A64: Port LSeqStringSetChar optimizations from r16707 and r17521.

src/a64/macro-assembler-a64.h

 // Copyright 2013 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 1455 matching lines @@
   // Picks out an array index from the hash field.
   // Register use:
   //   hash - holds the index's hash. Clobbered.
   //   index - holds the overwritten index on exit.
   void IndexFromHash(Register hash, Register index);
 
   // ---------------------------------------------------------------------------
   // Inline caching support.
 
   void EmitSeqStringSetCharCheck(Register string,
-                                 Register index,    // Smi
+                                 Register index,
+                                 Register scratch,

[ulan, 2014/02/06 14:23:43]

This is different from arm port, which takes value register here and doesn't use
it.

                                  uint32_t encoding_mask);
 
   // 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);
 
   // Hash the interger value in 'key' register.
@@ skipping 708 matching lines @@
 #error "Unsupported option"
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 #endif  // V8_A64_MACRO_ASSEMBLER_A64_H_