src/compiler/glsl/ast_type.cpp

   1 /*
   2  * Copyright © 2010 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
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include "ast.h"
  25
  26 void
  27 ast_type_specifier::print(void) const
  28 {
  29    if (structure) {
  30       structure->print();
  31    } else {
  32       printf("%s ", type_name);
  33    }
  34
  35    if (array_specifier) {
  36       array_specifier->print();
  37    }
  38 }
  39
  40 bool
  41 ast_fully_specified_type::has_qualifiers(_mesa_glsl_parse_state *state) const
  42 {
  43    /* 'subroutine' isnt a real qualifier. */
  44    ast_type_qualifier subroutine_only;
  45    subroutine_only.flags.i = 0;
  46    subroutine_only.flags.q.subroutine = 1;
  47    subroutine_only.flags.q.subroutine_def = 1;
  48    if (state->has_explicit_uniform_location()) {
  49       subroutine_only.flags.q.explicit_index = 1;
  50    }
  51    return (this->qualifier.flags.i & ~subroutine_only.flags.i) != 0;
  52 }
  53
  54 bool ast_type_qualifier::has_interpolation() const
  55 {
  56    return this->flags.q.smooth
  57           || this->flags.q.flat
  58           || this->flags.q.noperspective;
  59 }
  60
  61 bool
  62 ast_type_qualifier::has_layout() const
  63 {
  64    return this->flags.q.origin_upper_left
  65           || this->flags.q.pixel_center_integer
  66           || this->flags.q.depth_any
  67           || this->flags.q.depth_greater
  68           || this->flags.q.depth_less
  69           || this->flags.q.depth_unchanged
  70           || this->flags.q.std140
  71           || this->flags.q.std430
  72           || this->flags.q.shared
  73           || this->flags.q.column_major
  74           || this->flags.q.row_major
  75           || this->flags.q.packed
  76           || this->flags.q.explicit_align
  77           || this->flags.q.explicit_location
  78           || this->flags.q.explicit_image_format
  79           || this->flags.q.explicit_index
  80           || this->flags.q.explicit_binding
  81           || this->flags.q.explicit_offset
  82           || this->flags.q.explicit_stream;
  83 }
  84
  85 bool
  86 ast_type_qualifier::has_storage() const
  87 {
  88    return this->flags.q.constant
  89           || this->flags.q.attribute
  90           || this->flags.q.varying
  91           || this->flags.q.in
  92           || this->flags.q.out
  93           || this->flags.q.uniform
  94           || this->flags.q.buffer
  95           || this->flags.q.shared_storage;
  96 }
  97
  98 bool
  99 ast_type_qualifier::has_auxiliary_storage() const
 100 {
 101    return this->flags.q.centroid
 102           || this->flags.q.sample
 103           || this->flags.q.patch;
 104 }
 105
 106 /**
 107  * This function merges both duplicate identifies within a single layout and
 108  * multiple layout qualifiers on a single variable declaration. The
 109  * is_single_layout_merge param is used differentiate between the two.
 110  */
 111 bool
 112 ast_type_qualifier::merge_qualifier(YYLTYPE *loc,
 113                                     _mesa_glsl_parse_state *state,
 114                                     const ast_type_qualifier &q,
 115                                     bool is_single_layout_merge)
 116 {
 117    ast_type_qualifier ubo_mat_mask;
 118    ubo_mat_mask.flags.i = 0;
 119    ubo_mat_mask.flags.q.row_major = 1;
 120    ubo_mat_mask.flags.q.column_major = 1;
 121
 122    ast_type_qualifier ubo_layout_mask;
 123    ubo_layout_mask.flags.i = 0;
 124    ubo_layout_mask.flags.q.std140 = 1;
 125    ubo_layout_mask.flags.q.packed = 1;
 126    ubo_layout_mask.flags.q.shared = 1;
 127    ubo_layout_mask.flags.q.std430 = 1;
 128
 129    ast_type_qualifier ubo_binding_mask;
 130    ubo_binding_mask.flags.i = 0;
 131    ubo_binding_mask.flags.q.explicit_binding = 1;
 132    ubo_binding_mask.flags.q.explicit_offset = 1;
 133
 134    ast_type_qualifier stream_layout_mask;
 135    stream_layout_mask.flags.i = 0;
 136    stream_layout_mask.flags.q.stream = 1;
 137
 138    /* FIXME: We should probably do interface and function param validation
 139     * separately.
