1 /*
   2  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CODE_NMETHOD_HPP
  26 #define SHARE_VM_CODE_NMETHOD_HPP
  27 
  28 #include "code/compiledMethod.hpp"
  29 
  30 class DepChange;
  31 class DirectiveSet;
  32 
  33 // nmethods (native methods) are the compiled code versions of Java methods.
  34 //
  35 // An nmethod contains:
  36 //  - header                 (the nmethod structure)
  37 //  [Relocation]
  38 //  - relocation information
  39 //  - constant part          (doubles, longs and floats used in nmethod)
  40 //  - oop table
  41 //  [Code]
  42 //  - code body
  43 //  - exception handler
  44 //  - stub code
  45 //  [Debugging information]
  46 //  - oop array
  47 //  - data array
  48 //  - pcs
  49 //  [Exception handler table]
  50 //  - handler entry point array
  51 //  [Implicit Null Pointer exception table]
  52 //  - implicit null table array
  53 
  54 class nmethod : public CompiledMethod {
  55   friend class VMStructs;
  56   friend class JVMCIVMStructs;
  57   friend class NMethodSweeper;
  58   friend class CodeCache;  // scavengable oops
  59  private:
  60 
  61   // Shared fields for all nmethod's
  62   int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method
  63   jmethodID _jmethod_id;       // Cache of method()->jmethod_id()
  64 
  65 #if INCLUDE_JVMCI
  66   // A weak reference to an InstalledCode object associated with
  67   // this nmethod.
  68   jweak     _jvmci_installed_code;
  69 
  70   // A weak reference to a SpeculationLog object associated with
  71   // this nmethod.
  72   jweak     _speculation_log;
  73 
  74   // Determines whether this nmethod is unloaded when the
  75   // referent in _jvmci_installed_code is cleared. This
  76   // will be false if the referent is initialized to a
  77   // HotSpotNMethod object whose isDefault field is true.
  78   // That is, installed code other than a "default"
  79   // HotSpotNMethod causes nmethod unloading.
  80   // This field is ignored once _jvmci_installed_code is NULL.
  81   bool _jvmci_installed_code_triggers_unloading;
  82 #endif
  83 
  84   // To support simple linked-list chaining of nmethods:
  85   nmethod*  _osr_link;         // from InstanceKlass::osr_nmethods_head
  86 
  87   static nmethod* volatile _oops_do_mark_nmethods;
  88   nmethod*        volatile _oops_do_mark_link;
  89 
  90   // offsets for entry points
  91   address _entry_point;                      // entry point with class check
  92   address _verified_entry_point;             // entry point without class check
  93   address _osr_entry_point;                  // entry point for on stack replacement
  94 
  95   // Offsets for different nmethod parts
  96   int  _exception_offset;
  97   // Offset of the unwind handler if it exists
  98   int _unwind_handler_offset;
  99 
 100   int _consts_offset;
 101   int _stub_offset;
 102   int _oops_offset;                       // offset to where embedded oop table begins (inside data)
 103   int _metadata_offset;                   // embedded meta data table
 104   int _scopes_data_offset;
 105   int _scopes_pcs_offset;
 106   int _dependencies_offset;
 107   int _handler_table_offset;
 108   int _nul_chk_table_offset;
 109   int _nmethod_end_offset;
 110 
 111   int code_offset() const { return (address) code_begin() - header_begin(); }
 112 
 113   // location in frame (offset for sp) that deopt can store the original
 114   // pc during a deopt.
 115   int _orig_pc_offset;
 116 
 117   int _compile_id;                           // which compilation made this nmethod
 118   int _comp_level;                           // compilation level
 119 
 120   // protected by CodeCache_lock
 121   bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)
 122 
 123   // used by jvmti to track if an unload event has been posted for this nmethod.
 124   bool _unload_reported;
 125 
 126   // Protected by Patching_lock
 127   volatile unsigned char _state;             // {in_use, not_entrant, zombie, unloaded}
 128 
 129 #ifdef ASSERT
 130   bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
 131 #endif
 132 
 133   jbyte _scavenge_root_state;
 134 
 135 #if INCLUDE_RTM_OPT
 136   // RTM state at compile time. Used during deoptimization to decide
 137   // whether to restart collecting RTM locking abort statistic again.
 138   RTMState _rtm_state;
 139 #endif
 140 
 141   // Nmethod Flushing lock. If non-zero, then the nmethod is not removed
 142   // and is not made into a zombie. However, once the nmethod is made into
 143   // a zombie, it will be locked one final time if CompiledMethodUnload
 144   // event processing needs to be done.
 145   volatile jint _lock_count;
 146 
 147   // not_entrant method removal. Each mark_sweep pass will update
 148   // this mark to current sweep invocation count if it is seen on the
 149   // stack.  An not_entrant method can be removed when there are no
 150   // more activations, i.e., when the _stack_traversal_mark is less than
 151   // current sweep traversal index.
 152   volatile long _stack_traversal_mark;
 153 
 154   // The _hotness_counter indicates the hotness of a method. The higher
 155   // the value the hotter the method. The hotness counter of a nmethod is
 156   // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method
 157   // is active while stack scanning (mark_active_nmethods()). The hotness
 158   // counter is decreased (by 1) while sweeping.
 159   int _hotness_counter;
 160 
 161   // These are used for compiled synchronized native methods to
 162   // locate the owner and stack slot for the BasicLock so that we can
 163   // properly revoke the bias of the owner if necessary. They are
 164   // needed because there is no debug information for compiled native
 165   // wrappers and the oop maps are insufficient to allow
 166   // frame::retrieve_receiver() to work. Currently they are expected
 167   // to be byte offsets from the Java stack pointer for maximum code
 168   // sharing between platforms. Note that currently biased locking
 169   // will never cause Class instances to be biased but this code
 170   // handles the static synchronized case as well.
 171   // JVMTI's GetLocalInstance() also uses these offsets to find the receiver
 172   // for non-static native wrapper frames.
 173   ByteSize _native_receiver_sp_offset;
 174   ByteSize _native_basic_lock_sp_offset;
 175 
 176   friend class nmethodLocker;
 177 
 178   // For native wrappers
 179   nmethod(Method* method,
 180           CompilerType type,
 181           int nmethod_size,
 182           int compile_id,
 183           CodeOffsets* offsets,
 184           CodeBuffer *code_buffer,
 185           int frame_size,
 186           ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */
 187           ByteSize basic_lock_sp_offset,       /* synchronized natives only */
 188           OopMapSet* oop_maps);
 189 
 190   // Creation support
 191   nmethod(Method* method,
 192           CompilerType type,
 193           int nmethod_size,
 194           int compile_id,
 195           int entry_bci,
 196           CodeOffsets* offsets,
 197           int orig_pc_offset,
 198           DebugInformationRecorder *recorder,
 199           Dependencies* dependencies,
 200           CodeBuffer *code_buffer,
 201           int frame_size,
 202           OopMapSet* oop_maps,
 203           ExceptionHandlerTable* handler_table,
 204           ImplicitExceptionTable* nul_chk_table,
 205           AbstractCompiler* compiler,
 206           int comp_level
 207 #if INCLUDE_JVMCI
 208           , jweak installed_code,
 209           jweak speculation_log
 210 #endif
 211           );
 212 
 213   // helper methods
 214   void* operator new(size_t size, int nmethod_size, int comp_level) throw();
 215 
 216   const char* reloc_string_for(u_char* begin, u_char* end);
 217   // Returns true if this thread changed the state of the nmethod or
 218   // false if another thread performed the transition.
 219   bool make_not_entrant_or_zombie(unsigned int state);
 220   bool make_entrant() { Unimplemented(); return false; }
 221   void inc_decompile_count();
 222 
 223   // Inform external interfaces that a compiled method has been unloaded
 224   void post_compiled_method_unload();
 225 
 226   // Initailize fields to their default values
 227   void init_defaults();
 228 
 229   // Offsets
 230   int content_offset() const                  { return content_begin() - header_begin(); }
 231   int data_offset() const                     { return _data_offset; }
 232 
 233   address header_end() const                  { return (address)    header_begin() + header_size(); }
 234 
 235  public:
 236   // create nmethod with entry_bci
 237   static nmethod* new_nmethod(const methodHandle& method,
 238                               int compile_id,
 239                               int entry_bci,
 240                               CodeOffsets* offsets,
 241                               int orig_pc_offset,
 242                               DebugInformationRecorder* recorder,
 243                               Dependencies* dependencies,
 244                               CodeBuffer *code_buffer,
 245                               int frame_size,
 246                               OopMapSet* oop_maps,
 247                               ExceptionHandlerTable* handler_table,
 248                               ImplicitExceptionTable* nul_chk_table,
 249                               AbstractCompiler* compiler,
 250                               int comp_level
 251 #if INCLUDE_JVMCI
 252                               , jweak installed_code = NULL,
 253                               jweak speculation_log = NULL
 254 #endif
 255   );
 256 
 257   static nmethod* new_native_nmethod(const methodHandle& method,
 258                                      int compile_id,
 259                                      CodeBuffer *code_buffer,
 260                                      int vep_offset,
 261                                      int frame_complete,
 262                                      int frame_size,
 263                                      ByteSize receiver_sp_offset,
 264                                      ByteSize basic_lock_sp_offset,
 265                                      OopMapSet* oop_maps);
 266 
 267   // type info
 268   bool is_nmethod() const                         { return true; }
 269   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }
 270 
 271   // boundaries for different parts
 272   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }
 273   address consts_end            () const          { return           code_begin()                           ; }
 274   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }
 275   address stub_end              () const          { return           header_begin() + _oops_offset          ; }
 276   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }
 277   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
 278   oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }
 279   oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }
 280 
 281   Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }
 282   Metadata** metadata_end     () const            { return (Metadata**)  _scopes_data_begin; }
 283 
 284   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }
 285   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }
 286   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
 287   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }
 288   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }
 289   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }
 290   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }
 291   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }
 292   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }
 293 
 294   // Sizes
 295   int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }
 296   int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }
 297   int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }
 298 
 299   int     oops_count() const { assert(oops_size() % oopSize == 0, "");  return (oops_size() / oopSize) + 1; }
 300   int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }
 301 
 302   int total_size        () const;
 303 
 304   void dec_hotness_counter()        { _hotness_counter--; }
 305   void set_hotness_counter(int val) { _hotness_counter = val; }
 306   int  hotness_counter() const      { return _hotness_counter; }
 307 
 308   // Containment
 309   bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }
 310   bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }
 311   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }
 312   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }
 313 
 314   // entry points
 315   address entry_point() const                     { return _entry_point;             } // normal entry point
 316   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 317 
 318   // flag accessing and manipulation
 319   bool  is_in_use() const                         { return _state == in_use; }
 320   bool  is_alive() const                          { unsigned char s = _state; return s < zombie; }
 321   bool  is_not_entrant() const                    { return _state == not_entrant; }
 322   bool  is_zombie() const                         { return _state == zombie; }
 323   bool  is_unloaded() const                       { return _state == unloaded; }
 324 
 325 #if INCLUDE_RTM_OPT
 326   // rtm state accessing and manipulating
 327   RTMState  rtm_state() const                     { return _rtm_state; }
 328   void set_rtm_state(RTMState state)              { _rtm_state = state; }
 329 #endif
 330 
 331   // Make the nmethod non entrant. The nmethod will continue to be
 332   // alive.  It is used when an uncommon trap happens.  Returns true
 333   // if this thread changed the state of the nmethod or false if
 334   // another thread performed the transition.
 335   bool  make_not_entrant() {
 336     assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
 337     return make_not_entrant_or_zombie(not_entrant);
 338   }
 339   bool  make_not_used()    { return make_not_entrant(); }
 340   bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }
 341 
 342   // used by jvmti to track if the unload event has been reported
 343   bool  unload_reported()                         { return _unload_reported; }
 344   void  set_unload_reported()                     { _unload_reported = true; }
 345 
 346   int get_state() const {
 347     return _state;
 348   }
 349 
 350   void  make_unloaded(BoolObjectClosure* is_alive, oop cause);
 351 
 352   bool has_dependencies()                         { return dependencies_size() != 0; }
 353   void flush_dependencies(BoolObjectClosure* is_alive);
 354   bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }
 355   void set_has_flushed_dependencies()             {
 356     assert(!has_flushed_dependencies(), "should only happen once");
 357     _has_flushed_dependencies = 1;
 358   }
 359 
 360   int   comp_level() const                        { return _comp_level; }
 361 
 362   // Support for oops in scopes and relocs:
 363   // Note: index 0 is reserved for null.
 364   oop   oop_at(int index) const                   { return index == 0 ? (oop) NULL: *oop_addr_at(index); }
 365   oop*  oop_addr_at(int index) const {  // for GC
 366     // relocation indexes are biased by 1 (because 0 is reserved)
 367     assert(index > 0 && index <= oops_count(), "must be a valid non-zero index");
 368     assert(!_oops_are_stale, "oops are stale");
 369     return &oops_begin()[index - 1];
 370   }
 371 
 372   // Support for meta data in scopes and relocs:
 373   // Note: index 0 is reserved for null.
 374   Metadata*     metadata_at(int index) const      { return index == 0 ? NULL: *metadata_addr_at(index); }
 375   Metadata**  metadata_addr_at(int index) const {  // for GC
 376     // relocation indexes are biased by 1 (because 0 is reserved)
 377     assert(index > 0 && index <= metadata_count(), "must be a valid non-zero index");
 378     return &metadata_begin()[index - 1];
 379   }
 380 
 381   void copy_values(GrowableArray<jobject>* oops);
 382   void copy_values(GrowableArray<Metadata*>* metadata);
 383 
 384   // Relocation support
 385 private:
 386   void fix_oop_relocations(address begin, address end, bool initialize_immediates);
 387   inline void initialize_immediate_oop(oop* dest, jobject handle);
 388 
 389 public:
 390   void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
 391   void fix_oop_relocations()                           { fix_oop_relocations(NULL, NULL, false); }
 392 
 393   // Scavengable oop support
 394   bool  on_scavenge_root_list() const                  { return (_scavenge_root_state & 1) != 0; }
 395  protected:
 396   enum { sl_on_list = 0x01, sl_marked = 0x10 };
 397   void  set_on_scavenge_root_list()                    { _scavenge_root_state = sl_on_list; }
 398   void  clear_on_scavenge_root_list()                  { _scavenge_root_state = 0; }
 399   // assertion-checking and pruning logic uses the bits of _scavenge_root_state
 400 #ifndef PRODUCT
 401   void  set_scavenge_root_marked()                     { _scavenge_root_state |= sl_marked; }
 402   void  clear_scavenge_root_marked()                   { _scavenge_root_state &= ~sl_marked; }
 403   bool  scavenge_root_not_marked()                     { return (_scavenge_root_state &~ sl_on_list) == 0; }
 404   // N.B. there is no positive marked query, and we only use the not_marked query for asserts.
 405 #endif //PRODUCT
 406   nmethod* scavenge_root_link() const                  { return _scavenge_root_link; }
 407   void     set_scavenge_root_link(nmethod *n)          { _scavenge_root_link = n; }
 408 
 409  public:
 410 
 411   // Sweeper support
 412   long  stack_traversal_mark()                    { return _stack_traversal_mark; }
 413   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }
 414 
 415   // implicit exceptions support
 416   address continuation_for_implicit_exception(address pc);
 417 
 418   // On-stack replacement support
 419   int   osr_entry_bci() const                     { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
 420   address  osr_entry() const                      { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
 421   void  invalidate_osr_method();
 422   nmethod* osr_link() const                       { return _osr_link; }
 423   void     set_osr_link(nmethod *n)               { _osr_link = n; }
 424 
 425   // Verify calls to dead methods have been cleaned.
 426   void verify_clean_inline_caches();
 427 
 428   // unlink and deallocate this nmethod
 429   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
 430   // expected to use any other private methods/data in this class.
 431 
 432  protected:
 433   void flush();
 434 
 435  public:
 436   // When true is returned, it is unsafe to remove this nmethod even if
 437   // it is a zombie, since the VM or the ServiceThread might still be
 438   // using it.
 439   bool is_locked_by_vm() const                    { return _lock_count >0; }
 440 
 441   // See comment at definition of _last_seen_on_stack
 442   void mark_as_seen_on_stack();
 443   bool can_convert_to_zombie();
 444 
 445   // Evolution support. We make old (discarded) compiled methods point to new Method*s.
 446   void set_method(Method* method) { _method = method; }
 447 
 448 #if INCLUDE_JVMCI
 449   // Gets the InstalledCode object associated with this nmethod
 450   // which may be NULL if this nmethod was not compiled by JVMCI
 451   // or the weak reference has been cleared.
 452   oop jvmci_installed_code();
 453 
 454   // Copies the value of the name field in the InstalledCode
 455   // object (if any) associated with this nmethod into buf.
 456   // Returns the value of buf if it was updated otherwise NULL.
 457   char* jvmci_installed_code_name(char* buf, size_t buflen);
 458 
 459   // Updates the state of the InstalledCode (if any) associated with
 460   // this nmethod based on the current value of _state.
 461   void maybe_invalidate_installed_code();
 462 
 463   // Deoptimizes the nmethod (if any) in the address field of a given
 464   // InstalledCode object. The address field is zeroed upon return.
 465   static void invalidate_installed_code(Handle installed_code, TRAPS);
 466 
 467   // Gets the SpeculationLog object associated with this nmethod
 468   // which may be NULL if this nmethod was not compiled by JVMCI
 469   // or the weak reference has been cleared.
 470   oop speculation_log();
 471 
 472  private:
 473   // Deletes the weak reference (if any) to the InstalledCode object
 474   // associated with this nmethod.
 475   void clear_jvmci_installed_code();
 476 
 477   // Deletes the weak reference (if any) to the SpeculationLog object
 478   // associated with this nmethod.
 479   void clear_speculation_log();
 480 
 481  public:
 482 #endif
 483 
 484  protected:
 485   virtual bool do_unloading_oops(address low_boundary, BoolObjectClosure* is_alive, bool unloading_occurred);
 486 #if INCLUDE_JVMCI
 487   // See comment for _jvmci_installed_code_triggers_unloading field.
 488   // Returns whether this nmethod was unloaded.
 489   virtual bool do_unloading_jvmci(BoolObjectClosure* is_alive, bool unloading_occurred);
 490 #endif
 491 
 492  private:
 493   bool do_unloading_scopes(BoolObjectClosure* is_alive, bool unloading_occurred);
 494   //  Unload a nmethod if the *root object is dead.
 495   bool can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred);
 496   bool unload_if_dead_at(RelocIterator *iter_at_oop, BoolObjectClosure* is_alive, bool unloading_occurred);
 497 
 498  public:
 499   void oops_do(OopClosure* f) { oops_do(f, false); }
 500   void oops_do(OopClosure* f, bool allow_zombie);
 501   bool detect_scavenge_root_oops();
 502   void verify_scavenge_root_oops() PRODUCT_RETURN;
 503 
 504   bool test_set_oops_do_mark();
 505   static void oops_do_marking_prologue();
 506   static void oops_do_marking_epilogue();
 507   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
 508   bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
 509 
 510  private:
 511   ScopeDesc* scope_desc_in(address begin, address end);
 512 
 513   address* orig_pc_addr(const frame* fr) { return (address*) ((address)fr->unextended_sp() + _orig_pc_offset); }
 514 
 515  public:
 516   // copying of debugging information
 517   void copy_scopes_pcs(PcDesc* pcs, int count);
 518   void copy_scopes_data(address buffer, int size);
 519 
 520   // Accessor/mutator for the original pc of a frame before a frame was deopted.
 521   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }
 522   void    set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }
 523 
 524   // jvmti support:
 525   void post_compiled_method_load_event();
 526   jmethodID get_and_cache_jmethod_id();
 527 
 528   // verify operations
 529   void verify();
 530   void verify_scopes();
 531   void verify_interrupt_point(address interrupt_point);
 532 
 533   // printing support
 534   void print()                          const;
 535   void print_relocations()                        PRODUCT_RETURN;
 536   void print_pcs()                                PRODUCT_RETURN;
 537   void print_scopes()                             PRODUCT_RETURN;
 538   void print_dependencies()                       PRODUCT_RETURN;
 539   void print_value_on(outputStream* st) const     PRODUCT_RETURN;
 540   void print_calls(outputStream* st)              PRODUCT_RETURN;
 541   void print_handler_table()                      PRODUCT_RETURN;
 542   void print_nul_chk_table()                      PRODUCT_RETURN;
 543   void print_recorded_oops()                      PRODUCT_RETURN;
 544   void print_recorded_metadata()                  PRODUCT_RETURN;
 545 
 546   void maybe_print_nmethod(DirectiveSet* directive);
 547   void print_nmethod(bool print_code);
 548 
 549   // need to re-define this from CodeBlob else the overload hides it
 550   virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
 551   void print_on(outputStream* st, const char* msg) const;
 552 
 553   // Logging
 554   void log_identity(xmlStream* log) const;
 555   void log_new_nmethod() const;
 556   void log_state_change() const;
 557 
 558   // Prints block-level comments, including nmethod specific block labels:
 559   virtual void print_block_comment(outputStream* stream, address block_begin) const {
 560     print_nmethod_labels(stream, block_begin);
 561     CodeBlob::print_block_comment(stream, block_begin);
 562   }
 563   void print_nmethod_labels(outputStream* stream, address block_begin) const;
 564 
 565   // Prints a comment for one native instruction (reloc info, pc desc)
 566   void print_code_comment_on(outputStream* st, int column, address begin, address end);
 567   static void print_statistics() PRODUCT_RETURN;
 568 
 569   // Compiler task identification.  Note that all OSR methods
 570   // are numbered in an independent sequence if CICountOSR is true,
 571   // and native method wrappers are also numbered independently if
 572   // CICountNative is true.
 573   virtual int compile_id() const { return _compile_id; }
 574   const char* compile_kind() const;
 575 
 576   // tells if any of this method's dependencies have been invalidated
 577   // (this is expensive!)
 578   static void check_all_dependencies(DepChange& changes);
 579 
 580   // tells if this compiled method is dependent on the given changes,
 581   // and the changes have invalidated it
 582   bool check_dependency_on(DepChange& changes);
 583 
 584   // Evolution support. Tells if this compiled method is dependent on any of
 585   // methods m() of class dependee, such that if m() in dependee is replaced,
 586   // this compiled method will have to be deoptimized.
 587   bool is_evol_dependent_on(Klass* dependee);
 588 
 589   // Fast breakpoint support. Tells if this compiled method is
 590   // dependent on the given method. Returns true if this nmethod
 591   // corresponds to the given method as well.
 592   virtual bool is_dependent_on_method(Method* dependee);
 593 
 594   // is it ok to patch at address?
 595   bool is_patchable_at(address instr_address);
 596 
 597   // UseBiasedLocking support
 598   ByteSize native_receiver_sp_offset() {
 599     return _native_receiver_sp_offset;
 600   }
 601   ByteSize native_basic_lock_sp_offset() {
 602     return _native_basic_lock_sp_offset;
 603   }
 604 
 605   // support for code generation
 606   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }
 607   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }
 608   static int state_offset()                       { return offset_of(nmethod, _state); }
 609 
 610   virtual void metadata_do(void f(Metadata*));
 611 
 612   NativeCallWrapper* call_wrapper_at(address call) const;
 613   NativeCallWrapper* call_wrapper_before(address return_pc) const;
 614   address call_instruction_address(address pc) const;
 615 
 616   virtual CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) const;
 617   virtual CompiledStaticCall* compiledStaticCall_at(address addr) const;
 618   virtual CompiledStaticCall* compiledStaticCall_before(address addr) const;
 619 };
 620 
 621 // Locks an nmethod so its code will not get removed and it will not
 622 // be made into a zombie, even if it is a not_entrant method. After the
 623 // nmethod becomes a zombie, if CompiledMethodUnload event processing
 624 // needs to be done, then lock_nmethod() is used directly to keep the
 625 // generated code from being reused too early.
 626 class nmethodLocker : public StackObj {
 627   CompiledMethod* _nm;
 628 
 629  public:
 630 
 631   // note: nm can be NULL
 632   // Only JvmtiDeferredEvent::compiled_method_unload_event()
 633   // should pass zombie_ok == true.
 634   static void lock_nmethod(CompiledMethod* nm, bool zombie_ok = false);
 635   static void unlock_nmethod(CompiledMethod* nm); // (ditto)
 636 
 637   nmethodLocker(address pc); // derive nm from pc
 638   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
 639   nmethodLocker(CompiledMethod *nm) {
 640     _nm = nm;
 641     lock(_nm);
 642   }
 643 
 644   static void lock(CompiledMethod* method) {
 645     if (method == NULL) return;
 646     lock_nmethod(method);
 647   }
 648 
 649   static void unlock(CompiledMethod* method) {
 650     if (method == NULL) return;
 651     unlock_nmethod(method);
 652   }
 653 
 654   nmethodLocker() { _nm = NULL; }
 655   ~nmethodLocker() {
 656     unlock(_nm);
 657   }
 658 
 659   CompiledMethod* code() { return _nm; }
 660   void set_code(CompiledMethod* new_nm) {
 661     unlock(_nm);   // note:  This works even if _nm==new_nm.
 662     _nm = new_nm;
 663     lock(_nm);
 664   }
 665 };
 666 
 667 #endif // SHARE_VM_CODE_NMETHOD_HPP