Re: RTTI type improvement for (was: "Re: set print object on should affect MI varobjs (PR mi/13393)")

Jan Kratochvil
2012-01-09T14:41:59Z

Hello Anton,

On Fri, 06 Jan 2012 16:47:08 +0100, xgsa wrote:
> > That change to value_rtti_indirect_type would be easier to read if it was
> > a separate patch.
>
> This is the first part of my previous patch that contains the change
> to value_rtti_indirect_type. The second part requires this one to be
> applied, so I'll provide it after commit.

Unfortunately we cannot yet check it in while waiting for the copyright
paperwork. But sure you can base the other patch on top of this one.

> Here is an example of what this patch fixes:
[...]
> The "whatis ri" command fails with message:
> "Attempt to take contents of a non-pointer value.".
> The "whatis pi" command does not respect cv-qualifiers:
> type = /* real type = Derived * */
> const Base *

I do not see any change with this patch in the results of your testcase
gdb.mi/mi-var-rtti.exp . Regressions in the future are better evaluated when
one sees the testcase and associated code which it breaks. A separate
testcase for this patch would be nice but I assume the full changes require
this functionality so it gets tested anyway.

> gdb/ChangeLog:
>
> 2012-01-06 Anton Gorenkov <xgsa@yandex.ru>
>
> * c-valprint.c (c_value_print): Use value_rtti_indirect_type
> instead of value_rtti_target_type.
> * eval.c (evaluate_subexp_standard): Use value_rtti_indirect_type
> instead of value_rtti_target_type.
> * typeprint.c (whatis_exp): Use value_rtti_indirect_type instead of
> value_rtti_target_type.
> * valops.c (value_ind): Extract function readjust_indirect_value_type.
> (value_rtti_indirect_type): The replacement for value_rtti_target_type.

Here really should be value_rtti_target_type in parens, like:
(value_rtti_target_type): Rename to ...
(value_rtti_indirect_type): ... here and make it indirect. Update
function comment.

> * value.c (readjust_indirect_value_type): New function.
> (coerce_ref): Support for enclosing type setting for references
> with readjust_indirect_value_type.

> * value.h (readjust_value_type): The replacement for
> value_rtti_target_type.

Use:
* value.h (readjust_value_type): New declaration.
(value_rtti_target_type): Rename to ...
(value_rtti_indirect_type): ... here.

> diff --git a/gdb/c-valprint.c b/gdb/c-valprint.c
> index 3461b08..e2e2792 100644
> --- a/gdb/c-valprint.c
> +++ b/gdb/c-valprint.c
> @@ -698,22 +698,13 @@ c_value_print (struct value *val, struct ui_file *stream,
>
> if (value_entirely_available (val))
> {
> - real_type = value_rtti_target_type (val, &full, &top, &using_enc);
> + real_type = value_rtti_indirect_type (val, &full, &top,
> + &using_enc);
> if (real_type)
> {
> /* RTTI entry found. */
> - if (TYPE_CODE (type) == TYPE_CODE_PTR)
> - {
> - /* Create a pointer type pointing to the real
> - type. */
> - type = lookup_pointer_type (real_type);
> - }
> - else
> - {
> - /* Create a reference type referencing the real
> - type. */
> - type = lookup_reference_type (real_type);
> - }
> + type = real_type;
> +
> /* Need to adjust pointer value. */
> val = value_from_pointer (type, value_as_address (val) - top);
>
> diff --git a/gdb/eval.c b/gdb/eval.c
> index 5d758d1..10606a8 100644
> --- a/gdb/eval.c
> +++ b/gdb/eval.c
> @@ -1990,16 +1990,10 @@ evaluate_subexp_standard (struct type *expect_type,
> if (opts.objectprint && TYPE_TARGET_TYPE(type)
> && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
> {
> - real_type = value_rtti_target_type (arg1, &full, &top, &using_enc);
> + real_type = value_rtti_indirect_type (arg1, &full, &top,

This line should indent by tabs, not spaces. Sure a nitpick, no problem.
Do not care if the old code was wrongly using spaces.

