/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "classfile/javaClasses.inline.hpp"

#include "classfile/symbolTable.hpp"

#include "classfile/vmSymbols.hpp"

#include "logging/log.hpp"

#include "logging/logMessage.hpp"

#include "logging/logStream.hpp"

#include "memory/heapShared.inline.hpp"

#include "memory/iterator.inline.hpp"

#include "memory/metadataFactory.hpp"

#include "memory/metaspaceClosure.hpp"

#include "memory/metaspaceShared.hpp"

#include "memory/resourceArea.hpp"

#include "oops/compressedOops.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/fieldDescriptor.inline.hpp"

#include "utilities/bitMap.inline.hpp"

#if INCLUDE_CDS_JAVA_HEAP

KlassSubGraphInfo* HeapShared::_subgraph_info_list = NULL;

int HeapShared::_num_archived_subgraph_info_records = 0;

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

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

  KlassSubGraphInfo* info = _subgraph_info_list;

  while (info != NULL) {

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

      return info;

    }

    info = info->next();

  }

  return NULL;

}

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

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

// Klass* of the original k.

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

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

  KlassSubGraphInfo* info = find_subgraph_info(relocated_k);

  if (info != NULL) {

    return info;

  }

  info = new KlassSubGraphInfo(relocated_k, _subgraph_info_list);

  _subgraph_info_list = info;

  return info;

}

address   HeapShared::_narrow_oop_base;

int       HeapShared::_narrow_oop_shift;

int HeapShared::num_of_subgraph_infos() {

  int num = 0;

  KlassSubGraphInfo* info = _subgraph_info_list;

  while (info != NULL) {

    num ++;

    info = info->next();

  }

  return num;

}

// Add an entry field to the current KlassSubGraphInfo.

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

  assert(DumpSharedSpaces, "dump time only");

  if (_subgraph_entry_fields == NULL) {

    _subgraph_entry_fields =

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

  }

  _subgraph_entry_fields->append((juint)static_field_offset);

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

}

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

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

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

  assert(DumpSharedSpaces, "dump time only");

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

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

  if (_subgraph_object_klasses == NULL) {

    _subgraph_object_klasses =

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

  }

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

  if (_k == relocated_k) {

    // Don't add the Klass containing the sub-graph to it's own klass

    // initialization list.

    return;

  }

  if (relocated_k->is_instance_klass()) {

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

          "must be boot class");

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

    // the original Klass*

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

        orig_k == SystemDictionary::Object_klass()) {

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

      // to the sub-graph object class list.

      return;

    }

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

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

    if (abk->is_instance_klass()) {

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

            "must be boot class");

    }

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

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

      // to the list.

      return;

    }

  } else {

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

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

    return;

  }

  if (log_is_enabled(Debug, cds, heap)) {

    if (!_subgraph_object_klasses->contains(relocated_k)) {

      ResourceMark rm;

      log_debug(cds, heap)("Adding klass %s", orig_k->external_name());

    }

  }

  _subgraph_object_klasses->append_if_missing(relocated_k);

}

// Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.

void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {

  _k = info->klass();

  _next = NULL;

  _entry_field_records = NULL;

  _subgraph_object_klasses = NULL;

  // populate the entry fields

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

  if (entry_fields != NULL) {

    int num_entry_fields = entry_fields->length();

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

    _entry_field_records =

      MetaspaceShared::new_ro_array<juint>(num_entry_fields);

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

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

    }

  }

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

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

  if (subgraph_object_klasses != NULL) {

    int num_subgraphs_klasses = subgraph_object_klasses->length();

    _subgraph_object_klasses =

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

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

      Klass* subgraph_k = subgraph_object_klasses->at(i);

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

        ResourceMark rm;

        log_info(cds, heap)(

          "Archived object klass %s (%2d) => %s",

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

      }

      _subgraph_object_klasses->at_put(i, subgraph_k);

    }

  }

}

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

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

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

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

//   back to the corresponding field at runtime.

