glsl: Add a new matching_signature() variant that returns exact/inexact.

When matching function signatures across multiple linked shaders, we
often want to see if the current shader has _any_ match, but also know
whether or not it was exact.  (If not, we may want to keep looking.)

This could be done via the existing mechanisms:

   sig = f->exact_matching_signature(params);
   if (sig != NULL) {
      exact = true;
   } else {
      sig = f->matching_signature(params);
      exact = false;
   }

However, this requires walking the list of function signatures twice,
which also means walking each signature's formal parameter lists twice.
This could be rather expensive.

Since matching_signature already internally knows whether a match was
exact or not, we can just return it to get that information for free.

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 5878c051b15..1faae3c7259 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -566,6 +566,13 @@ public:
 
    /**
     * Find a signature that matches a set of actual parameters, taking implicit
+    * conversions into account.  Also flags whether the match was exact.
+    */
+   ir_function_signature *matching_signature(const exec_list *actual_param,
+					     bool *match_is_exact);
+
+   /**
+    * Find a signature that matches a set of actual parameters, taking implicit
     * conversions into account.
     */
    ir_function_signature *matching_signature(const exec_list *actual_param);