Replace C++ bitfields with our own BitFields

src/profile-generator.h

 // Copyright 2011 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_PROFILE_GENERATOR_H_
 #define V8_PROFILE_GENERATOR_H_
 
 #include "include/v8-profiler.h"
 #include "src/allocation.h"
 #include "src/hashmap.h"
@@ skipping 37 matching lines @@
  public:
   // CodeEntry doesn't own name strings, just references them.
   inline CodeEntry(Logger::LogEventsAndTags tag,
                    const char* name,
                    const char* name_prefix = CodeEntry::kEmptyNamePrefix,
                    const char* resource_name = CodeEntry::kEmptyResourceName,
                    int line_number = v8::CpuProfileNode::kNoLineNumberInfo,
                    int column_number = v8::CpuProfileNode::kNoColumnNumberInfo);
   ~CodeEntry();
 
-  bool is_js_function() const { return is_js_function_tag(tag_); }
+  bool is_js_function() const { return is_js_function_tag(tag()); }
   const char* name_prefix() const { return name_prefix_; }
   bool has_name_prefix() const { return name_prefix_[0] != '\0'; }
   const char* name() const { return name_; }
   const char* resource_name() const { return resource_name_; }
   int line_number() const { return line_number_; }
   int column_number() const { return column_number_; }
   void set_shared_id(int shared_id) { shared_id_ = shared_id; }
   int script_id() const { return script_id_; }
   void set_script_id(int script_id) { script_id_ = script_id; }
   void set_bailout_reason(const char* bailout_reason) {
     bailout_reason_ = bailout_reason;
   }
   const char* bailout_reason() const { return bailout_reason_; }
 
   static inline bool is_js_function_tag(Logger::LogEventsAndTags tag);
 
   List<OffsetRange>* no_frame_ranges() const { return no_frame_ranges_; }
   void set_no_frame_ranges(List<OffsetRange>* ranges) {
     no_frame_ranges_ = ranges;
   }
 
   void SetBuiltinId(Builtins::Name id);
-  Builtins::Name builtin_id() const { return builtin_id_; }
+  Builtins::Name builtin_id() const {
+    return BuiltinIdField::decode(bit_field_);
+  }
 
   uint32_t GetCallUid() const;
   bool IsSameAs(CodeEntry* entry) const;
 
   static const char* const kEmptyNamePrefix;
   static const char* const kEmptyResourceName;
   static const char* const kEmptyBailoutReason;
 
  private:
-  Logger::LogEventsAndTags tag_ : 8;
-  Builtins::Name builtin_id_ : 8;

[brucedawson, 2014/11/05 01:33:18]

Could presumably use typed enums (unsigned char) and no bit fields.

+  class TagField : public BitField<Logger::LogEventsAndTags, 0, 8> {};
+  class BuiltinIdField : public BitField<Builtins::Name, 8, 8> {};
+  Logger::LogEventsAndTags tag() const { return TagField::decode(bit_field_); }
+
+  uint32_t bit_field_;
   const char* name_prefix_;
   const char* name_;
   const char* resource_name_;
   int line_number_;
   int column_number_;
   int shared_id_;
   int script_id_;
   List<OffsetRange>* no_frame_ranges_;
   const char* bailout_reason_;
 
@@ skipping 226 matching lines @@
   CodeEntry* gc_entry_;
   CodeEntry* unresolved_entry_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROFILE_GENERATOR_H_