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(const exec_list *list_a, const exec_list *list_b)
  91 {
  92    const exec_node *node_a = list_a->head;
  93    const exec_node *node_b = list_b->head;
  94    int total_score = 0;
  95
  96    for (/* empty */
  97         ; !node_a->is_tail_sentinel()
  98         ; node_a = node_a->next, node_b = node_b->next) {
  99       /* If all of the parameters from the other parameter list have been
 100        * exhausted, the lists have different length and, by definition,
 101        * do not match.
 102        */
 103       if (node_b->is_tail_sentinel())
 104          return -1;
 105
 106
 107       const ir_variable *const param = (ir_variable *) node_a;
 108       const ir_instruction *const actual = (ir_instruction *) node_b;
 109
 110       /* Determine whether or not the types match.  If the types are an
 111        * exact match, the match score is zero.  If the types don't match
 112        * but the actual parameter can be coerced to the type of the declared
 113        * parameter, the match score is one.
 114        */
 115       int score;
 116       switch ((enum ir_variable_mode)(param->mode)) {
 117       case ir_var_auto:
 118       case ir_var_uniform:
 119       case ir_var_temporary:
 120          /* These are all error conditions.  It is invalid for a parameter to
 121           * a function to be declared as auto (not in, out, or inout) or
 122           * as uniform.
 123           */
 124          assert(0);
 125          return -1;
 126
 127       case ir_var_in:
 128          score = type_compare(param->type, actual->type);
 129          break;
 130
 131       case ir_var_out:
 132          score = type_compare(actual->type, param->type);
 133          break;
 134
 135       case ir_var_inout:
 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 (!node_b->is_tail_sentinel())
 155       return -1;
 156
 157    return total_score;
 158 }
 159
 160
 161 ir_function_signature *
 162 ir_function::matching_signature(const 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 }
 186
 187
 188 static bool
 189 parameter_lists_match_exact(const exec_list *list_a, const exec_list *list_b)
 190 {
 191    const exec_node *node_a = list_a->head;
 192    const exec_node *node_b = list_b->head;
 193
 194    for (/* empty */
 195         ; !node_a->is_tail_sentinel() && !node_b->is_tail_sentinel()
 196         ; node_a = node_a->next, node_b = node_b->next) {
 197       ir_variable *a = (ir_variable *) node_a;
 198       ir_variable *b = (ir_variable *) node_b;
 199
 200       /* If the types of the parameters do not match, the parameters lists
 201        * are different.
 202        */
 203       if (a->type != b->type)
 204          return false;
 205    }
 206
 207    /* Unless both lists are exhausted, they differ in length and, by
 208     * definition, do not match.
 209     */
 210    return (node_a->is_tail_sentinel() == node_b->is_tail_sentinel());
 211 }
 212
 213 ir_function_signature *
 214 ir_function::exact_matching_signature(const exec_list *actual_parameters)
 215 {
 216    foreach_iter(exec_list_iterator, iter, signatures) {
 217       ir_function_signature *const sig =
 218          (ir_function_signature *) iter.get();
 219
 220       if (parameter_lists_match_exact(&sig->parameters, actual_parameters))
 221          return sig;
 222    }
 223    return NULL;
 224 }