Revert "Inline instance object hash code into object header on 64 bit."

runtime/vm/simulator_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
@@ skipping 1207 matching lines @@
 }
 
 
 intptr_t Simulator::ReadExclusiveX(uword addr, Instr* instr) {
   MutexLocker ml(exclusive_access_lock_);
   SetExclusiveAccess(addr);
   return ReadX(addr, instr);
 }
 
 
-intptr_t Simulator::ReadExclusiveW(uword addr, Instr* instr) {
-  MutexLocker ml(exclusive_access_lock_);
-  SetExclusiveAccess(addr);
-  return ReadWU(addr, instr);
-}
-
-
 intptr_t Simulator::WriteExclusiveX(uword addr, intptr_t value, Instr* instr) {
   MutexLocker ml(exclusive_access_lock_);
   bool write_allowed = HasExclusiveAccessAndOpen(addr);
   if (write_allowed) {
     WriteX(addr, value, instr);
     return 0;  // Success.
   }
   return 1;  // Failure.
 }
 
 
-intptr_t Simulator::WriteExclusiveW(uword addr, intptr_t value, Instr* instr) {
-  MutexLocker ml(exclusive_access_lock_);
-  bool write_allowed = HasExclusiveAccessAndOpen(addr);
-  if (write_allowed) {
-    WriteW(addr, value, instr);
-    return 0;  // Success.
-  }
-  return 1;  // Failure.
-}
-
-
 uword Simulator::CompareExchange(uword* address,
                                  uword compare_value,
                                  uword new_value) {
   MutexLocker ml(exclusive_access_lock_);
   // We do not get a reservation as it would be guaranteed to be found when
   // writing below. No other thread is able to make a reservation while we
   // hold the lock.
   uword value = *address;
   if (value == compare_value) {
     *address = new_value;
@@ skipping 943 matching lines @@
     set_wregister(rt, static_cast<int32_t>(val), R31IsZR);
   }
 }
 
 
 void Simulator::DecodeLoadStoreExclusive(Instr* instr) {
   if ((instr->Bit(23) != 0) || (instr->Bit(21) != 0) || (instr->Bit(15) != 0)) {
     UNIMPLEMENTED();
   }
   const int32_t size = instr->Bits(30, 2);
-  if (size != 3 && size != 2) {
+  if (size != 3) {
     UNIMPLEMENTED();
   }
+
   const Register rs = instr->RsField();
   const Register rn = instr->RnField();
   const Register rt = instr->RtField();
   const bool is_load = instr->Bit(22) == 1;
   if (is_load) {
     // Format(instr, "ldxr 'rt, 'rn");
-    if (size == 3) {
-      const int64_t addr = get_register(rn, R31IsSP);
-      intptr_t value = ReadExclusiveX(addr, instr);
-      set_register(instr, rt, value, R31IsSP);
-    } else {
-      const int64_t addr = get_register(rn, R31IsSP);
-      intptr_t value = ReadExclusiveW(addr, instr);
-      set_register(instr, rt, value, R31IsSP);
-    }
+    const int64_t addr = get_register(rn, R31IsSP);
+    intptr_t value = ReadExclusiveX(addr, instr);
+    set_register(instr, rt, value, R31IsSP);
   } else {
     // Format(instr, "stxr 'rs, 'rt, 'rn");
-    if (size == 3) {
-      uword value = get_register(rt, R31IsSP);
-      uword addr = get_register(rn, R31IsSP);
-      intptr_t status = WriteExclusiveX(addr, value, instr);
-      set_register(instr, rs, status, R31IsSP);
-    } else {
-      uint32_t value = get_register(rt, R31IsSP);
-      uword addr = get_register(rn, R31IsSP);
-      intptr_t status = WriteExclusiveW(addr, value, instr);
-      set_register(instr, rs, status, R31IsSP);
-    }
+    uword value = get_register(rt, R31IsSP);
+    uword addr = get_register(rn, R31IsSP);
+    intptr_t status = WriteExclusiveX(addr, value, instr);
+    set_register(instr, rs, status, R31IsSP);
   }
 }
 
 
 void Simulator::DecodeLoadStore(Instr* instr) {
   if (instr->IsLoadStoreRegOp()) {
     DecodeLoadStoreReg(instr);
   } else if (instr->IsLoadStoreRegPairOp()) {
     DecodeLoadStoreRegPair(instr);
   } else if (instr->IsLoadRegLiteralOp()) {
@@ skipping 1436 matching lines @@
   set_register(NULL, CODE_REG, code);
   set_register(NULL, PP, pp);
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(USING_SIMULATOR)
 
 #endif  // defined TARGET_ARCH_ARM64