Static linking

[rainbreak]

Relates to ethereum/webthree-umbrella#337.

Work towards having a STATIC_LINKING compile flag.

Split into sub PRs:

• more useful arg order for finding packages #158 for switching find package args
• make curl dependency link modular #159 for the separate UseCURL.cmake
• add cmake Find/Use for system libraries #160 for extra cmake finders
• Specify full curl dependencies #161 for explicit curl dependencies
• add static link logic #163 for add_executable macro to enable static link options

[bobsummerwill]

Thanks, @rainbeam!

We're going to need to break this up a bit, and merge it in piece by piece.

Also looks like we'll need some extra platform conditionals around this extra FindX.cmake. For my own http://github.com/doublethinkco/cpp-ethereum-cross cross-builds, it's quite a similar story. Static linkage and cross-builds require you to get ALL THE WAY to the end of your dependency chain.

So let's start with the simplest changes. Please could you explain the reordering of the library and include paths? Is the ordering meaningful there? I am not very experienced with CMake specifically, so I honestly don't know. I am happy to do those reorderings if that is more idiomatic.

Perhaps you could make a new PR with ONLY those reorderings, and we can merge that right away, to reduce the volume of diffs under review.

[bobsummerwill]

The new files should also be independently mergable too, so how about making a second PR which only adds the following?

• FindSSH2.cmake
• UseOpenSSL.cmake
• UseSSH2.cmake
• UseZLIB.cmake

You could also include the edits to these files too at the same time:

• UseCURL.cmake
• UseJsonRpc.cmake

As long as you REMOVE those lines in UseCURL.cmake which chain the dependencies onto SSH2, OpenSSL and SSH2. Then that merge wouldn't break anything.

[bobsummerwill]

When those two PRs are merged, we would just be left with the "chained dependencies" to work through, which would probably need some extra platform and modal conditionals around them.

And we would have to do the conditional-thing for switching mode (ie. something to do an equivalent of ethereum/webthree#163 and https://github.com/ethereum/webthree-umbrella/pull/493/files) but nicely.

[rainbreak]

Thanks for the comments. Agree on splitting up.

Edit: progress list moved to top ^

[bobsummerwill]

Hey @rainbeam!

Looks at the diffs in this PR now.

Want to make a third one for everything EXCEPT those 3 lines in UseCURL.cmake?

[rainbreak]

OK will do. What does it take to trigger a build on here? I see it has 'triggered' but it doesn't seem to be doing anything.

[bobsummerwill]

Nothing required. It's just backlogged, I think. See http://ethbuilds.com.

[bobsummerwill]

See http://52.28.164.97/job/webthree-helpers-prs/.

[rainbreak]

Added the static linking logic. Uses a flag -DSTATIC_LINKING=TRUE to enable.

7d5b89b comes from #163 and is a requirement for f1e99c1. I can rebase if we decide to do #163 differently.

[bobsummerwill]

That looks great. Why don't you just move the content of these diffs into 163 and squash it, and we can merge that? Then we're just missing the optional dependencies bit.

[rainbreak]

@bobsummerwill: once #163 is merged shall I go ahead and make changes like in ethereum/webthree#163 across the whole umbrella?

[bobsummerwill]

All sub-tasks are complete. Should just be a matter of modifying the CMake files for particular executables now, to switch them to the new macro.

[bobsummerwill]

^ It's probably only worth doing eth and maybe ethminer, isn't it? What other executables did you have in mind?

Full list of EXEs I know of:

• eth
• ethminer
• ethkey
• ethvm
• testeth
• rlp
• bench
• testweb3core
• solc
• lllc
• soltest
• AlethZero
• mix-ide

[rainbreak]

Will do solc / soltest as well (as that's what started this whole thing off).

[rainbreak]

Can see argument for not doing mix / alethzero. The others I'm ambivalent about.

[bobsummerwill]

Yeah ... so I think soltest, solc, lllc would be a good set. ethminer too if that is easy?

But yeah ... diminishing returns for everything else.

Thanks!