1 /*
2 * Copyright (c) 1997, 2017, 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/moduleEntry.hpp"
27 #include "classfile/packageEntry.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "gc/shared/specialized_oop_closures.hpp"
33 #include "memory/iterator.inline.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/arrayKlass.inline.hpp"
38 #include "oops/instanceKlass.hpp"
39 #include "oops/klass.inline.hpp"
40 #include "oops/objArrayKlass.inline.hpp"
41 #include "oops/objArrayOop.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "runtime/handles.inline.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "utilities/copy.hpp"
47 #include "utilities/macros.hpp"
48
49 ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n, Klass* k, Symbol* name, TRAPS) {
50 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
51 "array klasses must be same size as InstanceKlass");
52
53 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
54
55 return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name);
56 }
57
58 Klass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
59 int n, Klass* element_klass, TRAPS) {
60
61 // Eagerly allocate the direct array supertype.
62 Klass* super_klass = NULL;
63 if (!Universe::is_bootstrapping() || SystemDictionary::Object_klass_loaded()) {
64 Klass* element_super = element_klass->super();
65 if (element_super != NULL) {
66 // The element type has a direct super. E.g., String[] has direct super of Object[].
67 super_klass = element_super->array_klass_or_null();
68 bool supers_exist = super_klass != NULL;
69 // Also, see if the element has secondary supertypes.
70 // We need an array type for each.
71 Array<Klass*>* element_supers = element_klass->secondary_supers();
72 for( int i = element_supers->length()-1; i >= 0; i-- ) {
73 Klass* elem_super = element_supers->at(i);
74 if (elem_super->array_klass_or_null() == NULL) {
75 supers_exist = false;
76 break;
77 }
78 }
79 if (!supers_exist) {
80 // Oops. Not allocated yet. Back out, allocate it, and retry.
81 Klass* ek = NULL;
82 {
83 MutexUnlocker mu(MultiArray_lock);
84 MutexUnlocker mc(Compile_lock); // for vtables
85 super_klass = element_super->array_klass(CHECK_0);
86 for( int i = element_supers->length()-1; i >= 0; i-- ) {
87 Klass* elem_super = element_supers->at(i);
88 elem_super->array_klass(CHECK_0);
89 }
90 // Now retry from the beginning
91 ek = element_klass->array_klass(n, CHECK_0);
92 } // re-lock
93 return ek;
94 }
95 } else {
96 // The element type is already Object. Object[] has direct super of Object.
97 super_klass = SystemDictionary::Object_klass();
98 }
99 }
100
101 // Create type name for klass.
102 Symbol* name = NULL;
103 if (!element_klass->is_instance_klass() ||
104 (name = InstanceKlass::cast(element_klass)->array_name()) == NULL) {
105
106 ResourceMark rm(THREAD);
107 char *name_str = element_klass->name()->as_C_string();
108 int len = element_klass->name()->utf8_length();
109 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
110 int idx = 0;
111 new_str[idx++] = '[';
112 if (element_klass->is_instance_klass()) { // it could be an array or simple type
113 new_str[idx++] = 'L';
114 }
115 memcpy(&new_str[idx], name_str, len * sizeof(char));
116 idx += len;
117 if (element_klass->is_instance_klass()) {
118 new_str[idx++] = ';';
119 }
120 new_str[idx++] = '\0';
121 name = SymbolTable::new_permanent_symbol(new_str, CHECK_0);
122 if (element_klass->is_instance_klass()) {
123 InstanceKlass* ik = InstanceKlass::cast(element_klass);
124 ik->set_array_name(name);
125 }
126 }
127
128 // Initialize instance variables
129 ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
130
131 // Add all classes to our internal class loader list here,
132 // including classes in the bootstrap (NULL) class loader.
133 // GC walks these as strong roots.
134 loader_data->add_class(oak);
135
136 ModuleEntry* module = oak->module();
137 assert(module != NULL, "No module entry for array");
138
139 // Call complete_create_array_klass after all instance variables has been initialized.
