1 /*
   2  * Copyright (c) 2012, 2025, 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/aotArtifactFinder.hpp"
  26 #include "cds/aotClassInitializer.hpp"
  27 #include "cds/aotClassLinker.hpp"
  28 #include "cds/aotClassLocation.hpp"
  29 #include "cds/aotConstantPoolResolver.hpp"
  30 #include "cds/aotLinkedClassBulkLoader.hpp"
  31 #include "cds/aotReferenceObjSupport.hpp"
  32 #include "cds/archiveBuilder.hpp"
  33 #include "cds/archiveHeapLoader.hpp"
  34 #include "cds/archiveHeapWriter.hpp"
  35 #include "cds/cds_globals.hpp"
  36 #include "cds/cdsConfig.hpp"
  37 #include "cds/cdsProtectionDomain.hpp"
  38 #include "cds/classListParser.hpp"
  39 #include "cds/classListWriter.hpp"
  40 #include "cds/cppVtables.hpp"
  41 #include "cds/dumpAllocStats.hpp"
  42 #include "cds/dynamicArchive.hpp"
  43 #include "cds/filemap.hpp"
  44 #include "cds/finalImageRecipes.hpp"
  45 #include "cds/heapShared.hpp"
  46 #include "cds/lambdaFormInvokers.hpp"
  47 #include "cds/lambdaProxyClassDictionary.hpp"
  48 #include "cds/metaspaceShared.hpp"
  49 #include "classfile/classLoaderDataGraph.hpp"
  50 #include "classfile/classLoaderDataShared.hpp"
  51 #include "classfile/classLoaderExt.hpp"
  52 #include "classfile/javaClasses.inline.hpp"
  53 #include "classfile/loaderConstraints.hpp"
  54 #include "classfile/modules.hpp"
  55 #include "classfile/placeholders.hpp"
  56 #include "classfile/stringTable.hpp"
  57 #include "classfile/symbolTable.hpp"
  58 #include "classfile/systemDictionary.hpp"
  59 #include "classfile/systemDictionaryShared.hpp"
  60 #include "classfile/vmClasses.hpp"
  61 #include "classfile/vmSymbols.hpp"
  62 #include "code/codeCache.hpp"
  63 #include "gc/shared/gcVMOperations.hpp"
  64 #include "interpreter/bytecodeStream.hpp"
  65 #include "interpreter/bytecodes.hpp"
  66 #include "jvm_io.h"
  67 #include "logging/log.hpp"
  68 #include "logging/logMessage.hpp"
  69 #include "logging/logStream.hpp"
  70 #include "memory/memoryReserver.hpp"
  71 #include "memory/metaspace.hpp"
  72 #include "memory/metaspaceClosure.hpp"
  73 #include "memory/resourceArea.hpp"
  74 #include "memory/universe.hpp"
  75 #include "nmt/memTracker.hpp"
  76 #include "oops/compressedKlass.hpp"
  77 #include "oops/instanceMirrorKlass.hpp"
  78 #include "oops/klass.inline.hpp"
  79 #include "oops/objArrayOop.hpp"
  80 #include "oops/oop.inline.hpp"
  81 #include "oops/oopHandle.hpp"
  82 #include "prims/jvmtiExport.hpp"
  83 #include "runtime/arguments.hpp"
  84 #include "runtime/globals.hpp"
  85 #include "runtime/globals_extension.hpp"
  86 #include "runtime/handles.inline.hpp"
  87 #include "runtime/javaCalls.hpp"
  88 #include "runtime/os.inline.hpp"
  89 #include "runtime/safepointVerifiers.hpp"
  90 #include "runtime/sharedRuntime.hpp"
  91 #include "runtime/vmOperations.hpp"
  92 #include "runtime/vmThread.hpp"
  93 #include "sanitizers/leak.hpp"
  94 #include "utilities/align.hpp"
  95 #include "utilities/bitMap.inline.hpp"
  96 #include "utilities/defaultStream.hpp"
  97 #include "utilities/macros.hpp"
  98 #include "utilities/ostream.hpp"
  99 #include "utilities/resourceHash.hpp"
 100 
 101 #include <sys/stat.h>
 102 
 103 ReservedSpace MetaspaceShared::_symbol_rs;
 104 VirtualSpace MetaspaceShared::_symbol_vs;
 105 bool MetaspaceShared::_archive_loading_failed = false;
 106 bool MetaspaceShared::_remapped_readwrite = false;
 107 void* MetaspaceShared::_shared_metaspace_static_top = nullptr;
 108 intx MetaspaceShared::_relocation_delta;
 109 char* MetaspaceShared::_requested_base_address;
 110 Array<Method*>* MetaspaceShared::_archived_method_handle_intrinsics = nullptr;
 111 bool MetaspaceShared::_use_optimized_module_handling = true;
 112 
 113 // The CDS archive is divided into the following regions:
 114 //     rw  - read-write metadata
 115 //     ro  - read-only metadata and read-only tables
 116 //     hp  - heap region
 117 //     bm  - bitmap for relocating the above 7 regions.
 118 //
 119 // The rw and ro regions are linearly allocated, in the order of rw->ro.
 120 // These regions are aligned with MetaspaceShared::core_region_alignment().
 121 //
 122 // These 2 regions are populated in the following steps:
 123 // [0] All classes are loaded in MetaspaceShared::preload_classes(). All metadata are
 124 //     temporarily allocated outside of the shared regions.
 125 // [1] We enter a safepoint and allocate a buffer for the rw/ro regions.
 126 // [2] C++ vtables are copied into the rw region.
 127 // [3] ArchiveBuilder copies RW metadata into the rw region.
 128 // [4] ArchiveBuilder copies RO metadata into the ro region.
 129 // [5] SymbolTable, StringTable, SystemDictionary, and a few other read-only data
 130 //     are copied into the ro region as read-only tables.
 131 //
 132 // The heap region is written by HeapShared::write_heap().
 133 //
 134 // The bitmap region is used to relocate the ro/rw/hp regions.
 135 
 136 static DumpRegion _symbol_region("symbols");
 137 
 138 char* MetaspaceShared::symbol_space_alloc(size_t num_bytes) {
 139   return _symbol_region.allocate(num_bytes);
 140 }
 141 
 142 // os::vm_allocation_granularity() is usually 4K for most OSes. However, some platforms
 143 // such as linux-aarch64 and macos-x64 ...
 144 // it can be either 4K or 64K and on macos-aarch64 it is 16K. To generate archives that are
 145 // compatible for both settings, an alternative cds core region alignment can be enabled
 146 // at building time:
 147 //   --enable-compactible-cds-alignment
 148 // Upon successful configuration, the compactible alignment then can be defined in:
 149 //   os_linux_aarch64.cpp
 150 //   os_bsd_x86.cpp
 151 size_t MetaspaceShared::core_region_alignment() {
 152   return os::cds_core_region_alignment();
 153 }
 154 
 155 size_t MetaspaceShared::protection_zone_size() {
 156   return os::cds_core_region_alignment();
 157 }
 158 
 159 static bool shared_base_valid(char* shared_base) {
 160   // We check user input for SharedBaseAddress at dump time.
 161 
 162   // At CDS runtime, "shared_base" will be the (attempted) mapping start. It will also
 163   // be the encoding base, since the headers of archived base objects (and with Lilliput,
 164   // the prototype mark words) carry pre-computed narrow Klass IDs that refer to the mapping
 165   // start as base.
 166   //
 167   // On AARCH64, The "shared_base" may not be later usable as encoding base, depending on the
 168   // total size of the reserved area and the precomputed_narrow_klass_shift. This is checked
 169   // before reserving memory.  Here we weed out values already known to be invalid later.
 170   return AARCH64_ONLY(is_aligned(shared_base, 4 * G)) NOT_AARCH64(true);
 171 }
 172 
 173 class DumpClassListCLDClosure : public CLDClosure {
 174   static const int INITIAL_TABLE_SIZE = 1987;
 175   static const int MAX_TABLE_SIZE = 61333;
 176 
 177   fileStream *_stream;
 178   ResizeableResourceHashtable<InstanceKlass*, bool,
 179                               AnyObj::C_HEAP, mtClassShared> _dumped_classes;
 180 
 181   void dump(InstanceKlass* ik) {
 182     bool created;
 183     _dumped_classes.put_if_absent(ik, &created);
 184     if (!created) {
 185       return;
 186     }
 187     if (_dumped_classes.maybe_grow()) {
 188       log_info(cds, hashtables)("Expanded _dumped_classes table to %d", _dumped_classes.table_size());
 189     }
 190     if (ik->java_super()) {
 191       dump(ik->java_super());
 192     }
 193     Array<InstanceKlass*>* interfaces = ik->local_interfaces();
 194     int len = interfaces->length();
 195     for (int i = 0; i < len; i++) {
 196       dump(interfaces->at(i));
 197     }
 198     ClassListWriter::write_to_stream(ik, _stream);
 199   }
 200 
 201 public:
 202   DumpClassListCLDClosure(fileStream* f)
 203   : CLDClosure(), _dumped_classes(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE) {
 204     _stream = f;
 205   }
 206 
 207   void do_cld(ClassLoaderData* cld) {
 208     for (Klass* klass = cld->klasses(); klass != nullptr; klass = klass->next_link()) {
 209       if (klass->is_instance_klass()) {
 210         dump(InstanceKlass::cast(klass));
 211       }
 212     }
 213   }
 214 };
 215 
 216 void MetaspaceShared::dump_loaded_classes(const char* file_name, TRAPS) {
 217   fileStream stream(file_name, "w");
 218   if (stream.is_open()) {
 219     MutexLocker lock(ClassLoaderDataGraph_lock);
 220     MutexLocker lock2(ClassListFile_lock, Mutex::_no_safepoint_check_flag);
 221     DumpClassListCLDClosure collect_classes(&stream);
 222     ClassLoaderDataGraph::loaded_cld_do(&collect_classes);
 223   } else {
 224     THROW_MSG(vmSymbols::java_io_IOException(), "Failed to open file");
 225   }
 226 }
 227 
 228 static bool shared_base_too_high(char* specified_base, char* aligned_base, size_t cds_max) {
 229   // Caller should have checked that aligned_base was successfully aligned and is not nullptr.
 230   // Comparing specified_base with nullptr is UB.
 231   assert(aligned_base != nullptr, "sanity");
 232   assert(aligned_base >= specified_base, "sanity");
 233 
 234   if (max_uintx - uintx(aligned_base) < uintx(cds_max)) {
 235     // Not enough address space to hold an archive of cds_max bytes from aligned_base.
 236     return true;
 237   } else {
 238     return false;
 239   }
 240 }
 241 
 242 static char* compute_shared_base(size_t cds_max) {
 243   char* specified_base = (char*)SharedBaseAddress;
 244   size_t alignment = MetaspaceShared::core_region_alignment();
 245   if (UseCompressedClassPointers) {
 246     alignment = MAX2(alignment, Metaspace::reserve_alignment());
 247   }
 248 
 249   if (SharedBaseAddress == 0) {
 250     // Special meaning of -XX:SharedBaseAddress=0 -> Always map archive at os-selected address.
 251     return specified_base;
 252   }
 253 
 254   char* aligned_base = can_align_up(specified_base, alignment)
 255                            ? align_up(specified_base, alignment)
 256                            : nullptr;
 257 
 258   if (aligned_base != specified_base) {
 259     log_info(cds)("SharedBaseAddress (" INTPTR_FORMAT ") aligned up to " INTPTR_FORMAT,
 260                    p2i(specified_base), p2i(aligned_base));
 261   }
 262 
 263   const char* err = nullptr;
 264   if (aligned_base == nullptr) {
 265     err = "too high";
 266   } else if (shared_base_too_high(specified_base, aligned_base, cds_max)) {
 267     err = "too high";
 268   } else if (!shared_base_valid(aligned_base)) {
 269     err = "invalid for this platform";
 270   } else {
 271     return aligned_base;
 272   }
 273 
 274   // Arguments::default_SharedBaseAddress() is hard-coded in cds_globals.hpp. It must be carefully
 275   // picked that (a) the align_up() below will always return a valid value; (b) none of
 276   // the following asserts will fail.
 277   log_warning(cds)("SharedBaseAddress (" INTPTR_FORMAT ") is %s. Reverted to " INTPTR_FORMAT,
 278                    p2i((void*)SharedBaseAddress), err,
 279                    p2i((void*)Arguments::default_SharedBaseAddress()));
 280 
 281   specified_base = (char*)Arguments::default_SharedBaseAddress();
 282   aligned_base = align_up(specified_base, alignment);
 283 
 284   // Make sure the default value of SharedBaseAddress specified in globals.hpp is sane.
 285   assert(!shared_base_too_high(specified_base, aligned_base, cds_max), "Sanity");
 286   assert(shared_base_valid(aligned_base), "Sanity");
 287   return aligned_base;
 288 }
 289 
 290 void MetaspaceShared::initialize_for_static_dump() {
 291   assert(CDSConfig::is_dumping_static_archive(), "sanity");
 292   log_info(cds)("Core region alignment: %zu", core_region_alignment());
 293   // The max allowed size for CDS archive. We use this to limit SharedBaseAddress
 294   // to avoid address space wrap around.
 295   size_t cds_max;
 296   const size_t reserve_alignment = core_region_alignment();
 297 
 298 #ifdef _LP64
 299   const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
 300   cds_max = align_down(UnscaledClassSpaceMax, reserve_alignment);
 301 #else
 302   // We don't support archives larger than 256MB on 32-bit due to limited
 303   //  virtual address space.
 304   cds_max = align_down(256*M, reserve_alignment);
 305 #endif
 306 
 307   _requested_base_address = compute_shared_base(cds_max);
 308   SharedBaseAddress = (size_t)_requested_base_address;
 309 
 310   size_t symbol_rs_size = LP64_ONLY(3 * G) NOT_LP64(128 * M);
 311   _symbol_rs = MemoryReserver::reserve(symbol_rs_size,
 312                                        os::vm_allocation_granularity(),
 313                                        os::vm_page_size(),
 314                                        mtClassShared);
 315   if (!_symbol_rs.is_reserved()) {
 316     log_error(cds)("Unable to reserve memory for symbols: %zu bytes.", symbol_rs_size);
 317     MetaspaceShared::unrecoverable_writing_error();
 318   }
 319   _symbol_region.init(&_symbol_rs, &_symbol_vs);
 320 }
 321 
 322 // Called by universe_post_init()
 323 void MetaspaceShared::post_initialize(TRAPS) {
 324   if (CDSConfig::is_using_archive()) {
 325     int size = AOTClassLocationConfig::runtime()->length();
 326     if (size > 0) {
 327       CDSProtectionDomain::allocate_shared_data_arrays(size, CHECK);
 328     }
 329   }
 330 }
 331 
 332 // Extra java.lang.Strings to be added to the archive
 333 static GrowableArrayCHeap<OopHandle, mtClassShared>* _extra_interned_strings = nullptr;
 334 // Extra Symbols to be added to the archive
 335 static GrowableArrayCHeap<Symbol*, mtClassShared>* _extra_symbols = nullptr;
 336 // Methods managed by SystemDictionary::find_method_handle_intrinsic() to be added to the archive
 337 static GrowableArray<Method*>* _pending_method_handle_intrinsics = nullptr;
 338 
 339 void MetaspaceShared::read_extra_data(JavaThread* current, const char* filename) {
 340   _extra_interned_strings = new GrowableArrayCHeap<OopHandle, mtClassShared>(10000);
 341   _extra_symbols = new GrowableArrayCHeap<Symbol*, mtClassShared>(1000);
 342 
 343   HashtableTextDump reader(filename);
 344   reader.check_version("VERSION: 1.0");
 345 
 346   while (reader.remain() > 0) {
 347     int utf8_length;
 348     int prefix_type = reader.scan_prefix(&utf8_length);
 349     ResourceMark rm(current);
 350     if (utf8_length == 0x7fffffff) {
 351       // buf_len will overflown 32-bit value.
 352       log_error(cds)("string length too large: %d", utf8_length);
 353       MetaspaceShared::unrecoverable_loading_error();
 354     }
 355     int buf_len = utf8_length+1;
 356     char* utf8_buffer = NEW_RESOURCE_ARRAY(char, buf_len);
 357     reader.get_utf8(utf8_buffer, utf8_length);
 358     utf8_buffer[utf8_length] = '\0';
 359 
 360     if (prefix_type == HashtableTextDump::SymbolPrefix) {
 361       _extra_symbols->append(SymbolTable::new_permanent_symbol(utf8_buffer));
 362     } else{
 363       assert(prefix_type == HashtableTextDump::StringPrefix, "Sanity");
 364       ExceptionMark em(current);
 365       JavaThread* THREAD = current; // For exception macros.
 366       oop str = StringTable::intern(utf8_buffer, THREAD);
 367 
 368       if (HAS_PENDING_EXCEPTION) {
 369         log_warning(cds, heap)("[line %d] extra interned string allocation failed; size too large: %d",
 370                                reader.last_line_no(), utf8_length);
 371         CLEAR_PENDING_EXCEPTION;
 372       } else {
 373 #if INCLUDE_CDS_JAVA_HEAP
 374         if (ArchiveHeapWriter::is_string_too_large_to_archive(str)) {
 375           log_warning(cds, heap)("[line %d] extra interned string ignored; size too large: %d",
 376                                  reader.last_line_no(), utf8_length);
 377           continue;
 378         }
 379         // Make sure this string is included in the dumped interned string table.
 380         assert(str != nullptr, "must succeed");
 381         _extra_interned_strings->append(OopHandle(Universe::vm_global(), str));
 382 #endif
 383       }
 384     }
 385   }
 386 }
 387 
 388 void MetaspaceShared::make_method_handle_intrinsics_shareable() {
 389   for (int i = 0; i < _pending_method_handle_intrinsics->length(); i++) {
 390     Method* m = ArchiveBuilder::current()->get_buffered_addr(_pending_method_handle_intrinsics->at(i));
 391     m->remove_unshareable_info();
 392     // Each method has its own constant pool (which is distinct from m->method_holder()->constants());
 393     m->constants()->remove_unshareable_info();
 394   }
 395 }
 396 
 397 void MetaspaceShared::write_method_handle_intrinsics() {
 398   int len = _pending_method_handle_intrinsics->length();
 399   _archived_method_handle_intrinsics = ArchiveBuilder::new_ro_array<Method*>(len);
 400   int word_size = _archived_method_handle_intrinsics->size();
 401   for (int i = 0; i < len; i++) {
 402     Method* m = _pending_method_handle_intrinsics->at(i);
 403     ArchiveBuilder::current()->write_pointer_in_buffer(_archived_method_handle_intrinsics->adr_at(i), m);
 404     word_size += m->size() + m->constMethod()->size() + m->constants()->size();
 405     if (m->constants()->cache() != nullptr) {
 406       word_size += m->constants()->cache()->size();
 407     }
 408   }
 409   log_info(cds)("Archived %d method handle intrinsics (%d bytes)", len, word_size * BytesPerWord);
 410 }
 411 
 412 // About "serialize" --
 413 //
 414 // This is (probably a badly named) way to read/write a data stream of pointers and
 415 // miscellaneous data from/to the shared archive file. The usual code looks like this:
 416 //
 417 //     // These two global C++ variables are initialized during dump time.
 418 //     static int _archived_int;
 419 //     static MetaspaceObj* archived_ptr;
 420 //
 421 //     void MyClass::serialize(SerializeClosure* soc) {
 422 //         soc->do_int(&_archived_int);
 423 //         soc->do_int(&_archived_ptr);
 424 //     }
 425 //
 426 //     At dumptime, these two variables are stored into the CDS archive.
 427 //     At runtime, these two variables are loaded from the CDS archive.
 428 //     In addition, the pointer is relocated as necessary.
 429 //
 430 // Some of the xxx::serialize() functions may have side effects and assume that
 431 // the archive is already mapped. For example, SymbolTable::serialize_shared_table_header()
 432 // unconditionally makes the set of archived symbols available. Therefore, we put most
 433 // of these xxx::serialize() functions inside MetaspaceShared::serialize(), which
 434 // is called AFTER we made the decision to map the archive.
 435 //
 436 // However, some of the "serialized" data are used to decide whether an archive should
 437 // be mapped or not (e.g., for checking if the -Djdk.module.main property is compatible
 438 // with the archive). The xxx::serialize() functions for these data must be put inside
 439 // MetaspaceShared::early_serialize(). Such functions must not produce side effects that
 440 // assume we will always decides to map the archive.
 441 
 442 void MetaspaceShared::early_serialize(SerializeClosure* soc) {
 443   int tag = 0;
 444   soc->do_tag(--tag);
 445   CDS_JAVA_HEAP_ONLY(Modules::serialize_archived_module_info(soc);)
 446   soc->do_tag(666);
 447 }
 448 
 449 void MetaspaceShared::serialize(SerializeClosure* soc) {
 450   int tag = 0;
 451   soc->do_tag(--tag);
 452 
 453   // Verify the sizes of various metadata in the system.
 454   soc->do_tag(sizeof(Method));
 455   soc->do_tag(sizeof(ConstMethod));
 456   soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE));
 457   soc->do_tag(sizeof(ConstantPool));
 458   soc->do_tag(sizeof(ConstantPoolCache));
 459   soc->do_tag(objArrayOopDesc::base_offset_in_bytes());
 460   soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE));
 461   soc->do_tag(sizeof(Symbol));
 462 
 463   // Need to do this first, as subsequent steps may call virtual functions
 464   // in archived Metadata objects.
 465   CppVtables::serialize(soc);
 466   soc->do_tag(--tag);
 467 
 468   // Dump/restore miscellaneous metadata.
 469   JavaClasses::serialize_offsets(soc);
 470   Universe::serialize(soc);
 471   soc->do_tag(--tag);
 472 
 473   // Dump/restore references to commonly used names and signatures.
 474   vmSymbols::serialize(soc);
 475   soc->do_tag(--tag);
 476 
 477   // Dump/restore the symbol/string/subgraph_info tables
 478   SymbolTable::serialize_shared_table_header(soc);
 479   StringTable::serialize_shared_table_header(soc);
 480   HeapShared::serialize_tables(soc);
 481   SystemDictionaryShared::serialize_dictionary_headers(soc);
 482   AOTLinkedClassBulkLoader::serialize(soc, true);
 483   FinalImageRecipes::serialize(soc);
 484   InstanceMirrorKlass::serialize_offsets(soc);
 485 
 486   // Dump/restore well known classes (pointers)
 487   SystemDictionaryShared::serialize_vm_classes(soc);
 488   soc->do_tag(--tag);
 489 
 490   CDS_JAVA_HEAP_ONLY(ClassLoaderDataShared::serialize(soc);)
 491   soc->do_ptr((void**)&_archived_method_handle_intrinsics);
 492 
 493   LambdaFormInvokers::serialize(soc);
 494   soc->do_tag(666);
 495 }
 496 
 497 static void rewrite_nofast_bytecode(const methodHandle& method) {
 498   BytecodeStream bcs(method);
 499   while (!bcs.is_last_bytecode()) {
 500     Bytecodes::Code opcode = bcs.next();
 501     switch (opcode) {
 502     case Bytecodes::_getfield:      *bcs.bcp() = Bytecodes::_nofast_getfield;      break;
 503     case Bytecodes::_putfield:      *bcs.bcp() = Bytecodes::_nofast_putfield;      break;
 504     case Bytecodes::_aload_0:       *bcs.bcp() = Bytecodes::_nofast_aload_0;       break;
 505     case Bytecodes::_iload: {
 506       if (!bcs.is_wide()) {
 507         *bcs.bcp() = Bytecodes::_nofast_iload;
 508       }
 509       break;
 510     }
 511     default: break;
 512     }
 513   }
 514 }
 515 
 516 // [1] Rewrite all bytecodes as needed, so that the ConstMethod* will not be modified
 517 //     at run time by RewriteBytecodes/RewriteFrequentPairs
 518 // [2] Assign a fingerprint, so one doesn't need to be assigned at run-time.
 519 void MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread* thread, InstanceKlass* ik) {
 520   for (int i = 0; i < ik->methods()->length(); i++) {
 521     methodHandle m(thread, ik->methods()->at(i));
 522     if (ik->can_be_verified_at_dumptime() && ik->is_linked()) {
 523       rewrite_nofast_bytecode(m);
 524     }
 525     Fingerprinter fp(m);
 526     // The side effect of this call sets method's fingerprint field.
 527     fp.fingerprint();
 528   }
 529 }
 530 
 531 class VM_PopulateDumpSharedSpace : public VM_Operation {
 532 private:
 533   ArchiveHeapInfo _heap_info;
 534   FileMapInfo* _map_info;
 535   StaticArchiveBuilder& _builder;
 536 
 537   void dump_java_heap_objects();
 538   void dump_shared_symbol_table(GrowableArray<Symbol*>* symbols) {
 539     log_info(cds)("Dumping symbol table ...");
 540     SymbolTable::write_to_archive(symbols);
 541   }
 542   char* dump_early_read_only_tables();
 543   char* dump_read_only_tables(AOTClassLocationConfig*& cl_config);
 544 
 545 public:
 546 
 547   VM_PopulateDumpSharedSpace(StaticArchiveBuilder& b) :
 548     VM_Operation(), _heap_info(), _map_info(nullptr), _builder(b) {}
 549 
 550   bool skip_operation() const { return false; }
 551 
 552   VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
 553   ArchiveHeapInfo* heap_info()  { return &_heap_info; }
 554   FileMapInfo* map_info() const { return _map_info; }
 555   void doit();   // outline because gdb sucks
 556   bool allow_nested_vm_operations() const { return true; }
 557 }; // class VM_PopulateDumpSharedSpace
 558 
 559 class StaticArchiveBuilder : public ArchiveBuilder {
 560 public:
 561   StaticArchiveBuilder() : ArchiveBuilder() {}
 562 
 563   virtual void iterate_roots(MetaspaceClosure* it) {
 564     AOTArtifactFinder::all_cached_classes_do(it);
 565     SystemDictionaryShared::dumptime_classes_do(it);
 566     Universe::metaspace_pointers_do(it);
 567     vmSymbols::metaspace_pointers_do(it);
 568 
 569     // The above code should find all the symbols that are referenced by the
 570     // archived classes. We just need to add the extra symbols which
 571     // may not be used by any of the archived classes -- these are usually
 572     // symbols that we anticipate to be used at run time, so we can store
 573     // them in the RO region, to be shared across multiple processes.
 574     if (_extra_symbols != nullptr) {
 575       for (int i = 0; i < _extra_symbols->length(); i++) {
 576         it->push(_extra_symbols->adr_at(i));
 577       }
 578     }
 579 
 580     for (int i = 0; i < _pending_method_handle_intrinsics->length(); i++) {
 581       it->push(_pending_method_handle_intrinsics->adr_at(i));
 582     }
 583   }
 584 };
 585 
 586 char* VM_PopulateDumpSharedSpace::dump_early_read_only_tables() {
 587   ArchiveBuilder::OtherROAllocMark mark;
 588 
 589   CDS_JAVA_HEAP_ONLY(Modules::dump_archived_module_info());
 590 
 591   DumpRegion* ro_region = ArchiveBuilder::current()->ro_region();
 592   char* start = ro_region->top();
 593   WriteClosure wc(ro_region);
 594   MetaspaceShared::early_serialize(&wc);
 595   return start;
 596 }
 597 
 598 char* VM_PopulateDumpSharedSpace::dump_read_only_tables(AOTClassLocationConfig*& cl_config) {
 599   ArchiveBuilder::OtherROAllocMark mark;
 600 
 601   SystemDictionaryShared::write_to_archive();
 602   cl_config = AOTClassLocationConfig::dumptime()->write_to_archive();
 603   AOTClassLinker::write_to_archive();
 604   if (CDSConfig::is_dumping_preimage_static_archive()) {
 605     FinalImageRecipes::record_recipes();
 606   }
 607   MetaspaceShared::write_method_handle_intrinsics();
 608 
 609   // Write lambform lines into archive
 610   LambdaFormInvokers::dump_static_archive_invokers();
 611 
 612   // Write the other data to the output array.
 613   DumpRegion* ro_region = ArchiveBuilder::current()->ro_region();
 614   char* start = ro_region->top();
 615   WriteClosure wc(ro_region);
 616   MetaspaceShared::serialize(&wc);
 617 
 618   return start;
 619 }
 620 
 621 void VM_PopulateDumpSharedSpace::doit() {
 622   if (!CDSConfig::is_dumping_final_static_archive()) {
 623     guarantee(!CDSConfig::is_using_archive(), "We should not be using an archive when we dump");
 624   }
 625 
 626   DEBUG_ONLY(SystemDictionaryShared::NoClassLoadingMark nclm);
 627 
 628   _pending_method_handle_intrinsics = new (mtClassShared) GrowableArray<Method*>(256, mtClassShared);
 629   if (CDSConfig::is_dumping_method_handles()) {
 630     // When dumping AOT-linked classes, some classes may have direct references to a method handle
 631     // intrinsic. The easiest thing is to save all of them into the AOT cache.
 632     SystemDictionary::get_all_method_handle_intrinsics(_pending_method_handle_intrinsics);
 633   }
 634 
 635   AOTClassLocationConfig::dumptime_check_nonempty_dirs();
 636 
 637   NOT_PRODUCT(SystemDictionary::verify();)
 638 
 639   // Block concurrent class unloading from changing the _dumptime_table
 640   MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
 641 
 642 #if INCLUDE_CDS_JAVA_HEAP
 643   if (CDSConfig::is_dumping_heap() && _extra_interned_strings != nullptr) {
 644     for (int i = 0; i < _extra_interned_strings->length(); i ++) {
 645       OopHandle string = _extra_interned_strings->at(i);
 646       HeapShared::add_to_dumped_interned_strings(string.resolve());
 647     }
 648   }
 649 #endif
 650 
 651   _builder.gather_source_objs();
 652   _builder.reserve_buffer();
 653 
 654   CppVtables::dumptime_init(&_builder);
 655 
 656   _builder.sort_metadata_objs();
 657   _builder.dump_rw_metadata();
 658   _builder.dump_ro_metadata();
 659   _builder.relocate_metaspaceobj_embedded_pointers();
 660 
 661   log_info(cds)("Make classes shareable");
 662   _builder.make_klasses_shareable();
 663   MetaspaceShared::make_method_handle_intrinsics_shareable();
 664 
 665   dump_java_heap_objects();
 666   dump_shared_symbol_table(_builder.symbols());
 667 
 668   char* early_serialized_data = dump_early_read_only_tables();
 669   AOTClassLocationConfig* cl_config;
 670   char* serialized_data = dump_read_only_tables(cl_config);
 671 
 672   if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
 673     log_info(cds)("Adjust lambda proxy class dictionary");
 674     LambdaProxyClassDictionary::adjust_dumptime_table();
 675   }
 676 
 677   // The vtable clones contain addresses of the current process.
 678   // We don't want to write these addresses into the archive.
 679   CppVtables::zero_archived_vtables();
 680 
 681   // Write the archive file
 682   if (CDSConfig::is_dumping_final_static_archive()) {
 683     FileMapInfo::free_current_info(); // FIXME: should not free current info
 684   }
 685   const char* static_archive = CDSConfig::output_archive_path();
 686   assert(static_archive != nullptr, "sanity");
 687   _map_info = new FileMapInfo(static_archive, true);
 688   _map_info->populate_header(MetaspaceShared::core_region_alignment());
 689   _map_info->set_early_serialized_data(early_serialized_data);
 690   _map_info->set_serialized_data(serialized_data);
 691   _map_info->set_cloned_vtables(CppVtables::vtables_serialized_base());
 692   _map_info->header()->set_class_location_config(cl_config);
 693 }
 694 
 695 class CollectClassesForLinking : public KlassClosure {
 696   GrowableArray<OopHandle> _mirrors;
 697 
 698 public:
 699    CollectClassesForLinking() : _mirrors() {
 700      // ClassLoaderDataGraph::loaded_classes_do_keepalive() requires ClassLoaderDataGraph_lock.
 701      // We cannot link the classes while holding this lock (or else we may run into deadlock).
 702      // Therefore, we need to first collect all the classes, keeping them alive by
 703      // holding onto their java_mirrors in global OopHandles. We then link the classes after
 704      // releasing the lock.
 705      MutexLocker lock(ClassLoaderDataGraph_lock);
 706      ClassLoaderDataGraph::loaded_classes_do_keepalive(this);
 707    }
 708 
 709   ~CollectClassesForLinking() {
 710     for (int i = 0; i < _mirrors.length(); i++) {
 711       _mirrors.at(i).release(Universe::vm_global());
 712     }
 713   }
 714 
 715   void do_cld(ClassLoaderData* cld) {
 716     assert(cld->is_alive(), "must be");
 717   }
 718 
 719   void do_klass(Klass* k) {
 720     if (k->is_instance_klass()) {
 721       _mirrors.append(OopHandle(Universe::vm_global(), k->java_mirror()));
 722     }
 723   }
 724 
 725   const GrowableArray<OopHandle>* mirrors() const { return &_mirrors; }
 726 };
 727 
 728 // Check if we can eagerly link this class at dump time, so we can avoid the
 729 // runtime linking overhead (especially verification)
 730 bool MetaspaceShared::may_be_eagerly_linked(InstanceKlass* ik) {
 731   if (!ik->can_be_verified_at_dumptime()) {
 732     // For old classes, try to leave them in the unlinked state, so
 733     // we can still store them in the archive. They must be
 734     // linked/verified at runtime.
 735     return false;
 736   }
 737   if (CDSConfig::is_dumping_dynamic_archive() && ik->is_shared_unregistered_class()) {
 738     // Linking of unregistered classes at this stage may cause more
 739     // classes to be resolved, resulting in calls to ClassLoader.loadClass()
 740     // that may not be expected by custom class loaders.
 741     //
 742     // It's OK to do this for the built-in loaders as we know they can
 743     // tolerate this.
 744     return false;
 745   }
 746   return true;
 747 }
 748 
 749 void MetaspaceShared::link_shared_classes(TRAPS) {
 750   AOTClassLinker::initialize();
 751   AOTClassInitializer::init_test_class(CHECK);
 752 
 753   while (true) {
 754     ResourceMark rm(THREAD);
 755     CollectClassesForLinking collect_classes;
 756     bool has_linked = false;
 757     const GrowableArray<OopHandle>* mirrors = collect_classes.mirrors();
 758     for (int i = 0; i < mirrors->length(); i++) {
 759       OopHandle mirror = mirrors->at(i);
 760       InstanceKlass* ik = InstanceKlass::cast(java_lang_Class::as_Klass(mirror.resolve()));
 761       if (may_be_eagerly_linked(ik)) {
 762         has_linked |= try_link_class(THREAD, ik);
 763       }
 764     }
 765 
 766     if (!has_linked) {
 767       break;
 768     }
 769     // Class linking includes verification which may load more classes.
 770     // Keep scanning until we have linked no more classes.
 771   }
 772 
 773   // Resolve constant pool entries -- we don't load any new classes during this stage
 774   {
 775     ResourceMark rm(THREAD);
 776     CollectClassesForLinking collect_classes;
 777     const GrowableArray<OopHandle>* mirrors = collect_classes.mirrors();
 778     for (int i = 0; i < mirrors->length(); i++) {
 779       OopHandle mirror = mirrors->at(i);
 780       InstanceKlass* ik = InstanceKlass::cast(java_lang_Class::as_Klass(mirror.resolve()));
 781       AOTConstantPoolResolver::dumptime_resolve_constants(ik, CHECK);
 782     }
 783   }
 784 
 785   if (CDSConfig::is_dumping_final_static_archive()) {
 786     FinalImageRecipes::apply_recipes(CHECK);
 787   }
 788 }
 789 
 790 // Preload classes from a list, populate the shared spaces and dump to a
 791 // file.
 792 void MetaspaceShared::preload_and_dump(TRAPS) {
 793   CDSConfig::DumperThreadMark dumper_thread_mark(THREAD);
 794   ResourceMark rm(THREAD);
 795   StaticArchiveBuilder builder;
 796   preload_and_dump_impl(builder, THREAD);
 797   if (HAS_PENDING_EXCEPTION) {
 798     if (PENDING_EXCEPTION->is_a(vmClasses::OutOfMemoryError_klass())) {
 799       log_error(cds)("Out of memory. Please run with a larger Java heap, current MaxHeapSize = "
 800                      "%zuM", MaxHeapSize/M);
 801       MetaspaceShared::writing_error();
 802     } else {
 803       log_error(cds)("%s: %s", PENDING_EXCEPTION->klass()->external_name(),
 804                      java_lang_String::as_utf8_string(java_lang_Throwable::message(PENDING_EXCEPTION)));
 805       MetaspaceShared::writing_error("Unexpected exception, use -Xlog:cds,exceptions=trace for detail");
 806     }
 807   }
 808 
 809   if (CDSConfig::new_aot_flags_used()) {
 810     if (CDSConfig::is_dumping_preimage_static_archive()) {
 811       // We are in the JVM that runs the training run. Continue execution,
 812       // so that it can finish all clean-up and return the correct exit
 813       // code to the OS.
 814       tty->print_cr("AOTConfiguration recorded: %s", AOTConfiguration);
 815     } else {
 816       // The JLI launcher only recognizes the "old" -Xshare:dump flag.
 817       // When the new -XX:AOTMode=create flag is used, we can't return
 818       // to the JLI launcher, as the launcher will fail when trying to
 819       // run the main class, which is not what we want.
 820       struct stat st;
 821       if (os::stat(AOTCache, &st) != 0) {
 822         tty->print_cr("AOTCache creation failed: %s", AOTCache);
 823         vm_exit(0);
 824       } else {
 825         tty->print_cr("AOTCache creation is complete: %s " INT64_FORMAT " bytes", AOTCache, (int64_t)(st.st_size));
 826         vm_exit(0);
 827       }
 828     }
 829   }
 830 }
 831 
 832 #if INCLUDE_CDS_JAVA_HEAP && defined(_LP64)
 833 void MetaspaceShared::adjust_heap_sizes_for_dumping() {
 834   if (!CDSConfig::is_dumping_heap() || UseCompressedOops) {
 835     return;
 836   }
 837   // CDS heap dumping requires all string oops to have an offset
 838   // from the heap bottom that can be encoded in 32-bit.
 839   julong max_heap_size = (julong)(4 * G);
 840 
 841   if (MinHeapSize > max_heap_size) {
 842     log_debug(cds)("Setting MinHeapSize to 4G for CDS dumping, original size = %zuM", MinHeapSize/M);
 843     FLAG_SET_ERGO(MinHeapSize, max_heap_size);
 844   }
 845   if (InitialHeapSize > max_heap_size) {
 846     log_debug(cds)("Setting InitialHeapSize to 4G for CDS dumping, original size = %zuM", InitialHeapSize/M);
 847     FLAG_SET_ERGO(InitialHeapSize, max_heap_size);
 848   }
 849   if (MaxHeapSize > max_heap_size) {
 850     log_debug(cds)("Setting MaxHeapSize to 4G for CDS dumping, original size = %zuM", MaxHeapSize/M);
 851     FLAG_SET_ERGO(MaxHeapSize, max_heap_size);
 852   }
 853 }
 854 #endif // INCLUDE_CDS_JAVA_HEAP && _LP64
 855 
 856 void MetaspaceShared::get_default_classlist(char* default_classlist, const size_t buf_size) {
 857   const char* filesep = os::file_separator();
 858   jio_snprintf(default_classlist, buf_size, "%s%slib%sclasslist",
 859                Arguments::get_java_home(), filesep, filesep);
 860 }
 861 
 862 void MetaspaceShared::preload_classes(TRAPS) {
 863   char default_classlist[JVM_MAXPATHLEN];
 864   const char* classlist_path;
 865 
 866   get_default_classlist(default_classlist, JVM_MAXPATHLEN);
 867   if (SharedClassListFile == nullptr) {
 868     classlist_path = default_classlist;
 869   } else {
 870     classlist_path = SharedClassListFile;
 871   }
 872 
 873   log_info(cds)("Loading classes to share ...");
 874   ClassListParser::parse_classlist(classlist_path,
 875                                    ClassListParser::_parse_all, CHECK);
 876   if (ExtraSharedClassListFile) {
 877     ClassListParser::parse_classlist(ExtraSharedClassListFile,
 878                                      ClassListParser::_parse_all, CHECK);
 879   }
 880   if (classlist_path != default_classlist) {
 881     struct stat statbuf;
 882     if (os::stat(default_classlist, &statbuf) == 0) {
 883       // File exists, let's use it.
 884       ClassListParser::parse_classlist(default_classlist,
 885                                        ClassListParser::_parse_lambda_forms_invokers_only, CHECK);
 886     }
 887   }
 888 
 889   // Some classes are used at CDS runtime but are not loaded, and therefore archived, at
 890   // dumptime. We can perform dummmy calls to these classes at dumptime to ensure they
 891   // are archived.
 892   exercise_runtime_cds_code(CHECK);
 893 
 894   log_info(cds)("Loading classes to share: done.");
 895 }
 896 
 897 void MetaspaceShared::exercise_runtime_cds_code(TRAPS) {
 898   // Exercise the manifest processing code
 899   const char* dummy = "Manifest-Version: 1.0\n";
 900   CDSProtectionDomain::create_jar_manifest(dummy, strlen(dummy), CHECK);
 901 
 902   // Exercise FileSystem and URL code
 903   CDSProtectionDomain::to_file_URL("dummy.jar", Handle(), CHECK);
 904 }
 905 
 906 void MetaspaceShared::preload_and_dump_impl(StaticArchiveBuilder& builder, TRAPS) {
 907   if (CDSConfig::is_dumping_classic_static_archive()) {
 908     // We are running with -Xshare:dump
 909     preload_classes(CHECK);
 910 
 911     if (SharedArchiveConfigFile) {
 912       log_info(cds)("Reading extra data from %s ...", SharedArchiveConfigFile);
 913       read_extra_data(THREAD, SharedArchiveConfigFile);
 914       log_info(cds)("Reading extra data: done.");
 915     }
 916   }
 917 
 918   if (CDSConfig::is_dumping_preimage_static_archive()) {
 919     log_info(cds)("Reading lambda form invokers from JDK default classlist ...");
 920     char default_classlist[JVM_MAXPATHLEN];
 921     get_default_classlist(default_classlist, JVM_MAXPATHLEN);
 922     struct stat statbuf;
 923     if (os::stat(default_classlist, &statbuf) == 0) {
 924       ClassListParser::parse_classlist(default_classlist,
 925                                        ClassListParser::_parse_lambda_forms_invokers_only, CHECK);
 926     }
 927   }
 928 
 929 #if INCLUDE_CDS_JAVA_HEAP
 930   if (CDSConfig::is_dumping_heap()) {
 931     assert(CDSConfig::allow_only_single_java_thread(), "Required");
 932     if (!HeapShared::is_archived_boot_layer_available(THREAD)) {
 933       log_info(cds)("archivedBootLayer not available, disabling full module graph");
 934       CDSConfig::stop_dumping_full_module_graph();
 935     }
 936     // Do this before link_shared_classes(), as the following line may load new classes.
 937     HeapShared::init_for_dumping(CHECK);
 938   }
 939 #endif
 940 
 941   if (CDSConfig::is_dumping_final_static_archive()) {
 942     if (ExtraSharedClassListFile) {
 943       log_info(cds)("Loading extra classes from %s ...", ExtraSharedClassListFile);
 944       ClassListParser::parse_classlist(ExtraSharedClassListFile,
 945                                        ClassListParser::_parse_all, CHECK);
 946     }
 947   }
 948 
 949   // Rewrite and link classes
 950   log_info(cds)("Rewriting and linking classes ...");
 951 
 952   // Link any classes which got missed. This would happen if we have loaded classes that
 953   // were not explicitly specified in the classlist. E.g., if an interface implemented by class K
 954   // fails verification, all other interfaces that were not specified in the classlist but
 955   // are implemented by K are not verified.
 956   link_shared_classes(CHECK);
 957   log_info(cds)("Rewriting and linking classes: done");
 958 
 959   if (CDSConfig::is_dumping_regenerated_lambdaform_invokers()) {
 960     LambdaFormInvokers::regenerate_holder_classes(CHECK);
 961   }
 962 
 963 #if INCLUDE_CDS_JAVA_HEAP
 964   if (CDSConfig::is_dumping_heap()) {
 965     ArchiveHeapWriter::init();
 966 
 967     if (CDSConfig::is_dumping_full_module_graph()) {
 968       ClassLoaderDataShared::ensure_module_entry_tables_exist();
 969       HeapShared::reset_archived_object_states(CHECK);
 970     }
 971 
 972     AOTReferenceObjSupport::initialize(CHECK);
 973     AOTReferenceObjSupport::stabilize_cached_reference_objects(CHECK);
 974 
 975     if (CDSConfig::is_initing_classes_at_dump_time()) {
 976       // java.lang.Class::reflectionFactory cannot be archived yet. We set this field
 977       // to null, and it will be initialized again at runtime.
 978       log_debug(cds)("Resetting Class::reflectionFactory");
 979       TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
 980       Symbol* method_sig = vmSymbols::void_method_signature();
 981       JavaValue result(T_VOID);
 982       JavaCalls::call_static(&result, vmClasses::Class_klass(),
 983                              method_name, method_sig, CHECK);
 984 
 985       // Perhaps there is a way to avoid hard-coding these names here.
 986       // See discussion in JDK-8342481.
 987     }
 988 
 989     // Do this at the very end, when no Java code will be executed. Otherwise
 990     // some new strings may be added to the intern table.
 991     StringTable::allocate_shared_strings_array(CHECK);
 992   } else {
 993     log_info(cds)("Not dumping heap, reset CDSConfig::_is_using_optimized_module_handling");
 994     CDSConfig::stop_using_optimized_module_handling();
 995   }
 996 #endif
 997 
 998   VM_PopulateDumpSharedSpace op(builder);
 999   VMThread::execute(&op);
1000 
1001   if (!write_static_archive(&builder, op.map_info(), op.heap_info())) {
1002     THROW_MSG(vmSymbols::java_io_IOException(), "Encountered error while dumping");
1003   }
1004 }
1005 
1006 bool MetaspaceShared::write_static_archive(ArchiveBuilder* builder, FileMapInfo* map_info, ArchiveHeapInfo* heap_info) {
1007   // relocate the data so that it can be mapped to MetaspaceShared::requested_base_address()
1008   // without runtime relocation.
1009   builder->relocate_to_requested();
1010 
1011   map_info->open_as_output();
1012   if (!map_info->is_open()) {
1013     return false;
1014   }
1015   builder->write_archive(map_info, heap_info);
1016 
1017   if (AllowArchivingWithJavaAgent) {
1018     log_warning(cds)("This %s was created with AllowArchivingWithJavaAgent. It should be used "
1019             "for testing purposes only and should not be used in a production environment", CDSConfig::type_of_archive_being_loaded());
1020   }
1021   return true;
1022 }
1023 
1024 // Returns true if the class's status has changed.
1025 bool MetaspaceShared::try_link_class(JavaThread* current, InstanceKlass* ik) {
1026   ExceptionMark em(current);
1027   JavaThread* THREAD = current; // For exception macros.
1028   assert(CDSConfig::is_dumping_archive(), "sanity");
1029 
1030   if (ik->is_shared() && !CDSConfig::is_dumping_final_static_archive()) {
1031     assert(CDSConfig::is_dumping_dynamic_archive(), "must be");
1032     return false;
1033   }
1034 
1035   if (ik->is_loaded() && !ik->is_linked() && ik->can_be_verified_at_dumptime() &&
1036       !SystemDictionaryShared::has_class_failed_verification(ik)) {
1037     bool saved = BytecodeVerificationLocal;
1038     if (ik->is_shared_unregistered_class() && ik->class_loader() == nullptr) {
1039       // The verification decision is based on BytecodeVerificationRemote
1040       // for non-system classes. Since we are using the null classloader
1041       // to load non-system classes for customized class loaders during dumping,
1042       // we need to temporarily change BytecodeVerificationLocal to be the same as
1043       // BytecodeVerificationRemote. Note this can cause the parent system
1044       // classes also being verified. The extra overhead is acceptable during
1045       // dumping.
1046       BytecodeVerificationLocal = BytecodeVerificationRemote;
1047     }
1048     ik->link_class(THREAD);
1049     if (HAS_PENDING_EXCEPTION) {
1050       ResourceMark rm(THREAD);
1051       log_warning(cds)("Preload Warning: Verification failed for %s",
1052                     ik->external_name());
1053       CLEAR_PENDING_EXCEPTION;
1054       SystemDictionaryShared::set_class_has_failed_verification(ik);
1055     } else {
1056       assert(!SystemDictionaryShared::has_class_failed_verification(ik), "sanity");
1057       ik->compute_has_loops_flag_for_methods();
1058     }
1059     BytecodeVerificationLocal = saved;
1060     return true;
1061   } else {
1062     return false;
1063   }
1064 }
1065 
1066 void VM_PopulateDumpSharedSpace::dump_java_heap_objects() {
1067   if (CDSConfig::is_dumping_heap()) {
1068     HeapShared::write_heap(&_heap_info);
1069   } else {
1070     CDSConfig::log_reasons_for_not_dumping_heap();
1071   }
1072 }
1073 
1074 void MetaspaceShared::set_shared_metaspace_range(void* base, void *static_top, void* top) {
1075   assert(base <= static_top && static_top <= top, "must be");
1076   _shared_metaspace_static_top = static_top;
1077   MetaspaceObj::set_shared_metaspace_range(base, top);
1078 }
1079 
1080 bool MetaspaceShared::is_shared_dynamic(void* p) {
1081   if ((p < MetaspaceObj::shared_metaspace_top()) &&
1082       (p >= _shared_metaspace_static_top)) {
1083     return true;
1084   } else {
1085     return false;
1086   }
1087 }
1088 
1089 bool MetaspaceShared::is_shared_static(void* p) {
1090   if (is_in_shared_metaspace(p) && !is_shared_dynamic(p)) {
1091     return true;
1092   } else {
1093     return false;
1094   }
1095 }
1096 
1097 // This function is called when the JVM is unable to load the specified archive(s) due to one
1098 // of the following conditions.
1099 // - There's an error that indicates that the archive(s) files were corrupt or otherwise damaged.
1100 // - When -XX:+RequireSharedSpaces is specified, AND the JVM cannot load the archive(s) due
1101 //   to version or classpath mismatch.
1102 void MetaspaceShared::unrecoverable_loading_error(const char* message) {
1103   log_error(cds)("An error has occurred while processing the %s.", CDSConfig::type_of_archive_being_loaded());
1104   if (message != nullptr) {
1105     log_error(cds)("%s", message);
1106   }
1107 
1108   if (CDSConfig::is_dumping_final_static_archive()) {
1109     vm_exit_during_initialization("Must be a valid AOT configuration generated by the current JVM", AOTConfiguration);
1110   } else if (CDSConfig::new_aot_flags_used()) {
1111     vm_exit_during_initialization("Unable to use AOT cache.", nullptr);
1112   } else {
1113     vm_exit_during_initialization("Unable to use shared archive.", nullptr);
1114   }
1115 }
1116 
1117 // This function is called when the JVM is unable to write the specified CDS archive due to an
1118 // unrecoverable error.
1119 void MetaspaceShared::unrecoverable_writing_error(const char* message) {
1120   writing_error(message);
1121   vm_direct_exit(1);
1122 }
1123 
1124 // This function is called when the JVM is unable to write the specified CDS archive due to a
1125 // an error. The error will be propagated
1126 void MetaspaceShared::writing_error(const char* message) {
1127   log_error(cds)("An error has occurred while writing the shared archive file.");
1128   if (message != nullptr) {
1129     log_error(cds)("%s", message);
1130   }
1131 }
1132 
1133 void MetaspaceShared::initialize_runtime_shared_and_meta_spaces() {
1134   assert(CDSConfig::is_using_archive(), "Must be called when UseSharedSpaces is enabled");
1135   MapArchiveResult result = MAP_ARCHIVE_OTHER_FAILURE;
1136 
1137   FileMapInfo* static_mapinfo = open_static_archive();
1138   FileMapInfo* dynamic_mapinfo = nullptr;
1139 
1140   if (static_mapinfo != nullptr) {
1141     log_info(cds)("Core region alignment: %zu", static_mapinfo->core_region_alignment());
1142     dynamic_mapinfo = open_dynamic_archive();
1143 
1144     log_info(cds)("ArchiveRelocationMode: %d", ArchiveRelocationMode);
1145 
1146     // First try to map at the requested address
1147     result = map_archives(static_mapinfo, dynamic_mapinfo, true);
1148     if (result == MAP_ARCHIVE_MMAP_FAILURE) {
1149       // Mapping has failed (probably due to ASLR). Let's map at an address chosen
1150       // by the OS.
1151       log_info(cds)("Try to map archive(s) at an alternative address");
1152       result = map_archives(static_mapinfo, dynamic_mapinfo, false);
1153     }
1154   }
1155 
1156   if (result == MAP_ARCHIVE_SUCCESS) {
1157     bool dynamic_mapped = (dynamic_mapinfo != nullptr && dynamic_mapinfo->is_mapped());
1158     char* cds_base = static_mapinfo->mapped_base();
1159     char* cds_end =  dynamic_mapped ? dynamic_mapinfo->mapped_end() : static_mapinfo->mapped_end();
1160     // Register CDS memory region with LSan.
1161     LSAN_REGISTER_ROOT_REGION(cds_base, cds_end - cds_base);
1162     set_shared_metaspace_range(cds_base, static_mapinfo->mapped_end(), cds_end);
1163     _relocation_delta = static_mapinfo->relocation_delta();
1164     _requested_base_address = static_mapinfo->requested_base_address();
1165     if (dynamic_mapped) {
1166       // turn AutoCreateSharedArchive off if successfully mapped
1167       AutoCreateSharedArchive = false;
1168     }
1169   } else {
1170     set_shared_metaspace_range(nullptr, nullptr, nullptr);
1171     if (CDSConfig::is_dumping_dynamic_archive()) {
1172       log_warning(cds)("-XX:ArchiveClassesAtExit is unsupported when base CDS archive is not loaded. Run with -Xlog:cds for more info.");
1173     }
1174     UseSharedSpaces = false;
1175     // The base archive cannot be mapped. We cannot dump the dynamic shared archive.
1176     AutoCreateSharedArchive = false;
1177     CDSConfig::disable_dumping_dynamic_archive();
1178     log_info(cds)("Unable to map shared spaces");
1179     if (PrintSharedArchiveAndExit) {
1180       MetaspaceShared::unrecoverable_loading_error("Unable to use shared archive.");
1181     } else if (RequireSharedSpaces) {
1182       MetaspaceShared::unrecoverable_loading_error("Unable to map shared spaces");
1183     }
1184   }
1185 
1186   // If mapping failed and -XShare:on, the vm should exit
1187   bool has_failed = false;
1188   if (static_mapinfo != nullptr && !static_mapinfo->is_mapped()) {
1189     has_failed = true;
1190     delete static_mapinfo;
1191   }
1192   if (dynamic_mapinfo != nullptr && !dynamic_mapinfo->is_mapped()) {
1193     has_failed = true;
1194     delete dynamic_mapinfo;
1195   }
1196   if (RequireSharedSpaces && has_failed) {
1197       MetaspaceShared::unrecoverable_loading_error("Unable to map shared spaces");
1198   }
1199 }
1200 
1201 FileMapInfo* MetaspaceShared::open_static_archive() {
1202   const char* static_archive = CDSConfig::input_static_archive_path();
1203   assert(static_archive != nullptr, "sanity");
1204   FileMapInfo* mapinfo = new FileMapInfo(static_archive, true);
1205   if (!mapinfo->open_as_input()) {
1206     delete(mapinfo);
1207     return nullptr;
1208   }
1209   return mapinfo;
1210 }
1211 
1212 FileMapInfo* MetaspaceShared::open_dynamic_archive() {
1213   if (CDSConfig::is_dumping_dynamic_archive()) {
1214     return nullptr;
1215   }
1216   const char* dynamic_archive = CDSConfig::input_dynamic_archive_path();
1217   if (dynamic_archive == nullptr) {
1218     return nullptr;
1219   }
1220 
1221   FileMapInfo* mapinfo = new FileMapInfo(dynamic_archive, false);
1222   if (!mapinfo->open_as_input()) {
1223     delete(mapinfo);
1224     if (RequireSharedSpaces) {
1225       MetaspaceShared::unrecoverable_loading_error("Failed to initialize dynamic archive");
1226     }
1227     return nullptr;
1228   }
1229   return mapinfo;
1230 }
1231 
1232 // use_requested_addr:
1233 //  true  = map at FileMapHeader::_requested_base_address
1234 //  false = map at an alternative address picked by OS.
1235 MapArchiveResult MetaspaceShared::map_archives(FileMapInfo* static_mapinfo, FileMapInfo* dynamic_mapinfo,
1236                                                bool use_requested_addr) {
1237   if (use_requested_addr && static_mapinfo->requested_base_address() == nullptr) {
1238     log_info(cds)("Archive(s) were created with -XX:SharedBaseAddress=0. Always map at os-selected address.");
1239     return MAP_ARCHIVE_MMAP_FAILURE;
1240   }
1241 
1242   PRODUCT_ONLY(if (ArchiveRelocationMode == 1 && use_requested_addr) {
1243       // For product build only -- this is for benchmarking the cost of doing relocation.
1244       // For debug builds, the check is done below, after reserving the space, for better test coverage
1245       // (see comment below).
1246       log_info(cds)("ArchiveRelocationMode == 1: always map archive(s) at an alternative address");
1247       return MAP_ARCHIVE_MMAP_FAILURE;
1248     });
1249 
1250   if (ArchiveRelocationMode == 2 && !use_requested_addr) {
1251     log_info(cds)("ArchiveRelocationMode == 2: never map archive(s) at an alternative address");
1252     return MAP_ARCHIVE_MMAP_FAILURE;
1253   };
1254 
1255   if (dynamic_mapinfo != nullptr) {
1256     // Ensure that the OS won't be able to allocate new memory spaces between the two
1257     // archives, or else it would mess up the simple comparison in MetaspaceObj::is_shared().
1258     assert(static_mapinfo->mapping_end_offset() == dynamic_mapinfo->mapping_base_offset(), "no gap");
1259   }
1260 
1261   ReservedSpace total_space_rs, archive_space_rs, class_space_rs;
1262   MapArchiveResult result = MAP_ARCHIVE_OTHER_FAILURE;
1263   size_t prot_zone_size = 0;
1264   char* mapped_base_address = reserve_address_space_for_archives(static_mapinfo,
1265                                                                  dynamic_mapinfo,
1266                                                                  use_requested_addr,
1267                                                                  total_space_rs,
1268                                                                  archive_space_rs,
1269                                                                  class_space_rs);
1270   if (mapped_base_address == nullptr) {
1271     result = MAP_ARCHIVE_MMAP_FAILURE;
1272     log_debug(cds)("Failed to reserve spaces (use_requested_addr=%u)", (unsigned)use_requested_addr);
1273   } else {
1274 
1275     if (Metaspace::using_class_space()) {
1276       prot_zone_size = protection_zone_size();
1277     }
1278 
1279 #ifdef ASSERT
1280     // Some sanity checks after reserving address spaces for archives
1281     //  and class space.
1282     assert(archive_space_rs.is_reserved(), "Sanity");
1283     if (Metaspace::using_class_space()) {
1284       assert(archive_space_rs.base() == mapped_base_address &&
1285           archive_space_rs.size() > protection_zone_size(),
1286           "Archive space must lead and include the protection zone");
1287       // Class space must closely follow the archive space. Both spaces
1288       //  must be aligned correctly.
1289       assert(class_space_rs.is_reserved() && class_space_rs.size() > 0,
1290              "A class space should have been reserved");
1291       assert(class_space_rs.base() >= archive_space_rs.end(),
1292              "class space should follow the cds archive space");
1293       assert(is_aligned(archive_space_rs.base(),
1294                         core_region_alignment()),
1295              "Archive space misaligned");
1296       assert(is_aligned(class_space_rs.base(),
1297                         Metaspace::reserve_alignment()),
1298              "class space misaligned");
1299     }
1300 #endif // ASSERT
1301 
1302     log_info(cds)("Reserved archive_space_rs [" INTPTR_FORMAT " - " INTPTR_FORMAT "] (%zu) bytes%s",
1303                    p2i(archive_space_rs.base()), p2i(archive_space_rs.end()), archive_space_rs.size(),
1304                    (prot_zone_size > 0 ? " (includes protection zone)" : ""));
1305     log_info(cds)("Reserved class_space_rs   [" INTPTR_FORMAT " - " INTPTR_FORMAT "] (%zu) bytes",
1306                    p2i(class_space_rs.base()), p2i(class_space_rs.end()), class_space_rs.size());
1307 
1308     if (MetaspaceShared::use_windows_memory_mapping()) {
1309       // We have now reserved address space for the archives, and will map in
1310       //  the archive files into this space.
1311       //
1312       // Special handling for Windows: on Windows we cannot map a file view
1313       //  into an existing memory mapping. So, we unmap the address range we
1314       //  just reserved again, which will make it available for mapping the
1315       //  archives.
1316       // Reserving this range has not been for naught however since it makes
1317       //  us reasonably sure the address range is available.
1318       //
1319       // But still it may fail, since between unmapping the range and mapping
1320       //  in the archive someone else may grab the address space. Therefore
1321       //  there is a fallback in FileMap::map_region() where we just read in
1322       //  the archive files sequentially instead of mapping it in. We couple
1323       //  this with use_requested_addr, since we're going to patch all the
1324       //  pointers anyway so there's no benefit to mmap.
1325       if (use_requested_addr) {
1326         assert(!total_space_rs.is_reserved(), "Should not be reserved for Windows");
1327         log_info(cds)("Windows mmap workaround: releasing archive space.");
1328         MemoryReserver::release(archive_space_rs);
1329         // Mark as not reserved
1330         archive_space_rs = {};
1331         // The protection zone is part of the archive:
1332         // See comment above, the Windows way of loading CDS is to mmap the individual
1333         // parts of the archive into the address region we just vacated. The protection
1334         // zone will not be mapped (and, in fact, does not exist as physical region in
1335         // the archive). Therefore, after removing the archive space above, we must
1336         // re-reserve the protection zone part lest something else gets mapped into that
1337         // area later.
1338         if (prot_zone_size > 0) {
1339           assert(prot_zone_size >= os::vm_allocation_granularity(), "must be"); // not just page size!
1340           char* p = os::attempt_reserve_memory_at(mapped_base_address, prot_zone_size,
1341                                                   mtClassShared);
1342           assert(p == mapped_base_address || p == nullptr, "must be");
1343           if (p == nullptr) {
1344             log_debug(cds)("Failed to re-reserve protection zone");
1345             return MAP_ARCHIVE_MMAP_FAILURE;
1346           }
1347         }
1348       }
1349     }
1350 
1351     if (prot_zone_size > 0) {
1352       os::commit_memory(mapped_base_address, prot_zone_size, false); // will later be protected
1353       // Before mapping the core regions into the newly established address space, we mark
1354       // start and the end of the future protection zone with canaries. That way we easily
1355       // catch mapping errors (accidentally mapping data into the future protection zone).
1356       *(mapped_base_address) = 'P';
1357       *(mapped_base_address + prot_zone_size - 1) = 'P';
1358     }
1359 
1360     MapArchiveResult static_result = map_archive(static_mapinfo, mapped_base_address, archive_space_rs);
1361     MapArchiveResult dynamic_result = (static_result == MAP_ARCHIVE_SUCCESS) ?
1362                                      map_archive(dynamic_mapinfo, mapped_base_address, archive_space_rs) : MAP_ARCHIVE_OTHER_FAILURE;
1363 
1364     DEBUG_ONLY(if (ArchiveRelocationMode == 1 && use_requested_addr) {
1365       // This is for simulating mmap failures at the requested address. In
1366       //  debug builds, we do it here (after all archives have possibly been
1367       //  mapped), so we can thoroughly test the code for failure handling
1368       //  (releasing all allocated resource, etc).
1369       log_info(cds)("ArchiveRelocationMode == 1: always map archive(s) at an alternative address");
1370       if (static_result == MAP_ARCHIVE_SUCCESS) {
1371         static_result = MAP_ARCHIVE_MMAP_FAILURE;
1372       }
1373       if (dynamic_result == MAP_ARCHIVE_SUCCESS) {
1374         dynamic_result = MAP_ARCHIVE_MMAP_FAILURE;
1375       }
1376     });
1377 
1378     if (static_result == MAP_ARCHIVE_SUCCESS) {
1379       if (dynamic_result == MAP_ARCHIVE_SUCCESS) {
1380         result = MAP_ARCHIVE_SUCCESS;
1381       } else if (dynamic_result == MAP_ARCHIVE_OTHER_FAILURE) {
1382         assert(dynamic_mapinfo != nullptr && !dynamic_mapinfo->is_mapped(), "must have failed");
1383         // No need to retry mapping the dynamic archive again, as it will never succeed
1384         // (bad file, etc) -- just keep the base archive.
1385         log_warning(cds, dynamic)("Unable to use shared archive. The top archive failed to load: %s",
1386                                   dynamic_mapinfo->full_path());
1387         result = MAP_ARCHIVE_SUCCESS;
1388         // TODO, we can give the unused space for the dynamic archive to class_space_rs, but there's no
1389         // easy API to do that right now.
1390       } else {
1391         result = MAP_ARCHIVE_MMAP_FAILURE;
1392       }
1393     } else if (static_result == MAP_ARCHIVE_OTHER_FAILURE) {
1394       result = MAP_ARCHIVE_OTHER_FAILURE;
1395     } else {
1396       result = MAP_ARCHIVE_MMAP_FAILURE;
1397     }
1398   }
1399 
1400   if (result == MAP_ARCHIVE_SUCCESS) {
1401     SharedBaseAddress = (size_t)mapped_base_address;
1402 #ifdef _LP64
1403     if (Metaspace::using_class_space()) {
1404       assert(prot_zone_size > 0 &&
1405              *(mapped_base_address) == 'P' &&
1406              *(mapped_base_address + prot_zone_size - 1) == 'P',
1407              "Protection zone was overwritten?");
1408       // Set up ccs in metaspace.
1409       Metaspace::initialize_class_space(class_space_rs);
1410 
1411       // Set up compressed Klass pointer encoding: the encoding range must
1412       //  cover both archive and class space.
1413       const address encoding_base = (address)mapped_base_address;
1414       const address klass_range_start = encoding_base + prot_zone_size;
1415       const size_t klass_range_size = (address)class_space_rs.end() - klass_range_start;
1416       if (INCLUDE_CDS_JAVA_HEAP || UseCompactObjectHeaders) {
1417         // The CDS archive may contain narrow Klass IDs that were precomputed at archive generation time:
1418         // - every archived java object header (only if INCLUDE_CDS_JAVA_HEAP)
1419         // - every archived Klass' prototype   (only if +UseCompactObjectHeaders)
1420         //
1421         // In order for those IDs to still be valid, we need to dictate base and shift: base should be the
1422         // mapping start (including protection zone), shift should be the shift used at archive generation time.
1423         CompressedKlassPointers::initialize_for_given_encoding(
1424           klass_range_start, klass_range_size,
1425           encoding_base, ArchiveBuilder::precomputed_narrow_klass_shift() // precomputed encoding, see ArchiveBuilder
1426         );
1427       } else {
1428         // Let JVM freely choose encoding base and shift
1429         CompressedKlassPointers::initialize(klass_range_start, klass_range_size);
1430       }
1431       CompressedKlassPointers::establish_protection_zone(encoding_base, prot_zone_size);
1432 
1433       // map_or_load_heap_region() compares the current narrow oop and klass encodings
1434       // with the archived ones, so it must be done after all encodings are determined.
1435       static_mapinfo->map_or_load_heap_region();
1436     }
1437 #endif // _LP64
1438     log_info(cds)("initial optimized module handling: %s", CDSConfig::is_using_optimized_module_handling() ? "enabled" : "disabled");
1439     log_info(cds)("initial full module graph: %s", CDSConfig::is_using_full_module_graph() ? "enabled" : "disabled");
1440   } else {
1441     unmap_archive(static_mapinfo);
1442     unmap_archive(dynamic_mapinfo);
1443     release_reserved_spaces(total_space_rs, archive_space_rs, class_space_rs);
1444   }
1445 
1446   return result;
1447 }
1448 
1449 
1450 // This will reserve two address spaces suitable to house Klass structures, one
1451 //  for the cds archives (static archive and optionally dynamic archive) and
1452 //  optionally one move for ccs.
1453 //
1454 // Since both spaces must fall within the compressed class pointer encoding
1455 //  range, they are allocated close to each other.
1456 //
1457 // Space for archives will be reserved first, followed by a potential gap,
1458 //  followed by the space for ccs:
1459 //
1460 // +-- Base address             A        B                     End
1461 // |                            |        |                      |
1462 // v                            v        v                      v
1463 // +-------------+--------------+        +----------------------+
1464 // | static arc  | [dyn. arch]  | [gap]  | compr. class space   |
1465 // +-------------+--------------+        +----------------------+
1466 //
1467 // (The gap may result from different alignment requirements between metaspace
1468 //  and CDS)
1469 //
1470 // If UseCompressedClassPointers is disabled, only one address space will be
1471 //  reserved:
1472 //
1473 // +-- Base address             End
1474 // |                            |
1475 // v                            v
1476 // +-------------+--------------+
1477 // | static arc  | [dyn. arch]  |
1478 // +-------------+--------------+
1479 //
1480 // Base address: If use_archive_base_addr address is true, the Base address is
1481 //  determined by the address stored in the static archive. If
1482 //  use_archive_base_addr address is false, this base address is determined
1483 //  by the platform.
1484 //
1485 // If UseCompressedClassPointers=1, the range encompassing both spaces will be
1486 //  suitable to en/decode narrow Klass pointers: the base will be valid for
1487 //  encoding, the range [Base, End) and not surpass the max. range for that encoding.
1488 //
1489 // Return:
1490 //
1491 // - On success:
1492 //    - total_space_rs will be reserved as whole for archive_space_rs and
1493 //      class_space_rs if UseCompressedClassPointers is true.
1494 //      On Windows, try reserve archive_space_rs and class_space_rs
1495 //      separately first if use_archive_base_addr is true.
1496 //    - archive_space_rs will be reserved and large enough to host static and
1497 //      if needed dynamic archive: [Base, A).
1498 //      archive_space_rs.base and size will be aligned to CDS reserve
1499 //      granularity.
1500 //    - class_space_rs: If UseCompressedClassPointers=1, class_space_rs will
1501 //      be reserved. Its start address will be aligned to metaspace reserve
1502 //      alignment, which may differ from CDS alignment. It will follow the cds
1503 //      archive space, close enough such that narrow class pointer encoding
1504 //      covers both spaces.
1505 //      If UseCompressedClassPointers=0, class_space_rs remains unreserved.
1506 // - On error: null is returned and the spaces remain unreserved.
1507 char* MetaspaceShared::reserve_address_space_for_archives(FileMapInfo* static_mapinfo,
1508                                                           FileMapInfo* dynamic_mapinfo,
1509                                                           bool use_archive_base_addr,
1510                                                           ReservedSpace& total_space_rs,
1511                                                           ReservedSpace& archive_space_rs,
1512                                                           ReservedSpace& class_space_rs) {
1513 
1514   address const base_address = (address) (use_archive_base_addr ? static_mapinfo->requested_base_address() : nullptr);
1515   const size_t archive_space_alignment = core_region_alignment();
1516 
1517   // Size and requested location of the archive_space_rs (for both static and dynamic archives)
1518   size_t archive_end_offset  = (dynamic_mapinfo == nullptr) ? static_mapinfo->mapping_end_offset() : dynamic_mapinfo->mapping_end_offset();
1519   size_t archive_space_size = align_up(archive_end_offset, archive_space_alignment);
1520 
1521   if (!Metaspace::using_class_space()) {
1522     // Get the simple case out of the way first:
1523     // no compressed class space, simple allocation.
1524 
1525     // When running without class space, requested archive base should be aligned to cds core alignment.
1526     assert(is_aligned(base_address, archive_space_alignment),
1527              "Archive base address unaligned: " PTR_FORMAT ", needs alignment: %zu.",
1528              p2i(base_address), archive_space_alignment);
1529 
1530     archive_space_rs = MemoryReserver::reserve((char*)base_address,
1531                                                archive_space_size,
1532                                                archive_space_alignment,
1533                                                os::vm_page_size(),
1534                                                mtNone);
1535     if (archive_space_rs.is_reserved()) {
1536       assert(base_address == nullptr ||
1537              (address)archive_space_rs.base() == base_address, "Sanity");
1538       // Register archive space with NMT.
1539       MemTracker::record_virtual_memory_tag(archive_space_rs, mtClassShared);
1540       return archive_space_rs.base();
1541     }
1542     return nullptr;
1543   }
1544 
1545 #ifdef _LP64
1546 
1547   // Complex case: two spaces adjacent to each other, both to be addressable
1548   //  with narrow class pointers.
1549   // We reserve the whole range spanning both spaces, then split that range up.
1550 
1551   const size_t class_space_alignment = Metaspace::reserve_alignment();
1552 
1553   // When running with class space, requested archive base must satisfy both cds core alignment
1554   // and class space alignment.
1555   const size_t base_address_alignment = MAX2(class_space_alignment, archive_space_alignment);
1556   assert(is_aligned(base_address, base_address_alignment),
1557            "Archive base address unaligned: " PTR_FORMAT ", needs alignment: %zu.",
1558            p2i(base_address), base_address_alignment);
1559 
1560   size_t class_space_size = CompressedClassSpaceSize;
1561   assert(CompressedClassSpaceSize > 0 &&
1562          is_aligned(CompressedClassSpaceSize, class_space_alignment),
1563          "CompressedClassSpaceSize malformed: %zu", CompressedClassSpaceSize);
1564 
1565   const size_t ccs_begin_offset = align_up(archive_space_size, class_space_alignment);
1566   const size_t gap_size = ccs_begin_offset - archive_space_size;
1567 
1568   // Reduce class space size if it would not fit into the Klass encoding range
1569   constexpr size_t max_encoding_range_size = 4 * G;
1570   guarantee(archive_space_size < max_encoding_range_size - class_space_alignment, "Archive too large");
1571   if ((archive_space_size + gap_size + class_space_size) > max_encoding_range_size) {
1572     class_space_size = align_down(max_encoding_range_size - archive_space_size - gap_size, class_space_alignment);
1573     log_info(metaspace)("CDS initialization: reducing class space size from %zu to %zu",
1574         CompressedClassSpaceSize, class_space_size);
1575     FLAG_SET_ERGO(CompressedClassSpaceSize, class_space_size);
1576   }
1577 
1578   const size_t total_range_size =
1579       archive_space_size + gap_size + class_space_size;
1580 
1581   // Test that class space base address plus shift can be decoded by aarch64, when restored.
1582   const int precomputed_narrow_klass_shift = ArchiveBuilder::precomputed_narrow_klass_shift();
1583   if (!CompressedKlassPointers::check_klass_decode_mode(base_address, precomputed_narrow_klass_shift,
1584                                                         total_range_size)) {
1585     log_info(cds)("CDS initialization: Cannot use SharedBaseAddress " PTR_FORMAT " with precomputed shift %d.",
1586                   p2i(base_address), precomputed_narrow_klass_shift);
1587     use_archive_base_addr = false;
1588   }
1589 
1590   assert(total_range_size > ccs_begin_offset, "must be");
1591   if (use_windows_memory_mapping() && use_archive_base_addr) {
1592     if (base_address != nullptr) {
1593       // On Windows, we cannot safely split a reserved memory space into two (see JDK-8255917).
1594       // Hence, we optimistically reserve archive space and class space side-by-side. We only
1595       // do this for use_archive_base_addr=true since for use_archive_base_addr=false case
1596       // caller will not split the combined space for mapping, instead read the archive data
1597       // via sequential file IO.
1598       address ccs_base = base_address + archive_space_size + gap_size;
1599       archive_space_rs = MemoryReserver::reserve((char*)base_address,
1600                                                  archive_space_size,
1601                                                  archive_space_alignment,
1602                                                  os::vm_page_size(),
1603                                                  mtNone);
1604       class_space_rs   = MemoryReserver::reserve((char*)ccs_base,
1605                                                  class_space_size,
1606                                                  class_space_alignment,
1607                                                  os::vm_page_size(),
1608                                                  mtNone);
1609     }
1610     if (!archive_space_rs.is_reserved() || !class_space_rs.is_reserved()) {
1611       release_reserved_spaces(total_space_rs, archive_space_rs, class_space_rs);
1612       return nullptr;
1613     }
1614     MemTracker::record_virtual_memory_tag(archive_space_rs, mtClassShared);
1615     MemTracker::record_virtual_memory_tag(class_space_rs, mtClass);
1616   } else {
1617     if (use_archive_base_addr && base_address != nullptr) {
1618       total_space_rs = MemoryReserver::reserve((char*) base_address,
1619                                                total_range_size,
1620                                                base_address_alignment,
1621                                                os::vm_page_size(),
1622                                                mtNone);
1623     } else {
1624       // We did not manage to reserve at the preferred address, or were instructed to relocate. In that
1625       // case we reserve wherever possible, but the start address needs to be encodable as narrow Klass
1626       // encoding base since the archived heap objects contain narrow Klass IDs pre-calculated toward the start
1627       // of the shared Metaspace. That prevents us from using zero-based encoding and therefore we won't
1628       // try allocating in low-address regions.
1629       total_space_rs = Metaspace::reserve_address_space_for_compressed_classes(total_range_size, false /* optimize_for_zero_base */);
1630     }
1631 
1632     if (!total_space_rs.is_reserved()) {
1633       return nullptr;
1634     }
1635 
1636     // Paranoid checks:
1637     assert(!use_archive_base_addr || (address)total_space_rs.base() == base_address,
1638            "Sanity (" PTR_FORMAT " vs " PTR_FORMAT ")", p2i(base_address), p2i(total_space_rs.base()));
1639     assert(is_aligned(total_space_rs.base(), base_address_alignment), "Sanity");
1640     assert(total_space_rs.size() == total_range_size, "Sanity");
1641 
1642     // Now split up the space into ccs and cds archive. For simplicity, just leave
1643     //  the gap reserved at the end of the archive space. Do not do real splitting.
1644     archive_space_rs = total_space_rs.first_part(ccs_begin_offset,
1645                                                  (size_t)archive_space_alignment);
1646     class_space_rs = total_space_rs.last_part(ccs_begin_offset);
1647     MemTracker::record_virtual_memory_split_reserved(total_space_rs.base(), total_space_rs.size(),
1648                                                      ccs_begin_offset, mtClassShared, mtClass);
1649   }
1650   assert(is_aligned(archive_space_rs.base(), archive_space_alignment), "Sanity");
1651   assert(is_aligned(archive_space_rs.size(), archive_space_alignment), "Sanity");
1652   assert(is_aligned(class_space_rs.base(), class_space_alignment), "Sanity");
1653   assert(is_aligned(class_space_rs.size(), class_space_alignment), "Sanity");
1654 
1655 
1656   return archive_space_rs.base();
1657 
1658 #else
1659   ShouldNotReachHere();
1660   return nullptr;
1661 #endif
1662 
1663 }
1664 
1665 void MetaspaceShared::release_reserved_spaces(ReservedSpace& total_space_rs,
1666                                               ReservedSpace& archive_space_rs,
1667                                               ReservedSpace& class_space_rs) {
1668   if (total_space_rs.is_reserved()) {
1669     log_debug(cds)("Released shared space (archive + class) " INTPTR_FORMAT, p2i(total_space_rs.base()));
1670     MemoryReserver::release(total_space_rs);
1671     total_space_rs = {};
1672   } else {
1673     if (archive_space_rs.is_reserved()) {
1674       log_debug(cds)("Released shared space (archive) " INTPTR_FORMAT, p2i(archive_space_rs.base()));
1675       MemoryReserver::release(archive_space_rs);
1676       archive_space_rs = {};
1677     }
1678     if (class_space_rs.is_reserved()) {
1679       log_debug(cds)("Released shared space (classes) " INTPTR_FORMAT, p2i(class_space_rs.base()));
1680       MemoryReserver::release(class_space_rs);
1681       class_space_rs = {};
1682     }
1683   }
1684 }
1685 
1686 static int archive_regions[]     = { MetaspaceShared::rw, MetaspaceShared::ro };
1687 static int archive_regions_count = 2;
1688 
1689 MapArchiveResult MetaspaceShared::map_archive(FileMapInfo* mapinfo, char* mapped_base_address, ReservedSpace rs) {
1690   assert(CDSConfig::is_using_archive(), "must be runtime");
1691   if (mapinfo == nullptr) {
1692     return MAP_ARCHIVE_SUCCESS; // The dynamic archive has not been specified. No error has happened -- trivially succeeded.
1693   }
1694 
1695   mapinfo->set_is_mapped(false);
1696   if (mapinfo->core_region_alignment() != (size_t)core_region_alignment()) {
1697     log_info(cds)("Unable to map CDS archive -- core_region_alignment() expected: %zu"
1698                   " actual: %zu", mapinfo->core_region_alignment(), core_region_alignment());
1699     return MAP_ARCHIVE_OTHER_FAILURE;
1700   }
1701 
1702   MapArchiveResult result =
1703     mapinfo->map_regions(archive_regions, archive_regions_count, mapped_base_address, rs);
1704 
1705   if (result != MAP_ARCHIVE_SUCCESS) {
1706     unmap_archive(mapinfo);
1707     return result;
1708   }
1709 
1710   if (!mapinfo->validate_class_location()) {
1711     unmap_archive(mapinfo);
1712     return MAP_ARCHIVE_OTHER_FAILURE;
1713   }
1714 
1715   if (mapinfo->is_static()) {
1716     // Currently, only static archive uses early serialized data.
1717     char* buffer = mapinfo->early_serialized_data();
1718     intptr_t* array = (intptr_t*)buffer;
1719     ReadClosure rc(&array, (intptr_t)mapped_base_address);
1720     early_serialize(&rc);
1721   }
1722 
1723   if (!mapinfo->validate_aot_class_linking()) {
1724     unmap_archive(mapinfo);
1725     return MAP_ARCHIVE_OTHER_FAILURE;
1726   }
1727 
1728   mapinfo->set_is_mapped(true);
1729   return MAP_ARCHIVE_SUCCESS;
1730 }
1731 
1732 void MetaspaceShared::unmap_archive(FileMapInfo* mapinfo) {
1733   assert(CDSConfig::is_using_archive(), "must be runtime");
1734   if (mapinfo != nullptr) {
1735     mapinfo->unmap_regions(archive_regions, archive_regions_count);
1736     mapinfo->unmap_region(MetaspaceShared::bm);
1737     mapinfo->set_is_mapped(false);
1738   }
1739 }
1740 
1741 // For -XX:PrintSharedArchiveAndExit
1742 class CountSharedSymbols : public SymbolClosure {
1743  private:
1744    int _count;
1745  public:
1746    CountSharedSymbols() : _count(0) {}
1747   void do_symbol(Symbol** sym) {
1748     _count++;
1749   }
1750   int total() { return _count; }
1751 
1752 };
1753 
1754 // Read the miscellaneous data from the shared file, and
1755 // serialize it out to its various destinations.
1756 
1757 void MetaspaceShared::initialize_shared_spaces() {
1758   FileMapInfo *static_mapinfo = FileMapInfo::current_info();
1759 
1760   // Verify various attributes of the archive, plus initialize the
1761   // shared string/symbol tables.
1762   char* buffer = static_mapinfo->serialized_data();
1763   intptr_t* array = (intptr_t*)buffer;
1764   ReadClosure rc(&array, (intptr_t)SharedBaseAddress);
1765   serialize(&rc);
1766 
1767   // Finish up archived heap initialization. These must be
1768   // done after ReadClosure.
1769   static_mapinfo->patch_heap_embedded_pointers();
1770   ArchiveHeapLoader::finish_initialization();
1771   Universe::load_archived_object_instances();
1772 
1773   // Close the mapinfo file
1774   static_mapinfo->close();
1775 
1776   static_mapinfo->unmap_region(MetaspaceShared::bm);
1777 
1778   FileMapInfo *dynamic_mapinfo = FileMapInfo::dynamic_info();
1779   if (dynamic_mapinfo != nullptr) {
1780     intptr_t* buffer = (intptr_t*)dynamic_mapinfo->serialized_data();
1781     ReadClosure rc(&buffer, (intptr_t)SharedBaseAddress);
1782     ArchiveBuilder::serialize_dynamic_archivable_items(&rc);
1783     DynamicArchive::setup_array_klasses();
1784     dynamic_mapinfo->close();
1785     dynamic_mapinfo->unmap_region(MetaspaceShared::bm);
1786   }
1787 
1788   LogStreamHandle(Info, cds) lsh;
1789   if (lsh.is_enabled()) {
1790     lsh.print("Using AOT-linked classes: %s (static archive: %s aot-linked classes",
1791               BOOL_TO_STR(CDSConfig::is_using_aot_linked_classes()),
1792               static_mapinfo->header()->has_aot_linked_classes() ? "has" : "no");
1793     if (dynamic_mapinfo != nullptr) {
1794       lsh.print(", dynamic archive: %s aot-linked classes",
1795                 dynamic_mapinfo->header()->has_aot_linked_classes() ? "has" : "no");
1796     }
1797     lsh.print_cr(")");
1798   }
1799 
1800   // Set up LambdaFormInvokers::_lambdaform_lines for dynamic dump
1801   if (CDSConfig::is_dumping_dynamic_archive()) {
1802     // Read stored LF format lines stored in static archive
1803     LambdaFormInvokers::read_static_archive_invokers();
1804   }
1805 
1806   if (PrintSharedArchiveAndExit) {
1807     // Print archive names
1808     if (dynamic_mapinfo != nullptr) {
1809       tty->print_cr("\n\nBase archive name: %s", CDSConfig::input_static_archive_path());
1810       tty->print_cr("Base archive version %d", static_mapinfo->version());
1811     } else {
1812       tty->print_cr("Static archive name: %s", static_mapinfo->full_path());
1813       tty->print_cr("Static archive version %d", static_mapinfo->version());
1814     }
1815 
1816     SystemDictionaryShared::print_shared_archive(tty);
1817     if (dynamic_mapinfo != nullptr) {
1818       tty->print_cr("\n\nDynamic archive name: %s", dynamic_mapinfo->full_path());
1819       tty->print_cr("Dynamic archive version %d", dynamic_mapinfo->version());
1820       SystemDictionaryShared::print_shared_archive(tty, false/*dynamic*/);
1821     }
1822 
1823     // collect shared symbols and strings
1824     CountSharedSymbols cl;
1825     SymbolTable::shared_symbols_do(&cl);
1826     tty->print_cr("Number of shared symbols: %d", cl.total());
1827     tty->print_cr("Number of shared strings: %zu", StringTable::shared_entry_count());
1828     tty->print_cr("VM version: %s\r\n", static_mapinfo->vm_version());
1829     if (FileMapInfo::current_info() == nullptr || _archive_loading_failed) {
1830       tty->print_cr("archive is invalid");
1831       vm_exit(1);
1832     } else {
1833       tty->print_cr("archive is valid");
1834       vm_exit(0);
1835     }
1836   }
1837 }
1838 
1839 // JVM/TI RedefineClasses() support:
1840 bool MetaspaceShared::remap_shared_readonly_as_readwrite() {
1841   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1842 
1843   if (CDSConfig::is_using_archive()) {
1844     // remap the shared readonly space to shared readwrite, private
1845     FileMapInfo* mapinfo = FileMapInfo::current_info();
1846     if (!mapinfo->remap_shared_readonly_as_readwrite()) {
1847       return false;
1848     }
1849     if (FileMapInfo::dynamic_info() != nullptr) {
1850       mapinfo = FileMapInfo::dynamic_info();
1851       if (!mapinfo->remap_shared_readonly_as_readwrite()) {
1852         return false;
1853       }
1854     }
1855     _remapped_readwrite = true;
1856   }
1857   return true;
1858 }
1859 
1860 void MetaspaceShared::print_on(outputStream* st) {
1861   if (CDSConfig::is_using_archive()) {
1862     st->print("CDS archive(s) mapped at: ");
1863     address base = (address)MetaspaceObj::shared_metaspace_base();
1864     address static_top = (address)_shared_metaspace_static_top;
1865     address top = (address)MetaspaceObj::shared_metaspace_top();
1866     st->print("[" PTR_FORMAT "-" PTR_FORMAT "-" PTR_FORMAT "), ", p2i(base), p2i(static_top), p2i(top));
1867     st->print("size %zu, ", top - base);
1868     st->print("SharedBaseAddress: " PTR_FORMAT ", ArchiveRelocationMode: %d.", SharedBaseAddress, ArchiveRelocationMode);
1869   } else {
1870     st->print("CDS archive(s) not mapped");
1871   }
1872   st->cr();
1873 }