1 /*
2 * Copyright (c) 1997, 2022, 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
21 * questions.
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23 */
24
25 #ifndef SHARE_OOPS_KLASS_HPP
26 #define SHARE_OOPS_KLASS_HPP
27
28 #include "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/markWord.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 Kinds for all subclasses of Klass
41 enum KlassKind {
42 InstanceKlassKind,
43 InstanceRefKlassKind,
44 InstanceMirrorKlassKind,
45 InstanceClassLoaderKlassKind,
46 InstanceStackChunkKlassKind,
47 TypeArrayKlassKind,
48 ObjArrayKlassKind
49 };
50
51 const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
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 ClassLoaderData;
71 class fieldDescriptor;
72 class klassVtable;
73 class ModuleEntry;
74 class PackageEntry;
75 class ParCompactionManager;
76 class PSPromotionManager;
77 class vtableEntry;
78
79 class Klass : public Metadata {
80 friend class VMStructs;
81 friend class JVMCIVMStructs;
82 protected:
83 // If you add a new field that points to any metaspace object, you
84 // must add this field to Klass::metaspace_pointers_do().
85
86 // note: put frequently-used fields together at start of klass structure
87 // for better cache behavior (may not make much of a difference but sure won't hurt)
88 enum { _primary_super_limit = 8 };
89
90 // The "layout helper" is a combined descriptor of object layout.
91 // For klasses which are neither instance nor array, the value is zero.
92 //
93 // For instances, layout helper is a positive number, the instance size.
94 // This size is already passed through align_object_size and scaled to bytes.
95 // The low order bit is set if instances of this class cannot be
96 // allocated using the fastpath.
97 //
98 // For arrays, layout helper is a negative number, containing four
99 // distinct bytes, as follows:
100 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
101 // where:
102 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
103 // hsz is array header size in bytes (i.e., offset of first element)
104 // ebt is the BasicType of the elements
105 // esz is the element size in bytes
106 // This packed word is arranged so as to be quickly unpacked by the
107 // various fast paths that use the various subfields.
108 //
109 // The esz bits can be used directly by a SLL instruction, without masking.
110 //
111 // Note that the array-kind tag looks like 0x00 for instance klasses,
112 // since their length in bytes is always less than 24Mb.
113 //
114 // Final note: This comes first, immediately after C++ vtable,
115 // because it is frequently queried.
116 jint _layout_helper;
117
118 // Klass kind used to resolve the runtime type of the instance.
119 // - Used to implement devirtualized oop closure dispatching.
120 // - Various type checking in the JVM
121 const KlassKind _kind;
122
123 // Processed access flags, for use by Class.getModifiers.
124 jint _modifier_flags;
125
126 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
127 // and _primary_supers all help make fast subtype checks. See big discussion
128 // in doc/server_compiler/checktype.txt
129 //
130 // Where to look to observe a supertype (it is &_secondary_super_cache for
131 // secondary supers, else is &_primary_supers[depth()].
132 juint _super_check_offset;
133
134 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
135 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
136 Symbol* _name;
137
138 // Cache of last observed secondary supertype
139 Klass* _secondary_super_cache;
140 // Array of all secondary supertypes
141 Array<Klass*>* _secondary_supers;
142 // Ordered list of all primary supertypes
143 Klass* _primary_supers[_primary_super_limit];
144 // java/lang/Class instance mirroring this class
145 OopHandle _java_mirror;
146 // Superclass
147 Klass* _super;
148 // First subclass (NULL if none); _subklass->next_sibling() is next one
149 Klass* volatile _subklass;
150 // Sibling link (or NULL); links all subklasses of a klass
151 Klass* volatile _next_sibling;
152
153 // All klasses loaded by a class loader are chained through these links
154 Klass* _next_link;
155
156 // The VM's representation of the ClassLoader used to load this class.
157 // Provide access the corresponding instance java.lang.ClassLoader.
158 ClassLoaderData* _class_loader_data;
159
160 int _vtable_len; // vtable length. This field may be read very often when we
161 // have lots of itable dispatches (e.g., lambdas and streams).
162 // Keep it away from the beginning of a Klass to avoid cacheline
163 // contention that may happen when a nearby object is modified.
