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 *
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23 */
24
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
27
28 #include "gc/shared/specialized_oop_closures.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 "trace/traceMacros.hpp"
36 #include "utilities/accessFlags.hpp"
37 #include "utilities/macros.hpp"
38
39 //
40 // A Klass provides:
41 // 1: language level class object (method dictionary etc.)
42 // 2: provide vm dispatch behavior for the object
43 // Both functions are combined into one C++ class.
44
45 // One reason for the oop/klass dichotomy in the implementation is
46 // that we don't want a C++ vtbl pointer in every object. Thus,
47 // normal oops don't have any virtual functions. Instead, they
48 // forward all "virtual" functions to their klass, which does have
49 // a vtbl and does the C++ dispatch depending on the object's
50 // actual type. (See oop.inline.hpp for some of the forwarding code.)
51 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
52
53 // Forward declarations.
54 template <class T> class Array;
55 template <class T> class GrowableArray;
56 class ClassLoaderData;
57 class fieldDescriptor;
58 class KlassSizeStats;
59 class klassVtable;
60 class ModuleEntry;
61 class PackageEntry;
62 class ParCompactionManager;
63 class PSPromotionManager;
64 class vtableEntry;
65
66 class Klass : public Metadata {
67 friend class VMStructs;
68 friend class JVMCIVMStructs;
69 protected:
70 // If you add a new field that points to any metaspace object, you
71 // must add this field to Klass::metaspace_pointers_do().
72
73 // note: put frequently-used fields together at start of klass structure
74 // for better cache behavior (may not make much of a difference but sure won't hurt)
75 enum { _primary_super_limit = 8 };
76
77 // The "layout helper" is a combined descriptor of object layout.
78 // For klasses which are neither instance nor array, the value is zero.
79 //
80 // For instances, layout helper is a positive number, the instance size.
81 // This size is already passed through align_object_size and scaled to bytes.
82 // The low order bit is set if instances of this class cannot be
83 // allocated using the fastpath.
84 //
85 // For arrays, layout helper is a negative number, containing four
86 // distinct bytes, as follows:
87 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
88 // where:
89 // tag is 0x80 if the elements are oops, 0xC0 if non-oops, 0xA0 if value types
90 // hsz is array header size in bytes (i.e., offset of first element)
91 // ebt is the BasicType of the elements
92 // esz is the element size in bytes
93 // This packed word is arranged so as to be quickly unpacked by the
94 // various fast paths that use the various subfields.
95 //
96 // The esz bits can be used directly by a SLL instruction, without masking.
97 //
98 // Note that the array-kind tag looks like 0x00 for instance klasses,
99 // since their length in bytes is always less than 24Mb.
100 //
101 // Final note: This comes first, immediately after C++ vtable,
102 // because it is frequently queried.
103 jint _layout_helper;
104
105 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
106 // and _primary_supers all help make fast subtype checks. See big discussion
107 // in doc/server_compiler/checktype.txt
108 //
109 // Where to look to observe a supertype (it is &_secondary_super_cache for
110 // secondary supers, else is &_primary_supers[depth()].
111 juint _super_check_offset;
112
113 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
114 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
115 Symbol* _name;
116
117 // Cache of last observed secondary supertype
118 Klass* _secondary_super_cache;
119 // Array of all secondary supertypes
120 Array<Klass*>* _secondary_supers;
121 // Ordered list of all primary supertypes
122 Klass* _primary_supers[_primary_super_limit];
123 // java/lang/Class instance mirroring this class
124 OopHandle _java_mirror;
125 // Superclass
126 Klass* _super;
127 // First subclass (NULL if none); _subklass->next_sibling() is next one
128 Klass* _subklass;
129 // Sibling link (or NULL); links all subklasses of a klass
130 Klass* _next_sibling;
131
132 // All klasses loaded by a class loader are chained through these links
133 Klass* _next_link;
134
135 // The VM's representation of the ClassLoader used to load this class.
136 // Provide access the corresponding instance java.lang.ClassLoader.
