1 /*
   2  * Copyright (c) 2016, 2018, 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 "opto/arraycopynode.hpp"
  30 #include "opto/graphKit.hpp"
  31 #include "runtime/sharedRuntime.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 ArrayCopyNode::ArrayCopyNode(Compile* C, bool alloc_tightly_coupled, bool has_negative_length_guard)
  35   : CallNode(arraycopy_type(), NULL, TypePtr::BOTTOM),
  36     _kind(None),
  37     _alloc_tightly_coupled(alloc_tightly_coupled),
  38     _has_negative_length_guard(has_negative_length_guard),
  39     _arguments_validated(false),
  40     _src_type(TypeOopPtr::BOTTOM),
  41     _dest_type(TypeOopPtr::BOTTOM) {
  42   init_class_id(Class_ArrayCopy);
  43   init_flags(Flag_is_macro);
  44   C->add_macro_node(this);
  45 }
  46 
  47 uint ArrayCopyNode::size_of() const { return sizeof(*this); }
  48 
  49 ArrayCopyNode* ArrayCopyNode::make(GraphKit* kit, bool may_throw,
  50                                    Node* src, Node* src_offset,
  51                                    Node* dest, Node* dest_offset,
  52                                    Node* length,
  53                                    bool alloc_tightly_coupled,
  54                                    bool has_negative_length_guard,
  55                                    Node* src_klass, Node* dest_klass,
  56                                    Node* src_length, Node* dest_length) {
  57 
  58   ArrayCopyNode* ac = new ArrayCopyNode(kit->C, alloc_tightly_coupled, has_negative_length_guard);
  59   Node* prev_mem = kit->set_predefined_input_for_runtime_call(ac);
  60 
  61   ac->init_req(ArrayCopyNode::Src, src);
  62   ac->init_req(ArrayCopyNode::SrcPos, src_offset);
  63   ac->init_req(ArrayCopyNode::Dest, dest);
  64   ac->init_req(ArrayCopyNode::DestPos, dest_offset);
  65   ac->init_req(ArrayCopyNode::Length, length);
  66   ac->init_req(ArrayCopyNode::SrcLen, src_length);
  67   ac->init_req(ArrayCopyNode::DestLen, dest_length);
  68   ac->init_req(ArrayCopyNode::SrcKlass, src_klass);
  69   ac->init_req(ArrayCopyNode::DestKlass, dest_klass);
  70 
  71   if (may_throw) {
  72     ac->set_req(TypeFunc::I_O , kit->i_o());
  73     kit->add_safepoint_edges(ac, false);
  74   }
  75 
  76   return ac;
  77 }
  78 
  79 void ArrayCopyNode::connect_outputs(GraphKit* kit) {
  80   kit->set_all_memory_call(this, true);
  81   kit->set_control(kit->gvn().transform(new ProjNode(this,TypeFunc::Control)));
  82   kit->set_i_o(kit->gvn().transform(new ProjNode(this, TypeFunc::I_O)));
  83   kit->make_slow_call_ex(this, kit->env()->Throwable_klass(), true);
  84   kit->set_all_memory_call(this);
  85 }
  86 
  87 #ifndef PRODUCT
  88 const char* ArrayCopyNode::_kind_names[] = {"arraycopy", "arraycopy, validated arguments", "clone", "oop array clone", "CopyOf", "CopyOfRange"};
  89 
  90 void ArrayCopyNode::dump_spec(outputStream *st) const {
  91   CallNode::dump_spec(st);
  92   st->print(" (%s%s)", _kind_names[_kind], _alloc_tightly_coupled ? ", tightly coupled allocation" : "");
  93 }
  94 
  95 void ArrayCopyNode::dump_compact_spec(outputStream* st) const {
  96   st->print("%s%s", _kind_names[_kind], _alloc_tightly_coupled ? ",tight" : "");
  97 }
  98 #endif
  99 
 100 intptr_t ArrayCopyNode::get_length_if_constant(PhaseGVN *phase) const {
 101   // check that length is constant
 102   Node* length = in(ArrayCopyNode::Length);
 103   const Type* length_type = phase->type(length);
 104 
 105   if (length_type == Type::TOP) {
 106     return -1;
 107   }
 108 
 109   assert(is_clonebasic() || is_arraycopy() || is_copyof() || is_copyofrange(), "unexpected array copy type");
 110 
 111   return is_clonebasic() ? length->find_intptr_t_con(-1) : length->find_int_con(-1);
 112 }
 113 
 114 int ArrayCopyNode::get_count(PhaseGVN *phase) const {
 115   Node* src = in(ArrayCopyNode::Src);
 116   const Type* src_type = phase->type(src);
 117 
 118   if (is_clonebasic()) {
 119     if (src_type->isa_instptr()) {
 120       const TypeInstPtr* inst_src = src_type->is_instptr();
 121       ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 122       // ciInstanceKlass::nof_nonstatic_fields() doesn't take injected
 123       // fields into account. They are rare anyway so easier to simply
 124       // skip instances with injected fields.
 125       if ((!inst_src->klass_is_exact() && (ik->is_interface() || ik->has_subklass())) || ik->has_injected_fields()) {
 126         return -1;
 127       }
 128       int nb_fields = ik->nof_nonstatic_fields();
 129       return nb_fields;
 130     } else {
 131       const TypeAryPtr* ary_src = src_type->isa_aryptr();
 132       assert (ary_src != NULL, "not an array or instance?");
 133       // clone passes a length as a rounded number of longs. If we're
 134       // cloning an array we'll do it element by element. If the
 135       // length input to ArrayCopyNode is constant, length of input
 136       // array must be too.
 137 
 138       assert((get_length_if_constant(phase) == -1) == !ary_src->size()->is_con() ||
 139              phase->is_IterGVN(), "inconsistent");
 140 
 141       if (ary_src->size()->is_con()) {
 142         return ary_src->size()->get_con();
 143       }
 144       return -1;
 145     }
 146   }
 147 
 148   return get_length_if_constant(phase);
 149 }
 150 
 151 Node* ArrayCopyNode::try_clone_instance(PhaseGVN *phase, bool can_reshape, int count) {
 152   if (!is_clonebasic()) {
 153     return NULL;
 154   }
 155 
 156   Node* src = in(ArrayCopyNode::Src);
 157   Node* dest = in(ArrayCopyNode::Dest);
 158   Node* ctl = in(TypeFunc::Control);
 159   Node* in_mem = in(TypeFunc::Memory);
 160 
 161   const Type* src_type = phase->type(src);
 162 
 163   assert(src->is_AddP(), "should be base + off");
 164   assert(dest->is_AddP(), "should be base + off");
 165   Node* base_src = src->in(AddPNode::Base);
 166   Node* base_dest = dest->in(AddPNode::Base);
 167 
 168   MergeMemNode* mem = MergeMemNode::make(in_mem);
 169 
 170   const TypeInstPtr* inst_src = src_type->isa_instptr();
 171 
 172   if (inst_src == NULL) {
 173     return NULL;
 174   }
 175 
 176   if (!inst_src->klass_is_exact()) {
 177     ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 178     assert(!ik->is_interface() && !ik->has_subklass(), "inconsistent klass hierarchy");
 179     phase->C->dependencies()->assert_leaf_type(ik);
 180   }
 181 
 182   ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 183   assert(ik->nof_nonstatic_fields() <= ArrayCopyLoadStoreMaxElem, "too many fields");
 184 
 185   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 186   for (int i = 0; i < count; i++) {
 187     ciField* field = ik->nonstatic_field_at(i);
 188     int fieldidx = phase->C->alias_type(field)->index();
 189     const TypePtr* adr_type = phase->C->alias_type(field)->adr_type();
 190     Node* off = phase->MakeConX(field->offset());
 191     Node* next_src = phase->transform(new AddPNode(base_src,base_src,off));
 192     Node* next_dest = phase->transform(new AddPNode(base_dest,base_dest,off));
 193     BasicType bt = field->layout_type();
 194 
 195     const Type *type;
 196     if (bt == T_OBJECT) {
 197       if (!field->type()->is_loaded()) {
 198         type = TypeInstPtr::BOTTOM;
 199       } else {
 200         ciType* field_klass = field->type();
 201         type = TypeOopPtr::make_from_klass(field_klass->as_klass());
 202       }
 203     } else {
 204       type = Type::get_const_basic_type(bt);
 205     }
 206 
 207     Node* v = LoadNode::make(*phase, ctl, mem->memory_at(fieldidx), next_src, adr_type, type, bt, MemNode::unordered);
 208     v = phase->transform(v);
 209     if (bt == T_OBJECT) {
 210       v = bs->array_copy_load_store_barrier(phase, can_reshape, v, mem, ctl);
 211     }
 212     Node* s = StoreNode::make(*phase, ctl, mem->memory_at(fieldidx), next_dest, adr_type, v, bt, MemNode::unordered);
 213     s = phase->transform(s);
 214     mem->set_memory_at(fieldidx, s);
 215   }
 216 
 217   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 218     // Return NodeSentinel to indicate that the transform failed
 219     return NodeSentinel;
 220   }
 221 
 222   return mem;
 223 }
 224 
 225 bool ArrayCopyNode::prepare_array_copy(PhaseGVN *phase, bool can_reshape,
