gthr-posix95.h

/* Threads compatibility routines for libgcc2 and libobjc.  */
/* Compile this one with gcc.  */
/* Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010
   Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#ifndef GCC_GTHR_POSIX_H
#define GCC_GTHR_POSIX_H

/* POSIX threads specific definitions.
   Easy, since the interface is just one-to-one mapping.  */

#define __GTHREADS 1

/* Some implementations of <pthread.h> require this to be defined.  */
#ifndef _REENTRANT
#define _REENTRANT 1
#endif

#include <pthread.h>
#include <unistd.h>

typedef pthread_key_t __gthread_key_t;
typedef pthread_once_t __gthread_once_t;
typedef pthread_mutex_t __gthread_mutex_t;
typedef pthread_cond_t __gthread_cond_t;

/* POSIX like conditional variables are supported.  Please look at comments
   in gthr.h for details. */
#define __GTHREAD_HAS_COND	1

typedef struct {
  long depth;
  pthread_t owner;
  pthread_mutex_t actual;
} __gthread_recursive_mutex_t;

#define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
#define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
#define __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION __gthread_recursive_mutex_init_function
#define __GTHREAD_COND_INIT PTHREAD_COND_INITIALIZER

#if SUPPORTS_WEAK && GTHREAD_USE_WEAK
# define __gthrw(name) \
  static __typeof(name) __gthrw_ ## name __attribute__ ((__weakref__(#name)));
# define __gthrw_(name) __gthrw_ ## name
#else
# define __gthrw(name)
# define __gthrw_(name) name
#endif

__gthrw(pthread_once)
__gthrw(pthread_key_create)
__gthrw(pthread_key_delete)
__gthrw(pthread_getspecific)
__gthrw(pthread_setspecific)
__gthrw(pthread_create)
__gthrw(pthread_cancel)
__gthrw(pthread_self)

__gthrw(pthread_mutex_init)
__gthrw(pthread_mutex_destroy)
__gthrw(pthread_mutex_lock)
__gthrw(pthread_mutex_trylock)
__gthrw(pthread_mutex_unlock)
__gthrw(pthread_mutexattr_init)
__gthrw(pthread_mutexattr_destroy)

__gthrw(pthread_cond_broadcast)
__gthrw(pthread_cond_wait)

#if defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)
/* Objective-C.  */
__gthrw(pthread_cond_destroy)
__gthrw(pthread_cond_init)
__gthrw(pthread_cond_signal)
__gthrw(pthread_exit)
#ifdef _POSIX_PRIORITY_SCHEDULING
#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
__gthrw(sched_get_priority_max)
__gthrw(sched_get_priority_min)
#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
#endif /* _POSIX_PRIORITY_SCHEDULING */
__gthrw(sched_yield)
__gthrw(pthread_attr_destroy)
__gthrw(pthread_attr_init)
__gthrw(pthread_attr_setdetachstate)
#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
__gthrw(pthread_getschedparam)
__gthrw(pthread_setschedparam)
#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
#endif /* _LIBOBJC || _LIBOBJC_WEAK */

#if SUPPORTS_WEAK && GTHREAD_USE_WEAK

/* On Solaris 2.6 up to 9, the libc exposes a POSIX threads interface even if
   -pthreads is not specified.  The functions are dummies and most return an
   error value.  However pthread_once returns 0 without invoking the routine
   it is passed so we cannot pretend that the interface is active if -pthreads
   is not specified.  On Solaris 2.5.1, the interface is not exposed at all so
   we need to play the usual game with weak symbols.  On Solaris 10 and up, a
   working interface is always exposed.  On FreeBSD 6 and later, libc also
   exposes a dummy POSIX threads interface, similar to what Solaris 2.6 up
   to 9 does.  FreeBSD >= 700014 even provides a pthread_cancel stub in libc,
   which means the alternate __gthread_active_p below cannot be used there.  */

