[Bug sanitizer/59061] Port leaksanitizer

["Joost.VandeVondele at mat dot ethz.ch" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59061

--- Comment #19 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> ---
(In reply to Kostya Serebryany from comment #18)
> I don't think we've measured pure-lsan slowdown, but I expect it to be small.
> asan/lsan bring in a different allocator (malloc/free).
> We tried to make it very fast and our measurements show that's it is close
> to 
> tcmalloc performance (but a bit more greedy in memory).
> It also performs stack unwind on every malloc, so on malloc-intensive apps
> you may see some small slowdown.

I our simulation code, it looks like the overhead for leak checking is about
20%. I haven't done very careful measurements yet, since this is more or less
what we're willing to pay to integrate the (very useful) feature in our testing
setup.