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

src/arm64/full-codegen-arm64.cc

Index: src/arm64/full-codegen-arm64.cc
diff --git a/src/arm64/full-codegen-arm64.cc b/src/arm64/full-codegen-arm64.cc
index 42254d6271d0783fbe771d444ad6f67b4224d6b9..fa79cfd012238e122e707a28af23ff626ae496d9 100644
--- a/src/arm64/full-codegen-arm64.cc
+++ b/src/arm64/full-codegen-arm64.cc
@@ -2255,6 +2255,10 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
          FieldMemOperand(x0, JSFunction::kPrototypeOrInitialMapOffset));
   __ Push(scratch);
 
+  // store_slot_index points to the vector ic slot for the next store ic used.
+  // ClassLiteral::ComputeFeedbackRequirements controls the allocation of slots
+  // and must be updated if the number of store ics emitted here changes.
+  int store_slot_index = 0;
   for (int i = 0; i < lit->properties()->length(); i++) {
     ObjectLiteral::Property* property = lit->properties()->at(i);
     Expression* value = property->value();
@@ -2277,7 +2281,8 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
     }
 
     VisitForStackValue(value);
-    EmitSetHomeObjectIfNeeded(value, 2);
+    EmitSetHomeObjectIfNeeded(value, 2,
+                              lit->SlotForHomeObject(value, &store_slot_index));
 
     switch (property->kind()) {
       case ObjectLiteral::Property::CONSTANT:
@@ -2310,6 +2315,10 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
 
   // constructor
   __ CallRuntime(Runtime::kToFastProperties, 1);
+
+  // Verify that compilation exactly consumed the number of store ic slots that
+  // the ClassLiteral node had to offer.
+  DCHECK(!FLAG_vector_stores || store_slot_index == lit->slot_count());
 }