140 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_0);
141
142 return oak;
143 }
144
145 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name) {
146 this->set_dimension(n);
147 this->set_element_klass(element_klass);
148 // decrement refcount because object arrays are not explicitly freed. The
149 // InstanceKlass array_name() keeps the name counted while the klass is
150 // loaded.
151 name->decrement_refcount();
152
153 Klass* bk;
154 if (element_klass->is_objArray_klass()) {
155 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
156 } else {
157 bk = element_klass;
158 }
159 assert(bk != NULL && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
160 this->set_bottom_klass(bk);
161 this->set_class_loader_data(bk->class_loader_data());
162
163 this->set_layout_helper(array_layout_helper(T_OBJECT));
164 assert(this->is_array_klass(), "sanity");
165 assert(this->is_objArray_klass(), "sanity");
166 }
167
168 int ObjArrayKlass::oop_size(oop obj) const {
169 assert(obj->is_objArray(), "must be object array");
170 return objArrayOop(obj)->object_size();
171 }
172
173 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
174 if (length >= 0) {
175 if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
176 int size = objArrayOopDesc::object_size(length);
177 return (objArrayOop)CollectedHeap::array_allocate(this, size, length, THREAD);
178 } else {
179 report_java_out_of_memory("Requested array size exceeds VM limit");
180 JvmtiExport::post_array_size_exhausted();
181 THROW_OOP_0(Universe::out_of_memory_error_array_size());
182 }
183 } else {
184 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
185 }
186 }
187
188 static int multi_alloc_counter = 0;
189
190 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
191 int length = *sizes;
192 // Call to lower_dimension uses this pointer, so most be called before a
193 // possible GC
194 Klass* ld_klass = lower_dimension();
195 // If length < 0 allocate will throw an exception.
196 objArrayOop array = allocate(length, CHECK_NULL);
197 objArrayHandle h_array (THREAD, array);
198 if (rank > 1) {
199 if (length != 0) {
200 for (int index = 0; index < length; index++) {
201 ArrayKlass* ak = ArrayKlass::cast(ld_klass);
202 oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
203 h_array->obj_at_put(index, sub_array);
204 }
205 } else {
206 // Since this array dimension has zero length, nothing will be
207 // allocated, however the lower dimension values must be checked
208 // for illegal values.
209 for (int i = 0; i < rank - 1; ++i) {
210 sizes += 1;
211 if (*sizes < 0) {
212 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
213 }
214 }
215 }
216 }
217 return h_array();
218 }
219
220 // Either oop or narrowOop depending on UseCompressedOops.
221 template <class T> void ObjArrayKlass::do_copy(arrayOop s, T* src,
222 arrayOop d, T* dst, int length, TRAPS) {
223
224 BarrierSet* bs = Universe::heap()->barrier_set();
225 // For performance reasons, we assume we are that the write barrier we
226 // are using has optimized modes for arrays of references. At least one
227 // of the asserts below will fail if this is not the case.
228 assert(bs->has_write_ref_array_opt(), "Barrier set must have ref array opt");
229 assert(bs->has_write_ref_array_pre_opt(), "For pre-barrier as well.");
230
231 if (s == d) {
232 // since source and destination are equal we do not need conversion checks.
233 assert(length > 0, "sanity check");
234 bs->write_ref_array_pre(dst, length);
235 Copy::conjoint_oops_atomic(src, dst, length);
236 } else {
237 // We have to make sure all elements conform to the destination array
238 Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
239 Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
240 if (stype == bound || stype->is_subtype_of(bound)) {
241 // elements are guaranteed to be subtypes, so no check necessary
242 bs->write_ref_array_pre(dst, length);
243 Copy::conjoint_oops_atomic(src, dst, length);
244 } else {
245 // slow case: need individual subtype checks
246 // note: don't use obj_at_put below because it includes a redundant store check
247 T* from = src;
248 T* end = from + length;
249 for (T* p = dst; from < end; from++, p++) {
250 // XXX this is going to be slow.
