1 /*
   2  * Copyright (c) 1997, 2013, 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/compileLog.hpp"
  33 #include "compiler/disassembler.hpp"
  34 #include "compiler/oopMap.hpp"
  35 #include "opto/addnode.hpp"
  36 #include "opto/block.hpp"
  37 #include "opto/c2compiler.hpp"
  38 #include "opto/callGenerator.hpp"
  39 #include "opto/callnode.hpp"
  40 #include "opto/cfgnode.hpp"
  41 #include "opto/chaitin.hpp"
  42 #include "opto/compile.hpp"
  43 #include "opto/connode.hpp"
  44 #include "opto/divnode.hpp"
  45 #include "opto/escape.hpp"
  46 #include "opto/idealGraphPrinter.hpp"
  47 #include "opto/loopnode.hpp"
  48 #include "opto/machnode.hpp"
  49 #include "opto/macro.hpp"
  50 #include "opto/matcher.hpp"
  51 #include "opto/mathexactnode.hpp"
  52 #include "opto/memnode.hpp"
  53 #include "opto/mulnode.hpp"
  54 #include "opto/node.hpp"
  55 #include "opto/opcodes.hpp"
  56 #include "opto/output.hpp"
  57 #include "opto/parse.hpp"
  58 #include "opto/phaseX.hpp"
  59 #include "opto/rootnode.hpp"
  60 #include "opto/runtime.hpp"
  61 #include "opto/stringopts.hpp"
  62 #include "opto/type.hpp"
  63 #include "opto/vectornode.hpp"
  64 #include "runtime/arguments.hpp"
  65 #include "runtime/signature.hpp"
  66 #include "runtime/stubRoutines.hpp"
  67 #include "runtime/timer.hpp"
  68 #include "trace/tracing.hpp"
  69 #include "utilities/copy.hpp"
  70 #ifdef TARGET_ARCH_MODEL_x86_32
  71 # include "adfiles/ad_x86_32.hpp"
  72 #endif
  73 #ifdef TARGET_ARCH_MODEL_x86_64
  74 # include "adfiles/ad_x86_64.hpp"
  75 #endif
  76 #ifdef TARGET_ARCH_MODEL_sparc
  77 # include "adfiles/ad_sparc.hpp"
  78 #endif
  79 #ifdef TARGET_ARCH_MODEL_zero
  80 # include "adfiles/ad_zero.hpp"
  81 #endif
  82 #ifdef TARGET_ARCH_MODEL_arm
  83 # include "adfiles/ad_arm.hpp"
  84 #endif
  85 #ifdef TARGET_ARCH_MODEL_ppc
  86 # include "adfiles/ad_ppc.hpp"
  87 #endif
  88 
  89 
  90 // -------------------- Compile::mach_constant_base_node -----------------------
  91 // Constant table base node singleton.
  92 MachConstantBaseNode* Compile::mach_constant_base_node() {
  93   if (_mach_constant_base_node == NULL) {
  94     _mach_constant_base_node = new (C) MachConstantBaseNode();
  95     _mach_constant_base_node->add_req(C->root());
  96   }
  97   return _mach_constant_base_node;
  98 }
  99 
 100 
 101 /// Support for intrinsics.
 102 
 103 // Return the index at which m must be inserted (or already exists).
 104 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 105 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
 106 #ifdef ASSERT
 107   for (int i = 1; i < _intrinsics->length(); i++) {
 108     CallGenerator* cg1 = _intrinsics->at(i-1);
 109     CallGenerator* cg2 = _intrinsics->at(i);
 110     assert(cg1->method() != cg2->method()
 111            ? cg1->method()     < cg2->method()
 112            : cg1->is_virtual() < cg2->is_virtual(),
 113            "compiler intrinsics list must stay sorted");
 114   }
 115 #endif
 116   // Binary search sorted list, in decreasing intervals [lo, hi].
 117   int lo = 0, hi = _intrinsics->length()-1;
 118   while (lo <= hi) {
 119     int mid = (uint)(hi + lo) / 2;
 120     ciMethod* mid_m = _intrinsics->at(mid)->method();
 121     if (m < mid_m) {
 122       hi = mid-1;
 123     } else if (m > mid_m) {
 124       lo = mid+1;
 125     } else {
 126       // look at minor sort key
 127       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 128       if (is_virtual < mid_virt) {
 129         hi = mid-1;
 130       } else if (is_virtual > mid_virt) {
 131         lo = mid+1;
 132       } else {
 133         return mid;  // exact match
 134       }
 135     }
 136   }
 137   return lo;  // inexact match
 138 }
 139 
 140 void Compile::register_intrinsic(CallGenerator* cg) {
 141   if (_intrinsics == NULL) {
 142     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 143   }
 144   // This code is stolen from ciObjectFactory::insert.
 145   // Really, GrowableArray should have methods for
 146   // insert_at, remove_at, and binary_search.
 147   int len = _intrinsics->length();
 148   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 149   if (index == len) {
 150     _intrinsics->append(cg);
 151   } else {
 152 #ifdef ASSERT
 153     CallGenerator* oldcg = _intrinsics->at(index);
 154     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 155 #endif
 156     _intrinsics->append(_intrinsics->at(len-1));
 157     int pos;
 158     for (pos = len-2; pos >= index; pos--) {
 159       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 160     }
 161     _intrinsics->at_put(index, cg);
 162   }
 163   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 164 }
 165 
 166 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 167   assert(m->is_loaded(), "don't try this on unloaded methods");
 168   if (_intrinsics != NULL) {
 169     int index = intrinsic_insertion_index(m, is_virtual);
 170     if (index < _intrinsics->length()
 171         && _intrinsics->at(index)->method() == m
 172         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 173       return _intrinsics->at(index);
 174     }
 175   }
 176   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 177   if (m->intrinsic_id() != vmIntrinsics::_none &&
 178       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 179     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 180     if (cg != NULL) {
 181       // Save it for next time:
 182       register_intrinsic(cg);
 183       return cg;
 184     } else {
 185       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 186     }
 187   }
 188   return NULL;
 189 }
 190 
 191 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 192 // in library_call.cpp.
 193 
 194 
 195 #ifndef PRODUCT
 196 // statistics gathering...
 197 
 198 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 199 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 200 
 201 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 202   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 203   int oflags = _intrinsic_hist_flags[id];
 204   assert(flags != 0, "what happened?");
 205   if (is_virtual) {
 206     flags |= _intrinsic_virtual;
 207   }
 208   bool changed = (flags != oflags);
 209   if ((flags & _intrinsic_worked) != 0) {
 210     juint count = (_intrinsic_hist_count[id] += 1);
 211     if (count == 1) {
 212       changed = true;           // first time
 213     }
 214     // increment the overall count also:
 215     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 216   }
 217   if (changed) {
 218     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 219       // Something changed about the intrinsic's virtuality.
 220       if ((flags & _intrinsic_virtual) != 0) {
 221         // This is the first use of this intrinsic as a virtual call.
 222         if (oflags != 0) {
 223           // We already saw it as a non-virtual, so note both cases.
 224           flags |= _intrinsic_both;
 225         }
 226       } else if ((oflags & _intrinsic_both) == 0) {
 227         // This is the first use of this intrinsic as a non-virtual
 228         flags |= _intrinsic_both;
 229       }
 230     }
 231     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 232   }
 233   // update the overall flags also:
 234   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 235   return changed;
 236 }
 237 
 238 static char* format_flags(int flags, char* buf) {
 239   buf[0] = 0;
 240   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 241   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 242   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 243   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 244   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 245   if (buf[0] == 0)  strcat(buf, ",");
 246   assert(buf[0] == ',', "must be");
 247   return &buf[1];
 248 }
 249 
 250 void Compile::print_intrinsic_statistics() {
 251   char flagsbuf[100];
 252   ttyLocker ttyl;
 253   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 254   tty->print_cr("Compiler intrinsic usage:");
 255   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 256   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 257   #define PRINT_STAT_LINE(name, c, f) \
 258     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 259   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 260     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 261     int   flags = _intrinsic_hist_flags[id];
 262     juint count = _intrinsic_hist_count[id];
 263     if ((flags | count) != 0) {
 264       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 265     }
 266   }
 267   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 268   if (xtty != NULL)  xtty->tail("statistics");
 269 }
 270 
 271 void Compile::print_statistics() {
 272   { ttyLocker ttyl;
 273     if (xtty != NULL)  xtty->head("statistics type='opto'");
 274     Parse::print_statistics();
 275     PhaseCCP::print_statistics();
 276     PhaseRegAlloc::print_statistics();
 277     Scheduling::print_statistics();
 278     PhasePeephole::print_statistics();
 279     PhaseIdealLoop::print_statistics();
 280     if (xtty != NULL)  xtty->tail("statistics");
 281   }
 282   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 283     // put this under its own <statistics> element.
 284     print_intrinsic_statistics();
 285   }
 286 }
 287 #endif //PRODUCT
 288 
 289 // Support for bundling info
 290 Bundle* Compile::node_bundling(const Node *n) {
 291   assert(valid_bundle_info(n), "oob");
 292   return &_node_bundling_base[n->_idx];
 293 }
 294 
 295 bool Compile::valid_bundle_info(const Node *n) {
 296   return (_node_bundling_limit > n->_idx);
 297 }
 298 
 299 
 300 void Compile::gvn_replace_by(Node* n, Node* nn) {
 301   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 302     Node* use = n->last_out(i);
 303     bool is_in_table = initial_gvn()->hash_delete(use);
 304     uint uses_found = 0;
 305     for (uint j = 0; j < use->len(); j++) {
 306       if (use->in(j) == n) {
 307         if (j < use->req())
 308           use->set_req(j, nn);
 309         else
 310           use->set_prec(j, nn);
 311         uses_found++;
 312       }
 313     }
 314     if (is_in_table) {
 315       // reinsert into table
 316       initial_gvn()->hash_find_insert(use);
 317     }
 318     record_for_igvn(use);
 319     i -= uses_found;    // we deleted 1 or more copies of this edge
 320   }
 321 }
 322 
 323 
 324 static inline bool not_a_node(const Node* n) {
 325   if (n == NULL)                   return true;
 326   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 327   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 328   return false;
 329 }
 330 
 331 // Identify all nodes that are reachable from below, useful.
 332 // Use breadth-first pass that records state in a Unique_Node_List,
 333 // recursive traversal is slower.
 334 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 335   int estimated_worklist_size = unique();
 336   useful.map( estimated_worklist_size, NULL );  // preallocate space
 337 
 338   // Initialize worklist
 339   if (root() != NULL)     { useful.push(root()); }
 340   // If 'top' is cached, declare it useful to preserve cached node
 341   if( cached_top_node() ) { useful.push(cached_top_node()); }
 342 
 343   // Push all useful nodes onto the list, breadthfirst
 344   for( uint next = 0; next < useful.size(); ++next ) {
 345     assert( next < unique(), "Unique useful nodes < total nodes");
 346     Node *n  = useful.at(next);
 347     uint max = n->len();
 348     for( uint i = 0; i < max; ++i ) {
 349       Node *m = n->in(i);
 350       if (not_a_node(m))  continue;
 351       useful.push(m);
 352     }
 353   }
 354 }
 355 
 356 // Update dead_node_list with any missing dead nodes using useful
 357 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 358 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 359   uint max_idx = unique();
 360   VectorSet& useful_node_set = useful.member_set();
 361 
 362   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 363     // If node with index node_idx is not in useful set,
 364     // mark it as dead in dead node list.
 365     if (! useful_node_set.test(node_idx) ) {
 366       record_dead_node(node_idx);
 367     }
 368   }
 369 }
 370 
 371 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 372   int shift = 0;
 373   for (int i = 0; i < inlines->length(); i++) {
 374     CallGenerator* cg = inlines->at(i);
 375     CallNode* call = cg->call_node();
 376     if (shift > 0) {
 377       inlines->at_put(i-shift, cg);
 378     }
 379     if (!useful.member(call)) {
 380       shift++;
 381     }
 382   }
 383   inlines->trunc_to(inlines->length()-shift);
 384 }
 385 
 386 // Disconnect all useless nodes by disconnecting those at the boundary.
 387 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 388   uint next = 0;
 389   while (next < useful.size()) {
 390     Node *n = useful.at(next++);
 391     // Use raw traversal of out edges since this code removes out edges
 392     int max = n->outcnt();
 393     for (int j = 0; j < max; ++j) {
 394       Node* child = n->raw_out(j);
 395       if (! useful.member(child)) {
 396         assert(!child->is_top() || child != top(),
 397                "If top is cached in Compile object it is in useful list");
 398         // Only need to remove this out-edge to the useless node
 399         n->raw_del_out(j);
 400         --j;
 401         --max;
 402       }
 403     }
 404     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 405       record_for_igvn(n->unique_out());
 406     }
 407   }
 408   // Remove useless macro and predicate opaq nodes
 409   for (int i = C->macro_count()-1; i >= 0; i--) {
 410     Node* n = C->macro_node(i);
 411     if (!useful.member(n)) {
 412       remove_macro_node(n);
 413     }
 414   }
 415   // Remove useless expensive node
 416   for (int i = C->expensive_count()-1; i >= 0; i--) {
 417     Node* n = C->expensive_node(i);
 418     if (!useful.member(n)) {
 419       remove_expensive_node(n);
 420     }
 421   }
 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 // ============================================================================
 440 //------------------------------CompileWrapper---------------------------------
 441 class CompileWrapper : public StackObj {
 442   Compile *const _compile;
 443  public:
 444   CompileWrapper(Compile* compile);
 445 
 446   ~CompileWrapper();
 447 };
 448 
 449 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 450   // the Compile* pointer is stored in the current ciEnv:
 451   ciEnv* env = compile->env();
 452   assert(env == ciEnv::current(), "must already be a ciEnv active");
 453   assert(env->compiler_data() == NULL, "compile already active?");
 454   env->set_compiler_data(compile);
 455   assert(compile == Compile::current(), "sanity");
 456 
 457   compile->set_type_dict(NULL);
 458   compile->set_type_hwm(NULL);
 459   compile->set_type_last_size(0);
 460   compile->set_last_tf(NULL, NULL);
 461   compile->set_indexSet_arena(NULL);
 462   compile->set_indexSet_free_block_list(NULL);
 463   compile->init_type_arena();
 464   Type::Initialize(compile);
 465   _compile->set_scratch_buffer_blob(NULL);
 466   _compile->begin_method();
 467 }
 468 CompileWrapper::~CompileWrapper() {
 469   _compile->end_method();
 470   if (_compile->scratch_buffer_blob() != NULL)
 471     BufferBlob::free(_compile->scratch_buffer_blob());
 472   _compile->env()->set_compiler_data(NULL);
 473 }
 474 
 475 
 476 //----------------------------print_compile_messages---------------------------
 477 void Compile::print_compile_messages() {
 478 #ifndef PRODUCT
 479   // Check if recompiling
 480   if (_subsume_loads == false && PrintOpto) {
 481     // Recompiling without allowing machine instructions to subsume loads
 482     tty->print_cr("*********************************************************");
 483     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 484     tty->print_cr("*********************************************************");
 485   }
 486   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 487     // Recompiling without escape analysis
 488     tty->print_cr("*********************************************************");
 489     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 490     tty->print_cr("*********************************************************");
 491   }
 492   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 493     // Recompiling without boxing elimination
 494     tty->print_cr("*********************************************************");
 495     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 496     tty->print_cr("*********************************************************");
 497   }
 498   if (env()->break_at_compile()) {
 499     // Open the debugger when compiling this method.
 500     tty->print("### Breaking when compiling: ");
 501     method()->print_short_name();
 502     tty->cr();
 503     BREAKPOINT;
 504   }
 505 
 506   if( PrintOpto ) {
 507     if (is_osr_compilation()) {
 508       tty->print("[OSR]%3d", _compile_id);
 509     } else {
 510       tty->print("%3d", _compile_id);
 511     }
 512   }
 513 #endif
 514 }
 515 
 516 
 517 //-----------------------init_scratch_buffer_blob------------------------------
 518 // Construct a temporary BufferBlob and cache it for this compile.
 519 void Compile::init_scratch_buffer_blob(int const_size) {
 520   // If there is already a scratch buffer blob allocated and the
 521   // constant section is big enough, use it.  Otherwise free the
 522   // current and allocate a new one.
 523   BufferBlob* blob = scratch_buffer_blob();
 524   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 525     // Use the current blob.
 526   } else {
 527     if (blob != NULL) {
 528       BufferBlob::free(blob);
 529     }
 530 
 531     ResourceMark rm;
 532     _scratch_const_size = const_size;
 533     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 534     blob = BufferBlob::create("Compile::scratch_buffer", size);
 535     // Record the buffer blob for next time.
 536     set_scratch_buffer_blob(blob);
 537     // Have we run out of code space?
 538     if (scratch_buffer_blob() == NULL) {
 539       // Let CompilerBroker disable further compilations.
 540       record_failure("Not enough space for scratch buffer in CodeCache");
 541       return;
 542     }
 543   }
 544 
 545   // Initialize the relocation buffers
 546   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 547   set_scratch_locs_memory(locs_buf);
 548 }
 549 
 550 
 551 //-----------------------scratch_emit_size-------------------------------------
 552 // Helper function that computes size by emitting code
 553 uint Compile::scratch_emit_size(const Node* n) {
 554   // Start scratch_emit_size section.
 555   set_in_scratch_emit_size(true);
 556 
 557   // Emit into a trash buffer and count bytes emitted.
 558   // This is a pretty expensive way to compute a size,
 559   // but it works well enough if seldom used.
 560   // All common fixed-size instructions are given a size
 561   // method by the AD file.
 562   // Note that the scratch buffer blob and locs memory are
 563   // allocated at the beginning of the compile task, and
 564   // may be shared by several calls to scratch_emit_size.
 565   // The allocation of the scratch buffer blob is particularly
 566   // expensive, since it has to grab the code cache lock.
 567   BufferBlob* blob = this->scratch_buffer_blob();
 568   assert(blob != NULL, "Initialize BufferBlob at start");
 569   assert(blob->size() > MAX_inst_size, "sanity");
 570   relocInfo* locs_buf = scratch_locs_memory();
 571   address blob_begin = blob->content_begin();
 572   address blob_end   = (address)locs_buf;
 573   assert(blob->content_contains(blob_end), "sanity");
 574   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 575   buf.initialize_consts_size(_scratch_const_size);
 576   buf.initialize_stubs_size(MAX_stubs_size);
 577   assert(locs_buf != NULL, "sanity");
 578   int lsize = MAX_locs_size / 3;
 579   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 580   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 581   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 582 
 583   // Do the emission.
 584 
 585   Label fakeL; // Fake label for branch instructions.
 586   Label*   saveL = NULL;
 587   uint save_bnum = 0;
 588   bool is_branch = n->is_MachBranch();
 589   if (is_branch) {
 590     MacroAssembler masm(&buf);
 591     masm.bind(fakeL);
 592     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 593     n->as_MachBranch()->label_set(&fakeL, 0);
 594   }
 595   n->emit(buf, this->regalloc());
 596   if (is_branch) // Restore label.
 597     n->as_MachBranch()->label_set(saveL, save_bnum);
 598 
 599   // End scratch_emit_size section.
 600   set_in_scratch_emit_size(false);
 601 
 602   return buf.insts_size();
 603 }
 604 
 605 
 606 // ============================================================================
 607 //------------------------------Compile standard-------------------------------
 608 debug_only( int Compile::_debug_idx = 100000; )
 609 
 610 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 611 // the continuation bci for on stack replacement.
 612 
 613 
 614 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 615                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
 616                 : Phase(Compiler),
 617                   _env(ci_env),
 618                   _log(ci_env->log()),
 619                   _compile_id(ci_env->compile_id()),
 620                   _save_argument_registers(false),
 621                   _stub_name(NULL),
 622                   _stub_function(NULL),
 623                   _stub_entry_point(NULL),
 624                   _method(target),
 625                   _entry_bci(osr_bci),
 626                   _initial_gvn(NULL),
 627                   _for_igvn(NULL),
 628                   _warm_calls(NULL),
 629                   _subsume_loads(subsume_loads),
 630                   _do_escape_analysis(do_escape_analysis),
 631                   _eliminate_boxing(eliminate_boxing),
 632                   _failure_reason(NULL),
 633                   _code_buffer("Compile::Fill_buffer"),
 634                   _orig_pc_slot(0),
 635                   _orig_pc_slot_offset_in_bytes(0),
 636                   _has_method_handle_invokes(false),
 637                   _mach_constant_base_node(NULL),
 638                   _node_bundling_limit(0),
 639                   _node_bundling_base(NULL),
 640                   _java_calls(0),
 641                   _inner_loops(0),
 642                   _scratch_const_size(-1),
 643                   _in_scratch_emit_size(false),
 644                   _dead_node_list(comp_arena()),
 645                   _dead_node_count(0),
 646 #ifndef PRODUCT
 647                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 648                   _printer(IdealGraphPrinter::printer()),
 649 #endif
 650                   _congraph(NULL),
 651                   _replay_inline_data(NULL),
 652                   _late_inlines(comp_arena(), 2, 0, NULL),
 653                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 654                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 655                   _late_inlines_pos(0),
 656                   _number_of_mh_late_inlines(0),
 657                   _inlining_progress(false),
 658                   _inlining_incrementally(false),
 659                   _print_inlining_list(NULL),
 660                   _print_inlining_idx(0),
 661                   _preserve_jvm_state(0) {
 662   C = this;
 663 
 664   CompileWrapper cw(this);
 665 #ifndef PRODUCT
 666   if (TimeCompiler2) {
 667     tty->print(" ");
 668     target->holder()->name()->print();
 669     tty->print(".");
 670     target->print_short_name();
 671     tty->print("  ");
 672   }
 673   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 674   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 675   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 676   if (!print_opto_assembly) {
 677     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 678     if (print_assembly && !Disassembler::can_decode()) {
 679       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 680       print_opto_assembly = true;
 681     }
 682   }
 683   set_print_assembly(print_opto_assembly);
 684   set_parsed_irreducible_loop(false);
 685 
 686   if (method()->has_option("ReplayInline")) {
 687     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 688   }
 689 #endif
 690   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
 691   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
 692 
 693   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 694     // Make sure the method being compiled gets its own MDO,
 695     // so we can at least track the decompile_count().
 696     // Need MDO to record RTM code generation state.
 697     method()->ensure_method_data();
 698   }
 699 
 700   Init(::AliasLevel);
 701 
 702 
 703   print_compile_messages();
 704 
 705   _ilt = InlineTree::build_inline_tree_root();
 706 
 707   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 708   assert(num_alias_types() >= AliasIdxRaw, "");
 709 
 710 #define MINIMUM_NODE_HASH  1023
 711   // Node list that Iterative GVN will start with
 712   Unique_Node_List for_igvn(comp_arena());
 713   set_for_igvn(&for_igvn);
 714 
 715   // GVN that will be run immediately on new nodes
 716   uint estimated_size = method()->code_size()*4+64;
 717   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 718   PhaseGVN gvn(node_arena(), estimated_size);
 719   set_initial_gvn(&gvn);
 720 
 721   if (print_inlining() || print_intrinsics()) {
 722     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
 723   }
 724   { // Scope for timing the parser
 725     TracePhase t3("parse", &_t_parser, true);
 726 
 727     // Put top into the hash table ASAP.
 728     initial_gvn()->transform_no_reclaim(top());
 729 
 730     // Set up tf(), start(), and find a CallGenerator.
 731     CallGenerator* cg = NULL;
 732     if (is_osr_compilation()) {
 733       const TypeTuple *domain = StartOSRNode::osr_domain();
 734       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 735       init_tf(TypeFunc::make(domain, range));
 736       StartNode* s = new (this) StartOSRNode(root(), domain);
 737       initial_gvn()->set_type_bottom(s);
 738       init_start(s);
 739       cg = CallGenerator::for_osr(method(), entry_bci());
 740     } else {
 741       // Normal case.
 742       init_tf(TypeFunc::make(method()));
 743       StartNode* s = new (this) StartNode(root(), tf()->domain());
 744       initial_gvn()->set_type_bottom(s);
 745       init_start(s);
 746       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 747         // With java.lang.ref.reference.get() we must go through the
 748         // intrinsic when G1 is enabled - even when get() is the root
 749         // method of the compile - so that, if necessary, the value in
 750         // the referent field of the reference object gets recorded by
 751         // the pre-barrier code.
 752         // Specifically, if G1 is enabled, the value in the referent
 753         // field is recorded by the G1 SATB pre barrier. This will
 754         // result in the referent being marked live and the reference
 755         // object removed from the list of discovered references during
 756         // reference processing.
 757         cg = find_intrinsic(method(), false);
 758       }
 759       if (cg == NULL) {
 760         float past_uses = method()->interpreter_invocation_count();
 761         float expected_uses = past_uses;
 762         cg = CallGenerator::for_inline(method(), expected_uses);
 763       }
 764     }
 765     if (failing())  return;
 766     if (cg == NULL) {
 767       record_method_not_compilable_all_tiers("cannot parse method");
 768       return;
 769     }
 770     JVMState* jvms = build_start_state(start(), tf());
 771     if ((jvms = cg->generate(jvms, NULL)) == NULL) {
 772       record_method_not_compilable("method parse failed");
 773       return;
 774     }
 775     GraphKit kit(jvms);
 776 
 777     if (!kit.stopped()) {
 778       // Accept return values, and transfer control we know not where.
 779       // This is done by a special, unique ReturnNode bound to root.
 780       return_values(kit.jvms());
 781     }
 782 
 783     if (kit.has_exceptions()) {
 784       // Any exceptions that escape from this call must be rethrown
 785       // to whatever caller is dynamically above us on the stack.
 786       // This is done by a special, unique RethrowNode bound to root.
 787       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 788     }
 789 
 790     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 791 
 792     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 793       inline_string_calls(true);
 794     }
 795 
 796     if (failing())  return;
 797 
 798     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 799 
 800     // Remove clutter produced by parsing.
 801     if (!failing()) {
 802       ResourceMark rm;
 803       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 804     }
 805   }
 806 
 807   // Note:  Large methods are capped off in do_one_bytecode().
 808   if (failing())  return;
 809 
 810   // After parsing, node notes are no longer automagic.
 811   // They must be propagated by register_new_node_with_optimizer(),
 812   // clone(), or the like.
 813   set_default_node_notes(NULL);
 814 
 815   for (;;) {
 816     int successes = Inline_Warm();
 817     if (failing())  return;
 818     if (successes == 0)  break;
 819   }
 820 
 821   // Drain the list.
 822   Finish_Warm();
 823 #ifndef PRODUCT
 824   if (_printer) {
 825     _printer->print_inlining(this);
 826   }
 827 #endif
 828 
 829   if (failing())  return;
 830   NOT_PRODUCT( verify_graph_edges(); )
 831 
 832   // Now optimize
 833   Optimize();
 834   if (failing())  return;
 835   NOT_PRODUCT( verify_graph_edges(); )
 836 
 837 #ifndef PRODUCT
 838   if (PrintIdeal) {
 839     ttyLocker ttyl;  // keep the following output all in one block
 840     // This output goes directly to the tty, not the compiler log.
 841     // To enable tools to match it up with the compilation activity,
 842     // be sure to tag this tty output with the compile ID.
 843     if (xtty != NULL) {
 844       xtty->head("ideal compile_id='%d'%s", compile_id(),
 845                  is_osr_compilation()    ? " compile_kind='osr'" :
 846                  "");
 847     }
 848     root()->dump(9999);
 849     if (xtty != NULL) {
 850       xtty->tail("ideal");
 851     }
 852   }
 853 #endif
 854 
 855   NOT_PRODUCT( verify_barriers(); )
 856 
 857   // Dump compilation data to replay it.
 858   if (method()->has_option("DumpReplay")) {
 859     env()->dump_replay_data(_compile_id);
 860   }
 861   if (method()->has_option("DumpInline") && (ilt() != NULL)) {
 862     env()->dump_inline_data(_compile_id);
 863   }
 864 
 865   // Now that we know the size of all the monitors we can add a fixed slot
 866   // for the original deopt pc.
 867 
 868   _orig_pc_slot =  fixed_slots();
 869   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 870   set_fixed_slots(next_slot);
 871 
 872   // Now generate code
 873   Code_Gen();
 874   if (failing())  return;
 875 
 876   // Check if we want to skip execution of all compiled code.
 877   {
 878 #ifndef PRODUCT
 879     if (OptoNoExecute) {
 880       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 881       return;
 882     }
 883     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 884 #endif
 885 
 886     if (is_osr_compilation()) {
 887       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 888       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 889     } else {
 890       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 891       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 892     }
 893 
 894     env()->register_method(_method, _entry_bci,
 895                            &_code_offsets,
 896                            _orig_pc_slot_offset_in_bytes,
 897                            code_buffer(),
 898                            frame_size_in_words(), _oop_map_set,
 899                            &_handler_table, &_inc_table,
 900                            compiler,
 901                            env()->comp_level(),
 902                            has_unsafe_access(),
 903                            SharedRuntime::is_wide_vector(max_vector_size()),
 904                            rtm_state()
 905                            );
 906 
 907     if (log() != NULL) // Print code cache state into compiler log
 908       log()->code_cache_state();
 909   }
 910 }
 911 
 912 //------------------------------Compile----------------------------------------
 913 // Compile a runtime stub
 914 Compile::Compile( ciEnv* ci_env,
 915                   TypeFunc_generator generator,
 916                   address stub_function,
 917                   const char *stub_name,
 918                   int is_fancy_jump,
 919                   bool pass_tls,
 920                   bool save_arg_registers,
 921                   bool return_pc )
 922   : Phase(Compiler),
 923     _env(ci_env),
 924     _log(ci_env->log()),
 925     _compile_id(0),
 926     _save_argument_registers(save_arg_registers),
 927     _method(NULL),
 928     _stub_name(stub_name),
 929     _stub_function(stub_function),
 930     _stub_entry_point(NULL),
 931     _entry_bci(InvocationEntryBci),
 932     _initial_gvn(NULL),
 933     _for_igvn(NULL),
 934     _warm_calls(NULL),
 935     _orig_pc_slot(0),
 936     _orig_pc_slot_offset_in_bytes(0),
 937     _subsume_loads(true),
 938     _do_escape_analysis(false),
 939     _eliminate_boxing(false),
 940     _failure_reason(NULL),
 941     _code_buffer("Compile::Fill_buffer"),
 942     _has_method_handle_invokes(false),
 943     _mach_constant_base_node(NULL),
 944     _node_bundling_limit(0),
 945     _node_bundling_base(NULL),
 946     _java_calls(0),
 947     _inner_loops(0),
 948 #ifndef PRODUCT
 949     _trace_opto_output(TraceOptoOutput),
 950     _printer(NULL),
 951 #endif
 952     _dead_node_list(comp_arena()),
 953     _dead_node_count(0),
 954     _congraph(NULL),
 955     _replay_inline_data(NULL),
 956     _number_of_mh_late_inlines(0),
 957     _inlining_progress(false),
 958     _inlining_incrementally(false),
 959     _print_inlining_list(NULL),
 960     _print_inlining_idx(0),
 961     _preserve_jvm_state(0) {
 962   C = this;
 963 
 964 #ifndef PRODUCT
 965   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 966   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
 967   set_print_assembly(PrintFrameConverterAssembly);
 968   set_parsed_irreducible_loop(false);
 969 #endif
 970   CompileWrapper cw(this);
 971   Init(/*AliasLevel=*/ 0);
 972   init_tf((*generator)());
 973 
 974   {
 975     // The following is a dummy for the sake of GraphKit::gen_stub
 976     Unique_Node_List for_igvn(comp_arena());
 977     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
 978     PhaseGVN gvn(Thread::current()->resource_area(),255);
 979     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
 980     gvn.transform_no_reclaim(top());
 981 
 982     GraphKit kit;
 983     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
 984   }
 985 
 986   NOT_PRODUCT( verify_graph_edges(); )
 987   Code_Gen();
 988   if (failing())  return;
 989 
 990 
 991   // Entry point will be accessed using compile->stub_entry_point();
 992   if (code_buffer() == NULL) {
 993     Matcher::soft_match_failure();
 994   } else {
 995     if (PrintAssembly && (WizardMode || Verbose))
 996       tty->print_cr("### Stub::%s", stub_name);
 997 
 998     if (!failing()) {
 999       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1000 
1001       // Make the NMethod
1002       // For now we mark the frame as never safe for profile stackwalking
1003       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1004                                                       code_buffer(),
1005                                                       CodeOffsets::frame_never_safe,
1006                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1007                                                       frame_size_in_words(),
1008                                                       _oop_map_set,
1009                                                       save_arg_registers);
1010       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1011 
1012       _stub_entry_point = rs->entry_point();
1013     }
1014   }
1015 }
1016 
1017 //------------------------------Init-------------------------------------------
1018 // Prepare for a single compilation
1019 void Compile::Init(int aliaslevel) {
1020   _unique  = 0;
1021   _regalloc = NULL;
1022 
1023   _tf      = NULL;  // filled in later
1024   _top     = NULL;  // cached later
1025   _matcher = NULL;  // filled in later
1026   _cfg     = NULL;  // filled in later
1027 
1028   set_24_bit_selection_and_mode(Use24BitFP, false);
1029 
1030   _node_note_array = NULL;
1031   _default_node_notes = NULL;
1032 
1033   _immutable_memory = NULL; // filled in at first inquiry
1034 
1035   // Globally visible Nodes
1036   // First set TOP to NULL to give safe behavior during creation of RootNode
1037   set_cached_top_node(NULL);
1038   set_root(new (this) RootNode());
1039   // Now that you have a Root to point to, create the real TOP
1040   set_cached_top_node( new (this) ConNode(Type::TOP) );
1041   set_recent_alloc(NULL, NULL);
1042 
1043   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1044   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1045   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1046   env()->set_dependencies(new Dependencies(env()));
1047 
1048   _fixed_slots = 0;
1049   set_has_split_ifs(false);
1050   set_has_loops(has_method() && method()->has_loops()); // first approximation
1051   set_has_stringbuilder(false);
1052   set_has_boxed_value(false);
1053   _trap_can_recompile = false;  // no traps emitted yet
1054   _major_progress = true; // start out assuming good things will happen
1055   set_has_unsafe_access(false);
1056   set_max_vector_size(0);
1057   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1058   set_decompile_count(0);
1059 
1060   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1061   set_num_loop_opts(LoopOptsCount);
1062   set_do_inlining(Inline);
1063   set_max_inline_size(MaxInlineSize);
1064   set_freq_inline_size(FreqInlineSize);
1065   set_do_scheduling(OptoScheduling);
1066   set_do_count_invocations(false);
1067   set_do_method_data_update(false);
1068   set_rtm_state(NoRTM); // No RTM lock eliding by default
1069 #if INCLUDE_RTM_OPT
1070   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1071     int rtm_state = method()->method_data()->rtm_state();
1072     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1073       // Don't generate RTM lock eliding code.
1074       set_rtm_state(NoRTM);
1075     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1076       // Generate RTM lock eliding code without abort ratio calculation code.
1077       set_rtm_state(UseRTM);
1078     } else if (UseRTMDeopt) {
1079       // Generate RTM lock eliding code and include abort ratio calculation
1080       // code if UseRTMDeopt is on.
1081       set_rtm_state(ProfileRTM);
1082     }
1083   }
1084 #endif
1085   if (debug_info()->recording_non_safepoints()) {
1086     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1087                         (comp_arena(), 8, 0, NULL));
1088     set_default_node_notes(Node_Notes::make(this));
1089   }
1090 
1091   // // -- Initialize types before each compile --
1092   // // Update cached type information
1093   // if( _method && _method->constants() )
1094   //   Type::update_loaded_types(_method, _method->constants());
1095 
1096   // Init alias_type map.
1097   if (!_do_escape_analysis && aliaslevel == 3)
1098     aliaslevel = 2;  // No unique types without escape analysis
1099   _AliasLevel = aliaslevel;
1100   const int grow_ats = 16;
1101   _max_alias_types = grow_ats;
1102   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1103   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1104   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1105   {
1106     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1107   }
1108   // Initialize the first few types.
1109   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1110   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1111   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1112   _num_alias_types = AliasIdxRaw+1;
1113   // Zero out the alias type cache.
1114   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1115   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1116   probe_alias_cache(NULL)->_index = AliasIdxTop;
1117 
1118   _intrinsics = NULL;
1119   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1120   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1121   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1122   register_library_intrinsics();
1123 }
1124 
1125 //---------------------------init_start----------------------------------------
1126 // Install the StartNode on this compile object.
1127 void Compile::init_start(StartNode* s) {
1128   if (failing())
1129     return; // already failing
1130   assert(s == start(), "");
1131 }
1132 
1133 StartNode* Compile::start() const {
1134   assert(!failing(), "");
1135   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1136     Node* start = root()->fast_out(i);
1137     if( start->is_Start() )
1138       return start->as_Start();
1139   }
1140   ShouldNotReachHere();
1141   return NULL;
1142 }
1143 
1144 //-------------------------------immutable_memory-------------------------------------
1145 // Access immutable memory
1146 Node* Compile::immutable_memory() {
1147   if (_immutable_memory != NULL) {
1148     return _immutable_memory;
1149   }
1150   StartNode* s = start();
1151   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1152     Node *p = s->fast_out(i);
1153     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1154       _immutable_memory = p;
1155       return _immutable_memory;
1156     }
1157   }
1158   ShouldNotReachHere();
1159   return NULL;
1160 }
1161 
1162 //----------------------set_cached_top_node------------------------------------
1163 // Install the cached top node, and make sure Node::is_top works correctly.
1164 void Compile::set_cached_top_node(Node* tn) {
1165   if (tn != NULL)  verify_top(tn);
1166   Node* old_top = _top;
1167   _top = tn;
1168   // Calling Node::setup_is_top allows the nodes the chance to adjust
1169   // their _out arrays.
1170   if (_top != NULL)     _top->setup_is_top();
1171   if (old_top != NULL)  old_top->setup_is_top();
1172   assert(_top == NULL || top()->is_top(), "");
1173 }
1174 
1175 #ifdef ASSERT
1176 uint Compile::count_live_nodes_by_graph_walk() {
1177   Unique_Node_List useful(comp_arena());
1178   // Get useful node list by walking the graph.
1179   identify_useful_nodes(useful);
1180   return useful.size();
1181 }
1182 
1183 void Compile::print_missing_nodes() {
1184 
1185   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1186   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1187     return;
1188   }
1189 
1190   // This is an expensive function. It is executed only when the user
1191   // specifies VerifyIdealNodeCount option or otherwise knows the
1192   // additional work that needs to be done to identify reachable nodes
1193   // by walking the flow graph and find the missing ones using
1194   // _dead_node_list.
1195 
1196   Unique_Node_List useful(comp_arena());
1197   // Get useful node list by walking the graph.
1198   identify_useful_nodes(useful);
1199 
1200   uint l_nodes = C->live_nodes();
1201   uint l_nodes_by_walk = useful.size();
1202 
1203   if (l_nodes != l_nodes_by_walk) {
1204     if (_log != NULL) {
1205       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1206       _log->stamp();
1207       _log->end_head();
1208     }
1209     VectorSet& useful_member_set = useful.member_set();
1210     int last_idx = l_nodes_by_walk;
1211     for (int i = 0; i < last_idx; i++) {
1212       if (useful_member_set.test(i)) {
1213         if (_dead_node_list.test(i)) {
1214           if (_log != NULL) {
1215             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1216           }
1217           if (PrintIdealNodeCount) {
1218             // Print the log message to tty
1219               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1220               useful.at(i)->dump();
1221           }
1222         }
1223       }
1224       else if (! _dead_node_list.test(i)) {
1225         if (_log != NULL) {
1226           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1227         }
1228         if (PrintIdealNodeCount) {
1229           // Print the log message to tty
1230           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1231         }
1232       }
1233     }
1234     if (_log != NULL) {
1235       _log->tail("mismatched_nodes");
1236     }
1237   }
1238 }
1239 #endif
1240 
1241 #ifndef PRODUCT
1242 void Compile::verify_top(Node* tn) const {
1243   if (tn != NULL) {
1244     assert(tn->is_Con(), "top node must be a constant");
1245     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1246     assert(tn->in(0) != NULL, "must have live top node");
1247   }
1248 }
1249 #endif
1250 
1251 
1252 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1253 
1254 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1255   guarantee(arr != NULL, "");
1256   int num_blocks = arr->length();
1257   if (grow_by < num_blocks)  grow_by = num_blocks;
1258   int num_notes = grow_by * _node_notes_block_size;
1259   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1260   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1261   while (num_notes > 0) {
1262     arr->append(notes);
1263     notes     += _node_notes_block_size;
1264     num_notes -= _node_notes_block_size;
1265   }
1266   assert(num_notes == 0, "exact multiple, please");
1267 }
1268 
1269 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1270   if (source == NULL || dest == NULL)  return false;
1271 
1272   if (dest->is_Con())
1273     return false;               // Do not push debug info onto constants.
1274 
1275 #ifdef ASSERT
1276   // Leave a bread crumb trail pointing to the original node:
1277   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1278     dest->set_debug_orig(source);
1279   }
1280 #endif
1281 
1282   if (node_note_array() == NULL)
1283     return false;               // Not collecting any notes now.
1284 
1285   // This is a copy onto a pre-existing node, which may already have notes.
1286   // If both nodes have notes, do not overwrite any pre-existing notes.
1287   Node_Notes* source_notes = node_notes_at(source->_idx);
1288   if (source_notes == NULL || source_notes->is_clear())  return false;
1289   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1290   if (dest_notes == NULL || dest_notes->is_clear()) {
1291     return set_node_notes_at(dest->_idx, source_notes);
1292   }
1293 
1294   Node_Notes merged_notes = (*source_notes);
1295   // The order of operations here ensures that dest notes will win...
1296   merged_notes.update_from(dest_notes);
1297   return set_node_notes_at(dest->_idx, &merged_notes);
1298 }
1299 
1300 
1301 //--------------------------allow_range_check_smearing-------------------------
1302 // Gating condition for coalescing similar range checks.
1303 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1304 // single covering check that is at least as strong as any of them.
1305 // If the optimization succeeds, the simplified (strengthened) range check
1306 // will always succeed.  If it fails, we will deopt, and then give up
1307 // on the optimization.
1308 bool Compile::allow_range_check_smearing() const {
1309   // If this method has already thrown a range-check,
1310   // assume it was because we already tried range smearing
1311   // and it failed.
1312   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1313   return !already_trapped;
1314 }
1315 
1316 
1317 //------------------------------flatten_alias_type-----------------------------
1318 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1319   int offset = tj->offset();
1320   TypePtr::PTR ptr = tj->ptr();
1321 
1322   // Known instance (scalarizable allocation) alias only with itself.
1323   bool is_known_inst = tj->isa_oopptr() != NULL &&
1324                        tj->is_oopptr()->is_known_instance();
1325 
1326   // Process weird unsafe references.
1327   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1328     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1329     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1330     tj = TypeOopPtr::BOTTOM;
1331     ptr = tj->ptr();
1332     offset = tj->offset();
1333   }
1334 
1335   // Array pointers need some flattening
1336   const TypeAryPtr *ta = tj->isa_aryptr();
1337   if (ta && ta->is_stable()) {
1338     // Erase stability property for alias analysis.
1339     tj = ta = ta->cast_to_stable(false);
1340   }
1341   if( ta && is_known_inst ) {
1342     if ( offset != Type::OffsetBot &&
1343          offset > arrayOopDesc::length_offset_in_bytes() ) {
1344       offset = Type::OffsetBot; // Flatten constant access into array body only
1345       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1346     }
1347   } else if( ta && _AliasLevel >= 2 ) {
1348     // For arrays indexed by constant indices, we flatten the alias
1349     // space to include all of the array body.  Only the header, klass
1350     // and array length can be accessed un-aliased.
1351     if( offset != Type::OffsetBot ) {
1352       if( ta->const_oop() ) { // MethodData* or Method*
1353         offset = Type::OffsetBot;   // Flatten constant access into array body
1354         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1355       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1356         // range is OK as-is.
1357         tj = ta = TypeAryPtr::RANGE;
1358       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1359         tj = TypeInstPtr::KLASS; // all klass loads look alike
1360         ta = TypeAryPtr::RANGE; // generic ignored junk
1361         ptr = TypePtr::BotPTR;
1362       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1363         tj = TypeInstPtr::MARK;
1364         ta = TypeAryPtr::RANGE; // generic ignored junk
1365         ptr = TypePtr::BotPTR;
1366       } else {                  // Random constant offset into array body
1367         offset = Type::OffsetBot;   // Flatten constant access into array body
1368         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1369       }
1370     }
1371     // Arrays of fixed size alias with arrays of unknown size.
1372     if (ta->size() != TypeInt::POS) {
1373       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1374       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1375     }
1376     // Arrays of known objects become arrays of unknown objects.
1377     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1378       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1379       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1380     }
1381     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1382       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1383       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1384     }
1385     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1386     // cannot be distinguished by bytecode alone.
1387     if (ta->elem() == TypeInt::BOOL) {
1388       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1389       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1390       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1391     }
1392     // During the 2nd round of IterGVN, NotNull castings are removed.
1393     // Make sure the Bottom and NotNull variants alias the same.
1394     // Also, make sure exact and non-exact variants alias the same.
1395     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1396       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1397     }
1398   }
1399 
1400   // Oop pointers need some flattening
1401   const TypeInstPtr *to = tj->isa_instptr();
1402   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1403     ciInstanceKlass *k = to->klass()->as_instance_klass();
1404     if( ptr == TypePtr::Constant ) {
1405       if (to->klass() != ciEnv::current()->Class_klass() ||
1406           offset < k->size_helper() * wordSize) {
1407         // No constant oop pointers (such as Strings); they alias with
1408         // unknown strings.
1409         assert(!is_known_inst, "not scalarizable allocation");
1410         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1411       }
1412     } else if( is_known_inst ) {
1413       tj = to; // Keep NotNull and klass_is_exact for instance type
1414     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1415       // During the 2nd round of IterGVN, NotNull castings are removed.
1416       // Make sure the Bottom and NotNull variants alias the same.
1417       // Also, make sure exact and non-exact variants alias the same.
1418       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1419     }
1420     if (to->speculative() != NULL) {
1421       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1422     }
1423     // Canonicalize the holder of this field
1424     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1425       // First handle header references such as a LoadKlassNode, even if the
1426       // object's klass is unloaded at compile time (4965979).
1427       if (!is_known_inst) { // Do it only for non-instance types
1428         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1429       }
1430     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1431       // Static fields are in the space above the normal instance
1432       // fields in the java.lang.Class instance.
1433       if (to->klass() != ciEnv::current()->Class_klass()) {
1434         to = NULL;
1435         tj = TypeOopPtr::BOTTOM;
1436         offset = tj->offset();
1437       }
1438     } else {
1439       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1440       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1441         if( is_known_inst ) {
1442           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1443         } else {
1444           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1445         }
1446       }
1447     }
1448   }
1449 
1450   // Klass pointers to object array klasses need some flattening
1451   const TypeKlassPtr *tk = tj->isa_klassptr();
1452   if( tk ) {
1453     // If we are referencing a field within a Klass, we need
1454     // to assume the worst case of an Object.  Both exact and
1455     // inexact types must flatten to the same alias class so
1456     // use NotNull as the PTR.
1457     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1458 
1459       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1460                                    TypeKlassPtr::OBJECT->klass(),
1461                                    offset);
1462     }
1463 
1464     ciKlass* klass = tk->klass();
1465     if( klass->is_obj_array_klass() ) {
1466       ciKlass* k = TypeAryPtr::OOPS->klass();
1467       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1468         k = TypeInstPtr::BOTTOM->klass();
1469       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1470     }
1471 
1472     // Check for precise loads from the primary supertype array and force them
1473     // to the supertype cache alias index.  Check for generic array loads from
1474     // the primary supertype array and also force them to the supertype cache
1475     // alias index.  Since the same load can reach both, we need to merge
1476     // these 2 disparate memories into the same alias class.  Since the
1477     // primary supertype array is read-only, there's no chance of confusion
1478     // where we bypass an array load and an array store.
1479     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1480     if (offset == Type::OffsetBot ||
1481         (offset >= primary_supers_offset &&
1482          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1483         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1484       offset = in_bytes(Klass::secondary_super_cache_offset());
1485       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1486     }
1487   }
1488 
1489   // Flatten all Raw pointers together.
1490   if (tj->base() == Type::RawPtr)
1491     tj = TypeRawPtr::BOTTOM;
1492 
1493   if (tj->base() == Type::AnyPtr)
1494     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1495 
1496   // Flatten all to bottom for now
1497   switch( _AliasLevel ) {
1498   case 0:
1499     tj = TypePtr::BOTTOM;
1500     break;
1501   case 1:                       // Flatten to: oop, static, field or array
1502     switch (tj->base()) {
1503     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1504     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1505     case Type::AryPtr:   // do not distinguish arrays at all
1506     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1507     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1508     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1509     default: ShouldNotReachHere();
1510     }
1511     break;
1512   case 2:                       // No collapsing at level 2; keep all splits
1513   case 3:                       // No collapsing at level 3; keep all splits
1514     break;
1515   default:
1516     Unimplemented();
1517   }
1518 
1519   offset = tj->offset();
1520   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1521 
1522   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1523           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1524           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1525           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1526           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1527           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1528           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1529           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1530   assert( tj->ptr() != TypePtr::TopPTR &&
1531           tj->ptr() != TypePtr::AnyNull &&
1532           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1533 //    assert( tj->ptr() != TypePtr::Constant ||
1534 //            tj->base() == Type::RawPtr ||
1535 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1536 
1537   return tj;
1538 }
1539 
1540 void Compile::AliasType::Init(int i, const TypePtr* at) {
1541   _index = i;
1542   _adr_type = at;
1543   _field = NULL;
1544   _element = NULL;
1545   _is_rewritable = true; // default
1546   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1547   if (atoop != NULL && atoop->is_known_instance()) {
1548     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1549     _general_index = Compile::current()->get_alias_index(gt);
1550   } else {
1551     _general_index = 0;
1552   }
1553 }
1554 
1555 //---------------------------------print_on------------------------------------
1556 #ifndef PRODUCT
1557 void Compile::AliasType::print_on(outputStream* st) {
1558   if (index() < 10)
1559         st->print("@ <%d> ", index());
1560   else  st->print("@ <%d>",  index());
1561   st->print(is_rewritable() ? "   " : " RO");
1562   int offset = adr_type()->offset();
1563   if (offset == Type::OffsetBot)
1564         st->print(" +any");
1565   else  st->print(" +%-3d", offset);
1566   st->print(" in ");
1567   adr_type()->dump_on(st);
1568   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1569   if (field() != NULL && tjp) {
1570     if (tjp->klass()  != field()->holder() ||
1571         tjp->offset() != field()->offset_in_bytes()) {
1572       st->print(" != ");
1573       field()->print();
1574       st->print(" ***");
1575     }
1576   }
1577 }
1578 
1579 void print_alias_types() {
1580   Compile* C = Compile::current();
1581   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1582   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1583     C->alias_type(idx)->print_on(tty);
1584     tty->cr();
1585   }
1586 }
1587 #endif
1588 
1589 
1590 //----------------------------probe_alias_cache--------------------------------
1591 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1592   intptr_t key = (intptr_t) adr_type;
1593   key ^= key >> logAliasCacheSize;
1594   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1595 }
1596 
1597 
1598 //-----------------------------grow_alias_types--------------------------------
1599 void Compile::grow_alias_types() {
1600   const int old_ats  = _max_alias_types; // how many before?
1601   const int new_ats  = old_ats;          // how many more?
1602   const int grow_ats = old_ats+new_ats;  // how many now?
1603   _max_alias_types = grow_ats;
1604   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1605   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1606   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1607   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1608 }
1609 
1610 
1611 //--------------------------------find_alias_type------------------------------
1612 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1613   if (_AliasLevel == 0)
1614     return alias_type(AliasIdxBot);
1615 
1616   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1617   if (ace->_adr_type == adr_type) {
1618     return alias_type(ace->_index);
1619   }
1620 
1621   // Handle special cases.
1622   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1623   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1624 
1625   // Do it the slow way.
1626   const TypePtr* flat = flatten_alias_type(adr_type);
1627 
1628 #ifdef ASSERT
1629   assert(flat == flatten_alias_type(flat), "idempotent");
1630   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1631   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1632     const TypeOopPtr* foop = flat->is_oopptr();
1633     // Scalarizable allocations have exact klass always.
1634     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1635     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1636     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1637   }
1638   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1639 #endif
1640 
1641   int idx = AliasIdxTop;
1642   for (int i = 0; i < num_alias_types(); i++) {
1643     if (alias_type(i)->adr_type() == flat) {
1644       idx = i;
1645       break;
1646     }
1647   }
1648 
1649   if (idx == AliasIdxTop) {
1650     if (no_create)  return NULL;
1651     // Grow the array if necessary.
1652     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1653     // Add a new alias type.
1654     idx = _num_alias_types++;
1655     _alias_types[idx]->Init(idx, flat);
1656     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1657     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1658     if (flat->isa_instptr()) {
1659       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1660           && flat->is_instptr()->klass() == env()->Class_klass())
1661         alias_type(idx)->set_rewritable(false);
1662     }
1663     if (flat->isa_aryptr()) {
1664 #ifdef ASSERT
1665       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1666       // (T_BYTE has the weakest alignment and size restrictions...)
1667       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1668 #endif
1669       if (flat->offset() == TypePtr::OffsetBot) {
1670         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1671       }
1672     }
1673     if (flat->isa_klassptr()) {
1674       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1675         alias_type(idx)->set_rewritable(false);
1676       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1677         alias_type(idx)->set_rewritable(false);
1678       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1679         alias_type(idx)->set_rewritable(false);
1680       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1681         alias_type(idx)->set_rewritable(false);
1682     }
1683     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1684     // but the base pointer type is not distinctive enough to identify
1685     // references into JavaThread.)
1686 
1687     // Check for final fields.
1688     const TypeInstPtr* tinst = flat->isa_instptr();
1689     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1690       ciField* field;
1691       if (tinst->const_oop() != NULL &&
1692           tinst->klass() == ciEnv::current()->Class_klass() &&
1693           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1694         // static field
1695         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1696         field = k->get_field_by_offset(tinst->offset(), true);
1697       } else {
1698         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1699         field = k->get_field_by_offset(tinst->offset(), false);
1700       }
1701       assert(field == NULL ||
1702              original_field == NULL ||
1703              (field->holder() == original_field->holder() &&
1704               field->offset() == original_field->offset() &&
1705               field->is_static() == original_field->is_static()), "wrong field?");
1706       // Set field() and is_rewritable() attributes.
1707       if (field != NULL)  alias_type(idx)->set_field(field);
1708     }
1709   }
1710 
1711   // Fill the cache for next time.
1712   ace->_adr_type = adr_type;
1713   ace->_index    = idx;
1714   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1715 
1716   // Might as well try to fill the cache for the flattened version, too.
1717   AliasCacheEntry* face = probe_alias_cache(flat);
1718   if (face->_adr_type == NULL) {
1719     face->_adr_type = flat;
1720     face->_index    = idx;
1721     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1722   }
1723 
1724   return alias_type(idx);
1725 }
1726 
1727 
1728 Compile::AliasType* Compile::alias_type(ciField* field) {
1729   const TypeOopPtr* t;
1730   if (field->is_static())
1731     t = TypeInstPtr::make(field->holder()->java_mirror());
1732   else
1733     t = TypeOopPtr::make_from_klass_raw(field->holder());
1734   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1735   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1736   return atp;
1737 }
1738 
1739 
1740 //------------------------------have_alias_type--------------------------------
1741 bool Compile::have_alias_type(const TypePtr* adr_type) {
1742   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1743   if (ace->_adr_type == adr_type) {
1744     return true;
1745   }
1746 
1747   // Handle special cases.
1748   if (adr_type == NULL)             return true;
1749   if (adr_type == TypePtr::BOTTOM)  return true;
1750 
1751   return find_alias_type(adr_type, true, NULL) != NULL;
1752 }
1753 
1754 //-----------------------------must_alias--------------------------------------
1755 // True if all values of the given address type are in the given alias category.
1756 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1757   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1758   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1759   if (alias_idx == AliasIdxTop)         return false; // the empty category
1760   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1761 
1762   // the only remaining possible overlap is identity
1763   int adr_idx = get_alias_index(adr_type);
1764   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1765   assert(adr_idx == alias_idx ||
1766          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1767           && adr_type                       != TypeOopPtr::BOTTOM),
1768          "should not be testing for overlap with an unsafe pointer");
1769   return adr_idx == alias_idx;
1770 }
1771 
1772 //------------------------------can_alias--------------------------------------
1773 // True if any values of the given address type are in the given alias category.
1774 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1775   if (alias_idx == AliasIdxTop)         return false; // the empty category
1776   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1777   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1778   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1779 
1780   // the only remaining possible overlap is identity
1781   int adr_idx = get_alias_index(adr_type);
1782   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1783   return adr_idx == alias_idx;
1784 }
1785 
1786 
1787 
1788 //---------------------------pop_warm_call-------------------------------------
1789 WarmCallInfo* Compile::pop_warm_call() {
1790   WarmCallInfo* wci = _warm_calls;
1791   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1792   return wci;
1793 }
1794 
1795 //----------------------------Inline_Warm--------------------------------------
1796 int Compile::Inline_Warm() {
1797   // If there is room, try to inline some more warm call sites.
1798   // %%% Do a graph index compaction pass when we think we're out of space?
1799   if (!InlineWarmCalls)  return 0;
1800 
1801   int calls_made_hot = 0;
1802   int room_to_grow   = NodeCountInliningCutoff - unique();
1803   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1804   int amount_grown   = 0;
1805   WarmCallInfo* call;
1806   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1807     int est_size = (int)call->size();
1808     if (est_size > (room_to_grow - amount_grown)) {
1809       // This one won't fit anyway.  Get rid of it.
1810       call->make_cold();
1811       continue;
1812     }
1813     call->make_hot();
1814     calls_made_hot++;
1815     amount_grown   += est_size;
1816     amount_to_grow -= est_size;
1817   }
1818 
1819   if (calls_made_hot > 0)  set_major_progress();
1820   return calls_made_hot;
1821 }
1822 
1823 
1824 //----------------------------Finish_Warm--------------------------------------
1825 void Compile::Finish_Warm() {
1826   if (!InlineWarmCalls)  return;
1827   if (failing())  return;
1828   if (warm_calls() == NULL)  return;
1829 
1830   // Clean up loose ends, if we are out of space for inlining.
1831   WarmCallInfo* call;
1832   while ((call = pop_warm_call()) != NULL) {
1833     call->make_cold();
1834   }
1835 }
1836 
1837 //---------------------cleanup_loop_predicates-----------------------
1838 // Remove the opaque nodes that protect the predicates so that all unused
1839 // checks and uncommon_traps will be eliminated from the ideal graph
1840 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1841   if (predicate_count()==0) return;
1842   for (int i = predicate_count(); i > 0; i--) {
1843     Node * n = predicate_opaque1_node(i-1);
1844     assert(n->Opcode() == Op_Opaque1, "must be");
1845     igvn.replace_node(n, n->in(1));
1846   }
1847   assert(predicate_count()==0, "should be clean!");
1848 }
1849 
1850 // StringOpts and late inlining of string methods
1851 void Compile::inline_string_calls(bool parse_time) {
1852   {
1853     // remove useless nodes to make the usage analysis simpler
1854     ResourceMark rm;
1855     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1856   }
1857 
1858   {
1859     ResourceMark rm;
1860     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1861     PhaseStringOpts pso(initial_gvn(), for_igvn());
1862     print_method(PHASE_AFTER_STRINGOPTS, 3);
1863   }
1864 
1865   // now inline anything that we skipped the first time around
1866   if (!parse_time) {
1867     _late_inlines_pos = _late_inlines.length();
1868   }
1869 
1870   while (_string_late_inlines.length() > 0) {
1871     CallGenerator* cg = _string_late_inlines.pop();
1872     cg->do_late_inline();
1873     if (failing())  return;
1874   }
1875   _string_late_inlines.trunc_to(0);
1876 }
1877 
1878 // Late inlining of boxing methods
1879 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1880   if (_boxing_late_inlines.length() > 0) {
1881     assert(has_boxed_value(), "inconsistent");
1882 
1883     PhaseGVN* gvn = initial_gvn();
1884     set_inlining_incrementally(true);
1885 
1886     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1887     for_igvn()->clear();
1888     gvn->replace_with(&igvn);
1889 
1890     while (_boxing_late_inlines.length() > 0) {
1891       CallGenerator* cg = _boxing_late_inlines.pop();
1892       cg->do_late_inline();
1893       if (failing())  return;
1894     }
1895     _boxing_late_inlines.trunc_to(0);
1896 
1897     {
1898       ResourceMark rm;
1899       PhaseRemoveUseless pru(gvn, for_igvn());
1900     }
1901 
1902     igvn = PhaseIterGVN(gvn);
1903     igvn.optimize();
1904 
1905     set_inlining_progress(false);
1906     set_inlining_incrementally(false);
1907   }
1908 }
1909 
1910 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1911   assert(IncrementalInline, "incremental inlining should be on");
1912   PhaseGVN* gvn = initial_gvn();
1913 
1914   set_inlining_progress(false);
1915   for_igvn()->clear();
1916   gvn->replace_with(&igvn);
1917 
1918   int i = 0;
1919 
1920   for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1921     CallGenerator* cg = _late_inlines.at(i);
1922     _late_inlines_pos = i+1;
1923     cg->do_late_inline();
1924     if (failing())  return;
1925   }
1926   int j = 0;
1927   for (; i < _late_inlines.length(); i++, j++) {
1928     _late_inlines.at_put(j, _late_inlines.at(i));
1929   }
1930   _late_inlines.trunc_to(j);
1931 
1932   {
1933     ResourceMark rm;
1934     PhaseRemoveUseless pru(gvn, for_igvn());
1935   }
1936 
1937   igvn = PhaseIterGVN(gvn);
1938 }
1939 
1940 // Perform incremental inlining until bound on number of live nodes is reached
1941 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1942   PhaseGVN* gvn = initial_gvn();
1943 
1944   set_inlining_incrementally(true);
1945   set_inlining_progress(true);
1946   uint low_live_nodes = 0;
1947 
1948   while(inlining_progress() && _late_inlines.length() > 0) {
1949 
1950     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1951       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
1952         // PhaseIdealLoop is expensive so we only try it once we are
1953         // out of loop and we only try it again if the previous helped
1954         // got the number of nodes down significantly
1955         PhaseIdealLoop ideal_loop( igvn, false, true );
1956         if (failing())  return;
1957         low_live_nodes = live_nodes();
1958         _major_progress = true;
1959       }
1960 
1961       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1962         break;
1963       }
1964     }
1965 
1966     inline_incrementally_one(igvn);
1967 
1968     if (failing())  return;
1969 
1970     igvn.optimize();
1971 
1972     if (failing())  return;
1973   }
1974 
1975   assert( igvn._worklist.size() == 0, "should be done with igvn" );
1976 
1977   if (_string_late_inlines.length() > 0) {
1978     assert(has_stringbuilder(), "inconsistent");
1979     for_igvn()->clear();
1980     initial_gvn()->replace_with(&igvn);
1981 
1982     inline_string_calls(false);
1983 
1984     if (failing())  return;
1985 
1986     {
1987       ResourceMark rm;
1988       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1989     }
1990 
1991     igvn = PhaseIterGVN(gvn);
1992 
1993     igvn.optimize();
1994   }
1995 
1996   set_inlining_incrementally(false);
1997 }
1998 
1999 
2000 //------------------------------Optimize---------------------------------------
2001 // Given a graph, optimize it.
2002 void Compile::Optimize() {
2003   TracePhase t1("optimizer", &_t_optimizer, true);
2004 
2005 #ifndef PRODUCT
2006   if (env()->break_at_compile()) {
2007     BREAKPOINT;
2008   }
2009 
2010 #endif
2011 
2012   ResourceMark rm;
2013   int          loop_opts_cnt;
2014 
2015   NOT_PRODUCT( verify_graph_edges(); )
2016 
2017   print_method(PHASE_AFTER_PARSING);
2018 
2019  {
2020   // Iterative Global Value Numbering, including ideal transforms
2021   // Initialize IterGVN with types and values from parse-time GVN
2022   PhaseIterGVN igvn(initial_gvn());
2023   {
2024     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2025     igvn.optimize();
2026   }
2027 
2028   print_method(PHASE_ITER_GVN1, 2);
2029 
2030   if (failing())  return;
2031 
2032   {
2033     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2034     inline_incrementally(igvn);
2035   }
2036 
2037   print_method(PHASE_INCREMENTAL_INLINE, 2);
2038 
2039   if (failing())  return;
2040 
2041   if (eliminate_boxing()) {
2042     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2043     // Inline valueOf() methods now.
2044     inline_boxing_calls(igvn);
2045 
2046     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2047 
2048     if (failing())  return;
2049   }
2050 
2051   // Remove the speculative part of types and clean up the graph from
2052   // the extra CastPP nodes whose only purpose is to carry them. Do
2053   // that early so that optimizations are not disrupted by the extra
2054   // CastPP nodes.
2055   remove_speculative_types(igvn);
2056 
2057   // No more new expensive nodes will be added to the list from here
2058   // so keep only the actual candidates for optimizations.
2059   cleanup_expensive_nodes(igvn);
2060 
2061   // Perform escape analysis
2062   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2063     if (has_loops()) {
2064       // Cleanup graph (remove dead nodes).
