gthr_aux: Unify thread implementation

Reference: #270
Signed-off-by: LIU Hao <lh_mouse@126.com>

mcfgthread/c11.c

@@ -12,16 +12,6 @@
 #include "c11.h"
 #include "clock.h"
 
-__MCF_DLLEXPORT
-void
-__MCF_c11_thread_thunk_v2(_MCF_thread* thrd)
-  {
-    __MCF_c11_thread_record* rec = _MCF_thread_get_data(thrd);
-
-    /* Invoke the user-defined procedure and save its result in the record.  */
-    rec->__result = (*(rec->__proc)) (rec->__arg);
-  }
-
 __MCF_DLLEXPORT
 int
 __MCF_c11_thrd_sleep(const __MCF_timespec* dur, __MCF_timespec* rem_opt)

mcfgthread/c11.h

@@ -56,11 +56,6 @@ typedef _MCF_once once_flag;
 typedef _MCF_cond cnd_t;
 typedef __MCF_c11_mutex mtx_t;
 
-/* This is the actual thread function for a C11 thread.  */
-__MCF_C11_IMPORT
-void
-__MCF_c11_thread_thunk_v2(_MCF_thread* __thrd) __MCF_noexcept;
-
 /* Define enumeration constants.  */
 enum __MCF_mtx_type
   {
@@ -510,16 +505,8 @@ __MCF_C11_INLINE
 int
 __MCF_c11_thrd_create(thrd_t* __thrdp, thrd_start_t __proc, void* __arg) __MCF_noexcept
   {
-    __MCF_c11_thread_record __rec[1] = __MCF_0_INIT;
-    _MCF_thread* __thrd;
-
-    __rec->__proc = __proc;
-    __rec->__arg = __arg;
-    __rec->__joinable[0] = 1;
-
-    __thrd = _MCF_thread_new(__MCF_c11_thread_thunk_v2, __rec, sizeof(*__rec));
-    *__thrdp = __thrd;
-    return (__thrd == __MCF_nullptr) ? thrd_nomem : thrd_success;
+    *__thrdp = __MCF_gthr_thread_create_v3(__MCF_CAST_PTR(__MCF_gthr_thread_procedure, __proc), __arg);
+    return (*__thrdp == __MCF_nullptr) ? thrd_nomem : thrd_success;
   }
 
 __MCF_C11_INLINE __MCF_FN_CONST
@@ -533,15 +520,6 @@ __MCF_C11_INLINE
 int
 __MCF_c11_thrd_detach(thrd_t __thrd) __MCF_noexcept
   {
-    __MCF_c11_thread_record* __rec = __MCF_nullptr;
-    if(__thrd->__proc == __MCF_c11_thread_thunk_v2)
-      __rec = (__MCF_c11_thread_record*) _MCF_thread_get_data(__thrd);
-
-    /* Clear the joinable state. If the thread is not joinable, fail.  */
-    if(__rec && (_MCF_atomic_xchg_8_rlx(__rec->__joinable, 0) == 0))
-      return thrd_error;
-
-    /* Free the thread.  */
     _MCF_thread_drop_ref(__thrd);
     return thrd_success;
   }
@@ -557,37 +535,17 @@ __MCF_C11_INLINE __MCF_NEVER_RETURN
 void
 __MCF_c11_thrd_exit(int __result) __MCF_noexcept
   {
-    _MCF_thread* __self = _MCF_thread_self();
-    int* __resp = __MCF_nullptr;
-    if(__self->__proc == __MCF_c11_thread_thunk_v2)
-      __resp = &(((__MCF_c11_thread_record*) _MCF_thread_get_data(__self))->__result);
-
-    /* Set the exit status and exit. Unlike `ExitThread()`, if the last
-     * thread exits, the current process exits with zero.  */
-    __MCF_SET_IF(__resp, __result);
-    _MCF_thread_exit();
+    __MCF_gthr_thread_exit_v3((void*)(intptr_t) __result);
   }
 
 __MCF_C11_INLINE
 int
 __MCF_c11_thrd_join(thrd_t __thrd, int* __resp_opt) __MCF_noexcept
   {
-    __MCF_c11_thread_record* __rec = __MCF_nullptr;
-    if(__thrd->__proc == __MCF_c11_thread_thunk_v2)
-      __rec = (__MCF_c11_thread_record*) _MCF_thread_get_data(__thrd);
-
-    if(__thrd->__tid == _MCF_thread_self_tid())
-      return thrd_error;
-
-    /* Clear the joinable state. If the thread is not joinable, fail.  */
-    if(__rec && (_MCF_atomic_xchg_8_rlx(__rec->__joinable, 0) == 0))
-      return thrd_error;
-
-    /* Wait for the thread to terminate.  */
-    _MCF_thread_wait(__thrd, __MCF_nullptr);
-    __MCF_SET_IF(__resp_opt, __rec ? __rec->__result : 0);
-    _MCF_thread_drop_ref(__thrd);
-    return 0;
+    void* __resp;
+    __MCF_gthr_thread_join_v3(__thrd, &__resp);
+    __MCF_SET_IF(__resp_opt, (int)(intptr_t) __resp);
+    return thrd_success;
   }
 
 __MCF_C11_INLINE

mcfgthread/gthr.h

@@ -305,31 +305,31 @@ __MCF_FNA(__MCF_gthr_cond_broadcast, __gthread_cond_broadcast);
 /* Creates a thread, like `pthread_create()`.  */
 __MCF_GTHR_IMPORT
 int
-__MCF_gthr_create_v2(__gthread_t* __thrdp, __MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept;
+__MCF_gthr_create_v3(__gthread_t* __thrdp, __MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept;
 
 #ifndef __MCF_GTHR_NO_ALIASES
-__MCF_FNA(__MCF_gthr_create_v2, __gthread_create);
-#  define __MCF_gthr_create_v2  __gthread_create
+__MCF_FNA(__MCF_gthr_create_v3, __gthread_create);
+#  define __MCF_gthr_create_v3  __gthread_create
 #endif
 
 /* Awaits a thread to terminate and gets its result, like `pthread_join()`.  */
 __MCF_GTHR_IMPORT
 int
-__MCF_gthr_join_v2(__gthread_t __thrd, void** __resp_opt) __MCF_noexcept;
+__MCF_gthr_join_v3(__gthread_t __thrd, void** __resp_opt) __MCF_noexcept;
 
 #ifndef __MCF_GTHR_NO_ALIASES
-__MCF_FNA(__MCF_gthr_join_v2, __gthread_join);
-#  define __MCF_gthr_join_v2  __gthread_join
+__MCF_FNA(__MCF_gthr_join_v3, __gthread_join);
+#  define __MCF_gthr_join_v3  __gthread_join
 #endif
 
 /* Detaches a thread, like `pthread_detach()`  */
 __MCF_GTHR_IMPORT
 int
-__MCF_gthr_detach_v2(__gthread_t __thrd) __MCF_noexcept;
+__MCF_gthr_detach(__gthread_t __thrd) __MCF_noexcept;
 
 #ifndef __MCF_GTHR_NO_ALIASES
-__MCF_FNA(__MCF_gthr_detach_v2, __gthread_detach);
-#  define __MCF_gthr_detach_v2  __gthread_detach
+__MCF_FNA(__MCF_gthr_detach, __gthread_detach);
+#  define __MCF_gthr_detach  __gthread_detach
 #endif
 
 /* Gets a thread itself, like `pthread_self()`.
@@ -593,55 +593,24 @@ __MCF_gthr_cond_broadcast(__gthread_cond_t* __cond) __MCF_noexcept
 
 __MCF_GTHR_INLINE
 int
-__MCF_gthr_create_v2(__gthread_t* __thrdp, __MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept
+__MCF_gthr_create_v3(__gthread_t* __thrdp, __MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept
   {
-    __MCF_gthr_thread_record __rec[1] = __MCF_0_INIT;
-    _MCF_thread* __thrd;
-
-    __rec->__proc = __proc;
-    __rec->__arg = __arg;
-    __rec->__joinable[0] = 1;
-
-    __thrd = _MCF_thread_new(__MCF_gthr_thread_thunk_v2, __rec, sizeof(*__rec));
-    *__thrdp = __thrd;
-    return (__thrd == __MCF_nullptr) ? EAGAIN : 0;
+    *__thrdp = __MCF_gthr_thread_create_v3(__proc, __arg);
+    return (*__thrdp == __MCF_nullptr) ? EAGAIN : 0;
   }
 
