1 /*
2 * Copyright (c) 1997, 2015, 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 "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "gc/shared/collectedHeap.inline.hpp"
30 #include "gc/shared/specialized_oop_closures.hpp"
31 #include "memory/iterator.inline.hpp"
32 #include "memory/metadataFactory.hpp"
33 #include "memory/oopFactory.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "memory/universe.inline.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/klass.inline.hpp"
38 #include "oops/objArrayKlass.inline.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/symbol.hpp"
42 #include "runtime/handles.inline.hpp"
43 #include "runtime/mutexLocker.hpp"
44 #include "runtime/orderAccess.inline.hpp"
45 #include "utilities/copy.hpp"
46 #include "utilities/macros.hpp"
47
48 ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n, KlassHandle klass_handle, Symbol* name, TRAPS) {
49 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
50 "array klasses must be same size as InstanceKlass");
51
52 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
53
54 return new (loader_data, size, THREAD) ObjArrayKlass(n, klass_handle, name);
55 }
56
57 Klass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
58 int n, KlassHandle element_klass, TRAPS) {
59
60 // Eagerly allocate the direct array supertype.
61 KlassHandle super_klass = KlassHandle();
62 if (!Universe::is_bootstrapping() || SystemDictionary::Object_klass_loaded()) {
63 KlassHandle element_super (THREAD, element_klass->super());
64 if (element_super.not_null()) {
65 // The element type has a direct super. E.g., String[] has direct super of Object[].
66 super_klass = KlassHandle(THREAD, element_super->array_klass_or_null());
67 bool supers_exist = super_klass.not_null();
68 // Also, see if the element has secondary supertypes.
69 // We need an array type for each.
70 Array<Klass*>* element_supers = element_klass->secondary_supers();
71 for( int i = element_supers->length()-1; i >= 0; i-- ) {
72 Klass* elem_super = element_supers->at(i);
73 if (elem_super->array_klass_or_null() == NULL) {
74 supers_exist = false;
75 break;
76 }
77 }
78 if (!supers_exist) {
79 // Oops. Not allocated yet. Back out, allocate it, and retry.
80 KlassHandle ek;
81 {
82 MutexUnlocker mu(MultiArray_lock);
83 MutexUnlocker mc(Compile_lock); // for vtables
84 Klass* sk = element_super->array_klass(CHECK_0);
85 super_klass = KlassHandle(THREAD, sk);
86 for( int i = element_supers->length()-1; i >= 0; i-- ) {
87 KlassHandle elem_super (THREAD, element_supers->at(i));
88 elem_super->array_klass(CHECK_0);
89 }
90 // Now retry from the beginning
91 Klass* klass_oop = element_klass->array_klass(n, CHECK_0);
92 // Create a handle because the enclosing brace, when locking
93 // can cause a gc. Better to have this function return a Handle.
94 ek = KlassHandle(THREAD, klass_oop);
95 } // re-lock
96 return ek();
97 }
98 } else {
99 // The element type is already Object. Object[] has direct super of Object.
100 super_klass = KlassHandle(THREAD, SystemDictionary::Object_klass());
101 }
102 }
103
104 // Create type name for klass.
105 Symbol* name = ArrayKlass::create_element_klass_array_name(element_klass, CHECK_NULL);
106
107 // Initialize instance variables
108 ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
109
110 // Add all classes to our internal class loader list here,
111 // including classes in the bootstrap (NULL) class loader.
112 // GC walks these as strong roots.
113 loader_data->add_class(oak);
114
115 // Call complete_create_array_klass after all instance variables has been initialized.
116 ArrayKlass::complete_create_array_klass(oak, super_klass, CHECK_0);
117
118 return oak;
119 }
120
121 ObjArrayKlass::ObjArrayKlass(int n, KlassHandle element_klass, Symbol* name) : ArrayKlass(name) {
122 this->set_dimension(n);
123 this->set_element_klass(element_klass());
124 // decrement refcount because object arrays are not explicitly freed. The
125 // InstanceKlass array_name() keeps the name counted while the klass is
126 // loaded.
127 name->decrement_refcount();
128
129 Klass* bk;
130 if (element_klass->is_objArray_klass()) {
131 bk = ObjArrayKlass::cast(element_klass())->bottom_klass();
132 } else {
133 bk = element_klass();
134 }
135 assert(bk != NULL && (bk->is_instance_klass() ||
136 bk->is_typeArray_klass() ||
137 bk->is_valueArray_klass()), "invalid bottom klass");
138 this->set_bottom_klass(bk);
139 this->set_class_loader_data(bk->class_loader_data());
140
141 this->set_layout_helper(array_layout_helper(T_OBJECT));
142 assert(this->is_array_klass(), "sanity");
143 assert(this->is_objArray_klass(), "sanity");
144 }
145
146 int ObjArrayKlass::oop_size(oop obj) const {
147 assert(obj->is_objArray(), "must be object array");
148 return objArrayOop(obj)->object_size();
149 }
150
151 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
152 if (length >= 0) {
153 if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
154 int size = objArrayOopDesc::object_size(length);
155 KlassHandle h_k(THREAD, this);
156 return (objArrayOop)CollectedHeap::array_allocate(h_k, size, length, THREAD);
157 } else {
158 report_java_out_of_memory("Requested array size exceeds VM limit");
159 JvmtiExport::post_array_size_exhausted();
160 THROW_OOP_0(Universe::out_of_memory_error_array_size());
161 }
162 } else {
163 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
164 }
165 }
166
167 static int multi_alloc_counter = 0;
168
169 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
170 int length = *sizes;
171 if (rank == 1) { // last dim may be valueArray
172 return oopFactory::new_array(element_klass(), length, CHECK_NULL);
173 }
174 guarantee(rank > 1, "Rank below 1");
175
176 // Call to lower_dimension uses this pointer, so most be called before a
177 // possible GC
178 KlassHandle h_lower_dimension(THREAD, lower_dimension());
179 // If length < 0 allocate will throw an exception.
180 objArrayOop array = allocate(length, CHECK_NULL);
181 objArrayHandle h_array (THREAD, array);
182 if (length != 0) {
183 for (int index = 0; index < length; index++) {
184 ArrayKlass* ak = ArrayKlass::cast(h_lower_dimension());
185 oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
186 h_array->obj_at_put(index, sub_array);
187 }
188 } else {
189 // Since this array dimension has zero length, nothing will be
190 // allocated, however the lower dimension values must be checked
191 // for illegal values.
192 for (int i = 0; i < rank - 1; ++i) {
193 sizes += 1;
194 if (*sizes < 0) {
195 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
196 }
197 }
198 }
199 return h_array();
200 }
201
202 // Either oop or narrowOop depending on UseCompressedOops.
203 template <class T> void ObjArrayKlass::do_copy(arrayOop s, T* src,
204 arrayOop d, T* dst, int length, TRAPS) {
205
206 BarrierSet* bs = Universe::heap()->barrier_set();
207 // For performance reasons, we assume we are that the write barrier we
208 // are using has optimized modes for arrays of references. At least one
209 // of the asserts below will fail if this is not the case.
210 assert(bs->has_write_ref_array_opt(), "Barrier set must have ref array opt");
211 assert(bs->has_write_ref_array_pre_opt(), "For pre-barrier as well.");
212
213 if (s == d) {
214 // since source and destination are equal we do not need conversion checks.
215 assert(length > 0, "sanity check");
216 bs->write_ref_array_pre(dst, length);
217 Copy::conjoint_oops_atomic(src, dst, length);
218 } else {
219 // We have to make sure all elements conform to the destination array
220 Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
221 Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
222 if (stype == bound || stype->is_subtype_of(bound)) {
223 // elements are guaranteed to be subtypes, so no check necessary
224 bs->write_ref_array_pre(dst, length);
225 Copy::conjoint_oops_atomic(src, dst, length);
226 } else {
227 // slow case: need individual subtype checks
228 // note: don't use obj_at_put below because it includes a redundant store check
229 T* from = src;
230 T* end = from + length;
231 for (T* p = dst; from < end; from++, p++) {
232 // XXX this is going to be slow.
233 T element = *from;
234 // even slower now
235 bool element_is_null = oopDesc::is_null(element);
236 oop new_val = element_is_null ? oop(NULL)
237 : oopDesc::decode_heap_oop_not_null(element);
238 if (element_is_null ||
239 (new_val->klass())->is_subtype_of(bound)) {
240 bs->write_ref_field_pre(p, new_val);
241 *p = element;
242 } else {
243 // We must do a barrier to cover the partial copy.
244 const size_t pd = pointer_delta(p, dst, (size_t)heapOopSize);
245 // pointer delta is scaled to number of elements (length field in
246 // objArrayOop) which we assume is 32 bit.
247 assert(pd == (size_t)(int)pd, "length field overflow");
248 bs->write_ref_array((HeapWord*)dst, pd);
249 THROW(vmSymbols::java_lang_ArrayStoreException());
250 return;
251 }
252 }
253 }
254 }
255 bs->write_ref_array((HeapWord*)dst, length);
256 }
257
258 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
259 int dst_pos, int length, TRAPS) {
260 assert(s->is_objArray(), "must be obj array");
261
262 if (!d->is_objArray()) {
263 THROW(vmSymbols::java_lang_ArrayStoreException());
264 }
265
266 // Check is all offsets and lengths are non negative
267 if (src_pos < 0 || dst_pos < 0 || length < 0) {
268 THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
269 }
270 // Check if the ranges are valid
271 if ( (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length())
272 || (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length()) ) {
273 THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
274 }
275
276 // Special case. Boundary cases must be checked first
277 // This allows the following call: copy_array(s, s.length(), d.length(), 0).
278 // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
279 // points to the right of the last element.
280 if (length==0) {
281 return;
282 }
283 if (UseCompressedOops) {
284 narrowOop* const src = objArrayOop(s)->obj_at_addr<narrowOop>(src_pos);
285 narrowOop* const dst = objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos);
286 do_copy<narrowOop>(s, src, d, dst, length, CHECK);
287 } else {
288 oop* const src = objArrayOop(s)->obj_at_addr<oop>(src_pos);
289 oop* const dst = objArrayOop(d)->obj_at_addr<oop>(dst_pos);
290 do_copy<oop> (s, src, d, dst, length, CHECK);
291 }
292 }
293
294 Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
295
296 assert(dimension() <= n, "check order of chain");
297 int dim = dimension();
298 if (dim == n) return this;
299
300 if (higher_dimension() == NULL) {
301 if (or_null) return NULL;
302
303 ResourceMark rm;
304 JavaThread *jt = (JavaThread *)THREAD;
305 {
306 MutexLocker mc(Compile_lock, THREAD); // for vtables
307 // Ensure atomic creation of higher dimensions
308 MutexLocker mu(MultiArray_lock, THREAD);
309
310 // Check if another thread beat us
311 if (higher_dimension() == NULL) {
312
313 // Create multi-dim klass object and link them together
314 Klass* k =
315 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
316 ObjArrayKlass* ak = ObjArrayKlass::cast(k);
317 ak->set_lower_dimension(this);
318 OrderAccess::storestore();
319 set_higher_dimension(ak);
320 assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
321 }
322 }
323 } else {
324 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
325 }
326
327 ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
328 if (or_null) {
329 return ak->array_klass_or_null(n);
330 }
331 return ak->array_klass(n, THREAD);
332 }
333
334 Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
335 return array_klass_impl(or_null, dimension() + 1, THREAD);
336 }
337
338 bool ObjArrayKlass::can_be_primary_super_slow() const {
339 if (!bottom_klass()->can_be_primary_super())
340 // array of interfaces
341 return false;
342 else
343 return Klass::can_be_primary_super_slow();
344 }
345
346 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots) {
347 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
348 Array<Klass*>* elem_supers = element_klass()->secondary_supers();
349 int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
350 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
351 if (num_secondaries == 2) {
352 // Must share this for correct bootstrapping!
