Mon, 16 Apr 2012 08:57:18 +0200
4988100: oop_verify_old_oop appears to be dead
Summary: removed oop_verify_old_oop and allow_dirty. Also reviewed by: alexlamsl@gmail.com
Reviewed-by: jmasa, jwilhelm
1 /*
2 * Copyright (c) 1997, 2012, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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/klassOop.hpp"
33 #include "oops/klassPS.hpp"
34 #include "oops/oop.hpp"
35 #include "runtime/orderAccess.hpp"
36 #include "trace/traceMacros.hpp"
37 #include "utilities/accessFlags.hpp"
38 #ifndef SERIALGC
39 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp"
40 #include "gc_implementation/g1/g1OopClosures.hpp"
41 #include "gc_implementation/parNew/parOopClosures.hpp"
42 #endif
44 // A Klass is the part of the klassOop that provides:
45 // 1: language level class object (method dictionary etc.)
46 // 2: provide vm dispatch behavior for the object
47 // Both functions are combined into one C++ class. The toplevel class "Klass"
48 // implements purpose 1 whereas all subclasses provide extra virtual functions
49 // for purpose 2.
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 // [header ] klassOop
61 // [klass pointer ] klassOop
62 // [C++ vtbl ptr ] (contained in Klass_vtbl)
63 // [layout_helper ]
64 // [super_check_offset ] for fast subtype checks
65 // [secondary_super_cache] for fast subtype checks
66 // [secondary_supers ] array of 2ndary supertypes
67 // [primary_supers 0]
68 // [primary_supers 1]
69 // [primary_supers 2]
70 // ...
71 // [primary_supers 7]
72 // [java_mirror ]
73 // [super ]
74 // [name ]
75 // [first subklass]
76 // [next_sibling ] link to chain additional subklasses
77 // [modifier_flags]
78 // [access_flags ]
79 // [verify_count ] - not in product
80 // [alloc_count ]
81 // [last_biased_lock_bulk_revocation_time] (64 bits)
82 // [prototype_header]
83 // [biased_lock_revocation_count]
84 // [trace_id]
87 // Forward declarations.
88 class klassVtable;
89 class KlassHandle;
90 class OrderAccess;
92 // Holder (or cage) for the C++ vtable of each kind of Klass.
93 // We want to tightly constrain the location of the C++ vtable in the overall layout.
94 class Klass_vtbl {
95 protected:
96 // The following virtual exists only to force creation of a C++ vtable,
97 // so that this class truly is the location of the vtable of all Klasses.
98 virtual void unused_initial_virtual() { }
100 public:
101 // The following virtual makes Klass_vtbl play a second role as a
102 // factory protocol for subclasses of Klass ("sub-Klasses").
103 // Here's how it works....
104 //
105 // This VM uses metaobjects as factories for their instances.
106 //
107 // In order to initialize the C++ vtable of a new instance, its
108 // metaobject is forced to use the C++ placed new operator to
109 // allocate the instance. In a typical C++-based system, each
110 // sub-class would have its own factory routine which
111 // directly uses the placed new operator on the desired class,
112 // and then calls the appropriate chain of C++ constructors.
113 //
114 // However, this system uses shared code to performs the first
115 // allocation and initialization steps for all sub-Klasses.
116 // (See base_create_klass() and base_create_array_klass().)
117 // This does not factor neatly into a hierarchy of C++ constructors.
118 // Each caller of these shared "base_create" routines knows
119 // exactly which sub-Klass it is creating, but the shared routine
120 // does not, even though it must perform the actual allocation.
121 //
122 // Therefore, the caller of the shared "base_create" must wrap
123 // the specific placed new call in a virtual function which
124 // performs the actual allocation and vtable set-up. That
125 // virtual function is here, Klass_vtbl::allocate_permanent.
126 //
127 // The arguments to Universe::allocate_permanent() are passed
128 // straight through the placed new operator, which in turn
129 // obtains them directly from this virtual call.
130 //
131 // This virtual is called on a temporary "example instance" of the
132 // sub-Klass being instantiated, a C++ auto variable. The "real"
133 // instance created by this virtual is on the VM heap, where it is
134 // equipped with a klassOopDesc header.
135 //
136 // It is merely an accident of implementation that we use "example
137 // instances", but that is why the virtual function which implements
138 // each sub-Klass factory happens to be defined by the same sub-Klass
139 // for which it creates instances.
