1/*
2 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
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/javaClasses.inline.hpp"
27#include "classfile/symbolTable.hpp"
28#include "jfr/jni/jfrGetAllEventClasses.hpp"
29#include "jfr/jni/jfrJavaSupport.hpp"
30#include "jfr/support/jfrEventClass.hpp"
31#include "oops/instanceKlass.hpp"
32#include "memory/allocation.inline.hpp"
33#include "memory/resourceArea.hpp"
34#include "runtime/handles.inline.hpp"
35#include "runtime/mutexLocker.hpp"
36#include "runtime/safepoint.hpp"
37#include "runtime/thread.inline.hpp"
38#include "utilities/growableArray.hpp"
39#include "utilities/stack.inline.hpp"
40
41 // incremented during class unloading (safepoint) for each unloaded event class
42static jlong unloaded_event_classes = 0;
43
44jlong JfrEventClasses::unloaded_event_classes_count() {
45 return unloaded_event_classes;
46}
47
48void JfrEventClasses::increment_unloaded_event_class() {
49 // incremented during class unloading (safepoint) for each unloaded event class
50 assert(SafepointSynchronize::is_at_safepoint(), "invariant");
51 ++unloaded_event_classes;
52}
53
54static jobject empty_java_util_arraylist = NULL;
55
56static oop new_java_util_arraylist(TRAPS) {
57 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
58 JavaValue result(T_OBJECT);
59 JfrJavaArguments args(&result, "java/util/ArrayList", "<init>", "()V", CHECK_NULL);
60 JfrJavaSupport::new_object(&args, CHECK_NULL);
61 return (oop)result.get_jobject();
62}
63
64static bool initialize(TRAPS) {
65 static bool initialized = false;
66 if (!initialized) {
67 unloaded_event_classes = 0;
68 assert(NULL == empty_java_util_arraylist, "invariant");
69 const oop array_list = new_java_util_arraylist(CHECK_false);
70 empty_java_util_arraylist = JfrJavaSupport::global_jni_handle(array_list, THREAD);
71 initialized = empty_java_util_arraylist != NULL;
72 }
73 return initialized;
74}
75
76/*
77 * Abstract klasses are filtered out unconditionally.
78 * If a klass is not yet initialized, i.e yet to run its <clinit>
79 * it is also filtered out so we don't accidentally
80 * trigger initialization.
81 */
82static bool is_whitelisted(const Klass* k) {
83 assert(k != NULL, "invariant");
84 return !(k->is_abstract() || k->should_be_initialized());
85}
86
87static void fill_klasses(GrowableArray<const void*>& event_subklasses, const Klass* event_klass, Thread* thread) {
88 assert(event_subklasses.length() == 0, "invariant");
89 assert(event_klass != NULL, "invariant");
90 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(thread));
91
92 Stack<const Klass*, mtTracing> mark_stack;
93 MutexLocker ml(Compile_lock, thread);
94 mark_stack.push(event_klass->subklass());
95
96 while (!mark_stack.is_empty()) {
97 const Klass* const current = mark_stack.pop();
98 assert(current != NULL, "null element in stack!");
99
100 if (is_whitelisted(current)) {
101 event_subklasses.append(current);
102 }
103
104 // subclass (depth)
105 const Klass* next_klass = current->subklass();
106 if (next_klass != NULL) {
107 mark_stack.push(next_klass);
108 }
109
110 // siblings (breadth)
111 next_klass = current->next_sibling();
112 if (next_klass != NULL) {
113 mark_stack.push(next_klass);
114 }
115 }
116 assert(mark_stack.is_empty(), "invariant");
117}
118
119 static void transform_klasses_to_local_jni_handles(GrowableArray<const void*>& event_subklasses, Thread* thread) {
120 assert(event_subklasses.is_nonempty(), "invariant");
121 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(thread));
122
123 for (int i = 0; i < event_subklasses.length(); ++i) {
124 const InstanceKlass* k = static_cast<const InstanceKlass*>(event_subklasses.at(i));
125 assert(is_whitelisted(k), "invariant");
126 event_subklasses.at_put(i, JfrJavaSupport::local_jni_handle(k->java_mirror(), thread));
127 }
128}
129
130static const int initial_size_growable_array = 64;
131
132jobject JfrEventClasses::get_all_event_classes(TRAPS) {
133 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
134 initialize(THREAD);
135 assert(empty_java_util_arraylist != NULL, "should have been setup already!");
136 static const char jdk_jfr_event_name[] = "jdk/internal/event/Event";
137 Symbol* const event_klass_name = SymbolTable::probe(jdk_jfr_event_name, sizeof jdk_jfr_event_name - 1);
138
139 if (NULL == event_klass_name) {
140 // not loaded yet
141 return empty_java_util_arraylist;
142 }
143
144 const Klass* const klass = SystemDictionary::resolve_or_null(event_klass_name, THREAD);
145 assert(klass != NULL, "invariant");
146 assert(JdkJfrEvent::is(klass), "invariant");
147
148 if (klass->subklass() == NULL) {
149 return empty_java_util_arraylist;
150 }
151
152 ResourceMark rm(THREAD);
153 GrowableArray<const void*> event_subklasses(THREAD, initial_size_growable_array);
154 fill_klasses(event_subklasses, klass, THREAD);
155
156 if (event_subklasses.is_empty()) {
157 return empty_java_util_arraylist;
158 }
159
160 transform_klasses_to_local_jni_handles(event_subklasses, THREAD);
161
162 Handle h_array_list(THREAD, new_java_util_arraylist(THREAD));
163 assert(h_array_list.not_null(), "invariant");
164
165 static const char add_method_name[] = "add";
166 static const char add_method_signature[] = "(Ljava/lang/Object;)Z";
167 const Klass* const array_list_klass = JfrJavaSupport::klass(empty_java_util_arraylist);
168 assert(array_list_klass != NULL, "invariant");
169
170 const Symbol* const add_method_sym = SymbolTable::new_symbol(add_method_name);
171 assert(add_method_sym != NULL, "invariant");
172
173 const Symbol* const add_method_sig_sym = SymbolTable::new_symbol(add_method_signature);
174 assert(add_method_signature != NULL, "invariant");
175
176 JavaValue result(T_BOOLEAN);
177 for (int i = 0; i < event_subklasses.length(); ++i) {
178 const jclass clazz = (const jclass)event_subklasses.at(i);
179 assert(JdkJfrEvent::is_subklass(clazz), "invariant");
180 JfrJavaArguments args(&result, array_list_klass, add_method_sym, add_method_sig_sym);
181 args.set_receiver(h_array_list());
182 args.push_jobject(clazz);
183 JfrJavaSupport::call_virtual(&args, THREAD);
184 if (HAS_PENDING_EXCEPTION || JNI_FALSE == result.get_jboolean()) {
185 return empty_java_util_arraylist;
186 }
187 }
188 return JfrJavaSupport::local_jni_handle(h_array_list(), THREAD);
189}
190