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/*

 * Copyright © 2010 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

#include "glsl_types.h"

#include "ir.h"

int

type_compare(const glsl_type *a, const glsl_type *b)

{

   /* If the types are the same, they trivially match.

    */

   if (a == b)

      return 0;

   switch (a->base_type) {

   case GLSL_TYPE_UINT:

   case GLSL_TYPE_INT:

   case GLSL_TYPE_BOOL:

      /* There is no implicit conversion to or from integer types or bool.

       */

      if ((a->is_integer() != b->is_integer())

	  || (a->is_boolean() != b->is_boolean()))

	 return -1;

      /* FALLTHROUGH */

   case GLSL_TYPE_FLOAT:

      if ((a->vector_elements != b->vector_elements)

	  || (a->matrix_columns != b->matrix_columns))

	 return -1;

      return 1;

   case GLSL_TYPE_SAMPLER:

   case GLSL_TYPE_STRUCT:

      /* Samplers and structures must match exactly.

       */

      return -1;

   case GLSL_TYPE_ARRAY:

      if ((b->base_type != GLSL_TYPE_ARRAY)

	  || (a->length != b->length))

	 return -1;

      /* From GLSL 1.50 spec, page 27 (page 33 of the PDF):

       *    "There are no implicit array or structure conversions."

       *

       * If the comparison of the array element types detects that a conversion

       * would be required, the array types do not match.

       */

      return (type_compare(a->fields.array, b->fields.array) == 0) ? 0 : -1;

   case GLSL_TYPE_VOID:

   case GLSL_TYPE_ERROR:

   default:

      /* These are all error conditions.  It is invalid for a parameter to

       * a function to be declared as error, void, or a function.

       */

      return -1;

   }

   /* This point should be unreachable.

    */

   assert(0);

}

static int

parameter_lists_match(const exec_list *list_a, const exec_list *list_b)

{

   const exec_node *node_a = list_a->head;

   const exec_node *node_b = list_b->head;

   int total_score = 0;

   for (/* empty */

	; !node_a->is_tail_sentinel()

	; node_a = node_a->next, node_b = node_b->next) {

      /* If all of the parameters from the other parameter list have been

       * exhausted, the lists have different length and, by definition,

       * do not match.

       */

      if (node_b->is_tail_sentinel())

	 return -1;

      const ir_variable *const param = (ir_variable *) node_a;

      const ir_instruction *const actual = (ir_instruction *) node_b;

      /* Determine whether or not the types match.  If the types are an

       * exact match, the match score is zero.  If the types don't match

       * but the actual parameter can be coerced to the type of the declared

       * parameter, the match score is one.

       */

      int score;

      switch ((enum ir_variable_mode)(param->mode)) {

      case ir_var_auto:

      case ir_var_uniform:

      case ir_var_temporary:

	 /* These are all error conditions.  It is invalid for a parameter to

	  * a function to be declared as auto (not in, out, or inout) or

	  * as uniform.

	  */

	 assert(0);

	 return -1;

      case ir_var_in:

	 score = type_compare(param->type, actual->type);

	 break;

      case ir_var_out:

	 score = type_compare(actual->type, param->type);

	 break;

      case ir_var_inout:

	 /* Since there are no bi-directional automatic conversions (e.g.,

	  * there is int -> float but no float -> int), inout parameters must

	  * be exact matches.

	  */

	 score = (type_compare(actual->type, param->type) == 0) ? 0 : -1;

	 break;

      default:

	 assert(false);

      }

      if (score < 0)

	 return -1;

      total_score += score;

   }

   /* If all of the parameters from the other parameter list have been

    * exhausted, the lists have different length and, by definition, do not

    * match.

    */

   if (!node_b->is_tail_sentinel())

      return -1;

   return total_score;

}

ir_function_signature *

ir_function::matching_signature(const exec_list *actual_parameters)

{

   ir_function_signature *match = NULL;

   foreach_iter(exec_list_iterator, iter, signatures) {

      ir_function_signature *const sig =

	 (ir_function_signature *) iter.get();

      const int score = parameter_lists_match(& sig->parameters,

					      actual_parameters);

      if (score == 0)

	 return sig;

      if (score > 0) {

	 if (match != NULL)

	    return NULL;

	 match = sig;

      }

   }

   return match;

}

static bool

parameter_lists_match_exact(const exec_list *list_a, const exec_list *list_b)

{

   const exec_node *node_a = list_a->head;

   const exec_node *node_b = list_b->head;

   for (/* empty */

	; !node_a->is_tail_sentinel() && !node_b->is_tail_sentinel()

	; node_a = node_a->next, node_b = node_b->next) {

      ir_variable *a = (ir_variable *) node_a;

      ir_variable *b = (ir_variable *) node_b;

      /* If the types of the parameters do not match, the parameters lists

       * are different.

       */

      if (a->type != b->type)

         return false;

   }

   /* Unless both lists are exhausted, they differ in length and, by

    * definition, do not match.

    */

   return (node_a->is_tail_sentinel() == node_b->is_tail_sentinel());

}

ir_function_signature *

ir_function::exact_matching_signature(const exec_list *actual_parameters)

{

   foreach_iter(exec_list_iterator, iter, signatures) {

      ir_function_signature *const sig =

	 (ir_function_signature *) iter.get();

      if (parameter_lists_match_exact(&sig->parameters, actual_parameters))

	 return sig;

   }

   return NULL;

}