutSecondaryVirtualPointers(BaseSubobject(BaseDecl, BaseOffset),
BaseDeclIsMorallyVirtual, VTableIndex,
VTableClass, VBases);
}
}
/// Try to emit a base destructor as an alias to its primary
/// base-class destructor.
bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
if (!getCodeGenOpts().CXXCtorDtorAliases)
return true;
// Producing an alias to a base class ctor/dtor can degrade debug quality
// as the debugger cannot tell them apart.
if (getCodeGenOpts().OptimizationLevel == 0)
return true;
// If the destructor doesn't have a trivial body, we have to emit it
// separately.
if (!D->hasTrivialBody())
return true;
const CXXRecordDecl *Class = D->getParent();
// If we need to manipulate a VTT parameter, give up.
if (Class->getNumVBases()) {
// Extra Credit: passing extra parameters is perfectly safe
// in many calling conventions, so only bail out if the ctor's
// calling convention is nonstandard.
return true;
}
// If any field has a non-trivial destructor, we have to emit the
// destructor separately.
for (CXXRecordDecl::field_iterator I = Class->field_begin(),
E = Class->field_end(); I != E; ++I)
if (I->getType().isDestructedType())
return true;
// Try to find a unique base class with a non-trivial destructor.
const CXXRecordDecl *UniqueBase = 0;
for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(),
E = Class->bases_end(); I != E; ++I) {
// We're in the base destructor, so skip virtual bases.
if (I->isVirtual()) continue;
// Skip base classes with trivial destructors.
const CXXRecordDecl *Base
= cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
if (Base->hasTrivialDestructor()) continue;
// If we've already found a base class with a non-trivial
// destructor, give up.
if (UniqueBase) return true;
UniqueBase = Base;
}
// If we didn't find any bases with a non-trivial destructor, then
// the base destructor is actually effectively trivial, which can
// happen if it was needlessly user-defined or if there are virtual
// bases with non-trivial destructors.
if (!UniqueBase)
return true;
// If the base is at a non-zero offset, give up.
const ASTRecordLayout &ClassLayout = Context.getASTRecordLayout(Class);
if (!ClassLayout.getBaseClassOffset(UniqueBase).isZero())
return true;
const CXXDestructorDecl *BaseD = UniqueBase->getDestructor();
return TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Base),
GlobalDecl(BaseD, Dtor_Base),
false);
}
/// Try to emit a base destructor as an alias to its primary
/// base-class destructor.
bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
if (!getCodeGenOpts().CXXCtorDtorAliases)
return true;
// If the destructor doesn't have a trivial body, we have to emit it
// separately.
if (!HasTrivialBody(D))
return true;
const CXXRecordDecl *Class = D->getParent();
// If we need to manipulate a VTT parameter, give up.
if (Class->getNumVBases()) {
// Extra Credit: passing extra parameters is perfectly safe
// in many calling conventions, so only bail out if the ctor's
// calling convention is nonstandard.
return true;
}
// If any fields have a non-trivial destructor, we have to emit it
// separately.
for (CXXRecordDecl::field_iterator I = Class->field_begin(),
E = Class->field_end(); I != E; ++I)
if (const RecordType *RT = (*I)->getType()->getAs<RecordType>())
if (!cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor())
return true;
// Try to find a unique base class with a non-trivial destructor.
const CXXRecordDecl *UniqueBase = 0;
for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(),
E = Class->bases_end(); I != E; ++I) {
// We're in the base destructor, so skip virtual bases.
if (I->isVirtual()) continue;
// Skip base classes with trivial destructors.
const CXXRecordDecl *Base
= cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
if (Base->hasTrivialDestructor()) continue;
// If we've already found a base class with a non-trivial
// destructor, give up.
if (UniqueBase) return true;
UniqueBase = Base;
}
// If we didn't find any bases with a non-trivial destructor, then
// the base destructor is actually effectively trivial, which can
// happen if it was needlessly user-defined or if there are virtual
// bases with non-trivial destructors.
if (!UniqueBase)
return true;
/// If we don't have a definition for the destructor yet, don't
/// emit. We can't emit aliases to declarations; that's just not
/// how aliases work.
const CXXDestructorDecl *BaseD = UniqueBase->getDestructor(getContext());
if (!BaseD->isImplicit() && !BaseD->getBody())
return true;
// If the base is at a non-zero offset, give up.
const ASTRecordLayout &ClassLayout = Context.getASTRecordLayout(Class);
if (ClassLayout.getBaseClassOffset(UniqueBase) != 0)
return true;
return TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Base),
GlobalDecl(BaseD, Dtor_Base));
}
bool CXXBasePaths::lookupInBases(ASTContext &Context,
const CXXRecordDecl *Record,
CXXRecordDecl::BaseMatchesCallback *BaseMatches,
void *UserData) {
bool FoundPath = false;
// The access of the path down to this record.
AccessSpecifier AccessToHere = ScratchPath.Access;
bool IsFirstStep = ScratchPath.empty();
for (CXXRecordDecl::base_class_const_iterator BaseSpec = Record->bases_begin(),
BaseSpecEnd = Record->bases_end();
BaseSpec != BaseSpecEnd;
++BaseSpec) {
// Find the record of the base class subobjects for this type.
QualType BaseType = Context.getCanonicalType(BaseSpec->getType())
.getUnqualifiedType();
// C++ [temp.dep]p3:
// In the definition of a class template or a member of a class template,
// if a base class of the class template depends on a template-parameter,
// the base class scope is not examined during unqualified name lookup
// either at the point of definition of the class template or member or
// during an instantiation of the class tem- plate or member.
if (BaseType->isDependentType())
continue;
// Determine whether we need to visit this base class at all,
// updating the count of subobjects appropriately.
std::pair<bool, unsigned>& Subobjects = ClassSubobjects[BaseType];
bool VisitBase = true;
bool SetVirtual = false;
if (BaseSpec->isVirtual()) {
VisitBase = !Subobjects.first;
Subobjects.first = true;
if (isDetectingVirtual() && DetectedVirtual == 0) {
// If this is the first virtual we find, remember it. If it turns out
// there is no base path here, we'll reset it later.
DetectedVirtual = BaseType->getAs<RecordType>();
SetVirtual = true;
}
} else
++Subobjects.second;
if (isRecordingPaths()) {
// Add this base specifier to the current path.
CXXBasePathElement Element;
Element.Base = &*BaseSpec;
Element.Class = Record;
if (BaseSpec->isVirtual())
Element.SubobjectNumber = 0;
else
Element.SubobjectNumber = Subobjects.second;
ScratchPath.push_back(Element);
// Calculate the "top-down" access to this base class.
// The spec actually describes this bottom-up, but top-down is
// equivalent because the definition works out as follows:
// 1. Write down the access along each step in the inheritance
// chain, followed by the access of the decl itself.
// For example, in
// class A { public: int foo; };
// class B : protected A {};
// class C : public B {};
// class D : private C {};
// we would write:
// private public protected public
// 2. If 'private' appears anywhere except far-left, access is denied.
// 3. Otherwise, overall access is determined by the most restrictive
// access in the sequence.
if (IsFirstStep)
ScratchPath.Access = BaseSpec->getAccessSpecifier();
else
ScratchPath.Access = CXXRecordDecl::MergeAccess(AccessToHere,
BaseSpec->getAccessSpecifier());
}
// Track whether there's a path involving this specific base.
bool FoundPathThroughBase = false;
if (BaseMatches(BaseSpec, ScratchPath, UserData)) {
// We've found a path that terminates at this base.
FoundPath = FoundPathThroughBase = true;
if (isRecordingPaths()) {
// We have a path. Make a copy of it before moving on.
Paths.push_back(ScratchPath);
} else if (!isFindingAmbiguities()) {
// We found a path and we don't care about ambiguities;
// return immediately.
return FoundPath;
}
} else if (VisitBase) {
CXXRecordDecl *BaseRecord
= cast<CXXRecordDecl>(BaseSpec->getType()->castAs<RecordType>()
->getDecl());
if (lookupInBases(Context, BaseRecord, BaseMatches, UserData)) {
// C++ [class.member.lookup]p2:
// A member name f in one sub-object B hides a member name f in
// a sub-object A if A is a base class sub-object of B. Any
// declarations that are so hidden are eliminated from
// consideration.
// There is a path to a base class that meets the criteria. If we're
// not collecting paths or finding ambiguities, we're done.
FoundPath = FoundPathThroughBase = true;
if (!isFindingAmbiguities())
return FoundPath;
}
}
// Pop this base specifier off the current path (if we're
// collecting paths).
if (isRecordingPaths()) {
ScratchPath.pop_back();
}
// If we set a virtual earlier, and this isn't a path, forget it again.
if (SetVirtual && !FoundPathThroughBase) {
DetectedVirtual = 0;
}
}
// Reset the scratch path access.
ScratchPath.Access = AccessToHere;
return FoundPath;
}
void FinalOverriderCollector::Collect(const CXXRecordDecl *RD,
bool VirtualBase,
const CXXRecordDecl *InVirtualSubobject,
CXXFinalOverriderMap &Overriders) {
unsigned SubobjectNumber = 0;
if (!VirtualBase)
SubobjectNumber
= ++SubobjectCount[cast<CXXRecordDecl>(RD->getCanonicalDecl())];
for (CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin(),
BaseEnd = RD->bases_end(); Base != BaseEnd; ++Base) {
if (const RecordType *RT = Base->getType()->getAs<RecordType>()) {
const CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!BaseDecl->isPolymorphic())
continue;
if (Overriders.empty() && !Base->isVirtual()) {
// There are no other overriders of virtual member functions,
// so let the base class fill in our overriders for us.
Collect(BaseDecl, false, InVirtualSubobject, Overriders);
continue;
}
// Collect all of the overridders from the base class subobject
// and merge them into the set of overridders for this class.
// For virtual base classes, populate or use the cached virtual
// overrides so that we do not walk the virtual base class (and
// its base classes) more than once.
CXXFinalOverriderMap ComputedBaseOverriders;
CXXFinalOverriderMap *BaseOverriders = &ComputedBaseOverriders;
if (Base->isVirtual()) {
CXXFinalOverriderMap *&MyVirtualOverriders = VirtualOverriders[BaseDecl];
BaseOverriders = MyVirtualOverriders;
if (!MyVirtualOverriders) {
MyVirtualOverriders = new CXXFinalOverriderMap;
// Collect may cause VirtualOverriders to reallocate, invalidating the
// MyVirtualOverriders reference. Set BaseOverriders to the right
// value now.
BaseOverriders = MyVirtualOverriders;
Collect(BaseDecl, true, BaseDecl, *MyVirtualOverriders);
}
} else
Collect(BaseDecl, false, InVirtualSubobject, ComputedBaseOverriders);
// Merge the overriders from this base class into our own set of
// overriders.
for (CXXFinalOverriderMap::iterator OM = BaseOverriders->begin(),
OMEnd = BaseOverriders->end();
OM != OMEnd;
++OM) {
const CXXMethodDecl *CanonOM
= cast<CXXMethodDecl>(OM->first->getCanonicalDecl());
Overriders[CanonOM].add(OM->second);
}
}
}
for (CXXRecordDecl::method_iterator M = RD->method_begin(),
MEnd = RD->method_end();
M != MEnd;
++M) {
// We only care about virtual methods.
if (!M->isVirtual())
continue;
CXXMethodDecl *CanonM = cast<CXXMethodDecl>(M->getCanonicalDecl());
if (CanonM->begin_overridden_methods()
== CanonM->end_overridden_methods()) {
// This is a new virtual function that does not override any
// other virtual function. Add it to the map of virtual
// functions for which we are tracking overridders.
// C++ [class.virtual]p2:
// For convenience we say that any virtual function overrides itself.
