This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [patch v4 13/24] record-btrace, frame: supply target-specific unwinder
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: Markus Metzger <markus dot t dot metzger at intel dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Sun, 18 Aug 2013 21:07:42 +0200
- Subject: Re: [patch v4 13/24] record-btrace, frame: supply target-specific unwinder
- References: <1372842874-28951-1-git-send-email-markus dot t dot metzger at intel dot com> <1372842874-28951-14-git-send-email-markus dot t dot metzger at intel dot com>
On Wed, 03 Jul 2013 11:14:23 +0200, Markus Metzger wrote:
> Supply a target-specific frame unwinder for the record-btrace target that does
> not allow unwinding while replaying.
>
> 2013-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
> Markus Metzger <markus.t.metzger@intel.com>
>
> gdb/
> * record-btrace.c: Include frame-unwind.h.
> (record_btrace_frame_unwind_stop_reason,
> record_btrace_frame_this_id, record_btrace_frame_prev_register,
> record_btrace_frame_sniffer, record_btrace_frame_unwind):
> New.
> (init_record_btrace_ops): Install it.
>
>
> ---
> gdb/record-btrace.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 66 insertions(+), 0 deletions(-)
>
> diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
> index e9c0801..cb1f3bb 100644
> --- a/gdb/record-btrace.c
> +++ b/gdb/record-btrace.c
> @@ -33,6 +33,7 @@
> #include "symtab.h"
> #include "filenames.h"
> #include "regcache.h"
> +#include "frame-unwind.h"
>
> /* The target_ops of record-btrace. */
> static struct target_ops record_btrace_ops;
> @@ -844,6 +845,70 @@ record_btrace_prepare_to_store (struct target_ops *ops,
> }
> }
>
> +/* Implement stop_reason method for record_btrace_frame_unwind. */
> +
> +static enum unwind_stop_reason
> +record_btrace_frame_unwind_stop_reason (struct frame_info *this_frame,
> + void **this_cache)
> +{
> + return UNWIND_UNAVAILABLE;
> +}
> +
> +/* Implement this_id method for record_btrace_frame_unwind. */
> +
> +static void
> +record_btrace_frame_this_id (struct frame_info *this_frame, void **this_cache,
> + struct frame_id *this_id)
> +{
> + /* Leave there the outer_frame_id value. */
> +}
> +
> +/* Implement prev_register method for record_btrace_frame_unwind. */
> +
> +static struct value *
> +record_btrace_frame_prev_register (struct frame_info *this_frame,
> + void **this_cache,
> + int regnum)
> +{
> + throw_error (NOT_AVAILABLE_ERROR,
> + _("Registers are not available in btrace record history"));
> +}
> +
> +/* Implement sniffer method for record_btrace_frame_unwind. */
> +
> +static int
> +record_btrace_frame_sniffer (const struct frame_unwind *self,
> + struct frame_info *this_frame,
> + void **this_cache)
> +{
> + struct thread_info *tp;
> + struct btrace_thread_info *btinfo;
> + struct btrace_insn_iterator *replay;
> +
> + /* This doesn't seem right. Yet, I don't see how I could get from a frame
> + to its thread. */
That's OK. Either remove the comment or:
/* THIS_FRAME does not contain a reference to its thread. */
> + tp = find_thread_ptid (inferior_ptid);
> + if (tp == NULL)
> + return 0;
gdb_assert (tp != NULL);
> +
> + return btrace_is_replaying (tp);
> +}
> +
> +/* btrace recording does not store previous memory content, neither the stack
> + frames content. Any unwinding would return errorneous results as the stack
> + contents no longer matches the changed PC value restored from history.
> + Therefore this unwinder reports any possibly unwound registers as
> + <unavailable>. */
> +
> +static const struct frame_unwind record_btrace_frame_unwind =
> +{
> + NORMAL_FRAME,
> + record_btrace_frame_unwind_stop_reason,
> + record_btrace_frame_this_id,
> + record_btrace_frame_prev_register,
> + NULL,
> + record_btrace_frame_sniffer
> +};
> /* Initialize the record-btrace target ops. */
>
> static void
> @@ -874,6 +939,7 @@ init_record_btrace_ops (void)
> ops->to_fetch_registers = record_btrace_fetch_registers;
> ops->to_store_registers = record_btrace_store_registers;
> ops->to_prepare_to_store = record_btrace_prepare_to_store;
> + ops->to_get_unwinder = &record_btrace_frame_unwind;
> ops->to_stratum = record_stratum;
> ops->to_magic = OPS_MAGIC;
> }
> --
> 1.7.1