[LLVMdev] JIT on armhf, again

[Tim Northover]

> Should llc default to
> generating code which will actually run on a given platform? Is it
> possible my version of llvm has been compiled with the wrong options?

It's a configure-time option, I believe. It's entirely possible the
Debian packages have it wrong, but I'd always have and test with an
override: if I could make a default work that would just be bonus
success.

> Does the system support linking together multiple modules with different
> triples?

Not really. You'll probably get some code out the other end, but with
a pretty much randomly chosen triple. More features along those lines
are planned (it's useful for CPU-specific routines, particularly
during LTO).

>> Did you try setting a breakpoint in that function I mentioned and
>> finding out just which test fails on the path to returning AAPCS_VFP?
>
> No; I don't have a debugger on this platform.

That's probably the first thing I'd look at fixing.

Beyond that, before even thinking about implementing a JITing
compiler, I'd build LLVM with debugging symbols and make sure I build
against that.

LLVM's API just isn't packaged for people to use as a black box. It's
the ad-hoc mixture of all the bells and whistles existing users have
found useful, without the important ones being marked.

I could suggest various diagnostics at this point, but they'd all come
back to a debugger very quickly.

Cheers.

Tim.