 226                                        Node*& adr_src,
 227                                        Node*& base_src,
 228                                        Node*& adr_dest,
 229                                        Node*& base_dest,
 230                                        BasicType& copy_type,
 231                                        const Type*& value_type,
 232                                        bool& disjoint_bases) {
 233   Node* src = in(ArrayCopyNode::Src);
 234   Node* dest = in(ArrayCopyNode::Dest);
 235   const Type* src_type = phase->type(src);
 236   const TypeAryPtr* ary_src = src_type->isa_aryptr();
 237 
 238   if (is_arraycopy() || is_copyofrange() || is_copyof()) {
 239     const Type* dest_type = phase->type(dest);
 240     const TypeAryPtr* ary_dest = dest_type->isa_aryptr();
 241     Node* src_offset = in(ArrayCopyNode::SrcPos);
 242     Node* dest_offset = in(ArrayCopyNode::DestPos);
 243 
 244     // newly allocated object is guaranteed to not overlap with source object
 245     disjoint_bases = is_alloc_tightly_coupled();
 246 
 247     if (ary_src  == NULL || ary_src->klass()  == NULL ||
 248         ary_dest == NULL || ary_dest->klass() == NULL) {
 249       // We don't know if arguments are arrays
 250       return false;
 251     }
 252 
 253     BasicType src_elem  = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 254     BasicType dest_elem = ary_dest->klass()->as_array_klass()->element_type()->basic_type();
 255     if (src_elem  == T_ARRAY)  src_elem  = T_OBJECT;
 256     if (dest_elem == T_ARRAY)  dest_elem = T_OBJECT;
 257 
 258     if (src_elem != dest_elem || dest_elem == T_VOID) {
 259       // We don't know if arguments are arrays of the same type
 260       return false;
 261     }
 262 
 263     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 264     if (bs->array_copy_requires_gc_barriers(is_alloc_tightly_coupled(), dest_elem, false, BarrierSetC2::Optimization)) {
 265       // It's an object array copy but we can't emit the card marking
 266       // that is needed
 267       return false;
 268     }
 269 
 270     value_type = ary_src->elem();
 271 
 272     base_src = src;
 273     base_dest = dest;
 274 
 275     uint shift  = exact_log2(type2aelembytes(dest_elem));
 276     uint header = arrayOopDesc::base_offset_in_bytes(dest_elem);
 277 
 278     adr_src = src;
 279     adr_dest = dest;
 280 
 281     src_offset = Compile::conv_I2X_index(phase, src_offset, ary_src->size());
 282     dest_offset = Compile::conv_I2X_index(phase, dest_offset, ary_dest->size());
 283 
 284     Node* src_scale = phase->transform(new LShiftXNode(src_offset, phase->intcon(shift)));
 285     Node* dest_scale = phase->transform(new LShiftXNode(dest_offset, phase->intcon(shift)));
 286 
 287     adr_src = phase->transform(new AddPNode(base_src, adr_src, src_scale));
 288     adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, dest_scale));
 289 
 290     adr_src = new AddPNode(base_src, adr_src, phase->MakeConX(header));
 291     adr_dest = new AddPNode(base_dest, adr_dest, phase->MakeConX(header));
 292 
 293     adr_src = phase->transform(adr_src);
 294     adr_dest = phase->transform(adr_dest);
 295 
 296     copy_type = dest_elem;
 297   } else {
 298     assert(ary_src != NULL, "should be a clone");
 299     assert(is_clonebasic(), "should be");
 300 
 301     disjoint_bases = true;
 302     assert(src->is_AddP(), "should be base + off");
 303     assert(dest->is_AddP(), "should be base + off");
 304     adr_src = src;
 305     base_src = src->in(AddPNode::Base);
 306     adr_dest = dest;
 307     base_dest = dest->in(AddPNode::Base);
 308 
 309     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?");
 310     BasicType elem = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 311     if (elem == T_ARRAY)  elem = T_OBJECT;
 312 
 313     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 314     if (bs->array_copy_requires_gc_barriers(true, elem, true, BarrierSetC2::Optimization)) {
