[LLVMdev] MemorySanitizer, a tool that finds uninitialized reads and more

[Kostya Serebryany]

On Mon, Jun 18, 2012 at 5:43 PM, Joerg Sonnenberger <joerg at britannica.bec.de
> wrote:

> On Mon, Jun 18, 2012 at 05:19:11PM +0400, Kostya Serebryany wrote:
> > On Mon, Jun 18, 2012 at 5:07 PM, Joerg Sonnenberger <
> joerg at britannica.bec.de
> > > wrote:
> >
> > > On Mon, Jun 18, 2012 at 02:39:34PM +0400, Kostya Serebryany wrote:
> > > > Another difference from Memcheck is that we propose to use 8 shadow
> bits
> > > > per byte of application memory and use a
> > > > direct shadow mapping (for 64-bit linux that is just clearing 46-th
> bit
> > > of
> > > > the application memory address).
> > > > This greatly simplifies the instrumentation code and avoids races on
> > > shadow
> > > > updates
> > > > (Memcheck is single-threaded so races are not a concern there.
> > > > Memcheck uses 2 shadow bits per byte with a slow path storage that
> uses 8
> > > > bits per byte).
> > >
> > > Can you make it possible for ASAN to share the same layout?
> >
> >
> > Not sure I understand you. What layout?
>
> Shadow memory.
>

yes, asan and msan shadow could co-exist, at least on 64-bit linux with
disabled ASLR.
But the problem is that the memory overheads will multiply -- the combined
tool will be more expensive to use
than two separate tools together.

--kcc



> Joerg
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