* c-tree.h (C_DECL_USED, parser_obstack, in_alignof, in_sizeof,

	in_typeof, record_maybe_used_decl, pop_maybe_used,
	c_expr_sizeof_expr, c_expr_sizeof_type): New.
	* c-decl.c (parser_obstack): New.
	(c_init_decl_processing): Initialize parser_obstack.
	(c_write_global_declarations_1): Check for used but undefined
	static functions.
	* c-parse.in (%union): Add otype.
	(save_obstack_position): New.
	(extdefs): Use it.
	(unary_expr): Update in_sizeof and in_alignof.  Use
	c_expr_sizeof_expr and c_expr_sizeof_type.
	(sizeof): Update in_sizeof.
	(alignof): Update in_alignof.
	(typeof): Update in_typeof.
	(typespec_nonreserved_nonattr): Call pop_maybe_used.
	* c-typeck.c (in_alignof, in_sizeof, in_typeof, struct
	maybe_used_decl, maybe_used_decls, record_maybe_used_decl,
	pop_maybe_used, c_expr_sizeof_expr, c_expr_sizeof_type): New.
	(build_external_ref): Set C_DECL_USED or call
	record_maybe_used_decl if appropriate.
	* toplev.c (check_global_declarations): Check TREE_NO_WARNING.

testsuite:
	* gcc.dg/c90-static-1.c, gcc.dg/c99-static-1.c,
	gcc.dg/gnu99-static-1.c: New tests.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@87216 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 1 deletions

diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 0ffda691861..5399c175d82 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -109,6 +109,11 @@ static location_t current_function_prototype_locus;
 
 static GTY(()) tree current_function_arg_info;
 
+/* The obstack on which parser and related data structures, which are
+   not live beyond their top-level declaration or definition, are
+   allocated.  */
+struct obstack parser_obstack;
+
 /* The current statement tree.  */
 
 static GTY(()) struct stmt_tree_s c_stmt_tree;
@@ -2526,6 +2531,8 @@ c_init_decl_processing (void)
 
   current_function_decl = 0;
 
+  gcc_obstack_init (&parser_obstack);
+
   /* Make the externals scope.  */
   push_scope ();
   external_scope = current_scope;
@@ -6936,7 +6943,21 @@ c_write_global_declarations_1 (tree globals)
 
   /* Process the decls in the order they were written.  */
   for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
-    vec[i] = decl;
+    {
+      vec[i] = decl;
+      /* Check for used but undefined static functions using the C
+	 standard's definition of "used", and set TREE_NO_WARNING so
+	 that check_global_declarations doesn't repeat the check.  */
+      if (TREE_CODE (decl) == FUNCTION_DECL
+	  && DECL_INITIAL (decl) == 0
+	  && DECL_EXTERNAL (decl)
+	  && !TREE_PUBLIC (decl)
+	  && C_DECL_USED (decl))
+	{
+	  pedwarn ("%J%<%F%> used but never defined", decl, decl);
+	  TREE_NO_WARNING (decl) = 1;
+	}
+    }
 
   wrapup_global_declarations (vec, len);
   check_global_declarations (vec, len);