/*

 * Copyright 1998-2008 Sun Microsystems, Inc.  All Rights Reserved.

 * 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.

 *

 */

// Interface for generating the frame map for compiled code.  A frame map

// describes for a specific pc whether each register and frame stack slot is:

//   Oop         - A GC root for current frame

//   Value       - Live non-oop, non-float value: int, either half of double

//   Dead        - Dead; can be Zapped for debugging

//   CalleeXX    - Callee saved; also describes which caller register is saved

//   DerivedXX   - A derived oop; original oop is described.

//

// OopMapValue describes a single OopMap entry

class frame;

class RegisterMap;

class DerivedPointerEntry;

class OopMapValue: public StackObj {

  friend class VMStructs;

private:

  short _value;

  int value() const                                 { return _value; }

  void set_value(int value)                         { _value = value; }

  short _content_reg;

public:

  // Constants

  enum { type_bits                = 5,

         register_bits            = BitsPerShort - type_bits };

  enum { type_shift               = 0,

         register_shift           = type_bits };

  enum { type_mask                = right_n_bits(type_bits),

         type_mask_in_place       = type_mask << type_shift,

         register_mask            = right_n_bits(register_bits),

         register_mask_in_place   = register_mask << register_shift };

  enum oop_types {              // must fit in type_bits

         unused_value =0,       // powers of 2, for masking OopMapStream

         oop_value = 1,

         value_value = 2,

         narrowoop_value = 4,

         callee_saved_value = 8,

         derived_oop_value= 16 };

  // Constructors

  OopMapValue () { set_value(0); set_content_reg(VMRegImpl::Bad()); }

  OopMapValue (VMReg reg, oop_types t) { set_reg_type(reg,t); }

  OopMapValue (VMReg reg, oop_types t, VMReg reg2) { set_reg_type(reg,t); set_content_reg(reg2); }

  OopMapValue (CompressedReadStream* stream) { read_from(stream); }

  // Archiving

  void write_on(CompressedWriteStream* stream) {

    stream->write_int(value());

    if(is_callee_saved() || is_derived_oop()) {

      stream->write_int(content_reg()->value());

    }

  }

  void read_from(CompressedReadStream* stream) {

    set_value(stream->read_int());

    if(is_callee_saved() || is_derived_oop()) {

      set_content_reg(VMRegImpl::as_VMReg(stream->read_int(), true));

    }

  }

  // Querying

  bool is_oop()               { return mask_bits(value(), type_mask_in_place) == oop_value; }

  bool is_value()             { return mask_bits(value(), type_mask_in_place) == value_value; }

  bool is_narrowoop()           { return mask_bits(value(), type_mask_in_place) == narrowoop_value; }

  bool is_callee_saved()      { return mask_bits(value(), type_mask_in_place) == callee_saved_value; }

  bool is_derived_oop()       { return mask_bits(value(), type_mask_in_place) == derived_oop_value; }

  void set_oop()              { set_value((value() & register_mask_in_place) | oop_value); }

  void set_value()            { set_value((value() & register_mask_in_place) | value_value); }

  void set_narrowoop()          { set_value((value() & register_mask_in_place) | narrowoop_value); }

  void set_callee_saved()     { set_value((value() & register_mask_in_place) | callee_saved_value); }

  void set_derived_oop()      { set_value((value() & register_mask_in_place) | derived_oop_value); }

  VMReg reg() const { return VMRegImpl::as_VMReg(mask_bits(value(), register_mask_in_place) >> register_shift); }

  oop_types type() const      { return (oop_types)mask_bits(value(), type_mask_in_place); }

  static bool legal_vm_reg_name(VMReg p) {

    return (p->value()  == (p->value() & register_mask));

  }

  void set_reg_type(VMReg p, oop_types t) {

    set_value((p->value() << register_shift) | t);

    assert(reg() == p, "sanity check" );

    assert(type() == t, "sanity check" );

  }

  VMReg content_reg() const       { return VMRegImpl::as_VMReg(_content_reg, true); }

  void set_content_reg(VMReg r)   { _content_reg = r->value(); }

  // Physical location queries

  bool is_register_loc()      { return reg()->is_reg(); }

  bool is_stack_loc()         { return reg()->is_stack(); }

  // Returns offset from sp.

  int stack_offset() {

    assert(is_stack_loc(), "must be stack location");

    return reg()->reg2stack();

  }

  void print_on(outputStream* st) const;

  void print() const { print_on(tty); }

};

class OopMap: public ResourceObj {

  friend class OopMapStream;

  friend class VMStructs;

 private:

  int  _pc_offset;

  int  _omv_count;

  int  _omv_data_size;

  unsigned char* _omv_data;

  CompressedWriteStream* _write_stream;

  debug_only( OopMapValue::oop_types* _locs_used; int _locs_length;)

  // Accessors

  unsigned char* omv_data() const             { return _omv_data; }

  void set_omv_data(unsigned char* value)     { _omv_data = value; }

  int omv_data_size() const                   { return _omv_data_size; }

  void set_omv_data_size(int value)           { _omv_data_size = value; }

  int omv_count() const                       { return _omv_count; }

  void set_omv_count(int value)               { _omv_count = value; }

  void increment_count()                      { _omv_count++; }

  CompressedWriteStream* write_stream() const { return _write_stream; }

  void set_write_stream(CompressedWriteStream* value) { _write_stream = value; }

 private:

  enum DeepCopyToken { _deep_copy_token };

  OopMap(DeepCopyToken, OopMap* source);  // used only by deep_copy

 public:

  OopMap(int frame_size, int arg_count);

  // pc-offset handling

  int offset() const     { return _pc_offset; }

  void set_offset(int o) { _pc_offset = o; }

  // Check to avoid double insertion

  debug_only(OopMapValue::oop_types locs_used( int indx ) { return _locs_used[indx]; })

  // Construction

  // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd

  // slots to hold 4-byte values like ints and floats in the LP64 build.

  void set_oop  ( VMReg local);

  void set_value( VMReg local);

  void set_narrowoop(VMReg local);

  void set_dead ( VMReg local);

  void set_callee_saved( VMReg local, VMReg caller_machine_register );

  void set_derived_oop ( VMReg local, VMReg derived_from_local_register );

  void set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional);

  int heap_size() const;

  void copy_to(address addr);

  OopMap* deep_copy();

  bool has_derived_pointer() const PRODUCT_RETURN0;

  bool legal_vm_reg_name(VMReg local) {

     return OopMapValue::legal_vm_reg_name(local);

  }

  // Printing

  void print_on(outputStream* st) const;

  void print() const { print_on(tty); }

};

class OopMapSet : public ResourceObj {

  friend class VMStructs;

 private:

  int _om_count;

  int _om_size;

  OopMap** _om_data;

  int om_count() const              { return _om_count; }

  void set_om_count(int value)      { _om_count = value; }

  void increment_count()            { _om_count++; }

  int om_size() const               { return _om_size; }

  void set_om_size(int value)       { _om_size = value; }

  OopMap** om_data() const          { return _om_data; }

  void set_om_data(OopMap** value)  { _om_data = value; }

  void grow_om_data();

  void set(int index,OopMap* value) { assert((index == 0) || ((index > 0) && (index < om_size())),"bad index"); _om_data[index] = value; }

 public:

  OopMapSet();

  // returns the number of OopMaps in this OopMapSet

  int size() const            { return _om_count; }

  // returns the OopMap at a given index

  OopMap* at(int index) const { assert((index >= 0) && (index <= om_count()),"bad index"); return _om_data[index]; }

  // Collect OopMaps.

  void add_gc_map(int pc, OopMap* map);

  // Returns the only oop map. Used for reconstructing

  // Adapter frames during deoptimization

  OopMap* singular_oop_map();

  // returns OopMap in that is anchored to the pc

  OopMap* find_map_at_offset(int pc_offset) const;

  int heap_size() const;

  void copy_to(address addr);

  // Iterates through frame for a compiled method

  static void oops_do            (const frame* fr,

                                  const RegisterMap* reg_map, OopClosure* f);

  static void update_register_map(const frame* fr, RegisterMap *reg_map);

  // Iterates through frame for a compiled method for dead ones and values, too

  static void all_do(const frame* fr, const RegisterMap* reg_map,

                     OopClosure* oop_fn,

                     void derived_oop_fn(oop* base, oop* derived),

                     OopClosure* value_fn);

  // Printing

  void print_on(outputStream* st) const;

  void print() const { print_on(tty); }

};

class OopMapStream : public StackObj {

 private:

  CompressedReadStream* _stream;

  int _mask;

  int _size;

  int _position;

  bool _valid_omv;

  OopMapValue _omv;

  void find_next();

 public:

  OopMapStream(OopMap* oop_map);

  OopMapStream(OopMap* oop_map, int oop_types_mask);

  bool is_done()                        { if(!_valid_omv) { find_next(); } return !_valid_omv; }

  void next()                           { find_next(); }

  OopMapValue current()                 { return _omv; }

};

// Derived pointer support. This table keeps track of all derived points on a

// stack.  It is cleared before each scavenge/GC.  During the traversal of all

// oops, it is filled in with references to all locations that contains a

// derived oop (assumed to be very few).  When the GC is complete, the derived

// pointers are updated based on their base pointers new value and an offset.

#ifdef COMPILER2

class DerivedPointerTable : public AllStatic {

  friend class VMStructs;

 private:

   static GrowableArray<DerivedPointerEntry*>* _list;

   static bool _active;                      // do not record pointers for verify pass etc.

 public:

  static void clear();                       // Called before scavenge/GC

  static void add(oop *derived, oop *base);  // Called during scavenge/GC

  static void update_pointers();             // Called after  scavenge/GC

  static bool is_empty()                     { return _list == NULL || _list->is_empty(); }

  static bool is_active()                    { return _active; }

  static void set_active(bool value)         { _active = value; }

};

// A utility class to temporarily "deactivate" the DerivedPointerTable.

// (Note: clients are responsible for any MT-safety issues)

class DerivedPointerTableDeactivate: public StackObj {

 private:

  bool _active;

 public:

  DerivedPointerTableDeactivate() {

    _active = DerivedPointerTable::is_active();

    if (_active) {

      DerivedPointerTable::set_active(false);

    }

  }

  ~DerivedPointerTableDeactivate() {

    assert(!DerivedPointerTable::is_active(),

           "Inconsistency: not MT-safe");

    if (_active) {

      DerivedPointerTable::set_active(true);

    }

  }

};

#endif // COMPILER2