1 /*
   2  * Copyright (c) 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 "opto/arraycopynode.hpp"
  27 #include "opto/graphKit.hpp"
  28 #include "runtime/sharedRuntime.hpp"
  29 
  30 ArrayCopyNode::ArrayCopyNode(Compile* C, bool alloc_tightly_coupled, bool has_negative_length_guard)
  31   : CallNode(arraycopy_type(), NULL, TypeRawPtr::BOTTOM),
  32     _alloc_tightly_coupled(alloc_tightly_coupled),
  33     _has_negative_length_guard(has_negative_length_guard),
  34     _kind(None),
  35     _arguments_validated(false),
  36     _src_type(TypeOopPtr::BOTTOM),
  37     _dest_type(TypeOopPtr::BOTTOM) {
  38   init_class_id(Class_ArrayCopy);
  39   init_flags(Flag_is_macro);
  40   C->add_macro_node(this);
  41 }
  42 
  43 uint ArrayCopyNode::size_of() const { return sizeof(*this); }
  44 
  45 ArrayCopyNode* ArrayCopyNode::make(GraphKit* kit, bool may_throw,
  46                                    Node* src, Node* src_offset,
  47                                    Node* dest, Node* dest_offset,
  48                                    Node* length,
  49                                    bool alloc_tightly_coupled,
  50                                    bool has_negative_length_guard,
  51                                    Node* src_klass, Node* dest_klass,
  52                                    Node* src_length, Node* dest_length) {
  53 
  54   ArrayCopyNode* ac = new ArrayCopyNode(kit->C, alloc_tightly_coupled, has_negative_length_guard);
  55   Node* prev_mem = kit->set_predefined_input_for_runtime_call(ac);
  56 
  57   ac->init_req(ArrayCopyNode::Src, src);
  58   ac->init_req(ArrayCopyNode::SrcPos, src_offset);
  59   ac->init_req(ArrayCopyNode::Dest, dest);
  60   ac->init_req(ArrayCopyNode::DestPos, dest_offset);
  61   ac->init_req(ArrayCopyNode::Length, length);
  62   ac->init_req(ArrayCopyNode::SrcLen, src_length);
  63   ac->init_req(ArrayCopyNode::DestLen, dest_length);
  64   ac->init_req(ArrayCopyNode::SrcKlass, src_klass);
  65   ac->init_req(ArrayCopyNode::DestKlass, dest_klass);
  66 
  67   if (may_throw) {
  68     ac->set_req(TypeFunc::I_O , kit->i_o());
  69     kit->add_safepoint_edges(ac, false);
  70   }
  71 
  72   return ac;
  73 }
  74 
  75 void ArrayCopyNode::connect_outputs(GraphKit* kit) {
  76   kit->set_all_memory_call(this, true);
  77   kit->set_control(kit->gvn().transform(new ProjNode(this,TypeFunc::Control)));
  78   kit->set_i_o(kit->gvn().transform(new ProjNode(this, TypeFunc::I_O)));
  79   kit->make_slow_call_ex(this, kit->env()->Throwable_klass(), true);
  80   kit->set_all_memory_call(this);
  81 }
  82 
  83 #ifndef PRODUCT
  84 const char* ArrayCopyNode::_kind_names[] = {"arraycopy", "arraycopy, validated arguments", "clone", "oop array clone", "CopyOf", "CopyOfRange"};
  85 
  86 void ArrayCopyNode::dump_spec(outputStream *st) const {
  87   CallNode::dump_spec(st);
  88   st->print(" (%s%s)", _kind_names[_kind], _alloc_tightly_coupled ? ", tightly coupled allocation" : "");
  89 }
  90 
  91 void ArrayCopyNode::dump_compact_spec(outputStream* st) const {
  92   st->print("%s%s", _kind_names[_kind], _alloc_tightly_coupled ? ",tight" : "");
  93 }
  94 #endif
  95 
  96 intptr_t ArrayCopyNode::get_length_if_constant(PhaseGVN *phase) const {
  97   // check that length is constant
  98   Node* length = in(ArrayCopyNode::Length);
  99   const Type* length_type = phase->type(length);
 100 
 101   if (length_type == Type::TOP) {
 102     return -1;
 103   }
 104 
 105   assert(is_clonebasic() || is_arraycopy() || is_copyof() || is_copyofrange(), "unexpected array copy type");
 106 
 107   return is_clonebasic() ? length->find_intptr_t_con(-1) : length->find_int_con(-1);
 108 }
 109 
 110 int ArrayCopyNode::get_count(PhaseGVN *phase) const {
 111   Node* src = in(ArrayCopyNode::Src);
 112   const Type* src_type = phase->type(src);
 113 
 114   if (is_clonebasic()) {
 115     if (src_type->isa_instptr()) {
 116       const TypeInstPtr* inst_src = src_type->is_instptr();
 117       ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 118       // ciInstanceKlass::nof_nonstatic_fields() doesn't take injected
 119       // fields into account. They are rare anyway so easier to simply
 120       // skip instances with injected fields.
