1 /*

        2  * Copyright 1997-2010 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

       20  * CA 95054 USA or visit www.sun.com if you need additional information or

       21  * have any questions.

       22  *

       23  */

       24 

       25 // This class is used internally by nmethods, to cache

       26 // exception/pc/handler information.

       27 

       28 class ExceptionCache : public CHeapObj {

       29   friend class VMStructs;

       30  private:

       31   static address _unwind_handler;

       32   enum { cache_size = 16 };

       33   klassOop _exception_type;

       34   address  _pc[cache_size];

       35   address  _handler[cache_size];

       36   int      _count;

       37   ExceptionCache* _next;

       38 

       39   address pc_at(int index)                     { assert(index >= 0 && index < count(),""); return _pc[index]; }

       40   void    set_pc_at(int index, address a)      { assert(index >= 0 && index < cache_size,""); _pc[index] = a; }

       41   address handler_at(int index)                { assert(index >= 0 && index < count(),""); return _handler[index]; }

       42   void    set_handler_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _handler[index] = a; }

       43   int     count()                              { return _count; }

       44   void    increment_count()                    { _count++; }

       45 

       46  public:

       47 

       48   ExceptionCache(Handle exception, address pc, address handler);

       49 

       50   klassOop  exception_type()                { return _exception_type; }

       51   klassOop* exception_type_addr()           { return &_exception_type; }

       52   ExceptionCache* next()                    { return _next; }

       53   void      set_next(ExceptionCache *ec)    { _next = ec; }

       54 

       55   address match(Handle exception, address pc);

       56   bool    match_exception_with_space(Handle exception) ;

       57   address test_address(address addr);

       58   bool    add_address_and_handler(address addr, address handler) ;

       59 

       60   static address unwind_handler() { return _unwind_handler; }

       61 };

       62 

       63 

       64 // cache pc descs found in earlier inquiries

       65 class PcDescCache VALUE_OBJ_CLASS_SPEC {

       66   friend class VMStructs;

       67  private:

       68   enum { cache_size = 4 };

       69   PcDesc* _last_pc_desc;         // most recent pc_desc found

       70   PcDesc* _pc_descs[cache_size]; // last cache_size pc_descs found

       71  public:

       72   PcDescCache() { debug_only(_last_pc_desc = NULL); }

       73   void    reset_to(PcDesc* initial_pc_desc);

       74   PcDesc* find_pc_desc(int pc_offset, bool approximate);

       75   void    add_pc_desc(PcDesc* pc_desc);

       76   PcDesc* last_pc_desc() { return _last_pc_desc; }

       77 };

       78 

       79 

       80 // nmethods (native methods) are the compiled code versions of Java methods.

       81 

       82 struct nmFlags {

       83   friend class VMStructs;

       84   unsigned int version:8;                    // version number (0 = first version)

       85   unsigned int level:4;                      // optimization level

       86   unsigned int age:4;                        // age (in # of sweep steps)

       87 

       88   unsigned int state:2;                      // {alive, zombie, unloaded)

       89 

       90   unsigned int isUncommonRecompiled:1;       // recompiled because of uncommon trap?

       91   unsigned int isToBeRecompiled:1;           // to be recompiled as soon as it matures

       92   unsigned int hasFlushedDependencies:1;     // Used for maintenance of dependencies

       93   unsigned int markedForReclamation:1;       // Used by NMethodSweeper

       94 

       95   unsigned int has_unsafe_access:1;          // May fault due to unsafe access.

       96   unsigned int has_method_handle_invokes:1;  // Has this method MethodHandle invokes?

       97 

       98   unsigned int speculatively_disconnected:1; // Marked for potential unload

       99 

      100   void clear();

      101 };

      102 

      103 

      104 // A nmethod contains:

      105 //  - header                 (the nmethod structure)

      106 //  [Relocation]

      107 //  - relocation information

      108 //  - constant part          (doubles, longs and floats used in nmethod)

      109 //  [Code]

      110 //  - code body

      111 //  - exception handler

      112 //  - stub code

      113 //  [Debugging information]

      114 //  - oop array

      115 //  - data array

      116 //  - pcs

      117 //  [Exception handler table]

      118 //  - handler entry point array

      119 //  [Implicit Null Pointer exception table]

      120 //  - implicit null table array

      121 

      122 class Dependencies;

      123 class ExceptionHandlerTable;

      124 class ImplicitExceptionTable;

      125 class AbstractCompiler;

      126 class xmlStream;

      127 

      128 class nmethod : public CodeBlob {

      129   friend class VMStructs;

      130   friend class NMethodSweeper;

      131   friend class CodeCache;  // non-perm oops

      132  private:

      133   // Shared fields for all nmethod's

      134   static int _zombie_instruction_size;

      135 

      136   methodOop _method;

      137   int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method

      138 

      139   // To support simple linked-list chaining of nmethods:

      140   nmethod*  _osr_link;         // from instanceKlass::osr_nmethods_head

      141   nmethod*  _scavenge_root_link; // from CodeCache::scavenge_root_nmethods

      142   nmethod*  _saved_nmethod_link; // from CodeCache::speculatively_disconnect

      143 

      144   static nmethod* volatile _oops_do_mark_nmethods;

      145   nmethod*        volatile _oops_do_mark_link;

      146 

      147   AbstractCompiler* _compiler; // The compiler which compiled this nmethod

      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 #ifdef HAVE_DTRACE_H

      161   int _trap_offset;

      162 #endif // def HAVE_DTRACE_H

      163   int _stub_offset;

      164   int _consts_offset;

      165   int _scopes_data_offset;

      166   int _scopes_pcs_offset;

      167   int _dependencies_offset;

      168   int _handler_table_offset;

      169   int _nul_chk_table_offset;

      170   int _nmethod_end_offset;

      171 

      172   // location in frame (offset for sp) that deopt can store the original

      173   // pc during a deopt.

      174   int _orig_pc_offset;

      175 

      176   int _compile_id;                     // which compilation made this nmethod

      177   int _comp_level;                     // compilation level

      178 

      179   // offsets for entry points

      180   address _entry_point;                // entry point with class check

      181   address _verified_entry_point;       // entry point without class check

      182   address _osr_entry_point;            // entry point for on stack replacement

      183 

      184   nmFlags flags;           // various flags to keep track of nmethod state

      185   bool _markedForDeoptimization;       // Used for stack deoptimization

      186   enum { alive        = 0,

      187          not_entrant  = 1, // uncommon trap has happened but activations may still exist

      188          zombie       = 2,

      189          unloaded     = 3 };

      190 

      191   // used by jvmti to track if an unload event has been posted for this nmethod.

      192   bool _unload_reported;

      193 

      194   jbyte _scavenge_root_state;

      195 

      196   NOT_PRODUCT(bool _has_debug_info; )

      197 

      198   // Nmethod Flushing lock (if non-zero, then the nmethod is not removed)

      199   jint  _lock_count;

      200 

      201   // not_entrant method removal. Each mark_sweep pass will update

      202   // this mark to current sweep invocation count if it is seen on the

      203   // stack.  An not_entrant method can be removed when there is no

      204   // more activations, i.e., when the _stack_traversal_mark is less than

      205   // current sweep traversal index.

      206   long _stack_traversal_mark;

      207 

      208   ExceptionCache *_exception_cache;

      209   PcDescCache     _pc_desc_cache;

      210 

      211   // These are only used for compiled synchronized native methods to

      212   // locate the owner and stack slot for the BasicLock so that we can

      213   // properly revoke the bias of the owner if necessary. They are

      214   // needed because there is no debug information for compiled native

      215   // wrappers and the oop maps are insufficient to allow

      216   // frame::retrieve_receiver() to work. Currently they are expected

      217   // to be byte offsets from the Java stack pointer for maximum code

      218   // sharing between platforms. Note that currently biased locking

      219   // will never cause Class instances to be biased but this code

      220   // handles the static synchronized case as well.

