1 /*
2 * Copyright (c) 1997, 2018, 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 "utilities/accessFlags.hpp"
36 #include "utilities/macros.hpp"
37 #if INCLUDE_ALL_GCS
38 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp"
39 #include "gc_implementation/g1/g1OopClosures.hpp"
40 #include "gc_implementation/parNew/parOopClosures.hpp"
41 #endif // INCLUDE_ALL_GCS
42 #if INCLUDE_JFR
43 #include "jfr/support/jfrTraceIdExtension.hpp"
44 #endif
45
46 //
47 // A Klass provides:
48 // 1: language level class object (method dictionary etc.)
49 // 2: provide vm dispatch behavior for the object
50 // Both functions are combined into one C++ class.
51
52 // One reason for the oop/klass dichotomy in the implementation is
53 // that we don't want a C++ vtbl pointer in every object. Thus,
54 // normal oops don't have any virtual functions. Instead, they
55 // forward all "virtual" functions to their klass, which does have
56 // a vtbl and does the C++ dispatch depending on the object's
57 // actual type. (See oop.inline.hpp for some of the forwarding code.)
58 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
59
60 // Klass layout:
61 // [C++ vtbl ptr ] (contained in Metadata)
62 // [layout_helper ]
63 // [super_check_offset ] for fast subtype checks
64 // [name ]
65 // [secondary_super_cache] for fast subtype checks
66 // [secondary_supers ] array of 2ndary supertypes
67 // [primary_supers 0]
68 // [primary_supers 1]
69 // [primary_supers 2]
70 // ...
71 // [primary_supers 7]
72 // [java_mirror ]
73 // [super ]
74 // [subklass ] first subclass
75 // [next_sibling ] link to chain additional subklasses
76 // [next_link ]
77 // [class_loader_data]
78 // [modifier_flags]
79 // [access_flags ]
80 // [last_biased_lock_bulk_revocation_time] (64 bits)
81 // [prototype_header]
82 // [biased_lock_revocation_count]
83 // [_modified_oops]
84 // [_accumulated_modified_oops]
85 // [trace_id]
86
87
88 // Forward declarations.
89 template <class T> class Array;
90 template <class T> class GrowableArray;
91 class ClassLoaderData;
92 class klassVtable;
93 class ParCompactionManager;
94 class KlassSizeStats;
95 class fieldDescriptor;
96
97 class Klass : public Metadata {
98 friend class VMStructs;
99 protected:
100 // note: put frequently-used fields together at start of klass structure
101 // for better cache behavior (may not make much of a difference but sure won't hurt)
102 enum { _primary_super_limit = 8 };
103
104 // The "layout helper" is a combined descriptor of object layout.
105 // For klasses which are neither instance nor array, the value is zero.
106 //
107 // For instances, layout helper is a positive number, the instance size.
108 // This size is already passed through align_object_size and scaled to bytes.
109 // The low order bit is set if instances of this class cannot be
110 // allocated using the fastpath.
111 //
112 // For arrays, layout helper is a negative number, containing four
113 // distinct bytes, as follows:
114 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
115 // where:
116 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
117 // hsz is array header size in bytes (i.e., offset of first element)
118 // ebt is the BasicType of the elements
119 // esz is the element size in bytes
120 // This packed word is arranged so as to be quickly unpacked by the
121 // various fast paths that use the various subfields.
122 //
123 // The esz bits can be used directly by a SLL instruction, without masking.
124 //
125 // Note that the array-kind tag looks like 0x00 for instance klasses,
126 // since their length in bytes is always less than 24Mb.
127 //
128 // Final note: This comes first, immediately after C++ vtable,
129 // because it is frequently queried.
130 jint _layout_helper;
131
132 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
133 // and _primary_supers all help make fast subtype checks. See big discussion
134 // in doc/server_compiler/checktype.txt
135 //
136 // Where to look to observe a supertype (it is &_secondary_super_cache for
137 // secondary supers, else is &_primary_supers[depth()].
138 juint _super_check_offset;
139
140 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
141 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
142 Symbol* _name;
143
144 // Cache of last observed secondary supertype
145 Klass* _secondary_super_cache;
146 // Array of all secondary supertypes
147 Array<Klass*>* _secondary_supers;
148 // Ordered list of all primary supertypes
149 Klass* _primary_supers[_primary_super_limit];
150 // java/lang/Class instance mirroring this class
151 oop _java_mirror;
152 // Superclass
153 Klass* _super;
154 // First subclass (NULL if none); _subklass->next_sibling() is next one
155 Klass* _subklass;
156 // Sibling link (or NULL); links all subklasses of a klass
157 Klass* _next_sibling;
158
159 // All klasses loaded by a class loader are chained through these links
160 Klass* _next_link;
161
162 // The VM's representation of the ClassLoader used to load this class.
163 // Provide access the corresponding instance java.lang.ClassLoader.
164 ClassLoaderData* _class_loader_data;
165
166 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
167 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
168
169 // Biased locking implementation and statistics
170 // (the 64-bit chunk goes first, to avoid some fragmentation)
171 jlong _last_biased_lock_bulk_revocation_time;
172 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
173 jint _biased_lock_revocation_count;
174
175 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
176
177 // Remembered sets support for the oops in the klasses.
178 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support)
179 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
180
181 private:
182 // This is an index into FileMapHeader::_classpath_entry_table[], to
183 // associate this class with the JAR file where it's loaded from during
184 // dump time. If a class is not loaded from the shared archive, this field is
185 // -1.
186 jshort _shared_class_path_index;
187
188 friend class SharedClassUtil;
189 protected:
190
191 // Constructor
192 Klass();
193
194 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
195
196 public:
197 enum DefaultsLookupMode { find_defaults, skip_defaults };
198 enum OverpassLookupMode { find_overpass, skip_overpass };
199 enum StaticLookupMode { find_static, skip_static };
200 enum PrivateLookupMode { find_private, skip_private };
201
202 bool is_klass() const volatile { return true; }
203
204 // super
205 Klass* super() const { return _super; }
206 void set_super(Klass* k) { _super = k; }
207
208 // initializes _super link, _primary_supers & _secondary_supers arrays
209 void initialize_supers(Klass* k, TRAPS);
210 void initialize_supers_impl1(Klass* k);
211 void initialize_supers_impl2(Klass* k);
212
213 // klass-specific helper for initializing _secondary_supers
214 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
215
216 // java_super is the Java-level super type as specified by Class.getSuperClass.
217 virtual Klass* java_super() const { return NULL; }
218
219 juint super_check_offset() const { return _super_check_offset; }
220 void set_super_check_offset(juint o) { _super_check_offset = o; }
221
222 Klass* secondary_super_cache() const { return _secondary_super_cache; }
223 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
224
225 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
226 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
227
228 // Return the element of the _super chain of the given depth.
229 // If there is no such element, return either NULL or this.
230 Klass* primary_super_of_depth(juint i) const {
231 assert(i < primary_super_limit(), "oob");
232 Klass* super = _primary_supers[i];
233 assert(super == NULL || super->super_depth() == i, "correct display");
234 return super;
235 }
236
237 // Can this klass be a primary super? False for interfaces and arrays of
238 // interfaces. False also for arrays or classes with long super chains.
239 bool can_be_primary_super() const {
240 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
241 return super_check_offset() != secondary_offset;
242 }
243 virtual bool can_be_primary_super_slow() const;
244
245 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
246 juint super_depth() const {
247 if (!can_be_primary_super()) {
248 return primary_super_limit();
249 } else {
250 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
251 assert(d < primary_super_limit(), "oob");
252 assert(_primary_supers[d] == this, "proper init");
253 return d;
254 }
255 }
256
257 // store an oop into a field of a Klass
258 void klass_oop_store(oop* p, oop v);
259 void klass_oop_store(volatile oop* p, oop v);
260
261 // java mirror
262 oop java_mirror() const { return _java_mirror; }
263 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); }
264
265 // modifier flags
266 jint modifier_flags() const { return _modifier_flags; }
267 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
268
269 // size helper
270 int layout_helper() const { return _layout_helper; }
271 void set_layout_helper(int lh) { _layout_helper = lh; }
272
273 // Note: for instances layout_helper() may include padding.
274 // Use InstanceKlass::contains_field_offset to classify field offsets.
275
276 // sub/superklass links
277 InstanceKlass* superklass() const;
278 Klass* subklass() const;
279 Klass* next_sibling() const;
280 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
281
282 void set_next_link(Klass* k) { _next_link = k; }
283 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
284
285 // class loader data
286 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
287 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
288
289 // The Klasses are not placed in the Heap, so the Card Table or
290 // the Mod Union Table can't be used to mark when klasses have modified oops.
291 // The CT and MUT bits saves this information for the individual Klasses.
292 void record_modified_oops() { _modified_oops = 1; }
293 void clear_modified_oops() { _modified_oops = 0; }
294 bool has_modified_oops() { return _modified_oops == 1; }
295
296 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; }
297 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; }
298 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; }
299
300 int shared_classpath_index() const {
301 return _shared_class_path_index;
302 };
303
304 void set_shared_classpath_index(int index) {
305 _shared_class_path_index = index;
306 };
307
308
309 protected: // internal accessors
310 Klass* subklass_oop() const { return _subklass; }
311 Klass* next_sibling_oop() const { return _next_sibling; }
312 void set_subklass(Klass* s);
313 void set_next_sibling(Klass* s);
314
315 public:
316
317 // Compiler support
318 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
319 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
320 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
321 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
322 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
323 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
324 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
325 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
326 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
327
328 // Unpacking layout_helper:
329 enum {
330 _lh_neutral_value = 0, // neutral non-array non-instance value
331 _lh_instance_slow_path_bit = 0x01,
332 _lh_log2_element_size_shift = BitsPerByte*0,
333 _lh_log2_element_size_mask = BitsPerLong-1,
334 _lh_element_type_shift = BitsPerByte*1,
335 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
336 _lh_header_size_shift = BitsPerByte*2,
337 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
338 _lh_array_tag_bits = 2,
339 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
340 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
341 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
342 };
343
344 static int layout_helper_size_in_bytes(jint lh) {
345 assert(lh > (jint)_lh_neutral_value, "must be instance");
346 return (int) lh & ~_lh_instance_slow_path_bit;
347 }
348 static bool layout_helper_needs_slow_path(jint lh) {
349 assert(lh > (jint)_lh_neutral_value, "must be instance");
350 return (lh & _lh_instance_slow_path_bit) != 0;
351 }
352 static bool layout_helper_is_instance(jint lh) {
353 return (jint)lh > (jint)_lh_neutral_value;
354 }
355 static bool layout_helper_is_array(jint lh) {
356 return (jint)lh < (jint)_lh_neutral_value;
357 }
358 static bool layout_helper_is_typeArray(jint lh) {
359 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
360 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
361 }
362 static bool layout_helper_is_objArray(jint lh) {
363 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
364 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
365 }
366 static int layout_helper_header_size(jint lh) {
367 assert(lh < (jint)_lh_neutral_value, "must be array");
368 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
369 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
370 return hsize;
371 }
372 static BasicType layout_helper_element_type(jint lh) {
373 assert(lh < (jint)_lh_neutral_value, "must be array");
374 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
375 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
376 return (BasicType) btvalue;
377 }
378
379 // Want a pattern to quickly diff against layout header in register
380 // find something less clever!
