1 /*
2 * Copyright (c) 1997, 2011, 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
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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
27
28 #include "memory/genOopClosures.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "memory/specialized_oop_closures.hpp"
32 #include "oops/klassOop.hpp"
33 #include "oops/klassPS.hpp"
34 #include "oops/oop.hpp"
35 #include "runtime/orderAccess.hpp"
36 #include "utilities/accessFlags.hpp"
37 #ifndef SERIALGC
38 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp"
39 #include "gc_implementation/g1/g1OopClosures.hpp"
40 #include "gc_implementation/parNew/parOopClosures.hpp"
41 #endif
42
43 // A Klass is the part of the klassOop that provides:
44 // 1: language level class object (method dictionary etc.)
45 // 2: provide vm dispatch behavior for the object
46 // Both functions are combined into one C++ class. The toplevel class "Klass"
47 // implements purpose 1 whereas all subclasses provide extra virtual functions
48 // for purpose 2.
49
50 // One reason for the oop/klass dichotomy in the implementation is
51 // that we don't want a C++ vtbl pointer in every object. Thus,
52 // normal oops don't have any virtual functions. Instead, they
53 // forward all "virtual" functions to their klass, which does have
54 // a vtbl and does the C++ dispatch depending on the object's
55 // actual type. (See oop.inline.hpp for some of the forwarding code.)
56 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
57
58 // Klass layout:
59 // [header ] klassOop
60 // [klass pointer ] klassOop
61 // [C++ vtbl ptr ] (contained in Klass_vtbl)
62 // [layout_helper ]
63 // [super_check_offset ] for fast subtype checks
64 // [secondary_super_cache] for fast subtype checks
65 // [secondary_supers ] array of 2ndary supertypes
66 // [primary_supers 0]
67 // [primary_supers 1]
68 // [primary_supers 2]
69 // ...
70 // [primary_supers 7]
71 // [java_mirror ]
72 // [super ]
73 // [name ]
74 // [first subklass]
75 // [next_sibling ] link to chain additional subklasses
76 // [modifier_flags]
77 // [access_flags ]
78 // [verify_count ] - not in product
79 // [alloc_count ]
80 // [last_biased_lock_bulk_revocation_time] (64 bits)
81 // [prototype_header]
82 // [biased_lock_revocation_count]
83
84
85 // Forward declarations.
86 class klassVtable;
87 class KlassHandle;
88 class OrderAccess;
89
90 // Holder (or cage) for the C++ vtable of each kind of Klass.
91 // We want to tightly constrain the location of the C++ vtable in the overall layout.
92 class Klass_vtbl {
93 protected:
94 // The following virtual exists only to force creation of a C++ vtable,
95 // so that this class truly is the location of the vtable of all Klasses.
96 virtual void unused_initial_virtual() { }
97
98 public:
99 // The following virtual makes Klass_vtbl play a second role as a
100 // factory protocol for subclasses of Klass ("sub-Klasses").
101 // Here's how it works....
102 //
103 // This VM uses metaobjects as factories for their instances.
104 //
105 // In order to initialize the C++ vtable of a new instance, its
106 // metaobject is forced to use the C++ placed new operator to
107 // allocate the instance. In a typical C++-based system, each
108 // sub-class would have its own factory routine which
109 // directly uses the placed new operator on the desired class,
110 // and then calls the appropriate chain of C++ constructors.
111 //
112 // However, this system uses shared code to performs the first
113 // allocation and initialization steps for all sub-Klasses.
114 // (See base_create_klass() and base_create_array_klass().)
115 // This does not factor neatly into a hierarchy of C++ constructors.
116 // Each caller of these shared "base_create" routines knows
117 // exactly which sub-Klass it is creating, but the shared routine
118 // does not, even though it must perform the actual allocation.
119 //
120 // Therefore, the caller of the shared "base_create" must wrap
121 // the specific placed new call in a virtual function which
122 // performs the actual allocation and vtable set-up. That
123 // virtual function is here, Klass_vtbl::allocate_permanent.
124 //
125 // The arguments to Universe::allocate_permanent() are passed
126 // straight through the placed new operator, which in turn
127 // obtains them directly from this virtual call.
128 //
129 // This virtual is called on a temporary "example instance" of the
130 // sub-Klass being instantiated, a C++ auto variable. The "real"
131 // instance created by this virtual is on the VM heap, where it is
132 // equipped with a klassOopDesc header.
133 //
134 // It is merely an accident of implementation that we use "example
135 // instances", but that is why the virtual function which implements
136 // each sub-Klass factory happens to be defined by the same sub-Klass
137 // for which it creates instances.
138 //
139 // The vtbl_value() call (see below) is used to strip away the
140 // accidental Klass-ness from an "example instance" and present it as
141 // a factory. Think of each factory object as a mere container of the
142 // C++ vtable for the desired sub-Klass. Since C++ does not allow
143 // direct references to vtables, the factory must also be delegated
144 // the task of allocating the instance, but the essential point is
145 // that the factory knows how to initialize the C++ vtable with the
146 // right pointer value. All other common initializations are handled
147 // by the shared "base_create" subroutines.
148 //
149 virtual void* allocate_permanent(KlassHandle& klass, int size, TRAPS) const = 0;
150 void post_new_init_klass(KlassHandle& klass, klassOop obj, int size) const;
151
152 // Every subclass on which vtbl_value is called must include this macro.
153 // Delay the installation of the klassKlass pointer until after the
154 // the vtable for a new klass has been installed (after the call to new()).
155 #define DEFINE_ALLOCATE_PERMANENT(thisKlass) \
156 void* allocate_permanent(KlassHandle& klass_klass, int size, TRAPS) const { \
157 void* result = new(klass_klass, size, THREAD) thisKlass(); \
158 if (HAS_PENDING_EXCEPTION) return NULL; \
159 klassOop new_klass = ((Klass*) result)->as_klassOop(); \
160 OrderAccess::storestore(); \
161 post_new_init_klass(klass_klass, new_klass, size); \
162 return result; \
163 }
164
165 bool null_vtbl() { return *(intptr_t*)this == 0; }
166
167 protected:
168 void* operator new(size_t ignored, KlassHandle& klass, int size, TRAPS);
169 };
170
171
172 class Klass : public Klass_vtbl {
173 friend class VMStructs;
174 protected:
175 // note: put frequently-used fields together at start of klass structure
176 // for better cache behavior (may not make much of a difference but sure won't hurt)
177 enum { _primary_super_limit = 8 };
178
179 // The "layout helper" is a combined descriptor of object layout.
180 // For klasses which are neither instance nor array, the value is zero.
181 //
182 // For instances, layout helper is a positive number, the instance size.
183 // This size is already passed through align_object_size and scaled to bytes.
184 // The low order bit is set if instances of this class cannot be
185 // allocated using the fastpath.
186 //
187 // For arrays, layout helper is a negative number, containing four
188 // distinct bytes, as follows:
189 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
190 // where:
191 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
192 // hsz is array header size in bytes (i.e., offset of first element)
193 // ebt is the BasicType of the elements
194 // esz is the element size in bytes
195 // This packed word is arranged so as to be quickly unpacked by the
196 // various fast paths that use the various subfields.
197 //
198 // The esz bits can be used directly by a SLL instruction, without masking.
199 //
200 // Note that the array-kind tag looks like 0x00 for instance klasses,
201 // since their length in bytes is always less than 24Mb.
202 //
203 // Final note: This comes first, immediately after Klass_vtbl,
204 // because it is frequently queried.
205 jint _layout_helper;
206
207 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
208 // and _primary_supers all help make fast subtype checks. See big discussion
209 // in doc/server_compiler/checktype.txt
210 //
211 // Where to look to observe a supertype (it is &_secondary_super_cache for
212 // secondary supers, else is &_primary_supers[depth()].
213 juint _super_check_offset;
214
215 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
216 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
217 Symbol* _name;
218
219 public:
220 oop* oop_block_beg() const { return adr_secondary_super_cache(); }
221 oop* oop_block_end() const { return adr_next_sibling() + 1; }
222
223 protected:
224 //
225 // The oop block. All oop fields must be declared here and only oop fields
226 // may be declared here. In addition, the first and last fields in this block
227 // must remain first and last, unless oop_block_beg() and/or oop_block_end()
228 // are updated. Grouping the oop fields in a single block simplifies oop
229 // iteration.
230 //
231
232 // Cache of last observed secondary supertype
233 klassOop _secondary_super_cache;
234 // Array of all secondary supertypes
235 objArrayOop _secondary_supers;
236 // Ordered list of all primary supertypes
237 klassOop _primary_supers[_primary_super_limit];
238 // java/lang/Class instance mirroring this class
239 oop _java_mirror;
240 // Superclass
241 klassOop _super;
242 // First subclass (NULL if none); _subklass->next_sibling() is next one
243 klassOop _subklass;
244 // Sibling link (or NULL); links all subklasses of a klass
245 klassOop _next_sibling;
246
247 //
248 // End of the oop block.
249 //
250
251 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
252 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
253
254 #ifndef PRODUCT
255 int _verify_count; // to avoid redundant verifies
256 #endif
257
258 juint _alloc_count; // allocation profiling support - update klass_size_in_bytes() if moved/deleted
259
260 // Biased locking implementation and statistics
261 // (the 64-bit chunk goes first, to avoid some fragmentation)
262 jlong _last_biased_lock_bulk_revocation_time;
263 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
264 jint _biased_lock_revocation_count;
265
266 public:
267
268 // returns the enclosing klassOop
269 klassOop as_klassOop() const {
270 // see klassOop.hpp for layout.
271 return (klassOop) (((char*) this) - sizeof(klassOopDesc));
272 }
273
274 public:
275 // Allocation
276 const Klass_vtbl& vtbl_value() const { return *this; } // used only on "example instances"
277 static KlassHandle base_create_klass(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
278 static klassOop base_create_klass_oop(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
279
280 // super
281 klassOop super() const { return _super; }
282 void set_super(klassOop k) { oop_store_without_check((oop*) &_super, (oop) k); }
283
284 // initializes _super link, _primary_supers & _secondary_supers arrays
285 void initialize_supers(klassOop k, TRAPS);
286 void initialize_supers_impl1(klassOop k);
287 void initialize_supers_impl2(klassOop k);
288
289 // klass-specific helper for initializing _secondary_supers
290 virtual objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS);
291
292 // java_super is the Java-level super type as specified by Class.getSuperClass.
293 virtual klassOop java_super() const { return NULL; }
294
295 juint super_check_offset() const { return _super_check_offset; }
296 void set_super_check_offset(juint o) { _super_check_offset = o; }
297
298 klassOop secondary_super_cache() const { return _secondary_super_cache; }
299 void set_secondary_super_cache(klassOop k) { oop_store_without_check((oop*) &_secondary_super_cache, (oop) k); }
300
301 objArrayOop secondary_supers() const { return _secondary_supers; }
302 void set_secondary_supers(objArrayOop k) { oop_store_without_check((oop*) &_secondary_supers, (oop) k); }
303
304 // Return the element of the _super chain of the given depth.
305 // If there is no such element, return either NULL or this.
306 klassOop primary_super_of_depth(juint i) const {
307 assert(i < primary_super_limit(), "oob");
308 klassOop super = _primary_supers[i];
309 assert(super == NULL || super->klass_part()->super_depth() == i, "correct display");
310 return super;
311 }
312
313 // Can this klass be a primary super? False for interfaces and arrays of
314 // interfaces. False also for arrays or classes with long super chains.
315 bool can_be_primary_super() const {
316 const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc);
317 return super_check_offset() != secondary_offset;
318 }
319 virtual bool can_be_primary_super_slow() const;
320
321 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
322 juint super_depth() const {
323 if (!can_be_primary_super()) {
324 return primary_super_limit();
325 } else {
326 juint d = (super_check_offset() - (primary_supers_offset_in_bytes() + sizeof(oopDesc))) / sizeof(klassOop);
327 assert(d < primary_super_limit(), "oob");
328 assert(_primary_supers[d] == as_klassOop(), "proper init");
329 return d;
330 }
331 }
332
333 // java mirror
334 oop java_mirror() const { return _java_mirror; }
335 void set_java_mirror(oop m) { oop_store((oop*) &_java_mirror, m); }
336
337 // modifier flags
338 jint modifier_flags() const { return _modifier_flags; }
339 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
340
341 // size helper
342 int layout_helper() const { return _layout_helper; }
343 void set_layout_helper(int lh) { _layout_helper = lh; }
344
345 // Note: for instances layout_helper() may include padding.
346 // Use instanceKlass::contains_field_offset to classify field offsets.
347
348 // sub/superklass links
349 instanceKlass* superklass() const;
350 Klass* subklass() const;
351 Klass* next_sibling() const;
352 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
353 void remove_from_sibling_list(); // remove receiver from sibling list
354 protected: // internal accessors
355 klassOop subklass_oop() const { return _subklass; }
356 klassOop next_sibling_oop() const { return _next_sibling; }
357 void set_subklass(klassOop s);
358 void set_next_sibling(klassOop s);
359
360 oop* adr_super() const { return (oop*)&_super; }
361 oop* adr_primary_supers() const { return (oop*)&_primary_supers[0]; }
362 oop* adr_secondary_super_cache() const { return (oop*)&_secondary_super_cache; }
363 oop* adr_secondary_supers()const { return (oop*)&_secondary_supers; }
364 oop* adr_java_mirror() const { return (oop*)&_java_mirror; }
365 oop* adr_subklass() const { return (oop*)&_subklass; }
366 oop* adr_next_sibling() const { return (oop*)&_next_sibling; }
367
368 public:
369 // Allocation profiling support
370 juint alloc_count() const { return _alloc_count; }
371 void set_alloc_count(juint n) { _alloc_count = n; }
372 virtual juint alloc_size() const = 0;
373 virtual void set_alloc_size(juint n) = 0;
374
375 // Compiler support
376 static int super_offset_in_bytes() { return offset_of(Klass, _super); }
377 static int super_check_offset_offset_in_bytes() { return offset_of(Klass, _super_check_offset); }
378 static int primary_supers_offset_in_bytes(){ return offset_of(Klass, _primary_supers); }
379 static int secondary_super_cache_offset_in_bytes() { return offset_of(Klass, _secondary_super_cache); }
380 static int secondary_supers_offset_in_bytes() { return offset_of(Klass, _secondary_supers); }
381 static int java_mirror_offset_in_bytes() { return offset_of(Klass, _java_mirror); }
382 static int modifier_flags_offset_in_bytes(){ return offset_of(Klass, _modifier_flags); }
383 static int layout_helper_offset_in_bytes() { return offset_of(Klass, _layout_helper); }
384 static int access_flags_offset_in_bytes() { return offset_of(Klass, _access_flags); }
385
386 // Unpacking layout_helper:
387 enum {
388 _lh_neutral_value = 0, // neutral non-array non-instance value
389 _lh_instance_slow_path_bit = 0x01,
390 _lh_log2_element_size_shift = BitsPerByte*0,
391 _lh_log2_element_size_mask = BitsPerLong-1,
392 _lh_element_type_shift = BitsPerByte*1,
393 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
394 _lh_header_size_shift = BitsPerByte*2,
395 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
396 _lh_array_tag_bits = 2,
397 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
398 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
399 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
400 };
401
402 static int layout_helper_size_in_bytes(jint lh) {
403 assert(lh > (jint)_lh_neutral_value, "must be instance");
404 return (int) lh & ~_lh_instance_slow_path_bit;
405 }
406 static bool layout_helper_needs_slow_path(jint lh) {
407 assert(lh > (jint)_lh_neutral_value, "must be instance");
408 return (lh & _lh_instance_slow_path_bit) != 0;
409 }
410 static bool layout_helper_is_instance(jint lh) {
411 return (jint)lh > (jint)_lh_neutral_value;
412 }
413 static bool layout_helper_is_javaArray(jint lh) {
414 return (jint)lh < (jint)_lh_neutral_value;
415 }
416 static bool layout_helper_is_typeArray(jint lh) {
417 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
418 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
419 }
420 static bool layout_helper_is_objArray(jint lh) {
421 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
422 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
423 }
424 static int layout_helper_header_size(jint lh) {
425 assert(lh < (jint)_lh_neutral_value, "must be array");
426 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
427 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
428 return hsize;
429 }
430 static BasicType layout_helper_element_type(jint lh) {
431 assert(lh < (jint)_lh_neutral_value, "must be array");
432 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
433 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
434 return (BasicType) btvalue;
435 }
436 static int layout_helper_log2_element_size(jint lh) {
437 assert(lh < (jint)_lh_neutral_value, "must be array");
438 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
439 assert(l2esz <= LogBitsPerLong, "sanity");
440 return l2esz;
441 }
442 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
443 return (tag << _lh_array_tag_shift)
444 | (hsize << _lh_header_size_shift)
445 | ((int)etype << _lh_element_type_shift)
446 | (log2_esize << _lh_log2_element_size_shift);
447 }
448 static jint instance_layout_helper(jint size, bool slow_path_flag) {
449 return (size << LogHeapWordSize)
450 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
451 }
452 static int layout_helper_to_size_helper(jint lh) {
453 assert(lh > (jint)_lh_neutral_value, "must be instance");
454 // Note that the following expression discards _lh_instance_slow_path_bit.
455 return lh >> LogHeapWordSize;
456 }
457 // Out-of-line version computes everything based on the etype:
458 static jint array_layout_helper(BasicType etype);
459
460 // What is the maximum number of primary superclasses any klass can have?
461 #ifdef PRODUCT
462 static juint primary_super_limit() { return _primary_super_limit; }
463 #else
464 static juint primary_super_limit() {
465 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
466 return FastSuperclassLimit;
467 }
468 #endif
469
470 // vtables
471 virtual klassVtable* vtable() const { return NULL; }
472
473 static int klass_size_in_bytes() { return offset_of(Klass, _alloc_count) + sizeof(juint); } // all "visible" fields
474
475 // subclass check
476 bool is_subclass_of(klassOop k) const;
477 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
478 bool is_subtype_of(klassOop k) const {
479 juint off = k->klass_part()->super_check_offset();
480 klassOop sup = *(klassOop*)( (address)as_klassOop() + off );
481 const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc);
482 if (sup == k) {
483 return true;
484 } else if (off != secondary_offset) {
485 return false;
486 } else {
487 return search_secondary_supers(k);
488 }
489 }
490 bool search_secondary_supers(klassOop k) const;
491
492 // Find LCA in class hierarchy
493 Klass *LCA( Klass *k );
494
495 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
496 // if not, throw either an Error or an Exception.
497 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
498
499 // Casting
500 static Klass* cast(klassOop k) {
501 assert(k->is_klass(), "cast to Klass");
502 return k->klass_part();
503 }
504
505 // array copying
506 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
507
508 // tells if the class should be initialized
509 virtual bool should_be_initialized() const { return false; }
510 // initializes the klass
511 virtual void initialize(TRAPS);
512 // lookup operation for MethodLookupCache
513 friend class MethodLookupCache;
514 virtual methodOop uncached_lookup_method(Symbol* name, Symbol* signature) const;
515 public:
516 methodOop lookup_method(Symbol* name, Symbol* signature) const {
517 return uncached_lookup_method(name, signature);
518 }
519
520 // array class with specific rank
521 klassOop array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
522
523 // array class with this klass as element type
524 klassOop array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
525
526 // These will return NULL instead of allocating on the heap:
527 // NB: these can block for a mutex, like other functions with TRAPS arg.
528 klassOop array_klass_or_null(int rank);
529 klassOop array_klass_or_null();
530
531 virtual oop protection_domain() { return NULL; }
532 virtual oop class_loader() const { return NULL; }
533
534 protected:
535 virtual klassOop array_klass_impl(bool or_null, int rank, TRAPS);
536 virtual klassOop array_klass_impl(bool or_null, TRAPS);
537
538 public:
539 virtual void remove_unshareable_info();
540 virtual void shared_symbols_iterate(SymbolClosure* closure);
541
542 protected:
543 // computes the subtype relationship
544 virtual bool compute_is_subtype_of(klassOop k);
545 public:
546 // subclass accessor (here for convenience; undefined for non-klass objects)
547 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
548 public:
549 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
550 // These functions describe behavior for the oop not the KLASS.
551
552 // actual oop size of obj in memory
553 virtual int oop_size(oop obj) const = 0;
554
555 // actual oop size of this klass in memory
556 virtual int klass_oop_size() const = 0;
557
558 // Returns the Java name for a class (Resource allocated)
559 // For arrays, this returns the name of the element with a leading '['.
560 // For classes, this returns the name with the package separators
561 // turned into '.'s.
562 const char* external_name() const;
563 // Returns the name for a class (Resource allocated) as the class
564 // would appear in a signature.
565 // For arrays, this returns the name of the element with a leading '['.
566 // For classes, this returns the name with a leading 'L' and a trailing ';'
567 // and the package separators as '/'.
568 virtual const char* signature_name() const;
569
570 // garbage collection support
571 virtual void oop_follow_contents(oop obj) = 0;
572 virtual int oop_adjust_pointers(oop obj) = 0;
573
574 // Parallel Scavenge and Parallel Old
575 PARALLEL_GC_DECLS_PV
576
577 public:
578 // type testing operations
579 virtual bool oop_is_instance_slow() const { return false; }
580 virtual bool oop_is_instanceMirror() const { return false; }
581 virtual bool oop_is_instanceRef() const { return false; }
582 virtual bool oop_is_array() const { return false; }
583 virtual bool oop_is_objArray_slow() const { return false; }
584 virtual bool oop_is_klass() const { return false; }
585 virtual bool oop_is_thread() const { return false; }
586 virtual bool oop_is_method() const { return false; }
587 virtual bool oop_is_constMethod() const { return false; }
588 virtual bool oop_is_methodData() const { return false; }
589 virtual bool oop_is_constantPool() const { return false; }
590 virtual bool oop_is_constantPoolCache() const { return false; }
591 virtual bool oop_is_typeArray_slow() const { return false; }
592 virtual bool oop_is_arrayKlass() const { return false; }
593 virtual bool oop_is_objArrayKlass() const { return false; }
594 virtual bool oop_is_typeArrayKlass() const { return false; }
595 virtual bool oop_is_compiledICHolder() const { return false; }
596 virtual bool oop_is_instanceKlass() const { return false; }
597
598 bool oop_is_javaArray_slow() const {
599 return oop_is_objArray_slow() || oop_is_typeArray_slow();
600 }
601
602 // Fast non-virtual versions, used by oop.inline.hpp and elsewhere:
603 #ifndef ASSERT
604 #define assert_same_query(xval, xcheck) xval
605 #else
606 private:
607 static bool assert_same_query(bool xval, bool xslow) {
608 assert(xval == xslow, "slow and fast queries agree");
609 return xval;
610 }
611 public:
612 #endif
613 inline bool oop_is_instance() const { return assert_same_query(
614 layout_helper_is_instance(layout_helper()),
615 oop_is_instance_slow()); }
616 inline bool oop_is_javaArray() const { return assert_same_query(
617 layout_helper_is_javaArray(layout_helper()),
618 oop_is_javaArray_slow()); }
619 inline bool oop_is_objArray() const { return assert_same_query(
620 layout_helper_is_objArray(layout_helper()),
621 oop_is_objArray_slow()); }
622 inline bool oop_is_typeArray() const { return assert_same_query(
623 layout_helper_is_typeArray(layout_helper()),
624 oop_is_typeArray_slow()); }
625 #undef assert_same_query
626
627 // Unless overridden, oop is parsable if it has a klass pointer.
628 // Parsability of an object is object specific.
629 virtual bool oop_is_parsable(oop obj) const { return true; }
630
631 // Unless overridden, oop is safe for concurrent GC processing
632 // after its allocation is complete. The exception to
633 // this is the case where objects are changed after allocation.
634 // Class redefinition is one of the known exceptions. During
635 // class redefinition, an allocated class can changed in order
636 // order to create a merged class (the combiniation of the
637 // old class definition that has to be perserved and the new class
638 // definition which is being created.
639 virtual bool oop_is_conc_safe(oop obj) const { return true; }
640
641 // Access flags
642 AccessFlags access_flags() const { return _access_flags; }
643 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
644
645 bool is_public() const { return _access_flags.is_public(); }
646 bool is_final() const { return _access_flags.is_final(); }
647 bool is_interface() const { return _access_flags.is_interface(); }
648 bool is_abstract() const { return _access_flags.is_abstract(); }
649 bool is_super() const { return _access_flags.is_super(); }
650 bool is_synthetic() const { return _access_flags.is_synthetic(); }
651 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
652 bool has_finalizer() const { return _access_flags.has_finalizer(); }
653 bool has_final_method() const { return _access_flags.has_final_method(); }
654 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
655 void set_has_final_method() { _access_flags.set_has_final_method(); }
656 bool is_cloneable() const { return _access_flags.is_cloneable(); }
657 void set_is_cloneable() { _access_flags.set_is_cloneable(); }
658 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
659 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
660 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
661 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
662
663 // Biased locking support
664 // Note: the prototype header is always set up to be at least the
665 // prototype markOop. If biased locking is enabled it may further be
666 // biasable and have an epoch.
667 markOop prototype_header() const { return _prototype_header; }
668 // NOTE: once instances of this klass are floating around in the
669 // system, this header must only be updated at a safepoint.
670 // NOTE 2: currently we only ever set the prototype header to the
671 // biasable prototype for instanceKlasses. There is no technical
672 // reason why it could not be done for arrayKlasses aside from
673 // wanting to reduce the initial scope of this optimization. There
674 // are potential problems in setting the bias pattern for
675 // JVM-internal oops.
676 inline void set_prototype_header(markOop header);
677 static int prototype_header_offset_in_bytes() { return offset_of(Klass, _prototype_header); }
678
679 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
680 // Atomically increments biased_lock_revocation_count and returns updated value
681 int atomic_incr_biased_lock_revocation_count();
682 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
683 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
684 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
685
686
687 // garbage collection support
688 virtual void follow_weak_klass_links(
689 BoolObjectClosure* is_alive, OopClosure* keep_alive);
690
691 // Prefetch within oop iterators. This is a macro because we
692 // can't guarantee that the compiler will inline it. In 64-bit
693 // it generally doesn't. Signature is
694 //
695 // static void prefetch_beyond(oop* const start,
696 // oop* const end,
697 // const intx foffset,
698 // const Prefetch::style pstyle);
699 #define prefetch_beyond(start, end, foffset, pstyle) { \
700 const intx foffset_ = (foffset); \
701 const Prefetch::style pstyle_ = (pstyle); \
702 assert(foffset_ > 0, "prefetch beyond, not behind"); \
703 if (pstyle_ != Prefetch::do_none) { \
704 oop* ref = (start); \
705 if (ref < (end)) { \
706 switch (pstyle_) { \
707 case Prefetch::do_read: \
708 Prefetch::read(*ref, foffset_); \
709 break; \
710 case Prefetch::do_write: \
711 Prefetch::write(*ref, foffset_); \
712 break; \
713 default: \
714 ShouldNotReachHere(); \
715 break; \
716 } \
717 } \
718 } \
719 }
720
721 // iterators
722 virtual int oop_oop_iterate(oop obj, OopClosure* blk) = 0;
723 virtual int oop_oop_iterate_v(oop obj, OopClosure* blk) {
724 return oop_oop_iterate(obj, blk);
725 }
726
727 #ifndef SERIALGC
728 // In case we don't have a specialized backward scanner use forward
729 // iteration.
730 virtual int oop_oop_iterate_backwards_v(oop obj, OopClosure* blk) {
731 return oop_oop_iterate_v(obj, blk);
732 }
733 #endif // !SERIALGC
734
735 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
736 // (I don't see why the _m should be required, but without it the Solaris
737 // C++ gives warning messages about overridings of the "oop_oop_iterate"
738 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */
739 virtual int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) = 0;
740 virtual int oop_oop_iterate_v_m(oop obj, OopClosure* blk, MemRegion mr) {
741 return oop_oop_iterate_m(obj, blk, mr);
742 }
743
744 // Versions of the above iterators specialized to particular subtypes
745 // of OopClosure, to avoid closure virtual calls.
746 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
747 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \
748 /* Default implementation reverts to general version. */ \
749 return oop_oop_iterate(obj, blk); \
750 } \
751 \
752 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
753 (I don't see why the _m should be required, but without it the Solaris \
754 C++ gives warning messages about overridings of the "oop_oop_iterate" \
755 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \
756 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \
757 OopClosureType* blk, \
758 MemRegion mr) { \
759 return oop_oop_iterate_m(obj, blk, mr); \
760 }
761
762 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
763 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
764
765 #ifndef SERIALGC
766 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
767 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \
768 OopClosureType* blk) { \
769 /* Default implementation reverts to general version. */ \
770 return oop_oop_iterate_backwards_v(obj, blk); \
771 }
772
773 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
774 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
775 #endif // !SERIALGC
776
777 virtual void array_klasses_do(void f(klassOop k)) {}
778 virtual void with_array_klasses_do(void f(klassOop k));
779
780 // Return self, except for abstract classes with exactly 1
781 // implementor. Then return the 1 concrete implementation.
782 Klass *up_cast_abstract();
783
784 // klass name
785 Symbol* name() const { return _name; }
786 void set_name(Symbol* n);
787
788 friend class klassKlass;
789
790 public:
791 // jvm support
792 virtual jint compute_modifier_flags(TRAPS) const;
793
794 // JVMTI support
795 virtual jint jvmti_class_status() const;
796
797 // Printing
798 virtual void oop_print_value_on(oop obj, outputStream* st);
799 virtual void oop_print_on (oop obj, outputStream* st);
800
801 // Verification
802 virtual const char* internal_name() const = 0;
803 virtual void oop_verify_on(oop obj, outputStream* st);
804 virtual void oop_verify_old_oop(oop obj, oop* p, bool allow_dirty);
805 virtual void oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty);
806 // tells whether obj is partially constructed (gc during class loading)
807 virtual bool oop_partially_loaded(oop obj) const { return false; }
808 virtual void oop_set_partially_loaded(oop obj) {};
809
810 #ifndef PRODUCT
811 void verify_vtable_index(int index);
812 #endif
813 };
814
815
816 inline oop klassOopDesc::java_mirror() const { return klass_part()->java_mirror(); }
817
818
819 #endif // SHARE_VM_OOPS_KLASS_HPP