src/compiler/nir/nir_lower_input_attachments.c

   1 /*
   2  * Copyright © 2016 Intel Corporation
   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
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include "nir.h"
  25 #include "nir_builder.h"
  26
  27 static nir_ssa_def *
  28 load_frag_coord(const nir_input_attachment_options *options, nir_builder *b)
  29 {
  30    if (options->use_fragcoord_sysval)
  31       return nir_load_frag_coord(b);
  32
  33    nir_variable *pos =
  34       nir_find_variable_with_location(b->shader, nir_var_shader_in,
  35                                       VARYING_SLOT_POS);
  36    if (pos == NULL) {
  37       pos = nir_variable_create(b->shader, nir_var_shader_in,
  38                                 glsl_vec4_type(), NULL);
  39       pos->data.location = VARYING_SLOT_POS;
  40    }
  41    /**
  42     * From Vulkan spec:
  43     *   "The OriginLowerLeft execution mode must not be used; fragment entry
  44     *    points must declare OriginUpperLeft."
  45     *
  46     * So at this point origin_upper_left should be true
  47     */
  48    assert(b->shader->info.fs.origin_upper_left == true);
  49
  50    return nir_load_var(b, pos);
  51 }
  52
  53 static nir_ssa_def *
  54 load_layer_id(const nir_input_attachment_options *options, nir_builder *b)
  55 {
  56    if (options->use_layer_id_sysval) {
  57       if (options->use_view_id_for_layer)
  58          return nir_load_view_index(b);
  59       else
  60          return nir_load_layer_id(b);
  61    }
  62
  63    gl_varying_slot slot = options->use_view_id_for_layer ?
  64       VARYING_SLOT_VIEW_INDEX : VARYING_SLOT_LAYER;
  65    nir_variable *layer_id =
  66       nir_find_variable_with_location(b->shader, nir_var_shader_in, slot);
  67
  68    if (layer_id == NULL) {
  69       layer_id = nir_variable_create(b->shader, nir_var_shader_in,
  70                                      glsl_int_type(), NULL);
  71       layer_id->data.location = slot;
  72       layer_id->data.interpolation = INTERP_MODE_FLAT;
  73       layer_id->data.driver_location = b->shader->num_inputs++;
  74    }
  75
  76    return nir_load_var(b, layer_id);
  77 }
  78
  79 static bool
  80 try_lower_input_load(nir_function_impl *impl, nir_intrinsic_instr *load,
  81                      const nir_input_attachment_options *options)
  82 {
  83    nir_deref_instr *deref = nir_src_as_deref(load->src[0]);
  84    assert(glsl_type_is_image(deref->type));
  85
  86    enum glsl_sampler_dim image_dim = glsl_get_sampler_dim(deref->type);
  87    if (image_dim != GLSL_SAMPLER_DIM_SUBPASS &&
  88        image_dim != GLSL_SAMPLER_DIM_SUBPASS_MS)
  89       return false;
  90
  91    const bool multisampled = (image_dim == GLSL_SAMPLER_DIM_SUBPASS_MS);
  92
  93    nir_builder b;
  94    nir_builder_init(&b, impl);
  95    b.cursor = nir_instr_remove(&load->instr);
  96
  97    nir_ssa_def *frag_coord = load_frag_coord(options, &b);
  98    frag_coord = nir_f2i32(&b, frag_coord);
  99    nir_ssa_def *offset = nir_ssa_for_src(&b, load->src[1], 2);
 100    nir_ssa_def *pos = nir_iadd(&b, frag_coord, offset);
 101
 102    nir_ssa_def *layer = load_layer_id(options, &b);
 103    nir_ssa_def *coord =
 104       nir_vec3(&b, nir_channel(&b, pos, 0), nir_channel(&b, pos, 1), layer);
 105
 106    nir_tex_instr *tex = nir_tex_instr_create(b.shader, 3 + multisampled);
 107
 108    tex->op = nir_texop_txf;
 109    tex->sampler_dim = image_dim;
 110
 111    switch (glsl_get_sampler_result_type(deref->type)) {
 112    case GLSL_TYPE_FLOAT:
 113       tex->dest_type = nir_type_float;
 114       break;
 115    case GLSL_TYPE_INT:
 116       tex->dest_type = nir_type_int;
 117       break;