381 static int layout_helper_boolean_diffbit() {
382 jint zlh = array_layout_helper(T_BOOLEAN);
383 jint blh = array_layout_helper(T_BYTE);
384 assert(zlh != blh, "array layout helpers must differ");
385 int diffbit = 1;
386 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
387 diffbit <<= 1;
388 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
389 }
390 return diffbit;
391 }
392
393 static int layout_helper_log2_element_size(jint lh) {
394 assert(lh < (jint)_lh_neutral_value, "must be array");
395 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
396 assert(l2esz <= LogBitsPerLong,
397 err_msg("sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh));
398 return l2esz;
399 }
400 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
401 return (tag << _lh_array_tag_shift)
402 | (hsize << _lh_header_size_shift)
403 | ((int)etype << _lh_element_type_shift)
404 | (log2_esize << _lh_log2_element_size_shift);
405 }
406 static jint instance_layout_helper(jint size, bool slow_path_flag) {
407 return (size << LogHeapWordSize)
408 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
409 }
410 static int layout_helper_to_size_helper(jint lh) {
411 assert(lh > (jint)_lh_neutral_value, "must be instance");
412 // Note that the following expression discards _lh_instance_slow_path_bit.
413 return lh >> LogHeapWordSize;
414 }
415 // Out-of-line version computes everything based on the etype:
416 static jint array_layout_helper(BasicType etype);
417
418 // What is the maximum number of primary superclasses any klass can have?
419 #ifdef PRODUCT
420 static juint primary_super_limit() { return _primary_super_limit; }
421 #else
422 static juint primary_super_limit() {
423 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
424 return FastSuperclassLimit;
425 }
426 #endif
427
428 // vtables
429 virtual klassVtable* vtable() const { return NULL; }
430 virtual int vtable_length() const { return 0; }
431
432 // subclass check
433 bool is_subclass_of(const Klass* k) const;
434 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
435 bool is_subtype_of(Klass* k) const {
436 juint off = k->super_check_offset();
437 Klass* sup = *(Klass**)( (address)this + off );
438 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
439 if (sup == k) {
440 return true;
441 } else if (off != secondary_offset) {
442 return false;
443 } else {
444 return search_secondary_supers(k);
445 }
446 }
447 bool search_secondary_supers(Klass* k) const;
448
449 // Find LCA in class hierarchy
450 Klass *LCA( Klass *k );
451
452 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
453 // if not, throw either an Error or an Exception.
454 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
455
456 // array copying
457 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
458
459 // tells if the class should be initialized
460 virtual bool should_be_initialized() const { return false; }
461 // initializes the klass
462 virtual void initialize(TRAPS);
463 // lookup operation for MethodLookupCache
464 friend class MethodLookupCache;
465 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
466 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature, OverpassLookupMode overpass_mode) const;
467 public:
468 Method* lookup_method(Symbol* name, Symbol* signature) const {
469 return uncached_lookup_method(name, signature, find_overpass);
470 }
471
472 // array class with specific rank
473 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
474
475 // array class with this klass as element type
476 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
477
478 // These will return NULL instead of allocating on the heap:
479 // NB: these can block for a mutex, like other functions with TRAPS arg.
480 Klass* array_klass_or_null(int rank);
481 Klass* array_klass_or_null();
482
483 virtual oop protection_domain() const = 0;
484
485 oop class_loader() const;
486
487 virtual oop klass_holder() const { return class_loader(); }
488
489 protected:
490 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
491 virtual Klass* array_klass_impl(bool or_null, TRAPS);
492
493 public:
494 // CDS support - remove and restore oops from metadata. Oops are not shared.
495 virtual void remove_unshareable_info();
496 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
497
498 protected:
499 // computes the subtype relationship
500 virtual bool compute_is_subtype_of(Klass* k);
501 public:
502 // subclass accessor (here for convenience; undefined for non-klass objects)
503 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
504 public:
505 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
506 // These functions describe behavior for the oop not the KLASS.
507
508 // actual oop size of obj in memory
509 virtual int oop_size(oop obj) const = 0;
510
511 // Size of klass in word size.
512 virtual int size() const = 0;
513 #if INCLUDE_SERVICES
514 virtual void collect_statistics(KlassSizeStats *sz) const;
515 #endif
516
517 // Returns the Java name for a class (Resource allocated)
518 // For arrays, this returns the name of the element with a leading '['.
