1/*
2 * Copyright (c) 1997, 2016, 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
49ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n, KlassHandle klass_handle, 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, klass_handle, name);
56}
57
58Klass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
59                                                int n, KlassHandle element_klass, TRAPS) {
60
61  // Eagerly allocate the direct array supertype.
62  KlassHandle super_klass = KlassHandle();
63  if (!Universe::is_bootstrapping() || SystemDictionary::Object_klass_loaded()) {
64    KlassHandle element_super (THREAD, element_klass->super());
65    if (element_super.not_null()) {
66      // The element type has a direct super.  E.g., String[] has direct super of Object[].
67      super_klass = KlassHandle(THREAD, element_super->array_klass_or_null());
68      bool supers_exist = super_klass.not_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        KlassHandle ek;
82        {
83          MutexUnlocker mu(MultiArray_lock);
84          MutexUnlocker mc(Compile_lock);   // for vtables
85          Klass* sk = element_super->array_klass(CHECK_0);
86          super_klass = KlassHandle(THREAD, sk);
87          for( int i = element_supers->length()-1; i >= 0; i-- ) {
88            KlassHandle elem_super (THREAD, element_supers->at(i));
89            elem_super->array_klass(CHECK_0);
90          }
91          // Now retry from the beginning
92          Klass* klass_oop = element_klass->array_klass(n, CHECK_0);
93          // Create a handle because the enclosing brace, when locking
94          // can cause a gc.  Better to have this function return a Handle.
95          ek = KlassHandle(THREAD, klass_oop);
96        }  // re-lock
97        return ek();
98      }
99    } else {
100      // The element type is already Object.  Object[] has direct super of Object.
101      super_klass = KlassHandle(THREAD, SystemDictionary::Object_klass());
102    }
103  }
104
105  // Create type name for klass.
106  Symbol* name = NULL;
107  if (!element_klass->is_instance_klass() ||
108      (name = InstanceKlass::cast(element_klass())->array_name()) == NULL) {
109
110    ResourceMark rm(THREAD);
111    char *name_str = element_klass->name()->as_C_string();
112    int len = element_klass->name()->utf8_length();
113    char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
114    int idx = 0;
115    new_str[idx++] = '[';
116    if (element_klass->is_instance_klass()) { // it could be an array or simple type
117      new_str[idx++] = 'L';
118    }
119    memcpy(&new_str[idx], name_str, len * sizeof(char));
120    idx += len;
121    if (element_klass->is_instance_klass()) {
122      new_str[idx++] = ';';
123    }
124    new_str[idx++] = '\0';
125    name = SymbolTable::new_permanent_symbol(new_str, CHECK_0);
126    if (element_klass->is_instance_klass()) {
127      InstanceKlass* ik = InstanceKlass::cast(element_klass());
128      ik->set_array_name(name);
129    }
130  }
131
132  // Initialize instance variables
133  ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
134
135  // Add all classes to our internal class loader list here,
136  // including classes in the bootstrap (NULL) class loader.
137  // GC walks these as strong roots.
138  loader_data->add_class(oak);
139
140  ModuleEntry* module = oak->module();
141  assert(module != NULL, "No module entry for array");
142
143  // Call complete_create_array_klass after all instance variables has been initialized.
144  ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_0);
145
146  return oak;
147}
148
149ObjArrayKlass::ObjArrayKlass(int n, KlassHandle element_klass, Symbol* name) : ArrayKlass(name) {
150  this->set_dimension(n);
151  this->set_element_klass(element_klass());
152  // decrement refcount because object arrays are not explicitly freed.  The
153  // InstanceKlass array_name() keeps the name counted while the klass is
154  // loaded.
155  name->decrement_refcount();
156
157  Klass* bk;
158  if (element_klass->is_objArray_klass()) {
159    bk = ObjArrayKlass::cast(element_klass())->bottom_klass();
160  } else {
161    bk = element_klass();
162  }
163  assert(bk != NULL && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
164  this->set_bottom_klass(bk);
165  this->set_class_loader_data(bk->class_loader_data());
166
167  this->set_layout_helper(array_layout_helper(T_OBJECT));
168  assert(this->is_array_klass(), "sanity");
169  assert(this->is_objArray_klass(), "sanity");
170}
171
172int ObjArrayKlass::oop_size(oop obj) const {
173  assert(obj->is_objArray(), "must be object array");
174  return objArrayOop(obj)->object_size();
175}
176
177objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
178  if (length >= 0) {
179    if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
180      int size = objArrayOopDesc::object_size(length);
181      KlassHandle h_k(THREAD, this);
182      return (objArrayOop)CollectedHeap::array_allocate(h_k, size, length, THREAD);
183    } else {
184      report_java_out_of_memory("Requested array size exceeds VM limit");
185      JvmtiExport::post_array_size_exhausted();
186      THROW_OOP_0(Universe::out_of_memory_error_array_size());
187    }
188  } else {
189    THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
190  }
191}
192
193static int multi_alloc_counter = 0;
194
195oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
196  int length = *sizes;
197  // Call to lower_dimension uses this pointer, so most be called before a
198  // possible GC
199  KlassHandle h_lower_dimension(THREAD, lower_dimension());
200  // If length < 0 allocate will throw an exception.
201  objArrayOop array = allocate(length, CHECK_NULL);
202  objArrayHandle h_array (THREAD, array);
203  if (rank > 1) {
204    if (length != 0) {
205      for (int index = 0; index < length; index++) {
206        ArrayKlass* ak = ArrayKlass::cast(h_lower_dimension());
207        oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
208        h_array->obj_at_put(index, sub_array);
209      }
210    } else {
211      // Since this array dimension has zero length, nothing will be
212      // allocated, however the lower dimension values must be checked
213      // for illegal values.
214      for (int i = 0; i < rank - 1; ++i) {
215        sizes += 1;
216        if (*sizes < 0) {
217          THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
218        }
219      }
220    }
221  }
222  return h_array();
223}
224
225// Either oop or narrowOop depending on UseCompressedOops.
226template <class T> void ObjArrayKlass::do_copy(arrayOop s, T* src,
227                               arrayOop d, T* dst, int length, TRAPS) {
228
229  BarrierSet* bs = Universe::heap()->barrier_set();
230  // For performance reasons, we assume we are that the write barrier we
231  // are using has optimized modes for arrays of references.  At least one
232  // of the asserts below will fail if this is not the case.
233  assert(bs->has_write_ref_array_opt(), "Barrier set must have ref array opt");
234  assert(bs->has_write_ref_array_pre_opt(), "For pre-barrier as well.");
235
236  if (s == d) {
237    // since source and destination are equal we do not need conversion checks.
238    assert(length > 0, "sanity check");
239    bs->write_ref_array_pre(dst, length);
240    Copy::conjoint_oops_atomic(src, dst, length);
241  } else {
242    // We have to make sure all elements conform to the destination array
243    Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
244    Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
245    if (stype == bound || stype->is_subtype_of(bound)) {
246      // elements are guaranteed to be subtypes, so no check necessary
247      bs->write_ref_array_pre(dst, length);
248      Copy::conjoint_oops_atomic(src, dst, length);
249    } else {
250      // slow case: need individual subtype checks
251      // note: don't use obj_at_put below because it includes a redundant store check
252      T* from = src;
253      T* end = from + length;
254      for (T* p = dst; from < end; from++, p++) {
255        // XXX this is going to be slow.
256        T element = *from;
257        // even slower now
258        bool element_is_null = oopDesc::is_null(element);
259        oop new_val = element_is_null ? oop(NULL)
260                                      : oopDesc::decode_heap_oop_not_null(element);
261        if (element_is_null ||
262            (new_val->klass())->is_subtype_of(bound)) {
263          bs->write_ref_field_pre(p, new_val);
264          *p = element;
265        } else {
266          // We must do a barrier to cover the partial copy.
267          const size_t pd = pointer_delta(p, dst, (size_t)heapOopSize);
268          // pointer delta is scaled to number of elements (length field in
269          // objArrayOop) which we assume is 32 bit.
270          assert(pd == (size_t)(int)pd, "length field overflow");
271          bs->write_ref_array((HeapWord*)dst, pd);
272          THROW(vmSymbols::java_lang_ArrayStoreException());
273          return;
274        }
275      }
276    }
277  }
278  bs->write_ref_array((HeapWord*)dst, length);
279}
280
281void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
282                               int dst_pos, int length, TRAPS) {
283  assert(s->is_objArray(), "must be obj array");
284
285  if (!d->is_objArray()) {
286    THROW(vmSymbols::java_lang_ArrayStoreException());
287  }
288
289  // Check is all offsets and lengths are non negative
290  if (src_pos < 0 || dst_pos < 0 || length < 0) {
291    THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
292  }
293  // Check if the ranges are valid
294  if  ( (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length())
295     || (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length()) ) {
296    THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
297  }
298
299  // Special case. Boundary cases must be checked first
300  // This allows the following call: copy_array(s, s.length(), d.length(), 0).
301  // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
302  // points to the right of the last element.
303  if (length==0) {
304    return;
305  }
306  if (UseCompressedOops) {
307    narrowOop* const src = objArrayOop(s)->obj_at_addr<narrowOop>(src_pos);
308    narrowOop* const dst = objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos);
309    do_copy<narrowOop>(s, src, d, dst, length, CHECK);
310  } else {
311    oop* const src = objArrayOop(s)->obj_at_addr<oop>(src_pos);
312    oop* const dst = objArrayOop(d)->obj_at_addr<oop>(dst_pos);
313    do_copy<oop> (s, src, d, dst, length, CHECK);
314  }
315}
316
317
318Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
319
320  assert(dimension() <= n, "check order of chain");
321  int dim = dimension();
322  if (dim == n) return this;
323
324  // lock-free read needs acquire semantics
325  if (higher_dimension_acquire() == NULL) {
326    if (or_null)  return NULL;
327
328    ResourceMark rm;
329    JavaThread *jt = (JavaThread *)THREAD;
330    {
331      MutexLocker mc(Compile_lock, THREAD);   // for vtables
332      // Ensure atomic creation of higher dimensions
333      MutexLocker mu(MultiArray_lock, THREAD);
334
335      // Check if another thread beat us
336      if (higher_dimension() == NULL) {
337
338        // Create multi-dim klass object and link them together
339        Klass* k =
340          ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
341        ObjArrayKlass* ak = ObjArrayKlass::cast(k);
342        ak->set_lower_dimension(this);
343        // use 'release' to pair with lock-free load
344        release_set_higher_dimension(ak);
345        assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
346      }
347    }
348  } else {
349    CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
350  }
351
352  ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
353  if (or_null) {
354    return ak->array_klass_or_null(n);
355  }
356  return ak->array_klass(n, THREAD);
357}
358
359Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
360  return array_klass_impl(or_null, dimension() +  1, THREAD);
361}
362
363bool ObjArrayKlass::can_be_primary_super_slow() const {
364  if (!bottom_klass()->can_be_primary_super())
365    // array of interfaces
366    return false;
367  else
368    return Klass::can_be_primary_super_slow();
369}
370
371GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots) {
372  // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
373  Array<Klass*>* elem_supers = element_klass()->secondary_supers();
374  int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
375  int num_secondaries = num_extra_slots + 2 + num_elem_supers;
376  if (num_secondaries == 2) {
377    // Must share this for correct bootstrapping!
378    set_secondary_supers(Universe::the_array_interfaces_array());
379    return NULL;
380  } else {
381    GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
382    secondaries->push(SystemDictionary::Cloneable_klass());
383    secondaries->push(SystemDictionary::Serializable_klass());
384    for (int i = 0; i < num_elem_supers; i++) {
385      Klass* elem_super = (Klass*) elem_supers->at(i);
386      Klass* array_super = elem_super->array_klass_or_null();
387      assert(array_super != NULL, "must already have been created");
388      secondaries->push(array_super);
389    }
390    return secondaries;
391  }
392}
393
394bool ObjArrayKlass::compute_is_subtype_of(Klass* k) {
395  if (!k->is_objArray_klass())
396    return ArrayKlass::compute_is_subtype_of(k);
397
398  ObjArrayKlass* oak = ObjArrayKlass::cast(k);
399  return element_klass()->is_subtype_of(oak->element_klass());
400}
401
402void ObjArrayKlass::initialize(TRAPS) {
403  bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
404}
405
406// JVM support
407
408jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
409  // The modifier for an objectArray is the same as its element
410  if (element_klass() == NULL) {
411    assert(Universe::is_bootstrapping(), "partial objArray only at startup");
412    return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
413  }
414  // Return the flags of the bottom element type.
415  jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
416
417  return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
418                        | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
419}
420
421ModuleEntry* ObjArrayKlass::module() const {
422  assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
423  // The array is defined in the module of its bottom class
424  return bottom_klass()->module();
425}
426
427PackageEntry* ObjArrayKlass::package() const {
428  assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
429  return bottom_klass()->package();
430}
431
432// Printing
433
434void ObjArrayKlass::print_on(outputStream* st) const {
435#ifndef PRODUCT
436  Klass::print_on(st);
437  st->print(" - instance klass: ");
438  element_klass()->print_value_on(st);
439  st->cr();
440#endif //PRODUCT
441}
442
443void ObjArrayKlass::print_value_on(outputStream* st) const {
444  assert(is_klass(), "must be klass");
445
446  element_klass()->print_value_on(st);
447  st->print("[]");
448}
449
450#ifndef PRODUCT
451
452void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
453  ArrayKlass::oop_print_on(obj, st);
454  assert(obj->is_objArray(), "must be objArray");
455  objArrayOop oa = objArrayOop(obj);
456  int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
457  for(int index = 0; index < print_len; index++) {
458    st->print(" - %3d : ", index);
459    oa->obj_at(index)->print_value_on(st);
460    st->cr();
461  }
462  int remaining = oa->length() - print_len;
463  if (remaining > 0) {
464    st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
465  }
466}
467
468#endif //PRODUCT
469
470void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
471  assert(obj->is_objArray(), "must be objArray");
472  st->print("a ");
473  element_klass()->print_value_on(st);
474  int len = objArrayOop(obj)->length();
475  st->print("[%d] ", len);
476  obj->print_address_on(st);
477}
478
479const char* ObjArrayKlass::internal_name() const {
480  return external_name();
481}
482
483
484// Verification
485
486void ObjArrayKlass::verify_on(outputStream* st) {
487  ArrayKlass::verify_on(st);
488  guarantee(element_klass()->is_klass(), "should be klass");
489  guarantee(bottom_klass()->is_klass(), "should be klass");
490  Klass* bk = bottom_klass();
491  guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
492}
493
494void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
495  ArrayKlass::oop_verify_on(obj, st);
496  guarantee(obj->is_objArray(), "must be objArray");
497  objArrayOop oa = objArrayOop(obj);
498  for(int index = 0; index < oa->length(); index++) {
499    guarantee(oa->obj_at(index)->is_oop_or_null(), "should be oop");
500  }
501}
502