Backport hash collision workaround to 3.6.

src/arm/macro-assembler-arm.h

 // 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 33 matching lines @@
 
 
 static inline Operand SmiUntagOperand(Register object) {
   return Operand(object, ASR, kSmiTagSize);
 }
 
 
 
 // Give alias names to registers
 const Register cp = { 8 };  // JavaScript context pointer
-const Register roots = { 10 };  // Roots array pointer.
+const Register kRootRegister = { 10 };  // Roots array pointer.
 
 // Flags used for the AllocateInNewSpace functions.
 enum AllocationFlags {
   // No special flags.
   NO_ALLOCATION_FLAGS = 0,
   // Return the pointer to the allocated already tagged as a heap object.
   TAG_OBJECT = 1 << 0,
   // The content of the result register already contains the allocation top in
   // new space.
   RESULT_CONTAINS_TOP = 1 << 1,
@@ skipping 278 matching lines @@
   void LoadContext(Register dst, int context_chain_length);
 
   void LoadGlobalFunction(int index, Register function);
 
   // Load the initial map from the global function. The registers
   // function and map can be the same, function is then overwritten.
   void LoadGlobalFunctionInitialMap(Register function,
                                     Register map,
                                     Register scratch);
 
+  void InitializeRootRegister() {
+    ExternalReference roots_address =
+        ExternalReference::roots_address(isolate());
+    mov(kRootRegister, Operand(roots_address));
+  }
+
   // ---------------------------------------------------------------------------
   // JavaScript invokes
 
   // Setup call kind marking in ecx. The method takes ecx as an
   // explicit first parameter to make the code more readable at the
   // call sites.
   void SetCallKind(Register dst, CallKind kind);
 
   // Invoke the JavaScript function code by either calling or jumping.
   void InvokeCode(Register code,
@@ skipping 782 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_