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 static void
  35 lower_tex_src_to_offset(nir_builder *b,
  36                         nir_tex_instr *instr, unsigned src_idx,
  37                         const struct gl_shader_program *shader_program)
  38 {
  39    nir_ssa_def *index = NULL;
  40    unsigned base_index = 0;
  41    unsigned array_elements = 1;
  42    nir_tex_src *src = &instr->src[src_idx];
  43    bool is_sampler = src->src_type == nir_tex_src_sampler_deref;
  44    unsigned location = 0;
  45
  46    /* We compute first the offsets */
  47    nir_deref_instr *deref = nir_instr_as_deref(src->src.ssa->parent_instr);
  48    while (deref->deref_type != nir_deref_type_var) {
  49       assert(deref->parent.is_ssa);
  50       nir_deref_instr *parent =
  51          nir_instr_as_deref(deref->parent.ssa->parent_instr);
  52
  53       switch (deref->deref_type) {
  54       case nir_deref_type_struct:
  55          location += glsl_get_record_location_offset(parent->type,
  56                                                      deref->strct.index);
  57          break;
  58
  59       case nir_deref_type_array: {
  60          nir_const_value *const_deref_index =
  61             nir_src_as_const_value(deref->arr.index);
  62
  63          if (const_deref_index && index == NULL) {
  64             /* We're still building a direct index */
  65             base_index += const_deref_index->u32[0] * array_elements;
  66          } else {
  67             if (index == NULL) {
  68                /* We used to be direct but not anymore */
  69                index = nir_imm_int(b, base_index);
  70                base_index = 0;
  71             }
  72
  73             index = nir_iadd(b, index,
  74                              nir_imul(b, nir_imm_int(b, array_elements),
  75                                       nir_ssa_for_src(b, deref->arr.index, 1)));
  76          }
  77
  78          array_elements *= glsl_get_length(parent->type);
  79          break;
  80       }
  81
  82       default:
  83          unreachable("Invalid sampler deref type");
  84       }
  85
  86       deref = parent;
  87    }
  88
  89    if (index)
  90       index = nir_umin(b, index, nir_imm_int(b, array_elements - 1));
  91
  92    /* We hit the deref_var.  This is the end of the line */
  93    assert(deref->deref_type == nir_deref_type_var);
  94
  95    location += deref->var->data.location;
  96
  97    gl_shader_stage stage = b->shader->info.stage;
  98    assert(location < shader_program->data->NumUniformStorage &&
  99           shader_program->data->UniformStorage[location].opaque[stage].active);
 100
 101    base_index +=
 102       shader_program->data->UniformStorage[location].opaque[stage].index;
 103
 104    /* We have the offsets, we apply them, rewriting the source or removing
 105     * instr if needed
 106     */
 107    if (index) {
 108       nir_instr_rewrite_src(&instr->instr, &src->src,
 109                             nir_src_for_ssa(index));
 110
 111       src->src_type = is_sampler ?
 112          nir_tex_src_sampler_offset :
 113          nir_tex_src_texture_offset;
 114
 115       instr->texture_array_size = array_elements;
 116    } else {
 117       nir_tex_instr_remove_src(instr, src_idx);
 118    }
 119
 120    if (is_sampler) {
 121       instr->sampler_index = base_index;
 122    } else {
 123       instr->texture_index = base_index;
 124       instr->texture_array_size = array_elements;
 125    }
 126 }
 127
 128 static bool
 129 lower_sampler(nir_builder *b, nir_tex_instr *instr,
 130               const struct gl_shader_program *shader_program)
 131 {
 132    int texture_idx =
 133       nir_tex_instr_src_index(instr, nir_tex_src_texture_deref);
 134
 135    if (texture_idx >= 0) {
 136       b->cursor = nir_before_instr(&instr->instr);
 137
 138       lower_tex_src_to_offset(b, instr, texture_idx,
 139                               shader_program);
 140    }
 141
 142    int sampler_idx =
 143       nir_tex_instr_src_index(instr, nir_tex_src_sampler_deref);
 144
 145    if (sampler_idx >= 0) {
 146       lower_tex_src_to_offset(b, instr, sampler_idx,
 147                               shader_program);
 148    }
 149
 150    if (texture_idx < 0 && sampler_idx < 0)
 151       return false;
 152
 153    return true;
 154 }
 155
 156 static bool
 157 lower_impl(nir_function_impl *impl,
 158            const struct gl_shader_program *shader_program)
 159 {
 160    nir_builder b;
 161    nir_builder_init(&b, impl);
 162    bool progress = false;
 163
 164    nir_foreach_block(block, impl) {
 165       nir_foreach_instr(instr, block) {
 166          if (instr->type == nir_instr_type_tex)
 167             progress |= lower_sampler(&b, nir_instr_as_tex(instr),
 168                                       shader_program);
 169       }
 170    }
 171
 172    return progress;
 173 }
 174
 175 bool
 176 gl_nir_lower_samplers(nir_shader *shader,
 177                       const struct gl_shader_program *shader_program)
 178 {
 179    bool progress = false;
 180
 181    nir_foreach_function(function, shader) {
 182       if (function->impl)
 183          progress |= lower_impl(function->impl, shader_program);
 184    }
 185
 186    return progress;
 187 }