/* * Copyright (c) 2016, 2022, 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. *
*/
void ModuleEntry::set_location(Symbol* location) { // _location symbol's refcounts are managed by ModuleEntry, // must decrement the old one before updating.
Symbol::maybe_decrement_refcount(_location);
// Return true if the module's version should be displayed in error messages, // logging, etc. // Return false if the module's version is null, if it is unnamed, or if the // module is not an upgradeable module. // Detect if the module is not upgradeable by checking: // 1. Module location is "jrt:/java." and its loader is boot or platform // 2. Module location is "jrt:/jdk.", its loader is one of the builtin loaders // and its version is the same as module java.base's version // The above check is imprecise but should work in almost all cases. bool ModuleEntry::should_show_version() { if (version() == NULL || !is_named()) returnfalse;
if (location() != NULL) {
ResourceMark rm; constchar* loc = location()->as_C_string();
ClassLoaderData* cld = loader_data();
assert(!cld->has_class_mirror_holder(), "module's cld should have a ClassLoader holder not a Class holder"); if ((cld->is_the_null_class_loader_data() || cld->is_platform_class_loader_data()) &&
(strncmp(loc, "jrt:/java.", 10) == 0)) { returnfalse;
} if ((ModuleEntryTable::javabase_moduleEntry()->version()->fast_compare(version()) == 0) &&
cld->is_permanent_class_loader_data() && (strncmp(loc, "jrt:/jdk.", 9) == 0)) { returnfalse;
}
} returntrue;
}
void ModuleEntry::set_version(Symbol* version) { // _version symbol's refcounts are managed by ModuleEntry, // must decrement the old one before updating.
Symbol::maybe_decrement_refcount(_version);
// Set the shared ProtectionDomain atomically void ModuleEntry::set_shared_protection_domain(ClassLoaderData *loader_data,
Handle pd_h) { // Create a handle for the shared ProtectionDomain and save it atomically. // init_handle_locked checks if someone beats us setting the _shared_pd cache.
loader_data->init_handle_locked(_shared_pd, pd_h);
}
// Returns true if this module can read module m bool ModuleEntry::can_read(ModuleEntry* m) const {
assert(m != NULL, "No module to lookup in this module's reads list");
// Unnamed modules read everyone and all modules // read java.base. If either of these conditions // hold, readability has been established. if (!this->is_named() ||
(m == ModuleEntryTable::javabase_moduleEntry())) { returntrue;
}
MutexLocker m1(Module_lock); // This is a guard against possible race between agent threads that redefine // or retransform classes in this module. Only one of them is adding the // default read edges to the unnamed modules of the boot and app class loaders // with an upcall to jdk.internal.module.Modules.transformedByAgent. // At the same time, another thread can instrument the module classes by // injecting dependencies that require the default read edges for resolution. if (this->has_default_read_edges() && !m->is_named()) {
ClassLoaderData* cld = m->loader_data();
assert(!cld->has_class_mirror_holder(), "module's cld should have a ClassLoader holder not a Class holder"); if (cld->is_the_null_class_loader_data() || cld->is_system_class_loader_data()) { returntrue; // default read edge
}
} if (!has_reads_list()) { returnfalse;
} else { return _reads->contains(m);
}
}
// Add a new module to this module's reads list void ModuleEntry::add_read(ModuleEntry* m) { // Unnamed module is special cased and can read all modules if (!is_named()) { return;
}
MutexLocker m1(Module_lock); if (m == NULL) {
set_can_read_all_unnamed();
} else { if (_reads == NULL) { // Lazily create a module's reads list
_reads = new (mtModule) GrowableArray<ModuleEntry*>(MODULE_READS_SIZE, mtModule);
}
// Determine, based on this newly established read edge to module m, // if this module's read list should be walked at a GC safepoint.
set_read_walk_required(m->loader_data());
// Establish readability to module m
_reads->append_if_missing(m);
}
}
// If the module's loader, that a read edge is being established to, is // not the same loader as this module's and is not one of the 3 builtin // class loaders, then this module's reads list must be walked at GC // safepoint. Modules have the same life cycle as their defining class // loaders and should be removed if dead. void ModuleEntry::set_read_walk_required(ClassLoaderData* m_loader_data) {
assert(is_named(), "Cannot call set_read_walk_required on unnamed module");
assert_locked_or_safepoint(Module_lock); if (!_must_walk_reads &&
loader_data() != m_loader_data &&
!m_loader_data->is_builtin_class_loader_data()) {
_must_walk_reads = true; if (log_is_enabled(Trace, module)) {
ResourceMark rm;
log_trace(module)("ModuleEntry::set_read_walk_required(): module %s reads list must be walked",
(name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE);
}
}
}
// Set whether the module is open, i.e. all its packages are unqualifiedly exported void ModuleEntry::set_is_open(bool is_open) {
assert_lock_strong(Module_lock);
_is_open = is_open;
}
// Returns true if the module has a non-empty reads list. As such, the unnamed // module will return false. bool ModuleEntry::has_reads_list() const {
assert_locked_or_safepoint(Module_lock); return ((_reads != NULL) && !_reads->is_empty());
}
// Purge dead module entries out of reads list. void ModuleEntry::purge_reads() {
assert_locked_or_safepoint(Module_lock);
if (_must_walk_reads && has_reads_list()) { // This module's _must_walk_reads flag will be reset based // on the remaining live modules on the reads list.
