The way reloc entries are visited by the ObjectVisitor is architecture...

src/assembler.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 20 matching lines @@
 // The original source code covered by the above license above has been
 // modified significantly by Google Inc.
 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 
 #ifndef V8_ASSEMBLER_H_
 #define V8_ASSEMBLER_H_
 
 #include "runtime.h"
 #include "top.h"
 #include "token.h"
+#include "objects.h"
 
 namespace v8 {
 namespace internal {
 
 
 // -----------------------------------------------------------------------------
 // Labels represent pc locations; they are typically jump or call targets.
 // After declaration, a label can be freely used to denote known or (yet)
 // unknown pc location. Assembler::bind() is used to bind a label to the
 // current pc. A label can be bound only once.
@@ skipping 141 matching lines @@
   // Read/modify the code target in the branch/call instruction
   // this relocation applies to;
   // can only be called if IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
   INLINE(Address target_address());
   INLINE(void set_target_address(Address target));
   INLINE(Object* target_object());
   INLINE(Handle<Object> target_object_handle(Assembler* origin));
   INLINE(Object** target_object_address());
   INLINE(void set_target_object(Object* target));
 
-  // Read the address of the word containing the target_address. Can only
-  // be called if IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY.
+  // Read the address of the word containing the target_address in an
+  // instruction stream.  What this means exactly is architecture-independent.
+  // The only architecture-independent user of this function is the serializer.
+  // The serializer uses it to find out how many raw bytes of instruction to
+  // output before the next target.  Architecture-independent code shouldn't
+  // dereference the pointer it gets back from this.
   INLINE(Address target_address_address());
+  // This indicates how much space a target takes up when deserializing a code
+  // stream.  For most architectures this is just the size of a pointer.  For
+  // an instruction like movw/movt where the target bits are mixed into the
+  // instruction bits the size of the target will be zero, indicating that the
+  // serializer should not step forwards in memory after a target is resolved
+  // and written.  In this case the target_address_address function above
+  // should return the end of the instructions to be patched, allowing the
+  // deserializer to deserialize the instructions as raw bytes and put them in
+  // place, ready to be patched with the target.
+  INLINE(int target_address_size());
 
   // Read/modify the reference in the instruction this relocation
   // applies to; can only be called if rmode_ is external_reference
   INLINE(Address* target_reference_address());
 
   // Read/modify the address of a call instruction. This is used to relocate
   // the break points where straight-line code is patched with a call
   // instruction.
   INLINE(Address call_address());
   INLINE(void set_call_address(Address target));
   INLINE(Object* call_object());
   INLINE(Object** call_object_address());
   INLINE(void set_call_object(Object* target));
 
+  inline void Visit(ObjectVisitor* v);
+
   // Patch the code with some other code.
   void PatchCode(byte* instructions, int instruction_count);
 
   // Patch the code with a call.
   void PatchCodeWithCall(Address target, int guard_bytes);
 
   // Check whether this return sequence has been patched
   // with a call to the debugger.
   INLINE(bool IsPatchedReturnSequence());
 
@@ skipping 310 matching lines @@
   unsigned int num_bits_set;
   for (num_bits_set = 0; x; x >>= 1) {
     num_bits_set += x & 1;
   }
   return num_bits_set;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_ASSEMBLER_H_