Use asserts instead of branches to avoid fast array methods for observed arrays

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 16e672c16f6f7e2f25131de106e28d609b484aca..188528b6e0cb0e1eda448271c5a0213f9e1f0354 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -525,12 +525,9 @@ BUILTIN(ArrayPush) {
   }
   if (!maybe_elms_obj->To(&elms_obj)) return maybe_elms_obj;
 
-  if (FLAG_harmony_observation &&
-      JSObject::cast(receiver)->map()->is_observed()) {
-    return CallJsBuiltin(isolate, "ArrayPush", args);
-  }
-
   JSArray* array = JSArray::cast(receiver);
+  ASSERT(!array->map()->is_observed());
+
   ElementsKind kind = array->GetElementsKind();
 
   if (IsFastSmiOrObjectElementsKind(kind)) {
@@ -642,10 +639,7 @@ BUILTIN(ArrayPop) {
   if (!maybe_elms->To(&elms_obj)) return maybe_elms;
 
   JSArray* array = JSArray::cast(receiver);
-
-  if (FLAG_harmony_observation && array->map()->is_observed()) {
-    return CallJsBuiltin(isolate, "ArrayPop", args);
-  }
+  ASSERT(!array->map()->is_observed());
 
   int len = Smi::cast(array->length())->value();
   if (len == 0) return heap->undefined_value();
@@ -680,10 +674,7 @@ BUILTIN(ArrayShift) {
     return CallJsBuiltin(isolate, "ArrayShift", args);
   }
   JSArray* array = JSArray::cast(receiver);
-
-  if (FLAG_harmony_observation && array->map()->is_observed()) {
-    return CallJsBuiltin(isolate, "ArrayShift", args);
-  }
+  ASSERT(!array->map()->is_observed());
 
   int len = Smi::cast(array->length())->value();
   if (len == 0) return heap->undefined_value();
@@ -734,15 +725,12 @@ BUILTIN(ArrayUnshift) {
     return CallJsBuiltin(isolate, "ArrayUnshift", args);
   }
   JSArray* array = JSArray::cast(receiver);
+  ASSERT(!array->map()->is_observed());
   if (!array->HasFastSmiOrObjectElements()) {
     return CallJsBuiltin(isolate, "ArrayUnshift", args);
   }
   FixedArray* elms = FixedArray::cast(elms_obj);
 
-  if (FLAG_harmony_observation && array->map()->is_observed()) {
-    return CallJsBuiltin(isolate, "ArrayUnshift", args);
-  }
-
   int len = Smi::cast(array->length())->value();
   int to_add = args.length() - 1;
   int new_length = len + to_add;
@@ -938,10 +926,7 @@ BUILTIN(ArraySplice) {
     return CallJsBuiltin(isolate, "ArraySplice", args);
   }
   JSArray* array = JSArray::cast(receiver);
-
-  if (FLAG_harmony_observation && array->map()->is_observed()) {
-    return CallJsBuiltin(isolate, "ArraySplice", args);
-  }
+  ASSERT(!array->map()->is_observed());
 
   int len = Smi::cast(array->length())->value();