[heap] Increase test coverage for embedder tracing

The tests illustrate the use of v8::EmbedderHeapTracer.

Bug: v8:7176
Change-Id: Ic383c968691fddb0ec96d66cb33ee42b9c304a75
Reviewed-on: https://chromium-review.googlesource.com/811924
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49934}

src/factory.cc

@@ -1976,6 +1976,18 @@ void Factory::NewJSArrayStorage(Handle<JSArray> array,
   array->set_length(Smi::FromInt(length));
 }
 
+Handle<JSWeakMap> Factory::NewJSWeakMap() {
+  Context* native_context = isolate()->raw_native_context();
+  Handle<Map> map(native_context->js_weak_map_fun()->initial_map());
+  Handle<JSWeakMap> weakmap(JSWeakMap::cast(*NewJSObjectFromMap(map)));
+  {
+    // Do not leak handles for the hash table, it would make entries strong.
+    HandleScope scope(isolate());
+    JSWeakCollection::Initialize(weakmap, isolate());
+  }
+  return weakmap;
+}
+
 Handle<JSModuleNamespace> Factory::NewJSModuleNamespace() {
   Handle<Map> map = isolate()->js_module_namespace_map();
   Handle<JSModuleNamespace> module_namespace(

src/factory.h

@@ -36,6 +36,7 @@ class JSMapIterator;
 class JSModuleNamespace;
 class JSSet;
 class JSSetIterator;
+class JSWeakMap;
 class NewFunctionArgs;
 struct SourceRange;
 class PreParsedScopeData;
@@ -555,6 +556,8 @@ class V8_EXPORT_PRIVATE Factory final {
       int capacity,
       ArrayStorageAllocationMode mode = DONT_INITIALIZE_ARRAY_ELEMENTS);
 
+  Handle<JSWeakMap> NewJSWeakMap();
+
   Handle<JSGeneratorObject> NewJSGeneratorObject(Handle<JSFunction> function);
 
   Handle<JSModuleNamespace> NewJSModuleNamespace();

test/cctest/BUILD.gn

@@ -103,6 +103,7 @@ v8_source_set("cctest_sources") {
     "heap/test-array-buffer-tracker.cc",
     "heap/test-compaction.cc",
     "heap/test-concurrent-marking.cc",
+    "heap/test-embedder-tracing.cc",
     "heap/test-heap.cc",
     "heap/test-incremental-marking.cc",
     "heap/test-invalidated-slots.cc",

test/cctest/cctest.gyp

@@ -93,6 +93,7 @@
       'heap/test-array-buffer-tracker.cc',
       'heap/test-compaction.cc',
       'heap/test-concurrent-marking.cc',
+      'heap/test-embedder-tracing.cc',
       'heap/test-heap.cc',
       'heap/test-incremental-marking.cc',
       'heap/test-invalidated-slots.cc',

test/cctest/cctest.status

@@ -88,6 +88,9 @@
   # BUG(2340). Preprocessing stack traces is disabled at the moment.
   'test-heap/PreprocessStackTrace': [FAIL],
 
+  # BUG(7176). Embedder heap tracer doesn't support finalizers.
+  'test-embedder-tracing/TracingInRevivedSubgraph': [FAIL],
+
   # BUG(4333). Function name inferrer does not work for ES6 clases.
   'test-func-name-inference/UpperCaseClass': [FAIL],
   'test-func-name-inference/LowerCaseClass': [FAIL],

