1 /*
   2  * Copyright (c) 2002, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 private:
  26 
  27   // FP value associated with _last_Java_sp:
  28   intptr_t* volatile        _last_Java_fp;           // pointer is volatile not what it points to
  29 
  30 public:
  31   // Each arch must define reset, save, restore
  32   // These are used by objects that only care about:
  33   //  1 - initializing a new state (thread creation, javaCalls)
  34   //  2 - saving a current state (javaCalls)
  35   //  3 - restoring an old state (javaCalls)
  36 
  37   void clear(void) {
  38     // clearing _last_Java_sp must be first
  39     _last_Java_sp = NULL;
  40     // fence?
  41     _last_Java_fp = NULL;
  42     _last_Java_pc = NULL;
  43   }
  44 
  45   void copy(JavaFrameAnchor* src) {
  46     // In order to make sure the transition state is valid for "this"
  47     // We must clear _last_Java_sp before copying the rest of the new data
  48     //
  49     // Hack Alert: Temporary bugfix for 4717480/4721647
  50     // To act like previous version (pd_cache_state) don't NULL _last_Java_sp
  51     // unless the value is changing
  52     //
  53     if (_last_Java_sp != src->_last_Java_sp)
  54       _last_Java_sp = NULL;
  55 
  56     _last_Java_fp = src->_last_Java_fp;
  57     _last_Java_pc = src->_last_Java_pc;
  58     // Must be last so profiler will always see valid frame if has_last_frame() is true
  59     _last_Java_sp = src->_last_Java_sp;
  60   }
  61 
  62   // Always walkable
  63   bool walkable(void) { return true; }
  64   // Never any thing to do since we are always walkable and can find address of return addresses
  65   void make_walkable(JavaThread* thread) { }
  66 
  67   intptr_t* last_Java_sp(void) const             { return _last_Java_sp; }
  68 
  69   address last_Java_pc(void)                     { return _last_Java_pc; }
  70 
  71 private:
  72 
  73   static ByteSize last_Java_fp_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_fp); }
  74 
  75 public:
  76 
  77   void set_last_Java_sp(intptr_t* sp)            { _last_Java_sp = sp; }
  78 
  79   intptr_t*   last_Java_fp(void)                     { return _last_Java_fp; }
  80   // Assert (last_Java_sp == NULL || fp == NULL)
  81   void set_last_Java_fp(intptr_t* fp)                { _last_Java_fp = fp; }