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.
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   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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  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 
 216   bool try_transition(int new_state);
 217 
 218   // Returns true if this thread changed the state of the nmethod or
 219   // false if another thread performed the transition.
 220   bool make_not_entrant_or_zombie(int state);
 221   bool make_entrant() { Unimplemented(); return false; }
 222   void inc_decompile_count();
 223 
 224   // Inform external interfaces that a compiled method has been unloaded
 225   void post_compiled_method_unload();
 226 
 227   // Initailize fields to their default values
 228   void init_defaults();
 229 
 230   // Offsets
 231   int content_offset() const                  { return content_begin() - header_begin(); }
 232   int data_offset() const                     { return _data_offset; }
 233 
 234   address header_end() const                  { return (address)    header_begin() + header_size(); }
 235 
 236  public:
 237   // create nmethod with entry_bci
 238   static nmethod* new_nmethod(const methodHandle& method,
 239                               int compile_id,
 240                               int entry_bci,
 241                               CodeOffsets* offsets,
 242                               int orig_pc_offset,
 243                               DebugInformationRecorder* recorder,
 244                               Dependencies* dependencies,
 245                               CodeBuffer *code_buffer,
 246                               int frame_size,
 247                               OopMapSet* oop_maps,
 248                               ExceptionHandlerTable* handler_table,
 249                               ImplicitExceptionTable* nul_chk_table,
 250                               AbstractCompiler* compiler,
 251                               int comp_level
 252 #if INCLUDE_JVMCI
 253                               , char* speculations = NULL,
 254                               int speculations_len = 0,
 255                               int nmethod_mirror_index = -1,
 256                               const char* nmethod_mirror_name = NULL,
 257                               FailedSpeculation** failed_speculations = NULL
 258 #endif
 259   );
 260 
 261   // Only used for unit tests.
 262   nmethod()
 263     : CompiledMethod(),
 264       _is_unloading_state(0),
 265       _native_receiver_sp_offset(in_ByteSize(-1)),
 266       _native_basic_lock_sp_offset(in_ByteSize(-1)) {}
 267 
 268 
 269   static nmethod* new_native_nmethod(const methodHandle& method,
 270                                      int compile_id,
 271                                      CodeBuffer *code_buffer,
 272                                      int vep_offset,
 273                                      int frame_complete,
 274                                      int frame_size,
 275                                      ByteSize receiver_sp_offset,
 276                                      ByteSize basic_lock_sp_offset,
 277                                      OopMapSet* oop_maps);
 278 
 279   // type info
 280   bool is_nmethod() const                         { return true; }
 281   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }
 282 
 283   // boundaries for different parts
 284   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }
 285   address consts_end            () const          { return           code_begin()                           ; }
 286   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }
 287   address stub_end              () const          { return           header_begin() + _oops_offset          ; }
 288   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }
 289   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
 290   oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }
 291   oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }
 292 
 293   Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }
 294   Metadata** metadata_end     () const            { return (Metadata**)  _scopes_data_begin; }
 295 
 296   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }
 297   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }
 298   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
 299   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }
 300   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }
 301   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }
 302   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }
 303   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }
 304 #if INCLUDE_JVMCI
 305   address nul_chk_table_end     () const          { return           header_begin() + _speculations_offset  ; }
 306   address speculations_begin    () const          { return           header_begin() + _speculations_offset  ; }
 307   address speculations_end      () const          { return           header_begin() + _jvmci_data_offset   ; }
 308   address jvmci_data_begin      () const          { return           header_begin() + _jvmci_data_offset    ; }
 309   address jvmci_data_end        () const          { return           header_begin() + _nmethod_end_offset   ; }
 310 #else
 311   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }
 312 #endif
 313 
 314   // Sizes
 315   int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }
 316   int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }
 317   int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }
 318 #if INCLUDE_JVMCI
 319   int speculations_size () const                  { return            speculations_end () -            speculations_begin (); }
 320   int jvmci_data_size   () const                  { return            jvmci_data_end   () -            jvmci_data_begin   (); }
 321 #endif
 322 
 323   int     oops_count() const { assert(oops_size() % oopSize == 0, "");  return (oops_size() / oopSize) + 1; }
 324   int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }
 325 
 326   int total_size        () const;
 327 
 328   void dec_hotness_counter()        { _hotness_counter--; }
 329   void set_hotness_counter(int val) { _hotness_counter = val; }
 330   int  hotness_counter() const      { return _hotness_counter; }
 331 
 332   // Containment
 333   bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }
 334   bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }
 335   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }
 336   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }
 337 
 338   // entry points
 339   address entry_point() const                     { return _entry_point;             } // normal entry point
 340   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 341 
 342   // flag accessing and manipulation
 343   bool  is_not_installed() const                  { return _state == not_installed; }
 344   bool  is_in_use() const                         { return _state <= in_use; }
 345   bool  is_alive() const                          { return _state < unloaded; }
 346   bool  is_not_entrant() const                    { return _state == not_entrant; }
 347   bool  is_zombie() const                         { return _state == zombie; }
 348   bool  is_unloaded() const                       { return _state == unloaded; }
 349 
 350   void clear_unloading_state();
 351   virtual bool is_unloading();
 352   virtual void do_unloading(bool unloading_occurred);
 353 
 354 #if INCLUDE_RTM_OPT
 355   // rtm state accessing and manipulating
 356   RTMState  rtm_state() const                     { return _rtm_state; }
 357   void set_rtm_state(RTMState state)              { _rtm_state = state; }
 358 #endif
 359 
 360   bool make_in_use() {
 361     return try_transition(in_use);
 362   }
 363   // Make the nmethod non entrant. The nmethod will continue to be
 364   // alive.  It is used when an uncommon trap happens.  Returns true
 365   // if this thread changed the state of the nmethod or false if
 366   // another thread performed the transition.
