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(_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, 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, 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(_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       log_info(class, path)("failed: %s, err: %s", path, error_msg);
 776       return nullptr;
 777     }
 778     log_info(class, path)("opened: %s", path);
 779     log_info(class, load)("opened: %s", path);
 780   } else {
 781     // Directory
 782     new_entry = new ClassPathDirEntry(path);
 783     log_info(class, load)("path: %s", path);
 784   }
 785   return new_entry;
 786 }
 787 
 788 
 789 // Create a class path zip entry for a given path (return null if not found
 790 // or zip/JAR file cannot be opened)
 791 ClassPathZipEntry* ClassLoader::create_class_path_zip_entry(const char *path) {
 792   // check for a regular file
 793   struct stat st;
 794   if (os::stat(path, &st) == 0) {
 795     if ((st.st_mode & S_IFMT) == S_IFREG) {
 796       JavaThread* thread = JavaThread::current();
 797       ResourceMark rm(thread);
 798       const char* canonical_path = get_canonical_path(path, thread);
 799       if (canonical_path != nullptr) {
 800         char* error_msg = nullptr;
 801         jzfile* zip = open_zip_file(canonical_path, &error_msg, thread);
 802         if (zip != nullptr && error_msg == nullptr) {
 803           // create using canonical path
 804           return new ClassPathZipEntry(zip, canonical_path);
 805         }
 806       }
 807     }
 808   }
 809   return nullptr;
 810 }
 811 
 812 // The boot append entries are added with a lock, and read lock free.
 813 void ClassLoader::add_to_boot_append_entries(ClassPathEntry *new_entry) {
 814   if (new_entry != nullptr) {
 815     MutexLocker ml(Bootclasspath_lock, Mutex::_no_safepoint_check_flag);
 816     if (_last_append_entry == nullptr) {
 817       _last_append_entry = new_entry;
 818       assert(first_append_entry() == nullptr, "boot loader's append class path entry list not empty");
 819       AtomicAccess::release_store(&_first_append_entry_list, new_entry);
 820     } else {
 821       _last_append_entry->set_next(new_entry);
 822       _last_append_entry = new_entry;
 823     }
 824   }
 825 }
 826 
 827 // Returns true IFF the file/dir exists and the entry was successfully created.
 828 bool ClassLoader::update_class_path_entry_list(JavaThread* current, const char *path) {
 829   struct stat st;
 830   if (os::stat(path, &st) == 0) {
 831     // File or directory found
 832     ClassPathEntry* new_entry = nullptr;
 833     new_entry = create_class_path_entry(current, path, &st);
 834     if (new_entry == nullptr) {
 835       return false;
 836     }
 837 
 838     // Do not reorder the bootclasspath which would break get_system_package().
 839     // Add new entry to linked list
 840     add_to_boot_append_entries(new_entry);
 841     return true;
 842   } else {
 843     return false;
 844   }
 845 }
 846 
 847 static void print_module_entry_table(const GrowableArray<ModuleClassPathList*>* const module_list) {
 848   ResourceMark rm;
 849   int num_of_entries = module_list->length();
 850   for (int i = 0; i < num_of_entries; i++) {
 851     ClassPathEntry* e;
 852     ModuleClassPathList* mpl = module_list->at(i);
 853     tty->print("%s=", mpl->module_name()->as_C_string());
 854     e = mpl->module_first_entry();
 855     while (e != nullptr) {
 856       tty->print("%s", e->name());
 857       e = e->next();
 858       if (e != nullptr) {
 859         tty->print("%s", os::path_separator());
 860       }
 861     }
 862     tty->print(" ;");
 863   }
 864 }
 865 
 866 void ClassLoader::print_bootclasspath() {
 867   ClassPathEntry* e;
 868   tty->print("[bootclasspath= ");
 869 
 870   // Print --patch-module module/path specifications first
 871   if (_patch_mod_entries != nullptr) {
 872     print_module_entry_table(_patch_mod_entries);
 873   }
 874 
 875   // [jimage | exploded modules build]
 876   if (has_jrt_entry()) {
 877     // Print the location of the java runtime image
 878     tty->print("%s ;", _jrt_entry->name());
 879   } else {
 880     // Print exploded module build path specifications
 881     if (_exploded_entries != nullptr) {
 882       print_module_entry_table(_exploded_entries);
 883     }
 884   }
 885 
 886   // appended entries
 887   e = first_append_entry();
 888   while (e != nullptr) {
 889     tty->print("%s ;", e->name());
 890     e = e->next();
 891   }
 892   tty->print_cr("]");
 893 }
 894 
 895 void* ClassLoader::dll_lookup(void* lib, const char* name, const char* path) {
 896   void* func = os::dll_lookup(lib, name);
 897   if (func == nullptr) {
 898     char msg[256] = "";
 899     jio_snprintf(msg, sizeof(msg), "Could not resolve \"%s\"", name);
 900     vm_exit_during_initialization(msg, path);
 901   }
 902   return func;
 903 }
 904 
 905 void ClassLoader::load_java_library() {
 906   assert(CanonicalizeEntry == nullptr, "should not load java library twice");
 907   if (is_vm_statically_linked()) {
 908     CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, os::lookup_function("JDK_Canonicalize"));
 909     assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize");
 910     return;
 911   }
 912 
 913   void *javalib_handle = os::native_java_library();
 914   if (javalib_handle == nullptr) {
 915     vm_exit_during_initialization("Unable to load java library", nullptr);
 916   }
 917 
 918   CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, dll_lookup(javalib_handle, "JDK_Canonicalize", nullptr));
 919   assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize in java library");
 920 }
 921 
 922 void ClassLoader::load_jimage_library() {
 923   assert(JImageOpen == nullptr, "should not load jimage library twice");
 924 
 925   if (is_vm_statically_linked()) {
 926       JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, os::lookup_function("JIMAGE_Open"));
 927       JImageClose = CAST_TO_FN_PTR(JImageClose_t, os::lookup_function("JIMAGE_Close"));
 928       JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, os::lookup_function("JIMAGE_FindResource"));
 929       JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, os::lookup_function("JIMAGE_GetResource"));
 930       assert(JImageOpen != nullptr && JImageClose != nullptr &&
 931             JImageFindResource != nullptr && JImageGetResource != nullptr,
 932             "could not lookup all jimage library functions");
 933       return;
 934     }
 935 
 936   char path[JVM_MAXPATHLEN];
 937   char ebuf[1024];
 938   void* handle = nullptr;
 939   if (os::dll_locate_lib(path, sizeof(path), Arguments::get_dll_dir(), "jimage")) {
 940     handle = os::dll_load(path, ebuf, sizeof ebuf);
 941   }
 942   if (handle == nullptr) {
 943     vm_exit_during_initialization("Unable to load jimage library", path);
 944   }
 945 
 946   JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, dll_lookup(handle, "JIMAGE_Open", path));
 947   JImageClose = CAST_TO_FN_PTR(JImageClose_t, dll_lookup(handle, "JIMAGE_Close", path));
 948   JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, dll_lookup(handle, "JIMAGE_FindResource", path));
 949   JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, dll_lookup(handle, "JIMAGE_GetResource", path));
 950   assert(JImageOpen != nullptr && JImageClose != nullptr &&
 951         JImageFindResource != nullptr && JImageGetResource != nullptr,
 952         "could not lookup all jimage library functions in jimage library");
 953 }
 954 
 955 int ClassLoader::crc32(int crc, const char* buf, int len) {
 956   return ZipLibrary::crc32(crc, (const jbyte*)buf, len);
 957 }
 958 
 959 oop ClassLoader::get_system_package(const char* name, TRAPS) {
 960   // Look up the name in the boot loader's package entry table.
 961   if (name != nullptr) {
 962     TempNewSymbol package_sym = SymbolTable::new_symbol(name);
 963     // Look for the package entry in the boot loader's package entry table.
 964     PackageEntry* package =
 965       ClassLoaderData::the_null_class_loader_data()->packages()->lookup_only(package_sym);
 966 
 967     // Return null if package does not exist or if no classes in that package
 968     // have been loaded.
 969     if (package != nullptr && package->has_loaded_class()) {
 970       ModuleEntry* module = package->module();
 971       if (module->location() != nullptr) {
 972         ResourceMark rm(THREAD);
 973         Handle ml = java_lang_String::create_from_str(
 974           module->location()->as_C_string(), THREAD);
 975         return ml();
 976       }
 977       // Return entry on boot loader class path.
 978       Handle cph = java_lang_String::create_from_str(
 979         ClassLoader::classpath_entry(package->classpath_index())->name(), THREAD);
 980       return cph();
 981     }
 982   }
 983   return nullptr;
 984 }
 985 
 986 refArrayOop ClassLoader::get_system_packages(TRAPS) {
 987   ResourceMark rm(THREAD);
 988   // List of pointers to PackageEntrys that have loaded classes.
 989   PackageEntryTable* pe_table =
 990       ClassLoaderData::the_null_class_loader_data()->packages();
 991   GrowableArray<PackageEntry*>* loaded_class_pkgs = pe_table->get_system_packages();
 992 
 993   // Allocate objArray and fill with java.lang.String
 994   refArrayOop r = oopFactory::new_refArray(vmClasses::String_klass(),
 995                                            loaded_class_pkgs->length(),
 996                                            CHECK_NULL);
 997   refArrayHandle result(THREAD, r);
 998   for (int x = 0; x < loaded_class_pkgs->length(); x++) {
 999     PackageEntry* package_entry = loaded_class_pkgs->at(x);
1000     Handle str = java_lang_String::create_from_symbol(package_entry->name(), CHECK_NULL);
1001     result->obj_at_put(x, str());
1002   }
1003   return result();
1004 }
1005 
1006 // caller needs ResourceMark
1007 const char* ClassLoader::file_name_for_class_name(const char* class_name,
1008                                                   int class_name_len) {
1009   assert(class_name != nullptr, "invariant");
1010   assert((int)strlen(class_name) == class_name_len, "invariant");
1011 
1012   static const char class_suffix[] = ".class";
1013   size_t class_suffix_len = sizeof(class_suffix);
1014 
1015   char* const file_name = NEW_RESOURCE_ARRAY(char,
1016                                              class_name_len +
1017                                              class_suffix_len); // includes term null
1018 
1019   strncpy(file_name, class_name, class_name_len);
1020   strncpy(&file_name[class_name_len], class_suffix, class_suffix_len);
1021 
1022   return file_name;
1023 }
1024 
1025 static ClassPathEntry* find_first_module_cpe(ModuleEntry* mod_entry,
1026                                              const GrowableArray<ModuleClassPathList*>* const module_list) {
1027   int num_of_entries = module_list->length();
1028   const Symbol* class_module_name = mod_entry->name();
1029 
1030   // Loop through all the modules in either the patch-module or exploded entries looking for module
1031   for (int i = 0; i < num_of_entries; i++) {
1032     ModuleClassPathList* module_cpl = module_list->at(i);
1033     Symbol* module_cpl_name = module_cpl->module_name();
1034 
1035     if (module_cpl_name->fast_compare(class_module_name) == 0) {
1036       // Class' module has been located.
1037       return module_cpl->module_first_entry();
1038     }
1039   }
1040   return nullptr;
1041 }
1042 
1043 
1044 // Search the module list for the class file stream based on the file name and java package
1045 ClassFileStream* ClassLoader::search_module_entries(JavaThread* current,
1046                                                     const GrowableArray<ModuleClassPathList*>* const module_list,
1047                                                     PackageEntry* pkg_entry, // Java package entry derived from the class name
1048                                                     const char* const file_name) {
1049   ClassFileStream* stream = nullptr;
1050 
1051   // Find the defining module in the boot loader's module entry table
1052   ModuleEntry* mod_entry = (pkg_entry != nullptr) ? pkg_entry->module() : nullptr;
1053 
1054   // If the module system has not defined java.base yet, then
1055   // classes loaded are assumed to be defined to java.base.
1056   // When java.base is eventually defined by the module system,
1057   // all packages of classes that have been previously loaded
1058   // are verified in ModuleEntryTable::verify_javabase_packages().
1059   if (!Universe::is_module_initialized() &&
1060       !ModuleEntryTable::javabase_defined() &&
1061       mod_entry == nullptr) {
1062     mod_entry = ModuleEntryTable::javabase_moduleEntry();
1063   }
1064 
1065   // The module must be a named module
1066   ClassPathEntry* e = nullptr;
1067   if (mod_entry != nullptr && mod_entry->is_named()) {
1068     if (module_list == _exploded_entries) {
1069       // The exploded build entries can be added to at any time so a lock is
1070       // needed when searching them.
1071       assert(!ClassLoader::has_jrt_entry(), "Must be exploded build");
1072       MutexLocker ml(current, Module_lock);
1073       e = find_first_module_cpe(mod_entry, module_list);
1074     } else {
1075       e = find_first_module_cpe(mod_entry, module_list);
1076     }
1077   }
1078 
1079   // Try to load the class from the module's ClassPathEntry list.
1080   while (e != nullptr) {
1081     stream = e->open_stream(current, file_name);
1082     // No context.check is required since CDS is not supported
1083     // for an exploded modules build or if --patch-module is specified.
1084     if (nullptr != stream) {
1085       return stream;
1086     }
1087     e = e->next();
1088   }
1089   // If the module was located, break out even if the class was not
1090   // located successfully from that module's ClassPathEntry list.
1091   // There will not be another valid entry for that module.
1092   return nullptr;
1093 }
1094 
1095 // Called by the boot classloader to load classes
1096 InstanceKlass* ClassLoader::load_class(Symbol* name, PackageEntry* pkg_entry, bool search_append_only, TRAPS) {
1097   assert(name != nullptr, "invariant");
1098 
1099   ResourceMark rm(THREAD);
1100   HandleMark hm(THREAD);
1101 
1102   const char* const class_name = name->as_C_string();
1103 
1104   EventMarkClassLoading m("Loading class %s", class_name);
1105 
1106   const char* const file_name = file_name_for_class_name(class_name,
1107                                                          name->utf8_length());
1108   assert(file_name != nullptr, "invariant");
1109 
1110   // Lookup stream for parsing .class file
1111   ClassFileStream* stream = nullptr;
1112   s2 classpath_index = 0;
1113   ClassPathEntry* e = nullptr;
1114   bool is_patched = false;
1115 
1116   // If search_append_only is true, boot loader visibility boundaries are
1117   // set to be _first_append_entry to the end. This includes:
1118   //   [-Xbootclasspath/a]; [jvmti appended entries]
1119   //
1120   // If search_append_only is false, boot loader visibility boundaries are
1121   // set to be the --patch-module entries plus the base piece. This includes:
1122   //   [--patch-module=<module>=<file>(<pathsep><file>)*]; [jimage | exploded module build]
1123   //
1124 
1125   // Load Attempt #1: --patch-module
1126   // Determine the class' defining module.  If it appears in the _patch_mod_entries,
1127   // attempt to load the class from those locations specific to the module.
1128   // Specifications to --patch-module can contain a partial number of classes
1129   // that are part of the overall module definition.  So if a particular class is not
1130   // found within its module specification, the search should continue to Load Attempt #2.
1131   // Note: The --patch-module entries are never searched if the boot loader's
1132   //       visibility boundary is limited to only searching the append entries.
1133   if (_patch_mod_entries != nullptr && !search_append_only) {
1134     // At CDS dump time, the --patch-module entries are ignored. That means a
1135     // class is still loaded from the runtime image even if it might
1136     // appear in the _patch_mod_entries. The runtime shared class visibility
1137     // check will determine if a shared class is visible based on the runtime
1138     // environment, including the runtime --patch-module setting.
1139     if (!Arguments::is_valhalla_enabled()) {
1140       // Dynamic dumping requires UseSharedSpaces to be enabled. Since --patch-module
1141       // is not supported with UseSharedSpaces, we can never come here during dynamic dumping.
1142       assert(!CDSConfig::is_dumping_archive(), "CDS doesn't support --patch-module during dumping");
1143     }
1144     if (Arguments::is_valhalla_enabled() || !CDSConfig::is_dumping_static_archive()) {
1145       stream = search_module_entries(THREAD, _patch_mod_entries, pkg_entry, file_name);
1146       if (stream != nullptr) {
1147         is_patched = true;
1148       }
1149     }
1150   }
1151 
1152   // Load Attempt #2: [jimage | exploded build]
1153   if (!search_append_only && (nullptr == stream)) {
1154     if (has_jrt_entry()) {
1155       e = _jrt_entry;
1156       stream = _jrt_entry->open_stream(THREAD, file_name);
1157     } else {
1158       // Exploded build - attempt to locate class in its defining module's location.
1159       assert(_exploded_entries != nullptr, "No exploded build entries present");
1160       assert(!CDSConfig::is_dumping_archive(), "CDS dumping doesn't support exploded build");
1161       stream = search_module_entries(THREAD, _exploded_entries, pkg_entry, file_name);
1162     }
1163   }
1164 
1165   // Load Attempt #3: [-Xbootclasspath/a]; [jvmti appended entries]
1166   if (search_append_only && (nullptr == stream)) {
1167     // For the boot loader append path search, the starting classpath_index
1168     // for the appended piece is always 1 to account for either the
1169     // _jrt_entry or the _exploded_entries.
1170     assert(classpath_index == 0, "The classpath_index has been incremented incorrectly");
1171     classpath_index = 1;
1172 
1173     e = first_append_entry();
1174     while (e != nullptr) {
1175       stream = e->open_stream(THREAD, file_name);
1176       if (nullptr != stream) {
1177         break;
1178       }
1179       e = e->next();
1180       ++classpath_index;
1181     }
1182   }
1183 
1184   if (nullptr == stream) {
1185     return nullptr;
1186   }
1187 
1188   ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
1189   Handle protection_domain;
1190   ClassLoadInfo cl_info(protection_domain);
1191 
1192   InstanceKlass* result = KlassFactory::create_from_stream(stream,
1193                                                            name,
1194                                                            loader_data,
1195                                                            cl_info,
1196                                                            CHECK_NULL);
1197   result->set_classpath_index(classpath_index);
1198   if (is_patched) {
1199     result->set_shared_classpath_index(0);
1200   }
1201   return result;
1202 }
1203 
1204 #if INCLUDE_CDS
1205 static const char* skip_uri_protocol(const char* source) {
1206   if (strncmp(source, "file:", 5) == 0) {
1207     // file: protocol path could start with file:/ or file:///
1208     // locate the char after all the forward slashes
1209     int offset = 5;
1210     while (*(source + offset) == '/') {
1211         offset++;
1212     }
1213     source += offset;
1214   // for non-windows platforms, move back one char as the path begins with a '/'
1215 #ifndef _WINDOWS
1216     source -= 1;
1217 #endif
1218   } else if (strncmp(source, "jrt:/", 5) == 0) {
1219     source += 5;
1220   }
1221   return source;
1222 }
1223 
1224 static char decode_percent_encoded(const char *str, size_t& index) {
1225   if (str[index] == '%'
1226       && isxdigit(str[index + 1])
1227       && isxdigit(str[index + 2])) {
1228     char hex[3];
1229     hex[0] = str[index + 1];
1230     hex[1] = str[index + 2];
1231     hex[2] = '\0';
1232     index += 2;
1233     return (char) strtol(hex, nullptr, 16);
1234   }
1235   return str[index];
1236 }
1237 
1238 char* ClassLoader::uri_to_path(const char* uri) {
1239   const size_t len = strlen(uri) + 1;
1240   char* path = NEW_RESOURCE_ARRAY(char, len);
1241 
1242   uri = skip_uri_protocol(uri);
1243 
1244   if (strncmp(uri, "//", 2) == 0) {
1245     // Skip the empty "authority" part
1246     uri += 2;
1247   }
1248 
1249 #ifdef _WINDOWS
1250   if (uri[0] == '/') {
1251     // Absolute path name on Windows does not begin with a slash
1252     uri += 1;
1253   }
1254 #endif
1255 
1256   size_t path_index = 0;
1257   for (size_t i = 0; i < strlen(uri); ++i) {
1258     char decoded = decode_percent_encoded(uri, i);
1259     path[path_index++] = decoded;
1260   }
1261   path[path_index] = '\0';
1262   return path;
1263 }
1264 
1265 // Record the shared classpath index and loader type for classes loaded
1266 // by the builtin loaders at dump time.
1267 void ClassLoader::record_result(JavaThread* current, InstanceKlass* ik,
1268                                 const ClassFileStream* stream, bool redefined) {
1269   assert(CDSConfig::is_dumping_archive(), "sanity");
1270   assert(stream != nullptr, "sanity");
1271 
1272   if (ik->is_hidden()) {
1273     record_hidden_class(ik);
1274     return;
1275   }
1276 
1277   if (ik->shared_classpath_index() == 0 && ik->defined_by_boot_loader()) {
1278     return;
1279   }
1280 
1281   oop loader = ik->class_loader();
1282   char* src = (char*)stream->source();
1283   if (src == nullptr) {
1284     ik->set_shared_classpath_index(-1); // unsupported location
1285     return;
1286   }
1287 
1288   if (!SystemDictionaryShared::is_builtin_loader(ik->class_loader_data())) {
1289     // A class loaded by a user-defined classloader.
