1 /*
  2  * Copyright (c) 2016, 2021, 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 "gc/shared/barrierSet.hpp"
 27 #include "gc/shared/c2/barrierSetC2.hpp"
 28 #include "gc/shared/c2/cardTableBarrierSetC2.hpp"
 29 #include "gc/shared/gc_globals.hpp"
 30 #include "opto/arraycopynode.hpp"
 31 #include "opto/graphKit.hpp"
 32 #include "runtime/sharedRuntime.hpp"
 33 #include "utilities/macros.hpp"
 34 #include "utilities/powerOfTwo.hpp"
 35 
 36 ArrayCopyNode::ArrayCopyNode(Compile* C, bool alloc_tightly_coupled, bool has_negative_length_guard)
 37   : CallNode(arraycopy_type(), NULL, TypePtr::BOTTOM),
 38     _kind(None),
 39     _alloc_tightly_coupled(alloc_tightly_coupled),
 40     _has_negative_length_guard(has_negative_length_guard),
 41     _arguments_validated(false),
 42     _src_type(TypeOopPtr::BOTTOM),
 43     _dest_type(TypeOopPtr::BOTTOM) {
 44   init_class_id(Class_ArrayCopy);
 45   init_flags(Flag_is_macro);
 46   C->add_macro_node(this);
 47 }
 48 
 49 uint ArrayCopyNode::size_of() const { return sizeof(*this); }
 50 
 51 ArrayCopyNode* ArrayCopyNode::make(GraphKit* kit, bool may_throw,
 52                                    Node* src, Node* src_offset,
 53                                    Node* dest, Node* dest_offset,
 54                                    Node* length,
 55                                    bool alloc_tightly_coupled,
 56                                    bool has_negative_length_guard,
 57                                    Node* src_klass, Node* dest_klass,
 58                                    Node* src_length, Node* dest_length) {
 59 
 60   ArrayCopyNode* ac = new ArrayCopyNode(kit->C, alloc_tightly_coupled, has_negative_length_guard);
 61   kit->set_predefined_input_for_runtime_call(ac);
 62 
 63   ac->init_req(ArrayCopyNode::Src, src);
 64   ac->init_req(ArrayCopyNode::SrcPos, src_offset);
 65   ac->init_req(ArrayCopyNode::Dest, dest);
 66   ac->init_req(ArrayCopyNode::DestPos, dest_offset);
 67   ac->init_req(ArrayCopyNode::Length, length);
 68   ac->init_req(ArrayCopyNode::SrcLen, src_length);
 69   ac->init_req(ArrayCopyNode::DestLen, dest_length);
 70   ac->init_req(ArrayCopyNode::SrcKlass, src_klass);
 71   ac->init_req(ArrayCopyNode::DestKlass, dest_klass);
 72 
 73   if (may_throw) {
 74     ac->set_req(TypeFunc::I_O , kit->i_o());
 75     kit->add_safepoint_edges(ac, false);
 76   }
 77 
 78   return ac;
 79 }
 80 
 81 void ArrayCopyNode::connect_outputs(GraphKit* kit, bool deoptimize_on_exception) {
 82   kit->set_all_memory_call(this, true);
 83   kit->set_control(kit->gvn().transform(new ProjNode(this,TypeFunc::Control)));
 84   kit->set_i_o(kit->gvn().transform(new ProjNode(this, TypeFunc::I_O)));
 85   kit->make_slow_call_ex(this, kit->env()->Throwable_klass(), true, deoptimize_on_exception);
 86   kit->set_all_memory_call(this);
 87 }
 88 
 89 #ifndef PRODUCT
 90 const char* ArrayCopyNode::_kind_names[] = {"arraycopy", "arraycopy, validated arguments", "clone", "oop array clone", "CopyOf", "CopyOfRange"};
 91 
 92 void ArrayCopyNode::dump_spec(outputStream *st) const {
 93   CallNode::dump_spec(st);
 94   st->print(" (%s%s)", _kind_names[_kind], _alloc_tightly_coupled ? ", tightly coupled allocation" : "");
 95 }
 96 
 97 void ArrayCopyNode::dump_compact_spec(outputStream* st) const {
 98   st->print("%s%s", _kind_names[_kind], _alloc_tightly_coupled ? ",tight" : "");
 99 }
100 #endif
101 
102 intptr_t ArrayCopyNode::get_length_if_constant(PhaseGVN *phase) const {
103   // check that length is constant
104   Node* length = in(ArrayCopyNode::Length);
105   const Type* length_type = phase->type(length);
106 
107   if (length_type == Type::TOP) {
108     return -1;
109   }
110 
111   assert(is_clonebasic() || is_arraycopy() || is_copyof() || is_copyofrange(), "unexpected array copy type");
112 
113   return is_clonebasic() ? length->find_intptr_t_con(-1) : length->find_int_con(-1);
114 }
115 
116 int ArrayCopyNode::get_count(PhaseGVN *phase) const {
117   Node* src = in(ArrayCopyNode::Src);
118   const Type* src_type = phase->type(src);
119 
120   if (is_clonebasic()) {
121     if (src_type->isa_instptr()) {
122       const TypeInstPtr* inst_src = src_type->is_instptr();
123       ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
124       // ciInstanceKlass::nof_nonstatic_fields() doesn't take injected
125       // fields into account. They are rare anyway so easier to simply
126       // skip instances with injected fields.
127       if ((!inst_src->klass_is_exact() && (ik->is_interface() || ik->has_subklass())) || ik->has_injected_fields()) {
128         return -1;
129       }
130       int nb_fields = ik->nof_nonstatic_fields();
131       return nb_fields;
132     } else {
133       const TypeAryPtr* ary_src = src_type->isa_aryptr();
134       assert (ary_src != NULL, "not an array or instance?");
135       // clone passes a length as a rounded number of longs. If we're
136       // cloning an array we'll do it element by element. If the
137       // length input to ArrayCopyNode is constant, length of input
138       // array must be too.
139 
140       assert((get_length_if_constant(phase) == -1) != ary_src->size()->is_con() ||
141              phase->is_IterGVN() || phase->C->inlining_incrementally() || StressReflectiveCode, "inconsistent");
142 
143       if (ary_src->size()->is_con()) {
144         return ary_src->size()->get_con();
145       }
146       return -1;
147     }
148   }
149 
150   return get_length_if_constant(phase);
151 }
152 
153 Node* ArrayCopyNode::load(BarrierSetC2* bs, PhaseGVN *phase, Node*& ctl, MergeMemNode* mem, Node* adr, const TypePtr* adr_type, const Type *type, BasicType bt) {
154   DecoratorSet decorators = C2_READ_ACCESS | C2_CONTROL_DEPENDENT_LOAD | IN_HEAP | C2_ARRAY_COPY;
155   C2AccessValuePtr addr(adr, adr_type);
156   C2OptAccess access(*phase, ctl, mem, decorators, bt, adr->in(AddPNode::Base), addr);
157   Node* res = bs->load_at(access, type);
158   ctl = access.ctl();
159   return res;
160 }
161 
162 void ArrayCopyNode::store(BarrierSetC2* bs, PhaseGVN *phase, Node*& ctl, MergeMemNode* mem, Node* adr, const TypePtr* adr_type, Node* val, const Type *type, BasicType bt) {
163   DecoratorSet decorators = C2_WRITE_ACCESS | IN_HEAP | C2_ARRAY_COPY;
164   if (is_alloc_tightly_coupled()) {
165     decorators |= C2_TIGHTLY_COUPLED_ALLOC;
166   }
167   C2AccessValuePtr addr(adr, adr_type);
168   C2AccessValue value(val, type);
169   C2OptAccess access(*phase, ctl, mem, decorators, bt, adr->in(AddPNode::Base), addr);
170   bs->store_at(access, value);
171   ctl = access.ctl();
172 }
173 
174 
175 Node* ArrayCopyNode::try_clone_instance(PhaseGVN *phase, bool can_reshape, int count) {
176   if (!is_clonebasic()) {
177     return NULL;
178   }
179 
180   Node* base_src = in(ArrayCopyNode::Src);
181   Node* base_dest = in(ArrayCopyNode::Dest);
182   Node* ctl = in(TypeFunc::Control);
183   Node* in_mem = in(TypeFunc::Memory);
184 
185   const Type* src_type = phase->type(base_src);
186   const TypeInstPtr* inst_src = src_type->isa_instptr();
187   if (inst_src == NULL) {
188     return NULL;
189   }
190 
191   MergeMemNode* mem = phase->transform(MergeMemNode::make(in_mem))->as_MergeMem();
192   PhaseIterGVN* igvn = phase->is_IterGVN();
193   if (igvn != NULL) {
194     igvn->_worklist.push(mem);
195   }
196 
197   if (!inst_src->klass_is_exact()) {
198     ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
199     assert(!ik->is_interface(), "inconsistent klass hierarchy");
200     if (ik->has_subklass()) {
201       // Concurrent class loading.
202       // Fail fast and return NodeSentinel to indicate that the transform failed.
203       return NodeSentinel;
204     } else {
205       phase->C->dependencies()->assert_leaf_type(ik);
206     }
207   }
208 
209   ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
210   assert(ik->nof_nonstatic_fields() <= ArrayCopyLoadStoreMaxElem, "too many fields");
211 
212   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
213   for (int i = 0; i < count; i++) {
214     ciField* field = ik->nonstatic_field_at(i);
215     const TypePtr* adr_type = phase->C->alias_type(field)->adr_type();
216     Node* off = phase->MakeConX(field->offset());
217     Node* next_src = phase->transform(new AddPNode(base_src,base_src,off));
218     Node* next_dest = phase->transform(new AddPNode(base_dest,base_dest,off));
219     BasicType bt = field->layout_type();
220 
221     const Type *type;
222     if (bt == T_OBJECT) {
223       if (!field->type()->is_loaded()) {
224         type = TypeInstPtr::BOTTOM;
225       } else {
226         ciType* field_klass = field->type();
227         type = TypeOopPtr::make_from_klass(field_klass->as_klass());
228       }
229     } else {
230       type = Type::get_const_basic_type(bt);
231     }
232 
233     Node* v = load(bs, phase, ctl, mem, next_src, adr_type, type, bt);
234     store(bs, phase, ctl, mem, next_dest, adr_type, v, type, bt);
235   }
236 
237   if (!finish_transform(phase, can_reshape, ctl, mem)) {
238     // Return NodeSentinel to indicate that the transform failed
239     return NodeSentinel;
240   }
241 
242   return mem;
243 }
244 
245 bool ArrayCopyNode::prepare_array_copy(PhaseGVN *phase, bool can_reshape,
246                                        Node*& adr_src,
247                                        Node*& base_src,
248                                        Node*& adr_dest,
249                                        Node*& base_dest,
250                                        BasicType& copy_type,
251                                        const Type*& value_type,
252                                        bool& disjoint_bases) {
253   base_src = in(ArrayCopyNode::Src);
254   base_dest = in(ArrayCopyNode::Dest);
255   const Type* src_type = phase->type(base_src);
256   const TypeAryPtr* ary_src = src_type->isa_aryptr();
257 
258   Node* src_offset = in(ArrayCopyNode::SrcPos);
259   Node* dest_offset = in(ArrayCopyNode::DestPos);
260 
261   if (is_arraycopy() || is_copyofrange() || is_copyof()) {
262     const Type* dest_type = phase->type(base_dest);
263     const TypeAryPtr* ary_dest = dest_type->isa_aryptr();
264 
265     // newly allocated object is guaranteed to not overlap with source object
266     disjoint_bases = is_alloc_tightly_coupled();
267 
268     if (ary_src  == NULL || ary_src->klass()  == NULL ||
269         ary_dest == NULL || ary_dest->klass() == NULL) {
270       // We don't know if arguments are arrays
271       return false;
272     }
273 
274     BasicType src_elem  = ary_src->klass()->as_array_klass()->element_type()->basic_type();
275     BasicType dest_elem = ary_dest->klass()->as_array_klass()->element_type()->basic_type();
276     if (is_reference_type(src_elem))   src_elem  = T_OBJECT;
277     if (is_reference_type(dest_elem))  dest_elem = T_OBJECT;
278 
279     if (src_elem != dest_elem || dest_elem == T_VOID) {
280       // We don't know if arguments are arrays of the same type
281       return false;
282     }
283 
284     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
285     if (bs->array_copy_requires_gc_barriers(is_alloc_tightly_coupled(), dest_elem, false, false, BarrierSetC2::Optimization)) {
286       // It's an object array copy but we can't emit the card marking
287       // that is needed
288       return false;
289     }
290 
291     value_type = ary_src->elem();
292 
293     uint shift  = exact_log2(type2aelembytes(dest_elem));
294     uint header = arrayOopDesc::base_offset_in_bytes(dest_elem);
295 
296     src_offset = Compile::conv_I2X_index(phase, src_offset, ary_src->size());
297     dest_offset = Compile::conv_I2X_index(phase, dest_offset, ary_dest->size());
298     if (src_offset->is_top() || dest_offset->is_top()) {
299       // Offset is out of bounds (the ArrayCopyNode will be removed)