 121       if ((!inst_src->klass_is_exact() && (ik->is_interface() || ik->has_subklass())) || ik->has_injected_fields()) {
 122         return -1;
 123       }
 124       int nb_fields = ik->nof_nonstatic_fields();
 125       return nb_fields;
 126     } else {
 127       const TypeAryPtr* ary_src = src_type->isa_aryptr();
 128       assert (ary_src != NULL, "not an array or instance?");
 129       // clone passes a length as a rounded number of longs. If we're
 130       // cloning an array we'll do it element by element. If the
 131       // length input to ArrayCopyNode is constant, length of input
 132       // array must be too.
 133 
 134       assert((get_length_if_constant(phase) == -1) == !ary_src->size()->is_con() ||
 135              phase->is_IterGVN(), "inconsistent");
 136 
 137       if (ary_src->size()->is_con()) {
 138         return ary_src->size()->get_con();
 139       }
 140       return -1;
 141     }
 142   }
 143 
 144   return get_length_if_constant(phase);
 145 }
 146 
 147 Node* ArrayCopyNode::try_clone_instance(PhaseGVN *phase, bool can_reshape, int count) {
 148   if (!is_clonebasic()) {
 149     return NULL;
 150   }
 151 
 152   Node* src = in(ArrayCopyNode::Src);
 153   Node* dest = in(ArrayCopyNode::Dest);
 154   Node* ctl = in(TypeFunc::Control);
 155   Node* in_mem = in(TypeFunc::Memory);
 156 
 157   const Type* src_type = phase->type(src);
 158 
 159   assert(src->is_AddP(), "should be base + off");
 160   assert(dest->is_AddP(), "should be base + off");
 161   Node* base_src = src->in(AddPNode::Base);
 162   Node* base_dest = dest->in(AddPNode::Base);
 163 
 164   MergeMemNode* mem = MergeMemNode::make(in_mem);
 165 
 166   const TypeInstPtr* inst_src = src_type->isa_instptr();
 167 
 168   if (inst_src == NULL) {
 169     return NULL;
 170   }
 171 
 172   if (!inst_src->klass_is_exact()) {
 173     ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 174     assert(!ik->is_interface() && !ik->has_subklass(), "inconsistent klass hierarchy");
 175     phase->C->dependencies()->assert_leaf_type(ik);
 176   }
 177 
 178   ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 179   assert(ik->nof_nonstatic_fields() <= ArrayCopyLoadStoreMaxElem, "too many fields");
 180 
 181   for (int i = 0; i < count; i++) {
 182     ciField* field = ik->nonstatic_field_at(i);
 183     int fieldidx = phase->C->alias_type(field)->index();
 184     const TypePtr* adr_type = phase->C->alias_type(field)->adr_type();
 185     Node* off = phase->MakeConX(field->offset());
 186     Node* next_src = phase->transform(new AddPNode(base_src,base_src,off));
 187     Node* next_dest = phase->transform(new AddPNode(base_dest,base_dest,off));
 188     BasicType bt = field->layout_type();
 189 
 190     const Type *type;
 191     if (bt == T_OBJECT) {
 192       if (!field->type()->is_loaded()) {
 193         type = TypeInstPtr::BOTTOM;
 194       } else {
 195         ciType* field_klass = field->type();
 196         type = TypeOopPtr::make_from_klass(field_klass->as_klass());
 197       }
 198     } else {
 199       type = Type::get_const_basic_type(bt);
 200     }
 201 
 202     Node* v = LoadNode::make(*phase, ctl, mem->memory_at(fieldidx), next_src, adr_type, type, bt, MemNode::unordered);
 203     v = phase->transform(v);
 204     Node* s = StoreNode::make(*phase, ctl, mem->memory_at(fieldidx), next_dest, adr_type, v, bt, MemNode::unordered);
 205     s = phase->transform(s);
 206     mem->set_memory_at(fieldidx, s);
 207   }
 208 
 209   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 210     // Return NodeSentinel to indicate that the transform failed
 211     return NodeSentinel;
 212   }
 213 
 214   return mem;
 215 }
 216 
 217 bool ArrayCopyNode::prepare_array_copy(PhaseGVN *phase, bool can_reshape,
 218                                        Node*& adr_src,
 219                                        Node*& base_src,
