1 /*
2 * Copyright (c) 1997, 2024, 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
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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.
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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 class Universe: AllStatic {
49 // Ugh. Universe is much too friendly.
50 friend class SerialFullGC;
51 friend class oopDesc;
52 friend class ClassLoader;
53 friend class SystemDictionary;
54 friend class ReservedHeapSpace;
55 friend class VMStructs;
56 friend class VM_PopulateDumpSharedSpace;
57 friend class Metaspace;
58 friend class MetaspaceShared;
59 friend class vmClasses;
60
61 friend jint universe_init();
62 friend void universe2_init();
63 friend bool universe_post_init();
64 friend void universe_post_module_init();
65
66 private:
67 // Known classes in the VM
68 static TypeArrayKlass* _typeArrayKlasses[T_LONG+1];
69 static ObjArrayKlass* _objectArrayKlass;
70 // Special int-Array that represents filler objects that are used by GC to overwrite
71 // dead objects. References to them are generally an error.
72 static Klass* _fillerArrayKlass;
73
74 // Known objects in the VM
75 static OopHandle _main_thread_group; // Reference to the main thread group object
76 static OopHandle _system_thread_group; // Reference to the system thread group object
77
78 static OopHandle _the_empty_class_array; // Canonicalized obj array of type java.lang.Class
79 static OopHandle _the_null_string; // A cache of "null" as a Java string
80 static OopHandle _the_min_jint_string; // A cache of "-2147483648" as a Java string
81
82 static OopHandle _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
83
84 // preallocated error objects (no backtrace)
85 static OopHandle _out_of_memory_errors;
86 static OopHandle _class_init_stack_overflow_error;
87
88 // preallocated cause message for delayed StackOverflowError
89 static OopHandle _delayed_stack_overflow_error_message;
90
91 static Array<int>* _the_empty_int_array; // Canonicalized int array
92 static Array<u2>* _the_empty_short_array; // Canonicalized short array
93 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
94 static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
95 static Array<Method*>* _the_empty_method_array; // Canonicalized method array
96
97 static Array<Klass*>* _the_array_interfaces_array;
98
99 static uintx _the_array_interfaces_bitmap;
100 static uintx _the_empty_klass_bitmap;
101
102 // array of preallocated error objects with backtrace
103 static OopHandle _preallocated_out_of_memory_error_array;
104
105 // number of preallocated error objects available for use
106 static volatile jint _preallocated_out_of_memory_error_avail_count;
107
108 // preallocated message detail strings for error objects
109 static OopHandle _msg_metaspace;
110 static OopHandle _msg_class_metaspace;
111
112 // References waiting to be transferred to the ReferenceHandler
113 static OopHandle _reference_pending_list;
114
115 // The particular choice of collected heap.
116 static CollectedHeap* _collectedHeap;
117
118 static intptr_t _non_oop_bits;
119
120
121 // array of dummy objects used with +FullGCAlot
122 debug_only(static OopHandle _fullgc_alot_dummy_array;)
123 debug_only(static int _fullgc_alot_dummy_next;)
124
125 // Compiler/dispatch support
126 static int _base_vtable_size; // Java vtbl size of klass Object (in words)
127
128 // Initialization
129 static bool _bootstrapping; // true during genesis
130 static bool _module_initialized; // true after call_initPhase2 called
131 static bool _fully_initialized; // true after universe_init and initialize_vtables called
132
133 // the array of preallocated errors with backtraces
134 static objArrayOop preallocated_out_of_memory_errors();
135
136 static objArrayOop out_of_memory_errors();
137 // generate an out of memory error; if possible using an error with preallocated backtrace;
138 // otherwise return the given default error.
139 static oop gen_out_of_memory_error(oop default_err);
140
141 static OopStorage* _vm_weak;
142 static OopStorage* _vm_global;
143
144 static jint initialize_heap();
145 static void initialize_tlab();
146 static void initialize_basic_type_mirrors(TRAPS);
147 static void fixup_mirrors(TRAPS);
148
149 static void compute_base_vtable_size(); // compute vtable size of class Object
150
151 static void genesis(TRAPS); // Create the initial world
152
153 // Mirrors for primitive classes (created eagerly)
154 static oop check_mirror(oop m) {
155 assert(m != nullptr, "mirror not initialized");
156 return m;
157 }
158
159 // Debugging
160 static int _verify_count; // number of verifies done
161 static long verify_flags;
162
163 static uintptr_t _verify_oop_mask;
164 static uintptr_t _verify_oop_bits;
165
166 // Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY
167 // but including T_VOID, hence the index including T_VOID
168 static OopHandle _basic_type_mirrors[T_VOID+1];
169
170 #if INCLUDE_CDS_JAVA_HEAP
171 // Each slot i stores an index that can be used to restore _basic_type_mirrors[i]
172 // from the archive heap using HeapShared::get_root(int)
173 static int _archived_basic_type_mirror_indices[T_VOID+1];
174 #endif
175
176 public:
177 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
178 static void set_verify_data(uintptr_t mask, uintptr_t bits) PRODUCT_RETURN;
179
180 // Known classes in the VM
181 static TypeArrayKlass* boolArrayKlass() { return typeArrayKlass(T_BOOLEAN); }
182 static TypeArrayKlass* byteArrayKlass() { return typeArrayKlass(T_BYTE); }
183 static TypeArrayKlass* charArrayKlass() { return typeArrayKlass(T_CHAR); }
184 static TypeArrayKlass* intArrayKlass() { return typeArrayKlass(T_INT); }
185 static TypeArrayKlass* shortArrayKlass() { return typeArrayKlass(T_SHORT); }
186 static TypeArrayKlass* longArrayKlass() { return typeArrayKlass(T_LONG); }
187 static TypeArrayKlass* floatArrayKlass() { return typeArrayKlass(T_FLOAT); }
188 static TypeArrayKlass* doubleArrayKlass() { return typeArrayKlass(T_DOUBLE); }
189
190 static ObjArrayKlass* objectArrayKlass() { return _objectArrayKlass; }
191
192 static Klass* fillerArrayKlass() { return _fillerArrayKlass; }
193
194 static TypeArrayKlass* typeArrayKlass(BasicType t) {
195 assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t));
196 assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t));
197 assert(_typeArrayKlasses[t] != nullptr, "domain check");
198 return _typeArrayKlasses[t];
199 }
200
201 // Known objects in the VM
202 static oop int_mirror();
203 static oop float_mirror();
204 static oop double_mirror();
205 static oop byte_mirror();
206 static oop bool_mirror();
207 static oop char_mirror();
208 static oop long_mirror();
209 static oop short_mirror();
210 static oop void_mirror();
211
212 static oop java_mirror(BasicType t);
213
214 static void load_archived_object_instances() NOT_CDS_JAVA_HEAP_RETURN;
215 #if INCLUDE_CDS_JAVA_HEAP
216 static void set_archived_basic_type_mirror_index(BasicType t, int index);
217 static void archive_exception_instances();
218 #endif
219
220 static oop main_thread_group();
221 static void set_main_thread_group(oop group);
222
223 static oop system_thread_group();
224 static void set_system_thread_group(oop group);
225
226 static objArrayOop the_empty_class_array ();
227
228 static oop the_null_string();
229 static oop the_min_jint_string();
230
231 static oop null_ptr_exception_instance();
232 static oop arithmetic_exception_instance();
233 static oop internal_error_instance();
234 static oop array_index_out_of_bounds_exception_instance();
235 static oop array_store_exception_instance();
236 static oop class_cast_exception_instance();
237 static oop vm_exception() { return internal_error_instance(); }
238
239 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
240 static uintx the_array_interfaces_bitmap() { return _the_array_interfaces_bitmap; }
241
242 static Method* finalizer_register_method();
243 static Method* loader_addClass_method();
244 static Method* throw_illegal_access_error();
245 static Method* throw_no_such_method_error();
246 static Method* do_stack_walk_method();
247
248 static Method* is_substitutable_method();
249 static Method* value_object_hash_code_method();
250
251 static oop the_null_sentinel();
252 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
253
254 // Function to initialize these
255 static void initialize_known_methods(JavaThread* current);
256
257 static void create_preallocated_out_of_memory_errors(TRAPS);
258
259 // Reference pending list manipulation. Access is protected by
260 // Heap_lock. The getter, setter and predicate require the caller
261 // owns the lock. Swap is used by parallel non-concurrent reference
262 // processing threads, where some higher level controller owns
263 // Heap_lock, so requires the lock is locked, but not necessarily by
264 // the current thread.
265 static oop reference_pending_list();
266 static void clear_reference_pending_list();
267 static bool has_reference_pending_list();
268 static oop swap_reference_pending_list(oop list);
269
270 static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
271 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
272 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
273 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
274 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
275
276 static uintx the_empty_klass_bitmap() { return _the_empty_klass_bitmap; }
277
278 // OutOfMemoryError support. Returns an error with the required message. The returned error
279 // may or may not have a backtrace. If error has a backtrace then the stack trace is already
280 // filled in.
281 static oop out_of_memory_error_java_heap();
282 static oop out_of_memory_error_java_heap_without_backtrace();
283 static oop out_of_memory_error_c_heap();
284 static oop out_of_memory_error_metaspace();
285 static oop out_of_memory_error_class_metaspace();
286 static oop out_of_memory_error_array_size();
287 static oop out_of_memory_error_gc_overhead_limit();
288 static oop out_of_memory_error_realloc_objects();
289
290 static oop delayed_stack_overflow_error_message();
291
292 // Saved StackOverflowError and OutOfMemoryError for use when
293 // class initialization can't create ExceptionInInitializerError.
294 static oop class_init_stack_overflow_error();
295 static oop class_init_out_of_memory_error();
296
297 // If it's a certain type of OOME object
298 static bool is_out_of_memory_error_metaspace(oop ex_obj);
299 static bool is_out_of_memory_error_class_metaspace(oop ex_obj);
300
301 // The particular choice of collected heap.
302 static CollectedHeap* heap() { return _collectedHeap; }
303
304 DEBUG_ONLY(static bool is_stw_gc_active();)
305 DEBUG_ONLY(static bool is_in_heap(const void* p);)
306 DEBUG_ONLY(static bool is_in_heap_or_null(const void* p) { return p == nullptr || is_in_heap(p); })
307
308 // Reserve Java heap and determine CompressedOops mode
309 static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment);
310
311 // Global OopStorages
312 static OopStorage* vm_weak();
313 static OopStorage* vm_global();
314 static void oopstorage_init();
315
316 // Testers
317 static bool is_bootstrapping() { return _bootstrapping; }
318 static bool is_module_initialized() { return _module_initialized; }
319 static bool is_fully_initialized() { return _fully_initialized; }
320
321 static bool on_page_boundary(void* addr);
322 static bool should_fill_in_stack_trace(Handle throwable);
323 static void check_alignment(uintx size, uintx alignment, const char* name);
324
325 // CDS support
326 static void serialize(SerializeClosure* f);
327
328 // Apply the closure to all klasses for basic types (classes not present in
329 // SystemDictionary).
330 static void basic_type_classes_do(KlassClosure* closure);
331 static void metaspace_pointers_do(MetaspaceClosure* it);
332
333 // Debugging
334 enum VERIFY_FLAGS {
335 Verify_Threads = 1,
336 Verify_Heap = 2,
337 Verify_SymbolTable = 4,
338 Verify_StringTable = 8,
339 Verify_CodeCache = 16,
340 Verify_SystemDictionary = 32,
341 Verify_ClassLoaderDataGraph = 64,
342 Verify_MetaspaceUtils = 128,
343 Verify_JNIHandles = 256,
344 Verify_CodeCacheOops = 512,
345 Verify_ResolvedMethodTable = 1024,
346 Verify_StringDedup = 2048,
347 Verify_All = -1
348 };
349 static void initialize_verify_flags();
350 static bool should_verify_subset(uint subset);
351 static void verify(VerifyOption option, const char* prefix);
352 static void verify(const char* prefix) {
353 verify(VerifyOption::Default, prefix);
354 }
355 static void verify() {
356 verify("");
357 }
358
359 static int verify_count() { return _verify_count; }
360 static void print_on(outputStream* st);
361 static void print_heap_at_SIGBREAK();
362
363 // Change the number of dummy objects kept reachable by the full gc dummy
364 // array; this should trigger relocation in a sliding compaction collector.
365 debug_only(static bool release_fullgc_alot_dummy();)
366 // The non-oop pattern (see compiledIC.hpp, etc)
367 static void* non_oop_word();
368 static bool contains_non_oop_word(void* p);
369
370 // Oop verification (see MacroAssembler::verify_oop)
371 static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
372 static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
373 static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
374 static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
375
376 // Compiler support
377 static int base_vtable_size() { return _base_vtable_size; }
378 };
379
380 #endif // SHARE_MEMORY_UNIVERSE_HPP