[LLVMdev] How to use MCJIT by default for a target

[David Tweed]

Hi Andrew,

On 18/09/12 11:21, David Tweed wrote:
> in particular there are some regression tests of interesting things
> -- such as profiling -- that fail purely because the default old JIT
> doesn't work.

|I've actually got LLVM currently compiling within an ARM QEmu install to 
|look at an assert within the ARM JIT code.  Profiling tests that I 
|submitted a few weeks ago are failing on ARM build-bots (assert in lli), 
|perhaps this is what you are referring to.
|
|If I can verify that the tests pass when using MCJIT is there any 
|interest in fixing it?  Obviously if they still break with MCJIT there 
|is something which definitely needs fixed.

Yep, this is the issue. Running on an ARM pandaboard I can confirm that it's
due
to issues with the old JIT in general which are fixed in MCJIT, and nothing
to do
with the profiling code being tested, as discussed in this thread:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120910/150406.
html

As you can see, I'm very interested in getting this fixed, but it's one of
those situations where there's not really any nice mechanism in place for
the
obvious solution, which is to use MCJIT when needed without requiring the
user (or for regression tests, tester) to do anything special.

Any ideas anyone has would be great!

Cheers,
David