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Re: Python Front-end to GCC

From Dave Angel <davea@davea.name>
Subject Re: Python Front-end to GCC
Date 2013-10-22 14:04 +0000
References (2 earlier) <5264dbbe$0$30000$c3e8da3$5496439d@news.astraweb.com> <mailman.1308.1382349341.18130.python-list@python.org> <5265bba8$0$29981$c3e8da3$5496439d@news.astraweb.com> <mailman.1345.1382433285.18130.python-list@python.org> <526668e5$0$29981$c3e8da3$5496439d@news.astraweb.com>
Newsgroups comp.lang.python
Message-ID <mailman.1354.1382450725.18130.python-list@python.org> (permalink)

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On 22/10/2013 08:00, Steven D'Aprano wrote:

> On Tue, 22 Oct 2013 10:14:16 +0100, Oscar Benjamin wrote:
>
   <snip>
> Here's an example: responding to a benchmark showing a Haskell compiler 
> generating faster code than a C compiler, somebody re-wrote the C code 
> and got the opposite result:
>
> http://jacquesmattheij.com/when-haskell-is-not-faster-than-c
>
> Again, I can't judge the validity of all of the changes he made, but one 
> stood out like a sore thumb:
>
>     [quote]
>     C does not require you to set static global arrays to ‘0’, so the 
>     for loop in the main function can go...
>
> Wait a minute... Haskell, I'm pretty sure, zeroes memory. C doesn't. So 

Static int variables are in fact zeroed.  However, most C compilers do
it by putting four bytes (or whatever) into the image of the
executable so it has no runtime cost.

<snip>
> But eventually[1] you will need to fix the security
> vulnerability by adding code to zero the memory, exactly as Haskell and 
> other more secure languages already do. So *not* zeroing the memory is
> cheating. It's not something you'd do in real code, not if you care
> about security and correctness.

I agree with most of what you say in the message, but here you go on to
say the C code is unsafely skipping initialization, which is not the
case.

By the way, a C compiler typically handles any initialization of a
static variable the same way.  So if you declare and initialize a static
variable as

int  myvar = 34 * 768;

it'll put the product directly in the executable image, and no runtime
code is generated.

Perhaps you were thinking of an automatic variable, which is not
initialized unless the programmer says so, and is then initialized with
code.

-- 
DaveA

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Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-20 10:56 -0700
  Re: Python Front-end to GCC victorgarcianet@gmail.com - 2013-10-20 15:10 -0700
    Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-22 23:48 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-23 00:25 -0700
        Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 09:42 +0100
        Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-23 13:51 -0700
  Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-20 20:35 -0700
    Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-21 07:46 +0000
      Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-21 10:55 +0100
        Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-21 23:41 +0000
          Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 10:14 +0100
            Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:32 -0700
            Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 12:00 +0000
              Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-22 23:20 +1100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:27 +0000
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 08:43 +1100
              Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 14:04 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 15:22 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:39 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 16:40 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 17:50 +0100
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 09:52 -0700
                Re: Python Front-end to GCC Frank Miles <fpm@u.washington.edu> - 2013-10-22 16:53 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:23 +0000
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 10:35 -0700
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:37 +0000
                Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 18:37 +0100
                Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 18:42 +0100
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:49 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 04:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 04:55 -0700
                Re: Python Front-end to GCC Dan Sommers <dan@tombstonezero.net> - 2013-10-25 12:55 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 15:18 +0100
                Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-25 10:35 -0400
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:26 -0700
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-25 19:06 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 19:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:45 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 11:59 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:09 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 12:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:02 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:18 -0700
                Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-26 14:31 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 15:10 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-27 15:14 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-27 19:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-28 08:44 +0000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-28 02:31 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:36 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:49 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:14 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:11 +1100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 13:29 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:36 +0100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-26 02:42 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:44 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:48 +1100
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:56 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:02 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:11 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:37 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:56 +0100
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-26 13:36 +1100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:15 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:58 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 20:26 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:36 +0000
              Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 15:15 +0100
      Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:14 -0700
      Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-21 16:29 -0400
        Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-21 20:40 -0700
  Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 04:08 -0700
    Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:26 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 14:03 -0700
        Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 16:04 -0700
          Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-21 23:45 -0400
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 21:24 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-22 05:25 +0000
            Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 04:39 +0000
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 08:04 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:09 +0000
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 13:20 -0400
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 11:46 -0400
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 16:52 +0100
            Re: Python Front-end to GCC Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-10-22 09:03 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 10:50 -0700
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:11 -0700
              Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 18:18 +0000
                Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 15:20 -0400
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 19:27 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:38 +0100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 20:00 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:32 +0100
            Re: Python Front-end to GCC Skip Montanaro <skip@pobox.com> - 2013-10-22 13:08 -0500
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:16 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:16 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:22 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:28 -0700
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 18:11 -0400
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 17:28 +1100
              Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 22:47 +0000
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:23 -0400
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:40 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 19:58 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:40 -0400
              Re: Python Front-end to GCC alex23 <wuwei23@gmail.com> - 2013-10-23 11:36 +1000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 21:04 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:06 +0100
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:47 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 13:56 -0400
            Re: Python Front-end to GCC Michael Torrie <torriem@gmail.com> - 2013-10-22 22:05 -0600
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:13 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:25 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:33 -0700
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:38 +0100
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:35 +0100
    Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 08:55 +0000
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:08 -0700
      Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 10:10 +0000
        Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 15:51 +0000
    Re: Python Front-end to GCC Stefan Behnel <stefan_ml@behnel.de> - 2013-10-24 08:47 +0200
  Re: Python Front-end to GCC xDog Walker <thudfoo@gmail.com> - 2013-10-25 14:49 -0700

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