 140     */
 141    ast_type_qualifier input_layout_mask;
 142    input_layout_mask.flags.i = 0;
 143    input_layout_mask.flags.q.centroid = 1;
 144    /* Function params can have constant */
 145    input_layout_mask.flags.q.constant = 1;
 146    input_layout_mask.flags.q.explicit_location = 1;
 147    input_layout_mask.flags.q.flat = 1;
 148    input_layout_mask.flags.q.in = 1;
 149    input_layout_mask.flags.q.invariant = 1;
 150    input_layout_mask.flags.q.noperspective = 1;
 151    input_layout_mask.flags.q.origin_upper_left = 1;
 152    /* Function params 'inout' will set this */
 153    input_layout_mask.flags.q.out = 1;
 154    input_layout_mask.flags.q.patch = 1;
 155    input_layout_mask.flags.q.pixel_center_integer = 1;
 156    input_layout_mask.flags.q.precise = 1;
 157    input_layout_mask.flags.q.sample = 1;
 158    input_layout_mask.flags.q.smooth = 1;
 159
 160    /* Uniform block layout qualifiers get to overwrite each
 161     * other (rightmost having priority), while all other
 162     * qualifiers currently don't allow duplicates.
 163     */
 164    ast_type_qualifier allowed_duplicates_mask;
 165    allowed_duplicates_mask.flags.i =
 166       ubo_mat_mask.flags.i |
 167       ubo_layout_mask.flags.i |
 168       ubo_binding_mask.flags.i;
 169
 170    /* Geometry shaders can have several layout qualifiers
 171     * assigning different stream values.
 172     */
 173    if (state->stage == MESA_SHADER_GEOMETRY)
 174       allowed_duplicates_mask.flags.i |=
 175          stream_layout_mask.flags.i;
 176
 177    if (is_single_layout_merge && !state->has_enhanced_layouts() &&
 178        (this->flags.i & q.flags.i & ~allowed_duplicates_mask.flags.i) != 0) {
 179       _mesa_glsl_error(loc, state,
 180                        "duplicate layout qualifiers used");
 181       return false;
 182    }
 183
 184    if (q.flags.q.prim_type) {
 185       if (this->flags.q.prim_type && this->prim_type != q.prim_type) {
 186          _mesa_glsl_error(loc, state,
 187                           "conflicting primitive type qualifiers used");
 188          return false;
 189       }
 190       this->prim_type = q.prim_type;
 191    }
 192
 193    if (q.flags.q.max_vertices) {
 194       if (this->max_vertices) {
 195          this->max_vertices->merge_qualifier(q.max_vertices);
 196       } else {
 197          this->max_vertices = q.max_vertices;
 198       }
 199    }
 200
 201    if (q.flags.q.subroutine_def) {
 202       if (this->flags.q.subroutine_def) {
 203          _mesa_glsl_error(loc, state,
 204                           "conflicting subroutine qualifiers used");
 205       } else {
 206          this->subroutine_list = q.subroutine_list;
 207       }
 208    }
 209
 210    if (q.flags.q.invocations) {
 211       if (this->invocations) {
 212          this->invocations->merge_qualifier(q.invocations);
 213       } else {
 214          this->invocations = q.invocations;
 215       }
 216    }
 217
 218    if (state->stage == MESA_SHADER_GEOMETRY &&
 219        state->has_explicit_attrib_stream()) {
 220       if (!this->flags.q.explicit_stream) {
 221          if (q.flags.q.stream) {
 222             this->flags.q.stream = 1;
 223             this->stream = q.stream;
 224          } else if (!this->flags.q.stream && this->flags.q.out) {
 225             /* Assign default global stream value */
 226             this->flags.q.stream = 1;
 227             this->stream = state->out_qualifier->stream;
 228          }
 229       }
 230    }
 231
 232    if (state->has_enhanced_layouts()) {
 233       if (!this->flags.q.explicit_xfb_buffer) {
 234          if (q.flags.q.xfb_buffer) {
 235             this->flags.q.xfb_buffer = 1;
 236             this->xfb_buffer = q.xfb_buffer;
 237          } else if (!this->flags.q.xfb_buffer && this->flags.q.out) {
 238             /* Assign global xfb_buffer value */
 239             this->flags.q.xfb_buffer = 1;
 240             this->xfb_buffer = state->out_qualifier->xfb_buffer;
 241          }
 242       }
 243
 244       if (q.flags.q.explicit_xfb_stride)
 245          this->xfb_stride = q.xfb_stride;
 246
 247       /* Merge all we xfb_stride qualifiers into the global out */
 248       if (q.flags.q.explicit_xfb_stride || this->flags.q.xfb_stride) {
 249
 250          /* Set xfb_stride flag to 0 to avoid adding duplicates every time
 251           * there is a merge.
 252           */
 253          this->flags.q.xfb_stride = 0;
 254
 255          unsigned buff_idx;
 256          if (process_qualifier_constant(state, loc, "xfb_buffer",
 257                                         this->xfb_buffer, &buff_idx)) {
 258             if (state->out_qualifier->out_xfb_stride[buff_idx]) {
 259                state->out_qualifier->out_xfb_stride[buff_idx]->merge_qualifier(
 260                   new(state) ast_layout_expression(*loc, this->xfb_stride));
 261             } else {
 262                state->out_qualifier->out_xfb_stride[buff_idx] =
 263                   new(state) ast_layout_expression(*loc, this->xfb_stride);
 264             }
 265          }
 266       }
 267    }
 268
 269    if (q.flags.q.vertices) {
 270       if (this->vertices) {
 271          this->vertices->merge_qualifier(q.vertices);
 272       } else {
 273          this->vertices = q.vertices;
 274       }
 275    }
 276
 277    if (q.flags.q.vertex_spacing) {
 278       if (this->flags.q.vertex_spacing && this->vertex_spacing != q.vertex_spacing) {
 279          _mesa_glsl_error(loc, state,
 280                           "conflicting vertex spacing used");
 281          return false;
 282       }
 283       this->vertex_spacing = q.vertex_spacing;
 284    }
 285
 286    if (q.flags.q.ordering) {
 287       if (this->flags.q.ordering && this->ordering != q.ordering) {
 288          _mesa_glsl_error(loc, state,
 289                           "conflicting ordering used");
 290          return false;
 291       }
 292       this->ordering = q.ordering;
 293    }
 294
 295    if (q.flags.q.point_mode) {
 296       if (this->flags.q.point_mode && this->point_mode != q.point_mode) {
 297          _mesa_glsl_error(loc, state,
 298                           "conflicting point mode used");
 299          return false;
 300       }
 301       this->point_mode = q.point_mode;
 302    }
 303
 304    if ((q.flags.i & ubo_mat_mask.flags.i) != 0)
 305       this->flags.i &= ~ubo_mat_mask.flags.i;
 306    if ((q.flags.i & ubo_layout_mask.flags.i) != 0)
 307       this->flags.i &= ~ubo_layout_mask.flags.i;
 308
 309    for (int i = 0; i < 3; i++) {
 310       if (q.flags.q.local_size & (1 << i)) {
 311          if (this->local_size[i]) {
 312             this->local_size[i]->merge_qualifier(q.local_size[i]);
 313          } else {
 314             this->local_size[i] = q.local_size[i];
 315          }
 316       }
 317    }
 318
 319    this->flags.i |= q.flags.i;
 320
 321    if (this->flags.q.in &&
 322        (this->flags.i & ~input_layout_mask.flags.i) != 0) {
 323       _mesa_glsl_error(loc, state,
 324                        "invalid input layout qualifier used");
 325       return false;
 326    }
 327
 328    if (q.flags.q.explicit_align)
 329       this->align = q.align;
 330
 331    if (q.flags.q.explicit_location)
 332       this->location = q.location;
 333
 334    if (q.flags.q.explicit_index)
 335       this->index = q.index;
 336
 337    if (q.flags.q.explicit_binding)
 338       this->binding = q.binding;
 339
 340    if (q.flags.q.explicit_offset || q.flags.q.explicit_xfb_offset)
 341       this->offset = q.offset;
 342
 343    if (q.precision != ast_precision_none)
 344       this->precision = q.precision;
 345
 346    if (q.flags.q.explicit_image_format) {
 347       this->image_format = q.image_format;
 348       this->image_base_type = q.image_base_type;
 349    }
 350
 351    return true;
 352 }
 353
 354 bool
 355 ast_type_qualifier::merge_out_qualifier(YYLTYPE *loc,
 356                                         _mesa_glsl_parse_state *state,
 357                                         const ast_type_qualifier &q,
 358                                         ast_node* &node, bool create_node)
 359 {
 360    void *mem_ctx = state;
 361    const bool r = this->merge_qualifier(loc, state, q, false);
 362    ast_type_qualifier valid_out_mask;
 363    valid_out_mask.flags.i = 0;
 364
 365    if (state->stage == MESA_SHADER_GEOMETRY) {