300       return false;
301     }
302 
303     Node* src_scale  = phase->transform(new LShiftXNode(src_offset, phase->intcon(shift)));
304     Node* dest_scale = phase->transform(new LShiftXNode(dest_offset, phase->intcon(shift)));
305 
306     adr_src          = phase->transform(new AddPNode(base_src, base_src, src_scale));
307     adr_dest         = phase->transform(new AddPNode(base_dest, base_dest, dest_scale));
308 
309     adr_src          = phase->transform(new AddPNode(base_src, adr_src, phase->MakeConX(header)));
310     adr_dest         = phase->transform(new AddPNode(base_dest, adr_dest, phase->MakeConX(header)));
311 
312     copy_type = dest_elem;
313   } else {
314     assert(ary_src != NULL, "should be a clone");
315     assert(is_clonebasic(), "should be");
316 
317     disjoint_bases = true;
318 
319     adr_src  = phase->transform(new AddPNode(base_src, base_src, src_offset));
320     adr_dest = phase->transform(new AddPNode(base_dest, base_dest, dest_offset));
321 
322     BasicType elem = ary_src->klass()->as_array_klass()->element_type()->basic_type();
323     if (is_reference_type(elem)) {
324       elem = T_OBJECT;
325     }
326 
327     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
328     if (bs->array_copy_requires_gc_barriers(true, elem, true, is_clone_inst(), BarrierSetC2::Optimization)) {
329       return false;
330     }
331 
332     // The address is offseted to an aligned address where a raw copy would start.
333     // If the clone copy is decomposed into load-stores - the address is adjusted to
334     // point at where the array starts.
335     const Type* toff = phase->type(src_offset);
336     int offset = toff->isa_long() ? (int) toff->is_long()->get_con() : (int) toff->is_int()->get_con();
337     int diff = arrayOopDesc::base_offset_in_bytes(elem) - offset;
338     assert(diff >= 0, "clone should not start after 1st array element");
339     if (diff > 0) {
340       adr_src = phase->transform(new AddPNode(base_src, adr_src, phase->MakeConX(diff)));
341       adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, phase->MakeConX(diff)));
342     }
343     copy_type = elem;
344     value_type = ary_src->elem();
345   }
346   return true;
347 }
348 
349 const TypePtr* ArrayCopyNode::get_address_type(PhaseGVN* phase, const TypePtr* atp, Node* n) {
350   if (atp == TypeOopPtr::BOTTOM) {
351     atp = phase->type(n)->isa_ptr();
352   }
353   // adjust atp to be the correct array element address type
354   return atp->add_offset(Type::OffsetBot);
355 }
356 
357 void ArrayCopyNode::array_copy_test_overlap(PhaseGVN *phase, bool can_reshape, bool disjoint_bases, int count, Node*& forward_ctl, Node*& backward_ctl) {
358   Node* ctl = in(TypeFunc::Control);
359   if (!disjoint_bases && count > 1) {
360     Node* src_offset = in(ArrayCopyNode::SrcPos);
361     Node* dest_offset = in(ArrayCopyNode::DestPos);
362     assert(src_offset != NULL && dest_offset != NULL, "should be");
363     Node* cmp = phase->transform(new CmpINode(src_offset, dest_offset));
364     Node *bol = phase->transform(new BoolNode(cmp, BoolTest::lt));
365     IfNode *iff = new IfNode(ctl, bol, PROB_FAIR, COUNT_UNKNOWN);
366 
367     phase->transform(iff);
368 
369     forward_ctl = phase->transform(new IfFalseNode(iff));
370     backward_ctl = phase->transform(new IfTrueNode(iff));
371   } else {
372     forward_ctl = ctl;
373   }
374 }
375 
376 Node* ArrayCopyNode::array_copy_forward(PhaseGVN *phase,
377                                         bool can_reshape,
378                                         Node*& forward_ctl,
379                                         Node* mem,
380                                         const TypePtr* atp_src,
381                                         const TypePtr* atp_dest,
382                                         Node* adr_src,
383                                         Node* base_src,
384                                         Node* adr_dest,
385                                         Node* base_dest,
386                                         BasicType copy_type,
387                                         const Type* value_type,
388                                         int count) {
389   if (!forward_ctl->is_top()) {
