Tue, 25 Feb 2014 18:16:24 +0100
8031752: Failed speculative optimizations should be reattempted when root of compilation is different
Summary: support for speculative traps that keep track of the root of the compilation in which a trap occurs.
Reviewed-by: kvn, twisti
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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 // [_modified_oops]
83 // [_accumulated_modified_oops]
84 // [trace_id]
87 // Forward declarations.
88 template <class T> class Array;
89 template <class T> class GrowableArray;
90 class ClassLoaderData;
91 class klassVtable;
92 class ParCompactionManager;
93 class KlassSizeStats;
95 class Klass : public Metadata {
96 friend class VMStructs;
97 protected:
98 // note: put frequently-used fields together at start of klass structure
99 // for better cache behavior (may not make much of a difference but sure won't hurt)
100 enum { _primary_super_limit = 8 };
102 // The "layout helper" is a combined descriptor of object layout.
103 // For klasses which are neither instance nor array, the value is zero.
104 //
105 // For instances, layout helper is a positive number, the instance size.
106 // This size is already passed through align_object_size and scaled to bytes.
107 // The low order bit is set if instances of this class cannot be
108 // allocated using the fastpath.
109 //
110 // For arrays, layout helper is a negative number, containing four
111 // distinct bytes, as follows:
112 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
113 // where:
114 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
115 // hsz is array header size in bytes (i.e., offset of first element)
116 // ebt is the BasicType of the elements
117 // esz is the element size in bytes
118 // This packed word is arranged so as to be quickly unpacked by the
119 // various fast paths that use the various subfields.
120 //
121 // The esz bits can be used directly by a SLL instruction, without masking.
122 //
123 // Note that the array-kind tag looks like 0x00 for instance klasses,
124 // since their length in bytes is always less than 24Mb.
125 //
126 // Final note: This comes first, immediately after C++ vtable,
127 // because it is frequently queried.
128 jint _layout_helper;
130 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
131 // and _primary_supers all help make fast subtype checks. See big discussion
132 // in doc/server_compiler/checktype.txt
133 //
134 // Where to look to observe a supertype (it is &_secondary_super_cache for
135 // secondary supers, else is &_primary_supers[depth()].
136 juint _super_check_offset;
138 // Class name. Instance classes: java/lang/String, etc. Array classes: [I,
139 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes.
140 Symbol* _name;
142 // Cache of last observed secondary supertype
143 Klass* _secondary_super_cache;
144 // Array of all secondary supertypes
145 Array<Klass*>* _secondary_supers;
146 // Ordered list of all primary supertypes
147 Klass* _primary_supers[_primary_super_limit];
148 // java/lang/Class instance mirroring this class
149 oop _java_mirror;
150 // Superclass
151 Klass* _super;
152 // First subclass (NULL if none); _subklass->next_sibling() is next one
153 Klass* _subklass;
154 // Sibling link (or NULL); links all subklasses of a klass
155 Klass* _next_sibling;
157 // All klasses loaded by a class loader are chained through these links
158 Klass* _next_link;
160 // The VM's representation of the ClassLoader used to load this class.
161 // Provide access the corresponding instance java.lang.ClassLoader.
162 ClassLoaderData* _class_loader_data;
164 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
165 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
167 // Biased locking implementation and statistics
168 // (the 64-bit chunk goes first, to avoid some fragmentation)
169 jlong _last_biased_lock_bulk_revocation_time;
170 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type
171 jint _biased_lock_revocation_count;
173 TRACE_DEFINE_KLASS_TRACE_ID;
175 // Remembered sets support for the oops in the klasses.
176 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support)
177 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
179 // Constructor
180 Klass();
182 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw();
184 public:
185 bool is_klass() const volatile { return true; }
187 // super
188 Klass* super() const { return _super; }
189 void set_super(Klass* k) { _super = k; }
191 // initializes _super link, _primary_supers & _secondary_supers arrays
192 void initialize_supers(Klass* k, TRAPS);
193 void initialize_supers_impl1(Klass* k);
194 void initialize_supers_impl2(Klass* k);
196 // klass-specific helper for initializing _secondary_supers
197 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
199 // java_super is the Java-level super type as specified by Class.getSuperClass.
200 virtual Klass* java_super() const { return NULL; }
202 juint super_check_offset() const { return _super_check_offset; }
203 void set_super_check_offset(juint o) { _super_check_offset = o; }
205 Klass* secondary_super_cache() const { return _secondary_super_cache; }
206 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; }
208 Array<Klass*>* secondary_supers() const { return _secondary_supers; }
209 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
211 // Return the element of the _super chain of the given depth.
