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/compileBroker.hpp"
  33 #include "compiler/compileLog.hpp"
  34 #include "compiler/disassembler.hpp"
  35 #include "compiler/oopMap.hpp"
  36 #include "opto/addnode.hpp"
  37 #include "opto/block.hpp"
  38 #include "opto/c2compiler.hpp"
  39 #include "opto/callGenerator.hpp"
  40 #include "opto/callnode.hpp"
  41 #include "opto/cfgnode.hpp"
  42 #include "opto/chaitin.hpp"
  43 #include "opto/compile.hpp"
  44 #include "opto/connode.hpp"
  45 #include "opto/divnode.hpp"
  46 #include "opto/escape.hpp"
  47 #include "opto/idealGraphPrinter.hpp"
  48 #include "opto/loopnode.hpp"
  49 #include "opto/machnode.hpp"
  50 #include "opto/macro.hpp"
  51 #include "opto/matcher.hpp"
  52 #include "opto/mathexactnode.hpp"
  53 #include "opto/memnode.hpp"
  54 #include "opto/mulnode.hpp"
  55 #include "opto/narrowptrnode.hpp"
  56 #include "opto/node.hpp"
  57 #include "opto/opcodes.hpp"
  58 #include "opto/output.hpp"
  59 #include "opto/parse.hpp"
  60 #include "opto/phaseX.hpp"
  61 #include "opto/rootnode.hpp"
  62 #include "opto/runtime.hpp"
  63 #include "opto/stringopts.hpp"
  64 #include "opto/type.hpp"
  65 #include "opto/vectornode.hpp"
  66 #include "runtime/arguments.hpp"
  67 #include "runtime/signature.hpp"
  68 #include "runtime/stubRoutines.hpp"
  69 #include "runtime/timer.hpp"
  70 #include "trace/tracing.hpp"
  71 #include "utilities/copy.hpp"
  72 
  73 
  74 // -------------------- Compile::mach_constant_base_node -----------------------
  75 // Constant table base node singleton.
  76 MachConstantBaseNode* Compile::mach_constant_base_node() {
  77   if (_mach_constant_base_node == NULL) {
  78     _mach_constant_base_node = new MachConstantBaseNode();
  79     _mach_constant_base_node->add_req(C->root());
  80   }
  81   return _mach_constant_base_node;
  82 }
  83 
  84 
  85 /// Support for intrinsics.
  86 
  87 // Return the index at which m must be inserted (or already exists).
  88 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
  89 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
  90 #ifdef ASSERT
  91   for (int i = 1; i < _intrinsics->length(); i++) {
  92     CallGenerator* cg1 = _intrinsics->at(i-1);
  93     CallGenerator* cg2 = _intrinsics->at(i);
  94     assert(cg1->method() != cg2->method()
  95            ? cg1->method()     < cg2->method()
  96            : cg1->is_virtual() < cg2->is_virtual(),
  97            "compiler intrinsics list must stay sorted");
  98   }
  99 #endif
 100   // Binary search sorted list, in decreasing intervals [lo, hi].
 101   int lo = 0, hi = _intrinsics->length()-1;
 102   while (lo <= hi) {
 103     int mid = (uint)(hi + lo) / 2;
 104     ciMethod* mid_m = _intrinsics->at(mid)->method();
 105     if (m < mid_m) {
 106       hi = mid-1;
 107     } else if (m > mid_m) {
 108       lo = mid+1;
 109     } else {
 110       // look at minor sort key
 111       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 112       if (is_virtual < mid_virt) {
 113         hi = mid-1;
 114       } else if (is_virtual > mid_virt) {
 115         lo = mid+1;
 116       } else {
 117         return mid;  // exact match
 118       }
 119     }
 120   }
 121   return lo;  // inexact match
 122 }
 123 
 124 void Compile::register_intrinsic(CallGenerator* cg) {
 125   if (_intrinsics == NULL) {
 126     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 127   }
 128   // This code is stolen from ciObjectFactory::insert.
 129   // Really, GrowableArray should have methods for
 130   // insert_at, remove_at, and binary_search.
 131   int len = _intrinsics->length();
 132   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 133   if (index == len) {
 134     _intrinsics->append(cg);
 135   } else {
 136 #ifdef ASSERT
 137     CallGenerator* oldcg = _intrinsics->at(index);
 138     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 139 #endif
 140     _intrinsics->append(_intrinsics->at(len-1));
 141     int pos;
 142     for (pos = len-2; pos >= index; pos--) {
 143       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 144     }
 145     _intrinsics->at_put(index, cg);
 146   }
 147   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 148 }
 149 
 150 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 151   assert(m->is_loaded(), "don't try this on unloaded methods");
 152   if (_intrinsics != NULL) {
 153     int index = intrinsic_insertion_index(m, is_virtual);
 154     if (index < _intrinsics->length()
 155         && _intrinsics->at(index)->method() == m
 156         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 157       return _intrinsics->at(index);
 158     }
 159   }
 160   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 161   if (m->intrinsic_id() != vmIntrinsics::_none &&
 162       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 163     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 164     if (cg != NULL) {
 165       // Save it for next time:
 166       register_intrinsic(cg);
 167       return cg;
 168     } else {
 169       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 170     }
 171   }
 172   return NULL;
 173 }
 174 
 175 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 176 // in library_call.cpp.
 177 
 178 
 179 #ifndef PRODUCT
 180 // statistics gathering...
 181 
 182 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 183 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 184 
 185 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 186   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 187   int oflags = _intrinsic_hist_flags[id];
 188   assert(flags != 0, "what happened?");
 189   if (is_virtual) {
 190     flags |= _intrinsic_virtual;
 191   }
 192   bool changed = (flags != oflags);
 193   if ((flags & _intrinsic_worked) != 0) {
 194     juint count = (_intrinsic_hist_count[id] += 1);
 195     if (count == 1) {
 196       changed = true;           // first time
 197     }
 198     // increment the overall count also:
 199     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 200   }
 201   if (changed) {
 202     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 203       // Something changed about the intrinsic's virtuality.
 204       if ((flags & _intrinsic_virtual) != 0) {
 205         // This is the first use of this intrinsic as a virtual call.
 206         if (oflags != 0) {
 207           // We already saw it as a non-virtual, so note both cases.
 208           flags |= _intrinsic_both;
 209         }
 210       } else if ((oflags & _intrinsic_both) == 0) {
 211         // This is the first use of this intrinsic as a non-virtual
 212         flags |= _intrinsic_both;
 213       }
 214     }
 215     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 216   }
 217   // update the overall flags also:
 218   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 219   return changed;
 220 }
 221 
 222 static char* format_flags(int flags, char* buf) {
 223   buf[0] = 0;
 224   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 225   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 226   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 227   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 228   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 229   if (buf[0] == 0)  strcat(buf, ",");
 230   assert(buf[0] == ',', "must be");
 231   return &buf[1];
 232 }
 233 
 234 void Compile::print_intrinsic_statistics() {
 235   char flagsbuf[100];
 236   ttyLocker ttyl;
 237   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 238   tty->print_cr("Compiler intrinsic usage:");
 239   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 240   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 241   #define PRINT_STAT_LINE(name, c, f) \
 242     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 243   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 244     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 245     int   flags = _intrinsic_hist_flags[id];
 246     juint count = _intrinsic_hist_count[id];
 247     if ((flags | count) != 0) {
 248       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 249     }
 250   }
 251   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 252   if (xtty != NULL)  xtty->tail("statistics");
 253 }
 254 
 255 void Compile::print_statistics() {
 256   { ttyLocker ttyl;
 257     if (xtty != NULL)  xtty->head("statistics type='opto'");
 258     Parse::print_statistics();
 259     PhaseCCP::print_statistics();
 260     PhaseRegAlloc::print_statistics();
 261     Scheduling::print_statistics();
 262     PhasePeephole::print_statistics();
 263     PhaseIdealLoop::print_statistics();
 264     if (xtty != NULL)  xtty->tail("statistics");
 265   }
 266   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 267     // put this under its own <statistics> element.
 268     print_intrinsic_statistics();
 269   }
 270 }
 271 #endif //PRODUCT
 272 
 273 // Support for bundling info
 274 Bundle* Compile::node_bundling(const Node *n) {
 275   assert(valid_bundle_info(n), "oob");
 276   return &_node_bundling_base[n->_idx];
 277 }
 278 
 279 bool Compile::valid_bundle_info(const Node *n) {
 280   return (_node_bundling_limit > n->_idx);
 281 }
 282 
 283 
 284 void Compile::gvn_replace_by(Node* n, Node* nn) {
 285   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 286     Node* use = n->last_out(i);
 287     bool is_in_table = initial_gvn()->hash_delete(use);
 288     uint uses_found = 0;
 289     for (uint j = 0; j < use->len(); j++) {
 290       if (use->in(j) == n) {
 291         if (j < use->req())
 292           use->set_req(j, nn);
 293         else
 294           use->set_prec(j, nn);
 295         uses_found++;
 296       }
 297     }
 298     if (is_in_table) {
 299       // reinsert into table
 300       initial_gvn()->hash_find_insert(use);
 301     }
 302     record_for_igvn(use);
 303     i -= uses_found;    // we deleted 1 or more copies of this edge
 304   }
 305 }
 306 
 307 
 308 static inline bool not_a_node(const Node* n) {
 309   if (n == NULL)                   return true;
 310   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 311   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 312   return false;
 313 }
 314 
 315 // Identify all nodes that are reachable from below, useful.
 316 // Use breadth-first pass that records state in a Unique_Node_List,
 317 // recursive traversal is slower.
 318 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 319   int estimated_worklist_size = unique();
 320   useful.map( estimated_worklist_size, NULL );  // preallocate space
 321 
 322   // Initialize worklist
 323   if (root() != NULL)     { useful.push(root()); }
 324   // If 'top' is cached, declare it useful to preserve cached node
 325   if( cached_top_node() ) { useful.push(cached_top_node()); }
 326 
 327   // Push all useful nodes onto the list, breadthfirst
 328   for( uint next = 0; next < useful.size(); ++next ) {
 329     assert( next < unique(), "Unique useful nodes < total nodes");
 330     Node *n  = useful.at(next);
 331     uint max = n->len();
 332     for( uint i = 0; i < max; ++i ) {
 333       Node *m = n->in(i);
 334       if (not_a_node(m))  continue;
 335       useful.push(m);
 336     }
 337   }
 338 }
 339 
 340 // Update dead_node_list with any missing dead nodes using useful
 341 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 342 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 343   uint max_idx = unique();
 344   VectorSet& useful_node_set = useful.member_set();
 345 
 346   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 347     // If node with index node_idx is not in useful set,
 348     // mark it as dead in dead node list.
 349     if (! useful_node_set.test(node_idx) ) {
 350       record_dead_node(node_idx);
 351     }
 352   }
 353 }
 354 
 355 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 356   int shift = 0;
 357   for (int i = 0; i < inlines->length(); i++) {
 358     CallGenerator* cg = inlines->at(i);
 359     CallNode* call = cg->call_node();
 360     if (shift > 0) {
 361       inlines->at_put(i-shift, cg);
 362     }
 363     if (!useful.member(call)) {
 364       shift++;
 365     }
 366   }
 367   inlines->trunc_to(inlines->length()-shift);
 368 }
 369 
 370 // Disconnect all useless nodes by disconnecting those at the boundary.
 371 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 372   uint next = 0;
 373   while (next < useful.size()) {
 374     Node *n = useful.at(next++);
 375     if (n->is_SafePoint()) {
 376       // We're done with a parsing phase. Replaced nodes are not valid
 377       // beyond that point.
 378       n->as_SafePoint()->delete_replaced_nodes();
 379     }
 380     // Use raw traversal of out edges since this code removes out edges
 381     int max = n->outcnt();
 382     for (int j = 0; j < max; ++j) {
 383       Node* child = n->raw_out(j);
 384       if (! useful.member(child)) {
 385         assert(!child->is_top() || child != top(),
 386                "If top is cached in Compile object it is in useful list");
 387         // Only need to remove this out-edge to the useless node
 388         n->raw_del_out(j);
 389         --j;
 390         --max;
 391       }
 392     }
 393     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 394       record_for_igvn(n->unique_out());
 395     }
 396   }
 397   // Remove useless macro and predicate opaq nodes
 398   for (int i = C->macro_count()-1; i >= 0; i--) {
 399     Node* n = C->macro_node(i);
 400     if (!useful.member(n)) {
 401       remove_macro_node(n);
 402     }
 403   }
 404   // Remove useless expensive node
 405   for (int i = C->expensive_count()-1; i >= 0; i--) {
 406     Node* n = C->expensive_node(i);
 407     if (!useful.member(n)) {
 408       remove_expensive_node(n);
 409     }
 410   }
 411   // clean up the late inline lists
 412   remove_useless_late_inlines(&_string_late_inlines, useful);
 413   remove_useless_late_inlines(&_boxing_late_inlines, useful);
 414   remove_useless_late_inlines(&_late_inlines, useful);
 415   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 416 }
 417 
 418 //------------------------------frame_size_in_words-----------------------------
 419 // frame_slots in units of words
 420 int Compile::frame_size_in_words() const {
 421   // shift is 0 in LP32 and 1 in LP64
 422   const int shift = (LogBytesPerWord - LogBytesPerInt);
 423   int words = _frame_slots >> shift;
 424   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 425   return words;
 426 }
 427 
 428 // To bang the stack of this compiled method we use the stack size
 429 // that the interpreter would need in case of a deoptimization. This
 430 // removes the need to bang the stack in the deoptimization blob which
 431 // in turn simplifies stack overflow handling.
 432 int Compile::bang_size_in_bytes() const {
 433   return MAX2(frame_size_in_bytes() + os::extra_bang_size_in_bytes(), _interpreter_frame_size);
 434 }
 435 
 436 // ============================================================================
 437 //------------------------------CompileWrapper---------------------------------
 438 class CompileWrapper : public StackObj {
 439   Compile *const _compile;
 440  public:
 441   CompileWrapper(Compile* compile);
 442 
 443   ~CompileWrapper();
 444 };
 445 
 446 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 447   // the Compile* pointer is stored in the current ciEnv:
 448   ciEnv* env = compile->env();
 449   assert(env == ciEnv::current(), "must already be a ciEnv active");
 450   assert(env->compiler_data() == NULL, "compile already active?");
 451   env->set_compiler_data(compile);
 452   assert(compile == Compile::current(), "sanity");
 453 
 454   compile->set_type_dict(NULL);
 455   compile->set_type_hwm(NULL);
 456   compile->set_type_last_size(0);
 457   compile->set_last_tf(NULL, NULL);
 458   compile->set_indexSet_arena(NULL);
 459   compile->set_indexSet_free_block_list(NULL);
 460   compile->init_type_arena();
 461   Type::Initialize(compile);
 462   _compile->set_scratch_buffer_blob(NULL);
 463   _compile->begin_method();
 464 }
 465 CompileWrapper::~CompileWrapper() {
 466   _compile->end_method();
 467   if (_compile->scratch_buffer_blob() != NULL)
 468     BufferBlob::free(_compile->scratch_buffer_blob());
 469   _compile->env()->set_compiler_data(NULL);
 470 }
 471 
 472 
 473 //----------------------------print_compile_messages---------------------------
 474 void Compile::print_compile_messages() {
 475 #ifndef PRODUCT
 476   // Check if recompiling
 477   if (_subsume_loads == false && PrintOpto) {
 478     // Recompiling without allowing machine instructions to subsume loads
 479     tty->print_cr("*********************************************************");
 480     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 481     tty->print_cr("*********************************************************");
 482   }
 483   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 484     // Recompiling without escape analysis
 485     tty->print_cr("*********************************************************");
 486     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 487     tty->print_cr("*********************************************************");
 488   }
 489   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 490     // Recompiling without boxing elimination
 491     tty->print_cr("*********************************************************");
 492     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 493     tty->print_cr("*********************************************************");
 494   }
 495   if (env()->break_at_compile()) {
 496     // Open the debugger when compiling this method.
 497     tty->print("### Breaking when compiling: ");
 498     method()->print_short_name();
 499     tty->cr();
 500     BREAKPOINT;
 501   }
 502 
 503   if( PrintOpto ) {
 504     if (is_osr_compilation()) {
 505       tty->print("[OSR]%3d", _compile_id);
 506     } else {
 507       tty->print("%3d", _compile_id);
 508     }
 509   }
 510 #endif
 511 }
 512 
 513 
 514 //-----------------------init_scratch_buffer_blob------------------------------
 515 // Construct a temporary BufferBlob and cache it for this compile.
 516 void Compile::init_scratch_buffer_blob(int const_size) {
 517   // If there is already a scratch buffer blob allocated and the
 518   // constant section is big enough, use it.  Otherwise free the
 519   // current and allocate a new one.
 520   BufferBlob* blob = scratch_buffer_blob();
 521   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 522     // Use the current blob.
 523   } else {
 524     if (blob != NULL) {
 525       BufferBlob::free(blob);
 526     }
 527 
 528     ResourceMark rm;
 529     _scratch_const_size = const_size;
 530     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 531     blob = BufferBlob::create("Compile::scratch_buffer", size);
 532     // Record the buffer blob for next time.
 533     set_scratch_buffer_blob(blob);
 534     // Have we run out of code space?
 535     if (scratch_buffer_blob() == NULL) {
 536       // Let CompilerBroker disable further compilations.
 537       record_failure("Not enough space for scratch buffer in CodeCache");
 538       CompileBroker::handle_full_code_cache();
 539       return;
 540     }
 541   }
 542 
 543   // Initialize the relocation buffers
 544   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 545   set_scratch_locs_memory(locs_buf);
 546 }
 547 
 548 
 549 //-----------------------scratch_emit_size-------------------------------------
 550 // Helper function that computes size by emitting code
 551 uint Compile::scratch_emit_size(const Node* n) {
 552   // Start scratch_emit_size section.
 553   set_in_scratch_emit_size(true);
 554 
 555   // Emit into a trash buffer and count bytes emitted.
 556   // This is a pretty expensive way to compute a size,
 557   // but it works well enough if seldom used.
 558   // All common fixed-size instructions are given a size
 559   // method by the AD file.
 560   // Note that the scratch buffer blob and locs memory are
 561   // allocated at the beginning of the compile task, and
 562   // may be shared by several calls to scratch_emit_size.
 563   // The allocation of the scratch buffer blob is particularly
 564   // expensive, since it has to grab the code cache lock.
 565   BufferBlob* blob = this->scratch_buffer_blob();
 566   assert(blob != NULL, "Initialize BufferBlob at start");
 567   assert(blob->size() > MAX_inst_size, "sanity");
 568   relocInfo* locs_buf = scratch_locs_memory();
 569   address blob_begin = blob->content_begin();
 570   address blob_end   = (address)locs_buf;
 571   assert(blob->content_contains(blob_end), "sanity");
 572   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 573   buf.initialize_consts_size(_scratch_const_size);
 574   buf.initialize_stubs_size(MAX_stubs_size);
 575   assert(locs_buf != NULL, "sanity");
 576   int lsize = MAX_locs_size / 3;
 577   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 578   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 579   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 580 
 581   // Do the emission.
 582 
 583   Label fakeL; // Fake label for branch instructions.
 584   Label*   saveL = NULL;
 585   uint save_bnum = 0;
 586   bool is_branch = n->is_MachBranch();
 587   if (is_branch) {
 588     MacroAssembler masm(&buf);
 589     masm.bind(fakeL);
 590     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 591     n->as_MachBranch()->label_set(&fakeL, 0);
 592   }
 593   n->emit(buf, this->regalloc());
 594   if (is_branch) // Restore label.
 595     n->as_MachBranch()->label_set(saveL, save_bnum);
 596 
 597   // End scratch_emit_size section.
 598   set_in_scratch_emit_size(false);
 599 
 600   return buf.insts_size();
 601 }
 602 
 603 
 604 // ============================================================================
 605 //------------------------------Compile standard-------------------------------
 606 debug_only( int Compile::_debug_idx = 100000; )
 607 
 608 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 609 // the continuation bci for on stack replacement.
 610 
 611 
 612 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 613                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
 614                 : Phase(Compiler),
 615                   _env(ci_env),
 616                   _log(ci_env->log()),
 617                   _compile_id(ci_env->compile_id()),
 618                   _save_argument_registers(false),
 619                   _stub_name(NULL),
 620                   _stub_function(NULL),
 621                   _stub_entry_point(NULL),
 622                   _method(target),
 623                   _entry_bci(osr_bci),
 624                   _initial_gvn(NULL),
 625                   _for_igvn(NULL),
 626                   _warm_calls(NULL),
 627                   _subsume_loads(subsume_loads),
 628                   _do_escape_analysis(do_escape_analysis),
 629                   _eliminate_boxing(eliminate_boxing),
 630                   _failure_reason(NULL),
 631                   _code_buffer("Compile::Fill_buffer"),
 632                   _orig_pc_slot(0),
 633                   _orig_pc_slot_offset_in_bytes(0),
 634                   _has_method_handle_invokes(false),
 635                   _mach_constant_base_node(NULL),
 636                   _node_bundling_limit(0),
 637                   _node_bundling_base(NULL),
 638                   _java_calls(0),
 639                   _inner_loops(0),
 640                   _scratch_const_size(-1),
 641                   _in_scratch_emit_size(false),
 642                   _dead_node_list(comp_arena()),
 643                   _dead_node_count(0),
 644 #ifndef PRODUCT
 645                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 646                   _in_dump_cnt(0),
 647                   _printer(IdealGraphPrinter::printer()),
 648 #endif
 649                   _congraph(NULL),
 650                   _comp_arena(mtCompiler),
 651                   _node_arena(mtCompiler),
 652                   _old_arena(mtCompiler),
 653                   _Compile_types(mtCompiler),
 654                   _replay_inline_data(NULL),
 655                   _late_inlines(comp_arena(), 2, 0, NULL),
 656                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 657                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 658                   _late_inlines_pos(0),
 659                   _number_of_mh_late_inlines(0),
 660                   _inlining_progress(false),
 661                   _inlining_incrementally(false),
 662                   _print_inlining_list(NULL),
 663                   _print_inlining_stream(NULL),
 664                   _print_inlining_idx(0),
 665                   _print_inlining_output(NULL),
 666                   _interpreter_frame_size(0) {
 667   C = this;
 668 
 669   CompileWrapper cw(this);
 670 #ifndef PRODUCT
 671   if (TimeCompiler2) {
 672     tty->print(" ");
 673     target->holder()->name()->print();
 674     tty->print(".");
 675     target->print_short_name();
 676     tty->print("  ");
 677   }
 678   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 679   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 680   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 681   if (!print_opto_assembly) {
 682     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 683     if (print_assembly && !Disassembler::can_decode()) {
 684       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 685       print_opto_assembly = true;
 686     }
 687   }
 688   set_print_assembly(print_opto_assembly);
 689   set_parsed_irreducible_loop(false);
 690 
 691   if (method()->has_option("ReplayInline")) {
 692     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 693   }
 694 #endif
 695   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
 696   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
 697   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 698 
 699   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 700     // Make sure the method being compiled gets its own MDO,
 701     // so we can at least track the decompile_count().
 702     // Need MDO to record RTM code generation state.
 703     method()->ensure_method_data();
 704   }
 705 
 706   Init(::AliasLevel);
 707 
 708 
 709   print_compile_messages();
 710 
 711   _ilt = InlineTree::build_inline_tree_root();
 712 
 713   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 714   assert(num_alias_types() >= AliasIdxRaw, "");
 715 
 716 #define MINIMUM_NODE_HASH  1023
 717   // Node list that Iterative GVN will start with
 718   Unique_Node_List for_igvn(comp_arena());
 719   set_for_igvn(&for_igvn);
 720 
 721   // GVN that will be run immediately on new nodes
 722   uint estimated_size = method()->code_size()*4+64;
 723   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 724   PhaseGVN gvn(node_arena(), estimated_size);
 725   set_initial_gvn(&gvn);
 726 
 727   print_inlining_init();
 728   { // Scope for timing the parser
 729     TracePhase t3("parse", &_t_parser, true);
 730 
 731     // Put top into the hash table ASAP.
 732     initial_gvn()->transform_no_reclaim(top());
 733 
 734     // Set up tf(), start(), and find a CallGenerator.
 735     CallGenerator* cg = NULL;
 736     if (is_osr_compilation()) {
 737       const TypeTuple *domain = StartOSRNode::osr_domain();
 738       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 739       init_tf(TypeFunc::make(domain, range));
 740       StartNode* s = new StartOSRNode(root(), domain);
 741       initial_gvn()->set_type_bottom(s);
 742       init_start(s);
 743       cg = CallGenerator::for_osr(method(), entry_bci());
 744     } else {
 745       // Normal case.
 746       init_tf(TypeFunc::make(method()));
 747       StartNode* s = new StartNode(root(), tf()->domain());
 748       initial_gvn()->set_type_bottom(s);
 749       init_start(s);
 750       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 751         // With java.lang.ref.reference.get() we must go through the
 752         // intrinsic when G1 is enabled - even when get() is the root
 753         // method of the compile - so that, if necessary, the value in
 754         // the referent field of the reference object gets recorded by
 755         // the pre-barrier code.
 756         // Specifically, if G1 is enabled, the value in the referent
 757         // field is recorded by the G1 SATB pre barrier. This will
 758         // result in the referent being marked live and the reference
 759         // object removed from the list of discovered references during
 760         // reference processing.
 761         cg = find_intrinsic(method(), false);
 762       }
 763       if (cg == NULL) {
 764         float past_uses = method()->interpreter_invocation_count();
 765         float expected_uses = past_uses;
 766         cg = CallGenerator::for_inline(method(), expected_uses);
 767       }
 768     }
 769     if (failing())  return;
 770     if (cg == NULL) {
 771       record_method_not_compilable_all_tiers("cannot parse method");
 772       return;
 773     }
 774     JVMState* jvms = build_start_state(start(), tf());
 775     if ((jvms = cg->generate(jvms)) == NULL) {
 776       record_method_not_compilable("method parse failed");
 777       return;
 778     }
 779     GraphKit kit(jvms);
 780 
 781     if (!kit.stopped()) {
 782       // Accept return values, and transfer control we know not where.
 783       // This is done by a special, unique ReturnNode bound to root.
 784       return_values(kit.jvms());
 785     }
 786 
 787     if (kit.has_exceptions()) {
 788       // Any exceptions that escape from this call must be rethrown
 789       // to whatever caller is dynamically above us on the stack.
 790       // This is done by a special, unique RethrowNode bound to root.
 791       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 792     }
 793 
 794     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 795 
 796     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 797       inline_string_calls(true);
 798     }
 799 
 800     if (failing())  return;
 801 
 802     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 803 
 804     // Remove clutter produced by parsing.
 805     if (!failing()) {
 806       ResourceMark rm;
 807       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 808     }
 809   }
 810 
 811   // Note:  Large methods are capped off in do_one_bytecode().
 812   if (failing())  return;
 813 
 814   // After parsing, node notes are no longer automagic.
 815   // They must be propagated by register_new_node_with_optimizer(),
 816   // clone(), or the like.
 817   set_default_node_notes(NULL);
 818 
 819   for (;;) {
 820     int successes = Inline_Warm();
 821     if (failing())  return;
 822     if (successes == 0)  break;
 823   }
 824 
 825   // Drain the list.
 826   Finish_Warm();
 827 #ifndef PRODUCT
 828   if (_printer) {
 829     _printer->print_inlining(this);
 830   }
 831 #endif
 832 
 833   if (failing())  return;
 834   NOT_PRODUCT( verify_graph_edges(); )
 835 
 836   // Now optimize
 837   Optimize();
 838   if (failing())  return;
 839   NOT_PRODUCT( verify_graph_edges(); )
 840 
 841 #ifndef PRODUCT
 842   if (PrintIdeal) {
 843     ttyLocker ttyl;  // keep the following output all in one block
 844     // This output goes directly to the tty, not the compiler log.
 845     // To enable tools to match it up with the compilation activity,
 846     // be sure to tag this tty output with the compile ID.
 847     if (xtty != NULL) {
 848       xtty->head("ideal compile_id='%d'%s", compile_id(),
 849                  is_osr_compilation()    ? " compile_kind='osr'" :
 850                  "");
 851     }
 852     root()->dump(9999);
 853     if (xtty != NULL) {
 854       xtty->tail("ideal");
 855     }
 856   }
 857 #endif
 858 
 859   NOT_PRODUCT( verify_barriers(); )
 860 
 861   // Dump compilation data to replay it.
 862   if (method()->has_option("DumpReplay")) {
 863     env()->dump_replay_data(_compile_id);
 864   }
 865   if (method()->has_option("DumpInline") && (ilt() != NULL)) {
 866     env()->dump_inline_data(_compile_id);
 867   }
 868 
 869   // Now that we know the size of all the monitors we can add a fixed slot
 870   // for the original deopt pc.
 871 
 872   _orig_pc_slot =  fixed_slots();
 873   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 874   set_fixed_slots(next_slot);
 875 
 876   // Compute when to use implicit null checks. Used by matching trap based
 877   // nodes and NullCheck optimization.
 878   set_allowed_deopt_reasons();
 879 
 880   // Now generate code
 881   Code_Gen();
 882   if (failing())  return;
 883 
 884   // Check if we want to skip execution of all compiled code.
 885   {
 886 #ifndef PRODUCT
 887     if (OptoNoExecute) {
 888       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 889       return;
 890     }
 891     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 892 #endif
 893 
 894     if (is_osr_compilation()) {
 895       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 896       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 897     } else {
 898       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 899       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 900     }
 901 
 902     env()->register_method(_method, _entry_bci,
 903                            &_code_offsets,
 904                            _orig_pc_slot_offset_in_bytes,
 905                            code_buffer(),
 906                            frame_size_in_words(), _oop_map_set,
 907                            &_handler_table, &_inc_table,
 908                            compiler,
 909                            env()->comp_level(),
 910                            has_unsafe_access(),
 911                            SharedRuntime::is_wide_vector(max_vector_size()),
 912                            rtm_state()
 913                            );
 914 
 915     if (log() != NULL) // Print code cache state into compiler log
 916       log()->code_cache_state();
 917   }
 918 }
 919 
 920 //------------------------------Compile----------------------------------------
 921 // Compile a runtime stub
 922 Compile::Compile( ciEnv* ci_env,
 923                   TypeFunc_generator generator,
 924                   address stub_function,
 925                   const char *stub_name,
 926                   int is_fancy_jump,
 927                   bool pass_tls,
 928                   bool save_arg_registers,
 929                   bool return_pc )
 930   : Phase(Compiler),
 931     _env(ci_env),
 932     _log(ci_env->log()),
 933     _compile_id(0),
 934     _save_argument_registers(save_arg_registers),
 935     _method(NULL),
 936     _stub_name(stub_name),
 937     _stub_function(stub_function),
 938     _stub_entry_point(NULL),
 939     _entry_bci(InvocationEntryBci),
 940     _initial_gvn(NULL),
 941     _for_igvn(NULL),
 942     _warm_calls(NULL),
 943     _orig_pc_slot(0),
 944     _orig_pc_slot_offset_in_bytes(0),
 945     _subsume_loads(true),
 946     _do_escape_analysis(false),
 947     _eliminate_boxing(false),
 948     _failure_reason(NULL),
 949     _code_buffer("Compile::Fill_buffer"),
 950     _has_method_handle_invokes(false),
 951     _mach_constant_base_node(NULL),
 952     _node_bundling_limit(0),
 953     _node_bundling_base(NULL),
 954     _java_calls(0),
 955     _inner_loops(0),
 956 #ifndef PRODUCT
 957     _trace_opto_output(TraceOptoOutput),
 958     _in_dump_cnt(0),
 959     _printer(NULL),
 960 #endif
 961     _comp_arena(mtCompiler),
 962     _node_arena(mtCompiler),
 963     _old_arena(mtCompiler),
 964     _Compile_types(mtCompiler),
 965     _dead_node_list(comp_arena()),
 966     _dead_node_count(0),
 967     _congraph(NULL),
 968     _replay_inline_data(NULL),
 969     _number_of_mh_late_inlines(0),
 970     _inlining_progress(false),
 971     _inlining_incrementally(false),
 972     _print_inlining_list(NULL),
 973     _print_inlining_stream(NULL),
 974     _print_inlining_idx(0),
 975     _print_inlining_output(NULL),
 976     _allowed_reasons(0),
 977     _interpreter_frame_size(0) {
 978   C = this;
 979 
 980 #ifndef PRODUCT
 981   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 982   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
 983   set_print_assembly(PrintFrameConverterAssembly);
 984   set_parsed_irreducible_loop(false);
 985 #endif
 986   set_has_irreducible_loop(false); // no loops
 987 
 988   CompileWrapper cw(this);
 989   Init(/*AliasLevel=*/ 0);
 990   init_tf((*generator)());
 991 
 992   {
 993     // The following is a dummy for the sake of GraphKit::gen_stub
 994     Unique_Node_List for_igvn(comp_arena());
 995     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
 996     PhaseGVN gvn(Thread::current()->resource_area(),255);
 997     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
 998     gvn.transform_no_reclaim(top());
 999 
1000     GraphKit kit;
1001     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1002   }
1003 
1004   NOT_PRODUCT( verify_graph_edges(); )
1005   Code_Gen();
1006   if (failing())  return;
1007 
1008 
1009   // Entry point will be accessed using compile->stub_entry_point();
1010   if (code_buffer() == NULL) {
1011     Matcher::soft_match_failure();
1012   } else {
1013     if (PrintAssembly && (WizardMode || Verbose))
1014       tty->print_cr("### Stub::%s", stub_name);
1015 
1016     if (!failing()) {
1017       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1018 
1019       // Make the NMethod
1020       // For now we mark the frame as never safe for profile stackwalking
1021       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1022                                                       code_buffer(),
1023                                                       CodeOffsets::frame_never_safe,
1024                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1025                                                       frame_size_in_words(),
1026                                                       _oop_map_set,
1027                                                       save_arg_registers);
1028       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1029 
1030       _stub_entry_point = rs->entry_point();
1031     }
1032   }
1033 }
1034 
1035 //------------------------------Init-------------------------------------------
1036 // Prepare for a single compilation
1037 void Compile::Init(int aliaslevel) {
1038   _unique  = 0;
1039   _regalloc = NULL;
1040 
1041   _tf      = NULL;  // filled in later
1042   _top     = NULL;  // cached later
1043   _matcher = NULL;  // filled in later
1044   _cfg     = NULL;  // filled in later
1045 
1046   set_24_bit_selection_and_mode(Use24BitFP, false);
1047 
1048   _node_note_array = NULL;
1049   _default_node_notes = NULL;
1050   DEBUG_ONLY( _modified_nodes = NULL; ) // Used in Optimize()
1051 
1052   _immutable_memory = NULL; // filled in at first inquiry
1053 
1054   // Globally visible Nodes
1055   // First set TOP to NULL to give safe behavior during creation of RootNode
1056   set_cached_top_node(NULL);
1057   set_root(new RootNode());
1058   // Now that you have a Root to point to, create the real TOP
1059   set_cached_top_node( new ConNode(Type::TOP) );
1060   set_recent_alloc(NULL, NULL);
1061 
1062   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1063   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1064   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1065   env()->set_dependencies(new Dependencies(env()));
1066 
1067   _fixed_slots = 0;
1068   set_has_split_ifs(false);
1069   set_has_loops(has_method() && method()->has_loops()); // first approximation
1070   set_has_stringbuilder(false);
1071   set_has_boxed_value(false);
1072   _trap_can_recompile = false;  // no traps emitted yet
1073   _major_progress = true; // start out assuming good things will happen
1074   set_has_unsafe_access(false);
1075   set_max_vector_size(0);
1076   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1077   set_decompile_count(0);
1078 
1079   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1080   set_num_loop_opts(LoopOptsCount);
1081   set_do_inlining(Inline);
1082   set_max_inline_size(MaxInlineSize);
1083   set_freq_inline_size(FreqInlineSize);
1084   set_do_scheduling(OptoScheduling);
1085   set_do_count_invocations(false);
1086   set_do_method_data_update(false);
1087   set_age_code(has_method() && method()->profile_aging());
1088   set_rtm_state(NoRTM); // No RTM lock eliding by default
1089 #if INCLUDE_RTM_OPT
1090   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1091     int rtm_state = method()->method_data()->rtm_state();
1092     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1093       // Don't generate RTM lock eliding code.
