From: "Agovic, Sanimir" <sanimir.agovic@intel.com>
To: 'Pedro Alves' <palves@redhat.com>
Cc: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Subject: RE: [PATCH 06/10] vla: update type from newly created value
Date: Wed, 20 Nov 2013 13:08:00 -0000 [thread overview]
Message-ID: <0377C58828D86C4588AEEC42FC3B85A7176B82F7@IRSMSX105.ger.corp.intel.com> (raw)
In-Reply-To: <528C8F1E.2080309@redhat.com>
> -----Original Message-----
> From: Pedro Alves [mailto:palves@redhat.com]
> Sent: Wednesday, November 20, 2013 11:30 AM
> To: Agovic, Sanimir
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH 06/10] vla: update type from newly created value
>
> On 10/21/2013 03:40 PM, Sanimir Agovic wrote:
> > Constructing a value based on a type and address might change the type
> > of the newly constructed value.
>
> OOC (and for the archives), why's that? Where does that occur?
>
Since dwarf3 certain attributes e.g upper/lower bound may be computed
dynamically. To support such attributes with the current gdb type-system
we require such types to be "normalized". This means types with dynamic
properties are converted to types with static properties.
To successful convert a type with dynamic properties into one with static
properties access to inferior memory is needed. Therefore we hooked into
the following value constructors
value_at/value_at_lazy/value_from_contents_and_address
as they require an inferior address in addition to a type to instantiate
a value. IIF the passed type has dynamic properties we resolve the bounds
and thus change the type.
Given the following statement:
struct value *val = value_at (my_vla_type, at_address);
Before this was always true:
TYPE_LENGTH (value_type (val)) == TYPE_LENGTH (my_vla_type)
This is not the case after applying this (vla-c00) patch series. Type
normalization is done in the mentioned value constructors and might
change the value type, therefore we need to re-fetch the type from
the constructed value.
I hope this makes sense.
> > Thus re-fetch type via value_type to ensure
> > we have the correct type at hand.
>
> --
> Pedro Alves
Intel GmbH
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next prev parent reply other threads:[~2013-11-20 12:47 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-21 14:40 C99 variable length array support Sanimir Agovic
2013-10-21 14:40 ` [PATCH 07/10] test: evaluate pointers to C99 vla correctly Sanimir Agovic
2013-11-07 20:57 ` Tom Tromey
2013-11-08 6:37 ` Tom Tromey
2013-11-07 21:14 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 05/10] vla: allow side effects for sizeof argument Sanimir Agovic
2013-10-24 19:55 ` Tom Tromey
2013-10-25 8:13 ` Agovic, Sanimir
2013-10-28 21:00 ` Tom Tromey
2013-11-18 9:37 ` Agovic, Sanimir
2013-11-18 15:56 ` Tom Tromey
2013-11-20 12:18 ` Agovic, Sanimir
2013-11-19 17:08 ` Pedro Alves
2013-11-20 12:47 ` Agovic, Sanimir
2013-11-20 13:24 ` Pedro Alves
2013-10-21 14:40 ` [PATCH 02/10] type: add c99 variable length array support Sanimir Agovic
2013-11-07 19:02 ` Tom Tromey
2013-11-19 15:31 ` Agovic, Sanimir
2013-11-22 20:00 ` Tom Tromey
2013-11-27 17:08 ` Agovic, Sanimir
[not found] ` <0377C58828D86C4588AEEC42FC3B85A7176BC3DE@IRSMSX105.ger.corp.intel.com>
2013-11-27 17:15 ` Agovic, Sanimir
2013-11-07 19:10 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 03/10] vla: enable sizeof operator to work with variable length arrays Sanimir Agovic
2013-11-07 19:10 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 10/10] test: add mi vla test Sanimir Agovic
2013-11-07 21:31 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 09/10] test: basic c99 vla tests Sanimir Agovic
2013-11-07 21:23 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 06/10] vla: update type from newly created value Sanimir Agovic
2013-11-07 20:56 ` Tom Tromey
2013-11-20 7:56 ` Agovic, Sanimir
2013-11-20 11:02 ` Pedro Alves
2013-11-20 13:08 ` Agovic, Sanimir [this message]
2013-11-21 18:50 ` Pedro Alves
2013-11-23 19:27 ` Doug Evans
2013-10-21 14:40 ` [PATCH 04/10] vla: enable sizeof operator for indirection Sanimir Agovic
2013-11-07 19:57 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 08/10] test: multi-dimensional c99 vla Sanimir Agovic
2013-11-07 21:19 ` Tom Tromey
2013-10-21 14:40 ` [PATCH 01/10] vla: introduce new bound type abstraction adapt uses Sanimir Agovic
2013-11-07 19:00 ` Tom Tromey
2013-11-18 11:15 ` Agovic, Sanimir
2013-11-21 18:52 ` C99 variable length array support Pedro Alves
2013-11-21 19:01 ` Pedro Alves
2013-11-21 19:10 ` Pedro Alves
2013-11-22 10:53 ` Agovic, Sanimir
2013-11-22 12:35 ` Pedro Alves
2013-11-22 17:06 ` Agovic, Sanimir
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