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From: Nick Clifton <nickc@redhat.com>
To: Michael Matz <matz@suse.de>
Cc: Ian Lance Taylor <iant@google.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, Pedro Alves <palves@redhat.com>,
	Richard Guenther <richard.guenther@gmail.com>,
	Jakub Jelinek <jakub@redhat.com>,
	sgayou@redhat.com, Tom Tromey <tom@tromey.com>,
	GCC Patches <gcc-patches@gcc.gnu.org>,
	Binutils <binutils@sourceware.org>,
	Jason Merrill <jason@redhat.com>
Subject: Re: [PATCH] Set DEMANGLE_RECURSION_LIMIT to 1536
Date: Mon, 10 Dec 2018 15:12:00 -0000	[thread overview]
Message-ID: <9e739bbc-38a2-c3b1-3b2b-f8de4b755d47@redhat.com> (raw)
In-Reply-To: <alpine.LSU.2.21.1812101442470.5354@wotan.suse.de>

Hi Michael,

> I think this points toward the limit being _much_ too low.

Fair enough - several other people have said this as well.  So
I have proposed an alternative patch instead.  My current suggestion
is to raise the limit to 2048, which allows the libiberty patch to 
pass.  But do you have a feel for how much is a realistic limit ?


> demangler, just looking at the symbol name and demangled result I don't 
> readily see where the depth of recursion really is more than 1024, are 
> there perhaps some recursion_level-- statements skipped?

I do not think so.  Unless there are some long jumps in the demangling code ?
I did a quick scan and did not find any, but I could have missed something.
Plus of course I cannot guarantee that my patch is bug free, although looking
at it again I do not see where I missed a level decrement.  

I think that the demangling code just is really recursive...

Cheers
  Nick

  parent reply	other threads:[~2018-12-10 15:12 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-30  8:38 RFA/RFC: Add stack recursion limit to libiberty's demangler Nick Clifton
2018-11-30  8:42 ` Jakub Jelinek
2018-11-30 10:27   ` Nick Clifton
2018-11-30 13:46     ` Michael Matz
2018-11-30 14:57       ` Ian Lance Taylor
2018-12-02  0:49         ` Cary Coutant
2018-12-03 14:53           ` Nick Clifton
2018-12-03 22:00           ` Joseph Myers
2018-11-30 13:56     ` Ian Lance Taylor
2018-11-30 14:03       ` Jakub Jelinek
2018-11-30 17:41         ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v3] Nick Clifton
2018-11-30 17:49           ` Jakub Jelinek
2018-11-30 18:19           ` Pedro Alves
2018-12-03 10:28           ` Richard Biener
2018-12-03 14:45             ` Nick Clifton
2018-12-03 18:49               ` Ian Lance Taylor via gcc-patches
2018-12-04 14:00                 ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v4] Nick Clifton
2018-12-04 15:02                   ` Pedro Alves
2018-12-04 16:57                     ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v5] Nick Clifton
2018-12-04 17:08                       ` Pedro Alves
2018-12-06 11:12                         ` Nick Clifton
2018-12-06 18:04                           ` Ian Lance Taylor via gcc-patches
2018-12-07 16:17                             ` H.J. Lu
2018-12-07 16:25                               ` [PATCH] Set DEMANGLE_RECURSION_LIMIT to 1536 H.J. Lu
2018-12-10 14:52                                 ` Michael Matz
2018-12-10 15:10                                   ` Jakub Jelinek
2018-12-10 15:34                                     ` Jason Merrill
2018-12-11  0:33                                       ` Jeff Law
2018-12-11  6:58                                         ` Jakub Jelinek
2018-12-11 11:05                                           ` Pedro Alves
2018-12-11 14:26                                             ` Ian Lance Taylor via gcc-patches
2018-12-11 15:07                                               ` Pedro Alves
2018-12-11 10:34                                         ` Pedro Alves
2018-12-10 15:12                                   ` Nick Clifton [this message]
2018-12-10 15:18                                     ` Jakub Jelinek
2018-12-10 15:26                                       ` Nick Clifton
2018-12-10 15:35                                         ` Jakub Jelinek
2018-12-10 18:20                                           ` Ian Lance Taylor via gcc-patches
2018-12-10 18:55                                             ` Jakub Jelinek
2018-12-10 23:47                                               ` Jason Merrill
2018-12-10 15:18                                   ` David Malcolm
2018-12-10 15:31                                     ` Nick Clifton
2018-12-06 16:14                       ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v5] Jason Merrill
2018-12-06 21:22                         ` RFC: libiberty PATCH to disable demangling of ancient mangling schemes Jason Merrill
2018-12-07 10:27                           ` Nick Clifton
2018-12-07 10:40                             ` Jakub Jelinek
2018-12-07 16:11                               ` Pedro Alves
2018-12-07 17:49                                 ` Tom Tromey
2018-12-07 21:00                                   ` Jason Merrill
2018-12-14 22:39                                     ` Jason Merrill
2018-12-16  4:50                                       ` Simon Marchi
2018-12-07 16:28                               ` Nick Clifton
2018-12-07 11:37                           ` Richard Biener
2018-12-07 15:49                             ` Jason Merrill
2018-12-10  1:04                               ` Eric Gallager

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