< prev index next >

src/hotspot/share/oops/klass.hpp

Print this page

 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 IDs for all subclasses of Klass
 41 enum KlassID {
 42   InstanceKlassID,
 43   InstanceRefKlassID,
 44   InstanceMirrorKlassID,
 45   InstanceClassLoaderKlassID,
 46   TypeArrayKlassID,

 47   ObjArrayKlassID
 48 };
 49 
 50 const uint KLASS_ID_COUNT = 6;
 51 
 52 //
 53 // A Klass provides:
 54 //  1: language level class object (method dictionary etc.)
 55 //  2: provide vm dispatch behavior for the object
 56 // Both functions are combined into one C++ class.
 57 
 58 // One reason for the oop/klass dichotomy in the implementation is
 59 // that we don't want a C++ vtbl pointer in every object.  Thus,
 60 // normal oops don't have any virtual functions.  Instead, they
 61 // forward all "virtual" functions to their klass, which does have
 62 // a vtbl and does the C++ dispatch depending on the object's
 63 // actual type.  (See oop.inline.hpp for some of the forwarding code.)
 64 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
 65 
 66 // Forward declarations.
 67 template <class T> class Array;
 68 template <class T> class GrowableArray;
 69 class ClassLoaderData;
 70 class fieldDescriptor;

 81  protected:
 82   // If you add a new field that points to any metaspace object, you
 83   // must add this field to Klass::metaspace_pointers_do().
 84 
 85   // note: put frequently-used fields together at start of klass structure
 86   // for better cache behavior (may not make much of a difference but sure won't hurt)
 87   enum { _primary_super_limit = 8 };
 88 
 89   // The "layout helper" is a combined descriptor of object layout.
 90   // For klasses which are neither instance nor array, the value is zero.
 91   //
 92   // For instances, layout helper is a positive number, the instance size.
 93   // This size is already passed through align_object_size and scaled to bytes.
 94   // The low order bit is set if instances of this class cannot be
 95   // allocated using the fastpath.
 96   //
 97   // For arrays, layout helper is a negative number, containing four
 98   // distinct bytes, as follows:
 99   //    MSB:[tag, hsz, ebt, log2(esz)]:LSB
100   // where:
101   //    tag is 0x80 if the elements are oops, 0xC0 if non-oops
102   //    hsz is array header size in bytes (i.e., offset of first element)
103   //    ebt is the BasicType of the elements
104   //    esz is the element size in bytes
105   // This packed word is arranged so as to be quickly unpacked by the
106   // various fast paths that use the various subfields.
107   //
108   // The esz bits can be used directly by a SLL instruction, without masking.
109   //
110   // Note that the array-kind tag looks like 0x00 for instance klasses,
111   // since their length in bytes is always less than 24Mb.
112   //
113   // Final note:  This comes first, immediately after C++ vtable,
114   // because it is frequently queried.
115   jint        _layout_helper;
116 
117   // Klass identifier used to implement devirtualized oop closure dispatching.
118   const KlassID _id;
119 
120   // vtable length
121   int _vtable_len;

142   OopHandle   _java_mirror;
143   // Superclass
144   Klass*      _super;
145   // First subclass (NULL if none); _subklass->next_sibling() is next one
146   Klass* volatile _subklass;
147   // Sibling link (or NULL); links all subklasses of a klass
148   Klass* volatile _next_sibling;
149 
150   // All klasses loaded by a class loader are chained through these links
151   Klass*      _next_link;
152 
153   // The VM's representation of the ClassLoader used to load this class.
154   // Provide access the corresponding instance java.lang.ClassLoader.
155   ClassLoaderData* _class_loader_data;
156 
157   jint        _modifier_flags;  // Processed access flags, for use by Class.getModifiers.
158   AccessFlags _access_flags;    // Access flags. The class/interface distinction is stored here.
159 
160   JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
161 

162 private:
163   // This is an index into FileMapHeader::_shared_path_table[], to
164   // associate this class with the JAR file where it's loaded from during
165   // dump time. If a class is not loaded from the shared archive, this field is
166   // -1.
167   jshort _shared_class_path_index;
168 
169 #if INCLUDE_CDS
170   // Flags of the current shared class.
171   u2     _shared_class_flags;
172   enum {
173     _archived_lambda_proxy_is_available = 2,
174     _has_value_based_class_annotation = 4,
175     _verified_at_dump_time = 8
176   };
177 #endif
178 
179   CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
180 
181 protected:

351   static ByteSize super_offset()                 { return in_ByteSize(offset_of(Klass, _super)); }
352   static ByteSize super_check_offset_offset()    { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
353   static ByteSize primary_supers_offset()        { return in_ByteSize(offset_of(Klass, _primary_supers)); }
354   static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
355   static ByteSize secondary_supers_offset()      { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
356   static ByteSize java_mirror_offset()           { return in_ByteSize(offset_of(Klass, _java_mirror)); }
357   static ByteSize class_loader_data_offset()     { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
358   static ByteSize modifier_flags_offset()        { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
359   static ByteSize layout_helper_offset()         { return in_ByteSize(offset_of(Klass, _layout_helper)); }
360   static ByteSize access_flags_offset()          { return in_ByteSize(offset_of(Klass, _access_flags)); }
361 
362   // Unpacking layout_helper:
363   static const int _lh_neutral_value           = 0;  // neutral non-array non-instance value
364   static const int _lh_instance_slow_path_bit  = 0x01;
365   static const int _lh_log2_element_size_shift = BitsPerByte*0;
366   static const int _lh_log2_element_size_mask  = BitsPerLong-1;
367   static const int _lh_element_type_shift      = BitsPerByte*1;
368   static const int _lh_element_type_mask       = right_n_bits(BitsPerByte);  // shifted mask
369   static const int _lh_header_size_shift       = BitsPerByte*2;
370   static const int _lh_header_size_mask        = right_n_bits(BitsPerByte);  // shifted mask
371   static const int _lh_array_tag_bits          = 2;
372   static const int _lh_array_tag_shift         = BitsPerInt - _lh_array_tag_bits;
373   static const int _lh_array_tag_obj_value     = ~0x01;   // 0x80000000 >> 30
374 
375   static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00,  // 0xC0000000 >> 30









376 
377   static int layout_helper_size_in_bytes(jint lh) {
378     assert(lh > (jint)_lh_neutral_value, "must be instance");
379     return (int) lh & ~_lh_instance_slow_path_bit;
380   }
381   static bool layout_helper_needs_slow_path(jint lh) {
382     assert(lh > (jint)_lh_neutral_value, "must be instance");
383     return (lh & _lh_instance_slow_path_bit) != 0;
384   }
385   static bool layout_helper_is_instance(jint lh) {
386     return (jint)lh > (jint)_lh_neutral_value;
387   }
388   static bool layout_helper_is_array(jint lh) {
389     return (jint)lh < (jint)_lh_neutral_value;
390   }
391   static bool layout_helper_is_typeArray(jint lh) {
392     // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
393     return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
394   }
395   static bool layout_helper_is_objArray(jint lh) {
396     // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
397     return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);











398   }
399   static int layout_helper_header_size(jint lh) {
400     assert(lh < (jint)_lh_neutral_value, "must be array");
401     int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
402     assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
403     return hsize;
404   }
405   static BasicType layout_helper_element_type(jint lh) {
406     assert(lh < (jint)_lh_neutral_value, "must be array");
407     int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
408     assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
409     return (BasicType) btvalue;
410   }
411 
412   // Want a pattern to quickly diff against layout header in register
413   // find something less clever!
414   static int layout_helper_boolean_diffbit() {
415     jint zlh = array_layout_helper(T_BOOLEAN);
416     jint blh = array_layout_helper(T_BYTE);
417     assert(zlh != blh, "array layout helpers must differ");
418     int diffbit = 1;
419     while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
420       diffbit <<= 1;
421       assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
422     }
423     return diffbit;
424   }
425 
426   static int layout_helper_log2_element_size(jint lh) {
427     assert(lh < (jint)_lh_neutral_value, "must be array");
428     int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
429     assert(l2esz <= LogBytesPerLong,
430            "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
431     return l2esz;
432   }
433   static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
434     return (tag        << _lh_array_tag_shift)

