src/glsl/nir/nir_lower_io.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Connor Abbott (cwabbott0@gmail.com)
  25  *    Jason Ekstrand (jason@jlekstrand.net)
  26  *
  27  */
  28
  29 /*
  30  * This lowering pass converts references to input/output variables with
  31  * loads/stores to actual input/output intrinsics.
  32  *
  33  * NOTE: This pass really only works for scalar backends at the moment due
  34  * to the way it packes the input/output data.
  35  */
  36
  37 #include "nir.h"
  38
  39 struct lower_io_state {
  40    void *mem_ctx;
  41 };
  42
  43 static unsigned
  44 type_size(const struct glsl_type *type)
  45 {
  46    unsigned int size, i;
  47
  48    switch (glsl_get_base_type(type)) {
  49    case GLSL_TYPE_UINT:
  50    case GLSL_TYPE_INT:
  51    case GLSL_TYPE_FLOAT:
  52    case GLSL_TYPE_BOOL:
  53       return glsl_get_components(type);
  54    case GLSL_TYPE_ARRAY:
  55       return type_size(glsl_get_array_element(type)) * glsl_get_length(type);
  56    case GLSL_TYPE_STRUCT:
  57       size = 0;
  58       for (i = 0; i < glsl_get_length(type); i++) {
  59          size += type_size(glsl_get_struct_field(type, i));
  60       }
  61       return size;
  62    case GLSL_TYPE_SAMPLER:
  63       return 0;
  64    case GLSL_TYPE_ATOMIC_UINT:
  65       return 0;
  66    case GLSL_TYPE_INTERFACE:
  67       return 0;
  68    case GLSL_TYPE_IMAGE:
  69       return 0;
  70    case GLSL_TYPE_VOID:
  71    case GLSL_TYPE_ERROR:
  72    case GLSL_TYPE_DOUBLE:
  73       unreachable("not reached");
  74    }
  75
  76    return 0;
  77 }
  78
  79 void
  80 nir_assign_var_locations_scalar(struct exec_list *var_list, unsigned *size)
  81 {
  82    unsigned location = 0;
  83
  84    foreach_list_typed(nir_variable, var, node, var_list) {
  85       /*
  86        * UBO's have their own address spaces, so don't count them towards the
  87        * number of global uniforms
  88        */
  89       if (var->data.mode == nir_var_uniform && var->interface_type != NULL)
  90          continue;
  91
  92       var->data.driver_location = location;
  93       location += type_size(var->type);
  94    }
  95
  96    *size = location;
  97 }
  98
  99 static bool
 100 deref_has_indirect(nir_deref_var *deref)
 101 {
 102    for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {
 103       if (tail->deref_type == nir_deref_type_array) {
 104          nir_deref_array *arr = nir_deref_as_array(tail);
 105          if (arr->deref_array_type == nir_deref_array_type_indirect)
 106             return true;
 107       }
 108    }
 109
 110    return false;
 111 }
 112
 113 static bool
 114 mark_indirect_uses_block(nir_block *block, void *void_state)
 115 {
 116    struct set *indirect_set = void_state;
 117
 118    nir_foreach_instr(block, instr) {
 119       if (instr->type != nir_instr_type_intrinsic)
 120          continue;
 121
 122       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
 123
 124       for (unsigned i = 0;
 125            i < nir_intrinsic_infos[intrin->intrinsic].num_variables; i++) {
 126          if (deref_has_indirect(intrin->variables[i]))
 127             _mesa_set_add(indirect_set, intrin->variables[i]->var);
 128       }
 129    }
 130
 131    return true;
 132 }
 133
 134 /* Identical to nir_assign_var_locations_packed except that it assigns
 135  * locations to the variables that are used 100% directly first and then
 136  * assigns locations to variables that are used indirectly.
