[heap] Record references in the new code objects in heap::CopyCode.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index d6a83346fab226b70ba9816222077bf99b14ffd9..e039633c2a0ef578e00db018330712d53eac713d 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -3373,6 +3373,12 @@ AllocationResult Heap::CopyCode(Code* code) {
   // We have to iterate over the object and process its pointers when black
   // allocation is on.
   incremental_marking()->IterateBlackObject(new_code);
+  // Record all references to embedded objects in the new code object.
+  for (RelocIterator it(new_code,

[Michael Lippautz, 2016/08/02 19:07:57]

That works, but ideally we would have fused visitor (together with the code in
IterateBlackObject). In the case that we copy a black object you need to visit
the reloc info twice, which is not ideal. Then again CopyCode might be rare
enough so that it does not matter.

Ulan, wdyt?

[ahaas, 2016/08/03 08:47:42]

I think that this would be an optimization that we should not do unless there
are actual performance reasons for it.

[ulan, 2016/08/03 10:59:32]

Yep, I would prefer decoding reloc info once. But for the sake of simplicity
let's keep it as it is unless benchmarks regress.

In any case, could you please extract new code into RecordWritesIntoCode
function?

+                        RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT));
+       !it.done(); it.next()) {
+    RecordWriteIntoCode(new_code, it.rinfo(), it.rinfo()->target_object());
+  }
   return new_code;
 }