1 /*
2 * Copyright (c) 1997, 2021, 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
47 // A helper class for caching a Method* when the user of the cache
48 // only cares about the latest version of the Method*. This cache safely
49 // interacts with the RedefineClasses API.
50
51 class LatestMethodCache : public CHeapObj<mtClass> {
52 // We save the Klass* and the idnum of Method* in order to get
53 // the current cached Method*.
54 private:
55 Klass* _klass;
56 int _method_idnum;
57
58 public:
59 LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
60 ~LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
61
62 void init(Klass* k, Method* m);
63 Klass* klass() const { return _klass; }
64 int method_idnum() const { return _method_idnum; }
65
66 Method* get_method();
67
68 // CDS support. Replace the klass in this with the archive version
69 // could use this for Enhanced Class Redefinition also.
70 void serialize(SerializeClosure* f) {
71 f->do_ptr((void**)&_klass);
72 }
73 void metaspace_pointers_do(MetaspaceClosure* it);
74 };
75
76 class Universe: AllStatic {
77 // Ugh. Universe is much too friendly.
78 friend class MarkSweep;
79 friend class oopDesc;
80 friend class ClassLoader;
81 friend class SystemDictionary;
82 friend class ReservedHeapSpace;
83 friend class VMStructs;
84 friend class VM_PopulateDumpSharedSpace;
85 friend class Metaspace;
86 friend class MetaspaceShared;
87 friend class vmClasses;
88
89 friend jint universe_init();
90 friend void universe2_init();
91 friend bool universe_post_init();
92 friend void universe_post_module_init();
93
94 private:
95 // Known classes in the VM
96 static Klass* _typeArrayKlassObjs[T_LONG+1];
97 static Klass* _objectArrayKlassObj;
98
99 // Known objects in the VM
100 static OopHandle _main_thread_group; // Reference to the main thread group object
101 static OopHandle _system_thread_group; // Reference to the system thread group object
102
103 static OopHandle _the_empty_class_array; // Canonicalized obj array of type java.lang.Class
104 static OopHandle _the_null_string; // A cache of "null" as a Java string
105 static OopHandle _the_min_jint_string; // A cache of "-2147483648" as a Java string
106
107 static OopHandle _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
108
109 // preallocated error objects (no backtrace)
110 static OopHandle _out_of_memory_errors;
111
112 // preallocated cause message for delayed StackOverflowError
113 static OopHandle _delayed_stack_overflow_error_message;
114
115 static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects
116 static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector
117 static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method
118 static LatestMethodCache* _throw_no_such_method_error_cache; // Unsafe.throwNoSuchMethodError() method
119 static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback
120
121 static Array<int>* _the_empty_int_array; // Canonicalized int array
122 static Array<u2>* _the_empty_short_array; // Canonicalized short array
123 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
124 static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
125 static Array<Method*>* _the_empty_method_array; // Canonicalized method array
126
127 static Array<Klass*>* _the_array_interfaces_array;
128
129 // array of preallocated error objects with backtrace
130 static OopHandle _preallocated_out_of_memory_error_array;
131
132 // number of preallocated error objects available for use
133 static volatile jint _preallocated_out_of_memory_error_avail_count;
134
135 static OopHandle _null_ptr_exception_instance; // preallocated exception object
136 static OopHandle _arithmetic_exception_instance; // preallocated exception object
137 static OopHandle _virtual_machine_error_instance; // preallocated exception object
138
139 // References waiting to be transferred to the ReferenceHandler
140 static OopHandle _reference_pending_list;
141
142 // The particular choice of collected heap.
143 static CollectedHeap* _collectedHeap;
144
145 static intptr_t _non_oop_bits;
146
147 // array of dummy objects used with +FullGCAlot
148 debug_only(static OopHandle _fullgc_alot_dummy_array;)
149 debug_only(static int _fullgc_alot_dummy_next;)
150
151 // Compiler/dispatch support
152 static int _base_vtable_size; // Java vtbl size of klass Object (in words)
153
154 // Initialization
155 static bool _bootstrapping; // true during genesis
156 static bool _module_initialized; // true after call_initPhase2 called
157 static bool _fully_initialized; // true after universe_init and initialize_vtables called
158
159 // the array of preallocated errors with backtraces
160 static objArrayOop preallocated_out_of_memory_errors();
161
162 static objArrayOop out_of_memory_errors();
163 // generate an out of memory error; if possible using an error with preallocated backtrace;
164 // otherwise return the given default error.
165 static oop gen_out_of_memory_error(oop default_err);
166
167 static OopStorage* _vm_weak;
168 static OopStorage* _vm_global;
169
170 static jint initialize_heap();
171 static void initialize_tlab();
172 static void initialize_basic_type_mirrors(TRAPS);
173 static void fixup_mirrors(TRAPS);
174
175 static void compute_base_vtable_size(); // compute vtable size of class Object
176
177 static void genesis(TRAPS); // Create the initial world
178
179 // Mirrors for primitive classes (created eagerly)
180 static oop check_mirror(oop m) {
181 assert(m != NULL, "mirror not initialized");
182 return m;
183 }
184
185 // Debugging
186 static int _verify_count; // number of verifies done
187 static long verify_flags;
188
189 static uintptr_t _verify_oop_mask;
190 static uintptr_t _verify_oop_bits;
191
192 public:
193 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
194
195 // Known classes in the VM
196 static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); }
197 static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); }
198 static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); }
199 static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); }
200 static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); }
201 static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); }
202 static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); }
203 static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); }
204
205 static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; }
206
207 static Klass* typeArrayKlassObj(BasicType t) {
208 assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t));
209 assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t));
210 assert(_typeArrayKlassObjs[t] != NULL, "domain check");
211 return _typeArrayKlassObjs[t];
212 }
213
214 // Known objects in the VM
215 static oop int_mirror();
216 static oop float_mirror();
217 static oop double_mirror();
218 static oop byte_mirror();
219 static oop bool_mirror();
220 static oop char_mirror();
221 static oop long_mirror();
222 static oop short_mirror();
223 static oop void_mirror();
224
225 // Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY
226 // but including T_VOID, hence the index including T_VOID
227 static OopHandle _mirrors[T_VOID+1];
228
229 static oop java_mirror(BasicType t);
230 static void replace_mirror(BasicType t, oop obj);
231
232 static oop main_thread_group();
233 static void set_main_thread_group(oop group);
234
235 static oop system_thread_group();
236 static void set_system_thread_group(oop group);
237
238 static objArrayOop the_empty_class_array ();
239
240 static oop the_null_string();
241 static oop the_min_jint_string();
242
243 static oop null_ptr_exception_instance();
244 static oop arithmetic_exception_instance();
245 static oop virtual_machine_error_instance();
246 static oop vm_exception() { return virtual_machine_error_instance(); }
247
248 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
249 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); }
250 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); }
251
252 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); }
253 static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); }
254
255 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); }
256
257 static oop the_null_sentinel();
258 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
259
260 // Function to initialize these
261 static void initialize_known_methods(TRAPS);
262
263 static void create_preallocated_out_of_memory_errors(TRAPS);
264
265 // Reference pending list manipulation. Access is protected by
266 // Heap_lock. The getter, setter and predicate require the caller
267 // owns the lock. Swap is used by parallel non-concurrent reference
268 // processing threads, where some higher level controller owns
269 // Heap_lock, so requires the lock is locked, but not necessarily by
270 // the current thread.
271 static oop reference_pending_list();
272 static void clear_reference_pending_list();
273 static bool has_reference_pending_list();
274 static oop swap_reference_pending_list(oop list);
275
276 static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
277 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
278 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
279 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
280 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
281
282 // OutOfMemoryError support. Returns an error with the required message. The returned error
283 // may or may not have a backtrace. If error has a backtrace then the stack trace is already
284 // filled in.
285 static oop out_of_memory_error_java_heap();
286 static oop out_of_memory_error_c_heap();
287 static oop out_of_memory_error_metaspace();
288 static oop out_of_memory_error_class_metaspace();
289 static oop out_of_memory_error_array_size();
290 static oop out_of_memory_error_gc_overhead_limit();
291 static oop out_of_memory_error_realloc_objects();
292
293 // Throw default _out_of_memory_error_retry object as it will never propagate out of the VM
294 static oop out_of_memory_error_retry();
295 static oop delayed_stack_overflow_error_message();
296
297 // The particular choice of collected heap.
298 static CollectedHeap* heap() { return _collectedHeap; }
299
300 DEBUG_ONLY(static bool is_gc_active();)
301 DEBUG_ONLY(static bool is_in_heap(const void* p);)
302 DEBUG_ONLY(static bool is_in_heap_or_null(const void* p) { return p == NULL || is_in_heap(p); })
303
304 // Reserve Java heap and determine CompressedOops mode
305 static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment);
306
307 // Global OopStorages
308 static OopStorage* vm_weak();
309 static OopStorage* vm_global();
310 static void oopstorage_init();
311
312 // Testers
313 static bool is_bootstrapping() { return _bootstrapping; }
314 static bool is_module_initialized() { return _module_initialized; }
315 static bool is_fully_initialized() { return _fully_initialized; }
316
317 static bool on_page_boundary(void* addr);
318 static bool should_fill_in_stack_trace(Handle throwable);
319 static void check_alignment(uintx size, uintx alignment, const char* name);
320
321 // CDS support
322 static void serialize(SerializeClosure* f);
323
324 // Apply "f" to all klasses for basic types (classes not present in
325 // SystemDictionary).
326 static void basic_type_classes_do(void f(Klass*));
327 static void basic_type_classes_do(KlassClosure* closure);
328 static void metaspace_pointers_do(MetaspaceClosure* it);
329
330 // Debugging
331 enum VERIFY_FLAGS {
332 Verify_Threads = 1,
333 Verify_Heap = 2,
334 Verify_SymbolTable = 4,
335 Verify_StringTable = 8,
336 Verify_CodeCache = 16,
337 Verify_SystemDictionary = 32,
338 Verify_ClassLoaderDataGraph = 64,
339 Verify_MetaspaceUtils = 128,
340 Verify_JNIHandles = 256,
341 Verify_CodeCacheOops = 512,
342 Verify_ResolvedMethodTable = 1024,
343 Verify_StringDedup = 2048,
344 Verify_All = -1
345 };
346 static void initialize_verify_flags();
347 static bool should_verify_subset(uint subset);
348 static void verify(VerifyOption option, const char* prefix);
349 static void verify(const char* prefix) {
350 verify(VerifyOption_Default, prefix);
351 }
352 static void verify() {
353 verify("");
354 }
355
356 static int verify_count() { return _verify_count; }
357 static void print_on(outputStream* st);
358 static void print_heap_at_SIGBREAK();
359
360 // Change the number of dummy objects kept reachable by the full gc dummy
361 // array; this should trigger relocation in a sliding compaction collector.
362 debug_only(static bool release_fullgc_alot_dummy();)
363 // The non-oop pattern (see compiledIC.hpp, etc)
364 static void* non_oop_word();
365 static bool contains_non_oop_word(void* p);
366
367 // Oop verification (see MacroAssembler::verify_oop)
368 static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
369 static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
370 static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
371 static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
372
373 // Compiler support
374 static int base_vtable_size() { return _base_vtable_size; }
375 };
376
377 #endif // SHARE_MEMORY_UNIVERSE_HPP