 367   bool  make_not_entrant() {
 368     assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
 369     return make_not_entrant_or_zombie(not_entrant);
 370   }
 371   bool  make_not_used()    { return make_not_entrant(); }
 372   bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }
 373 
 374   // used by jvmti to track if the unload event has been reported
 375   bool  unload_reported()                         { return _unload_reported; }
 376   void  set_unload_reported()                     { _unload_reported = true; }
 377 
 378   int get_state() const {
 379     return _state;
 380   }
 381 
 382   void  make_unloaded();
 383 
 384   bool has_dependencies()                         { return dependencies_size() != 0; }
 385   void print_dependencies()                       PRODUCT_RETURN;
 386   void flush_dependencies(bool delete_immediately);
 387   bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }
 388   void set_has_flushed_dependencies()             {
 389     assert(!has_flushed_dependencies(), "should only happen once");
 390     _has_flushed_dependencies = 1;
 391   }
 392 
 393   int   comp_level() const                        { return _comp_level; }
 394 
 395   void unlink_from_method();
 396 
 397   // Support for oops in scopes and relocs:
 398   // Note: index 0 is reserved for null.
 399   oop   oop_at(int index) const;
 400   oop   oop_at_phantom(int index) const; // phantom reference
 401   oop*  oop_addr_at(int index) const {  // for GC
 402     // relocation indexes are biased by 1 (because 0 is reserved)
 403     assert(index > 0 && index <= oops_count(), "must be a valid non-zero index");
 404     assert(!_oops_are_stale, "oops are stale");
 405     return &oops_begin()[index - 1];
 406   }
 407 
 408   // Support for meta data in scopes and relocs:
 409   // Note: index 0 is reserved for null.
 410   Metadata*     metadata_at(int index) const      { return index == 0 ? NULL: *metadata_addr_at(index); }
 411   Metadata**  metadata_addr_at(int index) const {  // for GC
 412     // relocation indexes are biased by 1 (because 0 is reserved)
 413     assert(index > 0 && index <= metadata_count(), "must be a valid non-zero index");
 414     return &metadata_begin()[index - 1];
 415   }
 416 
 417   void copy_values(GrowableArray<jobject>* oops);
 418   void copy_values(GrowableArray<Metadata*>* metadata);
 419 
 420   // Relocation support
 421 private:
 422   void fix_oop_relocations(address begin, address end, bool initialize_immediates);
 423   inline void initialize_immediate_oop(oop* dest, jobject handle);
 424 
 425 public:
 426   void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
 427   void fix_oop_relocations()                           { fix_oop_relocations(NULL, NULL, false); }
 428 
 429   // Sweeper support
 430   long  stack_traversal_mark()                    { return _stack_traversal_mark; }
 431   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }
 432 
 433   // On-stack replacement support
 434   int   osr_entry_bci() const                     { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
 435   address  osr_entry() const                      { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
 436   void  invalidate_osr_method();
 437   nmethod* osr_link() const                       { return _osr_link; }
 438   void     set_osr_link(nmethod *n)               { _osr_link = n; }
 439 
 440   // Verify calls to dead methods have been cleaned.
 441   void verify_clean_inline_caches();
 442 
 443   // unlink and deallocate this nmethod
 444   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
 445   // expected to use any other private methods/data in this class.
 446 
 447  protected:
 448   void flush();
 449 
 450  public:
 451   // When true is returned, it is unsafe to remove this nmethod even if
 452   // it is a zombie, since the VM or the ServiceThread might still be
 453   // using it.
 454   bool is_locked_by_vm() const                    { return _lock_count >0; }
 455 
 456   // See comment at definition of _last_seen_on_stack
 457   void mark_as_seen_on_stack();
 458   bool can_convert_to_zombie();
 459 
 460   // Evolution support. We make old (discarded) compiled methods point to new Method*s.
 461   void set_method(Method* method) { _method = method; }
 462 
 463 #if INCLUDE_JVMCI
 464   // Gets the JVMCI name of this nmethod.
 465   const char* jvmci_name();
 466 
 467   // Records the pending failed speculation in the
 468   // JVMCI speculation log associated with this nmethod.
 469   void update_speculation(JavaThread* thread);
 470 
 471   // Gets the data specific to a JVMCI compiled method.
 472   // This returns a non-NULL value iff this nmethod was
 473   // compiled by the JVMCI compiler.
 474   JVMCINMethodData* jvmci_nmethod_data() const {
 475     return jvmci_data_size() == 0 ? NULL : (JVMCINMethodData*) jvmci_data_begin();
 476   }
 477 #endif
 478 
 479  public:
 480   void oops_do(OopClosure* f) { oops_do(f, false); }
 481   void oops_do(OopClosure* f, bool allow_dead);
 482 
 483   bool test_set_oops_do_mark();
 484   static void oops_do_marking_prologue();
 485   static void oops_do_marking_epilogue();
 486   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
 487   bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
 488 
 489  private:
 490   ScopeDesc* scope_desc_in(address begin, address end);
 491 
 492   address* orig_pc_addr(const frame* fr);
 493 
 494  public:
 495   // copying of debugging information
 496   void copy_scopes_pcs(PcDesc* pcs, int count);
 497   void copy_scopes_data(address buffer, int size);
 498 
 499   // Accessor/mutator for the original pc of a frame before a frame was deopted.
 500   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }
 501   void    set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }
 502 
 503   // jvmti support:
 504   void post_compiled_method_load_event();
 505   jmethodID get_and_cache_jmethod_id();
 506 
 507   // verify operations
 508   void verify();
 509   void verify_scopes();
 510   void verify_interrupt_point(address interrupt_point);
 511 
 512   // Disassemble this nmethod with additional debug information, e.g. information about blocks.
 513   void decode2(outputStream* st) const;
 514   void print_constant_pool(outputStream* st);
 515 
 516   // Avoid hiding of parent's 'decode(outputStream*)' method.
 517   void decode(outputStream* st) const { decode2(st); } // just delegate here.
 518 
 519   // printing support
 520   void print()                          const;
 521   void print(outputStream* st)          const;
 522   void print_code();
 523 
 524 #if defined(SUPPORT_DATA_STRUCTS)
 525   // print output in opt build for disassembler library
 526   void print_relocations()                        PRODUCT_RETURN;
 527   void print_pcs() { print_pcs_on(tty); }
 528   void print_pcs_on(outputStream* st);
 529   void print_scopes() { print_scopes_on(tty); }
 530   void print_scopes_on(outputStream* st)          PRODUCT_RETURN;
 531   void print_value_on(outputStream* st) const;
 532   void print_handler_table();
 533   void print_nul_chk_table();
 534   void print_recorded_oops();
 535   void print_recorded_metadata();
 536 
 537   void print_oops(outputStream* st);     // oops from the underlying CodeBlob.
 538   void print_metadata(outputStream* st); // metadata in metadata pool.
 539 #else
 540   // void print_pcs()                             PRODUCT_RETURN;
 541   void print_pcs()                                { return; }
 542 #endif
 543 
 544   void print_calls(outputStream* st)              PRODUCT_RETURN;
 545   static void print_statistics()                  PRODUCT_RETURN;
 546 
 547   void maybe_print_nmethod(DirectiveSet* directive);
 548   void print_nmethod(bool print_code);
 549 
 550   // need to re-define this from CodeBlob else the overload hides it
 551   virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
 552   void print_on(outputStream* st, const char* msg) const;
 553 
 554   // Logging
 555   void log_identity(xmlStream* log) const;
 556   void log_new_nmethod() const;
 557   void log_state_change() const;
 558 
 559   // Prints block-level comments, including nmethod specific block labels:
 560   virtual void print_block_comment(outputStream* stream, address block_begin) const {
 561 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
 562     print_nmethod_labels(stream, block_begin);
 563     CodeBlob::print_block_comment(stream, block_begin);
 564 #endif
 565   }
 566   bool has_block_comment(address block_begin) {
 567     return CodeBlob::has_block_comment(block_begin);
 568   }
 569   void print_nmethod_labels(outputStream* stream, address block_begin, bool print_section_labels=true) const;
 570   const char* nmethod_section_label(address pos) const;
 571 
 572   // returns whether this nmethod has code comments.