 315       return false;
 316     }
 317 
 318     int diff = arrayOopDesc::base_offset_in_bytes(elem) - phase->type(src->in(AddPNode::Offset))->is_intptr_t()->get_con();
 319     assert(diff >= 0, "clone should not start after 1st array element");
 320     if (diff > 0) {
 321       adr_src = phase->transform(new AddPNode(base_src, adr_src, phase->MakeConX(diff)));
 322       adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, phase->MakeConX(diff)));
 323     }
 324 
 325     copy_type = elem;
 326     value_type = ary_src->elem();
 327   }
 328   return true;
 329 }
 330 
 331 const TypePtr* ArrayCopyNode::get_address_type(PhaseGVN *phase, Node* n) {
 332   const Type* at = phase->type(n);
 333   assert(at != Type::TOP, "unexpected type");
 334   const TypePtr* atp = at->isa_ptr();
 335   // adjust atp to be the correct array element address type
 336   atp = atp->add_offset(Type::OffsetBot);
 337   return atp;
 338 }
 339 
 340 void ArrayCopyNode::array_copy_test_overlap(PhaseGVN *phase, bool can_reshape, bool disjoint_bases, int count, Node*& forward_ctl, Node*& backward_ctl) {
 341   Node* ctl = in(TypeFunc::Control);
 342   if (!disjoint_bases && count > 1) {
 343     Node* src_offset = in(ArrayCopyNode::SrcPos);
 344     Node* dest_offset = in(ArrayCopyNode::DestPos);
 345     assert(src_offset != NULL && dest_offset != NULL, "should be");
 346     Node* cmp = phase->transform(new CmpINode(src_offset, dest_offset));
 347     Node *bol = phase->transform(new BoolNode(cmp, BoolTest::lt));
 348     IfNode *iff = new IfNode(ctl, bol, PROB_FAIR, COUNT_UNKNOWN);
 349 
 350     phase->transform(iff);
 351 
 352     forward_ctl = phase->transform(new IfFalseNode(iff));
 353     backward_ctl = phase->transform(new IfTrueNode(iff));
 354   } else {
 355     forward_ctl = ctl;
 356   }
 357 }
 358 
 359 Node* ArrayCopyNode::array_copy_forward(PhaseGVN *phase,
 360                                         bool can_reshape,
 361                                         Node*& forward_ctl,
 362                                         MergeMemNode* mm,
 363                                         const TypePtr* atp_src,
 364                                         const TypePtr* atp_dest,
 365                                         Node* adr_src,
 366                                         Node* base_src,
 367                                         Node* adr_dest,
 368                                         Node* base_dest,
 369                                         BasicType copy_type,
 370                                         const Type* value_type,
 371                                         int count) {
 372   if (!forward_ctl->is_top()) {
 373     // copy forward
 374     mm = mm->clone()->as_MergeMem();
 375     uint alias_idx_src = phase->C->get_alias_index(atp_src);
 376     uint alias_idx_dest = phase->C->get_alias_index(atp_dest);
 377     Node *start_mem_src = mm->memory_at(alias_idx_src);
 378     Node *start_mem_dest = mm->memory_at(alias_idx_dest);
 379     Node* mem = start_mem_dest;
 380     bool same_alias = (alias_idx_src == alias_idx_dest);
 381 
 382     if (count > 0) {
 383       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 384       Node* v = LoadNode::make(*phase, forward_ctl, start_mem_src, adr_src, atp_src, value_type, copy_type, MemNode::unordered);
 385       v = phase->transform(v);
 386       if (copy_type == T_OBJECT) {
 387         v = bs->array_copy_load_store_barrier(phase, can_reshape, v, mm, forward_ctl);
 388       }
 389       mem = StoreNode::make(*phase, forward_ctl, mem, adr_dest, atp_dest, v, copy_type, MemNode::unordered);
 390       mem = phase->transform(mem);
 391       for (int i = 1; i < count; i++) {
 392         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 393         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 394         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 395         v = LoadNode::make(*phase, forward_ctl, same_alias ? mem : start_mem_src, next_src, atp_src, value_type, copy_type, MemNode::unordered);
