Patch: PR preprocessor/28227

[Tom Tromey <tromey at redhat dot com>]

This patch fixes PR preprocessor/28227.

Both '#ifdef defined' and '#ifndef defined' are valid according to the
C standard.  This patch adds an argument to lex_macro_node to disable
the check for 'defined' in these cases.

While writing this I noticed that we silently accept '#if defined defined',
which according to the standard is undefined.  I wasn't sure what, if
anything, to do about this, so I left it as-is.

Bootstrapped & tested on x86 FC6.  New test case included.

Ok?

Tom

:ADDPATCH preprocesssor:

libcpp
2006-12-29  Tom Tromey  <tromey@redhat.com>

	PR preprocessor/28227:
	* directives.c (lex_macro_node): Added 'def_or_undef' argument.
	(do_define): Update.
	(do_undef): Update.
	(do_ifdef): Update.
	(do_ifndef): Update.

gcc/testsuite
2006-12-29  Tom Tromey  <tromey@redhat.com>

	PR preprocessor/28227:
	* gcc.dg/cpp/pr28227.c: New file.

Index: libcpp/directives.c
===================================================================
--- libcpp/directives.c	(revision 120244)
+++ libcpp/directives.c	(working copy)
@@ -1,6 +1,7 @@
 /* CPP Library. (Directive handling.)
    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005,
+   2006 Free Software Foundation, Inc.
    Contributed by Per Bothner, 1994-95.
    Based on CCCP program by Paul Rubin, June 1986
    Adapted to ANSI C, Richard Stallman, Jan 1987
@@ -102,7 +103,7 @@
 static unsigned int read_flag (cpp_reader *, unsigned int);
 static int strtoul_for_line (const uchar *, unsigned int, unsigned long *);
 static void do_diagnostic (cpp_reader *, int, int);
-static cpp_hashnode *lex_macro_node (cpp_reader *);
+static cpp_hashnode *lex_macro_node (cpp_reader *, bool);
 static int undefine_macros (cpp_reader *, cpp_hashnode *, void *);
 static void do_include_common (cpp_reader *, enum include_type);
 static struct pragma_entry *lookup_pragma_entry (struct pragma_entry *,
@@ -504,7 +512,7 @@
 /* Checks for validity the macro name in #define, #undef, #ifdef and
    #ifndef directives.  */
 static cpp_hashnode *
-lex_macro_node (cpp_reader *pfile)
+lex_macro_node (cpp_reader *pfile, bool def_or_undef)
 {
   const cpp_token *token = _cpp_lex_token (pfile);
 
@@ -519,7 +527,7 @@
     {
       cpp_hashnode *node = token->val.node;
 
-      if (node == pfile->spec_nodes.n_defined)
+      if (def_or_undef && node == pfile->spec_nodes.n_defined)
 	cpp_error (pfile, CPP_DL_ERROR,
 		   "\"defined\" cannot be used as a macro name");
       else if (! (node->flags & NODE_POISONED))
@@ -542,7 +550,7 @@
 static void
 do_define (cpp_reader *pfile)
 {
-  cpp_hashnode *node = lex_macro_node (pfile);
+  cpp_hashnode *node = lex_macro_node (pfile, true);
 
   if (node)
     {
@@ -561,7 +569,7 @@
 static void
 do_undef (cpp_reader *pfile)
 {
-  cpp_hashnode *node = lex_macro_node (pfile);
+  cpp_hashnode *node = lex_macro_node (pfile, true);
 
   if (node)
     {
@@ -1607,7 +1613,7 @@
 
   if (! pfile->state.skipping)
     {
-      const cpp_hashnode *node = lex_macro_node (pfile);
+      const cpp_hashnode *node = lex_macro_node (pfile, false);
 
       if (node)
 	{
@@ -1629,7 +1635,7 @@
 
   if (! pfile->state.skipping)
     {
-      node = lex_macro_node (pfile);
+      node = lex_macro_node (pfile, false);
 
       if (node)
 	{


Index: gcc/testsuite/gcc.dg/cpp/pr28227.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/pr28227.c	(revision 0)
+++ gcc/testsuite/gcc.dg/cpp/pr28227.c	(revision 0)
@@ -0,0 +1,10 @@
+/* Copyright (C) 2006 Free Software Foundation, Inc.  */
+/* PR preprocessor/28227 */
+
+/* { dg-do preprocess } */
+#ifdef defined
+#endif
+#ifndef defined
+#endif
+
+int x;