1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "asm/macroAssembler.hpp"
  27 #include "asm/macroAssembler.inline.hpp"
  28 #include "ci/ciReplay.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "code/exceptionHandlerTable.hpp"
  31 #include "code/nmethod.hpp"
  32 #include "compiler/compileBroker.hpp"
  33 #include "compiler/compileLog.hpp"
  34 #include "compiler/disassembler.hpp"
  35 #include "compiler/oopMap.hpp"
  36 #include "gc/shared/barrierSet.hpp"
  37 #include "gc/shared/c2/barrierSetC2.hpp"
  38 #include "memory/resourceArea.hpp"
  39 #include "opto/addnode.hpp"
  40 #include "opto/block.hpp"
  41 #include "opto/c2compiler.hpp"
  42 #include "opto/callGenerator.hpp"
  43 #include "opto/callnode.hpp"
  44 #include "opto/castnode.hpp"
  45 #include "opto/cfgnode.hpp"
  46 #include "opto/chaitin.hpp"
  47 #include "opto/compile.hpp"
  48 #include "opto/connode.hpp"
  49 #include "opto/convertnode.hpp"
  50 #include "opto/divnode.hpp"
  51 #include "opto/escape.hpp"
  52 #include "opto/idealGraphPrinter.hpp"
  53 #include "opto/loopnode.hpp"
  54 #include "opto/machnode.hpp"
  55 #include "opto/macro.hpp"
  56 #include "opto/matcher.hpp"
  57 #include "opto/mathexactnode.hpp"
  58 #include "opto/memnode.hpp"
  59 #include "opto/mulnode.hpp"
  60 #include "opto/narrowptrnode.hpp"
  61 #include "opto/node.hpp"
  62 #include "opto/opcodes.hpp"
  63 #include "opto/output.hpp"
  64 #include "opto/parse.hpp"
  65 #include "opto/phaseX.hpp"
  66 #include "opto/rootnode.hpp"
  67 #include "opto/runtime.hpp"
  68 #include "opto/stringopts.hpp"
  69 #include "opto/type.hpp"
  70 #include "opto/vectornode.hpp"
  71 #include "runtime/arguments.hpp"
  72 #include "runtime/sharedRuntime.hpp"
  73 #include "runtime/signature.hpp"
  74 #include "runtime/stubRoutines.hpp"
  75 #include "runtime/timer.hpp"
  76 #include "utilities/align.hpp"
  77 #include "utilities/copy.hpp"
  78 #include "utilities/macros.hpp"
  79 #if INCLUDE_G1GC
  80 #include "gc/g1/g1ThreadLocalData.hpp"
  81 #endif // INCLUDE_G1GC
  82 #if INCLUDE_ZGC
  83 #include "gc/z/c2/zBarrierSetC2.hpp"
  84 #endif
  85 
  86 
  87 // -------------------- Compile::mach_constant_base_node -----------------------
  88 // Constant table base node singleton.
  89 MachConstantBaseNode* Compile::mach_constant_base_node() {
  90   if (_mach_constant_base_node == NULL) {
  91     _mach_constant_base_node = new MachConstantBaseNode();
  92     _mach_constant_base_node->add_req(C->root());
  93   }
  94   return _mach_constant_base_node;
  95 }
  96 
  97 
  98 /// Support for intrinsics.
  99 
 100 // Return the index at which m must be inserted (or already exists).
 101 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 102 class IntrinsicDescPair {
 103  private:
 104   ciMethod* _m;
 105   bool _is_virtual;
 106  public:
 107   IntrinsicDescPair(ciMethod* m, bool is_virtual) : _m(m), _is_virtual(is_virtual) {}
 108   static int compare(IntrinsicDescPair* const& key, CallGenerator* const& elt) {
 109     ciMethod* m= elt->method();
 110     ciMethod* key_m = key->_m;
 111     if (key_m < m)      return -1;
 112     else if (key_m > m) return 1;
 113     else {
 114       bool is_virtual = elt->is_virtual();
 115       bool key_virtual = key->_is_virtual;
 116       if (key_virtual < is_virtual)      return -1;
 117       else if (key_virtual > is_virtual) return 1;
 118       else                               return 0;
 119     }
 120   }
 121 };
 122 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual, bool& found) {
 123 #ifdef ASSERT
 124   for (int i = 1; i < _intrinsics->length(); i++) {
 125     CallGenerator* cg1 = _intrinsics->at(i-1);
 126     CallGenerator* cg2 = _intrinsics->at(i);
 127     assert(cg1->method() != cg2->method()
 128            ? cg1->method()     < cg2->method()
 129            : cg1->is_virtual() < cg2->is_virtual(),
 130            "compiler intrinsics list must stay sorted");
 131   }
 132 #endif
 133   IntrinsicDescPair pair(m, is_virtual);
 134   return _intrinsics->find_sorted<IntrinsicDescPair*, IntrinsicDescPair::compare>(&pair, found);
 135 }
 136 
 137 void Compile::register_intrinsic(CallGenerator* cg) {
 138   if (_intrinsics == NULL) {
 139     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 140   }
 141   int len = _intrinsics->length();
 142   bool found = false;
 143   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual(), found);
 144   assert(!found, "registering twice");
 145   _intrinsics->insert_before(index, cg);
 146   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 147 }
 148 
 149 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 150   assert(m->is_loaded(), "don't try this on unloaded methods");
 151   if (_intrinsics != NULL) {
 152     bool found = false;
 153     int index = intrinsic_insertion_index(m, is_virtual, found);
 154      if (found) {
 155       return _intrinsics->at(index);
 156     }
 157   }
 158   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 159   if (m->intrinsic_id() != vmIntrinsics::_none &&
 160       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 161     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 162     if (cg != NULL) {
 163       // Save it for next time:
 164       register_intrinsic(cg);
 165       return cg;
 166     } else {
 167       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 168     }
 169   }
 170   return NULL;
 171 }
 172 
 173 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 174 // in library_call.cpp.
 175 
 176 
 177 #ifndef PRODUCT
 178 // statistics gathering...
 179 
 180 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 181 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 182 
 183 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 184   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 185   int oflags = _intrinsic_hist_flags[id];
 186   assert(flags != 0, "what happened?");
 187   if (is_virtual) {
 188     flags |= _intrinsic_virtual;
 189   }
 190   bool changed = (flags != oflags);
 191   if ((flags & _intrinsic_worked) != 0) {
 192     juint count = (_intrinsic_hist_count[id] += 1);
 193     if (count == 1) {
 194       changed = true;           // first time
 195     }
 196     // increment the overall count also:
 197     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 198   }
 199   if (changed) {
 200     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 201       // Something changed about the intrinsic's virtuality.
 202       if ((flags & _intrinsic_virtual) != 0) {
 203         // This is the first use of this intrinsic as a virtual call.
 204         if (oflags != 0) {
 205           // We already saw it as a non-virtual, so note both cases.
 206           flags |= _intrinsic_both;
 207         }
 208       } else if ((oflags & _intrinsic_both) == 0) {
 209         // This is the first use of this intrinsic as a non-virtual
 210         flags |= _intrinsic_both;
 211       }
 212     }
 213     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 214   }
 215   // update the overall flags also:
 216   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 217   return changed;
 218 }
 219 
 220 static char* format_flags(int flags, char* buf) {
 221   buf[0] = 0;
 222   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 223   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 224   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 225   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 226   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 227   if (buf[0] == 0)  strcat(buf, ",");
 228   assert(buf[0] == ',', "must be");
 229   return &buf[1];
 230 }
 231 
 232 void Compile::print_intrinsic_statistics() {
 233   char flagsbuf[100];
 234   ttyLocker ttyl;
 235   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 236   tty->print_cr("Compiler intrinsic usage:");
 237   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 238   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 239   #define PRINT_STAT_LINE(name, c, f) \
 240     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 241   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 242     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 243     int   flags = _intrinsic_hist_flags[id];
 244     juint count = _intrinsic_hist_count[id];
 245     if ((flags | count) != 0) {
 246       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 247     }
 248   }
 249   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 250   if (xtty != NULL)  xtty->tail("statistics");
 251 }
 252 
 253 void Compile::print_statistics() {
 254   { ttyLocker ttyl;
 255     if (xtty != NULL)  xtty->head("statistics type='opto'");
 256     Parse::print_statistics();
 257     PhaseCCP::print_statistics();
 258     PhaseRegAlloc::print_statistics();
 259     Scheduling::print_statistics();
 260     PhasePeephole::print_statistics();
 261     PhaseIdealLoop::print_statistics();
 262     if (xtty != NULL)  xtty->tail("statistics");
 263   }
 264   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 265     // put this under its own <statistics> element.
 266     print_intrinsic_statistics();
 267   }
 268 }
 269 #endif //PRODUCT
 270 
 271 // Support for bundling info
 272 Bundle* Compile::node_bundling(const Node *n) {
 273   assert(valid_bundle_info(n), "oob");
 274   return &_node_bundling_base[n->_idx];
 275 }
 276 
 277 bool Compile::valid_bundle_info(const Node *n) {
 278   return (_node_bundling_limit > n->_idx);
 279 }
 280 
 281 
 282 void Compile::gvn_replace_by(Node* n, Node* nn) {
 283   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 284     Node* use = n->last_out(i);
 285     bool is_in_table = initial_gvn()->hash_delete(use);
 286     uint uses_found = 0;
 287     for (uint j = 0; j < use->len(); j++) {
 288       if (use->in(j) == n) {
 289         if (j < use->req())
 290           use->set_req(j, nn);
 291         else
 292           use->set_prec(j, nn);
 293         uses_found++;
 294       }
 295     }
 296     if (is_in_table) {
 297       // reinsert into table
 298       initial_gvn()->hash_find_insert(use);
 299     }
 300     record_for_igvn(use);
 301     i -= uses_found;    // we deleted 1 or more copies of this edge
 302   }
 303 }
 304 
 305 
 306 static inline bool not_a_node(const Node* n) {
 307   if (n == NULL)                   return true;
 308   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 309   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 310   return false;
 311 }
 312 
 313 // Identify all nodes that are reachable from below, useful.
 314 // Use breadth-first pass that records state in a Unique_Node_List,
 315 // recursive traversal is slower.
 316 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 317   int estimated_worklist_size = live_nodes();
 318   useful.map( estimated_worklist_size, NULL );  // preallocate space
 319 
 320   // Initialize worklist
 321   if (root() != NULL)     { useful.push(root()); }
 322   // If 'top' is cached, declare it useful to preserve cached node
 323   if( cached_top_node() ) { useful.push(cached_top_node()); }
 324 
 325   // Push all useful nodes onto the list, breadthfirst
 326   for( uint next = 0; next < useful.size(); ++next ) {
 327     assert( next < unique(), "Unique useful nodes < total nodes");
 328     Node *n  = useful.at(next);
 329     uint max = n->len();
 330     for( uint i = 0; i < max; ++i ) {
 331       Node *m = n->in(i);
 332       if (not_a_node(m))  continue;
 333       useful.push(m);
 334     }
 335   }
 336 }
 337 
 338 // Update dead_node_list with any missing dead nodes using useful
 339 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 340 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 341   uint max_idx = unique();
 342   VectorSet& useful_node_set = useful.member_set();
 343 
 344   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 345     // If node with index node_idx is not in useful set,
 346     // mark it as dead in dead node list.
 347     if (! useful_node_set.test(node_idx) ) {
 348       record_dead_node(node_idx);
 349     }
 350   }
 351 }
 352 
 353 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 354   int shift = 0;
 355   for (int i = 0; i < inlines->length(); i++) {
 356     CallGenerator* cg = inlines->at(i);
 357     CallNode* call = cg->call_node();
 358     if (shift > 0) {
 359       inlines->at_put(i-shift, cg);
 360     }
 361     if (!useful.member(call)) {
 362       shift++;
 363     }
 364   }
 365   inlines->trunc_to(inlines->length()-shift);
 366 }
 367 
 368 // Disconnect all useless nodes by disconnecting those at the boundary.
 369 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 370   uint next = 0;
 371   while (next < useful.size()) {
 372     Node *n = useful.at(next++);
 373     if (n->is_SafePoint()) {
 374       // We're done with a parsing phase. Replaced nodes are not valid
 375       // beyond that point.
 376       n->as_SafePoint()->delete_replaced_nodes();
 377     }
 378     // Use raw traversal of out edges since this code removes out edges
 379     int max = n->outcnt();
 380     for (int j = 0; j < max; ++j) {
 381       Node* child = n->raw_out(j);
 382       if (! useful.member(child)) {
 383         assert(!child->is_top() || child != top(),
 384                "If top is cached in Compile object it is in useful list");
 385         // Only need to remove this out-edge to the useless node
 386         n->raw_del_out(j);
 387         --j;
 388         --max;
 389       }
 390     }
 391     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 392       record_for_igvn(n->unique_out());
 393     }
 394   }
 395   // Remove useless macro and predicate opaq nodes
 396   for (int i = C->macro_count()-1; i >= 0; i--) {
 397     Node* n = C->macro_node(i);
 398     if (!useful.member(n)) {
 399       remove_macro_node(n);
 400     }
 401   }
 402   // Remove useless CastII nodes with range check dependency
 403   for (int i = range_check_cast_count() - 1; i >= 0; i--) {
 404     Node* cast = range_check_cast_node(i);
 405     if (!useful.member(cast)) {
 406       remove_range_check_cast(cast);
 407     }
 408   }
 409   // Remove useless expensive nodes
 410   for (int i = C->expensive_count()-1; i >= 0; i--) {
 411     Node* n = C->expensive_node(i);
 412     if (!useful.member(n)) {
 413       remove_expensive_node(n);
 414     }
 415   }
 416   // Remove useless Opaque4 nodes
 417   for (int i = opaque4_count() - 1; i >= 0; i--) {
 418     Node* opaq = opaque4_node(i);
 419     if (!useful.member(opaq)) {
 420       remove_opaque4_node(opaq);
 421     }
 422   }
 423   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 424   bs->eliminate_useless_gc_barriers(useful);
 425   // clean up the late inline lists
 426   remove_useless_late_inlines(&_string_late_inlines, useful);
 427   remove_useless_late_inlines(&_boxing_late_inlines, useful);
 428   remove_useless_late_inlines(&_late_inlines, useful);
 429   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 430 }
 431 
 432 //------------------------------frame_size_in_words-----------------------------
 433 // frame_slots in units of words
 434 int Compile::frame_size_in_words() const {
 435   // shift is 0 in LP32 and 1 in LP64
 436   const int shift = (LogBytesPerWord - LogBytesPerInt);
 437   int words = _frame_slots >> shift;
 438   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 439   return words;
 440 }
 441 
 442 // To bang the stack of this compiled method we use the stack size
 443 // that the interpreter would need in case of a deoptimization. This
 444 // removes the need to bang the stack in the deoptimization blob which
 445 // in turn simplifies stack overflow handling.
 446 int Compile::bang_size_in_bytes() const {
 447   return MAX2(frame_size_in_bytes() + os::extra_bang_size_in_bytes(), _interpreter_frame_size);
 448 }
 449 
 450 // ============================================================================
 451 //------------------------------CompileWrapper---------------------------------
 452 class CompileWrapper : public StackObj {
 453   Compile *const _compile;
 454  public:
 455   CompileWrapper(Compile* compile);
 456 
 457   ~CompileWrapper();
 458 };
 459 
 460 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 461   // the Compile* pointer is stored in the current ciEnv:
 462   ciEnv* env = compile->env();
 463   assert(env == ciEnv::current(), "must already be a ciEnv active");
 464   assert(env->compiler_data() == NULL, "compile already active?");
 465   env->set_compiler_data(compile);
 466   assert(compile == Compile::current(), "sanity");
 467 
 468   compile->set_type_dict(NULL);
 469   compile->set_clone_map(new Dict(cmpkey, hashkey, _compile->comp_arena()));
 470   compile->clone_map().set_clone_idx(0);
 471   compile->set_type_hwm(NULL);
 472   compile->set_type_last_size(0);
 473   compile->set_last_tf(NULL, NULL);
 474   compile->set_indexSet_arena(NULL);
 475   compile->set_indexSet_free_block_list(NULL);
 476   compile->init_type_arena();
 477   Type::Initialize(compile);
 478   _compile->set_scratch_buffer_blob(NULL);
 479   _compile->begin_method();
 480   _compile->clone_map().set_debug(_compile->has_method() && _compile->directive()->CloneMapDebugOption);
 481 }
 482 CompileWrapper::~CompileWrapper() {
 483   _compile->end_method();
 484   if (_compile->scratch_buffer_blob() != NULL)
 485     BufferBlob::free(_compile->scratch_buffer_blob());
 486   _compile->env()->set_compiler_data(NULL);
 487 }
 488 
 489 
 490 //----------------------------print_compile_messages---------------------------
 491 void Compile::print_compile_messages() {
 492 #ifndef PRODUCT
 493   // Check if recompiling
 494   if (_subsume_loads == false && PrintOpto) {
 495     // Recompiling without allowing machine instructions to subsume loads
 496     tty->print_cr("*********************************************************");
 497     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 498     tty->print_cr("*********************************************************");
 499   }
 500   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 501     // Recompiling without escape analysis
 502     tty->print_cr("*********************************************************");
 503     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 504     tty->print_cr("*********************************************************");
 505   }
 506   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 507     // Recompiling without boxing elimination
 508     tty->print_cr("*********************************************************");
 509     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 510     tty->print_cr("*********************************************************");
 511   }
 512   if (C->directive()->BreakAtCompileOption) {
 513     // Open the debugger when compiling this method.
 514     tty->print("### Breaking when compiling: ");
 515     method()->print_short_name();
 516     tty->cr();
 517     BREAKPOINT;
 518   }
 519 
 520   if( PrintOpto ) {
 521     if (is_osr_compilation()) {
 522       tty->print("[OSR]%3d", _compile_id);
 523     } else {
 524       tty->print("%3d", _compile_id);
 525     }
 526   }
 527 #endif
 528 }
 529 
 530 
 531 //-----------------------init_scratch_buffer_blob------------------------------
 532 // Construct a temporary BufferBlob and cache it for this compile.
 533 void Compile::init_scratch_buffer_blob(int const_size) {
 534   // If there is already a scratch buffer blob allocated and the
 535   // constant section is big enough, use it.  Otherwise free the
 536   // current and allocate a new one.
 537   BufferBlob* blob = scratch_buffer_blob();
 538   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 539     // Use the current blob.
 540   } else {
 541     if (blob != NULL) {
 542       BufferBlob::free(blob);
 543     }
 544 
 545     ResourceMark rm;
 546     _scratch_const_size = const_size;
 547     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 548     blob = BufferBlob::create("Compile::scratch_buffer", size);
 549     // Record the buffer blob for next time.
 550     set_scratch_buffer_blob(blob);
 551     // Have we run out of code space?
 552     if (scratch_buffer_blob() == NULL) {
 553       // Let CompilerBroker disable further compilations.
 554       record_failure("Not enough space for scratch buffer in CodeCache");
 555       return;
 556     }
 557   }
 558 
 559   // Initialize the relocation buffers
 560   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 561   set_scratch_locs_memory(locs_buf);
 562 }
 563 
 564 
 565 //-----------------------scratch_emit_size-------------------------------------
 566 // Helper function that computes size by emitting code
 567 uint Compile::scratch_emit_size(const Node* n) {
 568   // Start scratch_emit_size section.
 569   set_in_scratch_emit_size(true);
 570 
 571   // Emit into a trash buffer and count bytes emitted.
 572   // This is a pretty expensive way to compute a size,
 573   // but it works well enough if seldom used.
 574   // All common fixed-size instructions are given a size
 575   // method by the AD file.
 576   // Note that the scratch buffer blob and locs memory are
 577   // allocated at the beginning of the compile task, and
 578   // may be shared by several calls to scratch_emit_size.
 579   // The allocation of the scratch buffer blob is particularly
 580   // expensive, since it has to grab the code cache lock.
 581   BufferBlob* blob = this->scratch_buffer_blob();
 582   assert(blob != NULL, "Initialize BufferBlob at start");
 583   assert(blob->size() > MAX_inst_size, "sanity");
 584   relocInfo* locs_buf = scratch_locs_memory();
 585   address blob_begin = blob->content_begin();
 586   address blob_end   = (address)locs_buf;
 587   assert(blob->contains(blob_end), "sanity");
 588   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 589   buf.initialize_consts_size(_scratch_const_size);
 590   buf.initialize_stubs_size(MAX_stubs_size);
 591   assert(locs_buf != NULL, "sanity");
 592   int lsize = MAX_locs_size / 3;
 593   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 594   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 595   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 596   // Mark as scratch buffer.
 597   buf.consts()->set_scratch_emit();
 598   buf.insts()->set_scratch_emit();
 599   buf.stubs()->set_scratch_emit();
 600 
 601   // Do the emission.
 602 
 603   Label fakeL; // Fake label for branch instructions.
 604   Label*   saveL = NULL;
 605   uint save_bnum = 0;
 606   bool is_branch = n->is_MachBranch();
 607   if (is_branch) {
 608     MacroAssembler masm(&buf);
 609     masm.bind(fakeL);
 610     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 611     n->as_MachBranch()->label_set(&fakeL, 0);
 612   }
 613   n->emit(buf, this->regalloc());
 614 
 615   // Emitting into the scratch buffer should not fail
 616   assert (!failing(), "Must not have pending failure. Reason is: %s", failure_reason());
 617 
 618   if (is_branch) // Restore label.
 619     n->as_MachBranch()->label_set(saveL, save_bnum);
 620 
 621   // End scratch_emit_size section.
 622   set_in_scratch_emit_size(false);
 623 
 624   return buf.insts_size();
 625 }
 626 
 627 
 628 // ============================================================================
 629 //------------------------------Compile standard-------------------------------
 630 debug_only( int Compile::_debug_idx = 100000; )
 631 
 632 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 633 // the continuation bci for on stack replacement.
 634 
 635 
 636 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 637                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing, DirectiveSet* directive)
 638                 : Phase(Compiler),
 639                   _env(ci_env),
 640                   _directive(directive),
 641                   _log(ci_env->log()),
 642                   _compile_id(ci_env->compile_id()),
 643                   _save_argument_registers(false),
 644                   _stub_name(NULL),
 645                   _stub_function(NULL),
 646                   _stub_entry_point(NULL),
 647                   _method(target),
 648                   _barrier_set_state(BarrierSet::barrier_set()->barrier_set_c2()->create_barrier_state(comp_arena())),
 649                   _entry_bci(osr_bci),
 650                   _initial_gvn(NULL),
 651                   _for_igvn(NULL),
 652                   _warm_calls(NULL),
 653                   _subsume_loads(subsume_loads),
 654                   _do_escape_analysis(do_escape_analysis),
 655                   _eliminate_boxing(eliminate_boxing),
 656                   _failure_reason(NULL),
 657                   _code_buffer("Compile::Fill_buffer"),
 658                   _orig_pc_slot(0),
 659                   _orig_pc_slot_offset_in_bytes(0),
 660                   _has_method_handle_invokes(false),
 661                   _mach_constant_base_node(NULL),
 662                   _node_bundling_limit(0),
 663                   _node_bundling_base(NULL),
 664                   _java_calls(0),
 665                   _inner_loops(0),
 666                   _scratch_const_size(-1),
 667                   _in_scratch_emit_size(false),
 668                   _dead_node_list(comp_arena()),
 669                   _dead_node_count(0),
 670 #ifndef PRODUCT
 671                   _trace_opto_output(directive->TraceOptoOutputOption),
 672                   _in_dump_cnt(0),
 673                   _printer(IdealGraphPrinter::printer()),
 674 #endif
 675                   _congraph(NULL),
 676                   _comp_arena(mtCompiler),
 677                   _node_arena(mtCompiler),
 678                   _old_arena(mtCompiler),
 679                   _Compile_types(mtCompiler),
 680                   _replay_inline_data(NULL),
 681                   _late_inlines(comp_arena(), 2, 0, NULL),
 682                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 683                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 684                   _late_inlines_pos(0),
 685                   _number_of_mh_late_inlines(0),
 686                   _inlining_progress(false),
 687                   _inlining_incrementally(false),
 688                   _print_inlining_list(NULL),
 689                   _print_inlining_stream(NULL),
 690                   _print_inlining_idx(0),
 691                   _print_inlining_output(NULL),
 692                   _interpreter_frame_size(0),
 693                   _max_node_limit(MaxNodeLimit),
 694                   _has_reserved_stack_access(target->has_reserved_stack_access()) {
 695   C = this;
 696 #ifndef PRODUCT
 697   if (_printer != NULL) {
 698     _printer->set_compile(this);
 699   }
 700 #endif
 701   CompileWrapper cw(this);
 702 
 703   if (CITimeVerbose) {
 704     tty->print(" ");
 705     target->holder()->name()->print();
 706     tty->print(".");
 707     target->print_short_name();
 708     tty->print("  ");
 709   }
 710   TraceTime t1("Total compilation time", &_t_totalCompilation, CITime, CITimeVerbose);
 711   TraceTime t2(NULL, &_t_methodCompilation, CITime, false);
 712 
 713 #ifndef PRODUCT
 714   bool print_opto_assembly = directive->PrintOptoAssemblyOption;
 715   if (!print_opto_assembly) {
 716     bool print_assembly = directive->PrintAssemblyOption;
 717     if (print_assembly && !Disassembler::can_decode()) {
 718       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 719       print_opto_assembly = true;
 720     }
 721   }
 722   set_print_assembly(print_opto_assembly);
 723   set_parsed_irreducible_loop(false);
 724 
 725   if (directive->ReplayInlineOption) {
 726     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 727   }
 728 #endif
 729   set_print_inlining(directive->PrintInliningOption || PrintOptoInlining);
 730   set_print_intrinsics(directive->PrintIntrinsicsOption);
 731   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 732 
 733   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 734     // Make sure the method being compiled gets its own MDO,
 735     // so we can at least track the decompile_count().
 736     // Need MDO to record RTM code generation state.
 737     method()->ensure_method_data();
 738   }
 739 
 740   Init(::AliasLevel);
 741 
 742 
 743   print_compile_messages();
 744 
 745   _ilt = InlineTree::build_inline_tree_root();
 746 
 747   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 748   assert(num_alias_types() >= AliasIdxRaw, "");
 749 
 750 #define MINIMUM_NODE_HASH  1023
 751   // Node list that Iterative GVN will start with
 752   Unique_Node_List for_igvn(comp_arena());
 753   set_for_igvn(&for_igvn);
 754 
 755   // GVN that will be run immediately on new nodes
 756   uint estimated_size = method()->code_size()*4+64;
 757   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 758   PhaseGVN gvn(node_arena(), estimated_size);
 759   set_initial_gvn(&gvn);
 760 
 761   print_inlining_init();
 762   { // Scope for timing the parser
 763     TracePhase tp("parse", &timers[_t_parser]);
 764 
 765     // Put top into the hash table ASAP.
 766     initial_gvn()->transform_no_reclaim(top());
 767 
 768     // Set up tf(), start(), and find a CallGenerator.
 769     CallGenerator* cg = NULL;
 770     if (is_osr_compilation()) {
 771       const TypeTuple *domain = StartOSRNode::osr_domain();
 772       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 773       init_tf(TypeFunc::make(domain, range));
 774       StartNode* s = new StartOSRNode(root(), domain);
 775       initial_gvn()->set_type_bottom(s);
 776       init_start(s);
 777       cg = CallGenerator::for_osr(method(), entry_bci());
 778     } else {
 779       // Normal case.
 780       init_tf(TypeFunc::make(method()));
 781       StartNode* s = new StartNode(root(), tf()->domain());
 782       initial_gvn()->set_type_bottom(s);
 783       init_start(s);
 784       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get) {
 785         // With java.lang.ref.reference.get() we must go through the
 786         // intrinsic - even when get() is the root
 787         // method of the compile - so that, if necessary, the value in
 788         // the referent field of the reference object gets recorded by
 789         // the pre-barrier code.
 790         cg = find_intrinsic(method(), false);
 791       }
 792       if (cg == NULL) {
 793         float past_uses = method()->interpreter_invocation_count();
 794         float expected_uses = past_uses;
 795         cg = CallGenerator::for_inline(method(), expected_uses);
 796       }
 797     }
 798     if (failing())  return;
 799     if (cg == NULL) {
 800       record_method_not_compilable("cannot parse method");
 801       return;
 802     }
 803     JVMState* jvms = build_start_state(start(), tf());
 804     if ((jvms = cg->generate(jvms)) == NULL) {
 805       if (!failure_reason_is(C2Compiler::retry_class_loading_during_parsing())) {
 806         record_method_not_compilable("method parse failed");
 807       }
 808       return;
 809     }
 810     GraphKit kit(jvms);
 811 
 812     if (!kit.stopped()) {
 813       // Accept return values, and transfer control we know not where.
 814       // This is done by a special, unique ReturnNode bound to root.
 815       return_values(kit.jvms());
 816     }
 817 
 818     if (kit.has_exceptions()) {
 819       // Any exceptions that escape from this call must be rethrown
 820       // to whatever caller is dynamically above us on the stack.
 821       // This is done by a special, unique RethrowNode bound to root.
 822       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 823     }
 824 
 825     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 826 
 827     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 828       inline_string_calls(true);
 829     }
 830 
 831     if (failing())  return;
 832 
 833     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 834 
 835     // Remove clutter produced by parsing.
 836     if (!failing()) {
 837       ResourceMark rm;
 838       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 839     }
 840   }
 841 
 842   // Note:  Large methods are capped off in do_one_bytecode().
 843   if (failing())  return;
 844 
 845   // After parsing, node notes are no longer automagic.
 846   // They must be propagated by register_new_node_with_optimizer(),
 847   // clone(), or the like.
 848   set_default_node_notes(NULL);
 849 
 850   for (;;) {
 851     int successes = Inline_Warm();
 852     if (failing())  return;
 853     if (successes == 0)  break;
 854   }
 855 
 856   // Drain the list.
 857   Finish_Warm();
 858 #ifndef PRODUCT
 859   if (_printer && _printer->should_print(1)) {
 860     _printer->print_inlining();
 861   }
 862 #endif
 863 
 864   if (failing())  return;
 865   NOT_PRODUCT( verify_graph_edges(); )
 866 
 867   // Now optimize
 868   Optimize();
 869   if (failing())  return;
 870   NOT_PRODUCT( verify_graph_edges(); )
 871 
 872 #ifndef PRODUCT
 873   if (PrintIdeal) {
 874     ttyLocker ttyl;  // keep the following output all in one block
 875     // This output goes directly to the tty, not the compiler log.
 876     // To enable tools to match it up with the compilation activity,
 877     // be sure to tag this tty output with the compile ID.
 878     if (xtty != NULL) {
 879       xtty->head("ideal compile_id='%d'%s", compile_id(),
 880                  is_osr_compilation()    ? " compile_kind='osr'" :
 881                  "");
 882     }
 883     root()->dump(9999);
 884     if (xtty != NULL) {
 885       xtty->tail("ideal");
 886     }
 887   }
 888 #endif
 889 
 890   NOT_PRODUCT( verify_barriers(); )
 891 
 892   // Dump compilation data to replay it.
 893   if (directive->DumpReplayOption) {
 894     env()->dump_replay_data(_compile_id);
 895   }
 896   if (directive->DumpInlineOption && (ilt() != NULL)) {
 897     env()->dump_inline_data(_compile_id);
 898   }
 899 
 900   // Now that we know the size of all the monitors we can add a fixed slot
 901   // for the original deopt pc.
 902 
 903   _orig_pc_slot =  fixed_slots();
 904   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 905   set_fixed_slots(next_slot);
 906 
 907   // Compute when to use implicit null checks. Used by matching trap based
 908   // nodes and NullCheck optimization.
 909   set_allowed_deopt_reasons();
 910 
 911   // Now generate code
 912   Code_Gen();
 913   if (failing())  return;
 914 
 915   // Check if we want to skip execution of all compiled code.
 916   {
 917 #ifndef PRODUCT
 918     if (OptoNoExecute) {
 919       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 920       return;
 921     }
 922 #endif
 923     TracePhase tp("install_code", &timers[_t_registerMethod]);
 924 
 925     if (is_osr_compilation()) {
 926       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 927       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 928     } else {
 929       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 930       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 931     }
 932 
 933     env()->register_method(_method, _entry_bci,
 934                            &_code_offsets,
 935                            _orig_pc_slot_offset_in_bytes,
 936                            code_buffer(),
 937                            frame_size_in_words(), _oop_map_set,
 938                            &_handler_table, &_inc_table,
 939                            compiler,
 940                            has_unsafe_access(),
 941                            SharedRuntime::is_wide_vector(max_vector_size()),
 942                            rtm_state()
 943                            );
 944 
 945     if (log() != NULL) // Print code cache state into compiler log
 946       log()->code_cache_state();
 947   }
 948 }
 949 
 950 //------------------------------Compile----------------------------------------
 951 // Compile a runtime stub
 952 Compile::Compile( ciEnv* ci_env,
 953                   TypeFunc_generator generator,
 954                   address stub_function,
 955                   const char *stub_name,
 956                   int is_fancy_jump,
 957                   bool pass_tls,
 958                   bool save_arg_registers,
 959                   bool return_pc,
 960                   DirectiveSet* directive)
 961   : Phase(Compiler),
 962     _env(ci_env),
 963     _directive(directive),
 964     _log(ci_env->log()),
 965     _compile_id(0),
 966     _save_argument_registers(save_arg_registers),
 967     _method(NULL),
 968     _stub_name(stub_name),
 969     _stub_function(stub_function),
 970     _stub_entry_point(NULL),
 971     _entry_bci(InvocationEntryBci),
 972     _initial_gvn(NULL),
 973     _for_igvn(NULL),
 974     _warm_calls(NULL),
 975     _orig_pc_slot(0),
 976     _orig_pc_slot_offset_in_bytes(0),
 977     _subsume_loads(true),
 978     _do_escape_analysis(false),
 979     _eliminate_boxing(false),
 980     _failure_reason(NULL),
 981     _code_buffer("Compile::Fill_buffer"),
 982     _has_method_handle_invokes(false),
 983     _mach_constant_base_node(NULL),
 984     _node_bundling_limit(0),
 985     _node_bundling_base(NULL),
 986     _java_calls(0),
 987     _inner_loops(0),
 988 #ifndef PRODUCT
 989     _trace_opto_output(directive->TraceOptoOutputOption),
 990     _in_dump_cnt(0),
 991     _printer(NULL),
 992 #endif
 993     _comp_arena(mtCompiler),
 994     _node_arena(mtCompiler),
 995     _old_arena(mtCompiler),
 996     _Compile_types(mtCompiler),
 997     _dead_node_list(comp_arena()),
 998     _dead_node_count(0),
 999     _congraph(NULL),
1000     _replay_inline_data(NULL),
1001     _number_of_mh_late_inlines(0),
1002     _inlining_progress(false),
1003     _inlining_incrementally(false),
1004     _print_inlining_list(NULL),
1005     _print_inlining_stream(NULL),
1006     _print_inlining_idx(0),
1007     _print_inlining_output(NULL),
1008     _allowed_reasons(0),
1009     _interpreter_frame_size(0),
1010     _max_node_limit(MaxNodeLimit),
1011     _has_reserved_stack_access(false) {
1012   C = this;
1013 
1014   TraceTime t1(NULL, &_t_totalCompilation, CITime, false);
1015   TraceTime t2(NULL, &_t_stubCompilation, CITime, false);
1016 
1017 #ifndef PRODUCT
1018   set_print_assembly(PrintFrameConverterAssembly);
1019   set_parsed_irreducible_loop(false);
1020 #endif
1021   set_has_irreducible_loop(false); // no loops
1022 
1023   CompileWrapper cw(this);
1024   Init(/*AliasLevel=*/ 0);
1025   init_tf((*generator)());
1026 
1027   {
1028     // The following is a dummy for the sake of GraphKit::gen_stub
1029     Unique_Node_List for_igvn(comp_arena());
1030     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
1031     PhaseGVN gvn(Thread::current()->resource_area(),255);
1032     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
1033     gvn.transform_no_reclaim(top());
1034 
1035     GraphKit kit;
1036     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1037   }
1038 
1039   NOT_PRODUCT( verify_graph_edges(); )
1040   Code_Gen();
1041   if (failing())  return;
1042 
1043 
1044   // Entry point will be accessed using compile->stub_entry_point();
1045   if (code_buffer() == NULL) {
1046     Matcher::soft_match_failure();
1047   } else {
1048     if (PrintAssembly && (WizardMode || Verbose))
1049       tty->print_cr("### Stub::%s", stub_name);
1050 
1051     if (!failing()) {
1052       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1053 
1054       // Make the NMethod
1055       // For now we mark the frame as never safe for profile stackwalking
1056       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1057                                                       code_buffer(),
1058                                                       CodeOffsets::frame_never_safe,
1059                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1060                                                       frame_size_in_words(),
1061                                                       _oop_map_set,
1062                                                       save_arg_registers);
1063       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1064 
1065       _stub_entry_point = rs->entry_point();
1066     }
1067   }
1068 }
1069 
1070 //------------------------------Init-------------------------------------------
1071 // Prepare for a single compilation
1072 void Compile::Init(int aliaslevel) {
1073   _unique  = 0;
1074   _regalloc = NULL;
1075 
1076   _tf      = NULL;  // filled in later
1077   _top     = NULL;  // cached later
1078   _matcher = NULL;  // filled in later
1079   _cfg     = NULL;  // filled in later
1080 
1081   set_24_bit_selection_and_mode(Use24BitFP, false);
1082 
1083   _node_note_array = NULL;
1084   _default_node_notes = NULL;
1085   DEBUG_ONLY( _modified_nodes = NULL; ) // Used in Optimize()
1086 
1087   _immutable_memory = NULL; // filled in at first inquiry
1088 
1089   // Globally visible Nodes
1090   // First set TOP to NULL to give safe behavior during creation of RootNode
1091   set_cached_top_node(NULL);
1092   set_root(new RootNode());
1093   // Now that you have a Root to point to, create the real TOP
1094   set_cached_top_node( new ConNode(Type::TOP) );
1095   set_recent_alloc(NULL, NULL);
1096 
1097   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1098   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1099   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1100   env()->set_dependencies(new Dependencies(env()));
1101 
1102   _fixed_slots = 0;
1103   set_has_split_ifs(false);
1104   set_has_loops(has_method() && method()->has_loops()); // first approximation
1105   set_has_stringbuilder(false);
1106   set_has_boxed_value(false);
1107   _trap_can_recompile = false;  // no traps emitted yet
1108   _major_progress = true; // start out assuming good things will happen
1109   set_has_unsafe_access(false);
1110   set_max_vector_size(0);
1111   set_clear_upper_avx(false);  //false as default for clear upper bits of ymm registers
1112   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1113   set_decompile_count(0);
1114 
1115   set_do_freq_based_layout(_directive->BlockLayoutByFrequencyOption);
1116   set_num_loop_opts(LoopOptsCount);
1117   set_do_inlining(Inline);
1118   set_max_inline_size(MaxInlineSize);
1119   set_freq_inline_size(FreqInlineSize);
1120   set_do_scheduling(OptoScheduling);
1121   set_do_count_invocations(false);
1122   set_do_method_data_update(false);
1123 
1124   set_do_vector_loop(false);
1125 
1126   if (AllowVectorizeOnDemand) {
1127     if (has_method() && (_directive->VectorizeOption || _directive->VectorizeDebugOption)) {
1128       set_do_vector_loop(true);
1129       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());})
1130     } else if (has_method() && method()->name() != 0 &&
1131                method()->intrinsic_id() == vmIntrinsics::_forEachRemaining) {
1132       set_do_vector_loop(true);
1133     }
1134   }
1135   set_use_cmove(UseCMoveUnconditionally /* || do_vector_loop()*/); //TODO: consider do_vector_loop() mandate use_cmove unconditionally
1136   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());})
1137 
1138   set_age_code(has_method() && method()->profile_aging());
1139   set_rtm_state(NoRTM); // No RTM lock eliding by default
1140   _max_node_limit = _directive->MaxNodeLimitOption;
1141 
1142 #if INCLUDE_RTM_OPT
1143   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1144     int rtm_state = method()->method_data()->rtm_state();
1145     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1146       // Don't generate RTM lock eliding code.
1147       set_rtm_state(NoRTM);
1148     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1149       // Generate RTM lock eliding code without abort ratio calculation code.
1150       set_rtm_state(UseRTM);
1151     } else if (UseRTMDeopt) {
1152       // Generate RTM lock eliding code and include abort ratio calculation
1153       // code if UseRTMDeopt is on.
1154       set_rtm_state(ProfileRTM);
1155     }
1156   }
1157 #endif
1158   if (debug_info()->recording_non_safepoints()) {
1159     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1160                         (comp_arena(), 8, 0, NULL));
1161     set_default_node_notes(Node_Notes::make(this));
1162   }
1163 
1164   // // -- Initialize types before each compile --
1165   // // Update cached type information
1166   // if( _method && _method->constants() )
1167   //   Type::update_loaded_types(_method, _method->constants());
1168 
1169   // Init alias_type map.
1170   if (!_do_escape_analysis && aliaslevel == 3)
1171     aliaslevel = 2;  // No unique types without escape analysis
1172   _AliasLevel = aliaslevel;
1173   const int grow_ats = 16;
1174   _max_alias_types = grow_ats;
1175   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1176   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1177   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1178   {
1179     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1180   }
1181   // Initialize the first few types.
1182   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1183   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1184   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1185   _num_alias_types = AliasIdxRaw+1;
1186   // Zero out the alias type cache.
1187   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1188   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1189   probe_alias_cache(NULL)->_index = AliasIdxTop;
1190 
1191   _intrinsics = NULL;
1192   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1193   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1194   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1195   _range_check_casts = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1196   _opaque4_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1197   register_library_intrinsics();
1198 }
1199 
1200 //---------------------------init_start----------------------------------------
1201 // Install the StartNode on this compile object.
1202 void Compile::init_start(StartNode* s) {
1203   if (failing())
1204     return; // already failing
1205   assert(s == start(), "");
1206 }
1207 
1208 /**
1209  * Return the 'StartNode'. We must not have a pending failure, since the ideal graph
1210  * can be in an inconsistent state, i.e., we can get segmentation faults when traversing
1211  * the ideal graph.
1212  */
1213 StartNode* Compile::start() const {
1214   assert (!failing(), "Must not have pending failure. Reason is: %s", failure_reason());
1215   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1216     Node* start = root()->fast_out(i);
1217     if (start->is_Start()) {
1218       return start->as_Start();
1219     }
1220   }
1221   fatal("Did not find Start node!");
1222   return NULL;
1223 }
1224 
1225 //-------------------------------immutable_memory-------------------------------------
1226 // Access immutable memory
1227 Node* Compile::immutable_memory() {
1228   if (_immutable_memory != NULL) {
1229     return _immutable_memory;
1230   }
1231   StartNode* s = start();
1232   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1233     Node *p = s->fast_out(i);
1234     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1235       _immutable_memory = p;
1236       return _immutable_memory;
1237     }
1238   }
1239   ShouldNotReachHere();
1240   return NULL;
1241 }
1242 
1243 //----------------------set_cached_top_node------------------------------------
1244 // Install the cached top node, and make sure Node::is_top works correctly.
1245 void Compile::set_cached_top_node(Node* tn) {
1246   if (tn != NULL)  verify_top(tn);
1247   Node* old_top = _top;
1248   _top = tn;
1249   // Calling Node::setup_is_top allows the nodes the chance to adjust
1250   // their _out arrays.
1251   if (_top != NULL)     _top->setup_is_top();
1252   if (old_top != NULL)  old_top->setup_is_top();
1253   assert(_top == NULL || top()->is_top(), "");
1254 }
1255 
1256 #ifdef ASSERT
1257 uint Compile::count_live_nodes_by_graph_walk() {
1258   Unique_Node_List useful(comp_arena());
1259   // Get useful node list by walking the graph.
1260   identify_useful_nodes(useful);
1261   return useful.size();
1262 }
1263 
1264 void Compile::print_missing_nodes() {
1265 
1266   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1267   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1268     return;
1269   }
1270 
1271   // This is an expensive function. It is executed only when the user
1272   // specifies VerifyIdealNodeCount option or otherwise knows the
1273   // additional work that needs to be done to identify reachable nodes
1274   // by walking the flow graph and find the missing ones using
1275   // _dead_node_list.
1276 
1277   Unique_Node_List useful(comp_arena());
1278   // Get useful node list by walking the graph.
1279   identify_useful_nodes(useful);
1280 
1281   uint l_nodes = C->live_nodes();
1282   uint l_nodes_by_walk = useful.size();
1283 
1284   if (l_nodes != l_nodes_by_walk) {
1285     if (_log != NULL) {
1286       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1287       _log->stamp();
1288       _log->end_head();
1289     }
1290     VectorSet& useful_member_set = useful.member_set();
1291     int last_idx = l_nodes_by_walk;
1292     for (int i = 0; i < last_idx; i++) {
1293       if (useful_member_set.test(i)) {
1294         if (_dead_node_list.test(i)) {
1295           if (_log != NULL) {
1296             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1297           }
1298           if (PrintIdealNodeCount) {
1299             // Print the log message to tty
1300               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1301               useful.at(i)->dump();
1302           }
1303         }
1304       }
1305       else if (! _dead_node_list.test(i)) {
1306         if (_log != NULL) {
1307           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1308         }
1309         if (PrintIdealNodeCount) {
1310           // Print the log message to tty
1311           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1312         }
1313       }
1314     }
1315     if (_log != NULL) {
1316       _log->tail("mismatched_nodes");
1317     }
1318   }
1319 }
1320 void Compile::record_modified_node(Node* n) {
1321   if (_modified_nodes != NULL && !_inlining_incrementally &&
1322       n->outcnt() != 0 && !n->is_Con()) {
1323     _modified_nodes->push(n);
1324   }
1325 }
1326 
1327 void Compile::remove_modified_node(Node* n) {
1328   if (_modified_nodes != NULL) {
1329     _modified_nodes->remove(n);
1330   }
1331 }
1332 #endif
1333 
1334 #ifndef PRODUCT
1335 void Compile::verify_top(Node* tn) const {
1336   if (tn != NULL) {
1337     assert(tn->is_Con(), "top node must be a constant");
1338     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1339     assert(tn->in(0) != NULL, "must have live top node");
1340   }
1341 }
1342 #endif
1343 
1344 
1345 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1346 
1347 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1348   guarantee(arr != NULL, "");
1349   int num_blocks = arr->length();
1350   if (grow_by < num_blocks)  grow_by = num_blocks;
1351   int num_notes = grow_by * _node_notes_block_size;
1352   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1353   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1354   while (num_notes > 0) {
1355     arr->append(notes);
1356     notes     += _node_notes_block_size;
1357     num_notes -= _node_notes_block_size;
1358   }
1359   assert(num_notes == 0, "exact multiple, please");
1360 }
1361 
1362 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1363   if (source == NULL || dest == NULL)  return false;
1364 
1365   if (dest->is_Con())
1366     return false;               // Do not push debug info onto constants.
1367 
1368 #ifdef ASSERT
1369   // Leave a bread crumb trail pointing to the original node:
1370   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1371     dest->set_debug_orig(source);
1372   }
1373 #endif
1374 
1375   if (node_note_array() == NULL)
1376     return false;               // Not collecting any notes now.
1377 
1378   // This is a copy onto a pre-existing node, which may already have notes.
1379   // If both nodes have notes, do not overwrite any pre-existing notes.
1380   Node_Notes* source_notes = node_notes_at(source->_idx);
1381   if (source_notes == NULL || source_notes->is_clear())  return false;
1382   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1383   if (dest_notes == NULL || dest_notes->is_clear()) {
1384     return set_node_notes_at(dest->_idx, source_notes);
1385   }
1386 
1387   Node_Notes merged_notes = (*source_notes);
1388   // The order of operations here ensures that dest notes will win...
1389   merged_notes.update_from(dest_notes);
1390   return set_node_notes_at(dest->_idx, &merged_notes);
1391 }
1392 
1393 
1394 //--------------------------allow_range_check_smearing-------------------------
1395 // Gating condition for coalescing similar range checks.
1396 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1397 // single covering check that is at least as strong as any of them.
1398 // If the optimization succeeds, the simplified (strengthened) range check
1399 // will always succeed.  If it fails, we will deopt, and then give up
1400 // on the optimization.
1401 bool Compile::allow_range_check_smearing() const {
1402   // If this method has already thrown a range-check,
1403   // assume it was because we already tried range smearing
1404   // and it failed.
1405   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1406   return !already_trapped;
1407 }
1408 
1409 
1410 //------------------------------flatten_alias_type-----------------------------
1411 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1412   int offset = tj->offset();
1413   TypePtr::PTR ptr = tj->ptr();
1414 
1415   // Known instance (scalarizable allocation) alias only with itself.
1416   bool is_known_inst = tj->isa_oopptr() != NULL &&
1417                        tj->is_oopptr()->is_known_instance();
1418 
1419   // Process weird unsafe references.
1420   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1421     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1422     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1423     tj = TypeOopPtr::BOTTOM;
1424     ptr = tj->ptr();
1425     offset = tj->offset();
1426   }
1427 
1428   // Array pointers need some flattening
1429   const TypeAryPtr *ta = tj->isa_aryptr();
1430   if (ta && ta->is_stable()) {
1431     // Erase stability property for alias analysis.
1432     tj = ta = ta->cast_to_stable(false);
1433   }
1434   if( ta && is_known_inst ) {
1435     if ( offset != Type::OffsetBot &&
1436          offset > arrayOopDesc::length_offset_in_bytes() ) {
1437       offset = Type::OffsetBot; // Flatten constant access into array body only
1438       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1439     }
1440   } else if( ta && _AliasLevel >= 2 ) {
1441     // For arrays indexed by constant indices, we flatten the alias
1442     // space to include all of the array body.  Only the header, klass
1443     // and array length can be accessed un-aliased.
1444     if( offset != Type::OffsetBot ) {
1445       if( ta->const_oop() ) { // MethodData* or Method*
1446         offset = Type::OffsetBot;   // Flatten constant access into array body
1447         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1448       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1449         // range is OK as-is.
1450         tj = ta = TypeAryPtr::RANGE;
1451       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1452         tj = TypeInstPtr::KLASS; // all klass loads look alike
1453         ta = TypeAryPtr::RANGE; // generic ignored junk
1454         ptr = TypePtr::BotPTR;
1455       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1456         tj = TypeInstPtr::MARK;
1457         ta = TypeAryPtr::RANGE; // generic ignored junk
1458         ptr = TypePtr::BotPTR;
1459       } else {                  // Random constant offset into array body
1460         offset = Type::OffsetBot;   // Flatten constant access into array body
1461         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1462       }
1463     }
1464     // Arrays of fixed size alias with arrays of unknown size.
1465     if (ta->size() != TypeInt::POS) {
1466       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1467       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1468     }
1469     // Arrays of known objects become arrays of unknown objects.
1470     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1471       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1472       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1473     }
1474     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1475       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1476       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1477     }
1478     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1479     // cannot be distinguished by bytecode alone.
1480     if (ta->elem() == TypeInt::BOOL) {
1481       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1482       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1483       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1484     }
1485     // During the 2nd round of IterGVN, NotNull castings are removed.
1486     // Make sure the Bottom and NotNull variants alias the same.
1487     // Also, make sure exact and non-exact variants alias the same.
1488     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1489       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1490     }
1491   }
1492 
1493   // Oop pointers need some flattening
1494   const TypeInstPtr *to = tj->isa_instptr();
1495   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1496     ciInstanceKlass *k = to->klass()->as_instance_klass();
1497     if( ptr == TypePtr::Constant ) {
1498       if (to->klass() != ciEnv::current()->Class_klass() ||
1499           offset < k->size_helper() * wordSize) {
1500         // No constant oop pointers (such as Strings); they alias with
1501         // unknown strings.
1502         assert(!is_known_inst, "not scalarizable allocation");
1503         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1504       }
1505     } else if( is_known_inst ) {
1506       tj = to; // Keep NotNull and klass_is_exact for instance type
1507     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1508       // During the 2nd round of IterGVN, NotNull castings are removed.
1509       // Make sure the Bottom and NotNull variants alias the same.
1510       // Also, make sure exact and non-exact variants alias the same.
1511       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1512     }
1513     if (to->speculative() != NULL) {
1514       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1515     }
1516     // Canonicalize the holder of this field
1517     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1518       // First handle header references such as a LoadKlassNode, even if the
1519       // object's klass is unloaded at compile time (4965979).
1520       if (!is_known_inst) { // Do it only for non-instance types
1521         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1522       }
1523     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1524       // Static fields are in the space above the normal instance
1525       // fields in the java.lang.Class instance.
1526       if (to->klass() != ciEnv::current()->Class_klass()) {
1527         to = NULL;
1528         tj = TypeOopPtr::BOTTOM;
1529         offset = tj->offset();
1530       }
1531     } else {
1532       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1533       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1534         if( is_known_inst ) {
1535           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1536         } else {
1537           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1538         }
1539       }
1540     }
1541   }
1542 
1543   // Klass pointers to object array klasses need some flattening
1544   const TypeKlassPtr *tk = tj->isa_klassptr();
1545   if( tk ) {
1546     // If we are referencing a field within a Klass, we need
1547     // to assume the worst case of an Object.  Both exact and
1548     // inexact types must flatten to the same alias class so
1549     // use NotNull as the PTR.
1550     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1551 
1552       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1553                                    TypeKlassPtr::OBJECT->klass(),
1554                                    offset);
1555     }
1556 
1557     ciKlass* klass = tk->klass();
1558     if( klass->is_obj_array_klass() ) {
1559       ciKlass* k = TypeAryPtr::OOPS->klass();
1560       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1561         k = TypeInstPtr::BOTTOM->klass();
1562       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1563     }
1564 
1565     // Check for precise loads from the primary supertype array and force them
1566     // to the supertype cache alias index.  Check for generic array loads from
1567     // the primary supertype array and also force them to the supertype cache
1568     // alias index.  Since the same load can reach both, we need to merge
1569     // these 2 disparate memories into the same alias class.  Since the
1570     // primary supertype array is read-only, there's no chance of confusion
1571     // where we bypass an array load and an array store.
1572     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1573     if (offset == Type::OffsetBot ||
1574         (offset >= primary_supers_offset &&
1575          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1576         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1577       offset = in_bytes(Klass::secondary_super_cache_offset());
1578       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1579     }
1580   }
1581 
1582   // Flatten all Raw pointers together.
1583   if (tj->base() == Type::RawPtr)
1584     tj = TypeRawPtr::BOTTOM;
1585 
1586   if (tj->base() == Type::AnyPtr)
1587     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1588 
1589   // Flatten all to bottom for now
1590   switch( _AliasLevel ) {
1591   case 0:
1592     tj = TypePtr::BOTTOM;
1593     break;
1594   case 1:                       // Flatten to: oop, static, field or array
1595     switch (tj->base()) {
1596     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1597     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1598     case Type::AryPtr:   // do not distinguish arrays at all
1599     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1600     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1601     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1602     default: ShouldNotReachHere();
1603     }
1604     break;
1605   case 2:                       // No collapsing at level 2; keep all splits
1606   case 3:                       // No collapsing at level 3; keep all splits
1607     break;
1608   default:
1609     Unimplemented();
1610   }
1611 
1612   offset = tj->offset();
1613   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1614 
1615   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1616           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1617           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1618           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1619           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1620           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1621           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1622           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1623   assert( tj->ptr() != TypePtr::TopPTR &&
1624           tj->ptr() != TypePtr::AnyNull &&
1625           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1626 //    assert( tj->ptr() != TypePtr::Constant ||
1627 //            tj->base() == Type::RawPtr ||
1628 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1629 
1630   return tj;
1631 }
1632 
1633 void Compile::AliasType::Init(int i, const TypePtr* at) {
1634   _index = i;
1635   _adr_type = at;
1636   _field = NULL;
1637   _element = NULL;
1638   _is_rewritable = true; // default
1639   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1640   if (atoop != NULL && atoop->is_known_instance()) {
1641     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1642     _general_index = Compile::current()->get_alias_index(gt);
1643   } else {
1644     _general_index = 0;
1645   }
1646 }
1647 
1648 BasicType Compile::AliasType::basic_type() const {
1649   if (element() != NULL) {
1650     const Type* element = adr_type()->is_aryptr()->elem();
1651     return element->isa_narrowoop() ? T_OBJECT : element->array_element_basic_type();
1652   } if (field() != NULL) {
1653     return field()->layout_type();
1654   } else {
1655     return T_ILLEGAL; // unknown
1656   }
1657 }
1658 
1659 //---------------------------------print_on------------------------------------
1660 #ifndef PRODUCT
1661 void Compile::AliasType::print_on(outputStream* st) {
1662   if (index() < 10)
1663         st->print("@ <%d> ", index());
1664   else  st->print("@ <%d>",  index());
1665   st->print(is_rewritable() ? "   " : " RO");
1666   int offset = adr_type()->offset();
1667   if (offset == Type::OffsetBot)
1668         st->print(" +any");
1669   else  st->print(" +%-3d", offset);
1670   st->print(" in ");
1671   adr_type()->dump_on(st);
1672   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1673   if (field() != NULL && tjp) {
1674     if (tjp->klass()  != field()->holder() ||
1675         tjp->offset() != field()->offset_in_bytes()) {
1676       st->print(" != ");
1677       field()->print();
1678       st->print(" ***");
1679     }
1680   }
1681 }
1682 
1683 void print_alias_types() {
1684   Compile* C = Compile::current();
1685   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1686   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1687     C->alias_type(idx)->print_on(tty);
1688     tty->cr();
1689   }
1690 }
1691 #endif
1692 
1693 
1694 //----------------------------probe_alias_cache--------------------------------
1695 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1696   intptr_t key = (intptr_t) adr_type;
1697   key ^= key >> logAliasCacheSize;
1698   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1699 }
1700 
1701 
1702 //-----------------------------grow_alias_types--------------------------------
1703 void Compile::grow_alias_types() {
1704   const int old_ats  = _max_alias_types; // how many before?
1705   const int new_ats  = old_ats;          // how many more?
1706   const int grow_ats = old_ats+new_ats;  // how many now?
1707   _max_alias_types = grow_ats;
1708   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1709   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1710   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1711   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1712 }
1713 
1714 
1715 //--------------------------------find_alias_type------------------------------
1716 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1717   if (_AliasLevel == 0)
1718     return alias_type(AliasIdxBot);
1719 
1720   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1721   if (ace->_adr_type == adr_type) {
1722     return alias_type(ace->_index);
1723   }
1724 
1725   // Handle special cases.
1726   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1727   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1728 
1729   // Do it the slow way.
1730   const TypePtr* flat = flatten_alias_type(adr_type);
1731 
1732 #ifdef ASSERT
1733   {
1734     ResourceMark rm;
1735     assert(flat == flatten_alias_type(flat), "not idempotent: adr_type = %s; flat = %s => %s",
1736            Type::str(adr_type), Type::str(flat), Type::str(flatten_alias_type(flat)));
1737     assert(flat != TypePtr::BOTTOM, "cannot alias-analyze an untyped ptr: adr_type = %s",
1738            Type::str(adr_type));
1739     if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1740       const TypeOopPtr* foop = flat->is_oopptr();
1741       // Scalarizable allocations have exact klass always.
1742       bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1743       const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1744       assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type: foop = %s; xoop = %s",
1745              Type::str(foop), Type::str(xoop));
1746     }
1747   }
1748 #endif
1749 
1750   int idx = AliasIdxTop;
1751   for (int i = 0; i < num_alias_types(); i++) {
1752     if (alias_type(i)->adr_type() == flat) {
1753       idx = i;
1754       break;
1755     }
1756   }
1757 
1758   if (idx == AliasIdxTop) {
1759     if (no_create)  return NULL;
1760     // Grow the array if necessary.
1761     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1762     // Add a new alias type.
1763     idx = _num_alias_types++;
1764     _alias_types[idx]->Init(idx, flat);
1765     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1766     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1767     if (flat->isa_instptr()) {
1768       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1769           && flat->is_instptr()->klass() == env()->Class_klass())
1770         alias_type(idx)->set_rewritable(false);
1771     }
1772     if (flat->isa_aryptr()) {
1773 #ifdef ASSERT
1774       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1775       // (T_BYTE has the weakest alignment and size restrictions...)
1776       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1777 #endif
1778       if (flat->offset() == TypePtr::OffsetBot) {
1779         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1780       }
1781     }
1782     if (flat->isa_klassptr()) {
1783       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1784         alias_type(idx)->set_rewritable(false);
1785       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1786         alias_type(idx)->set_rewritable(false);
1787       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1788         alias_type(idx)->set_rewritable(false);
1789       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1790         alias_type(idx)->set_rewritable(false);
1791     }
1792     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1793     // but the base pointer type is not distinctive enough to identify
1794     // references into JavaThread.)
1795 
1796     // Check for final fields.
1797     const TypeInstPtr* tinst = flat->isa_instptr();
1798     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1799       ciField* field;
1800       if (tinst->const_oop() != NULL &&
1801           tinst->klass() == ciEnv::current()->Class_klass() &&
1802           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1803         // static field
1804         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1805         field = k->get_field_by_offset(tinst->offset(), true);
1806       } else {
1807         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1808         field = k->get_field_by_offset(tinst->offset(), false);
1809       }
1810       assert(field == NULL ||
1811              original_field == NULL ||
1812              (field->holder() == original_field->holder() &&
1813               field->offset() == original_field->offset() &&
1814               field->is_static() == original_field->is_static()), "wrong field?");
1815       // Set field() and is_rewritable() attributes.
1816       if (field != NULL)  alias_type(idx)->set_field(field);
1817     }
1818   }
1819 
1820   // Fill the cache for next time.
1821   ace->_adr_type = adr_type;
1822   ace->_index    = idx;
1823   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1824 
1825   // Might as well try to fill the cache for the flattened version, too.
1826   AliasCacheEntry* face = probe_alias_cache(flat);
1827   if (face->_adr_type == NULL) {
1828     face->_adr_type = flat;
1829     face->_index    = idx;
1830     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1831   }
1832 
1833   return alias_type(idx);
1834 }
1835 
1836 
1837 Compile::AliasType* Compile::alias_type(ciField* field) {
1838   const TypeOopPtr* t;
1839   if (field->is_static())
1840     t = TypeInstPtr::make(field->holder()->java_mirror());
1841   else
1842     t = TypeOopPtr::make_from_klass_raw(field->holder());
1843   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1844   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1845   return atp;
1846 }
1847 
1848 
1849 //------------------------------have_alias_type--------------------------------
1850 bool Compile::have_alias_type(const TypePtr* adr_type) {
1851   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1852   if (ace->_adr_type == adr_type) {
1853     return true;
1854   }
1855 
1856   // Handle special cases.
1857   if (adr_type == NULL)             return true;
1858   if (adr_type == TypePtr::BOTTOM)  return true;
1859 
1860   return find_alias_type(adr_type, true, NULL) != NULL;
1861 }
1862 
1863 //-----------------------------must_alias--------------------------------------
1864 // True if all values of the given address type are in the given alias category.
1865 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1866   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1867   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1868   if (alias_idx == AliasIdxTop)         return false; // the empty category
1869   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1870 
1871   // the only remaining possible overlap is identity
1872   int adr_idx = get_alias_index(adr_type);
1873   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1874   assert(adr_idx == alias_idx ||
1875          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1876           && adr_type                       != TypeOopPtr::BOTTOM),
1877          "should not be testing for overlap with an unsafe pointer");
1878   return adr_idx == alias_idx;
1879 }
1880 
1881 //------------------------------can_alias--------------------------------------
1882 // True if any values of the given address type are in the given alias category.
1883 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1884   if (alias_idx == AliasIdxTop)         return false; // the empty category
1885   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1886   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1887   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1888 
1889   // the only remaining possible overlap is identity
1890   int adr_idx = get_alias_index(adr_type);
1891   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1892   return adr_idx == alias_idx;
1893 }
1894 
1895 
1896 
1897 //---------------------------pop_warm_call-------------------------------------
1898 WarmCallInfo* Compile::pop_warm_call() {
1899   WarmCallInfo* wci = _warm_calls;
1900   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1901   return wci;
1902 }
1903 
1904 //----------------------------Inline_Warm--------------------------------------
1905 int Compile::Inline_Warm() {
1906   // If there is room, try to inline some more warm call sites.
1907   // %%% Do a graph index compaction pass when we think we're out of space?
1908   if (!InlineWarmCalls)  return 0;
1909 
1910   int calls_made_hot = 0;
1911   int room_to_grow   = NodeCountInliningCutoff - unique();
1912   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1913   int amount_grown   = 0;
1914   WarmCallInfo* call;
1915   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1916     int est_size = (int)call->size();
1917     if (est_size > (room_to_grow - amount_grown)) {
1918       // This one won't fit anyway.  Get rid of it.
1919       call->make_cold();
1920       continue;
1921     }
1922     call->make_hot();
1923     calls_made_hot++;
1924     amount_grown   += est_size;
1925     amount_to_grow -= est_size;
1926   }
1927 
1928   if (calls_made_hot > 0)  set_major_progress();
1929   return calls_made_hot;
1930 }
1931 
1932 
1933 //----------------------------Finish_Warm--------------------------------------
1934 void Compile::Finish_Warm() {
1935   if (!InlineWarmCalls)  return;
1936   if (failing())  return;
1937   if (warm_calls() == NULL)  return;
1938 
1939   // Clean up loose ends, if we are out of space for inlining.
1940   WarmCallInfo* call;
1941   while ((call = pop_warm_call()) != NULL) {
1942     call->make_cold();
1943   }
1944 }
1945 
1946 //---------------------cleanup_loop_predicates-----------------------
1947 // Remove the opaque nodes that protect the predicates so that all unused
1948 // checks and uncommon_traps will be eliminated from the ideal graph
1949 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1950   if (predicate_count()==0) return;
1951   for (int i = predicate_count(); i > 0; i--) {
1952     Node * n = predicate_opaque1_node(i-1);
1953     assert(n->Opcode() == Op_Opaque1, "must be");
1954     igvn.replace_node(n, n->in(1));
1955   }
1956   assert(predicate_count()==0, "should be clean!");
1957 }
1958 
1959 void Compile::add_range_check_cast(Node* n) {
1960   assert(n->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1961   assert(!_range_check_casts->contains(n), "duplicate entry in range check casts");
1962   _range_check_casts->append(n);
1963 }
1964 
1965 // Remove all range check dependent CastIINodes.
1966 void Compile::remove_range_check_casts(PhaseIterGVN &igvn) {
1967   for (int i = range_check_cast_count(); i > 0; i--) {
1968     Node* cast = range_check_cast_node(i-1);
1969     assert(cast->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1970     igvn.replace_node(cast, cast->in(1));
1971   }
1972   assert(range_check_cast_count() == 0, "should be empty");
1973 }
1974 
1975 void Compile::add_opaque4_node(Node* n) {
1976   assert(n->Opcode() == Op_Opaque4, "Opaque4 only");
1977   assert(!_opaque4_nodes->contains(n), "duplicate entry in Opaque4 list");
1978   _opaque4_nodes->append(n);
1979 }
1980 
1981 // Remove all Opaque4 nodes.
1982 void Compile::remove_opaque4_nodes(PhaseIterGVN &igvn) {
1983   for (int i = opaque4_count(); i > 0; i--) {
1984     Node* opaq = opaque4_node(i-1);
1985     assert(opaq->Opcode() == Op_Opaque4, "Opaque4 only");
1986     igvn.replace_node(opaq, opaq->in(2));
1987   }
1988   assert(opaque4_count() == 0, "should be empty");
1989 }
1990 
1991 // StringOpts and late inlining of string methods
1992 void Compile::inline_string_calls(bool parse_time) {
1993   {
1994     // remove useless nodes to make the usage analysis simpler
1995     ResourceMark rm;
1996     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1997   }
1998 
1999   {
2000     ResourceMark rm;
2001     print_method(PHASE_BEFORE_STRINGOPTS, 3);
2002     PhaseStringOpts pso(initial_gvn(), for_igvn());
2003     print_method(PHASE_AFTER_STRINGOPTS, 3);
2004   }
2005 
2006   // now inline anything that we skipped the first time around
2007   if (!parse_time) {
2008     _late_inlines_pos = _late_inlines.length();
2009   }
2010 
2011   while (_string_late_inlines.length() > 0) {
2012     CallGenerator* cg = _string_late_inlines.pop();
2013     cg->do_late_inline();
2014     if (failing())  return;
2015   }
2016   _string_late_inlines.trunc_to(0);
2017 }
2018 
2019 // Late inlining of boxing methods
2020 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
2021   if (_boxing_late_inlines.length() > 0) {
2022     assert(has_boxed_value(), "inconsistent");
2023 
2024     PhaseGVN* gvn = initial_gvn();
2025     set_inlining_incrementally(true);
2026 
2027     assert( igvn._worklist.size() == 0, "should be done with igvn" );
2028     for_igvn()->clear();
2029     gvn->replace_with(&igvn);
2030 
2031     _late_inlines_pos = _late_inlines.length();
2032 
2033     while (_boxing_late_inlines.length() > 0) {
2034       CallGenerator* cg = _boxing_late_inlines.pop();
2035       cg->do_late_inline();
2036       if (failing())  return;
2037     }
2038     _boxing_late_inlines.trunc_to(0);
2039 
2040     {
2041       ResourceMark rm;
2042       PhaseRemoveUseless pru(gvn, for_igvn());
2043     }
2044 
2045     igvn = PhaseIterGVN(gvn);
2046     igvn.optimize();
2047 
2048     set_inlining_progress(false);
2049     set_inlining_incrementally(false);
2050   }
2051 }
2052 
2053 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
2054   assert(IncrementalInline, "incremental inlining should be on");
2055   PhaseGVN* gvn = initial_gvn();
2056 
2057   set_inlining_progress(false);
2058   for_igvn()->clear();
2059   gvn->replace_with(&igvn);
2060 
2061   {
2062     TracePhase tp("incrementalInline_inline", &timers[_t_incrInline_inline]);
2063     int i = 0;
2064     for (; i <_late_inlines.length() && !inlining_progress(); i++) {
2065       CallGenerator* cg = _late_inlines.at(i);
2066       _late_inlines_pos = i+1;
2067       cg->do_late_inline();
2068       if (failing())  return;
2069     }
2070     int j = 0;
2071     for (; i < _late_inlines.length(); i++, j++) {
2072       _late_inlines.at_put(j, _late_inlines.at(i));
2073     }
2074     _late_inlines.trunc_to(j);
2075   }
2076 
2077   {
2078     TracePhase tp("incrementalInline_pru", &timers[_t_incrInline_pru]);
2079     ResourceMark rm;
2080     PhaseRemoveUseless pru(gvn, for_igvn());
2081   }
2082 
2083   {
2084     TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
2085     igvn = PhaseIterGVN(gvn);
2086   }
2087 }
2088 
2089 // Perform incremental inlining until bound on number of live nodes is reached
2090 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
2091   TracePhase tp("incrementalInline", &timers[_t_incrInline]);
2092 
2093   PhaseGVN* gvn = initial_gvn();
2094 
2095   set_inlining_incrementally(true);
2096   set_inlining_progress(true);
2097   uint low_live_nodes = 0;
2098 
2099   while(inlining_progress() && _late_inlines.length() > 0) {
2100 
2101     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2102       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
2103         TracePhase tp("incrementalInline_ideal", &timers[_t_incrInline_ideal]);
2104         // PhaseIdealLoop is expensive so we only try it once we are
2105         // out of live nodes and we only try it again if the previous
2106         // helped got the number of nodes down significantly
2107         PhaseIdealLoop ideal_loop( igvn, false, true );
2108         if (failing())  return;
2109         low_live_nodes = live_nodes();
2110         _major_progress = true;
2111       }
2112 
2113       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2114         break;
2115       }
2116     }
2117 
2118     inline_incrementally_one(igvn);
2119 
2120     if (failing())  return;
2121 
2122     {
2123       TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
2124       igvn.optimize();
2125     }
2126 
2127     if (failing())  return;
2128   }
2129 
2130   assert( igvn._worklist.size() == 0, "should be done with igvn" );
2131 
2132   if (_string_late_inlines.length() > 0) {
2133     assert(has_stringbuilder(), "inconsistent");
2134     for_igvn()->clear();
2135     initial_gvn()->replace_with(&igvn);
2136 
2137     inline_string_calls(false);
2138 
2139     if (failing())  return;
2140 
2141     {
2142       TracePhase tp("incrementalInline_pru", &timers[_t_incrInline_pru]);
2143       ResourceMark rm;
2144       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2145     }
2146 
2147     {
2148       TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
2149       igvn = PhaseIterGVN(gvn);
2150       igvn.optimize();
2151     }
2152   }
2153 
2154   set_inlining_incrementally(false);
2155 }
2156 
2157 
2158 //------------------------------Optimize---------------------------------------
2159 // Given a graph, optimize it.
2160 void Compile::Optimize() {
2161   TracePhase tp("optimizer", &timers[_t_optimizer]);
2162 
2163 #ifndef PRODUCT
2164   if (_directive->BreakAtCompileOption) {
2165     BREAKPOINT;
2166   }
2167 
2168 #endif
2169 
2170 #ifdef ASSERT
2171   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2172   bs->verify_gc_barriers(true);
2173 #endif
2174 
2175   ResourceMark rm;
2176   int          loop_opts_cnt;
2177 
2178   print_inlining_reinit();
2179 
2180   NOT_PRODUCT( verify_graph_edges(); )
2181 
2182   print_method(PHASE_AFTER_PARSING);
2183 
2184  {
2185   // Iterative Global Value Numbering, including ideal transforms
2186   // Initialize IterGVN with types and values from parse-time GVN
2187   PhaseIterGVN igvn(initial_gvn());
2188 #ifdef ASSERT
2189   _modified_nodes = new (comp_arena()) Unique_Node_List(comp_arena());
2190 #endif
2191   {
2192     TracePhase tp("iterGVN", &timers[_t_iterGVN]);
2193     igvn.optimize();
2194   }
2195 
2196   print_method(PHASE_ITER_GVN1, 2);
2197 
2198   if (failing())  return;
2199 
2200   inline_incrementally(igvn);
2201 
2202   print_method(PHASE_INCREMENTAL_INLINE, 2);
2203 
2204   if (failing())  return;
2205 
2206   if (eliminate_boxing()) {
2207     // Inline valueOf() methods now.
2208     inline_boxing_calls(igvn);
2209 
2210     if (AlwaysIncrementalInline) {
2211       inline_incrementally(igvn);
2212     }
2213 
2214     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2215 
2216     if (failing())  return;
2217   }
2218 
2219   // Remove the speculative part of types and clean up the graph from
2220   // the extra CastPP nodes whose only purpose is to carry them. Do
2221   // that early so that optimizations are not disrupted by the extra
2222   // CastPP nodes.
2223   remove_speculative_types(igvn);
2224 
2225   // No more new expensive nodes will be added to the list from here
2226   // so keep only the actual candidates for optimizations.
2227   cleanup_expensive_nodes(igvn);
2228 
2229   if (!failing() && RenumberLiveNodes && live_nodes() + NodeLimitFudgeFactor < unique()) {
2230     Compile::TracePhase tp("", &timers[_t_renumberLive]);
2231     initial_gvn()->replace_with(&igvn);
2232     for_igvn()->clear();
2233     Unique_Node_List new_worklist(C->comp_arena());
2234     {
2235       ResourceMark rm;
2236       PhaseRenumberLive prl = PhaseRenumberLive(initial_gvn(), for_igvn(), &new_worklist);
2237     }
2238     set_for_igvn(&new_worklist);
2239     igvn = PhaseIterGVN(initial_gvn());
2240     igvn.optimize();
2241   }
2242 
2243   // Perform escape analysis
2244   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2245     if (has_loops()) {
2246       // Cleanup graph (remove dead nodes).
2247       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2248       PhaseIdealLoop ideal_loop( igvn, false, true );
2249       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2250       if (failing())  return;
2251     }
2252     ConnectionGraph::do_analysis(this, &igvn);
2253 
2254     if (failing())  return;
2255 
2256     // Optimize out fields loads from scalar replaceable allocations.
2257     igvn.optimize();
2258     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2259 
2260     if (failing())  return;
2261 
2262     if (congraph() != NULL && macro_count() > 0) {
2263       TracePhase tp("macroEliminate", &timers[_t_macroEliminate]);
2264       PhaseMacroExpand mexp(igvn);
2265       mexp.eliminate_macro_nodes();
2266       igvn.set_delay_transform(false);
2267 
2268       igvn.optimize();
2269       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2270 
2271       if (failing())  return;
2272     }
2273   }
2274 
2275   // Loop transforms on the ideal graph.  Range Check Elimination,
2276   // peeling, unrolling, etc.
2277 
2278   // Set loop opts counter
2279   loop_opts_cnt = num_loop_opts();
2280   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2281     {
2282       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2283       PhaseIdealLoop ideal_loop( igvn, true );
2284       loop_opts_cnt--;
2285       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2286       if (failing())  return;
2287     }
2288     // Loop opts pass if partial peeling occurred in previous pass
2289     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2290       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2291       PhaseIdealLoop ideal_loop( igvn, false );
2292       loop_opts_cnt--;
2293       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2294       if (failing())  return;
2295     }
2296     // Loop opts pass for loop-unrolling before CCP
2297     if(major_progress() && (loop_opts_cnt > 0)) {
2298       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2299       PhaseIdealLoop ideal_loop( igvn, false );
2300       loop_opts_cnt--;
2301       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2302     }
2303     if (!failing()) {
2304       // Verify that last round of loop opts produced a valid graph
2305       TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
2306       PhaseIdealLoop::verify(igvn);
2307     }
2308   }
2309   if (failing())  return;
2310 
2311   // Conditional Constant Propagation;
2312   PhaseCCP ccp( &igvn );
2313   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2314   {
2315     TracePhase tp("ccp", &timers[_t_ccp]);
2316     ccp.do_transform();
2317   }
2318   print_method(PHASE_CPP1, 2);
2319 
2320   assert( true, "Break here to ccp.dump_old2new_map()");
2321 
2322   // Iterative Global Value Numbering, including ideal transforms
2323   {
2324     TracePhase tp("iterGVN2", &timers[_t_iterGVN2]);
2325     igvn = ccp;
2326     igvn.optimize();
2327   }
2328 
2329   print_method(PHASE_ITER_GVN2, 2);
2330 
2331   if (failing())  return;
2332 
2333   // Loop transforms on the ideal graph.  Range Check Elimination,
2334   // peeling, unrolling, etc.
2335   if(loop_opts_cnt > 0) {
2336     debug_only( int cnt = 0; );
2337     while(major_progress() && (loop_opts_cnt > 0)) {
2338       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2339       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2340       PhaseIdealLoop ideal_loop( igvn, true);
2341       loop_opts_cnt--;
2342       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2343       if (failing())  return;
2344     }
2345   }
2346 
2347 #if INCLUDE_ZGC
2348   if (UseZGC) {
2349     ZBarrierSetC2::find_dominating_barriers(igvn);
2350   }
2351 #endif
2352 
2353   if (failing())  return;
2354 
2355   // Ensure that major progress is now clear
2356   C->clear_major_progress();
2357 
2358   {
2359     // Verify that all previous optimizations produced a valid graph
2360     // at least to this point, even if no loop optimizations were done.
2361     TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
2362     PhaseIdealLoop::verify(igvn);
2363   }
2364 
2365   if (range_check_cast_count() > 0) {
2366     // No more loop optimizations. Remove all range check dependent CastIINodes.
2367     C->remove_range_check_casts(igvn);
2368     igvn.optimize();
2369   }
2370 
2371 #ifdef ASSERT
2372   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2373   bs->verify_gc_barriers(false);
2374 #endif
2375 
2376   {
2377     TracePhase tp("macroExpand", &timers[_t_macroExpand]);
2378     PhaseMacroExpand  mex(igvn);
2379     print_method(PHASE_BEFORE_MACRO_EXPANSION, 2);
2380     if (mex.expand_macro_nodes()) {
2381       assert(failing(), "must bail out w/ explicit message");
2382       return;
2383     }
2384   }
2385 
2386   if (opaque4_count() > 0) {
2387     C->remove_opaque4_nodes(igvn);
2388     igvn.optimize();
2389   }
2390 
2391   DEBUG_ONLY( _modified_nodes = NULL; )
2392  } // (End scope of igvn; run destructor if necessary for asserts.)
2393 
2394  process_print_inlining();
2395  // A method with only infinite loops has no edges entering loops from root
2396  {
2397    TracePhase tp("graphReshape", &timers[_t_graphReshaping]);
2398    if (final_graph_reshaping()) {
2399      assert(failing(), "must bail out w/ explicit message");
2400      return;
2401    }
2402  }
2403 
2404  print_method(PHASE_OPTIMIZE_FINISHED, 2);
2405 }
2406 
2407 
2408 //------------------------------Code_Gen---------------------------------------
2409 // Given a graph, generate code for it
2410 void Compile::Code_Gen() {
2411   if (failing()) {
2412     return;
2413   }
2414 
2415   // Perform instruction selection.  You might think we could reclaim Matcher
2416   // memory PDQ, but actually the Matcher is used in generating spill code.
2417   // Internals of the Matcher (including some VectorSets) must remain live
2418   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2419   // set a bit in reclaimed memory.
2420 
2421   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2422   // nodes.  Mapping is only valid at the root of each matched subtree.
2423   NOT_PRODUCT( verify_graph_edges(); )
2424 
2425   Matcher matcher;
2426   _matcher = &matcher;
2427   {
2428     TracePhase tp("matcher", &timers[_t_matcher]);
2429     matcher.match();
2430   }
2431   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2432   // nodes.  Mapping is only valid at the root of each matched subtree.
2433   NOT_PRODUCT( verify_graph_edges(); )
2434 
2435   // If you have too many nodes, or if matching has failed, bail out
2436   check_node_count(0, "out of nodes matching instructions");
2437   if (failing()) {
2438     return;
2439   }
2440 
2441   print_method(PHASE_MATCHING, 2);
2442 
2443   // Build a proper-looking CFG
2444   PhaseCFG cfg(node_arena(), root(), matcher);
2445   _cfg = &cfg;
2446   {
2447     TracePhase tp("scheduler", &timers[_t_scheduler]);
2448     bool success = cfg.do_global_code_motion();
2449     if (!success) {
2450       return;
2451     }
2452 
2453     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2454     NOT_PRODUCT( verify_graph_edges(); )
2455     debug_only( cfg.verify(); )
2456   }
2457 
2458   PhaseChaitin regalloc(unique(), cfg, matcher, false);
2459   _regalloc = &regalloc;
2460   {
2461     TracePhase tp("regalloc", &timers[_t_registerAllocation]);
2462     // Perform register allocation.  After Chaitin, use-def chains are
2463     // no longer accurate (at spill code) and so must be ignored.
2464     // Node->LRG->reg mappings are still accurate.
2465     _regalloc->Register_Allocate();
2466 
2467     // Bail out if the allocator builds too many nodes
2468     if (failing()) {
2469       return;
2470     }
2471   }
2472 
2473   // Prior to register allocation we kept empty basic blocks in case the
2474   // the allocator needed a place to spill.  After register allocation we
2475   // are not adding any new instructions.  If any basic block is empty, we
2476   // can now safely remove it.
2477   {
2478     TracePhase tp("blockOrdering", &timers[_t_blockOrdering]);
2479     cfg.remove_empty_blocks();
2480     if (do_freq_based_layout()) {
2481       PhaseBlockLayout layout(cfg);
2482     } else {
2483       cfg.set_loop_alignment();
2484     }
2485     cfg.fixup_flow();
2486   }
2487 
2488   // Apply peephole optimizations
2489   if( OptoPeephole ) {
2490     TracePhase tp("peephole", &timers[_t_peephole]);
2491     PhasePeephole peep( _regalloc, cfg);
2492     peep.do_transform();
2493   }
2494 
2495   // Do late expand if CPU requires this.
2496   if (Matcher::require_postalloc_expand) {
2497     TracePhase tp("postalloc_expand", &timers[_t_postalloc_expand]);
2498     cfg.postalloc_expand(_regalloc);
2499   }
2500 
2501   // Convert Nodes to instruction bits in a buffer
2502   {
2503     TraceTime tp("output", &timers[_t_output], CITime);
2504     Output();
2505   }
2506 
2507   print_method(PHASE_FINAL_CODE);
2508 
2509   // He's dead, Jim.
2510   _cfg     = (PhaseCFG*)((intptr_t)0xdeadbeef);
2511   _regalloc = (PhaseChaitin*)((intptr_t)0xdeadbeef);
2512 }
2513 
2514 
2515 //------------------------------dump_asm---------------------------------------
2516 // Dump formatted assembly
2517 #ifndef PRODUCT
2518 void Compile::dump_asm(int *pcs, uint pc_limit) {
2519   bool cut_short = false;
2520   tty->print_cr("#");
2521   tty->print("#  ");  _tf->dump();  tty->cr();
2522   tty->print_cr("#");
2523 
2524   // For all blocks
2525   int pc = 0x0;                 // Program counter
2526   char starts_bundle = ' ';
2527   _regalloc->dump_frame();
2528 
2529   Node *n = NULL;
2530   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2531     if (VMThread::should_terminate()) {
2532       cut_short = true;
2533       break;
2534     }
2535     Block* block = _cfg->get_block(i);
2536     if (block->is_connector() && !Verbose) {
2537       continue;
2538     }
2539     n = block->head();
2540     if (pcs && n->_idx < pc_limit) {
2541       tty->print("%3.3x   ", pcs[n->_idx]);
2542     } else {
2543       tty->print("      ");
2544     }
2545     block->dump_head(_cfg);
2546     if (block->is_connector()) {
2547       tty->print_cr("        # Empty connector block");
2548     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2549       tty->print_cr("        # Block is sole successor of call");
2550     }
2551 
2552     // For all instructions
2553     Node *delay = NULL;
2554     for (uint j = 0; j < block->number_of_nodes(); j++) {
2555       if (VMThread::should_terminate()) {
2556         cut_short = true;
2557         break;
2558       }
2559       n = block->get_node(j);
2560       if (valid_bundle_info(n)) {
2561         Bundle* bundle = node_bundling(n);
2562         if (bundle->used_in_unconditional_delay()) {
2563           delay = n;
2564           continue;
2565         }
2566         if (bundle->starts_bundle()) {
2567           starts_bundle = '+';
2568         }
2569       }
2570 
2571       if (WizardMode) {
2572         n->dump();
2573       }
2574 
2575       if( !n->is_Region() &&    // Dont print in the Assembly
2576           !n->is_Phi() &&       // a few noisely useless nodes
2577           !n->is_Proj() &&
2578           !n->is_MachTemp() &&
2579           !n->is_SafePointScalarObject() &&
2580           !n->is_Catch() &&     // Would be nice to print exception table targets
2581           !n->is_MergeMem() &&  // Not very interesting
2582           !n->is_top() &&       // Debug info table constants
2583           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2584           ) {
2585         if (pcs && n->_idx < pc_limit)
2586           tty->print("%3.3x", pcs[n->_idx]);
2587         else
2588           tty->print("   ");
2589         tty->print(" %c ", starts_bundle);
2590         starts_bundle = ' ';
2591         tty->print("\t");
2592         n->format(_regalloc, tty);
2593         tty->cr();
2594       }
2595 
2596       // If we have an instruction with a delay slot, and have seen a delay,
2597       // then back up and print it
2598       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2599         assert(delay != NULL, "no unconditional delay instruction");
2600         if (WizardMode) delay->dump();
2601 
2602         if (node_bundling(delay)->starts_bundle())
2603           starts_bundle = '+';
2604         if (pcs && n->_idx < pc_limit)
2605           tty->print("%3.3x", pcs[n->_idx]);
2606         else
2607           tty->print("   ");
2608         tty->print(" %c ", starts_bundle);
2609         starts_bundle = ' ';
2610         tty->print("\t");
2611         delay->format(_regalloc, tty);
2612         tty->cr();
2613         delay = NULL;
2614       }
2615 
2616       // Dump the exception table as well
2617       if( n->is_Catch() && (Verbose || WizardMode) ) {
2618         // Print the exception table for this offset
2619         _handler_table.print_subtable_for(pc);
2620       }
2621     }
2622 
2623     if (pcs && n->_idx < pc_limit)
2624       tty->print_cr("%3.3x", pcs[n->_idx]);
2625     else
2626       tty->cr();
2627 
2628     assert(cut_short || delay == NULL, "no unconditional delay branch");
2629 
2630   } // End of per-block dump
2631   tty->cr();
2632 
2633   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2634 }
2635 #endif
2636 
2637 //------------------------------Final_Reshape_Counts---------------------------
2638 // This class defines counters to help identify when a method
2639 // may/must be executed using hardware with only 24-bit precision.
2640 struct Final_Reshape_Counts : public StackObj {
2641   int  _call_count;             // count non-inlined 'common' calls
2642   int  _float_count;            // count float ops requiring 24-bit precision
2643   int  _double_count;           // count double ops requiring more precision
2644   int  _java_call_count;        // count non-inlined 'java' calls
2645   int  _inner_loop_count;       // count loops which need alignment
2646   VectorSet _visited;           // Visitation flags
2647   Node_List _tests;             // Set of IfNodes & PCTableNodes
2648 
2649   Final_Reshape_Counts() :
2650     _call_count(0), _float_count(0), _double_count(0),
2651     _java_call_count(0), _inner_loop_count(0),
2652     _visited( Thread::current()->resource_area() ) { }
2653 
2654   void inc_call_count  () { _call_count  ++; }
2655   void inc_float_count () { _float_count ++; }
2656   void inc_double_count() { _double_count++; }
2657   void inc_java_call_count() { _java_call_count++; }
2658   void inc_inner_loop_count() { _inner_loop_count++; }
2659 
2660   int  get_call_count  () const { return _call_count  ; }
2661   int  get_float_count () const { return _float_count ; }
2662   int  get_double_count() const { return _double_count; }
2663   int  get_java_call_count() const { return _java_call_count; }
2664   int  get_inner_loop_count() const { return _inner_loop_count; }
2665 };
2666 
2667 #ifdef ASSERT
2668 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2669   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2670   // Make sure the offset goes inside the instance layout.
2671   return k->contains_field_offset(tp->offset());
2672   // Note that OffsetBot and OffsetTop are very negative.
2673 }
2674 #endif
2675 
2676 // Eliminate trivially redundant StoreCMs and accumulate their
2677 // precedence edges.
2678 void Compile::eliminate_redundant_card_marks(Node* n) {
2679   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2680   if (n->in(MemNode::Address)->outcnt() > 1) {
2681     // There are multiple users of the same address so it might be
2682     // possible to eliminate some of the StoreCMs
2683     Node* mem = n->in(MemNode::Memory);
2684     Node* adr = n->in(MemNode::Address);
2685     Node* val = n->in(MemNode::ValueIn);
2686     Node* prev = n;
2687     bool done = false;
2688     // Walk the chain of StoreCMs eliminating ones that match.  As
2689     // long as it's a chain of single users then the optimization is
2690     // safe.  Eliminating partially redundant StoreCMs would require
2691     // cloning copies down the other paths.
2692     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2693       if (adr == mem->in(MemNode::Address) &&
2694           val == mem->in(MemNode::ValueIn)) {
2695         // redundant StoreCM
2696         if (mem->req() > MemNode::OopStore) {
2697           // Hasn't been processed by this code yet.
2698           n->add_prec(mem->in(MemNode::OopStore));
2699         } else {
2700           // Already converted to precedence edge
2701           for (uint i = mem->req(); i < mem->len(); i++) {
2702             // Accumulate any precedence edges
2703             if (mem->in(i) != NULL) {
2704               n->add_prec(mem->in(i));
2705             }
2706           }
2707           // Everything above this point has been processed.
2708           done = true;
2709         }
2710         // Eliminate the previous StoreCM
2711         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2712         assert(mem->outcnt() == 0, "should be dead");
2713         mem->disconnect_inputs(NULL, this);
2714       } else {
2715         prev = mem;
2716       }
2717       mem = prev->in(MemNode::Memory);
2718     }
2719   }
2720 }
2721 
2722 //------------------------------final_graph_reshaping_impl----------------------
2723 // Implement items 1-5 from final_graph_reshaping below.
2724 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2725 
2726   if ( n->outcnt() == 0 ) return; // dead node
2727   uint nop = n->Opcode();
2728 
2729   // Check for 2-input instruction with "last use" on right input.
2730   // Swap to left input.  Implements item (2).
2731   if( n->req() == 3 &&          // two-input instruction
2732       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2733       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2734       n->in(2)->outcnt() == 1 &&// right use IS a last use
2735       !n->in(2)->is_Con() ) {   // right use is not a constant
2736     // Check for commutative opcode
2737     switch( nop ) {
2738     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2739     case Op_MaxI:  case Op_MinI:
2740     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2741     case Op_AndL:  case Op_XorL:  case Op_OrL:
2742     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2743       // Move "last use" input to left by swapping inputs
2744       n->swap_edges(1, 2);
2745       break;
2746     }
2747     default:
2748       break;
2749     }
2750   }
2751 
2752 #ifdef ASSERT
2753   if( n->is_Mem() ) {
2754     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2755     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2756             // oop will be recorded in oop map if load crosses safepoint
2757             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2758                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2759             "raw memory operations should have control edge");
2760   }
2761 #endif
2762   // Count FPU ops and common calls, implements item (3)
2763   switch( nop ) {
2764   // Count all float operations that may use FPU
2765   case Op_AddF:
2766   case Op_SubF:
2767   case Op_MulF:
2768   case Op_DivF:
2769   case Op_NegF:
2770   case Op_ModF:
2771   case Op_ConvI2F:
2772   case Op_ConF:
2773   case Op_CmpF:
2774   case Op_CmpF3:
2775   // case Op_ConvL2F: // longs are split into 32-bit halves
2776     frc.inc_float_count();
2777     break;
2778 
2779   case Op_ConvF2D:
2780   case Op_ConvD2F:
2781     frc.inc_float_count();
2782     frc.inc_double_count();
2783     break;
2784 
2785   // Count all double operations that may use FPU
2786   case Op_AddD:
2787   case Op_SubD:
2788   case Op_MulD:
2789   case Op_DivD:
2790   case Op_NegD:
2791   case Op_ModD:
2792   case Op_ConvI2D:
2793   case Op_ConvD2I:
2794   // case Op_ConvL2D: // handled by leaf call
2795   // case Op_ConvD2L: // handled by leaf call
2796   case Op_ConD:
2797   case Op_CmpD:
2798   case Op_CmpD3:
2799     frc.inc_double_count();
2800     break;
2801   case Op_Opaque1:              // Remove Opaque Nodes before matching
2802   case Op_Opaque2:              // Remove Opaque Nodes before matching
2803   case Op_Opaque3:
2804     n->subsume_by(n->in(1), this);
2805     break;
2806   case Op_CallStaticJava:
2807   case Op_CallJava:
2808   case Op_CallDynamicJava:
2809     frc.inc_java_call_count(); // Count java call site;
2810   case Op_CallRuntime:
2811   case Op_CallLeaf:
2812   case Op_CallLeafNoFP: {
2813     assert (n->is_Call(), "");
2814     CallNode *call = n->as_Call();
2815     // Count call sites where the FP mode bit would have to be flipped.
2816     // Do not count uncommon runtime calls:
2817     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2818     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2819     if (!call->is_CallStaticJava() || !call->as_CallStaticJava()->_name) {
2820       frc.inc_call_count();   // Count the call site
2821     } else {                  // See if uncommon argument is shared
2822       Node *n = call->in(TypeFunc::Parms);
2823       int nop = n->Opcode();
2824       // Clone shared simple arguments to uncommon calls, item (1).
2825       if (n->outcnt() > 1 &&
2826           !n->is_Proj() &&
2827           nop != Op_CreateEx &&
2828           nop != Op_CheckCastPP &&
2829           nop != Op_DecodeN &&
2830           nop != Op_DecodeNKlass &&
2831           !n->is_Mem() &&
2832           !n->is_Phi()) {
2833         Node *x = n->clone();
2834         call->set_req(TypeFunc::Parms, x);
2835       }
2836     }
2837     break;
2838   }
2839 
2840   case Op_StoreD:
2841   case Op_LoadD:
2842   case Op_LoadD_unaligned:
2843     frc.inc_double_count();
2844     goto handle_mem;
2845   case Op_StoreF:
2846   case Op_LoadF:
2847     frc.inc_float_count();
2848     goto handle_mem;
2849 
2850   case Op_StoreCM:
2851     {
2852       // Convert OopStore dependence into precedence edge
2853       Node* prec = n->in(MemNode::OopStore);
2854       n->del_req(MemNode::OopStore);
2855       n->add_prec(prec);
2856       eliminate_redundant_card_marks(n);
2857     }
2858 
2859     // fall through
2860 
2861   case Op_StoreB:
2862   case Op_StoreC:
2863   case Op_StorePConditional:
2864   case Op_StoreI:
2865   case Op_StoreL:
2866   case Op_StoreIConditional:
2867   case Op_StoreLConditional:
2868   case Op_CompareAndSwapB:
2869   case Op_CompareAndSwapS:
2870   case Op_CompareAndSwapI:
2871   case Op_CompareAndSwapL:
2872   case Op_CompareAndSwapP:
2873   case Op_CompareAndSwapN:
2874   case Op_WeakCompareAndSwapB:
2875   case Op_WeakCompareAndSwapS:
2876   case Op_WeakCompareAndSwapI:
2877   case Op_WeakCompareAndSwapL:
2878   case Op_WeakCompareAndSwapP:
2879   case Op_WeakCompareAndSwapN:
2880   case Op_CompareAndExchangeB:
2881   case Op_CompareAndExchangeS:
2882   case Op_CompareAndExchangeI:
2883   case Op_CompareAndExchangeL:
2884   case Op_CompareAndExchangeP:
2885   case Op_CompareAndExchangeN:
2886   case Op_GetAndAddS:
2887   case Op_GetAndAddB:
2888   case Op_GetAndAddI:
2889   case Op_GetAndAddL:
2890   case Op_GetAndSetS:
2891   case Op_GetAndSetB:
2892   case Op_GetAndSetI:
2893   case Op_GetAndSetL:
2894   case Op_GetAndSetP:
2895   case Op_GetAndSetN:
2896   case Op_StoreP:
2897   case Op_StoreN:
2898   case Op_StoreNKlass:
2899   case Op_LoadB:
2900   case Op_LoadUB:
2901   case Op_LoadUS:
2902   case Op_LoadI:
2903   case Op_LoadKlass:
2904   case Op_LoadNKlass:
2905   case Op_LoadL:
2906   case Op_LoadL_unaligned:
2907   case Op_LoadPLocked:
2908   case Op_LoadP:
2909 #if INCLUDE_ZGC
2910   case Op_LoadBarrierSlowReg:
2911   case Op_LoadBarrierWeakSlowReg:
2912 #endif
2913   case Op_LoadN:
2914   case Op_LoadRange:
2915   case Op_LoadS: {
2916   handle_mem:
2917 #ifdef ASSERT
2918     if( VerifyOptoOopOffsets ) {
2919       assert( n->is_Mem(), "" );
2920       MemNode *mem  = (MemNode*)n;
2921       // Check to see if address types have grounded out somehow.
2922       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2923       assert( !tp || oop_offset_is_sane(tp), "" );
2924     }
2925 #endif
2926     break;
2927   }
2928 
2929   case Op_AddP: {               // Assert sane base pointers
2930     Node *addp = n->in(AddPNode::Address);
2931     assert( !addp->is_AddP() ||
2932             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2933             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2934             "Base pointers must match (addp %u)", addp->_idx );
2935 #ifdef _LP64
2936     if ((UseCompressedOops || UseCompressedClassPointers) &&
2937         addp->Opcode() == Op_ConP &&
2938         addp == n->in(AddPNode::Base) &&
2939         n->in(AddPNode::Offset)->is_Con()) {
2940       // If the transformation of ConP to ConN+DecodeN is beneficial depends
2941       // on the platform and on the compressed oops mode.
2942       // Use addressing with narrow klass to load with offset on x86.
2943       // Some platforms can use the constant pool to load ConP.
2944       // Do this transformation here since IGVN will convert ConN back to ConP.
2945       const Type* t = addp->bottom_type();
2946       bool is_oop   = t->isa_oopptr() != NULL;
2947       bool is_klass = t->isa_klassptr() != NULL;
2948 
2949       if ((is_oop   && Matcher::const_oop_prefer_decode()  ) ||
2950           (is_klass && Matcher::const_klass_prefer_decode())) {
2951         Node* nn = NULL;
2952 
2953         int op = is_oop ? Op_ConN : Op_ConNKlass;
2954 
2955         // Look for existing ConN node of the same exact type.
2956         Node* r  = root();
2957         uint cnt = r->outcnt();
2958         for (uint i = 0; i < cnt; i++) {
2959           Node* m = r->raw_out(i);
2960           if (m!= NULL && m->Opcode() == op &&
2961               m->bottom_type()->make_ptr() == t) {
2962             nn = m;
2963             break;
2964           }
2965         }
2966         if (nn != NULL) {
2967           // Decode a narrow oop to match address
2968           // [R12 + narrow_oop_reg<<3 + offset]
2969           if (is_oop) {
2970             nn = new DecodeNNode(nn, t);
2971           } else {
2972             nn = new DecodeNKlassNode(nn, t);
2973           }
2974           // Check for succeeding AddP which uses the same Base.
2975           // Otherwise we will run into the assertion above when visiting that guy.
2976           for (uint i = 0; i < n->outcnt(); ++i) {
2977             Node *out_i = n->raw_out(i);
2978             if (out_i && out_i->is_AddP() && out_i->in(AddPNode::Base) == addp) {
2979               out_i->set_req(AddPNode::Base, nn);
2980 #ifdef ASSERT
2981               for (uint j = 0; j < out_i->outcnt(); ++j) {
2982                 Node *out_j = out_i->raw_out(j);
2983                 assert(out_j == NULL || !out_j->is_AddP() || out_j->in(AddPNode::Base) != addp,
2984                        "more than 2 AddP nodes in a chain (out_j %u)", out_j->_idx);
2985               }
2986 #endif
2987             }
2988           }
2989           n->set_req(AddPNode::Base, nn);
2990           n->set_req(AddPNode::Address, nn);
2991           if (addp->outcnt() == 0) {
2992             addp->disconnect_inputs(NULL, this);
2993           }
2994         }
2995       }
2996     }
2997 #endif
2998     // platform dependent reshaping of the address expression
2999     reshape_address(n->as_AddP());
3000     break;
3001   }
3002 
3003   case Op_CastPP: {
3004     // Remove CastPP nodes to gain more freedom during scheduling but
3005     // keep the dependency they encode as control or precedence edges
3006     // (if control is set already) on memory operations. Some CastPP
3007     // nodes don't have a control (don't carry a dependency): skip
3008     // those.
3009     if (n->in(0) != NULL) {
3010       ResourceMark rm;
3011       Unique_Node_List wq;
3012       wq.push(n);
3013       for (uint next = 0; next < wq.size(); ++next) {
3014         Node *m = wq.at(next);
3015         for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
3016           Node* use = m->fast_out(i);
3017           if (use->is_Mem() || use->is_EncodeNarrowPtr()) {
3018             use->ensure_control_or_add_prec(n->in(0));
3019           } else {
3020             switch(use->Opcode()) {
3021             case Op_AddP:
3022             case Op_DecodeN:
3023             case Op_DecodeNKlass:
3024             case Op_CheckCastPP:
3025             case Op_CastPP:
3026               wq.push(use);
3027               break;
3028             }
3029           }
3030         }
3031       }
3032     }
3033     const bool is_LP64 = LP64_ONLY(true) NOT_LP64(false);
3034     if (is_LP64 && n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
3035       Node* in1 = n->in(1);
3036       const Type* t = n->bottom_type();
3037       Node* new_in1 = in1->clone();
3038       new_in1->as_DecodeN()->set_type(t);
3039 
3040       if (!Matcher::narrow_oop_use_complex_address()) {
3041         //
3042         // x86, ARM and friends can handle 2 adds in addressing mode
3043         // and Matcher can fold a DecodeN node into address by using
3044         // a narrow oop directly and do implicit NULL check in address:
3045         //
3046         // [R12 + narrow_oop_reg<<3 + offset]
3047         // NullCheck narrow_oop_reg
3048         //
3049         // On other platforms (Sparc) we have to keep new DecodeN node and
3050         // use it to do implicit NULL check in address:
3051         //
3052         // decode_not_null narrow_oop_reg, base_reg
3053         // [base_reg + offset]
3054         // NullCheck base_reg
3055         //
3056         // Pin the new DecodeN node to non-null path on these platform (Sparc)
3057         // to keep the information to which NULL check the new DecodeN node
3058         // corresponds to use it as value in implicit_null_check().
3059         //
3060         new_in1->set_req(0, n->in(0));
3061       }
3062 
3063       n->subsume_by(new_in1, this);
3064       if (in1->outcnt() == 0) {
3065         in1->disconnect_inputs(NULL, this);
3066       }
3067     } else {
3068       n->subsume_by(n->in(1), this);
3069       if (n->outcnt() == 0) {
3070         n->disconnect_inputs(NULL, this);
3071       }
3072     }
3073     break;
3074   }
3075 #ifdef _LP64
3076   case Op_CmpP:
3077     // Do this transformation here to preserve CmpPNode::sub() and
3078     // other TypePtr related Ideal optimizations (for example, ptr nullness).
3079     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
3080       Node* in1 = n->in(1);
3081       Node* in2 = n->in(2);
3082       if (!in1->is_DecodeNarrowPtr()) {
3083         in2 = in1;
3084         in1 = n->in(2);
3085       }
3086       assert(in1->is_DecodeNarrowPtr(), "sanity");
3087 
3088       Node* new_in2 = NULL;
3089       if (in2->is_DecodeNarrowPtr()) {
3090         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
3091         new_in2 = in2->in(1);
3092       } else if (in2->Opcode() == Op_ConP) {
3093         const Type* t = in2->bottom_type();
3094         if (t == TypePtr::NULL_PTR) {
3095           assert(in1->is_DecodeN(), "compare klass to null?");
3096           // Don't convert CmpP null check into CmpN if compressed
3097           // oops implicit null check is not generated.
3098           // This will allow to generate normal oop implicit null check.
3099           if (Matcher::gen_narrow_oop_implicit_null_checks())
3100             new_in2 = ConNode::make(TypeNarrowOop::NULL_PTR);
3101           //
3102           // This transformation together with CastPP transformation above
3103           // will generated code for implicit NULL checks for compressed oops.
3104           //
3105           // The original code after Optimize()
3106           //
3107           //    LoadN memory, narrow_oop_reg
3108           //    decode narrow_oop_reg, base_reg
3109           //    CmpP base_reg, NULL
3110           //    CastPP base_reg // NotNull
3111           //    Load [base_reg + offset], val_reg
3112           //
3113           // after these transformations will be
3114           //
3115           //    LoadN memory, narrow_oop_reg
3116           //    CmpN narrow_oop_reg, NULL
3117           //    decode_not_null narrow_oop_reg, base_reg
3118           //    Load [base_reg + offset], val_reg
3119           //
3120           // and the uncommon path (== NULL) will use narrow_oop_reg directly
3121           // since narrow oops can be used in debug info now (see the code in
3122           // final_graph_reshaping_walk()).
3123           //
3124           // At the end the code will be matched to
3125           // on x86:
3126           //
3127           //    Load_narrow_oop memory, narrow_oop_reg
3128           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
3129           //    NullCheck narrow_oop_reg
3130           //
3131           // and on sparc:
3132           //
3133           //    Load_narrow_oop memory, narrow_oop_reg
3134           //    decode_not_null narrow_oop_reg, base_reg
3135           //    Load [base_reg + offset], val_reg
3136           //    NullCheck base_reg
3137           //
3138         } else if (t->isa_oopptr()) {
3139           new_in2 = ConNode::make(t->make_narrowoop());
3140         } else if (t->isa_klassptr()) {
3141           new_in2 = ConNode::make(t->make_narrowklass());
3142         }
3143       }
3144       if (new_in2 != NULL) {
3145         Node* cmpN = new CmpNNode(in1->in(1), new_in2);
3146         n->subsume_by(cmpN, this);
3147         if (in1->outcnt() == 0) {
3148           in1->disconnect_inputs(NULL, this);
3149         }
3150         if (in2->outcnt() == 0) {
3151           in2->disconnect_inputs(NULL, this);
3152         }
3153       }
3154     }
3155     break;
3156 
3157   case Op_DecodeN:
3158   case Op_DecodeNKlass:
3159     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
3160     // DecodeN could be pinned when it can't be fold into
3161     // an address expression, see the code for Op_CastPP above.
3162     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
3163     break;
3164 
3165   case Op_EncodeP:
3166   case Op_EncodePKlass: {
3167     Node* in1 = n->in(1);
3168     if (in1->is_DecodeNarrowPtr()) {
3169       n->subsume_by(in1->in(1), this);
3170     } else if (in1->Opcode() == Op_ConP) {
3171       const Type* t = in1->bottom_type();
3172       if (t == TypePtr::NULL_PTR) {
3173         assert(t->isa_oopptr(), "null klass?");
3174         n->subsume_by(ConNode::make(TypeNarrowOop::NULL_PTR), this);
3175       } else if (t->isa_oopptr()) {
3176         n->subsume_by(ConNode::make(t->make_narrowoop()), this);
3177       } else if (t->isa_klassptr()) {
3178         n->subsume_by(ConNode::make(t->make_narrowklass()), this);
3179       }
3180     }
3181     if (in1->outcnt() == 0) {
3182       in1->disconnect_inputs(NULL, this);
3183     }
3184     break;
3185   }
3186 
3187   case Op_Proj: {
3188     if (OptimizeStringConcat) {
3189       ProjNode* p = n->as_Proj();
3190       if (p->_is_io_use) {
3191         // Separate projections were used for the exception path which
3192         // are normally removed by a late inline.  If it wasn't inlined
3193         // then they will hang around and should just be replaced with
3194         // the original one.
3195         Node* proj = NULL;
3196         // Replace with just one
3197         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
3198           Node *use = i.get();
3199           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
3200             proj = use;
3201             break;
3202           }
3203         }
3204         assert(proj != NULL, "must be found");
3205         p->subsume_by(proj, this);
3206       }
3207     }
3208     break;
3209   }
3210 
3211   case Op_Phi:
3212     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
3213       // The EncodeP optimization may create Phi with the same edges
3214       // for all paths. It is not handled well by Register Allocator.
3215       Node* unique_in = n->in(1);
3216       assert(unique_in != NULL, "");
3217       uint cnt = n->req();
3218       for (uint i = 2; i < cnt; i++) {
3219         Node* m = n->in(i);
3220         assert(m != NULL, "");
3221         if (unique_in != m)
3222           unique_in = NULL;
3223       }
3224       if (unique_in != NULL) {
3225         n->subsume_by(unique_in, this);
3226       }
3227     }
3228     break;
3229 
3230 #endif
3231 
3232 #ifdef ASSERT
3233   case Op_CastII:
3234     // Verify that all range check dependent CastII nodes were removed.
3235     if (n->isa_CastII()->has_range_check()) {
3236       n->dump(3);
3237       assert(false, "Range check dependent CastII node was not removed");
3238     }
3239     break;
3240 #endif
3241 
3242   case Op_ModI:
3243     if (UseDivMod) {
3244       // Check if a%b and a/b both exist
3245       Node* d = n->find_similar(Op_DivI);
3246       if (d) {
3247         // Replace them with a fused divmod if supported
3248         if (Matcher::has_match_rule(Op_DivModI)) {
3249           DivModINode* divmod = DivModINode::make(n);
3250           d->subsume_by(divmod->div_proj(), this);
3251           n->subsume_by(divmod->mod_proj(), this);
3252         } else {
3253           // replace a%b with a-((a/b)*b)
3254           Node* mult = new MulINode(d, d->in(2));
3255           Node* sub  = new SubINode(d->in(1), mult);
3256           n->subsume_by(sub, this);
3257         }
3258       }
3259     }
3260     break;
3261 
3262   case Op_ModL:
3263     if (UseDivMod) {
3264       // Check if a%b and a/b both exist
3265       Node* d = n->find_similar(Op_DivL);
3266       if (d) {
3267         // Replace them with a fused divmod if supported
3268         if (Matcher::has_match_rule(Op_DivModL)) {
3269           DivModLNode* divmod = DivModLNode::make(n);
3270           d->subsume_by(divmod->div_proj(), this);
3271           n->subsume_by(divmod->mod_proj(), this);
3272         } else {
3273           // replace a%b with a-((a/b)*b)
3274           Node* mult = new MulLNode(d, d->in(2));
3275           Node* sub  = new SubLNode(d->in(1), mult);
3276           n->subsume_by(sub, this);
3277         }
3278       }
3279     }
3280     break;
3281 
3282   case Op_LoadVector:
3283   case Op_StoreVector:
3284     break;
3285 
3286   case Op_AddReductionVI:
3287   case Op_AddReductionVL:
3288   case Op_AddReductionVF:
3289   case Op_AddReductionVD:
3290   case Op_MulReductionVI:
3291   case Op_MulReductionVL:
3292   case Op_MulReductionVF:
3293   case Op_MulReductionVD:
3294     break;
3295 
3296   case Op_PackB:
3297   case Op_PackS:
3298   case Op_PackI:
3299   case Op_PackF:
3300   case Op_PackL:
3301   case Op_PackD:
3302     if (n->req()-1 > 2) {
3303       // Replace many operand PackNodes with a binary tree for matching
3304       PackNode* p = (PackNode*) n;
3305       Node* btp = p->binary_tree_pack(1, n->req());
3306       n->subsume_by(btp, this);
3307     }
3308     break;
3309   case Op_Loop:
3310   case Op_CountedLoop:
3311   case Op_OuterStripMinedLoop:
3312     if (n->as_Loop()->is_inner_loop()) {
3313       frc.inc_inner_loop_count();
3314     }
3315     n->as_Loop()->verify_strip_mined(0);
3316     break;
3317   case Op_LShiftI:
3318   case Op_RShiftI:
3319   case Op_URShiftI:
3320   case Op_LShiftL:
3321   case Op_RShiftL:
3322   case Op_URShiftL:
3323     if (Matcher::need_masked_shift_count) {
3324       // The cpu's shift instructions don't restrict the count to the
3325       // lower 5/6 bits. We need to do the masking ourselves.
3326       Node* in2 = n->in(2);
3327       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3328       const TypeInt* t = in2->find_int_type();
3329       if (t != NULL && t->is_con()) {
3330         juint shift = t->get_con();
3331         if (shift > mask) { // Unsigned cmp
3332           n->set_req(2, ConNode::make(TypeInt::make(shift & mask)));
3333         }
3334       } else {
3335         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3336           Node* shift = new AndINode(in2, ConNode::make(TypeInt::make(mask)));
3337           n->set_req(2, shift);
3338         }
3339       }
3340       if (in2->outcnt() == 0) { // Remove dead node
3341         in2->disconnect_inputs(NULL, this);
3342       }
3343     }
3344     break;
3345   case Op_MemBarStoreStore:
3346   case Op_MemBarRelease:
3347     // Break the link with AllocateNode: it is no longer useful and
3348     // confuses register allocation.
3349     if (n->req() > MemBarNode::Precedent) {
3350       n->set_req(MemBarNode::Precedent, top());
3351     }
3352     break;
3353   case Op_RangeCheck: {
3354     RangeCheckNode* rc = n->as_RangeCheck();
3355     Node* iff = new IfNode(rc->in(0), rc->in(1), rc->_prob, rc->_fcnt);
3356     n->subsume_by(iff, this);
3357     frc._tests.push(iff);
3358     break;
3359   }
3360   case Op_ConvI2L: {
3361     if (!Matcher::convi2l_type_required) {
3362       // Code generation on some platforms doesn't need accurate
3363       // ConvI2L types. Widening the type can help remove redundant
3364       // address computations.
3365       n->as_Type()->set_type(TypeLong::INT);
3366       ResourceMark rm;
3367       Node_List wq;
3368       wq.push(n);
3369       for (uint next = 0; next < wq.size(); next++) {
3370         Node *m = wq.at(next);
3371 
3372         for(;;) {
3373           // Loop over all nodes with identical inputs edges as m
3374           Node* k = m->find_similar(m->Opcode());
3375           if (k == NULL) {
3376             break;
3377           }
3378           // Push their uses so we get a chance to remove node made
3379           // redundant
3380           for (DUIterator_Fast imax, i = k->fast_outs(imax); i < imax; i++) {
3381             Node* u = k->fast_out(i);
3382             assert(!wq.contains(u), "shouldn't process one node several times");
3383             if (u->Opcode() == Op_LShiftL ||
3384                 u->Opcode() == Op_AddL ||
3385                 u->Opcode() == Op_SubL ||
3386                 u->Opcode() == Op_AddP) {
3387               wq.push(u);
3388             }
3389           }
3390           // Replace all nodes with identical edges as m with m
3391           k->subsume_by(m, this);
3392         }
3393       }
3394     }
3395     break;
3396   }
3397   case Op_CmpUL: {
3398     if (!Matcher::has_match_rule(Op_CmpUL)) {
3399       // No support for unsigned long comparisons
3400       ConINode* sign_pos = new ConINode(TypeInt::make(BitsPerLong - 1));
3401       Node* sign_bit_mask = new RShiftLNode(n->in(1), sign_pos);
3402       Node* orl = new OrLNode(n->in(1), sign_bit_mask);
3403       ConLNode* remove_sign_mask = new ConLNode(TypeLong::make(max_jlong));
3404       Node* andl = new AndLNode(orl, remove_sign_mask);
3405       Node* cmp = new CmpLNode(andl, n->in(2));
3406       n->subsume_by(cmp, this);
3407     }
3408     break;
3409   }
3410   default:
3411     assert( !n->is_Call(), "" );
3412     assert( !n->is_Mem(), "" );
3413     assert( nop != Op_ProfileBoolean, "should be eliminated during IGVN");
3414     break;
3415   }
3416 
3417   // Collect CFG split points
3418   if (n->is_MultiBranch() && !n->is_RangeCheck()) {
3419     frc._tests.push(n);
3420   }
3421 }
3422 
3423 //------------------------------final_graph_reshaping_walk---------------------
3424 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3425 // requires that the walk visits a node's inputs before visiting the node.
3426 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3427   ResourceArea *area = Thread::current()->resource_area();
3428   Unique_Node_List sfpt(area);
3429 
3430   frc._visited.set(root->_idx); // first, mark node as visited
3431   uint cnt = root->req();
3432   Node *n = root;
3433   uint  i = 0;
3434   while (true) {
3435     if (i < cnt) {
3436       // Place all non-visited non-null inputs onto stack
3437       Node* m = n->in(i);
3438       ++i;
3439       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3440         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3441           // compute worst case interpreter size in case of a deoptimization
3442           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3443 
3444           sfpt.push(m);
3445         }
3446         cnt = m->req();
3447         nstack.push(n, i); // put on stack parent and next input's index
3448         n = m;
3449         i = 0;
3450       }
3451     } else {
3452       // Now do post-visit work
3453       final_graph_reshaping_impl( n, frc );
3454       if (nstack.is_empty())
3455         break;             // finished
3456       n = nstack.node();   // Get node from stack
3457       cnt = n->req();
3458       i = nstack.index();
3459       nstack.pop();        // Shift to the next node on stack
3460     }
3461   }
3462 
3463   // Skip next transformation if compressed oops are not used.
3464   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3465       (!UseCompressedOops && !UseCompressedClassPointers))
3466     return;
3467 
3468   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3469   // It could be done for an uncommon traps or any safepoints/calls
3470   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3471   while (sfpt.size() > 0) {
3472     n = sfpt.pop();
3473     JVMState *jvms = n->as_SafePoint()->jvms();
3474     assert(jvms != NULL, "sanity");
3475     int start = jvms->debug_start();
3476     int end   = n->req();
3477     bool is_uncommon = (n->is_CallStaticJava() &&
3478                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3479     for (int j = start; j < end; j++) {
3480       Node* in = n->in(j);
3481       if (in->is_DecodeNarrowPtr()) {
3482         bool safe_to_skip = true;
3483         if (!is_uncommon ) {
3484           // Is it safe to skip?
3485           for (uint i = 0; i < in->outcnt(); i++) {
3486             Node* u = in->raw_out(i);
3487             if (!u->is_SafePoint() ||
3488                 (u->is_Call() && u->as_Call()->has_non_debug_use(n))) {
3489               safe_to_skip = false;
3490             }
3491           }
3492         }
3493         if (safe_to_skip) {
3494           n->set_req(j, in->in(1));
3495         }
3496         if (in->outcnt() == 0) {
3497           in->disconnect_inputs(NULL, this);
3498         }
3499       }
3500     }
3501   }
3502 }
3503 
3504 //------------------------------final_graph_reshaping--------------------------
3505 // Final Graph Reshaping.
3506 //
3507 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3508 //     and not commoned up and forced early.  Must come after regular
3509 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3510 //     inputs to Loop Phis; these will be split by the allocator anyways.
3511 //     Remove Opaque nodes.
3512 // (2) Move last-uses by commutative operations to the left input to encourage
3513 //     Intel update-in-place two-address operations and better register usage
3514 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3515 //     calls canonicalizing them back.
3516 // (3) Count the number of double-precision FP ops, single-precision FP ops
3517 //     and call sites.  On Intel, we can get correct rounding either by
3518 //     forcing singles to memory (requires extra stores and loads after each
3519 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3520 //     clearing the mode bit around call sites).  The mode bit is only used
3521 //     if the relative frequency of single FP ops to calls is low enough.
3522 //     This is a key transform for SPEC mpeg_audio.
3523 // (4) Detect infinite loops; blobs of code reachable from above but not
3524 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3525 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3526 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3527 //     Detection is by looking for IfNodes where only 1 projection is
3528 //     reachable from below or CatchNodes missing some targets.
3529 // (5) Assert for insane oop offsets in debug mode.
3530 
3531 bool Compile::final_graph_reshaping() {
3532   // an infinite loop may have been eliminated by the optimizer,
3533   // in which case the graph will be empty.
3534   if (root()->req() == 1) {
3535     record_method_not_compilable("trivial infinite loop");
3536     return true;
3537   }
3538 
3539   // Expensive nodes have their control input set to prevent the GVN
3540   // from freely commoning them. There's no GVN beyond this point so
3541   // no need to keep the control input. We want the expensive nodes to
3542   // be freely moved to the least frequent code path by gcm.
3543   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3544   for (int i = 0; i < expensive_count(); i++) {
3545     _expensive_nodes->at(i)->set_req(0, NULL);
3546   }
3547 
3548   Final_Reshape_Counts frc;
3549 
3550   // Visit everybody reachable!
3551   // Allocate stack of size C->live_nodes()/2 to avoid frequent realloc
3552   Node_Stack nstack(live_nodes() >> 1);
3553   final_graph_reshaping_walk(nstack, root(), frc);
3554 
3555   // Check for unreachable (from below) code (i.e., infinite loops).
3556   for( uint i = 0; i < frc._tests.size(); i++ ) {
3557     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3558     // Get number of CFG targets.
3559     // Note that PCTables include exception targets after calls.
3560     uint required_outcnt = n->required_outcnt();
3561     if (n->outcnt() != required_outcnt) {
3562       // Check for a few special cases.  Rethrow Nodes never take the
3563       // 'fall-thru' path, so expected kids is 1 less.
3564       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3565         if (n->in(0)->in(0)->is_Call()) {
3566           CallNode *call = n->in(0)->in(0)->as_Call();
3567           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3568             required_outcnt--;      // Rethrow always has 1 less kid
3569           } else if (call->req() > TypeFunc::Parms &&
3570                      call->is_CallDynamicJava()) {
3571             // Check for null receiver. In such case, the optimizer has
3572             // detected that the virtual call will always result in a null
3573             // pointer exception. The fall-through projection of this CatchNode
3574             // will not be populated.
3575             Node *arg0 = call->in(TypeFunc::Parms);
3576             if (arg0->is_Type() &&
3577                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3578               required_outcnt--;
3579             }
3580           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3581                      call->req() > TypeFunc::Parms+1 &&
3582                      call->is_CallStaticJava()) {
3583             // Check for negative array length. In such case, the optimizer has
3584             // detected that the allocation attempt will always result in an
3585             // exception. There is no fall-through projection of this CatchNode .
3586             Node *arg1 = call->in(TypeFunc::Parms+1);
3587             if (arg1->is_Type() &&
3588                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3589               required_outcnt--;
3590             }
3591           }
3592         }
3593       }
3594       // Recheck with a better notion of 'required_outcnt'
3595       if (n->outcnt() != required_outcnt) {
3596         record_method_not_compilable("malformed control flow");
3597         return true;            // Not all targets reachable!
3598       }
3599     }
3600     // Check that I actually visited all kids.  Unreached kids
3601     // must be infinite loops.
3602     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3603       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3604         record_method_not_compilable("infinite loop");
3605         return true;            // Found unvisited kid; must be unreach
3606       }
3607 
3608     // Here so verification code in final_graph_reshaping_walk()
3609     // always see an OuterStripMinedLoopEnd
3610     if (n->is_OuterStripMinedLoopEnd()) {
3611       IfNode* init_iff = n->as_If();
3612       Node* iff = new IfNode(init_iff->in(0), init_iff->in(1), init_iff->_prob, init_iff->_fcnt);
3613       n->subsume_by(iff, this);
3614     }
3615   }
3616 
3617   // If original bytecodes contained a mixture of floats and doubles
3618   // check if the optimizer has made it homogenous, item (3).
3619   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3620       frc.get_float_count() > 32 &&
3621       frc.get_double_count() == 0 &&
3622       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3623     set_24_bit_selection_and_mode( false,  true );
3624   }
3625 
3626   set_java_calls(frc.get_java_call_count());
3627   set_inner_loops(frc.get_inner_loop_count());
3628 
3629   // No infinite loops, no reason to bail out.
3630   return false;
3631 }
3632 
3633 //-----------------------------too_many_traps----------------------------------
3634 // Report if there are too many traps at the current method and bci.
3635 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3636 bool Compile::too_many_traps(ciMethod* method,
3637                              int bci,
3638                              Deoptimization::DeoptReason reason) {
3639   ciMethodData* md = method->method_data();
3640   if (md->is_empty()) {
3641     // Assume the trap has not occurred, or that it occurred only
3642     // because of a transient condition during start-up in the interpreter.
3643     return false;
3644   }
3645   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3646   if (md->has_trap_at(bci, m, reason) != 0) {
3647     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3648     // Also, if there are multiple reasons, or if there is no per-BCI record,
3649     // assume the worst.
3650     if (log())
3651       log()->elem("observe trap='%s' count='%d'",
3652                   Deoptimization::trap_reason_name(reason),
3653                   md->trap_count(reason));
3654     return true;
3655   } else {
3656     // Ignore method/bci and see if there have been too many globally.
3657     return too_many_traps(reason, md);
3658   }
3659 }
3660 
3661 // Less-accurate variant which does not require a method and bci.
3662 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3663                              ciMethodData* logmd) {
3664   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3665     // Too many traps globally.
3666     // Note that we use cumulative trap_count, not just md->trap_count.
3667     if (log()) {
3668       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3669       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3670                   Deoptimization::trap_reason_name(reason),
3671                   mcount, trap_count(reason));
3672     }
3673     return true;
3674   } else {
3675     // The coast is clear.
3676     return false;
3677   }
3678 }
3679 
3680 //--------------------------too_many_recompiles--------------------------------
3681 // Report if there are too many recompiles at the current method and bci.
3682 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3683 // Is not eager to return true, since this will cause the compiler to use
3684 // Action_none for a trap point, to avoid too many recompilations.
3685 bool Compile::too_many_recompiles(ciMethod* method,
3686                                   int bci,
3687                                   Deoptimization::DeoptReason reason) {
3688   ciMethodData* md = method->method_data();
3689   if (md->is_empty()) {
3690     // Assume the trap has not occurred, or that it occurred only
3691     // because of a transient condition during start-up in the interpreter.
3692     return false;
3693   }
3694   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3695   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3696   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3697   Deoptimization::DeoptReason per_bc_reason
3698     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3699   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3700   if ((per_bc_reason == Deoptimization::Reason_none
3701        || md->has_trap_at(bci, m, reason) != 0)
3702       // The trap frequency measure we care about is the recompile count:
3703       && md->trap_recompiled_at(bci, m)
3704       && md->overflow_recompile_count() >= bc_cutoff) {
3705     // Do not emit a trap here if it has already caused recompilations.
3706     // Also, if there are multiple reasons, or if there is no per-BCI record,
3707     // assume the worst.
3708     if (log())
3709       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3710                   Deoptimization::trap_reason_name(reason),
3711                   md->trap_count(reason),
3712                   md->overflow_recompile_count());
3713     return true;
3714   } else if (trap_count(reason) != 0
3715              && decompile_count() >= m_cutoff) {
3716     // Too many recompiles globally, and we have seen this sort of trap.
3717     // Use cumulative decompile_count, not just md->decompile_count.
3718     if (log())
3719       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3720                   Deoptimization::trap_reason_name(reason),
3721                   md->trap_count(reason), trap_count(reason),
3722                   md->decompile_count(), decompile_count());
3723     return true;
3724   } else {
3725     // The coast is clear.
3726     return false;
3727   }
3728 }
3729 
3730 // Compute when not to trap. Used by matching trap based nodes and
3731 // NullCheck optimization.
3732 void Compile::set_allowed_deopt_reasons() {
3733   _allowed_reasons = 0;
3734   if (is_method_compilation()) {
3735     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3736       assert(rs < BitsPerInt, "recode bit map");
3737       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3738         _allowed_reasons |= nth_bit(rs);
3739       }
3740     }
3741   }
3742 }
3743 
3744 bool Compile::is_compiling_clinit_for(ciKlass* k) {
3745   ciMethod* root = method(); // the root method of compilation
3746   return root->is_static_initializer() && root->holder() == k; // access in the context of clinit
3747 }
3748 
3749 #ifndef PRODUCT
3750 //------------------------------verify_graph_edges---------------------------
3751 // Walk the Graph and verify that there is a one-to-one correspondence
3752 // between Use-Def edges and Def-Use edges in the graph.
3753 void Compile::verify_graph_edges(bool no_dead_code) {
3754   if (VerifyGraphEdges) {
3755     ResourceArea *area = Thread::current()->resource_area();
3756     Unique_Node_List visited(area);
3757     // Call recursive graph walk to check edges
3758     _root->verify_edges(visited);
3759     if (no_dead_code) {
3760       // Now make sure that no visited node is used by an unvisited node.
3761       bool dead_nodes = false;
3762       Unique_Node_List checked(area);
3763       while (visited.size() > 0) {
3764         Node* n = visited.pop();
3765         checked.push(n);
3766         for (uint i = 0; i < n->outcnt(); i++) {
3767           Node* use = n->raw_out(i);
3768           if (checked.member(use))  continue;  // already checked
3769           if (visited.member(use))  continue;  // already in the graph
3770           if (use->is_Con())        continue;  // a dead ConNode is OK
3771           // At this point, we have found a dead node which is DU-reachable.
3772           if (!dead_nodes) {
3773             tty->print_cr("*** Dead nodes reachable via DU edges:");
3774             dead_nodes = true;
3775           }
3776           use->dump(2);
3777           tty->print_cr("---");
3778           checked.push(use);  // No repeats; pretend it is now checked.
3779         }
3780       }
3781       assert(!dead_nodes, "using nodes must be reachable from root");
3782     }
3783   }
3784 }
3785 
3786 // Verify GC barriers consistency
3787 // Currently supported:
3788 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3789 void Compile::verify_barriers() {
3790 #if INCLUDE_G1GC
3791   if (UseG1GC) {
3792     // Verify G1 pre-barriers
3793     const int marking_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset());
3794 
3795     ResourceArea *area = Thread::current()->resource_area();
3796     Unique_Node_List visited(area);
3797     Node_List worklist(area);
3798     // We're going to walk control flow backwards starting from the Root
3799     worklist.push(_root);
3800     while (worklist.size() > 0) {
3801       Node* x = worklist.pop();
3802       if (x == NULL || x == top()) continue;
3803       if (visited.member(x)) {
3804         continue;
3805       } else {
3806         visited.push(x);
3807       }
3808 
3809       if (x->is_Region()) {
3810         for (uint i = 1; i < x->req(); i++) {
3811           worklist.push(x->in(i));
3812         }
3813       } else {
3814         worklist.push(x->in(0));
3815         // We are looking for the pattern:
3816         //                            /->ThreadLocal
3817         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3818         //              \->ConI(0)
3819         // We want to verify that the If and the LoadB have the same control
3820         // See GraphKit::g1_write_barrier_pre()
3821         if (x->is_If()) {
3822           IfNode *iff = x->as_If();
3823           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3824             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3825             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3826                 && cmp->in(1)->is_Load()) {
3827               LoadNode* load = cmp->in(1)->as_Load();
3828               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3829                   && load->in(2)->in(3)->is_Con()
3830                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3831 
3832                 Node* if_ctrl = iff->in(0);
3833                 Node* load_ctrl = load->in(0);
3834 
3835                 if (if_ctrl != load_ctrl) {
3836                   // Skip possible CProj->NeverBranch in infinite loops
3837                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3838                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3839                     if_ctrl = if_ctrl->in(0)->in(0);
3840                   }
3841                 }
3842                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3843               }
3844             }
3845           }
3846         }
3847       }
3848     }
3849   }
3850 #endif
3851 }
3852 
3853 #endif
3854 
3855 // The Compile object keeps track of failure reasons separately from the ciEnv.
3856 // This is required because there is not quite a 1-1 relation between the
3857 // ciEnv and its compilation task and the Compile object.  Note that one
3858 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3859 // to backtrack and retry without subsuming loads.  Other than this backtracking
3860 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3861 // by the logic in C2Compiler.
3862 void Compile::record_failure(const char* reason) {
3863   if (log() != NULL) {
3864     log()->elem("failure reason='%s' phase='compile'", reason);
3865   }
3866   if (_failure_reason == NULL) {
3867     // Record the first failure reason.
3868     _failure_reason = reason;
3869   }
3870 
3871   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3872     C->print_method(PHASE_FAILURE);
3873   }
3874   _root = NULL;  // flush the graph, too
3875 }
3876 
3877 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator)
3878   : TraceTime(name, accumulator, CITime, CITimeVerbose),
3879     _phase_name(name), _dolog(CITimeVerbose)
3880 {
3881   if (_dolog) {
3882     C = Compile::current();
3883     _log = C->log();
3884   } else {
3885     C = NULL;
3886     _log = NULL;
3887   }
3888   if (_log != NULL) {
3889     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3890     _log->stamp();
3891     _log->end_head();
3892   }
3893 }
3894 
3895 Compile::TracePhase::~TracePhase() {
3896 
3897   C = Compile::current();
3898   if (_dolog) {
3899     _log = C->log();
3900   } else {
3901     _log = NULL;
3902   }
3903 
3904 #ifdef ASSERT
3905   if (PrintIdealNodeCount) {
3906     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3907                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3908   }
3909 
3910   if (VerifyIdealNodeCount) {
3911     Compile::current()->print_missing_nodes();
3912   }
3913 #endif
3914 
3915   if (_log != NULL) {
3916     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3917   }
3918 }
3919 
3920 //=============================================================================
3921 // Two Constant's are equal when the type and the value are equal.
3922 bool Compile::Constant::operator==(const Constant& other) {
3923   if (type()          != other.type()         )  return false;
3924   if (can_be_reused() != other.can_be_reused())  return false;
3925   // For floating point values we compare the bit pattern.
3926   switch (type()) {
3927   case T_INT:
3928   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3929   case T_LONG:
3930   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3931   case T_OBJECT:
3932   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3933   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3934   case T_METADATA: return (_v._metadata == other._v._metadata);
3935   default: ShouldNotReachHere(); return false;
3936   }
3937 }
3938 
3939 static int type_to_size_in_bytes(BasicType t) {
3940   switch (t) {
3941   case T_INT:     return sizeof(jint   );
3942   case T_LONG:    return sizeof(jlong  );
3943   case T_FLOAT:   return sizeof(jfloat );
3944   case T_DOUBLE:  return sizeof(jdouble);
3945   case T_METADATA: return sizeof(Metadata*);
3946     // We use T_VOID as marker for jump-table entries (labels) which
3947     // need an internal word relocation.
3948   case T_VOID:
3949   case T_ADDRESS:
3950   case T_OBJECT:  return sizeof(jobject);
3951   default:
3952     ShouldNotReachHere();
3953     return -1;
3954   }
3955 }
3956 
3957 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3958   // sort descending
3959   if (a->freq() > b->freq())  return -1;
3960   if (a->freq() < b->freq())  return  1;
3961   return 0;
3962 }
3963 
3964 void Compile::ConstantTable::calculate_offsets_and_size() {
3965   // First, sort the array by frequencies.
3966   _constants.sort(qsort_comparator);
3967 
3968 #ifdef ASSERT
3969   // Make sure all jump-table entries were sorted to the end of the
3970   // array (they have a negative frequency).
3971   bool found_void = false;
3972   for (int i = 0; i < _constants.length(); i++) {
3973     Constant con = _constants.at(i);
3974     if (con.type() == T_VOID)
3975       found_void = true;  // jump-tables
3976     else
3977       assert(!found_void, "wrong sorting");
3978   }
3979 #endif
3980 
3981   int offset = 0;
3982   for (int i = 0; i < _constants.length(); i++) {
3983     Constant* con = _constants.adr_at(i);
3984 
3985     // Align offset for type.
3986     int typesize = type_to_size_in_bytes(con->type());
3987     offset = align_up(offset, typesize);
3988     con->set_offset(offset);   // set constant's offset
3989 
3990     if (con->type() == T_VOID) {
3991       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3992       offset = offset + typesize * n->outcnt();  // expand jump-table
3993     } else {
3994       offset = offset + typesize;
3995     }
3996   }
3997 
3998   // Align size up to the next section start (which is insts; see
3999   // CodeBuffer::align_at_start).
4000   assert(_size == -1, "already set?");
4001   _size = align_up(offset, (int)CodeEntryAlignment);
4002 }
4003 
4004 void Compile::ConstantTable::emit(CodeBuffer& cb) {
4005   MacroAssembler _masm(&cb);
4006   for (int i = 0; i < _constants.length(); i++) {
4007     Constant con = _constants.at(i);
4008     address constant_addr = NULL;
4009     switch (con.type()) {
4010     case T_INT:    constant_addr = _masm.int_constant(   con.get_jint()   ); break;
4011     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
4012     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
4013     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
4014     case T_OBJECT: {
4015       jobject obj = con.get_jobject();
4016       int oop_index = _masm.oop_recorder()->find_index(obj);
4017       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
4018       break;
4019     }
4020     case T_ADDRESS: {
4021       address addr = (address) con.get_jobject();
4022       constant_addr = _masm.address_constant(addr);
4023       break;
4024     }
4025     // We use T_VOID as marker for jump-table entries (labels) which
4026     // need an internal word relocation.
4027     case T_VOID: {
4028       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
4029       // Fill the jump-table with a dummy word.  The real value is
4030       // filled in later in fill_jump_table.
4031       address dummy = (address) n;
4032       constant_addr = _masm.address_constant(dummy);
4033       // Expand jump-table
4034       for (uint i = 1; i < n->outcnt(); i++) {
4035         address temp_addr = _masm.address_constant(dummy + i);
4036         assert(temp_addr, "consts section too small");
4037       }
4038       break;
4039     }
4040     case T_METADATA: {
4041       Metadata* obj = con.get_metadata();
4042       int metadata_index = _masm.oop_recorder()->find_index(obj);
4043       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
4044       break;
4045     }
4046     default: ShouldNotReachHere();
4047     }
4048     assert(constant_addr, "consts section too small");
4049     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
4050             "must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset()));
4051   }
4052 }
4053 
4054 int Compile::ConstantTable::find_offset(Constant& con) const {
4055   int idx = _constants.find(con);
4056   guarantee(idx != -1, "constant must be in constant table");
4057   int offset = _constants.at(idx).offset();
4058   guarantee(offset != -1, "constant table not emitted yet?");
4059   return offset;
4060 }
4061 
4062 void Compile::ConstantTable::add(Constant& con) {
4063   if (con.can_be_reused()) {
4064     int idx = _constants.find(con);
4065     if (idx != -1 && _constants.at(idx).can_be_reused()) {
4066       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
4067       return;
4068     }
4069   }
4070   (void) _constants.append(con);
4071 }
4072 
4073 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
4074   Block* b = Compile::current()->cfg()->get_block_for_node(n);
4075   Constant con(type, value, b->_freq);
4076   add(con);
4077   return con;
4078 }
4079 
4080 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
4081   Constant con(metadata);
4082   add(con);
4083   return con;
4084 }
4085 
4086 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
4087   jvalue value;
4088   BasicType type = oper->type()->basic_type();
4089   switch (type) {
4090   case T_LONG:    value.j = oper->constantL(); break;
4091   case T_FLOAT:   value.f = oper->constantF(); break;
4092   case T_DOUBLE:  value.d = oper->constantD(); break;
4093   case T_OBJECT:
4094   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
4095   case T_METADATA: return add((Metadata*)oper->constant()); break;
4096   default: guarantee(false, "unhandled type: %s", type2name(type));
4097   }
4098   return add(n, type, value);
4099 }
4100 
4101 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
4102   jvalue value;
4103   // We can use the node pointer here to identify the right jump-table
4104   // as this method is called from Compile::Fill_buffer right before
4105   // the MachNodes are emitted and the jump-table is filled (means the
4106   // MachNode pointers do not change anymore).
4107   value.l = (jobject) n;
4108   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
4109   add(con);
4110   return con;
4111 }
4112 
4113 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
4114   // If called from Compile::scratch_emit_size do nothing.
4115   if (Compile::current()->in_scratch_emit_size())  return;
4116 
4117   assert(labels.is_nonempty(), "must be");
4118   assert((uint) labels.length() == n->outcnt(), "must be equal: %d == %d", labels.length(), n->outcnt());
4119 
4120   // Since MachConstantNode::constant_offset() also contains
4121   // table_base_offset() we need to subtract the table_base_offset()
4122   // to get the plain offset into the constant table.
4123   int offset = n->constant_offset() - table_base_offset();
4124 
4125   MacroAssembler _masm(&cb);
4126   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
4127 
4128   for (uint i = 0; i < n->outcnt(); i++) {
4129     address* constant_addr = &jump_table_base[i];
4130     assert(*constant_addr == (((address) n) + i), "all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, p2i(*constant_addr), p2i(((address) n) + i));
4131     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
4132     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
4133   }
4134 }
4135 
4136 //----------------------------static_subtype_check-----------------------------
4137 // Shortcut important common cases when superklass is exact:
4138 // (0) superklass is java.lang.Object (can occur in reflective code)
4139 // (1) subklass is already limited to a subtype of superklass => always ok
4140 // (2) subklass does not overlap with superklass => always fail
4141 // (3) superklass has NO subtypes and we can check with a simple compare.
4142 int Compile::static_subtype_check(ciKlass* superk, ciKlass* subk) {
4143   if (StressReflectiveCode) {
4144     return SSC_full_test;       // Let caller generate the general case.
4145   }
4146 
4147   if (superk == env()->Object_klass()) {
4148     return SSC_always_true;     // (0) this test cannot fail
4149   }
4150 
4151   ciType* superelem = superk;
4152   if (superelem->is_array_klass())
4153     superelem = superelem->as_array_klass()->base_element_type();
4154 
4155   if (!subk->is_interface()) {  // cannot trust static interface types yet
4156     if (subk->is_subtype_of(superk)) {
4157       return SSC_always_true;   // (1) false path dead; no dynamic test needed
4158     }
4159     if (!(superelem->is_klass() && superelem->as_klass()->is_interface()) &&
4160         !superk->is_subtype_of(subk)) {
4161       return SSC_always_false;
4162     }
4163   }
4164 
4165   // If casting to an instance klass, it must have no subtypes
4166   if (superk->is_interface()) {
4167     // Cannot trust interfaces yet.
4168     // %%% S.B. superk->nof_implementors() == 1
4169   } else if (superelem->is_instance_klass()) {
4170     ciInstanceKlass* ik = superelem->as_instance_klass();
4171     if (!ik->has_subklass() && !ik->is_interface()) {
4172       if (!ik->is_final()) {
4173         // Add a dependency if there is a chance of a later subclass.
4174         dependencies()->assert_leaf_type(ik);
4175       }
4176       return SSC_easy_test;     // (3) caller can do a simple ptr comparison
4177     }
4178   } else {
4179     // A primitive array type has no subtypes.
4180     return SSC_easy_test;       // (3) caller can do a simple ptr comparison
4181   }
4182 
4183   return SSC_full_test;
4184 }
4185 
4186 Node* Compile::conv_I2X_index(PhaseGVN* phase, Node* idx, const TypeInt* sizetype, Node* ctrl) {
4187 #ifdef _LP64
4188   // The scaled index operand to AddP must be a clean 64-bit value.
4189   // Java allows a 32-bit int to be incremented to a negative
4190   // value, which appears in a 64-bit register as a large
4191   // positive number.  Using that large positive number as an
4192   // operand in pointer arithmetic has bad consequences.
4193   // On the other hand, 32-bit overflow is rare, and the possibility
4194   // can often be excluded, if we annotate the ConvI2L node with
4195   // a type assertion that its value is known to be a small positive
4196   // number.  (The prior range check has ensured this.)
4197   // This assertion is used by ConvI2LNode::Ideal.
4198   int index_max = max_jint - 1;  // array size is max_jint, index is one less
4199   if (sizetype != NULL) index_max = sizetype->_hi - 1;
4200   const TypeInt* iidxtype = TypeInt::make(0, index_max, Type::WidenMax);
4201   idx = constrained_convI2L(phase, idx, iidxtype, ctrl);
4202 #endif
4203   return idx;
4204 }
4205 
4206 // Convert integer value to a narrowed long type dependent on ctrl (for example, a range check)
4207 Node* Compile::constrained_convI2L(PhaseGVN* phase, Node* value, const TypeInt* itype, Node* ctrl) {
4208   if (ctrl != NULL) {
4209     // Express control dependency by a CastII node with a narrow type.
4210     value = new CastIINode(value, itype, false, true /* range check dependency */);
4211     // Make the CastII node dependent on the control input to prevent the narrowed ConvI2L
4212     // node from floating above the range check during loop optimizations. Otherwise, the
4213     // ConvI2L node may be eliminated independently of the range check, causing the data path
4214     // to become TOP while the control path is still there (although it's unreachable).
4215     value->set_req(0, ctrl);
4216     // Save CastII node to remove it after loop optimizations.
4217     phase->C->add_range_check_cast(value);
4218     value = phase->transform(value);
4219   }
4220   const TypeLong* ltype = TypeLong::make(itype->_lo, itype->_hi, itype->_widen);
4221   return phase->transform(new ConvI2LNode(value, ltype));
4222 }
4223 
4224 // The message about the current inlining is accumulated in
4225 // _print_inlining_stream and transfered into the _print_inlining_list
4226 // once we know whether inlining succeeds or not. For regular
4227 // inlining, messages are appended to the buffer pointed by
4228 // _print_inlining_idx in the _print_inlining_list. For late inlining,
4229 // a new buffer is added after _print_inlining_idx in the list. This
4230 // way we can update the inlining message for late inlining call site
4231 // when the inlining is attempted again.
4232 void Compile::print_inlining_init() {
4233   if (print_inlining() || print_intrinsics()) {
4234     _print_inlining_stream = new stringStream();
4235     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
4236   }
4237 }
4238 
4239 void Compile::print_inlining_reinit() {
4240   if (print_inlining() || print_intrinsics()) {
4241     // Re allocate buffer when we change ResourceMark
4242     _print_inlining_stream = new stringStream();
4243   }
4244 }
4245 
4246 void Compile::print_inlining_reset() {
4247   _print_inlining_stream->reset();
4248 }
4249 
4250 void Compile::print_inlining_commit() {
4251   assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
4252   // Transfer the message from _print_inlining_stream to the current
4253   // _print_inlining_list buffer and clear _print_inlining_stream.
4254   _print_inlining_list->at(_print_inlining_idx).ss()->write(_print_inlining_stream->as_string(), _print_inlining_stream->size());
4255   print_inlining_reset();
4256 }
4257 
4258 void Compile::print_inlining_push() {
4259   // Add new buffer to the _print_inlining_list at current position
4260   _print_inlining_idx++;
4261   _print_inlining_list->insert_before(_print_inlining_idx, PrintInliningBuffer());
4262 }
4263 
4264 Compile::PrintInliningBuffer& Compile::print_inlining_current() {
4265   return _print_inlining_list->at(_print_inlining_idx);
4266 }
4267 
4268 void Compile::print_inlining_update(CallGenerator* cg) {
4269   if (print_inlining() || print_intrinsics()) {
4270     if (!cg->is_late_inline()) {
4271       if (print_inlining_current().cg() != NULL) {
4272         print_inlining_push();
4273       }
4274       print_inlining_commit();
4275     } else {
4276       if (print_inlining_current().cg() != cg &&
4277           (print_inlining_current().cg() != NULL ||
4278            print_inlining_current().ss()->size() != 0)) {
4279         print_inlining_push();
4280       }
4281       print_inlining_commit();
4282       print_inlining_current().set_cg(cg);
4283     }
4284   }
4285 }
4286 
4287 void Compile::print_inlining_move_to(CallGenerator* cg) {
4288   // We resume inlining at a late inlining call site. Locate the
4289   // corresponding inlining buffer so that we can update it.
4290   if (print_inlining()) {
4291     for (int i = 0; i < _print_inlining_list->length(); i++) {
4292       if (_print_inlining_list->adr_at(i)->cg() == cg) {
4293         _print_inlining_idx = i;
4294         return;
4295       }
4296     }
4297     ShouldNotReachHere();
4298   }
4299 }
4300 
4301 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
4302   if (print_inlining()) {
4303     assert(_print_inlining_stream->size() > 0, "missing inlining msg");
4304     assert(print_inlining_current().cg() == cg, "wrong entry");
4305     // replace message with new message
4306     _print_inlining_list->at_put(_print_inlining_idx, PrintInliningBuffer());
4307     print_inlining_commit();
4308     print_inlining_current().set_cg(cg);
4309   }
4310 }
4311 
4312 void Compile::print_inlining_assert_ready() {
4313   assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
4314 }
4315 
4316 void Compile::process_print_inlining() {
4317   bool do_print_inlining = print_inlining() || print_intrinsics();
4318   if (do_print_inlining || log() != NULL) {
4319     // Print inlining message for candidates that we couldn't inline
4320     // for lack of space
4321     for (int i = 0; i < _late_inlines.length(); i++) {
4322       CallGenerator* cg = _late_inlines.at(i);
4323       if (!cg->is_mh_late_inline()) {
4324         const char* msg = "live nodes > LiveNodeCountInliningCutoff";
4325         if (do_print_inlining) {
4326           cg->print_inlining_late(msg);
4327         }
4328         log_late_inline_failure(cg, msg);
4329       }
4330     }
4331   }
4332   if (do_print_inlining) {
4333     ResourceMark rm;
4334     stringStream ss;
4335     for (int i = 0; i < _print_inlining_list->length(); i++) {
4336       ss.print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
4337     }
4338     size_t end = ss.size();
4339     _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
4340     strncpy(_print_inlining_output, ss.base(), end+1);
4341     _print_inlining_output[end] = 0;
4342   }
4343 }
4344 
4345 void Compile::dump_print_inlining() {
4346   if (_print_inlining_output != NULL) {
4347     tty->print_raw(_print_inlining_output);
4348   }
4349 }
4350 
4351 void Compile::log_late_inline(CallGenerator* cg) {
4352   if (log() != NULL) {
4353     log()->head("late_inline method='%d'  inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
4354                 cg->unique_id());
4355     JVMState* p = cg->call_node()->jvms();
4356     while (p != NULL) {
4357       log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
4358       p = p->caller();
4359     }
4360     log()->tail("late_inline");
4361   }
4362 }
4363 
4364 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
4365   log_late_inline(cg);
4366   if (log() != NULL) {
4367     log()->inline_fail(msg);
4368   }
4369 }
4370 
4371 void Compile::log_inline_id(CallGenerator* cg) {
4372   if (log() != NULL) {
4373     // The LogCompilation tool needs a unique way to identify late
4374     // inline call sites. This id must be unique for this call site in
4375     // this compilation. Try to have it unique across compilations as
4376     // well because it can be convenient when grepping through the log
4377     // file.
4378     // Distinguish OSR compilations from others in case CICountOSR is
4379     // on.
4380     jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
4381     cg->set_unique_id(id);
4382     log()->elem("inline_id id='" JLONG_FORMAT "'", id);
4383   }
4384 }
4385 
4386 void Compile::log_inline_failure(const char* msg) {
4387   if (C->log() != NULL) {
4388     C->log()->inline_fail(msg);
4389   }
4390 }
4391 
4392 
4393 // Dump inlining replay data to the stream.
4394 // Don't change thread state and acquire any locks.
4395 void Compile::dump_inline_data(outputStream* out) {
4396   InlineTree* inl_tree = ilt();
4397   if (inl_tree != NULL) {
4398     out->print(" inline %d", inl_tree->count());
4399     inl_tree->dump_replay_data(out);
4400   }
4401 }
4402 
4403 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
4404   if (n1->Opcode() < n2->Opcode())      return -1;
4405   else if (n1->Opcode() > n2->Opcode()) return 1;
4406 
4407   assert(n1->req() == n2->req(), "can't compare %s nodes: n1->req() = %d, n2->req() = %d", NodeClassNames[n1->Opcode()], n1->req(), n2->req());
4408   for (uint i = 1; i < n1->req(); i++) {
4409     if (n1->in(i) < n2->in(i))      return -1;
4410     else if (n1->in(i) > n2->in(i)) return 1;
4411   }
4412 
4413   return 0;
4414 }
4415 
4416 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
4417   Node* n1 = *n1p;
4418   Node* n2 = *n2p;
4419 
4420   return cmp_expensive_nodes(n1, n2);
4421 }
4422 
4423 void Compile::sort_expensive_nodes() {
4424   if (!expensive_nodes_sorted()) {
4425     _expensive_nodes->sort(cmp_expensive_nodes);
4426   }
4427 }
4428 
4429 bool Compile::expensive_nodes_sorted() const {
4430   for (int i = 1; i < _expensive_nodes->length(); i++) {
4431     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
4432       return false;
4433     }
4434   }
4435   return true;
4436 }
4437 
4438 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
4439   if (_expensive_nodes->length() == 0) {
4440     return false;
4441   }
4442 
4443   assert(OptimizeExpensiveOps, "optimization off?");
4444 
4445   // Take this opportunity to remove dead nodes from the list
4446   int j = 0;
4447   for (int i = 0; i < _expensive_nodes->length(); i++) {
4448     Node* n = _expensive_nodes->at(i);
4449     if (!n->is_unreachable(igvn)) {
4450       assert(n->is_expensive(), "should be expensive");
4451       _expensive_nodes->at_put(j, n);
4452       j++;
4453     }
4454   }
4455   _expensive_nodes->trunc_to(j);
4456 
4457   // Then sort the list so that similar nodes are next to each other
4458   // and check for at least two nodes of identical kind with same data
4459   // inputs.
4460   sort_expensive_nodes();
4461 
4462   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
4463     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
4464       return true;
4465     }
4466   }
4467 
4468   return false;
4469 }
4470 
4471 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4472   if (_expensive_nodes->length() == 0) {
4473     return;
4474   }
4475 
4476   assert(OptimizeExpensiveOps, "optimization off?");
4477 
4478   // Sort to bring similar nodes next to each other and clear the
4479   // control input of nodes for which there's only a single copy.
4480   sort_expensive_nodes();
4481 
4482   int j = 0;
4483   int identical = 0;
4484   int i = 0;
4485   bool modified = false;
4486   for (; i < _expensive_nodes->length()-1; i++) {
4487     assert(j <= i, "can't write beyond current index");
4488     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
4489       identical++;
4490       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4491       continue;
4492     }
4493     if (identical > 0) {
4494       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4495       identical = 0;
4496     } else {
4497       Node* n = _expensive_nodes->at(i);
4498       igvn.replace_input_of(n, 0, NULL);
4499       igvn.hash_insert(n);
4500       modified = true;
4501     }
4502   }
4503   if (identical > 0) {
4504     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4505   } else if (_expensive_nodes->length() >= 1) {
4506     Node* n = _expensive_nodes->at(i);
4507     igvn.replace_input_of(n, 0, NULL);
4508     igvn.hash_insert(n);
4509     modified = true;
4510   }
4511   _expensive_nodes->trunc_to(j);
4512   if (modified) {
4513     igvn.optimize();
4514   }
4515 }
4516 
4517 void Compile::add_expensive_node(Node * n) {
4518   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4519   assert(n->is_expensive(), "expensive nodes with non-null control here only");
4520   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4521   if (OptimizeExpensiveOps) {
4522     _expensive_nodes->append(n);
4523   } else {
4524     // Clear control input and let IGVN optimize expensive nodes if
4525     // OptimizeExpensiveOps is off.
4526     n->set_req(0, NULL);
4527   }
4528 }
4529 
4530 /**
4531  * Remove the speculative part of types and clean up the graph
4532  */
4533 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4534   if (UseTypeSpeculation) {
4535     Unique_Node_List worklist;
4536     worklist.push(root());
4537     int modified = 0;
4538     // Go over all type nodes that carry a speculative type, drop the
4539     // speculative part of the type and enqueue the node for an igvn
4540     // which may optimize it out.
4541     for (uint next = 0; next < worklist.size(); ++next) {
4542       Node *n  = worklist.at(next);
4543       if (n->is_Type()) {
4544         TypeNode* tn = n->as_Type();
4545         const Type* t = tn->type();
4546         const Type* t_no_spec = t->remove_speculative();
4547         if (t_no_spec != t) {
4548           bool in_hash = igvn.hash_delete(n);
4549           assert(in_hash, "node should be in igvn hash table");
4550           tn->set_type(t_no_spec);
4551           igvn.hash_insert(n);
4552           igvn._worklist.push(n); // give it a chance to go away
4553           modified++;
4554         }
4555       }
4556       uint max = n->len();
4557       for( uint i = 0; i < max; ++i ) {
4558         Node *m = n->in(i);
4559         if (not_a_node(m))  continue;
4560         worklist.push(m);
4561       }
4562     }
4563     // Drop the speculative part of all types in the igvn's type table
4564     igvn.remove_speculative_types();
4565     if (modified > 0) {
4566       igvn.optimize();
4567     }
4568 #ifdef ASSERT
4569     // Verify that after the IGVN is over no speculative type has resurfaced
4570     worklist.clear();
4571     worklist.push(root());
4572     for (uint next = 0; next < worklist.size(); ++next) {
4573       Node *n  = worklist.at(next);
4574       const Type* t = igvn.type_or_null(n);
4575       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4576       if (n->is_Type()) {
4577         t = n->as_Type()->type();
4578         assert(t == t->remove_speculative(), "no more speculative types");
4579       }
4580       uint max = n->len();
4581       for( uint i = 0; i < max; ++i ) {
4582         Node *m = n->in(i);
4583         if (not_a_node(m))  continue;
4584         worklist.push(m);
4585       }
4586     }
4587     igvn.check_no_speculative_types();
4588 #endif
4589   }
4590 }
4591 
4592 // Auxiliary method to support randomized stressing/fuzzing.
4593 //
4594 // This method can be called the arbitrary number of times, with current count
4595 // as the argument. The logic allows selecting a single candidate from the
4596 // running list of candidates as follows:
4597 //    int count = 0;
4598 //    Cand* selected = null;
4599 //    while(cand = cand->next()) {
4600 //      if (randomized_select(++count)) {
4601 //        selected = cand;
4602 //      }
4603 //    }
4604 //
4605 // Including count equalizes the chances any candidate is "selected".
4606 // This is useful when we don't have the complete list of candidates to choose
4607 // from uniformly. In this case, we need to adjust the randomicity of the
4608 // selection, or else we will end up biasing the selection towards the latter
4609 // candidates.
4610 //
4611 // Quick back-envelope calculation shows that for the list of n candidates
4612 // the equal probability for the candidate to persist as "best" can be
4613 // achieved by replacing it with "next" k-th candidate with the probability
4614 // of 1/k. It can be easily shown that by the end of the run, the
4615 // probability for any candidate is converged to 1/n, thus giving the
4616 // uniform distribution among all the candidates.
4617 //
4618 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4619 #define RANDOMIZED_DOMAIN_POW 29
4620 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4621 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4622 bool Compile::randomized_select(int count) {
4623   assert(count > 0, "only positive");
4624   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4625 }
4626 
4627 CloneMap&     Compile::clone_map()                 { return _clone_map; }
4628 void          Compile::set_clone_map(Dict* d)      { _clone_map._dict = d; }
4629 
4630 void NodeCloneInfo::dump() const {
4631   tty->print(" {%d:%d} ", idx(), gen());
4632 }
4633 
4634 void CloneMap::clone(Node* old, Node* nnn, int gen) {
4635   uint64_t val = value(old->_idx);
4636   NodeCloneInfo cio(val);
4637   assert(val != 0, "old node should be in the map");
4638   NodeCloneInfo cin(cio.idx(), gen + cio.gen());
4639   insert(nnn->_idx, cin.get());
4640 #ifndef PRODUCT
4641   if (is_debug()) {
4642     tty->print_cr("CloneMap::clone inserted node %d info {%d:%d} into CloneMap", nnn->_idx, cin.idx(), cin.gen());
4643   }
4644 #endif
4645 }
4646 
4647 void CloneMap::verify_insert_and_clone(Node* old, Node* nnn, int gen) {
4648   NodeCloneInfo cio(value(old->_idx));
4649   if (cio.get() == 0) {
4650     cio.set(old->_idx, 0);
4651     insert(old->_idx, cio.get());
4652 #ifndef PRODUCT
4653     if (is_debug()) {
4654       tty->print_cr("CloneMap::verify_insert_and_clone inserted node %d info {%d:%d} into CloneMap", old->_idx, cio.idx(), cio.gen());
4655     }
4656 #endif
4657   }
4658   clone(old, nnn, gen);
4659 }
4660 
4661 int CloneMap::max_gen() const {
4662   int g = 0;
4663   DictI di(_dict);
4664   for(; di.test(); ++di) {
4665     int t = gen(di._key);
4666     if (g < t) {
4667       g = t;
4668 #ifndef PRODUCT
4669       if (is_debug()) {
4670         tty->print_cr("CloneMap::max_gen() update max=%d from %d", g, _2_node_idx_t(di._key));
4671       }
4672 #endif
4673     }
4674   }
4675   return g;
4676 }
4677 
4678 void CloneMap::dump(node_idx_t key) const {
4679   uint64_t val = value(key);
4680   if (val != 0) {
4681     NodeCloneInfo ni(val);
4682     ni.dump();
4683   }
4684 }