[PATCH 1/2] libstdc++: Check _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK with #if [PR121496]

[Jonathan Wakely]

The change in r14-905-g3b7cb33033fbe6 to disable the use of
pthread_mutex_clocklock when TSan is active assumed that the
_GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK macro was always checked with #if
rather than #ifdef, which was not true.

This makes the checks use #if consistently.

libstdc++-v3/ChangeLog:

        PR libstdc++/121496
        * include/std/mutex (__timed_mutex_impl::_M_try_wait_until):
        Change preprocessor condition to use #if instead of #ifdef.
        (recursive_timed_mutex::_M_clocklock): Likewise.
        * testsuite/30_threads/timed_mutex/121496.cc: New test.
---

Tested x86_64-linux.

This needs to be backported to gcc-14 and gcc-15 too.

 libstdc++-v3/include/std/mutex                     |  4 ++--
 .../testsuite/30_threads/timed_mutex/121496.cc     | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc

diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index e575a81c138e..631c38069d4a 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -190,7 +190,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          return static_cast<_Derived*>(this)->_M_timedlock(__ts);
        }
 
-#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
       template<typename _Duration>
        bool
        _M_try_lock_until(const chrono::time_point<chrono::steady_clock,
@@ -377,7 +377,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_timedlock(const __gthread_time_t& __ts)
       { return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); }
 
-#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
       bool
       _M_clocklock(clockid_t __clockid, const __gthread_time_t& __ts)
       { return !pthread_mutex_clocklock(&_M_mutex, __clockid, &__ts); }
diff --git a/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc 
b/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc
new file mode 100644
index 000000000000..d919704b1353
--- /dev/null
+++ b/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc
@@ -0,0 +1,14 @@
+// { dg-do compile { target { { i?86-*-linux* x86_64-*-linux* } && lp64 } } }
+// { dg-require-effective-target c++11 }
+// { dg-options "-fsanitize=thread" }
+
+// PR libstdc++/121496 no member named '_M_clocklock' with -fsanitize=thread
+
+#include <mutex>
+#include <chrono>
+
+void
+test_pr121496(std::timed_mutex& m)
+{
+  (void) m.try_lock_until(std::chrono::steady_clock::time_point{});
+}
-- 
2.50.1