1 /*
   2  * Copyright 1997-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 #include "incls/_precompiled.incl"
  26 #include "incls/_parse1.cpp.incl"
  27 
  28 // Static array so we can figure out which bytecodes stop us from compiling
  29 // the most. Some of the non-static variables are needed in bytecodeInfo.cpp
  30 // and eventually should be encapsulated in a proper class (gri 8/18/98).
  31 
  32 int nodes_created              = 0;
  33 int methods_parsed             = 0;
  34 int methods_seen               = 0;
  35 int blocks_parsed              = 0;
  36 int blocks_seen                = 0;
  37 
  38 int explicit_null_checks_inserted = 0;
  39 int explicit_null_checks_elided   = 0;
  40 int all_null_checks_found         = 0, implicit_null_checks              = 0;
  41 int implicit_null_throws          = 0;
  42 
  43 int reclaim_idx  = 0;
  44 int reclaim_in   = 0;
  45 int reclaim_node = 0;
  46 
  47 #ifndef PRODUCT
  48 bool Parse::BytecodeParseHistogram::_initialized = false;
  49 uint Parse::BytecodeParseHistogram::_bytecodes_parsed [Bytecodes::number_of_codes];
  50 uint Parse::BytecodeParseHistogram::_nodes_constructed[Bytecodes::number_of_codes];
  51 uint Parse::BytecodeParseHistogram::_nodes_transformed[Bytecodes::number_of_codes];
  52 uint Parse::BytecodeParseHistogram::_new_values       [Bytecodes::number_of_codes];
  53 #endif
  54 
  55 //------------------------------print_statistics-------------------------------
  56 #ifndef PRODUCT
  57 void Parse::print_statistics() {
  58   tty->print_cr("--- Compiler Statistics ---");
  59   tty->print("Methods seen: %d  Methods parsed: %d", methods_seen, methods_parsed);
  60   tty->print("  Nodes created: %d", nodes_created);
  61   tty->cr();
  62   if (methods_seen != methods_parsed)
  63     tty->print_cr("Reasons for parse failures (NOT cumulative):");
  64   tty->print_cr("Blocks parsed: %d  Blocks seen: %d", blocks_parsed, blocks_seen);
  65 
  66   if( explicit_null_checks_inserted )
  67     tty->print_cr("%d original NULL checks - %d elided (%2d%%); optimizer leaves %d,", explicit_null_checks_inserted, explicit_null_checks_elided, (100*explicit_null_checks_elided)/explicit_null_checks_inserted, all_null_checks_found);
  68   if( all_null_checks_found )
  69     tty->print_cr("%d made implicit (%2d%%)", implicit_null_checks,
  70                   (100*implicit_null_checks)/all_null_checks_found);
  71   if( implicit_null_throws )
  72     tty->print_cr("%d implicit null exceptions at runtime",
  73                   implicit_null_throws);
  74 
  75   if( PrintParseStatistics && BytecodeParseHistogram::initialized() ) {
  76     BytecodeParseHistogram::print();
  77   }
  78 }
  79 #endif
  80 
  81 //------------------------------ON STACK REPLACEMENT---------------------------
  82 
  83 // Construct a node which can be used to get incoming state for
  84 // on stack replacement.
  85 Node *Parse::fetch_interpreter_state(int index,
  86                                      BasicType bt,
  87                                      Node *local_addrs,
  88                                      Node *local_addrs_base) {
  89   Node *mem = memory(Compile::AliasIdxRaw);
  90   Node *adr = basic_plus_adr( local_addrs_base, local_addrs, -index*wordSize );
  91 
  92   // Very similar to LoadNode::make, except we handle un-aligned longs and
  93   // doubles on Sparc.  Intel can handle them just fine directly.
  94   Node *l;
  95   switch( bt ) {                // Signature is flattened
  96   case T_INT:     l = new (C, 3) LoadINode( 0, mem, adr, TypeRawPtr::BOTTOM ); break;
  97   case T_FLOAT:   l = new (C, 3) LoadFNode( 0, mem, adr, TypeRawPtr::BOTTOM ); break;
  98   case T_ADDRESS: l = new (C, 3) LoadPNode( 0, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM  ); break;
  99   case T_OBJECT:  l = new (C, 3) LoadPNode( 0, mem, adr, TypeRawPtr::BOTTOM, TypeInstPtr::BOTTOM ); break;
 100   case T_LONG:
 101   case T_DOUBLE: {
 102     // Since arguments are in reverse order, the argument address 'adr'
 103     // refers to the back half of the long/double.  Recompute adr.
 104     adr = basic_plus_adr( local_addrs_base, local_addrs, -(index+1)*wordSize );
 105     if( Matcher::misaligned_doubles_ok ) {
 106       l = (bt == T_DOUBLE)
 107         ? (Node*)new (C, 3) LoadDNode( 0, mem, adr, TypeRawPtr::BOTTOM )
 108         : (Node*)new (C, 3) LoadLNode( 0, mem, adr, TypeRawPtr::BOTTOM );
 109     } else {
 110       l = (bt == T_DOUBLE)
 111         ? (Node*)new (C, 3) LoadD_unalignedNode( 0, mem, adr, TypeRawPtr::BOTTOM )
 112         : (Node*)new (C, 3) LoadL_unalignedNode( 0, mem, adr, TypeRawPtr::BOTTOM );
 113     }
 114     break;
 115   }
 116   default: ShouldNotReachHere();
 117   }
 118   return _gvn.transform(l);
 119 }
 120 
 121 // Helper routine to prevent the interpreter from handing
 122 // unexpected typestate to an OSR method.
 123 // The Node l is a value newly dug out of the interpreter frame.
 124 // The type is the type predicted by ciTypeFlow.  Note that it is
 125 // not a general type, but can only come from Type::get_typeflow_type.
 126 // The safepoint is a map which will feed an uncommon trap.
 127 Node* Parse::check_interpreter_type(Node* l, const Type* type,
 128                                     SafePointNode* &bad_type_exit) {
 129 
 130   const TypeOopPtr* tp = type->isa_oopptr();
 131 
 132   // TypeFlow may assert null-ness if a type appears unloaded.
 133   if (type == TypePtr::NULL_PTR ||
 134       (tp != NULL && !tp->klass()->is_loaded())) {
 135     // Value must be null, not a real oop.
 136     Node* chk = _gvn.transform( new (C, 3) CmpPNode(l, null()) );
 137     Node* tst = _gvn.transform( new (C, 2) BoolNode(chk, BoolTest::eq) );
 138     IfNode* iff = create_and_map_if(control(), tst, PROB_MAX, COUNT_UNKNOWN);
 139     set_control(_gvn.transform( new (C, 1) IfTrueNode(iff) ));
 140     Node* bad_type = _gvn.transform( new (C, 1) IfFalseNode(iff) );
 141     bad_type_exit->control()->add_req(bad_type);
 142     l = null();
 143   }
 144 
 145   // Typeflow can also cut off paths from the CFG, based on
 146   // types which appear unloaded, or call sites which appear unlinked.
 147   // When paths are cut off, values at later merge points can rise
 148   // toward more specific classes.  Make sure these specific classes
 149   // are still in effect.
 150   if (tp != NULL && tp->klass() != C->env()->Object_klass()) {
 151     // TypeFlow asserted a specific object type.  Value must have that type.
 152     Node* bad_type_ctrl = NULL;
 153     l = gen_checkcast(l, makecon(TypeKlassPtr::make(tp->klass())), &bad_type_ctrl);
 154     bad_type_exit->control()->add_req(bad_type_ctrl);
 155   }
 156 
 157   BasicType bt_l = _gvn.type(l)->basic_type();
 158   BasicType bt_t = type->basic_type();
 159   assert(_gvn.type(l)->higher_equal(type), "must constrain OSR typestate");
 160   return l;
 161 }
 162 
 163 // Helper routine which sets up elements of the initial parser map when
 164 // performing a parse for on stack replacement.  Add values into map.
 165 // The only parameter contains the address of a interpreter arguments.
 166 void Parse::load_interpreter_state(Node* osr_buf) {
 167   int index;
 168   int max_locals = jvms()->loc_size();
 169   int max_stack  = jvms()->stk_size();
 170 
 171 
 172   // Mismatch between method and jvms can occur since map briefly held
 173   // an OSR entry state (which takes up one RawPtr word).
 174   assert(max_locals == method()->max_locals(), "sanity");
 175   assert(max_stack  >= method()->max_stack(),  "sanity");
 176   assert((int)jvms()->endoff() == TypeFunc::Parms + max_locals + max_stack, "sanity");
 177   assert((int)jvms()->endoff() == (int)map()->req(), "sanity");
 178 
 179   // Find the start block.
 180   Block* osr_block = start_block();
 181   assert(osr_block->start() == osr_bci(), "sanity");
 182 
 183   // Set initial BCI.
 184   set_parse_bci(osr_block->start());
 185 
 186   // Set initial stack depth.
 187   set_sp(osr_block->start_sp());
 188 
 189   // Check bailouts.  We currently do not perform on stack replacement
 190   // of loops in catch blocks or loops which branch with a non-empty stack.
 191   if (sp() != 0) {
 192     C->record_method_not_compilable("OSR starts with non-empty stack");
 193     return;
 194   }
 195   // Do not OSR inside finally clauses:
 196   if (osr_block->has_trap_at(osr_block->start())) {
 197     C->record_method_not_compilable("OSR starts with an immediate trap");
 198     return;
 199   }
 200 
 201   // Commute monitors from interpreter frame to compiler frame.
 202   assert(jvms()->monitor_depth() == 0, "should be no active locks at beginning of osr");
 203   int mcnt = osr_block->flow()->monitor_count();
 204   Node *monitors_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals+mcnt*2-1)*wordSize);
 205   for (index = 0; index < mcnt; index++) {
 206     // Make a BoxLockNode for the monitor.
 207     Node *box = _gvn.transform(new (C, 1) BoxLockNode(next_monitor()));
 208 
 209 
 210     // Displaced headers and locked objects are interleaved in the
 211     // temp OSR buffer.  We only copy the locked objects out here.
 212     // Fetch the locked object from the OSR temp buffer and copy to our fastlock node.
 213     Node *lock_object = fetch_interpreter_state(index*2, T_OBJECT, monitors_addr, osr_buf);
 214     // Try and copy the displaced header to the BoxNode
 215     Node *displaced_hdr = fetch_interpreter_state((index*2) + 1, T_ADDRESS, monitors_addr, osr_buf);
 216 
 217 
 218     store_to_memory(control(), box, displaced_hdr, T_ADDRESS, Compile::AliasIdxRaw);
 219 
 220     // Build a bogus FastLockNode (no code will be generated) and push the
 221     // monitor into our debug info.
 222     const FastLockNode *flock = _gvn.transform(new (C, 3) FastLockNode( 0, lock_object, box ))->as_FastLock();
 223     map()->push_monitor(flock);
 224 
 225     // If the lock is our method synchronization lock, tuck it away in
 226     // _sync_lock for return and rethrow exit paths.
 227     if (index == 0 && method()->is_synchronized()) {
 228       _synch_lock = flock;
 229     }
 230   }
 231 
 232   // Use the raw liveness computation to make sure that unexpected
 233   // values don't propagate into the OSR frame.
 234   MethodLivenessResult live_locals = method()->liveness_at_bci(osr_bci());
 235   if (!live_locals.is_valid()) {
 236     // Degenerate or breakpointed method.
 237     C->record_method_not_compilable("OSR in empty or breakpointed method");
 238     return;
 239   }
 240   MethodLivenessResult raw_live_locals = method()->raw_liveness_at_bci(osr_bci());
 241 
 242   // Extract the needed locals from the interpreter frame.
 243   Node *locals_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals-1)*wordSize);
 244 
 245   // find all the locals that the interpreter thinks contain live oops
 246   const BitMap live_oops = method()->live_local_oops_at_bci(osr_bci());
 247   for (index = 0; index < max_locals; index++) {
 248 
 249     if (!live_locals.at(index)) {
 250       continue;
 251     }
 252 
 253     const Type *type = osr_block->local_type_at(index);
 254 
 255     if (type->isa_oopptr() != NULL) {
 256 
 257       // 6403625: Verify that the interpreter oopMap thinks that the oop is live
 258       // else we might load a stale oop if the MethodLiveness disagrees with the
 259       // result of the interpreter. If the interpreter says it is dead we agree
 260       // by making the value go to top.
 261       //
 262 
 263       if (!live_oops.at(index)) {
 264         if (C->log() != NULL) {
 265           C->log()->elem("OSR_mismatch local_index='%d'",index);
 266         }
 267         set_local(index, null());
 268         // and ignore it for the loads
 269         continue;
 270       }
 271     }
 272 
 273     // Filter out TOP, HALF, and BOTTOM.  (Cf. ensure_phi.)
 274     if (type == Type::TOP || type == Type::HALF) {
 275       continue;
 276     }
 277     // If the type falls to bottom, then this must be a local that
 278     // is mixing ints and oops or some such.  Forcing it to top
 279     // makes it go dead.
 280     if (type == Type::BOTTOM) {
 281       continue;
 282     }
 283     // Construct code to access the appropriate local.
 284     Node *value = fetch_interpreter_state(index, type->basic_type(), locals_addr, osr_buf);
 285     set_local(index, value);
 286   }
 287 
 288   // Extract the needed stack entries from the interpreter frame.
 289   for (index = 0; index < sp(); index++) {
 290     const Type *type = osr_block->stack_type_at(index);
 291     if (type != Type::TOP) {
 292       // Currently the compiler bails out when attempting to on stack replace
 293       // at a bci with a non-empty stack.  We should not reach here.
 294       ShouldNotReachHere();
 295     }
 296   }
 297 
 298   // End the OSR migration
 299   make_runtime_call(RC_LEAF, OptoRuntime::osr_end_Type(),
 300                     CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),
 301                     "OSR_migration_end", TypeRawPtr::BOTTOM,
 302                     osr_buf);
 303 
 304   // Now that the interpreter state is loaded, make sure it will match
 305   // at execution time what the compiler is expecting now:
 306   SafePointNode* bad_type_exit = clone_map();
 307   bad_type_exit->set_control(new (C, 1) RegionNode(1));
 308 
 309   for (index = 0; index < max_locals; index++) {
 310     if (stopped())  break;
 311     Node* l = local(index);
 312     if (l->is_top())  continue;  // nothing here
 313     const Type *type = osr_block->local_type_at(index);
 314     if (type->isa_oopptr() != NULL) {
 315       if (!live_oops.at(index)) {
 316         // skip type check for dead oops
 317         continue;
 318       }
 319     }
 320     if (type->basic_type() == T_ADDRESS && !raw_live_locals.at(index)) {
 321       // Skip type check for dead address locals
 322       continue;
 323     }
 324     set_local(index, check_interpreter_type(l, type, bad_type_exit));
 325   }
 326 
 327   for (index = 0; index < sp(); index++) {
 328     if (stopped())  break;
 329     Node* l = stack(index);
 330     if (l->is_top())  continue;  // nothing here
 331     const Type *type = osr_block->stack_type_at(index);
 332     set_stack(index, check_interpreter_type(l, type, bad_type_exit));
 333   }
 334 
 335   if (bad_type_exit->control()->req() > 1) {
 336     // Build an uncommon trap here, if any inputs can be unexpected.
 337     bad_type_exit->set_control(_gvn.transform( bad_type_exit->control() ));
 338     record_for_igvn(bad_type_exit->control());
 339     SafePointNode* types_are_good = map();
 340     set_map(bad_type_exit);
 341     // The unexpected type happens because a new edge is active
 342     // in the CFG, which typeflow had previously ignored.
 343     // E.g., Object x = coldAtFirst() && notReached()? "str": new Integer(123).
 344     // This x will be typed as Integer if notReached is not yet linked.
 345     uncommon_trap(Deoptimization::Reason_unreached,
 346                   Deoptimization::Action_reinterpret);
 347     set_map(types_are_good);
 348   }
 349 }
 350 
 351 //------------------------------Parse------------------------------------------
 352 // Main parser constructor.
 353 Parse::Parse(JVMState* caller, ciMethod* parse_method, float expected_uses)
 354   : _exits(caller)
 355 {
 356   // Init some variables
 357   _caller = caller;
 358   _method = parse_method;
 359   _expected_uses = expected_uses;
 360   _depth = 1 + (caller->has_method() ? caller->depth() : 0);
 361   _wrote_final = false;
 362   _entry_bci = InvocationEntryBci;
 363   _tf = NULL;
 364   _block = NULL;
 365   debug_only(_block_count = -1);
 366   debug_only(_blocks = (Block*)-1);
 367 #ifndef PRODUCT
 368   if (PrintCompilation || PrintOpto) {
 369     // Make sure I have an inline tree, so I can print messages about it.
 370     JVMState* ilt_caller = is_osr_parse() ? caller->caller() : caller;
 371     InlineTree::find_subtree_from_root(C->ilt(), ilt_caller, parse_method, true);
 372   }
 373   _max_switch_depth = 0;
 374   _est_switch_depth = 0;
 375 #endif
 376 
 377   _tf = TypeFunc::make(method());
 378   _iter.reset_to_method(method());
 379   _flow = method()->get_flow_analysis();
 380   if (_flow->failing()) {
 381     C->record_method_not_compilable_all_tiers(_flow->failure_reason());
 382   }
 383 
 384 #ifndef PRODUCT
 385   if (_flow->has_irreducible_entry()) {
 386     C->set_parsed_irreducible_loop(true);
 387   }
 388 #endif
 389 
 390   if (_expected_uses <= 0) {
 391     _prof_factor = 1;
 392   } else {
 393     float prof_total = parse_method->interpreter_invocation_count();
 394     if (prof_total <= _expected_uses) {
 395       _prof_factor = 1;
 396     } else {
 397       _prof_factor = _expected_uses / prof_total;
 398     }
 399   }
 400 
 401   CompileLog* log = C->log();
 402   if (log != NULL) {
 403     log->begin_head("parse method='%d' uses='%g'",
 404                     log->identify(parse_method), expected_uses);
 405     if (depth() == 1 && C->is_osr_compilation()) {
 406       log->print(" osr_bci='%d'", C->entry_bci());
 407     }
 408     log->stamp();
 409     log->end_head();
 410   }
 411 
 412   // Accumulate deoptimization counts.
 413   // (The range_check and store_check counts are checked elsewhere.)
 414   ciMethodData* md = method()->method_data();
 415   for (uint reason = 0; reason < md->trap_reason_limit(); reason++) {
 416     uint md_count = md->trap_count(reason);
 417     if (md_count != 0) {
 418       if (md_count == md->trap_count_limit())
 419         md_count += md->overflow_trap_count();
 420       uint total_count = C->trap_count(reason);
 421       uint old_count   = total_count;
 422       total_count += md_count;
 423       // Saturate the add if it overflows.
 424       if (total_count < old_count || total_count < md_count)
 425         total_count = (uint)-1;
 426       C->set_trap_count(reason, total_count);
 427       if (log != NULL)
 428         log->elem("observe trap='%s' count='%d' total='%d'",
 429                   Deoptimization::trap_reason_name(reason),
 430                   md_count, total_count);
 431     }
 432   }
 433   // Accumulate total sum of decompilations, also.
 434   C->set_decompile_count(C->decompile_count() + md->decompile_count());
 435 
 436   _count_invocations = C->do_count_invocations();
 437   _method_data_update = C->do_method_data_update();
 438 
 439   if (log != NULL && method()->has_exception_handlers()) {
 440     log->elem("observe that='has_exception_handlers'");
 441   }
 442 
 443   assert(method()->can_be_compiled(),       "Can not parse this method, cutout earlier");
 444   assert(method()->has_balanced_monitors(), "Can not parse unbalanced monitors, cutout earlier");
 445 
 446   // Always register dependence if JVMTI is enabled, because
 447   // either breakpoint setting or hotswapping of methods may
 448   // cause deoptimization.
 449   if (C->env()->jvmti_can_hotswap_or_post_breakpoint()) {
 450     C->dependencies()->assert_evol_method(method());
 451   }
 452 
 453   methods_seen++;
 454 
 455   // Do some special top-level things.
 456   if (depth() == 1 && C->is_osr_compilation()) {
 457     _entry_bci = C->entry_bci();
 458     _flow = method()->get_osr_flow_analysis(osr_bci());
 459     if (_flow->failing()) {
 460       C->record_method_not_compilable(_flow->failure_reason());
 461 #ifndef PRODUCT
 462       if (PrintOpto && (Verbose || WizardMode)) {
 463         tty->print_cr("OSR @%d type flow bailout: %s", _entry_bci, _flow->failure_reason());
 464         if (Verbose) {
 465           method()->print_oop();
 466           method()->print_codes();
 467           _flow->print();
 468         }
 469       }
 470 #endif
 471     }
 472     _tf = C->tf();     // the OSR entry type is different
 473   }
 474 
 475 #ifdef ASSERT
 476   if (depth() == 1) {
 477     assert(C->is_osr_compilation() == this->is_osr_parse(), "OSR in sync");
 478     if (C->tf() != tf()) {
 479       MutexLockerEx ml(Compile_lock, Mutex::_no_safepoint_check_flag);
 480       assert(C->env()->system_dictionary_modification_counter_changed(),
 481              "Must invalidate if TypeFuncs differ");
 482     }
 483   } else {
 484     assert(!this->is_osr_parse(), "no recursive OSR");
 485   }
 486 #endif
 487 
 488   methods_parsed++;
 489 #ifndef PRODUCT
 490   // add method size here to guarantee that inlined methods are added too
 491   if (TimeCompiler)
 492     _total_bytes_compiled += method()->code_size();
 493 
 494   show_parse_info();
 495 #endif
 496 
 497   if (failing()) {
 498     if (log)  log->done("parse");
 499     return;
 500   }
 501 
 502   gvn().set_type(root(), root()->bottom_type());
 503   gvn().transform(top());
 504 
 505   // Import the results of the ciTypeFlow.
 506   init_blocks();
 507 
 508   // Merge point for all normal exits
 509   build_exits();
 510 
 511   // Setup the initial JVM state map.
 512   SafePointNode* entry_map = create_entry_map();
 513 
 514   // Check for bailouts during map initialization
 515   if (failing() || entry_map == NULL) {
 516     if (log)  log->done("parse");
 517     return;
 518   }
 519 
 520   Node_Notes* caller_nn = C->default_node_notes();
 521   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
 522   if (DebugInlinedCalls || depth() == 1) {
 523     C->set_default_node_notes(make_node_notes(caller_nn));
 524   }
 525 
 526   if (is_osr_parse()) {
 527     Node* osr_buf = entry_map->in(TypeFunc::Parms+0);
 528     entry_map->set_req(TypeFunc::Parms+0, top());
 529     set_map(entry_map);
 530     load_interpreter_state(osr_buf);
 531   } else {
 532     set_map(entry_map);
 533     do_method_entry();
 534   }
 535 
 536   // Check for bailouts during method entry.
 537   if (failing()) {
 538     if (log)  log->done("parse");
 539     C->set_default_node_notes(caller_nn);
 540     return;
 541   }
 542 
 543   entry_map = map();  // capture any changes performed by method setup code
 544   assert(jvms()->endoff() == map()->req(), "map matches JVMS layout");
 545 
 546   // We begin parsing as if we have just encountered a jump to the
 547   // method entry.
 548   Block* entry_block = start_block();
 549   assert(entry_block->start() == (is_osr_parse() ? osr_bci() : 0), "");
 550   set_map_clone(entry_map);
 551   merge_common(entry_block, entry_block->next_path_num());
 552 
 553 #ifndef PRODUCT
 554   BytecodeParseHistogram *parse_histogram_obj = new (C->env()->arena()) BytecodeParseHistogram(this, C);
 555   set_parse_histogram( parse_histogram_obj );
 556 #endif
 557 
 558   // Parse all the basic blocks.
 559   do_all_blocks();
 560 
 561   C->set_default_node_notes(caller_nn);
 562 
 563   // Check for bailouts during conversion to graph
 564   if (failing()) {
 565     if (log)  log->done("parse");
 566     return;
 567   }
 568 
 569   // Fix up all exiting control flow.
 570   set_map(entry_map);
 571   do_exits();
 572 
 573   if (log)  log->done("parse nodes='%d' memory='%d'",
 574                       C->unique(), C->node_arena()->used());
 575 }
 576 
 577 //---------------------------do_all_blocks-------------------------------------
 578 void Parse::do_all_blocks() {
 579   bool has_irreducible = flow()->has_irreducible_entry();
 580 
 581   // Walk over all blocks in Reverse Post-Order.
 582   while (true) {
 583     bool progress = false;
 584     for (int rpo = 0; rpo < block_count(); rpo++) {
 585       Block* block = rpo_at(rpo);
 586 
 587       if (block->is_parsed()) continue;
 588 
 589       if (!block->is_merged()) {
 590         // Dead block, no state reaches this block
 591         continue;
 592       }
 593 
 594       // Prepare to parse this block.
 595       load_state_from(block);
 596 
 597       if (stopped()) {
 598         // Block is dead.
 599         continue;
 600       }
 601 
 602       blocks_parsed++;
 603 
 604       progress = true;
 605       if (block->is_loop_head() || block->is_handler() || has_irreducible && !block->is_ready()) {
 606         // Not all preds have been parsed.  We must build phis everywhere.
 607         // (Note that dead locals do not get phis built, ever.)
 608         ensure_phis_everywhere();
 609 
 610         // Leave behind an undisturbed copy of the map, for future merges.
 611         set_map(clone_map());
 612       }
 613 
 614       if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) {
 615         // In the absence of irreducible loops, the Region and Phis
 616         // associated with a merge that doesn't involve a backedge can
 617         // be simplified now since the RPO parsing order guarantees
 618         // that any path which was supposed to reach here has already
 619         // been parsed or must be dead.
 620         Node* c = control();
 621         Node* result = _gvn.transform_no_reclaim(control());
 622         if (c != result && TraceOptoParse) {
 623           tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx);
 624         }
 625         if (result != top()) {
 626           record_for_igvn(result);
 627         }
 628       }
 629 
 630       // Parse the block.
 631       do_one_block();
 632 
 633       // Check for bailouts.
 634       if (failing())  return;
 635     }
 636 
 637     // with irreducible loops multiple passes might be necessary to parse everything
 638     if (!has_irreducible || !progress) {
 639       break;
 640     }
 641   }
 642 
 643   blocks_seen += block_count();
 644 
 645 #ifndef PRODUCT
 646   // Make sure there are no half-processed blocks remaining.
 647   // Every remaining unprocessed block is dead and may be ignored now.
 648   for (int rpo = 0; rpo < block_count(); rpo++) {
 649     Block* block = rpo_at(rpo);
 650     if (!block->is_parsed()) {
 651       if (TraceOptoParse) {
 652         tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start());
 653       }
 654       assert(!block->is_merged(), "no half-processed blocks");
 655     }
 656   }
 657 #endif
 658 }
 659 
 660 //-------------------------------build_exits----------------------------------
 661 // Build normal and exceptional exit merge points.
 662 void Parse::build_exits() {
 663   // make a clone of caller to prevent sharing of side-effects
 664   _exits.set_map(_exits.clone_map());
 665   _exits.clean_stack(_exits.sp());
 666   _exits.sync_jvms();
 667 
 668   RegionNode* region = new (C, 1) RegionNode(1);
 669   record_for_igvn(region);
 670   gvn().set_type_bottom(region);
 671   _exits.set_control(region);
 672 
 673   // Note:  iophi and memphi are not transformed until do_exits.
 674   Node* iophi  = new (C, region->req()) PhiNode(region, Type::ABIO);
 675   Node* memphi = new (C, region->req()) PhiNode(region, Type::MEMORY, TypePtr::BOTTOM);
 676   _exits.set_i_o(iophi);
 677   _exits.set_all_memory(memphi);
 678 
 679   // Add a return value to the exit state.  (Do not push it yet.)
 680   if (tf()->range()->cnt() > TypeFunc::Parms) {
 681     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
 682     // Don't "bind" an unloaded return klass to the ret_phi. If the klass
 683     // becomes loaded during the subsequent parsing, the loaded and unloaded
 684     // types will not join when we transform and push in do_exits().
 685     const TypeOopPtr* ret_oop_type = ret_type->isa_oopptr();
 686     if (ret_oop_type && !ret_oop_type->klass()->is_loaded()) {
 687       ret_type = TypeOopPtr::BOTTOM;
 688     }
 689     int         ret_size = type2size[ret_type->basic_type()];
 690     Node*       ret_phi  = new (C, region->req()) PhiNode(region, ret_type);
 691     _exits.ensure_stack(ret_size);
 692     assert((int)(tf()->range()->cnt() - TypeFunc::Parms) == ret_size, "good tf range");
 693     assert(method()->return_type()->size() == ret_size, "tf agrees w/ method");
 694     _exits.set_argument(0, ret_phi);  // here is where the parser finds it
 695     // Note:  ret_phi is not yet pushed, until do_exits.
 696   }
 697 }
 698 
 699 
 700 //----------------------------build_start_state-------------------------------
 701 // Construct a state which contains only the incoming arguments from an
 702 // unknown caller.  The method & bci will be NULL & InvocationEntryBci.
 703 JVMState* Compile::build_start_state(StartNode* start, const TypeFunc* tf) {
 704   int        arg_size = tf->domain()->cnt();
 705   int        max_size = MAX2(arg_size, (int)tf->range()->cnt());
 706   JVMState*  jvms     = new (this) JVMState(max_size - TypeFunc::Parms);
 707   SafePointNode* map  = new (this, max_size) SafePointNode(max_size, NULL);
 708   record_for_igvn(map);
 709   assert(arg_size == TypeFunc::Parms + (is_osr_compilation() ? 1 : method()->arg_size()), "correct arg_size");
 710   Node_Notes* old_nn = default_node_notes();
 711   if (old_nn != NULL && has_method()) {
 712     Node_Notes* entry_nn = old_nn->clone(this);
 713     JVMState* entry_jvms = new(this) JVMState(method(), old_nn->jvms());
 714     entry_jvms->set_offsets(0);
 715     entry_jvms->set_bci(entry_bci());
 716     entry_nn->set_jvms(entry_jvms);
 717     set_default_node_notes(entry_nn);
 718   }
 719   uint i;
 720   for (i = 0; i < (uint)arg_size; i++) {
 721     Node* parm = initial_gvn()->transform(new (this, 1) ParmNode(start, i));
 722     map->init_req(i, parm);
 723     // Record all these guys for later GVN.
 724     record_for_igvn(parm);
 725   }
 726   for (; i < map->req(); i++) {
 727     map->init_req(i, top());
 728   }
 729   assert(jvms->argoff() == TypeFunc::Parms, "parser gets arguments here");
 730   set_default_node_notes(old_nn);
 731   map->set_jvms(jvms);
 732   jvms->set_map(map);
 733   return jvms;
 734 }
 735 
 736 //-----------------------------make_node_notes---------------------------------
 737 Node_Notes* Parse::make_node_notes(Node_Notes* caller_nn) {
 738   if (caller_nn == NULL)  return NULL;
 739   Node_Notes* nn = caller_nn->clone(C);
 740   JVMState* caller_jvms = nn->jvms();
 741   JVMState* jvms = new (C) JVMState(method(), caller_jvms);
 742   jvms->set_offsets(0);
 743   jvms->set_bci(_entry_bci);
 744   nn->set_jvms(jvms);
 745   return nn;
 746 }
 747 
 748 
 749 //--------------------------return_values--------------------------------------
 750 void Compile::return_values(JVMState* jvms) {
 751   GraphKit kit(jvms);
 752   Node* ret = new (this, TypeFunc::Parms) ReturnNode(TypeFunc::Parms,
 753                              kit.control(),
 754                              kit.i_o(),
 755                              kit.reset_memory(),
 756                              kit.frameptr(),
 757                              kit.returnadr());
 758   // Add zero or 1 return values
 759   int ret_size = tf()->range()->cnt() - TypeFunc::Parms;
 760   if (ret_size > 0) {
 761     kit.inc_sp(-ret_size);  // pop the return value(s)
 762     kit.sync_jvms();
 763     ret->add_req(kit.argument(0));
 764     // Note:  The second dummy edge is not needed by a ReturnNode.
 765   }
 766   // bind it to root
 767   root()->add_req(ret);
 768   record_for_igvn(ret);
 769   initial_gvn()->transform_no_reclaim(ret);
 770 }
 771 
 772 //------------------------rethrow_exceptions-----------------------------------
 773 // Bind all exception states in the list into a single RethrowNode.
 774 void Compile::rethrow_exceptions(JVMState* jvms) {
 775   GraphKit kit(jvms);
 776   if (!kit.has_exceptions())  return;  // nothing to generate
 777   // Load my combined exception state into the kit, with all phis transformed:
 778   SafePointNode* ex_map = kit.combine_and_pop_all_exception_states();
 779   Node* ex_oop = kit.use_exception_state(ex_map);
 780   RethrowNode* exit = new (this, TypeFunc::Parms + 1) RethrowNode(kit.control(),
 781                                       kit.i_o(), kit.reset_memory(),
 782                                       kit.frameptr(), kit.returnadr(),
 783                                       // like a return but with exception input
 784                                       ex_oop);
 785   // bind to root
 786   root()->add_req(exit);
 787   record_for_igvn(exit);
 788   initial_gvn()->transform_no_reclaim(exit);
 789 }
 790 
 791 bool Parse::can_rerun_bytecode() {
 792   switch (bc()) {
 793   case Bytecodes::_ldc:
 794   case Bytecodes::_ldc_w:
 795   case Bytecodes::_ldc2_w:
 796   case Bytecodes::_getfield:
 797   case Bytecodes::_putfield:
 798   case Bytecodes::_getstatic:
 799   case Bytecodes::_putstatic:
 800   case Bytecodes::_arraylength:
 801   case Bytecodes::_baload:
 802   case Bytecodes::_caload:
 803   case Bytecodes::_iaload:
 804   case Bytecodes::_saload:
 805   case Bytecodes::_faload:
 806   case Bytecodes::_aaload:
 807   case Bytecodes::_laload:
 808   case Bytecodes::_daload:
 809   case Bytecodes::_bastore:
 810   case Bytecodes::_castore:
 811   case Bytecodes::_iastore:
 812   case Bytecodes::_sastore:
 813   case Bytecodes::_fastore:
 814   case Bytecodes::_aastore:
 815   case Bytecodes::_lastore:
 816   case Bytecodes::_dastore:
 817   case Bytecodes::_irem:
 818   case Bytecodes::_idiv:
 819   case Bytecodes::_lrem:
 820   case Bytecodes::_ldiv:
 821   case Bytecodes::_frem:
 822   case Bytecodes::_fdiv:
 823   case Bytecodes::_drem:
 824   case Bytecodes::_ddiv:
 825   case Bytecodes::_checkcast:
 826   case Bytecodes::_instanceof:
 827   case Bytecodes::_anewarray:
 828   case Bytecodes::_newarray:
 829   case Bytecodes::_multianewarray:
 830   case Bytecodes::_new:
 831   case Bytecodes::_monitorenter:  // can re-run initial null check, only
 832   case Bytecodes::_return:
 833     return true;
 834     break;
 835 
 836   // Don't rerun athrow since it's part of the exception path.
 837   case Bytecodes::_athrow:
 838   case Bytecodes::_invokestatic:
 839   case Bytecodes::_invokedynamic:
 840   case Bytecodes::_invokespecial:
 841   case Bytecodes::_invokevirtual:
 842   case Bytecodes::_invokeinterface:
 843     return false;
 844     break;
 845 
 846   default:
 847     assert(false, "unexpected bytecode produced an exception");
 848     return true;
 849   }
 850 }
 851 
 852 //---------------------------do_exceptions-------------------------------------
 853 // Process exceptions arising from the current bytecode.
 854 // Send caught exceptions to the proper handler within this method.
 855 // Unhandled exceptions feed into _exit.
 856 void Parse::do_exceptions() {
 857   if (!has_exceptions())  return;
 858 
 859   if (failing()) {
 860     // Pop them all off and throw them away.
 861     while (pop_exception_state() != NULL) ;
 862     return;
 863   }
 864 
 865   // Make sure we can classify this bytecode if we need to.
 866   debug_only(can_rerun_bytecode());
 867 
 868   PreserveJVMState pjvms(this, false);
 869 
 870   SafePointNode* ex_map;
 871   while ((ex_map = pop_exception_state()) != NULL) {
 872     if (!method()->has_exception_handlers()) {
 873       // Common case:  Transfer control outward.
 874       // Doing it this early allows the exceptions to common up
 875       // even between adjacent method calls.
 876       throw_to_exit(ex_map);
 877     } else {
 878       // Have to look at the exception first.
 879       assert(stopped(), "catch_inline_exceptions trashes the map");
 880       catch_inline_exceptions(ex_map);
 881       stop_and_kill_map();      // we used up this exception state; kill it
 882     }
 883   }
 884 
 885   // We now return to our regularly scheduled program:
 886 }
 887 
 888 //---------------------------throw_to_exit-------------------------------------
 889 // Merge the given map into an exception exit from this method.
 890 // The exception exit will handle any unlocking of receiver.
 891 // The ex_oop must be saved within the ex_map, unlike merge_exception.
 892 void Parse::throw_to_exit(SafePointNode* ex_map) {
 893   // Pop the JVMS to (a copy of) the caller.
 894   GraphKit caller;
 895   caller.set_map_clone(_caller->map());
 896   caller.set_bci(_caller->bci());
 897   caller.set_sp(_caller->sp());
 898   // Copy out the standard machine state:
 899   for (uint i = 0; i < TypeFunc::Parms; i++) {
 900     caller.map()->set_req(i, ex_map->in(i));
 901   }
 902   // ...and the exception:
 903   Node*          ex_oop        = saved_ex_oop(ex_map);
 904   SafePointNode* caller_ex_map = caller.make_exception_state(ex_oop);
 905   // Finally, collect the new exception state in my exits:
 906   _exits.add_exception_state(caller_ex_map);
 907 }
 908 
 909 //------------------------------do_exits---------------------------------------
 910 void Parse::do_exits() {
 911   set_parse_bci(InvocationEntryBci);
 912 
 913   // Now peephole on the return bits
 914   Node* region = _exits.control();
 915   _exits.set_control(gvn().transform(region));
 916 
 917   Node* iophi = _exits.i_o();
 918   _exits.set_i_o(gvn().transform(iophi));
 919 
 920   if (wrote_final()) {
 921     // This method (which must be a constructor by the rules of Java)
 922     // wrote a final.  The effects of all initializations must be
 923     // committed to memory before any code after the constructor
 924     // publishes the reference to the newly constructor object.
 925     // Rather than wait for the publication, we simply block the
 926     // writes here.  Rather than put a barrier on only those writes
 927     // which are required to complete, we force all writes to complete.
 928     //
 929     // "All bets are off" unless the first publication occurs after a
 930     // normal return from the constructor.  We do not attempt to detect
 931     // such unusual early publications.  But no barrier is needed on
 932     // exceptional returns, since they cannot publish normally.
 933     //
 934     _exits.insert_mem_bar(Op_MemBarRelease);
 935 #ifndef PRODUCT
 936     if (PrintOpto && (Verbose || WizardMode)) {
 937       method()->print_name();
 938       tty->print_cr(" writes finals and needs a memory barrier");
 939     }
 940 #endif
 941   }
 942 
 943   for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) {
 944     // transform each slice of the original memphi:
 945     mms.set_memory(_gvn.transform(mms.memory()));
 946   }
 947 
 948   if (tf()->range()->cnt() > TypeFunc::Parms) {
 949     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
 950     Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
 951     assert(_exits.control()->is_top() || !_gvn.type(ret_phi)->empty(), "return value must be well defined");
 952     _exits.push_node(ret_type->basic_type(), ret_phi);
 953   }
 954 
 955   // Note:  Logic for creating and optimizing the ReturnNode is in Compile.
 956 
 957   // Unlock along the exceptional paths.
