1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CODE_NMETHOD_HPP
  26 #define SHARE_VM_CODE_NMETHOD_HPP
  27 
  28 #include "code/codeBlob.hpp"
  29 #include "code/pcDesc.hpp"
  30 #include "oops/metadata.hpp"
  31 
  32 // This class is used internally by nmethods, to cache
  33 // exception/pc/handler information.
  34 
  35 class ExceptionCache : public CHeapObj<mtCode> {
  36   friend class VMStructs;
  37  private:
  38   enum { cache_size = 16 };
  39   Klass*   _exception_type;
  40   address  _pc[cache_size];
  41   address  _handler[cache_size];
  42   int      _count;
  43   ExceptionCache* _next;
  44 
  45   address pc_at(int index)                     { assert(index >= 0 && index < count(),""); return _pc[index]; }
  46   void    set_pc_at(int index, address a)      { assert(index >= 0 && index < cache_size,""); _pc[index] = a; }
  47   address handler_at(int index)                { assert(index >= 0 && index < count(),""); return _handler[index]; }
  48   void    set_handler_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _handler[index] = a; }
  49   int     count()                              { return _count; }
  50   void    increment_count()                    { _count++; }
  51 
  52  public:
  53 
  54   ExceptionCache(Handle exception, address pc, address handler);
  55 
  56   Klass*    exception_type()                { return _exception_type; }
  57   ExceptionCache* next()                    { return _next; }
  58   void      set_next(ExceptionCache *ec)    { _next = ec; }
  59 
  60   address match(Handle exception, address pc);
  61   bool    match_exception_with_space(Handle exception) ;
  62   address test_address(address addr);
  63   bool    add_address_and_handler(address addr, address handler) ;
  64 };
  65 
  66 
  67 // cache pc descs found in earlier inquiries
  68 class PcDescCache VALUE_OBJ_CLASS_SPEC {
  69   friend class VMStructs;
  70  private:
  71   enum { cache_size = 4 };
  72   // The array elements MUST be volatile! Several threads may modify
  73   // and read from the cache concurrently. find_pc_desc_internal has
  74   // returned wrong results. C++ compiler (namely xlC12) may duplicate
  75   // C++ field accesses if the elements are not volatile.
  76   typedef PcDesc* PcDescPtr;
  77   volatile PcDescPtr _pc_descs[cache_size]; // last cache_size pc_descs found
  78  public:
  79   PcDescCache() { debug_only(_pc_descs[0] = NULL); }
  80   void    reset_to(PcDesc* initial_pc_desc);
  81   PcDesc* find_pc_desc(int pc_offset, bool approximate);
  82   void    add_pc_desc(PcDesc* pc_desc);
  83   PcDesc* last_pc_desc() { return _pc_descs[0]; }
  84 };
  85 
  86 
  87 // nmethods (native methods) are the compiled code versions of Java methods.
  88 //
  89 // An nmethod contains:
  90 //  - header                 (the nmethod structure)
  91 //  [Relocation]
  92 //  - relocation information
  93 //  - constant part          (doubles, longs and floats used in nmethod)
  94 //  - oop table
  95 //  [Code]
  96 //  - code body
  97 //  - exception handler
  98 //  - stub code
  99 //  [Debugging information]
 100 //  - oop array
 101 //  - data array
 102 //  - pcs
 103 //  [Exception handler table]
 104 //  - handler entry point array
 105 //  [Implicit Null Pointer exception table]
 106 //  - implicit null table array
 107 
 108 class Dependencies;
 109 class ExceptionHandlerTable;
 110 class ImplicitExceptionTable;
 111 class AbstractCompiler;
 112 class xmlStream;
 113 
 114 class nmethod : public CodeBlob {
 115   friend class VMStructs;
 116   friend class NMethodSweeper;
 117   friend class CodeCache;  // scavengable oops
 118  private:
 119 
 120   // GC support to help figure out if an nmethod has been
 121   // cleaned/unloaded by the current GC.
 122   static unsigned char _global_unloading_clock;
 123 
 124   // Shared fields for all nmethod's
 125   Method*   _method;
 126   int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method
 127   jmethodID _jmethod_id;       // Cache of method()->jmethod_id()
 128 






 129   // To support simple linked-list chaining of nmethods:
 130   nmethod*  _osr_link;         // from InstanceKlass::osr_nmethods_head
 131 
 132   union {
 133     // Used by G1 to chain nmethods.
