Re: Getting source file from the object file

Richard Tobin wrote:

In article
<58bb918e-5b7f-476b-8c76-2148cc496e5e@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
user923005 <dcorbit@xxxxxxxxx> wrote:

Now, it is probably impossible to decompile 100%, because it has been
shown to be equivalent to the "does the turing machine halt?" problem.

What?

Obviously decompilation is impossible in a sense, because different
source programs can produce the same object file.

Equally obviously, it is theoretically possible to find a source
program which produces that code by enumerating all the source
programs and compiling them until we find one which produces the
desired object file. (Assuming of course that the object file really
is the result of compiling a source file.)

Nitpick: this assumes that the object code depends /only/ on the source
code, and not (say) on the user that compiled it, or the time it was
compiled, or the IP address of the machine it was compiled on -- all of
which /might/ be left, as provenance, in the object code.

I agree that decompilation is not a halting-problem issue. On the other
hand, we might want a slightly faster algorithm than blind search ...

--
RIP Ian Carr, 21-Apr-1933 -- 25-Feb-2009 /Out of the Long Dark/

Hewlett-Packard Limited registered office: Cain Road, Bracknell,
registered no: 690597 England Berks RG12 1HN

.

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