1/*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 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 "runtime/handles.hpp"
31#include "utilities/growableArray.hpp"
32
33// Universe is a name space holding known system classes and objects in the VM.
34//
35// Loaded classes are accessible through the SystemDictionary.
36//
37// The object heap is allocated and accessed through Universe, and various allocation
38// support is provided. Allocation by the interpreter and compiled code is done inline
39// and bails out to Scavenge::invoke_and_allocate.
40
41class CollectedHeap;
42class DeferredObjAllocEvent;
43
44
45// A helper class for caching a Method* when the user of the cache
46// only cares about the latest version of the Method*. This cache safely
47// interacts with the RedefineClasses API.
48
49class LatestMethodCache : public CHeapObj<mtClass> {
50 // We save the Klass* and the idnum of Method* in order to get
51 // the current cached Method*.
52 private:
53 Klass* _klass;
54 int _method_idnum;
55
56 public:
57 LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
58 ~LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
59
60 void init(Klass* k, Method* m);
61 Klass* klass() const { return _klass; }
62 int method_idnum() const { return _method_idnum; }
63
64 Method* get_method();
65
66 // CDS support. Replace the klass in this with the archive version
67 // could use this for Enhanced Class Redefinition also.
68 void serialize(SerializeClosure* f) {
69 f->do_ptr((void**)&_klass);
70 }
71 void metaspace_pointers_do(MetaspaceClosure* it);
72};
73
74class Universe: AllStatic {
75 // Ugh. Universe is much too friendly.
76 friend class MarkSweep;
77 friend class oopDesc;
78 friend class ClassLoader;
79 friend class SystemDictionary;
80 friend class ReservedHeapSpace;
81 friend class VMStructs;
82 friend class VM_PopulateDumpSharedSpace;
83 friend class Metaspace;
84 friend class MetaspaceShared;
85
86 friend jint universe_init();
87 friend void universe2_init();
88 friend bool universe_post_init();
89 friend void universe_post_module_init();
90
91 private:
92 // Known classes in the VM
93 static Klass* _typeArrayKlassObjs[T_LONG+1];
94 static Klass* _objectArrayKlassObj;
95
96 // Known objects in the VM
97
98 // Primitive objects
99 static oop _int_mirror;
100 static oop _float_mirror;
101 static oop _double_mirror;
102 static oop _byte_mirror;
103 static oop _bool_mirror;
104 static oop _char_mirror;
105 static oop _long_mirror;
106 static oop _short_mirror;
107 static oop _void_mirror;
108
109 static oop _main_thread_group; // Reference to the main thread group object
110 static oop _system_thread_group; // Reference to the system thread group object
111
112 static objArrayOop _the_empty_class_klass_array; // Canonicalized obj array of type java.lang.Class
113 static oop _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
114 static oop _the_null_string; // A cache of "null" as a Java string
115 static oop _the_min_jint_string; // A cache of "-2147483648" as a Java string
116 static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects
117 static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector
118 static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method
119 static LatestMethodCache* _throw_no_such_method_error_cache; // Unsafe.throwNoSuchMethodError() method
120 static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback
121
122 // preallocated error objects (no backtrace)
123 static oop _out_of_memory_error_java_heap;
124 static oop _out_of_memory_error_metaspace;
125 static oop _out_of_memory_error_class_metaspace;
126 static oop _out_of_memory_error_array_size;
127 static oop _out_of_memory_error_gc_overhead_limit;
128 static oop _out_of_memory_error_realloc_objects;
129 static oop _out_of_memory_error_retry;
130
131 // preallocated cause message for delayed StackOverflowError
132 static oop _delayed_stack_overflow_error_message;
133
134 static Array<int>* _the_empty_int_array; // Canonicalized int array
135 static Array<u2>* _the_empty_short_array; // Canonicalized short array
136 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
137 static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
138 static Array<Method*>* _the_empty_method_array; // Canonicalized method array
139
140 static Array<Klass*>* _the_array_interfaces_array;
141
142 // array of preallocated error objects with backtrace
143 static objArrayOop _preallocated_out_of_memory_error_array;
144
145 // number of preallocated error objects available for use
146 static volatile jint _preallocated_out_of_memory_error_avail_count;
147
148 static oop _null_ptr_exception_instance; // preallocated exception object
149 static oop _arithmetic_exception_instance; // preallocated exception object
150 static oop _virtual_machine_error_instance; // preallocated exception object
151 // The object used as an exception dummy when exceptions are thrown for
152 // the vm thread.
153 static oop _vm_exception;
154
155 // References waiting to be transferred to the ReferenceHandler
156 static oop _reference_pending_list;
157
158 // The particular choice of collected heap.
