libgomp/config/accel/target-indirect.c

   1 /* Copyright (C) 2023-2024 Free Software Foundation, Inc.
   2
   3    Contributed by Siemens.
   4
   5    This file is part of the GNU Offloading and Multi Processing Library
   6    (libgomp).
   7
   8    Libgomp is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3, or (at your option)
  11    any later version.
  12
  13    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  14    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  15    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16    more details.
  17
  18    Under Section 7 of GPL version 3, you are granted additional
  19    permissions described in the GCC Runtime Library Exception, version
  20    3.1, as published by the Free Software Foundation.
  21
  22    You should have received a copy of the GNU General Public License and
  23    a copy of the GCC Runtime Library Exception along with this program;
  24    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25    <http://www.gnu.org/licenses/>.  */
  26
  27 #include <assert.h>
  28 #include "libgomp.h"
  29
  30 #define splay_tree_prefix indirect
  31 #define splay_tree_c
  32 #include "splay-tree.h"
  33
  34 volatile void **GOMP_INDIRECT_ADDR_MAP = NULL;
  35
  36 /* Use a splay tree to lookup the target address instead of using a
  37    linear search.  */
  38 #define USE_SPLAY_TREE_LOOKUP
  39
  40 #ifdef USE_SPLAY_TREE_LOOKUP
  41
  42 static struct indirect_splay_tree_s indirect_map;
  43 static indirect_splay_tree_node indirect_array = NULL;
  44
  45 /* Build the splay tree used for host->target address lookups.  */
  46
  47 void
  48 build_indirect_map (void)
  49 {
  50   size_t num_ind_funcs = 0;
  51   volatile void **map_entry;
  52   static int lock = 0; /* == gomp_mutex_t lock; gomp_mutex_init (&lock); */
  53
  54   if (!GOMP_INDIRECT_ADDR_MAP)
  55     return;
  56
  57   gomp_mutex_lock (&lock);
  58
  59   if (!indirect_array)
  60     {
  61       /* Count the number of entries in the NULL-terminated address map.  */
  62       for (map_entry = GOMP_INDIRECT_ADDR_MAP; *map_entry;
  63            map_entry += 2, num_ind_funcs++);
  64
  65       /* Build splay tree for address lookup.  */
  66       indirect_array = gomp_malloc (num_ind_funcs * sizeof (*indirect_array));
  67       indirect_splay_tree_node array = indirect_array;
  68       map_entry = GOMP_INDIRECT_ADDR_MAP;
  69
  70       for (int i = 0; i < num_ind_funcs; i++, array++)
  71         {
  72           indirect_splay_tree_key k = &array->key;
  73           k->host_addr = (uint64_t) *map_entry++;
  74           k->target_addr = (uint64_t) *map_entry++;
  75           array->left = NULL;
  76           array->right = NULL;
  77           indirect_splay_tree_insert (&indirect_map, array);
  78         }
  79     }
  80
  81   gomp_mutex_unlock (&lock);
  82 }
  83
  84 void *
  85 GOMP_target_map_indirect_ptr (void *ptr)
  86 {
  87   /* NULL pointers always resolve to NULL.  */
  88   if (!ptr)
  89     return ptr;
  90
  91   assert (indirect_array);
  92
  93   struct indirect_splay_tree_key_s k;
  94   indirect_splay_tree_key node = NULL;
  95
  96   k.host_addr = (uint64_t) ptr;
  97   node = indirect_splay_tree_lookup (&indirect_map, &k);
  98
  99   return node ? (void *) node->target_addr : ptr;
 100 }
 101
 102 #else
 103
 104 void
 105 build_indirect_map (void)
 106 {
 107 }
 108
 109 void *
 110 GOMP_target_map_indirect_ptr (void *ptr)
 111 {
 112   /* NULL pointers always resolve to NULL.  */
 113   if (!ptr)
 114     return ptr;
 115
 116   assert (GOMP_INDIRECT_ADDR_MAP);
 117
 118   for (volatile void **map_entry = GOMP_INDIRECT_ADDR_MAP; *map_entry;
 119        map_entry += 2)
 120     if (*map_entry == ptr)
 121       return (void *) *(map_entry + 1);
 122
 123   return ptr;
 124 }
 125
 126 #endif