1 /* 2 * Copyright (c) 1997, 2022, 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. 22 * 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 // preallocated message detail strings for error objects 136 static OopHandle _msg_metaspace; 137 static OopHandle _msg_class_metaspace; 138 139 static OopHandle _null_ptr_exception_instance; // preallocated exception object 140 static OopHandle _arithmetic_exception_instance; // preallocated exception object 141 static OopHandle _virtual_machine_error_instance; // preallocated exception object 142 143 // References waiting to be transferred to the ReferenceHandler 144 static OopHandle _reference_pending_list; 145 146 // The particular choice of collected heap. 147 static CollectedHeap* _collectedHeap; 148 149 static intptr_t _non_oop_bits; 150 151 // array of dummy objects used with +FullGCAlot 152 debug_only(static OopHandle _fullgc_alot_dummy_array;) 153 debug_only(static int _fullgc_alot_dummy_next;) 154 155 // Compiler/dispatch support 156 static int _base_vtable_size; // Java vtbl size of klass Object (in words) 157 158 // Initialization 159 static bool _bootstrapping; // true during genesis 160 static bool _module_initialized; // true after call_initPhase2 called 161 static bool _fully_initialized; // true after universe_init and initialize_vtables called 162 163 // the array of preallocated errors with backtraces 164 static objArrayOop preallocated_out_of_memory_errors(); 165 166 static objArrayOop out_of_memory_errors(); 167 // generate an out of memory error; if possible using an error with preallocated backtrace; 168 // otherwise return the given default error. 169 static oop gen_out_of_memory_error(oop default_err); 170 171 static OopStorage* _vm_weak; 172 static OopStorage* _vm_global; 173 174 static jint initialize_heap(); 175 static void initialize_tlab(); 176 static void initialize_basic_type_mirrors(TRAPS); 177 static void fixup_mirrors(TRAPS); 178 179 static void compute_base_vtable_size(); // compute vtable size of class Object 180 181 static void genesis(TRAPS); // Create the initial world 182 183 // Mirrors for primitive classes (created eagerly) 184 static oop check_mirror(oop m) { 185 assert(m != NULL, "mirror not initialized"); 186 return m; 187 } 188 189 // Debugging 190 static int _verify_count; // number of verifies done 191 static long verify_flags; 192 193 static uintptr_t _verify_oop_mask; 194 static uintptr_t _verify_oop_bits; 195 196 public: 197 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN; 198 199 // Known classes in the VM 200 static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); } 201 static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); } 202 static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); } 203 static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); } 204 static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); } 205 static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); } 206 static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); } 207 static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); } 208 209 static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; } 210 211 static Klass* typeArrayKlassObj(BasicType t) { 212 assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t)); 213 assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t)); 214 assert(_typeArrayKlassObjs[t] != NULL, "domain check"); 215 return _typeArrayKlassObjs[t]; 216 } 217 218 // Known objects in the VM 219 static oop int_mirror(); 220 static oop float_mirror(); 221 static oop double_mirror(); 222 static oop byte_mirror(); 223 static oop bool_mirror(); 224 static oop char_mirror(); 225 static oop long_mirror(); 226 static oop short_mirror(); 227 static oop void_mirror(); 228 229 // Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY 230 // but including T_VOID, hence the index including T_VOID 231 static OopHandle _mirrors[T_VOID+1]; 232 233 static oop java_mirror(BasicType t); 234 static void replace_mirror(BasicType t, oop obj); 235 236 static oop main_thread_group(); 237 static void set_main_thread_group(oop group); 238 239 static oop system_thread_group(); 240 static void set_system_thread_group(oop group); 241 242 static objArrayOop the_empty_class_array (); 243 244 static oop the_null_string(); 245 static oop the_min_jint_string(); 246 247 static oop null_ptr_exception_instance(); 248 static oop arithmetic_exception_instance(); 249 static oop virtual_machine_error_instance(); 250 static oop vm_exception() { return virtual_machine_error_instance(); } 251 252 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; } 253 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); } 254 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); } 255 256 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); } 257 static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); } 258 259 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); } 260 261 static oop the_null_sentinel(); 262 static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; } 263 264 // Function to initialize these 265 static void initialize_known_methods(TRAPS); 266 267 static void create_preallocated_out_of_memory_errors(TRAPS); 268 269 // Reference pending list manipulation. Access is protected by 270 // Heap_lock. The getter, setter and predicate require the caller 271 // owns the lock. Swap is used by parallel non-concurrent reference 272 // processing threads, where some higher level controller owns 273 // Heap_lock, so requires the lock is locked, but not necessarily by 274 // the current thread. 