The BinaryHolder would query the archive member MemoryBuffer name
to check if the current open archive also contains the next requested
objectfile. This comparison was using a StringRef to a temporary
buffer. It only happened with fat archives. This commit adds long-lived
storage along with the MemoryBuffers for the fat archive filename.
The added test would fail during an ASAN build without the fix.
llvm-svn: 268924
Frederic Riss