view src/share/vm/oops/instanceKlass.hpp @ 2488:e1162778c1c8

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer. Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author johnc
date Thu, 07 Apr 2011 09:53:20 -0700
parents c7f3d0b4570f
children 92add02409c9
line wrap: on
line source
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit if you need additional information or have any
 * questions.


#include "oops/constMethodOop.hpp"
#include "oops/constantPoolOop.hpp"
#include "oops/instanceOop.hpp"
#include "oops/klassOop.hpp"
#include "oops/klassVtable.hpp"
#include "oops/objArrayOop.hpp"
#include "runtime/handles.hpp"
#include "runtime/os.hpp"
#include "utilities/accessFlags.hpp"
#include "utilities/bitMap.inline.hpp"

// An instanceKlass is the VM level representation of a Java class.
// It contains all information needed for at class at execution runtime.

//  instanceKlass layout:
//    [header                     ] klassOop
//    [klass pointer              ] klassOop
//    [C++ vtbl pointer           ] Klass
//    [subtype cache              ] Klass
//    [instance size              ] Klass
//    [java mirror                ] Klass
//    [super                      ] Klass
//    [access_flags               ] Klass
//    [name                       ] Klass
//    [first subklass             ] Klass
//    [next sibling               ] Klass
//    [array klasses              ]
//    [methods                    ]
//    [local interfaces           ]
//    [transitive interfaces      ]
//    [number of implementors     ]
//    [implementors               ] klassOop[2]
//    [fields                     ]
//    [constants                  ]
//    [class loader               ]
//    [protection domain          ]
//    [signers                    ]
//    [source file name           ]
//    [inner classes              ]
//    [static field size          ]
//    [nonstatic field size       ]
//    [static oop fields size     ]
//    [nonstatic oop maps size    ]
//    [has finalize method        ]
//    [deoptimization mark bit    ]
//    [initialization state       ]
//    [initializing thread        ]
//    [Java vtable length         ]
//    [oop map cache (stack maps) ]
//    [EMBEDDED Java vtable             ] size in words = vtable_len
//    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
//    The embedded nonstatic oop-map blocks are short pairs (offset, length) indicating
//    where oops are located in instances of this klass.

// forward declaration for class -- see below for definition
class SuperTypeClosure;
class JNIid;
class jniIdMapBase;
class BreakpointInfo;
class fieldDescriptor;
class DepChange;
class nmethodBucket;
class PreviousVersionNode;
class JvmtiCachedClassFieldMap;

// This is used in iterators below.
class FieldClosure: public StackObj {
  virtual void do_field(fieldDescriptor* fd) = 0;

#ifndef PRODUCT
// Print fields.
// If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
class FieldPrinter: public FieldClosure {
   oop _obj;
   outputStream* _st;
   FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
   void do_field(fieldDescriptor* fd);
#endif  // !PRODUCT

// ValueObjs embedded in klass. Describes where oops are located in instances of
// this klass.
class OopMapBlock VALUE_OBJ_CLASS_SPEC {
  // Byte offset of the first oop mapped by this block.
  int offset() const          { return _offset; }
  void set_offset(int offset) { _offset = offset; }

  // Number of oops in this block.
  uint count() const         { return _count; }
  void set_count(uint count) { _count = count; }

  // sizeof(OopMapBlock) in HeapWords.
  static const int size_in_words() {
    return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>

  int  _offset;
  uint _count;

class instanceKlass: public Klass {
  friend class VMStructs;
  // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
  // of the class loading & initialization procedure, and the use of the states.
  enum ClassState {
    unparsable_by_gc = 0,               // object is not yet parsable by gc. Value of _init_state at object allocation.
    allocated,                          // allocated (but not yet linked)
    loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
    linked,                             // successfully linked/verified (but not initialized yet)
    being_initialized,                  // currently running class initializer
    fully_initialized,                  // initialized (successfull final state)
    initialization_error                // error happened during initialization

  oop* oop_block_beg() const { return adr_array_klasses(); }
  oop* oop_block_end() const { return adr_methods_default_annotations() + 1; }

  enum {
    implementors_limit = 2              // how many implems can we track?

  // The oop block.  See comment in klass.hpp before making changes.

  // Array classes holding elements of this class.
  klassOop        _array_klasses;
  // Method array.
  objArrayOop     _methods;
  // Int array containing the original order of method in the class file (for
  // JVMTI).
  typeArrayOop    _method_ordering;
  // Interface (klassOops) this class declares locally to implement.
  objArrayOop     _local_interfaces;
  // Interface (klassOops) this class implements transitively.
  objArrayOop     _transitive_interfaces;
  // Instance and static variable information, 5-tuples of shorts [access, name
  // index, sig index, initval index, offset].
  typeArrayOop    _fields;
  // Constant pool for this class.
  constantPoolOop _constants;
  // Class loader used to load this class, NULL if VM loader used.
  oop             _class_loader;
  // Protection domain.
  oop             _protection_domain;
  // Host class, which grants its access privileges to this class also.
  // This is only non-null for an anonymous class (AnonymousClasses enabled).
  // The host class is either named, or a previously loaded anonymous class.
  klassOop        _host_klass;
  // Class signers.
  objArrayOop     _signers;
  // inner_classes attribute.
  typeArrayOop    _inner_classes;
  // Implementors of this interface (not valid if it overflows)
  klassOop        _implementors[implementors_limit];
  // invokedynamic bootstrap method (a java.lang.invoke.MethodHandle)
  oop             _bootstrap_method;  // AllowTransitionalJSR292 ONLY
  // Annotations for this class, or null if none.
  typeArrayOop    _class_annotations;
  // Annotation objects (byte arrays) for fields, or null if no annotations.
  // Indices correspond to entries (not indices) in fields array.
  objArrayOop     _fields_annotations;
  // Annotation objects (byte arrays) for methods, or null if no annotations.
  // Index is the idnum, which is initially the same as the methods array index.
  objArrayOop     _methods_annotations;
  // Annotation objects (byte arrays) for methods' parameters, or null if no
  // such annotations.
  // Index is the idnum, which is initially the same as the methods array index.
  objArrayOop     _methods_parameter_annotations;
  // Annotation objects (byte arrays) for methods' default values, or null if no
  // such annotations.
  // Index is the idnum, which is initially the same as the methods array index.
  objArrayOop     _methods_default_annotations;

  // End of the oop block.

  // Name of source file containing this klass, NULL if not specified.
  Symbol*         _source_file_name;
  // the source debug extension for this klass, NULL if not specified.
  Symbol*         _source_debug_extension;
  // Generic signature, or null if none.
  Symbol*         _generic_signature;
  // Array name derived from this class which needs unreferencing
  // if this class is unloaded.
  Symbol*         _array_name;

  // Number of heapOopSize words used by non-static fields in this klass
  // (including inherited fields but after header_size()).
  int             _nonstatic_field_size;
  int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
  int             _static_oop_field_count;// number of static oop fields in this klass
  int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
  bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
  bool            _rewritten;            // methods rewritten.
  bool            _has_nonstatic_fields; // for sizing with UseCompressedOops
  bool            _should_verify_class;  // allow caching of preverification
  u2              _minor_version;        // minor version number of class file
  u2              _major_version;        // major version number of class file
  ClassState      _init_state;           // state of class
  Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
  int             _vtable_len;           // length of Java vtable (in words)
  int             _itable_len;           // length of Java itable (in words)
  ReferenceType   _reference_type;       // reference type
  OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
  JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
  jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
  int*            _methods_cached_itable_indices;  // itable_index cache for JNI invoke corresponding to methods idnum, or NULL
  nmethodBucket*  _dependencies;         // list of dependent nmethods
  nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
  BreakpointInfo* _breakpoints;          // bpt lists, managed by methodOop
  int             _nof_implementors;     // No of implementors of this interface (zero if not an interface)
  // Array of interesting part(s) of the previous version(s) of this
  // instanceKlass. See PreviousVersionWalker below.
  GrowableArray<PreviousVersionNode *>* _previous_versions;
  u2              _enclosing_method_class_index;  // Constant pool index for class of enclosing method, or 0 if none
  u2              _enclosing_method_method_index; // Constant pool index for name and type of enclosing method, or 0 if none
  // JVMTI fields can be moved to their own structure - see 6315920
  unsigned char * _cached_class_file_bytes;       // JVMTI: cached class file, before retransformable agent modified it in CFLH
  jint            _cached_class_file_len;         // JVMTI: length of above
  JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
  volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change

  // embedded Java vtable follows here
  // embedded Java itables follows here
  // embedded static fields follows here
  // embedded nonstatic oop-map blocks follows here

  friend class instanceKlassKlass;
  friend class SystemDictionary;

  bool has_nonstatic_fields() const        { return _has_nonstatic_fields; }
  void set_has_nonstatic_fields(bool b)    { _has_nonstatic_fields = b; }

  // field sizes
  int nonstatic_field_size() const         { return _nonstatic_field_size; }
  void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }

  int static_field_size() const            { return _static_field_size; }
  void set_static_field_size(int size)     { _static_field_size = size; }

  int static_oop_field_count() const        { return _static_oop_field_count; }
  void set_static_oop_field_count(int size) { _static_oop_field_count = size; }

  // Java vtable
  int  vtable_length() const               { return _vtable_len; }
  void set_vtable_length(int len)          { _vtable_len = len; }

  // Java itable
  int  itable_length() const               { return _itable_len; }
  void set_itable_length(int len)          { _itable_len = len; }

  // array klasses
  klassOop array_klasses() const           { return _array_klasses; }
  void set_array_klasses(klassOop k)       { oop_store_without_check((oop*) &_array_klasses, (oop) k); }

  // methods
  objArrayOop methods() const              { return _methods; }
  void set_methods(objArrayOop a)          { oop_store_without_check((oop*) &_methods, (oop) a); }
  methodOop method_with_idnum(int idnum);

  // method ordering
  typeArrayOop method_ordering() const     { return _method_ordering; }
  void set_method_ordering(typeArrayOop m) { oop_store_without_check((oop*) &_method_ordering, (oop) m); }

  // interfaces
  objArrayOop local_interfaces() const          { return _local_interfaces; }
  void set_local_interfaces(objArrayOop a)      { oop_store_without_check((oop*) &_local_interfaces, (oop) a); }
  objArrayOop transitive_interfaces() const     { return _transitive_interfaces; }
  void set_transitive_interfaces(objArrayOop a) { oop_store_without_check((oop*) &_transitive_interfaces, (oop) a); }

  // fields
  // Field info extracted from the class file and stored
  // as an array of 7 shorts
  enum FieldOffset {
    access_flags_offset    = 0,
    name_index_offset      = 1,
    signature_index_offset = 2,
    initval_index_offset   = 3,
    low_offset             = 4,
    high_offset            = 5,
    generic_signature_offset = 6,
    next_offset            = 7

  typeArrayOop fields() const              { return _fields; }
  int offset_from_fields( int index ) const {
    return build_int_from_shorts( fields()->ushort_at(index + low_offset),
                                  fields()->ushort_at(index + high_offset) );

  void set_fields(typeArrayOop f)          { oop_store_without_check((oop*) &_fields, (oop) f); }

  // inner classes
  typeArrayOop inner_classes() const       { return _inner_classes; }
  void set_inner_classes(typeArrayOop f)   { oop_store_without_check((oop*) &_inner_classes, (oop) f); }

  enum InnerClassAttributeOffset {
    // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
    inner_class_inner_class_info_offset = 0,
    inner_class_outer_class_info_offset = 1,
    inner_class_inner_name_offset = 2,
    inner_class_access_flags_offset = 3,
    inner_class_next_offset = 4

  // method override check
  bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);

  // package
  bool is_same_class_package(klassOop class2);
  bool is_same_class_package(oop classloader2, Symbol* classname2);
  static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);

  // find an enclosing class (defined where original code was, in jvm.cpp!)
  klassOop compute_enclosing_class(bool* inner_is_member, TRAPS) {
    instanceKlassHandle self(THREAD, this->as_klassOop());
    return compute_enclosing_class_impl(self, inner_is_member, THREAD);
  static klassOop compute_enclosing_class_impl(instanceKlassHandle self,
                                               bool* inner_is_member, TRAPS);

  // tell if two classes have the same enclosing class (at package level)
  bool is_same_package_member(klassOop class2, TRAPS) {
    instanceKlassHandle self(THREAD, this->as_klassOop());
    return is_same_package_member_impl(self, class2, THREAD);
  static bool is_same_package_member_impl(instanceKlassHandle self,
                                          klassOop class2, TRAPS);

  // initialization state
  bool is_loaded() const                   { return _init_state >= loaded; }
  bool is_linked() const                   { return _init_state >= linked; }
  bool is_initialized() const              { return _init_state == fully_initialized; }
  bool is_not_initialized() const          { return _init_state <  being_initialized; }
  bool is_being_initialized() const        { return _init_state == being_initialized; }
  bool is_in_error_state() const           { return _init_state == initialization_error; }
  bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
  int  get_init_state()                    { return _init_state; } // Useful for debugging
  bool is_rewritten() const                { return _rewritten; }

  // defineClass specified verification
  bool should_verify_class() const         { return _should_verify_class; }
  void set_should_verify_class(bool value) { _should_verify_class = value; }

  // marking
  bool is_marked_dependent() const         { return _is_marked_dependent; }
  void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }

  // initialization (virtuals from Klass)
  bool should_be_initialized() const;  // means that initialize should be called
  void initialize(TRAPS);
  void link_class(TRAPS);
  bool link_class_or_fail(TRAPS); // returns false on failure
  void unlink_class();
  void rewrite_class(TRAPS);
  methodOop class_initializer();

  // set the class to initialized if no static initializer is present
  void eager_initialize(Thread *thread);

  // reference type
  ReferenceType reference_type() const     { return _reference_type; }
  void set_reference_type(ReferenceType t) { _reference_type = t; }

  static int reference_type_offset_in_bytes() { return offset_of(instanceKlass, _reference_type); }

  // find local field, returns true if found
  bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
  // find field in direct superinterfaces, returns the interface in which the field is defined
  klassOop find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
  // find field according to JVM spec, returns the klass in which the field is defined
  klassOop find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
  // find instance or static fields according to JVM spec, returns the klass in which the field is defined
  klassOop find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;

  // find a non-static or static field given its offset within the class.
  bool contains_field_offset(int offset) {
    return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());

  bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
  bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;

  // find a local method (returns NULL if not found)
  methodOop find_method(Symbol* name, Symbol* signature) const;
  static methodOop find_method(objArrayOop methods, Symbol* name, Symbol* signature);

  // lookup operation (returns NULL if not found)
  methodOop uncached_lookup_method(Symbol* name, Symbol* signature) const;

  // lookup a method in all the interfaces that this class implements
  // (returns NULL if not found)
  methodOop lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;

  // constant pool
  constantPoolOop constants() const        { return _constants; }
  void set_constants(constantPoolOop c)    { oop_store_without_check((oop*) &_constants, (oop) c); }

  // class loader
  oop class_loader() const                 { return _class_loader; }
  void set_class_loader(oop l)             { oop_store((oop*) &_class_loader, l); }

  // protection domain
  oop protection_domain()                  { return _protection_domain; }
  void set_protection_domain(oop pd)       { oop_store((oop*) &_protection_domain, pd); }

  // host class
  oop host_klass() const                   { return _host_klass; }
  void set_host_klass(oop host)            { oop_store((oop*) &_host_klass, host); }
  bool is_anonymous() const                { return _host_klass != NULL; }

  // signers
  objArrayOop signers() const              { return _signers; }
  void set_signers(objArrayOop s)          { oop_store((oop*) &_signers, oop(s)); }

  // source file name
  Symbol* source_file_name() const         { return _source_file_name; }
  void set_source_file_name(Symbol* n);

  // minor and major version numbers of class file
  u2 minor_version() const                 { return _minor_version; }
  void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
  u2 major_version() const                 { return _major_version; }
  void set_major_version(u2 major_version) { _major_version = major_version; }

  // source debug extension
  Symbol* source_debug_extension() const   { return _source_debug_extension; }
  void set_source_debug_extension(Symbol* n);

  // symbol unloading support (refcount already added)
  Symbol* array_name()                     { return _array_name; }
  void set_array_name(Symbol* name)        { assert(_array_name == NULL, "name already created"); _array_name = name; }

  // nonstatic oop-map blocks
  static int nonstatic_oop_map_size(unsigned int oop_map_count) {
    return oop_map_count * OopMapBlock::size_in_words();
  unsigned int nonstatic_oop_map_count() const {
    return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
  int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
  void set_nonstatic_oop_map_size(int words) {
    _nonstatic_oop_map_size = words;

  // RedefineClasses() support for previous versions:
  void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
         int emcp_method_count);
  // If the _previous_versions array is non-NULL, then this klass
  // has been redefined at least once even if we aren't currently
  // tracking a previous version.
  bool has_been_redefined() const { return _previous_versions != NULL; }
  bool has_previous_version() const;
  void init_previous_versions() {
    _previous_versions = NULL;
  GrowableArray<PreviousVersionNode *>* previous_versions() const {
    return _previous_versions;

  // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
  void set_cached_class_file(unsigned char *class_file_bytes,
                             jint class_file_len)     { _cached_class_file_len = class_file_len;
                                                        _cached_class_file_bytes = class_file_bytes; }
  jint get_cached_class_file_len()                    { return _cached_class_file_len; }
  unsigned char * get_cached_class_file_bytes()       { return _cached_class_file_bytes; }

  // JVMTI: Support for caching of field indices, types, and offsets
  void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
    _jvmti_cached_class_field_map = descriptor;
  JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
    return _jvmti_cached_class_field_map;

  // for adding methods, constMethodOopDesc::UNSET_IDNUM means no more ids available
  inline u2 next_method_idnum();
  void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }

  // generics support
  Symbol* generic_signature() const                   { return _generic_signature; }
  void set_generic_signature(Symbol* sig)             { _generic_signature = sig; }

  u2 enclosing_method_class_index() const             { return _enclosing_method_class_index; }
  u2 enclosing_method_method_index() const            { return _enclosing_method_method_index; }
  void set_enclosing_method_indices(u2 class_index,
                                    u2 method_index)  { _enclosing_method_class_index  = class_index;
                                                        _enclosing_method_method_index = method_index; }

  // JSR 292 support
  oop bootstrap_method() const                        { return _bootstrap_method; }  // AllowTransitionalJSR292 ONLY
  void set_bootstrap_method(oop mh)                   { oop_store(&_bootstrap_method, mh); }

  // jmethodID support
  static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
                     methodHandle method_h);
  static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
                     size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
                     jmethodID* to_dealloc_id_p,
                     jmethodID** to_dealloc_jmeths_p);
  static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
                size_t *length_p, jmethodID* id_p);
  jmethodID jmethod_id_or_null(methodOop method);

  // cached itable index support
  void set_cached_itable_index(size_t idnum, int index);
  int cached_itable_index(size_t idnum);

  // annotations support
  typeArrayOop class_annotations() const              { return _class_annotations; }
  objArrayOop fields_annotations() const              { return _fields_annotations; }
  objArrayOop methods_annotations() const             { return _methods_annotations; }
  objArrayOop methods_parameter_annotations() const   { return _methods_parameter_annotations; }
  objArrayOop methods_default_annotations() const     { return _methods_default_annotations; }
  void set_class_annotations(typeArrayOop md)            { oop_store_without_check((oop*)&_class_annotations, (oop)md); }
  void set_fields_annotations(objArrayOop md)            { set_annotations(md, &_fields_annotations); }
  void set_methods_annotations(objArrayOop md)           { set_annotations(md, &_methods_annotations); }
  void set_methods_parameter_annotations(objArrayOop md) { set_annotations(md, &_methods_parameter_annotations); }
  void set_methods_default_annotations(objArrayOop md)   { set_annotations(md, &_methods_default_annotations); }
  typeArrayOop get_method_annotations_of(int idnum)
                                                { return get_method_annotations_from(idnum, _methods_annotations); }
  typeArrayOop get_method_parameter_annotations_of(int idnum)
                                                { return get_method_annotations_from(idnum, _methods_parameter_annotations); }
  typeArrayOop get_method_default_annotations_of(int idnum)
                                                { return get_method_annotations_from(idnum, _methods_default_annotations); }
  void set_method_annotations_of(int idnum, typeArrayOop anno)
                                                { set_methods_annotations_of(idnum, anno, &_methods_annotations); }
  void set_method_parameter_annotations_of(int idnum, typeArrayOop anno)
                                                { set_methods_annotations_of(idnum, anno, &_methods_annotations); }
  void set_method_default_annotations_of(int idnum, typeArrayOop anno)
                                                { set_methods_annotations_of(idnum, anno, &_methods_annotations); }

  // allocation
  instanceOop allocate_instance(TRAPS);
  instanceOop allocate_permanent_instance(TRAPS);

  // additional member function to return a handle
  instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }

  objArrayOop allocate_objArray(int n, int length, TRAPS);
  // Helper function
  static instanceOop register_finalizer(instanceOop i, TRAPS);

  // Check whether reflection/jni/jvm code is allowed to instantiate this class;
  // if not, throw either an Error or an Exception.
  virtual void check_valid_for_instantiation(bool throwError, TRAPS);

  // initialization
  void call_class_initializer(TRAPS);
  void set_initialization_state_and_notify(ClassState state, TRAPS);

  // OopMapCache support
  OopMapCache* oop_map_cache()               { return _oop_map_cache; }
  void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
  void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);

  // JNI identifier support (for static fields - for jni performance)
  JNIid* jni_ids()                               { return _jni_ids; }
  void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
  JNIid* jni_id_for(int offset);

  // maintenance of deoptimization dependencies
  int mark_dependent_nmethods(DepChange& changes);
  void add_dependent_nmethod(nmethod* nm);
  void remove_dependent_nmethod(nmethod* nm);

  // On-stack replacement support
  nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
  void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
  void add_osr_nmethod(nmethod* n);
  void remove_osr_nmethod(nmethod* n);
  nmethod* lookup_osr_nmethod(const methodOop m, int bci, int level, bool match_level) const;

  // Breakpoint support (see methods on methodOop for details)
  BreakpointInfo* breakpoints() const       { return _breakpoints; };
  void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };

  // support for stub routines
  static int init_state_offset_in_bytes()    { return offset_of(instanceKlass, _init_state); }
  static int init_thread_offset_in_bytes()   { return offset_of(instanceKlass, _init_thread); }

  // subclass/subinterface checks
  bool implements_interface(klassOop k) const;

  // Access to implementors of an interface. We only store the count
  // of implementors, and in case, there are only a few
  // implementors, we store them in a short list.
  // This accessor returns NULL if we walk off the end of the list.
  klassOop implementor(int i) const {
    return (i < implementors_limit)? _implementors[i]: (klassOop) NULL;
  int  nof_implementors() const       { return _nof_implementors; }
  void add_implementor(klassOop k);  // k is a new class that implements this interface
  void init_implementor();           // initialize

  // link this class into the implementors list of every interface it implements
  void process_interfaces(Thread *thread);

  // virtual operations from Klass
  bool is_leaf_class() const               { return _subklass == NULL; }
  objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS);
  bool compute_is_subtype_of(klassOop k);
  bool can_be_primary_super_slow() const;
  klassOop java_super() const              { return super(); }
  int oop_size(oop obj)  const             { return size_helper(); }
  int klass_oop_size() const               { return object_size(); }
  bool oop_is_instance_slow() const        { return true; }

  // Iterators
  void do_local_static_fields(FieldClosure* cl);
  void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
  void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);

  void methods_do(void f(methodOop method));
  void array_klasses_do(void f(klassOop k));
  void with_array_klasses_do(void f(klassOop k));
  bool super_types_do(SuperTypeClosure* blk);

  // Casting from klassOop
  static instanceKlass* cast(klassOop k) {
    assert(k->is_klass(), "must be");
    Klass* kp = k->klass_part();
    assert(kp->null_vtbl() || kp->oop_is_instance_slow(), "cast to instanceKlass");
    return (instanceKlass*) kp;

  // Sizing (in words)
  static int header_size()            { return align_object_offset(oopDesc::header_size() + sizeof(instanceKlass)/HeapWordSize); }
  int object_size() const             { return object_size(align_object_offset(vtable_length()) + align_object_offset(itable_length()) + nonstatic_oop_map_size()); }
  static int vtable_start_offset()    { return header_size(); }
  static int vtable_length_offset()   { return oopDesc::header_size() + offset_of(instanceKlass, _vtable_len) / HeapWordSize; }
  static int object_size(int extra)   { return align_object_size(header_size() + extra); }

  intptr_t* start_of_vtable() const        { return ((intptr_t*)as_klassOop()) + vtable_start_offset(); }
  intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
  int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)as_klassOop(); }

  intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }

  address static_field_addr(int offset);

  OopMapBlock* start_of_nonstatic_oop_maps() const {
    return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));

  // Allocation profiling support
  juint alloc_size() const            { return _alloc_count * size_helper(); }
  void set_alloc_size(juint n)        {}

  // Use this to return the size of an instance in heap words:
  int size_helper() const {
    return layout_helper_to_size_helper(layout_helper());

  // This bit is initialized in classFileParser.cpp.
  // It is false under any of the following conditions:
  //  - the class is abstract (including any interface)
  //  - the class has a finalizer (if !RegisterFinalizersAtInit)
  //  - the class size is larger than FastAllocateSizeLimit
  //  - the class is java/lang/Class, which cannot be allocated directly
  bool can_be_fastpath_allocated() const {
    return !layout_helper_needs_slow_path(layout_helper());

  // Java vtable/itable
  klassVtable* vtable() const;        // return new klassVtable wrapper
  inline methodOop method_at_vtable(int index);
  klassItable* itable() const;        // return new klassItable wrapper
  methodOop method_at_itable(klassOop holder, int index, TRAPS);

  // Garbage collection
  void oop_follow_contents(oop obj);
  int  oop_adjust_pointers(oop obj);
  bool object_is_parsable() const { return _init_state != unparsable_by_gc; }
       // Value of _init_state must be zero (unparsable_by_gc) when klass field is set.

  void follow_weak_klass_links(
    BoolObjectClosure* is_alive, OopClosure* keep_alive);
  void release_C_heap_structures();

  // Parallel Scavenge and Parallel Old

  // Naming
  const char* signature_name() const;

  // Iterators
  int oop_oop_iterate(oop obj, OopClosure* blk) {
    return oop_oop_iterate_v(obj, blk);

  int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {
    return oop_oop_iterate_v_m(obj, blk, mr);

#define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
  int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
  int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
                                      MemRegion mr);


#ifndef SERIALGC
#define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
  int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);

