re PR c++/17256 (undefined but used static or inline functions should be diagnosed)

        PR c++/17256
        * decl2.c (cp_finish_file): Fix conditions for undefined warning.
        Set TREE_NO_WARNING instead of TREE_PUBLIC.
        * pt.c (instantiate_pending_templates): Set DECL_INITIAL to avoid
        a warning on a function we didn't instantiate because of excessive
        recursion.

Co-Authored-By: James A. Morrison <phython@gcc.gnu.org>

From-SVN: r106581

gcc/cp/ChangeLog

+2005-11-06  Jason Merrill  <jason@redhat.com>
+	    James A. Morrison <phython@gcc.gnu.org>
+
+	PR c++/17256
+	* decl2.c (cp_finish_file): Fix conditions for undefined warning.
+	Set TREE_NO_WARNING instead of TREE_PUBLIC.
+	* pt.c (instantiate_pending_templates): Set DECL_INITIAL to avoid
+	a warning on a function we didn't instantiate because of excessive
+	recursion.
+
 2005-11-06  Mark Mitchell  <mark@codesourcery.com>
 
 	* class.c (record_subobject_offsets): Don't record offsets past

gcc/cp/decl2.c

@@ -3062,8 +3062,6 @@ cp_finish_file (void)
     {
       if (/* Check online inline functions that were actually used.  */
 	  TREE_USED (decl) && DECL_DECLARED_INLINE_P (decl)
-	  /* But not defined.  */
-	  && DECL_REALLY_EXTERN (decl)
 	  /* If the definition actually was available here, then the
 	     fact that the function was not defined merely represents
 	     that for some reason (use of a template repository,
@@ -3076,10 +3074,8 @@ cp_finish_file (void)
 	  && !DECL_EXPLICIT_INSTANTIATION (decl))
 	{
 	  warning (0, "inline function %q+D used but never defined", decl);
-	  /* This symbol is effectively an "extern" declaration now.
-	     This is not strictly necessary, but removes a duplicate
-	     warning.  */
-	  TREE_PUBLIC (decl) = 1;
+	  /* Avoid a duplicate warning from check_global_declaration_1.  */
+	  TREE_NO_WARNING (decl) = 1;
 	}
     }
 

gcc/cp/pt.c

@@ -11813,10 +11813,15 @@ instantiate_pending_templates (int retries)
      to avoid infinite loop.  */
   if (pending_templates && retries >= max_tinst_depth)
     {
+      tree decl = TREE_VALUE (pending_templates);
+
       error ("template instantiation depth exceeds maximum of %d"
-	    " instantiating %q+D, possibly from virtual table generation"
-	    " (use -ftemplate-depth-NN to increase the maximum)",
-	    max_tinst_depth, TREE_VALUE (pending_templates));
+	     " instantiating %q+D, possibly from virtual table generation"
+	     " (use -ftemplate-depth-NN to increase the maximum)",
+	     max_tinst_depth, decl);
+      if (TREE_CODE (decl) == FUNCTION_DECL)
+	/* Pretend that we defined it.  */
+	DECL_INITIAL (decl) = error_mark_node;
       return;
     }
 

gcc/testsuite/g++.dg/warn/undefined1.C

+// PR 17256
+
+inline static void f1(void); // { dg-warning "used but never" }
+void g1(void) { if (0) { f1(); } }
+
+inline void f2(void); // { dg-warning "used but never" }
+void g2(void) { if (0) { f2(); } }