1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
27
28 #include "classfile/classLoaderData.hpp"
29 #include "gc/shared/specialized_oop_closures.hpp"
30 #include "memory/iterator.hpp"
31 #include "memory/memRegion.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 //
42 // A Klass provides:
43 // 1: language level class object (method dictionary etc.)
44 // 2: provide vm dispatch behavior for the object
45 // Both functions are combined into one C++ class.
46
47 // One reason for the oop/klass dichotomy in the implementation is
48 // that we don't want a C++ vtbl pointer in every object. Thus,
49 // normal oops don't have any virtual functions. Instead, they
50 // forward all "virtual" functions to their klass, which does have
51 // a vtbl and does the C++ dispatch depending on the object's
52 // actual type. (See oop.inline.hpp for some of the forwarding code.)
53 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
54
55 // Forward declarations.
56 template <class T> class Array;
57 template <class T> class GrowableArray;
58 class fieldDescriptor;
59 class KlassSizeStats;
60 class klassVtable;
61 class ModuleEntry;
62 class PackageEntry;
63 class ParCompactionManager;
64 class PSPromotionManager;
65 class vtableEntry;
66
67 class Klass : public Metadata {
68 friend class VMStructs;
69 friend class JVMCIVMStructs;
70 protected:
71 // If you add a new field that points to any metaspace object, you
72 // must add this field to Klass::metaspace_pointers_do().
73
74 // note: put frequently-used fields together at start of klass structure
75 // for better cache behavior (may not make much of a difference but sure won't hurt)
76 enum { _primary_super_limit = 8 };
77
78 // The "layout helper" is a combined descriptor of object layout.
79 // For klasses which are neither instance nor array, the value is zero.
80 //
81 // For instances, layout helper is a positive number, the instance size.
82 // This size is already passed through align_object_size and scaled to bytes.
83 // The low order bit is set if instances of this class cannot be
84 // allocated using the fastpath.
85 //
86 // For arrays, layout helper is a negative number, containing four
87 // distinct bytes, as follows:
88 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
89 // where:
90 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
91 // hsz is array header size in bytes (i.e., offset of first element)
92 // ebt is the BasicType of the elements
93 // esz is the element size in bytes
94 // This packed word is arranged so as to be quickly unpacked by the
95 // various fast paths that use the various subfields.
96 //
97 // The esz bits can be used directly by a SLL instruction, without masking.
98 //
99 // Note that the array-kind tag looks like 0x00 for instance klasses,
100 // since their length in bytes is always less than 24Mb.
101 //
102 // Final note: This comes first, immediately after C++ vtable,
103 // because it is frequently queried.
104 jint _layout_helper;
105
106 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
107 // and _primary_supers all help make fast subtype checks. See big discussion
108 // in doc/server_compiler/checktype.txt
109 //
110 // Where to look to observe a supertype (it is &_secondary_super_cache for
111 // secondary supers, else is &_primary_supers[depth()].
112 juint _super_check_offset;
113
114 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
115 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
116 Symbol* _name;
117
118 // Cache of last observed secondary supertype
119 Klass* _secondary_super_cache;
120 // Array of all secondary supertypes
121 Array<Klass*>* _secondary_supers;
122 // Ordered list of all primary supertypes
123 Klass* _primary_supers[_primary_super_limit];
124 // java/lang/Class instance mirroring this class
125 OopHandle _java_mirror;
126 // Superclass
127 Klass* _super;
128 // First subclass (NULL if none); _subklass->next_sibling() is next one
129 Klass* _subklass;
130 // Sibling link (or NULL); links all subklasses of a klass
131 Klass* _next_sibling;
132
133 // All klasses loaded by a class loader are chained through these links
134 Klass* _next_link;
135
136 // The VM's representation of the ClassLoader used to load this class.
137 // Provide access the corresponding instance java.lang.ClassLoader.
138 ClassLoaderData* _class_loader_data;
139
140 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
141 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
142
143 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
144
145 // Biased locking implementation and statistics
146 // (the 64-bit chunk goes first, to avoid some fragmentation)
147 jlong _last_biased_lock_bulk_revocation_time;
148 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
149 jint _biased_lock_revocation_count;
150
151 // vtable length
152 int _vtable_len;
153
154 private:
155 // This is an index into FileMapHeader::_shared_path_table[], to
156 // associate this class with the JAR file where it's loaded from during
157 // dump time. If a class is not loaded from the shared archive, this field is
158 // -1.
159 jshort _shared_class_path_index;
160
161 #if INCLUDE_CDS
162 // Flags of the current shared class.
163 u2 _shared_class_flags;
164 enum {
165 _has_raw_archived_mirror = 1,
166 _has_signer_and_not_archived = 1 << 2
167 };
168 #endif
169 // The _archived_mirror is set at CDS dump time pointing to the cached mirror
170 // in the open archive heap region when archiving java object is supported.
171 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;)
172
173 protected:
174
175 // Constructor
176 Klass();
177
178 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
179
180 public:
181 enum DefaultsLookupMode { find_defaults, skip_defaults };
182 enum OverpassLookupMode { find_overpass, skip_overpass };
183 enum StaticLookupMode { find_static, skip_static };
184 enum PrivateLookupMode { find_private, skip_private };
185
186 bool is_klass() const volatile { return true; }
187
188 // super
189 Klass* super() const { return _super; }
190 void set_super(Klass* k) { _super = k; }
191
192 // initializes _super link, _primary_supers & _secondary_supers arrays
193 void initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS);
194 void initialize_supers_impl1(Klass* k);
195 void initialize_supers_impl2(Klass* k);
196
197 // klass-specific helper for initializing _secondary_supers
198 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
199 Array<Klass*>* transitive_interfaces);
200
201 // java_super is the Java-level super type as specified by Class.getSuperClass.
202 virtual Klass* java_super() const { return NULL; }
203
204 juint super_check_offset() const { return _super_check_offset; }
205 void set_super_check_offset(juint o) { _super_check_offset = o; }
206
207 Klass* secondary_super_cache() const { return _secondary_super_cache; }
208 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
209
210 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
211 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
212
213 // Return the element of the _super chain of the given depth.
214 // If there is no such element, return either NULL or this.
215 Klass* primary_super_of_depth(juint i) const {
216 assert(i < primary_super_limit(), "oob");
217 Klass* super = _primary_supers[i];
218 assert(super == NULL || super->super_depth() == i, "correct display");
219 return super;
220 }
221
222 // Can this klass be a primary super? False for interfaces and arrays of
223 // interfaces. False also for arrays or classes with long super chains.
224 bool can_be_primary_super() const {
225 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
226 return super_check_offset() != secondary_offset;
227 }
228 virtual bool can_be_primary_super_slow() const;
229
230 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
231 juint super_depth() const {
232 if (!can_be_primary_super()) {
233 return primary_super_limit();
234 } else {
235 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
236 assert(d < primary_super_limit(), "oob");
237 assert(_primary_supers[d] == this, "proper init");
238 return d;
239 }
240 }
241
242 // java mirror
243 oop java_mirror() const;
244 void set_java_mirror(Handle m);
245
246 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier
247 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // accessor with GC barrier
248 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier
249
250 // Temporary mirror switch used by RedefineClasses
251 // Both mirrors are on the ClassLoaderData::_handles list already so no
252 // barriers are needed.
253 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; }
254 OopHandle java_mirror_handle() const {
255 return _java_mirror;
256 }
257
258 // modifier flags
259 jint modifier_flags() const { return _modifier_flags; }
260 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
261
262 // size helper
263 int layout_helper() const { return _layout_helper; }
264 void set_layout_helper(int lh) { _layout_helper = lh; }
265
266 // Note: for instances layout_helper() may include padding.
267 // Use InstanceKlass::contains_field_offset to classify field offsets.
268
269 // sub/superklass links
270 Klass* subklass() const { return _subklass; }
271 Klass* next_sibling() const { return _next_sibling; }
272 InstanceKlass* superklass() const;
273 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
274
275 void set_next_link(Klass* k) { _next_link = k; }
276 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
277
278 // class loader data
279 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
280 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
281
282 int shared_classpath_index() const {
283 return _shared_class_path_index;
284 };
285
286 void set_shared_classpath_index(int index) {
287 _shared_class_path_index = index;
288 };
289
290 void set_has_raw_archived_mirror() {
291 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;)
292 }
293 void clear_has_raw_archived_mirror() {
294 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;)
295 }
296 bool has_raw_archived_mirror() const {
297 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;)
298 NOT_CDS(return false;)
299 }
300 #if INCLUDE_CDS
301 void set_has_signer_and_not_archived() {
302 _shared_class_flags |= _has_signer_and_not_archived;
303 }
304 bool has_signer_and_not_archived() const {
305 assert(DumpSharedSpaces, "dump time only");
306 return (_shared_class_flags & _has_signer_and_not_archived) != 0;
307 }
308 #endif // INCLUDE_CDS
309
310 // Obtain the module or package for this class
311 virtual ModuleEntry* module() const = 0;
312 virtual PackageEntry* package() const = 0;
313
314 protected: // internal accessors
315 void set_subklass(Klass* s);
316 void set_next_sibling(Klass* s);
317
318 public:
319
320 // Compiler support
321 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
322 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
323 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
324 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
325 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
326 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
327 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
328 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
329 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
330
331 // Unpacking layout_helper:
332 enum {
333 _lh_neutral_value = 0, // neutral non-array non-instance value
334 _lh_instance_slow_path_bit = 0x01,
335 _lh_log2_element_size_shift = BitsPerByte*0,
336 _lh_log2_element_size_mask = BitsPerLong-1,
337 _lh_element_type_shift = BitsPerByte*1,
338 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
339 _lh_header_size_shift = BitsPerByte*2,
340 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
341 _lh_array_tag_bits = 2,
342 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
343 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
344 };
345
346 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
347
348 static int layout_helper_size_in_bytes(jint lh) {
349 assert(lh > (jint)_lh_neutral_value, "must be instance");
350 return (int) lh & ~_lh_instance_slow_path_bit;
351 }
352 static bool layout_helper_needs_slow_path(jint lh) {
353 assert(lh > (jint)_lh_neutral_value, "must be instance");
354 return (lh & _lh_instance_slow_path_bit) != 0;
355 }
356 static bool layout_helper_is_instance(jint lh) {
357 return (jint)lh > (jint)_lh_neutral_value;
358 }
359 static bool layout_helper_is_array(jint lh) {
360 return (jint)lh < (jint)_lh_neutral_value;
361 }
362 static bool layout_helper_is_typeArray(jint lh) {
363 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
364 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
365 }
366 static bool layout_helper_is_objArray(jint lh) {
367 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
368 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
369 }
370 static int layout_helper_header_size(jint lh) {
371 assert(lh < (jint)_lh_neutral_value, "must be array");
372 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
373 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
374 return hsize;
375 }
376 static BasicType layout_helper_element_type(jint lh) {
377 assert(lh < (jint)_lh_neutral_value, "must be array");
378 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
379 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
380 return (BasicType) btvalue;
381 }
382
383 // Want a pattern to quickly diff against layout header in register
384 // find something less clever!
385 static int layout_helper_boolean_diffbit() {
386 jint zlh = array_layout_helper(T_BOOLEAN);
387 jint blh = array_layout_helper(T_BYTE);
388 assert(zlh != blh, "array layout helpers must differ");
389 int diffbit = 1;
390 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
391 diffbit <<= 1;
392 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
393 }
394 return diffbit;
395 }
396
397 static int layout_helper_log2_element_size(jint lh) {
398 assert(lh < (jint)_lh_neutral_value, "must be array");
399 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
400 assert(l2esz <= LogBytesPerLong,
401 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
402 return l2esz;
403 }
404 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
405 return (tag << _lh_array_tag_shift)
406 | (hsize << _lh_header_size_shift)
407 | ((int)etype << _lh_element_type_shift)
408 | (log2_esize << _lh_log2_element_size_shift);
409 }
410 static jint instance_layout_helper(jint size, bool slow_path_flag) {
411 return (size << LogBytesPerWord)
412 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
413 }
414 static int layout_helper_to_size_helper(jint lh) {
415 assert(lh > (jint)_lh_neutral_value, "must be instance");
416 // Note that the following expression discards _lh_instance_slow_path_bit.
417 return lh >> LogBytesPerWord;
418 }
419 // Out-of-line version computes everything based on the etype:
420 static jint array_layout_helper(BasicType etype);
421
422 // What is the maximum number of primary superclasses any klass can have?
423 #ifdef PRODUCT
424 static juint primary_super_limit() { return _primary_super_limit; }
425 #else
426 static juint primary_super_limit() {
427 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
428 return FastSuperclassLimit;
429 }
430 #endif
431
432 // vtables
433 klassVtable vtable() const;
434 int vtable_length() const { return _vtable_len; }
435
436 // subclass check
437 bool is_subclass_of(const Klass* k) const;
438 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
439 bool is_subtype_of(Klass* k) const {
440 juint off = k->super_check_offset();
441 Klass* sup = *(Klass**)( (address)this + off );
442 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
443 if (sup == k) {
444 return true;
445 } else if (off != secondary_offset) {
446 return false;
447 } else {
448 return search_secondary_supers(k);
449 }
450 }
451
452 bool search_secondary_supers(Klass* k) const;
453
454 // Find LCA in class hierarchy
455 Klass *LCA( Klass *k );
456
457 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
458 // if not, throw either an Error or an Exception.
