Add Linux ARM targets

[lloeki]

Possible on GHA via qemu and/or xbuild. Also available on Travis.

Considered targets:

• aarch64
• armv7
• armv8

[lloeki]

Currently built manually inside an aarch64 Linux VM on a M1 Mac Mini. Appears to run fine on Linux on ARM hardware (Graviton) but has trouble at runtime on emulated machines (via qemu on x86 and/or docker's hyperkit on M1)

[lloeki]

Cross-compiling builds correctly, but I hit a missing symbol error.

root@5e26cbbca17e:/mini_racer# bundle exec rake test
/usr/local/bin/ruby: symbol lookup error: /mini_racer/lib/mini_racer_extension.so: undefined symbol: _ZN2v82V818SetFlagsFromStringEPKcm
rake aborted!
root@5e26cbbca17e:/mini_racer# echo _ZN2v82V818SetFlagsFromStringEPKcm | c++filt 
v8::V8::SetFlagsFromString(char const*, unsigned long)

[lloeki]

It seems compilation was partial, the intermediate libv8_monolith.a target might have been insufficient for cross-compilation to fully proceed (e.g api.o from v8_base_without_compiler was only present in obj.host and absent from obj.target), but running a full make produced all the required .o in obj.target.

[tisba]

Currently built manually inside an aarch64 Linux VM on a M1 Mac Mini. Appears to run fine on Linux on ARM hardware (Graviton) but has trouble at runtime on emulated machines (via qemu on x86 and/or docker's hyperkit on M1)

Just a tiny remark: Docker for Desktop does also have experimental support for Big Sur/MacOS virtualization.framework. The same problem exists there though. Docker's hyperkit VM was/is based on hypervisor.framework.

[lloeki]

Got a build and a gem working! Not publishing yet because things are not ready automation-side but testers are welcome to make themselves known.

[lloeki]

@tisba I have Linux cross compilation to ARM on x64 CI working, see this run (there are some failures but they're on Darwin and Alpine, gnu/ARM passes!)

Before I pull the trigger and publish these, can you download the gem-16.3.0.0-aarch64-linux down the summary page and try it out as you did over there?

[tisba]

For some reason I'm getting an error when I try to process the gem (gem generate_index). I'll take a closer look later.

$ gem generate_index
ERROR:  Unable to process /app/repo/gems/libv8-node-16.3.0.0-aarch64-linux.gem
"\xF7\xA0\aw\xB7\x83\xBBs" is not an octal string (ArgumentError)
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_header.rb:129:in `strict_oct'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_header.rb:107:in `from'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:59:in `each'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:112:in `find'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:112:in `seek'
        /usr/local/lib/ruby/3.0.0/rubygems/package.rb:544:in `read_checksums'
        /usr/local/lib/ruby/3.0.0/rubygems/package.rb:604:in `block (2 levels) in verify'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:27:in `new'
        /usr/local/lib/ruby/3.0.0/rubygems/package.rb:603:in `block in verify'
[…]

[lloeki]

There's another build based on 16.4.2 over there: https://github.com/sqreen/ruby-libv8-node/actions/runs/1023202498

[tisba]

I'm not sure what I'm doing "wrong" 😞

I downloaded https://github.com/sqreen/ruby-libv8-node/suites/3216862858/artifacts/74504625 as gems/gem-16.4.2.0-aarch64-linux.gem and run gem generate_index (both natively on M1 and x86 Ruby 3.0.2 or via docker run -it --rm -v "$(pwd)":/app -w /app ruby:3.0.2) and still getting the same error...

ERROR:  Unable to process /app/gems/gem-16.4.2.0-aarch64-linux.gem
"f:bff<\xA2#" is not an octal string (ArgumentError)
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_header.rb:129:in `strict_oct'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_header.rb:107:in `from'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:59:in `each'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:112:in `find'
        /usr/local/lib/ruby/3.0.0/rubygems/package/tar_reader.rb:112:in `seek'
        /usr/local/lib/ruby/3.0.0/rubygems/package.rb:544:in `read_checksums'

To sanity check, I downloaded https://rubygems.org/downloads/rails-6.1.4.gem and gem generate_index (and gem unpack) works. Does this work for you, @lloeki? What am I missing?

• ruby --version 3.0.2p107
• gem --version 3.2.23

[tisba]

Any ideas, @lloeki?

[lloeki]

Sorry for the delay @tisba, I did not have a moment to look at this but I'm not forgetting about it!

[lloeki]

@tisba I pushed some 16.10.0 gems and updated the mini_racer PR.