Thu, 07 Feb 2013 16:05:48 -0500
Merge
1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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23 */
25 #ifndef SHARE_VM_OOPS_KLASS_HPP
26 #define SHARE_VM_OOPS_KLASS_HPP
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/klassPS.hpp"
33 #include "oops/metadata.hpp"
34 #include "oops/oop.hpp"
35 #include "runtime/orderAccess.hpp"
36 #include "trace/traceMacros.hpp"
37 #include "utilities/accessFlags.hpp"
38 #include "utilities/macros.hpp"
39 #if INCLUDE_ALL_GCS
40 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp"
41 #include "gc_implementation/g1/g1OopClosures.hpp"
42 #include "gc_implementation/parNew/parOopClosures.hpp"
43 #endif // INCLUDE_ALL_GCS
45 //
46 // A Klass provides:
47 // 1: language level class object (method dictionary etc.)
48 // 2: provide vm dispatch behavior for the object
49 // Both functions are combined into one C++ class.
51 // One reason for the oop/klass dichotomy in the implementation is
52 // that we don't want a C++ vtbl pointer in every object. Thus,
53 // normal oops don't have any virtual functions. Instead, they
54 // forward all "virtual" functions to their klass, which does have
55 // a vtbl and does the C++ dispatch depending on the object's
56 // actual type. (See oop.inline.hpp for some of the forwarding code.)
57 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
59 // Klass layout:
60 // [C++ vtbl ptr ] (contained in Metadata)
61 // [layout_helper ]
62 // [super_check_offset ] for fast subtype checks
63 // [name ]
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 // [subklass ] first subclass
74 // [next_sibling ] link to chain additional subklasses
75 // [next_link ]
76 // [class_loader_data]
77 // [modifier_flags]
78 // [access_flags ]
79 // [last_biased_lock_bulk_revocation_time] (64 bits)
80 // [prototype_header]
81 // [biased_lock_revocation_count]
82 // [verify_count ] - not in product
83 // [alloc_count ]
84 // [_modified_oops]
85 // [_accumulated_modified_oops]
86 // [trace_id]
89 // Forward declarations.
90 template <class T> class Array;
91 template <class T> class GrowableArray;
92 class ClassLoaderData;
93 class klassVtable;
94 class ParCompactionManager;
95 class KlassSizeStats;
97 class Klass : public Metadata {
98 friend class VMStructs;
99 protected:
100 // note: put frequently-used fields together at start of klass structure
101 // for better cache behavior (may not make much of a difference but sure won't hurt)
102 enum { _primary_super_limit = 8 };
104 // The "layout helper" is a combined descriptor of object layout.
105 // For klasses which are neither instance nor array, the value is zero.
106 //
107 // For instances, layout helper is a positive number, the instance size.
108 // This size is already passed through align_object_size and scaled to bytes.
109 // The low order bit is set if instances of this class cannot be
110 // allocated using the fastpath.
111 //
112 // For arrays, layout helper is a negative number, containing four
113 // distinct bytes, as follows:
114 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
115 // where:
116 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
117 // hsz is array header size in bytes (i.e., offset of first element)
118 // ebt is the BasicType of the elements
119 // esz is the element size in bytes
120 // This packed word is arranged so as to be quickly unpacked by the
121 // various fast paths that use the various subfields.
122 //
123 // The esz bits can be used directly by a SLL instruction, without masking.
124 //
125 // Note that the array-kind tag looks like 0x00 for instance klasses,
126 // since their length in bytes is always less than 24Mb.
127 //
128 // Final note: This comes first, immediately after C++ vtable,
129 // because it is frequently queried.
130 jint _layout_helper;
132 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
133 // and _primary_supers all help make fast subtype checks. See big discussion
134 // in doc/server_compiler/checktype.txt
135 //
136 // Where to look to observe a supertype (it is &_secondary_super_cache for
137 // secondary supers, else is &_primary_supers[depth()].
138 juint _super_check_offset;
140 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
141 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
142 Symbol* _name;
144 // Cache of last observed secondary supertype
145 Klass* _secondary_super_cache;
146 // Array of all secondary supertypes
147 Array<Klass*>* _secondary_supers;
148 // Ordered list of all primary supertypes
149 Klass* _primary_supers[_primary_super_limit];
150 // java/lang/Class instance mirroring this class
151 oop _java_mirror;
152 // Superclass
153 Klass* _super;
154 // First subclass (NULL if none); _subklass->next_sibling() is next one
155 Klass* _subklass;
156 // Sibling link (or NULL); links all subklasses of a klass
157 Klass* _next_sibling;
159 // All klasses loaded by a class loader are chained through these links
160 Klass* _next_link;
162 // The VM's representation of the ClassLoader used to load this class.