1094       set_rtm_state(NoRTM);
1095     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1096       // Generate RTM lock eliding code without abort ratio calculation code.
1097       set_rtm_state(UseRTM);
1098     } else if (UseRTMDeopt) {
1099       // Generate RTM lock eliding code and include abort ratio calculation
1100       // code if UseRTMDeopt is on.
1101       set_rtm_state(ProfileRTM);
1102     }
1103   }
1104 #endif
1105   if (debug_info()->recording_non_safepoints()) {
1106     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1107                         (comp_arena(), 8, 0, NULL));
1108     set_default_node_notes(Node_Notes::make(this));
1109   }
1110 
1111   // // -- Initialize types before each compile --
1112   // // Update cached type information
1113   // if( _method && _method->constants() )
1114   //   Type::update_loaded_types(_method, _method->constants());
1115 
1116   // Init alias_type map.
1117   if (!_do_escape_analysis && aliaslevel == 3)
1118     aliaslevel = 2;  // No unique types without escape analysis
1119   _AliasLevel = aliaslevel;
1120   const int grow_ats = 16;
1121   _max_alias_types = grow_ats;
1122   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1123   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1124   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1125   {
1126     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1127   }
1128   // Initialize the first few types.
1129   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1130   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1131   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1132   _num_alias_types = AliasIdxRaw+1;
1133   // Zero out the alias type cache.
1134   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1135   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1136   probe_alias_cache(NULL)->_index = AliasIdxTop;
1137 
1138   _intrinsics = NULL;
1139   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1140   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1141   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1142   register_library_intrinsics();
1143 }
1144 
1145 //---------------------------init_start----------------------------------------
1146 // Install the StartNode on this compile object.
1147 void Compile::init_start(StartNode* s) {
1148   if (failing())
1149     return; // already failing
1150   assert(s == start(), "");
1151 }
1152 
1153 StartNode* Compile::start() const {
1154   assert(!failing(), "");
1155   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1156     Node* start = root()->fast_out(i);
1157     if( start->is_Start() )
1158       return start->as_Start();
1159   }
1160   fatal("Did not find Start node!");
1161   return NULL;
1162 }
1163 
1164 //-------------------------------immutable_memory-------------------------------------
1165 // Access immutable memory
1166 Node* Compile::immutable_memory() {
1167   if (_immutable_memory != NULL) {
1168     return _immutable_memory;
1169   }
1170   StartNode* s = start();
1171   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1172     Node *p = s->fast_out(i);
1173     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1174       _immutable_memory = p;
1175       return _immutable_memory;
1176     }
1177   }
1178   ShouldNotReachHere();
1179   return NULL;
1180 }
1181 
1182 //----------------------set_cached_top_node------------------------------------
1183 // Install the cached top node, and make sure Node::is_top works correctly.
1184 void Compile::set_cached_top_node(Node* tn) {
1185   if (tn != NULL)  verify_top(tn);
1186   Node* old_top = _top;
1187   _top = tn;
1188   // Calling Node::setup_is_top allows the nodes the chance to adjust
1189   // their _out arrays.
1190   if (_top != NULL)     _top->setup_is_top();
1191   if (old_top != NULL)  old_top->setup_is_top();
1192   assert(_top == NULL || top()->is_top(), "");
1193 }
1194 
1195 #ifdef ASSERT
1196 uint Compile::count_live_nodes_by_graph_walk() {
1197   Unique_Node_List useful(comp_arena());
1198   // Get useful node list by walking the graph.
1199   identify_useful_nodes(useful);
1200   return useful.size();
1201 }
1202 
1203 void Compile::print_missing_nodes() {
1204 
1205   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1206   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1207     return;
1208   }
1209 
1210   // This is an expensive function. It is executed only when the user
1211   // specifies VerifyIdealNodeCount option or otherwise knows the
1212   // additional work that needs to be done to identify reachable nodes
1213   // by walking the flow graph and find the missing ones using
1214   // _dead_node_list.
1215 
1216   Unique_Node_List useful(comp_arena());
1217   // Get useful node list by walking the graph.
1218   identify_useful_nodes(useful);
1219 
1220   uint l_nodes = C->live_nodes();
1221   uint l_nodes_by_walk = useful.size();
1222 
1223   if (l_nodes != l_nodes_by_walk) {
1224     if (_log != NULL) {
1225       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1226       _log->stamp();
1227       _log->end_head();
1228     }
1229     VectorSet& useful_member_set = useful.member_set();
1230     int last_idx = l_nodes_by_walk;
1231     for (int i = 0; i < last_idx; i++) {
1232       if (useful_member_set.test(i)) {
1233         if (_dead_node_list.test(i)) {
1234           if (_log != NULL) {
1235             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1236           }
1237           if (PrintIdealNodeCount) {
1238             // Print the log message to tty
1239               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1240               useful.at(i)->dump();
1241           }
1242         }
1243       }
1244       else if (! _dead_node_list.test(i)) {
1245         if (_log != NULL) {
1246           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1247         }
1248         if (PrintIdealNodeCount) {
1249           // Print the log message to tty
1250           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1251         }
1252       }
1253     }
1254     if (_log != NULL) {
1255       _log->tail("mismatched_nodes");
1256     }
1257   }
1258 }
1259 void Compile::record_modified_node(Node* n) {
1260   if (_modified_nodes != NULL && !_inlining_incrementally &&
1261       n->outcnt() != 0 && !n->is_Con()) {
1262     _modified_nodes->push(n);
1263   }
1264 }
1265 
1266 void Compile::remove_modified_node(Node* n) {
1267   if (_modified_nodes != NULL) {
1268     _modified_nodes->remove(n);
1269   }
1270 }
1271 #endif
1272 
1273 #ifndef PRODUCT
1274 void Compile::verify_top(Node* tn) const {
1275   if (tn != NULL) {
1276     assert(tn->is_Con(), "top node must be a constant");
1277     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1278     assert(tn->in(0) != NULL, "must have live top node");
1279   }
1280 }
1281 #endif
1282 
1283 
1284 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1285 
1286 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1287   guarantee(arr != NULL, "");
1288   int num_blocks = arr->length();
1289   if (grow_by < num_blocks)  grow_by = num_blocks;
1290   int num_notes = grow_by * _node_notes_block_size;
1291   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1292   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1293   while (num_notes > 0) {
1294     arr->append(notes);
1295     notes     += _node_notes_block_size;
1296     num_notes -= _node_notes_block_size;
1297   }
1298   assert(num_notes == 0, "exact multiple, please");
1299 }
1300 
1301 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1302   if (source == NULL || dest == NULL)  return false;
1303 
1304   if (dest->is_Con())
1305     return false;               // Do not push debug info onto constants.
1306 
1307 #ifdef ASSERT
1308   // Leave a bread crumb trail pointing to the original node:
1309   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1310     dest->set_debug_orig(source);
1311   }
1312 #endif
1313 
1314   if (node_note_array() == NULL)
1315     return false;               // Not collecting any notes now.
1316 
1317   // This is a copy onto a pre-existing node, which may already have notes.
1318   // If both nodes have notes, do not overwrite any pre-existing notes.
1319   Node_Notes* source_notes = node_notes_at(source->_idx);
1320   if (source_notes == NULL || source_notes->is_clear())  return false;
1321   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1322   if (dest_notes == NULL || dest_notes->is_clear()) {
1323     return set_node_notes_at(dest->_idx, source_notes);
1324   }
1325 
1326   Node_Notes merged_notes = (*source_notes);
1327   // The order of operations here ensures that dest notes will win...
1328   merged_notes.update_from(dest_notes);
1329   return set_node_notes_at(dest->_idx, &merged_notes);
1330 }
1331 
1332 
1333 //--------------------------allow_range_check_smearing-------------------------
1334 // Gating condition for coalescing similar range checks.
1335 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1336 // single covering check that is at least as strong as any of them.
1337 // If the optimization succeeds, the simplified (strengthened) range check
1338 // will always succeed.  If it fails, we will deopt, and then give up
1339 // on the optimization.
1340 bool Compile::allow_range_check_smearing() const {
1341   // If this method has already thrown a range-check,
1342   // assume it was because we already tried range smearing
1343   // and it failed.
1344   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1345   return !already_trapped;
1346 }
1347 
1348 
1349 //------------------------------flatten_alias_type-----------------------------
1350 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1351   int offset = tj->offset();
1352   TypePtr::PTR ptr = tj->ptr();
1353 
1354   // Known instance (scalarizable allocation) alias only with itself.
1355   bool is_known_inst = tj->isa_oopptr() != NULL &&
1356                        tj->is_oopptr()->is_known_instance();
1357 
1358   // Process weird unsafe references.
1359   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1360     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1361     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1362     tj = TypeOopPtr::BOTTOM;
1363     ptr = tj->ptr();
1364     offset = tj->offset();
1365   }
1366 
1367   // Array pointers need some flattening
1368   const TypeAryPtr *ta = tj->isa_aryptr();
1369   if (ta && ta->is_stable()) {
1370     // Erase stability property for alias analysis.
1371     tj = ta = ta->cast_to_stable(false);
1372   }
1373   if( ta && is_known_inst ) {
1374     if ( offset != Type::OffsetBot &&
1375          offset > arrayOopDesc::length_offset_in_bytes() ) {
1376       offset = Type::OffsetBot; // Flatten constant access into array body only
1377       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1378     }
1379   } else if( ta && _AliasLevel >= 2 ) {
1380     // For arrays indexed by constant indices, we flatten the alias
1381     // space to include all of the array body.  Only the header, klass
1382     // and array length can be accessed un-aliased.
1383     if( offset != Type::OffsetBot ) {
1384       if( ta->const_oop() ) { // MethodData* or Method*
1385         offset = Type::OffsetBot;   // Flatten constant access into array body
1386         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1387       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1388         // range is OK as-is.
1389         tj = ta = TypeAryPtr::RANGE;
1390       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1391         tj = TypeInstPtr::KLASS; // all klass loads look alike
1392         ta = TypeAryPtr::RANGE; // generic ignored junk
1393         ptr = TypePtr::BotPTR;
1394       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1395         tj = TypeInstPtr::MARK;
1396         ta = TypeAryPtr::RANGE; // generic ignored junk
1397         ptr = TypePtr::BotPTR;
1398       } else {                  // Random constant offset into array body
1399         offset = Type::OffsetBot;   // Flatten constant access into array body
1400         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1401       }
1402     }
1403     // Arrays of fixed size alias with arrays of unknown size.
1404     if (ta->size() != TypeInt::POS) {
1405       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1406       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1407     }
1408     // Arrays of known objects become arrays of unknown objects.
1409     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1410       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1411       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1412     }
1413     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1414       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1415       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1416     }
1417     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1418     // cannot be distinguished by bytecode alone.
1419     if (ta->elem() == TypeInt::BOOL) {
1420       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1421       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1422       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1423     }
1424     // During the 2nd round of IterGVN, NotNull castings are removed.
1425     // Make sure the Bottom and NotNull variants alias the same.
1426     // Also, make sure exact and non-exact variants alias the same.
1427     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1428       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1429     }
1430   }
1431 
1432   // Oop pointers need some flattening
1433   const TypeInstPtr *to = tj->isa_instptr();
1434   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1435     ciInstanceKlass *k = to->klass()->as_instance_klass();
1436     if( ptr == TypePtr::Constant ) {
1437       if (to->klass() != ciEnv::current()->Class_klass() ||
1438           offset < k->size_helper() * wordSize) {
1439         // No constant oop pointers (such as Strings); they alias with
1440         // unknown strings.
1441         assert(!is_known_inst, "not scalarizable allocation");
1442         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1443       }
1444     } else if( is_known_inst ) {
1445       tj = to; // Keep NotNull and klass_is_exact for instance type
1446     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1447       // During the 2nd round of IterGVN, NotNull castings are removed.
1448       // Make sure the Bottom and NotNull variants alias the same.
1449       // Also, make sure exact and non-exact variants alias the same.
1450       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1451     }
1452     if (to->speculative() != NULL) {
1453       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1454     }
1455     // Canonicalize the holder of this field
1456     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1457       // First handle header references such as a LoadKlassNode, even if the
1458       // object's klass is unloaded at compile time (4965979).
1459       if (!is_known_inst) { // Do it only for non-instance types
1460         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1461       }
1462     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1463       // Static fields are in the space above the normal instance
1464       // fields in the java.lang.Class instance.
1465       if (to->klass() != ciEnv::current()->Class_klass()) {
1466         to = NULL;
1467         tj = TypeOopPtr::BOTTOM;
1468         offset = tj->offset();
1469       }
1470     } else {
1471       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1472       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1473         if( is_known_inst ) {
1474           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1475         } else {
1476           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1477         }
1478       }
1479     }
1480   }
1481 
1482   // Klass pointers to object array klasses need some flattening
1483   const TypeKlassPtr *tk = tj->isa_klassptr();
1484   if( tk ) {
1485     // If we are referencing a field within a Klass, we need
1486     // to assume the worst case of an Object.  Both exact and
1487     // inexact types must flatten to the same alias class so
1488     // use NotNull as the PTR.
1489     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1490 
1491       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1492                                    TypeKlassPtr::OBJECT->klass(),
1493                                    offset);
1494     }
1495 
1496     ciKlass* klass = tk->klass();
1497     if( klass->is_obj_array_klass() ) {
1498       ciKlass* k = TypeAryPtr::OOPS->klass();
1499       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1500         k = TypeInstPtr::BOTTOM->klass();
1501       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1502     }
1503 
1504     // Check for precise loads from the primary supertype array and force them
1505     // to the supertype cache alias index.  Check for generic array loads from
1506     // the primary supertype array and also force them to the supertype cache
1507     // alias index.  Since the same load can reach both, we need to merge
1508     // these 2 disparate memories into the same alias class.  Since the
1509     // primary supertype array is read-only, there's no chance of confusion
1510     // where we bypass an array load and an array store.
1511     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1512     if (offset == Type::OffsetBot ||
1513         (offset >= primary_supers_offset &&
1514          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1515         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1516       offset = in_bytes(Klass::secondary_super_cache_offset());
1517       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1518     }
1519   }
1520 
1521   // Flatten all Raw pointers together.
1522   if (tj->base() == Type::RawPtr)
1523     tj = TypeRawPtr::BOTTOM;
1524 
1525   if (tj->base() == Type::AnyPtr)
1526     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1527 
1528   // Flatten all to bottom for now
1529   switch( _AliasLevel ) {
1530   case 0:
1531     tj = TypePtr::BOTTOM;
1532     break;
1533   case 1:                       // Flatten to: oop, static, field or array
1534     switch (tj->base()) {
1535     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1536     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1537     case Type::AryPtr:   // do not distinguish arrays at all
1538     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1539     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1540     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1541     default: ShouldNotReachHere();
1542     }
1543     break;
1544   case 2:                       // No collapsing at level 2; keep all splits
1545   case 3:                       // No collapsing at level 3; keep all splits
1546     break;
1547   default:
1548     Unimplemented();
1549   }
1550 
1551   offset = tj->offset();
1552   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1553 
1554   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1555           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1556           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1557           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1558           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1559           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1560           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1561           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1562   assert( tj->ptr() != TypePtr::TopPTR &&
1563           tj->ptr() != TypePtr::AnyNull &&
1564           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1565 //    assert( tj->ptr() != TypePtr::Constant ||
1566 //            tj->base() == Type::RawPtr ||
1567 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1568 
1569   return tj;
1570 }
1571 
1572 void Compile::AliasType::Init(int i, const TypePtr* at) {
1573   _index = i;
1574   _adr_type = at;
1575   _field = NULL;
1576   _element = NULL;
1577   _is_rewritable = true; // default
1578   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1579   if (atoop != NULL && atoop->is_known_instance()) {
1580     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1581     _general_index = Compile::current()->get_alias_index(gt);
1582   } else {
1583     _general_index = 0;
1584   }
1585 }
1586 
1587 //---------------------------------print_on------------------------------------
1588 #ifndef PRODUCT
1589 void Compile::AliasType::print_on(outputStream* st) {
1590   if (index() < 10)
1591         st->print("@ <%d> ", index());
1592   else  st->print("@ <%d>",  index());
1593   st->print(is_rewritable() ? "   " : " RO");
1594   int offset = adr_type()->offset();
1595   if (offset == Type::OffsetBot)
1596         st->print(" +any");
1597   else  st->print(" +%-3d", offset);
1598   st->print(" in ");
1599   adr_type()->dump_on(st);
1600   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1601   if (field() != NULL && tjp) {
1602     if (tjp->klass()  != field()->holder() ||
1603         tjp->offset() != field()->offset_in_bytes()) {
1604       st->print(" != ");
1605       field()->print();
1606       st->print(" ***");
1607     }
1608   }
1609 }
1610 
1611 void print_alias_types() {
1612   Compile* C = Compile::current();
1613   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1614   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1615     C->alias_type(idx)->print_on(tty);
1616     tty->cr();
1617   }
1618 }
1619 #endif
1620 
1621 
1622 //----------------------------probe_alias_cache--------------------------------
1623 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1624   intptr_t key = (intptr_t) adr_type;
1625   key ^= key >> logAliasCacheSize;
1626   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1627 }
1628 
1629 
1630 //-----------------------------grow_alias_types--------------------------------
1631 void Compile::grow_alias_types() {
1632   const int old_ats  = _max_alias_types; // how many before?
