[PATCH] D45047: MSan: introduce the conservative assembly handling mode.

[Alexander Potapenko via Phabricator via llvm-commits]

glider marked an inline comment as done.
glider added a comment.

> I think it's OK to enable this feature by default.

I wouldn't haste with that. First, this approach is not strictly better than the existing one, e.g. it may unpoison the memory that wasn't touched in the assembly.
Second, turning this on may break the clients, so we'd better do that in a separate changelist.



================
Comment at: lib/Transforms/Instrumentation/MemorySanitizer.cpp:3110
+          IRB.CreatePointerCast(ShadowPtr, CShadow->getType()->getPointerTo()));
+      if (MS.TrackOrigins)
+        storeOrigin(IRB, Operand, CShadow, getCleanOrigin(), OriginPtr,
----------------
eugenis wrote:
> Origin is meaningless for unpoisoned memory. All this does is potentially destroy origin info for adjacent memory in case of a less than 4 byte store.
Ack.


Repository:
  rL LLVM

https://reviews.llvm.org/D45047