llvm dev - Sep 2008 - [LLVMdev] LLVS newbie adding a new target

Hi

I am interested in developing a new target for LLVM and wanted to check 
where my new code should reside.  Should I just add a new sub-directory 
to lib/Targets and populate that with the necessary files?  I am using 
ARM as a template, as I am most familiar with that architecture, so I 
assume copying files from that directory is a good starting point.

I have tried a trivial build of a new target based on ARM by copying all 
the ARM target files to a new directory and changing names of files in 
the code to create a "new" target.  After adding the new target to the
TARGETS_TO_BUILD list in "configure", I was able to "make" a
new build
that included the new target.  Of course it is just a copy of the ARM 
target at this stage but it confirms I have grasped the basics of the 
LLVM tree and build process.

My concern is that, if there is a new release of LLVM, I will need to 
re-integrate my source into it.  At this stage this looks fairly trivial 
to do but I do now want to get caught out in the future by ploughing on 
without checking there is not a more intelligent way to organise my code 
that I have overlooked.

Cheers,

 - Dyson

On Tue, Sep 2, 2008 at 9:05 AM, Dyson Wilkes <dyson at akya.co.uk>
wrote:
> Hi
>
> I am interested in developing a new target for LLVM and wanted to check
> where my new code should reside.  Should I just add a new sub-directory
> to lib/Targets and populate that with the necessary files?
Yup! That would be the place.
>  I am using
> ARM as a template, as I am most familiar with that architecture, so I
> assume copying files from that directory is a good starting point.
>
Your assumption is correct. :-)
> I have tried a trivial build of a new target based on ARM by copying all
> the ARM target files to a new directory and changing names of files in
> the code to create a "new" target.  After adding the new target
to the
> TARGETS_TO_BUILD list in "configure", I was able to
"make" a new build
> that included the new target.  Of course it is just a copy of the ARM
> target at this stage but it confirms I have grasped the basics of the
> LLVM tree and build process.
>
> My concern is that, if there is a new release of LLVM, I will need to
> re-integrate my source into it.  At this stage this looks fairly trivial
> to do but I do now want to get caught out in the future by ploughing on
> without checking there is not a more intelligent way to organise my code
> that I have overlooked.
>
No, what you're doing is the best approach. If you want, you can live
off of the SVN top-of-tree. Then you won't have to worry about merging
with a new release problems. You also get the benefit of being on top
of changes that could affect the interface to your new back-end. Of
course, there could be breakage having nothing to do with your
back-end that you'll have to deal with. So there are trade-offs.

-bw