macOS Sierra - Address build breaks

[bobsummerwill]

The next release of macOS will be released this summer, called macOS Sierra, with the OS name having been changed from OS X back to macOS, and the casing aligned with the other Apple operating systems (iOS, watchOS, tvOS).

See https://en.wikipedia.org/wiki/MacOS_Sierra.

See https://gitter.im/ethereum/cpp-ethereum?at=577be0b264f940856a11269e for first report of issues with Sierra.

[EtherTyper]

Appears to hang forever, then I finally get:

../include/string:1938:44: error: 'basic_string<_CharT, _Traits, _Allocator>' is missing exception specification 'noexcept(is_nothrow_copy_constructible<allocator_type>::value)'
basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
                                       ^
../include/string:1326:40: note: previous declaration is here
_LIBCPP_INLINE_VISIBILITY explicit basic_string(const allocator_type& __a)

[EtherTyper]

Wait a second... I realized LLVM isn't run by Ethereum, (I'm a serious newb,) but then I found out it might be an issue with a file included form LLVM, the standard C++ implementation! Don't know why std::basic_string's failure to compile doesn't break anything else... If you need to try anything else on Sierra, let me be your test dummy! 😆

[chfast]

Looks like problem with libc++.

Can you provide a minimal test?

Is Xcode available on macOS Sierra?

[EtherTyper]

@chfast Yup, it's a libc++ issue. Running Xcode 8 beta, June 13.

[EtherTyper]

What kind of fix should I test?

[chfast]

Anything that shows that standard header is broken. To report to LLVM or
Xcode.

On Wed, Jul 6, 2016, 20:58 ELI JOSEPH BRADLEY notifications@github.com
wrote:

What kind of fix should I test?

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[bobsummerwill]

Hey @EtherTyper,

So let's start with a bug report at https://github.com/Homebrew/homebrew-core/issues/new. If you follow that URL you will see that they have a template for such reports, with the output from brew gist-logs being the main thing which we would need from you.

So you should be able to replicate the issue, I think, with brew install llvm37 on Sierra, which would be a simpler use-case for us to start with.

Please could you see if you can replicate the issue with brew install llvm37 and get the gist logs from that? If you do that, I am happy to be the one to actually log the issue with Homebrew.

And that might well lead to us needing to submit a bug report for LLVM itself, as per http://llvm.org/docs/HowToSubmitABug.html.

I am happy to do all the issue reporting work, but we'll need to lean on your for the actual logs, etc, because you have the Sierra install.

PS. If you want to workaround this in cpp-ethereum the meantime, you should be able to do brew install cpp-ethereum --without-evmjit. I think that command is right, eh, @chfast?

[EtherTyper]

@bobsummerwill Will post the link to the gist after the test!

[EtherTyper]

@bobsummerwill So, I fixed LLVM building problems. I untarred the libcxx tarball and fixed the error about the absence of exception declaration by adding the exception declaration to line 1938, as the error suggested. After making an updated tarball, I edited the llvm37.rb formula to the following, to match the SHAs correctly. Here's a patch to the current homebrew-versions repository showing the changes:

From 7a8123f838ca82e0155112a10798d0cd1bfb78cc Mon Sep 17 00:00:00 2001
From: Eli Joesph Bradley <elijos03@gmail.com>
Date: Sat, 9 Jul 2016 08:34:15 -1000
Subject: [PATCH] Update llvm37 formula

---
 llvm37.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm37.rb b/llvm37.rb
index c4e07db..db9d897 100644
--- a/llvm37.rb
+++ b/llvm37.rb
@@ -57,7 +57,7 @@ class Llvm37 < Formula

     resource "libcxx" do
       url "http://llvm.org/releases/3.7.1/libcxx-3.7.1.src.tar.xz"
-      sha256 "357fbd4288ce99733ba06ae2bec6f503413d258aeebaab8b6a791201e6f7f144"
+      sha256 "1ad27d1af083a3aff63606fdad76c631a2218e69041f34aef670ec22ade61ae6"
     end

     if MacOS.version <= :snow_leopard
-- 
2.9.0

However, alas, I get more errors: https://gist.github.com/07c22c353ef33d895fe1730c0dff7995

And this time, I don't believe this is a dependency error. There might be some incompatibility with my Xcode 8 building tools and the webthree-umbrella source code. Thanks!

[bobsummerwill]

Great!

Yes, you are hitting what appears to be a build error at HEAD which I am looking at right now :-)

Join us on https://gitter.im/ethereum/cpp-ethereum for updates!

[bobsummerwill]

So, you needed an edit in libc++ within LLVM. Is that right?

Here's the source tree ... https://github.com/llvm-mirror/llvm/tree/release_38

What was your edit?

[EtherTyper]

@bobsummerwill I modified a 3.7.1 tarball, so diffing against the 3.8 trunk would probably make git unnecessarily puke out priorly documented changes... Long story short, I edited the basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a) function at line 1938 to have the noexcept(is_nothrow_copy_constructible<allocator_type>::value) exception declaration it required.

[EtherTyper]

I'll get around to submitting a Phabricator patch to LLVM tomorrow.

[bobsummerwill]

Thanks! Much appreciated. Will be great to have Sierra working ahead of time.

If you could report the issue to Homebrew, they can patch around it in the meantime. LLVM release cadence seems very slow, but LLVM is broadly used, so I imagine the Homebrew team would want this to be in a good state on Sierra.

[EtherTyper]

@bobsummerwill Already tried. They refused to help because my brew doctor said I was running Sierra, which they don't support. Homebrew/homebrew-core#2826

[EtherTyper]

Here's the LLVM patch I submitted:

http://reviews.llvm.org/D22200

[bobsummerwill]

Thanks for both of those, @EtherTyper!

A little surprising on Sierra, because I would have thought they would want to get started, but no doubt they have a plan of attack.

I'll keep this issue open pending movement on the LLVM issue.

[EtherTyper]

@bobsummerwill Update: Homebrew acknowledged the issue when someone who was running a stable build of macOS encountered the same thing... Homebrew/homebrew-versions#1298

[bobsummerwill]

This issue was moved to ethereum/aleth#3191