src/glsl/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 "../program.h"
  29 #include "program/hash_table.h"
  30 #include "ir_uniform.h"
  31
  32 #include "main/compiler.h"
  33 #include "main/mtypes.h"
  34 #include "program/prog_parameter.h"
  35 #include "program/program.h"
  36
  37 /* Calculate the sampler index based on array indicies and also
  38  * calculate the base uniform location for struct members.
  39  */
  40 static void
  41 calc_sampler_offsets(nir_deref *tail, nir_tex_instr *instr,
  42                      unsigned *array_elements, nir_ssa_def **indirect,
  43                      nir_builder *b, unsigned *location)
  44 {
  45    if (tail->child == NULL)
  46       return;
  47
  48    switch (tail->child->deref_type) {
  49    case nir_deref_type_array: {
  50       nir_deref_array *deref_array = nir_deref_as_array(tail->child);
  51
  52       assert(deref_array->deref_array_type != nir_deref_array_type_wildcard);
  53
  54       calc_sampler_offsets(tail->child, instr, array_elements,
  55                            indirect, b, location);
  56       instr->sampler_index += deref_array->base_offset * *array_elements;
  57
  58       if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
  59          nir_ssa_def *mul =
  60             nir_imul(b, nir_imm_int(b, *array_elements),
  61                      nir_ssa_for_src(b, deref_array->indirect, 1));
  62
  63          nir_instr_rewrite_src(&instr->instr, &deref_array->indirect,
  64                                NIR_SRC_INIT);
  65
  66          if (*indirect) {
  67             *indirect = nir_iadd(b, *indirect, mul);
  68          } else {
  69             *indirect = mul;
  70          }
  71       }
  72
  73       *array_elements *= glsl_get_length(tail->type);
  74        break;
  75    }
  76
  77    case nir_deref_type_struct: {
  78       nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
  79       *location += glsl_get_record_location_offset(tail->type, deref_struct->index);
  80       calc_sampler_offsets(tail->child, instr, array_elements,
  81                            indirect, b, location);
  82       break;
  83    }
  84
  85    default:
  86       unreachable("Invalid deref type");
  87       break;
  88    }
  89 }
  90
  91 static void
  92 lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_program,
  93               gl_shader_stage stage, nir_builder *builder)
  94 {
  95    if (instr->sampler == NULL)
  96       return;
  97
  98    /* GLSL only has combined textures/samplers */
  99    assert(instr->texture == NULL);
 100
 101    instr->sampler_index = 0;
 102    unsigned location = instr->sampler->var->data.location;
 103    unsigned array_elements = 1;
 104    nir_ssa_def *indirect = NULL;
 105
 106    builder->cursor = nir_before_instr(&instr->instr);
 107    calc_sampler_offsets(&instr->sampler->deref, instr, &array_elements,
 108                         &indirect, builder, &location);
 109
 110    if (indirect) {
 111       /* First, we have to resize the array of texture sources */
 112       nir_tex_src *new_srcs = rzalloc_array(instr, nir_tex_src,
 113                                             instr->num_srcs + 2);
 114
 115       for (unsigned i = 0; i < instr->num_srcs; i++) {
 116          new_srcs[i].src_type = instr->src[i].src_type;
 117          nir_instr_move_src(&instr->instr, &new_srcs[i].src,
 118                             &instr->src[i].src);
 119       }
 120
 121       ralloc_free(instr->src);
 122       instr->src = new_srcs;
 123
 124       /* Now we can go ahead and move the source over to being a
 125        * first-class texture source.
 126        */
 127       instr->src[instr->num_srcs].src_type = nir_tex_src_texture_offset;
 128       instr->num_srcs++;
 129       nir_instr_rewrite_src(&instr->instr,
 130                             &instr->src[instr->num_srcs - 1].src,
 131                             nir_src_for_ssa(indirect));
 132
 133       instr->src[instr->num_srcs].src_type = nir_tex_src_sampler_offset;
 134       instr->num_srcs++;
 135       nir_instr_rewrite_src(&instr->instr,
 136                             &instr->src[instr->num_srcs - 1].src,
 137                             nir_src_for_ssa(indirect));
 138
 139       instr->texture_array_size = array_elements;
 140    }
 141
 142    if (location > shader_program->NumUniformStorage - 1 ||
 143        !shader_program->UniformStorage[location].opaque[stage].active) {
 144       assert(!"cannot return a sampler");
 145       return;
 146    }
 147
 148    instr->sampler_index +=
 149       shader_program->UniformStorage[location].opaque[stage].index;
 150
 151    instr->sampler = NULL;
 152
 153    instr->texture_index = instr->sampler_index;
 154 }
 155
 156 typedef struct {
 157    nir_builder builder;
 158    const struct gl_shader_program *shader_program;
 159    gl_shader_stage stage;
 160 } lower_state;
 161
 162 static bool
 163 lower_block_cb(nir_block *block, void *_state)
 164 {
 165    lower_state *state = (lower_state *) _state;
 166
 167    nir_foreach_instr(block, instr) {
 168       if (instr->type == nir_instr_type_tex) {
 169          nir_tex_instr *tex_instr = nir_instr_as_tex(instr);
 170          lower_sampler(tex_instr, state->shader_program, state->stage,
 171                        &state->builder);
 172       }
 173    }
 174
 175    return true;
 176 }
 177
 178 static void
 179 lower_impl(nir_function_impl *impl, const struct gl_shader_program *shader_program,
 180            gl_shader_stage stage)
 181 {
 182    lower_state state;
 183
 184    nir_builder_init(&state.builder, impl);
 185    state.shader_program = shader_program;
 186    state.stage = stage;
 187
 188    nir_foreach_block(impl, lower_block_cb, &state);
 189 }
 190
 191 void
 192 nir_lower_samplers(nir_shader *shader,
 193                    const struct gl_shader_program *shader_program)
 194 {
 195    nir_foreach_overload(shader, overload) {
 196       if (overload->impl)
 197          lower_impl(overload->impl, shader_program, shader->stage);
 198    }
 199 }