1 /*
2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/moduleEntry.hpp"
27 #include "classfile/packageEntry.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/symbol.hpp"
30 #include "runtime/handles.inline.hpp"
31 #include "trace/traceMacros.hpp"
32 #include "utilities/events.hpp"
33 #include "utilities/growableArray.hpp"
34 #include "utilities/hashtable.inline.hpp"
35 #include "utilities/ostream.hpp"
36
37 // Returns true if this package specifies m as a qualified export, including through an unnamed export
38 bool PackageEntry::is_qexported_to(ModuleEntry* m) const {
39 assert(m != NULL, "No module to lookup in this package's qualified exports list");
40 MutexLocker m1(Module_lock);
41 if (is_exported_allUnnamed() && !m->is_named()) {
42 return true;
43 } else if (!has_qual_exports_list()) {
44 return false;
45 } else {
46 return _qualified_exports->contains(m);
47 }
48 }
49
50 // Add a module to the package's qualified export list.
51 void PackageEntry::add_qexport(ModuleEntry* m) {
52 assert(Module_lock->owned_by_self(), "should have the Module_lock");
53 if (!has_qual_exports_list()) {
54 // Lazily create a package's qualified exports list.
55 // Initial size is small, do not anticipate export lists to be large.
56 _qualified_exports =
57 new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true);
58 }
59 _qualified_exports->append_if_missing(m);
60 }
61
62 // Set the package's exported states based on the value of the ModuleEntry.
63 void PackageEntry::set_exported(ModuleEntry* m) {
64 MutexLocker m1(Module_lock);
65 if (is_unqual_exported()) {
66 // An exception could be thrown, but choose to simply ignore.
67 // Illegal to convert an unqualified exported package to be qualifiedly exported
68 return;
69 }
70
71 if (m == NULL) {
72 // NULL indicates the package is being unqualifiedly exported
73 if (has_qual_exports_list()) {
74 // Legit to transition a package from being qualifiedly exported
75 // to unqualified. Clean up the qualified lists at the next
76 // safepoint.
77 _exported_pending_delete = _qualified_exports;
78 }
79
80 // Mark package as unqualifiedly exported
81 set_unqual_exported();
82
83 } else {
84 // Add the exported module
85 add_qexport(m);
86 }
87 }
88
89 void PackageEntry::set_is_exported_allUnnamed() {
90 MutexLocker m1(Module_lock);
91 if (!is_unqual_exported()) {
92 _is_exported_allUnnamed = true;
93 }
94 }
95
96 // Remove dead module entries within the package's exported list.
97 void PackageEntry::purge_qualified_exports() {
98 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
99 if (_qualified_exports != NULL) {
100 // Go backwards because this removes entries that are dead.
101 int len = _qualified_exports->length();
102 for (int idx = len - 1; idx >= 0; idx--) {
103 ModuleEntry* module_idx = _qualified_exports->at(idx);
104 ClassLoaderData* cld = module_idx->loader();
105 if (cld->is_unloading()) {
106 _qualified_exports->delete_at(idx);
107 }
108 }
109 }
110 }
111
112 void PackageEntry::delete_qualified_exports() {
113 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
114 if (_exported_pending_delete != NULL) {
115 // If a transition occurred from qualified to unqualified, the _qualified_exports
116 // field should have been NULL'ed out.
117 assert(_qualified_exports == NULL, "Package's exported pending delete, exported list should not be active");
118 delete _exported_pending_delete;
119 }
120
121 if (_qualified_exports != NULL) {
122 delete _qualified_exports;
123 }
124
125 _exported_pending_delete = NULL;
126 _qualified_exports = NULL;
127 }
128
129 PackageEntryTable::PackageEntryTable(int table_size)
130 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry))
131 {
132 }
133
134 PackageEntryTable::~PackageEntryTable() {
135 assert_locked_or_safepoint(Module_lock);
136
137 // Walk through all buckets and all entries in each bucket,
138 // freeing each entry.
139 for (int i = 0; i < table_size(); ++i) {
140 for (PackageEntry* p = bucket(i); p != NULL;) {
141 PackageEntry* to_remove = p;
142 // read next before freeing.
143 p = p->next();
144
145 // Clean out the C heap allocated qualified exports list first before freeing the entry
146 to_remove->delete_qualified_exports();
147 to_remove->name()->decrement_refcount();
148
149 // Unlink from the Hashtable prior to freeing
150 unlink_entry(to_remove);
151 FREE_C_HEAP_ARRAY(char, to_remove);
152 }
153 }
154 assert(number_of_entries() == 0, "should have removed all entries");
155 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list");
156 free_buckets();
157 }
158
159 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
160 assert(Module_lock->owned_by_self(), "should have the Module_lock");
161 PackageEntry* entry = (PackageEntry*) NEW_C_HEAP_ARRAY(char, entry_size(), mtModule);
162
163 // Initialize everything BasicHashtable would
164 entry->set_next(NULL);
165 entry->set_hash(hash);
166 entry->set_literal(name);
167
168 TRACE_INIT_PACKAGE_ID(entry);
169
170 // Initialize fields specific to a PackageEntry
171 entry->init();
172 entry->name()->increment_refcount();
173 if (!module->is_named()) {
174 // Set the exported state to true because all packages
175 // within the unnamed module are unqualifiedly exported
176 entry->set_unqual_exported();
177 }
178 entry->set_module(module);
179 return entry;
180 }
181
182 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
183 assert(Module_lock->owned_by_self(), "should have the Module_lock");
184 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
185 }
186
187 // Create package in loader's package entry table and return the entry.
188 // If entry already exists, return null. Assume Module lock was taken by caller.
189 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) {
190 assert(Module_lock->owned_by_self(), "should have the Module_lock");
191 // Check if package already exists. Return NULL if it does.
192 if (lookup_only(name) != NULL) {
193 return NULL;
194 } else {
195 PackageEntry* entry = new_entry(compute_hash(name), name, module);
196 add_entry(index_for(name), entry);
197 return entry;
198 }
199 }
200
201 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
202 PackageEntry* p = lookup_only(name);
203 if (p != NULL) {
204 return p;
205 } else {
206 // If not found, add to table. Grab the PackageEntryTable lock first.
207 MutexLocker ml(Module_lock);
208
209 // Since look-up was done lock-free, we need to check if another thread beat
210 // us in the race to insert the package.
211 PackageEntry* test = lookup_only(name);
212 if (test != NULL) {
213 // A race occurred and another thread introduced the package.
214 return test;
215 } else {
216 assert(module != NULL, "module should never be null");
217 PackageEntry* entry = new_entry(compute_hash(name), name, module);
218 add_entry(index_for(name), entry);
219 return entry;
220 }
221 }
222 }
223
224 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
225 int index = index_for(name);
226 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
227 if (p->name()->fast_compare(name) == 0) {
228 return p;
229 }
230 }
231 return NULL;
232 }
233
234 // Called when a define module for java.base is being processed.
235 // Verify the packages loaded thus far are in java.base's package list.
236 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
237 for (int i = 0; i < table_size(); i++) {
238 for (PackageEntry* entry = bucket(i);
239 entry != NULL;
240 entry = entry->next()) {
241 ModuleEntry* m = entry->module();
242 Symbol* module_name = (m == NULL ? NULL : m->name());
243 if (module_name != NULL &&
244 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
245 !pkg_list->contains(entry->name())) {
246 ResourceMark rm;
247 vm_exit_during_initialization("A non-java.base package was loaded prior to module system initialization", entry->name()->as_C_string());
248 }
249 }
250 }
251
252 }
253
254 // iteration of qualified exports
255 void PackageEntry::package_exports_do(ModuleClosure* const f) {
256 assert_locked_or_safepoint(Module_lock);
257 assert(f != NULL, "invariant");
258
259 if (has_qual_exports_list()) {
260 int qe_len = _qualified_exports->length();
261
262 for (int i = 0; i < qe_len; ++i) {
263 f->do_module(_qualified_exports->at(i));
264 }
265 }
266 }
267
268 // Remove dead entries from all packages' exported list
269 void PackageEntryTable::purge_all_package_exports() {
270 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
271 for (int i = 0; i < table_size(); i++) {
272 for (PackageEntry* entry = bucket(i);
273 entry != NULL;
274 entry = entry->next()) {
275 if (entry->exported_pending_delete()) {
276 // exported list is pending deletion due to a transition
277 // from qualified to unqualified
278 entry->delete_qualified_exports();
279 } else if (entry->is_qual_exported()) {
280 entry->purge_qualified_exports();
281 }
282 }
283 }
284 }
285
286 void PackageEntryTable::print(outputStream* st) {
287 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
288 table_size(), number_of_entries());
289 for (int i = 0; i < table_size(); i++) {
290 for (PackageEntry* probe = bucket(i);
291 probe != NULL;
292 probe = probe->next()) {
293 probe->print(st);
294 }
295 }
296 }
297
298 void PackageEntry::print(outputStream* st) {
299 ResourceMark rm;
300 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
301 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
302 p2i(this), name()->as_C_string(),
303 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
304 _classpath_index, _is_exported_unqualified, _is_exported_allUnnamed, p2i(next()));
305 }
306
307 void PackageEntryTable::verify() {
308 int element_count = 0;
309 for (int index = 0; index < table_size(); index++) {
310 for (PackageEntry* probe = bucket(index);
311 probe != NULL;
312 probe = probe->next()) {
313 probe->verify();
314 element_count++;
315 }
316 }
317 guarantee(number_of_entries() == element_count,
318 "Verify of Package Entry Table failed");
319 debug_only(verify_lookup_length((double)number_of_entries() / table_size()));
320 }
321
322 void PackageEntry::verify() {
323 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
324 }