src/compiler/nir/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 "nir.h"
  27 #include "nir_builder.h"
  28 #include "compiler/glsl/ir_uniform.h"
  29
  30 #include "main/compiler.h"
  31 #include "main/mtypes.h"
  32 #include "program/prog_parameter.h"
  33 #include "program/program.h"
  34
  35 /* Calculate the sampler index based on array indicies and also
  36  * calculate the base uniform location for struct members.
  37  */
  38 static void
  39 calc_sampler_offsets(nir_deref *tail, nir_tex_instr *instr,
  40                      unsigned *array_elements, nir_ssa_def **indirect,
  41                      nir_builder *b, unsigned *location)
  42 {
  43    if (tail->child == NULL)
  44       return;
  45
  46    switch (tail->child->deref_type) {
  47    case nir_deref_type_array: {
  48       nir_deref_array *deref_array = nir_deref_as_array(tail->child);
  49
  50       assert(deref_array->deref_array_type != nir_deref_array_type_wildcard);
  51
  52       calc_sampler_offsets(tail->child, instr, array_elements,
  53                            indirect, b, location);
  54       instr->texture_index += deref_array->base_offset * *array_elements;
  55
  56       if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
  57          nir_ssa_def *mul =
  58             nir_imul(b, nir_imm_int(b, *array_elements),
  59                      nir_ssa_for_src(b, deref_array->indirect, 1));
  60
  61          nir_instr_rewrite_src(&instr->instr, &deref_array->indirect,
  62                                NIR_SRC_INIT);
  63
  64          if (*indirect) {
  65             *indirect = nir_iadd(b, *indirect, mul);
  66          } else {
  67             *indirect = mul;
  68          }
  69       }
  70
  71       *array_elements *= glsl_get_length(tail->type);
  72        break;
  73    }
  74
  75    case nir_deref_type_struct: {
  76       nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
  77       *location += glsl_get_record_location_offset(tail->type, deref_struct->index);
  78       calc_sampler_offsets(tail->child, instr, array_elements,
  79                            indirect, b, location);
  80       break;
  81    }
  82
  83    default:
  84       unreachable("Invalid deref type");
  85       break;
  86    }
  87 }
  88
  89 static void
  90 lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_program,
  91               gl_shader_stage stage, nir_builder *b)
  92 {
  93    if (instr->texture == NULL)
  94       return;
  95
  96    /* In GLSL, we only fill out the texture field.  The sampler is inferred */
  97    assert(instr->sampler == NULL);
  98
  99    instr->texture_index = 0;
 100    unsigned location = instr->texture->var->data.location;
 101    unsigned array_elements = 1;
 102    nir_ssa_def *indirect = NULL;
 103
 104    b->cursor = nir_before_instr(&instr->instr);
 105    calc_sampler_offsets(&instr->texture->deref, instr, &array_elements,
 106                         &indirect, b, &location);
 107
 108    if (indirect) {
 109       assert(array_elements >= 1);
 110       indirect = nir_umin(b, indirect, nir_imm_int(b, array_elements - 1));
 111
 112       /* First, we have to resize the array of texture sources */
 113       nir_tex_src *new_srcs = rzalloc_array(instr, nir_tex_src,
 114                                             instr->num_srcs + 2);
 115
 116       for (unsigned i = 0; i < instr->num_srcs; i++) {
 117          new_srcs[i].src_type = instr->src[i].src_type;
 118          nir_instr_move_src(&instr->instr, &new_srcs[i].src,
 119                             &instr->src[i].src);
 120       }
 121
 122       ralloc_free(instr->src);
 123       instr->src = new_srcs;
 124
 125       /* Now we can go ahead and move the source over to being a
 126        * first-class texture source.
 127        */
 128       instr->src[instr->num_srcs].src_type = nir_tex_src_texture_offset;
 129       instr->num_srcs++;
 130       nir_instr_rewrite_src(&instr->instr,
 131                             &instr->src[instr->num_srcs - 1].src,
 132                             nir_src_for_ssa(indirect));
 133
 134       instr->src[instr->num_srcs].src_type = nir_tex_src_sampler_offset;
 135       instr->num_srcs++;
 136       nir_instr_rewrite_src(&instr->instr,
 137                             &instr->src[instr->num_srcs - 1].src,
 138                             nir_src_for_ssa(indirect));
 139
 140       instr->texture_array_size = array_elements;
 141    }
 142
 143    if (location > shader_program->data->NumUniformStorage - 1 ||
 144        !shader_program->data->UniformStorage[location].opaque[stage].active) {
 145       assert(!"cannot return a sampler");
 146       return;
 147    }
 148
 149    instr->texture_index +=
 150       shader_program->data->UniformStorage[location].opaque[stage].index;
 151
 152    instr->sampler_index = instr->texture_index;
 153
 154    instr->texture = NULL;
 155 }
 156
 157 static void
 158 lower_impl(nir_function_impl *impl, const struct gl_shader_program *shader_program,
 159            gl_shader_stage stage)
 160 {
 161    nir_builder b;
 162    nir_builder_init(&b, impl);
 163
 164    nir_foreach_block(block, impl) {
 165       nir_foreach_instr(instr, block) {
 166          if (instr->type == nir_instr_type_tex)
 167             lower_sampler(nir_instr_as_tex(instr), shader_program, stage, &b);
 168       }
 169    }
 170 }
 171
 172 void
 173 nir_lower_samplers(nir_shader *shader,
 174                    const struct gl_shader_program *shader_program)
 175 {
 176    nir_foreach_function(function, shader) {
 177       if (function->impl)
 178          lower_impl(function->impl, shader_program, shader->stage);
 179    }
 180 }