163 // Provide access the corresponding instance java.lang.ClassLoader.
164 ClassLoaderData* _class_loader_data;
166 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
167 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
169 // Biased locking implementation and statistics
170 // (the 64-bit chunk goes first, to avoid some fragmentation)
171 jlong _last_biased_lock_bulk_revocation_time;
172 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
173 jint _biased_lock_revocation_count;
175 #ifndef PRODUCT
176 int _verify_count; // to avoid redundant verifies
177 #endif
179 juint _alloc_count; // allocation profiling support
181 TRACE_DEFINE_KLASS_TRACE_ID;
183 // Remembered sets support for the oops in the klasses.
184 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support)
185 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
187 // Constructor
188 Klass();
190 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS);
192 public:
193 bool is_klass() const volatile { return true; }
195 // super
196 Klass* super() const { return _super; }
197 void set_super(Klass* k) { _super = k; }
199 // initializes _super link, _primary_supers & _secondary_supers arrays
200 void initialize_supers(Klass* k, TRAPS);
201 void initialize_supers_impl1(Klass* k);
202 void initialize_supers_impl2(Klass* k);
204 // klass-specific helper for initializing _secondary_supers
205 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
207 // java_super is the Java-level super type as specified by Class.getSuperClass.
208 virtual Klass* java_super() const { return NULL; }
210 juint super_check_offset() const { return _super_check_offset; }
211 void set_super_check_offset(juint o) { _super_check_offset = o; }
213 Klass* secondary_super_cache() const { return _secondary_super_cache; }
214 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
216 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
217 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
219 // Return the element of the _super chain of the given depth.
220 // If there is no such element, return either NULL or this.
221 Klass* primary_super_of_depth(juint i) const {
222 assert(i < primary_super_limit(), "oob");
223 Klass* super = _primary_supers[i];
224 assert(super == NULL || super->super_depth() == i, "correct display");
225 return super;
226 }
228 // Can this klass be a primary super? False for interfaces and arrays of
229 // interfaces. False also for arrays or classes with long super chains.
230 bool can_be_primary_super() const {
231 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
232 return super_check_offset() != secondary_offset;
233 }
234 virtual bool can_be_primary_super_slow() const;
236 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
237 juint super_depth() const {
238 if (!can_be_primary_super()) {
239 return primary_super_limit();
240 } else {
241 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
242 assert(d < primary_super_limit(), "oob");
243 assert(_primary_supers[d] == this, "proper init");
244 return d;
245 }
246 }
248 // store an oop into a field of a Klass
249 void klass_oop_store(oop* p, oop v);
250 void klass_oop_store(volatile oop* p, oop v);
252 // java mirror
253 oop java_mirror() const { return _java_mirror; }
254 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); }
256 // modifier flags
257 jint modifier_flags() const { return _modifier_flags; }
258 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
260 // size helper
261 int layout_helper() const { return _layout_helper; }
262 void set_layout_helper(int lh) { _layout_helper = lh; }
264 // Note: for instances layout_helper() may include padding.
265 // Use InstanceKlass::contains_field_offset to classify field offsets.
267 // sub/superklass links
268 InstanceKlass* superklass() const;
269 Klass* subklass() const;
270 Klass* next_sibling() const;
271 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
273 void set_next_link(Klass* k) { _next_link = k; }
274 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
276 // class loader data
277 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
278 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
280 // The Klasses are not placed in the Heap, so the Card Table or
281 // the Mod Union Table can't be used to mark when klasses have modified oops.
282 // The CT and MUT bits saves this information for the individual Klasses.
283 void record_modified_oops() { _modified_oops = 1; }
284 void clear_modified_oops() { _modified_oops = 0; }
285 bool has_modified_oops() { return _modified_oops == 1; }
287 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; }
288 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; }
289 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; }
291 protected: // internal accessors
292 Klass* subklass_oop() const { return _subklass; }
293 Klass* next_sibling_oop() const { return _next_sibling; }
294 void set_subklass(Klass* s);
295 void set_next_sibling(Klass* s);
297 public:
298 // Allocation profiling support
299 juint alloc_count() const { return _alloc_count; }
300 void set_alloc_count(juint n) { _alloc_count = n; }
301 virtual juint alloc_size() const = 0;
302 virtual void set_alloc_size(juint n) = 0;
304 // Compiler support
305 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
306 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
307 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
308 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
309 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
310 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
311 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
312 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
313 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
315 // Unpacking layout_helper:
316 enum {
317 _lh_neutral_value = 0, // neutral non-array non-instance value
318 _lh_instance_slow_path_bit = 0x01,
319 _lh_log2_element_size_shift = BitsPerByte*0,
320 _lh_log2_element_size_mask = BitsPerLong-1,
321 _lh_element_type_shift = BitsPerByte*1,
322 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
323 _lh_header_size_shift = BitsPerByte*2,
324 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
325 _lh_array_tag_bits = 2,
326 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
327 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
328 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
329 };
331 static int layout_helper_size_in_bytes(jint lh) {
332 assert(lh > (jint)_lh_neutral_value, "must be instance");
333 return (int) lh & ~_lh_instance_slow_path_bit;
334 }
335 static bool layout_helper_needs_slow_path(jint lh) {
336 assert(lh > (jint)_lh_neutral_value, "must be instance");
337 return (lh & _lh_instance_slow_path_bit) != 0;
338 }
339 static bool layout_helper_is_instance(jint lh) {
340 return (jint)lh > (jint)_lh_neutral_value;
341 }
342 static bool layout_helper_is_array(jint lh) {
343 return (jint)lh < (jint)_lh_neutral_value;
344 }
345 static bool layout_helper_is_typeArray(jint lh) {
346 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
347 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
348 }
349 static bool layout_helper_is_objArray(jint lh) {
350 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
351 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
352 }
353 static int layout_helper_header_size(jint lh) {
354 assert(lh < (jint)_lh_neutral_value, "must be array");
355 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
356 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
357 return hsize;
358 }
359 static BasicType layout_helper_element_type(jint lh) {
360 assert(lh < (jint)_lh_neutral_value, "must be array");
361 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
362 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
363 return (BasicType) btvalue;
364 }
365 static int layout_helper_log2_element_size(jint lh) {
366 assert(lh < (jint)_lh_neutral_value, "must be array");
367 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
368 assert(l2esz <= LogBitsPerLong, "sanity");
369 return l2esz;
370 }
371 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
372 return (tag << _lh_array_tag_shift)
373 | (hsize << _lh_header_size_shift)
374 | ((int)etype << _lh_element_type_shift)
375 | (log2_esize << _lh_log2_element_size_shift);
376 }
377 static jint instance_layout_helper(jint size, bool slow_path_flag) {
378 return (size << LogHeapWordSize)
379 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
380 }
381 static int layout_helper_to_size_helper(jint lh) {
382 assert(lh > (jint)_lh_neutral_value, "must be instance");
383 // Note that the following expression discards _lh_instance_slow_path_bit.
384 return lh >> LogHeapWordSize;
385 }
386 // Out-of-line version computes everything based on the etype:
387 static jint array_layout_helper(BasicType etype);
389 // What is the maximum number of primary superclasses any klass can have?
390 #ifdef PRODUCT
391 static juint primary_super_limit() { return _primary_super_limit; }
392 #else
393 static juint primary_super_limit() {
394 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
395 return FastSuperclassLimit;
396 }
397 #endif
399 // vtables
400 virtual klassVtable* vtable() const { return NULL; }
402 // subclass check
403 bool is_subclass_of(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 bool search_secondary_supers(Klass* k) const;
419 // Find LCA in class hierarchy
420 Klass *LCA( Klass *k );
422 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
423 // if not, throw either an Error or an Exception.
424 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
426 // array copying
427 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
429 // tells if the class should be initialized
430 virtual bool should_be_initialized() const { return false; }
431 // initializes the klass
432 virtual void initialize(TRAPS);
433 // lookup operation for MethodLookupCache
434 friend class MethodLookupCache;
435 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
436 public:
437 Method* lookup_method(Symbol* name, Symbol* signature) const {
438 return uncached_lookup_method(name, signature);
439 }
441 // array class with specific rank
442 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
444 // array class with this klass as element type
445 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
447 // These will return NULL instead of allocating on the heap:
448 // NB: these can block for a mutex, like other functions with TRAPS arg.
449 Klass* array_klass_or_null(int rank);
450 Klass* array_klass_or_null();
452 virtual oop protection_domain() { return NULL; }
454 oop class_loader() const;
456 virtual oop klass_holder() const { return class_loader(); }
458 protected:
459 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
460 virtual Klass* array_klass_impl(bool or_null, TRAPS);
462 public:
463 // CDS support - remove and restore oops from metadata. Oops are not shared.