164 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
165
166 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
167
168 markWord _prototype_header; // Used to initialize objects' header
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 // Various attributes for shared classes. Should be zero for a non-shared class.
179 u2 _shared_class_flags;
180 enum CDSSharedClassFlags {
181 _archived_lambda_proxy_is_available = 1 << 1,
182 _has_value_based_class_annotation = 1 << 2,
183 _verified_at_dump_time = 1 << 3,
184 _has_archived_enum_objs = 1 << 4,
185 // This class was not loaded from a classfile in the module image
186 // or classpath.
187 _is_generated_shared_class = 1 << 5
188 };
189 #endif
190
191 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
192
193 protected:
194
195 // Constructor
196 Klass(KlassKind kind);
197 Klass() : _kind(KlassKind(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
198
199 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
200
201 public:
202 int kind() { return _kind; }
203
204 enum class DefaultsLookupMode { find, skip };
205 enum class OverpassLookupMode { find, skip };
206 enum class StaticLookupMode { find, skip };
207 enum class PrivateLookupMode { find, skip };
208
209 virtual bool is_klass() const { return true; }
210
211 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
212 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
213 // If this is not what your code expects, you're probably looking for Klass::java_super().
214 Klass* super() const { return _super; }
215 void set_super(Klass* k) { _super = k; }
216
217 // initializes _super link, _primary_supers & _secondary_supers arrays
218 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
219
220 // klass-specific helper for initializing _secondary_supers
221 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
222 Array<InstanceKlass*>* transitive_interfaces);
223
224 // java_super is the Java-level super type as specified by Class.getSuperClass.
225 virtual InstanceKlass* java_super() const { return NULL; }
226
227 juint super_check_offset() const { return _super_check_offset; }
228 void set_super_check_offset(juint o) { _super_check_offset = o; }
229
230 Klass* secondary_super_cache() const { return _secondary_super_cache; }
231 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
232
233 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
234 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
235
236 // Return the element of the _super chain of the given depth.
237 // If there is no such element, return either NULL or this.
238 Klass* primary_super_of_depth(juint i) const {
239 assert(i < primary_super_limit(), "oob");
240 Klass* super = _primary_supers[i];
241 assert(super == NULL || super->super_depth() == i, "correct display");
242 return super;
243 }
244
245 // Can this klass be a primary super? False for interfaces and arrays of
246 // interfaces. False also for arrays or classes with long super chains.
247 bool can_be_primary_super() const {
248 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
249 return super_check_offset() != secondary_offset;
250 }
251 virtual bool can_be_primary_super_slow() const;
252
253 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
254 juint super_depth() const {
255 if (!can_be_primary_super()) {
256 return primary_super_limit();
257 } else {
258 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
259 assert(d < primary_super_limit(), "oob");
260 assert(_primary_supers[d] == this, "proper init");
261 return d;
262 }
263 }
264
265 // java mirror
266 oop java_mirror() const;
267 oop java_mirror_no_keepalive() const;
268 void set_java_mirror(Handle m);
269
270 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(NULL);
271 void set_archived_java_mirror(oop m) NOT_CDS_JAVA_HEAP_RETURN;
272
273 // Temporary mirror switch used by RedefineClasses
274 void replace_java_mirror(oop mirror);
275
276 // Set java mirror OopHandle to NULL for CDS
277 // This leaves the OopHandle in the CLD, but that's ok, you can't release them.
278 void clear_java_mirror_handle() { _java_mirror = OopHandle(); }
279
280 // modifier flags
281 jint modifier_flags() const { return _modifier_flags; }
282 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
283
284 // size helper
285 int layout_helper() const { return _layout_helper; }
286 void set_layout_helper(int lh) { _layout_helper = lh; }
287
288 // Note: for instances layout_helper() may include padding.
289 // Use InstanceKlass::contains_field_offset to classify field offsets.
