src/compiler/glsl/gl_nir_lower_samplers.c

   1 /*
   2  * Copyright (C) 2005-2007  Brian Paul   All Rights Reserved.
   3  * Copyright (C) 2008  VMware, Inc.   All Rights Reserved.
   4  * Copyright © 2014 Intel Corporation
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 #include "compiler/nir/nir.h"
  27 #include "compiler/nir/nir_builder.h"
  28 #include "gl_nir.h"
  29 #include "ir_uniform.h"
  30
  31 #include "main/compiler.h"
  32 #include "main/mtypes.h"
  33
  34 /* Calculate the sampler index based on array indicies and also
  35  * calculate the base uniform location for struct members.
  36  */
  37 static void
  38 calc_sampler_offsets(nir_deref *tail, nir_tex_instr *instr,
  39                      unsigned *array_elements, nir_ssa_def **indirect,
  40                      nir_builder *b, unsigned *location)
  41 {
  42    if (tail->child == NULL)
  43       return;
  44
  45    switch (tail->child->deref_type) {
  46    case nir_deref_type_array: {
  47       nir_deref_array *deref_array = nir_deref_as_array(tail->child);
  48
  49       assert(deref_array->deref_array_type != nir_deref_array_type_wildcard);
  50
  51       calc_sampler_offsets(tail->child, instr, array_elements,
  52                            indirect, b, location);
  53       instr->texture_index += deref_array->base_offset * *array_elements;
  54
  55       if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
  56          nir_ssa_def *mul =
  57             nir_imul(b, nir_imm_int(b, *array_elements),
  58                      nir_ssa_for_src(b, deref_array->indirect, 1));
  59
  60          nir_instr_rewrite_src(&instr->instr, &deref_array->indirect,
  61                                NIR_SRC_INIT);
  62
  63          if (*indirect) {
  64             *indirect = nir_iadd(b, *indirect, mul);
  65          } else {
  66             *indirect = mul;
  67          }
  68       }
  69
  70       *array_elements *= glsl_get_length(tail->type);
  71        break;
  72    }
  73
  74    case nir_deref_type_struct: {
  75       nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
  76       *location += glsl_get_record_location_offset(tail->type, deref_struct->index);
  77       calc_sampler_offsets(tail->child, instr, array_elements,
  78                            indirect, b, location);
  79       break;
  80    }
  81
  82    default:
  83       unreachable("Invalid deref type");
  84       break;
  85    }
  86 }
  87
  88 static bool
  89 lower_sampler(nir_builder *b, nir_tex_instr *instr,
  90               const struct gl_shader_program *shader_program)
  91 {
  92    if (instr->texture == NULL)
  93       return false;
  94
  95    /* In GLSL, we only fill out the texture field.  The sampler is inferred */
  96    assert(instr->sampler == NULL || shader_program->data->spirv);
  97
  98    instr->texture_index = 0;
  99    unsigned location = instr->texture->var->data.location;
 100    unsigned array_elements = 1;
 101    nir_ssa_def *indirect = NULL;
 102
 103    b->cursor = nir_before_instr(&instr->instr);
 104    calc_sampler_offsets(&instr->texture->deref, instr, &array_elements,
 105                         &indirect, b, &location);
 106
 107    if (indirect) {
 108       assert(array_elements >= 1);
 109       indirect = nir_umin(b, indirect, nir_imm_int(b, array_elements - 1));
 110
 111       nir_tex_instr_add_src(instr, nir_tex_src_texture_offset,
 112                             nir_src_for_ssa(indirect));
 113       nir_tex_instr_add_src(instr, nir_tex_src_sampler_offset,
 114                             nir_src_for_ssa(indirect));
 115
 116       instr->texture_array_size = array_elements;
 117    }
 118
 119    gl_shader_stage stage = b->shader->info.stage;
 120    assert(location < shader_program->data->NumUniformStorage &&
 121           shader_program->data->UniformStorage[location].opaque[stage].active);
 122
 123    instr->texture_index +=
 124       shader_program->data->UniformStorage[location].opaque[stage].index;
 125
 126    instr->sampler_index = instr->texture_index;
 127
 128    instr->texture = NULL;
 129    nir_instr_rewrite_deref(&instr->instr, &instr->sampler, NULL);
 130
 131    return true;
 132 }
 133
 134 static bool
 135 lower_impl(nir_function_impl *impl,
 136            const struct gl_shader_program *shader_program)
 137 {
 138    nir_builder b;
 139    nir_builder_init(&b, impl);
 140    bool progress = false;
 141
 142    nir_foreach_block(block, impl) {
 143       nir_foreach_instr(instr, block) {
 144          if (instr->type == nir_instr_type_tex)
 145             progress |= lower_sampler(&b, nir_instr_as_tex(instr),
 146                                       shader_program);
 147       }
 148    }
 149
 150    return progress;
 151 }
 152
 153 bool
 154 gl_nir_lower_samplers(nir_shader *shader,
 155                       const struct gl_shader_program *shader_program)
 156 {
 157    bool progress = false;
 158
 159    nir_assert_lowered_derefs(shader, nir_lower_texture_derefs);
 160
 161    nir_foreach_function(function, shader) {
 162       if (function->impl)
 163          progress |= lower_impl(function->impl, shader_program);
 164    }
 165
 166    return progress;
 167 }