1 /*
   2  * Copyright (c) 2002, 2005, 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   volatile int _flags;
  27 
  28 public:
  29 
  30    enum pd_Constants {
  31      flushed = 1                                 // winodows have flushed
  32    };
  33 
  34   int flags(void)                                { return _flags; }
  35   void set_flags(int flags)                      { _flags = flags; }
  36 
  37   static ByteSize flags_offset()                 { return byte_offset_of(JavaFrameAnchor, _flags); }
  38 
  39   // Each arch must define clear, copy
  40   // These are used by objects that only care about:
  41   //  1 - initializing a new state (thread creation, javaCalls)
  42   //  2 - saving a current state (javaCalls)
  43   //  3 - restoring an old state (javaCalls)
  44 
  45   void clear(void) {
  46     // clearing _last_Java_sp must be first
  47     _last_Java_sp = NULL;
  48     // fence?
  49     _flags = 0;
  50     _last_Java_pc = NULL;
  51   }
  52 
  53   void copy(JavaFrameAnchor* src) {
  54     // In order to make sure the transition state is valid for "this"
  55     // We must clear _last_Java_sp before copying the rest of the new data
  56     //
  57     // Hack Alert: Temporary bugfix for 4717480/4721647
  58     // To act like previous version (pd_cache_state) don't NULL _last_Java_sp
  59     // unless the value is changing
  60     //
  61     if (_last_Java_sp != src->_last_Java_sp)
  62       _last_Java_sp = NULL;
  63 
  64     _flags = src->_flags;
  65     _last_Java_pc = src->_last_Java_pc;
  66     // Must be last so profiler will always see valid frame if has_last_frame() is true
  67     _last_Java_sp = src->_last_Java_sp;
  68   }
  69 
  70   // Is stack walkable
  71   inline bool walkable( void) {
  72         return _flags & flushed;
  73   }
  74 
  75   void make_walkable(JavaThread* thread);
  76 
  77   void set_last_Java_sp(intptr_t* sp)            { _last_Java_sp = sp; }
  78 
  79   address last_Java_pc(void)                     { return _last_Java_pc; }
  80 
  81   // These are only used by friends
  82 private:
  83 
  84   intptr_t* last_Java_sp() const {
  85     // _last_Java_sp will always be a an unbiased stack pointer
  86     // if is is biased then some setter screwed up. This is
  87     // deadly.
  88 #ifdef _LP64
  89     assert(((intptr_t)_last_Java_sp & 0xF) == 0, "Biased last_Java_sp");
  90 #endif
  91     return _last_Java_sp;
  92   }
  93 
  94   void capture_last_Java_pc(intptr_t* sp);
  95 
  96   void set_window_flushed( void) {
  97     _flags |= flushed;
  98     OrderAccess::fence();
  99   }