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

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index b911ad1ee68006ba6358f33c4f4c50996f4b094b..00b3d1aa4f5f5324858b565a562e374bb8224bb7 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -54,6 +54,14 @@
 namespace v8 {
 namespace internal {
 
+namespace {
+const char* kNewSpaceName = "new_space";
+const char* kOldSpaceName = "old_space";
+const char* kCodeSpaceName = "code_space";
+const char* kMapSpaceName = "map_space";
+const char* kLoSpaceName = "large_object_space";
+}  // namespace
+
 
 Heap::Heap()
     : amount_of_external_allocated_memory_(0),
@@ -451,6 +459,23 @@ intptr_t Heap::SizeOfObjects() {
 }
 
 
+const char* Heap::GetSpaceName(int idx) {
+  switch (idx) {
+    case NEW_SPACE:
+      return kNewSpaceName;
+    case OLD_SPACE:
+      return kOldSpaceName;
+    case MAP_SPACE:
+      return kMapSpaceName;
+    case CODE_SPACE:
+      return kCodeSpaceName;
+    case LO_SPACE:
+      return kLoSpaceName;

[rmcilroy, 2015/04/15 10:21:42]

add 'default' case with UNREACHABLE(); to ensure we always hit a valid index
(and remove the default nullptr return below) 

[ssid, 2015/04/15 10:43:58]

Added UNREACHABLE and keeping return null since compiler gives error if i dont
return at the end.

+  }
+  return nullptr;
+}
+
+
 void Heap::ClearAllICsByKind(Code::Kind kind) {
   HeapObjectIterator it(code_space());