Revert of [Atomics] Implement ldaxr/stlxr instructions in ARM64 simulator

src/arm64/simulator-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ARM64_SIMULATOR_ARM64_H_
 #define V8_ARM64_SIMULATOR_ARM64_H_
 
 #include <stdarg.h>
 #include <vector>
 
@@ skipping 847 matching lines @@
   static const char* vreg_names[];
 
   // Debugger input.
   void set_last_debugger_input(char* input) {
     DeleteArray(last_debugger_input_);
     last_debugger_input_ = input;
   }
   char* last_debugger_input() { return last_debugger_input_; }
   char* last_debugger_input_;
 
-  // Synchronization primitives. See ARM DDI 0487A.a, B2.10. Pair types not
-  // implemented.
-  enum class MonitorAccess {
-    Open,
-    Exclusive,
-  };
-
-  enum class TransactionSize {
-    None = 0,
-    Byte = 1,
-    HalfWord = 2,
-    Word = 4,
-  };
-
-  TransactionSize get_transaction_size(unsigned size);
-
-  // The least-significant bits of the address are ignored. The number of bits
-  // is implementation-defined, between 3 and 11. See ARM DDI 0487A.a, B2.10.3.
-  static const uintptr_t kExclusiveTaggedAddrMask = ~((1 << 11) - 1);
-
-  class LocalMonitor {
-   public:
-    LocalMonitor();
-
-    // These functions manage the state machine for the local monitor, but do
-    // not actually perform loads and stores. NotifyStoreExcl only returns
-    // true if the exclusive store is allowed; the global monitor will still
-    // have to be checked to see whether the memory should be updated.
-    void NotifyLoad(uintptr_t addr);
-    void NotifyLoadExcl(uintptr_t addr, TransactionSize size);
-    void NotifyStore(uintptr_t addr);
-    bool NotifyStoreExcl(uintptr_t addr, TransactionSize size);
-
-   private:
-    void Clear();
-
-    MonitorAccess access_state_;
-    uintptr_t tagged_addr_;
-    TransactionSize size_;
-  };
-
-  class GlobalMonitor {
-   public:
-    GlobalMonitor();
-
-    class Processor {
-     public:
-      Processor();
-
-     private:
-      friend class GlobalMonitor;
-      // These functions manage the state machine for the global monitor, but do
-      // not actually perform loads and stores.
-      void Clear_Locked();
-      void NotifyLoadExcl_Locked(uintptr_t addr);
-      void NotifyStore_Locked(uintptr_t addr, bool is_requesting_processor);
-      bool NotifyStoreExcl_Locked(uintptr_t addr, bool is_requesting_processor);
-
-      MonitorAccess access_state_;
-      uintptr_t tagged_addr_;
-      Processor* next_;
-      Processor* prev_;
-      // A stxr can fail due to background cache evictions. Rather than
-      // simulating this, we'll just occasionally introduce cases where an
-      // exclusive store fails. This will happen once after every
-      // kMaxFailureCounter exclusive stores.
-      static const int kMaxFailureCounter = 5;
-      int failure_counter_;
-    };
-
-    // Exposed so it can be accessed by Simulator::{Read,Write}Ex*.
-    base::Mutex mutex;
-
-    void NotifyLoadExcl_Locked(uintptr_t addr, Processor* processor);
-    void NotifyStore_Locked(uintptr_t addr, Processor* processor);
-    bool NotifyStoreExcl_Locked(uintptr_t addr, Processor* processor);
-
-    // Called when the simulator is destroyed.
-    void RemoveProcessor(Processor* processor);
-
-   private:
-    bool IsProcessorInLinkedList_Locked(Processor* processor) const;
-    void PrependProcessor_Locked(Processor* processor);
-
-    Processor* head_;
-  };
-
-  LocalMonitor local_monitor_;
-  GlobalMonitor::Processor global_monitor_processor_;
-  static base::LazyInstance<GlobalMonitor>::type global_monitor_;
-
  private:
   void Init(FILE* stream);
 
   int  log_parameters_;
   Isolate* isolate_;
 };
 
 
 // When running with the simulator transition into simulated execution at this
 // point.
@@ skipping 28 matching lines @@
     Simulator::current(isolate)->PopAddress();
   }
 };
 
 #endif  // !defined(USE_SIMULATOR)
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ARM64_SIMULATOR_ARM64_H_