140 //
141 // The vtbl_value() call (see below) is used to strip away the
142 // accidental Klass-ness from an "example instance" and present it as
143 // a factory. Think of each factory object as a mere container of the
144 // C++ vtable for the desired sub-Klass. Since C++ does not allow
145 // direct references to vtables, the factory must also be delegated
146 // the task of allocating the instance, but the essential point is
147 // that the factory knows how to initialize the C++ vtable with the
148 // right pointer value. All other common initializations are handled
149 // by the shared "base_create" subroutines.
150 //
151 virtual void* allocate_permanent(KlassHandle& klass, int size, TRAPS) const = 0;
152 void post_new_init_klass(KlassHandle& klass, klassOop obj) const;
154 // Every subclass on which vtbl_value is called must include this macro.
155 // Delay the installation of the klassKlass pointer until after the
156 // the vtable for a new klass has been installed (after the call to new()).
157 #define DEFINE_ALLOCATE_PERMANENT(thisKlass) \
158 void* allocate_permanent(KlassHandle& klass_klass, int size, TRAPS) const { \
159 void* result = new(klass_klass, size, THREAD) thisKlass(); \
160 if (HAS_PENDING_EXCEPTION) return NULL; \
161 klassOop new_klass = ((Klass*) result)->as_klassOop(); \
162 OrderAccess::storestore(); \
163 post_new_init_klass(klass_klass, new_klass); \
164 return result; \
165 }
167 bool null_vtbl() { return *(intptr_t*)this == 0; }
169 protected:
170 void* operator new(size_t ignored, KlassHandle& klass, int size, TRAPS);
171 };
174 class Klass : public Klass_vtbl {
175 friend class VMStructs;
176 protected:
177 // note: put frequently-used fields together at start of klass structure
178 // for better cache behavior (may not make much of a difference but sure won't hurt)
179 enum { _primary_super_limit = 8 };
181 // The "layout helper" is a combined descriptor of object layout.
182 // For klasses which are neither instance nor array, the value is zero.
183 //
184 // For instances, layout helper is a positive number, the instance size.
185 // This size is already passed through align_object_size and scaled to bytes.
186 // The low order bit is set if instances of this class cannot be
187 // allocated using the fastpath.
188 //
189 // For arrays, layout helper is a negative number, containing four
190 // distinct bytes, as follows:
191 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
192 // where:
193 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
194 // hsz is array header size in bytes (i.e., offset of first element)
195 // ebt is the BasicType of the elements
196 // esz is the element size in bytes
197 // This packed word is arranged so as to be quickly unpacked by the
198 // various fast paths that use the various subfields.
199 //
200 // The esz bits can be used directly by a SLL instruction, without masking.
201 //
202 // Note that the array-kind tag looks like 0x00 for instance klasses,
203 // since their length in bytes is always less than 24Mb.
204 //
205 // Final note: This comes first, immediately after Klass_vtbl,
206 // because it is frequently queried.
207 jint _layout_helper;
209 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
210 // and _primary_supers all help make fast subtype checks. See big discussion
211 // in doc/server_compiler/checktype.txt
212 //
213 // Where to look to observe a supertype (it is &_secondary_super_cache for
214 // secondary supers, else is &_primary_supers[depth()].
215 juint _super_check_offset;
217 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
218 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
219 Symbol* _name;
221 public:
222 oop* oop_block_beg() const { return adr_secondary_super_cache(); }
223 oop* oop_block_end() const { return adr_next_sibling() + 1; }
225 protected:
226 //
227 // The oop block. All oop fields must be declared here and only oop fields
228 // may be declared here. In addition, the first and last fields in this block
229 // must remain first and last, unless oop_block_beg() and/or oop_block_end()
230 // are updated. Grouping the oop fields in a single block simplifies oop
231 // iteration.
232 //
234 // Cache of last observed secondary supertype
235 klassOop _secondary_super_cache;
236 // Array of all secondary supertypes
237 objArrayOop _secondary_supers;
238 // Ordered list of all primary supertypes
239 klassOop _primary_supers[_primary_super_limit];
240 // java/lang/Class instance mirroring this class
241 oop _java_mirror;
242 // Superclass
243 klassOop _super;
244 // First subclass (NULL if none); _subklass->next_sibling() is next one
245 klassOop _subklass;
246 // Sibling link (or NULL); links all subklasses of a klass
247 klassOop _next_sibling;
249 //
250 // End of the oop block.
