Summary:
1. llvm-as/llvm-dis tools do not check for input filename length.
2. llvm-dis does not verify the `Streamer` variable against `nullptr` properly, so the `M` variable could be uninitialized (e.g. if the input file does not exist) leading to null dref.
Patch by Lenar Safin!
Reviewers: samsonov
Reviewed By: samsonov
Subscribers: samsonov, llvm-commits
Differential Revision: http://reviews.llvm.org/D9584
llvm-svn: 237051