Separating transitions from descriptors.

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index 2e58c0949e5020c85008cc9621f4a071a3b2f82e..679e9dc90c3dde50dddbf23d3453b2dcdaa13058 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -273,15 +273,11 @@ void JSObject::PrintProperties(FILE* out) {
           descs->GetCallbacksObject(i)->ShortPrint(out);
           PrintF(out, " (callback)\n");
           break;
-        case MAP_TRANSITION:
-          PrintF(out, "(map transition)\n");
-          break;
-        case CONSTANT_TRANSITION:
-          PrintF(out, "(constant transition)\n");
-          break;
         case NORMAL:  // only in slow mode
         case HANDLER:  // only in lookup results, not in descriptors
         case INTERCEPTOR:  // only in lookup results, not in descriptors
+        // There are no transitions in the descriptor array.
+        case TRANSITION:
         case NONEXISTENT:
           UNREACHABLE();
           break;
@@ -408,6 +404,37 @@ void JSObject::PrintElements(FILE* out) {
 }
 
 
+void JSObject::PrintTransitions(FILE* out) {
+  if (!map()->HasTransitionArray()) return;
+  TransitionArray* transitions = map()->transitions();
+  for (int i = 0; i < transitions->number_of_transitions(); i++) {
+    PrintF(out, "   ");
+    transitions->GetKey(i)->StringPrint(out);
+    PrintF(out, ": ");
+    switch (transitions->GetTargetDetails(i).type()) {
+      case FIELD: {
+        PrintF(out, " (transition to field)\n");
+        break;
+      }
+      case CONSTANT_FUNCTION:
+        PrintF(out, " (transition to constant function)\n");
+        break;
+      case CALLBACKS:
+        PrintF(out, " (transition to callback)\n");
+        break;
+      // Values below are never in the target descriptor array.
+      case NORMAL:
+      case HANDLER:
+      case INTERCEPTOR:
+      case TRANSITION:
+      case NONEXISTENT:
+        UNREACHABLE();
+        break;
+    }
+  }
+}
+
+
 void JSObject::JSObjectPrint(FILE* out) {
   PrintF(out, "%p: [JSObject]\n", reinterpret_cast<void*>(this));
   PrintF(out, " - map = %p [", reinterpret_cast<void*>(map()));
@@ -417,11 +444,9 @@ void JSObject::JSObjectPrint(FILE* out) {
   PrintF(out,
          "]\n - prototype = %p\n",
          reinterpret_cast<void*>(GetPrototype()));
-  PrintF(out,
-         " - elements transition to = %p\n",
-         reinterpret_cast<void*>(map()->elements_transition_map()));
   PrintF(out, " {\n");
   PrintProperties(out);
+  PrintTransitions(out);
   PrintElements(out);
   PrintF(out, " }\n");
 }
@@ -537,6 +562,10 @@ void Map::MapPrint(FILE* out) {
   }
   PrintF(out, " - instance descriptors: ");
   instance_descriptors()->ShortPrint(out);
+  if (HasTransitionArray()) {
+    PrintF(out, "\n - transitions: ");
+    transitions()->ShortPrint(out);
+  }
   PrintF(out, "\n - prototype: ");
   prototype()->ShortPrint(out);
   PrintF(out, "\n - constructor: ");
@@ -1024,6 +1053,37 @@ void DescriptorArray::PrintDescriptors(FILE* out) {
 }
 
 
+void TransitionArray::PrintTransitions(FILE* out) {
+  PrintF(out, "Transition array  %d\n", number_of_transitions());
+  for (int i = 0; i < number_of_transitions(); i++) {
+    PrintF(out, " %d: ", i);
+    GetKey(i)->StringPrint(out);
+    PrintF(out, ": ");
+    switch (GetTargetDetails(i).type()) {
+      case FIELD: {
+        PrintF(out, " (transition to field)\n");
+        break;
+      }
+      case CONSTANT_FUNCTION:
+        PrintF(out, " (transition to constant function)\n");
+        break;
+      case CALLBACKS:
+        PrintF(out, " (transition to callback)\n");
+        break;
+      // Values below are never in the target descriptor array.
+      case NORMAL:
+      case HANDLER:
+      case INTERCEPTOR:
+      case TRANSITION:
+      case NONEXISTENT:
+        UNREACHABLE();
+        break;
+    }
+  }
+  PrintF(out, "\n");
+}
+
+
 #endif  // OBJECT_PRINT