Re: [RFA] import drow dbxread.c fix to branch

[Elena Zannoni <ezannoni at redhat dot com>]

Daniel Jacobowitz writes:
 > > 
 > > Take a look at the way gdbtk does it, in
 > > gdbtk/generic/gdbtk-cmd.c:gdb_disassemble_driver().
 > > Can we adopt that solution?
 > > 
 > > (I really can't wait until we can get rid of this duplication/triplication of
 > > disassembly code. I think I'll start cleaning some things up).
 > 
 > I'm not sure.  That code assumes a different meaning of line==0 than
 > the one we're using.  Particularly, if I understand correctly, the
 > meaning in gdbtk comes from a set of Cygnus-internal stabs for handling
 > live range splitting, which never made it into any public GCC and are
 > completely obsoleted by DWARF-2.  I prefer:
 > 

Yes, you are right, that code predates even gdbtk bein contributed
publically. I initially thought that it was a recent fix.


 >  > +      /* Skip any end-of-function markers.  */
 >  > +      if (le[i].line == 0)
 >  > +        continue;
 >  > +
 > 
 > 
 > to:
 > 
 >           /* GCC sometimes emits line directives with a linenumber
 >              of 0.  It does this to handle live range splitting.
 >              This may be a bug, but we need to be able to handle it.
 >              For now, use the previous instructions line number.
 >              Since this is a bit of a hack anyway, we will just lose
 >              if the bogus sline is the first line of the range.  For
 >              functions, I have never seen this to be the case.  */
 >           
 >           if (le[i].line != 0)
 >             {
 >               mle[newlines].line = le[i].line;
 >             }
 >           else
 >             {
 >               if (newlines > 0)
 >                 mle[newlines].line = mle[newlines - 1].line;
 >             }
 > 
 > 
 > i.e. skip the line, not fake up a line number for it.  It's a
 > special-purpose marker, not a generic line number.
 > 
 > If you agree with me, want me to update gdbtk's version to match?  Does
 > this same code exist in a third location?
 > 

I guess posting a patch to the insight list can do no harm. It's up to
them to approve it.

There is no real third location, but rather a third way to do
disassembly in gdb proper (disassemble_cmd).

Anyway, the code can go in for the MI part.

Elena


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