1 /*
2 * Copyright (c) 1997, 2020, 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
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23 */
24
25 #ifndef SHARE_MEMORY_UNIVERSE_HPP
26 #define SHARE_MEMORY_UNIVERSE_HPP
27
28 #include "gc/shared/verifyOption.hpp"
29 #include "oops/array.hpp"
30 #include "oops/oopHandle.hpp"
31 #include "runtime/handles.hpp"
32 #include "utilities/growableArray.hpp"
33
34 // Universe is a name space holding known system classes and objects in the VM.
35 //
36 // Loaded classes are accessible through the SystemDictionary.
37 //
38 // The object heap is allocated and accessed through Universe, and various allocation
39 // support is provided. Allocation by the interpreter and compiled code is done inline
40 // and bails out to Scavenge::invoke_and_allocate.
41
42 class CollectedHeap;
43 class DeferredObjAllocEvent;
44 class OopStorage;
45
46 // A helper class for caching a Method* when the user of the cache
47 // only cares about the latest version of the Method*. This cache safely
48 // interacts with the RedefineClasses API.
49
50 class LatestMethodCache : public CHeapObj<mtClass> {
51 // We save the Klass* and the idnum of Method* in order to get
52 // the current cached Method*.
53 private:
54 Klass* _klass;
55 int _method_idnum;
56
57 public:
58 LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
59 ~LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
60
61 void init(Klass* k, Method* m);
62 Klass* klass() const { return _klass; }
63 int method_idnum() const { return _method_idnum; }
64
65 Method* get_method();
66
67 // CDS support. Replace the klass in this with the archive version
68 // could use this for Enhanced Class Redefinition also.
69 void serialize(SerializeClosure* f) {
70 f->do_ptr((void**)&_klass);
71 }
72 void metaspace_pointers_do(MetaspaceClosure* it);
73 };
74
75 class Universe: AllStatic {
76 // Ugh. Universe is much too friendly.
77 friend class MarkSweep;
78 friend class oopDesc;
79 friend class ClassLoader;
80 friend class SystemDictionary;
81 friend class ReservedHeapSpace;
82 friend class VMStructs;
83 friend class VM_PopulateDumpSharedSpace;
84 friend class Metaspace;
85 friend class MetaspaceShared;
86
87 friend jint universe_init();
88 friend void universe2_init();
89 friend bool universe_post_init();
90 friend void universe_post_module_init();
91
92 private:
93 // Known classes in the VM
94 static Klass* _typeArrayKlassObjs[T_LONG+1];
95 static Klass* _objectArrayKlassObj;
96
97 // Known objects in the VM
98 static OopHandle _main_thread_group; // Reference to the main thread group object
99 static OopHandle _system_thread_group; // Reference to the system thread group object
100
101 static OopHandle _the_empty_class_array; // Canonicalized obj array of type java.lang.Class
102 static OopHandle _the_null_string; // A cache of "null" as a Java string
103 static OopHandle _the_min_jint_string; // A cache of "-2147483648" as a Java string
104
105 static OopHandle _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
106
107 // preallocated error objects (no backtrace)
108 static OopHandle _out_of_memory_errors;
109
110 // preallocated cause message for delayed StackOverflowError
111 static OopHandle _delayed_stack_overflow_error_message;
112
113 static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects
114 static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector
115 static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method
116 static LatestMethodCache* _throw_no_such_method_error_cache; // Unsafe.throwNoSuchMethodError() method
117 static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback
118
119 static Array<int>* _the_empty_int_array; // Canonicalized int array
120 static Array<u2>* _the_empty_short_array; // Canonicalized short array
121 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
122 static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
123 static Array<Method*>* _the_empty_method_array; // Canonicalized method array
124
125 static Array<Klass*>* _the_array_interfaces_array;
126
127 // array of preallocated error objects with backtrace
128 static OopHandle _preallocated_out_of_memory_error_array;
129
130 // number of preallocated error objects available for use
131 static volatile jint _preallocated_out_of_memory_error_avail_count;
132
133 static OopHandle _null_ptr_exception_instance; // preallocated exception object
134 static OopHandle _arithmetic_exception_instance; // preallocated exception object
135 static OopHandle _virtual_machine_error_instance; // preallocated exception object
136
137 // References waiting to be transferred to the ReferenceHandler
138 static oop _reference_pending_list;
139
140 // The particular choice of collected heap.
141 static CollectedHeap* _collectedHeap;
142
143 static intptr_t _non_oop_bits;
144
145 // array of dummy objects used with +FullGCAlot
146 debug_only(static OopHandle _fullgc_alot_dummy_array;)
147 debug_only(static int _fullgc_alot_dummy_next;)
148
149 // Compiler/dispatch support
150 static int _base_vtable_size; // Java vtbl size of klass Object (in words)
151
152 // Initialization
153 static bool _bootstrapping; // true during genesis
154 static bool _module_initialized; // true after call_initPhase2 called
155 static bool _fully_initialized; // true after universe_init and initialize_vtables called
156
157 // the array of preallocated errors with backtraces
158 static objArrayOop preallocated_out_of_memory_errors();
159
160 static objArrayOop out_of_memory_errors();
161 // generate an out of memory error; if possible using an error with preallocated backtrace;
162 // otherwise return the given default error.
163 static oop gen_out_of_memory_error(oop default_err);
164
165 // Historic gc information
166 static size_t _heap_capacity_at_last_gc;
167 static size_t _heap_used_at_last_gc;
168
169 static OopStorage* _vm_weak;
170 static OopStorage* _vm_global;
171
172 static jint initialize_heap();
173 static void initialize_tlab();
174 static void initialize_basic_type_mirrors(TRAPS);
175 static void fixup_mirrors(TRAPS);
176
177 static void reinitialize_vtable_of(Klass* k, TRAPS);
178 static void reinitialize_vtables(TRAPS);
179 static void reinitialize_itables(TRAPS);
180 static void compute_base_vtable_size(); // compute vtable size of class Object
181
182 static void genesis(TRAPS); // Create the initial world
183
184 // Mirrors for primitive classes (created eagerly)
185 static oop check_mirror(oop m) {
186 assert(m != NULL, "mirror not initialized");
187 return m;
188 }
189
190 // Debugging
191 static int _verify_count; // number of verifies done
192
193 // True during call to verify(). Should only be set/cleared in verify().
194 static bool _verify_in_progress;
195 static long verify_flags;
196
197 static uintptr_t _verify_oop_mask;
198 static uintptr_t _verify_oop_bits;
199
200 public:
201 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
202
203 // Known classes in the VM
204 static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); }
205 static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); }
206 static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); }
207 static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); }
208 static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); }
209 static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); }
210 static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); }
211 static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); }
212
213 static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; }
214
215 static Klass* typeArrayKlassObj(BasicType t) {
216 assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t));
217 assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t));
218 assert(_typeArrayKlassObjs[t] != NULL, "domain check");
219 return _typeArrayKlassObjs[t];
220 }
221
222 // Known objects in the VM
223 static oop int_mirror();
224 static oop float_mirror();
225 static oop double_mirror();
226 static oop byte_mirror();
227 static oop bool_mirror();
228 static oop char_mirror();
229 static oop long_mirror();
230 static oop short_mirror();
231 static oop void_mirror();
232
233 // Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY
234 // but including T_VOID, hence the index including T_VOID
235 static OopHandle _mirrors[T_VOID+1];
236
237 static oop java_mirror(BasicType t);
238 static void replace_mirror(BasicType t, oop obj);
239 static void clear_basic_type_mirrors();
240
241 static oop main_thread_group();
242 static void set_main_thread_group(oop group);
243
244 static oop system_thread_group();
245 static void set_system_thread_group(oop group);
246
247 static objArrayOop the_empty_class_array ();
248
249 static oop the_null_string();
250 static oop the_min_jint_string();
251
252 static oop null_ptr_exception_instance();
253 static oop arithmetic_exception_instance();
254 static oop virtual_machine_error_instance();
255 static oop vm_exception() { return virtual_machine_error_instance(); }
256
257 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
258 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); }
259 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); }
260
261 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); }
262 static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); }
263
264 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); }
265
266 static oop the_null_sentinel();
267 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
268
269 // Function to initialize these
270 static void initialize_known_methods(TRAPS);
271
272 static void create_preallocated_out_of_memory_errors(TRAPS);
273
274 // Reference pending list manipulation. Access is protected by
275 // Heap_lock. The getter, setter and predicate require the caller
276 // owns the lock. Swap is used by parallel non-concurrent reference
277 // processing threads, where some higher level controller owns
278 // Heap_lock, so requires the lock is locked, but not necessarily by
279 // the current thread.
280 static oop reference_pending_list();
281 static void clear_reference_pending_list();
282 static bool has_reference_pending_list();
283 static oop swap_reference_pending_list(oop list);
284
285 static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
286 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
287 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
288 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
289 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
290
291 // OutOfMemoryError support. Returns an error with the required message. The returned error
292 // may or may not have a backtrace. If error has a backtrace then the stack trace is already
293 // filled in.
294 static oop out_of_memory_error_java_heap();
295 static oop out_of_memory_error_c_heap();
296 static oop out_of_memory_error_metaspace();
297 static oop out_of_memory_error_class_metaspace();
298 static oop out_of_memory_error_array_size();
299 static oop out_of_memory_error_gc_overhead_limit();
300 static oop out_of_memory_error_realloc_objects();
301
302 // Throw default _out_of_memory_error_retry object as it will never propagate out of the VM
303 static oop out_of_memory_error_retry();
304 static oop delayed_stack_overflow_error_message();
305
306 // The particular choice of collected heap.
307 static CollectedHeap* heap() { return _collectedHeap; }
308
309 // Reserve Java heap and determine CompressedOops mode
310 static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment);
311
312 // Historic gc information
313 static size_t get_heap_free_at_last_gc() { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; }
314 static size_t get_heap_used_at_last_gc() { return _heap_used_at_last_gc; }
315 static void update_heap_info_at_gc();
316
317 // Global OopStorages
318 static OopStorage* vm_weak();
319 static OopStorage* vm_global();
320 static void oopstorage_init();
321
322 // Testers
323 static bool is_bootstrapping() { return _bootstrapping; }
324 static bool is_module_initialized() { return _module_initialized; }
325 static bool is_fully_initialized() { return _fully_initialized; }
326
327 static bool on_page_boundary(void* addr);
328 static bool should_fill_in_stack_trace(Handle throwable);
329 static void check_alignment(uintx size, uintx alignment, const char* name);
330
331 // Iteration
332
333 // Apply "f" to the addresses of all the direct heap pointers maintained
334 // as static fields of "Universe".
335 static void oops_do(OopClosure* f);
336
337 // CDS support
338 static void serialize(SerializeClosure* f);
339
340 // Apply "f" to all klasses for basic types (classes not present in
341 // SystemDictionary).
342 static void basic_type_classes_do(void f(Klass*));
343 static void basic_type_classes_do(KlassClosure* closure);
344 static void metaspace_pointers_do(MetaspaceClosure* it);
345
346 // Debugging
347 enum VERIFY_FLAGS {
348 Verify_Threads = 1,
349 Verify_Heap = 2,
350 Verify_SymbolTable = 4,
351 Verify_StringTable = 8,
352 Verify_CodeCache = 16,
353 Verify_SystemDictionary = 32,
354 Verify_ClassLoaderDataGraph = 64,
355 Verify_MetaspaceUtils = 128,
356 Verify_JNIHandles = 256,
357 Verify_CodeCacheOops = 512,
358 Verify_ResolvedMethodTable = 1024,
359 Verify_All = -1
360 };
361 static void initialize_verify_flags();
362 static bool should_verify_subset(uint subset);
363 static bool verify_in_progress() { return _verify_in_progress; }
364 static void verify(VerifyOption option, const char* prefix);
365 static void verify(const char* prefix) {
366 verify(VerifyOption_Default, prefix);
367 }
368 static void verify() {
369 verify("");
370 }
371
372 static int verify_count() { return _verify_count; }
373 static void print_on(outputStream* st);
374 static void print_heap_at_SIGBREAK();
375 static void print_heap_before_gc();
376 static void print_heap_after_gc();
377
378 // Change the number of dummy objects kept reachable by the full gc dummy
379 // array; this should trigger relocation in a sliding compaction collector.
380 debug_only(static bool release_fullgc_alot_dummy();)
381 // The non-oop pattern (see compiledIC.hpp, etc)
382 static void* non_oop_word();
383
384 // Oop verification (see MacroAssembler::verify_oop)
385 static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
386 static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
387 static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
388 static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
389
390 // Compiler support
391 static int base_vtable_size() { return _base_vtable_size; }
392 };
393
394 #endif // SHARE_MEMORY_UNIVERSE_HPP