src/share/vm/oops/instanceKlass.hpp

Fri, 16 Nov 2012 09:19:12 -0500

author
coleenp
date
Fri, 16 Nov 2012 09:19:12 -0500
changeset 4280
80e866b1d053
parent 4267
bd7a7ce2e264
child 4345
30866cd626b0
child 4400
ecd24264898b
permissions
-rw-r--r--

Merge

     1 /*
     2  * Copyright (c) 1997, 2012, 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  */
    25 #ifndef SHARE_VM_OOPS_INSTANCEKLASS_HPP
    26 #define SHARE_VM_OOPS_INSTANCEKLASS_HPP
    28 #include "classfile/classLoaderData.hpp"
    29 #include "oops/annotations.hpp"
    30 #include "oops/constMethod.hpp"
    31 #include "oops/fieldInfo.hpp"
    32 #include "oops/instanceOop.hpp"
    33 #include "oops/klassVtable.hpp"
    34 #include "runtime/handles.hpp"
    35 #include "runtime/os.hpp"
    36 #include "utilities/accessFlags.hpp"
    37 #include "utilities/bitMap.inline.hpp"
    39 // An InstanceKlass is the VM level representation of a Java class.
    40 // It contains all information needed for at class at execution runtime.
    42 //  InstanceKlass layout:
    43 //    [C++ vtbl pointer           ] Klass
    44 //    [subtype cache              ] Klass
    45 //    [instance size              ] Klass
    46 //    [java mirror                ] Klass
    47 //    [super                      ] Klass
    48 //    [access_flags               ] Klass
    49 //    [name                       ] Klass
    50 //    [first subklass             ] Klass
    51 //    [next sibling               ] Klass
    52 //    [array klasses              ]
    53 //    [methods                    ]
    54 //    [local interfaces           ]
    55 //    [transitive interfaces      ]
    56 //    [fields                     ]
    57 //    [constants                  ]
    58 //    [class loader               ]
    59 //    [protection domain          ]
    60 //    [signers                    ]
    61 //    [source file name           ]
    62 //    [inner classes              ]
    63 //    [static field size          ]
    64 //    [nonstatic field size       ]
    65 //    [static oop fields size     ]
    66 //    [nonstatic oop maps size    ]
    67 //    [has finalize method        ]
    68 //    [deoptimization mark bit    ]
    69 //    [initialization state       ]
    70 //    [initializing thread        ]
    71 //    [Java vtable length         ]
    72 //    [oop map cache (stack maps) ]
    73 //    [EMBEDDED Java vtable             ] size in words = vtable_len
    74 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
    75 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
    76 //      indicating where oops are located in instances of this klass.
    77 //    [EMBEDDED implementor of the interface] only exist for interface
    78 //    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
    81 // forward declaration for class -- see below for definition
    82 class SuperTypeClosure;
    83 class JNIid;
    84 class jniIdMapBase;
    85 class BreakpointInfo;
    86 class fieldDescriptor;
    87 class DepChange;
    88 class nmethodBucket;
    89 class PreviousVersionNode;
    90 class JvmtiCachedClassFieldMap;
    92 // This is used in iterators below.
    93 class FieldClosure: public StackObj {
    94 public:
    95   virtual void do_field(fieldDescriptor* fd) = 0;
    96 };
    98 #ifndef PRODUCT
    99 // Print fields.
   100 // If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
   101 class FieldPrinter: public FieldClosure {
   102    oop _obj;
   103    outputStream* _st;
   104  public:
   105    FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
   106    void do_field(fieldDescriptor* fd);
   107 };
   108 #endif  // !PRODUCT
   110 // ValueObjs embedded in klass. Describes where oops are located in instances of
   111 // this klass.
   112 class OopMapBlock VALUE_OBJ_CLASS_SPEC {
   113  public:
   114   // Byte offset of the first oop mapped by this block.
   115   int offset() const          { return _offset; }
   116   void set_offset(int offset) { _offset = offset; }
   118   // Number of oops in this block.
   119   uint count() const         { return _count; }
   120   void set_count(uint count) { _count = count; }
   122   // sizeof(OopMapBlock) in HeapWords.
   123   static const int size_in_words() {
   124     return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
   125       LogHeapWordSize;
   126   }
   128  private:
   129   int  _offset;
   130   uint _count;
   131 };
   133 class InstanceKlass: public Klass {
   134   friend class VMStructs;
   135   friend class ClassFileParser;
   136   friend class CompileReplay;
   138  protected:
   139   // Constructor
   140   InstanceKlass(int vtable_len,
   141                 int itable_len,
   142                 int static_field_size,
   143                 int nonstatic_oop_map_size,
   144                 ReferenceType rt,
   145                 AccessFlags access_flags,
   146                 bool is_anonymous);
   147  public:
   148   static Klass* allocate_instance_klass(ClassLoaderData* loader_data,
   149                                           int vtable_len,
   150                                           int itable_len,
   151                                           int static_field_size,
   152                                           int nonstatic_oop_map_size,
   153                                           ReferenceType rt,
   154                                           AccessFlags access_flags,
   155                                           Symbol* name,
   156                                         Klass* super_klass,
   157                                           KlassHandle host_klass,
   158                                           TRAPS);
   160   InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
   162   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
   163   // of the class loading & initialization procedure, and the use of the states.
   164   enum ClassState {
   165     allocated,                          // allocated (but not yet linked)
   166     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
   167     linked,                             // successfully linked/verified (but not initialized yet)
   168     being_initialized,                  // currently running class initializer
   169     fully_initialized,                  // initialized (successfull final state)
   170     initialization_error                // error happened during initialization
   171   };
   173  protected:
   174   // Protection domain.
