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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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23 */
24
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
27
28 #include "classfile/classLoaderData.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "oops/metadata.hpp"
32 #include "oops/oop.hpp"
33 #include "oops/oopHandle.hpp"
34 #include "utilities/accessFlags.hpp"
35 #include "utilities/macros.hpp"
36 #if INCLUDE_JFR
37 #include "jfr/support/jfrTraceIdExtension.hpp"
38 #endif
39
40 // Klass IDs for all subclasses of Klass
41 enum KlassID {
42 InstanceKlassID,
43 InstanceRefKlassID,
44 InstanceMirrorKlassID,
45 InstanceClassLoaderKlassID,
46 TypeArrayKlassID,
47 ObjArrayKlassID
48 };
49
50 const uint KLASS_ID_COUNT = 6;
51
52 //
53 // A Klass provides:
54 // 1: language level class object (method dictionary etc.)
55 // 2: provide vm dispatch behavior for the object
56 // Both functions are combined into one C++ class.
57
58 // One reason for the oop/klass dichotomy in the implementation is
59 // that we don't want a C++ vtbl pointer in every object. Thus,
60 // normal oops don't have any virtual functions. Instead, they
61 // forward all "virtual" functions to their klass, which does have
62 // a vtbl and does the C++ dispatch depending on the object's
63 // actual type. (See oop.inline.hpp for some of the forwarding code.)
64 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
65
66 // Forward declarations.
67 template <class T> class Array;
68 template <class T> class GrowableArray;
69 class fieldDescriptor;
70 class KlassSizeStats;
71 class klassVtable;
72 class ModuleEntry;
73 class PackageEntry;
74 class ParCompactionManager;
75 class PSPromotionManager;
76 class vtableEntry;
77
78 class Klass : public Metadata {
79 friend class VMStructs;
80 friend class JVMCIVMStructs;
81 protected:
82 // If you add a new field that points to any metaspace object, you
83 // must add this field to Klass::metaspace_pointers_do().
84
85 // note: put frequently-used fields together at start of klass structure
86 // for better cache behavior (may not make much of a difference but sure won't hurt)
87 enum { _primary_super_limit = 8 };
88
89 // The "layout helper" is a combined descriptor of object layout.
90 // For klasses which are neither instance nor array, the value is zero.
91 //
92 // For instances, layout helper is a positive number, the instance size.
93 // This size is already passed through align_object_size and scaled to bytes.
94 // The low order bit is set if instances of this class cannot be
95 // allocated using the fastpath.
96 //
97 // For arrays, layout helper is a negative number, containing four
98 // distinct bytes, as follows:
99 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
100 // where:
101 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
102 // hsz is array header size in bytes (i.e., offset of first element)
103 // ebt is the BasicType of the elements
104 // esz is the element size in bytes
105 // This packed word is arranged so as to be quickly unpacked by the
106 // various fast paths that use the various subfields.
107 //
108 // The esz bits can be used directly by a SLL instruction, without masking.
109 //
110 // Note that the array-kind tag looks like 0x00 for instance klasses,
111 // since their length in bytes is always less than 24Mb.
112 //
113 // Final note: This comes first, immediately after C++ vtable,
114 // because it is frequently queried.
115 jint _layout_helper;
116
117 // Klass identifier used to implement devirtualized oop closure dispatching.
118 const KlassID _id;
119
120 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
121 // and _primary_supers all help make fast subtype checks. See big discussion
122 // in doc/server_compiler/checktype.txt
123 //
124 // Where to look to observe a supertype (it is &_secondary_super_cache for
125 // secondary supers, else is &_primary_supers[depth()].
126 juint _super_check_offset;
127
128 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
129 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
130 Symbol* _name;
131
132 // Cache of last observed secondary supertype
133 Klass* _secondary_super_cache;
134 // Array of all secondary supertypes
135 Array<Klass*>* _secondary_supers;
136 // Ordered list of all primary supertypes
137 Klass* _primary_supers[_primary_super_limit];
138 // java/lang/Class instance mirroring this class
139 OopHandle _java_mirror;
140 // Superclass
141 Klass* _super;
142 // First subclass (NULL if none); _subklass->next_sibling() is next one
143 Klass* _subklass;
144 // Sibling link (or NULL); links all subklasses of a klass
145 Klass* _next_sibling;
146
147 // All klasses loaded by a class loader are chained through these links
148 Klass* _next_link;
149
150 // The VM's representation of the ClassLoader used to load this class.
151 // Provide access the corresponding instance java.lang.ClassLoader.
152 ClassLoaderData* _class_loader_data;
153
154 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
155 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
156
157 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
158
159 // Biased locking implementation and statistics
160 // (the 64-bit chunk goes first, to avoid some fragmentation)
161 jlong _last_biased_lock_bulk_revocation_time;
162 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
163 jint _biased_lock_revocation_count;
164
165 // vtable length
166 int _vtable_len;
167
168 private:
169 // This is an index into FileMapHeader::_shared_path_table[], to
170 // associate this class with the JAR file where it's loaded from during
171 // dump time. If a class is not loaded from the shared archive, this field is
172 // -1.
173 jshort _shared_class_path_index;
174
175 #if INCLUDE_CDS
176 // Flags of the current shared class.
177 u2 _shared_class_flags;
178 enum {
179 _has_raw_archived_mirror = 1,
180 _has_signer_and_not_archived = 1 << 2
181 };
182 #endif
183 // The _archived_mirror is set at CDS dump time pointing to the cached mirror
184 // in the open archive heap region when archiving java object is supported.
185 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;)
186
187 protected:
188
189 // Constructor
190 Klass(KlassID id);
191 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
192
193 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
194
195 public:
196 int id() { return _id; }
197
198 enum DefaultsLookupMode { find_defaults, skip_defaults };
199 enum OverpassLookupMode { find_overpass, skip_overpass };
200 enum StaticLookupMode { find_static, skip_static };
201 enum PrivateLookupMode { find_private, skip_private };
202
203 bool is_klass() const volatile { return true; }
204
205 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
206 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
207 // If this is not what your code expects, you're probably looking for Klass::java_super().
208 Klass* super() const { return _super; }
209 void set_super(Klass* k) { _super = k; }
210
211 // initializes _super link, _primary_supers & _secondary_supers arrays
212 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
213
214 // klass-specific helper for initializing _secondary_supers
215 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
216 Array<InstanceKlass*>* transitive_interfaces);
217
218 // java_super is the Java-level super type as specified by Class.getSuperClass.
219 virtual InstanceKlass* java_super() const { return NULL; }
220
221 juint super_check_offset() const { return _super_check_offset; }
222 void set_super_check_offset(juint o) { _super_check_offset = o; }
223
224 Klass* secondary_super_cache() const { return _secondary_super_cache; }
225 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
226
227 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
228 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
229
230 // Return the element of the _super chain of the given depth.
231 // If there is no such element, return either NULL or this.
232 Klass* primary_super_of_depth(juint i) const {
233 assert(i < primary_super_limit(), "oob");
234 Klass* super = _primary_supers[i];
235 assert(super == NULL || super->super_depth() == i, "correct display");
236 return super;
237 }
238
239 // Can this klass be a primary super? False for interfaces and arrays of
240 // interfaces. False also for arrays or classes with long super chains.
241 bool can_be_primary_super() const {
242 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
243 return super_check_offset() != secondary_offset;
244 }
245 virtual bool can_be_primary_super_slow() const;
246
247 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
248 juint super_depth() const {
249 if (!can_be_primary_super()) {
250 return primary_super_limit();
251 } else {
252 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
253 assert(d < primary_super_limit(), "oob");
254 assert(_primary_supers[d] == this, "proper init");
255 return d;
256 }
257 }
258
259 // java mirror
260 oop java_mirror() const;
261 void set_java_mirror(Handle m);
262
263 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier
264 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier
265
266 // Temporary mirror switch used by RedefineClasses
267 // Both mirrors are on the ClassLoaderData::_handles list already so no
268 // barriers are needed.
269 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; }
270 OopHandle java_mirror_handle() const {
271 return _java_mirror;
272 }
273
274 // modifier flags
275 jint modifier_flags() const { return _modifier_flags; }
276 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
277
278 // size helper
279 int layout_helper() const { return _layout_helper; }
280 void set_layout_helper(int lh) { _layout_helper = lh; }
281
282 // Note: for instances layout_helper() may include padding.
283 // Use InstanceKlass::contains_field_offset to classify field offsets.
284
285 // sub/superklass links
286 Klass* subklass() const { return _subklass; }
287 Klass* next_sibling() const { return _next_sibling; }
288 InstanceKlass* superklass() const;
289 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
290
291 void set_next_link(Klass* k) { _next_link = k; }
292 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
293
294 // class loader data
295 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
296 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
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 void set_has_raw_archived_mirror() {
307 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;)
308 }
309 void clear_has_raw_archived_mirror() {
310 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;)
311 }
312 bool has_raw_archived_mirror() const {
313 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;)
314 NOT_CDS(return false;)
315 }
316 #if INCLUDE_CDS
317 void set_has_signer_and_not_archived() {
318 _shared_class_flags |= _has_signer_and_not_archived;
319 }
320 bool has_signer_and_not_archived() const {
321 assert(DumpSharedSpaces, "dump time only");
322 return (_shared_class_flags & _has_signer_and_not_archived) != 0;
323 }
324 #endif // INCLUDE_CDS
325
326 // Obtain the module or package for this class
327 virtual ModuleEntry* module() const = 0;
328 virtual PackageEntry* package() const = 0;
329
330 protected: // internal accessors
331 void set_subklass(Klass* s);
332 void set_next_sibling(Klass* s);
333
334 public:
335
336 // Compiler support
337 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
338 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
339 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
340 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
341 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
342 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
343 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
344 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
345 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
346
347 // Unpacking layout_helper:
348 enum {
349 _lh_neutral_value = 0, // neutral non-array non-instance value
350 _lh_instance_slow_path_bit = 0x01,
351 _lh_log2_element_size_shift = BitsPerByte*0,
352 _lh_log2_element_size_mask = BitsPerLong-1,
353 _lh_element_type_shift = BitsPerByte*1,
354 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
355 _lh_header_size_shift = BitsPerByte*2,
356 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
357 _lh_array_tag_bits = 2,
358 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
359 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
360 };
361
362 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
363
364 static int layout_helper_size_in_bytes(jint lh) {
365 assert(lh > (jint)_lh_neutral_value, "must be instance");
366 return (int) lh & ~_lh_instance_slow_path_bit;
367 }
368 static bool layout_helper_needs_slow_path(jint lh) {
369 assert(lh > (jint)_lh_neutral_value, "must be instance");
370 return (lh & _lh_instance_slow_path_bit) != 0;
371 }
372 static bool layout_helper_is_instance(jint lh) {
373 return (jint)lh > (jint)_lh_neutral_value;
374 }
375 static bool layout_helper_is_array(jint lh) {
376 return (jint)lh < (jint)_lh_neutral_value;
377 }
378 static bool layout_helper_is_typeArray(jint lh) {
379 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
380 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
381 }
382 static bool layout_helper_is_objArray(jint lh) {
383 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
384 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
385 }
386 static int layout_helper_header_size(jint lh) {
387 assert(lh < (jint)_lh_neutral_value, "must be array");
388 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
389 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
390 return hsize;
391 }
392 static BasicType layout_helper_element_type(jint lh) {
393 assert(lh < (jint)_lh_neutral_value, "must be array");
394 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
395 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
396 return (BasicType) btvalue;
397 }
398
399 // Want a pattern to quickly diff against layout header in register
400 // find something less clever!
401 static int layout_helper_boolean_diffbit() {
402 jint zlh = array_layout_helper(T_BOOLEAN);
403 jint blh = array_layout_helper(T_BYTE);
404 assert(zlh != blh, "array layout helpers must differ");
405 int diffbit = 1;
406 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
407 diffbit <<= 1;
408 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
409 }
410 return diffbit;
411 }
412
413 static int layout_helper_log2_element_size(jint lh) {
414 assert(lh < (jint)_lh_neutral_value, "must be array");
415 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
416 assert(l2esz <= LogBytesPerLong,
417 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
418 return l2esz;
419 }
420 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
421 return (tag << _lh_array_tag_shift)
422 | (hsize << _lh_header_size_shift)
423 | ((int)etype << _lh_element_type_shift)
424 | (log2_esize << _lh_log2_element_size_shift);
425 }
426 static jint instance_layout_helper(jint size, bool slow_path_flag) {
427 return (size << LogBytesPerWord)
428 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
429 }
430 static int layout_helper_to_size_helper(jint lh) {
431 assert(lh > (jint)_lh_neutral_value, "must be instance");
432 // Note that the following expression discards _lh_instance_slow_path_bit.
433 return lh >> LogBytesPerWord;
434 }
435 // Out-of-line version computes everything based on the etype:
436 static jint array_layout_helper(BasicType etype);
437
438 // What is the maximum number of primary superclasses any klass can have?
