src/share/vm/oops/klass.inline.hpp

*** 1,7 ****
  /*
!  * Copyright (c) 2005, 2010, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2005, 2013, 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.
*** 23,36 ****
--- 23,74 ----
   */
  
  #ifndef SHARE_VM_OOPS_KLASS_INLINE_HPP
  #define SHARE_VM_OOPS_KLASS_INLINE_HPP
  
+ #include "memory/universe.hpp"
  #include "oops/klass.hpp"
  #include "oops/markOop.hpp"
  
  inline void Klass::set_prototype_header(markOop header) {
    assert(!header->has_bias_pattern() || oop_is_instance(), "biased locking currently only supported for Java instances");
    _prototype_header = header;
  }
  
+ inline bool Klass::is_null(Klass* obj)  { return obj == NULL; }
+ inline bool Klass::is_null(narrowKlass obj) { return obj == 0; }
+ 
+ // Encoding and decoding for klass field.
+ 
+ inline bool check_klass_alignment(Klass* obj) {
+   return (intptr_t)obj % KlassAlignmentInBytes == 0;
+ }
+ 
+ inline narrowKlass Klass::encode_klass_not_null(Klass* v) {
+   assert(!is_null(v), "klass value can never be zero");
+   assert(check_klass_alignment(v), "Address not aligned");
+   int    shift = Universe::narrow_klass_shift();
+   uint64_t pd = (uint64_t)(pointer_delta((void*)v, Universe::narrow_klass_base(), 1));
+   assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
+   uint64_t result = pd >> shift;
+   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
+   assert(decode_klass(result) == v, "reversibility");
+   return (narrowKlass)result;
+ }
+ 
+ inline narrowKlass Klass::encode_klass(Klass* v) {
+   return is_null(v) ? (narrowKlass)0 : encode_klass_not_null(v);
+ }
+ 
+ inline Klass* Klass::decode_klass_not_null(narrowKlass v) {
+   assert(!is_null(v), "narrow klass value can never be zero");
+   int    shift = Universe::narrow_klass_shift();
+   Klass* result = (Klass*)(void*)((uintptr_t)Universe::narrow_klass_base() + ((uintptr_t)v << shift));
+   assert(check_klass_alignment(result), err_msg("address not aligned: " PTR_FORMAT, (void*) result));
+   return result;
+ }
+ 
+ inline Klass* Klass::decode_klass(narrowKlass v) {
+   return is_null(v) ? (Klass*)NULL : decode_klass_not_null(v);
+ }
+ 
  #endif // SHARE_VM_OOPS_KLASS_INLINE_HPP