1 /*
   2  * Copyright (c) 2016, 2019, 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::load(BarrierSetC2* bs, PhaseGVN *phase, Node*& ctl, MergeMemNode* mem, Node* adr, const TypePtr* adr_type, const Type *type, BasicType bt) {
 152   DecoratorSet decorators = C2_READ_ACCESS | C2_CONTROL_DEPENDENT_LOAD | IN_HEAP | C2_ARRAY_COPY;
 153   C2AccessValuePtr addr(adr, adr_type);
 154   C2OptAccess access(*phase, ctl, mem, decorators, bt, adr->in(AddPNode::Base), addr);
 155   Node* res = bs->load_at(access, type);
 156   ctl = access.ctl();
 157   return res;
 158 }
 159 
 160 void ArrayCopyNode::store(BarrierSetC2* bs, PhaseGVN *phase, Node*& ctl, MergeMemNode* mem, Node* adr, const TypePtr* adr_type, Node* val, const Type *type, BasicType bt) {
 161   DecoratorSet decorators = C2_WRITE_ACCESS | IN_HEAP | C2_ARRAY_COPY;
 162   if (is_alloc_tightly_coupled()) {
 163     decorators |= C2_TIGHTLY_COUPLED_ALLOC;
 164   }
 165   C2AccessValuePtr addr(adr, adr_type);
 166   C2AccessValue value(val, type);
 167   C2OptAccess access(*phase, ctl, mem, decorators, bt, adr->in(AddPNode::Base), addr);
 168   bs->store_at(access, value);
 169   ctl = access.ctl();
 170 }
 171 
 172 
 173 Node* ArrayCopyNode::try_clone_instance(PhaseGVN *phase, bool can_reshape, int count) {
 174   if (!is_clonebasic()) {
 175     return NULL;
 176   }
 177 
 178   Node* src = in(ArrayCopyNode::Src);
 179   Node* dest = in(ArrayCopyNode::Dest);
 180   Node* ctl = in(TypeFunc::Control);
 181   Node* in_mem = in(TypeFunc::Memory);
 182 
 183   const Type* src_type = phase->type(src);
 184 
 185   assert(src->is_AddP(), "should be base + off");
 186   assert(dest->is_AddP(), "should be base + off");
 187   Node* base_src = src->in(AddPNode::Base);
 188   Node* base_dest = dest->in(AddPNode::Base);
 189 
 190   MergeMemNode* mem = MergeMemNode::make(in_mem);
 191 
 192   const TypeInstPtr* inst_src = src_type->isa_instptr();
 193 
 194   if (inst_src == NULL) {
 195     return NULL;
 196   }
 197 
 198   if (!inst_src->klass_is_exact()) {
 199     ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 200     assert(!ik->is_interface() && !ik->has_subklass(), "inconsistent klass hierarchy");
 201     phase->C->dependencies()->assert_leaf_type(ik);
 202   }
 203 
 204   ciInstanceKlass* ik = inst_src->klass()->as_instance_klass();
 205   assert(ik->nof_nonstatic_fields() <= ArrayCopyLoadStoreMaxElem, "too many fields");
 206 
 207   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 208   for (int i = 0; i < count; i++) {
 209     ciField* field = ik->nonstatic_field_at(i);
 210     int fieldidx = phase->C->alias_type(field)->index();
 211     const TypePtr* adr_type = phase->C->alias_type(field)->adr_type();
 212     Node* off = phase->MakeConX(field->offset());
 213     Node* next_src = phase->transform(new AddPNode(base_src,base_src,off));
 214     Node* next_dest = phase->transform(new AddPNode(base_dest,base_dest,off));
 215     BasicType bt = field->layout_type();
 216 
 217     const Type *type;
 218     if (bt == T_OBJECT) {
 219       if (!field->type()->is_loaded()) {
 220         type = TypeInstPtr::BOTTOM;
 221       } else {
 222         ciType* field_klass = field->type();
 223         type = TypeOopPtr::make_from_klass(field_klass->as_klass());
 224       }
 225     } else {
 226       type = Type::get_const_basic_type(bt);
 227     }
 228 
 229     Node* v = load(bs, phase, ctl, mem, next_src, adr_type, type, bt);
 230     store(bs, phase, ctl, mem, next_dest, adr_type, v, type, bt);
 231   }
 232 
 233   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 234     // Return NodeSentinel to indicate that the transform failed
 235     return NodeSentinel;
 236   }
 237 
 238   return mem;
 239 }
 240 
 241 bool ArrayCopyNode::prepare_array_copy(PhaseGVN *phase, bool can_reshape,
 242                                        Node*& adr_src,
 243                                        Node*& base_src,
 244                                        Node*& adr_dest,
