From: Ulf Hermann <ulf.hermann@qt.io>
To: Jan Kratochvil <jan.kratochvil@redhat.com>,
Milian Wolff <mail@milianw.de>
Cc: <elfutils-devel@sourceware.org>, Mark Wielaard <mark@klomp.org>
Subject: Re: frame unwinding patches
Date: Tue, 04 Apr 2017 08:25:00 -0000 [thread overview]
Message-ID: <069f0297-7c48-faf3-694f-dee2919f4edc@qt.io> (raw)
In-Reply-To: <20170404075532.GA11810@host1.jankratochvil.net>
>> - In the example above, the address points into libnvidia-glcore.so and as
>> such not compiled by my colleague but rather provided by NVidia as a binary
>> blob. When you only got a binary blob and have to make do with it, you cannot
>> tell people to "just fix the compiler invocation".
>
> This is their problem they support a vendor who cripples usage of their
> products. There is also Intel and AMD.
Sorry, but I cannot tell everybody with binary-only graphics drivers
that they cannot use perfparser. That's probably the majority of
embedded devices and a large number of desktops.
>> - Some JIT compilers, like QV4, actually embed frame pointers into their
>> dynamic code, but do not go the extra mile for generating DWARF data or
>> asynchronous unwind tables. That is another case where the patches by Ulf
>> excel and make elfutils much more useful.
>
> In such case elfutils could provide some workaround with a new eu-stack option:
> --please-workaround-a-completely-broken-compiler-i-still-have-not-fixed
Frame pointers are the easiest way to include unwinding information into
a binary and they require less work from the compiler than other
methods. With JIT compilers, compile time matters much more than with
ahead of time compilers. Also, adding extra code to the compiler has to
be justified in that case as the compiler is shipped inside the
libQt5Qml binary and loaded into memory whenever you run some QML.
So, I think frame pointers are a perfectly valid option for unwinding
and should be supported.
prev parent reply other threads:[~2017-04-04 8:25 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-15 23:34 Mark Wielaard
2017-02-15 23:34 ` [PATCH 3/3] Add frame pointer unwinding for aarch64 Mark Wielaard
2017-02-15 23:34 ` [PATCH 1/3] Add frame pointer unwinding as fallback on x86_64 Mark Wielaard
2017-02-15 23:34 ` [PATCH 2/3] Add frame pointer unwinding as fallback on arm Mark Wielaard
2017-02-16 9:13 ` frame unwinding patches Ulf Hermann
2017-04-03 9:00 ` Milian Wolff
2017-04-03 9:03 ` Ulf Hermann
2017-04-03 21:14 ` Mark Wielaard
2017-04-07 10:27 ` Mark Wielaard
2017-04-11 10:16 ` Ulf Hermann
2017-04-19 19:48 ` Mark Wielaard
2017-04-20 9:26 ` Ulf Hermann
2017-04-25 12:50 ` Mark Wielaard
2017-04-25 12:54 ` [PATCH 1/5] Revert "Optionally allow unknown symbols in the backtrace tests" Mark Wielaard
2017-04-25 12:50 ` [PATCH 2/5] tests: Add core backtracegen chec and regenerate ppc32 backtrace test files Mark Wielaard
2017-04-25 13:04 ` Ulf Hermann
2017-04-25 12:55 ` [PATCH 3/5] Add frame pointer unwinding as fallback on x86_64 Mark Wielaard
2017-04-25 13:05 ` Ulf Hermann
2017-04-25 12:56 ` [PATCH 1/5] Revert "Optionally allow unknown symbols in the backtrace tests" Ulf Hermann
2017-04-25 12:56 ` [PATCH 4/5] Add i386 frame pointer unwinder Mark Wielaard
2017-04-25 13:38 ` Ulf Hermann
2017-04-25 13:11 ` [PATCH 5/5] Add frame pointer unwinding for aarch64 Mark Wielaard
2017-04-25 21:55 ` Ulf Hermann
2017-04-25 22:13 ` Mark Wielaard
2017-04-25 22:23 ` Ulf Hermann
2017-04-26 15:24 ` Mark Wielaard
2017-04-27 14:02 ` Ulf Hermann
2017-04-27 14:29 ` Mark Wielaard
2017-04-27 14:35 ` Ulf Hermann
2017-04-27 15:09 ` Mark Wielaard
2017-04-27 15:42 ` Ulf Hermann
2017-05-03 8:46 ` Mark Wielaard
2017-04-26 15:20 ` frame unwinding patches Ulf Hermann
2017-04-03 21:23 ` Jan Kratochvil
2017-04-04 7:40 ` Milian Wolff
2017-04-04 7:55 ` Jan Kratochvil
2017-04-04 8:25 ` Ulf Hermann [this message]
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