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gerrit-public.fairphone.software / fp2-dev / platform / external / clang / ab8bbf4ebd3e3e6eab913cb044772a62b7581941 / . / lib / CodeGen / CGVtable.cpp
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//===--- CGVtable.cpp - Emit LLVM Code for C++ vtables --------------------===//
//
// 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 virtual tables.
//
//===----------------------------------------------------------------------===//
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
#include "llvm/ADT/DenseSet.h"
#include <cstdio>
using namespace clang;
using namespace CodeGen;
namespace {
class VtableBuilder {
public:
/// Index_t - Vtable index type.
typedef uint64_t Index_t;
typedef std::vector<std::pair<GlobalDecl,
std::pair<GlobalDecl, ThunkAdjustment> > >
SavedAdjustmentsVectorTy;
private:
// VtableComponents - The components of the vtable being built.
typedef llvm::SmallVector<llvm::Constant *, 64> VtableComponentsVectorTy;
VtableComponentsVectorTy VtableComponents;
const bool BuildVtable;
llvm::Type *Ptr8Ty;
/// MostDerivedClass - The most derived class that this vtable is being
/// built for.
const CXXRecordDecl *MostDerivedClass;
/// LayoutClass - The most derived class used for virtual base layout
/// information.
const CXXRecordDecl *LayoutClass;
/// LayoutOffset - The offset for Class in LayoutClass.
uint64_t LayoutOffset;
/// BLayout - Layout for the most derived class that this vtable is being
/// built for.
const ASTRecordLayout &BLayout;
llvm::SmallSet<const CXXRecordDecl *, 32> IndirectPrimary;
llvm::SmallSet<const CXXRecordDecl *, 32> SeenVBase;
llvm::Constant *rtti;
llvm::LLVMContext &VMContext;
CodeGenModule &CGM; // Per-module state.
llvm::DenseMap<GlobalDecl, Index_t> VCall;
llvm::DenseMap<GlobalDecl, Index_t> VCallOffset;
// This is the offset to the nearest virtual base
llvm::DenseMap<GlobalDecl, Index_t> NonVirtualOffset;
llvm::DenseMap<const CXXRecordDecl *, Index_t> VBIndex;
/// PureVirtualFunction - Points to __cxa_pure_virtual.
llvm::Constant *PureVirtualFn;
/// VtableMethods - A data structure for keeping track of methods in a vtable.
/// Can add methods, override methods and iterate in vtable order.
class VtableMethods {
// MethodToIndexMap - Maps from a global decl to the index it has in the
// Methods vector.
llvm::DenseMap<GlobalDecl, uint64_t> MethodToIndexMap;
/// Methods - The methods, in vtable order.
typedef llvm::SmallVector<GlobalDecl, 16> MethodsVectorTy;
MethodsVectorTy Methods;
MethodsVectorTy OrigMethods;
public:
/// AddMethod - Add a method to the vtable methods.
void AddMethod(GlobalDecl GD) {
assert(!MethodToIndexMap.count(GD) &&
"Method has already been added!");
MethodToIndexMap[GD] = Methods.size();
Methods.push_back(GD);
OrigMethods.push_back(GD);
}
/// OverrideMethod - Replace a method with another.
void OverrideMethod(GlobalDecl OverriddenGD, GlobalDecl GD) {
llvm::DenseMap<GlobalDecl, uint64_t>::iterator i
= MethodToIndexMap.find(OverriddenGD);
assert(i != MethodToIndexMap.end() && "Did not find entry!");
// Get the index of the old decl.
uint64_t Index = i->second;
// Replace the old decl with the new decl.
Methods[Index] = GD;
// And add the new.
MethodToIndexMap[GD] = Index;
}
/// getIndex - Gives the index of a passed in GlobalDecl. Returns false if
/// the index couldn't be found.
bool getIndex(GlobalDecl GD, uint64_t &Index) const {
llvm::DenseMap<GlobalDecl, uint64_t>::const_iterator i
= MethodToIndexMap.find(GD);
if (i == MethodToIndexMap.end())
return false;
Index = i->second;
return true;
}
GlobalDecl getOrigMethod(uint64_t Index) const {
return OrigMethods[Index];
}
MethodsVectorTy::size_type size() const {
return Methods.size();
}
void clear() {
MethodToIndexMap.clear();
Methods.clear();
OrigMethods.clear();
}
GlobalDecl operator[](uint64_t Index) const {
return Methods[Index];
}
};
/// Methods - The vtable methods we're currently building.
VtableMethods Methods;
/// ThisAdjustments - For a given index in the vtable, contains the 'this'
/// pointer adjustment needed for a method.
typedef llvm::DenseMap<uint64_t, ThunkAdjustment> ThisAdjustmentsMapTy;
ThisAdjustmentsMapTy ThisAdjustments;
SavedAdjustmentsVectorTy SavedAdjustments;
/// BaseReturnTypes - Contains the base return types of methods who have been
/// overridden with methods whose return types require adjustment. Used for
/// generating covariant thunk information.
typedef llvm::DenseMap<uint64_t, CanQualType> BaseReturnTypesMapTy;
BaseReturnTypesMapTy BaseReturnTypes;
std::vector<Index_t> VCalls;
typedef std::pair<const CXXRecordDecl *, uint64_t> CtorVtable_t;
// subAddressPoints - Used to hold the AddressPoints (offsets) into the built
// vtable for use in computing the initializers for the VTT.
llvm::DenseMap<CtorVtable_t, int64_t> &subAddressPoints;
/// AddressPoints - Address points for this vtable.
CGVtableInfo::AddressPointsMapTy& AddressPoints;
typedef CXXRecordDecl::method_iterator method_iter;
const uint32_t LLVMPointerWidth;
Index_t extra;
typedef std::vector<std::pair<const CXXRecordDecl *, int64_t> > Path_t;
static llvm::DenseMap<CtorVtable_t, int64_t>&
AllocAddressPoint(CodeGenModule &cgm, const CXXRecordDecl *l,
const CXXRecordDecl *c) {
CGVtableInfo::AddrMap_t *&oref = cgm.getVtableInfo().AddressPoints[l];
if (oref == 0)
oref = new CGVtableInfo::AddrMap_t;
llvm::DenseMap<CtorVtable_t, int64_t> *&ref = (*oref)[c];
if (ref == 0)
ref = new llvm::DenseMap<CtorVtable_t, int64_t>;
return *ref;
}
/// getPureVirtualFn - Return the __cxa_pure_virtual function.
llvm::Constant* getPureVirtualFn() {
if (!PureVirtualFn) {
const llvm::FunctionType *Ty =
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
/*isVarArg=*/false);
PureVirtualFn = wrap(CGM.CreateRuntimeFunction(Ty, "__cxa_pure_virtual"));
}
return PureVirtualFn;
}
public:
VtableBuilder(const CXXRecordDecl *MostDerivedClass,
const CXXRecordDecl *l, uint64_t lo, CodeGenModule &cgm,
bool build, CGVtableInfo::AddressPointsMapTy& AddressPoints)
: BuildVtable(build), MostDerivedClass(MostDerivedClass), LayoutClass(l),
LayoutOffset(lo), BLayout(cgm.getContext().getASTRecordLayout(l)),
rtti(0), VMContext(cgm.getModule().getContext()),CGM(cgm),
PureVirtualFn(0),
subAddressPoints(AllocAddressPoint(cgm, l, MostDerivedClass)),
AddressPoints(AddressPoints),
LLVMPointerWidth(cgm.getContext().Target.getPointerWidth(0))
{
Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
if (BuildVtable) {
QualType ClassType = CGM.getContext().getTagDeclType(MostDerivedClass);
rtti = CGM.GetAddrOfRTTIDescriptor(ClassType);
}
}
// getVtableComponents - Returns a reference to the vtable components.
const VtableComponentsVectorTy &getVtableComponents() const {
return VtableComponents;
}
llvm::DenseMap<const CXXRecordDecl *, uint64_t> &getVBIndex()
{ return VBIndex; }
SavedAdjustmentsVectorTy &getSavedAdjustments()
{ return SavedAdjustments; }
llvm::Constant *wrap(Index_t i) {
llvm::Constant *m;
m = llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), i);
return llvm::ConstantExpr::getIntToPtr(m, Ptr8Ty);
}
llvm::Constant *wrap(llvm::Constant *m) {
return llvm::ConstantExpr::getBitCast(m, Ptr8Ty);
}
#define D1(x)
//#define D1(X) do { if (getenv("DEBUG")) { X; } } while (0)
void GenerateVBaseOffsets(const CXXRecordDecl *RD, uint64_t Offset,
bool updateVBIndex, Index_t current_vbindex) {
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());
Index_t next_vbindex = current_vbindex;
if (i->isVirtual() && !SeenVBase.count(Base)) {
SeenVBase.insert(Base);
if (updateVBIndex) {
next_vbindex = (ssize_t)(-(VCalls.size()*LLVMPointerWidth/8)
- 3*LLVMPointerWidth/8);
VBIndex[Base] = next_vbindex;
}
int64_t BaseOffset = -(Offset/8) + BLayout.getVBaseClassOffset(Base)/8;
VCalls.push_back((0?700:0) + BaseOffset);
D1(printf(" vbase for %s at %d delta %d most derived %s\n",
Base->getNameAsCString(),
(int)-VCalls.size()-3, (int)BaseOffset,
Class->getNameAsCString()));
}
// We also record offsets for non-virtual bases to closest enclosing
// virtual base. We do this so that we don't have to search
// for the nearst virtual base class when generating thunks.
if (updateVBIndex && VBIndex.count(Base) == 0)
VBIndex[Base] = next_vbindex;
GenerateVBaseOffsets(Base, Offset, updateVBIndex, next_vbindex);
}
}
void StartNewTable() {
SeenVBase.clear();
}
Index_t getNVOffset_1(const CXXRecordDecl *D, const CXXRecordDecl *B,
Index_t Offset = 0) {
if (B == D)
return Offset;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(D);
for (CXXRecordDecl::base_class_const_iterator i = D->bases_begin(),
e = D->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
int64_t BaseOffset = 0;
if (!i->isVirtual())
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
int64_t o = getNVOffset_1(Base, B, BaseOffset);
if (o >= 0)
return o;
}
return -1;
}
/// getNVOffset - Returns the non-virtual offset for the given (B) base of the
/// derived class D.
Index_t getNVOffset(QualType qB, QualType qD) {
qD = qD->getPointeeType();
qB = qB->getPointeeType();
CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
int64_t o = getNVOffset_1(D, B);
if (o >= 0)
return o;
assert(false && "FIXME: non-virtual base not found");
return 0;
}
/// getVbaseOffset - Returns the index into the vtable for the virtual base
/// offset for the given (B) virtual base of the derived class D.
Index_t getVbaseOffset(QualType qB, QualType qD) {
qD = qD->getPointeeType();
qB = qB->getPointeeType();
CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
if (D != MostDerivedClass)
return CGM.getVtableInfo().getVirtualBaseOffsetIndex(D, B);
llvm::DenseMap<const CXXRecordDecl *, Index_t>::iterator i;
i = VBIndex.find(B);
if (i != VBIndex.end())
return i->second;
assert(false && "FIXME: Base not found");
return 0;
}
bool OverrideMethod(GlobalDecl GD, bool MorallyVirtual,
Index_t OverrideOffset, Index_t Offset,
int64_t CurrentVBaseOffset);
/// AppendMethods - Append the current methods to the vtable.
void AppendMethodsToVtable();
llvm::Constant *WrapAddrOf(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const llvm::Type *Ty = CGM.getTypes().GetFunctionTypeForVtable(MD);
return wrap(CGM.GetAddrOfFunction(GD, Ty));
}
void OverrideMethods(Path_t *Path, bool MorallyVirtual, int64_t Offset,
int64_t CurrentVBaseOffset) {
for (Path_t::reverse_iterator i = Path->rbegin(),
e = Path->rend(); i != e; ++i) {
const CXXRecordDecl *RD = i->first;
int64_t OverrideOffset = i->second;
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi) {
const CXXMethodDecl *MD = *mi;
if (!MD->isVirtual())
continue;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
// Override both the complete and the deleting destructor.
GlobalDecl CompDtor(DD, Dtor_Complete);
OverrideMethod(CompDtor, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
GlobalDecl DeletingDtor(DD, Dtor_Deleting);
OverrideMethod(DeletingDtor, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
} else {
OverrideMethod(MD, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
}
}
}
}
void AddMethod(const GlobalDecl GD, bool MorallyVirtual, Index_t Offset,
int64_t CurrentVBaseOffset) {
// If we can find a previously allocated slot for this, reuse it.
if (OverrideMethod(GD, MorallyVirtual, Offset, Offset,
CurrentVBaseOffset))
return;
// We didn't find an entry in the vtable that we could use, add a new
// entry.
Methods.AddMethod(GD);
D1(printf(" vfn for %s at %d\n", MD->getNameAsString().c_str(),
(int)Index[GD]));
VCallOffset[GD] = Offset/8;
if (MorallyVirtual) {
Index_t &idx = VCall[GD];
// Allocate the first one, after that, we reuse the previous one.
if (idx == 0) {
NonVirtualOffset[GD] = CurrentVBaseOffset/8 - Offset/8;
idx = VCalls.size()+1;
VCalls.push_back(0);
D1(printf(" vcall for %s at %d with delta %d\n",
MD->getNameAsString().c_str(), (int)-VCalls.size()-3, 0));
}
}
}
void AddMethods(const CXXRecordDecl *RD, bool MorallyVirtual,
Index_t Offset, int64_t CurrentVBaseOffset) {
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi) {
const CXXMethodDecl *MD = *mi;
if (!MD->isVirtual())
continue;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
// For destructors, add both the complete and the deleting destructor
// to the vtable.
AddMethod(GlobalDecl(DD, Dtor_Complete), MorallyVirtual, Offset,
CurrentVBaseOffset);
AddMethod(GlobalDecl(DD, Dtor_Deleting), MorallyVirtual, Offset,
CurrentVBaseOffset);
} else
AddMethod(MD, MorallyVirtual, Offset, CurrentVBaseOffset);
}
}
void NonVirtualBases(const CXXRecordDecl *RD, const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase,
bool PrimaryBaseWasVirtual, bool MorallyVirtual,
int64_t Offset, int64_t CurrentVBaseOffset,
Path_t *Path) {
Path->push_back(std::make_pair(RD, Offset));
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (Base != PrimaryBase || PrimaryBaseWasVirtual) {
uint64_t o = Offset + Layout.getBaseClassOffset(Base);
StartNewTable();
GenerateVtableForBase(Base, o, MorallyVirtual, false,
CurrentVBaseOffset, Path);
}
}
Path->pop_back();
}
// #define D(X) do { X; } while (0)
#define D(X)
void insertVCalls(int InsertionPoint) {
D1(printf("============= combining vbase/vcall\n"));
D(VCalls.insert(VCalls.begin(), 673));
D(VCalls.push_back(672));
VtableComponents.insert(VtableComponents.begin() + InsertionPoint,
VCalls.size(), 0);
if (BuildVtable) {
// The vcalls come first...
for (std::vector<Index_t>::reverse_iterator i = VCalls.rbegin(),
e = VCalls.rend();
i != e; ++i)
VtableComponents[InsertionPoint++] = wrap((0?600:0) + *i);
}
VCalls.clear();
VCall.clear();
}
void AddAddressPoints(const CXXRecordDecl *RD, uint64_t Offset,
Index_t AddressPoint) {
D1(printf("XXX address point for %s in %s layout %s at offset %d is %d\n",
RD->getNameAsCString(), Class->getNameAsCString(),
LayoutClass->getNameAsCString(), (int)Offset, (int)AddressPoint));
subAddressPoints[std::make_pair(RD, Offset)] = AddressPoint;
AddressPoints[BaseSubobject(RD, Offset)] = AddressPoint;
// Now also add the address point for all our primary bases.
while (1) {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
RD = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// FIXME: Double check this.
if (RD == 0)
break;
if (PrimaryBaseWasVirtual &&
BLayout.getVBaseClassOffset(RD) != Offset)
break;
D1(printf("XXX address point for %s in %s layout %s at offset %d is %d\n",
RD->getNameAsCString(), Class->getNameAsCString(),
LayoutClass->getNameAsCString(), (int)Offset, (int)AddressPoint));
subAddressPoints[std::make_pair(RD, Offset)] = AddressPoint;
AddressPoints[BaseSubobject(RD, Offset)] = AddressPoint;
}
}
void FinishGenerateVtable(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase,
bool PrimaryBaseWasVirtual,
bool MorallyVirtual, int64_t Offset,
bool ForVirtualBase, int64_t CurrentVBaseOffset,
Path_t *Path) {
bool alloc = false;
if (Path == 0) {
alloc = true;
Path = new Path_t;
}
StartNewTable();
extra = 0;
bool DeferVCalls = MorallyVirtual || ForVirtualBase;
int VCallInsertionPoint = VtableComponents.size();
if (!DeferVCalls) {
insertVCalls(VCallInsertionPoint);
} else
// FIXME: just for extra, or for all uses of VCalls.size post this?
extra = -VCalls.size();
// Add the offset to top.
VtableComponents.push_back(BuildVtable ? wrap(-((Offset-LayoutOffset)/8)) : 0);
// Add the RTTI information.
VtableComponents.push_back(rtti);
Index_t AddressPoint = VtableComponents.size();
AppendMethodsToVtable();
// and then the non-virtual bases.
NonVirtualBases(RD, Layout, PrimaryBase, PrimaryBaseWasVirtual,
MorallyVirtual, Offset, CurrentVBaseOffset, Path);
if (ForVirtualBase) {
// FIXME: We're adding to VCalls in callers, we need to do the overrides
// in the inner part, so that we know the complete set of vcalls during
// the build and don't have to insert into methods. Saving out the
// AddressPoint here, would need to be fixed, if we didn't do that. Also
// retroactively adding vcalls for overrides later wind up in the wrong
// place, the vcall slot has to be alloted during the walk of the base
// when the function is first introduces.
AddressPoint += VCalls.size();
insertVCalls(VCallInsertionPoint);
}
AddAddressPoints(RD, Offset, AddressPoint);
if (alloc) {
delete Path;
}
}
void Primaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
int64_t CurrentVBaseOffset) {
if (!RD->isDynamicClass())
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// vtables are composed from the chain of primaries.
if (PrimaryBase && !PrimaryBaseWasVirtual) {
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
Primaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, CurrentVBaseOffset);
}
D1(printf(" doing vcall entries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
// And add the virtuals for the class to the primary vtable.
AddMethods(RD, MorallyVirtual, Offset, CurrentVBaseOffset);
}
void VBPrimaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
bool RDisVirtualBase, int64_t CurrentVBaseOffset,
bool bottom) {
if (!RD->isDynamicClass())
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// vtables are composed from the chain of primaries.
if (PrimaryBase) {
int BaseCurrentVBaseOffset = CurrentVBaseOffset;
if (PrimaryBaseWasVirtual) {
IndirectPrimary.insert(PrimaryBase);
BaseCurrentVBaseOffset = BLayout.getVBaseClassOffset(PrimaryBase);
}
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
VBPrimaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual,
BaseCurrentVBaseOffset, false);
}
D1(printf(" doing vbase entries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
GenerateVBaseOffsets(RD, Offset, updateVBIndex, current_vbindex);
if (RDisVirtualBase || bottom) {
Primaries(RD, MorallyVirtual, Offset, updateVBIndex, current_vbindex,
CurrentVBaseOffset);
}
}
void GenerateVtableForBase(const CXXRecordDecl *RD, int64_t Offset = 0,
bool MorallyVirtual = false,
bool ForVirtualBase = false,
int CurrentVBaseOffset = 0,
Path_t *Path = 0) {
if (!RD->isDynamicClass())
return;
// Construction vtable don't need parts that have no virtual bases and
// aren't morally virtual.
