VectorICs: VisitClassLiteral needs adjustment for IC slot usage.

src/compiler/js-generic-lowering.cc

Index: src/compiler/js-generic-lowering.cc
diff --git a/src/compiler/js-generic-lowering.cc b/src/compiler/js-generic-lowering.cc
index 17b1597edbe0f3af9d0bf514849fbee45dac55af..ad783c1cbaa2851c7f9aee63415e2bde8a8ddd01 100644
--- a/src/compiler/js-generic-lowering.cc
+++ b/src/compiler/js-generic-lowering.cc
@@ -359,11 +359,22 @@ void JSGenericLowering::LowerJSStoreProperty(Node* node) {
   CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
   const StorePropertyParameters& p = StorePropertyParametersOf(node->op());
   LanguageMode language_mode = OpParameter<LanguageMode>(node);
-  Callable callable = CodeFactory::KeyedStoreICInOptimizedCode(
-      isolate(), language_mode, UNINITIALIZED);
+  InlineCacheState state = FLAG_vector_stores && p.feedback().index() == -1

[Michael Starzinger, 2015/07/24 11:51:30]

Can we restructure this a little to be more readable. I had a hard time
understanding it and would have come to the wrong conclusion without your
offline help. How about this ...

// We have a special case where we do keyed stores but don't have a type
// feedback vector slot allocated to support it. In this case, install
// the megamorphic keyed store stub which needs neither vector nor slot.
bool use_vector_slot = FLAG_vector_stores && p.feedback().index() != -1;
Callable callable = CodeFactory::KeyedStoreICInOptimizedCode(isolate(),
language_mode, use_vector_slot ? UNINITIALIZED : MEGAMORPHIC);
if (use_vector_slot) {
  node->InsertInput(zone(), 3, jsgraph()->SmiConstant(p.feedback().index()));
} else {
  node->RemoveInput(3);
}

[mvstanton, 2015/07/24 12:24:58]

Most wise, thanks!

+                               ? MEGAMORPHIC
+                               : UNINITIALIZED;
+  Callable callable =
+      CodeFactory::KeyedStoreICInOptimizedCode(isolate(), language_mode, state);
   if (FLAG_vector_stores) {
-    DCHECK(p.feedback().index() != -1);
-    node->InsertInput(zone(), 3, jsgraph()->SmiConstant(p.feedback().index()));
+    if (state == MEGAMORPHIC) {
+      // We have a special case where we do keyed stores but don't have a type
+      // feedback vector slot allocated to support it. In this case, install
+      // the megamorphic keyed store stub which needs neither vector nor slot.
+      node->RemoveInput(3);
+    } else {
+      DCHECK(p.feedback().index() != -1);
+      node->InsertInput(zone(), 3,
+                        jsgraph()->SmiConstant(p.feedback().index()));
+    }
   } else {
     node->RemoveInput(3);
   }