[cfe-dev] [Cocci] Re: using with c++ codebase ?

[Julia Lawall]

On Sun, 28 Nov 2010, Chris Lattner wrote:

> 
> On Nov 28, 2010, at 9:24 AM, Carl-Daniel Hailfinger wrote:
> 
> > Hi,
> > 
> > I added the llvm cfe-dev mailing list to CC so you can get answers
> > directly from the source.
> > The quoted mail is archived at
> > http://lists.diku.dk/pipermail/cocci/2010-November/001348.html and you
> > can go forward/backward in the archive if you want to see more context.
> 
> I don't know much about Coccinelle, but Clang certainly does track accurate source locations, including the original and ultimate location of macro expansions:
> http://clang.llvm.org/docs/InternalsManual.html#SourceLocation
> 
> Clang was built with the intention of supporting refactoring in the future, and we have a suite of source code rewriting applications already in tree.

Thanks for the feedback.  What is wanted is not just the locations of 
code, but the actual whitespace, comments, and macros that were around the 
code?  If that information is not currently kept by the clang parser, 
might it be easy to add?

And to what extent does the AST resemble the source code?  Is there a 
simplified intermediate language, or is there a production in the AST for 
every production in the concrete syntax?

thanks,
julia

> -Chris 
> 
> > 
> > On 27.11.2010 22:49, Julia Lawall wrote:
> >> On Sat, 27 Nov 2010, Carl-Daniel Hailfinger wrote:
> >> 
> >>> On 27.11.2010 17:46, Julia Lawall wrote:
> >>> 
> >>>> On Sat, 27 Nov 2010, Jani Monoses wrote
> >>>> 
> >>>>> On 11/27/2010 02:44 PM, Julia Lawall wrote:
> >>>>> 
> >>>>> 
> >>>>>> I think it is possible, and indeed a C++ parser has been written that is
> >>>>>> compatible with Coccinelle.  Doing the simple case as you suggest is even
> >>>>>> probably not too hard.  But at the moment we do not have the resources to
> >>>>>> look into it.
> >>>>>> 
> >>>>>> 
> >>>>> thanks for the prompt reply.
> >>>>> Is the C++ parser code available along with some documentation on how it can
> >>>>> be used with Coccinelle?
> >>>>> 
> >>>>> 
> >>>> There is no documentation.  Furthermore, it is only a parser, it does not 
> >>>> construct an abstract syntax tree, so compatible with Coccinelle may not 
> >>>> mean much more than it is written in ocaml.  I think it is available, but 
> >>>> I am not sure where.  Perhaps Nicolas or Yoann can answer.
> >>>> 
> >>>> 
> >>> This may be a dumb question, but is there any reason the C++ parser in
> >>> llvm/clang can't be used? It is compatible with gcc, and AFAIK it is
> >>> rather easy to make it spit out an AST in the format you want.
> >>> The LLVM developers are very open to suggestions, and many people have
> >>> used LLVM in their own projects.
> >>> Apparently LLVM ships with OCaml bindings by default, so it may not be
> >>> too hard to use it.
> >>> 
> >> 
> >> Perhaps it relies on CPP (ie expansion of macros) having been performed in 
> >> advance?  Coccinelle needs to parse the code as it is, not parse it into 
> >> some simplified internal representation, so that it can reconstruct the 
> >> code after transformation.  This includes keeping information about all 
> >> whitespace and comments.
> >> 
> > 
> > 
> > Regards,
> > Carl-Daniel
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> 
>