1 /*
   2  * Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "gc/shared/collectedHeap.inline.hpp"
  28 #include "gc/shared/tlab_globals.hpp"
  29 #include "libadt/vectset.hpp"
  30 #include "memory/universe.hpp"
  31 #include "opto/addnode.hpp"
  32 #include "opto/arraycopynode.hpp"
  33 #include "opto/callnode.hpp"
  34 #include "opto/castnode.hpp"
  35 #include "opto/cfgnode.hpp"
  36 #include "opto/compile.hpp"
  37 #include "opto/convertnode.hpp"
  38 #include "opto/graphKit.hpp"
  39 #include "opto/intrinsicnode.hpp"
  40 #include "opto/locknode.hpp"
  41 #include "opto/loopnode.hpp"
  42 #include "opto/macro.hpp"
  43 #include "opto/memnode.hpp"
  44 #include "opto/narrowptrnode.hpp"
  45 #include "opto/node.hpp"
  46 #include "opto/opaquenode.hpp"
  47 #include "opto/phaseX.hpp"
  48 #include "opto/rootnode.hpp"
  49 #include "opto/runtime.hpp"
  50 #include "opto/subnode.hpp"
  51 #include "opto/subtypenode.hpp"
  52 #include "opto/type.hpp"
  53 #include "prims/jvmtiExport.hpp"
  54 #include "runtime/sharedRuntime.hpp"
  55 #include "utilities/macros.hpp"
  56 #include "utilities/powerOfTwo.hpp"
  57 #if INCLUDE_G1GC
  58 #include "gc/g1/g1ThreadLocalData.hpp"
  59 #endif // INCLUDE_G1GC
  60 #if INCLUDE_SHENANDOAHGC
  61 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
  62 #endif
  63 
  64 
  65 //
  66 // Replace any references to "oldref" in inputs to "use" with "newref".
  67 // Returns the number of replacements made.
  68 //
  69 int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
  70   int nreplacements = 0;
  71   uint req = use->req();
  72   for (uint j = 0; j < use->len(); j++) {
  73     Node *uin = use->in(j);
  74     if (uin == oldref) {
  75       if (j < req)
  76         use->set_req(j, newref);
  77       else
  78         use->set_prec(j, newref);
  79       nreplacements++;
  80     } else if (j >= req && uin == NULL) {
  81       break;
  82     }
  83   }
  84   return nreplacements;
  85 }
  86 
  87 void PhaseMacroExpand::migrate_outs(Node *old, Node *target) {
  88   assert(old != NULL, "sanity");
  89   for (DUIterator_Fast imax, i = old->fast_outs(imax); i < imax; i++) {
  90     Node* use = old->fast_out(i);
  91     _igvn.rehash_node_delayed(use);
  92     imax -= replace_input(use, old, target);
  93     // back up iterator
  94     --i;
  95   }
  96   assert(old->outcnt() == 0, "all uses must be deleted");
  97 }
  98 
  99 Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word, int mask, int bits, bool return_fast_path) {
 100   Node* cmp;
 101   if (mask != 0) {
 102     Node* and_node = transform_later(new AndXNode(word, MakeConX(mask)));
 103     cmp = transform_later(new CmpXNode(and_node, MakeConX(bits)));
 104   } else {
 105     cmp = word;
 106   }
 107   Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
 108   IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
 109   transform_later(iff);
 110 
 111   // Fast path taken.
 112   Node *fast_taken = transform_later(new IfFalseNode(iff));
 113 
 114   // Fast path not-taken, i.e. slow path
 115   Node *slow_taken = transform_later(new IfTrueNode(iff));
 116 
 117   if (return_fast_path) {
 118     region->init_req(edge, slow_taken); // Capture slow-control
 119     return fast_taken;
 120   } else {
 121     region->init_req(edge, fast_taken); // Capture fast-control
 122     return slow_taken;
 123   }
 124 }
 125 
 126 //--------------------copy_predefined_input_for_runtime_call--------------------
 127 void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
 128   // Set fixed predefined input arguments
 129   call->init_req( TypeFunc::Control, ctrl );
 130   call->init_req( TypeFunc::I_O    , oldcall->in( TypeFunc::I_O) );
 131   call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
 132   call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
 133   call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
 134 }
 135 
 136 //------------------------------make_slow_call---------------------------------
 137 CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
 138                                            address slow_call, const char* leaf_name, Node* slow_path,
 139                                            Node* parm0, Node* parm1, Node* parm2) {
 140 
 141   // Slow-path call
 142  CallNode *call = leaf_name
 143    ? (CallNode*)new CallLeafNode      ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
 144    : (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
 145 
 146   // Slow path call has no side-effects, uses few values
 147   copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
 148   if (parm0 != NULL)  call->init_req(TypeFunc::Parms+0, parm0);
 149   if (parm1 != NULL)  call->init_req(TypeFunc::Parms+1, parm1);
 150   if (parm2 != NULL)  call->init_req(TypeFunc::Parms+2, parm2);
 151   call->copy_call_debug_info(&_igvn, oldcall);
 152   call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
 153   _igvn.replace_node(oldcall, call);
 154   transform_later(call);
 155 
 156   return call;
 157 }
 158 
 159 void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
 160   BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 161   bs->eliminate_gc_barrier(this, p2x);
 162 }
 163 
 164 // Search for a memory operation for the specified memory slice.
 165 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
 166   Node *orig_mem = mem;
 167   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 168   const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
 169   while (true) {
 170     if (mem == alloc_mem || mem == start_mem ) {
 171       return mem;  // hit one of our sentinels
 172     } else if (mem->is_MergeMem()) {
 173       mem = mem->as_MergeMem()->memory_at(alias_idx);
 174     } else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
 175       Node *in = mem->in(0);
 176       // we can safely skip over safepoints, calls, locks and membars because we
 177       // already know that the object is safe to eliminate.
 178       if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
 179         return in;
 180       } else if (in->is_Call()) {
 181         CallNode *call = in->as_Call();
 182         if (call->may_modify(tinst, phase)) {
 183           assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
 184           if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
 185             return in;
 186           }
 187         }
 188         mem = in->in(TypeFunc::Memory);
 189       } else if (in->is_MemBar()) {
 190         ArrayCopyNode* ac = NULL;
 191         if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
 192           if (ac != NULL) {
 193             assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
 194             return ac;
 195           }
 196         }
 197         mem = in->in(TypeFunc::Memory);
 198       } else {
 199 #ifdef ASSERT
 200         in->dump();
 201         mem->dump();
 202         assert(false, "unexpected projection");
 203 #endif
 204       }
 205     } else if (mem->is_Store()) {
 206       const TypePtr* atype = mem->as_Store()->adr_type();
 207       int adr_idx = phase->C->get_alias_index(atype);
 208       if (adr_idx == alias_idx) {
 209         assert(atype->isa_oopptr(), "address type must be oopptr");
 210         int adr_offset = atype->offset();
 211         uint adr_iid = atype->is_oopptr()->instance_id();
 212         // Array elements references have the same alias_idx
 213         // but different offset and different instance_id.
 214         if (adr_offset == offset && adr_iid == alloc->_idx) {
 215           return mem;
 216         }
 217       } else {
 218         assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
 219       }
 220       mem = mem->in(MemNode::Memory);
 221     } else if (mem->is_ClearArray()) {
 222       if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
 223         // Can not bypass initialization of the instance
 224         // we are looking.
 225         debug_only(intptr_t offset;)
 226         assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
 227         InitializeNode* init = alloc->as_Allocate()->initialization();
 228         // We are looking for stored value, return Initialize node
 229         // or memory edge from Allocate node.
 230         if (init != NULL) {
 231           return init;
 232         } else {
 233           return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
 234         }
 235       }
 236       // Otherwise skip it (the call updated 'mem' value).
 237     } else if (mem->Opcode() == Op_SCMemProj) {
 238       mem = mem->in(0);
 239       Node* adr = NULL;
 240       if (mem->is_LoadStore()) {
 241         adr = mem->in(MemNode::Address);
 242       } else {
 243         assert(mem->Opcode() == Op_EncodeISOArray ||
 244                mem->Opcode() == Op_StrCompressedCopy, "sanity");
 245         adr = mem->in(3); // Destination array
 246       }
 247       const TypePtr* atype = adr->bottom_type()->is_ptr();
 248       int adr_idx = phase->C->get_alias_index(atype);
 249       if (adr_idx == alias_idx) {
 250         DEBUG_ONLY(mem->dump();)
 251         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 252         return NULL;
 253       }
 254       mem = mem->in(MemNode::Memory);
 255    } else if (mem->Opcode() == Op_StrInflatedCopy) {
 256       Node* adr = mem->in(3); // Destination array
 257       const TypePtr* atype = adr->bottom_type()->is_ptr();
 258       int adr_idx = phase->C->get_alias_index(atype);
 259       if (adr_idx == alias_idx) {
 260         DEBUG_ONLY(mem->dump();)
 261         assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
 262         return NULL;
 263       }
 264       mem = mem->in(MemNode::Memory);
 265     } else {
 266       return mem;
 267     }
 268     assert(mem != orig_mem, "dead memory loop");
 269   }
 270 }
 271 
 272 // Generate loads from source of the arraycopy for fields of
 273 // destination needed at a deoptimization point
 274 Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type *ftype, AllocateNode *alloc) {
 275   BasicType bt = ft;
 276   const Type *type = ftype;
 277   if (ft == T_NARROWOOP) {
 278     bt = T_OBJECT;
 279     type = ftype->make_oopptr();
 280   }
 281   Node* res = NULL;
 282   if (ac->is_clonebasic()) {
 283     assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
 284     Node* base = ac->in(ArrayCopyNode::Src);
 285     Node* adr = _igvn.transform(new AddPNode(base, base, MakeConX(offset)));
 286     const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
 287     MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 288     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 289     res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 290   } else {
 291     if (ac->modifies(offset, offset, &_igvn, true)) {
 292       assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
 293       uint shift = exact_log2(type2aelembytes(bt));
 294       Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
 295       Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
 296       const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
 297       const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
 298 
 299       Node* adr = NULL;
 300       const TypePtr* adr_type = NULL;
 301       if (src_pos_t->is_con() && dest_pos_t->is_con()) {
 302         intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
 303         Node* base = ac->in(ArrayCopyNode::Src);
 304         adr = _igvn.transform(new AddPNode(base, base, MakeConX(off)));
 305         adr_type = _igvn.type(base)->is_ptr()->add_offset(off);
 306         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 307           // Don't emit a new load from src if src == dst but try to get the value from memory instead
 308           return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
 309         }
 310       } else {
 311         Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
 312 #ifdef _LP64
 313         diff = _igvn.transform(new ConvI2LNode(diff));
 314 #endif
 315         diff = _igvn.transform(new LShiftXNode(diff, intcon(shift)));
 316 
 317         Node* off = _igvn.transform(new AddXNode(MakeConX(offset), diff));
 318         Node* base = ac->in(ArrayCopyNode::Src);
 319         adr = _igvn.transform(new AddPNode(base, base, off));
 320         adr_type = _igvn.type(base)->is_ptr()->add_offset(Type::OffsetBot);
 321         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 322           // Non constant offset in the array: we can't statically
 323           // determine the value
 324           return NULL;
 325         }
 326       }
 327       MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 328       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 329       res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 330     }
 331   }
 332   if (res != NULL) {
 333     if (ftype->isa_narrowoop()) {
 334       // PhaseMacroExpand::scalar_replacement adds DecodeN nodes
 335       res = _igvn.transform(new EncodePNode(res, ftype));
 336     }
 337     return res;
 338   }
 339   return NULL;
 340 }
 341 
 342 //
 343 // Given a Memory Phi, compute a value Phi containing the values from stores
 344 // on the input paths.
 345 // Note: this function is recursive, its depth is limited by the "level" argument
 346 // Returns the computed Phi, or NULL if it cannot compute it.
 347 Node *PhaseMacroExpand::value_from_mem_phi(Node *mem, BasicType ft, const Type *phi_type, const TypeOopPtr *adr_t, AllocateNode *alloc, Node_Stack *value_phis, int level) {
 348   assert(mem->is_Phi(), "sanity");
 349   int alias_idx = C->get_alias_index(adr_t);
 350   int offset = adr_t->offset();
 351   int instance_id = adr_t->instance_id();
 352 
 353   // Check if an appropriate value phi already exists.
 354   Node* region = mem->in(0);
 355   for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
 356     Node* phi = region->fast_out(k);
 357     if (phi->is_Phi() && phi != mem &&
 358         phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
 359       return phi;
 360     }
 361   }
 362   // Check if an appropriate new value phi already exists.
