Add a sanity check in MemoryBuffer::getOpenFile() to make sure we don't hang
if the passed in FileSize is inaccurate.

rdar://11034179

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152662 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed