src/glsl/nir/nir_lower_samplers.cpp

   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 "../program.h"
  28 #include "program/hash_table.h"
  29 #include "ir_uniform.h"
  30
  31 extern "C" {
  32 #include "main/compiler.h"
  33 #include "main/mtypes.h"
  34 #include "program/prog_parameter.h"
  35 #include "program/program.h"
  36 }
  37
  38 static unsigned
  39 get_deref_name_offset(nir_deref_var *deref_var,
  40                       gl_shader_program *shader_program, char **name,
  41                       void *mem_ctx)
  42 {
  43    nir_deref *deref = &deref_var->deref;
  44    nir_deref_array *deref_array;
  45    nir_deref_struct *deref_struct;
  46
  47    *name = ralloc_strdup(mem_ctx, deref_var->var->name);
  48
  49    while (deref->child != NULL) {
  50       switch (deref->child->deref_type) {
  51       case nir_deref_type_array:
  52          deref_array = nir_deref_as_array(deref->child);
  53          if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
  54             /* GLSL 1.10 and 1.20 allowed variable sampler array indices,
  55              * while GLSL 1.30 requires that the array indices be
  56              * constant integer expressions.  We don't expect any driver
  57              * to actually work with a really variable array index, so
  58              * all that would work would be an unrolled loop counter that
  59              * ends up being constant.
  60              */
  61             ralloc_strcat(&shader_program->InfoLog,
  62                         "warning: Variable sampler array index unsupported.\n"
  63                         "This feature of the language was removed in GLSL 1.20 "
  64                         "and is unlikely to be supported for 1.10 in Mesa.\n");
  65          }
  66          if (deref_array->deref.child == NULL) {
  67             return deref_array->base_offset;
  68          }
  69          ralloc_asprintf_append(name, "[%u]", deref_array->base_offset);
  70          break;
  71
  72       case nir_deref_type_struct: {
  73          deref_struct = nir_deref_as_struct(deref->child);
  74          const char *field = glsl_get_struct_elem_name(deref->type,
  75                                                        deref_struct->index);
  76          ralloc_asprintf_append(name, ".%s", field);
  77          break;
  78       }
  79
  80       default:
  81          assert(0);
  82          break;
  83       }
  84       deref = deref->child;
  85    }
  86
  87    return 0;
  88 }
  89
  90 static unsigned
  91 get_sampler_index(nir_deref_var *sampler,
  92                   struct gl_shader_program *shader_program,
  93                   const struct gl_program *prog)
  94 {
  95    void *mem_ctx = ralloc_context(NULL);
  96    char *name;
  97    unsigned offset = get_deref_name_offset(sampler, shader_program, &name,
  98                                            mem_ctx);
  99
 100    GLuint shader = _mesa_program_enum_to_shader_stage(prog->Target);
 101
 102    unsigned location;
 103    if (!shader_program->UniformHash->get(location, name)) {
 104       linker_error(shader_program,
 105                    "failed to find sampler named %s.\n", name);
 106       return 0;
 107    }
 108
 109    if (!shader_program->UniformStorage[location].sampler[shader].active) {
 110       assert(0 && "cannot return a sampler");
 111       linker_error(shader_program,
 112                    "cannot return a sampler named %s, because it is not "
 113                    "used in this shader stage. This is a driver bug.\n",
 114                    name);
 115       return 0;
 116    }
 117
 118    ralloc_free(mem_ctx);
 119
 120    return shader_program->UniformStorage[location].sampler[shader].index +
 121           offset;
 122 }
 123
 124 static void
 125 lower_sampler(nir_tex_instr *instr, struct gl_shader_program *shader_program,
 126               const struct gl_program *prog)
 127 {
 128    if (instr->sampler) {
 129       instr->sampler_index = get_sampler_index(instr->sampler, shader_program,
 130                                                prog);
 131       nir_src empty_src;
 132       memset(&empty_src, 0, sizeof empty_src);
 133       for (nir_deref *deref = &instr->sampler->deref; deref; deref = deref->child) {
 134          if (deref->deref_type == nir_deref_type_array) {
 135             nir_deref_array *arr = nir_deref_as_array(deref);
 136             nir_instr_rewrite_src(&instr->instr, &arr->indirect, empty_src);
 137          }
 138       }
 139
 140       instr->sampler = NULL;
 141    }
 142 }
 143
 144 typedef struct {
 145    struct gl_shader_program *shader_program;
 146    struct gl_program *prog;
 147 } lower_state;
 148
 149 static bool
 150 lower_block_cb(nir_block *block, void *_state)
 151 {
 152    lower_state *state = (lower_state *) _state;
 153
 154    nir_foreach_instr(block, instr) {
 155       if (instr->type == nir_instr_type_tex) {
 156          nir_tex_instr *tex_instr = nir_instr_as_tex(instr);
 157          lower_sampler(tex_instr, state->shader_program, state->prog);
 158       }
 159    }
 160
 161    return true;
 162 }
 163
 164 static void
 165 lower_impl(nir_function_impl *impl, struct gl_shader_program *shader_program,
 166            struct gl_program *prog)
 167 {
 168    lower_state state;
 169    state.shader_program = shader_program;
 170    state.prog = prog;
 171    nir_foreach_block(impl, lower_block_cb, &state);
 172 }
 173
 174 extern "C" void
 175 nir_lower_samplers(nir_shader *shader, struct gl_shader_program *shader_program,
 176                    struct gl_program *prog)
 177 {
 178    nir_foreach_overload(shader, overload) {
 179       if (overload->impl)
 180          lower_impl(overload->impl, shader_program, prog);
 181    }
 182 }