464 virtual void remove_unshareable_info();
465 virtual void restore_unshareable_info(TRAPS);
467 protected:
468 // computes the subtype relationship
469 virtual bool compute_is_subtype_of(Klass* k);
470 public:
471 // subclass accessor (here for convenience; undefined for non-klass objects)
472 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
473 public:
474 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
475 // These functions describe behavior for the oop not the KLASS.
477 // actual oop size of obj in memory
478 virtual int oop_size(oop obj) const = 0;
480 // Size of klass in word size.
481 virtual int size() const = 0;
482 #if INCLUDE_SERVICES
483 virtual void collect_statistics(KlassSizeStats *sz) const;
484 #endif
486 // Returns the Java name for a class (Resource allocated)
487 // For arrays, this returns the name of the element with a leading '['.
488 // For classes, this returns the name with the package separators
489 // turned into '.'s.
490 const char* external_name() const;
491 // Returns the name for a class (Resource allocated) as the class
492 // would appear in a signature.
493 // For arrays, this returns the name of the element with a leading '['.
494 // For classes, this returns the name with a leading 'L' and a trailing ';'
495 // and the package separators as '/'.
496 virtual const char* signature_name() const;
498 // garbage collection support
499 virtual void oop_follow_contents(oop obj) = 0;
500 virtual int oop_adjust_pointers(oop obj) = 0;
502 // Parallel Scavenge and Parallel Old
503 PARALLEL_GC_DECLS_PV
505 // type testing operations
506 protected:
507 virtual bool oop_is_instance_slow() const { return false; }
508 virtual bool oop_is_array_slow() const { return false; }
509 virtual bool oop_is_objArray_slow() const { return false; }
510 virtual bool oop_is_typeArray_slow() const { return false; }
511 public:
512 virtual bool oop_is_instanceMirror() const { return false; }
513 virtual bool oop_is_instanceRef() const { return false; }
515 // Fast non-virtual versions
516 #ifndef ASSERT
517 #define assert_same_query(xval, xcheck) xval
518 #else
519 private:
520 static bool assert_same_query(bool xval, bool xslow) {
521 assert(xval == xslow, "slow and fast queries agree");
522 return xval;
523 }
524 public:
525 #endif
526 inline bool oop_is_instance() const { return assert_same_query(
527 layout_helper_is_instance(layout_helper()),
528 oop_is_instance_slow()); }
529 inline bool oop_is_array() const { return assert_same_query(
530 layout_helper_is_array(layout_helper()),
531 oop_is_array_slow()); }
532 inline bool oop_is_objArray() const { return assert_same_query(
533 layout_helper_is_objArray(layout_helper()),
534 oop_is_objArray_slow()); }
535 inline bool oop_is_typeArray() const { return assert_same_query(
536 layout_helper_is_typeArray(layout_helper()),
537 oop_is_typeArray_slow()); }
538 #undef assert_same_query
540 // Access flags
541 AccessFlags access_flags() const { return _access_flags; }
542 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
544 bool is_public() const { return _access_flags.is_public(); }
545 bool is_final() const { return _access_flags.is_final(); }
546 bool is_interface() const { return _access_flags.is_interface(); }
547 bool is_abstract() const { return _access_flags.is_abstract(); }
548 bool is_super() const { return _access_flags.is_super(); }
549 bool is_synthetic() const { return _access_flags.is_synthetic(); }
550 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
551 bool has_finalizer() const { return _access_flags.has_finalizer(); }
552 bool has_final_method() const { return _access_flags.has_final_method(); }
553 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
554 void set_has_final_method() { _access_flags.set_has_final_method(); }
555 bool is_cloneable() const { return _access_flags.is_cloneable(); }
556 void set_is_cloneable() { _access_flags.set_is_cloneable(); }
557 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
558 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
559 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
560 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
562 // Biased locking support
563 // Note: the prototype header is always set up to be at least the
564 // prototype markOop. If biased locking is enabled it may further be
565 // biasable and have an epoch.
566 markOop prototype_header() const { return _prototype_header; }
567 // NOTE: once instances of this klass are floating around in the
568 // system, this header must only be updated at a safepoint.
569 // NOTE 2: currently we only ever set the prototype header to the
570 // biasable prototype for instanceKlasses. There is no technical
571 // reason why it could not be done for arrayKlasses aside from
572 // wanting to reduce the initial scope of this optimization. There
573 // are potential problems in setting the bias pattern for
574 // JVM-internal oops.
575 inline void set_prototype_header(markOop header);
576 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
578 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
579 // Atomically increments biased_lock_revocation_count and returns updated value
580 int atomic_incr_biased_lock_revocation_count();
581 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
582 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
583 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
585 TRACE_DEFINE_KLASS_METHODS;
587 // garbage collection support
588 virtual void oops_do(OopClosure* cl);
590 // Iff the class loader (or mirror for anonymous classes) is alive the
591 // Klass is considered alive.