   175   oop             _protection_domain;
   176   // Class signers.
   177   objArrayOop     _signers;
   178   // Initialization lock.  Must be one per class and it has to be a VM internal
   179   // object so java code cannot lock it (like the mirror)
   180   // It has to be an object not a Mutex because it's held through java calls.
   181   volatile oop    _init_lock;
   183   // Annotations for this class
   184   Annotations*    _annotations;
   185   // Array classes holding elements of this class.
   186   Klass*          _array_klasses;
   187   // Constant pool for this class.
   188   ConstantPool* _constants;
   189   // The InnerClasses attribute and EnclosingMethod attribute. The
   190   // _inner_classes is an array of shorts. If the class has InnerClasses
   191   // attribute, then the _inner_classes array begins with 4-tuples of shorts
   192   // [inner_class_info_index, outer_class_info_index,
   193   // inner_name_index, inner_class_access_flags] for the InnerClasses
   194   // attribute. If the EnclosingMethod attribute exists, it occupies the
   195   // last two shorts [class_index, method_index] of the array. If only
   196   // the InnerClasses attribute exists, the _inner_classes array length is
   197   // number_of_inner_classes * 4. If the class has both InnerClasses
   198   // and EnclosingMethod attributes the _inner_classes array length is
   199   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
   200   Array<jushort>* _inner_classes;
   202   // Name of source file containing this klass, NULL if not specified.
   203   Symbol*         _source_file_name;
   204   // the source debug extension for this klass, NULL if not specified.
   205   // Specified as UTF-8 string without terminating zero byte in the classfile,
   206   // it is stored in the instanceklass as a NULL-terminated UTF-8 string
   207   char*           _source_debug_extension;
   208   // Generic signature, or null if none.
   209   Symbol*         _generic_signature;
   210   // Array name derived from this class which needs unreferencing
   211   // if this class is unloaded.
   212   Symbol*         _array_name;
   214   // Number of heapOopSize words used by non-static fields in this klass
   215   // (including inherited fields but after header_size()).
   216   int             _nonstatic_field_size;
   217   int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
   218   u2              _static_oop_field_count;// number of static oop fields in this klass
   219   u2              _java_fields_count;    // The number of declared Java fields
   220   int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
   222   bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
   223   enum {
   224     _misc_rewritten            = 1 << 0, // methods rewritten.
   225     _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
   226     _misc_should_verify_class  = 1 << 2, // allow caching of preverification
   227     _misc_is_anonymous         = 1 << 3  // has embedded _inner_classes field
   228   };
   229   u2              _misc_flags;
   230   u2              _minor_version;        // minor version number of class file
   231   u2              _major_version;        // major version number of class file
   232   Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
   233   int             _vtable_len;           // length of Java vtable (in words)
   234   int             _itable_len;           // length of Java itable (in words)
   235   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
   236   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
   237   jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
   238   int*            _methods_cached_itable_indices;  // itable_index cache for JNI invoke corresponding to methods idnum, or NULL
   239   nmethodBucket*  _dependencies;         // list of dependent nmethods
   240   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
   241   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
   242   // Array of interesting part(s) of the previous version(s) of this
   243   // InstanceKlass. See PreviousVersionWalker below.
   244   GrowableArray<PreviousVersionNode *>* _previous_versions;
   245   // JVMTI fields can be moved to their own structure - see 6315920
   246   unsigned char * _cached_class_file_bytes;       // JVMTI: cached class file, before retransformable agent modified it in CFLH
   247   jint            _cached_class_file_len;         // JVMTI: length of above
   248   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
   250   // true if class, superclass, or implemented interfaces have default methods
   251   bool            _has_default_methods;
   253   volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
   254   // Method array.
   255   Array<Method*>* _methods;
   256   // Interface (Klass*s) this class declares locally to implement.
   257   Array<Klass*>* _local_interfaces;
   258   // Interface (Klass*s) this class implements transitively.
   259   Array<Klass*>* _transitive_interfaces;
   260   // Int array containing the original order of method in the class file (for JVMTI).
   261   Array<int>*     _method_ordering;
   262   // Instance and static variable information, starts with 6-tuples of shorts
   263   // [access, name index, sig index, initval index, low_offset, high_offset]
   264   // for all fields, followed by the generic signature data at the end of
   265   // the array. Only fields with generic signature attributes have the generic
   266   // signature data set in the array. The fields array looks like following:
   267   //
   268   // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
   269   // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
   270   //      ...
   271   // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
   272   //     [generic signature index]
   273   //     [generic signature index]
   274   //     ...
   275   Array<u2>*      _fields;
   277   // Class states are defined as ClassState (see above).
   278   // Place the _init_state here to utilize the unused 2-byte after
   279   // _idnum_allocated_count.
   280   u1              _init_state;                    // state of class
   282   u1              _reference_type;                // reference type
   284   // embedded Java vtable follows here
   285   // embedded Java itables follows here
   286   // embedded static fields follows here
   287   // embedded nonstatic oop-map blocks follows here
   288   // embedded implementor of this interface follows here
   289   //   The embedded implementor only exists if the current klass is an
   290   //   iterface. The possible values of the implementor fall into following
   291   //   three cases:
   292   //     NULL: no implementor.
   293   //     A Klass* that's not itself: one implementor.
   294   //     Itsef: more than one implementors.