 363   Node* new_phi = value_phis->find(mem->_idx);
 364   if (new_phi != NULL)
 365     return new_phi;
 366 
 367   if (level <= 0) {
 368     return NULL; // Give up: phi tree too deep
 369   }
 370   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 371   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 372 
 373   uint length = mem->req();
 374   GrowableArray <Node *> values(length, length, NULL);
 375 
 376   // create a new Phi for the value
 377   PhiNode *phi = new PhiNode(mem->in(0), phi_type, NULL, mem->_idx, instance_id, alias_idx, offset);
 378   transform_later(phi);
 379   value_phis->push(phi, mem->_idx);
 380 
 381   for (uint j = 1; j < length; j++) {
 382     Node *in = mem->in(j);
 383     if (in == NULL || in->is_top()) {
 384       values.at_put(j, in);
 385     } else  {
 386       Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
 387       if (val == start_mem || val == alloc_mem) {
 388         // hit a sentinel, return appropriate 0 value
 389         values.at_put(j, _igvn.zerocon(ft));
 390         continue;
 391       }
 392       if (val->is_Initialize()) {
 393         val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 394       }
 395       if (val == NULL) {
 396         return NULL;  // can't find a value on this path
 397       }
 398       if (val == mem) {
 399         values.at_put(j, mem);
 400       } else if (val->is_Store()) {
 401         Node* n = val->in(MemNode::ValueIn);
 402         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 403         n = bs->step_over_gc_barrier(n);
 404         if (is_subword_type(ft)) {
 405           n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
 406         }
 407         values.at_put(j, n);
 408       } else if(val->is_Proj() && val->in(0) == alloc) {
 409         values.at_put(j, _igvn.zerocon(ft));
 410       } else if (val->is_Phi()) {
 411         val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
 412         if (val == NULL) {
 413           return NULL;
 414         }
 415         values.at_put(j, val);
 416       } else if (val->Opcode() == Op_SCMemProj) {
 417         assert(val->in(0)->is_LoadStore() ||
 418                val->in(0)->Opcode() == Op_EncodeISOArray ||
 419                val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
 420         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 421         return NULL;
 422       } else if (val->is_ArrayCopy()) {
 423         Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
 424         if (res == NULL) {
 425           return NULL;
 426         }
 427         values.at_put(j, res);
 428       } else {
 429         DEBUG_ONLY( val->dump(); )
 430         assert(false, "unknown node on this path");
 431         return NULL;  // unknown node on this path
 432       }
 433     }
 434   }
 435   // Set Phi's inputs
 436   for (uint j = 1; j < length; j++) {
 437     if (values.at(j) == mem) {
 438       phi->init_req(j, phi);
 439     } else {
 440       phi->init_req(j, values.at(j));
 441     }
 442   }
 443   return phi;
 444 }
 445 
 446 // Search the last value stored into the object's field.
 447 Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType ft, const Type *ftype, const TypeOopPtr *adr_t, AllocateNode *alloc) {
 448   assert(adr_t->is_known_instance_field(), "instance required");
 449   int instance_id = adr_t->instance_id();
 450   assert((uint)instance_id == alloc->_idx, "wrong allocation");
 451 
 452   int alias_idx = C->get_alias_index(adr_t);
 453   int offset = adr_t->offset();
 454   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 455   Node *alloc_ctrl = alloc->in(TypeFunc::Control);
 456   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 457   VectorSet visited;
 458 
 459   bool done = sfpt_mem == alloc_mem;
 460   Node *mem = sfpt_mem;
 461   while (!done) {
 462     if (visited.test_set(mem->_idx)) {
 463       return NULL;  // found a loop, give up
 464     }
 465     mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
 466     if (mem == start_mem || mem == alloc_mem) {
 467       done = true;  // hit a sentinel, return appropriate 0 value
 468     } else if (mem->is_Initialize()) {
 469       mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 470       if (mem == NULL) {
 471         done = true; // Something go wrong.
 472       } else if (mem->is_Store()) {
 473         const TypePtr* atype = mem->as_Store()->adr_type();
 474         assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
 475         done = true;
 476       }
 477     } else if (mem->is_Store()) {
 478       const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
 479       assert(atype != NULL, "address type must be oopptr");
 480       assert(C->get_alias_index(atype) == alias_idx &&
 481              atype->is_known_instance_field() && atype->offset() == offset &&
 482              atype->instance_id() == instance_id, "store is correct memory slice");
 483       done = true;
 484     } else if (mem->is_Phi()) {
 485       // try to find a phi's unique input
 486       Node *unique_input = NULL;
 487       Node *top = C->top();
 488       for (uint i = 1; i < mem->req(); i++) {
 489         Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
 490         if (n == NULL || n == top || n == mem) {
 491           continue;
 492         } else if (unique_input == NULL) {
 493           unique_input = n;
 494         } else if (unique_input != n) {
 495           unique_input = top;
 496           break;
 497         }
 498       }
 499       if (unique_input != NULL && unique_input != top) {
 500         mem = unique_input;
 501       } else {
 502         done = true;
 503       }
 504     } else if (mem->is_ArrayCopy()) {
 505       done = true;
 506     } else {
 507       DEBUG_ONLY( mem->dump(); )
 508       assert(false, "unexpected node");
 509     }
 510   }
 511   if (mem != NULL) {
 512     if (mem == start_mem || mem == alloc_mem) {
 513       // hit a sentinel, return appropriate 0 value
 514       return _igvn.zerocon(ft);
 515     } else if (mem->is_Store()) {
 516       Node* n = mem->in(MemNode::ValueIn);
 517       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 518       n = bs->step_over_gc_barrier(n);
 519       return n;
 520     } else if (mem->is_Phi()) {
 521       // attempt to produce a Phi reflecting the values on the input paths of the Phi
 522       Node_Stack value_phis(8);
 523       Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
 524       if (phi != NULL) {
 525         return phi;
 526       } else {
 527         // Kill all new Phis
 528         while(value_phis.is_nonempty()) {
 529           Node* n = value_phis.node();
 530           _igvn.replace_node(n, C->top());
 531           value_phis.pop();
 532         }
 533       }
 534     } else if (mem->is_ArrayCopy()) {
 535       Node* ctl = mem->in(0);
 536       Node* m = mem->in(TypeFunc::Memory);
 537       if (sfpt_ctl->is_Proj() && sfpt_ctl->as_Proj()->is_uncommon_trap_proj(Deoptimization::Reason_none)) {
 538         // pin the loads in the uncommon trap path
 539         ctl = sfpt_ctl;
 540         m = sfpt_mem;
 541       }
 542       return make_arraycopy_load(mem->as_ArrayCopy(), offset, ctl, m, ft, ftype, alloc);
 543     }
 544   }
 545   // Something go wrong.
 546   return NULL;
 547 }
 548 
 549 // Check the possibility of scalar replacement.
 550 bool PhaseMacroExpand::can_eliminate_allocation(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
 551   //  Scan the uses of the allocation to check for anything that would
 552   //  prevent us from eliminating it.
 553   NOT_PRODUCT( const char* fail_eliminate = NULL; )
 554   DEBUG_ONLY( Node* disq_node = NULL; )
 555   bool  can_eliminate = true;
 556 
 557   Node* res = alloc->result_cast();
 558   const TypeOopPtr* res_type = NULL;
 559   if (res == NULL) {
 560     // All users were eliminated.
 561   } else if (!res->is_CheckCastPP()) {
 562     NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
 563     can_eliminate = false;
 564   } else {
 565     res_type = _igvn.type(res)->isa_oopptr();
 566     if (res_type == NULL) {
 567       NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
 568       can_eliminate = false;
 569     } else if (res_type->isa_aryptr()) {
 570       int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 571       if (length < 0) {
 572         NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
 573         can_eliminate = false;
 574       }
 575     }
 576   }
 577 
 578   if (can_eliminate && res != NULL) {
 579     for (DUIterator_Fast jmax, j = res->fast_outs(jmax);
 580                                j < jmax && can_eliminate; j++) {
 581       Node* use = res->fast_out(j);
 582 
 583       if (use->is_AddP()) {
 584         const TypePtr* addp_type = _igvn.type(use)->is_ptr();
 585         int offset = addp_type->offset();
 586 
 587         if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
 588           NOT_PRODUCT(fail_eliminate = "Undefined field referrence";)
 589           can_eliminate = false;
 590           break;
 591         }
 592         for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
 593                                    k < kmax && can_eliminate; k++) {
 594           Node* n = use->fast_out(k);
 595           if (!n->is_Store() && n->Opcode() != Op_CastP2X
 596               SHENANDOAHGC_ONLY(&& (!UseShenandoahGC || !ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(n))) ) {
 597             DEBUG_ONLY(disq_node = n;)
 598             if (n->is_Load() || n->is_LoadStore()) {
 599               NOT_PRODUCT(fail_eliminate = "Field load";)
 600             } else {
 601               NOT_PRODUCT(fail_eliminate = "Not store field referrence";)
 602             }
 603             can_eliminate = false;
 604           }
 605         }
 606       } else if (use->is_ArrayCopy() &&
 607                  (use->as_ArrayCopy()->is_clonebasic() ||
 608                   use->as_ArrayCopy()->is_arraycopy_validated() ||
 609                   use->as_ArrayCopy()->is_copyof_validated() ||
 610                   use->as_ArrayCopy()->is_copyofrange_validated()) &&
 611                  use->in(ArrayCopyNode::Dest) == res) {
 612         // ok to eliminate
 613       } else if (use->is_SafePoint()) {
 614         SafePointNode* sfpt = use->as_SafePoint();
 615         if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
 616           // Object is passed as argument.
 617           DEBUG_ONLY(disq_node = use;)
 618           NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
 619           can_eliminate = false;
 620         }
 621         Node* sfptMem = sfpt->memory();
 622         if (sfptMem == NULL || sfptMem->is_top()) {
 623           DEBUG_ONLY(disq_node = use;)
 624           NOT_PRODUCT(fail_eliminate = "NULL or TOP memory";)
 625           can_eliminate = false;
 626         } else {
 627           safepoints.append_if_missing(sfpt);
 628         }
 629       } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
 630         if (use->is_Phi()) {
 631           if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
 632             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 633           } else {
 634             NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
 635           }
 636           DEBUG_ONLY(disq_node = use;)
 637         } else {
 638           if (use->Opcode() == Op_Return) {
 639             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 640           }else {
 641             NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
 642           }
 643           DEBUG_ONLY(disq_node = use;)
 644         }
 645         can_eliminate = false;
 646       }
 647     }
 648   }
 649 
 650 #ifndef PRODUCT
 651   if (PrintEliminateAllocations) {
 652     if (can_eliminate) {
 653       tty->print("Scalar ");
 654       if (res == NULL)
 655         alloc->dump();
 656       else
 657         res->dump();
 658     } else if (alloc->_is_scalar_replaceable) {
 659       tty->print("NotScalar (%s)", fail_eliminate);
 660       if (res == NULL)
 661         alloc->dump();
 662       else
 663         res->dump();
 664 #ifdef ASSERT
 665       if (disq_node != NULL) {
 666           tty->print("  >>>> ");
 667           disq_node->dump();
 668       }
 669 #endif /*ASSERT*/
 670     }
 671   }
 672 #endif
 673   return can_eliminate;
 674 }
 675 
 676 // Do scalar replacement.
 677 bool PhaseMacroExpand::scalar_replacement(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
 678   GrowableArray <SafePointNode *> safepoints_done;
 679 
 680   ciKlass* klass = NULL;
 681   ciInstanceKlass* iklass = NULL;
 682   int nfields = 0;
 683   int array_base = 0;
 684   int element_size = 0;
 685   BasicType basic_elem_type = T_ILLEGAL;
 686   ciType* elem_type = NULL;
 687 
 688   Node* res = alloc->result_cast();
 689   assert(res == NULL || res->is_CheckCastPP(), "unexpected AllocateNode result");
 690   const TypeOopPtr* res_type = NULL;
 691   if (res != NULL) { // Could be NULL when there are no users
 692     res_type = _igvn.type(res)->isa_oopptr();
 693   }
 694 
 695   if (res != NULL) {
 696     klass = res_type->klass();
 697     if (res_type->isa_instptr()) {
 698       // find the fields of the class which will be needed for safepoint debug information
 699       assert(klass->is_instance_klass(), "must be an instance klass.");
 700       iklass = klass->as_instance_klass();
 701       nfields = iklass->nof_nonstatic_fields();
 702     } else {
 703       // find the array's elements which will be needed for safepoint debug information
 704       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 705       assert(klass->is_array_klass() && nfields >= 0, "must be an array klass.");
 706       elem_type = klass->as_array_klass()->element_type();
 707       basic_elem_type = elem_type->basic_type();
 708       array_base = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
 709       element_size = type2aelembytes(basic_elem_type);
 710     }
 711   }
 712   //
 713   // Process the safepoint uses
 714   //
 715   while (safepoints.length() > 0) {
 716     SafePointNode* sfpt = safepoints.pop();
 717     Node* mem = sfpt->memory();
 718     Node* ctl = sfpt->control();
 719     assert(sfpt->jvms() != NULL, "missed JVMS");
 720     // Fields of scalar objs are referenced only at the end
 721     // of regular debuginfo at the last (youngest) JVMS.
 722     // Record relative start index.
 723     uint first_ind = (sfpt->req() - sfpt->jvms()->scloff());
 724     SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type,
 725 #ifdef ASSERT
 726                                                  alloc,
 727 #endif
 728                                                  first_ind, nfields);
 729     sobj->init_req(0, C->root());
 730     transform_later(sobj);
 731 
 732     // Scan object's fields adding an input to the safepoint for each field.
