except.c (pending_noexcept, [...]): New.

* except.c (pending_noexcept, pending_noexcept_checks): New.
	(perform_deferred_noexcept_checks): New.
	(maybe_noexcept_warning): Split from...
	(finish_noexcept_expr): ...here.  Adjust.
	* decl2.c (cp_write_global_declarations): Call
	perform_deferred_noexcept_checks.
	* cp-tree.h: And declare it.

From-SVN: r163379

gcc/cp/ChangeLog

@@ -1,3 +1,13 @@
+2010-08-19  Jason Merrill  <jason@redhat.com>
+
+	* except.c (pending_noexcept, pending_noexcept_checks): New.
+	(perform_deferred_noexcept_checks): New.
+	(maybe_noexcept_warning): Split from...
+	(finish_noexcept_expr): ...here.  Adjust.
+	* decl2.c (cp_write_global_declarations): Call
+	perform_deferred_noexcept_checks.
+	* cp-tree.h: And declare it.
+
 2010-08-18  Nathan Froyd  <froydnj@codesourcery.com>
 
 	PR c++/45049

gcc/cp/cp-tree.h

@@ -4883,6 +4883,7 @@ extern tree build_throw				(tree);
 extern int nothrow_libfn_p			(const_tree);
 extern void check_handlers			(tree);
 extern tree finish_noexcept_expr		(tree, tsubst_flags_t);
+extern void perform_deferred_noexcept_checks	(void);
 extern bool nothrow_spec_p			(const_tree);
 extern bool type_noexcept_p			(const_tree);
 extern bool type_throw_all_p			(const_tree);

gcc/cp/decl2.c

@@ -3934,6 +3934,8 @@ cp_write_global_declarations (void)
 				      VEC_length (tree, pending_statics));
     }
 
+  perform_deferred_noexcept_checks ();
+
   /* Generate hidden aliases for Java.  */
   if (candidates)
     {

gcc/cp/except.c

@@ -1069,6 +1069,51 @@ check_noexcept_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
   return NULL_TREE;
 }
 
+/* If a function that causes a noexcept-expression to be false isn't
+   defined yet, remember it and check it for TREE_NOTHROW again at EOF.  */
+
+typedef struct GTY(()) pending_noexcept {
+  tree fn;
+  location_t loc;
+} pending_noexcept;
+DEF_VEC_O(pending_noexcept);
+DEF_VEC_ALLOC_O(pending_noexcept,gc);
+static GTY(()) VEC(pending_noexcept,gc) *pending_noexcept_checks;
+
+/* FN is a FUNCTION_DECL that caused a noexcept-expr to be false.  Warn if
+   it can't throw.  */
+
+static void
+maybe_noexcept_warning (tree fn)
+{
+  if (TREE_NOTHROW (fn))
+    {
+      warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> "
+	       "because of a call to %qD", fn);
+      warning (OPT_Wnoexcept, "but %q+D does not throw; perhaps "
+	       "it should be declared %<noexcept%>", fn);
+    }
+}
+
+/* Check any functions that weren't defined earlier when they caused a
+   noexcept expression to evaluate to false.  */
+
+void
+perform_deferred_noexcept_checks (void)
+{
+  int i;
+  pending_noexcept *p;
+  location_t saved_loc = input_location;
+  for (i = 0;
+       VEC_iterate (pending_noexcept, pending_noexcept_checks, i, p);
+       ++i)
+    {
+      input_location = p->loc;
+      maybe_noexcept_warning (p->fn);
+    }
+  input_location = saved_loc;
+}
+
 /* Evaluate noexcept ( EXPR ).  */
 
 tree
@@ -1082,13 +1127,20 @@ finish_noexcept_expr (tree expr, tsubst_flags_t complain)
   fn = cp_walk_tree_without_duplicates (&expr, check_noexcept_r, 0);
   if (fn)
     {
-      if ((complain & tf_warning) && TREE_CODE (fn) == FUNCTION_DECL
-	  && TREE_NOTHROW (fn) && !DECL_ARTIFICIAL (fn))
+      if ((complain & tf_warning) && warn_noexcept
+	  && TREE_CODE (fn) == FUNCTION_DECL)
 	{
-	  warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> "
-		   "because of a call to %qD", fn);
-	  warning (OPT_Wnoexcept, "but %q+D does not throw; perhaps "
-		   "it should be declared %<noexcept%>", fn);
+	  if (!DECL_INITIAL (fn))
+	    {
+	      /* Not defined yet; check again at EOF.  */
+	      pending_noexcept *p
+		= VEC_safe_push (pending_noexcept, gc,
+				 pending_noexcept_checks, NULL);
+	      p->fn = fn;
+	      p->loc = input_location;
+	    }
+	  else
+	    maybe_noexcept_warning (fn);
 	}
       return boolean_false_node;
     }

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2010-08-19  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/cpp0x/noexcept09.C: New.
+
 2010-08-19  Daniel Kraft  <d@domob.eu>
 
 	PR fortran/29785

gcc/testsuite/g++.dg/cpp0x/noexcept09.C

@@ -0,0 +1,14 @@
+// Test that -Wnoexcept works with templates
+// { dg-options "-std=c++0x -Wnoexcept" }
+
+template <class T>
+T f (T t) { return t; }		// { dg-warning "does not throw" }
+
+#define SA(X) static_assert(X, #X)
+
+SA (!noexcept(f(1)));		// { dg-warning "noexcept" }
+
+int main()
+{
+  f(1);				// Use f(int) so it gets instantiated
+}