23 */
24
25 #ifndef SHARE_OOPS_KLASS_HPP
26 #define SHARE_OOPS_KLASS_HPP
27
28 #include "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/markWord.hpp"
31 #include "oops/metadata.hpp"
32 #include "oops/oop.hpp"
33 #include "oops/oopHandle.hpp"
34 #include "utilities/accessFlags.hpp"
35 #include "utilities/macros.hpp"
36 #if INCLUDE_JFR
37 #include "jfr/support/jfrTraceIdExtension.hpp"
38 #endif
39
40 // Klass Kinds for all subclasses of Klass
41 enum KlassKind {
42 InstanceKlassKind,
43 InstanceRefKlassKind,
44 InstanceMirrorKlassKind,
45 InstanceClassLoaderKlassKind,
46 InstanceStackChunkKlassKind,
47 TypeArrayKlassKind,
48 ObjArrayKlassKind
49 };
50
51 const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
52
53 //
54 // A Klass provides:
55 // 1: language level class object (method dictionary etc.)
56 // 2: provide vm dispatch behavior for the object
57 // Both functions are combined into one C++ class.
58
59 // One reason for the oop/klass dichotomy in the implementation is
60 // that we don't want a C++ vtbl pointer in every object. Thus,
61 // normal oops don't have any virtual functions. Instead, they
62 // forward all "virtual" functions to their klass, which does have
63 // a vtbl and does the C++ dispatch depending on the object's
64 // actual type. (See oop.inline.hpp for some of the forwarding code.)
65 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
66
67 // Forward declarations.
82 protected:
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
148 // First subclass (NULL if none); _subklass->next_sibling() is next one
149 Klass* volatile _subklass;
150 // Sibling link (or NULL); links all subklasses of a klass
151 Klass* volatile _next_sibling;
152
153 // All klasses loaded by a class loader are chained through these links
154 Klass* _next_link;
155
156 // The VM's representation of the ClassLoader used to load this class.
157 // Provide access the corresponding instance java.lang.ClassLoader.
158 ClassLoaderData* _class_loader_data;
159
160 int _vtable_len; // vtable length. This field may be read very often when we
161 // have lots of itable dispatches (e.g., lambdas and streams).
162 // Keep it away from the beginning of a Klass to avoid cacheline
163 // contention that may happen when a nearby object is modified.
164 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
165
166 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
167
168 private:
169 // This is an index into FileMapHeader::_shared_path_table[], to
170 // associate this class with the JAR file where it's loaded from during
171 // dump time. If a class is not loaded from the shared archive, this field is
172 // -1.
173 jshort _shared_class_path_index;
174
175 #if INCLUDE_CDS
176 // Various attributes for shared classes. Should be zero for a non-shared class.
177 u2 _shared_class_flags;
178 enum CDSSharedClassFlags {
179 _archived_lambda_proxy_is_available = 1 << 1,
180 _has_value_based_class_annotation = 1 << 2,
181 _verified_at_dump_time = 1 << 3,
182 _has_archived_enum_objs = 1 << 4,
183 // This class was not loaded from a classfile in the module image
184 // or classpath.
185 _is_generated_shared_class = 1 << 5
186 };
187 #endif
376 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
377 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
378 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
379 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
380 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
381 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
382 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
383 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
384 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
385 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
386
387 // Unpacking layout_helper:
388 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
389 static const int _lh_instance_slow_path_bit = 0x01;
390 static const int _lh_log2_element_size_shift = BitsPerByte*0;
391 static const int _lh_log2_element_size_mask = BitsPerLong-1;
392 static const int _lh_element_type_shift = BitsPerByte*1;
393 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
394 static const int _lh_header_size_shift = BitsPerByte*2;
395 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
396 static const int _lh_array_tag_bits = 2;
397 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
398 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30
399
400 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30
401
402 static int layout_helper_size_in_bytes(jint lh) {
403 assert(lh > (jint)_lh_neutral_value, "must be instance");
404 return (int) lh & ~_lh_instance_slow_path_bit;
405 }
406 static bool layout_helper_needs_slow_path(jint lh) {
407 assert(lh > (jint)_lh_neutral_value, "must be instance");
408 return (lh & _lh_instance_slow_path_bit) != 0;
409 }
410 static bool layout_helper_is_instance(jint lh) {
411 return (jint)lh > (jint)_lh_neutral_value;
412 }
413 static bool layout_helper_is_array(jint lh) {
414 return (jint)lh < (jint)_lh_neutral_value;
415 }
416 static bool layout_helper_is_typeArray(jint lh) {
417 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
418 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
419 }
420 static bool layout_helper_is_objArray(jint lh) {
421 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
422 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
423 }
424 static int layout_helper_header_size(jint lh) {
425 assert(lh < (jint)_lh_neutral_value, "must be array");
426 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
427 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
428 return hsize;
429 }
430 static BasicType layout_helper_element_type(jint lh) {
431 assert(lh < (jint)_lh_neutral_value, "must be array");
432 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
433 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
434 return (BasicType) btvalue;
435 }
436
437 // Want a pattern to quickly diff against layout header in register
438 // find something less clever!
