1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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).
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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/metadata.hpp"
32 #include "oops/oop.hpp"
33 #include "trace/traceMacros.hpp"
34 #include "utilities/accessFlags.hpp"
35 #include "utilities/macros.hpp"
36
37 //
38 // A Klass provides:
39 // 1: language level class object (method dictionary etc.)
40 // 2: provide vm dispatch behavior for the object
41 // Both functions are combined into one C++ class.
42
43 // One reason for the oop/klass dichotomy in the implementation is
44 // that we don't want a C++ vtbl pointer in every object. Thus,
45 // normal oops don't have any virtual functions. Instead, they
46 // forward all "virtual" functions to their klass, which does have
47 // a vtbl and does the C++ dispatch depending on the object's
48 // actual type. (See oop.inline.hpp for some of the forwarding code.)
49 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
50
51 // Forward declarations.
52 template <class T> class Array;
53 template <class T> class GrowableArray;
54 class ClassLoaderData;
55 class fieldDescriptor;
56 class KlassSizeStats;
57 class klassVtable;
58 class ModuleEntry;
59 class PackageEntry;
60 class ParCompactionManager;
61 class PSPromotionManager;
62 class vtableEntry;
63
64 class Klass : public Metadata {
65 friend class VMStructs;
66 friend class JVMCIVMStructs;
67 protected:
68 // If you add a new field that points to any metaspace object, you
69 // must add this field to Klass::metaspace_pointers_do().
70
71 // note: put frequently-used fields together at start of klass structure
72 // for better cache behavior (may not make much of a difference but sure won't hurt)
73 enum { _primary_super_limit = 8 };
74
75 // The "layout helper" is a combined descriptor of object layout.
76 // For klasses which are neither instance nor array, the value is zero.
77 //
78 // For instances, layout helper is a positive number, the instance size.
79 // This size is already passed through align_object_size and scaled to bytes.
80 // The low order bit is set if instances of this class cannot be
81 // allocated using the fastpath.
82 //
83 // For arrays, layout helper is a negative number, containing four
84 // distinct bytes, as follows:
85 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
86 // where:
87 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
88 // hsz is array header size in bytes (i.e., offset of first element)
89 // ebt is the BasicType of the elements
90 // esz is the element size in bytes
91 // This packed word is arranged so as to be quickly unpacked by the
92 // various fast paths that use the various subfields.
93 //
94 // The esz bits can be used directly by a SLL instruction, without masking.
95 //
96 // Note that the array-kind tag looks like 0x00 for instance klasses,
97 // since their length in bytes is always less than 24Mb.
98 //
99 // Final note: This comes first, immediately after C++ vtable,
100 // because it is frequently queried.
101 jint _layout_helper;
102
103 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
104 // and _primary_supers all help make fast subtype checks. See big discussion
105 // in doc/server_compiler/checktype.txt
106 //
107 // Where to look to observe a supertype (it is &_secondary_super_cache for
108 // secondary supers, else is &_primary_supers[depth()].
109 juint _super_check_offset;
110
111 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
112 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
113 Symbol* _name;
114
115 // Cache of last observed secondary supertype
116 Klass* _secondary_super_cache;
117 // Array of all secondary supertypes
118 Array<Klass*>* _secondary_supers;
119 // Ordered list of all primary supertypes
120 Klass* _primary_supers[_primary_super_limit];
121 // java/lang/Class instance mirroring this class
122 oop _java_mirror;
123 // Superclass
124 Klass* _super;
125 // First subclass (NULL if none); _subklass->next_sibling() is next one
126 Klass* _subklass;
127 // Sibling link (or NULL); links all subklasses of a klass
128 Klass* _next_sibling;
129
130 // All klasses loaded by a class loader are chained through these links
131 Klass* _next_link;
132
133 // The VM's representation of the ClassLoader used to load this class.
134 // Provide access the corresponding instance java.lang.ClassLoader.
135 ClassLoaderData* _class_loader_data;
136
137 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
138 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
139
140 TRACE_DEFINE_TRACE_ID_FIELD;
141
142 // Biased locking implementation and statistics
143 // (the 64-bit chunk goes first, to avoid some fragmentation)
144 jlong _last_biased_lock_bulk_revocation_time;
145 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
146 jint _biased_lock_revocation_count;
147
148 // vtable length
149 int _vtable_len;
150
151 // Remembered sets support for the oops in the klasses.
152 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support)
153 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
154
155 private:
156 // This is an index into FileMapHeader::_classpath_entry_table[], to
157 // associate this class with the JAR file where it's loaded from during
158 // dump time. If a class is not loaded from the shared archive, this field is
159 // -1.
160 jshort _shared_class_path_index;
161
162 friend class SharedClassUtil;
163 protected:
164
165 // Constructor
166 Klass();
167
168 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
169
170 public:
171 enum DefaultsLookupMode { find_defaults, skip_defaults };
172 enum OverpassLookupMode { find_overpass, skip_overpass };
173 enum StaticLookupMode { find_static, skip_static };
174 enum PrivateLookupMode { find_private, skip_private };
175
176 bool is_klass() const volatile { return true; }
177
178 // super
179 Klass* super() const { return _super; }
180 void set_super(Klass* k) { _super = k; }
181
182 // initializes _super link, _primary_supers & _secondary_supers arrays
183 void initialize_supers(Klass* k, TRAPS);
184 void initialize_supers_impl1(Klass* k);
185 void initialize_supers_impl2(Klass* k);
186
187 // klass-specific helper for initializing _secondary_supers
188 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
189
190 // java_super is the Java-level super type as specified by Class.getSuperClass.
191 virtual Klass* java_super() const { return NULL; }
192
193 juint super_check_offset() const { return _super_check_offset; }
194 void set_super_check_offset(juint o) { _super_check_offset = o; }
195
196 Klass* secondary_super_cache() const { return _secondary_super_cache; }
197 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
198
199 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
200 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
201
202 // Return the element of the _super chain of the given depth.
203 // If there is no such element, return either NULL or this.
204 Klass* primary_super_of_depth(juint i) const {
205 assert(i < primary_super_limit(), "oob");
206 Klass* super = _primary_supers[i];
207 assert(super == NULL || super->super_depth() == i, "correct display");
208 return super;
209 }
210
211 // Can this klass be a primary super? False for interfaces and arrays of
212 // interfaces. False also for arrays or classes with long super chains.
213 bool can_be_primary_super() const {
214 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
215 return super_check_offset() != secondary_offset;
216 }
217 virtual bool can_be_primary_super_slow() const;
218
219 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
220 juint super_depth() const {
221 if (!can_be_primary_super()) {
222 return primary_super_limit();
223 } else {
224 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
225 assert(d < primary_super_limit(), "oob");
226 assert(_primary_supers[d] == this, "proper init");
227 return d;
228 }
229 }
230
231 // store an oop into a field of a Klass
232 void klass_oop_store(oop* p, oop v);
233 void klass_oop_store(volatile oop* p, oop v);
234
235 // java mirror
236 oop java_mirror() const { return _java_mirror; }
237 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); }
238
239 // modifier flags
240 jint modifier_flags() const { return _modifier_flags; }
241 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
242
243 // size helper
244 int layout_helper() const { return _layout_helper; }
245 void set_layout_helper(int lh) { _layout_helper = lh; }
246
247 // Note: for instances layout_helper() may include padding.
248 // Use InstanceKlass::contains_field_offset to classify field offsets.
249
250 // sub/superklass links
251 Klass* subklass() const { return _subklass; }
252 Klass* next_sibling() const { return _next_sibling; }
253 InstanceKlass* superklass() const;
254 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
255
256 void set_next_link(Klass* k) { _next_link = k; }
257 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
258
259 // class loader data
260 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
261 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
262
263 // The Klasses are not placed in the Heap, so the Card Table or
264 // the Mod Union Table can't be used to mark when klasses have modified oops.
