From: Dmitry Antipov <dmantipov@yandex.ru>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: 18410@debbugs.gnu.org
Subject: bug#18410: Use SAFE_ALLOCA etc. to avoid unbounded stack allocation.
Date: Fri, 05 Sep 2014 12:45:27 +0400 [thread overview]
Message-ID: <54097827.1020508@yandex.ru> (raw)
In-Reply-To: <5409536B.5090201@cs.ucla.edu>
On 09/05/2014 10:08 AM, Paul Eggert wrote:
> Attached is a patch to fix the unbounded alloca calls that I found when auditing the Emacs source.
> I'm sending this to bug-gnu-emacs to give Eli a heads-up, as some of the fixes affect Windows code.
> This patch is relative to Emacs trunk bzr 117822.
Code like:
USE_SAFE_ALLOCA; |-
ptrdiff_t count = SPECPDL_INDEX (); |- |
... | inner bind | outer bind
Lisp_Object result = unbind_to (count, Fsome_func ()); |- |
SAFE_FREE (); |-
return result;
looks suboptimal because it calls unbind_to twice. May be we need SAFE_FREE_RETURN,
somewhat similar to RETURN_UNGCPRO? I.e. we should be able to say:
USE_SAFE_ALLOCA;
ptrdiff_t count = SPECPDL_INDEX ();
...
SAFE_FREE_RETURN (Fsome_func ());
Minor note: why specbind can't return previous binding level?
To avoid extra typing, someone can write:
ptrdiff_t count = specbind (Qsome_var, Qnil);
instead of:
ptrdiff_t count = SPECPDL_INDEX ();
specbind (Qsome_var, Qnil);
Dmitry
next prev parent reply other threads:[~2014-09-05 8:45 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-05 6:08 bug#18410: Use SAFE_ALLOCA etc. to avoid unbounded stack allocation Paul Eggert
2014-09-05 8:45 ` Dmitry Antipov [this message]
2014-09-05 15:01 ` Paul Eggert
2014-09-05 15:44 ` Stefan Monnier
2014-09-05 16:04 ` Andreas Schwab
2014-09-05 17:22 ` Stefan Monnier
2014-09-05 8:59 ` Dmitry Antipov
2014-09-05 15:03 ` Paul Eggert
2014-09-07 7:20 ` Paul Eggert
2014-09-07 17:09 ` Eli Zaretskii
2014-09-07 20:33 ` Paul Eggert
2014-09-08 2:22 ` Stefan Monnier
2014-09-08 2:35 ` Eli Zaretskii
2014-09-08 2:43 ` Stefan Monnier
2014-09-08 2:38 ` Paul Eggert
2014-09-08 3:17 ` Demetrios Obenour
2014-09-08 3:19 ` Daniel Colascione
2014-09-08 3:20 ` Demetrios Obenour
2014-09-08 7:26 ` Dmitry Antipov
2014-09-08 2:36 ` Eli Zaretskii
2014-09-08 12:48 ` Stefan Monnier
2014-09-09 13:17 ` Eli Zaretskii
2014-09-09 13:49 ` Stefan Monnier
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