1 /*
   2  * Copyright (c) 1999, 2010, 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 #include "incls/_precompiled.incl"
  26 #include "incls/_ciInstanceKlass.cpp.incl"
  27 
  28 // ciInstanceKlass
  29 //
  30 // This class represents a klassOop in the HotSpot virtual machine
  31 // whose Klass part in an instanceKlass.
  32 
  33 // ------------------------------------------------------------------
  34 // ciInstanceKlass::ciInstanceKlass
  35 //
  36 // Loaded instance klass.
  37 ciInstanceKlass::ciInstanceKlass(KlassHandle h_k) :
  38   ciKlass(h_k), _non_static_fields(NULL)
  39 {
  40   assert(get_Klass()->oop_is_instance(), "wrong type");
  41   instanceKlass* ik = get_instanceKlass();
  42 
  43   AccessFlags access_flags = ik->access_flags();
  44   _flags = ciFlags(access_flags);
  45   _has_finalizer = access_flags.has_finalizer();
  46   _has_subklass = ik->subklass() != NULL;
  47   _init_state = (instanceKlass::ClassState)ik->get_init_state();
  48   _nonstatic_field_size = ik->nonstatic_field_size();
  49   _has_nonstatic_fields = ik->has_nonstatic_fields();
  50   _nonstatic_fields = NULL; // initialized lazily by compute_nonstatic_fields:
  51 
  52   _nof_implementors = ik->nof_implementors();
  53   for (int i = 0; i < implementors_limit; i++) {
  54     _implementors[i] = NULL;  // we will fill these lazily
  55   }
  56 
  57   Thread *thread = Thread::current();
  58   if (ciObjectFactory::is_initialized()) {
  59     _loader = JNIHandles::make_local(thread, ik->class_loader());
  60     _protection_domain = JNIHandles::make_local(thread,
  61                                                 ik->protection_domain());
  62     _is_shared = false;
  63   } else {
  64     Handle h_loader(thread, ik->class_loader());
  65     Handle h_protection_domain(thread, ik->protection_domain());
  66     _loader = JNIHandles::make_global(h_loader);
  67     _protection_domain = JNIHandles::make_global(h_protection_domain);
  68     _is_shared = true;
  69   }
  70 
  71   // Lazy fields get filled in only upon request.
  72   _super  = NULL;
  73   _java_mirror = NULL;
  74 
  75   if (is_shared()) {
  76     if (h_k() != SystemDictionary::Object_klass()) {
  77       super();
  78     }
  79     java_mirror();
  80     //compute_nonstatic_fields();  // done outside of constructor
  81   }
  82 
  83   _field_cache = NULL;
  84 }
  85 
  86 // Version for unloaded classes:
  87 ciInstanceKlass::ciInstanceKlass(ciSymbol* name,
  88                                  jobject loader, jobject protection_domain)
  89   : ciKlass(name, ciInstanceKlassKlass::make())
  90 {
  91   assert(name->byte_at(0) != '[', "not an instance klass");
  92   _init_state = (instanceKlass::ClassState)0;
  93   _nonstatic_field_size = -1;
  94   _has_nonstatic_fields = false;
  95   _nonstatic_fields = NULL;
  96   _nof_implementors = -1;
  97   _loader = loader;
  98   _protection_domain = protection_domain;
  99   _is_shared = false;
 100   _super = NULL;
 101   _java_mirror = NULL;
 102   _field_cache = NULL;
 103 }
 104 
 105 
 106 
 107 // ------------------------------------------------------------------
 108 // ciInstanceKlass::compute_shared_is_initialized
 109 void ciInstanceKlass::compute_shared_init_state() {
 110   GUARDED_VM_ENTRY(
 111     instanceKlass* ik = get_instanceKlass();
 112     _init_state = (instanceKlass::ClassState)ik->get_init_state();
 113   )
 114 }
 115 
 116 // ------------------------------------------------------------------
 117 // ciInstanceKlass::compute_shared_has_subklass
 118 bool ciInstanceKlass::compute_shared_has_subklass() {
 119   GUARDED_VM_ENTRY(
 120     instanceKlass* ik = get_instanceKlass();
 121     _has_subklass = ik->subklass() != NULL;
 122     return _has_subklass;
 123   )
 124 }
 125 
 126 // ------------------------------------------------------------------
 127 // ciInstanceKlass::compute_shared_nof_implementors
 128 int ciInstanceKlass::compute_shared_nof_implementors() {
 129   // We requery this property, since it is a very old ciObject.