265 // The CT and MUT bits saves this information for the individual Klasses.
266 void record_modified_oops() { _modified_oops = 1; }
267 void clear_modified_oops() { _modified_oops = 0; }
268 bool has_modified_oops() { return _modified_oops == 1; }
269
270 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; }
271 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; }
272 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; }
273
274 int shared_classpath_index() const {
275 return _shared_class_path_index;
276 };
277
278 void set_shared_classpath_index(int index) {
279 _shared_class_path_index = index;
280 };
281
282 // Obtain the module or package for this class
283 virtual ModuleEntry* module() const = 0;
284 virtual PackageEntry* package() const = 0;
285
286 protected: // internal accessors
287 void set_subklass(Klass* s);
288 void set_next_sibling(Klass* s);
289
290 public:
291
292 // Compiler support
293 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
294 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
295 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
296 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
297 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
298 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
299 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
300 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
301 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
302
303 // Unpacking layout_helper:
304 enum {
305 _lh_neutral_value = 0, // neutral non-array non-instance value
306 _lh_instance_slow_path_bit = 0x01,
307 _lh_log2_element_size_shift = BitsPerByte*0,
308 _lh_log2_element_size_mask = BitsPerLong-1,
309 _lh_element_type_shift = BitsPerByte*1,
310 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
311 _lh_header_size_shift = BitsPerByte*2,
312 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
313 _lh_array_tag_bits = 2,
314 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
315 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
316 };
317
318 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
319
320 static int layout_helper_size_in_bytes(jint lh) {
321 assert(lh > (jint)_lh_neutral_value, "must be instance");
322 return (int) lh & ~_lh_instance_slow_path_bit;
323 }
324 static bool layout_helper_needs_slow_path(jint lh) {
325 assert(lh > (jint)_lh_neutral_value, "must be instance");
326 return (lh & _lh_instance_slow_path_bit) != 0;
327 }
328 static bool layout_helper_is_instance(jint lh) {
329 return (jint)lh > (jint)_lh_neutral_value;
330 }
331 static bool layout_helper_is_array(jint lh) {
332 return (jint)lh < (jint)_lh_neutral_value;
333 }
334 static bool layout_helper_is_typeArray(jint lh) {
335 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
336 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
337 }
338 static bool layout_helper_is_objArray(jint lh) {
339 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
340 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
341 }
342 static int layout_helper_header_size(jint lh) {
343 assert(lh < (jint)_lh_neutral_value, "must be array");
344 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
345 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
346 return hsize;
347 }
348 static BasicType layout_helper_element_type(jint lh) {
349 assert(lh < (jint)_lh_neutral_value, "must be array");
350 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
351 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
352 return (BasicType) btvalue;
353 }
354
355 // Want a pattern to quickly diff against layout header in register
356 // find something less clever!
357 static int layout_helper_boolean_diffbit() {
358 jint zlh = array_layout_helper(T_BOOLEAN);
359 jint blh = array_layout_helper(T_BYTE);
360 assert(zlh != blh, "array layout helpers must differ");
361 int diffbit = 1;
362 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
363 diffbit <<= 1;
364 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
365 }
366 return diffbit;
367 }
368
369 static int layout_helper_log2_element_size(jint lh) {
370 assert(lh < (jint)_lh_neutral_value, "must be array");
371 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
372 assert(l2esz <= LogBytesPerLong,
373 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
374 return l2esz;
375 }
376 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
377 return (tag << _lh_array_tag_shift)
378 | (hsize << _lh_header_size_shift)
379 | ((int)etype << _lh_element_type_shift)
380 | (log2_esize << _lh_log2_element_size_shift);
381 }
382 static jint instance_layout_helper(jint size, bool slow_path_flag) {
383 return (size << LogBytesPerWord)
384 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
385 }
386 static int layout_helper_to_size_helper(jint lh) {
387 assert(lh > (jint)_lh_neutral_value, "must be instance");
388 // Note that the following expression discards _lh_instance_slow_path_bit.
389 return lh >> LogBytesPerWord;
390 }
391 // Out-of-line version computes everything based on the etype:
392 static jint array_layout_helper(BasicType etype);
393
394 // What is the maximum number of primary superclasses any klass can have?
395 #ifdef PRODUCT
396 static juint primary_super_limit() { return _primary_super_limit; }
397 #else
398 static juint primary_super_limit() {
399 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
400 return FastSuperclassLimit;
401 }
402 #endif
403
404 // vtables
405 klassVtable vtable() const;
406 int vtable_length() const { return _vtable_len; }
407
408 // subclass check
409 bool is_subclass_of(const Klass* k) const;
410 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
411 bool is_subtype_of(Klass* k) const {
412 juint off = k->super_check_offset();
413 Klass* sup = *(Klass**)( (address)this + off );
414 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
415 if (sup == k) {
416 return true;
417 } else if (off != secondary_offset) {
418 return false;
419 } else {
420 return search_secondary_supers(k);
421 }
422 }
423 bool search_secondary_supers(Klass* k) const;
424
425 // Find LCA in class hierarchy
426 Klass *LCA( Klass *k );
427
428 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
429 // if not, throw either an Error or an Exception.
430 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
431
432 // array copying
433 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
434
435 // tells if the class should be initialized
436 virtual bool should_be_initialized() const { return false; }
437 // initializes the klass
438 virtual void initialize(TRAPS);
439 // lookup operation for MethodLookupCache
440 friend class MethodLookupCache;
441 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const;
442 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const;
443 public:
444 Method* lookup_method(const Symbol* name, const Symbol* signature) const {
445 return uncached_lookup_method(name, signature, find_overpass);
446 }
447
448 // array class with specific rank
449 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
450
451 // array class with this klass as element type
452 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
453
454 // These will return NULL instead of allocating on the heap:
455 // NB: these can block for a mutex, like other functions with TRAPS arg.
456 Klass* array_klass_or_null(int rank);
457 Klass* array_klass_or_null();
458
459 virtual oop protection_domain() const = 0;
460
461 oop class_loader() const;
462
463 virtual oop klass_holder() const { return class_loader(); }
464
465 protected:
466 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
467 virtual Klass* array_klass_impl(bool or_null, TRAPS);
468
469 void set_vtable_length(int len) { _vtable_len= len; }
470
471 vtableEntry* start_of_vtable() const;
472 public:
473 Method* method_at_vtable(int index);
474
475 static ByteSize vtable_start_offset();
476 static ByteSize vtable_length_offset() {
477 return byte_offset_of(Klass, _vtable_len);
478 }
479
480 // CDS support - remove and restore oops from metadata. Oops are not shared.
481 virtual void remove_unshareable_info();
482 virtual void remove_java_mirror();
483 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
484
485 protected:
486 // computes the subtype relationship
487 virtual bool compute_is_subtype_of(Klass* k);
488 public:
489 // subclass accessor (here for convenience; undefined for non-klass objects)
490 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
491 public:
492 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
493 // These functions describe behavior for the oop not the KLASS.
494
495 // actual oop size of obj in memory
496 virtual int oop_size(oop obj) const = 0;
497
498 // Size of klass in word size.
499 virtual int size() const = 0;
500 #if INCLUDE_SERVICES
501 virtual void collect_statistics(KlassSizeStats *sz) const;
502 #endif
503
504 // Returns the Java name for a class (Resource allocated)
505 // For arrays, this returns the name of the element with a leading '['.
506 // For classes, this returns the name with the package separators
507 // turned into '.'s.
508 const char* external_name() const;
509 // Returns the name for a class (Resource allocated) as the class
510 // would appear in a signature.
511 // For arrays, this returns the name of the element with a leading '['.
512 // For classes, this returns the name with a leading 'L' and a trailing ';'
513 // and the package separators as '/'.
514 virtual const char* signature_name() const;
515
516 // type testing operations
517 #ifdef ASSERT
518 protected:
519 virtual bool is_instance_klass_slow() const { return false; }
520 virtual bool is_array_klass_slow() const { return false; }
521 virtual bool is_objArray_klass_slow() const { return false; }
522 virtual bool is_typeArray_klass_slow() const { return false; }
523 #endif // ASSERT
524 public:
525
526 // Fast non-virtual versions
527 #ifndef ASSERT
528 #define assert_same_query(xval, xcheck) xval
529 #else
530 private:
531 static bool assert_same_query(bool xval, bool xslow) {
532 assert(xval == xslow, "slow and fast queries agree");
533 return xval;
534 }
535 public:
536 #endif
537 inline bool is_instance_klass() const { return assert_same_query(
538 layout_helper_is_instance(layout_helper()),
539 is_instance_klass_slow()); }
540 inline bool is_array_klass() const { return assert_same_query(
541 layout_helper_is_array(layout_helper()),
542 is_array_klass_slow()); }
543 inline bool is_objArray_klass() const { return assert_same_query(
544 layout_helper_is_objArray(layout_helper()),
545 is_objArray_klass_slow()); }
546 inline bool is_typeArray_klass() const { return assert_same_query(
547 layout_helper_is_typeArray(layout_helper()),
548 is_typeArray_klass_slow()); }
549 #undef assert_same_query
550
551 // Access flags
552 AccessFlags access_flags() const { return _access_flags; }
553 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
554
555 bool is_public() const { return _access_flags.is_public(); }
556 bool is_final() const { return _access_flags.is_final(); }
557 bool is_interface() const { return _access_flags.is_interface(); }
558 bool is_abstract() const { return _access_flags.is_abstract(); }
559 bool is_super() const { return _access_flags.is_super(); }
560 bool is_synthetic() const { return _access_flags.is_synthetic(); }
561 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
562 bool has_finalizer() const { return _access_flags.has_finalizer(); }
563 bool has_final_method() const { return _access_flags.has_final_method(); }
564 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
565 void set_has_final_method() { _access_flags.set_has_final_method(); }
566 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
567 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
568 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
569 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
570 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
571 void set_is_shared() { _access_flags.set_is_shared_class(); }
572
573 bool is_cloneable() const;
574 void set_is_cloneable();
575
576 // Biased locking support
577 // Note: the prototype header is always set up to be at least the
578 // prototype markOop. If biased locking is enabled it may further be
579 // biasable and have an epoch.
580 markOop prototype_header() const { return _prototype_header; }
581 // NOTE: once instances of this klass are floating around in the
582 // system, this header must only be updated at a safepoint.
583 // NOTE 2: currently we only ever set the prototype header to the
584 // biasable prototype for instanceKlasses. There is no technical
585 // reason why it could not be done for arrayKlasses aside from
586 // wanting to reduce the initial scope of this optimization. There
587 // are potential problems in setting the bias pattern for
588 // JVM-internal oops.
589 inline void set_prototype_header(markOop header);
590 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
591
592 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
593 // Atomically increments biased_lock_revocation_count and returns updated value
594 int atomic_incr_biased_lock_revocation_count();
595 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
596 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
597 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
598
599 TRACE_DEFINE_TRACE_ID_METHODS;
600
601 // garbage collection support
602 void oops_do(OopClosure* cl);
603
604 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
605 virtual MetaspaceObj::Type type() const { return ClassType; }
606
607 // Iff the class loader (or mirror for anonymous classes) is alive the
608 // Klass is considered alive.
609 // The is_alive closure passed in depends on the Garbage Collector used.
610 bool is_loader_alive(BoolObjectClosure* is_alive);
611
612 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true);
613 static void clean_subklass_tree(BoolObjectClosure* is_alive) {
614 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */);
615 }
616
617 // GC specific object visitors
618 //
619 #if INCLUDE_ALL_GCS
620 // Parallel Scavenge
621 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0;
622 // Parallel Compact
623 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0;
624 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0;
625 #endif
626
627 // Iterators specialized to particular subtypes
628 // of ExtendedOopClosure, to avoid closure virtual calls.
629 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
630 virtual void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) = 0; \
631 /* Iterates "closure" over all the oops in "obj" (of type "this") within "mr". */ \
632 virtual void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) = 0;
633
634 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
635 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
636
637 #if INCLUDE_ALL_GCS
638 #define Klass_OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
639 virtual void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) = 0;
640
641 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
642 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS)
643 #endif // INCLUDE_ALL_GCS
644
645 virtual void array_klasses_do(void f(Klass* k)) {}
646
647 // Return self, except for abstract classes with exactly 1
648 // implementor. Then return the 1 concrete implementation.
649 Klass *up_cast_abstract();
650
651 // klass name
652 Symbol* name() const { return _name; }
653 void set_name(Symbol* n);
654
655 public:
656 // jvm support
657 virtual jint compute_modifier_flags(TRAPS) const;
658
659 // JVMTI support
660 virtual jint jvmti_class_status() const;
661
662 // Printing
663 virtual void print_on(outputStream* st) const;
664
665 virtual void oop_print_value_on(oop obj, outputStream* st);
666 virtual void oop_print_on (oop obj, outputStream* st);
667
668 virtual const char* internal_name() const = 0;
669
670 // Verification
671 virtual void verify_on(outputStream* st);
672 void verify() { verify_on(tty); }
673
674 #ifndef PRODUCT
675 bool verify_vtable_index(int index);
676 bool verify_itable_index(int index);
677 #endif
678
679 virtual void oop_verify_on(oop obj, outputStream* st);
680
681 static bool is_null(narrowKlass obj);
682 static bool is_null(Klass* obj);
683
684 // klass encoding for klass pointer in objects.
685 static narrowKlass encode_klass_not_null(Klass* v);
686 static narrowKlass encode_klass(Klass* v);
687
688 static Klass* decode_klass_not_null(narrowKlass v);
689 static Klass* decode_klass(narrowKlass v);
690
691 private:
692 // barriers used by klass_oop_store
693 void klass_update_barrier_set(oop v);
694 void klass_update_barrier_set_pre(oop* p, oop v);
695 };
696
697 // Helper to convert the oop iterate macro suffixes into bool values that can be used by template functions.
698 #define nvs_nv_to_bool true
699 #define nvs_v_to_bool false
700 #define nvs_to_bool(nv_suffix) nvs##nv_suffix##_to_bool
701
702 // Oop iteration macros for declarations.
703 // Used to generate declarations in the *Klass header files.
704
705 #define OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
706 void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure); \
707 void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr);
708
709 #if INCLUDE_ALL_GCS
710 #define OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \
711 void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure);
712 #endif // INCLUDE_ALL_GCS
713
714
715 // Oop iteration macros for definitions.
716 // Used to generate definitions in the *Klass.inline.hpp files.
717
718 #define OOP_OOP_ITERATE_DEFN(KlassType, OopClosureType, nv_suffix) \
719 void KlassType::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
720 oop_oop_iterate<nvs_to_bool(nv_suffix)>(obj, closure); \
721 }
722
723 #if INCLUDE_ALL_GCS
724 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) \
725 void KlassType::oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \
726 oop_oop_iterate_reverse<nvs_to_bool(nv_suffix)>(obj, closure); \
727 }
728 #else
729 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix)
730 #endif
731
732 #define OOP_OOP_ITERATE_DEFN_BOUNDED(KlassType, OopClosureType, nv_suffix) \
733 void KlassType::oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) { \
734 oop_oop_iterate_bounded<nvs_to_bool(nv_suffix)>(obj, closure, mr); \
735 }
736
737 #endif // SHARE_VM_OOPS_KLASS_HPP