re PR c++/561 (std:unclear about Overloaded Function Pointer resolution)

	PR c++/561
	* decl.c (static_fn_type): Split out...
	(revert_static_member_fn): ...from here.
	* cp-tree.h: Declare it.
	* class.c (resolve_address_of_overloaded_function): Use it to compare
	pointers to member functions.
	* typeck.c (build_static_cast_1): Call instantiate_type.

From-SVN: r154336

5 files changed, 63 insertions, 38 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4e1f469..6a30b67 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2009-11-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/561
+	* decl.c (static_fn_type): Split out...
+	(revert_static_member_fn): ...from here.
+	* cp-tree.h: Declare it.
+	* class.c (resolve_address_of_overloaded_function): Use it to compare
+	pointers to member functions.
+	* typeck.c (build_static_cast_1): Call instantiate_type.
+
 2009-11-18  Shujing Zhao  <pearly.zhao@oracle.com>
 
 	PR c++/40892
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index c798ba2..3cf15fb 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6065,6 +6065,7 @@ resolve_address_of_overloaded_function (tree target_type,
      interoperability with most_specialized_instantiation.  */
   tree matches = NULL_TREE;
   tree fn;
+  tree target_fn_type;
 
   /* By the time we get here, we should be seeing only real
      pointer-to-member types, not the internal POINTER_TYPE to
@@ -6096,6 +6097,15 @@ resolve_address_of_overloaded_function (tree target_type,
       return error_mark_node;
     }
 
+  /* Non-member functions and static member functions match targets of type
+     "pointer-to-function" or "reference-to-function."  Nonstatic member
+     functions match targets of type "pointer-to-member-function;" the
+     function type of the pointer to member is used to select the member
+     function from the set of overloaded member functions.
+
+     So figure out the FUNCTION_TYPE that we want to match against.  */
+  target_fn_type = static_fn_type (target_type);
+
   /* If we can find a non-template function that matches, we can just
      use it.  There's no point in generating template instantiations
      if we're just going to throw them out anyhow.  But, of course, we
@@ -6107,7 +6117,6 @@ resolve_address_of_overloaded_function (tree target_type,
       for (fns = overload; fns; fns = OVL_NEXT (fns))
 	{
 	  tree fn = OVL_CURRENT (fns);
-	  tree fntype;
 
 	  if (TREE_CODE (fn) == TEMPLATE_DECL)
 	    /* We're not looking for templates just yet.  */
@@ -6125,13 +6134,7 @@ resolve_address_of_overloaded_function (tree target_type,
 	    continue;
 
 	  /* See if there's a match.  */
-	  fntype = TREE_TYPE (fn);
-	  if (is_ptrmem)
-	    fntype = build_ptrmemfunc_type (build_pointer_type (fntype));
-	  else if (!is_reference)
-	    fntype = build_pointer_type (fntype);
-
-	  if (can_convert_arg (target_type, fntype, fn, LOOKUP_NORMAL))
+	  if (same_type_p (target_fn_type, static_fn_type (fn)))
 	    matches = tree_cons (fn, NULL_TREE, matches);
 	}
     }
@@ -6141,7 +6144,6 @@ resolve_address_of_overloaded_function (tree target_type,
      match we need to look at them, too.  */
   if (!matches)
     {
-      tree target_fn_type;
       tree target_arg_types;
       tree target_ret_type;
       tree fns;
@@ -6149,18 +6151,9 @@ resolve_address_of_overloaded_function (tree target_type,
       unsigned int nargs, ia;
       tree arg;
 
-      if (is_ptrmem)
-	target_fn_type
-	  = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (target_type));
-      else
-	target_fn_type = TREE_TYPE (target_type);
       target_arg_types = TYPE_ARG_TYPES (target_fn_type);
       target_ret_type = TREE_TYPE (target_fn_type);
 
-      /* Never do unification on the 'this' parameter.  */
-      if (TREE_CODE (target_fn_type) == METHOD_TYPE)
-	target_arg_types = TREE_CHAIN (target_arg_types);
-
       nargs = list_length (target_arg_types);
       args = XALLOCAVEC (tree, nargs);
       for (arg = target_arg_types, ia = 0;
@@ -6173,7 +6166,6 @@ resolve_address_of_overloaded_function (tree target_type,
 	{
 	  tree fn = OVL_CURRENT (fns);
 	  tree instantiation;
-	  tree instantiation_type;
 	  tree targs;
 
 	  if (TREE_CODE (fn) != TEMPLATE_DECL)
@@ -6201,14 +6193,7 @@ resolve_address_of_overloaded_function (tree target_type,
 	    continue;
 
 	  /* See if there's a match.  */
-	  instantiation_type = TREE_TYPE (instantiation);
-	  if (is_ptrmem)
-	    instantiation_type =
-	      build_ptrmemfunc_type (build_pointer_type (instantiation_type));
-	  else if (!is_reference)
-	    instantiation_type = build_pointer_type (instantiation_type);
-	  if (can_convert_arg (target_type, instantiation_type, instantiation,
-			       LOOKUP_NORMAL))
+	  if (same_type_p (target_fn_type, static_fn_type (instantiation)))
 	    matches = tree_cons (instantiation, fn, matches);
 	}
 
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 3aff7ec..cae259b 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -4610,6 +4610,7 @@ extern void maybe_register_incomplete_var	(tree);
 extern void maybe_commonize_var			(tree);
 extern void complete_vars			(tree);
 extern void finish_stmt				(void);
+extern tree static_fn_type			(tree);
 extern void revert_static_member_fn		(tree);
 extern void fixup_anonymous_aggr		(tree);
 extern int check_static_variable_definition	(tree, tree);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 599b39a..29e32c8 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -12812,26 +12812,47 @@ finish_stmt (void)
 {
 }
 
+/* Return the FUNCTION_TYPE that corresponds to MEMFNTYPE, which can be a
+   FUNCTION_DECL, METHOD_TYPE, FUNCTION_TYPE, pointer or reference to
+   METHOD_TYPE or FUNCTION_TYPE, or pointer to member function.  */
+
+tree
+static_fn_type (tree memfntype)
+{
+  tree fntype;
+  tree args;
+  int quals;
+
+  if (TYPE_PTRMEMFUNC_P (memfntype))
+    memfntype = TYPE_PTRMEMFUNC_FN_TYPE (memfntype);
+  if (POINTER_TYPE_P (memfntype)
+      || TREE_CODE (memfntype) == FUNCTION_DECL)
+    memfntype = TREE_TYPE (memfntype);
+  if (TREE_CODE (memfntype) == FUNCTION_TYPE)
+    return memfntype;
+  gcc_assert (TREE_CODE (memfntype) == METHOD_TYPE);
+  args = TYPE_ARG_TYPES (memfntype);
+  fntype = build_function_type (TREE_TYPE (memfntype), TREE_CHAIN (args));
+  quals = cp_type_quals (TREE_TYPE (TREE_VALUE (args)));
+  fntype = build_qualified_type (fntype, quals);
+  fntype = (cp_build_type_attribute_variant
+	    (fntype, TYPE_ATTRIBUTES (memfntype)));
+  fntype = (build_exception_variant
+	    (fntype, TYPE_RAISES_EXCEPTIONS (memfntype)));
+  return fntype;
+}
+
 /* DECL was originally constructed as a non-static member function,
    but turned out to be static.  Update it accordingly.  */
 
 void
 revert_static_member_fn (tree decl)
 {
-  tree tmp;
-  tree function = TREE_TYPE (decl);
-  tree args = TYPE_ARG_TYPES (function);
+  TREE_TYPE (decl) = static_fn_type (decl);
 
-  if (cp_type_quals (TREE_TYPE (TREE_VALUE (args)))
-      != TYPE_UNQUALIFIED)
+  if (cp_type_quals (TREE_TYPE (decl)) != TYPE_UNQUALIFIED)
     error ("static member function %q#D declared with type qualifiers", decl);
 
-  args = TREE_CHAIN (args);
-  tmp = build_function_type (TREE_TYPE (function), args);
-  tmp = build_qualified_type (tmp, cp_type_quals (function));
-  tmp = build_exception_variant (tmp,
-				 TYPE_RAISES_EXCEPTIONS (function));
-  TREE_TYPE (decl) = tmp;
   if (DECL_ARGUMENTS (decl))
     DECL_ARGUMENTS (decl) = TREE_CHAIN (DECL_ARGUMENTS (decl));
   DECL_STATIC_FUNCTION_P (decl) = 1;
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 3a95259..4c02f78 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -5346,6 +5346,14 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
 
   orig = expr;
 
+  /* Resolve overloaded address here rather than once in
+     implicit_conversion and again in the inverse code below.  */
+  if (TYPE_PTRMEMFUNC_P (type) && type_unknown_p (expr))
+    {
+      expr = instantiate_type (type, expr, complain);
+      intype = TREE_TYPE (expr);
+    }
+
   /* [expr.static.cast]
 
      An expression e can be explicitly converted to a type T using a