 220                                        Node*& adr_dest,
 221                                        Node*& base_dest,
 222                                        BasicType& copy_type,
 223                                        const Type*& value_type,
 224                                        bool& disjoint_bases) {
 225   Node* src = in(ArrayCopyNode::Src);
 226   Node* dest = in(ArrayCopyNode::Dest);
 227   const Type* src_type = phase->type(src);
 228   const TypeAryPtr* ary_src = src_type->isa_aryptr();
 229 
 230   if (is_arraycopy() || is_copyofrange() || is_copyof()) {
 231     const Type* dest_type = phase->type(dest);
 232     const TypeAryPtr* ary_dest = dest_type->isa_aryptr();
 233     Node* src_offset = in(ArrayCopyNode::SrcPos);
 234     Node* dest_offset = in(ArrayCopyNode::DestPos);
 235 
 236     // newly allocated object is guaranteed to not overlap with source object
 237     disjoint_bases = is_alloc_tightly_coupled();
 238 
 239     if (ary_src  == NULL || ary_src->klass()  == NULL ||
 240         ary_dest == NULL || ary_dest->klass() == NULL) {
 241       // We don't know if arguments are arrays
 242       return false;
 243     }
 244 
 245     BasicType src_elem  = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 246     BasicType dest_elem = ary_dest->klass()->as_array_klass()->element_type()->basic_type();
 247     if (src_elem  == T_ARRAY)  src_elem  = T_OBJECT;
 248     if (dest_elem == T_ARRAY)  dest_elem = T_OBJECT;
 249 
 250     if (src_elem != dest_elem || dest_elem == T_VOID) {
 251       // We don't know if arguments are arrays of the same type
 252       return false;
 253     }
 254 
 255     if (dest_elem == T_OBJECT && (!is_alloc_tightly_coupled() || !GraphKit::use_ReduceInitialCardMarks())) {
 256       // It's an object array copy but we can't emit the card marking
 257       // that is needed
 258       return false;
 259     }
 260 
 261     value_type = ary_src->elem();
 262 
 263     base_src = src;
 264     base_dest = dest;
 265 
 266     uint shift  = exact_log2(type2aelembytes(dest_elem));
 267     uint header = arrayOopDesc::base_offset_in_bytes(dest_elem);
 268 
 269     adr_src = src;
 270     adr_dest = dest;
 271 
 272     src_offset = Compile::conv_I2X_index(phase, src_offset, ary_src->size());
 273     dest_offset = Compile::conv_I2X_index(phase, dest_offset, ary_dest->size());
 274 
 275     Node* src_scale = phase->transform(new LShiftXNode(src_offset, phase->intcon(shift)));
 276     Node* dest_scale = phase->transform(new LShiftXNode(dest_offset, phase->intcon(shift)));
 277 
 278     adr_src = phase->transform(new AddPNode(base_src, adr_src, src_scale));
 279     adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, dest_scale));
 280 
 281     adr_src = new AddPNode(base_src, adr_src, phase->MakeConX(header));
 282     adr_dest = new AddPNode(base_dest, adr_dest, phase->MakeConX(header));
 283 
 284     adr_src = phase->transform(adr_src);
 285     adr_dest = phase->transform(adr_dest);
 286 
 287     copy_type = dest_elem;
 288   } else {
 289     assert(ary_src != NULL, "should be a clone");
 290     assert(is_clonebasic(), "should be");
 291 
 292     disjoint_bases = true;
 293     assert(src->is_AddP(), "should be base + off");
 294     assert(dest->is_AddP(), "should be base + off");
 295     adr_src = src;
 296     base_src = src->in(AddPNode::Base);
 297     adr_dest = dest;
 298     base_dest = dest->in(AddPNode::Base);
 299 
 300     assert(phase->type(src->in(AddPNode::Offset))->is_intptr_t()->get_con() == phase->type(dest->in(AddPNode::Offset))->is_intptr_t()->get_con(), "same start offset?");
 301     BasicType elem = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 302     if (elem == T_ARRAY)  elem = T_OBJECT;
 303 
 304     int diff = arrayOopDesc::base_offset_in_bytes(elem) - phase->type(src->in(AddPNode::Offset))->is_intptr_t()->get_con();
