Thu, 22 May 2014 15:52:41 -0400
8037816: Fix for 8036122 breaks build with Xcode5/clang
8043029: Change 8037816 breaks HS build with older GCC versions which don't support diagnostic pragmas
8043164: Format warning in traceStream.hpp
Summary: Backport of main fix + two corrections, enables clang compilation, turns on format attributes, corrects/mutes warnings
Reviewed-by: kvn, coleenp, iveresov, twisti
1 /*
2 * Copyright (c) 2012, 2014, 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 */
25 #ifndef SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP
26 #define SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP
28 #include "memory/allocation.hpp"
29 #include "memory/memRegion.hpp"
30 #include "memory/metaspace.hpp"
31 #include "memory/metaspaceCounters.hpp"
32 #include "runtime/mutex.hpp"
33 #include "utilities/growableArray.hpp"
35 #if INCLUDE_TRACE
36 # include "utilities/ticks.hpp"
37 #endif
39 //
40 // A class loader represents a linkset. Conceptually, a linkset identifies
41 // the complete transitive closure of resolved links that a dynamic linker can
42 // produce.
43 //
44 // A ClassLoaderData also encapsulates the allocation space, called a metaspace,
45 // used by the dynamic linker to allocate the runtime representation of all
46 // the types it defines.
47 //
48 // ClassLoaderData are stored in the runtime representation of classes and the
49 // system dictionary, are roots of garbage collection, and provides iterators
50 // for root tracing and other GC operations.
52 class ClassLoaderData;
53 class JNIMethodBlock;
54 class JNIHandleBlock;
55 class Metadebug;
57 // GC root for walking class loader data created
59 class ClassLoaderDataGraph : public AllStatic {
60 friend class ClassLoaderData;
61 friend class ClassLoaderDataGraphMetaspaceIterator;
62 friend class VMStructs;
63 private:
64 // All CLDs (except the null CLD) can be reached by walking _head->_next->...
65 static ClassLoaderData* _head;
66 static ClassLoaderData* _unloading;
67 // CMS support.
68 static ClassLoaderData* _saved_head;
69 static bool _should_purge;
71 static ClassLoaderData* add(Handle class_loader, bool anonymous, TRAPS);
72 static void post_class_unload_events(void);
73 public:
74 static ClassLoaderData* find_or_create(Handle class_loader, TRAPS);
75 static void purge();
76 static void clear_claimed_marks();
77 static void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
78 static void always_strong_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
79 static void keep_alive_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
80 static void classes_do(KlassClosure* klass_closure);
81 static void classes_do(void f(Klass* const));
82 static void loaded_classes_do(KlassClosure* klass_closure);
83 static void classes_unloading_do(void f(Klass* const));
84 static bool do_unloading(BoolObjectClosure* is_alive);
86 // CMS support.
87 static void remember_new_clds(bool remember) { _saved_head = (remember ? _head : NULL); }
88 static GrowableArray<ClassLoaderData*>* new_clds();
90 static void set_should_purge(bool b) { _should_purge = b; }
91 static void purge_if_needed() {
92 // Only purge the CLDG for CMS if concurrent sweep is complete.
93 if (_should_purge) {
94 purge();
95 // reset for next time.
96 set_should_purge(false);
97 }
98 }
100 static void dump_on(outputStream * const out) PRODUCT_RETURN;
101 static void dump() { dump_on(tty); }
102 static void verify();
104 #ifndef PRODUCT
105 static bool contains_loader_data(ClassLoaderData* loader_data);
106 #endif
108 #if INCLUDE_TRACE
109 private:
110 static Ticks _class_unload_time;
111 static void class_unload_event(Klass* const k);
112 #endif
113 };
115 // ClassLoaderData class
117 class ClassLoaderData : public CHeapObj<mtClass> {
118 friend class VMStructs;
119 private:
120 class Dependencies VALUE_OBJ_CLASS_SPEC {
121 objArrayOop _list_head;
122 void locked_add(objArrayHandle last,
123 objArrayHandle new_dependency,
124 Thread* THREAD);
125 public:
126 Dependencies() : _list_head(NULL) {}
127 Dependencies(TRAPS) : _list_head(NULL) {
128 init(CHECK);
129 }
130 void add(Handle dependency, TRAPS);
131 void init(TRAPS);
132 void oops_do(OopClosure* f);
133 };
135 friend class ClassLoaderDataGraph;
136 friend class ClassLoaderDataGraphMetaspaceIterator;
137 friend class MetaDataFactory;
138 friend class Method;
140 static ClassLoaderData * _the_null_class_loader_data;
142 oop _class_loader; // oop used to uniquely identify a class loader
143 // class loader or a canonical class path
144 Dependencies _dependencies; // holds dependencies from this class loader
145 // data to others.
147 Metaspace * _metaspace; // Meta-space where meta-data defined by the
148 // classes in the class loader are allocated.
149 Mutex* _metaspace_lock; // Locks the metaspace for allocations and setup.
150 bool _unloading; // true if this class loader goes away
151 bool _keep_alive; // if this CLD can be unloaded for anonymous loaders
152 bool _is_anonymous; // if this CLD is for an anonymous class
153 volatile int _claimed; // true if claimed, for example during GC traces.
154 // To avoid applying oop closure more than once.
155 // Has to be an int because we cas it.
156 Klass* _klasses; // The classes defined by the class loader.
158 JNIHandleBlock* _handles; // Handles to constant pool arrays
160 // These method IDs are created for the class loader and set to NULL when the
161 // class loader is unloaded. They are rarely freed, only for redefine classes
162 // and if they lose a data race in InstanceKlass.
163 JNIMethodBlock* _jmethod_ids;
165 // Metadata to be deallocated when it's safe at class unloading, when
166 // this class loader isn't unloaded itself.
167 GrowableArray<Metadata*>* _deallocate_list;
169 // Support for walking class loader data objects
170 ClassLoaderData* _next; /// Next loader_datas created
172 // ReadOnly and ReadWrite metaspaces (static because only on the null
173 // class loader for now).
174 static Metaspace* _ro_metaspace;
175 static Metaspace* _rw_metaspace;
177 void set_next(ClassLoaderData* next) { _next = next; }
178 ClassLoaderData* next() const { return _next; }
180 ClassLoaderData(Handle h_class_loader, bool is_anonymous, Dependencies dependencies);
181 ~ClassLoaderData();
183 void set_metaspace(Metaspace* m) { _metaspace = m; }
185 JNIHandleBlock* handles() const;
186 void set_handles(JNIHandleBlock* handles);
188 Mutex* metaspace_lock() const { return _metaspace_lock; }
190 // GC interface.
191 void clear_claimed() { _claimed = 0; }
192 bool claimed() const { return _claimed == 1; }
193 bool claim();
195 void unload();
196 bool keep_alive() const { return _keep_alive; }
197 bool is_alive(BoolObjectClosure* is_alive_closure) const;
198 void classes_do(void f(Klass*));
199 void loaded_classes_do(KlassClosure* klass_closure);
200 void classes_do(void f(InstanceKlass*));
202 // Deallocate free list during class unloading.
203 void free_deallocate_list();
205 // Allocate out of this class loader data
206 MetaWord* allocate(size_t size);
208 public:
209 // Accessors
210 Metaspace* metaspace_or_null() const { return _metaspace; }
212 static ClassLoaderData* the_null_class_loader_data() {
213 return _the_null_class_loader_data;
214 }
216 bool is_anonymous() const { return _is_anonymous; }
218 static void init_null_class_loader_data() {
219 assert(_the_null_class_loader_data == NULL, "cannot initialize twice");
220 assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice");
222 // We explicitly initialize the Dependencies object at a later phase in the initialization
223 _the_null_class_loader_data = new ClassLoaderData((oop)NULL, false, Dependencies());
224 ClassLoaderDataGraph::_head = _the_null_class_loader_data;
225 assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be");
226 if (DumpSharedSpaces) {
227 _the_null_class_loader_data->initialize_shared_metaspaces();
228 }
229 }
231 bool is_the_null_class_loader_data() const {
232 return this == _the_null_class_loader_data;
233 }
234 bool is_ext_class_loader_data() const;
236 // The Metaspace is created lazily so may be NULL. This
237 // method will allocate a Metaspace if needed.
238 Metaspace* metaspace_non_null();
240 oop class_loader() const { return _class_loader; }
242 // Returns true if this class loader data is for a loader going away.
243 bool is_unloading() const {
244 assert(!(is_the_null_class_loader_data() && _unloading), "The null class loader can never be unloaded");
245 return _unloading;
246 }
247 // Anonymous class loader data doesn't have anything to keep them from
248 // being unloaded during parsing the anonymous class.
249 void set_keep_alive(bool value) { _keep_alive = value; }
251 unsigned int identity_hash() {
252 return _class_loader == NULL ? 0 : _class_loader->identity_hash();
253 }
255 // Used when tracing from klasses.
256 void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
258 void classes_do(KlassClosure* klass_closure);
260 JNIMethodBlock* jmethod_ids() const { return _jmethod_ids; }
261 void set_jmethod_ids(JNIMethodBlock* new_block) { _jmethod_ids = new_block; }
263 void print_value() { print_value_on(tty); }
264 void print_value_on(outputStream* out) const;
265 void dump(outputStream * const out) PRODUCT_RETURN;
266 void verify();
267 const char* loader_name();
269 jobject add_handle(Handle h);
270 void add_class(Klass* k);
271 void remove_class(Klass* k);
272 bool contains_klass(Klass* k);
273 void record_dependency(Klass* to, TRAPS);
274 void init_dependencies(TRAPS);
276 void add_to_deallocate_list(Metadata* m);
278 static ClassLoaderData* class_loader_data(oop loader);
279 static ClassLoaderData* class_loader_data_or_null(oop loader);
280 static ClassLoaderData* anonymous_class_loader_data(oop loader, TRAPS);
281 static void print_loader(ClassLoaderData *loader_data, outputStream *out);
283 // CDS support
284 Metaspace* ro_metaspace();
285 Metaspace* rw_metaspace();
286 void initialize_shared_metaspaces();
287 };
289 class ClassLoaderDataGraphMetaspaceIterator : public StackObj {
290 ClassLoaderData* _data;
291 public:
292 ClassLoaderDataGraphMetaspaceIterator();
293 ~ClassLoaderDataGraphMetaspaceIterator();
294 bool repeat() { return _data != NULL; }
295 Metaspace* get_next() {
296 assert(_data != NULL, "Should not be NULL in call to the iterator");
297 Metaspace* result = _data->metaspace_or_null();
298 _data = _data->next();
299 // This result might be NULL for class loaders without metaspace
300 // yet. It would be nice to return only non-null results but
301 // there is no guarantee that there will be a non-null result
302 // down the list so the caller is going to have to check.
303 return result;
304 }
305 };
306 #endif // SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP