1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_OOPS_OOP_HPP
26 #define SHARE_OOPS_OOP_HPP
27
28 #include "cppstdlib/type_traits.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "oops/accessDecorators.hpp"
32 #include "oops/compressedKlass.hpp"
33 #include "oops/markWord.hpp"
34 #include "oops/metadata.hpp"
35 #include "oops/objLayout.hpp"
36 #include "runtime/atomicAccess.hpp"
37 #include "utilities/globalDefinitions.hpp"
38 #include "utilities/macros.hpp"
39
40 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
41 // the format of Java objects so the fields can be accessed from C++.
42 // oopDesc is abstract.
43 // (see oopHierarchy for complete oop class hierarchy)
44 //
45 // no virtual functions allowed
46
47 class oopDesc {
48 friend class VMStructs;
49 friend class JVMCIVMStructs;
50 private:
51 volatile markWord _mark;
52 narrowKlass _compressed_klass;
53
54 // There may be ordering constraints on the initialization of fields that
55 // make use of the C++ copy/assign incorrect.
56 NONCOPYABLE(oopDesc);
57
58 inline oop cas_set_forwardee(markWord new_mark, markWord old_mark, atomic_memory_order order);
59
60 public:
61 // Must be trivial; see verifying static assert after the class.
62 oopDesc() = default;
63
64 inline void* base_addr();
65 inline const void* base_addr() const;
66
67 inline markWord mark() const;
68 inline markWord mark_acquire() const;
69
70 inline void set_mark(markWord m);
71 static inline void set_mark(HeapWord* mem, markWord m);
72 static inline void release_set_mark(HeapWord* mem, markWord m);
73
74 inline void release_set_mark(markWord m);
75 inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
76 inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
77
78 // Returns the prototype mark that should be used for this object.
79 inline markWord prototype_mark() const;
80
81 // Used only to re-initialize the mark word (e.g., of promoted
82 // objects during a GC) -- requires a valid klass pointer
83 inline void init_mark();
84
85 inline Klass* klass() const;
86 inline Klass* klass_or_null() const;
87 inline Klass* klass_or_null_acquire() const;
88 // Get the klass without running any asserts.
89 inline Klass* klass_without_asserts() const;
90
91 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
92 inline narrowKlass narrow_klass() const;
93 inline void set_klass(Klass* k);
94 static inline void release_set_klass(HeapWord* mem, Klass* k);
95
96 // For klass field compression
97 static inline void set_klass_gap(HeapWord* mem, int z);
98
99 // Size of object header, aligned to platform wordSize
100 static int header_size() {
101 if (UseCompactObjectHeaders) {
102 return sizeof(markWord) / HeapWordSize;
103 } else {
104 return sizeof(oopDesc) / HeapWordSize;
105 }
106 }
107
108 // Returns whether this is an instance of k or an instance of a subclass of k
109 inline bool is_a(Klass* k) const;
110
111 // Returns the actual oop size of the object in machine words
112 inline size_t size();
113
114 // Sometimes (for complicated concurrency-related reasons), it is useful
115 // to be able to figure out the size of an object knowing its klass.
116 inline size_t size_given_klass(Klass* klass);
117
118 // type test operations (inlined in oop.inline.hpp)
119 inline bool is_instance() const;
120 inline bool is_inline() const;
121 inline bool is_instanceRef() const;
122 inline bool is_stackChunk() const;
123 inline bool is_array() const;
124 inline bool is_objArray() const;
125 inline bool is_typeArray() const;
126 inline bool is_flatArray() const;
127 inline bool is_refArray() const;
128 inline bool is_refined_objArray() const;
129 inline bool is_array_with_oops() const;
130
131 inline bool is_inline_type() const;
132
133 // type test operations that don't require inclusion of oop.inline.hpp.
134 bool is_instance_noinline() const;
135 bool is_instanceRef_noinline() const;
136 bool is_stackChunk_noinline() const;
137 bool is_array_noinline() const;
138 bool is_objArray_noinline() const;
139 bool is_refArray_noinline() const;
140 bool is_typeArray_noinline() const;
141 bool is_flatArray_noinline() const;
142
143 protected:
144 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
145
146 public:
147 template<typename T>
148 inline T* field_addr(int offset) const;
149
150 template <typename T> inline size_t field_offset(T* p) const;
151
152 // Standard compare function returns negative value if o1 < o2
153 // 0 if o1 == o2
154 // positive value if o1 > o2
155 inline static int compare(oop o1, oop o2) {
156 void* o1_addr = (void*)o1;
157 void* o2_addr = (void*)o2;
158 if (o1_addr < o2_addr) {
159 return -1;
160 } else if (o1_addr > o2_addr) {
161 return 1;
162 } else {
163 return 0;
164 }
165 }
166
167 // Access to fields in a instanceOop through these methods.
168 template<DecoratorSet decorators>
169 oop obj_field_access(int offset) const;
170 oop obj_field(int offset) const;
171
172 void obj_field_put(int offset, oop value);
173 void obj_field_put_raw(int offset, oop value);
174 void obj_field_put_volatile(int offset, oop value);
175 template<DecoratorSet decorators>
176 void obj_field_put_access(int offset, oop value);
177
178 Metadata* metadata_field(int offset) const;
179 void metadata_field_put(int offset, Metadata* value);
180
181 Metadata* metadata_field_acquire(int offset) const;
182 void release_metadata_field_put(int offset, Metadata* value);
183
184 jbyte byte_field(int offset) const;
185 void byte_field_put(int offset, jbyte contents);
186
187 jchar char_field(int offset) const;
188 void char_field_put(int offset, jchar contents);
189
190 jboolean bool_field(int offset) const;
191 void bool_field_put(int offset, jboolean contents);
192 jboolean bool_field_volatile(int offset) const;
193 void bool_field_put_volatile(int offset, jboolean contents);
194
195 jint int_field(int offset) const;
196 void int_field_put(int offset, jint contents);
197
198 jshort short_field(int offset) const;
199 void short_field_put(int offset, jshort contents);
200
201 jlong long_field(int offset) const;
202 void long_field_put(int offset, jlong contents);
203
204 jfloat float_field(int offset) const;
205 void float_field_put(int offset, jfloat contents);
206
207 jdouble double_field(int offset) const;
208 void double_field_put(int offset, jdouble contents);
209
210 address address_field(int offset) const;
211 void address_field_put(int offset, address contents);
212
213 oop obj_field_acquire(int offset) const;
214 void release_obj_field_put(int offset, oop value);
215
216 jbyte byte_field_acquire(int offset) const;
217 void release_byte_field_put(int offset, jbyte contents);
218
219 jchar char_field_acquire(int offset) const;
220 void release_char_field_put(int offset, jchar contents);
221
222 jboolean bool_field_acquire(int offset) const;
223 void release_bool_field_put(int offset, jboolean contents);
224
225 jint int_field_relaxed(int offset) const;
226 void int_field_put_relaxed(int offset, jint contents);
227 jint int_field_acquire(int offset) const;
228 void release_int_field_put(int offset, jint contents);
229
230 jshort short_field_acquire(int offset) const;
231 void release_short_field_put(int offset, jshort contents);
232
233 jlong long_field_acquire(int offset) const;
234 void release_long_field_put(int offset, jlong contents);
235
236 jfloat float_field_acquire(int offset) const;
237 void release_float_field_put(int offset, jfloat contents);
238
239 jdouble double_field_acquire(int offset) const;
240 void release_double_field_put(int offset, jdouble contents);
241
242 address address_field_acquire(int offset) const;
243 void release_address_field_put(int offset, address contents);
244
245 // printing functions for VM debugging
246 void print_on(outputStream* st) const; // First level print
247 void print_value_on(outputStream* st) const; // Second level print.
248 void print_address_on(outputStream* st) const; // Address printing
249 void print_name_on(outputStream* st) const; // External name printing.
250
251 // printing on default output stream
252 void print();
253 void print_value();
254 void print_address();
255
256 // return the print strings
257 char* print_string();
258 char* print_value_string();
259
260 // verification operations
261 static void verify_on(outputStream* st, oopDesc* oop_desc);
262 static void verify(oopDesc* oopDesc);
263
264 // locking operations
265 inline bool is_locked() const;
266 inline bool is_unlocked() const;
267
268 // asserts and guarantees
269 static bool is_oop(oop obj);
270 static bool is_oop_or_null(oop obj);
271
272 // garbage collection
273 inline bool is_gc_marked() const;
274
275 // Forward pointer operations for scavenge
276 inline bool is_forwarded() const;
277 inline bool is_self_forwarded() const;
278
279 inline void forward_to(oop p);
280 inline void forward_to_self();
281
282 // Like "forward_to", but inserts the forwarding pointer atomically.
283 // Exactly one thread succeeds in inserting the forwarding pointer, and
284 // this call returns null for that thread; any other thread has the
285 // value of the forwarding pointer returned and does not modify "this".
286 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
287 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
288
289 inline oop forwardee() const;
290 inline oop forwardee(markWord header) const;
291
292 inline void unset_self_forwarded();
293
294 // Age of object during scavenge
295 inline uint age() const;
296 inline void incr_age();
297
298 template <typename OopClosureType>
299 inline void oop_iterate(OopClosureType* cl);
300
301 template <typename OopClosureType>
302 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
303
304 template <typename OopClosureType>
305 inline size_t oop_iterate_size(OopClosureType* cl);
306
307 template <typename OopClosureType>
308 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
309
310 template <typename OopClosureType>
311 inline void oop_iterate_backwards(OopClosureType* cl);
312
313 template <typename OopClosureType>
314 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
315
316 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
317
318 // identity hash; returns the identity hash key (computes it if necessary)
319 inline intptr_t identity_hash();
320 intptr_t slow_identity_hash();
321 inline bool fast_no_hash_check();
322
323 // marks are forwarded to stack when object is locked
324 inline bool has_displaced_mark() const;
325 inline markWord displaced_mark() const;
326 inline void set_displaced_mark(markWord m);
327
328 // Checks if the mark word needs to be preserved
329 inline bool mark_must_be_preserved() const;
330 inline bool mark_must_be_preserved(markWord m) const;
331
332 inline static bool has_klass_gap() {
333 return ObjLayout::oop_has_klass_gap();
334 }
335
336 // for code generation
337 static int mark_offset_in_bytes() { return (int)offset_of(oopDesc, _mark); }
338 static int klass_offset_in_bytes() {
339 #ifdef _LP64
340 if (UseCompactObjectHeaders) {
341 // NOTE: The only places where this is used with compact headers are the C2
342 // compiler and JVMCI.
343 return mark_offset_in_bytes() + markWord::klass_offset_in_bytes;
344 } else
345 #endif
346 {
347 return (int)offset_of(oopDesc, _compressed_klass);
348 }
349 }
350 static int klass_gap_offset_in_bytes() {
351 assert(has_klass_gap(), "only applicable to compressed klass pointers");
352 return klass_offset_in_bytes() + sizeof(narrowKlass);
353 }
354
355 static int base_offset_in_bytes() {
356 return ObjLayout::oop_base_offset_in_bytes();
357 }
358
359 // for error reporting
360 static void* load_oop_raw(oop obj, int offset);
361 };
362
363 // An oopDesc is not initialized via a constructor. Space is allocated in
364 // the Java heap, and static functions provided here on HeapWord* are used
365 // to fill in certain parts of that memory. The allocated memory is then
366 // treated as referring to an oopDesc. For that to be valid, the oopDesc
367 // class must have a trivial default constructor (C++14 3.8/1).
368 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
369
370 #endif // SHARE_OOPS_OOP_HPP