9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "gc/shared/collectedHeap.hpp"
28 #include "memory/universe.hpp"
29 #include "prims/jvmtiGetLoadedClasses.hpp"
30 #include "runtime/jniHandles.inline.hpp"
31 #include "runtime/thread.hpp"
32 #include "utilities/stack.inline.hpp"
33 #if INCLUDE_ALL_GCS
34 #include "gc/g1/g1BarrierSet.hpp"
35 #endif
36
37
38 // The closure for GetLoadedClasses
39 class LoadedClassesClosure : public KlassClosure {
40 private:
41 Stack<jclass, mtInternal> _classStack;
42 JvmtiEnv* _env;
43 Thread* _cur_thread;
44
45 // Tell the GC to keep this klass alive
46 static void ensure_klass_alive(oop o) {
47 // A klass that was previously considered dead can be looked up in the
48 // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
49 // or a reachable object making it alive again. The SATB part of G1 needs
50 // to get notified about this potential resurrection, otherwise the marking
51 // might not find the object.
52 #if INCLUDE_ALL_GCS
53 if (UseG1GC && o != NULL) {
54 G1BarrierSet::enqueue(o);
55 }
56 #endif
57 }
58
59 public:
60 LoadedClassesClosure(Thread* thread, JvmtiEnv* env) : _cur_thread(thread), _env(env) {
61 assert(_cur_thread == Thread::current(), "must be current thread");
62 }
63
64 void do_klass(Klass* k) {
65 // Collect all jclasses
66 _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, k->java_mirror())));
67 ensure_klass_alive(k->java_mirror());
68 }
69
70 int extract(jclass* result_list) {
71 // The size of the Stack will be 0 after extract, so get it here
72 int count = (int)_classStack.size();
73 int i = count;
74
75 // Pop all jclasses, fill backwards
76 while (!_classStack.is_empty()) {
77 result_list[--i] = _classStack.pop();
78 }
79
80 // Return the number of elements written
81 return count;
82 }
83
84 // Return current size of the Stack
85 int get_count() {
86 return (int)_classStack.size();
87 }
|
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "gc/shared/collectedHeap.hpp"
28 #include "memory/universe.hpp"
29 #include "oops/access.inline.hpp"
30 #include "prims/jvmtiGetLoadedClasses.hpp"
31 #include "runtime/jniHandles.inline.hpp"
32 #include "runtime/thread.hpp"
33 #include "utilities/stack.inline.hpp"
34
35
36 // The closure for GetLoadedClasses
37 class LoadedClassesClosure : public KlassClosure {
38 private:
39 Stack<jclass, mtInternal> _classStack;
40 JvmtiEnv* _env;
41 Thread* _cur_thread;
42
43 public:
44 LoadedClassesClosure(Thread* thread, JvmtiEnv* env) : _cur_thread(thread), _env(env) {
45 assert(_cur_thread == Thread::current(), "must be current thread");
46 }
47
48 void do_klass(Klass* k) {
49 // Collect all jclasses
50 // A klass that was previously considered dead can be looked up in the
51 // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
52 // or a reachable object making it alive again. We must get the mirror via RootAccess,
53 // with ON_PHANTOM_OOP_REF to ensure that (SATB) GCs mark the mirror alive.
54 oop mirror = RootAccess<ON_PHANTOM_OOP_REF>::oop_load(k->java_mirror_handle().ptr_raw());
55 _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, mirror)));
56 }
57
58 int extract(jclass* result_list) {
59 // The size of the Stack will be 0 after extract, so get it here
60 int count = (int)_classStack.size();
61 int i = count;
62
63 // Pop all jclasses, fill backwards
64 while (!_classStack.is_empty()) {
65 result_list[--i] = _classStack.pop();
66 }
67
68 // Return the number of elements written
69 return count;
70 }
71
72 // Return current size of the Stack
73 int get_count() {
74 return (int)_classStack.size();
75 }
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