--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -1082,17 +1082,22 @@ mjit::Compiler::generateMethod()
           }
           END_CASE(JSOP_DEFFUN)
 
           BEGIN_CASE(JSOP_LAMBDA)
           {
             JSFunction *fun = script->getFunction(fullAtomIndex(PC));
             prepareStubCall(Uses(0));
             masm.move(ImmPtr(fun), Registers::ArgReg1);
-            stubCall(stubs::Lambda);
+
+            JSOp next = JSOp(PC[JSOP_LAMBDA_LENGTH]);
+            if (next == JSOP_INITMETHOD)
+                stubCall(stubs::LambdaForInit);
+            else
+                stubCall(stubs::Lambda);
             frame.takeReg(Registers::ReturnReg);
             frame.pushTypedPayload(JSVAL_TYPE_OBJECT, Registers::ReturnReg);
           }
           END_CASE(JSOP_LAMBDA)
 
           BEGIN_CASE(JSOP_TRY)
           END_CASE(JSOP_TRY)
 

--- a/js/src/methodjit/StubCalls.cpp
+++ b/js/src/methodjit/StubCalls.cpp
@@ -1508,16 +1508,40 @@ stubs::RegExp(VMFrame &f, JSObject *rege
     JS_ASSERT(proto);
     JSObject *obj = js_CloneRegExpObject(f.cx, regex, proto);
     if (!obj)
         THROWV(NULL);
     return obj;
 }
 
 JSObject * JS_FASTCALL
+stubs::LambdaForInit(VMFrame &f, JSFunction *fun)
+{
+    JSObject *obj = FUN_OBJECT(fun);
+
+    JSObject *parent;
+    if (FUN_NULL_CLOSURE(fun)) {
+        parent = f.fp->scopeChain;
+
+        if (obj->getParent() == parent)
+            return obj;
+    } else {
+        parent = js_GetScopeChain(f.cx, f.fp);
+        if (!parent)
+            THROWV(NULL);
+    }
+
+    obj = CloneFunctionObject(f.cx, fun, parent);
+    if (!obj)
+        THROWV(NULL);
+
+    return obj;
+}
+
+JSObject * JS_FASTCALL
 stubs::Lambda(VMFrame &f, JSFunction *fun)
 {
     JSObject *obj = FUN_OBJECT(fun);
 
     JSObject *parent;
     if (FUN_NULL_CLOSURE(fun)) {
         parent = f.fp->scopeChain;
     } else {

--- a/js/src/methodjit/StubCalls.h
+++ b/js/src/methodjit/StubCalls.h
@@ -104,16 +104,17 @@ void JS_FASTCALL IncElem(VMFrame &f);
 void JS_FASTCALL DecElem(VMFrame &f);
 void JS_FASTCALL CallProp(VMFrame &f, JSAtom *atom);
 
 void JS_FASTCALL DefFun(VMFrame &f, uint32 index);
 JSObject * JS_FASTCALL DefLocalFun(VMFrame &f, JSFunction *fun);
 JSObject * JS_FASTCALL DefLocalFun_FC(VMFrame &f, JSFunction *fun);
 JSObject * JS_FASTCALL RegExp(VMFrame &f, JSObject *regex);
 JSObject * JS_FASTCALL Lambda(VMFrame &f, JSFunction *fun);
+JSObject * JS_FASTCALL LambdaForInit(VMFrame &f, JSFunction *fun);
 JSObject * JS_FASTCALL FlatLambda(VMFrame &f, JSFunction *fun);
 void JS_FASTCALL Arguments(VMFrame &f);
 void JS_FASTCALL ArgSub(VMFrame &f, uint32 n);
 void JS_FASTCALL EnterBlock(VMFrame &f, JSObject *obj);
 void JS_FASTCALL LeaveBlock(VMFrame &f);
 
 void JS_FASTCALL VpInc(VMFrame &f, Value *vp);
 void JS_FASTCALL VpDec(VMFrame &f, Value *vp);