1 /*
   2  * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "jvm.h"
  27 #include "classfile/classListParser.hpp"
  28 #include "classfile/classLoaderExt.hpp"
  29 #include "classfile/dictionary.hpp"
  30 #include "classfile/loaderConstraints.hpp"
  31 #include "classfile/placeholders.hpp"
  32 #include "classfile/symbolTable.hpp"
  33 #include "classfile/stringTable.hpp"
  34 #include "classfile/systemDictionary.hpp"
  35 #include "classfile/systemDictionaryShared.hpp"
  36 #include "code/codeCache.hpp"
  37 #include "interpreter/bytecodeStream.hpp"
  38 #include "interpreter/bytecodes.hpp"
  39 #include "logging/log.hpp"
  40 #include "logging/logMessage.hpp"
  41 #include "memory/filemap.hpp"
  42 #include "memory/heapShared.hpp"
  43 #include "memory/metaspace.hpp"
  44 #include "memory/metaspaceClosure.hpp"
  45 #include "memory/metaspaceShared.hpp"
  46 #include "memory/resourceArea.hpp"
  47 #include "oops/compressedOops.inline.hpp"
  48 #include "oops/instanceClassLoaderKlass.hpp"
  49 #include "oops/instanceMirrorKlass.hpp"
  50 #include "oops/instanceRefKlass.hpp"
  51 #include "oops/objArrayKlass.hpp"
  52 #include "oops/objArrayOop.hpp"
  53 #include "oops/oop.inline.hpp"
  54 #include "oops/typeArrayKlass.hpp"
  55 #include "prims/jvmtiRedefineClasses.hpp"
  56 #include "runtime/handles.inline.hpp"
  57 #include "runtime/os.hpp"
  58 #include "runtime/safepointVerifiers.hpp"
  59 #include "runtime/signature.hpp"
  60 #include "runtime/timerTrace.hpp"
  61 #include "runtime/vmThread.hpp"
  62 #include "runtime/vm_operations.hpp"
  63 #include "utilities/align.hpp"
  64 #include "utilities/defaultStream.hpp"
  65 #include "utilities/hashtable.inline.hpp"
  66 #if INCLUDE_G1GC
  67 #include "gc/g1/g1Allocator.inline.hpp"
  68 #include "gc/g1/g1CollectedHeap.hpp"
  69 #endif
  70 
  71 ReservedSpace MetaspaceShared::_shared_rs;
  72 VirtualSpace MetaspaceShared::_shared_vs;
  73 MetaspaceSharedStats MetaspaceShared::_stats;
  74 bool MetaspaceShared::_has_error_classes;
  75 bool MetaspaceShared::_archive_loading_failed = false;
  76 bool MetaspaceShared::_remapped_readwrite = false;
  77 bool MetaspaceShared::_open_archive_heap_region_mapped = false;
  78 address MetaspaceShared::_cds_i2i_entry_code_buffers = NULL;
  79 size_t MetaspaceShared::_cds_i2i_entry_code_buffers_size = 0;
  80 size_t MetaspaceShared::_core_spaces_size = 0;
  81 
  82 // The CDS archive is divided into the following regions:
  83 //     mc  - misc code (the method entry trampolines)
  84 //     rw  - read-write metadata
  85 //     ro  - read-only metadata and read-only tables
  86 //     md  - misc data (the c++ vtables)
  87 //     od  - optional data (original class files)
  88 //
  89 //     s0  - shared strings(closed archive heap space) #0
  90 //     s1  - shared strings(closed archive heap space) #1 (may be empty)
  91 //     oa0 - open archive heap space #0
  92 //     oa1 - open archive heap space #1 (may be empty)
  93 //
  94 // The mc, rw, ro, md and od regions are linearly allocated, starting from
  95 // SharedBaseAddress, in the order of mc->rw->ro->md->od. The size of these 5 regions
  96 // are page-aligned, and there's no gap between any consecutive regions.
  97 //
  98 // These 5 regions are populated in the following steps:
  99 // [1] All classes are loaded in MetaspaceShared::preload_classes(). All metadata are
 100 //     temporarily allocated outside of the shared regions. Only the method entry
 101 //     trampolines are written into the mc region.
 102 // [2] ArchiveCompactor copies RW metadata into the rw region.
 103 // [3] ArchiveCompactor copies RO metadata into the ro region.
 104 // [4] SymbolTable, StringTable, SystemDictionary, and a few other read-only data
 105 //     are copied into the ro region as read-only tables.
 106 // [5] C++ vtables are copied into the md region.
 107 // [6] Original class files are copied into the od region.
 108 //
 109 // The s0/s1 and oa0/oa1 regions are populated inside MetaspaceShared::dump_java_heap_objects.
 110 // Their layout is independent of the other 5 regions.
 111 
 112 class DumpRegion {
 113 private:
 114   const char* _name;
 115   char* _base;
 116   char* _top;
 117   char* _end;
 118   bool _is_packed;
 119 
 120   char* expand_top_to(char* newtop) {
 121     assert(is_allocatable(), "must be initialized and not packed");
 122     assert(newtop >= _top, "must not grow backwards");
 123     if (newtop > _end) {
 124       MetaspaceShared::report_out_of_space(_name, newtop - _top);
 125       ShouldNotReachHere();
 126     }
 127     MetaspaceShared::commit_shared_space_to(newtop);
 128     _top = newtop;
 129     return _top;
 130   }
 131 
 132 public:
 133   DumpRegion(const char* name) : _name(name), _base(NULL), _top(NULL), _end(NULL), _is_packed(false) {}
 134 
 135   char* allocate(size_t num_bytes, size_t alignment=BytesPerWord) {
 136     char* p = (char*)align_up(_top, alignment);
 137     char* newtop = p + align_up(num_bytes, alignment);
 138     expand_top_to(newtop);
 139     memset(p, 0, newtop - p);
 140     return p;
 141   }
 142 
 143   void append_intptr_t(intptr_t n) {
 144     assert(is_aligned(_top, sizeof(intptr_t)), "bad alignment");
 145     intptr_t *p = (intptr_t*)_top;
 146     char* newtop = _top + sizeof(intptr_t);
 147     expand_top_to(newtop);
 148     *p = n;
 149   }
 150 
 151   char* base()      const { return _base;        }
 152   char* top()       const { return _top;         }
 153   char* end()       const { return _end;         }
 154   size_t reserved() const { return _end - _base; }
 155   size_t used()     const { return _top - _base; }
 156   bool is_packed()  const { return _is_packed;   }
 157   bool is_allocatable() const {
 158     return !is_packed() && _base != NULL;
 159   }
 160 
 161   void print(size_t total_bytes) const {
 162     tty->print_cr("%-3s space: " SIZE_FORMAT_W(9) " [ %4.1f%% of total] out of " SIZE_FORMAT_W(9) " bytes [%5.1f%% used] at " INTPTR_FORMAT,
 163                   _name, used(), percent_of(used(), total_bytes), reserved(), percent_of(used(), reserved()), p2i(_base));
 164   }
 165   void print_out_of_space_msg(const char* failing_region, size_t needed_bytes) {
 166     tty->print("[%-8s] " PTR_FORMAT " - " PTR_FORMAT " capacity =%9d, allocated =%9d",
 167                _name, p2i(_base), p2i(_top), int(_end - _base), int(_top - _base));
 168     if (strcmp(_name, failing_region) == 0) {
 169       tty->print_cr(" required = %d", int(needed_bytes));
 170     } else {
 171       tty->cr();
 172     }
 173   }
 174 
 175   void init(const ReservedSpace* rs) {
 176     _base = _top = rs->base();
 177     _end = rs->end();
 178   }
 179   void init(char* b, char* t, char* e) {
 180     _base = b;
 181     _top = t;
 182     _end = e;
 183   }
 184 
 185   void pack(DumpRegion* next = NULL) {
 186     assert(!is_packed(), "sanity");
 187     _end = (char*)align_up(_top, Metaspace::reserve_alignment());
 188     _is_packed = true;
 189     if (next != NULL) {
 190       next->_base = next->_top = this->_end;
 191       next->_end = MetaspaceShared::shared_rs()->end();
 192     }
 193   }
 194   bool contains(char* p) {
 195     return base() <= p && p < top();
 196   }
 197 };
 198 
 199 
 200 DumpRegion _mc_region("mc"), _ro_region("ro"), _rw_region("rw"), _md_region("md"), _od_region("od");
 201 size_t _total_string_region_size = 0, _total_open_archive_region_size = 0;
 202 
 203 char* MetaspaceShared::misc_code_space_alloc(size_t num_bytes) {
 204   return _mc_region.allocate(num_bytes);
 205 }
 206 
 207 char* MetaspaceShared::read_only_space_alloc(size_t num_bytes) {
 208   return _ro_region.allocate(num_bytes);
 209 }
 210 
 211 char* MetaspaceShared::read_only_space_top() {
 212   return _ro_region.top();
 213 }
 214 
 215 void MetaspaceShared::initialize_runtime_shared_and_meta_spaces() {
 216   assert(UseSharedSpaces, "Must be called when UseSharedSpaces is enabled");
 217 
 218   // If using shared space, open the file that contains the shared space
 219   // and map in the memory before initializing the rest of metaspace (so
 220   // the addresses don't conflict)
 221   address cds_address = NULL;
 222   FileMapInfo* mapinfo = new FileMapInfo();
 223 
 224   // Open the shared archive file, read and validate the header. If
 225   // initialization fails, shared spaces [UseSharedSpaces] are
 226   // disabled and the file is closed.
 227   // Map in spaces now also
 228   if (mapinfo->initialize() && map_shared_spaces(mapinfo)) {
 229     size_t cds_total = core_spaces_size();
 230     cds_address = (address)mapinfo->header()->region_addr(0);
 231 #ifdef _LP64
 232     if (Metaspace::using_class_space()) {
 233       char* cds_end = (char*)(cds_address + cds_total);
 234       cds_end = (char *)align_up(cds_end, Metaspace::reserve_alignment());
 235       // If UseCompressedClassPointers is set then allocate the metaspace area
 236       // above the heap and above the CDS area (if it exists).
 237       Metaspace::allocate_metaspace_compressed_klass_ptrs(cds_end, cds_address);
 238       // map_heap_regions() compares the current narrow oop and klass encodings
 239       // with the archived ones, so it must be done after all encodings are determined.
 240       mapinfo->map_heap_regions();
 241     }
 242     Universe::set_narrow_klass_range(CompressedClassSpaceSize);
 243 #endif // _LP64
 244   } else {
 245     assert(!mapinfo->is_open() && !UseSharedSpaces,
 246            "archive file not closed or shared spaces not disabled.");
 247   }
 248 }
 249 
 250 void MetaspaceShared::initialize_dumptime_shared_and_meta_spaces() {
 251   assert(DumpSharedSpaces, "should be called for dump time only");
 252   const size_t reserve_alignment = Metaspace::reserve_alignment();
 253   bool large_pages = false; // No large pages when dumping the CDS archive.
 254   char* shared_base = (char*)align_up((char*)SharedBaseAddress, reserve_alignment);
 255 
 256 #ifdef _LP64
 257   // On 64-bit VM, the heap and class space layout will be the same as if
 258   // you're running in -Xshare:on mode:
 259   //
 260   //                              +-- SharedBaseAddress (default = 0x800000000)
 261   //                              v
 262   // +-..---------+---------+ ... +----+----+----+----+----+---------------+
 263   // |    Heap    | Archive |     | MC | RW | RO | MD | OD | class space   |
 264   // +-..---------+---------+ ... +----+----+----+----+----+---------------+
 265   // |<--   MaxHeapSize  -->|     |<-- UnscaledClassSpaceMax = 4GB ------->|
 266   //
 267   const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
 268   const size_t cds_total = align_down(UnscaledClassSpaceMax, reserve_alignment);
 269 #else
 270   // We don't support archives larger than 256MB on 32-bit due to limited virtual address space.