 958   // This is done late so that we can common up equivalent exceptions
 959   // (e.g., null checks) arising from multiple points within this method.
 960   // See GraphKit::add_exception_state, which performs the commoning.
 961   bool do_synch = method()->is_synchronized() && GenerateSynchronizationCode;
 962 
 963   // record exit from a method if compiled while Dtrace is turned on.
 964   if (do_synch || C->env()->dtrace_method_probes()) {
 965     // First move the exception list out of _exits:
 966     GraphKit kit(_exits.transfer_exceptions_into_jvms());
 967     SafePointNode* normal_map = kit.map();  // keep this guy safe
 968     // Now re-collect the exceptions into _exits:
 969     SafePointNode* ex_map;
 970     while ((ex_map = kit.pop_exception_state()) != NULL) {
 971       Node* ex_oop = kit.use_exception_state(ex_map);
 972       // Force the exiting JVM state to have this method at InvocationEntryBci.
 973       // The exiting JVM state is otherwise a copy of the calling JVMS.
 974       JVMState* caller = kit.jvms();
 975       JVMState* ex_jvms = caller->clone_shallow(C);
 976       ex_jvms->set_map(kit.clone_map());
 977       ex_jvms->map()->set_jvms(ex_jvms);
 978       ex_jvms->set_bci(   InvocationEntryBci);
 979       kit.set_jvms(ex_jvms);
 980       if (do_synch) {
 981         // Add on the synchronized-method box/object combo
 982         kit.map()->push_monitor(_synch_lock);
 983         // Unlock!
 984         kit.shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
 985       }
 986       if (C->env()->dtrace_method_probes()) {
 987         kit.make_dtrace_method_exit(method());
 988       }
 989       // Done with exception-path processing.
 990       ex_map = kit.make_exception_state(ex_oop);
 991       assert(ex_jvms->same_calls_as(ex_map->jvms()), "sanity");
 992       // Pop the last vestige of this method:
 993       ex_map->set_jvms(caller->clone_shallow(C));
 994       ex_map->jvms()->set_map(ex_map);
 995       _exits.push_exception_state(ex_map);
 996     }
 997     assert(_exits.map() == normal_map, "keep the same return state");
 998   }
 999 
1000   {
1001     // Capture very early exceptions (receiver null checks) from caller JVMS
1002     GraphKit caller(_caller);
1003     SafePointNode* ex_map;
1004     while ((ex_map = caller.pop_exception_state()) != NULL) {
1005       _exits.add_exception_state(ex_map);
1006     }
1007   }
1008 }
1009 
1010 //-----------------------------create_entry_map-------------------------------
1011 // Initialize our parser map to contain the types at method entry.
1012 // For OSR, the map contains a single RawPtr parameter.
1013 // Initial monitor locking for sync. methods is performed by do_method_entry.
1014 SafePointNode* Parse::create_entry_map() {
1015   // Check for really stupid bail-out cases.
1016   uint len = TypeFunc::Parms + method()->max_locals() + method()->max_stack();
1017   if (len >= 32760) {
1018     C->record_method_not_compilable_all_tiers("too many local variables");
1019     return NULL;
1020   }
1021 
1022   // If this is an inlined method, we may have to do a receiver null check.
1023   if (_caller->has_method() && is_normal_parse() && !method()->is_static()) {
1024     GraphKit kit(_caller);
1025     kit.null_check_receiver(method());
1026     _caller = kit.transfer_exceptions_into_jvms();
1027     if (kit.stopped()) {
1028       _exits.add_exception_states_from(_caller);
1029       _exits.set_jvms(_caller);
1030       return NULL;
1031     }
1032   }
1033 
1034   assert(method() != NULL, "parser must have a method");
1035 
1036   // Create an initial safepoint to hold JVM state during parsing
1037   JVMState* jvms = new (C) JVMState(method(), _caller->has_method() ? _caller : NULL);
1038   set_map(new (C, len) SafePointNode(len, jvms));
1039   jvms->set_map(map());
1040   record_for_igvn(map());
1041   assert(jvms->endoff() == len, "correct jvms sizing");
1042 
1043   SafePointNode* inmap = _caller->map();
1044   assert(inmap != NULL, "must have inmap");
1045 
1046   uint i;
1047 
1048   // Pass thru the predefined input parameters.
1049   for (i = 0; i < TypeFunc::Parms; i++) {
1050     map()->init_req(i, inmap->in(i));
1051   }
1052 
1053   if (depth() == 1) {
1054     assert(map()->memory()->Opcode() == Op_Parm, "");
1055     // Insert the memory aliasing node
1056     set_all_memory(reset_memory());
1057   }
1058   assert(merged_memory(), "");
1059 
1060   // Now add the locals which are initially bound to arguments:
1061   uint arg_size = tf()->domain()->cnt();
1062   ensure_stack(arg_size - TypeFunc::Parms);  // OSR methods have funny args
1063   for (i = TypeFunc::Parms; i < arg_size; i++) {
1064     map()->init_req(i, inmap->argument(_caller, i - TypeFunc::Parms));
1065   }
1066 
1067   // Clear out the rest of the map (locals and stack)
1068   for (i = arg_size; i < len; i++) {
1069     map()->init_req(i, top());
1070   }
1071 
1072   SafePointNode* entry_map = stop();
1073   return entry_map;
1074 }
1075 
1076 //-----------------------------do_method_entry--------------------------------
1077 // Emit any code needed in the pseudo-block before BCI zero.
1078 // The main thing to do is lock the receiver of a synchronized method.
1079 void Parse::do_method_entry() {
1080   set_parse_bci(InvocationEntryBci); // Pseudo-BCP
1081   set_sp(0);                      // Java Stack Pointer
1082 
1083   NOT_PRODUCT( count_compiled_calls(true/*at_method_entry*/, false/*is_inline*/); )
1084 
1085   if (C->env()->dtrace_method_probes()) {
1086     make_dtrace_method_entry(method());
1087   }
1088 
1089   // If the method is synchronized, we need to construct a lock node, attach
1090   // it to the Start node, and pin it there.
1091   if (method()->is_synchronized()) {
1092     // Insert a FastLockNode right after the Start which takes as arguments
1093     // the current thread pointer, the "this" pointer & the address of the
1094     // stack slot pair used for the lock.  The "this" pointer is a projection
1095     // off the start node, but the locking spot has to be constructed by
1096     // creating a ConLNode of 0, and boxing it with a BoxLockNode.  The BoxLockNode
1097     // becomes the second argument to the FastLockNode call.  The
1098     // FastLockNode becomes the new control parent to pin it to the start.
1099 
1100     // Setup Object Pointer
1101     Node *lock_obj = NULL;
1102     if(method()->is_static()) {
1103       ciInstance* mirror = _method->holder()->java_mirror();
1104       const TypeInstPtr *t_lock = TypeInstPtr::make(mirror);
1105       lock_obj = makecon(t_lock);
1106     } else {                  // Else pass the "this" pointer,
1107       lock_obj = local(0);    // which is Parm0 from StartNode
1108     }
1109     // Clear out dead values from the debug info.
1110     kill_dead_locals();
1111     // Build the FastLockNode
1112     _synch_lock = shared_lock(lock_obj);
1113   }
1114 
1115   if (depth() == 1) {
1116     increment_and_test_invocation_counter(Tier2CompileThreshold);
1117   }
1118 }
1119 
1120 //------------------------------init_blocks------------------------------------
1121 // Initialize our parser map to contain the types/monitors at method entry.
1122 void Parse::init_blocks() {
1123   // Create the blocks.
1124   _block_count = flow()->block_count();
1125   _blocks = NEW_RESOURCE_ARRAY(Block, _block_count);
1126   Copy::zero_to_bytes(_blocks, sizeof(Block)*_block_count);
1127 
1128   int rpo;
1129 
1130   // Initialize the structs.
1131   for (rpo = 0; rpo < block_count(); rpo++) {
1132     Block* block = rpo_at(rpo);
1133     block->init_node(this, rpo);
1134   }
1135 
1136   // Collect predecessor and successor information.
1137   for (rpo = 0; rpo < block_count(); rpo++) {
1138     Block* block = rpo_at(rpo);
1139     block->init_graph(this);
1140   }
1141 }
1142 
1143 //-------------------------------init_node-------------------------------------
1144 void Parse::Block::init_node(Parse* outer, int rpo) {
1145   _flow = outer->flow()->rpo_at(rpo);
1146   _pred_count = 0;
1147   _preds_parsed = 0;
1148   _count = 0;
1149   assert(pred_count() == 0 && preds_parsed() == 0, "sanity");
1150   assert(!(is_merged() || is_parsed() || is_handler()), "sanity");
1151   assert(_live_locals.size() == 0, "sanity");
1152 
1153   // entry point has additional predecessor
1154   if (flow()->is_start())  _pred_count++;
1155   assert(flow()->is_start() == (this == outer->start_block()), "");
1156 }
1157 
1158 //-------------------------------init_graph------------------------------------
1159 void Parse::Block::init_graph(Parse* outer) {
1160   // Create the successor list for this parser block.
1161   GrowableArray<ciTypeFlow::Block*>* tfs = flow()->successors();
1162   GrowableArray<ciTypeFlow::Block*>* tfe = flow()->exceptions();
1163   int ns = tfs->length();
1164   int ne = tfe->length();
1165   _num_successors = ns;
1166   _all_successors = ns+ne;
1167   _successors = (ns+ne == 0) ? NULL : NEW_RESOURCE_ARRAY(Block*, ns+ne);
1168   int p = 0;
1169   for (int i = 0; i < ns+ne; i++) {
1170     ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns);
1171     Block* block2 = outer->rpo_at(tf2->rpo());
1172     _successors[i] = block2;
1173 
1174     // Accumulate pred info for the other block, too.
1175     if (i < ns) {
1176       block2->_pred_count++;
1177     } else {
1178       block2->_is_handler = true;
1179     }
1180 
1181     #ifdef ASSERT
1182     // A block's successors must be distinguishable by BCI.
1183     // That is, no bytecode is allowed to branch to two different
1184     // clones of the same code location.
1185     for (int j = 0; j < i; j++) {
1186       Block* block1 = _successors[j];
1187       if (block1 == block2)  continue;  // duplicates are OK
1188       assert(block1->start() != block2->start(), "successors have unique bcis");
1189     }
1190     #endif
1191   }
1192 
1193   // Note: We never call next_path_num along exception paths, so they
1194   // never get processed as "ready".  Also, the input phis of exception
1195   // handlers get specially processed, so that
1196 }
1197 
1198 //---------------------------successor_for_bci---------------------------------
1199 Parse::Block* Parse::Block::successor_for_bci(int bci) {
1200   for (int i = 0; i < all_successors(); i++) {
1201     Block* block2 = successor_at(i);
1202     if (block2->start() == bci)  return block2;
1203   }
1204   // We can actually reach here if ciTypeFlow traps out a block
1205   // due to an unloaded class, and concurrently with compilation the
1206   // class is then loaded, so that a later phase of the parser is
1207   // able to see more of the bytecode CFG.  Or, the flow pass and
1208   // the parser can have a minor difference of opinion about executability
1209   // of bytecodes.  For example, "obj.field = null" is executable even
1210   // if the field's type is an unloaded class; the flow pass used to
1211   // make a trap for such code.
1212   return NULL;
1213 }
1214 
1215 
1216 //-----------------------------stack_type_at-----------------------------------
1217 const Type* Parse::Block::stack_type_at(int i) const {
1218   return get_type(flow()->stack_type_at(i));
1219 }
1220 
1221 
1222 //-----------------------------local_type_at-----------------------------------
1223 const Type* Parse::Block::local_type_at(int i) const {
1224   // Make dead locals fall to bottom.
1225   if (_live_locals.size() == 0) {
1226     MethodLivenessResult live_locals = flow()->outer()->method()->liveness_at_bci(start());
1227     // This bitmap can be zero length if we saw a breakpoint.
1228     // In such cases, pretend they are all live.
1229     ((Block*)this)->_live_locals = live_locals;
1230   }
1231   if (_live_locals.size() > 0 && !_live_locals.at(i))
1232     return Type::BOTTOM;
1233 
1234   return get_type(flow()->local_type_at(i));
1235 }
1236 
1237 
1238 #ifndef PRODUCT
1239 
1240 //----------------------------name_for_bc--------------------------------------
1241 // helper method for BytecodeParseHistogram
1242 static const char* name_for_bc(int i) {
1243   return Bytecodes::is_defined(i) ? Bytecodes::name(Bytecodes::cast(i)) : "xxxunusedxxx";
1244 }
1245 
1246 //----------------------------BytecodeParseHistogram------------------------------------
1247 Parse::BytecodeParseHistogram::BytecodeParseHistogram(Parse *p, Compile *c) {
1248   _parser   = p;
1249   _compiler = c;
1250   if( ! _initialized ) { _initialized = true; reset(); }
1251 }
1252 
1253 //----------------------------current_count------------------------------------
1254 int Parse::BytecodeParseHistogram::current_count(BPHType bph_type) {
1255   switch( bph_type ) {
1256   case BPH_transforms: { return _parser->gvn().made_progress(); }
1257   case BPH_values:     { return _parser->gvn().made_new_values(); }
1258   default: { ShouldNotReachHere(); return 0; }
1259   }
1260 }
1261 
1262 //----------------------------initialized--------------------------------------
1263 bool Parse::BytecodeParseHistogram::initialized() { return _initialized; }
1264 
1265 //----------------------------reset--------------------------------------------
1266 void Parse::BytecodeParseHistogram::reset() {
1267   int i = Bytecodes::number_of_codes;
1268   while (i-- > 0) { _bytecodes_parsed[i] = 0; _nodes_constructed[i] = 0; _nodes_transformed[i] = 0; _new_values[i] = 0; }
1269 }
1270 
1271 //----------------------------set_initial_state--------------------------------
1272 // Record info when starting to parse one bytecode
1273 void Parse::BytecodeParseHistogram::set_initial_state( Bytecodes::Code bc ) {
1274   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1275     _initial_bytecode    = bc;
1276     _initial_node_count  = _compiler->unique();
1277     _initial_transforms  = current_count(BPH_transforms);
1278     _initial_values      = current_count(BPH_values);
1279   }
1280 }
1281 
1282 //----------------------------record_change--------------------------------
1283 // Record results of parsing one bytecode
1284 void Parse::BytecodeParseHistogram::record_change() {
1285   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1286     ++_bytecodes_parsed[_initial_bytecode];
1287     _nodes_constructed [_initial_bytecode] += (_compiler->unique() - _initial_node_count);
1288     _nodes_transformed [_initial_bytecode] += (current_count(BPH_transforms) - _initial_transforms);
1289     _new_values        [_initial_bytecode] += (current_count(BPH_values)     - _initial_values);
1290   }
1291 }
1292 
1293 
1294 //----------------------------print--------------------------------------------
1295 void Parse::BytecodeParseHistogram::print(float cutoff) {
1296   ResourceMark rm;
1297   // print profile
1298   int total  = 0;
1299   int i      = 0;
1300   for( i = 0; i < Bytecodes::number_of_codes; ++i ) { total += _bytecodes_parsed[i]; }
1301   int abs_sum = 0;
1302   tty->cr();   //0123456789012345678901234567890123456789012345678901234567890123456789
1303   tty->print_cr("Histogram of %d parsed bytecodes:", total);
1304   if( total == 0 ) { return; }
1305   tty->cr();
1306   tty->print_cr("absolute:  count of compiled bytecodes of this type");
1307   tty->print_cr("relative:  percentage contribution to compiled nodes");
1308   tty->print_cr("nodes   :  Average number of nodes constructed per bytecode");
1309   tty->print_cr("rnodes  :  Significance towards total nodes constructed, (nodes*relative)");
1310   tty->print_cr("transforms: Average amount of tranform progress per bytecode compiled");
1311   tty->print_cr("values  :  Average number of node values improved per bytecode");
1312   tty->print_cr("name    :  Bytecode name");
1313   tty->cr();
1314   tty->print_cr("  absolute  relative   nodes  rnodes  transforms  values   name");
1315   tty->print_cr("----------------------------------------------------------------------");
1316   while (--i > 0) {
1317     int       abs = _bytecodes_parsed[i];
1318     float     rel = abs * 100.0F / total;
1319     float   nodes = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_constructed[i])/_bytecodes_parsed[i];
1320     float  rnodes = _bytecodes_parsed[i] == 0 ? 0 :  rel * nodes;
1321     float  xforms = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_transformed[i])/_bytecodes_parsed[i];
1322     float  values = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _new_values       [i])/_bytecodes_parsed[i];
1323     if (cutoff <= rel) {
1324       tty->print_cr("%10d  %7.2f%%  %6.1f  %6.2f   %6.1f   %6.1f     %s", abs, rel, nodes, rnodes, xforms, values, name_for_bc(i));
1325       abs_sum += abs;
1326     }
1327   }
1328   tty->print_cr("----------------------------------------------------------------------");
1329   float rel_sum = abs_sum * 100.0F / total;
1330   tty->print_cr("%10d  %7.2f%%    (cutoff = %.2f%%)", abs_sum, rel_sum, cutoff);
1331   tty->print_cr("----------------------------------------------------------------------");
1332   tty->cr();
1333 }
1334 #endif
1335 
1336 //----------------------------load_state_from----------------------------------
1337 // Load block/map/sp.  But not do not touch iter/bci.
1338 void Parse::load_state_from(Block* block) {
1339   set_block(block);
1340   // load the block's JVM state:
1341   set_map(block->start_map());
1342   set_sp( block->start_sp());
1343 }
1344 
1345 
1346 //-----------------------------record_state------------------------------------
1347 void Parse::Block::record_state(Parse* p) {
1348   assert(!is_merged(), "can only record state once, on 1st inflow");
1349   assert(start_sp() == p->sp(), "stack pointer must agree with ciTypeFlow");
1350   set_start_map(p->stop());
1351 }
1352 
1353 
1354 //------------------------------do_one_block-----------------------------------
1355 void Parse::do_one_block() {
1356   if (TraceOptoParse) {
1357     Block *b = block();
1358     int ns = b->num_successors();
1359     int nt = b->all_successors();
1360 
1361     tty->print("Parsing block #%d at bci [%d,%d), successors: ",
1362                   block()->rpo(), block()->start(), block()->limit());
1363     for (int i = 0; i < nt; i++) {
1364       tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->rpo());
1365     }
1366     if (b->is_loop_head()) tty->print("  lphd");
1367     tty->print_cr("");
1368   }
1369 
1370   assert(block()->is_merged(), "must be merged before being parsed");
1371   block()->mark_parsed();
1372   ++_blocks_parsed;
1373 
1374   // Set iterator to start of block.
1375   iter().reset_to_bci(block()->start());
1376 
1377   CompileLog* log = C->log();
1378 
1379   // Parse bytecodes
1380   while (!stopped() && !failing()) {
1381     iter().next();
1382 
1383     // Learn the current bci from the iterator:
1384     set_parse_bci(iter().cur_bci());
1385 
1386     if (bci() == block()->limit()) {
1387       // insert a predicate if it falls through to a loop head block
1388       if (should_add_predicate(bci())){
1389         add_predicate();
1390       }
1391       // Do not walk into the next block until directed by do_all_blocks.
1392       merge(bci());
1393       break;
1394     }
1395     assert(bci() < block()->limit(), "bci still in block");
1396 
1397     if (log != NULL) {
1398       // Output an optional context marker, to help place actions
1399       // that occur during parsing of this BC.  If there is no log
1400       // output until the next context string, this context string
1401       // will be silently ignored.
1402       log->context()->reset();
1403       log->context()->print_cr("<bc code='%d' bci='%d'/>", (int)bc(), bci());
1404     }
1405 
1406     if (block()->has_trap_at(bci())) {
1407       // We must respect the flow pass's traps, because it will refuse
1408       // to produce successors for trapping blocks.
1409       int trap_index = block()->flow()->trap_index();
1410       assert(trap_index != 0, "trap index must be valid");
1411       uncommon_trap(trap_index);
1412       break;
1413     }
1414 
1415     NOT_PRODUCT( parse_histogram()->set_initial_state(bc()); );
1416 
1417 #ifdef ASSERT
1418     int pre_bc_sp = sp();
1419     int inputs, depth;
1420     bool have_se = !stopped() && compute_stack_effects(inputs, depth);
1421     assert(!have_se || pre_bc_sp >= inputs, "have enough stack to execute this BC");
1422 #endif //ASSERT
1423 
1424     do_one_bytecode();
1425 
1426     assert(!have_se || stopped() || failing() || (sp() - pre_bc_sp) == depth, "correct depth prediction");
1427 
1428     do_exceptions();
1429 
1430     NOT_PRODUCT( parse_histogram()->record_change(); );
1431 
1432     if (log != NULL)  log->context()->reset();  // done w/ this one
1433 
1434     // Fall into next bytecode.  Each bytecode normally has 1 sequential
1435     // successor which is typically made ready by visiting this bytecode.
1436     // If the successor has several predecessors, then it is a merge
1437     // point, starts a new basic block, and is handled like other basic blocks.
1438   }
1439 }
1440 
1441 
1442 //------------------------------merge------------------------------------------
1443 void Parse::set_parse_bci(int bci) {
1444   set_bci(bci);
1445   Node_Notes* nn = C->default_node_notes();
1446   if (nn == NULL)  return;
1447 
1448   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
1449   if (!DebugInlinedCalls && depth() > 1) {
1450     return;
1451   }
1452 
1453   // Update the JVMS annotation, if present.
1454   JVMState* jvms = nn->jvms();
1455   if (jvms != NULL && jvms->bci() != bci) {
1456     // Update the JVMS.
1457     jvms = jvms->clone_shallow(C);
1458     jvms->set_bci(bci);
1459     nn->set_jvms(jvms);
1460   }
1461 }
1462 
1463 //------------------------------merge------------------------------------------
1464 // Merge the current mapping into the basic block starting at bci
1465 void Parse::merge(int target_bci) {
1466   Block* target = successor_for_bci(target_bci);
1467   if (target == NULL) { handle_missing_successor(target_bci); return; }
1468   assert(!target->is_ready(), "our arrival must be expected");
1469   int pnum = target->next_path_num();
1470   merge_common(target, pnum);
1471 }
1472 
1473 //-------------------------merge_new_path--------------------------------------
1474 // Merge the current mapping into the basic block, using a new path
1475 void Parse::merge_new_path(int target_bci) {
1476   Block* target = successor_for_bci(target_bci);
1477   if (target == NULL) { handle_missing_successor(target_bci); return; }
1478   assert(!target->is_ready(), "new path into frozen graph");
1479   int pnum = target->add_new_path();
1480   merge_common(target, pnum);
1481 }
1482 
1483 //-------------------------merge_exception-------------------------------------
1484 // Merge the current mapping into the basic block starting at bci
1485 // The ex_oop must be pushed on the stack, unlike throw_to_exit.
1486 void Parse::merge_exception(int target_bci) {
1487   assert(sp() == 1, "must have only the throw exception on the stack");
1488   Block* target = successor_for_bci(target_bci);
1489   if (target == NULL) { handle_missing_successor(target_bci); return; }
1490   assert(target->is_handler(), "exceptions are handled by special blocks");
1491   int pnum = target->add_new_path();
1492   merge_common(target, pnum);
1493 }
1494 
1495 //--------------------handle_missing_successor---------------------------------
1496 void Parse::handle_missing_successor(int target_bci) {
1497 #ifndef PRODUCT
1498   Block* b = block();
1499   int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1;
1500   tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci);
1501 #endif
1502   ShouldNotReachHere();
1503 }
1504 
1505 //--------------------------merge_common---------------------------------------
1506 void Parse::merge_common(Parse::Block* target, int pnum) {
1507   if (TraceOptoParse) {
1508     tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start());
1509   }
1510 
1511   // Zap extra stack slots to top
1512   assert(sp() == target->start_sp(), "");
1513   clean_stack(sp());
1514 
1515   if (!target->is_merged()) {   // No prior mapping at this bci
1516     if (TraceOptoParse) { tty->print(" with empty state");  }
1517 
1518     // If this path is dead, do not bother capturing it as a merge.
1519     // It is "as if" we had 1 fewer predecessors from the beginning.
1520     if (stopped()) {
1521       if (TraceOptoParse)  tty->print_cr(", but path is dead and doesn't count");
1522       return;
1523     }
1524 
1525     // Record that a new block has been merged.
1526     ++_blocks_merged;
1527 
1528     // Make a region if we know there are multiple or unpredictable inputs.
1529     // (Also, if this is a plain fall-through, we might see another region,
1530     // which must not be allowed into this block's map.)
1531     if (pnum > PhiNode::Input         // Known multiple inputs.
1532         || target->is_handler()       // These have unpredictable inputs.
1533         || target->is_loop_head()     // Known multiple inputs
1534         || control()->is_Region()) {  // We must hide this guy.
1535       // Add a Region to start the new basic block.  Phis will be added
1536       // later lazily.
1537       int edges = target->pred_count();
1538       if (edges < pnum)  edges = pnum;  // might be a new path!
1539       Node *r = new (C, edges+1) RegionNode(edges+1);
1540       gvn().set_type(r, Type::CONTROL);
1541       record_for_igvn(r);
1542       // zap all inputs to NULL for debugging (done in Node(uint) constructor)
1543       // for (int j = 1; j < edges+1; j++) { r->init_req(j, NULL); }
1544       r->init_req(pnum, control());
1545       set_control(r);
1546     }
1547 
1548     // Convert the existing Parser mapping into a mapping at this bci.
1549     store_state_to(target);
1550     assert(target->is_merged(), "do not come here twice");
1551 
1552   } else {                      // Prior mapping at this bci
1553     if (TraceOptoParse) {  tty->print(" with previous state"); }
1554 
1555     // We must not manufacture more phis if the target is already parsed.
1556     bool nophi = target->is_parsed();
1557 
1558     SafePointNode* newin = map();// Hang on to incoming mapping
1559     Block* save_block = block(); // Hang on to incoming block;
1560     load_state_from(target);    // Get prior mapping
1561 
1562     assert(newin->jvms()->locoff() == jvms()->locoff(), "JVMS layouts agree");
1563     assert(newin->jvms()->stkoff() == jvms()->stkoff(), "JVMS layouts agree");
1564     assert(newin->jvms()->monoff() == jvms()->monoff(), "JVMS layouts agree");
1565     assert(newin->jvms()->endoff() == jvms()->endoff(), "JVMS layouts agree");
1566 
1567     // Iterate over my current mapping and the old mapping.
1568     // Where different, insert Phi functions.
1569     // Use any existing Phi functions.
1570     assert(control()->is_Region(), "must be merging to a region");
1571     RegionNode* r = control()->as_Region();
1572 
1573     // Compute where to merge into
1574     // Merge incoming control path
1575     r->init_req(pnum, newin->control());
1576 
1577     if (pnum == 1) {            // Last merge for this Region?
1578       if (!block()->flow()->is_irreducible_entry()) {
1579         Node* result = _gvn.transform_no_reclaim(r);
1580         if (r != result && TraceOptoParse) {
1581           tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx);
1582         }
1583       }
1584       record_for_igvn(r);
1585     }
1586 
1587     // Update all the non-control inputs to map:
1588     assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms");
1589     bool check_elide_phi = target->is_SEL_backedge(save_block);
1590     for (uint j = 1; j < newin->req(); j++) {
1591       Node* m = map()->in(j);   // Current state of target.
1592       Node* n = newin->in(j);   // Incoming change to target state.
1593       PhiNode* phi;
1594       if (m->is_Phi() && m->as_Phi()->region() == r)
1595         phi = m->as_Phi();
1596       else
1597         phi = NULL;
1598       if (m != n) {             // Different; must merge
1599         switch (j) {
1600         // Frame pointer and Return Address never changes
1601         case TypeFunc::FramePtr:// Drop m, use the original value
1602         case TypeFunc::ReturnAdr:
1603           break;
1604         case TypeFunc::Memory:  // Merge inputs to the MergeMem node
1605           assert(phi == NULL, "the merge contains phis, not vice versa");
1606           merge_memory_edges(n->as_MergeMem(), pnum, nophi);
1607           continue;
1608         default:                // All normal stuff
1609           if (phi == NULL) {
1610             if (!check_elide_phi || !target->can_elide_SEL_phi(j)) {
1611               phi = ensure_phi(j, nophi);
1612             }
1613           }
1614           break;
1615         }
1616       }
1617       // At this point, n might be top if:
1618       //  - there is no phi (because TypeFlow detected a conflict), or
1619       //  - the corresponding control edges is top (a dead incoming path)
1620       // It is a bug if we create a phi which sees a garbage value on a live path.
1621 
1622       if (phi != NULL) {
1623         assert(n != top() || r->in(pnum) == top(), "live value must not be garbage");
1624         assert(phi->region() == r, "");
1625         phi->set_req(pnum, n);  // Then add 'n' to the merge
1626         if (pnum == PhiNode::Input) {
1627           // Last merge for this Phi.
1628           // So far, Phis have had a reasonable type from ciTypeFlow.
1629           // Now _gvn will join that with the meet of current inputs.
1630           // BOTTOM is never permissible here, 'cause pessimistically
1631           // Phis of pointers cannot lose the basic pointer type.
1632           debug_only(const Type* bt1 = phi->bottom_type());
1633           assert(bt1 != Type::BOTTOM, "should not be building conflict phis");
1634           map()->set_req(j, _gvn.transform_no_reclaim(phi));
1635           debug_only(const Type* bt2 = phi->bottom_type());
1636           assert(bt2->higher_equal(bt1), "must be consistent with type-flow");
1637           record_for_igvn(phi);
1638         }
1639       }
1640     } // End of for all values to be merged
1641 
1642     if (pnum == PhiNode::Input &&
1643         !r->in(0)) {         // The occasional useless Region
1644       assert(control() == r, "");
1645       set_control(r->nonnull_req());
1646     }
1647 
1648     // newin has been subsumed into the lazy merge, and is now dead.
