Reland "Record allocation stack traces"

src/heap-snapshot-generator.cc

Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index b3d905a75ee3d156f7f3c955ca8034e47700d766..b7b7f2215b749f3830d555e3a0f43a20f8a30f20 100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -29,6 +29,7 @@
 
 #include "heap-snapshot-generator-inl.h"
 
+#include "allocation-tracker.h"
 #include "code-stubs.h"
 #include "heap-profiler.h"
 #include "debug.h"
@@ -748,7 +749,8 @@ size_t HeapObjectsMap::GetUsedMemorySize() const {
 HeapSnapshotsCollection::HeapSnapshotsCollection(Heap* heap)
     : is_tracking_objects_(false),
       names_(heap),
-      ids_(heap) {
+      ids_(heap),
+      allocation_tracker_(NULL) {
 }
 
 
@@ -758,10 +760,29 @@ static void DeleteHeapSnapshot(HeapSnapshot** snapshot_ptr) {
 
 
 HeapSnapshotsCollection::~HeapSnapshotsCollection() {
+  delete allocation_tracker_;
   snapshots_.Iterate(DeleteHeapSnapshot);
 }
 
 
+void HeapSnapshotsCollection::StartHeapObjectsTracking() {
+  ids_.UpdateHeapObjectsMap();
+  if (allocation_tracker_ == NULL) {
+    allocation_tracker_ = new AllocationTracker(&ids_, names());
+  }
+  is_tracking_objects_ = true;
+}
+
+
+void HeapSnapshotsCollection::StopHeapObjectsTracking() {
+  ids_.StopHeapObjectsTracking();
+  if (allocation_tracker_ != NULL) {
+    delete allocation_tracker_;
+    allocation_tracker_ = NULL;
+  }
+}
+
+
 HeapSnapshot* HeapSnapshotsCollection::NewSnapshot(const char* name,
                                                    unsigned uid) {
   is_tracking_objects_ = true;  // Start watching for heap objects moves.
@@ -805,6 +826,15 @@ Handle<HeapObject> HeapSnapshotsCollection::FindHeapObjectById(
 }
 
 
+void HeapSnapshotsCollection::NewObjectEvent(Address addr, int size) {
+  DisallowHeapAllocation no_allocation;
+  ids_.NewObject(addr, size);
+  if (allocation_tracker_ != NULL) {
+    allocation_tracker_->NewObjectEvent(addr, size);
+  }
+}
+
+
 size_t HeapSnapshotsCollection::GetUsedMemorySize() const {
   size_t size = sizeof(*this);
   size += names_.GetUsedMemorySize();
@@ -2645,6 +2675,10 @@ const int HeapSnapshotJSONSerializer::kEdgeFieldsCount = 3;
 const int HeapSnapshotJSONSerializer::kNodeFieldsCount = 5;
 
 void HeapSnapshotJSONSerializer::Serialize(v8::OutputStream* stream) {
+  if (AllocationTracker* allocation_tracker =
+      snapshot_->collection()->allocation_tracker()) {
+    allocation_tracker->PrepareForSerialization();
+  }
   ASSERT(writer_ == NULL);
   writer_ = new OutputStreamWriter(stream);
   SerializeImpl();
@@ -2668,6 +2702,16 @@ void HeapSnapshotJSONSerializer::SerializeImpl() {
   SerializeEdges();
   if (writer_->aborted()) return;
   writer_->AddString("],\n");
+
+  writer_->AddString("\"trace_function_infos\":[");
+  SerializeTraceNodeInfos();
+  if (writer_->aborted()) return;
+  writer_->AddString("],\n");
+  writer_->AddString("\"trace_tree\":[");
+  SerializeTraceTree();
+  if (writer_->aborted()) return;
+  writer_->AddString("],\n");
+
   writer_->AddString("\"strings\":[");
   SerializeStrings();
   if (writer_->aborted()) return;
@@ -2828,7 +2872,20 @@ void HeapSnapshotJSONSerializer::SerializeSnapshot() {
             JSON_S("shortcut") ","
             JSON_S("weak")) ","
         JSON_S("string_or_number") ","
-        JSON_S("node"))));
+        JSON_S("node")) ","
+    JSON_S("trace_function_info_fields") ":" JSON_A(
+        JSON_S("function_id") ","
+        JSON_S("name") ","
+        JSON_S("script_name") ","
+        JSON_S("script_id") ","
+        JSON_S("line") ","
+        JSON_S("column")) ","
+    JSON_S("trace_node_fields") ":" JSON_A(
+        JSON_S("id") ","
+        JSON_S("function_id") ","
+        JSON_S("count") ","
+        JSON_S("size") ","
+        JSON_S("children"))));
 #undef JSON_S
 #undef JSON_O
 #undef JSON_A
@@ -2836,6 +2893,13 @@ void HeapSnapshotJSONSerializer::SerializeSnapshot() {
   writer_->AddNumber(snapshot_->entries().length());
   writer_->AddString(",\"edge_count\":");
   writer_->AddNumber(snapshot_->edges().length());
+  writer_->AddString(",\"trace_function_count\":");
+  uint32_t count = 0;
+  AllocationTracker* tracker = snapshot_->collection()->allocation_tracker();
+  if (tracker) {
+    count = tracker->id_to_function_info()->occupancy();
+  }
+  writer_->AddNumber(count);
 }
 
 
@@ -2849,6 +2913,100 @@ static void WriteUChar(OutputStreamWriter* w, unibrow::uchar u) {
 }
 
 
+void HeapSnapshotJSONSerializer::SerializeTraceTree() {
+  AllocationTracker* tracker = snapshot_->collection()->allocation_tracker();
+  if (!tracker) return;
+  AllocationTraceTree* traces = tracker->trace_tree();
+  SerializeTraceNode(traces->root());
+}
+
+
+void HeapSnapshotJSONSerializer::SerializeTraceNode(AllocationTraceNode* node) {
+  // The buffer needs space for 4 unsigned ints, 4 commas, [ and \0
+  const int kBufferSize =
+      4 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned  // NOLINT
+      + 4 + 1 + 1;
+  EmbeddedVector<char, kBufferSize> buffer;
+  int buffer_pos = 0;
+  buffer_pos = utoa(node->id(), buffer, buffer_pos);
+  buffer[buffer_pos++] = ',';
+  buffer_pos = utoa(node->function_id(), buffer, buffer_pos);
+  buffer[buffer_pos++] = ',';
+  buffer_pos = utoa(node->allocation_count(), buffer, buffer_pos);
+  buffer[buffer_pos++] = ',';
+  buffer_pos = utoa(node->allocation_size(), buffer, buffer_pos);
+  buffer[buffer_pos++] = ',';
+  buffer[buffer_pos++] = '[';
+  buffer[buffer_pos++] = '\0';
+  writer_->AddString(buffer.start());
+
+  Vector<AllocationTraceNode*> children = node->children();
+  for (int i = 0; i < children.length(); i++) {
+    if (i > 0) {
+      writer_->AddCharacter(',');
+    }
+    SerializeTraceNode(children[i]);
+  }
+  writer_->AddCharacter(']');
+}
+
+
+// 0-based position is converted to 1-based during the serialization.
+static int SerializePosition(int position, const Vector<char>& buffer,
+                             int buffer_pos) {
+  if (position == -1) {
+    buffer[buffer_pos++] = '0';
+  } else {
+    ASSERT(position >= 0);
+    buffer_pos = utoa(static_cast<unsigned>(position + 1), buffer, buffer_pos);
+  }
+  return buffer_pos;
+}
+
+
+void HeapSnapshotJSONSerializer::SerializeTraceNodeInfos() {
+  AllocationTracker* tracker = snapshot_->collection()->allocation_tracker();
+  if (!tracker) return;
+  // The buffer needs space for 6 unsigned ints, 6 commas, \n and \0
+  const int kBufferSize =
+      6 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned  // NOLINT
+      + 6 + 1 + 1;
+  EmbeddedVector<char, kBufferSize> buffer;
+  HashMap* id_to_function_info = tracker->id_to_function_info();
+  bool first_entry = true;
+  for (HashMap::Entry* p = id_to_function_info->Start();
+       p != NULL;
+       p = id_to_function_info->Next(p)) {
+    SnapshotObjectId id =
+        static_cast<SnapshotObjectId>(reinterpret_cast<intptr_t>(p->key));
+    AllocationTracker::FunctionInfo* info =
+        reinterpret_cast<AllocationTracker::FunctionInfo* >(p->value);
+    int buffer_pos = 0;
+    if (first_entry) {
+      first_entry = false;
+    } else {
+      buffer[buffer_pos++] = ',';
+    }
+    buffer_pos = utoa(id, buffer, buffer_pos);
+    buffer[buffer_pos++] = ',';
+    buffer_pos = utoa(GetStringId(info->name), buffer, buffer_pos);
+    buffer[buffer_pos++] = ',';
+    buffer_pos = utoa(GetStringId(info->script_name), buffer, buffer_pos);
+    buffer[buffer_pos++] = ',';
+    // The cast is safe because script id is a non-negative Smi.
+    buffer_pos = utoa(static_cast<unsigned>(info->script_id), buffer,
+        buffer_pos);
+    buffer[buffer_pos++] = ',';
+    buffer_pos = SerializePosition(info->line, buffer, buffer_pos);
+    buffer[buffer_pos++] = ',';
+    buffer_pos = SerializePosition(info->column, buffer, buffer_pos);
+    buffer[buffer_pos++] = '\n';
+    buffer[buffer_pos++] = '\0';
+    writer_->AddString(buffer.start());
+  }
+}
+
+
 void HeapSnapshotJSONSerializer::SerializeString(const unsigned char* s) {
   writer_->AddCharacter('\n');
   writer_->AddCharacter('\"');