Revert of Remove the weak list of array buffers

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index fac9535a6a6eeab7506cdaae951bd9051ddf5295..8d34738dae81757b9e5918875d6adf41cecf98bb 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -154,6 +154,8 @@
 
   memset(roots_, 0, sizeof(roots_[0]) * kRootListLength);
   set_native_contexts_list(NULL);
+  set_array_buffers_list(Smi::FromInt(0));
+  set_last_array_buffer_in_list(Smi::FromInt(0));
   set_allocation_sites_list(Smi::FromInt(0));
   set_encountered_weak_collections(Smi::FromInt(0));
   set_encountered_weak_cells(Smi::FromInt(0));
@@ -1703,67 +1705,64 @@
 
 
 void Heap::ProcessAllWeakReferences(WeakObjectRetainer* retainer) {
+  ProcessArrayBuffers(retainer, false);
   ProcessNativeContexts(retainer);
   ProcessAllocationSites(retainer);
 }
 
 
 void Heap::ProcessYoungWeakReferences(WeakObjectRetainer* retainer) {
+  ProcessArrayBuffers(retainer, true);
   ProcessNativeContexts(retainer);
 }
 
 
 void Heap::ProcessNativeContexts(WeakObjectRetainer* retainer) {
-  Object* head = VisitWeakList<Context>(this, native_contexts_list(), retainer);
+  Object* head = VisitWeakList<Context>(this, native_contexts_list(), retainer,
+                                        false, NULL);
   // Update the head of the list of contexts.
   set_native_contexts_list(head);
 }
 
 
-void Heap::RegisterNewArrayBuffer(void* data, size_t length) {
-  live_array_buffers_[data] = length;
-  reinterpret_cast<v8::Isolate*>(isolate_)
-      ->AdjustAmountOfExternalAllocatedMemory(length);
-}
-
-
-void Heap::UnregisterArrayBuffer(void* data) {
-  DCHECK(live_array_buffers_.count(data) > 0);
-  live_array_buffers_.erase(data);
-  not_yet_discovered_array_buffers_.erase(data);
-}
-
-
-void Heap::RegisterLiveArrayBuffer(void* data) {
-  not_yet_discovered_array_buffers_.erase(data);
-}
-
-
-void Heap::FreeDeadArrayBuffers() {
-  for (auto buffer = not_yet_discovered_array_buffers_.begin();
-       buffer != not_yet_discovered_array_buffers_.end(); ++buffer) {
-    isolate_->array_buffer_allocator()->Free(buffer->first, buffer->second);
-    // Don't use the API method here since this could trigger another GC.
-    amount_of_external_allocated_memory_ -= buffer->second;
-    live_array_buffers_.erase(buffer->first);
-  }
-  not_yet_discovered_array_buffers_ = live_array_buffers_;
+void Heap::ProcessArrayBuffers(WeakObjectRetainer* retainer,
+                               bool stop_after_young) {
+  Object* last_array_buffer = undefined_value();
+  Object* array_buffer_obj =
+      VisitWeakList<JSArrayBuffer>(this, array_buffers_list(), retainer,
+                                   stop_after_young, &last_array_buffer);
+  set_array_buffers_list(array_buffer_obj);
+  set_last_array_buffer_in_list(last_array_buffer);
+
+  // Verify invariant that young array buffers come before old array buffers
+  // in array buffers list if there was no promotion failure.
+  Object* undefined = undefined_value();
+  Object* next = array_buffers_list();
+  bool old_objects_recorded = false;
+  while (next != undefined) {
+    if (!old_objects_recorded) {
+      old_objects_recorded = !InNewSpace(next);
+    }
+    CHECK((InNewSpace(next) && !old_objects_recorded) || !InNewSpace(next));
+    next = JSArrayBuffer::cast(next)->weak_next();
+  }
 }
 
 
 void Heap::TearDownArrayBuffers() {
-  for (auto buffer = live_array_buffers_.begin();
-       buffer != live_array_buffers_.end(); ++buffer) {
-    isolate_->array_buffer_allocator()->Free(buffer->first, buffer->second);
-  }
-  live_array_buffers_.clear();
-  not_yet_discovered_array_buffers_.clear();
+  Object* undefined = undefined_value();
+  for (Object* o = array_buffers_list(); o != undefined;) {
+    JSArrayBuffer* buffer = JSArrayBuffer::cast(o);
+    Runtime::FreeArrayBuffer(isolate(), buffer);
+    o = buffer->weak_next();
+  }
+  set_array_buffers_list(undefined);
 }
 
 
 void Heap::ProcessAllocationSites(WeakObjectRetainer* retainer) {
-  Object* allocation_site_obj =
-      VisitWeakList<AllocationSite>(this, allocation_sites_list(), retainer);
+  Object* allocation_site_obj = VisitWeakList<AllocationSite>(
+      this, allocation_sites_list(), retainer, false, NULL);
   set_allocation_sites_list(allocation_site_obj);
 }
 
@@ -5408,6 +5407,8 @@
   CHECK_EQ(0u, gc_count_);
 
   set_native_contexts_list(undefined_value());
+  set_array_buffers_list(undefined_value());
+  set_last_array_buffer_in_list(undefined_value());
   set_allocation_sites_list(undefined_value());
   return true;
 }