Fix defined?(::Object) logic in JIT. Partial fix for #2090.

The current IR for this logic uses the runtime helper call isDefinedConstantOrMethod, which can trigger exceptions on its own (if e.g. the method lookup triggers an error?). Because of that handler, this bug in the JIT was caught and swallowed, resulting in the defined? returning nil. That is not correct behavior; only the exceptions we would expect to be raised by these lookups should be caught. In addition, I don't believe the :: form can be used to call methods (::foo doesn't parse), so the use of exception handling and isDefinedConstOrMethod may be inappropriate here.
jruby · Nov 4, 2014 · c3b80aa · c3b80aa
1 parent 0e4c83c
commit c3b80aa
Showing 2 changed files with 7 additions and 2 deletions.
diff --git a/core/src/main/java/org/jruby/ir/targets/JVMVisitor.java b/core/src/main/java/org/jruby/ir/targets/JVMVisitor.java
@@ -1573,10 +1573,9 @@ public void RuntimeHelperCall(RuntimeHelperCall runtimehelpercall) {
                 break;
             case IS_DEFINED_CONSTANT_OR_METHOD:
                 jvmMethod().loadContext();
-                jvmMethod().loadSelf();
                 visit(runtimehelpercall.getArgs()[0]);
                 jvmAdapter().ldc(((StringLiteral)runtimehelpercall.getArgs()[1]).getString());
-                jvmAdapter().invokestatic(p(IRRuntimeHelpers.class), "isDefinedConstantOrMethod", sig(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, String.class));
+                jvmAdapter().invokestatic(p(IRRuntimeHelpers.class), "isDefinedConstantOrMethod", sig(IRubyObject.class, ThreadContext.class, IRubyObject.class, String.class));
                 jvmStoreLocal(runtimehelpercall.getResult());
                 break;
             case IS_DEFINED_NTH_REF:

diff --git a/spec/compiler/general_spec.rb b/spec/compiler/general_spec.rb
@@ -866,4 +866,10 @@ class JRUBY4925
       expect(x).to eq Object
     end
   end
+
+  it "retrieves toplevel constants with ::Const form" do
+    run '::Object' do |x|
+      expect(x).to eq Object
+    end
+  end
 end