   295   // embedded host klass follows here
   296   //   The embedded host klass only exists in an anonymous class for
   297   //   dynamic language support (JSR 292 enabled). The host class grants
   298   //   its access privileges to this class also. The host class is either
   299   //   named, or a previously loaded anonymous class. A non-anonymous class
   300   //   or an anonymous class loaded through normal classloading does not
   301   //   have this embedded field.
   302   //
   304   friend class SystemDictionary;
   306  public:
   307   bool has_nonstatic_fields() const        {
   308     return (_misc_flags & _misc_has_nonstatic_fields) != 0;
   309   }
   310   void set_has_nonstatic_fields(bool b)    {
   311     if (b) {
   312       _misc_flags |= _misc_has_nonstatic_fields;
   313     } else {
   314       _misc_flags &= ~_misc_has_nonstatic_fields;
   315     }
   316   }
   318   // field sizes
   319   int nonstatic_field_size() const         { return _nonstatic_field_size; }
   320   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
   322   int static_field_size() const            { return _static_field_size; }
   323   void set_static_field_size(int size)     { _static_field_size = size; }
   325   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
   326   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
   328   // Java vtable
   329   int  vtable_length() const               { return _vtable_len; }
   330   void set_vtable_length(int len)          { _vtable_len = len; }
   332   // Java itable
   333   int  itable_length() const               { return _itable_len; }
   334   void set_itable_length(int len)          { _itable_len = len; }
   336   // array klasses
   337   Klass* array_klasses() const             { return _array_klasses; }
   338   void set_array_klasses(Klass* k)         { _array_klasses = k; }
   340   // methods
   341   Array<Method*>* methods() const          { return _methods; }
   342   void set_methods(Array<Method*>* a)      { _methods = a; }
   343   Method* method_with_idnum(int idnum);
   345   // method ordering
   346   Array<int>* method_ordering() const     { return _method_ordering; }
   347   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
   349   // interfaces
   350   Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
   351   void set_local_interfaces(Array<Klass*>* a)      {
   352     guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
   353     _local_interfaces = a; }
   354   Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
   355   void set_transitive_interfaces(Array<Klass*>* a) {
   356     guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
   357     _transitive_interfaces = a; }
   359  private:
   360   friend class fieldDescriptor;
   361   FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
   363  public:
   364   int     field_offset      (int index) const { return field(index)->offset(); }
   365   int     field_access_flags(int index) const { return field(index)->access_flags(); }
   366   Symbol* field_name        (int index) const { return field(index)->name(constants()); }
   367   Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
   369   // Number of Java declared fields
   370   int java_fields_count() const           { return (int)_java_fields_count; }
   372   Array<u2>* fields() const            { return _fields; }
   374   void set_fields(Array<u2>* f, u2 java_fields_count) {
   375     guarantee(_fields == NULL || f == NULL, "Just checking");
   376     _fields =  f;
   377     _java_fields_count = java_fields_count;
   378   }
   380   // inner classes
   381   Array<u2>* inner_classes() const       { return _inner_classes; }
   382   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
   384   enum InnerClassAttributeOffset {
   385     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
   386     inner_class_inner_class_info_offset = 0,
   387     inner_class_outer_class_info_offset = 1,
   388     inner_class_inner_name_offset = 2,
   389     inner_class_access_flags_offset = 3,
   390     inner_class_next_offset = 4
   391   };
   393   enum EnclosingMethodAttributeOffset {
   394     enclosing_method_class_index_offset = 0,
   395     enclosing_method_method_index_offset = 1,
   396     enclosing_method_attribute_size = 2
   397   };
   399   // method override check
   400   bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
   402   // package
   403   bool is_same_class_package(Klass* class2);
   404   bool is_same_class_package(oop classloader2, Symbol* classname2);
   405   static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
   407   // find an enclosing class (defined where original code was, in jvm.cpp!)
   408   Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
   409     instanceKlassHandle self(THREAD, this);
   410     return compute_enclosing_class_impl(self, inner_is_member, THREAD);
   411   }
   412   static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
   413                                                bool* inner_is_member, TRAPS);
   415   // tell if two classes have the same enclosing class (at package level)
   416   bool is_same_package_member(Klass* class2, TRAPS) {
   417     instanceKlassHandle self(THREAD, this);
   418     return is_same_package_member_impl(self, class2, THREAD);
   419   }
   420   static bool is_same_package_member_impl(instanceKlassHandle self,
   421                                           Klass* class2, TRAPS);
   423   // initialization state
   424   bool is_loaded() const                   { return _init_state >= loaded; }
   425   bool is_linked() const                   { return _init_state >= linked; }
   426   bool is_initialized() const              { return _init_state == fully_initialized; }
   427   bool is_not_initialized() const          { return _init_state <  being_initialized; }
   428   bool is_being_initialized() const        { return _init_state == being_initialized; }
   429   bool is_in_error_state() const           { return _init_state == initialization_error; }
   430   bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
   431   ClassState  init_state()                 { return (ClassState)_init_state; }
   432   bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
   434   // defineClass specified verification
   435   bool should_verify_class() const         {
   436     return (_misc_flags & _misc_should_verify_class) != 0;
   437   }
   438   void set_should_verify_class(bool value) {
   439     if (value) {
   440       _misc_flags |= _misc_should_verify_class;
   441     } else {
   442       _misc_flags &= ~_misc_should_verify_class;
   443     }
   444   }
   446   // marking
   447   bool is_marked_dependent() const         { return _is_marked_dependent; }
   448   void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
   450   // initialization (virtuals from Klass)
   451   bool should_be_initialized() const;  // means that initialize should be called
   452   void initialize(TRAPS);
   453   void link_class(TRAPS);
   454   bool link_class_or_fail(TRAPS); // returns false on failure
   455   void unlink_class();
   456   void rewrite_class(TRAPS);
   457   void relocate_and_link_methods(TRAPS);
   458   Method* class_initializer();
   460   // set the class to initialized if no static initializer is present
   461   void eager_initialize(Thread *thread);
   463   // reference type
   464   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
   465   void set_reference_type(ReferenceType t) {
   466     assert(t == (u1)t, "overflow");
   467     _reference_type = (u1)t;
   468   }
   470   static ByteSize reference_type_offset() { return in_ByteSize(offset_of(InstanceKlass, _reference_type)); }
   472   // find local field, returns true if found
   473   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
   474   // find field in direct superinterfaces, returns the interface in which the field is defined
   475   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
   476   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
   477   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
   478   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
   479   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
   481   // find a non-static or static field given its offset within the class.
   482   bool contains_field_offset(int offset) {
   483     return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());
   484   }
   486   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
   487   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
   489   // find a local method (returns NULL if not found)
   490   Method* find_method(Symbol* name, Symbol* signature) const;
   491   static Method* find_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
   493   // lookup operation (returns NULL if not found)
   494   Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
   496   // lookup a method in all the interfaces that this class implements
   497   // (returns NULL if not found)
   498   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;
   500   // Find method indices by name.  If a method with the specified name is
   501   // found the index to the first method is returned, and 'end' is filled in
   502   // with the index of first non-name-matching method.  If no method is found
   503   // -1 is returned.
   504   int find_method_by_name(Symbol* name, int* end);
   505   static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
   507   // constant pool
   508   ConstantPool* constants() const        { return _constants; }
   509   void set_constants(ConstantPool* c)    { _constants = c; }
   511   // protection domain
   512   oop protection_domain()                  { return _protection_domain; }
   513   void set_protection_domain(oop pd)       { klass_oop_store(&_protection_domain, pd); }
   515   // host class
   516   Klass* host_klass() const              {
   517     Klass** hk = (Klass**)adr_host_klass();
   518     if (hk == NULL) {
   519       return NULL;
   520     } else {
   521       return *hk;
   522     }
   523   }
   524   void set_host_klass(Klass* host)            {
   525     assert(is_anonymous(), "not anonymous");
   526     Klass** addr = (Klass**)adr_host_klass();
   527     assert(addr != NULL, "no reversed space");
   528     *addr = host;
   529   }
   530   bool is_anonymous() const                {
   531     return (_misc_flags & _misc_is_anonymous) != 0;
   532   }
   533   void set_is_anonymous(bool value)        {
   534     if (value) {
   535       _misc_flags |= _misc_is_anonymous;
   536     } else {
   537       _misc_flags &= ~_misc_is_anonymous;
   538     }
   539   }
   541   // signers
   542   objArrayOop signers() const              { return _signers; }
   543   void set_signers(objArrayOop s)          { klass_oop_store((oop*)&_signers, s); }
   545   // source file name
   546   Symbol* source_file_name() const         { return _source_file_name; }
   547   void set_source_file_name(Symbol* n);
   549   // minor and major version numbers of class file
   550   u2 minor_version() const                 { return _minor_version; }
   551   void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
   552   u2 major_version() const                 { return _major_version; }
   553   void set_major_version(u2 major_version) { _major_version = major_version; }
   555   // source debug extension
   556   char* source_debug_extension() const     { return _source_debug_extension; }
   557   void set_source_debug_extension(char* array, int length);
   559   // symbol unloading support (refcount already added)
   560   Symbol* array_name()                     { return _array_name; }
   561   void set_array_name(Symbol* name)        { assert(_array_name == NULL, "name already created"); _array_name = name; }
   563   // nonstatic oop-map blocks
   564   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
   565     return oop_map_count * OopMapBlock::size_in_words();
   566   }
   567   unsigned int nonstatic_oop_map_count() const {
   568     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
   569   }
   570   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
   571   void set_nonstatic_oop_map_size(int words) {
   572     _nonstatic_oop_map_size = words;
   573   }
   575   // RedefineClasses() support for previous versions:
   576   void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
   577          int emcp_method_count);
   578   // If the _previous_versions array is non-NULL, then this klass
   579   // has been redefined at least once even if we aren't currently
   580   // tracking a previous version.
   581   bool has_been_redefined() const { return _previous_versions != NULL; }
   582   bool has_previous_version() const;
   583   void init_previous_versions() {
   584     _previous_versions = NULL;
   585   }
   586   GrowableArray<PreviousVersionNode *>* previous_versions() const {
   587     return _previous_versions;
   588   }
   590   static void purge_previous_versions(InstanceKlass* ik);
   592   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
   593   void set_cached_class_file(unsigned char *class_file_bytes,
   594                              jint class_file_len)     { _cached_class_file_len = class_file_len;
   595                                                         _cached_class_file_bytes = class_file_bytes; }
   596   jint get_cached_class_file_len()                    { return _cached_class_file_len; }
   597   unsigned char * get_cached_class_file_bytes()       { return _cached_class_file_bytes; }
   599   // JVMTI: Support for caching of field indices, types, and offsets
   600   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
   601     _jvmti_cached_class_field_map = descriptor;
   602   }
   603   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
   604     return _jvmti_cached_class_field_map;
   605   }
   607   bool has_default_methods() const { return _has_default_methods; }
   608   void set_has_default_methods(bool b) { _has_default_methods = b; }
   610   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
   611   inline u2 next_method_idnum();
   612   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
   614   // generics support
   615   Symbol* generic_signature() const                   { return _generic_signature; }
   616   void set_generic_signature(Symbol* sig)             { _generic_signature = sig; }
   618   u2 enclosing_method_data(int offset);
   619   u2 enclosing_method_class_index() {
   620     return enclosing_method_data(enclosing_method_class_index_offset);
   621   }
   622   u2 enclosing_method_method_index() {
   623     return enclosing_method_data(enclosing_method_method_index_offset);
   624   }
   625   void set_enclosing_method_indices(u2 class_index,
   626                                     u2 method_index);
   628   // jmethodID support
   629   static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
   630                      methodHandle method_h);
   631   static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
   632                      size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
   633                      jmethodID* to_dealloc_id_p,
   634                      jmethodID** to_dealloc_jmeths_p);
   635   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
   636                 size_t *length_p, jmethodID* id_p);
   637   jmethodID jmethod_id_or_null(Method* method);
   639   // cached itable index support
   640   void set_cached_itable_index(size_t idnum, int index);
   641   int cached_itable_index(size_t idnum);
   643   // annotations support
   644   Annotations* annotations() const          { return _annotations; }
   645   void set_annotations(Annotations* anno)   { _annotations = anno; }
   646   AnnotationArray* class_annotations() const {
   647     if (annotations() == NULL) return NULL;
   648     return annotations()->class_annotations();
   649   }
   650   Array<AnnotationArray*>* fields_annotations() const {
   651     if (annotations() == NULL) return NULL;
   652     return annotations()->fields_annotations();
   653   }
   655   // allocation
   656   instanceOop allocate_instance(TRAPS);
   658   // additional member function to return a handle
   659   instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
   661   objArrayOop allocate_objArray(int n, int length, TRAPS);
   662   // Helper function
   663   static instanceOop register_finalizer(instanceOop i, TRAPS);
   665   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
   666   // if not, throw either an Error or an Exception.
   667   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
   669   // initialization
   670   void call_class_initializer(TRAPS);
   671   void set_initialization_state_and_notify(ClassState state, TRAPS);
   673   // OopMapCache support
   674   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
   675   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
   676   void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
   678   // JNI identifier support (for static fields - for jni performance)
   679   JNIid* jni_ids()                               { return _jni_ids; }
   680   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
   681   JNIid* jni_id_for(int offset);
   683   // maintenance of deoptimization dependencies
   684   int mark_dependent_nmethods(DepChange& changes);
   685   void add_dependent_nmethod(nmethod* nm);
   686   void remove_dependent_nmethod(nmethod* nm);
   688   // On-stack replacement support
   689   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
   690   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
   691   void add_osr_nmethod(nmethod* n);
   692   void remove_osr_nmethod(nmethod* n);
   693   nmethod* lookup_osr_nmethod(Method* const m, int bci, int level, bool match_level) const;
   695   // Breakpoint support (see methods on Method* for details)
   696   BreakpointInfo* breakpoints() const       { return _breakpoints; };
   697   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
   699   // support for stub routines
   700   static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
   701   TRACE_DEFINE_OFFSET;
   702   static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
   704   // subclass/subinterface checks
   705   bool implements_interface(Klass* k) const;
   707   // Access to the implementor of an interface.
   708   Klass* implementor() const
   709   {
   710     Klass** k = adr_implementor();
   711     if (k == NULL) {
   712       return NULL;
   713     } else {
   714       return *k;
   715     }
   716   }
   718   void set_implementor(Klass* k) {
   719     assert(is_interface(), "not interface");
   720     Klass** addr = adr_implementor();
   721     *addr = k;
   722   }
   724   int  nof_implementors() const       {
   725     Klass* k = implementor();
   726     if (k == NULL) {
   727       return 0;
   728     } else if (k != this) {
   729       return 1;
   730     } else {
   731       return 2;
   732     }
   733   }
   735   void add_implementor(Klass* k);  // k is a new class that implements this interface
   736   void init_implementor();           // initialize
   738   // link this class into the implementors list of every interface it implements
   739   void process_interfaces(Thread *thread);
   741   // virtual operations from Klass
   742   bool is_leaf_class() const               { return _subklass == NULL; }
   743   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
   744   bool compute_is_subtype_of(Klass* k);
   745   bool can_be_primary_super_slow() const;
   746   int oop_size(oop obj)  const             { return size_helper(); }
   747   bool oop_is_instance_slow() const        { return true; }
   749   // Iterators
   750   void do_local_static_fields(FieldClosure* cl);
   751   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
   752   void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);
   754   void methods_do(void f(Method* method));
   755   void array_klasses_do(void f(Klass* k));
   756   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
   757   void with_array_klasses_do(void f(Klass* k));
   758   bool super_types_do(SuperTypeClosure* blk);
   760   // Casting from Klass*
   761   static InstanceKlass* cast(Klass* k) {
   762     assert(k->is_klass(), "must be");
   763     assert(k->oop_is_instance(), "cast to InstanceKlass");
   764     return (InstanceKlass*) k;
   765   }
   767   InstanceKlass* java_super() const {
   768     return (super() == NULL) ? NULL : cast(super());
   769   }
   771   // Sizing (in words)
   772   static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
   773   static int size(int vtable_length, int itable_length,
   774                   int nonstatic_oop_map_size,
   775                   bool is_interface, bool is_anonymous) {
   776     return align_object_size(header_size() +
   777            align_object_offset(vtable_length) +
   778            align_object_offset(itable_length) +
   779            ((is_interface || is_anonymous) ?
