/*

 * Copyright 1997-2009 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.

 *

 */

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

// exception/pc/handler information.

class ExceptionCache : public CHeapObj {

  friend class VMStructs;

 private:

  static address _unwind_handler;

  enum { cache_size = 16 };

  klassOop _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);

  klassOop  exception_type()                { return _exception_type; }

  klassOop* exception_type_addr()           { 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) ;

  static address unwind_handler() { return _unwind_handler; }

};

// cache pc descs found in earlier inquiries

class PcDescCache VALUE_OBJ_CLASS_SPEC {

  friend class VMStructs;

 private:

  enum { cache_size = 4 };

  PcDesc* _last_pc_desc;         // most recent pc_desc found

  PcDesc* _pc_descs[cache_size]; // last cache_size pc_descs found

 public:

  PcDescCache() { debug_only(_last_pc_desc = 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 _last_pc_desc; }

};

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

struct nmFlags {

  friend class VMStructs;

  unsigned int version:8;                 // version number (0 = first version)

  unsigned int level:4;                   // optimization level

  unsigned int age:4;                     // age (in # of sweep steps)

  unsigned int state:2;                   // {alive, zombie, unloaded)

  unsigned int isUncommonRecompiled:1;    // recompiled because of uncommon trap?

  unsigned int isToBeRecompiled:1;        // to be recompiled as soon as it matures

  unsigned int hasFlushedDependencies:1;  // Used for maintenance of dependencies

  unsigned int markedForReclamation:1;    // Used by NMethodSweeper

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

  void clear();

};

// A nmethod contains:

//  - header                 (the nmethod structure)

//  [Relocation]

//  - relocation information

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

//  [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 Dependencies;

class ExceptionHandlerTable;

class ImplicitExceptionTable;

class AbstractCompiler;

class xmlStream;

class nmethod : public CodeBlob {

  friend class VMStructs;

  friend class NMethodSweeper;

  friend class CodeCache;  // non-perm oops

 private:

  // Shared fields for all nmethod's

  static int _zombie_instruction_size;

  methodOop _method;

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

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

  nmethod*  _osr_link;         // from instanceKlass::osr_nmethods_head

  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 different nmethod parts

  int _exception_offset;

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

  int _deoptimize_offset;

#ifdef HAVE_DTRACE_H

  int _trap_offset;

#endif // def HAVE_DTRACE_H

  int _stub_offset;

  int _consts_offset;

  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

  // 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

  nmFlags flags;           // various flags to keep track of nmethod state

  bool _markedForDeoptimization;       // Used for stack deoptimization

  enum { alive        = 0,

         not_entrant  = 1, // uncommon trap has happened but activations may still exist

         zombie       = 2,

         unloaded     = 3 };

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

  bool _unload_reported;

  jbyte _scavenge_root_state;

  NOT_PRODUCT(bool _has_debug_info; )

  // Nmethod Flushing lock (if non-zero, then the nmethod is not removed)

  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 is no

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

  // current sweep traversal index.

  long _stack_traversal_mark;

  ExceptionCache *_exception_cache;

  PcDescCache     _pc_desc_cache;

  // These are only 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.

  ByteSize _compiled_synchronized_native_basic_lock_owner_sp_offset;

  ByteSize _compiled_synchronized_native_basic_lock_sp_offset;

  friend class nmethodLocker;

  // For native wrappers

  nmethod(methodOop method,

          int nmethod_size,

          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);

#ifdef HAVE_DTRACE_H

  // For native wrappers

  nmethod(methodOop method,

          int nmethod_size,

          CodeOffsets* offsets,

          CodeBuffer *code_buffer,

          int frame_size);

#endif // def HAVE_DTRACE_H

  // Creation support

  nmethod(methodOop 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);

  // helper methods

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

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

  void make_not_entrant_or_zombie(int state);

  void inc_decompile_count();

  // used to check that writes to nmFlags are done consistently.

  static void check_safepoint() PRODUCT_RETURN;

  // 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

  inline void post_compiled_method_unload();

 public:

