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