This is the mail archive of the
gdb-patches@sources.redhat.com
mailing list for the GDB project.
Re: Trivial fix in value_sub
- From: Jim Blandy <jimb at redhat dot com>
- To: Jim Ingham <jingham at apple dot com>
- Cc: gdb-patches at sources dot redhat dot com
- Date: 04 Apr 2002 18:15:28 -0500
- Subject: Re: Trivial fix in value_sub
- References: <C207B8FE-4820-11D6-86BE-000393540DDC@apple.com>
Great. Please commit that.
Jim Ingham <jingham@apple.com> writes:
> Okay, how 'bout:
>
> 2002-04-04 Jim Ingham <jingham@apple.com>
>
> * valarith.c (find_size_for_pointer_math): New function,
> either returns
> the size for a pointer's target, returns 1 for void *, or errors for
> incomplete types.
> (value_add, value_sub): use find_size_for_pointer_math.
>
> Index: valarith.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/valarith.c,v
> retrieving revision 1.14
> diff -c -w -p -r1.14 valarith.c
> *** valarith.c 2002/03/27 21:35:35 1.14
> --- valarith.c 2002/04/04 23:05:12
> *************** static struct value *value_subscripted_r
> *** 43,54 ****
> void _initialize_valarith (void);
>
>
>
> struct value *
> value_add (struct value *arg1, struct value *arg2)
> {
> struct value *valint;
> struct value *valptr;
> ! register int len;
> struct type *type1, *type2, *valptrtype;
>
> COERCE_NUMBER (arg1);
> --- 43,92 ----
> void _initialize_valarith (void);
>
>
>
> + /* Given a pointer, return the size of its target.
> + If the pointer type is void *, then return 1.
> + If the target type is incomplete, then error out.
> + This isn't a general purpose function, but just a
> + helper for value_sub & value_add.
> + */
> +
> + static LONGEST
> + find_size_for_pointer_math (struct type *ptr_type)
> + {
> + LONGEST sz = -1;
> + struct type *ptr_target;
> +
> + ptr_target = check_typedef (TYPE_TARGET_TYPE (ptr_type));
> +
> + sz = TYPE_LENGTH (ptr_target);
> + if (sz == 0)
> + {
> + if (TYPE_CODE (ptr_type) == TYPE_CODE_VOID)
> + sz = 1;
> + else
> + {
> + char *name;
> +
> + name = TYPE_NAME (ptr_target);
> + if (name == NULL)
> + name = TYPE_TAG_NAME (ptr_target);
> + if (name == NULL)
> + error ("Cannot perform pointer math on incomplete types, "
> + "try casting to a known type, or void *.");
> + else
> + error ("Cannot perform pointer math on incomplete type
> \"%s\", "
> + "try casting to a known type, or void *.", name);
> + }
> + }
> + return sz;
> + }
> +
> struct value *
> value_add (struct value *arg1, struct value *arg2)
> {
> struct value *valint;
> struct value *valptr;
> ! LONGEST sz;
> struct type *type1, *type2, *valptrtype;
>
> COERCE_NUMBER (arg1);
> *************** value_add (struct value *arg1, struct va
> *** 77,88 ****
> valint = arg1;
> valptrtype = type2;
> }
> ! len = TYPE_LENGTH (check_typedef (TYPE_TARGET_TYPE
> (valptrtype)));
> ! if (len == 0)
> ! len = 1; /* For (void *) */
> retval = value_from_pointer (valptrtype,
> value_as_address (valptr)
> ! + (len * value_as_long (valint)));
> VALUE_BFD_SECTION (retval) = VALUE_BFD_SECTION (valptr);
> return retval;
> }
> --- 115,126 ----
> valint = arg1;
> valptrtype = type2;
> }
> !
> ! sz = find_size_for_pointer_math (valptrtype);
> !
> retval = value_from_pointer (valptrtype,
> value_as_address (valptr)
> ! + (sz * value_as_long (valint)));
> VALUE_BFD_SECTION (retval) = VALUE_BFD_SECTION (valptr);
> return retval;
> }
> *************** value_sub (struct value *arg1, struct va
> *** 104,110 ****
> if (TYPE_CODE (type2) == TYPE_CODE_INT)
> {
> /* pointer - integer. */
> ! LONGEST sz = TYPE_LENGTH (check_typedef (TYPE_TARGET_TYPE
> (type1)));
> return value_from_pointer (type1,
> (value_as_address (arg1)
> - (sz * value_as_long (arg2))));
> --- 142,149 ----
> if (TYPE_CODE (type2) == TYPE_CODE_INT)
> {
> /* pointer - integer. */
> ! LONGEST sz = find_size_for_pointer_math (type1);
> !
> return value_from_pointer (type1,
> (value_as_address (arg1)
> - (sz * value_as_long (arg2))));
>
> Jim
>
> >
> > Jim Ingham <jingham@apple.com> writes:
> >> Okay, so to be consistent, I throw errors in both value_add &
> >> value_sub. How about this:
> >
> > Superb! Could you move the "fix up my size or report an error" code
> > into a function instead of repeating it?
> >
> --
> Jim Ingham jingham@apple.com
> Developer Tools - gdb
> Apple Computer