459 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
460
461 // array copying
462 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
463
464 // tells if the class should be initialized
465 virtual bool should_be_initialized() const { return false; }
466 // initializes the klass
467 virtual void initialize(TRAPS);
468 // lookup operation for MethodLookupCache
469 friend class MethodLookupCache;
470 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
471 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const;
472 public:
473 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
474 return uncached_lookup_method(name, signature, find_overpass);
475 }
476
477 // array class with specific rank
478 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
479
480 // array class with this klass as element type
481 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
482
483 // These will return NULL instead of allocating on the heap:
484 // NB: these can block for a mutex, like other functions with TRAPS arg.
485 Klass* array_klass_or_null(int rank);
486 Klass* array_klass_or_null();
487
488 virtual oop protection_domain() const = 0;
489
490 oop class_loader() const;
491
492 virtual oop klass_holder() const { return class_loader(); }
493
494 protected:
495 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
496 virtual Klass* array_klass_impl(bool or_null, TRAPS);
497
498 void set_vtable_length(int len) { _vtable_len= len; }
499
500 vtableEntry* start_of_vtable() const;
501 public:
502 Method* method_at_vtable(int index);
503
504 static ByteSize vtable_start_offset();
505 static ByteSize vtable_length_offset() {
506 return byte_offset_of(Klass, _vtable_len);
507 }
508
509 // CDS support - remove and restore oops from metadata. Oops are not shared.
510 virtual void remove_unshareable_info();
511 virtual void remove_java_mirror();
512 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
513
514 protected:
515 // computes the subtype relationship
516 virtual bool compute_is_subtype_of(Klass* k);
517 public:
518 // subclass accessor (here for convenience; undefined for non-klass objects)
519 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
520 public:
521 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
522 // These functions describe behavior for the oop not the KLASS.
523
524 // actual oop size of obj in memory
525 virtual int oop_size(oop obj) const = 0;
526
527 // Size of klass in word size.
528 virtual int size() const = 0;
529 #if INCLUDE_SERVICES
530 virtual void collect_statistics(KlassSizeStats *sz) const;
531 #endif
532
533 // Returns the Java name for a class (Resource allocated)
534 // For arrays, this returns the name of the element with a leading '['.
535 // For classes, this returns the name with the package separators
536 // turned into '.'s.
537 const char* external_name() const;
538 // Returns the name for a class (Resource allocated) as the class
539 // would appear in a signature.
540 // For arrays, this returns the name of the element with a leading '['.
541 // For classes, this returns the name with a leading 'L' and a trailing ';'
542 // and the package separators as '/'.
543 virtual const char* signature_name() const;
544
545 const char* class_loader_and_module_name() const;
546
547 // Returns "interface", "abstract class" or "class".
548 const char* external_kind() const;
549
550 // type testing operations
551 #ifdef ASSERT
552 protected:
553 virtual bool is_instance_klass_slow() const { return false; }
554 virtual bool is_array_klass_slow() const { return false; }
555 virtual bool is_objArray_klass_slow() const { return false; }
556 virtual bool is_typeArray_klass_slow() const { return false; }
557 #endif // ASSERT
558 public:
559
560 // Fast non-virtual versions
561 #ifndef ASSERT
562 #define assert_same_query(xval, xcheck) xval
563 #else
564 private:
565 static bool assert_same_query(bool xval, bool xslow) {
566 assert(xval == xslow, "slow and fast queries agree");
567 return xval;
568 }
569 public:
570 #endif
571 inline bool is_instance_klass() const { return assert_same_query(
572 layout_helper_is_instance(layout_helper()),
573 is_instance_klass_slow()); }
574 inline bool is_array_klass() const { return assert_same_query(
575 layout_helper_is_array(layout_helper()),
576 is_array_klass_slow()); }
577 inline bool is_objArray_klass() const { return assert_same_query(
578 layout_helper_is_objArray(layout_helper()),
579 is_objArray_klass_slow()); }
580 inline bool is_typeArray_klass() const { return assert_same_query(
581 layout_helper_is_typeArray(layout_helper()),
582 is_typeArray_klass_slow()); }
583 #undef assert_same_query
584
585 // Access flags
586 AccessFlags access_flags() const { return _access_flags; }
587 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
588
589 bool is_public() const { return _access_flags.is_public(); }
590 bool is_final() const { return _access_flags.is_final(); }
591 bool is_interface() const { return _access_flags.is_interface(); }
592 bool is_abstract() const { return _access_flags.is_abstract(); }
593 bool is_super() const { return _access_flags.is_super(); }
594 bool is_synthetic() const { return _access_flags.is_synthetic(); }
595 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
596 bool has_finalizer() const { return _access_flags.has_finalizer(); }
597 bool has_final_method() const { return _access_flags.has_final_method(); }
598 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
599 void set_has_final_method() { _access_flags.set_has_final_method(); }
600 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
601 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
602 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
603 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
604 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
605 void set_is_shared() { _access_flags.set_is_shared_class(); }
606
607 bool is_cloneable() const;
608 void set_is_cloneable();
609
610 // Biased locking support
611 // Note: the prototype header is always set up to be at least the
612 // prototype markOop. If biased locking is enabled it may further be
613 // biasable and have an epoch.
