From: Hans Wennborg <hans@hanshq.net>
Date: Sun, 7 Sep 2014 04:24:31 +0000 (+0000)
Subject: BumpPtrAllocator: do the size check without moving any pointers
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=4f240010fdea1fcbe7dac3c8e9ebad082e4036c2;hp=4f240010fdea1fcbe7dac3c8e9ebad082e4036c2

BumpPtrAllocator: do the size check without moving any pointers

Instead of aligning and moving the CurPtr forward, and then comparing
with End, simply calculate how much space is needed, and compare that
to how much is available.

Hopefully this avoids any doubts about comparing addresses possibly
derived from past the end of the slab array, overflowing, etc.

Also add a test where aligning CurPtr would move it past End.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217330 91177308-0d34-0410-b5e6-96231b3b80d8
---