+ if (to_type->base_type == GLSL_TYPE_FLOAT)
+ return PARAMETER_INT_TO_FLOAT;
+
+ /* int -> uint and any other oddball conversions */
+ return PARAMETER_OTHER_CONVERSION;
+}
+
+
+static bool
+is_better_parameter_match(parameter_match_t a_match,
+ parameter_match_t b_match)
+{
+ /* From section 6.1 of the GLSL 4.00 spec (and the ARB_gpu_shader5 spec):
+ *
+ * 1. An exact match is better than a match involving any implicit
+ * conversion.
+ *
+ * 2. A match involving an implicit conversion from float to double
+ * is better than match involving any other implicit conversion.
+ *
+ * [XXX: Not in GLSL 4.0: Only in ARB_gpu_shader5:
+ * 3. A match involving an implicit conversion from either int or uint
+ * to float is better than a match involving an implicit conversion
+ * from either int or uint to double.]
+ *
+ * If none of the rules above apply to a particular pair of conversions,
+ * neither conversion is considered better than the other.
+ *
+ * --
+ *
+ * Notably, the int->uint conversion is *not* considered to be better
+ * or worse than int/uint->float or int/uint->double.
+ */
+
+ if (a_match >= PARAMETER_INT_TO_FLOAT && b_match == PARAMETER_OTHER_CONVERSION)
+ return false;
+
+ return a_match < b_match;
+}
+
+
+static bool
+is_best_inexact_overload(const exec_list *actual_parameters,
+ ir_function_signature **matches,
+ int num_matches,
+ ir_function_signature *sig)
+{
+ /* From section 6.1 of the GLSL 4.00 spec (and the ARB_gpu_shader5 spec):
+ *
+ * "A function definition A is considered a better
+ * match than function definition B if:
+ *
+ * * for at least one function argument, the conversion for that argument
+ * in A is better than the corresponding conversion in B; and
+ *
+ * * there is no function argument for which the conversion in B is better
+ * than the corresponding conversion in A.
+ *
+ * If a single function definition is considered a better match than every
+ * other matching function definition, it will be used. Otherwise, a
+ * semantic error occurs and the shader will fail to compile."
+ */
+ for (ir_function_signature **other = matches;
+ other < matches + num_matches; other++) {
+ if (*other == sig)
+ continue;
+
+ const exec_node *node_a = sig->parameters.head;
+ const exec_node *node_b = (*other)->parameters.head;
+ const exec_node *node_p = actual_parameters->head;
+
+ bool better_for_some_parameter = false;
+
+ for (/* empty */
+ ; !node_a->is_tail_sentinel()
+ ; node_a = node_a->next,
+ node_b = node_b->next,
+ node_p = node_p->next) {
+ parameter_match_t a_match = get_parameter_match_type(
+ (const ir_variable *)node_a,
+ (const ir_rvalue *)node_p);
+ parameter_match_t b_match = get_parameter_match_type(
+ (const ir_variable *)node_b,
+ (const ir_rvalue *)node_p);
+
+ if (is_better_parameter_match(a_match, b_match))
+ better_for_some_parameter = true;
+
+ if (is_better_parameter_match(b_match, a_match))
+ return false; /* B is better for this parameter */
+ }