[LLVMdev] Need help reproducing a sanitizer buildbot failure

[Diego Novillo]

I recently broke a sanitizer buildbot but I am unable to reproduce the
failure. The buildbot that failed is


http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/2959


I looked around in the logs, looking for the config/build commands that
would reproduce the failure. The problem is that the bot seems to be using
a script which I don't have access to (buildbot_bootstrap.sh). So, I looked
for cmake/ninja calls. AFAICT, the bot does a bootstrap and then runs the
testsuite with the final build configured with -DLLVM_USE_SANITIZER=Memory.

I tried that locally, but the build dies very early in tblgen:

FAILED: cd /ssd/dnovillo/llvm/bld/tools/clang/include/clang/Driver &&
/ssd/dnovillo/llvm/bld/bin/llvm-tblgen -gen-opt-parser-defs -I
/ssd/dnovillo/llvm/llvm/tools/clang/include/clang/Driver -I
/ssd/dnovillo/llvm/llvm/lib/Target -I /ssd/dnovillo/llvm/llvm/include
/ssd/dnovillo/llvm/llvm/tools/clang/include/clang/Driver/Options.td -o
/ssd/dnovillo/llvm/bld/tools/clang/include/clang/Driver/Options.inc.tmp
==12630== WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x7f1ea9b01729 (/ssd/dnovillo/llvm/bld/bin/llvm-tblgen+0x8f729)
    #1 0x7f1ea9a9cbe0 (/ssd/dnovillo/llvm/bld/bin/llvm-tblgen+0x2abe0)
    #2 0x7f1ea9f7b69c (/ssd/dnovillo/llvm/bld/bin/llvm-tblgen+0x50969c)
    #3 0x7f1ea82356ff (/lib/x86_64-linux-gnu/libc.so.6+0x216ff)
    #4 0x7f1ea9b01280 (/ssd/dnovillo/llvm/bld/bin/llvm-tblgen+0x8f280)

SUMMARY: MemorySanitizer: use-of-uninitialized-value ??:0 ??
Exiting


I'm not sure how to proceed from here. The bot is clearly building things
in a different way, but I don't know how to duplicate it. Is there a  way
for me to use the same script that the bot is using? What is the general
advice on reproducing buildbot failures?


Thanks. Diego.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140410/0ce6d771/attachment.html>