#endif // !SERIALGC

  // initialization state
#ifdef ASSERT
  void set_init_state(ClassState state);
  void set_init_state(ClassState state) { _init_state = state; }
  void set_rewritten()                  { _rewritten = true; }
  void set_init_thread(Thread *thread)  { _init_thread = thread; }

  u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
  // The RedefineClasses() API can cause new method idnums to be needed
  // which will cause the caches to grow. Safety requires different
  // cache management logic if the caches can grow instead of just
  // going from NULL to non-NULL.
  bool idnum_can_increment() const      { return has_been_redefined(); }
  jmethodID* methods_jmethod_ids_acquire() const
         { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
  void release_set_methods_jmethod_ids(jmethodID* jmeths)
         { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }

  int* methods_cached_itable_indices_acquire() const
         { return (int*)OrderAccess::load_ptr_acquire(&_methods_cached_itable_indices); }
  void release_set_methods_cached_itable_indices(int* indices)
         { OrderAccess::release_store_ptr(&_methods_cached_itable_indices, indices); }

  inline typeArrayOop get_method_annotations_from(int idnum, objArrayOop annos);
  void set_annotations(objArrayOop md, objArrayOop* md_p)  { oop_store_without_check((oop*)md_p, (oop)md); }
  void set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p);

  // Offsets for memory management
  oop* adr_array_klasses() const     { return (oop*)&this->_array_klasses;}
  oop* adr_methods() const           { return (oop*)&this->_methods;}
  oop* adr_method_ordering() const   { return (oop*)&this->_method_ordering;}
  oop* adr_local_interfaces() const  { return (oop*)&this->_local_interfaces;}
  oop* adr_transitive_interfaces() const  { return (oop*)&this->_transitive_interfaces;}
  oop* adr_fields() const            { return (oop*)&this->_fields;}
  oop* adr_constants() const         { return (oop*)&this->_constants;}
  oop* adr_class_loader() const      { return (oop*)&this->_class_loader;}
  oop* adr_protection_domain() const { return (oop*)&this->_protection_domain;}
  oop* adr_host_klass() const        { return (oop*)&this->_host_klass;}
  oop* adr_signers() const           { return (oop*)&this->_signers;}
  oop* adr_inner_classes() const     { return (oop*)&this->_inner_classes;}
  oop* adr_implementors() const      { return (oop*)&this->_implementors[0];}
  oop* adr_bootstrap_method() const  { return (oop*)&this->_bootstrap_method;}  // AllowTransitionalJSR292 ONLY
  oop* adr_methods_jmethod_ids() const             { return (oop*)&this->_methods_jmethod_ids;}
  oop* adr_methods_cached_itable_indices() const   { return (oop*)&this->_methods_cached_itable_indices;}
  oop* adr_class_annotations() const   { return (oop*)&this->_class_annotations;}
  oop* adr_fields_annotations() const  { return (oop*)&this->_fields_annotations;}
  oop* adr_methods_annotations() const { return (oop*)&this->_methods_annotations;}
  oop* adr_methods_parameter_annotations() const { return (oop*)&this->_methods_parameter_annotations;}
  oop* adr_methods_default_annotations() const { return (oop*)&this->_methods_default_annotations;}

  // Static methods that are used to implement member methods where an exposed this pointer
  // is needed due to possible GCs
  static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
  static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
  static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
  static void eager_initialize_impl                     (instanceKlassHandle this_oop);
  static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
  static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
  static klassOop array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
  static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
  /* jni_id_for_impl for jfieldID only */
  static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);

  // Returns the array class for the n'th dimension
  klassOop array_klass_impl(bool or_null, int n, TRAPS);

  // Returns the array class with this class as element type
  klassOop array_klass_impl(bool or_null, TRAPS);

  // sharing support
  virtual void remove_unshareable_info();
  virtual void shared_symbols_iterate(SymbolClosure* closure);

  // jvm support
  jint compute_modifier_flags(TRAPS) const;

  // JVMTI support
  jint jvmti_class_status() const;

  // Printing
  void oop_print_value_on(oop obj, outputStream* st);
#ifndef PRODUCT
  void oop_print_on      (oop obj, outputStream* st);

  void print_dependent_nmethods(bool verbose = false);
  bool is_dependent_nmethod(nmethod* nm);

  // Verification
  const char* internal_name() const;
  void oop_verify_on(oop obj, outputStream* st);

#ifndef PRODUCT
  static void verify_class_klass_nonstatic_oop_maps(klassOop k) PRODUCT_RETURN;

inline methodOop instanceKlass::method_at_vtable(int index)  {
#ifndef PRODUCT
  assert(index >= 0, "valid vtable index");
  if (DebugVtables) {
  vtableEntry* ve = (vtableEntry*)start_of_vtable();
  return ve[index].method();

inline typeArrayOop instanceKlass::get_method_annotations_from(int idnum, objArrayOop annos) {
  if (annos == NULL || annos->length() <= idnum) {
    return NULL;
  return typeArrayOop(annos->obj_at(idnum));

// for adding methods
// UNSET_IDNUM return means no more ids available
inline u2 instanceKlass::next_method_idnum() {
  if (_idnum_allocated_count == constMethodOopDesc::MAX_IDNUM) {
    return constMethodOopDesc::UNSET_IDNUM; // no more ids available
  } else {
    return _idnum_allocated_count++;