test/cctest/heap/test-embedder-tracing.cc

+// Copyright 2017 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 "include/v8.h"
+#include "src/api.h"
+#include "src/objects-inl.h"
+#include "src/objects/module.h"
+#include "src/objects/script.h"
+#include "src/objects/shared-function-info.h"
+#include "test/cctest/cctest.h"
+
+namespace v8 {
+namespace internal {
+namespace heap {
+
+namespace {
+
+v8::Local<v8::Object> ConstructTraceableJSApiObject(
+    v8::Local<v8::Context> context, void* first_field, void* second_field) {
+  v8::EscapableHandleScope scope(context->GetIsolate());
+  v8::Local<v8::FunctionTemplate> function_t =
+      v8::FunctionTemplate::New(context->GetIsolate());
+  v8::Local<v8::ObjectTemplate> instance_t = function_t->InstanceTemplate();
+  instance_t->SetInternalFieldCount(2);
+  v8::Local<v8::Function> function =
+      function_t->GetFunction(context).ToLocalChecked();
+  v8::Local<v8::Object> instance =
+      function->NewInstance(context).ToLocalChecked();
+  instance->SetAlignedPointerInInternalField(0, first_field);
+  instance->SetAlignedPointerInInternalField(1, second_field);
+  CHECK(!instance.IsEmpty());
+  i::Handle<i::JSReceiver> js_obj = v8::Utils::OpenHandle(*instance);
+  CHECK_EQ(i::JS_API_OBJECT_TYPE, js_obj->map()->instance_type());
+  return scope.Escape(instance);
+}
+
+class TestEmbedderHeapTracer final : public v8::EmbedderHeapTracer {
+ public:
+  explicit TestEmbedderHeapTracer(v8::Isolate* isolate) : isolate_(isolate) {}
+
+  void RegisterV8References(
+      const std::vector<std::pair<void*, void*>>& embedder_fields) final {
+    registered_from_v8_.insert(registered_from_v8_.end(),
+                               embedder_fields.begin(), embedder_fields.end());
+  }
+
+  void AddReferenceForTracing(v8::Persistent<v8::Object>* persistent) {
+    to_register_with_v8_.push_back(persistent);
+  }
+
+  bool AdvanceTracing(double deadline_in_ms,
+                      AdvanceTracingActions actions) final {
+    for (auto persistent : to_register_with_v8_) {
+      persistent->RegisterExternalReference(isolate_);
+    }
+    to_register_with_v8_.clear();
+    return false;
+  }
+
+  void TracePrologue() final {}
+  void TraceEpilogue() final {}
+  void AbortTracing() final {}
+  void EnterFinalPause() final {}
+
+  bool IsRegisteredFromV8(void* first_field) const {
+    for (auto pair : registered_from_v8_) {
+      if (pair.first == first_field) return true;
+    }
+    return false;
+  }
+
+ private:
+  v8::Isolate* const isolate_;
+  std::vector<std::pair<void*, void*>> registered_from_v8_;
+  std::vector<v8::Persistent<v8::Object>*> to_register_with_v8_;
+};
+
+}  // namespace
+
+TEST(V8RegisteringEmbedderReference) {
+  // Tests that wrappers are properly registered with the embedder heap
+  // tracer.
+  ManualGCScope manual_gc;
+  CcTest::InitializeVM();
+  v8::Isolate* isolate = CcTest::isolate();
+  TestEmbedderHeapTracer tracer(isolate);
+  isolate->SetEmbedderHeapTracer(&tracer);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+
+  void* first_field = reinterpret_cast<void*>(0x2);
+  v8::Local<v8::Object> api_object =
+      ConstructTraceableJSApiObject(context, first_field, nullptr);
+  CHECK(!api_object.IsEmpty());
+  CcTest::CollectGarbage(i::OLD_SPACE);
+  CHECK(tracer.IsRegisteredFromV8(first_field));
+}
+
+TEST(EmbedderRegisteringV8Reference) {
+  // Tests that references that are registered by the embedder heap tracer are
+  // considered live by V8.
+  ManualGCScope manual_gc;
+  CcTest::InitializeVM();
+  v8::Isolate* isolate = CcTest::isolate();
+  TestEmbedderHeapTracer tracer(isolate);
+  isolate->SetEmbedderHeapTracer(&tracer);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+
+  v8::Persistent<v8::Object> g;
+  {
+    v8::HandleScope inner_scope(isolate);
+    v8::Local<v8::Object> o =
+        v8::Local<v8::Object>::New(isolate, v8::Object::New(isolate));
+    g.Reset(isolate, o);
+    g.SetWeak();
+  }
+  tracer.AddReferenceForTracing(&g);
+  CcTest::CollectGarbage(i::OLD_SPACE);
+  CHECK(!g.IsEmpty());
+}
+
+namespace {
+
+void ResurrectingFinalizer(
+    const v8::WeakCallbackInfo<v8::Global<v8::Object>>& data) {
+  data.GetParameter()->ClearWeak();
+}
+
+}  // namespace
+
+TEST(TracingInRevivedSubgraph) {
+  // Tests that wrappers are traced when they are contained with in a subgraph
+  // that is revived by a finalizer.
+  ManualGCScope manual_gc;
+  CcTest::InitializeVM();
+  v8::Isolate* isolate = CcTest::isolate();
+  TestEmbedderHeapTracer tracer(isolate);
+  isolate->SetEmbedderHeapTracer(&tracer);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+
+  v8::Global<v8::Object> g;
+  void* first_field = reinterpret_cast<void*>(0x4);
+  {
+    v8::HandleScope inner_scope(isolate);
+    v8::Local<v8::Object> api_object =
+        ConstructTraceableJSApiObject(context, first_field, nullptr);
+    CHECK(!api_object.IsEmpty());
+    v8::Local<v8::Object> o =
+        v8::Local<v8::Object>::New(isolate, v8::Object::New(isolate));
+    o->Set(context, v8_str("link"), api_object).FromJust();
+    g.Reset(isolate, o);
+    g.SetWeak(&g, ResurrectingFinalizer, v8::WeakCallbackType::kFinalizer);
+  }
+  CcTest::CollectGarbage(i::OLD_SPACE);
+  CHECK(tracer.IsRegisteredFromV8(first_field));
+}
+
+TEST(TracingInEphemerons) {
+  // Tests that wrappers that are part of ephemerons are traced.
+  ManualGCScope manual_gc;
+  CcTest::InitializeVM();
+  v8::Isolate* isolate = CcTest::isolate();
+  TestEmbedderHeapTracer tracer(isolate);
+  isolate->SetEmbedderHeapTracer(&tracer);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+
+  v8::Local<v8::Object> key =
+      v8::Local<v8::Object>::New(isolate, v8::Object::New(isolate));
+  void* first_field = reinterpret_cast<void*>(0x8);
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  Handle<JSWeakMap> weak_map = i_isolate->factory()->NewJSWeakMap();
+  {
+    v8::HandleScope inner_scope(isolate);
+    v8::Local<v8::Object> api_object =
+        ConstructTraceableJSApiObject(context, first_field, nullptr);
+    CHECK(!api_object.IsEmpty());
+    Handle<JSObject> js_key =
+        handle(JSObject::cast(*v8::Utils::OpenHandle(*key)));
+    Handle<JSReceiver> js_api_object = v8::Utils::OpenHandle(*api_object);
+    int32_t hash = js_key->GetOrCreateHash(i_isolate)->value();
+    JSWeakCollection::Set(weak_map, js_key, js_api_object, hash);
+  }
+  CcTest::CollectGarbage(i::OLD_SPACE);
+  CHECK(tracer.IsRegisteredFromV8(first_field));
+}
+
+}  // namespace heap
+}  // namespace internal
+}  // namespace v8

test/cctest/test-weakmaps.cc

@@ -42,21 +42,6 @@ static Isolate* GetIsolateFrom(LocalContext* context) {
   return reinterpret_cast<Isolate*>((*context)->GetIsolate());
 }
 
-
-static Handle<JSWeakMap> AllocateJSWeakMap(Isolate* isolate) {
-  Handle<Map> map =
-      isolate->factory()->NewMap(JS_WEAK_MAP_TYPE, JSWeakMap::kSize);
-  Handle<JSObject> weakmap_obj = isolate->factory()->NewJSObjectFromMap(map);
-  Handle<JSWeakMap> weakmap(JSWeakMap::cast(*weakmap_obj));
-  // Do not leak handles for the hash table, it would make entries strong.
-  {
-    HandleScope scope(isolate);
-    Handle<ObjectHashTable> table = ObjectHashTable::New(isolate, 1);
-    weakmap->set_table(*table);
-  }
-  return weakmap;
-}
-
 static int NumberOfWeakCalls = 0;
 static void WeakPointerCallback(const v8::WeakCallbackInfo<void>& data) {
   std::pair<v8::Persistent<v8::Value>*, int>* p =
@@ -74,7 +59,7 @@ TEST(Weakness) {
   Isolate* isolate = GetIsolateFrom(&context);
   Factory* factory = isolate->factory();
   HandleScope scope(isolate);
-  Handle<JSWeakMap> weakmap = AllocateJSWeakMap(isolate);
+  Handle<JSWeakMap> weakmap = isolate->factory()->NewJSWeakMap();
   GlobalHandles* global_handles = isolate->global_handles();
 
   // Keep global reference to the key.
@@ -127,7 +112,7 @@ TEST(Shrinking) {
   Isolate* isolate = GetIsolateFrom(&context);
   Factory* factory = isolate->factory();
   HandleScope scope(isolate);
-  Handle<JSWeakMap> weakmap = AllocateJSWeakMap(isolate);
+  Handle<JSWeakMap> weakmap = isolate->factory()->NewJSWeakMap();
 
   // Check initial capacity.
   CHECK_EQ(32, ObjectHashTable::cast(weakmap->table())->Capacity());
@@ -174,7 +159,7 @@ TEST(Regress2060a) {
   Handle<JSFunction> function =
       factory->NewFunctionForTest(factory->function_string());
   Handle<JSObject> key = factory->NewJSObject(function);
-  Handle<JSWeakMap> weakmap = AllocateJSWeakMap(isolate);
+  Handle<JSWeakMap> weakmap = isolate->factory()->NewJSWeakMap();
 
   // Start second old-space page so that values land on evacuation candidate.
   Page* first_page = heap->old_space()->anchor()->next_page();
@@ -226,7 +211,7 @@ TEST(Regress2060b) {
     CHECK(!heap->InNewSpace(*keys[i]));
     CHECK(!first_page->Contains(keys[i]->address()));
   }
-  Handle<JSWeakMap> weakmap = AllocateJSWeakMap(isolate);
+  Handle<JSWeakMap> weakmap = isolate->factory()->NewJSWeakMap();
   for (int i = 0; i < 32; i++) {
     Handle<Smi> smi(Smi::FromInt(i), isolate);
     int32_t hash = keys[i]->GetOrCreateHash(isolate)->value();
@@ -250,7 +235,7 @@ TEST(Regress399527) {
   Heap* heap = isolate->heap();
   {
     HandleScope scope(isolate);
-    AllocateJSWeakMap(isolate);
+    isolate->factory()->NewJSWeakMap();
     heap::SimulateIncrementalMarking(heap);
   }
   // The weak map is marked black here but leaving the handle scope will make