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 // PreviewMode status to control preview behaviour. JImage_file is unusable
 103 // for normal lookup until (Preview_mode != PREVIEW_MODE_UNINITIALIZED).
 104 enum PreviewMode {
 105   PREVIEW_MODE_UNINITIALIZED = 0,
 106   PREVIEW_MODE_DEFAULT = 1,
 107   PREVIEW_MODE_ENABLE_PREVIEW = 2
 108 };
 109 static PreviewMode                     Preview_mode           = PREVIEW_MODE_UNINITIALIZED;
 110 
 111 // Globals
 112 
 113 PerfCounter*    ClassLoader::_perf_accumulated_time = nullptr;
 114 PerfCounter*    ClassLoader::_perf_classes_inited = nullptr;
 115 PerfCounter*    ClassLoader::_perf_class_init_time = nullptr;
 116 PerfCounter*    ClassLoader::_perf_class_init_selftime = nullptr;
 117 PerfCounter*    ClassLoader::_perf_classes_verified = nullptr;
 118 PerfCounter*    ClassLoader::_perf_class_verify_time = nullptr;
 119 PerfCounter*    ClassLoader::_perf_class_verify_selftime = nullptr;
 120 PerfCounter*    ClassLoader::_perf_classes_linked = nullptr;
 121 PerfCounter*    ClassLoader::_perf_class_link_time = nullptr;
 122 PerfCounter*    ClassLoader::_perf_class_link_selftime = nullptr;
 123 PerfCounter*    ClassLoader::_perf_shared_classload_time = nullptr;
 124 PerfCounter*    ClassLoader::_perf_sys_classload_time = nullptr;
 125 PerfCounter*    ClassLoader::_perf_app_classload_time = nullptr;
 126 PerfCounter*    ClassLoader::_perf_app_classload_selftime = nullptr;
 127 PerfCounter*    ClassLoader::_perf_app_classload_count = nullptr;
 128 PerfCounter*    ClassLoader::_perf_define_appclasses = nullptr;
 129 PerfCounter*    ClassLoader::_perf_define_appclass_time = nullptr;
 130 PerfCounter*    ClassLoader::_perf_define_appclass_selftime = nullptr;
 131 PerfCounter*    ClassLoader::_perf_app_classfile_bytes_read = nullptr;
 132 PerfCounter*    ClassLoader::_perf_sys_classfile_bytes_read = nullptr;
 133 PerfCounter*    ClassLoader::_perf_ik_link_methods_time = nullptr;
 134 PerfCounter*    ClassLoader::_perf_method_adapters_time = nullptr;
 135 PerfCounter*    ClassLoader::_perf_ik_link_methods_count = nullptr;
 136 PerfCounter*    ClassLoader::_perf_method_adapters_count = nullptr;
 137 PerfCounter*    ClassLoader::_unsafe_defineClassCallCounter = nullptr;
 138 PerfCounter*    ClassLoader::_perf_secondary_hash_time = nullptr;
 139 PerfCounter*    ClassLoader::_perf_change_wx_time = nullptr;
 140 
 141 PerfCounter*    ClassLoader::_perf_resolve_indy_time = nullptr;
 142 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_time = nullptr;
 143 PerfCounter*    ClassLoader::_perf_resolve_mh_time = nullptr;
 144 PerfCounter*    ClassLoader::_perf_resolve_mt_time = nullptr;
 145 
 146 PerfCounter*    ClassLoader::_perf_resolve_indy_count = nullptr;
 147 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_count = nullptr;
 148 PerfCounter*    ClassLoader::_perf_resolve_mh_count = nullptr;
 149 PerfCounter*    ClassLoader::_perf_resolve_mt_count = nullptr;
 150 
 151 void ClassLoader::print_counters(outputStream *st) {
 152   st->print_cr("ClassLoader:");
 153   st->print_cr("  clinit:               " JLONG_FORMAT "ms / " JLONG_FORMAT " events", ClassLoader::class_init_time_ms(), ClassLoader::class_init_count());
 154   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());
 155   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());
 156   st->print_cr("  resolve...");
 157   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());
 158   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());
 159   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());
 160   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());
 161   st->cr();
 162 }
 163 
 164 GrowableArray<ModuleClassPathList*>* ClassLoader::_patch_mod_entries = nullptr;
 165 GrowableArray<ModuleClassPathList*>* ClassLoader::_exploded_entries = nullptr;
 166 ClassPathImageEntry* ClassLoader::_jrt_entry = nullptr;
 167 
 168 ClassPathEntry* volatile ClassLoader::_first_append_entry_list = nullptr;
 169 ClassPathEntry* volatile ClassLoader::_last_append_entry  = nullptr;
 170 
 171 // helper routines
 172 #if INCLUDE_CDS
 173 static bool string_starts_with(const char* str, const char* str_to_find) {
 174   size_t str_len = strlen(str);
 175   size_t str_to_find_len = strlen(str_to_find);
 176   if (str_to_find_len > str_len) {
 177     return false;
 178   }
 179   return (strncmp(str, str_to_find, str_to_find_len) == 0);
 180 }
 181 #endif
 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 // --------------------------------
 238 // The following jimage_xxx static functions encapsulate all JImage_file and Preview_mode access.
 239 // This is done to make it easy to reason about the JImage file state (exists vs initialized etc.).
 240 
 241 // Opens the named JImage file and sets the JImage file reference.
 242 // Returns true if opening the JImage file was successful (see also jimage_exists()).
 243 static bool jimage_open(const char* modules_path) {
 244   // Currently 'error' is not set to anything useful, so ignore it here.
 245   jint error;
 246   JImage_file = (*JImageOpen)(modules_path, &error);
 247   return JImage_file != nullptr;
 248 }
 249 
 250 // Closes and clears the JImage file reference (this will only be called during shutdown).
 251 static void jimage_close() {
 252   if (JImage_file != nullptr) {
 253     (*JImageClose)(JImage_file);
 254     JImage_file = nullptr;
 255   }
 256 }
 257 
 258 // Returns whether a JImage file was opened (but NOT whether it was initialized yet).
 259 static bool jimage_exists() {
 260   return JImage_file != nullptr;
 261 }
 262 
 263 // Returns the JImage file reference (which may or may not be initialized).
 264 static JImageFile* jimage_non_null() {
 265   assert(jimage_exists(), "should have been opened by ClassLoader::lookup_vm_options "
 266                           "and remained throughout normal JVM lifetime");
 267   return JImage_file;
 268 }
 269 
 270 // Returns true if jimage_init() has been called. Once the JImage file is initialized,
 271 // jimage_is_preview_enabled() can be called to correctly determine the access mode.
 272 static bool jimage_is_initialized() {
 273   return jimage_exists() && Preview_mode != PREVIEW_MODE_UNINITIALIZED;
 274 }
 275 
 276 // Returns the access mode for an initialized JImage file (reflects --enable-preview).
 277 static bool is_preview_enabled() {
 278   return Preview_mode == PREVIEW_MODE_ENABLE_PREVIEW;
 279 }
 280 
 281 // Looks up the location of a named JImage resource. This "raw" lookup function allows
 282 // the preview mode to be manually specified, so must not be accessible outside this
 283 // class. ClassPathImageEntry manages all calls for resources after startup is complete.
 284 static JImageLocationRef jimage_find_resource(const char* module_name,
 285                                               const char* file_name,
 286                                               bool is_preview,
 287                                               jlong *size) {
 288   return ((*JImageFindResource)(jimage_non_null(),
 289                                 module_name,
 290                                 file_name,
 291                                 is_preview,
 292                                 size));
 293 }
 294 // --------------------------------
 295 
 296 // Given a fully qualified package name, find its defining package in the class loader's
 297 // package entry table.
 298 PackageEntry* ClassLoader::get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data) {
 299   if (pkg_name == nullptr) {
 300     return nullptr;
 301   }
 302   PackageEntryTable* pkgEntryTable = loader_data->packages();
 303   return pkgEntryTable->lookup_only(pkg_name);
 304 }
 305 
 306 const char* ClassPathEntry::copy_path(const char* path) {
 307   char* copy = NEW_C_HEAP_ARRAY(char, strlen(path)+1, mtClass);
 308   strcpy(copy, path);
 309   return copy;
 310 }
 311 
 312 ClassPathDirEntry::~ClassPathDirEntry() {
 313   FREE_C_HEAP_ARRAY(char, _dir);
 314 }
 315 
 316 ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char* name) {
 317   // construct full path name
 318   assert((_dir != nullptr) && (name != nullptr), "sanity");
 319   size_t path_len = strlen(_dir) + strlen(name) + strlen(os::file_separator()) + 1;
 320   char* path = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, path_len);
 321   int len = jio_snprintf(path, path_len, "%s%s%s", _dir, os::file_separator(), name);
 322   assert(len == (int)(path_len - 1), "sanity");
 323   // check if file exists
 324   struct stat st;
 325   if (os::stat(path, &st) == 0) {
 326     // found file, open it
 327     int file_handle = os::open(path, 0, 0);
 328     if (file_handle != -1) {
 329       // read contents into resource array
 330       u1* buffer = NEW_RESOURCE_ARRAY_IN_THREAD(current, u1, st.st_size);
 331       size_t num_read = ::read(file_handle, (char*) buffer, st.st_size);
 332       // close file
 333       ::close(file_handle);
 334       // construct ClassFileStream
 335       if (num_read == (size_t)st.st_size) {
 336         if (UsePerfData) {
 337           ClassLoader::perf_sys_classfile_bytes_read()->inc(num_read);
 338         }
 339 #ifdef ASSERT
 340         // Freeing path is a no-op here as buffer prevents it from being reclaimed. But we keep it for
 341         // debug builds so that we guard against use-after-free bugs.