 130   GUARDED_VM_ENTRY(
 131     instanceKlass* ik = get_instanceKlass();
 132     _nof_implementors = ik->nof_implementors();
 133     return _nof_implementors;
 134   )
 135 }
 136 
 137 // ------------------------------------------------------------------
 138 // ciInstanceKlass::loader
 139 oop ciInstanceKlass::loader() {
 140   ASSERT_IN_VM;
 141   return JNIHandles::resolve(_loader);
 142 }
 143 
 144 // ------------------------------------------------------------------
 145 // ciInstanceKlass::loader_handle
 146 jobject ciInstanceKlass::loader_handle() {
 147   return _loader;
 148 }
 149 
 150 // ------------------------------------------------------------------
 151 // ciInstanceKlass::protection_domain
 152 oop ciInstanceKlass::protection_domain() {
 153   ASSERT_IN_VM;
 154   return JNIHandles::resolve(_protection_domain);
 155 }
 156 
 157 // ------------------------------------------------------------------
 158 // ciInstanceKlass::protection_domain_handle
 159 jobject ciInstanceKlass::protection_domain_handle() {
 160   return _protection_domain;
 161 }
 162 
 163 // ------------------------------------------------------------------
 164 // ciInstanceKlass::field_cache
 165 //
 166 // Get the field cache associated with this klass.
 167 ciConstantPoolCache* ciInstanceKlass::field_cache() {
 168   if (is_shared()) {
 169     return NULL;
 170   }
 171   if (_field_cache == NULL) {
 172     assert(!is_java_lang_Object(), "Object has no fields");
 173     Arena* arena = CURRENT_ENV->arena();
 174     _field_cache = new (arena) ciConstantPoolCache(arena, 5);
 175   }
 176   return _field_cache;
 177 }
 178 
 179 // ------------------------------------------------------------------
 180 // ciInstanceKlass::get_canonical_holder
 181 //
 182 ciInstanceKlass* ciInstanceKlass::get_canonical_holder(int offset) {
 183   #ifdef ASSERT
 184   if (!(offset >= 0 && offset < layout_helper())) {
 185     tty->print("*** get_canonical_holder(%d) on ", offset);
 186     this->print();
 187     tty->print_cr(" ***");
 188   };
 189   assert(offset >= 0 && offset < layout_helper(), "offset must be tame");
 190   #endif
 191 
 192   if (offset < instanceOopDesc::base_offset_in_bytes()) {
 193     // All header offsets belong properly to java/lang/Object.
 194     return CURRENT_ENV->Object_klass();
 195   }
 196 
 197   ciInstanceKlass* self = this;
 198   for (;;) {
 199     assert(self->is_loaded(), "must be loaded to have size");
 200     ciInstanceKlass* super = self->super();
 201     if (super == NULL || super->nof_nonstatic_fields() == 0 ||
 202         !super->contains_field_offset(offset)) {
 203       return self;
 204     } else {
 205       self = super;  // return super->get_canonical_holder(offset)
 206     }
 207   }
 208 }
 209 
 210 // ------------------------------------------------------------------
 211 // ciInstanceKlass::is_java_lang_Object
 212 //
 213 // Is this klass java.lang.Object?
 214 bool ciInstanceKlass::is_java_lang_Object() {
 215   return equals(CURRENT_ENV->Object_klass());
 216 }
 217 
 218 // ------------------------------------------------------------------
 219 // ciInstanceKlass::uses_default_loader
 220 bool ciInstanceKlass::uses_default_loader() {
 221   // Note:  We do not need to resolve the handle or enter the VM
 222   // in order to test null-ness.
 223   return _loader == NULL;
 224 }
 225 
 226 // ------------------------------------------------------------------
 227 // ciInstanceKlass::is_in_package
 228 //
 229 // Is this klass in the given package?
 230 bool ciInstanceKlass::is_in_package(const char* packagename, int len) {
 231   // To avoid class loader mischief, this test always rejects application classes.
 232   if (!uses_default_loader())
 233     return false;
 234   GUARDED_VM_ENTRY(
 235     return is_in_package_impl(packagename, len);
 236   )
 237 }
 238 
 239 bool ciInstanceKlass::is_in_package_impl(const char* packagename, int len) {
 240   ASSERT_IN_VM;
 241 
 242   // If packagename contains trailing '/' exclude it from the
 243   // prefix-test since we test for it explicitly.
 244   if (packagename[len - 1] == '/')
 245     len--;
 246 
 247   if (!name()->starts_with(packagename, len))
 248     return false;
 249 
 250   // Test if the class name is something like "java/lang".
 251   if ((len + 1) > name()->utf8_length())
 252     return false;
 253 
 254   // Test for trailing '/'
 255   if ((char) name()->byte_at(len) != '/')
 256     return false;
 257 
 258   // Make sure it's not actually in a subpackage:
 259   if (name()->index_of_at(len+1, "/", 1) >= 0)
 260     return false;
 261 
 262   return true;
 263 }
 264 
 265 // ------------------------------------------------------------------
 266 // ciInstanceKlass::print_impl
 267 //
 268 // Implementation of the print method.
 269 void ciInstanceKlass::print_impl(outputStream* st) {
 270   ciKlass::print_impl(st);
 271   GUARDED_VM_ENTRY(st->print(" loader=0x%x", (address)loader());)
 272   if (is_loaded()) {
 273     st->print(" loaded=true initialized=%s finalized=%s subklass=%s size=%d flags=",
 274               bool_to_str(is_initialized()),
 275               bool_to_str(has_finalizer()),
 276               bool_to_str(has_subklass()),
 277               layout_helper());
 278 
 279     _flags.print_klass_flags();
 280 
 281     if (_super) {
 282       st->print(" super=");
 283       _super->print_name();
 284     }
 285     if (_java_mirror) {
 286       st->print(" mirror=PRESENT");
 287     }
 288   } else {
 289     st->print(" loaded=false");
 290   }
 291 }
 292 
 293 // ------------------------------------------------------------------
 294 // ciInstanceKlass::super
 295 //
 296 // Get the superklass of this klass.
 297 ciInstanceKlass* ciInstanceKlass::super() {
 298   assert(is_loaded(), "must be loaded");
 299   if (_super == NULL && !is_java_lang_Object()) {
 300     GUARDED_VM_ENTRY(
 301       klassOop super_klass = get_instanceKlass()->super();
 302       _super = CURRENT_ENV->get_object(super_klass)->as_instance_klass();
 303     )
 304   }
 305   return _super;
 306 }
 307 
 308 // ------------------------------------------------------------------
 309 // ciInstanceKlass::java_mirror
 310 //
 311 // Get the instance of java.lang.Class corresponding to this klass.
 312 // Cache it on this->_java_mirror.
 313 ciInstance* ciInstanceKlass::java_mirror() {
 314   if (_java_mirror == NULL) {
 315     _java_mirror = ciKlass::java_mirror();
 316   }
 317   return _java_mirror;
 318 }
 319 
 320 // ------------------------------------------------------------------
 321 // ciInstanceKlass::unique_concrete_subklass
 322 ciInstanceKlass* ciInstanceKlass::unique_concrete_subklass() {
 323   if (!is_loaded())     return NULL; // No change if class is not loaded
 324   if (!is_abstract())   return NULL; // Only applies to abstract classes.