251 T element = *from;
252 // even slower now
253 bool element_is_null = oopDesc::is_null(element);
254 oop new_val = element_is_null ? oop(NULL)
255 : oopDesc::decode_heap_oop_not_null(element);
256 if (element_is_null ||
257 (new_val->klass())->is_subtype_of(bound)) {
258 bs->write_ref_field_pre(p, new_val);
259 *p = element;
260 } else {
261 // We must do a barrier to cover the partial copy.
262 const size_t pd = pointer_delta(p, dst, (size_t)heapOopSize);
263 // pointer delta is scaled to number of elements (length field in
264 // objArrayOop) which we assume is 32 bit.
265 assert(pd == (size_t)(int)pd, "length field overflow");
266 bs->write_ref_array((HeapWord*)dst, pd);
267 THROW(vmSymbols::java_lang_ArrayStoreException());
268 return;
269 }
270 }
271 }
272 }
273 bs->write_ref_array((HeapWord*)dst, length);
274 }
275
276 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
277 int dst_pos, int length, TRAPS) {
278 assert(s->is_objArray(), "must be obj array");
279
280 if (!d->is_objArray()) {
281 THROW(vmSymbols::java_lang_ArrayStoreException());
282 }
283
284 // Check is all offsets and lengths are non negative
285 if (src_pos < 0 || dst_pos < 0 || length < 0) {
286 THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
287 }
288 // Check if the ranges are valid
289 if ( (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length())
290 || (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length()) ) {
291 THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
292 }
293
294 // Special case. Boundary cases must be checked first
295 // This allows the following call: copy_array(s, s.length(), d.length(), 0).
296 // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
297 // points to the right of the last element.
298 if (length==0) {
299 return;
300 }
301 if (UseCompressedOops) {
302 narrowOop* const src = objArrayOop(s)->obj_at_addr<narrowOop>(src_pos);
303 narrowOop* const dst = objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos);
304 do_copy<narrowOop>(s, src, d, dst, length, CHECK);
305 } else {
306 oop* const src = objArrayOop(s)->obj_at_addr<oop>(src_pos);
307 oop* const dst = objArrayOop(d)->obj_at_addr<oop>(dst_pos);
308 do_copy<oop> (s, src, d, dst, length, CHECK);
309 }
310 }
311
312
313 Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
314
315 assert(dimension() <= n, "check order of chain");
316 int dim = dimension();
317 if (dim == n) return this;
318
319 // lock-free read needs acquire semantics
320 if (higher_dimension_acquire() == NULL) {
321 if (or_null) return NULL;
322
323 ResourceMark rm;
324 JavaThread *jt = (JavaThread *)THREAD;
325 {
326 MutexLocker mc(Compile_lock, THREAD); // for vtables
327 // Ensure atomic creation of higher dimensions
328 MutexLocker mu(MultiArray_lock, THREAD);
329
330 // Check if another thread beat us
331 if (higher_dimension() == NULL) {
332
333 // Create multi-dim klass object and link them together
334 Klass* k =
335 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
336 ObjArrayKlass* ak = ObjArrayKlass::cast(k);
337 ak->set_lower_dimension(this);
338 // use 'release' to pair with lock-free load
339 release_set_higher_dimension(ak);
340 assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
341 }
342 }
343 } else {
344 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
345 }
346
347 ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
348 if (or_null) {
349 return ak->array_klass_or_null(n);
350 }
351 return ak->array_klass(n, THREAD);
352 }
353
354 Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
355 return array_klass_impl(or_null, dimension() + 1, THREAD);
356 }
357
358 bool ObjArrayKlass::can_be_primary_super_slow() const {
359 if (!bottom_klass()->can_be_primary_super())
360 // array of interfaces
361 return false;
362 else
363 return Klass::can_be_primary_super_slow();
364 }
365
366 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots) {
367 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
368 Array<Klass*>* elem_supers = element_klass()->secondary_supers();
369 int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
370 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
371 if (num_secondaries == 2) {
372 // Must share this for correct bootstrapping!
373 set_secondary_supers(Universe::the_array_interfaces_array());
374 return NULL;
375 } else {
376 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
377 secondaries->push(SystemDictionary::Cloneable_klass());
378 secondaries->push(SystemDictionary::Serializable_klass());
379 for (int i = 0; i < num_elem_supers; i++) {
380 Klass* elem_super = (Klass*) elem_supers->at(i);
381 Klass* array_super = elem_super->array_klass_or_null();
382 assert(array_super != NULL, "must already have been created");
383 secondaries->push(array_super);
384 }
385 return secondaries;
386 }
387 }
388
389 bool ObjArrayKlass::compute_is_subtype_of(Klass* k) {
390 if (!k->is_objArray_klass())
391 return ArrayKlass::compute_is_subtype_of(k);
392
393 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
394 return element_klass()->is_subtype_of(oak->element_klass());
395 }
396
397 void ObjArrayKlass::initialize(TRAPS) {
398 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
399 }
400
401 // JVM support
402
403 jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
404 // The modifier for an objectArray is the same as its element
405 if (element_klass() == NULL) {
406 assert(Universe::is_bootstrapping(), "partial objArray only at startup");
407 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
408 }
409 // Return the flags of the bottom element type.
410 jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
411
412 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
413 | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
414 }
415
416 ModuleEntry* ObjArrayKlass::module() const {
417 assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
418 // The array is defined in the module of its bottom class
419 return bottom_klass()->module();
420 }
421
422 PackageEntry* ObjArrayKlass::package() const {
423 assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
424 return bottom_klass()->package();
425 }
426
427 // Printing
428
429 void ObjArrayKlass::print_on(outputStream* st) const {
430 #ifndef PRODUCT
431 Klass::print_on(st);
432 st->print(" - instance klass: ");
433 element_klass()->print_value_on(st);
434 st->cr();
435 #endif //PRODUCT
436 }
437
438 void ObjArrayKlass::print_value_on(outputStream* st) const {
439 assert(is_klass(), "must be klass");
440
441 element_klass()->print_value_on(st);
442 st->print("[]");
443 }
444
445 #ifndef PRODUCT
446
447 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
448 ArrayKlass::oop_print_on(obj, st);
449 assert(obj->is_objArray(), "must be objArray");
450 objArrayOop oa = objArrayOop(obj);
451 int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
452 for(int index = 0; index < print_len; index++) {
453 st->print(" - %3d : ", index);
454 oa->obj_at(index)->print_value_on(st);
455 st->cr();
456 }
457 int remaining = oa->length() - print_len;
458 if (remaining > 0) {
459 st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
460 }
461 }
462
463 #endif //PRODUCT
464
465 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
466 assert(obj->is_objArray(), "must be objArray");
467 st->print("a ");
468 element_klass()->print_value_on(st);
469 int len = objArrayOop(obj)->length();
470 st->print("[%d] ", len);
471 obj->print_address_on(st);
472 }
473
474 const char* ObjArrayKlass::internal_name() const {
475 return external_name();
476 }
477
478
479 // Verification
480
481 void ObjArrayKlass::verify_on(outputStream* st) {
482 ArrayKlass::verify_on(st);
483 guarantee(element_klass()->is_klass(), "should be klass");
484 guarantee(bottom_klass()->is_klass(), "should be klass");
485 Klass* bk = bottom_klass();
486 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(), "invalid bottom klass");
487 }
488
489 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
490 ArrayKlass::oop_verify_on(obj, st);
491 guarantee(obj->is_objArray(), "must be objArray");
492 objArrayOop oa = objArrayOop(obj);
493 for(int index = 0; index < oa->length(); index++) {
494 guarantee(oa->obj_at(index)->is_oop_or_null(), "should be oop");
495 }
496 }