2065       TracePhase t2("idealLoop", &_t_idealLoop, true);
2066       PhaseIdealLoop ideal_loop( igvn, false, true );
2067       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2068       if (failing())  return;
2069     }
2070     ConnectionGraph::do_analysis(this, &igvn);
2071 
2072     if (failing())  return;
2073 
2074     // Optimize out fields loads from scalar replaceable allocations.
2075     igvn.optimize();
2076     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2077 
2078     if (failing())  return;
2079 
2080     if (congraph() != NULL && macro_count() > 0) {
2081       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2082       PhaseMacroExpand mexp(igvn);
2083       mexp.eliminate_macro_nodes();
2084       igvn.set_delay_transform(false);
2085 
2086       igvn.optimize();
2087       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2088 
2089       if (failing())  return;
2090     }
2091   }
2092 
2093   // Loop transforms on the ideal graph.  Range Check Elimination,
2094   // peeling, unrolling, etc.
2095 
2096   // Set loop opts counter
2097   loop_opts_cnt = num_loop_opts();
2098   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2099     {
2100       TracePhase t2("idealLoop", &_t_idealLoop, true);
2101       PhaseIdealLoop ideal_loop( igvn, true );
2102       loop_opts_cnt--;
2103       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2104       if (failing())  return;
2105     }
2106     // Loop opts pass if partial peeling occurred in previous pass
2107     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2108       TracePhase t3("idealLoop", &_t_idealLoop, true);
2109       PhaseIdealLoop ideal_loop( igvn, false );
2110       loop_opts_cnt--;
2111       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2112       if (failing())  return;
2113     }
2114     // Loop opts pass for loop-unrolling before CCP
2115     if(major_progress() && (loop_opts_cnt > 0)) {
2116       TracePhase t4("idealLoop", &_t_idealLoop, true);
2117       PhaseIdealLoop ideal_loop( igvn, false );
2118       loop_opts_cnt--;
2119       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2120     }
2121     if (!failing()) {
2122       // Verify that last round of loop opts produced a valid graph
2123       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2124       PhaseIdealLoop::verify(igvn);
2125     }
2126   }
2127   if (failing())  return;
2128 
2129   // Conditional Constant Propagation;
2130   PhaseCCP ccp( &igvn );
2131   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2132   {
2133     TracePhase t2("ccp", &_t_ccp, true);
2134     ccp.do_transform();
2135   }
2136   print_method(PHASE_CPP1, 2);
2137 
2138   assert( true, "Break here to ccp.dump_old2new_map()");
2139 
2140   // Iterative Global Value Numbering, including ideal transforms
2141   {
2142     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2143     igvn = ccp;
2144     igvn.optimize();
2145   }
2146 
2147   print_method(PHASE_ITER_GVN2, 2);
2148 
2149   if (failing())  return;
2150 
2151   // Loop transforms on the ideal graph.  Range Check Elimination,
2152   // peeling, unrolling, etc.
2153   if(loop_opts_cnt > 0) {
2154     debug_only( int cnt = 0; );
2155     while(major_progress() && (loop_opts_cnt > 0)) {
2156       TracePhase t2("idealLoop", &_t_idealLoop, true);
2157       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2158       PhaseIdealLoop ideal_loop( igvn, true);
2159       loop_opts_cnt--;
2160       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2161       if (failing())  return;
2162     }
2163   }
2164 
2165   {
2166     // Verify that all previous optimizations produced a valid graph
2167     // at least to this point, even if no loop optimizations were done.
2168     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2169     PhaseIdealLoop::verify(igvn);
2170   }
2171 
2172   {
2173     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2174     PhaseMacroExpand  mex(igvn);
2175     if (mex.expand_macro_nodes()) {
2176       assert(failing(), "must bail out w/ explicit message");
2177       return;
2178     }
2179   }
2180 
2181  } // (End scope of igvn; run destructor if necessary for asserts.)
2182 
2183   dump_inlining();
2184   // A method with only infinite loops has no edges entering loops from root
2185   {
2186     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2187     if (final_graph_reshaping()) {
2188       assert(failing(), "must bail out w/ explicit message");
2189       return;
2190     }
2191   }
2192 
2193   print_method(PHASE_OPTIMIZE_FINISHED, 2);
2194 }
2195 
2196 
2197 //------------------------------Code_Gen---------------------------------------
2198 // Given a graph, generate code for it
2199 void Compile::Code_Gen() {
2200   if (failing()) {
2201     return;
2202   }
2203 
2204   // Perform instruction selection.  You might think we could reclaim Matcher
2205   // memory PDQ, but actually the Matcher is used in generating spill code.
2206   // Internals of the Matcher (including some VectorSets) must remain live
2207   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2208   // set a bit in reclaimed memory.
2209 
2210   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2211   // nodes.  Mapping is only valid at the root of each matched subtree.
2212   NOT_PRODUCT( verify_graph_edges(); )
2213 
2214   Matcher matcher;
2215   _matcher = &matcher;
2216   {
2217     TracePhase t2("matcher", &_t_matcher, true);
2218     matcher.match();
2219   }
2220   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2221   // nodes.  Mapping is only valid at the root of each matched subtree.
2222   NOT_PRODUCT( verify_graph_edges(); )
2223 
2224   // If you have too many nodes, or if matching has failed, bail out
2225   check_node_count(0, "out of nodes matching instructions");
2226   if (failing()) {
2227     return;
2228   }
2229 
2230   // Build a proper-looking CFG
2231   PhaseCFG cfg(node_arena(), root(), matcher);
2232   _cfg = &cfg;
2233   {
2234     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2235     bool success = cfg.do_global_code_motion();
2236     if (!success) {
2237       return;
2238     }
2239 
2240     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2241     NOT_PRODUCT( verify_graph_edges(); )
2242     debug_only( cfg.verify(); )
2243   }
2244 
2245   PhaseChaitin regalloc(unique(), cfg, matcher);
2246   _regalloc = &regalloc;
2247   {
2248     TracePhase t2("regalloc", &_t_registerAllocation, true);
2249     // Perform register allocation.  After Chaitin, use-def chains are
2250     // no longer accurate (at spill code) and so must be ignored.
2251     // Node->LRG->reg mappings are still accurate.
2252     _regalloc->Register_Allocate();
2253 
2254     // Bail out if the allocator builds too many nodes
2255     if (failing()) {
2256       return;
2257     }
2258   }
2259 
2260   // Prior to register allocation we kept empty basic blocks in case the
2261   // the allocator needed a place to spill.  After register allocation we
2262   // are not adding any new instructions.  If any basic block is empty, we
2263   // can now safely remove it.
2264   {
2265     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2266     cfg.remove_empty_blocks();
2267     if (do_freq_based_layout()) {
2268       PhaseBlockLayout layout(cfg);
2269     } else {
2270       cfg.set_loop_alignment();
2271     }
2272     cfg.fixup_flow();
2273   }
2274 
2275   // Apply peephole optimizations
2276   if( OptoPeephole ) {
2277     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2278     PhasePeephole peep( _regalloc, cfg);
2279     peep.do_transform();
2280   }
2281 
2282   // Convert Nodes to instruction bits in a buffer
2283   {
2284     // %%%% workspace merge brought two timers together for one job
2285     TracePhase t2a("output", &_t_output, true);
2286     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2287     Output();
2288   }
2289 
2290   print_method(PHASE_FINAL_CODE);
2291 
2292   // He's dead, Jim.
2293   _cfg     = (PhaseCFG*)0xdeadbeef;
2294   _regalloc = (PhaseChaitin*)0xdeadbeef;
2295 }
2296 
2297 
2298 //------------------------------dump_asm---------------------------------------
2299 // Dump formatted assembly
2300 #ifndef PRODUCT
2301 void Compile::dump_asm(int *pcs, uint pc_limit) {
2302   bool cut_short = false;
2303   tty->print_cr("#");
2304   tty->print("#  ");  _tf->dump();  tty->cr();
2305   tty->print_cr("#");
2306 
2307   // For all blocks
2308   int pc = 0x0;                 // Program counter
2309   char starts_bundle = ' ';
2310   _regalloc->dump_frame();
2311 
2312   Node *n = NULL;
2313   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2314     if (VMThread::should_terminate()) {
2315       cut_short = true;
2316       break;
2317     }
2318     Block* block = _cfg->get_block(i);
2319     if (block->is_connector() && !Verbose) {
2320       continue;
2321     }
2322     n = block->head();
2323     if (pcs && n->_idx < pc_limit) {
2324       tty->print("%3.3x   ", pcs[n->_idx]);
2325     } else {
2326       tty->print("      ");
2327     }
2328     block->dump_head(_cfg);
2329     if (block->is_connector()) {
2330       tty->print_cr("        # Empty connector block");
2331     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2332       tty->print_cr("        # Block is sole successor of call");
2333     }
2334 
2335     // For all instructions
2336     Node *delay = NULL;
2337     for (uint j = 0; j < block->number_of_nodes(); j++) {
2338       if (VMThread::should_terminate()) {
2339         cut_short = true;
2340         break;
2341       }
2342       n = block->get_node(j);
2343       if (valid_bundle_info(n)) {
2344         Bundle* bundle = node_bundling(n);
2345         if (bundle->used_in_unconditional_delay()) {
2346           delay = n;
2347           continue;
2348         }
2349         if (bundle->starts_bundle()) {
2350           starts_bundle = '+';
2351         }
2352       }
2353 
2354       if (WizardMode) {
2355         n->dump();
2356       }
2357 
2358       if( !n->is_Region() &&    // Dont print in the Assembly
2359           !n->is_Phi() &&       // a few noisely useless nodes
2360           !n->is_Proj() &&
2361           !n->is_MachTemp() &&
2362           !n->is_SafePointScalarObject() &&
2363           !n->is_Catch() &&     // Would be nice to print exception table targets
2364           !n->is_MergeMem() &&  // Not very interesting
2365           !n->is_top() &&       // Debug info table constants
2366           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2367           ) {
2368         if (pcs && n->_idx < pc_limit)
2369           tty->print("%3.3x", pcs[n->_idx]);
2370         else
2371           tty->print("   ");
2372         tty->print(" %c ", starts_bundle);
2373         starts_bundle = ' ';
2374         tty->print("\t");
2375         n->format(_regalloc, tty);
2376         tty->cr();
2377       }
2378 
2379       // If we have an instruction with a delay slot, and have seen a delay,
2380       // then back up and print it
2381       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2382         assert(delay != NULL, "no unconditional delay instruction");
2383         if (WizardMode) delay->dump();
2384 
2385         if (node_bundling(delay)->starts_bundle())
2386           starts_bundle = '+';
2387         if (pcs && n->_idx < pc_limit)
2388           tty->print("%3.3x", pcs[n->_idx]);
2389         else
2390           tty->print("   ");
2391         tty->print(" %c ", starts_bundle);
2392         starts_bundle = ' ';
2393         tty->print("\t");
2394         delay->format(_regalloc, tty);
2395         tty->print_cr("");
2396         delay = NULL;
2397       }
2398 
2399       // Dump the exception table as well
2400       if( n->is_Catch() && (Verbose || WizardMode) ) {
2401         // Print the exception table for this offset
2402         _handler_table.print_subtable_for(pc);
2403       }
2404     }
2405 
2406     if (pcs && n->_idx < pc_limit)
2407       tty->print_cr("%3.3x", pcs[n->_idx]);
2408     else
2409       tty->print_cr("");
2410 
2411     assert(cut_short || delay == NULL, "no unconditional delay branch");
2412 
2413   } // End of per-block dump
2414   tty->print_cr("");
2415 
2416   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2417 }
2418 #endif
2419 
2420 //------------------------------Final_Reshape_Counts---------------------------
2421 // This class defines counters to help identify when a method
2422 // may/must be executed using hardware with only 24-bit precision.
2423 struct Final_Reshape_Counts : public StackObj {
2424   int  _call_count;             // count non-inlined 'common' calls
2425   int  _float_count;            // count float ops requiring 24-bit precision
2426   int  _double_count;           // count double ops requiring more precision
2427   int  _java_call_count;        // count non-inlined 'java' calls
2428   int  _inner_loop_count;       // count loops which need alignment
2429   VectorSet _visited;           // Visitation flags
2430   Node_List _tests;             // Set of IfNodes & PCTableNodes
2431 
2432   Final_Reshape_Counts() :
2433     _call_count(0), _float_count(0), _double_count(0),
2434     _java_call_count(0), _inner_loop_count(0),
2435     _visited( Thread::current()->resource_area() ) { }
2436 
2437   void inc_call_count  () { _call_count  ++; }
2438   void inc_float_count () { _float_count ++; }
2439   void inc_double_count() { _double_count++; }
2440   void inc_java_call_count() { _java_call_count++; }
2441   void inc_inner_loop_count() { _inner_loop_count++; }
2442 
2443   int  get_call_count  () const { return _call_count  ; }
2444   int  get_float_count () const { return _float_count ; }
2445   int  get_double_count() const { return _double_count; }
2446   int  get_java_call_count() const { return _java_call_count; }
2447   int  get_inner_loop_count() const { return _inner_loop_count; }
2448 };
2449 
2450 #ifdef ASSERT
2451 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2452   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2453   // Make sure the offset goes inside the instance layout.
2454   return k->contains_field_offset(tp->offset());
2455   // Note that OffsetBot and OffsetTop are very negative.
2456 }
2457 #endif
2458 
2459 // Eliminate trivially redundant StoreCMs and accumulate their
2460 // precedence edges.
2461 void Compile::eliminate_redundant_card_marks(Node* n) {
2462   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2463   if (n->in(MemNode::Address)->outcnt() > 1) {
2464     // There are multiple users of the same address so it might be
2465     // possible to eliminate some of the StoreCMs
2466     Node* mem = n->in(MemNode::Memory);
2467     Node* adr = n->in(MemNode::Address);
2468     Node* val = n->in(MemNode::ValueIn);
2469     Node* prev = n;
2470     bool done = false;
2471     // Walk the chain of StoreCMs eliminating ones that match.  As
2472     // long as it's a chain of single users then the optimization is
2473     // safe.  Eliminating partially redundant StoreCMs would require
2474     // cloning copies down the other paths.
2475     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2476       if (adr == mem->in(MemNode::Address) &&
2477           val == mem->in(MemNode::ValueIn)) {
2478         // redundant StoreCM
2479         if (mem->req() > MemNode::OopStore) {
2480           // Hasn't been processed by this code yet.
2481           n->add_prec(mem->in(MemNode::OopStore));
2482         } else {
2483           // Already converted to precedence edge
2484           for (uint i = mem->req(); i < mem->len(); i++) {
2485             // Accumulate any precedence edges
2486             if (mem->in(i) != NULL) {
2487               n->add_prec(mem->in(i));
2488             }
2489           }
2490           // Everything above this point has been processed.
2491           done = true;
2492         }
2493         // Eliminate the previous StoreCM
2494         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2495         assert(mem->outcnt() == 0, "should be dead");
2496         mem->disconnect_inputs(NULL, this);
2497       } else {
2498         prev = mem;
2499       }
2500       mem = prev->in(MemNode::Memory);
2501     }
2502   }
2503 }
2504 
2505 //------------------------------final_graph_reshaping_impl----------------------
2506 // Implement items 1-5 from final_graph_reshaping below.
2507 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2508 
2509   if ( n->outcnt() == 0 ) return; // dead node
2510   uint nop = n->Opcode();
2511 
2512   // Check for 2-input instruction with "last use" on right input.
2513   // Swap to left input.  Implements item (2).