1633   const int new_ats  = old_ats;          // how many more?
1634   const int grow_ats = old_ats+new_ats;  // how many now?
1635   _max_alias_types = grow_ats;
1636   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1637   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1638   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1639   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1640 }
1641 
1642 
1643 //--------------------------------find_alias_type------------------------------
1644 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1645   if (_AliasLevel == 0)
1646     return alias_type(AliasIdxBot);
1647 
1648   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1649   if (ace->_adr_type == adr_type) {
1650     return alias_type(ace->_index);
1651   }
1652 
1653   // Handle special cases.
1654   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1655   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1656 
1657   // Do it the slow way.
1658   const TypePtr* flat = flatten_alias_type(adr_type);
1659 
1660 #ifdef ASSERT
1661   assert(flat == flatten_alias_type(flat), "idempotent");
1662   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1663   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1664     const TypeOopPtr* foop = flat->is_oopptr();
1665     // Scalarizable allocations have exact klass always.
1666     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1667     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1668     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1669   }
1670   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1671 #endif
1672 
1673   int idx = AliasIdxTop;
1674   for (int i = 0; i < num_alias_types(); i++) {
1675     if (alias_type(i)->adr_type() == flat) {
1676       idx = i;
1677       break;
1678     }
1679   }
1680 
1681   if (idx == AliasIdxTop) {
1682     if (no_create)  return NULL;
1683     // Grow the array if necessary.
1684     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1685     // Add a new alias type.
1686     idx = _num_alias_types++;
1687     _alias_types[idx]->Init(idx, flat);
1688     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1689     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1690     if (flat->isa_instptr()) {
1691       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1692           && flat->is_instptr()->klass() == env()->Class_klass())
1693         alias_type(idx)->set_rewritable(false);
1694     }
1695     if (flat->isa_aryptr()) {
1696 #ifdef ASSERT
1697       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1698       // (T_BYTE has the weakest alignment and size restrictions...)
1699       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1700 #endif
1701       if (flat->offset() == TypePtr::OffsetBot) {
1702         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1703       }
1704     }
1705     if (flat->isa_klassptr()) {
1706       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1707         alias_type(idx)->set_rewritable(false);
1708       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1709         alias_type(idx)->set_rewritable(false);
1710       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1711         alias_type(idx)->set_rewritable(false);
1712       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1713         alias_type(idx)->set_rewritable(false);
1714     }
1715     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1716     // but the base pointer type is not distinctive enough to identify
1717     // references into JavaThread.)
1718 
1719     // Check for final fields.
1720     const TypeInstPtr* tinst = flat->isa_instptr();
1721     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1722       ciField* field;
1723       if (tinst->const_oop() != NULL &&
1724           tinst->klass() == ciEnv::current()->Class_klass() &&
1725           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1726         // static field
1727         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1728         field = k->get_field_by_offset(tinst->offset(), true);
1729       } else {
1730         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1731         field = k->get_field_by_offset(tinst->offset(), false);
1732       }
1733       assert(field == NULL ||
1734              original_field == NULL ||
1735              (field->holder() == original_field->holder() &&
1736               field->offset() == original_field->offset() &&
1737               field->is_static() == original_field->is_static()), "wrong field?");
1738       // Set field() and is_rewritable() attributes.
1739       if (field != NULL)  alias_type(idx)->set_field(field);
1740     }
1741   }
1742 
1743   // Fill the cache for next time.
1744   ace->_adr_type = adr_type;
1745   ace->_index    = idx;
1746   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1747 
1748   // Might as well try to fill the cache for the flattened version, too.
1749   AliasCacheEntry* face = probe_alias_cache(flat);
1750   if (face->_adr_type == NULL) {
1751     face->_adr_type = flat;
1752     face->_index    = idx;
1753     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1754   }
1755 
1756   return alias_type(idx);
1757 }
1758 
1759 
1760 Compile::AliasType* Compile::alias_type(ciField* field) {
1761   const TypeOopPtr* t;
1762   if (field->is_static())
1763     t = TypeInstPtr::make(field->holder()->java_mirror());
1764   else
1765     t = TypeOopPtr::make_from_klass_raw(field->holder());
1766   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1767   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1768   return atp;
1769 }
1770 
1771 
1772 //------------------------------have_alias_type--------------------------------
1773 bool Compile::have_alias_type(const TypePtr* adr_type) {
1774   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1775   if (ace->_adr_type == adr_type) {
1776     return true;
1777   }
1778 
1779   // Handle special cases.
1780   if (adr_type == NULL)             return true;
1781   if (adr_type == TypePtr::BOTTOM)  return true;
1782 
1783   return find_alias_type(adr_type, true, NULL) != NULL;
1784 }
1785 
1786 //-----------------------------must_alias--------------------------------------
1787 // True if all values of the given address type are in the given alias category.
1788 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1789   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1790   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1791   if (alias_idx == AliasIdxTop)         return false; // the empty category
1792   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1793 
1794   // the only remaining possible overlap is identity
1795   int adr_idx = get_alias_index(adr_type);
1796   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1797   assert(adr_idx == alias_idx ||
1798          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1799           && adr_type                       != TypeOopPtr::BOTTOM),
1800          "should not be testing for overlap with an unsafe pointer");
1801   return adr_idx == alias_idx;
1802 }
1803 
1804 //------------------------------can_alias--------------------------------------
1805 // True if any values of the given address type are in the given alias category.
1806 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1807   if (alias_idx == AliasIdxTop)         return false; // the empty category
1808   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1809   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1810   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1811 
1812   // the only remaining possible overlap is identity
1813   int adr_idx = get_alias_index(adr_type);
1814   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1815   return adr_idx == alias_idx;
1816 }
1817 
1818 
1819 
1820 //---------------------------pop_warm_call-------------------------------------
1821 WarmCallInfo* Compile::pop_warm_call() {
1822   WarmCallInfo* wci = _warm_calls;
1823   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1824   return wci;
1825 }
1826 
1827 //----------------------------Inline_Warm--------------------------------------
1828 int Compile::Inline_Warm() {
1829   // If there is room, try to inline some more warm call sites.
1830   // %%% Do a graph index compaction pass when we think we're out of space?
1831   if (!InlineWarmCalls)  return 0;
1832 
1833   int calls_made_hot = 0;
1834   int room_to_grow   = NodeCountInliningCutoff - unique();
1835   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1836   int amount_grown   = 0;
1837   WarmCallInfo* call;
1838   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1839     int est_size = (int)call->size();
1840     if (est_size > (room_to_grow - amount_grown)) {
1841       // This one won't fit anyway.  Get rid of it.
1842       call->make_cold();
1843       continue;
1844     }
1845     call->make_hot();
1846     calls_made_hot++;
1847     amount_grown   += est_size;
1848     amount_to_grow -= est_size;
1849   }
1850 
1851   if (calls_made_hot > 0)  set_major_progress();
1852   return calls_made_hot;
1853 }
1854 
1855 
1856 //----------------------------Finish_Warm--------------------------------------
1857 void Compile::Finish_Warm() {
1858   if (!InlineWarmCalls)  return;
1859   if (failing())  return;
1860   if (warm_calls() == NULL)  return;
1861 
1862   // Clean up loose ends, if we are out of space for inlining.
1863   WarmCallInfo* call;
1864   while ((call = pop_warm_call()) != NULL) {
1865     call->make_cold();
1866   }
1867 }
1868 
1869 //---------------------cleanup_loop_predicates-----------------------
1870 // Remove the opaque nodes that protect the predicates so that all unused
1871 // checks and uncommon_traps will be eliminated from the ideal graph
1872 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1873   if (predicate_count()==0) return;
1874   for (int i = predicate_count(); i > 0; i--) {
1875     Node * n = predicate_opaque1_node(i-1);
1876     assert(n->Opcode() == Op_Opaque1, "must be");
1877     igvn.replace_node(n, n->in(1));
1878   }
1879   assert(predicate_count()==0, "should be clean!");
1880 }
1881 
1882 // StringOpts and late inlining of string methods
1883 void Compile::inline_string_calls(bool parse_time) {
1884   {
1885     // remove useless nodes to make the usage analysis simpler
1886     ResourceMark rm;
1887     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1888   }
1889 
1890   {
1891     ResourceMark rm;
1892     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1893     PhaseStringOpts pso(initial_gvn(), for_igvn());
1894     print_method(PHASE_AFTER_STRINGOPTS, 3);
1895   }
1896 
1897   // now inline anything that we skipped the first time around
1898   if (!parse_time) {
1899     _late_inlines_pos = _late_inlines.length();
1900   }
1901 
1902   while (_string_late_inlines.length() > 0) {
1903     CallGenerator* cg = _string_late_inlines.pop();
1904     cg->do_late_inline();
1905     if (failing())  return;
1906   }
1907   _string_late_inlines.trunc_to(0);
1908 }
1909 
1910 // Late inlining of boxing methods
1911 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1912   if (_boxing_late_inlines.length() > 0) {
1913     assert(has_boxed_value(), "inconsistent");
1914 
1915     PhaseGVN* gvn = initial_gvn();
1916     set_inlining_incrementally(true);
1917 
1918     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1919     for_igvn()->clear();
1920     gvn->replace_with(&igvn);
1921 
1922     _late_inlines_pos = _late_inlines.length();
1923 
1924     while (_boxing_late_inlines.length() > 0) {
1925       CallGenerator* cg = _boxing_late_inlines.pop();
1926       cg->do_late_inline();
1927       if (failing())  return;
1928     }
1929     _boxing_late_inlines.trunc_to(0);
1930 
1931     {
1932       ResourceMark rm;
1933       PhaseRemoveUseless pru(gvn, for_igvn());
1934     }
1935 
1936     igvn = PhaseIterGVN(gvn);
1937     igvn.optimize();
1938 
1939     set_inlining_progress(false);
1940     set_inlining_incrementally(false);
1941   }
1942 }
1943 
1944 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1945   assert(IncrementalInline, "incremental inlining should be on");
1946   PhaseGVN* gvn = initial_gvn();
1947 
1948   set_inlining_progress(false);
1949   for_igvn()->clear();
1950   gvn->replace_with(&igvn);
1951 
1952   int i = 0;
1953 
1954   for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1955     CallGenerator* cg = _late_inlines.at(i);
1956     _late_inlines_pos = i+1;
1957     cg->do_late_inline();
1958     if (failing())  return;
1959   }
1960   int j = 0;
1961   for (; i < _late_inlines.length(); i++, j++) {
1962     _late_inlines.at_put(j, _late_inlines.at(i));
1963   }
1964   _late_inlines.trunc_to(j);
1965 
1966   {
1967     ResourceMark rm;
1968     PhaseRemoveUseless pru(gvn, for_igvn());
1969   }
1970 
1971   igvn = PhaseIterGVN(gvn);
1972 }
1973 
1974 // Perform incremental inlining until bound on number of live nodes is reached
1975 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1976   PhaseGVN* gvn = initial_gvn();
1977 
1978   set_inlining_incrementally(true);
1979   set_inlining_progress(true);
1980   uint low_live_nodes = 0;
1981 
1982   while(inlining_progress() && _late_inlines.length() > 0) {
1983 
1984     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1985       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
1986         // PhaseIdealLoop is expensive so we only try it once we are
1987         // out of live nodes and we only try it again if the previous
1988         // helped got the number of nodes down significantly
1989         PhaseIdealLoop ideal_loop( igvn, false, true );
1990         if (failing())  return;
1991         low_live_nodes = live_nodes();
1992         _major_progress = true;
1993       }
1994 
1995       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1996         break;
1997       }
1998     }
1999 
2000     inline_incrementally_one(igvn);
2001 
2002     if (failing())  return;
2003 
2004     igvn.optimize();
2005 
2006     if (failing())  return;
2007   }
2008 
2009   assert( igvn._worklist.size() == 0, "should be done with igvn" );
2010 
2011   if (_string_late_inlines.length() > 0) {
2012     assert(has_stringbuilder(), "inconsistent");
2013     for_igvn()->clear();
2014     initial_gvn()->replace_with(&igvn);
2015 
2016     inline_string_calls(false);
2017 
2018     if (failing())  return;
2019 
2020     {
2021       ResourceMark rm;
2022       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2023     }
2024 
2025     igvn = PhaseIterGVN(gvn);
2026 
2027     igvn.optimize();
2028   }
2029 
2030   set_inlining_incrementally(false);
2031 }
2032 
2033 
2034 //------------------------------Optimize---------------------------------------
2035 // Given a graph, optimize it.
2036 void Compile::Optimize() {
2037   TracePhase t1("optimizer", &_t_optimizer, true);
2038 
2039 #ifndef PRODUCT
2040   if (env()->break_at_compile()) {
2041     BREAKPOINT;
2042   }
2043 
2044 #endif
2045 
2046   ResourceMark rm;
2047   int          loop_opts_cnt;
2048 
2049   print_inlining_reinit();
2050 
2051   NOT_PRODUCT( verify_graph_edges(); )
2052 
2053   print_method(PHASE_AFTER_PARSING);
2054 
2055  {
2056   // Iterative Global Value Numbering, including ideal transforms
2057   // Initialize IterGVN with types and values from parse-time GVN
2058   PhaseIterGVN igvn(initial_gvn());
2059 #ifdef ASSERT
2060   _modified_nodes = new (comp_arena()) Unique_Node_List(comp_arena());
2061 #endif
2062   {
2063     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2064     igvn.optimize();
2065   }
2066 
2067   print_method(PHASE_ITER_GVN1, 2);
2068 
2069   if (failing())  return;
2070 
2071   {
2072     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2073     inline_incrementally(igvn);
2074   }
2075 
2076   print_method(PHASE_INCREMENTAL_INLINE, 2);
2077 
2078   if (failing())  return;
2079 
2080   if (eliminate_boxing()) {
2081     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2082     // Inline valueOf() methods now.
2083     inline_boxing_calls(igvn);
2084 
2085     if (AlwaysIncrementalInline) {
2086       inline_incrementally(igvn);
2087     }
2088 
2089     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2090 
2091     if (failing())  return;
2092   }
2093 
2094   // Remove the speculative part of types and clean up the graph from
2095   // the extra CastPP nodes whose only purpose is to carry them. Do
2096   // that early so that optimizations are not disrupted by the extra
2097   // CastPP nodes.
2098   remove_speculative_types(igvn);
2099 
2100   // No more new expensive nodes will be added to the list from here
2101   // so keep only the actual candidates for optimizations.
2102   cleanup_expensive_nodes(igvn);
2103 
2104   // Perform escape analysis
2105   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2106     if (has_loops()) {
2107       // Cleanup graph (remove dead nodes).
2108       TracePhase t2("idealLoop", &_t_idealLoop, true);
2109       PhaseIdealLoop ideal_loop( igvn, false, true );
2110       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2111       if (failing())  return;
2112     }
2113     ConnectionGraph::do_analysis(this, &igvn);
2114 
2115     if (failing())  return;
2116 
2117     // Optimize out fields loads from scalar replaceable allocations.
2118     igvn.optimize();
2119     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2120 
2121     if (failing())  return;
2122 
2123     if (congraph() != NULL && macro_count() > 0) {
2124       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2125       PhaseMacroExpand mexp(igvn);
2126       mexp.eliminate_macro_nodes();
2127       igvn.set_delay_transform(false);
2128 
2129       igvn.optimize();
2130       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2131 
2132       if (failing())  return;
2133     }
2134   }
2135 
2136   // Loop transforms on the ideal graph.  Range Check Elimination,
2137   // peeling, unrolling, etc.