 118    case GLSL_TYPE_UINT:
 119       tex->dest_type = nir_type_uint;
 120       break;
 121    default:
 122       unreachable("Invalid image type");
 123    }
 124    tex->is_array = true;
 125    tex->is_shadow = false;
 126
 127    tex->texture_index = 0;
 128    tex->sampler_index = 0;
 129
 130    tex->src[0].src_type = nir_tex_src_texture_deref;
 131    tex->src[0].src = nir_src_for_ssa(&deref->dest.ssa);
 132
 133    tex->src[1].src_type = nir_tex_src_coord;
 134    tex->src[1].src = nir_src_for_ssa(coord);
 135    tex->coord_components = 3;
 136
 137    tex->src[2].src_type = nir_tex_src_lod;
 138    tex->src[2].src = nir_src_for_ssa(nir_imm_int(&b, 0));
 139
 140    if (image_dim == GLSL_SAMPLER_DIM_SUBPASS_MS) {
 141       tex->op = nir_texop_txf_ms;
 142       tex->src[3].src_type = nir_tex_src_ms_index;
 143       tex->src[3].src = load->src[2];
 144    }
 145
 146    tex->texture_non_uniform = nir_intrinsic_access(load) & ACCESS_NON_UNIFORM;
 147
 148    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 149    nir_builder_instr_insert(&b, &tex->instr);
 150
 151    nir_ssa_def_rewrite_uses(&load->dest.ssa,
 152                             nir_src_for_ssa(&tex->dest.ssa));
 153
 154    return true;
 155 }
 156
 157 static bool
 158 try_lower_input_texop(nir_function_impl *impl, nir_tex_instr *tex,
 159                       const nir_input_attachment_options *options)
 160 {
 161    nir_deref_instr *deref = nir_src_as_deref(tex->src[0].src);
 162
 163    if (glsl_get_sampler_dim(deref->type) != GLSL_SAMPLER_DIM_SUBPASS_MS)
 164       return false;
 165
 166    nir_builder b;
 167    nir_builder_init(&b, impl);
 168    b.cursor = nir_before_instr(&tex->instr);
 169
 170    nir_ssa_def *frag_coord = load_frag_coord(options, &b);
 171    frag_coord = nir_f2i32(&b, frag_coord);
 172
 173    nir_ssa_def *layer = load_layer_id(options, &b);
 174    nir_ssa_def *coord = nir_vec3(&b, nir_channel(&b, frag_coord, 0),
 175                                      nir_channel(&b, frag_coord, 1), layer);
 176
 177    tex->coord_components = 3;
 178
 179    nir_instr_rewrite_src(&tex->instr, &tex->src[1].src, nir_src_for_ssa(coord));
 180
 181    return true;
 182 }
 183
 184 bool
 185 nir_lower_input_attachments(nir_shader *shader,
 186                             const nir_input_attachment_options *options)
 187 {
 188    assert(shader->info.stage == MESA_SHADER_FRAGMENT);
 189    bool progress = false;
 190
 191    nir_foreach_function(function, shader) {
 192       if (!function->impl)
 193          continue;
 194
 195       nir_foreach_block(block, function->impl) {
 196          nir_foreach_instr_safe(instr, block) {
 197             switch (instr->type) {
 198             case nir_instr_type_tex: {
 199                nir_tex_instr *tex = nir_instr_as_tex(instr);
 200
 201                if (tex->op == nir_texop_fragment_mask_fetch ||
 202                    tex->op == nir_texop_fragment_fetch) {
 203                   progress |= try_lower_input_texop(function->impl, tex,
 204                                                     options);
 205                }
 206                break;
 207             }
 208             case nir_instr_type_intrinsic: {
 209                nir_intrinsic_instr *load = nir_instr_as_intrinsic(instr);
 210
 211                if (load->intrinsic == nir_intrinsic_image_deref_load) {
 212                   progress |= try_lower_input_load(function->impl, load,
 213                                                    options);
 214                }
 215                break;
 216             }
 217             default:
 218                break;
 219             }
 220          }
 221       }
 222    }
 223
 224    return progress;
 225 }