Get the ARM simulator to throw an exception on unaligned accesses.

src/simulator-arm.h

 // Copyright 2008 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 129 matching lines @@
                     int32_t left,
                     int32_t right,
                     bool addition);
 
   // Helper functions to decode common "addressing" modes
   int32_t GetShiftRm(Instr* instr, bool* carry_out);
   int32_t GetImm(Instr* instr, bool* carry_out);
   void HandleRList(Instr* instr, bool load);
   void SoftwareInterrupt(Instr* instr);
 
+  // Read and write memory.
+  inline uint8_t ReadBU(int32_t addr);
+  inline int8_t ReadB(int32_t addr);
+  inline void WriteB(int32_t addr, uint8_t value);
+  inline void WriteB(int32_t addr, int8_t value);
+
+  inline uint16_t ReadHU(int32_t addr);
+  inline int16_t ReadH(int32_t addr);
+  inline void WriteH(int32_t addr, uint16_t value);
+  inline void WriteH(int32_t addr, int16_t value);
+
+  inline int ReadW(int32_t addr);
+  inline void WriteW(int32_t addr, int value);
+
   // 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);
   void DecodeType3(Instr* instr);
   void DecodeType4(Instr* instr);
   void DecodeType5(Instr* instr);
   void DecodeType6(Instr* instr);
   void DecodeType7(Instr* instr);
 
   // Executes one instruction.
@@ skipping 14 matching lines @@
   // registered breakpoints
   Instr* break_pc_;
   instr_t break_instr_;
 };
 
 } }  // namespace assembler::arm
 
 #endif  // defined(__arm__)
 
 #endif  // V8_SIMULATOR_ARM_H_