Re: preprocessor/6386: Spurious "unterminated #if"

[Neil Booth <neil@daikokuya.demon.co.uk>]

The following reply was made to PR preprocessor/6386; it has been noted by GNATS.

From: Neil Booth <neil@daikokuya.demon.co.uk>
To: Andreas Schwab <schwab@suse.de>
Cc: gcc-gnats@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: preprocessor/6386: Spurious "unterminated #if"
Date: Sat, 20 Apr 2002 23:08:34 +0100

 Andreas Schwab wrote:-
 
 > #if 1
 > #include "b.c"
 > #endif
 > $ cat b.c
 > S
 > $ gcc -E a.c
 > # 1 "a.c"
 > # 1 "<built-in>"
 > # 1 "<command line>"
 > # 1 "a.c"
 > 
 > 
 > # 1 "b.c" 1
 > S
 > # 4 "a.c" 2
 > a.c:2:1: unterminated #if
 
 Thanks for the bug report.  I'm testing this patch for regressions;
 if it passes I'll apply it to 3.1 and 3.2.
 
 Neil.
 
 	* cppmacro.c (funlike_invocation_p): Don't step back over CPP_EOF.
 testsuite:
 	* gcc.dg/cpp/endif.h, gcc.dg/cpp/endif.c: New tests.
 
 Index: cppmacro.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/cppmacro.c,v
 retrieving revision 1.98
 diff -u -p -r1.98 cppmacro.c
 --- cppmacro.c	14 Apr 2002 18:42:46 -0000	1.98
 +++ cppmacro.c	20 Apr 2002 22:04:19 -0000
 @@ -632,12 +632,15 @@ funlike_invocation_p (pfile, node)
        return collect_args (pfile, node);
      }
  
 -  /* Back up.  We may have skipped padding, in which case backing up
 -     more than one token when expanding macros is in general too
 -     difficult.  We re-insert it in its own context.  */
 -  _cpp_backup_tokens (pfile, 1);
 -  if (padding)
 -    push_token_context (pfile, NULL, padding, 1);
 +  if (token->type != CPP_EOF)
 +    {
 +      /* Back up.  We may have skipped padding, in which case backing
 +	 up more than one token when expanding macros is in general
 +	 too difficult.  We re-insert it in its own context.  */
 +      _cpp_backup_tokens (pfile, 1);
 +      if (padding)
 +	push_token_context (pfile, NULL, padding, 1);
 +    }
  
    return NULL;
  }
 Index: testsuite/gcc.dg/cpp/endif.c
 ===================================================================
 RCS file: testsuite/gcc.dg/cpp/endif.c
 diff -N testsuite/gcc.dg/cpp/endif.c
 --- /dev/null	1 Jan 1970 00:00:00 -0000
 +++ testsuite/gcc.dg/cpp/endif.c	20 Apr 2002 22:04:19 -0000
 @@ -0,0 +1,14 @@
 +/* Copyright (C) 2002 Free Software Foundation, Inc.  */
 +
 +/* { dg-do preprocess } */
 +
 +/* Test case for PR preprocessor/6386 by Andreas Schwab.  We'd back up
 +   over the CPP_EOF token (indicating not a funlike macro invocation)
 +   in the header file, which would then be passed through as a real
 +   EOF, leading to an early exit (and therefore bogus complaint about
 +   unterminated #if).  */
 +
 +#define S(x)
 +#if 1
 +#include "endif.h"
 +#endif
 Index: testsuite/gcc.dg/cpp/endif.h
 ===================================================================
 RCS file: testsuite/gcc.dg/cpp/endif.h
 diff -N testsuite/gcc.dg/cpp/endif.h
 --- /dev/null	1 Jan 1970 00:00:00 -0000
 +++ testsuite/gcc.dg/cpp/endif.h	20 Apr 2002 22:04:19 -0000
 @@ -0,0 +1 @@
 +S