[Arm]: Enable use of extended out-of-line constant pool for Arm.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index aab918e231badf963241cf7e08c564180bdb5e86..e457ea9620a8a28e574a631e402be2a42469f4b1 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9674,15 +9674,23 @@ bool Map::EquivalentToForNormalization(Map* other,
 
 
 void ConstantPoolArray::ConstantPoolIterateBody(ObjectVisitor* v) {
-  ConstantPoolArray::Iterator code_iter(this, ConstantPoolArray::CODE_PTR);
-  while (!code_iter.is_finished()) {
-    v->VisitCodeEntry(reinterpret_cast<Address>(
-        RawFieldOfElementAt(code_iter.next_index())));
-  }
-
-  ConstantPoolArray::Iterator heap_iter(this, ConstantPoolArray::HEAP_PTR);
-  while (!heap_iter.is_finished()) {
-    v->VisitPointer(RawFieldOfElementAt(heap_iter.next_index()));
+  // Unfortunately the serializer relies on pointers being visited in-order,

[ulan, 2014/07/01 13:29:48]

Since we iterating first code pointers and the heap pointers, aren't we already
out-of-order? What does 'in-order' mean?

[rmcilroy, 2014/07/02 16:35:55]

In-order means that we visit the entries of the constant pool in order (e.g.,
from top to bottom in terms of the description in object.h:L3065-L3089), not the
actual locations pointed to by these entries.  Since the code entries come
first, we are doing this in-order here.

I've updated the comment to hopefully clarify this a bit.

[ulan, 2014/07/03 09:19:55]

Yes, the new comment makes it clear.

+  // so we have to iterate both the code and heap pointers in the small section
+  // before doing so in the extended section.
+  for (int s = 0; s <= final_section(); ++s) {
+    LayoutSection section = static_cast<LayoutSection>(s);
+    ConstantPoolArray::Iterator code_iter(
+        this, ConstantPoolArray::CODE_PTR, section);
+    while (!code_iter.is_finished()) {
+      v->VisitCodeEntry(reinterpret_cast<Address>(
+          RawFieldOfElementAt(code_iter.next_index())));
+    }
+
+    ConstantPoolArray::Iterator heap_iter(
+        this, ConstantPoolArray::HEAP_PTR, section);
+    while (!heap_iter.is_finished()) {
+      v->VisitPointer(RawFieldOfElementAt(heap_iter.next_index()));
+    }
   }
 }