if ((LayoutClass != MostDerivedClass) &&
RD->getNumVBases() == 0 && !MorallyVirtual)
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
extra = 0;
D1(printf("building entries for base %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
if (ForVirtualBase)
extra = VCalls.size();
VBPrimaries(RD, MorallyVirtual, Offset, !ForVirtualBase, 0, ForVirtualBase,
CurrentVBaseOffset, true);
if (Path)
OverrideMethods(Path, MorallyVirtual, Offset, CurrentVBaseOffset);
FinishGenerateVtable(RD, Layout, PrimaryBase, PrimaryBaseWasVirtual,
MorallyVirtual, Offset, ForVirtualBase,
CurrentVBaseOffset, Path);
}
void GenerateVtableForVBases(const CXXRecordDecl *RD,
int64_t Offset = 0,
Path_t *Path = 0) {
bool alloc = false;
if (Path == 0) {
alloc = true;
Path = new Path_t;
}
// FIXME: We also need to override using all paths to a virtual base,
// right now, we just process the first path
Path->push_back(std::make_pair(RD, Offset));
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() && !IndirectPrimary.count(Base)) {
// Mark it so we don't output it twice.
IndirectPrimary.insert(Base);
StartNewTable();
VCall.clear();
int64_t BaseOffset = BLayout.getVBaseClassOffset(Base);
int64_t CurrentVBaseOffset = BaseOffset;
D1(printf("vtable %s virtual base %s\n",
Class->getNameAsCString(), Base->getNameAsCString()));
GenerateVtableForBase(Base, BaseOffset, true, true, CurrentVBaseOffset,
Path);
}
int64_t BaseOffset;
if (i->isVirtual())
BaseOffset = BLayout.getVBaseClassOffset(Base);
else {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
}
if (Base->getNumVBases()) {
GenerateVtableForVBases(Base, BaseOffset, Path);
}
}
Path->pop_back();
if (alloc)
delete Path;
}
};
} // end anonymous namespace
/// TypeConversionRequiresAdjustment - Returns whether conversion from a
/// derived type to a base type requires adjustment.
static bool
TypeConversionRequiresAdjustment(ASTContext &Ctx,
const CXXRecordDecl *DerivedDecl,
const CXXRecordDecl *BaseDecl) {
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/true);
if (!const_cast<CXXRecordDecl *>(DerivedDecl)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseDecl), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return false;
}
// If we found a virtual base we always want to require adjustment.
if (Paths.getDetectedVirtual())
return true;
const CXXBasePath &Path = Paths.front();
for (size_t Start = 0, End = Path.size(); Start != End; ++Start) {
const CXXBasePathElement &Element = Path[Start];
// Check the base class offset.
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Element.Class);
const RecordType *BaseType = Element.Base->getType()->getAs<RecordType>();
const CXXRecordDecl *Base = cast<CXXRecordDecl>(BaseType->getDecl());
if (Layout.getBaseClassOffset(Base) != 0) {
// This requires an adjustment.
return true;
}
}
return false;
}
static bool
TypeConversionRequiresAdjustment(ASTContext &Ctx,
QualType DerivedType, QualType BaseType) {
// Canonicalize the types.
QualType CanDerivedType = Ctx.getCanonicalType(DerivedType);
QualType CanBaseType = Ctx.getCanonicalType(BaseType);
assert(CanDerivedType->getTypeClass() == CanBaseType->getTypeClass() &&
"Types must have same type class!");
if (CanDerivedType == CanBaseType) {
// No adjustment needed.
return false;
}
if (const ReferenceType *RT = dyn_cast<ReferenceType>(CanDerivedType)) {
CanDerivedType = RT->getPointeeType();
CanBaseType = cast<ReferenceType>(CanBaseType)->getPointeeType();
} else if (const PointerType *PT = dyn_cast<PointerType>(CanDerivedType)) {
CanDerivedType = PT->getPointeeType();
CanBaseType = cast<PointerType>(CanBaseType)->getPointeeType();
} else {
assert(false && "Unexpected return type!");
}
if (CanDerivedType == CanBaseType) {
// No adjustment needed.
return false;
}
const CXXRecordDecl *DerivedDecl =
cast<CXXRecordDecl>(cast<RecordType>(CanDerivedType)->getDecl());
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(cast<RecordType>(CanBaseType)->getDecl());
return TypeConversionRequiresAdjustment(Ctx, DerivedDecl, BaseDecl);
}
bool VtableBuilder::OverrideMethod(GlobalDecl GD, bool MorallyVirtual,
Index_t OverrideOffset, Index_t Offset,
int64_t CurrentVBaseOffset) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const bool isPure = MD->isPure();
// FIXME: Should OverrideOffset's be Offset?
for (CXXMethodDecl::method_iterator mi = MD->begin_overridden_methods(),
e = MD->end_overridden_methods(); mi != e; ++mi) {
GlobalDecl OGD;
const CXXMethodDecl *OMD = *mi;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(OMD))
OGD = GlobalDecl(DD, GD.getDtorType());
else
OGD = OMD;
// Check whether this is the method being overridden in this section of
// the vtable.
uint64_t Index;
if (!Methods.getIndex(OGD, Index))
continue;
// Get the original method, which we should be computing thunks, etc,
// against.
OGD = Methods.getOrigMethod(Index);
OMD = cast<CXXMethodDecl>(OGD.getDecl());
QualType ReturnType =
MD->getType()->getAs<FunctionType>()->getResultType();
QualType OverriddenReturnType =
OMD->getType()->getAs<FunctionType>()->getResultType();
// Check if we need a return type adjustment.
if (TypeConversionRequiresAdjustment(CGM.getContext(), ReturnType,
OverriddenReturnType)) {
CanQualType &BaseReturnType = BaseReturnTypes[Index];
// Insert the base return type.
if (BaseReturnType.isNull())
BaseReturnType =
CGM.getContext().getCanonicalType(OverriddenReturnType);
}
Methods.OverrideMethod(OGD, GD);
ThisAdjustments.erase(Index);
if (MorallyVirtual || VCall.count(OGD)) {
Index_t &idx = VCall[OGD];
if (idx == 0) {
NonVirtualOffset[GD] = -OverrideOffset/8 + CurrentVBaseOffset/8;
VCallOffset[GD] = OverrideOffset/8;
idx = VCalls.size()+1;
VCalls.push_back(0);
D1(printf(" vcall for %s at %d with delta %d most derived %s\n",
MD->getNameAsString().c_str(), (int)-idx-3,
(int)VCalls[idx-1], Class->getNameAsCString()));
} else {
NonVirtualOffset[GD] = NonVirtualOffset[OGD];
VCallOffset[GD] = VCallOffset[OGD];
VCalls[idx-1] = -VCallOffset[OGD] + OverrideOffset/8;
D1(printf(" vcall patch for %s at %d with delta %d most derived %s\n",
MD->getNameAsString().c_str(), (int)-idx-3,
(int)VCalls[idx-1], Class->getNameAsCString()));
}
int64_t NonVirtualAdjustment = NonVirtualOffset[GD];
int64_t VirtualAdjustment =
-((idx + extra + 2) * LLVMPointerWidth / 8);
// Optimize out virtual adjustments of 0.
