Track field types.

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index 28f4028c525946a809eef6f49b24abb7b9a95a70..23f38d50f00dfdd7437faaebb727410daf183f4d 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -528,7 +528,12 @@ 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(), miss_label, DO_SMI_CHECK);
+    } else {
+      __ JumpIfSmi(value_reg, miss_label);
+    }
   } else if (representation.IsDouble()) {
     Label do_store, heap_number;
     __ AllocateHeapNumber(storage_reg, scratch1, scratch2, slow);
@@ -698,7 +703,12 @@ 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(), miss_label, DO_SMI_CHECK);
+    } else {
+      __ JumpIfSmi(value_reg, miss_label);
+    }
   } else if (representation.IsDouble()) {
     // Load the double storage.
     if (index < 0) {