src/mesa/drivers/dri/r300/compiler/radeon_remove_constants.c

   1 /*
   2  * Copyright (C) 2010 Marek Olšák <maraeo@gmail.com>
   3  *
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining
   7  * a copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sublicense, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial
  16  * portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  21  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  22  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  23  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  24  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  */
  27
  28 #include "radeon_remove_constants.h"
  29 #include "radeon_dataflow.h"
  30
  31 struct mark_used_data {
  32         unsigned char * const_used;
  33         unsigned * has_rel_addr;
  34 };
  35
  36 static void remap_regs(void * userdata, struct rc_instruction * inst,
  37                         rc_register_file * pfile, unsigned int * pindex)
  38 {
  39         unsigned *inv_remap_table = userdata;
  40
  41         if (*pfile == RC_FILE_CONSTANT) {
  42                 *pindex = inv_remap_table[*pindex];
  43         }
  44 }
  45
  46 static void mark_used(void * userdata, struct rc_instruction * inst,
  47                                                 struct rc_src_register * src)
  48 {
  49         struct mark_used_data * d = userdata;
  50
  51         if (src->File == RC_FILE_CONSTANT) {
  52                 if (src->RelAddr) {
  53                         *d->has_rel_addr = 1;
  54                 } else {
  55                         d->const_used[src->Index] = 1;
  56                 }
  57         }
  58 }
  59
  60 void rc_remove_unused_constants(struct radeon_compiler *c, void *user)
  61 {
  62         unsigned **out_remap_table = (unsigned**)user;
  63         unsigned char *const_used;
  64         unsigned *remap_table;
  65         unsigned *inv_remap_table;
  66         unsigned has_rel_addr = 0;
  67         unsigned is_identity = 1;
  68         unsigned are_externals_remapped = 0;
  69         struct rc_constant *constants = c->Program.Constants.Constants;
  70         struct mark_used_data d;
  71         unsigned new_count;
  72
  73         if (!c->Program.Constants.Count) {
  74                 *out_remap_table = NULL;
  75                 return;
  76         }
  77
  78         const_used = malloc(c->Program.Constants.Count);
  79         memset(const_used, 0, c->Program.Constants.Count);
  80
  81         d.const_used = const_used;
  82         d.has_rel_addr = &has_rel_addr;
  83
  84         /* Pass 1: Mark used constants. */
  85         for (struct rc_instruction *inst = c->Program.Instructions.Next;
  86              inst != &c->Program.Instructions; inst = inst->Next) {
  87                 rc_for_all_reads_src(inst, mark_used, &d);
  88         }
  89
  90         /* Pass 2: If there is relative addressing or dead constant elimination
  91          * is disabled, mark all externals as used. */
  92         if (has_rel_addr || !c->remove_unused_constants) {
  93                 for (unsigned i = 0; i < c->Program.Constants.Count; i++)
  94                         if (constants[i].Type == RC_CONSTANT_EXTERNAL)
  95                                 const_used[i] = 1;
  96         }
  97
  98         /* Pass 3: Make the remapping table and remap constants.
  99          * This pass removes unused constants simply by overwriting them by other constants. */
 100         remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
 101         inv_remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
 102         new_count = 0;
 103
 104         for (unsigned i = 0; i < c->Program.Constants.Count; i++) {
 105                 if (const_used[i]) {
 106                         remap_table[new_count] = i;
 107                         inv_remap_table[i] = new_count;
 108
 109                         if (i != new_count) {
 110                                 if (constants[i].Type == RC_CONSTANT_EXTERNAL)
 111                                         are_externals_remapped = 1;
 112
 113                                 constants[new_count] = constants[i];
 114                                 is_identity = 0;
 115                         }
 116                         new_count++;
 117                 }
 118         }
 119
 120         /*  is_identity ==> new_count == old_count
 121          * !is_identity ==> new_count <  old_count */
 122         assert( is_identity || new_count <  c->Program.Constants.Count);
 123         assert(!((has_rel_addr || !c->remove_unused_constants) && are_externals_remapped));
 124
 125         /* Pass 4: Redirect reads of all constants to their new locations. */
 126         if (!is_identity) {
 127                 for (struct rc_instruction *inst = c->Program.Instructions.Next;
 128                      inst != &c->Program.Instructions; inst = inst->Next) {
 129                         rc_remap_registers(inst, remap_regs, inv_remap_table);
 130                 }
 131         }
 132
 133         /* Set the new constant count. Note that new_count may be less than
 134          * Count even though the remapping function is identity. In that case,
 135          * the constants have been removed at the end of the array. */
 136         c->Program.Constants.Count = new_count;
 137
 138         if (are_externals_remapped) {
 139                 *out_remap_table = remap_table;
 140         } else {
 141                 *out_remap_table = NULL;
 142                 free(remap_table);
 143         }
 144
 145         free(const_used);
 146         free(inv_remap_table);
 147
 148         if (c->Debug & RC_DBG_LOG)
 149                 rc_constants_print(&c->Program.Constants);
 150 }