ast_function.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 <cstdio>
  25 #include "glsl_symbol_table.h"
  26 #include "ast.h"
  27 #include "glsl_types.h"
  28 #include "ir.h"
  29
  30 static unsigned
  31 process_parameters(exec_list *instructions, exec_list *actual_parameters,
  32                    exec_list *parameters,
  33                    struct _mesa_glsl_parse_state *state)
  34 {
  35    unsigned count = 0;
  36
  37    foreach_list (n, parameters) {
  38       ast_node *const ast = exec_node_data(ast_node, n, link);
  39       ir_rvalue *result = ast->hir(instructions, state);
  40
  41       ir_constant *const constant = result->constant_expression_value();
  42       if (constant != NULL)
  43          result = constant;
  44
  45       actual_parameters->push_tail(result);
  46       count++;
  47    }
  48
  49    return count;
  50 }
  51
  52
  53 static ir_rvalue *
  54 process_call(exec_list *instructions, ir_function *f,
  55              YYLTYPE *loc, exec_list *actual_parameters,
  56              struct _mesa_glsl_parse_state *state)
  57 {
  58    const ir_function_signature *sig =
  59       f->matching_signature(actual_parameters);
  60
  61    /* The instructions param will be used when the FINISHMEs below are done */
  62    (void) instructions;
  63
  64    if (sig != NULL) {
  65       /* Verify that 'out' and 'inout' actual parameters are lvalues.  This
  66        * isn't done in ir_function::matching_signature because that function
  67        * cannot generate the necessary diagnostics.
  68        */
  69       exec_list_iterator actual_iter = actual_parameters->iterator();
  70       exec_list_iterator formal_iter = sig->parameters.iterator();
  71
  72       while (actual_iter.has_next()) {
  73          ir_rvalue *actual = (ir_rvalue *) actual_iter.get();
  74          ir_variable *formal = (ir_variable *) formal_iter.get();
  75
  76          assert(actual != NULL);
  77          assert(formal != NULL);
  78
  79          if ((formal->mode == ir_var_out)
  80              || (formal->mode == ir_var_inout)) {
  81             if (! actual->is_lvalue()) {
  82                /* FINISHME: Log a better diagnostic here.  There is no way
  83                 * FINISHME: to tell the user which parameter is invalid.
  84                 */
  85                _mesa_glsl_error(loc, state, "`%s' parameter is not lvalue",
  86                                 (formal->mode == ir_var_out) ? "out" : "inout");
  87             }
  88          }
  89
  90          actual_iter.next();
  91          formal_iter.next();
  92       }
  93
  94       /* FINISHME: The list of actual parameters needs to be modified to
  95        * FINISHME: include any necessary conversions.
  96        */
  97       return new ir_call(sig, actual_parameters);
  98    } else {
  99       /* FINISHME: Log a better error message here.  G++ will show the types
 100        * FINISHME: of the actual parameters and the set of candidate
 101        * FINISHME: functions.  A different error should also be logged when
 102        * FINISHME: multiple functions match.
 103        */
 104       _mesa_glsl_error(loc, state, "no matching function for call to `%s'",
 105                        f->name);
 106       return ir_call::get_error_instruction();
 107    }
 108 }
 109
 110
 111 static ir_rvalue *
 112 match_function_by_name(exec_list *instructions, const char *name,
 113                        YYLTYPE *loc, exec_list *actual_parameters,
 114                        struct _mesa_glsl_parse_state *state)
 115 {
 116    ir_function *f = state->symbols->get_function(name);
 117
 118    if (f == NULL) {
 119       _mesa_glsl_error(loc, state, "function `%s' undeclared", name);
 120       return ir_call::get_error_instruction();
 121    }
 122
 123    /* Once we've determined that the function being called might exist, try
 124     * to find an overload of the function that matches the parameters.
 125     */
 126    return process_call(instructions, f, loc, actual_parameters, state);
 127 }
 128
 129
 130 /**
 131  * Perform automatic type conversion of constructor parameters
 132  */
 133 static ir_rvalue *
 134 convert_component(ir_rvalue *src, const glsl_type *desired_type)
 135 {
 136    const unsigned a = desired_type->base_type;
 137    const unsigned b = src->type->base_type;
 138    ir_expression *result = NULL;
 139
 140    if (src->type->is_error())
 141       return src;
 142
 143    assert(a <= GLSL_TYPE_BOOL);
 144    assert(b <= GLSL_TYPE_BOOL);
 145
 146    if ((a == b) || (src->type->is_integer() && desired_type->is_integer()))
 147       return src;
 148
 149    switch (a) {
 150    case GLSL_TYPE_UINT:
 151    case GLSL_TYPE_INT:
 152       if (b == GLSL_TYPE_FLOAT)
 153          result = new ir_expression(ir_unop_f2i, desired_type, src, NULL);
 154       else {
 155          assert(b == GLSL_TYPE_BOOL);
 156          result = new ir_expression(ir_unop_b2i, desired_type, src, NULL);
 157       }
 158       break;
 159    case GLSL_TYPE_FLOAT:
 160       switch (b) {
 161       case GLSL_TYPE_UINT:
 162          result = new ir_expression(ir_unop_u2f, desired_type, src, NULL);
 163          break;
 164       case GLSL_TYPE_INT:
 165          result = new ir_expression(ir_unop_i2f, desired_type, src, NULL);
 166          break;
 167       case GLSL_TYPE_BOOL:
 168          result = new ir_expression(ir_unop_b2f, desired_type, src, NULL);
 169          break;
 170       }
 171       break;
 172    case GLSL_TYPE_BOOL: {
 173       int z = 0;
 174       ir_constant *const zero = new ir_constant(src->type, &z);
 175
 176       result = new ir_expression(ir_binop_nequal, desired_type, src, zero);
 177    }
 178    }
 179
 180    assert(result != NULL);
 181
 182    ir_constant *const constant = result->constant_expression_value();
 183    return (constant != NULL) ? (ir_rvalue *) constant : (ir_rvalue *) result;
 184 }
 185
 186
 187 /**
 188  * Dereference a specific component from a scalar, vector, or matrix
 189  */
 190 static ir_rvalue *
 191 dereference_component(ir_rvalue *src, unsigned component)
 192 {
 193    assert(component < src->type->components());
 194
 195    /* If the source is a constant, just create a new constant instead of a
 196     * dereference of the existing constant.
 197     */
 198    ir_constant *constant = src->as_constant();
 199    if (constant)
 200       return new ir_constant(constant, component);
 201
 202    if (src->type->is_scalar()) {
 203       return src;
 204    } else if (src->type->is_vector()) {
 205       return new ir_swizzle(src, component, 0, 0, 0, 1);
 206    } else {
 207       assert(src->type->is_matrix());
 208
 209       /* Dereference a row of the matrix, then call this function again to get
 210        * a specific element from that row.
 211        */
 212       const int c = component / src->type->column_type()->vector_elements;
 213       const int r = component % src->type->column_type()->vector_elements;
 214       ir_constant *const col_index = new ir_constant(glsl_type::int_type, &c);
 215       ir_dereference *const col = new ir_dereference_array(src, col_index);
 216
 217       col->type = src->type->column_type();
 218
 219       return dereference_component(col, r);
 220    }
 221
 222    assert(!"Should not get here.");
 223    return NULL;
 224 }
 225
 226
 227 static ir_rvalue *
 228 process_array_constructor(exec_list *instructions,
 229                           const glsl_type *constructor_type,
 230                           YYLTYPE *loc, exec_list *parameters,
 231                           struct _mesa_glsl_parse_state *state)
 232 {
 233    /* Array constructors come in two forms: sized and unsized.  Sized array
 234     * constructors look like 'vec4[2](a, b)', where 'a' and 'b' are vec4
 235     * variables.  In this case the number of parameters must exactly match the
 236     * specified size of the array.
 237     *
 238     * Unsized array constructors look like 'vec4[](a, b)', where 'a' and 'b'
 239     * are vec4 variables.  In this case the size of the array being constructed
 240     * is determined by the number of parameters.
 241     *
 242     * From page 52 (page 58 of the PDF) of the GLSL 1.50 spec:
 243     *
 244     *    "There must be exactly the same number of arguments as the size of
 245     *    the array being constructed. If no size is present in the
 246     *    constructor, then the array is explicitly sized to the number of
 247     *    arguments provided. The arguments are assigned in order, starting at
 248     *    element 0, to the elements of the constructed array. Each argument
 249     *    must be the same type as the element type of the array, or be a type
 250     *    that can be converted to the element type of the array according to
 251     *    Section 4.1.10 "Implicit Conversions.""
 252     */
 253    exec_list actual_parameters;
 254    const unsigned parameter_count =
 255       process_parameters(instructions, &actual_parameters, parameters, state);
 256
 257    if ((parameter_count == 0)
 258        || ((constructor_type->length != 0)
 259            && (constructor_type->length != parameter_count))) {
 260       const unsigned min_param = (constructor_type->length == 0)
 261          ? 1 : constructor_type->length;
 262
 263       _mesa_glsl_error(loc, state, "array constructor must have %s %u "
 264                        "parameter%s",
 265                        (constructor_type->length != 0) ? "at least" : "exactly",
 266                        min_param, (min_param <= 1) ? "" : "s");
 267       return ir_call::get_error_instruction();
 268    }
 269
 270    if (constructor_type->length == 0) {
 271       constructor_type =
 272          glsl_type::get_array_instance(constructor_type->element_type(),
 273                                        parameter_count);
 274       assert(constructor_type != NULL);
 275       assert(constructor_type->length == parameter_count);
 276    }
 277
 278    ir_function *f = state->symbols->get_function(constructor_type->name);
 279
 280    /* If the constructor for this type of array does not exist, generate the
 281     * prototype and add it to the symbol table.
 282     */
 283    if (f == NULL) {
 284       f = constructor_type->generate_constructor(state->symbols);
 285    }
 286
 287    ir_rvalue *const r =
 288       process_call(instructions, f, loc, &actual_parameters, state);
 289
 290    assert(r != NULL);
 291    assert(r->type->is_error() || (r->type == constructor_type));
 292
 293    return r;
 294 }
 295
 296
 297 /**
 298  * Try to convert a record constructor to a constant expression
 299  */
 300 static ir_constant *
 301 constant_record_constructor(const glsl_type *constructor_type,
 302                             YYLTYPE *loc, exec_list *parameters,
 303                             struct _mesa_glsl_parse_state *state)
 304 {
 305    bool all_parameters_are_constant = true;
 306
 307    exec_node *node = parameters->head;
 308    for (unsigned i = 0; i < constructor_type->length; i++) {
 309       ir_instruction *ir = (ir_instruction *) node;
 310
 311       if (node->is_tail_sentinal()) {
 312          _mesa_glsl_error(loc, state,
 313                           "insufficient parameters to constructor for `%s'",
 314                           constructor_type->name);
 315          return NULL;
 316       }
 317
 318       if (ir->type != constructor_type->fields.structure[i].type) {
 319          _mesa_glsl_error(loc, state,
 320                           "parameter type mismatch in constructor for `%s' "
 321                           " (%s vs %s)",
 322                           constructor_type->name,
 323                           ir->type->name,
 324                           constructor_type->fields.structure[i].type->name);
 325          return NULL;
 326       }
 327
 328       if (ir->as_constant() == NULL)
 329          all_parameters_are_constant = false;
 330
 331       node = node->next;
 332    }
 333
 334    if (!all_parameters_are_constant)
 335       return NULL;
 336
 337    return new ir_constant(constructor_type, parameters);
 338 }
 339
 340
 341 /**
 342  * Generate data for a constant matrix constructor w/a single scalar parameter
 343  *
 344  * Matrix constructors in GLSL can be passed a single scalar of the
 345  * approriate type.  In these cases, the resulting matrix is the identity
 346  * matrix multipled by the specified scalar.  This function generates data for
 347  * that matrix.
 348  *
 349  * \param type         Type of the desired matrix.
 350  * \param initializer  Scalar value used to initialize the matrix diagonal.
 351  * \param data         Location to store the resulting matrix.
 352  */
 353 void
 354 generate_constructor_matrix(const glsl_type *type, ir_constant *initializer,
 355                             ir_constant_data *data)
 356 {
 357    switch (type->base_type) {
 358    case GLSL_TYPE_UINT:
 359    case GLSL_TYPE_INT:
 360       for (unsigned i = 0; i < type->components(); i++)
 361          data->u[i] = 0;
 362
 363       for (unsigned i = 0; i < type->matrix_columns; i++) {
 364          /* The array offset of the ith row and column of the matrix.
 365           */
 366          const unsigned idx = (i * type->vector_elements) + i;
 367
 368          data->u[idx] = initializer->value.u[0];
 369       }
 370       break;
 371
 372    case GLSL_TYPE_FLOAT:
 373       for (unsigned i = 0; i < type->components(); i++)
 374          data->f[i] = 0;
 375
 376       for (unsigned i = 0; i < type->matrix_columns; i++) {
 377          /* The array offset of the ith row and column of the matrix.
 378           */
 379          const unsigned idx = (i * type->vector_elements) + i;
 380
 381          data->f[idx] = initializer->value.f[0];
 382       }
 383
 384       break;
 385
 386    default:
 387       assert(!"Should not get here.");
 388       break;
 389    }
 390 }
 391
 392
 393 /**
 394  * Generate data for a constant vector constructor w/a single scalar parameter
 395  *
 396  * Vector constructors in GLSL can be passed a single scalar of the
 397  * approriate type.  In these cases, the resulting vector contains the specified
 398  * value in all components.  This function generates data for that vector.
 399  *
 400  * \param type         Type of the desired vector.
 401  * \param initializer  Scalar value used to initialize the vector.
 402  * \param data         Location to store the resulting vector data.
 403  */
 404 void
 405 generate_constructor_vector(const glsl_type *type, ir_constant *initializer,
 406                             ir_constant_data *data)
 407 {
 408    switch (type->base_type) {
 409    case GLSL_TYPE_UINT:
 410    case GLSL_TYPE_INT:
 411       for (unsigned i = 0; i < type->components(); i++)
 412          data->u[i] = initializer->value.u[0];
 413
 414       break;
 415
 416    case GLSL_TYPE_FLOAT:
 417       for (unsigned i = 0; i < type->components(); i++)
 418          data->f[i] = initializer->value.f[0];
 419
 420       break;
 421
 422    case GLSL_TYPE_BOOL:
 423       for (unsigned i = 0; i < type->components(); i++)
 424          data->b[i] = initializer->value.b[0];
 425
 426       break;
 427
 428    default:
 429       assert(!"Should not get here.");
 430       break;
 431    }
 432 }
 433
 434
 435 ir_rvalue *
 436 ast_function_expression::hir(exec_list *instructions,
 437                              struct _mesa_glsl_parse_state *state)
 438 {
 439    /* There are three sorts of function calls.
 440     *
 441     * 1. contstructors - The first subexpression is an ast_type_specifier.
 442     * 2. methods - Only the .length() method of array types.
 443     * 3. functions - Calls to regular old functions.
 444     *
 445     * Method calls are actually detected when the ast_field_selection
 446     * expression is handled.
 447     */
 448    if (is_constructor()) {
 449       const ast_type_specifier *type = (ast_type_specifier *) subexpressions[0];
 450       YYLTYPE loc = type->get_location();
 451       const char *name;
 452
 453       const glsl_type *const constructor_type = type->glsl_type(& name, state);
 454
 455
 456       /* Constructors for samplers are illegal.
 457        */
 458       if (constructor_type->is_sampler()) {
 459          _mesa_glsl_error(& loc, state, "cannot construct sampler type `%s'",
 460                           constructor_type->name);
 461          return ir_call::get_error_instruction();
 462       }
 463
 464       if (constructor_type->is_array()) {
 465          if (state->language_version <= 110) {
 466             _mesa_glsl_error(& loc, state,
 467                              "array constructors forbidden in GLSL 1.10");
 468             return ir_call::get_error_instruction();
 469          }
 470
 471          return process_array_constructor(instructions, constructor_type,
 472                                           & loc, &this->expressions, state);
 473       }
 474
 475       /* There are two kinds of constructor call.  Constructors for built-in
 476        * language types, such as mat4 and vec2, are free form.  The only
 477        * requirement is that the parameters must provide enough values of the
 478        * correct scalar type.  Constructors for arrays and structures must
 479        * have the exact number of parameters with matching types in the
 480        * correct order.  These constructors follow essentially the same type
 481        * matching rules as functions.