251 //
253 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
254 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
256 #ifndef PRODUCT
257 int _verify_count; // to avoid redundant verifies
258 #endif
260 juint _alloc_count; // allocation profiling support - update klass_size_in_bytes() if moved/deleted
262 // Biased locking implementation and statistics
263 // (the 64-bit chunk goes first, to avoid some fragmentation)
264 jlong _last_biased_lock_bulk_revocation_time;
265 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
266 jint _biased_lock_revocation_count;
268 TRACE_DEFINE_KLASS_TRACE_ID;
269 public:
271 // returns the enclosing klassOop
272 klassOop as_klassOop() const {
273 // see klassOop.hpp for layout.
274 return (klassOop) (((char*) this) - sizeof(klassOopDesc));
275 }
277 public:
278 // Allocation
279 const Klass_vtbl& vtbl_value() const { return *this; } // used only on "example instances"
280 static KlassHandle base_create_klass(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
281 static klassOop base_create_klass_oop(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
283 // super
284 klassOop super() const { return _super; }
285 void set_super(klassOop k) { oop_store_without_check((oop*) &_super, (oop) k); }
287 // initializes _super link, _primary_supers & _secondary_supers arrays
288 void initialize_supers(klassOop k, TRAPS);
289 void initialize_supers_impl1(klassOop k);
290 void initialize_supers_impl2(klassOop k);
292 // klass-specific helper for initializing _secondary_supers
293 virtual objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS);
295 // java_super is the Java-level super type as specified by Class.getSuperClass.
296 virtual klassOop java_super() const { return NULL; }
298 juint super_check_offset() const { return _super_check_offset; }
299 void set_super_check_offset(juint o) { _super_check_offset = o; }
301 klassOop secondary_super_cache() const { return _secondary_super_cache; }
302 void set_secondary_super_cache(klassOop k) { oop_store_without_check((oop*) &_secondary_super_cache, (oop) k); }
304 objArrayOop secondary_supers() const { return _secondary_supers; }
305 void set_secondary_supers(objArrayOop k) { oop_store_without_check((oop*) &_secondary_supers, (oop) k); }
307 // Return the element of the _super chain of the given depth.
308 // If there is no such element, return either NULL or this.
309 klassOop primary_super_of_depth(juint i) const {
310 assert(i < primary_super_limit(), "oob");
311 klassOop super = _primary_supers[i];
312 assert(super == NULL || super->klass_part()->super_depth() == i, "correct display");
313 return super;
314 }
316 // Can this klass be a primary super? False for interfaces and arrays of
317 // interfaces. False also for arrays or classes with long super chains.
318 bool can_be_primary_super() const {
319 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
320 return super_check_offset() != secondary_offset;
321 }
322 virtual bool can_be_primary_super_slow() const;
324 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
325 juint super_depth() const {
326 if (!can_be_primary_super()) {
327 return primary_super_limit();
328 } else {
329 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(klassOop);
330 assert(d < primary_super_limit(), "oob");
331 assert(_primary_supers[d] == as_klassOop(), "proper init");
332 return d;
333 }
334 }
336 // java mirror
337 oop java_mirror() const { return _java_mirror; }
338 void set_java_mirror(oop m) { oop_store((oop*) &_java_mirror, m); }
340 // modifier flags
341 jint modifier_flags() const { return _modifier_flags; }
342 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
344 // size helper
345 int layout_helper() const { return _layout_helper; }
346 void set_layout_helper(int lh) { _layout_helper = lh; }
348 // Note: for instances layout_helper() may include padding.
349 // Use instanceKlass::contains_field_offset to classify field offsets.
351 // sub/superklass links
352 instanceKlass* superklass() const;
353 Klass* subklass() const;
354 Klass* next_sibling() const;
355 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
356 void remove_from_sibling_list(); // remove receiver from sibling list
357 protected: // internal accessors
358 klassOop subklass_oop() const { return _subklass; }
359 klassOop next_sibling_oop() const { return _next_sibling; }
360 void set_subklass(klassOop s);
361 void set_next_sibling(klassOop s);
363 oop* adr_super() const { return (oop*)&_super; }
364 oop* adr_primary_supers() const { return (oop*)&_primary_supers[0]; }
365 oop* adr_secondary_super_cache() const { return (oop*)&_secondary_super_cache; }
366 oop* adr_secondary_supers()const { return (oop*)&_secondary_supers; }
367 oop* adr_java_mirror() const { return (oop*)&_java_mirror; }
368 oop* adr_subklass() const { return (oop*)&_subklass; }
369 oop* adr_next_sibling() const { return (oop*)&_next_sibling; }
371 public:
372 // Allocation profiling support
373 juint alloc_count() const { return _alloc_count; }
374 void set_alloc_count(juint n) { _alloc_count = n; }
375 virtual juint alloc_size() const = 0;
376 virtual void set_alloc_size(juint n) = 0;
378 // Compiler support
379 static ByteSize super_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _super)); }
380 static ByteSize super_check_offset_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _super_check_offset)); }
381 static ByteSize primary_supers_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _primary_supers)); }
382 static ByteSize secondary_super_cache_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _secondary_super_cache)); }
383 static ByteSize secondary_supers_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _secondary_supers)); }
384 static ByteSize java_mirror_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _java_mirror)); }
385 static ByteSize modifier_flags_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _modifier_flags)); }
386 static ByteSize layout_helper_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _layout_helper)); }
387 static ByteSize access_flags_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _access_flags)); }
389 // Unpacking layout_helper:
390 enum {
391 _lh_neutral_value = 0, // neutral non-array non-instance value
392 _lh_instance_slow_path_bit = 0x01,
393 _lh_log2_element_size_shift = BitsPerByte*0,
394 _lh_log2_element_size_mask = BitsPerLong-1,
395 _lh_element_type_shift = BitsPerByte*1,
396 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
397 _lh_header_size_shift = BitsPerByte*2,
398 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
399 _lh_array_tag_bits = 2,
400 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
401 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
402 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
403 };
405 static int layout_helper_size_in_bytes(jint lh) {
406 assert(lh > (jint)_lh_neutral_value, "must be instance");
407 return (int) lh & ~_lh_instance_slow_path_bit;
408 }
409 static bool layout_helper_needs_slow_path(jint lh) {
410 assert(lh > (jint)_lh_neutral_value, "must be instance");
411 return (lh & _lh_instance_slow_path_bit) != 0;
412 }
413 static bool layout_helper_is_instance(jint lh) {
414 return (jint)lh > (jint)_lh_neutral_value;
415 }
416 static bool layout_helper_is_javaArray(jint lh) {
417 return (jint)lh < (jint)_lh_neutral_value;
418 }
419 static bool layout_helper_is_typeArray(jint lh) {
420 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
421 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
422 }
423 static bool layout_helper_is_objArray(jint lh) {
424 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
425 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
426 }
427 static int layout_helper_header_size(jint lh) {
428 assert(lh < (jint)_lh_neutral_value, "must be array");
429 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
430 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
431 return hsize;
432 }
433 static BasicType layout_helper_element_type(jint lh) {
434 assert(lh < (jint)_lh_neutral_value, "must be array");
435 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
436 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
437 return (BasicType) btvalue;
438 }
439 static int layout_helper_log2_element_size(jint lh) {
440 assert(lh < (jint)_lh_neutral_value, "must be array");
441 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
442 assert(l2esz <= LogBitsPerLong, "sanity");
443 return l2esz;
444 }
445 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
446 return (tag << _lh_array_tag_shift)
447 | (hsize << _lh_header_size_shift)
448 | ((int)etype << _lh_element_type_shift)
449 | (log2_esize << _lh_log2_element_size_shift);
450 }
451 static jint instance_layout_helper(jint size, bool slow_path_flag) {
452 return (size << LogHeapWordSize)
453 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
454 }
455 static int layout_helper_to_size_helper(jint lh) {
456 assert(lh > (jint)_lh_neutral_value, "must be instance");
457 // Note that the following expression discards _lh_instance_slow_path_bit.
458 return lh >> LogHeapWordSize;
459 }
460 // Out-of-line version computes everything based on the etype:
461 static jint array_layout_helper(BasicType etype);
463 // What is the maximum number of primary superclasses any klass can have?
464 #ifdef PRODUCT
465 static juint primary_super_limit() { return _primary_super_limit; }
466 #else
467 static juint primary_super_limit() {
468 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
469 return FastSuperclassLimit;
470 }
471 #endif
473 // vtables
474 virtual klassVtable* vtable() const { return NULL; }
476 static int klass_size_in_bytes() { return offset_of(Klass, _alloc_count) + sizeof(juint); } // all "visible" fields
478 // subclass check
479 bool is_subclass_of(klassOop k) const;
480 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
481 bool is_subtype_of(klassOop k) const {
482 juint off = k->klass_part()->super_check_offset();
483 klassOop sup = *(klassOop*)( (address)as_klassOop() + off );
484 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
485 if (sup == k) {
486 return true;
487 } else if (off != secondary_offset) {
488 return false;
489 } else {
490 return search_secondary_supers(k);
491 }
492 }
493 bool search_secondary_supers(klassOop k) const;
495 // Find LCA in class hierarchy
496 Klass *LCA( Klass *k );
498 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
499 // if not, throw either an Error or an Exception.
500 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
502 // Casting
503 static Klass* cast(klassOop k) {
504 assert(k->is_klass(), "cast to Klass");
505 return k->klass_part();
506 }
508 // array copying
509 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
511 // tells if the class should be initialized
512 virtual bool should_be_initialized() const { return false; }
513 // initializes the klass
514 virtual void initialize(TRAPS);
515 // lookup operation for MethodLookupCache
516 friend class MethodLookupCache;
517 virtual methodOop uncached_lookup_method(Symbol* name, Symbol* signature) const;
518 public:
519 methodOop lookup_method(Symbol* name, Symbol* signature) const {
520 return uncached_lookup_method(name, signature);
521 }
523 // array class with specific rank
524 klassOop array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
526 // array class with this klass as element type
527 klassOop array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
529 // These will return NULL instead of allocating on the heap:
530 // NB: these can block for a mutex, like other functions with TRAPS arg.
531 klassOop array_klass_or_null(int rank);
532 klassOop array_klass_or_null();
534 virtual oop protection_domain() { return NULL; }
535 virtual oop class_loader() const { return NULL; }
537 protected:
538 virtual klassOop array_klass_impl(bool or_null, int rank, TRAPS);
539 virtual klassOop array_klass_impl(bool or_null, TRAPS);
541 public:
542 virtual void remove_unshareable_info();
543 virtual void shared_symbols_iterate(SymbolClosure* closure);
545 protected:
546 // computes the subtype relationship
547 virtual bool compute_is_subtype_of(klassOop k);
548 public:
549 // subclass accessor (here for convenience; undefined for non-klass objects)
550 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
551 public:
552 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
553 // These functions describe behavior for the oop not the KLASS.
555 // actual oop size of obj in memory
556 virtual int oop_size(oop obj) const = 0;
558 // actual oop size of this klass in memory
559 virtual int klass_oop_size() const = 0;
561 // Returns the Java name for a class (Resource allocated)
562 // For arrays, this returns the name of the element with a leading '['.
563 // For classes, this returns the name with the package separators
564 // turned into '.'s.
565 const char* external_name() const;
566 // Returns the name for a class (Resource allocated) as the class
567 // would appear in a signature.
568 // For arrays, this returns the name of the element with a leading '['.
569 // For classes, this returns the name with a leading 'L' and a trailing ';'
570 // and the package separators as '/'.
571 virtual const char* signature_name() const;
573 // garbage collection support
574 virtual void oop_follow_contents(oop obj) = 0;
575 virtual int oop_adjust_pointers(oop obj) = 0;
577 // Parallel Scavenge and Parallel Old
578 PARALLEL_GC_DECLS_PV
580 public:
581 // type testing operations
582 virtual bool oop_is_instance_slow() const { return false; }
583 virtual bool oop_is_instanceMirror() const { return false; }
584 virtual bool oop_is_instanceRef() const { return false; }
585 virtual bool oop_is_array() const { return false; }
586 virtual bool oop_is_objArray_slow() const { return false; }
587 virtual bool oop_is_klass() const { return false; }
588 virtual bool oop_is_thread() const { return false; }
589 virtual bool oop_is_method() const { return false; }
590 virtual bool oop_is_constMethod() const { return false; }
591 virtual bool oop_is_methodData() const { return false; }
592 virtual bool oop_is_constantPool() const { return false; }
593 virtual bool oop_is_constantPoolCache() const { return false; }
594 virtual bool oop_is_typeArray_slow() const { return false; }
595 virtual bool oop_is_arrayKlass() const { return false; }
596 virtual bool oop_is_objArrayKlass() const { return false; }
597 virtual bool oop_is_typeArrayKlass() const { return false; }
598 virtual bool oop_is_compiledICHolder() const { return false; }
599 virtual bool oop_is_instanceKlass() const { return false; }
601 bool oop_is_javaArray_slow() const {
602 return oop_is_objArray_slow() || oop_is_typeArray_slow();
603 }
605 // Fast non-virtual versions, used by oop.inline.hpp and elsewhere:
606 #ifndef ASSERT
607 #define assert_same_query(xval, xcheck) xval
608 #else
609 private:
610 static bool assert_same_query(bool xval, bool xslow) {
611 assert(xval == xslow, "slow and fast queries agree");
612 return xval;
613 }
614 public:
615 #endif
616 inline bool oop_is_instance() const { return assert_same_query(
617 layout_helper_is_instance(layout_helper()),
618 oop_is_instance_slow()); }
619 inline bool oop_is_javaArray() const { return assert_same_query(
620 layout_helper_is_javaArray(layout_helper()),
621 oop_is_javaArray_slow()); }
622 inline bool oop_is_objArray() const { return assert_same_query(
623 layout_helper_is_objArray(layout_helper()),
624 oop_is_objArray_slow()); }
625 inline bool oop_is_typeArray() const { return assert_same_query(
626 layout_helper_is_typeArray(layout_helper()),
627 oop_is_typeArray_slow()); }
628 #undef assert_same_query
630 // Unless overridden, oop is parsable if it has a klass pointer.
631 // Parsability of an object is object specific.
632 virtual bool oop_is_parsable(oop obj) const { return true; }
634 // Unless overridden, oop is safe for concurrent GC processing
635 // after its allocation is complete. The exception to
636 // this is the case where objects are changed after allocation.
637 // Class redefinition is one of the known exceptions. During
638 // class redefinition, an allocated class can changed in order
639 // order to create a merged class (the combiniation of the
640 // old class definition that has to be perserved and the new class
641 // definition which is being created.
642 virtual bool oop_is_conc_safe(oop obj) const { return true; }
644 // Access flags
645 AccessFlags access_flags() const { return _access_flags; }
646 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
648 bool is_public() const { return _access_flags.is_public(); }
649 bool is_final() const { return _access_flags.is_final(); }
650 bool is_interface() const { return _access_flags.is_interface(); }
651 bool is_abstract() const { return _access_flags.is_abstract(); }
652 bool is_super() const { return _access_flags.is_super(); }
653 bool is_synthetic() const { return _access_flags.is_synthetic(); }
654 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
655 bool has_finalizer() const { return _access_flags.has_finalizer(); }
656 bool has_final_method() const { return _access_flags.has_final_method(); }
657 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
658 void set_has_final_method() { _access_flags.set_has_final_method(); }
659 bool is_cloneable() const { return _access_flags.is_cloneable(); }
660 void set_is_cloneable() { _access_flags.set_is_cloneable(); }
661 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
662 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
663 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
664 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
666 // Biased locking support
667 // Note: the prototype header is always set up to be at least the
668 // prototype markOop. If biased locking is enabled it may further be
669 // biasable and have an epoch.
670 markOop prototype_header() const { return _prototype_header; }
671 // NOTE: once instances of this klass are floating around in the
672 // system, this header must only be updated at a safepoint.
673 // NOTE 2: currently we only ever set the prototype header to the
674 // biasable prototype for instanceKlasses. There is no technical
675 // reason why it could not be done for arrayKlasses aside from
676 // wanting to reduce the initial scope of this optimization. There
677 // are potential problems in setting the bias pattern for
678 // JVM-internal oops.
