On 2023-02-09 18:38, Tyler Retzlaff wrote:
On Thu, Feb 09, 2023 at 09:04:16AM +0000, Bruce Richardson wrote:
On Wed, Feb 08, 2023 at 01:43:38PM -0800, Tyler Retzlaff wrote:
Introduce atomics abstraction that permits optional use of standard C11
atomics when meson is provided the new enable_stdatomics=true option.
Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
---
config/meson.build | 11 ++++
lib/eal/arm/include/rte_atomic_32.h | 6 ++-
lib/eal/arm/include/rte_atomic_64.h | 6 ++-
lib/eal/include/generic/rte_atomic.h | 96 +++++++++++++++++++++++++++++++++-
lib/eal/loongarch/include/rte_atomic.h | 6 ++-
lib/eal/ppc/include/rte_atomic.h | 6 ++-
lib/eal/riscv/include/rte_atomic.h | 6 ++-
lib/eal/x86/include/rte_atomic.h | 8 ++-
meson_options.txt | 2 +
9 files changed, 139 insertions(+), 8 deletions(-)
diff --git a/config/meson.build b/config/meson.build
index 26f3168..25dd628 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -255,6 +255,17 @@ endif
# add -include rte_config to cflags
add_project_arguments('-include', 'rte_config.h', language: 'c')
+stdc_atomics_enabled = get_option('enable_stdatomics')
+dpdk_conf.set('RTE_STDC_ATOMICS', stdc_atomics_enabled)
+
+if stdc_atomics_enabled
+if cc.get_id() == 'gcc' or cc.get_id() == 'clang'
+ add_project_arguments('-std=gnu11', language: 'c')
Is there a reason for using gnu11 on gcc and clang, rather than limiting
ourselves to proper c11 support?
there is code using posix extensions, there are two ways to use them
without emitting warnings.
1. -std=gnu11 (to get C11 with GNU extensions)
-- or --
2. -std=c11 and then in the source files consuming the C11 GNU
extensions do some dance with various GNUC macros before including
various stdxxx.h headers to enable the extensions for the translation
unit.
i vaguely recall that if you try to do a test build with -std=c11 over
the whole tree with meson --werror it will highlight the exact code i'm
talking about.
selfishly i'd be happy to see (2) done and potentially eliminate the use
of the extensions, but i didn't want to be disruptive as a part of this
change.
Some of the GNU extensions are useful, and have no equivalent in C11.
Statement expressions is one example that comes to mind.
I think you can get such code through GCC even with -std=c11, but not if
combined with -pedantic.
