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_builder *b, nir_ssa_def *ptr,
  39                      const struct gl_shader_program *shader_program,
  40                      unsigned *base_index, nir_ssa_def **index,
  41                      unsigned *array_elements)
  42 {
  43    *base_index = 0;
  44    *index = NULL;
  45    *array_elements = 1;
  46    unsigned location = 0;
  47
  48    nir_deref_instr *deref = nir_instr_as_deref(ptr->parent_instr);
  49    while (deref->deref_type != nir_deref_type_var) {
  50       assert(deref->parent.is_ssa);
  51       nir_deref_instr *parent =
  52          nir_instr_as_deref(deref->parent.ssa->parent_instr);
  53
  54       switch (deref->deref_type) {
  55       case nir_deref_type_struct:
  56          location += glsl_get_record_location_offset(parent->type,
  57                                                      deref->strct.index);
  58          break;
  59
  60       case nir_deref_type_array: {
  61          nir_const_value *const_deref_index =
  62             nir_src_as_const_value(deref->arr.index);
  63
  64          if (const_deref_index && *index == NULL) {
  65             /* We're still building a direct index */
  66             *base_index += const_deref_index->u32[0] * *array_elements;
  67          } else {
  68             if (*index == NULL) {
  69                /* We used to be direct but not anymore */
  70                *index = nir_imm_int(b, *base_index);
  71                *base_index = 0;
  72             }
  73
  74             *index = nir_iadd(b, *index,
  75                      nir_imul(b, nir_imm_int(b, *array_elements),
  76                               nir_ssa_for_src(b, deref->arr.index, 1)));
  77          }
  78
  79          *array_elements *= glsl_get_length(parent->type);
  80          break;
  81       }
  82
  83       default:
  84          unreachable("Invalid sampler deref type");
  85       }
  86
  87       deref = parent;
  88    }
  89
  90    if (*index)
  91       *index = nir_umin(b, *index, nir_imm_int(b, *array_elements - 1));
  92
  93    /* We hit the deref_var.  This is the end of the line */
  94    assert(deref->deref_type == nir_deref_type_var);
  95
  96    location += deref->var->data.location;
  97
  98    gl_shader_stage stage = b->shader->info.stage;
  99    assert(location < shader_program->data->NumUniformStorage &&
 100           shader_program->data->UniformStorage[location].opaque[stage].active);
 101
 102    *base_index +=
 103       shader_program->data->UniformStorage[location].opaque[stage].index;
 104 }
 105
 106 static bool
 107 lower_sampler(nir_builder *b, nir_tex_instr *instr,
 108               const struct gl_shader_program *shader_program)
 109 {
 110    int texture_idx =
 111       nir_tex_instr_src_index(instr, nir_tex_src_texture_deref);
 112    int sampler_idx =
 113       nir_tex_instr_src_index(instr, nir_tex_src_sampler_deref);
 114
 115    if (texture_idx < 0)
 116       return false;
 117
 118    assert(texture_idx >= 0 && sampler_idx >= 0);
 119    assert(instr->src[texture_idx].src.is_ssa);
 120    assert(instr->src[sampler_idx].src.is_ssa);
 121    assert(instr->src[texture_idx].src.ssa == instr->src[sampler_idx].src.ssa);
 122
 123    b->cursor = nir_before_instr(&instr->instr);
 124
 125    unsigned base_offset, array_elements;
 126    nir_ssa_def *indirect;
 127    calc_sampler_offsets(b, instr->src[texture_idx].src.ssa, shader_program,
 128                         &base_offset, &indirect, &array_elements);
 129
 130    instr->texture_index = base_offset;
 131    instr->sampler_index = base_offset;
 132    if (indirect) {
 133       nir_instr_rewrite_src(&instr->instr, &instr->src[texture_idx].src,
 134                             nir_src_for_ssa(indirect));
 135       instr->src[texture_idx].src_type = nir_tex_src_texture_offset;
 136       nir_instr_rewrite_src(&instr->instr, &instr->src[sampler_idx].src,
 137                             nir_src_for_ssa(indirect));
 138       instr->src[sampler_idx].src_type = nir_tex_src_sampler_offset;
 139
 140       instr->texture_array_size = array_elements;
 141    } else {
 142       nir_tex_instr_remove_src(instr, texture_idx);
 143       /* The sampler index may have changed */
 144       sampler_idx = nir_tex_instr_src_index(instr, nir_tex_src_sampler_deref);
 145       nir_tex_instr_remove_src(instr, sampler_idx);
 146    }
 147
 148    return true;
 149 }
 150
 151 static bool
 152 lower_impl(nir_function_impl *impl,
 153            const struct gl_shader_program *shader_program)
 154 {
 155    nir_builder b;
 156    nir_builder_init(&b, impl);
 157    bool progress = false;
 158
 159    nir_foreach_block(block, impl) {
 160       nir_foreach_instr(instr, block) {
 161          if (instr->type == nir_instr_type_tex)
 162             progress |= lower_sampler(&b, nir_instr_as_tex(instr),
 163                                       shader_program);
 164       }
 165    }
 166
 167    return progress;
 168 }
 169
 170 bool
 171 gl_nir_lower_samplers(nir_shader *shader,
 172                       const struct gl_shader_program *shader_program)
 173 {
 174    bool progress = false;
 175
 176    nir_foreach_function(function, shader) {
 177       if (function->impl)
 178          progress |= lower_impl(function->impl, shader_program);
 179    }
 180
 181    return progress;
 182 }