679 inline void set_prototype_header(markOop header);
680 static ByteSize prototype_header_offset() { return in_ByteSize(sizeof(klassOopDesc) + offset_of(Klass, _prototype_header)); }
682 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
683 // Atomically increments biased_lock_revocation_count and returns updated value
684 int atomic_incr_biased_lock_revocation_count();
685 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
686 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
687 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
689 TRACE_DEFINE_KLASS_METHODS;
691 // garbage collection support
692 virtual void follow_weak_klass_links(
693 BoolObjectClosure* is_alive, OopClosure* keep_alive);
695 // Prefetch within oop iterators. This is a macro because we
696 // can't guarantee that the compiler will inline it. In 64-bit
697 // it generally doesn't. Signature is
698 //
699 // static void prefetch_beyond(oop* const start,
700 // oop* const end,
701 // const intx foffset,
702 // const Prefetch::style pstyle);
703 #define prefetch_beyond(start, end, foffset, pstyle) { \
704 const intx foffset_ = (foffset); \
705 const Prefetch::style pstyle_ = (pstyle); \
706 assert(foffset_ > 0, "prefetch beyond, not behind"); \
707 if (pstyle_ != Prefetch::do_none) { \
708 oop* ref = (start); \
709 if (ref < (end)) { \
710 switch (pstyle_) { \
711 case Prefetch::do_read: \
712 Prefetch::read(*ref, foffset_); \
713 break; \
714 case Prefetch::do_write: \
715 Prefetch::write(*ref, foffset_); \
716 break; \
717 default: \
718 ShouldNotReachHere(); \
719 break; \
720 } \
721 } \
722 } \
723 }
725 // iterators
726 virtual int oop_oop_iterate(oop obj, OopClosure* blk) = 0;
727 virtual int oop_oop_iterate_v(oop obj, OopClosure* blk) {
728 return oop_oop_iterate(obj, blk);
729 }
731 #ifndef SERIALGC
732 // In case we don't have a specialized backward scanner use forward
733 // iteration.
734 virtual int oop_oop_iterate_backwards_v(oop obj, OopClosure* blk) {
735 return oop_oop_iterate_v(obj, blk);
736 }
737 #endif // !SERIALGC
739 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
740 // (I don't see why the _m should be required, but without it the Solaris
741 // C++ gives warning messages about overridings of the "oop_oop_iterate"
742 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */
743 virtual int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) = 0;
744 virtual int oop_oop_iterate_v_m(oop obj, OopClosure* blk, MemRegion mr) {
745 return oop_oop_iterate_m(obj, blk, mr);
746 }
748 // Versions of the above iterators specialized to particular subtypes
749 // of OopClosure, to avoid closure virtual calls.
750 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
751 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \
752 /* Default implementation reverts to general version. */ \
753 return oop_oop_iterate(obj, blk); \
754 } \
755 \
756 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
757 (I don't see why the _m should be required, but without it the Solaris \
758 C++ gives warning messages about overridings of the "oop_oop_iterate" \
759 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \
760 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \
761 OopClosureType* blk, \
762 MemRegion mr) { \
763 return oop_oop_iterate_m(obj, blk, mr); \
764 }
766 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
767 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
769 #ifndef SERIALGC
770 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
771 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \
772 OopClosureType* blk) { \
773 /* Default implementation reverts to general version. */ \
774 return oop_oop_iterate_backwards_v(obj, blk); \
775 }
777 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
778 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
779 #endif // !SERIALGC
781 virtual void array_klasses_do(void f(klassOop k)) {}
782 virtual void with_array_klasses_do(void f(klassOop k));
784 // Return self, except for abstract classes with exactly 1
785 // implementor. Then return the 1 concrete implementation.
786 Klass *up_cast_abstract();
788 // klass name
789 Symbol* name() const { return _name; }
790 void set_name(Symbol* n);
792 friend class klassKlass;
794 public:
795 // jvm support
796 virtual jint compute_modifier_flags(TRAPS) const;
798 // JVMTI support
799 virtual jint jvmti_class_status() const;
801 // Printing
802 virtual void oop_print_value_on(oop obj, outputStream* st);
803 virtual void oop_print_on (oop obj, outputStream* st);
805 // Verification
806 virtual const char* internal_name() const = 0;
807 virtual void oop_verify_on(oop obj, outputStream* st);
808 // tells whether obj is partially constructed (gc during class loading)
809 virtual bool oop_partially_loaded(oop obj) const { return false; }
810 virtual void oop_set_partially_loaded(oop obj) {};
812 #ifndef PRODUCT
813 void verify_vtable_index(int index);
814 #endif
815 };
818 inline oop klassOopDesc::java_mirror() const { return klass_part()->java_mirror(); }
821 #endif // SHARE_VM_OOPS_KLASS_HPP