137 ClassLoaderData* _class_loader_data;
138
139 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
140 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
141
142 TRACE_DEFINE_TRACE_ID_FIELD;
143
144 // Biased locking implementation and statistics
145 // (the 64-bit chunk goes first, to avoid some fragmentation)
146 jlong _last_biased_lock_bulk_revocation_time;
147 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
148 jint _biased_lock_revocation_count;
149
150 // vtable length
151 int _vtable_len;
152
153 private:
154 // This is an index into FileMapHeader::_classpath_entry_table[], to
155 // associate this class with the JAR file where it's loaded from during
156 // dump time. If a class is not loaded from the shared archive, this field is
157 // -1.
158 jshort _shared_class_path_index;
159
160 friend class SharedClassUtil;
161 protected:
162
163 // Constructor
164 Klass();
165
166 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, bool is_value, TRAPS) throw();
167 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
168 return operator new (size, loader_data, word_size, false, THREAD);
169 }
170
171 public:
172 enum DefaultsLookupMode { find_defaults, skip_defaults };
173 enum OverpassLookupMode { find_overpass, skip_overpass };
174 enum StaticLookupMode { find_static, skip_static };
175 enum PrivateLookupMode { find_private, skip_private };
176
177 bool is_klass() const volatile { return true; }
178
179 // super
180 Klass* super() const { return _super; }
181 void set_super(Klass* k) { _super = k; }
182
183 // initializes _super link, _primary_supers & _secondary_supers arrays
184 void initialize_supers(Klass* k, TRAPS);
185 void initialize_supers_impl1(Klass* k);
186 void initialize_supers_impl2(Klass* k);
187
188 // klass-specific helper for initializing _secondary_supers
189 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
190
191 // java_super is the Java-level super type as specified by Class.getSuperClass.
192 virtual Klass* java_super() const { return NULL; }
193
194 juint super_check_offset() const { return _super_check_offset; }
195 void set_super_check_offset(juint o) { _super_check_offset = o; }
196
197 Klass* secondary_super_cache() const { return _secondary_super_cache; }
198 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
199
200 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
201 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
202
203 // Return the element of the _super chain of the given depth.
204 // If there is no such element, return either NULL or this.
205 Klass* primary_super_of_depth(juint i) const {
206 assert(i < primary_super_limit(), "oob");
207 Klass* super = _primary_supers[i];
208 assert(super == NULL || super->super_depth() == i, "correct display");
209 return super;
210 }
211
212 // Can this klass be a primary super? False for interfaces and arrays of
213 // interfaces. False also for arrays or classes with long super chains.
214 bool can_be_primary_super() const {
215 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
216 return super_check_offset() != secondary_offset;
217 }
218 virtual bool can_be_primary_super_slow() const;
219
220 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
221 juint super_depth() const {
222 if (!can_be_primary_super()) {
223 return primary_super_limit();
224 } else {
225 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
226 assert(d < primary_super_limit(), "oob");
227 assert(_primary_supers[d] == this, "proper init");
228 return d;
229 }
230 }
231
232 // java mirror
233 oop java_mirror() const;
234 void set_java_mirror(Handle m);
235
236 // Temporary mirror switch used by RedefineClasses
237 // Both mirrors are on the ClassLoaderData::_handles list already so no
238 // barriers are needed.
239 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; }
240 OopHandle java_mirror_handle() const { return _java_mirror; }
241
242 // modifier flags
243 jint modifier_flags() const { return _modifier_flags; }
244 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
245
246 // size helper
247 int layout_helper() const { return _layout_helper; }
248 void set_layout_helper(int lh) { _layout_helper = lh; }
249
250 // Note: for instances layout_helper() may include padding.
251 // Use InstanceKlass::contains_field_offset to classify field offsets.
252
253 // sub/superklass links
254 Klass* subklass() const { return _subklass; }
255 Klass* next_sibling() const { return _next_sibling; }
256 InstanceKlass* superklass() const;
257 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
258
259 void set_next_link(Klass* k) { _next_link = k; }
260 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
261
262 // class loader data
263 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
264 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
265
266 int shared_classpath_index() const {
267 return _shared_class_path_index;
268 };
269
270 void set_shared_classpath_index(int index) {
271 _shared_class_path_index = index;
272 };
273
274 // Obtain the module or package for this class
275 virtual ModuleEntry* module() const = 0;
276 virtual PackageEntry* package() const = 0;
277
278 protected: // internal accessors
279 void set_subklass(Klass* s);
280 void set_next_sibling(Klass* s);
281
282 public:
283
284 // Compiler support
285 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
286 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
287 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
288 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
289 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
290 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
291 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
292 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
293 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
294
295 // Unpacking layout_helper:
296 enum {
297 _lh_neutral_value = 0, // neutral non-array non-instance value
298 _lh_instance_slow_path_bit = 0x01,
299 _lh_log2_element_size_shift = BitsPerByte*0,
300 _lh_log2_element_size_mask = BitsPerLong-1,
301 _lh_element_type_shift = BitsPerByte*1,
302 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
303 _lh_header_size_shift = BitsPerByte*2,
304 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
305 _lh_array_tag_bits = 3,
306 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits
307 };
308
309 static const unsigned int _lh_array_tag_type_value = 0Xfffffffc;
310 static const unsigned int _lh_array_tag_vt_value = 0Xfffffffd;
311 static const unsigned int _lh_array_tag_obj_value = 0Xfffffffe;
312
313 static int layout_helper_size_in_bytes(jint lh) {
314 assert(lh > (jint)_lh_neutral_value, "must be instance");
315 return (int) lh & ~_lh_instance_slow_path_bit;
316 }
317 static bool layout_helper_needs_slow_path(jint lh) {
318 assert(lh > (jint)_lh_neutral_value, "must be instance");
319 return (lh & _lh_instance_slow_path_bit) != 0;
320 }
321 static bool layout_helper_is_instance(jint lh) {
322 return (jint)lh > (jint)_lh_neutral_value;
323 }
324 static bool layout_helper_is_array(jint lh) {
325 return (jint)lh < (jint)_lh_neutral_value;
326 }
327 static bool layout_helper_is_typeArray(jint lh) {
328 return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift);
329 }
330 static bool layout_helper_is_objArray(jint lh) {
331 return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift);
332 }
333 static bool layout_helper_is_valueArray(jint lh) {
334 return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift);
335 }
336 static int layout_helper_header_size(jint lh) {
337 assert(lh < (jint)_lh_neutral_value, "must be array");
338 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
339 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
340 return hsize;
341 }
342 static BasicType layout_helper_element_type(jint lh) {
343 assert(lh < (jint)_lh_neutral_value, "must be array");
344 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
345 assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_VALUETYPE, "sanity");
346 return (BasicType) btvalue;
347 }
348
349 // Want a pattern to quickly diff against layout header in register
350 // find something less clever!
351 static int layout_helper_boolean_diffbit() {
352 jint zlh = array_layout_helper(T_BOOLEAN);
353 jint blh = array_layout_helper(T_BYTE);
354 assert(zlh != blh, "array layout helpers must differ");
355 int diffbit = 1;
356 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
357 diffbit <<= 1;
358 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
359 }
360 return diffbit;
361 }
362
363 static int layout_helper_log2_element_size(jint lh) {
364 assert(lh < (jint)_lh_neutral_value, "must be array");
365 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
366 assert(layout_helper_element_type(lh) == T_VALUETYPE || l2esz <= LogBytesPerLong,
367 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
368 return l2esz;
369 }
370 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
371 return (tag << _lh_array_tag_shift)
372 | (hsize << _lh_header_size_shift)
373 | ((int)etype << _lh_element_type_shift)
374 | (log2_esize << _lh_log2_element_size_shift);
375 }
376 static jint instance_layout_helper(jint size, bool slow_path_flag) {
377 return (size << LogBytesPerWord)
378 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
379 }
380 static int layout_helper_to_size_helper(jint lh) {
381 assert(lh > (jint)_lh_neutral_value, "must be instance");
382 // Note that the following expression discards _lh_instance_slow_path_bit.