      221   ByteSize _compiled_synchronized_native_basic_lock_owner_sp_offset;

      222   ByteSize _compiled_synchronized_native_basic_lock_sp_offset;

      223 

      224   friend class nmethodLocker;

      225 

      226   // For native wrappers

      227   nmethod(methodOop method,

      228           int nmethod_size,

      229           CodeOffsets* offsets,

      230           CodeBuffer *code_buffer,

      231           int frame_size,

      232           ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */

      233           ByteSize basic_lock_sp_offset,       /* synchronized natives only */

      234           OopMapSet* oop_maps);

      235 

      236 #ifdef HAVE_DTRACE_H

      237   // For native wrappers

      238   nmethod(methodOop method,

      239           int nmethod_size,

      240           CodeOffsets* offsets,

      241           CodeBuffer *code_buffer,

      242           int frame_size);

      243 #endif // def HAVE_DTRACE_H

      244 

      245   // Creation support

      246   nmethod(methodOop method,

      247           int nmethod_size,

      248           int compile_id,

      249           int entry_bci,

      250           CodeOffsets* offsets,

      251           int orig_pc_offset,

      252           DebugInformationRecorder *recorder,

      253           Dependencies* dependencies,

      254           CodeBuffer *code_buffer,

      255           int frame_size,

      256           OopMapSet* oop_maps,

      257           ExceptionHandlerTable* handler_table,

      258           ImplicitExceptionTable* nul_chk_table,

      259           AbstractCompiler* compiler,

      260           int comp_level);

      261 

      262   // helper methods

      263   void* operator new(size_t size, int nmethod_size);

      264 

      265   const char* reloc_string_for(u_char* begin, u_char* end);

      266   // Returns true if this thread changed the state of the nmethod or

      267   // false if another thread performed the transition.

      268   bool make_not_entrant_or_zombie(unsigned int state);

      269   void inc_decompile_count();

      270 

      271   // used to check that writes to nmFlags are done consistently.

      272   static void check_safepoint() PRODUCT_RETURN;

      273 

      274   // Used to manipulate the exception cache

      275   void add_exception_cache_entry(ExceptionCache* new_entry);

      276   ExceptionCache* exception_cache_entry_for_exception(Handle exception);

      277 

      278   // Inform external interfaces that a compiled method has been unloaded

      279   inline void post_compiled_method_unload();

      280 

      281  public:

      282   // create nmethod with entry_bci

      283   static nmethod* new_nmethod(methodHandle method,

      284                               int compile_id,

      285                               int entry_bci,

      286                               CodeOffsets* offsets,

      287                               int orig_pc_offset,

      288                               DebugInformationRecorder* recorder,

      289                               Dependencies* dependencies,

      290                               CodeBuffer *code_buffer,

      291                               int frame_size,

      292                               OopMapSet* oop_maps,

      293                               ExceptionHandlerTable* handler_table,

      294                               ImplicitExceptionTable* nul_chk_table,

      295                               AbstractCompiler* compiler,

      296                               int comp_level);

      297 

      298   static nmethod* new_native_nmethod(methodHandle method,

      299                                      CodeBuffer *code_buffer,

      300                                      int vep_offset,

      301                                      int frame_complete,

      302                                      int frame_size,

      303                                      ByteSize receiver_sp_offset,

      304                                      ByteSize basic_lock_sp_offset,

      305                                      OopMapSet* oop_maps);

      306 

      307 #ifdef HAVE_DTRACE_H

      308   // The method we generate for a dtrace probe has to look

      309   // like an nmethod as far as the rest of the system is concerned

      310   // which is somewhat unfortunate.

