1 /*
   2  * Copyright (c) 1997, 2014, 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/narrowptrnode.hpp"
  55 #include "opto/node.hpp"
  56 #include "opto/opcodes.hpp"
  57 #include "opto/output.hpp"
  58 #include "opto/parse.hpp"
  59 #include "opto/phaseX.hpp"
  60 #include "opto/rootnode.hpp"
  61 #include "opto/runtime.hpp"
  62 #include "opto/stringopts.hpp"
  63 #include "opto/type.hpp"
  64 #include "opto/vectornode.hpp"
  65 #include "runtime/arguments.hpp"
  66 #include "runtime/signature.hpp"
  67 #include "runtime/stubRoutines.hpp"
  68 #include "runtime/timer.hpp"
  69 #include "trace/tracing.hpp"
  70 #include "utilities/copy.hpp"
  71 #ifdef TARGET_ARCH_MODEL_x86_32
  72 # include "adfiles/ad_x86_32.hpp"
  73 #endif
  74 #ifdef TARGET_ARCH_MODEL_x86_64
  75 # include "adfiles/ad_x86_64.hpp"
  76 #endif
  77 #ifdef TARGET_ARCH_MODEL_sparc
  78 # include "adfiles/ad_sparc.hpp"
  79 #endif
  80 #ifdef TARGET_ARCH_MODEL_zero
  81 # include "adfiles/ad_zero.hpp"
  82 #endif
  83 #ifdef TARGET_ARCH_MODEL_arm
  84 # include "adfiles/ad_arm.hpp"
  85 #endif
  86 #ifdef TARGET_ARCH_MODEL_ppc_32
  87 # include "adfiles/ad_ppc_32.hpp"
  88 #endif
  89 #ifdef TARGET_ARCH_MODEL_ppc_64
  90 # include "adfiles/ad_ppc_64.hpp"
  91 #endif
  92 
  93 
  94 // -------------------- Compile::mach_constant_base_node -----------------------
  95 // Constant table base node singleton.
  96 MachConstantBaseNode* Compile::mach_constant_base_node() {
  97   if (_mach_constant_base_node == NULL) {
  98     _mach_constant_base_node = new MachConstantBaseNode();
  99     _mach_constant_base_node->add_req(C->root());
 100   }
 101   return _mach_constant_base_node;
 102 }
 103 
 104 
 105 /// Support for intrinsics.
 106 
 107 // Return the index at which m must be inserted (or already exists).
 108 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 109 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
 110 #ifdef ASSERT
 111   for (int i = 1; i < _intrinsics->length(); i++) {
 112     CallGenerator* cg1 = _intrinsics->at(i-1);
 113     CallGenerator* cg2 = _intrinsics->at(i);
 114     assert(cg1->method() != cg2->method()
 115            ? cg1->method()     < cg2->method()
 116            : cg1->is_virtual() < cg2->is_virtual(),
 117            "compiler intrinsics list must stay sorted");
 118   }
 119 #endif
 120   // Binary search sorted list, in decreasing intervals [lo, hi].
 121   int lo = 0, hi = _intrinsics->length()-1;
 122   while (lo <= hi) {
 123     int mid = (uint)(hi + lo) / 2;
 124     ciMethod* mid_m = _intrinsics->at(mid)->method();
 125     if (m < mid_m) {
 126       hi = mid-1;
 127     } else if (m > mid_m) {
 128       lo = mid+1;
 129     } else {
 130       // look at minor sort key
 131       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 132       if (is_virtual < mid_virt) {
 133         hi = mid-1;
 134       } else if (is_virtual > mid_virt) {
 135         lo = mid+1;
 136       } else {
 137         return mid;  // exact match
 138       }
 139     }
 140   }
 141   return lo;  // inexact match
 142 }
 143 
 144 void Compile::register_intrinsic(CallGenerator* cg) {
 145   if (_intrinsics == NULL) {
 146     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 147   }
 148   // This code is stolen from ciObjectFactory::insert.
 149   // Really, GrowableArray should have methods for
 150   // insert_at, remove_at, and binary_search.
 151   int len = _intrinsics->length();
 152   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 153   if (index == len) {
 154     _intrinsics->append(cg);
 155   } else {
 156 #ifdef ASSERT
 157     CallGenerator* oldcg = _intrinsics->at(index);
 158     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 159 #endif
 160     _intrinsics->append(_intrinsics->at(len-1));
 161     int pos;
 162     for (pos = len-2; pos >= index; pos--) {
 163       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 164     }
 165     _intrinsics->at_put(index, cg);
 166   }
 167   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 168 }
 169 
 170 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 171   assert(m->is_loaded(), "don't try this on unloaded methods");
 172   if (_intrinsics != NULL) {
 173     int index = intrinsic_insertion_index(m, is_virtual);
 174     if (index < _intrinsics->length()
 175         && _intrinsics->at(index)->method() == m
 176         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 177       return _intrinsics->at(index);
 178     }
 179   }
 180   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 181   if (m->intrinsic_id() != vmIntrinsics::_none &&
 182       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 183     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 184     if (cg != NULL) {
 185       // Save it for next time:
 186       register_intrinsic(cg);
 187       return cg;
 188     } else {
 189       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 190     }
 191   }
 192   return NULL;
 193 }
 194 
 195 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 196 // in library_call.cpp.
 197 
 198 
 199 #ifndef PRODUCT
 200 // statistics gathering...
 201 
 202 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 203 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 204 
 205 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 206   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 207   int oflags = _intrinsic_hist_flags[id];
 208   assert(flags != 0, "what happened?");
 209   if (is_virtual) {
 210     flags |= _intrinsic_virtual;
 211   }
 212   bool changed = (flags != oflags);
 213   if ((flags & _intrinsic_worked) != 0) {
 214     juint count = (_intrinsic_hist_count[id] += 1);
 215     if (count == 1) {
 216       changed = true;           // first time
 217     }
 218     // increment the overall count also:
 219     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 220   }
 221   if (changed) {
 222     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 223       // Something changed about the intrinsic's virtuality.
 224       if ((flags & _intrinsic_virtual) != 0) {
 225         // This is the first use of this intrinsic as a virtual call.
 226         if (oflags != 0) {
 227           // We already saw it as a non-virtual, so note both cases.
 228           flags |= _intrinsic_both;
 229         }
 230       } else if ((oflags & _intrinsic_both) == 0) {
 231         // This is the first use of this intrinsic as a non-virtual
 232         flags |= _intrinsic_both;
 233       }
 234     }
 235     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 236   }
 237   // update the overall flags also:
 238   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 239   return changed;
 240 }
 241 
 242 static char* format_flags(int flags, char* buf) {
 243   buf[0] = 0;
 244   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 245   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 246   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 247   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 248   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 249   if (buf[0] == 0)  strcat(buf, ",");
 250   assert(buf[0] == ',', "must be");
 251   return &buf[1];
 252 }
 253 
 254 void Compile::print_intrinsic_statistics() {
 255   char flagsbuf[100];
 256   ttyLocker ttyl;
 257   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 258   tty->print_cr("Compiler intrinsic usage:");
 259   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 260   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 261   #define PRINT_STAT_LINE(name, c, f) \
 262     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 263   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 264     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 265     int   flags = _intrinsic_hist_flags[id];
 266     juint count = _intrinsic_hist_count[id];
 267     if ((flags | count) != 0) {
 268       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 269     }
 270   }
 271   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 272   if (xtty != NULL)  xtty->tail("statistics");
 273 }
 274 
 275 void Compile::print_statistics() {
 276   { ttyLocker ttyl;
 277     if (xtty != NULL)  xtty->head("statistics type='opto'");
 278     Parse::print_statistics();
 279     PhaseCCP::print_statistics();
 280     PhaseRegAlloc::print_statistics();
 281     Scheduling::print_statistics();
 282     PhasePeephole::print_statistics();
 283     PhaseIdealLoop::print_statistics();
 284     if (xtty != NULL)  xtty->tail("statistics");
 285   }
 286   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 287     // put this under its own <statistics> element.
 288     print_intrinsic_statistics();
 289   }
 290 }
 291 #endif //PRODUCT
 292 
 293 // Support for bundling info
 294 Bundle* Compile::node_bundling(const Node *n) {
 295   assert(valid_bundle_info(n), "oob");
 296   return &_node_bundling_base[n->_idx];
 297 }
 298 
 299 bool Compile::valid_bundle_info(const Node *n) {
 300   return (_node_bundling_limit > n->_idx);
 301 }
 302 
 303 
 304 void Compile::gvn_replace_by(Node* n, Node* nn) {
 305   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 306     Node* use = n->last_out(i);
 307     bool is_in_table = initial_gvn()->hash_delete(use);
 308     uint uses_found = 0;
 309     for (uint j = 0; j < use->len(); j++) {
 310       if (use->in(j) == n) {
 311         if (j < use->req())
 312           use->set_req(j, nn);
 313         else
 314           use->set_prec(j, nn);
 315         uses_found++;
 316       }
 317     }
 318     if (is_in_table) {
 319       // reinsert into table
 320       initial_gvn()->hash_find_insert(use);
 321     }
 322     record_for_igvn(use);
 323     i -= uses_found;    // we deleted 1 or more copies of this edge
 324   }
 325 }
 326 
 327 
 328 static inline bool not_a_node(const Node* n) {
 329   if (n == NULL)                   return true;
 330   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 331   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 332   return false;
 333 }
 334 
 335 // Identify all nodes that are reachable from below, useful.
 336 // Use breadth-first pass that records state in a Unique_Node_List,
 337 // recursive traversal is slower.
 338 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 339   int estimated_worklist_size = unique();
 340   useful.map( estimated_worklist_size, NULL );  // preallocate space
 341 
 342   // Initialize worklist
 343   if (root() != NULL)     { useful.push(root()); }
 344   // If 'top' is cached, declare it useful to preserve cached node
 345   if( cached_top_node() ) { useful.push(cached_top_node()); }
 346 
 347   // Push all useful nodes onto the list, breadthfirst
 348   for( uint next = 0; next < useful.size(); ++next ) {
 349     assert( next < unique(), "Unique useful nodes < total nodes");
 350     Node *n  = useful.at(next);
 351     uint max = n->len();
 352     for( uint i = 0; i < max; ++i ) {
 353       Node *m = n->in(i);
 354       if (not_a_node(m))  continue;
 355       useful.push(m);
 356     }
 357   }
 358 }
 359 
 360 // Update dead_node_list with any missing dead nodes using useful
 361 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 362 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 363   uint max_idx = unique();
 364   VectorSet& useful_node_set = useful.member_set();
 365 
 366   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 367     // If node with index node_idx is not in useful set,
 368     // mark it as dead in dead node list.
 369     if (! useful_node_set.test(node_idx) ) {
 370       record_dead_node(node_idx);
 371     }
 372   }
 373 }
 374 
 375 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 376   int shift = 0;
 377   for (int i = 0; i < inlines->length(); i++) {
 378     CallGenerator* cg = inlines->at(i);
 379     CallNode* call = cg->call_node();
 380     if (shift > 0) {
 381       inlines->at_put(i-shift, cg);
 382     }
 383     if (!useful.member(call)) {
 384       shift++;
 385     }
 386   }
 387   inlines->trunc_to(inlines->length()-shift);
 388 }
 389 
 390 // Disconnect all useless nodes by disconnecting those at the boundary.
 391 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 392   uint next = 0;
 393   while (next < useful.size()) {
 394     Node *n = useful.at(next++);
 395     // Use raw traversal of out edges since this code removes out edges
 396     int max = n->outcnt();
 397     for (int j = 0; j < max; ++j) {
 398       Node* child = n->raw_out(j);
 399       if (! useful.member(child)) {
 400         assert(!child->is_top() || child != top(),
 401                "If top is cached in Compile object it is in useful list");
 402         // Only need to remove this out-edge to the useless node
 403         n->raw_del_out(j);
 404         --j;
 405         --max;
 406       }
 407     }
 408     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 409       record_for_igvn(n->unique_out());
 410     }
 411   }
 412   // Remove useless macro and predicate opaq nodes
 413   for (int i = C->macro_count()-1; i >= 0; i--) {
 414     Node* n = C->macro_node(i);
 415     if (!useful.member(n)) {
 416       remove_macro_node(n);
 417     }
 418   }
 419   // Remove useless expensive node
 420   for (int i = C->expensive_count()-1; i >= 0; i--) {
 421     Node* n = C->expensive_node(i);
 422     if (!useful.member(n)) {
 423       remove_expensive_node(n);
 424     }
 425   }
 426   // clean up the late inline lists
 427   remove_useless_late_inlines(&_string_late_inlines, useful);
 428   remove_useless_late_inlines(&_boxing_late_inlines, useful);
 429   remove_useless_late_inlines(&_late_inlines, useful);
 430   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 431 }
 432 
 433 //------------------------------frame_size_in_words-----------------------------
 434 // frame_slots in units of words
 435 int Compile::frame_size_in_words() const {
 436   // shift is 0 in LP32 and 1 in LP64
 437   const int shift = (LogBytesPerWord - LogBytesPerInt);
 438   int words = _frame_slots >> shift;
 439   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 440   return words;
 441 }
 442 
 443 // To bang the stack of this compiled method we use the stack size
 444 // that the interpreter would need in case of a deoptimization. This
 445 // removes the need to bang the stack in the deoptimization blob which
 446 // in turn simplifies stack overflow handling.
 447 int Compile::bang_size_in_bytes() const {
 448   return MAX2(_interpreter_frame_size, frame_size_in_bytes());
 449 }
 450 
 451 // ============================================================================
 452 //------------------------------CompileWrapper---------------------------------
 453 class CompileWrapper : public StackObj {
 454   Compile *const _compile;
 455  public:
 456   CompileWrapper(Compile* compile);
 457 
 458   ~CompileWrapper();
 459 };
 460 
 461 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 462   // the Compile* pointer is stored in the current ciEnv:
 463   ciEnv* env = compile->env();
 464   assert(env == ciEnv::current(), "must already be a ciEnv active");
 465   assert(env->compiler_data() == NULL, "compile already active?");
 466   env->set_compiler_data(compile);
 467   assert(compile == Compile::current(), "sanity");
 468 
 469   compile->set_type_dict(NULL);
 470   compile->set_type_hwm(NULL);
 471   compile->set_type_last_size(0);
 472   compile->set_last_tf(NULL, NULL);
 473   compile->set_indexSet_arena(NULL);
 474   compile->set_indexSet_free_block_list(NULL);
 475   compile->init_type_arena();
 476   Type::Initialize(compile);
 477   _compile->set_scratch_buffer_blob(NULL);
 478   _compile->begin_method();
 479 }
 480 CompileWrapper::~CompileWrapper() {
 481   _compile->end_method();
 482   if (_compile->scratch_buffer_blob() != NULL)
 483     BufferBlob::free(_compile->scratch_buffer_blob());
 484   _compile->env()->set_compiler_data(NULL);
 485 }
 486 
 487 
 488 //----------------------------print_compile_messages---------------------------
 489 void Compile::print_compile_messages() {
 490 #ifndef PRODUCT
 491   // Check if recompiling
 492   if (_subsume_loads == false && PrintOpto) {
 493     // Recompiling without allowing machine instructions to subsume loads
 494     tty->print_cr("*********************************************************");
 495     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 496     tty->print_cr("*********************************************************");
 497   }
 498   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 499     // Recompiling without escape analysis
 500     tty->print_cr("*********************************************************");
 501     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 502     tty->print_cr("*********************************************************");
 503   }
 504   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 505     // Recompiling without boxing elimination
 506     tty->print_cr("*********************************************************");
 507     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 508     tty->print_cr("*********************************************************");
 509   }
 510   if (env()->break_at_compile()) {
 511     // Open the debugger when compiling this method.
 512     tty->print("### Breaking when compiling: ");
 513     method()->print_short_name();
 514     tty->cr();
 515     BREAKPOINT;
 516   }
 517 
 518   if( PrintOpto ) {
 519     if (is_osr_compilation()) {
 520       tty->print("[OSR]%3d", _compile_id);
 521     } else {
 522       tty->print("%3d", _compile_id);
 523     }
 524   }
 525 #endif
 526 }
 527 
 528 
 529 //-----------------------init_scratch_buffer_blob------------------------------
 530 // Construct a temporary BufferBlob and cache it for this compile.
 531 void Compile::init_scratch_buffer_blob(int const_size) {
 532   // If there is already a scratch buffer blob allocated and the
 533   // constant section is big enough, use it.  Otherwise free the
 534   // current and allocate a new one.
 535   BufferBlob* blob = scratch_buffer_blob();
 536   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 537     // Use the current blob.
 538   } else {
 539     if (blob != NULL) {
 540       BufferBlob::free(blob);
 541     }
 542 
 543     ResourceMark rm;
 544     _scratch_const_size = const_size;
 545     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 546     blob = BufferBlob::create("Compile::scratch_buffer", size);
 547     // Record the buffer blob for next time.
 548     set_scratch_buffer_blob(blob);
 549     // Have we run out of code space?
 550     if (scratch_buffer_blob() == NULL) {
 551       // Let CompilerBroker disable further compilations.
 552       record_failure("Not enough space for scratch buffer in CodeCache");
 553       return;
 554     }
 555   }
 556 
 557   // Initialize the relocation buffers
 558   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 559   set_scratch_locs_memory(locs_buf);
 560 }
 561 
 562 
 563 //-----------------------scratch_emit_size-------------------------------------
 564 // Helper function that computes size by emitting code
 565 uint Compile::scratch_emit_size(const Node* n) {
 566   // Start scratch_emit_size section.
 567   set_in_scratch_emit_size(true);
 568 
 569   // Emit into a trash buffer and count bytes emitted.
 570   // This is a pretty expensive way to compute a size,
 571   // but it works well enough if seldom used.
 572   // All common fixed-size instructions are given a size
 573   // method by the AD file.
 574   // Note that the scratch buffer blob and locs memory are
 575   // allocated at the beginning of the compile task, and
 576   // may be shared by several calls to scratch_emit_size.
 577   // The allocation of the scratch buffer blob is particularly
 578   // expensive, since it has to grab the code cache lock.
 579   BufferBlob* blob = this->scratch_buffer_blob();
 580   assert(blob != NULL, "Initialize BufferBlob at start");
 581   assert(blob->size() > MAX_inst_size, "sanity");
 582   relocInfo* locs_buf = scratch_locs_memory();
 583   address blob_begin = blob->content_begin();
 584   address blob_end   = (address)locs_buf;
 585   assert(blob->content_contains(blob_end), "sanity");
 586   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 587   buf.initialize_consts_size(_scratch_const_size);
 588   buf.initialize_stubs_size(MAX_stubs_size);
 589   assert(locs_buf != NULL, "sanity");
 590   int lsize = MAX_locs_size / 3;
 591   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 592   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 593   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 594 
 595   // Do the emission.
 596 
 597   Label fakeL; // Fake label for branch instructions.
 598   Label*   saveL = NULL;
 599   uint save_bnum = 0;
 600   bool is_branch = n->is_MachBranch();
 601   if (is_branch) {
 602     MacroAssembler masm(&buf);
 603     masm.bind(fakeL);
 604     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 605     n->as_MachBranch()->label_set(&fakeL, 0);
 606   }
 607   n->emit(buf, this->regalloc());
 608   if (is_branch) // Restore label.
 609     n->as_MachBranch()->label_set(saveL, save_bnum);
 610 
 611   // End scratch_emit_size section.
 612   set_in_scratch_emit_size(false);
 613 
 614   return buf.insts_size();
 615 }
 616 
 617 
 618 // ============================================================================
 619 //------------------------------Compile standard-------------------------------
 620 debug_only( int Compile::_debug_idx = 100000; )
 621 
 622 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 623 // the continuation bci for on stack replacement.
 624 
 625 
 626 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 627                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
 628                 : Phase(Compiler),
 629                   _env(ci_env),
 630                   _log(ci_env->log()),
 631                   _compile_id(ci_env->compile_id()),
 632                   _save_argument_registers(false),
 633                   _stub_name(NULL),
 634                   _stub_function(NULL),
 635                   _stub_entry_point(NULL),
 636                   _method(target),
 637                   _entry_bci(osr_bci),
 638                   _initial_gvn(NULL),
 639                   _for_igvn(NULL),
 640                   _warm_calls(NULL),
 641                   _subsume_loads(subsume_loads),
 642                   _do_escape_analysis(do_escape_analysis),
 643                   _eliminate_boxing(eliminate_boxing),
 644                   _failure_reason(NULL),
 645                   _code_buffer("Compile::Fill_buffer"),
 646                   _orig_pc_slot(0),
 647                   _orig_pc_slot_offset_in_bytes(0),
 648                   _has_method_handle_invokes(false),
 649                   _mach_constant_base_node(NULL),
 650                   _node_bundling_limit(0),
 651                   _node_bundling_base(NULL),
 652                   _java_calls(0),
 653                   _inner_loops(0),
 654                   _scratch_const_size(-1),
 655                   _in_scratch_emit_size(false),
 656                   _dead_node_list(comp_arena()),
 657                   _dead_node_count(0),
 658 #ifndef PRODUCT
 659                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 660                   _in_dump_cnt(0),
 661                   _printer(IdealGraphPrinter::printer()),
 662 #endif
 663                   _congraph(NULL),
 664                   _replay_inline_data(NULL),
 665                   _late_inlines(comp_arena(), 2, 0, NULL),
 666                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 667                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 668                   _late_inlines_pos(0),
 669                   _number_of_mh_late_inlines(0),
 670                   _inlining_progress(false),
 671                   _inlining_incrementally(false),
 672                   _print_inlining_list(NULL),
 673                   _print_inlining_stream(NULL),
 674                   _print_inlining_idx(0),
 675                   _print_inlining_output(NULL),
 676                   _preserve_jvm_state(0),
 677                   _interpreter_frame_size(0) {
 678   C = this;
 679 
 680   CompileWrapper cw(this);
 681 #ifndef PRODUCT
 682   if (TimeCompiler2) {
 683     tty->print(" ");
 684     target->holder()->name()->print();
 685     tty->print(".");
 686     target->print_short_name();
 687     tty->print("  ");
 688   }
 689   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 690   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 691   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 692   if (!print_opto_assembly) {
 693     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 694     if (print_assembly && !Disassembler::can_decode()) {
 695       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 696       print_opto_assembly = true;
 697     }
 698   }
 699   set_print_assembly(print_opto_assembly);
 700   set_parsed_irreducible_loop(false);
 701 
 702   if (method()->has_option("ReplayInline")) {
 703     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 704   }
 705 #endif
 706   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
 707   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
 708   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 709 
 710   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 711     // Make sure the method being compiled gets its own MDO,
 712     // so we can at least track the decompile_count().
 713     // Need MDO to record RTM code generation state.
 714     method()->ensure_method_data();
 715   }
 716 
 717   Init(::AliasLevel);
 718 
 719 
 720   print_compile_messages();
 721 
 722   _ilt = InlineTree::build_inline_tree_root();
 723 
 724   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 725   assert(num_alias_types() >= AliasIdxRaw, "");
 726 
 727 #define MINIMUM_NODE_HASH  1023
 728   // Node list that Iterative GVN will start with
 729   Unique_Node_List for_igvn(comp_arena());
 730   set_for_igvn(&for_igvn);
 731 
 732   // GVN that will be run immediately on new nodes
 733   uint estimated_size = method()->code_size()*4+64;
 734   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 735   PhaseGVN gvn(node_arena(), estimated_size);
 736   set_initial_gvn(&gvn);
 737 
 738   print_inlining_init();
 739   { // Scope for timing the parser
 740     TracePhase t3("parse", &_t_parser, true);
 741 
 742     // Put top into the hash table ASAP.
 743     initial_gvn()->transform_no_reclaim(top());
 744 
 745     // Set up tf(), start(), and find a CallGenerator.
 746     CallGenerator* cg = NULL;
 747     if (is_osr_compilation()) {
 748       const TypeTuple *domain = StartOSRNode::osr_domain();
 749       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 750       init_tf(TypeFunc::make(domain, range));
 751       StartNode* s = new StartOSRNode(root(), domain);
 752       initial_gvn()->set_type_bottom(s);
 753       init_start(s);
 754       cg = CallGenerator::for_osr(method(), entry_bci());
 755     } else {
 756       // Normal case.
 757       init_tf(TypeFunc::make(method()));
 758       StartNode* s = new StartNode(root(), tf()->domain());
 759       initial_gvn()->set_type_bottom(s);
 760       init_start(s);
 761       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 762         // With java.lang.ref.reference.get() we must go through the
 763         // intrinsic when G1 is enabled - even when get() is the root
 764         // method of the compile - so that, if necessary, the value in
 765         // the referent field of the reference object gets recorded by
 766         // the pre-barrier code.
 767         // Specifically, if G1 is enabled, the value in the referent
 768         // field is recorded by the G1 SATB pre barrier. This will
 769         // result in the referent being marked live and the reference
 770         // object removed from the list of discovered references during
 771         // reference processing.
 772         cg = find_intrinsic(method(), false);
 773       }
 774       if (cg == NULL) {
 775         float past_uses = method()->interpreter_invocation_count();
 776         float expected_uses = past_uses;
 777         cg = CallGenerator::for_inline(method(), expected_uses);
 778       }
 779     }
 780     if (failing())  return;
 781     if (cg == NULL) {
 782       record_method_not_compilable_all_tiers("cannot parse method");
 783       return;
 784     }
 785     JVMState* jvms = build_start_state(start(), tf());
 786     if ((jvms = cg->generate(jvms, NULL)) == NULL) {
 787       record_method_not_compilable("method parse failed");
 788       return;
 789     }
 790     GraphKit kit(jvms);
 791 
 792     if (!kit.stopped()) {
 793       // Accept return values, and transfer control we know not where.
 794       // This is done by a special, unique ReturnNode bound to root.
 795       return_values(kit.jvms());
 796     }
 797 
 798     if (kit.has_exceptions()) {
 799       // Any exceptions that escape from this call must be rethrown
 800       // to whatever caller is dynamically above us on the stack.
 801       // This is done by a special, unique RethrowNode bound to root.
 802       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 803     }
 804 
 805     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 806 
 807     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 808       inline_string_calls(true);
 809     }
 810 
 811     if (failing())  return;
 812 
 813     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 814 
 815     // Remove clutter produced by parsing.
 816     if (!failing()) {
 817       ResourceMark rm;
 818       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 819     }
 820   }
 821 
 822   // Note:  Large methods are capped off in do_one_bytecode().
 823   if (failing())  return;
 824 
 825   // After parsing, node notes are no longer automagic.
 826   // They must be propagated by register_new_node_with_optimizer(),
 827   // clone(), or the like.
 828   set_default_node_notes(NULL);
 829 
 830   for (;;) {
 831     int successes = Inline_Warm();
 832     if (failing())  return;
 833     if (successes == 0)  break;
 834   }
 835 
 836   // Drain the list.
 837   Finish_Warm();
 838 #ifndef PRODUCT
 839   if (_printer) {
 840     _printer->print_inlining(this);
 841   }
 842 #endif
 843 
 844   if (failing())  return;
 845   NOT_PRODUCT( verify_graph_edges(); )
 846 
 847   // Now optimize
 848   Optimize();
 849   if (failing())  return;
 850   NOT_PRODUCT( verify_graph_edges(); )
 851 
 852 #ifndef PRODUCT
 853   if (PrintIdeal) {
 854     ttyLocker ttyl;  // keep the following output all in one block
 855     // This output goes directly to the tty, not the compiler log.
 856     // To enable tools to match it up with the compilation activity,
 857     // be sure to tag this tty output with the compile ID.
 858     if (xtty != NULL) {
 859       xtty->head("ideal compile_id='%d'%s", compile_id(),
 860                  is_osr_compilation()    ? " compile_kind='osr'" :
 861                  "");
 862     }
 863     root()->dump(9999);
 864     if (xtty != NULL) {
 865       xtty->tail("ideal");
 866     }
 867   }
 868 #endif
 869 
 870   NOT_PRODUCT( verify_barriers(); )
 871 
 872   // Dump compilation data to replay it.
 873   if (method()->has_option("DumpReplay")) {
 874     env()->dump_replay_data(_compile_id);
 875   }
 876   if (method()->has_option("DumpInline") && (ilt() != NULL)) {
 877     env()->dump_inline_data(_compile_id);
 878   }
 879 
 880   // Now that we know the size of all the monitors we can add a fixed slot
 881   // for the original deopt pc.
 882 
 883   _orig_pc_slot =  fixed_slots();
 884   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 885   set_fixed_slots(next_slot);
 886 
 887   // Compute when to use implicit null checks. Used by matching trap based
 888   // nodes and NullCheck optimization.
 889   set_allowed_deopt_reasons();
 890 
 891   // Now generate code
 892   Code_Gen();
 893   if (failing())  return;
 894 
 895   // Check if we want to skip execution of all compiled code.
 896   {
 897 #ifndef PRODUCT
 898     if (OptoNoExecute) {
 899       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 900       return;
 901     }
 902     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 903 #endif
 904 
 905     if (is_osr_compilation()) {
 906       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 907       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 908     } else {
 909       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 910       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 911     }
 912 
 913     env()->register_method(_method, _entry_bci,
 914                            &_code_offsets,
 915                            _orig_pc_slot_offset_in_bytes,
 916                            code_buffer(),
 917                            frame_size_in_words(), _oop_map_set,
 918                            &_handler_table, &_inc_table,
 919                            compiler,
 920                            env()->comp_level(),
 921                            has_unsafe_access(),
 922                            SharedRuntime::is_wide_vector(max_vector_size()),
 923                            rtm_state()
 924                            );
 925 
 926     if (log() != NULL) // Print code cache state into compiler log
 927       log()->code_cache_state();
 928   }
 929 }
 930 
 931 //------------------------------Compile----------------------------------------
 932 // Compile a runtime stub
 933 Compile::Compile( ciEnv* ci_env,
 934                   TypeFunc_generator generator,
 935                   address stub_function,
 936                   const char *stub_name,
 937                   int is_fancy_jump,
 938                   bool pass_tls,
 939                   bool save_arg_registers,
 940                   bool return_pc )
 941   : Phase(Compiler),
 942     _env(ci_env),
 943     _log(ci_env->log()),
 944     _compile_id(0),
 945     _save_argument_registers(save_arg_registers),
 946     _method(NULL),
 947     _stub_name(stub_name),
 948     _stub_function(stub_function),
 949     _stub_entry_point(NULL),
 950     _entry_bci(InvocationEntryBci),
 951     _initial_gvn(NULL),
 952     _for_igvn(NULL),
 953     _warm_calls(NULL),
 954     _orig_pc_slot(0),
 955     _orig_pc_slot_offset_in_bytes(0),
 956     _subsume_loads(true),
 957     _do_escape_analysis(false),
 958     _eliminate_boxing(false),
 959     _failure_reason(NULL),
 960     _code_buffer("Compile::Fill_buffer"),
 961     _has_method_handle_invokes(false),
 962     _mach_constant_base_node(NULL),
 963     _node_bundling_limit(0),
 964     _node_bundling_base(NULL),
 965     _java_calls(0),
 966     _inner_loops(0),
 967 #ifndef PRODUCT
 968     _trace_opto_output(TraceOptoOutput),
 969     _in_dump_cnt(0),
 970     _printer(NULL),
 971 #endif
 972     _dead_node_list(comp_arena()),
 973     _dead_node_count(0),
 974     _congraph(NULL),
 975     _replay_inline_data(NULL),
 976     _number_of_mh_late_inlines(0),
 977     _inlining_progress(false),
 978     _inlining_incrementally(false),
 979     _print_inlining_list(NULL),
 980     _print_inlining_stream(NULL),
 981     _print_inlining_idx(0),
 982     _print_inlining_output(NULL),
 983     _preserve_jvm_state(0),
 984     _allowed_reasons(0),
 985     _interpreter_frame_size(0) {
 986   C = this;
 987 
 988 #ifndef PRODUCT
 989   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 990   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
 991   set_print_assembly(PrintFrameConverterAssembly);
 992   set_parsed_irreducible_loop(false);
 993 #endif
 994   set_has_irreducible_loop(false); // no loops
 995 
 996   CompileWrapper cw(this);
 997   Init(/*AliasLevel=*/ 0);
 998   init_tf((*generator)());
 999 
1000   {
1001     // The following is a dummy for the sake of GraphKit::gen_stub
1002     Unique_Node_List for_igvn(comp_arena());
1003     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
1004     PhaseGVN gvn(Thread::current()->resource_area(),255);
1005     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
1006     gvn.transform_no_reclaim(top());
1007 
1008     GraphKit kit;
1009     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1010   }
1011 
1012   NOT_PRODUCT( verify_graph_edges(); )
1013   Code_Gen();
1014   if (failing())  return;
1015 
1016 
1017   // Entry point will be accessed using compile->stub_entry_point();
1018   if (code_buffer() == NULL) {
1019     Matcher::soft_match_failure();
1020   } else {
1021     if (PrintAssembly && (WizardMode || Verbose))
1022       tty->print_cr("### Stub::%s", stub_name);
1023 
1024     if (!failing()) {
1025       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1026 
1027       // Make the NMethod
1028       // For now we mark the frame as never safe for profile stackwalking
1029       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1030                                                       code_buffer(),
1031                                                       CodeOffsets::frame_never_safe,
1032                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1033                                                       frame_size_in_words(),
1034                                                       _oop_map_set,
1035                                                       save_arg_registers);
1036       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1037 
1038       _stub_entry_point = rs->entry_point();
1039     }
1040   }
1041 }
1042 
1043 //------------------------------Init-------------------------------------------
1044 // Prepare for a single compilation
1045 void Compile::Init(int aliaslevel) {
1046   _unique  = 0;
1047   _regalloc = NULL;
1048 
1049   _tf      = NULL;  // filled in later
1050   _top     = NULL;  // cached later
1051   _matcher = NULL;  // filled in later
1052   _cfg     = NULL;  // filled in later
1053 
1054   set_24_bit_selection_and_mode(Use24BitFP, false);
1055 
1056   _node_note_array = NULL;
1057   _default_node_notes = NULL;
1058 
1059   _immutable_memory = NULL; // filled in at first inquiry
1060 
1061   // Globally visible Nodes
1062   // First set TOP to NULL to give safe behavior during creation of RootNode
1063   set_cached_top_node(NULL);
1064   set_root(new RootNode());
1065   // Now that you have a Root to point to, create the real TOP
1066   set_cached_top_node( new ConNode(Type::TOP) );
1067   set_recent_alloc(NULL, NULL);
1068 
1069   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1070   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1071   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1072   env()->set_dependencies(new Dependencies(env()));
1073 
1074   _fixed_slots = 0;
1075   set_has_split_ifs(false);
1076   set_has_loops(has_method() && method()->has_loops()); // first approximation
1077   set_has_stringbuilder(false);
1078   set_has_boxed_value(false);
1079   _trap_can_recompile = false;  // no traps emitted yet
1080   _major_progress = true; // start out assuming good things will happen
1081   set_has_unsafe_access(false);
1082   set_max_vector_size(0);
1083   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1084   set_decompile_count(0);
1085 
1086   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1087   set_num_loop_opts(LoopOptsCount);
1088   set_do_inlining(Inline);
1089   set_max_inline_size(MaxInlineSize);
1090   set_freq_inline_size(FreqInlineSize);
1091   set_do_scheduling(OptoScheduling);
1092   set_do_count_invocations(false);
1093   set_do_method_data_update(false);
1094   set_age_code(has_method() && method()->profile_aging());
1095   set_rtm_state(NoRTM); // No RTM lock eliding by default
1096 #if INCLUDE_RTM_OPT
1097   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1098     int rtm_state = method()->method_data()->rtm_state();
1099     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1100       // Don't generate RTM lock eliding code.