 366       if (q.flags.q.prim_type) {
 367          /* Make sure this is a valid output primitive type. */
 368          switch (q.prim_type) {
 369          case GL_POINTS:
 370          case GL_LINE_STRIP:
 371          case GL_TRIANGLE_STRIP:
 372             break;
 373          default:
 374             _mesa_glsl_error(loc, state, "invalid geometry shader output "
 375                              "primitive type");
 376             break;
 377          }
 378       }
 379
 380       /* Allow future assigments of global out's stream id value */
 381       this->flags.q.explicit_stream = 0;
 382
 383       valid_out_mask.flags.q.stream = 1;
 384       valid_out_mask.flags.q.explicit_stream = 1;
 385       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 386       valid_out_mask.flags.q.xfb_buffer = 1;
 387       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 388       valid_out_mask.flags.q.xfb_stride = 1;
 389       valid_out_mask.flags.q.max_vertices = 1;
 390       valid_out_mask.flags.q.prim_type = 1;
 391    } else if (state->stage == MESA_SHADER_TESS_CTRL) {
 392       if (create_node) {
 393          node = new(mem_ctx) ast_tcs_output_layout(*loc);
 394       }
 395       valid_out_mask.flags.q.vertices = 1;
 396       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 397       valid_out_mask.flags.q.xfb_buffer = 1;
 398       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 399       valid_out_mask.flags.q.xfb_stride = 1;
 400    } else if (state->stage == MESA_SHADER_TESS_EVAL ||
 401               state->stage == MESA_SHADER_VERTEX) {
 402       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 403       valid_out_mask.flags.q.xfb_buffer = 1;
 404       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 405       valid_out_mask.flags.q.xfb_stride = 1;
 406    } else {
 407       _mesa_glsl_error(loc, state, "out layout qualifiers only valid in "
 408                        "geometry, tessellation and vertex shaders");
 409       return false;
 410    }
 411
 412    /* Allow future assigments of global out's */
 413    this->flags.q.explicit_xfb_buffer = 0;
 414    this->flags.q.explicit_xfb_stride = 0;
 415
 416    /* Generate an error when invalid input layout qualifiers are used. */
 417    if ((q.flags.i & ~valid_out_mask.flags.i) != 0) {
 418       _mesa_glsl_error(loc, state,
 419                        "invalid output layout qualifiers used");
 420       return false;
 421    }
 422
 423    return r;
 424 }
 425
 426 bool
 427 ast_type_qualifier::merge_in_qualifier(YYLTYPE *loc,
 428                                        _mesa_glsl_parse_state *state,
 429                                        const ast_type_qualifier &q,
 430                                        ast_node* &node, bool create_node)
 431 {
 432    void *mem_ctx = state;
 433    bool create_gs_ast = false;
 434    bool create_cs_ast = false;
 435    ast_type_qualifier valid_in_mask;
 436    valid_in_mask.flags.i = 0;
 437
 438    switch (state->stage) {
 439    case MESA_SHADER_TESS_EVAL:
 440       if (q.flags.q.prim_type) {
 441          /* Make sure this is a valid input primitive type. */
 442          switch (q.prim_type) {
 443          case GL_TRIANGLES:
 444          case GL_QUADS:
 445          case GL_ISOLINES:
 446             break;
 447          default:
 448             _mesa_glsl_error(loc, state,
 449                              "invalid tessellation evaluation "
 450                              "shader input primitive type");
 451             break;
 452          }
 453       }
 454
 455       valid_in_mask.flags.q.prim_type = 1;
 456       valid_in_mask.flags.q.vertex_spacing = 1;
 457       valid_in_mask.flags.q.ordering = 1;
 458       valid_in_mask.flags.q.point_mode = 1;
 459       break;
 460    case MESA_SHADER_GEOMETRY:
 461       if (q.flags.q.prim_type) {
 462          /* Make sure this is a valid input primitive type. */
 463          switch (q.prim_type) {
 464          case GL_POINTS:
 465          case GL_LINES:
 466          case GL_LINES_ADJACENCY:
 467          case GL_TRIANGLES:
 468          case GL_TRIANGLES_ADJACENCY:
 469             break;
 470          default:
 471             _mesa_glsl_error(loc, state,
 472                              "invalid geometry shader input primitive type");
 473             break;
 474          }
 475       }
 476
 477       create_gs_ast |=
 478          q.flags.q.prim_type &&
 479          !state->in_qualifier->flags.q.prim_type;
 480
 481       valid_in_mask.flags.q.prim_type = 1;
 482       valid_in_mask.flags.q.invocations = 1;
 483       break;
 484    case MESA_SHADER_FRAGMENT:
 485       valid_in_mask.flags.q.early_fragment_tests = 1;
 486       break;
 487    case MESA_SHADER_COMPUTE:
 488       create_cs_ast |=
 489          q.flags.q.local_size != 0 &&
 490          state->in_qualifier->flags.q.local_size == 0;
 491
 492       valid_in_mask.flags.q.local_size = 7;
 493       break;
 494    default:
 495       _mesa_glsl_error(loc, state,
 496                        "input layout qualifiers only valid in "
 497                        "geometry, fragment and compute shaders");
 498       break;
 499    }
 500
 501    /* Generate an error when invalid input layout qualifiers are used. */
 502    if ((q.flags.i & ~valid_in_mask.flags.i) != 0) {
 503       _mesa_glsl_error(loc, state,
 504                        "invalid input layout qualifiers used");
 505       return false;
 506    }
 507
 508    /* Input layout qualifiers can be specified multiple
 509     * times in separate declarations, as long as they match.
 510     */
 511    if (this->flags.q.prim_type) {
 512       if (q.flags.q.prim_type &&
 513           this->prim_type != q.prim_type) {
 514          _mesa_glsl_error(loc, state,
 515                           "conflicting input primitive %s specified",
 516                           state->stage == MESA_SHADER_GEOMETRY ?
 517                           "type" : "mode");
 518       }
 519    } else if (q.flags.q.prim_type) {
 520       state->in_qualifier->flags.q.prim_type = 1;
 521       state->in_qualifier->prim_type = q.prim_type;
 522    }
 523
 524    if (q.flags.q.invocations) {
 525       this->flags.q.invocations = 1;
 526       if (this->invocations) {
 527          this->invocations->merge_qualifier(q.invocations);
 528       } else {
 529          this->invocations = q.invocations;
 530       }
 531    }
 532
 533    if (q.flags.q.early_fragment_tests) {
 534       state->fs_early_fragment_tests = true;
 535    }
 536
 537    if (this->flags.q.vertex_spacing) {
 538       if (q.flags.q.vertex_spacing &&
 539           this->vertex_spacing != q.vertex_spacing) {
 540          _mesa_glsl_error(loc, state,
 541                           "conflicting vertex spacing specified");
 542       }
 543    } else if (q.flags.q.vertex_spacing) {
 544       this->flags.q.vertex_spacing = 1;
 545       this->vertex_spacing = q.vertex_spacing;
 546    }
 547
 548    if (this->flags.q.ordering) {
 549       if (q.flags.q.ordering &&
 550           this->ordering != q.ordering) {
 551          _mesa_glsl_error(loc, state,
 552                           "conflicting ordering specified");
 553       }
 554    } else if (q.flags.q.ordering) {
 555       this->flags.q.ordering = 1;
 556       this->ordering = q.ordering;
 557    }
 558
 559    if (this->flags.q.point_mode) {
 560       if (q.flags.q.point_mode &&
 561           this->point_mode != q.point_mode) {
 562          _mesa_glsl_error(loc, state,
 563                           "conflicting point mode specified");
 564       }
 565    } else if (q.flags.q.point_mode) {
 566       this->flags.q.point_mode = 1;
 567       this->point_mode = q.point_mode;
 568    }
 569
 570    if (create_node) {
 571       if (create_gs_ast) {
 572          node = new(mem_ctx) ast_gs_input_layout(*loc, q.prim_type);
 573       } else if (create_cs_ast) {
 574          node = new(mem_ctx) ast_cs_input_layout(*loc, q.local_size);
 575       }
 576    }
 577
 578    return true;
 579 }
 580
 581 bool