 137  */
 138 void
 139 nir_assign_var_locations_scalar_direct_first(nir_shader *shader,
 140                                              struct exec_list *var_list,
 141                                              unsigned *direct_size,
 142                                              unsigned *size)
 143 {
 144    struct set *indirect_set = _mesa_set_create(NULL, _mesa_hash_pointer,
 145                                                _mesa_key_pointer_equal);
 146
 147    nir_foreach_overload(shader, overload) {
 148       if (overload->impl)
 149          nir_foreach_block(overload->impl, mark_indirect_uses_block,
 150                            indirect_set);
 151    }
 152
 153    unsigned location = 0;
 154
 155    foreach_list_typed(nir_variable, var, node, var_list) {
 156       if (var->data.mode == nir_var_uniform && var->interface_type != NULL)
 157          continue;
 158
 159       if (_mesa_set_search(indirect_set, var))
 160          continue;
 161
 162       var->data.driver_location = location;
 163       location += type_size(var->type);
 164    }
 165
 166    *direct_size = location;
 167
 168    foreach_list_typed(nir_variable, var, node, var_list) {
 169       if (var->data.mode == nir_var_uniform && var->interface_type != NULL)
 170          continue;
 171
 172       if (!_mesa_set_search(indirect_set, var))
 173          continue;
 174
 175       var->data.driver_location = location;
 176       location += type_size(var->type);
 177    }
 178
 179    *size = location;
 180
 181    _mesa_set_destroy(indirect_set, NULL);
 182 }
 183
 184 static unsigned
 185 get_io_offset(nir_deref_var *deref, nir_instr *instr, nir_src *indirect,
 186               struct lower_io_state *state)
 187 {
 188    bool found_indirect = false;
 189    unsigned base_offset = 0;
 190
 191    nir_deref *tail = &deref->deref;
 192    while (tail->child != NULL) {
 193       const struct glsl_type *parent_type = tail->type;
 194       tail = tail->child;
 195
 196       if (tail->deref_type == nir_deref_type_array) {
 197          nir_deref_array *deref_array = nir_deref_as_array(tail);
 198          unsigned size = type_size(tail->type);
 199
 200          base_offset += size * deref_array->base_offset;
 201
 202          if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
 203             nir_load_const_instr *load_const =
 204                nir_load_const_instr_create(state->mem_ctx, 1);
 205             load_const->value.u[0] = size;
 206             nir_instr_insert_before(instr, &load_const->instr);
 207
 208             nir_alu_instr *mul = nir_alu_instr_create(state->mem_ctx,
 209                                                       nir_op_imul);
 210             mul->src[0].src.is_ssa = true;
 211             mul->src[0].src.ssa = &load_const->def;
 212             nir_src_copy(&mul->src[1].src, &deref_array->indirect,
 213                          state->mem_ctx);
 214             mul->dest.write_mask = 1;
 215             nir_ssa_dest_init(&mul->instr, &mul->dest.dest, 1, NULL);
 216             nir_instr_insert_before(instr, &mul->instr);
 217
 218             if (found_indirect) {
 219                nir_alu_instr *add = nir_alu_instr_create(state->mem_ctx,
 220                                                          nir_op_iadd);
 221                add->src[0].src = *indirect;
 222                add->src[1].src.is_ssa = true;
 223                add->src[1].src.ssa = &mul->dest.dest.ssa;
 224                add->dest.write_mask = 1;
 225                nir_ssa_dest_init(&add->instr, &add->dest.dest, 1, NULL);
 226                nir_instr_insert_before(instr, &add->instr);
 227
 228                indirect->is_ssa = true;
 229                indirect->ssa = &add->dest.dest.ssa;
 230             } else {
 231                indirect->is_ssa = true;
 232                indirect->ssa = &mul->dest.dest.ssa;
 233                found_indirect = true;
 234             }
 235          }
 236       } else if (tail->deref_type == nir_deref_type_struct) {
 237          nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
 238
 239          for (unsigned i = 0; i < deref_struct->index; i++)
 240             base_offset += type_size(glsl_get_struct_field(parent_type, i));
 241       }
 242    }
 243
 244    return base_offset;
 245 }
 246
 247 static bool
 248 nir_lower_io_block(nir_block *block, void *void_state)
 249 {
 250    struct lower_io_state *state = void_state;
