1 /*
   2  * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
   3  * Copyright 2008, 2009, 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 class ZeroStack {
  27  private:
  28   intptr_t *_base; // the last available word
  29   intptr_t *_top;  // the word past the end of the stack
  30   intptr_t *_sp;   // the top word on the stack
  31 
  32  private:
  33   int _shadow_pages_size; // how much ABI stack must we keep free?
  34 
  35  public:
  36   ZeroStack()
  37     : _base(NULL), _top(NULL), _sp(NULL) {
  38     _shadow_pages_size = StackShadowPages * os::vm_page_size();
  39   }
  40 
  41   bool needs_setup() const {
  42     return _base == NULL;
  43   }
  44 
  45   void setup(void *mem, size_t size) {
  46     assert(needs_setup(), "already set up");
  47     assert(!(size & WordAlignmentMask), "unaligned");
  48 
  49     _base = (intptr_t *) mem;
  50     _top  = _base + (size >> LogBytesPerWord);
  51     _sp   = _top;
  52   }
  53   void teardown() {
  54     assert(!needs_setup(), "not set up");
  55     assert(_sp == _top, "stuff on stack at teardown");
  56 
  57     _base = NULL;
  58     _top  = NULL;
  59     _sp   = NULL;
  60   }
  61 
  62   intptr_t *sp() const {
  63     return _sp;
  64   }
  65   void set_sp(intptr_t *new_sp) {
  66     assert(_top >= new_sp && new_sp >= _base, "bad stack pointer");
  67     _sp = new_sp;
  68   }
  69 
  70   int available_words() const {
  71     return _sp - _base;
  72   }
  73 
  74   void push(intptr_t value) {
  75     assert(_sp > _base, "stack overflow");
  76     *(--_sp) = value;
  77   }
  78   intptr_t pop() {
  79     assert(_sp < _top, "stack underflow");
  80     return *(_sp++);
  81   }
  82 
  83   void *alloc(size_t size) {
  84     int count = align_size_up(size, wordSize) >> LogBytesPerWord;
  85     assert(count <= available_words(), "stack overflow");
  86     return _sp -= count;
  87   }
  88 
  89   int shadow_pages_size() const {
  90     return _shadow_pages_size;
  91   }
  92 
  93  public:
  94   void overflow_check(int required_words, TRAPS);
  95   static void handle_overflow(TRAPS);
  96 
  97  public:
  98   static ByteSize base_offset() {
  99     return byte_offset_of(ZeroStack, _base);
 100   }
 101   static ByteSize top_offset() {
 102     return byte_offset_of(ZeroStack, _top);
 103   }
 104   static ByteSize sp_offset() {
 105     return byte_offset_of(ZeroStack, _sp);
 106   }
 107 };
 108 
 109 
 110 class EntryFrame;
 111 class InterpreterFrame;
 112 class SharkFrame;
 113 class FakeStubFrame;
 114 
 115 //
 116 // |  ...               |
 117 // +--------------------+  ------------------
 118 // |  ...               |       low addresses
 119 // | frame_type         |
 120 // | next_frame         |      high addresses
 121 // +--------------------+  ------------------
 122 // |  ...               |
 123 
 124 class ZeroFrame {
 125   friend class frame;
 126   friend class ZeroStackPrinter;
 127 
 128  protected:
 129   ZeroFrame() {
 130     ShouldNotCallThis();
 131   }
 132 
 133   enum Layout {
 134     next_frame_off,
 135     frame_type_off,
 136     jf_header_words
 137   };
 138 
 139   enum FrameType {
 140     ENTRY_FRAME = 1,
 141     INTERPRETER_FRAME,
 142     SHARK_FRAME,
 143     FAKE_STUB_FRAME
 144   };
 145 
 146  protected:
 147   intptr_t *addr_of_word(int offset) const {
 148     return (intptr_t *) this - offset;
 149   }
 150   intptr_t value_of_word(int offset) const {
 151     return *addr_of_word(offset);
 152   }
 153 
 154  public:
 155   ZeroFrame *next() const {
 156     return (ZeroFrame *) value_of_word(next_frame_off);
 157   }
 158 
 159  protected:
 160   FrameType type() const {
 161     return (FrameType) value_of_word(frame_type_off);
 162   }
 163 
 164  public:
 165   bool is_entry_frame() const {
 166     return type() == ENTRY_FRAME;
 167   }
 168   bool is_interpreter_frame() const {
 169     return type() == INTERPRETER_FRAME;
 170   }
 171   bool is_shark_frame() const {
 172     return type() == SHARK_FRAME;
 173   }
 174   bool is_fake_stub_frame() const {
 175     return type() == FAKE_STUB_FRAME;
 176   }
 177 
 178  public:
 179   EntryFrame *as_entry_frame() const {
 180     assert(is_entry_frame(), "should be");
 181     return (EntryFrame *) this;
 182   }
 183   InterpreterFrame *as_interpreter_frame() const {
 184     assert(is_interpreter_frame(), "should be");
 185     return (InterpreterFrame *) this;
 186   }
 187   SharkFrame *as_shark_frame() const {
 188     assert(is_shark_frame(), "should be");
 189     return (SharkFrame *) this;
 190   }
 191   FakeStubFrame *as_fake_stub_frame() const {
 192     assert(is_fake_stub_frame(), "should be");
 193     return (FakeStubFrame *) this;
 194   }
 195 
 196  public:
 197   void identify_word(int   frame_index,
 198                      int   offset,
 199                      char* fieldbuf,
 200                      char* valuebuf,
 201                      int   buflen) const;
 202 
 203  protected:
 204   void identify_vp_word(int       frame_index,
 205                         intptr_t* addr,
 206                         intptr_t* monitor_base,
 207                         intptr_t* stack_base,
 208                         char*     fieldbuf,
 209                         int       buflen) const;
 210 };