390     // copy forward
391     MergeMemNode* mm = MergeMemNode::make(mem);
392 
393     if (count > 0) {
394       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
395       Node* v = load(bs, phase, forward_ctl, mm, adr_src, atp_src, value_type, copy_type);
396       store(bs, phase, forward_ctl, mm, adr_dest, atp_dest, v, value_type, copy_type);
397       for (int i = 1; i < count; i++) {
398         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
399         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
400         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
401         v = load(bs, phase, forward_ctl, mm, next_src, atp_src, value_type, copy_type);
402         store(bs, phase, forward_ctl, mm, next_dest, atp_dest, v, value_type, copy_type);
403       }
404     } else if (can_reshape) {
405       PhaseIterGVN* igvn = phase->is_IterGVN();
406       igvn->_worklist.push(adr_src);
407       igvn->_worklist.push(adr_dest);
408     }
409     return mm;
410   }
411   return phase->C->top();
412 }
413 
414 Node* ArrayCopyNode::array_copy_backward(PhaseGVN *phase,
415                                          bool can_reshape,
416                                          Node*& backward_ctl,
417                                          Node* mem,
418                                          const TypePtr* atp_src,
419                                          const TypePtr* atp_dest,
420                                          Node* adr_src,
421                                          Node* base_src,
422                                          Node* adr_dest,
423                                          Node* base_dest,
424                                          BasicType copy_type,
425                                          const Type* value_type,
426                                          int count) {
427   if (!backward_ctl->is_top()) {
428     // copy backward
429     MergeMemNode* mm = MergeMemNode::make(mem);
430 
431     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
432     assert(copy_type != T_OBJECT || !bs->array_copy_requires_gc_barriers(false, T_OBJECT, false, false, BarrierSetC2::Optimization), "only tightly coupled allocations for object arrays");
433 
434     if (count > 0) {
435       for (int i = count-1; i >= 1; i--) {
436         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
437         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
438         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
439         Node* v = load(bs, phase, backward_ctl, mm, next_src, atp_src, value_type, copy_type);
440         store(bs, phase, backward_ctl, mm, next_dest, atp_dest, v, value_type, copy_type);
441       }
442       Node* v = load(bs, phase, backward_ctl, mm, adr_src, atp_src, value_type, copy_type);
443       store(bs, phase, backward_ctl, mm, adr_dest, atp_dest, v, value_type, copy_type);
444     } else if (can_reshape) {
445       PhaseIterGVN* igvn = phase->is_IterGVN();
446       igvn->_worklist.push(adr_src);
447       igvn->_worklist.push(adr_dest);
448     }
449     return phase->transform(mm);
450   }
451   return phase->C->top();
452 }
453 
454 bool ArrayCopyNode::finish_transform(PhaseGVN *phase, bool can_reshape,
455                                      Node* ctl, Node *mem) {
456   if (can_reshape) {
457     PhaseIterGVN* igvn = phase->is_IterGVN();
458     igvn->set_delay_transform(false);
459     if (is_clonebasic()) {
460       Node* out_mem = proj_out(TypeFunc::Memory);
461 
462       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
463       if (out_mem->outcnt() != 1 || !out_mem->raw_out(0)->is_MergeMem() ||
464           out_mem->raw_out(0)->outcnt() != 1 || !out_mem->raw_out(0)->raw_out(0)->is_MemBar()) {
465         assert(bs->array_copy_requires_gc_barriers(true, T_OBJECT, true, is_clone_inst(), BarrierSetC2::Optimization), "can only happen with card marking");
466         return false;
467       }
468 
469       igvn->replace_node(out_mem->raw_out(0), mem);
470 
471       Node* out_ctl = proj_out(TypeFunc::Control);
472       igvn->replace_node(out_ctl, ctl);
473     } else {
474       // replace fallthrough projections of the ArrayCopyNode by the
475       // new memory, control and the input IO.