383 return lh >> LogBytesPerWord;
384 }
385 // Out-of-line version computes everything based on the etype:
386 static jint array_layout_helper(BasicType etype);
387
388 // What is the maximum number of primary superclasses any klass can have?
389 #ifdef PRODUCT
390 static juint primary_super_limit() { return _primary_super_limit; }
391 #else
392 static juint primary_super_limit() {
393 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
394 return FastSuperclassLimit;
395 }
396 #endif
397
398 // vtables
399 klassVtable vtable() const;
400 int vtable_length() const { return _vtable_len; }
401
402 // subclass check
403 bool is_subclass_of(const Klass* k) const;
404 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
405 bool is_subtype_of(Klass* k) const {
406 juint off = k->super_check_offset();
407 Klass* sup = *(Klass**)( (address)this + off );
408 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
409 if (sup == k) {
410 return true;
411 } else if (off != secondary_offset) {
412 return false;
413 } else {
414 return search_secondary_supers(k);
415 }
416 }
417
418 // Is an oop/narrowOop null or subtype of this Klass?
419 template <typename T>
420 bool is_instanceof_or_null(T element);
421
422 bool search_secondary_supers(Klass* k) const;
423
424 // Find LCA in class hierarchy
425 Klass *LCA( Klass *k );
426
427 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
428 // if not, throw either an Error or an Exception.
429 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
430
431 // array copying
432 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
433
434 // tells if the class should be initialized
435 virtual bool should_be_initialized() const { return false; }
436 // initializes the klass
437 virtual void initialize(TRAPS);
438 // lookup operation for MethodLookupCache
439 friend class MethodLookupCache;
440 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
441 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const;
442 public:
443 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
444 return uncached_lookup_method(name, signature, find_overpass);
445 }
446
447 // array class with specific rank
448 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
449
450 // array class with this klass as element type
451 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
452
453 // These will return NULL instead of allocating on the heap:
454 // NB: these can block for a mutex, like other functions with TRAPS arg.
455 Klass* array_klass_or_null(int rank);
456 Klass* array_klass_or_null();
457
458 virtual oop protection_domain() const = 0;
459
460 oop class_loader() const;
461
462 virtual oop klass_holder() const { return class_loader(); }
463
464 protected:
465 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
466 virtual Klass* array_klass_impl(bool or_null, TRAPS);
467
468 void set_vtable_length(int len) { _vtable_len= len; }
469
470 vtableEntry* start_of_vtable() const;
471 public:
472 Method* method_at_vtable(int index);
473
474 static ByteSize vtable_start_offset();
475 static ByteSize vtable_length_offset() {
476 return byte_offset_of(Klass, _vtable_len);
477 }
478
479 // CDS support - remove and restore oops from metadata. Oops are not shared.
480 virtual void remove_unshareable_info();
481 virtual void remove_java_mirror();
482 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
483
484 protected:
485 // computes the subtype relationship
486 virtual bool compute_is_subtype_of(Klass* k);
487 public:
488 // subclass accessor (here for convenience; undefined for non-klass objects)
489 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
490 public:
491 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
492 // These functions describe behavior for the oop not the KLASS.
493
494 // actual oop size of obj in memory
495 virtual int oop_size(oop obj) const = 0;
496
497 // Size of klass in word size.
498 virtual int size() const = 0;
499 #if INCLUDE_SERVICES
500 virtual void collect_statistics(KlassSizeStats *sz) const;
501 #endif
502
503 // Returns the Java name for a class (Resource allocated)
504 // For arrays, this returns the name of the element with a leading '['.
505 // For classes, this returns the name with the package separators
506 // turned into '.'s.
507 const char* external_name() const;
508 // Returns the name for a class (Resource allocated) as the class
509 // would appear in a signature.
510 // For arrays, this returns the name of the element with a leading '['.
511 // For classes, this returns the name with a leading 'L' and a trailing ';'
512 // and the package separators as '/'.
513 virtual const char* signature_name() const;
514
515 const char* class_loader_and_module_name() const;
516
517 // type testing operations
518 #ifdef ASSERT
519 protected:
520 virtual bool is_instance_klass_slow() const { return false; }
521 virtual bool is_array_klass_slow() const { return false; }
522 virtual bool is_objArray_klass_slow() const { return false; }
523 virtual bool is_typeArray_klass_slow() const { return false; }
524 virtual bool is_valueArray_klass_slow() const { return false; }
525 #endif // ASSERT
526 // current implementation uses this method even in non debug builds
527 virtual bool is_value_slow() const { return false; }
528 public:
529
530 // Fast non-virtual versions
531 #ifndef ASSERT
532 #define assert_same_query(xval, xcheck) xval
533 #else
534 private:
535 static bool assert_same_query(bool xval, bool xslow) {
536 assert(xval == xslow, "slow and fast queries agree");
537 return xval;
538 }
539 public:
540 #endif
541 inline bool is_instance_klass() const { return assert_same_query(
542 layout_helper_is_instance(layout_helper()),
543 is_instance_klass_slow()); }
544 inline bool is_array_klass() const { return assert_same_query(
545 layout_helper_is_array(layout_helper()),
546 is_array_klass_slow()); }
547 inline bool is_objArray_klass() const { return assert_same_query(
548 layout_helper_is_objArray(layout_helper()),
549 is_objArray_klass_slow()); }
550 inline bool is_typeArray_klass() const { return assert_same_query(
551 layout_helper_is_typeArray(layout_helper()),
552 is_typeArray_klass_slow()); }
553 inline bool is_value() const { return is_value_slow(); } //temporary hack
554 inline bool is_valueArray_klass() const { return assert_same_query(
555 layout_helper_is_valueArray(layout_helper()),
556 is_valueArray_klass_slow()); }
557
558 #undef assert_same_query
559
560 // Access flags
561 AccessFlags access_flags() const { return _access_flags; }
562 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
563
564 bool is_public() const { return _access_flags.is_public(); }
565 bool is_final() const { return _access_flags.is_final(); }
566 bool is_interface() const { return _access_flags.is_interface(); }
567 bool is_abstract() const { return _access_flags.is_abstract(); }
568 bool is_super() const { return _access_flags.is_super(); }
569 bool is_synthetic() const { return _access_flags.is_synthetic(); }
570 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
571 bool has_finalizer() const { return _access_flags.has_finalizer(); }
572 bool has_final_method() const { return _access_flags.has_final_method(); }
573 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
574 void set_has_final_method() { _access_flags.set_has_final_method(); }
575 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
576 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
577 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
578 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
579 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
580 void set_is_shared() { _access_flags.set_is_shared_class(); }
581
582 bool is_cloneable() const;
583 void set_is_cloneable();
584
585 // Biased locking support
586 // Note: the prototype header is always set up to be at least the
587 // prototype markOop. If biased locking is enabled it may further be
588 // biasable and have an epoch.
589 markOop prototype_header() const { return _prototype_header; }
590 static inline markOop default_prototype_header(Klass* k) {
591 return (k == NULL) ? markOopDesc::prototype() : k->prototype_header();
592 }
593 // NOTE: once instances of this klass are floating around in the
594 // system, this header must only be updated at a safepoint.
595 // NOTE 2: currently we only ever set the prototype header to the
596 // biasable prototype for instanceKlasses. There is no technical
597 // reason why it could not be done for arrayKlasses aside from
598 // wanting to reduce the initial scope of this optimization. There
599 // are potential problems in setting the bias pattern for
600 // JVM-internal oops.
601 inline void set_prototype_header(markOop header);
602 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
603
604 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
605 // Atomically increments biased_lock_revocation_count and returns updated value
606 int atomic_incr_biased_lock_revocation_count();
607 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
608 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
609 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
610
611 TRACE_DEFINE_TRACE_ID_METHODS;
612
613 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
614 virtual MetaspaceObj::Type type() const { return ClassType; }
615
616 // Iff the class loader (or mirror for anonymous classes) is alive the
617 // Klass is considered alive.
618 // The is_alive closure passed in depends on the Garbage Collector used.
619 bool is_loader_alive(BoolObjectClosure* is_alive);
620
621 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true);
622 static void clean_subklass_tree(BoolObjectClosure* is_alive) {
623 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */);
624 }
625
626 // GC specific object visitors
627 //
628 #if INCLUDE_ALL_GCS
629 // Parallel Scavenge
630 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0;
631 // Parallel Compact
632 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0;
633 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0;
634 #endif
635
636 // Iterators specialized to particular subtypes
637 // of ExtendedOopClosure, to avoid closure virtual calls.
638 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
639 virtual void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) = 0; \
640 /* Iterates "closure" over all the oops in "obj" (of type "this") within "mr". */ \
641 virtual void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) = 0;
642
643 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
644 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
645
646 #if INCLUDE_ALL_GCS
647 #define Klass_OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
648 virtual void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) = 0;
649
650 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
651 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
652 #endif // INCLUDE_ALL_GCS
653
654 virtual void array_klasses_do(void f(Klass* k)) {}
655
656 // Return self, except for abstract classes with exactly 1
657 // implementor. Then return the 1 concrete implementation.
658 Klass *up_cast_abstract();
659
660 // klass name
661 Symbol* name() const { return _name; }
662 void set_name(Symbol* n);
663
664 public:
665 // jvm support
666 virtual jint compute_modifier_flags(TRAPS) const;
667
668 // JVMTI support
669 virtual jint jvmti_class_status() const;
670
671 // Printing
672 virtual void print_on(outputStream* st) const;
673
674 virtual void oop_print_value_on(oop obj, outputStream* st);
675 virtual void oop_print_on (oop obj, outputStream* st);
676
677 virtual const char* internal_name() const = 0;
678
679 // Verification
680 virtual void verify_on(outputStream* st);
681 void verify() { verify_on(tty); }
682
683 #ifndef PRODUCT
684 bool verify_vtable_index(int index);
685 bool verify_itable_index(int index);
686 #endif
687
688 virtual void oop_verify_on(oop obj, outputStream* st);
689
690 static bool is_null(narrowKlass obj);
691 static bool is_null(Klass* obj);
692
693 // klass encoding for klass pointer in objects.
694 static narrowKlass encode_klass_not_null(Klass* v);
695 static narrowKlass encode_klass(Klass* v);
696
697 static Klass* decode_klass_not_null(narrowKlass v);
698 static Klass* decode_klass(narrowKlass v);
699
700 static bool decode_ptr_is_value_type(narrowKlass v);
701 static bool ptr_is_value_type(Klass* v);
702 };
703
704 // Helper to convert the oop iterate macro suffixes into bool values that can be used by template functions.
705 #define nvs_nv_to_bool true
706 #define nvs_v_to_bool false
707 #define nvs_to_bool(nv_suffix) nvs##nv_suffix##_to_bool
708
709 // Oop iteration macros for declarations.
710 // Used to generate declarations in the *Klass header files.
711
712 #define OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
713 void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure); \
714 void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr);
715
716 #if INCLUDE_ALL_GCS
717 #define OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
718 void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure);
719 #endif // INCLUDE_ALL_GCS
720
721
722 // Oop iteration macros for definitions.
723 // Used to generate definitions in the *Klass.inline.hpp files.
724
725 #define OOP_OOP_ITERATE_DEFN(KlassType, OopClosureType, nv_suffix) \
726 void KlassType::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
727 oop_oop_iterate<nvs_to_bool(nv_suffix)>(obj, closure); \
728 }
729
730 #if INCLUDE_ALL_GCS
731 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) \
732 void KlassType::oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \
733 oop_oop_iterate_reverse<nvs_to_bool(nv_suffix)>(obj, closure); \
734 }
735 #else
736 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix)
737 #endif
738
739 #define OOP_OOP_ITERATE_DEFN_BOUNDED(KlassType, OopClosureType, nv_suffix) \
740 void KlassType::oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) { \
741 oop_oop_iterate_bounded<nvs_to_bool(nv_suffix)>(obj, closure, mr); \
742 }
743
744 #endif // SHARE_VM_OOPS_KLASS_HPP