OpenACC reference count overhaul

[gcc.git] / 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->virtual_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);

  gomp_mutex_lock (&acc_dev->lock);

  splay_tree_key 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);
    }

  size_t 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 'virtual_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);
    }

  splay_tree_remove (&acc_dev->mem_map, n);

  struct target_mem_desc *tgt = n->tgt;

  if (tgt->refcount == REFCOUNT_INFINITY)
    {
      gomp_mutex_unlock (&acc_dev->lock);
      gomp_fatal ("cannot unmap target block");
    }
  else if (tgt->refcount > 1)
    tgt->refcount--;
  else
    {
      free (tgt->array);
      free (tgt);
    }

  gomp_mutex_unlock (&acc_dev->lock);

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


/* Enter dynamic mapping for a single datum.  Return the device pointer.  */

static void *
goacc_enter_datum (void **hostaddrs, size_t *sizes, void *kinds, int async)
{
  void *d;
  splay_tree_key n;

  if (!hostaddrs[0] || !sizes[0])
    gomp_fatal ("[%p,+%d] is a bad range", hostaddrs[0], (int) sizes[0]);

  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 hostaddrs[0];

  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, hostaddrs[0], sizes[0]);
  if (n)
    {
      void *h = hostaddrs[0];
      size_t s = sizes[0];

      /* 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->virtual_refcount++;
        }

      gomp_mutex_unlock (&acc_dev->lock);
    }
  else
    {
      const size_t mapnum = 1;

      gomp_mutex_unlock (&acc_dev->lock);

      goacc_aq aq = get_goacc_asyncqueue (async);

      gomp_map_vars_async (acc_dev, aq, mapnum, hostaddrs, NULL, sizes, kinds,
                           true, GOMP_MAP_VARS_OPENACC_ENTER_DATA);

      gomp_mutex_lock (&acc_dev->lock);
      n = lookup_host (acc_dev, hostaddrs[0], sizes[0]);
      assert (n != NULL);
      assert (n->tgt_offset == 0);
      assert ((uintptr_t) hostaddrs[0] == n->host_start);
      d = (void *) n->tgt->tgt_start;
      gomp_mutex_unlock (&acc_dev->lock);
    }

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

  return d;
}

void *
acc_create (void *h, size_t s)
{
  unsigned short kinds[1] = { GOMP_MAP_ALLOC };
  return goacc_enter_datum (&h, &s, &kinds, acc_async_sync);
}

void
acc_create_async (void *h, size_t s, int async)
{
  unsigned short kinds[1] = { GOMP_MAP_ALLOC };
  goacc_enter_datum (&h, &s, &kinds, 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)
{
  unsigned short kinds[1] = { GOMP_MAP_TO };
  return goacc_enter_datum (&h, &s, &kinds, acc_async_sync);
}

void
acc_copyin_async (void *h, size_t s, int async)
{
  unsigned short kinds[1] = { GOMP_MAP_TO };
  goacc_enter_datum (&h, &s, &kinds, 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 for a single variable.  */

static void
goacc_exit_datum (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);
    }

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

  if (n->virtual_refcount > 0)
    {
      if (n->refcount != REFCOUNT_INFINITY)
        n->refcount--;
      n->virtual_refcount--;
    }
  else if (n->refcount > 0 && n->refcount != REFCOUNT_INFINITY)
    n->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_datum (h, s, GOMP_MAP_RELEASE, acc_async_sync);
}

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

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

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

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

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

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

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

/* Some types of (pointer) variables use several consecutive mappings, which
   must be treated as a group for enter/exit data directives.  This function
   returns the last mapping in such a group (inclusive), or POS for singleton
   mappings.  */

static int
find_group_last (int pos, size_t mapnum, unsigned short *kinds)
{
  unsigned char kind0 = kinds[pos] & 0xff;
  int first_pos = pos, last_pos = pos;

  if (kind0 == GOMP_MAP_TO_PSET)
    {
      while (pos + 1 < mapnum && (kinds[pos + 1] & 0xff) == GOMP_MAP_POINTER)
        last_pos = ++pos;
      /* We expect at least one GOMP_MAP_POINTER after a GOMP_MAP_TO_PSET.  */
      assert (last_pos > first_pos);
    }
  else
    {
      /* GOMP_MAP_ALWAYS_POINTER can only appear directly after some other
         mapping.  */
      if (pos + 1 < mapnum
          && (kinds[pos + 1] & 0xff) == GOMP_MAP_ALWAYS_POINTER)
        return pos + 1;

