1 /*
   2  * Copyright (c) 1997, 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 "jvm_io.h"
  27 #include "asm/macroAssembler.hpp"
  28 #include "asm/macroAssembler.inline.hpp"
  29 #include "ci/ciReplay.hpp"
  30 #include "classfile/javaClasses.hpp"
  31 #include "code/exceptionHandlerTable.hpp"
  32 #include "code/nmethod.hpp"
  33 #include "compiler/compileBroker.hpp"
  34 #include "compiler/compileLog.hpp"
  35 #include "compiler/disassembler.hpp"
  36 #include "compiler/oopMap.hpp"
  37 #include "gc/shared/barrierSet.hpp"
  38 #include "gc/shared/c2/barrierSetC2.hpp"
  39 #include "jfr/jfrEvents.hpp"
  40 #include "memory/resourceArea.hpp"
  41 #include "opto/addnode.hpp"
  42 #include "opto/block.hpp"
  43 #include "opto/c2compiler.hpp"
  44 #include "opto/callGenerator.hpp"
  45 #include "opto/callnode.hpp"
  46 #include "opto/castnode.hpp"
  47 #include "opto/cfgnode.hpp"
  48 #include "opto/chaitin.hpp"
  49 #include "opto/compile.hpp"
  50 #include "opto/connode.hpp"
  51 #include "opto/convertnode.hpp"
  52 #include "opto/divnode.hpp"
  53 #include "opto/escape.hpp"
  54 #include "opto/idealGraphPrinter.hpp"
  55 #include "opto/loopnode.hpp"
  56 #include "opto/machnode.hpp"
  57 #include "opto/macro.hpp"
  58 #include "opto/matcher.hpp"
  59 #include "opto/mathexactnode.hpp"
  60 #include "opto/memnode.hpp"
  61 #include "opto/mulnode.hpp"
  62 #include "opto/narrowptrnode.hpp"
  63 #include "opto/node.hpp"
  64 #include "opto/opcodes.hpp"
  65 #include "opto/output.hpp"
  66 #include "opto/parse.hpp"
  67 #include "opto/phaseX.hpp"
  68 #include "opto/rootnode.hpp"
  69 #include "opto/runtime.hpp"
  70 #include "opto/stringopts.hpp"
  71 #include "opto/type.hpp"
  72 #include "opto/vector.hpp"
  73 #include "opto/vectornode.hpp"
  74 #include "runtime/globals_extension.hpp"
  75 #include "runtime/sharedRuntime.hpp"
  76 #include "runtime/signature.hpp"
  77 #include "runtime/stubRoutines.hpp"
  78 #include "runtime/timer.hpp"
  79 #include "utilities/align.hpp"
  80 #include "utilities/copy.hpp"
  81 #include "utilities/macros.hpp"
  82 #include "utilities/resourceHash.hpp"
  83 
  84 
  85 // -------------------- Compile::mach_constant_base_node -----------------------
  86 // Constant table base node singleton.
  87 MachConstantBaseNode* Compile::mach_constant_base_node() {
  88   if (_mach_constant_base_node == NULL) {
  89     _mach_constant_base_node = new MachConstantBaseNode();
  90     _mach_constant_base_node->add_req(C->root());
  91   }
  92   return _mach_constant_base_node;
  93 }
  94 
  95 
  96 /// Support for intrinsics.
  97 
  98 // Return the index at which m must be inserted (or already exists).
  99 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 100 class IntrinsicDescPair {
 101  private:
 102   ciMethod* _m;
 103   bool _is_virtual;
 104  public:
 105   IntrinsicDescPair(ciMethod* m, bool is_virtual) : _m(m), _is_virtual(is_virtual) {}
 106   static int compare(IntrinsicDescPair* const& key, CallGenerator* const& elt) {
 107     ciMethod* m= elt->method();
 108     ciMethod* key_m = key->_m;
 109     if (key_m < m)      return -1;
 110     else if (key_m > m) return 1;
 111     else {
 112       bool is_virtual = elt->is_virtual();
 113       bool key_virtual = key->_is_virtual;
 114       if (key_virtual < is_virtual)      return -1;
 115       else if (key_virtual > is_virtual) return 1;
 116       else                               return 0;
 117     }
 118   }
 119 };
 120 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual, bool& found) {
 121 #ifdef ASSERT
 122   for (int i = 1; i < _intrinsics.length(); i++) {
 123     CallGenerator* cg1 = _intrinsics.at(i-1);
 124     CallGenerator* cg2 = _intrinsics.at(i);
 125     assert(cg1->method() != cg2->method()
 126            ? cg1->method()     < cg2->method()
 127            : cg1->is_virtual() < cg2->is_virtual(),
 128            "compiler intrinsics list must stay sorted");
 129   }
 130 #endif
 131   IntrinsicDescPair pair(m, is_virtual);
 132   return _intrinsics.find_sorted<IntrinsicDescPair*, IntrinsicDescPair::compare>(&pair, found);
 133 }
 134 
 135 void Compile::register_intrinsic(CallGenerator* cg) {
 136   bool found = false;
 137   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual(), found);
 138   assert(!found, "registering twice");
 139   _intrinsics.insert_before(index, cg);
 140   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 141 }
 142 
 143 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 144   assert(m->is_loaded(), "don't try this on unloaded methods");
 145   if (_intrinsics.length() > 0) {
 146     bool found = false;
 147     int index = intrinsic_insertion_index(m, is_virtual, found);
 148      if (found) {
 149       return _intrinsics.at(index);
 150     }
 151   }
 152   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 153   if (m->intrinsic_id() != vmIntrinsics::_none &&
 154       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 155     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 156     if (cg != NULL) {
 157       // Save it for next time:
 158       register_intrinsic(cg);
 159       return cg;
 160     } else {
 161       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 162     }
 163   }
 164   return NULL;
 165 }
 166 
 167 // Compile::make_vm_intrinsic is defined in library_call.cpp.
 168 
 169 #ifndef PRODUCT
 170 // statistics gathering...
 171 
 172 juint  Compile::_intrinsic_hist_count[vmIntrinsics::number_of_intrinsics()] = {0};
 173 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::number_of_intrinsics()] = {0};
 174 
 175 inline int as_int(vmIntrinsics::ID id) {
 176   return vmIntrinsics::as_int(id);
 177 }
 178 
 179 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 180   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 181   int oflags = _intrinsic_hist_flags[as_int(id)];
 182   assert(flags != 0, "what happened?");
 183   if (is_virtual) {
 184     flags |= _intrinsic_virtual;
 185   }
 186   bool changed = (flags != oflags);
 187   if ((flags & _intrinsic_worked) != 0) {
 188     juint count = (_intrinsic_hist_count[as_int(id)] += 1);
 189     if (count == 1) {
 190       changed = true;           // first time
 191     }
 192     // increment the overall count also:
 193     _intrinsic_hist_count[as_int(vmIntrinsics::_none)] += 1;
 194   }
 195   if (changed) {
 196     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 197       // Something changed about the intrinsic's virtuality.
 198       if ((flags & _intrinsic_virtual) != 0) {
 199         // This is the first use of this intrinsic as a virtual call.
 200         if (oflags != 0) {
 201           // We already saw it as a non-virtual, so note both cases.
 202           flags |= _intrinsic_both;
 203         }
 204       } else if ((oflags & _intrinsic_both) == 0) {
 205         // This is the first use of this intrinsic as a non-virtual
 206         flags |= _intrinsic_both;
 207       }
 208     }
 209     _intrinsic_hist_flags[as_int(id)] = (jubyte) (oflags | flags);
 210   }
 211   // update the overall flags also:
 212   _intrinsic_hist_flags[as_int(vmIntrinsics::_none)] |= (jubyte) flags;
 213   return changed;
 214 }
 215 
 216 static char* format_flags(int flags, char* buf) {
 217   buf[0] = 0;
 218   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 219   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 220   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 221   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 222   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 223   if (buf[0] == 0)  strcat(buf, ",");
 224   assert(buf[0] == ',', "must be");
 225   return &buf[1];
 226 }
 227 
 228 void Compile::print_intrinsic_statistics() {
 229   char flagsbuf[100];
 230   ttyLocker ttyl;
 231   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 232   tty->print_cr("Compiler intrinsic usage:");
 233   juint total = _intrinsic_hist_count[as_int(vmIntrinsics::_none)];
 234   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 235   #define PRINT_STAT_LINE(name, c, f) \
 236     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 237   for (auto id : EnumRange<vmIntrinsicID>{}) {
 238     int   flags = _intrinsic_hist_flags[as_int(id)];
 239     juint count = _intrinsic_hist_count[as_int(id)];
 240     if ((flags | count) != 0) {
 241       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 242     }
 243   }
 244   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[as_int(vmIntrinsics::_none)], flagsbuf));
 245   if (xtty != NULL)  xtty->tail("statistics");
 246 }
 247 
 248 void Compile::print_statistics() {
 249   { ttyLocker ttyl;
 250     if (xtty != NULL)  xtty->head("statistics type='opto'");
 251     Parse::print_statistics();
 252     PhaseCCP::print_statistics();
 253     PhaseRegAlloc::print_statistics();
 254     PhaseOutput::print_statistics();
 255     PhasePeephole::print_statistics();
 256     PhaseIdealLoop::print_statistics();
 257     if (xtty != NULL)  xtty->tail("statistics");
 258   }
 259   if (_intrinsic_hist_flags[as_int(vmIntrinsics::_none)] != 0) {
 260     // put this under its own <statistics> element.
 261     print_intrinsic_statistics();
 262   }
 263 }
 264 #endif //PRODUCT
 265 
 266 void Compile::gvn_replace_by(Node* n, Node* nn) {
 267   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 268     Node* use = n->last_out(i);
 269     bool is_in_table = initial_gvn()->hash_delete(use);
 270     uint uses_found = 0;
 271     for (uint j = 0; j < use->len(); j++) {
 272       if (use->in(j) == n) {
 273         if (j < use->req())
 274           use->set_req(j, nn);
 275         else
 276           use->set_prec(j, nn);
 277         uses_found++;
 278       }
 279     }
 280     if (is_in_table) {
 281       // reinsert into table
 282       initial_gvn()->hash_find_insert(use);
 283     }
 284     record_for_igvn(use);
 285     i -= uses_found;    // we deleted 1 or more copies of this edge
 286   }
 287 }
 288 
 289 
 290 // Identify all nodes that are reachable from below, useful.
 291 // Use breadth-first pass that records state in a Unique_Node_List,
 292 // recursive traversal is slower.
 293 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 294   int estimated_worklist_size = live_nodes();
 295   useful.map( estimated_worklist_size, NULL );  // preallocate space
 296 
 297   // Initialize worklist
 298   if (root() != NULL)     { useful.push(root()); }
 299   // If 'top' is cached, declare it useful to preserve cached node
 300   if( cached_top_node() ) { useful.push(cached_top_node()); }
 301 
 302   // Push all useful nodes onto the list, breadthfirst
 303   for( uint next = 0; next < useful.size(); ++next ) {
 304     assert( next < unique(), "Unique useful nodes < total nodes");
 305     Node *n  = useful.at(next);
 306     uint max = n->len();
 307     for( uint i = 0; i < max; ++i ) {
 308       Node *m = n->in(i);
 309       if (not_a_node(m))  continue;
 310       useful.push(m);
 311     }
 312   }
 313 }
 314 
 315 // Update dead_node_list with any missing dead nodes using useful
 316 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 317 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 318   uint max_idx = unique();
 319   VectorSet& useful_node_set = useful.member_set();
 320 
 321   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 322     // If node with index node_idx is not in useful set,
 323     // mark it as dead in dead node list.
 324     if (!useful_node_set.test(node_idx)) {
 325       record_dead_node(node_idx);
 326     }
 327   }
 328 }
 329 
 330 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 331   int shift = 0;
 332   for (int i = 0; i < inlines->length(); i++) {
 333     CallGenerator* cg = inlines->at(i);
 334     if (useful.member(cg->call_node())) {
 335       if (shift > 0) {
 336         inlines->at_put(i - shift, cg);
 337       }
 338     } else {
 339       shift++; // skip over the dead element
 340     }
 341   }
 342   if (shift > 0) {
 343     inlines->trunc_to(inlines->length() - shift); // remove last elements from compacted array
 344   }
 345 }
 346 
 347 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Node* dead) {
 348   assert(dead != NULL && dead->is_Call(), "sanity");
 349   int found = 0;
 350   for (int i = 0; i < inlines->length(); i++) {
 351     if (inlines->at(i)->call_node() == dead) {
 352       inlines->remove_at(i);
 353       found++;
 354       NOT_DEBUG( break; ) // elements are unique, so exit early
 355     }
 356   }
 357   assert(found <= 1, "not unique");
 358 }
 359 
 360 void Compile::remove_useless_nodes(GrowableArray<Node*>& node_list, Unique_Node_List& useful) {
 361   for (int i = node_list.length() - 1; i >= 0; i--) {
 362     Node* n = node_list.at(i);
 363     if (!useful.member(n)) {
 364       node_list.delete_at(i); // replaces i-th with last element which is known to be useful (already processed)
 365     }
 366   }
 367 }
 368 
 369 void Compile::remove_useless_node(Node* dead) {
 370   remove_modified_node(dead);
 371 
 372   // Constant node that has no out-edges and has only one in-edge from
 373   // root is usually dead. However, sometimes reshaping walk makes
 374   // it reachable by adding use edges. So, we will NOT count Con nodes
 375   // as dead to be conservative about the dead node count at any
 376   // given time.
 377   if (!dead->is_Con()) {
 378     record_dead_node(dead->_idx);
 379   }
 380   if (dead->is_macro()) {
 381     remove_macro_node(dead);
 382   }
 383   if (dead->is_expensive()) {
 384     remove_expensive_node(dead);
 385   }
 386   if (dead->Opcode() == Op_Opaque4) {
 387     remove_skeleton_predicate_opaq(dead);
 388   }
 389   if (dead->for_post_loop_opts_igvn()) {
 390     remove_from_post_loop_opts_igvn(dead);
 391   }
 392   if (dead->is_Call()) {
 393     remove_useless_late_inlines(                &_late_inlines, dead);
 394     remove_useless_late_inlines(         &_string_late_inlines, dead);
 395     remove_useless_late_inlines(         &_boxing_late_inlines, dead);
 396     remove_useless_late_inlines(&_vector_reboxing_late_inlines, dead);
 397   }
 398   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 399   bs->unregister_potential_barrier_node(dead);
 400 }
 401 
 402 // Disconnect all useless nodes by disconnecting those at the boundary.
 403 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 404   uint next = 0;
 405   while (next < useful.size()) {
 406     Node *n = useful.at(next++);
 407     if (n->is_SafePoint()) {
 408       // We're done with a parsing phase. Replaced nodes are not valid
 409       // beyond that point.
 410       n->as_SafePoint()->delete_replaced_nodes();
 411     }
 412     // Use raw traversal of out edges since this code removes out edges
 413     int max = n->outcnt();
 414     for (int j = 0; j < max; ++j) {
 415       Node* child = n->raw_out(j);
 416       if (!useful.member(child)) {
 417         assert(!child->is_top() || child != top(),
 418                "If top is cached in Compile object it is in useful list");
 419         // Only need to remove this out-edge to the useless node
 420         n->raw_del_out(j);
 421         --j;
 422         --max;
 423       }
 424     }
 425     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 426       record_for_igvn(n->unique_out());
 427     }
 428   }
 429 
 430   remove_useless_nodes(_macro_nodes,        useful); // remove useless macro nodes
 431   remove_useless_nodes(_predicate_opaqs,    useful); // remove useless predicate opaque nodes
 432   remove_useless_nodes(_skeleton_predicate_opaqs, useful);
 433   remove_useless_nodes(_expensive_nodes,    useful); // remove useless expensive nodes
 434   remove_useless_nodes(_for_post_loop_igvn, useful); // remove useless node recorded for post loop opts IGVN pass
 435   remove_useless_coarsened_locks(useful);            // remove useless coarsened locks nodes
 436 
 437   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 438   bs->eliminate_useless_gc_barriers(useful, this);
 439   // clean up the late inline lists
 440   remove_useless_late_inlines(                &_late_inlines, useful);
 441   remove_useless_late_inlines(         &_string_late_inlines, useful);
 442   remove_useless_late_inlines(         &_boxing_late_inlines, useful);
 443   remove_useless_late_inlines(&_vector_reboxing_late_inlines, useful);
 444   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 445 }
 446 
 447 // ============================================================================
 448 //------------------------------CompileWrapper---------------------------------
 449 class CompileWrapper : public StackObj {
 450   Compile *const _compile;
 451  public:
 452   CompileWrapper(Compile* compile);
 453 
 454   ~CompileWrapper();
 455 };
 456 
 457 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 458   // the Compile* pointer is stored in the current ciEnv:
 459   ciEnv* env = compile->env();
 460   assert(env == ciEnv::current(), "must already be a ciEnv active");
 461   assert(env->compiler_data() == NULL, "compile already active?");
 462   env->set_compiler_data(compile);
 463   assert(compile == Compile::current(), "sanity");
 464 
 465   compile->set_type_dict(NULL);
 466   compile->set_clone_map(new Dict(cmpkey, hashkey, _compile->comp_arena()));
 467   compile->clone_map().set_clone_idx(0);
 468   compile->set_type_last_size(0);
 469   compile->set_last_tf(NULL, NULL);
 470   compile->set_indexSet_arena(NULL);
 471   compile->set_indexSet_free_block_list(NULL);
 472   compile->init_type_arena();
 473   Type::Initialize(compile);
 474   _compile->begin_method();
 475   _compile->clone_map().set_debug(_compile->has_method() && _compile->directive()->CloneMapDebugOption);
 476 }
 477 CompileWrapper::~CompileWrapper() {
 478   // simulate crash during compilation
 479   assert(CICrashAt < 0 || _compile->compile_id() != CICrashAt, "just as planned");
 480 
 481   _compile->end_method();
 482   _compile->env()->set_compiler_data(NULL);
 483 }
 484 
 485 
 486 //----------------------------print_compile_messages---------------------------
 487 void Compile::print_compile_messages() {
 488 #ifndef PRODUCT
 489   // Check if recompiling
 490   if (_subsume_loads == false && PrintOpto) {
 491     // Recompiling without allowing machine instructions to subsume loads
 492     tty->print_cr("*********************************************************");
 493     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 494     tty->print_cr("*********************************************************");
 495   }
 496   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 497     // Recompiling without escape analysis
 498     tty->print_cr("*********************************************************");
 499     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 500     tty->print_cr("*********************************************************");
 501   }
 502   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 503     // Recompiling without boxing elimination
 504     tty->print_cr("*********************************************************");
 505     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 506     tty->print_cr("*********************************************************");
 507   }
 508   if ((_do_locks_coarsening != EliminateLocks) && PrintOpto) {
 509     // Recompiling without locks coarsening
 510     tty->print_cr("*********************************************************");
 511     tty->print_cr("** Bailout: Recompile without locks coarsening         **");
 512     tty->print_cr("*********************************************************");
 513   }
 514   if (env()->break_at_compile()) {
 515     // Open the debugger when compiling this method.
 516     tty->print("### Breaking when compiling: ");
 517     method()->print_short_name();
 518     tty->cr();
 519     BREAKPOINT;
 520   }
 521 
 522   if( PrintOpto ) {
 523     if (is_osr_compilation()) {
 524       tty->print("[OSR]%3d", _compile_id);
 525     } else {
 526       tty->print("%3d", _compile_id);
 527     }
 528   }
 529 #endif
 530 }
 531 
 532 // ============================================================================
 533 //------------------------------Compile standard-------------------------------
 534 debug_only( int Compile::_debug_idx = 100000; )
 535 
 536 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 537 // the continuation bci for on stack replacement.
 538 
 539 
 540 Compile::Compile( ciEnv* ci_env, ciMethod* target, int osr_bci,
 541                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing,
 542                   bool do_locks_coarsening, bool install_code, DirectiveSet* directive)
 543                 : Phase(Compiler),
 544                   _compile_id(ci_env->compile_id()),
 545                   _subsume_loads(subsume_loads),
 546                   _do_escape_analysis(do_escape_analysis),
 547                   _install_code(install_code),
 548                   _eliminate_boxing(eliminate_boxing),
 549                   _do_locks_coarsening(do_locks_coarsening),
 550                   _method(target),
 551                   _entry_bci(osr_bci),
 552                   _stub_function(NULL),
 553                   _stub_name(NULL),
 554                   _stub_entry_point(NULL),
 555                   _max_node_limit(MaxNodeLimit),
 556                   _post_loop_opts_phase(false),
 557                   _inlining_progress(false),
 558                   _inlining_incrementally(false),
 559                   _do_cleanup(false),
 560                   _has_reserved_stack_access(target->has_reserved_stack_access()),
 561 #ifndef PRODUCT
 562                   _igv_idx(0),
 563                   _trace_opto_output(directive->TraceOptoOutputOption),
 564                   _print_ideal(directive->PrintIdealOption),
 565 #endif
 566                   _has_method_handle_invokes(false),
 567                   _clinit_barrier_on_entry(false),
 568                   _stress_seed(0),
 569                   _comp_arena(mtCompiler),
 570                   _barrier_set_state(BarrierSet::barrier_set()->barrier_set_c2()->create_barrier_state(comp_arena())),
 571                   _env(ci_env),
 572                   _directive(directive),
 573                   _log(ci_env->log()),
 574                   _failure_reason(NULL),
 575                   _intrinsics        (comp_arena(), 0, 0, NULL),
 576                   _macro_nodes       (comp_arena(), 8, 0, NULL),
 577                   _predicate_opaqs   (comp_arena(), 8, 0, NULL),
 578                   _skeleton_predicate_opaqs (comp_arena(), 8, 0, NULL),
 579                   _expensive_nodes   (comp_arena(), 8, 0, NULL),
 580                   _for_post_loop_igvn(comp_arena(), 8, 0, NULL),
 581                   _coarsened_locks   (comp_arena(), 8, 0, NULL),
 582                   _congraph(NULL),
 583                   NOT_PRODUCT(_printer(NULL) COMMA)
 584                   _dead_node_list(comp_arena()),
 585                   _dead_node_count(0),
 586                   _node_arena(mtCompiler),
 587                   _old_arena(mtCompiler),
 588                   _mach_constant_base_node(NULL),
 589                   _Compile_types(mtCompiler),
 590                   _initial_gvn(NULL),
 591                   _for_igvn(NULL),
 592                   _late_inlines(comp_arena(), 2, 0, NULL),
 593                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 594                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 595                   _vector_reboxing_late_inlines(comp_arena(), 2, 0, NULL),
 596                   _late_inlines_pos(0),
 597                   _number_of_mh_late_inlines(0),
 598                   _native_invokers(comp_arena(), 1, 0, NULL),
 599                   _print_inlining_stream(NULL),
 600                   _print_inlining_list(NULL),
 601                   _print_inlining_idx(0),
 602                   _print_inlining_output(NULL),
 603                   _replay_inline_data(NULL),
 604                   _java_calls(0),
 605                   _inner_loops(0),
 606                   _interpreter_frame_size(0)
 607 #ifndef PRODUCT
 608                   , _in_dump_cnt(0)
 609 #endif
 610 {
 611   C = this;
 612   CompileWrapper cw(this);
 613 
 614   if (CITimeVerbose) {
 615     tty->print(" ");
 616     target->holder()->name()->print();
 617     tty->print(".");
 618     target->print_short_name();
 619     tty->print("  ");
 620   }
 621   TraceTime t1("Total compilation time", &_t_totalCompilation, CITime, CITimeVerbose);
 622   TraceTime t2(NULL, &_t_methodCompilation, CITime, false);
 623 
 624 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
 625   bool print_opto_assembly = directive->PrintOptoAssemblyOption;
 626   // We can always print a disassembly, either abstract (hex dump) or
 627   // with the help of a suitable hsdis library. Thus, we should not
 628   // couple print_assembly and print_opto_assembly controls.