 582 ast_layout_expression::process_qualifier_constant(struct _mesa_glsl_parse_state *state,
 583                                                   const char *qual_indentifier,
 584                                                   unsigned *value,
 585                                                   bool can_be_zero)
 586 {
 587    int min_value = 0;
 588    bool first_pass = true;
 589    *value = 0;
 590
 591    if (!can_be_zero)
 592       min_value = 1;
 593
 594    for (exec_node *node = layout_const_expressions.head;
 595            !node->is_tail_sentinel(); node = node->next) {
 596
 597       exec_list dummy_instructions;
 598       ast_node *const_expression = exec_node_data(ast_node, node, link);
 599
 600       ir_rvalue *const ir = const_expression->hir(&dummy_instructions, state);
 601
 602       ir_constant *const const_int = ir->constant_expression_value();
 603       if (const_int == NULL || !const_int->type->is_integer()) {
 604          YYLTYPE loc = const_expression->get_location();
 605          _mesa_glsl_error(&loc, state, "%s must be an integral constant "
 606                           "expression", qual_indentifier);
 607          return false;
 608       }
 609
 610       if (const_int->value.i[0] < min_value) {
 611          YYLTYPE loc = const_expression->get_location();
 612          _mesa_glsl_error(&loc, state, "%s layout qualifier is invalid "
 613                           "(%d < %d)", qual_indentifier,
 614                           const_int->value.i[0], min_value);
 615          return false;
 616       }
 617
 618       if (!first_pass && *value != const_int->value.u[0]) {
 619          YYLTYPE loc = const_expression->get_location();
 620          _mesa_glsl_error(&loc, state, "%s layout qualifier does not "
 621                           "match previous declaration (%d vs %d)",
 622                           qual_indentifier, *value, const_int->value.i[0]);
 623          return false;
 624       } else {
 625          first_pass = false;
 626          *value = const_int->value.u[0];
 627       }
 628
 629       /* If the location is const (and we've verified that
 630        * it is) then no instructions should have been emitted
 631        * when we converted it to HIR. If they were emitted,
 632        * then either the location isn't const after all, or
 633        * we are emitting unnecessary instructions.
 634        */
 635       assert(dummy_instructions.is_empty());
 636    }
 637
 638    return true;
 639 }
 640
 641 bool
 642 process_qualifier_constant(struct _mesa_glsl_parse_state *state,
 643                            YYLTYPE *loc,
 644                            const char *qual_indentifier,
 645                            ast_expression *const_expression,
 646                            unsigned *value)
 647 {
 648    exec_list dummy_instructions;
 649
 650    if (const_expression == NULL) {
 651       *value = 0;
 652       return true;
 653    }
 654
 655    ir_rvalue *const ir = const_expression->hir(&dummy_instructions, state);
 656
 657    ir_constant *const const_int = ir->constant_expression_value();
 658    if (const_int == NULL || !const_int->type->is_integer()) {
 659       _mesa_glsl_error(loc, state, "%s must be an integral constant "
 660                        "expression", qual_indentifier);
 661       return false;
 662    }
 663
 664    if (const_int->value.i[0] < 0) {
 665       _mesa_glsl_error(loc, state, "%s layout qualifier is invalid (%d < 0)",
 666                        qual_indentifier, const_int->value.u[0]);
 667       return false;
 668    }
 669
 670    /* If the location is const (and we've verified that
 671     * it is) then no instructions should have been emitted
 672     * when we converted it to HIR. If they were emitted,
 673     * then either the location isn't const after all, or
 674     * we are emitting unnecessary instructions.
 675     */
 676    assert(dummy_instructions.is_empty());
 677
 678    *value = const_int->value.u[0];
 679    return true;
 680 }