1 /*
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   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).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  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
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  24 
  25 #ifndef SHARE_CODE_NMETHOD_HPP
  26 #define SHARE_CODE_NMETHOD_HPP
  27 
  28 #include "code/compiledMethod.hpp"
  29 
  30 class DepChange;
  31 class DirectiveSet;
  32 class DebugInformationRecorder;
  33 
  34 // nmethods (native methods) are the compiled code versions of Java methods.
  35 //
  36 // An nmethod contains:
  37 //  - header                 (the nmethod structure)
  38 //  [Relocation]
  39 //  - relocation information
  40 //  - constant part          (doubles, longs and floats used in nmethod)
  41 //  - oop table
  42 //  [Code]
  43 //  - code body
  44 //  - exception handler
  45 //  - stub code
  46 //  [Debugging information]
  47 //  - oop array
  48 //  - data array
  49 //  - pcs
  50 //  [Exception handler table]
  51 //  - handler entry point array
  52 //  [Implicit Null Pointer exception table]
  53 //  - implicit null table array
  54 //  [Speculations]
  55 //  - encoded speculations array
  56 //  [JVMCINMethodData]
  57 //  - meta data for JVMCI compiled nmethod
  58 
  59 #if INCLUDE_JVMCI
  60 class FailedSpeculation;
  61 class JVMCINMethodData;
  62 #endif
  63 
  64 class nmethod : public CompiledMethod {
  65   friend class VMStructs;
  66   friend class JVMCIVMStructs;
  67   friend class NMethodSweeper;
  68   friend class CodeCache;  // scavengable oops
  69   friend class JVMCINMethodData;
  70  private:
  71 
  72   // Shared fields for all nmethod's
  73   int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method
  74   jmethodID _jmethod_id;       // Cache of method()->jmethod_id()
  75 
  76   // To support simple linked-list chaining of nmethods:
  77   nmethod*  _osr_link;         // from InstanceKlass::osr_nmethods_head
  78 
  79   static nmethod* volatile _oops_do_mark_nmethods;
  80   nmethod*        volatile _oops_do_mark_link;
  81 
  82   // offsets for entry points
  83   address _entry_point;                      // entry point with class check
  84   address _verified_entry_point;             // entry point without class check
  85   address _osr_entry_point;                  // entry point for on stack replacement
  86 
  87   // Offsets for different nmethod parts
  88   int  _exception_offset;
  89   // Offset of the unwind handler if it exists
  90   int _unwind_handler_offset;
  91 
  92   int _consts_offset;
  93   int _stub_offset;
  94   int _oops_offset;                       // offset to where embedded oop table begins (inside data)
  95   int _metadata_offset;                   // embedded meta data table
  96   int _scopes_data_offset;
  97   int _scopes_pcs_offset;
  98   int _dependencies_offset;
  99   int _handler_table_offset;
 100   int _nul_chk_table_offset;
 101 #if INCLUDE_JVMCI
 102   int _speculations_offset;
 103   int _jvmci_data_offset;
 104 #endif
 105   int _nmethod_end_offset;
 106 
 107   int code_offset() const { return (address) code_begin() - header_begin(); }
 108 
 109   // location in frame (offset for sp) that deopt can store the original
 110   // pc during a deopt.
 111   int _orig_pc_offset;
 112 
 113   int _compile_id;                           // which compilation made this nmethod
 114   int _comp_level;                           // compilation level
 115 
 116   // protected by CodeCache_lock
 117   bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)
 118 
 119   // used by jvmti to track if an unload event has been posted for this nmethod.
 120   bool _unload_reported;
 121 
 122   // Protected by CompiledMethod_lock
 123   volatile signed char _state;               // {not_installed, in_use, not_entrant, zombie, unloaded}
 124 
 125 #ifdef ASSERT
 126   bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
 127 #endif
 128 
 129 #if INCLUDE_RTM_OPT
 130   // RTM state at compile time. Used during deoptimization to decide
 131   // whether to restart collecting RTM locking abort statistic again.
 132   RTMState _rtm_state;
 133 #endif
 134 
 135   // Nmethod Flushing lock. If non-zero, then the nmethod is not removed
 136   // and is not made into a zombie. However, once the nmethod is made into
 137   // a zombie, it will be locked one final time if CompiledMethodUnload
 138   // event processing needs to be done.
 139   volatile jint _lock_count;
 140 
 141   // not_entrant method removal. Each mark_sweep pass will update
 142   // this mark to current sweep invocation count if it is seen on the
 143   // stack.  An not_entrant method can be removed when there are no
 144   // more activations, i.e., when the _stack_traversal_mark is less than
 145   // current sweep traversal index.
 146   volatile long _stack_traversal_mark;
 147 
 148   // The _hotness_counter indicates the hotness of a method. The higher
 149   // the value the hotter the method. The hotness counter of a nmethod is
 150   // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method
 151   // is active while stack scanning (mark_active_nmethods()). The hotness
 152   // counter is decreased (by 1) while sweeping.
 153   int _hotness_counter;
 154 
 155   // Local state used to keep track of whether unloading is happening or not
 156   volatile uint8_t _is_unloading_state;
 157 
 158   // These are used for compiled synchronized native methods to
 159   // locate the owner and stack slot for the BasicLock so that we can
 160   // properly revoke the bias of the owner if necessary. They are
 161   // needed because there is no debug information for compiled native
 162   // wrappers and the oop maps are insufficient to allow
 163   // frame::retrieve_receiver() to work. Currently they are expected
 164   // to be byte offsets from the Java stack pointer for maximum code
 165   // sharing between platforms. Note that currently biased locking
 166   // will never cause Class instances to be biased but this code
 167   // handles the static synchronized case as well.
 168   // JVMTI's GetLocalInstance() also uses these offsets to find the receiver
 169   // for non-static native wrapper frames.
 170   ByteSize _native_receiver_sp_offset;
 171   ByteSize _native_basic_lock_sp_offset;
 172 
 173   friend class nmethodLocker;
 174 
 175   // For native wrappers
 176   nmethod(Method* method,
 177           CompilerType type,
 178           int nmethod_size,
 179           int compile_id,
 180           CodeOffsets* offsets,
 181           CodeBuffer *code_buffer,
 182           int frame_size,
 183           ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */
 184           ByteSize basic_lock_sp_offset,       /* synchronized natives only */
 185           OopMapSet* oop_maps);
 186 
 187   // Creation support
 188   nmethod(Method* method,
 189           CompilerType type,
 190           int nmethod_size,
 191           int compile_id,
 192           int entry_bci,
 193           CodeOffsets* offsets,
 194           int orig_pc_offset,
 195           DebugInformationRecorder *recorder,
 196           Dependencies* dependencies,
 197           CodeBuffer *code_buffer,
 198           int frame_size,
 199           OopMapSet* oop_maps,
 200           ExceptionHandlerTable* handler_table,
 201           ImplicitExceptionTable* nul_chk_table,
 202           AbstractCompiler* compiler,
 203           int comp_level
 204 #if INCLUDE_JVMCI
 205           , char* speculations,
 206           int speculations_len,
 207           int jvmci_data_size
 208 #endif
 209           );
 210 
 211   // helper methods
 212   void* operator new(size_t size, int nmethod_size, int comp_level) throw();
 213 
 214   const char* reloc_string_for(u_char* begin, u_char* end);
 215   // Returns true if this thread changed the state of the nmethod or
 216   // false if another thread performed the transition.
 217   bool make_not_entrant_or_zombie(int state);
 218   bool make_entrant() { Unimplemented(); return false; }
 219   void inc_decompile_count();
 220 
 221   // Inform external interfaces that a compiled method has been unloaded
 222   void post_compiled_method_unload();
 223 
 224   // Initailize fields to their default values
 225   void init_defaults();
 226 
 227   // Offsets
 228   int content_offset() const                  { return content_begin() - header_begin(); }
 229   int data_offset() const                     { return _data_offset; }
 230 
 231   address header_end() const                  { return (address)    header_begin() + header_size(); }
 232 
 233  public:
 234   // create nmethod with entry_bci
 235   static nmethod* new_nmethod(const methodHandle& method,
 236                               int compile_id,
 237                               int entry_bci,
 238                               CodeOffsets* offsets,
 239                               int orig_pc_offset,
 240                               DebugInformationRecorder* recorder,
 241                               Dependencies* dependencies,
 242                               CodeBuffer *code_buffer,
 243                               int frame_size,
 244                               OopMapSet* oop_maps,
 245                               ExceptionHandlerTable* handler_table,
 246                               ImplicitExceptionTable* nul_chk_table,
 247                               AbstractCompiler* compiler,
 248                               int comp_level
 249 #if INCLUDE_JVMCI
 250                               , char* speculations = NULL,
 251                               int speculations_len = 0,
 252                               int nmethod_mirror_index = -1,
 253                               const char* nmethod_mirror_name = NULL,
 254                               FailedSpeculation** failed_speculations = NULL
 255 #endif
 256   );
 257 
 258   // Only used for unit tests.
 259   nmethod()
 260     : CompiledMethod(),
 261       _is_unloading_state(0),
 262       _native_receiver_sp_offset(in_ByteSize(-1)),
 263       _native_basic_lock_sp_offset(in_ByteSize(-1)) {}
 264 
 265 
 266   static nmethod* new_native_nmethod(const methodHandle& method,
 267                                      int compile_id,
 268                                      CodeBuffer *code_buffer,
 269                                      int vep_offset,
 270                                      int frame_complete,
 271                                      int frame_size,
 272                                      ByteSize receiver_sp_offset,
 273                                      ByteSize basic_lock_sp_offset,
 274                                      OopMapSet* oop_maps);
 275 
 276   // type info
 277   bool is_nmethod() const                         { return true; }
 278   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }
 279 
 280   // boundaries for different parts
 281   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }
 282   address consts_end            () const          { return           code_begin()                           ; }
 283   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }
 284   address stub_end              () const          { return           header_begin() + _oops_offset          ; }
 285   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }
 286   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
 287   oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }
 288   oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }
 289 
 290   Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }
 291   Metadata** metadata_end     () const            { return (Metadata**)  _scopes_data_begin; }
 292 
 293   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }
 294   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }
 295   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
 296   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }
 297   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }
 298   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }
 299   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }
 300   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }
 301 #if INCLUDE_JVMCI
 302   address nul_chk_table_end     () const          { return           header_begin() + _speculations_offset  ; }
 303   address speculations_begin    () const          { return           header_begin() + _speculations_offset  ; }
 304   address speculations_end      () const          { return           header_begin() + _jvmci_data_offset   ; }
 305   address jvmci_data_begin      () const          { return           header_begin() + _jvmci_data_offset    ; }
 306   address jvmci_data_end        () const          { return           header_begin() + _nmethod_end_offset   ; }
 307 #else
 308   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }
 309 #endif
 310 
 311   // Sizes
 312   int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }
 313   int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }
 314   int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }
 315 #if INCLUDE_JVMCI
 316   int speculations_size () const                  { return            speculations_end () -            speculations_begin (); }
 317   int jvmci_data_size   () const                  { return            jvmci_data_end   () -            jvmci_data_begin   (); }
 318 #endif
 319 
 320   int     oops_count() const { assert(oops_size() % oopSize == 0, "");  return (oops_size() / oopSize) + 1; }
 321   int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }
 322 
 323   int total_size        () const;
 324 
 325   void dec_hotness_counter()        { _hotness_counter--; }
 326   void set_hotness_counter(int val) { _hotness_counter = val; }
 327   int  hotness_counter() const      { return _hotness_counter; }
 328 
 329   // Containment
 330   bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }
 331   bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }
 332   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }
 333   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }
 334 
 335   // entry points
 336   address entry_point() const                     { return _entry_point;             } // normal entry point
 337   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 338 
 339   // flag accessing and manipulation
 340   bool  is_not_installed() const                  { return _state == not_installed; }
 341   bool  is_in_use() const                         { return _state <= in_use; }
 342   bool  is_alive() const                          { return _state < zombie; }
 343   bool  is_not_entrant() const                    { return _state == not_entrant; }
 344   bool  is_zombie() const                         { return _state == zombie; }
 345   bool  is_unloaded() const                       { return _state == unloaded; }
 346 
 347   void clear_unloading_state();
 348   virtual bool is_unloading();
 349   virtual void do_unloading(bool unloading_occurred);
 350 
 351 #if INCLUDE_RTM_OPT
 352   // rtm state accessing and manipulating
 353   RTMState  rtm_state() const                     { return _rtm_state; }
 354   void set_rtm_state(RTMState state)              { _rtm_state = state; }
 355 #endif
 356 
 357   void make_in_use()                              { _state = in_use; }
 358   // Make the nmethod non entrant. The nmethod will continue to be
 359   // alive.  It is used when an uncommon trap happens.  Returns true
 360   // if this thread changed the state of the nmethod or false if
 361   // another thread performed the transition.
