src/glsl/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_BOOL:
  39       /* There is no implicit conversion to or from integer types or bool.
  40        */
  41       if ((a->is_integer() != b->is_integer())
  42           || (a->is_boolean() != b->is_boolean()))
  43          return -1;
  44
  45       /* FALLTHROUGH */
  46
  47    case GLSL_TYPE_FLOAT:
  48       if ((a->vector_elements != b->vector_elements)
  49           || (a->matrix_columns != b->matrix_columns))
  50          return -1;
  51
  52       return 1;
  53
  54    case GLSL_TYPE_SAMPLER:
  55    case GLSL_TYPE_STRUCT:
  56       /* Samplers and structures must match exactly.
  57        */
  58       return -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          score = type_compare(actual->type, param->type);
 130          break;
 131
 132       case ir_var_inout:
 133          /* Since there are no bi-directional automatic conversions (e.g.,
 134           * there is int -> float but no float -> int), inout parameters must
 135           * be exact matches.
 136           */
 137          score = (type_compare(actual->type, param->type) == 0) ? 0 : -1;
 138          break;
 139       }
 140
 141       if (score < 0)
 142          return -1;
 143
 144       total_score += score;
 145    }
 146
 147    /* If all of the parameters from the other parameter list have been
 148     * exhausted, the lists have different length and, by definition, do not
 149     * match.
 150     */
 151    if (iter_b.has_next())
 152       return -1;
 153
 154    return total_score;
 155 }
 156
 157
 158 ir_function_signature *
 159 ir_function::matching_signature(exec_list *actual_parameters)
 160 {
 161    ir_function_signature *match = NULL;
 162
 163    foreach_iter(exec_list_iterator, iter, signatures) {
 164       ir_function_signature *const sig =
 165          (ir_function_signature *) iter.get();
 166
 167       const int score = parameter_lists_match(& sig->parameters,
 168                                               actual_parameters);
 169
 170       if (score == 0)
 171          return sig;
 172
 173       if (score > 0) {
 174          if (match != NULL)
 175             return NULL;
 176
 177          match = sig;
 178       }
 179    }
 180
 181    return match;
 182 }
 183
 184
 185 static bool
 186 parameter_lists_match_exact(exec_list *list_a, exec_list *list_b)
 187 {
 188    exec_list_iterator iter_a = list_a->iterator();
 189    exec_list_iterator iter_b = list_b->iterator();
 190
 191    while (iter_a.has_next() && iter_b.has_next()) {
 192       ir_variable *a = (ir_variable *)iter_a.get();
 193       ir_variable *b = (ir_variable *)iter_b.get();
 194
 195       /* If the types of the parameters do not match, the parameters lists
 196        * are different.
 197        */
 198       if (a->type != b->type)
 199          return false;
 200
 201       iter_a.next();
 202       iter_b.next();
 203    }
 204
 205    /* Unless both lists are exhausted, they differ in length and, by
 206     * definition, do not match.
 207     */
 208    if (iter_a.has_next() != iter_b.has_next())
 209       return false;
 210
 211    return true;
 212 }
 213
 214 ir_function_signature *
 215 ir_function::exact_matching_signature(exec_list *actual_parameters)
 216 {
 217    foreach_iter(exec_list_iterator, iter, signatures) {
 218       ir_function_signature *const sig =
 219          (ir_function_signature *) iter.get();
 220
 221       if (parameter_lists_match_exact(&sig->parameters, actual_parameters))
 222          return sig;
 223    }
 224    return NULL;
 225 }