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

runtime/vm/simulator_arm64.cc

Index: runtime/vm/simulator_arm64.cc
diff --git a/runtime/vm/simulator_arm64.cc b/runtime/vm/simulator_arm64.cc
index 99912dfa29c7793730771114aadda99ba69cde83..6125bae52ac4fba69e5680780976a6192c5cf3f1 100644
--- a/runtime/vm/simulator_arm64.cc
+++ b/runtime/vm/simulator_arm64.cc
@@ -1225,13 +1225,6 @@ intptr_t Simulator::ReadExclusiveX(uword addr, Instr* 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);
@@ -1243,17 +1236,6 @@ intptr_t Simulator::WriteExclusiveX(uword addr, intptr_t value, Instr* instr) {
 }
 
 
-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) {
@@ -2217,37 +2199,25 @@ void Simulator::DecodeLoadStoreExclusive(Instr* instr) {
     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);
   }
 }