From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: [committed] libstdc++: Add TSan annotations to std::atomic<shared_ptr<T>>
Date: Wed, 14 Sep 2022 23:04:49 +0100 [thread overview]
Message-ID: <20220914220449.276340-1-jwakely@redhat.com> (raw)
Tested powerpc64le-linux, pushed to trunk.
-- >8 --
This adds annotations to std::atomic<shared_ptr<T>> to enable TSan to
understand the custom locking. Without this, TSan reports data races for
accesses to the _M_ptr member, even though those are correctly
synchronized using atomic operations on the tagged pointer.
libstdc++-v3/ChangeLog:
* include/bits/shared_ptr_atomic.h (_GLIBCXX_TSAN_MUTEX_DESTROY)
(_GLIBCXX_TSAN_MUTEX_PRE_LOCK, _GLIBCXX_TSAN_MUTEX_POST_LOCK)
(_GLIBCXX_TSAN_MUTEX_PRE_UNLOCK, _GLIBCXX_TSAN_MUTEX_POST_UNLOCK)
(_GLIBCXX_TSAN_MUTEX_PRE_SIGNAL, _GLIBCXX_TSAN_MUTEX_POST_SIGNAL):
Define macros for TSan annotation functions.
(_Sp_atomic::_Atomic_count): Add annotations.
---
libstdc++-v3/include/bits/shared_ptr_atomic.h | 38 +++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/libstdc++-v3/include/bits/shared_ptr_atomic.h b/libstdc++-v3/include/bits/shared_ptr_atomic.h
index d4bd712fc7d..4580807f42c 100644
--- a/libstdc++-v3/include/bits/shared_ptr_atomic.h
+++ b/libstdc++-v3/include/bits/shared_ptr_atomic.h
@@ -32,6 +32,30 @@
#include <bits/atomic_base.h>
+#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) \
+ __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_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_PRE_UNLOCK(X)
+#define _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(X)
+#define _GLIBCXX_TSAN_MUTEX_PRE_SIGNAL(X)
+#define _GLIBCXX_TSAN_MUTEX_POST_SIGNAL(X)
+#endif
+
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -377,6 +401,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
~_Atomic_count()
{
auto __val = _M_val.load(memory_order_relaxed);
+ _GLIBCXX_TSAN_MUTEX_DESTROY(&_M_val);
__glibcxx_assert(!(__val & _S_lock_bit));
if (auto __pi = reinterpret_cast<pointer>(__val))
{
@@ -406,6 +431,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__current = _M_val.load(memory_order_relaxed);
}
+ _GLIBCXX_TSAN_MUTEX_PRE_LOCK(&_M_val);
+
while (!_M_val.compare_exchange_strong(__current,
__current | _S_lock_bit,
__o,
@@ -416,6 +443,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif
__current = __current & ~_S_lock_bit;
}
+ _GLIBCXX_TSAN_MUTEX_POST_LOCK(&_M_val);
return reinterpret_cast<pointer>(__current);
}
@@ -423,7 +451,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
unlock(memory_order __o) const noexcept
{
+ _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(&_M_val);
_M_val.fetch_sub(1, __o);
+ _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(&_M_val);
}
// Swaps the values of *this and __c, and unlocks *this.
@@ -434,7 +464,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__o != memory_order_seq_cst)
__o = memory_order_release;
auto __x = reinterpret_cast<uintptr_t>(__c._M_pi);
+ _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(&_M_val);
__x = _M_val.exchange(__x, __o);
+ _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(&_M_val);
__c._M_pi = reinterpret_cast<pointer>(__x & ~_S_lock_bit);
}
@@ -443,20 +475,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_M_wait_unlock(memory_order __o) const noexcept
{
+ _GLIBCXX_TSAN_MUTEX_PRE_UNLOCK(&_M_val);
auto __v = _M_val.fetch_sub(1, memory_order_relaxed);
+ _GLIBCXX_TSAN_MUTEX_POST_UNLOCK(&_M_val);
_M_val.wait(__v & ~_S_lock_bit, __o);
}
void
notify_one() noexcept
{
+ _GLIBCXX_TSAN_MUTEX_PRE_SIGNAL(&_M_val);
_M_val.notify_one();
+ _GLIBCXX_TSAN_MUTEX_POST_SIGNAL(&_M_val);
}
void
notify_all() noexcept
{
+ _GLIBCXX_TSAN_MUTEX_PRE_SIGNAL(&_M_val);
_M_val.notify_all();
+ _GLIBCXX_TSAN_MUTEX_POST_SIGNAL(&_M_val);
}
#endif
--
2.37.3
next reply other threads:[~2022-09-14 22:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-14 22:04 Jonathan Wakely [this message]
2022-09-14 22:25 ` Jonathan Wakely
2022-09-14 22:28 ` Jonathan Wakely
2022-09-15 20:46 ` [committed] libstdc++: Tweak TSan annotations for std::atomic<shared_ptr<T>> Jonathan Wakely
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