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src/hotspot/share/prims/jvmtiTagMapTable.cpp

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 46     _wh = src._wh;
 47   }
 48   // obj is always null after a copy.
 49   _obj = nullptr;
 50 }
 51 
 52 void JvmtiTagMapKey::release_weak_handle() {
 53   _wh.release(JvmtiExport::weak_tag_storage());
 54 }
 55 
 56 oop JvmtiTagMapKey::object() const {
 57   assert(_obj == nullptr, "Must have a handle and not object");
 58   return _wh.resolve();
 59 }
 60 
 61 oop JvmtiTagMapKey::object_no_keepalive() const {
 62   assert(_obj == nullptr, "Must have a handle and not object");
 63   return _wh.peek();
 64 }
 65 

















 66 static const int INITIAL_TABLE_SIZE = 1007;
 67 static const int MAX_TABLE_SIZE     = 0x3fffffff;
 68 
 69 JvmtiTagMapTable::JvmtiTagMapTable() : _table(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE) {}
 70 
 71 void JvmtiTagMapTable::clear() {
 72   struct RemoveAll {
 73     bool do_entry(JvmtiTagMapKey& entry, const jlong& tag) {
 74       entry.release_weak_handle();
 75       return true;
 76     }
 77   } remove_all;
 78   // The unlink method of ResourceHashTable gets a pointer to a type whose 'do_entry(K,V)' method is callled
 79   // while iterating over all the elements of the table. If the do_entry() method returns true the element
 80   // will be removed.
 81   // In this case, we always return true from do_entry to clear all the elements.
 82   _table.unlink(&remove_all);
 83 
 84   assert(_table.number_of_entries() == 0, "should have removed all entries");
 85 }
 86 
 87 JvmtiTagMapTable::~JvmtiTagMapTable() {
 88   clear();
 89 }
 90 
 91 jlong JvmtiTagMapTable::find(oop obj) {
 92   if (is_empty()) {
 93     return 0;
 94   }
 95 
 96   if (obj->fast_no_hash_check()) {
 97     // Objects in the table all have a hashcode.
 98     return 0;
 99   }
100 
101   JvmtiTagMapKey jtme(obj);
102   jlong* found = _table.get(jtme);
103   return found == nullptr ? 0 : *found;
104 }
105 
106 void JvmtiTagMapTable::add(oop obj, jlong tag) {
107   JvmtiTagMapKey new_entry(obj);
108   bool is_added;
109   if (obj->fast_no_hash_check()) {
110     // Can't be in the table so add it fast.
111     is_added = _table.put_when_absent(new_entry, tag);
112   } else {
113     jlong* value = _table.put_if_absent(new_entry, tag, &is_added);
114     *value = tag; // assign the new tag
115   }
116   if (is_added) {
117     if (_table.maybe_grow(5, true /* use_large_table_sizes */)) {
118       int max_bucket_size = DEBUG_ONLY(_table.verify()) NOT_DEBUG(0);
119       log_info(jvmti, table) ("JvmtiTagMap table resized to %d for %d entries max bucket %d",
120                               _table.table_size(), _table.number_of_entries(), max_bucket_size);
121     }
122   }
123 }
124 
125 void JvmtiTagMapTable::remove(oop obj) {
126   JvmtiTagMapKey jtme(obj);
127   auto clean = [] (JvmtiTagMapKey& entry, jlong tag) {
128     entry.release_weak_handle();
129   };

 46     _wh = src._wh;
 47   }
 48   // obj is always null after a copy.
 49   _obj = nullptr;
 50 }
 51 
 52 void JvmtiTagMapKey::release_weak_handle() {
 53   _wh.release(JvmtiExport::weak_tag_storage());
 54 }
 55 
 56 oop JvmtiTagMapKey::object() const {
 57   assert(_obj == nullptr, "Must have a handle and not object");
 58   return _wh.resolve();
 59 }
 60 
 61 oop JvmtiTagMapKey::object_no_keepalive() const {
 62   assert(_obj == nullptr, "Must have a handle and not object");
 63   return _wh.peek();
 64 }
 65 
 66 unsigned JvmtiTagMapKey::get_hash(const JvmtiTagMapKey& entry) {
 67   oop obj = entry._obj;
 68   assert(obj != nullptr, "must lookup obj to hash");
 69   if (obj->is_inline_type()) {
 70     // For inline types, use the klass as a hash code and let the equals match the obj.
 71     // It might have a long bucket but TBD to improve this if a customer situation arises.
 72     return (unsigned)((int64_t)obj->klass() >> 3);
 73   } else {
 74     return (unsigned)obj->identity_hash();
 75   }
 76 }
 77 
 78 // Inline types don't use hash for this table.
 79 static inline bool fast_no_hash_check(oop obj) {
 80   return (obj->fast_no_hash_check() && !obj->is_inline_type());
 81 }
 82 
 83 static const int INITIAL_TABLE_SIZE = 1007;
 84 static const int MAX_TABLE_SIZE     = 0x3fffffff;
 85 
 86 JvmtiTagMapTable::JvmtiTagMapTable() : _table(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE) {}
 87 
 88 void JvmtiTagMapTable::clear() {
 89   struct RemoveAll {
 90     bool do_entry(JvmtiTagMapKey& entry, const jlong& tag) {
 91       entry.release_weak_handle();
 92       return true;
 93     }
 94   } remove_all;
 95   // The unlink method of ResourceHashTable gets a pointer to a type whose 'do_entry(K,V)' method is callled
 96   // while iterating over all the elements of the table. If the do_entry() method returns true the element
 97   // will be removed.
 98   // In this case, we always return true from do_entry to clear all the elements.
 99   _table.unlink(&remove_all);
100 
101   assert(_table.number_of_entries() == 0, "should have removed all entries");
102 }
103 
104 JvmtiTagMapTable::~JvmtiTagMapTable() {
105   clear();
106 }
107 
108 jlong JvmtiTagMapTable::find(oop obj) {
109   if (is_empty()) {
110     return 0;
111   }
112 
113   if (fast_no_hash_check(obj)) {
114     // Objects in the table all have a hashcode, unless inlined types.
115     return 0;
116   }
117 
118   JvmtiTagMapKey jtme(obj);
119   jlong* found = _table.get(jtme);
120   return found == nullptr ? 0 : *found;
121 }
122 
123 void JvmtiTagMapTable::add(oop obj, jlong tag) {
124   JvmtiTagMapKey new_entry(obj);
125   bool is_added;
126   if (fast_no_hash_check(obj)) {
127     // Can't be in the table so add it fast.
128     is_added = _table.put_when_absent(new_entry, tag);
129   } else {
130     jlong* value = _table.put_if_absent(new_entry, tag, &is_added);
131     *value = tag; // assign the new tag
132   }
133   if (is_added) {
134     if (_table.maybe_grow(5, true /* use_large_table_sizes */)) {
135       int max_bucket_size = DEBUG_ONLY(_table.verify()) NOT_DEBUG(0);
136       log_info(jvmti, table) ("JvmtiTagMap table resized to %d for %d entries max bucket %d",
137                               _table.table_size(), _table.number_of_entries(), max_bucket_size);
138     }
139   }
140 }
141 
142 void JvmtiTagMapTable::remove(oop obj) {
143   JvmtiTagMapKey jtme(obj);
144   auto clean = [] (JvmtiTagMapKey& entry, jlong tag) {
145     entry.release_weak_handle();
146   };
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