1 /*
   2  * Copyright (c) 1997, 2026, 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 "cds/aotClassLocation.hpp"
  26 #include "cds/cds_globals.hpp"
  27 #include "cds/cdsConfig.hpp"
  28 #include "cds/dynamicArchive.hpp"
  29 #include "cds/heapShared.hpp"
  30 #include "classfile/classFileStream.hpp"
  31 #include "classfile/classLoader.inline.hpp"
  32 #include "classfile/classLoaderData.inline.hpp"
  33 #include "classfile/classLoadInfo.hpp"
  34 #include "classfile/javaClasses.hpp"
  35 #include "classfile/klassFactory.hpp"
  36 #include "classfile/moduleEntry.hpp"
  37 #include "classfile/modules.hpp"
  38 #include "classfile/packageEntry.hpp"
  39 #include "classfile/symbolTable.hpp"
  40 #include "classfile/systemDictionary.hpp"
  41 #include "classfile/systemDictionaryShared.hpp"
  42 #include "classfile/vmClasses.hpp"
  43 #include "classfile/vmSymbols.hpp"
  44 #include "compiler/compileBroker.hpp"
  45 #include "cppstdlib/cstdlib.hpp"
  46 #include "interpreter/bytecodeStream.hpp"
  47 #include "interpreter/oopMapCache.hpp"
  48 #include "jimage.hpp"
  49 #include "jvm.h"
  50 #include "logging/log.hpp"
  51 #include "logging/logStream.hpp"
  52 #include "logging/logTag.hpp"
  53 #include "memory/allocation.inline.hpp"
  54 #include "memory/oopFactory.hpp"
  55 #include "memory/resourceArea.hpp"
  56 #include "memory/universe.hpp"
  57 #include "oops/instanceKlass.hpp"
  58 #include "oops/instanceRefKlass.hpp"
  59 #include "oops/klass.inline.hpp"
  60 #include "oops/method.inline.hpp"
  61 #include "oops/objArrayOop.inline.hpp"
  62 #include "oops/oop.inline.hpp"
  63 #include "oops/symbol.hpp"
  64 #include "prims/jvm_misc.hpp"
  65 #include "runtime/arguments.hpp"
  66 #include "runtime/handles.inline.hpp"
  67 #include "runtime/init.hpp"
  68 #include "runtime/interfaceSupport.inline.hpp"
  69 #include "runtime/java.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/os.hpp"
  72 #include "runtime/perfData.hpp"
  73 #include "runtime/timer.hpp"
  74 #include "runtime/vm_version.hpp"
  75 #include "services/management.hpp"
  76 #include "services/threadService.hpp"
  77 #include "utilities/checkedCast.hpp"
  78 #include "utilities/classpathStream.hpp"
  79 #include "utilities/events.hpp"
  80 #include "utilities/macros.hpp"
  81 #include "utilities/ostream.hpp"
  82 #include "utilities/utf8.hpp"
  83 
  84 #include <ctype.h>
  85 
  86 // Entry point in java.dll for path canonicalization
  87 
  88 typedef int (*canonicalize_fn_t)(const char *orig, char *out, int len);
  89 
  90 static canonicalize_fn_t CanonicalizeEntry  = nullptr;
  91 
  92 // Entry points for jimage.dll for loading jimage file entries
  93 
  94 static JImageOpen_t                    JImageOpen             = nullptr;
  95 static JImageClose_t                   JImageClose            = nullptr;
  96 static JImageFindResource_t            JImageFindResource     = nullptr;
  97 static JImageGetResource_t             JImageGetResource      = nullptr;
  98 
  99 // JimageFile pointer, or null if exploded JDK build.
 100 static JImageFile*                     JImage_file            = nullptr;
 101 
 102 // Globals
 103 
 104 PerfCounter*    ClassLoader::_perf_accumulated_time = nullptr;
 105 PerfCounter*    ClassLoader::_perf_classes_inited = nullptr;
 106 PerfCounter*    ClassLoader::_perf_class_init_time = nullptr;
 107 PerfCounter*    ClassLoader::_perf_class_init_selftime = nullptr;
 108 PerfCounter*    ClassLoader::_perf_classes_verified = nullptr;
 109 PerfCounter*    ClassLoader::_perf_class_verify_time = nullptr;
 110 PerfCounter*    ClassLoader::_perf_class_verify_selftime = nullptr;
 111 PerfCounter*    ClassLoader::_perf_classes_linked = nullptr;
 112 PerfCounter*    ClassLoader::_perf_class_link_time = nullptr;
 113 PerfCounter*    ClassLoader::_perf_class_link_selftime = nullptr;
 114 PerfCounter*    ClassLoader::_perf_shared_classload_time = nullptr;
 115 PerfCounter*    ClassLoader::_perf_sys_classload_time = nullptr;
 116 PerfCounter*    ClassLoader::_perf_app_classload_time = nullptr;
 117 PerfCounter*    ClassLoader::_perf_app_classload_selftime = nullptr;
 118 PerfCounter*    ClassLoader::_perf_app_classload_count = nullptr;
 119 PerfCounter*    ClassLoader::_perf_define_appclasses = nullptr;
 120 PerfCounter*    ClassLoader::_perf_define_appclass_time = nullptr;
 121 PerfCounter*    ClassLoader::_perf_define_appclass_selftime = nullptr;
 122 PerfCounter*    ClassLoader::_perf_app_classfile_bytes_read = nullptr;
 123 PerfCounter*    ClassLoader::_perf_sys_classfile_bytes_read = nullptr;
 124 PerfCounter*    ClassLoader::_perf_ik_link_methods_time = nullptr;
 125 PerfCounter*    ClassLoader::_perf_method_adapters_time = nullptr;
 126 PerfCounter*    ClassLoader::_perf_ik_link_methods_count = nullptr;
 127 PerfCounter*    ClassLoader::_perf_method_adapters_count = nullptr;
 128 PerfCounter*    ClassLoader::_unsafe_defineClassCallCounter = nullptr;
 129 PerfCounter*    ClassLoader::_perf_secondary_hash_time = nullptr;
 130 PerfCounter*    ClassLoader::_perf_change_wx_time = nullptr;
 131 
 132 PerfCounter*    ClassLoader::_perf_resolve_indy_time = nullptr;
 133 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_time = nullptr;
 134 PerfCounter*    ClassLoader::_perf_resolve_mh_time = nullptr;
 135 PerfCounter*    ClassLoader::_perf_resolve_mt_time = nullptr;
 136 
 137 PerfCounter*    ClassLoader::_perf_resolve_indy_count = nullptr;
 138 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_count = nullptr;
 139 PerfCounter*    ClassLoader::_perf_resolve_mh_count = nullptr;
 140 PerfCounter*    ClassLoader::_perf_resolve_mt_count = nullptr;
 141 
 142 void ClassLoader::print_counters(outputStream *st) {
 143   st->print_cr("ClassLoader:");
 144   st->print_cr("  clinit:               " JLONG_FORMAT "ms / " JLONG_FORMAT " events", ClassLoader::class_init_time_ms(), ClassLoader::class_init_count());
 145   st->print_cr("  link methods:         " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_ik_link_methods_time->get_value())   , _perf_ik_link_methods_count->get_value());
 146   st->print_cr("  method adapters:      " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_method_adapters_time->get_value())   , _perf_method_adapters_count->get_value());
 147   st->print_cr("  resolve...");
 148   st->print_cr("    invokedynamic:   " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_indy_time->get_value())         , _perf_resolve_indy_count->get_value());
 149   st->print_cr("    invokehandle:    " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_invokehandle_time->get_value()) , _perf_resolve_invokehandle_count->get_value());
 150   st->print_cr("    CP_MethodHandle: " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_mh_time->get_value())           , _perf_resolve_mh_count->get_value());
 151   st->print_cr("    CP_MethodType:   " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_mt_time->get_value())           , _perf_resolve_mt_count->get_value());
 152   st->cr();
 153 }
 154 
 155 GrowableArray<ModuleClassPathList*>* ClassLoader::_patch_mod_entries = nullptr;
 156 GrowableArray<ModuleClassPathList*>* ClassLoader::_exploded_entries = nullptr;
 157 ClassPathEntry* ClassLoader::_jrt_entry = nullptr;
 158 
 159 ClassPathEntry* volatile ClassLoader::_first_append_entry_list = nullptr;
 160 ClassPathEntry* volatile ClassLoader::_last_append_entry  = nullptr;
 161 
 162 // helper routines
 163 #if INCLUDE_CDS
 164 static bool string_starts_with(const char* str, const char* str_to_find) {
 165   size_t str_len = strlen(str);
 166   size_t str_to_find_len = strlen(str_to_find);
 167   if (str_to_find_len > str_len) {
 168     return false;
 169   }
 170   return (strncmp(str, str_to_find, str_to_find_len) == 0);
 171 }
 172 #endif
 173 
 174 static const char* get_jimage_version_string() {
 175   static char version_string[10] = "";
 176   if (version_string[0] == '\0') {
 177     jio_snprintf(version_string, sizeof(version_string), "%d.%d",
 178                  VM_Version::vm_major_version(), VM_Version::vm_minor_version());
 179   }
 180   return (const char*)version_string;
 181 }
 182 
 183 bool ClassLoader::string_ends_with(const char* str, const char* str_to_find) {
 184   size_t str_len = strlen(str);
 185   size_t str_to_find_len = strlen(str_to_find);
 186   if (str_to_find_len > str_len) {
 187     return false;
 188   }
 189   return (strncmp(str + (str_len - str_to_find_len), str_to_find, str_to_find_len) == 0);
 190 }
 191 
 192 // Used to obtain the package name from a fully qualified class name.
 193 Symbol* ClassLoader::package_from_class_name(const Symbol* name, bool* bad_class_name) {
 194   if (name == nullptr) {
 195     if (bad_class_name != nullptr) {
 196       *bad_class_name = true;
 197     }
 198     return nullptr;
 199   }
 200 
 201   int utf_len = name->utf8_length();
 202   const jbyte* base = (const jbyte*)name->base();
 203   const jbyte* start = base;
 204   const jbyte* end = UTF8::strrchr(start, utf_len, JVM_SIGNATURE_SLASH);
 205   if (end == nullptr) {
 206     return nullptr;
 207   }
 208   // Skip over '['s
 209   if (*start == JVM_SIGNATURE_ARRAY) {
 210     do {
 211       start++;
 212     } while (start < end && *start == JVM_SIGNATURE_ARRAY);
 213 
 214     // Fully qualified class names should not contain a 'L'.
 215     // Set bad_class_name to true to indicate that the package name
 216     // could not be obtained due to an error condition.
 217     // In this situation, is_same_class_package returns false.
 218     if (*start == JVM_SIGNATURE_CLASS) {
 219       if (bad_class_name != nullptr) {
 220         *bad_class_name = true;
 221       }
 222       return nullptr;
 223     }
 224   }
 225   // A class name could have just the slash character in the name,
 226   // in which case start > end
 227   if (start >= end) {
 228     // No package name
 229     if (bad_class_name != nullptr) {
 230       *bad_class_name = true;
 231     }
 232     return nullptr;
 233   }
 234   return SymbolTable::new_symbol(name, pointer_delta_as_int(start, base), pointer_delta_as_int(end, base));
 235 }
 236 
 237 // Given a fully qualified package name, find its defining package in the class loader's
 238 // package entry table.
 239 PackageEntry* ClassLoader::get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data) {
 240   if (pkg_name == nullptr) {
 241     return nullptr;
 242   }
 243   PackageEntryTable* pkgEntryTable = loader_data->packages();
 244   return pkgEntryTable->lookup_only(pkg_name);
 245 }
 246 
 247 const char* ClassPathEntry::copy_path(const char* path) {
 248   char* copy = NEW_C_HEAP_ARRAY(char, strlen(path)+1, mtClass);
 249   strcpy(copy, path);
 250   return copy;
 251 }
 252 
 253 ClassPathDirEntry::~ClassPathDirEntry() {
 254   FREE_C_HEAP_ARRAY(char, _dir);
 255 }
 256 
 257 ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char* name) {
 258   // construct full path name
 259   assert((_dir != nullptr) && (name != nullptr), "sanity");
 260   size_t path_len = strlen(_dir) + strlen(name) + strlen(os::file_separator()) + 1;
 261   char* path = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, path_len);
 262   int len = jio_snprintf(path, path_len, "%s%s%s", _dir, os::file_separator(), name);
 263   assert(len == (int)(path_len - 1), "sanity");
 264   // check if file exists
 265   struct stat st;
 266   if (os::stat(path, &st) == 0) {
 267     // found file, open it
 268     int file_handle = os::open(path, 0, 0);
 269     if (file_handle != -1) {
 270       // read contents into resource array
 271       u1* buffer = NEW_RESOURCE_ARRAY_IN_THREAD(current, u1, st.st_size);
 272       size_t num_read = ::read(file_handle, (char*) buffer, st.st_size);
 273       // close file
 274       ::close(file_handle);
 275       // construct ClassFileStream
 276       if (num_read == (size_t)st.st_size) {
 277         if (UsePerfData) {
 278           ClassLoader::perf_sys_classfile_bytes_read()->inc(num_read);
 279         }
 280 #ifdef ASSERT
 281         // Freeing path is a no-op here as buffer prevents it from being reclaimed. But we keep it for
 282         // debug builds so that we guard against use-after-free bugs.
 283         FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 284 #endif
 285         // We don't verify the length of the classfile stream fits in an int, but this is the
 286         // bootloader so we have control of this.
 287         // Resource allocated
 288         return new ClassFileStream(buffer,
 289                                    checked_cast<int>(st.st_size),
 290                                    _dir);
 291       }
 292     }
 293   }
 294   FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 295   return nullptr;
 296 }
 297 
 298 ClassPathZipEntry::ClassPathZipEntry(jzfile* zip, const char* zip_name) : ClassPathEntry() {
 299   _zip = zip;
 300   _zip_name = copy_path(zip_name);
 301 }
 302 
 303 ClassPathZipEntry::~ClassPathZipEntry() {
 304   ZipLibrary::close(_zip);
 305   FREE_C_HEAP_ARRAY(char, _zip_name);
 306 }
 307 
 308 bool ClassPathZipEntry::has_entry(JavaThread* current, const char* name) {
 309   ThreadToNativeFromVM ttn(current);
 310   // check whether zip archive contains name
 311   jint name_len;
 312   jint filesize;
 313   jzentry* entry = ZipLibrary::find_entry(_zip, name, &filesize, &name_len);
 314   if (entry == nullptr) {
 315     return false;
 316   } else {
 317      ZipLibrary::free_entry(_zip, entry);
 318     return true;
 319   }
 320 }
 321 
 322 u1* ClassPathZipEntry::open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate) {
 323   // enable call to C land
 324   ThreadToNativeFromVM ttn(current);
 325   // check whether zip archive contains name
 326   jint name_len;
 327   jzentry* entry = ZipLibrary::find_entry(_zip, name, filesize, &name_len);
 328   if (entry == nullptr) return nullptr;
 329   u1* buffer;
 330   char name_buf[128];
 331   char* filename;
 332   if (name_len < 128) {
 333     filename = name_buf;
 334   } else {
 335     filename = NEW_RESOURCE_ARRAY(char, name_len + 1);
 336   }
 337 
 338   // read contents into resource array
 339   size_t size = (uint32_t)(*filesize);
 340   if (nul_terminate) {
 341     if (sizeof(size) == sizeof(uint32_t) && size == UINT_MAX) {
 342       return nullptr; // 32-bit integer overflow will occur.
 343     }
 344     size++;
 345   }
 346   buffer = NEW_RESOURCE_ARRAY(u1, size);
 347   if (!ZipLibrary::read_entry(_zip, entry, buffer, filename)) {
 348     return nullptr;
 349   }
 350 
 351   // return result
 352   if (nul_terminate) {
 353     buffer[size - 1] = 0;
 354   }
 355   return buffer;
 356 }
 357 
 358 ClassFileStream* ClassPathZipEntry::open_stream(JavaThread* current, const char* name) {
 359   jint filesize;
 360   u1* buffer = open_entry(current, name, &filesize, false);
 361   if (buffer == nullptr) {
 362     return nullptr;
 363   }
 364   if (UsePerfData) {
 365     ClassLoader::perf_sys_classfile_bytes_read()->inc(filesize);
 366   }
 367   // Resource allocated
 368   return new ClassFileStream(buffer,
 369                              filesize,
 370                              _zip_name);
 371 }
 372 
 373 DEBUG_ONLY(ClassPathImageEntry* ClassPathImageEntry::_singleton = nullptr;)
 374 
 375 JImageFile* ClassPathImageEntry::jimage() const {
 376   return JImage_file;
 377 }
 378 
 379 JImageFile* ClassPathImageEntry::jimage_non_null() const {
 380   assert(ClassLoader::has_jrt_entry(), "must be");
 381   assert(jimage() != nullptr, "should have been opened by ClassLoader::lookup_vm_options "
 382                            "and remained throughout normal JVM lifetime");
 383   return jimage();
 384 }
 385 
 386 void ClassPathImageEntry::close_jimage() {
 387   if (jimage() != nullptr) {
 388     (*JImageClose)(jimage());
 389     JImage_file = nullptr;
 390   }
 391 }
 392 
 393 ClassPathImageEntry::ClassPathImageEntry(JImageFile* jimage, const char* name) :
 394   ClassPathEntry() {
 395   guarantee(jimage != nullptr, "jimage file is null");
 396   guarantee(name != nullptr, "jimage file name is null");
 397   assert(_singleton == nullptr, "VM supports only one jimage");
 398   DEBUG_ONLY(_singleton = this);
 399   size_t len = strlen(name) + 1;
 400   _name = copy_path(name);
 401 }
 402 
 403 ClassFileStream* ClassPathImageEntry::open_stream(JavaThread* current, const char* name) {
 404   return open_stream_for_loader(current, name, ClassLoaderData::the_null_class_loader_data());
 405 }
 406 
 407 // For a class in a named module, look it up in the jimage file using this syntax:
 408 //    /<module-name>/<package-name>/<base-class>
 409 //
 410 // Assumptions:
 411 //     1. There are no unnamed modules in the jimage file.
 412 //     2. A package is in at most one module in the jimage file.
 413 //
 414 ClassFileStream* ClassPathImageEntry::open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) {
 415   jlong size;
 416   JImageLocationRef location = 0;
 417 
 418   TempNewSymbol class_name = SymbolTable::new_symbol(name);
 419   TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
 420 
 421   if (pkg_name != nullptr) {
 422     if (!Universe::is_module_initialized()) {
 423       location = (*JImageFindResource)(jimage_non_null(), JAVA_BASE_NAME, get_jimage_version_string(), name, &size);
 424     } else {
 425       PackageEntry* package_entry = ClassLoader::get_package_entry(pkg_name, loader_data);
 426       if (package_entry != nullptr) {
 427         ResourceMark rm(current);
 428         // Get the module name
 429         ModuleEntry* module = package_entry->module();
 430         assert(module != nullptr, "Boot classLoader package missing module");
 431         assert(module->is_named(), "Boot classLoader package is in unnamed module");
 432         const char* module_name = module->name()->as_C_string();
 433         if (module_name != nullptr) {
 434           location = (*JImageFindResource)(jimage_non_null(), module_name, get_jimage_version_string(), name, &size);
 435         }
 436       }
 437     }
 438   }
 439 
 440   if (location != 0) {
 441     if (UsePerfData) {
 442       ClassLoader::perf_sys_classfile_bytes_read()->inc(size);
 443     }
 444     char* data = NEW_RESOURCE_ARRAY(char, size);
 445     (*JImageGetResource)(jimage_non_null(), location, data, size);
 446     // Resource allocated
 447     assert(this == (ClassPathImageEntry*)ClassLoader::get_jrt_entry(), "must be");
 448     return new ClassFileStream((u1*)data,
 449                                checked_cast<int>(size),
 450                                _name,
 451                                true); // from_boot_loader_modules_image
 452   }
 453 
 454   return nullptr;
 455 }
 456 
 457 JImageLocationRef ClassLoader::jimage_find_resource(JImageFile* jf,
 458                                                     const char* module_name,
 459                                                     const char* file_name,
 460                                                     jlong &size) {
 461   return ((*JImageFindResource)(jf, module_name, get_jimage_version_string(), file_name, &size));
 462 }
 463 
 464 bool ClassPathImageEntry::is_modules_image() const {
 465   assert(this == _singleton, "VM supports a single jimage");
 466   assert(this == (ClassPathImageEntry*)ClassLoader::get_jrt_entry(), "must be used for jrt entry");
 467   return true;
 468 }
 469 
 470 ModuleClassPathList::ModuleClassPathList(Symbol* module_name) {
 471   _module_name = module_name;
 472   _module_first_entry = nullptr;
 473   _module_last_entry = nullptr;
 474 }
 475 
 476 ModuleClassPathList::~ModuleClassPathList() {
 477   // Clean out each ClassPathEntry on list
 478   ClassPathEntry* e = _module_first_entry;
 479   while (e != nullptr) {
 480     ClassPathEntry* next_entry = e->next();
 481     delete e;
 482     e = next_entry;
 483   }
 484 }
 485 
 486 void ModuleClassPathList::add_to_list(ClassPathEntry* new_entry) {
 487   if (new_entry != nullptr) {
 488     if (_module_last_entry == nullptr) {
 489       _module_first_entry = _module_last_entry = new_entry;
 490     } else {
 491       _module_last_entry->set_next(new_entry);
 492       _module_last_entry = new_entry;
 493     }
 494   }
 495 }
 496 
 497 void ClassLoader::trace_class_path(const char* msg, const char* name) {
 498   LogTarget(Info, class, path) lt;
 499   if (lt.is_enabled()) {
 500     LogStream ls(lt);
 501     if (msg) {
 502       ls.print("%s", msg);
 503     }
 504     if (name) {
 505       if (strlen(name) < 256) {
 506         ls.print("%s", name);
 507       } else {
 508         // For very long paths, we need to print each character separately,
 509         // as print_cr() has a length limit
 510         while (name[0] != '\0') {
 511           ls.print("%c", name[0]);
 512           name++;
 513         }
 514       }
 515     }
 516     ls.cr();
 517   }
 518 }
 519 
 520 void ClassLoader::setup_bootstrap_search_path(JavaThread* current) {
 521   const char* bootcp = Arguments::get_boot_class_path();
 522   assert(bootcp != nullptr, "Boot class path must not be nullptr");
 523   if (PrintSharedArchiveAndExit) {
 524     // Don't print bootcp - this is the bootcp of this current VM process, not necessarily
 525     // the same as the boot classpath of the shared archive.
 526   } else {
 527     trace_class_path("bootstrap loader class path=", bootcp);
 528   }
 529   setup_bootstrap_search_path_impl(current, bootcp);
 530 }
 531 
 532 void ClassLoader::close_jrt_image() {
 533   // Not applicable for exploded builds
 534   if (!ClassLoader::has_jrt_entry()) return;
 535   _jrt_entry->close_jimage();
 536 }
 537 
 538 // Construct the array of module/path pairs as specified to --patch-module
 539 // for the boot loader to search ahead of the jimage, if the class being
 540 // loaded is defined to a module that has been specified to --patch-module.
 541 void ClassLoader::setup_patch_mod_entries() {
 542   JavaThread* current = JavaThread::current();
 543   GrowableArray<ModulePatchPath*>* patch_mod_args = Arguments::get_patch_mod_prefix();
 544   int num_of_entries = patch_mod_args->length();
 545 
 546   // Set up the boot loader's _patch_mod_entries list
 547   _patch_mod_entries = new (mtModule) GrowableArray<ModuleClassPathList*>(num_of_entries, mtModule);
 548 
 549   for (int i = 0; i < num_of_entries; i++) {
 550     const char* module_name = (patch_mod_args->at(i))->module_name();
 551     Symbol* const module_sym = SymbolTable::new_symbol(module_name);
 552     assert(module_sym != nullptr, "Failed to obtain Symbol for module name");
 553     ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 554 
 555     char* class_path = (patch_mod_args->at(i))->path_string();
 556     ResourceMark rm(current);
 557     ClasspathStream cp_stream(class_path);
 558 
 559     while (cp_stream.has_next()) {
 560       const char* path = cp_stream.get_next();
 561       struct stat st;
 562       if (os::stat(path, &st) == 0) {
 563         // File or directory found
 564         ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);
 565         // If the path specification is valid, enter it into this module's list
 566         if (new_entry != nullptr) {
 567           module_cpl->add_to_list(new_entry);
 568         }
 569       }
 570     }
 571 
 572     // Record the module into the list of --patch-module entries only if
 573     // valid ClassPathEntrys have been created
 574     if (module_cpl->module_first_entry() != nullptr) {
 575       _patch_mod_entries->push(module_cpl);
 576     }
 577   }
 578 }
 579 
 580 // Determine whether the module has been patched via the command-line
 581 // option --patch-module
 582 bool ClassLoader::is_in_patch_mod_entries(Symbol* module_name) {
 583   if (_patch_mod_entries != nullptr && _patch_mod_entries->is_nonempty()) {
 584     int table_len = _patch_mod_entries->length();
 585     for (int i = 0; i < table_len; i++) {
 586       ModuleClassPathList* patch_mod = _patch_mod_entries->at(i);
 587       if (module_name->fast_compare(patch_mod->module_name()) == 0) {
 588         return true;
 589       }
 590     }
 591   }
 592   return false;
 593 }
 594 
 595 // Set up the _jrt_entry if present and boot append path
 596 void ClassLoader::setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path) {
 597   ResourceMark rm(current);
 598   ClasspathStream cp_stream(class_path);
 599   bool set_base_piece = true;
 600 
 601 #if INCLUDE_CDS
 602   if (CDSConfig::is_dumping_archive()) {
 603     if (!Arguments::has_jimage()) {
 604       vm_exit_during_initialization("CDS is not supported in exploded JDK build", nullptr);
 605     }
 606   }
 607 #endif
 608 
 609   while (cp_stream.has_next()) {
 610     const char* path = cp_stream.get_next();
 611 
 612     if (set_base_piece) {
 613       // The first time through the bootstrap_search setup, it must be determined
 614       // what the base or core piece of the boot loader search is.  Either a java runtime
 615       // image is present or this is an exploded module build situation.
 616       assert(string_ends_with(path, MODULES_IMAGE_NAME) || string_ends_with(path, JAVA_BASE_NAME),
 617              "Incorrect boot loader search path, no java runtime image or " JAVA_BASE_NAME " exploded build");
 618       struct stat st;
 619       if (os::stat(path, &st) == 0) {
 620         // Directory found
 621         if (JImage_file != nullptr) {
 622           assert(Arguments::has_jimage(), "sanity check");
 623           const char* canonical_path = get_canonical_path(path, current);
 624           assert(canonical_path != nullptr, "canonical_path issue");
 625 
 626           _jrt_entry = new ClassPathImageEntry(JImage_file, canonical_path);
 627           assert(_jrt_entry != nullptr && _jrt_entry->is_modules_image(), "No java runtime image present");
 628           assert(_jrt_entry->jimage() != nullptr, "No java runtime image");
 629         } // else it's an exploded build.
 630       } else {
 631         // If path does not exist, exit
 632         vm_exit_during_initialization("Unable to establish the boot loader search path", path);
 633       }
 634       set_base_piece = false;
 635     } else {
 636       // Every entry on the boot class path after the initial base piece,
 637       // which is set by os::set_boot_path(), is considered an appended entry.
 638       update_class_path_entry_list(current, path);
 639     }
 640   }
 641 }
 642 
 643 // Gets the exploded path for the named module. The memory for the path
 644 // is allocated on the C heap if `c_heap` is true otherwise in the resource area.
 645 static const char* get_exploded_module_path(const char* module_name, bool c_heap) {
 646   const char *home = Arguments::get_java_home();
 647   const char file_sep = os::file_separator()[0];
 648   // 10 represents the length of "modules" + 2 file separators + \0
 649   size_t len = strlen(home) + strlen(module_name) + 10;
 650   char *path = c_heap ? NEW_C_HEAP_ARRAY(char, len, mtModule) : NEW_RESOURCE_ARRAY(char, len);
 651   jio_snprintf(path, len, "%s%cmodules%c%s", home, file_sep, file_sep, module_name);
 652   return path;
 653 }
 654 
 655 // During an exploded modules build, each module defined to the boot loader
 656 // will be added to the ClassLoader::_exploded_entries array.
 657 void ClassLoader::add_to_exploded_build_list(JavaThread* current, Symbol* module_sym) {
 658   assert(!ClassLoader::has_jrt_entry(), "Exploded build not applicable");
 659   assert(_exploded_entries != nullptr, "_exploded_entries was not initialized");
 660 
 661   // Find the module's symbol
 662   ResourceMark rm(current);
 663   const char *module_name = module_sym->as_C_string();
 664   const char *path = get_exploded_module_path(module_name, false);
 665 
 666   struct stat st;
 667   if (os::stat(path, &st) == 0) {
 668     // Directory found
 669     ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);
 670 
 671     // If the path specification is valid, enter it into this module's list.
 672     // There is no need to check for duplicate modules in the exploded entry list,
 673     // since no two modules with the same name can be defined to the boot loader.
 674     // This is checked at module definition time in Modules::define_module.
 675     if (new_entry != nullptr) {
 676       ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 677       module_cpl->add_to_list(new_entry);
 678       {
 679         MutexLocker ml(current, Module_lock);
 680         _exploded_entries->push(module_cpl);
 681       }
 682       log_info(class, load)("path: %s", path);
 683     }
 684   }
 685 }
 686 
 687 jzfile* ClassLoader::open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread) {
 688   // enable call to C land
 689   ThreadToNativeFromVM ttn(thread);
 690   HandleMark hm(thread);
 691   return ZipLibrary::open(canonical_path, error_msg);
 692 }
 693 
 694 ClassPathEntry* ClassLoader::create_class_path_entry(JavaThread* current,
 695                                                      const char *path, const struct stat* st) {
 696   ClassPathEntry* new_entry = nullptr;
 697   if ((st->st_mode & S_IFMT) == S_IFREG) {
 698     ResourceMark rm(current);
 699     // Regular file, should be a zip file
 700     // Canonicalized filename
 701     const char* canonical_path = get_canonical_path(path, current);
 702     if (canonical_path == nullptr) {
 703       return nullptr;
 704     }
 705     char* error_msg = nullptr;
 706     jzfile* zip = open_zip_file(canonical_path, &error_msg, current);
 707     if (zip != nullptr && error_msg == nullptr) {
 708       new_entry = new ClassPathZipEntry(zip, path);
 709     } else {
 710       return nullptr;
 711     }
 712     log_info(class, path)("opened: %s", path);
 713     log_info(class, load)("opened: %s", path);
 714   } else {
 715     // Directory
 716     new_entry = new ClassPathDirEntry(path);
 717     log_info(class, load)("path: %s", path);
 718   }
 719   return new_entry;
 720 }
 721 
 722 
 723 // Create a class path zip entry for a given path (return null if not found
 724 // or zip/JAR file cannot be opened)
 725 ClassPathZipEntry* ClassLoader::create_class_path_zip_entry(const char *path) {
 726   // check for a regular file
 727   struct stat st;
 728   if (os::stat(path, &st) == 0) {
 729     if ((st.st_mode & S_IFMT) == S_IFREG) {
 730       JavaThread* thread = JavaThread::current();
 731       ResourceMark rm(thread);
 732       const char* canonical_path = get_canonical_path(path, thread);
 733       if (canonical_path != nullptr) {
 734         char* error_msg = nullptr;
 735         jzfile* zip = open_zip_file(canonical_path, &error_msg, thread);
 736         if (zip != nullptr && error_msg == nullptr) {
 737           // create using canonical path
 738           return new ClassPathZipEntry(zip, canonical_path);
 739         }
 740       }
 741     }
 742   }
 743   return nullptr;
 744 }
 745 
 746 // The boot append entries are added with a lock, and read lock free.
 747 void ClassLoader::add_to_boot_append_entries(ClassPathEntry *new_entry) {
 748   if (new_entry != nullptr) {
 749     MutexLocker ml(Bootclasspath_lock, Mutex::_no_safepoint_check_flag);
 750     if (_last_append_entry == nullptr) {
 751       _last_append_entry = new_entry;
 752       assert(first_append_entry() == nullptr, "boot loader's append class path entry list not empty");
 753       AtomicAccess::release_store(&_first_append_entry_list, new_entry);
 754     } else {
 755       _last_append_entry->set_next(new_entry);
 756       _last_append_entry = new_entry;
 757     }
 758   }
 759 }
 760 
 761 // Returns true IFF the file/dir exists and the entry was successfully created.
 762 bool ClassLoader::update_class_path_entry_list(JavaThread* current, const char *path) {
 763   struct stat st;
 764   if (os::stat(path, &st) == 0) {
 765     // File or directory found
 766     ClassPathEntry* new_entry = nullptr;
 767     new_entry = create_class_path_entry(current, path, &st);
 768     if (new_entry == nullptr) {
 769       return false;
 770     }
 771 
 772     // Do not reorder the bootclasspath which would break get_system_package().
 773     // Add new entry to linked list
 774     add_to_boot_append_entries(new_entry);
 775     return true;
 776   } else {
 777     return false;
 778   }
 779 }
 780 
 781 static void print_module_entry_table(const GrowableArray<ModuleClassPathList*>* const module_list) {
 782   ResourceMark rm;
 783   int num_of_entries = module_list->length();
 784   for (int i = 0; i < num_of_entries; i++) {
 785     ClassPathEntry* e;
 786     ModuleClassPathList* mpl = module_list->at(i);
 787     tty->print("%s=", mpl->module_name()->as_C_string());
 788     e = mpl->module_first_entry();
 789     while (e != nullptr) {
 790       tty->print("%s", e->name());
 791       e = e->next();
 792       if (e != nullptr) {
 793         tty->print("%s", os::path_separator());
 794       }
 795     }
 796     tty->print(" ;");
 797   }
 798 }
 799 
 800 void ClassLoader::print_bootclasspath() {
 801   ClassPathEntry* e;
 802   tty->print("[bootclasspath= ");
 803 
 804   // Print --patch-module module/path specifications first
 805   if (_patch_mod_entries != nullptr) {
 806     print_module_entry_table(_patch_mod_entries);
 807   }
 808 
 809   // [jimage | exploded modules build]
 810   if (has_jrt_entry()) {
 811     // Print the location of the java runtime image
 812     tty->print("%s ;", _jrt_entry->name());
 813   } else {
 814     // Print exploded module build path specifications
 815     if (_exploded_entries != nullptr) {
 816       print_module_entry_table(_exploded_entries);
 817     }
 818   }
 819 
 820   // appended entries
 821   e = first_append_entry();
 822   while (e != nullptr) {
 823     tty->print("%s ;", e->name());
 824     e = e->next();
 825   }
 826   tty->print_cr("]");
 827 }
 828 
 829 void* ClassLoader::dll_lookup(void* lib, const char* name, const char* path) {
 830   void* func = os::dll_lookup(lib, name);
 831   if (func == nullptr) {
 832     char msg[256] = "";
 833     jio_snprintf(msg, sizeof(msg), "Could not resolve \"%s\"", name);
 834     vm_exit_during_initialization(msg, path);
 835   }
 836   return func;
 837 }
 838 
 839 void ClassLoader::load_java_library() {
 840   assert(CanonicalizeEntry == nullptr, "should not load java library twice");
 841   if (is_vm_statically_linked()) {
 842     CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, os::lookup_function("JDK_Canonicalize"));
 843     assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize");
 844     return;
 845   }
 846 
 847   void *javalib_handle = os::native_java_library();
 848   if (javalib_handle == nullptr) {
 849     vm_exit_during_initialization("Unable to load java library", nullptr);
 850   }
 851 
 852   CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, dll_lookup(javalib_handle, "JDK_Canonicalize", nullptr));
 853   assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize in java library");
 854 }
 855 
 856 void ClassLoader::load_jimage_library() {
 857   assert(JImageOpen == nullptr, "should not load jimage library twice");
 858 
 859   if (is_vm_statically_linked()) {
 860       JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, os::lookup_function("JIMAGE_Open"));
 861       JImageClose = CAST_TO_FN_PTR(JImageClose_t, os::lookup_function("JIMAGE_Close"));
 862       JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, os::lookup_function("JIMAGE_FindResource"));
 863       JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, os::lookup_function("JIMAGE_GetResource"));
 864       assert(JImageOpen != nullptr && JImageClose != nullptr &&
 865             JImageFindResource != nullptr && JImageGetResource != nullptr,
 866             "could not lookup all jimage library functions");
 867       return;
 868     }
 869 
 870   char path[JVM_MAXPATHLEN];
 871   char ebuf[1024];
 872   void* handle = nullptr;
 873   if (os::dll_locate_lib(path, sizeof(path), Arguments::get_dll_dir(), "jimage")) {
 874     handle = os::dll_load(path, ebuf, sizeof ebuf);
 875   }
 876   if (handle == nullptr) {
 877     vm_exit_during_initialization("Unable to load jimage library", path);
 878   }
 879 
 880   JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, dll_lookup(handle, "JIMAGE_Open", path));
 881   JImageClose = CAST_TO_FN_PTR(JImageClose_t, dll_lookup(handle, "JIMAGE_Close", path));
 882   JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, dll_lookup(handle, "JIMAGE_FindResource", path));
 883   JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, dll_lookup(handle, "JIMAGE_GetResource", path));
 884   assert(JImageOpen != nullptr && JImageClose != nullptr &&
 885         JImageFindResource != nullptr && JImageGetResource != nullptr,
 886         "could not lookup all jimage library functions in jimage library");
 887 }
 888 
 889 int ClassLoader::crc32(int crc, const char* buf, int len) {
 890   return ZipLibrary::crc32(crc, (const jbyte*)buf, len);
 891 }
 892 
 893 oop ClassLoader::get_system_package(const char* name, TRAPS) {
 894   // Look up the name in the boot loader's package entry table.
 895   if (name != nullptr) {
 896     TempNewSymbol package_sym = SymbolTable::new_symbol(name);
 897     // Look for the package entry in the boot loader's package entry table.
 898     PackageEntry* package =
 899       ClassLoaderData::the_null_class_loader_data()->packages()->lookup_only(package_sym);
 900 
 901     // Return null if package does not exist or if no classes in that package
 902     // have been loaded.
 903     if (package != nullptr && package->has_loaded_class()) {
 904       ModuleEntry* module = package->module();
 905       if (module->location() != nullptr) {
 906         ResourceMark rm(THREAD);
 907         Handle ml = java_lang_String::create_from_str(
 908           module->location()->as_C_string(), THREAD);
 909         return ml();
 910       }
 911       // Return entry on boot loader class path.
 912       Handle cph = java_lang_String::create_from_str(
 913         ClassLoader::classpath_entry(package->classpath_index())->name(), THREAD);
 914       return cph();
 915     }
 916   }
 917   return nullptr;
 918 }
 919 
 920 objArrayOop ClassLoader::get_system_packages(TRAPS) {
 921   ResourceMark rm(THREAD);
 922   // List of pointers to PackageEntrys that have loaded classes.
 923   PackageEntryTable* pe_table =
 924       ClassLoaderData::the_null_class_loader_data()->packages();
 925   GrowableArray<PackageEntry*>* loaded_class_pkgs = pe_table->get_system_packages();
 926 
 927   // Allocate objArray and fill with java.lang.String
 928   objArrayOop r = oopFactory::new_objArray(vmClasses::String_klass(),
 929                                            loaded_class_pkgs->length(), CHECK_NULL);
 930   objArrayHandle result(THREAD, r);
 931   for (int x = 0; x < loaded_class_pkgs->length(); x++) {
 932     PackageEntry* package_entry = loaded_class_pkgs->at(x);
 933     Handle str = java_lang_String::create_from_symbol(package_entry->name(), CHECK_NULL);
 934     result->obj_at_put(x, str());
 935   }
 936   return result();
 937 }
 938 
 939 // caller needs ResourceMark
 940 const char* ClassLoader::file_name_for_class_name(const char* class_name,
 941                                                   int class_name_len) {
 942   assert(class_name != nullptr, "invariant");
 943   assert((int)strlen(class_name) == class_name_len, "invariant");
 944 
 945   static const char class_suffix[] = ".class";
 946   size_t class_suffix_len = sizeof(class_suffix);
 947 
 948   char* const file_name = NEW_RESOURCE_ARRAY(char,
 949                                              class_name_len +
 950                                              class_suffix_len); // includes term null
 951 
 952   strncpy(file_name, class_name, class_name_len);
 953   strncpy(&file_name[class_name_len], class_suffix, class_suffix_len);
 954 
 955   return file_name;
 956 }
 957 
 958 static ClassPathEntry* find_first_module_cpe(ModuleEntry* mod_entry,
 959                                              const GrowableArray<ModuleClassPathList*>* const module_list) {
 960   int num_of_entries = module_list->length();
 961   const Symbol* class_module_name = mod_entry->name();
 962 
 963   // Loop through all the modules in either the patch-module or exploded entries looking for module
 964   for (int i = 0; i < num_of_entries; i++) {
 965     ModuleClassPathList* module_cpl = module_list->at(i);
 966     Symbol* module_cpl_name = module_cpl->module_name();
 967 
 968     if (module_cpl_name->fast_compare(class_module_name) == 0) {
 969       // Class' module has been located.
 970       return module_cpl->module_first_entry();
 971     }
 972   }
 973   return nullptr;
 974 }
 975 
 976 
 977 // Search the module list for the class file stream based on the file name and java package
 978 ClassFileStream* ClassLoader::search_module_entries(JavaThread* current,
 979                                                     const GrowableArray<ModuleClassPathList*>* const module_list,
 980                                                     PackageEntry* pkg_entry, // Java package entry derived from the class name
 981                                                     const char* const file_name) {
 982   ClassFileStream* stream = nullptr;
 983 
 984   // Find the defining module in the boot loader's module entry table
 985   ModuleEntry* mod_entry = (pkg_entry != nullptr) ? pkg_entry->module() : nullptr;
 986 
 987   // If the module system has not defined java.base yet, then
 988   // classes loaded are assumed to be defined to java.base.
 989   // When java.base is eventually defined by the module system,
 990   // all packages of classes that have been previously loaded
 991   // are verified in ModuleEntryTable::verify_javabase_packages().
 992   if (!Universe::is_module_initialized() &&
 993       !ModuleEntryTable::javabase_defined() &&
 994       mod_entry == nullptr) {
 995     mod_entry = ModuleEntryTable::javabase_moduleEntry();
 996   }
 997 
 998   // The module must be a named module
 999   ClassPathEntry* e = nullptr;
1000   if (mod_entry != nullptr && mod_entry->is_named()) {
1001     if (module_list == _exploded_entries) {
1002       // The exploded build entries can be added to at any time so a lock is
1003       // needed when searching them.
1004       assert(!ClassLoader::has_jrt_entry(), "Must be exploded build");
1005       MutexLocker ml(current, Module_lock);
1006       e = find_first_module_cpe(mod_entry, module_list);
1007     } else {
1008       e = find_first_module_cpe(mod_entry, module_list);
1009     }
1010   }
1011 
1012   // Try to load the class from the module's ClassPathEntry list.
1013   while (e != nullptr) {
1014     stream = e->open_stream(current, file_name);
1015     // No context.check is required since CDS is not supported
1016     // for an exploded modules build or if --patch-module is specified.
1017     if (nullptr != stream) {
1018       return stream;
1019     }
1020     e = e->next();
1021   }
1022   // If the module was located, break out even if the class was not
1023   // located successfully from that module's ClassPathEntry list.
1024   // There will not be another valid entry for that module.
1025   return nullptr;
1026 }
1027 
1028 // Called by the boot classloader to load classes
1029 InstanceKlass* ClassLoader::load_class(Symbol* name, PackageEntry* pkg_entry, bool search_append_only, TRAPS) {
1030   assert(name != nullptr, "invariant");
1031 
1032   ResourceMark rm(THREAD);
1033   HandleMark hm(THREAD);
1034 
1035   const char* const class_name = name->as_C_string();
1036 
1037   EventMarkClassLoading m("Loading class %s", class_name);
1038 
1039   const char* const file_name = file_name_for_class_name(class_name,
1040                                                          name->utf8_length());
1041   assert(file_name != nullptr, "invariant");
1042 
1043   // Lookup stream for parsing .class file
1044   ClassFileStream* stream = nullptr;
1045   s2 classpath_index = 0;
1046   ClassPathEntry* e = nullptr;
1047 
1048   // If search_append_only is true, boot loader visibility boundaries are
1049   // set to be _first_append_entry to the end. This includes:
1050   //   [-Xbootclasspath/a]; [jvmti appended entries]
1051   //
1052   // If search_append_only is false, boot loader visibility boundaries are
1053   // set to be the --patch-module entries plus the base piece. This includes:
1054   //   [--patch-module=<module>=<file>(<pathsep><file>)*]; [jimage | exploded module build]
1055   //
1056 
1057   // Load Attempt #1: --patch-module
1058   // Determine the class' defining module.  If it appears in the _patch_mod_entries,
1059   // attempt to load the class from those locations specific to the module.
1060   // Specifications to --patch-module can contain a partial number of classes
1061   // that are part of the overall module definition.  So if a particular class is not
1062   // found within its module specification, the search should continue to Load Attempt #2.
1063   // Note: The --patch-module entries are never searched if the boot loader's
1064   //       visibility boundary is limited to only searching the append entries.
1065   if (_patch_mod_entries != nullptr && !search_append_only) {
1066     assert(!CDSConfig::is_dumping_archive(), "CDS doesn't support --patch-module during dumping");
1067     stream = search_module_entries(THREAD, _patch_mod_entries, pkg_entry, file_name);
1068   }
1069 
1070   // Load Attempt #2: [jimage | exploded build]
1071   if (!search_append_only && (nullptr == stream)) {
1072     if (has_jrt_entry()) {
1073       e = _jrt_entry;
1074       stream = _jrt_entry->open_stream(THREAD, file_name);
1075     } else {
1076       // Exploded build - attempt to locate class in its defining module's location.
1077       assert(_exploded_entries != nullptr, "No exploded build entries present");
1078       assert(!CDSConfig::is_dumping_archive(), "CDS dumping doesn't support exploded build");
1079       stream = search_module_entries(THREAD, _exploded_entries, pkg_entry, file_name);
1080     }
1081   }
1082 
1083   // Load Attempt #3: [-Xbootclasspath/a]; [jvmti appended entries]
1084   if (search_append_only && (nullptr == stream)) {
1085     // For the boot loader append path search, the starting classpath_index
1086     // for the appended piece is always 1 to account for either the
1087     // _jrt_entry or the _exploded_entries.
1088     assert(classpath_index == 0, "The classpath_index has been incremented incorrectly");
1089     classpath_index = 1;
1090 
1091     e = first_append_entry();
1092     while (e != nullptr) {
1093       stream = e->open_stream(THREAD, file_name);
1094       if (nullptr != stream) {
1095         break;
1096       }
1097       e = e->next();
1098       ++classpath_index;
1099     }
1100   }
1101 
1102   if (nullptr == stream) {
1103     return nullptr;
1104   }
1105 
1106   ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
1107   Handle protection_domain;
1108   ClassLoadInfo cl_info(protection_domain);
1109 
1110   InstanceKlass* result = KlassFactory::create_from_stream(stream,
1111                                                            name,
1112                                                            loader_data,
1113                                                            cl_info,
1114                                                            CHECK_NULL);
1115   result->set_classpath_index(classpath_index);
1116   return result;
1117 }
1118 
1119 #if INCLUDE_CDS
1120 static const char* skip_uri_protocol(const char* source) {
1121   if (strncmp(source, "file:", 5) == 0) {
1122     // file: protocol path could start with file:/ or file:///
1123     // locate the char after all the forward slashes
1124     int offset = 5;
1125     while (*(source + offset) == '/') {
1126         offset++;
1127     }
1128     source += offset;
1129   // for non-windows platforms, move back one char as the path begins with a '/'
1130 #ifndef _WINDOWS
1131     source -= 1;
1132 #endif
1133   } else if (strncmp(source, "jrt:/", 5) == 0) {
1134     source += 5;
1135   }
1136   return source;
1137 }
1138 
1139 static char decode_percent_encoded(const char *str, size_t& index) {
1140   if (str[index] == '%'
1141       && isxdigit(str[index + 1])
1142       && isxdigit(str[index + 2])) {
1143     char hex[3];
1144     hex[0] = str[index + 1];
1145     hex[1] = str[index + 2];
1146     hex[2] = '\0';
1147     index += 2;
1148     return (char) strtol(hex, nullptr, 16);
1149   }
1150   return str[index];
1151 }
1152 
1153 char* ClassLoader::uri_to_path(const char* uri) {
1154   const size_t len = strlen(uri) + 1;
1155   char* path = NEW_RESOURCE_ARRAY(char, len);
1156 
1157   uri = skip_uri_protocol(uri);
1158 
1159   if (strncmp(uri, "//", 2) == 0) {
1160     // Skip the empty "authority" part
1161     uri += 2;
1162   }
1163 
1164 #ifdef _WINDOWS
1165   if (uri[0] == '/') {
1166     // Absolute path name on Windows does not begin with a slash
1167     uri += 1;
1168   }
1169 #endif
1170 
1171   size_t path_index = 0;
1172   for (size_t i = 0; i < strlen(uri); ++i) {
1173     char decoded = decode_percent_encoded(uri, i);
1174     path[path_index++] = decoded;
1175   }
1176   path[path_index] = '\0';
1177   return path;
1178 }
1179 
1180 // Record the shared classpath index and loader type for classes loaded
1181 // by the builtin loaders at dump time.
1182 void ClassLoader::record_result(JavaThread* current, InstanceKlass* ik,
1183                                 const ClassFileStream* stream, bool redefined) {
1184   assert(CDSConfig::is_dumping_archive(), "sanity");
1185   assert(stream != nullptr, "sanity");
1186 
1187   if (ik->is_hidden()) {
1188     record_hidden_class(ik);
1189     return;
1190   }
1191 
1192   oop loader = ik->class_loader();
1193   char* src = (char*)stream->source();
1194   if (src == nullptr) {
1195     ik->set_shared_classpath_index(-1); // unsupported location
1196     return;
1197   }
1198 
1199   if (!SystemDictionaryShared::is_builtin_loader(ik->class_loader_data())) {
1200     // A class loaded by a user-defined classloader.
1201     assert(ik->shared_classpath_index() < 0, "not assigned yet");
1202     ik->set_shared_classpath_index(UNREGISTERED_INDEX);
1203     SystemDictionaryShared::set_shared_class_misc_info(ik, (ClassFileStream*)stream);
1204     return;
1205   }
1206 
1207   assert(has_jrt_entry(), "CDS dumping does not support exploded JDK build");
1208 
1209   ResourceMark rm(current);
1210   int classpath_index = -1;
1211   bool found_invalid = false;
1212 
1213   PackageEntry* pkg_entry = ik->package();
1214 
1215   if (!AOTClassLocationConfig::dumptime_is_ready()) {
1216     // The shared path table is set up after module system initialization.
1217     // The path table contains no entry before that. Any classes loaded prior
1218     // to the setup of the shared path table must be from the modules image.
1219     assert(stream->from_boot_loader_modules_image(), "stream must be loaded by boot loader from modules image");
1220     classpath_index = 0;
1221   } else {
1222     // Save the path from the file: protocol or the module name from the jrt: protocol
1223     // if no protocol prefix is found, path is the same as stream->source(). This path
1224     // must be valid since the class has been successfully parsed.
1225     const char* path = ClassLoader::uri_to_path(src);
1226     assert(path != nullptr, "sanity");
1227     AOTClassLocationConfig::dumptime_iterate([&] (AOTClassLocation* cl) {
1228       int i = cl->index();
1229       // for index 0 and the stream->source() is the modules image or has the jrt: protocol.
1230       // The class must be from the runtime modules image.
1231       if (cl->is_modules_image() && (stream->from_boot_loader_modules_image() || string_starts_with(src, "jrt:"))) {
1232         classpath_index = i;
1233       } else if (os::same_files(cl->path(), path)) {
1234         // If the path (from the class stream source) is the same as the shared
1235         // class or module path, then we have a match.
1236         // src may come from the App/Platform class loaders, which would canonicalize
1237         // the file name. We cannot use strcmp to check for equality against cs->path().
1238         // We must use os::same_files (which is faster than canonicalizing cs->path()).
1239 
1240         // null pkg_entry and pkg_entry in an unnamed module implies the class
1241         // is from the -cp or boot loader append path which consists of -Xbootclasspath/a
1242         // and jvmti appended entries.
1243         if ((pkg_entry == nullptr) || (pkg_entry->in_unnamed_module())) {
1244           // Ensure the index is within the -cp range before assigning
1245           // to the classpath_index.
1246           if (SystemDictionary::is_system_class_loader(loader) && cl->from_app_classpath()) {
1247             classpath_index = i;
1248           } else {
1249             if (cl->from_boot_classpath()) {
1250               if (loader != nullptr) {
1251                 // Probably loaded by jdk/internal/loader/ClassLoaders$BootClassLoader. Don't archive
1252                 // such classes.
1253                 found_invalid = true;
1254               } else {
1255                 classpath_index = i;
1256               }
1257             }
1258           }
1259         } else {
1260           // A class from a named module from the --module-path. Ensure the index is
1261           // within the --module-path range before assigning to the classpath_index.
1262           if ((pkg_entry != nullptr) && !(pkg_entry->in_unnamed_module()) && cl->from_module_path()) {
1263             classpath_index = i;
1264           }
1265         }
1266       }
1267       if (classpath_index >= 0 || found_invalid) {
1268         return false; // Break the AOTClassLocationConfig::dumptime_iterate() loop.
1269       } else {
1270         return true; // Keep iterating
1271       }
1272     });
1273   }
1274 
1275   if (found_invalid) {
1276     assert(classpath_index == -1, "sanity");
1277   }
1278 
1279   const char* const class_name = ik->name()->as_C_string();
1280   const char* const file_name = file_name_for_class_name(class_name,
1281                                                          ik->name()->utf8_length());
1282   assert(file_name != nullptr, "invariant");
1283   record_result_for_builtin_loader(checked_cast<s2>(classpath_index), ik, redefined);
1284 }
1285 
1286 void ClassLoader::record_result_for_builtin_loader(s2 classpath_index, InstanceKlass* result, bool redefined) {
1287   assert(CDSConfig::is_dumping_archive(), "sanity");
1288 
1289   oop loader = result->class_loader();
1290   if (SystemDictionary::is_system_class_loader(loader)) {
1291     AOTClassLocationConfig::dumptime_set_has_app_classes();
1292   } else if (SystemDictionary::is_platform_class_loader(loader)) {
1293     AOTClassLocationConfig::dumptime_set_has_platform_classes();
1294   } else {
1295     precond(loader == nullptr);
1296   }
1297 
1298   if (CDSConfig::is_dumping_preimage_static_archive() || CDSConfig::is_dumping_dynamic_archive()) {
1299     if (!AOTClassLocationConfig::dumptime()->is_valid_classpath_index(classpath_index, result)) {
1300       classpath_index = -1;
1301     }
1302   }
1303 
1304   AOTClassLocationConfig::dumptime_update_max_used_index(classpath_index);
1305   result->set_shared_classpath_index(classpath_index);
1306 }
1307 
1308 void ClassLoader::record_hidden_class(InstanceKlass* ik) {
1309   assert(ik->is_hidden(), "must be");
1310 
1311   if (ik->defined_by_other_loaders()) {
1312     // We don't archive hidden classes for non-builtin loaders.
1313     return;
1314   }
1315 
1316   if (HeapShared::is_lambda_proxy_klass(ik)) {
1317     InstanceKlass* nest_host = ik->nest_host_not_null();
1318     ik->set_shared_classpath_index(nest_host->shared_classpath_index());
1319   } else if (HeapShared::is_lambda_form_klass(ik)) {
1320     ik->set_shared_classpath_index(0);
1321   } else {
1322     // Generated invoker classes.
1323     if (ik->defined_by_app_loader()) {
1324       ik->set_shared_classpath_index(AOTClassLocationConfig::dumptime()->app_cp_start_index());
1325     } else {
1326       ik->set_shared_classpath_index(0);
1327     }
1328   }
1329 }
1330 
1331 void ClassLoader::append_boot_classpath(ClassPathEntry* new_entry) {
1332   if (CDSConfig::is_using_archive()) {
1333     warning("Sharing is only supported for boot loader classes because bootstrap classpath has been appended");
1334     FileMapInfo::current_info()->set_has_platform_or_app_classes(false);
1335     if (DynamicArchive::is_mapped()) {
1336       FileMapInfo::dynamic_info()->set_has_platform_or_app_classes(false);
1337     }
1338   }
1339   add_to_boot_append_entries(new_entry);
1340 }
1341 #endif // INCLUDE_CDS
1342 
1343 // Initialize the class loader's access to methods in libzip.  Parse and
1344 // process the boot classpath into a list ClassPathEntry objects.  Once
1345 // this list has been created, it must not change order (see class PackageInfo)
1346 // it can be appended to and is by jvmti.
1347 
1348 void ClassLoader::initialize(TRAPS) {
1349   if (UsePerfData) {
1350     // jvmstat performance counters
1351     NEWPERFTICKCOUNTER(_perf_accumulated_time, SUN_CLS, "time");
1352     NEWPERFTICKCOUNTER(_perf_class_init_time, SUN_CLS, "classInitTime");
1353     NEWPERFTICKCOUNTER(_perf_class_init_selftime, SUN_CLS, "classInitTime.self");
1354     NEWPERFTICKCOUNTER(_perf_class_verify_time, SUN_CLS, "classVerifyTime");
1355     NEWPERFTICKCOUNTER(_perf_class_verify_selftime, SUN_CLS, "classVerifyTime.self");
1356     NEWPERFTICKCOUNTER(_perf_class_link_time, SUN_CLS, "classLinkedTime");
1357     NEWPERFTICKCOUNTER(_perf_class_link_selftime, SUN_CLS, "classLinkedTime.self");
1358     NEWPERFEVENTCOUNTER(_perf_classes_inited, SUN_CLS, "initializedClasses");
1359     NEWPERFEVENTCOUNTER(_perf_classes_linked, SUN_CLS, "linkedClasses");
1360     NEWPERFEVENTCOUNTER(_perf_classes_verified, SUN_CLS, "verifiedClasses");
1361 
1362     NEWPERFTICKCOUNTER(_perf_shared_classload_time, SUN_CLS, "sharedClassLoadTime");
1363     NEWPERFTICKCOUNTER(_perf_sys_classload_time, SUN_CLS, "sysClassLoadTime");
1364     NEWPERFTICKCOUNTER(_perf_app_classload_time, SUN_CLS, "appClassLoadTime");
1365     NEWPERFTICKCOUNTER(_perf_app_classload_selftime, SUN_CLS, "appClassLoadTime.self");
1366     NEWPERFEVENTCOUNTER(_perf_app_classload_count, SUN_CLS, "appClassLoadCount");
1367     NEWPERFTICKCOUNTER(_perf_define_appclasses, SUN_CLS, "defineAppClasses");
1368     NEWPERFTICKCOUNTER(_perf_define_appclass_time, SUN_CLS, "defineAppClassTime");
1369     NEWPERFTICKCOUNTER(_perf_define_appclass_selftime, SUN_CLS, "defineAppClassTime.self");
1370     NEWPERFBYTECOUNTER(_perf_app_classfile_bytes_read, SUN_CLS, "appClassBytes");
1371     NEWPERFBYTECOUNTER(_perf_sys_classfile_bytes_read, SUN_CLS, "sysClassBytes");
1372     NEWPERFEVENTCOUNTER(_unsafe_defineClassCallCounter, SUN_CLS, "unsafeDefineClassCalls");
1373     NEWPERFTICKCOUNTER(_perf_secondary_hash_time, SUN_CLS, "secondarySuperHashTime");
1374     NEWPERFTICKCOUNTER(_perf_change_wx_time, SUN_CLS, "changeWXTime");
1375 
1376     if (log_is_enabled(Info, perf, class, link)) {
1377       NEWPERFTICKCOUNTER(_perf_ik_link_methods_time, SUN_CLS, "linkMethodsTime");
1378       NEWPERFTICKCOUNTER(_perf_method_adapters_time, SUN_CLS, "makeAdaptersTime");
1379       NEWPERFEVENTCOUNTER(_perf_ik_link_methods_count, SUN_CLS, "linkMethodsCount");
1380       NEWPERFEVENTCOUNTER(_perf_method_adapters_count, SUN_CLS, "makeAdaptersCount");
1381 
1382       NEWPERFTICKCOUNTER(_perf_resolve_indy_time, SUN_CLS, "resolve_invokedynamic_time");
1383       NEWPERFTICKCOUNTER(_perf_resolve_invokehandle_time, SUN_CLS, "resolve_invokehandle_time");
1384       NEWPERFTICKCOUNTER(_perf_resolve_mh_time, SUN_CLS, "resolve_MethodHandle_time");
1385       NEWPERFTICKCOUNTER(_perf_resolve_mt_time, SUN_CLS, "resolve_MethodType_time");
1386 
1387       NEWPERFEVENTCOUNTER(_perf_resolve_indy_count, SUN_CLS, "resolve_invokedynamic_count");
1388       NEWPERFEVENTCOUNTER(_perf_resolve_invokehandle_count, SUN_CLS, "resolve_invokehandle_count");
1389       NEWPERFEVENTCOUNTER(_perf_resolve_mh_count, SUN_CLS, "resolve_MethodHandle_count");
1390       NEWPERFEVENTCOUNTER(_perf_resolve_mt_count, SUN_CLS, "resolve_MethodType_count");
1391     }
1392   }
1393 
1394   // lookup java library entry points
1395   load_java_library();
1396   // jimage library entry points are loaded below, in lookup_vm_options
1397   setup_bootstrap_search_path(THREAD);
1398 }
1399 
1400 static char* lookup_vm_resource(JImageFile *jimage, const char *jimage_version, const char *path) {
1401   jlong size;
1402   JImageLocationRef location = (*JImageFindResource)(jimage, "java.base", jimage_version, path, &size);
1403   if (location == 0)
1404     return nullptr;
1405   char *val = NEW_C_HEAP_ARRAY(char, size+1, mtClass);
1406   (*JImageGetResource)(jimage, location, val, size);
1407   val[size] = '\0';
1408   return val;
1409 }
1410 
1411 // Lookup VM options embedded in the modules jimage file
1412 char* ClassLoader::lookup_vm_options() {
1413   jint error;
1414   char modules_path[JVM_MAXPATHLEN];
1415   const char* fileSep = os::file_separator();
1416 
1417   // Initialize jimage library entry points
1418   load_jimage_library();
1419 
1420   jio_snprintf(modules_path, JVM_MAXPATHLEN, "%s%slib%smodules", Arguments::get_java_home(), fileSep, fileSep);
1421   JImage_file =(*JImageOpen)(modules_path, &error);
1422   if (JImage_file == nullptr) {
1423     if (Arguments::has_jimage()) {
1424       // The modules file exists but is unreadable or corrupt
1425       vm_exit_during_initialization(err_msg("Unable to load %s", modules_path));
1426     }
1427     return nullptr;
1428   }
1429 
1430   const char *jimage_version = get_jimage_version_string();
1431   char *options = lookup_vm_resource(JImage_file, jimage_version, "jdk/internal/vm/options");
1432   return options;
1433 }
1434 
1435 bool ClassLoader::is_module_observable(const char* module_name) {
1436   assert(JImageOpen != nullptr, "jimage library should have been opened");
1437   if (JImage_file == nullptr) {
1438     struct stat st;
1439     const char *path = get_exploded_module_path(module_name, true);
1440     bool res = os::stat(path, &st) == 0;
1441     FREE_C_HEAP_ARRAY(char, path);
1442     return res;
1443   }
1444   jlong size;
1445   const char *jimage_version = get_jimage_version_string();
1446   return (*JImageFindResource)(JImage_file, module_name, jimage_version, "module-info.class", &size) != 0;
1447 }
1448 
1449 jlong ClassLoader::classloader_time_ms() {
1450   return UsePerfData ?
