Vector ICs: ClassLiterals need to allocate a vector slot for home objects.

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 616ac5a8cb98e88307b9104c768e769e971cbdf4..73b06631e49c8312ed4435a59735222a0a3ad017 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -2705,6 +2705,28 @@ class ClassLiteral final : public Expression {
   // ClassLiteral can vary, so num_ids() is not a static method.
   int num_ids() const { return parent_num_ids() + 4 + properties()->length(); }
 
+  // Object literals need one feedback slot for each non-trivial value, as well
+  // as some slots for home objects.
+  FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate, const ICSlotCache* cache) override;
+  void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot,
+                              ICSlotCache* cache) override {
+    slot_ = slot;
+  }
+  Code::Kind FeedbackICSlotKind(int index) override { return Code::STORE_IC; }
+  FeedbackVectorICSlot GetNthSlot(int n) const {
+    return FeedbackVectorICSlot(slot_.ToInt() + n);
+  }
+
+  // If value needs a home object, returns a valid feedback vector ic slot
+  // given by slot_index, and increments slot_index.
+  FeedbackVectorICSlot SlotForHomeObject(Expression* value,
+                                         int* slot_index) const;
+
+#ifdef DEBUG
+  int slot_count() const { return slot_count_; }
+#endif
+
  protected:
   ClassLiteral(Zone* zone, const AstRawString* name, Scope* scope,
                VariableProxy* class_variable_proxy, Expression* extends,
@@ -2717,7 +2739,13 @@ class ClassLiteral final : public Expression {
         extends_(extends),
         constructor_(constructor),
         properties_(properties),
-        end_position_(end_position) {}
+        end_position_(end_position),
+#ifdef DEBUG
+        slot_count_(0),
+#endif
+        slot_(FeedbackVectorICSlot::Invalid()) {
+  }
+
   static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
@@ -2730,6 +2758,12 @@ class ClassLiteral final : public Expression {
   FunctionLiteral* constructor_;
   ZoneList<Property*>* properties_;
   int end_position_;
+#ifdef DEBUG
+  // slot_count_ helps validate that the logic to allocate ic slots and the
+  // logic to use them are in sync.
+  int slot_count_;
+#endif
+  FeedbackVectorICSlot slot_;
 };