Introduce FieldIndex to unify and abstract property/field offset

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 75533d1259e143cfd47c32f4e4027209d69e6183..9eb113cede43253aa7738657f86e8b74e67eb9c6 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -661,12 +661,7 @@ void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
   // checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
-  int index = lookup->GetFieldIndex().field_index();
-
-  // Adjust for the number of properties stored in the object. Even in the
-  // face of a transition we can use the old map here because the size of the
-  // object and the number of in-object properties is not going to change.
-  index -= object->map()->inobject_properties();
+  FieldIndex index = lookup->GetFieldIndex();
 
   Representation representation = lookup->representation();
   ASSERT(!representation.IsNone());
@@ -691,13 +686,11 @@ void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
     }
   } else if (representation.IsDouble()) {
     // Load the double storage.
-    if (index < 0) {
-      int offset = object->map()->instance_size() + (index * kPointerSize);
-      __ mov(scratch1, FieldOperand(receiver_reg, offset));
+    if (index.is_inobject()) {
+      __ mov(scratch1, FieldOperand(receiver_reg, index.offset()));
     } else {
       __ mov(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));
-      int offset = index * kPointerSize + FixedArray::kHeaderSize;
-      __ mov(scratch1, FieldOperand(scratch1, offset));
+      __ mov(scratch1, FieldOperand(scratch1, index.offset()));
     }
 
     // Store the value into the storage.
@@ -723,17 +716,16 @@ void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
   // TODO(verwaest): Share this code as a code stub.
   SmiCheck smi_check = representation.IsTagged()
       ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;
-  if (index < 0) {
+  if (index.is_inobject()) {
     // Set the property straight into the object.
-    int offset = object->map()->instance_size() + (index * kPointerSize);
-    __ mov(FieldOperand(receiver_reg, offset), value_reg);
+    __ mov(FieldOperand(receiver_reg, index.offset()), value_reg);
 
     if (!representation.IsSmi()) {
       // Update the write barrier for the array address.
       // Pass the value being stored in the now unused name_reg.
       __ mov(name_reg, value_reg);
       __ RecordWriteField(receiver_reg,
-                          offset,
+                          index.offset(),
                           name_reg,
                           scratch1,
                           kDontSaveFPRegs,
@@ -742,17 +734,16 @@ void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
     }
   } else {
     // Write to the properties array.
-    int offset = index * kPointerSize + FixedArray::kHeaderSize;
     // Get the properties array (optimistically).
     __ mov(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));
-    __ mov(FieldOperand(scratch1, offset), value_reg);
+    __ mov(FieldOperand(scratch1, index.offset()), value_reg);
 
     if (!representation.IsSmi()) {
       // Update the write barrier for the array address.
       // Pass the value being stored in the now unused name_reg.
       __ mov(name_reg, value_reg);
       __ RecordWriteField(scratch1,
-                          offset,
+                          index.offset(),
                           name_reg,
                           receiver_reg,
                           kDontSaveFPRegs,
@@ -972,20 +963,14 @@ Register LoadStubCompiler::CallbackHandlerFrontend(
 
 void LoadStubCompiler::GenerateLoadField(Register reg,
                                          Handle<JSObject> holder,
-                                         PropertyIndex field,
+                                         FieldIndex field,
                                          Representation representation) {
   if (!reg.is(receiver())) __ mov(receiver(), reg);
   if (kind() == Code::LOAD_IC) {
-    LoadFieldStub stub(isolate(),
-                       field.is_inobject(holder),
-                       field.translate(holder),
-                       representation);
+    LoadFieldStub stub(isolate(), field);
     GenerateTailCall(masm(), stub.GetCode());
   } else {
-    KeyedLoadFieldStub stub(isolate(),
-                            field.is_inobject(holder),
-                            field.translate(holder),
-                            representation);
+    KeyedLoadFieldStub stub(isolate(), field);
     GenerateTailCall(masm(), stub.GetCode());
   }
 }