gcc/libgomp/oacc-mem.c

/* OpenACC Runtime initialization routines

   Copyright (C) 2013-2019 Free Software Foundation, Inc.

   Contributed by Mentor Embedded.

   This file is part of the GNU Offloading and Multi Processing Library
   (libgomp).

   Libgomp 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.

   Libgomp 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/>.  */

#include "openacc.h"
#include "libgomp.h"
#include "gomp-constants.h"
#include "oacc-int.h"
#include <string.h>
#include <assert.h>

/* Return block containing [H->S), or NULL if not contained.  The device lock
   for DEV must be locked on entry, and remains locked on exit.  */

static splay_tree_key
lookup_host (struct gomp_device_descr *dev, void *h, size_t s)
{
  struct splay_tree_key_s node;
  splay_tree_key key;

  node.host_start = (uintptr_t) h;
  node.host_end = (uintptr_t) h + s;

  key = splay_tree_lookup (&dev->mem_map, &node);

  return key;
}

/* Helper for lookup_dev.  Iterate over splay tree.  */

static splay_tree_key
lookup_dev_1 (splay_tree_node node, uintptr_t d, size_t s)
{
  splay_tree_key key = &node->key;
  if (d >= key->tgt->tgt_start && d + s <= key->tgt->tgt_end)
    return key;

  key = NULL;
  if (node->left)
    key = lookup_dev_1 (node->left, d, s);
  if (!key && node->right)
    key = lookup_dev_1 (node->right, d, s);

  return key;
}

/* Return block containing [D->S), or NULL if not contained.

   This iterates over the splay tree.  This is not expected to be a common
   operation.

   The device lock associated with MEM_MAP must be locked on entry, and remains
   locked on exit.  */

static splay_tree_key
lookup_dev (splay_tree mem_map, void *d, size_t s)
{
  if (!mem_map || !mem_map->root)
    return NULL;

  return lookup_dev_1 (mem_map->root, (uintptr_t) d, s);
}


/* OpenACC is silent on how memory exhaustion is indicated.  We return
   NULL.  */

void *
acc_malloc (size_t s)
{
  if (!s)
    return NULL;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();

  assert (thr->dev);

  if (thr->dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return malloc (s);

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);

  void *res = thr->dev->alloc_func (thr->dev->target_id, s);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }

  return res;
}

void
acc_free (void *d)
{
  splay_tree_key k;

  if (!d)
    return;

  struct goacc_thread *thr = goacc_thread ();

  assert (thr && thr->dev);

  struct gomp_device_descr *acc_dev = thr->dev;

  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return free (d);

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);

  gomp_mutex_lock (&acc_dev->lock);

  /* We don't have to call lazy open here, as the ptr value must have
     been returned by acc_malloc.  It's not permitted to pass NULL in
     (unless you got that null from acc_malloc).  */
  if ((k = lookup_dev (&acc_dev->mem_map, d, 1)))
    {
      void *offset = d - k->tgt->tgt_start + k->tgt_offset;
      void *h = k->host_start + offset;
      size_t h_size = k->host_end - k->host_start;
      gomp_mutex_unlock (&acc_dev->lock);
      /* PR92503 "[OpenACC] Behavior of 'acc_free' if the memory space is still
	 used in a mapping".  */
      gomp_fatal ("refusing to free device memory space at %p that is still"
		  " mapped at [%p,+%d]",
		  d, h, (int) h_size);
    }
  else
    gomp_mutex_unlock (&acc_dev->lock);

  if (!acc_dev->free_func (acc_dev->target_id, d))
    gomp_fatal ("error in freeing device memory in %s", __FUNCTION__);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}

static void
memcpy_tofrom_device (bool from, void *d, void *h, size_t s, int async,
		      const char *libfnname)
{
  /* No need to call lazy open here, as the device pointer must have
     been obtained from a routine that did that.  */
  struct goacc_thread *thr = goacc_thread ();

  assert (thr && thr->dev);

  if (thr->dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    {
      if (from)
	memmove (h, d, s);
      else
	memmove (d, h, s);
      return;
    }

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);
  if (profiling_p)
    {
      prof_info.async = async;
      prof_info.async_queue = prof_info.async;
    }

  goacc_aq aq = get_goacc_asyncqueue (async);
  if (from)
    gomp_copy_dev2host (thr->dev, aq, h, d, s);
  else
    gomp_copy_host2dev (thr->dev, aq, d, h, s, /* TODO: cbuf? */ NULL);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}

void
acc_memcpy_to_device (void *d, void *h, size_t s)
{
  memcpy_tofrom_device (false, d, h, s, acc_async_sync, __FUNCTION__);
}

void
acc_memcpy_to_device_async (void *d, void *h, size_t s, int async)
{
  memcpy_tofrom_device (false, d, h, s, async, __FUNCTION__);
}

void
acc_memcpy_from_device (void *h, void *d, size_t s)
{
  memcpy_tofrom_device (true, d, h, s, acc_async_sync, __FUNCTION__);
}

void
acc_memcpy_from_device_async (void *h, void *d, size_t s, int async)
{
  memcpy_tofrom_device (true, d, h, s, async, __FUNCTION__);
}

/* Return the device pointer that corresponds to host data H.  Or NULL
   if no mapping.  */

void *
acc_deviceptr (void *h)
{
  splay_tree_key n;
  void *d;
  void *offset;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *dev = thr->dev;

  if (thr->dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return h;

  /* In the following, no OpenACC Profiling Interface events can possibly be
     generated.  */

  gomp_mutex_lock (&dev->lock);

  n = lookup_host (dev, h, 1);

  if (!n)
    {
      gomp_mutex_unlock (&dev->lock);
      return NULL;
    }

  offset = h - n->host_start;

  d = n->tgt->tgt_start + n->tgt_offset + offset;

  gomp_mutex_unlock (&dev->lock);

  return d;
}

/* Return the host pointer that corresponds to device data D.  Or NULL
   if no mapping.  */

void *
acc_hostptr (void *d)
{
  splay_tree_key n;
  void *h;
  void *offset;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (thr->dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return d;

  /* In the following, no OpenACC Profiling Interface events can possibly be
     generated.  */

  gomp_mutex_lock (&acc_dev->lock);

  n = lookup_dev (&acc_dev->mem_map, d, 1);

  if (!n)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      return NULL;
    }

  offset = d - n->tgt->tgt_start + n->tgt_offset;

  h = n->host_start + offset;

  gomp_mutex_unlock (&acc_dev->lock);

  return h;
}

/* Return 1 if host data [H,+S] is present on the device.  */

int
acc_is_present (void *h, size_t s)
{
  splay_tree_key n;

  if (!s || !h)
    return 0;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (thr->dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return h != NULL;

  /* In the following, no OpenACC Profiling Interface events can possibly be
     generated.  */

  gomp_mutex_lock (&acc_dev->lock);

  n = lookup_host (acc_dev, h, s);

  if (n && ((uintptr_t)h < n->host_start
	    || (uintptr_t)h + s > n->host_end
	    || s > n->host_end - n->host_start))
    n = NULL;

  gomp_mutex_unlock (&acc_dev->lock);

  return n != NULL;
}

/* Create a mapping for host [H,+S] -> device [D,+S] */

void
acc_map_data (void *h, void *d, size_t s)
{
  struct target_mem_desc *tgt = NULL;
  size_t mapnum = 1;
  void *hostaddrs = h;
  void *devaddrs = d;
  size_t sizes = s;
  unsigned short kinds = GOMP_MAP_ALLOC;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    {
      if (d != h)
        gomp_fatal ("cannot map data on shared-memory system");
    }
  else
    {
      struct goacc_thread *thr = goacc_thread ();

      if (!d || !h || !s)
	gomp_fatal ("[%p,+%d]->[%p,+%d] is a bad map",
                    (void *)h, (int)s, (void *)d, (int)s);

      acc_prof_info prof_info;
      acc_api_info api_info;
      bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);

      gomp_mutex_lock (&acc_dev->lock);

      if (lookup_host (acc_dev, h, s))
        {
	  gomp_mutex_unlock (&acc_dev->lock);
	  gomp_fatal ("host address [%p, +%d] is already mapped", (void *)h,
		      (int)s);
	}

      if (lookup_dev (&thr->dev->mem_map, d, s))
        {
	  gomp_mutex_unlock (&acc_dev->lock);
	  gomp_fatal ("device address [%p, +%d] is already mapped", (void *)d,
		      (int)s);
	}

      gomp_mutex_unlock (&acc_dev->lock);

      tgt = gomp_map_vars (acc_dev, mapnum, &hostaddrs, &devaddrs, &sizes,
			   &kinds, true, GOMP_MAP_VARS_ENTER_DATA);
      assert (tgt);
      splay_tree_key n = tgt->list[0].key;
      assert (n->refcount == 1);
      assert (n->dynamic_refcount == 0);
      /* Special reference counting behavior.  */
      n->refcount = REFCOUNT_INFINITY;

      if (profiling_p)
	{
	  thr->prof_info = NULL;
	  thr->api_info = NULL;
	}
    }
}

void
acc_unmap_data (void *h)
{
  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  /* No need to call lazy open, as the address must have been mapped.  */

  /* This is a no-op on shared-memory targets.  */
  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return;

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);

  size_t host_size;

  gomp_mutex_lock (&acc_dev->lock);

  splay_tree_key n = lookup_host (acc_dev, h, 1);
  struct target_mem_desc *t;

  if (!n)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("%p is not a mapped block", (void *)h);
    }

  host_size = n->host_end - n->host_start;

  if (n->host_start != (uintptr_t) h)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("[%p,%d] surrounds %p",
		  (void *) n->host_start, (int) host_size, (void *) h);
    }
  /* TODO This currently doesn't catch 'REFCOUNT_INFINITY' usage different from
     'acc_map_data'.  Maybe 'dynamic_refcount' can be used for disambiguating
     the different 'REFCOUNT_INFINITY' cases, or simply separate
     'REFCOUNT_INFINITY' values per different usage ('REFCOUNT_ACC_MAP_DATA'
     etc.)?  */
  else if (n->refcount != REFCOUNT_INFINITY)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("refusing to unmap block [%p,+%d] that has not been mapped"
		  " by 'acc_map_data'",
		  (void *) h, (int) host_size);
    }

  t = n->tgt;

  if (t->refcount == 1)
    {
      /* This is the last reference, so pull the descriptor off the
         chain.  This prevents 'gomp_unmap_tgt' via 'gomp_remove_var' from
         freeing the device memory. */
      t->tgt_end = 0;
      t->to_free = 0;
    }

  bool is_tgt_unmapped = gomp_remove_var (acc_dev, n);
  assert (is_tgt_unmapped);

  gomp_mutex_unlock (&acc_dev->lock);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}


/* Enter a dynamic mapping.

   Return the device pointer.  */

static void *
goacc_enter_data (void *h, size_t s, unsigned short kind, int async)
{
  void *d;
  splay_tree_key n;

  if (!h || !s)
    gomp_fatal ("[%p,+%d] is a bad range", (void *)h, (int)s);

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return h;

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);
  if (profiling_p)
    {
      prof_info.async = async;
      prof_info.async_queue = prof_info.async;
    }

  gomp_mutex_lock (&acc_dev->lock);

  n = lookup_host (acc_dev, h, s);
  if (n)
    {
      /* Present. */
      d = (void *) (n->tgt->tgt_start + n->tgt_offset + h - n->host_start);

      if ((h + s) > (void *)n->host_end)
	{
	  gomp_mutex_unlock (&acc_dev->lock);
	  gomp_fatal ("[%p,+%d] not mapped", (void *)h, (int)s);
	}

      assert (n->refcount != REFCOUNT_LINK);
      if (n->refcount != REFCOUNT_INFINITY)
	n->refcount++;
      n->dynamic_refcount++;

      gomp_mutex_unlock (&acc_dev->lock);
    }
  else
    {
      struct target_mem_desc *tgt;
      size_t mapnum = 1;
      void *hostaddrs = h;

      gomp_mutex_unlock (&acc_dev->lock);

      goacc_aq aq = get_goacc_asyncqueue (async);

      tgt = gomp_map_vars_async (acc_dev, aq, mapnum, &hostaddrs, NULL, &s,
				 &kind, true, GOMP_MAP_VARS_ENTER_DATA);
      assert (tgt);
      n = tgt->list[0].key;
      assert (n->refcount == 1);
      assert (n->dynamic_refcount == 0);
      n->dynamic_refcount++;

      d = tgt->to_free;
    }

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }

  return d;
}

void *
acc_create (void *h, size_t s)
{
  return goacc_enter_data (h, s, GOMP_MAP_ALLOC, acc_async_sync);
}

void
acc_create_async (void *h, size_t s, int async)
{
  goacc_enter_data (h, s, GOMP_MAP_ALLOC, async);
}

/* acc_present_or_create used to be what acc_create is now.  */
/* acc_pcreate is acc_present_or_create by a different name.  */
#ifdef HAVE_ATTRIBUTE_ALIAS
strong_alias (acc_create, acc_present_or_create)
strong_alias (acc_create, acc_pcreate)
#else
void *
acc_present_or_create (void *h, size_t s)
{
  return acc_create (h, s);
}

void *
acc_pcreate (void *h, size_t s)
{
  return acc_create (h, s);
}
#endif

void *
acc_copyin (void *h, size_t s)
{
  return goacc_enter_data (h, s, GOMP_MAP_TO, acc_async_sync);
}

void
acc_copyin_async (void *h, size_t s, int async)
{
  goacc_enter_data (h, s, GOMP_MAP_TO, async);
}

/* acc_present_or_copyin used to be what acc_copyin is now.  */
/* acc_pcopyin is acc_present_or_copyin by a different name.  */
#ifdef HAVE_ATTRIBUTE_ALIAS
strong_alias (acc_copyin, acc_present_or_copyin)
strong_alias (acc_copyin, acc_pcopyin)
#else
void *
acc_present_or_copyin (void *h, size_t s)
{
  return acc_copyin (h, s);
}

void *
acc_pcopyin (void *h, size_t s)
{
  return acc_copyin (h, s);
}
#endif


/* Exit a dynamic mapping.  */

static void
goacc_exit_data (void *h, size_t s, unsigned short kind, int async)
{
  /* No need to call lazy open, as the data must already have been
     mapped.  */

  kind &= 0xff;

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return;

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);
  if (profiling_p)
    {
      prof_info.async = async;
      prof_info.async_queue = prof_info.async;
    }

  gomp_mutex_lock (&acc_dev->lock);

  splay_tree_key n = lookup_host (acc_dev, h, s);
  if (!n)
    /* PR92726, RP92970, PR92984: no-op.  */
    goto out;

  if ((uintptr_t) h < n->host_start || (uintptr_t) h + s > n->host_end)
    {
      size_t host_size = n->host_end - n->host_start;
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("[%p,+%d] outside mapped block [%p,+%d]",
		  (void *) h, (int) s, (void *) n->host_start, (int) host_size);
    }

  assert (n->refcount != REFCOUNT_LINK);
  if (n->refcount != REFCOUNT_INFINITY
      && n->refcount < n->dynamic_refcount)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("Dynamic reference counting assert fail\n");
    }

  bool finalize = (kind == GOMP_MAP_DELETE
		   || kind == GOMP_MAP_FORCE_FROM);
  if (finalize)
    {
      if (n->refcount != REFCOUNT_INFINITY)
	n->refcount -= n->dynamic_refcount;
      n->dynamic_refcount = 0;
    }
  else if (n->dynamic_refcount)
    {
      if (n->refcount != REFCOUNT_INFINITY)
	n->refcount--;
      n->dynamic_refcount--;
    }

  if (n->refcount == 0)
    {
      goacc_aq aq = get_goacc_asyncqueue (async);

      bool copyout = (kind == GOMP_MAP_FROM
		      || kind == GOMP_MAP_FORCE_FROM);
      if (copyout)
	{
	  void *d = (void *) (n->tgt->tgt_start + n->tgt_offset
			      + (uintptr_t) h - n->host_start);
	  gomp_copy_dev2host (acc_dev, aq, h, d, s);
	}

      if (aq)
	/* TODO We can't do the 'is_tgt_unmapped' checking -- see the
	   'gomp_unref_tgt' comment in
	   <http://mid.mail-archive.com/878snl36eu.fsf@euler.schwinge.homeip.net>;
	   PR92881.  */
	gomp_remove_var_async (acc_dev, n, aq);
      else
	{
	  bool is_tgt_unmapped = gomp_remove_var (acc_dev, n);
	  assert (is_tgt_unmapped);
	}
    }

 out:
  gomp_mutex_unlock (&acc_dev->lock);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}

void
acc_delete (void *h , size_t s)
{
  goacc_exit_data (h, s, GOMP_MAP_RELEASE, acc_async_sync);
}

void
acc_delete_async (void *h , size_t s, int async)
{
  goacc_exit_data (h, s, GOMP_MAP_RELEASE, async);
}

void
acc_delete_finalize (void *h , size_t s)
{
  goacc_exit_data (h, s, GOMP_MAP_DELETE, acc_async_sync);
}

void
acc_delete_finalize_async (void *h , size_t s, int async)
{
  goacc_exit_data (h, s, GOMP_MAP_DELETE, async);
}

void
acc_copyout (void *h, size_t s)
{
  goacc_exit_data (h, s, GOMP_MAP_FROM, acc_async_sync);
}

void
acc_copyout_async (void *h, size_t s, int async)
{
  goacc_exit_data (h, s, GOMP_MAP_FROM, async);
}

void
acc_copyout_finalize (void *h, size_t s)
{
  goacc_exit_data (h, s, GOMP_MAP_FORCE_FROM, acc_async_sync);
}

void
acc_copyout_finalize_async (void *h, size_t s, int async)
{
  goacc_exit_data (h, s, GOMP_MAP_FORCE_FROM, async);
}

static void
update_dev_host (int is_dev, void *h, size_t s, int async)
{
  splay_tree_key n;
  void *d;

  goacc_lazy_initialize ();

  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
    return;

  /* Fortran optional arguments that are non-present result in a
     NULL host address here.  This can safely be ignored as it is
     not possible to 'update' a non-present optional argument.  */
  if (h == NULL)
    return;

  acc_prof_info prof_info;
  acc_api_info api_info;
  bool profiling_p = GOACC_PROFILING_SETUP_P (thr, &prof_info, &api_info);
  if (profiling_p)
    {
      prof_info.async = async;
      prof_info.async_queue = prof_info.async;
    }

  gomp_mutex_lock (&acc_dev->lock);

  n = lookup_host (acc_dev, h, s);

  if (!n)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("[%p,%d] is not mapped", h, (int)s);
    }

  d = (void *) (n->tgt->tgt_start + n->tgt_offset
		+ (uintptr_t) h - n->host_start);

  goacc_aq aq = get_goacc_asyncqueue (async);

  if (is_dev)
    gomp_copy_host2dev (acc_dev, aq, d, h, s, /* TODO: cbuf? */ NULL);
  else
    gomp_copy_dev2host (acc_dev, aq, h, d, s);

  gomp_mutex_unlock (&acc_dev->lock);

  if (profiling_p)
    {
      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}

void
acc_update_device (void *h, size_t s)
{
  update_dev_host (1, h, s, acc_async_sync);
}

void
acc_update_device_async (void *h, size_t s, int async)
{
  update_dev_host (1, h, s, async);
}

void
acc_update_self (void *h, size_t s)
{
  update_dev_host (0, h, s, acc_async_sync);
}

void
acc_update_self_async (void *h, size_t s, int async)
{
  update_dev_host (0, h, s, async);
}


/* OpenACC 'enter data', 'exit data': 'GOACC_enter_exit_data' and its helper
   functions.  */

/* Special handling for 'GOMP_MAP_POINTER', 'GOMP_MAP_TO_PSET'.

