[compiler-rt] 0f59b8d - Fix improper alignment of static buffer for placement-new of BufferQueue (#152408)

[via llvm-commits]

Author: Slava Gurevich
Date: 2025-08-08T09:36:22-07:00
New Revision: 0f59b8d4e3f8081c69b46f4693536e118fc0e9e6

URL: https://github.com/llvm/llvm-project/commit/0f59b8d4e3f8081c69b46f4693536e118fc0e9e6
DIFF: https://github.com/llvm/llvm-project/commit/0f59b8d4e3f8081c69b46f4693536e118fc0e9e6.diff

LOG: Fix improper alignment of static buffer for placement-new of BufferQueue (#152408)

No behavioral change, but eliminates potential UB in strict-alignment
systems.

The previous commit (llvm#94171) bulk-updated alignment usage to C++23
spec, but missed this occurrence.

Added: 
    

Modified: 
    compiler-rt/lib/xray/xray_fdr_logging.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/xray/xray_fdr_logging.cpp b/compiler-rt/lib/xray/xray_fdr_logging.cpp
index 7def3565d56ab..977a0b9b87f4e 100644
--- a/compiler-rt/lib/xray/xray_fdr_logging.cpp
+++ b/compiler-rt/lib/xray/xray_fdr_logging.cpp
@@ -73,7 +73,7 @@ static_assert(std::is_trivially_destructible<ThreadLocalData>::value,
 static pthread_key_t Key;
 
 // Global BufferQueue.
-static std::byte BufferQueueStorage[sizeof(BufferQueue)];
+alignas(BufferQueue) static std::byte BufferQueueStorage[sizeof(BufferQueue)];
 static BufferQueue *BQ = nullptr;
 
 // Global thresholds for function durations.