 342         FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 343 #endif
 344         // We don't verify the length of the classfile stream fits in an int, but this is the
 345         // bootloader so we have control of this.
 346         // Resource allocated
 347         return new ClassFileStream(buffer,
 348                                    checked_cast<int>(st.st_size),
 349                                    _dir);
 350       }
 351     }
 352   }
 353   FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 354   return nullptr;
 355 }
 356 
 357 ClassPathZipEntry::ClassPathZipEntry(jzfile* zip, const char* zip_name) : ClassPathEntry() {
 358   _zip = zip;
 359   _zip_name = copy_path(zip_name);
 360 }
 361 
 362 ClassPathZipEntry::~ClassPathZipEntry() {
 363   ZipLibrary::close(_zip);
 364   FREE_C_HEAP_ARRAY(char, _zip_name);
 365 }
 366 
 367 bool ClassPathZipEntry::has_entry(JavaThread* current, const char* name) {
 368   ThreadToNativeFromVM ttn(current);
 369   // check whether zip archive contains name
 370   jint name_len;
 371   jint filesize;
 372   jzentry* entry = ZipLibrary::find_entry(_zip, name, &filesize, &name_len);
 373   if (entry == nullptr) {
 374     return false;
 375   } else {
 376      ZipLibrary::free_entry(_zip, entry);
 377     return true;
 378   }
 379 }
 380 
 381 u1* ClassPathZipEntry::open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate) {
 382   // enable call to C land
 383   ThreadToNativeFromVM ttn(current);
 384   // check whether zip archive contains name
 385   jint name_len;
 386   jzentry* entry = ZipLibrary::find_entry(_zip, name, filesize, &name_len);
 387   if (entry == nullptr) return nullptr;
 388   u1* buffer;
 389   char name_buf[128];
 390   char* filename;
 391   if (name_len < 128) {
 392     filename = name_buf;
 393   } else {
 394     filename = NEW_RESOURCE_ARRAY(char, name_len + 1);
 395   }
 396 
 397   // read contents into resource array
 398   size_t size = (uint32_t)(*filesize);
 399   if (nul_terminate) {
 400     if (sizeof(size) == sizeof(uint32_t) && size == UINT_MAX) {
 401       return nullptr; // 32-bit integer overflow will occur.
 402     }
 403     size++;
 404   }
 405   buffer = NEW_RESOURCE_ARRAY(u1, size);
 406   if (!ZipLibrary::read_entry(_zip, entry, buffer, filename)) {
 407     return nullptr;
 408   }
 409 
 410   // return result
 411   if (nul_terminate) {
 412     buffer[size - 1] = 0;
 413   }
 414   return buffer;
 415 }
 416 
 417 ClassFileStream* ClassPathZipEntry::open_stream(JavaThread* current, const char* name) {
 418   jint filesize;
 419   u1* buffer = open_entry(current, name, &filesize, false);
 420   if (buffer == nullptr) {
 421     return nullptr;
 422   }
 423   if (UsePerfData) {
 424     ClassLoader::perf_sys_classfile_bytes_read()->inc(filesize);
 425   }
 426   // Resource allocated
 427   return new ClassFileStream(buffer,
 428                              filesize,
 429                              _zip_name);
 430 }
 431 
 432 DEBUG_ONLY(ClassPathImageEntry* ClassPathImageEntry::_singleton = nullptr;)
 433 











 434 void ClassPathImageEntry::close_jimage() {
 435   jimage_close();



 436 }
 437 
 438 ClassPathImageEntry::ClassPathImageEntry(const char* name) :
 439   ClassPathEntry() {
 440   guarantee(jimage_is_initialized(), "jimage is not initialized");
 441   guarantee(name != nullptr, "jimage file name is null");
 442 
 443   assert(_singleton == nullptr, "VM supports only one jimage");
 444   DEBUG_ONLY(_singleton = this);
 445   size_t len = strlen(name) + 1;
 446   _name = copy_path(name);
 447 }
 448 
 449 ClassFileStream* ClassPathImageEntry::open_stream(JavaThread* current, const char* name) {
 450   return open_stream_for_loader(current, name, ClassLoaderData::the_null_class_loader_data());
 451 }
 452 
 453 // For a class in a named module, look it up in the jimage file using this syntax:
 454 //    /<module-name>/<package-name>/<base-class>
 455 //
 456 // Assumptions:
 457 //     1. There are no unnamed modules in the jimage file.
 458 //     2. A package is in at most one module in the jimage file.
 459 //
 460 ClassFileStream* ClassPathImageEntry::open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) {
 461   const bool is_preview = is_preview_enabled();
 462 
 463   jlong size;
 464   JImageLocationRef location = 0;
 465 
 466   TempNewSymbol class_name = SymbolTable::new_symbol(name);
 467   TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
 468 
 469   if (pkg_name != nullptr) {
 470     if (!Universe::is_module_initialized()) {
 471       location = jimage_find_resource(JAVA_BASE_NAME, name, is_preview, &size);
 472     } else {
 473       PackageEntry* package_entry = ClassLoader::get_package_entry(pkg_name, loader_data);
 474       if (package_entry != nullptr) {
 475         ResourceMark rm(current);
 476         // Get the module name
 477         ModuleEntry* module = package_entry->module();
 478         assert(module != nullptr, "Boot classLoader package missing module");
 479         assert(module->is_named(), "Boot classLoader package is in unnamed module");
 480         const char* module_name = module->name()->as_C_string();
 481         if (module_name != nullptr) {
 482           location = jimage_find_resource(module_name, name, is_preview, &size);
 483         }
 484       }
 485     }
 486   }
 487 
 488   if (location != 0) {
 489     if (UsePerfData) {
 490       ClassLoader::perf_sys_classfile_bytes_read()->inc(size);
 491     }
 492     char* data = NEW_RESOURCE_ARRAY(char, size);
 493     (*JImageGetResource)(jimage_non_null(), location, data, size);
 494     // Resource allocated
 495     assert(this == ClassLoader::get_jrt_entry(), "must be");
 496     return new ClassFileStream((u1*)data,
 497                                checked_cast<int>(size),
 498                                _name,
 499                                true); // from_boot_loader_modules_image
 500   }
 501 
 502   return nullptr;
 503 }
 504 







 505 bool ClassPathImageEntry::is_modules_image() const {
 506   assert(this == _singleton, "VM supports a single jimage");
 507   assert(this == ClassLoader::get_jrt_entry(), "must be used for jrt entry");
 508   return true;
 509 }
 510 
 511 ModuleClassPathList::ModuleClassPathList(Symbol* module_name) {
 512   _module_name = module_name;
 513   _module_first_entry = nullptr;
 514   _module_last_entry = nullptr;
 515 }
 516 
 517 ModuleClassPathList::~ModuleClassPathList() {
 518   // Clean out each ClassPathEntry on list
 519   ClassPathEntry* e = _module_first_entry;
 520   while (e != nullptr) {
 521     ClassPathEntry* next_entry = e->next();
 522     delete e;
 523     e = next_entry;
 524   }
 525 }
 526 
 527 void ModuleClassPathList::add_to_list(ClassPathEntry* new_entry) {
 528   if (new_entry != nullptr) {
 529     if (_module_last_entry == nullptr) {
 530       _module_first_entry = _module_last_entry = new_entry;
 531     } else {
 532       _module_last_entry->set_next(new_entry);
 533       _module_last_entry = new_entry;
 534     }
 535   }
 536 }
 537 
 538 void ClassLoader::trace_class_path(const char* msg, const char* name) {
 539   LogTarget(Info, class, path) lt;
 540   if (lt.is_enabled()) {
 541     LogStream ls(lt);
 542     if (msg) {
 543       ls.print("%s", msg);
 544     }
 545     if (name) {
 546       if (strlen(name) < 256) {
 547         ls.print("%s", name);
 548       } else {
 549         // For very long paths, we need to print each character separately,
 550         // as print_cr() has a length limit
 551         while (name[0] != '\0') {
 552           ls.print("%c", name[0]);
 553           name++;
 554         }
 555       }
 556     }
 557     ls.cr();
 558   }
 559 }
 560 
 561 void ClassLoader::setup_bootstrap_search_path(JavaThread* current) {
 562   const char* bootcp = Arguments::get_boot_class_path();
 563   assert(bootcp != nullptr, "Boot class path must not be nullptr");
 564   if (PrintSharedArchiveAndExit) {
 565     // Don't print bootcp - this is the bootcp of this current VM process, not necessarily
 566     // the same as the boot classpath of the shared archive.
 567   } else {
 568     trace_class_path("bootstrap loader class path=", bootcp);
 569   }
 570   setup_bootstrap_search_path_impl(current, bootcp);
 571 }
 572 
 573 void ClassLoader::close_jrt_image() {
 574   // Not applicable for exploded builds
 575   if (!ClassLoader::has_jrt_entry()) return;
 576   _jrt_entry->close_jimage();
 577 }
 578 
 579 // Construct the array of module/path pairs as specified to --patch-module
 580 // for the boot loader to search ahead of the jimage, if the class being
 581 // loaded is defined to a module that has been specified to --patch-module.
 582 void ClassLoader::setup_patch_mod_entries() {
 583   JavaThread* current = JavaThread::current();
 584   GrowableArray<ModulePatchPath*>* patch_mod_args = Arguments::get_patch_mod_prefix();
 585   int num_of_entries = patch_mod_args->length();
 586 
 587   // Set up the boot loader's _patch_mod_entries list
 588   _patch_mod_entries = new (mtModule) GrowableArray<ModuleClassPathList*>(num_of_entries, mtModule);
 589 
 590   for (int i = 0; i < num_of_entries; i++) {
 591     const char* module_name = (patch_mod_args->at(i))->module_name();
 592     Symbol* const module_sym = SymbolTable::new_symbol(module_name);
 593     assert(module_sym != nullptr, "Failed to obtain Symbol for module name");
 594     ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 595 
 596     char* class_path = (patch_mod_args->at(i))->path_string();
 597     ResourceMark rm(current);
 598     ClasspathStream cp_stream(class_path);
 599 
 600     while (cp_stream.has_next()) {
 601       const char* path = cp_stream.get_next();
 602       struct stat st;
 603       if (os::stat(path, &st) == 0) {
 604         // File or directory found
 605         ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);
 606         // If the path specification is valid, enter it into this module's list
 607         if (new_entry != nullptr) {
 608           module_cpl->add_to_list(new_entry);
 609         }
 610       }
 611     }
 612 
 613     // Record the module into the list of --patch-module entries only if
 614     // valid ClassPathEntrys have been created
 615     if (module_cpl->module_first_entry() != nullptr) {
 616       _patch_mod_entries->push(module_cpl);
 617     }
 618   }
 619 }
 620 
 621 // Determine whether the module has been patched via the command-line
 622 // option --patch-module
 623 bool ClassLoader::is_in_patch_mod_entries(Symbol* module_name) {
 624   if (_patch_mod_entries != nullptr && _patch_mod_entries->is_nonempty()) {
 625     int table_len = _patch_mod_entries->length();
 626     for (int i = 0; i < table_len; i++) {
 627       ModuleClassPathList* patch_mod = _patch_mod_entries->at(i);
 628       if (module_name->fast_compare(patch_mod->module_name()) == 0) {
 629         return true;
 630       }
 631     }
 632   }
 633   return false;
 634 }
 635 
 636 // Set up the _jrt_entry if present and boot append path
 637 void ClassLoader::setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path) {
 638   ResourceMark rm(current);
 639   ClasspathStream cp_stream(class_path);
 640   bool set_base_piece = true;
 641 
 642 #if INCLUDE_CDS
 643   if (CDSConfig::is_dumping_archive()) {
 644     if (!Arguments::has_jimage()) {
 645       vm_exit_during_initialization("CDS is not supported in exploded JDK build", nullptr);
 646     }
 647   }
 648 #endif
 649 
 650   while (cp_stream.has_next()) {
 651     const char* path = cp_stream.get_next();
 652 
 653     if (set_base_piece) {
 654       // The first time through the bootstrap_search setup, it must be determined
 655       // what the base or core piece of the boot loader search is.  Either a java runtime
 656       // image is present or this is an exploded module build situation.
 657       assert(string_ends_with(path, MODULES_IMAGE_NAME) || string_ends_with(path, JAVA_BASE_NAME),
 658              "Incorrect boot loader search path, no java runtime image or " JAVA_BASE_NAME " exploded build");
 659       struct stat st;
 660       if (os::stat(path, &st) == 0) {
 661         // Directory found
 662         if (jimage_exists()) {
 663           assert(Arguments::has_jimage(), "sanity check");
 664           const char* canonical_path = get_canonical_path(path, current);
 665           assert(canonical_path != nullptr, "canonical_path issue");
 666 
 667           // Hand over lifecycle control of the JImage file to the _jrt_entry singleton
 668           // (see ClassPathImageEntry::close_jimage). The image must be initialized by now.
 669           _jrt_entry = new ClassPathImageEntry(canonical_path);
 670           assert(_jrt_entry != nullptr && _jrt_entry->is_modules_image(), "No java runtime image present");

 671         } // else it's an exploded build.
 672       } else {
 673         // If path does not exist, exit
 674         vm_exit_during_initialization("Unable to establish the boot loader search path", path);
 675       }
 676       set_base_piece = false;
 677     } else {
 678       // Every entry on the boot class path after the initial base piece,
 679       // which is set by os::set_boot_path(), is considered an appended entry.
 680       update_class_path_entry_list(current, path);
 681     }
 682   }
 683 }
 684 
 685 // Gets the exploded path for the named module. The memory for the path
 686 // is allocated on the C heap if `c_heap` is true otherwise in the resource area.
 687 static const char* get_exploded_module_path(const char* module_name, bool c_heap) {
 688   const char *home = Arguments::get_java_home();
 689   const char file_sep = os::file_separator()[0];
 690   // 10 represents the length of "modules" (7) + 2 file separators + \0
 691   size_t len = strlen(home) + strlen(module_name) + 10;
 692   char *path = c_heap ? NEW_C_HEAP_ARRAY(char, len, mtModule) : NEW_RESOURCE_ARRAY(char, len);
 693   jio_snprintf(path, len, "%s%cmodules%c%s", home, file_sep, file_sep, module_name);
 694   return path;
 695 }
 696 
 697 // Gets a preview path for a given class path as a resource.
 698 static const char* get_preview_path(const char* path) {
 699   const char file_sep = os::file_separator()[0];
 700   // 18 represents the length of "META-INF" (8) + "preview" (7) + 2 file separators + \0
 701   size_t len = strlen(path) + 18;
 702   char *preview_path = NEW_RESOURCE_ARRAY(char, len);
 703   jio_snprintf(preview_path, len, "%s%cMETA-INF%cpreview", path, file_sep, file_sep);
 704   return preview_path;
 705 }
 706 
 707 // During an exploded modules build, each module defined to the boot loader
 708 // will be added to the ClassLoader::_exploded_entries array.
 709 void ClassLoader::add_to_exploded_build_list(JavaThread* current, Symbol* module_sym) {
 710   assert(!ClassLoader::has_jrt_entry(), "Exploded build not applicable");
 711   assert(_exploded_entries != nullptr, "_exploded_entries was not initialized");
 712 
 713   // Find the module's symbol
 714   ResourceMark rm(current);
 715   const char *module_name = module_sym->as_C_string();
 716   const char *path = get_exploded_module_path(module_name, false);
 717 
 718   struct stat st;
 719   if (os::stat(path, &st) == 0) {
 720     // Directory found
 721     ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);

 722     // If the path specification is valid, enter it into this module's list.
 723     // There is no need to check for duplicate modules in the exploded entry list,
 724     // since no two modules with the same name can be defined to the boot loader.
 725     // This is checked at module definition time in Modules::define_module.
 726     if (new_entry != nullptr) {
 727       ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 728       log_info(class, load)("path: %s", path);
 729 
 730       // If we are in preview mode, attempt to add a preview entry *before* the
 731       // new class path entry if a preview path exists.
