[cfe-dev] i386 -faddress-sanitizer

[Kostya Serebryany]

On Thu, Oct 18, 2012 at 7:00 PM, Carsten Mattner
<carstenmattner at gmail.com>wrote:

> On Thu, Oct 18, 2012 at 4:49 PM, Kostya Serebryany <kcc at google.com> wrote:
> > You are linking a shared object, asan.a should not be linked to it.
>
> What should happen instead?
>

nothing. asan.a should be linked only to the main executable.


>
> > Are these all the flags passed to ld?
>
> Yes it's all minus project-specific -l and *.a and *.o args
> I have omitted for the email.
>

don't you have something like -Wl,-z,defs ?
The problem you describe was seen before in the presence of -Wl,-z,defs,
which forces the definitions of all symbols in .so (and __asan* symbols are
not defined).
The solution was to remove -Wl,-z,defs.

--kcc


>
> > On Thu, Oct 18, 2012 at 6:23 PM, Carsten Mattner <
> carstenmattner at gmail.com>
> > wrote:
> >>
> >> On Thu, Oct 18, 2012 at 3:36 PM, Alexander Potapenko <glider at google.com
> >
> >> wrote:
> >> > Can you append -v at the place it's being invoked to check whether the
> >> > contents of LDFLAGS are being actually passed?
> >>
> >> $ clang <INPUT_OBJECTS> -lstdc++ -v -faddress-sanitizer -shared
> >> <PROJECT_FLAGS> -o <SO_FILE>
> >> clang
> >> version 3.2 (http://llvm.org/git/clang.git
> >> 278eafa2cd8296f8128d13c6466a0ace3d03a872)
> >> (http://llvm.org/git/llvm.git
> >> 2360b7ad99eedecaae512373e7be49c2143550cf)
> >> Target: i386-pc-linux-gnu
> >> Thread model: posix
> >>
> >> "/usr/bin/ld" --eh-frame-hdr -m elf_i386 -shared -o <SO_FILE>
> >> /usr/lib/gcc/i686-pc-linux-gnu/4.7.2/../../../crti.o
> >> /usr/lib/gcc/i686-pc-linux-gnu/4.7.2/crtbeginS.o
> >> -L/usr/lib/gcc/i686-pc-linux-gnu/4.7.2
> >> -L/usr/lib/gcc/i686-pc-linux-gnu/4.7.2/../../.. -L/lib -L/usr/lib
> >> <INPUT_OBJECTS> -lstdc++ -lgcc --as-needed -lgcc_s --no-as-needed -lc
> >> -lgcc --as-needed -lgcc_s --no-as-needed
> >> /usr/lib/gcc/i686-pc-linux-gnu/4.7.2/crtendS.o
> >> /usr/lib/gcc/i686-pc-linux-gnu/4.7.2/../../../crtn.o
> >>
> >> I guess the libasan archive should be part of the above call to ld.
> >>
> >> > On Thu, Oct 18, 2012 at 5:33 PM, Carsten Mattner
> >> > <carstenmattner at gmail.com> wrote:
> >> >> On Thu, Oct 18, 2012 at 3:29 PM, Alexander Potapenko wrote:
> >> >>> Are you linking with ld or clang?
> >> >>> -faddress-sanitizer is a Clang flag, so if you're running `ld
> $LDFLAGS
> >> >>> ...` to link your program, it won't work.
> >> >>
> >> >> clang.
> >> >>
> >> >>> On Thu, Oct 18, 2012 at 5:12 PM, Carsten Mattner
> >> >>> <carstenmattner at gmail.com> wrote:
> >> >>>> On Thu, Oct 18, 2012 at 12:27 AM, Eli Friedman wrote:
> >> >>>>> On Wed, Oct 17, 2012 at 1:43 PM, Carsten Mattner
> >> >>>>> <carstenmattner at gmail.com> wrote:
> >> >>>>>> Is it expected that -faddress-sanitizer  does not work on i386
> and
> >> >>>>>> fails
> >> >>>>>> to properly link resulting in errors like 'undefined symbol:
> >> >>>>>> __asan_init'
> >> >>>>>> at runtime?
> >> >>>>>>
> >> >>>>>> I have ./lib/clang/3.2/lib/linux/libclang_rt.asan-i386.a in
> llvm's
> >> >>>>>> installation,
> >> >>>>>> but it doesn't look like it's linked automatically into the
> >> >>>>>> executable.
> >> >>>>>>
> >> >>>>>> CFLAGS:
> >> >>>>>> -faddress-sanitizer -O1 -fno-omit-frame-pointer -g $PROJECT_FLAGS
> >> >>>>>
> >> >>>>> You need to pass in -faddress-sanitizer both when compiling and
> when
> >> >>>>> linking an application.  Try something like
> >> >>>>> "LDFLAGS=-faddress-sanitizer".
> >> >>>>
> >> >>>> Oh that makes a lot of sense and is kind of obvious in hindsight.
> >> >>>> Yet it didn't work in a quick test. Any options I flags to pass for
> >> >>>> verbose printfs to see what's happening you can suggest?
> >> >>>> In the next test I'll also try to explicitly link the libasan
> archive
> >> >>>> manually for ruling out issues with that archive.
> >> >>>> _______________________________________________
> >> >>>> cfe-dev mailing list
> >> >>>> cfe-dev at cs.uiuc.edu
> >> >>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >> >>>
> >> >>>
> >> >>>
> >> >>> --
> >> >>> Alexander Potapenko
> >> >>> Software Engineer
> >> >>> Google Moscow
> >> >
> >> >
> >> >
> >> > --
> >> > Alexander Potapenko
> >> > Software Engineer
> >> > Google Moscow
> >> _______________________________________________
> >> cfe-dev mailing list
> >> cfe-dev at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >
> >
>
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