 305     assert(diff >= 0, "clone should not start after 1st array element");
 306     if (diff > 0) {
 307       adr_src = phase->transform(new AddPNode(base_src, adr_src, phase->MakeConX(diff)));
 308       adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, phase->MakeConX(diff)));
 309     }
 310 
 311     copy_type = elem;
 312     value_type = ary_src->elem();
 313   }
 314   return true;
 315 }
 316 
 317 const TypePtr* ArrayCopyNode::get_address_type(PhaseGVN *phase, Node* n) {
 318   const Type* at = phase->type(n);
 319   assert(at != Type::TOP, "unexpected type");
 320   const TypePtr* atp = at->isa_ptr();
 321   // adjust atp to be the correct array element address type
 322   atp = atp->add_offset(Type::OffsetBot);
 323   return atp;
 324 }
 325 
 326 void ArrayCopyNode::array_copy_test_overlap(PhaseGVN *phase, bool can_reshape, bool disjoint_bases, int count, Node*& forward_ctl, Node*& backward_ctl) {
 327   Node* ctl = in(TypeFunc::Control);
 328   if (!disjoint_bases && count > 1) {
 329     Node* src_offset = in(ArrayCopyNode::SrcPos);
 330     Node* dest_offset = in(ArrayCopyNode::DestPos);
 331     assert(src_offset != NULL && dest_offset != NULL, "should be");
 332     Node* cmp = phase->transform(new CmpINode(src_offset, dest_offset));
 333     Node *bol = phase->transform(new BoolNode(cmp, BoolTest::lt));
 334     IfNode *iff = new IfNode(ctl, bol, PROB_FAIR, COUNT_UNKNOWN);
 335 
 336     phase->transform(iff);
 337 
 338     forward_ctl = phase->transform(new IfFalseNode(iff));
 339     backward_ctl = phase->transform(new IfTrueNode(iff));
 340   } else {
 341     forward_ctl = ctl;
 342   }
 343 }
 344 
 345 Node* ArrayCopyNode::array_copy_forward(PhaseGVN *phase,
 346                                         bool can_reshape,
 347                                         Node* forward_ctl,
 348                                         Node* start_mem_src,
 349                                         Node* start_mem_dest,
 350                                         const TypePtr* atp_src,
 351                                         const TypePtr* atp_dest,
 352                                         Node* adr_src,
 353                                         Node* base_src,
 354                                         Node* adr_dest,
 355                                         Node* base_dest,
 356                                         BasicType copy_type,
 357                                         const Type* value_type,
 358                                         int count) {
 359   Node* mem = phase->C->top();
 360   if (!forward_ctl->is_top()) {
 361     // copy forward
 362     mem = start_mem_dest;
 363 
 364     if (count > 0) {
 365       Node* v = LoadNode::make(*phase, forward_ctl, start_mem_src, adr_src, atp_src, value_type, copy_type, MemNode::unordered);
 366       v = phase->transform(v);
 367       mem = StoreNode::make(*phase, forward_ctl, mem, adr_dest, atp_dest, v, copy_type, MemNode::unordered);
 368       mem = phase->transform(mem);
 369       for (int i = 1; i < count; i++) {
 370         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 371         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 372         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 373         v = LoadNode::make(*phase, forward_ctl, mem, next_src, atp_src, value_type, copy_type, MemNode::unordered);
 374         v = phase->transform(v);
 375         mem = StoreNode::make(*phase, forward_ctl,mem,next_dest,atp_dest,v, copy_type, MemNode::unordered);
 376         mem = phase->transform(mem);
 377       }
 378     } else if(can_reshape) {
 379       PhaseIterGVN* igvn = phase->is_IterGVN();
 380       igvn->_worklist.push(adr_src);
 381       igvn->_worklist.push(adr_dest);
 382     }
 383   }
 384   return mem;
 385 }
 386 
 387 Node* ArrayCopyNode::array_copy_backward(PhaseGVN *phase,
 388                                          bool can_reshape,
