New options --enable-threads=isoc and --enable-threads=isoc+posix.

* m4/threadlib.m4 (gl_THREADLIB_EARLY_BODY): Accept the options
--enable-threads=isoc and --enable-threads=isoc+posix.
(gl_THREADLIB_BODY): Test whether the ISO C threads API is available.
When both the ISO C and the POSIX threads API are available, choose
USE_ISOC_AND_POSIX_THREADS instead of USE_POSIX_THREADS if
--enable-threads=isoc+posix was specified. When only the ISO C threads
API is available and --enable-threads=iso was specified, choose
USE_ISOC_THREADS.
* lib/glthread/lock.h: Add new code for USE_ISOC_THREADS ||
USE_ISOC_AND_POSIX_THREADS.
* lib/glthread/lock.c: Likewise.
* lib/glthread/cond.h: Likewise.
* lib/glthread/cond.c: Likewise.
* lib/glthread/tls.h: Likewise.
* lib/glthread/tls.c: Likewise.
* lib/glthread/yield.h: Likewise.
* lib/glthread/thread.h: Add new code for USE_ISOC_THREADS. Treat
USE_ISOC_AND_POSIX_THREADS like USE_POSIX_THREADS.
* lib/glthread/thread.c: Likewise.
* lib/glthread/threadlib.c: Likewise.
* tests/test-lock.c: Save and restore the values of USE_ISOC_THREADS and
USE_ISOC_AND_POSIX_THREADS.
* tests/test-cond.c: Consider USE_ISOC_THREADS and
USE_ISOC_AND_POSIX_THREADS.
* tests/test-tls.c: Likewise.
* tests/test-thread_create.c (main): Likewise.
* tests/test-pthread-cond.c: Likewise.
* tests/test-pthread-mutex.c: Likewise.
* tests/test-pthread-once2.c: Likewise.
* tests/test-pthread-rwlock.c: Likewise.
* tests/test-pthread-tss.c: Likewise.
* tests/test-pthread_sigmask2.c: Treat USE_ISOC_AND_POSIX_THREADS like
USE_POSIX_THREADS.

1 files changed, 157 insertions, 1 deletions

diff --git a/lib/glthread/thread.c b/lib/glthread/thread.c
index 776bfb6bf4..18e7b237d6 100644
--- a/lib/glthread/thread.c
+++ b/lib/glthread/thread.c
@@ -28,7 +28,163 @@
 
 /* ========================================================================= */
 
-#if USE_POSIX_THREADS
+#if USE_ISOC_THREADS
+
+struct thrd_with_exitvalue
+{
+  thrd_t volatile tid;
+  void * volatile exitvalue;
+};
+
+/* The Thread-Specific Storage (TSS) key that allows to access each thread's
+   'struct thrd_with_exitvalue *' pointer.  */
+static tss_t thrd_with_exitvalue_key;
+
+/* Initializes thrd_with_exitvalue_key.
+   This function must only be called once.  */
+static void
+do_init_thrd_with_exitvalue_key (void)
+{
+  if (tss_create (&thrd_with_exitvalue_key, NULL) != thrd_success)
+    abort ();
+}
+
+/* Initializes thrd_with_exitvalue_key.  */
+static void
+init_thrd_with_exitvalue_key (void)
+{
+  static once_flag once = ONCE_FLAG_INIT;
+  call_once (&once, do_init_thrd_with_exitvalue_key);
+}
+
+typedef union
+        {
+          struct thrd_with_exitvalue t;
+          struct
+          {
+            thrd_t tid; /* reserve memory for t.tid */
+            void *(*mainfunc) (void *);
+            void *arg;
+          } a;
+        }
+        main_arg_t;
+
+static int
+thrd_main_func (void *pmarg)
+{
+  /* Unpack the object that combines mainfunc and arg.  */
+  main_arg_t *main_arg = (main_arg_t *) pmarg;
+  void *(*mainfunc) (void *) = main_arg->a.mainfunc;
+  void *arg = main_arg->a.arg;
+
+  if (tss_set (thrd_with_exitvalue_key, &main_arg->t) != thrd_success)
+    abort ();
+
+  /* Execute mainfunc, with arg as argument.  */
+  {
+    void *exitvalue = mainfunc (arg);
+    /* Store the exitvalue, for use by glthread_join().  */
+    main_arg->t.exitvalue = exitvalue;
+    return 0;
+  }
+}
+
+int
+glthread_create (gl_thread_t *threadp, void *(*mainfunc) (void *), void *arg)
+{
+  init_thrd_with_exitvalue_key ();
+  {
+    /* Combine mainfunc and arg in a single object.
+       A stack-allocated object does not work, because it would be out of
+       existence when thrd_create returns before thrd_main_func is
+       entered.  So, allocate it in the heap.  */
+    main_arg_t *main_arg = (main_arg_t *) malloc (sizeof (main_arg_t));
+    if (main_arg == NULL)
+      return ENOMEM;
+    main_arg->a.mainfunc = mainfunc;
+    main_arg->a.arg = arg;
+    switch (thrd_create ((thrd_t *) &main_arg->t.tid, thrd_main_func, main_arg))
+      {
+      case thrd_success:
+        break;
+      case thrd_nomem:
+        free (main_arg);
+        return ENOMEM;
+      default:
+        free (main_arg);
+        return EAGAIN;
+      }
+    *threadp = &main_arg->t;
+    return 0;
+  }
+}
+
+gl_thread_t
+gl_thread_self (void)
+{
+  init_thrd_with_exitvalue_key ();
+  {
+    gl_thread_t thread =
+      (struct thrd_with_exitvalue *) tss_get (thrd_with_exitvalue_key);
+    if (thread == NULL)
+      {
+        /* This happens only in threads that have not been created through
+           glthread_create(), such as the main thread.  */
+        for (;;)
+          {
+            thread =
+              (struct thrd_with_exitvalue *)
+              malloc (sizeof (struct thrd_with_exitvalue));
+            if (thread != NULL)
+              break;
+            /* Memory allocation failed.  There is not much we can do.  Have to
+               busy-loop, waiting for the availability of memory.  */
+            {
+              struct timespec ts;
+              ts.tv_sec = 1;
+              ts.tv_nsec = 0;
+              thrd_sleep (&ts, NULL);
+            }
+          }
+        thread->tid = thrd_current ();
+        thread->exitvalue = NULL; /* just to be deterministic */
+        if (tss_set (thrd_with_exitvalue_key, thread) != thrd_success)
+          abort ();
+      }
+    return thread;
+  }
+}
+
+int
+glthread_join (gl_thread_t thread, void **return_value_ptr)
+{
+  /* On Solaris 11.4, thrd_join crashes when the second argument we pass is
+     NULL.  */
+  int dummy;
+
+  if (thread == gl_thread_self ())
+    return EINVAL;
+  if (thrd_join (thread->tid, &dummy) != thrd_success)
+    return EINVAL;
+  if (return_value_ptr != NULL)
+    *return_value_ptr = thread->exitvalue;
+  free (thread);
+  return 0;
+}
+
+_Noreturn void
+gl_thread_exit (void *return_value)
+{
+  gl_thread_t thread = gl_thread_self ();
+  thread->exitvalue = return_value;
+  thrd_exit (0);
+}
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS
 
 #include <pthread.h>