Remove the weak list of array buffers

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 136 matching lines @@
 // easier if you can define it as part of the build environment.
 #if defined(V8_MAX_SEMISPACE_SIZE)
   max_semi_space_size_ = reserved_semispace_size_ = V8_MAX_SEMISPACE_SIZE;
 #endif
 
   // Ensure old_generation_size_ is a multiple of kPageSize.
   DCHECK(MB >= Page::kPageSize);
 
   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));
   // Put a dummy entry in the remembered pages so we can find the list the
   // minidump even if there are no real unmapped pages.
   RememberUnmappedPage(NULL, false);
 
   ClearObjectStats(true);
 }
 
@@ skipping 1119 matching lines @@
 
   if (FLAG_allocation_site_pretenuring) {
     EvaluateOldSpaceLocalPretenuring(size_of_objects_before_gc);
   }
 }
 
 
 void Heap::MarkCompactEpilogue() {
   gc_state_ = NOT_IN_GC;
 
+  ReapDeadArrayBuffers();

[Hannes Payer (out of office), 2015/04/29 11:48:21]

Please move this call to sweeping, since it frees up memory and therefore
logically belongs there.

+
   isolate_->counters()->objs_since_last_full()->Set(0);
 
   incremental_marking()->Epilogue();
 
   PreprocessStackTraces();
 }
 
 
 void Heap::MarkCompactPrologue() {
   // At any old GC clear the keyed lookup cache to enable collection of unused
@@ skipping 390 matching lines @@
     Object** start = &external_string_table_.old_space_strings_[0];
     Object** end = start + external_string_table_.old_space_strings_.length();
     for (Object** p = start; p < end; ++p) *p = updater_func(this, p);
   }
 
   UpdateNewSpaceReferencesInExternalStringTable(updater_func);
 }
 
 
 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,
-                                        false, NULL);
+  Object* head = VisitWeakList<Context>(this, native_contexts_list(), retainer);
   // Update the head of the list of contexts.
   set_native_contexts_list(head);
 }
 
 
-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);
+void Heap::RegisterLiveArrayBuffer(void* data, size_t length) {

[Hannes Payer (out of office), 2015/04/29 11:48:21]

What about calling this method RegisterNewArrayBuffer?

+  live_array_buffers_[data] = length;
+  reinterpret_cast<v8::Isolate*>(isolate_)
+      ->AdjustAmountOfExternalAllocatedMemory(length);
+}
 
-  // 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::UnregisterArrayBuffer(void* data) {
+  DCHECK(live_array_buffers_.count(data) > 0);
+  live_array_buffers_.erase(data);
+  not_yet_discovered_array_buffers_.erase(data);
+}
+
+
+void Heap::AddDiscoveredArrayBuffer(void* data) {

[Hannes Payer (out of office), 2015/04/29 11:48:21]

And since this method is not adding an array buffer, what about calling it
RegisterLiveArrayBuffer?

+  not_yet_discovered_array_buffers_.erase(data);
+}
+
+
+void Heap::ReapDeadArrayBuffers() {
+  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::TearDownArrayBuffers() {
-  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();
+  for (auto buffer = live_array_buffers_.begin();
+       buffer != live_array_buffers_.end(); ++buffer) {
+    isolate_->array_buffer_allocator()->Free(buffer->first, buffer->second);
   }
-  set_array_buffers_list(undefined);
+  live_array_buffers_.clear();
+  not_yet_discovered_array_buffers_.clear();
 }
 
 
 void Heap::ProcessAllocationSites(WeakObjectRetainer* retainer) {
-  Object* allocation_site_obj = VisitWeakList<AllocationSite>(
-      this, allocation_sites_list(), retainer, false, NULL);
+  Object* allocation_site_obj =
+      VisitWeakList<AllocationSite>(this, allocation_sites_list(), retainer);
   set_allocation_sites_list(allocation_site_obj);
 }
 
 
 void Heap::ResetAllAllocationSitesDependentCode(PretenureFlag flag) {
   DisallowHeapAllocation no_allocation_scope;
   Object* cur = allocation_sites_list();
   bool marked = false;
   while (cur->IsAllocationSite()) {
     AllocationSite* casted = AllocationSite::cast(cur);
@@ skipping 3624 matching lines @@
 bool Heap::CreateHeapObjects() {
   // Create initial maps.
   if (!CreateInitialMaps()) return false;
   CreateApiObjects();
 
   // Create initial objects
   CreateInitialObjects();
   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;
 }
 
 
 void Heap::SetStackLimits() {
   DCHECK(isolate_ != NULL);
   DCHECK(isolate_ == isolate());
   // On 64 bit machines, pointers are generally out of range of Smis.  We write
   // something that looks like an out of range Smi to the GC.
@@ skipping 992 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal