instanceKlass.hpp revision 4074:44c5fcd9cb25
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 */
24
25#ifndef SHARE_VM_OOPS_INSTANCEKLASS_HPP
26#define SHARE_VM_OOPS_INSTANCEKLASS_HPP
27
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/atomic.hpp"
35#include "runtime/handles.hpp"
36#include "runtime/os.hpp"
37#include "utilities/accessFlags.hpp"
38#include "utilities/bitMap.inline.hpp"
39
40// An InstanceKlass is the VM level representation of a Java class.
41// It contains all information needed for at class at execution runtime.
42
43//  InstanceKlass layout:
44//    [C++ vtbl pointer           ] Klass
45//    [subtype cache              ] Klass
46//    [instance size              ] Klass
47//    [java mirror                ] Klass
48//    [super                      ] Klass
49//    [access_flags               ] Klass
50//    [name                       ] Klass
51//    [first subklass             ] Klass
52//    [next sibling               ] Klass
53//    [array klasses              ]
54//    [methods                    ]
55//    [local interfaces           ]
56//    [transitive interfaces      ]
57//    [fields                     ]
58//    [constants                  ]
59//    [class loader               ]
60//    [protection domain          ]
61//    [signers                    ]
62//    [source file name           ]
63//    [inner classes              ]
64//    [static field size          ]
65//    [nonstatic field size       ]
66//    [static oop fields size     ]
67//    [nonstatic oop maps size    ]
68//    [has finalize method        ]
69//    [deoptimization mark bit    ]
70//    [initialization state       ]
71//    [initializing thread        ]
72//    [Java vtable length         ]
73//    [oop map cache (stack maps) ]
74//    [EMBEDDED Java vtable             ] size in words = vtable_len
75//    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
76//      The embedded nonstatic oop-map blocks are short pairs (offset, length)
77//      indicating where oops are located in instances of this klass.
78//    [EMBEDDED implementor of the interface] only exist for interface
79//    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
80
81
82// forward declaration for class -- see below for definition
83class SuperTypeClosure;
84class JNIid;
85class jniIdMapBase;
86class BreakpointInfo;
87class fieldDescriptor;
88class DepChange;
89class nmethodBucket;
90class PreviousVersionNode;
91class JvmtiCachedClassFieldMap;
92
93// This is used in iterators below.
94class FieldClosure: public StackObj {
95public:
96  virtual void do_field(fieldDescriptor* fd) = 0;
97};
98
99#ifndef PRODUCT
100// Print fields.
101// If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
102class FieldPrinter: public FieldClosure {
103   oop _obj;
104   outputStream* _st;
105 public:
106   FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
107   void do_field(fieldDescriptor* fd);
108};
109#endif  // !PRODUCT
110
111// ValueObjs embedded in klass. Describes where oops are located in instances of
112// this klass.
113class OopMapBlock VALUE_OBJ_CLASS_SPEC {
114 public:
115  // Byte offset of the first oop mapped by this block.
116  int offset() const          { return _offset; }
117  void set_offset(int offset) { _offset = offset; }
118
119  // Number of oops in this block.
120  uint count() const         { return _count; }
121  void set_count(uint count) { _count = count; }
122
123  // sizeof(OopMapBlock) in HeapWords.
124  static const int size_in_words() {
125    return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
126      LogHeapWordSize;
127  }
128
129 private:
130  int  _offset;
131  uint _count;
132};
133
134class InstanceKlass: public Klass {
135  friend class VMStructs;
136  friend class ClassFileParser;
137  friend class CompileReplay;
138
139 protected:
140  // Constructor
141  InstanceKlass(int vtable_len,
142                int itable_len,
143                int static_field_size,
144                int nonstatic_oop_map_size,
145                ReferenceType rt,
146                AccessFlags access_flags,
147                bool is_anonymous);
148 public:
149  static Klass* allocate_instance_klass(ClassLoaderData* loader_data,
150                                          int vtable_len,
151                                          int itable_len,
152                                          int static_field_size,
153                                          int nonstatic_oop_map_size,
154                                          ReferenceType rt,
155                                          AccessFlags access_flags,
156                                          Symbol* name,
157                                        Klass* super_klass,
158                                          KlassHandle host_klass,
159                                          TRAPS);
160
161  InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
162
163  // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
164  // of the class loading & initialization procedure, and the use of the states.
165  enum ClassState {
166    allocated,                          // allocated (but not yet linked)
167    loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
168    linked,                             // successfully linked/verified (but not initialized yet)
169    being_initialized,                  // currently running class initializer
170    fully_initialized,                  // initialized (successfull final state)
171    initialization_error                // error happened during initialization
172  };
173
174  static int number_of_instance_classes() { return _total_instanceKlass_count; }
175
176 private:
177  static volatile int _total_instanceKlass_count;
178
179 protected:
180  // Protection domain.
181  oop             _protection_domain;
182  // Class signers.
183  objArrayOop     _signers;
184  // Initialization lock.  Must be one per class and it has to be a VM internal
185  // object so java code cannot lock it (like the mirror)
186  // It has to be an object not a Mutex because it's held through java calls.
187  volatile oop    _init_lock;
188
189  // Annotations for this class
190  Annotations*    _annotations;
191  // Array classes holding elements of this class.
192  Klass*          _array_klasses;
193  // Constant pool for this class.
194  ConstantPool* _constants;
195  // The InnerClasses attribute and EnclosingMethod attribute. The
196  // _inner_classes is an array of shorts. If the class has InnerClasses
197  // attribute, then the _inner_classes array begins with 4-tuples of shorts
198  // [inner_class_info_index, outer_class_info_index,
199  // inner_name_index, inner_class_access_flags] for the InnerClasses
200  // attribute. If the EnclosingMethod attribute exists, it occupies the
201  // last two shorts [class_index, method_index] of the array. If only
202  // the InnerClasses attribute exists, the _inner_classes array length is
203  // number_of_inner_classes * 4. If the class has both InnerClasses
204  // and EnclosingMethod attributes the _inner_classes array length is
205  // number_of_inner_classes * 4 + enclosing_method_attribute_size.
206  Array<jushort>* _inner_classes;
207
208  // Name of source file containing this klass, NULL if not specified.
209  Symbol*         _source_file_name;
210  // the source debug extension for this klass, NULL if not specified.
211  // Specified as UTF-8 string without terminating zero byte in the classfile,
212  // it is stored in the instanceklass as a NULL-terminated UTF-8 string
213  char*           _source_debug_extension;
214  // Generic signature, or null if none.
215  Symbol*         _generic_signature;
216  // Array name derived from this class which needs unreferencing
217  // if this class is unloaded.
218  Symbol*         _array_name;
219
220  // Number of heapOopSize words used by non-static fields in this klass
221  // (including inherited fields but after header_size()).
222  int             _nonstatic_field_size;
223  int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
224  u2              _static_oop_field_count;// number of static oop fields in this klass
225  u2              _java_fields_count;    // The number of declared Java fields
226  int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
227
228  // _is_marked_dependent can be set concurrently, thus cannot be part of the
229  // _misc_flags.
230  bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
231
232  enum {
233    _misc_rewritten            = 1 << 0, // methods rewritten.
234    _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
235    _misc_should_verify_class  = 1 << 2, // allow caching of preverification
236    _misc_is_anonymous         = 1 << 3, // has embedded _inner_classes field
237    _misc_is_contended         = 1 << 4, // marked with contended annotation
238    _misc_has_default_methods  = 1 << 5  // class/superclass/implemented interfaces has default methods
239  };
240  u2              _misc_flags;
241  u2              _minor_version;        // minor version number of class file
242  u2              _major_version;        // major version number of class file
243  Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
244  int             _vtable_len;           // length of Java vtable (in words)
245  int             _itable_len;           // length of Java itable (in words)
246  OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
247  JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
248  jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
249  int*            _methods_cached_itable_indices;  // itable_index cache for JNI invoke corresponding to methods idnum, or NULL
250  nmethodBucket*  _dependencies;         // list of dependent nmethods
251  nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
252  BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
253  // Array of interesting part(s) of the previous version(s) of this
254  // InstanceKlass. See PreviousVersionWalker below.
255  GrowableArray<PreviousVersionNode *>* _previous_versions;
256  // JVMTI fields can be moved to their own structure - see 6315920
257  unsigned char * _cached_class_file_bytes;       // JVMTI: cached class file, before retransformable agent modified it in CFLH
258  jint            _cached_class_file_len;         // JVMTI: length of above
259
260  volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
261
262  // Class states are defined as ClassState (see above).
263  // Place the _init_state here to utilize the unused 2-byte after
264  // _idnum_allocated_count.
265  u1              _init_state;                    // state of class
266  u1              _reference_type;                // reference type
267
268
269  JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
270
271  // Method array.
272  Array<Method*>* _methods;
273  // Interface (Klass*s) this class declares locally to implement.
274  Array<Klass*>* _local_interfaces;
275  // Interface (Klass*s) this class implements transitively.
276  Array<Klass*>* _transitive_interfaces;
277  // Int array containing the original order of method in the class file (for JVMTI).
278  Array<int>*     _method_ordering;
279  // Instance and static variable information, starts with 6-tuples of shorts
280  // [access, name index, sig index, initval index, low_offset, high_offset]
281  // for all fields, followed by the generic signature data at the end of
282  // the array. Only fields with generic signature attributes have the generic
283  // signature data set in the array. The fields array looks like following:
284  //
285  // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
286  // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
287  //      ...
288  // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
289  //     [generic signature index]
290  //     [generic signature index]
291  //     ...
292  Array<u2>*      _fields;
293
294  // embedded Java vtable follows here
295  // embedded Java itables follows here
296  // embedded static fields follows here
297  // embedded nonstatic oop-map blocks follows here
298  // embedded implementor of this interface follows here
299  //   The embedded implementor only exists if the current klass is an
300  //   iterface. The possible values of the implementor fall into following
301  //   three cases:
302  //     NULL: no implementor.
303  //     A Klass* that's not itself: one implementor.
304  //     Itsef: more than one implementors.
305  // embedded host klass follows here
306  //   The embedded host klass only exists in an anonymous class for
307  //   dynamic language support (JSR 292 enabled). The host class grants
308  //   its access privileges to this class also. The host class is either
309  //   named, or a previously loaded anonymous class. A non-anonymous class
310  //   or an anonymous class loaded through normal classloading does not
311  //   have this embedded field.
312  //
313
314  friend class SystemDictionary;
315
316 public:
317  bool has_nonstatic_fields() const        {
318    return (_misc_flags & _misc_has_nonstatic_fields) != 0;
319  }
320  void set_has_nonstatic_fields(bool b)    {
321    if (b) {
322      _misc_flags |= _misc_has_nonstatic_fields;
323    } else {
324      _misc_flags &= ~_misc_has_nonstatic_fields;
325    }
326  }
327
328  // field sizes
329  int nonstatic_field_size() const         { return _nonstatic_field_size; }
330  void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
331
332  int static_field_size() const            { return _static_field_size; }
333  void set_static_field_size(int size)     { _static_field_size = size; }
334
335  int static_oop_field_count() const       { return (int)_static_oop_field_count; }
336  void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
337
338  // Java vtable
339  int  vtable_length() const               { return _vtable_len; }
340  void set_vtable_length(int len)          { _vtable_len = len; }
341
342  // Java itable
343  int  itable_length() const               { return _itable_len; }
344  void set_itable_length(int len)          { _itable_len = len; }
345
346  // array klasses
347  Klass* array_klasses() const             { return _array_klasses; }
348  void set_array_klasses(Klass* k)         { _array_klasses = k; }
349
350  // methods
351  Array<Method*>* methods() const          { return _methods; }
352  void set_methods(Array<Method*>* a)      { _methods = a; }
353  Method* method_with_idnum(int idnum);
354
355  // method ordering
356  Array<int>* method_ordering() const     { return _method_ordering; }
357  void set_method_ordering(Array<int>* m) { _method_ordering = m; }
358
359  // interfaces
360  Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
361  void set_local_interfaces(Array<Klass*>* a)      {
362    guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
363    _local_interfaces = a; }
364  Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
365  void set_transitive_interfaces(Array<Klass*>* a) {
366    guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
367    _transitive_interfaces = a; }
368
369 private:
370  friend class fieldDescriptor;
371  FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
372
373 public:
374  int     field_offset      (int index) const { return field(index)->offset(); }
375  int     field_access_flags(int index) const { return field(index)->access_flags(); }
376  Symbol* field_name        (int index) const { return field(index)->name(constants()); }
377  Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
378
379  // Number of Java declared fields
380  int java_fields_count() const           { return (int)_java_fields_count; }
381
382  Array<u2>* fields() const            { return _fields; }
383
384  void set_fields(Array<u2>* f, u2 java_fields_count) {
385    guarantee(_fields == NULL || f == NULL, "Just checking");
386    _fields =  f;
387    _java_fields_count = java_fields_count;
388  }
389
390  // inner classes
391  Array<u2>* inner_classes() const       { return _inner_classes; }
392  void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
393
394  enum InnerClassAttributeOffset {
395    // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
396    inner_class_inner_class_info_offset = 0,
397    inner_class_outer_class_info_offset = 1,
398    inner_class_inner_name_offset = 2,
399    inner_class_access_flags_offset = 3,
400    inner_class_next_offset = 4
401  };
402
403  enum EnclosingMethodAttributeOffset {
404    enclosing_method_class_index_offset = 0,
405    enclosing_method_method_index_offset = 1,
406    enclosing_method_attribute_size = 2
407  };
408
409  // method override check
410  bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
411
412  // package
413  bool is_same_class_package(Klass* class2);
414  bool is_same_class_package(oop classloader2, Symbol* classname2);
415  static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
416
417  // find an enclosing class (defined where original code was, in jvm.cpp!)
418  Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
419    instanceKlassHandle self(THREAD, this);
420    return compute_enclosing_class_impl(self, inner_is_member, THREAD);
421  }
422  static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
423                                               bool* inner_is_member, TRAPS);
424
425  // tell if two classes have the same enclosing class (at package level)
426  bool is_same_package_member(Klass* class2, TRAPS) {
427    instanceKlassHandle self(THREAD, this);
428    return is_same_package_member_impl(self, class2, THREAD);
429  }
430  static bool is_same_package_member_impl(instanceKlassHandle self,
431                                          Klass* class2, TRAPS);
432
433  // initialization state
434  bool is_loaded() const                   { return _init_state >= loaded; }
435  bool is_linked() const                   { return _init_state >= linked; }
436  bool is_initialized() const              { return _init_state == fully_initialized; }
437  bool is_not_initialized() const          { return _init_state <  being_initialized; }
438  bool is_being_initialized() const        { return _init_state == being_initialized; }
439  bool is_in_error_state() const           { return _init_state == initialization_error; }
440  bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
441  ClassState  init_state()                 { return (ClassState)_init_state; }
442  bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
443
444  // defineClass specified verification
445  bool should_verify_class() const         {
446    return (_misc_flags & _misc_should_verify_class) != 0;
447  }
448  void set_should_verify_class(bool value) {
449    if (value) {
450      _misc_flags |= _misc_should_verify_class;
451    } else {
452      _misc_flags &= ~_misc_should_verify_class;
453    }
454  }
455
456  // marking
457  bool is_marked_dependent() const         { return _is_marked_dependent; }
458  void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
459
460  // initialization (virtuals from Klass)
461  bool should_be_initialized() const;  // means that initialize should be called
462  void initialize(TRAPS);
463  void link_class(TRAPS);
464  bool link_class_or_fail(TRAPS); // returns false on failure
465  void unlink_class();
466  void rewrite_class(TRAPS);
467  void link_methods(TRAPS);
468  Method* class_initializer();
469
470  // set the class to initialized if no static initializer is present
471  void eager_initialize(Thread *thread);
472
473  // reference type
474  ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
475  void set_reference_type(ReferenceType t) {
476    assert(t == (u1)t, "overflow");
477    _reference_type = (u1)t;
478  }
479
480  static ByteSize reference_type_offset() { return in_ByteSize(offset_of(InstanceKlass, _reference_type)); }
481
482  // find local field, returns true if found
483  bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
484  // find field in direct superinterfaces, returns the interface in which the field is defined
485  Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
486  // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
487  Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
488  // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
489  Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
490
491  // find a non-static or static field given its offset within the class.
492  bool contains_field_offset(int offset) {
493    return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());
494  }
495
496  bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
497  bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
498
499  // find a local method (returns NULL if not found)
500  Method* find_method(Symbol* name, Symbol* signature) const;
501  static Method* find_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
502
503  // lookup operation (returns NULL if not found)
504  Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
505
506  // lookup a method in all the interfaces that this class implements
507  // (returns NULL if not found)
508  Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;
509
510  // Find method indices by name.  If a method with the specified name is
511  // found the index to the first method is returned, and 'end' is filled in
512  // with the index of first non-name-matching method.  If no method is found
513  // -1 is returned.
514  int find_method_by_name(Symbol* name, int* end);
515  static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
516
517  // constant pool
518  ConstantPool* constants() const        { return _constants; }
519  void set_constants(ConstantPool* c)    { _constants = c; }
520
521  // protection domain
522  oop protection_domain()                  { return _protection_domain; }
523  void set_protection_domain(oop pd)       { klass_oop_store(&_protection_domain, pd); }
524
525  // host class
526  Klass* host_klass() const              {
527    Klass** hk = (Klass**)adr_host_klass();
528    if (hk == NULL) {
529      return NULL;
530    } else {
531      return *hk;
532    }
533  }
534  void set_host_klass(Klass* host)            {
535    assert(is_anonymous(), "not anonymous");
536    Klass** addr = (Klass**)adr_host_klass();
537    assert(addr != NULL, "no reversed space");
538    *addr = host;
539  }
540  bool is_anonymous() const                {
541    return (_misc_flags & _misc_is_anonymous) != 0;
542  }
543  void set_is_anonymous(bool value)        {
544    if (value) {
545      _misc_flags |= _misc_is_anonymous;
546    } else {
547      _misc_flags &= ~_misc_is_anonymous;
548    }
549  }
550
551  // Oop that keeps the metadata for this class from being unloaded
552  // in places where the metadata is stored in other places, like nmethods
553  oop klass_holder() const {
554    return is_anonymous() ? java_mirror() : class_loader();
555  }
556
557  bool is_contended() const                {
558    return (_misc_flags & _misc_is_contended) != 0;
559  }
560  void set_is_contended(bool value)        {
561    if (value) {
562      _misc_flags |= _misc_is_contended;
563    } else {
564      _misc_flags &= ~_misc_is_contended;
565    }
566  }
567
568  // signers
569  objArrayOop signers() const              { return _signers; }
570  void set_signers(objArrayOop s)          { klass_oop_store((oop*)&_signers, s); }
571
572  // source file name
573  Symbol* source_file_name() const         { return _source_file_name; }
574  void set_source_file_name(Symbol* n);
575
576  // minor and major version numbers of class file
577  u2 minor_version() const                 { return _minor_version; }
578  void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
579  u2 major_version() const                 { return _major_version; }
580  void set_major_version(u2 major_version) { _major_version = major_version; }
581
582  // source debug extension
583  char* source_debug_extension() const     { return _source_debug_extension; }
584  void set_source_debug_extension(char* array, int length);
585
586  // symbol unloading support (refcount already added)
587  Symbol* array_name()                     { return _array_name; }
588  void set_array_name(Symbol* name)        { assert(_array_name == NULL, "name already created"); _array_name = name; }
589
590  // nonstatic oop-map blocks
591  static int nonstatic_oop_map_size(unsigned int oop_map_count) {
592    return oop_map_count * OopMapBlock::size_in_words();
593  }
594  unsigned int nonstatic_oop_map_count() const {
595    return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
596  }
597  int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
598  void set_nonstatic_oop_map_size(int words) {
599    _nonstatic_oop_map_size = words;
600  }
601
602  // RedefineClasses() support for previous versions:
603  void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
604         int emcp_method_count);
605  // If the _previous_versions array is non-NULL, then this klass
606  // has been redefined at least once even if we aren't currently
607  // tracking a previous version.
608  bool has_been_redefined() const { return _previous_versions != NULL; }
609  bool has_previous_version() const;
610  void init_previous_versions() {
611    _previous_versions = NULL;
612  }
613  GrowableArray<PreviousVersionNode *>* previous_versions() const {
614    return _previous_versions;
615  }
616
617  static void purge_previous_versions(InstanceKlass* ik);
618
619  // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
620  void set_cached_class_file(unsigned char *class_file_bytes,
621                             jint class_file_len)     { _cached_class_file_len = class_file_len;
622                                                        _cached_class_file_bytes = class_file_bytes; }
623  jint get_cached_class_file_len()                    { return _cached_class_file_len; }
624  unsigned char * get_cached_class_file_bytes()       { return _cached_class_file_bytes; }
625
626  // JVMTI: Support for caching of field indices, types, and offsets
627  void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
628    _jvmti_cached_class_field_map = descriptor;
629  }
630  JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
631    return _jvmti_cached_class_field_map;
632  }
633
634  bool has_default_methods() const {
635    return (_misc_flags & _misc_has_default_methods) != 0;
636  }
637  void set_has_default_methods(bool b) {
638    if (b) {
639      _misc_flags |= _misc_has_default_methods;
640    } else {
641      _misc_flags &= ~_misc_has_default_methods;
642    }
643  }
644
645  // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
646  inline u2 next_method_idnum();
647  void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
648
649  // generics support
650  Symbol* generic_signature() const                   { return _generic_signature; }
651  void set_generic_signature(Symbol* sig)             { _generic_signature = sig; }
652
653  u2 enclosing_method_data(int offset);
654  u2 enclosing_method_class_index() {
655    return enclosing_method_data(enclosing_method_class_index_offset);
656  }
657  u2 enclosing_method_method_index() {
658    return enclosing_method_data(enclosing_method_method_index_offset);
659  }
660  void set_enclosing_method_indices(u2 class_index,
661                                    u2 method_index);
662
663  // jmethodID support
664  static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
665                     methodHandle method_h);
666  static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
667                     size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
668                     jmethodID* to_dealloc_id_p,
669                     jmethodID** to_dealloc_jmeths_p);
670  static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
671                size_t *length_p, jmethodID* id_p);
672  jmethodID jmethod_id_or_null(Method* method);
673
674  // cached itable index support
675  void set_cached_itable_index(size_t idnum, int index);
676  int cached_itable_index(size_t idnum);
677
678  // annotations support
679  Annotations* annotations() const          { return _annotations; }
680  void set_annotations(Annotations* anno)   { _annotations = anno; }
681  AnnotationArray* class_annotations() const {
682    if (annotations() == NULL) return NULL;
683    return annotations()->class_annotations();
684  }
685  Array<AnnotationArray*>* fields_annotations() const {
686    if (annotations() == NULL) return NULL;
687    return annotations()->fields_annotations();
688  }
689  Annotations* type_annotations() const {
690    if (annotations() == NULL) return NULL;
691    return annotations()->type_annotations();
692  }
693
694  // allocation
695  instanceOop allocate_instance(TRAPS);
696
697  // additional member function to return a handle
698  instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
699
700  objArrayOop allocate_objArray(int n, int length, TRAPS);
701  // Helper function
702  static instanceOop register_finalizer(instanceOop i, TRAPS);
703
704  // Check whether reflection/jni/jvm code is allowed to instantiate this class;
705  // if not, throw either an Error or an Exception.
706  virtual void check_valid_for_instantiation(bool throwError, TRAPS);
707
708  // initialization
709  void call_class_initializer(TRAPS);
710  void set_initialization_state_and_notify(ClassState state, TRAPS);
711
712  // OopMapCache support
713  OopMapCache* oop_map_cache()               { return _oop_map_cache; }
714  void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
715  void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
716
717  // JNI identifier support (for static fields - for jni performance)
718  JNIid* jni_ids()                               { return _jni_ids; }
719  void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
720  JNIid* jni_id_for(int offset);
721
722  // maintenance of deoptimization dependencies
723  int mark_dependent_nmethods(DepChange& changes);
724  void add_dependent_nmethod(nmethod* nm);
725  void remove_dependent_nmethod(nmethod* nm);
726
727  // On-stack replacement support
728  nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
729  void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
730  void add_osr_nmethod(nmethod* n);
731  void remove_osr_nmethod(nmethod* n);
732  nmethod* lookup_osr_nmethod(Method* const m, int bci, int level, bool match_level) const;
733
734  // Breakpoint support (see methods on Method* for details)
735  BreakpointInfo* breakpoints() const       { return _breakpoints; };
736  void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
737
738  // support for stub routines
739  static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
740  TRACE_DEFINE_OFFSET;
741  static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
742
743  // subclass/subinterface checks
744  bool implements_interface(Klass* k) const;
745
746  // Access to the implementor of an interface.
747  Klass* implementor() const
748  {
749    Klass** k = adr_implementor();
750    if (k == NULL) {
751      return NULL;
752    } else {
753      return *k;
754    }
755  }
756
757  void set_implementor(Klass* k) {
758    assert(is_interface(), "not interface");
759    Klass** addr = adr_implementor();
760    *addr = k;
761  }
762
763  int  nof_implementors() const       {
764    Klass* k = implementor();
765    if (k == NULL) {
766      return 0;
767    } else if (k != this) {
768      return 1;
769    } else {
770      return 2;
771    }
772  }
773
774  void add_implementor(Klass* k);  // k is a new class that implements this interface
775  void init_implementor();           // initialize
776
777  // link this class into the implementors list of every interface it implements
778  void process_interfaces(Thread *thread);
779
780  // virtual operations from Klass
781  bool is_leaf_class() const               { return _subklass == NULL; }
782  GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
783  bool compute_is_subtype_of(Klass* k);
784  bool can_be_primary_super_slow() const;
785  int oop_size(oop obj)  const             { return size_helper(); }
786  bool oop_is_instance_slow() const        { return true; }
787
788  // Iterators
789  void do_local_static_fields(FieldClosure* cl);
790  void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
791  void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);
792
793  void methods_do(void f(Method* method));
794  void array_klasses_do(void f(Klass* k));
795  void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
796  void with_array_klasses_do(void f(Klass* k));
797  bool super_types_do(SuperTypeClosure* blk);
798
799  // Casting from Klass*
800  static InstanceKlass* cast(Klass* k) {
801    assert(k->is_klass(), "must be");
802    assert(k->oop_is_instance(), "cast to InstanceKlass");
803    return (InstanceKlass*) k;
804  }
805
806  InstanceKlass* java_super() const {
807    return (super() == NULL) ? NULL : cast(super());
808  }
809
810  // Sizing (in words)
811  static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
812  static int size(int vtable_length, int itable_length,
813                  int nonstatic_oop_map_size,
814                  bool is_interface, bool is_anonymous) {
815    return align_object_size(header_size() +
816           align_object_offset(vtable_length) +
817           align_object_offset(itable_length) +
818           ((is_interface || is_anonymous) ?
819             align_object_offset(nonstatic_oop_map_size) :
820             nonstatic_oop_map_size) +
821           (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
822           (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
823  }
824  int size() const                    { return size(vtable_length(),
825                                               itable_length(),
826                                               nonstatic_oop_map_size(),
827                                               is_interface(),
828                                               is_anonymous());
829  }
830
831  static int vtable_start_offset()    { return header_size(); }
832  static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
833
834  intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
835  intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
836  int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
837
838  intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
839
840  address static_field_addr(int offset);
841
842  OopMapBlock* start_of_nonstatic_oop_maps() const {
843    return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
844  }
845
846  Klass** adr_implementor() const {
847    if (is_interface()) {
848      return (Klass**)(start_of_nonstatic_oop_maps() +
849                    nonstatic_oop_map_count());
850    } else {
851      return NULL;
852    }
853  };
854
855  Klass** adr_host_klass() const {
856    if (is_anonymous()) {
857      Klass** adr_impl = adr_implementor();
858      if (adr_impl != NULL) {
859        return adr_impl + 1;
860      } else {
861        return (Klass**)(start_of_nonstatic_oop_maps() +
862                      nonstatic_oop_map_count());
863      }
864    } else {
865      return NULL;
866    }
867  }
868
869  // Allocation profiling support
870  juint alloc_size() const            { return _alloc_count * size_helper(); }
871  void set_alloc_size(juint n)        {}
872
873  // Use this to return the size of an instance in heap words:
874  int size_helper() const {
875    return layout_helper_to_size_helper(layout_helper());
876  }
877
878  // This bit is initialized in classFileParser.cpp.
879  // It is false under any of the following conditions:
880  //  - the class is abstract (including any interface)
881  //  - the class has a finalizer (if !RegisterFinalizersAtInit)
882  //  - the class size is larger than FastAllocateSizeLimit
883  //  - the class is java/lang/Class, which cannot be allocated directly
884  bool can_be_fastpath_allocated() const {
885    return !layout_helper_needs_slow_path(layout_helper());
886  }
887
888  // Java vtable/itable
889  klassVtable* vtable() const;        // return new klassVtable wrapper
890  inline Method* method_at_vtable(int index);
891  klassItable* itable() const;        // return new klassItable wrapper
892  Method* method_at_itable(Klass* holder, int index, TRAPS);
893
894  // Garbage collection
895  virtual void oops_do(OopClosure* cl);
896
897  void oop_follow_contents(oop obj);
898  int  oop_adjust_pointers(oop obj);
899
900  void clean_implementors_list(BoolObjectClosure* is_alive);
901  void clean_method_data(BoolObjectClosure* is_alive);
902
903  // Explicit metaspace deallocation of fields
904  // For RedefineClasses, we need to deallocate instanceKlasses
905  void deallocate_contents(ClassLoaderData* loader_data);
906
907  // The constant pool is on stack if any of the methods are executing or
908  // referenced by handles.
909  bool on_stack() const { return _constants->on_stack(); }
910
911  void release_C_heap_structures();
912
913  // Parallel Scavenge and Parallel Old
914  PARALLEL_GC_DECLS
915
916  // Naming
917  const char* signature_name() const;
918
919  // Iterators
920  int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
921    return oop_oop_iterate_v(obj, blk);
922  }
923
924  int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
925    return oop_oop_iterate_v_m(obj, blk, mr);
926  }
927
928#define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
929  int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
930  int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
931                                      MemRegion mr);
932
933  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
934  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
935
936#ifndef SERIALGC
937#define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
938  int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
939
940  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
941  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
942#endif // !SERIALGC
943
944  u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
945private:
946  // initialization state
947#ifdef ASSERT
948  void set_init_state(ClassState state);
949#else
950  void set_init_state(ClassState state) { _init_state = (u1)state; }
951#endif
952  void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
953  void set_init_thread(Thread *thread)  { _init_thread = thread; }
954
955  // The RedefineClasses() API can cause new method idnums to be needed
956  // which will cause the caches to grow. Safety requires different
957  // cache management logic if the caches can grow instead of just
958  // going from NULL to non-NULL.
959  bool idnum_can_increment() const      { return has_been_redefined(); }
960  jmethodID* methods_jmethod_ids_acquire() const
961         { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
962  void release_set_methods_jmethod_ids(jmethodID* jmeths)
963         { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
964
965  int* methods_cached_itable_indices_acquire() const
966         { return (int*)OrderAccess::load_ptr_acquire(&_methods_cached_itable_indices); }
967  void release_set_methods_cached_itable_indices(int* indices)
968         { OrderAccess::release_store_ptr(&_methods_cached_itable_indices, indices); }
969
970  // Lock during initialization
971  volatile oop init_lock() const;
972  void set_init_lock(oop value)      { klass_oop_store(&_init_lock, value); }
973  void fence_and_clear_init_lock();  // after fully_initialized
974
975  // Offsets for memory management
976  oop* adr_protection_domain() const { return (oop*)&this->_protection_domain;}
977  oop* adr_signers() const           { return (oop*)&this->_signers;}
978  oop* adr_init_lock() const         { return (oop*)&this->_init_lock;}
979
980  // Static methods that are used to implement member methods where an exposed this pointer
981  // is needed due to possible GCs
982  static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
983  static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
984  static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
985  static void eager_initialize_impl                     (instanceKlassHandle this_oop);
986  static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
987  static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
988  static Klass* array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
989  static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
990  /* jni_id_for_impl for jfieldID only */
991  static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);
992
993  // Returns the array class for the n'th dimension
994  Klass* array_klass_impl(bool or_null, int n, TRAPS);
995
996  // Returns the array class with this class as element type
997  Klass* array_klass_impl(bool or_null, TRAPS);
998
999public:
1000  // CDS support - remove and restore oops from metadata. Oops are not shared.
1001  virtual void remove_unshareable_info();
1002  virtual void restore_unshareable_info(TRAPS);
1003
1004  // jvm support
1005  jint compute_modifier_flags(TRAPS) const;
1006
1007public:
1008  // JVMTI support
1009  jint jvmti_class_status() const;
1010
1011 public:
1012  // Printing
1013#ifndef PRODUCT
1014  void print_on(outputStream* st) const;
1015#endif
1016  void print_value_on(outputStream* st) const;
1017
1018  void oop_print_value_on(oop obj, outputStream* st);
1019
1020#ifndef PRODUCT
1021  void oop_print_on      (oop obj, outputStream* st);
1022
1023  void print_dependent_nmethods(bool verbose = false);
1024  bool is_dependent_nmethod(nmethod* nm);
1025#endif
1026
1027  const char* internal_name() const;
1028
1029  // Verification
1030  void verify_on(outputStream* st);
1031
1032  void oop_verify_on(oop obj, outputStream* st);
1033};
1034
1035inline Method* InstanceKlass::method_at_vtable(int index)  {
1036#ifndef PRODUCT
1037  assert(index >= 0, "valid vtable index");
1038  if (DebugVtables) {
1039    verify_vtable_index(index);
1040  }
1041#endif
1042  vtableEntry* ve = (vtableEntry*)start_of_vtable();
1043  return ve[index].method();
1044}
1045
1046// for adding methods
1047// UNSET_IDNUM return means no more ids available
1048inline u2 InstanceKlass::next_method_idnum() {
1049  if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1050    return ConstMethod::UNSET_IDNUM; // no more ids available
1051  } else {
1052    return _idnum_allocated_count++;
1053  }
1054}
1055
1056
1057/* JNIid class for jfieldIDs only */
1058class JNIid: public CHeapObj<mtClass> {
1059  friend class VMStructs;
1060 private:
1061  Klass*             _holder;
1062  JNIid*             _next;
1063  int                _offset;
1064#ifdef ASSERT
1065  bool               _is_static_field_id;
1066#endif
1067
1068 public:
1069  // Accessors
1070  Klass* holder() const           { return _holder; }
1071  int offset() const              { return _offset; }
1072  JNIid* next()                   { return _next; }
1073  // Constructor
1074  JNIid(Klass* holder, int offset, JNIid* next);
1075  // Identifier lookup
1076  JNIid* find(int offset);
1077
1078  bool find_local_field(fieldDescriptor* fd) {
1079    return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1080  }
1081
1082  static void deallocate(JNIid* id);
1083  // Debugging
1084#ifdef ASSERT
1085  bool is_static_field_id() const { return _is_static_field_id; }
1086  void set_is_static_field_id()   { _is_static_field_id = true; }
1087#endif
1088  void verify(Klass* holder);
1089};
1090
1091
1092// If breakpoints are more numerous than just JVMTI breakpoints,
1093// consider compressing this data structure.
1094// It is currently a simple linked list defined in method.hpp.
1095
1096class BreakpointInfo;
1097
1098
1099// A collection point for interesting information about the previous
1100// version(s) of an InstanceKlass. This class uses weak references to
1101// the information so that the information may be collected as needed
1102// by the system. If the information is shared, then a regular
1103// reference must be used because a weak reference would be seen as
1104// collectible. A GrowableArray of PreviousVersionNodes is attached
1105// to the InstanceKlass as needed. See PreviousVersionWalker below.
1106class PreviousVersionNode : public CHeapObj<mtClass> {
1107 private:
1108  // A shared ConstantPool is never collected so we'll always have
1109  // a reference to it so we can update items in the cache. We'll
1110  // have a weak reference to a non-shared ConstantPool until all
1111  // of the methods (EMCP or obsolete) have been collected; the
1112  // non-shared ConstantPool becomes collectible at that point.
1113  ConstantPool*    _prev_constant_pool;  // regular or weak reference
1114  bool    _prev_cp_is_weak;     // true if not a shared ConstantPool
1115
1116  // If the previous version of the InstanceKlass doesn't have any
1117  // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
1118  // EMCP methods have been collected, then _prev_EMCP_methods can
1119  // have a length of zero.
1120  GrowableArray<Method*>* _prev_EMCP_methods;
1121
1122public:
1123  PreviousVersionNode(ConstantPool* prev_constant_pool, bool prev_cp_is_weak,
1124    GrowableArray<Method*>* prev_EMCP_methods);
1125  ~PreviousVersionNode();
1126  ConstantPool* prev_constant_pool() const {
1127    return _prev_constant_pool;
1128  }
1129  GrowableArray<Method*>* prev_EMCP_methods() const {
1130    return _prev_EMCP_methods;
1131  }
1132};
1133
1134
1135// A Handle-ized version of PreviousVersionNode.
1136class PreviousVersionInfo : public ResourceObj {
1137 private:
1138  constantPoolHandle   _prev_constant_pool_handle;
1139  // If the previous version of the InstanceKlass doesn't have any
1140  // EMCP methods, then _prev_EMCP_methods will be NULL. Since the
1141  // methods cannot be collected while we hold a handle,
1142  // _prev_EMCP_methods should never have a length of zero.
1143  GrowableArray<methodHandle>* _prev_EMCP_method_handles;
1144
1145public:
1146  PreviousVersionInfo(PreviousVersionNode *pv_node);
1147  ~PreviousVersionInfo();
1148  constantPoolHandle prev_constant_pool_handle() const {
1149    return _prev_constant_pool_handle;
1150  }
1151  GrowableArray<methodHandle>* prev_EMCP_method_handles() const {
1152    return _prev_EMCP_method_handles;
1153  }
1154};
1155
1156
1157// Helper object for walking previous versions. This helper cleans up
1158// the Handles that it allocates when the helper object is destroyed.
1159// The PreviousVersionInfo object returned by next_previous_version()
1160// is only valid until a subsequent call to next_previous_version() or
1161// the helper object is destroyed.
1162class PreviousVersionWalker : public StackObj {
1163 private:
1164  GrowableArray<PreviousVersionNode *>* _previous_versions;
1165  int                                   _current_index;
1166  // Fields for cleaning up when we are done walking the previous versions:
1167  // A HandleMark for the PreviousVersionInfo handles:
1168  HandleMark                            _hm;
1169
1170  // It would be nice to have a ResourceMark field in this helper also,
1171  // but the ResourceMark code says to be careful to delete handles held
1172  // in GrowableArrays _before_ deleting the GrowableArray. Since we
1173  // can't guarantee the order in which the fields are destroyed, we
1174  // have to let the creator of the PreviousVersionWalker object do
1175  // the right thing. Also, adding a ResourceMark here causes an
1176  // include loop.
1177
1178  // A pointer to the current info object so we can handle the deletes.
1179  PreviousVersionInfo *                 _current_p;
1180
1181 public:
1182  PreviousVersionWalker(InstanceKlass *ik);
1183  ~PreviousVersionWalker();
1184
1185  // Return the interesting information for the next previous version
1186  // of the klass. Returns NULL if there are no more previous versions.
1187  PreviousVersionInfo* next_previous_version();
1188};
1189
1190
1191//
1192// nmethodBucket is used to record dependent nmethods for
1193// deoptimization.  nmethod dependencies are actually <klass, method>
1194// pairs but we really only care about the klass part for purposes of
1195// finding nmethods which might need to be deoptimized.  Instead of
1196// recording the method, a count of how many times a particular nmethod
1197// was recorded is kept.  This ensures that any recording errors are
1198// noticed since an nmethod should be removed as many times are it's
1199// added.
1200//
1201class nmethodBucket: public CHeapObj<mtClass> {
1202  friend class VMStructs;
1203 private:
1204  nmethod*       _nmethod;
1205  int            _count;
1206  nmethodBucket* _next;
1207
1208 public:
1209  nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1210    _nmethod = nmethod;
1211    _next = next;
1212    _count = 1;
1213  }
1214  int count()                             { return _count; }
1215  int increment()                         { _count += 1; return _count; }
1216  int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1217  nmethodBucket* next()                   { return _next; }
1218  void set_next(nmethodBucket* b)         { _next = b; }
1219  nmethod* get_nmethod()                  { return _nmethod; }
1220};
1221
1222// An iterator that's used to access the inner classes indices in the
1223// InstanceKlass::_inner_classes array.
1224class InnerClassesIterator : public StackObj {
1225 private:
1226  Array<jushort>* _inner_classes;
1227  int _length;
1228  int _idx;
1229 public:
1230
1231  InnerClassesIterator(instanceKlassHandle k) {
1232    _inner_classes = k->inner_classes();
1233    if (k->inner_classes() != NULL) {
1234      _length = _inner_classes->length();
1235      // The inner class array's length should be the multiple of
1236      // inner_class_next_offset if it only contains the InnerClasses
1237      // attribute data, or it should be
1238      // n*inner_class_next_offset+enclosing_method_attribute_size
1239      // if it also contains the EnclosingMethod data.
1240      assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1241              _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1242             "just checking");
1243      // Remove the enclosing_method portion if exists.
1244      if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1245        _length -= InstanceKlass::enclosing_method_attribute_size;
1246      }
1247    } else {
1248      _length = 0;
1249    }
1250    _idx = 0;
1251  }
1252
1253  int length() const {
1254    return _length;
1255  }
1256
1257  void next() {
1258    _idx += InstanceKlass::inner_class_next_offset;
1259  }
1260
1261  bool done() const {
1262    return (_idx >= _length);
1263  }
1264
1265  u2 inner_class_info_index() const {
1266    return _inner_classes->at(
1267               _idx + InstanceKlass::inner_class_inner_class_info_offset);
1268  }
1269
1270  void set_inner_class_info_index(u2 index) {
1271    _inner_classes->at_put(
1272               _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1273  }
1274
1275  u2 outer_class_info_index() const {
1276    return _inner_classes->at(
1277               _idx + InstanceKlass::inner_class_outer_class_info_offset);
1278  }
1279
1280  void set_outer_class_info_index(u2 index) {
1281    _inner_classes->at_put(
1282               _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1283  }
1284
1285  u2 inner_name_index() const {
1286    return _inner_classes->at(
1287               _idx + InstanceKlass::inner_class_inner_name_offset);
1288  }
1289
1290  void set_inner_name_index(u2 index) {
1291    _inner_classes->at_put(
1292               _idx + InstanceKlass::inner_class_inner_name_offset, index);
1293  }
1294
1295  u2 inner_access_flags() const {
1296    return _inner_classes->at(
1297               _idx + InstanceKlass::inner_class_access_flags_offset);
1298  }
1299};
1300
1301#endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP
1302