290
291 // sub/superklass links
292 Klass* subklass(bool log = false) const;
293 Klass* next_sibling(bool log = false) const;
294
295 InstanceKlass* superklass() const;
296 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
297
298 void set_next_link(Klass* k) { _next_link = k; }
299 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
300 Klass** next_link_addr() { return &_next_link; }
301
302 // class loader data
303 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
304 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
305
306 int shared_classpath_index() const {
307 return _shared_class_path_index;
308 };
309
310 void set_shared_classpath_index(int index) {
311 _shared_class_path_index = index;
312 };
313
314 bool has_archived_mirror_index() const {
315 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;)
316 NOT_CDS_JAVA_HEAP(return false);
317 }
318
319 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN;
320
321 void set_lambda_proxy_is_available() {
322 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;)
323 }
324 void clear_lambda_proxy_is_available() {
325 CDS_ONLY(_shared_class_flags &= ~_archived_lambda_proxy_is_available;)
326 }
327 bool lambda_proxy_is_available() const {
328 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;)
329 NOT_CDS(return false;)
330 }
331
332 void set_has_value_based_class_annotation() {
333 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;)
334 }
335 void clear_has_value_based_class_annotation() {
336 CDS_ONLY(_shared_class_flags &= ~_has_value_based_class_annotation;)
337 }
338 bool has_value_based_class_annotation() const {
339 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;)
340 NOT_CDS(return false;)
341 }
342
343 void set_verified_at_dump_time() {
344 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;)
345 }
346 bool verified_at_dump_time() const {
347 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;)
348 NOT_CDS(return false;)
349 }
350
351 void set_has_archived_enum_objs() {
352 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;)
353 }
354 bool has_archived_enum_objs() const {
355 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;)
356 NOT_CDS(return false;)
357 }
358
359 void set_is_generated_shared_class() {
360 CDS_ONLY(_shared_class_flags |= _is_generated_shared_class;)
361 }
362 bool is_generated_shared_class() const {
363 CDS_ONLY(return (_shared_class_flags & _is_generated_shared_class) != 0;)
364 NOT_CDS(return false;)
365 }
366
367 // Obtain the module or package for this class
368 virtual ModuleEntry* module() const = 0;
369 virtual PackageEntry* package() const = 0;
370
371 protected: // internal accessors
372 void set_subklass(Klass* s);
373 void set_next_sibling(Klass* s);
374
375 public:
376
377 // Compiler support
378 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
379 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
380 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
381 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
382 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
383 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
384 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
385 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
386 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
387 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
388
389 // Unpacking layout_helper:
390 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
391 static const int _lh_instance_slow_path_bit = 0x01;
392 static const int _lh_log2_element_size_shift = BitsPerByte*0;
393 static const int _lh_log2_element_size_mask = BitsPerLong-1;
394 static const int _lh_element_type_shift = BitsPerByte*1;
395 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
396 static const int _lh_header_size_shift = BitsPerByte*2;
397 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
398 static const int _lh_array_tag_bits = 2;
399 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
400 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30
401
402 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
403
404 static int layout_helper_size_in_bytes(jint lh) {
405 assert(lh > (jint)_lh_neutral_value, "must be instance");
406 return (int) lh & ~_lh_instance_slow_path_bit;
407 }
408 static bool layout_helper_needs_slow_path(jint lh) {
409 assert(lh > (jint)_lh_neutral_value, "must be instance");
410 return (lh & _lh_instance_slow_path_bit) != 0;
411 }
412 static bool layout_helper_is_instance(jint lh) {
413 return (jint)lh > (jint)_lh_neutral_value;
414 }
415 static bool layout_helper_is_array(jint lh) {
416 return (jint)lh < (jint)_lh_neutral_value;
417 }
418 static bool layout_helper_is_typeArray(jint lh) {
419 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
420 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
421 }
422 static bool layout_helper_is_objArray(jint lh) {
423 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
424 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
425 }
426 static int layout_helper_header_size(jint lh) {
427 assert(lh < (jint)_lh_neutral_value, "must be array");
428 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
429 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
430 return hsize;
431 }
432 static BasicType layout_helper_element_type(jint lh) {
433 assert(lh < (jint)_lh_neutral_value, "must be array");
434 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
435 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
436 return (BasicType) btvalue;
437 }
438
439 // Want a pattern to quickly diff against layout header in register
440 // find something less clever!
