1 /*
2 * Copyright (c) 1997, 2023, 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.
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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 class ReservedHeapSpace;
46 class SerializeClosure;
47
48 // A helper class for caching a Method* when the user of the cache
49 // only cares about the latest version of the Method*. This cache safely
50 // interacts with the RedefineClasses API.
51
52 class LatestMethodCache : public CHeapObj<mtClass> {
53 // We save the Klass* and the idnum of Method* in order to get
54 // the current cached Method*.
55 private:
56 Klass* _klass;
57 int _method_idnum;
58
59 public:
60 LatestMethodCache() { _klass = nullptr; _method_idnum = -1; }
61 ~LatestMethodCache() { _klass = nullptr; _method_idnum = -1; }
62
63 void init(Klass* k, Method* m);
64 Klass* klass() const { return _klass; }
65 int method_idnum() const { return _method_idnum; }
66
67 Method* get_method();
68
69 // CDS support. Replace the klass in this with the archive version
70 // could use this for Enhanced Class Redefinition also.
71 void serialize(SerializeClosure* f);
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 friend class vmClasses;
87
88 friend jint universe_init();
89 friend void universe2_init();
90 friend bool universe_post_init();
91 friend void universe_post_module_init();
92
93 private:
94 // Known classes in the VM
95 static Klass* _typeArrayKlassObjs[T_LONG+1];
96 static Klass* _objectArrayKlassObj;
97 // Special int-Array that represents filler objects that are used by GC to overwrite
98 // dead objects. References to them are generally an error.
99 static Klass* _fillerArrayKlassObj;
100
101 // Known objects in the VM
102 static OopHandle _main_thread_group; // Reference to the main thread group object
103 static OopHandle _system_thread_group; // Reference to the system thread group object
104
105 static OopHandle _the_empty_class_array; // Canonicalized obj array of type java.lang.Class
106 static OopHandle _the_null_string; // A cache of "null" as a Java string
107 static OopHandle _the_min_jint_string; // A cache of "-2147483648" as a Java string
108
109 static OopHandle _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
110
111 // preallocated error objects (no backtrace)
112 static OopHandle _out_of_memory_errors;
113 static OopHandle _class_init_stack_overflow_error;
114
115 // preallocated cause message for delayed StackOverflowError
116 static OopHandle _delayed_stack_overflow_error_message;
117
118 static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects
119 static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector
120 static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method
121 static LatestMethodCache* _throw_no_such_method_error_cache; // Unsafe.throwNoSuchMethodError() method
122 static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback
123 static LatestMethodCache* _is_substitutable_cache; // ValueObjectMethods.isSubstitutable() method
124 static LatestMethodCache* _value_object_hash_code_cache; // ValueObjectMethods.valueObjectHashCode() method
125
126 static Array<int>* _the_empty_int_array; // Canonicalized int array
127 static Array<u2>* _the_empty_short_array; // Canonicalized short array
128 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
129 static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
130 static Array<Method*>* _the_empty_method_array; // Canonicalized method array
131
132 static Array<Klass*>* _the_array_interfaces_array;
133
134 // array of preallocated error objects with backtrace
135 static OopHandle _preallocated_out_of_memory_error_array;
136
137 // number of preallocated error objects available for use
138 static volatile jint _preallocated_out_of_memory_error_avail_count;
139
140 // preallocated message detail strings for error objects
141 static OopHandle _msg_metaspace;
142 static OopHandle _msg_class_metaspace;
143
144 static OopHandle _null_ptr_exception_instance; // preallocated exception object
145 static OopHandle _arithmetic_exception_instance; // preallocated exception object
146 static OopHandle _virtual_machine_error_instance; // preallocated exception object
147
148 // References waiting to be transferred to the ReferenceHandler
149 static OopHandle _reference_pending_list;
150
151 // The particular choice of collected heap.
152 static CollectedHeap* _collectedHeap;
153
154 static intptr_t _non_oop_bits;
155
156
157 // array of dummy objects used with +FullGCAlot
158 debug_only(static OopHandle _fullgc_alot_dummy_array;)
159 debug_only(static int _fullgc_alot_dummy_next;)
160
161 // Compiler/dispatch support
162 static int _base_vtable_size; // Java vtbl size of klass Object (in words)
163
164 // Initialization
165 static bool _bootstrapping; // true during genesis
166 static bool _module_initialized; // true after call_initPhase2 called
167 static bool _fully_initialized; // true after universe_init and initialize_vtables called
168
169 // the array of preallocated errors with backtraces
170 static objArrayOop preallocated_out_of_memory_errors();
171
172 static objArrayOop out_of_memory_errors();
173 // generate an out of memory error; if possible using an error with preallocated backtrace;
174 // otherwise return the given default error.
