In-place shrinking of descriptor arrays with non-live transitions.

src/ic.cc

Index: src/ic.cc
diff --git a/src/ic.cc b/src/ic.cc
index 47a72b495636465761ce27fe4a0d97a107430f78..10c737b68313ad3b35570560a302d8facede1baf 100644
--- a/src/ic.cc
+++ b/src/ic.cc
@@ -1301,7 +1301,7 @@ void KeyedLoadIC::UpdateCaches(LookupResult* lookup,
 
 static bool StoreICableLookup(LookupResult* lookup) {
   // Bail out if we didn't find a result.
-  if (!lookup->IsFound() || lookup->type() == NULL_DESCRIPTOR) return false;
+  if (!lookup->IsFound()) return false;
 
   // Bail out if inline caching is not allowed.
   if (!lookup->IsCacheable()) return false;
@@ -1439,8 +1439,6 @@ void StoreIC::UpdateCaches(LookupResult* lookup,
   ASSERT(StoreICableLookup(lookup));
   // These are not cacheable, so we never see such LookupResults here.
   ASSERT(lookup->type() != HANDLER);
-  // We get only called for properties or transitions, see StoreICableLookup.
-  ASSERT(lookup->type() != NULL_DESCRIPTOR);

[Michael Starzinger, 2012/06/25 11:21:57]

We should actually keep this and assert against NONEXISTENT now.

[Toon Verwaest, 2012/06/25 12:20:48]

As discussed offline, replaced with IsFound().

On 2012/06/25 11:21:57, Michael Starzinger wrote:

 
   // If the property has a non-field type allowing map transitions
   // where there is extra room in the object, we leave the IC in its
@@ -1512,8 +1510,8 @@ void StoreIC::UpdateCaches(LookupResult* lookup,
     case CONSTANT_FUNCTION:
     case CONSTANT_TRANSITION:
       return;
+    case NONEXISTENT:
     case HANDLER:
-    case NULL_DESCRIPTOR:
       UNREACHABLE();
       return;
   }
@@ -1941,8 +1939,6 @@ void KeyedStoreIC::UpdateCaches(LookupResult* lookup,
   ASSERT(StoreICableLookup(lookup));
   // These are not cacheable, so we never see such LookupResults here.
   ASSERT(lookup->type() != HANDLER);
-  // We get only called for properties or transitions, see StoreICableLookup.
-  ASSERT(lookup->type() != NULL_DESCRIPTOR);

[Michael Starzinger, 2012/06/25 11:21:57]

Likewise.

[Toon Verwaest, 2012/06/25 12:20:48]

Done.

 
   // If the property has a non-field type allowing map transitions
   // where there is extra room in the object, we leave the IC in its
@@ -1981,7 +1977,7 @@ void KeyedStoreIC::UpdateCaches(LookupResult* lookup,
           : generic_stub();
       break;
     case HANDLER:
-    case NULL_DESCRIPTOR:
+    case NONEXISTENT:
       UNREACHABLE();
       return;
   }