Merge bleeding edge up to 8774 into the GC branch.

src/utils.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_UTILS_H_
 #define V8_UTILS_H_
 
 #include <stdlib.h>
 #include <string.h>
+#include <climits>
 
 #include "globals.h"
 #include "checks.h"
 #include "allocation.h"
 
 namespace v8 {
 namespace internal {
 
 // ----------------------------------------------------------------------------
 // General helper functions
@@ skipping 841 matching lines @@
 
  protected:
   Vector<char> buffer_;
   int position_;
 
   bool is_finalized() const { return position_ < 0; }
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(SimpleStringBuilder);
 };
 
+
+// A poor man's version of STL's bitset: A bit set of enums E (without explicit
+// values), fitting into an integral type T.
+template <class E, class T = int>
+class EnumSet {
+ public:
+  explicit EnumSet(T bits = 0) : bits_(bits) {}
+  bool IsEmpty() const { return bits_ == 0; }
+  bool Contains(E element) const { return (bits_ & Mask(element)) != 0; }
+  void Add(E element) { bits_ |= Mask(element); }
+  void Remove(E element) { bits_ &= ~Mask(element); }
+  T ToIntegral() const { return bits_; }
+
+ private:
+  T Mask(E element) const {
+    // The strange typing in ASSERT is necessary to avoid stupid warnings, see:
+    // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43680
+    ASSERT(element < static_cast<int>(sizeof(T) * CHAR_BIT));
+    return 1 << element;
+  }
+
+  T bits_;
+};
+
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_