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Abstract out member-pointer creation. I'm really unhappy about the current 

duplication between the constant and non-constant paths in all of this.

Implement ARM ABI semantics for member pointer constants and conversion.

llvm-svn: 111772
This commit is contained in:
John McCall 2010-08-22 06:43:33 +00:00
parent 84fa510aa9
commit 1c456c89dc
9 changed files with 154 additions and 81 deletions
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49
clang/lib/CodeGen/CGCXX.cpp
View File

@ -287,44 +287,6 @@ CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
return cast<llvm::Function>(GetOrCreateLLVMFunction(Name, FTy, GD));
}
llvm::Constant *
CodeGenModule::GetCXXMemberFunctionPointerValue(const CXXMethodDecl *MD) {
assert(MD->isInstance() && "Member function must not be static!");
MD = MD->getCanonicalDecl();
const llvm::Type *PtrDiffTy = Types.ConvertType(Context.getPointerDiffType());
// Get the function pointer (or index if this is a virtual function).
if (MD->isVirtual()) {
uint64_t Index = VTables.getMethodVTableIndex(MD);
// FIXME: We shouldn't use / 8 here.
uint64_t PointerWidthInBytes = Context.Target.getPointerWidth(0) / 8;
// Itanium C++ ABI 2.3:
// For a non-virtual function, this field is a simple function pointer.
// For a virtual function, it is 1 plus the virtual table offset
// (in bytes) of the function, represented as a ptrdiff_t.
return llvm::ConstantInt::get(PtrDiffTy, (Index * PointerWidthInBytes) + 1);
}
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *Ty;
// Check whether the function has a computable LLVM signature.
if (!CodeGenTypes::VerifyFuncTypeComplete(FPT)) {
// The function has a computable LLVM signature; use the correct type.
Ty = Types.GetFunctionType(Types.getFunctionInfo(MD), FPT->isVariadic());
} else {
// Use an arbitrary non-function type to tell GetAddrOfFunction that the
// function type is incomplete.
Ty = PtrDiffTy;
}
llvm::Constant *FuncPtr = GetAddrOfFunction(MD, Ty);
return llvm::ConstantExpr::getPtrToInt(FuncPtr, PtrDiffTy);
}
static llvm::Value *BuildVirtualCall(CodeGenFunction &CGF, uint64_t VTableIndex,
llvm::Value *This, const llvm::Type *Ty) {
Ty = Ty->getPointerTo()->getPointerTo()->getPointerTo();
@ -400,6 +362,13 @@ void CGCXXABI::EmitNullMemberFunctionPointer(CodeGenFunction &CGF,
ErrorUnsupportedABI(CGF, "null member function pointers");
}
void CGCXXABI::EmitMemberFunctionPointer(CodeGenFunction &CGF,
const CXXMethodDecl *MD,
llvm::Value *DestPtr,
bool VolatileDest) {
ErrorUnsupportedABI(CGF, "member function pointers");
}
llvm::Constant *
CGCXXABI::EmitMemberFunctionPointerConversion(llvm::Constant *C,
const CastExpr *E) {
@ -411,6 +380,10 @@ CGCXXABI::EmitNullMemberFunctionPointer(const MemberPointerType *MPT) {
return 0;
}
llvm::Constant *CGCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
return 0;
}
bool CGCXXABI::RequiresNonZeroInitializer(QualType T) {
return false;
}

7
clang/lib/CodeGen/CGCXXABI.h
View File

@ -22,6 +22,7 @@ namespace llvm {
namespace clang {
class CastExpr;
class CXXMethodDecl;
class CXXRecordDecl;
class MemberPointerType;
class QualType;
@ -70,6 +71,12 @@ public:
virtual llvm::Constant *
EmitNullMemberFunctionPointer(const MemberPointerType *MPT);
virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD);
virtual void EmitMemberFunctionPointer(CodeGenFunction &CGF,
const CXXMethodDecl *MD,
llvm::Value *DestPtr,
bool VolatileDest);
};
/// Creates an instance of a C++ ABI class.

20
clang/lib/CodeGen/CGExprAgg.cpp
View File

@ -364,9 +364,8 @@ void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) {
// We have a member function pointer.
const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
(void) MPT;
assert(MPT->getPointeeType()->isFunctionProtoType() &&
assert(E->getType()->getAs<MemberPointerType>()
->getPointeeType()->isFunctionProtoType() &&
"Unexpected member pointer type!");
// The creation of member function pointers has no side effects; if
@ -375,20 +374,9 @@ void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) {
return;
const DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr());
const CXXMethodDecl *MD =
cast<CXXMethodDecl>(DRE->getDecl())->getCanonicalDecl();
const CXXMethodDecl *MD = cast<CXXMethodDecl>(DRE->getDecl());
const llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr");
llvm::Value *FuncPtr = CGF.CGM.GetCXXMemberFunctionPointerValue(MD);
Builder.CreateStore(FuncPtr, DstPtr, VolatileDest);
llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "dst.adj");
// The adjustment will always be 0.
Builder.CreateStore(llvm::ConstantInt::get(PtrDiffTy, 0), AdjPtr,
VolatileDest);
CGF.CGM.getCXXABI().EmitMemberFunctionPointer(CGF, MD, DestPtr, VolatileDest);
}
void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {

17
clang/lib/CodeGen/CGExprConstant.cpp
View File

@ -455,22 +455,7 @@ public:
}
llvm::Constant *EmitMemberFunctionPointer(CXXMethodDecl *MD) {
assert(MD->isInstance() && "Member function must not be static!");
MD = MD->getCanonicalDecl();
const llvm::Type *PtrDiffTy =
CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
llvm::Constant *Values[2];
Values[0] = CGM.GetCXXMemberFunctionPointerValue(MD);
// The adjustment will always be 0.
Values[1] = llvm::ConstantInt::get(PtrDiffTy, 0);
return llvm::ConstantStruct::get(CGM.getLLVMContext(),
Values, 2, /*Packed=*/false);
return CGM.getCXXABI().EmitMemberFunctionPointer(MD);
}
llvm::Constant *VisitUnaryAddrOf(UnaryOperator *E) {

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

@ -371,10 +371,6 @@ public:
llvm::GlobalValue *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType Type);
// GetCXXMemberFunctionPointerValue - Given a method declaration, return the
// integer used in a member function pointer to refer to that value.
llvm::Constant *GetCXXMemberFunctionPointerValue(const CXXMethodDecl *MD);
/// getBuiltinLibFunction - Given a builtin id for a function like
/// "__builtin_fabsf", return a Function* for "fabsf".
llvm::Value *getBuiltinLibFunction(const FunctionDecl *FD,

