ir_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 "glsl_types.h"
  25 #include "ir.h"
  26
  27 int
  28 type_compare(const glsl_type *a, const glsl_type *b)
  29 {
  30    switch (a->base_type) {
  31    case GLSL_TYPE_UINT:
  32    case GLSL_TYPE_INT:
  33    case GLSL_TYPE_FLOAT:
  34    case GLSL_TYPE_BOOL:
  35       if ((a->vector_elements != b->vector_elements)
  36           || (a->matrix_rows != b->matrix_rows))
  37          return -1;
  38
  39       if (a->base_type == b->base_type)
  40          return 0;
  41
  42       /* There is no implicit conversion to or from bool.
  43        */
  44       if ((a->base_type == GLSL_TYPE_BOOL)
  45           || (b->base_type == GLSL_TYPE_BOOL))
  46          return -1;
  47
  48       return 1;
  49
  50    case GLSL_TYPE_SAMPLER:
  51       return ((a->sampler_dimensionality == b->sampler_dimensionality)
  52               && (a->sampler_shadow == b->sampler_shadow)
  53               && (a->sampler_array == b->sampler_array)
  54               && (a->sampler_type == b->sampler_type))
  55          ? 0 : -1;
  56
  57    case GLSL_TYPE_STRUCT:
  58       return (strcmp(a->name, b->name) == 0) ? 0 : -1;
  59
  60    case GLSL_TYPE_ARRAY:
  61       if ((b->base_type != GLSL_TYPE_ARRAY)
  62           || (a->length != b->length))
  63          return -1;
  64
  65       /* From GLSL 1.50 spec, page 27 (page 33 of the PDF):
  66        *    "There are no implicit array or structure conversions."
  67        *
  68        * If the comparison of the array element types detects that a conversion
  69        * would be required, the array types do not match.
  70        */
  71       return (type_compare(a->fields.array, b->fields.array) == 0) ? 0 : -1;
  72
  73    case GLSL_TYPE_FUNCTION:
  74    case GLSL_TYPE_VOID:
  75    case GLSL_TYPE_ERROR:
  76    default:
  77       /* These are all error conditions.  It is invalid for a parameter to
  78        * a function to be declared as error, void, or a function.
  79        */
  80       return -1;
  81    }
  82
  83    /* This point should be unreachable.
  84     */
  85    assert(0);
  86 }
  87
  88
  89 static int
  90 parameter_lists_match(exec_list *list_a, exec_list *list_b)
  91 {
  92    exec_list_iterator iter_a = list_a->iterator();
  93    exec_list_iterator iter_b = list_b->iterator();
  94    int total_score = 0;
  95
  96    for (/* empty */ ; iter_a.has_next(); iter_a.next(), iter_b.next()) {
  97       /* If all of the parameters from the other parameter list have been
  98        * exhausted, the lists have different length and, by definition,
  99        * do not match.
 100        */
 101       if (!iter_b.has_next())
 102          return -1;
 103
 104
 105       const ir_variable *const param = (ir_variable *) iter_a.get();
 106       const ir_instruction *const actual = (ir_instruction *) iter_b.get();
 107
 108       /* Determine whether or not the types match.  If the types are an
 109        * exact match, the match score is zero.  If the types don't match
 110        * but the actual parameter can be coerced to the type of the declared
 111        * parameter, the match score is one.
 112        */
 113       int score;
 114       switch ((enum ir_variable_mode)(param->mode)) {
 115       case ir_var_auto:
 116       case ir_var_uniform:
 117          /* These are all error conditions.  It is invalid for a parameter to
 118           * a function to be declared as auto (not in, out, or inout) or
 119           * as uniform.
 120           */
 121          assert(0);
 122          return -1;
 123
 124       case ir_var_in:
 125          score = type_compare(param->type, actual->type);
 126          break;
 127
 128       case ir_var_out:
 129          /* FINISHME: Make sure that actual is a valid lvalue. */
 130          score = type_compare(actual->type, param->type);
 131          break;
 132
 133       case ir_var_inout:
 134          /* FINISHME: Make sure that actual is a valid lvalue. */
 135
 136          /* Since there are no bi-directional automatic conversions (e.g.,
 137           * there is int -> float but no float -> int), inout parameters must
 138           * be exact matches.
 139           */
 140          score = (type_compare(actual->type, param->type) == 0) ? 0 : -1;
 141          break;
 142       }
 143
 144       if (score < 0)
 145          return -1;
 146
 147       total_score += score;
 148    }
 149
 150    /* If all of the parameters from the other parameter list have been
 151     * exhausted, the lists have different length and, by definition, do not
 152     * match.
 153     */
 154    if (iter_b.has_next())
 155       return -1;
 156
 157    return total_score;
 158 }
 159
 160
 161 const ir_function_signature *
 162 ir_function::matching_signature(exec_list *actual_parameters)
 163 {
 164    ir_function_signature *match = NULL;
 165
 166    foreach_iter(exec_list_iterator, iter, signatures) {
 167       ir_function_signature *const sig =
 168          (ir_function_signature *) iter.get();
 169
 170       const int score = parameter_lists_match(& sig->parameters,
 171                                               actual_parameters);
 172
 173       if (score == 0)
 174          return sig;
 175
 176       if (score > 0) {
 177          if (match != NULL)
 178             return NULL;
 179
 180          match = sig;
 181       }
 182    }
 183
 184    return match;
 185 }