439 #ifdef PRODUCT
440 static juint primary_super_limit() { return _primary_super_limit; }
441 #else
442 static juint primary_super_limit() {
443 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
444 return FastSuperclassLimit;
445 }
446 #endif
447
448 // vtables
449 klassVtable vtable() const;
450 int vtable_length() const { return _vtable_len; }
451
452 // subclass check
453 bool is_subclass_of(const Klass* k) const;
454 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
455 bool is_subtype_of(Klass* k) const {
456 juint off = k->super_check_offset();
457 Klass* sup = *(Klass**)( (address)this + off );
458 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
459 if (sup == k) {
460 return true;
461 } else if (off != secondary_offset) {
462 return false;
463 } else {
464 return search_secondary_supers(k);
465 }
466 }
467
468 bool search_secondary_supers(Klass* k) const;
469
470 // Find LCA in class hierarchy
471 Klass *LCA( Klass *k );
472
473 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
474 // if not, throw either an Error or an Exception.
475 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
476
477 // array copying
478 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
479
480 // tells if the class should be initialized
481 virtual bool should_be_initialized() const { return false; }
482 // initializes the klass
483 virtual void initialize(TRAPS);
484 // lookup operation for MethodLookupCache
485 friend class MethodLookupCache;
486 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
487 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature,
488 OverpassLookupMode overpass_mode,
489 PrivateLookupMode = find_private) const;
490 public:
491 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
492 return uncached_lookup_method(name, signature, find_overpass);
493 }
494
495 // array class with specific rank
496 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
497
498 // array class with this klass as element type
499 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
500
501 // These will return NULL instead of allocating on the heap:
502 // NB: these can block for a mutex, like other functions with TRAPS arg.
503 Klass* array_klass_or_null(int rank);
504 Klass* array_klass_or_null();
505
506 virtual oop protection_domain() const = 0;
507
508 oop class_loader() const;
509
510 virtual oop klass_holder() const { return class_loader(); }
511
512 protected:
513 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
514 virtual Klass* array_klass_impl(bool or_null, TRAPS);
515
516 void set_vtable_length(int len) { _vtable_len= len; }
517
518 vtableEntry* start_of_vtable() const;
519 public:
520 Method* method_at_vtable(int index);
521
522 static ByteSize vtable_start_offset();
523 static ByteSize vtable_length_offset() {
524 return byte_offset_of(Klass, _vtable_len);
525 }
526
527 // CDS support - remove and restore oops from metadata. Oops are not shared.
528 virtual void remove_unshareable_info();
529 virtual void remove_java_mirror();
530 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
531
532 protected:
533 // computes the subtype relationship
534 virtual bool compute_is_subtype_of(Klass* k);
535 public:
536 // subclass accessor (here for convenience; undefined for non-klass objects)
537 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
538 public:
539 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
540 // These functions describe behavior for the oop not the KLASS.
541
542 // actual oop size of obj in memory
543 virtual int oop_size(oop obj) const = 0;
544
545 // Size of klass in word size.
546 virtual int size() const = 0;
547 #if INCLUDE_SERVICES
548 virtual void collect_statistics(KlassSizeStats *sz) const;
549 #endif
550
551 // Returns the Java name for a class (Resource allocated)
552 // For arrays, this returns the name of the element with a leading '['.
553 // For classes, this returns the name with the package separators
554 // turned into '.'s.
555 const char* external_name() const;
556 // Returns the name for a class (Resource allocated) as the class
557 // would appear in a signature.
558 // For arrays, this returns the name of the element with a leading '['.
559 // For classes, this returns the name with a leading 'L' and a trailing ';'
560 // and the package separators as '/'.
561 virtual const char* signature_name() const;
562
563 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
564 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
565
566 // Returns "interface", "abstract class" or "class".
