MIPS: Reland "Track field types.".

src/mips/stub-cache-mips.cc

Index: src/mips/stub-cache-mips.cc
diff --git a/src/mips/stub-cache-mips.cc b/src/mips/stub-cache-mips.cc
index 153a8168207121389892de1ec307edc1a6211e65..45aadc85a30b2ac470a95e23892af0f63d894bba 100644
--- a/src/mips/stub-cache-mips.cc
+++ b/src/mips/stub-cache-mips.cc
@@ -415,7 +415,14 @@ 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 {
+      ASSERT(HeapType::Any()->Is(field_type));
+      __ JumpIfSmi(value_reg, miss_label);
+    }
   } else if (representation.IsDouble()) {
     Label do_store, heap_number;
     __ LoadRoot(scratch3, Heap::kHeapNumberMapRootIndex);
@@ -578,7 +585,14 @@ 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 {
+      ASSERT(HeapType::Any()->Is(field_type));
+      __ JumpIfSmi(value_reg, miss_label);
+    }
   } else if (representation.IsDouble()) {
     // Load the double storage.
     if (index < 0) {