   780              align_object_offset(nonstatic_oop_map_size) :
   781              nonstatic_oop_map_size) +
   782            (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
   783            (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
   784   }
   785   int size() const                    { return size(vtable_length(),
   786                                                itable_length(),
   787                                                nonstatic_oop_map_size(),
   788                                                is_interface(),
   789                                                is_anonymous());
   790   }
   792   static int vtable_start_offset()    { return header_size(); }
   793   static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
   795   intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
   796   intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
   797   int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
   799   intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
   801   address static_field_addr(int offset);
   803   OopMapBlock* start_of_nonstatic_oop_maps() const {
   804     return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
   805   }
   807   Klass** adr_implementor() const {
   808     if (is_interface()) {
   809       return (Klass**)(start_of_nonstatic_oop_maps() +
   810                     nonstatic_oop_map_count());
   811     } else {
   812       return NULL;
   813     }
   814   };
   816   Klass** adr_host_klass() const {
   817     if (is_anonymous()) {
   818       Klass** adr_impl = adr_implementor();
   819       if (adr_impl != NULL) {
   820         return adr_impl + 1;
   821       } else {
   822         return (Klass**)(start_of_nonstatic_oop_maps() +
   823                       nonstatic_oop_map_count());
   824       }
   825     } else {
   826       return NULL;
   827     }
   828   }
   830   // Allocation profiling support
   831   juint alloc_size() const            { return _alloc_count * size_helper(); }
   832   void set_alloc_size(juint n)        {}
   834   // Use this to return the size of an instance in heap words:
   835   int size_helper() const {
   836     return layout_helper_to_size_helper(layout_helper());
   837   }
   839   // This bit is initialized in classFileParser.cpp.
   840   // It is false under any of the following conditions:
   841   //  - the class is abstract (including any interface)
   842   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
   843   //  - the class size is larger than FastAllocateSizeLimit
   844   //  - the class is java/lang/Class, which cannot be allocated directly
   845   bool can_be_fastpath_allocated() const {
   846     return !layout_helper_needs_slow_path(layout_helper());
   847   }
   849   // Java vtable/itable
   850   klassVtable* vtable() const;        // return new klassVtable wrapper
   851   inline Method* method_at_vtable(int index);
   852   klassItable* itable() const;        // return new klassItable wrapper
   853   Method* method_at_itable(Klass* holder, int index, TRAPS);
   855   // Garbage collection
   856   virtual void oops_do(OopClosure* cl);
   858   void oop_follow_contents(oop obj);
   859   int  oop_adjust_pointers(oop obj);
   861   void clean_implementors_list(BoolObjectClosure* is_alive);
   862   void clean_method_data(BoolObjectClosure* is_alive);
   864   // Explicit metaspace deallocation of fields
   865   // For RedefineClasses, we need to deallocate instanceKlasses
   866   void deallocate_contents(ClassLoaderData* loader_data);
   868   // The constant pool is on stack if any of the methods are executing or
   869   // referenced by handles.
   870   bool on_stack() const { return _constants->on_stack(); }
   872   void release_C_heap_structures();
   874   // Parallel Scavenge and Parallel Old
   875   PARALLEL_GC_DECLS
   877   // Naming
   878   const char* signature_name() const;
   880   // Iterators
   881   int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
   882     return oop_oop_iterate_v(obj, blk);
   883   }
   885   int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
   886     return oop_oop_iterate_v_m(obj, blk, mr);
   887   }
   889 #define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
   890   int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
   891   int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
   892                                       MemRegion mr);
   894   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
   895   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
   897 #ifndef SERIALGC
   898 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
   899   int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
   901   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
   902   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
   903 #endif // !SERIALGC
   905   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
   906 private:
   907   // initialization state
   908 #ifdef ASSERT
   909   void set_init_state(ClassState state);
   910 #else
   911   void set_init_state(ClassState state) { _init_state = (u1)state; }
   912 #endif
   913   void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
   914   void set_init_thread(Thread *thread)  { _init_thread = thread; }
   916   // The RedefineClasses() API can cause new method idnums to be needed
   917   // which will cause the caches to grow. Safety requires different
   918   // cache management logic if the caches can grow instead of just
   919   // going from NULL to non-NULL.
   920   bool idnum_can_increment() const      { return has_been_redefined(); }
   921   jmethodID* methods_jmethod_ids_acquire() const
   922          { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
   923   void release_set_methods_jmethod_ids(jmethodID* jmeths)
   924          { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
   926   int* methods_cached_itable_indices_acquire() const
   927          { return (int*)OrderAccess::load_ptr_acquire(&_methods_cached_itable_indices); }
   928   void release_set_methods_cached_itable_indices(int* indices)
   929          { OrderAccess::release_store_ptr(&_methods_cached_itable_indices, indices); }
   931   // Lock during initialization
   932   volatile oop init_lock() const;
   933   void set_init_lock(oop value)      { klass_oop_store(&_init_lock, value); }
   934   void fence_and_clear_init_lock();  // after fully_initialized
   936   // Offsets for memory management
   937   oop* adr_protection_domain() const { return (oop*)&this->_protection_domain;}
   938   oop* adr_signers() const           { return (oop*)&this->_signers;}
   939   oop* adr_init_lock() const         { return (oop*)&this->_init_lock;}
   941   // Static methods that are used to implement member methods where an exposed this pointer
   942   // is needed due to possible GCs
   943   static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
   944   static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
   945   static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
   946   static void eager_initialize_impl                     (instanceKlassHandle this_oop);
   947   static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
   948   static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
   949   static Klass* array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
   950   static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
   951   /* jni_id_for_impl for jfieldID only */
   952   static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);
   954   // Returns the array class for the n'th dimension
   955   Klass* array_klass_impl(bool or_null, int n, TRAPS);
   957   // Returns the array class with this class as element type
   958   Klass* array_klass_impl(bool or_null, TRAPS);
   960 public:
   961   // CDS support - remove and restore oops from metadata. Oops are not shared.
   962   virtual void remove_unshareable_info();
   963   virtual void restore_unshareable_info(TRAPS);
   965   // jvm support
   966   jint compute_modifier_flags(TRAPS) const;
   968 public:
   969   // JVMTI support
   970   jint jvmti_class_status() const;
   972  public:
   973   // Printing
   974 #ifndef PRODUCT
   975   void print_on(outputStream* st) const;
   976 #endif
   977   void print_value_on(outputStream* st) const;
   979   void oop_print_value_on(oop obj, outputStream* st);
   981 #ifndef PRODUCT
   982   void oop_print_on      (oop obj, outputStream* st);
   984   void print_dependent_nmethods(bool verbose = false);
   985   bool is_dependent_nmethod(nmethod* nm);
   986 #endif
   988   const char* internal_name() const;
   990   // Verification
   991   void verify_on(outputStream* st);
   993   void oop_verify_on(oop obj, outputStream* st);
   994 };
   996 inline Method* InstanceKlass::method_at_vtable(int index)  {
   997 #ifndef PRODUCT
   998   assert(index >= 0, "valid vtable index");
   999   if (DebugVtables) {
  1000     verify_vtable_index(index);
  1002 #endif
  1003   vtableEntry* ve = (vtableEntry*)start_of_vtable();
  1004   return ve[index].method();
  1007 // for adding methods
  1008 // UNSET_IDNUM return means no more ids available
  1009 inline u2 InstanceKlass::next_method_idnum() {
  1010   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
  1011     return ConstMethod::UNSET_IDNUM; // no more ids available
  1012   } else {
  1013     return _idnum_allocated_count++;
  1018 /* JNIid class for jfieldIDs only */
  1019 class JNIid: public CHeapObj<mtClass> {
  1020   friend class VMStructs;
  1021  private:
  1022   Klass*             _holder;
  1023   JNIid*             _next;
  1024   int                _offset;
  1025 #ifdef ASSERT
  1026   bool               _is_static_field_id;
  1027 #endif
  1029  public:
  1030   // Accessors
  1031   Klass* holder() const           { return _holder; }
  1032   int offset() const              { return _offset; }
  1033   JNIid* next()                   { return _next; }
  1034   // Constructor
  1035   JNIid(Klass* holder, int offset, JNIid* next);
  1036   // Identifier lookup
  1037   JNIid* find(int offset);
  1039   bool find_local_field(fieldDescriptor* fd) {
  1040     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
  1043   static void deallocate(JNIid* id);
  1044   // Debugging
  1045 #ifdef ASSERT
  1046   bool is_static_field_id() const { return _is_static_field_id; }
  1047   void set_is_static_field_id()   { _is_static_field_id = true; }
  1048 #endif
  1049   void verify(Klass* holder);
  1050 };
  1053 // If breakpoints are more numerous than just JVMTI breakpoints,
  1054 // consider compressing this data structure.
  1055 // It is currently a simple linked list defined in method.hpp.
  1057 class BreakpointInfo;
  1060 // A collection point for interesting information about the previous
  1061 // version(s) of an InstanceKlass. This class uses weak references to
  1062 // the information so that the information may be collected as needed
  1063 // by the system. If the information is shared, then a regular
  1064 // reference must be used because a weak reference would be seen as
  1065 // collectible. A GrowableArray of PreviousVersionNodes is attached
  1066 // to the InstanceKlass as needed. See PreviousVersionWalker below.
  1067 class PreviousVersionNode : public CHeapObj<mtClass> {
  1068  private:
  1069   // A shared ConstantPool is never collected so we'll always have
  1070   // a reference to it so we can update items in the cache. We'll
  1071   // have a weak reference to a non-shared ConstantPool until all
  1072   // of the methods (EMCP or obsolete) have been collected; the
  1073   // non-shared ConstantPool becomes collectible at that point.
  1074   ConstantPool*    _prev_constant_pool;  // regular or weak reference
  1075   bool    _prev_cp_is_weak;     // true if not a shared ConstantPool
  1077   // If the previous version of the InstanceKlass doesn't have any
  1078   // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
  1079   // EMCP methods have been collected, then _prev_EMCP_methods can
  1080   // have a length of zero.
  1081   GrowableArray<Method*>* _prev_EMCP_methods;
  1083 public:
  1084   PreviousVersionNode(ConstantPool* prev_constant_pool, bool prev_cp_is_weak,
  1085     GrowableArray<Method*>* prev_EMCP_methods);
  1086   ~PreviousVersionNode();
  1087   ConstantPool* prev_constant_pool() const {
  1088     return _prev_constant_pool;
  1090   GrowableArray<Method*>* prev_EMCP_methods() const {
  1091     return _prev_EMCP_methods;
  1093 };
  1096 // A Handle-ized version of PreviousVersionNode.
  1097 class PreviousVersionInfo : public ResourceObj {
  1098  private:
  1099   constantPoolHandle   _prev_constant_pool_handle;
  1100   // If the previous version of the InstanceKlass doesn't have any
  1101   // EMCP methods, then _prev_EMCP_methods will be NULL. Since the
  1102   // methods cannot be collected while we hold a handle,
  1103   // _prev_EMCP_methods should never have a length of zero.
  1104   GrowableArray<methodHandle>* _prev_EMCP_method_handles;
  1106 public:
  1107   PreviousVersionInfo(PreviousVersionNode *pv_node);
  1108   ~PreviousVersionInfo();
  1109   constantPoolHandle prev_constant_pool_handle() const {
  1110     return _prev_constant_pool_handle;
  1112   GrowableArray<methodHandle>* prev_EMCP_method_handles() const {
  1113     return _prev_EMCP_method_handles;
  1115 };
  1118 // Helper object for walking previous versions. This helper cleans up
  1119 // the Handles that it allocates when the helper object is destroyed.
  1120 // The PreviousVersionInfo object returned by next_previous_version()
  1121 // is only valid until a subsequent call to next_previous_version() or
  1122 // the helper object is destroyed.
  1123 class PreviousVersionWalker : public StackObj {
  1124  private:
  1125   GrowableArray<PreviousVersionNode *>* _previous_versions;
  1126   int                                   _current_index;
  1127   // Fields for cleaning up when we are done walking the previous versions:
  1128   // A HandleMark for the PreviousVersionInfo handles:
  1129   HandleMark                            _hm;
  1131   // It would be nice to have a ResourceMark field in this helper also,
  1132   // but the ResourceMark code says to be careful to delete handles held
  1133   // in GrowableArrays _before_ deleting the GrowableArray. Since we
  1134   // can't guarantee the order in which the fields are destroyed, we
  1135   // have to let the creator of the PreviousVersionWalker object do
  1136   // the right thing. Also, adding a ResourceMark here causes an
  1137   // include loop.
  1139   // A pointer to the current info object so we can handle the deletes.
  1140   PreviousVersionInfo *                 _current_p;
  1142  public:
  1143   PreviousVersionWalker(InstanceKlass *ik);
  1144   ~PreviousVersionWalker();
  1146   // Return the interesting information for the next previous version
  1147   // of the klass. Returns NULL if there are no more previous versions.
  1148   PreviousVersionInfo* next_previous_version();
  1149 };
  1152 //
  1153 // nmethodBucket is used to record dependent nmethods for
  1154 // deoptimization.  nmethod dependencies are actually <klass, method>
  1155 // pairs but we really only care about the klass part for purposes of
  1156 // finding nmethods which might need to be deoptimized.  Instead of
  1157 // recording the method, a count of how many times a particular nmethod
  1158 // was recorded is kept.  This ensures that any recording errors are
  1159 // noticed since an nmethod should be removed as many times are it's
  1160 // added.
  1161 //
  1162 class nmethodBucket: public CHeapObj<mtClass> {
  1163   friend class VMStructs;
  1164  private:
  1165   nmethod*       _nmethod;
  1166   int            _count;
  1167   nmethodBucket* _next;
  1169  public:
  1170   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
  1171     _nmethod = nmethod;
  1172     _next = next;
  1173     _count = 1;
  1175   int count()                             { return _count; }
  1176   int increment()                         { _count += 1; return _count; }
  1177   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
  1178   nmethodBucket* next()                   { return _next; }
  1179   void set_next(nmethodBucket* b)         { _next = b; }
  1180   nmethod* get_nmethod()                  { return _nmethod; }
  1181 };
  1183 // An iterator that's used to access the inner classes indices in the
  1184 // InstanceKlass::_inner_classes array.
  1185 class InnerClassesIterator : public StackObj {
  1186  private:
  1187   Array<jushort>* _inner_classes;
  1188   int _length;
  1189   int _idx;
  1190  public:
  1192   InnerClassesIterator(instanceKlassHandle k) {
  1193     _inner_classes = k->inner_classes();
  1194     if (k->inner_classes() != NULL) {
  1195       _length = _inner_classes->length();
  1196       // The inner class array's length should be the multiple of
  1197       // inner_class_next_offset if it only contains the InnerClasses
  1198       // attribute data, or it should be
  1199       // n*inner_class_next_offset+enclosing_method_attribute_size
  1200       // if it also contains the EnclosingMethod data.
  1201       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
  1202               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
  1203              "just checking");
  1204       // Remove the enclosing_method portion if exists.
  1205       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
  1206         _length -= InstanceKlass::enclosing_method_attribute_size;
  1208     } else {
  1209       _length = 0;
  1211     _idx = 0;
  1214   int length() const {
  1215     return _length;
  1218   void next() {
  1219     _idx += InstanceKlass::inner_class_next_offset;
  1222   bool done() const {
  1223     return (_idx >= _length);
  1226   u2 inner_class_info_index() const {
  1227     return _inner_classes->at(
  1228                _idx + InstanceKlass::inner_class_inner_class_info_offset);
  1231   void set_inner_class_info_index(u2 index) {
  1232     _inner_classes->at_put(
  1233                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
  1236   u2 outer_class_info_index() const {
  1237     return _inner_classes->at(
  1238                _idx + InstanceKlass::inner_class_outer_class_info_offset);
  1241   void set_outer_class_info_index(u2 index) {
  1242     _inner_classes->at_put(
  1243                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
  1246   u2 inner_name_index() const {
  1247     return _inner_classes->at(
  1248                _idx + InstanceKlass::inner_class_inner_name_offset);
  1251   void set_inner_name_index(u2 index) {
  1252     _inner_classes->at_put(
  1253                _idx + InstanceKlass::inner_class_inner_name_offset, index);
  1256   u2 inner_access_flags() const {
  1257     return _inner_classes->at(
  1258                _idx + InstanceKlass::inner_class_access_flags_offset);
  1260 };
  1262 #endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP

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