From: "Metzger, Markus T" <markus.t.metzger@intel.com>
To: Pedro Alves <palves@redhat.com>,
"jan.kratochvil@redhat.com" <jan.kratochvil@redhat.com>
Cc: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>,
Eli Zaretskii <eliz@gnu.org>
Subject: RE: [patch v8 24/24] record-btrace: add (reverse-)stepping support
Date: Tue, 17 Dec 2013 15:48:00 -0000 [thread overview]
Message-ID: <A78C989F6D9628469189715575E55B230AA39911@IRSMSX104.ger.corp.intel.com> (raw)
In-Reply-To: <A78C989F6D9628469189715575E55B230AA39866@IRSMSX104.ger.corp.intel.com>
> -----Original Message-----
> From: Metzger, Markus T
> Sent: Tuesday, December 17, 2013 4:06 PM
> To: Pedro Alves
> I'm beginning to wonder if we should actually adjust the PC for
> btrace replay. The way I interpret the function, we got a SIGTRAP
> for executing the breakpoint instruction. The PC is after the breakpoint
> instruction, so it is one byte after the actual breakpoint location. We're
> now trying to undo the execution of the breakpoint instruction.
> Is this correct?
>
> In that case, we shouldn't adjust the PC since we did not execute
> the breakpoint instruction in the trace. We just asked whether there
> is a breakpoint at the current location.
>
> This seems to be different for s/w record. This is the first time, I need
> to distinguish between the different record targets.
The s/w record target also does not execute the breakpoint instruction.
It increments the PC by gdbarch_decr_pc_after_break () when it finds a
s/w breakpoint at the current location.
I wonder why they are doing that. Is this a workaround that was considered
less intrusive than what I am proposing below? Or are there more places
in GDB that expect the PC to be past the breakpoint instruction?
I could do the same, of course. Not sure which version is more desirable.
> I would add a new target method to_omit_pc_after_break_adjustment
> that would default to false if not present. The btrace record target will
> provide it and return true if we're replaying.
>
> OK with that?
Regards,
Markus.
Intel GmbH
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next prev parent reply other threads:[~2013-12-17 15:48 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-12 9:15 [patch v8 00/24] record-btrace: reverse Markus Metzger
2013-12-12 9:15 ` [patch v8 16/24] record-btrace, frame: supply target-specific unwinder Markus Metzger
2013-12-12 9:15 ` [patch v8 14/24] record-btrace: supply register target methods Markus Metzger
2013-12-12 9:15 ` [patch v8 03/24] gdbarch: add instruction predicate methods Markus Metzger
2013-12-12 9:15 ` [patch v8 01/24] btrace, linux: fix memory leak when reading branch trace Markus Metzger
2013-12-12 9:16 ` [patch v8 07/24] record-btrace: fix insn range in function call history Markus Metzger
2013-12-12 9:16 ` [patch v8 23/24] record-btrace: show trace from enable location Markus Metzger
2013-12-13 19:50 ` Pedro Alves
2013-12-16 12:57 ` Metzger, Markus T
2013-12-16 19:41 ` Pedro Alves
2013-12-17 13:20 ` Metzger, Markus T
2013-12-17 16:59 ` Pedro Alves
2013-12-12 9:16 ` [patch v8 22/24] btrace, gdbserver: read branch trace incrementally Markus Metzger
2013-12-13 19:46 ` Pedro Alves
2013-12-16 12:47 ` Metzger, Markus T
2013-12-16 19:23 ` Pedro Alves
2013-12-12 9:16 ` [patch v8 17/24] record-btrace: provide xfer_partial target method Markus Metzger
2013-12-13 18:43 ` Pedro Alves
2013-12-16 10:53 ` Metzger, Markus T
2013-12-16 19:16 ` Pedro Alves
2013-12-17 11:58 ` Metzger, Markus T
2013-12-17 16:56 ` Pedro Alves
2013-12-18 9:26 ` Metzger, Markus T
2013-12-18 10:39 ` Pedro Alves
2013-12-12 9:16 ` [patch v8 19/24] record-btrace: provide target_find_new_threads method Markus Metzger
2013-12-12 9:16 ` [patch v8 05/24] frame: artificial frame id's Markus Metzger
2013-12-12 19:39 ` Pedro Alves
2013-12-12 19:55 ` Jan Kratochvil
2013-12-13 8:04 ` Metzger, Markus T
2013-12-13 11:27 ` Jan Kratochvil
2013-12-13 11:42 ` Metzger, Markus T
2013-12-13 12:09 ` Pedro Alves
2013-12-13 13:01 ` Metzger, Markus T
2013-12-13 15:44 ` Pedro Alves
2013-12-13 17:51 ` Pedro Alves
2013-12-18 13:30 ` Metzger, Markus T
2013-12-12 9:16 ` [patch v8 04/24] frame: add frame_is_tailcall function Markus Metzger
2013-12-12 9:16 ` [patch v8 11/24] record-btrace: make ranges include begin and end Markus Metzger
2013-12-13 17:56 ` Pedro Alves
2013-12-12 9:16 ` [patch v8 21/24] record-btrace: extend unwinder Markus Metzger
2013-12-13 19:45 ` Pedro Alves
2013-12-16 12:42 ` Metzger, Markus T
2013-12-16 19:22 ` Pedro Alves
2013-12-17 12:56 ` Metzger, Markus T
2013-12-12 9:16 ` [patch v8 20/24] record-btrace: add record goto target methods Markus Metzger
2013-12-12 9:16 ` [patch v8 12/24] btrace: add replay position to btrace thread info Markus Metzger
2013-12-12 9:16 ` [patch v8 18/24] record-btrace: add to_wait and to_resume target methods Markus Metzger
2013-12-12 9:16 ` [patch v8 06/24] btrace: change branch trace data structure Markus Metzger
2013-12-12 9:16 ` [patch v8 02/24] btrace: uppercase btrace_read_type Markus Metzger
2013-12-12 9:16 ` [patch v8 10/24] record-btrace: optionally indent function call history Markus Metzger
2013-12-12 9:16 ` [patch v8 09/24] btrace: increase buffer size Markus Metzger
2013-12-12 9:16 ` [patch v8 08/24] record-btrace: start counting at one Markus Metzger
2013-12-12 9:16 ` [patch v8 13/24] target: add ops parameter to to_prepare_to_store method Markus Metzger
2013-12-12 9:16 ` [patch v8 15/24] frame, backtrace: allow targets to supply a frame unwinder Markus Metzger
2013-12-13 18:27 ` Pedro Alves
2013-12-16 9:18 ` Metzger, Markus T
2013-12-16 19:02 ` Pedro Alves
2013-12-17 8:26 ` Metzger, Markus T
2013-12-17 9:48 ` Pedro Alves
2013-12-12 9:16 ` [patch v8 24/24] record-btrace: add (reverse-)stepping support Markus Metzger
2013-12-12 16:36 ` Eli Zaretskii
2013-12-13 19:22 ` Pedro Alves
2013-12-16 15:56 ` Metzger, Markus T
2013-12-16 20:30 ` Pedro Alves
2013-12-17 14:14 ` Metzger, Markus T
2013-12-17 15:07 ` Metzger, Markus T
2013-12-17 15:48 ` Metzger, Markus T [this message]
2013-12-17 20:41 ` Pedro Alves
2013-12-17 20:34 ` Pedro Alves
2013-12-17 20:07 ` Pedro Alves
2013-12-18 9:44 ` Metzger, Markus T
2013-12-12 14:07 ` [patch v8 00/24] record-btrace: reverse Jan Kratochvil
2013-12-12 14:19 ` Metzger, Markus T
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