[KeyedLoadIC] Support Smi "handlers" for simple field loads

src/field-index.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_FIELD_INDEX_H_
 #define V8_FIELD_INDEX_H_
 
 #include "src/property-details.h"
 #include "src/utils.h"
 
@@ skipping 58 matching lines @@
     return result;
   }
 
   int GetKeyedLookupCacheIndex() const;
 
   int GetFieldAccessStubKey() const {
     return bit_field_ &
         (IsInObjectBits::kMask | IsDoubleBits::kMask | IndexBits::kMask);
   }
 
+  // For GetLoadByFieldOffset.
+  class FieldOffsetIsInobject : public BitField<bool, 1, 1> {};
+  class FieldOffsetIsDouble : public BitField<bool, 2, 1> {};
+  class FieldOffsetOffset : public BitField<int, 3, 27> {};
+  // Make sure we don't overflow into the sign bit.
+  STATIC_ASSERT(FieldOffsetOffset::kNext <= kSmiValueSize - 1);
+
  private:
   FieldIndex(bool is_inobject, int local_index, bool is_double,
              int inobject_properties, int first_inobject_property_offset,
              bool is_hidden = false) {
     DCHECK((first_inobject_property_offset & (kPointerSize - 1)) == 0);
     bit_field_ = IsInObjectBits::encode(is_inobject) |
       IsDoubleBits::encode(is_double) |
       FirstInobjectPropertyOffsetBits::encode(first_inobject_property_offset) |
       IsHiddenField::encode(is_hidden) |
       IndexBits::encode(local_index) |
@@ skipping 23 matching lines @@
       : public BitField<bool, FirstInobjectPropertyOffsetBits::kNext, 1> {};
   STATIC_ASSERT(IsHiddenField::kNext <= 32);
 
   int bit_field_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif