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 TypeArrayKlassKind,
47 ObjArrayKlassKind
48 };
49
50 const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
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 ClassLoaderData;
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 kind used to resolve the runtime type of the instance.
118 // - Used to implement devirtualized oop closure dispatching.
119 // - Various type checking in the JVM
120 const KlassKind _kind;
121
122 // Processed access flags, for use by Class.getModifiers.
123 jint _modifier_flags;
124
125 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
126 // and _primary_supers all help make fast subtype checks. See big discussion
127 // in doc/server_compiler/checktype.txt
128 //
129 // Where to look to observe a supertype (it is &_secondary_super_cache for
130 // secondary supers, else is &_primary_supers[depth()].
131 juint _super_check_offset;
132
133 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
134 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
135 Symbol* _name;
136
137 // Cache of last observed secondary supertype
138 Klass* _secondary_super_cache;
139 // Array of all secondary supertypes
140 Array<Klass*>* _secondary_supers;
141 // Ordered list of all primary supertypes
142 Klass* _primary_supers[_primary_super_limit];
143 // java/lang/Class instance mirroring this class
144 OopHandle _java_mirror;
145 // Superclass
146 Klass* _super;
147 // First subclass (NULL if none); _subklass->next_sibling() is next one
148 Klass* volatile _subklass;
149 // Sibling link (or NULL); links all subklasses of a klass
150 Klass* volatile _next_sibling;
151
152 // All klasses loaded by a class loader are chained through these links
153 Klass* _next_link;
154
155 // The VM's representation of the ClassLoader used to load this class.
156 // Provide access the corresponding instance java.lang.ClassLoader.
157 ClassLoaderData* _class_loader_data;
158
159 int _vtable_len; // vtable length. This field may be read very often when we
160 // have lots of itable dispatches (e.g., lambdas and streams).
161 // Keep it away from the beginning of a Klass to avoid cacheline
162 // contention that may happen when a nearby object is modified.
163 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
164
165 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
166
167 private:
168 // This is an index into FileMapHeader::_shared_path_table[], to
169 // associate this class with the JAR file where it's loaded from during
170 // dump time. If a class is not loaded from the shared archive, this field is
171 // -1.
172 jshort _shared_class_path_index;
173
174 #if INCLUDE_CDS
175 // Flags of the current shared class.
176 u2 _shared_class_flags;
177 enum {
178 _archived_lambda_proxy_is_available = 1 << 1,
179 _has_value_based_class_annotation = 1 << 2,
180 _verified_at_dump_time = 1 << 3,
181 _has_archived_enum_objs = 1 << 4,
182 _regenerated = 1 << 5
183 };
184 #endif
185
186 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
187
188 protected:
189
190 // Constructor
191 Klass(KlassKind kind);
192 Klass() : _kind(KlassKind(-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 kind() { return _kind; }
198
199 enum class DefaultsLookupMode { find, skip };
200 enum class OverpassLookupMode { find, skip };
201 enum class StaticLookupMode { find, skip };
202 enum class PrivateLookupMode { find, skip };
203
204 virtual bool is_klass() const { 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() NOT_CDS_JAVA_HEAP_RETURN_(NULL);
266 void set_archived_java_mirror(oop m) NOT_CDS_JAVA_HEAP_RETURN;
267
268 // Temporary mirror switch used by RedefineClasses
269 void replace_java_mirror(oop mirror);
270
271 // Set java mirror OopHandle to NULL for CDS
272 // This leaves the OopHandle in the CLD, but that's ok, you can't release them.
273 void clear_java_mirror_handle() { _java_mirror = OopHandle(); }
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 Klass** next_link_addr() { return &_next_link; }
296
297 // class loader data
298 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
299 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
300
301 int shared_classpath_index() const {
302 return _shared_class_path_index;
303 };
304
305 void set_shared_classpath_index(int index) {
306 _shared_class_path_index = index;
307 };
308
309 bool has_archived_mirror_index() const {
310 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;)
311 NOT_CDS_JAVA_HEAP(return false);
312 }
313
314 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN;
315
316 void set_lambda_proxy_is_available() {
317 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;)
318 }
319 void clear_lambda_proxy_is_available() {
320 CDS_ONLY(_shared_class_flags &= ~_archived_lambda_proxy_is_available;)
321 }
322 bool lambda_proxy_is_available() const {
323 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;)
324 NOT_CDS(return false;)
325 }
326
327 void set_has_value_based_class_annotation() {
328 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;)
329 }
330 void clear_has_value_based_class_annotation() {
331 CDS_ONLY(_shared_class_flags &= ~_has_value_based_class_annotation;)
332 }
333 bool has_value_based_class_annotation() const {
334 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;)
335 NOT_CDS(return false;)
336 }
337
338 void set_verified_at_dump_time() {
339 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;)
340 }
341 bool verified_at_dump_time() const {
342 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;)
343 NOT_CDS(return false;)
344 }
345
346 void set_has_archived_enum_objs() {
347 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;)
348 }
349 bool has_archived_enum_objs() const {
350 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;)
351 NOT_CDS(return false;)
352 }
353
354 void set_regenerated() {
355 CDS_ONLY(_shared_class_flags |= _regenerated;)
356 }
357 bool is_regenerated() const {
358 CDS_ONLY(return (_shared_class_flags & _regenerated) != 0;)
359 NOT_CDS(return false;)
360 }
361
362 // Obtain the module or package for this class
363 virtual ModuleEntry* module() const = 0;
364 virtual PackageEntry* package() const = 0;
365
366 protected: // internal accessors
367 void set_subklass(Klass* s);
368 void set_next_sibling(Klass* s);
369
370 public:
371
372 // Compiler support
373 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
374 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
375 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
376 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
377 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
378 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
379 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
380 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
381 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
382 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
383
384 // Unpacking layout_helper:
385 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
386 static const int _lh_instance_slow_path_bit = 0x01;
387 static const int _lh_log2_element_size_shift = BitsPerByte*0;
388 static const int _lh_log2_element_size_mask = BitsPerLong-1;
389 static const int _lh_element_type_shift = BitsPerByte*1;
390 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
391 static const int _lh_header_size_shift = BitsPerByte*2;
392 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
393 static const int _lh_array_tag_bits = 2;
394 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
395 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30
396
397 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
398
399 static int layout_helper_size_in_bytes(jint lh) {
400 assert(lh > (jint)_lh_neutral_value, "must be instance");
401 return (int) lh & ~_lh_instance_slow_path_bit;
402 }
403 static bool layout_helper_needs_slow_path(jint lh) {
404 assert(lh > (jint)_lh_neutral_value, "must be instance");
405 return (lh & _lh_instance_slow_path_bit) != 0;
406 }
407 static bool layout_helper_is_instance(jint lh) {
408 return (jint)lh > (jint)_lh_neutral_value;
409 }
410 static bool layout_helper_is_array(jint lh) {
411 return (jint)lh < (jint)_lh_neutral_value;
412 }
413 static bool layout_helper_is_typeArray(jint lh) {
414 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
415 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
416 }
417 static bool layout_helper_is_objArray(jint lh) {
418 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
419 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
420 }
421 static int layout_helper_header_size(jint lh) {
422 assert(lh < (jint)_lh_neutral_value, "must be array");
423 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
424 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
425 return hsize;
426 }
427 static BasicType layout_helper_element_type(jint lh) {
428 assert(lh < (jint)_lh_neutral_value, "must be array");
429 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
430 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
431 return (BasicType) btvalue;
432 }
433
434 // Want a pattern to quickly diff against layout header in register
435 // find something less clever!
436 static int layout_helper_boolean_diffbit() {
437 jint zlh = array_layout_helper(T_BOOLEAN);
438 jint blh = array_layout_helper(T_BYTE);
439 assert(zlh != blh, "array layout helpers must differ");
440 int diffbit = 1;
441 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
442 diffbit <<= 1;
443 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
444 }
445 return diffbit;
446 }
447
448 static int layout_helper_log2_element_size(jint lh) {
449 assert(lh < (jint)_lh_neutral_value, "must be array");
450 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
451 assert(l2esz <= LogBytesPerLong,
452 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
453 return l2esz;
454 }
455 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
456 return (tag << _lh_array_tag_shift)
457 | (hsize << _lh_header_size_shift)
458 | ((int)etype << _lh_element_type_shift)
459 | (log2_esize << _lh_log2_element_size_shift);
460 }
461 static jint instance_layout_helper(jint size, bool slow_path_flag) {
462 return (size << LogBytesPerWord)
463 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
464 }
465 static int layout_helper_to_size_helper(jint lh) {
466 assert(lh > (jint)_lh_neutral_value, "must be instance");
467 // Note that the following expression discards _lh_instance_slow_path_bit.
468 return lh >> LogBytesPerWord;
469 }
470 // Out-of-line version computes everything based on the etype:
471 static jint array_layout_helper(BasicType etype);
472
473 // What is the maximum number of primary superclasses any klass can have?
474 static juint primary_super_limit() { return _primary_super_limit; }
475
476 // vtables
477 klassVtable vtable() const;
478 int vtable_length() const { return _vtable_len; }
479
480 // subclass check
481 bool is_subclass_of(const Klass* k) const;
482 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
483 bool is_subtype_of(Klass* k) const {
484 juint off = k->super_check_offset();
485 Klass* sup = *(Klass**)( (address)this + off );
486 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
487 if (sup == k) {
488 return true;
489 } else if (off != secondary_offset) {
490 return false;
491 } else {
492 return search_secondary_supers(k);
493 }
494 }
495
496 bool search_secondary_supers(Klass* k) const;
497
498 // Find LCA in class hierarchy
499 Klass *LCA( Klass *k );
500
501 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
502 // if not, throw either an Error or an Exception.
503 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
504
505 // array copying
506 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
507
508 // tells if the class should be initialized
509 virtual bool should_be_initialized() const { return false; }
510 // initializes the klass
511 virtual void initialize(TRAPS);
512 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
513 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature,
514 OverpassLookupMode overpass_mode,
515 PrivateLookupMode = PrivateLookupMode::find) const;
516 public:
517 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
518 return uncached_lookup_method(name, signature, OverpassLookupMode::find);
519 }
520
521 // array class with specific rank
522 virtual Klass* array_klass(int rank, TRAPS) = 0;
523
524 // array class with this klass as element type
525 virtual Klass* array_klass(TRAPS) = 0;
526
527 // These will return NULL instead of allocating on the heap:
528 virtual Klass* array_klass_or_null(int rank) = 0;
529 virtual Klass* array_klass_or_null() = 0;
530
531 virtual oop protection_domain() const = 0;
532
533 oop class_loader() const;
534
535 inline oop klass_holder() const;
536
537 protected:
538
539 // Error handling when length > max_length or length < 0
540 static void check_array_allocation_length(int length, int max_length, TRAPS);
541
542 void set_vtable_length(int len) { _vtable_len= len; }
543
544 vtableEntry* start_of_vtable() const;
545 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
546 public:
547 Method* method_at_vtable(int index);
548
549 static ByteSize vtable_start_offset();
550 static ByteSize vtable_length_offset() {
551 return byte_offset_of(Klass, _vtable_len);
552 }
553
554 // CDS support - remove and restore oops from metadata. Oops are not shared.
555 virtual void remove_unshareable_info();
556 virtual void remove_java_mirror();
557
558 bool is_unshareable_info_restored() const {
559 assert(is_shared(), "use this for shared classes only");
560 if (has_archived_mirror_index()) {
561 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap
562 return false;
563 } else if (_java_mirror.ptr_raw() == NULL) {
564 return false;
565 } else {
566 return true;
567 }
568 }
569
570 public:
571 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
572 // These functions describe behavior for the oop not the KLASS.
573
574 // actual oop size of obj in memory in word size.
575 virtual size_t oop_size(oop obj) const = 0;
576
577 // Size of klass in word size.
578 virtual int size() const = 0;
579
580 // Returns the Java name for a class (Resource allocated)
581 // For arrays, this returns the name of the element with a leading '['.
582 // For classes, this returns the name with the package separators
583 // turned into '.'s.
584 const char* external_name() const;
585 // Returns the name for a class (Resource allocated) as the class
586 // would appear in a signature.
587 // For arrays, this returns the name of the element with a leading '['.
588 // For classes, this returns the name with a leading 'L' and a trailing ';'
589 // and the package separators as '/'.
590 virtual const char* signature_name() const;
591
592 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
593 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
594
595 // Returns "interface", "abstract class" or "class".
596 const char* external_kind() const;
597
598 // type testing operations
599 #ifdef ASSERT
600 protected:
601 virtual bool is_instance_klass_slow() const { return false; }
602 virtual bool is_array_klass_slow() const { return false; }
603 virtual bool is_objArray_klass_slow() const { return false; }
604 virtual bool is_typeArray_klass_slow() const { return false; }
605 #endif // ASSERT
606 public:
607
608 // Fast non-virtual versions
609 #ifndef ASSERT
610 #define assert_same_query(xval, xcheck) xval
611 #else
612 private:
613 static bool assert_same_query(bool xval, bool xslow) {
614 assert(xval == xslow, "slow and fast queries agree");
615 return xval;
616 }
617 public:
618 #endif
619
620 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceClassLoaderKlassKind, is_instance_klass_slow()); }
621 // Other is anything that is not one of the more specialized kinds of InstanceKlass.
622 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; }
623 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
624 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
625 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
626 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
627 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
628 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
629 #undef assert_same_query
630
631 // Access flags
632 AccessFlags access_flags() const { return _access_flags; }
633 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
634
635 bool is_public() const { return _access_flags.is_public(); }
636 bool is_final() const { return _access_flags.is_final(); }
637 bool is_interface() const { return _access_flags.is_interface(); }
638 bool is_abstract() const { return _access_flags.is_abstract(); }
639 bool is_super() const { return _access_flags.is_super(); }
640 bool is_synthetic() const { return _access_flags.is_synthetic(); }
641 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
642 bool has_finalizer() const { return _access_flags.has_finalizer(); }
643 bool has_final_method() const { return _access_flags.has_final_method(); }
644 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
645 void set_has_final_method() { _access_flags.set_has_final_method(); }
646 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
647 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
648 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
649 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
650 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
651 void set_is_shared() { _access_flags.set_is_shared_class(); }
652 bool is_hidden() const { return access_flags().is_hidden_class(); }
653 void set_is_hidden() { _access_flags.set_is_hidden_class(); }
654 bool is_value_based() { return _access_flags.is_value_based_class(); }
655 void set_is_value_based() { _access_flags.set_is_value_based_class(); }
656
657 inline bool is_non_strong_hidden() const;
658
659 bool is_cloneable() const;
660 void set_is_cloneable();
661
662 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
663
664 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
665 virtual MetaspaceObj::Type type() const { return ClassType; }
666
667 inline bool is_loader_alive() const;
668
669 void clean_subklass();
670
671 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
672 static void clean_subklass_tree() {
673 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
674 }
675
676 // Return self, except for abstract classes with exactly 1
677 // implementor. Then return the 1 concrete implementation.
678 Klass *up_cast_abstract();
679
680 // klass name
681 Symbol* name() const { return _name; }
682 void set_name(Symbol* n);
683
684 virtual void release_C_heap_structures(bool release_constant_pool = true);
685
686 public:
687 virtual jint compute_modifier_flags() const = 0;
688
689 // JVMTI support
690 virtual jint jvmti_class_status() const;
691
692 // Printing
693 virtual void print_on(outputStream* st) const;
694
695 virtual void oop_print_value_on(oop obj, outputStream* st);
696 virtual void oop_print_on (oop obj, outputStream* st);
697
698 virtual const char* internal_name() const = 0;
699
700 // Verification
701 virtual void verify_on(outputStream* st);
702 void verify() { verify_on(tty); }
703
704 #ifndef PRODUCT
705 bool verify_vtable_index(int index);
706 #endif
707
708 virtual void oop_verify_on(oop obj, outputStream* st);
709
710 // for error reporting
711 static bool is_valid(Klass* k);
712 };
713
714 #endif // SHARE_OOPS_KLASS_HPP