Fixed crashes exposed though fuzzing.

src/arm/macro-assembler-arm.h

 // Copyright 2012 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 643 matching lines @@
   // Must preserve the result register.
   void PopTryHandler();
 
   // Passes thrown value to the handler of top of the try handler chain.
   void Throw(Register value);
 
   // Propagates an uncatchable exception to the top of the current JS stack's
   // handler chain.
   void ThrowUncatchable(Register value);
 
+  // Throw a message string as an exception.
+  void Throw(BailoutReason reason);
+
+  // Throw a message string as an exception if a condition is not true.
+  void ThrowIfNot(Condition cc, BailoutReason reason);
+
   // ---------------------------------------------------------------------------
   // Inline caching support
 
   // Generate code for checking access rights - used for security checks
   // on access to global objects across environments. The holder register
   // is left untouched, whereas both scratch registers are clobbered.
   void CheckAccessGlobalProxy(Register holder_reg,
                               Register scratch,
                               Label* miss);
 
@@ skipping 660 matching lines @@
       Label* failure);
 
   // Check if instance type is sequential ASCII string and jump to label if
   // it is not.
   void JumpIfInstanceTypeIsNotSequentialAscii(Register type,
                                               Register scratch,
                                               Label* failure);
 
   void JumpIfNotUniqueName(Register reg, Label* not_unique_name);
 
+  void EmitSeqStringSetCharCheck(Register string,
+                                 Register index,
+                                 Register value,
+                                 uint32_t encoding_mask);
+
   // ---------------------------------------------------------------------------
   // Patching helpers.
 
   // Get the location of a relocated constant (its address in the constant pool)
   // from its load site.
   void GetRelocatedValueLocation(Register ldr_location,
                                  Register result);
 
 
   void ClampUint8(Register output_reg, Register input_reg);
@@ skipping 162 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_