Re: [Caml-list] Dead code detection

[Alain Frisch <alain@frisch.fr>]

At LexiFi, we use two different techniques for detecting dead code:

  - Bisect, for a dynamic notion of "dead code" (i.e. code which is not 
exercised by our testsuite).

  - A custom static detection tool, which parses .cmt and .cmi files to 
detect exported components (values, exceptions, etc) used by no other 
module in the project.  This is of course combined with the existing 
compiler warnings on locally unused and non-exported declarations.


The next version of OCaml will make it extremely simple to implement 
such a static detection tool.  This is because of the new -keep-locs 
compiler flag, which allows us to keep the location of exported values 
in .cmi files, and thus retrieve the same locations on references to 
such values in .cmt files.  It makes it very easy to create the link 
between an exported value and its references in external modules, even 
if this goes through e.g. module inclusions.  As a proof of concept of 
this approach, we can already try the tool 
experimental/frisch/unused_exported_values.ml in the trunk:

http://caml.inria.fr/cgi-bin/viewvc.cgi/ocaml/trunk/experimental/frisch/unused_exported_values.ml?revision=HEAD&view=markup


(-keep-locs also gives "for free" a jump-to-definition feature, just by 
parsing .cmt or .annot files.)


Hope this helps,

Alain




On 12/11/2013 03:52 PM, Pierre-Yves Strub wrote:
> Hi all,
>
> Does any of you know a tool for doing dead code detection?
>
> Thanks,
> -- Pierre-Yves.
>
>