8249262: Initialize InstanceKlass::_package_entry during CDS dump time

Reviewed-by: iklam, minqi

src/hotspot/share/classfile/classLoaderDataShared.cpp

@@ -1,5 +1,5 @@
  /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, 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
@@ -33,6 +33,8 @@
 
 #if INCLUDE_CDS_JAVA_HEAP
 
+bool ClassLoaderDataShared::_full_module_graph_loaded = false;
+
 class ArchivedClassLoaderData {
   Array<PackageEntry*>* _packages;
   Array<ModuleEntry*>* _modules;
@@ -214,6 +216,7 @@ void ClassLoaderDataShared::restore_java_platform_loader_from_archive(ClassLoade
 void ClassLoaderDataShared::restore_java_system_loader_from_archive(ClassLoaderData* loader_data) {
   assert(UseSharedSpaces && MetaspaceShared::use_full_module_graph(), "must be");
   _archived_system_loader_data.restore(loader_data, true, true);
+  _full_module_graph_loaded = true;
 }
 
 #endif // INCLUDE_CDS_JAVA_HEAP

src/hotspot/share/classfile/classLoaderDataShared.hpp

@@ -1,5 +1,5 @@
  /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, 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
@@ -33,6 +33,7 @@ class MetaspaceClosure;
 class SerializeClosure;
 
 class ClassLoaderDataShared : AllStatic {
+  static bool _full_module_graph_loaded;
 public:
   static void allocate_archived_tables();
   static void iterate_symbols(MetaspaceClosure* closure);
@@ -43,6 +44,7 @@ public:
   static oop  restore_archived_oops_for_null_class_loader_data();
   static void restore_java_platform_loader_from_archive(ClassLoaderData* loader_data);
   static void restore_java_system_loader_from_archive(ClassLoaderData* loader_data);
+  static bool is_full_module_graph_loaded() { return _full_module_graph_loaded; }
 };
 
 #endif // SHARE_CLASSFILE_CLASSLOADERDATASHARED_HPP

src/hotspot/share/classfile/packageEntry.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2021, 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
@@ -222,8 +222,11 @@ PackageEntry* PackageEntry::allocate_archived_entry() const {
 
 PackageEntry* PackageEntry::get_archived_entry(PackageEntry* orig_entry) {
   PackageEntry** ptr = _archived_packages_entries->get(orig_entry);
-  assert(ptr != NULL && *ptr != NULL, "must have been allocated");
-  return *ptr;
+  if (ptr != NULL) {
+    return *ptr;
+  } else {
+    return NULL;
+  }
 }
 
 void PackageEntry::iterate_symbols(MetaspaceClosure* closure) {

src/hotspot/share/classfile/systemDictionaryShared.cpp

@@ -1053,11 +1053,19 @@ InstanceKlass* SystemDictionaryShared::find_or_load_shared_class(
   return k;
 }
 
-PackageEntry* SystemDictionaryShared::get_package_entry_from_class_name(Handle class_loader, Symbol* class_name) {
-  PackageEntry* pkg_entry = NULL;
-  TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
+PackageEntry* SystemDictionaryShared::get_package_entry_from_class(InstanceKlass* ik, Handle class_loader) {
+  PackageEntry* pkg_entry = ik->package();
+  if (MetaspaceShared::use_full_module_graph() && ik->is_shared() && pkg_entry != NULL) {
+    assert(MetaspaceShared::is_in_shared_metaspace(pkg_entry), "must be");
+    assert(!ik->is_shared_unregistered_class(), "unexpected archived package entry for an unregistered class");
+    assert(ik->module()->is_named(), "unexpected archived package entry for a class in an unnamed module");
+    return pkg_entry;
+  }
+  TempNewSymbol pkg_name = ClassLoader::package_from_class_name(ik->name());
   if (pkg_name != NULL) {
     pkg_entry = class_loader_data(class_loader)->packages()->lookup_only(pkg_name);
+  } else {
+    pkg_entry = NULL;
   }
   return pkg_entry;
 }
@@ -1072,7 +1080,7 @@ InstanceKlass* SystemDictionaryShared::load_shared_class_for_builtin_loader(
          SystemDictionary::is_system_class_loader(class_loader()))  ||
         (ik->is_shared_platform_class() &&
          SystemDictionary::is_platform_class_loader(class_loader()))) {
-      PackageEntry* pkg_entry = get_package_entry_from_class_name(class_loader, class_name);
+      PackageEntry* pkg_entry = get_package_entry_from_class(ik, class_loader);
       Handle protection_domain =
         SystemDictionaryShared::init_security_info(class_loader, ik, pkg_entry, CHECK_NULL);
       return load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, THREAD);
@@ -1172,7 +1180,7 @@ InstanceKlass* SystemDictionaryShared::acquire_class_for_current_thread(
   loader_data->add_class(ik);
 
   // Get the package entry.
-  PackageEntry* pkg_entry = get_package_entry_from_class_name(class_loader, ik->name());
+  PackageEntry* pkg_entry = get_package_entry_from_class(ik, class_loader);
 
   // Load and check super/interfaces, restore unsharable info
   InstanceKlass* shared_klass = load_shared_class(ik, class_loader, protection_domain,
@@ -1684,7 +1692,7 @@ InstanceKlass* SystemDictionaryShared::prepare_shared_lambda_proxy_class(Instanc
                                                                          InstanceKlass* caller_ik, TRAPS) {
   Handle class_loader(THREAD, caller_ik->class_loader());
   Handle protection_domain;
-  PackageEntry* pkg_entry = get_package_entry_from_class_name(class_loader, caller_ik->name());
+  PackageEntry* pkg_entry = get_package_entry_from_class(caller_ik, class_loader);
   if (caller_ik->class_loader() != NULL) {
     protection_domain = SystemDictionaryShared::init_security_info(class_loader, caller_ik, pkg_entry, CHECK_NULL);
   }

src/hotspot/share/classfile/systemDictionaryShared.hpp

@@ -135,7 +135,7 @@ private:
                                                TRAPS);
   static Handle get_package_name(Symbol*  class_name, TRAPS);
 
-  static PackageEntry* get_package_entry_from_class_name(Handle class_loader, Symbol* class_name);
+  static PackageEntry* get_package_entry_from_class(InstanceKlass* ik, Handle class_loader);
 
 
   // Package handling:

src/hotspot/share/memory/metaspaceShared.cpp

@@ -1846,6 +1846,11 @@ intx MetaspaceShared::final_delta() {
 }
 
 bool MetaspaceShared::use_full_module_graph() {
+#if INCLUDE_CDS_JAVA_HEAP
+  if (ClassLoaderDataShared::is_full_module_graph_loaded()) {
+    return true;
+  }
+#endif
   bool result = _use_optimized_module_handling && _use_full_module_graph &&
     (UseSharedSpaces || DumpSharedSpaces) && HeapShared::is_heap_object_archiving_allowed();
   if (result && UseSharedSpaces) {

src/hotspot/share/oops/instanceKlass.cpp

@@ -2538,7 +2538,7 @@ void InstanceKlass::remove_unshareable_info() {
   _oop_map_cache = NULL;
   // clear _nest_host to ensure re-load at runtime
   _nest_host = NULL;
-  _package_entry = NULL;
+  init_shared_package_entry();
   _dep_context_last_cleaned = 0;
 }
 
@@ -2551,6 +2551,27 @@ void InstanceKlass::remove_java_mirror() {
   }
 }
 
+void InstanceKlass::init_shared_package_entry() {
+#if !INCLUDE_CDS_JAVA_HEAP
+  _package_entry = NULL;
+#else
+  if (!MetaspaceShared::use_full_module_graph()) {
+    _package_entry = NULL;
+  } else if (DynamicDumpSharedSpaces) {
+    if (!MetaspaceShared::is_in_shared_metaspace(_package_entry)) {
+      _package_entry = NULL;
+    }
+  } else {
+    if (is_shared_unregistered_class()) {
+      _package_entry = NULL;
+    } else {
+      _package_entry = PackageEntry::get_archived_entry(_package_entry);
+    }
+  }
+  ArchivePtrMarker::mark_pointer((address**)&_package_entry);
+#endif
+}
+
 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain,
                                              PackageEntry* pkg_entry, TRAPS) {
   // SystemDictionary::add_to_hierarchy() sets the init_state to loaded
@@ -2834,6 +2855,15 @@ void InstanceKlass::set_package(ClassLoaderData* loader_data, PackageEntry* pkg_
     check_prohibited_package(name(), loader_data, CHECK);
   }
 
+  if (is_shared() && _package_entry == pkg_entry) {
+    if (MetaspaceShared::use_full_module_graph()) {
+      // we can use the saved package
+      return;
+    } else {
+      _package_entry = NULL;
+    }
+  }
+
   // ClassLoader::package_from_class_name has already incremented the refcount of the symbol
   // it returns, so we need to decrement it when the current function exits.
   TempNewSymbol from_class_name =