X64: Implement debugger hooks.

src/arm/assembler-arm.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 413 matching lines @@
   // the branch/call instruction at pc.
   INLINE(static Address target_address_address_at(Address pc));
 
   // Read/Modify the code target address 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 instruction referring to the address of the call
   // target (ldr pc, [target addr in const pool]) and the return address
   static const int kTargetAddrToReturnAddrDist = sizeof(Instr);
+  // Distance between start of patched return sequence and the emitted address
+  // to jump to.
+  static const int kReturnAddrPatchPrefixSize = 1;
 
 
   // ---------------------------------------------------------------------------
   // Code generation
 
   // Insert the smallest number of nop instructions
   // possible to align the pc offset to a multiple
   // of m. m must be a power of 2 (>= 4).
   void Align(int m);
 
@@ skipping 335 matching lines @@
   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);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_ASSEMBLER_ARM_H_