1 /*
   2  * Copyright (c) 1997, 2019, 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.
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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).
  14  *
  15  * You should have received a copy of the GNU General Public License version
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  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
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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   int _nr_oops;
 116  public:
 117   int nr_oops() const { return _nr_oops; }
 118   void verify_nr_oops();
 119   int count_oops();
 120  private:
 121 
 122   // protected by CodeCache_lock
 123   bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)
 124 
 125   // used by jvmti to track if an unload event has been posted for this nmethod.
 126   bool _unload_reported;
 127 
 128   // Protected by Patching_lock
 129   volatile signed char _state;               // {not_installed, in_use, not_entrant, zombie, unloaded}
 130 
 131 #ifdef ASSERT
 132   bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
 133 #endif
 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   // Local state used to keep track of whether unloading is happening or not
 162   volatile uint8_t _is_unloading_state;
 163 
 164   // These are used for compiled synchronized native methods to
 165   // locate the owner and stack slot for the BasicLock so that we can
 166   // properly revoke the bias of the owner if necessary. They are
 167   // needed because there is no debug information for compiled native
 168   // wrappers and the oop maps are insufficient to allow
 169   // frame::retrieve_receiver() to work. Currently they are expected
 170   // to be byte offsets from the Java stack pointer for maximum code
 171   // sharing between platforms. Note that currently biased locking
 172   // will never cause Class instances to be biased but this code
 173   // handles the static synchronized case as well.
 174   // JVMTI's GetLocalInstance() also uses these offsets to find the receiver
 175   // for non-static native wrapper frames.
 176   ByteSize _native_receiver_sp_offset;
 177   ByteSize _native_basic_lock_sp_offset;
 178 
 179   friend class nmethodLocker;
 180 
 181   // For native wrappers
 182   nmethod(Method* method,
 183           CompilerType type,
 184           int nmethod_size,
 185           int compile_id,
 186           CodeOffsets* offsets,
 187           CodeBuffer *code_buffer,
 188           int frame_size,
 189           ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */
 190           ByteSize basic_lock_sp_offset,       /* synchronized natives only */
 191           OopMapSet* oop_maps);
 192 
 193   // Creation support
 194   nmethod(Method* method,
 195           CompilerType type,
 196           int nmethod_size,
 197           int compile_id,
 198           int entry_bci,
 199           CodeOffsets* offsets,
 200           int orig_pc_offset,
 201           DebugInformationRecorder *recorder,
 202           Dependencies* dependencies,
 203           CodeBuffer *code_buffer,
 204           int frame_size,
 205           OopMapSet* oop_maps,
 206           ExceptionHandlerTable* handler_table,
 207           ImplicitExceptionTable* nul_chk_table,
 208           AbstractCompiler* compiler,
 209           int comp_level
 210 #if INCLUDE_JVMCI
 211           , char* speculations,
 212           int speculations_len,
 213           int jvmci_data_size
 214 #endif
 215           );
 216 
 217   // helper methods
 218   void* operator new(size_t size, int nmethod_size, int comp_level) throw();
 219 
 220   const char* reloc_string_for(u_char* begin, u_char* end);
 221 
 222   bool try_transition(int new_state);
 223 
 224   // Returns true if this thread changed the state of the nmethod or
 225   // false if another thread performed the transition.
 226   bool make_not_entrant_or_zombie(int state);
 227   bool make_entrant() { Unimplemented(); return false; }
 228   void inc_decompile_count();
 229 
 230   // Inform external interfaces that a compiled method has been unloaded
 231   void post_compiled_method_unload();
 232 
 233   // Initailize fields to their default values
 234   void init_defaults();
 235 
 236   // Offsets
 237   int content_offset() const                  { return content_begin() - header_begin(); }
 238   int data_offset() const                     { return _data_offset; }
 239 
 240   address header_end() const                  { return (address)    header_begin() + header_size(); }
 241 
 242  public:
 243   // create nmethod with entry_bci
 244   static nmethod* new_nmethod(const methodHandle& method,
 245                               int compile_id,
 246                               int entry_bci,
 247                               CodeOffsets* offsets,
 248                               int orig_pc_offset,
 249                               DebugInformationRecorder* recorder,
 250                               Dependencies* dependencies,
 251                               CodeBuffer *code_buffer,
 252                               int frame_size,
 253                               OopMapSet* oop_maps,
 254                               ExceptionHandlerTable* handler_table,
 255                               ImplicitExceptionTable* nul_chk_table,
 256                               AbstractCompiler* compiler,
 257                               int comp_level
 258 #if INCLUDE_JVMCI
 259                               , char* speculations = NULL,
 260                               int speculations_len = 0,
 261                               int nmethod_mirror_index = -1,
 262                               const char* nmethod_mirror_name = NULL,
 263                               FailedSpeculation** failed_speculations = NULL
 264 #endif
 265   );
 266 
 267   // Only used for unit tests.
 268   nmethod()
 269     : CompiledMethod(),
 270       _is_unloading_state(0),
 271       _native_receiver_sp_offset(in_ByteSize(-1)),
 272       _native_basic_lock_sp_offset(in_ByteSize(-1)) {}
 273 
 274 
 275   static nmethod* new_native_nmethod(const methodHandle& method,
 276                                      int compile_id,
 277                                      CodeBuffer *code_buffer,
 278                                      int vep_offset,
 279                                      int frame_complete,
 280                                      int frame_size,
 281                                      ByteSize receiver_sp_offset,
 282                                      ByteSize basic_lock_sp_offset,
 283                                      OopMapSet* oop_maps);
 284 
 285   // type info
 286   bool is_nmethod() const                         { return true; }
 287   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }
 288 
 289   // boundaries for different parts
 290   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }
 291   address consts_end            () const          { return           code_begin()                           ; }
 292   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }
 293   address stub_end              () const          { return           header_begin() + _oops_offset          ; }
 294   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }
 295   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
 296   oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }
 297   oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }
 298 
 299   Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }
 300   Metadata** metadata_end     () const            { return (Metadata**)  _scopes_data_begin; }
 301 
 302   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }
 303   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }
 304   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
 305   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }
 306   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }
 307   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }
 308   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }
 309   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }
 310 #if INCLUDE_JVMCI
 311   address nul_chk_table_end     () const          { return           header_begin() + _speculations_offset  ; }
 312   address speculations_begin    () const          { return           header_begin() + _speculations_offset  ; }
 313   address speculations_end      () const          { return           header_begin() + _jvmci_data_offset   ; }
 314   address jvmci_data_begin      () const          { return           header_begin() + _jvmci_data_offset    ; }
 315   address jvmci_data_end        () const          { return           header_begin() + _nmethod_end_offset   ; }
 316 #else
 317   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }
 318 #endif
 319 
 320   // Sizes
 321   int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }
 322   int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }
 323   int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }
 324 #if INCLUDE_JVMCI
 325   int speculations_size () const                  { return            speculations_end () -            speculations_begin (); }
 326   int jvmci_data_size   () const                  { return            jvmci_data_end   () -            jvmci_data_begin   (); }
 327 #endif
 328 
 329   int     oops_count() const { assert(oops_size() % oopSize == 0, "");  return (oops_size() / oopSize) + 1; }
 330   int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }
 331 
 332   int total_size        () const;
 333 
 334   void dec_hotness_counter()        { _hotness_counter--; }
 335   void set_hotness_counter(int val) { _hotness_counter = val; }
 336   int  hotness_counter() const      { return _hotness_counter; }
 337 
 338   // Containment
 339   bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }
 340   bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }
 341   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }
 342   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }
 343 
 344   // entry points
 345   address entry_point() const                     { return _entry_point;             } // normal entry point
 346   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 347 
 348   // flag accessing and manipulation
 349   bool  is_not_installed() const                  { return _state == not_installed; }
 350   bool  is_in_use() const                         { return _state <= in_use; }
 351   bool  is_alive() const                          { return _state < unloaded; }
 352   bool  is_not_entrant() const                    { return _state == not_entrant; }
 353   bool  is_zombie() const                         { return _state == zombie; }
 354   bool  is_unloaded() const                       { return _state == unloaded; }
 355 
 356   void clear_unloading_state();
 357   virtual bool is_unloading();
 358   virtual void do_unloading(bool unloading_occurred);
 359 
 360 #if INCLUDE_RTM_OPT
 361   // rtm state accessing and manipulating
 362   RTMState  rtm_state() const                     { return _rtm_state; }
 363   void set_rtm_state(RTMState state)              { _rtm_state = state; }
 364 #endif
 365 
 366   void make_in_use()                              { _state = in_use; }
 367   // Make the nmethod non entrant. The nmethod will continue to be
 368   // alive.  It is used when an uncommon trap happens.  Returns true
 369   // if this thread changed the state of the nmethod or false if
 370   // another thread performed the transition.
 371   bool  make_not_entrant() {
 372     assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
 373     return make_not_entrant_or_zombie(not_entrant);
 374   }
 375   bool  make_not_used()    { return make_not_entrant(); }
 376   bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }
 377 
 378   // used by jvmti to track if the unload event has been reported
 379   bool  unload_reported()                         { return _unload_reported; }
 380   void  set_unload_reported()                     { _unload_reported = true; }
 381 
 382   int get_state() const {
 383     return _state;
 384   }
 385 
 386   void  make_unloaded();
 387 
 388   bool has_dependencies()                         { return dependencies_size() != 0; }
 389   void print_dependencies()                       PRODUCT_RETURN;
 390   void flush_dependencies(bool delete_immediately);
 391   bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }
 392   void set_has_flushed_dependencies()             {
 393     assert(!has_flushed_dependencies(), "should only happen once");
 394     _has_flushed_dependencies = 1;
 395   }
 396 
 397   int   comp_level() const                        { return _comp_level; }
 398 
 399   void unlink_from_method(bool acquire_lock);
 400 
 401   // Support for oops in scopes and relocs:
 402   // Note: index 0 is reserved for null.
 403   oop   oop_at(int index) const;
 404   oop   oop_at_phantom(int index) const; // phantom reference
 405   oop*  oop_addr_at(int index) const {  // for GC
 406     // relocation indexes are biased by 1 (because 0 is reserved)
 407     assert(index > 0 && index <= oops_count(), "must be a valid non-zero index");
 408     assert(!_oops_are_stale, "oops are stale");
 409     return &oops_begin()[index - 1];
 410   }
 411 
 412   // Support for meta data in scopes and relocs:
 413   // Note: index 0 is reserved for null.
 414   Metadata*     metadata_at(int index) const      { return index == 0 ? NULL: *metadata_addr_at(index); }
 415   Metadata**  metadata_addr_at(int index) const {  // for GC
 416     // relocation indexes are biased by 1 (because 0 is reserved)
 417     assert(index > 0 && index <= metadata_count(), "must be a valid non-zero index");
 418     return &metadata_begin()[index - 1];
 419   }
 420 
 421   void copy_values(GrowableArray<jobject>* oops);
 422   void copy_values(GrowableArray<Metadata*>* metadata);
 423 
 424   // Relocation support
 425 private:
 426   void fix_oop_relocations(address begin, address end, bool initialize_immediates);
 427   inline void initialize_immediate_oop(oop* dest, jobject handle);
 428 
 429 public:
 430   void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
 431   void fix_oop_relocations()                           { fix_oop_relocations(NULL, NULL, false); }
 432 
 433   // Sweeper support
 434   long  stack_traversal_mark()                    { return _stack_traversal_mark; }
 435   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }
 436 
 437   // On-stack replacement support
 438   int   osr_entry_bci() const                     { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
 439   address  osr_entry() const                      { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
 440   void  invalidate_osr_method();
 441   nmethod* osr_link() const                       { return _osr_link; }
 442   void     set_osr_link(nmethod *n)               { _osr_link = n; }
 443 
 444   void set_immediate_oops_patched(int nr)         { _nr_oops += nr; }
 445 
 446   // Verify calls to dead methods have been cleaned.
 447   void verify_clean_inline_caches();
 448 
 449   // unlink and deallocate this nmethod
 450   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
 451   // expected to use any other private methods/data in this class.
 452 
 453  protected:
 454   void flush();
 455 
 456  public:
 457   // When true is returned, it is unsafe to remove this nmethod even if
 458   // it is a zombie, since the VM or the ServiceThread might still be
 459   // using it.
 460   bool is_locked_by_vm() const                    { return _lock_count >0; }
 461 
 462   // See comment at definition of _last_seen_on_stack
 463   void mark_as_seen_on_stack();
 464   bool can_convert_to_zombie();
 465 
 466   // Evolution support. We make old (discarded) compiled methods point to new Method*s.
 467   void set_method(Method* method) { _method = method; }
 468 
 469 #if INCLUDE_JVMCI
 470   // Gets the JVMCI name of this nmethod.
 471   const char* jvmci_name();
 472 
 473   // Records the pending failed speculation in the
 474   // JVMCI speculation log associated with this nmethod.
 475   void update_speculation(JavaThread* thread);
 476 
 477   // Gets the data specific to a JVMCI compiled method.
 478   // This returns a non-NULL value iff this nmethod was
 479   // compiled by the JVMCI compiler.
 480   JVMCINMethodData* jvmci_nmethod_data() const {
 481     return jvmci_data_size() == 0 ? NULL : (JVMCINMethodData*) jvmci_data_begin();
 482   }
 483 #endif
 484 
 485  public:
 486   void oops_do_keepalive(OopClosure* f, bool keepalive) { oops_do(f, false, false, keepalive); }
 487   void oops_do(OopClosure* f) { oops_do(f, false, false); }
 488   void oops_do(OopClosure* f, bool allow_dead, bool allow_null = false, bool shadow_is_strong = false);
 489 
 490   bool test_set_oops_do_mark();
 491   static void oops_do_marking_prologue();
 492   static void oops_do_marking_epilogue();
 493   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
 494   bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
 495 
 496  private:
 497   ScopeDesc* scope_desc_in(address begin, address end);
 498 
 499  public:
 500   // copying of debugging information
 501   void copy_scopes_pcs(PcDesc* pcs, int count);
 502   void copy_scopes_data(address buffer, int size);
 503 
 504   int orig_pc_offset() { return _orig_pc_offset; }
 505 
 506   // jvmti support:
 507   void post_compiled_method_load_event();
 508   jmethodID get_and_cache_jmethod_id();
 509 
 510   // verify operations
 511   void verify();
 512   void verify_scopes();
 513   void verify_interrupt_point(address interrupt_point);
 514 
 515   // Disassemble this nmethod with additional debug information, e.g. information about blocks.
 516   void decode2(outputStream* st) const;
 517   void print_constant_pool(outputStream* st);
 518 
 519   // Avoid hiding of parent's 'decode(outputStream*)' method.
 520   void decode(outputStream* st) const { decode2(st); } // just delegate here.
 521 
 522   // printing support
 523   void print()                          const;
 524   void print(outputStream* st)          const;
 525   void print_code();
 526 
 527 #if defined(SUPPORT_DATA_STRUCTS)
 528   // print output in opt build for disassembler library
 529   void print_relocations()                        PRODUCT_RETURN;
 530   void print_pcs() { print_pcs_on(tty); }
 531   void print_pcs_on(outputStream* st);
 532   void print_scopes() { print_scopes_on(tty); }
 533   void print_scopes_on(outputStream* st)          PRODUCT_RETURN;
 534   void print_value_on(outputStream* st) const;
 535   void print_handler_table();
 536   void print_nul_chk_table();
 537   void print_recorded_oops();
 538   void print_recorded_metadata();
 539 
 540   void print_oops(outputStream* st);     // oops from the underlying CodeBlob.
 541   void print_metadata(outputStream* st); // metadata in metadata pool.
 542 #else
 543   // void print_pcs()                             PRODUCT_RETURN;
 544   void print_pcs()                                { return; }
 545 #endif
 546 
 547   void print_calls(outputStream* st)              PRODUCT_RETURN;
 548   static void print_statistics()                  PRODUCT_RETURN;
 549 
 550   void maybe_print_nmethod(DirectiveSet* directive);
 551   void print_nmethod(bool print_code);
 552 
 553   // need to re-define this from CodeBlob else the overload hides it
 554   virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
 555   void print_on(outputStream* st, const char* msg) const;
 556 
 557   // Logging
 558   void log_identity(xmlStream* log) const;
 559   void log_new_nmethod() const;
 560   void log_state_change() const;
 561 
 562   // Prints block-level comments, including nmethod specific block labels:
 563   virtual void print_block_comment(outputStream* stream, address block_begin) const {
 564 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
 565     print_nmethod_labels(stream, block_begin);
 566     CodeBlob::print_block_comment(stream, block_begin);
 567 #endif
 568   }
 569   bool has_block_comment(address block_begin) {
 570     return CodeBlob::has_block_comment(block_begin);
 571   }
 572   void print_nmethod_labels(outputStream* stream, address block_begin, bool print_section_labels=true) const;
 573   const char* nmethod_section_label(address pos) const;
 574 
 575   // returns whether this nmethod has code comments.
 576   bool has_code_comment(address begin, address end);
 577   // Prints a comment for one native instruction (reloc info, pc desc)
 578   void print_code_comment_on(outputStream* st, int column, address begin, address end);
 579 
 580   // Compiler task identification.  Note that all OSR methods
 581   // are numbered in an independent sequence if CICountOSR is true,
 582   // and native method wrappers are also numbered independently if
 583   // CICountNative is true.
 584   virtual int compile_id() const { return _compile_id; }
 585   const char* compile_kind() const;
 586 
 587   // tells if any of this method's dependencies have been invalidated
 588   // (this is expensive!)
 589   static void check_all_dependencies(DepChange& changes);
 590 
 591   // tells if this compiled method is dependent on the given changes,
 592   // and the changes have invalidated it
 593   bool check_dependency_on(DepChange& changes);
 594 
 595   // Fast breakpoint support. Tells if this compiled method is
 596   // dependent on the given method. Returns true if this nmethod
 597   // corresponds to the given method as well.
 598   virtual bool is_dependent_on_method(Method* dependee);
 599 
 600   // is it ok to patch at address?
 601   bool is_patchable_at(address instr_address);
 602 
 603   // UseBiasedLocking support
 604   ByteSize native_receiver_sp_offset() {
 605     return _native_receiver_sp_offset;
 606   }
 607   ByteSize native_basic_lock_sp_offset() {
 608     return _native_basic_lock_sp_offset;
 609   }
 610 
 611   // support for code generation
 612   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }
 613   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }
 614   static int state_offset()                       { return offset_of(nmethod, _state); }
 615 
 616   virtual void metadata_do(MetadataClosure* f);
 617 
 618   NativeCallWrapper* call_wrapper_at(address call) const;
 619   NativeCallWrapper* call_wrapper_before(address return_pc) const;
 620   address call_instruction_address(address pc) const;
 621 
 622   virtual CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) const;
 623   virtual CompiledStaticCall* compiledStaticCall_at(address addr) const;
 624   virtual CompiledStaticCall* compiledStaticCall_before(address addr) const;
 625 };
 626 
 627 // Locks an nmethod so its code will not get removed and it will not
 628 // be made into a zombie, even if it is a not_entrant method. After the
 629 // nmethod becomes a zombie, if CompiledMethodUnload event processing
 630 // needs to be done, then lock_nmethod() is used directly to keep the
 631 // generated code from being reused too early.
 632 class nmethodLocker : public StackObj {
 633   CompiledMethod* _nm;
 634 
 635  public:
 636 
 637   // note: nm can be NULL
 638   // Only JvmtiDeferredEvent::compiled_method_unload_event()
 639   // should pass zombie_ok == true.
 640   static void lock_nmethod(CompiledMethod* nm, bool zombie_ok = false);
 641   static void unlock_nmethod(CompiledMethod* nm); // (ditto)
 642 
 643   nmethodLocker(address pc); // derive nm from pc
 644   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
 645   nmethodLocker(CompiledMethod *nm) {
 646     _nm = nm;
 647     lock(_nm);
 648   }
 649 
 650   static void lock(CompiledMethod* method) {
 651     if (method == NULL) return;
 652     lock_nmethod(method);
 653   }
 654 
 655   static void unlock(CompiledMethod* method) {
 656     if (method == NULL) return;
 657     unlock_nmethod(method);
 658   }
 659 
 660   nmethodLocker() { _nm = NULL; }
 661   ~nmethodLocker() {
 662     unlock(_nm);
 663   }
 664 
 665   CompiledMethod* code() { return _nm; }
 666   void set_code(CompiledMethod* new_nm) {
 667     unlock(_nm);   // note:  This works even if _nm==new_nm.
 668     _nm = new_nm;
 669     lock(_nm);
 670   }
 671 };
 672 
 673 #endif // SHARE_CODE_NMETHOD_HPP