 629   // But: always print opto and regular assembly on compile command 'print'.
 630   bool print_assembly = directive->PrintAssemblyOption;
 631   set_print_assembly(print_opto_assembly || print_assembly);
 632 #else
 633   set_print_assembly(false); // must initialize.
 634 #endif
 635 
 636 #ifndef PRODUCT
 637   set_parsed_irreducible_loop(false);
 638 
 639   if (directive->ReplayInlineOption) {
 640     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 641   }
 642 #endif
 643   set_print_inlining(directive->PrintInliningOption || PrintOptoInlining);
 644   set_print_intrinsics(directive->PrintIntrinsicsOption);
 645   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 646 
 647   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 648     // Make sure the method being compiled gets its own MDO,
 649     // so we can at least track the decompile_count().
 650     // Need MDO to record RTM code generation state.
 651     method()->ensure_method_data();
 652   }
 653 
 654   Init(::AliasLevel);
 655 
 656 
 657   print_compile_messages();
 658 
 659   _ilt = InlineTree::build_inline_tree_root();
 660 
 661   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 662   assert(num_alias_types() >= AliasIdxRaw, "");
 663 
 664 #define MINIMUM_NODE_HASH  1023
 665   // Node list that Iterative GVN will start with
 666   Unique_Node_List for_igvn(comp_arena());
 667   set_for_igvn(&for_igvn);
 668 
 669   // GVN that will be run immediately on new nodes
 670   uint estimated_size = method()->code_size()*4+64;
 671   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 672   PhaseGVN gvn(node_arena(), estimated_size);
 673   set_initial_gvn(&gvn);
 674 
 675   print_inlining_init();
 676   { // Scope for timing the parser
 677     TracePhase tp("parse", &timers[_t_parser]);
 678 
 679     // Put top into the hash table ASAP.
 680     initial_gvn()->transform_no_reclaim(top());
 681 
 682     // Set up tf(), start(), and find a CallGenerator.
 683     CallGenerator* cg = NULL;
 684     if (is_osr_compilation()) {
 685       const TypeTuple *domain = StartOSRNode::osr_domain();
 686       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 687       init_tf(TypeFunc::make(domain, range));
 688       StartNode* s = new StartOSRNode(root(), domain);
 689       initial_gvn()->set_type_bottom(s);
 690       init_start(s);
 691       cg = CallGenerator::for_osr(method(), entry_bci());
 692     } else {
 693       // Normal case.
 694       init_tf(TypeFunc::make(method()));
 695       StartNode* s = new StartNode(root(), tf()->domain());
 696       initial_gvn()->set_type_bottom(s);
 697       init_start(s);
 698       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get) {
 699         // With java.lang.ref.reference.get() we must go through the
 700         // intrinsic - even when get() is the root
 701         // method of the compile - so that, if necessary, the value in
 702         // the referent field of the reference object gets recorded by
 703         // the pre-barrier code.
 704         cg = find_intrinsic(method(), false);
 705       }
 706       if (cg == NULL) {
 707         float past_uses = method()->interpreter_invocation_count();
 708         float expected_uses = past_uses;
 709         cg = CallGenerator::for_inline(method(), expected_uses);
 710       }
 711     }
 712     if (failing())  return;
 713     if (cg == NULL) {
 714       record_method_not_compilable("cannot parse method");
 715       return;
 716     }
 717     JVMState* jvms = build_start_state(start(), tf());
 718     if ((jvms = cg->generate(jvms)) == NULL) {
 719       if (!failure_reason_is(C2Compiler::retry_class_loading_during_parsing())) {
 720         record_method_not_compilable("method parse failed");
 721       }
 722       return;
 723     }
 724     GraphKit kit(jvms);
 725 
 726     if (!kit.stopped()) {
 727       // Accept return values, and transfer control we know not where.
 728       // This is done by a special, unique ReturnNode bound to root.
 729       return_values(kit.jvms());
 730     }
 731 
 732     if (kit.has_exceptions()) {
 733       // Any exceptions that escape from this call must be rethrown
 734       // to whatever caller is dynamically above us on the stack.
 735       // This is done by a special, unique RethrowNode bound to root.
 736       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 737     }
 738 
 739     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 740 
 741     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 742       inline_string_calls(true);
 743     }
 744 
 745     if (failing())  return;
 746 
 747     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 748 
 749     // Remove clutter produced by parsing.
 750     if (!failing()) {
 751       ResourceMark rm;
 752       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 753     }
 754   }
 755 
 756   // Note:  Large methods are capped off in do_one_bytecode().
 757   if (failing())  return;
 758 
 759   // After parsing, node notes are no longer automagic.
 760   // They must be propagated by register_new_node_with_optimizer(),
 761   // clone(), or the like.
 762   set_default_node_notes(NULL);
 763 
 764 #ifndef PRODUCT
 765   if (should_print(1)) {
 766     _printer->print_inlining();
 767   }
 768 #endif
 769 
 770   if (failing())  return;
 771   NOT_PRODUCT( verify_graph_edges(); )
 772 
 773   // If any phase is randomized for stress testing, seed random number
 774   // generation and log the seed for repeatability.
 775   if (StressLCM || StressGCM || StressIGVN || StressCCP) {
 776     if (FLAG_IS_DEFAULT(StressSeed) || (FLAG_IS_ERGO(StressSeed) && RepeatCompilation)) {
 777       _stress_seed = static_cast<uint>(Ticks::now().nanoseconds());
 778       FLAG_SET_ERGO(StressSeed, _stress_seed);
 779     } else {
 780       _stress_seed = StressSeed;
 781     }
 782     if (_log != NULL) {
 783       _log->elem("stress_test seed='%u'", _stress_seed);
 784     }
 785   }
 786 
 787   // Now optimize
 788   Optimize();
 789   if (failing())  return;
 790   NOT_PRODUCT( verify_graph_edges(); )
 791 
 792 #ifndef PRODUCT
 793   if (print_ideal()) {
 794     ttyLocker ttyl;  // keep the following output all in one block
 795     // This output goes directly to the tty, not the compiler log.
 796     // To enable tools to match it up with the compilation activity,
 797     // be sure to tag this tty output with the compile ID.
 798     if (xtty != NULL) {
 799       xtty->head("ideal compile_id='%d'%s", compile_id(),
 800                  is_osr_compilation()    ? " compile_kind='osr'" :
 801                  "");
 802     }
 803     root()->dump(9999);
 804     if (xtty != NULL) {
 805       xtty->tail("ideal");
 806     }
 807   }
 808 #endif
 809 
 810 #ifdef ASSERT
 811   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 812   bs->verify_gc_barriers(this, BarrierSetC2::BeforeCodeGen);
 813 #endif
 814 
 815   // Dump compilation data to replay it.
 816   if (directive->DumpReplayOption) {
 817     env()->dump_replay_data(_compile_id);
 818   }
 819   if (directive->DumpInlineOption && (ilt() != NULL)) {
 820     env()->dump_inline_data(_compile_id);
 821   }
 822 
 823   // Now that we know the size of all the monitors we can add a fixed slot
 824   // for the original deopt pc.
 825   int next_slot = fixed_slots() + (sizeof(address) / VMRegImpl::stack_slot_size);
 826   set_fixed_slots(next_slot);
 827 
 828   // Compute when to use implicit null checks. Used by matching trap based
 829   // nodes and NullCheck optimization.
 830   set_allowed_deopt_reasons();
 831 
 832   // Now generate code
 833   Code_Gen();
 834 }
 835 
 836 //------------------------------Compile----------------------------------------
 837 // Compile a runtime stub
 838 Compile::Compile( ciEnv* ci_env,
 839                   TypeFunc_generator generator,
 840                   address stub_function,
 841                   const char *stub_name,
 842                   int is_fancy_jump,
 843                   bool pass_tls,
 844                   bool return_pc,
 845                   DirectiveSet* directive)
 846   : Phase(Compiler),
 847     _compile_id(0),
 848     _subsume_loads(true),
 849     _do_escape_analysis(false),
 850     _install_code(true),
 851     _eliminate_boxing(false),
 852     _do_locks_coarsening(false),
 853     _method(NULL),
 854     _entry_bci(InvocationEntryBci),
 855     _stub_function(stub_function),
 856     _stub_name(stub_name),
 857     _stub_entry_point(NULL),
 858     _max_node_limit(MaxNodeLimit),
 859     _post_loop_opts_phase(false),
 860     _inlining_progress(false),
 861     _inlining_incrementally(false),
 862     _has_reserved_stack_access(false),
 863 #ifndef PRODUCT
 864     _igv_idx(0),
 865     _trace_opto_output(directive->TraceOptoOutputOption),
 866     _print_ideal(directive->PrintIdealOption),
 867 #endif
 868     _has_method_handle_invokes(false),
 869     _clinit_barrier_on_entry(false),
 870     _stress_seed(0),
 871     _comp_arena(mtCompiler),
 872     _barrier_set_state(BarrierSet::barrier_set()->barrier_set_c2()->create_barrier_state(comp_arena())),
 873     _env(ci_env),
 874     _directive(directive),
 875     _log(ci_env->log()),
 876     _failure_reason(NULL),
 877     _congraph(NULL),
 878     NOT_PRODUCT(_printer(NULL) COMMA)
 879     _dead_node_list(comp_arena()),
 880     _dead_node_count(0),
 881     _node_arena(mtCompiler),
 882     _old_arena(mtCompiler),
 883     _mach_constant_base_node(NULL),
 884     _Compile_types(mtCompiler),
 885     _initial_gvn(NULL),
 886     _for_igvn(NULL),
 887     _number_of_mh_late_inlines(0),
 888     _native_invokers(),
 889     _print_inlining_stream(NULL),
 890     _print_inlining_list(NULL),
 891     _print_inlining_idx(0),
 892     _print_inlining_output(NULL),
 893     _replay_inline_data(NULL),
 894     _java_calls(0),
 895     _inner_loops(0),
 896     _interpreter_frame_size(0),
 897 #ifndef PRODUCT
 898     _in_dump_cnt(0),
 899 #endif
 900     _allowed_reasons(0) {
 901   C = this;
 902 
 903   TraceTime t1(NULL, &_t_totalCompilation, CITime, false);
 904   TraceTime t2(NULL, &_t_stubCompilation, CITime, false);
 905 
 906 #ifndef PRODUCT
 907   set_print_assembly(PrintFrameConverterAssembly);
 908   set_parsed_irreducible_loop(false);
 909 #else
 910   set_print_assembly(false); // Must initialize.
 911 #endif
 912   set_has_irreducible_loop(false); // no loops
 913 
 914   CompileWrapper cw(this);
 915   Init(/*AliasLevel=*/ 0);
 916   init_tf((*generator)());
 917 
 918   {
 919     // The following is a dummy for the sake of GraphKit::gen_stub
 920     Unique_Node_List for_igvn(comp_arena());
 921     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
 922     PhaseGVN gvn(Thread::current()->resource_area(),255);
 923     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
 924     gvn.transform_no_reclaim(top());
 925 
 926     GraphKit kit;
 927     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
 928   }
 929 
 930   NOT_PRODUCT( verify_graph_edges(); )
 931 
 932   Code_Gen();
 933 }
 934 
 935 //------------------------------Init-------------------------------------------
 936 // Prepare for a single compilation
 937 void Compile::Init(int aliaslevel) {
 938   _unique  = 0;
 939   _regalloc = NULL;
 940 
 941   _tf      = NULL;  // filled in later
 942   _top     = NULL;  // cached later
 943   _matcher = NULL;  // filled in later
 944   _cfg     = NULL;  // filled in later
 945 
 946   IA32_ONLY( set_24_bit_selection_and_mode(true, false); )
 947 
 948   _node_note_array = NULL;
 949   _default_node_notes = NULL;
 950   DEBUG_ONLY( _modified_nodes = NULL; ) // Used in Optimize()
 951 
 952   _immutable_memory = NULL; // filled in at first inquiry
 953 
 954   // Globally visible Nodes
 955   // First set TOP to NULL to give safe behavior during creation of RootNode
 956   set_cached_top_node(NULL);
 957   set_root(new RootNode());
 958   // Now that you have a Root to point to, create the real TOP
 959   set_cached_top_node( new ConNode(Type::TOP) );
 960   set_recent_alloc(NULL, NULL);
 961 
 962   // Create Debug Information Recorder to record scopes, oopmaps, etc.
 963   env()->set_oop_recorder(new OopRecorder(env()->arena()));
 964   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
 965   env()->set_dependencies(new Dependencies(env()));
 966 
 967   _fixed_slots = 0;
 968   set_has_split_ifs(false);
 969   set_has_loops(false); // first approximation
 970   set_has_stringbuilder(false);
 971   set_has_boxed_value(false);
 972   _trap_can_recompile = false;  // no traps emitted yet
 973   _major_progress = true; // start out assuming good things will happen
 974   set_has_unsafe_access(false);
 975   set_max_vector_size(0);
 976   set_clear_upper_avx(false);  //false as default for clear upper bits of ymm registers
 977   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
 978   set_decompile_count(0);
 979 
 980   set_do_freq_based_layout(_directive->BlockLayoutByFrequencyOption);
 981   _loop_opts_cnt = LoopOptsCount;
 982   set_do_inlining(Inline);
 983   set_max_inline_size(MaxInlineSize);
 984   set_freq_inline_size(FreqInlineSize);
 985   set_do_scheduling(OptoScheduling);
 986 
 987   set_do_vector_loop(false);
 988 
 989   if (AllowVectorizeOnDemand) {
 990     if (has_method() && (_directive->VectorizeOption || _directive->VectorizeDebugOption)) {
 991       set_do_vector_loop(true);
 992       NOT_PRODUCT(if (do_vector_loop() && Verbose) {tty->print("Compile::Init: do vectorized loops (SIMD like) for method %s\n",  method()->name()->as_quoted_ascii());})
 993     } else if (has_method() && method()->name() != 0 &&
 994                method()->intrinsic_id() == vmIntrinsics::_forEachRemaining) {
 995       set_do_vector_loop(true);
 996     }
 997   }
 998   set_use_cmove(UseCMoveUnconditionally /* || do_vector_loop()*/); //TODO: consider do_vector_loop() mandate use_cmove unconditionally
 999   NOT_PRODUCT(if (use_cmove() && Verbose && has_method()) {tty->print("Compile::Init: use CMove without profitability tests for method %s\n",  method()->name()->as_quoted_ascii());})
1000 
1001   set_age_code(has_method() && method()->profile_aging());
1002   set_rtm_state(NoRTM); // No RTM lock eliding by default
1003   _max_node_limit = _directive->MaxNodeLimitOption;
1004 
1005 #if INCLUDE_RTM_OPT
1006   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1007     int rtm_state = method()->method_data()->rtm_state();
1008     if (method_has_option(CompileCommand::NoRTMLockEliding) || ((rtm_state & NoRTM) != 0)) {
1009       // Don't generate RTM lock eliding code.
1010       set_rtm_state(NoRTM);
1011     } else if (method_has_option(CompileCommand::UseRTMLockEliding) || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1012       // Generate RTM lock eliding code without abort ratio calculation code.
1013       set_rtm_state(UseRTM);
1014     } else if (UseRTMDeopt) {
1015       // Generate RTM lock eliding code and include abort ratio calculation
1016       // code if UseRTMDeopt is on.
1017       set_rtm_state(ProfileRTM);
1018     }
1019   }
1020 #endif
1021   if (VM_Version::supports_fast_class_init_checks() && has_method() && !is_osr_compilation() && method()->needs_clinit_barrier()) {
1022     set_clinit_barrier_on_entry(true);
1023   }
1024   if (debug_info()->recording_non_safepoints()) {
1025     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1026                         (comp_arena(), 8, 0, NULL));
1027     set_default_node_notes(Node_Notes::make(this));
1028   }
1029 
1030   // // -- Initialize types before each compile --
1031   // // Update cached type information
1032   // if( _method && _method->constants() )
1033   //   Type::update_loaded_types(_method, _method->constants());
1034 
1035   // Init alias_type map.
1036   if (!_do_escape_analysis && aliaslevel == 3)
1037     aliaslevel = 2;  // No unique types without escape analysis
1038   _AliasLevel = aliaslevel;
1039   const int grow_ats = 16;
1040   _max_alias_types = grow_ats;
1041   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1042   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1043   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1044   {
1045     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1046   }
1047   // Initialize the first few types.
1048   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1049   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1050   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1051   _num_alias_types = AliasIdxRaw+1;
1052   // Zero out the alias type cache.
1053   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1054   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1055   probe_alias_cache(NULL)->_index = AliasIdxTop;
1056 
1057 #ifdef ASSERT
1058   _type_verify_symmetry = true;
1059   _phase_optimize_finished = false;
1060   _exception_backedge = false;
1061 #endif
1062 }
1063 
1064 //---------------------------init_start----------------------------------------
1065 // Install the StartNode on this compile object.
1066 void Compile::init_start(StartNode* s) {
1067   if (failing())
1068     return; // already failing
1069   assert(s == start(), "");
1070 }
1071 
1072 /**
1073  * Return the 'StartNode'. We must not have a pending failure, since the ideal graph
1074  * can be in an inconsistent state, i.e., we can get segmentation faults when traversing
1075  * the ideal graph.
1076  */
1077 StartNode* Compile::start() const {
1078   assert (!failing(), "Must not have pending failure. Reason is: %s", failure_reason());
1079   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1080     Node* start = root()->fast_out(i);
1081     if (start->is_Start()) {
1082       return start->as_Start();
1083     }
1084   }
1085   fatal("Did not find Start node!");
1086   return NULL;
1087 }
1088 
1089 //-------------------------------immutable_memory-------------------------------------
1090 // Access immutable memory
1091 Node* Compile::immutable_memory() {
1092   if (_immutable_memory != NULL) {
1093     return _immutable_memory;
1094   }
1095   StartNode* s = start();
1096   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1097     Node *p = s->fast_out(i);
1098     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1099       _immutable_memory = p;
1100       return _immutable_memory;
1101     }
1102   }
1103   ShouldNotReachHere();
1104   return NULL;
1105 }
1106 
1107 //----------------------set_cached_top_node------------------------------------
1108 // Install the cached top node, and make sure Node::is_top works correctly.
1109 void Compile::set_cached_top_node(Node* tn) {
1110   if (tn != NULL)  verify_top(tn);
1111   Node* old_top = _top;
1112   _top = tn;
1113   // Calling Node::setup_is_top allows the nodes the chance to adjust
1114   // their _out arrays.
1115   if (_top != NULL)     _top->setup_is_top();
1116   if (old_top != NULL)  old_top->setup_is_top();
1117   assert(_top == NULL || top()->is_top(), "");
1118 }
1119 
1120 #ifdef ASSERT
1121 uint Compile::count_live_nodes_by_graph_walk() {
1122   Unique_Node_List useful(comp_arena());
1123   // Get useful node list by walking the graph.
1124   identify_useful_nodes(useful);
1125   return useful.size();
1126 }
1127 
1128 void Compile::print_missing_nodes() {
1129 
1130   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1131   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1132     return;
1133   }
1134 
1135   // This is an expensive function. It is executed only when the user
1136   // specifies VerifyIdealNodeCount option or otherwise knows the
1137   // additional work that needs to be done to identify reachable nodes
1138   // by walking the flow graph and find the missing ones using
1139   // _dead_node_list.
1140 
1141   Unique_Node_List useful(comp_arena());
1142   // Get useful node list by walking the graph.
1143   identify_useful_nodes(useful);
1144 
1145   uint l_nodes = C->live_nodes();
1146   uint l_nodes_by_walk = useful.size();
1147 
1148   if (l_nodes != l_nodes_by_walk) {
1149     if (_log != NULL) {
1150       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1151       _log->stamp();
1152       _log->end_head();
1153     }
1154     VectorSet& useful_member_set = useful.member_set();
1155     int last_idx = l_nodes_by_walk;
1156     for (int i = 0; i < last_idx; i++) {
1157       if (useful_member_set.test(i)) {
1158         if (_dead_node_list.test(i)) {
1159           if (_log != NULL) {
1160             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1161           }
1162           if (PrintIdealNodeCount) {
1163             // Print the log message to tty
1164               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1165               useful.at(i)->dump();
1166           }
1167         }
1168       }
1169       else if (! _dead_node_list.test(i)) {
1170         if (_log != NULL) {
1171           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1172         }
1173         if (PrintIdealNodeCount) {
1174           // Print the log message to tty
1175           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1176         }
1177       }
1178     }
1179     if (_log != NULL) {
1180       _log->tail("mismatched_nodes");
1181     }
1182   }
1183 }
1184 void Compile::record_modified_node(Node* n) {
1185   if (_modified_nodes != NULL && !_inlining_incrementally && !n->is_Con()) {
1186     _modified_nodes->push(n);
1187   }
1188 }
1189 
1190 void Compile::remove_modified_node(Node* n) {
1191   if (_modified_nodes != NULL) {
1192     _modified_nodes->remove(n);
1193   }
1194 }
1195 #endif
1196 
1197 #ifndef PRODUCT
1198 void Compile::verify_top(Node* tn) const {
1199   if (tn != NULL) {
1200     assert(tn->is_Con(), "top node must be a constant");
1201     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1202     assert(tn->in(0) != NULL, "must have live top node");
1203   }
1204 }
1205 #endif
1206 
1207 
1208 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1209 
1210 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1211   guarantee(arr != NULL, "");
1212   int num_blocks = arr->length();
1213   if (grow_by < num_blocks)  grow_by = num_blocks;
1214   int num_notes = grow_by * _node_notes_block_size;
1215   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1216   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1217   while (num_notes > 0) {
1218     arr->append(notes);
1219     notes     += _node_notes_block_size;
1220     num_notes -= _node_notes_block_size;
1221   }
1222   assert(num_notes == 0, "exact multiple, please");
1223 }
1224 
1225 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1226   if (source == NULL || dest == NULL)  return false;
1227 
1228   if (dest->is_Con())
1229     return false;               // Do not push debug info onto constants.
1230 
1231 #ifdef ASSERT
1232   // Leave a bread crumb trail pointing to the original node:
1233   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1234     dest->set_debug_orig(source);
1235   }
1236 #endif
1237 
1238   if (node_note_array() == NULL)
1239     return false;               // Not collecting any notes now.
1240 
1241   // This is a copy onto a pre-existing node, which may already have notes.
1242   // If both nodes have notes, do not overwrite any pre-existing notes.
1243   Node_Notes* source_notes = node_notes_at(source->_idx);
1244   if (source_notes == NULL || source_notes->is_clear())  return false;
1245   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1246   if (dest_notes == NULL || dest_notes->is_clear()) {
1247     return set_node_notes_at(dest->_idx, source_notes);
1248   }
1249 
1250   Node_Notes merged_notes = (*source_notes);
1251   // The order of operations here ensures that dest notes will win...
1252   merged_notes.update_from(dest_notes);
1253   return set_node_notes_at(dest->_idx, &merged_notes);
1254 }
1255 
1256 
1257 //--------------------------allow_range_check_smearing-------------------------
1258 // Gating condition for coalescing similar range checks.
1259 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1260 // single covering check that is at least as strong as any of them.
1261 // If the optimization succeeds, the simplified (strengthened) range check
1262 // will always succeed.  If it fails, we will deopt, and then give up
1263 // on the optimization.
1264 bool Compile::allow_range_check_smearing() const {
1265   // If this method has already thrown a range-check,
1266   // assume it was because we already tried range smearing
1267   // and it failed.
1268   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1269   return !already_trapped;
1270 }
1271 
1272 
1273 //------------------------------flatten_alias_type-----------------------------
1274 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1275   int offset = tj->offset();
1276   TypePtr::PTR ptr = tj->ptr();
1277 
1278   // Known instance (scalarizable allocation) alias only with itself.
1279   bool is_known_inst = tj->isa_oopptr() != NULL &&
1280                        tj->is_oopptr()->is_known_instance();
1281 
1282   // Process weird unsafe references.
1283   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1284     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1285     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1286     tj = TypeOopPtr::BOTTOM;
1287     ptr = tj->ptr();
1288     offset = tj->offset();
1289   }
1290 
1291   // Array pointers need some flattening
1292   const TypeAryPtr *ta = tj->isa_aryptr();
1293   if (ta && ta->is_stable()) {
1294     // Erase stability property for alias analysis.
1295     tj = ta = ta->cast_to_stable(false);
1296   }
1297   if( ta && is_known_inst ) {
1298     if ( offset != Type::OffsetBot &&
1299          offset > arrayOopDesc::length_offset_in_bytes() ) {
1300       offset = Type::OffsetBot; // Flatten constant access into array body only
1301       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1302     }
1303   } else if( ta && _AliasLevel >= 2 ) {
1304     // For arrays indexed by constant indices, we flatten the alias
1305     // space to include all of the array body.  Only the header, klass
1306     // and array length can be accessed un-aliased.
1307     if( offset != Type::OffsetBot ) {
1308       if( ta->const_oop() ) { // MethodData* or Method*
1309         offset = Type::OffsetBot;   // Flatten constant access into array body
1310         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1311       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1312         // range is OK as-is.
1313         tj = ta = TypeAryPtr::RANGE;
1314       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1315         tj = TypeInstPtr::KLASS; // all klass loads look alike
1316         ta = TypeAryPtr::RANGE; // generic ignored junk
1317         ptr = TypePtr::BotPTR;
1318       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1319         tj = TypeInstPtr::MARK;
1320         ta = TypeAryPtr::RANGE; // generic ignored junk
1321         ptr = TypePtr::BotPTR;
1322       } else {                  // Random constant offset into array body
1323         offset = Type::OffsetBot;   // Flatten constant access into array body
1324         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1325       }
1326     }
1327     // Arrays of fixed size alias with arrays of unknown size.
1328     if (ta->size() != TypeInt::POS) {
1329       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1330       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1331     }
1332     // Arrays of known objects become arrays of unknown objects.
1333     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1334       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1335       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1336     }
1337     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1338       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1339       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1340     }
1341     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1342     // cannot be distinguished by bytecode alone.
1343     if (ta->elem() == TypeInt::BOOL) {
1344       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1345       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1346       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1347     }
1348     // During the 2nd round of IterGVN, NotNull castings are removed.
1349     // Make sure the Bottom and NotNull variants alias the same.
1350     // Also, make sure exact and non-exact variants alias the same.
1351     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1352       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1353     }
1354   }
1355 
1356   // Oop pointers need some flattening
1357   const TypeInstPtr *to = tj->isa_instptr();
1358   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1359     ciInstanceKlass *k = to->klass()->as_instance_klass();
1360     if( ptr == TypePtr::Constant ) {
1361       if (to->klass() != ciEnv::current()->Class_klass() ||
1362           offset < k->layout_helper_size_in_bytes()) {
1363         // No constant oop pointers (such as Strings); they alias with
1364         // unknown strings.
1365         assert(!is_known_inst, "not scalarizable allocation");
1366         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1367       }
1368     } else if( is_known_inst ) {
1369       tj = to; // Keep NotNull and klass_is_exact for instance type
1370     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1371       // During the 2nd round of IterGVN, NotNull castings are removed.
1372       // Make sure the Bottom and NotNull variants alias the same.
1373       // Also, make sure exact and non-exact variants alias the same.
1374       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1375     }
1376     if (to->speculative() != NULL) {
1377       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1378     }
1379     // Canonicalize the holder of this field
1380     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1381       // First handle header references such as a LoadKlassNode, even if the
1382       // object's klass is unloaded at compile time (4965979).
1383       if (!is_known_inst) { // Do it only for non-instance types
1384         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1385       }
1386     } else if (offset < 0 || offset >= k->layout_helper_size_in_bytes()) {
1387       // Static fields are in the space above the normal instance
1388       // fields in the java.lang.Class instance.
1389       if (to->klass() != ciEnv::current()->Class_klass()) {
1390         to = NULL;
1391         tj = TypeOopPtr::BOTTOM;
1392         offset = tj->offset();
1393       }
1394     } else {
1395       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1396       assert(offset < canonical_holder->layout_helper_size_in_bytes(), "");
1397       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1398         if( is_known_inst ) {
1399           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1400         } else {
1401           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1402         }
1403       }
1404     }
1405   }
1406 
1407   // Klass pointers to object array klasses need some flattening
1408   const TypeKlassPtr *tk = tj->isa_klassptr();
1409   if( tk ) {
1410     // If we are referencing a field within a Klass, we need
1411     // to assume the worst case of an Object.  Both exact and
1412     // inexact types must flatten to the same alias class so
1413     // use NotNull as the PTR.
1414     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1415 
1416       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1417                                    TypeInstKlassPtr::OBJECT->klass(),
1418                                    offset);
1419     }
1420 
1421     ciKlass* klass = tk->klass();
1422     if( klass->is_obj_array_klass() ) {
1423       ciKlass* k = TypeAryPtr::OOPS->klass();
1424       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1425         k = TypeInstPtr::BOTTOM->klass();
1426       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1427     }
1428 
1429     // Check for precise loads from the primary supertype array and force them
1430     // to the supertype cache alias index.  Check for generic array loads from
1431     // the primary supertype array and also force them to the supertype cache
1432     // alias index.  Since the same load can reach both, we need to merge
1433     // these 2 disparate memories into the same alias class.  Since the
1434     // primary supertype array is read-only, there's no chance of confusion
1435     // where we bypass an array load and an array store.
1436     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1437     if (offset == Type::OffsetBot ||
1438         (offset >= primary_supers_offset &&
1439          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1440         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1441       offset = in_bytes(Klass::secondary_super_cache_offset());
1442       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1443     }
1444   }
1445 
1446   // Flatten all Raw pointers together.
1447   if (tj->base() == Type::RawPtr)
1448     tj = TypeRawPtr::BOTTOM;
1449 
1450   if (tj->base() == Type::AnyPtr)
1451     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1452 
1453   // Flatten all to bottom for now
1454   switch( _AliasLevel ) {
1455   case 0:
1456     tj = TypePtr::BOTTOM;
1457     break;
1458   case 1:                       // Flatten to: oop, static, field or array
1459     switch (tj->base()) {
1460     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1461     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1462     case Type::AryPtr:   // do not distinguish arrays at all
1463     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1464     case Type::KlassPtr:
1465     case Type::AryKlassPtr:
1466     case Type::InstKlassPtr: tj = TypeInstKlassPtr::OBJECT; break;
1467     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1468     default: ShouldNotReachHere();
1469     }
1470     break;
1471   case 2:                       // No collapsing at level 2; keep all splits
1472   case 3:                       // No collapsing at level 3; keep all splits
1473     break;
1474   default:
1475     Unimplemented();
1476   }
1477 
1478   offset = tj->offset();
1479   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1480 
1481   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1482           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1483           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1484           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1485           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1486           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1487           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr),
1488           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1489   assert( tj->ptr() != TypePtr::TopPTR &&
1490           tj->ptr() != TypePtr::AnyNull &&
1491           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1492 //    assert( tj->ptr() != TypePtr::Constant ||
1493 //            tj->base() == Type::RawPtr ||
1494 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1495 
1496   return tj;
1497 }
1498 
1499 void Compile::AliasType::Init(int i, const TypePtr* at) {
1500   assert(AliasIdxTop <= i && i < Compile::current()->_max_alias_types, "Invalid alias index");
1501   _index = i;
1502   _adr_type = at;
1503   _field = NULL;
1504   _element = NULL;
1505   _is_rewritable = true; // default
1506   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1507   if (atoop != NULL && atoop->is_known_instance()) {
1508     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1509     _general_index = Compile::current()->get_alias_index(gt);
1510   } else {
1511     _general_index = 0;
1512   }
1513 }
1514 
1515 BasicType Compile::AliasType::basic_type() const {
1516   if (element() != NULL) {
1517     const Type* element = adr_type()->is_aryptr()->elem();
1518     return element->isa_narrowoop() ? T_OBJECT : element->array_element_basic_type();
1519   } if (field() != NULL) {
1520     return field()->layout_type();
1521   } else {
1522     return T_ILLEGAL; // unknown
1523   }
1524 }
1525 
1526 //---------------------------------print_on------------------------------------
1527 #ifndef PRODUCT
1528 void Compile::AliasType::print_on(outputStream* st) {
1529   if (index() < 10)
1530         st->print("@ <%d> ", index());
1531   else  st->print("@ <%d>",  index());
1532   st->print(is_rewritable() ? "   " : " RO");
1533   int offset = adr_type()->offset();
1534   if (offset == Type::OffsetBot)
1535         st->print(" +any");
1536   else  st->print(" +%-3d", offset);
1537   st->print(" in ");
1538   adr_type()->dump_on(st);
1539   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1540   if (field() != NULL && tjp) {
1541     if (tjp->klass()  != field()->holder() ||
1542         tjp->offset() != field()->offset_in_bytes()) {
1543       st->print(" != ");
1544       field()->print();
1545       st->print(" ***");
1546     }
1547   }
1548 }
1549 
1550 void print_alias_types() {
1551   Compile* C = Compile::current();
1552   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1553   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1554     C->alias_type(idx)->print_on(tty);
1555     tty->cr();
1556   }
1557 }
1558 #endif
1559 
1560 
1561 //----------------------------probe_alias_cache--------------------------------
1562 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1563   intptr_t key = (intptr_t) adr_type;
1564   key ^= key >> logAliasCacheSize;
1565   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1566 }
1567 
1568 
1569 //-----------------------------grow_alias_types--------------------------------
1570 void Compile::grow_alias_types() {
1571   const int old_ats  = _max_alias_types; // how many before?
1572   const int new_ats  = old_ats;          // how many more?
1573   const int grow_ats = old_ats+new_ats;  // how many now?
1574   _max_alias_types = grow_ats;
1575   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1576   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1577   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1578   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1579 }
1580 
1581 
1582 //--------------------------------find_alias_type------------------------------
1583 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1584   if (_AliasLevel == 0)
1585     return alias_type(AliasIdxBot);
1586 
1587   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1588   if (ace->_adr_type == adr_type) {
1589     return alias_type(ace->_index);
1590   }
1591 
1592   // Handle special cases.
1593   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1594   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1595 
1596   // Do it the slow way.
1597   const TypePtr* flat = flatten_alias_type(adr_type);
1598 
1599 #ifdef ASSERT
1600   {
1601     ResourceMark rm;
1602     assert(flat == flatten_alias_type(flat), "not idempotent: adr_type = %s; flat = %s => %s",
1603            Type::str(adr_type), Type::str(flat), Type::str(flatten_alias_type(flat)));
1604     assert(flat != TypePtr::BOTTOM, "cannot alias-analyze an untyped ptr: adr_type = %s",
1605            Type::str(adr_type));
1606     if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1607       const TypeOopPtr* foop = flat->is_oopptr();
1608       // Scalarizable allocations have exact klass always.
1609       bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1610       const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1611       assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type: foop = %s; xoop = %s",
1612              Type::str(foop), Type::str(xoop));
1613     }
1614   }
1615 #endif
1616 
1617   int idx = AliasIdxTop;
1618   for (int i = 0; i < num_alias_types(); i++) {
1619     if (alias_type(i)->adr_type() == flat) {
1620       idx = i;
1621       break;
1622     }
1623   }
1624 
1625   if (idx == AliasIdxTop) {
1626     if (no_create)  return NULL;
1627     // Grow the array if necessary.
1628     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1629     // Add a new alias type.
1630     idx = _num_alias_types++;
1631     _alias_types[idx]->Init(idx, flat);
1632     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1633     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1634     if (flat->isa_instptr()) {
1635       if (flat->offset() == java_lang_Class::klass_offset()
1636           && flat->is_instptr()->klass() == env()->Class_klass())
1637         alias_type(idx)->set_rewritable(false);
1638     }
1639     if (flat->isa_aryptr()) {
1640 #ifdef ASSERT
1641       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1642       // (T_BYTE has the weakest alignment and size restrictions...)
1643       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1644 #endif
1645       if (flat->offset() == TypePtr::OffsetBot) {
1646         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1647       }
1648     }
1649     if (flat->isa_klassptr()) {
1650       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1651         alias_type(idx)->set_rewritable(false);
1652       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1653         alias_type(idx)->set_rewritable(false);
1654       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1655         alias_type(idx)->set_rewritable(false);
1656       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1657         alias_type(idx)->set_rewritable(false);
1658       if (flat->offset() == in_bytes(Klass::secondary_super_cache_offset()))
1659         alias_type(idx)->set_rewritable(false);
1660     }
1661     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1662     // but the base pointer type is not distinctive enough to identify
1663     // references into JavaThread.)
1664 
1665     // Check for final fields.
1666     const TypeInstPtr* tinst = flat->isa_instptr();
1667     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1668       ciField* field;
1669       if (tinst->const_oop() != NULL &&
1670           tinst->klass() == ciEnv::current()->Class_klass() &&
1671           tinst->offset() >= (tinst->klass()->as_instance_klass()->layout_helper_size_in_bytes())) {
1672         // static field
1673         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1674         field = k->get_field_by_offset(tinst->offset(), true);
1675       } else {
1676         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1677         field = k->get_field_by_offset(tinst->offset(), false);
1678       }
1679       assert(field == NULL ||
1680              original_field == NULL ||
1681              (field->holder() == original_field->holder() &&
1682               field->offset() == original_field->offset() &&
1683               field->is_static() == original_field->is_static()), "wrong field?");
1684       // Set field() and is_rewritable() attributes.
1685       if (field != NULL)  alias_type(idx)->set_field(field);
1686     }
1687   }
1688 
1689   // Fill the cache for next time.
1690   ace->_adr_type = adr_type;
1691   ace->_index    = idx;
1692   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1693 
1694   // Might as well try to fill the cache for the flattened version, too.
1695   AliasCacheEntry* face = probe_alias_cache(flat);
1696   if (face->_adr_type == NULL) {
1697     face->_adr_type = flat;
1698     face->_index    = idx;
1699     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1700   }
1701 
1702   return alias_type(idx);
1703 }
1704 
1705 
1706 Compile::AliasType* Compile::alias_type(ciField* field) {
1707   const TypeOopPtr* t;
1708   if (field->is_static())
1709     t = TypeInstPtr::make(field->holder()->java_mirror());
1710   else
1711     t = TypeOopPtr::make_from_klass_raw(field->holder());
1712   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1713   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1714   return atp;
1715 }
1716 
1717 
1718 //------------------------------have_alias_type--------------------------------
1719 bool Compile::have_alias_type(const TypePtr* adr_type) {
1720   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1721   if (ace->_adr_type == adr_type) {
1722     return true;
1723   }
1724 
1725   // Handle special cases.
1726   if (adr_type == NULL)             return true;
1727   if (adr_type == TypePtr::BOTTOM)  return true;
1728 
1729   return find_alias_type(adr_type, true, NULL) != NULL;
1730 }
1731 
1732 //-----------------------------must_alias--------------------------------------
1733 // True if all values of the given address type are in the given alias category.
1734 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1735   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1736   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1737   if (alias_idx == AliasIdxTop)         return false; // the empty category
1738   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1739 
1740   // the only remaining possible overlap is identity
1741   int adr_idx = get_alias_index(adr_type);
1742   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1743   assert(adr_idx == alias_idx ||
1744          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1745           && adr_type                       != TypeOopPtr::BOTTOM),
1746          "should not be testing for overlap with an unsafe pointer");
1747   return adr_idx == alias_idx;
1748 }
1749 
1750 //------------------------------can_alias--------------------------------------
1751 // True if any values of the given address type are in the given alias category.
1752 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1753   if (alias_idx == AliasIdxTop)         return false; // the empty category
1754   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1755   // Known instance doesn't alias with bottom memory
1756   if (alias_idx == AliasIdxBot)         return !adr_type->is_known_instance();                   // the universal category
1757   if (adr_type->base() == Type::AnyPtr) return !C->get_adr_type(alias_idx)->is_known_instance(); // TypePtr::BOTTOM or its twins
1758 
1759   // the only remaining possible overlap is identity
1760   int adr_idx = get_alias_index(adr_type);
1761   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1762   return adr_idx == alias_idx;
1763 }
1764 
1765 //---------------------cleanup_loop_predicates-----------------------
1766 // Remove the opaque nodes that protect the predicates so that all unused
1767 // checks and uncommon_traps will be eliminated from the ideal graph
1768 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1769   if (predicate_count()==0) return;
1770   for (int i = predicate_count(); i > 0; i--) {
1771     Node * n = predicate_opaque1_node(i-1);
1772     assert(n->Opcode() == Op_Opaque1, "must be");
1773     igvn.replace_node(n, n->in(1));
1774   }
1775   assert(predicate_count()==0, "should be clean!");
1776 }
1777 
1778 void Compile::record_for_post_loop_opts_igvn(Node* n) {
1779   if (!n->for_post_loop_opts_igvn()) {
1780     assert(!_for_post_loop_igvn.contains(n), "duplicate");
1781     n->add_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
1782     _for_post_loop_igvn.append(n);
1783   }
1784 }
1785 
1786 void Compile::remove_from_post_loop_opts_igvn(Node* n) {
1787   n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
1788   _for_post_loop_igvn.remove(n);
1789 }
1790 
1791 void Compile::process_for_post_loop_opts_igvn(PhaseIterGVN& igvn) {
1792   // Verify that all previous optimizations produced a valid graph
1793   // at least to this point, even if no loop optimizations were done.
1794   PhaseIdealLoop::verify(igvn);
1795 
1796   C->set_post_loop_opts_phase(); // no more loop opts allowed
1797 
1798   assert(!C->major_progress(), "not cleared");
1799 
1800   if (_for_post_loop_igvn.length() > 0) {
1801     while (_for_post_loop_igvn.length() > 0) {
1802       Node* n = _for_post_loop_igvn.pop();
1803       n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
1804       igvn._worklist.push(n);
1805     }
1806     igvn.optimize();
1807     assert(_for_post_loop_igvn.length() == 0, "no more delayed nodes allowed");
1808 
1809     // Sometimes IGVN sets major progress (e.g., when processing loop nodes).
1810     if (C->major_progress()) {
1811       C->clear_major_progress(); // ensure that major progress is now clear
1812     }
1813   }
1814 }
1815 
1816 // StringOpts and late inlining of string methods
1817 void Compile::inline_string_calls(bool parse_time) {
1818   {
1819     // remove useless nodes to make the usage analysis simpler
1820     ResourceMark rm;
1821     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1822   }
1823 
1824   {
1825     ResourceMark rm;
1826     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1827     PhaseStringOpts pso(initial_gvn(), for_igvn());
1828     print_method(PHASE_AFTER_STRINGOPTS, 3);
1829   }
1830 
1831   // now inline anything that we skipped the first time around
1832   if (!parse_time) {
1833     _late_inlines_pos = _late_inlines.length();
1834   }
1835 
1836   while (_string_late_inlines.length() > 0) {
1837     CallGenerator* cg = _string_late_inlines.pop();
1838     cg->do_late_inline();
1839     if (failing())  return;
1840   }
1841   _string_late_inlines.trunc_to(0);
1842 }
1843 
1844 // Late inlining of boxing methods
1845 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1846   if (_boxing_late_inlines.length() > 0) {
1847     assert(has_boxed_value(), "inconsistent");
1848 
1849     PhaseGVN* gvn = initial_gvn();
1850     set_inlining_incrementally(true);
1851 
1852     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1853     for_igvn()->clear();
1854     gvn->replace_with(&igvn);
1855 
1856     _late_inlines_pos = _late_inlines.length();
1857 
1858     while (_boxing_late_inlines.length() > 0) {
1859       CallGenerator* cg = _boxing_late_inlines.pop();
1860       cg->do_late_inline();
1861       if (failing())  return;
1862     }
1863     _boxing_late_inlines.trunc_to(0);
1864 
1865     inline_incrementally_cleanup(igvn);
1866 
1867     set_inlining_incrementally(false);
1868   }
1869 }
1870 
1871 bool Compile::inline_incrementally_one() {
1872   assert(IncrementalInline, "incremental inlining should be on");
1873 
1874   TracePhase tp("incrementalInline_inline", &timers[_t_incrInline_inline]);
1875 
1876   set_inlining_progress(false);
1877   set_do_cleanup(false);
1878 
1879   for (int i = 0; i < _late_inlines.length(); i++) {
1880     _late_inlines_pos = i+1;
1881     CallGenerator* cg = _late_inlines.at(i);
1882     bool does_dispatch = cg->is_virtual_late_inline() || cg->is_mh_late_inline();
1883     if (inlining_incrementally() || does_dispatch) { // a call can be either inlined or strength-reduced to a direct call
1884       cg->do_late_inline();
1885       assert(_late_inlines.at(i) == cg, "no insertions before current position allowed");
1886       if (failing()) {
1887         return false;
1888       } else if (inlining_progress()) {
1889         _late_inlines_pos = i+1; // restore the position in case new elements were inserted
1890         print_method(PHASE_INCREMENTAL_INLINE_STEP, cg->call_node(), 3);
1891         break; // process one call site at a time
1892       }
1893     } else {
1894       // Ignore late inline direct calls when inlining is not allowed.
1895       // They are left in the late inline list when node budget is exhausted until the list is fully drained.