592 // The is_alive closure passed in depends on the Garbage Collector used.
593 bool is_loader_alive(BoolObjectClosure* is_alive);
595 static void clean_weak_klass_links(BoolObjectClosure* is_alive);
597 // Prefetch within oop iterators. This is a macro because we
598 // can't guarantee that the compiler will inline it. In 64-bit
599 // it generally doesn't. Signature is
600 //
601 // static void prefetch_beyond(oop* const start,
602 // oop* const end,
603 // const intx foffset,
604 // const Prefetch::style pstyle);
605 #define prefetch_beyond(start, end, foffset, pstyle) { \
606 const intx foffset_ = (foffset); \
607 const Prefetch::style pstyle_ = (pstyle); \
608 assert(foffset_ > 0, "prefetch beyond, not behind"); \
609 if (pstyle_ != Prefetch::do_none) { \
610 oop* ref = (start); \
611 if (ref < (end)) { \
612 switch (pstyle_) { \
613 case Prefetch::do_read: \
614 Prefetch::read(*ref, foffset_); \
615 break; \
616 case Prefetch::do_write: \
617 Prefetch::write(*ref, foffset_); \
618 break; \
619 default: \
620 ShouldNotReachHere(); \
621 break; \
622 } \
623 } \
624 } \
625 }
627 // iterators
628 virtual int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) = 0;
629 virtual int oop_oop_iterate_v(oop obj, ExtendedOopClosure* blk) {
630 return oop_oop_iterate(obj, blk);
631 }
633 #if INCLUDE_ALL_GCS
634 // In case we don't have a specialized backward scanner use forward
635 // iteration.
636 virtual int oop_oop_iterate_backwards_v(oop obj, ExtendedOopClosure* blk) {
637 return oop_oop_iterate_v(obj, blk);
638 }
639 #endif // INCLUDE_ALL_GCS
641 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
642 // (I don't see why the _m should be required, but without it the Solaris
643 // C++ gives warning messages about overridings of the "oop_oop_iterate"
644 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */
645 virtual int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) = 0;
646 virtual int oop_oop_iterate_v_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
647 return oop_oop_iterate_m(obj, blk, mr);
648 }
650 // Versions of the above iterators specialized to particular subtypes
651 // of OopClosure, to avoid closure virtual calls.
652 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
653 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \
654 /* Default implementation reverts to general version. */ \
655 return oop_oop_iterate(obj, blk); \
656 } \
657 \
658 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
659 (I don't see why the _m should be required, but without it the Solaris \
660 C++ gives warning messages about overridings of the "oop_oop_iterate" \
661 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \
662 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \
663 OopClosureType* blk, \
664 MemRegion mr) { \
665 return oop_oop_iterate_m(obj, blk, mr); \
666 }
668 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
669 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
671 #if INCLUDE_ALL_GCS
672 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
673 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \
674 OopClosureType* blk) { \
675 /* Default implementation reverts to general version. */ \
676 return oop_oop_iterate_backwards_v(obj, blk); \
677 }
679 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
680 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
681 #endif // INCLUDE_ALL_GCS
683 virtual void array_klasses_do(void f(Klass* k)) {}
684 virtual void with_array_klasses_do(void f(Klass* k));
686 // Return self, except for abstract classes with exactly 1
687 // implementor. Then return the 1 concrete implementation.
688 Klass *up_cast_abstract();
690 // klass name
691 Symbol* name() const { return _name; }
692 void set_name(Symbol* n);
694 public:
695 // jvm support
696 virtual jint compute_modifier_flags(TRAPS) const;
698 // JVMTI support
699 virtual jint jvmti_class_status() const;
701 // Printing
702 virtual void print_on(outputStream* st) const;
704 virtual void oop_print_value_on(oop obj, outputStream* st);
705 virtual void oop_print_on (oop obj, outputStream* st);
707 virtual const char* internal_name() const = 0;
709 // Verification
710 virtual void verify_on(outputStream* st);
711 void verify() { verify_on(tty); }
713 #ifndef PRODUCT
714 void verify_vtable_index(int index);
715 #endif
717 virtual void oop_verify_on(oop obj, outputStream* st);
719 private:
720 // barriers used by klass_oop_store
721 void klass_update_barrier_set(oop v);
722 void klass_update_barrier_set_pre(void* p, oop v);
723 };
725 #endif // SHARE_VM_OOPS_KLASS_HPP