[LLVMdev] C Backend Ressurected

[Carback, Richard T., III]

James - you should check out fracture (Binary -> LLVM IR open source project):

https://github.com/draperlaboratory/fracture

Another tool of this type is McSema:

https://github.com/trailofbits/mcsema 

And yet another is Dagger:

http://dagger.repzret.org/ 

I'm biased towards the first as it's mine, and I know we're looking for contributors!

Thanks,

-R

> -----Original Message-----
> From: James Courtier-Dutton [mailto:james.dutton at gmail.com]
> Sent: Wednesday, September 03, 2014 5:13 PM
> To: Carback, Richard T., III
> Cc: llvmdev at cs.uiuc.edu
> Subject: Re: [LLVMdev] C Backend Ressurected
> 
> On 18 August 2014 15:18, Carback, Richard T., III <rcarback at draper.com>
> wrote:
> > Hi All,
> >
> > 2 of my summer interns (Aimee Dipietro and Greg Simpson) used their
> > time over the summer to resurrect the LLVM C Backend:
> >
> > https://github.com/draperlaboratory/llvm-cbe
> >
> > Improvements include recovery of simple for/while loops (instead of
> > goto), better variable naming, inline asm support, and making it work
> > on a more recent version of llvm. I believe they used the repository
> > here as a starting point:
> >
> > https://github.com/glycerine/llvm/tree/cbe_revival
> >
> > Feedback is welcomed. I would like to see this feature put back into
> > LLVM, and any help on how to make that happen would be appreciated.
> >
> >
> I am not sure implementing a C backend is really what you want.
> LLVM IR is in SSA CFG form.
> I would have thought that the next step would have been trying to
> convert it into AST, i.e. The format CLANG uses.
> Once it is in AST, it is trivial to output in C or whatever other
> language/format you wish.
> I know going from CFG to AST is hard, but I think that would be a better
> problem to solve.
> As building AST from CFG is very different from building a C backend, I
> would have though that it might have been good to use LLVM as a library
> to read the LLVM IR format, manipulate the CFG into other forms that are
> more AST friendly, and then write your own classes to then convert that
> to AST.
> Once in AST form, you could then use existing refactoring tools to then
> output more readable C source code.
> 
> Well, that is just my idea, I am currently writing a tool to go from
> Binary to LLVM IR. Once I have that done, I was going to do the next
> tool to go from LLVM IR to AST.
> 
> Kind Regards
> 
> James