cpplib.h (struct cpp_options): Add warn_cxx_operator_names field.

libcpp/:
	* include/cpplib.h (struct cpp_options): Add
	warn_cxx_operator_names field.
	(NODE_WARN_OPERATOR): Define.
	(struct cpp_hashnode): Increase flags field to 10 bits, decrease
	type to 6 bits.
	* init.c (mark_named_operators): Add flags parameter.
	(cpp_post_options): Pick flags value to pass to
	mark_named_operators.
	* lex.c (lex_identifier): If NODE_WARN_OPERATOR is set, warn that
	identifier is an operator name in C++.
gcc/:
	* fold-const.c (fold_unary): Rename local variable and to
	and_expr.
	* c-opts.c (c_common_handle_option): For -Wc++-compat set
	cpp_opts->warn_cxx_operator_names.
gcc/testsuite/:
	* gcc.dg/Wcxx-compat-13.c: New testcase.

From-SVN: r148438

4 files changed, 38 insertions, 7 deletions

diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 7023582784a..263d8441cc9 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,16 @@
+2009-06-12  Ian Lance Taylor  <iant@google.com>
+
+	* include/cpplib.h (struct cpp_options): Add
+	warn_cxx_operator_names field.
+	(NODE_WARN_OPERATOR): Define.
+	(struct cpp_hashnode): Increase flags field to 10 bits, decrease
+	type to 6 bits.
+	* init.c (mark_named_operators): Add flags parameter.
+	(cpp_post_options): Pick flags value to pass to
+	mark_named_operators.
+	* lex.c (lex_identifier): If NODE_WARN_OPERATOR is set, warn that
+	identifier is an operator name in C++.
+
 2009-06-01  Aldy Hernandez  <aldyh@redhat.com>
 
 	* include/line-map.h (LAST_SOURCE_COLUMN): New.
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index effe9a04b1f..a91f1552158 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -397,6 +397,9 @@ struct cpp_options
   /* Nonzero means handle C++ alternate operator names.  */
   unsigned char operator_names;
 
+  /* Nonzero means warn about use of C++ alternate operator names.  */
+  unsigned char warn_cxx_operator_names;
+
   /* True for traditional preprocessing.  */
   unsigned char traditional;
 
@@ -555,7 +558,8 @@ extern const char *progname;
    identifier that behaves like an operator such as "xor".
    NODE_DIAGNOSTIC is for speed in lex_token: it indicates a
    diagnostic may be required for this node.  Currently this only
-   applies to __VA_ARGS__ and poisoned identifiers.  */
+   applies to __VA_ARGS__, poisoned identifiers, and -Wc++-compat
+   warnings about NODE_OPERATOR.  */
 
 /* Hash node flags.  */
 #define NODE_OPERATOR	(1 << 0)	/* C++ named operator.  */
@@ -567,6 +571,7 @@ extern const char *progname;
 #define NODE_MACRO_ARG	(1 << 6)	/* Used during #define processing.  */
 #define NODE_USED	(1 << 7)	/* Dumped with -dU.  */
 #define NODE_CONDITIONAL (1 << 8)	/* Conditional macro */
+#define NODE_WARN_OPERATOR (1 << 9)	/* Warn about C++ named operator.  */
 
 /* Different flavors of hash node.  */
 enum node_type
@@ -636,8 +641,8 @@ struct GTY(()) cpp_hashnode {
 					   then index into directive table.
 					   Otherwise, a NODE_OPERATOR.  */
   unsigned char rid_code;		/* Rid code - for front ends.  */
-  ENUM_BITFIELD(node_type) type : 7;	/* CPP node type.  */
-  unsigned int flags : 9;		/* CPP flags.  */
+  ENUM_BITFIELD(node_type) type : 6;	/* CPP node type.  */
+  unsigned int flags : 10;		/* CPP flags.  */
 
   union _cpp_hashnode_value GTY ((desc ("CPP_HASHNODE_VALUE_IDX (%1)"))) value;
 };
diff --git a/libcpp/init.c b/libcpp/init.c
index 0f6f49f41da..e5be4e2b1b4 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -28,7 +28,7 @@ along with this program; see the file COPYING3.  If not see
 #include "localedir.h"
 
 static void init_library (void);
-static void mark_named_operators (cpp_reader *);
+static void mark_named_operators (cpp_reader *, int);
 static void read_original_filename (cpp_reader *);
 static void read_original_directory (cpp_reader *);
 static void post_options (cpp_reader *);
@@ -366,7 +366,7 @@ static const struct builtin_operator operator_array[] =
 
 /* Mark the C++ named operators in the hash table.  */
 static void
-mark_named_operators (cpp_reader *pfile)
+mark_named_operators (cpp_reader *pfile, int flags)
 {
   const struct builtin_operator *b;
 
@@ -375,7 +375,7 @@ mark_named_operators (cpp_reader *pfile)
        b++)
     {
       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
-      hp->flags |= NODE_OPERATOR;
+      hp->flags |= flags;
       hp->is_directive = 0;
       hp->directive_index = b->value;
     }
@@ -512,13 +512,20 @@ static void sanity_checks (cpp_reader *pfile)
 void
 cpp_post_options (cpp_reader *pfile)
 {
+  int flags;
+
   sanity_checks (pfile);
 
   post_options (pfile);
 
   /* Mark named operators before handling command line macros.  */
+  flags = 0;
   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
-    mark_named_operators (pfile);
+    flags |= NODE_OPERATOR;
+  if (CPP_OPTION (pfile, warn_cxx_operator_names))
+    flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
+  if (flags != 0)
+    mark_named_operators (pfile, flags);
 }
 
 /* Setup for processing input from the file named FNAME, or stdin if
diff --git a/libcpp/lex.c b/libcpp/lex.c
index ca2f2ca06f1..bab14a4baa3 100644
--- a/libcpp/lex.c
+++ b/libcpp/lex.c
@@ -560,6 +560,12 @@ lex_identifier (cpp_reader *pfile, const uchar *base, bool starts_ucn,
 	cpp_error (pfile, CPP_DL_PEDWARN,
 		   "__VA_ARGS__ can only appear in the expansion"
 		   " of a C99 variadic macro");
+
+      /* For -Wc++-compat, warn about use of C++ named operators.  */
+      if (result->flags & NODE_WARN_OPERATOR)
+	cpp_error (pfile, CPP_DL_WARNING,
+		   "identifier \"%s\" is a special operator name in C++",
+		   NODE_NAME (result));
     }
 
   return result;