175 static oop gen_out_of_memory_error(oop default_err);
176
177 static OopStorage* _vm_weak;
178 static OopStorage* _vm_global;
179
180 static jint initialize_heap();
181 static void initialize_tlab();
182 static void initialize_basic_type_mirrors(TRAPS);
183 static void fixup_mirrors(TRAPS);
184
185 static void compute_base_vtable_size(); // compute vtable size of class Object
186
187 static void genesis(TRAPS); // Create the initial world
188
189 // Mirrors for primitive classes (created eagerly)
190 static oop check_mirror(oop m) {
191 assert(m != nullptr, "mirror not initialized");
192 return m;
193 }
194
195 // Debugging
196 static int _verify_count; // number of verifies done
197 static long verify_flags;
198
199 static uintptr_t _verify_oop_mask;
200 static uintptr_t _verify_oop_bits;
201
202 // Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY
203 // but including T_VOID, hence the index including T_VOID
204 static OopHandle _basic_type_mirrors[T_VOID+1];
205
206 #if INCLUDE_CDS_JAVA_HEAP
207 // Each slot i stores an index that can be used to restore _basic_type_mirrors[i]
208 // from the archive heap using HeapShared::get_root(int)
209 static int _archived_basic_type_mirror_indices[T_VOID+1];
210 #endif
211
212 public:
213 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
214 static void set_verify_data(uintptr_t mask, uintptr_t bits) PRODUCT_RETURN;
215
216 // Known classes in the VM
217 static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); }
218 static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); }
219 static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); }
220 static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); }
221 static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); }
222 static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); }
223 static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); }
224 static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); }
225
226 static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; }
227
228 static Klass* fillerArrayKlassObj() { return _fillerArrayKlassObj; }
229
230 static Klass* typeArrayKlassObj(BasicType t) {
231 assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t));
232 assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t));
233 assert(_typeArrayKlassObjs[t] != nullptr, "domain check");
234 return _typeArrayKlassObjs[t];
235 }
236
237 // Known objects in the VM
238 static oop int_mirror();
239 static oop float_mirror();
240 static oop double_mirror();
241 static oop byte_mirror();
242 static oop bool_mirror();
243 static oop char_mirror();
244 static oop long_mirror();
245 static oop short_mirror();
246 static oop void_mirror();
247
248 static oop java_mirror(BasicType t);
249
250 #if INCLUDE_CDS_JAVA_HEAP
251 static void set_archived_basic_type_mirror_index(BasicType t, int index);
252 static void update_archived_basic_type_mirrors();
253 #endif
254
255 static oop main_thread_group();
256 static void set_main_thread_group(oop group);
257
258 static oop system_thread_group();
259 static void set_system_thread_group(oop group);
260
261 static objArrayOop the_empty_class_array ();
262
263 static oop the_null_string();
264 static oop the_min_jint_string();
265
266 static oop null_ptr_exception_instance();
267 static oop arithmetic_exception_instance();
268 static oop virtual_machine_error_instance();
269 static oop vm_exception() { return virtual_machine_error_instance(); }
270
271 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
272 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); }
273 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); }
274
275 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); }
276 static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); }
277
278 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); }
279
280 static Method* is_substitutable_method() { return _is_substitutable_cache->get_method(); }
281 static Method* value_object_hash_code_method() { return _value_object_hash_code_cache->get_method(); }
282
283 static oop the_null_sentinel();
284 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
285
286 // Function to initialize these
287 static void initialize_known_methods(TRAPS);
288
289 static void create_preallocated_out_of_memory_errors(TRAPS);
290
291 // Reference pending list manipulation. Access is protected by
292 // Heap_lock. The getter, setter and predicate require the caller
293 // owns the lock. Swap is used by parallel non-concurrent reference
294 // processing threads, where some higher level controller owns
295 // Heap_lock, so requires the lock is locked, but not necessarily by
296 // the current thread.