 271   size_t cds_total = align_down(256*M, reserve_alignment);
 272 #endif
 273 
 274   // First try to reserve the space at the specified SharedBaseAddress.
 275   _shared_rs = ReservedSpace(cds_total, reserve_alignment, large_pages, shared_base);
 276   if (_shared_rs.is_reserved()) {
 277     assert(shared_base == 0 || _shared_rs.base() == shared_base, "should match");
 278   } else {
 279     // Get a mmap region anywhere if the SharedBaseAddress fails.
 280     _shared_rs = ReservedSpace(cds_total, reserve_alignment, large_pages);
 281   }
 282   if (!_shared_rs.is_reserved()) {
 283     vm_exit_during_initialization("Unable to reserve memory for shared space",
 284                                   err_msg(SIZE_FORMAT " bytes.", cds_total));
 285   }
 286 
 287 #ifdef _LP64
 288   // During dump time, we allocate 4GB (UnscaledClassSpaceMax) of space and split it up:
 289   // + The upper 1 GB is used as the "temporary compressed class space" -- preload_classes()
 290   //   will store Klasses into this space.
 291   // + The lower 3 GB is used for the archive -- when preload_classes() is done,
 292   //   ArchiveCompactor will copy the class metadata into this space, first the RW parts,
 293   //   then the RO parts.
 294 
 295   assert(UseCompressedOops && UseCompressedClassPointers,
 296       "UseCompressedOops and UseCompressedClassPointers must be set");
 297 
 298   size_t max_archive_size = align_down(cds_total * 3 / 4, reserve_alignment);
 299   ReservedSpace tmp_class_space = _shared_rs.last_part(max_archive_size);
 300   CompressedClassSpaceSize = align_down(tmp_class_space.size(), reserve_alignment);
 301   _shared_rs = _shared_rs.first_part(max_archive_size);
 302 
 303   // Set up compress class pointers.
 304   Universe::set_narrow_klass_base((address)_shared_rs.base());
 305   // Set narrow_klass_shift to be LogKlassAlignmentInBytes. This is consistent
 306   // with AOT.
 307   Universe::set_narrow_klass_shift(LogKlassAlignmentInBytes);
 308   // Set the range of klass addresses to 4GB.
 309   Universe::set_narrow_klass_range(cds_total);
 310 
 311   Metaspace::initialize_class_space(tmp_class_space);
 312   tty->print_cr("narrow_klass_base = " PTR_FORMAT ", narrow_klass_shift = %d",
 313                 p2i(Universe::narrow_klass_base()), Universe::narrow_klass_shift());
 314 
 315   tty->print_cr("Allocated temporary class space: " SIZE_FORMAT " bytes at " PTR_FORMAT,
 316                 CompressedClassSpaceSize, p2i(tmp_class_space.base()));
 317 #endif
 318 
 319   // Start with 0 committed bytes. The memory will be committed as needed by
 320   // MetaspaceShared::commit_shared_space_to().
 321   if (!_shared_vs.initialize(_shared_rs, 0)) {
 322     vm_exit_during_initialization("Unable to allocate memory for shared space");
 323   }
 324 
 325   _mc_region.init(&_shared_rs);
 326   tty->print_cr("Allocated shared space: " SIZE_FORMAT " bytes at " PTR_FORMAT,
 327                 _shared_rs.size(), p2i(_shared_rs.base()));
 328 }
 329 
 330 // Called by universe_post_init()
 331 void MetaspaceShared::post_initialize(TRAPS) {
 332   if (UseSharedSpaces) {
 333     int size = FileMapInfo::get_number_of_shared_paths();
 334     if (size > 0) {
 335       SystemDictionaryShared::allocate_shared_data_arrays(size, THREAD);
 336       FileMapInfo::FileMapHeader* header = FileMapInfo::current_info()->header();
 337       ClassLoaderExt::init_paths_start_index(header->_app_class_paths_start_index);
 338       ClassLoaderExt::init_app_module_paths_start_index(header->_app_module_paths_start_index);
 339     }
 340   }
 341 
 342   if (DumpSharedSpaces) {
 343     if (SharedArchiveConfigFile) {
 344       read_extra_data(SharedArchiveConfigFile, THREAD);
 345     }
 346   }
 347 }
 348 
 349 void MetaspaceShared::read_extra_data(const char* filename, TRAPS) {
 350   HashtableTextDump reader(filename);
 351   reader.check_version("VERSION: 1.0");
 352 
 353   while (reader.remain() > 0) {
 354     int utf8_length;
 355     int prefix_type = reader.scan_prefix(&utf8_length);
 356     ResourceMark rm(THREAD);
 357     char* utf8_buffer = NEW_RESOURCE_ARRAY(char, utf8_length);
 358     reader.get_utf8(utf8_buffer, utf8_length);
 359 
 360     if (prefix_type == HashtableTextDump::SymbolPrefix) {
 361       SymbolTable::new_symbol(utf8_buffer, utf8_length, THREAD);
 362     } else{
 363       assert(prefix_type == HashtableTextDump::StringPrefix, "Sanity");
 364       utf8_buffer[utf8_length] = '\0';
 365       oop s = StringTable::intern(utf8_buffer, THREAD);
 366     }
 367   }
 368 }
 369 
 370 void MetaspaceShared::commit_shared_space_to(char* newtop) {
 371   assert(DumpSharedSpaces, "dump-time only");
 372   char* base = _shared_rs.base();
 373   size_t need_committed_size = newtop - base;
 374   size_t has_committed_size = _shared_vs.committed_size();
 375   if (need_committed_size < has_committed_size) {
 376     return;
 377   }
 378 
 379   size_t min_bytes = need_committed_size - has_committed_size;
 380   size_t preferred_bytes = 1 * M;
 381   size_t uncommitted = _shared_vs.reserved_size() - has_committed_size;
 382 
 383   size_t commit = MAX2(min_bytes, preferred_bytes);
 384   assert(commit <= uncommitted, "sanity");
 385 
 386   bool result = _shared_vs.expand_by(commit, false);
 387   if (!result) {
 388     vm_exit_during_initialization(err_msg("Failed to expand shared space to " SIZE_FORMAT " bytes",
 389                                           need_committed_size));
 390   }
 391 
 392   log_info(cds)("Expanding shared spaces by " SIZE_FORMAT_W(7) " bytes [total " SIZE_FORMAT_W(9)  " bytes ending at %p]",
 393                 commit, _shared_vs.actual_committed_size(), _shared_vs.high());
 394 }
 395 
 396 // Read/write a data stream for restoring/preserving metadata pointers and
 397 // miscellaneous data from/to the shared archive file.
 398 
 399 void MetaspaceShared::serialize(SerializeClosure* soc) {
 400   int tag = 0;
 401   soc->do_tag(--tag);
 402 
 403   // Verify the sizes of various metadata in the system.
 404   soc->do_tag(sizeof(Method));
 405   soc->do_tag(sizeof(ConstMethod));
 406   soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE));
 407   soc->do_tag(sizeof(ConstantPool));
 408   soc->do_tag(sizeof(ConstantPoolCache));
 409   soc->do_tag(objArrayOopDesc::base_offset_in_bytes());
 410   soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE));
 411   soc->do_tag(sizeof(Symbol));
 412 
 413   // Dump/restore miscellaneous metadata.
 414   Universe::serialize(soc, true);
 415   soc->do_tag(--tag);
 416 
 417   // Dump/restore references to commonly used names and signatures.
 418   vmSymbols::serialize(soc);
 419   soc->do_tag(--tag);
 420 
 421   // Dump/restore the symbol and string tables
 422   SymbolTable::serialize(soc);
 423   StringTable::serialize(soc);
 424   soc->do_tag(--tag);
 425 
 426   JavaClasses::serialize_offsets(soc);
 427   soc->do_tag(--tag);
 428 
 429   soc->do_tag(666);
 430 }
 431 
 432 address MetaspaceShared::cds_i2i_entry_code_buffers(size_t total_size) {
 433   if (DumpSharedSpaces) {
 434     if (_cds_i2i_entry_code_buffers == NULL) {
 435       _cds_i2i_entry_code_buffers = (address)misc_code_space_alloc(total_size);
 436       _cds_i2i_entry_code_buffers_size = total_size;
 437     }
 438   } else if (UseSharedSpaces) {
 439     assert(_cds_i2i_entry_code_buffers != NULL, "must already been initialized");
 440   } else {
 441     return NULL;
 442   }
 443 
 444   assert(_cds_i2i_entry_code_buffers_size == total_size, "must not change");
 445   return _cds_i2i_entry_code_buffers;
 446 }
 447 
 448 // CDS code for dumping shared archive.
 449 
 450 // Global object for holding classes that have been loaded.  Since this
 451 // is run at a safepoint just before exit, this is the entire set of classes.
 452 static GrowableArray<Klass*>* _global_klass_objects;
 453 
 454 static void collect_array_classes(Klass* k) {
 455   _global_klass_objects->append_if_missing(k);
 456   if (k->is_array_klass()) {
 457     // Add in the array classes too
 458     ArrayKlass* ak = ArrayKlass::cast(k);
 459     Klass* h = ak->higher_dimension();
 460     if (h != NULL) {
 461       h->array_klasses_do(collect_array_classes);
 462     }
 463   }
 464 }
 465 
 466 class CollectClassesClosure : public KlassClosure {
 467   void do_klass(Klass* k) {
 468     if (!(k->is_instance_klass() && InstanceKlass::cast(k)->is_in_error_state())) {
 469       if (k->is_instance_klass() && InstanceKlass::cast(k)->signers() != NULL) {
 470         // Mark any class with signers and don't add to the _global_klass_objects
 471         k->set_has_signer_and_not_archived();
 472       } else {
 473         _global_klass_objects->append_if_missing(k);
 474       }
 475     }
 476     if (k->is_array_klass()) {
 477       // Add in the array classes too
 478       ArrayKlass* ak = ArrayKlass::cast(k);
 479       Klass* h = ak->higher_dimension();
 480       if (h != NULL) {
 481         h->array_klasses_do(collect_array_classes);
 482       }
 483     }
 484   }
 485 };
 486 
 487 static void remove_unshareable_in_classes() {
 488   for (int i = 0; i < _global_klass_objects->length(); i++) {
 489     Klass* k = _global_klass_objects->at(i);
 490     if (!k->is_objArray_klass()) {
 491       // InstanceKlass and TypeArrayKlass will in turn call remove_unshareable_info
 492       // on their array classes.
 493       assert(k->is_instance_klass() || k->is_typeArray_klass(), "must be");
 494       k->remove_unshareable_info();
 495     }
 496   }
 497 }
 498 
 499 static void remove_java_mirror_in_classes() {
 500   for (int i = 0; i < _global_klass_objects->length(); i++) {
 501     Klass* k = _global_klass_objects->at(i);
 502     if (!k->is_objArray_klass()) {
 503       // InstanceKlass and TypeArrayKlass will in turn call remove_unshareable_info
 504       // on their array classes.
 505       assert(k->is_instance_klass() || k->is_typeArray_klass(), "must be");
 506       k->remove_java_mirror();
 507     }
 508   }
 509 }
 510 
 511 static void clear_basic_type_mirrors() {
 512   assert(!MetaspaceShared::is_heap_object_archiving_allowed(), "Sanity");
 513   Universe::set_int_mirror(NULL);
 514   Universe::set_float_mirror(NULL);
 515   Universe::set_double_mirror(NULL);
 516   Universe::set_byte_mirror(NULL);
 517   Universe::set_bool_mirror(NULL);
 518   Universe::set_char_mirror(NULL);
 519   Universe::set_long_mirror(NULL);
 520   Universe::set_short_mirror(NULL);
 521   Universe::set_void_mirror(NULL);
 522 }
 523 
 524 static void rewrite_nofast_bytecode(Method* method) {
 525   BytecodeStream bcs(method);
 526   while (!bcs.is_last_bytecode()) {
 527     Bytecodes::Code opcode = bcs.next();
 528     switch (opcode) {
 529     case Bytecodes::_getfield:      *bcs.bcp() = Bytecodes::_nofast_getfield;      break;
 530     case Bytecodes::_putfield:      *bcs.bcp() = Bytecodes::_nofast_putfield;      break;
 531     case Bytecodes::_aload_0:       *bcs.bcp() = Bytecodes::_nofast_aload_0;       break;
 532     case Bytecodes::_iload: {
 533       if (!bcs.is_wide()) {
 534         *bcs.bcp() = Bytecodes::_nofast_iload;
 535       }
 536       break;
 537     }
 538     default: break;
 539     }
 540   }
 541 }
 542 
 543 // Walk all methods in the class list to ensure that they won't be modified at
 544 // run time. This includes:
 545 // [1] Rewrite all bytecodes as needed, so that the ConstMethod* will not be modified
 546 //     at run time by RewriteBytecodes/RewriteFrequentPairs
 547 // [2] Assign a fingerprint, so one doesn't need to be assigned at run-time.
 548 static void rewrite_nofast_bytecodes_and_calculate_fingerprints() {
 549   for (int i = 0; i < _global_klass_objects->length(); i++) {
 550     Klass* k = _global_klass_objects->at(i);
 551     if (k->is_instance_klass()) {
 552       InstanceKlass* ik = InstanceKlass::cast(k);
 553       for (int i = 0; i < ik->methods()->length(); i++) {
 554         Method* m = ik->methods()->at(i);
 555         rewrite_nofast_bytecode(m);
 556         Fingerprinter fp(m);
 557         // The side effect of this call sets method's fingerprint field.
 558         fp.fingerprint();
 559       }
 560     }
 561   }
 562 }
 563 
 564 static void relocate_cached_class_file() {
 565   for (int i = 0; i < _global_klass_objects->length(); i++) {
 566     Klass* k = _global_klass_objects->at(i);
 567     if (k->is_instance_klass()) {
 568       InstanceKlass* ik = InstanceKlass::cast(k);
 569       JvmtiCachedClassFileData* p = ik->get_archived_class_data();
 570       if (p != NULL) {
 571         int size = offset_of(JvmtiCachedClassFileData, data) + p->length;
 572         JvmtiCachedClassFileData* q = (JvmtiCachedClassFileData*)_od_region.allocate(size);
 573         q->length = p->length;
 574         memcpy(q->data, p->data, p->length);
 575         ik->set_archived_class_data(q);
 576       }
 577     }
 578   }
 579 }
 580 
 581 NOT_PRODUCT(
 582 static void assert_not_anonymous_class(InstanceKlass* k) {
 583   assert(!(k->is_anonymous()), "cannot archive anonymous classes");
 584 }
 585 
 586 // Anonymous classes are not stored inside any dictionaries. They are created by
 587 // SystemDictionary::parse_stream() with a non-null host_klass.
 588 static void assert_no_anonymoys_classes_in_dictionaries() {
 589   ClassLoaderDataGraph::dictionary_classes_do(assert_not_anonymous_class);
 590 })
 591 
 592 // Objects of the Metadata types (such as Klass and ConstantPool) have C++ vtables.
 593 // (In GCC this is the field <Type>::_vptr, i.e., first word in the object.)
 594 //
 595 // Addresses of the vtables and the methods may be different across JVM runs,
 596 // if libjvm.so is dynamically loaded at a different base address.
 597 //
 598 // To ensure that the Metadata objects in the CDS archive always have the correct vtable:
 599 //
 600 // + at dump time:  we redirect the _vptr to point to our own vtables inside
 601 //                  the CDS image
 602 // + at run time:   we clone the actual contents of the vtables from libjvm.so
 603 //                  into our own tables.
 604 
 605 // Currently, the archive contain ONLY the following types of objects that have C++ vtables.
 606 #define CPP_VTABLE_PATCH_TYPES_DO(f) \
 607   f(ConstantPool) \
 608   f(InstanceKlass) \
 609   f(InstanceClassLoaderKlass) \
 610   f(InstanceMirrorKlass) \
 611   f(InstanceRefKlass) \
 612   f(Method) \
 613   f(ObjArrayKlass) \
 614   f(TypeArrayKlass)
 615 
 616 class CppVtableInfo {
 617   intptr_t _vtable_size;
 618   intptr_t _cloned_vtable[1];
 619 public:
 620   static int num_slots(int vtable_size) {
 621     return 1 + vtable_size; // Need to add the space occupied by _vtable_size;
 622   }
 623   int vtable_size()           { return int(uintx(_vtable_size)); }
 624   void set_vtable_size(int n) { _vtable_size = intptr_t(n); }
 625   intptr_t* cloned_vtable()   { return &_cloned_vtable[0]; }
 626   void zero()                 { memset(_cloned_vtable, 0, sizeof(intptr_t) * vtable_size()); }
 627   // Returns the address of the next CppVtableInfo that can be placed immediately after this CppVtableInfo
 628   static size_t byte_size(int vtable_size) {
 629     CppVtableInfo i;
 630     return pointer_delta(&i._cloned_vtable[vtable_size], &i, sizeof(u1));
 631   }
 632 };
 633 
 634 template <class T> class CppVtableCloner : public T {
 635   static intptr_t* vtable_of(Metadata& m) {
 636     return *((intptr_t**)&m);
 637   }
 638   static CppVtableInfo* _info;
 639 
 640   static int get_vtable_length(const char* name);
 641 
 642 public:
 643   // Allocate and initialize the C++ vtable, starting from top, but do not go past end.
 644   static intptr_t* allocate(const char* name);
 645 
 646   // Clone the vtable to ...
 647   static intptr_t* clone_vtable(const char* name, CppVtableInfo* info);
 648 
 649   static void zero_vtable_clone() {
 650     assert(DumpSharedSpaces, "dump-time only");
 651     _info->zero();
 652   }
 653 
 654   // Switch the vtable pointer to point to the cloned vtable.
 655   static void patch(Metadata* obj) {
 656     assert(DumpSharedSpaces, "dump-time only");
 657     *(void**)obj = (void*)(_info->cloned_vtable());
 658   }
 659 
 660   static bool is_valid_shared_object(const T* obj) {
 661     intptr_t* vptr = *(intptr_t**)obj;
 662     return vptr == _info->cloned_vtable();
 663   }
 664 };
 665 
 666 template <class T> CppVtableInfo* CppVtableCloner<T>::_info = NULL;
 667 
 668 template <class T>
 669 intptr_t* CppVtableCloner<T>::allocate(const char* name) {
 670   assert(is_aligned(_md_region.top(), sizeof(intptr_t)), "bad alignment");
 671   int n = get_vtable_length(name);
 672   _info = (CppVtableInfo*)_md_region.allocate(CppVtableInfo::byte_size(n), sizeof(intptr_t));
 673   _info->set_vtable_size(n);
 674 
 675   intptr_t* p = clone_vtable(name, _info);
 676   assert((char*)p == _md_region.top(), "must be");
 677 
 678   return p;
 679 }
 680 
 681 template <class T>
 682 intptr_t* CppVtableCloner<T>::clone_vtable(const char* name, CppVtableInfo* info) {
 683   if (!DumpSharedSpaces) {
 684     assert(_info == 0, "_info is initialized only at dump time");
 685     _info = info; // Remember it -- it will be used by MetaspaceShared::is_valid_shared_method()
 686   }
 687   T tmp; // Allocate temporary dummy metadata object to get to the original vtable.
 688   int n = info->vtable_size();
 689   intptr_t* srcvtable = vtable_of(tmp);
 690   intptr_t* dstvtable = info->cloned_vtable();
 691 
 692   // We already checked (and, if necessary, adjusted n) when the vtables were allocated, so we are
 693   // safe to do memcpy.
 694   log_debug(cds, vtables)("Copying %3d vtable entries for %s", n, name);
 695   memcpy(dstvtable, srcvtable, sizeof(intptr_t) * n);
 696   return dstvtable + n;
 697 }
 698 
 699 // To determine the size of the vtable for each type, we use the following
 700 // trick by declaring 2 subclasses:
 701 //
 702 //   class CppVtableTesterA: public InstanceKlass {virtual int   last_virtual_method() {return 1;}    };
 703 //   class CppVtableTesterB: public InstanceKlass {virtual void* last_virtual_method() {return NULL}; };
 704 //
 705 // CppVtableTesterA and CppVtableTesterB's vtables have the following properties:
 706 // - Their size (N+1) is exactly one more than the size of InstanceKlass's vtable (N)
 707 // - The first N entries have are exactly the same as in InstanceKlass's vtable.
 708 // - Their last entry is different.
 709 //
 710 // So to determine the value of N, we just walk CppVtableTesterA and CppVtableTesterB's tables
 711 // and find the first entry that's different.
 712 //
 713 // This works on all C++ compilers supported by Oracle, but you may need to tweak it for more
 714 // esoteric compilers.
 715 
 716 template <class T> class CppVtableTesterB: public T {
 717 public:
 718   virtual int last_virtual_method() {return 1;}
 719 };
 720 
 721 template <class T> class CppVtableTesterA : public T {
 722 public:
 723   virtual void* last_virtual_method() {
 724     // Make this different than CppVtableTesterB::last_virtual_method so the C++
 725     // compiler/linker won't alias the two functions.
 726     return NULL;
 727   }
 728 };
 729 
 730 template <class T>
 731 int CppVtableCloner<T>::get_vtable_length(const char* name) {
 732   CppVtableTesterA<T> a;
 733   CppVtableTesterB<T> b;
 734 
 735   intptr_t* avtable = vtable_of(a);
 736   intptr_t* bvtable = vtable_of(b);
 737 
 738   // Start at slot 1, because slot 0 may be RTTI (on Solaris/Sparc)
 739   int vtable_len = 1;
 740   for (; ; vtable_len++) {
 741     if (avtable[vtable_len] != bvtable[vtable_len]) {
 742       break;
 743     }
 744   }
 745   log_debug(cds, vtables)("Found   %3d vtable entries for %s", vtable_len, name);
 746 
 747   return vtable_len;
 748 }
 749 
 750 #define ALLOC_CPP_VTABLE_CLONE(c) \
 751   CppVtableCloner<c>::allocate(#c);
 752 
 753 #define CLONE_CPP_VTABLE(c) \
 754   p = CppVtableCloner<c>::clone_vtable(#c, (CppVtableInfo*)p);
 755 
 756 #define ZERO_CPP_VTABLE(c) \
 757  CppVtableCloner<c>::zero_vtable_clone();
 758 
 759 // This can be called at both dump time and run time.
 760 intptr_t* MetaspaceShared::clone_cpp_vtables(intptr_t* p) {
 761   assert(DumpSharedSpaces || UseSharedSpaces, "sanity");
 762   CPP_VTABLE_PATCH_TYPES_DO(CLONE_CPP_VTABLE);
 763   return p;
 764 }
 765 
 766 void MetaspaceShared::zero_cpp_vtable_clones_for_writing() {
 767   assert(DumpSharedSpaces, "dump-time only");
 768   CPP_VTABLE_PATCH_TYPES_DO(ZERO_CPP_VTABLE);
 769 }
 770 
 771 // Allocate and initialize the C++ vtables, starting from top, but do not go past end.
 772 void MetaspaceShared::allocate_cpp_vtable_clones() {
 773   assert(DumpSharedSpaces, "dump-time only");
 774   // Layout (each slot is a intptr_t):
 775   //   [number of slots in the first vtable = n1]
 776   //   [ <n1> slots for the first vtable]
 777   //   [number of slots in the first second = n2]
 778   //   [ <n2> slots for the second vtable]
 779   //   ...
 780   // The order of the vtables is the same as the CPP_VTAB_PATCH_TYPES_DO macro.
 781   CPP_VTABLE_PATCH_TYPES_DO(ALLOC_CPP_VTABLE_CLONE);
 782 }
 783 
 784 // Switch the vtable pointer to point to the cloned vtable. We assume the
 785 // vtable pointer is in first slot in object.
 786 void MetaspaceShared::patch_cpp_vtable_pointers() {
 787   int n = _global_klass_objects->length();
 788   for (int i = 0; i < n; i++) {
 789     Klass* obj = _global_klass_objects->at(i);
 790     if (obj->is_instance_klass()) {
 791       InstanceKlass* ik = InstanceKlass::cast(obj);
 792       if (ik->is_class_loader_instance_klass()) {
 793         CppVtableCloner<InstanceClassLoaderKlass>::patch(ik);
 794       } else if (ik->is_reference_instance_klass()) {
 795         CppVtableCloner<InstanceRefKlass>::patch(ik);
 796       } else if (ik->is_mirror_instance_klass()) {
 797         CppVtableCloner<InstanceMirrorKlass>::patch(ik);
 798       } else {
 799         CppVtableCloner<InstanceKlass>::patch(ik);
 800       }
 801       ConstantPool* cp = ik->constants();
 802       CppVtableCloner<ConstantPool>::patch(cp);
 803       for (int j = 0; j < ik->methods()->length(); j++) {
 804         Method* m = ik->methods()->at(j);
 805         CppVtableCloner<Method>::patch(m);
 806         assert(CppVtableCloner<Method>::is_valid_shared_object(m), "must be");
 807       }
 808     } else if (obj->is_objArray_klass()) {
 809       CppVtableCloner<ObjArrayKlass>::patch(obj);
 810     } else {
 811       assert(obj->is_typeArray_klass(), "sanity");
 812       CppVtableCloner<TypeArrayKlass>::patch(obj);
 813     }
 814   }
 815 }
 816 
 817 bool MetaspaceShared::is_valid_shared_method(const Method* m) {
 818   assert(is_in_shared_metaspace(m), "must be");
 819   return CppVtableCloner<Method>::is_valid_shared_object(m);
 820 }
 821 
 822 // Closure for serializing initialization data out to a data area to be
 823 // written to the shared file.
 824 
 825 class WriteClosure : public SerializeClosure {
 826 private:
 827   DumpRegion* _dump_region;
 828 
 829 public:
 830   WriteClosure(DumpRegion* r) {
 831     _dump_region = r;
 832   }
 833 
 834   void do_ptr(void** p) {
 835     _dump_region->append_intptr_t((intptr_t)*p);
 836   }
 837 
 838   void do_u4(u4* p) {
 839     void* ptr = (void*)(uintx(*p));
 840     do_ptr(&ptr);
 841   }
 842 
 843   void do_tag(int tag) {
 844     _dump_region->append_intptr_t((intptr_t)tag);
 845   }
 846 
 847   void do_oop(oop* o) {
 848     if (*o == NULL) {
 849       _dump_region->append_intptr_t(0);
 850     } else {
 851       assert(MetaspaceShared::is_heap_object_archiving_allowed(),
 852              "Archiving heap object is not allowed");
 853       _dump_region->append_intptr_t(
 854         (intptr_t)CompressedOops::encode_not_null(*o));
 855     }
 856   }
 857 
 858   void do_region(u_char* start, size_t size) {
 859     assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment");
 860     assert(size % sizeof(intptr_t) == 0, "bad size");
 861     do_tag((int)size);
 862     while (size > 0) {
 863       _dump_region->append_intptr_t(*(intptr_t*)start);
 864       start += sizeof(intptr_t);
 865       size -= sizeof(intptr_t);
 866     }
 867   }
 868 
 869   bool reading() const { return false; }
 870 };
 871 
 872 // This is for dumping detailed statistics for the allocations
 873 // in the shared spaces.
 874 class DumpAllocStats : public ResourceObj {
 875 public:
 876 
 877   // Here's poor man's enum inheritance
 878 #define SHAREDSPACE_OBJ_TYPES_DO(f) \
 879   METASPACE_OBJ_TYPES_DO(f) \
 880   f(SymbolHashentry) \
 881   f(SymbolBucket) \
 882   f(StringHashentry) \
 883   f(StringBucket) \
 884   f(Other)
 885 
 886   enum Type {
 887     // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc
 888     SHAREDSPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE)
 889     _number_of_types
 890   };
 891 
 892   static const char * type_name(Type type) {
 893     switch(type) {
 894     SHAREDSPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE)
 895     default:
 896       ShouldNotReachHere();
 897       return NULL;
 898     }
 899   }
 900 
 901 public:
 902   enum { RO = 0, RW = 1 };
 903 
 904   int _counts[2][_number_of_types];
 905   int _bytes [2][_number_of_types];
 906 
 907   DumpAllocStats() {
 908     memset(_counts, 0, sizeof(_counts));
 909     memset(_bytes,  0, sizeof(_bytes));
 910   };
 911 
 912   void record(MetaspaceObj::Type type, int byte_size, bool read_only) {
 913     assert(int(type) >= 0 && type < MetaspaceObj::_number_of_types, "sanity");
 914     int which = (read_only) ? RO : RW;
 915     _counts[which][type] ++;
 916     _bytes [which][type] += byte_size;
 917   }
 918 
 919   void record_other_type(int byte_size, bool read_only) {
 920     int which = (read_only) ? RO : RW;
 921     _bytes [which][OtherType] += byte_size;
 922   }
 923   void print_stats(int ro_all, int rw_all, int mc_all, int md_all);
 924 };
 925 
 926 void DumpAllocStats::print_stats(int ro_all, int rw_all, int mc_all, int md_all) {
 927   // Calculate size of data that was not allocated by Metaspace::allocate()
 928   MetaspaceSharedStats *stats = MetaspaceShared::stats();
 929 
 930   // symbols
 931   _counts[RO][SymbolHashentryType] = stats->symbol.hashentry_count;
 932   _bytes [RO][SymbolHashentryType] = stats->symbol.hashentry_bytes;
 933 
 934   _counts[RO][SymbolBucketType] = stats->symbol.bucket_count;
 935   _bytes [RO][SymbolBucketType] = stats->symbol.bucket_bytes;
 936 
 937   // strings
 938   _counts[RO][StringHashentryType] = stats->string.hashentry_count;
 939   _bytes [RO][StringHashentryType] = stats->string.hashentry_bytes;
 940 
 941   _counts[RO][StringBucketType] = stats->string.bucket_count;
 942   _bytes [RO][StringBucketType] = stats->string.bucket_bytes;
 943 
 944   // TODO: count things like dictionary, vtable, etc
 945   _bytes[RW][OtherType] += mc_all + md_all;
 946   rw_all += mc_all + md_all; // mc/md are mapped Read/Write
 947 
 948   // prevent divide-by-zero
 949   if (ro_all < 1) {
 950     ro_all = 1;
 951   }
 952   if (rw_all < 1) {
 953     rw_all = 1;
 954   }
 955 
 956   int all_ro_count = 0;
 957   int all_ro_bytes = 0;
 958   int all_rw_count = 0;
 959   int all_rw_bytes = 0;
 960 
 961 // To make fmt_stats be a syntactic constant (for format warnings), use #define.
 962 #define fmt_stats "%-20s: %8d %10d %5.1f | %8d %10d %5.1f | %8d %10d %5.1f"
 963   const char *sep = "--------------------+---------------------------+---------------------------+--------------------------";
 964   const char *hdr = "                        ro_cnt   ro_bytes     % |   rw_cnt   rw_bytes     % |  all_cnt  all_bytes     %";
 965 
 966   LogMessage(cds) msg;
 967 
 968   msg.info("Detailed metadata info (excluding od/st regions; rw stats include md/mc regions):");
 969   msg.info("%s", hdr);
 970   msg.info("%s", sep);
 971   for (int type = 0; type < int(_number_of_types); type ++) {
 972     const char *name = type_name((Type)type);
 973     int ro_count = _counts[RO][type];
 974     int ro_bytes = _bytes [RO][type];
 975     int rw_count = _counts[RW][type];
 976     int rw_bytes = _bytes [RW][type];
 977     int count = ro_count + rw_count;
 978     int bytes = ro_bytes + rw_bytes;
 979 
 980     double ro_perc = percent_of(ro_bytes, ro_all);
 981     double rw_perc = percent_of(rw_bytes, rw_all);
 982     double perc    = percent_of(bytes, ro_all + rw_all);
 983 
 984     msg.info(fmt_stats, name,
 985                          ro_count, ro_bytes, ro_perc,
 986                          rw_count, rw_bytes, rw_perc,
 987                          count, bytes, perc);
 988 
 989     all_ro_count += ro_count;
 990     all_ro_bytes += ro_bytes;
 991     all_rw_count += rw_count;
 992     all_rw_bytes += rw_bytes;
 993   }
 994 
 995   int all_count = all_ro_count + all_rw_count;
 996   int all_bytes = all_ro_bytes + all_rw_bytes;
 997 
 998   double all_ro_perc = percent_of(all_ro_bytes, ro_all);
 999   double all_rw_perc = percent_of(all_rw_bytes, rw_all);
1000   double all_perc    = percent_of(all_bytes, ro_all + rw_all);
1001 
1002   msg.info("%s", sep);
1003   msg.info(fmt_stats, "Total",
1004                        all_ro_count, all_ro_bytes, all_ro_perc,
1005                        all_rw_count, all_rw_bytes, all_rw_perc,
1006                        all_count, all_bytes, all_perc);
1007 
1008   assert(all_ro_bytes == ro_all, "everything should have been counted");
1009   assert(all_rw_bytes == rw_all, "everything should have been counted");
1010 
1011 #undef fmt_stats
1012 }
1013 
1014 // Populate the shared space.
1015 
1016 class VM_PopulateDumpSharedSpace: public VM_Operation {
1017 private:
1018   GrowableArray<MemRegion> *_closed_archive_heap_regions;
1019   GrowableArray<MemRegion> *_open_archive_heap_regions;
1020 
1021   void dump_java_heap_objects() NOT_CDS_JAVA_HEAP_RETURN;
1022   void dump_symbols();
1023   char* dump_read_only_tables();
1024   void print_region_stats();
1025   void print_heap_region_stats(GrowableArray<MemRegion> *heap_mem,
1026                                const char *name, const size_t total_size);
1027 public:
1028 
1029   VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
1030   void doit();   // outline because gdb sucks
1031   static void write_region(FileMapInfo* mapinfo, int region, DumpRegion* space, bool read_only,  bool allow_exec);
1032   bool allow_nested_vm_operations() const { return true; }
1033 }; // class VM_PopulateDumpSharedSpace
1034 
1035 class SortedSymbolClosure: public SymbolClosure {
1036   GrowableArray<Symbol*> _symbols;
1037   virtual void do_symbol(Symbol** sym) {
1038     assert((*sym)->is_permanent(), "archived symbols must be permanent");
1039     _symbols.append(*sym);
1040   }
1041   static int compare_symbols_by_address(Symbol** a, Symbol** b) {
1042     if (a[0] < b[0]) {
1043       return -1;
1044     } else if (a[0] == b[0]) {
1045       return 0;
1046     } else {
1047       return 1;
1048     }
1049   }
1050 
1051 public:
1052   SortedSymbolClosure() {
1053     SymbolTable::symbols_do(this);
1054     _symbols.sort(compare_symbols_by_address);
1055   }
1056   GrowableArray<Symbol*>* get_sorted_symbols() {
1057     return &_symbols;
1058   }
1059 };
1060 
1061 // ArchiveCompactor --
1062 //
1063 // This class is the central piece of shared archive compaction -- all metaspace data are
1064 // initially allocated outside of the shared regions. ArchiveCompactor copies the
1065 // metaspace data into their final location in the shared regions.
1066 
1067 class ArchiveCompactor : AllStatic {
1068   static DumpAllocStats* _alloc_stats;
1069   static SortedSymbolClosure* _ssc;
1070 
1071   static unsigned my_hash(const address& a) {
1072     return primitive_hash<address>(a);
1073   }
1074   static bool my_equals(const address& a0, const address& a1) {
1075     return primitive_equals<address>(a0, a1);
1076   }
1077   typedef ResourceHashtable<
1078       address, address,
1079       ArchiveCompactor::my_hash,   // solaris compiler doesn't like: primitive_hash<address>
1080       ArchiveCompactor::my_equals, // solaris compiler doesn't like: primitive_equals<address>
1081       16384, ResourceObj::C_HEAP> RelocationTable;
1082   static RelocationTable* _new_loc_table;
1083 
1084 public:
1085   static void initialize() {
1086     _alloc_stats = new(ResourceObj::C_HEAP, mtInternal)DumpAllocStats;
1087     _new_loc_table = new(ResourceObj::C_HEAP, mtInternal)RelocationTable;
1088   }
1089   static DumpAllocStats* alloc_stats() {
1090     return _alloc_stats;
1091   }
1092 
1093   static void allocate(MetaspaceClosure::Ref* ref, bool read_only) {
1094     address obj = ref->obj();
1095     int bytes = ref->size() * BytesPerWord;
1096     char* p;
1097     size_t alignment = BytesPerWord;
1098     char* oldtop;
1099     char* newtop;
1100 
1101     if (read_only) {
1102       oldtop = _ro_region.top();
1103       p = _ro_region.allocate(bytes, alignment);
1104       newtop = _ro_region.top();
1105     } else {
1106       oldtop = _rw_region.top();
1107       p = _rw_region.allocate(bytes, alignment);
1108       newtop = _rw_region.top();
1109     }
1110     memcpy(p, obj, bytes);
1111     bool isnew = _new_loc_table->put(obj, (address)p);
1112     log_trace(cds)("Copy: " PTR_FORMAT " ==> " PTR_FORMAT " %d", p2i(obj), p2i(p), bytes);
1113     assert(isnew, "must be");
1114 
1115     _alloc_stats->record(ref->msotype(), int(newtop - oldtop), read_only);
1116     if (ref->msotype() == MetaspaceObj::SymbolType) {
1117       uintx delta = MetaspaceShared::object_delta(p);
1118       if (delta > MAX_SHARED_DELTA) {
1119         // This is just a sanity check and should not appear in any real world usage. This
1120         // happens only if you allocate more than 2GB of Symbols and would require
1121         // millions of shared classes.
1122         vm_exit_during_initialization("Too many Symbols in the CDS archive",
1123                                       "Please reduce the number of shared classes.");
1124       }
1125     }
1126   }
1127 
1128   static address get_new_loc(MetaspaceClosure::Ref* ref) {
1129     address* pp = _new_loc_table->get(ref->obj());
1130     assert(pp != NULL, "must be");
1131     return *pp;
1132   }
1133 
1134 private:
1135   // Makes a shallow copy of visited MetaspaceObj's
1136   class ShallowCopier: public UniqueMetaspaceClosure {
1137     bool _read_only;
1138   public:
1139     ShallowCopier(bool read_only) : _read_only(read_only) {}
1140 
1141     virtual void do_unique_ref(Ref* ref, bool read_only) {
1142       if (read_only == _read_only) {
1143         allocate(ref, read_only);
1144       }
1145     }
1146   };
1147 
1148   // Relocate embedded pointers within a MetaspaceObj's shallow copy
1149   class ShallowCopyEmbeddedRefRelocator: public UniqueMetaspaceClosure {
1150   public:
1151     virtual void do_unique_ref(Ref* ref, bool read_only) {
1152       address new_loc = get_new_loc(ref);
1153       RefRelocator refer;
1154       ref->metaspace_pointers_do_at(&refer, new_loc);
1155     }
1156   };
1157 
1158   // Relocate a reference to point to its shallow copy
1159   class RefRelocator: public MetaspaceClosure {
1160   public:
1161     virtual bool do_ref(Ref* ref, bool read_only) {
1162       if (ref->not_null()) {
1163         ref->update(get_new_loc(ref));
1164       }
1165       return false; // Do not recurse.
1166     }
1167   };
1168 
1169 #ifdef ASSERT
1170   class IsRefInArchiveChecker: public MetaspaceClosure {
1171   public:
1172     virtual bool do_ref(Ref* ref, bool read_only) {
1173       if (ref->not_null()) {
1174         char* obj = (char*)ref->obj();
1175         assert(_ro_region.contains(obj) || _rw_region.contains(obj),
1176                "must be relocated to point to CDS archive");
1177       }
1178       return false; // Do not recurse.
1179     }
1180   };
1181 #endif
1182 
1183 public:
1184   static void copy_and_compact() {
1185     // We should no longer allocate anything from the metaspace, so that
1186     // we can have a stable set of MetaspaceObjs to work with.
1187     Metaspace::freeze();
1188 
1189     ResourceMark rm;
1190     SortedSymbolClosure the_ssc; // StackObj
1191     _ssc = &the_ssc;
1192 
1193     tty->print_cr("Scanning all metaspace objects ... ");
1194     {
1195       // allocate and shallow-copy RW objects, immediately following the MC region
1196       tty->print_cr("Allocating RW objects ... ");
1197       _mc_region.pack(&_rw_region);
1198 
1199       ResourceMark rm;
1200       ShallowCopier rw_copier(false);
1201       iterate_roots(&rw_copier);
1202     }
1203     {
1204       // allocate and shallow-copy of RO object, immediately following the RW region
1205       tty->print_cr("Allocating RO objects ... ");
1206       _rw_region.pack(&_ro_region);
1207 
1208       ResourceMark rm;
1209       ShallowCopier ro_copier(true);
1210       iterate_roots(&ro_copier);
1211     }
1212     {
1213       tty->print_cr("Relocating embedded pointers ... ");
1214       ResourceMark rm;
1215       ShallowCopyEmbeddedRefRelocator emb_reloc;
1216       iterate_roots(&emb_reloc);
1217     }
1218     {
1219       tty->print_cr("Relocating external roots ... ");
1220       ResourceMark rm;
1221       RefRelocator ext_reloc;
1222       iterate_roots(&ext_reloc);
1223     }
1224 
1225 #ifdef ASSERT
1226     {
1227       tty->print_cr("Verifying external roots ... ");
1228       ResourceMark rm;
1229       IsRefInArchiveChecker checker;
1230       iterate_roots(&checker);
1231     }
1232 #endif
1233 
1234 
1235     // cleanup
1236     _ssc = NULL;
1237   }
1238 
1239   // We must relocate the System::_well_known_klasses only after we have copied the
1240   // java objects in during dump_java_heap_objects(): during the object copy, we operate on
1241   // old objects which assert that their klass is the original klass.
1242   static void relocate_well_known_klasses() {
1243     {
1244       tty->print_cr("Relocating SystemDictionary::_well_known_klasses[] ... ");
1245       ResourceMark rm;
1246       RefRelocator ext_reloc;
1247       SystemDictionary::well_known_klasses_do(&ext_reloc);
1248     }
1249     // NOTE: after this point, we shouldn't have any globals that can reach the old
1250     // objects.
1251 
1252     // We cannot use any of the objects in the heap anymore (except for the objects
1253     // in the CDS shared string regions) because their headers no longer point to
1254     // valid Klasses.
1255   }
1256 
1257   static void iterate_roots(MetaspaceClosure* it) {
1258     GrowableArray<Symbol*>* symbols = _ssc->get_sorted_symbols();
1259     for (int i=0; i<symbols->length(); i++) {
1260       it->push(symbols->adr_at(i));
1261     }
1262     if (_global_klass_objects != NULL) {
1263       // Need to fix up the pointers
1264       for (int i = 0; i < _global_klass_objects->length(); i++) {
1265         // NOTE -- this requires that the vtable is NOT yet patched, or else we are hosed.
1266         it->push(_global_klass_objects->adr_at(i));
1267       }
1268     }
1269     FileMapInfo::metaspace_pointers_do(it);
1270     SystemDictionary::classes_do(it);
1271     Universe::metaspace_pointers_do(it);
1272     SymbolTable::metaspace_pointers_do(it);
1273     vmSymbols::metaspace_pointers_do(it);
1274   }
1275 
1276   static Klass* get_relocated_klass(Klass* orig_klass) {
1277     assert(DumpSharedSpaces, "dump time only");
1278     address* pp = _new_loc_table->get((address)orig_klass);
1279     assert(pp != NULL, "must be");
1280     Klass* klass = (Klass*)(*pp);
1281     assert(klass->is_klass(), "must be");
1282     return klass;
1283   }
1284 };
1285 
1286 DumpAllocStats* ArchiveCompactor::_alloc_stats;
1287 SortedSymbolClosure* ArchiveCompactor::_ssc;
1288 ArchiveCompactor::RelocationTable* ArchiveCompactor::_new_loc_table;
1289 
1290 void VM_PopulateDumpSharedSpace::write_region(FileMapInfo* mapinfo, int region_idx,
1291                                               DumpRegion* dump_region, bool read_only,  bool allow_exec) {
1292   mapinfo->write_region(region_idx, dump_region->base(), dump_region->used(), read_only, allow_exec);
1293 }
1294 
1295 void VM_PopulateDumpSharedSpace::dump_symbols() {
1296   tty->print_cr("Dumping symbol table ...");
1297 
1298   NOT_PRODUCT(SymbolTable::verify());
1299   SymbolTable::write_to_archive();
1300 }
1301 
1302 char* VM_PopulateDumpSharedSpace::dump_read_only_tables() {
1303   char* oldtop = _ro_region.top();
1304   // Reorder the system dictionary. Moving the symbols affects
1305   // how the hash table indices are calculated.
1306   SystemDictionary::reorder_dictionary_for_sharing();
1307 
1308   tty->print("Removing java_mirror ... ");
1309   if (!MetaspaceShared::is_heap_object_archiving_allowed()) {
1310     clear_basic_type_mirrors();
1311   }
1312   remove_java_mirror_in_classes();
1313   tty->print_cr("done. ");
1314   NOT_PRODUCT(SystemDictionary::verify();)
1315 
1316   size_t buckets_bytes = SystemDictionary::count_bytes_for_buckets();
1317   char* buckets_top = _ro_region.allocate(buckets_bytes, sizeof(intptr_t));
1318   SystemDictionary::copy_buckets(buckets_top, _ro_region.top());
1319 
1320   size_t table_bytes = SystemDictionary::count_bytes_for_table();
1321   char* table_top = _ro_region.allocate(table_bytes, sizeof(intptr_t));
1322   SystemDictionary::copy_table(table_top, _ro_region.top());
1323 
1324   // Write the archived object sub-graph infos. For each klass with sub-graphs,
1325   // the info includes the static fields (sub-graph entry points) and Klasses
1326   // of objects included in the sub-graph.
1327   HeapShared::write_archived_subgraph_infos();
1328 
1329   // Write the other data to the output array.
1330   WriteClosure wc(&_ro_region);
1331   MetaspaceShared::serialize(&wc);
1332 
1333   char* newtop = _ro_region.top();
1334   ArchiveCompactor::alloc_stats()->record_other_type(int(newtop - oldtop), true);
1335   return buckets_top;
1336 }
1337 
1338 void VM_PopulateDumpSharedSpace::doit() {
1339   Thread* THREAD = VMThread::vm_thread();
1340 
1341   FileMapInfo::check_nonempty_dir_in_shared_path_table();
1342 
1343   NOT_PRODUCT(SystemDictionary::verify();)
1344   // The following guarantee is meant to ensure that no loader constraints
1345   // exist yet, since the constraints table is not shared.  This becomes
1346   // more important now that we don't re-initialize vtables/itables for
1347   // shared classes at runtime, where constraints were previously created.
1348   guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
1349             "loader constraints are not saved");
1350   guarantee(SystemDictionary::placeholders()->number_of_entries() == 0,
1351           "placeholders are not saved");
1352   // Revisit and implement this if we prelink method handle call sites:
1353   guarantee(SystemDictionary::invoke_method_table() == NULL ||
1354             SystemDictionary::invoke_method_table()->number_of_entries() == 0,
1355             "invoke method table is not saved");
1356 
1357   // At this point, many classes have been loaded.
1358   // Gather systemDictionary classes in a global array and do everything to
1359   // that so we don't have to walk the SystemDictionary again.
1360   _global_klass_objects = new GrowableArray<Klass*>(1000);
1361   CollectClassesClosure collect_classes;
1362   ClassLoaderDataGraph::loaded_classes_do(&collect_classes);
1363 
1364   tty->print_cr("Number of classes %d", _global_klass_objects->length());
1365   {
1366     int num_type_array = 0, num_obj_array = 0, num_inst = 0;
1367     for (int i = 0; i < _global_klass_objects->length(); i++) {
1368       Klass* k = _global_klass_objects->at(i);
1369       if (k->is_instance_klass()) {
1370         num_inst ++;
1371       } else if (k->is_objArray_klass()) {
1372         num_obj_array ++;
1373       } else {
1374         assert(k->is_typeArray_klass(), "sanity");
1375         num_type_array ++;
1376       }
1377     }
1378     tty->print_cr("    instance classes   = %5d", num_inst);
1379     tty->print_cr("    obj array classes  = %5d", num_obj_array);
1380     tty->print_cr("    type array classes = %5d", num_type_array);
1381   }
1382 
1383   // Ensure the ConstMethods won't be modified at run-time
1384   tty->print("Updating ConstMethods ... ");
1385   rewrite_nofast_bytecodes_and_calculate_fingerprints();
1386   tty->print_cr("done. ");
1387 
1388   // Move classes from platform/system dictionaries into the boot dictionary
1389   SystemDictionary::combine_shared_dictionaries();
1390 
1391   // Make sure all classes have a correct loader type.
1392   ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(MetaspaceShared::check_shared_class_loader_type);
1393 
1394   // Remove all references outside the metadata
1395   tty->print("Removing unshareable information ... ");
1396   remove_unshareable_in_classes();
1397   tty->print_cr("done. ");
1398 
1399   // We don't support archiving anonymous classes. Verify that they are not stored in
1400   // the any dictionaries.
1401   NOT_PRODUCT(assert_no_anonymoys_classes_in_dictionaries());
1402 
1403   SystemDictionaryShared::finalize_verification_constraints();
1404 
1405   ArchiveCompactor::initialize();
1406   ArchiveCompactor::copy_and_compact();
1407 
1408   dump_symbols();
1409 
1410   // Dump supported java heap objects
1411   _closed_archive_heap_regions = NULL;
1412   _open_archive_heap_regions = NULL;
1413   dump_java_heap_objects();
1414 
1415   ArchiveCompactor::relocate_well_known_klasses();
1416 
1417   char* read_only_tables_start = dump_read_only_tables();
1418   _ro_region.pack(&_md_region);
1419 
1420   char* vtbl_list = _md_region.top();
1421   MetaspaceShared::allocate_cpp_vtable_clones();
1422   _md_region.pack(&_od_region);
1423 
1424   // Relocate the archived class file data into the od region
1425   relocate_cached_class_file();
1426   _od_region.pack();
1427 
1428   // The 5 core spaces are allocated consecutively mc->rw->ro->md->od, so there total size
1429   // is just the spaces between the two ends.
1430   size_t core_spaces_size = _od_region.end() - _mc_region.base();
1431   assert(core_spaces_size == (size_t)align_up(core_spaces_size, Metaspace::reserve_alignment()),
1432          "should already be aligned");
1433 
1434   // During patching, some virtual methods may be called, so at this point
1435   // the vtables must contain valid methods (as filled in by CppVtableCloner::allocate).
1436   MetaspaceShared::patch_cpp_vtable_pointers();
1437 
1438   // The vtable clones contain addresses of the current process.
1439   // We don't want to write these addresses into the archive.
1440   MetaspaceShared::zero_cpp_vtable_clones_for_writing();
1441 
1442   // Create and write the archive file that maps the shared spaces.
1443 
1444   FileMapInfo* mapinfo = new FileMapInfo();
1445   mapinfo->populate_header(os::vm_allocation_granularity());
1446   mapinfo->set_read_only_tables_start(read_only_tables_start);
1447   mapinfo->set_misc_data_patching_start(vtbl_list);
1448   mapinfo->set_cds_i2i_entry_code_buffers(MetaspaceShared::cds_i2i_entry_code_buffers());
1449   mapinfo->set_cds_i2i_entry_code_buffers_size(MetaspaceShared::cds_i2i_entry_code_buffers_size());
1450   mapinfo->set_core_spaces_size(core_spaces_size);
1451 
1452   for (int pass=1; pass<=2; pass++) {
1453     if (pass == 1) {
1454       // The first pass doesn't actually write the data to disk. All it
1455       // does is to update the fields in the mapinfo->_header.
1456     } else {
1457       // After the first pass, the contents of mapinfo->_header are finalized,
1458       // so we can compute the header's CRC, and write the contents of the header
1459       // and the regions into disk.
1460       mapinfo->open_for_write();
1461       mapinfo->set_header_crc(mapinfo->compute_header_crc());
1462     }
1463     mapinfo->write_header();
1464 
1465     // NOTE: md contains the trampoline code for method entries, which are patched at run time,
1466     // so it needs to be read/write.
1467     write_region(mapinfo, MetaspaceShared::mc, &_mc_region, /*read_only=*/false,/*allow_exec=*/true);
1468     write_region(mapinfo, MetaspaceShared::rw, &_rw_region, /*read_only=*/false,/*allow_exec=*/false);
1469     write_region(mapinfo, MetaspaceShared::ro, &_ro_region, /*read_only=*/true, /*allow_exec=*/false);
1470     write_region(mapinfo, MetaspaceShared::md, &_md_region, /*read_only=*/false,/*allow_exec=*/false);
1471     write_region(mapinfo, MetaspaceShared::od, &_od_region, /*read_only=*/true, /*allow_exec=*/false);
1472 
1473     _total_string_region_size = mapinfo->write_archive_heap_regions(
1474                                         _closed_archive_heap_regions,
1475                                         MetaspaceShared::first_string,
1476                                         MetaspaceShared::max_strings);
1477     _total_open_archive_region_size = mapinfo->write_archive_heap_regions(
1478                                         _open_archive_heap_regions,
1479                                         MetaspaceShared::first_open_archive_heap_region,
1480                                         MetaspaceShared::max_open_archive_heap_region);
1481   }
1482 
1483   mapinfo->close();
1484 
1485   // Restore the vtable in case we invoke any virtual methods.
1486   MetaspaceShared::clone_cpp_vtables((intptr_t*)vtbl_list);
1487 
1488   print_region_stats();
1489 
1490   if (log_is_enabled(Info, cds)) {
1491     ArchiveCompactor::alloc_stats()->print_stats(int(_ro_region.used()), int(_rw_region.used()),
1492                                                  int(_mc_region.used()), int(_md_region.used()));
1493   }
1494 
1495   if (PrintSystemDictionaryAtExit) {
1496     SystemDictionary::print();
1497   }
1498   // There may be other pending VM operations that operate on the InstanceKlasses,
1499   // which will fail because InstanceKlasses::remove_unshareable_info()
1500   // has been called. Forget these operations and exit the VM directly.
1501   vm_direct_exit(0);
1502 }
1503 
1504 void VM_PopulateDumpSharedSpace::print_region_stats() {
1505   // Print statistics of all the regions
1506   const size_t total_reserved = _ro_region.reserved()  + _rw_region.reserved() +
1507                                 _mc_region.reserved()  + _md_region.reserved() +
1508                                 _od_region.reserved()  +
1509                                 _total_string_region_size +
1510                                 _total_open_archive_region_size;
1511   const size_t total_bytes = _ro_region.used()  + _rw_region.used() +
1512                              _mc_region.used()  + _md_region.used() +
1513                              _od_region.used()  +
1514                              _total_string_region_size +
1515                              _total_open_archive_region_size;
1516   const double total_u_perc = percent_of(total_bytes, total_reserved);
1517 
1518   _mc_region.print(total_reserved);
1519   _rw_region.print(total_reserved);
1520   _ro_region.print(total_reserved);
1521   _md_region.print(total_reserved);
1522   _od_region.print(total_reserved);
1523   print_heap_region_stats(_closed_archive_heap_regions, "st", total_reserved);
1524   print_heap_region_stats(_open_archive_heap_regions, "oa", total_reserved);
1525 
1526   tty->print_cr("total    : " SIZE_FORMAT_W(9) " [100.0%% of total] out of " SIZE_FORMAT_W(9) " bytes [%5.1f%% used]",
1527                  total_bytes, total_reserved, total_u_perc);
1528 }
1529 
1530 void VM_PopulateDumpSharedSpace::print_heap_region_stats(GrowableArray<MemRegion> *heap_mem,
1531                                                          const char *name, const size_t total_size) {
1532   int arr_len = heap_mem == NULL ? 0 : heap_mem->length();
1533   for (int i = 0; i < arr_len; i++) {
1534       char* start = (char*)heap_mem->at(i).start();
1535       size_t size = heap_mem->at(i).byte_size();
1536       char* top = start + size;
1537       tty->print_cr("%s%d space: " SIZE_FORMAT_W(9) " [ %4.1f%% of total] out of " SIZE_FORMAT_W(9) " bytes [100.0%% used] at " INTPTR_FORMAT,
1538                     name, i, size, size/double(total_size)*100.0, size, p2i(start));
1539 
1540   }
1541 }
1542 
1543 // Update a Java object to point its Klass* to the new location after
1544 // shared archive has been compacted.
1545 void MetaspaceShared::relocate_klass_ptr(oop o) {
1546   assert(DumpSharedSpaces, "sanity");
1547   Klass* k = ArchiveCompactor::get_relocated_klass(o->klass());
1548   o->set_klass(k);
1549 }
1550 
1551 Klass* MetaspaceShared::get_relocated_klass(Klass *k) {
1552   assert(DumpSharedSpaces, "sanity");
1553   return ArchiveCompactor::get_relocated_klass(k);
1554 }
1555 
1556 class LinkSharedClassesClosure : public KlassClosure {
1557   Thread* THREAD;
1558   bool    _made_progress;
1559  public:
1560   LinkSharedClassesClosure(Thread* thread) : THREAD(thread), _made_progress(false) {}
1561 
1562   void reset()               { _made_progress = false; }
1563   bool made_progress() const { return _made_progress; }
1564 
1565   void do_klass(Klass* k) {
1566     if (k->is_instance_klass()) {
1567       InstanceKlass* ik = InstanceKlass::cast(k);
1568       // Link the class to cause the bytecodes to be rewritten and the
1569       // cpcache to be created. Class verification is done according
1570       // to -Xverify setting.
1571       _made_progress |= MetaspaceShared::try_link_class(ik, THREAD);
1572       guarantee(!HAS_PENDING_EXCEPTION, "exception in link_class");
1573 
1574       ik->constants()->resolve_class_constants(THREAD);
1575     }
1576   }
1577 };
1578 
1579 class CheckSharedClassesClosure : public KlassClosure {
1580   bool    _made_progress;
1581  public:
1582   CheckSharedClassesClosure() : _made_progress(false) {}
1583 
1584   void reset()               { _made_progress = false; }
1585   bool made_progress() const { return _made_progress; }
1586   void do_klass(Klass* k) {
1587     if (k->is_instance_klass() && InstanceKlass::cast(k)->check_sharing_error_state()) {
1588       _made_progress = true;
1589     }
1590   }
1591 };
1592 
1593 void MetaspaceShared::check_shared_class_loader_type(InstanceKlass* ik) {
1594   ResourceMark rm;
1595   if (ik->shared_classpath_index() == UNREGISTERED_INDEX) {
1596     guarantee(ik->loader_type() == 0,
1597             "Class loader type must not be set for this class %s", ik->name()->as_C_string());
1598   } else {
1599     guarantee(ik->loader_type() != 0,
1600             "Class loader type must be set for this class %s", ik->name()->as_C_string());
1601   }
1602 }
1603 
1604 void MetaspaceShared::link_and_cleanup_shared_classes(TRAPS) {
1605   // We need to iterate because verification may cause additional classes
1606   // to be loaded.
1607   LinkSharedClassesClosure link_closure(THREAD);
1608   do {
1609     link_closure.reset();
1610     ClassLoaderDataGraph::loaded_classes_do(&link_closure);
1611     guarantee(!HAS_PENDING_EXCEPTION, "exception in link_class");
1612   } while (link_closure.made_progress());
1613 
1614   if (_has_error_classes) {
1615     // Mark all classes whose super class or interfaces failed verification.
1616     CheckSharedClassesClosure check_closure;
1617     do {
1618       // Not completely sure if we need to do this iteratively. Anyway,
1619       // we should come here only if there are unverifiable classes, which
1620       // shouldn't happen in normal cases. So better safe than sorry.
1621       check_closure.reset();
1622       ClassLoaderDataGraph::loaded_classes_do(&check_closure);
1623     } while (check_closure.made_progress());
1624 
1625     if (IgnoreUnverifiableClassesDuringDump) {
1626       // This is useful when running JCK or SQE tests. You should not
1627       // enable this when running real apps.
1628       SystemDictionary::remove_classes_in_error_state();
1629     } else {
1630       tty->print_cr("Please remove the unverifiable classes from your class list and try again");
1631       exit(1);
1632     }
1633   }
1634 }
1635 
1636 void MetaspaceShared::prepare_for_dumping() {
1637   Arguments::check_unsupported_dumping_properties();
1638   ClassLoader::initialize_shared_path();
1639 }
1640 
1641 // Preload classes from a list, populate the shared spaces and dump to a
1642 // file.
1643 void MetaspaceShared::preload_and_dump(TRAPS) {
1644   { TraceTime timer("Dump Shared Spaces", TRACETIME_LOG(Info, startuptime));
1645     ResourceMark rm;
1646     char class_list_path_str[JVM_MAXPATHLEN];
1647     // Preload classes to be shared.
1648     // Should use some os:: method rather than fopen() here. aB.
1649     const char* class_list_path;
1650     if (SharedClassListFile == NULL) {
1651       // Construct the path to the class list (in jre/lib)
1652       // Walk up two directories from the location of the VM and
1653       // optionally tack on "lib" (depending on platform)
1654       os::jvm_path(class_list_path_str, sizeof(class_list_path_str));
1655       for (int i = 0; i < 3; i++) {
1656         char *end = strrchr(class_list_path_str, *os::file_separator());
1657         if (end != NULL) *end = '\0';
1658       }
1659       int class_list_path_len = (int)strlen(class_list_path_str);
1660       if (class_list_path_len >= 3) {
1661         if (strcmp(class_list_path_str + class_list_path_len - 3, "lib") != 0) {
1662           if (class_list_path_len < JVM_MAXPATHLEN - 4) {
1663             jio_snprintf(class_list_path_str + class_list_path_len,
1664                          sizeof(class_list_path_str) - class_list_path_len,
1665                          "%slib", os::file_separator());
1666             class_list_path_len += 4;
1667           }
1668         }
1669       }
1670       if (class_list_path_len < JVM_MAXPATHLEN - 10) {
1671         jio_snprintf(class_list_path_str + class_list_path_len,
1672                      sizeof(class_list_path_str) - class_list_path_len,
1673                      "%sclasslist", os::file_separator());
1674       }
1675       class_list_path = class_list_path_str;
1676     } else {
1677       class_list_path = SharedClassListFile;
1678     }
1679 
1680     tty->print_cr("Loading classes to share ...");
1681     _has_error_classes = false;
1682     int class_count = preload_classes(class_list_path, THREAD);
1683     if (ExtraSharedClassListFile) {
1684       class_count += preload_classes(ExtraSharedClassListFile, THREAD);
1685     }
1686     tty->print_cr("Loading classes to share: done.");
1687 
1688     log_info(cds)("Shared spaces: preloaded %d classes", class_count);
1689 
1690     // Rewrite and link classes
1691     tty->print_cr("Rewriting and linking classes ...");
1692 
1693     // Link any classes which got missed. This would happen if we have loaded classes that
1694     // were not explicitly specified in the classlist. E.g., if an interface implemented by class K
1695     // fails verification, all other interfaces that were not specified in the classlist but
1696     // are implemented by K are not verified.
1697     link_and_cleanup_shared_classes(CATCH);
1698     tty->print_cr("Rewriting and linking classes: done");
1699 
1700     SystemDictionary::clear_invoke_method_table();
1701     HeapShared::init_archivable_static_fields(THREAD);
1702 
1703     VM_PopulateDumpSharedSpace op;
1704     VMThread::execute(&op);
1705   }
1706 }
1707 
1708 
1709 int MetaspaceShared::preload_classes(const char* class_list_path, TRAPS) {
1710   ClassListParser parser(class_list_path);
1711   int class_count = 0;
1712 
1713     while (parser.parse_one_line()) {
1714       Klass* klass = ClassLoaderExt::load_one_class(&parser, THREAD);
1715       if (HAS_PENDING_EXCEPTION) {
1716         if (klass == NULL &&
1717              (PENDING_EXCEPTION->klass()->name() == vmSymbols::java_lang_ClassNotFoundException())) {
1718           // print a warning only when the pending exception is class not found
1719           tty->print_cr("Preload Warning: Cannot find %s", parser.current_class_name());
1720         }
1721         CLEAR_PENDING_EXCEPTION;
1722       }
1723       if (klass != NULL) {
1724         if (log_is_enabled(Trace, cds)) {
1725           ResourceMark rm;
1726           log_trace(cds)("Shared spaces preloaded: %s", klass->external_name());
1727         }
1728 
1729         if (klass->is_instance_klass()) {
1730           InstanceKlass* ik = InstanceKlass::cast(klass);
1731 
1732           // Link the class to cause the bytecodes to be rewritten and the
1733           // cpcache to be created. The linking is done as soon as classes
1734           // are loaded in order that the related data structures (klass and
1735           // cpCache) are located together.
1736           try_link_class(ik, THREAD);
1737           guarantee(!HAS_PENDING_EXCEPTION, "exception in link_class");
1738         }
1739 
1740         class_count++;
1741       }
1742     }
1743 
1744   return class_count;
1745 }
1746 
1747 // Returns true if the class's status has changed
1748 bool MetaspaceShared::try_link_class(InstanceKlass* ik, TRAPS) {
1749   assert(DumpSharedSpaces, "should only be called during dumping");
1750   if (ik->init_state() < InstanceKlass::linked) {
1751     bool saved = BytecodeVerificationLocal;
1752     if (ik->loader_type() == 0 && ik->class_loader() == NULL) {
1753       // The verification decision is based on BytecodeVerificationRemote
1754       // for non-system classes. Since we are using the NULL classloader
1755       // to load non-system classes for customized class loaders during dumping,
1756       // we need to temporarily change BytecodeVerificationLocal to be the same as
1757       // BytecodeVerificationRemote. Note this can cause the parent system
1758       // classes also being verified. The extra overhead is acceptable during
1759       // dumping.
1760       BytecodeVerificationLocal = BytecodeVerificationRemote;
1761     }
1762     ik->link_class(THREAD);
1763     if (HAS_PENDING_EXCEPTION) {
1764       ResourceMark rm;
1765       tty->print_cr("Preload Warning: Verification failed for %s",
1766                     ik->external_name());
1767       CLEAR_PENDING_EXCEPTION;
1768       ik->set_in_error_state();
1769       _has_error_classes = true;
1770     }
1771     BytecodeVerificationLocal = saved;
1772     return true;
1773   } else {
1774     return false;
1775   }
1776 }
1777 
1778 #if INCLUDE_CDS_JAVA_HEAP
1779 void VM_PopulateDumpSharedSpace::dump_java_heap_objects() {
1780   if (!MetaspaceShared::is_heap_object_archiving_allowed()) {
1781     if (log_is_enabled(Info, cds)) {
1782       log_info(cds)(
1783         "Archived java heap is not supported as UseG1GC, "
1784         "UseCompressedOops and UseCompressedClassPointers are required."
1785         "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
1786         BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
1787         BOOL_TO_STR(UseCompressedClassPointers));
1788     }
1789     return;
1790   }
1791 
1792   {
1793     NoSafepointVerifier nsv;
1794 
1795     // Cache for recording where the archived objects are copied to
1796     MetaspaceShared::create_archive_object_cache();
1797 
1798     tty->print_cr("Dumping objects to closed archive heap region ...");
1799     NOT_PRODUCT(StringTable::verify());
1800     // The closed space has maximum two regions. See FileMapInfo::write_archive_heap_regions() for details.
1801     _closed_archive_heap_regions = new GrowableArray<MemRegion>(2);
1802     MetaspaceShared::dump_closed_archive_heap_objects(_closed_archive_heap_regions);
1803 
1804     tty->print_cr("Dumping objects to open archive heap region ...");
1805     _open_archive_heap_regions = new GrowableArray<MemRegion>(2);
1806     MetaspaceShared::dump_open_archive_heap_objects(_open_archive_heap_regions);
1807 
1808     MetaspaceShared::destroy_archive_object_cache();
1809   }
1810 
1811   G1HeapVerifier::verify_archive_regions();
1812 }
1813 
1814 void MetaspaceShared::dump_closed_archive_heap_objects(
1815                                     GrowableArray<MemRegion> * closed_archive) {
1816   assert(is_heap_object_archiving_allowed(), "Cannot dump java heap objects");
1817 
1818   Thread* THREAD = Thread::current();
1819   G1CollectedHeap::heap()->begin_archive_alloc_range();
1820 
1821   // Archive interned string objects
1822   StringTable::write_to_archive();
1823 
1824   G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
1825                                                    os::vm_allocation_granularity());
1826 }
1827 
1828 void MetaspaceShared::dump_open_archive_heap_objects(
1829                                     GrowableArray<MemRegion> * open_archive) {
1830   assert(UseG1GC, "Only support G1 GC");
1831   assert(UseCompressedOops && UseCompressedClassPointers,
1832          "Only support UseCompressedOops and UseCompressedClassPointers enabled");
1833 
1834   Thread* THREAD = Thread::current();
1835   G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
1836 
1837   java_lang_Class::archive_basic_type_mirrors(THREAD);
1838 
1839   MetaspaceShared::archive_klass_objects(THREAD);
1840 
1841   HeapShared::archive_module_graph_objects(THREAD);
1842 
1843   G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
1844                                                    os::vm_allocation_granularity());
1845 }
1846 
1847 unsigned MetaspaceShared::obj_hash(oop const& p) {
1848   assert(!p->mark()->has_bias_pattern(),
1849          "this object should never have been locked");  // so identity_hash won't safepoin
1850   unsigned hash = (unsigned)p->identity_hash();
1851   return hash;
1852 }
1853 
1854 MetaspaceShared::ArchivedObjectCache* MetaspaceShared::_archive_object_cache = NULL;
1855 oop MetaspaceShared::find_archived_heap_object(oop obj) {
1856   assert(DumpSharedSpaces, "dump-time only");
1857   ArchivedObjectCache* cache = MetaspaceShared::archive_object_cache();
1858   oop* p = cache->get(obj);
1859   if (p != NULL) {
1860     return *p;
1861   } else {
1862     return NULL;
1863   }
1864 }
1865 
1866 oop MetaspaceShared::archive_heap_object(oop obj, Thread* THREAD) {
1867   assert(DumpSharedSpaces, "dump-time only");
1868 
1869   oop ao = find_archived_heap_object(obj);
1870   if (ao != NULL) {
1871     // already archived
1872     return ao;
1873   }
1874 
1875   int len = obj->size();
1876   if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
1877     log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
1878                          p2i(obj), (size_t)obj->size());
1879     return NULL;
1880   }
1881 
1882   int hash = obj->identity_hash();
1883   oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
1884   if (archived_oop != NULL) {
1885     Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)archived_oop, len);
1886     relocate_klass_ptr(archived_oop);
1887     ArchivedObjectCache* cache = MetaspaceShared::archive_object_cache();
1888     cache->put(obj, archived_oop);
1889     log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT,
1890                          p2i(obj), p2i(archived_oop));
1891   } else {
1892     log_error(cds, heap)(
1893       "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
1894       p2i(obj));
1895     vm_exit(1);
1896   }
1897   return archived_oop;
1898 }
1899 
1900 oop MetaspaceShared::materialize_archived_object(oop obj) {
1901   if (obj != NULL) {
1902     return G1CollectedHeap::heap()->materialize_archived_object(obj);
1903   }
1904   return NULL;
1905 }
1906 
1907 void MetaspaceShared::archive_klass_objects(Thread* THREAD) {
1908   int i;
1909   for (i = 0; i < _global_klass_objects->length(); i++) {
1910     Klass* k = _global_klass_objects->at(i);
1911 
1912     // archive mirror object
1913     java_lang_Class::archive_mirror(k, CHECK);
1914 
1915     // archive the resolved_referenes array
1916     if (k->is_instance_klass()) {
1917       InstanceKlass* ik = InstanceKlass::cast(k);
1918       ik->constants()->archive_resolved_references(THREAD);
1919     }
1920   }
1921 }
1922 
1923 bool MetaspaceShared::is_archive_object(oop p) {
1924   return (p == NULL) ? false : G1ArchiveAllocator::is_archive_object(p);
1925 }
1926 
1927 void MetaspaceShared::fixup_mapped_heap_regions() {
1928   FileMapInfo *mapinfo = FileMapInfo::current_info();
1929   mapinfo->fixup_mapped_heap_regions();
1930 }
1931 #endif // INCLUDE_CDS_JAVA_HEAP
1932 
1933 // Closure for serializing initialization data in from a data area
1934 // (ptr_array) read from the shared file.
1935 
1936 class ReadClosure : public SerializeClosure {
1937 private:
1938   intptr_t** _ptr_array;
1939 
1940   inline intptr_t nextPtr() {
1941     return *(*_ptr_array)++;
1942   }
1943 
1944 public:
1945   ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; }
1946 
1947   void do_ptr(void** p) {
1948     assert(*p == NULL, "initializing previous initialized pointer.");
1949     intptr_t obj = nextPtr();
1950     assert((intptr_t)obj >= 0 || (intptr_t)obj < -100,
1951            "hit tag while initializing ptrs.");
1952     *p = (void*)obj;
1953   }
1954 
1955   void do_u4(u4* p) {
1956     intptr_t obj = nextPtr();
1957     *p = (u4)(uintx(obj));
1958   }
1959 
1960   void do_tag(int tag) {
1961     int old_tag;
1962     old_tag = (int)(intptr_t)nextPtr();
1963     // do_int(&old_tag);
1964     assert(tag == old_tag, "old tag doesn't match");
1965     FileMapInfo::assert_mark(tag == old_tag);
1966   }
1967 
1968   void do_oop(oop *p) {
1969     narrowOop o = (narrowOop)nextPtr();
1970     if (o == 0 || !MetaspaceShared::open_archive_heap_region_mapped()) {
1971       p = NULL;
1972     } else {
1973       assert(MetaspaceShared::is_heap_object_archiving_allowed(),
1974              "Archived heap object is not allowed");
1975       assert(MetaspaceShared::open_archive_heap_region_mapped(),
1976              "Open archive heap region is not mapped");
1977       *p = CompressedOops::decode_not_null(o);
1978     }
1979   }
1980 
1981   void do_region(u_char* start, size_t size) {
1982     assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment");
1983     assert(size % sizeof(intptr_t) == 0, "bad size");
1984     do_tag((int)size);
1985     while (size > 0) {
1986       *(intptr_t*)start = nextPtr();
1987       start += sizeof(intptr_t);
1988       size -= sizeof(intptr_t);
1989     }
1990   }
1991 
1992   bool reading() const { return true; }
1993 };
1994 
1995 // Return true if given address is in the misc data region
1996 bool MetaspaceShared::is_in_shared_region(const void* p, int idx) {
1997   return UseSharedSpaces && FileMapInfo::current_info()->is_in_shared_region(p, idx);
1998 }
1999 
2000 bool MetaspaceShared::is_in_trampoline_frame(address addr) {
2001   if (UseSharedSpaces && is_in_shared_region(addr, MetaspaceShared::mc)) {
2002     return true;
2003   }
2004   return false;
2005 }
2006 
2007 void MetaspaceShared::print_shared_spaces() {
2008   if (UseSharedSpaces) {
2009     FileMapInfo::current_info()->print_shared_spaces();
2010   }
2011 }
2012 
2013 
2014 // Map shared spaces at requested addresses and return if succeeded.
2015 bool MetaspaceShared::map_shared_spaces(FileMapInfo* mapinfo) {
2016   size_t image_alignment = mapinfo->alignment();
2017 
2018 #ifndef _WINDOWS
2019   // Map in the shared memory and then map the regions on top of it.
2020   // On Windows, don't map the memory here because it will cause the
2021   // mappings of the regions to fail.
2022   ReservedSpace shared_rs = mapinfo->reserve_shared_memory();
2023   if (!shared_rs.is_reserved()) return false;
2024 #endif
2025 
2026   assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
2027 
2028   char* ro_base = NULL; char* ro_top;
2029   char* rw_base = NULL; char* rw_top;
2030   char* mc_base = NULL; char* mc_top;
2031   char* md_base = NULL; char* md_top;
2032   char* od_base = NULL; char* od_top;
2033 
2034   // Map each shared region
2035   if ((mc_base = mapinfo->map_region(mc, &mc_top)) != NULL &&
2036       (rw_base = mapinfo->map_region(rw, &rw_top)) != NULL &&
2037       (ro_base = mapinfo->map_region(ro, &ro_top)) != NULL &&
2038       (md_base = mapinfo->map_region(md, &md_top)) != NULL &&
2039       (od_base = mapinfo->map_region(od, &od_top)) != NULL &&
2040       (image_alignment == (size_t)os::vm_allocation_granularity()) &&
2041       mapinfo->validate_shared_path_table()) {
2042     // Success -- set up MetaspaceObj::_shared_metaspace_{base,top} for
2043     // fast checking in MetaspaceShared::is_in_shared_metaspace() and
2044     // MetaspaceObj::is_shared().
2045     //
2046     // We require that mc->rw->ro->md->od to be laid out consecutively, with no
2047     // gaps between them. That way, we can ensure that the OS won't be able to
2048     // allocate any new memory spaces inside _shared_metaspace_{base,top}, which
2049     // would mess up the simple comparision in MetaspaceShared::is_in_shared_metaspace().
2050     assert(mc_base < ro_base && mc_base < rw_base && mc_base < md_base && mc_base < od_base, "must be");
2051     assert(od_top  > ro_top  && od_top  > rw_top  && od_top  > md_top  && od_top  > mc_top , "must be");
2052     assert(mc_top == rw_base, "must be");
2053     assert(rw_top == ro_base, "must be");
2054     assert(ro_top == md_base, "must be");
2055     assert(md_top == od_base, "must be");
2056 
2057     MetaspaceObj::set_shared_metaspace_range((void*)mc_base, (void*)od_top);
2058     return true;
2059   } else {
2060     // If there was a failure in mapping any of the spaces, unmap the ones
2061     // that succeeded
2062     if (ro_base != NULL) mapinfo->unmap_region(ro);
2063     if (rw_base != NULL) mapinfo->unmap_region(rw);
2064     if (mc_base != NULL) mapinfo->unmap_region(mc);
2065     if (md_base != NULL) mapinfo->unmap_region(md);
2066     if (od_base != NULL) mapinfo->unmap_region(od);
2067 #ifndef _WINDOWS
2068     // Release the entire mapped region
2069     shared_rs.release();
2070 #endif
2071     // If -Xshare:on is specified, print out the error message and exit VM,
2072     // otherwise, set UseSharedSpaces to false and continue.
2073     if (RequireSharedSpaces || PrintSharedArchiveAndExit) {
2074       vm_exit_during_initialization("Unable to use shared archive.", "Failed map_region for using -Xshare:on.");
2075     } else {
2076       FLAG_SET_DEFAULT(UseSharedSpaces, false);
2077     }
2078     return false;
2079   }
2080 }
2081 
2082 // Read the miscellaneous data from the shared file, and
2083 // serialize it out to its various destinations.
2084 
2085 void MetaspaceShared::initialize_shared_spaces() {
2086   FileMapInfo *mapinfo = FileMapInfo::current_info();
2087   _cds_i2i_entry_code_buffers = mapinfo->cds_i2i_entry_code_buffers();
2088   _cds_i2i_entry_code_buffers_size = mapinfo->cds_i2i_entry_code_buffers_size();
2089   _core_spaces_size = mapinfo->core_spaces_size();
2090   char* buffer = mapinfo->misc_data_patching_start();
2091   clone_cpp_vtables((intptr_t*)buffer);
2092 
2093   // The rest of the data is now stored in the RW region
2094   buffer = mapinfo->read_only_tables_start();
2095   int sharedDictionaryLen = *(intptr_t*)buffer;
2096   buffer += sizeof(intptr_t);
2097   int number_of_entries = *(intptr_t*)buffer;
2098   buffer += sizeof(intptr_t);
2099   SystemDictionary::set_shared_dictionary((HashtableBucket<mtClass>*)buffer,
2100                                           sharedDictionaryLen,
2101                                           number_of_entries);
2102   buffer += sharedDictionaryLen;
2103 
2104   // The following data are the linked list elements
2105   // (HashtableEntry objects) for the shared dictionary table.
2106 
2107   int len = *(intptr_t*)buffer;     // skip over shared dictionary entries
2108   buffer += sizeof(intptr_t);
2109   buffer += len;
2110 
2111   // The table of archived java heap object sub-graph infos
2112   buffer = HeapShared::read_archived_subgraph_infos(buffer);
2113 
2114   // Verify various attributes of the archive, plus initialize the
2115   // shared string/symbol tables
2116   intptr_t* array = (intptr_t*)buffer;
2117   ReadClosure rc(&array);
2118   serialize(&rc);
2119 
2120   // Initialize the run-time symbol table.
2121   SymbolTable::create_table();
2122 
2123   // Close the mapinfo file
2124   mapinfo->close();
2125 
2126   if (PrintSharedArchiveAndExit) {
2127     if (PrintSharedDictionary) {
2128       tty->print_cr("\nShared classes:\n");
2129       SystemDictionary::print_shared(tty);
2130     }
2131     if (_archive_loading_failed) {
2132       tty->print_cr("archive is invalid");
2133       vm_exit(1);
2134     } else {
2135       tty->print_cr("archive is valid");
2136       vm_exit(0);
2137     }
2138   }
2139 }
2140 
2141 // JVM/TI RedefineClasses() support:
2142 bool MetaspaceShared::remap_shared_readonly_as_readwrite() {
2143   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2144 
2145   if (UseSharedSpaces) {
2146     // remap the shared readonly space to shared readwrite, private
2147     FileMapInfo* mapinfo = FileMapInfo::current_info();
2148     if (!mapinfo->remap_shared_readonly_as_readwrite()) {
2149       return false;
2150     }
2151     _remapped_readwrite = true;
2152   }
2153   return true;
2154 }
2155 
2156 void MetaspaceShared::report_out_of_space(const char* name, size_t needed_bytes) {
2157   // This is highly unlikely to happen on 64-bits because we have reserved a 4GB space.
2158   // On 32-bit we reserve only 256MB so you could run out of space with 100,000 classes
2159   // or so.
2160   _mc_region.print_out_of_space_msg(name, needed_bytes);
2161   _rw_region.print_out_of_space_msg(name, needed_bytes);
2162   _ro_region.print_out_of_space_msg(name, needed_bytes);
2163   _md_region.print_out_of_space_msg(name, needed_bytes);
2164   _od_region.print_out_of_space_msg(name, needed_bytes);
2165 
2166   vm_exit_during_initialization(err_msg("Unable to allocate from '%s' region", name),
2167                                 "Please reduce the number of shared classes.");
2168 }