instanceKlass.hpp revision 4277:3efdfd6ddbf2
1/*
2 * Copyright (c) 1997, 2013, 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
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7 * published by the Free Software Foundation.
8 *
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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,
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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#include "utilities/macros.hpp"
40
41// An InstanceKlass is the VM level representation of a Java class.
42// It contains all information needed for at class at execution runtime.
43
44//  InstanceKlass layout:
45//    [C++ vtbl pointer           ] Klass
46//    [subtype cache              ] Klass
47//    [instance size              ] Klass
48//    [java mirror                ] Klass
49//    [super                      ] Klass
50//    [access_flags               ] Klass
51//    [name                       ] Klass
52//    [first subklass             ] Klass
53//    [next sibling               ] Klass
54//    [array klasses              ]
55//    [methods                    ]
56//    [local interfaces           ]
57//    [transitive interfaces      ]
58//    [fields                     ]
59//    [constants                  ]
60//    [class loader               ]
61//    [protection domain          ]
62//    [signers                    ]
63//    [source file name           ]
64//    [inner classes              ]
65//    [static field size          ]
66//    [nonstatic field size       ]
67//    [static oop fields size     ]
68//    [nonstatic oop maps size    ]
69//    [has finalize method        ]
70//    [deoptimization mark bit    ]
71//    [initialization state       ]
72//    [initializing thread        ]
73//    [Java vtable length         ]
74//    [oop map cache (stack maps) ]
75//    [EMBEDDED Java vtable             ] size in words = vtable_len
76//    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
77//      The embedded nonstatic oop-map blocks are short pairs (offset, length)
78//      indicating where oops are located in instances of this klass.
79//    [EMBEDDED implementor of the interface] only exist for interface
80//    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
81
82
83// forward declaration for class -- see below for definition
84class SuperTypeClosure;
85class JNIid;
86class jniIdMapBase;
87class BreakpointInfo;
88class fieldDescriptor;
89class DepChange;
90class nmethodBucket;
91class PreviousVersionNode;
92class JvmtiCachedClassFieldMap;
93
94// This is used in iterators below.
95class FieldClosure: public StackObj {
96public:
97  virtual void do_field(fieldDescriptor* fd) = 0;
98};
99
100#ifndef PRODUCT
101// Print fields.
102// If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
103class FieldPrinter: public FieldClosure {
104   oop _obj;
105   outputStream* _st;
106 public:
107   FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
108   void do_field(fieldDescriptor* fd);
109};
110#endif  // !PRODUCT
111
112// ValueObjs embedded in klass. Describes where oops are located in instances of
113// this klass.
114class OopMapBlock VALUE_OBJ_CLASS_SPEC {
115 public:
116  // Byte offset of the first oop mapped by this block.
117  int offset() const          { return _offset; }
118  void set_offset(int offset) { _offset = offset; }
119
120  // Number of oops in this block.
121  uint count() const         { return _count; }
122  void set_count(uint count) { _count = count; }
123
124  // sizeof(OopMapBlock) in HeapWords.
125  static const int size_in_words() {
126    return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
127      LogHeapWordSize;
128  }
129
130 private:
131  int  _offset;
132  uint _count;
133};
134
135class InstanceKlass: public Klass {
136  friend class VMStructs;
137  friend class ClassFileParser;
138  friend class CompileReplay;
139
140 protected:
141  // Constructor
142  InstanceKlass(int vtable_len,
143                int itable_len,
144                int static_field_size,
145                int nonstatic_oop_map_size,
146                ReferenceType rt,
147                AccessFlags access_flags,
148                bool is_anonymous);
149 public:
150  static Klass* allocate_instance_klass(ClassLoaderData* loader_data,
151                                          int vtable_len,
152                                          int itable_len,
153                                          int static_field_size,
154                                          int nonstatic_oop_map_size,
155                                          ReferenceType rt,
156                                          AccessFlags access_flags,
157                                          Symbol* name,
158                                          Klass* super_klass,
159                                          bool is_anonymous,
160                                          TRAPS);
161
162  InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
163
164  // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
165  // of the class loading & initialization procedure, and the use of the states.
166  enum ClassState {
167    allocated,                          // allocated (but not yet linked)
168    loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
169    linked,                             // successfully linked/verified (but not initialized yet)
170    being_initialized,                  // currently running class initializer
171    fully_initialized,                  // initialized (successfull final state)
172    initialization_error                // error happened during initialization
173  };
174
175  static int number_of_instance_classes() { return _total_instanceKlass_count; }
176
177 private:
178  static volatile int _total_instanceKlass_count;
179
180 protected:
181  // Protection domain.
182  oop             _protection_domain;
183  // Class signers.
184  objArrayOop     _signers;
185  // Initialization lock.  Must be one per class and it has to be a VM internal
186  // object so java code cannot lock it (like the mirror)
187  // It has to be an object not a Mutex because it's held through java calls.
188  volatile oop    _init_lock;
189
190  // Annotations for this class
191  Annotations*    _annotations;
192  // Array classes holding elements of this class.
193  Klass*          _array_klasses;
194  // Constant pool for this class.
195  ConstantPool* _constants;
196  // The InnerClasses attribute and EnclosingMethod attribute. The
197  // _inner_classes is an array of shorts. If the class has InnerClasses
198  // attribute, then the _inner_classes array begins with 4-tuples of shorts
199  // [inner_class_info_index, outer_class_info_index,
200  // inner_name_index, inner_class_access_flags] for the InnerClasses
201  // attribute. If the EnclosingMethod attribute exists, it occupies the
202  // last two shorts [class_index, method_index] of the array. If only
203  // the InnerClasses attribute exists, the _inner_classes array length is
204  // number_of_inner_classes * 4. If the class has both InnerClasses
205  // and EnclosingMethod attributes the _inner_classes array length is
206  // number_of_inner_classes * 4 + enclosing_method_attribute_size.
207  Array<jushort>* _inner_classes;
208
209  // Name of source file containing this klass, NULL if not specified.
210  Symbol*         _source_file_name;
211  // the source debug extension for this klass, NULL if not specified.
212  // Specified as UTF-8 string without terminating zero byte in the classfile,
213  // it is stored in the instanceklass as a NULL-terminated UTF-8 string
214  char*           _source_debug_extension;
215  // Generic signature, or null if none.
216  Symbol*         _generic_signature;
217  // Array name derived from this class which needs unreferencing
218  // if this class is unloaded.
219  Symbol*         _array_name;
220
221  // Number of heapOopSize words used by non-static fields in this klass
222  // (including inherited fields but after header_size()).
223  int             _nonstatic_field_size;
224  int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
225  u2              _static_oop_field_count;// number of static oop fields in this klass
226  u2              _java_fields_count;    // The number of declared Java fields
227  int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
228
229  // _is_marked_dependent can be set concurrently, thus cannot be part of the
230  // _misc_flags.
231  bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
232
233  enum {
234    _misc_rewritten            = 1 << 0, // methods rewritten.
235    _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
236    _misc_should_verify_class  = 1 << 2, // allow caching of preverification
237    _misc_is_anonymous         = 1 << 3, // has embedded _inner_classes field
238    _misc_is_contended         = 1 << 4, // marked with contended annotation
239    _misc_has_default_methods  = 1 << 5  // class/superclass/implemented interfaces has default methods
240  };
241  u2              _misc_flags;
242  u2              _minor_version;        // minor version number of class file
243  u2              _major_version;        // major version number of class file
244  Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
245  int             _vtable_len;           // length of Java vtable (in words)
246  int             _itable_len;           // length of Java itable (in words)
247  OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
248  JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
249  jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
250  int*            _methods_cached_itable_indices;  // itable_index cache for JNI invoke corresponding to methods idnum, or NULL
251  nmethodBucket*  _dependencies;         // list of dependent nmethods
252  nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
253  BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
254  // Array of interesting part(s) of the previous version(s) of this
255  // InstanceKlass. See PreviousVersionWalker below.
256  GrowableArray<PreviousVersionNode *>* _previous_versions;
257  // JVMTI fields can be moved to their own structure - see 6315920
258  unsigned char * _cached_class_file_bytes;       // JVMTI: cached class file, before retransformable agent modified it in CFLH
259  jint            _cached_class_file_len;         // JVMTI: length of above
260
261  volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
262
263  // Class states are defined as ClassState (see above).
264  // Place the _init_state here to utilize the unused 2-byte after
265  // _idnum_allocated_count.
266  u1              _init_state;                    // state of class
267  u1              _reference_type;                // reference type
268
269
270  JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
271
272  NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
273
274  // Method array.
275  Array<Method*>* _methods;
276  // Interface (Klass*s) this class declares locally to implement.
277  Array<Klass*>* _local_interfaces;
278  // Interface (Klass*s) this class implements transitively.
279  Array<Klass*>* _transitive_interfaces;
280  // Int array containing the original order of method in the class file (for JVMTI).
281  Array<int>*     _method_ordering;
282  // Instance and static variable information, starts with 6-tuples of shorts
283  // [access, name index, sig index, initval index, low_offset, high_offset]
284  // for all fields, followed by the generic signature data at the end of
285  // the array. Only fields with generic signature attributes have the generic
286  // signature data set in the array. The fields array looks like following:
287  //
288  // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
289  // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
290  //      ...
291  // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
292  //     [generic signature index]
293  //     [generic signature index]
294  //     ...
295  Array<u2>*      _fields;
296
297  // embedded Java vtable follows here
298  // embedded Java itables follows here
299  // embedded static fields follows here
300  // embedded nonstatic oop-map blocks follows here
301  // embedded implementor of this interface follows here
302  //   The embedded implementor only exists if the current klass is an
303  //   iterface. The possible values of the implementor fall into following
304  //   three cases:
305  //     NULL: no implementor.
306  //     A Klass* that's not itself: one implementor.
307  //     Itsef: more than one implementors.
308  // embedded host klass follows here
309  //   The embedded host klass only exists in an anonymous class for
310  //   dynamic language support (JSR 292 enabled). The host class grants
311  //   its access privileges to this class also. The host class is either
312  //   named, or a previously loaded anonymous class. A non-anonymous class
313  //   or an anonymous class loaded through normal classloading does not
314  //   have this embedded field.
315  //
316
317  friend class SystemDictionary;
318
319 public:
320  bool has_nonstatic_fields() const        {
321    return (_misc_flags & _misc_has_nonstatic_fields) != 0;
322  }
323  void set_has_nonstatic_fields(bool b)    {
324    if (b) {
325      _misc_flags |= _misc_has_nonstatic_fields;
326    } else {
327      _misc_flags &= ~_misc_has_nonstatic_fields;
328    }
329  }
330
331  // field sizes
332  int nonstatic_field_size() const         { return _nonstatic_field_size; }
333  void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
334
335  int static_field_size() const            { return _static_field_size; }
336  void set_static_field_size(int size)     { _static_field_size = size; }
337
338  int static_oop_field_count() const       { return (int)_static_oop_field_count; }
339  void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
340
341  // Java vtable
342  int  vtable_length() const               { return _vtable_len; }
343  void set_vtable_length(int len)          { _vtable_len = len; }
344
345  // Java itable
346  int  itable_length() const               { return _itable_len; }
347  void set_itable_length(int len)          { _itable_len = len; }
348
349  // array klasses
350  Klass* array_klasses() const             { return _array_klasses; }
351  void set_array_klasses(Klass* k)         { _array_klasses = k; }
352
353  // methods
354  Array<Method*>* methods() const          { return _methods; }
355  void set_methods(Array<Method*>* a)      { _methods = a; }
356  Method* method_with_idnum(int idnum);
357
358  // method ordering
359  Array<int>* method_ordering() const     { return _method_ordering; }
360  void set_method_ordering(Array<int>* m) { _method_ordering = m; }
361
362  // interfaces
363  Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
364  void set_local_interfaces(Array<Klass*>* a)      {
365    guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
366    _local_interfaces = a; }
367  Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
368  void set_transitive_interfaces(Array<Klass*>* a) {
369    guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
370    _transitive_interfaces = a; }
371
372 private:
373  friend class fieldDescriptor;
374  FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
375
376 public:
377  int     field_offset      (int index) const { return field(index)->offset(); }
378  int     field_access_flags(int index) const { return field(index)->access_flags(); }
379  Symbol* field_name        (int index) const { return field(index)->name(constants()); }
380  Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
381
382  // Number of Java declared fields
383  int java_fields_count() const           { return (int)_java_fields_count; }
384
385  Array<u2>* fields() const            { return _fields; }
386
387  void set_fields(Array<u2>* f, u2 java_fields_count) {
388    guarantee(_fields == NULL || f == NULL, "Just checking");
389    _fields =  f;
390    _java_fields_count = java_fields_count;
391  }
392
393  // inner classes
394  Array<u2>* inner_classes() const       { return _inner_classes; }
395  void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
396
397  enum InnerClassAttributeOffset {
398    // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
399    inner_class_inner_class_info_offset = 0,
400    inner_class_outer_class_info_offset = 1,
401    inner_class_inner_name_offset = 2,
402    inner_class_access_flags_offset = 3,
403    inner_class_next_offset = 4
404  };
405
406  enum EnclosingMethodAttributeOffset {
407    enclosing_method_class_index_offset = 0,
408    enclosing_method_method_index_offset = 1,
409    enclosing_method_attribute_size = 2
410  };
411
412  // method override check
413  bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
414
415  // package
416  bool is_same_class_package(Klass* class2);
417  bool is_same_class_package(oop classloader2, Symbol* classname2);
418  static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
419
420  // find an enclosing class (defined where original code was, in jvm.cpp!)
421  Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
422    instanceKlassHandle self(THREAD, this);
423    return compute_enclosing_class_impl(self, inner_is_member, THREAD);
424  }
425  static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
426                                               bool* inner_is_member, TRAPS);
427
428  // tell if two classes have the same enclosing class (at package level)
429  bool is_same_package_member(Klass* class2, TRAPS) {
430    instanceKlassHandle self(THREAD, this);
431    return is_same_package_member_impl(self, class2, THREAD);
432  }
433  static bool is_same_package_member_impl(instanceKlassHandle self,
434                                          Klass* class2, TRAPS);
435
436  // initialization state
437  bool is_loaded() const                   { return _init_state >= loaded; }
438  bool is_linked() const                   { return _init_state >= linked; }
439  bool is_initialized() const              { return _init_state == fully_initialized; }
440  bool is_not_initialized() const          { return _init_state <  being_initialized; }
441  bool is_being_initialized() const        { return _init_state == being_initialized; }
442  bool is_in_error_state() const           { return _init_state == initialization_error; }
443  bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
444  ClassState  init_state()                 { return (ClassState)_init_state; }
445  bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
446
447  // defineClass specified verification
448  bool should_verify_class() const         {
449    return (_misc_flags & _misc_should_verify_class) != 0;
450  }
451  void set_should_verify_class(bool value) {
452    if (value) {
453      _misc_flags |= _misc_should_verify_class;
454    } else {
455      _misc_flags &= ~_misc_should_verify_class;
456    }
457  }
458
459  // marking
460  bool is_marked_dependent() const         { return _is_marked_dependent; }
461  void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
462
463  // initialization (virtuals from Klass)
464  bool should_be_initialized() const;  // means that initialize should be called
465  void initialize(TRAPS);
466  void link_class(TRAPS);
467  bool link_class_or_fail(TRAPS); // returns false on failure
468  void unlink_class();
469  void rewrite_class(TRAPS);
470  void link_methods(TRAPS);
471  Method* class_initializer();
472
473  // set the class to initialized if no static initializer is present
474  void eager_initialize(Thread *thread);
475
476  // reference type
477  ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
478  void set_reference_type(ReferenceType t) {
479    assert(t == (u1)t, "overflow");
480    _reference_type = (u1)t;
481  }
482
483  static ByteSize reference_type_offset() { return in_ByteSize(offset_of(InstanceKlass, _reference_type)); }
484
485  // find local field, returns true if found
486  bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
487  // find field in direct superinterfaces, returns the interface in which the field is defined
488  Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
489  // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
490  Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
491  // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
492  Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
493
494  // find a non-static or static field given its offset within the class.
495  bool contains_field_offset(int offset) {
496    return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());
497  }
498
499  bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
500  bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
501
502  // find a local method (returns NULL if not found)
503  Method* find_method(Symbol* name, Symbol* signature) const;
504  static Method* find_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
505
506  // lookup operation (returns NULL if not found)
507  Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
508
509  // lookup a method in all the interfaces that this class implements
510  // (returns NULL if not found)
511  Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;
512
513  // Find method indices by name.  If a method with the specified name is
514  // found the index to the first method is returned, and 'end' is filled in
515  // with the index of first non-name-matching method.  If no method is found
516  // -1 is returned.
517  int find_method_by_name(Symbol* name, int* end);
518  static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
519
520  // constant pool
521  ConstantPool* constants() const        { return _constants; }
522  void set_constants(ConstantPool* c)    { _constants = c; }
523
524  // protection domain
525  oop protection_domain()                  { return _protection_domain; }
526  void set_protection_domain(oop pd)       { klass_oop_store(&_protection_domain, pd); }
527
528  // host class
529  Klass* host_klass() const              {
530    Klass** hk = (Klass**)adr_host_klass();
531    if (hk == NULL) {
532      return NULL;
533    } else {
534      return *hk;
535    }
536  }
537  void set_host_klass(Klass* host)            {
538    assert(is_anonymous(), "not anonymous");
539    Klass** addr = (Klass**)adr_host_klass();
540    assert(addr != NULL, "no reversed space");
541    *addr = host;
542  }
543  bool is_anonymous() const                {
544    return (_misc_flags & _misc_is_anonymous) != 0;
545  }
546  void set_is_anonymous(bool value)        {
547    if (value) {
548      _misc_flags |= _misc_is_anonymous;
549    } else {
550      _misc_flags &= ~_misc_is_anonymous;
551    }
552  }
553
554  // Oop that keeps the metadata for this class from being unloaded
555  // in places where the metadata is stored in other places, like nmethods
556  oop klass_holder() const {
557    return is_anonymous() ? java_mirror() : class_loader();
558  }
559
560  bool is_contended() const                {
561    return (_misc_flags & _misc_is_contended) != 0;
562  }
563  void set_is_contended(bool value)        {
564    if (value) {
565      _misc_flags |= _misc_is_contended;
566    } else {
567      _misc_flags &= ~_misc_is_contended;
568    }
569  }
570
571  // signers
572  objArrayOop signers() const              { return _signers; }
573  void set_signers(objArrayOop s)          { klass_oop_store((oop*)&_signers, s); }
574
575  // source file name
576  Symbol* source_file_name() const         { return _source_file_name; }
577  void set_source_file_name(Symbol* n);
578
579  // minor and major version numbers of class file
580  u2 minor_version() const                 { return _minor_version; }
581  void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
582  u2 major_version() const                 { return _major_version; }
583  void set_major_version(u2 major_version) { _major_version = major_version; }
584
585  // source debug extension
586  char* source_debug_extension() const     { return _source_debug_extension; }
587  void set_source_debug_extension(char* array, int length);
588
589  // symbol unloading support (refcount already added)
590  Symbol* array_name()                     { return _array_name; }
591  void set_array_name(Symbol* name)        { assert(_array_name == NULL  || name == NULL, "name already created"); _array_name = name; }
592
593  // nonstatic oop-map blocks
594  static int nonstatic_oop_map_size(unsigned int oop_map_count) {
595    return oop_map_count * OopMapBlock::size_in_words();
596  }
597  unsigned int nonstatic_oop_map_count() const {
598    return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
599  }
600  int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
601  void set_nonstatic_oop_map_size(int words) {
602    _nonstatic_oop_map_size = words;
603  }
604
605  // RedefineClasses() support for previous versions:
606  void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
607         int emcp_method_count);
608  // If the _previous_versions array is non-NULL, then this klass
609  // has been redefined at least once even if we aren't currently
610  // tracking a previous version.
611  bool has_been_redefined() const { return _previous_versions != NULL; }
612  bool has_previous_version() const;
613  void init_previous_versions() {
614    _previous_versions = NULL;
615  }
616  GrowableArray<PreviousVersionNode *>* previous_versions() const {
617    return _previous_versions;
618  }
619
620  static void purge_previous_versions(InstanceKlass* ik);
621
622  // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
623  void set_cached_class_file(unsigned char *class_file_bytes,
624                             jint class_file_len)     { _cached_class_file_len = class_file_len;
625                                                        _cached_class_file_bytes = class_file_bytes; }
626  jint get_cached_class_file_len()                    { return _cached_class_file_len; }
627  unsigned char * get_cached_class_file_bytes()       { return _cached_class_file_bytes; }
628
629  // JVMTI: Support for caching of field indices, types, and offsets
630  void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
631    _jvmti_cached_class_field_map = descriptor;
632  }
633  JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
634    return _jvmti_cached_class_field_map;
635  }
636
637  bool has_default_methods() const {
638    return (_misc_flags & _misc_has_default_methods) != 0;
639  }
640  void set_has_default_methods(bool b) {
641    if (b) {
642      _misc_flags |= _misc_has_default_methods;
643    } else {
644      _misc_flags &= ~_misc_has_default_methods;
645    }
646  }
647
648  // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
649  inline u2 next_method_idnum();
650  void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
651
652  // generics support
653  Symbol* generic_signature() const                   { return _generic_signature; }
654  void set_generic_signature(Symbol* sig)             { _generic_signature = sig; }
655
656  u2 enclosing_method_data(int offset);
657  u2 enclosing_method_class_index() {
658    return enclosing_method_data(enclosing_method_class_index_offset);
659  }
660  u2 enclosing_method_method_index() {
661    return enclosing_method_data(enclosing_method_method_index_offset);
662  }
663  void set_enclosing_method_indices(u2 class_index,
664                                    u2 method_index);
665
666  // jmethodID support
667  static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
668                     methodHandle method_h);
669  static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
670                     size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
671                     jmethodID* to_dealloc_id_p,
672                     jmethodID** to_dealloc_jmeths_p);
673  static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
674                size_t *length_p, jmethodID* id_p);
675  jmethodID jmethod_id_or_null(Method* method);
676
677  // cached itable index support
678  void set_cached_itable_index(size_t idnum, int index);
679  int cached_itable_index(size_t idnum);
680
681  // annotations support
682  Annotations* annotations() const          { return _annotations; }
683  void set_annotations(Annotations* anno)   { _annotations = anno; }
684
685  AnnotationArray* class_annotations() const {
686    return (_annotations != NULL) ? _annotations->class_annotations() : NULL;
687  }
688  Array<AnnotationArray*>* fields_annotations() const {
689    return (_annotations != NULL) ? _annotations->fields_annotations() : NULL;
690  }
691  AnnotationArray* class_type_annotations() const {
692    return (_annotations != NULL) ? _annotations->class_type_annotations() : NULL;
693  }
694  Array<AnnotationArray*>* fields_type_annotations() const {
695    return (_annotations != NULL) ? _annotations->fields_type_annotations() : NULL;
696  }
697  // allocation
698  instanceOop allocate_instance(TRAPS);
699
700  // additional member function to return a handle
701  instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
702
703  objArrayOop allocate_objArray(int n, int length, TRAPS);
704  // Helper function
705  static instanceOop register_finalizer(instanceOop i, TRAPS);
706
707  // Check whether reflection/jni/jvm code is allowed to instantiate this class;
708  // if not, throw either an Error or an Exception.
709  virtual void check_valid_for_instantiation(bool throwError, TRAPS);
710
711  // initialization
712  void call_class_initializer(TRAPS);
713  void set_initialization_state_and_notify(ClassState state, TRAPS);
714
715  // OopMapCache support
716  OopMapCache* oop_map_cache()               { return _oop_map_cache; }
717  void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
718  void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
719
720  // JNI identifier support (for static fields - for jni performance)
721  JNIid* jni_ids()                               { return _jni_ids; }
722  void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
723  JNIid* jni_id_for(int offset);
724
725  // maintenance of deoptimization dependencies
726  int mark_dependent_nmethods(DepChange& changes);
727  void add_dependent_nmethod(nmethod* nm);
728  void remove_dependent_nmethod(nmethod* nm);
729
730  // On-stack replacement support
731  nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
732  void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
733  void add_osr_nmethod(nmethod* n);
734  void remove_osr_nmethod(nmethod* n);
735  nmethod* lookup_osr_nmethod(Method* const m, int bci, int level, bool match_level) const;
736
737  // Breakpoint support (see methods on Method* for details)
738  BreakpointInfo* breakpoints() const       { return _breakpoints; };
739  void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
740
741  // support for stub routines
742  static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
743  TRACE_DEFINE_OFFSET;
744  static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
745
746  // subclass/subinterface checks
747  bool implements_interface(Klass* k) const;
748
749  // Access to the implementor of an interface.
750  Klass* implementor() const
751  {
752    Klass** k = adr_implementor();
753    if (k == NULL) {
754      return NULL;
755    } else {
756      return *k;
757    }
758  }
759
760  void set_implementor(Klass* k) {
761    assert(is_interface(), "not interface");
762    Klass** addr = adr_implementor();
763    *addr = k;
764  }
765
766  int  nof_implementors() const       {
767    Klass* k = implementor();
768    if (k == NULL) {
769      return 0;
770    } else if (k != this) {
771      return 1;
772    } else {
773      return 2;
774    }
775  }
776
777  void add_implementor(Klass* k);  // k is a new class that implements this interface
778  void init_implementor();           // initialize
779
780  // link this class into the implementors list of every interface it implements
781  void process_interfaces(Thread *thread);
782
783  // virtual operations from Klass
784  bool is_leaf_class() const               { return _subklass == NULL; }
785  GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
786  bool compute_is_subtype_of(Klass* k);
787  bool can_be_primary_super_slow() const;
788  int oop_size(oop obj)  const             { return size_helper(); }
789  bool oop_is_instance_slow() const        { return true; }
790
791  // Iterators
792  void do_local_static_fields(FieldClosure* cl);
793  void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
794  void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);
795
796  void methods_do(void f(Method* method));
797  void array_klasses_do(void f(Klass* k));
798  void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
799  void with_array_klasses_do(void f(Klass* k));
800  bool super_types_do(SuperTypeClosure* blk);
801
802  // Casting from Klass*
803  static InstanceKlass* cast(Klass* k) {
804    assert(k->is_klass(), "must be");
805    assert(k->oop_is_instance(), "cast to InstanceKlass");
806    return (InstanceKlass*) k;
807  }
808
809  InstanceKlass* java_super() const {
810    return (super() == NULL) ? NULL : cast(super());
811  }
812
813  // Sizing (in words)
814  static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
815
816  static int size(int vtable_length, int itable_length,
817                  int nonstatic_oop_map_size,
818                  bool is_interface, bool is_anonymous) {
819    return align_object_size(header_size() +
820           align_object_offset(vtable_length) +
821           align_object_offset(itable_length) +
822           ((is_interface || is_anonymous) ?
823             align_object_offset(nonstatic_oop_map_size) :
824             nonstatic_oop_map_size) +
825           (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
826           (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
827  }
828  int size() const                    { return size(vtable_length(),
829                                               itable_length(),
830                                               nonstatic_oop_map_size(),
831                                               is_interface(),
832                                               is_anonymous());
833  }
834#if INCLUDE_SERVICES
835  virtual void collect_statistics(KlassSizeStats *sz) const;
836#endif
837
838  static int vtable_start_offset()    { return header_size(); }
839  static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
840
841  intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
842  intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
843  int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
844
845  intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
846
847  address static_field_addr(int offset);
848
849  OopMapBlock* start_of_nonstatic_oop_maps() const {
850    return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
851  }
852
853  Klass** end_of_nonstatic_oop_maps() const {
854    return (Klass**)(start_of_nonstatic_oop_maps() +
855                     nonstatic_oop_map_count());
856  }
857
858  Klass** adr_implementor() const {
859    if (is_interface()) {
860      return (Klass**)end_of_nonstatic_oop_maps();
861    } else {
862      return NULL;
863    }
864  };
865
866  Klass** adr_host_klass() const {
867    if (is_anonymous()) {
868      Klass** adr_impl = adr_implementor();
869      if (adr_impl != NULL) {
870        return adr_impl + 1;
871      } else {
872        return end_of_nonstatic_oop_maps();
873      }
874    } else {
875      return NULL;
876    }
877  }
878
879  // Allocation profiling support
880  juint alloc_size() const            { return _alloc_count * size_helper(); }
881  void set_alloc_size(juint n)        {}
882
883  // Use this to return the size of an instance in heap words:
884  int size_helper() const {
885    return layout_helper_to_size_helper(layout_helper());
886  }
887
888  // This bit is initialized in classFileParser.cpp.
889  // It is false under any of the following conditions:
890  //  - the class is abstract (including any interface)
891  //  - the class has a finalizer (if !RegisterFinalizersAtInit)
892  //  - the class size is larger than FastAllocateSizeLimit
893  //  - the class is java/lang/Class, which cannot be allocated directly
894  bool can_be_fastpath_allocated() const {
895    return !layout_helper_needs_slow_path(layout_helper());
896  }
897
898  // Java vtable/itable
899  klassVtable* vtable() const;        // return new klassVtable wrapper
900  inline Method* method_at_vtable(int index);
901  klassItable* itable() const;        // return new klassItable wrapper
902  Method* method_at_itable(Klass* holder, int index, TRAPS);
903
904  // Garbage collection
905  virtual void oops_do(OopClosure* cl);
906
907  void oop_follow_contents(oop obj);
908  int  oop_adjust_pointers(oop obj);
909
910  void clean_implementors_list(BoolObjectClosure* is_alive);
911  void clean_method_data(BoolObjectClosure* is_alive);
912
913  // Explicit metaspace deallocation of fields
914  // For RedefineClasses, we need to deallocate instanceKlasses
915  void deallocate_contents(ClassLoaderData* loader_data);
916
917  // The constant pool is on stack if any of the methods are executing or
918  // referenced by handles.
919  bool on_stack() const { return _constants->on_stack(); }
920
921  void release_C_heap_structures();
922
923  // Parallel Scavenge and Parallel Old
924  PARALLEL_GC_DECLS
925
926  // Naming
927  const char* signature_name() const;
928
929  // Iterators
930  int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
931    return oop_oop_iterate_v(obj, blk);
932  }
933
934  int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
935    return oop_oop_iterate_v_m(obj, blk, mr);
936  }
937
938#define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
939  int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
940  int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
941                                      MemRegion mr);
942
943  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
944  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
945
946#if INCLUDE_ALL_GCS
947#define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
948  int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
949
950  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
951  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
952#endif // INCLUDE_ALL_GCS
953
954  u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
955private:
956  // initialization state
957#ifdef ASSERT
958  void set_init_state(ClassState state);
959#else
960  void set_init_state(ClassState state) { _init_state = (u1)state; }
961#endif
962  void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
963  void set_init_thread(Thread *thread)  { _init_thread = thread; }
964
965  // The RedefineClasses() API can cause new method idnums to be needed
966  // which will cause the caches to grow. Safety requires different
967  // cache management logic if the caches can grow instead of just
968  // going from NULL to non-NULL.
969  bool idnum_can_increment() const      { return has_been_redefined(); }
970  jmethodID* methods_jmethod_ids_acquire() const
971         { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
972  void release_set_methods_jmethod_ids(jmethodID* jmeths)
973         { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
974
975  int* methods_cached_itable_indices_acquire() const
976         { return (int*)OrderAccess::load_ptr_acquire(&_methods_cached_itable_indices); }
977  void release_set_methods_cached_itable_indices(int* indices)
978         { OrderAccess::release_store_ptr(&_methods_cached_itable_indices, indices); }
979
980  // Lock during initialization
981  volatile oop init_lock() const;
982  void set_init_lock(oop value)      { klass_oop_store(&_init_lock, value); }
983  void fence_and_clear_init_lock();  // after fully_initialized
984
985  // Offsets for memory management
986  oop* adr_protection_domain() const { return (oop*)&this->_protection_domain;}
987  oop* adr_signers() const           { return (oop*)&this->_signers;}
988  oop* adr_init_lock() const         { return (oop*)&this->_init_lock;}
989
990  // Static methods that are used to implement member methods where an exposed this pointer
991  // is needed due to possible GCs
992  static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
993  static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
994  static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
995  static void eager_initialize_impl                     (instanceKlassHandle this_oop);
996  static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
997  static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
998  static Klass* array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
999  static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
1000  /* jni_id_for_impl for jfieldID only */
1001  static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);
1002
1003  // Returns the array class for the n'th dimension
1004  Klass* array_klass_impl(bool or_null, int n, TRAPS);
1005
1006  // Returns the array class with this class as element type
1007  Klass* array_klass_impl(bool or_null, TRAPS);
1008
1009public:
1010  // CDS support - remove and restore oops from metadata. Oops are not shared.
1011  virtual void remove_unshareable_info();
1012  virtual void restore_unshareable_info(TRAPS);
1013
1014  // jvm support
1015  jint compute_modifier_flags(TRAPS) const;
1016
1017public:
1018  // JVMTI support
1019  jint jvmti_class_status() const;
1020
1021 public:
1022  // Printing
1023#ifndef PRODUCT
1024  void print_on(outputStream* st) const;
1025#endif
1026  void print_value_on(outputStream* st) const;
1027
1028  void oop_print_value_on(oop obj, outputStream* st);
1029
1030#ifndef PRODUCT
1031  void oop_print_on      (oop obj, outputStream* st);
1032
1033  void print_dependent_nmethods(bool verbose = false);
1034  bool is_dependent_nmethod(nmethod* nm);
1035#endif
1036
1037  const char* internal_name() const;
1038
1039  // Verification
1040  void verify_on(outputStream* st);
1041
1042  void oop_verify_on(oop obj, outputStream* st);
1043};
1044
1045inline Method* InstanceKlass::method_at_vtable(int index)  {
1046#ifndef PRODUCT
1047  assert(index >= 0, "valid vtable index");
1048  if (DebugVtables) {
1049    verify_vtable_index(index);
1050  }
1051#endif
1052  vtableEntry* ve = (vtableEntry*)start_of_vtable();
1053  return ve[index].method();
1054}
1055
1056// for adding methods
1057// UNSET_IDNUM return means no more ids available
1058inline u2 InstanceKlass::next_method_idnum() {
1059  if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1060    return ConstMethod::UNSET_IDNUM; // no more ids available
1061  } else {
1062    return _idnum_allocated_count++;
1063  }
1064}
1065
1066
1067/* JNIid class for jfieldIDs only */
1068class JNIid: public CHeapObj<mtClass> {
1069  friend class VMStructs;
1070 private:
1071  Klass*             _holder;
1072  JNIid*             _next;
1073  int                _offset;
1074#ifdef ASSERT
1075  bool               _is_static_field_id;
1076#endif
1077
1078 public:
1079  // Accessors
1080  Klass* holder() const           { return _holder; }
1081  int offset() const              { return _offset; }
1082  JNIid* next()                   { return _next; }
1083  // Constructor
1084  JNIid(Klass* holder, int offset, JNIid* next);
1085  // Identifier lookup
1086  JNIid* find(int offset);
1087
1088  bool find_local_field(fieldDescriptor* fd) {
1089    return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1090  }
1091
1092  static void deallocate(JNIid* id);
1093  // Debugging
1094#ifdef ASSERT
1095  bool is_static_field_id() const { return _is_static_field_id; }
1096  void set_is_static_field_id()   { _is_static_field_id = true; }
1097#endif
1098  void verify(Klass* holder);
1099};
1100
1101
1102// If breakpoints are more numerous than just JVMTI breakpoints,
1103// consider compressing this data structure.
1104// It is currently a simple linked list defined in method.hpp.
1105
1106class BreakpointInfo;
1107
1108
1109// A collection point for interesting information about the previous
1110// version(s) of an InstanceKlass. This class uses weak references to
1111// the information so that the information may be collected as needed
1112// by the system. If the information is shared, then a regular
1113// reference must be used because a weak reference would be seen as
1114// collectible. A GrowableArray of PreviousVersionNodes is attached
1115// to the InstanceKlass as needed. See PreviousVersionWalker below.
1116class PreviousVersionNode : public CHeapObj<mtClass> {
1117 private:
1118  // A shared ConstantPool is never collected so we'll always have
1119  // a reference to it so we can update items in the cache. We'll
1120  // have a weak reference to a non-shared ConstantPool until all
1121  // of the methods (EMCP or obsolete) have been collected; the
1122  // non-shared ConstantPool becomes collectible at that point.
1123  ConstantPool*    _prev_constant_pool;  // regular or weak reference
1124  bool    _prev_cp_is_weak;     // true if not a shared ConstantPool
1125
1126  // If the previous version of the InstanceKlass doesn't have any
1127  // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
1128  // EMCP methods have been collected, then _prev_EMCP_methods can
1129  // have a length of zero.
1130  GrowableArray<Method*>* _prev_EMCP_methods;
1131
1132public:
1133  PreviousVersionNode(ConstantPool* prev_constant_pool, bool prev_cp_is_weak,
1134    GrowableArray<Method*>* prev_EMCP_methods);
1135  ~PreviousVersionNode();
1136  ConstantPool* prev_constant_pool() const {
1137    return _prev_constant_pool;
1138  }
1139  GrowableArray<Method*>* prev_EMCP_methods() const {
1140    return _prev_EMCP_methods;
1141  }
1142};
1143
1144
1145// A Handle-ized version of PreviousVersionNode.
1146class PreviousVersionInfo : public ResourceObj {
1147 private:
1148  constantPoolHandle   _prev_constant_pool_handle;
1149  // If the previous version of the InstanceKlass doesn't have any
1150  // EMCP methods, then _prev_EMCP_methods will be NULL. Since the
1151  // methods cannot be collected while we hold a handle,
1152  // _prev_EMCP_methods should never have a length of zero.
1153  GrowableArray<methodHandle>* _prev_EMCP_method_handles;
1154
1155public:
1156  PreviousVersionInfo(PreviousVersionNode *pv_node);
1157  ~PreviousVersionInfo();
1158  constantPoolHandle prev_constant_pool_handle() const {
1159    return _prev_constant_pool_handle;
1160  }
1161  GrowableArray<methodHandle>* prev_EMCP_method_handles() const {
1162    return _prev_EMCP_method_handles;
1163  }
1164};
1165
1166
1167// Helper object for walking previous versions. This helper cleans up
1168// the Handles that it allocates when the helper object is destroyed.
1169// The PreviousVersionInfo object returned by next_previous_version()
1170// is only valid until a subsequent call to next_previous_version() or
1171// the helper object is destroyed.
1172class PreviousVersionWalker : public StackObj {
1173 private:
1174  GrowableArray<PreviousVersionNode *>* _previous_versions;
1175  int                                   _current_index;
1176  // Fields for cleaning up when we are done walking the previous versions:
1177  // A HandleMark for the PreviousVersionInfo handles:
1178  HandleMark                            _hm;
1179
1180  // It would be nice to have a ResourceMark field in this helper also,
1181  // but the ResourceMark code says to be careful to delete handles held
1182  // in GrowableArrays _before_ deleting the GrowableArray. Since we
1183  // can't guarantee the order in which the fields are destroyed, we
1184  // have to let the creator of the PreviousVersionWalker object do
1185  // the right thing. Also, adding a ResourceMark here causes an
1186  // include loop.
1187
1188  // A pointer to the current info object so we can handle the deletes.
1189  PreviousVersionInfo *                 _current_p;
1190
1191 public:
1192  PreviousVersionWalker(InstanceKlass *ik);
1193  ~PreviousVersionWalker();
1194
1195  // Return the interesting information for the next previous version
1196  // of the klass. Returns NULL if there are no more previous versions.
1197  PreviousVersionInfo* next_previous_version();
1198};
1199
1200
1201//
1202// nmethodBucket is used to record dependent nmethods for
1203// deoptimization.  nmethod dependencies are actually <klass, method>
1204// pairs but we really only care about the klass part for purposes of
1205// finding nmethods which might need to be deoptimized.  Instead of
1206// recording the method, a count of how many times a particular nmethod
1207// was recorded is kept.  This ensures that any recording errors are
1208// noticed since an nmethod should be removed as many times are it's
1209// added.
1210//
1211class nmethodBucket: public CHeapObj<mtClass> {
1212  friend class VMStructs;
1213 private:
1214  nmethod*       _nmethod;
1215  int            _count;
1216  nmethodBucket* _next;
1217
1218 public:
1219  nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1220    _nmethod = nmethod;
1221    _next = next;
1222    _count = 1;
1223  }
1224  int count()                             { return _count; }
1225  int increment()                         { _count += 1; return _count; }
1226  int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1227  nmethodBucket* next()                   { return _next; }
1228  void set_next(nmethodBucket* b)         { _next = b; }
1229  nmethod* get_nmethod()                  { return _nmethod; }
1230};
1231
1232// An iterator that's used to access the inner classes indices in the
1233// InstanceKlass::_inner_classes array.
1234class InnerClassesIterator : public StackObj {
1235 private:
1236  Array<jushort>* _inner_classes;
1237  int _length;
1238  int _idx;
1239 public:
1240
1241  InnerClassesIterator(instanceKlassHandle k) {
1242    _inner_classes = k->inner_classes();
1243    if (k->inner_classes() != NULL) {
1244      _length = _inner_classes->length();
1245      // The inner class array's length should be the multiple of
1246      // inner_class_next_offset if it only contains the InnerClasses
1247      // attribute data, or it should be
1248      // n*inner_class_next_offset+enclosing_method_attribute_size
1249      // if it also contains the EnclosingMethod data.
1250      assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1251              _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1252             "just checking");
1253      // Remove the enclosing_method portion if exists.
1254      if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1255        _length -= InstanceKlass::enclosing_method_attribute_size;
1256      }
1257    } else {
1258      _length = 0;
1259    }
1260    _idx = 0;
1261  }
1262
1263  int length() const {
1264    return _length;
1265  }
1266
1267  void next() {
1268    _idx += InstanceKlass::inner_class_next_offset;
1269  }
1270
1271  bool done() const {
1272    return (_idx >= _length);
1273  }
1274
1275  u2 inner_class_info_index() const {
1276    return _inner_classes->at(
1277               _idx + InstanceKlass::inner_class_inner_class_info_offset);
1278  }
1279
1280  void set_inner_class_info_index(u2 index) {
1281    _inner_classes->at_put(
1282               _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1283  }
1284
1285  u2 outer_class_info_index() const {
1286    return _inner_classes->at(
1287               _idx + InstanceKlass::inner_class_outer_class_info_offset);
1288  }
1289
1290  void set_outer_class_info_index(u2 index) {
1291    _inner_classes->at_put(
1292               _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1293  }
1294
1295  u2 inner_name_index() const {
1296    return _inner_classes->at(
1297               _idx + InstanceKlass::inner_class_inner_name_offset);
1298  }
1299
1300  void set_inner_name_index(u2 index) {
1301    _inner_classes->at_put(
1302               _idx + InstanceKlass::inner_class_inner_name_offset, index);
1303  }
1304
1305  u2 inner_access_flags() const {
1306    return _inner_classes->at(
1307               _idx + InstanceKlass::inner_class_access_flags_offset);
1308  }
1309};
1310
1311#endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP
1312