   Only the first mapping is considered in reference counting; the following
   ones implicitly follow suit.  Similarly, 'copyout' ('force_copyfrom') is
   done only for the first mapping.  */

static void
goacc_insert_pointer (size_t mapnum, void **hostaddrs, size_t *sizes,
		      void *kinds, int async)
{
  struct target_mem_desc *tgt;
  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;

  if (*hostaddrs == NULL)
    return;

  if (acc_is_present (*hostaddrs, *sizes))
    {
      splay_tree_key n;
      gomp_mutex_lock (&acc_dev->lock);
      n = lookup_host (acc_dev, *hostaddrs, *sizes);
      assert (n->refcount != REFCOUNT_INFINITY
	      && n->refcount != REFCOUNT_LINK);
      gomp_mutex_unlock (&acc_dev->lock);

      tgt = n->tgt;
      for (size_t i = 0; i < tgt->list_count; i++)
	if (tgt->list[i].key == n)
	  {
	    for (size_t j = 0; j < mapnum; j++)
	      if (i + j < tgt->list_count && tgt->list[i + j].key)
		{
		  tgt->list[i + j].key->refcount++;
		  tgt->list[i + j].key->dynamic_refcount++;
		}
	    return;
	  }
      /* Should not reach here.  */
      gomp_fatal ("Dynamic refcount incrementing failed for pointer/pset");
    }

  gomp_debug (0, "  %s: prepare mappings\n", __FUNCTION__);
  goacc_aq aq = get_goacc_asyncqueue (async);
  tgt = gomp_map_vars_async (acc_dev, aq, mapnum, hostaddrs,
			     NULL, sizes, kinds, true, GOMP_MAP_VARS_ENTER_DATA);
  assert (tgt);
  splay_tree_key n = tgt->list[0].key;
  assert (n->refcount == 1);
  assert (n->dynamic_refcount == 0);
  n->dynamic_refcount++;
  gomp_debug (0, "  %s: mappings prepared\n", __FUNCTION__);
}

static void
goacc_remove_pointer (void *h, size_t s, bool force_copyfrom, int async,
		      int finalize)
{
  struct goacc_thread *thr = goacc_thread ();
  struct gomp_device_descr *acc_dev = thr->dev;
  splay_tree_key n;
  struct target_mem_desc *t;

  if (!acc_is_present (h, s))
    return;

  gomp_mutex_lock (&acc_dev->lock);

  n = lookup_host (acc_dev, h, 1);

  if (!n)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("%p is not a mapped block", (void *)h);
    }

  gomp_debug (0, "  %s: restore mappings\n", __FUNCTION__);

  t = n->tgt;

  assert (n->refcount != REFCOUNT_INFINITY
	  && n->refcount != REFCOUNT_LINK);
  if (n->refcount < n->dynamic_refcount)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("Dynamic reference counting assert fail\n");
    }

  if (finalize)
    {
      n->refcount -= n->dynamic_refcount;
      n->dynamic_refcount = 0;
    }
  else if (n->dynamic_refcount)
    {
      n->refcount--;
      n->dynamic_refcount--;
    }

  if (n->refcount == 0)
    {
      goacc_aq aq = get_goacc_asyncqueue (async);

      if (force_copyfrom)
	{
	  void *d = (void *) (t->tgt_start + n->tgt_offset
			      + (uintptr_t) h - n->host_start);

	  gomp_copy_dev2host (acc_dev, aq, h, d, s);
	}

      if (aq)
	{
	  /* TODO The way the following code is currently implemented, we need
	     the 'is_tgt_unmapped' return value from 'gomp_remove_var', so
	     can't use 'gomp_remove_var_async' here -- see the 'gomp_unref_tgt'
	     comment in
	     <http://mid.mail-archive.com/878snl36eu.fsf@euler.schwinge.homeip.net>;
	     PR92881 -- so have to synchronize here.  */
	  if (!acc_dev->openacc.async.synchronize_func (aq))
	    {
	      gomp_mutex_unlock (&acc_dev->lock);
	      gomp_fatal ("synchronize failed");
	    }
	}
      bool is_tgt_unmapped = false;
      for (size_t i = 0; i < t->list_count; i++)
	{
	  is_tgt_unmapped = gomp_remove_var (acc_dev, t->list[i].key);
	  if (is_tgt_unmapped)
	    break;
	}
      assert (is_tgt_unmapped);
    }

