Reproduction of good and bad jit

bad_jit.out

FG-386:rubinius acoyle$ ruby -Xjit.inline.debug repro.rb
JIT: compiling Array#include? (1440519539.55320)
| inline slot read: offset: 40
| inline slot read: offset: 24
| inlining: Fixnum#+ into include?. primitive fixnum_add (Fixnum)
| inline slot read: offset: 32
| inlining: Fixnum#< into include?. primitive fixnum_compare_operation (Fixnum)
| inlining: Rubinius::Tuple#[] into include?. primitive tuple_at (Rubinius::Tuple)
| inlining: Kernel#equal? into include?. primitive object_equal (Symbol)
| inlining: String#== into include?. generic primitive: jit_stub_string_equal (String)
| inlining: Fixnum#+ into include?. primitive fixnum_add (Fixnum)
A.equals? a_obj: true
A.equals? p_obj: true
JIT: compiling A#equals? (1440519539.79684)
| inlining: Kernel#kind_of? into equals?. primitive Object#kind_of (A)
|| inlining: no cache for kind_of fast path
| NOT inlining: Proxy#is_a? into equals?. unhandled executable type
A.equals? p_obj: false

good_jit.out

### This is with the call to A.equals? a_obj commented out

FG-386:rubinius acoyle$ ruby -Xjit.inline.debug repro.rb
JIT: compiling Array#include? (1440519532.636447)
| inline slot read: offset: 40
| inline slot read: offset: 24
| inlining: Fixnum#+ into include?. primitive fixnum_add (Fixnum)
| inline slot read: offset: 32
| inlining: Fixnum#< into include?. primitive fixnum_compare_operation (Fixnum)
| inlining: Rubinius::Tuple#[] into include?. primitive tuple_at (Rubinius::Tuple)
| inlining: Kernel#equal? into include?. primitive object_equal (Symbol)
| inlining: String#== into include?. generic primitive: jit_stub_string_equal (String)
| inlining: Fixnum#+ into include?. primitive fixnum_add (Fixnum)
A.equals? p_obj: true
JIT: compiling A#equals? (1440519532.658641)
| NOT inlining: Proxy#is_a? into equals?. unhandled executable type
A.equals? p_obj: true

repro.rb

class A
  def self.equals?(object)
    object.is_a?(self)
  end
end

class Object
  def jit(obj, sym, block=nil)
    yield if block_given?

    Rubinius::JIT.compile obj, obj.method(sym).executable, block
  end
end

class Proxy
  undef_method 'is_a?'

  def initialize(c)
    @target = c
  end

  def method_missing(method, *args, &block)
    @target.send(method, *args, &block)
  end
end

a_obj = A.new
p_obj = Proxy.new(a_obj)

# if this is commented out then the jit works correctly, and A.equals p_obj will work
puts "A.equals? a_obj: #{A.equals? a_obj}"
puts "A.equals? p_obj: #{A.equals? p_obj}" # returns true -- right

jit(A, :equals?)

puts "A.equals? p_obj: #{A.equals? p_obj}" # returns false -- wrong

spec.rb

# in spec/jit/method_spec.rb

context "to m() containing is_a?" do
  before :each do
    @klass = Class.new do
      def self.m(obj)
        obj.is_a?(self)
      end
    end

    @o = @klass.new

    jit(@klass, :m) { @klass.m(@o) }
  end

  it 'compiles' do
    @klass.method(:m).executable.jitted?.should be_true
  end

  it "returns true for an object of its type" do
    @klass.m(@o).should be_true
  end

  it "returns true for a proxy object" do
    proxy = Class.new do
      undef_method 'is_a?'
      def method_missing(method, *args, &block)
        @o.send(method, *args, &block)
      end
    end

    @klass.m(proxy.new).should be_true
  end
end