212 // If there is no such element, return either NULL or this.
213 Klass* primary_super_of_depth(juint i) const {
214 assert(i < primary_super_limit(), "oob");
215 Klass* super = _primary_supers[i];
216 assert(super == NULL || super->super_depth() == i, "correct display");
217 return super;
218 }
220 // Can this klass be a primary super? False for interfaces and arrays of
221 // interfaces. False also for arrays or classes with long super chains.
222 bool can_be_primary_super() const {
223 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
224 return super_check_offset() != secondary_offset;
225 }
226 virtual bool can_be_primary_super_slow() const;
228 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
229 juint super_depth() const {
230 if (!can_be_primary_super()) {
231 return primary_super_limit();
232 } else {
233 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*);
234 assert(d < primary_super_limit(), "oob");
235 assert(_primary_supers[d] == this, "proper init");
236 return d;
237 }
238 }
240 // store an oop into a field of a Klass
241 void klass_oop_store(oop* p, oop v);
242 void klass_oop_store(volatile oop* p, oop v);
244 // java mirror
245 oop java_mirror() const { return _java_mirror; }
246 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); }
248 // modifier flags
249 jint modifier_flags() const { return _modifier_flags; }
250 void set_modifier_flags(jint flags) { _modifier_flags = flags; }
252 // size helper
253 int layout_helper() const { return _layout_helper; }
254 void set_layout_helper(int lh) { _layout_helper = lh; }
256 // Note: for instances layout_helper() may include padding.
257 // Use InstanceKlass::contains_field_offset to classify field offsets.
259 // sub/superklass links
260 InstanceKlass* superklass() const;
261 Klass* subklass() const;
262 Klass* next_sibling() const;
263 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
265 void set_next_link(Klass* k) { _next_link = k; }
266 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
268 // class loader data
269 ClassLoaderData* class_loader_data() const { return _class_loader_data; }
270 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; }
272 // The Klasses are not placed in the Heap, so the Card Table or
273 // the Mod Union Table can't be used to mark when klasses have modified oops.
274 // The CT and MUT bits saves this information for the individual Klasses.
275 void record_modified_oops() { _modified_oops = 1; }
276 void clear_modified_oops() { _modified_oops = 0; }
277 bool has_modified_oops() { return _modified_oops == 1; }
279 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; }
280 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; }
281 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; }
283 protected: // internal accessors
284 Klass* subklass_oop() const { return _subklass; }
285 Klass* next_sibling_oop() const { return _next_sibling; }
286 void set_subklass(Klass* s);
287 void set_next_sibling(Klass* s);
289 public:
291 // Compiler support
292 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
293 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
294 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
295 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
296 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
297 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
298 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
299 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
300 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
302 // Unpacking layout_helper:
303 enum {
304 _lh_neutral_value = 0, // neutral non-array non-instance value
305 _lh_instance_slow_path_bit = 0x01,
306 _lh_log2_element_size_shift = BitsPerByte*0,
307 _lh_log2_element_size_mask = BitsPerLong-1,
308 _lh_element_type_shift = BitsPerByte*1,
309 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask
310 _lh_header_size_shift = BitsPerByte*2,
311 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask
312 _lh_array_tag_bits = 2,
313 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits,
314 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30
315 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30
316 };
318 static int layout_helper_size_in_bytes(jint lh) {
319 assert(lh > (jint)_lh_neutral_value, "must be instance");
320 return (int) lh & ~_lh_instance_slow_path_bit;
321 }
322 static bool layout_helper_needs_slow_path(jint lh) {
323 assert(lh > (jint)_lh_neutral_value, "must be instance");
324 return (lh & _lh_instance_slow_path_bit) != 0;
325 }
326 static bool layout_helper_is_instance(jint lh) {
327 return (jint)lh > (jint)_lh_neutral_value;
328 }
329 static bool layout_helper_is_array(jint lh) {
330 return (jint)lh < (jint)_lh_neutral_value;
331 }
332 static bool layout_helper_is_typeArray(jint lh) {
333 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
334 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
335 }
336 static bool layout_helper_is_objArray(jint lh) {
337 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
338 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
339 }
340 static int layout_helper_header_size(jint lh) {
341 assert(lh < (jint)_lh_neutral_value, "must be array");
342 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
343 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
344 return hsize;
345 }
346 static BasicType layout_helper_element_type(jint lh) {
347 assert(lh < (jint)_lh_neutral_value, "must be array");
348 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
349 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
350 return (BasicType) btvalue;
351 }
352 static int layout_helper_log2_element_size(jint lh) {
353 assert(lh < (jint)_lh_neutral_value, "must be array");
354 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
355 assert(l2esz <= LogBitsPerLong,
356 err_msg("sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh));
357 return l2esz;
358 }
359 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
360 return (tag << _lh_array_tag_shift)
361 | (hsize << _lh_header_size_shift)
362 | ((int)etype << _lh_element_type_shift)
363 | (log2_esize << _lh_log2_element_size_shift);
364 }
365 static jint instance_layout_helper(jint size, bool slow_path_flag) {
366 return (size << LogHeapWordSize)
367 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
368 }
369 static int layout_helper_to_size_helper(jint lh) {
370 assert(lh > (jint)_lh_neutral_value, "must be instance");
371 // Note that the following expression discards _lh_instance_slow_path_bit.
372 return lh >> LogHeapWordSize;
373 }
374 // Out-of-line version computes everything based on the etype:
375 static jint array_layout_helper(BasicType etype);
377 // What is the maximum number of primary superclasses any klass can have?
378 #ifdef PRODUCT
379 static juint primary_super_limit() { return _primary_super_limit; }
380 #else
381 static juint primary_super_limit() {
382 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
383 return FastSuperclassLimit;
384 }
385 #endif
387 // vtables
388 virtual klassVtable* vtable() const { return NULL; }
389 virtual int vtable_length() const { return 0; }
391 // subclass check
392 bool is_subclass_of(const Klass* k) const;
393 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
394 bool is_subtype_of(Klass* k) const {
395 juint off = k->super_check_offset();
396 Klass* sup = *(Klass**)( (address)this + off );
397 const juint secondary_offset = in_bytes(secondary_super_cache_offset());
398 if (sup == k) {
399 return true;
400 } else if (off != secondary_offset) {
401 return false;
402 } else {
403 return search_secondary_supers(k);
404 }
405 }
406 bool search_secondary_supers(Klass* k) const;
408 // Find LCA in class hierarchy
409 Klass *LCA( Klass *k );
411 // Check whether reflection/jni/jvm code is allowed to instantiate this class;
412 // if not, throw either an Error or an Exception.
413 virtual void check_valid_for_instantiation(bool throwError, TRAPS);
415 // array copying
416 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
418 // tells if the class should be initialized
419 virtual bool should_be_initialized() const { return false; }
420 // initializes the klass
421 virtual void initialize(TRAPS);
422 // lookup operation for MethodLookupCache
423 friend class MethodLookupCache;
424 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
425 public:
426 Method* lookup_method(Symbol* name, Symbol* signature) const {
427 return uncached_lookup_method(name, signature);
428 }
430 // array class with specific rank
431 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); }
433 // array class with this klass as element type
434 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); }
436 // These will return NULL instead of allocating on the heap:
437 // NB: these can block for a mutex, like other functions with TRAPS arg.
438 Klass* array_klass_or_null(int rank);
439 Klass* array_klass_or_null();
441 virtual oop protection_domain() const = 0;
443 oop class_loader() const;
445 virtual oop klass_holder() const { return class_loader(); }
447 protected:
448 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS);
449 virtual Klass* array_klass_impl(bool or_null, TRAPS);
451 public:
452 // CDS support - remove and restore oops from metadata. Oops are not shared.
453 virtual void remove_unshareable_info();
454 virtual void restore_unshareable_info(TRAPS);
456 protected:
457 // computes the subtype relationship
458 virtual bool compute_is_subtype_of(Klass* k);
459 public:
460 // subclass accessor (here for convenience; undefined for non-klass objects)
461 virtual bool is_leaf_class() const { fatal("not a class"); return false; }
462 public:
463 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
464 // These functions describe behavior for the oop not the KLASS.
466 // actual oop size of obj in memory
467 virtual int oop_size(oop obj) const = 0;
469 // Size of klass in word size.
470 virtual int size() const = 0;
471 #if INCLUDE_SERVICES
472 virtual void collect_statistics(KlassSizeStats *sz) const;
473 #endif
475 // Returns the Java name for a class (Resource allocated)
476 // For arrays, this returns the name of the element with a leading '['.
