1 /*
2 * Copyright (c) 1997, 2020, 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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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
21 * questions.
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23 */
24
25 #ifndef SHARE_OOPS_KLASS_HPP
26 #define SHARE_OOPS_KLASS_HPP
27
28 #include "classfile/classLoaderData.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "oops/markWord.hpp"
32 #include "oops/metadata.hpp"
33 #include "oops/oop.hpp"
34 #include "oops/oopHandle.hpp"
35 #include "utilities/accessFlags.hpp"
36 #include "utilities/macros.hpp"
37 #if INCLUDE_JFR
38 #include "jfr/support/jfrTraceIdExtension.hpp"
39 #endif
40
41 // Klass IDs for all subclasses of Klass
42 enum KlassID {
43 InstanceKlassID,
44 InstanceRefKlassID,
45 InstanceMirrorKlassID,
46 InstanceClassLoaderKlassID,
47 TypeArrayKlassID,
48 ObjArrayKlassID
49 };
50
51 const uint KLASS_ID_COUNT = 6;
52
53 //
54 // A Klass provides:
55 // 1: language level class object (method dictionary etc.)
56 // 2: provide vm dispatch behavior for the object
57 // Both functions are combined into one C++ class.
58
59 // One reason for the oop/klass dichotomy in the implementation is
60 // that we don't want a C++ vtbl pointer in every object. Thus,
61 // normal oops don't have any virtual functions. Instead, they
62 // forward all "virtual" functions to their klass, which does have
63 // a vtbl and does the C++ dispatch depending on the object's
64 // actual type. (See oop.inline.hpp for some of the forwarding code.)
65 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
66
67 // Forward declarations.
68 template <class T> class Array;
69 template <class T> class GrowableArray;
70 class fieldDescriptor;
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* volatile _subklass;
144 // Sibling link (or NULL); links all subklasses of a klass
145 Klass* volatile _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 markWord _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 };
181 #endif
182 // The _archived_mirror is set at CDS dump time pointing to the cached mirror
183 // in the open archive heap region when archiving java object is supported.
184 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;)
185
186 protected:
187
188 // Constructor
189 Klass(KlassID id);
190 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
191
192 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
193
194 public:
195 int id() { return _id; }
196
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() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
205 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
206 // If this is not what your code expects, you're probably looking for Klass::java_super().
207 Klass* super() const { return _super; }
208 void set_super(Klass* k) { _super = k; }
209
210 // initializes _super link, _primary_supers & _secondary_supers arrays
211 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
212
213 // klass-specific helper for initializing _secondary_supers
214 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
215 Array<InstanceKlass*>* transitive_interfaces);
216
217 // java_super is the Java-level super type as specified by Class.getSuperClass.
218 virtual InstanceKlass* java_super() const { return NULL; }
219
220 juint super_check_offset() const { return _super_check_offset; }
221 void set_super_check_offset(juint o) { _super_check_offset = o; }
222
223 Klass* secondary_super_cache() const { return _secondary_super_cache; }
224 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
225
226 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
227 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
228
229 // Return the element of the _super chain of the given depth.
230 // If there is no such element, return either NULL or this.
231 Klass* primary_super_of_depth(juint i) const {
232 assert(i < primary_super_limit(), "oob");
233 Klass* super = _primary_supers[i];
234 assert(super == NULL || super->super_depth() == i, "correct display");
235 return super;
236 }
237
238 // Can this klass be a primary super? False for interfaces and arrays of
239 // interfaces. False also for arrays or classes with long super chains.
240 bool can_be_primary_super() const {
241 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
242 return super_check_offset() != secondary_offset;
243 }
244 virtual bool can_be_primary_super_slow() const;
245
246 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
247 juint super_depth() const {
248 if (!can_be_primary_super()) {
249 return primary_super_limit();
250 } else {
251 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
252 assert(d < primary_super_limit(), "oob");
253 assert(_primary_supers[d] == this, "proper init");
254 return d;
255 }
256 }
257
258 // java mirror
259 oop java_mirror() const;
260 oop java_mirror_no_keepalive() 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 narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(0); // no GC barrier
265 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier
266
267 // Temporary mirror switch used by RedefineClasses
268 // Both mirrors are on the ClassLoaderData::_handles list already so no
269 // barriers are needed.
