[Truffle] Implemented BasicObject#instance_exec.

Author: nirvdrum

spec/truffle/tags/core/basicobject/instance_exec_tags.txt

@@ -221,6 +221,24 @@ public Object instanceEval(VirtualFrame frame, Object receiver, UndefinedPlaceho
 
     }
 
+    @CoreMethod(names = "instance_exec", needsBlock = true, argumentsAsArray = true)
+    public abstract static class InstanceExecNode extends YieldingCoreMethodNode {
+
+        public InstanceExecNode(RubyContext context, SourceSection sourceSection) {
+            super(context, sourceSection);
+        }
+
+        public InstanceExecNode(InstanceExecNode prev) {
+            super(prev);
+        }
+
+        @Specialization
+        public Object instanceExec(VirtualFrame frame, Object receiver, Object[] arguments, RubyProc block) {
+            return yieldWithModifiedSelf(frame, block, receiver, arguments);
+        }
+
+    }
+
     @CoreMethod(names = "method_missing", needsBlock = true, argumentsAsArray = true, visibility = Visibility.PRIVATE)
     public abstract static class MethodMissingNode extends CoreMethodNode {
 

truffle/src/main/java/org/jruby/truffle/nodes/core/BasicObjectNodes.java

@@ -49,4 +49,8 @@ public boolean yieldIsTruthy(VirtualFrame frame, RubyProc block, Object... argum
         return booleanCast(frame, yield(frame, block, arguments));
     }
 
+    public Object yieldWithModifiedSelf(VirtualFrame frame, RubyProc block, Object self, Object... arguments) {
+        return dispatchNode.dispatchWithModifiedSelf(frame, block, self, arguments);
+    }
+
 }

truffle/src/main/java/org/jruby/truffle/nodes/core/YieldingCoreMethodNode.java

@@ -135,14 +135,6 @@ def _offset_to_milliseconds
 
 ENV['TZ'] = 'UTC'
 
-class BasicObject
-
-  def instance_exec(*args)
-    # TODO (nirvdrum 06-Mar-15) Properly implement this.  The stub is just to get the specs even loading.
-  end
-
-end
-
 class Method
 
   def to_proc