51 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
52
53 // Forward declarations.
54 template <class T> class Array;
55 template <class T> class GrowableArray;
56 class ClassLoaderData;
57 class fieldDescriptor;
58 class klassVtable;
59 class ModuleEntry;
60 class PackageEntry;
61 class vtableEntry;
62
63 class Klass : public Metadata {
64
65 friend class VMStructs;
66 friend class JVMCIVMStructs;
67 public:
68 // Klass Kinds for all subclasses of Klass
69 enum KlassKind : u2 {
70 InstanceKlassKind,
71 InstanceRefKlassKind,
72 InstanceMirrorKlassKind,
73 InstanceClassLoaderKlassKind,
74 InstanceStackChunkKlassKind,
75 TypeArrayKlassKind,
76 ObjArrayKlassKind,
77 UnknownKlassKind
78 };
79
80 static const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
81 protected:
82
83 // If you add a new field that points to any metaspace object, you
84 // must add this field to Klass::metaspace_pointers_do().
85
86 // note: put frequently-used fields together at start of klass structure
87 // for better cache behavior (may not make much of a difference but sure won't hurt)
88 enum { _primary_super_limit = 8 };
89
90 // The "layout helper" is a combined descriptor of object layout.
91 // For klasses which are neither instance nor array, the value is zero.
92 //
93 // For instances, layout helper is a positive number, the instance size.
94 // This size is already passed through align_object_size and scaled to bytes.
95 // The low order bit is set if instances of this class cannot be
96 // allocated using the fastpath.
97 //
98 // For arrays, layout helper is a negative number, containing four
99 // distinct bytes, as follows:
100 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
101 // where:
102 // tag is 0x80 if the elements are oops, 0xC0 if non-oops
103 // hsz is array header size in bytes (i.e., offset of first element)
104 // ebt is the BasicType of the elements
105 // esz is the element size in bytes
106 // This packed word is arranged so as to be quickly unpacked by the
107 // various fast paths that use the various subfields.
108 //
109 // The esz bits can be used directly by a SLL instruction, without masking.
110 //
111 // Note that the array-kind tag looks like 0x00 for instance klasses,
112 // since their length in bytes is always less than 24Mb.
113 //
114 // Final note: This comes first, immediately after C++ vtable,
115 // because it is frequently queried.
116 jint _layout_helper;
117
118 // Klass kind used to resolve the runtime type of the instance.
119 // - Used to implement devirtualized oop closure dispatching.
120 // - Various type checking in the JVM
121 const KlassKind _kind;
122
188 _has_aot_initialized_mirror = 1 << 6,
189 // If this class has been aot-inititalized, do we need to call its runtimeSetup()
190 // method during the production run?
191 _is_runtime_setup_required = 1 << 7,
192 };
193 #endif
194
195 int _vtable_len; // vtable length. This field may be read very often when we
196 // have lots of itable dispatches (e.g., lambdas and streams).
197 // Keep it away from the beginning of a Klass to avoid cacheline
198 // contention that may happen when a nearby object is modified.
199
200 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
201
202 public:
203
204 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
205
206 protected:
207
208 Klass(KlassKind kind);
209 Klass();
210
211 public:
212 int kind() { return _kind; }
213
214 enum class DefaultsLookupMode { find, skip };
215 enum class OverpassLookupMode { find, skip };
216 enum class StaticLookupMode { find, skip };
217 enum class PrivateLookupMode { find, skip };
218
219 virtual bool is_klass() const { return true; }
220
221 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
222 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
223 // If this is not what your code expects, you're probably looking for Klass::java_super().
224 Klass* super() const { return _super; }
225 void set_super(Klass* k) { _super = k; }
226
227 // initializes _super link, _primary_supers & _secondary_supers arrays
228 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
444 static ByteSize layout_helper_offset() { return byte_offset_of(Klass, _layout_helper); }
445 static ByteSize access_flags_offset() { return byte_offset_of(Klass, _access_flags); }
446 #if INCLUDE_JVMCI
447 static ByteSize subklass_offset() { return byte_offset_of(Klass, _subklass); }
448 static ByteSize next_sibling_offset() { return byte_offset_of(Klass, _next_sibling); }
449 #endif
450 static ByteSize secondary_supers_bitmap_offset()
451 { return byte_offset_of(Klass, _secondary_supers_bitmap); }
452 static ByteSize hash_slot_offset() { return byte_offset_of(Klass, _hash_slot); }
453 static ByteSize misc_flags_offset() { return byte_offset_of(Klass, _misc_flags._flags); }
454
455 // Unpacking layout_helper:
456 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
457 static const int _lh_instance_slow_path_bit = 0x01;
458 static const int _lh_log2_element_size_shift = BitsPerByte*0;
459 static const int _lh_log2_element_size_mask = BitsPerLong-1;
460 static const int _lh_element_type_shift = BitsPerByte*1;
461 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
462 static const int _lh_header_size_shift = BitsPerByte*2;
463 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
464 static const int _lh_array_tag_bits = 2;
465 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
466 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30
467
468 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
469
470 static int layout_helper_size_in_bytes(jint lh) {
471 assert(lh > (jint)_lh_neutral_value, "must be instance");
472 return (int) lh & ~_lh_instance_slow_path_bit;
473 }
474 static bool layout_helper_needs_slow_path(jint lh) {
475 assert(lh > (jint)_lh_neutral_value, "must be instance");
476 return (lh & _lh_instance_slow_path_bit) != 0;
477 }
478 static bool layout_helper_is_instance(jint lh) {
479 return (jint)lh > (jint)_lh_neutral_value;
480 }
481 static bool layout_helper_is_array(jint lh) {
482 return (jint)lh < (jint)_lh_neutral_value;
483 }
484 static bool layout_helper_is_typeArray(jint lh) {
485 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
486 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
487 }
488 static bool layout_helper_is_objArray(jint lh) {
489 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
490 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
491 }
492 static int layout_helper_header_size(jint lh) {
493 assert(lh < (jint)_lh_neutral_value, "must be array");
494 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
495 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
496 return hsize;
497 }
498 static BasicType layout_helper_element_type(jint lh) {
499 assert(lh < (jint)_lh_neutral_value, "must be array");
500 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
501 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
502 return (BasicType) btvalue;
503 }
504
505 // Want a pattern to quickly diff against layout header in register
506 // find something less clever!
507 static int layout_helper_boolean_diffbit() {
508 jint zlh = array_layout_helper(T_BOOLEAN);
509 jint blh = array_layout_helper(T_BYTE);
510 assert(zlh != blh, "array layout helpers must differ");
511 int diffbit = 1;
512 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
513 diffbit <<= 1;
514 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
515 }
516 return diffbit;
517 }
518
519 static int layout_helper_log2_element_size(jint lh) {
520 assert(lh < (jint)_lh_neutral_value, "must be array");
521 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
522 assert(l2esz <= LogBytesPerLong,
523 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
524 return l2esz;
525 }
526 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
527 return (tag << _lh_array_tag_shift)
528 | (hsize << _lh_header_size_shift)
529 | ((int)etype << _lh_element_type_shift)
530 | (log2_esize << _lh_log2_element_size_shift);
531 }
532 static jint instance_layout_helper(jint size, bool slow_path_flag) {
533 return (size << LogBytesPerWord)
534 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
535 }
536 static int layout_helper_to_size_helper(jint lh) {
537 assert(lh > (jint)_lh_neutral_value, "must be instance");
538 // Note that the following expression discards _lh_instance_slow_path_bit.
539 return lh >> LogBytesPerWord;
540 }
541 // Out-of-line version computes everything based on the etype:
542 static jint array_layout_helper(BasicType etype);
543
544 // What is the maximum number of primary superclasses any klass can have?
545 static juint primary_super_limit() { return _primary_super_limit; }
546
547 // vtables
651 // Returns the name for a class (Resource allocated) as the class
652 // would appear in a signature.
653 // For arrays, this returns the name of the element with a leading '['.
654 // For classes, this returns the name with a leading 'L' and a trailing ';'
655 // and the package separators as '/'.
656 virtual const char* signature_name() const;
657
658 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
659 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
660
661 // Returns "interface", "abstract class" or "class".
662 const char* external_kind() const;
663
664 // type testing operations
665 #ifdef ASSERT
666 protected:
667 virtual bool is_instance_klass_slow() const { return false; }
668 virtual bool is_array_klass_slow() const { return false; }
669 virtual bool is_objArray_klass_slow() const { return false; }
670 virtual bool is_typeArray_klass_slow() const { return false; }
671 #endif // ASSERT
672 public:
673
674 // Fast non-virtual versions
675 #ifndef ASSERT
676 #define assert_same_query(xval, xcheck) xval
677 #else
678 private:
679 static bool assert_same_query(bool xval, bool xslow) {
680 assert(xval == xslow, "slow and fast queries agree");
681 return xval;
682 }
683 public:
684 #endif
685
686 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); }
687 // Other is anything that is not one of the more specialized kinds of InstanceKlass.
688 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; }
689 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
690 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
691 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
692 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
693 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; }
694 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
695 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
696 #undef assert_same_query
697
698 // Access flags
699 AccessFlags access_flags() const { return _access_flags; }
700 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
701
702 bool is_public() const { return _access_flags.is_public(); }
703 bool is_final() const { return _access_flags.is_final(); }
704 bool is_interface() const { return _access_flags.is_interface(); }
705 bool is_abstract() const { return _access_flags.is_abstract(); }
706 bool is_super() const { return _access_flags.is_super(); }
707 bool is_synthetic() const { return _access_flags.is_synthetic(); }
708 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
709 bool has_finalizer() const { return _misc_flags.has_finalizer(); }
710 void set_has_finalizer() { _misc_flags.set_has_finalizer(true); }
711 bool is_hidden() const { return _misc_flags.is_hidden_class(); }
712 void set_is_hidden() { _misc_flags.set_is_hidden_class(true); }
713 bool is_value_based() const { return _misc_flags.is_value_based_class(); }
714 void set_is_value_based() { _misc_flags.set_is_value_based_class(true); }
715
716 klass_flags_t misc_flags() const { return _misc_flags.value(); }
717
718 inline bool is_non_strong_hidden() const;
719
720 bool is_cloneable() const;
721 void set_is_cloneable();
722
723 inline markWord prototype_header() const;
724 inline void set_prototype_header(markWord header);
725 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
726
727 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
728
729 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
730 virtual MetaspaceObj::Type type() const { return ClassType; }
731
732 inline bool is_loader_alive() const;
733
734 void clean_subklass();
735
736 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
737 static void clean_subklass_tree() {
738 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
739 }
740
741 // Return self, except for abstract classes with exactly 1
742 // implementor. Then return the 1 concrete implementation.
743 Klass *up_cast_abstract();
744
745 // klass name
|
51 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
52
53 // Forward declarations.
54 template <class T> class Array;
55 template <class T> class GrowableArray;
56 class ClassLoaderData;
57 class fieldDescriptor;
58 class klassVtable;
59 class ModuleEntry;
60 class PackageEntry;
61 class vtableEntry;
62
63 class Klass : public Metadata {
64
65 friend class VMStructs;
66 friend class JVMCIVMStructs;
67 public:
68 // Klass Kinds for all subclasses of Klass
69 enum KlassKind : u2 {
70 InstanceKlassKind,
71 InlineKlassKind,
72 InstanceRefKlassKind,
73 InstanceMirrorKlassKind,
74 InstanceClassLoaderKlassKind,
75 InstanceStackChunkKlassKind,
76 TypeArrayKlassKind,
77 FlatArrayKlassKind,
78 ObjArrayKlassKind,
79 UnknownKlassKind
80 };
81
82 static const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
83 protected:
84
85 // If you add a new field that points to any metaspace object, you
86 // must add this field to Klass::metaspace_pointers_do().
87
88 // note: put frequently-used fields together at start of klass structure
89 // for better cache behavior (may not make much of a difference but sure won't hurt)
90 enum { _primary_super_limit = 8 };
91
92 // The "layout helper" is a combined descriptor of object layout.
93 // For klasses which are neither instance nor array, the value is zero.
94 //
95 // For instances, layout helper is a positive number, the instance size.
96 // This size is already passed through align_object_size and scaled to bytes.
97 // The low order bit is set if instances of this class cannot be
98 // allocated using the fastpath.
99 //
100 // For arrays, layout helper is a negative number, containing four
101 // distinct bytes, as follows:
102 // MSB:[tag, hsz, ebt, log2(esz)]:LSB
103 // where:
104 // tag is 0x80 if the elements are oops, 0xC0 if non-oops, 0xA0 if value types
105 // hsz is array header size in bytes (i.e., offset of first element)
106 // ebt is the BasicType of the elements
107 // esz is the element size in bytes
108 // This packed word is arranged so as to be quickly unpacked by the
109 // various fast paths that use the various subfields.
110 //
111 // The esz bits can be used directly by a SLL instruction, without masking.
112 //
113 // Note that the array-kind tag looks like 0x00 for instance klasses,
114 // since their length in bytes is always less than 24Mb.
115 //
116 // Final note: This comes first, immediately after C++ vtable,
117 // because it is frequently queried.
118 jint _layout_helper;
119
120 // Klass kind used to resolve the runtime type of the instance.
121 // - Used to implement devirtualized oop closure dispatching.
122 // - Various type checking in the JVM
123 const KlassKind _kind;
124
190 _has_aot_initialized_mirror = 1 << 6,
191 // If this class has been aot-inititalized, do we need to call its runtimeSetup()
192 // method during the production run?
193 _is_runtime_setup_required = 1 << 7,
194 };
195 #endif
196
197 int _vtable_len; // vtable length. This field may be read very often when we
198 // have lots of itable dispatches (e.g., lambdas and streams).
199 // Keep it away from the beginning of a Klass to avoid cacheline
200 // contention that may happen when a nearby object is modified.
201
202 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
203
204 public:
205
206 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
207
208 protected:
209
210 Klass(KlassKind kind, markWord prototype_header = markWord::prototype());
211 Klass();
212
213 public:
214 int kind() { return _kind; }
215
216 enum class DefaultsLookupMode { find, skip };
217 enum class OverpassLookupMode { find, skip };
218 enum class StaticLookupMode { find, skip };
219 enum class PrivateLookupMode { find, skip };
220
221 virtual bool is_klass() const { return true; }
222
223 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used
224 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;"
225 // If this is not what your code expects, you're probably looking for Klass::java_super().
226 Klass* super() const { return _super; }
227 void set_super(Klass* k) { _super = k; }
228
229 // initializes _super link, _primary_supers & _secondary_supers arrays
230 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS);
446 static ByteSize layout_helper_offset() { return byte_offset_of(Klass, _layout_helper); }
447 static ByteSize access_flags_offset() { return byte_offset_of(Klass, _access_flags); }
448 #if INCLUDE_JVMCI
449 static ByteSize subklass_offset() { return byte_offset_of(Klass, _subklass); }
450 static ByteSize next_sibling_offset() { return byte_offset_of(Klass, _next_sibling); }
451 #endif
452 static ByteSize secondary_supers_bitmap_offset()
453 { return byte_offset_of(Klass, _secondary_supers_bitmap); }
454 static ByteSize hash_slot_offset() { return byte_offset_of(Klass, _hash_slot); }
455 static ByteSize misc_flags_offset() { return byte_offset_of(Klass, _misc_flags._flags); }
456
457 // Unpacking layout_helper:
458 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
459 static const int _lh_instance_slow_path_bit = 0x01;
460 static const int _lh_log2_element_size_shift = BitsPerByte*0;
461 static const int _lh_log2_element_size_mask = BitsPerLong-1;
462 static const int _lh_element_type_shift = BitsPerByte*1;