441 static int layout_helper_boolean_diffbit() {
442 jint zlh = array_layout_helper(T_BOOLEAN);
443 jint blh = array_layout_helper(T_BYTE);
444 assert(zlh != blh, "array layout helpers must differ");
445 int diffbit = 1;
446 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
447 diffbit <<= 1;
448 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
449 }
450 return diffbit;
451 }
452
453 static int layout_helper_log2_element_size(jint lh) {
454 assert(lh < (jint)_lh_neutral_value, "must be array");
455 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
456 assert(l2esz <= LogBytesPerLong,
457 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
458 return l2esz;
459 }
460 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
461 return (tag << _lh_array_tag_shift)
462 | (hsize << _lh_header_size_shift)
463 | ((int)etype << _lh_element_type_shift)
464 | (log2_esize << _lh_log2_element_size_shift);
465 }
466 static jint instance_layout_helper(jint size, bool slow_path_flag) {
467 return (size << LogBytesPerWord)
468 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
469 }
470 static int layout_helper_to_size_helper(jint lh) {
471 assert(lh > (jint)_lh_neutral_value, "must be instance");
472 // Note that the following expression discards _lh_instance_slow_path_bit.
473 return lh >> LogBytesPerWord;
474 }
475 // Out-of-line version computes everything based on the etype:
476 static jint array_layout_helper(BasicType etype);
477
478 // What is the maximum number of primary superclasses any klass can have?
479 static juint primary_super_limit() { return _primary_super_limit; }
480
481 // vtables
482 klassVtable vtable() const;
483 int vtable_length() const { return _vtable_len; }
484
485 // subclass check
486 bool is_subclass_of(const Klass* k) const;
487 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
488 bool is_subtype_of(Klass* k) const {
489 juint off = k->super_check_offset();
490 Klass* sup = *(Klass**)( (address)this + off );
491 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
492 if (sup == k) {
493 return true;
494 } else if (off != secondary_offset) {
495 return false;
496 } else {
497 return search_secondary_supers(k);
498 }
499 }
500
501 bool search_secondary_supers(Klass* k) const;
502
503 // Find LCA in class hierarchy
504 Klass *LCA( Klass *k );
505
506 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
507 // if not, throw either an Error or an Exception.
508 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
509
510 // array copying
511 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
512
513 // tells if the class should be initialized
514 virtual bool should_be_initialized() const { return false; }
515 // initializes the klass
516 virtual void initialize(TRAPS);
517 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
518 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature,
519 OverpassLookupMode overpass_mode,
520 PrivateLookupMode = PrivateLookupMode::find) const;
521 public:
522 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
523 return uncached_lookup_method(name, signature, OverpassLookupMode::find);
524 }
525
526 // array class with specific rank
527 virtual Klass* array_klass(int rank, TRAPS) = 0;
528
529 // array class with this klass as element type
530 virtual Klass* array_klass(TRAPS) = 0;
531
532 // These will return NULL instead of allocating on the heap:
533 virtual Klass* array_klass_or_null(int rank) = 0;
534 virtual Klass* array_klass_or_null() = 0;
535
536 virtual oop protection_domain() const = 0;
537
538 oop class_loader() const;
539
540 inline oop klass_holder() const;
541
542 protected:
543
544 // Error handling when length > max_length or length < 0
545 static void check_array_allocation_length(int length, int max_length, TRAPS);
546
547 void set_vtable_length(int len) { _vtable_len= len; }
548
549 vtableEntry* start_of_vtable() const;
550 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
551 public:
552 Method* method_at_vtable(int index);
553
554 static ByteSize vtable_start_offset();
555 static ByteSize vtable_length_offset() {
556 return byte_offset_of(Klass, _vtable_len);
557 }
558
559 // CDS support - remove and restore oops from metadata. Oops are not shared.
560 virtual void remove_unshareable_info();
561 virtual void remove_java_mirror();
562
563 bool is_unshareable_info_restored() const {
564 assert(is_shared(), "use this for shared classes only");
565 if (has_archived_mirror_index()) {
566 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap
567 return false;
568 } else if (_java_mirror.ptr_raw() == NULL) {
569 return false;
570 } else {
571 return true;
572 }
573 }
574
575 public:
576 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
577 // These functions describe behavior for the oop not the KLASS.
578
579 // actual oop size of obj in memory in word size.
580 virtual size_t oop_size(oop obj) const = 0;
581
582 // Size of klass in word size.
583 virtual int size() const = 0;
584
585 // Returns the Java name for a class (Resource allocated)
586 // For arrays, this returns the name of the element with a leading '['.