> + &using_enc);
> if (real_type)
> - {
> - if (TYPE_CODE (type) == TYPE_CODE_PTR)
> - real_type = lookup_pointer_type (real_type);
> - else
> - real_type = lookup_reference_type (real_type);
> -
> arg1 = value_cast (real_type, arg1);
> - }
> }
> }
>
> diff --git a/gdb/typeprint.c b/gdb/typeprint.c
> index cf4158d..6546c98 100644
> --- a/gdb/typeprint.c
> +++ b/gdb/typeprint.c
> @@ -140,16 +140,7 @@ whatis_exp (char *exp, int show)
> if (((TYPE_CODE (type) == TYPE_CODE_PTR)
> || (TYPE_CODE (type) == TYPE_CODE_REF))
> && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
> - {
> - real_type = value_rtti_target_type (val, &full, &top, &using_enc);
> - if (real_type)
> - {
> - if (TYPE_CODE (type) == TYPE_CODE_PTR)
> - real_type = lookup_pointer_type (real_type);
> - else
> - real_type = lookup_reference_type (real_type);
> - }
> - }
> + real_type = value_rtti_indirect_type (val, &full, &top, &using_enc);
> else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
> real_type = value_rtti_type (val, &full, &top, &using_enc);
> }
> diff --git a/gdb/valops.c b/gdb/valops.c
> index cb39677..2bc02f3 100644
> --- a/gdb/valops.c
> +++ b/gdb/valops.c
> @@ -1774,15 +1774,7 @@ value_ind (struct value *arg1)
> (value_as_address (arg1)
> - value_pointed_to_offset (arg1)));
>
> - /* Re-adjust type. */
> - deprecated_set_value_type (arg2, TYPE_TARGET_TYPE (base_type));
> - /* Add embedding info. */
> - set_value_enclosing_type (arg2, enc_type);
> - set_value_embedded_offset (arg2, value_pointed_to_offset (arg1));
> -
> - /* We may be pointing to an object of some derived type. */
> - arg2 = value_full_object (arg2, NULL, 0, 0, 0);
> - return arg2;
> + return readjust_indirect_value_type (arg2, enc_type, base_type, arg1);
> }
>
> error (_("Attempt to take contents of a non-pointer value."));
> @@ -3528,21 +3520,48 @@ value_maybe_namespace_elt (const struct type *curtype,
> return result;
> }
>
> -/* Given a pointer value V, find the real (RTTI) type of the object it
> - points to.
> +/* Given a pointer or a reference value V, find its real (RTTI) type.
>
> Other parameters FULL, TOP, USING_ENC as with value_rtti_type()
> and refer to the values computed for the object pointed to. */
>
> struct type *
> -value_rtti_target_type (struct value *v, int *full,
> - int *top, int *using_enc)
> +value_rtti_indirect_type (struct value *v, int *full,
> + int *top, int *using_enc)
> {
> struct value *target;
> + struct type *type, *real_type, *target_type;
> +
> + type = value_type (v);
> + type = check_typedef (type);
> + if (TYPE_CODE (type) == TYPE_CODE_REF)
> + target = coerce_ref (v);
> + else if (TYPE_CODE (type) == TYPE_CODE_PTR)
> + target = value_ind (v);
> + else
> + return NULL;
>
> - target = value_ind (v);
> + real_type = value_rtti_type (target, full, top, using_enc);
> +
> + if (real_type)
> + {
> + /* Copy qualifiers to the referenced object. */
> + target_type = value_type (target);
> + real_type = make_cv_type (TYPE_CONST (target_type),
> + TYPE_VOLATILE (target_type), real_type, NULL);
> + if (TYPE_CODE (type) == TYPE_CODE_REF)
> + real_type = lookup_reference_type (real_type);
> + else if (TYPE_CODE (type) == TYPE_CODE_PTR)
> + real_type = lookup_pointer_type (real_type);
> + else
> + internal_error (__FILE__, __LINE__, _("Unexpected value type."));

Here should be tabs for indentation, 3 times.

> +
> + /* Copy qualifiers to the pointer/reference. */
> + real_type = make_cv_type (TYPE_CONST (type), TYPE_VOLATILE (type),
> + real_type, NULL);
> + }
>
> - return value_rtti_type (target, full, top, using_enc);
> + return real_type;
> }
>
> /* Given a value pointed to by ARGP, check its real run-time type, and
> diff --git a/gdb/value.c b/gdb/value.c
> index d263d0c..c78e489 100644
> --- a/gdb/value.c
> +++ b/gdb/value.c
> @@ -3109,11 +3109,30 @@ coerce_ref_if_computed (const struct value *arg)
> return funcs->coerce_ref (arg);
> }
>
> +/* Look at value.h for description. */
> +
> +struct value *
> +readjust_indirect_value_type (struct value *value, struct type *enc_type,
> + struct type *original_type,
> + struct value *original_value)
> +{
> + /* Re-adjust type. */
> + deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
> +
> + /* Add embedding info. */
> + set_value_enclosing_type (value, enc_type);
> + set_value_embedded_offset (value, value_pointed_to_offset (original_value));
> +
> + /* We may be pointing to an object of some derived type. */
> + return value_full_object (value, NULL, 0, 0, 0);
> +}
> +
> struct value *
> coerce_ref (struct value *arg)
> {
> struct type *value_type_arg_tmp = check_typedef (value_type (arg));
> struct value *retval;
> + struct type *enc_type;
>
> retval = coerce_ref_if_computed (arg);
> if (retval)
> @@ -3122,9 +3141,13 @@ coerce_ref (struct value *arg)
> if (TYPE_CODE (value_type_arg_tmp) != TYPE_CODE_REF)
> return arg;
>
> - return value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),
> - unpack_pointer (value_type (arg),
> - value_contents (arg)));
> + enc_type = check_typedef (value_enclosing_type (arg));
> + enc_type = TYPE_TARGET_TYPE (enc_type);
> +
> + retval = value_at_lazy (enc_type,
> + unpack_pointer (value_type (arg),
> + value_contents (arg)));
> + return readjust_indirect_value_type (retval, enc_type, value_type_arg_tmp, arg);

Line has more than 80 characters.

> }
>
> struct value *
> diff --git a/gdb/value.h b/gdb/value.h
> index d2c58ec..679192f 100644
> --- a/gdb/value.h
> +++ b/gdb/value.h
> @@ -353,6 +353,19 @@ extern short *deprecated_value_regnum_hack (struct value *);
>
> extern struct value *coerce_ref_if_computed (const struct value *arg);
>
> +/* Setup a new value type and enclosing value type for dereferenced value VALUE.
> + ENC_TYPE is the new enclosing type that should be set. ORIGINAL_TYPE and
> + ORIGINAL_VALUE are the type and value of the original reference or pointer.
> +
> + Note, that VALUE is modified by this function.
> +
> + It is a common implementation for coerce_ref and value_ind. */
> +
> +extern struct value *
> +readjust_indirect_value_type (struct value *value, struct type *enc_type,
> + struct type *original_type,
> + struct value *original_value);
> +
> /* Convert a REF to the object referenced. */
>
> extern struct value *coerce_ref (struct value *value);
> @@ -617,8 +630,8 @@ extern struct value *value_primitive_field (struct value *arg1, int offset,
> struct type *arg_type);
>
>
> -extern struct type *value_rtti_target_type (struct value *, int *, int *,
> - int *);
> +extern struct type *value_rtti_indirect_type (struct value *, int *, int *,
> + int *);
>
> extern struct value *value_full_object (struct value *, struct type *, int,
> int, int);

In general OK, prepared for a check-in.

Thanks,
Jan