1101       set_rtm_state(NoRTM);
1102     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1103       // Generate RTM lock eliding code without abort ratio calculation code.
1104       set_rtm_state(UseRTM);
1105     } else if (UseRTMDeopt) {
1106       // Generate RTM lock eliding code and include abort ratio calculation
1107       // code if UseRTMDeopt is on.
1108       set_rtm_state(ProfileRTM);
1109     }
1110   }
1111 #endif
1112   if (debug_info()->recording_non_safepoints()) {
1113     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1114                         (comp_arena(), 8, 0, NULL));
1115     set_default_node_notes(Node_Notes::make(this));
1116   }
1117 
1118   // // -- Initialize types before each compile --
1119   // // Update cached type information
1120   // if( _method && _method->constants() )
1121   //   Type::update_loaded_types(_method, _method->constants());
1122 
1123   // Init alias_type map.
1124   if (!_do_escape_analysis && aliaslevel == 3)
1125     aliaslevel = 2;  // No unique types without escape analysis
1126   _AliasLevel = aliaslevel;
1127   const int grow_ats = 16;
1128   _max_alias_types = grow_ats;
1129   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1130   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1131   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1132   {
1133     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1134   }
1135   // Initialize the first few types.
1136   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1137   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1138   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1139   _num_alias_types = AliasIdxRaw+1;
1140   // Zero out the alias type cache.
1141   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1142   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1143   probe_alias_cache(NULL)->_index = AliasIdxTop;
1144 
1145   _intrinsics = NULL;
1146   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1147   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1148   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1149   register_library_intrinsics();
1150 }
1151 
1152 //---------------------------init_start----------------------------------------
1153 // Install the StartNode on this compile object.
1154 void Compile::init_start(StartNode* s) {
1155   if (failing())
1156     return; // already failing
1157   assert(s == start(), "");
1158 }
1159 
1160 StartNode* Compile::start() const {
1161   assert(!failing(), "");
1162   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1163     Node* start = root()->fast_out(i);
1164     if( start->is_Start() )
1165       return start->as_Start();
1166   }
1167   fatal("Did not find Start node!");
1168   return NULL;
1169 }
1170 
1171 //-------------------------------immutable_memory-------------------------------------
1172 // Access immutable memory
1173 Node* Compile::immutable_memory() {
1174   if (_immutable_memory != NULL) {
1175     return _immutable_memory;
1176   }
1177   StartNode* s = start();
1178   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1179     Node *p = s->fast_out(i);
1180     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1181       _immutable_memory = p;
1182       return _immutable_memory;
1183     }
1184   }
1185   ShouldNotReachHere();
1186   return NULL;
1187 }
1188 
1189 //----------------------set_cached_top_node------------------------------------
1190 // Install the cached top node, and make sure Node::is_top works correctly.
1191 void Compile::set_cached_top_node(Node* tn) {
1192   if (tn != NULL)  verify_top(tn);
1193   Node* old_top = _top;
1194   _top = tn;
1195   // Calling Node::setup_is_top allows the nodes the chance to adjust
1196   // their _out arrays.
1197   if (_top != NULL)     _top->setup_is_top();
1198   if (old_top != NULL)  old_top->setup_is_top();
1199   assert(_top == NULL || top()->is_top(), "");
1200 }
1201 
1202 #ifdef ASSERT
1203 uint Compile::count_live_nodes_by_graph_walk() {
1204   Unique_Node_List useful(comp_arena());
1205   // Get useful node list by walking the graph.
1206   identify_useful_nodes(useful);
1207   return useful.size();
1208 }
1209 
1210 void Compile::print_missing_nodes() {
1211 
1212   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1213   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1214     return;
1215   }
1216 
1217   // This is an expensive function. It is executed only when the user
1218   // specifies VerifyIdealNodeCount option or otherwise knows the
1219   // additional work that needs to be done to identify reachable nodes
1220   // by walking the flow graph and find the missing ones using
1221   // _dead_node_list.
1222 
1223   Unique_Node_List useful(comp_arena());
1224   // Get useful node list by walking the graph.
1225   identify_useful_nodes(useful);
1226 
1227   uint l_nodes = C->live_nodes();
1228   uint l_nodes_by_walk = useful.size();
1229 
1230   if (l_nodes != l_nodes_by_walk) {
1231     if (_log != NULL) {
1232       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1233       _log->stamp();
1234       _log->end_head();
1235     }
1236     VectorSet& useful_member_set = useful.member_set();
1237     int last_idx = l_nodes_by_walk;
1238     for (int i = 0; i < last_idx; i++) {
1239       if (useful_member_set.test(i)) {
1240         if (_dead_node_list.test(i)) {
1241           if (_log != NULL) {
1242             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1243           }
1244           if (PrintIdealNodeCount) {
1245             // Print the log message to tty
1246               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1247               useful.at(i)->dump();
1248           }
1249         }
1250       }
1251       else if (! _dead_node_list.test(i)) {
1252         if (_log != NULL) {
1253           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1254         }
1255         if (PrintIdealNodeCount) {
1256           // Print the log message to tty
1257           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1258         }
1259       }
1260     }
1261     if (_log != NULL) {
1262       _log->tail("mismatched_nodes");
1263     }
1264   }
1265 }
1266 #endif
1267 
1268 #ifndef PRODUCT
1269 void Compile::verify_top(Node* tn) const {
1270   if (tn != NULL) {
1271     assert(tn->is_Con(), "top node must be a constant");
1272     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1273     assert(tn->in(0) != NULL, "must have live top node");
1274   }
1275 }
1276 #endif
1277 
1278 
1279 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1280 
1281 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1282   guarantee(arr != NULL, "");
1283   int num_blocks = arr->length();
1284   if (grow_by < num_blocks)  grow_by = num_blocks;
1285   int num_notes = grow_by * _node_notes_block_size;
1286   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1287   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1288   while (num_notes > 0) {
1289     arr->append(notes);
1290     notes     += _node_notes_block_size;
1291     num_notes -= _node_notes_block_size;
1292   }
1293   assert(num_notes == 0, "exact multiple, please");
1294 }
1295 
1296 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1297   if (source == NULL || dest == NULL)  return false;
1298 
1299   if (dest->is_Con())
1300     return false;               // Do not push debug info onto constants.
1301 
1302 #ifdef ASSERT
1303   // Leave a bread crumb trail pointing to the original node:
1304   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1305     dest->set_debug_orig(source);
1306   }
1307 #endif
1308 
1309   if (node_note_array() == NULL)
1310     return false;               // Not collecting any notes now.
1311 
1312   // This is a copy onto a pre-existing node, which may already have notes.
1313   // If both nodes have notes, do not overwrite any pre-existing notes.
1314   Node_Notes* source_notes = node_notes_at(source->_idx);
1315   if (source_notes == NULL || source_notes->is_clear())  return false;
1316   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1317   if (dest_notes == NULL || dest_notes->is_clear()) {
1318     return set_node_notes_at(dest->_idx, source_notes);
1319   }
1320 
1321   Node_Notes merged_notes = (*source_notes);
1322   // The order of operations here ensures that dest notes will win...
1323   merged_notes.update_from(dest_notes);
1324   return set_node_notes_at(dest->_idx, &merged_notes);
1325 }
1326 
1327 
1328 //--------------------------allow_range_check_smearing-------------------------
1329 // Gating condition for coalescing similar range checks.
1330 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1331 // single covering check that is at least as strong as any of them.
1332 // If the optimization succeeds, the simplified (strengthened) range check
1333 // will always succeed.  If it fails, we will deopt, and then give up
1334 // on the optimization.
1335 bool Compile::allow_range_check_smearing() const {
1336   // If this method has already thrown a range-check,
1337   // assume it was because we already tried range smearing
1338   // and it failed.
1339   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1340   return !already_trapped;
1341 }
1342 
1343 
1344 //------------------------------flatten_alias_type-----------------------------
1345 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1346   int offset = tj->offset();
1347   TypePtr::PTR ptr = tj->ptr();
1348 
1349   // Known instance (scalarizable allocation) alias only with itself.
1350   bool is_known_inst = tj->isa_oopptr() != NULL &&
1351                        tj->is_oopptr()->is_known_instance();
1352 
1353   // Process weird unsafe references.
1354   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1355     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1356     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1357     tj = TypeOopPtr::BOTTOM;
1358     ptr = tj->ptr();
1359     offset = tj->offset();
1360   }
1361 
1362   // Array pointers need some flattening
1363   const TypeAryPtr *ta = tj->isa_aryptr();
1364   if (ta && ta->is_stable()) {
1365     // Erase stability property for alias analysis.
1366     tj = ta = ta->cast_to_stable(false);
1367   }
1368   if( ta && is_known_inst ) {
1369     if ( offset != Type::OffsetBot &&
1370          offset > arrayOopDesc::length_offset_in_bytes() ) {
1371       offset = Type::OffsetBot; // Flatten constant access into array body only
1372       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1373     }
1374   } else if( ta && _AliasLevel >= 2 ) {
1375     // For arrays indexed by constant indices, we flatten the alias
1376     // space to include all of the array body.  Only the header, klass
1377     // and array length can be accessed un-aliased.
1378     if( offset != Type::OffsetBot ) {
1379       if( ta->const_oop() ) { // MethodData* or Method*
1380         offset = Type::OffsetBot;   // Flatten constant access into array body
1381         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1382       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1383         // range is OK as-is.
1384         tj = ta = TypeAryPtr::RANGE;
1385       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1386         tj = TypeInstPtr::KLASS; // all klass loads look alike
1387         ta = TypeAryPtr::RANGE; // generic ignored junk
1388         ptr = TypePtr::BotPTR;
1389       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1390         tj = TypeInstPtr::MARK;
1391         ta = TypeAryPtr::RANGE; // generic ignored junk
1392         ptr = TypePtr::BotPTR;
1393       } else {                  // Random constant offset into array body
1394         offset = Type::OffsetBot;   // Flatten constant access into array body
1395         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1396       }
1397     }
1398     // Arrays of fixed size alias with arrays of unknown size.
1399     if (ta->size() != TypeInt::POS) {
1400       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1401       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1402     }
1403     // Arrays of known objects become arrays of unknown objects.
1404     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1405       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1406       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1407     }
1408     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1409       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1410       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1411     }
1412     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1413     // cannot be distinguished by bytecode alone.
1414     if (ta->elem() == TypeInt::BOOL) {
1415       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1416       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1417       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1418     }
1419     // During the 2nd round of IterGVN, NotNull castings are removed.
1420     // Make sure the Bottom and NotNull variants alias the same.
1421     // Also, make sure exact and non-exact variants alias the same.
1422     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1423       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1424     }
1425   }
1426 
1427   // Oop pointers need some flattening
1428   const TypeInstPtr *to = tj->isa_instptr();
1429   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1430     ciInstanceKlass *k = to->klass()->as_instance_klass();
1431     if( ptr == TypePtr::Constant ) {
1432       if (to->klass() != ciEnv::current()->Class_klass() ||
1433           offset < k->size_helper() * wordSize) {
1434         // No constant oop pointers (such as Strings); they alias with
1435         // unknown strings.
1436         assert(!is_known_inst, "not scalarizable allocation");
1437         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1438       }
1439     } else if( is_known_inst ) {
1440       tj = to; // Keep NotNull and klass_is_exact for instance type
1441     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1442       // During the 2nd round of IterGVN, NotNull castings are removed.
1443       // Make sure the Bottom and NotNull variants alias the same.
1444       // Also, make sure exact and non-exact variants alias the same.
1445       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1446     }
1447     if (to->speculative() != NULL) {
1448       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1449     }
1450     // Canonicalize the holder of this field
1451     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1452       // First handle header references such as a LoadKlassNode, even if the
1453       // object's klass is unloaded at compile time (4965979).
1454       if (!is_known_inst) { // Do it only for non-instance types
1455         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1456       }
1457     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1458       // Static fields are in the space above the normal instance
1459       // fields in the java.lang.Class instance.
1460       if (to->klass() != ciEnv::current()->Class_klass()) {
1461         to = NULL;
1462         tj = TypeOopPtr::BOTTOM;
1463         offset = tj->offset();
1464       }
1465     } else {
1466       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1467       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1468         if( is_known_inst ) {
1469           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1470         } else {
1471           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1472         }
1473       }
1474     }
1475   }
1476 
1477   // Klass pointers to object array klasses need some flattening
1478   const TypeKlassPtr *tk = tj->isa_klassptr();
1479   if( tk ) {
1480     // If we are referencing a field within a Klass, we need
1481     // to assume the worst case of an Object.  Both exact and
1482     // inexact types must flatten to the same alias class so
1483     // use NotNull as the PTR.
1484     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1485 
1486       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1487                                    TypeKlassPtr::OBJECT->klass(),
1488                                    offset);
1489     }
1490 
1491     ciKlass* klass = tk->klass();
1492     if( klass->is_obj_array_klass() ) {
1493       ciKlass* k = TypeAryPtr::OOPS->klass();
1494       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1495         k = TypeInstPtr::BOTTOM->klass();
1496       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1497     }
1498 
1499     // Check for precise loads from the primary supertype array and force them
1500     // to the supertype cache alias index.  Check for generic array loads from
1501     // the primary supertype array and also force them to the supertype cache
1502     // alias index.  Since the same load can reach both, we need to merge
1503     // these 2 disparate memories into the same alias class.  Since the
1504     // primary supertype array is read-only, there's no chance of confusion
1505     // where we bypass an array load and an array store.
1506     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1507     if (offset == Type::OffsetBot ||
1508         (offset >= primary_supers_offset &&
1509          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1510         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1511       offset = in_bytes(Klass::secondary_super_cache_offset());
1512       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1513     }
1514   }
1515 
1516   // Flatten all Raw pointers together.
1517   if (tj->base() == Type::RawPtr)
1518     tj = TypeRawPtr::BOTTOM;
1519 
1520   if (tj->base() == Type::AnyPtr)
1521     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1522 
1523   // Flatten all to bottom for now
1524   switch( _AliasLevel ) {
1525   case 0:
1526     tj = TypePtr::BOTTOM;
1527     break;
1528   case 1:                       // Flatten to: oop, static, field or array
1529     switch (tj->base()) {
1530     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1531     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1532     case Type::AryPtr:   // do not distinguish arrays at all
1533     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1534     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1535     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1536     default: ShouldNotReachHere();
1537     }
1538     break;
1539   case 2:                       // No collapsing at level 2; keep all splits
1540   case 3:                       // No collapsing at level 3; keep all splits
1541     break;
1542   default:
1543     Unimplemented();
1544   }
1545 
1546   offset = tj->offset();
1547   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1548 
1549   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1550           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1551           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1552           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1553           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1554           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1555           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1556           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1557   assert( tj->ptr() != TypePtr::TopPTR &&
1558           tj->ptr() != TypePtr::AnyNull &&
1559           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1560 //    assert( tj->ptr() != TypePtr::Constant ||
1561 //            tj->base() == Type::RawPtr ||
1562 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1563 
1564   return tj;
1565 }
1566 
1567 void Compile::AliasType::Init(int i, const TypePtr* at) {
1568   _index = i;
1569   _adr_type = at;
1570   _field = NULL;
1571   _element = NULL;
1572   _is_rewritable = true; // default
1573   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1574   if (atoop != NULL && atoop->is_known_instance()) {
1575     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1576     _general_index = Compile::current()->get_alias_index(gt);
1577   } else {
1578     _general_index = 0;
1579   }
1580 }
1581 
1582 //---------------------------------print_on------------------------------------
1583 #ifndef PRODUCT
1584 void Compile::AliasType::print_on(outputStream* st) {
1585   if (index() < 10)
1586         st->print("@ <%d> ", index());
1587   else  st->print("@ <%d>",  index());
1588   st->print(is_rewritable() ? "   " : " RO");
1589   int offset = adr_type()->offset();
1590   if (offset == Type::OffsetBot)
1591         st->print(" +any");
1592   else  st->print(" +%-3d", offset);
1593   st->print(" in ");
1594   adr_type()->dump_on(st);
1595   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1596   if (field() != NULL && tjp) {
1597     if (tjp->klass()  != field()->holder() ||
1598         tjp->offset() != field()->offset_in_bytes()) {
1599       st->print(" != ");
1600       field()->print();
1601       st->print(" ***");
1602     }
1603   }
1604 }
1605 
1606 void print_alias_types() {
1607   Compile* C = Compile::current();
1608   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1609   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1610     C->alias_type(idx)->print_on(tty);
1611     tty->cr();
1612   }
1613 }
1614 #endif
1615 
1616 
1617 //----------------------------probe_alias_cache--------------------------------
1618 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1619   intptr_t key = (intptr_t) adr_type;
1620   key ^= key >> logAliasCacheSize;
1621   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1622 }
1623 
1624 
1625 //-----------------------------grow_alias_types--------------------------------
1626 void Compile::grow_alias_types() {
1627   const int old_ats  = _max_alias_types; // how many before?
1628   const int new_ats  = old_ats;          // how many more?
1629   const int grow_ats = old_ats+new_ats;  // how many now?
1630   _max_alias_types = grow_ats;
1631   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1632   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1633   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1634   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1635 }
1636 
1637 
1638 //--------------------------------find_alias_type------------------------------
1639 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1640   if (_AliasLevel == 0)
1641     return alias_type(AliasIdxBot);
1642 
1643   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1644   if (ace->_adr_type == adr_type) {
1645     return alias_type(ace->_index);
1646   }
1647 
1648   // Handle special cases.
1649   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1650   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1651 
1652   // Do it the slow way.
1653   const TypePtr* flat = flatten_alias_type(adr_type);
1654 
1655 #ifdef ASSERT
1656   assert(flat == flatten_alias_type(flat), "idempotent");
1657   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1658   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1659     const TypeOopPtr* foop = flat->is_oopptr();
1660     // Scalarizable allocations have exact klass always.
1661     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1662     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1663     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1664   }
1665   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1666 #endif
1667 
1668   int idx = AliasIdxTop;
1669   for (int i = 0; i < num_alias_types(); i++) {
1670     if (alias_type(i)->adr_type() == flat) {
1671       idx = i;
1672       break;
1673     }
1674   }
1675 
1676   if (idx == AliasIdxTop) {
1677     if (no_create)  return NULL;
1678     // Grow the array if necessary.
1679     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1680     // Add a new alias type.
1681     idx = _num_alias_types++;
1682     _alias_types[idx]->Init(idx, flat);
1683     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1684     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1685     if (flat->isa_instptr()) {
1686       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1687           && flat->is_instptr()->klass() == env()->Class_klass())
1688         alias_type(idx)->set_rewritable(false);
1689     }
1690     if (flat->isa_aryptr()) {
1691 #ifdef ASSERT
1692       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1693       // (T_BYTE has the weakest alignment and size restrictions...)
1694       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1695 #endif
1696       if (flat->offset() == TypePtr::OffsetBot) {
1697         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1698       }
1699     }
1700     if (flat->isa_klassptr()) {
1701       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1702         alias_type(idx)->set_rewritable(false);
1703       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1704         alias_type(idx)->set_rewritable(false);
1705       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1706         alias_type(idx)->set_rewritable(false);
1707       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1708         alias_type(idx)->set_rewritable(false);
1709     }
1710     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1711     // but the base pointer type is not distinctive enough to identify
1712     // references into JavaThread.)
1713 
1714     // Check for final fields.
1715     const TypeInstPtr* tinst = flat->isa_instptr();
1716     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1717       ciField* field;
1718       if (tinst->const_oop() != NULL &&
1719           tinst->klass() == ciEnv::current()->Class_klass() &&
1720           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1721         // static field
1722         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1723         field = k->get_field_by_offset(tinst->offset(), true);
1724       } else {
1725         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1726         field = k->get_field_by_offset(tinst->offset(), false);
1727       }
1728       assert(field == NULL ||
1729              original_field == NULL ||
1730              (field->holder() == original_field->holder() &&
1731               field->offset() == original_field->offset() &&
1732               field->is_static() == original_field->is_static()), "wrong field?");
1733       // Set field() and is_rewritable() attributes.
1734       if (field != NULL)  alias_type(idx)->set_field(field);
1735     }
1736   }
1737 
1738   // Fill the cache for next time.
1739   ace->_adr_type = adr_type;
1740   ace->_index    = idx;
1741   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1742 
1743   // Might as well try to fill the cache for the flattened version, too.
1744   AliasCacheEntry* face = probe_alias_cache(flat);
1745   if (face->_adr_type == NULL) {
1746     face->_adr_type = flat;
1747     face->_index    = idx;
1748     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1749   }
1750 
1751   return alias_type(idx);
1752 }
1753 
1754 
1755 Compile::AliasType* Compile::alias_type(ciField* field) {
1756   const TypeOopPtr* t;
1757   if (field->is_static())
1758     t = TypeInstPtr::make(field->holder()->java_mirror());
1759   else
1760     t = TypeOopPtr::make_from_klass_raw(field->holder());
1761   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1762   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1763   return atp;
1764 }
1765 
1766 
1767 //------------------------------have_alias_type--------------------------------
1768 bool Compile::have_alias_type(const TypePtr* adr_type) {
1769   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1770   if (ace->_adr_type == adr_type) {
1771     return true;
1772   }
1773 
1774   // Handle special cases.
1775   if (adr_type == NULL)             return true;
1776   if (adr_type == TypePtr::BOTTOM)  return true;
1777 
1778   return find_alias_type(adr_type, true, NULL) != NULL;
1779 }
1780 
1781 //-----------------------------must_alias--------------------------------------
1782 // True if all values of the given address type are in the given alias category.
1783 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1784   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1785   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1786   if (alias_idx == AliasIdxTop)         return false; // the empty category
1787   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1788 
1789   // the only remaining possible overlap is identity
1790   int adr_idx = get_alias_index(adr_type);
1791   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1792   assert(adr_idx == alias_idx ||
1793          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1794           && adr_type                       != TypeOopPtr::BOTTOM),
1795          "should not be testing for overlap with an unsafe pointer");
1796   return adr_idx == alias_idx;
1797 }
1798 
1799 //------------------------------can_alias--------------------------------------
1800 // True if any values of the given address type are in the given alias category.
1801 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1802   if (alias_idx == AliasIdxTop)         return false; // the empty category
1803   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1804   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1805   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1806 
1807   // the only remaining possible overlap is identity
1808   int adr_idx = get_alias_index(adr_type);
1809   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1810   return adr_idx == alias_idx;
1811 }
1812 
1813 
1814 
1815 //---------------------------pop_warm_call-------------------------------------
1816 WarmCallInfo* Compile::pop_warm_call() {
1817   WarmCallInfo* wci = _warm_calls;
1818   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1819   return wci;
1820 }
1821 
1822 //----------------------------Inline_Warm--------------------------------------
1823 int Compile::Inline_Warm() {
1824   // If there is room, try to inline some more warm call sites.
1825   // %%% Do a graph index compaction pass when we think we're out of space?
1826   if (!InlineWarmCalls)  return 0;
1827 
1828   int calls_made_hot = 0;
1829   int room_to_grow   = NodeCountInliningCutoff - unique();
1830   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1831   int amount_grown   = 0;
1832   WarmCallInfo* call;
1833   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1834     int est_size = (int)call->size();
1835     if (est_size > (room_to_grow - amount_grown)) {
1836       // This one won't fit anyway.  Get rid of it.
1837       call->make_cold();
1838       continue;
1839     }
1840     call->make_hot();
1841     calls_made_hot++;
1842     amount_grown   += est_size;
1843     amount_to_grow -= est_size;
1844   }
1845 
1846   if (calls_made_hot > 0)  set_major_progress();
1847   return calls_made_hot;
1848 }
1849 
1850 
1851 //----------------------------Finish_Warm--------------------------------------
1852 void Compile::Finish_Warm() {
1853   if (!InlineWarmCalls)  return;
1854   if (failing())  return;
1855   if (warm_calls() == NULL)  return;
1856 
1857   // Clean up loose ends, if we are out of space for inlining.
1858   WarmCallInfo* call;
1859   while ((call = pop_warm_call()) != NULL) {
1860     call->make_cold();
1861   }
1862 }
1863 
1864 //---------------------cleanup_loop_predicates-----------------------
1865 // Remove the opaque nodes that protect the predicates so that all unused
1866 // checks and uncommon_traps will be eliminated from the ideal graph
1867 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1868   if (predicate_count()==0) return;
1869   for (int i = predicate_count(); i > 0; i--) {
1870     Node * n = predicate_opaque1_node(i-1);
1871     assert(n->Opcode() == Op_Opaque1, "must be");
1872     igvn.replace_node(n, n->in(1));
1873   }
1874   assert(predicate_count()==0, "should be clean!");
1875 }
1876 
1877 // StringOpts and late inlining of string methods
1878 void Compile::inline_string_calls(bool parse_time) {
1879   {
1880     // remove useless nodes to make the usage analysis simpler
1881     ResourceMark rm;
1882     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1883   }
1884 
1885   {
1886     ResourceMark rm;
1887     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1888     PhaseStringOpts pso(initial_gvn(), for_igvn());
1889     print_method(PHASE_AFTER_STRINGOPTS, 3);
1890   }
1891 
1892   // now inline anything that we skipped the first time around
1893   if (!parse_time) {
1894     _late_inlines_pos = _late_inlines.length();
1895   }
1896 
1897   while (_string_late_inlines.length() > 0) {
1898     CallGenerator* cg = _string_late_inlines.pop();
1899     cg->do_late_inline();
1900     if (failing())  return;
1901   }
1902   _string_late_inlines.trunc_to(0);
1903 }
1904 
1905 // Late inlining of boxing methods
1906 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1907   if (_boxing_late_inlines.length() > 0) {
1908     assert(has_boxed_value(), "inconsistent");
1909 
1910     PhaseGVN* gvn = initial_gvn();
1911     set_inlining_incrementally(true);
1912 
1913     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1914     for_igvn()->clear();
1915     gvn->replace_with(&igvn);
1916 
1917     while (_boxing_late_inlines.length() > 0) {
1918       CallGenerator* cg = _boxing_late_inlines.pop();
1919       cg->do_late_inline();
1920       if (failing())  return;
1921     }
1922     _boxing_late_inlines.trunc_to(0);
1923 
1924     {
1925       ResourceMark rm;
1926       PhaseRemoveUseless pru(gvn, for_igvn());
1927     }
1928 
1929     igvn = PhaseIterGVN(gvn);
1930     igvn.optimize();
1931 
1932     set_inlining_progress(false);
1933     set_inlining_incrementally(false);
1934   }
1935 }
1936 
1937 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1938   assert(IncrementalInline, "incremental inlining should be on");
1939   PhaseGVN* gvn = initial_gvn();
1940 
1941   set_inlining_progress(false);
1942   for_igvn()->clear();
1943   gvn->replace_with(&igvn);
1944 
1945   int i = 0;
1946 
1947   for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1948     CallGenerator* cg = _late_inlines.at(i);
1949     _late_inlines_pos = i+1;
1950     cg->do_late_inline();
1951     if (failing())  return;
1952   }
1953   int j = 0;
1954   for (; i < _late_inlines.length(); i++, j++) {
1955     _late_inlines.at_put(j, _late_inlines.at(i));
1956   }
1957   _late_inlines.trunc_to(j);
1958 
1959   {
1960     ResourceMark rm;
1961     PhaseRemoveUseless pru(gvn, for_igvn());
1962   }
1963 
1964   igvn = PhaseIterGVN(gvn);
1965 }
1966 
1967 // Perform incremental inlining until bound on number of live nodes is reached
1968 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1969   PhaseGVN* gvn = initial_gvn();
1970 
1971   set_inlining_incrementally(true);
1972   set_inlining_progress(true);
1973   uint low_live_nodes = 0;
1974 
1975   while(inlining_progress() && _late_inlines.length() > 0) {
1976 
1977     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1978       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
1979         // PhaseIdealLoop is expensive so we only try it once we are
1980         // out of loop and we only try it again if the previous helped
1981         // got the number of nodes down significantly
1982         PhaseIdealLoop ideal_loop( igvn, false, true );
1983         if (failing())  return;
1984         low_live_nodes = live_nodes();
1985         _major_progress = true;
1986       }
1987 
1988       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1989         break;
1990       }
1991     }
1992 
1993     inline_incrementally_one(igvn);
1994 
1995     if (failing())  return;
1996 
1997     igvn.optimize();
1998 
1999     if (failing())  return;
2000   }
2001 
2002   assert( igvn._worklist.size() == 0, "should be done with igvn" );
2003 
2004   if (_string_late_inlines.length() > 0) {
2005     assert(has_stringbuilder(), "inconsistent");
2006     for_igvn()->clear();
2007     initial_gvn()->replace_with(&igvn);
2008 
2009     inline_string_calls(false);
2010 
2011     if (failing())  return;
2012 
2013     {
2014       ResourceMark rm;
2015       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2016     }
2017 
2018     igvn = PhaseIterGVN(gvn);
2019 
2020     igvn.optimize();
2021   }
2022 
2023   set_inlining_incrementally(false);
2024 }
2025 
2026 
2027 //------------------------------Optimize---------------------------------------
2028 // Given a graph, optimize it.
2029 void Compile::Optimize() {
2030   TracePhase t1("optimizer", &_t_optimizer, true);
2031 
2032 #ifndef PRODUCT
2033   if (env()->break_at_compile()) {
2034     BREAKPOINT;
2035   }
2036 
2037 #endif
2038 
2039   ResourceMark rm;
2040   int          loop_opts_cnt;
2041 
2042   print_inlining_reinit();
2043 
2044   NOT_PRODUCT( verify_graph_edges(); )
2045 
2046   print_method(PHASE_AFTER_PARSING);
2047 
2048  {
2049   // Iterative Global Value Numbering, including ideal transforms
2050   // Initialize IterGVN with types and values from parse-time GVN
2051   PhaseIterGVN igvn(initial_gvn());
2052   {
2053     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2054     igvn.optimize();
2055   }
2056 
2057   print_method(PHASE_ITER_GVN1, 2);
2058 
2059   if (failing())  return;
2060 
2061   {
2062     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2063     inline_incrementally(igvn);
2064   }
2065 
2066   print_method(PHASE_INCREMENTAL_INLINE, 2);
2067 
2068   if (failing())  return;
2069 
2070   if (eliminate_boxing()) {
2071     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2072     // Inline valueOf() methods now.
2073     inline_boxing_calls(igvn);
2074 
2075     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2076 
2077     if (failing())  return;
2078   }
2079 
2080   // Remove the speculative part of types and clean up the graph from
2081   // the extra CastPP nodes whose only purpose is to carry them. Do
2082   // that early so that optimizations are not disrupted by the extra
2083   // CastPP nodes.
2084   remove_speculative_types(igvn);
2085 
2086   // No more new expensive nodes will be added to the list from here
2087   // so keep only the actual candidates for optimizations.
2088   cleanup_expensive_nodes(igvn);
2089 
2090   // Perform escape analysis
2091   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2092     if (has_loops()) {
2093       // Cleanup graph (remove dead nodes).
2094       TracePhase t2("idealLoop", &_t_idealLoop, true);
2095       PhaseIdealLoop ideal_loop( igvn, false, true );
2096       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2097       if (failing())  return;
2098     }
2099     ConnectionGraph::do_analysis(this, &igvn);
2100 
2101     if (failing())  return;
2102 
2103     // Optimize out fields loads from scalar replaceable allocations.
2104     igvn.optimize();
2105     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2106 
2107     if (failing())  return;
2108 
2109     if (congraph() != NULL && macro_count() > 0) {
2110       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2111       PhaseMacroExpand mexp(igvn);
2112       mexp.eliminate_macro_nodes();
2113       igvn.set_delay_transform(false);
2114 
2115       igvn.optimize();
2116       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2117 
2118       if (failing())  return;
2119     }
2120   }
2121 
2122   // Loop transforms on the ideal graph.  Range Check Elimination,
2123   // peeling, unrolling, etc.
2124 
2125   // Set loop opts counter
2126   loop_opts_cnt = num_loop_opts();
2127   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2128     {
2129       TracePhase t2("idealLoop", &_t_idealLoop, true);
2130       PhaseIdealLoop ideal_loop( igvn, true );
2131       loop_opts_cnt--;
2132       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2133       if (failing())  return;
2134     }
2135     // Loop opts pass if partial peeling occurred in previous pass
2136     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2137       TracePhase t3("idealLoop", &_t_idealLoop, true);
2138       PhaseIdealLoop ideal_loop( igvn, false );
2139       loop_opts_cnt--;
2140       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2141       if (failing())  return;
2142     }
2143     // Loop opts pass for loop-unrolling before CCP
2144     if(major_progress() && (loop_opts_cnt > 0)) {
2145       TracePhase t4("idealLoop", &_t_idealLoop, true);
2146       PhaseIdealLoop ideal_loop( igvn, false );
2147       loop_opts_cnt--;
2148       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2149     }
2150     if (!failing()) {
2151       // Verify that last round of loop opts produced a valid graph
2152       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2153       PhaseIdealLoop::verify(igvn);
2154     }
2155   }
2156   if (failing())  return;
2157 
2158   // Conditional Constant Propagation;
2159   PhaseCCP ccp( &igvn );
2160   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2161   {
2162     TracePhase t2("ccp", &_t_ccp, true);
2163     ccp.do_transform();
2164   }
2165   print_method(PHASE_CPP1, 2);
2166 
2167   assert( true, "Break here to ccp.dump_old2new_map()");
2168 
2169   // Iterative Global Value Numbering, including ideal transforms
2170   {
2171     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2172     igvn = ccp;
2173     igvn.optimize();
2174   }
2175 
2176   print_method(PHASE_ITER_GVN2, 2);
2177 
2178   if (failing())  return;
2179 
2180   // Loop transforms on the ideal graph.  Range Check Elimination,
2181   // peeling, unrolling, etc.
2182   if(loop_opts_cnt > 0) {
2183     debug_only( int cnt = 0; );
2184     while(major_progress() && (loop_opts_cnt > 0)) {
2185       TracePhase t2("idealLoop", &_t_idealLoop, true);
2186       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2187       PhaseIdealLoop ideal_loop( igvn, true);
2188       loop_opts_cnt--;
2189       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2190       if (failing())  return;
2191     }
2192   }
2193 
2194   {
2195     // Verify that all previous optimizations produced a valid graph
2196     // at least to this point, even if no loop optimizations were done.
2197     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2198     PhaseIdealLoop::verify(igvn);
2199   }
2200 
2201   {
2202     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2203     PhaseMacroExpand  mex(igvn);
2204     if (mex.expand_macro_nodes()) {
2205       assert(failing(), "must bail out w/ explicit message");
2206       return;
2207     }
2208   }
2209 
2210  } // (End scope of igvn; run destructor if necessary for asserts.)
2211 
2212   process_print_inlining();
2213   // A method with only infinite loops has no edges entering loops from root
2214   {
2215     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2216     if (final_graph_reshaping()) {
2217       assert(failing(), "must bail out w/ explicit message");
2218       return;
2219     }
2220   }
2221 
2222   print_method(PHASE_OPTIMIZE_FINISHED, 2);
2223 }
2224 
2225 
2226 //------------------------------Code_Gen---------------------------------------
2227 // Given a graph, generate code for it
2228 void Compile::Code_Gen() {
2229   if (failing()) {
2230     return;
2231   }
2232 
2233   // Perform instruction selection.  You might think we could reclaim Matcher
2234   // memory PDQ, but actually the Matcher is used in generating spill code.
2235   // Internals of the Matcher (including some VectorSets) must remain live
2236   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2237   // set a bit in reclaimed memory.
2238 
2239   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2240   // nodes.  Mapping is only valid at the root of each matched subtree.
2241   NOT_PRODUCT( verify_graph_edges(); )
2242 
2243   Matcher matcher;
2244   _matcher = &matcher;
2245   {
2246     TracePhase t2("matcher", &_t_matcher, true);
2247     matcher.match();
2248   }
2249   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2250   // nodes.  Mapping is only valid at the root of each matched subtree.
2251   NOT_PRODUCT( verify_graph_edges(); )
2252 
2253   // If you have too many nodes, or if matching has failed, bail out
2254   check_node_count(0, "out of nodes matching instructions");
2255   if (failing()) {
2256     return;
2257   }
2258 
2259   // Build a proper-looking CFG
2260   PhaseCFG cfg(node_arena(), root(), matcher);
2261   _cfg = &cfg;
2262   {
2263     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2264     bool success = cfg.do_global_code_motion();
2265     if (!success) {
2266       return;
2267     }
2268 
2269     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2270     NOT_PRODUCT( verify_graph_edges(); )
2271     debug_only( cfg.verify(); )
2272   }
2273 
2274   PhaseChaitin regalloc(unique(), cfg, matcher);
2275   _regalloc = &regalloc;
2276   {
2277     TracePhase t2("regalloc", &_t_registerAllocation, true);
2278     // Perform register allocation.  After Chaitin, use-def chains are
2279     // no longer accurate (at spill code) and so must be ignored.
2280     // Node->LRG->reg mappings are still accurate.
2281     _regalloc->Register_Allocate();
2282 
2283     // Bail out if the allocator builds too many nodes
2284     if (failing()) {
2285       return;
2286     }
2287   }
2288 
2289   // Prior to register allocation we kept empty basic blocks in case the
2290   // the allocator needed a place to spill.  After register allocation we
2291   // are not adding any new instructions.  If any basic block is empty, we
2292   // can now safely remove it.
2293   {
2294     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2295     cfg.remove_empty_blocks();
2296     if (do_freq_based_layout()) {
2297       PhaseBlockLayout layout(cfg);
2298     } else {
2299       cfg.set_loop_alignment();
2300     }
2301     cfg.fixup_flow();
2302   }
2303 
2304   // Apply peephole optimizations
2305   if( OptoPeephole ) {
2306     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2307     PhasePeephole peep( _regalloc, cfg);
2308     peep.do_transform();
2309   }
2310 
2311   // Do late expand if CPU requires this.
2312   if (Matcher::require_postalloc_expand) {
2313     NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));
2314     cfg.postalloc_expand(_regalloc);
2315   }
2316 
2317   // Convert Nodes to instruction bits in a buffer
2318   {
2319     // %%%% workspace merge brought two timers together for one job
2320     TracePhase t2a("output", &_t_output, true);
2321     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2322     Output();
2323   }
2324 
2325   print_method(PHASE_FINAL_CODE);
2326 
2327   // He's dead, Jim.
2328   _cfg     = (PhaseCFG*)0xdeadbeef;
2329   _regalloc = (PhaseChaitin*)0xdeadbeef;
2330 }
2331 
2332 
2333 //------------------------------dump_asm---------------------------------------
2334 // Dump formatted assembly
2335 #ifndef PRODUCT
2336 void Compile::dump_asm(int *pcs, uint pc_limit) {
2337   bool cut_short = false;
2338   tty->print_cr("#");
2339   tty->print("#  ");  _tf->dump();  tty->cr();
2340   tty->print_cr("#");
2341 
2342   // For all blocks
2343   int pc = 0x0;                 // Program counter
2344   char starts_bundle = ' ';
2345   _regalloc->dump_frame();
2346 
2347   Node *n = NULL;
2348   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2349     if (VMThread::should_terminate()) {
2350       cut_short = true;
2351       break;
2352     }
2353     Block* block = _cfg->get_block(i);
2354     if (block->is_connector() && !Verbose) {
2355       continue;
2356     }
2357     n = block->head();
2358     if (pcs && n->_idx < pc_limit) {
2359       tty->print("%3.3x   ", pcs[n->_idx]);
2360     } else {
2361       tty->print("      ");
2362     }
2363     block->dump_head(_cfg);
2364     if (block->is_connector()) {
2365       tty->print_cr("        # Empty connector block");
2366     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2367       tty->print_cr("        # Block is sole successor of call");
2368     }
2369 
2370     // For all instructions
2371     Node *delay = NULL;
2372     for (uint j = 0; j < block->number_of_nodes(); j++) {
2373       if (VMThread::should_terminate()) {
2374         cut_short = true;
2375         break;
2376       }
2377       n = block->get_node(j);
2378       if (valid_bundle_info(n)) {
2379         Bundle* bundle = node_bundling(n);
2380         if (bundle->used_in_unconditional_delay()) {
2381           delay = n;
2382           continue;
2383         }
2384         if (bundle->starts_bundle()) {
2385           starts_bundle = '+';
2386         }
2387       }
2388 
2389       if (WizardMode) {
2390         n->dump();
2391       }
2392 
2393       if( !n->is_Region() &&    // Dont print in the Assembly
2394           !n->is_Phi() &&       // a few noisely useless nodes
2395           !n->is_Proj() &&
2396           !n->is_MachTemp() &&
2397           !n->is_SafePointScalarObject() &&
2398           !n->is_Catch() &&     // Would be nice to print exception table targets
2399           !n->is_MergeMem() &&  // Not very interesting
2400           !n->is_top() &&       // Debug info table constants
2401           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2402           ) {
2403         if (pcs && n->_idx < pc_limit)
2404           tty->print("%3.3x", pcs[n->_idx]);
2405         else
2406           tty->print("   ");
2407         tty->print(" %c ", starts_bundle);
2408         starts_bundle = ' ';
2409         tty->print("\t");
2410         n->format(_regalloc, tty);
2411         tty->cr();
2412       }
2413 
2414       // If we have an instruction with a delay slot, and have seen a delay,
2415       // then back up and print it
2416       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2417         assert(delay != NULL, "no unconditional delay instruction");
2418         if (WizardMode) delay->dump();
2419 
2420         if (node_bundling(delay)->starts_bundle())
2421           starts_bundle = '+';
2422         if (pcs && n->_idx < pc_limit)
2423           tty->print("%3.3x", pcs[n->_idx]);
2424         else
2425           tty->print("   ");
2426         tty->print(" %c ", starts_bundle);
2427         starts_bundle = ' ';
2428         tty->print("\t");
2429         delay->format(_regalloc, tty);
2430         tty->cr();
2431         delay = NULL;
2432       }
2433 
2434       // Dump the exception table as well
2435       if( n->is_Catch() && (Verbose || WizardMode) ) {
2436         // Print the exception table for this offset
2437         _handler_table.print_subtable_for(pc);
2438       }
2439     }
2440 
2441     if (pcs && n->_idx < pc_limit)
2442       tty->print_cr("%3.3x", pcs[n->_idx]);
2443     else
2444       tty->cr();
2445 
2446     assert(cut_short || delay == NULL, "no unconditional delay branch");
2447 
2448   } // End of per-block dump
2449   tty->cr();
2450 
2451   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2452 }
2453 #endif
2454 
2455 //------------------------------Final_Reshape_Counts---------------------------
2456 // This class defines counters to help identify when a method
2457 // may/must be executed using hardware with only 24-bit precision.
2458 struct Final_Reshape_Counts : public StackObj {
2459   int  _call_count;             // count non-inlined 'common' calls
2460   int  _float_count;            // count float ops requiring 24-bit precision
2461   int  _double_count;           // count double ops requiring more precision
2462   int  _java_call_count;        // count non-inlined 'java' calls
2463   int  _inner_loop_count;       // count loops which need alignment
2464   VectorSet _visited;           // Visitation flags
2465   Node_List _tests;             // Set of IfNodes & PCTableNodes
2466 
2467   Final_Reshape_Counts() :
2468     _call_count(0), _float_count(0), _double_count(0),
2469     _java_call_count(0), _inner_loop_count(0),
2470     _visited( Thread::current()->resource_area() ) { }
2471 
2472   void inc_call_count  () { _call_count  ++; }
2473   void inc_float_count () { _float_count ++; }
2474   void inc_double_count() { _double_count++; }
2475   void inc_java_call_count() { _java_call_count++; }
2476   void inc_inner_loop_count() { _inner_loop_count++; }
2477 
2478   int  get_call_count  () const { return _call_count  ; }
2479   int  get_float_count () const { return _float_count ; }
2480   int  get_double_count() const { return _double_count; }
2481   int  get_java_call_count() const { return _java_call_count; }
2482   int  get_inner_loop_count() const { return _inner_loop_count; }
2483 };
2484 
2485 #ifdef ASSERT
2486 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2487   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2488   // Make sure the offset goes inside the instance layout.
2489   return k->contains_field_offset(tp->offset());
2490   // Note that OffsetBot and OffsetTop are very negative.
2491 }
2492 #endif
2493 
2494 // Eliminate trivially redundant StoreCMs and accumulate their
2495 // precedence edges.
2496 void Compile::eliminate_redundant_card_marks(Node* n) {
2497   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2498   if (n->in(MemNode::Address)->outcnt() > 1) {
2499     // There are multiple users of the same address so it might be
2500     // possible to eliminate some of the StoreCMs
2501     Node* mem = n->in(MemNode::Memory);
2502     Node* adr = n->in(MemNode::Address);
2503     Node* val = n->in(MemNode::ValueIn);
2504     Node* prev = n;
2505     bool done = false;
2506     // Walk the chain of StoreCMs eliminating ones that match.  As
2507     // long as it's a chain of single users then the optimization is
2508     // safe.  Eliminating partially redundant StoreCMs would require
2509     // cloning copies down the other paths.
2510     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2511       if (adr == mem->in(MemNode::Address) &&
2512           val == mem->in(MemNode::ValueIn)) {
2513         // redundant StoreCM
2514         if (mem->req() > MemNode::OopStore) {
2515           // Hasn't been processed by this code yet.
2516           n->add_prec(mem->in(MemNode::OopStore));
2517         } else {
2518           // Already converted to precedence edge
2519           for (uint i = mem->req(); i < mem->len(); i++) {
2520             // Accumulate any precedence edges
2521             if (mem->in(i) != NULL) {
2522               n->add_prec(mem->in(i));
2523             }
2524           }
2525           // Everything above this point has been processed.
2526           done = true;
2527         }
2528         // Eliminate the previous StoreCM
2529         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2530         assert(mem->outcnt() == 0, "should be dead");
2531         mem->disconnect_inputs(NULL, this);
2532       } else {
2533         prev = mem;
2534       }
2535       mem = prev->in(MemNode::Memory);
2536     }
2537   }
2538 }
2539 
2540 //------------------------------final_graph_reshaping_impl----------------------
2541 // Implement items 1-5 from final_graph_reshaping below.
2542 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2543 
2544   if ( n->outcnt() == 0 ) return; // dead node
2545   uint nop = n->Opcode();
2546 
2547   // Check for 2-input instruction with "last use" on right input.
2548   // Swap to left input.  Implements item (2).
2549   if( n->req() == 3 &&          // two-input instruction
2550       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2551       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2552       n->in(2)->outcnt() == 1 &&// right use IS a last use
2553       !n->in(2)->is_Con() ) {   // right use is not a constant
2554     // Check for commutative opcode
2555     switch( nop ) {
2556     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2557     case Op_MaxI:  case Op_MinI:
2558     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2559     case Op_AndL:  case Op_XorL:  case Op_OrL:
2560     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2561       // Move "last use" input to left by swapping inputs
2562       n->swap_edges(1, 2);
2563       break;
2564     }
2565     default:
2566       break;
2567     }
2568   }
2569 
2570 #ifdef ASSERT
2571   if( n->is_Mem() ) {
2572     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2573     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2574             // oop will be recorded in oop map if load crosses safepoint
2575             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2576                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2577             "raw memory operations should have control edge");
2578   }
2579 #endif
2580   // Count FPU ops and common calls, implements item (3)
2581   switch( nop ) {
2582   // Count all float operations that may use FPU
2583   case Op_AddF:
2584   case Op_SubF:
2585   case Op_MulF:
2586   case Op_DivF:
2587   case Op_NegF:
2588   case Op_ModF:
2589   case Op_ConvI2F:
2590   case Op_ConF:
2591   case Op_CmpF:
2592   case Op_CmpF3:
2593   // case Op_ConvL2F: // longs are split into 32-bit halves
2594     frc.inc_float_count();
2595     break;
2596 
2597   case Op_ConvF2D:
2598   case Op_ConvD2F:
2599     frc.inc_float_count();
2600     frc.inc_double_count();
2601     break;
2602 
2603   // Count all double operations that may use FPU
2604   case Op_AddD:
2605   case Op_SubD:
2606   case Op_MulD:
2607   case Op_DivD:
2608   case Op_NegD:
2609   case Op_ModD:
2610   case Op_ConvI2D:
2611   case Op_ConvD2I:
2612   // case Op_ConvL2D: // handled by leaf call
2613   // case Op_ConvD2L: // handled by leaf call
2614   case Op_ConD:
2615   case Op_CmpD:
2616   case Op_CmpD3:
2617     frc.inc_double_count();
2618     break;
2619   case Op_Opaque1:              // Remove Opaque Nodes before matching
2620   case Op_Opaque2:              // Remove Opaque Nodes before matching
2621   case Op_Opaque3:
2622     n->subsume_by(n->in(1), this);
2623     break;
2624   case Op_CallStaticJava:
2625   case Op_CallJava:
2626   case Op_CallDynamicJava:
2627     frc.inc_java_call_count(); // Count java call site;
2628   case Op_CallRuntime:
2629   case Op_CallLeaf:
2630   case Op_CallLeafNoFP: {
2631     assert( n->is_Call(), "" );
2632     CallNode *call = n->as_Call();
2633     // Count call sites where the FP mode bit would have to be flipped.
2634     // Do not count uncommon runtime calls:
2635     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2636     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2637     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2638       frc.inc_call_count();   // Count the call site
2639     } else {                  // See if uncommon argument is shared
2640       Node *n = call->in(TypeFunc::Parms);
2641       int nop = n->Opcode();
2642       // Clone shared simple arguments to uncommon calls, item (1).
2643       if( n->outcnt() > 1 &&
2644           !n->is_Proj() &&
2645           nop != Op_CreateEx &&
2646           nop != Op_CheckCastPP &&
2647           nop != Op_DecodeN &&
2648           nop != Op_DecodeNKlass &&
2649           !n->is_Mem() ) {
2650         Node *x = n->clone();
2651         call->set_req( TypeFunc::Parms, x );
2652       }
2653     }
2654     break;
2655   }
2656 
2657   case Op_StoreD:
2658   case Op_LoadD:
2659   case Op_LoadD_unaligned:
2660     frc.inc_double_count();
2661     goto handle_mem;
2662   case Op_StoreF:
2663   case Op_LoadF:
2664     frc.inc_float_count();
2665     goto handle_mem;
2666 
2667   case Op_StoreCM:
2668     {
2669       // Convert OopStore dependence into precedence edge
2670       Node* prec = n->in(MemNode::OopStore);
2671       n->del_req(MemNode::OopStore);
2672       n->add_prec(prec);
2673       eliminate_redundant_card_marks(n);
2674     }
2675 
2676     // fall through
2677 
2678   case Op_StoreB:
2679   case Op_StoreC:
2680   case Op_StorePConditional:
2681   case Op_StoreI:
2682   case Op_StoreL:
2683   case Op_StoreIConditional:
2684   case Op_StoreLConditional:
2685   case Op_CompareAndSwapI:
2686   case Op_CompareAndSwapL:
2687   case Op_CompareAndSwapP:
2688   case Op_CompareAndSwapN:
2689   case Op_GetAndAddI:
2690   case Op_GetAndAddL:
2691   case Op_GetAndSetI:
2692   case Op_GetAndSetL:
2693   case Op_GetAndSetP:
2694   case Op_GetAndSetN:
2695   case Op_StoreP:
2696   case Op_StoreN:
2697   case Op_StoreNKlass:
2698   case Op_LoadB:
2699   case Op_LoadUB:
2700   case Op_LoadUS:
2701   case Op_LoadI:
2702   case Op_LoadKlass:
2703   case Op_LoadNKlass:
2704   case Op_LoadL:
2705   case Op_LoadL_unaligned:
2706   case Op_LoadPLocked:
2707   case Op_LoadP:
2708   case Op_LoadN:
2709   case Op_LoadRange:
2710   case Op_LoadS: {
2711   handle_mem:
2712 #ifdef ASSERT
2713     if( VerifyOptoOopOffsets ) {
2714       assert( n->is_Mem(), "" );
2715       MemNode *mem  = (MemNode*)n;
2716       // Check to see if address types have grounded out somehow.
2717       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2718       assert( !tp || oop_offset_is_sane(tp), "" );
2719     }
2720 #endif
2721     break;
2722   }
2723 
2724   case Op_AddP: {               // Assert sane base pointers
2725     Node *addp = n->in(AddPNode::Address);
2726     assert( !addp->is_AddP() ||
2727             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2728             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2729             "Base pointers must match" );
2730 #ifdef _LP64
2731     if ((UseCompressedOops || UseCompressedClassPointers) &&
2732         addp->Opcode() == Op_ConP &&
2733         addp == n->in(AddPNode::Base) &&
2734         n->in(AddPNode::Offset)->is_Con()) {
2735       // Use addressing with narrow klass to load with offset on x86.
2736       // On sparc loading 32-bits constant and decoding it have less
2737       // instructions (4) then load 64-bits constant (7).
2738       // Do this transformation here since IGVN will convert ConN back to ConP.
2739       const Type* t = addp->bottom_type();
2740       if (t->isa_oopptr() || t->isa_klassptr()) {
2741         Node* nn = NULL;
2742 
2743         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2744 
2745         // Look for existing ConN node of the same exact type.
2746         Node* r  = root();
2747         uint cnt = r->outcnt();
2748         for (uint i = 0; i < cnt; i++) {
2749           Node* m = r->raw_out(i);
2750           if (m!= NULL && m->Opcode() == op &&
2751               m->bottom_type()->make_ptr() == t) {
2752             nn = m;
2753             break;
2754           }
2755         }
2756         if (nn != NULL) {
2757           // Decode a narrow oop to match address
2758           // [R12 + narrow_oop_reg<<3 + offset]
2759           if (t->isa_oopptr()) {
2760             nn = new DecodeNNode(nn, t);
2761           } else {
2762             nn = new DecodeNKlassNode(nn, t);
2763           }
2764           n->set_req(AddPNode::Base, nn);
2765           n->set_req(AddPNode::Address, nn);
2766           if (addp->outcnt() == 0) {
2767             addp->disconnect_inputs(NULL, this);
2768           }
2769         }
2770       }
2771     }
2772 #endif
2773     break;
2774   }
2775 
2776 #ifdef _LP64
2777   case Op_CastPP:
2778     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2779       Node* in1 = n->in(1);
2780       const Type* t = n->bottom_type();
2781       Node* new_in1 = in1->clone();
2782       new_in1->as_DecodeN()->set_type(t);
2783 
2784       if (!Matcher::narrow_oop_use_complex_address()) {
2785         //
2786         // x86, ARM and friends can handle 2 adds in addressing mode
2787         // and Matcher can fold a DecodeN node into address by using
2788         // a narrow oop directly and do implicit NULL check in address:
2789         //
2790         // [R12 + narrow_oop_reg<<3 + offset]
2791         // NullCheck narrow_oop_reg
2792         //
2793         // On other platforms (Sparc) we have to keep new DecodeN node and
2794         // use it to do implicit NULL check in address:
2795         //
2796         // decode_not_null narrow_oop_reg, base_reg
2797         // [base_reg + offset]
2798         // NullCheck base_reg
2799         //
2800         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2801         // to keep the information to which NULL check the new DecodeN node
2802         // corresponds to use it as value in implicit_null_check().
2803         //
2804         new_in1->set_req(0, n->in(0));
2805       }
2806 
2807       n->subsume_by(new_in1, this);
2808       if (in1->outcnt() == 0) {
2809         in1->disconnect_inputs(NULL, this);
2810       }
2811     }
2812     break;
2813 
2814   case Op_CmpP:
2815     // Do this transformation here to preserve CmpPNode::sub() and
2816     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2817     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2818       Node* in1 = n->in(1);
2819       Node* in2 = n->in(2);
2820       if (!in1->is_DecodeNarrowPtr()) {
2821         in2 = in1;
2822         in1 = n->in(2);
2823       }
2824       assert(in1->is_DecodeNarrowPtr(), "sanity");
2825 
2826       Node* new_in2 = NULL;
2827       if (in2->is_DecodeNarrowPtr()) {
2828         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2829         new_in2 = in2->in(1);
2830       } else if (in2->Opcode() == Op_ConP) {
2831         const Type* t = in2->bottom_type();
2832         if (t == TypePtr::NULL_PTR) {
2833           assert(in1->is_DecodeN(), "compare klass to null?");
2834           // Don't convert CmpP null check into CmpN if compressed
2835           // oops implicit null check is not generated.
2836           // This will allow to generate normal oop implicit null check.
2837           if (Matcher::gen_narrow_oop_implicit_null_checks())
2838             new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2839           //
2840           // This transformation together with CastPP transformation above
2841           // will generated code for implicit NULL checks for compressed oops.
2842           //
2843           // The original code after Optimize()
2844           //
2845           //    LoadN memory, narrow_oop_reg
2846           //    decode narrow_oop_reg, base_reg
2847           //    CmpP base_reg, NULL
2848           //    CastPP base_reg // NotNull
2849           //    Load [base_reg + offset], val_reg
2850           //
2851           // after these transformations will be
2852           //
2853           //    LoadN memory, narrow_oop_reg
2854           //    CmpN narrow_oop_reg, NULL
2855           //    decode_not_null narrow_oop_reg, base_reg
2856           //    Load [base_reg + offset], val_reg
2857           //
2858           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2859           // since narrow oops can be used in debug info now (see the code in
2860           // final_graph_reshaping_walk()).
2861           //
2862           // At the end the code will be matched to
2863           // on x86:
2864           //
2865           //    Load_narrow_oop memory, narrow_oop_reg
2866           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2867           //    NullCheck narrow_oop_reg
2868           //
2869           // and on sparc:
2870           //
2871           //    Load_narrow_oop memory, narrow_oop_reg
2872           //    decode_not_null narrow_oop_reg, base_reg
2873           //    Load [base_reg + offset], val_reg
2874           //    NullCheck base_reg
2875           //
2876         } else if (t->isa_oopptr()) {
2877           new_in2 = ConNode::make(this, t->make_narrowoop());
2878         } else if (t->isa_klassptr()) {
2879           new_in2 = ConNode::make(this, t->make_narrowklass());
2880         }
2881       }
2882       if (new_in2 != NULL) {
2883         Node* cmpN = new CmpNNode(in1->in(1), new_in2);
2884         n->subsume_by(cmpN, this);
2885         if (in1->outcnt() == 0) {
2886           in1->disconnect_inputs(NULL, this);
2887         }
2888         if (in2->outcnt() == 0) {
2889           in2->disconnect_inputs(NULL, this);
2890         }
2891       }
2892     }
2893     break;
2894 
2895   case Op_DecodeN:
2896   case Op_DecodeNKlass:
2897     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2898     // DecodeN could be pinned when it can't be fold into
2899     // an address expression, see the code for Op_CastPP above.
2900     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2901     break;
2902 
2903   case Op_EncodeP:
2904   case Op_EncodePKlass: {
2905     Node* in1 = n->in(1);
2906     if (in1->is_DecodeNarrowPtr()) {
2907       n->subsume_by(in1->in(1), this);
2908     } else if (in1->Opcode() == Op_ConP) {
2909       const Type* t = in1->bottom_type();
2910       if (t == TypePtr::NULL_PTR) {
2911         assert(t->isa_oopptr(), "null klass?");
2912         n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2913       } else if (t->isa_oopptr()) {
2914         n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2915       } else if (t->isa_klassptr()) {
2916         n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2917       }
2918     }
2919     if (in1->outcnt() == 0) {
2920       in1->disconnect_inputs(NULL, this);
2921     }
2922     break;
2923   }
2924 
2925   case Op_Proj: {
2926     if (OptimizeStringConcat) {
2927       ProjNode* p = n->as_Proj();
2928       if (p->_is_io_use) {
2929         // Separate projections were used for the exception path which
2930         // are normally removed by a late inline.  If it wasn't inlined
2931         // then they will hang around and should just be replaced with
2932         // the original one.
2933         Node* proj = NULL;
2934         // Replace with just one
2935         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2936           Node *use = i.get();
2937           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2938             proj = use;
2939             break;
2940           }
2941         }
2942         assert(proj != NULL, "must be found");
2943         p->subsume_by(proj, this);
2944       }
2945     }
2946     break;
2947   }
2948 
2949   case Op_Phi:
2950     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2951       // The EncodeP optimization may create Phi with the same edges
2952       // for all paths. It is not handled well by Register Allocator.
2953       Node* unique_in = n->in(1);
2954       assert(unique_in != NULL, "");
2955       uint cnt = n->req();
2956       for (uint i = 2; i < cnt; i++) {
2957         Node* m = n->in(i);
2958         assert(m != NULL, "");
2959         if (unique_in != m)
2960           unique_in = NULL;
2961       }
2962       if (unique_in != NULL) {
2963         n->subsume_by(unique_in, this);
2964       }
2965     }
2966     break;
2967 
2968 #endif
2969 
2970   case Op_ModI:
2971     if (UseDivMod) {
2972       // Check if a%b and a/b both exist
2973       Node* d = n->find_similar(Op_DivI);
2974       if (d) {
2975         // Replace them with a fused divmod if supported
2976         if (Matcher::has_match_rule(Op_DivModI)) {
2977           DivModINode* divmod = DivModINode::make(this, n);
2978           d->subsume_by(divmod->div_proj(), this);
2979           n->subsume_by(divmod->mod_proj(), this);
2980         } else {
2981           // replace a%b with a-((a/b)*b)
2982           Node* mult = new MulINode(d, d->in(2));
2983           Node* sub  = new SubINode(d->in(1), mult);
2984           n->subsume_by(sub, this);
2985         }
2986       }
2987     }
2988     break;
2989 
2990   case Op_ModL:
2991     if (UseDivMod) {
2992       // Check if a%b and a/b both exist
2993       Node* d = n->find_similar(Op_DivL);
2994       if (d) {
2995         // Replace them with a fused divmod if supported
2996         if (Matcher::has_match_rule(Op_DivModL)) {
2997           DivModLNode* divmod = DivModLNode::make(this, n);
2998           d->subsume_by(divmod->div_proj(), this);
2999           n->subsume_by(divmod->mod_proj(), this);
3000         } else {
3001           // replace a%b with a-((a/b)*b)
3002           Node* mult = new MulLNode(d, d->in(2));
3003           Node* sub  = new SubLNode(d->in(1), mult);
3004           n->subsume_by(sub, this);
3005         }
3006       }
3007     }
3008     break;
3009 
3010   case Op_LoadVector:
3011   case Op_StoreVector:
3012     break;
3013 
3014   case Op_PackB:
3015   case Op_PackS:
3016   case Op_PackI:
3017   case Op_PackF:
3018   case Op_PackL:
3019   case Op_PackD:
3020     if (n->req()-1 > 2) {
3021       // Replace many operand PackNodes with a binary tree for matching
3022       PackNode* p = (PackNode*) n;
3023       Node* btp = p->binary_tree_pack(this, 1, n->req());
3024       n->subsume_by(btp, this);
3025     }
3026     break;
3027   case Op_Loop:
3028   case Op_CountedLoop:
3029     if (n->as_Loop()->is_inner_loop()) {
3030       frc.inc_inner_loop_count();
3031     }
3032     break;
3033   case Op_LShiftI:
3034   case Op_RShiftI:
3035   case Op_URShiftI:
3036   case Op_LShiftL:
3037   case Op_RShiftL:
3038   case Op_URShiftL:
3039     if (Matcher::need_masked_shift_count) {
3040       // The cpu's shift instructions don't restrict the count to the
3041       // lower 5/6 bits. We need to do the masking ourselves.
3042       Node* in2 = n->in(2);
3043       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3044       const TypeInt* t = in2->find_int_type();
3045       if (t != NULL && t->is_con()) {
3046         juint shift = t->get_con();
3047         if (shift > mask) { // Unsigned cmp
3048           n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
3049         }
3050       } else {
3051         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3052           Node* shift = new AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
3053           n->set_req(2, shift);
3054         }
3055       }
3056       if (in2->outcnt() == 0) { // Remove dead node
3057         in2->disconnect_inputs(NULL, this);
3058       }
3059     }
3060     break;
3061   case Op_MemBarStoreStore:
3062   case Op_MemBarRelease:
3063     // Break the link with AllocateNode: it is no longer useful and
3064     // confuses register allocation.
3065     if (n->req() > MemBarNode::Precedent) {
3066       n->set_req(MemBarNode::Precedent, top());
3067     }
3068     break;
3069   default:
3070     assert( !n->is_Call(), "" );
3071     assert( !n->is_Mem(), "" );
3072     break;
3073   }
3074 
3075   // Collect CFG split points
3076   if (n->is_MultiBranch())
3077     frc._tests.push(n);
3078 }
3079 
3080 //------------------------------final_graph_reshaping_walk---------------------
3081 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3082 // requires that the walk visits a node's inputs before visiting the node.
3083 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3084   ResourceArea *area = Thread::current()->resource_area();
3085   Unique_Node_List sfpt(area);
3086 
3087   frc._visited.set(root->_idx); // first, mark node as visited
3088   uint cnt = root->req();
3089   Node *n = root;
3090   uint  i = 0;
3091   while (true) {
3092     if (i < cnt) {
3093       // Place all non-visited non-null inputs onto stack
3094       Node* m = n->in(i);
3095       ++i;
3096       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3097         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3098           // compute worst case interpreter size in case of a deoptimization
3099           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3100 
3101           sfpt.push(m);
3102         }
3103         cnt = m->req();
3104         nstack.push(n, i); // put on stack parent and next input's index
3105         n = m;
3106         i = 0;
3107       }
3108     } else {
3109       // Now do post-visit work
3110       final_graph_reshaping_impl( n, frc );
3111       if (nstack.is_empty())
3112         break;             // finished
3113       n = nstack.node();   // Get node from stack
3114       cnt = n->req();
3115       i = nstack.index();
3116       nstack.pop();        // Shift to the next node on stack
3117     }
3118   }
3119 
3120   // Skip next transformation if compressed oops are not used.
3121   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3122       (!UseCompressedOops && !UseCompressedClassPointers))
3123     return;
3124 
3125   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3126   // It could be done for an uncommon traps or any safepoints/calls
3127   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3128   while (sfpt.size() > 0) {
3129     n = sfpt.pop();
3130     JVMState *jvms = n->as_SafePoint()->jvms();
3131     assert(jvms != NULL, "sanity");
3132     int start = jvms->debug_start();
3133     int end   = n->req();
3134     bool is_uncommon = (n->is_CallStaticJava() &&
3135                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3136     for (int j = start; j < end; j++) {
3137       Node* in = n->in(j);
3138       if (in->is_DecodeNarrowPtr()) {
3139         bool safe_to_skip = true;
3140         if (!is_uncommon ) {
3141           // Is it safe to skip?
3142           for (uint i = 0; i < in->outcnt(); i++) {
3143             Node* u = in->raw_out(i);
3144             if (!u->is_SafePoint() ||
3145                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3146               safe_to_skip = false;
3147             }
3148           }
3149         }
3150         if (safe_to_skip) {
3151           n->set_req(j, in->in(1));
3152         }
3153         if (in->outcnt() == 0) {
3154           in->disconnect_inputs(NULL, this);
3155         }
3156       }
3157     }
3158   }
3159 }
3160 
3161 //------------------------------final_graph_reshaping--------------------------
3162 // Final Graph Reshaping.
3163 //
3164 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3165 //     and not commoned up and forced early.  Must come after regular
3166 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3167 //     inputs to Loop Phis; these will be split by the allocator anyways.
3168 //     Remove Opaque nodes.
3169 // (2) Move last-uses by commutative operations to the left input to encourage
3170 //     Intel update-in-place two-address operations and better register usage
3171 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3172 //     calls canonicalizing them back.
3173 // (3) Count the number of double-precision FP ops, single-precision FP ops
3174 //     and call sites.  On Intel, we can get correct rounding either by
3175 //     forcing singles to memory (requires extra stores and loads after each
3176 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3177 //     clearing the mode bit around call sites).  The mode bit is only used
3178 //     if the relative frequency of single FP ops to calls is low enough.
3179 //     This is a key transform for SPEC mpeg_audio.
3180 // (4) Detect infinite loops; blobs of code reachable from above but not
3181 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3182 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3183 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3184 //     Detection is by looking for IfNodes where only 1 projection is
3185 //     reachable from below or CatchNodes missing some targets.
3186 // (5) Assert for insane oop offsets in debug mode.
3187 
3188 bool Compile::final_graph_reshaping() {
3189   // an infinite loop may have been eliminated by the optimizer,
3190   // in which case the graph will be empty.
3191   if (root()->req() == 1) {
3192     record_method_not_compilable("trivial infinite loop");
3193     return true;
3194   }
3195 
3196   // Expensive nodes have their control input set to prevent the GVN
3197   // from freely commoning them. There's no GVN beyond this point so
3198   // no need to keep the control input. We want the expensive nodes to
3199   // be freely moved to the least frequent code path by gcm.
3200   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3201   for (int i = 0; i < expensive_count(); i++) {
3202     _expensive_nodes->at(i)->set_req(0, NULL);
3203   }
3204 
3205   Final_Reshape_Counts frc;
3206 
3207   // Visit everybody reachable!
3208   // Allocate stack of size C->unique()/2 to avoid frequent realloc
3209   Node_Stack nstack(unique() >> 1);
3210   final_graph_reshaping_walk(nstack, root(), frc);
3211 
3212   // Check for unreachable (from below) code (i.e., infinite loops).
3213   for( uint i = 0; i < frc._tests.size(); i++ ) {
3214     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3215     // Get number of CFG targets.
3216     // Note that PCTables include exception targets after calls.
3217     uint required_outcnt = n->required_outcnt();
3218     if (n->outcnt() != required_outcnt) {
3219       // Check for a few special cases.  Rethrow Nodes never take the
3220       // 'fall-thru' path, so expected kids is 1 less.
3221       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3222         if (n->in(0)->in(0)->is_Call()) {
3223           CallNode *call = n->in(0)->in(0)->as_Call();
3224           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3225             required_outcnt--;      // Rethrow always has 1 less kid
3226           } else if (call->req() > TypeFunc::Parms &&
3227                      call->is_CallDynamicJava()) {
3228             // Check for null receiver. In such case, the optimizer has
3229             // detected that the virtual call will always result in a null
3230             // pointer exception. The fall-through projection of this CatchNode
3231             // will not be populated.
3232             Node *arg0 = call->in(TypeFunc::Parms);
3233             if (arg0->is_Type() &&
3234                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3235               required_outcnt--;
3236             }
3237           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3238                      call->req() > TypeFunc::Parms+1 &&
3239                      call->is_CallStaticJava()) {
3240             // Check for negative array length. In such case, the optimizer has
3241             // detected that the allocation attempt will always result in an
3242             // exception. There is no fall-through projection of this CatchNode .
3243             Node *arg1 = call->in(TypeFunc::Parms+1);
3244             if (arg1->is_Type() &&
3245                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3246               required_outcnt--;
3247             }
3248           }
3249         }
3250       }
3251       // Recheck with a better notion of 'required_outcnt'
3252       if (n->outcnt() != required_outcnt) {
3253         record_method_not_compilable("malformed control flow");
3254         return true;            // Not all targets reachable!
3255       }
3256     }
3257     // Check that I actually visited all kids.  Unreached kids
3258     // must be infinite loops.
3259     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3260       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3261         record_method_not_compilable("infinite loop");
3262         return true;            // Found unvisited kid; must be unreach
3263       }
3264   }
3265 
3266   // If original bytecodes contained a mixture of floats and doubles
3267   // check if the optimizer has made it homogenous, item (3).
3268   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3269       frc.get_float_count() > 32 &&
3270       frc.get_double_count() == 0 &&
3271       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3272     set_24_bit_selection_and_mode( false,  true );
3273   }
3274 
3275   set_java_calls(frc.get_java_call_count());
3276   set_inner_loops(frc.get_inner_loop_count());
3277 
3278   // No infinite loops, no reason to bail out.
3279   return false;
3280 }
3281 
3282 //-----------------------------too_many_traps----------------------------------
3283 // Report if there are too many traps at the current method and bci.
3284 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3285 bool Compile::too_many_traps(ciMethod* method,
3286                              int bci,
3287                              Deoptimization::DeoptReason reason) {
3288   ciMethodData* md = method->method_data();
3289   if (md->is_empty()) {
3290     // Assume the trap has not occurred, or that it occurred only
3291     // because of a transient condition during start-up in the interpreter.
3292     return false;
3293   }
3294   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3295   if (md->has_trap_at(bci, m, reason) != 0) {
3296     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3297     // Also, if there are multiple reasons, or if there is no per-BCI record,
3298     // assume the worst.
3299     if (log())
3300       log()->elem("observe trap='%s' count='%d'",
3301                   Deoptimization::trap_reason_name(reason),
3302                   md->trap_count(reason));
3303     return true;
3304   } else {
3305     // Ignore method/bci and see if there have been too many globally.
3306     return too_many_traps(reason, md);
3307   }
3308 }
3309 
3310 // Less-accurate variant which does not require a method and bci.
3311 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3312                              ciMethodData* logmd) {
3313   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3314     // Too many traps globally.
3315     // Note that we use cumulative trap_count, not just md->trap_count.
3316     if (log()) {
3317       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3318       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3319                   Deoptimization::trap_reason_name(reason),
3320                   mcount, trap_count(reason));
3321     }
3322     return true;
3323   } else {
3324     // The coast is clear.
3325     return false;
3326   }
3327 }
3328 
3329 //--------------------------too_many_recompiles--------------------------------
3330 // Report if there are too many recompiles at the current method and bci.
3331 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3332 // Is not eager to return true, since this will cause the compiler to use
3333 // Action_none for a trap point, to avoid too many recompilations.
3334 bool Compile::too_many_recompiles(ciMethod* method,
3335                                   int bci,
3336                                   Deoptimization::DeoptReason reason) {
3337   ciMethodData* md = method->method_data();
3338   if (md->is_empty()) {
3339     // Assume the trap has not occurred, or that it occurred only
3340     // because of a transient condition during start-up in the interpreter.
3341     return false;
3342   }
3343   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3344   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3345   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3346   Deoptimization::DeoptReason per_bc_reason
3347     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3348   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3349   if ((per_bc_reason == Deoptimization::Reason_none
3350        || md->has_trap_at(bci, m, reason) != 0)
3351       // The trap frequency measure we care about is the recompile count:
3352       && md->trap_recompiled_at(bci, m)
3353       && md->overflow_recompile_count() >= bc_cutoff) {
3354     // Do not emit a trap here if it has already caused recompilations.
3355     // Also, if there are multiple reasons, or if there is no per-BCI record,
3356     // assume the worst.
3357     if (log())
3358       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3359                   Deoptimization::trap_reason_name(reason),
3360                   md->trap_count(reason),
3361                   md->overflow_recompile_count());
3362     return true;
3363   } else if (trap_count(reason) != 0
3364              && decompile_count() >= m_cutoff) {
3365     // Too many recompiles globally, and we have seen this sort of trap.
3366     // Use cumulative decompile_count, not just md->decompile_count.
3367     if (log())
3368       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3369                   Deoptimization::trap_reason_name(reason),
3370                   md->trap_count(reason), trap_count(reason),
3371                   md->decompile_count(), decompile_count());
3372     return true;
3373   } else {
3374     // The coast is clear.
3375     return false;
3376   }
3377 }
3378 
3379 // Compute when not to trap. Used by matching trap based nodes and
3380 // NullCheck optimization.
3381 void Compile::set_allowed_deopt_reasons() {
3382   _allowed_reasons = 0;
3383   if (is_method_compilation()) {
3384     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3385       assert(rs < BitsPerInt, "recode bit map");
3386       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3387         _allowed_reasons |= nth_bit(rs);
3388       }
3389     }
3390   }
3391 }
3392 
3393 #ifndef PRODUCT
3394 //------------------------------verify_graph_edges---------------------------
3395 // Walk the Graph and verify that there is a one-to-one correspondence
3396 // between Use-Def edges and Def-Use edges in the graph.
3397 void Compile::verify_graph_edges(bool no_dead_code) {
3398   if (VerifyGraphEdges) {
3399     ResourceArea *area = Thread::current()->resource_area();
3400     Unique_Node_List visited(area);
3401     // Call recursive graph walk to check edges
3402     _root->verify_edges(visited);
3403     if (no_dead_code) {
3404       // Now make sure that no visited node is used by an unvisited node.
3405       bool dead_nodes = 0;
3406       Unique_Node_List checked(area);
3407       while (visited.size() > 0) {
3408         Node* n = visited.pop();
3409         checked.push(n);
3410         for (uint i = 0; i < n->outcnt(); i++) {
3411           Node* use = n->raw_out(i);
3412           if (checked.member(use))  continue;  // already checked
3413           if (visited.member(use))  continue;  // already in the graph
3414           if (use->is_Con())        continue;  // a dead ConNode is OK
3415           // At this point, we have found a dead node which is DU-reachable.
3416           if (dead_nodes++ == 0)
3417             tty->print_cr("*** Dead nodes reachable via DU edges:");
3418           use->dump(2);
3419           tty->print_cr("---");
3420           checked.push(use);  // No repeats; pretend it is now checked.
3421         }
3422       }
3423       assert(dead_nodes == 0, "using nodes must be reachable from root");
3424     }
3425   }
3426 }
3427 
3428 // Verify GC barriers consistency
3429 // Currently supported:
3430 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3431 void Compile::verify_barriers() {
3432   if (UseG1GC) {
3433     // Verify G1 pre-barriers
3434     const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3435 
3436     ResourceArea *area = Thread::current()->resource_area();
3437     Unique_Node_List visited(area);
3438     Node_List worklist(area);
3439     // We're going to walk control flow backwards starting from the Root
3440     worklist.push(_root);
3441     while (worklist.size() > 0) {
3442       Node* x = worklist.pop();
3443       if (x == NULL || x == top()) continue;
3444       if (visited.member(x)) {
3445         continue;
3446       } else {
3447         visited.push(x);
3448       }
3449 
3450       if (x->is_Region()) {
3451         for (uint i = 1; i < x->req(); i++) {
3452           worklist.push(x->in(i));
3453         }
3454       } else {
3455         worklist.push(x->in(0));
3456         // We are looking for the pattern:
3457         //                            /->ThreadLocal
3458         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3459         //              \->ConI(0)
3460         // We want to verify that the If and the LoadB have the same control
3461         // See GraphKit::g1_write_barrier_pre()
3462         if (x->is_If()) {
3463           IfNode *iff = x->as_If();
3464           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3465             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3466             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3467                 && cmp->in(1)->is_Load()) {
3468               LoadNode* load = cmp->in(1)->as_Load();
3469               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3470                   && load->in(2)->in(3)->is_Con()
3471                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3472 
3473                 Node* if_ctrl = iff->in(0);
3474                 Node* load_ctrl = load->in(0);
3475 
3476                 if (if_ctrl != load_ctrl) {
3477                   // Skip possible CProj->NeverBranch in infinite loops
3478                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3479                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3480                     if_ctrl = if_ctrl->in(0)->in(0);
3481                   }
3482                 }
3483                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3484               }
3485             }
3486           }
3487         }
3488       }
3489     }
3490   }
3491 }
3492 
3493 #endif
3494 
3495 // The Compile object keeps track of failure reasons separately from the ciEnv.
3496 // This is required because there is not quite a 1-1 relation between the
3497 // ciEnv and its compilation task and the Compile object.  Note that one
3498 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3499 // to backtrack and retry without subsuming loads.  Other than this backtracking
3500 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3501 // by the logic in C2Compiler.
3502 void Compile::record_failure(const char* reason) {
3503   if (log() != NULL) {
3504     log()->elem("failure reason='%s' phase='compile'", reason);
3505   }
3506   if (_failure_reason == NULL) {
3507     // Record the first failure reason.
3508     _failure_reason = reason;
3509   }
3510 
3511   EventCompilerFailure event;
3512   if (event.should_commit()) {
3513     event.set_compileID(Compile::compile_id());
3514     event.set_failure(reason);
3515     event.commit();
3516   }
3517 
3518   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3519     C->print_method(PHASE_FAILURE);
3520   }
3521   _root = NULL;  // flush the graph, too
3522 }
3523 
3524 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3525   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3526     _phase_name(name), _dolog(dolog)
3527 {
3528   if (dolog) {
3529     C = Compile::current();
3530     _log = C->log();
3531   } else {
3532     C = NULL;
3533     _log = NULL;
3534   }
3535   if (_log != NULL) {
3536     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3537     _log->stamp();
3538     _log->end_head();
3539   }
3540 }
3541 
3542 Compile::TracePhase::~TracePhase() {
3543 
3544   C = Compile::current();
3545   if (_dolog) {
3546     _log = C->log();
3547   } else {
3548     _log = NULL;
3549   }
3550 
3551 #ifdef ASSERT
3552   if (PrintIdealNodeCount) {
3553     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3554                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3555   }
3556 
3557   if (VerifyIdealNodeCount) {
3558     Compile::current()->print_missing_nodes();
3559   }
3560 #endif
3561 
3562   if (_log != NULL) {
3563     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3564   }
3565 }
3566 
3567 //=============================================================================
3568 // Two Constant's are equal when the type and the value are equal.
3569 bool Compile::Constant::operator==(const Constant& other) {
3570   if (type()          != other.type()         )  return false;
3571   if (can_be_reused() != other.can_be_reused())  return false;
3572   // For floating point values we compare the bit pattern.
3573   switch (type()) {
3574   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3575   case T_LONG:
3576   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3577   case T_OBJECT:
3578   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3579   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3580   case T_METADATA: return (_v._metadata == other._v._metadata);
3581   default: ShouldNotReachHere();
3582   }
3583   return false;
3584 }
3585 
3586 static int type_to_size_in_bytes(BasicType t) {
3587   switch (t) {
3588   case T_LONG:    return sizeof(jlong  );
3589   case T_FLOAT:   return sizeof(jfloat );
3590   case T_DOUBLE:  return sizeof(jdouble);
3591   case T_METADATA: return sizeof(Metadata*);
3592     // We use T_VOID as marker for jump-table entries (labels) which
3593     // need an internal word relocation.
3594   case T_VOID:
3595   case T_ADDRESS:
3596   case T_OBJECT:  return sizeof(jobject);
3597   }
3598 
3599   ShouldNotReachHere();
3600   return -1;
3601 }
3602 
3603 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3604   // sort descending
3605   if (a->freq() > b->freq())  return -1;
3606   if (a->freq() < b->freq())  return  1;
3607   return 0;
3608 }
3609 
3610 void Compile::ConstantTable::calculate_offsets_and_size() {
3611   // First, sort the array by frequencies.
3612   _constants.sort(qsort_comparator);
3613 
3614 #ifdef ASSERT
3615   // Make sure all jump-table entries were sorted to the end of the
3616   // array (they have a negative frequency).
3617   bool found_void = false;
3618   for (int i = 0; i < _constants.length(); i++) {
3619     Constant con = _constants.at(i);
3620     if (con.type() == T_VOID)
3621       found_void = true;  // jump-tables
3622     else
3623       assert(!found_void, "wrong sorting");
3624   }
3625 #endif
3626 
3627   int offset = 0;
3628   for (int i = 0; i < _constants.length(); i++) {
3629     Constant* con = _constants.adr_at(i);
3630 
3631     // Align offset for type.
3632     int typesize = type_to_size_in_bytes(con->type());
3633     offset = align_size_up(offset, typesize);
3634     con->set_offset(offset);   // set constant's offset
3635 
3636     if (con->type() == T_VOID) {
3637       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3638       offset = offset + typesize * n->outcnt();  // expand jump-table
3639     } else {
3640       offset = offset + typesize;
3641     }
3642   }
3643 
3644   // Align size up to the next section start (which is insts; see
3645   // CodeBuffer::align_at_start).
3646   assert(_size == -1, "already set?");
3647   _size = align_size_up(offset, CodeEntryAlignment);
3648 }
3649 
3650 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3651   MacroAssembler _masm(&cb);
3652   for (int i = 0; i < _constants.length(); i++) {
3653     Constant con = _constants.at(i);
3654     address constant_addr;
3655     switch (con.type()) {
3656     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3657     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3658     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3659     case T_OBJECT: {
3660       jobject obj = con.get_jobject();
3661       int oop_index = _masm.oop_recorder()->find_index(obj);
3662       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3663       break;
3664     }
3665     case T_ADDRESS: {
3666       address addr = (address) con.get_jobject();
3667       constant_addr = _masm.address_constant(addr);
3668       break;
3669     }
3670     // We use T_VOID as marker for jump-table entries (labels) which
3671     // need an internal word relocation.
3672     case T_VOID: {
3673       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3674       // Fill the jump-table with a dummy word.  The real value is
3675       // filled in later in fill_jump_table.
3676       address dummy = (address) n;
3677       constant_addr = _masm.address_constant(dummy);
3678       // Expand jump-table
3679       for (uint i = 1; i < n->outcnt(); i++) {
3680         address temp_addr = _masm.address_constant(dummy + i);
3681         assert(temp_addr, "consts section too small");
3682       }
3683       break;
3684     }
3685     case T_METADATA: {
3686       Metadata* obj = con.get_metadata();
3687       int metadata_index = _masm.oop_recorder()->find_index(obj);
3688       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3689       break;
3690     }
3691     default: ShouldNotReachHere();
3692     }
3693     assert(constant_addr, "consts section too small");
3694     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3695             err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3696   }
3697 }
3698 
3699 int Compile::ConstantTable::find_offset(Constant& con) const {
3700   int idx = _constants.find(con);
3701   assert(idx != -1, "constant must be in constant table");
3702   int offset = _constants.at(idx).offset();
3703   assert(offset != -1, "constant table not emitted yet?");
3704   return offset;
3705 }
3706 
3707 void Compile::ConstantTable::add(Constant& con) {
3708   if (con.can_be_reused()) {
3709     int idx = _constants.find(con);
3710     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3711       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3712       return;
3713     }
3714   }
3715   (void) _constants.append(con);
3716 }
3717 
3718 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3719   Block* b = Compile::current()->cfg()->get_block_for_node(n);
3720   Constant con(type, value, b->_freq);
3721   add(con);
3722   return con;
3723 }
3724 
3725 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3726   Constant con(metadata);
3727   add(con);
3728   return con;
3729 }
3730 
3731 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3732   jvalue value;
3733   BasicType type = oper->type()->basic_type();
3734   switch (type) {
3735   case T_LONG:    value.j = oper->constantL(); break;
3736   case T_FLOAT:   value.f = oper->constantF(); break;
3737   case T_DOUBLE:  value.d = oper->constantD(); break;
3738   case T_OBJECT:
3739   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3740   case T_METADATA: return add((Metadata*)oper->constant()); break;
3741   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3742   }
3743   return add(n, type, value);
3744 }
3745 
3746 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3747   jvalue value;
3748   // We can use the node pointer here to identify the right jump-table
3749   // as this method is called from Compile::Fill_buffer right before
3750   // the MachNodes are emitted and the jump-table is filled (means the
3751   // MachNode pointers do not change anymore).
3752   value.l = (jobject) n;
3753   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3754   add(con);
3755   return con;
3756 }
3757 
3758 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3759   // If called from Compile::scratch_emit_size do nothing.
3760   if (Compile::current()->in_scratch_emit_size())  return;
3761 
3762   assert(labels.is_nonempty(), "must be");
3763   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3764 
3765   // Since MachConstantNode::constant_offset() also contains
3766   // table_base_offset() we need to subtract the table_base_offset()
3767   // to get the plain offset into the constant table.
3768   int offset = n->constant_offset() - table_base_offset();
3769 
3770   MacroAssembler _masm(&cb);
3771   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3772 
3773   for (uint i = 0; i < n->outcnt(); i++) {
3774     address* constant_addr = &jump_table_base[i];
3775     assert(*constant_addr == (((address) n) + i), err_msg_res("all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, p2i(*constant_addr), p2i(((address) n) + i)));
3776     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3777     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3778   }
3779 }
3780 
3781 // The message about the current inlining is accumulated in
3782 // _print_inlining_stream and transfered into the _print_inlining_list
3783 // once we know whether inlining succeeds or not. For regular
3784 // inlining, messages are appended to the buffer pointed by
3785 // _print_inlining_idx in the _print_inlining_list. For late inlining,
3786 // a new buffer is added after _print_inlining_idx in the list. This
3787 // way we can update the inlining message for late inlining call site
3788 // when the inlining is attempted again.
3789 void Compile::print_inlining_init() {
3790   if (print_inlining() || print_intrinsics()) {
3791     _print_inlining_stream = new stringStream();
3792     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
3793   }
3794 }
3795 
3796 void Compile::print_inlining_reinit() {
3797   if (print_inlining() || print_intrinsics()) {
3798     // Re allocate buffer when we change ResourceMark
3799     _print_inlining_stream = new stringStream();
3800   }
3801 }
3802 
3803 void Compile::print_inlining_reset() {
3804   _print_inlining_stream->reset();
3805 }
3806 
3807 void Compile::print_inlining_commit() {
3808   assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
3809   // Transfer the message from _print_inlining_stream to the current
3810   // _print_inlining_list buffer and clear _print_inlining_stream.
3811   _print_inlining_list->at(_print_inlining_idx).ss()->write(_print_inlining_stream->as_string(), _print_inlining_stream->size());
3812   print_inlining_reset();
3813 }
3814 
3815 void Compile::print_inlining_push() {
3816   // Add new buffer to the _print_inlining_list at current position
3817   _print_inlining_idx++;
3818   _print_inlining_list->insert_before(_print_inlining_idx, PrintInliningBuffer());
3819 }
3820 
3821 Compile::PrintInliningBuffer& Compile::print_inlining_current() {
3822   return _print_inlining_list->at(_print_inlining_idx);
3823 }
3824 
3825 void Compile::print_inlining_update(CallGenerator* cg) {
3826   if (print_inlining() || print_intrinsics()) {
3827     if (!cg->is_late_inline()) {
3828       if (print_inlining_current().cg() != NULL) {
3829         print_inlining_push();
3830       }
3831       print_inlining_commit();
3832     } else {
3833       if (print_inlining_current().cg() != cg &&
3834           (print_inlining_current().cg() != NULL ||
3835            print_inlining_current().ss()->size() != 0)) {
3836         print_inlining_push();
3837       }
3838       print_inlining_commit();
3839       print_inlining_current().set_cg(cg);
3840     }
3841   }
3842 }
3843 
3844 void Compile::print_inlining_move_to(CallGenerator* cg) {
3845   // We resume inlining at a late inlining call site. Locate the
3846   // corresponding inlining buffer so that we can update it.
3847   if (print_inlining()) {
3848     for (int i = 0; i < _print_inlining_list->length(); i++) {
3849       if (_print_inlining_list->adr_at(i)->cg() == cg) {
3850         _print_inlining_idx = i;
3851         return;
3852       }
3853     }
3854     ShouldNotReachHere();
3855   }
3856 }
3857 
3858 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
3859   if (print_inlining()) {
3860     assert(_print_inlining_stream->size() > 0, "missing inlining msg");
3861     assert(print_inlining_current().cg() == cg, "wrong entry");
3862     // replace message with new message
3863     _print_inlining_list->at_put(_print_inlining_idx, PrintInliningBuffer());
3864     print_inlining_commit();
3865     print_inlining_current().set_cg(cg);
3866   }
3867 }
3868 
3869 void Compile::print_inlining_assert_ready() {
3870   assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
3871 }
3872 
3873 void Compile::process_print_inlining() {
3874   bool do_print_inlining = print_inlining() || print_intrinsics();
3875   if (do_print_inlining || log() != NULL) {
3876     // Print inlining message for candidates that we couldn't inline
3877     // for lack of space
3878     for (int i = 0; i < _late_inlines.length(); i++) {
3879       CallGenerator* cg = _late_inlines.at(i);
3880       if (!cg->is_mh_late_inline()) {
3881         const char* msg = "live nodes > LiveNodeCountInliningCutoff";
3882         if (do_print_inlining) {
3883           cg->print_inlining_late(msg);
3884         }
3885         log_late_inline_failure(cg, msg);
3886       }
3887     }
3888   }
3889   if (do_print_inlining) {
3890     ResourceMark rm;
3891     stringStream ss;
3892     for (int i = 0; i < _print_inlining_list->length(); i++) {
3893       ss.print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
3894     }
3895     size_t end = ss.size();
3896     _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
3897     strncpy(_print_inlining_output, ss.base(), end+1);
3898     _print_inlining_output[end] = 0;
3899   }
3900 }
3901 
3902 void Compile::dump_print_inlining() {
3903   if (_print_inlining_output != NULL) {
3904     tty->print_raw(_print_inlining_output);
3905   }
3906 }
3907 
3908 void Compile::log_late_inline(CallGenerator* cg) {
3909   if (log() != NULL) {
3910     log()->head("late_inline method='%d'  inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
3911                 cg->unique_id());
3912     JVMState* p = cg->call_node()->jvms();
3913     while (p != NULL) {
3914       log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
3915       p = p->caller();
3916     }
3917     log()->tail("late_inline");
3918   }
3919 }
3920 
3921 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
3922   log_late_inline(cg);
3923   if (log() != NULL) {
3924     log()->inline_fail(msg);
3925   }
3926 }
3927 
3928 void Compile::log_inline_id(CallGenerator* cg) {
3929   if (log() != NULL) {
3930     // The LogCompilation tool needs a unique way to identify late
3931     // inline call sites. This id must be unique for this call site in
3932     // this compilation. Try to have it unique across compilations as
3933     // well because it can be convenient when grepping through the log
3934     // file.
3935     // Distinguish OSR compilations from others in case CICountOSR is
3936     // on.
3937     jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
3938     cg->set_unique_id(id);
3939     log()->elem("inline_id id='" JLONG_FORMAT "'", id);
3940   }
3941 }
3942 
3943 void Compile::log_inline_failure(const char* msg) {
3944   if (C->log() != NULL) {
3945     C->log()->inline_fail(msg);
3946   }
3947 }
3948 
3949 
3950 // Dump inlining replay data to the stream.
3951 // Don't change thread state and acquire any locks.
3952 void Compile::dump_inline_data(outputStream* out) {
3953   InlineTree* inl_tree = ilt();
3954   if (inl_tree != NULL) {
3955     out->print(" inline %d", inl_tree->count());
3956     inl_tree->dump_replay_data(out);
3957   }
3958 }
3959 
3960 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3961   if (n1->Opcode() < n2->Opcode())      return -1;
3962   else if (n1->Opcode() > n2->Opcode()) return 1;
3963 
3964   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()));
3965   for (uint i = 1; i < n1->req(); i++) {
3966     if (n1->in(i) < n2->in(i))      return -1;
3967     else if (n1->in(i) > n2->in(i)) return 1;
3968   }
3969 
3970   return 0;
3971 }
3972 
3973 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3974   Node* n1 = *n1p;
3975   Node* n2 = *n2p;
3976 
3977   return cmp_expensive_nodes(n1, n2);
3978 }
3979 
3980 void Compile::sort_expensive_nodes() {
3981   if (!expensive_nodes_sorted()) {
3982     _expensive_nodes->sort(cmp_expensive_nodes);
3983   }
3984 }
3985 
3986 bool Compile::expensive_nodes_sorted() const {
3987   for (int i = 1; i < _expensive_nodes->length(); i++) {
3988     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
3989       return false;
3990     }
3991   }
3992   return true;
3993 }
3994 
3995 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
3996   if (_expensive_nodes->length() == 0) {
3997     return false;
3998   }
3999 
4000   assert(OptimizeExpensiveOps, "optimization off?");
4001 
4002   // Take this opportunity to remove dead nodes from the list
4003   int j = 0;
4004   for (int i = 0; i < _expensive_nodes->length(); i++) {
4005     Node* n = _expensive_nodes->at(i);
4006     if (!n->is_unreachable(igvn)) {
4007       assert(n->is_expensive(), "should be expensive");
4008       _expensive_nodes->at_put(j, n);
4009       j++;
4010     }
4011   }
4012   _expensive_nodes->trunc_to(j);
4013 
4014   // Then sort the list so that similar nodes are next to each other
4015   // and check for at least two nodes of identical kind with same data
4016   // inputs.
4017   sort_expensive_nodes();
4018 
4019   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
4020     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
4021       return true;
4022     }
4023   }
4024 
4025   return false;
4026 }
4027 
4028 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4029   if (_expensive_nodes->length() == 0) {
4030     return;
4031   }
4032 
4033   assert(OptimizeExpensiveOps, "optimization off?");
4034 
4035   // Sort to bring similar nodes next to each other and clear the
4036   // control input of nodes for which there's only a single copy.
4037   sort_expensive_nodes();
4038 
4039   int j = 0;
4040   int identical = 0;
4041   int i = 0;
4042   for (; i < _expensive_nodes->length()-1; i++) {
4043     assert(j <= i, "can't write beyond current index");
4044     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
4045       identical++;
4046       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4047       continue;
4048     }
4049     if (identical > 0) {
4050       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4051       identical = 0;
4052     } else {
4053       Node* n = _expensive_nodes->at(i);
4054       igvn.hash_delete(n);
4055       n->set_req(0, NULL);
4056       igvn.hash_insert(n);
4057     }
4058   }
4059   if (identical > 0) {
4060     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4061   } else if (_expensive_nodes->length() >= 1) {
4062     Node* n = _expensive_nodes->at(i);
4063     igvn.hash_delete(n);
4064     n->set_req(0, NULL);
4065     igvn.hash_insert(n);
4066   }
4067   _expensive_nodes->trunc_to(j);
4068 }
4069 
4070 void Compile::add_expensive_node(Node * n) {
4071   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4072   assert(n->is_expensive(), "expensive nodes with non-null control here only");
4073   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4074   if (OptimizeExpensiveOps) {
4075     _expensive_nodes->append(n);
4076   } else {
4077     // Clear control input and let IGVN optimize expensive nodes if
4078     // OptimizeExpensiveOps is off.
4079     n->set_req(0, NULL);
4080   }
4081 }
4082 
4083 /**
4084  * Remove the speculative part of types and clean up the graph
4085  */
4086 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4087   if (UseTypeSpeculation) {
4088     Unique_Node_List worklist;
4089     worklist.push(root());
4090     int modified = 0;
4091     // Go over all type nodes that carry a speculative type, drop the
4092     // speculative part of the type and enqueue the node for an igvn
4093     // which may optimize it out.
4094     for (uint next = 0; next < worklist.size(); ++next) {
4095       Node *n  = worklist.at(next);
4096       if (n->is_Type()) {
4097         TypeNode* tn = n->as_Type();
4098         const Type* t = tn->type();
4099         const Type* t_no_spec = t->remove_speculative();
4100         if (t_no_spec != t) {
4101           bool in_hash = igvn.hash_delete(n);
4102           assert(in_hash, "node should be in igvn hash table");
4103           tn->set_type(t_no_spec);
4104           igvn.hash_insert(n);
4105           igvn._worklist.push(n); // give it a chance to go away
4106           modified++;
4107         }
4108       }
4109       uint max = n->len();
4110       for( uint i = 0; i < max; ++i ) {
4111         Node *m = n->in(i);
4112         if (not_a_node(m))  continue;
4113         worklist.push(m);
4114       }
4115     }
4116     // Drop the speculative part of all types in the igvn's type table
4117     igvn.remove_speculative_types();
4118     if (modified > 0) {
4119       igvn.optimize();
4120     }
4121 #ifdef ASSERT
4122     // Verify that after the IGVN is over no speculative type has resurfaced
4123     worklist.clear();
4124     worklist.push(root());
4125     for (uint next = 0; next < worklist.size(); ++next) {
4126       Node *n  = worklist.at(next);
4127       const Type* t = igvn.type_or_null(n);
4128       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4129       if (n->is_Type()) {
4130         t = n->as_Type()->type();
4131         assert(t == t->remove_speculative(), "no more speculative types");
4132       }
4133       uint max = n->len();
4134       for( uint i = 0; i < max; ++i ) {
4135         Node *m = n->in(i);
4136         if (not_a_node(m))  continue;
4137         worklist.push(m);
4138       }
4139     }
4140     igvn.check_no_speculative_types();
4141 #endif
4142   }
4143 }
4144 
4145 // Auxiliary method to support randomized stressing/fuzzing.
4146 //
4147 // This method can be called the arbitrary number of times, with current count
4148 // as the argument. The logic allows selecting a single candidate from the
4149 // running list of candidates as follows:
4150 //    int count = 0;
4151 //    Cand* selected = null;
4152 //    while(cand = cand->next()) {
4153 //      if (randomized_select(++count)) {
4154 //        selected = cand;
4155 //      }
4156 //    }
4157 //
4158 // Including count equalizes the chances any candidate is "selected".
4159 // This is useful when we don't have the complete list of candidates to choose
4160 // from uniformly. In this case, we need to adjust the randomicity of the
4161 // selection, or else we will end up biasing the selection towards the latter
4162 // candidates.
4163 //
4164 // Quick back-envelope calculation shows that for the list of n candidates
4165 // the equal probability for the candidate to persist as "best" can be
4166 // achieved by replacing it with "next" k-th candidate with the probability
4167 // of 1/k. It can be easily shown that by the end of the run, the
4168 // probability for any candidate is converged to 1/n, thus giving the
4169 // uniform distribution among all the candidates.
4170 //
4171 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4172 #define RANDOMIZED_DOMAIN_POW 29
4173 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4174 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4175 bool Compile::randomized_select(int count) {
4176   assert(count > 0, "only positive");
4177   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4178 }