476       CallProjections callprojs;
477       extract_projections(&callprojs, true, false);
478 
479       if (callprojs.fallthrough_ioproj != NULL) {
480         igvn->replace_node(callprojs.fallthrough_ioproj, in(TypeFunc::I_O));
481       }
482       if (callprojs.fallthrough_memproj != NULL) {
483         igvn->replace_node(callprojs.fallthrough_memproj, mem);
484       }
485       if (callprojs.fallthrough_catchproj != NULL) {
486         igvn->replace_node(callprojs.fallthrough_catchproj, ctl);
487       }
488 
489       // The ArrayCopyNode is not disconnected. It still has the
490       // projections for the exception case. Replace current
491       // ArrayCopyNode with a dummy new one with a top() control so
492       // that this part of the graph stays consistent but is
493       // eventually removed.
494 
495       set_req(0, phase->C->top());
496       remove_dead_region(phase, can_reshape);
497     }
498   } else {
499     if (in(TypeFunc::Control) != ctl) {
500       // we can't return new memory and control from Ideal at parse time
501       assert(!is_clonebasic() || UseShenandoahGC, "added control for clone?");
502       phase->record_for_igvn(this);
503       return false;
504     }
505   }
506   return true;
507 }
508 
509 
510 Node *ArrayCopyNode::Ideal(PhaseGVN *phase, bool can_reshape) {
511   if (remove_dead_region(phase, can_reshape))  return this;
512 
513   if (StressArrayCopyMacroNode && !can_reshape) {
514     phase->record_for_igvn(this);
515     return NULL;
516   }
517 
518   // See if it's a small array copy and we can inline it as
519   // loads/stores
520   // Here we can only do:
521   // - arraycopy if all arguments were validated before and we don't
522   // need card marking
523   // - clone for which we don't need to do card marking
524 
525   if (!is_clonebasic() && !is_arraycopy_validated() &&
526       !is_copyofrange_validated() && !is_copyof_validated()) {
527     return NULL;
528   }
529 
530   assert(in(TypeFunc::Control) != NULL &&
531          in(TypeFunc::Memory) != NULL &&
532          in(ArrayCopyNode::Src) != NULL &&
533          in(ArrayCopyNode::Dest) != NULL &&
534          in(ArrayCopyNode::Length) != NULL &&
535          in(ArrayCopyNode::SrcPos) != NULL &&
536          in(ArrayCopyNode::DestPos) != NULL, "broken inputs");
537 
538   if (in(TypeFunc::Control)->is_top() ||
539       in(TypeFunc::Memory)->is_top() ||
540       phase->type(in(ArrayCopyNode::Src)) == Type::TOP ||
541       phase->type(in(ArrayCopyNode::Dest)) == Type::TOP ||
542       (in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::SrcPos)->is_top()) ||
543       (in(ArrayCopyNode::DestPos) != NULL && in(ArrayCopyNode::DestPos)->is_top())) {
544     return NULL;
545   }
546 
547   int count = get_count(phase);
548 
549   if (count < 0 || count > ArrayCopyLoadStoreMaxElem) {
550     return NULL;
551   }
552 
553   Node* mem = try_clone_instance(phase, can_reshape, count);
554   if (mem != NULL) {
555     return (mem == NodeSentinel) ? NULL : mem;
556   }
557 
558   Node* adr_src = NULL;
559   Node* base_src = NULL;
560   Node* adr_dest = NULL;
561   Node* base_dest = NULL;
562   BasicType copy_type = T_ILLEGAL;
563   const Type* value_type = NULL;
564   bool disjoint_bases = false;
565 
566   if (!prepare_array_copy(phase, can_reshape,
567                           adr_src, base_src, adr_dest, base_dest,
568                           copy_type, value_type, disjoint_bases)) {
569     return NULL;
570   }
571 
572   Node* src = in(ArrayCopyNode::Src);
573   Node* dest = in(ArrayCopyNode::Dest);
574   const TypePtr* atp_src = get_address_type(phase, _src_type, src);
575   const TypePtr* atp_dest = get_address_type(phase, _dest_type, dest);
576   Node* in_mem = in(TypeFunc::Memory);
577 
578   if (can_reshape) {
579     assert(!phase->is_IterGVN()->delay_transform(), "cannot delay transforms");
580     phase->is_IterGVN()->set_delay_transform(true);
581   }
582 
583   Node* backward_ctl = phase->C->top();
584   Node* forward_ctl = phase->C->top();
585   array_copy_test_overlap(phase, can_reshape, disjoint_bases, count, forward_ctl, backward_ctl);
586 
587   Node* forward_mem = array_copy_forward(phase, can_reshape, forward_ctl,
588                                          in_mem,
589                                          atp_src, atp_dest,
590                                          adr_src, base_src, adr_dest, base_dest,
591                                          copy_type, value_type, count);
592 
593   Node* backward_mem = array_copy_backward(phase, can_reshape, backward_ctl,
594                                            in_mem,
595                                            atp_src, atp_dest,
596                                            adr_src, base_src, adr_dest, base_dest,
597                                            copy_type, value_type, count);
598 
599   Node* ctl = NULL;
600   if (!forward_ctl->is_top() && !backward_ctl->is_top()) {
601     ctl = new RegionNode(3);
602     ctl->init_req(1, forward_ctl);
603     ctl->init_req(2, backward_ctl);
604     ctl = phase->transform(ctl);
605     MergeMemNode* forward_mm = forward_mem->as_MergeMem();
606     MergeMemNode* backward_mm = backward_mem->as_MergeMem();
607     for (MergeMemStream mms(forward_mm, backward_mm); mms.next_non_empty2(); ) {
608       if (mms.memory() != mms.memory2()) {
609         Node* phi = new PhiNode(ctl, Type::MEMORY, phase->C->get_adr_type(mms.alias_idx()));
610         phi->init_req(1, mms.memory());
611         phi->init_req(2, mms.memory2());
612         phi = phase->transform(phi);
613         mms.set_memory(phi);
614       }
615     }
616     mem = forward_mem;
617   } else if (!forward_ctl->is_top()) {
618     ctl = forward_ctl;
619     mem = forward_mem;
620   } else {
621     assert(!backward_ctl->is_top(), "no copy?");
622     ctl = backward_ctl;
623     mem = backward_mem;
624   }
625 
626   if (can_reshape) {
627     assert(phase->is_IterGVN()->delay_transform(), "should be delaying transforms");
628     phase->is_IterGVN()->set_delay_transform(false);
629   }
630 
631   if (!finish_transform(phase, can_reshape, ctl, mem)) {
632     return NULL;
633   }
634 
635   return mem;
636 }
637 
638 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
639   Node* dest = in(ArrayCopyNode::Dest);
640   if (dest->is_top()) {
641     return false;
642   }
643   const TypeOopPtr* dest_t = phase->type(dest)->is_oopptr();
644   assert(!dest_t->is_known_instance() || _dest_type->is_known_instance(), "result of EA not recorded");
645   assert(in(ArrayCopyNode::Src)->is_top() || !phase->type(in(ArrayCopyNode::Src))->is_oopptr()->is_known_instance() ||
646          _src_type->is_known_instance(), "result of EA not recorded");
647 
648   if (_dest_type != TypeOopPtr::BOTTOM || t_oop->is_known_instance()) {
649     assert(_dest_type == TypeOopPtr::BOTTOM || _dest_type->is_known_instance(), "result of EA is known instance");
650     return t_oop->instance_id() == _dest_type->instance_id();
651   }
652 
653   return CallNode::may_modify_arraycopy_helper(dest_t, t_oop, phase);
654 }
655 
656 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr *t_oop, Node* n, PhaseTransform *phase, CallNode*& call) {
657   if (n != NULL &&
658       n->is_Call() &&
659       n->as_Call()->may_modify(t_oop, phase) &&
660       (n->as_Call()->is_ArrayCopy() || n->as_Call()->is_call_to_arraycopystub())) {
661     call = n->as_Call();
662     return true;
663   }
664   return false;
665 }
666 
667 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, MemBarNode* mb, PhaseTransform *phase, ArrayCopyNode*& ac) {
668 
669   Node* c = mb->in(0);
670 
671   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
672   // step over g1 gc barrier if we're at e.g. a clone with ReduceInitialCardMarks off
673   c = bs->step_over_gc_barrier(c);
674 
675   CallNode* call = NULL;
676   guarantee(c != NULL, "step_over_gc_barrier failed, there must be something to step to.");
677   if (c->is_Region()) {
678     for (uint i = 1; i < c->req(); i++) {
679       if (c->in(i) != NULL) {
680         Node* n = c->in(i)->in(0);
681         if (may_modify_helper(t_oop, n, phase, call)) {
682           ac = call->isa_ArrayCopy();
683           assert(c == mb->in(0), "only for clone");
684           return true;
685         }
686       }
687     }
688   } else if (may_modify_helper(t_oop, c->in(0), phase, call)) {
689     ac = call->isa_ArrayCopy();
690 #ifdef ASSERT
691     bool use_ReduceInitialCardMarks = BarrierSet::barrier_set()->is_a(BarrierSet::CardTableBarrierSet) &&
692       static_cast<CardTableBarrierSetC2*>(bs)->use_ReduceInitialCardMarks();
693     assert(c == mb->in(0) || (ac != NULL && ac->is_clonebasic() && !use_ReduceInitialCardMarks), "only for clone");
694 #endif
695     return true;
696   } else if (mb->trailing_partial_array_copy()) {
697     return true;
698   }
699 
700   return false;
701 }
702 
703 // Does this array copy modify offsets between offset_lo and offset_hi
704 // in the destination array
705 // if must_modify is false, return true if the copy could write
706 // between offset_lo and offset_hi
707 // if must_modify is true, return true if the copy is guaranteed to
708 // write between offset_lo and offset_hi
709 bool ArrayCopyNode::modifies(intptr_t offset_lo, intptr_t offset_hi, PhaseTransform* phase, bool must_modify) const {
710   assert(_kind == ArrayCopy || _kind == CopyOf || _kind == CopyOfRange, "only for real array copies");
711 
712   Node* dest = in(Dest);
713   Node* dest_pos = in(DestPos);
714   Node* len = in(Length);
715 
716   const TypeInt *dest_pos_t = phase->type(dest_pos)->isa_int();
717   const TypeInt *len_t = phase->type(len)->isa_int();
718   const TypeAryPtr* ary_t = phase->type(dest)->isa_aryptr();
719 
720   if (dest_pos_t == NULL || len_t == NULL || ary_t == NULL) {
721     return !must_modify;
722   }
723 
724   BasicType ary_elem = ary_t->klass()->as_array_klass()->element_type()->basic_type();
725   uint header = arrayOopDesc::base_offset_in_bytes(ary_elem);
726   uint elemsize = type2aelembytes(ary_elem);
727 
728   jlong dest_pos_plus_len_lo = (((jlong)dest_pos_t->_lo) + len_t->_lo) * elemsize + header;
729   jlong dest_pos_plus_len_hi = (((jlong)dest_pos_t->_hi) + len_t->_hi) * elemsize + header;
730   jlong dest_pos_lo = ((jlong)dest_pos_t->_lo) * elemsize + header;
731   jlong dest_pos_hi = ((jlong)dest_pos_t->_hi) * elemsize + header;
732 
733   if (must_modify) {
734     if (offset_lo >= dest_pos_hi && offset_hi < dest_pos_plus_len_lo) {
735       return true;
736     }
737   } else {
738     if (offset_hi >= dest_pos_lo && offset_lo < dest_pos_plus_len_hi) {
739       return true;
740     }
741   }
742   return false;
743 }
744 
745 // As an optimization, choose optimum vector size for copy length known at compile time.
746 int ArrayCopyNode::get_partial_inline_vector_lane_count(BasicType type, int const_len) {
747   int lane_count = ArrayOperationPartialInlineSize/type2aelembytes(type);
748   if (const_len > 0) {
749     int size_in_bytes = const_len * type2aelembytes(type);
750     if (size_in_bytes <= 16)
751       lane_count = 16/type2aelembytes(type);
752     else if (size_in_bytes > 16 && size_in_bytes <= 32)
753       lane_count = 32/type2aelembytes(type);
754   }
755   return lane_count;
756 }