Re: [RFA/stabs] Fix gdb/280 infinite loop in userdef.exp

[Daniel Jacobowitz <drow@mvista.com>]

Committed with comment.  Sometime down the road I hope to try to clean
that up - I'll have some other patches affecting stubbed types, which
are related to this same hack.

On Sun, Feb 03, 2002 at 05:25:30PM -0500, Jim Blandy wrote:
> 
> Approved.  Could you also put a comment in the stabs reader saying
> that this isn't really a kosher way to construct types?
> 
> Daniel Jacobowitz <drow@mvista.com> writes:
> 
> > Another problem exposed by the way the stabs reader handles types.  It does
> > '*type = *xtype' at one point, which dies horribly for qualified types (and
> > messes up pointer types, too...).  I don't immediately see a way to get rid
> > of that line, so I made an interface to do the copy correctly.
> > 
> > For reference, that appears to be the only place in GDB this is actually
> > done.  Other readers must handle forward-referenced types somehow...
> > 
> > Without this patch we enter an infinite loop because the cv-chain is
> > corrupted.
> > 
> > OK to commit?
> > 
> > -- 
> > Daniel Jacobowitz                           Carnegie Mellon University
> > MontaVista Software                         Debian GNU/Linux Developer
> > 
> > 2002-02-01  Daniel Jacobowitz  <drow@mvista.com>
> > 
> > 	PR gdb/280
> > 	* gdbtypes.c (replace_type): New function.
> > 	* gdbtypes.h (replace_type): Add prototype.
> > 	* stabsread.c (read_type): Use replace_type.
> > 
> > Index: gdbtypes.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/gdbtypes.c,v
> > retrieving revision 1.38
> > diff -u -p -r1.38 gdbtypes.c
> > --- gdbtypes.c	2002/01/22 19:57:40	1.38
> > +++ gdbtypes.c	2002/02/01 23:48:45
> > @@ -519,6 +519,32 @@ finish_cv_type (struct type *type)
> >      }
> >  }
> >  
> > +/* Replace the contents of ntype with the type *type.
> > +
> > +   This function should not be necessary, but is due to quirks in the stabs
> > +   reader.  This should go away.  It does not handle the replacement type
> > +   being cv-qualified; it could be easily fixed to, but it should go away,
> > +   remember?  */
> > +void
> > +replace_type (struct type *ntype, struct type *type)
> > +{
> > +  struct type *cv_chain, *as_chain, *ptr, *ref;
> > +
> > +  cv_chain = TYPE_CV_TYPE (ntype);
> > +  as_chain = TYPE_AS_TYPE (ntype);
> > +  ptr = TYPE_POINTER_TYPE (ntype);
> > +  ref = TYPE_REFERENCE_TYPE (ntype);
> > +
> > +  *ntype = *type;
> > +
> > +  TYPE_POINTER_TYPE (ntype) = ptr;
> > +  TYPE_REFERENCE_TYPE (ntype) = ref;
> > +  TYPE_CV_TYPE (ntype) = cv_chain;
> > +  TYPE_AS_TYPE (ntype) = as_chain;
> > +
> > +  finish_cv_type (ntype);
> > +}
> > +
> >  /* Implement direct support for MEMBER_TYPE in GNU C++.
> >     May need to construct such a type if this is the first use.
> >     The TYPE is the type of the member.  The DOMAIN is the type
> > Index: gdbtypes.h
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/gdbtypes.h,v
> > retrieving revision 1.25
> > diff -u -p -r1.25 gdbtypes.h
> > --- gdbtypes.h	2002/01/20 19:42:04	1.25
> > +++ gdbtypes.h	2002/02/01 23:48:45
> > @@ -1062,6 +1062,8 @@ extern struct type *make_cv_type (int, i
> >  
> >  extern void finish_cv_type (struct type *);
> >  
> > +extern void replace_type (struct type *, struct type *);
> > +
> >  extern int address_space_name_to_int (char *);
> >  
> >  extern char *address_space_int_to_name (int);
> > Index: stabsread.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/stabsread.c,v
> > retrieving revision 1.23
> > diff -u -p -r1.23 stabsread.c
> > --- stabsread.c	2002/01/20 19:12:23	1.23
> > +++ stabsread.c	2002/02/01 23:48:46
> > @@ -2531,7 +2531,7 @@ again:
> >  	  }
> >  	else if (type_size >= 0 || is_string)
> >  	  {
> > -	    *type = *xtype;
> > +	    replace_type (type, xtype);
> >  	    TYPE_NAME (type) = NULL;
> >  	    TYPE_TAG_NAME (type) = NULL;
> >  	  }
> 

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