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[ms-cxxabi] Emit non-virtual member function pointers 

Without any conversion, this is pretty straightforward.  Most of the
fields can be zeros.  The order is:

- field offset or pointer
- nonvirtual adjustment (for MI functions)
- vbptr offset (for unspecified)
- virtual adjustment offset (for virtual inheritance)

Differential Revision: http://llvm-reviews.chandlerc.com/D699

llvm-svn: 180985
This commit is contained in:
Reid Kleckner 2013-05-03 01:15:11 +00:00
parent a80ea12703
commit 7d0efb57d3
2 changed files with 142 additions and 22 deletions
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105
clang/lib/CodeGen/MicrosoftCXXABI.cpp
View File

@ -139,6 +139,12 @@ private:
llvm::Value *VirtualBaseAdjustmentOffset,
llvm::Value *VBPtrOffset /* optional */);
/// \brief Emits a full member pointer with the fields common to data and
/// function member pointers.
llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
bool IsMemberFunction,
const CXXRecordDecl *RD);
public:
virtual llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT);
@ -148,6 +154,8 @@ public:
virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
CharUnits offset);
virtual llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD);
virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT);
virtual llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
llvm::Value *L,
@ -427,10 +435,9 @@ static bool hasOnlyOneField(MSInheritanceModel Inheritance) {
// Only member pointers to functions need a this adjustment, since it can be
// combined with the field offset for data pointers.
static bool hasNonVirtualBaseAdjustmentField(const MemberPointerType *MPT,
static bool hasNonVirtualBaseAdjustmentField(bool IsMemberFunction,
MSInheritanceModel Inheritance) {
return (MPT->isMemberFunctionPointer() &&
Inheritance >= MSIM_Multiple);
return (IsMemberFunction && Inheritance >= MSIM_Multiple);
}
static bool hasVirtualBaseAdjustmentField(MSInheritanceModel Inheritance) {
@ -472,9 +479,10 @@ MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
else
fields.push_back(CGM.IntTy); // FieldOffset
if (hasVBPtrOffsetField(Inheritance))
if (hasNonVirtualBaseAdjustmentField(MPT->isMemberFunctionPointer(),
Inheritance))
fields.push_back(CGM.IntTy);
if (hasNonVirtualBaseAdjustmentField(MPT, Inheritance))
if (hasVBPtrOffsetField(Inheritance))
fields.push_back(CGM.IntTy);
if (hasVirtualBaseAdjustmentField(Inheritance))
fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
@ -500,9 +508,10 @@ GetNullMemberPointerFields(const MemberPointerType *MPT,
fields.push_back(getAllOnesInt()); // FieldOffset
}
if (hasVBPtrOffsetField(Inheritance))
if (hasNonVirtualBaseAdjustmentField(MPT->isMemberFunctionPointer(),
Inheritance))
fields.push_back(getZeroInt());
if (hasNonVirtualBaseAdjustmentField(MPT, Inheritance))
if (hasVBPtrOffsetField(Inheritance))
fields.push_back(getZeroInt());
if (hasVirtualBaseAdjustmentField(Inheritance))
fields.push_back(getAllOnesInt());
@ -520,27 +529,87 @@ MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
}
llvm::Constant *
MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
CharUnits offset) {
const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
bool IsMemberFunction,
const CXXRecordDecl *RD)
{
MSInheritanceModel Inheritance = RD->getMSInheritanceModel();
// Single inheritance class member pointer are represented as scalars instead
// of aggregates.
if (hasOnlyOneField(Inheritance))
return FirstField;
llvm::SmallVector<llvm::Constant *, 4> fields;
fields.push_back(llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity()));
fields.push_back(FirstField);
if (hasNonVirtualBaseAdjustmentField(IsMemberFunction, Inheritance))
fields.push_back(getZeroInt());
if (hasVBPtrOffsetField(Inheritance)) {
int64_t VBPtrOffset =
getContext().getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
if (VBPtrOffset == -1)
VBPtrOffset = 0;
fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset));
}
assert(!hasNonVirtualBaseAdjustmentField(MPT, Inheritance));
// The virtual base field starts out zero. It is adjusted by conversions to
// member pointer types of a more derived class. See http://llvm.org/PR15713
// The rest of the fields are adjusted by conversions to a more derived class.
if (hasVirtualBaseAdjustmentField(Inheritance))
fields.push_back(getZeroInt());
if (fields.size() == 1)
return fields[0];
return llvm::ConstantStruct::getAnon(fields);
}
llvm::Constant *
MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
CharUnits offset) {
const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
llvm::Constant *FirstField =
llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD);
}
llvm::Constant *
MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
assert(MD->isInstance() && "Member function must not be static!");
MD = MD->getCanonicalDecl();
const CXXRecordDecl *RD = MD->getParent();
CodeGenTypes &Types = CGM.getTypes();
llvm::Constant *FirstField;
if (MD->isVirtual()) {
// FIXME: We have to instantiate a thunk that loads the vftable and jumps to
// the right offset.
FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
} else {
const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
llvm::Type *Ty;
// Check whether the function has a computable LLVM signature.
if (Types.isFuncTypeConvertible(FPT)) {
// The function has a computable LLVM signature; use the correct type.
Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
} else {
// Use an arbitrary non-function type to tell GetAddrOfFunction that the
// function type is incomplete.
Ty = CGM.PtrDiffTy;
}
FirstField = CGM.GetAddrOfFunction(MD, Ty);
FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
}
// The rest of the fields are common with data member pointers.
return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD);
}
llvm::Constant *
MicrosoftCXXABI::EmitMemberPointer(const APValue &MP, QualType MPT) {
// FIXME PR15875: Implement member pointer conversions for Constants.
const CXXRecordDecl *RD = MPT->castAs<MemberPointerType>()->getClass()->getAsCXXRecordDecl();
return EmitFullMemberPointer(llvm::Constant::getNullValue(CGM.VoidPtrTy),
/*IsMemberFunction=*/true, RD);
}
/// Member pointers are the same if they're either bitwise identical *or* both
/// null. Null-ness for function members is determined by the first field,
/// while for data member pointers we must compare all fields.
@ -760,10 +829,10 @@ MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
// We need to extract values.
unsigned I = 0;
FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
if (hasVBPtrOffsetField(Inheritance))
VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
if (hasNonVirtualBaseAdjustmentField(MPT, Inheritance))
NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
if (hasVBPtrOffsetField(Inheritance))
VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
if (hasVirtualBaseAdjustmentField(Inheritance))
VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
}

