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           || this->flags.q.explicit_xfb_buffer
  84           || this->flags.q.explicit_xfb_offset
  85           || this->flags.q.explicit_xfb_stride;
  86 }
  87
  88 bool
  89 ast_type_qualifier::has_storage() const
  90 {
  91    return this->flags.q.constant
  92           || this->flags.q.attribute
  93           || this->flags.q.varying
  94           || this->flags.q.in
  95           || this->flags.q.out
  96           || this->flags.q.uniform
  97           || this->flags.q.buffer
  98           || this->flags.q.shared_storage;
  99 }
 100
 101 bool
 102 ast_type_qualifier::has_auxiliary_storage() const
 103 {
 104    return this->flags.q.centroid
 105           || this->flags.q.sample
 106           || this->flags.q.patch;
 107 }
 108
 109 /**
 110  * This function merges both duplicate identifies within a single layout and
 111  * multiple layout qualifiers on a single variable declaration. The
 112  * is_single_layout_merge param is used differentiate between the two.
 113  */
 114 bool
 115 ast_type_qualifier::merge_qualifier(YYLTYPE *loc,
 116                                     _mesa_glsl_parse_state *state,
 117                                     const ast_type_qualifier &q,
 118                                     bool is_single_layout_merge)
 119 {
 120    ast_type_qualifier ubo_mat_mask;
 121    ubo_mat_mask.flags.i = 0;
 122    ubo_mat_mask.flags.q.row_major = 1;
 123    ubo_mat_mask.flags.q.column_major = 1;
 124
 125    ast_type_qualifier ubo_layout_mask;
 126    ubo_layout_mask.flags.i = 0;
 127    ubo_layout_mask.flags.q.std140 = 1;
 128    ubo_layout_mask.flags.q.packed = 1;
 129    ubo_layout_mask.flags.q.shared = 1;
 130    ubo_layout_mask.flags.q.std430 = 1;
 131
 132    ast_type_qualifier ubo_binding_mask;
 133    ubo_binding_mask.flags.i = 0;
 134    ubo_binding_mask.flags.q.explicit_binding = 1;
 135    ubo_binding_mask.flags.q.explicit_offset = 1;
 136
 137    ast_type_qualifier stream_layout_mask;
 138    stream_layout_mask.flags.i = 0;
 139    stream_layout_mask.flags.q.stream = 1;
 140
 141    /* FIXME: We should probably do interface and function param validation
 142     * separately.
 143     */
 144    ast_type_qualifier input_layout_mask;
 145    input_layout_mask.flags.i = 0;
 146    input_layout_mask.flags.q.centroid = 1;
 147    /* Function params can have constant */
 148    input_layout_mask.flags.q.constant = 1;
 149    input_layout_mask.flags.q.explicit_location = 1;
 150    input_layout_mask.flags.q.flat = 1;
 151    input_layout_mask.flags.q.in = 1;
 152    input_layout_mask.flags.q.invariant = 1;
 153    input_layout_mask.flags.q.noperspective = 1;
 154    input_layout_mask.flags.q.origin_upper_left = 1;
 155    /* Function params 'inout' will set this */
 156    input_layout_mask.flags.q.out = 1;
 157    input_layout_mask.flags.q.patch = 1;
 158    input_layout_mask.flags.q.pixel_center_integer = 1;
 159    input_layout_mask.flags.q.precise = 1;
 160    input_layout_mask.flags.q.sample = 1;
 161    input_layout_mask.flags.q.smooth = 1;
 162
 163    /* Uniform block layout qualifiers get to overwrite each
 164     * other (rightmost having priority), while all other
 165     * qualifiers currently don't allow duplicates.
 166     */
 167    ast_type_qualifier allowed_duplicates_mask;
 168    allowed_duplicates_mask.flags.i =
 169       ubo_mat_mask.flags.i |
 170       ubo_layout_mask.flags.i |
 171       ubo_binding_mask.flags.i;
 172
 173    /* Geometry shaders can have several layout qualifiers
 174     * assigning different stream values.
 175     */
 176    if (state->stage == MESA_SHADER_GEOMETRY)
 177       allowed_duplicates_mask.flags.i |=
 178          stream_layout_mask.flags.i;
 179
 180    if (is_single_layout_merge && !state->has_enhanced_layouts() &&
 181        (this->flags.i & q.flags.i & ~allowed_duplicates_mask.flags.i) != 0) {
 182       _mesa_glsl_error(loc, state,
 183                        "duplicate layout qualifiers used");
 184       return false;
 185    }
 186
 187    if (q.flags.q.prim_type) {
 188       if (this->flags.q.prim_type && this->prim_type != q.prim_type) {
 189          _mesa_glsl_error(loc, state,
 190                           "conflicting primitive type qualifiers used");
 191          return false;
 192       }
 193       this->prim_type = q.prim_type;
 194    }
 195
 196    if (q.flags.q.max_vertices) {
 197       if (this->max_vertices) {
 198          this->max_vertices->merge_qualifier(q.max_vertices);
 199       } else {
 200          this->max_vertices = q.max_vertices;
 201       }
 202    }
 203
 204    if (q.flags.q.subroutine_def) {
 205       if (this->flags.q.subroutine_def) {
 206          _mesa_glsl_error(loc, state,
 207                           "conflicting subroutine qualifiers used");
 208       } else {
 209          this->subroutine_list = q.subroutine_list;
 210       }
 211    }
 212
 213    if (q.flags.q.invocations) {
 214       if (this->invocations) {
 215          this->invocations->merge_qualifier(q.invocations);
 216       } else {
 217          this->invocations = q.invocations;
 218       }
 219    }
 220
 221    if (state->stage == MESA_SHADER_GEOMETRY &&
 222        state->has_explicit_attrib_stream()) {
 223       if (!this->flags.q.explicit_stream) {
 224          if (q.flags.q.stream) {
 225             this->flags.q.stream = 1;
 226             this->stream = q.stream;
 227          } else if (!this->flags.q.stream && this->flags.q.out) {
 228             /* Assign default global stream value */
 229             this->flags.q.stream = 1;
 230             this->stream = state->out_qualifier->stream;
 231          }
 232       }
 233    }
 234
 235    if (state->has_enhanced_layouts()) {
 236       if (!this->flags.q.explicit_xfb_buffer) {
 237          if (q.flags.q.xfb_buffer) {
 238             this->flags.q.xfb_buffer = 1;
 239             this->xfb_buffer = q.xfb_buffer;
 240          } else if (!this->flags.q.xfb_buffer && this->flags.q.out) {
 241             /* Assign global xfb_buffer value */
 242             this->flags.q.xfb_buffer = 1;
 243             this->xfb_buffer = state->out_qualifier->xfb_buffer;
 244          }
 245       }
 246
 247       if (q.flags.q.explicit_xfb_stride)
 248          this->xfb_stride = q.xfb_stride;
 249
 250       /* Merge all we xfb_stride qualifiers into the global out */
 251       if (q.flags.q.explicit_xfb_stride || this->flags.q.xfb_stride) {
 252
 253          /* Set xfb_stride flag to 0 to avoid adding duplicates every time
 254           * there is a merge.
 255           */
 256          this->flags.q.xfb_stride = 0;
 257
 258          unsigned buff_idx;
 259          if (process_qualifier_constant(state, loc, "xfb_buffer",
 260                                         this->xfb_buffer, &buff_idx)) {
 261             if (state->out_qualifier->out_xfb_stride[buff_idx]) {
 262                state->out_qualifier->out_xfb_stride[buff_idx]->merge_qualifier(
 263                   new(state) ast_layout_expression(*loc, this->xfb_stride));
 264             } else {
 265                state->out_qualifier->out_xfb_stride[buff_idx] =
 266                   new(state) ast_layout_expression(*loc, this->xfb_stride);
 267             }
 268          }
 269       }
 270    }
 271
 272    if (q.flags.q.vertices) {
 273       if (this->vertices) {
 274          this->vertices->merge_qualifier(q.vertices);
 275       } else {
 276          this->vertices = q.vertices;
 277       }
 278    }
 279
 280    if (q.flags.q.vertex_spacing) {
 281       if (this->flags.q.vertex_spacing && this->vertex_spacing != q.vertex_spacing) {
 282          _mesa_glsl_error(loc, state,
 283                           "conflicting vertex spacing used");
 284          return false;
 285       }
 286       this->vertex_spacing = q.vertex_spacing;
 287    }
 288
 289    if (q.flags.q.ordering) {
 290       if (this->flags.q.ordering && this->ordering != q.ordering) {
 291          _mesa_glsl_error(loc, state,
 292                           "conflicting ordering used");
 293          return false;
 294       }
 295       this->ordering = q.ordering;
 296    }
 297
 298    if (q.flags.q.point_mode) {
 299       if (this->flags.q.point_mode && this->point_mode != q.point_mode) {
 300          _mesa_glsl_error(loc, state,
 301                           "conflicting point mode used");
 302          return false;
 303       }
 304       this->point_mode = q.point_mode;
 305    }
 306
 307    if ((q.flags.i & ubo_mat_mask.flags.i) != 0)
 308       this->flags.i &= ~ubo_mat_mask.flags.i;
 309    if ((q.flags.i & ubo_layout_mask.flags.i) != 0)
 310       this->flags.i &= ~ubo_layout_mask.flags.i;
 311
 312    for (int i = 0; i < 3; i++) {
 313       if (q.flags.q.local_size & (1 << i)) {
 314          if (this->local_size[i]) {
 315             this->local_size[i]->merge_qualifier(q.local_size[i]);
 316          } else {
 317             this->local_size[i] = q.local_size[i];
 318          }
 319       }
 320    }
 321
 322    this->flags.i |= q.flags.i;
 323
 324    if (this->flags.q.in &&
 325        (this->flags.i & ~input_layout_mask.flags.i) != 0) {
 326       _mesa_glsl_error(loc, state,
 327                        "invalid input layout qualifier used");
 328       return false;
 329    }
 330
 331    if (q.flags.q.explicit_align)
 332       this->align = q.align;
 333
 334    if (q.flags.q.explicit_location)
 335       this->location = q.location;
 336
 337    if (q.flags.q.explicit_index)
 338       this->index = q.index;
 339
 340    if (q.flags.q.explicit_binding)
 341       this->binding = q.binding;
 342
 343    if (q.flags.q.explicit_offset || q.flags.q.explicit_xfb_offset)
 344       this->offset = q.offset;
 345
 346    if (q.precision != ast_precision_none)
 347       this->precision = q.precision;
 348
 349    if (q.flags.q.explicit_image_format) {
 350       this->image_format = q.image_format;
 351       this->image_base_type = q.image_base_type;
 352    }
 353
 354    return true;
 355 }
 356
 357 bool
 358 ast_type_qualifier::merge_out_qualifier(YYLTYPE *loc,
 359                                         _mesa_glsl_parse_state *state,
 360                                         const ast_type_qualifier &q,
 361                                         ast_node* &node, bool create_node)
 362 {
 363    void *mem_ctx = state;
 364    const bool r = this->merge_qualifier(loc, state, q, false);
 365    ast_type_qualifier valid_out_mask;
 366    valid_out_mask.flags.i = 0;
 367
 368    if (state->stage == MESA_SHADER_GEOMETRY) {
 369       if (q.flags.q.prim_type) {
 370          /* Make sure this is a valid output primitive type. */
 371          switch (q.prim_type) {
 372          case GL_POINTS:
 373          case GL_LINE_STRIP:
 374          case GL_TRIANGLE_STRIP:
 375             break;
 376          default:
 377             _mesa_glsl_error(loc, state, "invalid geometry shader output "
 378                              "primitive type");
 379             break;
 380          }
 381       }
 382
 383       /* Allow future assigments of global out's stream id value */
 384       this->flags.q.explicit_stream = 0;
 385
 386       valid_out_mask.flags.q.stream = 1;
 387       valid_out_mask.flags.q.explicit_stream = 1;
 388       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 389       valid_out_mask.flags.q.xfb_buffer = 1;
 390       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 391       valid_out_mask.flags.q.xfb_stride = 1;
 392       valid_out_mask.flags.q.max_vertices = 1;
 393       valid_out_mask.flags.q.prim_type = 1;
 394    } else if (state->stage == MESA_SHADER_TESS_CTRL) {
 395       if (create_node) {
 396          node = new(mem_ctx) ast_tcs_output_layout(*loc);
 397       }
 398       valid_out_mask.flags.q.vertices = 1;
 399       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 400       valid_out_mask.flags.q.xfb_buffer = 1;
 401       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 402       valid_out_mask.flags.q.xfb_stride = 1;
 403    } else if (state->stage == MESA_SHADER_TESS_EVAL ||
 404               state->stage == MESA_SHADER_VERTEX) {
 405       valid_out_mask.flags.q.explicit_xfb_buffer = 1;
 406       valid_out_mask.flags.q.xfb_buffer = 1;
 407       valid_out_mask.flags.q.explicit_xfb_stride = 1;
 408       valid_out_mask.flags.q.xfb_stride = 1;
 409    } else {
 410       _mesa_glsl_error(loc, state, "out layout qualifiers only valid in "
 411                        "geometry, tessellation and vertex shaders");
 412       return false;
 413    }
 414
 415    /* Allow future assigments of global out's */
 416    this->flags.q.explicit_xfb_buffer = 0;
 417    this->flags.q.explicit_xfb_stride = 0;
 418
 419    /* Generate an error when invalid input layout qualifiers are used. */
 420    if ((q.flags.i & ~valid_out_mask.flags.i) != 0) {
 421       _mesa_glsl_error(loc, state,
 422                        "invalid output layout qualifiers used");
 423       return false;
 424    }
 425
 426    return r;
 427 }
 428
 429 bool
 430 ast_type_qualifier::merge_in_qualifier(YYLTYPE *loc,
 431                                        _mesa_glsl_parse_state *state,
 432                                        const ast_type_qualifier &q,
 433                                        ast_node* &node, bool create_node)
 434 {
 435    void *mem_ctx = state;
 436    bool create_gs_ast = false;
 437    bool create_cs_ast = false;
 438    ast_type_qualifier valid_in_mask;
 439    valid_in_mask.flags.i = 0;
 440
 441    switch (state->stage) {
 442    case MESA_SHADER_TESS_EVAL:
 443       if (q.flags.q.prim_type) {
 444          /* Make sure this is a valid input primitive type. */
 445          switch (q.prim_type) {
 446          case GL_TRIANGLES:
 447          case GL_QUADS:
 448          case GL_ISOLINES:
 449             break;
 450          default:
 451             _mesa_glsl_error(loc, state,
 452                              "invalid tessellation evaluation "
 453                              "shader input primitive type");
 454             break;
 455          }
 456       }
 457
 458       valid_in_mask.flags.q.prim_type = 1;
 459       valid_in_mask.flags.q.vertex_spacing = 1;
 460       valid_in_mask.flags.q.ordering = 1;
 461       valid_in_mask.flags.q.point_mode = 1;
 462       break;
 463    case MESA_SHADER_GEOMETRY:
 464       if (q.flags.q.prim_type) {
 465          /* Make sure this is a valid input primitive type. */
 466          switch (q.prim_type) {
 467          case GL_POINTS:
 468          case GL_LINES:
 469          case GL_LINES_ADJACENCY:
 470          case GL_TRIANGLES:
 471          case GL_TRIANGLES_ADJACENCY:
 472             break;
 473          default:
 474             _mesa_glsl_error(loc, state,
 475                              "invalid geometry shader input primitive type");
 476             break;
 477          }
 478       }
 479
 480       create_gs_ast |=
 481          q.flags.q.prim_type &&
 482          !state->in_qualifier->flags.q.prim_type;
 483
 484       valid_in_mask.flags.q.prim_type = 1;
 485       valid_in_mask.flags.q.invocations = 1;
 486       break;
 487    case MESA_SHADER_FRAGMENT:
 488       valid_in_mask.flags.q.early_fragment_tests = 1;
 489       break;
 490    case MESA_SHADER_COMPUTE:
 491       create_cs_ast |=
 492          q.flags.q.local_size != 0 &&
 493          state->in_qualifier->flags.q.local_size == 0;
 494
 495       valid_in_mask.flags.q.local_size = 7;
 496       break;
 497    default:
 498       _mesa_glsl_error(loc, state,
 499                        "input layout qualifiers only valid in "
 500                        "geometry, fragment and compute shaders");
 501       break;
 502    }
 503
 504    /* Generate an error when invalid input layout qualifiers are used. */
 505    if ((q.flags.i & ~valid_in_mask.flags.i) != 0) {
 506       _mesa_glsl_error(loc, state,
 507                        "invalid input layout qualifiers used");
 508       return false;
 509    }
 510
 511    /* Input layout qualifiers can be specified multiple
 512     * times in separate declarations, as long as they match.
 513     */
 514    if (this->flags.q.prim_type) {
 515       if (q.flags.q.prim_type &&
 516           this->prim_type != q.prim_type) {
 517          _mesa_glsl_error(loc, state,
 518                           "conflicting input primitive %s specified",
 519                           state->stage == MESA_SHADER_GEOMETRY ?
 520                           "type" : "mode");
 521       }
 522    } else if (q.flags.q.prim_type) {
 523       state->in_qualifier->flags.q.prim_type = 1;
 524       state->in_qualifier->prim_type = q.prim_type;
 525    }
 526
 527    if (q.flags.q.invocations) {
 528       this->flags.q.invocations = 1;
 529       if (this->invocations) {
 530          this->invocations->merge_qualifier(q.invocations);
 531       } else {
 532          this->invocations = q.invocations;
 533       }
 534    }
 535
 536    if (q.flags.q.early_fragment_tests) {
 537       state->fs_early_fragment_tests = true;
 538    }
 539
 540    if (this->flags.q.vertex_spacing) {
 541       if (q.flags.q.vertex_spacing &&
 542           this->vertex_spacing != q.vertex_spacing) {
 543          _mesa_glsl_error(loc, state,
 544                           "conflicting vertex spacing specified");
 545       }
 546    } else if (q.flags.q.vertex_spacing) {
 547       this->flags.q.vertex_spacing = 1;
 548       this->vertex_spacing = q.vertex_spacing;
 549    }
 550
 551    if (this->flags.q.ordering) {
 552       if (q.flags.q.ordering &&
 553           this->ordering != q.ordering) {
 554          _mesa_glsl_error(loc, state,
 555                           "conflicting ordering specified");
 556       }
 557    } else if (q.flags.q.ordering) {
 558       this->flags.q.ordering = 1;
 559       this->ordering = q.ordering;
 560    }
 561
 562    if (this->flags.q.point_mode) {
 563       if (q.flags.q.point_mode &&
 564           this->point_mode != q.point_mode) {
 565          _mesa_glsl_error(loc, state,
 566                           "conflicting point mode specified");
 567       }
 568    } else if (q.flags.q.point_mode) {
 569       this->flags.q.point_mode = 1;
 570       this->point_mode = q.point_mode;
 571    }
 572
 573    if (create_node) {
 574       if (create_gs_ast) {
 575          node = new(mem_ctx) ast_gs_input_layout(*loc, q.prim_type);
 576       } else if (create_cs_ast) {
 577          node = new(mem_ctx) ast_cs_input_layout(*loc, q.local_size);
 578       }
 579    }
 580
 581    return true;
 582 }
 583
 584 bool
 585 ast_layout_expression::process_qualifier_constant(struct _mesa_glsl_parse_state *state,
 586                                                   const char *qual_indentifier,
 587                                                   unsigned *value,
 588                                                   bool can_be_zero)
 589 {
 590    int min_value = 0;
 591    bool first_pass = true;
 592    *value = 0;
 593
 594    if (!can_be_zero)
 595       min_value = 1;
 596
 597    for (exec_node *node = layout_const_expressions.head;
 598            !node->is_tail_sentinel(); node = node->next) {
 599
 600       exec_list dummy_instructions;
 601       ast_node *const_expression = exec_node_data(ast_node, node, link);
 602
 603       ir_rvalue *const ir = const_expression->hir(&dummy_instructions, state);
 604
 605       ir_constant *const const_int = ir->constant_expression_value();
 606       if (const_int == NULL || !const_int->type->is_integer()) {
 607          YYLTYPE loc = const_expression->get_location();
 608          _mesa_glsl_error(&loc, state, "%s must be an integral constant "
 609                           "expression", qual_indentifier);
 610          return false;
 611       }
 612
 613       if (const_int->value.i[0] < min_value) {
 614          YYLTYPE loc = const_expression->get_location();
 615          _mesa_glsl_error(&loc, state, "%s layout qualifier is invalid "
 616                           "(%d < %d)", qual_indentifier,
 617                           const_int->value.i[0], min_value);
 618          return false;
 619       }
 620
 621       if (!first_pass && *value != const_int->value.u[0]) {
 622          YYLTYPE loc = const_expression->get_location();
 623          _mesa_glsl_error(&loc, state, "%s layout qualifier does not "
 624                           "match previous declaration (%d vs %d)",
 625                           qual_indentifier, *value, const_int->value.i[0]);
 626          return false;
 627       } else {
 628          first_pass = false;
 629          *value = const_int->value.u[0];
 630       }
 631
 632       /* If the location is const (and we've verified that
 633        * it is) then no instructions should have been emitted
 634        * when we converted it to HIR. If they were emitted,
 635        * then either the location isn't const after all, or
 636        * we are emitting unnecessary instructions.
 637        */
 638       assert(dummy_instructions.is_empty());
 639    }
 640
 641    return true;
 642 }
 643
 644 bool
 645 process_qualifier_constant(struct _mesa_glsl_parse_state *state,
 646                            YYLTYPE *loc,
 647                            const char *qual_indentifier,
 648                            ast_expression *const_expression,
 649                            unsigned *value)
 650 {
 651    exec_list dummy_instructions;
 652
 653    if (const_expression == NULL) {
 654       *value = 0;
 655       return true;
 656    }
 657
 658    ir_rvalue *const ir = const_expression->hir(&dummy_instructions, state);
 659
 660    ir_constant *const const_int = ir->constant_expression_value();
 661    if (const_int == NULL || !const_int->type->is_integer()) {
 662       _mesa_glsl_error(loc, state, "%s must be an integral constant "
 663                        "expression", qual_indentifier);
 664       return false;
 665    }
 666
 667    if (const_int->value.i[0] < 0) {
 668       _mesa_glsl_error(loc, state, "%s layout qualifier is invalid (%d < 0)",
 669                        qual_indentifier, const_int->value.u[0]);
 670       return false;
 671    }
 672
 673    /* If the location is const (and we've verified that
 674     * it is) then no instructions should have been emitted
 675     * when we converted it to HIR. If they were emitted,
 676     * then either the location isn't const after all, or
 677     * we are emitting unnecessary instructions.
 678     */
 679    assert(dummy_instructions.is_empty());
 680
 681    *value = const_int->value.u[0];
 682    return true;
 683 }