src/panfrost/bifrost/bi_ra.c

   1 /*
   2  * Copyright (C) 2020 Collabora Ltd.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  *
  23  * Authors (Collabora):
  24  *      Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
  25  */
  26
  27 #include "compiler.h"
  28 #include "panfrost/util/lcra.h"
  29 #include "util/u_memory.h"
  30
  31 static void
  32 bi_compute_interference(bi_context *ctx, struct lcra_state *l)
  33 {
  34         bi_compute_liveness(ctx);
  35
  36         bi_foreach_block(ctx, _blk) {
  37                 bi_block *blk = (bi_block *) _blk;
  38                 uint16_t *live = mem_dup(_blk->live_out, l->node_count * sizeof(uint16_t));
  39
  40                 bi_foreach_instr_in_block_rev(blk, ins) {
  41                         /* Mark all registers live after the instruction as
  42                          * interfering with the destination */
  43
  44                         if (ins->dest && (ins->dest < l->node_count)) {
  45                                 for (unsigned i = 1; i < l->node_count; ++i) {
  46                                         if (live[i])
  47                                                 lcra_add_node_interference(l, ins->dest, ins->writemask, i, live[i]);
  48                                 }
  49                         }
  50
  51                         /* Update live_in */
  52                         bi_liveness_ins_update(live, ins, l->node_count);
  53                 }
  54
  55                 free(live);
  56         }
  57 }
  58
  59 enum {
  60         BI_REG_CLASS_WORK = 0,
  61 } bi_reg_class;
  62
  63 static struct lcra_state *
  64 bi_allocate_registers(bi_context *ctx, bool *success)
  65 {
  66         unsigned node_count = bi_max_temp(ctx);
  67
  68         struct lcra_state *l =
  69                 lcra_alloc_equations(node_count, 1, 8, 16, 1);
  70
  71         l->class_start[BI_REG_CLASS_WORK] = 0;
  72         l->class_size[BI_REG_CLASS_WORK] = 64 * 4; /* R0 - R63, all 32-bit */
  73
  74         bi_foreach_instr_global(ctx, ins) {
  75                 unsigned dest = ins->dest;
  76
  77                 if (!dest || (dest >= node_count))
  78                         continue;
  79
  80                 l->class[dest] = BI_REG_CLASS_WORK;
  81                 lcra_set_alignment(l, dest, 2); /* 2^2 = 4 */
  82                 lcra_restrict_range(l, dest, 4);
  83         }
  84
  85         bi_compute_interference(ctx, l);
  86
  87         *success = lcra_solve(l);
  88
  89         return l;
  90 }
  91
  92 void
  93 bi_register_allocate(bi_context *ctx)
  94 {
  95         struct lcra_state *l = NULL;
  96         bool success = false;
  97
  98         do {
  99                 if (l) {
 100                         lcra_free(l);
 101                         l = NULL;
 102                 }
 103
 104                 bi_invalidate_liveness(ctx);
 105                 l = bi_allocate_registers(ctx, &success);
 106
 107                 /* TODO: Spilling */
 108                 assert(success);
 109         } while(!success);
 110
 111         lcra_free(l);
 112 }