270 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; }
271 OopHandle java_mirror_handle() const {
272 return _java_mirror;
273 }
274
275 // modifier flags
276 jint modifier_flags() const { return _modifier_flags; }
277 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
278
279 // size helper
280 int layout_helper() const { return _layout_helper; }
281 void set_layout_helper(int lh) { _layout_helper = lh; }
282
283 // Note: for instances layout_helper() may include padding.
284 // Use InstanceKlass::contains_field_offset to classify field offsets.
285
286 // sub/superklass links
287 Klass* subklass(bool log = false) const;
288 Klass* next_sibling(bool log = false) const;
289
290 InstanceKlass* superklass() const;
291 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
292
293 void set_next_link(Klass* k) { _next_link = k; }
294 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
295
296 // class loader data
297 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
298 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
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 void set_has_raw_archived_mirror() {
309 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;)
310 }
311 void clear_has_raw_archived_mirror() {
312 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;)
313 }
314 bool has_raw_archived_mirror() const {
315 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;)
316 NOT_CDS(return false;)
317 }
318
319 // Obtain the module or package for this class
320 virtual ModuleEntry* module() const = 0;
321 virtual PackageEntry* package() const = 0;
322
323 protected: // internal accessors
324 void set_subklass(Klass* s);
325 void set_next_sibling(Klass* s);
326
327 public:
328
329 // Compiler support
330 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
331 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
332 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
333 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
334 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
335 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
336 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
337 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
338 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
339 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
340
341 // Unpacking layout_helper:
342 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
343 static const int _lh_instance_slow_path_bit = 0x01;
344 static const int _lh_log2_element_size_shift = BitsPerByte*0;
345 static const int _lh_log2_element_size_mask = BitsPerLong-1;
346 static const int _lh_element_type_shift = BitsPerByte*1;
347 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
348 static const int _lh_header_size_shift = BitsPerByte*2;
349 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
350 static const int _lh_array_tag_bits = 2;
351 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
352 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30
353
354 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
355
356 static int layout_helper_size_in_bytes(jint lh) {
357 assert(lh > (jint)_lh_neutral_value, "must be instance");
358 return (int) lh & ~_lh_instance_slow_path_bit;
359 }
360 static bool layout_helper_needs_slow_path(jint lh) {
361 assert(lh > (jint)_lh_neutral_value, "must be instance");
362 return (lh & _lh_instance_slow_path_bit) != 0;
363 }
364 static bool layout_helper_is_instance(jint lh) {
365 return (jint)lh > (jint)_lh_neutral_value;
366 }
367 static bool layout_helper_is_array(jint lh) {
368 return (jint)lh < (jint)_lh_neutral_value;
369 }
370 static bool layout_helper_is_typeArray(jint lh) {
371 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
372 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
373 }
374 static bool layout_helper_is_objArray(jint lh) {
375 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
376 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
377 }
378 static int layout_helper_header_size(jint lh) {
379 assert(lh < (jint)_lh_neutral_value, "must be array");
380 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
381 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
382 return hsize;
383 }
384 static BasicType layout_helper_element_type(jint lh) {
385 assert(lh < (jint)_lh_neutral_value, "must be array");
386 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
387 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
388 return (BasicType) btvalue;
389 }
390
391 // Want a pattern to quickly diff against layout header in register
392 // find something less clever!
393 static int layout_helper_boolean_diffbit() {
394 jint zlh = array_layout_helper(T_BOOLEAN);
395 jint blh = array_layout_helper(T_BYTE);
396 assert(zlh != blh, "array layout helpers must differ");
397 int diffbit = 1;
398 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
399 diffbit <<= 1;
400 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
401 }
402 return diffbit;
403 }
404
405 static int layout_helper_log2_element_size(jint lh) {
406 assert(lh < (jint)_lh_neutral_value, "must be array");
407 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
408 assert(l2esz <= LogBytesPerLong,
409 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
410 return l2esz;
411 }
412 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
413 return (tag << _lh_array_tag_shift)
414 | (hsize << _lh_header_size_shift)
415 | ((int)etype << _lh_element_type_shift)
416 | (log2_esize << _lh_log2_element_size_shift);
417 }
418 static jint instance_layout_helper(jint size, bool slow_path_flag) {
419 return (size << LogBytesPerWord)
420 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
421 }
422 static int layout_helper_to_size_helper(jint lh) {
423 assert(lh > (jint)_lh_neutral_value, "must be instance");
424 // Note that the following expression discards _lh_instance_slow_path_bit.
425 return lh >> LogBytesPerWord;
426 }
427 // Out-of-line version computes everything based on the etype:
428 static jint array_layout_helper(BasicType etype);
429
430 // What is the maximum number of primary superclasses any klass can have?