 733     for (int j = 0; j < nfields; j++) {
 734       intptr_t offset;
 735       ciField* field = NULL;
 736       if (iklass != NULL) {
 737         field = iklass->nonstatic_field_at(j);
 738         offset = field->offset();
 739         elem_type = field->type();
 740         basic_elem_type = field->layout_type();
 741       } else {
 742         offset = array_base + j * (intptr_t)element_size;
 743       }
 744 
 745       const Type *field_type;
 746       // The next code is taken from Parse::do_get_xxx().
 747       if (is_reference_type(basic_elem_type)) {
 748         if (!elem_type->is_loaded()) {
 749           field_type = TypeInstPtr::BOTTOM;
 750         } else if (field != NULL && field->is_static_constant()) {
 751           // This can happen if the constant oop is non-perm.
 752           ciObject* con = field->constant_value().as_object();
 753           // Do not "join" in the previous type; it doesn't add value,
 754           // and may yield a vacuous result if the field is of interface type.
 755           field_type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
 756           assert(field_type != NULL, "field singleton type must be consistent");
 757         } else {
 758           field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
 759         }
 760         if (UseCompressedOops) {
 761           field_type = field_type->make_narrowoop();
 762           basic_elem_type = T_NARROWOOP;
 763         }
 764       } else {
 765         field_type = Type::get_const_basic_type(basic_elem_type);
 766       }
 767 
 768       const TypeOopPtr *field_addr_type = res_type->add_offset(offset)->isa_oopptr();
 769 
 770       Node *field_val = value_from_mem(mem, ctl, basic_elem_type, field_type, field_addr_type, alloc);
 771       if (field_val == NULL) {
 772         // We weren't able to find a value for this field,
 773         // give up on eliminating this allocation.
 774 
 775         // Remove any extra entries we added to the safepoint.
 776         uint last = sfpt->req() - 1;
 777         for (int k = 0;  k < j; k++) {
 778           sfpt->del_req(last--);
 779         }
 780         _igvn._worklist.push(sfpt);
 781         // rollback processed safepoints
 782         while (safepoints_done.length() > 0) {
 783           SafePointNode* sfpt_done = safepoints_done.pop();
 784           // remove any extra entries we added to the safepoint
 785           last = sfpt_done->req() - 1;
 786           for (int k = 0;  k < nfields; k++) {
 787             sfpt_done->del_req(last--);
 788           }
 789           JVMState *jvms = sfpt_done->jvms();
 790           jvms->set_endoff(sfpt_done->req());
 791           // Now make a pass over the debug information replacing any references
 792           // to SafePointScalarObjectNode with the allocated object.
 793           int start = jvms->debug_start();
 794           int end   = jvms->debug_end();
 795           for (int i = start; i < end; i++) {
 796             if (sfpt_done->in(i)->is_SafePointScalarObject()) {
 797               SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
 798               if (scobj->first_index(jvms) == sfpt_done->req() &&
 799                   scobj->n_fields() == (uint)nfields) {
 800                 assert(scobj->alloc() == alloc, "sanity");
 801                 sfpt_done->set_req(i, res);
 802               }
 803             }
 804           }
 805           _igvn._worklist.push(sfpt_done);
 806         }
 807 #ifndef PRODUCT
 808         if (PrintEliminateAllocations) {
 809           if (field != NULL) {
 810             tty->print("=== At SafePoint node %d can't find value of Field: ",
 811                        sfpt->_idx);
 812             field->print();
 813             int field_idx = C->get_alias_index(field_addr_type);
 814             tty->print(" (alias_idx=%d)", field_idx);
 815           } else { // Array's element
 816             tty->print("=== At SafePoint node %d can't find value of array element [%d]",
 817                        sfpt->_idx, j);
 818           }
 819           tty->print(", which prevents elimination of: ");
 820           if (res == NULL)
 821             alloc->dump();
 822           else
 823             res->dump();
 824         }
 825 #endif
 826         return false;
 827       }
 828       if (UseCompressedOops && field_type->isa_narrowoop()) {
 829         // Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
 830         // to be able scalar replace the allocation.
 831         if (field_val->is_EncodeP()) {
 832           field_val = field_val->in(1);
 833         } else {
 834           field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
 835         }
 836       }
 837       sfpt->add_req(field_val);
 838     }
 839     JVMState *jvms = sfpt->jvms();
 840     jvms->set_endoff(sfpt->req());
 841     // Now make a pass over the debug information replacing any references
 842     // to the allocated object with "sobj"
 843     int start = jvms->debug_start();
 844     int end   = jvms->debug_end();
 845     sfpt->replace_edges_in_range(res, sobj, start, end, &_igvn);
 846     _igvn._worklist.push(sfpt);
 847     safepoints_done.append_if_missing(sfpt); // keep it for rollback
 848   }
 849   return true;
 850 }
 851 
 852 static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
 853   Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
 854   Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
 855   if (ctl_proj != NULL) {
 856     igvn.replace_node(ctl_proj, n->in(0));
 857   }
 858   if (mem_proj != NULL) {
 859     igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
 860   }
 861 }
 862 
 863 // Process users of eliminated allocation.
 864 void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc) {
 865   Node* res = alloc->result_cast();
 866   if (res != NULL) {
 867     for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
 868       Node *use = res->last_out(j);
 869       uint oc1 = res->outcnt();
 870 
 871       if (use->is_AddP()) {
 872         for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
 873           Node *n = use->last_out(k);
 874           uint oc2 = use->outcnt();
 875           if (n->is_Store()) {
 876 #ifdef ASSERT
 877             // Verify that there is no dependent MemBarVolatile nodes,
 878             // they should be removed during IGVN, see MemBarNode::Ideal().
 879             for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
 880                                        p < pmax; p++) {
 881               Node* mb = n->fast_out(p);
 882               assert(mb->is_Initialize() || !mb->is_MemBar() ||
 883                      mb->req() <= MemBarNode::Precedent ||
 884                      mb->in(MemBarNode::Precedent) != n,
 885                      "MemBarVolatile should be eliminated for non-escaping object");
 886             }
 887 #endif
 888             _igvn.replace_node(n, n->in(MemNode::Memory));
 889           } else {
 890             eliminate_gc_barrier(n);
 891           }
 892           k -= (oc2 - use->outcnt());
 893         }
 894         _igvn.remove_dead_node(use);
 895       } else if (use->is_ArrayCopy()) {
 896         // Disconnect ArrayCopy node
 897         ArrayCopyNode* ac = use->as_ArrayCopy();
 898         if (ac->is_clonebasic()) {
 899           Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
 900           disconnect_projections(ac, _igvn);
 901           assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
 902           Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
 903           disconnect_projections(membar_before->as_MemBar(), _igvn);
 904           if (membar_after->is_MemBar()) {
 905             disconnect_projections(membar_after->as_MemBar(), _igvn);
 906           }
 907         } else {
 908           assert(ac->is_arraycopy_validated() ||
 909                  ac->is_copyof_validated() ||
 910                  ac->is_copyofrange_validated(), "unsupported");
 911           CallProjections callprojs;
 912           ac->extract_projections(&callprojs, true);
 913 
 914           _igvn.replace_node(callprojs.fallthrough_ioproj, ac->in(TypeFunc::I_O));
 915           _igvn.replace_node(callprojs.fallthrough_memproj, ac->in(TypeFunc::Memory));
 916           _igvn.replace_node(callprojs.fallthrough_catchproj, ac->in(TypeFunc::Control));
 917 
 918           // Set control to top. IGVN will remove the remaining projections
 919           ac->set_req(0, top());
 920           ac->replace_edge(res, top(), &_igvn);
 921 
 922           // Disconnect src right away: it can help find new
 923           // opportunities for allocation elimination
 924           Node* src = ac->in(ArrayCopyNode::Src);
 925           ac->replace_edge(src, top(), &_igvn);
 926           // src can be top at this point if src and dest of the
 927           // arraycopy were the same
 928           if (src->outcnt() == 0 && !src->is_top()) {
 929             _igvn.remove_dead_node(src);
 930           }
 931         }
 932         _igvn._worklist.push(ac);
 933       } else {
 934         eliminate_gc_barrier(use);
 935       }
 936       j -= (oc1 - res->outcnt());
 937     }
 938     assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
 939     _igvn.remove_dead_node(res);
 940   }
 941 
 942   //
 943   // Process other users of allocation's projections
 944   //
 945   if (_callprojs.resproj != NULL && _callprojs.resproj->outcnt() != 0) {
 946     // First disconnect stores captured by Initialize node.
 947     // If Initialize node is eliminated first in the following code,
 948     // it will kill such stores and DUIterator_Last will assert.
 949     for (DUIterator_Fast jmax, j = _callprojs.resproj->fast_outs(jmax);  j < jmax; j++) {
 950       Node* use = _callprojs.resproj->fast_out(j);
 951       if (use->is_AddP()) {
 952         // raw memory addresses used only by the initialization
 953         _igvn.replace_node(use, C->top());
 954         --j; --jmax;
 955       }
 956     }
 957     for (DUIterator_Last jmin, j = _callprojs.resproj->last_outs(jmin); j >= jmin; ) {
 958       Node* use = _callprojs.resproj->last_out(j);
 959       uint oc1 = _callprojs.resproj->outcnt();
 960       if (use->is_Initialize()) {
 961         // Eliminate Initialize node.
 962         InitializeNode *init = use->as_Initialize();
 963         assert(init->outcnt() <= 2, "only a control and memory projection expected");
 964         Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
 965         if (ctrl_proj != NULL) {
 966           _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
 967 #ifdef ASSERT
 968           // If the InitializeNode has no memory out, it will die, and tmp will become NULL
 969           Node* tmp = init->in(TypeFunc::Control);
 970           assert(tmp == NULL || tmp == _callprojs.fallthrough_catchproj, "allocation control projection");
 971 #endif
 972         }
 973         Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
 974         if (mem_proj != NULL) {
 975           Node *mem = init->in(TypeFunc::Memory);
 976 #ifdef ASSERT
 977           if (mem->is_MergeMem()) {
 978             assert(mem->in(TypeFunc::Memory) == _callprojs.fallthrough_memproj, "allocation memory projection");
 979           } else {
 980             assert(mem == _callprojs.fallthrough_memproj, "allocation memory projection");
 981           }
 982 #endif
 983           _igvn.replace_node(mem_proj, mem);
 984         }
 985       } else  {
 986         assert(false, "only Initialize or AddP expected");
 987       }
 988       j -= (oc1 - _callprojs.resproj->outcnt());
 989     }
 990   }
 991   if (_callprojs.fallthrough_catchproj != NULL) {
 992     _igvn.replace_node(_callprojs.fallthrough_catchproj, alloc->in(TypeFunc::Control));
 993   }
 994   if (_callprojs.fallthrough_memproj != NULL) {
 995     _igvn.replace_node(_callprojs.fallthrough_memproj, alloc->in(TypeFunc::Memory));
 996   }
 997   if (_callprojs.catchall_memproj != NULL) {
 998     _igvn.replace_node(_callprojs.catchall_memproj, C->top());
 999   }
1000   if (_callprojs.fallthrough_ioproj != NULL) {
1001     _igvn.replace_node(_callprojs.fallthrough_ioproj, alloc->in(TypeFunc::I_O));
1002   }
1003   if (_callprojs.catchall_ioproj != NULL) {
1004     _igvn.replace_node(_callprojs.catchall_ioproj, C->top());
1005   }
1006   if (_callprojs.catchall_catchproj != NULL) {
1007     _igvn.replace_node(_callprojs.catchall_catchproj, C->top());
1008   }
1009 }
1010 
1011 bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
1012   // If reallocation fails during deoptimization we'll pop all
1013   // interpreter frames for this compiled frame and that won't play
1014   // nice with JVMTI popframe.
1015   // We avoid this issue by eager reallocation when the popframe request
1016   // is received.
1017   if (!EliminateAllocations || !alloc->_is_non_escaping) {
1018     return false;
1019   }
1020   Node* klass = alloc->in(AllocateNode::KlassNode);
1021   const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
1022   Node* res = alloc->result_cast();
1023   // Eliminate boxing allocations which are not used
1024   // regardless scalar replacable status.
1025   bool boxing_alloc = C->eliminate_boxing() &&
1026                       tklass->klass()->is_instance_klass()  &&
1027                       tklass->klass()->as_instance_klass()->is_box_klass();
1028   if (!alloc->_is_scalar_replaceable && (!boxing_alloc || (res != NULL))) {
1029     return false;
1030   }
1031 
1032   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1033 
1034   GrowableArray <SafePointNode *> safepoints;
1035   if (!can_eliminate_allocation(alloc, safepoints)) {
1036     return false;
1037   }
1038 
1039   if (!alloc->_is_scalar_replaceable) {
1040     assert(res == NULL, "sanity");
1041     // We can only eliminate allocation if all debug info references
1042     // are already replaced with SafePointScalarObject because
1043     // we can't search for a fields value without instance_id.
1044     if (safepoints.length() > 0) {
1045       return false;
1046     }
1047   }
1048 
1049   if (!scalar_replacement(alloc, safepoints)) {
1050     return false;
1051   }
1052 
1053   CompileLog* log = C->log();
1054   if (log != NULL) {
1055     log->head("eliminate_allocation type='%d'",
1056               log->identify(tklass->klass()));
1057     JVMState* p = alloc->jvms();
1058     while (p != NULL) {
1059       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1060       p = p->caller();
1061     }
1062     log->tail("eliminate_allocation");
1063   }
1064 
1065   process_users_of_allocation(alloc);
1066 
1067 #ifndef PRODUCT
1068   if (PrintEliminateAllocations) {
1069     if (alloc->is_AllocateArray())
1070       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1071     else
1072       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1073   }
1074 #endif
1075 
1076   return true;
1077 }
1078 
1079 bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
1080   // EA should remove all uses of non-escaping boxing node.
