[patch,fortran] PR19261 continuation character illegal as first non-blank character in statement

[Jerry DeLisle]

PING  I will apply this weekend of no objections.

Jerry DeLisle wrote:
> :ADDPATCH fortran:
> 
> The attached patch adds warnings for illegal use of '&' in lines.  This 
> follows from F95 Standard 3.3.1.3.  With -pedantic errors are given 
> instead of warnings.
> 
> I moved the note about the unavailable error machinery to the top of 
> load_line since it applies to more than one place in this function.
> 
> If someone can figure out how to get that test case to work with the 
> deja-magic, I would appreciate it.  Can't get rid of the excess warnings 
> tests with -S
> 
> Regression tested and libgomp tested OK.  The libgomp tests require 
> Jacub's patch that fixes the PR19260 fix breakage.
> 
> OK to commit to 4.2?
> 
> Regards,
> 
> Jerry
> 
> 2006-10-06  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
> 
>     PR fortran/19261
>     * scanner.c (load_line): Add checks for illegal use of '&' and issue
>     warnings.  Issue errors with -pedantic.
> 
> 
> ------------------------------------------------------------------------
> 
> Index: scanner.c
> ===================================================================
> *** scanner.c	(revision 117424)
> --- scanner.c	(working copy)
> *************** gfc_gobble_whitespace (void)
> *** 931,937 ****
>      In fixed mode, we expand a tab that occurs within the statement
>      label region to expand to spaces that leave the next character in
>      the source region.
> !    load_line returns whether the line was truncated.  */
>   
>   static int
>   load_line (FILE * input, char **pbuf, int *pbuflen)
> --- 931,941 ----
>      In fixed mode, we expand a tab that occurs within the statement
>      label region to expand to spaces that leave the next character in
>      the source region.
> !    load_line returns whether the line was truncated.
> ! 
> !    NOTE: The error machinery isn't available at this point, so we can't
> ! 	 easily report line and column numbers consistent with other 
> ! 	 parts of gfortran.  */
>   
>   static int
>   load_line (FILE * input, char **pbuf, int *pbuflen)
> *************** load_line (FILE * input, char **pbuf, in
> *** 939,944 ****
> --- 943,949 ----
>     static int linenum = 0, current_line = 1;
>     int c, maxlen, i, preprocessor_flag, buflen = *pbuflen;
>     int trunc_flag = 0, seen_comment = 0;
> +   int seen_printable = 0, seen_ampersand = 0;
>     char *buffer;
>   
>     /* Determine the maximum allowed line length.
> *************** load_line (FILE * input, char **pbuf, in
> *** 990,996 ****
>         if (c == EOF)
>   	break;
>         if (c == '\n')
> ! 	break;
>   
>         if (c == '\r')
>   	continue;		/* Gobble characters.  */
> --- 995,1014 ----
>         if (c == EOF)
>   	break;
>         if (c == '\n')
> ! 	{
> ! 	  /* Check for illegal use of ampersand. See F95 Standard 3.3.1.3.  */
> ! 	  if (gfc_current_form == FORM_FREE 
> ! 		&& !seen_printable && seen_ampersand)
> ! 	    {
> ! 	      if (pedantic)
> ! 		gfc_error_now
> ! 		  ("'&' not allowed by itself in line %d", current_line);
> ! 	      else
> ! 		gfc_warning_now
> ! 		  ("'&' not allowed by itself in line %d", current_line);
> ! 	    }
> ! 	  break;
> ! 	}
>   
>         if (c == '\r')
>   	continue;		/* Gobble characters.  */
> *************** load_line (FILE * input, char **pbuf, in
> *** 1004,1009 ****
> --- 1022,1046 ----
>   	  break;
>   	}
>   
> +       /* Check for illegal use of ampersand. See F95 Standard 3.3.1.3.  */
> +       if (c == '&')
> + 	seen_ampersand = 1;
> + 
> +       if ((c != ' ' && c != '&' && c != '!') || (c == '!' && !seen_ampersand))
> + 	seen_printable = 1;
> +       
> +       if (gfc_current_form == FORM_FREE 
> + 	    && c == '!' && !seen_printable && seen_ampersand)
> + 	{
> + 	  if (pedantic)
> + 	    gfc_error_now (
> + 	      "'&' not allowed by itself with comment in line %d", current_line);
> + 	  else
> + 	    gfc_warning_now (
> + 	      "'&' not allowed by itself with comment in line %d", current_line);
> + 	  seen_printable = 1;
> + 	}
> + 
>         /* Is this a fixed-form comment?  */
>         if (gfc_current_form == FORM_FIXED && i == 0
>   	  && (c == '*' || c == 'c' || c == 'd'))
> *************** load_line (FILE * input, char **pbuf, in
> *** 1011,1019 ****
>   
>         if (gfc_current_form == FORM_FIXED && c == '\t' && i <= 6)
>   	{
> - 	  /* The error machinery isn't available at this point, so we can't
> - 	     easily report line and column numbers consistent with other 
> - 	     parts of gfortran.  */
>   	  if (!gfc_option.warn_tabs && seen_comment == 0
>   	      && current_line != linenum)
>   	    {
> --- 1048,1053 ----
> 
> 
> ------------------------------------------------------------------------
> 
> ! { dg-do compile }
> ! PR19261 test fix for illegal ampersands in lines.
> ! Submitted by Jerry DeLisle  <jvdelisle@gcc.gnu.org>
> print *, 12345
>    ! &  !
>    print *, 123&
>    &45  
>    print *, 54321&
>    &   ! { dg-warning "not allowed by itself with comment in line" } 
> end