 245                                        Node*& base_dest,
 246                                        BasicType& copy_type,
 247                                        const Type*& value_type,
 248                                        bool& disjoint_bases) {
 249   Node* src = in(ArrayCopyNode::Src);
 250   Node* dest = in(ArrayCopyNode::Dest);
 251   const Type* src_type = phase->type(src);
 252   const TypeAryPtr* ary_src = src_type->isa_aryptr();
 253 
 254   if (is_arraycopy() || is_copyofrange() || is_copyof()) {
 255     const Type* dest_type = phase->type(dest);
 256     const TypeAryPtr* ary_dest = dest_type->isa_aryptr();
 257     Node* src_offset = in(ArrayCopyNode::SrcPos);
 258     Node* dest_offset = in(ArrayCopyNode::DestPos);
 259 
 260     // newly allocated object is guaranteed to not overlap with source object
 261     disjoint_bases = is_alloc_tightly_coupled();
 262 
 263     if (ary_src  == NULL || ary_src->klass()  == NULL ||
 264         ary_dest == NULL || ary_dest->klass() == NULL) {
 265       // We don't know if arguments are arrays
 266       return false;
 267     }
 268 
 269     BasicType src_elem  = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 270     BasicType dest_elem = ary_dest->klass()->as_array_klass()->element_type()->basic_type();
 271     if (src_elem  == T_ARRAY)  src_elem  = T_OBJECT;
 272     if (dest_elem == T_ARRAY)  dest_elem = T_OBJECT;
 273 
 274     if (src_elem != dest_elem || dest_elem == T_VOID) {
 275       // We don't know if arguments are arrays of the same type
 276       return false;
 277     }
 278 
 279     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 280     if (bs->array_copy_requires_gc_barriers(is_alloc_tightly_coupled(), dest_elem, false, BarrierSetC2::Optimization)) {
 281       // It's an object array copy but we can't emit the card marking
 282       // that is needed
 283       return false;
 284     }
 285 
 286     value_type = ary_src->elem();
 287 
 288     base_src = src;
 289     base_dest = dest;
 290 
 291     uint shift  = exact_log2(type2aelembytes(dest_elem));
 292     uint header = arrayOopDesc::base_offset_in_bytes(dest_elem);
 293 
 294     adr_src = src;
 295     adr_dest = dest;
 296 
 297     src_offset = Compile::conv_I2X_index(phase, src_offset, ary_src->size());
 298     dest_offset = Compile::conv_I2X_index(phase, dest_offset, ary_dest->size());
 299     if (src_offset->is_top() || dest_offset->is_top()) {
 300       // Offset is out of bounds (the ArrayCopyNode will be removed)
 301       return false;
 302     }
 303 
 304     Node* src_scale = phase->transform(new LShiftXNode(src_offset, phase->intcon(shift)));
 305     Node* dest_scale = phase->transform(new LShiftXNode(dest_offset, phase->intcon(shift)));
 306 
 307     adr_src = phase->transform(new AddPNode(base_src, adr_src, src_scale));
 308     adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, dest_scale));
 309 
 310     adr_src = new AddPNode(base_src, adr_src, phase->MakeConX(header));
 311     adr_dest = new AddPNode(base_dest, adr_dest, phase->MakeConX(header));
 312 
 313     adr_src = phase->transform(adr_src);
 314     adr_dest = phase->transform(adr_dest);
 315 
 316     copy_type = dest_elem;
 317   } else {
 318     assert(ary_src != NULL, "should be a clone");
 319     assert(is_clonebasic(), "should be");
 320 
 321     disjoint_bases = true;
 322     assert(src->is_AddP(), "should be base + off");
 323     assert(dest->is_AddP(), "should be base + off");
 324     adr_src = src;
 325     base_src = src->in(AddPNode::Base);
 326     adr_dest = dest;
 327     base_dest = dest->in(AddPNode::Base);
 328 
 329     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?");
 330     BasicType elem = ary_src->klass()->as_array_klass()->element_type()->basic_type();
 331     if (elem == T_ARRAY)  elem = T_OBJECT;
 332 
 333     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 334     if (bs->array_copy_requires_gc_barriers(true, elem, true, BarrierSetC2::Optimization)) {
