[heap] Create a thin wrapper around wrapper tracing in V8 to avoid misuse

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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/compilation-cache.h"
 #include "src/compiler-dispatcher/optimizing-compile-dispatcher.h"
 #include "src/conversions.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/global-handles.h"
 #include "src/heap/array-buffer-tracker-inl.h"
 #include "src/heap/code-stats.h"
+#include "src/heap/embedder-tracing.h"
 #include "src/heap/gc-idle-time-handler.h"
 #include "src/heap/gc-tracer.h"
 #include "src/heap/incremental-marking.h"
 #include "src/heap/mark-compact-inl.h"
 #include "src/heap/mark-compact.h"
 #include "src/heap/memory-reducer.h"
 #include "src/heap/object-stats.h"
 #include "src/heap/objects-visiting-inl.h"
 #include "src/heap/objects-visiting.h"
 #include "src/heap/remembered-set.h"
@@ skipping 115 matching lines @@
       ring_buffer_end_(0),
       promotion_queue_(this),
       configured_(false),
       current_gc_flags_(Heap::kNoGCFlags),
       current_gc_callback_flags_(GCCallbackFlags::kNoGCCallbackFlags),
       external_string_table_(this),
       gc_callbacks_depth_(0),
       deserialization_complete_(false),
       strong_roots_list_(NULL),
       heap_iterator_depth_(0),
-      embedder_heap_tracer_(nullptr),
+      local_embedder_heap_tracer_(nullptr),
       force_oom_(false),
       delay_sweeper_tasks_for_testing_(false) {
 // Allow build-time customization of the max semispace size. Building
 // V8 with snapshots and a non-default max semispace size is much
 // 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.
@@ skipping 1432 matching lines @@
   SetGCState(SCAVENGE);
 
   // Implements Cheney's copying algorithm
   LOG(isolate_, ResourceEvent("scavenge", "begin"));
 
   // Used for updating survived_since_last_expansion_ at function end.
   size_t survived_watermark = PromotedSpaceSizeOfObjects();
 
   scavenge_collector_->SelectScavengingVisitorsTable();
 
-  if (UsingEmbedderHeapTracer()) {
-    // Register found wrappers with embedder so it can add them to its marking
-    // deque and correctly manage the case when v8 scavenger collects the
-    // wrappers by either keeping wrappables alive, or cleaning marking deque.
-    RegisterWrappersWithEmbedderHeapTracer();
-  }
+  local_embedder_heap_tracer()->RegisterWrappersWithRemoteTracer();
 
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.
   new_space_->Flip();
   new_space_->ResetAllocationInfo();
 
   // We need to sweep newly copied objects which can be either in the
   // to space or promoted to the old generation.  For to-space
   // objects, we treat the bottom of the to space as a queue.  Newly
   // copied and unswept objects lie between a 'front' mark and the
@@ skipping 2548 matching lines @@
   if (ShouldReduceMemory() ||
       ((allocation_throughput != 0) &&
        (allocation_throughput < kLowAllocationThroughput))) {
     new_space_->Shrink();
     UncommitFromSpace();
   }
 }
 
 bool Heap::MarkingDequesAreEmpty() {
   return mark_compact_collector()->marking_deque()->IsEmpty() &&
-         (!UsingEmbedderHeapTracer() ||
-          (wrappers_to_trace() == 0 &&
-           embedder_heap_tracer()->NumberOfWrappersToTrace() == 0));
+         local_embedder_heap_tracer()->NumberOfWrappersToTrace() == 0;
 }
 
 void Heap::FinalizeIncrementalMarkingIfComplete(
     GarbageCollectionReason gc_reason) {
   if (incremental_marking()->IsMarking() &&
       (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
        (!incremental_marking()->finalize_marking_completed() &&
         MarkingDequesAreEmpty()))) {
     FinalizeIncrementalMarking(gc_reason);
   } else if (incremental_marking()->IsComplete() || MarkingDequesAreEmpty()) {
@@ skipping 1294 matching lines @@
   tracer_ = new GCTracer(this);
   scavenge_collector_ = new Scavenger(this);
   mark_compact_collector_ = new MarkCompactCollector(this);
   gc_idle_time_handler_ = new GCIdleTimeHandler();
   memory_reducer_ = new MemoryReducer(this);
   if (V8_UNLIKELY(FLAG_gc_stats)) {
     live_object_stats_ = new ObjectStats(this);
     dead_object_stats_ = new ObjectStats(this);
   }
   scavenge_job_ = new ScavengeJob();
+  local_embedder_heap_tracer_ = new LocalEmbedderHeapTracer();
 