  // create nmethod with entry_bci

  static nmethod* new_nmethod(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);

  static nmethod* new_native_nmethod(methodHandle method,

                                     CodeBuffer *code_buffer,

                                     int vep_offset,

                                     int frame_complete,

                                     int frame_size,

                                     ByteSize receiver_sp_offset,

                                     ByteSize basic_lock_sp_offset,

                                     OopMapSet* oop_maps);

#ifdef HAVE_DTRACE_H

  // The method we generate for a dtrace probe has to look

  // like an nmethod as far as the rest of the system is concerned

  // which is somewhat unfortunate.

  static nmethod* new_dtrace_nmethod(methodHandle method,

                                     CodeBuffer *code_buffer,

                                     int vep_offset,

                                     int trap_offset,

                                     int frame_complete,

                                     int frame_size);

  int trap_offset() const      { return _trap_offset; }

  address trap_address() const { return code_begin() + _trap_offset; }

#endif // def HAVE_DTRACE_H

  // accessors

  methodOop method() const                        { return _method; }

  AbstractCompiler* compiler() const              { return _compiler; }

#ifndef PRODUCT

  bool has_debug_info() const                     { return _has_debug_info; }

  void set_has_debug_info(bool f)                 { _has_debug_info = false; }

#endif // NOT PRODUCT

  // 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_c2() const;

  // boundaries for different parts

  address code_begin         () const             { return _entry_point; }

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

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

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

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

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

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

  address consts_end         () const             { return           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   ; }

  int code_size         () const                  { return      code_end         () -      code_begin         (); }

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

  int consts_size       () const                  { return      consts_end       () -      consts_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 total_size        () const;

  bool code_contains         (address addr) const { return code_begin         () <= addr && addr < code_end         (); }

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

  bool consts_contains       (address addr) const { return consts_begin       () <= addr && addr < consts_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

  // flag accessing and manipulation

  bool  is_in_use() const                         { return flags.state == alive; }

  bool  is_alive() const                          { return flags.state == alive || flags.state == not_entrant; }

  bool  is_not_entrant() const                    { return flags.state == not_entrant; }

  bool  is_zombie() const                         { return flags.state == zombie; }

  bool  is_unloaded() const                       { return flags.state == unloaded;   }

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

  // It is used when an uncommon trap happens.

  void  make_not_entrant()                        { make_not_entrant_or_zombie(not_entrant); }

  void  make_zombie()                             { 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; }

  bool  is_marked_for_deoptimization() const      { return _markedForDeoptimization; }

  void  mark_for_deoptimization()                 { _markedForDeoptimization = true; }

  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 flags.hasFlushedDependencies; }

  void  set_has_flushed_dependencies()            {

    check_safepoint();

    assert(!has_flushed_dependencies(), "should only happen once");

    flags.hasFlushedDependencies = 1;

  }

  bool  is_marked_for_reclamation() const         { return flags.markedForReclamation; }

  void  mark_for_reclamation()                    { check_safepoint(); flags.markedForReclamation = 1; }

  void  unmark_for_reclamation()                  { check_safepoint(); flags.markedForReclamation = 0; }

  bool  has_unsafe_access() const                 { return flags.has_unsafe_access; }

  void  set_has_unsafe_access(bool z)             { flags.has_unsafe_access = z; }

  int   level() const                             { return flags.level; }

  void  set_level(int newLevel)                   { check_safepoint(); flags.level = newLevel; }

  int   comp_level() const                        { return _comp_level; }

  int   version() const                           { return flags.version; }

  void  set_version(int v);

  // Non-perm oop support

  bool  on_scavenge_root_list() const                  { return (_scavenge_root_state & 1) != 0; }

 protected:

  enum { npl_on_list = 0x01, npl_marked = 0x10 };

  void  set_on_scavenge_root_list()                    { _scavenge_root_state = npl_on_list; }

  void  clear_on_scavenge_root_list()                  { _scavenge_root_state = 0; }

  // assertion-checking and pruning logic uses the bits of _scavenge_root_state

#ifndef PRODUCT

  void  set_scavenge_root_marked()                     { _scavenge_root_state |= npl_marked; }

  void  clear_scavenge_root_marked()                   { _scavenge_root_state &= ~npl_marked; }

  bool  scavenge_root_not_marked()                     { return (_scavenge_root_state &~ npl_on_list) == 0; }

  // N.B. there is no positive marked query, and we only use the not_marked query for asserts.