 389                                          Node* backward_ctl,
 390                                          Node* start_mem_src,
 391                                          Node* start_mem_dest,
 392                                          const TypePtr* atp_src,
 393                                          const TypePtr* atp_dest,
 394                                          Node* adr_src,
 395                                          Node* base_src,
 396                                          Node* adr_dest,
 397                                          Node* base_dest,
 398                                          BasicType copy_type,
 399                                          const Type* value_type,
 400                                          int count) {
 401   Node* mem = phase->C->top();
 402   if (!backward_ctl->is_top()) {
 403     // copy backward
 404     mem = start_mem_dest;
 405 
 406     if (count > 0) {
 407       for (int i = count-1; i >= 1; i--) {
 408         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 409         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 410         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 411         Node* v = LoadNode::make(*phase, backward_ctl, mem, next_src, atp_src, value_type, copy_type, MemNode::unordered);
 412         v = phase->transform(v);
 413         mem = StoreNode::make(*phase, backward_ctl,mem,next_dest,atp_dest,v, copy_type, MemNode::unordered);
 414         mem = phase->transform(mem);
 415       }
 416       Node* v = LoadNode::make(*phase, backward_ctl, mem, adr_src, atp_src, value_type, copy_type, MemNode::unordered);
 417       v = phase->transform(v);
 418       mem = StoreNode::make(*phase, backward_ctl, mem, adr_dest, atp_dest, v, copy_type, MemNode::unordered);
 419       mem = phase->transform(mem);
 420     } else if(can_reshape) {
 421       PhaseIterGVN* igvn = phase->is_IterGVN();
 422       igvn->_worklist.push(adr_src);
 423       igvn->_worklist.push(adr_dest);
 424     }
 425   }
 426   return mem;
 427 }
 428 
 429 bool ArrayCopyNode::finish_transform(PhaseGVN *phase, bool can_reshape,
 430                                      Node* ctl, Node *mem) {
 431   if (can_reshape) {
 432     PhaseIterGVN* igvn = phase->is_IterGVN();
 433     igvn->set_delay_transform(false);
 434     if (is_clonebasic()) {
 435       Node* out_mem = proj_out(TypeFunc::Memory);
 436 
 437       if (out_mem->outcnt() != 1 || !out_mem->raw_out(0)->is_MergeMem() ||
 438           out_mem->raw_out(0)->outcnt() != 1 || !out_mem->raw_out(0)->raw_out(0)->is_MemBar()) {
 439         assert(!GraphKit::use_ReduceInitialCardMarks(), "can only happen with card marking");
 440         return false;
 441       }
 442 
 443       igvn->replace_node(out_mem->raw_out(0), mem);
 444 
 445       Node* out_ctl = proj_out(TypeFunc::Control);
 446       igvn->replace_node(out_ctl, ctl);
 447     } else {
 448       // replace fallthrough projections of the ArrayCopyNode by the
 449       // new memory, control and the input IO.
 450       CallProjections callprojs;
 451       extract_projections(&callprojs, true, false);
 452 
 453       if (callprojs.fallthrough_ioproj != NULL) {
 454         igvn->replace_node(callprojs.fallthrough_ioproj, in(TypeFunc::I_O));
 455       }
 456       if (callprojs.fallthrough_memproj != NULL) {
 457         igvn->replace_node(callprojs.fallthrough_memproj, mem);
 458       }
 459       if (callprojs.fallthrough_catchproj != NULL) {
 460         igvn->replace_node(callprojs.fallthrough_catchproj, ctl);
 461       }
 462 
 463       // The ArrayCopyNode is not disconnected. It still has the
 464       // projections for the exception case. Replace current
 465       // ArrayCopyNode with a dummy new one with a top() control so
 466       // that this part of the graph stays consistent but is
 467       // eventually removed.
 468 
 469       set_req(0, phase->C->top());
 470       remove_dead_region(phase, can_reshape);
 471     }
 472   } else {
 473     if (in(TypeFunc::Control) != ctl) {
 474       // we can't return new memory and control from Ideal at parse time
 475       assert(!is_clonebasic(), "added control for clone?");
 476       return false;
 477     }
 478   }
 479   return true;
 480 }
 481 
 482 
 483 Node *ArrayCopyNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 484   if (remove_dead_region(phase, can_reshape))  return this;
 485 
 486   if (StressArrayCopyMacroNode && !can_reshape) {
 487     phase->record_for_igvn(this);
 488     return NULL;
 489   }
 490 
 491   // See if it's a small array copy and we can inline it as
 492   // loads/stores
 493   // Here we can only do:
 494   // - arraycopy if all arguments were validated before and we don't
 495   // need card marking
 496   // - clone for which we don't need to do card marking
 497 
 498   if (!is_clonebasic() && !is_arraycopy_validated() &&
 499       !is_copyofrange_validated() && !is_copyof_validated()) {
 500     return NULL;
 501   }
 502 
 503   assert(in(TypeFunc::Control) != NULL &&
 504          in(TypeFunc::Memory) != NULL &&
 505          in(ArrayCopyNode::Src) != NULL &&
 506          in(ArrayCopyNode::Dest) != NULL &&
 507          in(ArrayCopyNode::Length) != NULL &&
 508          ((in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::DestPos) != NULL) ||
 509           is_clonebasic()), "broken inputs");
 510 
 511   if (in(TypeFunc::Control)->is_top() ||
 512       in(TypeFunc::Memory)->is_top() ||
 513       phase->type(in(ArrayCopyNode::Src)) == Type::TOP ||
 514       phase->type(in(ArrayCopyNode::Dest)) == Type::TOP ||
 515       (in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::SrcPos)->is_top()) ||
 516       (in(ArrayCopyNode::DestPos) != NULL && in(ArrayCopyNode::DestPos)->is_top())) {
 517     return NULL;
 518   }
 519 
 520   int count = get_count(phase);
 521 
 522   if (count < 0 || count > ArrayCopyLoadStoreMaxElem) {
 523     return NULL;
 524   }
 525 
 526   Node* mem = try_clone_instance(phase, can_reshape, count);
 527   if (mem != NULL) {
 528     return (mem == NodeSentinel) ? NULL : mem;
 529   }
 530 
 531   Node* adr_src = NULL;
 532   Node* base_src = NULL;
 533   Node* adr_dest = NULL;
 534   Node* base_dest = NULL;
 535   BasicType copy_type = T_ILLEGAL;
 536   const Type* value_type = NULL;
 537   bool disjoint_bases = false;
 538 
 539   if (!prepare_array_copy(phase, can_reshape,
 540                           adr_src, base_src, adr_dest, base_dest,
 541                           copy_type, value_type, disjoint_bases)) {
 542     return NULL;
 543   }
 544 
 545   Node* src = in(ArrayCopyNode::Src);
 546   Node* dest = in(ArrayCopyNode::Dest);
 547   const TypePtr* atp_src = get_address_type(phase, src);
 548   const TypePtr* atp_dest = get_address_type(phase, dest);
 549   uint alias_idx_src = phase->C->get_alias_index(atp_src);
 550   uint alias_idx_dest = phase->C->get_alias_index(atp_dest);
 551 
 552   Node *in_mem = in(TypeFunc::Memory);
 553   Node *start_mem_src = in_mem;
 554   Node *start_mem_dest = in_mem;
 555   if (in_mem->is_MergeMem()) {
 556     start_mem_src = in_mem->as_MergeMem()->memory_at(alias_idx_src);
 557     start_mem_dest = in_mem->as_MergeMem()->memory_at(alias_idx_dest);
 558   }
 559 
 560 
 561   if (can_reshape) {
 562     assert(!phase->is_IterGVN()->delay_transform(), "cannot delay transforms");
 563     phase->is_IterGVN()->set_delay_transform(true);
 564   }
 565 
 566   Node* backward_ctl = phase->C->top();
 567   Node* forward_ctl = phase->C->top();
 568   array_copy_test_overlap(phase, can_reshape, disjoint_bases, count, forward_ctl, backward_ctl);
 569 
 570   Node* forward_mem = array_copy_forward(phase, can_reshape, forward_ctl,
 571                                          start_mem_src, start_mem_dest,
 572                                          atp_src, atp_dest,
 573                                          adr_src, base_src, adr_dest, base_dest,
 574                                          copy_type, value_type, count);
 575 
 576   Node* backward_mem = array_copy_backward(phase, can_reshape, backward_ctl,
 577                                            start_mem_src, start_mem_dest,
 578                                            atp_src, atp_dest,
 579                                            adr_src, base_src, adr_dest, base_dest,
 580                                            copy_type, value_type, count);
 581 
 582   Node* ctl = NULL;
 583   if (!forward_ctl->is_top() && !backward_ctl->is_top()) {
 584     ctl = new RegionNode(3);
 585     mem = new PhiNode(ctl, Type::MEMORY, atp_dest);
 586     ctl->init_req(1, forward_ctl);
 587     mem->init_req(1, forward_mem);
 588     ctl->init_req(2, backward_ctl);
 589     mem->init_req(2, backward_mem);
 590     ctl = phase->transform(ctl);
 591     mem = phase->transform(mem);
 592   } else if (!forward_ctl->is_top()) {
 593     ctl = forward_ctl;
 594     mem = forward_mem;
 595   } else {
 596     assert(!backward_ctl->is_top(), "no copy?");
 597     ctl = backward_ctl;
 598     mem = backward_mem;
 599   }
 600 
 601   if (can_reshape) {
 602     assert(phase->is_IterGVN()->delay_transform(), "should be delaying transforms");
 603     phase->is_IterGVN()->set_delay_transform(false);
 604   }
 605 
 606   MergeMemNode* out_mem = MergeMemNode::make(in_mem);
 607   out_mem->set_memory_at(alias_idx_dest, mem);
 608   mem = out_mem;
 609 
 610   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 611     return NULL;
 612   }
 613 
 614   return mem;
 615 }
 616 
 617 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 618   Node* dest = in(ArrayCopyNode::Dest);
 619   if (dest->is_top()) {
 620     return false;
 621   }
 622   const TypeOopPtr* dest_t = phase->type(dest)->is_oopptr();
 623   assert(!dest_t->is_known_instance() || _dest_type->is_known_instance(), "result of EA not recorded");
 624   assert(in(ArrayCopyNode::Src)->is_top() || !phase->type(in(ArrayCopyNode::Src))->is_oopptr()->is_known_instance() ||
 625          _src_type->is_known_instance(), "result of EA not recorded");
 626 
 627   if (_dest_type != TypeOopPtr::BOTTOM || t_oop->is_known_instance()) {
 628     assert(_dest_type == TypeOopPtr::BOTTOM || _dest_type->is_known_instance(), "result of EA is known instance");
 629     return t_oop->instance_id() == _dest_type->instance_id();
 630   }
 631 
 632   return CallNode::may_modify_arraycopy_helper(dest_t, t_oop, phase);
 633 }
 634 
 635 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr *t_oop, Node* n, PhaseTransform *phase, CallNode*& call) {
 636   if (n != NULL &&
 637       n->is_Call() &&
 638       n->as_Call()->may_modify(t_oop, phase) &&
 639       (n->as_Call()->is_ArrayCopy() || n->as_Call()->is_call_to_arraycopystub())) {
 640     call = n->as_Call();
 641     return true;
 642   }
 643   return false;
 644 }
 645 
 646 static Node* step_over_gc_barrier(Node* c) {
 647   if (UseG1GC && !GraphKit::use_ReduceInitialCardMarks() &&
 648       c != NULL && c->is_Region() && c->req() == 3) {
 649     for (uint i = 1; i < c->req(); i++) {
 650       if (c->in(i) != NULL && c->in(i)->is_Region() &&
 651           c->in(i)->req() == 3) {
 652         Node* r = c->in(i);
 653         for (uint j = 1; j < r->req(); j++) {
 654           if (r->in(j) != NULL && r->in(j)->is_Proj() &&
 655               r->in(j)->in(0) != NULL &&
 656               r->in(j)->in(0)->Opcode() == Op_CallLeaf &&
 657               r->in(j)->in(0)->as_Call()->entry_point() == CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post)) {
 658             Node* call = r->in(j)->in(0);
 659             c = c->in(i == 1 ? 2 : 1);
 660             if (c != NULL) {
 661               c = c->in(0);
 662               if (c != NULL) {
 663                 c = c->in(0);
 664                 assert(call->in(0) == NULL ||
 665                        call->in(0)->in(0) == NULL ||
 666                        call->in(0)->in(0)->in(0) == NULL ||
 667                        call->in(0)->in(0)->in(0)->in(0) == NULL ||
 668                        call->in(0)->in(0)->in(0)->in(0)->in(0) == NULL ||
 669                        c == call->in(0)->in(0)->in(0)->in(0)->in(0), "bad barrier shape");
 670                 return c;
 671               }
 672             }
 673           }
 674         }
 675       }
 676     }
 677   }
 678   return c;
 679 }
 680 
 681 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, MemBarNode* mb, PhaseTransform *phase, ArrayCopyNode*& ac) {
 682 
 683   Node* c = mb->in(0);
 684 
 685   // step over g1 gc barrier if we're at a clone with ReduceInitialCardMarks off
 686   c = step_over_gc_barrier(c);
 687 
 688   CallNode* call = NULL;
 689   if (c != NULL && c->is_Region()) {
 690     for (uint i = 1; i < c->req(); i++) {
 691       if (c->in(i) != NULL) {
 692         Node* n = c->in(i)->in(0);
 693         if (may_modify_helper(t_oop, n, phase, call)) {
 694           ac = call->isa_ArrayCopy();
 695           assert(c == mb->in(0), "only for clone");
 696           return true;
 697         }
 698       }
 699     }
 700   } else if (may_modify_helper(t_oop, c->in(0), phase, call)) {
 701     ac = call->isa_ArrayCopy();
 702     assert(c == mb->in(0) || (ac != NULL && ac->is_clonebasic() && !GraphKit::use_ReduceInitialCardMarks()), "only for clone");
 703     return true;
 704   }
 705 
 706   return false;
 707 }
 708 
 709 // Does this array copy modify offsets between offset_lo and offset_hi
 710 // in the destination array
 711 // if must_modify is false, return true if the copy could write
 712 // between offset_lo and offset_hi
 713 // if must_modify is true, return true if the copy is guaranteed to
 714 // write between offset_lo and offset_hi
 715 bool ArrayCopyNode::modifies(intptr_t offset_lo, intptr_t offset_hi, PhaseTransform* phase, bool must_modify) const {
 716   assert(_kind == ArrayCopy || _kind == CopyOf || _kind == CopyOfRange, "only for real array copies");
 717 
 718   Node* dest = in(Dest);
 719   Node* dest_pos = in(DestPos);
 720   Node* len = in(Length);
 721 
 722   const TypeInt *dest_pos_t = phase->type(dest_pos)->isa_int();
 723   const TypeInt *len_t = phase->type(len)->isa_int();
 724   const TypeAryPtr* ary_t = phase->type(dest)->isa_aryptr();
 725 
 726   if (dest_pos_t == NULL || len_t == NULL || ary_t == NULL) {
 727     return !must_modify;
 728   }
 729 
 730   BasicType ary_elem = ary_t->klass()->as_array_klass()->element_type()->basic_type();
 731   uint header = arrayOopDesc::base_offset_in_bytes(ary_elem);
 732   uint elemsize = type2aelembytes(ary_elem);
 733 
 734   jlong dest_pos_plus_len_lo = (((jlong)dest_pos_t->_lo) + len_t->_lo) * elemsize + header;
 735   jlong dest_pos_plus_len_hi = (((jlong)dest_pos_t->_hi) + len_t->_hi) * elemsize + header;
 736   jlong dest_pos_lo = ((jlong)dest_pos_t->_lo) * elemsize + header;
 737   jlong dest_pos_hi = ((jlong)dest_pos_t->_hi) * elemsize + header;
 738 
 739   if (must_modify) {
 740     if (offset_lo >= dest_pos_hi && offset_hi < dest_pos_plus_len_lo) {
 741       return true;
 742     }
 743   } else {
 744     if (offset_hi >= dest_pos_lo && offset_lo < dest_pos_plus_len_hi) {
 745       return true;
 746     }
 747   }
 748   return false;
 749 }
 750