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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"
/**
* \brief Check if two parameter lists match.
*
* \param list_a Parameters of the function definition.
* \param list_b Actual parameters passed to the function.
* \return If an exact match, return 0.
* If an inexact match requiring implicit conversion, return 1.
* If not a match, return -1.
* \see matching_signature()
*/
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;
/* This is set to true if there is an inexact match requiring an implicit
* conversion. */
bool inexact_match = false;
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;
if (param->type == actual->type)
continue;
/* Try to find an implicit conversion from actual to param. */
inexact_match = true;
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_const_in:
case ir_var_in:
if (!actual->type->can_implicitly_convert_to(param->type))
return -1;
break;
case ir_var_out:
if (!param->type->can_implicitly_convert_to(actual->type))
return -1;
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.
*/
return -1;
default:
assert(false);
return -1;
}
}
/* 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;
if (inexact_match)
return 1;
else
return 0;
}
ir_function_signature *
ir_function::matching_signature(const exec_list *actual_parameters)
{
ir_function_signature *match = NULL;
bool multiple_inexact_matches = false;
/* From page 42 (page 49 of the PDF) of the GLSL 1.20 spec:
*
* "If an exact match is found, the other signatures are ignored, and
* the exact match is used. Otherwise, if no exact match is found, then
* the implicit conversions in Section 4.1.10 "Implicit Conversions" will
* be applied to the calling arguments if this can make their types match
* a signature. In this case, it is a semantic error if there are
* multiple ways to apply these conversions to the actual arguments of a
* call such that the call can be made to match multiple signatures."
*/
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 we found an exact match, simply return it */
if (score == 0)
return sig;
if (score > 0) {
if (match == NULL)
match = sig;
else
multiple_inexact_matches = true;
}
}
/* There is no exact match (we would have returned it by now). If there
* are multiple inexact matches, the call is ambiguous, which is an error.
*
* FINISHME: Report a decent error. Returning NULL will likely result in
* FINISHME: a "no matching signature" error; it should report that the
* FINISHME: call is ambiguous. But reporting errors from here is hard.
*/
if (multiple_inexact_matches)
return NULL;
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;
}
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