--- /dev/null
+/* Copyright (C) 2002, 2003, 2004, 2005, 2009 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 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/>. */
+
+/* Threads compatibility routines for libgcc2 for VxWorks.
+ These are out-of-line routines called from gthr-vxworks.h.
+
+ This file provides the TLS related support routines, calling specific
+ VxWorks kernel entry points for this purpose. The base VxWorks 5.x kernels
+ don't feature these entry points, and we provide gthr_supp_vxw_5x.c as an
+ option to fill this gap. Asking users to rebuild a kernel is not to be
+ taken lightly, still, so we have isolated these routines from the rest of
+ vxlib to ensure that the kernel dependencies are only dragged when really
+ necessary. */
+
+#include "tconfig.h"
+#include "tsystem.h"
+#include "gthr.h"
+
+#if defined(__GTHREADS)
+#include <vxWorks.h>
+#ifndef __RTP__
+#include <vxLib.h>
+#endif
+#include <taskLib.h>
+#ifndef __RTP__
+#include <taskHookLib.h>
+#else
+# include <errno.h>
+#endif
+
+/* Thread-local storage.
+
+ We reserve a field in the TCB to point to a dynamically allocated
+ array which is used to store TLS values. A TLS 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_tls_data and
+ __gthread_set_tls_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_tls_dtor_context and
+ __gthread_leave_tls_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.)
+
+ The task delete hook is only installed when at least one thread
+ has TLS data. This is a necessary precaution, to allow this module
+ to be unloaded - a module with a hook can not be removed.
+
+ 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_tls_data. */
+struct tls_data
+{
+ int *owner;
+ void *values[MAX_KEYS];
+ unsigned int generation[MAX_KEYS];
+};
+
+/* To make sure we only delete TLS data associated with this object,
+ include a pointer to a local variable in the TLS data object. */
+static int self_owner;
+
+/* The number of threads for this module which have active TLS data.
+ This is protected by tls_lock. */
+static int active_tls_threads;
+
+/* kernel provided routines */
+extern void *__gthread_get_tls_data (void);
+extern void __gthread_set_tls_data (void *data);
+
+extern void __gthread_enter_tls_dtor_context (void);
+extern void __gthread_leave_tls_dtor_context (void);
+
+
+/* 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 (*tls_dtor) (void *);
+
+struct tls_keys
+{
+ tls_dtor dtor[MAX_KEYS];
+ unsigned int generation[MAX_KEYS];
+};
+
+#define KEY_VALID_P(key) !(tls_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 tls_keys tls_keys =
+{
+ { 0, 0, 0, 0 },
+ { 1, 1, 1, 1 }
+};
+
+/* This lock protects the tls_keys structure. */
+static __gthread_mutex_t tls_lock;
+
+static __gthread_once_t tls_init_guard = __GTHREAD_ONCE_INIT;
+
+/* Internal routines. */
+
+/* The task TCB has just been deleted. Call the destructor
+ function for each TLS key that has both a destructor and
+ a non-NULL specific value in this thread.