  gomp_mutex_unlock (&acc_dev->lock);

  gomp_debug (0, "  %s: mappings restored\n", __FUNCTION__);
}

/* Return the number of mappings associated with 'GOMP_MAP_TO_PSET' or
   'GOMP_MAP_POINTER'.  */

static int
find_pointer (int pos, size_t mapnum, unsigned short *kinds)
{
  if (pos + 1 >= mapnum)
    return 0;

  unsigned char kind = kinds[pos+1] & 0xff;

  if (kind == GOMP_MAP_TO_PSET)
    return 3;
  else if (kind == GOMP_MAP_POINTER)
    return 2;

  return 0;
}

void
GOACC_enter_exit_data (int flags_m, size_t mapnum, void **hostaddrs,
		       size_t *sizes, unsigned short *kinds, int async,
		       int num_waits, ...)
{
  int flags = GOACC_FLAGS_UNMARSHAL (flags_m);

  struct goacc_thread *thr;
  struct gomp_device_descr *acc_dev;
  bool data_enter = false;
  size_t i;

  goacc_lazy_initialize ();

  thr = goacc_thread ();
  acc_dev = thr->dev;

  /* Determine if this is an "acc enter data".  */
  for (i = 0; i < mapnum; ++i)
    {
      unsigned char kind = kinds[i] & 0xff;

      if (kind == GOMP_MAP_POINTER || kind == GOMP_MAP_TO_PSET)
	continue;

      if (kind == GOMP_MAP_FORCE_ALLOC
	  || kind == GOMP_MAP_FORCE_PRESENT
	  || kind == GOMP_MAP_FORCE_TO
	  || kind == GOMP_MAP_TO
	  || kind == GOMP_MAP_ALLOC)
	{
	  data_enter = true;
	  break;
	}

      if (kind == GOMP_MAP_RELEASE
	  || kind == GOMP_MAP_DELETE
	  || kind == GOMP_MAP_FROM
	  || kind == GOMP_MAP_FORCE_FROM)
	break;

      gomp_fatal (">>>> GOACC_enter_exit_data UNHANDLED kind 0x%.2x",
		      kind);
    }

  bool profiling_p = GOACC_PROFILING_DISPATCH_P (true);

  acc_prof_info prof_info;
  if (profiling_p)
    {
      thr->prof_info = &prof_info;

      prof_info.event_type
	= data_enter ? acc_ev_enter_data_start : acc_ev_exit_data_start;
      prof_info.valid_bytes = _ACC_PROF_INFO_VALID_BYTES;
      prof_info.version = _ACC_PROF_INFO_VERSION;
      prof_info.device_type = acc_device_type (acc_dev->type);
      prof_info.device_number = acc_dev->target_id;
      prof_info.thread_id = -1;
      prof_info.async = async;
      prof_info.async_queue = prof_info.async;
      prof_info.src_file = NULL;
      prof_info.func_name = NULL;
      prof_info.line_no = -1;
      prof_info.end_line_no = -1;
      prof_info.func_line_no = -1;
      prof_info.func_end_line_no = -1;
    }
  acc_event_info enter_exit_data_event_info;
  if (profiling_p)
    {
      enter_exit_data_event_info.other_event.event_type
	= prof_info.event_type;
      enter_exit_data_event_info.other_event.valid_bytes
	= _ACC_OTHER_EVENT_INFO_VALID_BYTES;
      enter_exit_data_event_info.other_event.parent_construct
	= data_enter ? acc_construct_enter_data : acc_construct_exit_data;
      enter_exit_data_event_info.other_event.implicit = 0;
      enter_exit_data_event_info.other_event.tool_info = NULL;
    }
  acc_api_info api_info;
  if (profiling_p)
    {
      thr->api_info = &api_info;

      api_info.device_api = acc_device_api_none;
      api_info.valid_bytes = _ACC_API_INFO_VALID_BYTES;
      api_info.device_type = prof_info.device_type;
      api_info.vendor = -1;
      api_info.device_handle = NULL;
      api_info.context_handle = NULL;
      api_info.async_handle = NULL;
    }

  if (profiling_p)
    goacc_profiling_dispatch (&prof_info, &enter_exit_data_event_info,
			      &api_info);

  if ((acc_dev->capabilities & GOMP_OFFLOAD_CAP_SHARED_MEM)
      || (flags & GOACC_FLAG_HOST_FALLBACK))
    {
      prof_info.device_type = acc_device_host;
      api_info.device_type = prof_info.device_type;

      goto out_prof;
    }

  if (num_waits)
    {
      va_list ap;

      va_start (ap, num_waits);
      goacc_wait (async, num_waits, &ap);
      va_end (ap);
    }

  /* In c, non-pointers and arrays are represented by a single data clause.
     Dynamically allocated arrays and subarrays are represented by a data
     clause followed by an internal GOMP_MAP_POINTER.

     In fortran, scalars and not allocated arrays are represented by a
     single data clause. Allocated arrays and subarrays have three mappings:
     1) the original data clause, 2) a PSET 3) a pointer to the array data.
  */

  if (data_enter)
    {
      for (i = 0; i < mapnum; i++)
	{
	  unsigned char kind = kinds[i] & 0xff;

	  /* Scan for pointers and PSETs.  */
	  int pointer = find_pointer (i, mapnum, kinds);

	  if (!pointer)
	    {
	      switch (kind)
		{
		case GOMP_MAP_ALLOC:
		case GOMP_MAP_FORCE_ALLOC:
		  acc_create_async (hostaddrs[i], sizes[i], async);
		  break;
		case GOMP_MAP_TO:
		case GOMP_MAP_FORCE_TO:
		  acc_copyin_async (hostaddrs[i], sizes[i], async);
		  break;
		default:
		  gomp_fatal (">>>> GOACC_enter_exit_data UNHANDLED kind 0x%.2x",
			      kind);
		  break;
		}
	    }
	  else
	    {
	      goacc_insert_pointer (pointer, &hostaddrs[i], &sizes[i], &kinds[i],
				    async);
	      /* Increment 'i' by two because OpenACC requires fortran
		 arrays to be contiguous, so each PSET is associated with
		 one of MAP_FORCE_ALLOC/MAP_FORCE_PRESET/MAP_FORCE_TO, and
		 one MAP_POINTER.  */
	      i += pointer - 1;
	    }
	}
    }
  else
    for (i = 0; i < mapnum; ++i)
      {
	unsigned char kind = kinds[i] & 0xff;

	bool finalize = (kind == GOMP_MAP_DELETE
			 || kind == GOMP_MAP_FORCE_FROM);

	int pointer = find_pointer (i, mapnum, kinds);

	if (!pointer)
	  {
	    switch (kind)
	      {
	      case GOMP_MAP_RELEASE:
	      case GOMP_MAP_DELETE:
		if (finalize)
		  acc_delete_finalize_async (hostaddrs[i], sizes[i], async);
		else
		  acc_delete_async (hostaddrs[i], sizes[i], async);
		break;
	      case GOMP_MAP_FROM:
	      case GOMP_MAP_FORCE_FROM:
		if (finalize)
		  acc_copyout_finalize_async (hostaddrs[i], sizes[i], async);
		else
		  acc_copyout_async (hostaddrs[i], sizes[i], async);
		break;
	      default:
		gomp_fatal (">>>> GOACC_enter_exit_data UNHANDLED kind 0x%.2x",
			    kind);
		break;
	      }
	  }
	else
	  {
	    bool copyfrom = (kind == GOMP_MAP_FORCE_FROM
			     || kind == GOMP_MAP_FROM);
	    goacc_remove_pointer (hostaddrs[i], sizes[i], copyfrom, async,
				  finalize);
	    /* See the above comment.  */
	    i += pointer - 1;
	  }
      }

 out_prof:
  if (profiling_p)
    {
      prof_info.event_type
	= data_enter ? acc_ev_enter_data_end : acc_ev_exit_data_end;
      enter_exit_data_event_info.other_event.event_type = prof_info.event_type;
      goacc_profiling_dispatch (&prof_info, &enter_exit_data_event_info,
				&api_info);

      thr->prof_info = NULL;
      thr->api_info = NULL;
    }
}