Adding V8 api to get memory statistics of spaces in V8::Heap.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 28c84106df4c260cfbd2e96972a12efcd1f10964..89e3b3714bef60c836b1d160eeda194332e95f0b 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -30,6 +30,7 @@
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/global-handles.h"
+#include "src/heap/spaces.h"
 #include "src/heap-profiler.h"
 #include "src/heap-snapshot-generator-inl.h"
 #include "src/icu_util.h"
@@ -6957,15 +6958,55 @@ Isolate::SuppressMicrotaskExecutionScope::~SuppressMicrotaskExecutionScope() {
 }
 
 
+class HeapStatisticsHelper {

[rmcilroy, 2015/04/13 12:48:23]

I don't think we should have a seperate class just for this, and in any case it
probably shouldn't be in api.cc. Could you move the filling-in of these stats to
heap.cc (I'm not sure about how the public / internal dependencies would look
though)?

+ public:
+  static void ExtractHeapStatistics(HeapStatistics* heap_statistics,
+                                    i::Heap* heap) {
+    heap_statistics->total_heap_size_ = heap->CommittedMemory();
+    heap_statistics->total_heap_size_executable_ =
+        heap->CommittedMemoryExecutable();
+    heap_statistics->total_physical_size_ = heap->CommittedPhysicalMemory();
+    heap_statistics->used_heap_size_ = heap->SizeOfObjects();
+    heap_statistics->heap_size_limit_ = heap->MaxReserved();
+
+    heap_statistics->new_space_statistics()->size_of_objects_ =
+        heap->new_space()->Size();
+    heap_statistics->new_space_statistics()->available_memory_ =
+        heap->new_space()->Available();
+    heap_statistics->new_space_statistics()->committed_memory_ =
+        heap->new_space()->CommittedMemory();
+
+    heap_statistics->lo_space_statistics()->size_of_objects_ =
+        heap->lo_space()->SizeOfObjects();
+    heap_statistics->lo_space_statistics()->available_memory_ =
+        heap->lo_space()->Available();
+    heap_statistics->lo_space_statistics()->committed_memory_ =
+        heap->lo_space()->CommittedMemory();
+
+    ExtractSpaceStatisticsFromPagedSpace(
+        heap->old_space(), heap_statistics->old_space_statistics());
+    ExtractSpaceStatisticsFromPagedSpace(
+        heap->code_space(), heap_statistics->code_space_statistics());
+    ExtractSpaceStatisticsFromPagedSpace(
+        heap->map_space(), heap_statistics->map_space_statistics());
+    ExtractSpaceStatisticsFromPagedSpace(
+        heap->cell_space(), heap_statistics->cell_space_statistics());
+  }
+
+  static void ExtractSpaceStatisticsFromPagedSpace(
+      i::PagedSpace* paged_space,
+      HeapStatistics::SpaceStatistics* space_stats) {
+    space_stats->size_of_objects_ = paged_space->SizeOfObjects();
+    space_stats->committed_memory_ = paged_space->CommittedMemory();
+    space_stats->available_memory_ = paged_space->Available();
+  }
+};
+
+
 void Isolate::GetHeapStatistics(HeapStatistics* heap_statistics) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   i::Heap* heap = isolate->heap();
-  heap_statistics->total_heap_size_ = heap->CommittedMemory();
-  heap_statistics->total_heap_size_executable_ =
-      heap->CommittedMemoryExecutable();
-  heap_statistics->total_physical_size_ = heap->CommittedPhysicalMemory();
-  heap_statistics->used_heap_size_ = heap->SizeOfObjects();
-  heap_statistics->heap_size_limit_ = heap->MaxReserved();
+  HeapStatisticsHelper::ExtractHeapStatistics(heap_statistics, heap);
 }