/*

 * Copyright (c) 1997, 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_OOPS_GENERATEOOPMAP_HPP

#define SHARE_OOPS_GENERATEOOPMAP_HPP

#include "interpreter/bytecodeStream.hpp"

#include "memory/allocation.hpp"

#include "oops/method.hpp"

#include "oops/oopsHierarchy.hpp"

#include "runtime/signature.hpp"

#include "utilities/bitMap.hpp"

// Forward definition

class GenerateOopMap;

class BasicBlock;

class CellTypeState;

class StackMap;

// These two should be removed. But requires som code to be cleaned up

#define MAXARGSIZE      256      // This should be enough

#define MAX_LOCAL_VARS  65536    // 16-bit entry

typedef void (*jmpFct_t)(GenerateOopMap *c, int bcpDelta, int* data);

//  RetTable

//

// Contains maping between jsr targets and there return addresses. One-to-many mapping

//

class RetTableEntry : public ResourceObj {

 private:

  static int _init_nof_jsrs;                      // Default size of jsrs list

  int _target_bci;                                // Target PC address of jump (bytecode index)

  GrowableArray<intptr_t> * _jsrs;                     // List of return addresses  (bytecode index)

  RetTableEntry *_next;                           // Link to next entry

 public:

   RetTableEntry(int target, RetTableEntry *next);

  // Query

  int target_bci() const                      { return _target_bci; }

  int nof_jsrs() const                        { return _jsrs->length(); }

  int jsrs(int i) const                       { assert(i>=0 && i<nof_jsrs(), "Index out of bounds"); return _jsrs->at(i); }

  // Update entry

  void add_jsr    (int return_bci)            { _jsrs->append(return_bci); }

  void add_delta  (int bci, int delta);

  RetTableEntry * next()  const               { return _next; }

};

class RetTable {

 private:

  RetTableEntry *_first;

  static int _init_nof_entries;

  void add_jsr(int return_bci, int target_bci);   // Adds entry to list

 public:

  RetTable()                                                  { _first = NULL; }

  void compute_ret_table(const methodHandle& method);

  void update_ret_table(int bci, int delta);

  RetTableEntry* find_jsrs_for_target(int targBci);

};

//

// CellTypeState

//

class CellTypeState {

 private:

  unsigned int _state;

  // Masks for separating the BITS and INFO portions of a CellTypeState

  enum { info_mask            = right_n_bits(28),

         bits_mask            = (int)(~info_mask) };

  // These constant are used for manipulating the BITS portion of a

  // CellTypeState

  enum { uninit_bit           = (int)(nth_bit(31)),

         ref_bit              = nth_bit(30),

         val_bit              = nth_bit(29),

         addr_bit             = nth_bit(28),

         live_bits_mask       = (int)(bits_mask & ~uninit_bit) };

  // These constants are used for manipulating the INFO portion of a

  // CellTypeState

  enum { top_info_bit         = nth_bit(27),

         not_bottom_info_bit  = nth_bit(26),

         info_data_mask       = right_n_bits(26),

         info_conflict        = info_mask };

  // Within the INFO data, these values are used to distinguish different

  // kinds of references.

  enum { ref_not_lock_bit     = nth_bit(25),  // 0 if this reference is locked as a monitor

         ref_slot_bit         = nth_bit(24),  // 1 if this reference is a "slot" reference,

                                              // 0 if it is a "line" reference.

         ref_data_mask        = right_n_bits(24) };

  // These values are used to initialize commonly used CellTypeState

  // constants.

  enum { bottom_value         = 0,

         uninit_value         = (int)(uninit_bit | info_conflict),

         ref_value            = ref_bit,

         ref_conflict         = ref_bit | info_conflict,

         val_value            = val_bit | info_conflict,

         addr_value           = addr_bit,

         addr_conflict        = addr_bit | info_conflict };

 public:

  // Since some C++ constructors generate poor code for declarations of the

  // form...

  //

  //   CellTypeState vector[length];

  //

  // ...we avoid making a constructor for this class.  CellTypeState values

  // should be constructed using one of the make_* methods:

  static CellTypeState make_any(int state) {

    CellTypeState s;

    s._state = state;

    // Causes SS10 warning.

    // assert(s.is_valid_state(), "check to see if CellTypeState is valid");

    return s;

  }

  static CellTypeState make_bottom() {

    return make_any(0);

  }

  static CellTypeState make_top() {

    return make_any(AllBits);

  }

  static CellTypeState make_addr(int bci) {

    assert((bci >= 0) && (bci < info_data_mask), "check to see if ret addr is valid");

    return make_any(addr_bit | not_bottom_info_bit | (bci & info_data_mask));

  }

  static CellTypeState make_slot_ref(int slot_num) {

    assert(slot_num >= 0 && slot_num < ref_data_mask, "slot out of range");

    return make_any(ref_bit | not_bottom_info_bit | ref_not_lock_bit | ref_slot_bit |

                    (slot_num & ref_data_mask));

  }

  static CellTypeState make_line_ref(int bci) {

    assert(bci >= 0 && bci < ref_data_mask, "line out of range");

    return make_any(ref_bit | not_bottom_info_bit | ref_not_lock_bit |

                    (bci & ref_data_mask));

  }

  static CellTypeState make_lock_ref(int bci) {

    assert(bci >= 0 && bci < ref_data_mask, "line out of range");

    return make_any(ref_bit | not_bottom_info_bit | (bci & ref_data_mask));

  }

  // Query methods:

  bool is_bottom() const                { return _state == 0; }

  bool is_live() const                  { return ((_state & live_bits_mask) != 0); }

  bool is_valid_state() const {

    // Uninitialized and value cells must contain no data in their info field:

    if ((can_be_uninit() || can_be_value()) && !is_info_top()) {

      return false;

    }

    // The top bit is only set when all info bits are set:

    if (is_info_top() && ((_state & info_mask) != info_mask)) {

      return false;

    }

    // The not_bottom_bit must be set when any other info bit is set:

    if (is_info_bottom() && ((_state & info_mask) != 0)) {

      return false;

    }

    return true;

  }

  bool is_address() const               { return ((_state & bits_mask) == addr_bit); }

  bool is_reference() const             { return ((_state & bits_mask) == ref_bit); }

  bool is_value() const                 { return ((_state & bits_mask) == val_bit); }

  bool is_uninit() const                { return ((_state & bits_mask) == (uint)uninit_bit); }

  bool can_be_address() const           { return ((_state & addr_bit) != 0); }

  bool can_be_reference() const         { return ((_state & ref_bit) != 0); }

  bool can_be_value() const             { return ((_state & val_bit) != 0); }

  bool can_be_uninit() const            { return ((_state & uninit_bit) != 0); }

  bool is_info_bottom() const           { return ((_state & not_bottom_info_bit) == 0); }

  bool is_info_top() const              { return ((_state & top_info_bit) != 0); }

  int  get_info() const {

    assert((!is_info_top() && !is_info_bottom()),

           "check to make sure top/bottom info is not used");

    return (_state & info_data_mask);

  }

  bool is_good_address() const          { return is_address() && !is_info_top(); }

  bool is_lock_reference() const {

    return ((_state & (bits_mask | top_info_bit | ref_not_lock_bit)) == ref_bit);

  }

  bool is_nonlock_reference() const {

    return ((_state & (bits_mask | top_info_bit | ref_not_lock_bit)) == (ref_bit | ref_not_lock_bit));

  }

  bool equal(CellTypeState a) const     { return _state == a._state; }

  bool equal_kind(CellTypeState a) const {

    return (_state & bits_mask) == (a._state & bits_mask);

  }

  char to_char() const;

  // Merge

  CellTypeState merge (CellTypeState cts, int slot) const;

  // Debugging output

  void print(outputStream *os);

  // Default values of common values

  static CellTypeState bottom;

  static CellTypeState uninit;

  static CellTypeState ref;

  static CellTypeState value;

  static CellTypeState refUninit;

  static CellTypeState varUninit;

  static CellTypeState top;

  static CellTypeState addr;

};

//

// BasicBlockStruct

//

class BasicBlock: ResourceObj {

 private:

  bool            _changed;                 // Reached a fixpoint or not

 public:

  enum Constants {

    _dead_basic_block = -2,

    _unreached        = -1                  // Alive but not yet reached by analysis

    // >=0                                  // Alive and has a merged state

  };

  int             _bci;                     // Start of basic block

  int             _end_bci;                 // Bci of last instruction in basicblock

  int             _max_locals;              // Determines split between vars and stack

  int             _max_stack;               // Determines split between stack and monitors

  CellTypeState*  _state;                   // State (vars, stack) at entry.

  int             _stack_top;               // -1 indicates bottom stack value.

  int             _monitor_top;             // -1 indicates bottom monitor stack value.

  CellTypeState* vars()                     { return _state; }

  CellTypeState* stack()                    { return _state + _max_locals; }

  bool changed()                            { return _changed; }

  void set_changed(bool s)                  { _changed = s; }

  bool is_reachable() const                 { return _stack_top >= 0; }  // Analysis has reached this basicblock

  // All basicblocks that are unreachable are going to have a _stack_top == _dead_basic_block.

  // This info. is setup in a pre-parse before the real abstract interpretation starts.

  bool is_dead() const                      { return _stack_top == _dead_basic_block; }

  bool is_alive() const                     { return _stack_top != _dead_basic_block; }

  void mark_as_alive()                      { assert(is_dead(), "must be dead"); _stack_top = _unreached; }

};

//

//  GenerateOopMap

//

// Main class used to compute the pointer-maps in a Method

//

class GenerateOopMap {

 protected:

  // _monitor_top is set to this constant to indicate that a monitor matching

  // problem was encountered prior to this point in control flow.

  enum { bad_monitors = -1 };

  // Main variables

  methodHandle _method;                     // The method we are examine

  RetTable     _rt;                         // Contains the return address mappings

  int          _max_locals;                 // Cached value of no. of locals

  int          _max_stack;                  // Cached value of max. stack depth

  int          _max_monitors;               // Cached value of max. monitor stack depth

  int          _has_exceptions;             // True, if exceptions exist for method

  bool         _got_error;                  // True, if an error occurred during interpretation.

  Handle       _exception;                  // Exception if got_error is true.

  bool         _did_rewriting;              // was bytecodes rewritten

  bool         _did_relocation;             // was relocation neccessary

  bool         _monitor_safe;               // The monitors in this method have been determined

                                            // to be safe.

  // Working Cell type state

  int            _state_len;                // Size of states

  CellTypeState *_state;                    // list of states

  char          *_state_vec_buf;            // Buffer used to print a readable version of a state

  int            _stack_top;

  int            _monitor_top;

  // Timing and statistics

  static elapsedTimer _total_oopmap_time;   // Holds cumulative oopmap generation time

  static long         _total_byte_count;    // Holds cumulative number of bytes inspected

  // Cell type methods

  void            init_state();

  void            make_context_uninitialized ();

  int             methodsig_to_effect        (Symbol* signature, bool isStatic, CellTypeState* effect);

  bool            merge_local_state_vectors  (CellTypeState* cts, CellTypeState* bbts);

  bool            merge_monitor_state_vectors(CellTypeState* cts, CellTypeState* bbts);

  void            copy_state                 (CellTypeState *dst, CellTypeState *src);

  void            merge_state_into_bb        (BasicBlock *bb);

  static void     merge_state                (GenerateOopMap *gom, int bcidelta, int* data);

  void            set_var                    (int localNo, CellTypeState cts);

  CellTypeState   get_var                    (int localNo);

  CellTypeState   pop                        ();

  void            push                       (CellTypeState cts);

  CellTypeState   monitor_pop                ();

  void            monitor_push               (CellTypeState cts);

  CellTypeState * vars                       ()                                             { return _state; }

  CellTypeState * stack                      ()                                             { return _state+_max_locals; }

  CellTypeState * monitors                   ()                                             { return _state+_max_locals+_max_stack; }

  void            replace_all_CTS_matches    (CellTypeState match,

                                              CellTypeState replace);

  void            print_states               (outputStream *os, CellTypeState *vector, int num);

  void            print_current_state        (outputStream   *os,

                                              BytecodeStream *itr,

                                              bool            detailed);

  void            report_monitor_mismatch    (const char *msg);

  // Basicblock info

  BasicBlock *    _basic_blocks;             // Array of basicblock info

  int             _gc_points;

  int             _bb_count;

  ResourceBitMap  _bb_hdr_bits;

  // Basicblocks methods

  void          initialize_bb               ();

  void          mark_bbheaders_and_count_gc_points();

  bool          is_bb_header                (int bci) const   {

    return _bb_hdr_bits.at(bci);

  }

  int           gc_points                   () const                          { return _gc_points; }

  int           bb_count                    () const                          { return _bb_count; }

  void          set_bbmark_bit              (int bci);

  BasicBlock *  get_basic_block_at          (int bci) const;

  BasicBlock *  get_basic_block_containing  (int bci) const;

  void          interp_bb                   (BasicBlock *bb);

  void          restore_state               (BasicBlock *bb);

  int           next_bb_start_pc            (BasicBlock *bb);

  void          update_basic_blocks         (int bci, int delta, int new_method_size);

  static void   bb_mark_fct                 (GenerateOopMap *c, int deltaBci, int *data);

  // Dead code detection

  void          mark_reachable_code();

  static void   reachable_basicblock        (GenerateOopMap *c, int deltaBci, int *data);

  // Interpretation methods (primary)

  void  do_interpretation                   ();

  void  init_basic_blocks                   ();

  void  setup_method_entry_state            ();

  void  interp_all                          ();

  // Interpretation methods (secondary)

  void  interp1                             (BytecodeStream *itr);

  void  do_exception_edge                   (BytecodeStream *itr);

  void  check_type                          (CellTypeState expected, CellTypeState actual);

  void  ppstore                             (CellTypeState *in,  int loc_no);

  void  ppload                              (CellTypeState *out, int loc_no);

  void  ppush1                              (CellTypeState in);

  void  ppush                               (CellTypeState *in);

  void  ppop1                               (CellTypeState out);

  void  ppop                                (CellTypeState *out);

  void  ppop_any                            (int poplen);

  void  pp                                  (CellTypeState *in, CellTypeState *out);

  void  pp_new_ref                          (CellTypeState *in, int bci);

  void  ppdupswap                           (int poplen, const char *out);

  void  do_ldc                              (int bci);

  void  do_astore                           (int idx);

  void  do_jsr                              (int delta);

  void  do_field                            (int is_get, int is_static, int idx, int bci);

  void  do_method                           (int is_static, int is_interface, int idx, int bci);

  void  do_multianewarray                   (int dims, int bci);

  void  do_monitorenter                     (int bci);

  void  do_monitorexit                      (int bci);

  void  do_return_monitor_check             ();

  void  do_checkcast                        ();

  CellTypeState *sigchar_to_effect          (char sigch, int bci, CellTypeState *out);

  int copy_cts                              (CellTypeState *dst, CellTypeState *src);

  // Error handling

  void  error_work                          (const char *format, va_list ap) ATTRIBUTE_PRINTF(2, 0);

  void  report_error                        (const char *format, ...) ATTRIBUTE_PRINTF(2, 3);

  void  verify_error                        (const char *format, ...) ATTRIBUTE_PRINTF(2, 3);

  bool  got_error()                         { return _got_error; }

  // Create result set

  bool  _report_result;

  bool  _report_result_for_send;            // Unfortunatly, stackmaps for sends are special, so we need some extra

  BytecodeStream *_itr_send;                // variables to handle them properly.

  void  report_result                       ();

  // Initvars

  GrowableArray<intptr_t> * _init_vars;

  void  initialize_vars                     ();

  void  add_to_ref_init_set                 (int localNo);

  // Conflicts rewrite logic

  bool      _conflict;                      // True, if a conflict occurred during interpretation

  int       _nof_refval_conflicts;          // No. of conflicts that require rewrites

  int *     _new_var_map;

  void record_refval_conflict               (int varNo);

  void rewrite_refval_conflicts             ();

  void rewrite_refval_conflict              (int from, int to);

  bool rewrite_refval_conflict_inst         (BytecodeStream *i, int from, int to);

  bool rewrite_load_or_store                (BytecodeStream *i, Bytecodes::Code bc, Bytecodes::Code bc0, unsigned int varNo);

  void expand_current_instr                 (int bci, int ilen, int newIlen, u_char inst_buffer[]);

  bool is_astore                            (BytecodeStream *itr, int *index);

  bool is_aload                             (BytecodeStream *itr, int *index);

  // List of bci's where a return address is on top of the stack

  GrowableArray<intptr_t> *_ret_adr_tos;

  bool stack_top_holds_ret_addr             (int bci);

  void compute_ret_adr_at_TOS               ();

  void update_ret_adr_at_TOS                (int bci, int delta);

  int  binsToHold                           (int no)                      { return  ((no+(BitsPerWord-1))/BitsPerWord); }

  char *state_vec_to_string                 (CellTypeState* vec, int len);

  // Helper method. Can be used in subclasses to fx. calculate gc_points. If the current instuction

  // is a control transfer, then calls the jmpFct all possible destinations.

  void  ret_jump_targets_do                 (BytecodeStream *bcs, jmpFct_t jmpFct, int varNo,int *data);

  bool  jump_targets_do                     (BytecodeStream *bcs, jmpFct_t jmpFct, int *data);

  friend class RelocCallback;

 public:

  GenerateOopMap(const methodHandle& method);

  // Compute the map.

  void compute_map(TRAPS);

  void result_for_basicblock(int bci);    // Do a callback on fill_stackmap_for_opcodes for basicblock containing bci

  // Query

  int max_locals() const                           { return _max_locals; }

  Method* method() const                           { return _method(); }

  methodHandle method_as_handle() const            { return _method; }

  bool did_rewriting()                             { return _did_rewriting; }

  bool did_relocation()                            { return _did_relocation; }

  static void print_time();

  // Monitor query

  bool monitor_safe()                              { return _monitor_safe; }

  // Specialization methods. Intended use:

  // - possible_gc_point must return true for every bci for which the stackmaps must be returned

  // - fill_stackmap_prolog is called just before the result is reported. The arguments tells the estimated

  //   number of gc points

  // - fill_stackmap_for_opcodes is called once for each bytecode index in order (0...code_length-1)

  // - fill_stackmap_epilog is called after all results has been reported. Note: Since the algorithm does not report

  //   stackmaps for deadcode, fewer gc_points might have been encounted than assumed during the epilog. It is the

  //   responsibility of the subclass to count the correct number.

  // - fill_init_vars are called once with the result of the init_vars computation

  //

  // All these methods are used during a call to: compute_map. Note: Non of the return results are valid

  // after compute_map returns, since all values are allocated as resource objects.

  //

  // All virtual method must be implemented in subclasses

  virtual bool allow_rewrites             () const                        { return false; }

  virtual bool report_results             () const                        { return true;  }

  virtual bool report_init_vars           () const                        { return true;  }

  virtual bool possible_gc_point          (BytecodeStream *bcs)           { ShouldNotReachHere(); return false; }

  virtual void fill_stackmap_prolog       (int nof_gc_points)             { ShouldNotReachHere(); }

  virtual void fill_stackmap_epilog       ()                              { ShouldNotReachHere(); }

  virtual void fill_stackmap_for_opcodes  (BytecodeStream *bcs,

                                           CellTypeState* vars,

                                           CellTypeState* stack,

                                           int stackTop)                  { ShouldNotReachHere(); }

  virtual void fill_init_vars             (GrowableArray<intptr_t> *init_vars) { ShouldNotReachHere();; }

};

//

// Subclass of the GenerateOopMap Class that just do rewrites of the method, if needed.

// It does not store any oopmaps.

//

class ResolveOopMapConflicts: public GenerateOopMap {

 private:

  bool _must_clear_locals;

  virtual bool report_results() const     { return false; }

  virtual bool report_init_vars() const   { return true;  }

  virtual bool allow_rewrites() const     { return true;  }

  virtual bool possible_gc_point          (BytecodeStream *bcs)           { return false; }

  virtual void fill_stackmap_prolog       (int nof_gc_points)             {}

  virtual void fill_stackmap_epilog       ()                              {}

  virtual void fill_stackmap_for_opcodes  (BytecodeStream *bcs,

                                           CellTypeState* vars,

                                           CellTypeState* stack,

                                           int stack_top)                 {}