Update to LLVM 8

[hydai]

Close #182

Hi,
I've updated LLVM from 5.0.0 to 8.0.0. And I'm very interested in how to test evmjit. Is there any test suite?

[chfast]

I've updated LLVM from 5.0.0 to 8.0.0. And I'm very interested in how to test evmjit. Is there any test suite?

EVMJIT supports EVMC API so you can use testeth tool from Aleth project to test it. E.g. testeth -- --vm ./evmjit.so.

The problem is the EVMC version here is quite old and not ABI compatible with the latest EVMC 6. The EVMC would need to be upgraded here. You might also want to find some older binaries of Aleth or find a version of Aleth where EVMJIT was still includes as git submodule and then just update the submodule with this PR.

[chfast]

Looks good, but without performing any functional tests it will be risky to merge this.

[chfast]

Where these functions removed from LLVM?

[hydai]

These functions are removed in this PR: https://reviews.llvm.org/D52184

[hydai]

Thanks for reviewing this PR.
I am going to add functional tests to verify this PR.

[axic]

@hydai perhaps you want to consider updating EVMC first to 6.3.0 and using evmone's evm-test to validate evmjit.

[hydai]

@axic Good idea. I am going to update EVMC and prepare the validation phase first.

[chfast]

I started investigating CI and LLVM 5.0 is hard to get for Ubuntu/Debian. LLVM 6.0 is the oldest version easily available. I think to make it easy we should either upgrade to LLVM 6.0 (minimal upgrade possible) or directly to 8 as in this PR.

[hydai]

I will check that the cost of upgrading to LLVM 6.0. If it's easy, then we just upgrade to LLVM 6.0 first.