353 if (EnableExtraSuper) {
354 set_secondary_supers(Universe::the_empty_klass_array());
355 }
356 else {
357 set_secondary_supers(Universe::the_array_interfaces_array());
358 }
359 return NULL;
360 } else {
361 int len = num_elem_supers;
362 if (!EnableExtraSuper) {
363 len += 2;
364 }
365 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(len);
366 if (!EnableExtraSuper) {
367 secondaries->push(SystemDictionary::Cloneable_klass());
368 secondaries->push(SystemDictionary::Serializable_klass());
369 }
370 for (int i = 0; i < num_elem_supers; i++) {
371 Klass* elem_super = (Klass*) elem_supers->at(i);
372 Klass* array_super = elem_super->array_klass_or_null();
373 assert(array_super != NULL, "must already have been created");
374 secondaries->push(array_super);
375 }
376 return secondaries;
377 }
378 }
379
380 bool ObjArrayKlass::compute_is_subtype_of(Klass* k) {
381 if (!k->is_objArray_klass())
382 return ArrayKlass::compute_is_subtype_of(k);
383
384 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
385 return element_klass()->is_subtype_of(oak->element_klass());
386 }
387
388 void ObjArrayKlass::initialize(TRAPS) {
389 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
390 }
391
392 // JVM support
393
394 jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
395 // The modifier for an objectArray is the same as its element
396 if (element_klass() == NULL) {
397 assert(Universe::is_bootstrapping(), "partial objArray only at startup");
398 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
399 }
400 // Return the flags of the bottom element type.
401 jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
402
403 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
404 | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
405 }
406
407
408 // Printing
409
410 void ObjArrayKlass::print_on(outputStream* st) const {
411 #ifndef PRODUCT
412 Klass::print_on(st);
413 st->print(" - element klass: ");
414 element_klass()->print_value_on(st);
415 st->cr();
416 #endif //PRODUCT
417 }
418
419 void ObjArrayKlass::print_value_on(outputStream* st) const {
420 assert(is_klass(), "must be klass");
421
422 element_klass()->print_value_on(st);
423 st->print("[]");
424 }
425
426 #ifndef PRODUCT
427
428 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
429 ArrayKlass::oop_print_on(obj, st);
430 assert(obj->is_objArray(), "must be objArray");
431 objArrayOop oa = objArrayOop(obj);
432 int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
433 for(int index = 0; index < print_len; index++) {
434 st->print(" - %3d : ", index);
435 oa->obj_at(index)->print_value_on(st);
436 st->cr();
437 }
438 int remaining = oa->length() - print_len;
439 if (remaining > 0) {
440 st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
441 }
442 }
443
444 #endif //PRODUCT
445
446 static int max_objArray_print_length = 4;
447
448 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
449 assert(obj->is_objArray(), "must be objArray");
450 st->print("a ");
451 element_klass()->print_value_on(st);
452 int len = objArrayOop(obj)->length();
453 st->print("[%d] ", len);
454 obj->print_address_on(st);
455 if (NOT_PRODUCT(PrintOopAddress ||) PrintMiscellaneous && (WizardMode || Verbose)) {
456 st->print("{");
457 for (int i = 0; i < len; i++) {
458 if (i > max_objArray_print_length) {
459 st->print("..."); break;
460 }
461 st->print(" " INTPTR_FORMAT, (intptr_t)(void*)objArrayOop(obj)->obj_at(i));
462 }
463 st->print(" }");
464 }
465 }
466
467 const char* ObjArrayKlass::internal_name() const {
468 return external_name();
469 }
470
471
472 // Verification
473
474 void ObjArrayKlass::verify_on(outputStream* st) {
475 ArrayKlass::verify_on(st);
476 guarantee(element_klass()->is_klass(), "should be klass");
477 guarantee(bottom_klass()->is_klass(), "should be klass");
478 Klass* bk = bottom_klass();
479 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(), "invalid bottom klass");
480 }
481
482 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
483 ArrayKlass::oop_verify_on(obj, st);
484 guarantee(obj->is_objArray(), "must be objArray");
485 objArrayOop oa = objArrayOop(obj);
486 for(int index = 0; index < oa->length(); index++) {
487 guarantee(oa->obj_at(index)->is_oop_or_null(), "should be oop");
488 }
489 }