 325   if (!has_subklass())  return NULL; // Must have at least one subklass.
 326   VM_ENTRY_MARK;
 327   instanceKlass* ik = get_instanceKlass();
 328   Klass* up = ik->up_cast_abstract();
 329   assert(up->oop_is_instance(), "must be instanceKlass");
 330   if (ik == up) {
 331     return NULL;
 332   }
 333   return CURRENT_THREAD_ENV->get_object(up->as_klassOop())->as_instance_klass();
 334 }
 335 
 336 // ------------------------------------------------------------------
 337 // ciInstanceKlass::has_finalizable_subclass
 338 bool ciInstanceKlass::has_finalizable_subclass() {
 339   if (!is_loaded())     return true;
 340   VM_ENTRY_MARK;
 341   return Dependencies::find_finalizable_subclass(get_instanceKlass()) != NULL;
 342 }
 343 
 344 // ------------------------------------------------------------------
 345 // ciInstanceKlass::get_field_by_offset
 346 ciField* ciInstanceKlass::get_field_by_offset(int field_offset, bool is_static) {
 347   if (!is_static) {
 348     for (int i = 0, len = nof_nonstatic_fields(); i < len; i++) {
 349       ciField* field = _nonstatic_fields->at(i);
 350       int  field_off = field->offset_in_bytes();
 351       if (field_off == field_offset)
 352         return field;
 353       if (field_off > field_offset)
 354         break;
 355       // could do binary search or check bins, but probably not worth it
 356     }
 357     return NULL;
 358   }
 359   VM_ENTRY_MARK;
 360   instanceKlass* k = get_instanceKlass();
 361   fieldDescriptor fd;
 362   if (!k->find_field_from_offset(field_offset, is_static, &fd)) {
 363     return NULL;
 364   }
 365   ciField* field = new (CURRENT_THREAD_ENV->arena()) ciField(&fd);
 366   return field;
 367 }
 368 
 369 // ------------------------------------------------------------------
 370 // ciInstanceKlass::get_field_by_name
 371 ciField* ciInstanceKlass::get_field_by_name(ciSymbol* name, ciSymbol* signature, bool is_static) {
 372   VM_ENTRY_MARK;
 373   instanceKlass* k = get_instanceKlass();
 374   fieldDescriptor fd;
 375   klassOop def = k->find_field(name->get_symbolOop(), signature->get_symbolOop(), is_static, &fd);
 376   if (def == NULL) {
 377     return NULL;
 378   }
 379   ciField* field = new (CURRENT_THREAD_ENV->arena()) ciField(&fd);
 380   return field;
 381 }
 382 
 383 // ------------------------------------------------------------------
 384 // ciInstanceKlass::non_static_fields.
 385 
 386 class NonStaticFieldFiller: public FieldClosure {
 387   GrowableArray<ciField*>* _arr;
 388   ciEnv* _curEnv;
 389 public:
 390   NonStaticFieldFiller(ciEnv* curEnv, GrowableArray<ciField*>* arr) :
 391     _curEnv(curEnv), _arr(arr)
 392   {}
 393   void do_field(fieldDescriptor* fd) {
 394     ciField* field = new (_curEnv->arena()) ciField(fd);
 395     _arr->append(field);
 396   }
 397 };
 398 
 399 GrowableArray<ciField*>* ciInstanceKlass::non_static_fields() {
 400   if (_non_static_fields == NULL) {
 401     VM_ENTRY_MARK;
 402     ciEnv* curEnv = ciEnv::current();
 403     instanceKlass* ik = get_instanceKlass();
 404     int max_n_fields = ik->fields()->length()/instanceKlass::next_offset;
 405 
 406     Arena* arena = curEnv->arena();
 407     _non_static_fields =
 408       new (arena) GrowableArray<ciField*>(arena, max_n_fields, 0, NULL);
 409     NonStaticFieldFiller filler(curEnv, _non_static_fields);
 410     ik->do_nonstatic_fields(&filler);
 411   }
 412   return _non_static_fields;
 413 }
 414 
 415 static int sort_field_by_offset(ciField** a, ciField** b) {
 416   return (*a)->offset_in_bytes() - (*b)->offset_in_bytes();
 417   // (no worries about 32-bit overflow...)
 418 }
 419 
 420 // ------------------------------------------------------------------
 421 // ciInstanceKlass::compute_nonstatic_fields
 422 int ciInstanceKlass::compute_nonstatic_fields() {
 423   assert(is_loaded(), "must be loaded");
 424 
 425   if (_nonstatic_fields != NULL)
 426     return _nonstatic_fields->length();
 427 
 428   if (!has_nonstatic_fields()) {
 429     Arena* arena = CURRENT_ENV->arena();
 430     _nonstatic_fields = new (arena) GrowableArray<ciField*>(arena, 0, 0, NULL);
 431     return 0;
 432   }
 433   assert(!is_java_lang_Object(), "bootstrap OK");
 434 
 435   // Size in bytes of my fields, including inherited fields.
 436   int fsize = nonstatic_field_size() * heapOopSize;
 437 
 438   ciInstanceKlass* super = this->super();
 439   GrowableArray<ciField*>* super_fields = NULL;
 440   if (super != NULL && super->has_nonstatic_fields()) {
 441     int super_fsize  = super->nonstatic_field_size() * heapOopSize;
 442     int super_flen   = super->nof_nonstatic_fields();
 443     super_fields = super->_nonstatic_fields;
 444     assert(super_flen == 0 || super_fields != NULL, "first get nof_fields");
 445     // See if I am no larger than my super; if so, I can use his fields.
 446     if (fsize == super_fsize) {
 447       _nonstatic_fields = super_fields;
 448       return super_fields->length();
 449     }
 450   }
 451 
 452   GrowableArray<ciField*>* fields = NULL;
 453   GUARDED_VM_ENTRY({
 454       fields = compute_nonstatic_fields_impl(super_fields);
 455     });
 456 
 457   if (fields == NULL) {
 458     // This can happen if this class (java.lang.Class) has invisible fields.
 459     _nonstatic_fields = super_fields;
 460     return super_fields->length();
 461   }
 462 
 463   int flen = fields->length();
 464 
 465   // Now sort them by offset, ascending.
 466   // (In principle, they could mix with superclass fields.)
 467   fields->sort(sort_field_by_offset);
 468 #ifdef ASSERT
 469   int last_offset = instanceOopDesc::base_offset_in_bytes();
 470   for (int i = 0; i < fields->length(); i++) {
 471     ciField* field = fields->at(i);
 472     int offset = field->offset_in_bytes();
 473     int size   = (field->_type == NULL) ? heapOopSize : field->size_in_bytes();
 474     assert(last_offset <= offset, err_msg("no field overlap: %d <= %d", last_offset, offset));
 475     if (last_offset > (int)sizeof(oopDesc))
 476       assert((offset - last_offset) < BytesPerLong, "no big holes");
 477     // Note:  Two consecutive T_BYTE fields will be separated by wordSize-1
 478     // padding bytes if one of them is declared by a superclass.
 479     // This is a minor inefficiency classFileParser.cpp.
 480     last_offset = offset + size;
 481   }
 482   assert(last_offset <= (int)instanceOopDesc::base_offset_in_bytes() + fsize, "no overflow");
 483 #endif
 484 
 485   _nonstatic_fields = fields;
 486   return flen;
 487 }
 488 
 489 GrowableArray<ciField*>*
 490 ciInstanceKlass::compute_nonstatic_fields_impl(GrowableArray<ciField*>*
 491                                                super_fields) {
 492   ASSERT_IN_VM;
 493   Arena* arena = CURRENT_ENV->arena();
 494   int flen = 0;
 495   GrowableArray<ciField*>* fields = NULL;
 496   instanceKlass* k = get_instanceKlass();
 497   typeArrayOop fields_array = k->fields();
 498   for (int pass = 0; pass <= 1; pass++) {
 499     for (int i = 0, alen = fields_array->length(); i < alen; i += instanceKlass::next_offset) {
 500       fieldDescriptor fd;
 501       fd.initialize(k->as_klassOop(), i);
 502       if (fd.is_static())  continue;
 503       if (pass == 0) {
 504         flen += 1;
 505       } else {
 506         ciField* field = new (arena) ciField(&fd);
 507         fields->append(field);
 508       }
 509     }
 510 
 511     // Between passes, allocate the array:
 512     if (pass == 0) {
 513       if (flen == 0) {
 514         return NULL;  // return nothing if none are locally declared
 515       }
 516       if (super_fields != NULL) {
 517         flen += super_fields->length();
 518       }
 519       fields = new (arena) GrowableArray<ciField*>(arena, flen, 0, NULL);
 520       if (super_fields != NULL) {
 521         fields->appendAll(super_fields);
 522       }
 523     }
 524   }
 525   assert(fields->length() == flen, "sanity");
 526   return fields;
 527 }
 528 
 529 // ------------------------------------------------------------------
 530 // ciInstanceKlass::find_method
 531 //
 532 // Find a method in this klass.
 533 ciMethod* ciInstanceKlass::find_method(ciSymbol* name, ciSymbol* signature) {
 534   VM_ENTRY_MARK;
 535   instanceKlass* k = get_instanceKlass();
 536   symbolOop name_sym = name->get_symbolOop();
 537   symbolOop sig_sym= signature->get_symbolOop();
 538 
 539   methodOop m = k->find_method(name_sym, sig_sym);
 540   if (m == NULL)  return NULL;
 541 
 542   return CURRENT_THREAD_ENV->get_object(m)->as_method();
 543 }
 544 
 545 // ------------------------------------------------------------------
 546 // ciInstanceKlass::is_leaf_type
 547 bool ciInstanceKlass::is_leaf_type() {
 548   assert(is_loaded(), "must be loaded");
 549   if (is_shared()) {
 550     return is_final();  // approximately correct
 551   } else {
 552     return !_has_subklass && (_nof_implementors == 0);
 553   }
 554 }
 555 
 556 // ------------------------------------------------------------------
 557 // ciInstanceKlass::implementor
 558 //
 559 // Report an implementor of this interface.
 560 // Returns NULL if exact information is not available.
 561 // Note that there are various races here, since my copy
 562 // of _nof_implementors might be out of date with respect
 563 // to results returned by instanceKlass::implementor.
 564 // This is OK, since any dependencies we decide to assert
 565 // will be checked later under the Compile_lock.
 566 ciInstanceKlass* ciInstanceKlass::implementor(int n) {
 567   if (n > implementors_limit) {
 568     return NULL;
 569   }
 570   ciInstanceKlass* impl = _implementors[n];
 571   if (impl == NULL) {
 572     if (_nof_implementors > implementors_limit) {
 573       return NULL;
 574     }
 575     // Go into the VM to fetch the implementor.
 576     {
 577       VM_ENTRY_MARK;
 578       klassOop k = get_instanceKlass()->implementor(n);
 579       if (k != NULL) {
 580         impl = CURRENT_THREAD_ENV->get_object(k)->as_instance_klass();
 581       }
 582     }
 583     // Memoize this result.
 584     if (!is_shared()) {
 585       _implementors[n] = (impl == NULL)? this: impl;
 586     }
 587   } else if (impl == this) {
 588     impl = NULL;  // memoized null result from a VM query
 589   }
 590   return impl;
 591 }