1 /*
2 * Copyright (c) 1997, 2014, 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.
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23 */
24
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
27
28 #include "memory/genOopClosures.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "memory/specialized_oop_closures.hpp"
32 #include "oops/klassPS.hpp"
33 #include "oops/metadata.hpp"
34 #include "oops/oop.hpp"
35 #include "trace/traceMacros.hpp"
36 #include "utilities/accessFlags.hpp"
37 #include "utilities/macros.hpp"
38 #if INCLUDE_ALL_GCS
39 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp"
40 #include "gc_implementation/g1/g1OopClosures.hpp"
41 #include "gc_implementation/parNew/parOopClosures.hpp"
42 #endif // INCLUDE_ALL_GCS
43
44 //
45 // A Klass provides:
46 // 1: language level class object (method dictionary etc.)
47 // 2: provide vm dispatch behavior for the object
48 // Both functions are combined into one C++ class.
49
50 // One reason for the oop/klass dichotomy in the implementation is
51 // that we don't want a C++ vtbl pointer in every object. Thus,
52 // normal oops don't have any virtual functions. Instead, they
53 // forward all "virtual" functions to their klass, which does have
54 // a vtbl and does the C++ dispatch depending on the object's
55 // actual type. (See oop.inline.hpp for some of the forwarding code.)
56 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
57
58 // Forward declarations.
59 template <class T> class Array;
60 template <class T> class GrowableArray;
61 class ClassLoaderData;
62 class klassVtable;
63 class ParCompactionManager;
64 class KlassSizeStats;
65
66 class Klass : public Metadata {
67 friend class VMStructs;
68 public:
69 enum DispatchTag {
70 _instance,
71 _instance_ref,
72 _instance_mirror,
73 _instance_class_loader,
74 _type_array,
75 _obj_array
76 };
77
78 protected:
79 enum { _primary_super_limit = 8 };
80
81 // note: put frequently-used fields together at start of klass structure
82 // for better cache behavior (may not make much of a difference but sure won't hurt)
83
84 // The "layout helper" is a combined descriptor of object layout.
85 // For klasses which are neither instance nor array, the value is zero.
86 //
87 // For instances, layout helper is a positive number, the instance size.
88 // This size is already passed through align_object_size and scaled to bytes.
89 // The low order bit is set if instances of this class cannot be
90 // allocated using the fastpath.
91 //
92 // For arrays, layout helper is a negative number, containing four
93 // distinct bytes, as follows:
94 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
95 // where:
96 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
97 // hsz is array header size in bytes (i.e., offset of first element)
98 // ebt is the BasicType of the elements
99 // esz is the element size in bytes
100 // This packed word is arranged so as to be quickly unpacked by the
101 // various fast paths that use the various subfields.
102 //
103 // The esz bits can be used directly by a SLL instruction, without masking.
104 //
105 // Note that the array-kind tag looks like 0x00 for instance klasses,
106 // since their length in bytes is always less than 24Mb.
107 //
108 // Final note: This comes first, immediately after C++ vtable,
109 // because it is frequently queried.
110 jint _layout_helper;
111
112 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
113 // and _primary_supers all help make fast subtype checks. See big discussion
114 // in doc/server_compiler/checktype.txt
115 //
116 // Where to look to observe a supertype (it is &_secondary_super_cache for
117 // secondary supers, else is &_primary_supers[depth()].
118 juint _super_check_offset;
119
120 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
121 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
122 Symbol* _name;
123
124 // Cache of last observed secondary supertype
125 Klass* _secondary_super_cache;
126 // Array of all secondary supertypes
127 Array<Klass*>* _secondary_supers;
128 // Ordered list of all primary supertypes
129 Klass* _primary_supers[_primary_super_limit];
130 // java/lang/Class instance mirroring this class
131 oop _java_mirror;
132 // Superclass
133 Klass* _super;
134 // First subclass (NULL if none); _subklass->next_sibling() is next one
135 Klass* _subklass;
136 // Sibling link (or NULL); links all subklasses of a klass
137 Klass* _next_sibling;
138
139 // All klasses loaded by a class loader are chained through these links
140 Klass* _next_link;
141
142 // The VM's representation of the ClassLoader used to load this class.
143 // Provide access the corresponding instance java.lang.ClassLoader.
144 ClassLoaderData* _class_loader_data;
145
146 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
147 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
148
149 // Biased locking implementation and statistics
150 // (the 64-bit chunk goes first, to avoid some fragmentation)
151 jlong _last_biased_lock_bulk_revocation_time;
152 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
153 jint _biased_lock_revocation_count;
154
155 TRACE_DEFINE_KLASS_TRACE_ID;
156
157 // Remembered sets support for the oops in the klasses.
158 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support)
159 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
160
161 const DispatchTag _dispatch_tag;
162
163 // Constructor
164 Klass(DispatchTag dispatch_tag, bool dummy /*ignored*/) : _dispatch_tag(_instance) {} // SSS: For Dummy objects
165 Klass(DispatchTag dispatch_tag);
166
167 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
168
169 public:
170 enum MethodLookupMode { normal, skip_overpass, skip_defaults };
171
172 bool is_klass() const volatile { return true; }
173
174 DispatchTag dispatch_tag() const { return _dispatch_tag; }
175
176 // super
177 Klass* super() const { return _super; }
178 void set_super(Klass* k) { _super = k; }
179
180 // initializes _super link, _primary_supers & _secondary_supers arrays
181 void initialize_supers(Klass* k, TRAPS);
182 void initialize_supers_impl1(Klass* k);
183 void initialize_supers_impl2(Klass* k);
184
185 // klass-specific helper for initializing _secondary_supers
186 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
187
188 // java_super is the Java-level super type as specified by Class.getSuperClass.
189 virtual Klass* java_super() const { return NULL; }
190
191 juint super_check_offset() const { return _super_check_offset; }
192 void set_super_check_offset(juint o) { _super_check_offset = o; }
193
194 Klass* secondary_super_cache() const { return _secondary_super_cache; }
195 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
196
197 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
198 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
199
200 // Return the element of the _super chain of the given depth.
201 // If there is no such element, return either NULL or this.
202 Klass* primary_super_of_depth(juint i) const {
203 assert(i < primary_super_limit(), "oob");
204 Klass* super = _primary_supers[i];
205 assert(super == NULL || super->super_depth() == i, "correct display");
206 return super;
207 }
208
209 // Can this klass be a primary super? False for interfaces and arrays of
210 // interfaces. False also for arrays or classes with long super chains.
211 bool can_be_primary_super() const {
212 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
213 return super_check_offset() != secondary_offset;
214 }
215 virtual bool can_be_primary_super_slow() const;
216
217 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
218 juint super_depth() const {
219 if (!can_be_primary_super()) {
220 return primary_super_limit();
221 } else {
222 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
223 assert(d < primary_super_limit(), "oob");
224 assert(_primary_supers[d] == this, "proper init");
225 return d;
226 }
227 }
228
229 // store an oop into a field of a Klass
230 void klass_oop_store(oop* p, oop v);
231 void klass_oop_store(volatile oop* p, oop v);
232
233 // java mirror
234 oop java_mirror() const { return _java_mirror; }
235 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); }
236
237 // modifier flags
238 jint modifier_flags() const { return _modifier_flags; }
239 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
240
241 // size helper
242 int layout_helper() const { return _layout_helper; }
243 void set_layout_helper(int lh) { _layout_helper = lh; }
244
245 // Note: for instances layout_helper() may include padding.
246 // Use InstanceKlass::contains_field_offset to classify field offsets.
247
248 // sub/superklass links
249 Klass* subklass() const { return _subklass; }
250 Klass* next_sibling() const { return _next_sibling; }
251 InstanceKlass* superklass() const;
252 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
253
254 void set_next_link(Klass* k) { _next_link = k; }
255 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
256
257 // class loader data
258 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
259 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
260
261 // The Klasses are not placed in the Heap, so the Card Table or
262 // the Mod Union Table can't be used to mark when klasses have modified oops.
263 // The CT and MUT bits saves this information for the individual Klasses.