2514   if( n->req() == 3 &&          // two-input instruction
2515       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2516       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2517       n->in(2)->outcnt() == 1 &&// right use IS a last use
2518       !n->in(2)->is_Con() ) {   // right use is not a constant
2519     // Check for commutative opcode
2520     switch( nop ) {
2521     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2522     case Op_MaxI:  case Op_MinI:
2523     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2524     case Op_AndL:  case Op_XorL:  case Op_OrL:
2525     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2526       // Move "last use" input to left by swapping inputs
2527       n->swap_edges(1, 2);
2528       break;
2529     }
2530     default:
2531       break;
2532     }
2533   }
2534 
2535 #ifdef ASSERT
2536   if( n->is_Mem() ) {
2537     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2538     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2539             // oop will be recorded in oop map if load crosses safepoint
2540             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2541                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2542             "raw memory operations should have control edge");
2543   }
2544 #endif
2545   // Count FPU ops and common calls, implements item (3)
2546   switch( nop ) {
2547   // Count all float operations that may use FPU
2548   case Op_AddF:
2549   case Op_SubF:
2550   case Op_MulF:
2551   case Op_DivF:
2552   case Op_NegF:
2553   case Op_ModF:
2554   case Op_ConvI2F:
2555   case Op_ConF:
2556   case Op_CmpF:
2557   case Op_CmpF3:
2558   // case Op_ConvL2F: // longs are split into 32-bit halves
2559     frc.inc_float_count();
2560     break;
2561 
2562   case Op_ConvF2D:
2563   case Op_ConvD2F:
2564     frc.inc_float_count();
2565     frc.inc_double_count();
2566     break;
2567 
2568   // Count all double operations that may use FPU
2569   case Op_AddD:
2570   case Op_SubD:
2571   case Op_MulD:
2572   case Op_DivD:
2573   case Op_NegD:
2574   case Op_ModD:
2575   case Op_ConvI2D:
2576   case Op_ConvD2I:
2577   // case Op_ConvL2D: // handled by leaf call
2578   // case Op_ConvD2L: // handled by leaf call
2579   case Op_ConD:
2580   case Op_CmpD:
2581   case Op_CmpD3:
2582     frc.inc_double_count();
2583     break;
2584   case Op_Opaque1:              // Remove Opaque Nodes before matching
2585   case Op_Opaque2:              // Remove Opaque Nodes before matching
2586   case Op_Opaque3:
2587     n->subsume_by(n->in(1), this);
2588     break;
2589   case Op_CallStaticJava:
2590   case Op_CallJava:
2591   case Op_CallDynamicJava:
2592     frc.inc_java_call_count(); // Count java call site;
2593   case Op_CallRuntime:
2594   case Op_CallLeaf:
2595   case Op_CallLeafNoFP: {
2596     assert( n->is_Call(), "" );
2597     CallNode *call = n->as_Call();
2598     // Count call sites where the FP mode bit would have to be flipped.
2599     // Do not count uncommon runtime calls:
2600     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2601     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2602     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2603       frc.inc_call_count();   // Count the call site
2604     } else {                  // See if uncommon argument is shared
2605       Node *n = call->in(TypeFunc::Parms);
2606       int nop = n->Opcode();
2607       // Clone shared simple arguments to uncommon calls, item (1).
2608       if( n->outcnt() > 1 &&
2609           !n->is_Proj() &&
2610           nop != Op_CreateEx &&
2611           nop != Op_CheckCastPP &&
2612           nop != Op_DecodeN &&
2613           nop != Op_DecodeNKlass &&
2614           !n->is_Mem() ) {
2615         Node *x = n->clone();
2616         call->set_req( TypeFunc::Parms, x );
2617       }
2618     }
2619     break;
2620   }
2621 
2622   case Op_StoreD:
2623   case Op_LoadD:
2624   case Op_LoadD_unaligned:
2625     frc.inc_double_count();
2626     goto handle_mem;
2627   case Op_StoreF:
2628   case Op_LoadF:
2629     frc.inc_float_count();
2630     goto handle_mem;
2631 
2632   case Op_StoreCM:
2633     {
2634       // Convert OopStore dependence into precedence edge
2635       Node* prec = n->in(MemNode::OopStore);
2636       n->del_req(MemNode::OopStore);
2637       n->add_prec(prec);
2638       eliminate_redundant_card_marks(n);
2639     }
2640 
2641     // fall through
2642 
2643   case Op_StoreB:
2644   case Op_StoreC:
2645   case Op_StorePConditional:
2646   case Op_StoreI:
2647   case Op_StoreL:
2648   case Op_StoreIConditional:
2649   case Op_StoreLConditional:
2650   case Op_CompareAndSwapI:
2651   case Op_CompareAndSwapL:
2652   case Op_CompareAndSwapP:
2653   case Op_CompareAndSwapN:
2654   case Op_GetAndAddI:
2655   case Op_GetAndAddL:
2656   case Op_GetAndSetI:
2657   case Op_GetAndSetL:
2658   case Op_GetAndSetP:
2659   case Op_GetAndSetN:
2660   case Op_StoreP:
2661   case Op_StoreN:
2662   case Op_StoreNKlass:
2663   case Op_LoadB:
2664   case Op_LoadUB:
2665   case Op_LoadUS:
2666   case Op_LoadI:
2667   case Op_LoadKlass:
2668   case Op_LoadNKlass:
2669   case Op_LoadL:
2670   case Op_LoadL_unaligned:
2671   case Op_LoadPLocked:
2672   case Op_LoadP:
2673   case Op_LoadN:
2674   case Op_LoadRange:
2675   case Op_LoadS: {
2676   handle_mem:
2677 #ifdef ASSERT
2678     if( VerifyOptoOopOffsets ) {
2679       assert( n->is_Mem(), "" );
2680       MemNode *mem  = (MemNode*)n;
2681       // Check to see if address types have grounded out somehow.
2682       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2683       assert( !tp || oop_offset_is_sane(tp), "" );
2684     }
2685 #endif
2686     break;
2687   }
2688 
2689   case Op_AddP: {               // Assert sane base pointers
2690     Node *addp = n->in(AddPNode::Address);
2691     assert( !addp->is_AddP() ||
2692             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2693             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2694             "Base pointers must match" );
2695 #ifdef _LP64
2696     if ((UseCompressedOops || UseCompressedClassPointers) &&
2697         addp->Opcode() == Op_ConP &&
2698         addp == n->in(AddPNode::Base) &&
2699         n->in(AddPNode::Offset)->is_Con()) {
2700       // Use addressing with narrow klass to load with offset on x86.
2701       // On sparc loading 32-bits constant and decoding it have less
2702       // instructions (4) then load 64-bits constant (7).
2703       // Do this transformation here since IGVN will convert ConN back to ConP.
2704       const Type* t = addp->bottom_type();
2705       if (t->isa_oopptr() || t->isa_klassptr()) {
2706         Node* nn = NULL;
2707 
2708         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2709 
2710         // Look for existing ConN node of the same exact type.
2711         Node* r  = root();
2712         uint cnt = r->outcnt();
2713         for (uint i = 0; i < cnt; i++) {
2714           Node* m = r->raw_out(i);
2715           if (m!= NULL && m->Opcode() == op &&
2716               m->bottom_type()->make_ptr() == t) {
2717             nn = m;
2718             break;
2719           }
2720         }
2721         if (nn != NULL) {
2722           // Decode a narrow oop to match address
2723           // [R12 + narrow_oop_reg<<3 + offset]
2724           if (t->isa_oopptr()) {
2725             nn = new (this) DecodeNNode(nn, t);
2726           } else {
2727             nn = new (this) DecodeNKlassNode(nn, t);
2728           }
2729           n->set_req(AddPNode::Base, nn);
2730           n->set_req(AddPNode::Address, nn);
2731           if (addp->outcnt() == 0) {
2732             addp->disconnect_inputs(NULL, this);
2733           }
2734         }
2735       }
2736     }
2737 #endif
2738     break;
2739   }
2740 
2741 #ifdef _LP64
2742   case Op_CastPP:
2743     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2744       Node* in1 = n->in(1);
2745       const Type* t = n->bottom_type();
2746       Node* new_in1 = in1->clone();
2747       new_in1->as_DecodeN()->set_type(t);
2748 
2749       if (!Matcher::narrow_oop_use_complex_address()) {
2750         //
2751         // x86, ARM and friends can handle 2 adds in addressing mode
2752         // and Matcher can fold a DecodeN node into address by using
2753         // a narrow oop directly and do implicit NULL check in address:
2754         //
2755         // [R12 + narrow_oop_reg<<3 + offset]
2756         // NullCheck narrow_oop_reg
2757         //
2758         // On other platforms (Sparc) we have to keep new DecodeN node and
2759         // use it to do implicit NULL check in address:
2760         //
2761         // decode_not_null narrow_oop_reg, base_reg
2762         // [base_reg + offset]
2763         // NullCheck base_reg
2764         //
2765         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2766         // to keep the information to which NULL check the new DecodeN node
2767         // corresponds to use it as value in implicit_null_check().
2768         //
2769         new_in1->set_req(0, n->in(0));
2770       }
2771 
2772       n->subsume_by(new_in1, this);
2773       if (in1->outcnt() == 0) {
2774         in1->disconnect_inputs(NULL, this);
2775       }
2776     }
2777     break;
2778 
2779   case Op_CmpP:
2780     // Do this transformation here to preserve CmpPNode::sub() and
2781     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2782     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2783       Node* in1 = n->in(1);
2784       Node* in2 = n->in(2);
2785       if (!in1->is_DecodeNarrowPtr()) {
2786         in2 = in1;
2787         in1 = n->in(2);
2788       }
2789       assert(in1->is_DecodeNarrowPtr(), "sanity");
2790 
2791       Node* new_in2 = NULL;
2792       if (in2->is_DecodeNarrowPtr()) {
2793         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2794         new_in2 = in2->in(1);
2795       } else if (in2->Opcode() == Op_ConP) {
2796         const Type* t = in2->bottom_type();
2797         if (t == TypePtr::NULL_PTR) {
2798           assert(in1->is_DecodeN(), "compare klass to null?");
2799           // Don't convert CmpP null check into CmpN if compressed
2800           // oops implicit null check is not generated.
2801           // This will allow to generate normal oop implicit null check.
2802           if (Matcher::gen_narrow_oop_implicit_null_checks())
2803             new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2804           //
2805           // This transformation together with CastPP transformation above
2806           // will generated code for implicit NULL checks for compressed oops.
2807           //
2808           // The original code after Optimize()
2809           //
2810           //    LoadN memory, narrow_oop_reg
2811           //    decode narrow_oop_reg, base_reg
2812           //    CmpP base_reg, NULL
2813           //    CastPP base_reg // NotNull
2814           //    Load [base_reg + offset], val_reg
2815           //
2816           // after these transformations will be
2817           //
2818           //    LoadN memory, narrow_oop_reg
2819           //    CmpN narrow_oop_reg, NULL
2820           //    decode_not_null narrow_oop_reg, base_reg
2821           //    Load [base_reg + offset], val_reg
2822           //
2823           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2824           // since narrow oops can be used in debug info now (see the code in
2825           // final_graph_reshaping_walk()).
2826           //
2827           // At the end the code will be matched to
2828           // on x86:
2829           //
2830           //    Load_narrow_oop memory, narrow_oop_reg
2831           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2832           //    NullCheck narrow_oop_reg
2833           //
2834           // and on sparc:
2835           //
2836           //    Load_narrow_oop memory, narrow_oop_reg
2837           //    decode_not_null narrow_oop_reg, base_reg
2838           //    Load [base_reg + offset], val_reg
2839           //    NullCheck base_reg
2840           //
2841         } else if (t->isa_oopptr()) {
2842           new_in2 = ConNode::make(this, t->make_narrowoop());
2843         } else if (t->isa_klassptr()) {
2844           new_in2 = ConNode::make(this, t->make_narrowklass());
2845         }
2846       }
2847       if (new_in2 != NULL) {
2848         Node* cmpN = new (this) CmpNNode(in1->in(1), new_in2);
2849         n->subsume_by(cmpN, this);
2850         if (in1->outcnt() == 0) {
2851           in1->disconnect_inputs(NULL, this);
2852         }
2853         if (in2->outcnt() == 0) {
2854           in2->disconnect_inputs(NULL, this);
2855         }
2856       }
2857     }
2858     break;
2859 
2860   case Op_DecodeN:
2861   case Op_DecodeNKlass:
2862     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2863     // DecodeN could be pinned when it can't be fold into
2864     // an address expression, see the code for Op_CastPP above.
2865     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2866     break;
2867 
2868   case Op_EncodeP:
2869   case Op_EncodePKlass: {
2870     Node* in1 = n->in(1);
2871     if (in1->is_DecodeNarrowPtr()) {
2872       n->subsume_by(in1->in(1), this);
2873     } else if (in1->Opcode() == Op_ConP) {
2874       const Type* t = in1->bottom_type();
2875       if (t == TypePtr::NULL_PTR) {
2876         assert(t->isa_oopptr(), "null klass?");
2877         n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2878       } else if (t->isa_oopptr()) {
2879         n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2880       } else if (t->isa_klassptr()) {
2881         n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2882       }
2883     }
2884     if (in1->outcnt() == 0) {
2885       in1->disconnect_inputs(NULL, this);
2886     }
2887     break;
2888   }
2889 
2890   case Op_Proj: {
2891     if (OptimizeStringConcat) {
2892       ProjNode* p = n->as_Proj();
2893       if (p->_is_io_use) {
2894         // Separate projections were used for the exception path which
2895         // are normally removed by a late inline.  If it wasn't inlined
2896         // then they will hang around and should just be replaced with
2897         // the original one.
2898         Node* proj = NULL;
2899         // Replace with just one
2900         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2901           Node *use = i.get();
2902           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2903             proj = use;
2904             break;
2905           }
2906         }
2907         assert(proj != NULL, "must be found");
2908         p->subsume_by(proj, this);
2909       }
2910     }
2911     break;
2912   }
2913 
2914   case Op_Phi:
2915     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2916       // The EncodeP optimization may create Phi with the same edges
2917       // for all paths. It is not handled well by Register Allocator.
2918       Node* unique_in = n->in(1);
2919       assert(unique_in != NULL, "");
2920       uint cnt = n->req();
2921       for (uint i = 2; i < cnt; i++) {
2922         Node* m = n->in(i);
2923         assert(m != NULL, "");
2924         if (unique_in != m)
2925           unique_in = NULL;
2926       }
2927       if (unique_in != NULL) {
2928         n->subsume_by(unique_in, this);
2929       }
2930     }
2931     break;
2932 
2933 #endif
2934 
2935   case Op_ModI:
2936     if (UseDivMod) {
2937       // Check if a%b and a/b both exist
2938       Node* d = n->find_similar(Op_DivI);
2939       if (d) {
2940         // Replace them with a fused divmod if supported
2941         if (Matcher::has_match_rule(Op_DivModI)) {
2942           DivModINode* divmod = DivModINode::make(this, n);
2943           d->subsume_by(divmod->div_proj(), this);
2944           n->subsume_by(divmod->mod_proj(), this);
2945         } else {
2946           // replace a%b with a-((a/b)*b)
2947           Node* mult = new (this) MulINode(d, d->in(2));
2948           Node* sub  = new (this) SubINode(d->in(1), mult);
2949           n->subsume_by(sub, this);
2950         }
2951       }
2952     }
2953     break;
2954 
2955   case Op_ModL:
2956     if (UseDivMod) {
2957       // Check if a%b and a/b both exist
2958       Node* d = n->find_similar(Op_DivL);
2959       if (d) {
2960         // Replace them with a fused divmod if supported
2961         if (Matcher::has_match_rule(Op_DivModL)) {
2962           DivModLNode* divmod = DivModLNode::make(this, n);
2963           d->subsume_by(divmod->div_proj(), this);
2964           n->subsume_by(divmod->mod_proj(), this);
2965         } else {
2966           // replace a%b with a-((a/b)*b)
2967           Node* mult = new (this) MulLNode(d, d->in(2));
2968           Node* sub  = new (this) SubLNode(d->in(1), mult);
2969           n->subsume_by(sub, this);
2970         }
2971       }
2972     }
2973     break;
2974 
2975   case Op_LoadVector:
2976   case Op_StoreVector:
2977     break;
2978 
2979   case Op_PackB:
2980   case Op_PackS:
2981   case Op_PackI:
2982   case Op_PackF:
2983   case Op_PackL:
2984   case Op_PackD:
2985     if (n->req()-1 > 2) {
2986       // Replace many operand PackNodes with a binary tree for matching
2987       PackNode* p = (PackNode*) n;
2988       Node* btp = p->binary_tree_pack(this, 1, n->req());
2989       n->subsume_by(btp, this);
2990     }
2991     break;
2992   case Op_Loop:
2993   case Op_CountedLoop:
2994     if (n->as_Loop()->is_inner_loop()) {
2995       frc.inc_inner_loop_count();
2996     }
2997     break;
2998   case Op_LShiftI:
2999   case Op_RShiftI:
3000   case Op_URShiftI:
3001   case Op_LShiftL:
3002   case Op_RShiftL:
3003   case Op_URShiftL:
3004     if (Matcher::need_masked_shift_count) {
3005       // The cpu's shift instructions don't restrict the count to the
3006       // lower 5/6 bits. We need to do the masking ourselves.
3007       Node* in2 = n->in(2);
3008       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3009       const TypeInt* t = in2->find_int_type();
3010       if (t != NULL && t->is_con()) {
3011         juint shift = t->get_con();
3012         if (shift > mask) { // Unsigned cmp
3013           n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
3014         }
3015       } else {
3016         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3017           Node* shift = new (this) AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
3018           n->set_req(2, shift);
3019         }
3020       }
3021       if (in2->outcnt() == 0) { // Remove dead node
3022         in2->disconnect_inputs(NULL, this);
3023       }
3024     }
3025     break;
3026   case Op_MemBarStoreStore:
3027   case Op_MemBarRelease:
3028     // Break the link with AllocateNode: it is no longer useful and
3029     // confuses register allocation.
3030     if (n->req() > MemBarNode::Precedent) {
3031       n->set_req(MemBarNode::Precedent, top());
3032     }
3033     break;
3034   default:
3035     assert( !n->is_Call(), "" );
3036     assert( !n->is_Mem(), "" );
3037     break;
3038   }
3039 
3040   // Collect CFG split points
3041   if (n->is_MultiBranch())
3042     frc._tests.push(n);
3043 }
3044 
3045 //------------------------------final_graph_reshaping_walk---------------------
3046 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3047 // requires that the walk visits a node's inputs before visiting the node.
3048 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3049   ResourceArea *area = Thread::current()->resource_area();
3050   Unique_Node_List sfpt(area);
3051 
3052   frc._visited.set(root->_idx); // first, mark node as visited
3053   uint cnt = root->req();
3054   Node *n = root;
3055   uint  i = 0;
3056   while (true) {
3057     if (i < cnt) {
3058       // Place all non-visited non-null inputs onto stack
3059       Node* m = n->in(i);
3060       ++i;
3061       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3062         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL)
3063           sfpt.push(m);
3064         cnt = m->req();
3065         nstack.push(n, i); // put on stack parent and next input's index
3066         n = m;
3067         i = 0;
3068       }
3069     } else {
3070       // Now do post-visit work
3071       final_graph_reshaping_impl( n, frc );
3072       if (nstack.is_empty())
3073         break;             // finished
3074       n = nstack.node();   // Get node from stack
3075       cnt = n->req();
3076       i = nstack.index();
3077       nstack.pop();        // Shift to the next node on stack
3078     }
3079   }
3080 
3081   // Skip next transformation if compressed oops are not used.
3082   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3083       (!UseCompressedOops && !UseCompressedClassPointers))
3084     return;
3085 
3086   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3087   // It could be done for an uncommon traps or any safepoints/calls
3088   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3089   while (sfpt.size() > 0) {
3090     n = sfpt.pop();
3091     JVMState *jvms = n->as_SafePoint()->jvms();
3092     assert(jvms != NULL, "sanity");
3093     int start = jvms->debug_start();
3094     int end   = n->req();
3095     bool is_uncommon = (n->is_CallStaticJava() &&
3096                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3097     for (int j = start; j < end; j++) {
3098       Node* in = n->in(j);
3099       if (in->is_DecodeNarrowPtr()) {
3100         bool safe_to_skip = true;
3101         if (!is_uncommon ) {
3102           // Is it safe to skip?
3103           for (uint i = 0; i < in->outcnt(); i++) {
3104             Node* u = in->raw_out(i);
3105             if (!u->is_SafePoint() ||
3106                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3107               safe_to_skip = false;
3108             }
3109           }
3110         }
3111         if (safe_to_skip) {
3112           n->set_req(j, in->in(1));
3113         }
3114         if (in->outcnt() == 0) {
3115           in->disconnect_inputs(NULL, this);
3116         }
3117       }
3118     }
3119   }
3120 }
3121 
3122 //------------------------------final_graph_reshaping--------------------------
3123 // Final Graph Reshaping.
3124 //
3125 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3126 //     and not commoned up and forced early.  Must come after regular
3127 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3128 //     inputs to Loop Phis; these will be split by the allocator anyways.
3129 //     Remove Opaque nodes.
3130 // (2) Move last-uses by commutative operations to the left input to encourage
3131 //     Intel update-in-place two-address operations and better register usage
3132 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3133 //     calls canonicalizing them back.
3134 // (3) Count the number of double-precision FP ops, single-precision FP ops
3135 //     and call sites.  On Intel, we can get correct rounding either by
3136 //     forcing singles to memory (requires extra stores and loads after each
3137 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3138 //     clearing the mode bit around call sites).  The mode bit is only used
3139 //     if the relative frequency of single FP ops to calls is low enough.
3140 //     This is a key transform for SPEC mpeg_audio.
3141 // (4) Detect infinite loops; blobs of code reachable from above but not
3142 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3143 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3144 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3145 //     Detection is by looking for IfNodes where only 1 projection is
3146 //     reachable from below or CatchNodes missing some targets.
3147 // (5) Assert for insane oop offsets in debug mode.
3148 
3149 bool Compile::final_graph_reshaping() {
3150   // an infinite loop may have been eliminated by the optimizer,
3151   // in which case the graph will be empty.
3152   if (root()->req() == 1) {
3153     record_method_not_compilable("trivial infinite loop");
3154     return true;
3155   }
3156 
3157   // Expensive nodes have their control input set to prevent the GVN
3158   // from freely commoning them. There's no GVN beyond this point so
3159   // no need to keep the control input. We want the expensive nodes to
3160   // be freely moved to the least frequent code path by gcm.
3161   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3162   for (int i = 0; i < expensive_count(); i++) {
3163     _expensive_nodes->at(i)->set_req(0, NULL);
3164   }
3165 
3166   Final_Reshape_Counts frc;
3167 
3168   // Visit everybody reachable!
3169   // Allocate stack of size C->unique()/2 to avoid frequent realloc
3170   Node_Stack nstack(unique() >> 1);
3171   final_graph_reshaping_walk(nstack, root(), frc);
3172 
3173   // Check for unreachable (from below) code (i.e., infinite loops).
3174   for( uint i = 0; i < frc._tests.size(); i++ ) {
3175     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3176     // Get number of CFG targets.
3177     // Note that PCTables include exception targets after calls.
3178     uint required_outcnt = n->required_outcnt();
3179     if (n->outcnt() != required_outcnt) {
3180       // Check for a few special cases.  Rethrow Nodes never take the
3181       // 'fall-thru' path, so expected kids is 1 less.
3182       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3183         if (n->in(0)->in(0)->is_Call()) {
3184           CallNode *call = n->in(0)->in(0)->as_Call();
3185           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3186             required_outcnt--;      // Rethrow always has 1 less kid
3187           } else if (call->req() > TypeFunc::Parms &&
3188                      call->is_CallDynamicJava()) {
3189             // Check for null receiver. In such case, the optimizer has
3190             // detected that the virtual call will always result in a null
3191             // pointer exception. The fall-through projection of this CatchNode
3192             // will not be populated.
3193             Node *arg0 = call->in(TypeFunc::Parms);
3194             if (arg0->is_Type() &&
3195                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3196               required_outcnt--;
3197             }
3198           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3199                      call->req() > TypeFunc::Parms+1 &&
3200                      call->is_CallStaticJava()) {
3201             // Check for negative array length. In such case, the optimizer has
3202             // detected that the allocation attempt will always result in an
3203             // exception. There is no fall-through projection of this CatchNode .
3204             Node *arg1 = call->in(TypeFunc::Parms+1);
3205             if (arg1->is_Type() &&
3206                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3207               required_outcnt--;
3208             }
3209           }
3210         }
3211       }
3212       // Recheck with a better notion of 'required_outcnt'
3213       if (n->outcnt() != required_outcnt) {
3214         record_method_not_compilable("malformed control flow");
3215         return true;            // Not all targets reachable!
3216       }
3217     }
3218     // Check that I actually visited all kids.  Unreached kids
3219     // must be infinite loops.
3220     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3221       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3222         record_method_not_compilable("infinite loop");
3223         return true;            // Found unvisited kid; must be unreach
3224       }
3225   }
3226 
3227   // If original bytecodes contained a mixture of floats and doubles
3228   // check if the optimizer has made it homogenous, item (3).
3229   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3230       frc.get_float_count() > 32 &&
3231       frc.get_double_count() == 0 &&
3232       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3233     set_24_bit_selection_and_mode( false,  true );
3234   }
3235 
3236   set_java_calls(frc.get_java_call_count());
3237   set_inner_loops(frc.get_inner_loop_count());
3238 
3239   // No infinite loops, no reason to bail out.
3240   return false;
3241 }
3242 
3243 //-----------------------------too_many_traps----------------------------------
3244 // Report if there are too many traps at the current method and bci.
3245 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3246 bool Compile::too_many_traps(ciMethod* method,
3247                              int bci,
3248                              Deoptimization::DeoptReason reason) {
3249   ciMethodData* md = method->method_data();
3250   if (md->is_empty()) {
3251     // Assume the trap has not occurred, or that it occurred only
3252     // because of a transient condition during start-up in the interpreter.
3253     return false;
3254   }
3255   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3256   if (md->has_trap_at(bci, m, reason) != 0) {
3257     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3258     // Also, if there are multiple reasons, or if there is no per-BCI record,
3259     // assume the worst.
3260     if (log())
3261       log()->elem("observe trap='%s' count='%d'",
3262                   Deoptimization::trap_reason_name(reason),
3263                   md->trap_count(reason));
3264     return true;
3265   } else {
3266     // Ignore method/bci and see if there have been too many globally.
3267     return too_many_traps(reason, md);
3268   }
3269 }
3270 
3271 // Less-accurate variant which does not require a method and bci.
3272 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3273                              ciMethodData* logmd) {
3274   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3275     // Too many traps globally.
3276     // Note that we use cumulative trap_count, not just md->trap_count.
3277     if (log()) {
3278       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3279       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3280                   Deoptimization::trap_reason_name(reason),
3281                   mcount, trap_count(reason));
3282     }
3283     return true;
3284   } else {
3285     // The coast is clear.
3286     return false;
3287   }
3288 }
3289 
3290 //--------------------------too_many_recompiles--------------------------------
3291 // Report if there are too many recompiles at the current method and bci.
3292 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3293 // Is not eager to return true, since this will cause the compiler to use
3294 // Action_none for a trap point, to avoid too many recompilations.
3295 bool Compile::too_many_recompiles(ciMethod* method,
3296                                   int bci,
3297                                   Deoptimization::DeoptReason reason) {
3298   ciMethodData* md = method->method_data();
3299   if (md->is_empty()) {
3300     // Assume the trap has not occurred, or that it occurred only
3301     // because of a transient condition during start-up in the interpreter.
3302     return false;
3303   }
3304   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3305   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3306   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3307   Deoptimization::DeoptReason per_bc_reason
3308     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3309   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3310   if ((per_bc_reason == Deoptimization::Reason_none
3311        || md->has_trap_at(bci, m, reason) != 0)
3312       // The trap frequency measure we care about is the recompile count:
3313       && md->trap_recompiled_at(bci, m)
3314       && md->overflow_recompile_count() >= bc_cutoff) {
3315     // Do not emit a trap here if it has already caused recompilations.
3316     // Also, if there are multiple reasons, or if there is no per-BCI record,
3317     // assume the worst.
3318     if (log())
3319       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3320                   Deoptimization::trap_reason_name(reason),
3321                   md->trap_count(reason),
3322                   md->overflow_recompile_count());
3323     return true;
3324   } else if (trap_count(reason) != 0
3325              && decompile_count() >= m_cutoff) {
3326     // Too many recompiles globally, and we have seen this sort of trap.
3327     // Use cumulative decompile_count, not just md->decompile_count.
3328     if (log())
3329       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3330                   Deoptimization::trap_reason_name(reason),
3331                   md->trap_count(reason), trap_count(reason),
3332                   md->decompile_count(), decompile_count());
3333     return true;
3334   } else {
3335     // The coast is clear.
3336     return false;
3337   }
3338 }
3339 
3340 
3341 #ifndef PRODUCT
3342 //------------------------------verify_graph_edges---------------------------
3343 // Walk the Graph and verify that there is a one-to-one correspondence
3344 // between Use-Def edges and Def-Use edges in the graph.
3345 void Compile::verify_graph_edges(bool no_dead_code) {
3346   if (VerifyGraphEdges) {
3347     ResourceArea *area = Thread::current()->resource_area();
3348     Unique_Node_List visited(area);
3349     // Call recursive graph walk to check edges
3350     _root->verify_edges(visited);
3351     if (no_dead_code) {
3352       // Now make sure that no visited node is used by an unvisited node.
3353       bool dead_nodes = 0;
3354       Unique_Node_List checked(area);
3355       while (visited.size() > 0) {
3356         Node* n = visited.pop();
3357         checked.push(n);
3358         for (uint i = 0; i < n->outcnt(); i++) {
3359           Node* use = n->raw_out(i);
3360           if (checked.member(use))  continue;  // already checked
3361           if (visited.member(use))  continue;  // already in the graph
3362           if (use->is_Con())        continue;  // a dead ConNode is OK
3363           // At this point, we have found a dead node which is DU-reachable.
3364           if (dead_nodes++ == 0)
3365             tty->print_cr("*** Dead nodes reachable via DU edges:");
3366           use->dump(2);
3367           tty->print_cr("---");
3368           checked.push(use);  // No repeats; pretend it is now checked.
3369         }
3370       }
3371       assert(dead_nodes == 0, "using nodes must be reachable from root");
3372     }
3373   }
3374 }
3375 
3376 // Verify GC barriers consistency
3377 // Currently supported:
3378 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3379 void Compile::verify_barriers() {
3380   if (UseG1GC) {
3381     // Verify G1 pre-barriers
3382     const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3383 
3384     ResourceArea *area = Thread::current()->resource_area();
3385     Unique_Node_List visited(area);
3386     Node_List worklist(area);
3387     // We're going to walk control flow backwards starting from the Root
3388     worklist.push(_root);
3389     while (worklist.size() > 0) {
3390       Node* x = worklist.pop();
3391       if (x == NULL || x == top()) continue;
3392       if (visited.member(x)) {
3393         continue;
3394       } else {
3395         visited.push(x);
3396       }
3397 
3398       if (x->is_Region()) {
3399         for (uint i = 1; i < x->req(); i++) {
3400           worklist.push(x->in(i));
3401         }
3402       } else {
3403         worklist.push(x->in(0));
3404         // We are looking for the pattern:
3405         //                            /->ThreadLocal
3406         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3407         //              \->ConI(0)
3408         // We want to verify that the If and the LoadB have the same control
3409         // See GraphKit::g1_write_barrier_pre()
3410         if (x->is_If()) {
3411           IfNode *iff = x->as_If();
3412           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3413             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3414             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3415                 && cmp->in(1)->is_Load()) {
3416               LoadNode* load = cmp->in(1)->as_Load();
3417               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3418                   && load->in(2)->in(3)->is_Con()
3419                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3420 
3421                 Node* if_ctrl = iff->in(0);
3422                 Node* load_ctrl = load->in(0);
3423 
3424                 if (if_ctrl != load_ctrl) {
3425                   // Skip possible CProj->NeverBranch in infinite loops
3426                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3427                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3428                     if_ctrl = if_ctrl->in(0)->in(0);
3429                   }
3430                 }
3431                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3432               }
3433             }
3434           }
3435         }
3436       }
3437     }
3438   }
3439 }
3440 
3441 #endif
3442 
3443 // The Compile object keeps track of failure reasons separately from the ciEnv.
3444 // This is required because there is not quite a 1-1 relation between the
3445 // ciEnv and its compilation task and the Compile object.  Note that one
3446 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3447 // to backtrack and retry without subsuming loads.  Other than this backtracking
3448 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3449 // by the logic in C2Compiler.
3450 void Compile::record_failure(const char* reason) {
3451   if (log() != NULL) {
3452     log()->elem("failure reason='%s' phase='compile'", reason);
3453   }
3454   if (_failure_reason == NULL) {
3455     // Record the first failure reason.
3456     _failure_reason = reason;
3457   }
3458 
3459   EventCompilerFailure event;
3460   if (event.should_commit()) {
3461     event.set_compileID(Compile::compile_id());
3462     event.set_failure(reason);
3463     event.commit();
3464   }
3465 
3466   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3467     C->print_method(PHASE_FAILURE);
3468   }
3469   _root = NULL;  // flush the graph, too
3470 }
3471 
3472 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3473   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3474     _phase_name(name), _dolog(dolog)
3475 {
3476   if (dolog) {
3477     C = Compile::current();
3478     _log = C->log();
3479   } else {
3480     C = NULL;
3481     _log = NULL;
3482   }
3483   if (_log != NULL) {
3484     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3485     _log->stamp();
3486     _log->end_head();
3487   }
3488 }
3489 
3490 Compile::TracePhase::~TracePhase() {
3491 
3492   C = Compile::current();
3493   if (_dolog) {
3494     _log = C->log();
3495   } else {
3496     _log = NULL;
3497   }
3498 
3499 #ifdef ASSERT
3500   if (PrintIdealNodeCount) {
3501     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3502                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3503   }
3504 
3505   if (VerifyIdealNodeCount) {
3506     Compile::current()->print_missing_nodes();
3507   }
3508 #endif
3509 
3510   if (_log != NULL) {
3511     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3512   }
3513 }
3514 
3515 //=============================================================================
3516 // Two Constant's are equal when the type and the value are equal.
3517 bool Compile::Constant::operator==(const Constant& other) {
3518   if (type()          != other.type()         )  return false;
3519   if (can_be_reused() != other.can_be_reused())  return false;
3520   // For floating point values we compare the bit pattern.
3521   switch (type()) {
3522   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3523   case T_LONG:
3524   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3525   case T_OBJECT:
3526   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3527   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3528   case T_METADATA: return (_v._metadata == other._v._metadata);
3529   default: ShouldNotReachHere();
3530   }
3531   return false;
3532 }
3533 
3534 static int type_to_size_in_bytes(BasicType t) {
3535   switch (t) {
3536   case T_LONG:    return sizeof(jlong  );
3537   case T_FLOAT:   return sizeof(jfloat );
3538   case T_DOUBLE:  return sizeof(jdouble);
3539   case T_METADATA: return sizeof(Metadata*);
3540     // We use T_VOID as marker for jump-table entries (labels) which
3541     // need an internal word relocation.
3542   case T_VOID:
3543   case T_ADDRESS:
3544   case T_OBJECT:  return sizeof(jobject);
3545   }
3546 
3547   ShouldNotReachHere();
3548   return -1;
3549 }
3550 
3551 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3552   // sort descending
3553   if (a->freq() > b->freq())  return -1;
3554   if (a->freq() < b->freq())  return  1;
3555   return 0;
3556 }
3557 
3558 void Compile::ConstantTable::calculate_offsets_and_size() {
3559   // First, sort the array by frequencies.
3560   _constants.sort(qsort_comparator);
3561 
3562 #ifdef ASSERT
3563   // Make sure all jump-table entries were sorted to the end of the
3564   // array (they have a negative frequency).
3565   bool found_void = false;
3566   for (int i = 0; i < _constants.length(); i++) {
3567     Constant con = _constants.at(i);
3568     if (con.type() == T_VOID)
3569       found_void = true;  // jump-tables
3570     else
3571       assert(!found_void, "wrong sorting");
3572   }
3573 #endif
3574 
3575   int offset = 0;
3576   for (int i = 0; i < _constants.length(); i++) {
3577     Constant* con = _constants.adr_at(i);
3578 
3579     // Align offset for type.
3580     int typesize = type_to_size_in_bytes(con->type());
3581     offset = align_size_up(offset, typesize);
3582     con->set_offset(offset);   // set constant's offset
3583 
3584     if (con->type() == T_VOID) {
3585       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3586       offset = offset + typesize * n->outcnt();  // expand jump-table
3587     } else {
3588       offset = offset + typesize;
3589     }
3590   }
3591 
3592   // Align size up to the next section start (which is insts; see
3593   // CodeBuffer::align_at_start).
3594   assert(_size == -1, "already set?");
3595   _size = align_size_up(offset, CodeEntryAlignment);
3596 }
3597 
3598 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3599   MacroAssembler _masm(&cb);
3600   for (int i = 0; i < _constants.length(); i++) {
3601     Constant con = _constants.at(i);
3602     address constant_addr;
3603     switch (con.type()) {
3604     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3605     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3606     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3607     case T_OBJECT: {
3608       jobject obj = con.get_jobject();
3609       int oop_index = _masm.oop_recorder()->find_index(obj);
3610       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3611       break;
3612     }
3613     case T_ADDRESS: {
3614       address addr = (address) con.get_jobject();
3615       constant_addr = _masm.address_constant(addr);
3616       break;
3617     }
3618     // We use T_VOID as marker for jump-table entries (labels) which
3619     // need an internal word relocation.
3620     case T_VOID: {
3621       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3622       // Fill the jump-table with a dummy word.  The real value is
3623       // filled in later in fill_jump_table.
3624       address dummy = (address) n;
3625       constant_addr = _masm.address_constant(dummy);
3626       // Expand jump-table
3627       for (uint i = 1; i < n->outcnt(); i++) {
3628         address temp_addr = _masm.address_constant(dummy + i);
3629         assert(temp_addr, "consts section too small");
3630       }
3631       break;
3632     }
3633     case T_METADATA: {
3634       Metadata* obj = con.get_metadata();
3635       int metadata_index = _masm.oop_recorder()->find_index(obj);
3636       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3637       break;
3638     }
3639     default: ShouldNotReachHere();
3640     }
3641     assert(constant_addr, "consts section too small");
3642     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(), err_msg_res("must be: %d == %d", constant_addr - _masm.code()->consts()->start(), con.offset()));
3643   }
3644 }
3645 
3646 int Compile::ConstantTable::find_offset(Constant& con) const {
3647   int idx = _constants.find(con);
3648   assert(idx != -1, "constant must be in constant table");
3649   int offset = _constants.at(idx).offset();
3650   assert(offset != -1, "constant table not emitted yet?");
3651   return offset;
3652 }
3653 
3654 void Compile::ConstantTable::add(Constant& con) {
3655   if (con.can_be_reused()) {
3656     int idx = _constants.find(con);
3657     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3658       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3659       return;
3660     }
3661   }
3662   (void) _constants.append(con);
3663 }
3664 
3665 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3666   Block* b = Compile::current()->cfg()->get_block_for_node(n);
3667   Constant con(type, value, b->_freq);
3668   add(con);
3669   return con;
3670 }
3671 
3672 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3673   Constant con(metadata);
3674   add(con);
3675   return con;
3676 }
3677 
3678 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3679   jvalue value;
3680   BasicType type = oper->type()->basic_type();
3681   switch (type) {
3682   case T_LONG:    value.j = oper->constantL(); break;
3683   case T_FLOAT:   value.f = oper->constantF(); break;
3684   case T_DOUBLE:  value.d = oper->constantD(); break;
3685   case T_OBJECT:
3686   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3687   case T_METADATA: return add((Metadata*)oper->constant()); break;
3688   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3689   }
3690   return add(n, type, value);
3691 }
3692 
3693 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3694   jvalue value;
3695   // We can use the node pointer here to identify the right jump-table
3696   // as this method is called from Compile::Fill_buffer right before
3697   // the MachNodes are emitted and the jump-table is filled (means the
3698   // MachNode pointers do not change anymore).
3699   value.l = (jobject) n;
3700   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3701   add(con);
3702   return con;
3703 }
3704 
3705 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3706   // If called from Compile::scratch_emit_size do nothing.
3707   if (Compile::current()->in_scratch_emit_size())  return;
3708 
3709   assert(labels.is_nonempty(), "must be");
3710   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3711 
3712   // Since MachConstantNode::constant_offset() also contains
3713   // table_base_offset() we need to subtract the table_base_offset()
3714   // to get the plain offset into the constant table.
3715   int offset = n->constant_offset() - table_base_offset();
3716 
3717   MacroAssembler _masm(&cb);
3718   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3719 
3720   for (uint i = 0; i < n->outcnt(); i++) {
3721     address* constant_addr = &jump_table_base[i];
3722     assert(*constant_addr == (((address) n) + i), err_msg_res("all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, *constant_addr, (((address) n) + i)));
3723     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3724     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3725   }
3726 }
3727 
3728 void Compile::dump_inlining() {
3729   if (print_inlining() || print_intrinsics()) {
3730     // Print inlining message for candidates that we couldn't inline
3731     // for lack of space or non constant receiver
3732     for (int i = 0; i < _late_inlines.length(); i++) {
3733       CallGenerator* cg = _late_inlines.at(i);
3734       cg->print_inlining_late("live nodes > LiveNodeCountInliningCutoff");
3735     }
3736     Unique_Node_List useful;
3737     useful.push(root());
3738     for (uint next = 0; next < useful.size(); ++next) {
3739       Node* n  = useful.at(next);
3740       if (n->is_Call() && n->as_Call()->generator() != NULL && n->as_Call()->generator()->call_node() == n) {
3741         CallNode* call = n->as_Call();
3742         CallGenerator* cg = call->generator();
3743         cg->print_inlining_late("receiver not constant");
3744       }
3745       uint max = n->len();
3746       for ( uint i = 0; i < max; ++i ) {
3747         Node *m = n->in(i);
3748         if ( m == NULL ) continue;
3749         useful.push(m);
3750       }
3751     }
3752     for (int i = 0; i < _print_inlining_list->length(); i++) {
3753       tty->print(_print_inlining_list->adr_at(i)->ss()->as_string());
3754     }
3755   }
3756 }
3757 
3758 // Dump inlining replay data to the stream.
3759 // Don't change thread state and acquire any locks.
3760 void Compile::dump_inline_data(outputStream* out) {
3761   InlineTree* inl_tree = ilt();
3762   if (inl_tree != NULL) {
3763     out->print(" inline %d", inl_tree->count());
3764     inl_tree->dump_replay_data(out);
3765   }
3766 }
3767 
3768 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3769   if (n1->Opcode() < n2->Opcode())      return -1;
3770   else if (n1->Opcode() > n2->Opcode()) return 1;
3771 
3772   assert(n1->req() == n2->req(), err_msg_res("can't compare %s nodes: n1->req() = %d, n2->req() = %d", NodeClassNames[n1->Opcode()], n1->req(), n2->req()));
3773   for (uint i = 1; i < n1->req(); i++) {
3774     if (n1->in(i) < n2->in(i))      return -1;
3775     else if (n1->in(i) > n2->in(i)) return 1;
3776   }
3777 
3778   return 0;
3779 }
3780 
3781 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3782   Node* n1 = *n1p;
3783   Node* n2 = *n2p;
3784 
3785   return cmp_expensive_nodes(n1, n2);
3786 }
3787 
3788 void Compile::sort_expensive_nodes() {
3789   if (!expensive_nodes_sorted()) {
3790     _expensive_nodes->sort(cmp_expensive_nodes);
3791   }
3792 }
3793 
3794 bool Compile::expensive_nodes_sorted() const {
3795   for (int i = 1; i < _expensive_nodes->length(); i++) {
3796     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
3797       return false;
3798     }
3799   }
3800   return true;
3801 }
3802 
3803 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
3804   if (_expensive_nodes->length() == 0) {
3805     return false;
3806   }
3807 
3808   assert(OptimizeExpensiveOps, "optimization off?");
3809 
3810   // Take this opportunity to remove dead nodes from the list
3811   int j = 0;
3812   for (int i = 0; i < _expensive_nodes->length(); i++) {
3813     Node* n = _expensive_nodes->at(i);
3814     if (!n->is_unreachable(igvn)) {
3815       assert(n->is_expensive(), "should be expensive");
3816       _expensive_nodes->at_put(j, n);
3817       j++;
3818     }
3819   }
3820   _expensive_nodes->trunc_to(j);
3821 
3822   // Then sort the list so that similar nodes are next to each other
3823   // and check for at least two nodes of identical kind with same data
3824   // inputs.
3825   sort_expensive_nodes();
3826 
3827   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
3828     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
3829       return true;
3830     }
3831   }
3832 
3833   return false;
3834 }
3835 
3836 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
3837   if (_expensive_nodes->length() == 0) {
3838     return;
3839   }
3840 
3841   assert(OptimizeExpensiveOps, "optimization off?");
3842 
3843   // Sort to bring similar nodes next to each other and clear the
3844   // control input of nodes for which there's only a single copy.
3845   sort_expensive_nodes();
3846 
3847   int j = 0;
3848   int identical = 0;
3849   int i = 0;
3850   for (; i < _expensive_nodes->length()-1; i++) {
3851     assert(j <= i, "can't write beyond current index");
3852     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
3853       identical++;
3854       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3855       continue;
3856     }
3857     if (identical > 0) {
3858       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3859       identical = 0;
3860     } else {
3861       Node* n = _expensive_nodes->at(i);
3862       igvn.hash_delete(n);
3863       n->set_req(0, NULL);
3864       igvn.hash_insert(n);
3865     }
3866   }
3867   if (identical > 0) {
3868     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3869   } else if (_expensive_nodes->length() >= 1) {
3870     Node* n = _expensive_nodes->at(i);
3871     igvn.hash_delete(n);
3872     n->set_req(0, NULL);
3873     igvn.hash_insert(n);
3874   }
3875   _expensive_nodes->trunc_to(j);
3876 }
3877 
3878 void Compile::add_expensive_node(Node * n) {
3879   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
3880   assert(n->is_expensive(), "expensive nodes with non-null control here only");
3881   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
3882   if (OptimizeExpensiveOps) {
3883     _expensive_nodes->append(n);
3884   } else {
3885     // Clear control input and let IGVN optimize expensive nodes if
3886     // OptimizeExpensiveOps is off.
3887     n->set_req(0, NULL);
3888   }
3889 }
3890 
3891 /**
3892  * Remove the speculative part of types and clean up the graph
3893  */
3894 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
3895   if (UseTypeSpeculation) {
3896     Unique_Node_List worklist;
3897     worklist.push(root());
3898     int modified = 0;
3899     // Go over all type nodes that carry a speculative type, drop the
3900     // speculative part of the type and enqueue the node for an igvn
3901     // which may optimize it out.
3902     for (uint next = 0; next < worklist.size(); ++next) {
3903       Node *n  = worklist.at(next);
3904       if (n->is_Type()) {
3905         TypeNode* tn = n->as_Type();
3906         const Type* t = tn->type();
3907         const Type* t_no_spec = t->remove_speculative();
3908         if (t_no_spec != t) {
3909           bool in_hash = igvn.hash_delete(n);
3910           assert(in_hash, "node should be in igvn hash table");
3911           tn->set_type(t_no_spec);
3912           igvn.hash_insert(n);
3913           igvn._worklist.push(n); // give it a chance to go away
3914           modified++;
3915         }
3916       }
3917       uint max = n->len();
3918       for( uint i = 0; i < max; ++i ) {
3919         Node *m = n->in(i);
3920         if (not_a_node(m))  continue;
3921         worklist.push(m);
3922       }
3923     }
3924     // Drop the speculative part of all types in the igvn's type table
3925     igvn.remove_speculative_types();
3926     if (modified > 0) {
3927       igvn.optimize();
3928     }
3929 #ifdef ASSERT
3930     // Verify that after the IGVN is over no speculative type has resurfaced
3931     worklist.clear();
3932     worklist.push(root());
3933     for (uint next = 0; next < worklist.size(); ++next) {
3934       Node *n  = worklist.at(next);
3935       const Type* t = igvn.type(n);
3936       assert(t == t->remove_speculative(), "no more speculative types");
3937       if (n->is_Type()) {
3938         t = n->as_Type()->type();
3939         assert(t == t->remove_speculative(), "no more speculative types");
3940       }
3941       uint max = n->len();
3942       for( uint i = 0; i < max; ++i ) {
3943         Node *m = n->in(i);
3944         if (not_a_node(m))  continue;
3945         worklist.push(m);
3946       }
3947     }
3948     igvn.check_no_speculative_types();
3949 #endif
3950   }
3951 }
3952 
3953 // Auxiliary method to support randomized stressing/fuzzing.
3954 //
3955 // This method can be called the arbitrary number of times, with current count
3956 // as the argument. The logic allows selecting a single candidate from the
3957 // running list of candidates as follows:
3958 //    int count = 0;
3959 //    Cand* selected = null;
3960 //    while(cand = cand->next()) {
3961 //      if (randomized_select(++count)) {
3962 //        selected = cand;
3963 //      }
3964 //    }
3965 //
3966 // Including count equalizes the chances any candidate is "selected".
3967 // This is useful when we don't have the complete list of candidates to choose
3968 // from uniformly. In this case, we need to adjust the randomicity of the
3969 // selection, or else we will end up biasing the selection towards the latter
3970 // candidates.
3971 //
3972 // Quick back-envelope calculation shows that for the list of n candidates
3973 // the equal probability for the candidate to persist as "best" can be
3974 // achieved by replacing it with "next" k-th candidate with the probability
3975 // of 1/k. It can be easily shown that by the end of the run, the
3976 // probability for any candidate is converged to 1/n, thus giving the
3977 // uniform distribution among all the candidates.
3978 //
3979 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
3980 #define RANDOMIZED_DOMAIN_POW 29
3981 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
3982 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
3983 bool Compile::randomized_select(int count) {
3984   assert(count > 0, "only positive");
3985   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
3986 }