106
clang/lib/CodeGen/ItaniumCXXABI.cpp
View File

@ -66,6 +66,16 @@ public:
llvm::Constant *EmitNullMemberFunctionPointer(const MemberPointerType *MPT);
void EmitMemberFunctionPointer(CodeGenFunction &CGF,
const CXXMethodDecl *MD,
llvm::Value *Dest,
bool VolatileDest);
llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD);
private:
void GetMemberFunctionPointer(const CXXMethodDecl *MD,
llvm::Constant *(&Array)[2]);
};
class ARMCXXABI : public ItaniumCXXABI {
@ -82,6 +92,62 @@ CodeGen::CGCXXABI *CodeGen::CreateARMCXXABI(CodeGenModule &CGM) {
return new ARMCXXABI(CGM);
}
void ItaniumCXXABI::GetMemberFunctionPointer(const CXXMethodDecl *MD,
llvm::Constant *(&MemPtr)[2]) {
assert(MD->isInstance() && "Member function must not be static!");
MD = MD->getCanonicalDecl();
CodeGenTypes &Types = CGM.getTypes();
const llvm::Type *ptrdiff_t =
Types.ConvertType(CGM.getContext().getPointerDiffType());
// Get the function pointer (or index if this is a virtual function).
if (MD->isVirtual()) {
uint64_t Index = CGM.getVTables().getMethodVTableIndex(MD);
// FIXME: We shouldn't use / 8 here.
uint64_t PointerWidthInBytes =
CGM.getContext().Target.getPointerWidth(0) / 8;
uint64_t VTableOffset = (Index * PointerWidthInBytes);
if (IsARM) {
// ARM C++ ABI 3.2.1:
// This ABI specifies that adj contains twice the this
// adjustment, plus 1 if the member function is virtual. The
// least significant bit of adj then makes exactly the same
// discrimination as the least significant bit of ptr does for
// Itanium.
MemPtr[0] = llvm::ConstantInt::get(ptrdiff_t, VTableOffset);
MemPtr[1] = llvm::ConstantInt::get(ptrdiff_t, 1);
} else {
// Itanium C++ ABI 2.3:
// For a virtual function, [the pointer field] is 1 plus the
// virtual table offset (in bytes) of the function,
// represented as a ptrdiff_t.
MemPtr[0] = llvm::ConstantInt::get(ptrdiff_t, VTableOffset + 1);
MemPtr[1] = llvm::ConstantInt::get(ptrdiff_t, 0);
}
} else {
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *Ty;
// Check whether the function has a computable LLVM signature.
if (!CodeGenTypes::VerifyFuncTypeComplete(FPT)) {
// The function has a computable LLVM signature; use the correct type.
Ty = Types.GetFunctionType(Types.getFunctionInfo(MD), FPT->isVariadic());
} else {
// Use an arbitrary non-function type to tell GetAddrOfFunction that the
// function type is incomplete.
Ty = ptrdiff_t;
}
llvm::Constant *Addr = CGM.GetAddrOfFunction(MD, Ty);
MemPtr[0] = llvm::ConstantExpr::getPtrToInt(Addr, ptrdiff_t);
MemPtr[1] = llvm::ConstantInt::get(ptrdiff_t, 0);
}
}
/// In the Itanium and ARM ABIs, method pointers have the form:
/// struct { ptrdiff_t ptr; ptrdiff_t adj; } memptr;
///
@ -231,6 +297,13 @@ void ItaniumCXXABI::EmitMemberFunctionPointerConversion(CodeGenFunction &CGF,
CGF.CGM.GetNonVirtualBaseClassOffset(DerivedDecl,
E->path_begin(),
E->path_end())) {
// The this-adjustment is left-shifted by 1 on ARM.
if (IsARM) {
uint64_t Offset = cast<llvm::ConstantInt>(Adj)->getZExtValue();
Offset <<= 1;
Adj = llvm::ConstantInt::get(Adj->getType(), Offset);
}
if (DerivedToBase)
SrcAdj = Builder.CreateSub(SrcAdj, Adj, "adj");
else
@ -265,6 +338,13 @@ ItaniumCXXABI::EmitMemberFunctionPointerConversion(llvm::Constant *C,
// If there's no offset, we're done.
if (!Offset) return C;
// The this-adjustment is left-shifted by 1 on ARM.
if (IsARM) {
uint64_t OffsetV = cast<llvm::ConstantInt>(Offset)->getZExtValue();
OffsetV <<= 1;
Offset = llvm::ConstantInt::get(Offset->getType(), OffsetV);
}
llvm::ConstantStruct *CS = cast<llvm::ConstantStruct>(C);
llvm::Constant *Values[2] = {
@ -300,6 +380,32 @@ ItaniumCXXABI::EmitNullMemberFunctionPointer(const MemberPointerType *MPT) {
return CGM.EmitNullConstant(QualType(MPT, 0));
}
llvm::Constant *
ItaniumCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
llvm::Constant *Values[2];
GetMemberFunctionPointer(MD, Values);
return llvm::ConstantStruct::get(CGM.getLLVMContext(),
Values, 2, /*Packed=*/false);
}
void ItaniumCXXABI::EmitMemberFunctionPointer(CodeGenFunction &CGF,
const CXXMethodDecl *MD,
llvm::Value *DestPtr,
bool VolatileDest) {
llvm::Constant *Values[2];
GetMemberFunctionPointer(MD, Values);
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "memptr.ptr");
Builder.CreateStore(Values[0], DstPtr, VolatileDest);
llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "memptr.adj");
Builder.CreateStore(Values[1], AdjPtr, VolatileDest);
}
bool ItaniumCXXABI::RequiresNonZeroInitializer(QualType T) {
return CGM.getTypes().ContainsPointerToDataMember(T);
}

