A64: Synchronize with r17807.

src/a64/ic-a64.cc

 // Copyright 2013 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 1535 matching lines @@
   Register key = x1;
   Register receiver = x2;
   Register receiver_map = x3;
   Register elements = x4;
   Register elements_map = x5;
 
   __ JumpIfNotSmi(key, &slow);
   __ JumpIfSmi(receiver, &slow);
   __ Ldr(receiver_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
 
-  // Check that the receiver does not require access checks. We need to do this
-  // because this generic stub does not perform map checks.
+  // Check that the receiver does not require access checks and is not observed.
+  // The generic stub does not perform map checks or handle observed objects.
   __ Ldrb(x10, FieldMemOperand(receiver_map, Map::kBitFieldOffset));
-  __ Tbnz(x10, Map::kIsAccessCheckNeeded, &slow);
+  __ TestAndBranchIfAnySet(
+      x10, (1 << Map::kIsAccessCheckNeeded) | (1 << Map::kIsObserved), &slow);
 
   // Check if the object is a JS array or not.
   Register instance_type = x10;
   __ CompareInstanceType(receiver_map, instance_type, JS_ARRAY_TYPE);
   __ B(eq, &array);
   // Check that the object is some kind of JSObject.
   __ Cmp(instance_type, FIRST_JS_OBJECT_TYPE);
   __ B(lt, &slow);
 
   // Object case: Check key against length in the elements array.
@@ skipping 251 matching lines @@
     ASSERT(to_patch->Mask(TestBranchMask) == TBNZ);
     // This is JumpIfSmi(smi_reg, branch_imm).
     patcher.tbz(smi_reg, 0, branch_imm);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64