Patchwork C++ PATCH to avoid duplicate overload resolution (related to c++/48481)

commit c501c0ce3b749925475b8d3be0bc52843d37504d
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jun 30 00:03:40 2011 -0400

    	PR c++/48481
    	* name-lookup.c (struct arg_lookup): Add fn_set.
    	(add_function): Check it.
    	(lookup_arg_dependent_1): Initialize it.

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 8bf5f5f..615e177 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -33,6 +33,7 @@  along with GCC; see the file COPYING3.  If not see
 #include "debug.h"
 #include "c-family/c-pragma.h"
 #include "params.h"
+#include "pointer-set.h"
 
 /* The bindings for a particular name in a particular scope.  */
 
@@ -4864,6 +4865,7 @@  struct arg_lookup
   VEC(tree,gc) *namespaces;
   VEC(tree,gc) *classes;
   tree functions;
+  struct pointer_set_t *fn_set;
 };
 
 static bool arg_assoc (struct arg_lookup*, tree);
@@ -4883,16 +4885,11 @@  static bool arg_assoc_template_arg (struct arg_lookup*, tree);
 static bool
 add_function (struct arg_lookup *k, tree fn)
 {
-  /* We used to check here to see if the function was already in the list,
-     but that's O(n^2), which is just too expensive for function lookup.
-     Now we deal with the occasional duplicate in joust.  In doing this, we
-     assume that the number of duplicates will be small compared to the
-     total number of functions being compared, which should usually be the
-     case.  */
-
   if (!is_overloaded_fn (fn))
     /* All names except those of (possibly overloaded) functions and
        function templates are ignored.  */;
+  else if (k->fn_set && pointer_set_insert (k->fn_set, fn))
+    /* It's already in the list.  */;
   else if (!k->functions)
     k->functions = fn;
   else if (fn == k->functions)
@@ -5346,6 +5343,23 @@  lookup_arg_dependent_1 (tree name, tree fns, VEC(tree,gc) *args,
      picking up later definitions) in the second stage. */
   k.namespaces = make_tree_vector ();
 
+  /* We used to allow duplicates and let joust discard them, but
+     since the above change for DR 164 we end up with duplicates of
+     all the functions found by unqualified lookup.  So keep track
+     of which ones we've seen.  */
+  if (fns)
+    {
+      tree ovl;
+      /* We shouldn't be here if lookup found something other than
+	 namespace-scope functions.  */
+      gcc_assert (DECL_NAMESPACE_SCOPE_P (OVL_CURRENT (fns)));
+      k.fn_set = pointer_set_create ();
+      for (ovl = fns; ovl; ovl = OVL_NEXT (ovl))
+	pointer_set_insert (k.fn_set, OVL_CURRENT (ovl));
+    }
+  else
+    k.fn_set = NULL;
+
   if (include_std)
     arg_assoc_namespace (&k, std_node);
   arg_assoc_args_vec (&k, args);
@@ -5363,6 +5377,8 @@  lookup_arg_dependent_1 (tree name, tree fns, VEC(tree,gc) *args,
 
   release_tree_vector (k.classes);
   release_tree_vector (k.namespaces);
+  if (k.fn_set)
+    pointer_set_destroy (k.fn_set);
     
   return fns;
 }
diff --git a/gcc/testsuite/g++.dg/template/crash37.C b/gcc/testsuite/g++.dg/template/crash37.C
index 6072423..d5167c8 100644
--- a/gcc/testsuite/g++.dg/template/crash37.C
+++ b/gcc/testsuite/g++.dg/template/crash37.C
@@ -11,7 +11,7 @@  struct coperator_stack
 struct helper {};
 
 template<class F>
-void bla(F f) // { dg-message "bla|no known conversion" }
+void bla(F f)
 {
 }
 
@@ -20,8 +20,7 @@  struct definition
 {
  definition()
  {
-   bla(coperator_stack::push3<helper>); // { dg-error "matching" }
-   // { dg-message "candidate" "candidate note" { target *-*-* } 23 }
+   bla(coperator_stack::push3<helper>); // { dg-error "pointer to member" }
  }
 };
 
diff --git a/gcc/testsuite/g++.dg/template/ptrmem4.C b/gcc/testsuite/g++.dg/template/ptrmem4.C
index 62262c4..14f36d4 100644
--- a/gcc/testsuite/g++.dg/template/ptrmem4.C
+++ b/gcc/testsuite/g++.dg/template/ptrmem4.C
@@ -16,6 +16,5 @@  struct SpyExample
 
 void SpyExample::ready()
 {
-  queryAliases(inputs); // { dg-error "matching" }
-  // { dg-message "candidate" "candidate note" { target *-*-* } 19 }
+  queryAliases(inputs); // { dg-error "matching|unresolved" }
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.other/pmf3.C b/gcc/testsuite/g++.old-deja/g++.other/pmf3.C
index 11e648e..448d791 100644
--- a/gcc/testsuite/g++.old-deja/g++.other/pmf3.C
+++ b/gcc/testsuite/g++.old-deja/g++.other/pmf3.C
@@ -3,7 +3,7 @@ 
 // Bug: g++ was crashing after giving errors.
 
 template<class T>
-  void connect_to_method( // { dg-message "connect_to_method|no known conversion" }
+  void connect_to_method(
     T *receiver,
     void (T::*method)())
   {}
@@ -20,7 +20,6 @@  public:
 
 Gtk_Base::Gtk_Base()
 {
-  connect_to_method(this,&show);   // { dg-error "no match" } invalid pmf expression
-  // { dg-message "candidate" "candidate note" { target *-*-* } 23 }
+  connect_to_method(this,&show);   // { dg-error "pointer to member" } invalid pmf expression
   connect_to_method(this,&expose); // { dg-error "pointer to member" } invalid pmf expression
 }