 482        */
 483       if (constructor_type->is_numeric() || constructor_type->is_boolean()) {
 484          /* Constructing a numeric type has a couple steps.  First all values
 485           * passed to the constructor are broken into individual parameters
 486           * and type converted to the base type of the thing being constructed.
 487           *
 488           * At that point we have some number of values that match the base
 489           * type of the thing being constructed.  Now the constructor can be
 490           * treated like a function call.  Each numeric type has a small set
 491           * of constructor functions.  The set of new parameters will either
 492           * match one of those functions or the original constructor is
 493           * invalid.
 494           */
 495          const glsl_type *const base_type = constructor_type->get_base_type();
 496
 497          /* Total number of components of the type being constructed.
 498           */
 499          const unsigned type_components = constructor_type->components();
 500
 501          /* Number of components from parameters that have actually been
 502           * consumed.  This is used to perform several kinds of error checking.
 503           */
 504          unsigned components_used = 0;
 505
 506          unsigned matrix_parameters = 0;
 507          unsigned nonmatrix_parameters = 0;
 508          exec_list actual_parameters;
 509
 510          bool all_parameters_are_constant = true;
 511
 512          assert(!this->expressions.is_empty());
 513
 514          foreach_list (n, &this->expressions) {
 515             ast_node *ast = exec_node_data(ast_node, n, link);
 516             ir_rvalue *result =
 517                ast->hir(instructions, state)->as_rvalue();
 518
 519             /* Attempt to convert the parameter to a constant valued expression.
 520              * After doing so, track whether or not all the parameters to the
 521              * constructor are trivially constant valued expressions.
 522              */
 523             ir_rvalue *const constant =
 524                result->constant_expression_value();
 525
 526             if (constant != NULL)
 527                result = constant;
 528             else
 529                all_parameters_are_constant = false;
 530
 531             /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
 532              *
 533              *    "It is an error to provide extra arguments beyond this
 534              *    last used argument."
 535              */
 536             if (components_used >= type_components) {
 537                _mesa_glsl_error(& loc, state, "too many parameters to `%s' "
 538                                 "constructor",
 539                                 constructor_type->name);
 540                return ir_call::get_error_instruction();
 541             }
 542
 543             if (!result->type->is_numeric() && !result->type->is_boolean()) {
 544                _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
 545                                 "non-numeric data type",
 546                                 constructor_type->name);
 547                return ir_call::get_error_instruction();
 548             }
 549
 550             /* Count the number of matrix and nonmatrix parameters.  This
 551              * is used below to enforce some of the constructor rules.
 552              */
 553             if (result->type->is_matrix())
 554                matrix_parameters++;
 555             else
 556                nonmatrix_parameters++;
 557
 558
 559             /* Process each of the components of the parameter.  Dereference
 560              * each component individually, perform any type conversions, and
 561              * add it to the parameter list for the constructor.
 562              */
 563             for (unsigned i = 0; i < result->type->components(); i++) {
 564                if (components_used >= type_components)
 565                   break;
 566
 567                ir_rvalue *const component =
 568                   convert_component(dereference_component(result, i),
 569                                     base_type);
 570
 571                /* All cases that could result in component->type being the
 572                 * error type should have already been caught above.
 573                 */
 574                assert(component->type == base_type);
 575
 576                if (component->as_constant() == NULL)
 577                   all_parameters_are_constant = false;
 578
 579                /* Don't actually generate constructor calls for scalars.
 580                 * Instead, do the usual component selection and conversion,
 581                 * and return the single component.
 582                 */
 583                if (constructor_type->is_scalar())
 584                   return component;
 585
 586                actual_parameters.push_tail(component);
 587                components_used++;
 588             }
 589          }
 590
 591          /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
 592           *
 593           *    "It is an error to construct matrices from other matrices. This
 594           *    is reserved for future use."
