Added zone tracing

Added PrintF output whenever a zone is created or destroyed. Also
enables setting of a name for each zone, which can then be shown
in the v8-heap-stats tool: https://github.com/mlippautz/v8-heap-stats/pull/2

BUG=v8:5489

Review-Url: https://codereview.chromium.org/2397573007
Cr-Commit-Position: refs/heads/master@{#40168}

src/isolate.cc

@@ -1936,6 +1936,7 @@ class VerboseAccountingAllocator : public AccountingAllocator {
       : heap_(heap),
         last_memory_usage_(0),
         last_pool_size_(0),
+        nesting_deepth_(0),
         allocation_sample_bytes_(allocation_sample_bytes),
         pool_sample_bytes_(pool_sample_bytes) {}
 
@@ -1948,7 +1949,7 @@ class VerboseAccountingAllocator : public AccountingAllocator {
       if (last_memory_usage_.Value() + allocation_sample_bytes_ <
               malloced_current ||
           last_pool_size_.Value() + pool_sample_bytes_ < pooled_current) {
-        PrintJSON(malloced_current, pooled_current);
+        PrintMemoryJSON(malloced_current, pooled_current);
         last_memory_usage_.SetValue(malloced_current);
         last_pool_size_.SetValue(pooled_current);
       }
@@ -1964,14 +1965,49 @@ class VerboseAccountingAllocator : public AccountingAllocator {
     if (malloced_current + allocation_sample_bytes_ <
             last_memory_usage_.Value() ||
         pooled_current + pool_sample_bytes_ < last_pool_size_.Value()) {
-      PrintJSON(malloced_current, pooled_current);
+      PrintMemoryJSON(malloced_current, pooled_current);
       last_memory_usage_.SetValue(malloced_current);
       last_pool_size_.SetValue(pooled_current);
     }
   }
 
+  void ZoneCreation(const Zone* zone) override {
+    double time = heap_->isolate()->time_millis_since_init();
+    PrintF(
+        "{"
+        "\"type\": \"zonecreation\", "
+        "\"isolate\": \"%p\", "
+        "\"time\": %f, "
+        "\"ptr\": \"%p\", "
+        "\"name\": \"%s\","
+        "\"nesting\": %zu"
+        "}\n",
+        reinterpret_cast<void*>(heap_->isolate()), time,
+        reinterpret_cast<const void*>(zone), zone->name(),
+        nesting_deepth_.Value());
+    nesting_deepth_.Increment(1);
+  }
+
+  void ZoneDestruction(const Zone* zone) override {
+    nesting_deepth_.Decrement(1);
+    double time = heap_->isolate()->time_millis_since_init();
+    PrintF(
+        "{"
+        "\"type\": \"zonedestruction\", "
+        "\"isolate\": \"%p\", "
+        "\"time\": %f, "
+        "\"ptr\": \"%p\", "
+        "\"name\": \"%s\", "
+        "\"size\": %zu,"
+        "\"nesting\": %zu"
+        "}\n",
+        reinterpret_cast<void*>(heap_->isolate()), time,
+        reinterpret_cast<const void*>(zone), zone->name(),
+        zone->allocation_size(), nesting_deepth_.Value());
+  }
+
  private:
-  void PrintJSON(size_t malloced, size_t pooled) {
+  void PrintMemoryJSON(size_t malloced, size_t pooled) {
     // Note: Neither isolate, nor heap is locked, so be careful with accesses
     // as the allocator is potentially used on a concurrent thread.
     double time = heap_->isolate()->time_millis_since_init();
@@ -1989,6 +2025,7 @@ class VerboseAccountingAllocator : public AccountingAllocator {
   Heap* heap_;
   base::AtomicNumber<size_t> last_memory_usage_;
   base::AtomicNumber<size_t> last_pool_size_;
+  base::AtomicNumber<size_t> nesting_deepth_;
   size_t allocation_sample_bytes_, pool_sample_bytes_;
 };
 

src/zone/accounting-allocator.h

@@ -35,6 +35,9 @@ class V8_EXPORT_PRIVATE AccountingAllocator {
 
   void MemoryPressureNotification(MemoryPressureLevel level);
 
+  virtual void ZoneCreation(const Zone* zone) {}
+  virtual void ZoneDestruction(const Zone* zone) {}
+
  private:
   static const uint8_t kMinSegmentSizePower = 13;
   static const uint8_t kMaxSegmentSizePower = 18;

src/zone/zone.cc

@@ -41,15 +41,20 @@ const size_t kASanRedzoneBytes = 0;
 
 }  // namespace
 
-Zone::Zone(AccountingAllocator* allocator)
+Zone::Zone(AccountingAllocator* allocator, const char* name)
     : allocation_size_(0),
       segment_bytes_allocated_(0),
       position_(0),
       limit_(0),
       allocator_(allocator),
-      segment_head_(nullptr) {}
+      segment_head_(nullptr),
+      name_(name) {
+  allocator_->ZoneCreation(this);
+}
 
 Zone::~Zone() {
+  allocator_->ZoneDestruction(this);
+
   DeleteAll();
 
   DCHECK(segment_bytes_allocated_ == 0);

src/zone/zone.h

@@ -31,7 +31,7 @@ namespace internal {
 // from multi-threaded code.
 class V8_EXPORT_PRIVATE Zone final {
  public:
-  explicit Zone(AccountingAllocator* allocator);
+  explicit Zone(AccountingAllocator* allocator, const char* name = "unnamed");
   ~Zone();
 
   // Allocate 'size' bytes of memory in the Zone; expands the Zone by
@@ -50,6 +50,8 @@ class V8_EXPORT_PRIVATE Zone final {
     return segment_bytes_allocated_ > kExcessLimit;
   }
 
+  const char* name() const { return name_; }
+
   size_t allocation_size() const { return allocation_size_; }
 
   AccountingAllocator* allocator() const { return allocator_; }
@@ -105,6 +107,7 @@ class V8_EXPORT_PRIVATE Zone final {
   AccountingAllocator* allocator_;
 
   Segment* segment_head_;
+  const char* name_;
 };
 
 // ZoneObject is an abstraction that helps define classes of objects