Re: [PATCH] Asan static optimization (draft)

[Yuri Gribov <tetra2005@gmail.com>]

On Thu, Aug 14, 2014 at 8:53 PM, Konstantin Serebryany
<konstantin.s.serebryany@gmail.com> wrote:
> In order for your work to be generally useful, I'd ask several things:
> - Update https://code.google.com/p/address-sanitizer/wiki/CompileTimeOptimizations
> with examples that will be handled

Done (to be honest I only plan to do full redundancy elimination for
now, hoisting would hopefully follow later). Note I'm still
experimenting so there may be some changes in actual implementation.

> - Create small standalone test cases in C
> - Don't put the tests under GPL (otherwise we'll not be able to reuse
> them in LLVM)

I already have a bunch of tests (which I plan to extend further). How
should I submit them s.t. they could be reused by LLVM?

>>> make sure that sanopt performs conservative optimization
> Yes. I don't know a good solution to this problem, which is why we did
> not attack it before.
> Increasing asan speed will save lots of CPU time, but missing a single software
> bug due to an overly aggressive optimization may cost much more.

Yeah. I thought about manually inspecting optimizations that are
performed for some large files (e.g. GCC's asan.c) and maybe doing
some  random verifications of Asan trophies
(http://code.google.com/p/address-sanitizer/wiki/FoundBugs). Ideally
we'd have some test generator but making a reasonable one for C sounds
laughable. Perhaps there is some prior work on verification of Java
range checks optimizers?

-Y