297 static oop reference_pending_list();
298 static void clear_reference_pending_list();
299 static bool has_reference_pending_list();
300 static oop swap_reference_pending_list(oop list);
301
302 static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
303 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
304 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
305 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
306 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
307
308 // OutOfMemoryError support. Returns an error with the required message. The returned error
309 // may or may not have a backtrace. If error has a backtrace then the stack trace is already
310 // filled in.
311 static oop out_of_memory_error_java_heap();
312 static oop out_of_memory_error_c_heap();
313 static oop out_of_memory_error_metaspace();
314 static oop out_of_memory_error_class_metaspace();
315 static oop out_of_memory_error_array_size();
316 static oop out_of_memory_error_gc_overhead_limit();
317 static oop out_of_memory_error_realloc_objects();
318
319 // Throw default _out_of_memory_error_retry object as it will never propagate out of the VM
320 static oop out_of_memory_error_retry();
321 static oop delayed_stack_overflow_error_message();
322
323 // Saved StackOverflowError and OutOfMemoryError for use when
324 // class initialization can't create ExceptionInInitializerError.
325 static oop class_init_stack_overflow_error();
326 static oop class_init_out_of_memory_error();
327
328 // If it's a certain type of OOME object
329 static bool is_out_of_memory_error_metaspace(oop ex_obj);
330 static bool is_out_of_memory_error_class_metaspace(oop ex_obj);
331
332 // The particular choice of collected heap.
333 static CollectedHeap* heap() { return _collectedHeap; }
334
335 DEBUG_ONLY(static bool is_gc_active();)
336 DEBUG_ONLY(static bool is_in_heap(const void* p);)
337 DEBUG_ONLY(static bool is_in_heap_or_null(const void* p) { return p == nullptr || is_in_heap(p); })
338
339 // Reserve Java heap and determine CompressedOops mode
340 static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment);
341
342 // Global OopStorages
343 static OopStorage* vm_weak();
344 static OopStorage* vm_global();
345 static void oopstorage_init();
346
347 // Testers
348 static bool is_bootstrapping() { return _bootstrapping; }
349 static bool is_module_initialized() { return _module_initialized; }
350 static bool is_fully_initialized() { return _fully_initialized; }
351
352 static bool on_page_boundary(void* addr);
353 static bool should_fill_in_stack_trace(Handle throwable);
354 static void check_alignment(uintx size, uintx alignment, const char* name);
355
356 // CDS support
357 static void serialize(SerializeClosure* f);
358
359 // Apply the closure to all klasses for basic types (classes not present in
360 // SystemDictionary).
361 static void basic_type_classes_do(KlassClosure* closure);
362 static void metaspace_pointers_do(MetaspaceClosure* it);
363
364 // Debugging
365 enum VERIFY_FLAGS {
366 Verify_Threads = 1,
367 Verify_Heap = 2,
368 Verify_SymbolTable = 4,
369 Verify_StringTable = 8,
370 Verify_CodeCache = 16,
371 Verify_SystemDictionary = 32,
372 Verify_ClassLoaderDataGraph = 64,
373 Verify_MetaspaceUtils = 128,
374 Verify_JNIHandles = 256,
375 Verify_CodeCacheOops = 512,
376 Verify_ResolvedMethodTable = 1024,
377 Verify_StringDedup = 2048,
378 Verify_All = -1
379 };
380 static void initialize_verify_flags();
381 static bool should_verify_subset(uint subset);
382 static void verify(VerifyOption option, const char* prefix);
383 static void verify(const char* prefix) {
384 verify(VerifyOption::Default, prefix);
385 }
386 static void verify() {
387 verify("");
388 }
389
390 static int verify_count() { return _verify_count; }
391 static void print_on(outputStream* st);
392 static void print_heap_at_SIGBREAK();
393
394 // Change the number of dummy objects kept reachable by the full gc dummy
395 // array; this should trigger relocation in a sliding compaction collector.
396 debug_only(static bool release_fullgc_alot_dummy();)
397 // The non-oop pattern (see compiledIC.hpp, etc)
398 static void* non_oop_word();
399 static bool contains_non_oop_word(void* p);
400
401 // Oop verification (see MacroAssembler::verify_oop)
402 static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
403 static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
404 static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
405 static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
406
407 // Compiler support
408 static int base_vtable_size() { return _base_vtable_size; }
409 };
410
411 #endif // SHARE_MEMORY_UNIVERSE_HPP