From: Jonathan Wakely <jwakely@redhat.com>
Date: Thu, 15 Sep 2022 15:57:30 +0000 (+0100)
Subject: libstdc++: Tweak TSan annotations for std::atomic<shared_ptr<T>>
X-Git-Tag: basepoints/gcc-14~4519
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ecbdfa8b314e2c17da17511b86371f552bffd441;p=thirdparty%2Fgcc.git

libstdc++: Tweak TSan annotations for std::atomic<shared_ptr<T>>

Do not use the __tsan_mutex_not_static flag for annotation functions
where it's not a valid flag.  Also use the try_lock and try_lock_failed
flags to more precisely annotate the CAS loop used to acquire a lock.

libstdc++-v3/ChangeLog:

	* include/bits/shared_ptr_atomic.h (_GLIBCXX_TSAN_MUTEX_PRE_LOCK):
	Replace with ...
	(_GLIBCXX_TSAN_MUTEX_TRY_LOCK): ... this, add try_lock flag.
	(_GLIBCXX_TSAN_MUTEX_TRY_LOCK_FAILED): New macro using
	try_lock_failed flag
	(_GLIBCXX_TSAN_MUTEX_POST_LOCK): Rename to ...
	(_GLIBCXX_TSAN_MUTEX_LOCKED): ... this.
	(_GLIBCXX_TSAN_MUTEX_PRE_UNLOCK): Remove invalid flag.
	(_GLIBCXX_TSAN_MUTEX_POST_UNLOCK): Remove invalid flag.
	(_Sp_atomic::_Atomic_count::lock): Use new macros.
---

diff --git a/libstdc++-v3/include/bits/shared_ptr_atomic.h b/libstdc++-v3/include/bits/shared_ptr_atomic.h
index 4580807f42ca..55d193d4bda7 100644
--- a/libstdc++-v3/include/bits/shared_ptr_atomic.h
+++ b/libstdc++-v3/include/bits/shared_ptr_atomic.h
@@ -32,24 +32,26 @@
 
 #include <bits/atomic_base.h>
 
+// Annotations for the custom locking in atomic<shared_ptr<T>>.
 #if defined _GLIBCXX_TSAN && __has_include(<sanitizer/tsan_interface.h>)
 #include <sanitizer/tsan_interface.h>
 #define _GLIBCXX_TSAN_MUTEX_DESTROY(X) \
   __tsan_mutex_destroy(X, __tsan_mutex_not_static)
-#define _GLIBCXX_TSAN_MUTEX_PRE_LOCK(X) \
-  __tsan_mutex_pre_lock(X, __tsan_mutex_not_static)
-#define _GLIBCXX_TSAN_MUTEX_POST_LOCK(X) \
+#define _GLIBCXX_TSAN_MUTEX_TRY_LOCK(X) \
+  __tsan_mutex_pre_lock(X, __tsan_mutex_not_static|__tsan_mutex_try_lock)
+#define _GLIBCXX_TSAN_MUTEX_TRY_LOCK_FAILED(X) __tsan_mutex_post_lock(X, \
+    __tsan_mutex_not_static|__tsan_mutex_try_lock_failed, 0)
+#define _GLIBCXX_TSAN_MUTEX_LOCKED(X) \
   __tsan_mutex_post_lock(X, __tsan_mutex_not_static, 0)
-#define _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(X) \
-  __tsan_mutex_pre_unlock(X, __tsan_mutex_not_static)
-#define _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(X) \
-  __tsan_mutex_post_unlock(X, __tsan_mutex_not_static)
+#define _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(X) __tsan_mutex_pre_unlock(X, 0)
+#define _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(X) __tsan_mutex_post_unlock(X, 0)
 #define _GLIBCXX_TSAN_MUTEX_PRE_SIGNAL(X) __tsan_mutex_pre_signal(X, 0)
 #define _GLIBCXX_TSAN_MUTEX_POST_SIGNAL(X) __tsan_mutex_post_signal(X, 0)
 #else
 #define _GLIBCXX_TSAN_MUTEX_DESTROY(X)
-#define _GLIBCXX_TSAN_MUTEX_PRE_LOCK(X)
-#define _GLIBCXX_TSAN_MUTEX_POST_LOCK(X)
+#define _GLIBCXX_TSAN_MUTEX_TRY_LOCK(X)
+#define _GLIBCXX_TSAN_MUTEX_TRY_LOCK_FAILED(X)
+#define _GLIBCXX_TSAN_MUTEX_LOCKED(X)
 #define _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(X)
 #define _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(X)
 #define _GLIBCXX_TSAN_MUTEX_PRE_SIGNAL(X)
@@ -431,19 +433,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	      __current = _M_val.load(memory_order_relaxed);
 	    }
 
-	  _GLIBCXX_TSAN_MUTEX_PRE_LOCK(&_M_val);
+	  _GLIBCXX_TSAN_MUTEX_TRY_LOCK(&_M_val);
 
 	  while (!_M_val.compare_exchange_strong(__current,
 						 __current | _S_lock_bit,
 						 __o,
 						 memory_order_relaxed))
 	    {
+	      _GLIBCXX_TSAN_MUTEX_TRY_LOCK_FAILED(&_M_val);
 #if __cpp_lib_atomic_wait
 	      __detail::__thread_relax();
 #endif
 	      __current = __current & ~_S_lock_bit;
+	      _GLIBCXX_TSAN_MUTEX_TRY_LOCK(&_M_val);
 	    }
-	  _GLIBCXX_TSAN_MUTEX_POST_LOCK(&_M_val);
+	  _GLIBCXX_TSAN_MUTEX_LOCKED(&_M_val);
 	  return reinterpret_cast<pointer>(__current);
 	}