1451     Management::ticks_to_ms(_perf_accumulated_time->get_value()) : -1;
1452 }
1453 
1454 jlong ClassLoader::class_init_count() {
1455   return UsePerfData ? _perf_classes_inited->get_value() : -1;
1456 }
1457 
1458 jlong ClassLoader::class_init_time_ms() {
1459   return UsePerfData ?
1460     Management::ticks_to_ms(_perf_class_init_time->get_value()) : -1;
1461 }
1462 
1463 jlong ClassLoader::class_verify_time_ms() {
1464   return UsePerfData ?
1465     Management::ticks_to_ms(_perf_class_verify_time->get_value()) : -1;
1466 }
1467 
1468 jlong ClassLoader::class_link_count() {
1469   return UsePerfData ? _perf_classes_linked->get_value() : -1;
1470 }
1471 
1472 jlong ClassLoader::class_link_time_ms() {
1473   return UsePerfData ?
1474     Management::ticks_to_ms(_perf_class_link_time->get_value()) : -1;
1475 }
1476 
1477 int ClassLoader::compute_Object_vtable() {
1478   // hardwired for JDK1.2 -- would need to duplicate class file parsing
1479   // code to determine actual value from file
1480   // Would be value '11' if finals were in vtable
1481   int JDK_1_2_Object_vtable_size = 5;
1482   return JDK_1_2_Object_vtable_size * vtableEntry::size();
1483 }
1484 
1485 
1486 void classLoader_init1() {
1487   EXCEPTION_MARK;
1488   ClassLoader::initialize(THREAD);
1489   if (HAS_PENDING_EXCEPTION) {
1490     vm_exit_during_initialization("ClassLoader::initialize() failed unexpectedly");
1491   }
1492 }
1493 
1494 // Complete the ClassPathEntry setup for the boot loader
1495 void ClassLoader::classLoader_init2(JavaThread* current) {
1496   // Setup the list of module/path pairs for --patch-module processing
1497   // This must be done after the SymbolTable is created in order
1498   // to use fast_compare on module names instead of a string compare.
1499   if (Arguments::get_patch_mod_prefix() != nullptr) {
1500     setup_patch_mod_entries();
1501   }
1502 
1503   // Create the ModuleEntry for java.base (must occur after setup_patch_mod_entries
1504   // to successfully determine if java.base has been patched)
1505   create_javabase();
1506 
1507   // Setup the initial java.base/path pair for the exploded build entries.
1508   // As more modules are defined during module system initialization, more
1509   // entries will be added to the exploded build array.
1510   if (!has_jrt_entry()) {
1511     assert(!CDSConfig::is_dumping_archive(), "not supported with exploded module builds");
1512     assert(!CDSConfig::is_using_archive(), "UsedSharedSpaces not supported with exploded module builds");
1513     // Set up the boot loader's _exploded_entries list.  Note that this gets
1514     // done before loading any classes, by the same thread that will
1515     // subsequently do the first class load. So, no lock is needed for this.
1516     assert(_exploded_entries == nullptr, "Should only get initialized once");
1517     _exploded_entries = new (mtModule)
1518       GrowableArray<ModuleClassPathList*>(EXPLODED_ENTRY_SIZE, mtModule);
1519     add_to_exploded_build_list(current, vmSymbols::java_base());
1520   }
1521 }
1522 
1523 char* ClassLoader::get_canonical_path(const char* orig, Thread* thread) {
1524   assert(orig != nullptr, "bad arguments");
1525   // caller needs to allocate ResourceMark for the following output buffer
1526   char* canonical_path = NEW_RESOURCE_ARRAY_IN_THREAD(thread, char, JVM_MAXPATHLEN);
1527   ResourceMark rm(thread);
1528   // os::native_path writes into orig_copy
1529   char* orig_copy = ResourceArea::strdup(thread, orig);
1530   if ((CanonicalizeEntry)(os::native_path(orig_copy), canonical_path, JVM_MAXPATHLEN) < 0) {
1531     return nullptr;
1532   }
1533   return canonical_path;
1534 }
1535 
1536 void ClassLoader::create_javabase() {
1537   JavaThread* current = JavaThread::current();
1538 
1539   // Create java.base's module entry for the boot
1540   // class loader prior to loading j.l.Object.
1541   ClassLoaderData* null_cld = ClassLoaderData::the_null_class_loader_data();
1542 
1543   // Get module entry table
1544   ModuleEntryTable* null_cld_modules = null_cld->modules();
1545   if (null_cld_modules == nullptr) {
1546     vm_exit_during_initialization("No ModuleEntryTable for the boot class loader");
1547   }
1548 
1549   {
1550     MutexLocker ml(current, Module_lock);
1551     if (ModuleEntryTable::javabase_moduleEntry() == nullptr) {  // may have been inited by CDS.
1552       ModuleEntry* jb_module = null_cld_modules->locked_create_entry(Handle(),
1553                                false, vmSymbols::java_base(), nullptr, nullptr, null_cld);
1554       if (jb_module == nullptr) {
1555         vm_exit_during_initialization("Unable to create ModuleEntry for " JAVA_BASE_NAME);
1556       }
1557       ModuleEntryTable::set_javabase_moduleEntry(jb_module);
1558     }
1559   }
1560 }
1561 
1562 // Please keep following two functions at end of this file. With them placed at top or in middle of the file,
1563 // they could get inlined by aggressive compiler, an unknown trick, see bug 6966589.
1564 void PerfClassTraceTime::initialize() {
1565   if (!UsePerfData) return;
1566 
1567   if (_eventp != nullptr) {
1568     // increment the event counter
1569     _eventp->inc();
1570   }
1571 
1572   // stop the current active thread-local timer to measure inclusive time
1573   _prev_active_event = -1;
1574   for (int i=0; i < EVENT_TYPE_COUNT; i++) {
1575      if (_timers[i].is_active()) {
1576        assert(_prev_active_event == -1, "should have only one active timer");
1577        _prev_active_event = i;
1578        _timers[i].stop();
1579      }
1580   }
1581 
1582   if (_recursion_counters == nullptr || (_recursion_counters[_event_type])++ == 0) {
1583     // start the inclusive timer if not recursively called
1584     _t.start();
1585   }
1586 
1587   // start thread-local timer of the given event type
1588    if (!_timers[_event_type].is_active()) {
1589     _timers[_event_type].start();
1590   }
1591 }
1592 
1593 PerfClassTraceTime::~PerfClassTraceTime() {
1594   if (!UsePerfData) return;
1595 
1596   // stop the thread-local timer as the event completes
1597   // and resume the thread-local timer of the event next on the stack
1598   _timers[_event_type].stop();
1599   jlong selftime = _timers[_event_type].ticks();
1600 
1601   if (_prev_active_event >= 0) {
1602     _timers[_prev_active_event].start();
1603   }
1604 
1605   if (_recursion_counters != nullptr && --(_recursion_counters[_event_type]) > 0) return;
1606 
1607   // increment the counters only on the leaf call
1608   _t.stop();
1609   _timep->inc(_t.ticks());
1610   if (_selftimep != nullptr) {
1611     _selftimep->inc(selftime);
1612   }
1613   // add all class loading related event selftime to the accumulated time counter
1614   ClassLoader::perf_accumulated_time()->inc(selftime);
1615 
1616   // reset the timer
1617   _timers[_event_type].reset();
1618 }