2
clang/lib/Frontend/ASTUnit.cpp
View File

@ -484,7 +484,7 @@ ASTUnit *ASTUnit::LoadFromASTFile(const std::string &Filename,
// FIXME: This is broken, we should store the TargetOptions in the AST file.
TargetOptions TargetOpts;
TargetOpts.ABI = "";
TargetOpts.CXXABI = "itanium";
TargetOpts.CXXABI = "";
TargetOpts.CPU = "";
TargetOpts.Features.clear();
TargetOpts.Triple = TargetTriple;

10
clang/lib/Frontend/CompilerInvocation.cpp
View File

@ -713,8 +713,10 @@ static void TargetOptsToArgs(const TargetOptions &Opts,
Res.push_back("-target-linker-version");
Res.push_back(Opts.LinkerVersion);
}
Res.push_back("-cxx-abi");
Res.push_back(Opts.CXXABI);
if (!Opts.CXXABI.empty()) {
Res.push_back("-cxx-abi");
Res.push_back(Opts.CXXABI);
}
for (unsigned i = 0, e = Opts.Features.size(); i != e; ++i) {
Res.push_back("-target-feature");
Res.push_back(Opts.Features[i]);
@ -1471,10 +1473,6 @@ static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args) {
// Use the host triple if unspecified.
if (Opts.Triple.empty())
Opts.Triple = llvm::sys::getHostTriple();
// Use the Itanium C++ ABI if unspecified.
if (Opts.CXXABI.empty())
Opts.CXXABI = "itanium";
}
//

20
clang/test/CodeGenCXX/member-function-pointers.cpp
View File

@ -1,5 +1,6 @@
// RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin9 | FileCheck %s
// RUN: %clang_cc1 %s -emit-llvm -o - -triple=i386-apple-darwin9 | FileCheck -check-prefix LP32 %s
// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv7-unknown-unknown | FileCheck -check-prefix ARM %s
struct A { int a; void f(); virtual void vf1(); virtual void vf2(); };
struct B { int b; virtual void g(); };
@ -190,3 +191,22 @@ namespace PR7027 {
struct X { void test( ); };
void testX() { &X::test; }
}
namespace test7 {
struct A { void foo(); virtual void vfoo(); };
struct B { void foo(); virtual void vfoo(); };
struct C : A, B { void foo(); virtual void vfoo(); };
// CHECK-ARM: @_ZN5test74ptr0E = global {{.*}} { i32 ptrtoint ({{.*}}* @_ZN5test71A3fooEv to i32), i32 0 }
// CHECK-ARM: @_ZN5test74ptr1E = global {{.*}} { i32 ptrtoint ({{.*}}* @_ZN5test71B3fooEv to i32), i32 8 }
// CHECK-ARM: @_ZN5test74ptr2E = global {{.*}} { i32 ptrtoint ({{.*}}* @_ZN5test71C3fooEv to i32), i32 0 }
// CHECK-ARM: @_ZN5test74ptr3E = global {{.*}} { i32 0, i32 1 }
// CHECK-ARM: @_ZN5test74ptr4E = global {{.*}} { i32 0, i32 9 }
// CHECK-ARM: @_ZN5test74ptr5E = global {{.*}} { i32 0, i32 1 }
void (C::*ptr0)() = &A::foo;
void (C::*ptr1)() = &B::foo;
void (C::*ptr2)() = &C::foo;
void (C::*ptr3)() = &A::vfoo;
void (C::*ptr4)() = &B::vfoo;
void (C::*ptr5)() = &C::vfoo;
}