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Fix another pointer-to-member function miscompile, this time when trying to call a virtual member function. 

llvm-svn: 95307
This commit is contained in:
Anders Carlsson 2010-02-04 17:08:48 +00:00
parent 674cf89301
commit c4325486b9
2 changed files with 37 additions and 11 deletions
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22
clang/lib/CodeGen/CGExprCXX.cpp
View File

@ -159,8 +159,7 @@ CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(RD, FPT),
FPT->isVariadic());
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8Ty(VMContext)->getPointerTo();
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
// Get the member function pointer.
llvm::Value *MemFnPtr =
@ -206,19 +205,20 @@ CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
Builder.CreateCondBr(IsVirtual, FnVirtual, FnNonVirtual);
EmitBlock(FnVirtual);
const llvm::Type *VTableTy =
FTy->getPointerTo()->getPointerTo()->getPointerTo();
const llvm::Type *VtableTy =
FTy->getPointerTo()->getPointerTo();
llvm::Value *VTable = Builder.CreateBitCast(This, VTableTy);
VTable = Builder.CreateLoad(VTable);
llvm::Value *Vtable = Builder.CreateBitCast(This, VtableTy->getPointerTo());
Vtable = Builder.CreateLoad(Vtable);
VTable = Builder.CreateGEP(VTable, FnAsInt, "fn");
Vtable = Builder.CreateBitCast(Vtable, Int8PtrTy);
llvm::Value *VtableOffset =
Builder.CreateSub(FnAsInt, llvm::ConstantInt::get(PtrDiffTy, 1));
// Since the function pointer is 1 plus the virtual table offset, we
// subtract 1 by using a GEP.
VTable = Builder.CreateConstGEP1_64(VTable, (uint64_t)-1);
Vtable = Builder.CreateGEP(Vtable, VtableOffset, "fn");
Vtable = Builder.CreateBitCast(Vtable, VtableTy);
llvm::Value *VirtualFn = Builder.CreateLoad(VTable, "virtualfn");
llvm::Value *VirtualFn = Builder.CreateLoad(Vtable, "virtualfn");
EmitBranch(FnEnd);
EmitBlock(FnNonVirtual);

26
clang/test/CodeGenCXX/member-function-pointer-calls.cpp Normal file
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@ -0,0 +1,26 @@
// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -O3 -o - | FileCheck %s
struct A {
virtual int vf1() { return 1; }
virtual int vf2() { return 2; }
};
int f(A* a, int (A::*fp)()) {
return (a->*fp)();
}
// CHECK: define i32 @_Z2g1v()
int g1() {
A a;
// CHECK: call i32 @_ZN1A3vf1Ev
// CHECK-NEXT: ret i32
return f(&a, &A::vf1);
}
int g2() {
A a;
// CHECK: call i32 @_ZN1A3vf2Ev
// CHECK-NEXT: ret i32
return f(&a, &A::vf2);
}