431 static juint primary_super_limit() { return _primary_super_limit; }
432
433 // vtables
434 klassVtable vtable() const;
435 int vtable_length() const { return _vtable_len; }
436
437 // subclass check
438 bool is_subclass_of(const Klass* k) const;
439 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
440 bool is_subtype_of(Klass* k) const {
441 juint off = k->super_check_offset();
442 Klass* sup = *(Klass**)( (address)this + off );
443 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
444 if (sup == k) {
445 return true;
446 } else if (off != secondary_offset) {
447 return false;
448 } else {
449 return search_secondary_supers(k);
450 }
451 }
452
453 bool search_secondary_supers(Klass* k) const;
454
455 // Find LCA in class hierarchy
456 Klass *LCA( Klass *k );
457
458 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
459 // if not, throw either an Error or an Exception.
460 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
461
462 // array copying
463 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
464
465 // tells if the class should be initialized
466 virtual bool should_be_initialized() const { return false; }
467 // initializes the klass
468 virtual void initialize(TRAPS);
469 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
470 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature,
471 OverpassLookupMode overpass_mode,
472 PrivateLookupMode = find_private) const;
473 public:
474 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
475 return uncached_lookup_method(name, signature, find_overpass);
476 }
477
478 // array class with specific rank
479 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
480
481 // array class with this klass as element type
482 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
483
484 // These will return NULL instead of allocating on the heap:
485 // NB: these can block for a mutex, like other functions with TRAPS arg.
486 Klass* array_klass_or_null(int rank);
487 Klass* array_klass_or_null();
488
489 virtual oop protection_domain() const = 0;
490
491 oop class_loader() const;
492
493 // This loads the klass's holder as a phantom. This is useful when a weak Klass
494 // pointer has been "peeked" and then must be kept alive before it may
495 // be used safely. All uses of klass_holder need to apply the appropriate barriers,
496 // except during GC.
497 oop klass_holder() const { return class_loader_data()->holder_phantom(); }
498
499 protected:
500 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
501 virtual Klass* array_klass_impl(bool or_null, TRAPS);
502
503 // Error handling when length > max_length or length < 0
504 static void check_array_allocation_length(int length, int max_length, TRAPS);
505
506 void set_vtable_length(int len) { _vtable_len= len; }
507
508 vtableEntry* start_of_vtable() const;
509 public:
510 Method* method_at_vtable(int index);
511
512 static ByteSize vtable_start_offset();
513 static ByteSize vtable_length_offset() {
514 return byte_offset_of(Klass, _vtable_len);
515 }
516
517 // CDS support - remove and restore oops from metadata. Oops are not shared.
518 virtual void remove_unshareable_info();
519 virtual void remove_java_mirror();
520 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
521
522 bool is_unshareable_info_restored() const {
523 assert(is_shared(), "use this for shared classes only");
524 if (has_raw_archived_mirror()) {
525 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap
526 return false;
527 } else if (_java_mirror.ptr_raw() == NULL) {
528 return false;
529 } else {
530 return true;
531 }
532 }
533
534 public:
535 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
536 // These functions describe behavior for the oop not the KLASS.
537
538 // actual oop size of obj in memory
539 virtual int oop_size(oop obj) const = 0;
540
541 // Size of klass in word size.
542 virtual int size() const = 0;
543
544 // Returns the Java name for a class (Resource allocated)
545 // For arrays, this returns the name of the element with a leading '['.
546 // For classes, this returns the name with the package separators
547 // turned into '.'s.
548 const char* external_name() const;
549 // Returns the name for a class (Resource allocated) as the class
550 // would appear in a signature.
551 // For arrays, this returns the name of the element with a leading '['.
552 // For classes, this returns the name with a leading 'L' and a trailing ';'
553 // and the package separators as '/'.
554 virtual const char* signature_name() const;
555
556 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
557 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
558
559 // Returns "interface", "abstract class" or "class".
560 const char* external_kind() const;
561
562 // type testing operations
563 #ifdef ASSERT
564 protected:
565 virtual bool is_instance_klass_slow() const { return false; }
566 virtual bool is_array_klass_slow() const { return false; }
567 virtual bool is_objArray_klass_slow() const { return false; }
568 virtual bool is_typeArray_klass_slow() const { return false; }
569 #endif // ASSERT
570 public:
571
572 // Fast non-virtual versions
573 #ifndef ASSERT
574 #define assert_same_query(xval, xcheck) xval
575 #else
576 private:
577 static bool assert_same_query(bool xval, bool xslow) {
578 assert(xval == xslow, "slow and fast queries agree");
579 return xval;
580 }
581 public:
582 #endif
583 inline bool is_instance_klass() const { return assert_same_query(
584 layout_helper_is_instance(layout_helper()),
585 is_instance_klass_slow()); }
586 inline bool is_array_klass() const { return assert_same_query(
587 layout_helper_is_array(layout_helper()),
588 is_array_klass_slow()); }
589 inline bool is_objArray_klass() const { return assert_same_query(
590 layout_helper_is_objArray(layout_helper()),
591 is_objArray_klass_slow()); }
592 inline bool is_typeArray_klass() const { return assert_same_query(
593 layout_helper_is_typeArray(layout_helper()),
594 is_typeArray_klass_slow()); }
595 #undef assert_same_query
596
597 // Access flags
598 AccessFlags access_flags() const { return _access_flags; }
599 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
600
601 bool is_public() const { return _access_flags.is_public(); }
602 bool is_final() const { return _access_flags.is_final(); }
603 bool is_interface() const { return _access_flags.is_interface(); }
604 bool is_abstract() const { return _access_flags.is_abstract(); }
605 bool is_super() const { return _access_flags.is_super(); }
606 bool is_synthetic() const { return _access_flags.is_synthetic(); }
607 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
608 bool has_finalizer() const { return _access_flags.has_finalizer(); }
609 bool has_final_method() const { return _access_flags.has_final_method(); }
610 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
611 void set_has_final_method() { _access_flags.set_has_final_method(); }
612 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
613 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
614 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
615 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
616 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
617 void set_is_shared() { _access_flags.set_is_shared_class(); }
618
619 bool is_cloneable() const;
620 void set_is_cloneable();
621
622 // Biased locking support
623 // Note: the prototype header is always set up to be at least the
624 // prototype markWord. If biased locking is enabled it may further be
625 // biasable and have an epoch.
626 markWord prototype_header() const { return _prototype_header; }
627 // NOTE: once instances of this klass are floating around in the
628 // system, this header must only be updated at a safepoint.
629 // NOTE 2: currently we only ever set the prototype header to the
630 // biasable prototype for instanceKlasses. There is no technical
631 // reason why it could not be done for arrayKlasses aside from
632 // wanting to reduce the initial scope of this optimization. There
633 // are potential problems in setting the bias pattern for
634 // JVM-internal oops.
635 inline void set_prototype_header(markWord header);
636 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
637
638 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
639 // Atomically increments biased_lock_revocation_count and returns updated value
640 int atomic_incr_biased_lock_revocation_count();
641 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
642 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
643 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
644
645 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
646
647 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
648 virtual MetaspaceObj::Type type() const { return ClassType; }
649
650 // Iff the class loader (or mirror for unsafe anonymous classes) is alive the
651 // Klass is considered alive. This is safe to call before the CLD is marked as
652 // unloading, and hence during concurrent class unloading.
653 bool is_loader_alive() const { return class_loader_data()->is_alive(); }
654
655 void clean_subklass();
656
657 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
658 static void clean_subklass_tree() {
659 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
660 }
661
662 virtual void array_klasses_do(void f(Klass* k)) {}
663
664 // Return self, except for abstract classes with exactly 1
665 // implementor. Then return the 1 concrete implementation.
666 Klass *up_cast_abstract();
667
668 // klass name
669 Symbol* name() const { return _name; }
670 void set_name(Symbol* n);
671
672 public:
673 // jvm support
674 virtual jint compute_modifier_flags(TRAPS) const;
675
676 // JVMTI support
677 virtual jint jvmti_class_status() const;
678
679 // Printing
680 virtual void print_on(outputStream* st) const;
681
682 virtual void oop_print_value_on(oop obj, outputStream* st);
683 virtual void oop_print_on (oop obj, outputStream* st);
684
685 virtual const char* internal_name() const = 0;
686
687 // Verification
688 virtual void verify_on(outputStream* st);
689 void verify() { verify_on(tty); }
690
691 #ifndef PRODUCT
692 bool verify_vtable_index(int index);
693 #endif
694
695 virtual void oop_verify_on(oop obj, outputStream* st);
696
697 // for error reporting
698 static bool is_valid(Klass* k);
699 };
700
701 #endif // SHARE_OOPS_KLASS_HPP