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From: Joe Buck <jbuck@synopsys.COM>
To: jvickers@dial.pipex.com (John Vickers)
Cc: jbuck@synopsys.com, law@cygnus.com, mark@codesourcery.com,
	gcc@gcc.gnu.org, rms@gnu.org
Subject: Re: type based aliasing again
Date: Thu, 30 Sep 1999 18:02:00 -0000	[thread overview]
Message-ID: <199909100000.RAA25523@atrus.synopsys.com> (raw)
Message-ID: <19990930180200.TlK6JhJURpGBa9ZznOVirPfVcsJK5ZY4A_GBC6jitBY@z> (raw)
In-Reply-To: <37D847DE.6CE17D36@dial.pipex.com>

John Vickers writes:

> A lot of the code - proprietary or otherwise - which people expect to
> just "work" with gcc has no active maintainer.  Maybe it has no
> maintainer precisely because this same code has been working fine for
> years.

Yup.

[ Unnecessary shots at Linus deleted ]

> On the warning side, in practice it seems that many offending constructs
> involve creating a single local variable, taking it's address, and
> casting that address to a different pointer type.  If even just that
> usage, within a single basic block, were diagnosed, maybe a useful
> proportion of the problem cases would be caught.

Exactly; post violations I've seen are of that type.  I can't aspire to
the same level of guru-hood as Jeff, Mark, and Craig, but they are perhaps
missing this point: a whole lot of the errors we've seen are of this
extremely simple form, with the entire error appearing in two or three
adjacent lines of code.  We know the exact offsets of each address and
can clearly see that they collide.




  reply	other threads:[~1999-09-30 18:02 UTC|newest]

