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      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 bool
     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 false;
     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       nir_tex_instr_add_src(instr, nir_tex_src_texture_offset,
    113                             nir_src_for_ssa(indirect));
    114       nir_tex_instr_add_src(instr, nir_tex_src_sampler_offset,
    115                             nir_src_for_ssa(indirect));
    116 
    117       instr->texture_array_size = array_elements;
    118    }
    119 
    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 
    130    return true;
    131 }
    132 
    133 static bool
    134 lower_impl(nir_function_impl *impl, const struct gl_shader_program *shader_program,
    135            gl_shader_stage stage)
    136 {
    137    nir_builder b;
    138    nir_builder_init(&b, impl);
    139    bool progress = false;
    140 
    141    nir_foreach_block(block, impl) {
    142       nir_foreach_instr(instr, block) {
    143          if (instr->type == nir_instr_type_tex)
    144             progress |= lower_sampler(nir_instr_as_tex(instr),
    145                                       shader_program, stage, &b);
    146       }
    147    }
    148 
    149    return progress;
    150 }
    151 
    152 bool
    153 nir_lower_samplers(nir_shader *shader,
    154                    const struct gl_shader_program *shader_program)
    155 {
    156    bool progress = false;
    157 
    158    nir_foreach_function(function, shader) {
    159       if (function->impl)
    160          progress |= lower_impl(function->impl, shader_program,
    161                                 shader->info.stage);
    162    }
    163 
    164    return progress;
    165 }
    166