 362   bool  make_not_entrant() {
 363     assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
 364     return make_not_entrant_or_zombie(not_entrant);
 365   }
 366   bool  make_not_used()    { return make_not_entrant(); }
 367   bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }
 368 
 369   // used by jvmti to track if the unload event has been reported
 370   bool  unload_reported()                         { return _unload_reported; }
 371   void  set_unload_reported()                     { _unload_reported = true; }
 372 
 373   int get_state() const {
 374     return _state;
 375   }
 376 
 377   void  make_unloaded();
 378 
 379   bool has_dependencies()                         { return dependencies_size() != 0; }
 380   void print_dependencies()                       PRODUCT_RETURN;
 381   void flush_dependencies(bool delete_immediately);
 382   bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }
 383   void set_has_flushed_dependencies()             {
 384     assert(!has_flushed_dependencies(), "should only happen once");
 385     _has_flushed_dependencies = 1;
 386   }
 387 
 388   int   comp_level() const                        { return _comp_level; }
 389 
 390   void unlink_from_method();
 391 
 392   // Support for oops in scopes and relocs:
 393   // Note: index 0 is reserved for null.
 394   oop   oop_at(int index) const;
 395   oop*  oop_addr_at(int index) const {  // for GC
 396     // relocation indexes are biased by 1 (because 0 is reserved)
 397     assert(index > 0 && index <= oops_count(), "must be a valid non-zero index");
 398     assert(!_oops_are_stale, "oops are stale");
 399     return &oops_begin()[index - 1];
 400   }
 401 
 402   // Support for meta data in scopes and relocs:
 403   // Note: index 0 is reserved for null.
 404   Metadata*     metadata_at(int index) const      { return index == 0 ? NULL: *metadata_addr_at(index); }
 405   Metadata**  metadata_addr_at(int index) const {  // for GC
 406     // relocation indexes are biased by 1 (because 0 is reserved)
 407     assert(index > 0 && index <= metadata_count(), "must be a valid non-zero index");
 408     return &metadata_begin()[index - 1];
 409   }
 410 
 411   void copy_values(GrowableArray<jobject>* oops);
 412   void copy_values(GrowableArray<Metadata*>* metadata);
 413 
 414   // Relocation support
 415 private:
 416   void fix_oop_relocations(address begin, address end, bool initialize_immediates);
 417   inline void initialize_immediate_oop(oop* dest, jobject handle);
 418 
 419 public:
 420   void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
 421   void fix_oop_relocations()                           { fix_oop_relocations(NULL, NULL, false); }
 422 
 423   // Sweeper support
 424   long  stack_traversal_mark()                    { return _stack_traversal_mark; }
 425   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }
 426 
 427   // On-stack replacement support
 428   int   osr_entry_bci() const                     { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
 429   address  osr_entry() const                      { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
 430   void  invalidate_osr_method();
 431   nmethod* osr_link() const                       { return _osr_link; }
 432   void     set_osr_link(nmethod *n)               { _osr_link = n; }
 433 
 434   // Verify calls to dead methods have been cleaned.
 435   void verify_clean_inline_caches();
 436 
 437   // unlink and deallocate this nmethod
 438   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
 439   // expected to use any other private methods/data in this class.
 440 
 441  protected:
 442   void flush();
 443 
 444  public:
 445   // When true is returned, it is unsafe to remove this nmethod even if
 446   // it is a zombie, since the VM or the ServiceThread might still be
 447   // using it.
 448   bool is_locked_by_vm() const                    { return _lock_count >0; }
 449 
 450   // See comment at definition of _last_seen_on_stack
 451   void mark_as_seen_on_stack();
 452   bool can_convert_to_zombie();
 453 
 454   // Evolution support. We make old (discarded) compiled methods point to new Method*s.