Thread overview: 408+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-09-08 19:13 Mike Stump
1999-09-08 19:31 ` Joe Buck
1999-09-30 18:02   ` Joe Buck
1999-09-09  7:12 ` Marc Espie
1999-09-09 20:35   ` Jeffrey A Law
1999-09-10 12:29     ` Sudish Joseph
1999-09-30 18:02       ` Sudish Joseph
1999-09-30 18:02     ` Jeffrey A Law
1999-09-30 18:02   ` Marc Espie
1999-09-09 23:25 ` Richard Stallman
1999-09-08 18:11   ` Joe Buck
1999-09-08 18:43     ` Mark Mitchell
1999-09-08 19:25       ` Joe Buck
1999-09-08 19:51         ` David Edelsohn
1999-09-30 18:02           ` David Edelsohn
1999-09-30 18:02         ` Joe Buck
1999-09-08 19:44       ` Joe Buck
1999-09-08 20:26         ` Mark Mitchell
1999-09-08 20:43           ` Joe Buck
1999-09-08 21:45             ` Mark Mitchell
1999-09-08 22:04               ` Joe Buck
1999-09-08 22:25                 ` Mark Mitchell
1999-09-30 18:02                   ` Mark Mitchell
1999-09-09  2:08                 ` Jeffrey A Law
1999-09-09 10:51                   ` Joe Buck
1999-09-09 16:51                     ` John Vickers
1999-09-09 17:04                       ` Joe Buck [this message]
1999-09-09 17:12                         ` John Vickers
1999-09-30 18:02                           ` John Vickers
1999-09-30 18:02                         ` Joe Buck
1999-09-30 18:02                       ` John Vickers
1999-09-15  2:07                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Joe Buck
1999-09-09 23:26                   ` Richard Stallman
1999-09-09 23:38                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Richard Stallman
1999-09-09 23:26                   ` Richard Stallman
1999-09-30 18:02                     ` Richard Stallman
1999-09-30 18:02                   ` Jeffrey A Law
1999-09-09 23:25                 ` Richard Stallman
1999-09-10  0:06                   ` Mark Mitchell
1999-09-10  0:13                     ` Joe Buck
1999-09-30 18:02                       ` Joe Buck
1999-09-11  0:17                     ` Richard Stallman
1999-09-30 18:02                       ` Richard Stallman
1999-09-30 18:02                     ` Mark Mitchell
1999-09-30 18:02                   ` Richard Stallman
1999-09-30 18:02                 ` Joe Buck
1999-09-08 23:20               ` Richard Henderson
1999-09-08 23:41                 ` Mark Mitchell
1999-09-08 23:44                   ` Richard Henderson
1999-09-08 23:51                     ` Mark Mitchell
1999-09-30 18:02                       ` Mark Mitchell
1999-09-09  2:45                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Richard Henderson
1999-09-30 18:02                   ` Mark Mitchell
1999-09-30 18:02                 ` Richard Henderson
1999-09-30 18:02               ` Mark Mitchell
1999-09-30 18:02             ` Joe Buck
1999-09-08 21:33           ` Joe Buck
1999-09-08 21:56             ` Mark Mitchell
1999-09-30 18:02               ` Mark Mitchell
1999-09-09  1:38             ` Martin v. Loewis
1999-09-30 18:02               ` Martin v. Loewis
1999-09-09 23:25             ` Richard Stallman
1999-09-30 18:02               ` Richard Stallman
1999-09-30 18:02             ` Joe Buck
1999-09-09  2:20           ` Jeffrey A Law
1999-09-09  7:58             ` craig
1999-09-09 10:36               ` Joe Buck
1999-09-09 10:55                 ` Mark Mitchell
1999-09-11  0:15                   ` Richard Stallman
1999-09-30 18:02                     ` Richard Stallman
1999-09-30 18:02                   ` Mark Mitchell
1999-09-09 11:51                 ` craig
1999-09-09 12:45                   ` Joe Buck
1999-09-30 18:02                     ` Joe Buck
1999-09-30 18:02                   ` craig
1999-09-30 18:02                 ` Joe Buck
1999-09-30 18:02               ` craig
1999-09-30 18:02             ` Jeffrey A Law
1999-09-09 23:26           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Mark Mitchell
1999-09-30 18:02         ` Joe Buck
1999-09-09 23:25       ` Richard Stallman
1999-09-10  0:03         ` Mark Mitchell
1999-09-10  0:23           ` Joe Buck
1999-09-11  0:17             ` Richard Stallman
1999-09-30 18:02               ` Richard Stallman
1999-09-30 18:02             ` Joe Buck
1999-09-11  0:17           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Mark Mitchell
