Track field types.

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
diff --git a/src/arm/stub-cache-arm.cc b/src/arm/stub-cache-arm.cc
index c595e427458c711c182e78a86f51bdc72b3036d2..3333690d3e0b65a6754415ca10601b54f196afe8 100644
--- a/src/arm/stub-cache-arm.cc
+++ b/src/arm/stub-cache-arm.cc
@@ -430,7 +430,13 @@ 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, scratch1, field_type->AsClass(),
+                  miss_label, DO_SMI_CHECK);
+    } else {
+      __ JumpIfSmi(value_reg, miss_label);
+    }
   } else if (representation.IsDouble()) {
     Label do_store, heap_number;
     __ LoadRoot(scratch3, Heap::kHeapNumberMapRootIndex);
@@ -592,7 +598,13 @@ 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, scratch1, 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) {