[RFC][Fortran,patch] %C error diagnostic location

[Tobias Burnus <burnus at net-b dot de>]

Hi all,

my feeling is that %C locations are always off by one, e.g., showing the 
(1) under the last white-space character before the place where the 
error occurred – the match starts at the character after the 
gfc_current_location.

That bothered my for a while – but today, I was wondering whether one 
shouldn't simply bump the %C location by one – such that it shows at the 
first wrong character and not at the last okay character.

What do you think?


Another observation (unfixed): If gfortran buffers the error, the %C 
does not seem to get resolved at gfc_{error,warning} time but at the 
time when the buffer is flushed – which will have a reset error location.

Cheers,

Tobias

	* error (error_print, gfc_format_decoder): Fix off-by one issue with %C.

diff --git a/gcc/fortran/error.c b/gcc/fortran/error.c
index a0ce7a6b190..815cae9d7e7 100644
--- a/gcc/fortran/error.c
+++ b/gcc/fortran/error.c
@@ -618,12 +618,18 @@ error_print (const char *type, const char *format0, va_list argp)
 	      {
 		l2 = loc;
 		arg[pos].u.stringval = "(2)";
+		/* Point %C first offending character not the last good one. */
+		if (arg[pos].type == TYPE_CURRENTLOC)
+		  l2->nextc++;
 	      }
 	    else
 	      {
 		l1 = loc;
 		have_l1 = 1;
 		arg[pos].u.stringval = "(1)";
+		/* Point %C first offending character not the last good one. */
+		if (arg[pos].type == TYPE_CURRENTLOC)
+		  l1->nextc++;
 	      }
 	    break;
 
@@ -963,6 +969,9 @@ gfc_format_decoder (pretty_printer *pp, text_info *text, const char *spec,
 	  loc = va_arg (*text->args_ptr, locus *);
 	gcc_assert (loc->nextc - loc->lb->line >= 0);
 	unsigned int offset = loc->nextc - loc->lb->line;
+	if (*spec == 'C')
+	  /* Point %C first offending character not the last good one. */
+	  offset++;
 	/* If location[0] != UNKNOWN_LOCATION means that we already
 	   processed one of %C/%L.  */
 	int loc_num = text->get_location (0) == UNKNOWN_LOCATION ? 0 : 1;
@@ -1400,7 +1409,7 @@ gfc_internal_error (const char *gmsgid, ...)
 void
 gfc_clear_error (void)
 {
-  error_buffer.flag = 0;
+  error_buffer.flag = false;
   warnings_not_errors = false;
   gfc_clear_pp_buffer (pp_error_buffer);
 }