477 // For classes, this returns the name with the package separators
478 // turned into '.'s.
479 const char* external_name() const;
480 // Returns the name for a class (Resource allocated) as the class
481 // would appear in a signature.
482 // For arrays, this returns the name of the element with a leading '['.
483 // For classes, this returns the name with a leading 'L' and a trailing ';'
484 // and the package separators as '/'.
485 virtual const char* signature_name() const;
487 // garbage collection support
488 virtual void oop_follow_contents(oop obj) = 0;
489 virtual int oop_adjust_pointers(oop obj) = 0;
491 // Parallel Scavenge and Parallel Old
492 PARALLEL_GC_DECLS_PV
494 // type testing operations
495 protected:
496 virtual bool oop_is_instance_slow() const { return false; }
497 virtual bool oop_is_array_slow() const { return false; }
498 virtual bool oop_is_objArray_slow() const { return false; }
499 virtual bool oop_is_typeArray_slow() const { return false; }
500 public:
501 virtual bool oop_is_instanceMirror() const { return false; }
502 virtual bool oop_is_instanceRef() const { return false; }
504 // Fast non-virtual versions
505 #ifndef ASSERT
506 #define assert_same_query(xval, xcheck) xval
507 #else
508 private:
509 static bool assert_same_query(bool xval, bool xslow) {
510 assert(xval == xslow, "slow and fast queries agree");
511 return xval;
512 }
513 public:
514 #endif
515 inline bool oop_is_instance() const { return assert_same_query(
516 layout_helper_is_instance(layout_helper()),
517 oop_is_instance_slow()); }
518 inline bool oop_is_array() const { return assert_same_query(
519 layout_helper_is_array(layout_helper()),
520 oop_is_array_slow()); }
521 inline bool oop_is_objArray() const { return assert_same_query(
522 layout_helper_is_objArray(layout_helper()),
523 oop_is_objArray_slow()); }
524 inline bool oop_is_typeArray() const { return assert_same_query(
525 layout_helper_is_typeArray(layout_helper()),
526 oop_is_typeArray_slow()); }
527 #undef assert_same_query
529 // Access flags
530 AccessFlags access_flags() const { return _access_flags; }
531 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
533 bool is_public() const { return _access_flags.is_public(); }
534 bool is_final() const { return _access_flags.is_final(); }
535 bool is_interface() const { return _access_flags.is_interface(); }
536 bool is_abstract() const { return _access_flags.is_abstract(); }
537 bool is_super() const { return _access_flags.is_super(); }
538 bool is_synthetic() const { return _access_flags.is_synthetic(); }
539 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
540 bool has_finalizer() const { return _access_flags.has_finalizer(); }
541 bool has_final_method() const { return _access_flags.has_final_method(); }
542 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
543 void set_has_final_method() { _access_flags.set_has_final_method(); }
544 bool is_cloneable() const { return _access_flags.is_cloneable(); }
545 void set_is_cloneable() { _access_flags.set_is_cloneable(); }
546 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
547 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
548 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
549 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
551 // Biased locking support
552 // Note: the prototype header is always set up to be at least the
553 // prototype markOop. If biased locking is enabled it may further be
554 // biasable and have an epoch.
555 markOop prototype_header() const { return _prototype_header; }
556 // NOTE: once instances of this klass are floating around in the
557 // system, this header must only be updated at a safepoint.
558 // NOTE 2: currently we only ever set the prototype header to the
559 // biasable prototype for instanceKlasses. There is no technical
560 // reason why it could not be done for arrayKlasses aside from
561 // wanting to reduce the initial scope of this optimization. There
562 // are potential problems in setting the bias pattern for
563 // JVM-internal oops.
564 inline void set_prototype_header(markOop header);
565 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
567 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
568 // Atomically increments biased_lock_revocation_count and returns updated value
569 int atomic_incr_biased_lock_revocation_count();
570 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
571 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
572 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
574 TRACE_DEFINE_KLASS_METHODS;
576 // garbage collection support
577 virtual void oops_do(OopClosure* cl);
579 // Iff the class loader (or mirror for anonymous classes) is alive the
580 // Klass is considered alive.
581 // The is_alive closure passed in depends on the Garbage Collector used.
