ES6 symbols: Implement Symbol intrinsic and basic functionality

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index d001e0ae8fec3c7b95f8d05c615a4a87702f2a02..035bde2234ee41bc4f190823309e5656ecba84ec 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -6038,8 +6038,15 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
       __ CompareRoot(input, Heap::kNullValueRootIndex);
       __ b(eq, true_label);
     }
-    __ CompareObjectType(input, input, scratch,
-                         FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
+    if (FLAG_harmony_symbols) {
+      __ CompareObjectType(input, input, scratch, SYMBOL_TYPE);
+      __ b(eq, true_label);
+      __ CompareInstanceType(input, scratch,
+                             FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
+    } else {
+      __ CompareObjectType(input, input, scratch,
+                           FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
+    }
     __ b(lt, false_label);
     __ CompareInstanceType(input, scratch, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ b(gt, false_label);