264 void record_modified_oops() { _modified_oops = 1; }
265 void clear_modified_oops() { _modified_oops = 0; }
266 bool has_modified_oops() { return _modified_oops == 1; }
267
268 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; }
269 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; }
270 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; }
271
272 protected: // internal accessors
273 void set_subklass(Klass* s);
274 void set_next_sibling(Klass* s);
275
276 public:
277
278 // Compiler support
279 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
280 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
281 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
282 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
283 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
284 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
285 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
286 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
287 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
288
289 // Unpacking layout_helper:
290 enum {
291 _lh_neutral_value = 0, // neutral non-array non-instance value
292 _lh_instance_slow_path_bit = 0x01,
293 _lh_log2_element_size_shift = BitsPerByte*0,
294 _lh_log2_element_size_mask = BitsPerLong-1,
295 _lh_element_type_shift = BitsPerByte*1,
296 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
297 _lh_header_size_shift = BitsPerByte*2,
298 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
299 _lh_array_tag_bits = 2,
300 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
301 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
302 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
303 };
304
305 static int layout_helper_size_in_bytes(jint lh) {
306 assert(lh > (jint)_lh_neutral_value, "must be instance");
307 return (int) lh & ~_lh_instance_slow_path_bit;
308 }
309 static bool layout_helper_needs_slow_path(jint lh) {
310 assert(lh > (jint)_lh_neutral_value, "must be instance");
311 return (lh & _lh_instance_slow_path_bit) != 0;
312 }
313 static bool layout_helper_is_instance(jint lh) {
314 return (jint)lh > (jint)_lh_neutral_value;
315 }
316 static bool layout_helper_is_array(jint lh) {
317 return (jint)lh < (jint)_lh_neutral_value;
318 }
319 static bool layout_helper_is_typeArray(jint lh) {
320 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
321 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
322 }
323 static bool layout_helper_is_objArray(jint lh) {
324 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
325 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
326 }
327 static int layout_helper_header_size(jint lh) {
328 assert(lh < (jint)_lh_neutral_value, "must be array");
329 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
330 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
331 return hsize;
332 }
333 static BasicType layout_helper_element_type(jint lh) {
334 assert(lh < (jint)_lh_neutral_value, "must be array");
335 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
336 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
337 return (BasicType) btvalue;
338 }
339 static int layout_helper_log2_element_size(jint lh) {
340 assert(lh < (jint)_lh_neutral_value, "must be array");
341 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
342 assert(l2esz <= LogBitsPerLong,
343 err_msg("sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh));
344 return l2esz;
345 }
346 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
347 return (tag << _lh_array_tag_shift)
348 | (hsize << _lh_header_size_shift)
349 | ((int)etype << _lh_element_type_shift)
350 | (log2_esize << _lh_log2_element_size_shift);
351 }
352 static jint instance_layout_helper(jint size, bool slow_path_flag) {
353 return (size << LogHeapWordSize)
354 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
355 }
356 static int layout_helper_to_size_helper(jint lh) {
357 assert(lh > (jint)_lh_neutral_value, "must be instance");
358 // Note that the following expression discards _lh_instance_slow_path_bit.
359 return lh >> LogHeapWordSize;
360 }
361 // Out-of-line version computes everything based on the etype:
362 static jint array_layout_helper(BasicType etype);
363
364 // What is the maximum number of primary superclasses any klass can have?
365 #ifdef PRODUCT
366 static juint primary_super_limit() { return _primary_super_limit; }
367 #else
368 static juint primary_super_limit() {
369 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
370 return FastSuperclassLimit;
371 }
372 #endif
373
374 // vtables
375 virtual klassVtable* vtable() const { return NULL; }
376 virtual int vtable_length() const { return 0; }
377
378 // subclass check
379 bool is_subclass_of(const Klass* k) const;
380 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
381 bool is_subtype_of(Klass* k) const {
382 juint off = k->super_check_offset();
383 Klass* sup = *(Klass**)( (address)this + off );
384 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
385 if (sup == k) {
386 return true;
387 } else if (off != secondary_offset) {
388 return false;
389 } else {
390 return search_secondary_supers(k);
391 }
392 }
393 bool search_secondary_supers(Klass* k) const;
394
395 // Find LCA in class hierarchy
396 Klass *LCA( Klass *k );
397
398 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
399 // if not, throw either an Error or an Exception.
