QWaitCondition/Android: remove support for relative time waits

This actually saves two clock_gettime(CLOCK_MONOTONIC) system calls
(albeit to the vDSO): one inside QDeadlineTimer::remainingTimeNSecs() to
calculate the remaining time from the deadline, then one other inside
pthread_cond_timedwait_relative_np() to calculate the deadline from the
timeout, so it can place the FUTEX_WAIT_BITSET system call.

In fact, I can't find __pthread_cond_timedwait_relative() in the Bionic
source any more. The last reference was removed in 2015, when Bionic
started using FUTEX_WAIT_BITSET. So this commit is just removing dead
code in current Android.

Pick-to: 6.5
Change-Id: Ieec322d73c1e40ad95c8fffd174689c4fcff40ae
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 0 insertions, 24 deletions

diff --git a/src/corelib/thread/qwaitcondition_unix.cpp b/src/corelib/thread/qwaitcondition_unix.cpp
index 68fb92a0c8..ec215cfb23 100644
--- a/src/corelib/thread/qwaitcondition_unix.cpp
+++ b/src/corelib/thread/qwaitcondition_unix.cpp
@@ -22,17 +22,6 @@
 
 QT_BEGIN_NAMESPACE
 
-#ifdef Q_OS_ANDROID
-// pthread_condattr_setclock is available only since Android 5.0. On older versions, there's
-// a private function for relative waits (hidden in 5.0).
-// Use weakref so we can determine at runtime whether each of them is present.
-static int local_condattr_setclock(pthread_condattr_t*, clockid_t)
-__attribute__((weakref("pthread_condattr_setclock")));
-
-static int local_cond_timedwait_relative(pthread_cond_t*, pthread_mutex_t *, const timespec *)
-__attribute__((weakref("__pthread_cond_timedwait_relative")));
-#endif
-
 static void report_error(int code, const char *where, const char *what)
 {
     if (code != 0)
@@ -49,13 +38,8 @@ void qt_initialize_pthread_cond(pthread_cond_t *cond, const char *where)
 
     pthread_condattr_init(&condattr);
     auto destroy = qScopeGuard([&] { pthread_condattr_destroy(&condattr); });
-#if defined(Q_OS_ANDROID)
-    if (local_condattr_setclock)
-        local_condattr_setclock(&condattr, CLOCK_MONOTONIC);
-#else
     pthread_condattr_setclock(&condattr, CLOCK_MONOTONIC);
 #endif
-#endif
 
     report_error(pthread_cond_init(cond, attrp), where, "cv init");
 }
@@ -91,14 +75,6 @@ public:
     int wait_relative(QDeadlineTimer deadline)
     {
         timespec ti;
-#ifdef Q_OS_ANDROID
-        if (!local_condattr_setclock && local_cond_timedwait_relative) {
-            qint64 nsec = deadline.remainingTimeNSecs();
-            ti.tv_sec = nsec / (1000 * 1000 * 1000);
-            ti.tv_nsec = nsec - ti.tv_sec * 1000 * 1000 * 1000;
-            return local_cond_timedwait_relative(&cond, &mutex, &ti);
-        }
-#endif
         qt_abstime_for_timeout(&ti, deadline);
         return pthread_cond_timedwait(&cond, &mutex, &ti);
     }