Allows unboxed doubles to be disabled.

runtime/vm/simulator_arm.h

Index: runtime/vm/simulator_arm.h
===================================================================
--- runtime/vm/simulator_arm.h	(revision 36258)
+++ runtime/vm/simulator_arm.h	(working copy)
@@ -94,11 +94,6 @@
                bool fp_return = false,
                bool fp_args = false);
 
-  // Implementation of atomic compare and exchange in the same synchronization
-  // domain as other synchronization primitive instructions (e.g. ldrex, strex).
-  static uword CompareExchange(uword* address,
-                               uword compare_value,
-                               uword new_value);
 
   // Runtime and native call support.
   enum CallKind {
@@ -208,39 +203,6 @@
   inline intptr_t ReadW(uword addr, Instr* instr);
   inline void WriteW(uword addr, intptr_t value, Instr* instr);
 
-  // Synchronization primitives support.
-  void ClearExclusive();
-  intptr_t ReadExclusiveW(uword addr, Instr* instr);
-  intptr_t WriteExclusiveW(uword addr, intptr_t value, Instr* instr);
-
-  // TODO(regis): Remove exclusive access support machinery if not needed.
-  // In Dart, there is at most one thread per isolate.
-  // We keep track of 16 exclusive access address tags across all isolates.
-  // Since we cannot simulate a native context switch, which clears
-  // the exclusive access state of the local monitor (using the CLREX
-  // instruction), we associate the isolate requesting exclusive access to the
-  // address tag. Multiple isolates requesting exclusive access (using the LDREX
-  // instruction) to the same address will result in multiple address tags being
-  // created for the same address, one per isolate.
-  // At any given time, each isolate is associated to at most one address tag.
-  static Mutex* exclusive_access_lock_;
-  static const int kNumAddressTags = 16;
-  static struct AddressTag {
-    Isolate* isolate;
-    uword addr;
-  } exclusive_access_state_[kNumAddressTags];
-  static int next_address_tag_;
-
-  // Set access to given address to 'exclusive state' for current isolate.
-  static void SetExclusiveAccess(uword addr);
-
-  // Returns true if the current isolate has exclusive access to given address,
-  // returns false otherwise. In either case, set access to given address to
-  // 'open state' for all isolates.
-  // If given addr is NULL, set access to 'open state' for current
-  // isolate (CLREX).
-  static bool HasExclusiveAccessAndOpen(uword addr);
-
   // Executing is handled based on the instruction type.
   void DecodeType01(Instr* instr);  // Both type 0 and type 1 rolled into one.
   void DecodeType2(Instr* instr);