The ARB_gpu_shader5 spec says:
"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."
Signed-off-by: Chris Forbes <chr...@ijw.co.nz>
---
src/glsl/ir_function.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/src/glsl/ir_function.cpp b/src/glsl/ir_function.cpp
index 6d2de47..7bd3399 100644
--- a/src/glsl/ir_function.cpp
+++ b/src/glsl/ir_function.cpp
@@ -184,6 +184,51 @@ is_better_parameter_match(parameter_match_t a_match,
}
+static bool
+is_best_inexact_overload(const exec_list *actual_parameters,
+ ir_function_signature **matches,
+ int num_matches,
+ ir_function_signature *sig)
+{
+ 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 */
+ }
+
+ if (!better_for_some_parameter)
+ return false; /* A must be better than B for some parameter */
+
+ }
+
+ return true;
+}
+
+
static ir_function_signature *
choose_best_inexact_overload(_mesa_glsl_parse_state *state,
const exec_list *actual_parameters,
@@ -196,6 +241,17 @@ choose_best_inexact_overload(_mesa_glsl_parse_state *state,
if (num_matches == 1)
return *matches;
+ /* Without GLSL 4.0 / ARB_gpu_shader5, there is no overload resolution
+ * among multiple inexact matches. Note that state may be NULL here if
+ * called from the linker; in that case we assume everything supported in
+ * any GLSL version is available. */
+ if (!state || state->is_version(400, 0) || state->ARB_gpu_shader5_enable) {
+ for (ir_function_signature **sig = matches; sig < matches + num_matches;
sig++) {
+ if (is_best_inexact_overload(actual_parameters, matches, num_matches,
*sig))
+ return *sig;
+ }
+ }
+
return NULL; /* no best candidate */
}
--
1.9.2
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