[libc-commits] [clang] [libc] [libc] Remove atomic alignment diagnostics globally (PR #96803)

[Joseph Huber via libc-commits]

https://github.com/jhuber6 updated https://github.com/llvm/llvm-project/pull/96803

>From 66b82f970e8914a920259dd12decd65fbb325356 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Wed, 26 Jun 2024 12:58:22 -0500
Subject: [PATCH] [libc] Remove atomic alignment diagnostics globally

Summary:
These warnings mean that it will lower to a libcall. Previously we just
disabled it locally, which didn't work with GCC. This patch does it
globally in the compiler options if the compiler is clang.
---
 clang/cmake/caches/Fuchsia-stage2.cmake | 2 +-
 libc/src/stdlib/rand.cpp                | 6 ------
 libc/src/stdlib/srand.cpp               | 6 ------
 3 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/clang/cmake/caches/Fuchsia-stage2.cmake b/clang/cmake/caches/Fuchsia-stage2.cmake
index a573ec5473210..9892b5d58e719 100644
--- a/clang/cmake/caches/Fuchsia-stage2.cmake
+++ b/clang/cmake/caches/Fuchsia-stage2.cmake
@@ -321,7 +321,7 @@ foreach(target armv6m-unknown-eabi;armv7m-unknown-eabi;armv8m-unknown-eabi)
   set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY CACHE STRING "")
   foreach(lang C;CXX;ASM)
-    set(RUNTIMES_${target}_CMAKE_${lang}_FLAGS "--target=${target} -mthumb" CACHE STRING "")
+    set(RUNTIMES_${target}_CMAKE_${lang}_FLAGS "--target=${target} -mthumb -Wno-atomic-alignment" CACHE STRING "")
   endforeach()
   foreach(type SHARED;MODULE;EXE)
     set(RUNTIMES_${target}_CMAKE_${type}_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
diff --git a/libc/src/stdlib/rand.cpp b/libc/src/stdlib/rand.cpp
index 8f2ae90336d51..ff3875c2f6959 100644
--- a/libc/src/stdlib/rand.cpp
+++ b/libc/src/stdlib/rand.cpp
@@ -13,10 +13,6 @@
 
 namespace LIBC_NAMESPACE {
 
-// Silence warnings on targets with slow atomics.
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Watomic-alignment"
-
 // An implementation of the xorshift64star pseudo random number generator. This
 // is a good general purpose generator for most non-cryptographics applications.
 LLVM_LIBC_FUNCTION(int, rand, (void)) {
@@ -33,6 +29,4 @@ LLVM_LIBC_FUNCTION(int, rand, (void)) {
   }
 }
 
-#pragma GCC diagnostic pop
-
 } // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdlib/srand.cpp b/libc/src/stdlib/srand.cpp
index 681aad8fac4e8..21166c7a6754e 100644
--- a/libc/src/stdlib/srand.cpp
+++ b/libc/src/stdlib/srand.cpp
@@ -12,14 +12,8 @@
 
 namespace LIBC_NAMESPACE {
 
-// Silence warnings on targets with slow atomics.
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Watomic-alignment"
-
 LLVM_LIBC_FUNCTION(void, srand, (unsigned int seed)) {
   rand_next.store(seed, cpp::MemoryOrder::RELAXED);
 }
 
-#pragma GCC diagnostic pop
-
 } // namespace LIBC_NAMESPACE