1 /*
   2  * Copyright 2003-2005 Sun Microsystems, Inc.  All Rights Reserved.
   3  * Copyright 2007, 2008, 2010 Red Hat, Inc.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  */
  25 
  26  private:
  27   ZeroFrame* volatile _last_Java_fp;
  28 
  29  public:
  30   // Each arch must define reset, save, restore
  31   // These are used by objects that only care about:
  32   //  1 - initializing a new state (thread creation, javaCalls)
  33   //  2 - saving a current state (javaCalls)
  34   //  3 - restoring an old state (javaCalls)
  35   // Note that whenever _last_Java_sp != NULL other anchor fields
  36   // must be valid.  The profiler apparently depends on this.
  37 
  38   void clear() {
  39     // clearing _last_Java_sp must be first
  40     _last_Java_sp = NULL;
  41     // fence?
  42     _last_Java_fp = NULL;
  43     _last_Java_pc = NULL;
  44   }
  45 
  46   void copy(JavaFrameAnchor* src) {
  47     set(src->_last_Java_sp, src->_last_Java_pc, src->_last_Java_fp);
  48   }
  49 
  50   void set(intptr_t* sp, address pc, ZeroFrame* fp) {
  51     // In order to make sure the transition state is valid for "this"
  52     // We must clear _last_Java_sp before copying the rest of the new
  53     // data
  54     //
  55     // Hack Alert: Temporary bugfix for 4717480/4721647 To act like
  56     // previous version (pd_cache_state) don't NULL _last_Java_sp
  57     // unless the value is changing
  58     //
  59     if (_last_Java_sp != sp)
  60       _last_Java_sp = NULL;
  61 
  62     _last_Java_fp = fp;
  63     _last_Java_pc = pc;
  64     // Must be last so profiler will always see valid frame if
  65     // has_last_frame() is true
  66     _last_Java_sp = sp;
  67   }
  68 
  69   bool walkable() {
  70     return true;
  71   }
  72 
  73   void make_walkable(JavaThread* thread) {
  74     // nothing to do
  75   }
  76 
  77   intptr_t* last_Java_sp() const {
  78     return _last_Java_sp;
  79   }
  80 
  81   ZeroFrame* last_Java_fp() const {
  82     return _last_Java_fp;
  83   }