1999-09-10 14:29         ` Marc Lehmann
1999-09-30 18:02           ` Marc Lehmann
1999-09-15  2:05         ` Jeffrey A Law
1999-09-15  7:55           ` Nick Ing-Simmons
1999-09-30 18:02             ` Nick Ing-Simmons
1999-09-15 23:14           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Jeffrey A Law
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` Mark Mitchell
1999-09-08 20:44     ` Joe Buck
1999-09-30 18:02       ` Joe Buck
1999-09-14  3:04     ` Alexandre Oliva
1999-09-14  5:34       ` Bernd Schmidt
1999-09-14  5:45         ` Alexandre Oliva
1999-09-14  5:52           ` Bernd Schmidt
1999-09-30 18:02             ` Bernd Schmidt
1999-09-21  1:16           ` Rask Ingemann Lambertsen
1999-09-21  2:02             ` Jamie Lokier
1999-09-30 18:02               ` Jamie Lokier
1999-09-30 18:02             ` Rask Ingemann Lambertsen
1999-09-30 18:02           ` Alexandre Oliva
1999-09-14  9:31         ` Andi Kleen
1999-09-30 18:02           ` Andi Kleen
1999-09-30 18:02         ` Bernd Schmidt
1999-09-14 22:22       ` Richard Stallman
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` Alexandre Oliva
1999-09-30 18:02     ` Joe Buck
1999-09-10  0:11   ` Joe Buck
1999-09-10  8:43     ` craig
1999-09-10 18:25       ` Jonathan Larmour
1999-09-11  3:50         ` craig
1999-09-30 18:02           ` craig
1999-09-30 18:02         ` Jonathan Larmour
1999-09-11  0:15       ` Richard Stallman
1999-09-11  3:51         ` craig
1999-09-12  0:51           ` Richard Stallman
1999-09-12  8:54             ` craig
1999-09-13  0:47               ` Richard Stallman
1999-09-30 18:02                 ` Richard Stallman
1999-09-30 18:02               ` craig
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` craig
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` craig
1999-09-11  0:14     ` Richard Stallman
1999-09-11 15:20       ` Mark Mitchell
1999-09-11 18:04         ` David Edelsohn
1999-09-11 18:20           ` Mark Mitchell
1999-09-11 23:40             ` Sudish Joseph
1999-09-30 18:02               ` Sudish Joseph
1999-09-12  8:16             ` Robert Lipe
1999-09-30 18:02               ` Robert Lipe
1999-09-30 18:02             ` Mark Mitchell
1999-09-13  0:47           ` Richard Stallman
1999-09-15  2:06             ` Jeffrey A Law
1999-09-15  8:02               ` Nick Ing-Simmons
1999-09-15  9:20                 ` Jeffrey A Law
1999-09-15  9:31                   ` David Edelsohn
1999-09-15 10:02                     ` craig
1999-09-16 23:13                       ` Richard Stallman
1999-09-17  1:51                         ` craig
1999-09-17 22:16                           ` Richard Stallman
1999-09-30 18:02                             ` Richard Stallman
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Richard Stallman
1999-09-30 18:02                       ` craig
1999-09-30 18:02                     ` David Edelsohn
1999-09-15  9:56                   ` Nick Ing-Simmons
1999-09-15 10:08                     ` craig
1999-09-15 10:48                       ` Nick Ing-Simmons
1999-09-15 14:32                         ` craig
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Nick Ing-Simmons
1999-09-16 10:54                       ` Andi Kleen
1999-09-16 12:08                         ` Joern Rennecke
1999-09-16 12:18                           ` Mark Mitchell
1999-09-17  7:07                             ` __typealias qualifier (was Re: type based aliasing again) patl
1999-09-17  8:32                               ` Mark Mitchell
1999-09-30 18:02                                 ` Mark Mitchell
1999-09-30 18:02                               ` Patrick J. LoPresti
1999-09-30 18:02                             ` type based aliasing again Mark Mitchell
1999-09-30 18:02                           ` Joern Rennecke
1999-09-16 14:29                         ` craig
1999-09-16 22:19                           ` Andi Kleen
1999-09-30 18:02                             ` Andi Kleen
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Andi Kleen
1999-09-16 23:13                       ` Richard Stallman
1999-09-30 18:02                         ` Richard Stallman
1999-09-30 18:02                       ` craig
1999-09-30 18:02                     ` Nick Ing-Simmons
1999-09-30 18:02                   ` Jeffrey A Law
1999-09-30 18:02                 ` Nick Ing-Simmons
1999-09-15 23:14               ` Richard Stallman
1999-09-30 18:02                 ` Richard Stallman
1999-09-30 18:02               ` Jeffrey A Law
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` David Edelsohn
1999-09-12  9:45         ` Jonathan Larmour
1999-09-30 18:02           ` Jonathan Larmour
1999-09-13  0:47         ` Richard Stallman
1999-09-30 18:02           ` Richard Stallman
1999-09-13  4:05         ` Richard Earnshaw
1999-09-15  2:05           ` Jeffrey A Law
1999-09-30 18:02             ` Jeffrey A Law
1999-09-30 18:02           ` Richard Earnshaw
1999-09-30 18:02         ` Mark Mitchell
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Joe Buck
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Mike Stump
1999-09-09 14:26 Mike Stump
1999-09-09 14:38 ` Mark Mitchell
1999-09-11  0:16   ` Richard Stallman
1999-09-15  2:07     ` Jeffrey A Law
1999-09-30 18:02       ` Jeffrey A Law
1999-09-30 18:02     ` Richard Stallman
1999-09-30 18:02   ` Mark Mitchell
1999-09-30 18:02 ` Mike Stump
1999-09-09 15:40 Claus Fischer
1999-09-09 15:57 ` David Starner
1999-09-09 16:24   ` Claus Fischer
1999-09-09 16:55     ` Joe Buck
1999-09-09 17:31       ` Claus Fischer
1999-09-30 18:02         ` Claus Fischer
1999-09-30 18:02       ` Joe Buck
1999-09-10  8:42     ` craig
1999-09-30 18:02       ` craig
1999-09-30 18:02     ` Claus Fischer
1999-09-30 18:02   ` David Starner
1999-09-09 16:37 ` Jeffrey A Law
1999-09-09 17:15   ` Claus Fischer
1999-09-30 18:02     ` Claus Fischer
1999-09-30 18:02   ` Jeffrey A Law
1999-09-30 18:02 ` Claus Fischer
1999-09-09 21:54 Alex Rosenberg
1999-09-30 18:02 ` Alex Rosenberg
1999-09-10  8:43 craig
1999-09-12  0:49 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` craig
1999-09-11 18:21 Phil Edwards
1999-09-30 18:02 ` Phil Edwards
1999-09-11 21:48 N8TM
1999-09-30 18:02 ` N8TM
     [not found] <9377.936981585@upchuck.cygnus.com>
1999-09-12  0:52 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-12 11:20 Josh Stern
1999-09-30 18:02 ` Josh Stern
1999-09-13 10:55 R. Kelley Cook
1999-09-13 13:22 ` craig
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` R. Kelley Cook
1999-09-13 16:34 Mike Stump
1999-09-14 22:20 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Mike Stump
1999-09-13 21:45 N8TM
1999-09-14  4:01 ` Marc Espie
1999-09-14  9:56   ` David Edelsohn
1999-09-14 10:10     ` Richard Earnshaw
1999-09-14 10:31       ` Nick Ing-Simmons
1999-09-14 10:52         ` David Edelsohn
1999-09-14 11:11           ` craig
1999-09-14 14:44             ` David Edelsohn
1999-09-30 18:02               ` David Edelsohn
1999-09-14 15:06             ` David Edelsohn
1999-09-14 17:35               ` Marc Lehmann
1999-09-30 18:02                 ` Marc Lehmann
1999-09-14 23:41               ` craig
1999-09-15  8:28                 ` Marc Lehmann
1999-09-30 18:02                   ` Marc Lehmann
1999-09-15  9:19                 ` David Edelsohn
1999-09-15  9:59                   ` Nick Ing-Simmons
1999-09-15 15:33                     ` David Edelsohn
1999-09-30 18:02                       ` David Edelsohn
1999-09-30 18:02                     ` Nick Ing-Simmons
1999-09-15 10:01                   ` craig
1999-09-30 18:02                     ` craig
1999-09-30 18:02                   ` David Edelsohn
1999-09-30 18:02                 ` craig
1999-09-30 18:02               ` David Edelsohn
1999-09-30 18:02             ` craig
1999-09-14 11:58           ` Gerald Pfeifer
1999-09-30 18:02             ` Gerald Pfeifer
1999-09-30 18:02           ` David Edelsohn
1999-09-14 11:01         ` craig
1999-09-14 11:14           ` craig
1999-09-30 18:02             ` craig
1999-09-14 11:39           ` Mark Mitchell
1999-09-14 14:48             ` Toon Moene
1999-09-14 15:00               ` David Edelsohn
1999-09-14 16:01                 ` Toon Moene
1999-09-14 16:15                   ` David Edelsohn
1999-09-14 16:43                     ` Mark Mitchell
1999-09-30 18:02                       ` Mark Mitchell
1999-09-14 17:39                     ` Marc Lehmann
1999-09-30 18:02                       ` Marc Lehmann
1999-09-30 18:02                     ` David Edelsohn
1999-09-14 16:19                   ` dvv
1999-09-14 17:38                     ` Michael Meissner
1999-09-30 18:02                       ` Michael Meissner
1999-09-30 18:02                     ` Dima Volodin
1999-09-30 18:02                   ` Toon Moene
1999-09-30 18:02                 ` David Edelsohn
1999-09-14 15:08               ` Mark Mitchell
1999-09-30 18:02                 ` Mark Mitchell
1999-09-30 18:02               ` Toon Moene
1999-09-30 18:02             ` Mark Mitchell
1999-09-30 18:02           ` craig
1999-09-14 23:46         ` Geoff Keating
1999-09-15  7:47           ` Nick Ing-Simmons
1999-09-30 18:02             ` Nick Ing-Simmons
1999-09-30 18:02           ` Geoff Keating
1999-09-30 18:02         ` Nick Ing-Simmons
1999-09-30 18:02       ` Richard Earnshaw
1999-09-14 17:22     ` Marc Lehmann
1999-09-30 18:02       ` Marc Lehmann
1999-09-30 18:02     ` David Edelsohn
1999-09-14 17:23   ` Marc Lehmann
1999-09-15  1:59     ` Marc Espie
1999-09-15  8:28       ` Marc Lehmann
1999-09-30 18:02         ` Marc Lehmann
1999-09-30 18:02       ` Marc Espie
1999-09-30 18:02     ` Marc Lehmann
1999-09-15  2:01   ` Jeffrey A Law
1999-09-30 18:02     ` Jeffrey A Law
1999-09-30 18:02   ` Marc Espie
1999-09-30 18:02 ` N8TM
1999-09-14  6:46 Marcel Cox
1999-09-14  6:50 ` Bernd Schmidt
1999-09-14  7:14   ` Marcel Cox
1999-09-14  8:45     ` Jamie Lokier
1999-09-30 18:02       ` Jamie Lokier
1999-09-30 18:02     ` Marcel Cox
1999-09-30 18:02   ` Bernd Schmidt
1999-09-30 18:02 ` Marcel Cox
1999-09-15  7:02 David Ronis
1999-09-30 18:02 ` David Ronis
1999-09-15  8:27 Kaveh R. Ghazi
1999-09-15  8:57 ` Nathan Sidwell
1999-09-30 18:02   ` Nathan Sidwell
1999-09-30 18:02 ` Kaveh R. Ghazi
1999-09-15 11:42 Michael J. Bedy
1999-09-15 14:32 ` craig
1999-09-16 23:14   ` Richard Stallman
1999-09-30 18:02     ` Richard Stallman
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` Michael J. Bedy
1999-09-15 21:47 Florin Mateoc
1999-09-16  2:18 ` craig
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` Florin Mateoc
     [not found] <Pine.SO4.4.05.9909160153420.23533-100000@tamarack.cs.mtu.edu>
1999-09-16  2:19 ` craig
1999-09-30 18:02   ` craig
1999-09-16  6:12 Artem Hodyush
1999-09-16 23:15 ` Richard Stallman
1999-09-16 23:38   ` Gabriel Dos_Reis
1999-09-17 22:16     ` Richard Stallman
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Gabriel Dos_Reis
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Artem Hodyush
     [not found] <199909161750.LAA12073@basho.fc.hp.com>
1999-09-16 14:29 ` craig
1999-09-20 15:17   ` John W. Stevens
1999-09-30 18:02     ` John W. Stevens
1999-09-30 18:02   ` craig
1999-09-17  9:02 Harvey J. Stein
1999-09-30 18:02 ` Harvey J. Stein
1999-09-18  2:51 Ross Morgan-Linial
     [not found] ` <19990918151905.F1650@cerebro.laendle>
1999-09-18 22:18   ` Ross Morgan-Linial
1999-09-30 18:02     ` Ross Morgan-Linial
1999-09-30 18:02 ` Ross Morgan-Linial
1999-09-18  3:25 Artem Hodyush
1999-09-18 11:29 ` Russ Allbery
1999-09-20  5:54   ` Joern Rennecke
1999-09-30 18:02     ` Joern Rennecke
1999-09-30 18:02   ` Russ Allbery
1999-09-19 13:54 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-21  8:50 ` Harvey J. Stein
1999-09-30 18:02   ` Harvey J. Stein
1999-09-30 18:02 ` Artem Hodyush
1999-09-18  7:30 Stephen L Moshier
1999-09-30 18:02 ` Stephen L Moshier
1999-09-18  8:33 N8TM
1999-09-30 18:02 ` N8TM
1999-09-21  8:48 Harvey J. Stein
1999-09-22 12:15 ` Richard Stallman
1999-09-22 13:08   ` Harvey J. Stein
1999-09-24 23:37     ` Richard Stallman
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Harvey J. Stein
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Harvey J. Stein
     [not found] <19990921182843.25292.qmail@deer>
1999-09-21 15:47 ` John W. Stevens
1999-09-21 16:15   ` craig
1999-09-21 20:37     ` David Edelsohn
1999-09-30 18:02       ` David Edelsohn
1999-09-23  9:06     ` John W. Stevens
1999-09-23 11:06       ` craig
1999-09-30 18:02         ` craig
1999-09-30 18:02       ` John W. Stevens
1999-09-30 18:02     ` craig
1999-09-27  6:56   ` Rask Ingemann Lambertsen
1999-09-27  8:32     ` Joe Buck
1999-09-30 18:02       ` Joe Buck
1999-09-30 18:02     ` Rask Ingemann Lambertsen
1999-09-30 18:02   ` John W. Stevens

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