Sampling heap profiler data structure changes

src/profiler/sampling-heap-profiler.h

 // Copyright 2015 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.
 
 #ifndef V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 #define V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 51 matching lines @@
     int get_script_id() const { return script_id_; }
     int get_start_position() const { return start_position_; }
 
    private:
     const char* const name_;
     const char* script_name_;
     int script_id_;
     const int start_position_;
   };
 
-  class SampledAllocation {
+  class AllocationNode;
+
+  struct Sample {
+    size_t size;
+    AllocationNode* owner;
+    Global<Value>* global;

[ofrobots, 2016/02/14 23:57:42]

It is more idiomatic to keep Globals (and Locals and Persistents) by value
rather than pointer. I suspect the reason you are keeping a pointer is to get
around issues of Global (and hence Sample) not being copy-able. That limitation
is by design. Instead add a constructor so that you can initialize Global (as
value) in place. It would also be good to explicitly mark Sample as not copyable
(by using DISALLOW_COPY_AND_ASSIGN).

[mattloring, 2016/02/16 05:28:40]

Globals are held by value now. How does DISALLOW_COPY_AND_ASSIGN work with
structs? Where should the call be?

+  };
+
+  class AllocationNode {
    public:
-    SampledAllocation(SamplingHeapProfiler* sampling_heap_profiler,
-                      Isolate* isolate, Local<Value> local, size_t size,
-                      int max_frames);
-    ~SampledAllocation() {
-      for (auto info : stack_) {
-        delete info;
+    explicit AllocationNode(FunctionInfo* info)
+        : script_id_(info->get_script_id()),
+          script_position_(info->get_start_position()),
+          name_(info->get_name()) {}
+    ~AllocationNode() {
+      for (auto child : children_) {
+        delete child;
       }
-      global_.Reset();  // drop the reference.
     }
-    size_t get_size() const { return size_; }
-    const std::vector<FunctionInfo*>& get_stack() const { return stack_; }
 
    private:
-    static void OnWeakCallback(const WeakCallbackInfo<SampledAllocation>& data);
+    std::map<size_t, unsigned int> allocations_;
+    std::vector<AllocationNode*> children_;
+    int script_id_;
+    int script_position_;
+    const char* name_;
 
-    SamplingHeapProfiler* const sampling_heap_profiler_;
-    Global<Value> global_;
-    std::vector<FunctionInfo*> stack_;
-    const size_t size_;
+    friend class SamplingHeapProfiler;
 
-    DISALLOW_COPY_AND_ASSIGN(SampledAllocation);
+    DISALLOW_COPY_AND_ASSIGN(AllocationNode);
   };
 
  private:
   Heap* heap() const { return heap_; }
 
   void SampleObject(Address soon_object, size_t size);
 
+  static void OnWeakCallback(const WeakCallbackInfo<Sample>& data);
+
   // Methods that construct v8::AllocationProfile.
-  v8::AllocationProfile::Node* AddStack(
-      AllocationProfile* profile, const std::map<int, Script*>& scripts,
-      const std::vector<FunctionInfo*>& stack);
-  v8::AllocationProfile::Node* FindOrAddChildNode(
-      AllocationProfile* profile, const std::map<int, Script*>& scripts,
-      v8::AllocationProfile::Node* parent, FunctionInfo* function_info);
-  v8::AllocationProfile::Node* AllocateNode(
-      AllocationProfile* profile, const std::map<int, Script*>& scripts,
-      FunctionInfo* function_info);
+  v8::AllocationProfile::Node* GenerateProfile(
+      AllocationProfile* profile, SamplingHeapProfiler::AllocationNode* node,
+      const std::map<int, Script*>& scripts);
+  AllocationNode* AddStack(const std::vector<FunctionInfo*>& stack);
+  std::vector<FunctionInfo*> CollectStack(int max_frames);
+  AllocationNode* FindOrAddChildNode(AllocationNode* parent,
+                                     FunctionInfo* function_info);
 
   Isolate* const isolate_;
   Heap* const heap_;
   base::SmartPointer<SamplingAllocationObserver> new_space_observer_;
   base::SmartPointer<SamplingAllocationObserver> other_spaces_observer_;
   StringsStorage* const names_;
-  std::set<SampledAllocation*> samples_;
+  AllocationNode* profile_root_;
   const int stack_depth_;
 
   friend class SamplingAllocationObserver;
 };
 
 class SamplingAllocationObserver : public AllocationObserver {
  public:
   SamplingAllocationObserver(Heap* heap, intptr_t step_size, uint64_t rate,
                              SamplingHeapProfiler* profiler,
                              base::RandomNumberGenerator* random)
@@ skipping 19 matching lines @@
   SamplingHeapProfiler* const profiler_;
   Heap* const heap_;
   base::RandomNumberGenerator* const random_;
   uint64_t const rate_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PROFILER_SAMPLING_HEAP_PROFILER_H_