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Add vtable caching to prevent multiple vtables for the same class from 

being generated.

Add the most derived vtable pointer to the VTT.

llvm-svn: 86671
This commit is contained in:
Mike Stump 2009-11-10 07:44:33 +00:00
parent 1559bedcc7
commit d846d0825b
5 changed files with 41 additions and 24 deletions
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2
clang/lib/CodeGen/CGCXX.cpp
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@ -1492,7 +1492,7 @@ void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
PtrPtr8Ty = llvm::PointerType::get(Ptr8Ty, 0);
VtableField = Builder.CreateBitCast(LoadOfThis, PtrPtr8Ty);
llvm::Value *vtable = GenerateVtable(ClassDecl);
llvm::Value *vtable = CGM.getVtableInfo().getVtable(ClassDecl);
Builder.CreateStore(vtable, VtableField);
}
}

47
clang/lib/CodeGen/CGVtable.cpp
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@ -681,10 +681,10 @@ int64_t CGVtableInfo::getVirtualBaseOffsetIndex(const CXXRecordDecl *RD,
return I->second;
}
llvm::Value *CodeGenFunction::GenerateVtable(const CXXRecordDecl *RD) {
llvm::Constant *CodeGenModule::GenerateVtable(const CXXRecordDecl *RD) {
llvm::SmallString<256> OutName;
llvm::raw_svector_ostream Out(OutName);
mangleCXXVtable(CGM.getMangleContext(), RD, Out);
mangleCXXVtable(getMangleContext(), RD, Out);
llvm::GlobalVariable::LinkageTypes linktype;
linktype = llvm::GlobalValue::LinkOnceODRLinkage;
@ -692,7 +692,7 @@ llvm::Value *CodeGenFunction::GenerateVtable(const CXXRecordDecl *RD) {
llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
int64_t AddressPoint;
VtableBuilder b(methods, RD, CGM);
VtableBuilder b(methods, RD, *this);
D1(printf("vtable %s\n", RD->getNameAsCString()));
// First comes the vtables for all the non-virtual bases...
@ -701,17 +701,19 @@ llvm::Value *CodeGenFunction::GenerateVtable(const CXXRecordDecl *RD) {
// then the vtables for all the virtual bases.
b.GenerateVtableForVBases(RD);
//GenerateVTT(RD);
llvm::Constant *C;
llvm::ArrayType *type = llvm::ArrayType::get(Ptr8Ty, methods.size());
C = llvm::ConstantArray::get(type, methods);
llvm::Value *vtable = new llvm::GlobalVariable(CGM.getModule(), type, true,
linktype, C, Out.str());
vtable = Builder.CreateBitCast(vtable, Ptr8Ty);
vtable = Builder.CreateGEP(vtable,
llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext),
AddressPoint*LLVMPointerWidth/8));
llvm::Constant *vtable = new llvm::GlobalVariable(getModule(), type,
true, linktype, C,
Out.str());
vtable = llvm::ConstantExpr::getBitCast(vtable, Ptr8Ty);
llvm::Constant *AddressPointC;
uint32_t LLVMPointerWidth = getContext().Target.getPointerWidth(0);
AddressPointC = llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext),
AddressPoint*LLVMPointerWidth/8);
vtable = llvm::ConstantExpr::getGetElementPtr(vtable, &AddressPointC, 1);
return vtable;
}
@ -725,28 +727,39 @@ class VTTBuilder {
public:
VTTBuilder(std::vector<llvm::Constant *> &inits, const CXXRecordDecl *c,
CodeGenModule &cgm) : Inits(inits), Class(c), CGM(cgm) {
Inits.push_back(CGM.getVtableInfo().getVtable(Class));
}
};
llvm::Value *CodeGenFunction::GenerateVTT(const CXXRecordDecl *RD) {
llvm::Constant *CodeGenModule::GenerateVTT(const CXXRecordDecl *RD) {
llvm::SmallString<256> OutName;
llvm::raw_svector_ostream Out(OutName);
mangleCXXVTT(CGM.getMangleContext(), RD, Out);
mangleCXXVTT(getMangleContext(), RD, Out);
llvm::GlobalVariable::LinkageTypes linktype;
linktype = llvm::GlobalValue::LinkOnceODRLinkage;
std::vector<llvm::Constant *> inits;
llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
VTTBuilder b(inits, RD, CGM);
VTTBuilder b(inits, RD, *this);
D1(printf("vtt %s\n", RD->getNameAsCString()));
llvm::Constant *C;
llvm::ArrayType *type = llvm::ArrayType::get(Ptr8Ty, inits.size());
C = llvm::ConstantArray::get(type, inits);
llvm::Value *vtt = new llvm::GlobalVariable(CGM.getModule(), type, true,
linktype, C, Out.str());
vtt = Builder.CreateBitCast(vtt, Ptr8Ty);
llvm::Constant *vtt = new llvm::GlobalVariable(getModule(), type, true,
linktype, C, Out.str());
vtt = llvm::ConstantExpr::getBitCast(vtt, Ptr8Ty);
return vtt;
}
llvm::Constant *CGVtableInfo::getVtable(const CXXRecordDecl *RD) {
llvm::Constant *&vtbl = Vtables[RD];
if (vtbl)
return vtbl;
vtbl = CGM.GenerateVtable(RD);
CGM.GenerateVTT(RD);
return vtbl;
}

4
clang/lib/CodeGen/CGVtable.h
View File

@ -38,6 +38,8 @@ class CGVtableInfo {
/// offsets for virtual bases of a class are stored.
typedef llvm::DenseMap<ClassPairTy, int64_t> VirtualBaseClassIndiciesTy;
VirtualBaseClassIndiciesTy VirtualBaseClassIndicies;
llvm::DenseMap<const CXXRecordDecl *, llvm::Constant *> Vtables;
public:
CGVtableInfo(CodeGenModule &CGM)
: CGM(CGM) { }
@ -54,6 +56,8 @@ public:
/// base.
int64_t getVirtualBaseOffsetIndex(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase);
llvm::Constant *getVtable(const CXXRecordDecl *RD);
};
}

6
clang/lib/CodeGen/CodeGenFunction.h
View File

@ -381,12 +381,6 @@ public:
/// legal to call this function even if there is no current insertion point.
void FinishFunction(SourceLocation EndLoc=SourceLocation());
/// GenerateVtable - Generate the vtable for the given type.
llvm::Value *GenerateVtable(const CXXRecordDecl *RD);
/// GenerateVTT - Generate the VTT for the given type.
llvm::Value *GenerateVTT(const CXXRecordDecl *RD);
/// DynamicTypeAdjust - Do the non-virtual and virtual adjustments on an
/// object pointer to alter the dynamic type of the pointer. Used by
/// GenerateCovariantThunk for building thunks.

6
clang/lib/CodeGen/CodeGenModule.h
View File

@ -252,6 +252,12 @@ public:
llvm::Constant *GetAddrOfFunction(GlobalDecl GD,
const llvm::Type *Ty = 0);
/// GenerateVtable - Generate the vtable for the given type.
llvm::Constant *GenerateVtable(const CXXRecordDecl *RD);
/// GenerateVTT - Generate the VTT for the given type.
llvm::Constant *GenerateVTT(const CXXRecordDecl *RD);
/// GenerateRtti - Generate the rtti information for the given type.
llvm::Constant *GenerateRtti(const CXXRecordDecl *RD);