2138 
2139   // Set loop opts counter
2140   loop_opts_cnt = num_loop_opts();
2141   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2142     {
2143       TracePhase t2("idealLoop", &_t_idealLoop, true);
2144       PhaseIdealLoop ideal_loop( igvn, true );
2145       loop_opts_cnt--;
2146       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2147       if (failing())  return;
2148     }
2149     // Loop opts pass if partial peeling occurred in previous pass
2150     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2151       TracePhase t3("idealLoop", &_t_idealLoop, true);
2152       PhaseIdealLoop ideal_loop( igvn, false );
2153       loop_opts_cnt--;
2154       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2155       if (failing())  return;
2156     }
2157     // Loop opts pass for loop-unrolling before CCP
2158     if(major_progress() && (loop_opts_cnt > 0)) {
2159       TracePhase t4("idealLoop", &_t_idealLoop, true);
2160       PhaseIdealLoop ideal_loop( igvn, false );
2161       loop_opts_cnt--;
2162       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2163     }
2164     if (!failing()) {
2165       // Verify that last round of loop opts produced a valid graph
2166       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2167       PhaseIdealLoop::verify(igvn);
2168     }
2169   }
2170   if (failing())  return;
2171 
2172   // Conditional Constant Propagation;
2173   PhaseCCP ccp( &igvn );
2174   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2175   {
2176     TracePhase t2("ccp", &_t_ccp, true);
2177     ccp.do_transform();
2178   }
2179   print_method(PHASE_CPP1, 2);
2180 
2181   assert( true, "Break here to ccp.dump_old2new_map()");
2182 
2183   // Iterative Global Value Numbering, including ideal transforms
2184   {
2185     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2186     igvn = ccp;
2187     igvn.optimize();
2188   }
2189 
2190   print_method(PHASE_ITER_GVN2, 2);
2191 
2192   if (failing())  return;
2193 
2194   // Loop transforms on the ideal graph.  Range Check Elimination,
2195   // peeling, unrolling, etc.
2196   if(loop_opts_cnt > 0) {
2197     debug_only( int cnt = 0; );
2198     while(major_progress() && (loop_opts_cnt > 0)) {
2199       TracePhase t2("idealLoop", &_t_idealLoop, true);
2200       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2201       PhaseIdealLoop ideal_loop( igvn, true);
2202       loop_opts_cnt--;
2203       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2204       if (failing())  return;
2205     }
2206   }
2207 
2208   {
2209     // Verify that all previous optimizations produced a valid graph
2210     // at least to this point, even if no loop optimizations were done.
2211     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2212     PhaseIdealLoop::verify(igvn);
2213   }
2214 
2215   {
2216     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2217     PhaseMacroExpand  mex(igvn);
2218     if (mex.expand_macro_nodes()) {
2219       assert(failing(), "must bail out w/ explicit message");
2220       return;
2221     }
2222   }
2223 
2224   DEBUG_ONLY( _modified_nodes = NULL; )
2225  } // (End scope of igvn; run destructor if necessary for asserts.)
2226 
2227   process_print_inlining();
2228   // A method with only infinite loops has no edges entering loops from root
2229   {
2230     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2231     if (final_graph_reshaping()) {
2232       assert(failing(), "must bail out w/ explicit message");
2233       return;
2234     }
2235   }
2236 
2237   print_method(PHASE_OPTIMIZE_FINISHED, 2);
2238 }
2239 
2240 
2241 //------------------------------Code_Gen---------------------------------------
2242 // Given a graph, generate code for it
2243 void Compile::Code_Gen() {
2244   if (failing()) {
2245     return;
2246   }
2247 
2248   // Perform instruction selection.  You might think we could reclaim Matcher
2249   // memory PDQ, but actually the Matcher is used in generating spill code.
2250   // Internals of the Matcher (including some VectorSets) must remain live
2251   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2252   // set a bit in reclaimed memory.
2253 
2254   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2255   // nodes.  Mapping is only valid at the root of each matched subtree.
2256   NOT_PRODUCT( verify_graph_edges(); )
2257 
2258   Matcher matcher;
2259   _matcher = &matcher;
2260   {
2261     TracePhase t2("matcher", &_t_matcher, true);
2262     matcher.match();
2263   }
2264   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2265   // nodes.  Mapping is only valid at the root of each matched subtree.
2266   NOT_PRODUCT( verify_graph_edges(); )
2267 
2268   // If you have too many nodes, or if matching has failed, bail out
2269   check_node_count(0, "out of nodes matching instructions");
2270   if (failing()) {
2271     return;
2272   }
2273 
2274   // Build a proper-looking CFG
2275   PhaseCFG cfg(node_arena(), root(), matcher);
2276   _cfg = &cfg;
2277   {
2278     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2279     bool success = cfg.do_global_code_motion();
2280     if (!success) {
2281       return;
2282     }
2283 
2284     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2285     NOT_PRODUCT( verify_graph_edges(); )
2286     debug_only( cfg.verify(); )
2287   }
2288 
2289   PhaseChaitin regalloc(unique(), cfg, matcher);
2290   _regalloc = &regalloc;
2291   {
2292     TracePhase t2("regalloc", &_t_registerAllocation, true);
2293     // Perform register allocation.  After Chaitin, use-def chains are
2294     // no longer accurate (at spill code) and so must be ignored.
2295     // Node->LRG->reg mappings are still accurate.
2296     _regalloc->Register_Allocate();
2297 
2298     // Bail out if the allocator builds too many nodes
2299     if (failing()) {
2300       return;
2301     }
2302   }
2303 
2304   // Prior to register allocation we kept empty basic blocks in case the
2305   // the allocator needed a place to spill.  After register allocation we
2306   // are not adding any new instructions.  If any basic block is empty, we
2307   // can now safely remove it.
2308   {
2309     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2310     cfg.remove_empty_blocks();
2311     if (do_freq_based_layout()) {
2312       PhaseBlockLayout layout(cfg);
2313     } else {
2314       cfg.set_loop_alignment();
2315     }
2316     cfg.fixup_flow();
2317   }
2318 
2319   // Apply peephole optimizations
2320   if( OptoPeephole ) {
2321     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2322     PhasePeephole peep( _regalloc, cfg);
2323     peep.do_transform();
2324   }
2325 
2326   // Do late expand if CPU requires this.
2327   if (Matcher::require_postalloc_expand) {
2328     NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));
2329     cfg.postalloc_expand(_regalloc);
2330   }
2331 
2332   // Convert Nodes to instruction bits in a buffer
2333   {
2334     // %%%% workspace merge brought two timers together for one job
2335     TracePhase t2a("output", &_t_output, true);
2336     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2337     Output();
2338   }
2339 
2340   print_method(PHASE_FINAL_CODE);
2341 
2342   // He's dead, Jim.
2343   _cfg     = (PhaseCFG*)0xdeadbeef;
2344   _regalloc = (PhaseChaitin*)0xdeadbeef;
2345 }
2346 
2347 
2348 //------------------------------dump_asm---------------------------------------
2349 // Dump formatted assembly
2350 #ifndef PRODUCT
2351 void Compile::dump_asm(int *pcs, uint pc_limit) {
2352   bool cut_short = false;
2353   tty->print_cr("#");
2354   tty->print("#  ");  _tf->dump();  tty->cr();
2355   tty->print_cr("#");
2356 
2357   // For all blocks
2358   int pc = 0x0;                 // Program counter
2359   char starts_bundle = ' ';
2360   _regalloc->dump_frame();
2361 
2362   Node *n = NULL;
2363   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2364     if (VMThread::should_terminate()) {
2365       cut_short = true;
2366       break;
2367     }
2368     Block* block = _cfg->get_block(i);
2369     if (block->is_connector() && !Verbose) {
2370       continue;
2371     }
2372     n = block->head();
2373     if (pcs && n->_idx < pc_limit) {
2374       tty->print("%3.3x   ", pcs[n->_idx]);
2375     } else {
2376       tty->print("      ");
2377     }
2378     block->dump_head(_cfg);
2379     if (block->is_connector()) {
2380       tty->print_cr("        # Empty connector block");
2381     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2382       tty->print_cr("        # Block is sole successor of call");
2383     }
2384 
2385     // For all instructions
2386     Node *delay = NULL;
2387     for (uint j = 0; j < block->number_of_nodes(); j++) {
2388       if (VMThread::should_terminate()) {
2389         cut_short = true;
2390         break;
2391       }
2392       n = block->get_node(j);
2393       if (valid_bundle_info(n)) {
2394         Bundle* bundle = node_bundling(n);
2395         if (bundle->used_in_unconditional_delay()) {
2396           delay = n;
2397           continue;
2398         }
2399         if (bundle->starts_bundle()) {
2400           starts_bundle = '+';
2401         }
2402       }
2403 
2404       if (WizardMode) {
2405         n->dump();
2406       }
2407 
2408       if( !n->is_Region() &&    // Dont print in the Assembly
2409           !n->is_Phi() &&       // a few noisely useless nodes
2410           !n->is_Proj() &&
2411           !n->is_MachTemp() &&
2412           !n->is_SafePointScalarObject() &&
2413           !n->is_Catch() &&     // Would be nice to print exception table targets
2414           !n->is_MergeMem() &&  // Not very interesting
2415           !n->is_top() &&       // Debug info table constants
2416           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2417           ) {
2418         if (pcs && n->_idx < pc_limit)
2419           tty->print("%3.3x", pcs[n->_idx]);
2420         else
2421           tty->print("   ");
2422         tty->print(" %c ", starts_bundle);
2423         starts_bundle = ' ';
2424         tty->print("\t");
2425         n->format(_regalloc, tty);
2426         tty->cr();
2427       }
2428 
2429       // If we have an instruction with a delay slot, and have seen a delay,
2430       // then back up and print it
2431       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2432         assert(delay != NULL, "no unconditional delay instruction");
2433         if (WizardMode) delay->dump();
2434 
2435         if (node_bundling(delay)->starts_bundle())
2436           starts_bundle = '+';
2437         if (pcs && n->_idx < pc_limit)
2438           tty->print("%3.3x", pcs[n->_idx]);
2439         else
2440           tty->print("   ");
2441         tty->print(" %c ", starts_bundle);
2442         starts_bundle = ' ';
2443         tty->print("\t");
2444         delay->format(_regalloc, tty);
2445         tty->cr();
2446         delay = NULL;
2447       }
2448 
2449       // Dump the exception table as well
2450       if( n->is_Catch() && (Verbose || WizardMode) ) {
2451         // Print the exception table for this offset
2452         _handler_table.print_subtable_for(pc);
2453       }
2454     }
2455 
2456     if (pcs && n->_idx < pc_limit)
2457       tty->print_cr("%3.3x", pcs[n->_idx]);
2458     else
2459       tty->cr();
2460 
2461     assert(cut_short || delay == NULL, "no unconditional delay branch");
2462 
2463   } // End of per-block dump
2464   tty->cr();
2465 
2466   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2467 }
2468 #endif
2469 
2470 //------------------------------Final_Reshape_Counts---------------------------
2471 // This class defines counters to help identify when a method
2472 // may/must be executed using hardware with only 24-bit precision.
2473 struct Final_Reshape_Counts : public StackObj {
2474   int  _call_count;             // count non-inlined 'common' calls
2475   int  _float_count;            // count float ops requiring 24-bit precision
2476   int  _double_count;           // count double ops requiring more precision
2477   int  _java_call_count;        // count non-inlined 'java' calls
2478   int  _inner_loop_count;       // count loops which need alignment
2479   VectorSet _visited;           // Visitation flags
2480   Node_List _tests;             // Set of IfNodes & PCTableNodes
2481 
2482   Final_Reshape_Counts() :
2483     _call_count(0), _float_count(0), _double_count(0),
2484     _java_call_count(0), _inner_loop_count(0),
2485     _visited( Thread::current()->resource_area() ) { }
2486 
2487   void inc_call_count  () { _call_count  ++; }
2488   void inc_float_count () { _float_count ++; }
2489   void inc_double_count() { _double_count++; }
2490   void inc_java_call_count() { _java_call_count++; }
2491   void inc_inner_loop_count() { _inner_loop_count++; }
2492 
2493   int  get_call_count  () const { return _call_count  ; }
2494   int  get_float_count () const { return _float_count ; }
2495   int  get_double_count() const { return _double_count; }
2496   int  get_java_call_count() const { return _java_call_count; }
2497   int  get_inner_loop_count() const { return _inner_loop_count; }
2498 };
2499 
2500 #ifdef ASSERT
2501 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2502   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2503   // Make sure the offset goes inside the instance layout.
2504   return k->contains_field_offset(tp->offset());
2505   // Note that OffsetBot and OffsetTop are very negative.
2506 }
2507 #endif
2508 
2509 // Eliminate trivially redundant StoreCMs and accumulate their
2510 // precedence edges.
2511 void Compile::eliminate_redundant_card_marks(Node* n) {
2512   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2513   if (n->in(MemNode::Address)->outcnt() > 1) {
2514     // There are multiple users of the same address so it might be
2515     // possible to eliminate some of the StoreCMs
2516     Node* mem = n->in(MemNode::Memory);
2517     Node* adr = n->in(MemNode::Address);
2518     Node* val = n->in(MemNode::ValueIn);
2519     Node* prev = n;
2520     bool done = false;
2521     // Walk the chain of StoreCMs eliminating ones that match.  As
2522     // long as it's a chain of single users then the optimization is
2523     // safe.  Eliminating partially redundant StoreCMs would require
2524     // cloning copies down the other paths.
2525     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2526       if (adr == mem->in(MemNode::Address) &&
2527           val == mem->in(MemNode::ValueIn)) {
2528         // redundant StoreCM
2529         if (mem->req() > MemNode::OopStore) {
2530           // Hasn't been processed by this code yet.
2531           n->add_prec(mem->in(MemNode::OopStore));
2532         } else {
2533           // Already converted to precedence edge
2534           for (uint i = mem->req(); i < mem->len(); i++) {
2535             // Accumulate any precedence edges
2536             if (mem->in(i) != NULL) {
2537               n->add_prec(mem->in(i));
2538             }
2539           }
2540           // Everything above this point has been processed.
2541           done = true;
2542         }
2543         // Eliminate the previous StoreCM
2544         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2545         assert(mem->outcnt() == 0, "should be dead");
2546         mem->disconnect_inputs(NULL, this);
2547       } else {
2548         prev = mem;
2549       }
2550       mem = prev->in(MemNode::Memory);
2551     }
2552   }
2553 }
2554 
2555 //------------------------------final_graph_reshaping_impl----------------------
2556 // Implement items 1-5 from final_graph_reshaping below.
2557 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2558 
2559   if ( n->outcnt() == 0 ) return; // dead node
2560   uint nop = n->Opcode();
2561 
2562   // Check for 2-input instruction with "last use" on right input.
2563   // Swap to left input.  Implements item (2).
2564   if( n->req() == 3 &&          // two-input instruction
2565       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2566       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2567       n->in(2)->outcnt() == 1 &&// right use IS a last use
2568       !n->in(2)->is_Con() ) {   // right use is not a constant
2569     // Check for commutative opcode
2570     switch( nop ) {
2571     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2572     case Op_MaxI:  case Op_MinI:
2573     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2574     case Op_AndL:  case Op_XorL:  case Op_OrL:
2575     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2576       // Move "last use" input to left by swapping inputs
2577       n->swap_edges(1, 2);
2578       break;
2579     }
2580     default:
2581       break;
2582     }
2583   }
2584 
2585 #ifdef ASSERT
2586   if( n->is_Mem() ) {
2587     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2588     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2589             // oop will be recorded in oop map if load crosses safepoint
2590             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2591                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2592             "raw memory operations should have control edge");
2593   }
2594 #endif
2595   // Count FPU ops and common calls, implements item (3)
2596   switch( nop ) {
2597   // Count all float operations that may use FPU
2598   case Op_AddF:
2599   case Op_SubF:
2600   case Op_MulF:
2601   case Op_DivF:
2602   case Op_NegF:
2603   case Op_ModF:
2604   case Op_ConvI2F:
2605   case Op_ConF:
2606   case Op_CmpF:
2607   case Op_CmpF3:
2608   // case Op_ConvL2F: // longs are split into 32-bit halves
2609     frc.inc_float_count();
2610     break;
2611 
2612   case Op_ConvF2D:
2613   case Op_ConvD2F:
2614     frc.inc_float_count();
2615     frc.inc_double_count();
2616     break;
2617 
2618   // Count all double operations that may use FPU
2619   case Op_AddD:
2620   case Op_SubD:
2621   case Op_MulD:
2622   case Op_DivD:
2623   case Op_NegD:
2624   case Op_ModD:
2625   case Op_ConvI2D:
2626   case Op_ConvD2I:
2627   // case Op_ConvL2D: // handled by leaf call
2628   // case Op_ConvD2L: // handled by leaf call
2629   case Op_ConD:
2630   case Op_CmpD:
2631   case Op_CmpD3:
2632     frc.inc_double_count();
2633     break;
2634   case Op_Opaque1:              // Remove Opaque Nodes before matching
2635   case Op_Opaque2:              // Remove Opaque Nodes before matching
2636   case Op_Opaque3:
2637     n->subsume_by(n->in(1), this);
2638     break;
2639   case Op_CallStaticJava:
2640   case Op_CallJava:
2641   case Op_CallDynamicJava:
2642     frc.inc_java_call_count(); // Count java call site;
2643   case Op_CallRuntime:
2644   case Op_CallLeaf:
2645   case Op_CallLeafNoFP: {
2646     assert( n->is_Call(), "" );
2647     CallNode *call = n->as_Call();
2648     // Count call sites where the FP mode bit would have to be flipped.
2649     // Do not count uncommon runtime calls:
2650     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2651     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2652     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2653       frc.inc_call_count();   // Count the call site
2654     } else {                  // See if uncommon argument is shared
2655       Node *n = call->in(TypeFunc::Parms);
2656       int nop = n->Opcode();
2657       // Clone shared simple arguments to uncommon calls, item (1).
2658       if( n->outcnt() > 1 &&
2659           !n->is_Proj() &&
2660           nop != Op_CreateEx &&
2661           nop != Op_CheckCastPP &&
2662           nop != Op_DecodeN &&
2663           nop != Op_DecodeNKlass &&
2664           !n->is_Mem() ) {
2665         Node *x = n->clone();
2666         call->set_req( TypeFunc::Parms, x );
2667       }
2668     }
2669     break;
2670   }
2671 
2672   case Op_StoreD:
2673   case Op_LoadD:
2674   case Op_LoadD_unaligned:
2675     frc.inc_double_count();
2676     goto handle_mem;
2677   case Op_StoreF:
2678   case Op_LoadF:
2679     frc.inc_float_count();
2680     goto handle_mem;
2681 
2682   case Op_StoreCM:
2683     {
2684       // Convert OopStore dependence into precedence edge
2685       Node* prec = n->in(MemNode::OopStore);
2686       n->del_req(MemNode::OopStore);
2687       n->add_prec(prec);
2688       eliminate_redundant_card_marks(n);
2689     }
2690 
2691     // fall through
2692 
2693   case Op_StoreB:
2694   case Op_StoreC:
2695   case Op_StorePConditional:
2696   case Op_StoreI:
2697   case Op_StoreL:
2698   case Op_StoreIConditional:
2699   case Op_StoreLConditional:
2700   case Op_CompareAndSwapI:
2701   case Op_CompareAndSwapL:
2702   case Op_CompareAndSwapP:
2703   case Op_CompareAndSwapN:
2704   case Op_GetAndAddI:
2705   case Op_GetAndAddL:
2706   case Op_GetAndSetI:
2707   case Op_GetAndSetL:
2708   case Op_GetAndSetP:
2709   case Op_GetAndSetN:
2710   case Op_StoreP:
2711   case Op_StoreN:
2712   case Op_StoreNKlass:
2713   case Op_LoadB:
2714   case Op_LoadUB:
2715   case Op_LoadUS:
2716   case Op_LoadI:
2717   case Op_LoadKlass:
2718   case Op_LoadNKlass:
2719   case Op_LoadL:
2720   case Op_LoadL_unaligned:
2721   case Op_LoadPLocked:
2722   case Op_LoadP:
2723   case Op_LoadN:
2724   case Op_LoadRange:
2725   case Op_LoadS: {
2726   handle_mem:
2727 #ifdef ASSERT
2728     if( VerifyOptoOopOffsets ) {
2729       assert( n->is_Mem(), "" );
2730       MemNode *mem  = (MemNode*)n;
2731       // Check to see if address types have grounded out somehow.
2732       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2733       assert( !tp || oop_offset_is_sane(tp), "" );
2734     }
2735 #endif
2736     break;
2737   }
2738 
2739   case Op_AddP: {               // Assert sane base pointers
2740     Node *addp = n->in(AddPNode::Address);
2741     assert( !addp->is_AddP() ||
2742             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2743             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2744             "Base pointers must match" );
2745 #ifdef _LP64
2746     if ((UseCompressedOops || UseCompressedClassPointers) &&
2747         addp->Opcode() == Op_ConP &&
2748         addp == n->in(AddPNode::Base) &&
2749         n->in(AddPNode::Offset)->is_Con()) {
2750       // Use addressing with narrow klass to load with offset on x86.
2751       // On sparc loading 32-bits constant and decoding it have less
2752       // instructions (4) then load 64-bits constant (7).
2753       // Do this transformation here since IGVN will convert ConN back to ConP.
2754       const Type* t = addp->bottom_type();
2755       if (t->isa_oopptr() || t->isa_klassptr()) {
2756         Node* nn = NULL;
2757 
2758         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2759 
2760         // Look for existing ConN node of the same exact type.
2761         Node* r  = root();
2762         uint cnt = r->outcnt();
2763         for (uint i = 0; i < cnt; i++) {
2764           Node* m = r->raw_out(i);
2765           if (m!= NULL && m->Opcode() == op &&
2766               m->bottom_type()->make_ptr() == t) {
2767             nn = m;
2768             break;
2769           }
2770         }
2771         if (nn != NULL) {
2772           // Decode a narrow oop to match address
2773           // [R12 + narrow_oop_reg<<3 + offset]
2774           if (t->isa_oopptr()) {
2775             nn = new DecodeNNode(nn, t);
2776           } else {
2777             nn = new DecodeNKlassNode(nn, t);
2778           }
2779           n->set_req(AddPNode::Base, nn);
2780           n->set_req(AddPNode::Address, nn);
2781           if (addp->outcnt() == 0) {
2782             addp->disconnect_inputs(NULL, this);
2783           }
2784         }
2785       }
2786     }
2787 #endif
2788     break;
2789   }
2790 
2791 #ifdef _LP64
2792   case Op_CastPP:
2793     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2794       Node* in1 = n->in(1);
2795       const Type* t = n->bottom_type();
2796       Node* new_in1 = in1->clone();
2797       new_in1->as_DecodeN()->set_type(t);
2798 
2799       if (!Matcher::narrow_oop_use_complex_address()) {
2800         //
2801         // x86, ARM and friends can handle 2 adds in addressing mode
2802         // and Matcher can fold a DecodeN node into address by using
2803         // a narrow oop directly and do implicit NULL check in address:
2804         //
2805         // [R12 + narrow_oop_reg<<3 + offset]
2806         // NullCheck narrow_oop_reg
2807         //
2808         // On other platforms (Sparc) we have to keep new DecodeN node and
2809         // use it to do implicit NULL check in address:
2810         //
2811         // decode_not_null narrow_oop_reg, base_reg
2812         // [base_reg + offset]
2813         // NullCheck base_reg
2814         //
2815         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2816         // to keep the information to which NULL check the new DecodeN node
2817         // corresponds to use it as value in implicit_null_check().
2818         //
2819         new_in1->set_req(0, n->in(0));
2820       }
2821 
2822       n->subsume_by(new_in1, this);
2823       if (in1->outcnt() == 0) {
2824         in1->disconnect_inputs(NULL, this);
2825       }
2826     }
2827     break;
2828 
2829   case Op_CmpP:
2830     // Do this transformation here to preserve CmpPNode::sub() and
2831     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2832     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2833       Node* in1 = n->in(1);
2834       Node* in2 = n->in(2);
2835       if (!in1->is_DecodeNarrowPtr()) {
2836         in2 = in1;
2837         in1 = n->in(2);
2838       }
2839       assert(in1->is_DecodeNarrowPtr(), "sanity");
2840 
2841       Node* new_in2 = NULL;
2842       if (in2->is_DecodeNarrowPtr()) {
2843         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2844         new_in2 = in2->in(1);
2845       } else if (in2->Opcode() == Op_ConP) {
2846         const Type* t = in2->bottom_type();
2847         if (t == TypePtr::NULL_PTR) {
2848           assert(in1->is_DecodeN(), "compare klass to null?");
2849           // Don't convert CmpP null check into CmpN if compressed
2850           // oops implicit null check is not generated.
2851           // This will allow to generate normal oop implicit null check.
2852           if (Matcher::gen_narrow_oop_implicit_null_checks())
2853             new_in2 = ConNode::make(TypeNarrowOop::NULL_PTR);
2854           //
2855           // This transformation together with CastPP transformation above
2856           // will generated code for implicit NULL checks for compressed oops.
2857           //
2858           // The original code after Optimize()
2859           //
2860           //    LoadN memory, narrow_oop_reg
2861           //    decode narrow_oop_reg, base_reg
2862           //    CmpP base_reg, NULL
2863           //    CastPP base_reg // NotNull
2864           //    Load [base_reg + offset], val_reg
2865           //
2866           // after these transformations will be
2867           //
2868           //    LoadN memory, narrow_oop_reg
2869           //    CmpN narrow_oop_reg, NULL
2870           //    decode_not_null narrow_oop_reg, base_reg
2871           //    Load [base_reg + offset], val_reg
2872           //
2873           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2874           // since narrow oops can be used in debug info now (see the code in
2875           // final_graph_reshaping_walk()).
2876           //
2877           // At the end the code will be matched to
2878           // on x86:
2879           //
2880           //    Load_narrow_oop memory, narrow_oop_reg
2881           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2882           //    NullCheck narrow_oop_reg
2883           //
2884           // and on sparc:
2885           //
2886           //    Load_narrow_oop memory, narrow_oop_reg
2887           //    decode_not_null narrow_oop_reg, base_reg
2888           //    Load [base_reg + offset], val_reg
2889           //    NullCheck base_reg
2890           //
2891         } else if (t->isa_oopptr()) {
2892           new_in2 = ConNode::make(t->make_narrowoop());
2893         } else if (t->isa_klassptr()) {
2894           new_in2 = ConNode::make(t->make_narrowklass());
2895         }
2896       }
2897       if (new_in2 != NULL) {
2898         Node* cmpN = new CmpNNode(in1->in(1), new_in2);
2899         n->subsume_by(cmpN, this);
2900         if (in1->outcnt() == 0) {
2901           in1->disconnect_inputs(NULL, this);
2902         }
2903         if (in2->outcnt() == 0) {
2904           in2->disconnect_inputs(NULL, this);
2905         }
2906       }
2907     }
2908     break;
2909 
2910   case Op_DecodeN:
2911   case Op_DecodeNKlass:
2912     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2913     // DecodeN could be pinned when it can't be fold into
2914     // an address expression, see the code for Op_CastPP above.
2915     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2916     break;
2917 
2918   case Op_EncodeP:
2919   case Op_EncodePKlass: {
2920     Node* in1 = n->in(1);
2921     if (in1->is_DecodeNarrowPtr()) {
2922       n->subsume_by(in1->in(1), this);
2923     } else if (in1->Opcode() == Op_ConP) {
2924       const Type* t = in1->bottom_type();
2925       if (t == TypePtr::NULL_PTR) {
2926         assert(t->isa_oopptr(), "null klass?");
2927         n->subsume_by(ConNode::make(TypeNarrowOop::NULL_PTR), this);
2928       } else if (t->isa_oopptr()) {
2929         n->subsume_by(ConNode::make(t->make_narrowoop()), this);
2930       } else if (t->isa_klassptr()) {
2931         n->subsume_by(ConNode::make(t->make_narrowklass()), this);
2932       }
2933     }
2934     if (in1->outcnt() == 0) {
2935       in1->disconnect_inputs(NULL, this);
2936     }
2937     break;
2938   }
2939 
2940   case Op_Proj: {
2941     if (OptimizeStringConcat) {
2942       ProjNode* p = n->as_Proj();
2943       if (p->_is_io_use) {
2944         // Separate projections were used for the exception path which
2945         // are normally removed by a late inline.  If it wasn't inlined
2946         // then they will hang around and should just be replaced with
2947         // the original one.
2948         Node* proj = NULL;
2949         // Replace with just one
2950         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2951           Node *use = i.get();
2952           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2953             proj = use;
2954             break;
2955           }
2956         }
2957         assert(proj != NULL, "must be found");
2958         p->subsume_by(proj, this);
2959       }
2960     }
2961     break;
2962   }
2963 
2964   case Op_Phi:
2965     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2966       // The EncodeP optimization may create Phi with the same edges
2967       // for all paths. It is not handled well by Register Allocator.
2968       Node* unique_in = n->in(1);
2969       assert(unique_in != NULL, "");
2970       uint cnt = n->req();
2971       for (uint i = 2; i < cnt; i++) {
2972         Node* m = n->in(i);
2973         assert(m != NULL, "");
2974         if (unique_in != m)
2975           unique_in = NULL;
2976       }
2977       if (unique_in != NULL) {
2978         n->subsume_by(unique_in, this);
2979       }
2980     }
2981     break;
2982 
2983 #endif
2984 
2985   case Op_ModI:
2986     if (UseDivMod) {
2987       // Check if a%b and a/b both exist
2988       Node* d = n->find_similar(Op_DivI);
2989       if (d) {
2990         // Replace them with a fused divmod if supported
2991         if (Matcher::has_match_rule(Op_DivModI)) {
2992           DivModINode* divmod = DivModINode::make(n);
2993           d->subsume_by(divmod->div_proj(), this);
2994           n->subsume_by(divmod->mod_proj(), this);
2995         } else {
2996           // replace a%b with a-((a/b)*b)
2997           Node* mult = new MulINode(d, d->in(2));
2998           Node* sub  = new SubINode(d->in(1), mult);
2999           n->subsume_by(sub, this);
3000         }
3001       }
3002     }
3003     break;
3004 
3005   case Op_ModL:
3006     if (UseDivMod) {
3007       // Check if a%b and a/b both exist
3008       Node* d = n->find_similar(Op_DivL);
3009       if (d) {
3010         // Replace them with a fused divmod if supported
3011         if (Matcher::has_match_rule(Op_DivModL)) {
3012           DivModLNode* divmod = DivModLNode::make(n);
3013           d->subsume_by(divmod->div_proj(), this);
3014           n->subsume_by(divmod->mod_proj(), this);
3015         } else {
3016           // replace a%b with a-((a/b)*b)
3017           Node* mult = new MulLNode(d, d->in(2));
3018           Node* sub  = new SubLNode(d->in(1), mult);
3019           n->subsume_by(sub, this);
3020         }
3021       }
3022     }
3023     break;
3024 
3025   case Op_LoadVector:
3026   case Op_StoreVector:
3027     break;
3028 
3029   case Op_PackB:
3030   case Op_PackS:
3031   case Op_PackI:
3032   case Op_PackF:
3033   case Op_PackL:
3034   case Op_PackD:
3035     if (n->req()-1 > 2) {
3036       // Replace many operand PackNodes with a binary tree for matching
3037       PackNode* p = (PackNode*) n;
3038       Node* btp = p->binary_tree_pack(1, n->req());
3039       n->subsume_by(btp, this);
3040     }
3041     break;
3042   case Op_Loop:
3043   case Op_CountedLoop:
3044     if (n->as_Loop()->is_inner_loop()) {
3045       frc.inc_inner_loop_count();
3046     }
3047     break;
3048   case Op_LShiftI:
3049   case Op_RShiftI:
3050   case Op_URShiftI:
3051   case Op_LShiftL:
3052   case Op_RShiftL:
3053   case Op_URShiftL:
3054     if (Matcher::need_masked_shift_count) {
3055       // The cpu's shift instructions don't restrict the count to the
3056       // lower 5/6 bits. We need to do the masking ourselves.
3057       Node* in2 = n->in(2);
3058       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3059       const TypeInt* t = in2->find_int_type();
3060       if (t != NULL && t->is_con()) {
3061         juint shift = t->get_con();
3062         if (shift > mask) { // Unsigned cmp
3063           n->set_req(2, ConNode::make(TypeInt::make(shift & mask)));
3064         }
3065       } else {
3066         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3067           Node* shift = new AndINode(in2, ConNode::make(TypeInt::make(mask)));
3068           n->set_req(2, shift);
3069         }
3070       }
3071       if (in2->outcnt() == 0) { // Remove dead node
3072         in2->disconnect_inputs(NULL, this);
3073       }
3074     }
3075     break;
3076   case Op_MemBarStoreStore:
3077   case Op_MemBarRelease:
3078     // Break the link with AllocateNode: it is no longer useful and
3079     // confuses register allocation.
3080     if (n->req() > MemBarNode::Precedent) {
3081       n->set_req(MemBarNode::Precedent, top());
3082     }
3083     break;
3084   default:
3085     assert( !n->is_Call(), "" );
3086     assert( !n->is_Mem(), "" );
3087     break;
3088   }
3089 
3090   // Collect CFG split points
3091   if (n->is_MultiBranch())
3092     frc._tests.push(n);
3093 }
3094 
3095 //------------------------------final_graph_reshaping_walk---------------------
3096 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3097 // requires that the walk visits a node's inputs before visiting the node.
3098 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3099   ResourceArea *area = Thread::current()->resource_area();
3100   Unique_Node_List sfpt(area);
3101 
3102   frc._visited.set(root->_idx); // first, mark node as visited
3103   uint cnt = root->req();
3104   Node *n = root;
3105   uint  i = 0;
3106   while (true) {
3107     if (i < cnt) {
3108       // Place all non-visited non-null inputs onto stack
3109       Node* m = n->in(i);
3110       ++i;
3111       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3112         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3113           // compute worst case interpreter size in case of a deoptimization
3114           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3115 
3116           sfpt.push(m);
3117         }
3118         cnt = m->req();
3119         nstack.push(n, i); // put on stack parent and next input's index
3120         n = m;
3121         i = 0;
3122       }
3123     } else {
3124       // Now do post-visit work
3125       final_graph_reshaping_impl( n, frc );
3126       if (nstack.is_empty())
3127         break;             // finished
3128       n = nstack.node();   // Get node from stack
3129       cnt = n->req();
3130       i = nstack.index();
3131       nstack.pop();        // Shift to the next node on stack
3132     }
3133   }
3134 
3135   // Skip next transformation if compressed oops are not used.
3136   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3137       (!UseCompressedOops && !UseCompressedClassPointers))
3138     return;
3139 
3140   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3141   // It could be done for an uncommon traps or any safepoints/calls
3142   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3143   while (sfpt.size() > 0) {
3144     n = sfpt.pop();
3145     JVMState *jvms = n->as_SafePoint()->jvms();
3146     assert(jvms != NULL, "sanity");
3147     int start = jvms->debug_start();
3148     int end   = n->req();
3149     bool is_uncommon = (n->is_CallStaticJava() &&
3150                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3151     for (int j = start; j < end; j++) {
3152       Node* in = n->in(j);
3153       if (in->is_DecodeNarrowPtr()) {
3154         bool safe_to_skip = true;
3155         if (!is_uncommon ) {
3156           // Is it safe to skip?
3157           for (uint i = 0; i < in->outcnt(); i++) {
3158             Node* u = in->raw_out(i);
3159             if (!u->is_SafePoint() ||
3160                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3161               safe_to_skip = false;
3162             }
3163           }
3164         }
3165         if (safe_to_skip) {
3166           n->set_req(j, in->in(1));
3167         }
3168         if (in->outcnt() == 0) {
3169           in->disconnect_inputs(NULL, this);
3170         }
3171       }
3172     }
3173   }
3174 }
3175 
3176 //------------------------------final_graph_reshaping--------------------------
3177 // Final Graph Reshaping.
3178 //
3179 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3180 //     and not commoned up and forced early.  Must come after regular
3181 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3182 //     inputs to Loop Phis; these will be split by the allocator anyways.
3183 //     Remove Opaque nodes.
3184 // (2) Move last-uses by commutative operations to the left input to encourage
3185 //     Intel update-in-place two-address operations and better register usage
3186 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3187 //     calls canonicalizing them back.
3188 // (3) Count the number of double-precision FP ops, single-precision FP ops
3189 //     and call sites.  On Intel, we can get correct rounding either by
3190 //     forcing singles to memory (requires extra stores and loads after each
3191 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3192 //     clearing the mode bit around call sites).  The mode bit is only used
3193 //     if the relative frequency of single FP ops to calls is low enough.
3194 //     This is a key transform for SPEC mpeg_audio.
3195 // (4) Detect infinite loops; blobs of code reachable from above but not
3196 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3197 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3198 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3199 //     Detection is by looking for IfNodes where only 1 projection is
3200 //     reachable from below or CatchNodes missing some targets.
3201 // (5) Assert for insane oop offsets in debug mode.
3202 
3203 bool Compile::final_graph_reshaping() {
3204   // an infinite loop may have been eliminated by the optimizer,
3205   // in which case the graph will be empty.
3206   if (root()->req() == 1) {
3207     record_method_not_compilable("trivial infinite loop");
3208     return true;
3209   }
3210 
3211   // Expensive nodes have their control input set to prevent the GVN
3212   // from freely commoning them. There's no GVN beyond this point so
3213   // no need to keep the control input. We want the expensive nodes to
3214   // be freely moved to the least frequent code path by gcm.
3215   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3216   for (int i = 0; i < expensive_count(); i++) {
3217     _expensive_nodes->at(i)->set_req(0, NULL);
3218   }
3219 
3220   Final_Reshape_Counts frc;
3221 
3222   // Visit everybody reachable!
3223   // Allocate stack of size C->unique()/2 to avoid frequent realloc
3224   Node_Stack nstack(unique() >> 1);
3225   final_graph_reshaping_walk(nstack, root(), frc);
3226 
3227   // Check for unreachable (from below) code (i.e., infinite loops).
3228   for( uint i = 0; i < frc._tests.size(); i++ ) {
3229     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3230     // Get number of CFG targets.
3231     // Note that PCTables include exception targets after calls.
3232     uint required_outcnt = n->required_outcnt();
3233     if (n->outcnt() != required_outcnt) {
3234       // Check for a few special cases.  Rethrow Nodes never take the
3235       // 'fall-thru' path, so expected kids is 1 less.
3236       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3237         if (n->in(0)->in(0)->is_Call()) {
3238           CallNode *call = n->in(0)->in(0)->as_Call();
3239           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3240             required_outcnt--;      // Rethrow always has 1 less kid
3241           } else if (call->req() > TypeFunc::Parms &&
3242                      call->is_CallDynamicJava()) {
3243             // Check for null receiver. In such case, the optimizer has
3244             // detected that the virtual call will always result in a null
3245             // pointer exception. The fall-through projection of this CatchNode
3246             // will not be populated.
3247             Node *arg0 = call->in(TypeFunc::Parms);
3248             if (arg0->is_Type() &&
3249                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3250               required_outcnt--;
3251             }
3252           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3253                      call->req() > TypeFunc::Parms+1 &&
3254                      call->is_CallStaticJava()) {
3255             // Check for negative array length. In such case, the optimizer has
3256             // detected that the allocation attempt will always result in an
3257             // exception. There is no fall-through projection of this CatchNode .
3258             Node *arg1 = call->in(TypeFunc::Parms+1);
3259             if (arg1->is_Type() &&
3260                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3261               required_outcnt--;
3262             }
3263           }
3264         }
3265       }
3266       // Recheck with a better notion of 'required_outcnt'
3267       if (n->outcnt() != required_outcnt) {
3268         record_method_not_compilable("malformed control flow");
3269         return true;            // Not all targets reachable!
3270       }
3271     }
3272     // Check that I actually visited all kids.  Unreached kids
3273     // must be infinite loops.
3274     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3275       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3276         record_method_not_compilable("infinite loop");
3277         return true;            // Found unvisited kid; must be unreach
3278       }
3279   }
3280 
3281   // If original bytecodes contained a mixture of floats and doubles
3282   // check if the optimizer has made it homogenous, item (3).
3283   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3284       frc.get_float_count() > 32 &&
3285       frc.get_double_count() == 0 &&
3286       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3287     set_24_bit_selection_and_mode( false,  true );
3288   }
3289 
3290   set_java_calls(frc.get_java_call_count());
3291   set_inner_loops(frc.get_inner_loop_count());
3292 
3293   // No infinite loops, no reason to bail out.
3294   return false;
3295 }
3296 
3297 //-----------------------------too_many_traps----------------------------------
3298 // Report if there are too many traps at the current method and bci.
3299 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3300 bool Compile::too_many_traps(ciMethod* method,
3301                              int bci,
3302                              Deoptimization::DeoptReason reason) {
3303   ciMethodData* md = method->method_data();
3304   if (md->is_empty()) {
3305     // Assume the trap has not occurred, or that it occurred only
3306     // because of a transient condition during start-up in the interpreter.
3307     return false;
3308   }
3309   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3310   if (md->has_trap_at(bci, m, reason) != 0) {
3311     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3312     // Also, if there are multiple reasons, or if there is no per-BCI record,
3313     // assume the worst.
3314     if (log())
3315       log()->elem("observe trap='%s' count='%d'",
3316                   Deoptimization::trap_reason_name(reason),
3317                   md->trap_count(reason));
3318     return true;
3319   } else {
3320     // Ignore method/bci and see if there have been too many globally.
3321     return too_many_traps(reason, md);
3322   }
3323 }
3324 
3325 // Less-accurate variant which does not require a method and bci.
3326 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3327                              ciMethodData* logmd) {
3328   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3329     // Too many traps globally.
3330     // Note that we use cumulative trap_count, not just md->trap_count.
3331     if (log()) {
3332       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3333       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3334                   Deoptimization::trap_reason_name(reason),
3335                   mcount, trap_count(reason));
3336     }
3337     return true;
3338   } else {
3339     // The coast is clear.
3340     return false;
3341   }
3342 }
3343 
3344 //--------------------------too_many_recompiles--------------------------------
3345 // Report if there are too many recompiles at the current method and bci.
3346 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3347 // Is not eager to return true, since this will cause the compiler to use
3348 // Action_none for a trap point, to avoid too many recompilations.
3349 bool Compile::too_many_recompiles(ciMethod* method,
3350                                   int bci,
3351                                   Deoptimization::DeoptReason reason) {
3352   ciMethodData* md = method->method_data();
3353   if (md->is_empty()) {
3354     // Assume the trap has not occurred, or that it occurred only
3355     // because of a transient condition during start-up in the interpreter.
3356     return false;
3357   }
3358   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3359   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3360   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3361   Deoptimization::DeoptReason per_bc_reason
3362     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3363   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3364   if ((per_bc_reason == Deoptimization::Reason_none
3365        || md->has_trap_at(bci, m, reason) != 0)
3366       // The trap frequency measure we care about is the recompile count:
3367       && md->trap_recompiled_at(bci, m)
3368       && md->overflow_recompile_count() >= bc_cutoff) {
3369     // Do not emit a trap here if it has already caused recompilations.
3370     // Also, if there are multiple reasons, or if there is no per-BCI record,
3371     // assume the worst.
3372     if (log())
3373       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3374                   Deoptimization::trap_reason_name(reason),
3375                   md->trap_count(reason),
3376                   md->overflow_recompile_count());
3377     return true;
3378   } else if (trap_count(reason) != 0
3379              && decompile_count() >= m_cutoff) {
3380     // Too many recompiles globally, and we have seen this sort of trap.
3381     // Use cumulative decompile_count, not just md->decompile_count.
3382     if (log())
3383       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3384                   Deoptimization::trap_reason_name(reason),
3385                   md->trap_count(reason), trap_count(reason),
3386                   md->decompile_count(), decompile_count());
3387     return true;
3388   } else {
3389     // The coast is clear.
3390     return false;
3391   }
3392 }
3393 
3394 // Compute when not to trap. Used by matching trap based nodes and
3395 // NullCheck optimization.
3396 void Compile::set_allowed_deopt_reasons() {
3397   _allowed_reasons = 0;
3398   if (is_method_compilation()) {
3399     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3400       assert(rs < BitsPerInt, "recode bit map");
3401       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3402         _allowed_reasons |= nth_bit(rs);
3403       }
3404     }
3405   }
3406 }
3407 
3408 #ifndef PRODUCT
3409 //------------------------------verify_graph_edges---------------------------
3410 // Walk the Graph and verify that there is a one-to-one correspondence
3411 // between Use-Def edges and Def-Use edges in the graph.
3412 void Compile::verify_graph_edges(bool no_dead_code) {
3413   if (VerifyGraphEdges) {
3414     ResourceArea *area = Thread::current()->resource_area();
3415     Unique_Node_List visited(area);
3416     // Call recursive graph walk to check edges
3417     _root->verify_edges(visited);
3418     if (no_dead_code) {
3419       // Now make sure that no visited node is used by an unvisited node.
3420       bool dead_nodes = false;
3421       Unique_Node_List checked(area);
3422       while (visited.size() > 0) {
3423         Node* n = visited.pop();
3424         checked.push(n);
3425         for (uint i = 0; i < n->outcnt(); i++) {
3426           Node* use = n->raw_out(i);
3427           if (checked.member(use))  continue;  // already checked
3428           if (visited.member(use))  continue;  // already in the graph
3429           if (use->is_Con())        continue;  // a dead ConNode is OK
3430           // At this point, we have found a dead node which is DU-reachable.
3431           if (!dead_nodes) {
3432             tty->print_cr("*** Dead nodes reachable via DU edges:");
3433             dead_nodes = true;
3434           }
3435           use->dump(2);
3436           tty->print_cr("---");
3437           checked.push(use);  // No repeats; pretend it is now checked.
3438         }
3439       }
3440       assert(!dead_nodes, "using nodes must be reachable from root");
3441     }
3442   }
3443 }
3444 
3445 // Verify GC barriers consistency
3446 // Currently supported:
3447 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3448 void Compile::verify_barriers() {
3449   if (UseG1GC) {
3450     // Verify G1 pre-barriers
3451     const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3452 
3453     ResourceArea *area = Thread::current()->resource_area();
3454     Unique_Node_List visited(area);
3455     Node_List worklist(area);
3456     // We're going to walk control flow backwards starting from the Root
3457     worklist.push(_root);
3458     while (worklist.size() > 0) {
3459       Node* x = worklist.pop();
3460       if (x == NULL || x == top()) continue;
3461       if (visited.member(x)) {
3462         continue;
3463       } else {
3464         visited.push(x);
3465       }
3466 
3467       if (x->is_Region()) {
3468         for (uint i = 1; i < x->req(); i++) {
3469           worklist.push(x->in(i));
3470         }
3471       } else {
3472         worklist.push(x->in(0));
3473         // We are looking for the pattern:
3474         //                            /->ThreadLocal
3475         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3476         //              \->ConI(0)
3477         // We want to verify that the If and the LoadB have the same control
3478         // See GraphKit::g1_write_barrier_pre()
3479         if (x->is_If()) {
3480           IfNode *iff = x->as_If();
3481           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3482             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3483             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3484                 && cmp->in(1)->is_Load()) {
3485               LoadNode* load = cmp->in(1)->as_Load();
3486               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3487                   && load->in(2)->in(3)->is_Con()
3488                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3489 
3490                 Node* if_ctrl = iff->in(0);
3491                 Node* load_ctrl = load->in(0);
3492 
3493                 if (if_ctrl != load_ctrl) {
3494                   // Skip possible CProj->NeverBranch in infinite loops
3495                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3496                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3497                     if_ctrl = if_ctrl->in(0)->in(0);
3498                   }
3499                 }
3500                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3501               }
3502             }
3503           }
3504         }
3505       }
3506     }
3507   }
3508 }
3509 
3510 #endif
3511 
3512 // The Compile object keeps track of failure reasons separately from the ciEnv.
3513 // This is required because there is not quite a 1-1 relation between the
3514 // ciEnv and its compilation task and the Compile object.  Note that one
3515 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3516 // to backtrack and retry without subsuming loads.  Other than this backtracking
3517 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3518 // by the logic in C2Compiler.
3519 void Compile::record_failure(const char* reason) {
3520   if (log() != NULL) {
3521     log()->elem("failure reason='%s' phase='compile'", reason);
3522   }
3523   if (_failure_reason == NULL) {
3524     // Record the first failure reason.
3525     _failure_reason = reason;
3526   }
3527 
3528   EventCompilerFailure event;
3529   if (event.should_commit()) {
3530     event.set_compileID(Compile::compile_id());
3531     event.set_failure(reason);
3532     event.commit();
3533   }
3534 
3535   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3536     C->print_method(PHASE_FAILURE);
3537   }
3538   _root = NULL;  // flush the graph, too
3539 }
3540 
3541 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3542   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3543     _phase_name(name), _dolog(dolog)
3544 {
3545   if (dolog) {
3546     C = Compile::current();
3547     _log = C->log();
3548   } else {
3549     C = NULL;
3550     _log = NULL;
3551   }
3552   if (_log != NULL) {
3553     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3554     _log->stamp();
3555     _log->end_head();
3556   }
3557 }
3558 
3559 Compile::TracePhase::~TracePhase() {
3560 
3561   C = Compile::current();
3562   if (_dolog) {
3563     _log = C->log();
3564   } else {
3565     _log = NULL;
3566   }
3567 
3568 #ifdef ASSERT
3569   if (PrintIdealNodeCount) {
3570     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3571                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3572   }
3573 
3574   if (VerifyIdealNodeCount) {
3575     Compile::current()->print_missing_nodes();
3576   }
3577 #endif
3578 
3579   if (_log != NULL) {
3580     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3581   }
3582 }
3583 
3584 //=============================================================================
3585 // Two Constant's are equal when the type and the value are equal.
3586 bool Compile::Constant::operator==(const Constant& other) {
3587   if (type()          != other.type()         )  return false;
3588   if (can_be_reused() != other.can_be_reused())  return false;
3589   // For floating point values we compare the bit pattern.
3590   switch (type()) {
3591   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3592   case T_LONG:
3593   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3594   case T_OBJECT:
3595   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3596   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3597   case T_METADATA: return (_v._metadata == other._v._metadata);
3598   default: ShouldNotReachHere();
3599   }
3600   return false;
3601 }
3602 
3603 static int type_to_size_in_bytes(BasicType t) {
3604   switch (t) {
3605   case T_LONG:    return sizeof(jlong  );
3606   case T_FLOAT:   return sizeof(jfloat );
3607   case T_DOUBLE:  return sizeof(jdouble);
3608   case T_METADATA: return sizeof(Metadata*);
3609     // We use T_VOID as marker for jump-table entries (labels) which
3610     // need an internal word relocation.
3611   case T_VOID:
3612   case T_ADDRESS:
3613   case T_OBJECT:  return sizeof(jobject);
3614   }
3615 
3616   ShouldNotReachHere();
3617   return -1;
3618 }
3619 
3620 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3621   // sort descending
3622   if (a->freq() > b->freq())  return -1;
3623   if (a->freq() < b->freq())  return  1;
3624   return 0;
3625 }
3626 
3627 void Compile::ConstantTable::calculate_offsets_and_size() {
3628   // First, sort the array by frequencies.
3629   _constants.sort(qsort_comparator);
3630 
3631 #ifdef ASSERT
3632   // Make sure all jump-table entries were sorted to the end of the
3633   // array (they have a negative frequency).
3634   bool found_void = false;
3635   for (int i = 0; i < _constants.length(); i++) {
3636     Constant con = _constants.at(i);
3637     if (con.type() == T_VOID)
3638       found_void = true;  // jump-tables
3639     else
3640       assert(!found_void, "wrong sorting");
3641   }
3642 #endif
3643 
3644   int offset = 0;
3645   for (int i = 0; i < _constants.length(); i++) {
3646     Constant* con = _constants.adr_at(i);
3647 
3648     // Align offset for type.
3649     int typesize = type_to_size_in_bytes(con->type());
3650     offset = align_size_up(offset, typesize);
3651     con->set_offset(offset);   // set constant's offset
3652 
3653     if (con->type() == T_VOID) {
3654       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3655       offset = offset + typesize * n->outcnt();  // expand jump-table
3656     } else {
3657       offset = offset + typesize;
3658     }
3659   }
3660 
3661   // Align size up to the next section start (which is insts; see
3662   // CodeBuffer::align_at_start).
3663   assert(_size == -1, "already set?");
3664   _size = align_size_up(offset, CodeEntryAlignment);
3665 }
3666 
3667 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3668   MacroAssembler _masm(&cb);
3669   for (int i = 0; i < _constants.length(); i++) {
3670     Constant con = _constants.at(i);
3671     address constant_addr;
3672     switch (con.type()) {
3673     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3674     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3675     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3676     case T_OBJECT: {
3677       jobject obj = con.get_jobject();
3678       int oop_index = _masm.oop_recorder()->find_index(obj);
3679       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3680       break;
3681     }
3682     case T_ADDRESS: {
3683       address addr = (address) con.get_jobject();
3684       constant_addr = _masm.address_constant(addr);
3685       break;
3686     }
3687     // We use T_VOID as marker for jump-table entries (labels) which
3688     // need an internal word relocation.
3689     case T_VOID: {
3690       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3691       // Fill the jump-table with a dummy word.  The real value is
3692       // filled in later in fill_jump_table.
3693       address dummy = (address) n;
3694       constant_addr = _masm.address_constant(dummy);
3695       // Expand jump-table
3696       for (uint i = 1; i < n->outcnt(); i++) {
3697         address temp_addr = _masm.address_constant(dummy + i);
3698         assert(temp_addr, "consts section too small");
3699       }
3700       break;
3701     }
3702     case T_METADATA: {
3703       Metadata* obj = con.get_metadata();
3704       int metadata_index = _masm.oop_recorder()->find_index(obj);
3705       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3706       break;
3707     }
3708     default: ShouldNotReachHere();
3709     }
3710     assert(constant_addr, "consts section too small");
3711     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3712             err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3713   }
3714 }
3715 
3716 int Compile::ConstantTable::find_offset(Constant& con) const {
3717   int idx = _constants.find(con);
3718   assert(idx != -1, "constant must be in constant table");
3719   int offset = _constants.at(idx).offset();
3720   assert(offset != -1, "constant table not emitted yet?");
3721   return offset;
3722 }
3723 
3724 void Compile::ConstantTable::add(Constant& con) {
3725   if (con.can_be_reused()) {
3726     int idx = _constants.find(con);
3727     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3728       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3729       return;
3730     }
3731   }
3732   (void) _constants.append(con);
3733 }
3734 
3735 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3736   Block* b = Compile::current()->cfg()->get_block_for_node(n);
3737   Constant con(type, value, b->_freq);
3738   add(con);
3739   return con;
3740 }
3741 
3742 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3743   Constant con(metadata);
3744   add(con);
3745   return con;
3746 }
3747 
3748 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3749   jvalue value;
3750   BasicType type = oper->type()->basic_type();
3751   switch (type) {
3752   case T_LONG:    value.j = oper->constantL(); break;
3753   case T_FLOAT:   value.f = oper->constantF(); break;
3754   case T_DOUBLE:  value.d = oper->constantD(); break;
3755   case T_OBJECT:
3756   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3757   case T_METADATA: return add((Metadata*)oper->constant()); break;
3758   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3759   }
3760   return add(n, type, value);
3761 }
3762 
3763 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3764   jvalue value;
3765   // We can use the node pointer here to identify the right jump-table
3766   // as this method is called from Compile::Fill_buffer right before
3767   // the MachNodes are emitted and the jump-table is filled (means the
3768   // MachNode pointers do not change anymore).
3769   value.l = (jobject) n;
3770   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3771   add(con);
3772   return con;
3773 }
3774 
3775 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3776   // If called from Compile::scratch_emit_size do nothing.
3777   if (Compile::current()->in_scratch_emit_size())  return;
3778 
3779   assert(labels.is_nonempty(), "must be");
3780   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3781 
3782   // Since MachConstantNode::constant_offset() also contains
3783   // table_base_offset() we need to subtract the table_base_offset()
3784   // to get the plain offset into the constant table.
3785   int offset = n->constant_offset() - table_base_offset();
3786 
3787   MacroAssembler _masm(&cb);
3788   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3789 
3790   for (uint i = 0; i < n->outcnt(); i++) {
3791     address* constant_addr = &jump_table_base[i];
3792     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)));
3793     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3794     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3795   }
3796 }
3797 
3798 // The message about the current inlining is accumulated in
3799 // _print_inlining_stream and transfered into the _print_inlining_list
3800 // once we know whether inlining succeeds or not. For regular
3801 // inlining, messages are appended to the buffer pointed by
3802 // _print_inlining_idx in the _print_inlining_list. For late inlining,
3803 // a new buffer is added after _print_inlining_idx in the list. This
3804 // way we can update the inlining message for late inlining call site
3805 // when the inlining is attempted again.
3806 void Compile::print_inlining_init() {
3807   if (print_inlining() || print_intrinsics()) {
3808     _print_inlining_stream = new stringStream();
3809     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
3810   }
3811 }
3812 
3813 void Compile::print_inlining_reinit() {
3814   if (print_inlining() || print_intrinsics()) {
3815     // Re allocate buffer when we change ResourceMark
3816     _print_inlining_stream = new stringStream();
3817   }
3818 }
3819 
3820 void Compile::print_inlining_reset() {
3821   _print_inlining_stream->reset();
3822 }
3823 
3824 void Compile::print_inlining_commit() {
3825   assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
3826   // Transfer the message from _print_inlining_stream to the current
3827   // _print_inlining_list buffer and clear _print_inlining_stream.
3828   _print_inlining_list->at(_print_inlining_idx).ss()->write(_print_inlining_stream->as_string(), _print_inlining_stream->size());
3829   print_inlining_reset();
3830 }
3831 
3832 void Compile::print_inlining_push() {
3833   // Add new buffer to the _print_inlining_list at current position
3834   _print_inlining_idx++;
3835   _print_inlining_list->insert_before(_print_inlining_idx, PrintInliningBuffer());
3836 }
3837 
3838 Compile::PrintInliningBuffer& Compile::print_inlining_current() {
3839   return _print_inlining_list->at(_print_inlining_idx);
3840 }
3841 
3842 void Compile::print_inlining_update(CallGenerator* cg) {
3843   if (print_inlining() || print_intrinsics()) {
3844     if (!cg->is_late_inline()) {
3845       if (print_inlining_current().cg() != NULL) {
3846         print_inlining_push();
3847       }
3848       print_inlining_commit();
3849     } else {
3850       if (print_inlining_current().cg() != cg &&
3851           (print_inlining_current().cg() != NULL ||
3852            print_inlining_current().ss()->size() != 0)) {
3853         print_inlining_push();
3854       }
3855       print_inlining_commit();
3856       print_inlining_current().set_cg(cg);
3857     }
3858   }
3859 }
3860 
3861 void Compile::print_inlining_move_to(CallGenerator* cg) {
3862   // We resume inlining at a late inlining call site. Locate the
3863   // corresponding inlining buffer so that we can update it.
3864   if (print_inlining()) {
3865     for (int i = 0; i < _print_inlining_list->length(); i++) {
3866       if (_print_inlining_list->adr_at(i)->cg() == cg) {
3867         _print_inlining_idx = i;
3868         return;
3869       }
3870     }
3871     ShouldNotReachHere();
3872   }
3873 }
3874 
3875 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
3876   if (print_inlining()) {
3877     assert(_print_inlining_stream->size() > 0, "missing inlining msg");
3878     assert(print_inlining_current().cg() == cg, "wrong entry");
3879     // replace message with new message
3880     _print_inlining_list->at_put(_print_inlining_idx, PrintInliningBuffer());
3881     print_inlining_commit();
3882     print_inlining_current().set_cg(cg);
3883   }
3884 }
3885 
3886 void Compile::print_inlining_assert_ready() {
3887   assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
3888 }
3889 
3890 void Compile::process_print_inlining() {
3891   bool do_print_inlining = print_inlining() || print_intrinsics();
3892   if (do_print_inlining || log() != NULL) {
3893     // Print inlining message for candidates that we couldn't inline
3894     // for lack of space
3895     for (int i = 0; i < _late_inlines.length(); i++) {
3896       CallGenerator* cg = _late_inlines.at(i);
3897       if (!cg->is_mh_late_inline()) {
3898         const char* msg = "live nodes > LiveNodeCountInliningCutoff";
3899         if (do_print_inlining) {
3900           cg->print_inlining_late(msg);
3901         }
3902         log_late_inline_failure(cg, msg);
3903       }
3904     }
3905   }
3906   if (do_print_inlining) {
3907     ResourceMark rm;
3908     stringStream ss;
3909     for (int i = 0; i < _print_inlining_list->length(); i++) {
3910       ss.print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
3911     }
3912     size_t end = ss.size();
3913     _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
3914     strncpy(_print_inlining_output, ss.base(), end+1);
3915     _print_inlining_output[end] = 0;
3916   }
3917 }
3918 
3919 void Compile::dump_print_inlining() {
3920   if (_print_inlining_output != NULL) {
3921     tty->print_raw(_print_inlining_output);
3922   }
3923 }
3924 
3925 void Compile::log_late_inline(CallGenerator* cg) {
3926   if (log() != NULL) {
3927     log()->head("late_inline method='%d'  inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
3928                 cg->unique_id());
3929     JVMState* p = cg->call_node()->jvms();
3930     while (p != NULL) {
3931       log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
3932       p = p->caller();
3933     }
3934     log()->tail("late_inline");
3935   }
3936 }
3937 
3938 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
3939   log_late_inline(cg);
3940   if (log() != NULL) {
3941     log()->inline_fail(msg);
3942   }
3943 }
3944 
3945 void Compile::log_inline_id(CallGenerator* cg) {
3946   if (log() != NULL) {
3947     // The LogCompilation tool needs a unique way to identify late
3948     // inline call sites. This id must be unique for this call site in
3949     // this compilation. Try to have it unique across compilations as
3950     // well because it can be convenient when grepping through the log
3951     // file.
3952     // Distinguish OSR compilations from others in case CICountOSR is
3953     // on.
3954     jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
3955     cg->set_unique_id(id);
3956     log()->elem("inline_id id='" JLONG_FORMAT "'", id);
3957   }
3958 }
3959 
3960 void Compile::log_inline_failure(const char* msg) {
3961   if (C->log() != NULL) {
3962     C->log()->inline_fail(msg);
3963   }
3964 }
3965 
3966 
3967 // Dump inlining replay data to the stream.
3968 // Don't change thread state and acquire any locks.
3969 void Compile::dump_inline_data(outputStream* out) {
3970   InlineTree* inl_tree = ilt();
3971   if (inl_tree != NULL) {
3972     out->print(" inline %d", inl_tree->count());
3973     inl_tree->dump_replay_data(out);
3974   }
3975 }
3976 
3977 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3978   if (n1->Opcode() < n2->Opcode())      return -1;
3979   else if (n1->Opcode() > n2->Opcode()) return 1;
3980 
3981   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()));
3982   for (uint i = 1; i < n1->req(); i++) {
3983     if (n1->in(i) < n2->in(i))      return -1;
3984     else if (n1->in(i) > n2->in(i)) return 1;
3985   }
3986 
3987   return 0;
3988 }
3989 
3990 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3991   Node* n1 = *n1p;
3992   Node* n2 = *n2p;
3993 
3994   return cmp_expensive_nodes(n1, n2);
3995 }
3996 
3997 void Compile::sort_expensive_nodes() {
3998   if (!expensive_nodes_sorted()) {
3999     _expensive_nodes->sort(cmp_expensive_nodes);
4000   }
4001 }
4002 
4003 bool Compile::expensive_nodes_sorted() const {
4004   for (int i = 1; i < _expensive_nodes->length(); i++) {
4005     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
4006       return false;
4007     }
4008   }
4009   return true;
4010 }
4011 
4012 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
4013   if (_expensive_nodes->length() == 0) {
4014     return false;
4015   }
4016 
4017   assert(OptimizeExpensiveOps, "optimization off?");
4018 
4019   // Take this opportunity to remove dead nodes from the list
4020   int j = 0;
4021   for (int i = 0; i < _expensive_nodes->length(); i++) {
4022     Node* n = _expensive_nodes->at(i);
4023     if (!n->is_unreachable(igvn)) {
4024       assert(n->is_expensive(), "should be expensive");
4025       _expensive_nodes->at_put(j, n);
4026       j++;
4027     }
4028   }
4029   _expensive_nodes->trunc_to(j);
4030 
4031   // Then sort the list so that similar nodes are next to each other
4032   // and check for at least two nodes of identical kind with same data
4033   // inputs.
4034   sort_expensive_nodes();
4035 
4036   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
4037     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
4038       return true;
4039     }
4040   }
4041 
4042   return false;
4043 }
4044 
4045 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4046   if (_expensive_nodes->length() == 0) {
4047     return;
4048   }
4049 
4050   assert(OptimizeExpensiveOps, "optimization off?");
4051 
4052   // Sort to bring similar nodes next to each other and clear the
4053   // control input of nodes for which there's only a single copy.
4054   sort_expensive_nodes();
4055 
4056   int j = 0;
4057   int identical = 0;
4058   int i = 0;
4059   bool modified = false;
4060   for (; i < _expensive_nodes->length()-1; i++) {
4061     assert(j <= i, "can't write beyond current index");
4062     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
4063       identical++;
4064       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4065       continue;
4066     }
4067     if (identical > 0) {
4068       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4069       identical = 0;
4070     } else {
4071       Node* n = _expensive_nodes->at(i);
4072       igvn.replace_input_of(n, 0, NULL);
4073       igvn.hash_insert(n);
4074       modified = true;
4075     }
4076   }
4077   if (identical > 0) {
4078     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4079   } else if (_expensive_nodes->length() >= 1) {
4080     Node* n = _expensive_nodes->at(i);
4081     igvn.replace_input_of(n, 0, NULL);
4082     igvn.hash_insert(n);
4083     modified = true;
4084   }
4085   _expensive_nodes->trunc_to(j);
4086   if (modified) {
4087     igvn.optimize();
4088   }
4089 }
4090 
4091 void Compile::add_expensive_node(Node * n) {
4092   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4093   assert(n->is_expensive(), "expensive nodes with non-null control here only");
4094   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4095   if (OptimizeExpensiveOps) {
4096     _expensive_nodes->append(n);
4097   } else {
4098     // Clear control input and let IGVN optimize expensive nodes if
4099     // OptimizeExpensiveOps is off.
4100     n->set_req(0, NULL);
4101   }
4102 }
4103 
4104 /**
4105  * Remove the speculative part of types and clean up the graph
4106  */
4107 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4108   if (UseTypeSpeculation) {
4109     Unique_Node_List worklist;
4110     worklist.push(root());
4111     int modified = 0;
4112     // Go over all type nodes that carry a speculative type, drop the
4113     // speculative part of the type and enqueue the node for an igvn
4114     // which may optimize it out.
4115     for (uint next = 0; next < worklist.size(); ++next) {
4116       Node *n  = worklist.at(next);
4117       if (n->is_Type()) {
4118         TypeNode* tn = n->as_Type();
4119         const Type* t = tn->type();
4120         const Type* t_no_spec = t->remove_speculative();
4121         if (t_no_spec != t) {
4122           bool in_hash = igvn.hash_delete(n);
4123           assert(in_hash, "node should be in igvn hash table");
4124           tn->set_type(t_no_spec);
4125           igvn.hash_insert(n);
4126           igvn._worklist.push(n); // give it a chance to go away
4127           modified++;
4128         }
4129       }
4130       uint max = n->len();
4131       for( uint i = 0; i < max; ++i ) {
4132         Node *m = n->in(i);
4133         if (not_a_node(m))  continue;
4134         worklist.push(m);
4135       }
4136     }
4137     // Drop the speculative part of all types in the igvn's type table
4138     igvn.remove_speculative_types();
4139     if (modified > 0) {
4140       igvn.optimize();
4141     }
4142 #ifdef ASSERT
4143     // Verify that after the IGVN is over no speculative type has resurfaced
4144     worklist.clear();
4145     worklist.push(root());
4146     for (uint next = 0; next < worklist.size(); ++next) {
4147       Node *n  = worklist.at(next);
4148       const Type* t = igvn.type_or_null(n);
4149       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4150       if (n->is_Type()) {
4151         t = n->as_Type()->type();
4152         assert(t == t->remove_speculative(), "no more speculative types");
4153       }
4154       uint max = n->len();
4155       for( uint i = 0; i < max; ++i ) {
4156         Node *m = n->in(i);
4157         if (not_a_node(m))  continue;
4158         worklist.push(m);
4159       }
4160     }
4161     igvn.check_no_speculative_types();
4162 #endif
4163   }
4164 }
4165 
4166 // Auxiliary method to support randomized stressing/fuzzing.
4167 //
4168 // This method can be called the arbitrary number of times, with current count
4169 // as the argument. The logic allows selecting a single candidate from the
4170 // running list of candidates as follows:
4171 //    int count = 0;
4172 //    Cand* selected = null;
4173 //    while(cand = cand->next()) {
4174 //      if (randomized_select(++count)) {
4175 //        selected = cand;
4176 //      }
4177 //    }
4178 //
4179 // Including count equalizes the chances any candidate is "selected".
4180 // This is useful when we don't have the complete list of candidates to choose
4181 // from uniformly. In this case, we need to adjust the randomicity of the
4182 // selection, or else we will end up biasing the selection towards the latter
4183 // candidates.
4184 //
4185 // Quick back-envelope calculation shows that for the list of n candidates
4186 // the equal probability for the candidate to persist as "best" can be
4187 // achieved by replacing it with "next" k-th candidate with the probability
4188 // of 1/k. It can be easily shown that by the end of the run, the
4189 // probability for any candidate is converged to 1/n, thus giving the
4190 // uniform distribution among all the candidates.
4191 //
4192 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4193 #define RANDOMIZED_DOMAIN_POW 29
4194 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4195 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4196 bool Compile::randomized_select(int count) {
4197   assert(count > 0, "only positive");
4198   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4199 }