587 // For classes, this returns the name with the package separators
588 // turned into '.'s.
589 const char* external_name() const;
590 // Returns the name for a class (Resource allocated) as the class
591 // would appear in a signature.
592 // For arrays, this returns the name of the element with a leading '['.
593 // For classes, this returns the name with a leading 'L' and a trailing ';'
594 // and the package separators as '/'.
595 virtual const char* signature_name() const;
596
597 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
598 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
599
600 // Returns "interface", "abstract class" or "class".
601 const char* external_kind() const;
602
603 // type testing operations
604 #ifdef ASSERT
605 protected:
606 virtual bool is_instance_klass_slow() const { return false; }
607 virtual bool is_array_klass_slow() const { return false; }
608 virtual bool is_objArray_klass_slow() const { return false; }
609 virtual bool is_typeArray_klass_slow() const { return false; }
610 #endif // ASSERT
611 public:
612
613 // Fast non-virtual versions
614 #ifndef ASSERT
615 #define assert_same_query(xval, xcheck) xval
616 #else
617 private:
618 static bool assert_same_query(bool xval, bool xslow) {
619 assert(xval == xslow, "slow and fast queries agree");
620 return xval;
621 }
622 public:
623 #endif
624
625 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); }
626 // Other is anything that is not one of the more specialized kinds of InstanceKlass.
627 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; }
628 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
629 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
630 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
631 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
632 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; }
633 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
634 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
635 #undef assert_same_query
636
637 // Access flags
638 AccessFlags access_flags() const { return _access_flags; }
639 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
640
641 bool is_public() const { return _access_flags.is_public(); }
642 bool is_final() const { return _access_flags.is_final(); }
643 bool is_interface() const { return _access_flags.is_interface(); }
644 bool is_abstract() const { return _access_flags.is_abstract(); }
645 bool is_super() const { return _access_flags.is_super(); }
646 bool is_synthetic() const { return _access_flags.is_synthetic(); }
647 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
648 bool has_finalizer() const { return _access_flags.has_finalizer(); }
649 bool has_final_method() const { return _access_flags.has_final_method(); }
650 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
651 void set_has_final_method() { _access_flags.set_has_final_method(); }
652 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
653 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
654 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
655 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
656 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
657 void set_is_shared() { _access_flags.set_is_shared_class(); }
658 bool is_hidden() const { return access_flags().is_hidden_class(); }
659 void set_is_hidden() { _access_flags.set_is_hidden_class(); }
660 bool is_value_based() { return _access_flags.is_value_based_class(); }
661 void set_is_value_based() { _access_flags.set_is_value_based_class(); }
662
663 inline bool is_non_strong_hidden() const;
664
665 bool is_cloneable() const;
666 void set_is_cloneable();
667
668 markWord prototype_header() const { return _prototype_header; }
669 inline void set_prototype_header(markWord header);
670 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
671
672 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
673
674 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
675 virtual MetaspaceObj::Type type() const { return ClassType; }
676
677 inline bool is_loader_alive() const;
678
679 void clean_subklass();
680
681 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
682 static void clean_subklass_tree() {
683 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
684 }
685
686 // Return self, except for abstract classes with exactly 1
687 // implementor. Then return the 1 concrete implementation.
688 Klass *up_cast_abstract();
689
690 // klass name
691 Symbol* name() const { return _name; }
692 void set_name(Symbol* n);
693
694 virtual void release_C_heap_structures(bool release_constant_pool = true);
695
696 public:
697 virtual jint compute_modifier_flags() const = 0;
698
699 // JVMTI support
700 virtual jint jvmti_class_status() const;
701
702 // Printing
703 virtual void print_on(outputStream* st) const;
704
705 virtual void oop_print_value_on(oop obj, outputStream* st);
706 virtual void oop_print_on (oop obj, outputStream* st);
707
708 virtual const char* internal_name() const = 0;
709
710 // Verification
711 virtual void verify_on(outputStream* st);
712 void verify() { verify_on(tty); }
713
714 #ifndef PRODUCT
715 bool verify_vtable_index(int index);
716 #endif
717
718 virtual void oop_verify_on(oop obj, outputStream* st);
719
720 // for error reporting
721 static bool is_valid(Klass* k);
722 };
723
724 #endif // SHARE_OOPS_KLASS_HPP