_must_walk_reads = false;
if (log_is_enabled(Trace, module)) {
ResourceMark rm;
log_trace(module)("ModuleEntry::purge_reads(): module %s reads list being walked",
(name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE);
}
// Go backwards because this removes entries that are dead. int len = _reads->length(); for (int idx = len - 1; idx >= 0; idx--) {
ModuleEntry* module_idx = _reads->at(idx);
ClassLoaderData* cld_idx = module_idx->loader_data(); if (cld_idx->is_unloading()) {
_reads->delete_at(idx);
} else { // Update the need to walk this module's reads based on live modules
set_read_walk_required(cld_idx);
}
}
}
}
// Initialize fields specific to a ModuleEntry if (_name == nullptr) { // Unnamed modules can read all other unnamed modules.
set_can_read_all_unnamed();
} else {
_name->increment_refcount();
}
if (!module_handle.is_null()) {
_module = loader_data->add_handle(module_handle);
}
set_version(version);
// may need to add CDS info
set_location(location);
if (name != nullptr && ClassLoader::is_in_patch_mod_entries(name)) {
set_is_patched(); if (log_is_enabled(Trace, module, patch)) {
ResourceMark rm;
log_trace(module, patch)("Marked module %s as patched from --patch-module",
name != NULL ? name->as_C_string() : UNNAMED_MODULE);
}
}
JFR_ONLY(INIT_ID(this);)
}
ModuleEntry::~ModuleEntry() { // Clean out the C heap allocated reads list first before freeing the entry
delete_reads();
Symbol::maybe_decrement_refcount(_name);
Symbol::maybe_decrement_refcount(_version);
Symbol::maybe_decrement_refcount(_location);
}
ModuleEntry* ModuleEntry::create_unnamed_module(ClassLoaderData* cld) { // The java.lang.Module for this loader's // corresponding unnamed module can be found in the java.lang.ClassLoader object.
oop module = java_lang_ClassLoader::unnamedModule(cld->class_loader());
// Ensure that the unnamed module was correctly set when the class loader was constructed. // Guarantee will cause a recognizable crash if the user code has circumvented calling the ClassLoader constructor.
ResourceMark rm;
guarantee(java_lang_Module::is_instance(module), "The unnamed module for ClassLoader %s, is null or not an instance of java.lang.Module. The class loader has not been initialized correctly.",
cld->loader_name_and_id());
// Store pointer to the ModuleEntry in the unnamed module's java.lang.Module object.
java_lang_Module::set_module_entry(module, unnamed_module);
return unnamed_module;
}
ModuleEntry* ModuleEntry::create_boot_unnamed_module(ClassLoaderData* cld) { // For the boot loader, the java.lang.Module for the unnamed module // is not known until a call to JVM_SetBootLoaderUnnamedModule is made. At // this point initially create the ModuleEntry for the unnamed module.
ModuleEntry* unnamed_module = new_unnamed_module_entry(Handle(), cld);
assert(unnamed_module != NULL, "boot loader unnamed module should not be null"); return unnamed_module;
}
// When creating an unnamed module, this is called without holding the Module_lock. // This is okay because the unnamed module gets created before the ClassLoaderData // is available to other threads.
ModuleEntry* ModuleEntry::new_unnamed_module_entry(Handle module_handle, ClassLoaderData* cld) {
ModuleEntry* entry = new ModuleEntry(module_handle, /*is_open*/true, /*name*/nullptr, /*version*/ nullptr, /*location*/ nullptr,
cld); // Unnamed modules can read all other unnamed modules.
assert(entry->can_read_all_unnamed(), "constructor set that"); return entry;
}
#if INCLUDE_CDS_JAVA_HEAP typedef ResourceHashtable< const ModuleEntry*,
ModuleEntry*,
557, // prime number
AnyObj::C_HEAP> ArchivedModuleEntries; static ArchivedModuleEntries* _archive_modules_entries = NULL;
ModuleEntry* ModuleEntry::allocate_archived_entry() const {
assert(is_named(), "unnamed packages/modules are not archived");
ModuleEntry* archived_entry = (ModuleEntry*)ArchiveBuilder::rw_region_alloc(sizeof(ModuleEntry));
memcpy((void*)archived_entry, (void*)this, sizeof(ModuleEntry));
if (_archive_modules_entries == NULL) {
_archive_modules_entries = new (mtClass)ArchivedModuleEntries();
}
assert(_archive_modules_entries->get(this) == NULL, "Each ModuleEntry must not be shared across ModuleEntryTables");
_archive_modules_entries->put(this, archived_entry);
// This function is used to archive ModuleEntry::_reads and PackageEntry::_qualified_exports. // GrowableArray cannot be directly archived, as it needs to be expandable at runtime. // Write it out as an Array, and convert it back to GrowableArray at runtime.
Array<ModuleEntry*>* ModuleEntry::write_growable_array(GrowableArray<ModuleEntry*>* array) {
Array<ModuleEntry*>* archived_array = NULL; int length = (array == NULL) ? 0 : array->length(); if (length > 0) {
archived_array = ArchiveBuilder::new_ro_array<ModuleEntry*>(length); for (int i = 0; i < length; i++) {
ModuleEntry* archived_entry = get_archived_entry(array->at(i));
archived_array->at_put(i, archived_entry);
ArchivePtrMarker::mark_pointer((address*)archived_array->adr_at(i));
}
}
return archived_array;
}
GrowableArray<ModuleEntry*>* ModuleEntry::restore_growable_array(Array<ModuleEntry*>* archived_array) {
GrowableArray<ModuleEntry*>* array = NULL; int length = (archived_array == NULL) ? 0 : archived_array->length(); if (length > 0) {
array = new (mtModule) GrowableArray<ModuleEntry*>(length, mtModule); for (int i = 0; i < length; i++) {
ModuleEntry* archived_entry = archived_array->at(i);
array->append(archived_entry);
}
}
// This was cleared to zero during dump time -- we didn't save the value // because it may be affected by archive relocation.
java_lang_Module::set_module_entry(module_handle(), this);
if (loader_data->class_loader() != NULL) {
java_lang_Module::set_loader(module_handle(), loader_data->class_loader());
}
}
staticint compare_module_by_name(ModuleEntry* a, ModuleEntry* b) {
assert(a == b || a->name() != b->name(), "no duplicated names"); return a->name()->fast_compare(b->name());
}
void ModuleEntryTable::iterate_symbols(MetaspaceClosure* closure) { auto syms = [&] (const SymbolHandle& key, ModuleEntry*& m) {
m->iterate_symbols(closure);
};
_table.iterate_all(syms);
}
Array<ModuleEntry*>* ModuleEntryTable::allocate_archived_entries() {
Array<ModuleEntry*>* archived_modules = ArchiveBuilder::new_rw_array<ModuleEntry*>(_table.number_of_entries()); int n = 0; auto grab = [&] (const SymbolHandle& key, ModuleEntry*& m) {
archived_modules->at_put(n++, m);
};
_table.iterate_all(grab);
if (n > 1) { // Always allocate in the same order to produce deterministic archive.
QuickSort::sort(archived_modules->data(), n, (_sort_Fn)compare_module_by_name, true);
} for (int i = 0; i < n; i++) {
archived_modules->at_put(i, archived_modules->at(i)->allocate_archived_entry());
ArchivePtrMarker::mark_pointer((address*)archived_modules->adr_at(i));
} return archived_modules;
}
void ModuleEntryTable::init_archived_entries(Array<ModuleEntry*>* archived_modules) {
assert(DumpSharedSpaces, "dump time only"); for (int i = 0; i < archived_modules->length(); i++) {
ModuleEntry* archived_entry = archived_modules->at(i);
archived_entry->init_as_archived_entry();
}
}
void ModuleEntryTable::init_archived_oops(Array<ModuleEntry*>* archived_modules) {
assert(DumpSharedSpaces, "dump time only"); for (int i = 0; i < archived_modules->length(); i++) {
ModuleEntry* archived_entry = archived_modules->at(i);
archived_entry->init_archived_oops();
}
}
for (int i = 0; i < archived_modules->length(); i++) {
ModuleEntry* archived_entry = archived_modules->at(i);
archived_entry->load_from_archive(loader_data);
_table.put(archived_entry->name(), archived_entry);
}
}
void ModuleEntryTable::restore_archived_oops(ClassLoaderData* loader_data, Array<ModuleEntry*>* archived_modules) {
assert(UseSharedSpaces, "runtime only"); for (int i = 0; i < archived_modules->length(); i++) {
ModuleEntry* archived_entry = archived_modules->at(i);
archived_entry->restore_archived_oops(loader_data);
}
} #endif// INCLUDE_CDS_JAVA_HEAP
// Create an entry in the class loader's module_entry_table. It is the // caller's responsibility to ensure that the entry has not already been // created.
ModuleEntry* ModuleEntryTable::locked_create_entry(Handle module_handle, bool is_open,
Symbol* module_name,
Symbol* module_version,
Symbol* module_location,
ClassLoaderData* loader_data) {
assert(module_name != NULL, "ModuleEntryTable locked_create_entry should never be called for unnamed module.");
assert(Module_lock->owned_by_self(), "should have the Module_lock");
assert(lookup_only(module_name) == NULL, "Module already exists");
ModuleEntry* entry = new ModuleEntry(module_handle, is_open, module_name,
module_version, module_location, loader_data); bool created = _table.put(module_name, entry);
assert(created, "should be"); return entry;
}
// lookup_only by Symbol* to find a ModuleEntry.
ModuleEntry* ModuleEntryTable::lookup_only(Symbol* name) {
assert_locked_or_safepoint(Module_lock);
assert(name != NULL, "name cannot be NULL");
ModuleEntry** entry = _table.get(name); return (entry == nullptr) ? nullptr : *entry;
}
// Remove dead modules from all other alive modules' reads list. // This should only occur at class unloading. void ModuleEntryTable::purge_all_module_reads() {
assert_locked_or_safepoint(Module_lock); auto purge = [&] (const SymbolHandle& key, ModuleEntry*& entry) {
entry->purge_reads();
};
_table.iterate_all(purge);
}
assert(module_table != NULL, "boot loader's ModuleEntryTable not defined");
if (module_handle.is_null()) {
fatal("Unable to finalize module definition for " JAVA_BASE_NAME);
}
// Set java.lang.Module, version and location for java.base
ModuleEntry* jb_module = javabase_moduleEntry();
assert(jb_module != NULL, JAVA_BASE_NAME " ModuleEntry not defined");
jb_module->set_version(version);
jb_module->set_location(location); // Once java.base's ModuleEntry _module field is set with the known // java.lang.Module, java.base is considered "defined" to the VM.
jb_module->set_module(boot_loader_data->add_handle(module_handle));
// Store pointer to the ModuleEntry for java.base in the java.lang.Module object.
java_lang_Module::set_module_entry(module_handle(), jb_module);
}
// Within java.lang.Class instances there is a java.lang.Module field that must // be set with the defining module. During startup, prior to java.base's definition, // classes needing their module field set are added to the fixup_module_list. // Their module field is set once java.base's java.lang.Module is known to the VM. void ModuleEntryTable::patch_javabase_entries(JavaThread* current, Handle module_handle) { if (module_handle.is_null()) {
fatal("Unable to patch the module field of classes loaded prior to "
JAVA_BASE_NAME "'s definition, invalid java.lang.Module");
}
// Do the fixups for the basic primitive types
java_lang_Class::set_module(Universe::int_mirror(), module_handle());
java_lang_Class::set_module(Universe::float_mirror(), module_handle());
java_lang_Class::set_module(Universe::double_mirror(), module_handle());
java_lang_Class::set_module(Universe::byte_mirror(), module_handle());
java_lang_Class::set_module(Universe::bool_mirror(), module_handle());
java_lang_Class::set_module(Universe::char_mirror(), module_handle());
java_lang_Class::set_module(Universe::long_mirror(), module_handle());
java_lang_Class::set_module(Universe::short_mirror(), module_handle());
java_lang_Class::set_module(Universe::void_mirror(), module_handle());
// Do the fixups for classes that have already been created.
GrowableArray <Klass*>* list = java_lang_Class::fixup_module_field_list(); int list_length = list->length(); for (int i = 0; i < list_length; i++) {
Klass* k = list->at(i);
assert(k->is_klass(), "List should only hold classes"); #ifndef PRODUCT if (HeapShared::is_a_test_class_in_unnamed_module(k)) { // We allow -XX:ArchiveHeapTestClass to archive additional classes // into the CDS heap, but these must be in the unnamed module.
ModuleEntry* unnamed_module = ClassLoaderData::the_null_class_loader_data()->unnamed_module();
Handle unnamed_module_handle(current, unnamed_module->module());
java_lang_Class::fixup_module_field(k, unnamed_module_handle);
} else #endif
{
java_lang_Class::fixup_module_field(k, module_handle);
}
k->class_loader_data()->dec_keep_alive();
}