Mon, 09 Jun 2008 11:51:19 -0400
6687581: Make CMS work with compressed oops
Summary: Make FreeChunk read markword instead of LSB in _klass pointer to indicate that it's a FreeChunk for compressed oops.
Reviewed-by: ysr, jmasa
1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
26 // the format of Java objects so the fields can be accessed from C++.
27 // oopDesc is abstract.
28 // (see oopHierarchy for complete oop class hierarchy)
29 //
30 // no virtual functions allowed
32 // store into oop with store check
33 template <class T> void oop_store(T* p, oop v);
34 template <class T> void oop_store(volatile T* p, oop v);
36 // store into oop without store check
37 template <class T> void oop_store_without_check(T* p, oop v);
38 template <class T> void oop_store_without_check(volatile T* p, oop v);
41 extern bool always_do_update_barrier;
43 // Forward declarations.
44 class OopClosure;
45 class ScanClosure;
46 class FastScanClosure;
47 class FilteringClosure;
48 class BarrierSet;
49 class CMSIsAliveClosure;
51 class PSPromotionManager;
52 class ParCompactionManager;
54 class oopDesc {
55 friend class VMStructs;
56 private:
57 volatile markOop _mark;
58 union _metadata {
59 wideKlassOop _klass;
60 narrowOop _compressed_klass;
61 } _metadata;
63 // Fast access to barrier set. Must be initialized.
64 static BarrierSet* _bs;
66 public:
67 markOop mark() const { return _mark; }
68 markOop* mark_addr() const { return (markOop*) &_mark; }
70 void set_mark(volatile markOop m) { _mark = m; }
72 void release_set_mark(markOop m);
73 markOop cas_set_mark(markOop new_mark, markOop old_mark);
75 // Used only to re-initialize the mark word (e.g., of promoted
76 // objects during a GC) -- requires a valid klass pointer
77 void init_mark();
79 klassOop klass() const;
80 klassOop klass_or_null() const volatile;
81 oop* klass_addr();
82 narrowOop* compressed_klass_addr();
84 void set_klass(klassOop k);
86 // For klass field compression
87 int klass_gap() const;
88 void set_klass_gap(int z);
89 // For when the klass pointer is being used as a linked list "next" field.
90 void set_klass_to_list_ptr(oop k);
92 // size of object header, aligned to platform wordSize
93 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
95 Klass* blueprint() const;
97 // Returns whether this is an instance of k or an instance of a subclass of k
98 bool is_a(klassOop k) const;
100 // Returns the actual oop size of the object
101 int size();
103 // Sometimes (for complicated concurrency-related reasons), it is useful
104 // to be able to figure out the size of an object knowing its klass.
105 int size_given_klass(Klass* klass);
107 // Some perm gen objects are not parseble immediately after
108 // installation of their klass pointer.
109 bool is_parsable();
111 // type test operations (inlined in oop.inline.h)
112 bool is_instance() const;
113 bool is_instanceRef() const;
114 bool is_array() const;
115 bool is_objArray() const;
116 bool is_symbol() const;
117 bool is_klass() const;
118 bool is_thread() const;
119 bool is_method() const;
120 bool is_constMethod() const;
121 bool is_methodData() const;
122 bool is_constantPool() const;
123 bool is_constantPoolCache() const;
124 bool is_typeArray() const;
125 bool is_javaArray() const;
126 bool is_compiledICHolder() const;
128 private:
129 // field addresses in oop
130 void* field_base(int offset) const;
132 jbyte* byte_field_addr(int offset) const;
133 jchar* char_field_addr(int offset) const;
134 jboolean* bool_field_addr(int offset) const;
135 jint* int_field_addr(int offset) const;
136 jshort* short_field_addr(int offset) const;
137 jlong* long_field_addr(int offset) const;
138 jfloat* float_field_addr(int offset) const;
139 jdouble* double_field_addr(int offset) const;
140 address* address_field_addr(int offset) const;
142 public:
143 // Need this as public for garbage collection.
144 template <class T> T* obj_field_addr(int offset) const;
146 // Oop encoding heap max
147 static const uint64_t OopEncodingHeapMax =
148 (uint64_t(max_juint) + 1) << LogMinObjAlignmentInBytes;
150 static bool is_null(oop obj);
151 static bool is_null(narrowOop obj);
153 // Decode an oop pointer from a narrowOop if compressed.
154 // These are overloaded for oop and narrowOop as are the other functions
155 // below so that they can be called in template functions.
156 static oop decode_heap_oop_not_null(oop v);
157 static oop decode_heap_oop_not_null(narrowOop v);
158 static oop decode_heap_oop(oop v);
159 static oop decode_heap_oop(narrowOop v);
161 // Encode an oop pointer to a narrow oop. The or_null versions accept
162 // null oop pointer, others do not in order to eliminate the
163 // null checking branches.
164 static narrowOop encode_heap_oop_not_null(oop v);
165 static narrowOop encode_heap_oop(oop v);
167 // Load an oop out of the Java heap
168 static narrowOop load_heap_oop(narrowOop* p);
169 static oop load_heap_oop(oop* p);
171 // Load an oop out of Java heap and decode it to an uncompressed oop.
172 static oop load_decode_heap_oop_not_null(narrowOop* p);
173 static oop load_decode_heap_oop_not_null(oop* p);
174 static oop load_decode_heap_oop(narrowOop* p);
175 static oop load_decode_heap_oop(oop* p);
177 // Store an oop into the heap.
178 static void store_heap_oop(narrowOop* p, narrowOop v);
179 static void store_heap_oop(oop* p, oop v);
181 // Encode oop if UseCompressedOops and store into the heap.
182 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
183 static void encode_store_heap_oop_not_null(oop* p, oop v);
184 static void encode_store_heap_oop(narrowOop* p, oop v);
185 static void encode_store_heap_oop(oop* p, oop v);
187 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
188 static void release_store_heap_oop(volatile oop* p, oop v);
190 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
191 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
192 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
193 static void release_encode_store_heap_oop(volatile oop* p, oop v);
195 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
196 static oop atomic_compare_exchange_oop(oop exchange_value,
197 volatile HeapWord *dest,
198 oop compare_value);
200 // Access to fields in a instanceOop through these methods.
201 oop obj_field(int offset) const;
202 void obj_field_put(int offset, oop value);
203 void obj_field_raw_put(int offset, oop value);
205 jbyte byte_field(int offset) const;
206 void byte_field_put(int offset, jbyte contents);
208 jchar char_field(int offset) const;
209 void char_field_put(int offset, jchar contents);
211 jboolean bool_field(int offset) const;
212 void bool_field_put(int offset, jboolean contents);
214 jint int_field(int offset) const;
215 void int_field_put(int offset, jint contents);
217 jshort short_field(int offset) const;
218 void short_field_put(int offset, jshort contents);
220 jlong long_field(int offset) const;
221 void long_field_put(int offset, jlong contents);
223 jfloat float_field(int offset) const;
224 void float_field_put(int offset, jfloat contents);
226 jdouble double_field(int offset) const;
227 void double_field_put(int offset, jdouble contents);
229 address address_field(int offset) const;
230 void address_field_put(int offset, address contents);
232 oop obj_field_acquire(int offset) const;
233 void release_obj_field_put(int offset, oop value);
235 jbyte byte_field_acquire(int offset) const;
236 void release_byte_field_put(int offset, jbyte contents);
238 jchar char_field_acquire(int offset) const;
239 void release_char_field_put(int offset, jchar contents);
241 jboolean bool_field_acquire(int offset) const;
242 void release_bool_field_put(int offset, jboolean contents);
244 jint int_field_acquire(int offset) const;
245 void release_int_field_put(int offset, jint contents);
247 jshort short_field_acquire(int offset) const;
248 void release_short_field_put(int offset, jshort contents);
250 jlong long_field_acquire(int offset) const;
251 void release_long_field_put(int offset, jlong contents);
253 jfloat float_field_acquire(int offset) const;
254 void release_float_field_put(int offset, jfloat contents);
256 jdouble double_field_acquire(int offset) const;
257 void release_double_field_put(int offset, jdouble contents);
259 // printing functions for VM debugging
260 void print_on(outputStream* st) const; // First level print
261 void print_value_on(outputStream* st) const; // Second level print.
262 void print_address_on(outputStream* st) const; // Address printing
264 // printing on default output stream
265 void print();
266 void print_value();
267 void print_address();
269 // return the print strings
270 char* print_string();
271 char* print_value_string();
273 // verification operations
274 void verify_on(outputStream* st);
275 void verify();
276 void verify_old_oop(oop* p, bool allow_dirty);
277 void verify_old_oop(narrowOop* p, bool allow_dirty);
279 // tells whether this oop is partially constructed (gc during class loading)
280 bool partially_loaded();
281 void set_partially_loaded();
283 // locking operations
284 bool is_locked() const;
285 bool is_unlocked() const;
286 bool has_bias_pattern() const;
288 // asserts
289 bool is_oop(bool ignore_mark_word = false) const;
290 bool is_oop_or_null(bool ignore_mark_word = false) const;
291 #ifndef PRODUCT
292 bool is_unlocked_oop() const;
293 #endif
295 // garbage collection
296 bool is_gc_marked() const;
297 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
298 // reference field in "this".
299 void follow_contents(void);
300 void follow_header(void);
302 #ifndef SERIALGC
303 // Parallel Scavenge
304 void copy_contents(PSPromotionManager* pm);
305 void push_contents(PSPromotionManager* pm);
307 // Parallel Old
308 void update_contents(ParCompactionManager* cm);
309 void update_contents(ParCompactionManager* cm,
310 HeapWord* begin_limit,
311 HeapWord* end_limit);
312 void update_contents(ParCompactionManager* cm,
313 klassOop old_klass,
314 HeapWord* begin_limit,
315 HeapWord* end_limit);
317 void follow_contents(ParCompactionManager* cm);
318 void follow_header(ParCompactionManager* cm);
319 #endif // SERIALGC
321 bool is_perm() const;
322 bool is_perm_or_null() const;
323 bool is_shared() const;
324 bool is_shared_readonly() const;
325 bool is_shared_readwrite() const;
327 // Forward pointer operations for scavenge
328 bool is_forwarded() const;
330 void forward_to(oop p);
331 bool cas_forward_to(oop p, markOop compare);
333 #ifndef SERIALGC
334 // Like "forward_to", but inserts the forwarding pointer atomically.
335 // Exactly one thread succeeds in inserting the forwarding pointer, and
336 // this call returns "NULL" for that thread; any other thread has the
337 // value of the forwarding pointer returned and does not modify "this".
338 oop forward_to_atomic(oop p);
339 #endif // SERIALGC
341 oop forwardee() const;
343 // Age of object during scavenge
344 int age() const;
345 void incr_age();
347 // Adjust all pointers in this object to point at it's forwarded location and
348 // return the size of this oop. This is used by the MarkSweep collector.
349 int adjust_pointers();
350 void adjust_header();
352 #ifndef SERIALGC
353 // Parallel old
354 void update_header();
355 void update_header(HeapWord* beg_addr, HeapWord* end_addr);
356 #endif // SERIALGC
358 // mark-sweep support
359 void follow_body(int begin, int end);
361 // Fast access to barrier set
362 static BarrierSet* bs() { return _bs; }
363 static void set_bs(BarrierSet* bs) { _bs = bs; }
365 // iterators, returns size of object
366 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
367 int oop_iterate(OopClosureType* blk); \
368 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
370 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
371 ALL_OOP_OOP_ITERATE_CLOSURES_3(OOP_ITERATE_DECL)
373 void oop_iterate_header(OopClosure* blk);
374 void oop_iterate_header(OopClosure* blk, MemRegion mr);
376 // identity hash; returns the identity hash key (computes it if necessary)
377 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
378 // safepoint if called on a biased object. Calling code must be aware of that.
379 intptr_t identity_hash();
380 intptr_t slow_identity_hash();
382 // marks are forwarded to stack when object is locked
383 bool has_displaced_mark() const;
384 markOop displaced_mark() const;
385 void set_displaced_mark(markOop m);
387 // for code generation
388 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
389 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
390 static int klass_gap_offset_in_bytes();
391 };