As a first step towards implementing thumb2, add code for...

src/arm/assembler-thumb2.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 490 matching lines @@
   };
 
  private:
   static unsigned supported_;
   static unsigned enabled_;
   static unsigned found_by_runtime_probing_;
 };
 
 
 typedef int32_t Instr;
+typedef int16_t ThumbInstr;
 
 
 extern const Instr kMovLrPc;
 extern const Instr kLdrPCPattern;
 
 
 class Assembler : public Malloced {
  public:
   // Create an assembler. Instructions and relocation information are emitted
   // into a buffer, with the instructions starting from the beginning and the
@@ skipping 62 matching lines @@
   }
 
   // Here we are patching the address in the constant pool, not the actual call
   // instruction.  The address in the constant pool is the same size as a
   // pointer.
   static const int kCallTargetSize = kPointerSize;
   static const int kExternalTargetSize = kPointerSize;
 
   // Size of an instruction.
   static const int kInstrSize = sizeof(Instr);
+  static const int kThumbSize = sizeof(ThumbInstr);
 
   // Distance between the instruction referring to the address of the call
   // target (ldr pc, [target addr in const pool]) and the return address
   static const int kCallTargetAddressOffset = kInstrSize;
 
   // Distance between start of patched return sequence and the emitted address
   // to jump to.
   static const int kPatchReturnSequenceAddressOffset = kInstrSize;
 
   // Difference between address of current opcode and value read from pc
@@ skipping 386 matching lines @@
 
   // The bound position, before this we cannot do instruction elimination.
   int last_bound_pos_;
 
   // source position information
   int current_position_;
   int current_statement_position_;
   int written_position_;
   int written_statement_position_;
 
+  bool thumb_mode_;
+
   // Code emission
   inline void CheckBuffer();
   void GrowBuffer();
   inline void emit(Instr x);
+  inline void emitThumb(ThumbInstr x);
+
+  void forceThumbMode();
+  void forceArmMode();
 
   // Instruction generation
   void addrmod1(Instr instr, Register rn, Register rd, const Operand& x);
   void addrmod2(Instr instr, Register rd, const MemOperand& x);
   void addrmod3(Instr instr, Register rd, const MemOperand& x);
   void addrmod4(Instr instr, Register rn, RegList rl);
   void addrmod5(Instr instr, CRegister crd, const MemOperand& x);
 
   // Labels
   void print(Label* L);
   void bind_to(Label* L, int pos);
   void link_to(Label* L, Label* appendix);
   void next(Label* L);
 
   // Record reloc info for current pc_
   void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
 
   friend class RegExpMacroAssemblerARM;
   friend class RelocInfo;
   friend class CodePatcher;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_ASSEMBLER_THUMB2_H_