Re: [PATCH] Objective-C language support.

[Michael Snyder <msnyder@redhat.com>]

Adam Fedor wrote:
> 
> This patch adds Objective-C language support to gdb based upon a patch
> provided by Apple Computer Inc from their version of gdb. Note that the
> patch only contains changes to existing files. New files (objc-lang.h,
> objc-lang.c, objc-exp.y) and a gdb.objc testsuite directory are located at
> 
> ftp://ftp.gnustep.org/pub/gnustep/contrib/gdb-objc-patch.tar.gz

Adam, if no one objects in a few days, let's check in the following
subset of your valops.c changes.  This is transparent to anyone who
isn't debugging objective c (and for those who are, it simply allows
the use of "self" in place of "this").  Note that some of the valops.c
changes are not included in this approval.


>         * valops.c (value_of_local): New function.
>         (value_of_this): Use it.

> Index: gdb/valops.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/valops.c,v
> retrieving revision 1.72
> diff -u -p -r1.72 valops.c
> --- gdb/valops.c        14 Sep 2002 02:09:39 -0000      1.72
> +++ gdb/valops.c        17 Sep 2002 19:31:14 -0000
> @@ -3231,18 +3245,17 @@ value_full_object (struct value *argp, s
> 
> 
> 
> -/* C++: return the value of the class instance variable, if one exists.
> +/* Return the value of the local variable, if one exists.
>     Flag COMPLAIN signals an error if the request is made in an
>     inappropriate context.  */
> 
>  struct value *
> -value_of_this (int complain)
> +value_of_local (const char *name, int complain)
>  {
>    struct symbol *func, *sym;
>    struct block *b;
>    int i;
> -  static const char funny_this[] = "this";
> -  struct value *this;
> +  struct value * ret;
> 
>    if (selected_frame == 0)
>      {
> @@ -3256,7 +3269,7 @@ value_of_this (int complain)
>    if (!func)
>      {
>        if (complain)
> -       error ("no `this' in nameless context");
> +       error ("no %s in nameless context", name);
>        else
>         return 0;
>      }
> @@ -3266,26 +3279,39 @@ value_of_this (int complain)
>    if (i <= 0)
>      {
>        if (complain)
> -       error ("no args, no `this'");
> +       error ("no args, no %s", name);
>        else
>         return 0;
>      }
> 
>    /* Calling lookup_block_symbol is necessary to get the LOC_REGISTER
>       symbol instead of the LOC_ARG one (if both exist).  */
> -  sym = lookup_block_symbol (b, funny_this, NULL, VAR_NAMESPACE);
> +  sym = lookup_block_symbol (b, name, NULL, VAR_NAMESPACE);
>    if (sym == NULL)
>      {
>        if (complain)
> -       error ("current stack frame not in method");
> +       error ("current stack frame does not contain a variable named \"%s\"", name);
>        else
>         return NULL;
>      }
> 
> -  this = read_var_value (sym, selected_frame);
> -  if (this == 0 && complain)
> -    error ("`this' argument at unknown address");
> -  return this;
> +  ret = read_var_value (sym, selected_frame);
> +  if (ret == 0 && complain)
> +    error ("%s argument unreadable", name);
> +  return ret;
> +}
> +
> +/* C++/Objective-C: return the value of the class instance variable,
> +   if one exists.  Flag COMPLAIN signals an error if the request is
> +   made in an inappropriate context.  */
> +
> +struct value *
> +value_of_this (int complain)
> +{
> +  if (current_language->la_language == language_objc)
> +    return value_of_local ("self", complain);
> +  else
> +    return value_of_local ("this", complain);
>  }
> 
>  /* Create a slice (sub-string, sub-array) of ARRAY, that is LENGTH elements