Track JS allocations as they arrive with no affection on performance when tracking is switched off

src/heap.cc

 // Copyright 2012 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
@@ skipping 2082 matching lines @@
                                    int size)) {
     // Copy the content of source to target.
     heap->CopyBlock(target->address(), source->address(), size);
 
     // Set the forwarding address.
     source->set_map_word(MapWord::FromForwardingAddress(target));
 
     if (logging_and_profiling_mode == LOGGING_AND_PROFILING_ENABLED) {
       // Update NewSpace stats if necessary.
       RecordCopiedObject(heap, target);
-      HEAP_PROFILE(heap, ObjectMoveEvent(source->address(), target->address()));
+      HEAP_PROFILE(heap,
+                   ObjectMoveEvent(source->address(), target->address(), size));
       Isolate* isolate = heap->isolate();
       if (isolate->logger()->is_logging_code_events() ||
           isolate->cpu_profiler()->is_profiling()) {
         if (target->IsSharedFunctionInfo()) {
           PROFILE(isolate, SharedFunctionInfoMoveEvent(
               source->address(), target->address()));
         }
       }
     }
 
@@ skipping 2953 matching lines @@
               source->address(),
               object_size);
   }
 
   if (adjusted_object_size > object_size) {
     AllocationMemento* alloc_memento = reinterpret_cast<AllocationMemento*>(
         reinterpret_cast<Address>(clone) + object_size);
     alloc_memento->set_map_no_write_barrier(allocation_memento_map());
     ASSERT(site->map() == allocation_site_map());
     alloc_memento->set_allocation_site(site, SKIP_WRITE_BARRIER);
+
+    HeapProfiler* profiler = isolate()->heap_profiler();
+    if (profiler->is_tracking_allocations()) {
+      profiler->UpdateObjectSizeEvent(HeapObject::cast(clone)->address(),
+                               object_size);
+      profiler->NewObjectEvent(alloc_memento->address(),
+                               adjusted_object_size - object_size);
+    }
   }
 
   SLOW_ASSERT(
       JSObject::cast(clone)->GetElementsKind() == source->GetElementsKind());
   FixedArrayBase* elements = FixedArrayBase::cast(source->elements());
   FixedArray* properties = FixedArray::cast(source->properties());
   // Update elements if necessary.
   if (elements->length() > 0) {
     Object* elem;
     { MaybeObject* maybe_elem;
@@ skipping 2998 matching lines @@
   if (FLAG_concurrent_recompilation) {
     heap_->relocation_mutex_->Lock();
 #ifdef DEBUG
     heap_->relocation_mutex_locked_by_optimizer_thread_ =
         heap_->isolate()->optimizing_compiler_thread()->IsOptimizerThread();
 #endif  // DEBUG
   }
 }
 
 } }  // namespace v8::internal