 396         v = phase->transform(v);
 397         if (copy_type == T_OBJECT) {
 398           v = bs->array_copy_load_store_barrier(phase, can_reshape, v, mm, forward_ctl);
 399         }
 400         mem = StoreNode::make(*phase, forward_ctl,mem,next_dest,atp_dest,v, copy_type, MemNode::unordered);
 401         mem = phase->transform(mem);
 402       }
 403       mm->set_memory_at(alias_idx_dest, mem);
 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                                          MergeMemNode* mm,
 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     mm = mm->clone()->as_MergeMem();
 430     uint alias_idx_src = phase->C->get_alias_index(atp_src);
 431     uint alias_idx_dest = phase->C->get_alias_index(atp_dest);
 432     Node *start_mem_src = mm->memory_at(alias_idx_src);
 433     Node *start_mem_dest = mm->memory_at(alias_idx_dest);
 434     Node* mem = start_mem_dest;
 435 
 436     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 437     assert(copy_type != T_OBJECT || !bs->array_copy_requires_gc_barriers(false, T_OBJECT, false, BarrierSetC2::Optimization), "only tightly coupled allocations for object arrays");
 438     bool same_alias = (alias_idx_src == alias_idx_dest);
 439 
 440     if (count > 0) {
 441       for (int i = count-1; i >= 1; i--) {
 442         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 443         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 444         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 445         Node* v = LoadNode::make(*phase, backward_ctl, same_alias ? mem : start_mem_src, next_src, atp_src, value_type, copy_type, MemNode::unordered);
 446         v = phase->transform(v);
 447         if (copy_type == T_OBJECT) {
 448           v = bs->array_copy_load_store_barrier(phase, can_reshape, v, mm, backward_ctl);
 449         }
 450         mem = StoreNode::make(*phase, backward_ctl,mem,next_dest,atp_dest,v, copy_type, MemNode::unordered);
 451         mem = phase->transform(mem);
 452       }
 453       Node* v = LoadNode::make(*phase, backward_ctl, same_alias ? mem : start_mem_src, adr_src, atp_src, value_type, copy_type, MemNode::unordered);
 454       v = phase->transform(v);
 455       if (copy_type == T_OBJECT) {
 456         v = bs->array_copy_load_store_barrier(phase, can_reshape, v, mm, backward_ctl);
 457       }
 458       mem = StoreNode::make(*phase, backward_ctl, mem, adr_dest, atp_dest, v, copy_type, MemNode::unordered);
 459       mem = phase->transform(mem);
 460       mm->set_memory_at(alias_idx_dest, mem);
 461     } else if(can_reshape) {
 462       PhaseIterGVN* igvn = phase->is_IterGVN();
 463       igvn->_worklist.push(adr_src);
 464       igvn->_worklist.push(adr_dest);
 465     }
 466     return phase->transform(mm);
 467   }
 468   return phase->C->top();
 469 }
 470 
 471 bool ArrayCopyNode::finish_transform(PhaseGVN *phase, bool can_reshape,
 472                                      Node* ctl, Node *mem) {
 473   if (can_reshape) {
 474     PhaseIterGVN* igvn = phase->is_IterGVN();
 475     igvn->set_delay_transform(false);
 476     if (is_clonebasic()) {
 477       Node* out_mem = proj_out(TypeFunc::Memory);
 478 
 479       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 480       if (out_mem->outcnt() != 1 || !out_mem->raw_out(0)->is_MergeMem() ||
 481           out_mem->raw_out(0)->outcnt() != 1 || !out_mem->raw_out(0)->raw_out(0)->is_MemBar()) {
 482         assert(bs->array_copy_requires_gc_barriers(true, T_OBJECT, true, BarrierSetC2::Optimization), "can only happen with card marking");
 483         return false;
 484       }
 485 
 486       igvn->replace_node(out_mem->raw_out(0), mem);
 487 
 488       Node* out_ctl = proj_out(TypeFunc::Control);
 489       igvn->replace_node(out_ctl, ctl);
 490     } else {
 491       // replace fallthrough projections of the ArrayCopyNode by the
 492       // new memory, control and the input IO.
 493       CallProjections callprojs;
 494       extract_projections(&callprojs, true, false);
 495 
 496       if (callprojs.fallthrough_ioproj != NULL) {
 497         igvn->replace_node(callprojs.fallthrough_ioproj, in(TypeFunc::I_O));
 498       }
 499       if (callprojs.fallthrough_memproj != NULL) {
 500         igvn->replace_node(callprojs.fallthrough_memproj, mem);
 501       }
 502       if (callprojs.fallthrough_catchproj != NULL) {
 503         igvn->replace_node(callprojs.fallthrough_catchproj, ctl);
 504       }
 505 
 506       // The ArrayCopyNode is not disconnected. It still has the
 507       // projections for the exception case. Replace current
 508       // ArrayCopyNode with a dummy new one with a top() control so
 509       // that this part of the graph stays consistent but is
 510       // eventually removed.
 511 
 512       set_req(0, phase->C->top());
 513       remove_dead_region(phase, can_reshape);
 514     }
 515   } else {
 516     if (in(TypeFunc::Control) != ctl) {
 517       // we can't return new memory and control from Ideal at parse time
 518       assert(!is_clonebasic(), "added control for clone?");
 519       phase->record_for_igvn(this);
 520       return false;
 521     }
 522   }
 523   return true;
 524 }
 525 
 526 
 527 Node *ArrayCopyNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 528   if (remove_dead_region(phase, can_reshape))  return this;
 529 
 530   if (StressArrayCopyMacroNode && !can_reshape) {
 531     phase->record_for_igvn(this);
 532     return NULL;
 533   }
 534 
 535   // See if it's a small array copy and we can inline it as
 536   // loads/stores
 537   // Here we can only do:
 538   // - arraycopy if all arguments were validated before and we don't
 539   // need card marking
 540   // - clone for which we don't need to do card marking
 541 
 542   if (!is_clonebasic() && !is_arraycopy_validated() &&
 543       !is_copyofrange_validated() && !is_copyof_validated()) {
 544     return NULL;
 545   }
 546 
 547   assert(in(TypeFunc::Control) != NULL &&
 548          in(TypeFunc::Memory) != NULL &&
 549          in(ArrayCopyNode::Src) != NULL &&
 550          in(ArrayCopyNode::Dest) != NULL &&
 551          in(ArrayCopyNode::Length) != NULL &&
 552          ((in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::DestPos) != NULL) ||
 553           is_clonebasic()), "broken inputs");
 554 
 555   if (in(TypeFunc::Control)->is_top() ||
 556       in(TypeFunc::Memory)->is_top() ||
 557       phase->type(in(ArrayCopyNode::Src)) == Type::TOP ||
 558       phase->type(in(ArrayCopyNode::Dest)) == Type::TOP ||
 559       (in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::SrcPos)->is_top()) ||
 560       (in(ArrayCopyNode::DestPos) != NULL && in(ArrayCopyNode::DestPos)->is_top())) {
 561     return NULL;
 562   }
 563 
 564   int count = get_count(phase);
 565 
 566   if (count < 0 || count > ArrayCopyLoadStoreMaxElem) {
 567     return NULL;
 568   }
 569 
 570   Node* mem = try_clone_instance(phase, can_reshape, count);
 571   if (mem != NULL) {
 572     return (mem == NodeSentinel) ? NULL : mem;
 573   }
 574 
 575   Node* adr_src = NULL;
 576   Node* base_src = NULL;
 577   Node* adr_dest = NULL;
 578   Node* base_dest = NULL;
 579   BasicType copy_type = T_ILLEGAL;
 580   const Type* value_type = NULL;
 581   bool disjoint_bases = false;
 582 
 583   if (!prepare_array_copy(phase, can_reshape,
 584                           adr_src, base_src, adr_dest, base_dest,
 585                           copy_type, value_type, disjoint_bases)) {
 586     return NULL;
 587   }
 588 
 589   Node* src = in(ArrayCopyNode::Src);
 590   Node* dest = in(ArrayCopyNode::Dest);
