[Bug sanitizer/59061] Port leaksanitizer

[kcc at gcc dot gnu.org]

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

--- Comment #22 from Kostya Serebryany <kcc at gcc dot gnu.org> ---
(In reply to Joost VandeVondele from comment #21)
> (In reply to Kostya Serebryany from comment #20)
> > > 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.
> > 
> > that's with -fsanitize=address?
> 
> No, full asan is about 100% (or more) overhead for us (I guess the overhead
> depends on the optimization level, but roughly speaking). This is only the
> leak checking (as obtained by only linking with -fsanitize=address and
> exporting the flag).

That's what I meant. 
-fsanitize=address applied at compile time adds expensive instrumentation. 
-fsanitize=address applied at link time adds only expensive asan's allocator. 
-fsanitize=leak will add a cheaper allocator (but less tested)