59
clang/test/CodeGenCXX/microsoft-abi-member-pointers.cpp
View File

@ -1,13 +1,21 @@
// RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -cxx-abi microsoft -triple=i386-pc-win32 | FileCheck %s
struct B1 {
void foo();
int b;
};
struct B2 { };
struct Single : B1 { };
struct Multiple : B1, B2 { };
struct B2 {
void foo();
};
struct Single : B1 {
void foo();
};
struct Multiple : B1, B2 {
void foo();
};
struct Virtual : virtual B1 {
int v;
void foo();
};
struct POD {
@ -30,7 +38,7 @@ struct NonZeroVBPtr : POD, Virtual {
struct Unspecified;
// Check that we can lower the LLVM types and get the initializers right.
// Check that we can lower the LLVM types and get the null initializers right.
int Single ::*s_d_memptr;
int Polymorphic::*p_d_memptr;
int Multiple ::*m_d_memptr;
@ -54,6 +62,49 @@ void (Virtual ::*v_f_memptr)();
// CHECK: @"\01?m_f_memptr@@3P8Multiple@@AEXXZA" = global { i8*, i32 } zeroinitializer, align 4
// CHECK: @"\01?v_f_memptr@@3P8Virtual@@AEXXZA" = global { i8*, i32, i32 } zeroinitializer, align 4
// We can define Unspecified after locking in the inheritance model.
struct Unspecified : Virtual {
void foo();
int u;
};
struct UnspecWithVBPtr;
int UnspecWithVBPtr::*forceUnspecWithVBPtr;
struct UnspecWithVBPtr : B1, virtual B2 {
int u;
void foo();
};
// Test emitting non-virtual member pointers in a non-constexpr setting.
void EmitNonVirtualMemberPointers() {
void (Single ::*s_f_memptr)() = &Single::foo;
void (Multiple ::*m_f_memptr)() = &Multiple::foo;
void (Virtual ::*v_f_memptr)() = &Virtual::foo;
void (Unspecified::*u_f_memptr)() = &Unspecified::foo;
void (UnspecWithVBPtr::*u2_f_memptr)() = &UnspecWithVBPtr::foo;
// CHECK: define void @"\01?EmitNonVirtualMemberPointers@@YAXXZ"() #0 {
// CHECK: alloca i8*, align 4
// CHECK: alloca { i8*, i32 }, align 4
// CHECK: alloca { i8*, i32, i32 }, align 4
// CHECK: alloca { i8*, i32, i32, i32 }, align 4
// CHECK: store i8* bitcast (void (%{{.*}}*)* @"\01?foo@Single@@QAEXXZ" to i8*), i8** %{{.*}}, align 4
// CHECK: store { i8*, i32 }
// CHECK: { i8* bitcast (void (%{{.*}}*)* @"\01?foo@Multiple@@QAEXXZ" to i8*), i32 0 },
// CHECK: { i8*, i32 }* %{{.*}}, align 4
// CHECK: store { i8*, i32, i32 }
// CHECK: { i8* bitcast (void (%{{.*}}*)* @"\01?foo@Virtual@@QAEXXZ" to i8*), i32 0, i32 0 },
// CHECK: { i8*, i32, i32 }* %{{.*}}, align 4
// CHECK: store { i8*, i32, i32, i32 }
// CHECK: { i8* bitcast (void (%{{.*}}*)* @"\01?foo@Unspecified@@QAEXXZ" to i8*), i32 0, i32 0, i32 0 },
// CHECK: { i8*, i32, i32, i32 }* %{{.*}}, align 4
// CHECK: store { i8*, i32, i32, i32 }
// CHECK: { i8* bitcast (void (%{{.*}}*)* @"\01?foo@UnspecWithVBPtr@@QAEXXZ" to i8*),
// CHECK: i32 0, i32 4, i32 0 },
// CHECK: { i8*, i32, i32, i32 }* %{{.*}}, align 4
// CHECK: ret void
// CHECK: }
}
void podMemPtrs() {
int POD::*memptr;
memptr = &POD::a;