[Mesa-dev] [Bug 99527] Provide option for llvmpipe JIT code to run cleanly under valgrind

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=99527

--- Comment #2 from Jose Fonseca <jfonseca at vmware.com> ---
I agree with Roland.  I wouldn't oppose patches fixing these (including
--enable-valgrind build option if performance suffered).


But it won't be trivial.  A big source of issues is the fact that we need
padding to fill the SIMD instructions lanes.  That is, we might need to process
3 floats, but then we allocate tempoary variables worth of 8 floats, where the
last 5 are unitizialied garbagge.  It's not hard to fix this, but there are
hundreds of places this happens.


I suspect that in many cases are actually false positives, ie, limitatio in
valgrind analysis: we use uninitialize memory for temporary calculations, but
they are soon discarded.


How about `--suppressions` option? For llvmpipe there doesn't seem to be many
different stack traces.


Another option is to use call VALGRIND_DISABLE_ERROR_REPORTING /
VALGRIND_ENABLE_ERROR_REPORTING before/after JIT code.


Feel free to experiment with any of the above FWIW.

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