 455   void set_method(Method* method) { _method = method; }
 456 
 457 #if INCLUDE_JVMCI
 458   // Gets the JVMCI name of this nmethod.
 459   const char* jvmci_name();
 460 
 461   // Records the pending failed speculation in the
 462   // JVMCI speculation log associated with this nmethod.
 463   void update_speculation(JavaThread* thread);
 464 
 465   // Gets the data specific to a JVMCI compiled method.
 466   // This returns a non-NULL value iff this nmethod was
 467   // compiled by the JVMCI compiler.
 468   JVMCINMethodData* jvmci_nmethod_data() const {
 469     return jvmci_data_size() == 0 ? NULL : (JVMCINMethodData*) jvmci_data_begin();
 470   }
 471 #endif
 472 
 473  public:
 474   void oops_do(OopClosure* f) { oops_do(f, false); }
 475   void oops_do(OopClosure* f, bool allow_zombie);
 476 
 477   bool test_set_oops_do_mark();
 478   static void oops_do_marking_prologue();
 479   static void oops_do_marking_epilogue();
 480   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
 481   bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
 482 
 483  private:
 484   ScopeDesc* scope_desc_in(address begin, address end);
 485 
 486   address* orig_pc_addr(const frame* fr);
 487 
 488  public:
 489   // copying of debugging information
 490   void copy_scopes_pcs(PcDesc* pcs, int count);
 491   void copy_scopes_data(address buffer, int size);
 492 
 493   // Accessor/mutator for the original pc of a frame before a frame was deopted.
 494   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }
 495   void    set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }
 496 
 497   // jvmti support:
 498   void post_compiled_method_load_event();
 499   jmethodID get_and_cache_jmethod_id();
 500 
 501   // verify operations
 502   void verify();
 503   void verify_scopes();
 504   void verify_interrupt_point(address interrupt_point);
 505 
 506   // Disassemble this nmethod with additional debug information, e.g. information about blocks.
 507   void decode2(outputStream* st) const;
 508   void print_constant_pool(outputStream* st);
 509 
 510   // Avoid hiding of parent's 'decode(outputStream*)' method.
 511   void decode(outputStream* st) const { decode2(st); } // just delegate here.
 512 
 513   // printing support
 514   void print()                          const;
 515   void print(outputStream* st)          const;
 516   void print_code();
 517 
 518 #if defined(SUPPORT_DATA_STRUCTS)
 519   // print output in opt build for disassembler library
 520   void print_relocations()                        PRODUCT_RETURN;
 521   void print_pcs() { print_pcs_on(tty); }
 522   void print_pcs_on(outputStream* st);
 523   void print_scopes() { print_scopes_on(tty); }
 524   void print_scopes_on(outputStream* st)          PRODUCT_RETURN;
 525   void print_value_on(outputStream* st) const;
 526   void print_handler_table();
 527   void print_nul_chk_table();
 528   void print_recorded_oops();
 529   void print_recorded_metadata();
 530 
 531   void print_oops(outputStream* st);     // oops from the underlying CodeBlob.
 532   void print_metadata(outputStream* st); // metadata in metadata pool.
 533 #else
 534   // void print_pcs()                             PRODUCT_RETURN;
 535   void print_pcs()                                { return; }
 536 #endif
 537 
 538   void print_calls(outputStream* st)              PRODUCT_RETURN;
 539   static void print_statistics()                  PRODUCT_RETURN;
 540 
 541   void maybe_print_nmethod(DirectiveSet* directive);
 542   void print_nmethod(bool print_code);
 543 
 544   // need to re-define this from CodeBlob else the overload hides it
 545   virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
 546   void print_on(outputStream* st, const char* msg) const;
 547 
 548   // Logging
 549   void log_identity(xmlStream* log) const;
 550   void log_new_nmethod() const;
 551   void log_state_change() const;
 552 
 553   // Prints block-level comments, including nmethod specific block labels:
 554   virtual void print_block_comment(outputStream* stream, address block_begin) const {
 555 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
 556     print_nmethod_labels(stream, block_begin);
 557     CodeBlob::print_block_comment(stream, block_begin);
 558 #endif
 559   }
 560   bool has_block_comment(address block_begin) {
 561     return CodeBlob::has_block_comment(block_begin);
 562   }
 563   void print_nmethod_labels(outputStream* stream, address block_begin, bool print_section_labels=true) const;
 564   const char* nmethod_section_label(address pos) const;
 565 
 566   // returns whether this nmethod has code comments.
 567   bool has_code_comment(address begin, address end);
 568   // Prints a comment for one native instruction (reloc info, pc desc)
 569   void print_code_comment_on(outputStream* st, int column, address begin, address end);
 570 
 571   // Compiler task identification.  Note that all OSR methods
 572   // are numbered in an independent sequence if CICountOSR is true,
 573   // and native method wrappers are also numbered independently if
 574   // CICountNative is true.
 575   virtual int compile_id() const { return _compile_id; }
 576   const char* compile_kind() const;
 577 
 578   // tells if any of this method's dependencies have been invalidated
 579   // (this is expensive!)
 580   static void check_all_dependencies(DepChange& changes);
 581 
 582   // tells if this compiled method is dependent on the given changes,
 583   // and the changes have invalidated it
 584   bool check_dependency_on(DepChange& changes);
 585 
 586   // Fast breakpoint support. Tells if this compiled method is
 587   // dependent on the given method. Returns true if this nmethod
 588   // corresponds to the given method as well.
 589   virtual bool is_dependent_on_method(Method* dependee);
 590 
 591   // is it ok to patch at address?
 592   bool is_patchable_at(address instr_address);
 593 
 594   // UseBiasedLocking support
 595   ByteSize native_receiver_sp_offset() {
 596     return _native_receiver_sp_offset;
 597   }
 598   ByteSize native_basic_lock_sp_offset() {
 599     return _native_basic_lock_sp_offset;
 600   }
 601 
 602   // support for code generation
 603   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }
 604   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }
 605   static int state_offset()                       { return offset_of(nmethod, _state); }
 606 
 607   virtual void metadata_do(MetadataClosure* f);
 608 
 609   NativeCallWrapper* call_wrapper_at(address call) const;
 610   NativeCallWrapper* call_wrapper_before(address return_pc) const;
 611   address call_instruction_address(address pc) const;
 612 
 613   virtual CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) const;
 614   virtual CompiledStaticCall* compiledStaticCall_at(address addr) const;
 615   virtual CompiledStaticCall* compiledStaticCall_before(address addr) const;
 616 };
 617 
 618 // Locks an nmethod so its code will not get removed and it will not
 619 // be made into a zombie, even if it is a not_entrant method. After the
 620 // nmethod becomes a zombie, if CompiledMethodUnload event processing
 621 // needs to be done, then lock_nmethod() is used directly to keep the
 622 // generated code from being reused too early.
 623 class nmethodLocker : public StackObj {
 624   CompiledMethod* _nm;
 625 
 626  public:
 627 
 628   // note: nm can be NULL
 629   // Only JvmtiDeferredEvent::compiled_method_unload_event()
 630   // should pass zombie_ok == true.
 631   static void lock_nmethod(CompiledMethod* nm, bool zombie_ok = false);
 632   static void unlock_nmethod(CompiledMethod* nm); // (ditto)
 633 
 634   nmethodLocker(address pc); // derive nm from pc
 635   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
 636   nmethodLocker(CompiledMethod *nm) {
 637     _nm = nm;
 638     lock(_nm);
 639   }
 640 
 641   static void lock(CompiledMethod* method) {
 642     if (method == NULL) return;
 643     lock_nmethod(method);
 644   }
 645 
 646   static void unlock(CompiledMethod* method) {
 647     if (method == NULL) return;
 648     unlock_nmethod(method);
 649   }
 650 
 651   nmethodLocker() { _nm = NULL; }
 652   ~nmethodLocker() {
 653     unlock(_nm);
 654   }
 655 
 656   CompiledMethod* code() { return _nm; }
 657   void set_code(CompiledMethod* new_nm) {
 658     unlock(_nm);   // note:  This works even if _nm==new_nm.
 659     _nm = new_nm;
 660     lock(_nm);
 661   }
 662 };
 663 
 664 #endif // SHARE_CODE_NMETHOD_HPP