Merge basic-improvements-branch to trunk

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@60174 138bc75d-0d04-0410-961f-82ee72b054a4
author: zack <zack@138bc75d-0d04-0410-961f-82ee72b054a4> 2002-12-16 18:23:00 +0000
committer: zack <zack@138bc75d-0d04-0410-961f-82ee72b054a4> 2002-12-16 18:23:00 +0000
commit: 805e22b2051e9c6a75377ea6599654d7415da483 (patch)
tree: c259697c448b0c6f548f153c48c46a8d7a75970f /gcc/config/vxlib.c
parent: 2c27ce73ee2229b0871c4ccad2342d8a4be85eff (diff)
download: gcc-805e22b2051e9c6a75377ea6599654d7415da483.tar.gz
1 files changed, 325 insertions, 0 deletions
diff --git a/gcc/config/vxlib.c b/gcc/config/vxlib.c
new file mode 100644
index 00000000000..89e0c3514d9
--- /dev/null
+++ b/gcc/config/vxlib.c
@@ -0,0 +1,325 @@
+/* Copyright (C) 2002 Free Software Foundation, Inc.
+   Contributed by Zack Weinberg <zack@codesourcery.com>
+
+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 2, 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.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.  */
+
+/* Threads compatibility routines for libgcc2 for VxWorks.
+   These are out-of-line routines called from gthr-vxworks.h.  */
+
+/* As a special exception, if you link this library with other files,
+   some of which are compiled with GCC, to produce an executable,
+   this library does not by itself cause the resulting executable
+   to be covered by the GNU General Public License.
+   This exception does not however invalidate any other reasons why
+   the executable file might be covered by the GNU General Public License.  */
+
+#include "tconfig.h"
+#include "tsystem.h"
+#include "gthr.h"
+
+#include <vxWorks.h>
+#include <vxLib.h>
+#include <taskLib.h>
+#include <taskHookLib.h>
+
+/* Init-once operation.
+
+   This would be a clone of the implementation from gthr-solaris.h,
+   except that we have a bootstrap problem - the whole point of this
+   exercise is to prevent double initialization, but if two threads
+   are racing with each other, once->mutex is liable to be initialized
+   by both.  Then each thread will lock its own mutex, and proceed to
+   call the initialization routine.
+
+   So instead we use a bare atomic primitive (vxTas()) to handle
+   mutual exclusion.  Threads losing the race then busy-wait, calling
+   taskDelay() to yield the processor, until the initialization is
+   completed.  Inefficient, but reliable.  */
+
+int
+__gthread_once (__gthread_once_t *guard, void (*func)(void))
+{
+  if (guard->done)
+    return 0;
+
+  while (!vxTas ((void *)&guard->busy))
+    taskDelay (1);
+
+  /* Only one thread at a time gets here.  Check ->done again, then
+     go ahead and call func() if no one has done it yet.  */
+  if (!guard->done)
+    {
+      func ();
+      guard->done = 1;
+    }
+
+  guard->busy = 0;
+  return 0;
+}
+
+/* Thread-specific data.
+
+   We reserve a field in the TCB to point to a dynamically allocated
+   array which is used to store TSD values.  A TSD key is simply an
+   offset in this array.  The exact location of the TCB field is not
+   known to this code nor to vxlib.c -- all access to it indirects
+   through the routines __gthread_get_tsd_data and
+   __gthread_set_tsd_data, which are provided by the VxWorks kernel.
+
+   There is also a global array which records which keys are valid and
+   which have destructors.
+
+   A task delete hook is installed to execute key destructors.  The
+   routines __gthread_enter_tsd_dtor_context and
+   __gthread_leave_tsd_dtor_context, which are also provided by the
+   kernel, ensure that it is safe to call free() on memory allocated
+   by the task being deleted.  (This is a no-op on VxWorks 5, but
+   a major undertaking on AE.)
+
+   Since this interface is used to allocate only a small number of
+   keys, the table size is small and static, which simplifies the
+   code quite a bit.  Revisit this if and when it becomes necessary.  */
+
+#define MAX_KEYS 4
+
+/* This is the structure pointed to by the pointer returned
+   by __gthread_get_tsd_data.  */
+struct tsd_data
+{
+  void *values[MAX_KEYS];
+  unsigned int generation[MAX_KEYS];
+};
+
+
+/* kernel provided routines */
+extern void *__gthread_get_tsd_data (WIND_TCB *tcb);
+extern void __gthread_set_tsd_data (WIND_TCB *tcb, void *data);
+
+extern void __gthread_enter_tsd_dtor_context (WIND_TCB *tcb);
+extern void __gthread_leave_tsd_dtor_context (WIND_TCB *tcb);
+
+typedef void (*fet_callback_t) (WIND_TCB *, unsigned int);
+extern void __gthread_for_all_tasks (fet_callback_t fun, unsigned int number);
+
+/* This is a global structure which records all of the active keys.
+
+   A key is potentially valid (i.e. has been handed out by
+   __gthread_key_create) iff its generation count in this structure is
+   even.  In that case, the matching entry in the dtors array is a
+   routine to be called when a thread terminates with a valid,
+   non-NULL specific value for that key.
+
+   A key is actually valid in a thread T iff the generation count
+   stored in this structure is equal to the generation count stored in
+   T's specific-value structure.  */
+
+typedef void (*tsd_dtor) (void *);
+
+struct tsd_keys
+{
+  tsd_dtor dtor[MAX_KEYS];
+  unsigned int generation[MAX_KEYS];
+};
+
+#define KEY_VALID_P(key) !(tsd_keys.generation[key] & 1)
+
+/* Note: if MAX_KEYS is increased, this initializer must be updated
+   to match.  All the generation counts begin at 1, which means no
+   key is valid.  */
+static struct tsd_keys tsd_keys =
+{
+  { 0, 0, 0, 0 },
+  { 1, 1, 1, 1 }
+};
+
+/* This lock protects the tsd_keys structure.  */
+static __gthread_mutex_t tsd_lock;
+
+static __gthread_once_t tsd_init_guard = __GTHREAD_ONCE_INIT;
+
+/* Internal routines.  */
+
+/* The task TCB has just been deleted.  Call the destructor
+   function for each TSD key that has both a destructor and
+   a non-NULL specific value in this thread.
+
+   This routine does not need to take tsd_lock; the generation
+   count protects us from calling a stale destructor.  It does
+   need to read tsd_keys.dtor[key] atomically.  */
+
+static void
+tsd_delete_hook (WIND_TCB *tcb)
+{
+  struct tsd_data *data = __gthread_get_tsd_data (tcb);
+  __gthread_key_t key;
+
+  if (data)
+    {
+      __gthread_enter_tsd_dtor_context (tcb);
+      for (key = 0; key < MAX_KEYS; key++)
+	{
+	  if (data->generation[key] == tsd_keys.generation[key])
+	    {
+	      tsd_dtor dtor = tsd_keys.dtor[key];
+
+	      if (dtor)
+		dtor (data->values[key]);
+	    }
+	}
+      free (data);
+      __gthread_set_tsd_data (tcb, 0);
+      __gthread_leave_tsd_dtor_context (tcb);
+    }
+} 
+
+/* Initialize global data used by the TSD system.  */
+static void
+tsd_init (void)
+{
+  taskDeleteHookAdd ((FUNCPTR)tsd_delete_hook);
+  __GTHREAD_MUTEX_INIT_FUNCTION (&tsd_lock);
+}
+
+/* External interface */
+
+/* Store in KEYP a value which can be passed to __gthread_setspecific/
+   __gthread_getspecific to store and retrive a value which is
+   specific to each calling thread.  If DTOR is not NULL, it will be
+   called when a thread terminates with a non-NULL specific value for
+   this key, with the value as its sole argument.  */
+
+int
+__gthread_key_create (__gthread_key_t *keyp, tsd_dtor dtor)
+{
+  __gthread_key_t key;
+
+  __gthread_once (&tsd_init_guard, tsd_init);
+
+  if (__gthread_mutex_lock (&tsd_lock) == ERROR)
+    return errno;
+
+  for (key = 0; key < MAX_KEYS; key++)
+    if (!KEY_VALID_P (key))
+      goto found_slot;
+
+  /* no room */
+  __gthread_mutex_unlock (&tsd_lock);
+  return EAGAIN;
+
+ found_slot:
+  tsd_keys.generation[key]++;  /* making it even */
+  tsd_keys.dtor[key] = dtor;
+  *keyp = key;
+  __gthread_mutex_unlock (&tsd_lock);
+  return 0;
+}
+
+/* Invalidate KEY; it can no longer be used as an argument to
+   setspecific/getspecific.  Note that this does NOT call destructor
+   functions for any live values for this key.  */
+int
+__gthread_key_delete (__gthread_key_t key)
+{
+  if (key >= MAX_KEYS)
+    return EINVAL;
+
+  __gthread_once (&tsd_init_guard, tsd_init);
+
+  if (__gthread_mutex_lock (&tsd_lock) == ERROR)
+    return errno;
+
+  if (!KEY_VALID_P (key))
+    {
+      __gthread_mutex_unlock (&tsd_lock);
+      return EINVAL;
+    }
+
+  tsd_keys.generation[key]++;  /* making it odd */
+  tsd_keys.dtor[key] = 0;
+
+  __gthread_mutex_unlock (&tsd_lock);
+  return 0;
+}
+
+/* Retrieve the thread-specific value for KEY.  If it has never been
+   set in this thread, or KEY is invalid, returns NULL.
+
+   It does not matter if this function races with key_create or
+   key_delete; the worst that can happen is you get a value other than
+   the one that a serialized implementation would have provided.  */
+
+void *
+__gthread_getspecific (__gthread_key_t key)
+{
+  struct tsd_data *data;
+
+  if (key >= MAX_KEYS)
+    return 0;
+
+  data = __gthread_get_tsd_data (taskTcb (taskIdSelf ()));
+
+  if (!data)
+    return 0;
+
+  if (data->generation[key] != tsd_keys.generation[key])
+    return 0;
+
+  return data->values[key];
+}
+
+/* Set the thread-specific value for KEY.  If KEY is invalid, or
+   memory allocation fails, returns -1, otherwise 0.
+
+   The generation count protects this function against races with
+   key_create/key_delete; the worst thing that can happen is that a
+   value is successfully stored into a dead generation (and then
+   immediately becomes invalid).  However, we do have to make sure
+   to read tsd_keys.generation[key] atomically.  */
+
+int
+__gthread_setspecific (__gthread_key_t key, void *value)
+{
+  struct tsd_data *data;
+  WIND_TCB *tcb;
+  unsigned int generation;
+
+  if (key >= MAX_KEYS)
+    return EINVAL;
+
+  tcb = taskTcb (taskIdSelf ());
+  data = __gthread_get_tsd_data (tcb);
+  if (!data)
+    {
+      data = malloc (sizeof (struct tsd_data));
+      if (!data)
+	return ENOMEM;
+
+      memset (data, 0, sizeof (struct tsd_data));
+      __gthread_set_tsd_data (tcb, data);
+    }
+
+  generation = tsd_keys.generation[key];
+
+  if (generation & 1)
+    return EINVAL;
+
+  data->generation[key] = generation;
+  data->values[key] = value;
+
+  return 0;
+}
author	zack <zack@138bc75d-0d04-0410-961f-82ee72b054a4>	2002-12-16 18:23:00 +0000
committer	zack <zack@138bc75d-0d04-0410-961f-82ee72b054a4>	2002-12-16 18:23:00 +0000
commit	805e22b2051e9c6a75377ea6599654d7415da483 (patch)
tree	c259697c448b0c6f548f153c48c46a8d7a75970f /gcc/config/vxlib.c
parent	2c27ce73ee2229b0871c4ccad2342d8a4be85eff (diff)
download	gcc-805e22b2051e9c6a75377ea6599654d7415da483.tar.gz