Overriders[CanonM].add(SubobjectNumber,
UniqueVirtualMethod(CanonM, SubobjectNumber,
InVirtualSubobject));
continue;
}
// This virtual method overrides other virtual methods, so it does
// not add any new slots into the set of overriders. Instead, we
// replace entries in the set of overriders with the new
// overrider. To do so, we dig down to the original virtual
// functions using data recursion and update all of the methods it
// overrides.
typedef std::pair<CXXMethodDecl::method_iterator,
CXXMethodDecl::method_iterator> OverriddenMethods;
SmallVector<OverriddenMethods, 4> Stack;
Stack.push_back(std::make_pair(CanonM->begin_overridden_methods(),
CanonM->end_overridden_methods()));
while (!Stack.empty()) {
OverriddenMethods OverMethods = Stack.back();
Stack.pop_back();
for (; OverMethods.first != OverMethods.second; ++OverMethods.first) {
const CXXMethodDecl *CanonOM
= cast<CXXMethodDecl>((*OverMethods.first)->getCanonicalDecl());
// C++ [class.virtual]p2:
// A virtual member function C::vf of a class object S is
// a final overrider unless the most derived class (1.8)
// of which S is a base class subobject (if any) declares
// or inherits another member function that overrides vf.
//
// Treating this object like the most derived class, we
// replace any overrides from base classes with this
// overriding virtual function.
Overriders[CanonOM].replaceAll(
UniqueVirtualMethod(CanonM, SubobjectNumber,
InVirtualSubobject));
if (CanonOM->begin_overridden_methods()
== CanonOM->end_overridden_methods())
continue;
// Continue recursion to the methods that this virtual method
// overrides.
Stack.push_back(std::make_pair(CanonOM->begin_overridden_methods(),
CanonOM->end_overridden_methods()));
}
}
// C++ [class.virtual]p2:
// For convenience we say that any virtual function overrides itself.
Overriders[CanonM].add(SubobjectNumber,
UniqueVirtualMethod(CanonM, SubobjectNumber,
InVirtualSubobject));
}
}
/// ConvertTagDeclType - Lay out a tagged decl type like struct or union or
/// enum.
const llvm::Type *CodeGenTypes::ConvertTagDeclType(const TagDecl *TD) {
// TagDecl's are not necessarily unique, instead use the (clang)
// type connected to the decl.
const Type *Key =
Context.getTagDeclType(TD).getTypePtr();
llvm::DenseMap<const Type*, llvm::PATypeHolder>::iterator TDTI =
TagDeclTypes.find(Key);
// If we've already compiled this tag type, use the previous definition.
if (TDTI != TagDeclTypes.end())
return TDTI->second;
const EnumDecl *ED = dyn_cast<EnumDecl>(TD);
// If this is still a forward declaration, just define an opaque
// type to use for this tagged decl.
// C++0x: If this is a enumeration type with fixed underlying type,
// consider it complete.
if (!TD->isDefinition() && !(ED && ED->isFixed())) {
llvm::Type *ResultType = llvm::OpaqueType::get(getLLVMContext());
TagDeclTypes.insert(std::make_pair(Key, ResultType));
return ResultType;
}
// Okay, this is a definition of a type. Compile the implementation now.
if (ED) // Don't bother storing enums in TagDeclTypes.
return ConvertTypeRecursive(ED->getIntegerType());
// This decl could well be recursive. In this case, insert an opaque
// definition of this type, which the recursive uses will get. We will then
// refine this opaque version later.
// Create new OpaqueType now for later use in case this is a recursive
// type. This will later be refined to the actual type.
llvm::PATypeHolder ResultHolder = llvm::OpaqueType::get(getLLVMContext());
TagDeclTypes.insert(std::make_pair(Key, ResultHolder));
const RecordDecl *RD = cast<const RecordDecl>(TD);
// Force conversion of non-virtual base classes recursively.
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(TD)) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (!i->isVirtual()) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
ConvertTagDeclType(Base);
}
}
}
// Layout fields.
CGRecordLayout *Layout = ComputeRecordLayout(RD);
CGRecordLayouts[Key] = Layout;
const llvm::Type *ResultType = Layout->getLLVMType();
// Refine our Opaque type to ResultType. This can invalidate ResultType, so
// make sure to read the result out of the holder.
cast<llvm::OpaqueType>(ResultHolder.get())
->refineAbstractTypeTo(ResultType);
return ResultHolder.get();
}
/// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) {
// TagDecl's are not necessarily unique, instead use the (clang)
// type connected to the decl.
const Type *Key = Context.getTagDeclType(RD).getTypePtr();
llvm::StructType *&Entry = RecordDeclTypes[Key];
// If we don't have a StructType at all yet, create the forward declaration.
if (Entry == 0) {
Entry = llvm::StructType::create(getLLVMContext());
addRecordTypeName(RD, Entry, "");
}
llvm::StructType *Ty = Entry;
// If this is still a forward declaration, or the LLVM type is already
// complete, there's nothing more to do.
RD = RD->getDefinition();
if (RD == 0 || !RD->isCompleteDefinition() || !Ty->isOpaque())
return Ty;
// If converting this type would cause us to infinitely loop, don't do it!
if (!isSafeToConvert(RD, *this)) {
DeferredRecords.push_back(RD);
return Ty;
}
// Okay, this is a definition of a type. Compile the implementation now.
bool InsertResult = RecordsBeingLaidOut.insert(Key); (void)InsertResult;
assert(InsertResult && "Recursively compiling a struct?");
// Force conversion of non-virtual base classes recursively.
if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
for (CXXRecordDecl::base_class_const_iterator i = CRD->bases_begin(),
e = CRD->bases_end(); i != e; ++i) {
if (i->isVirtual()) continue;
ConvertRecordDeclType(i->getType()->getAs<RecordType>()->getDecl());
}
}
// Layout fields.
CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty);
CGRecordLayouts[Key] = Layout;
// We're done laying out this struct.
bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult;
assert(EraseResult && "struct not in RecordsBeingLaidOut set?");
// If this struct blocked a FunctionType conversion, then recompute whatever
// was derived from that.
// FIXME: This is hugely overconservative.
if (SkippedLayout)
TypeCache.clear();
// If we're done converting the outer-most record, then convert any deferred
// structs as well.
if (RecordsBeingLaidOut.empty())
while (!DeferredRecords.empty())
ConvertRecordDeclType(DeferredRecords.pop_back_val());
return Ty;
}
void VBTableBuilder::findUnambiguousPaths(const CXXRecordDecl *ReusingBase,
BaseSubobject CurSubobject,
VBTablePathVector &Paths) {
size_t PathsStart = Paths.size();
bool ReuseVBPtrFromBase = true;
const CXXRecordDecl *CurBase = CurSubobject.getBase();
// If this base has a vbptr, then we've found a path. These are not full
// paths, so we don't use CXXBasePath.
if (hasVBPtr(CurBase)) {
ReuseVBPtrFromBase = false;
VBTablePath *Info = new VBTablePath(
VBTableInfo(ReusingBase, CurSubobject, /*GV=*/0));
Paths.push_back(Info);
}
// Recurse onto any bases which themselves have virtual bases.
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(CurBase);
for (CXXRecordDecl::base_class_const_iterator I = CurBase->bases_begin(),
E = CurBase->bases_end(); I != E; ++I) {
const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
if (!Base->getNumVBases())
continue; // Bases without virtual bases have no vbptrs.
CharUnits NextOffset;
const CXXRecordDecl *NextReusingBase = Base;
if (I->isVirtual()) {
if (!VBasesSeen.insert(Base))
continue; // Don't visit virtual bases twice.
NextOffset = DerivedLayout.getVBaseClassOffset(Base);
} else {
NextOffset = (CurSubobject.getBaseOffset() +
Layout.getBaseClassOffset(Base));
// If CurBase didn't have a vbptr, then ReusingBase will reuse the vbptr
// from the first non-virtual base with vbases for its vbptr.
if (ReuseVBPtrFromBase) {
NextReusingBase = ReusingBase;
ReuseVBPtrFromBase = false;
}
}
size_t NumPaths = Paths.size();
findUnambiguousPaths(NextReusingBase, BaseSubobject(Base, NextOffset),
Paths);
// Tag paths through this base with the base itself. We might use it to
// disambiguate.
for (size_t I = NumPaths, E = Paths.size(); I != E; ++I)
Paths[I]->NextBase = Base;
}
bool AmbiguousPaths = rebucketPaths(Paths, PathsStart);
if (AmbiguousPaths)
rebucketPaths(Paths, PathsStart, /*SecondPass=*/true);
#ifndef NDEBUG
// Check that the paths are in fact unique.
for (size_t I = PathsStart + 1, E = Paths.size(); I != E; ++I) {
assert(Paths[I]->Path != Paths[I - 1]->Path && "vbtable paths are not unique");
}
#endif
}
