1 /*

     2  * Copyright (c) 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 "classfile/javaClasses.inline.hpp"

    27 #include "classfile/vmSymbols.hpp"

    28 #include "logging/log.hpp"

    29 #include "logging/logMessage.hpp"

    30 #include "logging/logStream.hpp"

    31 #include "memory/heapShared.hpp"

    32 #include "memory/iterator.inline.hpp"

    33 #include "memory/metadataFactory.hpp"

    34 #include "memory/metaspaceClosure.hpp"

    35 #include "memory/metaspaceShared.hpp"

    36 #include "memory/resourceArea.hpp"

    37 #include "oops/compressedOops.inline.hpp"

    38 #include "oops/oop.inline.hpp"

    39 

    40 #if INCLUDE_CDS_JAVA_HEAP

    41 KlassSubGraphInfo* HeapShared::_subgraph_info_list = NULL;

    42 int HeapShared::_num_archived_subgraph_info_records = 0;

    43 Array<ArchivedKlassSubGraphInfoRecord>* HeapShared::_archived_subgraph_info_records = NULL;

    44 

    45 // Currently there is only one class mirror (ArchivedModuleGraph) with archived

    46 // sub-graphs.

    47 KlassSubGraphInfo* HeapShared::find_subgraph_info(Klass* k) {

    48   KlassSubGraphInfo* info = _subgraph_info_list;

    49   while (info != NULL) {

    50     if (info->klass() == k) {

    51       return info;

    52     }

    53     info = info->next();

    54   }

    55   return NULL;

    56 }

    57 

    58 // Get the subgraph_info for Klass k. A new subgraph_info is created if

    59 // there is no existing one for k. The subgraph_info records the relocated

    60 // Klass* of the original k.

    61 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {

    62   Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);

    63   KlassSubGraphInfo* info = find_subgraph_info(relocated_k);

    64   if (info != NULL) {

    65     return info;

    66   }

    67 

    68   info = new KlassSubGraphInfo(relocated_k, _subgraph_info_list);

    69   _subgraph_info_list = info;

    70   return info;

    71 }

    72 

    73 int HeapShared::num_of_subgraph_infos() {

    74   int num = 0;

    75   KlassSubGraphInfo* info = _subgraph_info_list;

    76   while (info != NULL) {

    77     num ++;

    78     info = info->next();

    79   }

    80   return num;

    81 }

    82 

    83 // Add an entry field to the current KlassSubGraphInfo.

    84 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {

    85   assert(DumpSharedSpaces, "dump time only");

    86   if (_subgraph_entry_fields == NULL) {

    87     _subgraph_entry_fields =

    88       new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true);

    89   }

    90   _subgraph_entry_fields->append((juint)static_field_offset);

    91   _subgraph_entry_fields->append(CompressedOops::encode(v));

    92 }

    93 

    94 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.

    95 // Only objects of boot classes can be included in sub-graph.

    96 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {

    97   assert(DumpSharedSpaces, "dump time only");

    98   assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),

    99          "must be the relocated Klass in the shared space");

   100 

   101   if (_subgraph_object_klasses == NULL) {

   102     _subgraph_object_klasses =

   103       new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true);

   104   }

   105 

   106   assert(relocated_k->is_shared(), "must be a shared class");

   107   if (relocated_k->is_instance_klass()) {

   108     assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),

   109           "must be boot class");

   110     // SystemDictionary::xxx_klass() are not updated, need to check

   111     // the original Klass*

   112     if (orig_k == SystemDictionary::String_klass() ||

   113         orig_k == SystemDictionary::Object_klass()) {

   114       // Initialized early during VM initialization. No need to be added

   115       // to the sub-graph object class list.

   116       return;

   117     }

   118   } else if (relocated_k->is_objArray_klass()) {

   119     Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();

   120     if (abk->is_instance_klass()) {

   121       assert(InstanceKlass::cast(abk)->is_shared_boot_class(),

   122             "must be boot class");

   123     }

   124     if (relocated_k == Universe::objectArrayKlassObj()) {

   125       // Initialized early during Universe::genesis. No need to be added

   126       // to the list.

   127       return;

   128     }

   129   } else {

   130     assert(relocated_k->is_typeArray_klass(), "must be");

   131     // Primitive type arrays are created early during Universe::genesis.

   132     return;

   133   }

   134 

   135   _subgraph_object_klasses->append_if_missing(relocated_k);

   136 }

   137 

   138 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.

   139 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {

   140   _k = info->klass();

   141   _next = NULL;

   142   _entry_field_records = NULL;

   143   _subgraph_klasses = NULL;

   144 

   145   // populate the entry fields

   146   GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();

   147   if (entry_fields != NULL) {

   148     int num_entry_fields = entry_fields->length();

   149     assert(num_entry_fields % 2 == 0, "sanity");

   150     _entry_field_records =

   151       MetaspaceShared::new_ro_array<juint>(num_entry_fields);

   152     for (int i = 0 ; i < num_entry_fields; i++) {

   153       _entry_field_records->at_put(i, entry_fields->at(i));

   154     }

   155   }

   156 

   157   // the Klasses of the objects in the sub-graphs

   158   GrowableArray<Klass*>* subgraph_klasses = info->subgraph_object_klasses();

   159   if (subgraph_klasses != NULL) {

   160     int num_subgraphs_klasses = subgraph_klasses->length();

   161     _subgraph_klasses =

   162       MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);

   163     for (int i = 0; i < num_subgraphs_klasses; i++) {

   164       Klass* subgraph_k = subgraph_klasses->at(i);

   165       if (log_is_enabled(Info, cds, heap)) {

   166         ResourceMark rm;

   167         log_info(cds, heap)(

   168           "Archived object klass (%d): %s in %s sub-graphs",

   169           i, subgraph_k->external_name(), _k->external_name());

   170       }

   171       _subgraph_klasses->at_put(i, subgraph_k);

   172     }

   173   }

   174 }

   175 

   176 // Build the records of archived subgraph infos, which include:

   177 // - Entry points to all subgraphs from the containing class mirror. The entry

   178 //   points are static fields in the mirror. For each entry point, the field

   179 //   offset and value are recorded in the sub-graph info. The value are stored

   180 //   back to the corresponding field at runtime.

   181 // - A list of klasses that need to be loaded/initialized before archived

   182 //   java object sub-graph can be accessed at runtime.

   183 //

   184 // The records are saved in the archive file and reloaded at runtime. Currently

   185 // there is only one class mirror (ArchivedModuleGraph) with archived sub-graphs.

   186 //

   187 // Layout of the archived subgraph info records:

   188 //

   189 // records_size | num_records | records*

   190 // ArchivedKlassSubGraphInfoRecord | entry_fields | subgraph_object_klasses

   191 size_t HeapShared::build_archived_subgraph_info_records(int num_records) {

   192   // remember the start address

   193   char* start_p = MetaspaceShared::read_only_space_top();

   194 

   195   // now populate the archived subgraph infos, which will be saved in the

   196   // archive file

   197   _archived_subgraph_info_records =

   198     MetaspaceShared::new_ro_array<ArchivedKlassSubGraphInfoRecord>(num_records);

   199   KlassSubGraphInfo* info = _subgraph_info_list;

   200   int i = 0;

   201   while (info != NULL) {

   202     assert(i < _archived_subgraph_info_records->length(), "sanity");

   203     ArchivedKlassSubGraphInfoRecord* record =

   204       _archived_subgraph_info_records->adr_at(i);

   205     record->init(info);

   206     info = info->next();

   207     i ++;

   208   }

   209 

   210   // _subgraph_info_list is no longer needed

   211   delete _subgraph_info_list;

   212   _subgraph_info_list = NULL;

   213 

   214   char* end_p = MetaspaceShared::read_only_space_top();

   215   size_t records_size = end_p - start_p;

   216   return records_size;

   217 }

   218 

   219 // Write the subgraph info records in the shared _ro region

   220 void HeapShared::write_archived_subgraph_infos() {

   221   assert(DumpSharedSpaces, "dump time only");

   222 

   223   Array<intptr_t>* records_header = MetaspaceShared::new_ro_array<intptr_t>(3);

   224 

   225   _num_archived_subgraph_info_records = num_of_subgraph_infos();

   226   size_t records_size = build_archived_subgraph_info_records(

   227                              _num_archived_subgraph_info_records);

   228 

   229   // Now write the header information:

   230   // records_size, num_records, _archived_subgraph_info_records

   231   assert(records_header != NULL, "sanity");

   232   intptr_t* p = (intptr_t*)(records_header->data());

   233   *p = (intptr_t)records_size;

   234   p ++;

   235   *p = (intptr_t)_num_archived_subgraph_info_records;

   236   p ++;

   237   *p = (intptr_t)_archived_subgraph_info_records;

   238 }

   239 

   240 char* HeapShared::read_archived_subgraph_infos(char* buffer) {

   241   Array<intptr_t>* records_header = (Array<intptr_t>*)buffer;

   242   intptr_t* p = (intptr_t*)(records_header->data());

   243   size_t records_size = (size_t)(*p);

   244   p ++;

   245   _num_archived_subgraph_info_records = *p;

   246   p ++;

   247   _archived_subgraph_info_records =

   248     (Array<ArchivedKlassSubGraphInfoRecord>*)(*p);

   249 

   250   buffer = (char*)_archived_subgraph_info_records + records_size;

   251   return buffer;

   252 }

   253 

   254 void HeapShared::initialize_from_archived_subgraph(Klass* k) {

   255   if (!MetaspaceShared::open_archive_heap_region_mapped()) {

   256     return; // nothing to do

   257   }

   258 

   259   if (_num_archived_subgraph_info_records == 0) {

   260     return; // no subgraph info records

   261   }

   262 

   263   // Initialize from archived data. Currently only ArchivedModuleGraph

   264   // has archived object subgraphs, which is used during VM initialization

   265   // time when bootstraping the system modules. No lock is needed.

   266   Thread* THREAD = Thread::current();

   267   for (int i = 0; i < _archived_subgraph_info_records->length(); i++) {

   268     ArchivedKlassSubGraphInfoRecord* record = _archived_subgraph_info_records->adr_at(i);

   269     if (record->klass() == k) {

   270       int i;

   271       // Found the archived subgraph info record for the requesting klass.

   272       // Load/link/initialize the klasses of the objects in the subgraph.

   273       // NULL class loader is used.

   274       Array<Klass*>* klasses = record->subgraph_klasses();

   275       if (klasses != NULL) {

   276         for (i = 0; i < klasses->length(); i++) {

   277           Klass* obj_k = klasses->at(i);

   278           Klass* resolved_k = SystemDictionary::resolve_or_null(

   279                                                 (obj_k)->name(), THREAD);

   280           if (resolved_k != obj_k) {

   281             return;

   282           }

   283           if ((obj_k)->is_instance_klass()) {

   284             InstanceKlass* ik = InstanceKlass::cast(obj_k);

   285             ik->initialize(THREAD);

   286           } else if ((obj_k)->is_objArray_klass()) {

   287             ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);

   288             oak->initialize(THREAD);

   289           }

   290         }

   291       }

   292 

   293       if (HAS_PENDING_EXCEPTION) {

   294         CLEAR_PENDING_EXCEPTION;

   295         // None of the field value will be set if there was an exception.

   296         // The java code will not see any of the archived objects in the

   297         // subgraphs referenced from k in this case.

   298         return;

   299       }

   300 

   301       // Load the subgraph entry fields from the record and store them back to

   302       // the corresponding fields within the mirror.

   303       oop m = k->java_mirror();

   304       Array<juint>* entry_field_records = record->entry_field_records();

   305       if (entry_field_records != NULL) {

   306         int efr_len = entry_field_records->length();

   307         assert(efr_len % 2 == 0, "sanity");

   308         for (i = 0; i < efr_len;) {

   309           int field_offset = entry_field_records->at(i);

   310           // The object refereced by the field becomes 'known' by GC from this

   311           // point. All objects in the subgraph reachable from the object are

   312           // also 'known' by GC.

   313           oop v = MetaspaceShared::materialize_archived_object(

   314             CompressedOops::decode(entry_field_records->at(i+1)));

   315           m->obj_field_put(field_offset, v);

   316           i += 2;

   317         }

   318       }

   319 

   320       // Done. Java code can see the archived sub-graphs referenced from k's

   321       // mirror after this point.

   322       return;

   323     }

   324   }

   325 }

   326 

   327 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {

   328   int _level;

   329   KlassSubGraphInfo* _subgraph_info;

   330   oop _orig_referencing_obj;

   331   oop _archived_referencing_obj;

   332  public:

   333   WalkOopAndArchiveClosure(int level, KlassSubGraphInfo* subgraph_info,

   334            oop orig, oop archived) : _level(level),

   335                                      _subgraph_info(subgraph_info),

   336                                      _orig_referencing_obj(orig),

   337                                      _archived_referencing_obj(archived) {}

   338   void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }

   339   void do_oop(      oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }

   340 

   341  protected:

   342   template <class T> void do_oop_work(T *p) {

   343     oop obj = RawAccess<>::oop_load(p);

   344     if (!CompressedOops::is_null(obj)) {

   345       // A java.lang.Class instance can not be included in an archived

   346       // object sub-graph.

   347       if (java_lang_Class::is_instance(obj)) {

   348         tty->print("Unknown java.lang.Class object is in the archived sub-graph\n");

   349         vm_exit(1);

   350       }

   351 

   352       LogTarget(Debug, cds, heap) log;

   353       LogStream ls(log);

   354       outputStream* out = &ls;

   355       {

   356         ResourceMark rm;

   357         log.print("(%d) %s <--- referenced from:  %s",

   358                   _level, obj->klass()->external_name(),

   359                   CompressedOops::is_null(_orig_referencing_obj) ?

   360                          "" : _orig_referencing_obj->klass()->external_name());

   361         obj->print_on(out);

   362       }

   363 

   364       if (MetaspaceShared::is_archive_object(obj)) {

   365         // The current oop is an archived oop, nothing needs to be done

   366         log.print("--- object is already archived ---");

   367         return;

   368       }

   369 

   370       size_t field_delta = pointer_delta(

   371         p, _orig_referencing_obj, sizeof(char));

   372       T* new_p = (T*)(address(_archived_referencing_obj) + field_delta);

   373       oop archived = MetaspaceShared::find_archived_heap_object(obj);

   374       if (archived != NULL) {

   375         // There is an archived copy existing, update reference to point

   376         // to the archived copy

   377         RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);

   378         log.print(

   379           "--- found existing archived copy, store archived " PTR_FORMAT " in " PTR_FORMAT,

   380           p2i(archived), p2i(new_p));

   381         return;

   382       }

   383 

   384       int l = _level + 1;

   385       Thread* THREAD = Thread::current();

   386       // Archive the current oop before iterating through its references

   387       archived = MetaspaceShared::archive_heap_object(obj, THREAD);

   388       assert(MetaspaceShared::is_archive_object(archived), "must be archived");

   389       log.print("=== archiving oop " PTR_FORMAT " ==> " PTR_FORMAT,

   390                  p2i(obj), p2i(archived));

   391 

   392       // Following the references in the current oop and archive any

   393       // encountered objects during the process

   394       WalkOopAndArchiveClosure walker(l, _subgraph_info, obj, archived);

   395       obj->oop_iterate(&walker);

   396 

   397       // Update the reference in the archived copy of the referencing object

   398       RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);

   399       log.print("=== store archived " PTR_FORMAT " in " PTR_FORMAT,

   400                 p2i(archived), p2i(new_p));

   401 

   402       // Add the klass to the list of classes that need to be loaded before

   403       // module system initialization

   404       Klass *orig_k = obj->klass();

   405       Klass *relocated_k = archived->klass();

   406       _subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);

   407     }

   408   }

   409 };

   410 

   411 //

   412 // Start from the given static field in a java mirror and archive the

   413 // complete sub-graph of java heap objects that are reached directly

   414 // or indirectly from the starting object by following references.

   415 // Currently, only ArchivedModuleGraph class instance (mirror) has archived

   416 // object subgraphs. Sub-graph archiving restrictions (current):

   417 //

   418 // - All classes of objects in the archived sub-graph (including the

   419 //   entry class) must be boot class only.

   420 // - No java.lang.Class instance (java mirror) can be included inside

   421 //   an archived sub-graph. Mirror can only be the sub-graph entry object.

   422 //

   423 // The Java heap object sub-graph archiving process (see

   424 // WalkOopAndArchiveClosure):

   425 //

   426 // 1) Java object sub-graph archiving starts from a given static field

   427 // within a Class instance (java mirror). If the static field is a

   428 // refererence field and points to a non-null java object, proceed to

   429 // the next step.

   430 //

   431 // 2) Archives the referenced java object. If an archived copy of the

   432 // current object already exists, updates the pointer in the archived

   433 // copy of the referencing object to point to the current archived object.

   434 // Otherwise, proceed to the next step.

   435 //

   436 // 3) Follows all references within the current java object and recursively

   437 // archive the sub-graph of objects starting from each reference.

   438 //

   439 // 4) Updates the pointer in the archived copy of referencing object to

   440 //    point to the current archived object.

   441 //

   442 // 5) The Klass of the current java object is added to the list of Klasses

   443 // for loading and initialzing before any object in the archived graph can

   444 // be accessed at runtime.

   445 //

   446 void HeapShared::archive_reachable_objects_from_static_field(Klass *k,

   447                                                              int field_offset,

   448                                                              BasicType field_type,

   449                                                              TRAPS) {

   450   assert(DumpSharedSpaces, "dump time only");

   451   assert(k->is_instance_klass(), "sanity");

   452   assert(InstanceKlass::cast(k)->is_shared_boot_class(),

   453          "must be boot class");

   454 

   455   oop m = k->java_mirror();

   456   oop archived_m = MetaspaceShared::find_archived_heap_object(m);

   457   if (CompressedOops::is_null(archived_m)) {

   458     return;

   459   }

   460 

   461   if (field_type == T_OBJECT) {

   462     // obtain k's subGraph Info

   463     KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);

   464 

   465     // get the object referenced by the field

   466     oop f = m->obj_field(field_offset);

   467     if (!CompressedOops::is_null(f)) {

   468       LogTarget(Debug, cds, heap) log;

   469       LogStream ls(log);

   470       outputStream* out = &ls;

   471       log.print("Start from: ");

   472       f->print_on(out);

   473 

   474       // get the archived copy of the field referenced object

   475       oop af = MetaspaceShared::archive_heap_object(f, THREAD);

   476       if (!MetaspaceShared::is_archive_object(f)) {

   477         WalkOopAndArchiveClosure walker(1, subgraph_info, f, af);

   478         f->oop_iterate(&walker);

   479       }

   480 

   481       // The field value is not preserved in the archived mirror.

   482       // Record the field as a new subGraph entry point. The recorded

   483       // information is restored from the archive at runtime.

   484       subgraph_info->add_subgraph_entry_field(field_offset, af);

   485       Klass *relocated_k = af->klass();

   486       Klass *orig_k = f->klass();

   487       subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);

   488     } else {

   489       // The field contains null, we still need to record the entry point,

   490       // so it can be restored at runtime.

   491       subgraph_info->add_subgraph_entry_field(field_offset, NULL);

   492     }

   493   } else {

   494     ShouldNotReachHere();

   495   }

   496 }

   497 

   498 #define do_module_object_graph(archive_object_graph_do) \

   499   archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedSystemModules_offset(), T_OBJECT, CHECK); \

   500   archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedModuleFinder_offset(), T_OBJECT, CHECK); \

   501   archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedMainModule_offset(), T_OBJECT, CHECK)

   502 

   503 void HeapShared::archive_module_graph_objects(Thread* THREAD) {

   504   do_module_object_graph(archive_reachable_objects_from_static_field);

   505 }

   506 #endif // INCLUDE_CDS_JAVA_HEAP