      311   static nmethod* new_dtrace_nmethod(methodHandle method,

      312                                      CodeBuffer *code_buffer,

      313                                      int vep_offset,

      314                                      int trap_offset,

      315                                      int frame_complete,

      316                                      int frame_size);

      317 

      318   int trap_offset() const      { return _trap_offset; }

      319   address trap_address() const { return code_begin() + _trap_offset; }

      320 

      321 #endif // def HAVE_DTRACE_H

      322 

      323   // accessors

      324   methodOop method() const                        { return _method; }

      325   AbstractCompiler* compiler() const              { return _compiler; }

      326 

      327 #ifndef PRODUCT

      328   bool has_debug_info() const                     { return _has_debug_info; }

      329   void set_has_debug_info(bool f)                 { _has_debug_info = false; }

      330 #endif // NOT PRODUCT

      331 

      332   // type info

      333   bool is_nmethod() const                         { return true; }

      334   bool is_java_method() const                     { return !method()->is_native(); }

      335   bool is_native_method() const                   { return method()->is_native(); }

      336   bool is_osr_method() const                      { return _entry_bci != InvocationEntryBci; }

      337 

      338   bool is_compiled_by_c1() const;

      339   bool is_compiled_by_c2() const;

      340 

      341   // boundaries for different parts

      342   address code_begin            () const          { return _entry_point; }

      343   address code_end              () const          { return           header_begin() + _stub_offset          ; }

      344   address exception_begin       () const          { return           header_begin() + _exception_offset     ; }

      345   address deopt_handler_begin   () const          { return           header_begin() + _deoptimize_offset    ; }

      346   address deopt_mh_handler_begin() const          { return           header_begin() + _deoptimize_mh_offset ; }

      347   address unwind_handler_begin  () const          { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }

      348   address stub_begin            () const          { return           header_begin() + _stub_offset          ; }

      349   address stub_end              () const          { return           header_begin() + _consts_offset        ; }

      350   address consts_begin          () const          { return           header_begin() + _consts_offset        ; }

      351   address consts_end            () const          { return           header_begin() + _scopes_data_offset   ; }

      352   address scopes_data_begin     () const          { return           header_begin() + _scopes_data_offset   ; }

      353   address scopes_data_end       () const          { return           header_begin() + _scopes_pcs_offset    ; }

      354   PcDesc* scopes_pcs_begin      () const          { return (PcDesc*)(header_begin() + _scopes_pcs_offset   ); }

      355   PcDesc* scopes_pcs_end        () const          { return (PcDesc*)(header_begin() + _dependencies_offset) ; }

      356   address dependencies_begin    () const          { return           header_begin() + _dependencies_offset  ; }

      357   address dependencies_end      () const          { return           header_begin() + _handler_table_offset ; }

      358   address handler_table_begin   () const          { return           header_begin() + _handler_table_offset ; }

      359   address handler_table_end     () const          { return           header_begin() + _nul_chk_table_offset ; }

      360   address nul_chk_table_begin   () const          { return           header_begin() + _nul_chk_table_offset ; }

      361   address nul_chk_table_end     () const          { return           header_begin() + _nmethod_end_offset   ; }

      362 

      363   int code_size         () const                  { return      code_end         () -      code_begin         (); }

      364   int stub_size         () const                  { return      stub_end         () -      stub_begin         (); }

      365   int consts_size       () const                  { return      consts_end       () -      consts_begin       (); }

      366   int scopes_data_size  () const                  { return      scopes_data_end  () -      scopes_data_begin  (); }

      367   int scopes_pcs_size   () const                  { return (intptr_t)scopes_pcs_end   () - (intptr_t)scopes_pcs_begin   (); }

      368   int dependencies_size () const                  { return      dependencies_end () -      dependencies_begin (); }

      369   int handler_table_size() const                  { return      handler_table_end() -      handler_table_begin(); }

      370   int nul_chk_table_size() const                  { return      nul_chk_table_end() -      nul_chk_table_begin(); }

