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