   LOG(isolate_, IntPtrTEvent("heap-capacity", Capacity()));
   LOG(isolate_, IntPtrTEvent("heap-available", Available()));
 
   store_buffer()->SetUp();
 
   mark_compact_collector()->SetUp();
 
   idle_scavenge_observer_ = new IdleScavengeObserver(
       *this, ScavengeJob::kBytesAllocatedBeforeNextIdleTask);
@@ skipping 55 matching lines @@
       CHECK(p->NeverEvacuate());
     }
 #endif  // DEBUG
   }
 
   deserialization_complete_ = true;
 }
 
 void Heap::SetEmbedderHeapTracer(EmbedderHeapTracer* tracer) {
   DCHECK_EQ(gc_state_, HeapState::NOT_IN_GC);
-  embedder_heap_tracer_ = tracer;
-}
-
-void Heap::RegisterWrappersWithEmbedderHeapTracer() {
-  DCHECK(UsingEmbedderHeapTracer());
-  if (wrappers_to_trace_.empty()) {
-    return;
-  }
-  embedder_heap_tracer()->RegisterV8References(wrappers_to_trace_);
-  wrappers_to_trace_.clear();
+  local_embedder_heap_tracer()->SetRemoteTracer(tracer);
 }
 
 void Heap::TracePossibleWrapper(JSObject* js_object) {
   DCHECK(js_object->WasConstructedFromApiFunction());
   if (js_object->GetInternalFieldCount() >= 2 &&
       js_object->GetInternalField(0) &&
       js_object->GetInternalField(0) != undefined_value() &&
       js_object->GetInternalField(1) != undefined_value()) {
     DCHECK(reinterpret_cast<intptr_t>(js_object->GetInternalField(0)) % 2 == 0);
-    wrappers_to_trace_.push_back(std::pair<void*, void*>(
+    local_embedder_heap_tracer()->AddWrapperToTrace(std::pair<void*, void*>(
         reinterpret_cast<void*>(js_object->GetInternalField(0)),
         reinterpret_cast<void*>(js_object->GetInternalField(1))));
   }
 }
 
-bool Heap::RequiresImmediateWrapperProcessing() {
-  const size_t kTooManyWrappers = 16000;
-  return wrappers_to_trace_.size() > kTooManyWrappers;
-}
-
 void Heap::RegisterExternallyReferencedObject(Object** object) {
   HeapObject* heap_object = HeapObject::cast(*object);
   DCHECK(Contains(heap_object));
   if (FLAG_incremental_marking_wrappers && incremental_marking()->IsMarking()) {
     IncrementalMarking::MarkGrey(this, heap_object);
   } else {
     DCHECK(mark_compact_collector()->in_use());
     MarkBit mark_bit = ObjectMarking::MarkBitFrom(heap_object);
     mark_compact_collector()->MarkObject(heap_object, mark_bit);
   }
@@ skipping 56 matching lines @@
   if (live_object_stats_ != nullptr) {
     delete live_object_stats_;
     live_object_stats_ = nullptr;
   }
 
   if (dead_object_stats_ != nullptr) {
     delete dead_object_stats_;
     dead_object_stats_ = nullptr;
   }
 
+  delete local_embedder_heap_tracer_;
+  local_embedder_heap_tracer_ = nullptr;
+
   delete scavenge_job_;
   scavenge_job_ = nullptr;
 
   isolate_->global_handles()->TearDown();
 
   external_string_table_.TearDown();
 
   delete tracer_;
   tracer_ = nullptr;
 
@@ skipping 822 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8