1896     }
1897   }
1898   // Remove processed elements.
1899   _late_inlines.remove_till(_late_inlines_pos);
1900   _late_inlines_pos = 0;
1901 
1902   assert(inlining_progress() || _late_inlines.length() == 0, "no progress");
1903 
1904   bool needs_cleanup = do_cleanup() || over_inlining_cutoff();
1905 
1906   set_inlining_progress(false);
1907   set_do_cleanup(false);
1908 
1909   bool force_cleanup = directive()->IncrementalInlineForceCleanupOption;
1910   return (_late_inlines.length() > 0) && !needs_cleanup && !force_cleanup;
1911 }
1912 
1913 void Compile::inline_incrementally_cleanup(PhaseIterGVN& igvn) {
1914   {
1915     TracePhase tp("incrementalInline_pru", &timers[_t_incrInline_pru]);
1916     ResourceMark rm;
1917     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1918   }
1919   {
1920     TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
1921     igvn = PhaseIterGVN(initial_gvn());
1922     igvn.optimize();
1923   }
1924   print_method(PHASE_INCREMENTAL_INLINE_CLEANUP, 3);
1925 }
1926 
1927 // Perform incremental inlining until bound on number of live nodes is reached
1928 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1929   TracePhase tp("incrementalInline", &timers[_t_incrInline]);
1930 
1931   set_inlining_incrementally(true);
1932   uint low_live_nodes = 0;
1933 
1934   while (_late_inlines.length() > 0) {
1935     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1936       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
1937         TracePhase tp("incrementalInline_ideal", &timers[_t_incrInline_ideal]);
1938         // PhaseIdealLoop is expensive so we only try it once we are
1939         // out of live nodes and we only try it again if the previous
1940         // helped got the number of nodes down significantly
1941         PhaseIdealLoop::optimize(igvn, LoopOptsNone);
1942         if (failing())  return;
1943         low_live_nodes = live_nodes();
1944         _major_progress = true;
1945       }
1946 
1947       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1948         bool do_print_inlining = print_inlining() || print_intrinsics();
1949         if (do_print_inlining || log() != NULL) {
1950           // Print inlining message for candidates that we couldn't inline for lack of space.
1951           for (int i = 0; i < _late_inlines.length(); i++) {
1952             CallGenerator* cg = _late_inlines.at(i);
1953             const char* msg = "live nodes > LiveNodeCountInliningCutoff";
1954             if (do_print_inlining) {
1955               cg->print_inlining_late(msg);
1956             }
1957             log_late_inline_failure(cg, msg);
1958           }
1959         }
1960         break; // finish
1961       }
1962     }
1963 
1964     for_igvn()->clear();
1965     initial_gvn()->replace_with(&igvn);
1966 
1967     while (inline_incrementally_one()) {
1968       assert(!failing(), "inconsistent");
1969     }
1970     if (failing())  return;
1971 
1972     inline_incrementally_cleanup(igvn);
1973 
1974     print_method(PHASE_INCREMENTAL_INLINE_STEP, 3);
1975 
1976     if (failing())  return;
1977 
1978     if (_late_inlines.length() == 0) {
1979       break; // no more progress
1980     }
1981   }
1982   assert( igvn._worklist.size() == 0, "should be done with igvn" );
1983 
1984   if (_string_late_inlines.length() > 0) {
1985     assert(has_stringbuilder(), "inconsistent");
1986     for_igvn()->clear();
1987     initial_gvn()->replace_with(&igvn);
1988 
1989     inline_string_calls(false);
1990 
1991     if (failing())  return;
1992 
1993     inline_incrementally_cleanup(igvn);
1994   }
1995 
1996   set_inlining_incrementally(false);
1997 }
1998 
1999 void Compile::process_late_inline_calls_no_inline(PhaseIterGVN& igvn) {
2000   // "inlining_incrementally() == false" is used to signal that no inlining is allowed
2001   // (see LateInlineVirtualCallGenerator::do_late_inline_check() for details).
2002   // Tracking and verification of modified nodes is disabled by setting "_modified_nodes == NULL"
2003   // as if "inlining_incrementally() == true" were set.
2004   assert(inlining_incrementally() == false, "not allowed");
2005   assert(_modified_nodes == NULL, "not allowed");
2006   assert(_late_inlines.length() > 0, "sanity");
2007 
2008   while (_late_inlines.length() > 0) {
2009     for_igvn()->clear();
2010     initial_gvn()->replace_with(&igvn);
2011 
2012     while (inline_incrementally_one()) {
2013       assert(!failing(), "inconsistent");
2014     }
2015     if (failing())  return;
2016 
2017     inline_incrementally_cleanup(igvn);
2018   }
2019 }
2020 
2021 bool Compile::optimize_loops(PhaseIterGVN& igvn, LoopOptsMode mode) {
2022   if (_loop_opts_cnt > 0) {
2023     debug_only( int cnt = 0; );
2024     while (major_progress() && (_loop_opts_cnt > 0)) {
2025       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2026       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2027       PhaseIdealLoop::optimize(igvn, mode);
2028       _loop_opts_cnt--;
2029       if (failing())  return false;
2030       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2031     }
2032   }
2033   return true;
2034 }
2035 
2036 // Remove edges from "root" to each SafePoint at a backward branch.
2037 // They were inserted during parsing (see add_safepoint()) to make
2038 // infinite loops without calls or exceptions visible to root, i.e.,
2039 // useful.
2040 void Compile::remove_root_to_sfpts_edges(PhaseIterGVN& igvn) {
2041   Node *r = root();
2042   if (r != NULL) {
2043     for (uint i = r->req(); i < r->len(); ++i) {
2044       Node *n = r->in(i);
2045       if (n != NULL && n->is_SafePoint()) {
2046         r->rm_prec(i);
2047         if (n->outcnt() == 0) {
2048           igvn.remove_dead_node(n);
2049         }
2050         --i;
2051       }
2052     }
2053     // Parsing may have added top inputs to the root node (Path
2054     // leading to the Halt node proven dead). Make sure we get a
2055     // chance to clean them up.
2056     igvn._worklist.push(r);
2057     igvn.optimize();
2058   }
2059 }
2060 
2061 //------------------------------Optimize---------------------------------------
2062 // Given a graph, optimize it.
2063 void Compile::Optimize() {
2064   TracePhase tp("optimizer", &timers[_t_optimizer]);
2065 
2066 #ifndef PRODUCT
2067   if (env()->break_at_compile()) {
2068     BREAKPOINT;
2069   }
2070 
2071 #endif
2072 
2073   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2074 #ifdef ASSERT
2075   bs->verify_gc_barriers(this, BarrierSetC2::BeforeOptimize);
2076 #endif
2077 
2078   ResourceMark rm;
2079 
2080   print_inlining_reinit();
2081 
2082   NOT_PRODUCT( verify_graph_edges(); )
2083 
2084   print_method(PHASE_AFTER_PARSING);
2085 
2086  {
2087   // Iterative Global Value Numbering, including ideal transforms
2088   // Initialize IterGVN with types and values from parse-time GVN
2089   PhaseIterGVN igvn(initial_gvn());
2090 #ifdef ASSERT
2091   _modified_nodes = new (comp_arena()) Unique_Node_List(comp_arena());
2092 #endif
2093   {
2094     TracePhase tp("iterGVN", &timers[_t_iterGVN]);
2095     igvn.optimize();
2096   }
2097 
2098   if (failing())  return;
2099 
2100   print_method(PHASE_ITER_GVN1, 2);
2101 
2102   inline_incrementally(igvn);
2103 
2104   print_method(PHASE_INCREMENTAL_INLINE, 2);
2105 
2106   if (failing())  return;
2107 
2108   if (eliminate_boxing()) {
2109     // Inline valueOf() methods now.
2110     inline_boxing_calls(igvn);
2111 
2112     if (AlwaysIncrementalInline) {
2113       inline_incrementally(igvn);
2114     }
2115 
2116     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2117 
2118     if (failing())  return;
2119   }
2120 
2121   // Remove the speculative part of types and clean up the graph from
2122   // the extra CastPP nodes whose only purpose is to carry them. Do
2123   // that early so that optimizations are not disrupted by the extra
2124   // CastPP nodes.
2125   remove_speculative_types(igvn);
2126 
2127   // No more new expensive nodes will be added to the list from here
2128   // so keep only the actual candidates for optimizations.
2129   cleanup_expensive_nodes(igvn);
2130 
2131   assert(EnableVectorSupport || !has_vbox_nodes(), "sanity");
2132   if (EnableVectorSupport && has_vbox_nodes()) {
2133     TracePhase tp("", &timers[_t_vector]);
2134     PhaseVector pv(igvn);
2135     pv.optimize_vector_boxes();
2136 
2137     print_method(PHASE_ITER_GVN_AFTER_VECTOR, 2);
2138   }
2139   assert(!has_vbox_nodes(), "sanity");
2140 
2141   if (!failing() && RenumberLiveNodes && live_nodes() + NodeLimitFudgeFactor < unique()) {
2142     Compile::TracePhase tp("", &timers[_t_renumberLive]);
2143     initial_gvn()->replace_with(&igvn);
2144     Unique_Node_List* old_worklist = for_igvn();
2145     old_worklist->clear();
2146     Unique_Node_List new_worklist(C->comp_arena());
2147     {
2148       ResourceMark rm;
2149       PhaseRenumberLive prl = PhaseRenumberLive(initial_gvn(), for_igvn(), &new_worklist);
2150     }
2151     Unique_Node_List* save_for_igvn = for_igvn();
2152     set_for_igvn(&new_worklist);
2153     igvn = PhaseIterGVN(initial_gvn());
2154     igvn.optimize();
2155     set_for_igvn(old_worklist); // new_worklist is dead beyond this point
2156   }
2157 
2158   // Now that all inlining is over and no PhaseRemoveUseless will run, cut edge from root to loop
2159   // safepoints
2160   remove_root_to_sfpts_edges(igvn);
2161 
2162   // Perform escape analysis
2163   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2164     if (has_loops()) {
2165       // Cleanup graph (remove dead nodes).
2166       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2167       PhaseIdealLoop::optimize(igvn, LoopOptsMaxUnroll);
2168       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2169       if (failing())  return;
2170     }
2171     ConnectionGraph::do_analysis(this, &igvn);
2172 
2173     if (failing())  return;
2174 
2175     // Optimize out fields loads from scalar replaceable allocations.
2176     igvn.optimize();
2177     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2178 
2179     if (failing())  return;
2180 
2181     if (congraph() != NULL && macro_count() > 0) {
2182       TracePhase tp("macroEliminate", &timers[_t_macroEliminate]);
2183       PhaseMacroExpand mexp(igvn);
2184       mexp.eliminate_macro_nodes();
2185       igvn.set_delay_transform(false);
2186 
2187       igvn.optimize();
2188       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2189 
2190       if (failing())  return;
2191     }
2192   }
2193 
2194   // Loop transforms on the ideal graph.  Range Check Elimination,
2195   // peeling, unrolling, etc.
2196 
2197   // Set loop opts counter
2198   if((_loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2199     {
2200       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2201       PhaseIdealLoop::optimize(igvn, LoopOptsDefault);
2202       _loop_opts_cnt--;
2203       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2204       if (failing())  return;
2205     }
2206     // Loop opts pass if partial peeling occurred in previous pass
2207     if(PartialPeelLoop && major_progress() && (_loop_opts_cnt > 0)) {
2208       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2209       PhaseIdealLoop::optimize(igvn, LoopOptsSkipSplitIf);
2210       _loop_opts_cnt--;
2211       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2212       if (failing())  return;
2213     }
2214     // Loop opts pass for loop-unrolling before CCP
2215     if(major_progress() && (_loop_opts_cnt > 0)) {
2216       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2217       PhaseIdealLoop::optimize(igvn, LoopOptsSkipSplitIf);
2218       _loop_opts_cnt--;
2219       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2220     }
2221     if (!failing()) {
2222       // Verify that last round of loop opts produced a valid graph
2223       PhaseIdealLoop::verify(igvn);
2224     }
2225   }
2226   if (failing())  return;
2227 
2228   // Conditional Constant Propagation;
2229   PhaseCCP ccp( &igvn );
2230   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2231   {
2232     TracePhase tp("ccp", &timers[_t_ccp]);
2233     ccp.do_transform();
2234   }
2235   print_method(PHASE_CCP1, 2);
2236 
2237   assert( true, "Break here to ccp.dump_old2new_map()");
2238 
2239   // Iterative Global Value Numbering, including ideal transforms
2240   {
2241     TracePhase tp("iterGVN2", &timers[_t_iterGVN2]);
2242     igvn = ccp;
2243     igvn.optimize();
2244   }
2245   print_method(PHASE_ITER_GVN2, 2);
2246 
2247   if (failing())  return;
2248 
2249   // Loop transforms on the ideal graph.  Range Check Elimination,
2250   // peeling, unrolling, etc.
2251   if (!optimize_loops(igvn, LoopOptsDefault)) {
2252     return;
2253   }
2254 
2255   if (failing())  return;
2256 
2257   C->clear_major_progress(); // ensure that major progress is now clear
2258 
2259   process_for_post_loop_opts_igvn(igvn);
2260 
2261 #ifdef ASSERT
2262   bs->verify_gc_barriers(this, BarrierSetC2::BeforeMacroExpand);
2263 #endif
2264 
2265   {
2266     TracePhase tp("macroExpand", &timers[_t_macroExpand]);
2267     PhaseMacroExpand  mex(igvn);
2268     if (mex.expand_macro_nodes()) {
2269       assert(failing(), "must bail out w/ explicit message");
2270       return;
2271     }
2272     print_method(PHASE_MACRO_EXPANSION, 2);
2273   }
2274 
2275   {
2276     TracePhase tp("barrierExpand", &timers[_t_barrierExpand]);
2277     if (bs->expand_barriers(this, igvn)) {
2278       assert(failing(), "must bail out w/ explicit message");
2279       return;
2280     }
2281     print_method(PHASE_BARRIER_EXPANSION, 2);
2282   }
2283 
2284   if (C->max_vector_size() > 0) {
2285     C->optimize_logic_cones(igvn);
2286     igvn.optimize();
2287   }
2288 
2289   DEBUG_ONLY( _modified_nodes = NULL; )
2290 
2291   assert(igvn._worklist.size() == 0, "not empty");
2292 
2293   assert(_late_inlines.length() == 0 || IncrementalInlineMH || IncrementalInlineVirtual, "not empty");
2294 
2295   if (_late_inlines.length() > 0) {
2296     // More opportunities to optimize virtual and MH calls.
2297     // Though it's maybe too late to perform inlining, strength-reducing them to direct calls is still an option.
2298     process_late_inline_calls_no_inline(igvn);
2299   }
2300  } // (End scope of igvn; run destructor if necessary for asserts.)
2301 
2302  check_no_dead_use();
2303 
2304  process_print_inlining();
2305 
2306  // A method with only infinite loops has no edges entering loops from root
2307  {
2308    TracePhase tp("graphReshape", &timers[_t_graphReshaping]);
2309    if (final_graph_reshaping()) {
2310      assert(failing(), "must bail out w/ explicit message");
2311      return;
2312    }
2313  }
2314 
2315  print_method(PHASE_OPTIMIZE_FINISHED, 2);
2316  DEBUG_ONLY(set_phase_optimize_finished();)
2317 }
2318 
2319 #ifdef ASSERT
2320 void Compile::check_no_dead_use() const {
2321   ResourceMark rm;
2322   Unique_Node_List wq;
2323   wq.push(root());
2324   for (uint i = 0; i < wq.size(); ++i) {
2325     Node* n = wq.at(i);
2326     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2327       Node* u = n->fast_out(j);
2328       if (u->outcnt() == 0 && !u->is_Con()) {
2329         u->dump();
2330         fatal("no reachable node should have no use");
2331       }
2332       wq.push(u);
2333     }
2334   }
2335 }
2336 #endif
2337 
2338 void Compile::inline_vector_reboxing_calls() {
2339   if (C->_vector_reboxing_late_inlines.length() > 0) {
2340     _late_inlines_pos = C->_late_inlines.length();
2341     while (_vector_reboxing_late_inlines.length() > 0) {
2342       CallGenerator* cg = _vector_reboxing_late_inlines.pop();
2343       cg->do_late_inline();
2344       if (failing())  return;
2345       print_method(PHASE_INLINE_VECTOR_REBOX, cg->call_node());
2346     }
2347     _vector_reboxing_late_inlines.trunc_to(0);
2348   }
2349 }
2350 
2351 bool Compile::has_vbox_nodes() {
2352   if (C->_vector_reboxing_late_inlines.length() > 0) {
2353     return true;
2354   }
2355   for (int macro_idx = C->macro_count() - 1; macro_idx >= 0; macro_idx--) {
2356     Node * n = C->macro_node(macro_idx);
2357     assert(n->is_macro(), "only macro nodes expected here");
2358     if (n->Opcode() == Op_VectorUnbox || n->Opcode() == Op_VectorBox || n->Opcode() == Op_VectorBoxAllocate) {
2359       return true;
2360     }
2361   }
2362   return false;
2363 }
2364 
2365 //---------------------------- Bitwise operation packing optimization ---------------------------
2366 
2367 static bool is_vector_unary_bitwise_op(Node* n) {
2368   return n->Opcode() == Op_XorV &&
2369          n->req() == 2 &&
2370          VectorNode::is_vector_bitwise_not_pattern(n);
2371 }
2372 
2373 static bool is_vector_binary_bitwise_op(Node* n) {
2374   switch (n->Opcode()) {
2375     case Op_AndV:
2376     case Op_OrV:
2377       return n->req() == 2;
2378 
2379     case Op_XorV:
2380       return !is_vector_unary_bitwise_op(n);
2381 
2382     default:
2383       return false;
2384   }
2385 }
2386 
2387 static bool is_vector_ternary_bitwise_op(Node* n) {
2388   return n->Opcode() == Op_MacroLogicV;
2389 }
2390 
2391 static bool is_vector_bitwise_op(Node* n) {
2392   return is_vector_unary_bitwise_op(n)  ||
2393          is_vector_binary_bitwise_op(n) ||
2394          is_vector_ternary_bitwise_op(n);
2395 }
2396 
2397 static bool is_vector_bitwise_cone_root(Node* n) {
2398   if (n->bottom_type()->isa_vectmask() || !is_vector_bitwise_op(n)) {
2399     return false;
2400   }
2401   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2402     if (is_vector_bitwise_op(n->fast_out(i))) {
2403       return false;
2404     }
2405   }
2406   return true;
2407 }
2408 
2409 static uint collect_unique_inputs(Node* n, Unique_Node_List& partition, Unique_Node_List& inputs) {
2410   uint cnt = 0;
2411   if (is_vector_bitwise_op(n)) {
2412     if (VectorNode::is_vector_bitwise_not_pattern(n)) {
2413       for (uint i = 1; i < n->req(); i++) {
2414         Node* in = n->in(i);
2415         bool skip = VectorNode::is_all_ones_vector(in);
2416         if (!skip && !inputs.member(in)) {
2417           inputs.push(in);
2418           cnt++;
2419         }
2420       }
2421       assert(cnt <= 1, "not unary");
2422     } else {
2423       uint last_req = n->req();
2424       if (is_vector_ternary_bitwise_op(n)) {
2425         last_req = n->req() - 1; // skip last input
2426       }
2427       for (uint i = 1; i < last_req; i++) {
2428         Node* def = n->in(i);
2429         if (!inputs.member(def)) {
2430           inputs.push(def);
2431           cnt++;
2432         }
2433       }
2434     }
2435     partition.push(n);
2436   } else { // not a bitwise operations
2437     if (!inputs.member(n)) {
2438       inputs.push(n);
2439       cnt++;
2440     }
2441   }
2442   return cnt;
2443 }
2444 
2445 void Compile::collect_logic_cone_roots(Unique_Node_List& list) {
2446   Unique_Node_List useful_nodes;
2447   C->identify_useful_nodes(useful_nodes);
2448 
2449   for (uint i = 0; i < useful_nodes.size(); i++) {
2450     Node* n = useful_nodes.at(i);
2451     if (is_vector_bitwise_cone_root(n)) {
2452       list.push(n);
2453     }
2454   }
2455 }
2456 
2457 Node* Compile::xform_to_MacroLogicV(PhaseIterGVN& igvn,
2458                                     const TypeVect* vt,
2459                                     Unique_Node_List& partition,
2460                                     Unique_Node_List& inputs) {
2461   assert(partition.size() == 2 || partition.size() == 3, "not supported");
2462   assert(inputs.size()    == 2 || inputs.size()    == 3, "not supported");
2463   assert(Matcher::match_rule_supported_vector(Op_MacroLogicV, vt->length(), vt->element_basic_type()), "not supported");
2464 
2465   Node* in1 = inputs.at(0);
2466   Node* in2 = inputs.at(1);
2467   Node* in3 = (inputs.size() == 3 ? inputs.at(2) : in2);
2468 
2469   uint func = compute_truth_table(partition, inputs);
2470   return igvn.transform(MacroLogicVNode::make(igvn, in3, in2, in1, func, vt));
2471 }
2472 
2473 static uint extract_bit(uint func, uint pos) {
2474   return (func & (1 << pos)) >> pos;
2475 }
2476 
2477 //
2478 //  A macro logic node represents a truth table. It has 4 inputs,
2479 //  First three inputs corresponds to 3 columns of a truth table
2480 //  and fourth input captures the logic function.
2481 //
2482 //  eg.  fn = (in1 AND in2) OR in3;
2483 //
2484 //      MacroNode(in1,in2,in3,fn)
2485 //
2486 //  -----------------
2487 //  in1 in2 in3  fn
2488 //  -----------------
2489 //  0    0   0    0
2490 //  0    0   1    1
2491 //  0    1   0    0
2492 //  0    1   1    1
2493 //  1    0   0    0
2494 //  1    0   1    1
2495 //  1    1   0    1
2496 //  1    1   1    1
2497 //
2498 
2499 uint Compile::eval_macro_logic_op(uint func, uint in1 , uint in2, uint in3) {
2500   int res = 0;
2501   for (int i = 0; i < 8; i++) {
2502     int bit1 = extract_bit(in1, i);
2503     int bit2 = extract_bit(in2, i);
2504     int bit3 = extract_bit(in3, i);
2505 
2506     int func_bit_pos = (bit1 << 2 | bit2 << 1 | bit3);
2507     int func_bit = extract_bit(func, func_bit_pos);
2508 
2509     res |= func_bit << i;
2510   }
2511   return res;
2512 }
2513 
2514 static uint eval_operand(Node* n, ResourceHashtable<Node*,uint>& eval_map) {
2515   assert(n != NULL, "");
2516   assert(eval_map.contains(n), "absent");
2517   return *(eval_map.get(n));
2518 }
2519 
2520 static void eval_operands(Node* n,
2521                           uint& func1, uint& func2, uint& func3,
2522                           ResourceHashtable<Node*,uint>& eval_map) {
2523   assert(is_vector_bitwise_op(n), "");
2524 
2525   if (is_vector_unary_bitwise_op(n)) {
2526     Node* opnd = n->in(1);
2527     if (VectorNode::is_vector_bitwise_not_pattern(n) && VectorNode::is_all_ones_vector(opnd)) {
2528       opnd = n->in(2);
2529     }
2530     func1 = eval_operand(opnd, eval_map);
2531   } else if (is_vector_binary_bitwise_op(n)) {
2532     func1 = eval_operand(n->in(1), eval_map);
2533     func2 = eval_operand(n->in(2), eval_map);
2534   } else {
2535     assert(is_vector_ternary_bitwise_op(n), "unknown operation");
2536     func1 = eval_operand(n->in(1), eval_map);
2537     func2 = eval_operand(n->in(2), eval_map);
2538     func3 = eval_operand(n->in(3), eval_map);
2539   }
2540 }
2541 
2542 uint Compile::compute_truth_table(Unique_Node_List& partition, Unique_Node_List& inputs) {
2543   assert(inputs.size() <= 3, "sanity");
2544   ResourceMark rm;
2545   uint res = 0;
2546   ResourceHashtable<Node*,uint> eval_map;
2547 
2548   // Populate precomputed functions for inputs.
2549   // Each input corresponds to one column of 3 input truth-table.
2550   uint input_funcs[] = { 0xAA,   // (_, _, a) -> a
2551                          0xCC,   // (_, b, _) -> b
2552                          0xF0 }; // (c, _, _) -> c
2553   for (uint i = 0; i < inputs.size(); i++) {
2554     eval_map.put(inputs.at(i), input_funcs[i]);
2555   }
2556 
2557   for (uint i = 0; i < partition.size(); i++) {
2558     Node* n = partition.at(i);
2559 
2560     uint func1 = 0, func2 = 0, func3 = 0;
2561     eval_operands(n, func1, func2, func3, eval_map);
2562 
2563     switch (n->Opcode()) {
2564       case Op_OrV:
2565         assert(func3 == 0, "not binary");
2566         res = func1 | func2;
2567         break;
2568       case Op_AndV:
2569         assert(func3 == 0, "not binary");
2570         res = func1 & func2;
2571         break;
2572       case Op_XorV:
2573         if (VectorNode::is_vector_bitwise_not_pattern(n)) {
2574           assert(func2 == 0 && func3 == 0, "not unary");
2575           res = (~func1) & 0xFF;
2576         } else {
2577           assert(func3 == 0, "not binary");
2578           res = func1 ^ func2;
2579         }
2580         break;
2581       case Op_MacroLogicV:
2582         // Ordering of inputs may change during evaluation of sub-tree
2583         // containing MacroLogic node as a child node, thus a re-evaluation
2584         // makes sure that function is evaluated in context of current
2585         // inputs.
2586         res = eval_macro_logic_op(n->in(4)->get_int(), func1, func2, func3);
2587         break;
2588 
2589       default: assert(false, "not supported: %s", n->Name());
2590     }
2591     assert(res <= 0xFF, "invalid");
2592     eval_map.put(n, res);
2593   }
2594   return res;
2595 }
2596 
2597 bool Compile::compute_logic_cone(Node* n, Unique_Node_List& partition, Unique_Node_List& inputs) {
2598   assert(partition.size() == 0, "not empty");
2599   assert(inputs.size() == 0, "not empty");
2600   if (is_vector_ternary_bitwise_op(n)) {
2601     return false;
2602   }
2603 
2604   bool is_unary_op = is_vector_unary_bitwise_op(n);
2605   if (is_unary_op) {
2606     assert(collect_unique_inputs(n, partition, inputs) == 1, "not unary");
2607     return false; // too few inputs
2608   }
2609 
2610   assert(is_vector_binary_bitwise_op(n), "not binary");
2611   Node* in1 = n->in(1);
2612   Node* in2 = n->in(2);
2613 
2614   int in1_unique_inputs_cnt = collect_unique_inputs(in1, partition, inputs);
2615   int in2_unique_inputs_cnt = collect_unique_inputs(in2, partition, inputs);
2616   partition.push(n);
2617 
2618   // Too many inputs?
2619   if (inputs.size() > 3) {
2620     partition.clear();
2621     inputs.clear();
2622     { // Recompute in2 inputs
2623       Unique_Node_List not_used;
2624       in2_unique_inputs_cnt = collect_unique_inputs(in2, not_used, not_used);
2625     }
2626     // Pick the node with minimum number of inputs.
2627     if (in1_unique_inputs_cnt >= 3 && in2_unique_inputs_cnt >= 3) {
2628       return false; // still too many inputs
2629     }
2630     // Recompute partition & inputs.
2631     Node* child       = (in1_unique_inputs_cnt < in2_unique_inputs_cnt ? in1 : in2);
2632     collect_unique_inputs(child, partition, inputs);
2633 
2634     Node* other_input = (in1_unique_inputs_cnt < in2_unique_inputs_cnt ? in2 : in1);
2635     inputs.push(other_input);
2636 
2637     partition.push(n);
2638   }
2639 
2640   return (partition.size() == 2 || partition.size() == 3) &&
2641          (inputs.size()    == 2 || inputs.size()    == 3);
2642 }
2643 
2644 
2645 void Compile::process_logic_cone_root(PhaseIterGVN &igvn, Node *n, VectorSet &visited) {
2646   assert(is_vector_bitwise_op(n), "not a root");
2647 
2648   visited.set(n->_idx);
2649 
2650   // 1) Do a DFS walk over the logic cone.
2651   for (uint i = 1; i < n->req(); i++) {
2652     Node* in = n->in(i);
2653     if (!visited.test(in->_idx) && is_vector_bitwise_op(in)) {
2654       process_logic_cone_root(igvn, in, visited);
2655     }
2656   }
2657 
2658   // 2) Bottom up traversal: Merge node[s] with
2659   // the parent to form macro logic node.
2660   Unique_Node_List partition;
2661   Unique_Node_List inputs;
2662   if (compute_logic_cone(n, partition, inputs)) {
2663     const TypeVect* vt = n->bottom_type()->is_vect();
2664     Node* macro_logic = xform_to_MacroLogicV(igvn, vt, partition, inputs);
2665     igvn.replace_node(n, macro_logic);
2666   }
2667 }
2668 
2669 void Compile::optimize_logic_cones(PhaseIterGVN &igvn) {
2670   ResourceMark rm;
2671   if (Matcher::match_rule_supported(Op_MacroLogicV)) {
2672     Unique_Node_List list;
2673     collect_logic_cone_roots(list);
2674 
2675     while (list.size() > 0) {
2676       Node* n = list.pop();
2677       const TypeVect* vt = n->bottom_type()->is_vect();
2678       bool supported = Matcher::match_rule_supported_vector(Op_MacroLogicV, vt->length(), vt->element_basic_type());
2679       if (supported) {
2680         VectorSet visited(comp_arena());
2681         process_logic_cone_root(igvn, n, visited);
2682       }
2683     }
2684   }
2685 }
2686 
2687 //------------------------------Code_Gen---------------------------------------
2688 // Given a graph, generate code for it
2689 void Compile::Code_Gen() {
2690   if (failing()) {
2691     return;
2692   }
2693 
2694   // Perform instruction selection.  You might think we could reclaim Matcher
2695   // memory PDQ, but actually the Matcher is used in generating spill code.
2696   // Internals of the Matcher (including some VectorSets) must remain live
2697   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2698   // set a bit in reclaimed memory.
2699 
2700   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2701   // nodes.  Mapping is only valid at the root of each matched subtree.
2702   NOT_PRODUCT( verify_graph_edges(); )
2703 
2704   Matcher matcher;
2705   _matcher = &matcher;
2706   {
2707     TracePhase tp("matcher", &timers[_t_matcher]);
2708     matcher.match();
2709     if (failing()) {
2710       return;
2711     }
2712   }
2713   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2714   // nodes.  Mapping is only valid at the root of each matched subtree.
2715   NOT_PRODUCT( verify_graph_edges(); )
2716 
2717   // If you have too many nodes, or if matching has failed, bail out
2718   check_node_count(0, "out of nodes matching instructions");
2719   if (failing()) {
2720     return;
2721   }
2722 
2723   print_method(PHASE_MATCHING, 2);
2724 
2725   // Build a proper-looking CFG
2726   PhaseCFG cfg(node_arena(), root(), matcher);
2727   _cfg = &cfg;
2728   {
2729     TracePhase tp("scheduler", &timers[_t_scheduler]);
2730     bool success = cfg.do_global_code_motion();
2731     if (!success) {
2732       return;
2733     }
2734 
2735     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2736     NOT_PRODUCT( verify_graph_edges(); )
2737     cfg.verify();
2738   }
2739 
2740   PhaseChaitin regalloc(unique(), cfg, matcher, false);
2741   _regalloc = &regalloc;
2742   {
2743     TracePhase tp("regalloc", &timers[_t_registerAllocation]);
2744     // Perform register allocation.  After Chaitin, use-def chains are
2745     // no longer accurate (at spill code) and so must be ignored.
2746     // Node->LRG->reg mappings are still accurate.
2747     _regalloc->Register_Allocate();
2748 
2749     // Bail out if the allocator builds too many nodes
2750     if (failing()) {
2751       return;
2752     }
2753   }
2754 
2755   // Prior to register allocation we kept empty basic blocks in case the
2756   // the allocator needed a place to spill.  After register allocation we
2757   // are not adding any new instructions.  If any basic block is empty, we
2758   // can now safely remove it.
2759   {
2760     TracePhase tp("blockOrdering", &timers[_t_blockOrdering]);
2761     cfg.remove_empty_blocks();
2762     if (do_freq_based_layout()) {
2763       PhaseBlockLayout layout(cfg);
2764     } else {
2765       cfg.set_loop_alignment();
2766     }
2767     cfg.fixup_flow();
2768   }
2769 
2770   // Apply peephole optimizations
2771   if( OptoPeephole ) {
2772     TracePhase tp("peephole", &timers[_t_peephole]);
2773     PhasePeephole peep( _regalloc, cfg);
2774     peep.do_transform();
2775   }
2776 
2777   // Do late expand if CPU requires this.
2778   if (Matcher::require_postalloc_expand) {
2779     TracePhase tp("postalloc_expand", &timers[_t_postalloc_expand]);
2780     cfg.postalloc_expand(_regalloc);
2781   }
2782 
2783   // Convert Nodes to instruction bits in a buffer
2784   {
2785     TracePhase tp("output", &timers[_t_output]);
2786     PhaseOutput output;
2787     output.Output();
2788     if (failing())  return;
2789     output.install();
2790   }
2791 
2792   print_method(PHASE_FINAL_CODE);
2793 
2794   // He's dead, Jim.
2795   _cfg     = (PhaseCFG*)((intptr_t)0xdeadbeef);
2796   _regalloc = (PhaseChaitin*)((intptr_t)0xdeadbeef);
2797 }
2798 
2799 //------------------------------Final_Reshape_Counts---------------------------
2800 // This class defines counters to help identify when a method
2801 // may/must be executed using hardware with only 24-bit precision.
2802 struct Final_Reshape_Counts : public StackObj {
2803   int  _call_count;             // count non-inlined 'common' calls
2804   int  _float_count;            // count float ops requiring 24-bit precision
2805   int  _double_count;           // count double ops requiring more precision
2806   int  _java_call_count;        // count non-inlined 'java' calls
2807   int  _inner_loop_count;       // count loops which need alignment
2808   VectorSet _visited;           // Visitation flags
2809   Node_List _tests;             // Set of IfNodes & PCTableNodes
2810 
2811   Final_Reshape_Counts() :
2812     _call_count(0), _float_count(0), _double_count(0),
2813     _java_call_count(0), _inner_loop_count(0) { }
2814 
2815   void inc_call_count  () { _call_count  ++; }
2816   void inc_float_count () { _float_count ++; }
2817   void inc_double_count() { _double_count++; }
2818   void inc_java_call_count() { _java_call_count++; }
2819   void inc_inner_loop_count() { _inner_loop_count++; }
2820 
2821   int  get_call_count  () const { return _call_count  ; }
2822   int  get_float_count () const { return _float_count ; }
2823   int  get_double_count() const { return _double_count; }
2824   int  get_java_call_count() const { return _java_call_count; }
2825   int  get_inner_loop_count() const { return _inner_loop_count; }
2826 };
2827 
2828 // Eliminate trivially redundant StoreCMs and accumulate their
2829 // precedence edges.
2830 void Compile::eliminate_redundant_card_marks(Node* n) {
2831   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2832   if (n->in(MemNode::Address)->outcnt() > 1) {
2833     // There are multiple users of the same address so it might be
2834     // possible to eliminate some of the StoreCMs
2835     Node* mem = n->in(MemNode::Memory);
2836     Node* adr = n->in(MemNode::Address);
2837     Node* val = n->in(MemNode::ValueIn);
2838     Node* prev = n;
2839     bool done = false;
2840     // Walk the chain of StoreCMs eliminating ones that match.  As
2841     // long as it's a chain of single users then the optimization is
2842     // safe.  Eliminating partially redundant StoreCMs would require
2843     // cloning copies down the other paths.
2844     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2845       if (adr == mem->in(MemNode::Address) &&
2846           val == mem->in(MemNode::ValueIn)) {
2847         // redundant StoreCM
2848         if (mem->req() > MemNode::OopStore) {
2849           // Hasn't been processed by this code yet.
2850           n->add_prec(mem->in(MemNode::OopStore));
2851         } else {
2852           // Already converted to precedence edge
2853           for (uint i = mem->req(); i < mem->len(); i++) {
2854             // Accumulate any precedence edges
2855             if (mem->in(i) != NULL) {
2856               n->add_prec(mem->in(i));
2857             }
2858           }
2859           // Everything above this point has been processed.
2860           done = true;
2861         }
2862         // Eliminate the previous StoreCM
2863         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2864         assert(mem->outcnt() == 0, "should be dead");
2865         mem->disconnect_inputs(this);
2866       } else {
2867         prev = mem;
2868       }
2869       mem = prev->in(MemNode::Memory);
2870     }
2871   }
2872 }
2873 
2874 //------------------------------final_graph_reshaping_impl----------------------
2875 // Implement items 1-5 from final_graph_reshaping below.
2876 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2877 
2878   if ( n->outcnt() == 0 ) return; // dead node
2879   uint nop = n->Opcode();
2880 
2881   // Check for 2-input instruction with "last use" on right input.
2882   // Swap to left input.  Implements item (2).
2883   if( n->req() == 3 &&          // two-input instruction
2884       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2885       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2886       n->in(2)->outcnt() == 1 &&// right use IS a last use
2887       !n->in(2)->is_Con() ) {   // right use is not a constant
2888     // Check for commutative opcode
2889     switch( nop ) {
2890     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2891     case Op_MaxI:  case Op_MaxL:  case Op_MaxF:  case Op_MaxD:
2892     case Op_MinI:  case Op_MinL:  case Op_MinF:  case Op_MinD:
2893     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2894     case Op_AndL:  case Op_XorL:  case Op_OrL:
2895     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2896       // Move "last use" input to left by swapping inputs
2897       n->swap_edges(1, 2);
2898       break;
2899     }
2900     default:
2901       break;
2902     }
2903   }
2904 
2905 #ifdef ASSERT
2906   if( n->is_Mem() ) {
2907     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2908     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2909             // oop will be recorded in oop map if load crosses safepoint
2910             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2911                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2912             "raw memory operations should have control edge");
2913   }
2914   if (n->is_MemBar()) {
2915     MemBarNode* mb = n->as_MemBar();
2916     if (mb->trailing_store() || mb->trailing_load_store()) {
2917       assert(mb->leading_membar()->trailing_membar() == mb, "bad membar pair");
2918       Node* mem = BarrierSet::barrier_set()->barrier_set_c2()->step_over_gc_barrier(mb->in(MemBarNode::Precedent));
2919       assert((mb->trailing_store() && mem->is_Store() && mem->as_Store()->is_release()) ||
2920              (mb->trailing_load_store() && mem->is_LoadStore()), "missing mem op");
2921     } else if (mb->leading()) {
2922       assert(mb->trailing_membar()->leading_membar() == mb, "bad membar pair");
2923     }
2924   }
2925 #endif
2926   // Count FPU ops and common calls, implements item (3)
2927   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->final_graph_reshaping(this, n, nop);
2928   if (!gc_handled) {
2929     final_graph_reshaping_main_switch(n, frc, nop);
2930   }
2931 
2932   // Collect CFG split points
2933   if (n->is_MultiBranch() && !n->is_RangeCheck()) {
2934     frc._tests.push(n);
2935   }
2936 }
2937 
2938 void Compile::final_graph_reshaping_main_switch(Node* n, Final_Reshape_Counts& frc, uint nop) {
2939   switch( nop ) {
2940   // Count all float operations that may use FPU
2941   case Op_AddF:
2942   case Op_SubF:
2943   case Op_MulF:
2944   case Op_DivF:
2945   case Op_NegF:
2946   case Op_ModF:
2947   case Op_ConvI2F:
2948   case Op_ConF:
2949   case Op_CmpF:
2950   case Op_CmpF3:
2951   case Op_StoreF:
2952   case Op_LoadF:
2953   // case Op_ConvL2F: // longs are split into 32-bit halves
2954     frc.inc_float_count();
2955     break;
2956 
2957   case Op_ConvF2D:
2958   case Op_ConvD2F:
2959     frc.inc_float_count();
2960     frc.inc_double_count();
2961     break;
2962 
2963   // Count all double operations that may use FPU
2964   case Op_AddD:
2965   case Op_SubD:
2966   case Op_MulD:
2967   case Op_DivD:
2968   case Op_NegD:
2969   case Op_ModD:
2970   case Op_ConvI2D:
2971   case Op_ConvD2I:
2972   // case Op_ConvL2D: // handled by leaf call
2973   // case Op_ConvD2L: // handled by leaf call
2974   case Op_ConD:
2975   case Op_CmpD:
2976   case Op_CmpD3:
2977   case Op_StoreD:
2978   case Op_LoadD:
2979   case Op_LoadD_unaligned:
2980     frc.inc_double_count();
2981     break;
2982   case Op_Opaque1:              // Remove Opaque Nodes before matching
2983   case Op_Opaque2:              // Remove Opaque Nodes before matching
2984   case Op_Opaque3:
2985     n->subsume_by(n->in(1), this);
2986     break;
2987   case Op_CallStaticJava:
2988   case Op_CallJava:
2989   case Op_CallDynamicJava:
2990     frc.inc_java_call_count(); // Count java call site;
2991   case Op_CallRuntime:
2992   case Op_CallLeaf:
2993   case Op_CallLeafVector:
2994   case Op_CallNative:
2995   case Op_CallLeafNoFP: {
2996     assert (n->is_Call(), "");
2997     CallNode *call = n->as_Call();
2998     // Count call sites where the FP mode bit would have to be flipped.
2999     // Do not count uncommon runtime calls:
3000     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
3001     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
3002     if (!call->is_CallStaticJava() || !call->as_CallStaticJava()->_name) {
3003       frc.inc_call_count();   // Count the call site
3004     } else {                  // See if uncommon argument is shared
3005       Node *n = call->in(TypeFunc::Parms);
3006       int nop = n->Opcode();
3007       // Clone shared simple arguments to uncommon calls, item (1).
3008       if (n->outcnt() > 1 &&
3009           !n->is_Proj() &&
3010           nop != Op_CreateEx &&
3011           nop != Op_CheckCastPP &&
3012           nop != Op_DecodeN &&
3013           nop != Op_DecodeNKlass &&
3014           !n->is_Mem() &&
3015           !n->is_Phi()) {
3016         Node *x = n->clone();
3017         call->set_req(TypeFunc::Parms, x);
3018       }
3019     }
3020     break;
3021   }
3022 
3023   case Op_StoreCM:
3024     {
3025       // Convert OopStore dependence into precedence edge
3026       Node* prec = n->in(MemNode::OopStore);
3027       n->del_req(MemNode::OopStore);
3028       n->add_prec(prec);
3029       eliminate_redundant_card_marks(n);
3030     }
3031 
3032     // fall through
3033 
3034   case Op_StoreB:
3035   case Op_StoreC:
3036   case Op_StorePConditional:
3037   case Op_StoreI:
3038   case Op_StoreL:
3039   case Op_StoreIConditional:
3040   case Op_StoreLConditional:
3041   case Op_CompareAndSwapB:
3042   case Op_CompareAndSwapS:
3043   case Op_CompareAndSwapI:
3044   case Op_CompareAndSwapL:
3045   case Op_CompareAndSwapP:
3046   case Op_CompareAndSwapN:
3047   case Op_WeakCompareAndSwapB:
3048   case Op_WeakCompareAndSwapS:
3049   case Op_WeakCompareAndSwapI:
3050   case Op_WeakCompareAndSwapL:
3051   case Op_WeakCompareAndSwapP:
3052   case Op_WeakCompareAndSwapN:
3053   case Op_CompareAndExchangeB:
3054   case Op_CompareAndExchangeS:
3055   case Op_CompareAndExchangeI:
3056   case Op_CompareAndExchangeL:
3057   case Op_CompareAndExchangeP:
3058   case Op_CompareAndExchangeN:
3059   case Op_GetAndAddS:
3060   case Op_GetAndAddB:
3061   case Op_GetAndAddI:
3062   case Op_GetAndAddL:
3063   case Op_GetAndSetS:
3064   case Op_GetAndSetB:
3065   case Op_GetAndSetI:
3066   case Op_GetAndSetL:
3067   case Op_GetAndSetP:
3068   case Op_GetAndSetN:
3069   case Op_StoreP:
3070   case Op_StoreN:
3071   case Op_StoreNKlass:
3072   case Op_LoadB:
3073   case Op_LoadUB:
3074   case Op_LoadUS:
3075   case Op_LoadI:
3076   case Op_LoadKlass:
3077   case Op_LoadNKlass:
3078   case Op_LoadL:
3079   case Op_LoadL_unaligned:
3080   case Op_LoadPLocked:
3081   case Op_LoadP:
3082   case Op_LoadN:
3083   case Op_LoadRange:
3084   case Op_LoadS:
3085     break;
3086 
3087   case Op_AddP: {               // Assert sane base pointers
3088     Node *addp = n->in(AddPNode::Address);
3089     assert( !addp->is_AddP() ||
3090             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
3091             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
3092             "Base pointers must match (addp %u)", addp->_idx );
3093 #ifdef _LP64
3094     if ((UseCompressedOops || UseCompressedClassPointers) &&
3095         addp->Opcode() == Op_ConP &&
3096         addp == n->in(AddPNode::Base) &&
3097         n->in(AddPNode::Offset)->is_Con()) {
3098       // If the transformation of ConP to ConN+DecodeN is beneficial depends
3099       // on the platform and on the compressed oops mode.
3100       // Use addressing with narrow klass to load with offset on x86.
3101       // Some platforms can use the constant pool to load ConP.
3102       // Do this transformation here since IGVN will convert ConN back to ConP.