 732       if (is_preview_enabled()) {
 733         const char* preview_path = get_preview_path(path);
 734         if (os::stat(preview_path, &st) == 0) {
 735           ClassPathEntry* preview_entry = create_class_path_entry(current, preview_path, &st);
 736           if (preview_entry != nullptr) {
 737             module_cpl->add_to_list(preview_entry);
 738             log_info(class, load)("preview path: %s", preview_path);
 739           }
 740         }
 741       }
 742 
 743       module_cpl->add_to_list(new_entry);
 744       {
 745         MutexLocker ml(current, Module_lock);
 746         _exploded_entries->push(module_cpl);
 747       }

 748     }
 749   }
 750 }
 751 
 752 jzfile* ClassLoader::open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread) {
 753   // enable call to C land
 754   ThreadToNativeFromVM ttn(thread);
 755   HandleMark hm(thread);
 756   return ZipLibrary::open(canonical_path, error_msg);
 757 }
 758 
 759 ClassPathEntry* ClassLoader::create_class_path_entry(JavaThread* current,
 760                                                      const char *path, const struct stat* st) {
 761   ClassPathEntry* new_entry = nullptr;
 762   if ((st->st_mode & S_IFMT) == S_IFREG) {
 763     ResourceMark rm(current);
 764     // Regular file, should be a zip file
 765     // Canonicalized filename
 766     const char* canonical_path = get_canonical_path(path, current);
 767     if (canonical_path == nullptr) {
 768       return nullptr;
 769     }
 770     char* error_msg = nullptr;
 771     jzfile* zip = open_zip_file(canonical_path, &error_msg, current);
 772     if (zip != nullptr && error_msg == nullptr) {
 773       new_entry = new ClassPathZipEntry(zip, path);
 774     } else {
 775       return nullptr;
 776     }
 777     log_info(class, path)("opened: %s", path);
 778     log_info(class, load)("opened: %s", path);
 779   } else {
 780     // Directory
 781     new_entry = new ClassPathDirEntry(path);
 782     log_info(class, load)("path: %s", path);
 783   }
 784   return new_entry;
 785 }
 786 
 787 
 788 // Create a class path zip entry for a given path (return null if not found
 789 // or zip/JAR file cannot be opened)
 790 ClassPathZipEntry* ClassLoader::create_class_path_zip_entry(const char *path) {
 791   // check for a regular file
 792   struct stat st;
 793   if (os::stat(path, &st) == 0) {
 794     if ((st.st_mode & S_IFMT) == S_IFREG) {
 795       JavaThread* thread = JavaThread::current();
 796       ResourceMark rm(thread);
 797       const char* canonical_path = get_canonical_path(path, thread);
 798       if (canonical_path != nullptr) {
 799         char* error_msg = nullptr;
 800         jzfile* zip = open_zip_file(canonical_path, &error_msg, thread);
 801         if (zip != nullptr && error_msg == nullptr) {
 802           // create using canonical path
 803           return new ClassPathZipEntry(zip, canonical_path);
 804         }
 805       }
 806     }
 807   }
 808   return nullptr;
 809 }
 810 
 811 // The boot append entries are added with a lock, and read lock free.
 812 void ClassLoader::add_to_boot_append_entries(ClassPathEntry *new_entry) {
 813   if (new_entry != nullptr) {
 814     MutexLocker ml(Bootclasspath_lock, Mutex::_no_safepoint_check_flag);
 815     if (_last_append_entry == nullptr) {
 816       _last_append_entry = new_entry;
 817       assert(first_append_entry() == nullptr, "boot loader's append class path entry list not empty");
 818       AtomicAccess::release_store(&_first_append_entry_list, new_entry);
 819     } else {
 820       _last_append_entry->set_next(new_entry);
 821       _last_append_entry = new_entry;
 822     }
 823   }
 824 }
 825 
 826 // Returns true IFF the file/dir exists and the entry was successfully created.
 827 bool ClassLoader::update_class_path_entry_list(JavaThread* current, const char *path) {
 828   struct stat st;
 829   if (os::stat(path, &st) == 0) {
 830     // File or directory found
 831     ClassPathEntry* new_entry = nullptr;
 832     new_entry = create_class_path_entry(current, path, &st);
 833     if (new_entry == nullptr) {
 834       return false;
 835     }
 836 
 837     // Do not reorder the bootclasspath which would break get_system_package().
 838     // Add new entry to linked list
 839     add_to_boot_append_entries(new_entry);
 840     return true;
 841   } else {
 842     return false;
 843   }
 844 }
 845 
 846 static void print_module_entry_table(const GrowableArray<ModuleClassPathList*>* const module_list) {
 847   ResourceMark rm;
 848   int num_of_entries = module_list->length();
 849   for (int i = 0; i < num_of_entries; i++) {
 850     ClassPathEntry* e;
 851     ModuleClassPathList* mpl = module_list->at(i);
 852     tty->print("%s=", mpl->module_name()->as_C_string());
 853     e = mpl->module_first_entry();
 854     while (e != nullptr) {
 855       tty->print("%s", e->name());
 856       e = e->next();
 857       if (e != nullptr) {
 858         tty->print("%s", os::path_separator());
 859       }
 860     }
 861     tty->print(" ;");
 862   }
 863 }
 864 
 865 void ClassLoader::print_bootclasspath() {
 866   ClassPathEntry* e;
 867   tty->print("[bootclasspath= ");
 868 
 869   // Print --patch-module module/path specifications first
 870   if (_patch_mod_entries != nullptr) {
 871     print_module_entry_table(_patch_mod_entries);
 872   }
 873 
 874   // [jimage | exploded modules build]
 875   if (has_jrt_entry()) {
 876     // Print the location of the java runtime image
 877     tty->print("%s ;", _jrt_entry->name());
 878   } else {
 879     // Print exploded module build path specifications
 880     if (_exploded_entries != nullptr) {
 881       print_module_entry_table(_exploded_entries);
 882     }
 883   }
 884 
 885   // appended entries
 886   e = first_append_entry();
 887   while (e != nullptr) {
 888     tty->print("%s ;", e->name());
 889     e = e->next();
 890   }
 891   tty->print_cr("]");
 892 }
 893 
 894 void* ClassLoader::dll_lookup(void* lib, const char* name, const char* path) {
 895   void* func = os::dll_lookup(lib, name);
 896   if (func == nullptr) {
 897     char msg[256] = "";
 898     jio_snprintf(msg, sizeof(msg), "Could not resolve \"%s\"", name);
 899     vm_exit_during_initialization(msg, path);
 900   }
 901   return func;
 902 }
 903 
 904 void ClassLoader::load_java_library() {
 905   assert(CanonicalizeEntry == nullptr, "should not load java library twice");
 906   if (is_vm_statically_linked()) {
 907     CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, os::lookup_function("JDK_Canonicalize"));
 908     assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize");
 909     return;
 910   }
 911 
 912   void *javalib_handle = os::native_java_library();
 913   if (javalib_handle == nullptr) {
 914     vm_exit_during_initialization("Unable to load java library", nullptr);
 915   }
 916 
 917   CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, dll_lookup(javalib_handle, "JDK_Canonicalize", nullptr));
 918   assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize in java library");
 919 }
 920 
 921 void ClassLoader::load_jimage_library() {
 922   assert(JImageOpen == nullptr, "should not load jimage library twice");
 923 
 924   if (is_vm_statically_linked()) {
 925       JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, os::lookup_function("JIMAGE_Open"));
 926       JImageClose = CAST_TO_FN_PTR(JImageClose_t, os::lookup_function("JIMAGE_Close"));
 927       JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, os::lookup_function("JIMAGE_FindResource"));
 928       JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, os::lookup_function("JIMAGE_GetResource"));
 929       assert(JImageOpen != nullptr && JImageClose != nullptr &&
 930             JImageFindResource != nullptr && JImageGetResource != nullptr,
 931             "could not lookup all jimage library functions");
 932       return;
 933     }
 934 
 935   char path[JVM_MAXPATHLEN];
 936   char ebuf[1024];
 937   void* handle = nullptr;
 938   if (os::dll_locate_lib(path, sizeof(path), Arguments::get_dll_dir(), "jimage")) {
 939     handle = os::dll_load(path, ebuf, sizeof ebuf);
 940   }
 941   if (handle == nullptr) {
 942     vm_exit_during_initialization("Unable to load jimage library", path);
 943   }
 944 
 945   JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, dll_lookup(handle, "JIMAGE_Open", path));
 946   JImageClose = CAST_TO_FN_PTR(JImageClose_t, dll_lookup(handle, "JIMAGE_Close", path));
 947   JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, dll_lookup(handle, "JIMAGE_FindResource", path));
 948   JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, dll_lookup(handle, "JIMAGE_GetResource", path));
 949   assert(JImageOpen != nullptr && JImageClose != nullptr &&
 950         JImageFindResource != nullptr && JImageGetResource != nullptr,
 951         "could not lookup all jimage library functions in jimage library");
 952 }
 953 
 954 int ClassLoader::crc32(int crc, const char* buf, int len) {
 955   return ZipLibrary::crc32(crc, (const jbyte*)buf, len);
 956 }
 957 
 958 oop ClassLoader::get_system_package(const char* name, TRAPS) {
 959   // Look up the name in the boot loader's package entry table.
 960   if (name != nullptr) {
 961     TempNewSymbol package_sym = SymbolTable::new_symbol(name);
 962     // Look for the package entry in the boot loader's package entry table.
 963     PackageEntry* package =
 964       ClassLoaderData::the_null_class_loader_data()->packages()->lookup_only(package_sym);
 965 
 966     // Return null if package does not exist or if no classes in that package
 967     // have been loaded.
 968     if (package != nullptr && package->has_loaded_class()) {
 969       ModuleEntry* module = package->module();
 970       if (module->location() != nullptr) {
 971         ResourceMark rm(THREAD);
 972         Handle ml = java_lang_String::create_from_str(
 973           module->location()->as_C_string(), THREAD);
 974         return ml();
 975       }
 976       // Return entry on boot loader class path.
 977       Handle cph = java_lang_String::create_from_str(
 978         ClassLoader::classpath_entry(package->classpath_index())->name(), THREAD);
 979       return cph();
 980     }
 981   }
 982   return nullptr;
 983 }
 984 
 985 refArrayOop ClassLoader::get_system_packages(TRAPS) {
 986   ResourceMark rm(THREAD);
 987   // List of pointers to PackageEntrys that have loaded classes.
 988   PackageEntryTable* pe_table =
 989       ClassLoaderData::the_null_class_loader_data()->packages();
 990   GrowableArray<PackageEntry*>* loaded_class_pkgs = pe_table->get_system_packages();
 991 
 992   // Allocate objArray and fill with java.lang.String
 993   refArrayOop r = oopFactory::new_refArray(vmClasses::String_klass(),
 994                                            loaded_class_pkgs->length(),
 995                                            CHECK_NULL);
 996   refArrayHandle result(THREAD, r);
 997   for (int x = 0; x < loaded_class_pkgs->length(); x++) {
 998     PackageEntry* package_entry = loaded_class_pkgs->at(x);
 999     Handle str = java_lang_String::create_from_symbol(package_entry->name(), CHECK_NULL);
1000     result->obj_at_put(x, str());
1001   }
1002   return result();
1003 }
1004 
1005 // caller needs ResourceMark
1006 const char* ClassLoader::file_name_for_class_name(const char* class_name,
1007                                                   int class_name_len) {
1008   assert(class_name != nullptr, "invariant");
1009   assert((int)strlen(class_name) == class_name_len, "invariant");
1010 
1011   static const char class_suffix[] = ".class";
1012   size_t class_suffix_len = sizeof(class_suffix);
1013 
1014   char* const file_name = NEW_RESOURCE_ARRAY(char,
1015                                              class_name_len +
1016                                              class_suffix_len); // includes term null
1017 
1018   strncpy(file_name, class_name, class_name_len);
1019   strncpy(&file_name[class_name_len], class_suffix, class_suffix_len);
1020 
1021   return file_name;
1022 }
1023 
1024 static ClassPathEntry* find_first_module_cpe(ModuleEntry* mod_entry,
1025                                              const GrowableArray<ModuleClassPathList*>* const module_list) {
1026   int num_of_entries = module_list->length();
1027   const Symbol* class_module_name = mod_entry->name();
1028 
1029   // Loop through all the modules in either the patch-module or exploded entries looking for module
1030   for (int i = 0; i < num_of_entries; i++) {
1031     ModuleClassPathList* module_cpl = module_list->at(i);
1032     Symbol* module_cpl_name = module_cpl->module_name();
1033 
1034     if (module_cpl_name->fast_compare(class_module_name) == 0) {
1035       // Class' module has been located.
1036       return module_cpl->module_first_entry();
1037     }
1038   }
1039   return nullptr;
1040 }
1041 
1042 
1043 // Search the module list for the class file stream based on the file name and java package
1044 ClassFileStream* ClassLoader::search_module_entries(JavaThread* current,
1045                                                     const GrowableArray<ModuleClassPathList*>* const module_list,
1046                                                     PackageEntry* pkg_entry, // Java package entry derived from the class name
1047                                                     const char* const file_name) {
1048   ClassFileStream* stream = nullptr;
1049 
1050   // Find the defining module in the boot loader's module entry table
1051   ModuleEntry* mod_entry = (pkg_entry != nullptr) ? pkg_entry->module() : nullptr;
1052 
1053   // If the module system has not defined java.base yet, then
1054   // classes loaded are assumed to be defined to java.base.
1055   // When java.base is eventually defined by the module system,
1056   // all packages of classes that have been previously loaded
1057   // are verified in ModuleEntryTable::verify_javabase_packages().
1058   if (!Universe::is_module_initialized() &&
1059       !ModuleEntryTable::javabase_defined() &&
1060       mod_entry == nullptr) {
1061     mod_entry = ModuleEntryTable::javabase_moduleEntry();
1062   }
1063 
1064   // The module must be a named module
1065   ClassPathEntry* e = nullptr;
1066   if (mod_entry != nullptr && mod_entry->is_named()) {
1067     if (module_list == _exploded_entries) {
1068       // The exploded build entries can be added to at any time so a lock is
1069       // needed when searching them.
1070       assert(!ClassLoader::has_jrt_entry(), "Must be exploded build");
1071       MutexLocker ml(current, Module_lock);
1072       e = find_first_module_cpe(mod_entry, module_list);
1073     } else {
1074       e = find_first_module_cpe(mod_entry, module_list);
1075     }
1076   }
1077 
1078   // Try to load the class from the module's ClassPathEntry list.
1079   while (e != nullptr) {
1080     stream = e->open_stream(current, file_name);
1081     // No context.check is required since CDS is not supported
1082     // for an exploded modules build or if --patch-module is specified.
1083     if (nullptr != stream) {
1084       return stream;
1085     }
1086     e = e->next();
1087   }
1088   // If the module was located, break out even if the class was not
1089   // located successfully from that module's ClassPathEntry list.
1090   // There will not be another valid entry for that module.
1091   return nullptr;
1092 }
1093 
1094 // Called by the boot classloader to load classes
1095 InstanceKlass* ClassLoader::load_class(Symbol* name, PackageEntry* pkg_entry, bool search_append_only, TRAPS) {
1096   assert(name != nullptr, "invariant");
1097 
1098   ResourceMark rm(THREAD);
1099   HandleMark hm(THREAD);
1100 
1101   const char* const class_name = name->as_C_string();
1102 
1103   EventMarkClassLoading m("Loading class %s", class_name);
1104 
1105   const char* const file_name = file_name_for_class_name(class_name,
1106                                                          name->utf8_length());
1107   assert(file_name != nullptr, "invariant");
1108 
1109   // Lookup stream for parsing .class file
1110   ClassFileStream* stream = nullptr;
1111   s2 classpath_index = 0;
1112   ClassPathEntry* e = nullptr;
1113   bool is_patched = false;
1114 
1115   // If search_append_only is true, boot loader visibility boundaries are
1116   // set to be _first_append_entry to the end. This includes:
1117   //   [-Xbootclasspath/a]; [jvmti appended entries]
1118   //
1119   // If search_append_only is false, boot loader visibility boundaries are
1120   // set to be the --patch-module entries plus the base piece. This includes:
1121   //   [--patch-module=<module>=<file>(<pathsep><file>)*]; [jimage | exploded module build]
1122   //
1123 
1124   // Load Attempt #1: --patch-module
1125   // Determine the class' defining module.  If it appears in the _patch_mod_entries,
1126   // attempt to load the class from those locations specific to the module.
1127   // Specifications to --patch-module can contain a partial number of classes
1128   // that are part of the overall module definition.  So if a particular class is not
1129   // found within its module specification, the search should continue to Load Attempt #2.
1130   // Note: The --patch-module entries are never searched if the boot loader's
1131   //       visibility boundary is limited to only searching the append entries.
1132   if (_patch_mod_entries != nullptr && !search_append_only) {
1133     // At CDS dump time, the --patch-module entries are ignored. That means a
1134     // class is still loaded from the runtime image even if it might
1135     // appear in the _patch_mod_entries. The runtime shared class visibility
1136     // check will determine if a shared class is visible based on the runtime
1137     // environment, including the runtime --patch-module setting.
1138     if (!Arguments::is_valhalla_enabled()) {
1139       // Dynamic dumping requires UseSharedSpaces to be enabled. Since --patch-module
1140       // is not supported with UseSharedSpaces, we can never come here during dynamic dumping.
1141       assert(!CDSConfig::is_dumping_archive(), "CDS doesn't support --patch-module during dumping");
1142     }
1143     if (Arguments::is_valhalla_enabled() || !CDSConfig::is_dumping_static_archive()) {
1144       stream = search_module_entries(THREAD, _patch_mod_entries, pkg_entry, file_name);
1145       if (stream != nullptr) {
1146         is_patched = true;
1147       }
1148     }
1149   }
1150 
1151   // Load Attempt #2: [jimage | exploded build]
1152   if (!search_append_only && (nullptr == stream)) {
1153     if (has_jrt_entry()) {
1154       e = _jrt_entry;
1155       stream = _jrt_entry->open_stream(THREAD, file_name);
1156     } else {
1157       // Exploded build - attempt to locate class in its defining module's location.
1158       assert(_exploded_entries != nullptr, "No exploded build entries present");
1159       assert(!CDSConfig::is_dumping_archive(), "CDS dumping doesn't support exploded build");
1160       stream = search_module_entries(THREAD, _exploded_entries, pkg_entry, file_name);
1161     }
1162   }
1163 
1164   // Load Attempt #3: [-Xbootclasspath/a]; [jvmti appended entries]
1165   if (search_append_only && (nullptr == stream)) {
1166     // For the boot loader append path search, the starting classpath_index
1167     // for the appended piece is always 1 to account for either the
1168     // _jrt_entry or the _exploded_entries.
1169     assert(classpath_index == 0, "The classpath_index has been incremented incorrectly");
1170     classpath_index = 1;
1171 
1172     e = first_append_entry();
1173     while (e != nullptr) {
1174       stream = e->open_stream(THREAD, file_name);
1175       if (nullptr != stream) {
1176         break;
1177       }
1178       e = e->next();
1179       ++classpath_index;
1180     }
1181   }
1182 
1183   if (nullptr == stream) {
1184     return nullptr;
1185   }
1186 
1187   ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
1188   Handle protection_domain;
1189   ClassLoadInfo cl_info(protection_domain);
1190 
1191   InstanceKlass* result = KlassFactory::create_from_stream(stream,
1192                                                            name,
1193                                                            loader_data,
1194                                                            cl_info,
1195                                                            CHECK_NULL);
1196   result->set_classpath_index(classpath_index);
1197   if (is_patched) {
1198     result->set_shared_classpath_index(0);
1199   }
1200   return result;
1201 }
1202 
1203 #if INCLUDE_CDS
1204 static const char* skip_uri_protocol(const char* source) {
1205   if (strncmp(source, "file:", 5) == 0) {
1206     // file: protocol path could start with file:/ or file:///
1207     // locate the char after all the forward slashes
1208     int offset = 5;
1209     while (*(source + offset) == '/') {
1210         offset++;
1211     }
1212     source += offset;
1213   // for non-windows platforms, move back one char as the path begins with a '/'
1214 #ifndef _WINDOWS
1215     source -= 1;
1216 #endif
1217   } else if (strncmp(source, "jrt:/", 5) == 0) {
1218     source += 5;
1219   }
1220   return source;
1221 }
1222 
1223 static char decode_percent_encoded(const char *str, size_t& index) {
1224   if (str[index] == '%'
1225       && isxdigit(str[index + 1])
1226       && isxdigit(str[index + 2])) {
1227     char hex[3];
1228     hex[0] = str[index + 1];
1229     hex[1] = str[index + 2];
1230     hex[2] = '\0';
1231     index += 2;
1232     return (char) strtol(hex, nullptr, 16);
1233   }
1234   return str[index];
1235 }
1236 
1237 char* ClassLoader::uri_to_path(const char* uri) {
1238   const size_t len = strlen(uri) + 1;
1239   char* path = NEW_RESOURCE_ARRAY(char, len);
1240 
1241   uri = skip_uri_protocol(uri);
1242 
1243   if (strncmp(uri, "//", 2) == 0) {
1244     // Skip the empty "authority" part
1245     uri += 2;
1246   }
1247 
1248 #ifdef _WINDOWS
1249   if (uri[0] == '/') {
1250     // Absolute path name on Windows does not begin with a slash
1251     uri += 1;
1252   }
1253 #endif
1254 
1255   size_t path_index = 0;
1256   for (size_t i = 0; i < strlen(uri); ++i) {
1257     char decoded = decode_percent_encoded(uri, i);
1258     path[path_index++] = decoded;
1259   }
1260   path[path_index] = '\0';
1261   return path;
1262 }
1263 
1264 // Record the shared classpath index and loader type for classes loaded
1265 // by the builtin loaders at dump time.
1266 void ClassLoader::record_result(JavaThread* current, InstanceKlass* ik,
1267                                 const ClassFileStream* stream, bool redefined) {
1268   assert(CDSConfig::is_dumping_archive(), "sanity");
1269   assert(stream != nullptr, "sanity");
1270 
1271   if (ik->is_hidden()) {
1272     record_hidden_class(ik);
1273     return;
1274   }
1275 
1276   if (ik->shared_classpath_index() == 0 && ik->defined_by_boot_loader()) {
1277     return;
1278   }
1279 
1280   oop loader = ik->class_loader();
1281   char* src = (char*)stream->source();
1282   if (src == nullptr) {
1283     ik->set_shared_classpath_index(-1); // unsupported location
1284     return;
1285   }
1286 
1287   if (!SystemDictionaryShared::is_builtin_loader(ik->class_loader_data())) {
1288     // A class loaded by a user-defined classloader.
1289     assert(ik->shared_classpath_index() < 0, "not assigned yet");
1290     ik->set_shared_classpath_index(UNREGISTERED_INDEX);
1291     SystemDictionaryShared::set_shared_class_misc_info(ik, (ClassFileStream*)stream);
1292     return;
1293   }
1294 
1295   assert(has_jrt_entry(), "CDS dumping does not support exploded JDK build");
1296 
1297   ResourceMark rm(current);
1298   int classpath_index = -1;
1299   bool found_invalid = false;
1300 
1301   PackageEntry* pkg_entry = ik->package();
1302 
1303   if (!AOTClassLocationConfig::dumptime_is_ready()) {
1304     // The shared path table is set up after module system initialization.
1305     // The path table contains no entry before that. Any classes loaded prior
1306     // to the setup of the shared path table must be from the modules image.
1307     assert(stream->from_boot_loader_modules_image(), "stream must be loaded by boot loader from modules image");
1308     classpath_index = 0;
1309   } else {
1310     // Save the path from the file: protocol or the module name from the jrt: protocol
1311     // if no protocol prefix is found, path is the same as stream->source(). This path
1312     // must be valid since the class has been successfully parsed.
1313     const char* path = ClassLoader::uri_to_path(src);
1314     assert(path != nullptr, "sanity");
1315     AOTClassLocationConfig::dumptime_iterate([&] (AOTClassLocation* cl) {
1316       int i = cl->index();
1317       // for index 0 and the stream->source() is the modules image or has the jrt: protocol.
1318       // The class must be from the runtime modules image.
1319       if (cl->is_modules_image() && (stream->from_boot_loader_modules_image() || string_starts_with(src, "jrt:"))) {
1320         classpath_index = i;
1321       } else if (os::same_files(cl->path(), path)) {
1322         // If the path (from the class stream source) is the same as the shared
1323         // class or module path, then we have a match.
1324         // src may come from the App/Platform class loaders, which would canonicalize
1325         // the file name. We cannot use strcmp to check for equality against cs->path().
1326         // We must use os::same_files (which is faster than canonicalizing cs->path()).
1327 
1328         // null pkg_entry and pkg_entry in an unnamed module implies the class
1329         // is from the -cp or boot loader append path which consists of -Xbootclasspath/a
1330         // and jvmti appended entries.
1331         if ((pkg_entry == nullptr) || (pkg_entry->in_unnamed_module())) {
1332           // Ensure the index is within the -cp range before assigning
1333           // to the classpath_index.
1334           if (SystemDictionary::is_system_class_loader(loader) && cl->from_app_classpath()) {
1335             classpath_index = i;
1336           } else {
1337             if (cl->from_boot_classpath()) {
1338               if (loader != nullptr) {
1339                 // Probably loaded by jdk/internal/loader/ClassLoaders$BootClassLoader. Don't archive
1340                 // such classes.
1341                 found_invalid = true;
1342               } else {
1343                 classpath_index = i;
1344               }
1345             }
1346           }
1347         } else {
1348           // A class from a named module from the --module-path. Ensure the index is
1349           // within the --module-path range before assigning to the classpath_index.
1350           if ((pkg_entry != nullptr) && !(pkg_entry->in_unnamed_module()) && cl->from_module_path()) {
1351             classpath_index = i;
1352           }
1353         }
1354       }
1355       if (classpath_index >= 0 || found_invalid) {
1356         return false; // Break the AOTClassLocationConfig::dumptime_iterate() loop.
1357       } else {
1358         return true; // Keep iterating
1359       }
1360     });
1361   }
1362 
1363   if (found_invalid) {
1364     assert(classpath_index == -1, "sanity");
1365   }
1366 
1367   const char* const class_name = ik->name()->as_C_string();
1368   const char* const file_name = file_name_for_class_name(class_name,
1369                                                          ik->name()->utf8_length());
1370   assert(file_name != nullptr, "invariant");
1371   record_result_for_builtin_loader(checked_cast<s2>(classpath_index), ik, redefined);
1372 }
1373 
1374 void ClassLoader::record_result_for_builtin_loader(s2 classpath_index, InstanceKlass* result, bool redefined) {
1375   assert(CDSConfig::is_dumping_archive(), "sanity");
1376 
1377   oop loader = result->class_loader();
1378   if (SystemDictionary::is_system_class_loader(loader)) {
1379     AOTClassLocationConfig::dumptime_set_has_app_classes();
1380   } else if (SystemDictionary::is_platform_class_loader(loader)) {
1381     AOTClassLocationConfig::dumptime_set_has_platform_classes();
1382   } else {
1383     precond(loader == nullptr);
1384   }
1385 
1386   if (CDSConfig::is_dumping_preimage_static_archive() || CDSConfig::is_dumping_dynamic_archive()) {
1387     if (!AOTClassLocationConfig::dumptime()->is_valid_classpath_index(classpath_index, result)) {
1388       classpath_index = -1;
1389     }
1390   }
1391 
1392   AOTClassLocationConfig::dumptime_update_max_used_index(classpath_index);
1393   result->set_shared_classpath_index(classpath_index);
1394 }
1395 
1396 void ClassLoader::record_hidden_class(InstanceKlass* ik) {
1397   assert(ik->is_hidden(), "must be");
1398 
1399   if (ik->defined_by_other_loaders()) {
1400     // We don't archive hidden classes for non-builtin loaders.
1401     return;
1402   }
1403 
1404   if (HeapShared::is_lambda_proxy_klass(ik)) {
1405     InstanceKlass* nest_host = ik->nest_host_not_null();
1406     ik->set_shared_classpath_index(nest_host->shared_classpath_index());
1407   } else if (HeapShared::is_lambda_form_klass(ik)) {
1408     ik->set_shared_classpath_index(0);
1409   } else {
1410     // Generated invoker classes.
1411     if (ik->defined_by_app_loader()) {
1412       ik->set_shared_classpath_index(AOTClassLocationConfig::dumptime()->app_cp_start_index());
1413     } else {
1414       ik->set_shared_classpath_index(0);
1415     }
1416   }
1417 }
1418 
1419 void ClassLoader::append_boot_classpath(ClassPathEntry* new_entry) {
1420   if (CDSConfig::is_using_archive()) {
1421     warning("Sharing is only supported for boot loader classes because bootstrap classpath has been appended");
1422     FileMapInfo::current_info()->set_has_platform_or_app_classes(false);
1423     if (DynamicArchive::is_mapped()) {
1424       FileMapInfo::dynamic_info()->set_has_platform_or_app_classes(false);
1425     }
1426   }
1427   add_to_boot_append_entries(new_entry);
1428 }
1429 #endif // INCLUDE_CDS
1430 
1431 // Initialize the class loader's access to methods in libzip.  Parse and
1432 // process the boot classpath into a list ClassPathEntry objects.  Once
1433 // this list has been created, it must not change order (see class PackageInfo)
1434 // it can be appended to and is by jvmti.
1435 
1436 void ClassLoader::initialize(TRAPS) {
1437   if (UsePerfData) {
1438     // jvmstat performance counters
1439     NEWPERFTICKCOUNTER(_perf_accumulated_time, SUN_CLS, "time");
1440     NEWPERFTICKCOUNTER(_perf_class_init_time, SUN_CLS, "classInitTime");
1441     NEWPERFTICKCOUNTER(_perf_class_init_selftime, SUN_CLS, "classInitTime.self");
1442     NEWPERFTICKCOUNTER(_perf_class_verify_time, SUN_CLS, "classVerifyTime");
1443     NEWPERFTICKCOUNTER(_perf_class_verify_selftime, SUN_CLS, "classVerifyTime.self");
1444     NEWPERFTICKCOUNTER(_perf_class_link_time, SUN_CLS, "classLinkedTime");
1445     NEWPERFTICKCOUNTER(_perf_class_link_selftime, SUN_CLS, "classLinkedTime.self");
1446     NEWPERFEVENTCOUNTER(_perf_classes_inited, SUN_CLS, "initializedClasses");
1447     NEWPERFEVENTCOUNTER(_perf_classes_linked, SUN_CLS, "linkedClasses");
1448     NEWPERFEVENTCOUNTER(_perf_classes_verified, SUN_CLS, "verifiedClasses");
1449 
1450     NEWPERFTICKCOUNTER(_perf_shared_classload_time, SUN_CLS, "sharedClassLoadTime");
1451     NEWPERFTICKCOUNTER(_perf_sys_classload_time, SUN_CLS, "sysClassLoadTime");
1452     NEWPERFTICKCOUNTER(_perf_app_classload_time, SUN_CLS, "appClassLoadTime");
1453     NEWPERFTICKCOUNTER(_perf_app_classload_selftime, SUN_CLS, "appClassLoadTime.self");
1454     NEWPERFEVENTCOUNTER(_perf_app_classload_count, SUN_CLS, "appClassLoadCount");
1455     NEWPERFTICKCOUNTER(_perf_define_appclasses, SUN_CLS, "defineAppClasses");
1456     NEWPERFTICKCOUNTER(_perf_define_appclass_time, SUN_CLS, "defineAppClassTime");
1457     NEWPERFTICKCOUNTER(_perf_define_appclass_selftime, SUN_CLS, "defineAppClassTime.self");
1458     NEWPERFBYTECOUNTER(_perf_app_classfile_bytes_read, SUN_CLS, "appClassBytes");
1459     NEWPERFBYTECOUNTER(_perf_sys_classfile_bytes_read, SUN_CLS, "sysClassBytes");
1460     NEWPERFEVENTCOUNTER(_unsafe_defineClassCallCounter, SUN_CLS, "unsafeDefineClassCalls");
1461     NEWPERFTICKCOUNTER(_perf_secondary_hash_time, SUN_CLS, "secondarySuperHashTime");
1462     NEWPERFTICKCOUNTER(_perf_change_wx_time, SUN_CLS, "changeWXTime");
1463 
1464     if (log_is_enabled(Info, perf, class, link)) {
1465       NEWPERFTICKCOUNTER(_perf_ik_link_methods_time, SUN_CLS, "linkMethodsTime");
1466       NEWPERFTICKCOUNTER(_perf_method_adapters_time, SUN_CLS, "makeAdaptersTime");
1467       NEWPERFEVENTCOUNTER(_perf_ik_link_methods_count, SUN_CLS, "linkMethodsCount");
1468       NEWPERFEVENTCOUNTER(_perf_method_adapters_count, SUN_CLS, "makeAdaptersCount");
1469 
1470       NEWPERFTICKCOUNTER(_perf_resolve_indy_time, SUN_CLS, "resolve_invokedynamic_time");
1471       NEWPERFTICKCOUNTER(_perf_resolve_invokehandle_time, SUN_CLS, "resolve_invokehandle_time");
1472       NEWPERFTICKCOUNTER(_perf_resolve_mh_time, SUN_CLS, "resolve_MethodHandle_time");
1473       NEWPERFTICKCOUNTER(_perf_resolve_mt_time, SUN_CLS, "resolve_MethodType_time");
1474 
1475       NEWPERFEVENTCOUNTER(_perf_resolve_indy_count, SUN_CLS, "resolve_invokedynamic_count");
1476       NEWPERFEVENTCOUNTER(_perf_resolve_invokehandle_count, SUN_CLS, "resolve_invokehandle_count");
1477       NEWPERFEVENTCOUNTER(_perf_resolve_mh_count, SUN_CLS, "resolve_MethodHandle_count");
1478       NEWPERFEVENTCOUNTER(_perf_resolve_mt_count, SUN_CLS, "resolve_MethodType_count");
1479     }
1480   }
1481 
1482   // lookup java library entry points
1483   load_java_library();
1484   // jimage library entry points are loaded below, in lookup_vm_options
1485   setup_bootstrap_search_path(THREAD);
1486 }
1487 











1488 // Lookup VM options embedded in the modules jimage file
1489 char* ClassLoader::lookup_vm_options() {

1490   char modules_path[JVM_MAXPATHLEN];
1491   const char* fileSep = os::file_separator();
1492 
1493   // Initialize jimage library entry points
1494   load_jimage_library();
1495 
1496   jio_snprintf(modules_path, JVM_MAXPATHLEN, "%s%slib%smodules", Arguments::get_java_home(), fileSep, fileSep);
1497   if (jimage_open(modules_path)) {
1498     // Special case where we lookup the options string *before* set_preview_mode() is called.
1499     // Since VM arguments have not been parsed, and the ClassPathImageEntry singleton
1500     // has not been created yet, we access the JImage file directly in non-preview mode.
