src/compiler/nir/nir_lower_uniforms_to_ubo.c

   1 /*
   2  * Copyright 2017 Advanced Micro Devices, Inc.
   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  * on the rights to use, copy, modify, merge, publish, distribute, sub
   8  * license, and/or sell copies of the Software, and to permit persons to whom
   9  * the 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 NON-INFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
  19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  21  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /*
  25  * Remap load_uniform intrinsics to UBO accesses of UBO binding point 0.
  26  * Simultaneously, remap existing UBO accesses by increasing their binding
  27  * point by 1.
  28  *
  29  * Both the base and the offset are interpreted as 16-byte units.
  30  *
  31  * Note that locations can be set in different units, and the multiplier
  32  * argument caters to supporting these different units.
  33  * For example:
  34  * - st_glsl_to_nir uses dwords (4 bytes) so the multiplier should be 4
  35  * - tgsi_to_nir uses bytes, so the multiplier should be 16
  36  */
  37
  38 #include "nir.h"
  39 #include "nir_builder.h"
  40
  41 static bool
  42 lower_instr(nir_intrinsic_instr *instr, nir_builder *b, int multiplier)
  43 {
  44    b->cursor = nir_before_instr(&instr->instr);
  45
  46    /* Increase all UBO binding points by 1. */
  47    if (instr->intrinsic == nir_intrinsic_load_ubo &&
  48        !b->shader->info.first_ubo_is_default_ubo) {
  49       nir_ssa_def *old_idx = nir_ssa_for_src(b, instr->src[0], 1);
  50       nir_ssa_def *new_idx = nir_iadd(b, old_idx, nir_imm_int(b, 1));
  51       nir_instr_rewrite_src(&instr->instr, &instr->src[0],
  52                             nir_src_for_ssa(new_idx));
  53       return true;
  54    }
  55
  56    if (instr->intrinsic == nir_intrinsic_load_uniform) {
  57       nir_ssa_def *ubo_idx = nir_imm_int(b, 0);
  58       nir_ssa_def *ubo_offset =
  59          nir_iadd(b, nir_imm_int(b, multiplier * nir_intrinsic_base(instr)),
  60                   nir_imul(b, nir_imm_int(b, multiplier),
  61                            nir_ssa_for_src(b, instr->src[0], 1)));
  62
  63       nir_intrinsic_instr *load =
  64          nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_ubo);
  65       load->num_components = instr->num_components;
  66       load->src[0] = nir_src_for_ssa(ubo_idx);
  67       load->src[1] = nir_src_for_ssa(ubo_offset);
  68       nir_ssa_dest_init(&load->instr, &load->dest,
  69                         load->num_components, instr->dest.ssa.bit_size,
  70                         instr->dest.ssa.name);
  71       nir_builder_instr_insert(b, &load->instr);
  72       nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(&load->dest.ssa));
  73
  74       nir_instr_remove(&instr->instr);
  75       return true;
  76    }
  77
  78    return false;
  79 }
  80
  81 bool
  82 nir_lower_uniforms_to_ubo(nir_shader *shader, int multiplier)
  83 {
  84    bool progress = false;
  85
  86    nir_foreach_function(function, shader) {
  87       if (function->impl) {
  88          nir_builder builder;
  89          nir_builder_init(&builder, function->impl);
  90          nir_foreach_block(block, function->impl) {
  91             nir_foreach_instr_safe(instr, block) {
  92                if (instr->type == nir_instr_type_intrinsic)
  93                   progress |= lower_instr(nir_instr_as_intrinsic(instr),
  94                                           &builder,
  95                                           multiplier);
  96             }
  97          }
  98
  99          nir_metadata_preserve(function->impl, nir_metadata_block_index |
 100                                                nir_metadata_dominance);
 101       }
 102    }
 103
 104    shader->info.first_ubo_is_default_ubo = true;
 105    return progress;
 106 }
 107
 108