X64: Implement debugger hooks.

src/ia32/assembler-ia32.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 420 matching lines @@
   // Assembler functions are invoked in between GetCode() calls.
   void GetCode(CodeDesc* desc);
 
   // Read/Modify the code target in the branch/call instruction at pc.
   inline static Address target_address_at(Address pc);
   inline static void set_target_address_at(Address pc, Address target);
 
   // Distance between the address of the code target in the call instruction
   // and the return address
   static const int kTargetAddrToReturnAddrDist = kPointerSize;
+  // Distance between start of patched return sequence and the emitted address
+  // to jump to.
+  static const int kReturnAddrPatchPrefixSize = 1;  // JMP imm32.
 
 
   // ---------------------------------------------------------------------------
   // Code generation
   //
   // - function names correspond one-to-one to ia32 instruction mnemonics
   // - unless specified otherwise, instructions operate on 32bit operands
   // - instructions on 8bit (byte) operands/registers have a trailing '_b'
   // - instructions on 16bit (word) operands/registers have a trailing '_w'
   // - naming conflicts with C++ keywords are resolved via a trailing '_'
@@ skipping 411 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_ASSEMBLER_IA32_H_