#if defined(__FreeBSD__) || (defined(__sun) && defined(__svr4__))

static volatile int __gthread_active = -1;

static void
__gthread_trigger (void)
{
  __gthread_active = 1;
}

static inline int
__gthread_active_p (void)
{
  static pthread_mutex_t __gthread_active_mutex = PTHREAD_MUTEX_INITIALIZER;
  static pthread_once_t __gthread_active_once = PTHREAD_ONCE_INIT;

  /* Avoid reading __gthread_active twice on the main code path.  */
  int __gthread_active_latest_value = __gthread_active;

  /* This test is not protected to avoid taking a lock on the main code
     path so every update of __gthread_active in a threaded program must
     be atomic with regard to the result of the test.  */
  if (__builtin_expect (__gthread_active_latest_value < 0, 0))
    {
      if (__gthrw_(pthread_once))
	{
	  /* If this really is a threaded program, then we must ensure that
	     __gthread_active has been set to 1 before exiting this block.  */
	  __gthrw_(pthread_mutex_lock) (&__gthread_active_mutex);
	  __gthrw_(pthread_once) (&__gthread_active_once, __gthread_trigger);
	  __gthrw_(pthread_mutex_unlock) (&__gthread_active_mutex);
	}

      /* Make sure we'll never enter this block again.  */
      if (__gthread_active < 0)
	__gthread_active = 0;

      __gthread_active_latest_value = __gthread_active;
    }

  return __gthread_active_latest_value != 0;
}

#else /* neither FreeBSD nor Solaris */

static inline int
__gthread_active_p (void)
{
  static void *const __gthread_active_ptr
    = __extension__ (void *) &__gthrw_(pthread_cancel);
  return __gthread_active_ptr != 0;
}

#endif /* FreeBSD or Solaris */

#else /* not SUPPORTS_WEAK */

/* Similar to Solaris, HP-UX 11 for PA-RISC provides stubs for pthread
   calls in shared flavors of the HP-UX C library.  Most of the stubs
   have no functionality.  The details are described in the "libc cumulative
   patch" for each subversion of HP-UX 11.  There are two special interfaces
   provided for checking whether an application is linked to a shared pthread
   library or not.  However, these interfaces aren't available in early
   pthread libraries.  We also need a test that works for archive
   libraries.  We can't use pthread_once as some libc versions call the
   init function.  We also can't use pthread_create or pthread_attr_init
   as these create a thread and thereby prevent changing the default stack
   size.  The function pthread_default_stacksize_np is available in both
   the archive and shared versions of libpthread.   It can be used to
   determine the default pthread stack size.  There is a stub in some
   shared libc versions which returns a zero size if pthreads are not
   active.  We provide an equivalent stub to handle cases where libc
   doesn't provide one.  */

#if defined(__hppa__) && defined(__hpux__)

static volatile int __gthread_active = -1;

static inline int
__gthread_active_p (void)
{
  /* Avoid reading __gthread_active twice on the main code path.  */
  int __gthread_active_latest_value = __gthread_active;
  size_t __s;

  if (__builtin_expect (__gthread_active_latest_value < 0, 0))
    {
      pthread_default_stacksize_np (0, &__s);
      __gthread_active = __s ? 1 : 0;
      __gthread_active_latest_value = __gthread_active;
    }

  return __gthread_active_latest_value != 0;
}

#else /* not hppa-hpux */

static inline int
__gthread_active_p (void)
{
  return 1;
}

#endif /* hppa-hpux */

#endif /* SUPPORTS_WEAK */

#ifdef _LIBOBJC

/* This is the config.h file in libobjc/ */
#include <config.h>

#ifdef HAVE_SCHED_H
# include <sched.h>
#endif

/* Key structure for maintaining thread specific storage */
static pthread_key_t _objc_thread_storage;
static pthread_attr_t _objc_thread_attribs;

/* Thread local storage for a single thread */
static void *thread_local_storage = NULL;

/* Backend initialization functions */

/* Initialize the threads subsystem.  */
static inline int
__gthread_objc_init_thread_system (void)
{
  if (__gthread_active_p ())
    {
      /* Initialize the thread storage key.  */
      if (__gthrw_(pthread_key_create) (&_objc_thread_storage, NULL) == 0)
	{
	  /* The normal default detach state for threads is
	   * PTHREAD_CREATE_JOINABLE which causes threads to not die
	   * when you think they should.  */
	  if (__gthrw_(pthread_attr_init) (&_objc_thread_attribs) == 0
	      && __gthrw_(pthread_attr_setdetachstate) (&_objc_thread_attribs,
					      PTHREAD_CREATE_DETACHED) == 0)
	    return 0;
	}
    }

  return -1;
}

/* Close the threads subsystem.  */
static inline int
__gthread_objc_close_thread_system (void)
{
  if (__gthread_active_p ()
      && __gthrw_(pthread_key_delete) (_objc_thread_storage) == 0
      && __gthrw_(pthread_attr_destroy) (&_objc_thread_attribs) == 0)
    return 0;

  return -1;
}

/* Backend thread functions */

/* Create a new thread of execution.  */
static inline objc_thread_t
__gthread_objc_thread_detach (void (*func)(void *), void *arg)
{
  objc_thread_t thread_id;
  pthread_t new_thread_handle;

  if (!__gthread_active_p ())
    return NULL;

  if (!(__gthrw_(pthread_create) (&new_thread_handle, &_objc_thread_attribs,
				  (void *) func, arg)))
    thread_id = (objc_thread_t) new_thread_handle;
  else
    thread_id = NULL;

  return thread_id;
}

/* Set the current thread's priority.  */
static inline int
__gthread_objc_thread_set_priority (int priority)
{
  if (!__gthread_active_p ())
    return -1;
  else
    {
#ifdef _POSIX_PRIORITY_SCHEDULING
#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
      pthread_t thread_id = __gthrw_(pthread_self) ();
      int policy;
      struct sched_param params;
      int priority_min, priority_max;

      if (__gthrw_(pthread_getschedparam) (thread_id, &policy, &params) == 0)
	{
	  if ((priority_max = __gthrw_(sched_get_priority_max) (policy)) == -1)
	    return -1;

	  if ((priority_min = __gthrw_(sched_get_priority_min) (policy)) == -1)
	    return -1;

	  if (priority > priority_max)
	    priority = priority_max;
	  else if (priority < priority_min)
	    priority = priority_min;
	  params.sched_priority = priority;

	  /*
	   * The solaris 7 and several other man pages incorrectly state that
	   * this should be a pointer to policy but pthread.h is universally
	   * at odds with this.
	   */
	  if (__gthrw_(pthread_setschedparam) (thread_id, policy, &params) == 0)
	    return 0;
	}
#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
#endif /* _POSIX_PRIORITY_SCHEDULING */
      return -1;
    }
}

/* Return the current thread's priority.  */
static inline int
__gthread_objc_thread_get_priority (void)
{
#ifdef _POSIX_PRIORITY_SCHEDULING
#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
  if (__gthread_active_p ())
    {
      int policy;
      struct sched_param params;

      if (__gthrw_(pthread_getschedparam) (__gthrw_(pthread_self) (), &policy, &params) == 0)
	return params.sched_priority;
      else
	return -1;
    }
  else
#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
#endif /* _POSIX_PRIORITY_SCHEDULING */
    return OBJC_THREAD_INTERACTIVE_PRIORITY;
}

/* Yield our process time to another thread.  */
static inline void
__gthread_objc_thread_yield (void)
{
  if (__gthread_active_p ())
    __gthrw_(sched_yield) ();
}

/* Terminate the current thread.  */
static inline int
__gthread_objc_thread_exit (void)
{
  if (__gthread_active_p ())
    /* exit the thread */
    __gthrw_(pthread_exit) (&__objc_thread_exit_status);

