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Re: [PATCH]: Add expected type to hand_function_call




Elena Zannoni wrote:
Adam Fedor writes:
> This patch adds a parameter to hand_function_call that can be used to > check the type of the function return. This is used often with > Objective-C as this information is known by the runtime and can be used > to check the validity of the function.
> > 2002-11-24 Adam Fedor <fedor at gnu dot org>
> > * valops.c (find_function_addr): Make non-static.
> (hand_function_call): Add expect_type arg, use it to check
> return type of function (updated by Klee Dienes <kdienes at apple dot com>).
> (call_function_by_hand): Update for change in hand_function_call.
> (call_function_by_hand_expecting_type): New function.
> * value.h (find_function_addr,
> call_function_by_hand_expecting_type): Declare.
> > Index: valops.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/valops.c,v
> retrieving revision 1.79
> diff -u -p -r1.79 valops.c
> --- valops.c 7 Nov 2002 02:45:27 -0000 1.79
> +++ valops.c 25 Nov 2002 02:50:17 -0000
> @@ -48,7 +48,6 @@ extern int overload_debug;
> static int typecmp (int staticp, int varargs, int nargs,
> struct field t1[], struct value *t2[]);
> > -static CORE_ADDR find_function_addr (struct value *, struct type **);
> static struct value *value_arg_coerce (struct value *, struct type *, int);
> > > @@ -1228,7 +1227,7 @@ value_arg_coerce (struct value *arg, str
> /* Determine a function's address and its return type from its value.
> Calls error() if the function is not valid for calling. */
> > -static CORE_ADDR
> +CORE_ADDR
> find_function_addr (struct value *function, struct type **retval_type)
> {
> register struct type *ftype = check_typedef (VALUE_TYPE (function));
> @@ -1296,7 +1295,8 @@ find_function_addr (struct value *functi
> ARGS is modified to contain coerced values. */
> > static struct value *
> -hand_function_call (struct value *function, int nargs, struct value **args)
> +hand_function_call (struct value *function, struct type *expect_type,
> + int nargs, struct value **args)
> {
> register CORE_ADDR sp;
> register int i;
> @@ -1342,6 +1342,17 @@ hand_function_call (struct value *functi
> if (!target_has_execution)
> noprocess ();
> > + funaddr = find_function_addr (function, &value_type);
> + CHECK_TYPEDEF (value_type);
> +
> + if ((value_type == NULL) || (TYPE_CODE (value_type) == TYPE_CODE_ERROR))
> + value_type = expect_type;
> +
> + if ((value_type == NULL) || (TYPE_CODE (value_type) == TYPE_CODE_ERROR))
> + error ("Unable to call function at 0x%lx: no return type information available.\n"
> + "To call this function anyway, you can cast the return type explicitly (e.g. 'print (float) fabs (3.0)')",
> + (unsigned long) funaddr);
> +


Could this code be moved into the new function? This way you could leave
hand_function_call alone, and just have 2 wrappers call_function_by_hand and
call_function_by_hand_expecting_type.


It's possible, but doing that would probably make it more contrived, and I would still have to change hand_function_call to pass in the value_type. Really, if I just remove the error message for NULL value_type, the entire change just consists of one if statement:


if ((value_type == NULL) || (TYPE_CODE (value_type) == TYPE_CODE_ERROR))
    value_type = expect_type;

Which is pretty benign.



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