MS ABI: Update the thunk linkage computation

As suggested by Reid:

 - class has GVA_Internal linkage -> internal
 - thunk has return adjustment -> weak_odr, to handle evil corner case [1]
 - all other normal methods -> linkonce_odr

 1. Evil corner case:

  struct Incomplete;
  struct A { int a; virtual A *bar(); };
  struct B { int b; virtual B *foo(Incomplete); };
  struct C : A, B { int c; virtual C *foo(Incomplete); };
  C c;

Here, the thunk for C::foo() will be emitted when C::foo() is defined, which
might be in a different translation unit, so it needs to be weak_odr.

Differential Revision: http://reviews.llvm.org/D3992

llvm-svn: 210368

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp b/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
index 6ef31769350..4ce4e9c2e17 100644
--- a/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
+++ b/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
@@ -145,7 +145,7 @@ struct X: virtual C {
   // MANGLING-DAG: @"\01??_7X@Test4@@6B@"
 
   // Also check the mangling of the thunk.
-  // MANGLING-DAG: define weak x86_thiscallcc void @"\01?f@C@@WPPPPPPPI@AEXXZ"
+  // MANGLING-DAG: define linkonce_odr x86_thiscallcc void @"\01?f@C@@WPPPPPPPI@AEXXZ"
 };
 
 X::X() {}