PR c++/19542

        * c-common.c (c_common_nodes_and_builtins): Create global null_node.
        (warn_strict_null_sentinel): Define.
        (check_function_sentinel): Check for null_node as valid sentinel too.
        * c-common.h (c_tree_index): Added CTI_NULL.
        (null_node) Define global_tree[CTI_NULL].
        (warn_strict_null_sentinel): Declare.
        * c-opts.c: (c_common_handle_option): Handle -Wstrict-null-sentinel.
        * c.opt: (Wstrict-null-sentinel): New C++ option.
        * doc/invoke.texi (C++ Options): Document -Wstrict-null-sentinel.

        * cp-tree.h (cp_tree_index): Remove CPTI_NULL, to be defined in C
        common frontend.
        (null_node): Remove.
        * lex.c (cxx_init): Move null_node initialisation to C common frontend.

        * g++.dg/warn/sentinel.C: New testcase for __null sentinels added.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@99091 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 11 insertions, 0 deletions

diff --git a/gcc/c-common.h b/gcc/c-common.h
index 5c9330b3c90..c43531bc88a 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -159,6 +159,8 @@ enum c_tree_index
     
     CTI_VOID_ZERO,
 
+    CTI_NULL,
+
     CTI_MAX
 };
 
@@ -203,6 +205,9 @@ struct c_common_identifier GTY(())
 /* A node for `((void) 0)'.  */
 #define void_zero_node                  c_global_trees[CTI_VOID_ZERO]
 
+/* The node for C++ `__null'.  */
+#define null_node                       c_global_trees[CTI_NULL]
+
 extern GTY(()) tree c_global_trees[CTI_MAX];
 
 /* In a RECORD_TYPE, a sorted array of the fields of the type, not a
@@ -570,6 +575,12 @@ extern int flag_threadsafe_statics;
 
 extern int warn_implicit;
 
+/* Warn about using __null (as NULL in C++) as sentinel.  For code compiled
+   with GCC this doesn't matter as __null is guaranteed to have the right
+   size.  */
+
+extern int warn_strict_null_sentinel;
+
 /* Maximum template instantiation depth.  This limit is rather
    arbitrary, but it exists to limit the time it takes to notice
    infinite template instantiations.  */