Re: [RFA] Fix mi-break.exp: 'b "basics.c":16'

[Daniel Jacobowitz <drow@mvista.com>]

On Thu, May 09, 2002 at 03:40:42PM -0700, Michael Snyder wrote:
> Daniel Jacobowitz wrote:
> > 
> > [I dislike decode_line_1.  But that seems to be the general consensus...]
> > 
> > There was a logic error in the code to handle "file":line.  Several,
> > actually.  I suspect that it once worked and had bitrotten as the behavior
> > of the function changed.  For instance, at the beginning of the function:
> > 
> >   if (p[0] == '"')
> >     {
> >       is_quote_enclosed = 1;
> >       (*argptr)++;
> >       p++;
> >     }
> > 
> > Then below it checked 'is_quote_enclosed && (**argptr) == '"'). 
> 
> [line break inserted]
> 
> > That'll only be true given a literal '"":<line>', which was not 
> > the intent of the test.
> 
> I don't understand this statement.  Between the two bits of text
> you've named, both p and *argptr are changed.  Seems to me, there 
> could be any number of characters between the two quotes.

This is the part that took me the longest to work out in the first
place, I think.  `p' being changed doesn't matter here; it should end
up point at (before?) the colon.

The first if statement is at line 630.  The second is at 929.  Between
the two, *argptr is only changed if we found a C++ class.  It might be
changed on "interestingly" named files, also, but if so it's purely a
bug in the twistiness of linespec.  At line 633 it points to the
_second_ character (right after the first quote), so if **argptr ==
'"', that means the second quote is right after the first.

> 
> 
> > This patch updates the behavior, should change nothing else, and causes no
> > regressions.  OK to check in?
> > 
> > --
> > Daniel Jacobowitz                           Carnegie Mellon University
> > MontaVista Software                         Debian GNU/Linux Developer
> > 
> > 2002-04-02  Daniel Jacobowitz  <drow@mvista.com>
> > 
> >         * linespec.c (decode_line_1): Check for a double quote after
> >         a filename correctly.
> > 
> > Index: linespec.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/linespec.c,v
> > retrieving revision 1.17
> > diff -u -p -r1.17 linespec.c
> > --- linespec.c  2002/03/22 18:57:07     1.17
> > +++ linespec.c  2002/04/03 00:19:30
> > @@ -929,20 +929,12 @@ decode_line_1 (char **argptr, int funfir
> >        if ((*p == '"') && is_quote_enclosed)
> >         --p;
> >        copy = (char *) alloca (p - *argptr + 1);
> > -      if ((**argptr == '"') && is_quote_enclosed)
> > -       {
> > -         memcpy (copy, *argptr + 1, p - *argptr - 1);
> > -         /* It may have the ending quote right after the file name */
> > -         if (copy[p - *argptr - 2] == '"')
> > -           copy[p - *argptr - 2] = 0;
> > -         else
> > -           copy[p - *argptr - 1] = 0;
> > -       }
> > +      memcpy (copy, *argptr, p - *argptr);
> > +      /* It may have the ending quote right after the file name */
> > +      if (is_quote_enclosed && copy[p - *argptr - 1] == '"')
> > +       copy[p - *argptr - 1] = 0;
> >        else
> > -       {
> > -         memcpy (copy, *argptr, p - *argptr);
> > -         copy[p - *argptr] = 0;
> > -       }
> > +       copy[p - *argptr] = 0;
> > 
> >        /* Find that file's data.  */
> >        s = lookup_symtab (copy);
> 

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer