JRuby 9k JIT breaks defined?

[nirvdrum]

I ran into an issue where defined? stops working properly with JIT enabled in JRuby 9k. The following simple script is enough to illustrate the problem:

X = true

1000.times do
  raise 'X undefined' unless defined?(::X)
end

puts 'Success'

With JIT disabled, "Succes" will be printed to the screen. With it enabled, I see the following:

RuntimeError: X undefined
  jit_defined_bug.rb_CLOSURE_1__jit_defined_bug.rb_0 at jit_defined_bug.rb:4
                                               times at org/jruby/RubyFixnum.java:296
                                          __script__ at jit_defined_bug.rb:3

Ruby version:

$ ruby -v
jruby 9000.dev-SNAPSHOT (2.1.2p142) 2014-11-04 dc55205 Java HotSpot(TM) 64-Bit Server VM 25.25-b02 on 1.8.0_25-b17 +jit [linux-amd64]

[nirvdrum]

It appears defined?(X) (rather than defined?(::X)) is not susceptible to the problem.

[headius]

There's a fix in for the failure in JIT, but additional work is needed on the IR.

[headius]

We can't remember or determine what's actually needed to "finish" this, so we're going to close it. The fix in place is simple and works, and if any defined? bugs remain they'd need to be fixed in IR first anyway.