1081   if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != NULL) {
1082     return false;
1083   }
1084 
1085   assert(boxing->result_cast() == NULL, "unexpected boxing node result");
1086 
1087   boxing->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1088 
1089   const TypeTuple* r = boxing->tf()->range();
1090   assert(r->cnt() > TypeFunc::Parms, "sanity");
1091   const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
1092   assert(t != NULL, "sanity");
1093 
1094   CompileLog* log = C->log();
1095   if (log != NULL) {
1096     log->head("eliminate_boxing type='%d'",
1097               log->identify(t->klass()));
1098     JVMState* p = boxing->jvms();
1099     while (p != NULL) {
1100       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1101       p = p->caller();
1102     }
1103     log->tail("eliminate_boxing");
1104   }
1105 
1106   process_users_of_allocation(boxing);
1107 
1108 #ifndef PRODUCT
1109   if (PrintEliminateAllocations) {
1110     tty->print("++++ Eliminated: %d ", boxing->_idx);
1111     boxing->method()->print_short_name(tty);
1112     tty->cr();
1113   }
1114 #endif
1115 
1116   return true;
1117 }
1118 
1119 //---------------------------set_eden_pointers-------------------------
1120 void PhaseMacroExpand::set_eden_pointers(Node* &eden_top_adr, Node* &eden_end_adr) {
1121   if (UseTLAB) {                // Private allocation: load from TLS
1122     Node* thread = transform_later(new ThreadLocalNode());
1123     int tlab_top_offset = in_bytes(JavaThread::tlab_top_offset());
1124     int tlab_end_offset = in_bytes(JavaThread::tlab_end_offset());
1125     eden_top_adr = basic_plus_adr(top()/*not oop*/, thread, tlab_top_offset);
1126     eden_end_adr = basic_plus_adr(top()/*not oop*/, thread, tlab_end_offset);
1127   } else {                      // Shared allocation: load from globals
1128     CollectedHeap* ch = Universe::heap();
1129     address top_adr = (address)ch->top_addr();
1130     address end_adr = (address)ch->end_addr();
1131     eden_top_adr = makecon(TypeRawPtr::make(top_adr));
1132     eden_end_adr = basic_plus_adr(eden_top_adr, end_adr - top_adr);
1133   }
1134 }
1135 
1136 
1137 Node* PhaseMacroExpand::make_load(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
1138   Node* adr = basic_plus_adr(base, offset);
1139   const TypePtr* adr_type = adr->bottom_type()->is_ptr();
1140   Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
1141   transform_later(value);
1142   return value;
1143 }
1144 
1145 
1146 Node* PhaseMacroExpand::make_store(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
1147   Node* adr = basic_plus_adr(base, offset);
1148   mem = StoreNode::make(_igvn, ctl, mem, adr, NULL, value, bt, MemNode::unordered);
1149   transform_later(mem);
1150   return mem;
1151 }
1152 
1153 //=============================================================================
1154 //
1155 //                              A L L O C A T I O N
1156 //
1157 // Allocation attempts to be fast in the case of frequent small objects.
1158 // It breaks down like this:
1159 //
1160 // 1) Size in doublewords is computed.  This is a constant for objects and
1161 // variable for most arrays.  Doubleword units are used to avoid size
1162 // overflow of huge doubleword arrays.  We need doublewords in the end for
1163 // rounding.
1164 //
1165 // 2) Size is checked for being 'too large'.  Too-large allocations will go
1166 // the slow path into the VM.  The slow path can throw any required
1167 // exceptions, and does all the special checks for very large arrays.  The
1168 // size test can constant-fold away for objects.  For objects with
1169 // finalizers it constant-folds the otherway: you always go slow with
1170 // finalizers.
1171 //
1172 // 3) If NOT using TLABs, this is the contended loop-back point.
1173 // Load-Locked the heap top.  If using TLABs normal-load the heap top.
1174 //
1175 // 4) Check that heap top + size*8 < max.  If we fail go the slow ` route.
1176 // NOTE: "top+size*8" cannot wrap the 4Gig line!  Here's why: for largish
1177 // "size*8" we always enter the VM, where "largish" is a constant picked small
1178 // enough that there's always space between the eden max and 4Gig (old space is
1179 // there so it's quite large) and large enough that the cost of entering the VM
1180 // is dwarfed by the cost to initialize the space.
1181 //
1182 // 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
1183 // down.  If contended, repeat at step 3.  If using TLABs normal-store
1184 // adjusted heap top back down; there is no contention.
1185 //
1186 // 6) If !ZeroTLAB then Bulk-clear the object/array.  Fill in klass & mark
1187 // fields.
1188 //
1189 // 7) Merge with the slow-path; cast the raw memory pointer to the correct
1190 // oop flavor.
1191 //
1192 //=============================================================================
1193 // FastAllocateSizeLimit value is in DOUBLEWORDS.
1194 // Allocations bigger than this always go the slow route.
1195 // This value must be small enough that allocation attempts that need to
1196 // trigger exceptions go the slow route.  Also, it must be small enough so
1197 // that heap_top + size_in_bytes does not wrap around the 4Gig limit.
1198 //=============================================================================j//
1199 // %%% Here is an old comment from parseHelper.cpp; is it outdated?
1200 // The allocator will coalesce int->oop copies away.  See comment in
1201 // coalesce.cpp about how this works.  It depends critically on the exact
1202 // code shape produced here, so if you are changing this code shape
1203 // make sure the GC info for the heap-top is correct in and around the
1204 // slow-path call.
1205 //
1206 
1207 void PhaseMacroExpand::expand_allocate_common(
1208             AllocateNode* alloc, // allocation node to be expanded
1209             Node* length,  // array length for an array allocation
1210             const TypeFunc* slow_call_type, // Type of slow call
1211             address slow_call_address  // Address of slow call
1212     )
1213 {
1214   Node* ctrl = alloc->in(TypeFunc::Control);
1215   Node* mem  = alloc->in(TypeFunc::Memory);
1216   Node* i_o  = alloc->in(TypeFunc::I_O);
1217   Node* size_in_bytes     = alloc->in(AllocateNode::AllocSize);
1218   Node* klass_node        = alloc->in(AllocateNode::KlassNode);
1219   Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
1220   assert(ctrl != NULL, "must have control");
1221 
1222   // We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
1223   // they will not be used if "always_slow" is set
1224   enum { slow_result_path = 1, fast_result_path = 2 };
1225   Node *result_region = NULL;
1226   Node *result_phi_rawmem = NULL;
1227   Node *result_phi_rawoop = NULL;
1228   Node *result_phi_i_o = NULL;
1229 
1230   // The initial slow comparison is a size check, the comparison
1231   // we want to do is a BoolTest::gt
1232   bool expand_fast_path = true;
1233   int tv = _igvn.find_int_con(initial_slow_test, -1);
1234   if (tv >= 0) {
1235     // InitialTest has constant result
1236     //   0 - can fit in TLAB
1237     //   1 - always too big or negative
1238     assert(tv <= 1, "0 or 1 if a constant");
1239     expand_fast_path = (tv == 0);
1240     initial_slow_test = NULL;
1241   } else {
1242     initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
1243   }
1244 
1245   if (C->env()->dtrace_alloc_probes() ||
1246       (!UseTLAB && !Universe::heap()->supports_inline_contig_alloc())) {
1247     // Force slow-path allocation
1248     expand_fast_path = false;
1249     initial_slow_test = NULL;
1250   }
1251 
1252   bool allocation_has_use = (alloc->result_cast() != NULL);
1253   if (!allocation_has_use) {
1254     InitializeNode* init = alloc->initialization();
1255     if (init != NULL) {
1256       init->remove(&_igvn);
1257     }
1258     if (expand_fast_path && (initial_slow_test == NULL)) {
1259       // Remove allocation node and return.
1260       // Size is a non-negative constant -> no initial check needed -> directly to fast path.
1261       // Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
1262 #ifndef PRODUCT
1263       if (PrintEliminateAllocations) {
1264         tty->print("NotUsed ");
1265         Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
1266         if (res != NULL) {
1267           res->dump();
1268         } else {
1269           alloc->dump();
1270         }
1271       }
1272 #endif
1273       yank_alloc_node(alloc);
1274       return;
1275     }
1276   }
1277 
1278   enum { too_big_or_final_path = 1, need_gc_path = 2 };
1279   Node *slow_region = NULL;
1280   Node *toobig_false = ctrl;
1281 
1282   // generate the initial test if necessary
1283   if (initial_slow_test != NULL ) {
1284     assert (expand_fast_path, "Only need test if there is a fast path");
1285     slow_region = new RegionNode(3);
1286 
1287     // Now make the initial failure test.  Usually a too-big test but
1288     // might be a TRUE for finalizers or a fancy class check for
1289     // newInstance0.
1290     IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
1291     transform_later(toobig_iff);
1292     // Plug the failing-too-big test into the slow-path region
1293     Node *toobig_true = new IfTrueNode( toobig_iff );
1294     transform_later(toobig_true);
1295     slow_region    ->init_req( too_big_or_final_path, toobig_true );
1296     toobig_false = new IfFalseNode( toobig_iff );
1297     transform_later(toobig_false);
1298   } else {
1299     // No initial test, just fall into next case
1300     assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
1301     toobig_false = ctrl;
1302     debug_only(slow_region = NodeSentinel);
1303   }
1304 
1305   // If we are here there are several possibilities
1306   // - expand_fast_path is false - then only a slow path is expanded. That's it.
1307   // no_initial_check means a constant allocation.
1308   // - If check always evaluates to false -> expand_fast_path is false (see above)
1309   // - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
1310   // if !allocation_has_use the fast path is empty
1311   // if !allocation_has_use && no_initial_check
1312   // - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
1313   //   removed by yank_alloc_node above.
1314 
1315   Node *slow_mem = mem;  // save the current memory state for slow path
1316   // generate the fast allocation code unless we know that the initial test will always go slow
1317   if (expand_fast_path) {
1318     // Fast path modifies only raw memory.
1319     if (mem->is_MergeMem()) {
1320       mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1321     }
1322 
1323     // allocate the Region and Phi nodes for the result
1324     result_region = new RegionNode(3);
1325     result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
1326     result_phi_i_o    = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
1327 
1328     // Grab regular I/O before optional prefetch may change it.
1329     // Slow-path does no I/O so just set it to the original I/O.
1330     result_phi_i_o->init_req(slow_result_path, i_o);
1331 
1332     // Name successful fast-path variables
1333     Node* fast_oop_ctrl;
1334     Node* fast_oop_rawmem;
1335     if (allocation_has_use) {
1336       Node* needgc_ctrl = NULL;
1337       result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
1338 
1339       intx prefetch_lines = length != NULL ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
1340       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1341       Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
1342                                         fast_oop_ctrl, fast_oop_rawmem,
1343                                         prefetch_lines);
1344 
1345       if (initial_slow_test != NULL) {
1346         // This completes all paths into the slow merge point
1347         slow_region->init_req(need_gc_path, needgc_ctrl);
1348         transform_later(slow_region);
1349       } else {
1350         // No initial slow path needed!
1351         // Just fall from the need-GC path straight into the VM call.
1352         slow_region = needgc_ctrl;
1353       }
1354 
1355       InitializeNode* init = alloc->initialization();
1356       fast_oop_rawmem = initialize_object(alloc,
1357                                           fast_oop_ctrl, fast_oop_rawmem, fast_oop,
1358                                           klass_node, length, size_in_bytes);
1359       expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
1360       expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
1361 
1362       result_phi_rawoop->init_req(fast_result_path, fast_oop);
1363     } else {
1364       assert (initial_slow_test != NULL, "sanity");
1365       fast_oop_ctrl   = toobig_false;
1366       fast_oop_rawmem = mem;
1367       transform_later(slow_region);
1368     }
1369 
1370     // Plug in the successful fast-path into the result merge point
1371     result_region    ->init_req(fast_result_path, fast_oop_ctrl);
1372     result_phi_i_o   ->init_req(fast_result_path, i_o);
1373     result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
1374   } else {
1375     slow_region = ctrl;
1376     result_phi_i_o = i_o; // Rename it to use in the following code.
1377   }
1378 
1379   // Generate slow-path call
1380   CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
1381                                OptoRuntime::stub_name(slow_call_address),
1382                                TypePtr::BOTTOM);
1383   call->init_req(TypeFunc::Control,   slow_region);
1384   call->init_req(TypeFunc::I_O,       top());    // does no i/o
1385   call->init_req(TypeFunc::Memory,    slow_mem); // may gc ptrs
1386   call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1387   call->init_req(TypeFunc::FramePtr,  alloc->in(TypeFunc::FramePtr));
1388 
1389   call->init_req(TypeFunc::Parms+0, klass_node);
1390   if (length != NULL) {
1391     call->init_req(TypeFunc::Parms+1, length);
1392   }
1393 
1394   // Copy debug information and adjust JVMState information, then replace
1395   // allocate node with the call
1396   call->copy_call_debug_info(&_igvn, alloc);
1397   if (expand_fast_path) {
1398     call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
1399   } else {
1400     // Hook i_o projection to avoid its elimination during allocation
1401     // replacement (when only a slow call is generated).
1402     call->set_req(TypeFunc::I_O, result_phi_i_o);
1403   }
1404   _igvn.replace_node(alloc, call);
1405   transform_later(call);
1406 
1407   // Identify the output projections from the allocate node and
1408   // adjust any references to them.
1409   // The control and io projections look like:
1410   //
1411   //        v---Proj(ctrl) <-----+   v---CatchProj(ctrl)
1412   //  Allocate                   Catch
1413   //        ^---Proj(io) <-------+   ^---CatchProj(io)
1414   //
1415   //  We are interested in the CatchProj nodes.
1416   //
1417   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1418 
1419   // An allocate node has separate memory projections for the uses on
1420   // the control and i_o paths. Replace the control memory projection with
1421   // result_phi_rawmem (unless we are only generating a slow call when
1422   // both memory projections are combined)
1423   if (expand_fast_path && _callprojs.fallthrough_memproj != NULL) {
1424     migrate_outs(_callprojs.fallthrough_memproj, result_phi_rawmem);
1425   }
1426   // Now change uses of catchall_memproj to use fallthrough_memproj and delete
1427   // catchall_memproj so we end up with a call that has only 1 memory projection.
1428   if (_callprojs.catchall_memproj != NULL ) {
1429     if (_callprojs.fallthrough_memproj == NULL) {
1430       _callprojs.fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
1431       transform_later(_callprojs.fallthrough_memproj);
1432     }
1433     migrate_outs(_callprojs.catchall_memproj, _callprojs.fallthrough_memproj);
1434     _igvn.remove_dead_node(_callprojs.catchall_memproj);
1435   }
1436 
1437   // An allocate node has separate i_o projections for the uses on the control
1438   // and i_o paths. Always replace the control i_o projection with result i_o
1439   // otherwise incoming i_o become dead when only a slow call is generated
1440   // (it is different from memory projections where both projections are
1441   // combined in such case).
1442   if (_callprojs.fallthrough_ioproj != NULL) {
1443     migrate_outs(_callprojs.fallthrough_ioproj, result_phi_i_o);
1444   }
1445   // Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
1446   // catchall_ioproj so we end up with a call that has only 1 i_o projection.
1447   if (_callprojs.catchall_ioproj != NULL ) {
1448     if (_callprojs.fallthrough_ioproj == NULL) {
1449       _callprojs.fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
1450       transform_later(_callprojs.fallthrough_ioproj);
1451     }
1452     migrate_outs(_callprojs.catchall_ioproj, _callprojs.fallthrough_ioproj);
1453     _igvn.remove_dead_node(_callprojs.catchall_ioproj);
1454   }
1455 
1456   // if we generated only a slow call, we are done
1457   if (!expand_fast_path) {
1458     // Now we can unhook i_o.
1459     if (result_phi_i_o->outcnt() > 1) {
1460       call->set_req(TypeFunc::I_O, top());
1461     } else {
1462       assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
1463       // Case of new array with negative size known during compilation.
1464       // AllocateArrayNode::Ideal() optimization disconnect unreachable
1465       // following code since call to runtime will throw exception.
1466       // As result there will be no users of i_o after the call.
1467       // Leave i_o attached to this call to avoid problems in preceding graph.
1468     }
1469     return;
1470   }
1471 
1472   if (_callprojs.fallthrough_catchproj != NULL) {
1473     ctrl = _callprojs.fallthrough_catchproj->clone();
1474     transform_later(ctrl);
1475     _igvn.replace_node(_callprojs.fallthrough_catchproj, result_region);
1476   } else {
1477     ctrl = top();
1478   }
1479   Node *slow_result;
1480   if (_callprojs.resproj == NULL) {
1481     // no uses of the allocation result
1482     slow_result = top();
1483   } else {
1484     slow_result = _callprojs.resproj->clone();
1485     transform_later(slow_result);
1486     _igvn.replace_node(_callprojs.resproj, result_phi_rawoop);
1487   }
1488 
1489   // Plug slow-path into result merge point
1490   result_region->init_req( slow_result_path, ctrl);
1491   transform_later(result_region);
1492   if (allocation_has_use) {
1493     result_phi_rawoop->init_req(slow_result_path, slow_result);
1494     transform_later(result_phi_rawoop);
1495   }
1496   result_phi_rawmem->init_req(slow_result_path, _callprojs.fallthrough_memproj);
1497   transform_later(result_phi_rawmem);
1498   transform_later(result_phi_i_o);
1499   // This completes all paths into the result merge point
1500 }
1501 
1502 // Remove alloc node that has no uses.
1503 void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
1504   Node* ctrl = alloc->in(TypeFunc::Control);
1505   Node* mem  = alloc->in(TypeFunc::Memory);
1506   Node* i_o  = alloc->in(TypeFunc::I_O);
1507 
1508   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1509   if (_callprojs.resproj != NULL) {
1510     for (DUIterator_Fast imax, i = _callprojs.resproj->fast_outs(imax); i < imax; i++) {
1511       Node* use = _callprojs.resproj->fast_out(i);
1512       use->isa_MemBar()->remove(&_igvn);
1513       --imax;
1514       --i; // back up iterator
1515     }
1516     assert(_callprojs.resproj->outcnt() == 0, "all uses must be deleted");
1517     _igvn.remove_dead_node(_callprojs.resproj);
1518   }
1519   if (_callprojs.fallthrough_catchproj != NULL) {
1520     migrate_outs(_callprojs.fallthrough_catchproj, ctrl);
1521     _igvn.remove_dead_node(_callprojs.fallthrough_catchproj);
1522   }
1523   if (_callprojs.catchall_catchproj != NULL) {
1524     _igvn.rehash_node_delayed(_callprojs.catchall_catchproj);
1525     _callprojs.catchall_catchproj->set_req(0, top());
1526   }
1527   if (_callprojs.fallthrough_proj != NULL) {
1528     Node* catchnode = _callprojs.fallthrough_proj->unique_ctrl_out();
1529     _igvn.remove_dead_node(catchnode);
1530     _igvn.remove_dead_node(_callprojs.fallthrough_proj);
1531   }
1532   if (_callprojs.fallthrough_memproj != NULL) {
1533     migrate_outs(_callprojs.fallthrough_memproj, mem);
1534     _igvn.remove_dead_node(_callprojs.fallthrough_memproj);
1535   }
1536   if (_callprojs.fallthrough_ioproj != NULL) {
1537     migrate_outs(_callprojs.fallthrough_ioproj, i_o);
1538     _igvn.remove_dead_node(_callprojs.fallthrough_ioproj);
1539   }
1540   if (_callprojs.catchall_memproj != NULL) {
1541     _igvn.rehash_node_delayed(_callprojs.catchall_memproj);
1542     _callprojs.catchall_memproj->set_req(0, top());
1543   }
1544   if (_callprojs.catchall_ioproj != NULL) {
1545     _igvn.rehash_node_delayed(_callprojs.catchall_ioproj);
1546     _callprojs.catchall_ioproj->set_req(0, top());
1547   }
1548 #ifndef PRODUCT
1549   if (PrintEliminateAllocations) {
1550     if (alloc->is_AllocateArray()) {
1551       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1552     } else {
1553       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1554     }
1555   }
1556 #endif
1557   _igvn.remove_dead_node(alloc);
1558 }
1559 
1560 void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
1561                                                 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
1562   // If initialization is performed by an array copy, any required
1563   // MemBarStoreStore was already added. If the object does not
1564   // escape no need for a MemBarStoreStore. If the object does not
1565   // escape in its initializer and memory barrier (MemBarStoreStore or
1566   // stronger) is already added at exit of initializer, also no need
1567   // for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
1568   // so that stores that initialize this object can't be reordered
1569   // with a subsequent store that makes this object accessible by
1570   // other threads.
1571   // Other threads include java threads and JVM internal threads
1572   // (for example concurrent GC threads). Current concurrent GC
1573   // implementation: G1 will not scan newly created object,
1574   // so it's safe to skip storestore barrier when allocation does
1575   // not escape.
1576   if (!alloc->does_not_escape_thread() &&
1577     !alloc->is_allocation_MemBar_redundant() &&
1578     (init == NULL || !init->is_complete_with_arraycopy())) {
1579     if (init == NULL || init->req() < InitializeNode::RawStores) {
1580       // No InitializeNode or no stores captured by zeroing
1581       // elimination. Simply add the MemBarStoreStore after object
1582       // initialization.
1583       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1584       transform_later(mb);
1585 
1586       mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
1587       mb->init_req(TypeFunc::Control, fast_oop_ctrl);
1588       fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
1589       transform_later(fast_oop_ctrl);
1590       fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
1591       transform_later(fast_oop_rawmem);
1592     } else {
1593       // Add the MemBarStoreStore after the InitializeNode so that
1594       // all stores performing the initialization that were moved
1595       // before the InitializeNode happen before the storestore
1596       // barrier.
1597 
1598       Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
1599       Node* init_mem = init->proj_out_or_null(TypeFunc::Memory);
1600 
1601       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1602       transform_later(mb);
1603 
1604       Node* ctrl = new ProjNode(init, TypeFunc::Control);
1605       transform_later(ctrl);
1606       Node* mem = new ProjNode(init, TypeFunc::Memory);
1607       transform_later(mem);
1608 
1609       // The MemBarStoreStore depends on control and memory coming
1610       // from the InitializeNode
1611       mb->init_req(TypeFunc::Memory, mem);
1612       mb->init_req(TypeFunc::Control, ctrl);
1613 
1614       ctrl = new ProjNode(mb, TypeFunc::Control);
1615       transform_later(ctrl);
1616       mem = new ProjNode(mb, TypeFunc::Memory);
1617       transform_later(mem);
1618 
1619       // All nodes that depended on the InitializeNode for control
1620       // and memory must now depend on the MemBarNode that itself
1621       // depends on the InitializeNode
1622       if (init_ctrl != NULL) {
1623         _igvn.replace_node(init_ctrl, ctrl);
1624       }
1625       if (init_mem != NULL) {
1626         _igvn.replace_node(init_mem, mem);
1627       }
1628     }
1629   }
1630 }
1631 
1632 void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
1633                                                 Node*& ctrl, Node*& rawmem) {
1634   if (C->env()->dtrace_extended_probes()) {
1635     // Slow-path call
1636     int size = TypeFunc::Parms + 2;
1637     CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
1638                                           CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_object_alloc_base),
1639                                           "dtrace_object_alloc",
1640                                           TypeRawPtr::BOTTOM);
1641 
1642     // Get base of thread-local storage area
1643     Node* thread = new ThreadLocalNode();
1644     transform_later(thread);
1645 
1646     call->init_req(TypeFunc::Parms + 0, thread);
1647     call->init_req(TypeFunc::Parms + 1, oop);
1648     call->init_req(TypeFunc::Control, ctrl);
1649     call->init_req(TypeFunc::I_O    , top()); // does no i/o
1650     call->init_req(TypeFunc::Memory , ctrl);
1651     call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1652     call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
1653     transform_later(call);
1654     ctrl = new ProjNode(call, TypeFunc::Control);
1655     transform_later(ctrl);
1656     rawmem = new ProjNode(call, TypeFunc::Memory);
1657     transform_later(rawmem);
1658   }
1659 }
1660 
1661 // Helper for PhaseMacroExpand::expand_allocate_common.
1662 // Initializes the newly-allocated storage.
1663 Node*
1664 PhaseMacroExpand::initialize_object(AllocateNode* alloc,
1665                                     Node* control, Node* rawmem, Node* object,
1666                                     Node* klass_node, Node* length,
1667                                     Node* size_in_bytes) {
1668   InitializeNode* init = alloc->initialization();
1669   // Store the klass & mark bits
1670   Node* mark_node = alloc->make_ideal_mark(&_igvn, object, control, rawmem);
1671   if (!mark_node->is_Con()) {
1672     transform_later(mark_node);
1673   }
1674   rawmem = make_store(control, rawmem, object, oopDesc::mark_offset_in_bytes(), mark_node, TypeX_X->basic_type());
1675 
1676   rawmem = make_store(control, rawmem, object, oopDesc::klass_offset_in_bytes(), klass_node, T_METADATA);
1677   int header_size = alloc->minimum_header_size();  // conservatively small
1678 
1679   // Array length
1680   if (length != NULL) {         // Arrays need length field
1681     rawmem = make_store(control, rawmem, object, arrayOopDesc::length_offset_in_bytes(), length, T_INT);
1682     // conservatively small header size:
1683     header_size = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1684     ciKlass* k = _igvn.type(klass_node)->is_klassptr()->klass();
1685     if (k->is_array_klass())    // we know the exact header size in most cases:
1686       header_size = Klass::layout_helper_header_size(k->layout_helper());
1687   }
1688 
1689   // Clear the object body, if necessary.
1690   if (init == NULL) {
1691     // The init has somehow disappeared; be cautious and clear everything.
1692     //
1693     // This can happen if a node is allocated but an uncommon trap occurs
1694     // immediately.  In this case, the Initialize gets associated with the
1695     // trap, and may be placed in a different (outer) loop, if the Allocate
1696     // is in a loop.  If (this is rare) the inner loop gets unrolled, then
1697     // there can be two Allocates to one Initialize.  The answer in all these
1698     // edge cases is safety first.  It is always safe to clear immediately
1699     // within an Allocate, and then (maybe or maybe not) clear some more later.
1700     if (!(UseTLAB && ZeroTLAB)) {
1701       rawmem = ClearArrayNode::clear_memory(control, rawmem, object,
1702                                             header_size, size_in_bytes,
1703                                             &_igvn);
1704     }
1705   } else {
1706     if (!init->is_complete()) {
1707       // Try to win by zeroing only what the init does not store.
1708       // We can also try to do some peephole optimizations,
1709       // such as combining some adjacent subword stores.
1710       rawmem = init->complete_stores(control, rawmem, object,
1711                                      header_size, size_in_bytes, &_igvn);
1712     }
1713     // We have no more use for this link, since the AllocateNode goes away:
1714     init->set_req(InitializeNode::RawAddress, top());
1715     // (If we keep the link, it just confuses the register allocator,
1716     // who thinks he sees a real use of the address by the membar.)
1717   }
1718 
1719   return rawmem;
1720 }
1721 
1722 // Generate prefetch instructions for next allocations.
1723 Node* PhaseMacroExpand::prefetch_allocation(Node* i_o, Node*& needgc_false,
1724                                         Node*& contended_phi_rawmem,
1725                                         Node* old_eden_top, Node* new_eden_top,
1726                                         intx lines) {
1727    enum { fall_in_path = 1, pf_path = 2 };
1728    if( UseTLAB && AllocatePrefetchStyle == 2 ) {
1729       // Generate prefetch allocation with watermark check.
1730       // As an allocation hits the watermark, we will prefetch starting
1731       // at a "distance" away from watermark.
1732 
1733       Node *pf_region = new RegionNode(3);
1734       Node *pf_phi_rawmem = new PhiNode( pf_region, Type::MEMORY,
1735                                                 TypeRawPtr::BOTTOM );
1736       // I/O is used for Prefetch
1737       Node *pf_phi_abio = new PhiNode( pf_region, Type::ABIO );
1738 
1739       Node *thread = new ThreadLocalNode();
1740       transform_later(thread);
1741 
1742       Node *eden_pf_adr = new AddPNode( top()/*not oop*/, thread,
1743                    _igvn.MakeConX(in_bytes(JavaThread::tlab_pf_top_offset())) );
1744       transform_later(eden_pf_adr);
1745 
1746       Node *old_pf_wm = new LoadPNode(needgc_false,
1747                                    contended_phi_rawmem, eden_pf_adr,
1748                                    TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,
1749                                    MemNode::unordered);
1750       transform_later(old_pf_wm);
1751 
1752       // check against new_eden_top
1753       Node *need_pf_cmp = new CmpPNode( new_eden_top, old_pf_wm );
1754       transform_later(need_pf_cmp);
1755       Node *need_pf_bol = new BoolNode( need_pf_cmp, BoolTest::ge );
1756       transform_later(need_pf_bol);
1757       IfNode *need_pf_iff = new IfNode( needgc_false, need_pf_bol,
1758                                        PROB_UNLIKELY_MAG(4), COUNT_UNKNOWN );
1759       transform_later(need_pf_iff);
1760 
1761       // true node, add prefetchdistance
1762       Node *need_pf_true = new IfTrueNode( need_pf_iff );
1763       transform_later(need_pf_true);
1764 
1765       Node *need_pf_false = new IfFalseNode( need_pf_iff );
1766       transform_later(need_pf_false);
1767 
1768       Node *new_pf_wmt = new AddPNode( top(), old_pf_wm,
1769                                     _igvn.MakeConX(AllocatePrefetchDistance) );
1770       transform_later(new_pf_wmt );
1771       new_pf_wmt->set_req(0, need_pf_true);
1772 
1773       Node *store_new_wmt = new StorePNode(need_pf_true,
1774                                        contended_phi_rawmem, eden_pf_adr,
1775                                        TypeRawPtr::BOTTOM, new_pf_wmt,
1776                                        MemNode::unordered);
1777       transform_later(store_new_wmt);
1778 
1779       // adding prefetches
1780       pf_phi_abio->init_req( fall_in_path, i_o );
1781 
1782       Node *prefetch_adr;
1783       Node *prefetch;
1784       uint step_size = AllocatePrefetchStepSize;
1785       uint distance = 0;
1786 
1787       for ( intx i = 0; i < lines; i++ ) {
1788         prefetch_adr = new AddPNode( old_pf_wm, new_pf_wmt,
1789                                             _igvn.MakeConX(distance) );
1790         transform_later(prefetch_adr);
1791         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1792         transform_later(prefetch);
1793         distance += step_size;
1794         i_o = prefetch;
1795       }
1796       pf_phi_abio->set_req( pf_path, i_o );
1797 
1798       pf_region->init_req( fall_in_path, need_pf_false );
1799       pf_region->init_req( pf_path, need_pf_true );
1800 
1801       pf_phi_rawmem->init_req( fall_in_path, contended_phi_rawmem );
1802       pf_phi_rawmem->init_req( pf_path, store_new_wmt );
1803 
1804       transform_later(pf_region);
1805       transform_later(pf_phi_rawmem);
1806       transform_later(pf_phi_abio);
1807 
1808       needgc_false = pf_region;
1809       contended_phi_rawmem = pf_phi_rawmem;
1810       i_o = pf_phi_abio;
1811    } else if( UseTLAB && AllocatePrefetchStyle == 3 ) {
1812       // Insert a prefetch instruction for each allocation.
1813       // This code is used to generate 1 prefetch instruction per cache line.
1814 
1815       // Generate several prefetch instructions.
1816       uint step_size = AllocatePrefetchStepSize;
1817       uint distance = AllocatePrefetchDistance;
1818 
1819       // Next cache address.
1820       Node *cache_adr = new AddPNode(old_eden_top, old_eden_top,
1821                                      _igvn.MakeConX(step_size + distance));
1822       transform_later(cache_adr);
1823       cache_adr = new CastP2XNode(needgc_false, cache_adr);
1824       transform_later(cache_adr);
1825       // Address is aligned to execute prefetch to the beginning of cache line size
1826       // (it is important when BIS instruction is used on SPARC as prefetch).
1827       Node* mask = _igvn.MakeConX(~(intptr_t)(step_size-1));
1828       cache_adr = new AndXNode(cache_adr, mask);
1829       transform_later(cache_adr);
1830       cache_adr = new CastX2PNode(cache_adr);
1831       transform_later(cache_adr);
1832 
1833       // Prefetch
1834       Node *prefetch = new PrefetchAllocationNode( contended_phi_rawmem, cache_adr );
1835       prefetch->set_req(0, needgc_false);
1836       transform_later(prefetch);
1837       contended_phi_rawmem = prefetch;
1838       Node *prefetch_adr;
1839       distance = step_size;
1840       for ( intx i = 1; i < lines; i++ ) {
1841         prefetch_adr = new AddPNode( cache_adr, cache_adr,
1842                                             _igvn.MakeConX(distance) );
1843         transform_later(prefetch_adr);
1844         prefetch = new PrefetchAllocationNode( contended_phi_rawmem, prefetch_adr );
1845         transform_later(prefetch);
1846         distance += step_size;
1847         contended_phi_rawmem = prefetch;
1848       }
1849    } else if( AllocatePrefetchStyle > 0 ) {
1850       // Insert a prefetch for each allocation only on the fast-path
1851       Node *prefetch_adr;
1852       Node *prefetch;
1853       // Generate several prefetch instructions.
1854       uint step_size = AllocatePrefetchStepSize;
1855       uint distance = AllocatePrefetchDistance;
1856       for ( intx i = 0; i < lines; i++ ) {
1857         prefetch_adr = new AddPNode( old_eden_top, new_eden_top,
1858                                             _igvn.MakeConX(distance) );
1859         transform_later(prefetch_adr);
1860         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1861         // Do not let it float too high, since if eden_top == eden_end,
1862         // both might be null.
1863         if( i == 0 ) { // Set control for first prefetch, next follows it
1864           prefetch->init_req(0, needgc_false);
1865         }
1866         transform_later(prefetch);
1867         distance += step_size;
1868         i_o = prefetch;
1869       }
1870    }
1871    return i_o;
1872 }
1873 
1874 
1875 void PhaseMacroExpand::expand_allocate(AllocateNode *alloc) {
1876   expand_allocate_common(alloc, NULL,
1877                          OptoRuntime::new_instance_Type(),
1878                          OptoRuntime::new_instance_Java());
1879 }
1880 
1881 void PhaseMacroExpand::expand_allocate_array(AllocateArrayNode *alloc) {
1882   Node* length = alloc->in(AllocateNode::ALength);
1883   InitializeNode* init = alloc->initialization();
1884   Node* klass_node = alloc->in(AllocateNode::KlassNode);
1885   ciKlass* k = _igvn.type(klass_node)->is_klassptr()->klass();
1886   address slow_call_address;  // Address of slow call
1887   if (init != NULL && init->is_complete_with_arraycopy() &&
1888       k->is_type_array_klass()) {
1889     // Don't zero type array during slow allocation in VM since
1890     // it will be initialized later by arraycopy in compiled code.
1891     slow_call_address = OptoRuntime::new_array_nozero_Java();
1892   } else {
1893     slow_call_address = OptoRuntime::new_array_Java();
1894   }
1895   expand_allocate_common(alloc, length,
1896                          OptoRuntime::new_array_Type(),
1897                          slow_call_address);
1898 }
1899 
1900 //-------------------mark_eliminated_box----------------------------------
1901 //
1902 // During EA obj may point to several objects but after few ideal graph
1903 // transformations (CCP) it may point to only one non escaping object
1904 // (but still using phi), corresponding locks and unlocks will be marked
1905 // for elimination. Later obj could be replaced with a new node (new phi)
1906 // and which does not have escape information. And later after some graph
1907 // reshape other locks and unlocks (which were not marked for elimination
1908 // before) are connected to this new obj (phi) but they still will not be
1909 // marked for elimination since new obj has no escape information.
1910 // Mark all associated (same box and obj) lock and unlock nodes for
1911 // elimination if some of them marked already.
1912 void PhaseMacroExpand::mark_eliminated_box(Node* oldbox, Node* obj) {
1913   if (oldbox->as_BoxLock()->is_eliminated()) {
1914     return; // This BoxLock node was processed already.
1915   }
1916   // New implementation (EliminateNestedLocks) has separate BoxLock
1917   // node for each locked region so mark all associated locks/unlocks as
1918   // eliminated even if different objects are referenced in one locked region
1919   // (for example, OSR compilation of nested loop inside locked scope).
1920   if (EliminateNestedLocks ||
1921       oldbox->as_BoxLock()->is_simple_lock_region(NULL, obj, NULL)) {
1922     // Box is used only in one lock region. Mark this box as eliminated.
1923     _igvn.hash_delete(oldbox);
1924     oldbox->as_BoxLock()->set_eliminated(); // This changes box's hash value
1925      _igvn.hash_insert(oldbox);
1926 
1927     for (uint i = 0; i < oldbox->outcnt(); i++) {
1928       Node* u = oldbox->raw_out(i);
1929       if (u->is_AbstractLock() && !u->as_AbstractLock()->is_non_esc_obj()) {
1930         AbstractLockNode* alock = u->as_AbstractLock();
1931         // Check lock's box since box could be referenced by Lock's debug info.
1932         if (alock->box_node() == oldbox) {
1933           // Mark eliminated all related locks and unlocks.
1934 #ifdef ASSERT
1935           alock->log_lock_optimization(C, "eliminate_lock_set_non_esc4");
1936 #endif
1937           alock->set_non_esc_obj();
1938         }
1939       }
1940     }
1941     return;
1942   }
1943 
1944   // Create new "eliminated" BoxLock node and use it in monitor debug info
1945   // instead of oldbox for the same object.
1946   BoxLockNode* newbox = oldbox->clone()->as_BoxLock();
1947 
1948   // Note: BoxLock node is marked eliminated only here and it is used
1949   // to indicate that all associated lock and unlock nodes are marked
1950   // for elimination.
1951   newbox->set_eliminated();
1952   transform_later(newbox);
1953 
1954   // Replace old box node with new box for all users of the same object.
1955   for (uint i = 0; i < oldbox->outcnt();) {
1956     bool next_edge = true;
1957 
1958     Node* u = oldbox->raw_out(i);
1959     if (u->is_AbstractLock()) {
1960       AbstractLockNode* alock = u->as_AbstractLock();
1961       if (alock->box_node() == oldbox && alock->obj_node()->eqv_uncast(obj)) {
1962         // Replace Box and mark eliminated all related locks and unlocks.