 335       return false;
 336     }
 337 
 338     int diff = arrayOopDesc::base_offset_in_bytes(elem) - phase->type(src->in(AddPNode::Offset))->is_intptr_t()->get_con();
 339     assert(diff >= 0, "clone should not start after 1st array element");
 340     if (diff > 0) {
 341       adr_src = phase->transform(new AddPNode(base_src, adr_src, phase->MakeConX(diff)));
 342       adr_dest = phase->transform(new AddPNode(base_dest, adr_dest, phase->MakeConX(diff)));
 343     }
 344 
 345     copy_type = elem;
 346     value_type = ary_src->elem();
 347   }
 348   return true;
 349 }
 350 
 351 const TypePtr* ArrayCopyNode::get_address_type(PhaseGVN *phase, Node* n) {
 352   const Type* at = phase->type(n);
 353   assert(at != Type::TOP, "unexpected type");
 354   const TypePtr* atp = at->isa_ptr();
 355   // adjust atp to be the correct array element address type
 356   atp = atp->add_offset(Type::OffsetBot);
 357   return atp;
 358 }
 359 
 360 void ArrayCopyNode::array_copy_test_overlap(PhaseGVN *phase, bool can_reshape, bool disjoint_bases, int count, Node*& forward_ctl, Node*& backward_ctl) {
 361   Node* ctl = in(TypeFunc::Control);
 362   if (!disjoint_bases && count > 1) {
 363     Node* src_offset = in(ArrayCopyNode::SrcPos);
 364     Node* dest_offset = in(ArrayCopyNode::DestPos);
 365     assert(src_offset != NULL && dest_offset != NULL, "should be");
 366     Node* cmp = phase->transform(new CmpINode(src_offset, dest_offset));
 367     Node *bol = phase->transform(new BoolNode(cmp, BoolTest::lt));
 368     IfNode *iff = new IfNode(ctl, bol, PROB_FAIR, COUNT_UNKNOWN);
 369 
 370     phase->transform(iff);
 371 
 372     forward_ctl = phase->transform(new IfFalseNode(iff));
 373     backward_ctl = phase->transform(new IfTrueNode(iff));
 374   } else {
 375     forward_ctl = ctl;
 376   }
 377 }
 378 
 379 Node* ArrayCopyNode::array_copy_forward(PhaseGVN *phase,
 380                                         bool can_reshape,
 381                                         Node*& forward_ctl,
 382                                         MergeMemNode* mm,
 383                                         const TypePtr* atp_src,
 384                                         const TypePtr* atp_dest,
 385                                         Node* adr_src,
 386                                         Node* base_src,
 387                                         Node* adr_dest,
 388                                         Node* base_dest,
 389                                         BasicType copy_type,
 390                                         const Type* value_type,
 391                                         int count) {
 392   if (!forward_ctl->is_top()) {
 393     // copy forward
 394     mm = mm->clone()->as_MergeMem();
 395 
 396     if (count > 0) {
 397       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 398       Node* v = load(bs, phase, forward_ctl, mm, adr_src, atp_src, value_type, copy_type);
 399       store(bs, phase, forward_ctl, mm, adr_dest, atp_dest, v, value_type, copy_type);
 400       for (int i = 1; i < count; i++) {
 401         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 402         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 403         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 404         v = load(bs, phase, forward_ctl, mm, next_src, atp_src, value_type, copy_type);
 405         store(bs, phase, forward_ctl, mm, next_dest, atp_dest, v, value_type, copy_type);
 406       }
 407     } else if(can_reshape) {
 408       PhaseIterGVN* igvn = phase->is_IterGVN();
 409       igvn->_worklist.push(adr_src);
 410       igvn->_worklist.push(adr_dest);
 411     }
 412     return mm;
 413   }
 414   return phase->C->top();
 415 }
 416 
 417 Node* ArrayCopyNode::array_copy_backward(PhaseGVN *phase,
 418                                          bool can_reshape,
 419                                          Node*& backward_ctl,
 420                                          MergeMemNode* mm,
 421                                          const TypePtr* atp_src,
 422                                          const TypePtr* atp_dest,
 423                                          Node* adr_src,
 424                                          Node* base_src,
 425                                          Node* adr_dest,
 426                                          Node* base_dest,
 427                                          BasicType copy_type,
 428                                          const Type* value_type,
 429                                          int count) {
 430   if (!backward_ctl->is_top()) {
 431     // copy backward
 432     mm = mm->clone()->as_MergeMem();
 433 
 434     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 435     assert(copy_type != T_OBJECT || !bs->array_copy_requires_gc_barriers(false, T_OBJECT, false, BarrierSetC2::Optimization), "only tightly coupled allocations for object arrays");
 436 
 437     if (count > 0) {
 438       for (int i = count-1; i >= 1; i--) {
 439         Node* off  = phase->MakeConX(type2aelembytes(copy_type) * i);
 440         Node* next_src = phase->transform(new AddPNode(base_src,adr_src,off));
 441         Node* next_dest = phase->transform(new AddPNode(base_dest,adr_dest,off));
 442         Node* v = load(bs, phase, backward_ctl, mm, next_src, atp_src, value_type, copy_type);
 443         store(bs, phase, backward_ctl, mm, next_dest, atp_dest, v, value_type, copy_type);
 444       }
 445       Node* v = load(bs, phase, backward_ctl, mm, adr_src, atp_src, value_type, copy_type);
 446       store(bs, phase, backward_ctl, mm, adr_dest, atp_dest, v, value_type, copy_type);
 447     } else if(can_reshape) {
 448       PhaseIterGVN* igvn = phase->is_IterGVN();
 449       igvn->_worklist.push(adr_src);
 450       igvn->_worklist.push(adr_dest);
 451     }
 452     return phase->transform(mm);
 453   }
 454   return phase->C->top();
 455 }
 456 
 457 bool ArrayCopyNode::finish_transform(PhaseGVN *phase, bool can_reshape,
 458                                      Node* ctl, Node *mem) {
 459   if (can_reshape) {
 460     PhaseIterGVN* igvn = phase->is_IterGVN();
 461     igvn->set_delay_transform(false);
 462     if (is_clonebasic()) {
 463       Node* out_mem = proj_out(TypeFunc::Memory);
 464 
 465       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 466       if (out_mem->outcnt() != 1 || !out_mem->raw_out(0)->is_MergeMem() ||
 467           out_mem->raw_out(0)->outcnt() != 1 || !out_mem->raw_out(0)->raw_out(0)->is_MemBar()) {
 468         assert(bs->array_copy_requires_gc_barriers(true, T_OBJECT, true, BarrierSetC2::Optimization), "can only happen with card marking");
 469         return false;
 470       }
 471 
 472       igvn->replace_node(out_mem->raw_out(0), mem);
 473 
 474       Node* out_ctl = proj_out(TypeFunc::Control);
 475       igvn->replace_node(out_ctl, ctl);
 476     } else {
 477       // replace fallthrough projections of the ArrayCopyNode by the
 478       // new memory, control and the input IO.
 479       CallProjections callprojs;
 480       extract_projections(&callprojs, true, false);
 481 
 482       if (callprojs.fallthrough_ioproj != NULL) {
 483         igvn->replace_node(callprojs.fallthrough_ioproj, in(TypeFunc::I_O));
 484       }
 485       if (callprojs.fallthrough_memproj != NULL) {
 486         igvn->replace_node(callprojs.fallthrough_memproj, mem);
 487       }
 488       if (callprojs.fallthrough_catchproj != NULL) {
 489         igvn->replace_node(callprojs.fallthrough_catchproj, ctl);
 490       }
 491 
 492       // The ArrayCopyNode is not disconnected. It still has the
 493       // projections for the exception case. Replace current
 494       // ArrayCopyNode with a dummy new one with a top() control so
 495       // that this part of the graph stays consistent but is
 496       // eventually removed.
