From e951ffbe576109bf8873eae1e0ee522fca73840c Mon Sep 17 00:00:00 2001
From: wuminghui <wuminghui1412@qq.com>
Date: Tue, 18 Mar 2025 11:50:31 +0800
Subject: [PATCH] Fix compiler optimize thread local variable access
 `bthread_usleep`/`bthread_yield` contains access to TLS variables. In LTO
 mode, exceptions may occur due to cross-module optimization. For example,
 bthread_usleep is inlined into WatchConnections, the compiler(clang-17.0.6)
 cache the address outside the loop, triggering the error mentioned in #2156.

---
 src/bthread/bthread.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/bthread/bthread.cpp b/src/bthread/bthread.cpp
index e124f4bc6f..1ec4faaa91 100644
--- a/src/bthread/bthread.cpp
+++ b/src/bthread/bthread.cpp
@@ -70,6 +70,7 @@ pthread_mutex_t g_task_control_mutex = PTHREAD_MUTEX_INITIALIZER;
 TaskControl* g_task_control = NULL;
 
 extern BAIDU_THREAD_LOCAL TaskGroup* tls_task_group;
+EXTERN_BAIDU_VOLATILE_THREAD_LOCAL(TaskGroup*, tls_task_group);
 extern void (*g_worker_startfn)();
 extern void (*g_tagged_worker_startfn)(bthread_tag_t);
 extern void* (*g_create_span_func)();
@@ -521,7 +522,7 @@ int bthread_timer_del(bthread_timer_t id) {
 }
 
 int bthread_usleep(uint64_t microseconds) {
-    bthread::TaskGroup* g = bthread::tls_task_group;
+    bthread::TaskGroup* g = bthread::BAIDU_GET_VOLATILE_THREAD_LOCAL(tls_task_group);
     if (NULL != g && !g->is_current_pthread_task()) {
         return bthread::TaskGroup::usleep(&g, microseconds);
     }
@@ -529,7 +530,7 @@ int bthread_usleep(uint64_t microseconds) {
 }
 
 int bthread_yield(void) {
-    bthread::TaskGroup* g = bthread::tls_task_group;
+    bthread::TaskGroup* g = bthread::BAIDU_GET_VOLATILE_THREAD_LOCAL(tls_task_group);
     if (NULL != g && !g->is_current_pthread_task()) {
         bthread::TaskGroup::yield(&g);
         return 0;