519 // For classes, this returns the name with the package separators
520 // turned into '.'s.
521 const char* external_name() const;
522 // Returns the name for a class (Resource allocated) as the class
523 // would appear in a signature.
524 // For arrays, this returns the name of the element with a leading '['.
525 // For classes, this returns the name with a leading 'L' and a trailing ';'
526 // and the package separators as '/'.
527 virtual const char* signature_name() const;
528
529 // garbage collection support
530 virtual void oop_follow_contents(oop obj) = 0;
531 virtual int oop_adjust_pointers(oop obj) = 0;
532
533 // Parallel Scavenge and Parallel Old
534 PARALLEL_GC_DECLS_PV
535
536 // type testing operations
537 protected:
538 virtual bool oop_is_instance_slow() const { return false; }
539 virtual bool oop_is_array_slow() const { return false; }
540 virtual bool oop_is_objArray_slow() const { return false; }
541 virtual bool oop_is_typeArray_slow() const { return false; }
542 public:
543 virtual bool oop_is_instanceClassLoader() const { return false; }
544 virtual bool oop_is_instanceMirror() const { return false; }
545 virtual bool oop_is_instanceRef() const { return false; }
546
547 // Fast non-virtual versions
548 #ifndef ASSERT
549 #define assert_same_query(xval, xcheck) xval
550 #else
551 private:
552 static bool assert_same_query(bool xval, bool xslow) {
553 assert(xval == xslow, "slow and fast queries agree");
554 return xval;
555 }
556 public:
557 #endif
558 inline bool oop_is_instance() const { return assert_same_query(
559 layout_helper_is_instance(layout_helper()),
560 oop_is_instance_slow()); }
561 inline bool oop_is_array() const { return assert_same_query(
562 layout_helper_is_array(layout_helper()),
563 oop_is_array_slow()); }
564 inline bool oop_is_objArray() const { return assert_same_query(
565 layout_helper_is_objArray(layout_helper()),
566 oop_is_objArray_slow()); }
567 inline bool oop_is_typeArray() const { return assert_same_query(
568 layout_helper_is_typeArray(layout_helper()),
569 oop_is_typeArray_slow()); }
570 #undef assert_same_query
571
572 // Access flags
573 AccessFlags access_flags() const { return _access_flags; }
574 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
575
576 bool is_public() const { return _access_flags.is_public(); }
577 bool is_final() const { return _access_flags.is_final(); }
578 bool is_interface() const { return _access_flags.is_interface(); }
579 bool is_abstract() const { return _access_flags.is_abstract(); }
580 bool is_super() const { return _access_flags.is_super(); }
581 bool is_synthetic() const { return _access_flags.is_synthetic(); }
582 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
583 bool has_finalizer() const { return _access_flags.has_finalizer(); }
584 bool has_final_method() const { return _access_flags.has_final_method(); }
585 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
586 void set_has_final_method() { _access_flags.set_has_final_method(); }
587 bool is_cloneable() const;
588 void set_is_cloneable();
589 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
590 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
591 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
592 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
593
594 // Biased locking support
595 // Note: the prototype header is always set up to be at least the
596 // prototype markOop. If biased locking is enabled it may further be
597 // biasable and have an epoch.
598 markOop prototype_header() const { return _prototype_header; }
599 // NOTE: once instances of this klass are floating around in the
600 // system, this header must only be updated at a safepoint.
601 // NOTE 2: currently we only ever set the prototype header to the
602 // biasable prototype for instanceKlasses. There is no technical
603 // reason why it could not be done for arrayKlasses aside from
604 // wanting to reduce the initial scope of this optimization. There
605 // are potential problems in setting the bias pattern for
606 // JVM-internal oops.
607 inline void set_prototype_header(markOop header);
608 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
609
610 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
611 // Atomically increments biased_lock_revocation_count and returns updated value
612 int atomic_incr_biased_lock_revocation_count();
613 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
614 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
615 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
616
617 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
618
619 // garbage collection support
620 virtual void oops_do(OopClosure* cl);
621
622 // Iff the class loader (or mirror for anonymous classes) is alive the
623 // Klass is considered alive.
