[Bug c/16119] New: In C language diagnostic messages, %E should but cannot display general expressions

[Bug c/16119] New: In C language diagnostic messages, %E should but cannot display general expressions

[trt at acm dot org]

I want to add (or enhance) warnings to gcc, such as:
        warning ("operation on %qE may be undefined", written);
but the pretty-printer %E aborts on anything more complicated
than an identifier node.

I would like %E to handle general expressions.
Here is how I fixed it in gcc-3.5-20040620:

chaos$ diff -c1 c-objc-common.c.orig c-objc-common.c
*** c-objc-common.c.orig        Sun Jun 20 04:34:43 2004
--- c-objc-common.c     Mon Jun 21 13:05:45 2004
***************
*** 274,280 ****
      case 'E':
!       if (TREE_CODE (t) == IDENTIFIER_NODE)
!       n = IDENTIFIER_POINTER (t);
!       else
!         return false;
!       break;
   
--- 274,278 ----
      case 'E':
!       dump_generic_node (pp, t, 0, 0, false);
!       return true;
!

   ==================

Unfortunately that exposed glitches in the handling of `line_length'
in pretty-print.c  line_length is zero initially, incremented as characters
are accumulated, and reset to zero by pp_newline.
But pp_write_text_to_stream/pp_base_clear_output_area also resets it to zero,
which I think is a bug.  So I removed the reset in pp_base_clear_output_area,
and changed pp_base_flush to call pp_newline rather than fputc.
Here is the diff for that:

chaos$ diff -c1 pretty*.orig pretty*.c
*** pretty-print.c.orig Sat May 29 16:10:10 2004
--- pretty-print.c      Mon Jun 21 13:06:14 2004
***************
*** 367,371 ****
  {
    pp_write_text_to_stream (pp);
    pp_clear_state (pp);
-   fputc ('\n', pp->buffer->stream);
    fflush (pp->buffer->stream);
--- 367,371 ----
  {
+   pp_newline (pp);
    pp_write_text_to_stream (pp);
    pp_clear_state (pp);
    fflush (pp->buffer->stream);
***************
*** 389,391 ****
    obstack_free (&pp->buffer->obstack, obstack_base (&pp->buffer->obstack));
-   pp->buffer->line_length = 0;
  }
--- 389,390 ----

   ==================

Regardless of how this is fixed, I think it should be.
Thanks much for considering this,

Tom Truscott
trt@sas.com

-- 
           Summary: In C language diagnostic messages, %E should but cannot
                    display general expressions
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: trt at acm dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |16202
              nThis|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-25 21:01 -------
Patches goto gcc-patches@.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-26 00:09 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-06-26 00:09:13
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[jsm28 at gcc dot gnu dot org]

------- Additional Comments From jsm28 at gcc dot gnu dot org  2004-09-24 12:49 -------
%E has now been changed to handle expressions.

There is a problem with the formatting from %E, see
<http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02087.html>; the PR about
this may not yet have been opened.

I do not know whether the problem for which this PR includes a patch
still applies, and if so whether the patch is correct.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gdr at gcc dot gnu dot org,
                   |                            |jsm28 at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[trt at acm dot org]

------- Additional Comments From trt at acm dot org  2004-09-24 17:07 -------
Close but not quite right, a bogus ({anonymous}) appears.
In c-objc-common.c the suspect code is:

    case 'E':
      if (TREE_CODE (t) == IDENTIFIER_NODE)
        n = IDENTIFIER_POINTER (t);
      else
        pp_expression (cpp, t);
      break;

I think that should instead be

    case 'E':
      pp_expression (cpp, t);
      return true;


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-10-03 02:56 -------
(In reply to comment #0)
>    
> --- 274,278 ----
>       case 'E':
> !       dump_generic_node (pp, t, 0, 0, false);

I consider it a bug to attempt to use dump_generic_node() in diagnotics
(and in general).  Please consider pp_expression() or pp_declaration(),
whichever suits best.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-10-03 02:57 -------
(In reply to comment #4)
> Close but not quite right, a bogus ({anonymous}) appears.

JSM just fixed that part.
I'm closing this PR as fixed.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-10-03 02:59 -------
.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119

[Bug c/16119] In C language diagnostic messages, %E should but cannot display general expressions

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16119