435       |    (hsize      << _lh_header_size_shift)
436       |    ((int)etype << _lh_element_type_shift)
437       |    (log2_esize << _lh_log2_element_size_shift);
438   }
439   static jint instance_layout_helper(jint size, bool slow_path_flag) {
440     return (size << LogBytesPerWord)
441       |    (slow_path_flag ? _lh_instance_slow_path_bit : 0);
442   }
443   static int layout_helper_to_size_helper(jint lh) {
444     assert(lh > (jint)_lh_neutral_value, "must be instance");
445     // Note that the following expression discards _lh_instance_slow_path_bit.
446     return lh >> LogBytesPerWord;
447   }
448   // Out-of-line version computes everything based on the etype:
449   static jint array_layout_helper(BasicType etype);
450 
451   // What is the maximum number of primary superclasses any klass can have?
452   static juint primary_super_limit()         { return _primary_super_limit; }
453 
454   // vtables

563   // Returns the name for a class (Resource allocated) as the class
564   // would appear in a signature.
565   // For arrays, this returns the name of the element with a leading '['.
566   // For classes, this returns the name with a leading 'L' and a trailing ';'
567   //     and the package separators as '/'.
568   virtual const char* signature_name() const;
569 
570   const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
571   const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
572 
573   // Returns "interface", "abstract class" or "class".
574   const char* external_kind() const;
575 
576   // type testing operations
577 #ifdef ASSERT
578  protected:
579   virtual bool is_instance_klass_slow()     const { return false; }
580   virtual bool is_array_klass_slow()        const { return false; }
581   virtual bool is_objArray_klass_slow()     const { return false; }
582   virtual bool is_typeArray_klass_slow()    const { return false; }

583 #endif // ASSERT


584  public:
585 
586   // Fast non-virtual versions
587   #ifndef ASSERT
588   #define assert_same_query(xval, xcheck) xval
589   #else
590  private:
591   static bool assert_same_query(bool xval, bool xslow) {
592     assert(xval == xslow, "slow and fast queries agree");
593     return xval;
594   }
595  public:
596   #endif
597   inline  bool is_instance_klass()            const { return assert_same_query(
598                                                       layout_helper_is_instance(layout_helper()),
599                                                       is_instance_klass_slow()); }
600   inline  bool is_array_klass()               const { return assert_same_query(
601                                                     layout_helper_is_array(layout_helper()),
602                                                     is_array_klass_slow()); }
603   inline  bool is_objArray_klass()            const { return assert_same_query(
604                                                     layout_helper_is_objArray(layout_helper()),
605                                                     is_objArray_klass_slow()); }
606   inline  bool is_typeArray_klass()           const { return assert_same_query(
607                                                     layout_helper_is_typeArray(layout_helper()),
608                                                     is_typeArray_klass_slow()); }





609   #undef assert_same_query
610 


611   // Access flags
612   AccessFlags access_flags() const         { return _access_flags;  }
613   void set_access_flags(AccessFlags flags) { _access_flags = flags; }
614 
615   bool is_public() const                { return _access_flags.is_public(); }
616   bool is_final() const                 { return _access_flags.is_final(); }
617   bool is_interface() const             { return _access_flags.is_interface(); }
618   bool is_abstract() const              { return _access_flags.is_abstract(); }
619   bool is_super() const                 { return _access_flags.is_super(); }
620   bool is_synthetic() const             { return _access_flags.is_synthetic(); }
621   void set_is_synthetic()               { _access_flags.set_is_synthetic(); }
622   bool has_finalizer() const            { return _access_flags.has_finalizer(); }
623   bool has_final_method() const         { return _access_flags.has_final_method(); }
624   void set_has_finalizer()              { _access_flags.set_has_finalizer(); }
625   void set_has_final_method()           { _access_flags.set_has_final_method(); }
626   bool has_vanilla_constructor() const  { return _access_flags.has_vanilla_constructor(); }
627   void set_has_vanilla_constructor()    { _access_flags.set_has_vanilla_constructor(); }
628   bool has_miranda_methods () const     { return access_flags().has_miranda_methods(); }
629   void set_has_miranda_methods()        { _access_flags.set_has_miranda_methods(); }
630   bool is_shared() const                { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
631   void set_is_shared()                  { _access_flags.set_is_shared_class(); }
632   bool is_hidden() const                { return access_flags().is_hidden_class(); }
633   void set_is_hidden()                  { _access_flags.set_is_hidden_class(); }
634   bool is_value_based()                 { return _access_flags.is_value_based_class(); }
635   void set_is_value_based()             { _access_flags.set_is_value_based_class(); }
636 
637   inline bool is_non_strong_hidden() const;
638 
639   bool is_cloneable() const;
640   void set_is_cloneable();
641 











642   JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
643 
644   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
645   virtual MetaspaceObj::Type type() const { return ClassType; }
646 
647   inline bool is_loader_alive() const;
648 
649   void clean_subklass();
650 
651   static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
652   static void clean_subklass_tree() {
653     clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
654   }
655 
656   virtual void array_klasses_do(void f(Klass* k)) {}
657 
658   // Return self, except for abstract classes with exactly 1
659   // implementor.  Then return the 1 concrete implementation.
660   Klass *up_cast_abstract();
661 

 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 IDs for all subclasses of Klass
 41 enum KlassID {
 42   InstanceKlassID,
 43   InstanceRefKlassID,
 44   InstanceMirrorKlassID,
 45   InstanceClassLoaderKlassID,
 46   TypeArrayKlassID,
 47   FlatArrayKlassID,
 48   ObjArrayKlassID
 49 };
 50 
 51 const uint KLASS_ID_COUNT = 7;
 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.
 68 template <class T> class Array;
 69 template <class T> class GrowableArray;
 70 class ClassLoaderData;
 71 class fieldDescriptor;

 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, 0xA0 if value types
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 identifier used to implement devirtualized oop closure dispatching.
119   const KlassID _id;
120 
121   // vtable length
122   int _vtable_len;

143   OopHandle   _java_mirror;
144   // Superclass
145   Klass*      _super;
146   // First subclass (NULL if none); _subklass->next_sibling() is next one
147   Klass* volatile _subklass;
148   // Sibling link (or NULL); links all subklasses of a klass
149   Klass* volatile _next_sibling;
150 
151   // All klasses loaded by a class loader are chained through these links
152   Klass*      _next_link;
153 
154   // The VM's representation of the ClassLoader used to load this class.
155   // Provide access the corresponding instance java.lang.ClassLoader.
156   ClassLoaderData* _class_loader_data;
157 
158   jint        _modifier_flags;  // Processed access flags, for use by Class.getModifiers.
159   AccessFlags _access_flags;    // Access flags. The class/interface distinction is stored here.
160 
161   JFR_ONLY(DEFINE_TRACE_ID_FIELD;)
162 
163   markWord _prototype_header;  // inline type and inline array mark patterns
164 private:
165   // This is an index into FileMapHeader::_shared_path_table[], to
166   // associate this class with the JAR file where it's loaded from during
167   // dump time. If a class is not loaded from the shared archive, this field is
168   // -1.
169   jshort _shared_class_path_index;
170 
171 #if INCLUDE_CDS
172   // Flags of the current shared class.
173   u2     _shared_class_flags;
174   enum {
175     _archived_lambda_proxy_is_available = 2,
176     _has_value_based_class_annotation = 4,
177     _verified_at_dump_time = 8
178   };
179 #endif
180 
181   CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;)
182 
183 protected:

353   static ByteSize super_offset()                 { return in_ByteSize(offset_of(Klass, _super)); }
354   static ByteSize super_check_offset_offset()    { return in_ByteSize(offset_of(Klass, _super_check_offset)); }
355   static ByteSize primary_supers_offset()        { return in_ByteSize(offset_of(Klass, _primary_supers)); }
356   static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); }
357   static ByteSize secondary_supers_offset()      { return in_ByteSize(offset_of(Klass, _secondary_supers)); }
358   static ByteSize java_mirror_offset()           { return in_ByteSize(offset_of(Klass, _java_mirror)); }
359   static ByteSize class_loader_data_offset()     { return in_ByteSize(offset_of(Klass, _class_loader_data)); }
360   static ByteSize modifier_flags_offset()        { return in_ByteSize(offset_of(Klass, _modifier_flags)); }
361   static ByteSize layout_helper_offset()         { return in_ByteSize(offset_of(Klass, _layout_helper)); }
362   static ByteSize access_flags_offset()          { return in_ByteSize(offset_of(Klass, _access_flags)); }
363 
364   // Unpacking layout_helper:
365   static const int _lh_neutral_value           = 0;  // neutral non-array non-instance value
366   static const int _lh_instance_slow_path_bit  = 0x01;
367   static const int _lh_log2_element_size_shift = BitsPerByte*0;
368   static const int _lh_log2_element_size_mask  = BitsPerLong-1;
369   static const int _lh_element_type_shift      = BitsPerByte*1;
370   static const int _lh_element_type_mask       = right_n_bits(BitsPerByte);  // shifted mask
371   static const int _lh_header_size_shift       = BitsPerByte*2;
372   static const int _lh_header_size_mask        = right_n_bits(BitsPerByte);  // shifted mask
373   static const int _lh_array_tag_bits          = 3;
374   static const int _lh_array_tag_shift         = BitsPerInt - _lh_array_tag_bits;

375 
376   static const unsigned int _lh_array_tag_type_value = 0Xfffffffc;
377   static const unsigned int _lh_array_tag_vt_value   = 0Xfffffffd;
378   static const unsigned int _lh_array_tag_obj_value  = 0Xfffffffe;
379 
380   // null-free array flag bit under the array tag bits, shift one more to get array tag value
381   static const int _lh_null_free_shift = _lh_array_tag_shift - 1;
382   static const int _lh_null_free_mask  = 1;
383 
384   static const jint _lh_array_tag_vt_value_bit_inplace = (jint) (1 << _lh_array_tag_shift);
385   static const jint _lh_null_free_bit_inplace = (jint) (_lh_null_free_mask << _lh_null_free_shift);
386 
387   static int layout_helper_size_in_bytes(jint lh) {
388     assert(lh > (jint)_lh_neutral_value, "must be instance");
389     return (int) lh & ~_lh_instance_slow_path_bit;
390   }
391   static bool layout_helper_needs_slow_path(jint lh) {
392     assert(lh > (jint)_lh_neutral_value, "must be instance");
393     return (lh & _lh_instance_slow_path_bit) != 0;
394   }
395   static bool layout_helper_is_instance(jint lh) {
396     return (jint)lh > (jint)_lh_neutral_value;
397   }
398   static bool layout_helper_is_array(jint lh) {
399     return (jint)lh < (jint)_lh_neutral_value;
400   }
401   static bool layout_helper_is_typeArray(jint lh) {
402     return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift);

403   }
404   static bool layout_helper_is_objArray(jint lh) {
405     return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift);
406   }
407   static bool layout_helper_is_flatArray(jint lh) {
408     return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift);
409   }
410   static bool layout_helper_is_null_free(jint lh) {
411     assert(layout_helper_is_flatArray(lh) || layout_helper_is_objArray(lh), "must be array of inline types");
412     return ((lh >> _lh_null_free_shift) & _lh_null_free_mask);
413   }
414   static jint layout_helper_set_null_free(jint lh) {
415     lh |= (_lh_null_free_mask << _lh_null_free_shift);
416     assert(layout_helper_is_null_free(lh), "Bad encoding");
417     return lh;
418   }
419   static int layout_helper_header_size(jint lh) {
420     assert(lh < (jint)_lh_neutral_value, "must be array");
421     int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
422     assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
423     return hsize;
424   }
425   static BasicType layout_helper_element_type(jint lh) {
426     assert(lh < (jint)_lh_neutral_value, "must be array");
427     int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
428     assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_INLINE_TYPE, "sanity");
429     return (BasicType) btvalue;
430   }
431 
432   // Want a pattern to quickly diff against layout header in register
433   // find something less clever!
434   static int layout_helper_boolean_diffbit() {
435     jint zlh = array_layout_helper(T_BOOLEAN);
436     jint blh = array_layout_helper(T_BYTE);
437     assert(zlh != blh, "array layout helpers must differ");
438     int diffbit = 1;
439     while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) {
440       diffbit <<= 1;
441       assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE");
442     }
443     return diffbit;
444   }
445 
446   static int layout_helper_log2_element_size(jint lh) {
447     assert(lh < (jint)_lh_neutral_value, "must be array");
448     int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
449     assert(layout_helper_element_type(lh) == T_INLINE_TYPE || l2esz <= LogBytesPerLong,
450            "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh);
451     return l2esz;
452   }
453   static jint array_layout_helper(jint tag, bool null_free, int hsize, BasicType etype, int log2_esize) {
454     return (tag        << _lh_array_tag_shift)
455       |    ((null_free ? 1 : 0) <<  _lh_null_free_shift)
456       |    (hsize      << _lh_header_size_shift)
457       |    ((int)etype << _lh_element_type_shift)
458       |    (log2_esize << _lh_log2_element_size_shift);
459   }
460   static jint instance_layout_helper(jint size, bool slow_path_flag) {
461     return (size << LogBytesPerWord)
462       |    (slow_path_flag ? _lh_instance_slow_path_bit : 0);
463   }
464   static int layout_helper_to_size_helper(jint lh) {
465     assert(lh > (jint)_lh_neutral_value, "must be instance");
466     // Note that the following expression discards _lh_instance_slow_path_bit.
467     return lh >> LogBytesPerWord;
468   }
469   // Out-of-line version computes everything based on the etype:
470   static jint array_layout_helper(BasicType etype);
471 
472   // What is the maximum number of primary superclasses any klass can have?
473   static juint primary_super_limit()         { return _primary_super_limit; }
474 
475   // vtables