159 static CollectedHeap* _collectedHeap;
160
161 static intptr_t _non_oop_bits;
162
163 // array of dummy objects used with +FullGCAlot
164 debug_only(static objArrayOop _fullgc_alot_dummy_array;)
165 // index of next entry to clear
166 debug_only(static int _fullgc_alot_dummy_next;)
167
168 // Compiler/dispatch support
169 static int _base_vtable_size; // Java vtbl size of klass Object (in words)
170
171 // Initialization
172 static bool _bootstrapping; // true during genesis
173 static bool _module_initialized; // true after call_initPhase2 called
174 static bool _fully_initialized; // true after universe_init and initialize_vtables called
175
176 // the array of preallocated errors with backtraces
177 static objArrayOop preallocated_out_of_memory_errors() { return _preallocated_out_of_memory_error_array; }
178
179 // generate an out of memory error; if possible using an error with preallocated backtrace;
180 // otherwise return the given default error.
181 static oop gen_out_of_memory_error(oop default_err);
182
183 // Historic gc information
184 static size_t _heap_capacity_at_last_gc;
185 static size_t _heap_used_at_last_gc;
186
187 static jint initialize_heap();
188 static void initialize_tlab();
189 static void initialize_basic_type_mirrors(TRAPS);
190 static void fixup_mirrors(TRAPS);
191
192 static void reinitialize_vtable_of(Klass* k, TRAPS);
193 static void reinitialize_vtables(TRAPS);
194 static void reinitialize_itables(TRAPS);
195 static void compute_base_vtable_size(); // compute vtable size of class Object
196
197 static void genesis(TRAPS); // Create the initial world
198
199 // Mirrors for primitive classes (created eagerly)
200 static oop check_mirror(oop m) {
201 assert(m != NULL, "mirror not initialized");
202 return m;
203 }
204
205 // Debugging
206 static int _verify_count; // number of verifies done
207
208 // True during call to verify(). Should only be set/cleared in verify().
209 static bool _verify_in_progress;
210 static long verify_flags;
211
212 static uintptr_t _verify_oop_mask;
213 static uintptr_t _verify_oop_bits;
214
215 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
216
217 public:
218 // Known classes in the VM
219 static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); }
220 static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); }
221 static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); }
222 static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); }
223 static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); }
224 static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); }
225 static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); }
226 static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); }
227
228 static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; }
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] != NULL, "domain check");
234 return _typeArrayKlassObjs[t];
235 }
236
237 // Known objects in the VM
238 static oop int_mirror() { return check_mirror(_int_mirror); }
239 static oop float_mirror() { return check_mirror(_float_mirror); }
240 static oop double_mirror() { return check_mirror(_double_mirror); }
241 static oop byte_mirror() { return check_mirror(_byte_mirror); }
242 static oop bool_mirror() { return check_mirror(_bool_mirror); }
243 static oop char_mirror() { return check_mirror(_char_mirror); }
244 static oop long_mirror() { return check_mirror(_long_mirror); }
245 static oop short_mirror() { return check_mirror(_short_mirror); }
246 static oop void_mirror() { return check_mirror(_void_mirror); }
247
248 static void set_int_mirror(oop m) { _int_mirror = m; }
249 static void set_float_mirror(oop m) { _float_mirror = m; }
250 static void set_double_mirror(oop m) { _double_mirror = m; }
251 static void set_byte_mirror(oop m) { _byte_mirror = m; }
252 static void set_bool_mirror(oop m) { _bool_mirror = m; }
253 static void set_char_mirror(oop m) { _char_mirror = m; }
254 static void set_long_mirror(oop m) { _long_mirror = m; }
255 static void set_short_mirror(oop m) { _short_mirror = m; }
256 static void set_void_mirror(oop m) { _void_mirror = m; }
257
258 // table of same
259 static oop _mirrors[T_VOID+1];
260
261 static oop java_mirror(BasicType t) {
262 assert((uint)t < T_VOID+1, "range check");
263 return check_mirror(_mirrors[t]);
264 }
265 static oop main_thread_group() { return _main_thread_group; }
266 static void set_main_thread_group(oop group) { _main_thread_group = group;}
267
268 static oop system_thread_group() { return _system_thread_group; }
269 static void set_system_thread_group(oop group) { _system_thread_group = group;}
270
271 static objArrayOop the_empty_class_klass_array () { return _the_empty_class_klass_array; }
272 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
273 static oop the_null_string() { return _the_null_string; }
274 static oop the_min_jint_string() { return _the_min_jint_string; }
275
276 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); }
277 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); }
278
279 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); }
280 static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); }
281
282 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); }
283
284 static oop the_null_sentinel() { return _the_null_sentinel; }
285 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
286
287 // Function to initialize these
288 static void initialize_known_methods(TRAPS);
289
290 static oop null_ptr_exception_instance() { return _null_ptr_exception_instance; }
291 static oop arithmetic_exception_instance() { return _arithmetic_exception_instance; }
292 static oop virtual_machine_error_instance() { return _virtual_machine_error_instance; }
293 static oop vm_exception() { return _vm_exception; }
294
295 // Reference pending list manipulation. Access is protected by
296 // Heap_lock. The getter, setter and predicate require the caller
297 // owns the lock. Swap is used by parallel non-concurrent reference
298 // processing threads, where some higher level controller owns
299 // Heap_lock, so requires the lock is locked, but not necessarily by
300 // the current thread.
