1 /*
  2  * Copyright (c) 2011, 2021, 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/classLoaderData.inline.hpp"
 27 #include "classfile/javaClasses.inline.hpp"
 28 #include "classfile/symbolTable.hpp"
 29 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp"
 30 #include "jfr/utilities/jfrTypes.hpp"
 31 #include "oops/arrayKlass.inline.hpp"
 32 #include "oops/klass.inline.hpp"
 33 #include "oops/instanceKlass.inline.hpp"
 34 #include "oops/method.hpp"
 35 #include "oops/oop.inline.hpp"
 36 #include "runtime/atomic.hpp"
 37 #include "runtime/vm_version.hpp"
 38 #include "runtime/jniHandles.inline.hpp"
 39 #include "runtime/thread.inline.hpp"
 40 #include "utilities/debug.hpp"
 41 
 42  // returns updated value
 43 static traceid atomic_inc(traceid volatile* const dest) {
 44   assert(VM_Version::supports_cx8(), "invariant");
 45   traceid compare_value;
 46   traceid exchange_value;
 47   do {
 48     compare_value = *dest;
 49     exchange_value = compare_value + 1;
 50   } while (Atomic::cmpxchg(dest, compare_value, exchange_value) != compare_value);
 51   return exchange_value;
 52 }
 53 
 54 static traceid next_class_id() {
 55   static volatile traceid class_id_counter = LAST_TYPE_ID + 1; // + 1 is for the void.class primitive
 56   return atomic_inc(&class_id_counter) << TRACE_ID_SHIFT;
 57 }
 58 
 59 static traceid next_thread_id() {
 60   static volatile traceid thread_id_counter = 0;
 61   return atomic_inc(&thread_id_counter);
 62 }
 63 
 64 static traceid next_module_id() {
 65   static volatile traceid module_id_counter = 0;
 66   return atomic_inc(&module_id_counter) << TRACE_ID_SHIFT;
 67 }
 68 
 69 static traceid next_package_id() {
 70   static volatile traceid package_id_counter = 0;
 71   return atomic_inc(&package_id_counter) << TRACE_ID_SHIFT;
 72 }
 73 
 74 static traceid next_class_loader_data_id() {
 75   static volatile traceid cld_id_counter = 0;
 76   return atomic_inc(&cld_id_counter) << TRACE_ID_SHIFT;
 77 }
 78 
 79 static bool found_jdk_internal_event_klass = false;
 80 static bool found_jdk_jfr_event_klass = false;
 81 
 82 static void check_klass(const Klass* klass) {
 83   assert(klass != NULL, "invariant");
 84   if (found_jdk_internal_event_klass && found_jdk_jfr_event_klass) {
 85     return;
 86   }
 87   static const Symbol* jdk_internal_event_sym = NULL;
 88   if (jdk_internal_event_sym == NULL) {
 89     // setup when loading the first TypeArrayKlass (Universe::genesis) hence single threaded invariant
 90     jdk_internal_event_sym = SymbolTable::new_permanent_symbol("jdk/internal/event/Event");
 91   }
 92   assert(jdk_internal_event_sym != NULL, "invariant");
 93 
 94   static const Symbol* jdk_jfr_event_sym = NULL;
 95   if (jdk_jfr_event_sym == NULL) {
 96     // setup when loading the first TypeArrayKlass (Universe::genesis) hence single threaded invariant
 97     jdk_jfr_event_sym = SymbolTable::new_permanent_symbol("jdk/jfr/Event");
 98   }
 99   assert(jdk_jfr_event_sym != NULL, "invariant");
100   const Symbol* const klass_name = klass->name();
101 
102   if (!found_jdk_internal_event_klass) {
103     if (jdk_internal_event_sym == klass_name && klass->class_loader() == NULL) {
104       found_jdk_internal_event_klass = true;
105       JfrTraceId::tag_as_jdk_jfr_event(klass);
106       return;
107     }
108   }
109 
110   if (!found_jdk_jfr_event_klass) {
111     if (jdk_jfr_event_sym == klass_name && klass->class_loader() == NULL) {
112       found_jdk_jfr_event_klass = true;
113       JfrTraceId::tag_as_jdk_jfr_event(klass);
114       return;
115     }
116   }
117 }
118 
119 void JfrTraceId::assign(const Klass* klass) {
120   assert(klass != NULL, "invariant");
121   klass->set_trace_id(next_class_id());
122   check_klass(klass);
123   const Klass* const super = klass->super();
124   if (super == NULL) {
125     return;
126   }
127   if (IS_EVENT_KLASS(super)) {
128     tag_as_jdk_jfr_event_sub(klass);
129   }
130 }
131 
132 void JfrTraceId::assign(const ModuleEntry* module) {
133   assert(module != NULL, "invariant");
134   module->set_trace_id(next_module_id());
135 }
136 
137 void JfrTraceId::assign(const PackageEntry* package) {
138   assert(package != NULL, "invariant");
139   package->set_trace_id(next_package_id());
140 }
141 
142 void JfrTraceId::assign(const ClassLoaderData* cld) {
143   assert(cld != NULL, "invariant");
144   if (cld->has_class_mirror_holder()) {
145     cld->set_trace_id(0);
146     return;
147   }
148   cld->set_trace_id(next_class_loader_data_id());
149 }
150 
151 traceid JfrTraceId::assign_primitive_klass_id() {
152   return next_class_id();
153 }
154 
155 traceid JfrTraceId::assign_thread_id() {
156   return next_thread_id();
157 }
158 
159 // A mirror representing a primitive class (e.g. int.class) has no reified Klass*,
160 // instead it has an associated TypeArrayKlass* (e.g. int[].class).
161 // We can use the TypeArrayKlass* as a proxy for deriving the id of the primitive class.
162 // The exception is the void.class, which has neither a Klass* nor a TypeArrayKlass*.
163 // It will use a reserved constant.
164 static traceid load_primitive(const oop mirror) {
165   assert(java_lang_Class::is_primitive(mirror), "invariant");
166   const Klass* const tak = java_lang_Class::array_klass_acquire(mirror);
167   traceid id;
168   if (tak == NULL) {
169     // The first klass id is reserved for the void.class
170     id = LAST_TYPE_ID + 1;
171   } else {
172     id = JfrTraceId::load_raw(tak) + 1;
173   }
174   JfrTraceIdEpoch::set_changed_tag_state();
175   return id;
176 }
177 
178 traceid JfrTraceId::load(jclass jc, bool raw /* false */) {
179   assert(jc != NULL, "invariant");
180   assert(JavaThread::current()->thread_state() == _thread_in_vm, "invariant");
181   const oop mirror = JNIHandles::resolve(jc);
182   assert(mirror != NULL, "invariant");
183   const Klass* const k = java_lang_Class::as_Klass(mirror);
184   return k != NULL ? (raw ? load_raw(k) : load(k)) : load_primitive(mirror);
185 }
186 
187 traceid JfrTraceId::load_raw(jclass jc) {
188   return load(jc, true);
189 }
190 
191 // used by CDS / APPCDS as part of "remove_unshareable_info"
192 void JfrTraceId::remove(const Klass* k) {
193   assert(k != NULL, "invariant");
194   // Mask off and store the event flags.
195   // This mechanism will retain the event specific flags
196   // in the archive, allowing for event flag restoration
197   // when renewing the traceid on klass revival.
198   k->set_trace_id(EVENT_KLASS_MASK(k));
199 }
200 
201 // used by CDS / APPCDS as part of "remove_unshareable_info"
202 void JfrTraceId::remove(const Method* method) {
203   assert(method != NULL, "invariant");
204   // Clear all bits.
205   method->set_trace_flags(0);
206 }
207 
208 // used by CDS / APPCDS as part of "restore_unshareable_info"
209 void JfrTraceId::restore(const Klass* k) {
210   assert(k != NULL, "invariant");
211   if (IS_JDK_JFR_EVENT_KLASS(k)) {
212     found_jdk_jfr_event_klass = true;
213   }
214   const traceid event_flags = k->trace_id();
215   // get a fresh traceid and restore the original event flags
216   k->set_trace_id(next_class_id() | event_flags);
217   if (k->is_typeArray_klass()) {
218     // the next id is reserved for the corresponding primitive class
219     next_class_id();
220   }
221 }
222 
223 bool JfrTraceId::in_visible_set(const jclass jc) {
224   assert(jc != NULL, "invariant");
225   assert(JavaThread::current()->thread_state() == _thread_in_vm, "invariant");
226   const oop mirror = JNIHandles::resolve(jc);
227   assert(mirror != NULL, "invariant");
228   return in_visible_set(java_lang_Class::as_Klass(mirror));
229 }
230 
231 bool JfrTraceId::in_jdk_jfr_event_hierarchy(const jclass jc) {
232   assert(jc != NULL, "invariant");
233   const oop mirror = JNIHandles::resolve(jc);
234   assert(mirror != NULL, "invariant");
235   return in_jdk_jfr_event_hierarchy(java_lang_Class::as_Klass(mirror));
236 }
237 
238 bool JfrTraceId::is_jdk_jfr_event_sub(const jclass jc) {
239   assert(jc != NULL, "invariant");
240   const oop mirror = JNIHandles::resolve(jc);
241   assert(mirror != NULL, "invariant");
242   return is_jdk_jfr_event_sub(java_lang_Class::as_Klass(mirror));
243 }
244 
245 bool JfrTraceId::is_jdk_jfr_event(const jclass jc) {
246   assert(jc != NULL, "invariant");
247   const oop mirror = JNIHandles::resolve(jc);
248   assert(mirror != NULL, "invariant");
249   return is_jdk_jfr_event(java_lang_Class::as_Klass(mirror));
250 }
251 
252 bool JfrTraceId::is_event_host(const jclass jc) {
253   assert(jc != NULL, "invariant");
254   const oop mirror = JNIHandles::resolve(jc);
255   assert(mirror != NULL, "invariant");
256   return is_event_host(java_lang_Class::as_Klass(mirror));
257 }
258 
259 void JfrTraceId::tag_as_jdk_jfr_event_sub(const jclass jc) {
260   assert(jc != NULL, "invariant");
261   const oop mirror = JNIHandles::resolve(jc);
262   assert(mirror != NULL, "invariant");
263   const Klass* const k = java_lang_Class::as_Klass(mirror);
264   tag_as_jdk_jfr_event_sub(k);
265   assert(IS_JDK_JFR_EVENT_SUBKLASS(k), "invariant");
266 }
267 
268 void JfrTraceId::tag_as_event_host(const jclass jc) {
269   assert(jc != NULL, "invariant");
270   const oop mirror = JNIHandles::resolve(jc);
271   assert(mirror != NULL, "invariant");
272   const Klass* const k = java_lang_Class::as_Klass(mirror);
273   tag_as_event_host(k);
274   assert(IS_EVENT_HOST_KLASS(k), "invariant");
275 }