...unfortunately...

In the process of getting the JIT to work properly without the AddLocalVarLoadStore pass, I ran into an issue with Block getting set into DynamicScope and blowing up (caused by OptimizeDelegation, fixed in 88a8896). In fixing that I realized that this particular method was always requiring a dynamic scope, for no obvious reason:

  def popen3(*cmd, **opts, &block)
    in_r, in_w = IO.pipe
    opts[:in] = in_r
    in_w.sync = true

    out_r, out_w = IO.pipe
    opts[:out] = out_w

    err_r, err_w = IO.pipe
    opts[:err] = err_w

    popen_run(cmd, opts, [in_r, out_w, err_w], [in_w, out_r, err_r], &block)
  end

It turned out that arity-checking of keyword arguments forced a DynamicScope so it could get to StaticScope. However, all Ruby bodies have direct access to their StaticScope now, so the DynamicScope was unnecessary.

Unfortunately, after I came up with this patch to remove that flag, I ran into another crash due to CheckLJE not reporting that it required DynamicScope.

I fixed that (on master) in 434e54e, but it just left me stranded on another mysterious failure in Rake's helpers.rb:

Error:

XXXXX

Method:

def permute_task(task_desc, task_type, base_name, options, *prereqs, &block)
  default_task = nil
  all_tasks = nil

  # iterate over all flag sets, noting default mapping
  tasks = {}
  options.each do |name, flags|
    if name == :default
      default_task = flags
      next
    end

    if name == :all
      all_tasks = flags
      next
    end

    test_task = task_type.new("#{base_name}:#{name}", &block).tap do |t|
      t.ruby_opts ||= []
      # THIS IS THE LINE THAT BLOWS UP
      flags.each do |flag|
        t.ruby_opts.unshift flag
      end
    end
    tasks[name] = test_task.name
    Rake::Task[test_task.name].tap do |t|
      t.add_description "#{flags.inspect}"
      t.prerequisites.concat prereqs
    end
  end

  # set up default, if specified
  if default_task
    desc "Run #{task_desc}s for #{default_task}"
    task base_name => tasks[default_task]
  end

  # set up "all", if specified, or make it run everything
  all_tasks ||= tasks.keys
  desc "Run #{task_desc}s for #{all_tasks.inspect}"
  task "#{base_name}:all" => all_tasks.map {|key| tasks[key]}
end

For some reason, variables are now getting crossed. The block param flags is getting mixed up with test_task later on, at least from the perspective of the inner block.

I have not provided the IR for brevity, but -Xir.print should be working properly now...build this branch and try to run anything with rake.

So, this is a work in progress. I expect this latest issue is another problem with scope optimizations killing a scope that should be there or vice versa...something that was masked before by the arity check's dynscope requirement. Any thoughts?

cc @subbuss @enebo