463 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
464 static const int _lh_header_size_shift = BitsPerByte*2;
465 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
466 static const int _lh_array_tag_bits = 3;
467 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
468
469 static const unsigned int _lh_array_tag_type_value = 0Xfffffffc;
470 static const unsigned int _lh_array_tag_vt_value = 0Xfffffffd;
471 static const unsigned int _lh_array_tag_obj_value = 0Xfffffffe;
472
473 // null-free array flag bit under the array tag bits, shift one more to get array tag value
474 static const int _lh_null_free_shift = _lh_array_tag_shift - 1;
475 static const int _lh_null_free_mask = 1;
476
477 static const jint _lh_array_tag_flat_value_bit_inplace = (jint) (1 << _lh_array_tag_shift);
478
479 static int layout_helper_size_in_bytes(jint lh) {
480 assert(lh > (jint)_lh_neutral_value, "must be instance");
481 return (int) lh & ~_lh_instance_slow_path_bit;
482 }
483 static bool layout_helper_needs_slow_path(jint lh) {
484 assert(lh > (jint)_lh_neutral_value, "must be instance");
485 return (lh & _lh_instance_slow_path_bit) != 0;
486 }
487 static bool layout_helper_is_instance(jint lh) {
488 return (jint)lh > (jint)_lh_neutral_value;
489 }
490 static bool layout_helper_is_array(jint lh) {
491 return (jint)lh < (jint)_lh_neutral_value;
492 }
493 static bool layout_helper_is_typeArray(jint lh) {
494 return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift);
495 }
496 static bool layout_helper_is_objArray(jint lh) {
497 return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift);
498 }
499 static bool layout_helper_is_flatArray(jint lh) {
500 return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift);
501 }
502 static bool layout_helper_is_null_free(jint lh) {
503 assert(layout_helper_is_flatArray(lh) || layout_helper_is_objArray(lh), "must be array of inline types");
504 return ((lh >> _lh_null_free_shift) & _lh_null_free_mask);
505 }
506 static jint layout_helper_set_null_free(jint lh) {
507 lh |= (_lh_null_free_mask << _lh_null_free_shift);
508 assert(layout_helper_is_null_free(lh), "Bad encoding");
509 return lh;
510 }
511 static int layout_helper_header_size(jint lh) {
512 assert(lh < (jint)_lh_neutral_value, "must be array");
513 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
514 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
515 return hsize;
516 }
517 static BasicType layout_helper_element_type(jint lh) {
518 assert(lh < (jint)_lh_neutral_value, "must be array");
519 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
520 assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_FLAT_ELEMENT, "sanity");
521 return (BasicType) btvalue;
522 }
523
524 // Want a pattern to quickly diff against layout header in register
525 // find something less clever!
526 static int layout_helper_boolean_diffbit() {
527 jint zlh = array_layout_helper(T_BOOLEAN);
528 jint blh = array_layout_helper(T_BYTE);
529 assert(zlh != blh, "array layout helpers must differ");
530 int diffbit = 1;
531 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
532 diffbit <<= 1;
533 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
534 }
535 return diffbit;
536 }
537
538 static int layout_helper_log2_element_size(jint lh) {
539 assert(lh < (jint)_lh_neutral_value, "must be array");
540 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
541 assert(layout_helper_element_type(lh) == T_FLAT_ELEMENT || l2esz <= LogBytesPerLong,
542 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
543 return l2esz;
544 }
545 static jint array_layout_helper(jint tag, bool null_free, int hsize, BasicType etype, int log2_esize) {
546 return (tag << _lh_array_tag_shift)
547 | ((null_free ? 1 : 0) << _lh_null_free_shift)
548 | (hsize << _lh_header_size_shift)
549 | ((int)etype << _lh_element_type_shift)
550 | (log2_esize << _lh_log2_element_size_shift);
551 }
552 static jint instance_layout_helper(jint size, bool slow_path_flag) {
553 return (size << LogBytesPerWord)
554 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
555 }
556 static int layout_helper_to_size_helper(jint lh) {
557 assert(lh > (jint)_lh_neutral_value, "must be instance");
558 // Note that the following expression discards _lh_instance_slow_path_bit.
559 return lh >> LogBytesPerWord;
560 }
561 // Out-of-line version computes everything based on the etype:
562 static jint array_layout_helper(BasicType etype);
563
564 // What is the maximum number of primary superclasses any klass can have?
565 static juint primary_super_limit() { return _primary_super_limit; }
566
567 // vtables
671 // Returns the name for a class (Resource allocated) as the class
672 // would appear in a signature.
673 // For arrays, this returns the name of the element with a leading '['.
674 // For classes, this returns the name with a leading 'L' and a trailing ';'
675 // and the package separators as '/'.
676 virtual const char* signature_name() const;
677
678 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
679 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
680
681 // Returns "interface", "abstract class" or "class".
682 const char* external_kind() const;
683
684 // type testing operations
685 #ifdef ASSERT
686 protected:
687 virtual bool is_instance_klass_slow() const { return false; }
688 virtual bool is_array_klass_slow() const { return false; }
689 virtual bool is_objArray_klass_slow() const { return false; }
690 virtual bool is_typeArray_klass_slow() const { return false; }
691 virtual bool is_flatArray_klass_slow() const { return false; }
692 #endif // ASSERT
693 // current implementation uses this method even in non debug builds
694 virtual bool is_inline_klass_slow() const { return false; }
695 public:
696
697 // Fast non-virtual versions
698 #ifndef ASSERT
699 #define assert_same_query(xval, xcheck) xval
700 #else
701 private:
702 static bool assert_same_query(bool xval, bool xslow) {
703 assert(xval == xslow, "slow and fast queries agree");
704 return xval;
705 }
706 public:
707 #endif
708
709 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); }
710 bool is_inline_klass() const { return assert_same_query(_kind == InlineKlassKind, is_inline_klass_slow()); }
711 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
712 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
713 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
714 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
715 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; }
716 bool is_flatArray_klass() const { return assert_same_query( _kind == FlatArrayKlassKind, is_flatArray_klass_slow()); }
717 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
718 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
719 #undef assert_same_query
720
721 inline bool is_null_free_array_klass() const { return !is_typeArray_klass() && layout_helper_is_null_free(layout_helper()); }
722
723 // Access flags
724 AccessFlags access_flags() const { return _access_flags; }
725 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
726
727 bool is_public() const { return _access_flags.is_public(); }
728 bool is_final() const { return _access_flags.is_final(); }
729 bool is_interface() const { return _access_flags.is_interface(); }
730 bool is_abstract() const { return _access_flags.is_abstract(); }
731 bool is_synthetic() const { return _access_flags.is_synthetic(); }
732 bool is_identity_class() const { return _access_flags.is_identity_class(); }
733 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
734 bool has_finalizer() const { return _misc_flags.has_finalizer(); }
735 void set_has_finalizer() { _misc_flags.set_has_finalizer(true); }
736 bool is_hidden() const { return _misc_flags.is_hidden_class(); }
737 void set_is_hidden() { _misc_flags.set_is_hidden_class(true); }
738 bool is_value_based() const { return _misc_flags.is_value_based_class(); }
739 void set_is_value_based() { _misc_flags.set_is_value_based_class(true); }
740
741 klass_flags_t misc_flags() const { return _misc_flags.value(); }
742
743 inline bool is_non_strong_hidden() const;
744
745 bool is_cloneable() const;
746 void set_is_cloneable();
747
748 static inline markWord make_prototype_header(const Klass* kls, markWord prototype = markWord::prototype());
749 inline markWord prototype_header() const;
750 inline void set_prototype_header(markWord header);
751 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
752 static inline markWord default_prototype_header(Klass* k);
753
754 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
755
756 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
757 virtual MetaspaceObj::Type type() const { return ClassType; }
758
759 inline bool is_loader_alive() const;
760
761 void clean_subklass();
762
763 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
764 static void clean_subklass_tree() {
765 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
766 }
767
768 // Return self, except for abstract classes with exactly 1
769 // implementor. Then return the 1 concrete implementation.
770 Klass *up_cast_abstract();
771
772 // klass name
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