[cfe-dev] -fsanitize=undefined and shared libraries

[Richard Smith]

Please use SANITIZER_INTERFACE_ATTRIBUTE (defined in
include/sanitizer/common_interface_defs.h). Otherwise, this looks
great, thanks!

On Wed, Jan 9, 2013 at 1:32 PM, Will Dietz <willdtz at gmail.com> wrote:
> The attached patch should fix the issue for you.
>
> Richard, okay to commit?
>
> ~Will
>
> On Wed, Jan 9, 2013 at 6:02 AM, Martin Martin
> <martin at silverliningsystems.com> wrote:
>> Yes, otherwise it wouldn't work when statically linked.
>>
>>
>> On Wed, Jan 9, 2013 at 6:47 AM, Devchandra L Meetei <dlmeetei at gmail.com>
>> wrote:
>>>
>>> Did you got compiler-rt?
>>>
>>>
>>> On Wed, Jan 9, 2013 at 3:53 AM, Martin Martin
>>> <martin at silverliningsystems.com> wrote:
>>>>
>>>> When trying to use -fsanitize=undefined with shared libraries, I get:
>>>>
>>>> /usr/bin/ld: a.out: hidden symbol `__ubsan_handle_float_cast_overflow' in
>>>> /home/clang/build-cmake/bin/../lib/clang/3.2/lib/linux/libclang_rt.ubsan-x86_64.a(ubsan_handlers.cc.o)
>>>> is referenced by DSO
>>>> /usr/bin/ld: final link failed: Bad value
>>>> clang-3: error: linker command failed with exit code 1 (use -v to see
>>>> invocation)
>>>>
>>>> This is with Clang 3.2 compiled from sources using cmake, on Ubuntu
>>>> 12.10.
>>>>
>>>> I'm compiling my files like this:
>>>>
>>>> clang++ -fPIC -fsanitize=undefined undefined.cpp -c -o undefined.o
>>>> clang++ -shared -Wl,-soname,libfoo.so undefined.o -o libfoo.so
>>>> clang++ -fsanitize=undefined main.cpp -c -o main.o
>>>> clang++ -fsanitize=undefined main.o -L. -lfoo
>>>>
>>>> $ cat undefined.cpp
>>>> int cast(float x) {
>>>>     return int(x);
>>>> }
>>>>
>>>> $ cat main.cpp
>>>> #include <cstdlib>
>>>>
>>>> extern int cast(float x);
>>>>
>>>> int main(int argc, char *argv[])
>>>> {
>>>>     if (argc > 1) {
>>>>         return cast(atof(argv[1]));
>>>>     }
>>>>
>>>>     return 1;
>>>> }
>>>>
>>>> If I don't use shared libraries, but instead like the two .o files
>>>> (without the -fPIC), it works fine, I get:
>>>>
>>>> ./a.out 1e10
>>>> <unknown>: fatal error: value 1e+10 is outside the range of representable
>>>> values of type 'int'
>>>> Illegal instruction (core dumped)
>>>>
>>>>
>>>> Any idea what I'm doing wrong?
>>>>
>>>> Thanks,
>>>> Martin
>>>>
>>>> _______________________________________________
>>>> cfe-dev mailing list
>>>> cfe-dev at cs.uiuc.edu
>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>>>
>>>
>>>
>>>
>>> --
>>> Warm Regards
>>> --Dev
>>> OpenPegasus Developer
>>> "It's Always better to try and fail instead of not doing/trying anything"
>>
>>
>>
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>>