ES6 symbols: Implement Symbol intrinsic and basic functionality

src/arm/builtins-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1026 matching lines @@
 
     // If the result is a smi, it is *not* an object in the ECMA sense.
     // r0: result
     // sp[0]: receiver (newly allocated object)
     // sp[1]: constructor function
     // sp[2]: number of arguments (smi-tagged)
     __ JumpIfSmi(r0, &use_receiver);
 
     // If the type of the result (stored in its map) is less than
     // FIRST_SPEC_OBJECT_TYPE, it is not an object in the ECMA sense.
-    __ CompareObjectType(r0, r3, r3, FIRST_SPEC_OBJECT_TYPE);
+    __ CompareObjectType(r0, r1, r3, FIRST_SPEC_OBJECT_TYPE);
     __ b(ge, &exit);
 
+    // Symbols are "objects".
+    __ CompareInstanceType(r1, r3, SYMBOL_TYPE);
+    __ b(eq, &exit);
+
     // Throw away the result of the constructor invocation and use the
     // on-stack receiver as the result.
     __ bind(&use_receiver);
     __ ldr(r0, MemOperand(sp));
 
     // Remove receiver from the stack, remove caller arguments, and
     // return.
     __ bind(&exit);
     // r0: result
     // sp[0]: receiver (newly allocated object)
@@ skipping 790 matching lines @@
   __ bind(&dont_adapt_arguments);
   __ Jump(r3);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM