--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/oops/fieldInfo.hpp	Sat Dec 17 21:40:27 2011 +0100
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_OOPS_FIELDINFO_HPP
+#define SHARE_VM_OOPS_FIELDINFO_HPP
+
+#include "oops/typeArrayOop.hpp"
+#include "classfile/vmSymbols.hpp"
+
+// This class represents the field information contained in the fields
+// array of an instanceKlass.  Currently it's laid on top an array of
+// Java shorts but in the future it could simply be used as a real
+// array type.  FieldInfo generally shouldn't be used directly.
+// Fields should be queried either through instanceKlass or through
+// the various FieldStreams.
+class FieldInfo VALUE_OBJ_CLASS_SPEC {
+  friend class fieldDescriptor;
+  friend class JavaFieldStream;
+  friend class ClassFileParser;
+
+ public:
+  // fields
+  // Field info extracted from the class file and stored
+  // as an array of 7 shorts
+  enum FieldOffset {
+    access_flags_offset      = 0,
+    name_index_offset        = 1,
+    signature_index_offset   = 2,
+    initval_index_offset     = 3,
+    low_offset               = 4,
+    high_offset              = 5,
+    generic_signature_offset = 6,
+    field_slots              = 7
+  };
+
+ private:
+  u2 _shorts[field_slots];
+
+  void set_name_index(u2 val)                    { _shorts[name_index_offset] = val;         }
+  void set_signature_index(u2 val)               { _shorts[signature_index_offset] = val;    }
+  void set_initval_index(u2 val)                 { _shorts[initval_index_offset] = val;      }
+  void set_generic_signature_index(u2 val)       { _shorts[generic_signature_offset] = val;  }
+
+  u2 name_index() const                          { return _shorts[name_index_offset];        }
+  u2 signature_index() const                     { return _shorts[signature_index_offset];   }
+  u2 initval_index() const                       { return _shorts[initval_index_offset];     }
+  u2 generic_signature_index() const             { return _shorts[generic_signature_offset]; }
+
+ public:
+  static FieldInfo* from_field_array(typeArrayOop fields, int index) {
+    return ((FieldInfo*)fields->short_at_addr(index * field_slots));
+  }
+
+  void initialize(u2 access_flags,
+                  u2 name_index,
+                  u2 signature_index,
+                  u2 initval_index,
+                  u2 generic_signature_index,
+                  u4 offset) {
+    _shorts[access_flags_offset] = access_flags;
+    _shorts[name_index_offset] = name_index;
+    _shorts[signature_index_offset] = signature_index;
+    _shorts[initval_index_offset] = initval_index;
+    _shorts[generic_signature_offset] = generic_signature_index;
+    set_offset(offset);
+  }
+
+  u2 access_flags() const                        { return _shorts[access_flags_offset];            }
+  u4 offset() const                              { return build_int_from_shorts(_shorts[low_offset], _shorts[high_offset]); }
+
+  Symbol* name(constantPoolHandle cp) const {
+    int index = name_index();
+    if (is_internal()) {
+      return lookup_symbol(index);
+    }
+    return cp->symbol_at(index);
+  }
+
+  Symbol* signature(constantPoolHandle cp) const {
+    int index = signature_index();
+    if (is_internal()) {
+      return lookup_symbol(index);
+    }
+    return cp->symbol_at(index);
+  }
+
+  Symbol* generic_signature(constantPoolHandle cp) const {
+    int index = generic_signature_index();
+    if (index == 0) {
+      return NULL;
+    }
+    return cp->symbol_at(index);
+  }
+
+  void set_access_flags(u2 val)                  { _shorts[access_flags_offset] = val;             }
+  void set_offset(u4 val)                        {
+    _shorts[low_offset] = extract_low_short_from_int(val);
+    _shorts[high_offset] = extract_high_short_from_int(val);
+  }
+
+  bool is_internal() const {
+    return (access_flags() & JVM_ACC_FIELD_INTERNAL) != 0;
+  }
+
+  Symbol* lookup_symbol(int symbol_index) const {
+    assert(is_internal(), "only internal fields");
+    return vmSymbols::symbol_at((vmSymbols::SID)symbol_index);
+  }
+};
+
+#endif // SHARE_VM_OOPS_FIELDINFO_HPP