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Groups > comp.lang.forth > #52627
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: Average swaps per word? |
| Date | 2016-11-14 17:42 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2016Nov14.184256@mips.complang.tuwien.ac.at> (permalink) |
| References | (1 earlier) <2016Nov12.132348@mips.complang.tuwien.ac.at> <o07bak$ru0$1@cherry.spenarnc.xs4all.nl> <2016Nov13.155518@mips.complang.tuwien.ac.at> <o0af90$5sf$1@cherry.spenarnc.xs4all.nl> <871syff9mv.fsf@nightsong.com> |
Paul Rubin <no.email@nospam.invalid> writes:
>albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) writes:
>>>and gcc therefore "optimized" the memset() away. And
>>>while the following read from that memory (due to a buffer overflow)
>> They should have checked what happens while optimising. Failing that
>> they shouldn't have optimised.
>
>The right way to do that in C is with a volatile cast.
Is it? Other people tell me it's memset_s. Looking at the C11
standard for memset_s, I did not see anything that would keep a
sufficiently adverserial compiler writer from optimizing it away. It
says:
|Unlike memset, any call to the memset_s function shall be evaluated
|strictly according to the rules of the abstract machine as described
|in (5.1.2.3). That is, any call to the memset_s function shall assume
|that the memory indicated by s and n may be accessible in the future
|and thus must contain the values indicated by c.
Now, everything else (including memset()) in the standard also is
evaluated according to the rules of the abstract machine, and the
"optimization" comes in afterwards, applies the as-if rule, and poof,
memset() is gone, and so is memset_s(). From what I read, "volatile"
is not specified very clearly, so it probably has this problem and
more.
- anton
--
M. Anton Ertl http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
New standard: http://www.forth200x.org/forth200x.html
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Average swaps per word? trans <transfire@gmail.com> - 2016-11-08 22:03 -0800
Re: Average swaps per word? "Elizabeth D. Rather" <erather@forth.com> - 2016-11-08 20:20 -1000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-09 08:16 +0000
Re: Average swaps per word? Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-09 03:34 -0500
Re: Average swaps per word? trans <transfire@gmail.com> - 2016-11-09 02:53 -0800
Re: Average swaps per word? rickman <gnuarm@gmail.com> - 2016-11-09 11:50 -0500
Re: Average swaps per word? stephen@mpeforth.com (Stephen Pelc) - 2016-11-09 18:37 +0000
Re: Average swaps per word? Harold <hzrabbie@gmail.com> - 2016-11-10 16:28 -0800
Re: Average swaps per word? stephen@mpeforth.com (Stephen Pelc) - 2016-11-11 17:51 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-12 12:23 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-12 16:09 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-13 14:55 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-13 20:34 +0100
Re: Average swaps per word? Paul Rubin <no.email@nospam.invalid> - 2016-11-13 11:43 -0800
Re: Average swaps per word? hughaguilar96@gmail.com - 2016-11-13 16:58 -0800
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-14 16:41 +0100
Re: Average swaps per word? hughaguilar96@gmail.com - 2016-11-14 16:38 -0800
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-14 17:42 +0000
Re: Average swaps per word? Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-14 16:39 -0500
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 12:40 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-17 14:10 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-18 15:14 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-20 18:16 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-22 10:29 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-22 15:54 +0100
Re: Average swaps per word? James Kuyper <jameskuyper@verizon.net> - 2016-11-22 11:50 -0500
Re: Average swaps per word? raltbos@xs4all.nl (Richard Bos) - 2016-11-24 17:27 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-15 03:55 -0600
Re: Average swaps per word? Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-15 17:49 -0500
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-16 02:59 -0600
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 13:07 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-16 22:57 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-17 03:12 -0600
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-17 12:32 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-18 15:02 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 13:23 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-17 08:54 -0600
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-18 15:54 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-18 12:37 -0600
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-14 17:32 +0000
Re: Average swaps per word? Mark Wills <markwills1970@gmail.com> - 2016-11-15 02:09 -0800
Re: Average swaps per word? jim <anon@example.com> - 2016-11-15 10:44 +0000
Re: Average swaps per word? Mark Wills <markwills1970@gmail.com> - 2016-11-15 03:12 -0800
Re: Average swaps per word? Alex <alex@rivadpm.com> - 2016-11-15 13:01 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 12:51 +0000
Re: Average swaps per word? Alex <alex@rivadpm.com> - 2016-11-17 14:02 +0000
Re: Average swaps per word? Alex <alex@rivadpm.com> - 2016-11-17 14:06 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-18 15:26 +0000
Re: Average swaps per word? Alex <alex@rivadpm.com> - 2016-11-18 18:33 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-19 03:32 -0600
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-17 14:29 +0100
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-15 13:51 +0100
Re: Average swaps per word? jim <anon@example.com> - 2016-11-15 13:01 +0000
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 12:46 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-17 14:16 +0100
Re: Average swaps per word? Harold <hzrabbie@gmail.com> - 2016-11-13 11:08 -0800
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-14 17:08 +0000
Re: Average swaps per word? Mark Wills <markwills1970@gmail.com> - 2016-11-15 02:04 -0800
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-15 14:04 +0100
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-15 14:05 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-17 12:58 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-17 15:16 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-18 15:41 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-20 18:12 +0100
Re: Average swaps per word? minforth@arcor.de - 2016-11-09 03:15 -0800
Re: Average swaps per word? trans <transfire@gmail.com> - 2016-11-09 11:22 -0800
Re: Average swaps per word? "HAA" <someone@microsoft.com> - 2016-11-10 12:20 +1100
Re: Average swaps per word? "Elizabeth D. Rather" <erather@forth.com> - 2016-11-09 21:04 -1000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-10 03:45 -0600
Re: Average swaps per word? rickman <gnuarm@gmail.com> - 2016-11-10 11:52 -0500
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-10 11:42 -0600
Re: Average swaps per word? rickman <gnuarm@gmail.com> - 2016-11-10 13:34 -0500
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-10 12:54 -0600
Re: Average swaps per word? rickman <gnuarm@gmail.com> - 2016-11-10 16:33 -0500
Re: Average swaps per word? "Elizabeth D. Rather" <erather@forth.com> - 2016-11-10 15:56 -1000
Re: Average swaps per word? rickman <gnuarm@gmail.com> - 2016-11-10 21:30 -0500
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-11 03:04 -0600
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-12 13:25 +0000
Re: Average swaps per word? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-11-14 03:34 -0600
Re: Average swaps per word? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-11-11 10:41 +0000
Re: Average swaps per word? hughaguilar96@gmail.com - 2016-11-11 16:45 -0800
Re: Average swaps per word? jim <anon@example.com> - 2016-11-10 11:17 +0000
Re: Average swaps per word? Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-11-10 04:34 -0800
Re: Average swaps per word? jim <anon@example.com> - 2016-11-10 12:44 +0000
Re: Average swaps per word? Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-11-10 07:27 -0800
Re: Average swaps per word? Ron Aaron <rambamist@gmail.com> - 2016-11-10 18:26 +0200
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-10 16:05 +0000
Re: Average swaps per word? stephen@mpeforth.com (Stephen Pelc) - 2016-11-10 14:55 +0000
Re: Average swaps per word? "HAA" <someone@microsoft.com> - 2016-11-12 11:36 +1100
Re: Average swaps per word? hughaguilar96@gmail.com - 2016-11-11 16:56 -0800
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-12 16:14 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-12 12:14 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-12 16:16 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-13 14:51 +0000
Re: Average swaps per word? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-13 20:41 +0100
Re: Average swaps per word? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-10 14:42 +0000
Re: Average swaps per word? hughaguilar96@gmail.com - 2016-11-11 15:54 -0800
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