#endif //PRODUCT

  nmethod* scavenge_root_link() const                  { return _scavenge_root_link; }

  void     set_scavenge_root_link(nmethod *n)          { _scavenge_root_link = n; }

 public:

  // Sweeper support

  long  stack_traversal_mark()                    { return _stack_traversal_mark; }

  void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }

  // Exception cache support

  ExceptionCache* exception_cache() const         { return _exception_cache; }

  void set_exception_cache(ExceptionCache *ec)    { _exception_cache = ec; }

  address handler_for_exception_and_pc(Handle exception, address pc);

  void add_handler_for_exception_and_pc(Handle exception, address pc, address handler);

  void remove_from_exception_cache(ExceptionCache* ec);

  // implicit exceptions support

  address continuation_for_implicit_exception(address pc);

  // On-stack replacement support

  int   osr_entry_bci() const                     { assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod"); return _entry_bci; }

  address  osr_entry() const                      { assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod"); return _osr_entry_point; }

  void  invalidate_osr_method();

  nmethod* osr_link() const                       { return _osr_link; }

  void     set_osr_link(nmethod *n)               { _osr_link = n; }

  // tells whether frames described by this nmethod can be deoptimized

  // note: native wrappers cannot be deoptimized.

  bool can_be_deoptimized() const { return is_java_method(); }

  // Inline cache support

  void clear_inline_caches();

  void cleanup_inline_caches();

  bool inlinecache_check_contains(address addr) const {

    return (addr >= instructions_begin() && addr < verified_entry_point());

  }

  // unlink and deallocate this nmethod

  // Only NMethodSweeper class is expected to use this. NMethodSweeper is not

  // expected to use any other private methods/data in this class.

 protected:

  void flush();

 public:

  // If returning true, it is unsafe to remove this nmethod even though it is a zombie

  // nmethod, since the VM might have a reference to it. Should only be called from a  safepoint.

  bool is_locked_by_vm() const                    { return _lock_count >0; }

  // See comment at definition of _last_seen_on_stack

  void mark_as_seen_on_stack();

  bool can_not_entrant_be_converted();

  // Evolution support. We make old (discarded) compiled methods point to new methodOops.

  void set_method(methodOop method) { _method = method; }

  // GC support

  void do_unloading(BoolObjectClosure* is_alive, OopClosure* keep_alive,

                    bool unloading_occurred);

  bool can_unload(BoolObjectClosure* is_alive, OopClosure* keep_alive,

                  oop* root, bool unloading_occurred);

  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map,

                                     OopClosure* f);

  virtual void oops_do(OopClosure* f) { oops_do(f, false); }

  void         oops_do(OopClosure* f, bool do_strong_roots_only);

  bool detect_scavenge_root_oops();

  void verify_scavenge_root_oops() PRODUCT_RETURN;

  bool test_set_oops_do_mark();

  static void oops_do_marking_prologue();

  static void oops_do_marking_epilogue();

  static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }

  DEBUG_ONLY(bool test_oops_do_mark() { return _oops_do_mark_link != NULL; })

  // ScopeDesc for an instruction

  ScopeDesc* scope_desc_at(address pc);

 private:

  ScopeDesc* scope_desc_in(address begin, address end);

  address* orig_pc_addr(const frame* fr ) { return (address*) ((address)fr->unextended_sp() + _orig_pc_offset); }

  PcDesc* find_pc_desc_internal(address pc, bool approximate);

  PcDesc* find_pc_desc(address pc, bool approximate) {

    PcDesc* desc = _pc_desc_cache.last_pc_desc();

    if (desc != NULL && desc->pc_offset() == pc - instructions_begin()) {

      return desc;

    }

    return find_pc_desc_internal(pc, approximate);

  }

 public: