Add initial version of retainers heap profile.

src/heap-profiler.cc

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "heap-profiler.h"
+#include "string-stream.h"
+
+namespace v8 {
+namespace internal {
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+namespace {
+
+// JSStatsHelper provides service functions for examining
+// JS objects allocated on heap. It is run during garbage
+// collection cycle, thus it doesn't need to use handles.
+class JSStatsHelper {
+ public:
+  static int CalculateNetworkSize(JSObject* obj);
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSStatsHelper);
+};
+
+
+int JSStatsHelper::CalculateNetworkSize(JSObject* obj) {
+  int size = obj->Size();
+  // If 'properties' and 'elements' are non-empty (thus, non-shared),
+  // take their size into account.
+  if (FixedArray::cast(obj->properties())->length() != 0) {
+    size += obj->properties()->Size();
+  }
+  if (FixedArray::cast(obj->elements())->length() != 0) {
+    size += obj->elements()->Size();
+  }
+  return size;
+}
+
+
+// A helper class for recording back references.
+class ReferencesExtractor : public ObjectVisitor {
+ public:
+  ReferencesExtractor(
+      const JSObjectsCluster& cluster, RetainerHeapProfile* profile)
+      : cluster_(cluster),
+        profile_(profile),
+        insideArray_(false) {
+  }
+
+  void VisitPointer(Object** o) {
+    if ((*o)->IsJSObject() || (*o)->IsString()) {
+      profile_->StoreReference(cluster_, *o);
+    } else if ((*o)->IsFixedArray() && !insideArray_) {
+      // Traverse one level deep for data members that are fixed arrays.
+      // This covers the case of 'elements' and 'properties' of JSObject,
+      // and function contexts.
+      insideArray_ = true;
+      FixedArray::cast(*o)->Iterate(this);
+      insideArray_ = false;
+    }
+  }
+
+  void VisitPointers(Object** start, Object** end) {
+    for (Object** p = start; p < end; p++) VisitPointer(p);
+  }
+
+ private:
+  const JSObjectsCluster& cluster_;
+  RetainerHeapProfile* profile_;
+  bool insideArray_;
+};
+
+
+// A printer interface implementation for the Retainers profile.
+class RetainersPrinter : public RetainerHeapProfile::Printer {
+ public:
+  void PrintRetainers(const StringStream& retainers) {
+    LOG(HeapSampleJSRetainersEvent(*(retainers.ToCString())));
+  }
+};
+
+}  // namespace
+
+
+const ConstructorHeapProfile::TreeConfig::Key
+    ConstructorHeapProfile::TreeConfig::kNoKey = NULL;
+const ConstructorHeapProfile::TreeConfig::Value
+    ConstructorHeapProfile::TreeConfig::kNoValue;
+
+
+ConstructorHeapProfile::ConstructorHeapProfile()
+    : zscope_(DELETE_ON_EXIT) {
+}
+
+
+void ConstructorHeapProfile::Call(String* name,
+                                const NumberAndSizeInfo& number_and_size) {
+  ASSERT(name != NULL);
+  SmartPointer<char> s_name(
+      name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL));
+  LOG(HeapSampleJSConstructorEvent(*s_name,
+                                   number_and_size.number(),
+                                   number_and_size.bytes()));
+}
+
+
+void ConstructorHeapProfile::CollectStats(HeapObject* obj) {
+  String* constructor = NULL;
+  int size;
+  if (obj->IsString()) {
+    constructor = Heap::String_symbol();
+    size = obj->Size();
+  } else if (obj->IsJSObject()) {
+    JSObject* js_obj = JSObject::cast(obj);
+    constructor = js_obj->constructor_name();
+    size = JSStatsHelper::CalculateNetworkSize(js_obj);
+  } else {
+    return;
+  }
+
+  JSObjectsInfoTree::Locator loc;
+  if (!js_objects_info_tree_.Find(constructor, &loc)) {
+    js_objects_info_tree_.Insert(constructor, &loc);
+  }
+  NumberAndSizeInfo number_and_size = loc.value();
+  number_and_size.increment_number(1);
+  number_and_size.increment_bytes(size);
+  loc.set_value(number_and_size);
+}
+
+
+void ConstructorHeapProfile::PrintStats() {
+  js_objects_info_tree_.ForEach(this);
+}
+
+
+void JSObjectsCluster::Print(StringStream* accumulator) const {
+  ASSERT(!is_null());
+  if (constructor_ == FromSpecialCase(ROOTS)) {
+    accumulator->Add("(roots)");
+  } else if (constructor_ == FromSpecialCase(GLOBAL_PROPERTY)) {
+    accumulator->Add("(global property)");
+  } else {
+    SmartPointer<char> s_name(
+        constructor_->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL));
+    accumulator->Add("%s", (*s_name)[0] != '\0' ? *s_name : "(anonymous)");
+    if (instance_ != NULL) {
+      accumulator->Add(":%p", static_cast<void*>(instance_));
+    }
+  }
+}
+
+
+void JSObjectsCluster::DebugPrint(StringStream* accumulator) const {
+  if (!is_null()) {
+    Print(accumulator);
+  } else {
+    accumulator->Add("(null cluster)");
+  }
+}
+
+
+inline ClustersCoarser::ClusterBackRefs::ClusterBackRefs(
+    const JSObjectsCluster& cluster_)
+    : cluster(cluster_), refs(INITIAL_BACKREFS_LIST_CAPACITY) {
+}
+
+
+inline ClustersCoarser::ClusterBackRefs::ClusterBackRefs(
+    const ClustersCoarser::ClusterBackRefs::ClusterBackRefs& src)
+    : cluster(src.cluster), refs(src.refs.capacity()) {
+  refs.AddAll(src.refs);
+}
+
+
+inline ClustersCoarser::ClusterBackRefs::ClusterBackRefs&
+ClustersCoarser::ClusterBackRefs::operator=(
+    const ClustersCoarser::ClusterBackRefs::ClusterBackRefs& src) {
+  if (this == &src) return *this;
+  cluster = src.cluster;
+  refs.Clear();
+  refs.AddAll(src.refs);
+  return *this;
+}
+
+
+inline int ClustersCoarser::ClusterBackRefs::Compare(
+    const ClustersCoarser::ClusterBackRefs::ClusterBackRefs& a,
+    const ClustersCoarser::ClusterBackRefs::ClusterBackRefs& b) {
+  int cmp = JSObjectsCluster::CompareConstructors(a.cluster, b.cluster);
+  if (cmp != 0) return cmp;
+  if (a.refs.length() < b.refs.length()) return -1;
+  if (a.refs.length() > b.refs.length()) return 1;
+  for (int i = 0; i < a.refs.length(); ++i) {
+    int cmp = JSObjectsCluster::Compare(a.refs[i], b.refs[i]);
+    if (cmp != 0) return cmp;
+  }
+  return 0;
+}
+
+
+ClustersCoarser::ClustersCoarser()
+  : zscope_(DELETE_ON_EXIT),
+    simList_(ClustersCoarser::INITIAL_SIMILARITY_LIST_CAPACITY),
+    currentPair_(NULL) {
+}
+
+
+void ClustersCoarser::Call(
+    const JSObjectsCluster& cluster, JSObjectsClusterTree* tree) {
+  if (tree != NULL) {
+    // First level of retainer graph.
+    if (!cluster.can_be_coarsed()) return;
+    ClusterBackRefs pair(cluster);
+    ASSERT(currentPair_ == NULL);
+    currentPair_ = &pair;
+    currentSet_ = new JSObjectsClusterTree();
+    tree->ForEach(this);
+    simList_.Add(pair);
+    currentPair_ = NULL;
+    currentSet_ = NULL;
+  } else {
+    // Second level of retainer graph.
+    ASSERT(currentPair_ != NULL);
+    ASSERT(currentSet_ != NULL);
+    JSObjectsCluster eq = GetCoarseEquivalent(cluster);
+    JSObjectsClusterTree::Locator loc;
+    if (!eq.is_null()) {
+      if (currentSet_->Find(eq, &loc)) return;
+      currentPair_->refs.Add(eq);
+      currentSet_->Insert(eq, &loc);
+    } else {
+      currentPair_->refs.Add(cluster);
+    }
+  }
+}
+
+
+void ClustersCoarser::Process(JSObjectsClusterTree* tree) {
+  int last_eq_clusters = -1;
+  for (int i = 0; i < MAX_PASSES_COUNT; ++i) {
+    simList_.Clear();
+    const int curr_eq_clusters = DoProcess(tree);
+    // If no new cluster equivalents discovered, abort processing.
+    if (last_eq_clusters == curr_eq_clusters) break;
+    last_eq_clusters = curr_eq_clusters;
+  }
+}
+
+
+int ClustersCoarser::DoProcess(JSObjectsClusterTree* tree) {
+  tree->ForEach(this);
+  // To sort similarity list properly, references list of a cluster is
+  // required to be sorted, thus 'O1 <- A, B' and 'O2 <- B, A' would
+  // be considered equivalent. But we don't sort them explicitly
+  // because we know that they come from a splay tree traversal, so
+  // they are already sorted.
+  simList_.Sort(ClusterBackRefsCmp);
+  return FillEqualityTree();
+}
+
+
+JSObjectsCluster ClustersCoarser::GetCoarseEquivalent(
+    const JSObjectsCluster& cluster) {
+  if (!cluster.can_be_coarsed()) return JSObjectsCluster();
+  EqualityTree::Locator loc;
+  return eqTree_.Find(cluster, &loc) ? loc.value() : JSObjectsCluster();
+}
+
+
+bool ClustersCoarser::HasAnEquivalent(const JSObjectsCluster& cluster) {
+  // Return true for coarsible clusters that have a non-identical equivalent.
+  return cluster.can_be_coarsed() &&
+      JSObjectsCluster::Compare(cluster, GetCoarseEquivalent(cluster)) != 0;
+}
+
+
+int ClustersCoarser::FillEqualityTree() {
+  int eqClustersCount = 0;
+  int eqTo = 0;
+  bool firstAdded = false;
+  for (int i = 1; i < simList_.length(); ++i) {
+    if (ClusterBackRefs::Compare(simList_[i], simList_[eqTo]) == 0) {
+      EqualityTree::Locator loc;
+      if (!firstAdded) {
+        // Add self-equivalence, if we have more than one item in this
+        // equivalence class.
+        eqTree_.Insert(simList_[eqTo].cluster, &loc);
+        loc.set_value(simList_[eqTo].cluster);
+        firstAdded = true;
+      }
+      eqTree_.Insert(simList_[i].cluster, &loc);
+      loc.set_value(simList_[eqTo].cluster);
+      ++eqClustersCount;
+    } else {
+      eqTo = i;
+      firstAdded = false;
+    }
+  }
+  return eqClustersCount;
+}
+
+
+const JSObjectsCluster ClustersCoarser::ClusterEqualityConfig::kNoKey;
+const JSObjectsCluster ClustersCoarser::ClusterEqualityConfig::kNoValue;
+const JSObjectsClusterTreeConfig::Key JSObjectsClusterTreeConfig::kNoKey;
+const JSObjectsClusterTreeConfig::Value JSObjectsClusterTreeConfig::kNoValue =
+    NULL;
+
+
+RetainerHeapProfile::RetainerHeapProfile()
+    : zscope_(DELETE_ON_EXIT),
+      coarse_cluster_tree_(NULL),
+      retainers_printed_(0),
+      current_printer_(NULL),
+      current_stream_(NULL) {
+  ReferencesExtractor extractor(
+      JSObjectsCluster(JSObjectsCluster::ROOTS), this);
+  Heap::IterateRoots(&extractor);
+}
+
+
+JSObjectsCluster RetainerHeapProfile::Clusterize(Object* obj) {
+  if (obj->IsJSObject()) {
+    String* constructor = JSObject::cast(obj)->constructor_name();
+    // Differentiate Object and Array instances.
+    if (constructor == Heap::Object_symbol() ||
+        constructor == Heap::Array_symbol()) {
+      return JSObjectsCluster(constructor, obj);
+    } else {
+      return JSObjectsCluster(constructor);
+    }
+  } else if (obj->IsString()) {
+    return JSObjectsCluster(Heap::String_symbol());
+  } else {
+    UNREACHABLE();
+    return JSObjectsCluster();
+  }
+}
+
+
+void RetainerHeapProfile::StoreReference(
+    const JSObjectsCluster& cluster,
+    Object* ref) {
+  JSObjectsCluster ref_cluster = Clusterize(ref);
+  JSObjectsClusterTree::Locator ref_loc;
+  if (retainers_tree_.Insert(ref_cluster, &ref_loc)) {
+    ref_loc.set_value(new JSObjectsClusterTree());
+  }
+  JSObjectsClusterTree* referencedBy = ref_loc.value();
+  JSObjectsClusterTree::Locator obj_loc;
+  referencedBy->Insert(cluster, &obj_loc);
+}
+
+
+void RetainerHeapProfile::CollectStats(HeapObject* obj) {
+  if (obj->IsJSObject()) {
+    const JSObjectsCluster cluster = Clusterize(JSObject::cast(obj));
+    ReferencesExtractor extractor(cluster, this);
+    obj->Iterate(&extractor);
+  } else if (obj->IsJSGlobalPropertyCell()) {
+    ReferencesExtractor extractor(
+        JSObjectsCluster(JSObjectsCluster::GLOBAL_PROPERTY), this);
+    obj->Iterate(&extractor);
+  }
+}
+
+
+void RetainerHeapProfile::DebugPrintStats(
+    RetainerHeapProfile::Printer* printer) {
+  coarser_.Process(&retainers_tree_);
+  ASSERT(current_printer_ == NULL);
+  current_printer_ = printer;
+  retainers_tree_.ForEach(this);
+  current_printer_ = NULL;
+}
+
+
+void RetainerHeapProfile::PrintStats() {
+  RetainersPrinter printer;
+  DebugPrintStats(&printer);
+}
+
+
+void RetainerHeapProfile::Call(
+    const JSObjectsCluster& cluster,
+    JSObjectsClusterTree* tree) {
+  ASSERT(current_printer_ != NULL);
+  if (tree != NULL) {
+    // First level of retainer graph.
+    if (coarser_.HasAnEquivalent(cluster)) return;
+    ASSERT(current_stream_ == NULL);
+    HeapStringAllocator allocator;
+    StringStream stream(&allocator);
+    current_stream_ = &stream;
+    cluster.Print(current_stream_);
+    ASSERT(coarse_cluster_tree_ == NULL);
+    coarse_cluster_tree_ = new JSObjectsClusterTree();
+    retainers_printed_ = 0;
+    tree->ForEach(this);
+    coarse_cluster_tree_ = NULL;
+    current_printer_->PrintRetainers(stream);
+    current_stream_ = NULL;
+  } else {
+    // Second level of retainer graph.
+    ASSERT(coarse_cluster_tree_ != NULL);
+    ASSERT(current_stream_ != NULL);
+    if (retainers_printed_ >= MAX_RETAINERS_TO_PRINT) {
+      if (retainers_printed_ == MAX_RETAINERS_TO_PRINT) {
+        // TODO(mnaganov): Print the exact count.
+        current_stream_->Add(",...");
+        ++retainers_printed_;  // avoid printing ellipsis next time.
+      }
+      return;
+    }
+    JSObjectsCluster eq = coarser_.GetCoarseEquivalent(cluster);
+    if (eq.is_null()) {
+      current_stream_->Put(',');
+      cluster.Print(current_stream_);
+      ++retainers_printed_;
+    } else {
+      JSObjectsClusterTree::Locator loc;
+      if (!coarse_cluster_tree_->Find(eq, &loc)) {
+        coarse_cluster_tree_->Insert(eq, &loc);
+        current_stream_->Put(',');
+        eq.Print(current_stream_);
+        ++retainers_printed_;
+      }
+    }
+  }
+}
+
+
+//
+// HeapProfiler class implementation.
+//
+void HeapProfiler::CollectStats(HeapObject* obj, HistogramInfo* info) {
+  InstanceType type = obj->map()->instance_type();
+  ASSERT(0 <= type && type <= LAST_TYPE);
+  info[type].increment_number(1);
+  info[type].increment_bytes(obj->Size());
+}
+
+
+void HeapProfiler::WriteSample() {
+  LOG(HeapSampleBeginEvent("Heap", "allocated"));
+  LOG(HeapSampleStats(
+      "Heap", "allocated", Heap::Capacity(), Heap::SizeOfObjects()));
+
+  HistogramInfo info[LAST_TYPE+1];
+#define DEF_TYPE_NAME(name) info[name].set_name(#name);
+  INSTANCE_TYPE_LIST(DEF_TYPE_NAME)
+#undef DEF_TYPE_NAME
+
+  ConstructorHeapProfile js_cons_profile;
+  RetainerHeapProfile js_retainer_profile;
+  HeapIterator iterator;
+  while (iterator.has_next()) {
+    HeapObject* obj = iterator.next();
+    CollectStats(obj, info);
+    js_cons_profile.CollectStats(obj);
+    js_retainer_profile.CollectStats(obj);
+  }
+
+  // Lump all the string types together.
+  int string_number = 0;
+  int string_bytes = 0;
+#define INCREMENT_SIZE(type, size, name, camel_name)   \
+    string_number += info[type].number();              \
+    string_bytes += info[type].bytes();
+  STRING_TYPE_LIST(INCREMENT_SIZE)
+#undef INCREMENT_SIZE
+  if (string_bytes > 0) {
+    LOG(HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes));
+  }
+
+  for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) {
+    if (info[i].bytes() > 0) {
+      LOG(HeapSampleItemEvent(info[i].name(), info[i].number(),
+                              info[i].bytes()));
+    }
+  }
+
+  js_cons_profile.PrintStats();
+  js_retainer_profile.PrintStats();
+
+  LOG(HeapSampleEndEvent("Heap", "allocated"));
+}
+
+
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+
+} }  // namespace v8::internal