      371 

      372   int total_size        () const;

      373 

      374   bool code_contains         (address addr) const { return code_begin         () <= addr && addr < code_end         (); }

      375   bool stub_contains         (address addr) const { return stub_begin         () <= addr && addr < stub_end         (); }

      376   bool consts_contains       (address addr) const { return consts_begin       () <= addr && addr < consts_end       (); }

      377   bool scopes_data_contains  (address addr) const { return scopes_data_begin  () <= addr && addr < scopes_data_end  (); }

      378   bool scopes_pcs_contains   (PcDesc* addr) const { return scopes_pcs_begin   () <= addr && addr < scopes_pcs_end   (); }

      379   bool handler_table_contains(address addr) const { return handler_table_begin() <= addr && addr < handler_table_end(); }

      380   bool nul_chk_table_contains(address addr) const { return nul_chk_table_begin() <= addr && addr < nul_chk_table_end(); }

      381 

      382   // entry points

      383   address entry_point() const                     { return _entry_point;             } // normal entry point

      384   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct

      385 

      386   // flag accessing and manipulation

      387   bool  is_in_use() const                         { return flags.state == alive; }

      388   bool  is_alive() const                          { return flags.state == alive || flags.state == not_entrant; }

      389   bool  is_not_entrant() const                    { return flags.state == not_entrant; }

      390   bool  is_zombie() const                         { return flags.state == zombie; }

      391   bool  is_unloaded() const                       { return flags.state == unloaded;   }

      392 

      393   // Make the nmethod non entrant. The nmethod will continue to be

      394   // alive.  It is used when an uncommon trap happens.  Returns true

      395   // if this thread changed the state of the nmethod or false if

      396   // another thread performed the transition.

      397   bool  make_not_entrant()                        { return make_not_entrant_or_zombie(not_entrant); }

      398   bool  make_zombie()                             { return make_not_entrant_or_zombie(zombie); }

      399 

      400   // used by jvmti to track if the unload event has been reported

      401   bool  unload_reported()                         { return _unload_reported; }

      402   void  set_unload_reported()                     { _unload_reported = true; }

      403 

      404   bool  is_marked_for_deoptimization() const      { return _markedForDeoptimization; }

      405   void  mark_for_deoptimization()                 { _markedForDeoptimization = true; }

      406 

      407   void  make_unloaded(BoolObjectClosure* is_alive, oop cause);

      408 

      409   bool has_dependencies()                         { return dependencies_size() != 0; }

      410   void flush_dependencies(BoolObjectClosure* is_alive);

      411   bool  has_flushed_dependencies()                { return flags.hasFlushedDependencies; }

      412   void  set_has_flushed_dependencies()            {

      413     check_safepoint();

      414     assert(!has_flushed_dependencies(), "should only happen once");

      415     flags.hasFlushedDependencies = 1;

      416   }

      417 

      418   bool  is_marked_for_reclamation() const         { return flags.markedForReclamation; }

      419   void  mark_for_reclamation()                    { check_safepoint(); flags.markedForReclamation = 1; }

      420   void  unmark_for_reclamation()                  { check_safepoint(); flags.markedForReclamation = 0; }

      421 

      422   bool  has_unsafe_access() const                 { return flags.has_unsafe_access; }

      423   void  set_has_unsafe_access(bool z)             { flags.has_unsafe_access = z; }

      424 

      425   bool  has_method_handle_invokes() const         { return flags.has_method_handle_invokes; }

      426   void  set_has_method_handle_invokes(bool z)     { flags.has_method_handle_invokes = z; }

      427 

      428   bool  is_speculatively_disconnected() const     { return flags.speculatively_disconnected; }

      429   void  set_speculatively_disconnected(bool z)     { flags.speculatively_disconnected = z; }

      430 

      431   int   level() const                             { return flags.level; }

      432   void  set_level(int newLevel)                   { check_safepoint(); flags.level = newLevel; }

      433 

      434   int   comp_level() const                        { return _comp_level; }

      435 

      436   int   version() const                           { return flags.version; }

      437   void  set_version(int v);

      438 

      439   // Non-perm oop support

      440   bool  on_scavenge_root_list() const                  { return (_scavenge_root_state & 1) != 0; }

      441  protected:

      442   enum { npl_on_list = 0x01, npl_marked = 0x10 };

      443   void  set_on_scavenge_root_list()                    { _scavenge_root_state = npl_on_list; }

      444   void  clear_on_scavenge_root_list()                  { _scavenge_root_state = 0; }

      445   // assertion-checking and pruning logic uses the bits of _scavenge_root_state

      446 #ifndef PRODUCT

      447   void  set_scavenge_root_marked()                     { _scavenge_root_state |= npl_marked; }

      448   void  clear_scavenge_root_marked()                   { _scavenge_root_state &= ~npl_marked; }

      449   bool  scavenge_root_not_marked()                     { return (_scavenge_root_state &~ npl_on_list) == 0; }

      450   // N.B. there is no positive marked query, and we only use the not_marked query for asserts.

      451 #endif //PRODUCT

      452   nmethod* scavenge_root_link() const                  { return _scavenge_root_link; }

      453   void     set_scavenge_root_link(nmethod *n)          { _scavenge_root_link = n; }

      454 

      455   nmethod* saved_nmethod_link() const                  { return _saved_nmethod_link; }

      456   void     set_saved_nmethod_link(nmethod *n)          { _saved_nmethod_link = n; }

      457 

      458  public:

      459 

      460   // Sweeper support

      461   long  stack_traversal_mark()                    { return _stack_traversal_mark; }

      462   void  set_stack_traversal_mark(long l)          { _stack_traversal_mark = l; }

      463 

      464   // Exception cache support

      465   ExceptionCache* exception_cache() const         { return _exception_cache; }

      466   void set_exception_cache(ExceptionCache *ec)    { _exception_cache = ec; }

      467   address handler_for_exception_and_pc(Handle exception, address pc);

      468   void add_handler_for_exception_and_pc(Handle exception, address pc, address handler);

      469   void remove_from_exception_cache(ExceptionCache* ec);

      470 

      471   // implicit exceptions support

      472   address continuation_for_implicit_exception(address pc);

      473 

      474   // On-stack replacement support

      475   int   osr_entry_bci() const                     { assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod"); return _entry_bci; }

      476   address  osr_entry() const                      { assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod"); return _osr_entry_point; }

      477   void  invalidate_osr_method();

      478   nmethod* osr_link() const                       { return _osr_link; }

      479   void     set_osr_link(nmethod *n)               { _osr_link = n; }

      480 

      481   // tells whether frames described by this nmethod can be deoptimized

      482   // note: native wrappers cannot be deoptimized.

      483   bool can_be_deoptimized() const { return is_java_method(); }

      484 

      485   // Inline cache support

      486   void clear_inline_caches();

      487   void cleanup_inline_caches();

      488   bool inlinecache_check_contains(address addr) const {

      489     return (addr >= instructions_begin() && addr < verified_entry_point());

      490   }

      491 

      492   // unlink and deallocate this nmethod

      493   // Only NMethodSweeper class is expected to use this. NMethodSweeper is not

      494   // expected to use any other private methods/data in this class.

      495 

      496  protected:

      497   void flush();

      498 

      499  public:

      500   // If returning true, it is unsafe to remove this nmethod even though it is a zombie

      501   // nmethod, since the VM might have a reference to it. Should only be called from a  safepoint.

      502   bool is_locked_by_vm() const                    { return _lock_count >0; }

      503 

      504   // See comment at definition of _last_seen_on_stack

      505   void mark_as_seen_on_stack();

      506   bool can_not_entrant_be_converted();

      507 

      508   // Evolution support. We make old (discarded) compiled methods point to new methodOops.

      509   void set_method(methodOop method) { _method = method; }

      510 

      511   // GC support

      512   void do_unloading(BoolObjectClosure* is_alive, OopClosure* keep_alive,

      513                     bool unloading_occurred);

      514   bool can_unload(BoolObjectClosure* is_alive, OopClosure* keep_alive,

      515                   oop* root, bool unloading_occurred);

      516 

      517   void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map,

      518                                      OopClosure* f);

      519   virtual void oops_do(OopClosure* f) { oops_do(f, false); }

      520   void         oops_do(OopClosure* f, bool do_strong_roots_only);

      521   bool detect_scavenge_root_oops();

      522   void verify_scavenge_root_oops() PRODUCT_RETURN;

      523 

      524   bool test_set_oops_do_mark();

      525   static void oops_do_marking_prologue();

      526   static void oops_do_marking_epilogue();

      527   static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }

      528   DEBUG_ONLY(bool test_oops_do_mark() { return _oops_do_mark_link != NULL; })

      529 

      530   // ScopeDesc for an instruction

      531   ScopeDesc* scope_desc_at(address pc);

      532 

      533  private:

      534   ScopeDesc* scope_desc_in(address begin, address end);

      535 

      536   address* orig_pc_addr(const frame* fr) { return (address*) ((address)fr->unextended_sp() + _orig_pc_offset); }

      537 

      538   PcDesc* find_pc_desc_internal(address pc, bool approximate);

      539 

      540   PcDesc* find_pc_desc(address pc, bool approximate) {

      541     PcDesc* desc = _pc_desc_cache.last_pc_desc();

      542     if (desc != NULL && desc->pc_offset() == pc - instructions_begin()) {

      543       return desc;

      544     }

      545     return find_pc_desc_internal(pc, approximate);

      546   }

      547 

      548  public:

      549   // ScopeDesc retrieval operation

      550   PcDesc* pc_desc_at(address pc)   { return find_pc_desc(pc, false); }

      551   // pc_desc_near returns the first PcDesc at or after the givne pc.

      552   PcDesc* pc_desc_near(address pc) { return find_pc_desc(pc, true); }

      553 

      554  public:

      555   // copying of debugging information

      556   void copy_scopes_pcs(PcDesc* pcs, int count);

      557   void copy_scopes_data(address buffer, int size);

      558 

      559   // Deopt

      560   // Return true is the PC is one would expect if the frame is being deopted.

      561   bool is_deopt_pc      (address pc) { return is_deopt_entry(pc) || is_deopt_mh_entry(pc); }

      562   bool is_deopt_entry   (address pc) { return pc == deopt_handler_begin(); }

      563   bool is_deopt_mh_entry(address pc) { return pc == deopt_mh_handler_begin(); }

      564   // Accessor/mutator for the original pc of a frame before a frame was deopted.

      565   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }

      566   void    set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }

      567 

      568   static address get_deopt_original_pc(const frame* fr);

      569 

      570   // MethodHandle

      571   bool is_method_handle_return(address return_pc);

      572 

      573   // jvmti support:

      574   void post_compiled_method_load_event();

      575 

      576   // verify operations

      577   void verify();

      578   void verify_scopes();

      579   void verify_interrupt_point(address interrupt_point);

      580 

      581   // printing support

      582   void print()                          const;

      583   void print_code();

      584   void print_relocations()                        PRODUCT_RETURN;

      585   void print_pcs()                                PRODUCT_RETURN;

      586   void print_scopes()                             PRODUCT_RETURN;

      587   void print_dependencies()                       PRODUCT_RETURN;

      588   void print_value_on(outputStream* st) const     PRODUCT_RETURN;

      589   void print_calls(outputStream* st)              PRODUCT_RETURN;

      590   void print_handler_table()                      PRODUCT_RETURN;

      591   void print_nul_chk_table()                      PRODUCT_RETURN;

      592   void print_nmethod(bool print_code);

      593 

      594   void print_on(outputStream* st, const char* title) const;

      595 

      596   // Logging

      597   void log_identity(xmlStream* log) const;

      598   void log_new_nmethod() const;

      599   void log_state_change() const;

      600 

      601   // Prints block-level comments, including nmethod specific block labels:

      602   virtual void print_block_comment(outputStream* stream, address block_begin) {

      603     print_nmethod_labels(stream, block_begin);

      604     CodeBlob::print_block_comment(stream, block_begin);

      605   }

      606   void print_nmethod_labels(outputStream* stream, address block_begin);

      607 

      608   // Prints a comment for one native instruction (reloc info, pc desc)

      609   void print_code_comment_on(outputStream* st, int column, address begin, address end);

      610   static void print_statistics()                  PRODUCT_RETURN;

      611 

      612   // Compiler task identification.  Note that all OSR methods

      613   // are numbered in an independent sequence if CICountOSR is true,

      614   // and native method wrappers are also numbered independently if

      615   // CICountNative is true.

      616   int  compile_id() const                         { return _compile_id; }

      617   const char* compile_kind() const;

      618 

      619   // For debugging

      620   // CompiledIC*    IC_at(char* p) const;

      621   // PrimitiveIC*   primitiveIC_at(char* p) const;

      622   oop embeddedOop_at(address p);

      623 

      624   // tells if any of this method's dependencies have been invalidated

      625   // (this is expensive!)

      626   bool check_all_dependencies();

      627 

      628   // tells if this compiled method is dependent on the given changes,

      629   // and the changes have invalidated it

      630   bool check_dependency_on(DepChange& changes);

      631 

      632   // Evolution support. Tells if this compiled method is dependent on any of

      633   // methods m() of class dependee, such that if m() in dependee is replaced,

      634   // this compiled method will have to be deoptimized.

      635   bool is_evol_dependent_on(klassOop dependee);

      636 

      637   // Fast breakpoint support. Tells if this compiled method is

      638   // dependent on the given method. Returns true if this nmethod

      639   // corresponds to the given method as well.

      640   bool is_dependent_on_method(methodOop dependee);

      641 

      642   // is it ok to patch at address?

      643   bool is_patchable_at(address instr_address);

      644 

      645   // UseBiasedLocking support

      646   ByteSize compiled_synchronized_native_basic_lock_owner_sp_offset() {

      647     return _compiled_synchronized_native_basic_lock_owner_sp_offset;

      648   }

      649   ByteSize compiled_synchronized_native_basic_lock_sp_offset() {

      650     return _compiled_synchronized_native_basic_lock_sp_offset;

      651   }

      652 

      653   // support for code generation

      654   static int verified_entry_point_offset()        { return offset_of(nmethod, _verified_entry_point); }

      655   static int osr_entry_point_offset()             { return offset_of(nmethod, _osr_entry_point); }

      656   static int entry_bci_offset()                   { return offset_of(nmethod, _entry_bci); }

      657 

      658 };

      659 

      660 // Locks an nmethod so its code will not get removed, even if it is a zombie/not_entrant method

      661 class nmethodLocker : public StackObj {

      662   nmethod* _nm;

      663 

      664   static void lock_nmethod(nmethod* nm);   // note: nm can be NULL

      665   static void unlock_nmethod(nmethod* nm); // (ditto)

      666 

      667  public:

      668   nmethodLocker(address pc); // derive nm from pc

      669   nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }

      670   nmethodLocker() { _nm = NULL; }

      671   ~nmethodLocker() { unlock_nmethod(_nm); }

      672 

      673   nmethod* code() { return _nm; }

      674   void set_code(nmethod* new_nm) {

      675     unlock_nmethod(_nm);   // note:  This works even if _nm==new_nm.

      676     _nm = new_nm;

      677     lock_nmethod(_nm);

      678   }

      679 };