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<div class="">On 25 Nov 2015, at 20:13 , Alexey Samsonov <<a href="mailto:vonosmas@gmail.com" class="">vonosmas@gmail.com</a>> wrote:</div>
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<div class="gmail_quote">On Wed, Nov 25, 2015 at 4:12 AM, Schlottke-Lakemper, Michael<span class="Apple-converted-space"> </span><span dir="ltr" class=""><<a href="mailto:m.schlottke-lakemper@aia.rwth-aachen.de" target="_blank" class="">m.schlottke-lakemper@aia.rwth-aachen.de</a>></span><span class="Apple-converted-space"> </span>wrote:<br class="">
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<div style="word-wrap: break-word;" class="">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.<span class=""><font color="#888888" class="">
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<div class=""><span class=""><font color="#888888" class="">Michael</font></span>
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<div class="">On 24 Nov 2015, at 15:28 , Michael Schlottke-Lakemper <<a href="mailto:m.schlottke-lakemper@aia.rwth-aachen.de" target="_blank" class="">m.schlottke-lakemper@aia.rwth-aachen.de</a>> wrote:</div>
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<div style="word-wrap: break-word;" class="">Hi folks,
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<div class="">When running our msan-instrumented simulation program, instead of a proper output I get the following error:</div>
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<div class="">==12089==WARNING: MemorySanitizer: use-of-uninitialized-value</div>
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<div class="">==12089==WARNING: Can't read from symbolizer at fd 14</div>
<div class="">/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</div>
<div class="">==12089==WARNING: external symbolizer didn't start up correctly!</div>
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<div class="">My setup for using the memory sanitizer is as follows:</div>
<div class="">- compile libc++/libc++abi with -fsanitize=memory</div>
<div class="">- compile test program with normal (=uninstrumented) LLVM/Clang installation using -fsanitize=memory</div>
<div class="">- put instrumented libcxx/libcxxabi library dirs into LD_LIBRARY_PATH</div>
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<div class="">Can you pass -Wl,-rpath when you link your executable, to specify the path to instrumented libc++/libc++abi?</div>
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<div class="">Yes, and if I do that together with setting LD_LIBRARY_PATH=“”, it works, thanks.</div>
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<div class="">Why do you need to clear LD_LIBRARY_PATH to run MSan?</div>
<div class="">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…</div>
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<div>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).</div>
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<div>One possible workaround that I have been using is to create a shell script, call it “llvm-symbolizer”, put</div>
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<div>LD_LIBRARY_PATH="$LLVM_DIR/lib:$LD_LIBRARY_PATH" $LLVM_DIR/bin/llvm-symbolizer $*</div>
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<div>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.</div>
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<div>Any suggestions?</div>
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<div>Michael</div>
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