 __MCF_GTHR_INLINE
 int
-__MCF_gthr_join_v2(__gthread_t __thrd, void** __resp_opt) __MCF_noexcept
+__MCF_gthr_join_v3(__gthread_t __thrd, void** __resp_opt) __MCF_noexcept
   {
-    __MCF_gthr_thread_record* __rec = __MCF_nullptr;
-    if(__thrd->__proc == __MCF_gthr_thread_thunk_v2)
-      __rec = (__MCF_gthr_thread_record*) _MCF_thread_get_data(__thrd);
-
-    if(__thrd->__tid == _MCF_thread_self_tid())
-      return EDEADLK;
-
-    /* Clear the joinable state. If the thread is not joinable, fail.  */
-    if(__rec && (_MCF_atomic_xchg_8_rlx(__rec->__joinable, 0) == 0))
-      return EINVAL;
-
-    /* Wait for the thread to terminate.  */
-    _MCF_thread_wait(__thrd, __MCF_nullptr);
-    __MCF_SET_IF(__resp_opt, __rec ? __rec->__result : __MCF_nullptr);
-    _MCF_thread_drop_ref(__thrd);
+    __MCF_gthr_thread_join_v3(__thrd, __resp_opt);
     return 0;
   }
 
 __MCF_GTHR_INLINE
 int
-__MCF_gthr_detach_v2(__gthread_t __thrd) __MCF_noexcept
+__MCF_gthr_detach(__gthread_t __thrd) __MCF_noexcept
   {
-    __MCF_gthr_thread_record* __rec = __MCF_nullptr;
-    if(__thrd->__proc == __MCF_gthr_thread_thunk_v2)
-      __rec = (__MCF_gthr_thread_record*) _MCF_thread_get_data(__thrd);
-
-    /* Clear the joinable state. If the thread is not joinable, fail.  */
-    if(__rec && (_MCF_atomic_xchg_8_rlx(__rec->__joinable, 0) == 0))
-      return EINVAL;
-
-    /* Free the thread.  */
     _MCF_thread_drop_ref(__thrd);
     return 0;
   }

mcfgthread/gthr_aux.c

@@ -301,12 +301,76 @@ __MCF_gthr_cond_recursive_mutex_wait(_MCF_cond* cond, __MCF_gthr_rc_mutex* rmtx,
                           (intptr_t) rmtx, timeout_opt);
   }
 
-__MCF_DLLEXPORT
+static __MCF_ALIGNED(16)
+const GUID gthread_guid = __MCF_GUID(9FB2D15C,C5F2,4AE7,868D,2769591B8E92);
+
+static
 void
-__MCF_gthr_thread_thunk_v2(_MCF_thread* thrd)
+do_gthr_thread_thunk_v3(_MCF_thread* thrd)
   {
     __MCF_gthr_thread_record* rec = _MCF_thread_get_data(thrd);
+    rec->__arg_or_result = (*(rec->__proc)) (rec->__arg_or_result);
+  }
+
+static inline
+__MCF_gthr_thread_record*
+do_gthr_get_thread_record(_MCF_thread* thrd)
+  {
+    __MCF_gthr_thread_record* rec = _MCF_thread_get_data(thrd);
+    if(!rec)
+      return __MCF_nullptr;
+
+    /* Check the GUID. As user-defined data are aligned to 16-byte boundaries,
+     * there must be at least 16 bytes available.  */
+    if(__builtin_memcmp(rec->__magic_guid, &gthread_guid, 16) != 0)
+      return __MCF_nullptr;
+
+    /* Assume so. `do_gthr_thread_thunk_v3()` is not shared across modules,
+     * so we should not check it for uniqueness.  */
+    return rec;
+  }
+
+__MCF_DLLEXPORT
+_MCF_thread*
+__MCF_gthr_thread_create_v3(__MCF_gthr_thread_procedure* proc, void* arg)
+  {
+    __MCF_ALIGNED(16) __MCF_gthr_thread_record record;
+    __builtin_memcpy(record.__magic_guid, &gthread_guid, 16);
+    record.__proc = proc;
+    record.__arg_or_result = arg;
+    return _MCF_thread_new(do_gthr_thread_thunk_v3, &record, sizeof(record));
+  }
+
+__MCF_DLLEXPORT
+void
+__MCF_gthr_thread_join_v3(_MCF_thread* thrd, void** resp_opt)
+  {
+    /* Wait for the thread to terminate.  */
+    __MCF_ASSERT(thrd->__tid != _MCF_thread_self_tid());
+    _MCF_thread_wait(thrd, __MCF_nullptr);
+
+    if(resp_opt) {
+      *resp_opt = __MCF_nullptr;
+
+      /* Get the exit code.  */
+      __MCF_gthr_thread_record* rec = do_gthr_get_thread_record(thrd);
+      if(rec)
+        *resp_opt = rec->__arg_or_result;
+    }
+
+    /* Free the thread.  */
+    _MCF_thread_drop_ref(thrd);
+  }
+
+__MCF_DLLEXPORT
+void
+__MCF_gthr_thread_exit_v3(void* resp)
+  {
+    /* Set the exit code.  */
+    __MCF_gthr_thread_record* rec = do_gthr_get_thread_record(_MCF_thread_self());
+    if(rec)
+      rec->__arg_or_result = resp;
 
-    /* Invoke the user-defined procedure and save its result in the record.  */
-    rec->__result = (*(rec->__proc)) (rec->__arg);
+    /* Terminate the current thread.  */
+    _MCF_thread_exit();
   }

mcfgthread/gthr_aux.h

@@ -36,12 +36,9 @@ struct __MCF_gthr_rc_mutex
 
 struct __MCF_gthr_thread_record
   {
-    void* __result;
+    uint8_t __magic_guid[16];
     __MCF_gthr_thread_procedure* __proc;
-    void* __arg;
-    uint8_t __joinable[1];
-    uintptr_t __reserved_low;
-    uintptr_t __reserved_high;
+    void* __arg_or_result;
   };
 
 /* These functions implement `__gthread_once()`. If `__once_fn` initiates stack
@@ -135,10 +132,18 @@ __MCF_GTHR_AUX_IMPORT
 int
 __MCF_gthr_cond_recursive_mutex_wait(_MCF_cond* __cond, __MCF_gthr_rc_mutex* __rmtx, int64_t* __timeout_opt) __MCF_noexcept;
 
-/* This is the actual thread function for a gthread.  */
+/* These are auxiliary functions for threads.  */
 __MCF_GTHR_AUX_IMPORT
+_MCF_thread*
+__MCF_gthr_thread_create_v3(__MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept;
+
+__MCF_GTHR_AUX_IMPORT
+void
+__MCF_gthr_thread_join_v3(_MCF_thread* __thrd, void** __resp_opt) __MCF_noexcept;
+
+__MCF_GTHR_AUX_IMPORT __MCF_NEVER_RETURN
 void
-__MCF_gthr_thread_thunk_v2(_MCF_thread* __thrd) __MCF_noexcept;
+__MCF_gthr_thread_exit_v3(void* __resp) __MCF_noexcept;
 
 /* Define inline functions after all declarations.
  * We would like to keep them away from declarations for conciseness, which also

mcfgthread/gthr_libobjc.h

@@ -352,19 +352,14 @@ __MCF_GTHR_LIBOBJC_INLINE
 objc_thread_t
 __MCF_gthr_objc_thread_detach(__MCF_gthr_thread_procedure* __proc, void* __arg) __MCF_noexcept
   {
-    __MCF_gthr_thread_record __rec[1] = __MCF_0_INIT;
-    _MCF_thread* __thrd;
-    uint32_t __tid;
-
-    __rec->__proc = __proc;
-    __rec->__arg = __arg;
-
-    __thrd = _MCF_thread_new(__MCF_gthr_thread_thunk_v2, __rec, sizeof(*__rec));
+    uint32_t __tid = 0;
+    _MCF_thread* __thrd = __MCF_gthr_thread_create_v3(__proc, __arg);
     if(!__thrd)
       return __MCF_nullptr;
 
     __tid = __thrd->__tid;
     _MCF_thread_drop_ref_nonnull(__thrd);
+
     return (objc_thread_t)(uintptr_t) __tid;
   }