tree e8f19ff802589c94b813a3ca9590abbf929390a4
parent 70862df7ebde56596a05a7f5f5b7b20fa610be84
author Zachary Turner <zturner@google.com> 1496450015 +0000
committer Zachary Turner <zturner@google.com> 1496450015 +0000

[PDB] Fix use after free.

Previously MappedBlockStream owned its own BumpPtrAllocator that
it would allocate from when a read crossed a block boundary.  This
way it could still return the user a contiguous buffer of the
requested size.  However, It's not uncommon to open a stream, read
some stuff, close it, and then save the information for later.
After all, since the entire file is mapped into memory, the data
should always be available as long as the file is open.

Of course, the exception to this is when the data isn't *in* the
file, but rather in some buffer that we temporarily allocated to
present this contiguous view.  And this buffer would get destroyed
as soon as the strema was closed.

The fix here is to force the user to specify the allocator, this
way it can provide an allocator that has whatever lifetime it
chooses.

Differential Revision: https://reviews.llvm.org/D33858

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304623 91177308-0d34-0410-b5e6-96231b3b80d8