Re: [PATCH]: Add expected type to hand_function_call

[Elena Zannoni <ezannoni at redhat dot com>]

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.

elena


 >    /* Create a cleanup chain that contains the retbuf (buffer
 >       containing the register values).  This chain is create BEFORE the
 >       inf_status chain so that the inferior status can cleaned up
 > @@ -1428,9 +1439,6 @@ hand_function_call (struct value *functi
 >       a SIZEOF_DUMMY1 (via SIZEOF_CALL_DUMMY_WORDS) such that all local
 >       alignment requirements are met.  */
 >  
 > -  funaddr = find_function_addr (function, &value_type);
 > -  CHECK_TYPEDEF (value_type);
 > -
 >    {
 >      struct block *b = block_for_pc (funaddr);
 >      /* If compiled without -g, assume GCC 2.  */
 > @@ -1891,7 +1899,22 @@ call_function_by_hand (struct value *fun
 >  {
 >    if (CALL_DUMMY_P)
 >      {
 > -      return hand_function_call (function, nargs, args);
 > +      return hand_function_call (function, NULL, nargs, args);
 > +    }
 > +  else
 > +    {
 > +      error ("Cannot invoke functions on this machine.");
 > +    }
 > +}
 > +
 > +struct value *
 > +call_function_by_hand_expecting_type (struct value *function, 
 > +				      struct type *expect_type,
 > +                                      int nargs, struct value **args)
 > +{
 > +  if (CALL_DUMMY_P)
 > +    {
 > +      return hand_function_call (function, expect_type, nargs, args);
 >      }
 >    else
 >      {
 > Index: value.h
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/value.h,v
 > retrieving revision 1.37
 > diff -u -p -r1.37 value.h
 > --- value.h	14 Oct 2002 02:02:42 -0000	1.37
 > +++ value.h	25 Nov 2002 02:50:17 -0000
 > @@ -548,6 +548,10 @@ extern struct value *value_slice (struct
 >  extern struct value *call_function_by_hand (struct value *, int,
 >  					    struct value **);
 >  
 > +extern struct value *call_function_by_hand_expecting_type (struct value *,
 > +						       struct type *, int,
 > +						       struct value **);
 > +
 >  extern int default_coerce_float_to_double (struct type *, struct type *);
 >  
 >  extern int standard_coerce_float_to_double (struct type *, struct type *);
 > @@ -565,6 +569,8 @@ extern struct value *value_allocate_spac
 >  extern CORE_ADDR default_push_arguments (int nargs, struct value ** args,
 >  					 CORE_ADDR sp, int struct_return,
 >  					 CORE_ADDR struct_addr);
 > +
 > +extern CORE_ADDR find_function_addr (struct value *, struct type **);
 >  
 >  extern struct value *value_of_local (const char *name, int complain);
 >