624 // The is_alive closure passed in depends on the Garbage Collector used.
625 bool is_loader_alive(BoolObjectClosure* is_alive);
626
627 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true);
628 static void clean_subklass_tree(BoolObjectClosure* is_alive) {
629 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */);
630 }
631
632 // iterators
633 virtual int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) = 0;
634 virtual int oop_oop_iterate_v(oop obj, ExtendedOopClosure* blk) {
635 return oop_oop_iterate(obj, blk);
636 }
637
638 #if INCLUDE_ALL_GCS
639 // In case we don't have a specialized backward scanner use forward
640 // iteration.
641 virtual int oop_oop_iterate_backwards_v(oop obj, ExtendedOopClosure* blk) {
642 return oop_oop_iterate_v(obj, blk);
643 }
644 #endif // INCLUDE_ALL_GCS
645
646 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
647 // (I don't see why the _m should be required, but without it the Solaris
648 // C++ gives warning messages about overridings of the "oop_oop_iterate"
649 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */
650 virtual int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) = 0;
651 virtual int oop_oop_iterate_v_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
652 return oop_oop_iterate_m(obj, blk, mr);
653 }
654
655 // Versions of the above iterators specialized to particular subtypes
656 // of OopClosure, to avoid closure virtual calls.
657 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
658 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \
659 /* Default implementation reverts to general version. */ \
660 return oop_oop_iterate(obj, blk); \
661 } \
662 \
663 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
664 (I don't see why the _m should be required, but without it the Solaris \
665 C++ gives warning messages about overridings of the "oop_oop_iterate" \
666 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \
667 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \
668 OopClosureType* blk, \
669 MemRegion mr) { \
670 return oop_oop_iterate_m(obj, blk, mr); \
671 }
672
673 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
674 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
675
676 #if INCLUDE_ALL_GCS
677 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
678 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \
679 OopClosureType* blk) { \
680 /* Default implementation reverts to general version. */ \
681 return oop_oop_iterate_backwards_v(obj, blk); \
682 }
683
684 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
685 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
686 #endif // INCLUDE_ALL_GCS
687
688 virtual void array_klasses_do(void f(Klass* k)) {}
689
690 // Return self, except for abstract classes with exactly 1
691 // implementor. Then return the 1 concrete implementation.
692 Klass *up_cast_abstract();
693
694 // klass name
695 Symbol* name() const { return _name; }
696 void set_name(Symbol* n);
697
698 public:
699 // jvm support
700 virtual jint compute_modifier_flags(TRAPS) const;
701
702 // JVMTI support
703 virtual jint jvmti_class_status() const;
704
705 // Printing
706 virtual void print_on(outputStream* st) const;
707
708 virtual void oop_print_value_on(oop obj, outputStream* st);
709 virtual void oop_print_on (oop obj, outputStream* st);
710
711 virtual const char* internal_name() const = 0;
712
713 // Verification
714 virtual void verify_on(outputStream* st);
715 void verify() { verify_on(tty); }
716
717 #ifndef PRODUCT
718 bool verify_vtable_index(int index);
719 bool verify_itable_index(int index);
720 #endif
721
722 virtual void oop_verify_on(oop obj, outputStream* st);
723
724 static bool is_null(narrowKlass obj);
725 static bool is_null(Klass* obj);
726
727 // klass encoding for klass pointer in objects.
728 static narrowKlass encode_klass_not_null(Klass* v);
729 static narrowKlass encode_klass(Klass* v);
730
731 static Klass* decode_klass_not_null(narrowKlass v);
732 static Klass* decode_klass(narrowKlass v);
733
734 private:
735 // barriers used by klass_oop_store
736 void klass_update_barrier_set(oop v);
737 void klass_update_barrier_set_pre(oop* p, oop v);
738 };
739
740 #endif // SHARE_VM_OOPS_KLASS_HPP