Mesa (master): glsl: Implement overload resolution for ARB_gpu_shader5
Chris Forbes
chrisf at kemper.freedesktop.org
Wed Jun 4 08:19:56 UTC 2014
Module: Mesa
Branch: master
Commit: b18b4c7d74f32bfa42c5d9762d83524a51db4bd4
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=b18b4c7d74f32bfa42c5d9762d83524a51db4bd4
Author: Chris Forbes <chrisf at ijw.co.nz>
Date: Sun May 4 20:24:01 2014 +1200
glsl: Implement overload resolution for ARB_gpu_shader5
V3: Move spec citation into the code.
Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
---
src/glsl/ir_function.cpp | 71 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
diff --git a/src/glsl/ir_function.cpp b/src/glsl/ir_function.cpp
index 4411810..deec1df 100644
--- a/src/glsl/ir_function.cpp
+++ b/src/glsl/ir_function.cpp
@@ -192,6 +192,66 @@ 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)
+{
+ /* 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 */
+ }
+
+ 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,
@@ -204,6 +264,17 @@ 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 */
}
More information about the mesa-commit
mailing list