 497 
 498       set_req(0, phase->C->top());
 499       remove_dead_region(phase, can_reshape);
 500     }
 501   } else {
 502     if (in(TypeFunc::Control) != ctl) {
 503       // we can't return new memory and control from Ideal at parse time
 504       assert(!is_clonebasic() || UseShenandoahGC, "added control for clone?");
 505       phase->record_for_igvn(this);
 506       return false;
 507     }
 508   }
 509   return true;
 510 }
 511 
 512 
 513 Node *ArrayCopyNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 514   if (remove_dead_region(phase, can_reshape))  return this;
 515 
 516   if (StressArrayCopyMacroNode && !can_reshape) {
 517     phase->record_for_igvn(this);
 518     return NULL;
 519   }
 520 
 521   // See if it's a small array copy and we can inline it as
 522   // loads/stores
 523   // Here we can only do:
 524   // - arraycopy if all arguments were validated before and we don't
 525   // need card marking
 526   // - clone for which we don't need to do card marking
 527 
 528   if (!is_clonebasic() && !is_arraycopy_validated() &&
 529       !is_copyofrange_validated() && !is_copyof_validated()) {
 530     return NULL;
 531   }
 532 
 533   assert(in(TypeFunc::Control) != NULL &&
 534          in(TypeFunc::Memory) != NULL &&
 535          in(ArrayCopyNode::Src) != NULL &&
 536          in(ArrayCopyNode::Dest) != NULL &&
 537          in(ArrayCopyNode::Length) != NULL &&
 538          ((in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::DestPos) != NULL) ||
 539           is_clonebasic()), "broken inputs");
 540 
 541   if (in(TypeFunc::Control)->is_top() ||
 542       in(TypeFunc::Memory)->is_top() ||
 543       phase->type(in(ArrayCopyNode::Src)) == Type::TOP ||
 544       phase->type(in(ArrayCopyNode::Dest)) == Type::TOP ||
 545       (in(ArrayCopyNode::SrcPos) != NULL && in(ArrayCopyNode::SrcPos)->is_top()) ||
 546       (in(ArrayCopyNode::DestPos) != NULL && in(ArrayCopyNode::DestPos)->is_top())) {
 547     return NULL;
 548   }
 549 
 550   int count = get_count(phase);
 551 
 552   if (count < 0 || count > ArrayCopyLoadStoreMaxElem) {
 553     return NULL;
 554   }
 555 
 556   Node* mem = try_clone_instance(phase, can_reshape, count);
 557   if (mem != NULL) {
 558     return (mem == NodeSentinel) ? NULL : mem;
 559   }
 560 
 561   Node* adr_src = NULL;
 562   Node* base_src = NULL;
 563   Node* adr_dest = NULL;
 564   Node* base_dest = NULL;
 565   BasicType copy_type = T_ILLEGAL;
 566   const Type* value_type = NULL;
 567   bool disjoint_bases = false;
 568 
 569   if (!prepare_array_copy(phase, can_reshape,
 570                           adr_src, base_src, adr_dest, base_dest,
 571                           copy_type, value_type, disjoint_bases)) {
 572     return NULL;
 573   }
 574 
 575   Node* src = in(ArrayCopyNode::Src);
 576   Node* dest = in(ArrayCopyNode::Dest);
 577   const TypePtr* atp_src = get_address_type(phase, src);
 578   const TypePtr* atp_dest = get_address_type(phase, dest);
 579 
 580   Node *in_mem = in(TypeFunc::Memory);
 581   if (!in_mem->is_MergeMem()) {
 582     in_mem = MergeMemNode::make(in_mem);
 583   }
 584 
 585 
 586   if (can_reshape) {
 587     assert(!phase->is_IterGVN()->delay_transform(), "cannot delay transforms");
 588     phase->is_IterGVN()->set_delay_transform(true);
 589   }
 590 
 591   Node* backward_ctl = phase->C->top();
 592   Node* forward_ctl = phase->C->top();
 593   array_copy_test_overlap(phase, can_reshape, disjoint_bases, count, forward_ctl, backward_ctl);
 594 
 595   Node* forward_mem = array_copy_forward(phase, can_reshape, forward_ctl,
 596                                          in_mem->as_MergeMem(),
 597                                          atp_src, atp_dest,
 598                                          adr_src, base_src, adr_dest, base_dest,
 599                                          copy_type, value_type, count);
 600 
 601   Node* backward_mem = array_copy_backward(phase, can_reshape, backward_ctl,
 602                                            in_mem->as_MergeMem(),
 603                                            atp_src, atp_dest,
 604                                            adr_src, base_src, adr_dest, base_dest,
 605                                            copy_type, value_type, count);
 606 
 607   Node* ctl = NULL;
 608   if (!forward_ctl->is_top() && !backward_ctl->is_top()) {
 609     ctl = new RegionNode(3);
 610     ctl->init_req(1, forward_ctl);
 611     ctl->init_req(2, backward_ctl);
 612     ctl = phase->transform(ctl);
 613     MergeMemNode* forward_mm = forward_mem->as_MergeMem();
 614     MergeMemNode* backward_mm = backward_mem->as_MergeMem();
 615     for (MergeMemStream mms(forward_mm, backward_mm); mms.next_non_empty2(); ) {
 616       if (mms.memory() != mms.memory2()) {
 617         Node* phi = new PhiNode(ctl, Type::MEMORY, phase->C->get_adr_type(mms.alias_idx()));
 618         phi->init_req(1, mms.memory());
 619         phi->init_req(2, mms.memory2());
 620         phi = phase->transform(phi);
 621         mms.set_memory(phi);
 622       }
 623     }
 624     mem = forward_mem;
 625   } else if (!forward_ctl->is_top()) {
 626     ctl = forward_ctl;
 627     mem = forward_mem;
 628   } else {
 629     assert(!backward_ctl->is_top(), "no copy?");
 630     ctl = backward_ctl;
 631     mem = backward_mem;
 632   }
 633 
 634   if (can_reshape) {
 635     assert(phase->is_IterGVN()->delay_transform(), "should be delaying transforms");
 636     phase->is_IterGVN()->set_delay_transform(false);
 637   }
 638 
 639   if (!finish_transform(phase, can_reshape, ctl, mem)) {
 640     return NULL;
 641   }
 642 
 643   return mem;
 644 }
 645 
 646 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 647   Node* dest = in(ArrayCopyNode::Dest);
 648   if (dest->is_top()) {
 649     return false;
 650   }
 651   const TypeOopPtr* dest_t = phase->type(dest)->is_oopptr();
 652   assert(!dest_t->is_known_instance() || _dest_type->is_known_instance(), "result of EA not recorded");
 653   assert(in(ArrayCopyNode::Src)->is_top() || !phase->type(in(ArrayCopyNode::Src))->is_oopptr()->is_known_instance() ||
 654          _src_type->is_known_instance(), "result of EA not recorded");
 655 
 656   if (_dest_type != TypeOopPtr::BOTTOM || t_oop->is_known_instance()) {
 657     assert(_dest_type == TypeOopPtr::BOTTOM || _dest_type->is_known_instance(), "result of EA is known instance");
 658     return t_oop->instance_id() == _dest_type->instance_id();
 659   }
 660 
 661   return CallNode::may_modify_arraycopy_helper(dest_t, t_oop, phase);
 662 }
 663 
 664 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr *t_oop, Node* n, PhaseTransform *phase, CallNode*& call) {
 665   if (n != NULL &&
 666       n->is_Call() &&
 667       n->as_Call()->may_modify(t_oop, phase) &&
 668       (n->as_Call()->is_ArrayCopy() || n->as_Call()->is_call_to_arraycopystub())) {
 669     call = n->as_Call();
 670     return true;
 671   }
 672   return false;
 673 }
 674 
 675 bool ArrayCopyNode::may_modify(const TypeOopPtr *t_oop, MemBarNode* mb, PhaseTransform *phase, ArrayCopyNode*& ac) {
 676 
 677   Node* c = mb->in(0);
 678 
 679   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 680   // step over g1 gc barrier if we're at e.g. a clone with ReduceInitialCardMarks off
 681   c = bs->step_over_gc_barrier(c);
 682 
 683   CallNode* call = NULL;
 684   guarantee(c != NULL, "step_over_gc_barrier failed, there must be something to step to.");
 685   if (c->is_Region()) {
 686     for (uint i = 1; i < c->req(); i++) {
 687       if (c->in(i) != NULL) {
 688         Node* n = c->in(i)->in(0);
 689         if (may_modify_helper(t_oop, n, phase, call)) {
 690           ac = call->isa_ArrayCopy();
 691           assert(c == mb->in(0), "only for clone");
 692           return true;
 693         }
 694       }
 695     }
 696   } else if (may_modify_helper(t_oop, c->in(0), phase, call)) {
 697     ac = call->isa_ArrayCopy();
 698 #ifdef ASSERT
 699     bool use_ReduceInitialCardMarks = BarrierSet::barrier_set()->is_a(BarrierSet::CardTableBarrierSet) &&
 700       static_cast<CardTableBarrierSetC2*>(bs)->use_ReduceInitialCardMarks();
 701     assert(c == mb->in(0) || (ac != NULL && ac->is_clonebasic() && !use_ReduceInitialCardMarks), "only for clone");
 702 #endif
 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 }