if (VCalls[idx-1] == 0)
VirtualAdjustment = 0;
ThunkAdjustment ThisAdjustment(NonVirtualAdjustment,
VirtualAdjustment);
if (!isPure && !ThisAdjustment.isEmpty()) {
ThisAdjustments[Index] = ThisAdjustment;
SavedAdjustments.push_back(
std::make_pair(GD, std::make_pair(OGD, ThisAdjustment)));
}
VCall[GD] = idx;
return true;
}
int64_t NonVirtualAdjustment = -VCallOffset[OGD] + OverrideOffset/8;
if (NonVirtualAdjustment) {
ThunkAdjustment ThisAdjustment(NonVirtualAdjustment, 0);
if (!isPure) {
ThisAdjustments[Index] = ThisAdjustment;
SavedAdjustments.push_back(
std::make_pair(GD, std::make_pair(OGD, ThisAdjustment)));
}
}
return true;
}
return false;
}
void VtableBuilder::AppendMethodsToVtable() {
if (!BuildVtable) {
VtableComponents.insert(VtableComponents.end(), Methods.size(),
(llvm::Constant *)0);
ThisAdjustments.clear();
BaseReturnTypes.clear();
Methods.clear();
return;
}
// Reserve room in the vtable for our new methods.
VtableComponents.reserve(VtableComponents.size() + Methods.size());
for (unsigned i = 0, e = Methods.size(); i != e; ++i) {
GlobalDecl GD = Methods[i];
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
// Get the 'this' pointer adjustment.
ThunkAdjustment ThisAdjustment = ThisAdjustments.lookup(i);
// Construct the return type adjustment.
ThunkAdjustment ReturnAdjustment;
QualType BaseReturnType = BaseReturnTypes.lookup(i);
if (!BaseReturnType.isNull() && !MD->isPure()) {
QualType DerivedType =
MD->getType()->getAs<FunctionType>()->getResultType();
int64_t NonVirtualAdjustment =
getNVOffset(BaseReturnType, DerivedType) / 8;
int64_t VirtualAdjustment =
getVbaseOffset(BaseReturnType, DerivedType);
ReturnAdjustment = ThunkAdjustment(NonVirtualAdjustment,
VirtualAdjustment);
}
llvm::Constant *Method = 0;
if (!ReturnAdjustment.isEmpty()) {
// Build a covariant thunk.
CovariantThunkAdjustment Adjustment(ThisAdjustment, ReturnAdjustment);
Method = wrap(CGM.GetAddrOfCovariantThunk(GD, Adjustment));
} else if (!ThisAdjustment.isEmpty()) {
// Build a "regular" thunk.
Method = wrap(CGM.GetAddrOfThunk(GD, ThisAdjustment));
} else if (MD->isPure()) {
// We have a pure virtual method.
Method = getPureVirtualFn();
} else {
// We have a good old regular method.
Method = WrapAddrOf(GD);
}
// Add the method to the vtable.
VtableComponents.push_back(Method);
}
ThisAdjustments.clear();
BaseReturnTypes.clear();
Methods.clear();
}
void CGVtableInfo::ComputeMethodVtableIndices(const CXXRecordDecl *RD) {
// Itanium C++ ABI 2.5.2:
// The order of the virtual function pointers in a virtual table is the
// order of declaration of the corresponding member functions in the class.
//
// There is an entry for any virtual function declared in a class,
// whether it is a new function or overrides a base class function,
// unless it overrides a function from the primary base, and conversion
// between their return types does not require an adjustment.
int64_t CurrentIndex = 0;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
if (PrimaryBase) {
assert(PrimaryBase->isDefinition() &&
"Should have the definition decl of the primary base!");
// Since the record decl shares its vtable pointer with the primary base
// we need to start counting at the end of the primary base's vtable.
CurrentIndex = getNumVirtualFunctionPointers(PrimaryBase);
}
// Collect all the primary bases, so we can check whether methods override
// a method from the base.
llvm::SmallPtrSet<const CXXRecordDecl *, 5> PrimaryBases;
for (ASTRecordLayout::primary_base_info_iterator
I = Layout.primary_base_begin(), E = Layout.primary_base_end();
I != E; ++I)
PrimaryBases.insert((*I).getBase());
const CXXDestructorDecl *ImplicitVirtualDtor = 0;
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end(); i != e; ++i) {
const CXXMethodDecl *MD = *i;
// We only want virtual methods.
if (!MD->isVirtual())
continue;
bool ShouldAddEntryForMethod = true;
// Check if this method overrides a method in the primary base.
for (CXXMethodDecl::method_iterator i = MD->begin_overridden_methods(),
e = MD->end_overridden_methods(); i != e; ++i) {
const CXXMethodDecl *OverriddenMD = *i;
const CXXRecordDecl *OverriddenRD = OverriddenMD->getParent();
assert(OverriddenMD->isCanonicalDecl() &&
"Should have the canonical decl of the overridden RD!");
if (PrimaryBases.count(OverriddenRD)) {
// Check if converting from the return type of the method to the
// return type of the overridden method requires conversion.
QualType ReturnType =
MD->getType()->getAs<FunctionType>()->getResultType();
QualType OverriddenReturnType =
OverriddenMD->getType()->getAs<FunctionType>()->getResultType();
if (!TypeConversionRequiresAdjustment(CGM.getContext(),
ReturnType, OverriddenReturnType)) {
// This index is shared between the index in the vtable of the primary
// base class.
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
const CXXDestructorDecl *OverriddenDD =
cast<CXXDestructorDecl>(OverriddenMD);
// Add both the complete and deleting entries.
MethodVtableIndices[GlobalDecl(DD, Dtor_Complete)] =
getMethodVtableIndex(GlobalDecl(OverriddenDD, Dtor_Complete));
MethodVtableIndices[GlobalDecl(DD, Dtor_Deleting)] =
getMethodVtableIndex(GlobalDecl(OverriddenDD, Dtor_Deleting));
} else {
MethodVtableIndices[MD] = getMethodVtableIndex(OverriddenMD);
}
// We don't need to add an entry for this method.
ShouldAddEntryForMethod = false;
break;
}
}
}
if (!ShouldAddEntryForMethod)
continue;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
if (MD->isImplicit()) {
assert(!ImplicitVirtualDtor &&
"Did already see an implicit virtual dtor!");
ImplicitVirtualDtor = DD;
continue;
}
// Add the complete dtor.
MethodVtableIndices[GlobalDecl(DD, Dtor_Complete)] = CurrentIndex++;
// Add the deleting dtor.
MethodVtableIndices[GlobalDecl(DD, Dtor_Deleting)] = CurrentIndex++;
} else {
// Add the entry.
MethodVtableIndices[MD] = CurrentIndex++;
}
}
if (ImplicitVirtualDtor) {
// Itanium C++ ABI 2.5.2:
// If a class has an implicitly-defined virtual destructor,
// its entries come after the declared virtual function pointers.
// Add the complete dtor.
MethodVtableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Complete)] =
CurrentIndex++;
// Add the deleting dtor.
MethodVtableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Deleting)] =
CurrentIndex++;
}
NumVirtualFunctionPointers[RD] = CurrentIndex;
}
uint64_t CGVtableInfo::getNumVirtualFunctionPointers(const CXXRecordDecl *RD) {
llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
NumVirtualFunctionPointers.find(RD);
if (I != NumVirtualFunctionPointers.end())
return I->second;
ComputeMethodVtableIndices(RD);
I = NumVirtualFunctionPointers.find(RD);
assert(I != NumVirtualFunctionPointers.end() && "Did not find entry!");
return I->second;
}
uint64_t CGVtableInfo::getMethodVtableIndex(GlobalDecl GD) {
MethodVtableIndicesTy::iterator I = MethodVtableIndices.find(GD);
if (I != MethodVtableIndices.end())
return I->second;
const CXXRecordDecl *RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
ComputeMethodVtableIndices(RD);
I = MethodVtableIndices.find(GD);
assert(I != MethodVtableIndices.end() && "Did not find index!");
return I->second;
}
CGVtableInfo::AdjustmentVectorTy*
CGVtableInfo::getAdjustments(GlobalDecl GD) {
SavedAdjustmentsTy::iterator I = SavedAdjustments.find(GD);
if (I != SavedAdjustments.end())
return &I->second;
const CXXRecordDecl *RD = cast<CXXRecordDecl>(GD.getDecl()->getDeclContext());
if (!SavedAdjustmentRecords.insert(RD).second)
return 0;
AddressPointsMapTy AddressPoints;
VtableBuilder b(RD, RD, 0, CGM, false, AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
b.GenerateVtableForBase(RD);
b.GenerateVtableForVBases(RD);
for (VtableBuilder::SavedAdjustmentsVectorTy::iterator
i = b.getSavedAdjustments().begin(),
e = b.getSavedAdjustments().end(); i != e; i++)
SavedAdjustments[i->first].push_back(i->second);
I = SavedAdjustments.find(GD);
if (I != SavedAdjustments.end())
return &I->second;
return 0;
}
int64_t CGVtableInfo::getVirtualBaseOffsetIndex(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase) {
ClassPairTy ClassPair(RD, VBase);
VirtualBaseClassIndiciesTy::iterator I =
VirtualBaseClassIndicies.find(ClassPair);
if (I != VirtualBaseClassIndicies.end())
return I->second;
// FIXME: This seems expensive. Can we do a partial job to get
// just this data.
AddressPointsMapTy AddressPoints;
VtableBuilder b(RD, RD, 0, CGM, false, AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
b.GenerateVtableForBase(RD);
b.GenerateVtableForVBases(RD);
for (llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
b.getVBIndex().begin(), E = b.getVBIndex().end(); I != E; ++I) {
// Insert all types.
ClassPairTy ClassPair(RD, I->first);
VirtualBaseClassIndicies.insert(std::make_pair(ClassPair, I->second));
}
I = VirtualBaseClassIndicies.find(ClassPair);
assert(I != VirtualBaseClassIndicies.end() && "Did not find index!");
return I->second;
}
uint64_t CGVtableInfo::getVtableAddressPoint(const CXXRecordDecl *RD) {
uint64_t AddressPoint =
(*(*(CGM.getVtableInfo().AddressPoints[RD]))[RD])[std::make_pair(RD, 0)];
return AddressPoint;
}
llvm::GlobalVariable *
CGVtableInfo::GenerateVtable(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition,
const CXXRecordDecl *LayoutClass,
const CXXRecordDecl *RD, uint64_t Offset,
AddressPointsMapTy& AddressPoints) {
llvm::SmallString<256> OutName;
if (LayoutClass != RD)
CGM.getMangleContext().mangleCXXCtorVtable(LayoutClass, Offset / 8,
RD, OutName);
else
CGM.getMangleContext().mangleCXXVtable(RD, OutName);
llvm::StringRef Name = OutName.str();
llvm::GlobalVariable *GV = CGM.getModule().getGlobalVariable(Name);
if (GV == 0 || CGM.getVtableInfo().AddressPoints[LayoutClass] == 0 ||
GV->isDeclaration()) {
VtableBuilder b(RD, LayoutClass, Offset, CGM, GenerateDefinition,
AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
// First comes the vtables for all the non-virtual bases...
b.GenerateVtableForBase(RD, Offset);
// then the vtables for all the virtual bases.
b.GenerateVtableForVBases(RD, Offset);
llvm::Constant *Init = 0;
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
llvm::ArrayType *ArrayType =
llvm::ArrayType::get(Int8PtrTy, b.getVtableComponents().size());
if (GenerateDefinition)
Init = llvm::ConstantArray::get(ArrayType, &b.getVtableComponents()[0],
b.getVtableComponents().size());
llvm::GlobalVariable *OGV = GV;
GV = new llvm::GlobalVariable(CGM.getModule(), ArrayType,
/*isConstant=*/true, Linkage, Init, Name);
CGM.setGlobalVisibility(GV, RD);
if (OGV) {
GV->takeName(OGV);
llvm::Constant *NewPtr =
llvm::ConstantExpr::getBitCast(GV, OGV->getType());
OGV->replaceAllUsesWith(NewPtr);
OGV->eraseFromParent();
}
}
return GV;
}
namespace {
class VTTBuilder {
/// Inits - The list of values built for the VTT.
std::vector<llvm::Constant *> &Inits;
/// Class - The most derived class that this vtable is being built for.
const CXXRecordDecl *Class;
CodeGenModule &CGM; // Per-module state.
llvm::SmallSet<const CXXRecordDecl *, 32> SeenVBase;
/// BLayout - Layout for the most derived class that this vtable is being
/// built for.
const ASTRecordLayout &BLayout;
CGVtableInfo::AddrMap_t &AddressPoints;
// vtbl - A pointer to the vtable for Class.
llvm::Constant *ClassVtbl;
llvm::LLVMContext &VMContext;
/// SeenVBasesInSecondary - The seen virtual bases when building the
/// secondary virtual pointers.
llvm::SmallPtrSet<const CXXRecordDecl *, 32> SeenVBasesInSecondary;
llvm::DenseMap<const CXXRecordDecl *, uint64_t> SubVTTIndicies;
bool GenerateDefinition;
llvm::DenseMap<BaseSubobject, llvm::Constant *> CtorVtables;
llvm::DenseMap<std::pair<const CXXRecordDecl *, BaseSubobject>, uint64_t>
CtorVtableAddressPoints;
llvm::Constant *getCtorVtable(const BaseSubobject &Base) {
if (!GenerateDefinition)
return 0;
llvm::Constant *&CtorVtable = CtorVtables[Base];
if (!CtorVtable) {
// Build the vtable.
CGVtableInfo::CtorVtableInfo Info
= CGM.getVtableInfo().getCtorVtable(Class, Base);
CtorVtable = Info.Vtable;
// Add the address points for this base.
for (CGVtableInfo::AddressPointsMapTy::const_iterator I =
Info.AddressPoints.begin(), E = Info.AddressPoints.end();
I != E; ++I) {
uint64_t &AddressPoint =
CtorVtableAddressPoints[std::make_pair(Base.getBase(), I->first)];
// Check if we already have the address points for this base.
if (AddressPoint)
break;
// Otherwise, insert it.
AddressPoint = I->second;
}
}
return CtorVtable;
}
/// BuildVtablePtr - Build up a referene to the given secondary vtable
llvm::Constant *BuildVtablePtr(llvm::Constant *Vtable,
const CXXRecordDecl *VtableClass,
const CXXRecordDecl *RD,
uint64_t Offset) {
if (!GenerateDefinition)
return 0;
uint64_t AddressPoint;
if (VtableClass != Class) {
// We have a ctor vtable, look for the address point in the ctor vtable
// address points.
AddressPoint =
CtorVtableAddressPoints[std::make_pair(VtableClass,
BaseSubobject(RD, Offset))];
} else {
AddressPoint =
(*AddressPoints[VtableClass])[std::make_pair(RD, Offset)];
}
// FIXME: We can never have 0 address point. Do this for now so gepping
// retains the same structure. Later we'll just assert.
if (AddressPoint == 0)
AddressPoint = 1;
D1(printf("XXX address point for %s in %s layout %s at offset %d was %d\n",
RD->getNameAsCString(), VtblClass->getNameAsCString(),
Class->getNameAsCString(), (int)Offset, (int)AddressPoint));
llvm::Value *Idxs[] = {
llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), 0),
llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), AddressPoint)
};
llvm::Constant *Init =
llvm::ConstantExpr::getInBoundsGetElementPtr(Vtable, Idxs, 2);
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
return llvm::ConstantExpr::getBitCast(Init, Int8PtrTy);
}
/// Secondary - Add the secondary vtable pointers to Inits. Offset is the
/// current offset in bits to the object we're working on.
void Secondary(const CXXRecordDecl *RD, llvm::Constant *vtbl,
const CXXRecordDecl *VtblClass, uint64_t Offset=0,
bool MorallyVirtual=false) {
if (RD->getNumVBases() == 0 && ! MorallyVirtual)
return;
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());
// We only want to visit each virtual base once.
if (i->isVirtual() && SeenVBasesInSecondary.count(Base))
continue;
// 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 (!Base->isDynamicClass())
continue;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
bool NonVirtualPrimaryBase;
NonVirtualPrimaryBase = !PrimaryBaseWasVirtual && Base == PrimaryBase;
bool BaseMorallyVirtual = MorallyVirtual | i->isVirtual();
uint64_t BaseOffset;
if (!i->isVirtual()) {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
} else
BaseOffset = BLayout.getVBaseClassOffset(Base);
llvm::Constant *subvtbl = vtbl;
const CXXRecordDecl *subVtblClass = VtblClass;
if ((Base->getNumVBases() || BaseMorallyVirtual)
&& !NonVirtualPrimaryBase) {
llvm::Constant *init;
if (BaseMorallyVirtual || VtblClass == Class)
init = BuildVtablePtr(vtbl, VtblClass, Base, BaseOffset);
else {
init = getCtorVtable(BaseSubobject(Base, BaseOffset));
subvtbl = init;
subVtblClass = Base;
init = BuildVtablePtr(init, Class, Base, BaseOffset);
}
Inits.push_back(init);
}
if (i->isVirtual())
SeenVBasesInSecondary.insert(Base);
Secondary(Base, subvtbl, subVtblClass, BaseOffset, BaseMorallyVirtual);
}
}
/// BuiltVTT - Add the VTT to Inits. Offset is the offset in bits to the
/// currnet object we're working on.
void BuildVTT(const CXXRecordDecl *RD, uint64_t Offset, bool MorallyVirtual) {
// Itanium C++ ABI 2.6.2:
// An array of virtual table addresses, called the VTT, is declared for
// each class type that has indirect or direct virtual base classes.
if (RD->getNumVBases() == 0)
return;
// Remember the sub-VTT index.
SubVTTIndicies[RD] = Inits.size();
llvm::Constant *Vtable;
const CXXRecordDecl *VtableClass;
// First comes the primary virtual table pointer...
if (MorallyVirtual) {
Vtable = ClassVtbl;
VtableClass = Class;
} else {
Vtable = getCtorVtable(BaseSubobject(RD, Offset));
VtableClass = RD;
}
llvm::Constant *Init = BuildVtablePtr(Vtable, VtableClass, RD, Offset);
Inits.push_back(Init);
// then the secondary VTTs....
SecondaryVTTs(RD, Offset, MorallyVirtual);
// Make sure to clear the set of seen virtual bases.
SeenVBasesInSecondary.clear();
// and last the secondary vtable pointers.
Secondary(RD, Vtable, VtableClass, Offset, MorallyVirtual);
}
/// SecondaryVTTs - Add the secondary VTTs to Inits. The secondary VTTs are
/// built from each direct non-virtual proper base that requires a VTT in
/// declaration order.
void SecondaryVTTs(const CXXRecordDecl *RD, uint64_t Offset=0,
bool MorallyVirtual=false) {
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())
continue;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
uint64_t BaseOffset = Offset + Layout.getBaseClassOffset(Base);
BuildVTT(Base, BaseOffset, MorallyVirtual);
}
}
/// VirtualVTTs - Add the VTT for each proper virtual base in inheritance
/// graph preorder.
void VirtualVTTs(const CXXRecordDecl *RD) {
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() && !SeenVBase.count(Base)) {
SeenVBase.insert(Base);
uint64_t BaseOffset = BLayout.getVBaseClassOffset(Base);
BuildVTT(Base, BaseOffset, false);
}
VirtualVTTs(Base);
}
}
public:
VTTBuilder(std::vector<llvm::Constant *> &inits, const CXXRecordDecl *c,
CodeGenModule &cgm, bool GenerateDefinition)
: Inits(inits), Class(c), CGM(cgm),
BLayout(cgm.getContext().getASTRecordLayout(c)),
AddressPoints(*cgm.getVtableInfo().AddressPoints[c]),
VMContext(cgm.getModule().getContext()),
GenerateDefinition(GenerateDefinition) {
// First comes the primary virtual table pointer for the complete class...
ClassVtbl = GenerateDefinition ? CGM.getVtableInfo().getVtable(Class) : 0;
llvm::Constant *Init = BuildVtablePtr(ClassVtbl, Class, Class, 0);
Inits.push_back(Init);
// then the secondary VTTs...
SecondaryVTTs(Class);
// Make sure to clear the set of seen virtual bases.
SeenVBasesInSecondary.clear();
// then the secondary vtable pointers...
Secondary(Class, ClassVtbl, Class);
// and last, the virtual VTTs.
VirtualVTTs(Class);
}
llvm::DenseMap<const CXXRecordDecl *, uint64_t> &getSubVTTIndicies() {
return SubVTTIndicies;
}
};
}
llvm::GlobalVariable *
CGVtableInfo::GenerateVTT(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition,
const CXXRecordDecl *RD) {
// Only classes that have virtual bases need a VTT.
if (RD->getNumVBases() == 0)
return 0;
llvm::SmallString<256> OutName;
CGM.getMangleContext().mangleCXXVTT(RD, OutName);
llvm::StringRef Name = OutName.str();
D1(printf("vtt %s\n", RD->getNameAsCString()));
llvm::GlobalVariable *GV = CGM.getModule().getGlobalVariable(Name);
if (GV == 0 || GV->isDeclaration()) {
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
std::vector<llvm::Constant *> inits;
VTTBuilder b(inits, RD, CGM, GenerateDefinition);
const llvm::ArrayType *Type = llvm::ArrayType::get(Int8PtrTy, inits.size());
llvm::Constant *Init = 0;
if (GenerateDefinition)
Init = llvm::ConstantArray::get(Type, inits);
llvm::GlobalVariable *OldGV = GV;
GV = new llvm::GlobalVariable(CGM.getModule(), Type, /*isConstant=*/true,
Linkage, Init, Name);
CGM.setGlobalVisibility(GV, RD);
if (OldGV) {
GV->takeName(OldGV);
llvm::Constant *NewPtr =
llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
OldGV->replaceAllUsesWith(NewPtr);
OldGV->eraseFromParent();
}
}
return GV;
}
void CGVtableInfo::GenerateClassData(llvm::GlobalVariable::LinkageTypes Linkage,
const CXXRecordDecl *RD) {
llvm::GlobalVariable *&Vtable = Vtables[RD];
if (Vtable) {
assert(Vtable->getInitializer() && "Vtable doesn't have a definition!");
return;
}
AddressPointsMapTy AddressPoints;
Vtable = GenerateVtable(Linkage, /*GenerateDefinition=*/true, RD, RD, 0,
AddressPoints);
GenerateVTT(Linkage, /*GenerateDefinition=*/true, RD);
}
llvm::GlobalVariable *CGVtableInfo::getVtable(const CXXRecordDecl *RD) {
llvm::GlobalVariable *Vtable = Vtables.lookup(RD);
if (!Vtable) {
AddressPointsMapTy AddressPoints;
Vtable = GenerateVtable(llvm::GlobalValue::ExternalLinkage,
/*GenerateDefinition=*/false, RD, RD, 0,
AddressPoints);
}
return Vtable;
}
CGVtableInfo::CtorVtableInfo
CGVtableInfo::getCtorVtable(const CXXRecordDecl *RD,
const BaseSubobject &Base) {
CtorVtableInfo Info;
Info.Vtable = GenerateVtable(llvm::GlobalValue::InternalLinkage,
/*GenerateDefinition=*/true,
RD, Base.getBase(), Base.getBaseOffset(),
Info.AddressPoints);
return Info;
}
llvm::GlobalVariable *CGVtableInfo::getVTT(const CXXRecordDecl *RD) {
return GenerateVTT(llvm::GlobalValue::ExternalLinkage,
/*GenerateDefinition=*/false, RD);
}
void CGVtableInfo::MaybeEmitVtable(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const CXXRecordDecl *RD = MD->getParent();
// If the class doesn't have a vtable we don't need to emit one.
if (!RD->isDynamicClass())
return;
// Get the key function.
const CXXMethodDecl *KeyFunction = CGM.getContext().getKeyFunction(RD);
if (KeyFunction) {
// We don't have the right key function.
if (KeyFunction->getCanonicalDecl() != MD->getCanonicalDecl())
return;
}
// Emit the data.
GenerateClassData(CGM.getVtableLinkage(RD), RD);
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end(); i != e; ++i) {
if ((*i)->isVirtual() && ((*i)->hasInlineBody() || (*i)->isImplicit())) {
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(*i)) {
CGM.BuildThunksForVirtual(GlobalDecl(DD, Dtor_Complete));
CGM.BuildThunksForVirtual(GlobalDecl(DD, Dtor_Deleting));
} else {
CGM.BuildThunksForVirtual(GlobalDecl(*i));
}
}
}
}
bool CGVtableInfo::needsVTTParameter(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
// We don't have any virtual bases, just return early.
if (!MD->getParent()->getNumVBases())
return false;
// Check if we have a base constructor.
if (isa<CXXConstructorDecl>(MD) && GD.getCtorType() == Ctor_Base)
return true;
// Check if we have a base destructor.
if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
return true;
return false;
}
uint64_t CGVtableInfo::getSubVTTIndex(const CXXRecordDecl *RD,
const CXXRecordDecl *Base) {
ClassPairTy ClassPair(RD, Base);
SubVTTIndiciesTy::iterator I =
SubVTTIndicies.find(ClassPair);
if (I != SubVTTIndicies.end())
return I->second;
std::vector<llvm::Constant *> inits;
VTTBuilder Builder(inits, RD, CGM, /*GenerateDefinition=*/false);
for (llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
Builder.getSubVTTIndicies().begin(),
E = Builder.getSubVTTIndicies().end(); I != E; ++I) {
// Insert all indices.
ClassPairTy ClassPair(RD, I->first);
SubVTTIndicies.insert(std::make_pair(ClassPair, I->second));
}
I = SubVTTIndicies.find(ClassPair);
assert(I != SubVTTIndicies.end() && "Did not find index!");
return I->second;
}