[LLVMdev] Contributing new backend to LLVM

[Chris Lattner]

On Nov 1, 2011, at 11:44 AM, Tony Linthicum wrote:
> Hello all,
> 
> We would like to contribute a new backend for Qualcomm's Hexagon 
> processor.  We will actively maintain the port once it is accepted. 
> Hexagon is a VLIW core that is used principally in modem and low power 
> audio applications in Qualcomm's chip sets.
> 
> We have a patch for both llvm and for clang.  As this is a new port, 
> these patches are quite large (approximately 26k and 3k lines, 
> respectively).  Most of the patches consist of, quite naturally, new 
> files.  I have looked for guidelines for submitting a new backend, but 
> have not found anything.  Is there anything of that nature?  If not, my 
> plan is to simply submit the two patches.  Any other suggestions?

Hi Tony,

If relevant, I'd suggest splitting it up as:

1. Changes to LLVM code outside your target directory.
2. Your new target directory.
3. Clang patches.

As others have pointed out, you really do need some basic regression tests to make sure that the backend is working.  Also, make sure to update this:
http://llvm.org/docs/CodeGenerator.html#targetfeatures

and add a new section to that document on your target.

Thanks!

-Chris