1290     assert(ik->shared_classpath_index() < 0, "not assigned yet");
1291     ik->set_shared_classpath_index(UNREGISTERED_INDEX);
1292     SystemDictionaryShared::set_shared_class_misc_info(ik, (ClassFileStream*)stream);
1293     return;
1294   }
1295 
1296   assert(has_jrt_entry(), "CDS dumping does not support exploded JDK build");
1297 
1298   ResourceMark rm(current);
1299   int classpath_index = -1;
1300   bool found_invalid = false;
1301 
1302   PackageEntry* pkg_entry = ik->package();
1303 
1304   if (!AOTClassLocationConfig::dumptime_is_ready()) {
1305     // The shared path table is set up after module system initialization.
1306     // The path table contains no entry before that. Any classes loaded prior
1307     // to the setup of the shared path table must be from the modules image.
1308     assert(stream->from_boot_loader_modules_image(), "stream must be loaded by boot loader from modules image");
1309     classpath_index = 0;
1310   } else {
1311     // Save the path from the file: protocol or the module name from the jrt: protocol
1312     // if no protocol prefix is found, path is the same as stream->source(). This path
1313     // must be valid since the class has been successfully parsed.
1314     const char* path = ClassLoader::uri_to_path(src);
1315     assert(path != nullptr, "sanity");
1316     AOTClassLocationConfig::dumptime_iterate([&] (AOTClassLocation* cl) {
1317       int i = cl->index();
1318       // for index 0 and the stream->source() is the modules image or has the jrt: protocol.
1319       // The class must be from the runtime modules image.
1320       if (cl->is_modules_image() && (stream->from_boot_loader_modules_image() || string_starts_with(src, "jrt:"))) {
1321         classpath_index = i;
1322       } else if (os::same_files(cl->path(), path)) {
1323         // If the path (from the class stream source) is the same as the shared
1324         // class or module path, then we have a match.
1325         // src may come from the App/Platform class loaders, which would canonicalize
1326         // the file name. We cannot use strcmp to check for equality against cs->path().
1327         // We must use os::same_files (which is faster than canonicalizing cs->path()).
1328 
1329         // null pkg_entry and pkg_entry in an unnamed module implies the class
1330         // is from the -cp or boot loader append path which consists of -Xbootclasspath/a
1331         // and jvmti appended entries.
1332         if ((pkg_entry == nullptr) || (pkg_entry->in_unnamed_module())) {
1333           // Ensure the index is within the -cp range before assigning
1334           // to the classpath_index.
1335           if (SystemDictionary::is_system_class_loader(loader) && cl->from_app_classpath()) {
1336             classpath_index = i;
1337           } else {
1338             if (cl->from_boot_classpath()) {
1339               if (loader != nullptr) {
1340                 // Probably loaded by jdk/internal/loader/ClassLoaders$BootClassLoader. Don't archive
1341                 // such classes.
1342                 found_invalid = true;
1343               } else {
1344                 classpath_index = i;
1345               }
1346             }
1347           }
1348         } else {
1349           // A class from a named module from the --module-path. Ensure the index is
1350           // within the --module-path range before assigning to the classpath_index.
1351           if ((pkg_entry != nullptr) && !(pkg_entry->in_unnamed_module()) && cl->from_module_path()) {
1352             classpath_index = i;
1353           }
1354         }
1355       }
1356       if (classpath_index >= 0 || found_invalid) {
1357         return false; // Break the AOTClassLocationConfig::dumptime_iterate() loop.
1358       } else {
1359         return true; // Keep iterating
1360       }
1361     });
1362   }
1363 
1364   if (found_invalid) {
1365     assert(classpath_index == -1, "sanity");
1366   }
1367 
1368   const char* const class_name = ik->name()->as_C_string();
1369   const char* const file_name = file_name_for_class_name(class_name,
1370                                                          ik->name()->utf8_length());
1371   assert(file_name != nullptr, "invariant");
1372   record_result_for_builtin_loader(checked_cast<s2>(classpath_index), ik, redefined);
1373 }
1374 
1375 void ClassLoader::record_result_for_builtin_loader(s2 classpath_index, InstanceKlass* result, bool redefined) {
1376   assert(CDSConfig::is_dumping_archive(), "sanity");
1377 
1378   oop loader = result->class_loader();
1379   if (SystemDictionary::is_system_class_loader(loader)) {
1380     AOTClassLocationConfig::dumptime_set_has_app_classes();
1381   } else if (SystemDictionary::is_platform_class_loader(loader)) {
1382     AOTClassLocationConfig::dumptime_set_has_platform_classes();
1383   } else {
1384     precond(loader == nullptr);
1385   }
1386 
1387   if (CDSConfig::is_dumping_preimage_static_archive() || CDSConfig::is_dumping_dynamic_archive()) {
1388     if (!AOTClassLocationConfig::dumptime()->is_valid_classpath_index(classpath_index, result)) {
1389       classpath_index = -1;
1390     }
1391   }
1392 
1393   AOTClassLocationConfig::dumptime_update_max_used_index(classpath_index);
1394   result->set_shared_classpath_index(classpath_index);
1395 }
1396 
1397 void ClassLoader::record_hidden_class(InstanceKlass* ik) {
1398   assert(ik->is_hidden(), "must be");
1399 
1400   if (ik->defined_by_other_loaders()) {
1401     // We don't archive hidden classes for non-builtin loaders.
1402     return;
1403   }
1404 
1405   if (HeapShared::is_lambda_proxy_klass(ik)) {
1406     InstanceKlass* nest_host = ik->nest_host_not_null();
1407     ik->set_shared_classpath_index(nest_host->shared_classpath_index());
1408   } else if (HeapShared::is_lambda_form_klass(ik)) {
1409     ik->set_shared_classpath_index(0);
1410   } else {
1411     // Generated invoker classes.
1412     if (ik->defined_by_app_loader()) {
1413       ik->set_shared_classpath_index(AOTClassLocationConfig::dumptime()->app_cp_start_index());
1414     } else {
1415       ik->set_shared_classpath_index(0);
1416     }
1417   }
1418 }
1419 
1420 void ClassLoader::append_boot_classpath(ClassPathEntry* new_entry) {
1421   if (CDSConfig::is_using_archive()) {
1422     warning("Sharing is only supported for boot loader classes because bootstrap classpath has been appended");
1423     FileMapInfo::current_info()->set_has_platform_or_app_classes(false);
1424     if (DynamicArchive::is_mapped()) {
1425       FileMapInfo::dynamic_info()->set_has_platform_or_app_classes(false);
1426     }
1427   }
1428   add_to_boot_append_entries(new_entry);
1429 }
1430 #endif // INCLUDE_CDS
1431 
1432 // Initialize the class loader's access to methods in libzip.  Parse and
1433 // process the boot classpath into a list ClassPathEntry objects.  Once
1434 // this list has been created, it must not change order (see class PackageInfo)
1435 // it can be appended to and is by jvmti.
1436 
1437 void ClassLoader::initialize(TRAPS) {
1438   if (UsePerfData) {
1439     // jvmstat performance counters
1440     NEWPERFTICKCOUNTER(_perf_accumulated_time, SUN_CLS, "time");
1441     NEWPERFTICKCOUNTER(_perf_class_init_time, SUN_CLS, "classInitTime");
1442     NEWPERFTICKCOUNTER(_perf_class_init_selftime, SUN_CLS, "classInitTime.self");
1443     NEWPERFTICKCOUNTER(_perf_class_verify_time, SUN_CLS, "classVerifyTime");
1444     NEWPERFTICKCOUNTER(_perf_class_verify_selftime, SUN_CLS, "classVerifyTime.self");
1445     NEWPERFTICKCOUNTER(_perf_class_link_time, SUN_CLS, "classLinkedTime");
1446     NEWPERFTICKCOUNTER(_perf_class_link_selftime, SUN_CLS, "classLinkedTime.self");
1447     NEWPERFEVENTCOUNTER(_perf_classes_inited, SUN_CLS, "initializedClasses");
1448     NEWPERFEVENTCOUNTER(_perf_classes_linked, SUN_CLS, "linkedClasses");
1449     NEWPERFEVENTCOUNTER(_perf_classes_verified, SUN_CLS, "verifiedClasses");
1450 
1451     NEWPERFTICKCOUNTER(_perf_shared_classload_time, SUN_CLS, "sharedClassLoadTime");
1452     NEWPERFTICKCOUNTER(_perf_sys_classload_time, SUN_CLS, "sysClassLoadTime");
1453     NEWPERFTICKCOUNTER(_perf_app_classload_time, SUN_CLS, "appClassLoadTime");
1454     NEWPERFTICKCOUNTER(_perf_app_classload_selftime, SUN_CLS, "appClassLoadTime.self");
1455     NEWPERFEVENTCOUNTER(_perf_app_classload_count, SUN_CLS, "appClassLoadCount");
1456     NEWPERFTICKCOUNTER(_perf_define_appclasses, SUN_CLS, "defineAppClasses");
1457     NEWPERFTICKCOUNTER(_perf_define_appclass_time, SUN_CLS, "defineAppClassTime");
1458     NEWPERFTICKCOUNTER(_perf_define_appclass_selftime, SUN_CLS, "defineAppClassTime.self");
1459     NEWPERFBYTECOUNTER(_perf_app_classfile_bytes_read, SUN_CLS, "appClassBytes");
1460     NEWPERFBYTECOUNTER(_perf_sys_classfile_bytes_read, SUN_CLS, "sysClassBytes");
1461     NEWPERFEVENTCOUNTER(_unsafe_defineClassCallCounter, SUN_CLS, "unsafeDefineClassCalls");
1462     NEWPERFTICKCOUNTER(_perf_secondary_hash_time, SUN_CLS, "secondarySuperHashTime");
1463     NEWPERFTICKCOUNTER(_perf_change_wx_time, SUN_CLS, "changeWXTime");
1464 
1465     if (log_is_enabled(Info, perf, class, link)) {
1466       NEWPERFTICKCOUNTER(_perf_ik_link_methods_time, SUN_CLS, "linkMethodsTime");
1467       NEWPERFTICKCOUNTER(_perf_method_adapters_time, SUN_CLS, "makeAdaptersTime");
1468       NEWPERFEVENTCOUNTER(_perf_ik_link_methods_count, SUN_CLS, "linkMethodsCount");
1469       NEWPERFEVENTCOUNTER(_perf_method_adapters_count, SUN_CLS, "makeAdaptersCount");
1470 
1471       NEWPERFTICKCOUNTER(_perf_resolve_indy_time, SUN_CLS, "resolve_invokedynamic_time");
1472       NEWPERFTICKCOUNTER(_perf_resolve_invokehandle_time, SUN_CLS, "resolve_invokehandle_time");
1473       NEWPERFTICKCOUNTER(_perf_resolve_mh_time, SUN_CLS, "resolve_MethodHandle_time");
1474       NEWPERFTICKCOUNTER(_perf_resolve_mt_time, SUN_CLS, "resolve_MethodType_time");
1475 
1476       NEWPERFEVENTCOUNTER(_perf_resolve_indy_count, SUN_CLS, "resolve_invokedynamic_count");
1477       NEWPERFEVENTCOUNTER(_perf_resolve_invokehandle_count, SUN_CLS, "resolve_invokehandle_count");
1478       NEWPERFEVENTCOUNTER(_perf_resolve_mh_count, SUN_CLS, "resolve_MethodHandle_count");
1479       NEWPERFEVENTCOUNTER(_perf_resolve_mt_count, SUN_CLS, "resolve_MethodType_count");
1480     }
1481   }
1482 
1483   // lookup java library entry points
1484   load_java_library();
1485   // jimage library entry points are loaded below, in lookup_vm_options
1486   setup_bootstrap_search_path(THREAD);
1487 }
1488 











1489 // Lookup VM options embedded in the modules jimage file
1490 char* ClassLoader::lookup_vm_options() {

1491   char modules_path[JVM_MAXPATHLEN];
1492   const char* fileSep = os::file_separator();
1493 
1494   // Initialize jimage library entry points
1495   load_jimage_library();
1496 
1497   jio_snprintf(modules_path, JVM_MAXPATHLEN, "%s%slib%smodules", Arguments::get_java_home(), fileSep, fileSep);
1498   if (jimage_open(modules_path)) {
1499     // Special case where we lookup the options string *before* set_preview_mode() is called.
