--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgcc/config/gthr-vxworks-tls.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,364 @@
+/* Copyright (C) 2002-2020 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.  */
+
+#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
+
+#include <_vxworks-versions.h>
+
+/* Thread-local storage.
+
+   A gthread TLS key is simply an offset in an array, the address of which
+   we store in a single pointer field associated with the current task.
+
+   On VxWorks 7, we have direct support for __thread variables and use
+   such a variable as the pointer "field".  On other versions, we resort
+   to __gthread_get_tls_data and __gthread_set_tls_data functions provided
+   by the 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;
+
+/* Flag to check whether the delete hook is installed.  Once installed
+   it is only removed when unloading this module.  */
+static volatile int delete_hook_installed;
+
+/* TLS data access internal API.  A straight __thread variable starting with
+   VxWorks 7, a pointer returned by kernel provided routines otherwise.  */
+
+#if _VXWORKS_MAJOR_GE(7)
+
+static __thread struct tls_data *__gthread_tls_data;
+
+#define VX_GET_TLS_DATA() __gthread_tls_data
+#define VX_SET_TLS_DATA(x) __gthread_tls_data = (x)
+
+#define VX_ENTER_TLS_DTOR()
+#define VX_LEAVE_TLS_DTOR()
+
+#else
+
+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);
+
+#define VX_GET_TLS_DATA() __gthread_get_tls_data()
+#define VX_SET_TLS_DATA(x) __gthread_set_tls_data(x)
+
+#define VX_ENTER_TLS_DTOR() __gthread_enter_tls_dtor_context ()
+#define VX_LEAVE_TLS_DTOR() __gthread_leave_tls_dtor_context ()
+
+#endif
+
+/* 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 =
+{
+  { NULL, NULL, NULL, NULL },
+  { 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.  */
+
+void
+tls_delete_hook (void *tcb ATTRIBUTE_UNUSED)
+{
+  struct tls_data *data;
+  __gthread_key_t key;
+
+  data = VX_GET_TLS_DATA();
+
+  if (data && data->owner == &self_owner)
+    {
+      VX_ENTER_TLS_DTOR();
+      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);
+
+      VX_LEAVE_TLS_DTOR();
+      VX_SET_TLS_DATA(NULL);
+    }
+}
+
+/* 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);
+#endif
+  /* Unregister the hook.  */
+  if (delete_hook_installed)
+    taskDeleteHookDelete ((FUNCPTR)tls_delete_hook);
+
+  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 = VX_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 = VX_GET_TLS_DATA();
+
+  if (!data)
+    {
+      if (!delete_hook_installed)
+	{
+	  /* Install the delete hook.  */
+	  if (__gthread_mutex_lock (&tls_lock) == ERROR)
+	    return ENOMEM;
+	  if (!delete_hook_installed)
+	    {
+	      taskDeleteHookAdd ((FUNCPTR)tls_delete_hook);
+	      delete_hook_installed = 1;
+	    }
+	  __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;
+
+      VX_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 */