  /* Failed if we reached here */
  return -1;
}

/* Returns an integer value which uniquely describes a thread.  */
static inline objc_thread_t
__gthread_objc_thread_id (void)
{
  if (__gthread_active_p ())
    return (objc_thread_t) __gthrw_(pthread_self) ();
  else
    return (objc_thread_t) 1;
}

/* Sets the thread's local storage pointer.  */
static inline int
__gthread_objc_thread_set_data (void *value)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_setspecific) (_objc_thread_storage, value);
  else
    {
      thread_local_storage = value;
      return 0;
    }
}

/* Returns the thread's local storage pointer.  */
static inline void *
__gthread_objc_thread_get_data (void)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_getspecific) (_objc_thread_storage);
  else
    return thread_local_storage;
}

/* Backend mutex functions */

/* Allocate a mutex.  */
static inline int
__gthread_objc_mutex_allocate (objc_mutex_t mutex)
{
  if (__gthread_active_p ())
    {
      mutex->backend = objc_malloc (sizeof (pthread_mutex_t));

      if (__gthrw_(pthread_mutex_init) ((pthread_mutex_t *) mutex->backend, NULL))
	{
	  objc_free (mutex->backend);
	  mutex->backend = NULL;
	  return -1;
	}
    }

  return 0;
}

/* Deallocate a mutex.  */
static inline int
__gthread_objc_mutex_deallocate (objc_mutex_t mutex)
{
  if (__gthread_active_p ())
    {
      int count;

      /*
       * Posix Threads specifically require that the thread be unlocked
       * for __gthrw_(pthread_mutex_destroy) to work.
       */

      do
	{
	  count = __gthrw_(pthread_mutex_unlock) ((pthread_mutex_t *) mutex->backend);
	  if (count < 0)
	    return -1;
	}
      while (count);

      if (__gthrw_(pthread_mutex_destroy) ((pthread_mutex_t *) mutex->backend))
	return -1;

      objc_free (mutex->backend);
      mutex->backend = NULL;
    }
  return 0;
}

/* Grab a lock on a mutex.  */
static inline int
__gthread_objc_mutex_lock (objc_mutex_t mutex)
{
  if (__gthread_active_p ()
      && __gthrw_(pthread_mutex_lock) ((pthread_mutex_t *) mutex->backend) != 0)
    {
      return -1;
    }

  return 0;
}

/* Try to grab a lock on a mutex.  */
static inline int
__gthread_objc_mutex_trylock (objc_mutex_t mutex)
{
  if (__gthread_active_p ()
      && __gthrw_(pthread_mutex_trylock) ((pthread_mutex_t *) mutex->backend) != 0)
    {
      return -1;
    }

  return 0;
}

/* Unlock the mutex */
static inline int
__gthread_objc_mutex_unlock (objc_mutex_t mutex)
{
  if (__gthread_active_p ()
      && __gthrw_(pthread_mutex_unlock) ((pthread_mutex_t *) mutex->backend) != 0)
    {
      return -1;
    }

  return 0;
}

/* Backend condition mutex functions */

/* Allocate a condition.  */
static inline int
__gthread_objc_condition_allocate (objc_condition_t condition)
{
  if (__gthread_active_p ())
    {
      condition->backend = objc_malloc (sizeof (pthread_cond_t));

      if (__gthrw_(pthread_cond_init) ((pthread_cond_t *) condition->backend, NULL))
	{
	  objc_free (condition->backend);
	  condition->backend = NULL;
	  return -1;
	}
    }

  return 0;
}

/* Deallocate a condition.  */
static inline int
__gthread_objc_condition_deallocate (objc_condition_t condition)
{
  if (__gthread_active_p ())
    {
      if (__gthrw_(pthread_cond_destroy) ((pthread_cond_t *) condition->backend))
	return -1;

      objc_free (condition->backend);
      condition->backend = NULL;
    }
  return 0;
}

/* Wait on the condition */
static inline int
__gthread_objc_condition_wait (objc_condition_t condition, objc_mutex_t mutex)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_cond_wait) ((pthread_cond_t *) condition->backend,
			      (pthread_mutex_t *) mutex->backend);
  else
    return 0;
}