1963 #ifdef ASSERT
1964         alock->log_lock_optimization(C, "eliminate_lock_set_non_esc5");
1965 #endif
1966         alock->set_non_esc_obj();
1967         _igvn.rehash_node_delayed(alock);
1968         alock->set_box_node(newbox);
1969         next_edge = false;
1970       }
1971     }
1972     if (u->is_FastLock() && u->as_FastLock()->obj_node()->eqv_uncast(obj)) {
1973       FastLockNode* flock = u->as_FastLock();
1974       assert(flock->box_node() == oldbox, "sanity");
1975       _igvn.rehash_node_delayed(flock);
1976       flock->set_box_node(newbox);
1977       next_edge = false;
1978     }
1979 
1980     // Replace old box in monitor debug info.
1981     if (u->is_SafePoint() && u->as_SafePoint()->jvms()) {
1982       SafePointNode* sfn = u->as_SafePoint();
1983       JVMState* youngest_jvms = sfn->jvms();
1984       int max_depth = youngest_jvms->depth();
1985       for (int depth = 1; depth <= max_depth; depth++) {
1986         JVMState* jvms = youngest_jvms->of_depth(depth);
1987         int num_mon  = jvms->nof_monitors();
1988         // Loop over monitors
1989         for (int idx = 0; idx < num_mon; idx++) {
1990           Node* obj_node = sfn->monitor_obj(jvms, idx);
1991           Node* box_node = sfn->monitor_box(jvms, idx);
1992           if (box_node == oldbox && obj_node->eqv_uncast(obj)) {
1993             int j = jvms->monitor_box_offset(idx);
1994             _igvn.replace_input_of(u, j, newbox);
1995             next_edge = false;
1996           }
1997         }
1998       }
1999     }
2000     if (next_edge) i++;
2001   }
2002 }
2003 
2004 //-----------------------mark_eliminated_locking_nodes-----------------------
2005 void PhaseMacroExpand::mark_eliminated_locking_nodes(AbstractLockNode *alock) {
2006   if (EliminateNestedLocks) {
2007     if (alock->is_nested()) {
2008        assert(alock->box_node()->as_BoxLock()->is_eliminated(), "sanity");
2009        return;
2010     } else if (!alock->is_non_esc_obj()) { // Not eliminated or coarsened
2011       // Only Lock node has JVMState needed here.
2012       // Not that preceding claim is documented anywhere else.
2013       if (alock->jvms() != NULL) {
2014         if (alock->as_Lock()->is_nested_lock_region()) {
2015           // Mark eliminated related nested locks and unlocks.
2016           Node* obj = alock->obj_node();
2017           BoxLockNode* box_node = alock->box_node()->as_BoxLock();
2018           assert(!box_node->is_eliminated(), "should not be marked yet");
2019           // Note: BoxLock node is marked eliminated only here
2020           // and it is used to indicate that all associated lock
2021           // and unlock nodes are marked for elimination.
2022           box_node->set_eliminated(); // Box's hash is always NO_HASH here
2023           for (uint i = 0; i < box_node->outcnt(); i++) {
2024             Node* u = box_node->raw_out(i);
2025             if (u->is_AbstractLock()) {
2026               alock = u->as_AbstractLock();
2027               if (alock->box_node() == box_node) {
2028                 // Verify that this Box is referenced only by related locks.
2029                 assert(alock->obj_node()->eqv_uncast(obj), "");
2030                 // Mark all related locks and unlocks.
2031 #ifdef ASSERT
2032                 alock->log_lock_optimization(C, "eliminate_lock_set_nested");
2033 #endif
2034                 alock->set_nested();
2035               }
2036             }
2037           }
2038         } else {
2039 #ifdef ASSERT
2040           alock->log_lock_optimization(C, "eliminate_lock_NOT_nested_lock_region");
2041           if (C->log() != NULL)
2042             alock->as_Lock()->is_nested_lock_region(C); // rerun for debugging output
2043 #endif
2044         }
2045       }
2046       return;
2047     }
2048     // Process locks for non escaping object
2049     assert(alock->is_non_esc_obj(), "");
2050   } // EliminateNestedLocks
2051 
2052   if (alock->is_non_esc_obj()) { // Lock is used for non escaping object
2053     // Look for all locks of this object and mark them and
2054     // corresponding BoxLock nodes as eliminated.
2055     Node* obj = alock->obj_node();
2056     for (uint j = 0; j < obj->outcnt(); j++) {
2057       Node* o = obj->raw_out(j);
2058       if (o->is_AbstractLock() &&
2059           o->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
2060         alock = o->as_AbstractLock();
2061         Node* box = alock->box_node();
2062         // Replace old box node with new eliminated box for all users
2063         // of the same object and mark related locks as eliminated.
2064         mark_eliminated_box(box, obj);
2065       }
2066     }
2067   }
2068 }
2069 
2070 // we have determined that this lock/unlock can be eliminated, we simply
2071 // eliminate the node without expanding it.
2072 //
2073 // Note:  The membar's associated with the lock/unlock are currently not
2074 //        eliminated.  This should be investigated as a future enhancement.
2075 //
2076 bool PhaseMacroExpand::eliminate_locking_node(AbstractLockNode *alock) {
2077 
2078   if (!alock->is_eliminated()) {
2079     return false;
2080   }
2081 #ifdef ASSERT
2082   if (!alock->is_coarsened()) {
2083     // Check that new "eliminated" BoxLock node is created.
2084     BoxLockNode* oldbox = alock->box_node()->as_BoxLock();
2085     assert(oldbox->is_eliminated(), "should be done already");
2086   }
2087 #endif
2088 
2089   alock->log_lock_optimization(C, "eliminate_lock");
2090 
2091 #ifndef PRODUCT
2092   if (PrintEliminateLocks) {
2093     tty->print_cr("++++ Eliminated: %d %s '%s'", alock->_idx, (alock->is_Lock() ? "Lock" : "Unlock"), alock->kind_as_string());
2094   }
2095 #endif
2096 
2097   Node* mem  = alock->in(TypeFunc::Memory);
2098   Node* ctrl = alock->in(TypeFunc::Control);
2099   guarantee(ctrl != NULL, "missing control projection, cannot replace_node() with NULL");
2100 
2101   alock->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2102   // There are 2 projections from the lock.  The lock node will
2103   // be deleted when its last use is subsumed below.
2104   assert(alock->outcnt() == 2 &&
2105          _callprojs.fallthrough_proj != NULL &&
2106          _callprojs.fallthrough_memproj != NULL,
2107          "Unexpected projections from Lock/Unlock");
2108 
2109   Node* fallthroughproj = _callprojs.fallthrough_proj;
2110   Node* memproj_fallthrough = _callprojs.fallthrough_memproj;
2111 
2112   // The memory projection from a lock/unlock is RawMem
2113   // The input to a Lock is merged memory, so extract its RawMem input
2114   // (unless the MergeMem has been optimized away.)
2115   if (alock->is_Lock()) {
2116     // Seach for MemBarAcquireLock node and delete it also.
2117     MemBarNode* membar = fallthroughproj->unique_ctrl_out()->as_MemBar();
2118     assert(membar != NULL && membar->Opcode() == Op_MemBarAcquireLock, "");
2119     Node* ctrlproj = membar->proj_out(TypeFunc::Control);
2120     Node* memproj = membar->proj_out(TypeFunc::Memory);
2121     _igvn.replace_node(ctrlproj, fallthroughproj);
2122     _igvn.replace_node(memproj, memproj_fallthrough);
2123 
2124     // Delete FastLock node also if this Lock node is unique user
2125     // (a loop peeling may clone a Lock node).
2126     Node* flock = alock->as_Lock()->fastlock_node();
2127     if (flock->outcnt() == 1) {
2128       assert(flock->unique_out() == alock, "sanity");
2129       _igvn.replace_node(flock, top());
2130     }
2131   }
2132 
2133   // Seach for MemBarReleaseLock node and delete it also.
2134   if (alock->is_Unlock() && ctrl->is_Proj() && ctrl->in(0)->is_MemBar()) {
2135     MemBarNode* membar = ctrl->in(0)->as_MemBar();
2136     assert(membar->Opcode() == Op_MemBarReleaseLock &&
2137            mem->is_Proj() && membar == mem->in(0), "");
2138     _igvn.replace_node(fallthroughproj, ctrl);
2139     _igvn.replace_node(memproj_fallthrough, mem);
2140     fallthroughproj = ctrl;
2141     memproj_fallthrough = mem;
2142     ctrl = membar->in(TypeFunc::Control);
2143     mem  = membar->in(TypeFunc::Memory);
2144   }
2145 
2146   _igvn.replace_node(fallthroughproj, ctrl);
2147   _igvn.replace_node(memproj_fallthrough, mem);
2148   return true;
2149 }
2150 
2151 
2152 //------------------------------expand_lock_node----------------------
2153 void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
2154 
2155   Node* ctrl = lock->in(TypeFunc::Control);
2156   Node* mem = lock->in(TypeFunc::Memory);
2157   Node* obj = lock->obj_node();
2158   Node* box = lock->box_node();
2159   Node* flock = lock->fastlock_node();
2160 
2161   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2162 
2163   // Make the merge point
2164   Node *region;
2165   Node *mem_phi;
2166   Node *slow_path;
2167 
2168   region  = new RegionNode(3);
2169   // create a Phi for the memory state
2170   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2171 
2172   // Optimize test; set region slot 2
2173   slow_path = opt_bits_test(ctrl, region, 2, flock, 0, 0);
2174   mem_phi->init_req(2, mem);
2175 
2176   // Make slow path call
2177   CallNode *call = make_slow_call((CallNode *) lock, OptoRuntime::complete_monitor_enter_Type(),
2178                                   OptoRuntime::complete_monitor_locking_Java(), NULL, slow_path,
2179                                   obj, box, NULL);
2180 
2181   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2182 
2183   // Slow path can only throw asynchronous exceptions, which are always
2184   // de-opted.  So the compiler thinks the slow-call can never throw an
2185   // exception.  If it DOES throw an exception we would need the debug
2186   // info removed first (since if it throws there is no monitor).
2187   assert(_callprojs.fallthrough_ioproj == NULL && _callprojs.catchall_ioproj == NULL &&
2188          _callprojs.catchall_memproj == NULL && _callprojs.catchall_catchproj == NULL, "Unexpected projection from Lock");
2189 
2190   // Capture slow path
2191   // disconnect fall-through projection from call and create a new one
2192   // hook up users of fall-through projection to region
2193   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2194   transform_later(slow_ctrl);
2195   _igvn.hash_delete(_callprojs.fallthrough_proj);
2196   _callprojs.fallthrough_proj->disconnect_inputs(C);
2197   region->init_req(1, slow_ctrl);
2198   // region inputs are now complete
2199   transform_later(region);
2200   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2201 
2202   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2203 
2204   // held_monitor_count increased in slowpath (complete_monitor_locking_C_inc_held_monitor_count), need compensate a decreament here
2205   // this minimizes control flow changes here and add redundant count updates only in slowpath
2206   Node* thread = transform_later(new ThreadLocalNode());
2207   Node* dec_count = make_load(slow_ctrl, memproj, thread, in_bytes(JavaThread::held_monitor_count_offset()), TypeInt::INT, TypeInt::INT->basic_type());
2208   Node* new_dec_count = transform_later(new SubINode(dec_count, intcon(1)));
2209   Node *compensate_dec = make_store(slow_ctrl, memproj, thread, in_bytes(JavaThread::held_monitor_count_offset()), new_dec_count, T_INT);
2210   mem_phi->init_req(1, compensate_dec);
2211   transform_later(mem_phi);
2212 
2213   // held_monitor_count increases in all path's post-dominate
2214   Node* inc_count = make_load(region, mem_phi, thread, in_bytes(JavaThread::held_monitor_count_offset()), TypeInt::INT, TypeInt::INT->basic_type());
2215   Node* new_inc_count = transform_later(new AddINode(inc_count, intcon(1)));
2216   Node *store = make_store(region, mem_phi, thread, in_bytes(JavaThread::held_monitor_count_offset()), new_inc_count, T_INT);
2217 
2218   _igvn.replace_node(_callprojs.fallthrough_memproj, store);
2219 }
2220 
2221 //------------------------------expand_unlock_node----------------------
2222 void PhaseMacroExpand::expand_unlock_node(UnlockNode *unlock) {
2223 
2224   Node* ctrl = unlock->in(TypeFunc::Control);
2225   Node* mem = unlock->in(TypeFunc::Memory);
2226   Node* obj = unlock->obj_node();
2227   Node* box = unlock->box_node();
2228 
2229   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2230 
2231   // No need for a null check on unlock
2232 
2233   // Make the merge point
2234   Node *region;
2235   Node *mem_phi;
2236 
2237   region  = new RegionNode(3);
2238   // create a Phi for the memory state
2239   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2240 
2241   FastUnlockNode *funlock = new FastUnlockNode( ctrl, obj, box );
2242   funlock = transform_later( funlock )->as_FastUnlock();
2243   // Optimize test; set region slot 2
2244   Node *slow_path = opt_bits_test(ctrl, region, 2, funlock, 0, 0);
2245   Node *thread = transform_later(new ThreadLocalNode());
2246 
2247   CallNode *call = make_slow_call((CallNode *) unlock, OptoRuntime::complete_monitor_exit_Type(),
2248                                   CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C),
2249                                   "complete_monitor_unlocking_C", slow_path, obj, box, thread);
2250 
2251   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2252   assert(_callprojs.fallthrough_ioproj == NULL && _callprojs.catchall_ioproj == NULL &&
2253          _callprojs.catchall_memproj == NULL && _callprojs.catchall_catchproj == NULL, "Unexpected projection from Lock");
2254 
2255   // No exceptions for unlocking
2256   // Capture slow path
2257   // disconnect fall-through projection from call and create a new one
2258   // hook up users of fall-through projection to region
2259   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2260   transform_later(slow_ctrl);
2261   _igvn.hash_delete(_callprojs.fallthrough_proj);
2262   _callprojs.fallthrough_proj->disconnect_inputs(C);
2263   region->init_req(1, slow_ctrl);
2264   // region inputs are now complete
2265   transform_later(region);
2266   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2267 
2268   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory) );
2269   mem_phi->init_req(1, memproj );
2270   mem_phi->init_req(2, mem);
2271   transform_later(mem_phi);
2272 
2273   Node* count = make_load(region, mem_phi, thread, in_bytes(JavaThread::held_monitor_count_offset()), TypeInt::INT, TypeInt::INT->basic_type());
2274   Node* newcount = transform_later(new SubINode(count, intcon(1)));
2275   Node *store = make_store(region, mem_phi, thread, in_bytes(JavaThread::held_monitor_count_offset()), newcount, T_INT);
2276 
2277   _igvn.replace_node(_callprojs.fallthrough_memproj, store);
2278 }
2279 
2280 void PhaseMacroExpand::expand_subtypecheck_node(SubTypeCheckNode *check) {
2281   assert(check->in(SubTypeCheckNode::Control) == NULL, "should be pinned");
2282   Node* bol = check->unique_out();
2283   Node* obj_or_subklass = check->in(SubTypeCheckNode::ObjOrSubKlass);
2284   Node* superklass = check->in(SubTypeCheckNode::SuperKlass);
2285   assert(bol->is_Bool() && bol->as_Bool()->_test._test == BoolTest::ne, "unexpected bool node");
2286 
2287   for (DUIterator_Last imin, i = bol->last_outs(imin); i >= imin; --i) {
2288     Node* iff = bol->last_out(i);
2289     assert(iff->is_If(), "where's the if?");
2290 
2291     if (iff->in(0)->is_top()) {
2292       _igvn.replace_input_of(iff, 1, C->top());
2293       continue;
2294     }
2295 
2296     Node* iftrue = iff->as_If()->proj_out(1);
2297     Node* iffalse = iff->as_If()->proj_out(0);
2298     Node* ctrl = iff->in(0);
2299 
2300     Node* subklass = NULL;
2301     if (_igvn.type(obj_or_subklass)->isa_klassptr()) {
2302       subklass = obj_or_subklass;
2303     } else {
2304       Node* k_adr = basic_plus_adr(obj_or_subklass, oopDesc::klass_offset_in_bytes());
2305       subklass = _igvn.transform(LoadKlassNode::make(_igvn, NULL, C->immutable_memory(), k_adr, TypeInstPtr::KLASS));
2306     }
2307 
2308     Node* not_subtype_ctrl = Phase::gen_subtype_check(subklass, superklass, &ctrl, NULL, _igvn);
2309 
2310     _igvn.replace_input_of(iff, 0, C->top());
2311     _igvn.replace_node(iftrue, not_subtype_ctrl);
2312     _igvn.replace_node(iffalse, ctrl);
2313   }
2314   _igvn.replace_node(check, C->top());
2315 }
2316 
2317 //---------------------------eliminate_macro_nodes----------------------
2318 // Eliminate scalar replaced allocations and associated locks.
2319 void PhaseMacroExpand::eliminate_macro_nodes() {
2320   if (C->macro_count() == 0)
2321     return;
2322 
2323   // Before elimination may re-mark (change to Nested or NonEscObj)
2324   // all associated (same box and obj) lock and unlock nodes.
2325   int cnt = C->macro_count();
2326   for (int i=0; i < cnt; i++) {
2327     Node *n = C->macro_node(i);
2328     if (n->is_AbstractLock()) { // Lock and Unlock nodes
2329       mark_eliminated_locking_nodes(n->as_AbstractLock());
2330     }
2331   }
2332   // Re-marking may break consistency of Coarsened locks.
2333   if (!C->coarsened_locks_consistent()) {
2334     return; // recompile without Coarsened locks if broken
2335   }
2336 
2337   // First, attempt to eliminate locks
2338   bool progress = true;
2339   while (progress) {
2340     progress = false;
2341     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2342       Node* n = C->macro_node(i - 1);
2343       bool success = false;
2344       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2345       if (n->is_AbstractLock()) {
2346         success = eliminate_locking_node(n->as_AbstractLock());
2347       }
2348       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2349       progress = progress || success;
2350     }
2351   }
2352   // Next, attempt to eliminate allocations
2353   _has_locks = false;
2354   progress = true;
2355   while (progress) {
2356     progress = false;
2357     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2358       Node* n = C->macro_node(i - 1);
2359       bool success = false;
2360       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2361       switch (n->class_id()) {
2362       case Node::Class_Allocate:
2363       case Node::Class_AllocateArray:
2364         success = eliminate_allocate_node(n->as_Allocate());
2365         break;
2366       case Node::Class_CallStaticJava:
2367         success = eliminate_boxing_node(n->as_CallStaticJava());
2368         break;
2369       case Node::Class_Lock:
2370       case Node::Class_Unlock:
2371         assert(!n->as_AbstractLock()->is_eliminated(), "sanity");
2372         _has_locks = true;
2373         break;
2374       case Node::Class_ArrayCopy:
2375         break;
2376       case Node::Class_OuterStripMinedLoop:
2377         break;
2378       case Node::Class_SubTypeCheck:
2379         break;
2380       case Node::Class_Opaque1:
2381         break;
2382       default:
2383         assert(n->Opcode() == Op_LoopLimit ||
2384                n->Opcode() == Op_Opaque2   ||
2385                n->Opcode() == Op_Opaque3   ||
2386                BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(n),
2387                "unknown node type in macro list");
2388       }
2389       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2390       progress = progress || success;
2391     }
2392   }
2393 }
2394 
2395 //------------------------------expand_macro_nodes----------------------
2396 //  Returns true if a failure occurred.
2397 bool PhaseMacroExpand::expand_macro_nodes() {
2398   // Last attempt to eliminate macro nodes.
2399   eliminate_macro_nodes();
2400   if (C->failing())  return true;
2401 
2402   // Eliminate Opaque and LoopLimit nodes. Do it after all loop optimizations.
2403   bool progress = true;
2404   while (progress) {
2405     progress = false;
2406     for (int i = C->macro_count(); i > 0; i--) {
2407       Node* n = C->macro_node(i-1);
2408       bool success = false;
2409       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2410       if (n->Opcode() == Op_LoopLimit) {
2411         // Remove it from macro list and put on IGVN worklist to optimize.
2412         C->remove_macro_node(n);
2413         _igvn._worklist.push(n);
2414         success = true;
2415       } else if (n->Opcode() == Op_CallStaticJava) {
2416         // Remove it from macro list and put on IGVN worklist to optimize.
2417         C->remove_macro_node(n);
2418         _igvn._worklist.push(n);
2419         success = true;
2420       } else if (n->is_Opaque1() || n->Opcode() == Op_Opaque2) {
2421         _igvn.replace_node(n, n->in(1));
2422         success = true;
2423 #if INCLUDE_RTM_OPT
2424       } else if ((n->Opcode() == Op_Opaque3) && ((Opaque3Node*)n)->rtm_opt()) {
2425         assert(C->profile_rtm(), "should be used only in rtm deoptimization code");
2426         assert((n->outcnt() == 1) && n->unique_out()->is_Cmp(), "");
2427         Node* cmp = n->unique_out();
2428 #ifdef ASSERT
2429         // Validate graph.
2430         assert((cmp->outcnt() == 1) && cmp->unique_out()->is_Bool(), "");
2431         BoolNode* bol = cmp->unique_out()->as_Bool();
2432         assert((bol->outcnt() == 1) && bol->unique_out()->is_If() &&
2433                (bol->_test._test == BoolTest::ne), "");
2434         IfNode* ifn = bol->unique_out()->as_If();
2435         assert((ifn->outcnt() == 2) &&
2436                ifn->proj_out(1)->is_uncommon_trap_proj(Deoptimization::Reason_rtm_state_change) != NULL, "");
2437 #endif
2438         Node* repl = n->in(1);
2439         if (!_has_locks) {
2440           // Remove RTM state check if there are no locks in the code.
2441           // Replace input to compare the same value.
2442           repl = (cmp->in(1) == n) ? cmp->in(2) : cmp->in(1);
2443         }
2444         _igvn.replace_node(n, repl);
2445         success = true;
2446 #endif
2447       } else if (n->Opcode() == Op_OuterStripMinedLoop) {
2448         n->as_OuterStripMinedLoop()->adjust_strip_mined_loop(&_igvn);
2449         C->remove_macro_node(n);
2450         success = true;
2451       }
2452       assert(!success || (C->macro_count() == (old_macro_count - 1)), "elimination must have deleted one node from macro list");
2453       progress = progress || success;
2454     }
2455   }
2456 
2457   // Clean up the graph so we're less likely to hit the maximum node
2458   // limit
2459   _igvn.set_delay_transform(false);
2460   _igvn.optimize();
2461   if (C->failing())  return true;
2462   _igvn.set_delay_transform(true);
2463 
2464 
2465   // Because we run IGVN after each expansion, some macro nodes may go
2466   // dead and be removed from the list as we iterate over it. Move
2467   // Allocate nodes (processed in a second pass) at the beginning of
2468   // the list and then iterate from the last element of the list until
2469   // an Allocate node is seen. This is robust to random deletion in
2470   // the list due to nodes going dead.
2471   C->sort_macro_nodes();
2472 
2473   // expand arraycopy "macro" nodes first
2474   // For ReduceBulkZeroing, we must first process all arraycopy nodes
2475   // before the allocate nodes are expanded.
2476   while (C->macro_count() > 0) {
2477     int macro_count = C->macro_count();
2478     Node * n = C->macro_node(macro_count-1);
2479     assert(n->is_macro(), "only macro nodes expected here");
2480     if (_igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())) {
2481       // node is unreachable, so don't try to expand it
2482       C->remove_macro_node(n);
2483       continue;
2484     }
2485     if (n->is_Allocate()) {
2486       break;
2487     }
2488     // Make sure expansion will not cause node limit to be exceeded.
2489     // Worst case is a macro node gets expanded into about 200 nodes.
2490     // Allow 50% more for optimization.
2491     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2492       return true;
2493     }
2494 
2495     DEBUG_ONLY(int old_macro_count = C->macro_count();)
2496     switch (n->class_id()) {
2497     case Node::Class_Lock:
2498       expand_lock_node(n->as_Lock());
2499       break;
2500     case Node::Class_Unlock:
2501       expand_unlock_node(n->as_Unlock());
2502       break;
2503     case Node::Class_ArrayCopy:
2504       expand_arraycopy_node(n->as_ArrayCopy());
2505       break;
2506     case Node::Class_SubTypeCheck:
2507       expand_subtypecheck_node(n->as_SubTypeCheck());
2508       break;
2509     default:
2510       assert(false, "unknown node type in macro list");
2511     }
2512     assert(C->macro_count() == (old_macro_count - 1), "expansion must have deleted one node from macro list");
2513     if (C->failing())  return true;
2514 
2515     // Clean up the graph so we're less likely to hit the maximum node
2516     // limit
2517     _igvn.set_delay_transform(false);
2518     _igvn.optimize();
2519     if (C->failing())  return true;
2520     _igvn.set_delay_transform(true);
2521   }
2522 
2523   // All nodes except Allocate nodes are expanded now. There could be
2524   // new optimization opportunities (such as folding newly created
2525   // load from a just allocated object). Run IGVN.
2526 
2527   // expand "macro" nodes
2528   // nodes are removed from the macro list as they are processed
2529   while (C->macro_count() > 0) {
2530     int macro_count = C->macro_count();
2531     Node * n = C->macro_node(macro_count-1);
2532     assert(n->is_macro(), "only macro nodes expected here");
2533     if (_igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())) {
2534       // node is unreachable, so don't try to expand it
2535       C->remove_macro_node(n);
2536       continue;
2537     }
2538     // Make sure expansion will not cause node limit to be exceeded.
2539     // Worst case is a macro node gets expanded into about 200 nodes.
2540     // Allow 50% more for optimization.
2541     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2542       return true;
2543     }
2544     switch (n->class_id()) {
2545     case Node::Class_Allocate:
2546       expand_allocate(n->as_Allocate());
2547       break;
2548     case Node::Class_AllocateArray:
2549       expand_allocate_array(n->as_AllocateArray());
2550       break;
2551     default:
2552       assert(false, "unknown node type in macro list");
2553     }
2554     assert(C->macro_count() < macro_count, "must have deleted a node from macro list");
2555     if (C->failing())  return true;
2556 
2557     // Clean up the graph so we're less likely to hit the maximum node
2558     // limit
2559     _igvn.set_delay_transform(false);
2560     _igvn.optimize();
2561     if (C->failing())  return true;
2562     _igvn.set_delay_transform(true);
2563   }
2564 
2565   _igvn.set_delay_transform(false);
2566   return false;
2567 }