567 const char* external_kind() const;
568
569 // type testing operations
570 #ifdef ASSERT
571 protected:
572 virtual bool is_instance_klass_slow() const { return false; }
573 virtual bool is_array_klass_slow() const { return false; }
574 virtual bool is_objArray_klass_slow() const { return false; }
575 virtual bool is_typeArray_klass_slow() const { return false; }
576 #endif // ASSERT
577 public:
578
579 // Fast non-virtual versions
580 #ifndef ASSERT
581 #define assert_same_query(xval, xcheck) xval
582 #else
583 private:
584 static bool assert_same_query(bool xval, bool xslow) {
585 assert(xval == xslow, "slow and fast queries agree");
586 return xval;
587 }
588 public:
589 #endif
590 inline bool is_instance_klass() const { return assert_same_query(
591 layout_helper_is_instance(layout_helper()),
592 is_instance_klass_slow()); }
593 inline bool is_array_klass() const { return assert_same_query(
594 layout_helper_is_array(layout_helper()),
595 is_array_klass_slow()); }
596 inline bool is_objArray_klass() const { return assert_same_query(
597 layout_helper_is_objArray(layout_helper()),
598 is_objArray_klass_slow()); }
599 inline bool is_typeArray_klass() const { return assert_same_query(
600 layout_helper_is_typeArray(layout_helper()),
601 is_typeArray_klass_slow()); }
602 #undef assert_same_query
603
604 // Access flags
605 AccessFlags access_flags() const { return _access_flags; }
606 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
607
608 bool is_public() const { return _access_flags.is_public(); }
609 bool is_final() const { return _access_flags.is_final(); }
610 bool is_interface() const { return _access_flags.is_interface(); }
611 bool is_abstract() const { return _access_flags.is_abstract(); }
612 bool is_super() const { return _access_flags.is_super(); }
613 bool is_synthetic() const { return _access_flags.is_synthetic(); }
614 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
615 bool has_finalizer() const { return _access_flags.has_finalizer(); }
616 bool has_final_method() const { return _access_flags.has_final_method(); }
617 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
618 void set_has_final_method() { _access_flags.set_has_final_method(); }
619 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
620 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
621 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
622 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
623 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
624 void set_is_shared() { _access_flags.set_is_shared_class(); }
625
626 bool is_cloneable() const;
627 void set_is_cloneable();
628
629 // Biased locking support
630 // Note: the prototype header is always set up to be at least the
631 // prototype markOop. If biased locking is enabled it may further be
632 // biasable and have an epoch.
633 markOop prototype_header() const { return _prototype_header; }
634 // NOTE: once instances of this klass are floating around in the
635 // system, this header must only be updated at a safepoint.
636 // NOTE 2: currently we only ever set the prototype header to the
637 // biasable prototype for instanceKlasses. There is no technical
638 // reason why it could not be done for arrayKlasses aside from
639 // wanting to reduce the initial scope of this optimization. There
640 // are potential problems in setting the bias pattern for
641 // JVM-internal oops.
642 inline void set_prototype_header(markOop header);
643 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
644
645 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
646 // Atomically increments biased_lock_revocation_count and returns updated value
647 int atomic_incr_biased_lock_revocation_count();
648 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
649 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
650 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
651
652 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
653
654 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
655 virtual MetaspaceObj::Type type() const { return ClassType; }
656
657 // Iff the class loader (or mirror for anonymous classes) is alive the
658 // Klass is considered alive. Has already been marked as unloading.
659 bool is_loader_alive() const { return class_loader_data() == NULL || class_loader_data()->is_alive(); }
660
661 // Load the klass's holder as a phantom. This is useful when a weak Klass
662 // pointer has been "peeked" and then must be kept alive before it may
663 // be used safely.
664 oop holder_phantom() const;
665
666 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
667 static void clean_subklass_tree() {
668 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
669 }
670
671 // GC specific object visitors
672 //
673 #if INCLUDE_PARALLELGC
674 // Parallel Scavenge
675 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0;
676 // Parallel Compact
677 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0;
678 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0;
679 #endif
680
681 virtual void array_klasses_do(void f(Klass* k)) {}
682
683 // Return self, except for abstract classes with exactly 1
684 // implementor. Then return the 1 concrete implementation.
685 Klass *up_cast_abstract();
686
687 // klass name
688 Symbol* name() const { return _name; }
689 void set_name(Symbol* n);
690
691 public:
692 // jvm support
693 virtual jint compute_modifier_flags(TRAPS) const;
694
695 // JVMTI support
696 virtual jint jvmti_class_status() const;
697
698 // Printing
699 virtual void print_on(outputStream* st) const;
700
701 virtual void oop_print_value_on(oop obj, outputStream* st);
702 virtual void oop_print_on (oop obj, outputStream* st);
703
704 virtual const char* internal_name() const = 0;
705
706 // Verification
707 virtual void verify_on(outputStream* st);
708 void verify() { verify_on(tty); }
709
710 #ifndef PRODUCT
711 bool verify_vtable_index(int index);
712 #endif
713
714 virtual void oop_verify_on(oop obj, outputStream* st);
715
716 static bool is_null(narrowKlass obj);
717 static bool is_null(Klass* obj);
718
719 // klass encoding for klass pointer in objects.
720 static narrowKlass encode_klass_not_null(Klass* v);
721 static narrowKlass encode_klass(Klass* v);
722
723 static Klass* decode_klass_not_null(narrowKlass v);
724 static Klass* decode_klass(narrowKlass v);
725 };
726
727 #endif // SHARE_VM_OOPS_KLASS_HPP