301 static oop reference_pending_list();
302 static void set_reference_pending_list(oop list);
303 static bool has_reference_pending_list();
304 static oop swap_reference_pending_list(oop list);
305
306 static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
307 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
308 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
309 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
310 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
311
312 // OutOfMemoryError support. Returns an error with the required message. The returned error
313 // may or may not have a backtrace. If error has a backtrace then the stack trace is already
314 // filled in.
315 static oop out_of_memory_error_java_heap() { return gen_out_of_memory_error(_out_of_memory_error_java_heap); }
316 static oop out_of_memory_error_metaspace() { return gen_out_of_memory_error(_out_of_memory_error_metaspace); }
317 static oop out_of_memory_error_class_metaspace() { return gen_out_of_memory_error(_out_of_memory_error_class_metaspace); }
318 static oop out_of_memory_error_array_size() { return gen_out_of_memory_error(_out_of_memory_error_array_size); }
319 static oop out_of_memory_error_gc_overhead_limit() { return gen_out_of_memory_error(_out_of_memory_error_gc_overhead_limit); }
320 static oop out_of_memory_error_realloc_objects() { return gen_out_of_memory_error(_out_of_memory_error_realloc_objects); }
321 // Throw default _out_of_memory_error_retry object as it will never propagate out of the VM
322 static oop out_of_memory_error_retry() { return _out_of_memory_error_retry; }
323 static oop delayed_stack_overflow_error_message() { return _delayed_stack_overflow_error_message; }
324
325 // The particular choice of collected heap.
326 static CollectedHeap* heap() { return _collectedHeap; }
327
328 // Reserve Java heap and determine CompressedOops mode
329 static ReservedSpace reserve_heap(size_t heap_size, size_t alignment);
330
331 // Historic gc information
332 static size_t get_heap_free_at_last_gc() { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; }
333 static size_t get_heap_used_at_last_gc() { return _heap_used_at_last_gc; }
334 static void update_heap_info_at_gc();
335
336 // Testers
337 static bool is_bootstrapping() { return _bootstrapping; }
338 static bool is_module_initialized() { return _module_initialized; }
339 static bool is_fully_initialized() { return _fully_initialized; }
340
341 static bool on_page_boundary(void* addr);
342 static bool should_fill_in_stack_trace(Handle throwable);
343 static void check_alignment(uintx size, uintx alignment, const char* name);
344
345 // Iteration
346
347 // Apply "f" to the addresses of all the direct heap pointers maintained
348 // as static fields of "Universe".
349 static void oops_do(OopClosure* f);
350
351 // CDS support
352 static void serialize(SerializeClosure* f);
353
354 // Apply "f" to all klasses for basic types (classes not present in
355 // SystemDictionary).
356 static void basic_type_classes_do(void f(Klass*));
357 static void basic_type_classes_do(KlassClosure* closure);
358 static void metaspace_pointers_do(MetaspaceClosure* it);
359
360 // Debugging
361 enum VERIFY_FLAGS {
362 Verify_Threads = 1,
363 Verify_Heap = 2,
364 Verify_SymbolTable = 4,
365 Verify_StringTable = 8,
366 Verify_CodeCache = 16,
367 Verify_SystemDictionary = 32,
368 Verify_ClassLoaderDataGraph = 64,
369 Verify_MetaspaceUtils = 128,
370 Verify_JNIHandles = 256,
371 Verify_CodeCacheOops = 512,
372 Verify_ResolvedMethodTable = 1024,
373 Verify_All = -1
374 };
375 static void initialize_verify_flags();
376 static bool should_verify_subset(uint subset);
377 static bool verify_in_progress() { return _verify_in_progress; }
378 static void verify(VerifyOption option, const char* prefix);
379 static void verify(const char* prefix) {
380 verify(VerifyOption_Default, prefix);
381 }
382 static void verify() {
383 verify("");
384 }
385
386 static int verify_count() { return _verify_count; }
387 static void print_on(outputStream* st);
388 static void print_heap_at_SIGBREAK();
389 static void print_heap_before_gc();
390 static void print_heap_after_gc();
391
392 // Change the number of dummy objects kept reachable by the full gc dummy
393 // array; this should trigger relocation in a sliding compaction collector.
394 debug_only(static bool release_fullgc_alot_dummy();)
395 // The non-oop pattern (see compiledIC.hpp, etc)
396 static void* non_oop_word();
397
398 // Oop verification (see MacroAssembler::verify_oop)
399 static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
400 static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
401 static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
402 static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
403
404 // Compiler support
405 static int base_vtable_size() { return _base_vtable_size; }
406};
407
408#endif // SHARE_MEMORY_UNIVERSE_HPP
409