[Info-vax] C99 stuff (Re: The Road to V9.0)

[John Reagan]

On Sunday, June 9, 2019 at 4:59:50 PM UTC-4, Craig A. Berry wrote:
> On 6/9/19 10:30 AM, John Reagan wrote:
> 
> > You won't need any of our changes to clang/clang++ if you are just
> > interested in porting over open source code. No open source code has
> > OpenVMS'isms buried in it. However, if you want RTL name prefixing,
> > etc., you'll need our edits. Since we will be providing a full
> > clang/clang++, getting it from VSI will be the easy way. Nobody here  > wanting to hack new stuff into clang?
> 
> I wouldn't think so, but people might want to do all the same things for
> other languages that VSI doesn't plan to provide.  Let's say for the
> sake of argument the powers that be command you to produce a
> VMS-friendly Objective C compiler.  Are you going to forget everything
> you did to bring up clang/clang++ and never look at the code you've
> already written?
> 

LLVM out of the box needs a little help for VMS (adding an arg-count for example), but clang out of the box would probably work just fine on OpenVMS if you use "-c" to keep the driver from trying to invoke the linker, etc.  And you won't get prefixing.  There is nothing we'll add to clang that would be of interest to somebody porting swift for example.

> Now turn it around (since you're unlikely to ever have that mandate) and
> say someone else wants to do it.  Wouldn't they benefit from being able
> to just take what you've done and adapt it?  Even things that you may be
> pushing back into LLVM (generating debug code that works for the OpenVMS
> debugger?), would be a lot easier to do from a working example.  Sure,
> people can probably figure it all out for themselves if they devote the
> resources to doing so, but wouldn't it be to everyone's advantage if
> they didn't have to?
> 

The VMS debugger will be able to swallow the DWARF4 (and eventually the DWARF5) from LLVM.  If not, the debugger is broken.  I expect that you can take the LLVM with OpenVMS additions and hook up any frontend to it that you want.