Hi, I noticed that currently the tsan pass does not instrument bit fileld accesses or unaligned data. Thus some race conditions are not found by the sanitizer.
Furthermore the function __tsan_vptr_update is not called with the correct
parameters.
This patch uses two already existing interfaces for unaligned or bit field
accessses,
__tsan_read_range and __tsan_write_range, and fixes the parameters of the
__tsan_vptr_update
function.
As a little surprise, the test case g++.dg/tsan/aligned_vs_unaligned_race.C
started to fail at -O2
with this patch, but actually that was due to a combination of invalid C code
and inverted logic
in the test case. So actually that test was failing all the time, because TSAN
cannot find
the race condition because __tsan_write8 should only be called with aligned
addresses.
Boot-strapped and reggession tested on x86_64-linux-gnu.
OK for trunk?
Thanks
Bernd.
gcc/ChangeLog:
2014-12-29 Bernd Edlinger <bernd.edlin...@hotmail.de>
Instrument bit field and unaligned accesses for TSAN.
* sanitizer.def (BUILT_IN_TSAN_READ_RANGE): New built-in function.
(BUILT_IN_TSAN_WRITE_RANGE): New built-in function.
* tsan.c (instrument_expr): Handle COMPONENT_REF and BIT_FIELD_REF.
Use BUILT_IN_TSAN_READ_RANGE and BUILT_IN_TSAN_WRITE_RANGE for
unaligned memory regions. Pass "rhs" to BUILT_IN_TSAN_VPTR_UPDATE.
testsuite/ChangeLog:
2014-12-29 Bernd Edlinger <bernd.edlin...@hotmail.de>
* c-c++-common/tsan/bitfield_race.c: New testcase.
* g++.dg/tsan/aligned_vs_unaligned_race.C: Fixed.
patch-tsan-bitfields.diff
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