/*

 * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.

 * Copyright 2008, 2009, 2010 Red Hat, Inc.

 * 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.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

class ZeroStack {

 private:

  intptr_t *_base; // the last available word

  intptr_t *_top;  // the word past the end of the stack

  intptr_t *_sp;   // the top word on the stack

 private:

  int _shadow_pages_size; // how much ABI stack must we keep free?

 public:

  ZeroStack()

    : _base(NULL), _top(NULL), _sp(NULL) {

    _shadow_pages_size = StackShadowPages * os::vm_page_size();

  }

  bool needs_setup() const {

    return _base == NULL;

  }

  void setup(void *mem, size_t size) {

    assert(needs_setup(), "already set up");

    assert(!(size & WordAlignmentMask), "unaligned");

    _base = (intptr_t *) mem;

    _top  = _base + (size >> LogBytesPerWord);

    _sp   = _top;

  }

  void teardown() {

    assert(!needs_setup(), "not set up");

    assert(_sp == _top, "stuff on stack at teardown");

    _base = NULL;

    _top  = NULL;

    _sp   = NULL;

  }

  intptr_t *sp() const {

    return _sp;

  }

  void set_sp(intptr_t *new_sp) {

    assert(_top >= new_sp && new_sp >= _base, "bad stack pointer");

    _sp = new_sp;

  }

  int available_words() const {

    return _sp - _base;

  }

  void push(intptr_t value) {

    assert(_sp > _base, "stack overflow");

    *(--_sp) = value;

  }

  intptr_t pop() {

    assert(_sp < _top, "stack underflow");

    return *(_sp++);

  }

  void *alloc(size_t size) {

    int count = align_size_up(size, wordSize) >> LogBytesPerWord;

    assert(count <= available_words(), "stack overflow");

    return _sp -= count;

  }

  int shadow_pages_size() const {

    return _shadow_pages_size;

  }

 public:

  void overflow_check(int required_words, TRAPS);

  static void handle_overflow(TRAPS);

 public:

  void zap(int c) PRODUCT_RETURN;

 public:

  static ByteSize base_offset() {

    return byte_offset_of(ZeroStack, _base);

  }

  static ByteSize top_offset() {

    return byte_offset_of(ZeroStack, _top);

  }

  static ByteSize sp_offset() {

    return byte_offset_of(ZeroStack, _sp);

  }

};

class EntryFrame;

class InterpreterFrame;

class SharkFrame;

class FakeStubFrame;

//

// |  ...               |

// +--------------------+  ------------------

// |  ...               |       low addresses

// | frame_type         |

// | next_frame         |      high addresses

// +--------------------+  ------------------

// |  ...               |

class ZeroFrame {

  friend class frame;

  friend class ZeroStackPrinter;

 protected:

  ZeroFrame() {

    ShouldNotCallThis();

  }

  enum Layout {

    next_frame_off,

    frame_type_off,

    jf_header_words

  };

  enum FrameType {

    ENTRY_FRAME = 1,

    INTERPRETER_FRAME,

    SHARK_FRAME,

    FAKE_STUB_FRAME

  };

 protected:

  intptr_t *addr_of_word(int offset) const {

    return (intptr_t *) this - offset;

  }

  intptr_t value_of_word(int offset) const {

    return *addr_of_word(offset);

  }

 public:

  ZeroFrame *next() const {

    return (ZeroFrame *) value_of_word(next_frame_off);

  }

 protected:

  FrameType type() const {

    return (FrameType) value_of_word(frame_type_off);

  }

 public:

  bool is_entry_frame() const {

    return type() == ENTRY_FRAME;

  }

  bool is_interpreter_frame() const {

    return type() == INTERPRETER_FRAME;

  }

  bool is_shark_frame() const {

    return type() == SHARK_FRAME;

  }

  bool is_fake_stub_frame() const {

    return type() == FAKE_STUB_FRAME;

  }

 public:

  EntryFrame *as_entry_frame() const {

    assert(is_entry_frame(), "should be");

    return (EntryFrame *) this;

  }

  InterpreterFrame *as_interpreter_frame() const {

    assert(is_interpreter_frame(), "should be");

    return (InterpreterFrame *) this;

  }

  SharkFrame *as_shark_frame() const {

    assert(is_shark_frame(), "should be");

    return (SharkFrame *) this;

  }

  FakeStubFrame *as_fake_stub_frame() const {

    assert(is_fake_stub_frame(), "should be");

    return (FakeStubFrame *) this;

  }

 public:

  void identify_word(int   frame_index,

                     int   offset,

                     char* fieldbuf,

                     char* valuebuf,

                     int   buflen) const;

 protected:

  void identify_vp_word(int       frame_index,

                        intptr_t* addr,

                        intptr_t* monitor_base,

                        intptr_t* stack_base,

                        char*     fieldbuf,

                        int       buflen) const;

};