[cfe-users] Errors when trying to use libcxx/libcxxabi with memory sanitizer

Schlottke-Lakemper, Michael via cfe-users cfe-users at lists.llvm.org
Mon Nov 23 11:13:05 PST 2015

> On 23 Nov 2015, at 20:01 , Evgenii Stepanov <eugeni.stepanov at gmail.com> wrote:
> Yes. Effectively you need two environments - one with
> msan-instrumented libraries, and one without. Compilation should
> happen in the latter (unless you want to instrument the compiler which
> is not very productive), and resulting binaries should be run in the
> former.

Ah, thanks a lot. Just to be sure: is it generally OK to compile & link in an environment where ld would e.g. pick up an uninstrumented version of the OpenMPI libraries as long as the correct, instrumented OpenMPI library is in LD_LIBRARY_PATH at runtime?

Sorry for having to ask again


> On Mon, Nov 23, 2015 at 10:50 AM, Schlottke-Lakemper, Michael
> <m.schlottke-lakemper at aia.rwth-aachen.de> wrote:
>>> On 23 Nov 2015, at 18:11 , Evgenii Stepanov <eugeni.stepanov at gmail.com> wrote:
>>> On Mon, Nov 23, 2015 at 12:59 AM, Schlottke-Lakemper, Michael via
>>> cfe-users <cfe-users at lists.llvm.org> wrote:
>>>> Hi folks,
>>>> I'm trying to set up our cluster tool chain to support clang’s memory
>>>> sanitizer for our multiphysics simulation program, but I can’t get it to
>>>> work :-/
>>>> I started with a regularly compiled clang installation (with libcxx,
>>>> libcxxabi, and libomp built in-tree). With this, I compiled all necessary
>>>> third-party libraries with “-O1 -fsanitize=memory” (OpenMPI, FFTW, Parallel
>>>> netCDF). Then, I compiled the libcxx/libcxxabi libraries with msan-support
>>>> by checking out the llvm source and the libcxx/libcxxabi repos into the
>>>> llvm/projects/ directory. I configured them with LLVM_USE_SANITIZER=Memory
>>>> and put the msan-instrumented libraries in the LD_LIBRARY_PATH.
>>>> Finally, I tried to compile our tool, ZFS, with the memory sanitizer enabled
>>>> and linked against the msan-compiled third-party libraries as well as the
>>>> msan-instrumented libcxx/libcxxabi libraries (by putting them in the
>>>> LD_LIBRARY_PATH). However, here I failed: either at configure time or at
>>>> compile time (after doing some LD_LIBRARY_PATH trickery), clang exits with
>>>> the following error:
>>>> /pds/opt/llvm-20151121-r253770/bin/clang++: symbol lookup error:
>>>> /pds/opt/libcxx-msan-20151121-r253770/lib/libc++abi.so.1: undefined symbol:
>>>> __msan_va_arg_overflow_size_tls
>>>> Any suggestions as to what I am doing wrong? Should I put the
>>>> msan-instrumented libcxx in the LD_LIBRARY_PATH after compilation only?
>>> Yes, probably. In this case your compiler, which is not built with
>>> MSan, picked up an instrumented libc++abi.
>>> Sometimes it is convenient to set RPATH on all msan
>>> libraries/executables and avoid LD_LIBRARY_PATH.
>> Thanks for your answer. Unfortunately, I cannot avoid LD_LIBRARY_PATH as it includes our cluster-wide LLVM lib dir by default on all our hosts. Thus setting RPATH at compile/link time will have no effect as there is no way to make it overrule LD_LIBRARY_PATH afaik. Instrumenting all of Clang with MSan seems a bit overkill to me (and does not solve the RPATH/LD_LIBRARY_PATH issue at runtime anyways). I guess I’ll just have to live with manually changing the LD_LIBRARY_PATH after compilation then.
>> Michael

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