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From: Mark Wielaard <mark@klomp.org>
To: Omar Sandoval <osandov@osandov.com>, elfutils-devel@sourceware.org
Subject: Re: [PATCH 4/5] libdwfl: cache Dwfl_Module and Dwarf_Frame for Dwfl_Frame
Date: Wed, 30 Oct 2019 13:04:00 -0000	[thread overview]
Message-ID: <7be679675894550820b63e7c08a5495d06ac49a8.camel@klomp.org> (raw)
In-Reply-To: <bfd7a24101b3b6b75fd3270dbf4a58e8a15545d8.1570438723.git.osandov@fb.com>

Hi Omar,

On Mon, 2019-10-07 at 02:05 -0700, Omar Sandoval wrote:
> The next change will need to have the Dwarf_Frame readily available, so
> rather than finding it again every time, let's cache it for reuse. The
> CFI frame can also be useful to clients of libdwfl, so add
> dwfl_frame_dwarf_frame to get it. Similarly, the Dwfl_Module is also
> frequently needed in conjunction with the frame, so cache it and add
> dwfl_frame_module.

I can see how this is useful. But it seems the Dwarf_Frame is only
cached when __libdwfl_frame_unwind is called. Which I believe isn't
done for the initial frame. Also it isn't clear how to propagate any
errors when NULL is returned. Maybe dwfl_frame_dwarf_frame () should
check first to see if frame is NULL and then call lookup the CFI and
call dwarf_cfi_addrframe if not?

Thanks,

Mark

  reply	other threads:[~2019-10-30 13:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07  9:05 [PATCH 0/5] libdwfl: expand stack frame interface Omar Sandoval
2019-10-07  9:05 ` [PATCH 1/5] libdwfl: don't bother freeing frames outside of dwfl_thread_getframes Omar Sandoval
2019-10-29 15:55   ` Mark Wielaard
2019-10-29 16:17     ` Omar Sandoval
2019-10-29 16:52       ` Mark Wielaard
2019-10-07  9:05 ` [PATCH 3/5] libdwfl: add interface for attaching to/detaching from threads Omar Sandoval
2019-10-30 12:47   ` Mark Wielaard
2019-10-30 23:49     ` Omar Sandoval
2019-10-31 16:21       ` Mark Wielaard
2019-10-31 17:13         ` Omar Sandoval
2019-10-07  9:05 ` [PATCH 2/5] libdwfl: only use thread->unwound for initial frame Omar Sandoval
2019-10-29 22:20   ` Mark Wielaard
2019-10-07  9:05 ` [PATCH 4/5] libdwfl: cache Dwfl_Module and Dwarf_Frame for Dwfl_Frame Omar Sandoval
2019-10-30 13:04   ` Mark Wielaard [this message]
2019-10-30 23:55     ` Omar Sandoval
2019-10-31 16:29       ` Mark Wielaard
2019-10-07  9:05 ` [PATCH 5/5] libdwfl: add interface for evaluating DWARF expressions in a frame Omar Sandoval
2019-10-30 13:23   ` Mark Wielaard
2019-10-30 23:59     ` Omar Sandoval
2019-10-31 16:40       ` Mark Wielaard

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