Thu, 27 May 2010 18:01:56 -0700
6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb
Summary: Added new product ObjectAlignmentInBytes flag to control object alignment.
Reviewed-by: twisti, ysr, iveresov
duke@435 | 1 | /* |
jrose@1100 | 2 | * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 26 | // In order to preserve oops during garbage collection, they should be |
duke@435 | 27 | // allocated and passed around via Handles within the VM. A handle is |
duke@435 | 28 | // simply an extra indirection allocated in a thread local handle area. |
duke@435 | 29 | // |
duke@435 | 30 | // A handle is a ValueObj, so it can be passed around as a value, can |
duke@435 | 31 | // be used as a parameter w/o using &-passing, and can be returned as a |
duke@435 | 32 | // return value. |
duke@435 | 33 | // |
duke@435 | 34 | // oop parameters and return types should be Handles whenever feasible. |
duke@435 | 35 | // |
duke@435 | 36 | // Handles are declared in a straight-forward manner, e.g. |
duke@435 | 37 | // |
duke@435 | 38 | // oop obj = ...; |
duke@435 | 39 | // Handle h1(obj); // allocate new handle |
duke@435 | 40 | // Handle h2(thread, obj); // faster allocation when current thread is known |
duke@435 | 41 | // Handle h3; // declare handle only, no allocation occurs |
duke@435 | 42 | // ... |
duke@435 | 43 | // h3 = h1; // make h3 refer to same indirection as h1 |
duke@435 | 44 | // oop obj2 = h2(); // get handle value |
duke@435 | 45 | // h1->print(); // invoking operation on oop |
duke@435 | 46 | // |
duke@435 | 47 | // Handles are specialized for different oop types to provide extra type |
duke@435 | 48 | // information and avoid unnecessary casting. For each oop type xxxOop |
duke@435 | 49 | // there is a corresponding handle called xxxHandle, e.g. |
duke@435 | 50 | // |
duke@435 | 51 | // oop Handle |
duke@435 | 52 | // methodOop methodHandle |
duke@435 | 53 | // instanceOop instanceHandle |
duke@435 | 54 | // |
duke@435 | 55 | // For klassOops, it is often useful to model the Klass hierarchy in order |
duke@435 | 56 | // to get access to the klass_part without casting. For each xxxKlass there |
duke@435 | 57 | // is a corresponding handle called xxxKlassHandle, e.g. |
duke@435 | 58 | // |
duke@435 | 59 | // klassOop Klass KlassHandle |
duke@435 | 60 | // klassOop methodKlass methodKlassHandle |
duke@435 | 61 | // klassOop instanceKlass instanceKlassHandle |
duke@435 | 62 | // |
duke@435 | 63 | |
duke@435 | 64 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 65 | // Base class for all handles. Provides overloading of frequently |
duke@435 | 66 | // used operators for ease of use. |
duke@435 | 67 | |
duke@435 | 68 | class Handle VALUE_OBJ_CLASS_SPEC { |
duke@435 | 69 | private: |
duke@435 | 70 | oop* _handle; |
duke@435 | 71 | |
duke@435 | 72 | protected: |
duke@435 | 73 | oop obj() const { return _handle == NULL ? (oop)NULL : *_handle; } |
duke@435 | 74 | oop non_null_obj() const { assert(_handle != NULL, "resolving NULL handle"); return *_handle; } |
duke@435 | 75 | |
duke@435 | 76 | public: |
duke@435 | 77 | // Constructors |
duke@435 | 78 | Handle() { _handle = NULL; } |
duke@435 | 79 | Handle(oop obj); |
duke@435 | 80 | #ifndef ASSERT |
duke@435 | 81 | Handle(Thread* thread, oop obj); |
duke@435 | 82 | #else |
duke@435 | 83 | // Don't inline body with assert for current thread |
duke@435 | 84 | Handle(Thread* thread, oop obj); |
duke@435 | 85 | #endif // ASSERT |
duke@435 | 86 | |
duke@435 | 87 | // General access |
duke@435 | 88 | oop operator () () const { return obj(); } |
duke@435 | 89 | oop operator -> () const { return non_null_obj(); } |
duke@435 | 90 | bool operator == (oop o) const { return obj() == o; } |
duke@435 | 91 | bool operator == (const Handle& h) const { return obj() == h.obj(); } |
duke@435 | 92 | |
duke@435 | 93 | // Null checks |
duke@435 | 94 | bool is_null() const { return _handle == NULL; } |
duke@435 | 95 | bool not_null() const { return _handle != NULL; } |
duke@435 | 96 | |
duke@435 | 97 | // Debugging |
duke@435 | 98 | void print() { obj()->print(); } |
duke@435 | 99 | |
duke@435 | 100 | // Direct interface, use very sparingly. |
duke@435 | 101 | // Used by JavaCalls to quickly convert handles and to create handles static data structures. |
duke@435 | 102 | // Constructor takes a dummy argument to prevent unintentional type conversion in C++. |
duke@435 | 103 | Handle(oop *handle, bool dummy) { _handle = handle; } |
duke@435 | 104 | |
duke@435 | 105 | // Raw handle access. Allows easy duplication of Handles. This can be very unsafe |
duke@435 | 106 | // since duplicates is only valid as long as original handle is alive. |
duke@435 | 107 | oop* raw_value() { return _handle; } |
duke@435 | 108 | static oop raw_resolve(oop *handle) { return handle == NULL ? (oop)NULL : *handle; } |
duke@435 | 109 | }; |
duke@435 | 110 | |
duke@435 | 111 | |
duke@435 | 112 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 113 | // Base class for Handles containing klassOops. Provides overloading of frequently |
duke@435 | 114 | // used operators for ease of use and typed access to the Klass part. |
duke@435 | 115 | class KlassHandle: public Handle { |
duke@435 | 116 | protected: |
duke@435 | 117 | klassOop obj() const { return (klassOop)Handle::obj(); } |
duke@435 | 118 | klassOop non_null_obj() const { return (klassOop)Handle::non_null_obj(); } |
duke@435 | 119 | Klass* as_klass() const { return non_null_obj()->klass_part(); } |
duke@435 | 120 | |
duke@435 | 121 | public: |
duke@435 | 122 | // Constructors |
duke@435 | 123 | KlassHandle () : Handle() {} |
duke@435 | 124 | KlassHandle (oop obj) : Handle(obj) { |
duke@435 | 125 | assert(SharedSkipVerify || is_null() || obj->is_klass(), "not a klassOop"); |
duke@435 | 126 | } |
duke@435 | 127 | KlassHandle (Klass* kl) : Handle(kl ? kl->as_klassOop() : (klassOop)NULL) { |
duke@435 | 128 | assert(SharedSkipVerify || is_null() || obj()->is_klass(), "not a klassOop"); |
duke@435 | 129 | } |
duke@435 | 130 | |
duke@435 | 131 | // Faster versions passing Thread |
duke@435 | 132 | KlassHandle (Thread* thread, oop obj) : Handle(thread, obj) { |
duke@435 | 133 | assert(SharedSkipVerify || is_null() || obj->is_klass(), "not a klassOop"); |
duke@435 | 134 | } |
duke@435 | 135 | KlassHandle (Thread *thread, Klass* kl) |
duke@435 | 136 | : Handle(thread, kl ? kl->as_klassOop() : (klassOop)NULL) { |
duke@435 | 137 | assert(is_null() || obj()->is_klass(), "not a klassOop"); |
duke@435 | 138 | } |
duke@435 | 139 | |
jrose@1100 | 140 | // Direct interface, use very sparingly. |
jrose@1100 | 141 | // Used by SystemDictionaryHandles to create handles on existing WKKs. |
jrose@1100 | 142 | // The obj of such a klass handle may be null, because the handle is formed |
jrose@1100 | 143 | // during system bootstrapping. |
jrose@1100 | 144 | KlassHandle(klassOop *handle, bool dummy) : Handle((oop*)handle, dummy) { |
jrose@1100 | 145 | assert(SharedSkipVerify || is_null() || obj() == NULL || obj()->is_klass(), "not a klassOop"); |
jrose@1100 | 146 | } |
jrose@1100 | 147 | |
duke@435 | 148 | // General access |
duke@435 | 149 | klassOop operator () () const { return obj(); } |
duke@435 | 150 | Klass* operator -> () const { return as_klass(); } |
duke@435 | 151 | }; |
duke@435 | 152 | |
duke@435 | 153 | |
duke@435 | 154 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 155 | // Specific Handles for different oop types |
duke@435 | 156 | #define DEF_HANDLE(type, is_a) \ |
duke@435 | 157 | class type##Handle; \ |
duke@435 | 158 | class type##Handle: public Handle { \ |
duke@435 | 159 | protected: \ |
duke@435 | 160 | type##Oop obj() const { return (type##Oop)Handle::obj(); } \ |
duke@435 | 161 | type##Oop non_null_obj() const { return (type##Oop)Handle::non_null_obj(); } \ |
duke@435 | 162 | \ |
duke@435 | 163 | public: \ |
duke@435 | 164 | /* Constructors */ \ |
duke@435 | 165 | type##Handle () : Handle() {} \ |
duke@435 | 166 | type##Handle (type##Oop obj) : Handle((oop)obj) { \ |
duke@435 | 167 | assert(SharedSkipVerify || is_null() || ((oop)obj)->is_a(), \ |
duke@435 | 168 | "illegal type"); \ |
duke@435 | 169 | } \ |
duke@435 | 170 | type##Handle (Thread* thread, type##Oop obj) : Handle(thread, (oop)obj) { \ |
duke@435 | 171 | assert(SharedSkipVerify || is_null() || ((oop)obj)->is_a(), "illegal type"); \ |
duke@435 | 172 | } \ |
duke@435 | 173 | \ |
duke@435 | 174 | /* Special constructor, use sparingly */ \ |
duke@435 | 175 | type##Handle (type##Oop *handle, bool dummy) : Handle((oop*)handle, dummy) {} \ |
duke@435 | 176 | \ |
duke@435 | 177 | /* Operators for ease of use */ \ |
duke@435 | 178 | type##Oop operator () () const { return obj(); } \ |
duke@435 | 179 | type##Oop operator -> () const { return non_null_obj(); } \ |
duke@435 | 180 | }; |
duke@435 | 181 | |
duke@435 | 182 | |
duke@435 | 183 | DEF_HANDLE(instance , is_instance ) |
duke@435 | 184 | DEF_HANDLE(method , is_method ) |
duke@435 | 185 | DEF_HANDLE(constMethod , is_constMethod ) |
duke@435 | 186 | DEF_HANDLE(methodData , is_methodData ) |
duke@435 | 187 | DEF_HANDLE(array , is_array ) |
duke@435 | 188 | DEF_HANDLE(constantPool , is_constantPool ) |
duke@435 | 189 | DEF_HANDLE(constantPoolCache, is_constantPoolCache) |
duke@435 | 190 | DEF_HANDLE(objArray , is_objArray ) |
duke@435 | 191 | DEF_HANDLE(typeArray , is_typeArray ) |
duke@435 | 192 | DEF_HANDLE(symbol , is_symbol ) |
duke@435 | 193 | |
duke@435 | 194 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 195 | // Specific KlassHandles for different Klass types |
duke@435 | 196 | |
duke@435 | 197 | #define DEF_KLASS_HANDLE(type, is_a) \ |
duke@435 | 198 | class type##Handle : public KlassHandle { \ |
duke@435 | 199 | public: \ |
duke@435 | 200 | /* Constructors */ \ |
duke@435 | 201 | type##Handle () : KlassHandle() {} \ |
duke@435 | 202 | type##Handle (klassOop obj) : KlassHandle(obj) { \ |
duke@435 | 203 | assert(SharedSkipVerify || is_null() || obj->klass_part()->is_a(), \ |
duke@435 | 204 | "illegal type"); \ |
duke@435 | 205 | } \ |
duke@435 | 206 | type##Handle (Thread* thread, klassOop obj) : KlassHandle(thread, obj) { \ |
duke@435 | 207 | assert(SharedSkipVerify || is_null() || obj->klass_part()->is_a(), \ |
duke@435 | 208 | "illegal type"); \ |
duke@435 | 209 | } \ |
duke@435 | 210 | \ |
duke@435 | 211 | /* Access to klass part */ \ |
duke@435 | 212 | type* operator -> () const { return (type*)obj()->klass_part(); } \ |
duke@435 | 213 | \ |
duke@435 | 214 | static type##Handle cast(KlassHandle h) { return type##Handle(h()); } \ |
duke@435 | 215 | \ |
duke@435 | 216 | }; |
duke@435 | 217 | |
duke@435 | 218 | |
duke@435 | 219 | DEF_KLASS_HANDLE(instanceKlass , oop_is_instance_slow ) |
duke@435 | 220 | DEF_KLASS_HANDLE(methodKlass , oop_is_method ) |
duke@435 | 221 | DEF_KLASS_HANDLE(constMethodKlass , oop_is_constMethod ) |
duke@435 | 222 | DEF_KLASS_HANDLE(klassKlass , oop_is_klass ) |
duke@435 | 223 | DEF_KLASS_HANDLE(arrayKlassKlass , oop_is_arrayKlass ) |
duke@435 | 224 | DEF_KLASS_HANDLE(objArrayKlassKlass , oop_is_objArrayKlass ) |
duke@435 | 225 | DEF_KLASS_HANDLE(typeArrayKlassKlass , oop_is_typeArrayKlass) |
duke@435 | 226 | DEF_KLASS_HANDLE(arrayKlass , oop_is_array ) |
duke@435 | 227 | DEF_KLASS_HANDLE(typeArrayKlass , oop_is_typeArray_slow) |
duke@435 | 228 | DEF_KLASS_HANDLE(objArrayKlass , oop_is_objArray_slow ) |
duke@435 | 229 | DEF_KLASS_HANDLE(symbolKlass , oop_is_symbol ) |
duke@435 | 230 | DEF_KLASS_HANDLE(constantPoolKlass , oop_is_constantPool ) |
duke@435 | 231 | DEF_KLASS_HANDLE(constantPoolCacheKlass, oop_is_constantPool ) |
duke@435 | 232 | |
duke@435 | 233 | |
duke@435 | 234 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 235 | // Thread local handle area |
duke@435 | 236 | |
duke@435 | 237 | class HandleArea: public Arena { |
duke@435 | 238 | friend class HandleMark; |
duke@435 | 239 | friend class NoHandleMark; |
duke@435 | 240 | friend class ResetNoHandleMark; |
duke@435 | 241 | #ifdef ASSERT |
duke@435 | 242 | int _handle_mark_nesting; |
duke@435 | 243 | int _no_handle_mark_nesting; |
duke@435 | 244 | #endif |
duke@435 | 245 | HandleArea* _prev; // link to outer (older) area |
duke@435 | 246 | public: |
duke@435 | 247 | // Constructor |
duke@435 | 248 | HandleArea(HandleArea* prev) { |
duke@435 | 249 | debug_only(_handle_mark_nesting = 0); |
duke@435 | 250 | debug_only(_no_handle_mark_nesting = 0); |
duke@435 | 251 | _prev = prev; |
duke@435 | 252 | } |
duke@435 | 253 | |
duke@435 | 254 | // Handle allocation |
duke@435 | 255 | private: |
duke@435 | 256 | oop* real_allocate_handle(oop obj) { |
duke@435 | 257 | #ifdef ASSERT |
duke@435 | 258 | oop* handle = (oop*) (UseMallocOnly ? internal_malloc_4(oopSize) : Amalloc_4(oopSize)); |
duke@435 | 259 | #else |
duke@435 | 260 | oop* handle = (oop*) Amalloc_4(oopSize); |
duke@435 | 261 | #endif |
duke@435 | 262 | *handle = obj; |
duke@435 | 263 | return handle; |
duke@435 | 264 | } |
duke@435 | 265 | public: |
duke@435 | 266 | #ifdef ASSERT |
duke@435 | 267 | oop* allocate_handle(oop obj); |
duke@435 | 268 | #else |
duke@435 | 269 | oop* allocate_handle(oop obj) { return real_allocate_handle(obj); } |
duke@435 | 270 | #endif |
duke@435 | 271 | |
duke@435 | 272 | // Garbage collection support |
duke@435 | 273 | void oops_do(OopClosure* f); |
duke@435 | 274 | |
duke@435 | 275 | // Number of handles in use |
duke@435 | 276 | size_t used() const { return Arena::used() / oopSize; } |
duke@435 | 277 | |
duke@435 | 278 | debug_only(bool no_handle_mark_active() { return _no_handle_mark_nesting > 0; }) |
duke@435 | 279 | }; |
duke@435 | 280 | |
duke@435 | 281 | |
duke@435 | 282 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 283 | // Handles are allocated in a (growable) thread local handle area. Deallocation |
duke@435 | 284 | // is managed using a HandleMark. It should normally not be necessary to use |
duke@435 | 285 | // HandleMarks manually. |
duke@435 | 286 | // |
duke@435 | 287 | // A HandleMark constructor will record the current handle area top, and the |
duke@435 | 288 | // desctructor will reset the top, destroying all handles allocated in between. |
duke@435 | 289 | // The following code will therefore NOT work: |
duke@435 | 290 | // |
duke@435 | 291 | // Handle h; |
duke@435 | 292 | // { |
duke@435 | 293 | // HandleMark hm; |
duke@435 | 294 | // h = Handle(obj); |
duke@435 | 295 | // } |
duke@435 | 296 | // h()->print(); // WRONG, h destroyed by HandleMark destructor. |
duke@435 | 297 | // |
duke@435 | 298 | // If h has to be preserved, it can be converted to an oop or a local JNI handle |
duke@435 | 299 | // across the HandleMark boundary. |
duke@435 | 300 | |
duke@435 | 301 | // The base class of HandleMark should have been StackObj but we also heap allocate |
duke@435 | 302 | // a HandleMark when a thread is created. |
duke@435 | 303 | |
duke@435 | 304 | class HandleMark { |
duke@435 | 305 | private: |
duke@435 | 306 | Thread *_thread; // thread that owns this mark |
duke@435 | 307 | HandleArea *_area; // saved handle area |
duke@435 | 308 | Chunk *_chunk; // saved arena chunk |
duke@435 | 309 | char *_hwm, *_max; // saved arena info |
duke@435 | 310 | NOT_PRODUCT(size_t _size_in_bytes;) // size of handle area |
duke@435 | 311 | // Link to previous active HandleMark in thread |
duke@435 | 312 | HandleMark* _previous_handle_mark; |
duke@435 | 313 | |
duke@435 | 314 | void initialize(Thread* thread); // common code for constructors |
duke@435 | 315 | void set_previous_handle_mark(HandleMark* mark) { _previous_handle_mark = mark; } |
duke@435 | 316 | HandleMark* previous_handle_mark() const { return _previous_handle_mark; } |
duke@435 | 317 | |
duke@435 | 318 | public: |
duke@435 | 319 | HandleMark(); // see handles_inline.hpp |
duke@435 | 320 | HandleMark(Thread* thread) { initialize(thread); } |
duke@435 | 321 | ~HandleMark(); |
duke@435 | 322 | |
duke@435 | 323 | // Functions used by HandleMarkCleaner |
duke@435 | 324 | // called in the constructor of HandleMarkCleaner |
duke@435 | 325 | void push(); |
duke@435 | 326 | // called in the destructor of HandleMarkCleaner |
duke@435 | 327 | void pop_and_restore(); |
duke@435 | 328 | }; |
duke@435 | 329 | |
duke@435 | 330 | //------------------------------------------------------------------------------------------------------------------------ |
duke@435 | 331 | // A NoHandleMark stack object will verify that no handles are allocated |
duke@435 | 332 | // in its scope. Enabled in debug mode only. |
duke@435 | 333 | |
duke@435 | 334 | class NoHandleMark: public StackObj { |
duke@435 | 335 | public: |
duke@435 | 336 | #ifdef ASSERT |
duke@435 | 337 | NoHandleMark(); |
duke@435 | 338 | ~NoHandleMark(); |
duke@435 | 339 | #else |
duke@435 | 340 | NoHandleMark() {} |
duke@435 | 341 | ~NoHandleMark() {} |
duke@435 | 342 | #endif |
duke@435 | 343 | }; |
duke@435 | 344 | |
duke@435 | 345 | |
duke@435 | 346 | class ResetNoHandleMark: public StackObj { |
duke@435 | 347 | int _no_handle_mark_nesting; |
duke@435 | 348 | public: |
duke@435 | 349 | #ifdef ASSERT |
duke@435 | 350 | ResetNoHandleMark(); |
duke@435 | 351 | ~ResetNoHandleMark(); |
duke@435 | 352 | #else |
duke@435 | 353 | ResetNoHandleMark() {} |
duke@435 | 354 | ~ResetNoHandleMark() {} |
duke@435 | 355 | #endif |
duke@435 | 356 | }; |