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