1 /*
   2  * Copyright (c) 2011, 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/classLoaderData.inline.hpp"
  27 #include "classfile/symbolTable.hpp"
  28 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp"
  29 #include "jfr/utilities/jfrTypes.hpp"
  30 #include "oops/arrayKlass.inline.hpp"
  31 #include "oops/klass.inline.hpp"
  32 #include "oops/instanceKlass.inline.hpp"
  33 #include "oops/method.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "runtime/atomic.hpp"
  36 #include "runtime/vm_version.hpp"
  37 #include "runtime/jniHandles.inline.hpp"
  38 #include "runtime/thread.inline.hpp"
  39 #include "utilities/debug.hpp"
  40 
  41  // returns updated value
  42 static traceid atomic_inc(traceid volatile* const dest) {
  43   assert(VM_Version::supports_cx8(), "invariant");
  44   traceid compare_value;
  45   traceid exchange_value;
  46   do {
  47     compare_value = *dest;
  48     exchange_value = compare_value + 1;
  49   } while (Atomic::cmpxchg(exchange_value, dest, compare_value) != compare_value);
  50   return exchange_value;
  51 }
  52 
  53 static traceid next_class_id() {
  54   static volatile traceid class_id_counter = MaxJfrEventId + 100;
  55   return atomic_inc(&class_id_counter) << TRACE_ID_SHIFT;
  56 }
  57 
  58 static traceid next_thread_id() {
  59   static volatile traceid thread_id_counter = 0;
  60   return atomic_inc(&thread_id_counter);
  61 }
  62 
  63 static traceid next_module_id() {
  64   static volatile traceid module_id_counter = 1;
  65   return atomic_inc(&module_id_counter) << TRACE_ID_SHIFT;
  66 }
  67 
  68 static traceid next_package_id() {
  69   static volatile traceid package_id_counter = 1;
  70   return atomic_inc(&package_id_counter) << TRACE_ID_SHIFT;
  71 }
  72 
  73 static traceid next_class_loader_data_id() {
  74   static volatile traceid cld_id_counter = 1;
  75   return atomic_inc(&cld_id_counter) << TRACE_ID_SHIFT;
  76 }
  77 
  78 static bool found_jdk_internal_event_klass = false;
  79 static bool found_jdk_jfr_event_klass = false;
  80 
  81 static void check_klass(const Klass* klass) {
  82   assert(klass != NULL, "invariant");
  83   if (found_jdk_internal_event_klass && found_jdk_jfr_event_klass) {
  84     return;
  85   }
  86   static const Symbol* jdk_internal_event_sym = NULL;
  87   if (jdk_internal_event_sym == NULL) {
  88     // setup when loading the first TypeArrayKlass (Universe::genesis) hence single threaded invariant
  89     jdk_internal_event_sym = SymbolTable::new_permanent_symbol("jdk/internal/event/Event");
  90   }
  91   assert(jdk_internal_event_sym != NULL, "invariant");
  92 
  93   static const Symbol* jdk_jfr_event_sym = NULL;
  94   if (jdk_jfr_event_sym == NULL) {
  95     // setup when loading the first TypeArrayKlass (Universe::genesis) hence single threaded invariant
  96     jdk_jfr_event_sym = SymbolTable::new_permanent_symbol("jdk/jfr/Event");
  97   }
  98   assert(jdk_jfr_event_sym != NULL, "invariant");
  99   const Symbol* const klass_name = klass->name();
 100 
 101   if (!found_jdk_internal_event_klass) {
 102     if (jdk_internal_event_sym == klass_name && klass->class_loader() == NULL) {
 103       found_jdk_internal_event_klass = true;
 104       JfrTraceId::tag_as_jdk_jfr_event(klass);
 105       return;
 106     }
 107   }
 108 
 109   if (!found_jdk_jfr_event_klass) {
 110     if (jdk_jfr_event_sym == klass_name && klass->class_loader() == NULL) {
 111       found_jdk_jfr_event_klass = true;
 112       JfrTraceId::tag_as_jdk_jfr_event(klass);
 113       return;
 114     }
 115   }
 116 }
 117 
 118 void JfrTraceId::assign(const Klass* klass) {
 119   assert(klass != NULL, "invariant");
 120   klass->set_trace_id(next_class_id());
 121   check_klass(klass);
 122   const Klass* const super = klass->super();
 123   if (super == NULL) {
 124     return;
 125   }
 126   if (IS_EVENT_KLASS(super)) {
 127     tag_as_jdk_jfr_event_sub(klass);
 128   }
 129 }
 130 
 131 void JfrTraceId::assign(const ModuleEntry* module) {
 132   assert(module != NULL, "invariant");
 133   module->set_trace_id(next_module_id());
 134 }
 135 
 136 void JfrTraceId::assign(const PackageEntry* package) {
 137   assert(package != NULL, "invariant");
 138   package->set_trace_id(next_package_id());
 139 }
 140 
 141 void JfrTraceId::assign(const ClassLoaderData* cld) {
 142   assert(cld != NULL, "invariant");
 143   if (cld->is_unsafe_anonymous()) {
 144     cld->set_trace_id(0);
 145     return;
 146   }
 147   cld->set_trace_id(next_class_loader_data_id());
 148 }
 149 
 150 traceid JfrTraceId::assign_thread_id() {
 151   return next_thread_id();
 152 }
 153 
 154 // used by CDS / APPCDS as part of "remove_unshareable_info"
 155 void JfrTraceId::remove(const Klass* k) {
 156   assert(k != NULL, "invariant");
 157   // Mask off and store the event flags.
 158   // This mechanism will retain the event specific flags
 159   // in the archive, allowing for event flag restoration
 160   // when renewing the traceid on klass revival.
 161   k->set_trace_id(EVENT_KLASS_MASK(k));
 162 }
 163 
 164 // used by CDS / APPCDS as part of "restore_unshareable_info"
 165 void JfrTraceId::restore(const Klass* k) {
 166   assert(k != NULL, "invariant");
 167   if (IS_JDK_JFR_EVENT_KLASS(k)) {
 168     found_jdk_jfr_event_klass = true;
 169   }
 170   const traceid event_flags = k->trace_id();
 171   // get a fresh traceid and restore the original event flags
 172   k->set_trace_id(next_class_id() | event_flags);
 173 }
 174 
 175 traceid JfrTraceId::get(jclass jc) {
 176   assert(jc != NULL, "invariant");
 177   assert(((JavaThread*)Thread::current())->thread_state() == _thread_in_vm, "invariant");
 178   const oop my_oop = JNIHandles::resolve(jc);
 179   assert(my_oop != NULL, "invariant");
 180   return get(java_lang_Class::as_Klass(my_oop));
 181 }
 182 
 183 traceid JfrTraceId::use(jclass jc) {
 184   assert(jc != NULL, "invariant");
 185   assert(((JavaThread*)Thread::current())->thread_state() == _thread_in_vm, "invariant");
 186   const oop my_oop = JNIHandles::resolve(jc);
 187   assert(my_oop != NULL, "invariant");
 188   return use(java_lang_Class::as_Klass(my_oop));
 189 }
 190 
 191 bool JfrTraceId::in_visible_set(const jclass jc) {
 192   assert(jc != NULL, "invariant");
 193   assert(((JavaThread*)Thread::current())->thread_state() == _thread_in_vm, "invariant");
 194   const oop mirror = JNIHandles::resolve(jc);
 195   assert(mirror != NULL, "invariant");
 196   return in_visible_set(java_lang_Class::as_Klass(mirror));
 197 }
 198 
 199 bool JfrTraceId::in_jdk_jfr_event_hierarchy(const jclass jc) {
 200   assert(jc != NULL, "invariant");
 201   const oop mirror = JNIHandles::resolve(jc);
 202   assert(mirror != NULL, "invariant");
 203   return in_jdk_jfr_event_hierarchy(java_lang_Class::as_Klass(mirror));
 204 }
 205 
 206 bool JfrTraceId::is_jdk_jfr_event_sub(const jclass jc) {
 207   assert(jc != NULL, "invariant");
 208   const oop mirror = JNIHandles::resolve(jc);
 209   assert(mirror != NULL, "invariant");
 210   return is_jdk_jfr_event_sub(java_lang_Class::as_Klass(mirror));
 211 }
 212 
 213 bool JfrTraceId::is_jdk_jfr_event(const jclass jc) {
 214   assert(jc != NULL, "invariant");
 215   const oop mirror = JNIHandles::resolve(jc);
 216   assert(mirror != NULL, "invariant");
 217   return is_jdk_jfr_event(java_lang_Class::as_Klass(mirror));
 218 }
 219 
 220 bool JfrTraceId::is_event_host(const jclass jc) {
 221   assert(jc != NULL, "invariant");
 222   const oop mirror = JNIHandles::resolve(jc);
 223   assert(mirror != NULL, "invariant");
 224   return is_event_host(java_lang_Class::as_Klass(mirror));
 225 }
 226 
 227 void JfrTraceId::tag_as_jdk_jfr_event_sub(const jclass jc) {
 228   assert(jc != NULL, "invariant");
 229   const oop mirror = JNIHandles::resolve(jc);
 230   assert(mirror != NULL, "invariant");
 231   const Klass* const k = java_lang_Class::as_Klass(mirror);
 232   tag_as_jdk_jfr_event_sub(k);
 233   assert(IS_JDK_JFR_EVENT_SUBKLASS(k), "invariant");
 234 }
 235 
 236 void JfrTraceId::tag_as_event_host(const jclass jc) {
 237   assert(jc != NULL, "invariant");
 238   const oop mirror = JNIHandles::resolve(jc);
 239   assert(mirror != NULL, "invariant");
 240   const Klass* const k = java_lang_Class::as_Klass(mirror);
 241   tag_as_event_host(k);
 242   assert(IS_EVENT_HOST_KLASS(k), "invariant");
 243 }