[Mesa-dev] [PATCH v2 03/26] threads: update for late C11 changes

Nicolai Hähnle nhaehnle at gmail.com
Mon Nov 6 10:23:34 UTC 2017


From: Nicolai Hähnle <nicolai.haehnle at amd.com>

C11 threads were changed to use struct timespec instead of xtime, and
thrd_sleep got a second argument.

See http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1554.htm and
http://en.cppreference.com/w/c/thread/{thrd_sleep,cnd_timedwait,mtx_timedlock}

Note that cnd_timedwait is spec'd to be relative to TIME_UTC / CLOCK_REALTIME.

v2: Fix Windows build errors. Tested with a default Appveyor config
    that uses Visual Studio 2013. Judging from Brian's email and
    random internet sources, Visual Studio 2015 does have timespec
    and timespec_get, hence the _MSC_VER-based guard which I have
    not tested.

Cc: Jose Fonseca <jfonseca at vmware.com>
Cc: Brian Paul <brianp at vmware.com>
Reviewed-by: Marek Olšák <marek.olsak at amd.com> (v1)
---
 include/c11/threads.h           | 11 ---------
 include/c11/threads_posix.h     | 39 +++++++++++++-------------------
 include/c11/threads_win32.h     | 50 ++++++++++++++++++++++++++---------------
 src/egl/drivers/dri2/egl_dri2.c | 24 +++++++++++---------
 4 files changed, 60 insertions(+), 64 deletions(-)

diff --git a/include/c11/threads.h b/include/c11/threads.h
index 573348d8091..3c3f23a8ab8 100644
--- a/include/c11/threads.h
+++ b/include/c11/threads.h
@@ -23,42 +23,31 @@
  * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  */
 #ifndef EMULATED_THREADS_H_INCLUDED_
 #define EMULATED_THREADS_H_INCLUDED_
 
 #include <time.h>
-#ifdef _MSC_VER
-#include <thr/xtimec.h>  // for xtime
-#endif
 
 #ifndef TIME_UTC
 #define TIME_UTC 1
 #endif
 
 #include "c99_compat.h" /* for `inline` */
 
 /*---------------------------- types ----------------------------*/
 typedef void (*tss_dtor_t)(void*);
 typedef int (*thrd_start_t)(void*);
 
-#ifndef _MSC_VER
-struct xtime {
-    time_t sec;
-    long nsec;
-};
-typedef struct xtime xtime;
-#endif
-
 
 /*-------------------- enumeration constants --------------------*/
 enum {
     mtx_plain     = 0,
     mtx_try       = 1,
     mtx_timed     = 2,
     mtx_recursive = 4
 };
 
 enum {
diff --git a/include/c11/threads_posix.h b/include/c11/threads_posix.h
index 43e803ee8d1..7bf6a0f6ef6 100644
--- a/include/c11/threads_posix.h
+++ b/include/c11/threads_posix.h
@@ -125,33 +125,29 @@ cnd_init(cnd_t *cond)
 // 7.25.3.4
 static inline int
 cnd_signal(cnd_t *cond)
 {
     assert(cond != NULL);
     return (pthread_cond_signal(cond) == 0) ? thrd_success : thrd_error;
 }
 
 // 7.25.3.5
 static inline int
-cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+cnd_timedwait(cnd_t *cond, mtx_t *mtx, const struct timespec *abs_time)
 {
-    struct timespec abs_time;
     int rt;
 
     assert(mtx != NULL);
     assert(cond != NULL);
-    assert(xt != NULL);
+    assert(abs_time != NULL);
 
-    abs_time.tv_sec = xt->sec;
-    abs_time.tv_nsec = xt->nsec;
-
-    rt = pthread_cond_timedwait(cond, mtx, &abs_time);
+    rt = pthread_cond_timedwait(cond, mtx, abs_time);
     if (rt == ETIMEDOUT)
         return thrd_busy;
     return (rt == 0) ? thrd_success : thrd_error;
 }
 
 // 7.25.3.6
 static inline int
 cnd_wait(cnd_t *cond, mtx_t *mtx)
 {
     assert(mtx != NULL);
@@ -228,38 +224,35 @@ mtx_lock(mtx_t *mtx)
 }
 
 static inline int
 mtx_trylock(mtx_t *mtx);
 
 static inline void
 thrd_yield(void);
 
 // 7.25.4.4
 static inline int
-mtx_timedlock(mtx_t *mtx, const xtime *xt)
+mtx_timedlock(mtx_t *mtx, const struct timespec *ts)
 {
     assert(mtx != NULL);
-    assert(xt != NULL);
+    assert(ts != NULL);
 
