src/heap/embedder-tracing.cc

// Copyright 2016 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/embedder-tracing.h"

#include "src/base/logging.h"

namespace v8 {
namespace internal {

void LocalEmbedderHeapTracer::TracePrologue() {
  if (!InUse()) return;

  CHECK(cached_wrappers_to_trace_.empty());
  num_v8_marking_worklist_was_empty_ = 0;
  embedder_worklist_empty_ = false;
  remote_tracer_->TracePrologue();
}

void LocalEmbedderHeapTracer::TraceEpilogue() {
  if (!InUse()) return;

  CHECK(cached_wrappers_to_trace_.empty());
  remote_tracer_->TraceEpilogue();
}

void LocalEmbedderHeapTracer::EnterFinalPause() {
  if (!InUse()) return;

  remote_tracer_->EnterFinalPause(embedder_stack_state_);
  // Resetting to state unknown as there may be follow up garbage collections
  // triggered from callbacks that have a different stack state.
  embedder_stack_state_ = EmbedderHeapTracer::kUnknown;
}

bool LocalEmbedderHeapTracer::Trace(double deadline) {
  if (!InUse()) return true;

  DCHECK_EQ(0, NumberOfCachedWrappersToTrace());
  return remote_tracer_->AdvanceTracing(deadline);
}

bool LocalEmbedderHeapTracer::IsRemoteTracingDone() {
  return (InUse()) ? cached_wrappers_to_trace_.empty() &&
                         remote_tracer_->IsTracingDone()
                   : true;
}

void LocalEmbedderHeapTracer::RegisterWrappersWithRemoteTracer() {
  if (!InUse()) return;

  if (cached_wrappers_to_trace_.empty()) {
    return;
  }

  remote_tracer_->RegisterV8References(cached_wrappers_to_trace_);
  cached_wrappers_to_trace_.clear();
}

bool LocalEmbedderHeapTracer::RequiresImmediateWrapperProcessing() {
  const size_t kTooManyWrappers = 16000;
  return cached_wrappers_to_trace_.size() > kTooManyWrappers;
}

void LocalEmbedderHeapTracer::SetEmbedderStackStateForNextFinalization(
    EmbedderHeapTracer::EmbedderStackState stack_state) {
  if (!InUse()) return;

  embedder_stack_state_ = stack_state;
}

}  // namespace internal
}  // namespace v8