diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/classfile/moduleEntry.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/classfile/moduleEntry.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,510 @@
+/*
+ * Copyright (c) 2016, 2017, 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/classLoaderData.hpp"
+#include "classfile/javaClasses.hpp"
+#include "classfile/moduleEntry.hpp"
+#include "logging/log.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/symbol.hpp"
+#include "prims/jni.h"
+#include "runtime/handles.inline.hpp"
+#include "runtime/safepoint.hpp"
+#include "trace/traceMacros.hpp"
+#include "utilities/events.hpp"
+#include "utilities/growableArray.hpp"
+#include "utilities/hashtable.inline.hpp"
+#include "utilities/ostream.hpp"
+
+ModuleEntry* ModuleEntryTable::_javabase_module = NULL;
+
+void ModuleEntry::set_location(Symbol* location) {
+  if (_location != NULL) {
+    // _location symbol's refcounts are managed by ModuleEntry,
+    // must decrement the old one before updating.
+    _location->decrement_refcount();
+  }
+
+  _location = location;
+
+  if (location != NULL) {
+    location->increment_refcount();
+  }
+}
+
+bool ModuleEntry::is_non_jdk_module() {
+  ResourceMark rm;
+  if (location() != NULL) {
+    const char* loc = location()->as_C_string();
+    if (strncmp(loc, "jrt:/java.", 10) != 0 && strncmp(loc, "jrt:/jdk.", 9) != 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void ModuleEntry::set_version(Symbol* version) {
+  if (_version != NULL) {
+    // _version symbol's refcounts are managed by ModuleEntry,
+    // must decrement the old one before updating.
+    _version->decrement_refcount();
+  }
+
+  _version = version;
+
+  if (version != NULL) {
+    version->increment_refcount();
+  }
+}
+
+// Returns the shared ProtectionDomain
+oop ModuleEntry::shared_protection_domain() {
+  return _pd.resolve();
+}
+
+// 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 _pd cache.
+  loader_data->init_handle_locked(_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())) {
+    return true;
+  }
+
+  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();
+    if (cld->is_the_null_class_loader_data() || cld->is_system_class_loader_data()) {
+      return true; // default read edge
+    }
+  }
+  if (!has_reads_list()) {
+    return false;
+  } 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 (ResourceObj::C_HEAP, mtModule)GrowableArray<ModuleEntry*>(MODULE_READS_SIZE, true);
+    }
+
+    // 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(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+
+  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);
+      }
+    }
+  }
+}
+
+void ModuleEntry::module_reads_do(ModuleClosure* const f) {
+  assert_locked_or_safepoint(Module_lock);
+  assert(f != NULL, "invariant");
+
+  if (has_reads_list()) {
+    int reads_len = _reads->length();
+    for (int i = 0; i < reads_len; ++i) {
+      f->do_module(_reads->at(i));
+    }
+  }
+}
+
+void ModuleEntry::delete_reads() {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+  delete _reads;
+  _reads = NULL;
+}
+
+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());
+  ModuleEntry* unnamed_module = new_unnamed_module_entry(Handle(Thread::current(), module), cld);
+
+  // 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 = (ModuleEntry*) NEW_C_HEAP_ARRAY(char, sizeof(ModuleEntry), mtModule);
+
+  // Initialize everything BasicHashtable would
+  entry->set_next(NULL);
+  entry->set_hash(0);
+  entry->set_literal(NULL);
+
+  // Initialize fields specific to a ModuleEntry
+  entry->init();
+
+  // Unnamed modules can read all other unnamed modules.
+  entry->set_can_read_all_unnamed();
+
+  if (!module_handle.is_null()) {
+    entry->set_module(cld->add_handle(module_handle));
+  }
+
+  entry->set_loader_data(cld);
+  entry->_is_open = true;
+
+  TRACE_INIT_ID(entry);
+
+  return entry;
+}
+
+void ModuleEntry::delete_unnamed_module() {
+  // Do not need unlink_entry() since the unnamed module is not in the hashtable
+  FREE_C_HEAP_ARRAY(char, this);
+}
+
+ModuleEntryTable::ModuleEntryTable(int table_size)
+  : Hashtable<Symbol*, mtModule>(table_size, sizeof(ModuleEntry))
+{
+}
+
+ModuleEntryTable::~ModuleEntryTable() {
+  assert_locked_or_safepoint(Module_lock);
+
+  // Walk through all buckets and all entries in each bucket,
+  // freeing each entry.
+  for (int i = 0; i < table_size(); ++i) {
+    for (ModuleEntry* m = bucket(i); m != NULL;) {
+      ModuleEntry* to_remove = m;
+      // read next before freeing.
+      m = m->next();
+
+      ResourceMark rm;
+      if (to_remove->name() != NULL) {
+        log_info(module, unload)("unloading module %s", to_remove->name()->as_C_string());
+      }
+      log_debug(module)("ModuleEntryTable: deleting module: %s", to_remove->name() != NULL ?
+                        to_remove->name()->as_C_string() : UNNAMED_MODULE);
+
+      // Clean out the C heap allocated reads list first before freeing the entry
+      to_remove->delete_reads();
+      if (to_remove->name() != NULL) {
+        to_remove->name()->decrement_refcount();
+      }
+      if (to_remove->version() != NULL) {
+        to_remove->version()->decrement_refcount();
+      }
+      if (to_remove->location() != NULL) {
+        to_remove->location()->decrement_refcount();
+      }
+
+      // Unlink from the Hashtable prior to freeing
+      unlink_entry(to_remove);
+      FREE_C_HEAP_ARRAY(char, to_remove);
+    }
+  }
+  assert(number_of_entries() == 0, "should have removed all entries");
+  assert(new_entry_free_list() == NULL, "entry present on ModuleEntryTable's free list");
+  free_buckets();
+}
+
+ModuleEntry* ModuleEntryTable::new_entry(unsigned int hash, Handle module_handle,
+                                         bool is_open, Symbol* name,
+                                         Symbol* version, Symbol* location,
+                                         ClassLoaderData* loader_data) {
+  assert(Module_lock->owned_by_self(), "should have the Module_lock");
+  ModuleEntry* entry = (ModuleEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name);
+
+  // Initialize fields specific to a ModuleEntry
+  entry->init();
+  if (name != NULL) {
+    name->increment_refcount();
+  } else {
+    // Unnamed modules can read all other unnamed modules.
+    entry->set_can_read_all_unnamed();
+  }
+
+  if (!module_handle.is_null()) {
+    entry->set_module(loader_data->add_handle(module_handle));
+  }
+
+  entry->set_loader_data(loader_data);
+  entry->set_version(version);
+  entry->set_location(location);
+  entry->set_is_open(is_open);
+
+  if (ClassLoader::is_in_patch_mod_entries(name)) {
+    entry->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->as_C_string());
+    }
+  }
+
+  TRACE_INIT_ID(entry);
+
+  return entry;
+}
+
+void ModuleEntryTable::add_entry(int index, ModuleEntry* new_entry) {
+  assert(Module_lock->owned_by_self(), "should have the Module_lock");
+  Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
+}
+
+ModuleEntry* ModuleEntryTable::locked_create_entry_or_null(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_or_null should never be called for unnamed module.");
+  assert(Module_lock->owned_by_self(), "should have the Module_lock");
+  // Check if module already exists.
+  if (lookup_only(module_name) != NULL) {
+    return NULL;
+  } else {
+    ModuleEntry* entry = new_entry(compute_hash(module_name), module_handle, is_open, module_name,
+                                   module_version, module_location, loader_data);
+    add_entry(index_for(module_name), entry);
+    return entry;
+  }
+}
+
+// lookup_only by Symbol* to find a ModuleEntry.
+ModuleEntry* ModuleEntryTable::lookup_only(Symbol* name) {
+  assert(name != NULL, "name cannot be NULL");
+  int index = index_for(name);
+  for (ModuleEntry* m = bucket(index); m != NULL; m = m->next()) {
+    if (m->name()->fast_compare(name) == 0) {
+      return m;
+    }
+  }
+  return NULL;
+}
+
+// Remove dead modules from all other alive modules' reads list.
+// This should only occur at class unloading.
+void ModuleEntryTable::purge_all_module_reads() {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+  for (int i = 0; i < table_size(); i++) {
+    for (ModuleEntry* entry = bucket(i);
+                      entry != NULL;
+                      entry = entry->next()) {
+      entry->purge_reads();
+    }
+  }
+}
+
+void ModuleEntryTable::finalize_javabase(Handle module_handle, Symbol* version, Symbol* location) {
+  assert(Module_lock->owned_by_self(), "should have the Module_lock");
+  ClassLoaderData* boot_loader_data = ClassLoaderData::the_null_class_loader_data();
+  ModuleEntryTable* module_table = boot_loader_data->modules();
+
+  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(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");
+    java_lang_Class::fixup_module_field(k, module_handle);
+    k->class_loader_data()->dec_keep_alive();
+  }
+
+  delete java_lang_Class::fixup_module_field_list();
+  java_lang_Class::set_fixup_module_field_list(NULL);
+}
+
+void ModuleEntryTable::print(outputStream* st) {
+  st->print_cr("Module Entry Table (table_size=%d, entries=%d)",
+               table_size(), number_of_entries());
+  for (int i = 0; i < table_size(); i++) {
+    for (ModuleEntry* probe = bucket(i);
+                              probe != NULL;
+                              probe = probe->next()) {
+      probe->print(st);
+    }
+  }
+}
+
+void ModuleEntry::print(outputStream* st) {
+  ResourceMark rm;
+  st->print_cr("entry " PTR_FORMAT " name %s module " PTR_FORMAT " loader %s version %s location %s strict %s next " PTR_FORMAT,
+               p2i(this),
+               name() == NULL ? UNNAMED_MODULE : name()->as_C_string(),
+               p2i(module()),
+               loader_data()->loader_name(),
+               version() != NULL ? version()->as_C_string() : "NULL",
+               location() != NULL ? location()->as_C_string() : "NULL",
+               BOOL_TO_STR(!can_read_all_unnamed()), p2i(next()));
+}
+
+void ModuleEntryTable::verify() {
+  verify_table<ModuleEntry>("Module Entry Table");
+}
+
+void ModuleEntry::verify() {
+  guarantee(loader_data() != NULL, "A module entry must be associated with a loader.");
+}