 251
 252    nir_foreach_instr_safe(block, instr) {
 253       if (instr->type != nir_instr_type_intrinsic)
 254          continue;
 255
 256       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
 257
 258       switch (intrin->intrinsic) {
 259       case nir_intrinsic_load_var: {
 260          nir_variable_mode mode = intrin->variables[0]->var->data.mode;
 261          if (mode != nir_var_shader_in && mode != nir_var_uniform)
 262             continue;
 263
 264          bool has_indirect = deref_has_indirect(intrin->variables[0]);
 265
 266          /* Figure out the opcode */
 267          nir_intrinsic_op load_op;
 268          switch (mode) {
 269          case nir_var_shader_in:
 270             load_op = has_indirect ? nir_intrinsic_load_input_indirect :
 271                                      nir_intrinsic_load_input;
 272             break;
 273          case nir_var_uniform:
 274             load_op = has_indirect ? nir_intrinsic_load_uniform_indirect :
 275                                      nir_intrinsic_load_uniform;
 276             break;
 277          default:
 278             unreachable("Unknown variable mode");
 279          }
 280
 281          nir_intrinsic_instr *load = nir_intrinsic_instr_create(state->mem_ctx,
 282                                                                 load_op);
 283          load->num_components = intrin->num_components;
 284
 285          nir_src indirect;
 286          unsigned offset = get_io_offset(intrin->variables[0],
 287                                          &intrin->instr, &indirect, state);
 288          offset += intrin->variables[0]->var->data.driver_location;
 289
 290          load->const_index[0] = offset;
 291
 292          if (has_indirect)
 293             load->src[0] = indirect;
 294
 295          if (intrin->dest.is_ssa) {
 296             nir_ssa_dest_init(&load->instr, &load->dest,
 297                               intrin->num_components, NULL);
 298             nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
 299                                      nir_src_for_ssa(&load->dest.ssa),
 300                                      state->mem_ctx);
 301          } else {
 302             nir_dest_copy(&load->dest, &intrin->dest, state->mem_ctx);
 303          }
 304
 305          nir_instr_insert_before(&intrin->instr, &load->instr);
 306          nir_instr_remove(&intrin->instr);
 307          break;
 308       }
 309
 310       case nir_intrinsic_store_var: {
 311          if (intrin->variables[0]->var->data.mode != nir_var_shader_out)
 312             continue;
 313
 314          bool has_indirect = deref_has_indirect(intrin->variables[0]);
 315
 316          nir_intrinsic_op store_op;
 317          if (has_indirect) {
 318             store_op = nir_intrinsic_store_output_indirect;
 319          } else {
 320             store_op = nir_intrinsic_store_output;
 321          }
 322
 323          nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,
 324                                                                  store_op);
 325          store->num_components = intrin->num_components;
 326
 327          nir_src indirect;
 328          unsigned offset = get_io_offset(intrin->variables[0],
 329                                          &intrin->instr, &indirect, state);
 330          offset += intrin->variables[0]->var->data.driver_location;
 331
 332          store->const_index[0] = offset;
 333
 334          nir_src_copy(&store->src[0], &intrin->src[0], state->mem_ctx);
 335
 336          if (has_indirect)
 337             store->src[1] = indirect;
 338
 339          nir_instr_insert_before(&intrin->instr, &store->instr);
 340          nir_instr_remove(&intrin->instr);
 341          break;
 342       }
 343
 344       default:
 345          break;
 346       }
 347    }
 348
 349    return true;
 350 }
 351
 352 static void
 353 nir_lower_io_impl(nir_function_impl *impl)
 354 {
 355    struct lower_io_state state;
 356
 357    state.mem_ctx = ralloc_parent(impl);
 358
 359    nir_foreach_block(impl, nir_lower_io_block, &state);
 360
 361    nir_metadata_preserve(impl, nir_metadata_block_index |
 362                                nir_metadata_dominance);
 363 }
 364
 365 void
 366 nir_lower_io(nir_shader *shader)
 367 {
 368    nir_foreach_overload(shader, overload) {
 369       if (overload->impl)
 370          nir_lower_io_impl(overload->impl);
 371    }
 372 }