systemDictionaryShared.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * 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.
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#ifndef SHARE_CLASSFILE_SYSTEMDICTIONARYSHARED_HPP
#define SHARE_CLASSFILE_SYSTEMDICTIONARYSHARED_HPP

#include "oops/klass.hpp"
#include "classfile/dictionary.hpp"
#include "classfile/packageEntry.hpp"
#include "classfile/systemDictionary.hpp"
#include "memory/filemap.hpp"


/*===============================================================================

    Handling of the classes in the AppCDS archive

    To ensure safety and to simplify the implementation, archived classes are
    "segregated" into 2 types. The following rules describe how they
    are stored and looked up.

[1] Category of archived classes

    There are 2 disjoint groups of classes stored in the AppCDS archive:

    BUILTIN:              These classes may be defined ONLY by the BOOT/PLATFORM/APP
                          loaders.

    UNREGISTERED:         These classes may be defined ONLY by a ClassLoader
                          instance that's not listed above (using fingerprint matching)

[2] How classes from different categories are specified in the classlist:

    Starting from JDK9, each class in the classlist may be specified with
    these keywords: "id", "super", "interfaces", "loader" and "source".


    BUILTIN               Only the "id" keyword may be (optionally) specified. All other
                          keywords are forbidden.

                          The named class is looked up from the jimage and from
                          Xbootclasspath/a and CLASSPATH.

    UNREGISTERED:         The "id", "super", and "source" keywords must all be
                          specified.

                          The "interfaces" keyword must be specified if the class implements
                          one or more local interfaces. The "interfaces" keyword must not be
                          specified if the class does not implement local interfaces.

                          The named class is looked up from the location specified in the
                          "source" keyword.

    Example classlist:

    # BUILTIN
    java/lang/Object id: 0
    java/lang/Cloneable id: 1
    java/lang/String

    # UNREGISTERED
    Bar id: 3 super: 0 interfaces: 1 source: /foo.jar


[3] Identifying the category of archived classes

    BUILTIN:              (C->shared_classpath_index() >= 0)
    UNREGISTERED:         (C->shared_classpath_index() == UNREGISTERED_INDEX (-9999))

[4] Lookup of archived classes at run time:

    (a) BUILTIN loaders:

        search _builtin_dictionary

    (b) UNREGISTERED loaders:

        search _unregistered_dictionary for an entry that matches the
        (name, clsfile_len, clsfile_crc32).

===============================================================================*/
#define UNREGISTERED_INDEX -9999

class ClassFileStream;
class DumpTimeSharedClassInfo;
class DumpTimeSharedClassTable;
class RunTimeSharedClassInfo;
class RunTimeSharedDictionary;

class SystemDictionaryShared: public SystemDictionary {
  friend class ExcludeDumpTimeSharedClasses;
public:
  enum {
    FROM_FIELD_IS_PROTECTED = 1 << 0,
    FROM_IS_ARRAY           = 1 << 1,
    FROM_IS_OBJECT          = 1 << 2
  };

private:
  // These _shared_xxxs arrays are used to initialize the java.lang.Package and
  // java.security.ProtectionDomain objects associated with each shared class.
  //
  // See SystemDictionaryShared::init_security_info for more info.
  static objArrayOop _shared_protection_domains;
  static objArrayOop _shared_jar_urls;
  static objArrayOop _shared_jar_manifests;

  static InstanceKlass* load_shared_class_for_builtin_loader(
                                               Symbol* class_name,
                                               Handle class_loader,
                                               TRAPS);
  static Handle get_package_name(Symbol*  class_name, TRAPS);


  // Package handling:
  //
  // 1. For named modules in the runtime image
  //    BOOT classes: Reuses the existing JVM_GetSystemPackage(s) interfaces
  //                  to get packages in named modules for shared classes.
  //                  Package for non-shared classes in named module is also
  //                  handled using JVM_GetSystemPackage(s).
  //
  //    APP  classes: VM calls ClassLoaders.AppClassLoader::definePackage(String, Module)
  //                  to define package for shared app classes from named
  //                  modules.
  //
  //    PLATFORM  classes: VM calls ClassLoaders.PlatformClassLoader::definePackage(String, Module)
  //                  to define package for shared platform classes from named
  //                  modules.
  //
  // 2. For unnamed modules
  //    BOOT classes: Reuses the existing JVM_GetSystemPackage(s) interfaces to
  //                  get packages for shared boot classes in unnamed modules.
  //
  //    APP  classes: VM calls ClassLoaders.AppClassLoader::defineOrCheckPackage()
  //                  with with the manifest and url from archived data.
  //
  //    PLATFORM  classes: No package is defined.
  //
  // The following two define_shared_package() functions are used to define
  // package for shared APP and PLATFORM classes.
  static void define_shared_package(Symbol*  class_name,
                                    Handle class_loader,
                                    Handle manifest,
                                    Handle url,
                                    TRAPS);
  static void define_shared_package(Symbol* class_name,
                                    Handle class_loader,
                                    ModuleEntry* mod_entry,
                                    TRAPS);

  static Handle get_shared_jar_manifest(int shared_path_index, TRAPS);
  static Handle get_shared_jar_url(int shared_path_index, TRAPS);
  static Handle get_protection_domain_from_classloader(Handle class_loader,
                                                       Handle url, TRAPS);
  static Handle get_shared_protection_domain(Handle class_loader,
                                             int shared_path_index,
                                             Handle url,
                                             TRAPS);
  static Handle get_shared_protection_domain(Handle class_loader,
                                             ModuleEntry* mod, TRAPS);
  static Handle init_security_info(Handle class_loader, InstanceKlass* ik, TRAPS);

  static void atomic_set_array_index(objArrayOop array, int index, oop o) {
    // Benign race condition:  array.obj_at(index) may already be filled in.
    // The important thing here is that all threads pick up the same result.
    // It doesn't matter which racing thread wins, as long as only one
    // result is used by all threads, and all future queries.
    array->atomic_compare_exchange_oop(index, o, NULL);
  }

  static oop shared_protection_domain(int index);
  static void atomic_set_shared_protection_domain(int index, oop pd) {
    atomic_set_array_index(_shared_protection_domains, index, pd);
  }
  static void allocate_shared_protection_domain_array(int size, TRAPS);
  static oop shared_jar_url(int index);
  static void atomic_set_shared_jar_url(int index, oop url) {
    atomic_set_array_index(_shared_jar_urls, index, url);
  }
  static void allocate_shared_jar_url_array(int size, TRAPS);
  static oop shared_jar_manifest(int index);
  static void atomic_set_shared_jar_manifest(int index, oop man) {
    atomic_set_array_index(_shared_jar_manifests, index, man);
  }
  static void allocate_shared_jar_manifest_array(int size, TRAPS);
  static InstanceKlass* acquire_class_for_current_thread(
                                 InstanceKlass *ik,
                                 Handle class_loader,
                                 Handle protection_domain,
                                 const ClassFileStream* cfs,
                                 TRAPS);
  static DumpTimeSharedClassInfo* find_or_allocate_info_for(InstanceKlass* k);
  static void write_dictionary(RunTimeSharedDictionary* dictionary,
                               bool is_builtin,
                               bool is_static_archive = true);
  static bool is_jfr_event_class(InstanceKlass *k);
  static void warn_excluded(InstanceKlass* k, const char* reason);
  static bool should_be_excluded(InstanceKlass* k);

  DEBUG_ONLY(static bool _no_class_loading_should_happen;)
public:
  static InstanceKlass* find_builtin_class(Symbol* class_name);

  static const RunTimeSharedClassInfo* find_record(RunTimeSharedDictionary* static_dict,
                                                   RunTimeSharedDictionary* dynamic_dict,
                                                   Symbol* name);

  static bool has_platform_or_app_classes();

  // Called by PLATFORM/APP loader only
  static InstanceKlass* find_or_load_shared_class(Symbol* class_name,
                                               Handle class_loader,
                                               TRAPS);


  static void allocate_shared_data_arrays(int size, TRAPS);
  static void oops_do(OopClosure* f);

  // Check if sharing is supported for the class loader.
  static bool is_sharing_possible(ClassLoaderData* loader_data);
  static bool is_shared_class_visible_for_classloader(InstanceKlass* ik,
                                                      Handle class_loader,
                                                      Symbol* pkg_name,
                                                      PackageEntry* pkg_entry,
                                                      ModuleEntry* mod_entry,
                                                      TRAPS);
  static PackageEntry* get_package_entry(Symbol* pkg,
                                         ClassLoaderData *loader_data) {
    if (loader_data != NULL) {
      PackageEntryTable* pkgEntryTable = loader_data->packages();
      return pkgEntryTable->lookup_only(pkg);
    }
    return NULL;
  }

  static bool add_unregistered_class(InstanceKlass* k, TRAPS);
  static InstanceKlass* dump_time_resolve_super_or_fail(Symbol* child_name,
                                                Symbol* class_name,
                                                Handle class_loader,
                                                Handle protection_domain,
                                                bool is_superclass,
                                                TRAPS);

  static void init_dumptime_info(InstanceKlass* k) NOT_CDS_RETURN;
  static void remove_dumptime_info(InstanceKlass* k) NOT_CDS_RETURN;

  static Dictionary* boot_loader_dictionary() {
    return ClassLoaderData::the_null_class_loader_data()->dictionary();
  }

  static void update_shared_entry(InstanceKlass* klass, int id);
  static void set_shared_class_misc_info(InstanceKlass* k, ClassFileStream* cfs);

  static InstanceKlass* lookup_from_stream(Symbol* class_name,
                                           Handle class_loader,
                                           Handle protection_domain,
                                           const ClassFileStream* st,
                                           TRAPS);
  // "verification_constraints" are a set of checks performed by
  // VerificationType::is_reference_assignable_from when verifying a shared class during
  // dump time.
  //
  // With AppCDS, it is possible to override archived classes by calling
  // ClassLoader.defineClass() directly. SystemDictionary::load_shared_class() already
  // ensures that you cannot load a shared class if its super type(s) are changed. However,
  // we need an additional check to ensure that the verification_constraints did not change
  // between dump time and runtime.
  static bool add_verification_constraint(InstanceKlass* k, Symbol* name,
                  Symbol* from_name, bool from_field_is_protected,
                  bool from_is_array, bool from_is_object) NOT_CDS_RETURN_(false);
  static void check_verification_constraints(InstanceKlass* klass,
                                             TRAPS) NOT_CDS_RETURN;
  static bool is_builtin(InstanceKlass* k) {
    return (k->shared_classpath_index() != UNREGISTERED_INDEX);
  }
  static void check_excluded_classes();
  static void validate_before_archiving(InstanceKlass* k);
  static bool is_excluded_class(InstanceKlass* k);
  static void dumptime_classes_do(class MetaspaceClosure* it);
  static size_t estimate_size_for_archive();
  static void write_to_archive(bool is_static_archive = true);
  static void serialize_dictionary_headers(class SerializeClosure* soc,
                                           bool is_static_archive = true);
  static void serialize_well_known_klasses(class SerializeClosure* soc);
  static void print() { return print_on(tty); }
  static void print_on(outputStream* st) NOT_CDS_RETURN;
  static void print_table_statistics(outputStream* st) NOT_CDS_RETURN;
  static bool empty_dumptime_table() NOT_CDS_RETURN_(true);

  DEBUG_ONLY(static bool no_class_loading_should_happen() {return _no_class_loading_should_happen;})

#ifdef ASSERT
  class NoClassLoadingMark: public StackObj {
  public:
    NoClassLoadingMark() {
      assert(!_no_class_loading_should_happen, "must not be nested");
      _no_class_loading_should_happen = true;
    }
    ~NoClassLoadingMark() {
      _no_class_loading_should_happen = false;
    }
  };
#endif

  template <typename T>
  static unsigned int hash_for_shared_dictionary(T* ptr) {
    assert(ptr > (T*)SharedBaseAddress, "must be");
    address p = address(ptr) - SharedBaseAddress;
    return primitive_hash<address>(p);
  }
};

#endif // SHARE_CLASSFILE_SYSTEMDICTIONARYSHARED_HPP