On Thu, Jun 06, 2013 at 01:26:06AM -0700, Andrew Pinski wrote:
> On Thu, Jun 6, 2013 at 1:21 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> > On Thu, Jun 06, 2013 at 11:46:19AM +0400, Konstantin Serebryany wrote:
> >> If we are going to import the ubsan run-time from LLVM's
> >> projects/compiler-rt/lib/ubsan,
> >> we may also need to update the contents of
> >> libsanitizer/sanitizer_common and keep them in sync afterwards.
> >> (ubsan shares few bits of code with asan/tsan/msan)
> >> The simplest way to do that is to extend libsanitizer/merge.sh
> >
> > Sure. I've done so far just a partial merge by hand (only 3 changed files
> > for the minimum of changes required to get ubsan to build), and have tested
> > just
> > that it compiles, not that libubsan actually works.
> >
> > P1 patch is the toplevel stuff to add ubsan into GCC libsanitizer, plus
> > ubsan/Makefile* and ubsan/libtool-version (i.e. gcc owned files).
> > P2 is the actual merge of the ubsan files.
> > P3 is something I'd propose for ubsan upstream, without it g++ warns about
> > __int128 in -pedantic mode.
>
> Is there a reason why ubsan runtime in C++? That seems like a bad
> idea to require linking against libstdc++ when doing development of a
> C only program.
-fsanitize=undefined etc. are debugging modes, not something meant for
release versions of programs, I think it is not a big deal.
C++ is implementation language for the libraries, why exactly we actually
link libasan and libtsan against -lstdc++ I don't really remember, maybe we
don't
have to, it is compiled with -fno-exceptions and doesn't use any libstdc++
symbols. libubsan apparently has two files which actually use some
libstdc++ symbols and are for some C++ sanitization.
BTW, all the libs link against -ldl too (not that big a deal) and -lpthread
(IMHO more serious problem than -lstdc++).
> Also it seems easy enough to write a GCC specific runtime that does
> not depend on the rest of libsanitizer stuff anyways.
We already have libasan and libtsan in gcc, ubsan is just a think layer on
top of the sanitizer_common infrastructure, we'd have to write from scratch
not just the handlers, but some infrastructure too, for what gain?
Jakub
