On Wed, Oct 11, 2017 at 03:36:40PM +0200, Martin Liška wrote:
> > std::swap(addr1, addr2); ? I don't see it used in any of libsanitizer
> > though, so not sure if the corresponding STL header is included.
>
> They don't use it anywhere and I had some #include issues. That's why I did
> it manually.
Ok.
> > There are many kinds of shadow memory markings. My thought was that it
> > would start with a quick check, perhaps vectorized by hand (depending on if
> > the arch has unaligned loads maybe without or with a short loop for
>
> Did that, but I have no experience how to make decision about prologue that
> will
> align the pointer? Any examples?
First of all, why are you aligning anything?
> + uptr aligned_addr1 = addr1 & ~(SANITIZER_WORDSIZE/8 - 1); // align addr.
> + uptr aligned_addr2 = addr2 & ~(SANITIZER_WORDSIZE/8 - 1); // align addr.
You want to compare what the pointers point to, not what the aligned pointer
points to.
Actually, looking around, there already is __sanitizer::mem_is_zero
which does what we want.
Or even __asan_region_is_poisoned(addr1, addr2 - addr1).
Jakub
