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Groups > comp.lang.forth > #56588
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: LLVM and Forth |
| Date | 2017-04-02 14:41 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2017Apr2.164151@mips.complang.tuwien.ac.at> (permalink) |
| References | <21153661-abf5-4958-82c7-e3c442b45cb9@googlegroups.com> <obogce$er6$1@dont-email.me> <ac4976d7-955a-45e3-9cdd-e339e15acbc2@googlegroups.com> <ZqGdnRes4qCBI33FnZ2dnUU7-VednZ2d@supernews.com> <065e774c-c5fb-4e68-9489-00b5357142d6@googlegroups.com> |
krishna.myneni@ccreweb.org writes:
>On Sunday, April 2, 2017 at 4:02:26 AM UTC-5, Andrew Haley wrote:
>> Optimizing without specific
>> language semantics is somewhere between hard and impossible.
Not in the least. On the contrary, it's harder to "optimize" using
nasal demon semantics, and that's why such "optimizations" are a
relatively recent development.
You can translate the source code to machine code according to the
semantics of the programming language, and then optimize the machine
code. In practice, they used to translate to an intermediate
representation (IR) with machine-level operations, then optimize that,
and then generate code from that.
The newer developments are that they added stuff such as "undefined",
assertions about, e.g., the possible values of things (derived from
nasal demon C semantics), and operations with language-specific nasal
demons to the IR. One could try to avoid all these cliffs, and just
use the machine-level operations (if they are still there), but I
would not bet that every optimization pass (there are several hundred
in LLVM and GCC) actually observes the machine-level semantics rather
than taking liberties based on C semantics.
>The fundamental question appears to be independent of LLVM:
>
>If one were to write a Forth to C translator, how likely is it that the tra=
>nslator would result in C code which is considered undefined in the new C s=
>tandard, i.e. how problematic would "nasal demons" be in the translated cod=
>e?
For a straightforward translation, the likelyhood of undefined
behaviour from many Forth programs is 100%; maybe you are lucky, and
the C compiler still generates the code you intended, maybe not; in
the next compiler version it may be different.
You could go for a more roundabout translation, and with lots of
perseverance and some luck get a translation without undefined
behaviour, but it would be slow and interfacing with the rest of the
world would probably be a problem.
But that's a nasal-demon-C-specific problem. The LLVM people could
have chosen to just have a machine-level IR without any nasal demon
nonsense, and then LLVM would not have had this problem. So the
problem is not really independent of LLVM.
- 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
EuroForth 2016: http://www.euroforth.org/ef16/
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LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 06:36 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-01 14:57 +0000
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 11:55 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-02 15:24 +0000
Re: LLVM and Forth rickman <gnuarm@gmail.com> - 2017-04-01 11:21 -0400
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 11:57 -0700
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-02 04:02 -0500
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-02 06:35 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-02 14:41 +0000
Re: LLVM and Forth minforth@arcor.de - 2017-04-03 01:09 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-03 05:32 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 13:52 +0000
Re: LLVM and Forth minforth@arcor.de - 2017-04-03 07:59 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 16:08 +0000
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 12:22 -0500
Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-03 20:10 -0700
Re: LLVM and Forth minforth@arcor.de - 2017-04-03 22:19 -0700
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 16:12 +0200
Re: LLVM and Forth Walter Banks <walter@bytecraft.com> - 2017-04-05 17:27 -0400
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 14:29 +0000
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 03:17 -0500
Re: LLVM and Forth minforth@arcor.de - 2017-04-03 05:04 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 12:55 +0000
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 10:08 -0500
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 17:05 +0000
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-04 11:29 -0500
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 19:11 +0200
Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-04 21:29 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-05 15:01 +0000
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-05 18:42 +0100
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 04:01 -0500
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 18:48 +0000
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-06 18:42 -0700
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-07 04:02 -0500
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 21:18 -0700
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-08 22:43 +0000
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 20:54 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-09 14:53 +0000
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 00:38 +0000
Re: LLVM and Forth James Kuyper <jameskuyper@verizon.net> - 2017-04-09 22:46 -0400
Re: LLVM and Forth Robert Wessel <robertwessel2@yahoo.com> - 2017-04-09 22:27 -0500
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 12:36 +0000
Re: LLVM and Forth Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-10 14:09 +0100
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 13:07 +0000
Re: LLVM and Forth Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-10 16:18 +0100
Re: LLVM and Forth "James R. Kuyper" <jameskuyper@verizon.net> - 2017-04-10 11:51 -0400
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-12 21:32 +0000
Re: LLVM and Forth "James R. Kuyper" <jameskuyper@verizon.net> - 2017-04-12 18:29 -0400
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-12 15:29 -0700
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-13 02:55 +0200
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-10 18:38 -0700
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-10 11:54 -0500
Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-10 10:17 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 17:02 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 10:03 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 03:25 -0700
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-04 11:24 +0000
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 04:55 -0700
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-04 12:28 +0000
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-04 16:16 +0000
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 15:38 +0200
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 16:06 +0200
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 17:57 -0700
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-05 00:44 -0400
Re: LLVM and Forth minforth@arcor.de - 2017-04-05 00:00 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 08:47 -0700
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-05 11:04 -0500
Re: LLVM and Forth john <anon@example.com> - 2017-04-05 18:04 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-05 13:04 -0700
Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-05 18:20 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 20:14 -0700
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 12:33 +0000
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 10:49 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 18:55 +0100
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 20:41 +0000
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 21:47 +0100
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 21:56 +0100
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 23:59 -0400
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-06 17:10 -0700
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-07 03:33 -0400
Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-08 22:48 +0000
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-09 15:06 -0400
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 22:45 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-09 14:27 +0000
Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-09 21:26 -0700
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-09 13:35 -0400
Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-09 14:07 -0700
Re: LLVM and Forth minforth@arcor.de - 2017-04-05 12:16 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 20:27 -0700
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 05:24 -0400
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 03:26 -0700
Re: LLVM and Forth minforth@arcor.de - 2017-04-06 04:05 -0700
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 06:50 -0500
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 05:23 -0400
Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 04:44 -0500
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 10:57 +0100
Re: LLVM and Forth peter.m.falth@gmail.com - 2017-04-05 05:29 -0700
Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-14 02:04 +0000
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-15 14:03 +0200
Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-16 00:44 +0000
Re: LLVM and Forth alex@rivadpm.com - 2017-04-16 05:53 -0700
Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-16 15:43 +0000
Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-16 22:27 +0000
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-18 02:45 +0200
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-18 18:26 +0100
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-20 19:51 +0200
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 19:08 +0100
Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-20 20:42 +0200
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 20:29 +0100
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 20:48 +0100
Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-21 11:49 +0000
Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-03 20:39 -0400
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-02 21:15 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-02 15:18 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 13:07 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 09:45 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 22:52 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 15:25 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 09:35 +0100
Re: LLVM and Forth antispam@math.uni.wroc.pl - 2017-04-06 01:36 +0000
Re: LLVM and Forth minforth@arcor.de - 2017-04-05 22:00 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 09:52 +0100
Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-06 20:15 -0700
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-03 05:20 -0700
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 17:11 +0100
Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 17:43 +0100
Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 10:53 -0700
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