Re: [patch] fix for c++/2416

[Michael Snyder <msnyder at specifix dot com>]

On Wed, 2008-02-27 at 13:03 -0500, Aleksandar Ristovski wrote:
> Hello,
> 
> As described in the bug report 2416, the problem is with casting to a reference. 
> The attached patch should fix this.
> 
> Testing on head, no change in pass rate encountered (probably suggesting there 
> is no test case for this - sample code in the bug report should be a good 
> starting point).

I don't understand the change in unpack_long.  
You want to treat structs and unions as longs?

Is this related to the reference-to-reference change?

> 2008-02-27  Aleksandar Ristovski <aristovski@qnx.com>
> 
> 	* eval.c (evaluate_subexp_standard): UNOP_CAST use
> 	value_cast_pointers when casting reference to reference. Print
> 	error when reference/non-reference mix.
> 	* value.c (value_as_address): Call coerce_array only on arrays.
> 	(unpack_long): Cover C++ cases TYPE_CODE_STRUCT and UNION.
> 
> 
> plain text document attachment (casting.diff)
> Index: gdb/eval.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/eval.c,v
> retrieving revision 1.80
> diff -u -p -r1.80 eval.c
> --- gdb/eval.c	4 Feb 2008 00:23:04 -0000	1.80
> +++ gdb/eval.c	27 Feb 2008 17:01:03 -0000
> @@ -1985,8 +1985,18 @@ evaluate_subexp_standard (struct type *e
>        arg1 = evaluate_subexp (type, exp, pos, noside);
>        if (noside == EVAL_SKIP)
>  	goto nosideret;
> -      if (type != value_type (arg1))
> -	arg1 = value_cast (type, arg1);
> +      if (type != value_type (arg1)) 
> +	{
> +	  if (TYPE_CODE (value_type (arg1)) == TYPE_CODE_REF
> +	      && TYPE_CODE (type) == TYPE_CODE_REF)
> +	    arg1 = value_cast_pointers (type, arg1);
> +	  else if (TYPE_CODE (value_type (arg1)) != TYPE_CODE_REF
> +		   && TYPE_CODE (type) != TYPE_CODE_REF)
> +	    arg1 = value_cast (type, arg1);
> +	  else /* We can not do much here.  */
> +	    error (_("Attempt to cast to reference type from non-reference "\
> +		     "type or vice versa."));
> +	}
>        return arg1;
>  
>      case UNOP_MEMVAL:
> Index: gdb/value.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/value.c,v
> retrieving revision 1.57
> diff -u -p -r1.57 value.c
> --- gdb/value.c	18 Jan 2008 17:07:40 -0000	1.57
> +++ gdb/value.c	27 Feb 2008 17:01:03 -0000
> @@ -1039,7 +1039,8 @@ value_as_address (struct value *val)
>        || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
>      return VALUE_ADDRESS (val);
>  
> -  val = coerce_array (val);
> +  if (TYPE_CODE (value_type (val)) == TYPE_CODE_ARRAY)
> +    val = coerce_array (val);
>  
>    /* Some architectures (e.g. Harvard), map instruction and data
>       addresses onto a single large unified address space.  For
> @@ -1120,6 +1121,8 @@ unpack_long (struct type *type, const gd
>      case TYPE_CODE_CHAR:
>      case TYPE_CODE_RANGE:
>      case TYPE_CODE_MEMBERPTR:
> +    case TYPE_CODE_STRUCT:
> +    case TYPE_CODE_UNION:
>        if (nosign)
>  	return extract_unsigned_integer (valaddr, len);
>        else