614 markOop prototype_header() const { return _prototype_header; }
615 // NOTE: once instances of this klass are floating around in the
616 // system, this header must only be updated at a safepoint.
617 // NOTE 2: currently we only ever set the prototype header to the
618 // biasable prototype for instanceKlasses. There is no technical
619 // reason why it could not be done for arrayKlasses aside from
620 // wanting to reduce the initial scope of this optimization. There
621 // are potential problems in setting the bias pattern for
622 // JVM-internal oops.
623 inline void set_prototype_header(markOop header);
624 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
625
626 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
627 // Atomically increments biased_lock_revocation_count and returns updated value
628 int atomic_incr_biased_lock_revocation_count();
629 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
630 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
631 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
632
633 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
634
635 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
636 virtual MetaspaceObj::Type type() const { return ClassType; }
637
638 // Iff the class loader (or mirror for anonymous classes) is alive the
639 // Klass is considered alive. Has already been marked as unloading.
640 bool is_loader_alive() const { return !class_loader_data()->is_unloading(); }
641
642 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
643 static void clean_subklass_tree() {
644 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
645 }
646
647 // GC specific object visitors
648 //
649 #if INCLUDE_PARALLELGC
650 // Parallel Scavenge
651 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0;
652 // Parallel Compact
653 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0;
654 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0;
655 #endif
656
657 // Iterators specialized to particular subtypes
658 // of ExtendedOopClosure, to avoid closure virtual calls.
659 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
660 virtual void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) = 0; \
661 /* Iterates "closure" over all the oops in "obj" (of type "this") within "mr". */ \
662 virtual void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) = 0;
663
664 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
665 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
666
667 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS
668 #define Klass_OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
669 virtual void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) = 0;
670
671 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
672 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
673 #endif
674
675 virtual void array_klasses_do(void f(Klass* k)) {}
676
677 // Return self, except for abstract classes with exactly 1
678 // implementor. Then return the 1 concrete implementation.
679 Klass *up_cast_abstract();
680
681 // klass name
682 Symbol* name() const { return _name; }
683 void set_name(Symbol* n);
684
685 public:
686 // jvm support
687 virtual jint compute_modifier_flags(TRAPS) const;
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 bool verify_itable_index(int index);
707 #endif
708
709 virtual void oop_verify_on(oop obj, outputStream* st);
710
711 static bool is_null(narrowKlass obj);
712 static bool is_null(Klass* obj);
713
714 // klass encoding for klass pointer in objects.
715 static narrowKlass encode_klass_not_null(Klass* v);
716 static narrowKlass encode_klass(Klass* v);
717
718 static Klass* decode_klass_not_null(narrowKlass v);
719 static Klass* decode_klass(narrowKlass v);
720 };
721
722 // Helper to convert the oop iterate macro suffixes into bool values that can be used by template functions.
723 #define nvs_nv_to_bool true
724 #define nvs_v_to_bool false
725 #define nvs_to_bool(nv_suffix) nvs##nv_suffix##_to_bool
726
727 // Oop iteration macros for declarations.
728 // Used to generate declarations in the *Klass header files.
729
730 #define OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
731 void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure); \
732 void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr);
733
734 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS
735 #define OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
736 void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure);
737 #endif
738
739
740 // Oop iteration macros for definitions.
741 // Used to generate definitions in the *Klass.inline.hpp files.
742
743 #define OOP_OOP_ITERATE_DEFN(KlassType, OopClosureType, nv_suffix) \
744 void KlassType::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
745 oop_oop_iterate<nvs_to_bool(nv_suffix)>(obj, closure); \
746 }
747
748 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS
749 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) \
750 void KlassType::oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \
751 oop_oop_iterate_reverse<nvs_to_bool(nv_suffix)>(obj, closure); \
752 }
753 #else
754 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix)
755 #endif
756
757 #define OOP_OOP_ITERATE_DEFN_BOUNDED(KlassType, OopClosureType, nv_suffix) \
758 void KlassType::oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) { \
759 oop_oop_iterate_bounded<nvs_to_bool(nv_suffix)>(obj, closure, mr); \
760 }
761
762 #endif // SHARE_VM_OOPS_KLASS_HPP