582 bool is_loader_alive(BoolObjectClosure* is_alive);
584 static void clean_weak_klass_links(BoolObjectClosure* is_alive);
586 // Prefetch within oop iterators. This is a macro because we
587 // can't guarantee that the compiler will inline it. In 64-bit
588 // it generally doesn't. Signature is
589 //
590 // static void prefetch_beyond(oop* const start,
591 // oop* const end,
592 // const intx foffset,
593 // const Prefetch::style pstyle);
594 #define prefetch_beyond(start, end, foffset, pstyle) { \
595 const intx foffset_ = (foffset); \
596 const Prefetch::style pstyle_ = (pstyle); \
597 assert(foffset_ > 0, "prefetch beyond, not behind"); \
598 if (pstyle_ != Prefetch::do_none) { \
599 oop* ref = (start); \
600 if (ref < (end)) { \
601 switch (pstyle_) { \
602 case Prefetch::do_read: \
603 Prefetch::read(*ref, foffset_); \
604 break; \
605 case Prefetch::do_write: \
606 Prefetch::write(*ref, foffset_); \
607 break; \
608 default: \
609 ShouldNotReachHere(); \
610 break; \
611 } \
612 } \
613 } \
614 }
616 // iterators
617 virtual int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) = 0;
618 virtual int oop_oop_iterate_v(oop obj, ExtendedOopClosure* blk) {
619 return oop_oop_iterate(obj, blk);
620 }
622 #if INCLUDE_ALL_GCS
623 // In case we don't have a specialized backward scanner use forward
624 // iteration.
625 virtual int oop_oop_iterate_backwards_v(oop obj, ExtendedOopClosure* blk) {
626 return oop_oop_iterate_v(obj, blk);
627 }
628 #endif // INCLUDE_ALL_GCS
630 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
631 // (I don't see why the _m should be required, but without it the Solaris
632 // C++ gives warning messages about overridings of the "oop_oop_iterate"
633 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */
634 virtual int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) = 0;
635 virtual int oop_oop_iterate_v_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
636 return oop_oop_iterate_m(obj, blk, mr);
637 }
639 // Versions of the above iterators specialized to particular subtypes
640 // of OopClosure, to avoid closure virtual calls.
641 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
642 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \
643 /* Default implementation reverts to general version. */ \
644 return oop_oop_iterate(obj, blk); \
645 } \
646 \
647 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
648 (I don't see why the _m should be required, but without it the Solaris \
649 C++ gives warning messages about overridings of the "oop_oop_iterate" \
650 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \
651 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \
652 OopClosureType* blk, \
653 MemRegion mr) { \
654 return oop_oop_iterate_m(obj, blk, mr); \
655 }
657 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
658 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL)
660 #if INCLUDE_ALL_GCS
661 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
662 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \
663 OopClosureType* blk) { \
664 /* Default implementation reverts to general version. */ \
665 return oop_oop_iterate_backwards_v(obj, blk); \
666 }
668 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
669 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL)
670 #endif // INCLUDE_ALL_GCS
672 virtual void array_klasses_do(void f(Klass* k)) {}
674 // Return self, except for abstract classes with exactly 1
675 // implementor. Then return the 1 concrete implementation.
676 Klass *up_cast_abstract();
678 // klass name
679 Symbol* name() const { return _name; }
680 void set_name(Symbol* n);
682 public:
683 // jvm support
684 virtual jint compute_modifier_flags(TRAPS) const;
686 // JVMTI support
687 virtual jint jvmti_class_status() const;
689 // Printing
690 virtual void print_on(outputStream* st) const;
692 virtual void oop_print_value_on(oop obj, outputStream* st);
693 virtual void oop_print_on (oop obj, outputStream* st);
695 virtual const char* internal_name() const = 0;
697 // Verification
698 virtual void verify_on(outputStream* st);
699 void verify() { verify_on(tty); }
701 #ifndef PRODUCT
702 bool verify_vtable_index(int index);
703 bool verify_itable_index(int index);
704 #endif
706 virtual void oop_verify_on(oop obj, outputStream* st);
708 static bool is_null(narrowKlass obj);
709 static bool is_null(Klass* obj);
711 // klass encoding for klass pointer in objects.
712 static narrowKlass encode_klass_not_null(Klass* v);
713 static narrowKlass encode_klass(Klass* v);
715 static Klass* decode_klass_not_null(narrowKlass v);
716 static Klass* decode_klass(narrowKlass v);
718 private:
719 // barriers used by klass_oop_store
720 void klass_update_barrier_set(oop v);
721 void klass_update_barrier_set_pre(void* p, oop v);
722 };
724 #endif // SHARE_VM_OOPS_KLASS_HPP