From 9d7c2c5d6f1040299d02934fa975ebb7de1d23ec Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 5 Jul 2024 17:58:23 +0200
Subject: [PATCH] meson: suppress clang's -Watomic-alignment warnings on x86_64
 (#76)

Running `./dev build` on x86_64 with Clang would by default [1][2]
produce about 2200 lines of -Watomic-alignment warnings, like:

    ../src/hatrack/hash/crown.c:416:25: warning: large atomic operation may incur significant performance penalty; the access size (16 bytes) exceeds the max lock-free size (8  bytes) [-Watomic-alignment]
      416 |         record        = atomic_read(&cur->record);
          |                         ^
    ../include/hatrack/hatomic.h:35:24: note: expanded from macro 'atomic_read'
       35 | #define atomic_read(x) atomic_load_explicit(x, memory_order_relaxed)
          |                        ^
    /usr/lib/clang/17/include/stdatomic.h:141:30: note: expanded from macro 'atomic_load_explicit'
      141 | #define atomic_load_explicit __c11_atomic_load
          |                              ^

But it's intentional that we use the emulation where it's not supported
in hardware. Suppress those warnings.

Closes: https://github.com/crashappsec/libcon4m/issues/68

[1] https://releases.llvm.org/7.0.0/tools/clang/docs/DiagnosticsReference.html#watomic-alignment
[2] https://releases.llvm.org/18.1.8/tools/clang/docs/DiagnosticsReference.html#watomic-alignment
---
 meson.build | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/meson.build b/meson.build
index e53711e9..ccfb305e 100644
--- a/meson.build
+++ b/meson.build
@@ -29,6 +29,10 @@ c_args        = ['-Wextra',
                   '-fno-omit-frame-pointer',
                   ]
 
+if (host_machine.cpu_family() == 'x86_64' and cc.get_id() == 'clang')
+  c_args    = c_args + ['-Wno-atomic-alignment']
+endif
+
 if (host_machine.system() == 'darwin')
   using_osx  = true
   link_args  = ['-target',