[llvm] r180094 - Tell MSan that memory initialized by libz is valid

[Reid Kleckner]

On Thu, Apr 25, 2013 at 2:06 PM, Nick Lewycky <nicholas at mxc.ca> wrote:
> On 04/23/2013 05:17 AM, Alexey Samsonov wrote:
>>
>> Author: samsonov
>> Date: Tue Apr 23 07:17:46 2013
>> New Revision: 180094
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=180094&view=rev
>> Log:
>> Tell MSan that memory initialized by libz is valid
>
>
> Why doesn't msan instrument this correctly? Or is libz not initializing all
> this memory?

LLVM is using libz installed on the system, so it's not compiled with
msan.  Therefore msan can't see it initialize the memory.  One way to
solve this is to write custom interceptors around the interfaces that
mark output buffers and parameters as initialized.

The alternative is to compile the world, which Evgeniy was pretty much
able to do for LLVM until libz was added.