Reland "ARM64: Add NEON support"

src/arm64/disasm-arm64.h

Index: src/arm64/disasm-arm64.h
diff --git a/src/arm64/disasm-arm64.h b/src/arm64/disasm-arm64.h
index 4b477bc438e8f181aa70a568ab650c7e23d052a9..c12d53b7e6073483931538ba9cd9d68cc8bed148 100644
--- a/src/arm64/disasm-arm64.h
+++ b/src/arm64/disasm-arm64.h
@@ -5,6 +5,7 @@
 #ifndef V8_ARM64_DISASM_ARM64_H
 #define V8_ARM64_DISASM_ARM64_H
 
+#include "src/arm64/assembler-arm64.h"
 #include "src/arm64/decoder-arm64.h"
 #include "src/arm64/instructions-arm64.h"
 #include "src/globals.h"
@@ -29,6 +30,13 @@ class DisassemblingDecoder : public DecoderVisitor {
  protected:
   virtual void ProcessOutput(Instruction* instr);
 
+  // Default output functions.  The functions below implement a default way of
+  // printing elements in the disassembly. A sub-class can override these to
+  // customize the disassembly output.
+
+  // Prints the name of a register.
+  virtual void AppendRegisterNameToOutput(const CPURegister& reg);
+
   void Format(Instruction* instr, const char* mnemonic, const char* format);
   void Substitute(Instruction* instr, const char* string);
   int SubstituteField(Instruction* instr, const char* format);