1500     // Since VM arguments have not been parsed, and the ClassPathImageEntry singleton
1501     // has not been created yet, we access the JImage file directly in non-preview mode.
1502     jlong size;
1503     JImageLocationRef location =
1504             jimage_find_resource(JAVA_BASE_NAME, "jdk/internal/vm/options", /* is_preview */ false, &size);
1505     if (location != 0) {
1506       char *options = NEW_C_HEAP_ARRAY(char, size+1, mtClass);
1507       (*JImageGetResource)(jimage_non_null(), location, options, size);
1508       options[size] = '\0';
1509       return options;
1510     }

1511   }
1512   return nullptr;
1513 }
1514 
1515 // Finishes initializing the JImageFile (if present) by setting the access mode.
1516 void ClassLoader::set_preview_mode(bool enable_preview) {
1517   assert(Preview_mode == PREVIEW_MODE_UNINITIALIZED, "set_preview_mode must not be called twice");
1518   Preview_mode = enable_preview ? PREVIEW_MODE_ENABLE_PREVIEW : PREVIEW_MODE_DEFAULT;
1519 }
1520 
1521 bool ClassLoader::is_module_observable(const char* module_name) {
1522   assert(JImageOpen != nullptr, "jimage library should have been opened");
1523   if (!jimage_exists()) {
1524     struct stat st;
1525     const char *path = get_exploded_module_path(module_name, true);
1526     bool res = os::stat(path, &st) == 0;
1527     FREE_C_HEAP_ARRAY(path);
1528     return res;
1529   }
1530   // We don't expect preview mode (i.e. --enable-preview) to affect module visibility.
1531   jlong size;
1532   return jimage_find_resource(module_name, "module-info.class", /* is_preview */ false, &size) != 0;

1533 }
1534 
1535 jlong ClassLoader::classloader_time_ms() {
1536   return UsePerfData ?
1537     Management::ticks_to_ms(_perf_accumulated_time->get_value()) : -1;
1538 }
1539 
1540 jlong ClassLoader::class_init_count() {
1541   return UsePerfData ? _perf_classes_inited->get_value() : -1;
1542 }
1543 
1544 jlong ClassLoader::class_init_time_ms() {
1545   return UsePerfData ?
1546     Management::ticks_to_ms(_perf_class_init_time->get_value()) : -1;
1547 }
1548 
1549 jlong ClassLoader::class_verify_time_ms() {
1550   return UsePerfData ?
1551     Management::ticks_to_ms(_perf_class_verify_time->get_value()) : -1;
1552 }
1553 
1554 jlong ClassLoader::class_link_count() {
1555   return UsePerfData ? _perf_classes_linked->get_value() : -1;
1556 }
1557 
1558 jlong ClassLoader::class_link_time_ms() {
1559   return UsePerfData ?
1560     Management::ticks_to_ms(_perf_class_link_time->get_value()) : -1;
1561 }
1562 
1563 int ClassLoader::compute_Object_vtable() {
1564   // hardwired for JDK1.2 -- would need to duplicate class file parsing
1565   // code to determine actual value from file
1566   // Would be value '11' if finals were in vtable
1567   int JDK_1_2_Object_vtable_size = 5;
1568   return JDK_1_2_Object_vtable_size * vtableEntry::size();
1569 }
1570 
1571 
1572 void classLoader_init1() {
1573   EXCEPTION_MARK;
1574   ClassLoader::initialize(THREAD);
1575   if (HAS_PENDING_EXCEPTION) {
1576     vm_exit_during_initialization("ClassLoader::initialize() failed unexpectedly");
1577   }
1578 }
1579 
1580 // Complete the ClassPathEntry setup for the boot loader
1581 void ClassLoader::classLoader_init2(JavaThread* current) {
1582   // Setup the list of module/path pairs for --patch-module processing
1583   // This must be done after the SymbolTable is created in order
1584   // to use fast_compare on module names instead of a string compare.
1585   if (Arguments::get_patch_mod_prefix() != nullptr) {
1586     setup_patch_mod_entries();
1587   }
1588 
1589   // Create the ModuleEntry for java.base (must occur after setup_patch_mod_entries
1590   // to successfully determine if java.base has been patched)
1591   create_javabase();
1592 
1593   // Setup the initial java.base/path pair for the exploded build entries.
1594   // As more modules are defined during module system initialization, more
1595   // entries will be added to the exploded build array.
1596   if (!has_jrt_entry()) {
1597     assert(!CDSConfig::is_dumping_archive(), "not supported with exploded module builds");
1598     assert(!CDSConfig::is_using_archive(), "UsedSharedSpaces not supported with exploded module builds");
1599     // Set up the boot loader's _exploded_entries list.  Note that this gets
1600     // done before loading any classes, by the same thread that will
1601     // subsequently do the first class load. So, no lock is needed for this.
1602     assert(_exploded_entries == nullptr, "Should only get initialized once");
1603     _exploded_entries = new (mtModule)
1604       GrowableArray<ModuleClassPathList*>(EXPLODED_ENTRY_SIZE, mtModule);
1605     add_to_exploded_build_list(current, vmSymbols::java_base());
1606   }
1607 }
1608 
1609 char* ClassLoader::get_canonical_path(const char* orig, Thread* thread) {
1610   assert(orig != nullptr, "bad arguments");
1611   // caller needs to allocate ResourceMark for the following output buffer
1612   char* canonical_path = NEW_RESOURCE_ARRAY_IN_THREAD(thread, char, JVM_MAXPATHLEN);
1613   ResourceMark rm(thread);
1614   // os::native_path writes into orig_copy
1615   char* orig_copy = ResourceArea::strdup(thread, orig);
1616   if ((CanonicalizeEntry)(os::native_path(orig_copy), canonical_path, JVM_MAXPATHLEN) < 0) {
1617     return nullptr;
1618   }
1619   return canonical_path;
1620 }
1621 
1622 void ClassLoader::create_javabase() {
1623   JavaThread* current = JavaThread::current();
1624 
1625   // Create java.base's module entry for the boot
1626   // class loader prior to loading j.l.Object.
1627   ClassLoaderData* null_cld = ClassLoaderData::the_null_class_loader_data();
1628 
1629   // Get module entry table
1630   ModuleEntryTable* null_cld_modules = null_cld->modules();
1631   if (null_cld_modules == nullptr) {
1632     vm_exit_during_initialization("No ModuleEntryTable for the boot class loader");
1633   }
1634 
1635   {
1636     MutexLocker ml(current, Module_lock);
1637     if (ModuleEntryTable::javabase_moduleEntry() == nullptr) {  // may have been inited by CDS.
1638       ModuleEntry* jb_module = null_cld_modules->locked_create_entry(Handle(),
1639                                false, vmSymbols::java_base(), nullptr, nullptr, null_cld);
1640       if (jb_module == nullptr) {
1641         vm_exit_during_initialization("Unable to create ModuleEntry for " JAVA_BASE_NAME);
1642       }
1643       ModuleEntryTable::set_javabase_moduleEntry(jb_module);
1644     }
1645   }
1646 }
1647 
1648 // Please keep following two functions at end of this file. With them placed at top or in middle of the file,
1649 // they could get inlined by aggressive compiler, an unknown trick, see bug 6966589.
1650 void PerfClassTraceTime::initialize() {
1651   if (!UsePerfData) return;
1652 
1653   if (_eventp != nullptr) {
1654     // increment the event counter
1655     _eventp->inc();
1656   }
1657 
1658   // stop the current active thread-local timer to measure inclusive time
1659   _prev_active_event = -1;
1660   for (int i=0; i < EVENT_TYPE_COUNT; i++) {
1661      if (_timers[i].is_active()) {
1662        assert(_prev_active_event == -1, "should have only one active timer");
1663        _prev_active_event = i;
1664        _timers[i].stop();
1665      }
1666   }
1667 
1668   if (_recursion_counters == nullptr || (_recursion_counters[_event_type])++ == 0) {
1669     // start the inclusive timer if not recursively called
1670     _t.start();
1671   }
1672 
1673   // start thread-local timer of the given event type
1674    if (!_timers[_event_type].is_active()) {
1675     _timers[_event_type].start();
1676   }
1677 }
1678 
1679 PerfClassTraceTime::~PerfClassTraceTime() {
1680   if (!UsePerfData) return;
1681 
1682   // stop the thread-local timer as the event completes
1683   // and resume the thread-local timer of the event next on the stack
1684   _timers[_event_type].stop();
1685   jlong selftime = _timers[_event_type].ticks();
1686 
1687   if (_prev_active_event >= 0) {
1688     _timers[_prev_active_event].start();
1689   }
1690 
1691   if (_recursion_counters != nullptr && --(_recursion_counters[_event_type]) > 0) return;
1692 
1693   // increment the counters only on the leaf call
1694   _t.stop();
1695   _timep->inc(_t.ticks());
1696   if (_selftimep != nullptr) {
1697     _selftimep->inc(selftime);
1698   }
1699   // add all class loading related event selftime to the accumulated time counter
1700   ClassLoader::perf_accumulated_time()->inc(selftime);
1701 
1702   // reset the timer
1703   _timers[_event_type].reset();
1704 }
--- EOF ---