From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: "Maciej W. Rozycki" <macro@wdc.com>,
Andrew Waterman <andrew@sifive.com>,
Kito Cheng <kito.cheng@gmail.com>,
Andreas Schwab <schwab@linux-m68k.org>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH v3] libgcc: Use `-fasynchronous-unwind-tables' for LIB2_DIVMOD_FUNCS
Date: Wed, 26 Aug 2020 13:33:50 +0200 [thread overview]
Message-ID: <20200826113350.GE2961@tucnak> (raw)
In-Reply-To: <CAFiYyc2-kXt8xksf3JB4kDO_L3izCQ6F9_iKxmR7mcSpLZFRrA@mail.gmail.com>
On Wed, Aug 26, 2020 at 01:08:00PM +0200, Richard Biener via Gcc-patches wrote:
> You only need -fexceptions for that, then you can throw; from a signal handler
> for example. If you want to be able to catch the exception somewhere up
> the call chain all intermediate code needs to be compiled so that unwinding
> from asynchronous events is possible - -fasynchronous-unwind-tables.
>
> So -fasynchronous-unwind-tables is about unwinding. -f[non-call]-exceptions
> is about throw/catch. Clearly libgcc does neither throw nor catch but with
> async events we might need to unwind from inside it.
In C code -f{,non-call-}exceptions is also about whether cleanup attribute
will work or not. But I think in libgcc we don't really use it, especially
not in the division/modulo code, not even indirectly from libc headers like
pthread_cleanup_* macros.
Jakub
next prev parent reply other threads:[~2020-08-26 11:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 18:45 Maciej W. Rozycki
2020-08-25 1:41 ` Kito Cheng
2020-08-25 9:29 ` Kito Cheng
2020-08-25 16:32 ` Maciej W. Rozycki
2020-08-26 3:42 ` Kito Cheng
2020-08-26 11:08 ` Richard Biener
2020-08-26 11:33 ` Jakub Jelinek [this message]
2020-08-28 15:40 ` Maciej W. Rozycki
2020-08-28 17:04 ` Jakub Jelinek
2020-08-31 15:26 ` Maciej W. Rozycki
2020-08-28 15:47 ` Ramana Radhakrishnan
2020-08-31 8:04 ` Richard Biener
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