 595           */
 596          if ((state->language_version <= 110) && (matrix_parameters > 0)
 597              && constructor_type->is_matrix()) {
 598             _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
 599                              "matrix in GLSL 1.10",
 600                              constructor_type->name);
 601             return ir_call::get_error_instruction();
 602          }
 603
 604          /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
 605           *
 606           *    "If a matrix argument is given to a matrix constructor, it is
 607           *    an error to have any other arguments."
 608           */
 609          if ((matrix_parameters > 0)
 610              && ((matrix_parameters + nonmatrix_parameters) > 1)
 611              && constructor_type->is_matrix()) {
 612             _mesa_glsl_error(& loc, state, "for matrix `%s' constructor, "
 613                              "matrix must be only parameter",
 614                              constructor_type->name);
 615             return ir_call::get_error_instruction();
 616          }
 617
 618          /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
 619           *
 620           *    "In these cases, there must be enough components provided in the
 621           *    arguments to provide an initializer for every component in the
 622           *    constructed value."
 623           */
 624          if ((components_used < type_components) && (components_used != 1)) {
 625             _mesa_glsl_error(& loc, state, "too few components to construct "
 626                              "`%s'",
 627                              constructor_type->name);
 628             return ir_call::get_error_instruction();
 629          }
 630
 631          ir_function *f = state->symbols->get_function(constructor_type->name);
 632          if (f == NULL) {
 633             _mesa_glsl_error(& loc, state, "no constructor for type `%s'",
 634                              constructor_type->name);
 635             return ir_call::get_error_instruction();
 636          }
 637
 638          const ir_function_signature *sig =
 639             f->matching_signature(& actual_parameters);
 640          if (sig != NULL) {
 641             /* If all of the parameters are trivially constant, create a
 642              * constant representing the complete collection of parameters.
 643              */
 644             if (all_parameters_are_constant) {
 645                if (components_used >= type_components)
 646                   return new ir_constant(sig->return_type, & actual_parameters);
 647
 648                assert(sig->return_type->is_vector()
 649                       || sig->return_type->is_matrix());
 650
 651                /* Constructors with exactly one component are special for
 652                 * vectors and matrices.  For vectors it causes all elements of
 653                 * the vector to be filled with the value.  For matrices it
 654                 * causes the matrix to be filled with 0 and the diagonal to be
 655                 * filled with the value.
 656                 */
 657                ir_constant_data data;
 658                ir_constant *const initializer =
 659                   (ir_constant *) actual_parameters.head;
 660                if (sig->return_type->is_matrix())
 661                   generate_constructor_matrix(sig->return_type, initializer,
 662                                               &data);
 663                else
 664                   generate_constructor_vector(sig->return_type, initializer,
 665                                               &data);
 666
 667                return new ir_constant(sig->return_type, &data);
 668             } else
 669                return new ir_call(sig, & actual_parameters);
 670          } else {
 671             /* FINISHME: Log a better error message here.  G++ will show the
 672              * FINSIHME: types of the actual parameters and the set of
 673              * FINSIHME: candidate functions.  A different error should also be
 674              * FINSIHME: logged when multiple functions match.
 675              */
 676             _mesa_glsl_error(& loc, state, "no matching constructor for `%s'",
 677                              constructor_type->name);
 678             return ir_call::get_error_instruction();
 679          }
 680       }
 681
 682       return ir_call::get_error_instruction();
 683    } else {
 684       const ast_expression *id = subexpressions[0];
 685       YYLTYPE loc = id->get_location();
 686       exec_list actual_parameters;
 687
 688       process_parameters(instructions, &actual_parameters, &this->expressions,
 689                          state);
 690
 691       const glsl_type *const type =
 692          state->symbols->get_type(id->primary_expression.identifier);
 693
 694       if ((type != NULL) && type->is_record()) {
 695          ir_constant *constant =
 696             constant_record_constructor(type, &loc, &actual_parameters, state);
 697
 698          if (constant != NULL)
 699             return constant;
 700       }
 701
 702       return match_function_by_name(instructions,
 703                                     id->primary_expression.identifier, & loc,
 704                                     &actual_parameters, state);
 705    }
 706
 707    return ir_call::get_error_instruction();
 708 }