      /* We can have one or several GOMP_MAP_POINTER mappings after a to/from
         (etc.) mapping.  */
      while (pos + 1 < mapnum && (kinds[pos + 1] & 0xff) == GOMP_MAP_POINTER)
        last_pos = ++pos;
    }

  return last_pos;
}

/* Map variables for OpenACC "enter data".  We can't just call
   gomp_map_vars_async once, because individual mapped variables might have
   "exit data" called for them at different times.  */

static void
goacc_enter_data_internal (struct gomp_device_descr *acc_dev, size_t mapnum,
                           void **hostaddrs, size_t *sizes,
                           unsigned short *kinds, goacc_aq aq)
{
  for (size_t i = 0; i < mapnum; i++)
    {
      int group_last = find_group_last (i, mapnum, kinds);

      gomp_map_vars_async (acc_dev, aq,
                           (group_last - i) + 1,
                           &hostaddrs[i], NULL,
                           &sizes[i], &kinds[i], true,
                           GOMP_MAP_VARS_OPENACC_ENTER_DATA);

      i = group_last;
    }
}

/* Unmap variables for OpenACC "exit data".  */

static void
goacc_exit_data_internal (struct gomp_device_descr *acc_dev, size_t mapnum,
                          void **hostaddrs, size_t *sizes,
                          unsigned short *kinds, goacc_aq aq)
{
  gomp_mutex_lock (&acc_dev->lock);

  for (size_t i = 0; i < mapnum; ++i)
    {
      unsigned char kind = kinds[i] & 0xff;
      bool copyfrom = false;
      bool finalize = false;

      if (kind == GOMP_MAP_FORCE_FROM
          || kind == GOMP_MAP_DELETE)
        finalize = true;

      switch (kind)
        {
        case GOMP_MAP_FROM:
        case GOMP_MAP_FORCE_FROM:
        case GOMP_MAP_ALWAYS_FROM:
          copyfrom = true;
          /* Fallthrough.  */

        case GOMP_MAP_TO_PSET:
        case GOMP_MAP_POINTER:
        case GOMP_MAP_DELETE:
        case GOMP_MAP_RELEASE:
          {
            struct splay_tree_key_s cur_node;
            size_t size;
            if (kind == GOMP_MAP_POINTER)
              size = sizeof (void *);
            else
              size = sizes[i];
            cur_node.host_start = (uintptr_t) hostaddrs[i];
            cur_node.host_end = cur_node.host_start + size;
            splay_tree_key n
              = splay_tree_lookup (&acc_dev->mem_map, &cur_node);

            if (n == NULL)
              continue;

            if (finalize)
              {
                if (n->refcount != REFCOUNT_INFINITY)
                  n->refcount -= n->virtual_refcount;
                n->virtual_refcount = 0;
              }

            if (n->virtual_refcount > 0)
              {
                if (n->refcount != REFCOUNT_INFINITY)
                  n->refcount--;
                n->virtual_refcount--;
              }
            else if (n->refcount > 0 && n->refcount != REFCOUNT_INFINITY)
              n->refcount--;

            if (copyfrom
                && (kind != GOMP_MAP_FROM || n->refcount == 0))
              gomp_copy_dev2host (acc_dev, aq, (void *) cur_node.host_start,
                                  (void *) (n->tgt->tgt_start + n->tgt_offset
                                            + cur_node.host_start
                                            - n->host_start),
                                  cur_node.host_end - cur_node.host_start);

            if (n->refcount == 0)
              gomp_remove_var_async (acc_dev, n, aq);
          }
          break;
        default:
          gomp_fatal (">>>> goacc_exit_data_internal UNHANDLED kind 0x%.2x",
                          kind);
        }
    }

  gomp_mutex_unlock (&acc_dev->lock);
}

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);
    }

  goacc_aq aq = get_goacc_asyncqueue (async);

  if (data_enter)
    goacc_enter_data_internal (acc_dev, mapnum, hostaddrs, sizes, kinds, aq);
  else
    goacc_exit_data_internal (acc_dev, mapnum, hostaddrs, sizes, kinds, aq);

 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;
    }
}