From: Bakul Shah <bakul@bitblocks.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] assembly syntax in plan 9
Date: Mon, 16 Jan 2012 08:54:09 -0800 [thread overview]
Message-ID: <72D563DD-2603-424D-9946-569D7AE34A15@bitblocks.com> (raw)
In-Reply-To: <4F144B53.6070906@gmail.com>
On Jan 16, 2012, at 8:07 AM, "Joel C. Salomon" <joelcsalomon@gmail.com> wrote:
> This would make it difficult to implement C99's variable-length
> (actually, run-time-determined--length) arrays. The best compiler-only
> change I can think of would be to define a hidden variable `size_t
> __size_of_all_vlas`, and add code to adjust SP by that amount before &
> after each function call.
Length can be derived from user input, or diff. arrays can be allocated in diff. branches of switch or if stmt. so your trick won't always work.
> Google turns up <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39337>,
> indicating that GCC had issues combining VLAs and -fomit-frame-pointer;
> I don't know how they managed the combination.
Must use a frame pointer in any function that has VLAs and must save it before calling another function from it.
prev parent reply other threads:[~2012-01-16 16:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 12:30 Alexander Kapshuk
2012-01-16 13:08 ` Charles Forsyth
2012-01-16 13:27 ` Alexander Kapshuk
2012-01-16 15:41 ` Bakul Shah
2012-01-16 18:51 ` Comeau At9Fans
2012-01-16 19:03 ` Bakul Shah
2012-01-16 19:39 ` Charles Forsyth
2012-01-17 19:27 ` Comeau At9Fans
[not found] ` <CAOw7k5iYxoVUHYYxf1Dg9ESWwTon_aGFxhNkuyUGbkXwiKO9DA@mail.gmail.c>
2012-01-16 19:49 ` erik quanstrom
2012-01-17 19:29 ` Comeau At9Fans
2012-01-16 20:11 ` Joel C. Salomon
2012-01-16 23:18 ` Bakul Shah
2012-01-17 19:31 ` Comeau At9Fans
2012-01-17 19:21 ` Comeau At9Fans
2012-01-18 17:48 ` Bakul Shah
2012-01-18 18:32 ` Comeau At9Fans
2012-01-16 16:07 ` Joel C. Salomon
2012-01-16 16:27 ` erik quanstrom
2012-01-16 16:40 ` Charles Forsyth
2012-01-16 16:54 ` Bakul Shah [this message]
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