584   // Returns the name for a class (Resource allocated) as the class
585   // would appear in a signature.
586   // For arrays, this returns the name of the element with a leading '['.
587   // For classes, this returns the name with a leading 'L' and a trailing ';'
588   //     and the package separators as '/'.
589   virtual const char* signature_name() const;
590 
591   const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const;
592   const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const;
593 
594   // Returns "interface", "abstract class" or "class".
595   const char* external_kind() const;
596 
597   // type testing operations
598 #ifdef ASSERT
599  protected:
600   virtual bool is_instance_klass_slow()     const { return false; }
601   virtual bool is_array_klass_slow()        const { return false; }
602   virtual bool is_objArray_klass_slow()     const { return false; }
603   virtual bool is_typeArray_klass_slow()    const { return false; }
604   virtual bool is_flatArray_klass_slow()    const { return false; }
605 #endif // ASSERT
606   // current implementation uses this method even in non debug builds
607   virtual bool is_inline_klass_slow()       const { return false; }
608  public:
609 
610   // Fast non-virtual versions
611   #ifndef ASSERT
612   #define assert_same_query(xval, xcheck) xval
613   #else
614  private:
615   static bool assert_same_query(bool xval, bool xslow) {
616     assert(xval == xslow, "slow and fast queries agree");
617     return xval;
618   }
619  public:
620   #endif
621   inline  bool is_instance_klass()            const { return assert_same_query(
622                                                       layout_helper_is_instance(layout_helper()),
623                                                       is_instance_klass_slow()); }
624   inline  bool is_array_klass()               const { return assert_same_query(
625                                                     layout_helper_is_array(layout_helper()),
626                                                     is_array_klass_slow()); }
627   inline  bool is_objArray_klass()            const { return assert_same_query(
628                                                     layout_helper_is_objArray(layout_helper()),
629                                                     is_objArray_klass_slow()); }
630   inline  bool is_typeArray_klass()           const { return assert_same_query(
631                                                     layout_helper_is_typeArray(layout_helper()),
632                                                     is_typeArray_klass_slow()); }
633   inline  bool is_inline_klass()              const { return is_inline_klass_slow(); } //temporary hack
634   inline  bool is_flatArray_klass()           const { return assert_same_query(
635                                                     layout_helper_is_flatArray(layout_helper()),
636                                                     is_flatArray_klass_slow()); }
637 
638   #undef assert_same_query
639 
640   inline bool is_null_free_array_klass()      const { return layout_helper_is_null_free(layout_helper()); }
641 
642   // Access flags
643   AccessFlags access_flags() const         { return _access_flags;  }
644   void set_access_flags(AccessFlags flags) { _access_flags = flags; }
645 
646   bool is_public() const                { return _access_flags.is_public(); }
647   bool is_final() const                 { return _access_flags.is_final(); }
648   bool is_interface() const             { return _access_flags.is_interface(); }
649   bool is_abstract() const              { return _access_flags.is_abstract(); }
650   bool is_super() const                 { return _access_flags.is_super(); }
651   bool is_synthetic() const             { return _access_flags.is_synthetic(); }
652   void set_is_synthetic()               { _access_flags.set_is_synthetic(); }
653   bool has_finalizer() const            { return _access_flags.has_finalizer(); }
654   bool has_final_method() const         { return _access_flags.has_final_method(); }
655   void set_has_finalizer()              { _access_flags.set_has_finalizer(); }
656   void set_has_final_method()           { _access_flags.set_has_final_method(); }
657   bool has_vanilla_constructor() const  { return _access_flags.has_vanilla_constructor(); }
658   void set_has_vanilla_constructor()    { _access_flags.set_has_vanilla_constructor(); }
659   bool has_miranda_methods () const     { return access_flags().has_miranda_methods(); }
660   void set_has_miranda_methods()        { _access_flags.set_has_miranda_methods(); }
661   bool is_shared() const                { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)()
662   void set_is_shared()                  { _access_flags.set_is_shared_class(); }
663   bool is_hidden() const                { return access_flags().is_hidden_class(); }
664   void set_is_hidden()                  { _access_flags.set_is_hidden_class(); }
665   bool is_value_based()                 { return _access_flags.is_value_based_class(); }
666   void set_is_value_based()             { _access_flags.set_is_value_based_class(); }
667 
668   inline bool is_non_strong_hidden() const;
669 
670   bool is_cloneable() const;
671   void set_is_cloneable();
672 
673   // inline types and inline type array patterns
674   markWord prototype_header() const {
675     return _prototype_header;
676   }
677   static inline markWord default_prototype_header(Klass* k) {
678     return (k == NULL) ? markWord::prototype() : k->prototype_header();
679   }
680 
681   inline void set_prototype_header(markWord header);
682   static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); }
683 
684   JFR_ONLY(DEFINE_TRACE_ID_METHODS;)
685 
686   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
687   virtual MetaspaceObj::Type type() const { return ClassType; }
688 
689   inline bool is_loader_alive() const;
690 
691   void clean_subklass();
692 
693   static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
694   static void clean_subklass_tree() {
695     clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
696   }
697 
698   virtual void array_klasses_do(void f(Klass* k)) {}
699 
700   // Return self, except for abstract classes with exactly 1
701   // implementor.  Then return the 1 concrete implementation.
702   Klass *up_cast_abstract();
703 
< prev index next >