 134     nmethod* _unloading_next;
 135     // Used by non-G1 GCs to chain nmethods.
 136     nmethod* _scavenge_root_link; // from CodeCache::scavenge_root_nmethods
 137   };
 138 
 139   static nmethod* volatile _oops_do_mark_nmethods;
 140   nmethod*        volatile _oops_do_mark_link;
 141 
 142   AbstractCompiler* _compiler; // The compiler which compiled this nmethod
 143 
 144   // offsets for entry points
 145   address _entry_point;                      // entry point with class check
 146   address _verified_entry_point;             // entry point without class check
 147   address _osr_entry_point;                  // entry point for on stack replacement
 148 
 149   // Offsets for different nmethod parts
 150   int _exception_offset;
 151   // All deoptee's will resume execution at this location described by
 152   // this offset.
 153   int _deoptimize_offset;
 154   // All deoptee's at a MethodHandle call site will resume execution
 155   // at this location described by this offset.
 156   int _deoptimize_mh_offset;
 157   // Offset of the unwind handler if it exists
 158   int _unwind_handler_offset;
 159 
 160   int _consts_offset;
 161   int _stub_offset;
 162   int _oops_offset;                       // offset to where embedded oop table begins (inside data)
 163   int _metadata_offset;                   // embedded meta data table
 164   int _scopes_data_offset;
 165   int _scopes_pcs_offset;
 166   int _dependencies_offset;
 167   int _handler_table_offset;
 168   int _nul_chk_table_offset;
 169   int _nmethod_end_offset;
 170 
 171   // location in frame (offset for sp) that deopt can store the original
 172   // pc during a deopt.
 173   int _orig_pc_offset;
 174 
 175   int _compile_id;                           // which compilation made this nmethod
 176   int _comp_level;                           // compilation level
 177 
 178   // protected by CodeCache_lock
 179   bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)
 180 
 181   bool _marked_for_reclamation;              // Used by NMethodSweeper (set only by sweeper)
 182   bool _marked_for_deoptimization;           // Used for stack deoptimization
 183 
 184   // used by jvmti to track if an unload event has been posted for this nmethod.
 185   bool _unload_reported;
 186 
 187   // set during construction
 188   unsigned int _has_unsafe_access:1;         // May fault due to unsafe access.
 189   unsigned int _has_method_handle_invokes:1; // Has this method MethodHandle invokes?
 190   unsigned int _lazy_critical_native:1;      // Lazy JNI critical native
 191   unsigned int _has_wide_vectors:1;          // Preserve wide vectors at safepoints
 192 
 193   // Protected by Patching_lock
 194   volatile unsigned char _state;             // {alive, not_entrant, zombie, unloaded}
 195 
 196   volatile unsigned char _unloading_clock;   // Incremented after GC unloaded/cleaned the nmethod
 197 
 198 #ifdef ASSERT
 199   bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
 200 #endif
 201 
 202   jbyte _scavenge_root_state;
 203 
 204 #if INCLUDE_RTM_OPT
 205   // RTM state at compile time. Used during deoptimization to decide
 206   // whether to restart collecting RTM locking abort statistic again.
 207   RTMState _rtm_state;
 208 #endif
 209 
 210   // Nmethod Flushing lock. If non-zero, then the nmethod is not removed
 211   // and is not made into a zombie. However, once the nmethod is made into
 212   // a zombie, it will be locked one final time if CompiledMethodUnload
 213   // event processing needs to be done.
 214   volatile jint _lock_count;
 215 
 216   // not_entrant method removal. Each mark_sweep pass will update
 217   // this mark to current sweep invocation count if it is seen on the
 218   // stack.  An not_entrant method can be removed when there are no
 219   // more activations, i.e., when the _stack_traversal_mark is less than
 220   // current sweep traversal index.
 221   long _stack_traversal_mark;
 222 
 223   // The _hotness_counter indicates the hotness of a method. The higher
 224   // the value the hotter the method. The hotness counter of a nmethod is
 225   // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method
 226   // is active while stack scanning (mark_active_nmethods()). The hotness
 227   // counter is decreased (by 1) while sweeping.
 228   int _hotness_counter;
 229 
 230   ExceptionCache *_exception_cache;
 231   PcDescCache     _pc_desc_cache;
 232 
 233   // These are used for compiled synchronized native methods to
 234   // locate the owner and stack slot for the BasicLock so that we can
 235   // properly revoke the bias of the owner if necessary. They are
 236   // needed because there is no debug information for compiled native
 237   // wrappers and the oop maps are insufficient to allow
 238   // frame::retrieve_receiver() to work. Currently they are expected
 239   // to be byte offsets from the Java stack pointer for maximum code
 240   // sharing between platforms. Note that currently biased locking
 241   // will never cause Class instances to be biased but this code
 242   // handles the static synchronized case as well.
 243   // JVMTI's GetLocalInstance() also uses these offsets to find the receiver
 244   // for non-static native wrapper frames.
 245   ByteSize _native_receiver_sp_offset;
 246   ByteSize _native_basic_lock_sp_offset;
 247 
 248   friend class nmethodLocker;
 249 
 250   // For native wrappers
 251   nmethod(Method* method,
 252           int nmethod_size,
 253           int compile_id,
 254           CodeOffsets* offsets,
 255           CodeBuffer *code_buffer,
 256           int frame_size,
 257           ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */
 258           ByteSize basic_lock_sp_offset,       /* synchronized natives only */
 259           OopMapSet* oop_maps);
 260 
 261   // Creation support
 262   nmethod(Method* method,
 263           int nmethod_size,
 264           int compile_id,
 265           int entry_bci,
 266           CodeOffsets* offsets,
 267           int orig_pc_offset,
 268           DebugInformationRecorder *recorder,
 269           Dependencies* dependencies,
 270           CodeBuffer *code_buffer,
 271           int frame_size,
 272           OopMapSet* oop_maps,
 273           ExceptionHandlerTable* handler_table,
 274           ImplicitExceptionTable* nul_chk_table,
 275           AbstractCompiler* compiler,
 276           int comp_level);





 277 
 278   // helper methods
 279   void* operator new(size_t size, int nmethod_size, int comp_level) throw();
 280 
 281   const char* reloc_string_for(u_char* begin, u_char* end);
 282   // Returns true if this thread changed the state of the nmethod or
 283   // false if another thread performed the transition.
 284   bool make_not_entrant_or_zombie(unsigned int state);
 285   void inc_decompile_count();
 286 
 287   // Used to manipulate the exception cache
 288   void add_exception_cache_entry(ExceptionCache* new_entry);
 289   ExceptionCache* exception_cache_entry_for_exception(Handle exception);
 290 
 291   // Inform external interfaces that a compiled method has been unloaded
 292   void post_compiled_method_unload();
 293 
 294   // Initailize fields to their default values
 295   void init_defaults();
 296 
 297  public:
 298   // create nmethod with entry_bci
 299   static nmethod* new_nmethod(methodHandle method,
 300                               int compile_id,
 301                               int entry_bci,
 302                               CodeOffsets* offsets,
 303                               int orig_pc_offset,
 304                               DebugInformationRecorder* recorder,
 305                               Dependencies* dependencies,
 306                               CodeBuffer *code_buffer,
 307                               int frame_size,
 308                               OopMapSet* oop_maps,
 309                               ExceptionHandlerTable* handler_table,
 310                               ImplicitExceptionTable* nul_chk_table,
 311                               AbstractCompiler* compiler,
 312                               int comp_level);





 313 
 314   static nmethod* new_native_nmethod(methodHandle method,
 315                                      int compile_id,
 316                                      CodeBuffer *code_buffer,
 317                                      int vep_offset,
 318                                      int frame_complete,
 319                                      int frame_size,
 320                                      ByteSize receiver_sp_offset,
 321                                      ByteSize basic_lock_sp_offset,
 322                                      OopMapSet* oop_maps);
 323 
 324   // accessors
 325   Method* method() const                          { return _method; }
 326   AbstractCompiler* compiler() const              { return _compiler; }
 327 
 328   // type info
 329   bool is_nmethod() const                         { return true; }
 330   bool is_java_method() const                     { return !method()->is_native(); }
 331   bool is_native_method() const                   { return method()->is_native(); }
 332   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }
 333 
 334   bool is_compiled_by_c1() const;

 335   bool is_compiled_by_c2() const;
 336   bool is_compiled_by_shark() const;
 337 
 338   // boundaries for different parts
 339   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }
 340   address consts_end            () const          { return           header_begin() +  code_offset()        ; }
 341   address insts_begin           () const          { return           header_begin() +  code_offset()        ; }
 342   address insts_end             () const          { return           header_begin() + _stub_offset          ; }
 343   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }
 344   address stub_end              () const          { return           header_begin() + _oops_offset          ; }
 345   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }
 346   address deopt_handler_begin   () const          { return           header_begin() + _deoptimize_offset    ; }
 347   address deopt_mh_handler_begin() const          { return           header_begin() + _deoptimize_mh_offset ; }
 348   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
 349   oop*    oops_begin            () const          { return (oop*)   (header_begin() + _oops_offset)         ; }
 350   oop*    oops_end              () const          { return (oop*)   (header_begin() + _metadata_offset)     ; }
 351 
 352   Metadata** metadata_begin   () const            { return (Metadata**)  (header_begin() + _metadata_offset)     ; }
 353   Metadata** metadata_end     () const            { return (Metadata**)  (header_begin() + _scopes_data_offset)  ; }
 354 
 355   address scopes_data_begin     () const          { return           header_begin() + _scopes_data_offset   ; }
 356   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }
 357   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }
 358   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
 359   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }
 360   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }
 361   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }
 362   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }
 363   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }
 364   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }
 365 
 366   // Sizes
 367   int consts_size       () const                  { return            consts_end       () -            consts_begin       (); }
 368   int insts_size        () const                  { return            insts_end        () -            insts_begin        (); }
 369   int stub_size         () const                  { return            stub_end         () -            stub_begin         (); }
 370   int oops_size         () const                  { return (address)  oops_end         () - (address)  oops_begin         (); }
 371   int metadata_size     () const                  { return (address)  metadata_end     () - (address)  metadata_begin     (); }
 372   int scopes_data_size  () const                  { return            scopes_data_end  () -            scopes_data_begin  (); }
 373   int scopes_pcs_size   () const                  { return (intptr_t) scopes_pcs_end   () - (intptr_t) scopes_pcs_begin   (); }
 374   int dependencies_size () const                  { return            dependencies_end () -            dependencies_begin (); }
 375   int handler_table_size() const                  { return            handler_table_end() -            handler_table_begin(); }
 376   int nul_chk_table_size() const                  { return            nul_chk_table_end() -            nul_chk_table_begin(); }
 377 
 378   int total_size        () const;
 379 
 380   void dec_hotness_counter()        { _hotness_counter--; }
 381   void set_hotness_counter(int val) { _hotness_counter = val; }
 382   int  hotness_counter() const      { return _hotness_counter; }
 383 
 384   // Containment
 385   bool consts_contains       (address addr) const { return consts_begin       () <= addr && addr < consts_end       (); }
 386   bool insts_contains        (address addr) const { return insts_begin        () <= addr && addr < insts_end        (); }
 387   bool stub_contains         (address addr) const { return stub_begin         () <= addr && addr < stub_end         (); }
 388   bool oops_contains         (oop*    addr) const { return oops_begin         () <= addr && addr < oops_end         (); }
 389   bool metadata_contains     (Metadata** addr) const   { return metadata_begin     () <= addr && addr < metadata_end     (); }
 390   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }
 391   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }
 392   bool handler_table_contains(address addr) const { return handler_table_begin() <= addr && addr < handler_table_end(); }
 393   bool nul_chk_table_contains(address addr) const { return nul_chk_table_begin() <= addr && addr < nul_chk_table_end(); }
 394 
 395   // entry points
 396   address entry_point() const                     { return _entry_point;             } // normal entry point
 397   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 398 
 399   enum { in_use       = 0,   // executable nmethod
 400          not_entrant  = 1,   // marked for deoptimization but activations may still exist,
 401                              // will be transformed to zombie when all activations are gone
 402          zombie       = 2,   // no activations exist, nmethod is ready for purge
 403          unloaded     = 3 }; // there should be no activations, should not be called,
 404                              // will be transformed to zombie immediately
 405 
 406   // flag accessing and manipulation
 407   bool  is_in_use() const                         { return _state == in_use; }
 408   bool  is_alive() const                          { return _state == in_use || _state == not_entrant; }
 409   bool  is_not_entrant() const                    { return _state == not_entrant; }
 410   bool  is_zombie() const                         { return _state == zombie; }
 411   bool  is_unloaded() const                       { return _state == unloaded;   }
 412 
 413 #if INCLUDE_RTM_OPT
 414   // rtm state accessing and manipulating
 415   RTMState  rtm_state() const                     { return _rtm_state; }
 416   void set_rtm_state(RTMState state)              { _rtm_state = state; }
 417 #endif
 418 
 419   // Make the nmethod non entrant. The nmethod will continue to be
 420   // alive.  It is used when an uncommon trap happens.  Returns true
 421   // if this thread changed the state of the nmethod or false if
 422   // another thread performed the transition.