/* Wake up all threads waiting on this condition.  */
static inline int
__gthread_objc_condition_broadcast (objc_condition_t condition)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_cond_broadcast) ((pthread_cond_t *) condition->backend);
  else
    return 0;
}

/* Wake up one thread waiting on this condition.  */
static inline int
__gthread_objc_condition_signal (objc_condition_t condition)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_cond_signal) ((pthread_cond_t *) condition->backend);
  else
    return 0;
}

#else /* _LIBOBJC */

static inline int
__gthread_once (__gthread_once_t *__once, void (*__func) (void))
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_once) (__once, __func);
  else
    return -1;
}

static inline int
__gthread_key_create (__gthread_key_t *__key, void (*__dtor) (void *))
{
  return __gthrw_(pthread_key_create) (__key, __dtor);
}

static inline int
__gthread_key_delete (__gthread_key_t __key)
{
  return __gthrw_(pthread_key_delete) (__key);
}

static inline void *
__gthread_getspecific (__gthread_key_t __key)
{
  return __gthrw_(pthread_getspecific) (__key);
}

static inline int
__gthread_setspecific (__gthread_key_t __key, const void *__ptr)
{
  return __gthrw_(pthread_setspecific) (__key, __ptr);
}

static inline int
__gthread_mutex_destroy (__gthread_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_mutex_destroy) (__mutex);
  else
    return 0;
}

static inline int
__gthread_mutex_lock (__gthread_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_mutex_lock) (__mutex);
  else
    return 0;
}

static inline int
__gthread_mutex_trylock (__gthread_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_mutex_trylock) (__mutex);
  else
    return 0;
}

static inline int
__gthread_mutex_unlock (__gthread_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    return __gthrw_(pthread_mutex_unlock) (__mutex);
  else
    return 0;
}

static inline int
__gthread_recursive_mutex_init_function (__gthread_recursive_mutex_t *__mutex)
{
  __mutex->depth = 0;
  __mutex->owner = (pthread_t) 0;
  return __gthrw_(pthread_mutex_init) (&__mutex->actual, NULL);
}

static inline int
__gthread_recursive_mutex_lock (__gthread_recursive_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    {
      pthread_t __me = __gthrw_(pthread_self) ();

      if (__mutex->owner != __me)
	{
	  __gthrw_(pthread_mutex_lock) (&__mutex->actual);
	  __mutex->owner = __me;
	}

      __mutex->depth++;
    }
  return 0;
}

static inline int
__gthread_recursive_mutex_trylock (__gthread_recursive_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    {
      pthread_t __me = __gthrw_(pthread_self) ();

      if (__mutex->owner != __me)
	{
	  if (__gthrw_(pthread_mutex_trylock) (&__mutex->actual))
	    return 1;
	  __mutex->owner = __me;
	}

      __mutex->depth++;
    }
  return 0;
}

static inline int
__gthread_recursive_mutex_unlock (__gthread_recursive_mutex_t *__mutex)
{
  if (__gthread_active_p ())
    {
      if (--__mutex->depth == 0)
	{
	   __mutex->owner = (pthread_t) 0;
	   __gthrw_(pthread_mutex_unlock) (&__mutex->actual);
	}
    }
  return 0;
}

static inline int
__gthread_cond_broadcast (__gthread_cond_t *__cond)
{
  return __gthrw_(pthread_cond_broadcast) (__cond);
}

static inline int
__gthread_cond_wait (__gthread_cond_t *__cond, __gthread_mutex_t *__mutex)
{
  return __gthrw_(pthread_cond_wait) (__cond, __mutex);
}

static inline int
__gthread_cond_wait_recursive (__gthread_cond_t *__cond,
			       __gthread_recursive_mutex_t *__mutex)
{
  return __gthrw_(pthread_cond_wait) (__cond, &__mutex->actual);
}

#endif /* _LIBOBJC */

#endif /* ! GCC_GTHR_POSIX_H */