1 /*
2 * Copyright (c) 1997, 2019, 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
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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/markOop.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 ValueArrayKlassID,
49 ObjArrayKlassID
50 };
51
52 const uint KLASS_ID_COUNT = 7;
53
54 //
55 // A Klass provides:
56 // 1: language level class object (method dictionary etc.)
57 // 2: provide vm dispatch behavior for the object
58 // Both functions are combined into one C++ class.
59
60 // One reason for the oop/klass dichotomy in the implementation is
61 // that we don't want a C++ vtbl pointer in every object. Thus,
62 // normal oops don't have any virtual functions. Instead, they
63 // forward all "virtual" functions to their klass, which does have
64 // a vtbl and does the C++ dispatch depending on the object's
65 // actual type. (See oop.inline.hpp for some of the forwarding code.)
66 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
67
68 // Forward declarations.
69 template <class T> class Array;
70 template <class T> class GrowableArray;
71 class fieldDescriptor;
72 class KlassSizeStats;
73 class klassVtable;
74 class ModuleEntry;
75 class PackageEntry;
76 class ParCompactionManager;
77 class PSPromotionManager;
78 class vtableEntry;
79
80 class Klass : public Metadata {
81 friend class VMStructs;
82 friend class JVMCIVMStructs;
83 protected:
84 // If you add a new field that points to any metaspace object, you
85 // must add this field to Klass::metaspace_pointers_do().
86
87 // note: put frequently-used fields together at start of klass structure
88 // for better cache behavior (may not make much of a difference but sure won't hurt)
89 enum { _primary_super_limit = 8 };
90
91 // The "layout helper" is a combined descriptor of object layout.
92 // For klasses which are neither instance nor array, the value is zero.
93 //
94 // For instances, layout helper is a positive number, the instance size.
95 // This size is already passed through align_object_size and scaled to bytes.
96 // The low order bit is set if instances of this class cannot be
97 // allocated using the fastpath.
98 //
99 // For arrays, layout helper is a negative number, containing four
100 // distinct bytes, as follows:
101 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
102 // where:
103 // tag is 0x80 if the elements are oops, 0xC0 if non-oops, 0xA0 if value types
104 // hsz is array header size in bytes (i.e., offset of first element)
105 // ebt is the BasicType of the elements
106 // esz is the element size in bytes
107 // This packed word is arranged so as to be quickly unpacked by the
108 // various fast paths that use the various subfields.
109 //
110 // The esz bits can be used directly by a SLL instruction, without masking.
111 //
112 // Note that the array-kind tag looks like 0x00 for instance klasses,
113 // since their length in bytes is always less than 24Mb.
114 //
115 // Final note: This comes first, immediately after C++ vtable,
116 // because it is frequently queried.
117 jint _layout_helper;
118
119 // Klass identifier used to implement devirtualized oop closure dispatching.
120 const KlassID _id;
121
122 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
123 // and _primary_supers all help make fast subtype checks. See big discussion
124 // in doc/server_compiler/checktype.txt
125 //
126 // Where to look to observe a supertype (it is &_secondary_super_cache for
127 // secondary supers, else is &_primary_supers[depth()].
128 juint _super_check_offset;
129
130 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
131 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
132 Symbol* _name;
133
134 // Cache of last observed secondary supertype
135 Klass* _secondary_super_cache;
136 // Array of all secondary supertypes
137 Array<Klass*>* _secondary_supers;
138 // Ordered list of all primary supertypes
139 Klass* _primary_supers[_primary_super_limit];
140 // java/lang/Class instance mirroring this class
141 OopHandle _java_mirror;
142 // Superclass
143 Klass* _super;
144 // First subclass (NULL if none); _subklass->next_sibling() is next one
145 Klass* volatile _subklass;
146 // Sibling link (or NULL); links all subklasses of a klass
147 Klass* volatile _next_sibling;
148
149 // All klasses loaded by a class loader are chained through these links
150 Klass* _next_link;
151
152 // The VM's representation of the ClassLoader used to load this class.
153 // Provide access the corresponding instance java.lang.ClassLoader.
154 ClassLoaderData* _class_loader_data;
155
156 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
157 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
158
159 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
160
161 // Biased locking implementation and statistics
162 // (the 64-bit chunk goes first, to avoid some fragmentation)
163 jlong _last_biased_lock_bulk_revocation_time;
164 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
165 jint _biased_lock_revocation_count;
166
167 // vtable length
168 int _vtable_len;
169
170 private:
171 // This is an index into FileMapHeader::_shared_path_table[], to
172 // associate this class with the JAR file where it's loaded from during
173 // dump time. If a class is not loaded from the shared archive, this field is
174 // -1.
175 jshort _shared_class_path_index;
176
177 #if INCLUDE_CDS
178 // Flags of the current shared class.
179 u2 _shared_class_flags;
180 enum {
181 _has_raw_archived_mirror = 1
182 };
183 #endif
184 // The _archived_mirror is set at CDS dump time pointing to the cached mirror
185 // in the open archive heap region when archiving java object is supported.
186 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;)
187
188 protected:
189
190 // Constructor
191 Klass(KlassID id);
192 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
193
194 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
195
196 public:
197 int id() { return _id; }
198
199 enum DefaultsLookupMode { find_defaults, skip_defaults };
200 enum OverpassLookupMode { find_overpass, skip_overpass };
201 enum StaticLookupMode { find_static, skip_static };
202 enum PrivateLookupMode { find_private, skip_private };
203
204 bool is_klass() const volatile { return true; }
205
206 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
207 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
208 // If this is not what your code expects, you're probably looking for Klass::java_super().
209 Klass* super() const { return _super; }
210 void set_super(Klass* k) { _super = k; }
211
212 // initializes _super link, _primary_supers & _secondary_supers arrays
213 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
214
215 // klass-specific helper for initializing _secondary_supers
216 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
217 Array<InstanceKlass*>* transitive_interfaces);
218
219 // java_super is the Java-level super type as specified by Class.getSuperClass.
220 virtual InstanceKlass* java_super() const { return NULL; }
221
222 juint super_check_offset() const { return _super_check_offset; }
223 void set_super_check_offset(juint o) { _super_check_offset = o; }
224
225 Klass* secondary_super_cache() const { return _secondary_super_cache; }
226 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
227
228 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
229 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
230
231 // Return the element of the _super chain of the given depth.
232 // If there is no such element, return either NULL or this.
233 Klass* primary_super_of_depth(juint i) const {
234 assert(i < primary_super_limit(), "oob");
235 Klass* super = _primary_supers[i];
236 assert(super == NULL || super->super_depth() == i, "correct display");
237 return super;
238 }
239
240 // Can this klass be a primary super? False for interfaces and arrays of
241 // interfaces. False also for arrays or classes with long super chains.
242 bool can_be_primary_super() const {
243 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
244 return super_check_offset() != secondary_offset;
245 }
246 virtual bool can_be_primary_super_slow() const;
247
248 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
249 juint super_depth() const {
250 if (!can_be_primary_super()) {
251 return primary_super_limit();
252 } else {
253 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
254 assert(d < primary_super_limit(), "oob");
255 assert(_primary_supers[d] == this, "proper init");
256 return d;
257 }
258 }
259
260 // java mirror
261 oop java_mirror() const;
262 oop java_mirror_no_keepalive() const;
263 void set_java_mirror(Handle m);
264
265 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier
266 narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(0); // no GC barrier
267 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier
268
269 // Temporary mirror switch used by RedefineClasses
270 // Both mirrors are on the ClassLoaderData::_handles list already so no
271 // barriers are needed.
272 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; }
273 OopHandle java_mirror_handle() const {
274 return _java_mirror;
275 }
276
277 // modifier flags
278 jint modifier_flags() const { return _modifier_flags; }
279 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
280
281 // size helper
282 int layout_helper() const { return _layout_helper; }
283 void set_layout_helper(int lh) { _layout_helper = lh; }
284
285 // Note: for instances layout_helper() may include padding.
286 // Use InstanceKlass::contains_field_offset to classify field offsets.
287
288 // sub/superklass links
289 Klass* subklass(bool log = false) const;
290 Klass* next_sibling(bool log = false) const;
291
292 InstanceKlass* superklass() const;
293 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
294
295 void set_next_link(Klass* k) { _next_link = k; }
296 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
297
298 // class loader data
299 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
300 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
301
302 int shared_classpath_index() const {
303 return _shared_class_path_index;
304 };
305
306 void set_shared_classpath_index(int index) {
307 _shared_class_path_index = index;
308 };
309
310 void set_has_raw_archived_mirror() {
311 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;)
312 }
313 void clear_has_raw_archived_mirror() {
314 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;)
315 }
316 bool has_raw_archived_mirror() const {
317 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;)
318 NOT_CDS(return false;)
319 }
320
321 // Obtain the module or package for this class
322 virtual ModuleEntry* module() const = 0;
323 virtual PackageEntry* package() const = 0;
324
325 protected: // internal accessors
326 void set_subklass(Klass* s);
327 void set_next_sibling(Klass* s);
328
329 public:
330
331 // Compiler support
332 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
333 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
334 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
335 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
336 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
337 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
338 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
339 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
340 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
341
342 // Unpacking layout_helper:
343 enum {
344 _lh_neutral_value = 0, // neutral non-array non-instance value
345 _lh_instance_slow_path_bit = 0x01,
346 _lh_log2_element_size_shift = BitsPerByte*0,
347 _lh_log2_element_size_mask = BitsPerLong-1,
348 _lh_element_type_shift = BitsPerByte*1,
349 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
350 _lh_header_size_shift = BitsPerByte*2,
351 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
352 _lh_array_tag_bits = 3,
353 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits
354 };
355
356 static const unsigned int _lh_array_tag_type_value = 0Xfffffffc;
357 static const unsigned int _lh_array_tag_vt_value = 0Xfffffffd;
358 static const unsigned int _lh_array_tag_obj_value = 0Xfffffffe;
359
360 static int layout_helper_size_in_bytes(jint lh) {
361 assert(lh > (jint)_lh_neutral_value, "must be instance");
362 return (int) lh & ~_lh_instance_slow_path_bit;
363 }
364 static bool layout_helper_needs_slow_path(jint lh) {
365 assert(lh > (jint)_lh_neutral_value, "must be instance");
366 return (lh & _lh_instance_slow_path_bit) != 0;
367 }
368 static bool layout_helper_is_instance(jint lh) {
369 return (jint)lh > (jint)_lh_neutral_value;
370 }
371 static bool layout_helper_is_array(jint lh) {
372 return (jint)lh < (jint)_lh_neutral_value;
373 }
374 static bool layout_helper_is_typeArray(jint lh) {
375 return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift);
376 }
377 static bool layout_helper_is_objArray(jint lh) {
378 return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift);
379 }
380 static bool layout_helper_is_valueArray(jint lh) {
381 return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift);
382 }
383 static int layout_helper_header_size(jint lh) {
384 assert(lh < (jint)_lh_neutral_value, "must be array");
385 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
386 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
387 return hsize;
388 }
389 static BasicType layout_helper_element_type(jint lh) {
390 assert(lh < (jint)_lh_neutral_value, "must be array");
391 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
392 assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_VALUETYPE, "sanity");
393 return (BasicType) btvalue;
394 }
395
396 // Want a pattern to quickly diff against layout header in register
397 // find something less clever!
398 static int layout_helper_boolean_diffbit() {
399 jint zlh = array_layout_helper(T_BOOLEAN);
400 jint blh = array_layout_helper(T_BYTE);
401 assert(zlh != blh, "array layout helpers must differ");
402 int diffbit = 1;
403 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
404 diffbit <<= 1;
405 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
406 }
407 return diffbit;
408 }
409
410 static int layout_helper_log2_element_size(jint lh) {
411 assert(lh < (jint)_lh_neutral_value, "must be array");
412 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
413 assert(layout_helper_element_type(lh) == T_VALUETYPE || l2esz <= LogBytesPerLong,
414 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
415 return l2esz;
416 }
417 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
418 return (tag << _lh_array_tag_shift)
419 | (hsize << _lh_header_size_shift)
420 | ((int)etype << _lh_element_type_shift)
421 | (log2_esize << _lh_log2_element_size_shift);
422 }
423 static jint instance_layout_helper(jint size, bool slow_path_flag) {
424 return (size << LogBytesPerWord)
425 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
426 }
427 static int layout_helper_to_size_helper(jint lh) {
428 assert(lh > (jint)_lh_neutral_value, "must be instance");
429 // Note that the following expression discards _lh_instance_slow_path_bit.
430 return lh >> LogBytesPerWord;
431 }
432 // Out-of-line version computes everything based on the etype:
433 static jint array_layout_helper(BasicType etype);
434
435 // What is the maximum number of primary superclasses any klass can have?
436 static juint primary_super_limit() { return _primary_super_limit; }
437
438 // vtables
439 klassVtable vtable() const;
440 int vtable_length() const { return _vtable_len; }
441
442 // subclass check
443 bool is_subclass_of(const Klass* k) const;
444 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
445 bool is_subtype_of(Klass* k) const {
446 juint off = k->super_check_offset();
447 Klass* sup = *(Klass**)( (address)this + off );
448 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
449 if (sup == k) {
450 return true;
451 } else if (off != secondary_offset) {
452 return false;
453 } else {
454 return search_secondary_supers(k);
455 }
456 }
457
458 bool search_secondary_supers(Klass* k) const;
459
460 // Find LCA in class hierarchy
461 Klass *LCA( Klass *k );
462
463 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
464 // if not, throw either an Error or an Exception.
465 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
466
467 // array copying
468 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
469
470 // tells if the class should be initialized
471 virtual bool should_be_initialized() const { return false; }
472 // initializes the klass
473 virtual void initialize(TRAPS);
474 // lookup operation for MethodLookupCache
475 friend class MethodLookupCache;
476 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
477 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature,
478 OverpassLookupMode overpass_mode,
479 PrivateLookupMode = find_private) const;
480 public:
481 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
482 return uncached_lookup_method(name, signature, find_overpass);
483 }
484
485 // array class with specific rank
486 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
487
488 // array class with this klass as element type
489 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
490
491 // These will return NULL instead of allocating on the heap:
492 // NB: these can block for a mutex, like other functions with TRAPS arg.
493 Klass* array_klass_or_null(int rank);
494 Klass* array_klass_or_null();
495
496 virtual oop protection_domain() const = 0;
497
498 oop class_loader() const;
499
500 // This loads the klass's holder as a phantom. This is useful when a weak Klass
501 // pointer has been "peeked" and then must be kept alive before it may
502 // be used safely. All uses of klass_holder need to apply the appropriate barriers,
503 // except during GC.
504 oop klass_holder() const { return class_loader_data()->holder_phantom(); }
505
506 protected:
507 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
508 virtual Klass* array_klass_impl(bool or_null, TRAPS);
509
510 // Error handling when length > max_length or length < 0
511 static void check_array_allocation_length(int length, int max_length, TRAPS);
512
513 void set_vtable_length(int len) { _vtable_len= len; }
514
515 vtableEntry* start_of_vtable() const;
516 public:
517 Method* method_at_vtable(int index);
518
519 static ByteSize vtable_start_offset();
520 static ByteSize vtable_length_offset() {
521 return byte_offset_of(Klass, _vtable_len);
522 }
523
524 // CDS support - remove and restore oops from metadata. Oops are not shared.
525 virtual void remove_unshareable_info();
526 virtual void remove_java_mirror();
527 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
528
529 public:
530 // subclass accessor (here for convenience; undefined for non-klass objects)
531 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
532 public:
533 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
534 // These functions describe behavior for the oop not the KLASS.
535
536 // actual oop size of obj in memory
537 virtual int oop_size(oop obj) const = 0;
538
539 // Size of klass in word size.
540 virtual int size() const = 0;
541 #if INCLUDE_SERVICES
542 virtual void collect_statistics(KlassSizeStats *sz) const;
543 #endif
544
545 // Returns the Java name for a class (Resource allocated)
546 // For arrays, this returns the name of the element with a leading '['.
547 // For classes, this returns the name with the package separators
548 // turned into '.'s.
549 const char* external_name() const;
550 // Returns the name for a class (Resource allocated) as the class
551 // would appear in a signature.
552 // For arrays, this returns the name of the element with a leading '['.
553 // For classes, this returns the name with a leading 'L' and a trailing ';'
554 // and the package separators as '/'.
555 // For value classes, this returns the name with a leading 'Q' and a trailing ';'
556 // and the package separators as '/'.
557 virtual const char* signature_name() const;
558
559 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
560 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
561
562 // Returns "interface", "abstract class" or "class".