+
+ This routine does not need to take tls_lock; the generation
+ count protects us from calling a stale destructor. It does
+ need to read tls_keys.dtor[key] atomically. */
+
+static void
+tls_delete_hook (void *tcb ATTRIBUTE_UNUSED)
+{
+ struct tls_data *data;
+ __gthread_key_t key;
+
+#ifdef __RTP__
+ data = __gthread_get_tls_data ();
+#else
+ /* In kernel mode, we can be called in the context of the thread
+ doing the killing, so must use the TCB to determine the data of
+ the thread being killed. */
+ data = __gthread_get_tsd_data (tcb);
+#endif
+
+ if (data && data->owner == &self_owner)
+ {
+ __gthread_enter_tls_dtor_context ();
+ for (key = 0; key < MAX_KEYS; key++)
+ {
+ if (data->generation[key] == tls_keys.generation[key])
+ {
+ tls_dtor dtor = tls_keys.dtor[key];
+
+ if (dtor)
+ dtor (data->values[key]);
+ }
+ }
+ free (data);
+
+ /* We can't handle an error here, so just leave the thread
+ marked as loaded if one occurs. */
+ if (__gthread_mutex_lock (&tls_lock) != ERROR)
+ {
+ active_tls_threads--;
+ if (active_tls_threads == 0)
+ taskDeleteHookDelete ((FUNCPTR)tls_delete_hook);
+ __gthread_mutex_unlock (&tls_lock);
+ }
+#ifdef __RTP__
+ __gthread_set_tls_data (0);
+#else
+ __gthread_set_tsd_data (tcb, 0);
+#endif
+ __gthread_leave_tls_dtor_context ();
+ }
+}
+
+/* Initialize global data used by the TLS system. */
+static void
+tls_init (void)
+{
+ __GTHREAD_MUTEX_INIT_FUNCTION (&tls_lock);
+}
+
+static void tls_destructor (void) __attribute__ ((destructor));
+static void
+tls_destructor (void)
+{
+#ifdef __RTP__
+ /* All threads but this one should have exited by now. */
+ tls_delete_hook (NULL);
+#else
+ /* Unregister the hook forcibly. The counter of active threads may
+ be incorrect, because constructors (like the C++ library's) and
+ destructors (like this one) run in the context of the shell rather
+ than in a task spawned from this module. */
+ taskDeleteHookDelete ((FUNCPTR)tls_delete_hook);
+#endif
+
+ if (tls_init_guard.done && __gthread_mutex_lock (&tls_lock) != ERROR)
+ semDelete (tls_lock);
+}
+
+/* External interface */
+
+/* Store in KEYP a value which can be passed to __gthread_setspecific/
+ __gthread_getspecific to store and retrieve 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, tls_dtor dtor)
+{
+ __gthread_key_t key;
+
+ __gthread_once (&tls_init_guard, tls_init);
+
+ if (__gthread_mutex_lock (&tls_lock) == ERROR)
+ return errno;
+
+ for (key = 0; key < MAX_KEYS; key++)
+ if (!KEY_VALID_P (key))
+ goto found_slot;
+
+ /* no room */
+ __gthread_mutex_unlock (&tls_lock);
+ return EAGAIN;
+
+ found_slot:
+ tls_keys.generation[key]++; /* making it even */
+ tls_keys.dtor[key] = dtor;
+ *keyp = key;
+ __gthread_mutex_unlock (&tls_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 (&tls_init_guard, tls_init);
+
+ if (__gthread_mutex_lock (&tls_lock) == ERROR)
+ return errno;
+
+ if (!KEY_VALID_P (key))
+ {
+ __gthread_mutex_unlock (&tls_lock);
+ return EINVAL;
+ }
+
+ tls_keys.generation[key]++; /* making it odd */
+ tls_keys.dtor[key] = 0;
+
+ __gthread_mutex_unlock (&tls_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 tls_data *data;
+
+ if (key >= MAX_KEYS)
+ return 0;
+
+ data = __gthread_get_tls_data ();
+
+ if (!data)
+ return 0;
+
+ if (data->generation[key] != tls_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 tls_keys.generation[key] atomically. */
+
+int
+__gthread_setspecific (__gthread_key_t key, void *value)
+{
+ struct tls_data *data;
+ unsigned int generation;
+
+ if (key >= MAX_KEYS)
+ return EINVAL;
+
+ data = __gthread_get_tls_data ();
+ if (!data)
+ {
+ if (__gthread_mutex_lock (&tls_lock) == ERROR)
+ return ENOMEM;
+ if (active_tls_threads == 0)
+ taskDeleteHookAdd ((FUNCPTR)tls_delete_hook);
+ active_tls_threads++;
+ __gthread_mutex_unlock (&tls_lock);
+
+ data = malloc (sizeof (struct tls_data));
+ if (!data)
+ return ENOMEM;
+
+ memset (data, 0, sizeof (struct tls_data));
+ data->owner = &self_owner;
+ __gthread_set_tls_data (data);
+ }
+
+ generation = tls_keys.generation[key];
+
+ if (generation & 1)
+ return EINVAL;
+
+ data->generation[key] = generation;
+ data->values[key] = value;
+
+ return 0;
+}
+#endif /* __GTHREADS */
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