400 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
401
402 // array copying
403 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
404
405 // tells if the class should be initialized
406 virtual bool should_be_initialized() const { return false; }
407 // initializes the klass
408 virtual void initialize(TRAPS);
409 // lookup operation for MethodLookupCache
410 friend class MethodLookupCache;
411 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature, MethodLookupMode mode) const;
412 public:
413 Method* lookup_method(Symbol* name, Symbol* signature) const {
414 return uncached_lookup_method(name, signature, normal);
415 }
416
417 // array class with specific rank
418 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
419
420 // array class with this klass as element type
421 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
422
423 // These will return NULL instead of allocating on the heap:
424 // NB: these can block for a mutex, like other functions with TRAPS arg.
425 Klass* array_klass_or_null(int rank);
426 Klass* array_klass_or_null();
427
428 virtual oop protection_domain() const = 0;
429
430 oop class_loader() const;
431
432 virtual oop klass_holder() const { return class_loader(); }
433
434 protected:
435 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
436 virtual Klass* array_klass_impl(bool or_null, TRAPS);
437
438 public:
439 // CDS support - remove and restore oops from metadata. Oops are not shared.
440 virtual void remove_unshareable_info();
441 virtual void restore_unshareable_info(TRAPS);
442
443 protected:
444 // computes the subtype relationship
445 virtual bool compute_is_subtype_of(Klass* k);
446 public:
447 // subclass accessor (here for convenience; undefined for non-klass objects)
448 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
449 public:
450 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
451 // These functions describe behavior for the oop not the KLASS.
452
453 // actual oop size of obj in memory
454 virtual int oop_size(oop obj) const = 0;
455
456 // Size of klass in word size.
457 virtual int size() const = 0;
458 #if INCLUDE_SERVICES
459 virtual void collect_statistics(KlassSizeStats *sz) const;
460 #endif
461
462 // Returns the Java name for a class (Resource allocated)
463 // For arrays, this returns the name of the element with a leading '['.
464 // For classes, this returns the name with the package separators
465 // turned into '.'s.
466 const char* external_name() const;
467 // Returns the name for a class (Resource allocated) as the class
468 // would appear in a signature.
469 // For arrays, this returns the name of the element with a leading '['.
470 // For classes, this returns the name with a leading 'L' and a trailing ';'
471 // and the package separators as '/'.
472 virtual const char* signature_name() const;
473
474 // garbage collection support
475 virtual void oop_follow_contents(oop obj) = 0;
476 virtual int oop_adjust_pointers(oop obj) = 0;
477
478 // Parallel Scavenge and Parallel Old
479 PARALLEL_GC_DECLS_PV
480
481 // type testing operations
482 protected:
483 virtual bool oop_is_instance_slow() const { return false; }
484 virtual bool oop_is_array_slow() const { return false; }
485 virtual bool oop_is_objArray_slow() const { return false; }
486 virtual bool oop_is_typeArray_slow() const { return false; }
487 public:
488 virtual bool oop_is_instanceClassLoader() const { return false; }
489 virtual bool oop_is_instanceMirror() const { return false; }
490 virtual bool oop_is_instanceRef() const { return false; }
491
492 // Fast non-virtual versions
493 #ifndef ASSERT
494 #define assert_same_query(xval, xcheck) xval
495 #else
496 private:
497 static bool assert_same_query(bool xval, bool xslow) {
498 assert(xval == xslow, "slow and fast queries agree");
499 return xval;
500 }
501 public:
502 #endif
503 inline bool oop_is_instance() const { return assert_same_query(
504 layout_helper_is_instance(layout_helper()),
505 oop_is_instance_slow()); }
506 inline bool oop_is_array() const { return assert_same_query(
507 layout_helper_is_array(layout_helper()),
508 oop_is_array_slow()); }
509 inline bool oop_is_objArray() const { return assert_same_query(
510 layout_helper_is_objArray(layout_helper()),
511 oop_is_objArray_slow()); }
512 inline bool oop_is_typeArray() const { return assert_same_query(
513 layout_helper_is_typeArray(layout_helper()),
514 oop_is_typeArray_slow()); }
515 #undef assert_same_query
516
517 // Access flags
518 AccessFlags access_flags() const { return _access_flags; }
519 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
520
521 bool is_public() const { return _access_flags.is_public(); }
522 bool is_final() const { return _access_flags.is_final(); }
523 bool is_interface() const { return _access_flags.is_interface(); }
524 bool is_abstract() const { return _access_flags.is_abstract(); }
525 bool is_super() const { return _access_flags.is_super(); }
526 bool is_synthetic() const { return _access_flags.is_synthetic(); }
527 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
528 bool has_finalizer() const { return _access_flags.has_finalizer(); }
529 bool has_final_method() const { return _access_flags.has_final_method(); }
530 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
531 void set_has_final_method() { _access_flags.set_has_final_method(); }
532 bool is_cloneable() const { return _access_flags.is_cloneable(); }
533 void set_is_cloneable() { _access_flags.set_is_cloneable(); }
534 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
535 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
536 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
537 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
538
539 // Biased locking support
540 // Note: the prototype header is always set up to be at least the
541 // prototype markOop. If biased locking is enabled it may further be
542 // biasable and have an epoch.
543 markOop prototype_header() const { return _prototype_header; }
544 // NOTE: once instances of this klass are floating around in the
545 // system, this header must only be updated at a safepoint.
546 // NOTE 2: currently we only ever set the prototype header to the
547 // biasable prototype for instanceKlasses. There is no technical
548 // reason why it could not be done for arrayKlasses aside from
549 // wanting to reduce the initial scope of this optimization. There
550 // are potential problems in setting the bias pattern for
551 // JVM-internal oops.
552 inline void set_prototype_header(markOop header);
553 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
554
555 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
556 // Atomically increments biased_lock_revocation_count and returns updated value
557 int atomic_incr_biased_lock_revocation_count();
558 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
559 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
560 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
561
562 TRACE_DEFINE_KLASS_METHODS;
563
564 // garbage collection support
565 virtual void oops_do(OopClosure* cl);
566
567 // Iff the class loader (or mirror for anonymous classes) is alive the
568 // Klass is considered alive.
569 // The is_alive closure passed in depends on the Garbage Collector used.
570 bool is_loader_alive(BoolObjectClosure* is_alive);
571
572 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true);
573 static void clean_subklass_tree(BoolObjectClosure* is_alive) {
574 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */);
575 }
576
577 virtual void array_klasses_do(void f(Klass* k)) {}
578
579 // Return self, except for abstract classes with exactly 1
580 // implementor. Then return the 1 concrete implementation.
581 Klass *up_cast_abstract();
582
583 // klass name
584 Symbol* name() const { return _name; }
585 void set_name(Symbol* n);
586
587 public:
588 // jvm support
589 virtual jint compute_modifier_flags(TRAPS) const;
590
591 // JVMTI support
592 virtual jint jvmti_class_status() const;
593
594 // Printing
595 virtual void print_on(outputStream* st) const;
596
597 virtual void oop_print_value_on(oop obj, outputStream* st);
598 virtual void oop_print_on (oop obj, outputStream* st);
599
600 virtual const char* internal_name() const = 0;
601
602 // Verification
603 virtual void verify_on(outputStream* st);
604 void verify() { verify_on(tty); }
605
606 #ifndef PRODUCT
607 bool verify_vtable_index(int index);
608 bool verify_itable_index(int index);
609 #endif
610
611 virtual void oop_verify_on(oop obj, outputStream* st);
612
613 static bool is_null(narrowKlass obj);
614 static bool is_null(Klass* obj);
615
616 // klass encoding for klass pointer in objects.
617 static narrowKlass encode_klass_not_null(Klass* v);
618 static narrowKlass encode_klass(Klass* v);
619
620 static Klass* decode_klass_not_null(narrowKlass v);
621 static Klass* decode_klass(narrowKlass v);
622
623 private:
624 // barriers used by klass_oop_store
625 void klass_update_barrier_set(oop v);
626 void klass_update_barrier_set_pre(oop* p, oop v);
627 };
628
629 #endif // SHARE_VM_OOPS_KLASS_HPP