563 const char* external_kind() const;
564
565 // type testing operations
566 #ifdef ASSERT
567 protected:
568 virtual bool is_instance_klass_slow() const { return false; }
569 virtual bool is_array_klass_slow() const { return false; }
570 virtual bool is_objArray_klass_slow() const { return false; }
571 virtual bool is_typeArray_klass_slow() const { return false; }
572 virtual bool is_valueArray_klass_slow() const { return false; }
573 #endif // ASSERT
574 // current implementation uses this method even in non debug builds
575 virtual bool is_value_slow() const { return false; }
576 public:
577
578 // Fast non-virtual versions
579 #ifndef ASSERT
580 #define assert_same_query(xval, xcheck) xval
581 #else
582 private:
583 static bool assert_same_query(bool xval, bool xslow) {
584 assert(xval == xslow, "slow and fast queries agree");
585 return xval;
586 }
587 public:
588 #endif
589 inline bool is_instance_klass() const { return assert_same_query(
590 layout_helper_is_instance(layout_helper()),
591 is_instance_klass_slow()); }
592 inline bool is_array_klass() const { return assert_same_query(
593 layout_helper_is_array(layout_helper()),
594 is_array_klass_slow()); }
595 inline bool is_objArray_klass() const { return assert_same_query(
596 layout_helper_is_objArray(layout_helper()),
597 is_objArray_klass_slow()); }
598 inline bool is_typeArray_klass() const { return assert_same_query(
599 layout_helper_is_typeArray(layout_helper()),
600 is_typeArray_klass_slow()); }
601 inline bool is_value() const { return is_value_slow(); } //temporary hack
602 inline bool is_valueArray_klass() const { return assert_same_query(
603 layout_helper_is_valueArray(layout_helper()),
604 is_valueArray_klass_slow()); }
605
606 #undef assert_same_query
607
608 // Access flags
609 AccessFlags access_flags() const { return _access_flags; }
610 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
611
612 bool is_public() const { return _access_flags.is_public(); }
613 bool is_final() const { return _access_flags.is_final(); }
614 bool is_interface() const { return _access_flags.is_interface(); }
615 bool is_abstract() const { return _access_flags.is_abstract(); }
616 bool is_super() const { return _access_flags.is_super(); }
617 bool is_synthetic() const { return _access_flags.is_synthetic(); }
618 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
619 bool has_finalizer() const { return _access_flags.has_finalizer(); }
620 bool has_final_method() const { return _access_flags.has_final_method(); }
621 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
622 void set_has_final_method() { _access_flags.set_has_final_method(); }
623 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
624 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
625 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
626 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
627 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
628 void set_is_shared() { _access_flags.set_is_shared_class(); }
629
630 bool is_cloneable() const;
631 void set_is_cloneable();
632
633 // Biased locking support
634 // Note: the prototype header is always set up to be at least the
635 // prototype markOop. If biased locking is enabled it may further be
636 // biasable and have an epoch.
637 markOop prototype_header() const { return _prototype_header; }
638 static inline markOop default_prototype_header(Klass* k) {
639 return (k == NULL) ? markOopDesc::prototype() : k->prototype_header();
640 }
641
642 // NOTE: once instances of this klass are floating around in the
643 // system, this header must only be updated at a safepoint.
644 // NOTE 2: currently we only ever set the prototype header to the
645 // biasable prototype for instanceKlasses. There is no technical
646 // reason why it could not be done for arrayKlasses aside from
647 // wanting to reduce the initial scope of this optimization. There
648 // are potential problems in setting the bias pattern for
649 // JVM-internal oops.
650 inline void set_prototype_header(markOop header);
651 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
652
653 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
654 // Atomically increments biased_lock_revocation_count and returns updated value
655 int atomic_incr_biased_lock_revocation_count();
656 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
657 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
658 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
659
660 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
661
662 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
663 virtual MetaspaceObj::Type type() const { return ClassType; }
664
665 // Iff the class loader (or mirror for unsafe anonymous classes) is alive the
666 // Klass is considered alive. This is safe to call before the CLD is marked as
667 // unloading, and hence during concurrent class unloading.
668 bool is_loader_alive() const { return class_loader_data()->is_alive(); }
669
670 void clean_subklass();
671
672 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
673 static void clean_subklass_tree() {
674 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
675 }
676
677 virtual void array_klasses_do(void f(Klass* k)) {}
678
679 // Return self, except for abstract classes with exactly 1
680 // implementor. Then return the 1 concrete implementation.
681 Klass *up_cast_abstract();
682
683 // klass name
684 Symbol* name() const { return _name; }
685 void set_name(Symbol* n);
686
687 public:
688 // jvm support
689 virtual jint compute_modifier_flags(TRAPS) const;
690
691 // JVMTI support
692 virtual jint jvmti_class_status() const;
693
694 // Printing
695 virtual void print_on(outputStream* st) const;
696
697 virtual void oop_print_value_on(oop obj, outputStream* st);
698 virtual void oop_print_on (oop obj, outputStream* st);
699
700 virtual const char* internal_name() const = 0;
701
702 // Verification
703 virtual void verify_on(outputStream* st);
704 void verify() { verify_on(tty); }
705
706 #ifndef PRODUCT
707 bool verify_vtable_index(int index);
708 #endif
709
710 virtual void oop_verify_on(oop obj, outputStream* st);
711
712 // for error reporting
713 static Klass* decode_klass_raw(narrowKlass narrow_klass);
714 static bool is_valid(Klass* k);
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_OOPS_KLASS_HPP