On 25 Nov 2015, at 20:13 , Alexey Samsonov <vonos...@gmail.com<mailto:vonos...@gmail.com>> wrote:
On Wed, Nov 25, 2015 at 4:12 AM, Schlottke-Lakemper, Michael <m.schlottke-lakem...@aia.rwth-aachen.de<mailto:m.schlottke-lakem...@aia.rwth-aachen.de>> wrote: Thus I tried to compile a complete LLVM/Clang stack (with compiler-rt, libcxx, libcxxabi, libomp) using -DLLVM_USE_SANITIZER=MemoryWithOrigins. However, this did not work either, as apparently during the compilation process the memory sanitizer already comes to life and complains about use-of-unitialized values… Thus this approach seems to be a dead end. Michael On 24 Nov 2015, at 15:28 , Michael Schlottke-Lakemper <m.schlottke-lakem...@aia.rwth-aachen.de<mailto:m.schlottke-lakem...@aia.rwth-aachen.de>> wrote: Hi folks, When running our msan-instrumented simulation program, instead of a proper output I get the following error: ==12089==WARNING: MemorySanitizer: use-of-uninitialized-value ==12089==WARNING: Can't read from symbolizer at fd 14 /pds/opt/llvm/bin/llvm-symbolizer: symbol lookup error: /pds/opt/libcxx-20151121-r253770-clang-msan/lib/libc++abi.so.1: undefined symbol: __msan_origin_tls ==12089==WARNING: external symbolizer didn't start up correctly! My setup for using the memory sanitizer is as follows: - compile libc++/libc++abi with -fsanitize=memory - compile test program with normal (=uninstrumented) LLVM/Clang installation using -fsanitize=memory - put instrumented libcxx/libcxxabi library dirs into LD_LIBRARY_PATH Can you pass -Wl,-rpath when you link your executable, to specify the path to instrumented libc++/libc++abi? Yes, and if I do that together with setting LD_LIBRARY_PATH=“”, it works, thanks. Why do you need to clear LD_LIBRARY_PATH to run MSan? What libraries from LLVM lib dir harm running the MSan-ified executalbe? I thought that if you set rpath to correct path with instrumented libraries it should be enough… Right now I have the problem that by default, LD_LIBRARY_PATH includes a directory with libc++/libc++abi in it. However, when running msan-instrumented executables to test them, the executable should pick up msan-instrumented versions of libc++/libc++abi while the subsequently used llvm-symbolizer needs to pick up the uninstrumented versions (otherwise I get the above-mentioned errors). Setting rpath is not enough, since the presence of libc++/libc++abi in LD_LIBRARY_PATH will override it. Compiling llvm-symbolizer in a way that it is able to run with msan-instrumented libc++ might be an option, but I don’t know how to do that (other than compiling all of LLVM with msan, which does not work either). One possible workaround that I have been using is to create a shell script, call it “llvm-symbolizer”, put LD_LIBRARY_PATH="$LLVM_DIR/lib:$LD_LIBRARY_PATH" $LLVM_DIR/bin/llvm-symbolizer $* in it, and make sure that it is on the PATH before the actual llvm-symbolizer executable (which is located in LLVM_DIR/bin). However, this is clearly a workaround and I am looking for a more robust and more “canonical” solution. Any suggestions? Michael
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