 591   const TypePtr* atp_src = get_address_type(phase, src);
 592   const TypePtr* atp_dest = get_address_type(phase, dest);
 593 
 594   Node *in_mem = in(TypeFunc::Memory);
 595   if (!in_mem->is_MergeMem()) {
 596     in_mem = MergeMemNode::make(in_mem);
 597   }
 598 
 599 
 600   if (can_reshape) {
 601     assert(!phase->is_IterGVN()->delay_transform(), "cannot delay transforms");
 602     phase->is_IterGVN()->set_delay_transform(true);
 603   }
 604 
 605   Node* backward_ctl = phase->C->top();
 606   Node* forward_ctl = phase->C->top();
 607   array_copy_test_overlap(phase, can_reshape, disjoint_bases, count, forward_ctl, backward_ctl);
 608 
 609   Node* forward_mem = array_copy_forward(phase, can_reshape, forward_ctl,
 610                                          in_mem->as_MergeMem(),
 611                                          atp_src, atp_dest,
 612                                          adr_src, base_src, adr_dest, base_dest,
 613                                          copy_type, value_type, count);
 614 
 615   Node* backward_mem = array_copy_backward(phase, can_reshape, backward_ctl,
 616                                            in_mem->as_MergeMem(),
 617                                            atp_src, atp_dest,
 618                                            adr_src, base_src, adr_dest, base_dest,
 619                                            copy_type, value_type, count);
 620 
 621   Node* ctl = NULL;
 622   if (!forward_ctl->is_top() && !backward_ctl->is_top()) {
 623     ctl = new RegionNode(3);
 624     ctl->init_req(1, forward_ctl);
 625     ctl->init_req(2, backward_ctl);
 626     ctl = phase->transform(ctl);
 627     MergeMemNode* forward_mm = forward_mem->as_MergeMem();
 628     MergeMemNode* backward_mm = backward_mem->as_MergeMem();
 629     for (MergeMemStream mms(forward_mm, backward_mm); mms.next_non_empty2(); ) {
 630       if (mms.memory() != mms.memory2()) {
 631         Node* phi = new PhiNode(ctl, Type::MEMORY, phase->C->get_adr_type(mms.alias_idx()));
 632         phi->init_req(1, mms.memory());
 633         phi->init_req(2, mms.memory2());
 634         phi = phase->transform(phi);
 635         mms.set_memory(phi);
 636       }
 637     }
 638     mem = forward_mem;
 639   } else if (!forward_ctl->is_top()) {
 640     ctl = forward_ctl;
 641     mem = forward_mem;
 642   } else {
 643     assert(!backward_ctl->is_top(), "no copy?");
 644     ctl = backward_ctl;
 645     mem = backward_mem;
 646   }
 647 
 648   if (can_reshape) {
 649     assert(phase->is_IterGVN()->delay_transform(), "should be delaying transforms");
 650     phase->is_IterGVN()->set_delay_transform(false);
 651   }
 652 
 653   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 654     return NULL;
 655   }
 656 
 657   return mem;
 658 }
 659 
 660 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 661   Node* dest = in(ArrayCopyNode::Dest);
 662   if (dest->is_top()) {
 663     return false;
 664   }
 665   const TypeOopPtr* dest_t = phase->type(dest)->is_oopptr();
 666   assert(!dest_t->is_known_instance() || _dest_type->is_known_instance(), "result of EA not recorded");
 667   assert(in(ArrayCopyNode::Src)->is_top() || !phase->type(in(ArrayCopyNode::Src))->is_oopptr()->is_known_instance() ||
 668          _src_type->is_known_instance(), "result of EA not recorded");
 669 
 670   if (_dest_type != TypeOopPtr::BOTTOM || t_oop->is_known_instance()) {
 671     assert(_dest_type == TypeOopPtr::BOTTOM || _dest_type->is_known_instance(), "result of EA is known instance");
 672     return t_oop->instance_id() == _dest_type->instance_id();
 673   }
 674 
 675   return CallNode::may_modify_arraycopy_helper(dest_t, t_oop, phase);
 676 }
 677 
 678 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr *t_oop, Node* n, PhaseTransform *phase, CallNode*& call) {
 679   if (n != NULL &&
 680       n->is_Call() &&
 681       n->as_Call()->may_modify(t_oop, phase) &&
 682       (n->as_Call()->is_ArrayCopy() || n->as_Call()->is_call_to_arraycopystub())) {
 683     call = n->as_Call();
 684     return true;
 685   }
 686   return false;
 687 }
 688 
 689 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, MemBarNode* mb, PhaseTransform *phase, ArrayCopyNode*& ac) {
 690 
 691   Node* c = mb->in(0);
 692 
 693   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 694   // step over g1 gc barrier if we're at e.g. a clone with ReduceInitialCardMarks off
 695   c = bs->step_over_gc_barrier(c);
 696 
 697   CallNode* call = NULL;
 698   guarantee(c != NULL, "step_over_gc_barrier failed, there must be something to step to.");
 699   if (c->is_Region()) {
 700     for (uint i = 1; i < c->req(); i++) {
 701       if (c->in(i) != NULL) {
 702         Node* n = c->in(i)->in(0);
 703         if (may_modify_helper(t_oop, n, phase, call)) {
 704           ac = call->isa_ArrayCopy();
 705           assert(c == mb->in(0), "only for clone");
 706           return true;
 707         }
 708       }
 709     }
 710   } else if (may_modify_helper(t_oop, c->in(0), phase, call)) {
 711     ac = call->isa_ArrayCopy();
 712 #ifdef ASSERT
 713     bool use_ReduceInitialCardMarks = BarrierSet::barrier_set()->is_a(BarrierSet::CardTableBarrierSet) &&
 714       static_cast<CardTableBarrierSetC2*>(bs)->use_ReduceInitialCardMarks();
 715     assert(c == mb->in(0) || (ac != NULL && ac->is_clonebasic() && !use_ReduceInitialCardMarks), "only for clone");
 716 #endif
 717     return true;
 718   }
 719 
 720   return false;
 721 }
 722 
 723 // Does this array copy modify offsets between offset_lo and offset_hi
 724 // in the destination array
 725 // if must_modify is false, return true if the copy could write
 726 // between offset_lo and offset_hi
 727 // if must_modify is true, return true if the copy is guaranteed to
 728 // write between offset_lo and offset_hi
 729 bool ArrayCopyNode::modifies(intptr_t offset_lo, intptr_t offset_hi, PhaseTransform* phase, bool must_modify) const {
 730   assert(_kind == ArrayCopy || _kind == CopyOf || _kind == CopyOfRange, "only for real array copies");
 731 
 732   Node* dest = in(Dest);
 733   Node* dest_pos = in(DestPos);
 734   Node* len = in(Length);
 735 
 736   const TypeInt *dest_pos_t = phase->type(dest_pos)->isa_int();
 737   const TypeInt *len_t = phase->type(len)->isa_int();
 738   const TypeAryPtr* ary_t = phase->type(dest)->isa_aryptr();
 739 
 740   if (dest_pos_t == NULL || len_t == NULL || ary_t == NULL) {
 741     return !must_modify;
 742   }
 743 
 744   BasicType ary_elem = ary_t->klass()->as_array_klass()->element_type()->basic_type();
 745   uint header = arrayOopDesc::base_offset_in_bytes(ary_elem);
 746   uint elemsize = type2aelembytes(ary_elem);
 747 
 748   jlong dest_pos_plus_len_lo = (((jlong)dest_pos_t->_lo) + len_t->_lo) * elemsize + header;
 749   jlong dest_pos_plus_len_hi = (((jlong)dest_pos_t->_hi) + len_t->_hi) * elemsize + header;
 750   jlong dest_pos_lo = ((jlong)dest_pos_t->_lo) * elemsize + header;
 751   jlong dest_pos_hi = ((jlong)dest_pos_t->_hi) * elemsize + header;
 752 
 753   if (must_modify) {
 754     if (offset_lo >= dest_pos_hi && offset_hi < dest_pos_plus_len_lo) {
 755       return true;
 756     }
 757   } else {
 758     if (offset_hi >= dest_pos_lo && offset_lo < dest_pos_plus_len_hi) {
 759       return true;
 760     }
 761   }
 762   return false;
 763 }