From: Helmut Eller <eller.helmut@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: gerd.moellmann@gmail.com, emacs-devel@gnu.org
Subject: Re: MPS prstack
Date: Mon, 27 May 2024 14:39:37 +0200 [thread overview]
Message-ID: <87ed9nmnsm.fsf@gmail.com> (raw)
In-Reply-To: <86sey3v5p8.fsf@gnu.org> (Eli Zaretskii's message of "Mon, 27 May 2024 14:45:39 +0300")
On Mon, May 27 2024, Eli Zaretskii wrote:
>> But my question was more whether MPS actually does call scan_prstack at
>> "any moment" or if this is just a theoretical possibility for some
>> possible future version of MPS.
>
> Why is all this order important, can you elaborate? Neither MPS nor
> we can rely on the order in which the generated code does this stuff,
> AFAIU.
It is important because scan_prstack only scans the region
prstack.stack[0..prstack.sp] and because scan_prstack runs (potentially)
concurrent to print_stack_push.
If print_stack_push increments prstack.sp before initializing
prstack.stack[prstack.sp], then scan_prstack may read the old value out
of that slot.
That a compiler will "rewrite"
prstack.stack[prstack.sp] = e;
prstack.sp += 1;
to
prstack.sp += 1;
prstack.stack[prstack.sp - 1] = e;
seems very unlikely the me. But granted, compilers are known to do
unhelpful things in the name of optimization.
next prev parent reply other threads:[~2024-05-27 12:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-20 17:54 MPS prstack Helmut Eller
2024-05-20 18:21 ` Gerd Möllmann
2024-05-20 18:32 ` Helmut Eller
2024-05-21 3:30 ` Gerd Möllmann
2024-05-22 16:27 ` Helmut Eller
2024-05-22 17:55 ` Gerd Möllmann
2024-05-24 14:17 ` Helmut Eller
2024-05-24 14:27 ` Gerd Möllmann
2024-05-25 13:45 ` Gerd Möllmann
2024-05-27 7:27 ` Helmut Eller
2024-05-27 8:43 ` Gerd Möllmann
2024-05-27 9:15 ` Helmut Eller
2024-05-27 9:47 ` Gerd Möllmann
2024-05-27 11:45 ` Eli Zaretskii
2024-05-27 12:39 ` Helmut Eller [this message]
2024-05-27 13:12 ` Eli Zaretskii
2024-05-27 14:15 ` Helmut Eller
2024-05-27 14:37 ` Mattias Engdegård
2024-05-27 14:54 ` Helmut Eller
2024-05-27 14:43 ` Po Lu
2024-05-27 15:08 ` Helmut Eller
2024-05-27 11:34 ` Eli Zaretskii
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