275 static oop reference_pending_list(); 276 static void clear_reference_pending_list(); 277 static bool has_reference_pending_list(); 278 static oop swap_reference_pending_list(oop list); 279 280 static Array<int>* the_empty_int_array() { return _the_empty_int_array; } 281 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; } 282 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; } 283 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; } 284 static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; } 285 286 // OutOfMemoryError support. Returns an error with the required message. The returned error 287 // may or may not have a backtrace. If error has a backtrace then the stack trace is already 288 // filled in. 289 static oop out_of_memory_error_java_heap(); 290 static oop out_of_memory_error_c_heap(); 291 static oop out_of_memory_error_metaspace(); 292 static oop out_of_memory_error_class_metaspace(); 293 static oop out_of_memory_error_array_size(); 294 static oop out_of_memory_error_gc_overhead_limit(); 295 static oop out_of_memory_error_realloc_objects(); 296 297 // Throw default _out_of_memory_error_retry object as it will never propagate out of the VM 298 static oop out_of_memory_error_retry(); 299 static oop delayed_stack_overflow_error_message(); 300 301 // If it's a certain type of OOME object 302 static bool is_out_of_memory_error_metaspace(oop ex_obj); 303 static bool is_out_of_memory_error_class_metaspace(oop ex_obj); 304 305 // The particular choice of collected heap. 306 static CollectedHeap* heap() { return _collectedHeap; } 307 308 DEBUG_ONLY(static bool is_gc_active();) 309 DEBUG_ONLY(static bool is_in_heap(const void* p);) 310 DEBUG_ONLY(static bool is_in_heap_or_null(const void* p) { return p == NULL || is_in_heap(p); }) 311 312 // Reserve Java heap and determine CompressedOops mode 313 static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment); 314 315 // Global OopStorages 316 static OopStorage* vm_weak(); 317 static OopStorage* vm_global(); 318 static void oopstorage_init(); 319 320 // Testers 321 static bool is_bootstrapping() { return _bootstrapping; } 322 static bool is_module_initialized() { return _module_initialized; } 323 static bool is_fully_initialized() { return _fully_initialized; } 324 325 static bool on_page_boundary(void* addr); 326 static bool should_fill_in_stack_trace(Handle throwable); 327 static void check_alignment(uintx size, uintx alignment, const char* name); 328 329 // CDS support 330 static void serialize(SerializeClosure* f); 331 332 // Apply the closure to all klasses for basic types (classes not present in 333 // SystemDictionary). 334 static void basic_type_classes_do(KlassClosure* closure); 335 static void metaspace_pointers_do(MetaspaceClosure* it); 336 337 // Debugging 338 enum VERIFY_FLAGS { 339 Verify_Threads = 1, 340 Verify_Heap = 2, 341 Verify_SymbolTable = 4, 342 Verify_StringTable = 8, 343 Verify_CodeCache = 16, 344 Verify_SystemDictionary = 32, 345 Verify_ClassLoaderDataGraph = 64, 346 Verify_MetaspaceUtils = 128, 347 Verify_JNIHandles = 256, 348 Verify_CodeCacheOops = 512, 349 Verify_ResolvedMethodTable = 1024, 350 Verify_StringDedup = 2048, 351 Verify_All = -1 352 }; 353 static void initialize_verify_flags(); 354 static bool should_verify_subset(uint subset); 355 static void verify(VerifyOption option, const char* prefix); 356 static void verify(const char* prefix) { 357 verify(VerifyOption_Default, prefix); 358 } 359 static void verify() { 360 verify(""); 361 } 362 363 static int verify_count() { return _verify_count; } 364 static void print_on(outputStream* st); 365 static void print_heap_at_SIGBREAK(); 366 367 // Change the number of dummy objects kept reachable by the full gc dummy 368 // array; this should trigger relocation in a sliding compaction collector. 369 debug_only(static bool release_fullgc_alot_dummy();) 370 // The non-oop pattern (see compiledIC.hpp, etc) 371 static void* non_oop_word(); 372 static bool contains_non_oop_word(void* p); 373 374 // Oop verification (see MacroAssembler::verify_oop) 375 static uintptr_t verify_oop_mask() PRODUCT_RETURN0; 376 static uintptr_t verify_oop_bits() PRODUCT_RETURN0; 377 static uintptr_t verify_mark_bits() PRODUCT_RETURN0; 378 static uintptr_t verify_mark_mask() PRODUCT_RETURN0; 379 380 // Compiler support 381 static int base_vtable_size() { return _base_vtable_size; } 382 }; 383 384 #endif // SHARE_MEMORY_UNIVERSE_HPP