1 /*
   2  * Copyright (c) 1997, 2012, 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_VM_MEMORY_UNIVERSE_HPP
  26 #define SHARE_VM_MEMORY_UNIVERSE_HPP
  27 
  28 #include "runtime/handles.hpp"
  29 #include "utilities/growableArray.hpp"
  30 
  31 // Universe is a name space holding known system classes and objects in the VM.
  32 //
  33 // Loaded classes are accessible through the SystemDictionary.
  34 //
  35 // The object heap is allocated and accessed through Universe, and various allocation
  36 // support is provided. Allocation by the interpreter and compiled code is done inline
  37 // and bails out to Scavenge::invoke_and_allocate.
  38 
  39 class CollectedHeap;
  40 class DeferredObjAllocEvent;
  41 
  42 
  43 // Common parts of a methodOop cache. This cache safely interacts with
  44 // the RedefineClasses API.
  45 //
  46 class CommonMethodOopCache : public CHeapObj {
  47   // We save the klassOop and the idnum of methodOop in order to get
  48   // the current cached methodOop.
  49  private:
  50   klassOop              _klass;
  51   int                   _method_idnum;
  52 
  53  public:
  54   CommonMethodOopCache()   { _klass = NULL; _method_idnum = -1; }
  55   ~CommonMethodOopCache()  { _klass = NULL; _method_idnum = -1; }
  56 
  57   void     init(klassOop k, methodOop m, TRAPS);
  58   klassOop klass() const         { return _klass; }
  59   int      method_idnum() const  { return _method_idnum; }
  60 
  61   // GC support
  62   void     oops_do(OopClosure* f)  { f->do_oop((oop*)&_klass); }
  63 };
  64 
  65 
  66 // A helper class for caching a methodOop when the user of the cache
  67 // cares about all versions of the methodOop.
  68 //
  69 class ActiveMethodOopsCache : public CommonMethodOopCache {
  70   // This subclass adds weak references to older versions of the
  71   // methodOop and a query method for a methodOop.
  72 
  73  private:
  74   // If the cached methodOop has not been redefined, then
  75   // _prev_methods will be NULL. If all of the previous
  76   // versions of the method have been collected, then
  77   // _prev_methods can have a length of zero.
  78   GrowableArray<jweak>* _prev_methods;
  79 
  80  public:
  81   ActiveMethodOopsCache()   { _prev_methods = NULL; }
  82   ~ActiveMethodOopsCache();
  83 
  84   void add_previous_version(const methodOop method);
  85   bool is_same_method(const methodOop method) const;
  86 };
  87 
  88 
  89 // A helper class for caching a methodOop when the user of the cache
  90 // only cares about the latest version of the methodOop.
  91 //
  92 class LatestMethodOopCache : public CommonMethodOopCache {
  93   // This subclass adds a getter method for the latest methodOop.
  94 
  95  public:
  96   methodOop get_methodOop();
  97 };
  98 
  99 // For UseCompressedOops.
 100 struct NarrowOopStruct {
 101   // Base address for oop-within-java-object materialization.
 102   // NULL if using wide oops or zero based narrow oops.
 103   address _base;
 104   // Number of shift bits for encoding/decoding narrow oops.
 105   // 0 if using wide oops or zero based unscaled narrow oops,
 106   // LogMinObjAlignmentInBytes otherwise.
 107   int     _shift;
 108   // Generate code with implicit null checks for narrow oops.
 109   bool    _use_implicit_null_checks;
 110 };
 111 
 112 enum VerifyOption {
 113       VerifyOption_Default = 0,
 114 
 115       // G1
 116       VerifyOption_G1UsePrevMarking = VerifyOption_Default,
 117       VerifyOption_G1UseNextMarking = VerifyOption_G1UsePrevMarking + 1,
 118       VerifyOption_G1UseMarkWord    = VerifyOption_G1UseNextMarking + 1
 119 };
 120 
 121 class Universe: AllStatic {
 122   // Ugh.  Universe is much too friendly.
 123   friend class MarkSweep;
 124   friend class oopDesc;
 125   friend class ClassLoader;
 126   friend class Arguments;
 127   friend class SystemDictionary;
 128   friend class VMStructs;
 129   friend class CompactingPermGenGen;
 130   friend class VM_PopulateDumpSharedSpace;
 131 
 132   friend jint  universe_init();
 133   friend void  universe2_init();
 134   friend bool  universe_post_init();
 135 
 136  private:
 137   // Known classes in the VM
 138   static klassOop _boolArrayKlassObj;
 139   static klassOop _byteArrayKlassObj;
 140   static klassOop _charArrayKlassObj;
 141   static klassOop _intArrayKlassObj;
 142   static klassOop _shortArrayKlassObj;
 143   static klassOop _longArrayKlassObj;
 144   static klassOop _singleArrayKlassObj;
 145   static klassOop _doubleArrayKlassObj;
 146   static klassOop _typeArrayKlassObjs[T_VOID+1];
 147 
 148   static klassOop _objectArrayKlassObj;
 149 
 150   static klassOop _methodKlassObj;
 151   static klassOop _constMethodKlassObj;
 152   static klassOop _methodDataKlassObj;
 153   static klassOop _klassKlassObj;
 154   static klassOop _arrayKlassKlassObj;
 155   static klassOop _objArrayKlassKlassObj;
 156   static klassOop _typeArrayKlassKlassObj;
 157   static klassOop _instanceKlassKlassObj;
 158   static klassOop _constantPoolKlassObj;
 159   static klassOop _constantPoolCacheKlassObj;
 160   static klassOop _compiledICHolderKlassObj;
 161   static klassOop _systemObjArrayKlassObj;
 162 
 163   // Known objects in the VM
 164 
 165   // Primitive objects
 166   static oop _int_mirror;
 167   static oop _float_mirror;
 168   static oop _double_mirror;
 169   static oop _byte_mirror;
 170   static oop _bool_mirror;
 171   static oop _char_mirror;
 172   static oop _long_mirror;
 173   static oop _short_mirror;
 174   static oop _void_mirror;
 175 
 176   static oop          _main_thread_group;             // Reference to the main thread group object
 177   static oop          _system_thread_group;           // Reference to the system thread group object
 178 
 179   static typeArrayOop _the_empty_byte_array;          // Canonicalized byte array
 180   static typeArrayOop _the_empty_short_array;         // Canonicalized short array
 181   static typeArrayOop _the_empty_int_array;           // Canonicalized int array
 182   static objArrayOop  _the_empty_system_obj_array;    // Canonicalized system obj array
 183   static objArrayOop  _the_empty_class_klass_array;   // Canonicalized obj array of type java.lang.Class
 184   static objArrayOop  _the_array_interfaces_array;    // Canonicalized 2-array of cloneable & serializable klasses
 185   static oop          _the_null_string;               // A cache of "null" as a Java string
 186   static oop          _the_min_jint_string;          // A cache of "-2147483648" as a Java string
 187   static LatestMethodOopCache* _finalizer_register_cache; // static method for registering finalizable objects
 188   static LatestMethodOopCache* _loader_addClass_cache;    // method for registering loaded classes in class loader vector
 189   static ActiveMethodOopsCache* _reflect_invoke_cache;    // method for security checks
 190   static oop          _out_of_memory_error_java_heap; // preallocated error object (no backtrace)
 191   static oop          _out_of_memory_error_perm_gen;  // preallocated error object (no backtrace)
 192   static oop          _out_of_memory_error_array_size;// preallocated error object (no backtrace)
 193   static oop          _out_of_memory_error_gc_overhead_limit; // preallocated error object (no backtrace)
 194 
 195   static oop          _primordial_loader_cache;       // Cache a ref to the primordial app loader to avoid searching for it
 196 
 197   // array of preallocated error objects with backtrace
 198   static objArrayOop   _preallocated_out_of_memory_error_array;
 199 
 200   // number of preallocated error objects available for use
 201   static volatile jint _preallocated_out_of_memory_error_avail_count;
 202 
 203   static oop          _null_ptr_exception_instance;   // preallocated exception object
 204   static oop          _arithmetic_exception_instance; // preallocated exception object
 205   static oop          _virtual_machine_error_instance; // preallocated exception object
 206   // The object used as an exception dummy when exceptions are thrown for
 207   // the vm thread.
 208   static oop          _vm_exception;
 209 
 210   // The particular choice of collected heap.
 211   static CollectedHeap* _collectedHeap;
 212 
 213   // For UseCompressedOops.
 214   static struct NarrowOopStruct _narrow_oop;
 215 
 216   // array of dummy objects used with +FullGCAlot
 217   debug_only(static objArrayOop _fullgc_alot_dummy_array;)
 218   // index of next entry to clear
 219   debug_only(static int         _fullgc_alot_dummy_next;)
 220 
 221   // Compiler/dispatch support
 222   static int  _base_vtable_size;                      // Java vtbl size of klass Object (in words)
 223 
 224   // Initialization
 225   static bool _bootstrapping;                         // true during genesis
 226   static bool _fully_initialized;                     // true after universe_init and initialize_vtables called
 227 
 228   // the array of preallocated errors with backtraces
 229   static objArrayOop  preallocated_out_of_memory_errors()     { return _preallocated_out_of_memory_error_array; }
 230 
 231   // generate an out of memory error; if possible using an error with preallocated backtrace;
 232   // otherwise return the given default error.
 233   static oop        gen_out_of_memory_error(oop default_err);
 234 
 235   // Historic gc information
 236   static size_t _heap_capacity_at_last_gc;
 237   static size_t _heap_used_at_last_gc;
 238 
 239   static jint initialize_heap();
 240   static void initialize_basic_type_mirrors(TRAPS);
 241   static void fixup_mirrors(TRAPS);
 242 
 243   static void reinitialize_vtable_of(KlassHandle h_k, TRAPS);
 244   static void reinitialize_itables(TRAPS);
 245   static void compute_base_vtable_size();             // compute vtable size of class Object
 246 
 247   static void genesis(TRAPS);                         // Create the initial world
 248 
 249   // Mirrors for primitive classes (created eagerly)
 250   static oop check_mirror(oop m) {
 251     assert(m != NULL, "mirror not initialized");
 252     return m;
 253   }
 254 
 255   // Debugging
 256   static int _verify_count;                           // number of verifies done
 257   // True during call to verify().  Should only be set/cleared in verify().
 258   static bool _verify_in_progress;
 259 
 260   static void compute_verify_oop_data();
 261 
 262  public:
 263   // Known classes in the VM
 264   static klassOop boolArrayKlassObj()                 { return _boolArrayKlassObj;   }
 265   static klassOop byteArrayKlassObj()                 { return _byteArrayKlassObj;   }
 266   static klassOop charArrayKlassObj()                 { return _charArrayKlassObj;   }
 267   static klassOop intArrayKlassObj()                  { return _intArrayKlassObj;    }
 268   static klassOop shortArrayKlassObj()                { return _shortArrayKlassObj;  }
 269   static klassOop longArrayKlassObj()                 { return _longArrayKlassObj;   }
 270   static klassOop singleArrayKlassObj()               { return _singleArrayKlassObj; }
 271   static klassOop doubleArrayKlassObj()               { return _doubleArrayKlassObj; }
 272 
 273   static klassOop objectArrayKlassObj() {
 274     return _objectArrayKlassObj;
 275   }
 276 
 277   static klassOop typeArrayKlassObj(BasicType t) {
 278     assert((uint)t < T_VOID+1, err_msg("range check for type: %s", type2name(t)));
 279     assert(_typeArrayKlassObjs[t] != NULL, "domain check");
 280     return _typeArrayKlassObjs[t];
 281   }
 282 
 283   static klassOop methodKlassObj()                    { return _methodKlassObj;            }
 284   static klassOop constMethodKlassObj()               { return _constMethodKlassObj;         }
 285   static klassOop methodDataKlassObj()                { return _methodDataKlassObj;        }
 286   static klassOop klassKlassObj()                     { return _klassKlassObj;             }
 287   static klassOop arrayKlassKlassObj()                { return _arrayKlassKlassObj;        }
 288   static klassOop objArrayKlassKlassObj()             { return _objArrayKlassKlassObj;     }
 289   static klassOop typeArrayKlassKlassObj()            { return _typeArrayKlassKlassObj;    }
 290   static klassOop instanceKlassKlassObj()             { return _instanceKlassKlassObj;     }
 291   static klassOop constantPoolKlassObj()              { return _constantPoolKlassObj;      }
 292   static klassOop constantPoolCacheKlassObj()         { return _constantPoolCacheKlassObj; }
 293   static klassOop compiledICHolderKlassObj()          { return _compiledICHolderKlassObj;  }
 294   static klassOop systemObjArrayKlassObj()            { return _systemObjArrayKlassObj;    }
 295 
 296   // Known objects in the VM
 297   static oop int_mirror()                   { return check_mirror(_int_mirror); }
 298   static oop float_mirror()                 { return check_mirror(_float_mirror); }
 299   static oop double_mirror()                { return check_mirror(_double_mirror); }
 300   static oop byte_mirror()                  { return check_mirror(_byte_mirror); }
 301   static oop bool_mirror()                  { return check_mirror(_bool_mirror); }
 302   static oop char_mirror()                  { return check_mirror(_char_mirror); }
 303   static oop long_mirror()                  { return check_mirror(_long_mirror); }
 304   static oop short_mirror()                 { return check_mirror(_short_mirror); }
 305   static oop void_mirror()                  { return check_mirror(_void_mirror); }
 306 
 307   // table of same
 308   static oop _mirrors[T_VOID+1];
 309 
 310   static oop java_mirror(BasicType t) {
 311     assert((uint)t < T_VOID+1, "range check");
 312     return check_mirror(_mirrors[t]);
 313   }
 314   static oop      main_thread_group()                 { return _main_thread_group; }
 315   static void set_main_thread_group(oop group)        { _main_thread_group = group;}
 316 
 317   static oop      system_thread_group()               { return _system_thread_group; }
 318   static void set_system_thread_group(oop group)      { _system_thread_group = group;}
 319 
 320   static typeArrayOop the_empty_byte_array()          { return _the_empty_byte_array;          }
 321   static typeArrayOop the_empty_short_array()         { return _the_empty_short_array;         }
 322   static typeArrayOop the_empty_int_array()           { return _the_empty_int_array;           }
 323   static objArrayOop  the_empty_system_obj_array ()   { return _the_empty_system_obj_array;    }
 324   static objArrayOop  the_empty_class_klass_array ()  { return _the_empty_class_klass_array;   }
 325   static objArrayOop  the_array_interfaces_array()    { return _the_array_interfaces_array;    }
 326   static oop          the_null_string()               { return _the_null_string;               }
 327   static oop          the_min_jint_string()          { return _the_min_jint_string;          }
 328   static methodOop    finalizer_register_method()     { return _finalizer_register_cache->get_methodOop(); }
 329   static methodOop    loader_addClass_method()        { return _loader_addClass_cache->get_methodOop(); }
 330   static ActiveMethodOopsCache* reflect_invoke_cache() { return _reflect_invoke_cache; }
 331   static oop          null_ptr_exception_instance()   { return _null_ptr_exception_instance;   }
 332   static oop          arithmetic_exception_instance() { return _arithmetic_exception_instance; }
 333   static oop          virtual_machine_error_instance() { return _virtual_machine_error_instance; }
 334   static oop          vm_exception()                  { return _vm_exception; }
 335 
 336   // OutOfMemoryError support. Returns an error with the required message. The returned error
 337   // may or may not have a backtrace. If error has a backtrace then the stack trace is already
 338   // filled in.
 339   static oop out_of_memory_error_java_heap()          { return gen_out_of_memory_error(_out_of_memory_error_java_heap);  }
 340   static oop out_of_memory_error_perm_gen()           { return gen_out_of_memory_error(_out_of_memory_error_perm_gen);   }
 341   static oop out_of_memory_error_array_size()         { return gen_out_of_memory_error(_out_of_memory_error_array_size); }
 342   static oop out_of_memory_error_gc_overhead_limit()  { return gen_out_of_memory_error(_out_of_memory_error_gc_overhead_limit);  }
 343 
 344   // Accessors needed for fast allocation
 345   static klassOop* boolArrayKlassObj_addr()           { return &_boolArrayKlassObj;   }
 346   static klassOop* byteArrayKlassObj_addr()           { return &_byteArrayKlassObj;   }
 347   static klassOop* charArrayKlassObj_addr()           { return &_charArrayKlassObj;   }
 348   static klassOop* intArrayKlassObj_addr()            { return &_intArrayKlassObj;    }
 349   static klassOop* shortArrayKlassObj_addr()          { return &_shortArrayKlassObj;  }
 350   static klassOop* longArrayKlassObj_addr()           { return &_longArrayKlassObj;   }
 351   static klassOop* singleArrayKlassObj_addr()         { return &_singleArrayKlassObj; }
 352   static klassOop* doubleArrayKlassObj_addr()         { return &_doubleArrayKlassObj; }
 353   static klassOop* systemObjArrayKlassObj_addr()      { return &_systemObjArrayKlassObj; }
 354 
 355   // The particular choice of collected heap.
 356   static CollectedHeap* heap() { return _collectedHeap; }
 357 
 358   // For UseCompressedOops
 359   static address* narrow_oop_base_addr()              { return &_narrow_oop._base; }
 360   static address  narrow_oop_base()                   { return  _narrow_oop._base; }
 361   static bool  is_narrow_oop_base(void* addr)         { return (narrow_oop_base() == (address)addr); }
 362   static int      narrow_oop_shift()                  { return  _narrow_oop._shift; }
 363   static void     set_narrow_oop_base(address base)   { _narrow_oop._base  = base; }
 364   static void     set_narrow_oop_shift(int shift)     { _narrow_oop._shift = shift; }
 365   static bool     narrow_oop_use_implicit_null_checks()             { return  _narrow_oop._use_implicit_null_checks; }
 366   static void     set_narrow_oop_use_implicit_null_checks(bool use) { _narrow_oop._use_implicit_null_checks = use; }
 367   // Narrow Oop encoding mode:
 368   // 0 - Use 32-bits oops without encoding when
 369   //     NarrowOopHeapBaseMin + heap_size < 4Gb
 370   // 1 - Use zero based compressed oops with encoding when
 371   //     NarrowOopHeapBaseMin + heap_size < 32Gb
 372   // 2 - Use compressed oops with heap base + encoding.
 373   enum NARROW_OOP_MODE {
 374     UnscaledNarrowOop  = 0,
 375     ZeroBasedNarrowOop = 1,
 376     HeapBasedNarrowOop = 2
 377   };
 378   static char* preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode);
 379 
 380   // Historic gc information
 381   static size_t get_heap_capacity_at_last_gc()         { return _heap_capacity_at_last_gc; }
 382   static size_t get_heap_free_at_last_gc()             { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; }
 383   static size_t get_heap_used_at_last_gc()             { return _heap_used_at_last_gc; }
 384   static void update_heap_info_at_gc();
 385 
 386   // Testers
 387   static bool is_bootstrapping()                      { return _bootstrapping; }
 388   static bool is_fully_initialized()                  { return _fully_initialized; }
 389 
 390   // Used by JVM_LatestUserDefinedLoader to avoid stack walking to find the loader
 391   static oop get_cached_loader();
 392   static bool check_or_set_cached_loader(oop loader);        
 393 
 394   static inline bool element_type_should_be_aligned(BasicType type);
 395   static inline bool field_type_should_be_aligned(BasicType type);
 396   static bool        on_page_boundary(void* addr);
 397   static bool        should_fill_in_stack_trace(Handle throwable);
 398   static void check_alignment(uintx size, uintx alignment, const char* name);
 399 
 400   // Finalizer support.
 401   static void run_finalizers_on_exit();
 402 
 403   // Iteration
 404 
 405   // Apply "f" to the addresses of all the direct heap pointers maintained
 406   // as static fields of "Universe".
 407   static void oops_do(OopClosure* f, bool do_all = false);
 408 
 409   // Apply "f" to all klasses for basic types (classes not present in
 410   // SystemDictionary).
 411   static void basic_type_classes_do(void f(klassOop));
 412 
 413   // Apply "f" to all system klasses (classes not present in SystemDictionary).
 414   static void system_classes_do(void f(klassOop));
 415 
 416   // For sharing -- fill in a list of known vtable pointers.
 417   static void init_self_patching_vtbl_list(void** list, int count);
 418 
 419   // Debugging
 420   static bool verify_in_progress() { return _verify_in_progress; }
 421   static void verify(bool silent = false,
 422                      VerifyOption option = VerifyOption_Default );
 423   static int  verify_count()       { return _verify_count; }
 424   // The default behavior is to call print_on() on gclog_or_tty.
 425   static void print();
 426   // The extended parameter determines which method on the heap will
 427   // be called: print_on() (extended == false) or print_extended_on()
 428   // (extended == true).
 429   static void print_on(outputStream* st, bool extended = false);
 430   static void print_heap_at_SIGBREAK();
 431   static void print_heap_before_gc() { print_heap_before_gc(gclog_or_tty); }
 432   static void print_heap_after_gc()  { print_heap_after_gc(gclog_or_tty); }
 433   static void print_heap_before_gc(outputStream* st, bool ignore_extended = false);
 434   static void print_heap_after_gc(outputStream* st, bool ignore_extended = false);
 435 
 436   // Change the number of dummy objects kept reachable by the full gc dummy
 437   // array; this should trigger relocation in a sliding compaction collector.
 438   debug_only(static bool release_fullgc_alot_dummy();)
 439   // The non-oop pattern (see compiledIC.hpp, etc)
 440   static void*   non_oop_word();
 441 
 442   // Oop verification (see MacroAssembler::verify_oop)
 443   static uintptr_t verify_oop_mask()          PRODUCT_RETURN0;
 444   static uintptr_t verify_oop_bits()          PRODUCT_RETURN0;
 445   static uintptr_t verify_mark_bits()         PRODUCT_RETURN0;
 446   static uintptr_t verify_mark_mask()         PRODUCT_RETURN0;
 447   static uintptr_t verify_klass_mask()        PRODUCT_RETURN0;
 448   static uintptr_t verify_klass_bits()        PRODUCT_RETURN0;
 449 
 450   // Flushing and deoptimization
 451   static void flush_dependents_on(instanceKlassHandle dependee);
 452   static void flush_dependents_on(Handle call_site, Handle method_handle);
 453 #ifdef HOTSWAP
 454   // Flushing and deoptimization in case of evolution
 455   static void flush_evol_dependents_on(instanceKlassHandle dependee);
 456 #endif // HOTSWAP
 457   // Support for fullspeed debugging
 458   static void flush_dependents_on_method(methodHandle dependee);
 459 
 460   // Compiler support
 461   static int base_vtable_size()               { return _base_vtable_size; }
 462 };
 463 
 464 class DeferredObjAllocEvent : public CHeapObj {
 465   private:
 466     oop    _oop;
 467     size_t _bytesize;
 468     jint   _arena_id;
 469 
 470   public:
 471     DeferredObjAllocEvent(const oop o, const size_t s, const jint id) {
 472       _oop      = o;
 473       _bytesize = s;
 474       _arena_id = id;
 475     }
 476 
 477     ~DeferredObjAllocEvent() {
 478     }
 479 
 480     jint   arena_id() { return _arena_id; }
 481     size_t bytesize() { return _bytesize; }
 482     oop    get_oop()  { return _oop; }
 483 };
 484 
 485 #endif // SHARE_VM_MEMORY_UNIVERSE_HPP