/*

 * Copyright (c) 1997, 2015, 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_VM_CODE_NMETHOD_HPP

#define SHARE_VM_CODE_NMETHOD_HPP

#include "code/codeBlob.hpp"

#include "code/pcDesc.hpp"

#include "oops/metadata.hpp"

class DirectiveSet;

// This class is used internally by nmethods, to cache

// exception/pc/handler information.

class ExceptionCache : public CHeapObj<mtCode> {

  friend class VMStructs;

 private:

  enum { cache_size = 16 };

  Klass*   _exception_type;

  address  _pc[cache_size];

  address  _handler[cache_size];

  int      _count;

  ExceptionCache* _next;

  address pc_at(int index)                     { assert(index >= 0 && index < count(),""); return _pc[index]; }

  void    set_pc_at(int index, address a)      { assert(index >= 0 && index < cache_size,""); _pc[index] = a; }

  address handler_at(int index)                { assert(index >= 0 && index < count(),""); return _handler[index]; }

  void    set_handler_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _handler[index] = a; }

  int     count()                              { return _count; }

  void    increment_count()                    { _count++; }

 public:

  ExceptionCache(Handle exception, address pc, address handler);

  Klass*    exception_type()                { return _exception_type; }

  ExceptionCache* next()                    { return _next; }

  void      set_next(ExceptionCache *ec)    { _next = ec; }

  address match(Handle exception, address pc);

  bool    match_exception_with_space(Handle exception) ;

  address test_address(address addr);

  bool    add_address_and_handler(address addr, address handler) ;

};

// cache pc descs found in earlier inquiries

class PcDescCache VALUE_OBJ_CLASS_SPEC {

  friend class VMStructs;

 private:

  enum { cache_size = 4 };

  // The array elements MUST be volatile! Several threads may modify

  // and read from the cache concurrently. find_pc_desc_internal has

  // returned wrong results. C++ compiler (namely xlC12) may duplicate

  // C++ field accesses if the elements are not volatile.

  typedef PcDesc* PcDescPtr;

  volatile PcDescPtr _pc_descs[cache_size]; // last cache_size pc_descs found

 public:

  PcDescCache() { debug_only(_pc_descs[0] = NULL); }

  void    reset_to(PcDesc* initial_pc_desc);

  PcDesc* find_pc_desc(int pc_offset, bool approximate);

  void    add_pc_desc(PcDesc* pc_desc);

  PcDesc* last_pc_desc() { return _pc_descs[0]; }

};

// nmethods (native methods) are the compiled code versions of Java methods.

//

// An nmethod contains:

//  - header                 (the nmethod structure)

//  [Relocation]

//  - relocation information

//  - constant part          (doubles, longs and floats used in nmethod)

//  - oop table

//  [Code]

//  - code body

//  - exception handler

//  - stub code

//  [Debugging information]

//  - oop array

//  - data array

//  - pcs

//  [Exception handler table]

//  - handler entry point array

//  [Implicit Null Pointer exception table]

//  - implicit null table array

class DepChange;

class Dependencies;

class ExceptionHandlerTable;

class ImplicitExceptionTable;

class AbstractCompiler;

class xmlStream;

class nmethod : public CodeBlob {

  friend class VMStructs;

  friend class JVMCIVMStructs;

  friend class NMethodSweeper;

  friend class CodeCache;  // scavengable oops

 private:

  // GC support to help figure out if an nmethod has been

  // cleaned/unloaded by the current GC.

  static unsigned char _global_unloading_clock;

  // Shared fields for all nmethod's

  Method*   _method;

  int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method

  jmethodID _jmethod_id;       // Cache of method()->jmethod_id()

#if INCLUDE_JVMCI

  // Needed to keep nmethods alive that are not the default nmethod for the associated Method.

  oop       _jvmci_installed_code;

  oop       _speculation_log;

#endif

  // To support simple linked-list chaining of nmethods:

  nmethod*  _osr_link;         // from InstanceKlass::osr_nmethods_head

  union {

    // Used by G1 to chain nmethods.

    nmethod* _unloading_next;

    // Used by non-G1 GCs to chain nmethods.

    nmethod* _scavenge_root_link; // from CodeCache::scavenge_root_nmethods

  };

  static nmethod* volatile _oops_do_mark_nmethods;

  nmethod*        volatile _oops_do_mark_link;

  AbstractCompiler* _compiler; // The compiler which compiled this nmethod

  // offsets for entry points

  address _entry_point;                      // entry point with class check

  address _verified_entry_point;             // entry point without class check

  address _osr_entry_point;                  // entry point for on stack replacement

  // Offsets for different nmethod parts

  int _exception_offset;

  // All deoptee's will resume execution at this location described by

  // this offset.

  int _deoptimize_offset;

  // All deoptee's at a MethodHandle call site will resume execution

  // at this location described by this offset.

  int _deoptimize_mh_offset;

  // Offset of the unwind handler if it exists

  int _unwind_handler_offset;

  int _consts_offset;

  int _stub_offset;

  int _oops_offset;                       // offset to where embedded oop table begins (inside data)

  int _metadata_offset;                   // embedded meta data table

  int _scopes_data_offset;

  int _scopes_pcs_offset;

  int _dependencies_offset;

  int _handler_table_offset;

  int _nul_chk_table_offset;

  int _nmethod_end_offset;

  // location in frame (offset for sp) that deopt can store the original

  // pc during a deopt.

  int _orig_pc_offset;

  int _compile_id;                           // which compilation made this nmethod

  int _comp_level;                           // compilation level

  // protected by CodeCache_lock

  bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)

  bool _marked_for_reclamation;              // Used by NMethodSweeper (set only by sweeper)

  enum MarkForDeoptimizationStatus {

    not_marked,

    deoptimize,

    deoptimize_noupdate };

  MarkForDeoptimizationStatus _mark_for_deoptimization_status; // Used for stack deoptimization

  // used by jvmti to track if an unload event has been posted for this nmethod.

  bool _unload_reported;

  // set during construction

  unsigned int _has_unsafe_access:1;         // May fault due to unsafe access.

  unsigned int _has_method_handle_invokes:1; // Has this method MethodHandle invokes?

  unsigned int _lazy_critical_native:1;      // Lazy JNI critical native

  unsigned int _has_wide_vectors:1;          // Preserve wide vectors at safepoints

  // Protected by Patching_lock

  volatile unsigned char _unloading_clock;   // Incremented after GC unloaded/cleaned the nmethod

#ifdef ASSERT

  bool _oops_are_stale;  // indicates that it's no longer safe to access oops section

#endif

  jbyte _scavenge_root_state;

#if INCLUDE_RTM_OPT

  // RTM state at compile time. Used during deoptimization to decide

  // whether to restart collecting RTM locking abort statistic again.

  RTMState _rtm_state;

#endif

  // Nmethod Flushing lock. If non-zero, then the nmethod is not removed

  // and is not made into a zombie. However, once the nmethod is made into

  // a zombie, it will be locked one final time if CompiledMethodUnload

  // event processing needs to be done.

  volatile jint _lock_count;

  // not_entrant method removal. Each mark_sweep pass will update

  // this mark to current sweep invocation count if it is seen on the

  // stack.  An not_entrant method can be removed when there are no

  // more activations, i.e., when the _stack_traversal_mark is less than

  // current sweep traversal index.

  long _stack_traversal_mark;

  // The _hotness_counter indicates the hotness of a method. The higher

  // the value the hotter the method. The hotness counter of a nmethod is

  // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method

  // is active while stack scanning (mark_active_nmethods()). The hotness

  // counter is decreased (by 1) while sweeping.

  int _hotness_counter;

  ExceptionCache *_exception_cache;

  PcDescCache     _pc_desc_cache;

  // These are used for compiled synchronized native methods to

  // locate the owner and stack slot for the BasicLock so that we can

  // properly revoke the bias of the owner if necessary. They are

  // needed because there is no debug information for compiled native

  // wrappers and the oop maps are insufficient to allow

  // frame::retrieve_receiver() to work. Currently they are expected

  // to be byte offsets from the Java stack pointer for maximum code

  // sharing between platforms. Note that currently biased locking

  // will never cause Class instances to be biased but this code

  // handles the static synchronized case as well.

  // JVMTI's GetLocalInstance() also uses these offsets to find the receiver

  // for non-static native wrapper frames.

  ByteSize _native_receiver_sp_offset;

  ByteSize _native_basic_lock_sp_offset;

  friend class nmethodLocker;

  // For native wrappers

  nmethod(Method* method,

          int nmethod_size,

          int compile_id,

          CodeOffsets* offsets,

          CodeBuffer *code_buffer,

          int frame_size,

          ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */

          ByteSize basic_lock_sp_offset,       /* synchronized natives only */

          OopMapSet* oop_maps);

  // Creation support

  nmethod(Method* method,

          int nmethod_size,

          int compile_id,

          int entry_bci,

          CodeOffsets* offsets,

          int orig_pc_offset,

          DebugInformationRecorder *recorder,

          Dependencies* dependencies,

          CodeBuffer *code_buffer,

          int frame_size,

          OopMapSet* oop_maps,

          ExceptionHandlerTable* handler_table,

          ImplicitExceptionTable* nul_chk_table,

          AbstractCompiler* compiler,

          int comp_level

#if INCLUDE_JVMCI

          , Handle installed_code,

          Handle speculation_log

#endif

          );

  // helper methods

  void* operator new(size_t size, int nmethod_size, int comp_level) throw();

  const char* reloc_string_for(u_char* begin, u_char* end);

  // Returns true if this thread changed the state of the nmethod or

  // false if another thread performed the transition.

  bool make_not_entrant_or_zombie(unsigned int state);

  void inc_decompile_count();

  // Used to manipulate the exception cache

  void add_exception_cache_entry(ExceptionCache* new_entry);

  ExceptionCache* exception_cache_entry_for_exception(Handle exception);

  // Inform external interfaces that a compiled method has been unloaded

  void post_compiled_method_unload();

  // Initailize fields to their default values

  void init_defaults();

 public:

  // create nmethod with entry_bci

  static nmethod* new_nmethod(const methodHandle& method,

                              int compile_id,

                              int entry_bci,

                              CodeOffsets* offsets,

                              int orig_pc_offset,

                              DebugInformationRecorder* recorder,

                              Dependencies* dependencies,

                              CodeBuffer *code_buffer,

                              int frame_size,

                              OopMapSet* oop_maps,

                              ExceptionHandlerTable* handler_table,

                              ImplicitExceptionTable* nul_chk_table,

                              AbstractCompiler* compiler,

                              int comp_level

#if INCLUDE_JVMCI

                              , Handle installed_code = Handle(),

                              Handle speculation_log = Handle()

#endif

                             );

  static nmethod* new_native_nmethod(const methodHandle& method,

                                     int compile_id,

                                     CodeBuffer *code_buffer,

                                     int vep_offset,

                                     int frame_complete,

                                     int frame_size,

                                     ByteSize receiver_sp_offset,

                                     ByteSize basic_lock_sp_offset,

                                     OopMapSet* oop_maps);

  // accessors

  Method* method() const                          { return _method; }

  AbstractCompiler* compiler() const              { return _compiler; }

  // type info

  bool is_nmethod() const                         { return true; }

  bool is_java_method() const                     { return !method()->is_native(); }

  bool is_native_method() const                   { return method()->is_native(); }

  bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }

  bool is_compiled_by_c1() const;

  bool is_compiled_by_jvmci() const;

  bool is_compiled_by_c2() const;

  bool is_compiled_by_shark() const;

  // boundaries for different parts

  address consts_begin          () const          { return           header_begin() + _consts_offset        ; }

  address consts_end            () const          { return           header_begin() +  code_offset()        ; }

  address insts_begin           () const          { return           header_begin() +  code_offset()        ; }

  address insts_end             () const          { return           header_begin() + _stub_offset          ; }

  address stub_begin            () const          { return           header_begin() + _stub_offset          ; }

  address stub_end              () const          { return           header_begin() + _oops_offset          ; }

  address exception_begin       () const          { return           header_begin() + _exception_offset     ; }

  address deopt_handler_begin   () const          { return           header_begin() + _deoptimize_offset    ; }

  address deopt_mh_handler_begin() const          { return           header_begin() + _deoptimize_mh_offset ; }

  address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }

  oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }

  oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }

  Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }

  Metadata** metadata_end     () const            { return (Metadata**)  (header_begin() + _scopes_data_offset)  ; }

  address scopes_data_begin     () const          { return           header_begin() + _scopes_data_offset   ; }

  address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }

  PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }

  PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }

  address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }

  address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }

  address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }

  address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }

  address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }

  address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }

  // Sizes

  int consts_size       () const                  { return            consts_end       () -            consts_begin       (); }

  int insts_size        () const                  { return            insts_end        () -            insts_begin        (); }

  int stub_size         () const                  { return            stub_end         () -            stub_begin         (); }

  int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }

  int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }

  int scopes_data_size  () const                  { return            scopes_data_end  () -            scopes_data_begin  (); }

  int scopes_pcs_size   () const                  { return (intptr_t) scopes_pcs_end   () - (intptr_t) scopes_pcs_begin   (); }

  int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }

  int handler_table_size() const                  { return            handler_table_end() -            handler_table_begin(); }

  int nul_chk_table_size() const                  { return            nul_chk_table_end() -            nul_chk_table_begin(); }

  int     oops_count() const { assert(oops_size() % oopSize == 0, "");  return (oops_size() / oopSize) + 1; }

  int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }

  int total_size        () const;

  void dec_hotness_counter()        { _hotness_counter--; }

  void set_hotness_counter(int val) { _hotness_counter = val; }

  int  hotness_counter() const      { return _hotness_counter; }

  // Containment

  bool consts_contains       (address addr) const { return consts_begin       () <= addr && addr < consts_end       (); }

  bool insts_contains        (address addr) const { return insts_begin        () <= addr && addr < insts_end        (); }

  bool stub_contains         (address addr) const { return stub_begin         () <= addr && addr < stub_end         (); }

  bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }

  bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }

  bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }

  bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }

  bool handler_table_contains(address addr) const { return handler_table_begin() <= addr && addr < handler_table_end(); }

  bool nul_chk_table_contains(address addr) const { return nul_chk_table_begin() <= addr && addr < nul_chk_table_end(); }

  // entry points

  address entry_point() const                     { return _entry_point;             } // normal entry point

  address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct

  enum { in_use       = 0,   // executable nmethod

         not_entrant  = 1,   // marked for deoptimization but activations may still exist,

                             // will be transformed to zombie when all activations are gone

         zombie       = 2,   // no activations exist, nmethod is ready for purge

         unloaded     = 3 }; // there should be no activations, should not be called,

                             // will be transformed to zombie immediately

  // flag accessing and manipulation

  bool  is_in_use() const                         { return _state == in_use; }

  bool  is_alive() const                          { return _state == in_use || _state == not_entrant; }

  bool  is_not_entrant() const                    { return _state == not_entrant; }

  bool  is_zombie() const                         { return _state == zombie; }

#if INCLUDE_RTM_OPT

  // rtm state accessing and manipulating

  RTMState  rtm_state() const                     { return _rtm_state; }

  void set_rtm_state(RTMState state)              { _rtm_state = state; }

#endif

  // Make the nmethod non entrant. The nmethod will continue to be

  // alive.  It is used when an uncommon trap happens.  Returns true

  // if this thread changed the state of the nmethod or false if

  // another thread performed the transition.

  bool  make_not_entrant() {

    assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");

    return make_not_entrant_or_zombie(not_entrant);

  }

  bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }

  // used by jvmti to track if the unload event has been reported

  bool  unload_reported()                         { return _unload_reported; }

  void  set_unload_reported()                     { _unload_reported = true; }

  void set_unloading_next(nmethod* next)          { _unloading_next = next; }

  nmethod* unloading_next()                       { return _unloading_next; }

  static unsigned char global_unloading_clock()   { return _global_unloading_clock; }

  static void increase_unloading_clock();

  void set_unloading_clock(unsigned char unloading_clock);

  unsigned char unloading_clock();

  bool  is_marked_for_deoptimization() const      { return _mark_for_deoptimization_status != not_marked; }

  void  mark_for_deoptimization(bool inc_recompile_counts = true) {

    _mark_for_deoptimization_status = (inc_recompile_counts ? deoptimize : deoptimize_noupdate);

  }

  bool update_recompile_counts() const {

    // Update recompile counts when either the update is explicitly requested (deoptimize)

    // or the nmethod is not marked for deoptimization at all (not_marked).

    // The latter happens during uncommon traps when deoptimized nmethod is made not entrant.

    return _mark_for_deoptimization_status != deoptimize_noupdate;

  }

  void  make_unloaded(BoolObjectClosure* is_alive, oop cause);

  bool has_dependencies()                         { return dependencies_size() != 0; }

  void flush_dependencies(BoolObjectClosure* is_alive);

  bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }

  void set_has_flushed_dependencies()             {