Track up to 5 stable maps as field type.

src/x64/stub-cache-x64.cc

Index: src/x64/stub-cache-x64.cc
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 0981114ec404c100760795ba8ae82c403f33bba3..93121a05ca89e2d43b8f9ca218fc4756e954b626 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -494,13 +494,21 @@ void StoreStubCompiler::GenerateStoreTransition(MacroAssembler* masm,
   } else if (representation.IsSmi()) {
     __ JumpIfNotSmi(value_reg, miss_label);
   } else if (representation.IsHeapObject()) {
+    __ JumpIfSmi(value_reg, miss_label);
     HeapType* field_type = descriptors->GetFieldType(descriptor);
-    if (field_type->IsClass()) {
-      __ CheckMap(value_reg, field_type->AsClass()->Map(),
-                  miss_label, DO_SMI_CHECK);
-    } else {
-      ASSERT(HeapType::Any()->Is(field_type));
-      __ JumpIfSmi(value_reg, miss_label);
+    HeapType::Iterator<Map> it = field_type->Classes();
+    if (!it.Done()) {
+      Label do_store;
+      while (true) {
+        __ CompareMap(value_reg, it.Current());
+        it.Advance();
+        if (it.Done()) {
+          __ j(not_equal, miss_label);
+          break;
+        }
+        __ j(equal, &do_store, Label::kNear);
+      }
+      __ bind(&do_store);
     }
   } else if (representation.IsDouble()) {
     Label do_store, heap_number;
@@ -645,13 +653,21 @@ void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
   if (representation.IsSmi()) {
     __ JumpIfNotSmi(value_reg, miss_label);
   } else if (representation.IsHeapObject()) {
+    __ JumpIfSmi(value_reg, miss_label);
     HeapType* field_type = lookup->GetFieldType();
-    if (field_type->IsClass()) {
-      __ CheckMap(value_reg, field_type->AsClass()->Map(),
-                  miss_label, DO_SMI_CHECK);
-    } else {
-      ASSERT(HeapType::Any()->Is(field_type));
-      __ JumpIfSmi(value_reg, miss_label);
+    HeapType::Iterator<Map> it = field_type->Classes();
+    if (!it.Done()) {
+      Label do_store;
+      while (true) {
+        __ CompareMap(value_reg, it.Current());
+        it.Advance();
+        if (it.Done()) {
+          __ j(not_equal, miss_label);
+          break;
+        }
+        __ j(equal, &do_store, Label::kNear);
+      }
+      __ bind(&do_store);
     }
   } else if (representation.IsDouble()) {
     // Load the double storage.