Calculate offset correctly when taking the address of a virtual member function.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 81209da..a358b54 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -418,8 +418,11 @@
// Get the function pointer (or index if this is a virtual function).
if (MD->isVirtual()) {
uint64_t Index = CGM.getVtableInfo().getMethodVtableIndex(MD);
-
- // The pointer is 1 + the virtual table offset in bytes.
+
+ // 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.
Values[0] = llvm::ConstantInt::get(PtrDiffTy, (Index * 8) + 1);
} else {
llvm::Constant *FuncPtr = CGM.GetAddrOfFunction(MD);