Object ID Ring with tests

runtime/vm/scavenger.cc

Index: runtime/vm/scavenger.cc
diff --git a/runtime/vm/scavenger.cc b/runtime/vm/scavenger.cc
index 8d6e4bf5be189dedb5a462cb1a672fb9afa992e9..6ee946374bed7f401b8318b6d232e2902ee34616 100644
--- a/runtime/vm/scavenger.cc
+++ b/runtime/vm/scavenger.cc
@@ -404,6 +404,17 @@ void Scavenger::IterateStoreBuffers(Isolate* isolate,
 }
 
 
+void Scavenger::IterateObjectIdTable(Isolate* isolate,
+                                     ScavengerVisitor* visitor) {
+  RawObject** table = heap_->get_object_id_ring_table();
+  const intptr_t table_size = heap_->get_object_id_ring_table_size();
+  if ((table == NULL) || (table_size <= 0)) {
+    return;
+  }
+  visitor->VisitPointers(&table[0], &table[table_size]);
+}
+
+
 void Scavenger::IterateRoots(Isolate* isolate,
                              ScavengerVisitor* visitor,
                              bool visit_prologue_weak_persistent_handles) {
@@ -413,6 +424,7 @@ void Scavenger::IterateRoots(Isolate* isolate,
                                StackFrameIterator::kDontValidateFrames);
   int64_t middle = OS::GetCurrentTimeMicros();
   IterateStoreBuffers(isolate, visitor);
+  IterateObjectIdTable(isolate, visitor);
   int64_t end = OS::GetCurrentTimeMicros();
   heap_->RecordTime(kVisitIsolateRoots, middle - start);
   heap_->RecordTime(kIterateStoreBuffers, end - middle);
@@ -590,6 +602,31 @@ void Scavenger::ProcessWeakTables() {
 }
 
 
+void Scavenger::ProcessObjectIdTable() {
+  RawObject** table = heap_->get_object_id_ring_table();

[Ivan Posva, 2013/07/10 01:10:13]

It would be better if we used a pointer visitor here instead of accessing the
internals of the ObjectIdRing directly.

[Cutch, 2013/07/10 17:23:10]

All accesses to the ring table via the scavenger and the marker are now done
using an ObjectPointerVisitor.

+  const intptr_t table_size = heap_->get_object_id_ring_table_size();
+  if ((table == NULL) || (table_size <= 0)) {
+    return;
+  }
+  for (intptr_t i = 0; i < table_size; i++) {
+    RawObject* raw_obj = table[i];
+    ASSERT(raw_obj->IsHeapObject());
+    if (raw_obj->IsOldObject()) {
+      // SKip old objects.
+      continue;
+    }
+    uword raw_addr = RawObject::ToAddr(raw_obj);
+    uword header = *reinterpret_cast<uword*>(raw_addr);
+    if (IsForwarding(header)) {
+      // The object has survived. Update its address in the table.
+      uword new_addr = ForwardedAddr(header);
+      raw_obj = RawObject::FromAddr(new_addr);
+      table[i] = raw_obj;
+    }
+  }
+}
+
+
 void Scavenger::VisitObjectPointers(ObjectPointerVisitor* visitor) const {
   uword cur = FirstObjectStart();
   while (cur < top_) {
@@ -642,6 +679,7 @@ void Scavenger::Scavenge(bool invoke_api_callbacks) {
   IterateWeakRoots(isolate, &weak_visitor, invoke_api_callbacks);
   visitor.Finalize();
   ProcessWeakTables();
+  ProcessObjectIdTable();
   int64_t end = OS::GetCurrentTimeMicros();
   heap_->RecordTime(kProcessToSpace, middle - start);
   heap_->RecordTime(kIterateWeaks, end - middle);