439 static int layout_helper_boolean_diffbit() {
440 jint zlh = array_layout_helper(T_BOOLEAN);
441 jint blh = array_layout_helper(T_BYTE);
442 assert(zlh != blh, "array layout helpers must differ");
443 int diffbit = 1;
444 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
445 diffbit <<= 1;
446 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
447 }
448 return diffbit;
449 }
450
451 static int layout_helper_log2_element_size(jint lh) {
452 assert(lh < (jint)_lh_neutral_value, "must be array");
453 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
454 assert(l2esz <= LogBytesPerLong,
455 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
456 return l2esz;
457 }
458 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
459 return (tag << _lh_array_tag_shift)
460 | (hsize << _lh_header_size_shift)
461 | ((int)etype << _lh_element_type_shift)
462 | (log2_esize << _lh_log2_element_size_shift);
463 }
464 static jint instance_layout_helper(jint size, bool slow_path_flag) {
465 return (size << LogBytesPerWord)
466 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
467 }
468 static int layout_helper_to_size_helper(jint lh) {
469 assert(lh > (jint)_lh_neutral_value, "must be instance");
470 // Note that the following expression discards _lh_instance_slow_path_bit.
471 return lh >> LogBytesPerWord;
472 }
473 // Out-of-line version computes everything based on the etype:
474 static jint array_layout_helper(BasicType etype);
475
476 // What is the maximum number of primary superclasses any klass can have?
477 static juint primary_super_limit() { return _primary_super_limit; }
478
479 // vtables
592 // Returns the name for a class (Resource allocated) as the class
593 // would appear in a signature.
594 // For arrays, this returns the name of the element with a leading '['.
595 // For classes, this returns the name with a leading 'L' and a trailing ';'
596 // and the package separators as '/'.
597 virtual const char* signature_name() const;
598
599 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
600 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
601
602 // Returns "interface", "abstract class" or "class".
603 const char* external_kind() const;
604
605 // type testing operations
606 #ifdef ASSERT
607 protected:
608 virtual bool is_instance_klass_slow() const { return false; }
609 virtual bool is_array_klass_slow() const { return false; }
610 virtual bool is_objArray_klass_slow() const { return false; }
611 virtual bool is_typeArray_klass_slow() const { return false; }
612 #endif // ASSERT
613 public:
614
615 // Fast non-virtual versions
616 #ifndef ASSERT
617 #define assert_same_query(xval, xcheck) xval
618 #else
619 private:
620 static bool assert_same_query(bool xval, bool xslow) {
621 assert(xval == xslow, "slow and fast queries agree");
622 return xval;
623 }
624 public:
625 #endif
626
627 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); }
628 // Other is anything that is not one of the more specialized kinds of InstanceKlass.
629 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; }
630 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
631 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
632 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
633 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
634 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; }
635 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
636 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
637 #undef assert_same_query
638
639 // Access flags
640 AccessFlags access_flags() const { return _access_flags; }
641 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
642
643 bool is_public() const { return _access_flags.is_public(); }
644 bool is_final() const { return _access_flags.is_final(); }
645 bool is_interface() const { return _access_flags.is_interface(); }
646 bool is_abstract() const { return _access_flags.is_abstract(); }
647 bool is_super() const { return _access_flags.is_super(); }
648 bool is_synthetic() const { return _access_flags.is_synthetic(); }
649 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
650 bool has_finalizer() const { return _access_flags.has_finalizer(); }
651 bool has_final_method() const { return _access_flags.has_final_method(); }
652 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
653 void set_has_final_method() { _access_flags.set_has_final_method(); }
654 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
655 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
656 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
657 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
658 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
659 void set_is_shared() { _access_flags.set_is_shared_class(); }
660 bool is_hidden() const { return access_flags().is_hidden_class(); }
661 void set_is_hidden() { _access_flags.set_is_hidden_class(); }
662 bool is_value_based() { return _access_flags.is_value_based_class(); }
663 void set_is_value_based() { _access_flags.set_is_value_based_class(); }
664
665 inline bool is_non_strong_hidden() const;
666
667 bool is_cloneable() const;
668 void set_is_cloneable();
669
670 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
671
672 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
673 virtual MetaspaceObj::Type type() const { return ClassType; }
674
675 inline bool is_loader_alive() const;
676
677 void clean_subklass();
678
679 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
680 static void clean_subklass_tree() {
681 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
682 }
683
684 // Return self, except for abstract classes with exactly 1
685 // implementor. Then return the 1 concrete implementation.
686 Klass *up_cast_abstract();
687
688 // klass name
689 Symbol* name() const { return _name; }
|
23 */
24
25 #ifndef SHARE_OOPS_KLASS_HPP
26 #define SHARE_OOPS_KLASS_HPP
27
28 #include "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/markWord.hpp"
31 #include "oops/metadata.hpp"
32 #include "oops/oop.hpp"
33 #include "oops/oopHandle.hpp"
34 #include "utilities/accessFlags.hpp"
35 #include "utilities/macros.hpp"
36 #if INCLUDE_JFR
37 #include "jfr/support/jfrTraceIdExtension.hpp"
38 #endif
39
40 // Klass Kinds for all subclasses of Klass
41 enum KlassKind {
42 InstanceKlassKind,
43 InlineKlassKind,
44 InstanceRefKlassKind,
45 InstanceMirrorKlassKind,
46 InstanceClassLoaderKlassKind,
47 InstanceStackChunkKlassKind,
48 TypeArrayKlassKind,
49 FlatArrayKlassKind,
50 ObjArrayKlassKind
51 };
52
53 const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1;
54
55 //
56 // A Klass provides:
57 // 1: language level class object (method dictionary etc.)
58 // 2: provide vm dispatch behavior for the object
59 // Both functions are combined into one C++ class.
60
61 // One reason for the oop/klass dichotomy in the implementation is
62 // that we don't want a C++ vtbl pointer in every object. Thus,
63 // normal oops don't have any virtual functions. Instead, they
64 // forward all "virtual" functions to their klass, which does have
65 // a vtbl and does the C++ dispatch depending on the object's
66 // actual type. (See oop.inline.hpp for some of the forwarding code.)
67 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
68
69 // Forward declarations.
84 protected:
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
150 // First subclass (NULL if none); _subklass->next_sibling() is next one
151 Klass* volatile _subklass;
152 // Sibling link (or NULL); links all subklasses of a klass
153 Klass* volatile _next_sibling;
154
155 // All klasses loaded by a class loader are chained through these links
156 Klass* _next_link;
157
158 // The VM's representation of the ClassLoader used to load this class.
159 // Provide access the corresponding instance java.lang.ClassLoader.
160 ClassLoaderData* _class_loader_data;
161
162 int _vtable_len; // vtable length. This field may be read very often when we
163 // have lots of itable dispatches (e.g., lambdas and streams).
164 // Keep it away from the beginning of a Klass to avoid cacheline
165 // contention that may happen when a nearby object is modified.
166 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
167
168 JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
169
170 markWord _prototype_header; // inline type and inline array mark patterns
171 private:
172 // This is an index into FileMapHeader::_shared_path_table[], to
173 // associate this class with the JAR file where it's loaded from during
174 // dump time. If a class is not loaded from the shared archive, this field is
175 // -1.
176 jshort _shared_class_path_index;
177
178 #if INCLUDE_CDS
179 // Various attributes for shared classes. Should be zero for a non-shared class.
180 u2 _shared_class_flags;
181 enum CDSSharedClassFlags {
182 _archived_lambda_proxy_is_available = 1 << 1,
183 _has_value_based_class_annotation = 1 << 2,
184 _verified_at_dump_time = 1 << 3,
185 _has_archived_enum_objs = 1 << 4,
186 // This class was not loaded from a classfile in the module image
187 // or classpath.
188 _is_generated_shared_class = 1 << 5
189 };
190 #endif
379 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
380 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
381 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); }
382 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
383 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
384 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); }
385 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
386 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
387 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); }
388 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); }
389
390 // Unpacking layout_helper:
391 static const int _lh_neutral_value = 0; // neutral non-array non-instance value
392 static const int _lh_instance_slow_path_bit = 0x01;
393 static const int _lh_log2_element_size_shift = BitsPerByte*0;
394 static const int _lh_log2_element_size_mask = BitsPerLong-1;
395 static const int _lh_element_type_shift = BitsPerByte*1;
396 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask
397 static const int _lh_header_size_shift = BitsPerByte*2;
398 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask
399 static const int _lh_array_tag_bits = 3;
400 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits;
401
402 static const unsigned int _lh_array_tag_type_value = 0Xfffffffc;
403 static const unsigned int _lh_array_tag_vt_value = 0Xfffffffd;
404 static const unsigned int _lh_array_tag_obj_value = 0Xfffffffe;
405
406 // null-free array flag bit under the array tag bits, shift one more to get array tag value
407 static const int _lh_null_free_shift = _lh_array_tag_shift - 1;
408 static const int _lh_null_free_mask = 1;
409
410 static const jint _lh_array_tag_flat_value_bit_inplace = (jint) (1 << _lh_array_tag_shift);
411 static const jint _lh_null_free_array_bit_inplace = (jint) (_lh_null_free_mask << _lh_null_free_shift);
412
413 static int layout_helper_size_in_bytes(jint lh) {
414 assert(lh > (jint)_lh_neutral_value, "must be instance");
415 return (int) lh & ~_lh_instance_slow_path_bit;
416 }
417 static bool layout_helper_needs_slow_path(jint lh) {
418 assert(lh > (jint)_lh_neutral_value, "must be instance");
419 return (lh & _lh_instance_slow_path_bit) != 0;
420 }
421 static bool layout_helper_is_instance(jint lh) {
422 return (jint)lh > (jint)_lh_neutral_value;
423 }
424 static bool layout_helper_is_array(jint lh) {
425 return (jint)lh < (jint)_lh_neutral_value;
426 }
427 static bool layout_helper_is_typeArray(jint lh) {
428 return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift);
429 }
430 static bool layout_helper_is_objArray(jint lh) {
431 return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift);
432 }
433 static bool layout_helper_is_flatArray(jint lh) {
434 return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift);
435 }
436 static bool layout_helper_is_null_free(jint lh) {
437 assert(layout_helper_is_flatArray(lh) || layout_helper_is_objArray(lh), "must be array of inline types");
438 return ((lh >> _lh_null_free_shift) & _lh_null_free_mask);
439 }
440 static jint layout_helper_set_null_free(jint lh) {
441 lh |= (_lh_null_free_mask << _lh_null_free_shift);
442 assert(layout_helper_is_null_free(lh), "Bad encoding");
443 return lh;
444 }
445 static int layout_helper_header_size(jint lh) {
446 assert(lh < (jint)_lh_neutral_value, "must be array");
447 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
448 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
449 return hsize;
450 }
451 static BasicType layout_helper_element_type(jint lh) {
452 assert(lh < (jint)_lh_neutral_value, "must be array");
453 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
454 assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_PRIMITIVE_OBJECT, "sanity");
455 return (BasicType) btvalue;
456 }
457
458 // Want a pattern to quickly diff against layout header in register
459 // find something less clever!
460 static int layout_helper_boolean_diffbit() {
461 jint zlh = array_layout_helper(T_BOOLEAN);
462 jint blh = array_layout_helper(T_BYTE);
463 assert(zlh != blh, "array layout helpers must differ");
464 int diffbit = 1;
465 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
466 diffbit <<= 1;
467 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
468 }
469 return diffbit;
470 }
471
472 static int layout_helper_log2_element_size(jint lh) {
473 assert(lh < (jint)_lh_neutral_value, "must be array");
474 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
475 assert(layout_helper_element_type(lh) == T_PRIMITIVE_OBJECT || l2esz <= LogBytesPerLong,
476 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
477 return l2esz;
478 }
479 static jint array_layout_helper(jint tag, bool null_free, int hsize, BasicType etype, int log2_esize) {
480 return (tag << _lh_array_tag_shift)
481 | ((null_free ? 1 : 0) << _lh_null_free_shift)
482 | (hsize << _lh_header_size_shift)
483 | ((int)etype << _lh_element_type_shift)
484 | (log2_esize << _lh_log2_element_size_shift);
485 }
486 static jint instance_layout_helper(jint size, bool slow_path_flag) {
487 return (size << LogBytesPerWord)
488 | (slow_path_flag ? _lh_instance_slow_path_bit : 0);
489 }
490 static int layout_helper_to_size_helper(jint lh) {
491 assert(lh > (jint)_lh_neutral_value, "must be instance");
492 // Note that the following expression discards _lh_instance_slow_path_bit.
493 return lh >> LogBytesPerWord;
494 }
495 // Out-of-line version computes everything based on the etype:
496 static jint array_layout_helper(BasicType etype);
497
498 // What is the maximum number of primary superclasses any klass can have?
499 static juint primary_super_limit() { return _primary_super_limit; }
500
501 // vtables
614 // Returns the name for a class (Resource allocated) as the class
615 // would appear in a signature.
616 // For arrays, this returns the name of the element with a leading '['.
617 // For classes, this returns the name with a leading 'L' and a trailing ';'
618 // and the package separators as '/'.
619 virtual const char* signature_name() const;
620
621 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
622 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
623
624 // Returns "interface", "abstract class" or "class".
625 const char* external_kind() const;
626
627 // type testing operations
628 #ifdef ASSERT
629 protected:
630 virtual bool is_instance_klass_slow() const { return false; }
631 virtual bool is_array_klass_slow() const { return false; }
632 virtual bool is_objArray_klass_slow() const { return false; }
633 virtual bool is_typeArray_klass_slow() const { return false; }
634 virtual bool is_flatArray_klass_slow() const { return false; }
635 #endif // ASSERT
636 // current implementation uses this method even in non debug builds
637 virtual bool is_inline_klass_slow() const { return false; }
638 public:
639
640 // Fast non-virtual versions
641 #ifndef ASSERT
642 #define assert_same_query(xval, xcheck) xval
643 #else
644 private:
645 static bool assert_same_query(bool xval, bool xslow) {
646 assert(xval == xslow, "slow and fast queries agree");
647 return xval;
648 }
649 public:
650 #endif
651
652 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); }
653 bool is_inline_klass() const { return is_inline_klass_slow(); } //temporary hack
654 // Other is anything that is not one of the more specialized kinds of InstanceKlass.
655 bool is_other_instance_klass() const { return _kind <= InlineKlassKind; }
656 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; }
657 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; }
658 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; }
659 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); }
660 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; }
661 bool is_flatArray_klass() const { return assert_same_query( _kind == FlatArrayKlassKind, is_flatArray_klass_slow()); }
662 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); }
663 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); }
664 #undef assert_same_query
665
666 inline bool is_null_free_array_klass() const { return layout_helper_is_null_free(layout_helper()); }
667
668 // Access flags
669 AccessFlags access_flags() const { return _access_flags; }
670 void set_access_flags(AccessFlags flags) { _access_flags = flags; }
671
672 bool is_public() const { return _access_flags.is_public(); }
673 bool is_final() const { return _access_flags.is_final(); }
674 bool is_interface() const { return _access_flags.is_interface(); }
675 bool is_abstract() const { return _access_flags.is_abstract(); }
676 bool is_synthetic() const { return _access_flags.is_synthetic(); }
677 bool is_value_class() const { return _access_flags.is_value_class(); }
678 bool is_identity_class() const { return _access_flags.is_identity_class(); }
679 void set_is_synthetic() { _access_flags.set_is_synthetic(); }
680 bool has_finalizer() const { return _access_flags.has_finalizer(); }
681 bool has_final_method() const { return _access_flags.has_final_method(); }
682 void set_has_finalizer() { _access_flags.set_has_finalizer(); }
683 void set_has_final_method() { _access_flags.set_has_final_method(); }
684 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); }
685 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); }
686 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); }
687 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); }
688 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
689 void set_is_shared() { _access_flags.set_is_shared_class(); }
690 bool is_hidden() const { return access_flags().is_hidden_class(); }
691 void set_is_hidden() { _access_flags.set_is_hidden_class(); }
692 bool is_value_based() { return _access_flags.is_value_based_class(); }
693 void set_is_value_based() { _access_flags.set_is_value_based_class(); }
694
695 inline bool is_non_strong_hidden() const;
696
697 bool is_cloneable() const;
698 void set_is_cloneable();
699
700 // inline types and inline type array patterns
701 markWord prototype_header() const {
702 return _prototype_header;
703 }
704 static inline markWord default_prototype_header(Klass* k) {
705 return (k == NULL) ? markWord::prototype() : k->prototype_header();
706 }
707
708 inline void set_prototype_header(markWord header);
709 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
710
711 JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
712
713 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
714 virtual MetaspaceObj::Type type() const { return ClassType; }
715
716 inline bool is_loader_alive() const;
717
718 void clean_subklass();
719
720 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
721 static void clean_subklass_tree() {
722 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
723 }
724
725 // Return self, except for abstract classes with exactly 1
726 // implementor. Then return the 1 concrete implementation.
727 Klass *up_cast_abstract();
728
729 // klass name
730 Symbol* name() const { return _name; }
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