/* JNIid class for jfieldIDs only */
class JNIid: public CHeapObj {
  friend class VMStructs;
  klassOop           _holder;
  JNIid*             _next;
  int                _offset;
#ifdef ASSERT
  bool               _is_static_field_id;

  // Accessors
  klassOop holder() const         { return _holder; }
  int offset() const              { return _offset; }
  JNIid* next()                   { return _next; }
  // Constructor
  JNIid(klassOop holder, int offset, JNIid* next);
  // Identifier lookup
  JNIid* find(int offset);

  bool find_local_field(fieldDescriptor* fd) {
    return instanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);

  // Garbage collection support
  oop* holder_addr() { return (oop*)&_holder; }
  void oops_do(OopClosure* f);
  static void deallocate(JNIid* id);
  // Debugging
#ifdef ASSERT
  bool is_static_field_id() const { return _is_static_field_id; }
  void set_is_static_field_id()   { _is_static_field_id = true; }
  void verify(klassOop holder);

// If breakpoints are more numerous than just JVMTI breakpoints,
// consider compressing this data structure.
// It is currently a simple linked list defined in methodOop.hpp.

class BreakpointInfo;

// A collection point for interesting information about the previous
// version(s) of an instanceKlass. This class uses weak references to
// the information so that the information may be collected as needed
// by the system. If the information is shared, then a regular
// reference must be used because a weak reference would be seen as
// collectible. A GrowableArray of PreviousVersionNodes is attached
// to the instanceKlass as needed. See PreviousVersionWalker below.
class PreviousVersionNode : public CHeapObj {
  // A shared ConstantPool is never collected so we'll always have
  // a reference to it so we can update items in the cache. We'll
  // have a weak reference to a non-shared ConstantPool until all
  // of the methods (EMCP or obsolete) have been collected; the
  // non-shared ConstantPool becomes collectible at that point.
  jobject _prev_constant_pool;  // regular or weak reference
  bool    _prev_cp_is_weak;     // true if not a shared ConstantPool

  // If the previous version of the instanceKlass doesn't have any
  // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
  // EMCP methods have been collected, then _prev_EMCP_methods can
  // have a length of zero.
  GrowableArray<jweak>* _prev_EMCP_methods;

  PreviousVersionNode(jobject prev_constant_pool, bool prev_cp_is_weak,
    GrowableArray<jweak>* prev_EMCP_methods);
  jobject prev_constant_pool() const {
    return _prev_constant_pool;
  GrowableArray<jweak>* prev_EMCP_methods() const {
    return _prev_EMCP_methods;

// A Handle-ized version of PreviousVersionNode.
class PreviousVersionInfo : public ResourceObj {
  constantPoolHandle   _prev_constant_pool_handle;
  // If the previous version of the instanceKlass doesn't have any
  // EMCP methods, then _prev_EMCP_methods will be NULL. Since the
  // methods cannot be collected while we hold a handle,
  // _prev_EMCP_methods should never have a length of zero.
  GrowableArray<methodHandle>* _prev_EMCP_method_handles;

  PreviousVersionInfo(PreviousVersionNode *pv_node);
  constantPoolHandle prev_constant_pool_handle() const {
    return _prev_constant_pool_handle;
  GrowableArray<methodHandle>* prev_EMCP_method_handles() const {
    return _prev_EMCP_method_handles;

// Helper object for walking previous versions. This helper cleans up
// the Handles that it allocates when the helper object is destroyed.
// The PreviousVersionInfo object returned by next_previous_version()
// is only valid until a subsequent call to next_previous_version() or
// the helper object is destroyed.
class PreviousVersionWalker : public StackObj {
  GrowableArray<PreviousVersionNode *>* _previous_versions;
  int                                   _current_index;
  // Fields for cleaning up when we are done walking the previous versions:
  // A HandleMark for the PreviousVersionInfo handles:
  HandleMark                            _hm;

  // It would be nice to have a ResourceMark field in this helper also,
  // but the ResourceMark code says to be careful to delete handles held
  // in GrowableArrays _before_ deleting the GrowableArray. Since we
  // can't guarantee the order in which the fields are destroyed, we
  // have to let the creator of the PreviousVersionWalker object do
  // the right thing. Also, adding a ResourceMark here causes an
  // include loop.

  // A pointer to the current info object so we can handle the deletes.
  PreviousVersionInfo *                 _current_p;

  PreviousVersionWalker(instanceKlass *ik);

  // Return the interesting information for the next previous version
  // of the klass. Returns NULL if there are no more previous versions.
  PreviousVersionInfo* next_previous_version();