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meson: Disable GCC's dead store elimination for memory zeroing custom new 

Some classes use custom new operator which zeroes memory, however gcc does
aggressive dead-store elimination which threats all writes to the memory
before the constructor as "dead stores".

For now we disable this optimization.

The new operators in question are declared via:
 DECLARE_RZALLOC_CXX_OPERATORS
 DECLARE_LINEAR_ZALLOC_CXX_OPERATORS

The issue was found with lto builds, however there is no guarantee that
it didn't happen with ordinary ones.

CC: <mesa-stable@lists.freedesktop.org>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2977
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/1358
Signed-off-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5104>
This commit is contained in:
Danylo Piliaiev 2020-05-19 20:35:49 +03:00 committed by Marge Bot
parent a3045cbc97
commit 5500a2b7fc
1 changed files with 5 additions and 0 deletions
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@ -980,6 +980,11 @@ else
'-fno-math-errno',
'-fno-trapping-math',
'-Qunused-arguments',
# Some classes use custom new operator which zeroes memory, however
# gcc does aggressive dead-store elimination which threats all writes
# to the memory before the constructor as "dead stores".
# For now we disable this optimization.
'-flifetime-dse=1',
]
# MinGW chokes on format specifiers and I can't get it all working
if not (cc.get_id() == 'gcc' and host_machine.system() == 'windows')