Fix zero hash handling on ARM.

src/x64/code-stubs-x64.cc

 // Copyright 2011 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 4985 matching lines @@
   __ leal(hash, Operand(hash, hash, times_8, 0));
   // hash ^= hash >> 11;
   __ movl(scratch, hash);
   __ shrl(scratch, Immediate(11));
   __ xorl(hash, scratch);
   // hash += hash << 15;
   __ movl(scratch, hash);
   __ shll(scratch, Immediate(15));
   __ addl(hash, scratch);
 
-  uint32_t kHashShiftCutOffMask = (1 << (32 - String::kHashShift)) - 1;
-  __ andl(hash, Immediate(kHashShiftCutOffMask));
+  __ andl(hash, Immediate(String::kHashBitMask));
 
   // if (hash == 0) hash = 27;
   Label hash_not_zero;
   __ j(not_zero, &hash_not_zero);
-  __ Set(hash, 27);
+  __ Set(hash, StringHasher::kZeroHash);
   __ bind(&hash_not_zero);
 }
 
 void SubStringStub::Generate(MacroAssembler* masm) {
   Label runtime;
 
   // Stack frame on entry.
   //  rsp[0]: return address
   //  rsp[8]: to
   //  rsp[16]: from
@@ skipping 1211 matching lines @@
                                  xmm0,
                                  &slow_elements);
   __ ret(0);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64