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Groups > comp.sys.raspberry-pi > #25460

Re: AI and decompilation?

From The Natural Philosopher <tnp@invalid.invalid>
Newsgroups alt.folklore.computers, comp.sys.raspberry-pi
Subject Re: AI and decompilation?
Date 2021-01-05 10:28 +0000
Organization A little, after lunch
Message-ID <rt1f0b$d1f$1@dont-email.me> (permalink)
References <rsusgg$f24$1@dont-email.me> <51f6vf56b3eeacskirm9b54sr7kuf8s1pl@4ax.com> <rsvi0n$epp$7@dont-email.me> <zBIIH.63573$1X1.11761@fx05.iad>

Cross-posted to 2 groups.

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On 04/01/2021 17:52, Scott Lurndal wrote:
> Martin Gregorie <martin@mydomain.invalid> writes:
>> On Mon, 04 Jan 2021 11:05:55 -0500, Dennis Lee Bieber wrote:
>>
>>> On Mon, 4 Jan 2021 11:00:29 +0000, gareth evans <headstone255@yahoo.com>
>>> declaimed the following:
>>>
>>>> Thinking back to my first job, nearly 50 years ago now,
>>>> when I had to dis-assemble DEC's paper tape BASIC interpreter in order
>>>> to enhance it, I guess that dis-assemblers and decompilers must now be
>>>> ten-a-penny,
>>>> especially for programs running under Windows where the structure of
>>>> Windows programs is well-known with an assumption that C was the source
>>>> language?
>>>>
>>> 	Actually, I think the use of disassemblers et al has fallen away.
>>> Modern processors have so many peephole optimizations and out-of-order
>>> execution streams that converting an executable back to assembly source
>>> is almost meaningless -- and getting back to a high-level language is
>>> near impossible. One would have to be an expert at the assembly for a
>>> processor to have any chance of understanding the result.
>>
>> The retro-computing guys - those who are fans of the MC6800 and MC6809
>> microprocessors anyway, anyway, seem to be getting a rather good semi-
>> interactive disassembler up and running.
> 
> Security experts have several very powerful disassemblers and decompilers
> they use for Intel/AMD/ARM processors.
> 
> https://en.wikibooks.org/wiki/X86_Disassembly/Disassemblers_and_Decompilers
> 
Yes. I am certain that certain compilers and certain languages leave a 
fingerprint, Always THAT resister, used to do THAT job, always that 
particular sequence of assembly to mimic that high level construct.
I cut my teeth on microprocessor assembly. The C. Some things that are 
neat in assembler are ugly as sin in C. Take a call table. In assembler, 
  you set up a range of memory whose contents contain the addresses of 
subroutines. You load the accumulator with a number, left shift it once, 
add it to the content of a register set to point to the base of that 
memory block,  and use that register as pointing to an address whose 
contents are the address you want to 'call' Simple, efficient and 
provided you ensure nothing out of bounds is in the accumulator, bomb proof.

Now try that in C, you need an array of pointers to functions, and a 
simple check on the index you engage, followed by a declaration to call 
the function whose address is in the array of pointers to functions. I 
never ever managed to get an 8 bit compiler to actually do that. People 
just don't call the contents of an array of pointers to functions.

Its easier by far to set up a switch statement, which takes care of out 
of bounds defaults, and ends up producing a chain of if..else if.. else 
conditional calls to hardwired functions.

That's how you write it, because its pretty much as fast on a pipelined 
processor, RAM is cheap and comprehensibility beats programming elegance 
hands down in the real world.

I've examined a lot of compiled machine code and its pretty easy to tell 
what language it is, and what roughly it was written as. Stack based 
variables is a bit of a give away pointing to C or a similar langauge. 
highly optimised compilers of course automatically obfuscate things, but 
that's the fun isn't it?

I gave up writing assembler for *86 CPUs when the Gnu compiler was 
patently doing a better job than I would in assembler, and the ability 
to write something long winded and easy to understand and have the 
compiler completely rearrange it and turn it into three lines of 
incomprehensible assembler, was to be respected.

I think it is up to a limited point entirely possible to make an AI that 
could replace  machine code with editable and compilable  source code.
But there will always be the Problem Of Induction. Many many possible 
constructs in source using an infinite number of random variable and 
function  names, could compile to the same object code. And there is no 
way to reinstate the comments either, so it becomes an exercise 
ultimately in hand editing and reinstating the comments manually - 
almost as big a job as writing from scratch.

I suspect this is how Linux writers write freeware drivers for 
proprietary hardware. Disassemble the manufacturers drivers, and at 
least mimic the program flow, if not the actual source code.


-- 
     “I know that most men, including those at ease with problems of the 
greatest complexity, can seldom accept even the simplest and most 
obvious truth if it be such as would oblige them to admit the falsity of 
conclusions which they have delighted in explaining to colleagues, which 
they have proudly taught to others, and which they have woven, thread by 
thread, into the fabric of their lives.”

     ― Leo Tolstoy

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Thread

AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-04 11:00 +0000
  Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-04 11:42 +0000
  Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-04 13:08 +0000
    Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-04 17:51 +0000
      Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-04 21:57 +0000
        Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-04 22:23 +0000
          Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-04 23:09 +0000
        Re: AI and decompilation? Dan Espen <dan1espen@gmail.com> - 2021-01-04 17:50 -0500
          Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-04 23:00 +0000
            Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-04 16:59 -0700
            Re: AI and decompilation? J. Clarke <jclarke.873638@gmail.com> - 2021-01-04 20:42 -0500
              Re: AI and decompilation? Dan Espen <dan1espen@gmail.com> - 2021-01-04 20:59 -0500
            Re: AI and decompilation? Dan Espen <dan1espen@gmail.com> - 2021-01-04 20:55 -0500
              Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-05 10:38 +0000
                Re: AI and decompilation? Bob Eager <news0073@eager.cx> - 2021-01-05 12:46 +0000
                Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-05 13:43 +0000
                Re: AI and decompilation? Bob Eager <news0073@eager.cx> - 2021-01-05 14:23 +0000
                Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 15:22 +0000
                Re: AI and decompilation? Dan Espen <dan1espen@gmail.com> - 2021-01-05 09:05 -0500
            Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-05 10:51 +0000
              Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-05 11:52 +0000
              Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 12:06 +0000
              Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-05 20:12 +0000
          Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 11:45 +0000
            Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-05 14:25 -0700
        Re: AI and decompilation? J. Clarke <jclarke.873638@gmail.com> - 2021-01-04 20:38 -0500
          Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 11:54 +0000
          Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-05 14:06 -0700
            Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 22:52 +0000
        Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-05 10:29 +0000
  Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-04 11:05 -0500
    Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-04 17:07 +0000
      Re: AI and decompilation? scott@slp53.sl.home (Scott Lurndal) - 2021-01-04 17:52 +0000
        Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-05 10:28 +0000
          Re: AI and decompilation? Thomas Koenig <tkoenig@netcologne.de> - 2021-01-05 13:06 +0000
            Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-05 13:41 +0000
            Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 15:30 +0000
              Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-05 16:42 +0000
                Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-05 20:12 +0000
                Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 20:20 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-05 22:23 +0000
                Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-06 00:14 +0000
                Re: AI and decompilation? Eli the Bearded <*@eli.users.panix.com> - 2021-01-06 02:17 +0000
                Re: AI and decompilation? Björn Lundin <b.f.lundin@gmail.com> - 2021-01-08 14:39 +0100
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-08 15:07 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-08 15:56 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-08 15:35 +0000
                Re: AI and decompilation? Eli the Bearded <*@eli.users.panix.com> - 2021-01-08 20:02 +0000
                Re: AI and decompilation? Björn Lundin <b.f.lundin@gmail.com> - 2021-01-10 15:12 +0100
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 09:36 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 10:43 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 18:09 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 18:29 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 18:37 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 21:03 +0000
                Re: AI and decompilation? Björn Lundin <b.f.lundin@gmail.com> - 2021-01-08 14:45 +0100
                Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-08 18:06 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-08 18:44 +0000
                Re: AI and decompilation? A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-09 03:02 +0000
                Re: AI and decompilation? A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-09 02:58 +0000
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-06 18:35 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 18:39 +0000
                Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-06 19:03 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 19:08 +0000
                Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-06 19:19 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-07 04:07 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-07 12:59 +0000
                Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-08 21:41 -0500
                Re: AI and decompilation? Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-09 12:25 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-09 12:46 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 15:49 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-09 18:33 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 19:20 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-09 21:05 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 23:19 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-10 12:17 +0000
                Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-09 16:54 -0500
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 23:48 +0000
                Re: AI and decompilation? A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-10 02:00 +0000
                Re: AI and decompilation? druck <news@druck.org.uk> - 2021-01-09 18:36 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 19:28 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-10 12:15 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-10 12:33 +0000
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-10 13:18 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-10 14:01 +0000
                Re: AI and decompilation? TimS <timstreater@greenbee.net> - 2021-01-10 15:14 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-10 13:59 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-10 14:46 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-10 15:34 +0000
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-10 15:05 +0000
                Re: AI and decompilation? Axel Berger <Spam@Berger-Odenthal.De> - 2021-01-10 17:28 +0100
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-11 17:25 +0000
                Re: AI and decompilation? TimS <timstreater@greenbee.net> - 2021-01-10 15:13 +0000
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-10 15:35 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-10 15:35 +0000
                Re: AI and decompilation? TimS <timstreater@greenbee.net> - 2021-01-10 17:23 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-10 18:17 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-11 03:44 +0000
                Re: AI and decompilation? TimS <timstreater@greenbee.net> - 2021-01-11 11:00 +0000
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-11 03:36 +0000
                Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-01-06 21:34 +0000
                Re: AI and decompilation? druck <news@druck.org.uk> - 2021-01-06 18:37 +0000
                Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-08 21:09 -0500
                Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-06 09:32 +0000
                Re: AI and decompilation? Björn Lundin <b.f.lundin@gmail.com> - 2021-01-08 14:56 +0100
            Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-05 14:25 -0700
            Re: AI and decompilation? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-01-06 14:17 +0200
              Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-06 12:42 +0000
                Re: AI and decompilation? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-01-06 16:42 +0200
                Re: AI and decompilation? "Kerr-Mudd,John" <notsaying@127.0.0.1> - 2021-01-08 09:48 +0000
                Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-08 10:27 +0000
              Re: AI and decompilation? usenet@only.tnx (Questor) - 2021-01-08 21:40 +0000
          Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-05 14:06 -0700
            Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-05 22:27 +0000
              Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-06 00:14 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 08:25 +0000
                Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-08 21:52 -0500
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-09 15:37 +0000
                Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-10 06:40 -0700
              Re: AI and decompilation? scott@slp53.sl.home (Scott Lurndal) - 2021-01-06 15:15 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 16:09 +0000
                Re: AI and decompilation? scott@slp53.sl.home (Scott Lurndal) - 2021-01-06 17:07 +0000
                Re: AI and decompilation? Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 17:38 +0000
          Re: AI and decompilation? druck <news@druck.org.uk> - 2021-01-05 21:20 +0000
    Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-04 17:47 +0000
    Re: AI and decompilation? Dan Espen <dan1espen@gmail.com> - 2021-01-04 14:18 -0500
      Re: AI and decompilation? Peter Flass <peter_flass@yahoo.com> - 2021-01-04 16:54 -0700
    Re: AI and decompilation? Theo <theom+news@chiark.greenend.org.uk> - 2021-01-04 23:01 +0000
  Re: AI and decompilation? Eli the Bearded <*@eli.users.panix.com> - 2021-01-04 20:11 +0000
  Re: AI and decompilation? Richard Kettlewell <invalid@invalid.invalid> - 2021-01-05 09:07 +0000
    Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-05 09:47 +0000
      Re: AI and decompilation? Richard Kettlewell <invalid@invalid.invalid> - 2021-01-05 11:13 +0000
        Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 12:12 +0000
          Re: AI and decompilation? Richard Kettlewell <invalid@invalid.invalid> - 2021-01-05 13:39 +0000
            Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 15:32 +0000
              Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 15:40 +0000
          Re: AI and decompilation? scott@slp53.sl.home (Scott Lurndal) - 2021-01-05 16:02 +0000
        Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-05 18:27 +0000
        Re: AI and decompilation? Vir Campestris <vir.campestris@invalid.invalid> - 2021-01-05 21:15 +0000
          Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 22:54 +0000
    Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 11:56 +0000
      Re: AI and decompilation? A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-05 14:11 +0000
        Re: AI and decompilation? Bob Eager <news0073@eager.cx> - 2021-01-05 14:22 +0000
        Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 15:35 +0000
          Re: AI and decompilation? Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-05 18:47 +0000
            Re: AI and decompilation? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-05 20:15 +0000
    Re: AI and decompilation? J. Clarke <jclarke.873638@gmail.com> - 2021-01-05 07:32 -0500
    Re: AI and decompilation? scott@slp53.sl.home (Scott Lurndal) - 2021-01-05 16:00 +0000
  Re: AI and decompilation? Adrian Caspersz <email@here.invalid> - 2021-01-05 11:26 +0000
    Re: AI and decompilation? Thomas Koenig <tkoenig@netcologne.de> - 2021-01-05 13:07 +0000
      Re: AI and decompilation? The Natural Philosopher <tnp@invalid.invalid> - 2021-01-05 13:42 +0000
      Re: AI and decompilation? Eli the Bearded <*@eli.users.panix.com> - 2021-01-05 18:31 +0000
  Re: AI and decompilation? "K. Krause" <klemens.krause@gmx.net> - 2021-01-05 16:01 +0100
  Re: AI and decompilation? druck <news@druck.org.uk> - 2021-01-05 20:51 +0000
    Re: AI and decompilation? gareth evans <headstone255@yahoo.com> - 2021-01-05 22:51 +0000
      Re: AI and decompilation? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-08 22:23 -0500
  Re: AI and decompilation? Andy Burns <usenet@andyburns.uk> - 2021-02-12 15:40 +0000

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