PKGBUILDs/extra/mesa/0001-meson-Disable-GCC-s-dead-store-elimination-for-memor.patch
2020-05-22 16:08:21 +00:00

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From 979ae78318c3e37cc0e0579b8d1f05c46bb76e7d Mon Sep 17 00:00:00 2001
From: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Date: Tue, 19 May 2020 20:35:49 +0300
Subject: [PATCH] meson: Disable GCC's dead store elimination for memory
zeroing custom new
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
(cherry picked from commit 5500a2b7fc558217bbd4c2a966ab6fcadaed8b3b)
Signed-off-by: Laurent Carlier <lordheavym@gmail.com>
---
meson.build | 5 +++++
1 files changed, 5 insertions(+), 0 deletion(-)
diff --git a/meson.build b/meson.build
index ba4fdb2a59f..434684c8bcc 100644
--- a/meson.build
+++ b/meson.build
@@ -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')
--
2.26.2