     {
 #ifdef EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
-    struct timespec ts;
     int rt;
-    ts.tv_sec = xt->sec;
-    ts.tv_nsec = xt->nsec;
-    rt = pthread_mutex_timedlock(mtx, &ts);
+    rt = pthread_mutex_timedlock(mtx, ts);
     if (rt == 0)
         return thrd_success;
     return (rt == ETIMEDOUT) ? thrd_busy : thrd_error;
 #else
     time_t expire = time(NULL);
-    expire += xt->sec;
+    expire += ts->tv_sec;
     while (mtx_trylock(mtx) != thrd_success) {
         time_t now = time(NULL);
         if (expire < now)
             return thrd_busy;
         // busy loop!
         thrd_yield();
     }
     return thrd_success;
 #endif
     }
@@ -335,27 +328,24 @@ thrd_join(thrd_t thr, int *res)
     void *code;
     if (pthread_join(thr, &code) != 0)
         return thrd_error;
     if (res)
         *res = (int)(intptr_t)code;
     return thrd_success;
 }
 
 // 7.25.5.7
 static inline void
-thrd_sleep(const xtime *xt)
+thrd_sleep(const struct timespec *time_point, struct timespec *remaining)
 {
-    struct timespec req;
-    assert(xt);
-    req.tv_sec = xt->sec;
-    req.tv_nsec = xt->nsec;
-    nanosleep(&req, NULL);
+    assert(time_point != NULL);
+    nanosleep(time_point, remaining);
 }
 
 // 7.25.5.8
 static inline void
 thrd_yield(void)
 {
     sched_yield();
 }
 
 
@@ -385,21 +375,22 @@ tss_get(tss_t key)
 // 7.25.6.4
 static inline int
 tss_set(tss_t key, void *val)
 {
     return (pthread_setspecific(key, val) == 0) ? thrd_success : thrd_error;
 }
 
 
 /*-------------------- 7.25.7 Time functions --------------------*/
 // 7.25.6.1
+#if 0
 static inline int
-xtime_get(xtime *xt, int base)
+timespec_get(struct timespec *ts, int base)
 {
-    if (!xt) return 0;
+    if (!ts) return 0;
     if (base == TIME_UTC) {
-        xt->sec = time(NULL);
-        xt->nsec = 0;
+        clock_gettime(CLOCK_REALTIME, ts);
         return base;
     }
     return 0;
 }
+#endif
diff --git a/include/c11/threads_win32.h b/include/c11/threads_win32.h
index af7df4b9ef5..77d923aaf49 100644
--- a/include/c11/threads_win32.h
+++ b/include/c11/threads_win32.h
@@ -68,20 +68,31 @@ Configuration macro:
 
 // check configuration
 #if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && (_WIN32_WINNT < 0x0600)
 #error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
 #endif
 
 #if defined(EMULATED_THREADS_USE_NATIVE_CV) && (_WIN32_WINNT < 0x0600)
 #error EMULATED_THREADS_USE_NATIVE_CV requires _WIN32_WINNT>=0x0600
 #endif
 
+/* Visual Studio 2015 and later */
+#if _MSC_VER >= 1900
+#define HAVE_TIMESPEC
+#endif
+
+#ifndef HAVE_TIMESPEC
+struct timespec {
+    time_t tv_sec;
+    long tv_nsec;
+};
+#endif
 
 /*---------------------------- macros ----------------------------*/
 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 #define ONCE_FLAG_INIT INIT_ONCE_STATIC_INIT
 #else
 #define ONCE_FLAG_INIT {0}
 #endif
 #define TSS_DTOR_ITERATIONS 1
 
 // FIXME: temporary non-standard hack to ease transition
@@ -139,23 +150,23 @@ static unsigned __stdcall impl_thrd_routine(void *p)
 {
     struct impl_thrd_param pack;
     int code;
     memcpy(&pack, p, sizeof(struct impl_thrd_param));
     free(p);
     code = pack.func(pack.arg);
     impl_tss_dtor_invoke();
     return (unsigned)code;
 }
 
-static DWORD impl_xtime2msec(const xtime *xt)
+static DWORD impl_timespec2msec(const struct timespec *ts)
 {
-    return (DWORD)((xt->sec * 1000U) + (xt->nsec / 1000000L));
+    return (DWORD)((ts->tv_sec * 1000U) + (ts->tv_nsec / 1000000L));
 }
 
 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 struct impl_call_once_param { void (*func)(void); };
 static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce, PVOID Parameter, PVOID *Context)
 {
     struct impl_call_once_param *param = (struct impl_call_once_param*)Parameter;
     (param->func)();
     ((void)InitOnce); ((void)Context);  // suppress warning
     return TRUE;
@@ -199,34 +210,34 @@ static void impl_cond_do_signal(cnd_t *cond, int broadcast)
             nsignal = cond->to_unblock = 1;
             cond->blocked--;
         }
     }
     LeaveCriticalSection(&cond->monitor);
 
     if (0 < nsignal)
         ReleaseSemaphore(cond->sem_queue, nsignal, NULL);
 }
 
-static int impl_cond_do_wait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+static int impl_cond_do_wait(cnd_t *cond, mtx_t *mtx, const struct timespec *ts)
 {
     int nleft = 0;
     int ngone = 0;
     int timeout = 0;
     DWORD w;
 
     WaitForSingleObject(cond->sem_gate, INFINITE);
     cond->blocked++;
     ReleaseSemaphore(cond->sem_gate, 1, NULL);
 
     mtx_unlock(mtx);
 
-    w = WaitForSingleObject(cond->sem_queue, xt ? impl_xtime2msec(xt) : INFINITE);
+    w = WaitForSingleObject(cond->sem_queue, ts ? impl_timespec2msec(ts) : INFINITE);
     timeout = (w == WAIT_TIMEOUT);
  
     EnterCriticalSection(&cond->monitor);
     if ((nleft = cond->to_unblock) != 0) {
         if (timeout) {
             if (cond->blocked != 0) {
                 cond->blocked--;
             } else {
                 cond->gone++;
             }
@@ -371,29 +382,29 @@ cnd_signal(cnd_t *cond)
 #ifdef EMULATED_THREADS_USE_NATIVE_CV
     WakeConditionVariable(&cond->condvar);
 #else
     impl_cond_do_signal(cond, 0);
 #endif
     return thrd_success;
 }
 
 // 7.25.3.5
 static inline int
-cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+cnd_timedwait(cnd_t *cond, mtx_t *mtx, const struct timespec *abs_time)
 {
-    if (!cond || !mtx || !xt) return thrd_error;
+    if (!cond || !mtx || !abs_time) return thrd_error;
 #ifdef EMULATED_THREADS_USE_NATIVE_CV
-    if (SleepConditionVariableCS(&cond->condvar, mtx, impl_xtime2msec(xt)))
+    if (SleepConditionVariableCS(&cond->condvar, mtx, impl_timespec2msec(abs_time)))
         return thrd_success;
     return (GetLastError() == ERROR_TIMEOUT) ? thrd_busy : thrd_error;
 #else
-    return impl_cond_do_wait(cond, mtx, xt);
+    return impl_cond_do_wait(cond, mtx, abs_time);
 #endif
 }
 
 // 7.25.3.6
 static inline int
 cnd_wait(cnd_t *cond, mtx_t *mtx)
 {
     if (!cond || !mtx) return thrd_error;
 #ifdef EMULATED_THREADS_USE_NATIVE_CV
     SleepConditionVariableCS(&cond->condvar, mtx, INFINITE);
@@ -431,26 +442,26 @@ mtx_init(mtx_t *mtx, int type)
 static inline int
 mtx_lock(mtx_t *mtx)
 {
     if (!mtx) return thrd_error;
     EnterCriticalSection(mtx);
     return thrd_success;
 }
 
 // 7.25.4.4
 static inline int
-mtx_timedlock(mtx_t *mtx, const xtime *xt)
+mtx_timedlock(mtx_t *mtx, const struct timespec *ts)
 {
     time_t expire, now;
-    if (!mtx || !xt) return thrd_error;
+    if (!mtx || !ts) return thrd_error;
     expire = time(NULL);
-    expire += xt->sec;
+    expire += ts->tv_sec;
     while (mtx_trylock(mtx) != thrd_success) {
         now = time(NULL);
         if (expire < now)
             return thrd_busy;
         // busy loop!
         thrd_yield();
     }
     return thrd_success;
 }
 
@@ -572,24 +583,25 @@ thrd_join(thrd_t thr, int *res)
             return thrd_error;
         }
         *res = (int)code;
     }
     CloseHandle(thr);
     return thrd_success;
 }
 
 // 7.25.5.7
 static inline void
-thrd_sleep(const xtime *xt)
+thrd_sleep(const struct timespec *time_point, struct timespec *remaining)
 {
-    assert(xt);
-    Sleep(impl_xtime2msec(xt));
+    assert(time_point);
+    assert(!remaining); /* not implemented */
+    Sleep(impl_timespec2msec(time_point));
 }
 
 // 7.25.5.8
 static inline void
 thrd_yield(void)
 {
     SwitchToThread();
 }
 
 
@@ -626,21 +638,23 @@ tss_get(tss_t key)
 // 7.25.6.4
 static inline int
 tss_set(tss_t key, void *val)
 {
     return TlsSetValue(key, val) ? thrd_success : thrd_error;
 }
 
 
 /*-------------------- 7.25.7 Time functions --------------------*/
 // 7.25.6.1
+#ifndef HAVE_TIMESPEC
 static inline int
-xtime_get(xtime *xt, int base)
+timespec_get(struct timespec *ts, int base)
 {
-    if (!xt) return 0;
+    if (!ts) return 0;
     if (base == TIME_UTC) {
-        xt->sec = time(NULL);
-        xt->nsec = 0;
+        ts->tv_sec = time(NULL);
+        ts->tv_nsec = 0;
         return base;
     }
     return 0;
 }
+#endif
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 503450542e5..c4771cb45e7 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -3065,24 +3065,20 @@ dri2_dup_native_fence_fd(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSync *sync)
 static EGLint
 dri2_client_wait_sync(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSync *sync,
                       EGLint flags, EGLTime timeout)
 {
    _EGLContext *ctx = _eglGetCurrentContext();
    struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
    struct dri2_egl_context *dri2_ctx = dri2_egl_context(ctx);
    struct dri2_egl_sync *dri2_sync = dri2_egl_sync(sync);
    unsigned wait_flags = 0;
 
-   /* timespecs for cnd_timedwait */
-   struct timespec current;
-   xtime expire;
-
    EGLint ret = EGL_CONDITION_SATISFIED_KHR;
 
    /* The EGL_KHR_fence_sync spec states:
     *
     *    "If no context is current for the bound API,
     *     the EGL_SYNC_FLUSH_COMMANDS_BIT_KHR bit is ignored.
     */
    if (dri2_ctx && flags & EGL_SYNC_FLUSH_COMMANDS_BIT_KHR)
       wait_flags |= __DRI2_FENCE_FLAG_FLUSH_COMMANDS;
 
@@ -3109,33 +3105,39 @@ dri2_client_wait_sync(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSync *sync,
       }
 
       /* if timeout is EGL_FOREVER_KHR, it should wait without any timeout.*/
       if (timeout == EGL_FOREVER_KHR) {
          mtx_lock(&dri2_sync->mutex);
          cnd_wait(&dri2_sync->cond, &dri2_sync->mutex);
          mtx_unlock(&dri2_sync->mutex);
       } else {
          /* if reusable sync has not been yet signaled */
          if (dri2_sync->base.SyncStatus != EGL_SIGNALED_KHR) {
+            /* timespecs for cnd_timedwait */
+            struct timespec current;
+            struct timespec expire;
+
+            /* We override the clock to monotonic when creating the condition
+             * variable. */
             clock_gettime(CLOCK_MONOTONIC, &current);
 
             /* calculating when to expire */
-            expire.nsec = timeout % 1000000000L;
-            expire.sec = timeout / 1000000000L;
+            expire.tv_nsec = timeout % 1000000000L;
+            expire.tv_sec = timeout / 1000000000L;
 
-            expire.nsec += current.tv_nsec;
-            expire.sec += current.tv_sec;
+            expire.tv_nsec += current.tv_nsec;
+            expire.tv_sec += current.tv_sec;
 
             /* expire.nsec now is a number between 0 and 1999999998 */
-            if (expire.nsec > 999999999L) {
-               expire.sec++;
-               expire.nsec -= 1000000000L;
+            if (expire.tv_nsec > 999999999L) {
+               expire.tv_sec++;
+               expire.tv_nsec -= 1000000000L;
             }
 
             mtx_lock(&dri2_sync->mutex);
             ret = cnd_timedwait(&dri2_sync->cond, &dri2_sync->mutex, &expire);
             mtx_unlock(&dri2_sync->mutex);
 
             if (ret == thrd_busy) {
                if (dri2_sync->base.SyncStatus == EGL_UNSIGNALED_KHR) {
                   ret = EGL_TIMEOUT_EXPIRED_KHR;
                } else {
-- 
2.11.0



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