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      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_VOID:
     74    case GLSL_TYPE_ERROR:
     75    default:
     76       /* These are all error conditions.  It is invalid for a parameter to
     77        * a function to be declared as error, void, or a function.
     78        */
     79       return -1;
     80    }
     81 
     82    /* This point should be unreachable.
     83     */
     84    assert(0);
     85 }
     86 
     87 
     88 static int
     89 parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
     90 {
     91    const exec_node *node_a = list_a->head;
     92    const exec_node *node_b = list_b->head;
     93    int total_score = 0;
     94 
     95    for (/* empty */
     96 	; !node_a->is_tail_sentinel()
     97 	; node_a = node_a->next, node_b = node_b->next) {
     98       /* If all of the parameters from the other parameter list have been
     99        * exhausted, the lists have different length and, by definition,
    100        * do not match.
    101        */
    102       if (node_b->is_tail_sentinel())
    103 	 return -1;
    104 
    105 
    106       const ir_variable *const param = (ir_variable *) node_a;
    107       const ir_instruction *const actual = (ir_instruction *) node_b;
    108 
    109       /* Determine whether or not the types match.  If the types are an
    110        * exact match, the match score is zero.  If the types don't match
    111        * but the actual parameter can be coerced to the type of the declared
    112        * parameter, the match score is one.
    113        */
    114       int score;
    115       switch ((enum ir_variable_mode)(param->mode)) {
    116       case ir_var_auto:
    117       case ir_var_uniform:
    118       case ir_var_temporary:
    119 	 /* These are all error conditions.  It is invalid for a parameter to
    120 	  * a function to be declared as auto (not in, out, or inout) or
    121 	  * as uniform.
    122 	  */
    123 	 assert(0);
    124 	 return -1;
    125 
    126       case ir_var_in:
    127 	 score = type_compare(param->type, actual->type);
    128 	 break;
    129 
    130       case ir_var_out:
    131 	 score = type_compare(actual->type, param->type);
    132 	 break;
    133 
    134       case ir_var_inout:
    135 	 /* Since there are no bi-directional automatic conversions (e.g.,
    136 	  * there is int -> float but no float -> int), inout parameters must
    137 	  * be exact matches.
    138 	  */
    139 	 score = (type_compare(actual->type, param->type) == 0) ? 0 : -1;
    140 	 break;
    141 
    142       default:
    143 	 assert(false);
    144       }
    145 
    146       if (score < 0)
    147 	 return -1;
    148 
    149       total_score += score;
    150    }
    151 
    152    /* If all of the parameters from the other parameter list have been
    153     * exhausted, the lists have different length and, by definition, do not
    154     * match.
    155     */
    156    if (!node_b->is_tail_sentinel())
    157       return -1;
    158 
    159    return total_score;
    160 }
    161 
    162 
    163 ir_function_signature *
    164 ir_function::matching_signature(const exec_list *actual_parameters)
    165 {
    166    ir_function_signature *match = NULL;
    167 
    168    foreach_iter(exec_list_iterator, iter, signatures) {
    169       ir_function_signature *const sig =
    170 	 (ir_function_signature *) iter.get();
    171 
    172       const int score = parameter_lists_match(& sig->parameters,
    173 					      actual_parameters);
    174 
    175       if (score == 0)
    176 	 return sig;
    177 
    178       if (score > 0) {
    179 	 if (match != NULL)
    180 	    return NULL;
    181 
    182 	 match = sig;
    183       }
    184    }
    185 
    186    return match;
    187 }
    188 
    189 
    190 static bool
    191 parameter_lists_match_exact(const exec_list *list_a, const exec_list *list_b)
    192 {
    193    const exec_node *node_a = list_a->head;
    194    const exec_node *node_b = list_b->head;
    195 
    196    for (/* empty */
    197 	; !node_a->is_tail_sentinel() && !node_b->is_tail_sentinel()
    198 	; node_a = node_a->next, node_b = node_b->next) {
    199       ir_variable *a = (ir_variable *) node_a;
    200       ir_variable *b = (ir_variable *) node_b;
    201 
    202       /* If the types of the parameters do not match, the parameters lists
    203        * are different.
    204        */
    205       if (a->type != b->type)
    206          return false;
    207    }
    208 
    209    /* Unless both lists are exhausted, they differ in length and, by
    210     * definition, do not match.
    211     */
    212    return (node_a->is_tail_sentinel() == node_b->is_tail_sentinel());
    213 }
    214 
    215 ir_function_signature *
    216 ir_function::exact_matching_signature(const exec_list *actual_parameters)
    217 {
    218    foreach_iter(exec_list_iterator, iter, signatures) {
    219       ir_function_signature *const sig =
    220 	 (ir_function_signature *) iter.get();
    221 
    222       if (parameter_lists_match_exact(&sig->parameters, actual_parameters))
    223 	 return sig;
    224    }
    225    return NULL;
    226 }
    227