From: Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Maxim Kokryashkin <m.kokryashkin@tarantool.org> Cc: Maksim Kokryashkin <max.kokryashkin@gmail.com>, tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding. Date: Thu, 1 Dec 2022 11:52:18 +0300 [thread overview] Message-ID: <Y4hrQkelVoR+1t1G@root> (raw) In-Reply-To: <1669814478.236264054@f547.i.mail.ru> Hi, thanks for the explanations! LGTM, then. On 30.11.22, Maxim Kokryashkin wrote: > > Hi! > Thanks for the review! > > > > >>Hi, Maksim! > >> > >>Thanks for the patch! > >> > >>LGTM, but I have a bunch of questions to clarify it. > >> > >>On 28.10.22, Maksim Kokryashkin wrote: > >>> Contributed by Edmund Kapusniak. For more info, > >>> see #698 and #757. > >>> > >>> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f) > >>> > >>> To allow compiler generate compact unwind info generation > >>> for Mach-O, fp must point to the saved fp, and the frame > >>> must be specified relative to fp+16. > >> > >>Is there any link to documentation or source code to inspect this > >>behaviour? > >Unfortunately, there are no official docs for that. However, there is > >a community effort to create one here[1]. Also, this header file from > >the Apple’s sources is quite useful. Added both of them to commit > >message for those who will get the masculine urge to dive into this. Meh, not much info about it in the mentioned doc. I suppose that aarch64 ABI requires to save fp and lr by analog with arm arch. See the following comment for arm (unfortunately, there is no such comment for aarch64). https://github.com/gcc-mirror/gcc/blob/master/gcc/config/arm/arm.h#L812 But I'm still struggling to find some relative docs about it. > >> > >>> ELF unwind info has > >>> been updated to also use fp+16 rather than sp+CFRAME_SIZE. > >> <snipped> > >>> Offset to pointer to personality routine specified as @GOT-. rather > >>> than @GOTPCREL. > >> > >>Does it mean that we use incorrect encoded offset (I see encoding for > >>offset is still the same) for our personality routine? > >>If so, maybe the other changes are just refactoring? > >No, that is not correct. Offset has changed, because any > >`func@GOT` expression is translated into offset. > >Moreover, I doubt it is possible to fill in offset to GOT by hand. > >What goes after the pointer to the personality routine > >is LSDA, according to the Apple’s source[2]. @GOTPCREL and @GOT > >are interchangeable most of the time, except for the cases when signed > >32-bit RIP references are not enough for you, which seems to be the case here. So, GOTPCREL allows you to "recalculate" reference to a function to 32-bit value and use it? Do I get the idea correct? > >> > >>> > >>> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX. > >>> > >>> Maxim Kokryashkin: > >>> * added the description for the issue and the test > >>> > >>> Resolves tarantool/tarantool#6096 > >>> Part of tarantool/tarantool#7230 > >>> --- <snipped> > >[1]: https://faultlore.com/blah/compact-unwinding/#unwinding-tables-dwarf-cfi > >[2]: https://opensource.apple.com/source/libunwind/libunwind-35.3/include/mach-o/compact_unwind_encoding.h > >-- > >Best regards, > >Maxim Kokryashkin > > -- Best regards, Sergey Kaplun
next prev parent reply other threads:[~2022-12-01 8:55 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20221028092638.11506-1-max.kokryashkin@gmail.com> [not found] ` <20221028092638.11506-9-max.kokryashkin@gmail.com> 2022-11-24 13:10 ` Sergey Kaplun via Tarantool-patches 2022-11-30 13:21 ` Maxim Kokryashkin via Tarantool-patches 2022-12-01 8:52 ` Sergey Kaplun via Tarantool-patches [this message] 2022-12-01 12:28 ` Sergey Kaplun via Tarantool-patches 2022-12-06 5:58 ` sergos via Tarantool-patches [not found] ` <20221028092638.11506-2-max.kokryashkin@gmail.com> 2022-12-05 16:01 ` [Tarantool-patches] [PATCH luajit v4 1/8] Cleanup and enable external unwinding for more platforms sergos via Tarantool-patches [not found] ` <20221028092638.11506-3-max.kokryashkin@gmail.com> 2022-12-05 16:06 ` [Tarantool-patches] [PATCH luajit v4 2/8] OSX: Fix build by hardcoding external frame unwinding sergos via Tarantool-patches [not found] ` <20221028092638.11506-4-max.kokryashkin@gmail.com> 2022-12-05 16:11 ` [Tarantool-patches] [PATCH luajit v4 3/8] OSX/ARM64: Disable external unwinding for now sergos via Tarantool-patches [not found] ` <20221028092638.11506-5-max.kokryashkin@gmail.com> 2022-11-24 11:37 ` [Tarantool-patches] [PATCH luajit v4 4/8] ARM64: Reorder interpreter stack frame and fix unwinding Sergey Kaplun via Tarantool-patches 2022-11-30 13:04 ` Maxim Kokryashkin via Tarantool-patches 2022-12-05 21:42 ` sergos via Tarantool-patches [not found] ` <20221028092638.11506-6-max.kokryashkin@gmail.com> 2022-11-24 11:41 ` [Tarantool-patches] [PATCH luajit v4 5/8] OSX/ARM64: Disable unwind info Sergey Kaplun via Tarantool-patches 2022-11-30 13:05 ` Maxim Kokryashkin via Tarantool-patches 2022-12-05 21:43 ` sergos via Tarantool-patches [not found] ` <20221028092638.11506-7-max.kokryashkin@gmail.com> 2022-11-24 11:49 ` [Tarantool-patches] [PATCH luajit v4 6/8] BSD: Fix build with BSD grep Sergey Kaplun via Tarantool-patches 2022-11-30 13:05 ` Maxim Kokryashkin via Tarantool-patches 2022-12-05 21:46 ` sergos via Tarantool-patches [not found] ` <20221028092638.11506-8-max.kokryashkin@gmail.com> 2022-11-24 11:56 ` [Tarantool-patches] [PATCH luajit v4 7/8] Fix build with busybox grep Sergey Kaplun via Tarantool-patches 2022-11-30 13:06 ` Maxim Kokryashkin via Tarantool-patches 2022-12-05 21:51 ` sergos via Tarantool-patches
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