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

陳韋任 (Wei-Ren Chen) chenwj at iis.sinica.edu.tw
Fri Sep 21 01:12:05 PDT 2012

> |  I agree that we should clean up JIT/MCJIT tests, then change to MCJIT
> |until it pass those tests.
> That's a big idea, how this has come up is that there are some tests (in particular profiling) which AREN'T testing JITing itself, but need to use the JIT in order to run stuff. On ARM these don't run with the old JIT but do with the MCJIT. We could just disable the tests, but then we're losing coverage of the profiling stuff due to a "configuration limitation"... Particularly if more such tests are likely to be added, it'd be preferable to figure a way to "use the most robust JIT on the current platform" and run them.

  I see test cases under Analysis/Profiling/ directory just call `lli`
WITHOUT "-use-mcjit" option. Do you mean on ARM, lli use MCJIT by
default already? I thought we have to explicitly use "-use-mcjit"
option to make lli use MCJIT...

  As Eli said in [1], ExecutionEngine/* and ExecutionEngine/MCJIT/*
are same test cases for old JIT and MCJIT separately. I guess we can
choose the most robust JIT base on their result.


[1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-June/050878.html

Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

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