MC, COFF: Use relocations for function references inside the section

Referencing one symbol from another in the same section does not
generally require a relocation.  However, the MS linker has a feature
called /INCREMENTAL which enables incremental links.  It achieves this
by creating thunks to the actual function and redirecting all
relocations to point to the thunk.

This breaks down with the old scheme if you have a function which
references, say, itself.  On x86_64, we would use %rip relative
addressing to reference the start of the function from out current
position.  This would lead to miscompiles because other references might
reference the thunk instead, breaking function pointer equality.

This fixes PR21520.

llvm-svn: 221678

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/MC/WinCOFFStreamer.cpp b/llvm/lib/MC/WinCOFFStreamer.cpp
index 32813a1d263..6a8054d7486 100644
--- a/llvm/lib/MC/WinCOFFStreamer.cpp
+++ b/llvm/lib/MC/WinCOFFStreamer.cpp
@@ -133,7 +133,7 @@ void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
   if (!CurSymbol)
     FatalError("storage class specified outside of symbol definition");
 
-  if (StorageClass & ~0xff)
+  if (StorageClass & ~COFF::SSC_Invalid)
     FatalError(Twine("storage class value '") + itostr(StorageClass) +
                "' out of range");