 573   bool has_code_comment(address begin, address end);
 574   // Prints a comment for one native instruction (reloc info, pc desc)
 575   void print_code_comment_on(outputStream* st, int column, address begin, address end);
 576 
 577   // Compiler task identification.  Note that all OSR methods
 578   // are numbered in an independent sequence if CICountOSR is true,
 579   // and native method wrappers are also numbered independently if
 580   // CICountNative is true.
 581   virtual int compile_id() const { return _compile_id; }
 582   const char* compile_kind() const;
 583 
 584   // tells if any of this method's dependencies have been invalidated
 585   // (this is expensive!)
 586   static void check_all_dependencies(DepChange& changes);
 587 
 588   // tells if this compiled method is dependent on the given changes,
 589   // and the changes have invalidated it
 590   bool check_dependency_on(DepChange& changes);
 591 
 592   // Fast breakpoint support. Tells if this compiled method is
 593   // dependent on the given method. Returns true if this nmethod
 594   // corresponds to the given method as well.
 595   virtual bool is_dependent_on_method(Method* dependee);
 596 
 597   // is it ok to patch at address?
 598   bool is_patchable_at(address instr_address);
 599 
 600   // UseBiasedLocking support
 601   ByteSize native_receiver_sp_offset() {
 602     return _native_receiver_sp_offset;
 603   }
 604   ByteSize native_basic_lock_sp_offset() {
 605     return _native_basic_lock_sp_offset;
 606   }
 607 
 608   // support for code generation
 609   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }
 610   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }
 611   static int state_offset()                       { return offset_of(nmethod, _state); }
 612 
 613   virtual void metadata_do(MetadataClosure* f);
 614 
 615   NativeCallWrapper* call_wrapper_at(address call) const;
 616   NativeCallWrapper* call_wrapper_before(address return_pc) const;
 617   address call_instruction_address(address pc) const;
 618 
 619   virtual CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) const;
 620   virtual CompiledStaticCall* compiledStaticCall_at(address addr) const;
 621   virtual CompiledStaticCall* compiledStaticCall_before(address addr) const;
 622 };
 623 
 624 // Locks an nmethod so its code will not get removed and it will not
 625 // be made into a zombie, even if it is a not_entrant method. After the
 626 // nmethod becomes a zombie, if CompiledMethodUnload event processing
 627 // needs to be done, then lock_nmethod() is used directly to keep the
 628 // generated code from being reused too early.
 629 class nmethodLocker : public StackObj {
 630   CompiledMethod* _nm;
 631 
 632  public:
 633 
 634   // note: nm can be NULL
 635   // Only JvmtiDeferredEvent::compiled_method_unload_event()
 636   // should pass zombie_ok == true.
 637   static void lock_nmethod(CompiledMethod* nm, bool zombie_ok = false);
 638   static void unlock_nmethod(CompiledMethod* nm); // (ditto)
 639 
 640   nmethodLocker(address pc); // derive nm from pc
 641   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
 642   nmethodLocker(CompiledMethod *nm) {
 643     _nm = nm;
 644     lock(_nm);
 645   }
 646 
 647   static void lock(CompiledMethod* method) {
 648     if (method == NULL) return;
 649     lock_nmethod(method);
 650   }
 651 
 652   static void unlock(CompiledMethod* method) {
 653     if (method == NULL) return;
 654     unlock_nmethod(method);
 655   }
 656 
 657   nmethodLocker() { _nm = NULL; }
 658   ~nmethodLocker() {
 659     unlock(_nm);
 660   }
 661 
 662   CompiledMethod* code() { return _nm; }
 663   void set_code(CompiledMethod* new_nm) {
 664     unlock(_nm);   // note:  This works even if _nm==new_nm.
 665     _nm = new_nm;
 666     lock(_nm);
 667   }
 668 };
 669 
 670 #endif // SHARE_CODE_NMETHOD_HPP