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