[tracing] Adding class-wise memory statistics to blink gc memory dumps

Source/platform/heap/ThreadState.cpp

Index: Source/platform/heap/ThreadState.cpp
diff --git a/Source/platform/heap/ThreadState.cpp b/Source/platform/heap/ThreadState.cpp
index 8c04580dfc449885f57d413eae4add969da34d43..6b28a80f937b90cbc314b7988a4d26ae870501a1 100644
--- a/Source/platform/heap/ThreadState.cpp
+++ b/Source/platform/heap/ThreadState.cpp
@@ -33,12 +33,14 @@
 
 #include "platform/ScriptForbiddenScope.h"
 #include "platform/TraceEvent.h"
+#include "platform/heap/BlinkGCMemoryDumpProvider.h"
 #include "platform/heap/CallbackStack.h"
 #include "platform/heap/Handle.h"
 #include "platform/heap/Heap.h"
 #include "platform/heap/MarkingVisitor.h"
 #include "platform/heap/SafePoint.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebMemoryAllocatorDump.h"
 #include "public/platform/WebScheduler.h"
 #include "public/platform/WebThread.h"
 #include "public/platform/WebTraceLocation.h"
@@ -380,6 +382,18 @@ void ThreadState::visitPersistents(Visitor* visitor)
     }
 }
 
+size_t ThreadState::GCSnapshotInfo::getClassTag(const GCInfo* gcInfo)
+{
+    ClassTagMap::AddResult result = classTags.add(gcInfo, classTags.size());
+    if (result.isNewEntry) {
+        liveCount.append(0);
+        deadCount.append(0);
+        liveSize.append(0);
+        deadSize.append(0);
+    }
+    return result.storedValue->value;
+}
+
 #if ENABLE(GC_PROFILING)
 const GCInfo* ThreadState::findGCInfo(Address address)
 {
@@ -1376,6 +1390,7 @@ void ThreadState::promptlyFreed(size_t gcInfoIndex)
 
 void ThreadState::takeSnapshot()
 {
+    GCSnapshotInfo info;
     ASSERT(isInGC());
 
     int numberOfHeapsReported = 0;
@@ -1384,7 +1399,8 @@ void ThreadState::takeSnapshot()
         numberOfHeapsReported++;                                                                               \
         String allocatorBaseName;                                                                              \
         allocatorBaseName = String::format("blink_gc/thread_%lu/heaps/" #HeapType, (unsigned long)(m_thread)); \
-        m_heaps[HeapType##HeapIndex]->takeSnapshot(allocatorBaseName);                                         \
+        m_heaps[HeapType##HeapIndex]->takeSnapshot(allocatorBaseName, info);                                         \
+        m_heaps[HeapType##HeapIndex]->takeFreelistSnapshot(allocatorBaseName);                                 \
     }
 
     SNAPSHOT_HEAP(NormalPage1);
@@ -1404,6 +1420,20 @@ void ThreadState::takeSnapshot()
     ASSERT(numberOfHeapsReported == NumberOfHeaps);
 
 #undef SNAPSHOT_HEAP
+
+    Vector<String> classNameVector(info.classTags.size());
+    for (GCSnapshotInfo::ClassTagMap::iterator it = info.classTags.begin(); it != info.classTags.end(); ++it)
+        classNameVector[it->value] = it->key->m_className;
+  
+    for (size_t i = 0; i < classNameVector.size(); ++i) {
+        String classDumpName = classNameVector[i].isolatedCopy();
+        classDumpName.insert(String("blink_gc/classes/"), 0);
+        WebMemoryAllocatorDump* classDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(classDumpName);
+        classDump->AddScalar("live_count", "objects", info.liveCount[i]);
+        classDump->AddScalar("dead_count", "objects", info.deadCount[i]);
+        classDump->AddScalar("live_size", "bytes", info.liveSize[i]);
+        classDump->AddScalar("dead_size", "bytes", info.deadSize[i]);
+    }
 }
 
 #if ENABLE(GC_PROFILING)