 423   bool  make_not_entrant() {
 424     assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
 425     return make_not_entrant_or_zombie(not_entrant);
 426   }
 427   bool  make_zombie()      { return make_not_entrant_or_zombie(zombie); }
 428 
 429   // used by jvmti to track if the unload event has been reported
 430   bool  unload_reported()                         { return _unload_reported; }
 431   void  set_unload_reported()                     { _unload_reported = true; }
 432 
 433   void set_unloading_next(nmethod* next)          { _unloading_next = next; }
 434   nmethod* unloading_next()                       { return _unloading_next; }
 435 
 436   static unsigned char global_unloading_clock()   { return _global_unloading_clock; }
 437   static void increase_unloading_clock();
 438 
 439   void set_unloading_clock(unsigned char unloading_clock);
 440   unsigned char unloading_clock();
 441 
 442   bool  is_marked_for_deoptimization() const      { return _marked_for_deoptimization; }
 443   void  mark_for_deoptimization()                 { _marked_for_deoptimization = true; }
 444 
 445   void  make_unloaded(BoolObjectClosure* is_alive, oop cause);
 446 
 447   bool has_dependencies()                         { return dependencies_size() != 0; }
 448   void flush_dependencies(BoolObjectClosure* is_alive);
 449   bool has_flushed_dependencies()                 { return _has_flushed_dependencies; }
 450   void set_has_flushed_dependencies()             {
 451     assert(!has_flushed_dependencies(), "should only happen once");
 452     _has_flushed_dependencies = 1;
 453   }
 454 
 455   bool  is_marked_for_reclamation() const         { return _marked_for_reclamation; }
 456   void  mark_for_reclamation()                    { _marked_for_reclamation = 1; }
 457 
 458   bool  has_unsafe_access() const                 { return _has_unsafe_access; }
 459   void  set_has_unsafe_access(bool z)             { _has_unsafe_access = z; }
 460 
 461   bool  has_method_handle_invokes() const         { return _has_method_handle_invokes; }
 462   void  set_has_method_handle_invokes(bool z)     { _has_method_handle_invokes = z; }
 463 
 464   bool  is_lazy_critical_native() const           { return _lazy_critical_native; }
 465   void  set_lazy_critical_native(bool z)          { _lazy_critical_native = z; }
 466 
 467   bool  has_wide_vectors() const                  { return _has_wide_vectors; }
 468   void  set_has_wide_vectors(bool z)              { _has_wide_vectors = z; }
 469 
 470   int   comp_level() const                        { return _comp_level; }
 471 
 472   // Support for oops in scopes and relocs:
 473   // Note: index 0 is reserved for null.
 474   oop   oop_at(int index) const                   { return index == 0 ? (oop) NULL: *oop_addr_at(index); }
 475   oop*  oop_addr_at(int index) const {  // for GC
 476     // relocation indexes are biased by 1 (because 0 is reserved)
 477     assert(index > 0 && index <= oops_size(), "must be a valid non-zero index");
 478     assert(!_oops_are_stale, "oops are stale");
 479     return &oops_begin()[index - 1];
 480   }
 481 
 482   // Support for meta data in scopes and relocs:
 483   // Note: index 0 is reserved for null.
 484   Metadata*     metadata_at(int index) const      { return index == 0 ? NULL: *metadata_addr_at(index); }
 485   Metadata**  metadata_addr_at(int index) const {  // for GC
 486     // relocation indexes are biased by 1 (because 0 is reserved)
 487     assert(index > 0 && index <= metadata_size(), "must be a valid non-zero index");
 488     return &metadata_begin()[index - 1];
 489   }
 490 
 491   void copy_values(GrowableArray<jobject>* oops);
 492   void copy_values(GrowableArray<Metadata*>* metadata);
 493 
 494   // Relocation support
 495 private:
 496   void fix_oop_relocations(address begin, address end, bool initialize_immediates);
 497   inline void initialize_immediate_oop(oop* dest, jobject handle);
 498 
 499 public:
 500   void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
 501   void fix_oop_relocations()                           { fix_oop_relocations(NULL, NULL, false); }
 502   void verify_oop_relocations();
 503 
 504   bool is_at_poll_return(address pc);
 505   bool is_at_poll_or_poll_return(address pc);
 506 
 507   // Scavengable oop support
 508   bool  on_scavenge_root_list() const                  { return (_scavenge_root_state & 1) != 0; }
 509  protected:
 510   enum { sl_on_list = 0x01, sl_marked = 0x10 };
 511   void  set_on_scavenge_root_list()                    { _scavenge_root_state = sl_on_list; }
 512   void  clear_on_scavenge_root_list()                  { _scavenge_root_state = 0; }
 513   // assertion-checking and pruning logic uses the bits of _scavenge_root_state
 514 #ifndef PRODUCT
 515   void  set_scavenge_root_marked()                     { _scavenge_root_state |= sl_marked; }
 516   void  clear_scavenge_root_marked()                   { _scavenge_root_state &= ~sl_marked; }
 517   bool  scavenge_root_not_marked()                     { return (_scavenge_root_state &~ sl_on_list) == 0; }
 518   // N.B. there is no positive marked query, and we only use the not_marked query for asserts.
 519 #endif //PRODUCT
 520   nmethod* scavenge_root_link() const                  { return _scavenge_root_link; }
 521   void     set_scavenge_root_link(nmethod *n)          { _scavenge_root_link = n; }
 522 
 523  public:
 524 
 525   // Sweeper support
 526   long  stack_traversal_mark()                    { return _stack_traversal_mark; }
 527   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }
 528 
 529   // Exception cache support
 530   ExceptionCache* exception_cache() const         { return _exception_cache; }
 531   void set_exception_cache(ExceptionCache *ec)    { _exception_cache = ec; }
 532   address handler_for_exception_and_pc(Handle exception, address pc);
 533   void add_handler_for_exception_and_pc(Handle exception, address pc, address handler);
 534   void clean_exception_cache(BoolObjectClosure* is_alive);
 535 
 536   // implicit exceptions support
 537   address continuation_for_implicit_exception(address pc);
 538 
 539   // On-stack replacement support
 540   int   osr_entry_bci() const                     { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
 541   address  osr_entry() const                      { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
 542   void  invalidate_osr_method();
 543   nmethod* osr_link() const                       { return _osr_link; }
 544   void     set_osr_link(nmethod *n)               { _osr_link = n; }
 545 
 546   // tells whether frames described by this nmethod can be deoptimized
 547   // note: native wrappers cannot be deoptimized.
 548   bool can_be_deoptimized() const { return is_java_method(); }
 549 
 550   // Inline cache support
 551   void clear_inline_caches();
 552   void clear_ic_stubs();
 553   void cleanup_inline_caches();
 554   bool inlinecache_check_contains(address addr) const {
 555     return (addr >= code_begin() && addr < verified_entry_point());
 556   }
 557 
 558   // Verify calls to dead methods have been cleaned.
 559   void verify_clean_inline_caches();
 560   // Verify and count cached icholder relocations.
 561   int  verify_icholder_relocations();
 562   // Check that all metadata is still alive
 563   void verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive);
 564 
 565   // unlink and deallocate this nmethod
 566   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
 567   // expected to use any other private methods/data in this class.
 568 
 569  protected:
 570   void flush();
 571 
 572  public:
 573   // When true is returned, it is unsafe to remove this nmethod even if
 574   // it is a zombie, since the VM or the ServiceThread might still be
 575   // using it.
 576   bool is_locked_by_vm() const                    { return _lock_count >0; }
 577 
 578   // See comment at definition of _last_seen_on_stack
 579   void mark_as_seen_on_stack();
 580   bool can_convert_to_zombie();
 581 
 582   // Evolution support. We make old (discarded) compiled methods point to new Method*s.
 583   void set_method(Method* method) { _method = method; }
 584 








 585   // GC support
 586   void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
 587   //  The parallel versions are used by G1.
 588   bool do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred);
 589   void do_unloading_parallel_postponed(BoolObjectClosure* is_alive, bool unloading_occurred);
 590 
 591  private:
 592   //  Unload a nmethod if the *root object is dead.
 593   bool can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred);
 594   bool unload_if_dead_at(RelocIterator *iter_at_oop, BoolObjectClosure* is_alive, bool unloading_occurred);
 595 
 596  public:
 597   void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map,
 598                                      OopClosure* f);
 599   void oops_do(OopClosure* f) { oops_do(f, false); }
 600   void oops_do(OopClosure* f, bool allow_zombie);
 601   bool detect_scavenge_root_oops();
 602   void verify_scavenge_root_oops() PRODUCT_RETURN;
 603 
 604   bool test_set_oops_do_mark();
 605   static void oops_do_marking_prologue();
 606   static void oops_do_marking_epilogue();
 607   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
 608   bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
 609 
 610   // ScopeDesc for an instruction
 611   ScopeDesc* scope_desc_at(address pc);
 612 
 613  private:
 614   ScopeDesc* scope_desc_in(address begin, address end);
 615 
 616   address* orig_pc_addr(const frame* fr) { return (address*) ((address)fr->unextended_sp() + _orig_pc_offset); }
 617 
 618   PcDesc* find_pc_desc_internal(address pc, bool approximate);
 619 
 620   PcDesc* find_pc_desc(address pc, bool approximate) {
 621     PcDesc* desc = _pc_desc_cache.last_pc_desc();
 622     if (desc != NULL && desc->pc_offset() == pc - code_begin()) {
 623       return desc;
 624     }
 625     return find_pc_desc_internal(pc, approximate);
 626   }
 627 
 628  public:
 629   // ScopeDesc retrieval operation
 630   PcDesc* pc_desc_at(address pc)   { return find_pc_desc(pc, false); }
 631   // pc_desc_near returns the first PcDesc at or after the givne pc.
 632   PcDesc* pc_desc_near(address pc) { return find_pc_desc(pc, true); }
 633 
 634  public:
 635   // copying of debugging information
 636   void copy_scopes_pcs(PcDesc* pcs, int count);
 637   void copy_scopes_data(address buffer, int size);
 638 
 639   // Deopt
 640   // Return true is the PC is one would expect if the frame is being deopted.
 641   bool is_deopt_pc      (address pc) { return is_deopt_entry(pc) || is_deopt_mh_entry(pc); }
 642   bool is_deopt_entry   (address pc) { return pc == deopt_handler_begin(); }
 643   bool is_deopt_mh_entry(address pc) { return pc == deopt_mh_handler_begin(); }
 644   // Accessor/mutator for the original pc of a frame before a frame was deopted.
 645   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }
 646   void    set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }
 647 
 648   static address get_deopt_original_pc(const frame* fr);
 649 
 650   // MethodHandle
 651   bool is_method_handle_return(address return_pc);
 652 
 653   // jvmti support:
 654   void post_compiled_method_load_event();
 655   jmethodID get_and_cache_jmethod_id();
 656 
 657   // verify operations
 658   void verify();
 659   void verify_scopes();
 660   void verify_interrupt_point(address interrupt_point);
 661 
 662   // printing support
 663   void print()                          const;
 664   void print_code();
 665   void print_relocations()                        PRODUCT_RETURN;
 666   void print_pcs()                                PRODUCT_RETURN;
 667   void print_scopes()                             PRODUCT_RETURN;
 668   void print_dependencies()                       PRODUCT_RETURN;
 669   void print_value_on(outputStream* st) const     PRODUCT_RETURN;
 670   void print_calls(outputStream* st)              PRODUCT_RETURN;
 671   void print_handler_table()                      PRODUCT_RETURN;
 672   void print_nul_chk_table()                      PRODUCT_RETURN;
 673   void print_nmethod(bool print_code);
 674 
 675   // need to re-define this from CodeBlob else the overload hides it
 676   virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
 677   void print_on(outputStream* st, const char* msg) const;
 678 
 679   // Logging
 680   void log_identity(xmlStream* log) const;
 681   void log_new_nmethod() const;
 682   void log_state_change() const;
 683 
 684   // Prints block-level comments, including nmethod specific block labels:
 685   virtual void print_block_comment(outputStream* stream, address block_begin) const {
 686     print_nmethod_labels(stream, block_begin);
 687     CodeBlob::print_block_comment(stream, block_begin);
 688   }
 689   void print_nmethod_labels(outputStream* stream, address block_begin) const;
 690 
 691   // Prints a comment for one native instruction (reloc info, pc desc)
 692   void print_code_comment_on(outputStream* st, int column, address begin, address end);
 693   static void print_statistics()                  PRODUCT_RETURN;
 694 
 695   // Compiler task identification.  Note that all OSR methods
 696   // are numbered in an independent sequence if CICountOSR is true,
 697   // and native method wrappers are also numbered independently if
 698   // CICountNative is true.
 699   int  compile_id() const                         { return _compile_id; }
 700   const char* compile_kind() const;
 701 
 702   // tells if any of this method's dependencies have been invalidated
 703   // (this is expensive!)
 704   static void check_all_dependencies(DepChange& changes);
 705 
 706   // tells if this compiled method is dependent on the given changes,
 707   // and the changes have invalidated it
 708   bool check_dependency_on(DepChange& changes);
 709 
 710   // Evolution support. Tells if this compiled method is dependent on any of
 711   // methods m() of class dependee, such that if m() in dependee is replaced,
 712   // this compiled method will have to be deoptimized.
 713   bool is_evol_dependent_on(Klass* dependee);
 714 
 715   // Fast breakpoint support. Tells if this compiled method is
 716   // dependent on the given method. Returns true if this nmethod
 717   // corresponds to the given method as well.
 718   bool is_dependent_on_method(Method* dependee);
 719 
 720   // is it ok to patch at address?
 721   bool is_patchable_at(address instr_address);
 722 
 723   // UseBiasedLocking support
 724   ByteSize native_receiver_sp_offset() {
 725     return _native_receiver_sp_offset;
 726   }
 727   ByteSize native_basic_lock_sp_offset() {
 728     return _native_basic_lock_sp_offset;
 729   }
 730 
 731   // support for code generation
 732   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }
 733   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }
 734   static int state_offset()                       { return offset_of(nmethod, _state); }
 735 
 736   // RedefineClasses support.   Mark metadata in nmethods as on_stack so that
 737   // redefine classes doesn't purge it.
 738   static void mark_on_stack(nmethod* nm) {
 739     nm->metadata_do(Metadata::mark_on_stack);
 740   }
 741   void metadata_do(void f(Metadata*));
 742 };
 743 
 744 // Locks an nmethod so its code will not get removed and it will not
 745 // be made into a zombie, even if it is a not_entrant method. After the
 746 // nmethod becomes a zombie, if CompiledMethodUnload event processing
 747 // needs to be done, then lock_nmethod() is used directly to keep the
 748 // generated code from being reused too early.
 749 class nmethodLocker : public StackObj {
 750   nmethod* _nm;
 751 
 752  public:
 753 
 754   // note: nm can be NULL
 755   // Only JvmtiDeferredEvent::compiled_method_unload_event()
 756   // should pass zombie_ok == true.
 757   static void lock_nmethod(nmethod* nm, bool zombie_ok = false);
 758   static void unlock_nmethod(nmethod* nm); // (ditto)
 759 
 760   nmethodLocker(address pc); // derive nm from pc
 761   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
 762   nmethodLocker() { _nm = NULL; }
 763   ~nmethodLocker() { unlock_nmethod(_nm); }
 764 
 765   nmethod* code() { return _nm; }
 766   void set_code(nmethod* new_nm) {
 767     unlock_nmethod(_nm);   // note:  This works even if _nm==new_nm.
 768     _nm = new_nm;
 769     lock_nmethod(_nm);
 770   }
 771 };
 772 
 773 #endif // SHARE_VM_CODE_NMETHOD_HPP
--- EOF ---