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 <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 5878c051b152a6857c65cf879c4d640cdb6e2dc2..1faae3c7259420cd434606e96f432532959820ae 100644 (file)
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -564,6 +564,13 @@ public:
       return signatures.iterator();
    }
 
+   /**
+    * 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.

diff --git a/src/glsl/ir_function.cpp b/src/glsl/ir_function.cpp
index 51d32b46f98425a46326117a64452527b38abddd..b34a50081682e795bc9f537d2d6a89087ac77d3f 100644 (file)
--- a/src/glsl/ir_function.cpp
+++ b/src/glsl/ir_function.cpp
@@ -117,6 +117,14 @@ parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
 
 ir_function_signature *
 ir_function::matching_signature(const exec_list *actual_parameters)
+{
+   bool is_exact;
+   return matching_signature(actual_parameters, &is_exact);
+}
+
+ir_function_signature *
+ir_function::matching_signature(const exec_list *actual_parameters,
+                               bool *is_exact)
 {
    ir_function_signature *match = NULL;
    bool multiple_inexact_matches = false;
@@ -137,6 +145,7 @@ ir_function::matching_signature(const exec_list *actual_parameters)
 
       switch (parameter_lists_match(& sig->parameters, actual_parameters)) {
       case PARAMETER_LIST_EXACT_MATCH:
+        *is_exact = true;
         return sig;
       case PARAMETER_LIST_INEXACT_MATCH:
         if (match == NULL)
@@ -159,6 +168,8 @@ ir_function::matching_signature(const exec_list *actual_parameters)
     * FINISHME: a "no matching signature" error; it should report that the
     * FINISHME: call is ambiguous.  But reporting errors from here is hard.
     */
+   *is_exact = false;
+
    if (multiple_inexact_matches)
       return NULL;