* include/cpplib.h (struct cpp_options): Add new boolean flag

	warn_builtin_macro_redefined.
	* init.c (cpp_create_reader): Initialize warn_builtin_macro_redefined.
	* (struct builtin_operator): Split out from previous struct builtin,
	enhance extra const correctness.
	* (struct builtin_macro): Split out from previous struct builtin, add
	new always_warn_if_redefined flag, enhance const correctness.
	* (mark_named_operators): Use struct builtin_operator.
	* (cpp_init_special_builtins): Use struct builtin_macro, add NODE_WARN
	to builtins selectively.
	* macro.c (warn_of_redefinition): Return false if a builtin macro
	is not flagged with NODE_WARN.

	* c-opts.c (c_common_handle_option): Add handling for
	-Wbuiltin-macro-redefined command line option.
	* c.opt: Added builtin-macro-redefined option.
	* doc/invoke.texi (Warning Options): Add -Wbuiltin-macro-redefined
	documentation.

	* gcc.dg/builtin-redefine.c: New.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@140461 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 0 deletions

diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index a79c26dd6b8..4f073f99433 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -349,6 +349,10 @@ struct cpp_options
      Presumably the usage is protected by the appropriate #ifdef.  */
   unsigned char warn_variadic_macros;
 
+  /* Nonzero means warn about builtin macros that are redefined or
+     explicitly undefined.  */
+  unsigned char warn_builtin_macro_redefined;
+
   /* Nonzero means turn warnings into errors.  */
   unsigned char warnings_are_errors;