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

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

//

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

//

// Layout of the archived subgraph info records:

//

// records_size | num_records | records*

// ArchivedKlassSubGraphInfoRecord | entry_fields | subgraph_object_klasses

size_t HeapShared::build_archived_subgraph_info_records(int num_records) {

  // remember the start address

  char* start_p = MetaspaceShared::read_only_space_top();

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

  // archive file

  _archived_subgraph_info_records =

    MetaspaceShared::new_ro_array<ArchivedKlassSubGraphInfoRecord>(num_records);

  KlassSubGraphInfo* info = _subgraph_info_list;

  int i = 0;

  while (info != NULL) {

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

    ArchivedKlassSubGraphInfoRecord* record =

      _archived_subgraph_info_records->adr_at(i);

    record->init(info);

    info = info->next();

    i ++;

  }

  // _subgraph_info_list is no longer needed

  delete _subgraph_info_list;

  _subgraph_info_list = NULL;

  char* end_p = MetaspaceShared::read_only_space_top();

  size_t records_size = end_p - start_p;

  return records_size;

}

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

void HeapShared::write_archived_subgraph_infos() {

  assert(DumpSharedSpaces, "dump time only");

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

  _num_archived_subgraph_info_records = num_of_subgraph_infos();

  size_t records_size = build_archived_subgraph_info_records(

                             _num_archived_subgraph_info_records);

  // Now write the header information:

  // records_size, num_records, _archived_subgraph_info_records

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

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

  *p = (intptr_t)records_size;

  p ++;

  *p = (intptr_t)_num_archived_subgraph_info_records;

  p ++;

  *p = (intptr_t)_archived_subgraph_info_records;

}

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

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

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

  size_t records_size = (size_t)(*p);

  p ++;

  _num_archived_subgraph_info_records = *p;

  p ++;

  _archived_subgraph_info_records =

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

  buffer = (char*)_archived_subgraph_info_records + records_size;

  return buffer;

}

void HeapShared::initialize_from_archived_subgraph(Klass* k) {

  if (!MetaspaceShared::open_archive_heap_region_mapped()) {

    return; // nothing to do

  }

  if (_num_archived_subgraph_info_records == 0) {

    return; // no subgraph info records

  }

  // Initialize from archived data. Currently this is done only

  // during VM initialization time. No lock is needed.

  Thread* THREAD = Thread::current();

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

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

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

      int i;

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

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

      // NULL class loader is used.

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

      if (klasses != NULL) {

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

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

          Klass* resolved_k = SystemDictionary::resolve_or_null(

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

          if (resolved_k != obj_k) {

            return;

          }

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

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

            ik->initialize(THREAD);

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

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

            oak->initialize(THREAD);

          }

        }

      }

      if (HAS_PENDING_EXCEPTION) {

        CLEAR_PENDING_EXCEPTION;

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

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

        // subgraphs referenced from k in this case.

        return;

      }

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

      // the corresponding fields within the mirror.

      oop m = k->java_mirror();

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

      if (entry_field_records != NULL) {

        int efr_len = entry_field_records->length();

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

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

          int field_offset = entry_field_records->at(i);

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

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

          // also 'known' by GC.

          oop v = MetaspaceShared::materialize_archived_object(

            entry_field_records->at(i+1));

          m->obj_field_put(field_offset, v);

          i += 2;

        }

      }

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

      // mirror after this point.

      return;

    }

  }

}

class WalkOopAndArchiveClosure: public BasicOopIterateClosure {

  int _level;

  bool _record_klasses_only;

  KlassSubGraphInfo* _subgraph_info;

  oop _orig_referencing_obj;

  oop _archived_referencing_obj;

  Thread* _thread;

 public:

  WalkOopAndArchiveClosure(int level, bool record_klasses_only,

                           KlassSubGraphInfo* subgraph_info,

                           oop orig, oop archived, TRAPS) :

    _level(level), _record_klasses_only(record_klasses_only),

    _subgraph_info(subgraph_info),

    _orig_referencing_obj(orig), _archived_referencing_obj(archived),

    _thread(THREAD) {}

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

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

 protected:

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

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

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

      assert(!MetaspaceShared::is_archive_object(obj),

             "original objects must not point to archived objects");

      size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));

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

      Thread* THREAD = _thread;

      if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {

        ResourceMark rm;

        log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,

                             _orig_referencing_obj->klass()->external_name(), field_delta,

                             p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());

        LogTarget(Trace, cds, heap) log;

        LogStream out(log);

        obj->print_on(&out);

      }

      oop archived = HeapShared::archive_reachable_objects_from(_level + 1, _subgraph_info, obj, THREAD);

      assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");

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

      if (!_record_klasses_only) {

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

        log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,

                             _level, p2i(new_p), p2i(obj), p2i(archived));

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

      }

    }

  }

};

// (1) If orig_obj has not been archived yet, archive it.

// (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),

//     trace all  objects that are reachable from it, and make sure these objects are archived.

// (3) Record the klasses of all orig_obj and all reachable objects.

oop HeapShared::archive_reachable_objects_from(int level, KlassSubGraphInfo* subgraph_info, oop orig_obj, TRAPS) {

  assert(orig_obj != NULL, "must be");

  assert(!MetaspaceShared::is_archive_object(orig_obj), "sanity");

  // java.lang.Class instances cannot be included in an archived

  // object sub-graph.

  if (java_lang_Class::is_instance(orig_obj)) {

    log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);

    vm_exit(1);

  }

  oop archived_obj = MetaspaceShared::find_archived_heap_object(orig_obj);

  if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {

    // To save time, don't walk strings that are already archived. They just contain

    // pointers to a type array, whose klass doesn't need to be recorded.

    return archived_obj;

  }

  if (has_been_seen_during_subgraph_recording(orig_obj)) {

    // orig_obj has already been archived and traced. Nothing more to do.

    return archived_obj;

  } else {

    set_has_been_seen_during_subgraph_recording(orig_obj);

  }

  bool record_klasses_only = (archived_obj != NULL);

  if (archived_obj == NULL) {

    ++_num_new_archived_objs;

    archived_obj = MetaspaceShared::archive_heap_object(orig_obj, THREAD);

    if (archived_obj == NULL) {

      // Skip archiving the sub-graph referenced from the current entry field.

      ResourceMark rm;

      log_error(cds, heap)(

        "Cannot archive the sub-graph referenced from %s object ("

        PTR_FORMAT ") size %d, skipped.",

        orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);

      if (level == 1) {

        // Don't archive a subgraph root that's too big. For archives static fields, that's OK

        // as the Java code will take care of initializing this field dynamically.

        return NULL;

      } else {

        // We don't know how to handle an object that has been archived, but some of its reachable

        // objects cannot be archived. Bail out for now. We might need to fix this in the future if

        // we have a real use case.

        vm_exit(1);

      }

    }

  }

  assert(archived_obj != NULL, "must be");

  Klass *orig_k = orig_obj->klass();

  Klass *relocated_k = archived_obj->klass();

  subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);

  WalkOopAndArchiveClosure walker(level, record_klasses_only, subgraph_info, orig_obj, archived_obj, THREAD);

  orig_obj->oop_iterate(&walker);

  return archived_obj;

}

//

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

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

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

// Sub-graph archiving restrictions (current):

//

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

//   entry class) must be boot class only.

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

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

//

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

// WalkOopAndArchiveClosure):

//

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

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

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

// the next step.

//

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

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

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

// Otherwise, proceed to the next step.

//

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

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

//

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

// point to the current archived object.

//

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

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

// be accessed at runtime.

//

void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,

                                                             const char* klass_name,

                                                             int field_offset,

                                                             const char* field_name,

                                                             TRAPS) {

  assert(DumpSharedSpaces, "dump time only");

  assert(k->is_shared_boot_class(), "must be boot class");

  oop m = k->java_mirror();

  oop archived_m = MetaspaceShared::find_archived_heap_object(m);

  if (CompressedOops::is_null(archived_m)) {

    return;

  }

  KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);

  oop f = m->obj_field(field_offset);

  log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));

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

    if (log_is_enabled(Trace, cds, heap)) {

      LogTarget(Trace, cds, heap) log;

      LogStream out(log);