1501     jlong size;
1502     JImageLocationRef location =
1503             jimage_find_resource(JAVA_BASE_NAME, "jdk/internal/vm/options", /* is_preview */ false, &size);
1504     if (location != 0) {
1505       char *options = NEW_C_HEAP_ARRAY(char, size+1, mtClass);
1506       (*JImageGetResource)(jimage_non_null(), location, options, size);
1507       options[size] = '\0';
1508       return options;
1509     }

1510   }
1511   return nullptr;
1512 }
1513 
1514 // Finishes initializing the JImageFile (if present) by setting the access mode.
1515 void ClassLoader::set_preview_mode(bool enable_preview) {
1516   assert(Preview_mode == PREVIEW_MODE_UNINITIALIZED, "set_preview_mode must not be called twice");
1517   Preview_mode = enable_preview ? PREVIEW_MODE_ENABLE_PREVIEW : PREVIEW_MODE_DEFAULT;
1518 }
1519 
1520 bool ClassLoader::is_module_observable(const char* module_name) {
1521   assert(JImageOpen != nullptr, "jimage library should have been opened");
1522   if (!jimage_exists()) {
1523     struct stat st;
1524     const char *path = get_exploded_module_path(module_name, true);
1525     bool res = os::stat(path, &st) == 0;
1526     FREE_C_HEAP_ARRAY(char, path);
1527     return res;
1528   }
1529   // We don't expect preview mode (i.e. --enable-preview) to affect module visibility.
1530   jlong size;
1531   return jimage_find_resource(module_name, "module-info.class", /* is_preview */ false, &size) != 0;

1532 }
1533 
1534 jlong ClassLoader::classloader_time_ms() {
1535   return UsePerfData ?
1536     Management::ticks_to_ms(_perf_accumulated_time->get_value()) : -1;
1537 }
1538 
1539 jlong ClassLoader::class_init_count() {
1540   return UsePerfData ? _perf_classes_inited->get_value() : -1;
1541 }
1542 
1543 jlong ClassLoader::class_init_time_ms() {
1544   return UsePerfData ?
1545     Management::ticks_to_ms(_perf_class_init_time->get_value()) : -1;
1546 }
1547 
1548 jlong ClassLoader::class_verify_time_ms() {
1549   return UsePerfData ?
1550     Management::ticks_to_ms(_perf_class_verify_time->get_value()) : -1;
1551 }
1552 
1553 jlong ClassLoader::class_link_count() {
1554   return UsePerfData ? _perf_classes_linked->get_value() : -1;
1555 }
1556 
1557 jlong ClassLoader::class_link_time_ms() {
1558   return UsePerfData ?
1559     Management::ticks_to_ms(_perf_class_link_time->get_value()) : -1;
1560 }
1561 
1562 int ClassLoader::compute_Object_vtable() {
1563   // hardwired for JDK1.2 -- would need to duplicate class file parsing
1564   // code to determine actual value from file
1565   // Would be value '11' if finals were in vtable
1566   int JDK_1_2_Object_vtable_size = 5;
1567   return JDK_1_2_Object_vtable_size * vtableEntry::size();
1568 }
1569 
1570 
1571 void classLoader_init1() {
1572   EXCEPTION_MARK;
1573   ClassLoader::initialize(THREAD);
1574   if (HAS_PENDING_EXCEPTION) {
1575     vm_exit_during_initialization("ClassLoader::initialize() failed unexpectedly");
1576   }
1577 }
1578 
1579 // Complete the ClassPathEntry setup for the boot loader
1580 void ClassLoader::classLoader_init2(JavaThread* current) {
1581   // Setup the list of module/path pairs for --patch-module processing
1582   // This must be done after the SymbolTable is created in order
1583   // to use fast_compare on module names instead of a string compare.
1584   if (Arguments::get_patch_mod_prefix() != nullptr) {
1585     setup_patch_mod_entries();
1586   }
1587 
1588   // Create the ModuleEntry for java.base (must occur after setup_patch_mod_entries
1589   // to successfully determine if java.base has been patched)
1590   create_javabase();
1591 
1592   // Setup the initial java.base/path pair for the exploded build entries.
1593   // As more modules are defined during module system initialization, more
1594   // entries will be added to the exploded build array.
1595   if (!has_jrt_entry()) {
1596     assert(!CDSConfig::is_dumping_archive(), "not supported with exploded module builds");
1597     assert(!CDSConfig::is_using_archive(), "UsedSharedSpaces not supported with exploded module builds");
1598     // Set up the boot loader's _exploded_entries list.  Note that this gets
1599     // done before loading any classes, by the same thread that will
1600     // subsequently do the first class load. So, no lock is needed for this.
1601     assert(_exploded_entries == nullptr, "Should only get initialized once");
1602     _exploded_entries = new (mtModule)
1603       GrowableArray<ModuleClassPathList*>(EXPLODED_ENTRY_SIZE, mtModule);
1604     add_to_exploded_build_list(current, vmSymbols::java_base());
1605   }
1606 }
1607 
1608 char* ClassLoader::get_canonical_path(const char* orig, Thread* thread) {
1609   assert(orig != nullptr, "bad arguments");
1610   // caller needs to allocate ResourceMark for the following output buffer
1611   char* canonical_path = NEW_RESOURCE_ARRAY_IN_THREAD(thread, char, JVM_MAXPATHLEN);
1612   ResourceMark rm(thread);
1613   // os::native_path writes into orig_copy
1614   char* orig_copy = ResourceArea::strdup(thread, orig);
1615   if ((CanonicalizeEntry)(os::native_path(orig_copy), canonical_path, JVM_MAXPATHLEN) < 0) {
1616     return nullptr;
1617   }
1618   return canonical_path;
1619 }
1620 
1621 void ClassLoader::create_javabase() {
1622   JavaThread* current = JavaThread::current();
1623 
1624   // Create java.base's module entry for the boot
1625   // class loader prior to loading j.l.Object.
1626   ClassLoaderData* null_cld = ClassLoaderData::the_null_class_loader_data();
1627 
1628   // Get module entry table
1629   ModuleEntryTable* null_cld_modules = null_cld->modules();
1630   if (null_cld_modules == nullptr) {
1631     vm_exit_during_initialization("No ModuleEntryTable for the boot class loader");
1632   }
1633 
1634   {
1635     MutexLocker ml(current, Module_lock);
1636     if (ModuleEntryTable::javabase_moduleEntry() == nullptr) {  // may have been inited by CDS.
1637       ModuleEntry* jb_module = null_cld_modules->locked_create_entry(Handle(),
1638                                false, vmSymbols::java_base(), nullptr, nullptr, null_cld);
1639       if (jb_module == nullptr) {
1640         vm_exit_during_initialization("Unable to create ModuleEntry for " JAVA_BASE_NAME);
1641       }
1642       ModuleEntryTable::set_javabase_moduleEntry(jb_module);
1643     }
1644   }
1645 }
1646 
1647 // Please keep following two functions at end of this file. With them placed at top or in middle of the file,
1648 // they could get inlined by aggressive compiler, an unknown trick, see bug 6966589.
1649 void PerfClassTraceTime::initialize() {
1650   if (!UsePerfData) return;
1651 
1652   if (_eventp != nullptr) {
1653     // increment the event counter
1654     _eventp->inc();
1655   }
1656 
1657   // stop the current active thread-local timer to measure inclusive time
1658   _prev_active_event = -1;
1659   for (int i=0; i < EVENT_TYPE_COUNT; i++) {
1660      if (_timers[i].is_active()) {
1661        assert(_prev_active_event == -1, "should have only one active timer");
1662        _prev_active_event = i;
1663        _timers[i].stop();
1664      }
1665   }
1666 
1667   if (_recursion_counters == nullptr || (_recursion_counters[_event_type])++ == 0) {
1668     // start the inclusive timer if not recursively called
1669     _t.start();
1670   }
1671 
1672   // start thread-local timer of the given event type
1673    if (!_timers[_event_type].is_active()) {
1674     _timers[_event_type].start();
1675   }
1676 }
1677 
1678 PerfClassTraceTime::~PerfClassTraceTime() {
1679   if (!UsePerfData) return;
1680 
1681   // stop the thread-local timer as the event completes
1682   // and resume the thread-local timer of the event next on the stack
1683   _timers[_event_type].stop();
1684   jlong selftime = _timers[_event_type].ticks();
1685 
1686   if (_prev_active_event >= 0) {
1687     _timers[_prev_active_event].start();
1688   }
1689 
1690   if (_recursion_counters != nullptr && --(_recursion_counters[_event_type]) > 0) return;
1691 
1692   // increment the counters only on the leaf call
1693   _t.stop();
1694   _timep->inc(_t.ticks());
1695   if (_selftimep != nullptr) {
1696     _selftimep->inc(selftime);
1697   }
1698   // add all class loading related event selftime to the accumulated time counter
1699   ClassLoader::perf_accumulated_time()->inc(selftime);
1700 
1701   // reset the timer
1702   _timers[_event_type].reset();
1703 }
--- EOF ---