/*

 * Copyright (c) 1998, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#ifndef SHARE_COMPILER_OOPMAP_HPP

#define SHARE_COMPILER_OOPMAP_HPP

#include "code/compressedStream.hpp"

#include "code/vmreg.hpp"

#include "memory/allocation.hpp"

#include "oops/oopsHierarchy.hpp"

// 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

//   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 OopClosure;

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

         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 };

  // Constructors

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

  // 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_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; }

  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));

  }

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

  // 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;

};

class OopMap: public ResourceObj {

  friend class OopMapStream;

  friend class VMStructs;

 private:

  int  _pc_offset; // offset in the code that this OopMap corresponds to

  int  _omv_count; // number of OopMapValues in the stream

  CompressedWriteStream* _write_stream;

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

  // Accessors

  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; }

  int count() const { return _omv_count; }

  int data_size() const  { return write_stream()->position(); }

  address data() const { return write_stream()->buffer(); }

  // 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_narrowoop(VMReg local);

  void set_callee_saved( VMReg local, VMReg caller_machine_register );

  void set_derived_oop ( VMReg local, VMReg derived_from_local_register );

  int heap_size() const;

  void copy_data_to(address addr) const;

  OopMap* deep_copy();

  bool legal_vm_reg_name(VMReg local) {

     return OopMapValue::legal_vm_reg_name(local);

  }

  // Printing

  void print_on(outputStream* st) const;

  void print() const;

  bool equals(const OopMap* other) const;

};

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;

  // Methods oops_do() and all_do() filter out NULL oops and

  // oop == CompressedOops::base() before passing oops

  // to closures.

  // 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;

};

class ImmutableOopMapBuilder;

class ImmutableOopMap {

  friend class OopMapStream;

  friend class VMStructs;

#ifdef ASSERT

  friend class ImmutableOopMapBuilder;

#endif

private:

  int _count; // contains the number of entries in this OopMap

  address data_addr() const { return (address) this + sizeof(ImmutableOopMap); }

public:

  ImmutableOopMap(const OopMap* oopmap);

  int count() const { return _count; }

#ifdef ASSERT

  int nr_of_bytes() const; // this is an expensive operation, only used in debug builds

#endif

  // Printing

  void print_on(outputStream* st) const;

  void print() const;

};

class ImmutableOopMapSet;

class ImmutableOopMap;

class OopMapSet;

class ImmutableOopMapPair {

  friend class VMStructs;

private:

  int _pc_offset; // program counter offset from the beginning of the method

  int _oopmap_offset; // offset in the data in the ImmutableOopMapSet where the ImmutableOopMap is located

public:

  ImmutableOopMapPair(int pc_offset, int oopmap_offset) : _pc_offset(pc_offset), _oopmap_offset(oopmap_offset) {

    assert(pc_offset >= 0 && oopmap_offset >= 0, "check");

  }

  const ImmutableOopMap* get_from(const ImmutableOopMapSet* set) const;

  int pc_offset() const { return _pc_offset; }

  int oopmap_offset() const { return _oopmap_offset; }

};

class ImmutableOopMapSet {

  friend class VMStructs;

private:

  int _count; // nr of ImmutableOopMapPairs in the Set

  int _size; // nr of bytes including ImmutableOopMapSet itself

  address data() const { return (address) this + sizeof(*this) + sizeof(ImmutableOopMapPair) * _count; }

public:

  ImmutableOopMapSet(const OopMapSet* oopmap_set, int size) : _count(oopmap_set->size()), _size(size) {}

  ImmutableOopMap* oopmap_at_offset(int offset) const {

    assert(offset >= 0 && offset < _size, "must be within boundaries");

    address addr = data() + offset;

    return (ImmutableOopMap*) addr;

  }

  ImmutableOopMapPair* get_pairs() const { return (ImmutableOopMapPair*) ((address) this + sizeof(*this)); }

  static ImmutableOopMapSet* build_from(const OopMapSet* oopmap_set);

  const ImmutableOopMap* find_map_at_offset(int pc_offset) const;

  const ImmutableOopMapPair* pair_at(int index) const { assert(index >= 0 && index < _count, "check"); return &get_pairs()[index]; }

  int count() const { return _count; }

  int nr_of_bytes() const { return _size; }

  void print_on(outputStream* st) const;

  void print() const;

};

class OopMapStream : public StackObj {

 private:

  CompressedReadStream* _stream;

  int _size;

  int _position;

  bool _valid_omv;

  OopMapValue _omv;

  void find_next();

 public:

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

  void next()                           { find_next(); }

  OopMapValue current()                 { return _omv; }

#ifdef ASSERT

  int stream_position() const           { return _stream->position(); }

#endif

};

class ImmutableOopMapBuilder {

private:

  class Mapping;

private:

  const OopMapSet* _set;

  const OopMap* _empty;

  const OopMap* _last;

  int _empty_offset;

  int _last_offset;

  int _offset;

  int _required;

  Mapping* _mapping;

  ImmutableOopMapSet* _new_set;

  /* Used for bookkeeping when building ImmutableOopMaps */

  class Mapping : public ResourceObj {

  public:

    enum kind_t { OOPMAP_UNKNOWN = 0, OOPMAP_NEW = 1, OOPMAP_EMPTY = 2, OOPMAP_DUPLICATE = 3 };

    kind_t _kind;

    int _offset;

    int _size;

    const OopMap* _map;

    const OopMap* _other;

    Mapping() : _kind(OOPMAP_UNKNOWN), _offset(-1), _size(-1), _map(NULL) {}

    void set(kind_t kind, int offset, int size, const OopMap* map = 0, const OopMap* other = 0) {

      _kind = kind;

      _offset = offset;

      _size = size;

      _map = map;

      _other = other;

    }

  };

public:

  ImmutableOopMapBuilder(const OopMapSet* set);

  int heap_size();

  ImmutableOopMapSet* build();

  ImmutableOopMapSet* generate_into(address buffer);

private:

  bool is_empty(const OopMap* map) const {

    return map->count() == 0;

  }

  bool is_last_duplicate(const OopMap* map) {

    if (_last != NULL && _last->count() > 0 && _last->equals(map)) {

      return true;

    }

    return false;

  }

#ifdef ASSERT

  void verify(address buffer, int size, const ImmutableOopMapSet* set);

#endif

  bool has_empty() const {

    return _empty_offset != -1;

  }

  int size_for(const OopMap* map) const;

  void fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);

  int fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);

  void fill(ImmutableOopMapSet* set, int size);

};

// 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.

#if COMPILER2_OR_JVMCI

class DerivedPointerTable : public AllStatic {

  friend class VMStructs;

 private:

  class Entry;

  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();

  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_OR_JVMCI

#endif // SHARE_COMPILER_OOPMAP_HPP