3103       const Type* t = addp->bottom_type();
3104       bool is_oop   = t->isa_oopptr() != NULL;
3105       bool is_klass = t->isa_klassptr() != NULL;
3106 
3107       if ((is_oop   && Matcher::const_oop_prefer_decode()  ) ||
3108           (is_klass && Matcher::const_klass_prefer_decode())) {
3109         Node* nn = NULL;
3110 
3111         int op = is_oop ? Op_ConN : Op_ConNKlass;
3112 
3113         // Look for existing ConN node of the same exact type.
3114         Node* r  = root();
3115         uint cnt = r->outcnt();
3116         for (uint i = 0; i < cnt; i++) {
3117           Node* m = r->raw_out(i);
3118           if (m!= NULL && m->Opcode() == op &&
3119               m->bottom_type()->make_ptr() == t) {
3120             nn = m;
3121             break;
3122           }
3123         }
3124         if (nn != NULL) {
3125           // Decode a narrow oop to match address
3126           // [R12 + narrow_oop_reg<<3 + offset]
3127           if (is_oop) {
3128             nn = new DecodeNNode(nn, t);
3129           } else {
3130             nn = new DecodeNKlassNode(nn, t);
3131           }
3132           // Check for succeeding AddP which uses the same Base.
3133           // Otherwise we will run into the assertion above when visiting that guy.
3134           for (uint i = 0; i < n->outcnt(); ++i) {
3135             Node *out_i = n->raw_out(i);
3136             if (out_i && out_i->is_AddP() && out_i->in(AddPNode::Base) == addp) {
3137               out_i->set_req(AddPNode::Base, nn);
3138 #ifdef ASSERT
3139               for (uint j = 0; j < out_i->outcnt(); ++j) {
3140                 Node *out_j = out_i->raw_out(j);
3141                 assert(out_j == NULL || !out_j->is_AddP() || out_j->in(AddPNode::Base) != addp,
3142                        "more than 2 AddP nodes in a chain (out_j %u)", out_j->_idx);
3143               }
3144 #endif
3145             }
3146           }
3147           n->set_req(AddPNode::Base, nn);
3148           n->set_req(AddPNode::Address, nn);
3149           if (addp->outcnt() == 0) {
3150             addp->disconnect_inputs(this);
3151           }
3152         }
3153       }
3154     }
3155 #endif
3156     break;
3157   }
3158 
3159   case Op_CastPP: {
3160     // Remove CastPP nodes to gain more freedom during scheduling but
3161     // keep the dependency they encode as control or precedence edges
3162     // (if control is set already) on memory operations. Some CastPP
3163     // nodes don't have a control (don't carry a dependency): skip
3164     // those.
3165     if (n->in(0) != NULL) {
3166       ResourceMark rm;
3167       Unique_Node_List wq;
3168       wq.push(n);
3169       for (uint next = 0; next < wq.size(); ++next) {
3170         Node *m = wq.at(next);
3171         for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
3172           Node* use = m->fast_out(i);
3173           if (use->is_Mem() || use->is_EncodeNarrowPtr()) {
3174             use->ensure_control_or_add_prec(n->in(0));
3175           } else {
3176             switch(use->Opcode()) {
3177             case Op_AddP:
3178             case Op_DecodeN:
3179             case Op_DecodeNKlass:
3180             case Op_CheckCastPP:
3181             case Op_CastPP:
3182               wq.push(use);
3183               break;
3184             }
3185           }
3186         }
3187       }
3188     }
3189     const bool is_LP64 = LP64_ONLY(true) NOT_LP64(false);
3190     if (is_LP64 && n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
3191       Node* in1 = n->in(1);
3192       const Type* t = n->bottom_type();
3193       Node* new_in1 = in1->clone();
3194       new_in1->as_DecodeN()->set_type(t);
3195 
3196       if (!Matcher::narrow_oop_use_complex_address()) {
3197         //
3198         // x86, ARM and friends can handle 2 adds in addressing mode
3199         // and Matcher can fold a DecodeN node into address by using
3200         // a narrow oop directly and do implicit NULL check in address:
3201         //
3202         // [R12 + narrow_oop_reg<<3 + offset]
3203         // NullCheck narrow_oop_reg
3204         //
3205         // On other platforms (Sparc) we have to keep new DecodeN node and
3206         // use it to do implicit NULL check in address:
3207         //
3208         // decode_not_null narrow_oop_reg, base_reg
3209         // [base_reg + offset]
3210         // NullCheck base_reg
3211         //
3212         // Pin the new DecodeN node to non-null path on these platform (Sparc)
3213         // to keep the information to which NULL check the new DecodeN node
3214         // corresponds to use it as value in implicit_null_check().
3215         //
3216         new_in1->set_req(0, n->in(0));
3217       }
3218 
3219       n->subsume_by(new_in1, this);
3220       if (in1->outcnt() == 0) {
3221         in1->disconnect_inputs(this);
3222       }
3223     } else {
3224       n->subsume_by(n->in(1), this);
3225       if (n->outcnt() == 0) {
3226         n->disconnect_inputs(this);
3227       }
3228     }
3229     break;
3230   }
3231 #ifdef _LP64
3232   case Op_CmpP:
3233     // Do this transformation here to preserve CmpPNode::sub() and
3234     // other TypePtr related Ideal optimizations (for example, ptr nullness).
3235     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
3236       Node* in1 = n->in(1);
3237       Node* in2 = n->in(2);
3238       if (!in1->is_DecodeNarrowPtr()) {
3239         in2 = in1;
3240         in1 = n->in(2);
3241       }
3242       assert(in1->is_DecodeNarrowPtr(), "sanity");
3243 
3244       Node* new_in2 = NULL;
3245       if (in2->is_DecodeNarrowPtr()) {
3246         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
3247         new_in2 = in2->in(1);
3248       } else if (in2->Opcode() == Op_ConP) {
3249         const Type* t = in2->bottom_type();
3250         if (t == TypePtr::NULL_PTR) {
3251           assert(in1->is_DecodeN(), "compare klass to null?");
3252           // Don't convert CmpP null check into CmpN if compressed
3253           // oops implicit null check is not generated.
3254           // This will allow to generate normal oop implicit null check.
3255           if (Matcher::gen_narrow_oop_implicit_null_checks())
3256             new_in2 = ConNode::make(TypeNarrowOop::NULL_PTR);
3257           //
3258           // This transformation together with CastPP transformation above
3259           // will generated code for implicit NULL checks for compressed oops.
3260           //
3261           // The original code after Optimize()
3262           //
3263           //    LoadN memory, narrow_oop_reg
3264           //    decode narrow_oop_reg, base_reg
3265           //    CmpP base_reg, NULL
3266           //    CastPP base_reg // NotNull
3267           //    Load [base_reg + offset], val_reg
3268           //
3269           // after these transformations will be
3270           //
3271           //    LoadN memory, narrow_oop_reg
3272           //    CmpN narrow_oop_reg, NULL
3273           //    decode_not_null narrow_oop_reg, base_reg
3274           //    Load [base_reg + offset], val_reg
3275           //
3276           // and the uncommon path (== NULL) will use narrow_oop_reg directly
3277           // since narrow oops can be used in debug info now (see the code in
3278           // final_graph_reshaping_walk()).
3279           //
3280           // At the end the code will be matched to
3281           // on x86:
3282           //
3283           //    Load_narrow_oop memory, narrow_oop_reg
3284           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
3285           //    NullCheck narrow_oop_reg
3286           //
3287           // and on sparc:
3288           //
3289           //    Load_narrow_oop memory, narrow_oop_reg
3290           //    decode_not_null narrow_oop_reg, base_reg
3291           //    Load [base_reg + offset], val_reg
3292           //    NullCheck base_reg
3293           //
3294         } else if (t->isa_oopptr()) {
3295           new_in2 = ConNode::make(t->make_narrowoop());
3296         } else if (t->isa_klassptr()) {
3297           new_in2 = ConNode::make(t->make_narrowklass());
3298         }
3299       }
3300       if (new_in2 != NULL) {
3301         Node* cmpN = new CmpNNode(in1->in(1), new_in2);
3302         n->subsume_by(cmpN, this);
3303         if (in1->outcnt() == 0) {
3304           in1->disconnect_inputs(this);
3305         }
3306         if (in2->outcnt() == 0) {
3307           in2->disconnect_inputs(this);
3308         }
3309       }
3310     }
3311     break;
3312 
3313   case Op_DecodeN:
3314   case Op_DecodeNKlass:
3315     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
3316     // DecodeN could be pinned when it can't be fold into
3317     // an address expression, see the code for Op_CastPP above.
3318     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
3319     break;
3320 
3321   case Op_EncodeP:
3322   case Op_EncodePKlass: {
3323     Node* in1 = n->in(1);
3324     if (in1->is_DecodeNarrowPtr()) {
3325       n->subsume_by(in1->in(1), this);
3326     } else if (in1->Opcode() == Op_ConP) {
3327       const Type* t = in1->bottom_type();
3328       if (t == TypePtr::NULL_PTR) {
3329         assert(t->isa_oopptr(), "null klass?");
3330         n->subsume_by(ConNode::make(TypeNarrowOop::NULL_PTR), this);
3331       } else if (t->isa_oopptr()) {
3332         n->subsume_by(ConNode::make(t->make_narrowoop()), this);
3333       } else if (t->isa_klassptr()) {
3334         n->subsume_by(ConNode::make(t->make_narrowklass()), this);
3335       }
3336     }
3337     if (in1->outcnt() == 0) {
3338       in1->disconnect_inputs(this);
3339     }
3340     break;
3341   }
3342 
3343   case Op_Proj: {
3344     if (OptimizeStringConcat || IncrementalInline) {
3345       ProjNode* proj = n->as_Proj();
3346       if (proj->_is_io_use) {
3347         assert(proj->_con == TypeFunc::I_O || proj->_con == TypeFunc::Memory, "");
3348         // Separate projections were used for the exception path which
3349         // are normally removed by a late inline.  If it wasn't inlined
3350         // then they will hang around and should just be replaced with
3351         // the original one. Merge them.
3352         Node* non_io_proj = proj->in(0)->as_Multi()->proj_out_or_null(proj->_con, false /*is_io_use*/);
3353         if (non_io_proj  != NULL) {
3354           proj->subsume_by(non_io_proj , this);
3355         }
3356       }
3357     }
3358     break;
3359   }
3360 
3361   case Op_Phi:
3362     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
3363       // The EncodeP optimization may create Phi with the same edges
3364       // for all paths. It is not handled well by Register Allocator.
3365       Node* unique_in = n->in(1);
3366       assert(unique_in != NULL, "");
3367       uint cnt = n->req();
3368       for (uint i = 2; i < cnt; i++) {
3369         Node* m = n->in(i);
3370         assert(m != NULL, "");
3371         if (unique_in != m)
3372           unique_in = NULL;
3373       }
3374       if (unique_in != NULL) {
3375         n->subsume_by(unique_in, this);
3376       }
3377     }
3378     break;
3379 
3380 #endif
3381 
3382 #ifdef ASSERT
3383   case Op_CastII:
3384     // Verify that all range check dependent CastII nodes were removed.
3385     if (n->isa_CastII()->has_range_check()) {
3386       n->dump(3);
3387       assert(false, "Range check dependent CastII node was not removed");
3388     }
3389     break;
3390 #endif
3391 
3392   case Op_ModI:
3393     if (UseDivMod) {
3394       // Check if a%b and a/b both exist
3395       Node* d = n->find_similar(Op_DivI);
3396       if (d) {
3397         // Replace them with a fused divmod if supported
3398         if (Matcher::has_match_rule(Op_DivModI)) {
3399           DivModINode* divmod = DivModINode::make(n);
3400           d->subsume_by(divmod->div_proj(), this);
3401           n->subsume_by(divmod->mod_proj(), this);
3402         } else {
3403           // replace a%b with a-((a/b)*b)
3404           Node* mult = new MulINode(d, d->in(2));
3405           Node* sub  = new SubINode(d->in(1), mult);
3406           n->subsume_by(sub, this);
3407         }
3408       }
3409     }
3410     break;
3411 
3412   case Op_ModL:
3413     if (UseDivMod) {
3414       // Check if a%b and a/b both exist
3415       Node* d = n->find_similar(Op_DivL);
3416       if (d) {
3417         // Replace them with a fused divmod if supported
3418         if (Matcher::has_match_rule(Op_DivModL)) {
3419           DivModLNode* divmod = DivModLNode::make(n);
3420           d->subsume_by(divmod->div_proj(), this);
3421           n->subsume_by(divmod->mod_proj(), this);
3422         } else {
3423           // replace a%b with a-((a/b)*b)
3424           Node* mult = new MulLNode(d, d->in(2));
3425           Node* sub  = new SubLNode(d->in(1), mult);
3426           n->subsume_by(sub, this);
3427         }
3428       }
3429     }
3430     break;
3431 
3432   case Op_LoadVector:
3433   case Op_StoreVector:
3434   case Op_LoadVectorGather:
3435   case Op_StoreVectorScatter:
3436   case Op_LoadVectorGatherMasked:
3437   case Op_StoreVectorScatterMasked:
3438   case Op_VectorCmpMasked:
3439   case Op_VectorMaskGen:
3440   case Op_LoadVectorMasked:
3441   case Op_StoreVectorMasked:
3442     break;
3443 
3444   case Op_AddReductionVI:
3445   case Op_AddReductionVL:
3446   case Op_AddReductionVF:
3447   case Op_AddReductionVD:
3448   case Op_MulReductionVI:
3449   case Op_MulReductionVL:
3450   case Op_MulReductionVF:
3451   case Op_MulReductionVD:
3452   case Op_MinReductionV:
3453   case Op_MaxReductionV:
3454   case Op_AndReductionV:
3455   case Op_OrReductionV:
3456   case Op_XorReductionV:
3457     break;
3458 
3459   case Op_PackB:
3460   case Op_PackS:
3461   case Op_PackI:
3462   case Op_PackF:
3463   case Op_PackL:
3464   case Op_PackD:
3465     if (n->req()-1 > 2) {
3466       // Replace many operand PackNodes with a binary tree for matching
3467       PackNode* p = (PackNode*) n;
3468       Node* btp = p->binary_tree_pack(1, n->req());
3469       n->subsume_by(btp, this);
3470     }
3471     break;
3472   case Op_Loop:
3473     assert(!n->as_Loop()->is_transformed_long_inner_loop() || _loop_opts_cnt == 0, "should have been turned into a counted loop");
3474   case Op_CountedLoop:
3475   case Op_LongCountedLoop:
3476   case Op_OuterStripMinedLoop:
3477     if (n->as_Loop()->is_inner_loop()) {
3478       frc.inc_inner_loop_count();
3479     }
3480     n->as_Loop()->verify_strip_mined(0);
3481     break;
3482   case Op_LShiftI:
3483   case Op_RShiftI:
3484   case Op_URShiftI:
3485   case Op_LShiftL:
3486   case Op_RShiftL:
3487   case Op_URShiftL:
3488     if (Matcher::need_masked_shift_count) {
3489       // The cpu's shift instructions don't restrict the count to the
3490       // lower 5/6 bits. We need to do the masking ourselves.
3491       Node* in2 = n->in(2);
3492       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3493       const TypeInt* t = in2->find_int_type();
3494       if (t != NULL && t->is_con()) {
3495         juint shift = t->get_con();
3496         if (shift > mask) { // Unsigned cmp
3497           n->set_req(2, ConNode::make(TypeInt::make(shift & mask)));
3498         }
3499       } else {
3500         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3501           Node* shift = new AndINode(in2, ConNode::make(TypeInt::make(mask)));
3502           n->set_req(2, shift);
3503         }
3504       }
3505       if (in2->outcnt() == 0) { // Remove dead node
3506         in2->disconnect_inputs(this);
3507       }
3508     }
3509     break;
3510   case Op_MemBarStoreStore:
3511   case Op_MemBarRelease:
3512     // Break the link with AllocateNode: it is no longer useful and
3513     // confuses register allocation.
3514     if (n->req() > MemBarNode::Precedent) {
3515       n->set_req(MemBarNode::Precedent, top());
3516     }
3517     break;
3518   case Op_MemBarAcquire: {
3519     if (n->as_MemBar()->trailing_load() && n->req() > MemBarNode::Precedent) {
3520       // At parse time, the trailing MemBarAcquire for a volatile load
3521       // is created with an edge to the load. After optimizations,
3522       // that input may be a chain of Phis. If those phis have no
3523       // other use, then the MemBarAcquire keeps them alive and
3524       // register allocation can be confused.
3525       ResourceMark rm;
3526       Unique_Node_List wq;
3527       wq.push(n->in(MemBarNode::Precedent));
3528       n->set_req(MemBarNode::Precedent, top());
3529       while (wq.size() > 0) {
3530         Node* m = wq.pop();
3531         if (m->outcnt() == 0) {
3532           for (uint j = 0; j < m->req(); j++) {
3533             Node* in = m->in(j);
3534             if (in != NULL) {
3535               wq.push(in);
3536             }
3537           }
3538           m->disconnect_inputs(this);
3539         }
3540       }
3541     }
3542     break;
3543   }
3544   case Op_Blackhole:
3545     break;
3546   case Op_RangeCheck: {
3547     RangeCheckNode* rc = n->as_RangeCheck();
3548     Node* iff = new IfNode(rc->in(0), rc->in(1), rc->_prob, rc->_fcnt);
3549     n->subsume_by(iff, this);
3550     frc._tests.push(iff);
3551     break;
3552   }
3553   case Op_ConvI2L: {
3554     if (!Matcher::convi2l_type_required) {
3555       // Code generation on some platforms doesn't need accurate
3556       // ConvI2L types. Widening the type can help remove redundant
3557       // address computations.
3558       n->as_Type()->set_type(TypeLong::INT);
3559       ResourceMark rm;
3560       Unique_Node_List wq;
3561       wq.push(n);
3562       for (uint next = 0; next < wq.size(); next++) {
3563         Node *m = wq.at(next);
3564 
3565         for(;;) {
3566           // Loop over all nodes with identical inputs edges as m
3567           Node* k = m->find_similar(m->Opcode());
3568           if (k == NULL) {
3569             break;
3570           }
3571           // Push their uses so we get a chance to remove node made
3572           // redundant
3573           for (DUIterator_Fast imax, i = k->fast_outs(imax); i < imax; i++) {
3574             Node* u = k->fast_out(i);
3575             if (u->Opcode() == Op_LShiftL ||
3576                 u->Opcode() == Op_AddL ||
3577                 u->Opcode() == Op_SubL ||
3578                 u->Opcode() == Op_AddP) {
3579               wq.push(u);
3580             }
3581           }
3582           // Replace all nodes with identical edges as m with m
3583           k->subsume_by(m, this);
3584         }
3585       }
3586     }
3587     break;
3588   }
3589   case Op_CmpUL: {
3590     if (!Matcher::has_match_rule(Op_CmpUL)) {
3591       // No support for unsigned long comparisons
3592       ConINode* sign_pos = new ConINode(TypeInt::make(BitsPerLong - 1));
3593       Node* sign_bit_mask = new RShiftLNode(n->in(1), sign_pos);
3594       Node* orl = new OrLNode(n->in(1), sign_bit_mask);
3595       ConLNode* remove_sign_mask = new ConLNode(TypeLong::make(max_jlong));
3596       Node* andl = new AndLNode(orl, remove_sign_mask);
3597       Node* cmp = new CmpLNode(andl, n->in(2));
3598       n->subsume_by(cmp, this);
3599     }
3600     break;
3601   }
3602   default:
3603     assert(!n->is_Call(), "");
3604     assert(!n->is_Mem(), "");
3605     assert(nop != Op_ProfileBoolean, "should be eliminated during IGVN");
3606     break;
3607   }
3608 }
3609 
3610 //------------------------------final_graph_reshaping_walk---------------------
3611 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3612 // requires that the walk visits a node's inputs before visiting the node.
3613 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3614   Unique_Node_List sfpt;
3615 
3616   frc._visited.set(root->_idx); // first, mark node as visited
3617   uint cnt = root->req();
3618   Node *n = root;
3619   uint  i = 0;
3620   while (true) {
3621     if (i < cnt) {
3622       // Place all non-visited non-null inputs onto stack
3623       Node* m = n->in(i);
3624       ++i;
3625       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3626         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3627           // compute worst case interpreter size in case of a deoptimization
3628           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3629 
3630           sfpt.push(m);
3631         }
3632         cnt = m->req();
3633         nstack.push(n, i); // put on stack parent and next input's index
3634         n = m;
3635         i = 0;
3636       }
3637     } else {
3638       // Now do post-visit work
3639       final_graph_reshaping_impl( n, frc );
3640       if (nstack.is_empty())
3641         break;             // finished
3642       n = nstack.node();   // Get node from stack
3643       cnt = n->req();
3644       i = nstack.index();
3645       nstack.pop();        // Shift to the next node on stack
3646     }
3647   }
3648 
3649   // Skip next transformation if compressed oops are not used.
3650   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3651       (!UseCompressedOops && !UseCompressedClassPointers))
3652     return;
3653 
3654   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3655   // It could be done for an uncommon traps or any safepoints/calls
3656   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3657   while (sfpt.size() > 0) {
3658     n = sfpt.pop();
3659     JVMState *jvms = n->as_SafePoint()->jvms();
3660     assert(jvms != NULL, "sanity");
3661     int start = jvms->debug_start();
3662     int end   = n->req();
3663     bool is_uncommon = (n->is_CallStaticJava() &&
3664                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3665     for (int j = start; j < end; j++) {
3666       Node* in = n->in(j);
3667       if (in->is_DecodeNarrowPtr()) {
3668         bool safe_to_skip = true;
3669         if (!is_uncommon ) {
3670           // Is it safe to skip?
3671           for (uint i = 0; i < in->outcnt(); i++) {
3672             Node* u = in->raw_out(i);
3673             if (!u->is_SafePoint() ||
3674                 (u->is_Call() && u->as_Call()->has_non_debug_use(n))) {
3675               safe_to_skip = false;
3676             }
3677           }
3678         }
3679         if (safe_to_skip) {
3680           n->set_req(j, in->in(1));
3681         }
3682         if (in->outcnt() == 0) {
3683           in->disconnect_inputs(this);
3684         }
3685       }
3686     }
3687   }
3688 }
3689 
3690 //------------------------------final_graph_reshaping--------------------------
3691 // Final Graph Reshaping.
3692 //
3693 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3694 //     and not commoned up and forced early.  Must come after regular
3695 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3696 //     inputs to Loop Phis; these will be split by the allocator anyways.
3697 //     Remove Opaque nodes.
3698 // (2) Move last-uses by commutative operations to the left input to encourage
3699 //     Intel update-in-place two-address operations and better register usage
3700 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3701 //     calls canonicalizing them back.
3702 // (3) Count the number of double-precision FP ops, single-precision FP ops
3703 //     and call sites.  On Intel, we can get correct rounding either by
3704 //     forcing singles to memory (requires extra stores and loads after each
3705 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3706 //     clearing the mode bit around call sites).  The mode bit is only used
3707 //     if the relative frequency of single FP ops to calls is low enough.
3708 //     This is a key transform for SPEC mpeg_audio.
3709 // (4) Detect infinite loops; blobs of code reachable from above but not
3710 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3711 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3712 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3713 //     Detection is by looking for IfNodes where only 1 projection is
3714 //     reachable from below or CatchNodes missing some targets.
3715 // (5) Assert for insane oop offsets in debug mode.
3716 
3717 bool Compile::final_graph_reshaping() {
3718   // an infinite loop may have been eliminated by the optimizer,
3719   // in which case the graph will be empty.
3720   if (root()->req() == 1) {
3721     record_method_not_compilable("trivial infinite loop");
3722     return true;
3723   }
3724 
3725   // Expensive nodes have their control input set to prevent the GVN
3726   // from freely commoning them. There's no GVN beyond this point so
3727   // no need to keep the control input. We want the expensive nodes to
3728   // be freely moved to the least frequent code path by gcm.
3729   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3730   for (int i = 0; i < expensive_count(); i++) {
3731     _expensive_nodes.at(i)->set_req(0, NULL);
3732   }
3733 
3734   Final_Reshape_Counts frc;
3735 
3736   // Visit everybody reachable!
3737   // Allocate stack of size C->live_nodes()/2 to avoid frequent realloc
3738   Node_Stack nstack(live_nodes() >> 1);
3739   final_graph_reshaping_walk(nstack, root(), frc);
3740 
3741   // Check for unreachable (from below) code (i.e., infinite loops).
3742   for( uint i = 0; i < frc._tests.size(); i++ ) {
3743     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3744     // Get number of CFG targets.
3745     // Note that PCTables include exception targets after calls.
3746     uint required_outcnt = n->required_outcnt();
3747     if (n->outcnt() != required_outcnt) {
3748       // Check for a few special cases.  Rethrow Nodes never take the
3749       // 'fall-thru' path, so expected kids is 1 less.
3750       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3751         if (n->in(0)->in(0)->is_Call()) {
3752           CallNode *call = n->in(0)->in(0)->as_Call();
3753           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3754             required_outcnt--;      // Rethrow always has 1 less kid
3755           } else if (call->req() > TypeFunc::Parms &&
3756                      call->is_CallDynamicJava()) {
3757             // Check for null receiver. In such case, the optimizer has
3758             // detected that the virtual call will always result in a null
3759             // pointer exception. The fall-through projection of this CatchNode
3760             // will not be populated.
3761             Node *arg0 = call->in(TypeFunc::Parms);
3762             if (arg0->is_Type() &&
3763                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3764               required_outcnt--;
3765             }
3766           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3767                      call->req() > TypeFunc::Parms+1 &&
3768                      call->is_CallStaticJava()) {
3769             // Check for negative array length. In such case, the optimizer has
3770             // detected that the allocation attempt will always result in an
3771             // exception. There is no fall-through projection of this CatchNode .
3772             Node *arg1 = call->in(TypeFunc::Parms+1);
3773             if (arg1->is_Type() &&
3774                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3775               required_outcnt--;
3776             }
3777           }
3778         }
3779       }
3780       // Recheck with a better notion of 'required_outcnt'
3781       if (n->outcnt() != required_outcnt) {
3782         record_method_not_compilable("malformed control flow");
3783         return true;            // Not all targets reachable!
3784       }
3785     }
3786     // Check that I actually visited all kids.  Unreached kids
3787     // must be infinite loops.
3788     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3789       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3790         record_method_not_compilable("infinite loop");
3791         return true;            // Found unvisited kid; must be unreach
3792       }
3793 
3794     // Here so verification code in final_graph_reshaping_walk()
3795     // always see an OuterStripMinedLoopEnd
3796     if (n->is_OuterStripMinedLoopEnd() || n->is_LongCountedLoopEnd()) {
3797       IfNode* init_iff = n->as_If();
3798       Node* iff = new IfNode(init_iff->in(0), init_iff->in(1), init_iff->_prob, init_iff->_fcnt);
3799       n->subsume_by(iff, this);
3800     }
3801   }
3802 
3803 #ifdef IA32
3804   // If original bytecodes contained a mixture of floats and doubles
3805   // check if the optimizer has made it homogenous, item (3).
3806   if (UseSSE == 0 &&
3807       frc.get_float_count() > 32 &&
3808       frc.get_double_count() == 0 &&
3809       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3810     set_24_bit_selection_and_mode(false, true);
3811   }
3812 #endif // IA32
3813 
3814   set_java_calls(frc.get_java_call_count());
3815   set_inner_loops(frc.get_inner_loop_count());
3816 
3817   // No infinite loops, no reason to bail out.
3818   return false;
3819 }
3820 
3821 //-----------------------------too_many_traps----------------------------------
3822 // Report if there are too many traps at the current method and bci.
3823 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3824 bool Compile::too_many_traps(ciMethod* method,
3825                              int bci,
3826                              Deoptimization::DeoptReason reason) {
3827   ciMethodData* md = method->method_data();
3828   if (md->is_empty()) {
3829     // Assume the trap has not occurred, or that it occurred only
3830     // because of a transient condition during start-up in the interpreter.
3831     return false;
3832   }
3833   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3834   if (md->has_trap_at(bci, m, reason) != 0) {
3835     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3836     // Also, if there are multiple reasons, or if there is no per-BCI record,
3837     // assume the worst.
3838     if (log())
3839       log()->elem("observe trap='%s' count='%d'",
3840                   Deoptimization::trap_reason_name(reason),
3841                   md->trap_count(reason));
3842     return true;
3843   } else {
3844     // Ignore method/bci and see if there have been too many globally.
3845     return too_many_traps(reason, md);
3846   }
3847 }
3848 
3849 // Less-accurate variant which does not require a method and bci.
3850 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3851                              ciMethodData* logmd) {
3852   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3853     // Too many traps globally.
3854     // Note that we use cumulative trap_count, not just md->trap_count.
3855     if (log()) {
3856       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3857       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3858                   Deoptimization::trap_reason_name(reason),
3859                   mcount, trap_count(reason));
3860     }
3861     return true;
3862   } else {
3863     // The coast is clear.
3864     return false;
3865   }
3866 }
3867 
3868 //--------------------------too_many_recompiles--------------------------------
3869 // Report if there are too many recompiles at the current method and bci.
3870 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3871 // Is not eager to return true, since this will cause the compiler to use
3872 // Action_none for a trap point, to avoid too many recompilations.
3873 bool Compile::too_many_recompiles(ciMethod* method,
3874                                   int bci,
3875                                   Deoptimization::DeoptReason reason) {
3876   ciMethodData* md = method->method_data();
3877   if (md->is_empty()) {
3878     // Assume the trap has not occurred, or that it occurred only
3879     // because of a transient condition during start-up in the interpreter.
3880     return false;
3881   }
3882   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3883   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3884   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3885   Deoptimization::DeoptReason per_bc_reason
3886     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3887   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3888   if ((per_bc_reason == Deoptimization::Reason_none
3889        || md->has_trap_at(bci, m, reason) != 0)
3890       // The trap frequency measure we care about is the recompile count:
3891       && md->trap_recompiled_at(bci, m)
3892       && md->overflow_recompile_count() >= bc_cutoff) {
3893     // Do not emit a trap here if it has already caused recompilations.
3894     // Also, if there are multiple reasons, or if there is no per-BCI record,
3895     // assume the worst.
3896     if (log())
3897       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3898                   Deoptimization::trap_reason_name(reason),
3899                   md->trap_count(reason),
3900                   md->overflow_recompile_count());
3901     return true;
3902   } else if (trap_count(reason) != 0
3903              && decompile_count() >= m_cutoff) {
3904     // Too many recompiles globally, and we have seen this sort of trap.
3905     // Use cumulative decompile_count, not just md->decompile_count.
3906     if (log())
3907       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3908                   Deoptimization::trap_reason_name(reason),
3909                   md->trap_count(reason), trap_count(reason),
3910                   md->decompile_count(), decompile_count());
3911     return true;
3912   } else {
3913     // The coast is clear.
3914     return false;
3915   }
3916 }
3917 
3918 // Compute when not to trap. Used by matching trap based nodes and
3919 // NullCheck optimization.
3920 void Compile::set_allowed_deopt_reasons() {
3921   _allowed_reasons = 0;
3922   if (is_method_compilation()) {
3923     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3924       assert(rs < BitsPerInt, "recode bit map");
3925       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3926         _allowed_reasons |= nth_bit(rs);
3927       }
3928     }
3929   }
3930 }
3931 
3932 bool Compile::needs_clinit_barrier(ciMethod* method, ciMethod* accessing_method) {
3933   return method->is_static() && needs_clinit_barrier(method->holder(), accessing_method);
3934 }
3935 
3936 bool Compile::needs_clinit_barrier(ciField* field, ciMethod* accessing_method) {
3937   return field->is_static() && needs_clinit_barrier(field->holder(), accessing_method);
3938 }
3939 
3940 bool Compile::needs_clinit_barrier(ciInstanceKlass* holder, ciMethod* accessing_method) {
3941   if (holder->is_initialized()) {
3942     return false;
3943   }
3944   if (holder->is_being_initialized()) {
3945     if (accessing_method->holder() == holder) {
3946       // Access inside a class. The barrier can be elided when access happens in <clinit>,
3947       // <init>, or a static method. In all those cases, there was an initialization
3948       // barrier on the holder klass passed.
3949       if (accessing_method->is_static_initializer() ||
3950           accessing_method->is_object_initializer() ||
3951           accessing_method->is_static()) {
3952         return false;
3953       }
3954     } else if (accessing_method->holder()->is_subclass_of(holder)) {
3955       // Access from a subclass. The barrier can be elided only when access happens in <clinit>.
3956       // In case of <init> or a static method, the barrier is on the subclass is not enough:
3957       // child class can become fully initialized while its parent class is still being initialized.
3958       if (accessing_method->is_static_initializer()) {
3959         return false;
3960       }
3961     }
3962     ciMethod* root = method(); // the root method of compilation
3963     if (root != accessing_method) {
3964       return needs_clinit_barrier(holder, root); // check access in the context of compilation root
3965     }
3966   }
3967   return true;
3968 }
3969 
3970 #ifndef PRODUCT
3971 //------------------------------verify_graph_edges---------------------------
3972 // Walk the Graph and verify that there is a one-to-one correspondence
3973 // between Use-Def edges and Def-Use edges in the graph.
3974 void Compile::verify_graph_edges(bool no_dead_code) {
3975   if (VerifyGraphEdges) {
3976     Unique_Node_List visited;
3977     // Call recursive graph walk to check edges
3978     _root->verify_edges(visited);
3979     if (no_dead_code) {
3980       // Now make sure that no visited node is used by an unvisited node.
3981       bool dead_nodes = false;
3982       Unique_Node_List checked;
3983       while (visited.size() > 0) {
3984         Node* n = visited.pop();
3985         checked.push(n);
3986         for (uint i = 0; i < n->outcnt(); i++) {
3987           Node* use = n->raw_out(i);
3988           if (checked.member(use))  continue;  // already checked
3989           if (visited.member(use))  continue;  // already in the graph
3990           if (use->is_Con())        continue;  // a dead ConNode is OK
3991           // At this point, we have found a dead node which is DU-reachable.
3992           if (!dead_nodes) {
3993             tty->print_cr("*** Dead nodes reachable via DU edges:");
3994             dead_nodes = true;
3995           }
3996           use->dump(2);
3997           tty->print_cr("---");
3998           checked.push(use);  // No repeats; pretend it is now checked.
3999         }
4000       }
4001       assert(!dead_nodes, "using nodes must be reachable from root");
4002     }
4003   }
4004 }
4005 #endif
4006 
4007 // The Compile object keeps track of failure reasons separately from the ciEnv.
4008 // This is required because there is not quite a 1-1 relation between the
4009 // ciEnv and its compilation task and the Compile object.  Note that one
4010 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
4011 // to backtrack and retry without subsuming loads.  Other than this backtracking
4012 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
4013 // by the logic in C2Compiler.
4014 void Compile::record_failure(const char* reason) {
4015   if (log() != NULL) {
4016     log()->elem("failure reason='%s' phase='compile'", reason);
4017   }
4018   if (_failure_reason == NULL) {
4019     // Record the first failure reason.
4020     _failure_reason = reason;
4021   }
4022 
4023   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
4024     C->print_method(PHASE_FAILURE);
4025   }
4026   _root = NULL;  // flush the graph, too
4027 }
4028 
4029 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator)
4030   : TraceTime(name, accumulator, CITime, CITimeVerbose),
4031     _phase_name(name), _dolog(CITimeVerbose)
4032 {
4033   if (_dolog) {
4034     C = Compile::current();
4035     _log = C->log();
4036   } else {
4037     C = NULL;
4038     _log = NULL;
4039   }
4040   if (_log != NULL) {
4041     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
4042     _log->stamp();
4043     _log->end_head();
4044   }
4045 }
4046 
4047 Compile::TracePhase::~TracePhase() {
4048 
4049   C = Compile::current();
4050   if (_dolog) {
4051     _log = C->log();
4052   } else {
4053     _log = NULL;
4054   }
4055 
4056 #ifdef ASSERT
4057   if (PrintIdealNodeCount) {
4058     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
4059                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
4060   }
4061 
4062   if (VerifyIdealNodeCount) {
4063     Compile::current()->print_missing_nodes();
4064   }
4065 #endif
4066 
4067   if (_log != NULL) {
4068     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
4069   }
4070 }
4071 
4072 //----------------------------static_subtype_check-----------------------------
4073 // Shortcut important common cases when superklass is exact:
4074 // (0) superklass is java.lang.Object (can occur in reflective code)
4075 // (1) subklass is already limited to a subtype of superklass => always ok
4076 // (2) subklass does not overlap with superklass => always fail
4077 // (3) superklass has NO subtypes and we can check with a simple compare.
4078 int Compile::static_subtype_check(ciKlass* superk, ciKlass* subk) {
4079   if (StressReflectiveCode) {
4080     return SSC_full_test;       // Let caller generate the general case.
4081   }
4082 
4083   if (superk == env()->Object_klass()) {
4084     return SSC_always_true;     // (0) this test cannot fail
4085   }
4086 
4087   ciType* superelem = superk;
4088   ciType* subelem = subk;
4089   if (superelem->is_array_klass()) {
4090     superelem = superelem->as_array_klass()->base_element_type();
4091   }
4092   if (subelem->is_array_klass()) {
4093     subelem = subelem->as_array_klass()->base_element_type();
4094   }
4095 
4096   if (!subk->is_interface()) {  // cannot trust static interface types yet
4097     if (subk->is_subtype_of(superk)) {
4098       return SSC_always_true;   // (1) false path dead; no dynamic test needed
4099     }
4100     if (!(superelem->is_klass() && superelem->as_klass()->is_interface()) &&
4101         !(subelem->is_klass() && subelem->as_klass()->is_interface()) &&
4102         !superk->is_subtype_of(subk)) {
4103       return SSC_always_false;  // (2) true path dead; no dynamic test needed
4104     }
4105   }
4106 
4107   // If casting to an instance klass, it must have no subtypes
4108   if (superk->is_interface()) {
4109     // Cannot trust interfaces yet.
4110     // %%% S.B. superk->nof_implementors() == 1
4111   } else if (superelem->is_instance_klass()) {
4112     ciInstanceKlass* ik = superelem->as_instance_klass();
4113     if (!ik->has_subklass() && !ik->is_interface()) {
4114       if (!ik->is_final()) {
4115         // Add a dependency if there is a chance of a later subclass.
4116         dependencies()->assert_leaf_type(ik);
4117       }
4118       return SSC_easy_test;     // (3) caller can do a simple ptr comparison
4119     }
4120   } else {
4121     // A primitive array type has no subtypes.
4122     return SSC_easy_test;       // (3) caller can do a simple ptr comparison
4123   }
4124 
4125   return SSC_full_test;
4126 }
4127 
4128 Node* Compile::conv_I2X_index(PhaseGVN* phase, Node* idx, const TypeInt* sizetype, Node* ctrl) {
4129 #ifdef _LP64
4130   // The scaled index operand to AddP must be a clean 64-bit value.
4131   // Java allows a 32-bit int to be incremented to a negative
4132   // value, which appears in a 64-bit register as a large
4133   // positive number.  Using that large positive number as an
4134   // operand in pointer arithmetic has bad consequences.
4135   // On the other hand, 32-bit overflow is rare, and the possibility
4136   // can often be excluded, if we annotate the ConvI2L node with
4137   // a type assertion that its value is known to be a small positive
4138   // number.  (The prior range check has ensured this.)
4139   // This assertion is used by ConvI2LNode::Ideal.
4140   int index_max = max_jint - 1;  // array size is max_jint, index is one less
4141   if (sizetype != NULL) index_max = sizetype->_hi - 1;
4142   const TypeInt* iidxtype = TypeInt::make(0, index_max, Type::WidenMax);
4143   idx = constrained_convI2L(phase, idx, iidxtype, ctrl);
4144 #endif
4145   return idx;
4146 }
4147 
4148 // Convert integer value to a narrowed long type dependent on ctrl (for example, a range check)
4149 Node* Compile::constrained_convI2L(PhaseGVN* phase, Node* value, const TypeInt* itype, Node* ctrl, bool carry_dependency) {
4150   if (ctrl != NULL) {
4151     // Express control dependency by a CastII node with a narrow type.
4152     value = new CastIINode(value, itype, carry_dependency ? ConstraintCastNode::StrongDependency : ConstraintCastNode::RegularDependency, true /* range check dependency */);
4153     // Make the CastII node dependent on the control input to prevent the narrowed ConvI2L
4154     // node from floating above the range check during loop optimizations. Otherwise, the
4155     // ConvI2L node may be eliminated independently of the range check, causing the data path
4156     // to become TOP while the control path is still there (although it's unreachable).
4157     value->set_req(0, ctrl);
4158     value = phase->transform(value);
4159   }
4160   const TypeLong* ltype = TypeLong::make(itype->_lo, itype->_hi, itype->_widen);
4161   return phase->transform(new ConvI2LNode(value, ltype));
4162 }
4163 
4164 void Compile::print_inlining_stream_free() {
4165   if (_print_inlining_stream != NULL) {
4166     _print_inlining_stream->~stringStream();
4167     _print_inlining_stream = NULL;
4168   }
4169 }
4170 
4171 // The message about the current inlining is accumulated in
4172 // _print_inlining_stream and transfered into the _print_inlining_list
4173 // once we know whether inlining succeeds or not. For regular
4174 // inlining, messages are appended to the buffer pointed by
4175 // _print_inlining_idx in the _print_inlining_list. For late inlining,
4176 // a new buffer is added after _print_inlining_idx in the list. This
4177 // way we can update the inlining message for late inlining call site
4178 // when the inlining is attempted again.
4179 void Compile::print_inlining_init() {
4180   if (print_inlining() || print_intrinsics()) {
4181     // print_inlining_init is actually called several times.
4182     print_inlining_stream_free();
4183     _print_inlining_stream = new stringStream();
4184     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer*>(comp_arena(), 1, 1, new PrintInliningBuffer());
4185   }
4186 }
4187 
4188 void Compile::print_inlining_reinit() {
4189   if (print_inlining() || print_intrinsics()) {
4190     print_inlining_stream_free();
4191     // Re allocate buffer when we change ResourceMark
4192     _print_inlining_stream = new stringStream();
4193   }
4194 }
4195 
4196 void Compile::print_inlining_reset() {
4197   _print_inlining_stream->reset();
4198 }
4199 
4200 void Compile::print_inlining_commit() {
4201   assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
4202   // Transfer the message from _print_inlining_stream to the current
4203   // _print_inlining_list buffer and clear _print_inlining_stream.
4204   _print_inlining_list->at(_print_inlining_idx)->ss()->write(_print_inlining_stream->base(), _print_inlining_stream->size());
4205   print_inlining_reset();
4206 }
4207 
4208 void Compile::print_inlining_push() {
4209   // Add new buffer to the _print_inlining_list at current position
4210   _print_inlining_idx++;
4211   _print_inlining_list->insert_before(_print_inlining_idx, new PrintInliningBuffer());
4212 }
4213 
4214 Compile::PrintInliningBuffer* Compile::print_inlining_current() {
4215   return _print_inlining_list->at(_print_inlining_idx);
4216 }
4217 
4218 void Compile::print_inlining_update(CallGenerator* cg) {
4219   if (print_inlining() || print_intrinsics()) {
4220     if (cg->is_late_inline()) {
4221       if (print_inlining_current()->cg() != cg &&
4222           (print_inlining_current()->cg() != NULL ||
4223            print_inlining_current()->ss()->size() != 0)) {
4224         print_inlining_push();
4225       }
4226       print_inlining_commit();
4227       print_inlining_current()->set_cg(cg);
4228     } else {
4229       if (print_inlining_current()->cg() != NULL) {
4230         print_inlining_push();
4231       }
4232       print_inlining_commit();
4233     }
4234   }
4235 }
4236 
4237 void Compile::print_inlining_move_to(CallGenerator* cg) {
4238   // We resume inlining at a late inlining call site. Locate the
4239   // corresponding inlining buffer so that we can update it.
4240   if (print_inlining() || print_intrinsics()) {
4241     for (int i = 0; i < _print_inlining_list->length(); i++) {
4242       if (_print_inlining_list->at(i)->cg() == cg) {
4243         _print_inlining_idx = i;
4244         return;
4245       }
4246     }
4247     ShouldNotReachHere();
4248   }
4249 }
4250 
4251 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
4252   if (print_inlining() || print_intrinsics()) {
4253     assert(_print_inlining_stream->size() > 0, "missing inlining msg");
4254     assert(print_inlining_current()->cg() == cg, "wrong entry");
4255     // replace message with new message
4256     _print_inlining_list->at_put(_print_inlining_idx, new PrintInliningBuffer());
4257     print_inlining_commit();
4258     print_inlining_current()->set_cg(cg);
4259   }
4260 }
4261 
4262 void Compile::print_inlining_assert_ready() {
4263   assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
4264 }
4265 
4266 void Compile::process_print_inlining() {
4267   assert(_late_inlines.length() == 0, "not drained yet");
4268   if (print_inlining() || print_intrinsics()) {
4269     ResourceMark rm;
4270     stringStream ss;
4271     assert(_print_inlining_list != NULL, "process_print_inlining should be called only once.");
4272     for (int i = 0; i < _print_inlining_list->length(); i++) {
4273       PrintInliningBuffer* pib = _print_inlining_list->at(i);
4274       ss.print("%s", pib->ss()->as_string());
4275       delete pib;
4276       DEBUG_ONLY(_print_inlining_list->at_put(i, NULL));
4277     }
4278     // Reset _print_inlining_list, it only contains destructed objects.
4279     // It is on the arena, so it will be freed when the arena is reset.
4280     _print_inlining_list = NULL;
4281     // _print_inlining_stream won't be used anymore, either.
4282     print_inlining_stream_free();
4283     size_t end = ss.size();
4284     _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
4285     strncpy(_print_inlining_output, ss.base(), end+1);
4286     _print_inlining_output[end] = 0;
4287   }
4288 }
4289 
4290 void Compile::dump_print_inlining() {
4291   if (_print_inlining_output != NULL) {
4292     tty->print_raw(_print_inlining_output);
4293   }
4294 }
4295 
4296 void Compile::log_late_inline(CallGenerator* cg) {
4297   if (log() != NULL) {
4298     log()->head("late_inline method='%d'  inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
4299                 cg->unique_id());
4300     JVMState* p = cg->call_node()->jvms();
4301     while (p != NULL) {
4302       log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
4303       p = p->caller();
4304     }
4305     log()->tail("late_inline");
4306   }
4307 }
4308 
4309 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
4310   log_late_inline(cg);
4311   if (log() != NULL) {
4312     log()->inline_fail(msg);
4313   }
4314 }
4315 
4316 void Compile::log_inline_id(CallGenerator* cg) {
4317   if (log() != NULL) {
4318     // The LogCompilation tool needs a unique way to identify late
4319     // inline call sites. This id must be unique for this call site in
4320     // this compilation. Try to have it unique across compilations as
4321     // well because it can be convenient when grepping through the log
4322     // file.
4323     // Distinguish OSR compilations from others in case CICountOSR is
4324     // on.
4325     jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
4326     cg->set_unique_id(id);
4327     log()->elem("inline_id id='" JLONG_FORMAT "'", id);
4328   }
4329 }
4330 
4331 void Compile::log_inline_failure(const char* msg) {
4332   if (C->log() != NULL) {
4333     C->log()->inline_fail(msg);
4334   }
4335 }
4336 
4337 
4338 // Dump inlining replay data to the stream.
4339 // Don't change thread state and acquire any locks.
4340 void Compile::dump_inline_data(outputStream* out) {
4341   InlineTree* inl_tree = ilt();
4342   if (inl_tree != NULL) {
4343     out->print(" inline %d", inl_tree->count());
4344     inl_tree->dump_replay_data(out);
4345   }
4346 }
4347 
4348 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
4349   if (n1->Opcode() < n2->Opcode())      return -1;
4350   else if (n1->Opcode() > n2->Opcode()) return 1;
4351 
4352   assert(n1->req() == n2->req(), "can't compare %s nodes: n1->req() = %d, n2->req() = %d", NodeClassNames[n1->Opcode()], n1->req(), n2->req());
4353   for (uint i = 1; i < n1->req(); i++) {
4354     if (n1->in(i) < n2->in(i))      return -1;
4355     else if (n1->in(i) > n2->in(i)) return 1;
4356   }
4357 
4358   return 0;
4359 }
4360 
4361 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
4362   Node* n1 = *n1p;
4363   Node* n2 = *n2p;
4364 
4365   return cmp_expensive_nodes(n1, n2);
4366 }
4367 
4368 void Compile::sort_expensive_nodes() {
4369   if (!expensive_nodes_sorted()) {
4370     _expensive_nodes.sort(cmp_expensive_nodes);
4371   }
4372 }
4373 
4374 bool Compile::expensive_nodes_sorted() const {
4375   for (int i = 1; i < _expensive_nodes.length(); i++) {
4376     if (cmp_expensive_nodes(_expensive_nodes.adr_at(i), _expensive_nodes.adr_at(i-1)) < 0) {
4377       return false;
4378     }
4379   }
4380   return true;
4381 }
4382 
4383 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
4384   if (_expensive_nodes.length() == 0) {
4385     return false;
4386   }
4387 
4388   assert(OptimizeExpensiveOps, "optimization off?");
4389 
4390   // Take this opportunity to remove dead nodes from the list
4391   int j = 0;
4392   for (int i = 0; i < _expensive_nodes.length(); i++) {
4393     Node* n = _expensive_nodes.at(i);
4394     if (!n->is_unreachable(igvn)) {
4395       assert(n->is_expensive(), "should be expensive");
4396       _expensive_nodes.at_put(j, n);
4397       j++;
4398     }
4399   }
4400   _expensive_nodes.trunc_to(j);
4401 
4402   // Then sort the list so that similar nodes are next to each other
4403   // and check for at least two nodes of identical kind with same data
4404   // inputs.
4405   sort_expensive_nodes();
4406 
4407   for (int i = 0; i < _expensive_nodes.length()-1; i++) {
4408     if (cmp_expensive_nodes(_expensive_nodes.adr_at(i), _expensive_nodes.adr_at(i+1)) == 0) {
4409       return true;
4410     }
4411   }
4412 
4413   return false;
4414 }
4415 
4416 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4417   if (_expensive_nodes.length() == 0) {
4418     return;
4419   }
4420 
4421   assert(OptimizeExpensiveOps, "optimization off?");
4422 
4423   // Sort to bring similar nodes next to each other and clear the
4424   // control input of nodes for which there's only a single copy.
4425   sort_expensive_nodes();
4426 
4427   int j = 0;
4428   int identical = 0;
4429   int i = 0;
4430   bool modified = false;
4431   for (; i < _expensive_nodes.length()-1; i++) {
4432     assert(j <= i, "can't write beyond current index");
4433     if (_expensive_nodes.at(i)->Opcode() == _expensive_nodes.at(i+1)->Opcode()) {
4434       identical++;
4435       _expensive_nodes.at_put(j++, _expensive_nodes.at(i));
4436       continue;
4437     }
4438     if (identical > 0) {
4439       _expensive_nodes.at_put(j++, _expensive_nodes.at(i));
4440       identical = 0;
4441     } else {
4442       Node* n = _expensive_nodes.at(i);
4443       igvn.replace_input_of(n, 0, NULL);
4444       igvn.hash_insert(n);
4445       modified = true;
4446     }
4447   }
4448   if (identical > 0) {
4449     _expensive_nodes.at_put(j++, _expensive_nodes.at(i));
4450   } else if (_expensive_nodes.length() >= 1) {
4451     Node* n = _expensive_nodes.at(i);
4452     igvn.replace_input_of(n, 0, NULL);
4453     igvn.hash_insert(n);
4454     modified = true;
4455   }
4456   _expensive_nodes.trunc_to(j);
4457   if (modified) {
4458     igvn.optimize();
4459   }
4460 }
4461 
4462 void Compile::add_expensive_node(Node * n) {
4463   assert(!_expensive_nodes.contains(n), "duplicate entry in expensive list");
4464   assert(n->is_expensive(), "expensive nodes with non-null control here only");
4465   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4466   if (OptimizeExpensiveOps) {
4467     _expensive_nodes.append(n);
4468   } else {
4469     // Clear control input and let IGVN optimize expensive nodes if
4470     // OptimizeExpensiveOps is off.
4471     n->set_req(0, NULL);
4472   }
4473 }
4474 
4475 /**
4476  * Track coarsened Lock and Unlock nodes.
4477  */
4478 
4479 class Lock_List : public Node_List {
4480   uint _origin_cnt;
4481 public:
4482   Lock_List(Arena *a, uint cnt) : Node_List(a), _origin_cnt(cnt) {}
4483   uint origin_cnt() const { return _origin_cnt; }
4484 };
4485 
4486 void Compile::add_coarsened_locks(GrowableArray<AbstractLockNode*>& locks) {
4487   int length = locks.length();
4488   if (length > 0) {
4489     // Have to keep this list until locks elimination during Macro nodes elimination.
4490     Lock_List* locks_list = new (comp_arena()) Lock_List(comp_arena(), length);
4491     for (int i = 0; i < length; i++) {
4492       AbstractLockNode* lock = locks.at(i);
4493       assert(lock->is_coarsened(), "expecting only coarsened AbstractLock nodes, but got '%s'[%d] node", lock->Name(), lock->_idx);
4494       locks_list->push(lock);
4495     }
4496     _coarsened_locks.append(locks_list);
4497   }
4498 }
4499 
4500 void Compile::remove_useless_coarsened_locks(Unique_Node_List& useful) {
4501   int count = coarsened_count();
4502   for (int i = 0; i < count; i++) {
4503     Node_List* locks_list = _coarsened_locks.at(i);
4504     for (uint j = 0; j < locks_list->size(); j++) {
4505       Node* lock = locks_list->at(j);
4506       assert(lock->is_AbstractLock(), "sanity");
4507       if (!useful.member(lock)) {
4508         locks_list->yank(lock);
4509       }
4510     }
4511   }
4512 }
4513 
4514 void Compile::remove_coarsened_lock(Node* n) {
4515   if (n->is_AbstractLock()) {
4516     int count = coarsened_count();
4517     for (int i = 0; i < count; i++) {
4518       Node_List* locks_list = _coarsened_locks.at(i);
4519       locks_list->yank(n);
4520     }
4521   }
4522 }
4523 
4524 bool Compile::coarsened_locks_consistent() {
4525   int count = coarsened_count();
4526   for (int i = 0; i < count; i++) {
4527     bool unbalanced = false;
4528     bool modified = false; // track locks kind modifications
4529     Lock_List* locks_list = (Lock_List*)_coarsened_locks.at(i);
4530     uint size = locks_list->size();
4531     if (size == 0) {
4532       unbalanced = false; // All locks were eliminated - good
4533     } else if (size != locks_list->origin_cnt()) {
4534       unbalanced = true; // Some locks were removed from list
4535     } else {
4536       for (uint j = 0; j < size; j++) {
4537         Node* lock = locks_list->at(j);
4538         // All nodes in group should have the same state (modified or not)
4539         if (!lock->as_AbstractLock()->is_coarsened()) {
4540           if (j == 0) {
4541             // first on list was modified, the rest should be too for consistency
4542             modified = true;
4543           } else if (!modified) {
4544             // this lock was modified but previous locks on the list were not
4545             unbalanced = true;
4546             break;
4547           }
4548         } else if (modified) {
4549           // previous locks on list were modified but not this lock
4550           unbalanced = true;
4551           break;
4552         }
4553       }
4554     }
4555     if (unbalanced) {
4556       // unbalanced monitor enter/exit - only some [un]lock nodes were removed or modified
4557 #ifdef ASSERT
4558       if (PrintEliminateLocks) {
4559         tty->print_cr("=== unbalanced coarsened locks ===");
4560         for (uint l = 0; l < size; l++) {
4561           locks_list->at(l)->dump();
4562         }
4563       }
4564 #endif
4565       record_failure(C2Compiler::retry_no_locks_coarsening());
4566       return false;
4567     }
4568   }
4569   return true;
4570 }
4571 
4572 /**
4573  * Remove the speculative part of types and clean up the graph
4574  */
4575 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4576   if (UseTypeSpeculation) {
4577     Unique_Node_List worklist;
4578     worklist.push(root());
4579     int modified = 0;
4580     // Go over all type nodes that carry a speculative type, drop the
4581     // speculative part of the type and enqueue the node for an igvn
4582     // which may optimize it out.
4583     for (uint next = 0; next < worklist.size(); ++next) {
4584       Node *n  = worklist.at(next);
4585       if (n->is_Type()) {
4586         TypeNode* tn = n->as_Type();
4587         const Type* t = tn->type();
4588         const Type* t_no_spec = t->remove_speculative();
4589         if (t_no_spec != t) {
4590           bool in_hash = igvn.hash_delete(n);
4591           assert(in_hash, "node should be in igvn hash table");
4592           tn->set_type(t_no_spec);
4593           igvn.hash_insert(n);
4594           igvn._worklist.push(n); // give it a chance to go away
4595           modified++;
4596         }
4597       }
4598       // Iterate over outs - endless loops is unreachable from below
4599       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4600         Node *m = n->fast_out(i);
4601         if (not_a_node(m)) {
4602           continue;
4603         }
4604         worklist.push(m);
4605       }
4606     }
4607     // Drop the speculative part of all types in the igvn's type table
4608     igvn.remove_speculative_types();
4609     if (modified > 0) {
4610       igvn.optimize();
4611     }
4612 #ifdef ASSERT
4613     // Verify that after the IGVN is over no speculative type has resurfaced
4614     worklist.clear();
4615     worklist.push(root());
4616     for (uint next = 0; next < worklist.size(); ++next) {
4617       Node *n  = worklist.at(next);
4618       const Type* t = igvn.type_or_null(n);
4619       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4620       if (n->is_Type()) {
4621         t = n->as_Type()->type();
4622         assert(t == t->remove_speculative(), "no more speculative types");
4623       }
4624       // Iterate over outs - endless loops is unreachable from below
4625       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4626         Node *m = n->fast_out(i);
4627         if (not_a_node(m)) {
4628           continue;
4629         }
4630         worklist.push(m);
4631       }
4632     }
4633     igvn.check_no_speculative_types();
4634 #endif
4635   }
4636 }
4637 
4638 // Auxiliary methods to support randomized stressing/fuzzing.
4639 
4640 int Compile::random() {
4641   _stress_seed = os::next_random(_stress_seed);
4642   return static_cast<int>(_stress_seed);
4643 }
4644 
4645 // This method can be called the arbitrary number of times, with current count
4646 // as the argument. The logic allows selecting a single candidate from the
4647 // running list of candidates as follows:
4648 //    int count = 0;
4649 //    Cand* selected = null;
4650 //    while(cand = cand->next()) {
4651 //      if (randomized_select(++count)) {
4652 //        selected = cand;
4653 //      }
4654 //    }
4655 //
4656 // Including count equalizes the chances any candidate is "selected".
4657 // This is useful when we don't have the complete list of candidates to choose
4658 // from uniformly. In this case, we need to adjust the randomicity of the
4659 // selection, or else we will end up biasing the selection towards the latter
4660 // candidates.
4661 //
4662 // Quick back-envelope calculation shows that for the list of n candidates
4663 // the equal probability for the candidate to persist as "best" can be
4664 // achieved by replacing it with "next" k-th candidate with the probability
4665 // of 1/k. It can be easily shown that by the end of the run, the
4666 // probability for any candidate is converged to 1/n, thus giving the
4667 // uniform distribution among all the candidates.
4668 //
4669 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4670 #define RANDOMIZED_DOMAIN_POW 29
4671 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4672 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4673 bool Compile::randomized_select(int count) {
4674   assert(count > 0, "only positive");
4675   return (random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4676 }
4677 
4678 CloneMap&     Compile::clone_map()                 { return _clone_map; }
4679 void          Compile::set_clone_map(Dict* d)      { _clone_map._dict = d; }
4680 
4681 void NodeCloneInfo::dump() const {
4682   tty->print(" {%d:%d} ", idx(), gen());
4683 }
4684 
4685 void CloneMap::clone(Node* old, Node* nnn, int gen) {
4686   uint64_t val = value(old->_idx);
4687   NodeCloneInfo cio(val);
4688   assert(val != 0, "old node should be in the map");
4689   NodeCloneInfo cin(cio.idx(), gen + cio.gen());
4690   insert(nnn->_idx, cin.get());
4691 #ifndef PRODUCT
4692   if (is_debug()) {
4693     tty->print_cr("CloneMap::clone inserted node %d info {%d:%d} into CloneMap", nnn->_idx, cin.idx(), cin.gen());
4694   }
4695 #endif
4696 }
4697 
4698 void CloneMap::verify_insert_and_clone(Node* old, Node* nnn, int gen) {
4699   NodeCloneInfo cio(value(old->_idx));
4700   if (cio.get() == 0) {
4701     cio.set(old->_idx, 0);
4702     insert(old->_idx, cio.get());
4703 #ifndef PRODUCT
4704     if (is_debug()) {
4705       tty->print_cr("CloneMap::verify_insert_and_clone inserted node %d info {%d:%d} into CloneMap", old->_idx, cio.idx(), cio.gen());
4706     }
4707 #endif
4708   }
4709   clone(old, nnn, gen);
4710 }
4711 
4712 int CloneMap::max_gen() const {
4713   int g = 0;
4714   DictI di(_dict);
4715   for(; di.test(); ++di) {
4716     int t = gen(di._key);
4717     if (g < t) {
4718       g = t;
4719 #ifndef PRODUCT
4720       if (is_debug()) {
4721         tty->print_cr("CloneMap::max_gen() update max=%d from %d", g, _2_node_idx_t(di._key));
4722       }
4723 #endif
4724     }
4725   }
4726   return g;
4727 }
4728 
4729 void CloneMap::dump(node_idx_t key) const {
4730   uint64_t val = value(key);
4731   if (val != 0) {
4732     NodeCloneInfo ni(val);
4733     ni.dump();
4734   }
4735 }
4736 
4737 // Move Allocate nodes to the start of the list
4738 void Compile::sort_macro_nodes() {
4739   int count = macro_count();
4740   int allocates = 0;
4741   for (int i = 0; i < count; i++) {
4742     Node* n = macro_node(i);
4743     if (n->is_Allocate()) {
4744       if (i != allocates) {
4745         Node* tmp = macro_node(allocates);
4746         _macro_nodes.at_put(allocates, n);
4747         _macro_nodes.at_put(i, tmp);
4748       }
4749       allocates++;
4750     }
4751   }
4752 }
4753 
4754 void Compile::print_method(CompilerPhaseType cpt, const char *name, int level) {
4755   EventCompilerPhase event;
4756   if (event.should_commit()) {
4757     CompilerEvent::PhaseEvent::post(event, C->_latest_stage_start_counter, cpt, C->_compile_id, level);
4758   }
4759 #ifndef PRODUCT
4760   if (should_print(level)) {
4761     _printer->print_method(name, level);
4762   }
4763 #endif
4764   C->_latest_stage_start_counter.stamp();
4765 }
4766 
4767 void Compile::print_method(CompilerPhaseType cpt, int level, int idx) {
4768   char output[1024];
4769 #ifndef PRODUCT
4770   if (idx != 0) {
4771     jio_snprintf(output, sizeof(output), "%s:%d", CompilerPhaseTypeHelper::to_string(cpt), idx);
4772   } else {
4773     jio_snprintf(output, sizeof(output), "%s", CompilerPhaseTypeHelper::to_string(cpt));
4774   }
4775 #endif
4776   print_method(cpt, output, level);
4777 }
4778 
4779 void Compile::print_method(CompilerPhaseType cpt, Node* n, int level) {
4780   ResourceMark rm;
4781   stringStream ss;
4782   ss.print_raw(CompilerPhaseTypeHelper::to_string(cpt));
4783   if (n != NULL) {
4784     ss.print(": %d %s ", n->_idx, NodeClassNames[n->Opcode()]);
4785   } else {
4786     ss.print_raw(": NULL");
4787   }
4788   C->print_method(cpt, ss.as_string(), level);
4789 }
4790 
4791 void Compile::end_method(int level) {
4792   EventCompilerPhase event;
4793   if (event.should_commit()) {
4794     CompilerEvent::PhaseEvent::post(event, C->_latest_stage_start_counter, PHASE_END, C->_compile_id, level);
4795   }
4796 
4797 #ifndef PRODUCT
4798   if (_method != NULL && should_print(level)) {
4799     _printer->end_method();
4800   }
4801 #endif
4802 }
4803 
4804 
4805 #ifndef PRODUCT
4806 IdealGraphPrinter* Compile::_debug_file_printer = NULL;
4807 IdealGraphPrinter* Compile::_debug_network_printer = NULL;
4808 
4809 // Called from debugger. Prints method to the default file with the default phase name.
4810 // This works regardless of any Ideal Graph Visualizer flags set or not.
4811 void igv_print() {
4812   Compile::current()->igv_print_method_to_file();
4813 }
4814 
4815 // Same as igv_print() above but with a specified phase name.
4816 void igv_print(const char* phase_name) {
4817   Compile::current()->igv_print_method_to_file(phase_name);
4818 }
4819 
4820 // Called from debugger. Prints method with the default phase name to the default network or the one specified with
4821 // the network flags for the Ideal Graph Visualizer, or to the default file depending on the 'network' argument.
4822 // This works regardless of any Ideal Graph Visualizer flags set or not.
4823 void igv_print(bool network) {
4824   if (network) {
4825     Compile::current()->igv_print_method_to_network();
4826   } else {
4827     Compile::current()->igv_print_method_to_file();
4828   }
4829 }
4830 
4831 // Same as igv_print(bool network) above but with a specified phase name.
4832 void igv_print(bool network, const char* phase_name) {
4833   if (network) {
4834     Compile::current()->igv_print_method_to_network(phase_name);
4835   } else {
4836     Compile::current()->igv_print_method_to_file(phase_name);
4837   }
4838 }
4839 
4840 // Called from debugger. Normal write to the default _printer. Only works if Ideal Graph Visualizer printing flags are set.
4841 void igv_print_default() {
4842   Compile::current()->print_method(PHASE_DEBUG, 0);
4843 }
4844 
4845 // Called from debugger, especially when replaying a trace in which the program state cannot be altered like with rr replay.
4846 // A method is appended to an existing default file with the default phase name. This means that igv_append() must follow
4847 // an earlier igv_print(*) call which sets up the file. This works regardless of any Ideal Graph Visualizer flags set or not.
4848 void igv_append() {
4849   Compile::current()->igv_print_method_to_file("Debug", true);
4850 }
4851 
4852 // Same as igv_append() above but with a specified phase name.
4853 void igv_append(const char* phase_name) {
4854   Compile::current()->igv_print_method_to_file(phase_name, true);
4855 }
4856 
4857 void Compile::igv_print_method_to_file(const char* phase_name, bool append) {
4858   const char* file_name = "custom_debug.xml";
4859   if (_debug_file_printer == NULL) {
4860     _debug_file_printer = new IdealGraphPrinter(C, file_name, append);
4861   } else {
4862     _debug_file_printer->update_compiled_method(C->method());
4863   }
4864   tty->print_cr("Method %s to %s", append ? "appended" : "printed", file_name);
4865   _debug_file_printer->print(phase_name, (Node*)C->root());
4866 }
4867 
4868 void Compile::igv_print_method_to_network(const char* phase_name) {
4869   if (_debug_network_printer == NULL) {
4870     _debug_network_printer = new IdealGraphPrinter(C);
4871   } else {
4872     _debug_network_printer->update_compiled_method(C->method());
4873   }
4874   tty->print_cr("Method printed over network stream to IGV");
4875   _debug_network_printer->print(phase_name, (Node*)C->root());
4876 }
4877 #endif
4878 
4879 void Compile::add_native_invoker(RuntimeStub* stub) {
4880   _native_invokers.append(stub);
4881 }
4882 
4883 Node* Compile::narrow_value(BasicType bt, Node* value, const Type* type, PhaseGVN* phase, bool transform_res) {
4884   if (type != NULL && phase->type(value)->higher_equal(type)) {
4885     return value;
4886   }
4887   Node* result = NULL;
4888   if (bt == T_BYTE) {
4889     result = phase->transform(new LShiftINode(value, phase->intcon(24)));
4890     result = new RShiftINode(result, phase->intcon(24));
4891   } else if (bt == T_BOOLEAN) {
4892     result = new AndINode(value, phase->intcon(0xFF));
4893   } else if (bt == T_CHAR) {
4894     result = new AndINode(value,phase->intcon(0xFFFF));
4895   } else {
4896     assert(bt == T_SHORT, "unexpected narrow type");
4897     result = phase->transform(new LShiftINode(value, phase->intcon(16)));
4898     result = new RShiftINode(result, phase->intcon(16));
4899   }
4900   if (transform_res) {
4901     result = phase->transform(result);
4902   }
4903   return result;
4904 }
4905