1649     set_block(save_block);
1650 
1651     stop();                     // done with this guy, for now
1652   }
1653 
1654   if (TraceOptoParse) {
1655     tty->print_cr(" on path %d", pnum);
1656   }
1657 
1658   // Done with this parser state.
1659   assert(stopped(), "");
1660 }
1661 
1662 
1663 //--------------------------merge_memory_edges---------------------------------
1664 void Parse::merge_memory_edges(MergeMemNode* n, int pnum, bool nophi) {
1665   // (nophi means we must not create phis, because we already parsed here)
1666   assert(n != NULL, "");
1667   // Merge the inputs to the MergeMems
1668   MergeMemNode* m = merged_memory();
1669 
1670   assert(control()->is_Region(), "must be merging to a region");
1671   RegionNode* r = control()->as_Region();
1672 
1673   PhiNode* base = NULL;
1674   MergeMemNode* remerge = NULL;
1675   for (MergeMemStream mms(m, n); mms.next_non_empty2(); ) {
1676     Node *p = mms.force_memory();
1677     Node *q = mms.memory2();
1678     if (mms.is_empty() && nophi) {
1679       // Trouble:  No new splits allowed after a loop body is parsed.
1680       // Instead, wire the new split into a MergeMem on the backedge.
1681       // The optimizer will sort it out, slicing the phi.
1682       if (remerge == NULL) {
1683         assert(base != NULL, "");
1684         assert(base->in(0) != NULL, "should not be xformed away");
1685         remerge = MergeMemNode::make(C, base->in(pnum));
1686         gvn().set_type(remerge, Type::MEMORY);
1687         base->set_req(pnum, remerge);
1688       }
1689       remerge->set_memory_at(mms.alias_idx(), q);
1690       continue;
1691     }
1692     assert(!q->is_MergeMem(), "");
1693     PhiNode* phi;
1694     if (p != q) {
1695       phi = ensure_memory_phi(mms.alias_idx(), nophi);
1696     } else {
1697       if (p->is_Phi() && p->as_Phi()->region() == r)
1698         phi = p->as_Phi();
1699       else
1700         phi = NULL;
1701     }
1702     // Insert q into local phi
1703     if (phi != NULL) {
1704       assert(phi->region() == r, "");
1705       p = phi;
1706       phi->set_req(pnum, q);
1707       if (mms.at_base_memory()) {
1708         base = phi;  // delay transforming it
1709       } else if (pnum == 1) {
1710         record_for_igvn(phi);
1711         p = _gvn.transform_no_reclaim(phi);
1712       }
1713       mms.set_memory(p);// store back through the iterator
1714     }
1715   }
1716   // Transform base last, in case we must fiddle with remerging.
1717   if (base != NULL && pnum == 1) {
1718     record_for_igvn(base);
1719     m->set_base_memory( _gvn.transform_no_reclaim(base) );
1720   }
1721 }
1722 
1723 
1724 //------------------------ensure_phis_everywhere-------------------------------
1725 void Parse::ensure_phis_everywhere() {
1726   ensure_phi(TypeFunc::I_O);
1727 
1728   // Ensure a phi on all currently known memories.
1729   for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
1730     ensure_memory_phi(mms.alias_idx());
1731     debug_only(mms.set_memory());  // keep the iterator happy
1732   }
1733 
1734   // Note:  This is our only chance to create phis for memory slices.
1735   // If we miss a slice that crops up later, it will have to be
1736   // merged into the base-memory phi that we are building here.
1737   // Later, the optimizer will comb out the knot, and build separate
1738   // phi-loops for each memory slice that matters.
1739 
1740   // Monitors must nest nicely and not get confused amongst themselves.
1741   // Phi-ify everything up to the monitors, though.
1742   uint monoff = map()->jvms()->monoff();
1743   uint nof_monitors = map()->jvms()->nof_monitors();
1744 
1745   assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms");
1746   bool check_elide_phi = block()->is_SEL_head();
1747   for (uint i = TypeFunc::Parms; i < monoff; i++) {
1748     if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) {
1749       ensure_phi(i);
1750     }
1751   }
1752 
1753   // Even monitors need Phis, though they are well-structured.
1754   // This is true for OSR methods, and also for the rare cases where
1755   // a monitor object is the subject of a replace_in_map operation.
1756   // See bugs 4426707 and 5043395.
1757   for (uint m = 0; m < nof_monitors; m++) {
1758     ensure_phi(map()->jvms()->monitor_obj_offset(m));
1759   }
1760 }
1761 
1762 
1763 //-----------------------------add_new_path------------------------------------
1764 // Add a previously unaccounted predecessor to this block.
1765 int Parse::Block::add_new_path() {
1766   // If there is no map, return the lowest unused path number.
1767   if (!is_merged())  return pred_count()+1;  // there will be a map shortly
1768 
1769   SafePointNode* map = start_map();
1770   if (!map->control()->is_Region())
1771     return pred_count()+1;  // there may be a region some day
1772   RegionNode* r = map->control()->as_Region();
1773 
1774   // Add new path to the region.
1775   uint pnum = r->req();
1776   r->add_req(NULL);
1777 
1778   for (uint i = 1; i < map->req(); i++) {
1779     Node* n = map->in(i);
1780     if (i == TypeFunc::Memory) {
1781       // Ensure a phi on all currently known memories.
1782       for (MergeMemStream mms(n->as_MergeMem()); mms.next_non_empty(); ) {
1783         Node* phi = mms.memory();
1784         if (phi->is_Phi() && phi->as_Phi()->region() == r) {
1785           assert(phi->req() == pnum, "must be same size as region");
1786           phi->add_req(NULL);
1787         }
1788       }
1789     } else {
1790       if (n->is_Phi() && n->as_Phi()->region() == r) {
1791         assert(n->req() == pnum, "must be same size as region");
1792         n->add_req(NULL);
1793       }
1794     }
1795   }
1796 
1797   return pnum;
1798 }
1799 
1800 //------------------------------ensure_phi-------------------------------------
1801 // Turn the idx'th entry of the current map into a Phi
1802 PhiNode *Parse::ensure_phi(int idx, bool nocreate) {
1803   SafePointNode* map = this->map();
1804   Node* region = map->control();
1805   assert(region->is_Region(), "");
1806 
1807   Node* o = map->in(idx);
1808   assert(o != NULL, "");
1809 
1810   if (o == top())  return NULL; // TOP always merges into TOP
1811 
1812   if (o->is_Phi() && o->as_Phi()->region() == region) {
1813     return o->as_Phi();
1814   }
1815 
1816   // Now use a Phi here for merging
1817   assert(!nocreate, "Cannot build a phi for a block already parsed.");
1818   const JVMState* jvms = map->jvms();
1819   const Type* t;
1820   if (jvms->is_loc(idx)) {
1821     t = block()->local_type_at(idx - jvms->locoff());
1822   } else if (jvms->is_stk(idx)) {
1823     t = block()->stack_type_at(idx - jvms->stkoff());
1824   } else if (jvms->is_mon(idx)) {
1825     assert(!jvms->is_monitor_box(idx), "no phis for boxes");
1826     t = TypeInstPtr::BOTTOM; // this is sufficient for a lock object
1827   } else if ((uint)idx < TypeFunc::Parms) {
1828     t = o->bottom_type();  // Type::RETURN_ADDRESS or such-like.
1829   } else {
1830     assert(false, "no type information for this phi");
1831   }
1832 
1833   // If the type falls to bottom, then this must be a local that
1834   // is mixing ints and oops or some such.  Forcing it to top
1835   // makes it go dead.
1836   if (t == Type::BOTTOM) {
1837     map->set_req(idx, top());
1838     return NULL;
1839   }
1840 
1841   // Do not create phis for top either.
1842   // A top on a non-null control flow must be an unused even after the.phi.
1843   if (t == Type::TOP || t == Type::HALF) {
1844     map->set_req(idx, top());
1845     return NULL;
1846   }
1847 
1848   PhiNode* phi = PhiNode::make(region, o, t);
1849   gvn().set_type(phi, t);
1850   if (C->do_escape_analysis()) record_for_igvn(phi);
1851   map->set_req(idx, phi);
1852   return phi;
1853 }
1854 
1855 //--------------------------ensure_memory_phi----------------------------------
1856 // Turn the idx'th slice of the current memory into a Phi
1857 PhiNode *Parse::ensure_memory_phi(int idx, bool nocreate) {
1858   MergeMemNode* mem = merged_memory();
1859   Node* region = control();
1860   assert(region->is_Region(), "");
1861 
1862   Node *o = (idx == Compile::AliasIdxBot)? mem->base_memory(): mem->memory_at(idx);
1863   assert(o != NULL && o != top(), "");
1864 
1865   PhiNode* phi;
1866   if (o->is_Phi() && o->as_Phi()->region() == region) {
1867     phi = o->as_Phi();
1868     if (phi == mem->base_memory() && idx >= Compile::AliasIdxRaw) {
1869       // clone the shared base memory phi to make a new memory split
1870       assert(!nocreate, "Cannot build a phi for a block already parsed.");
1871       const Type* t = phi->bottom_type();
1872       const TypePtr* adr_type = C->get_adr_type(idx);
1873       phi = phi->slice_memory(adr_type);
1874       gvn().set_type(phi, t);
1875     }
1876     return phi;
1877   }
1878 
1879   // Now use a Phi here for merging
1880   assert(!nocreate, "Cannot build a phi for a block already parsed.");
1881   const Type* t = o->bottom_type();
1882   const TypePtr* adr_type = C->get_adr_type(idx);
1883   phi = PhiNode::make(region, o, t, adr_type);
1884   gvn().set_type(phi, t);
1885   if (idx == Compile::AliasIdxBot)
1886     mem->set_base_memory(phi);
1887   else
1888     mem->set_memory_at(idx, phi);
1889   return phi;
1890 }
1891 
1892 //------------------------------call_register_finalizer-----------------------
1893 // Check the klass of the receiver and call register_finalizer if the
1894 // class need finalization.
1895 void Parse::call_register_finalizer() {
1896   Node* receiver = local(0);
1897   assert(receiver != NULL && receiver->bottom_type()->isa_instptr() != NULL,
1898          "must have non-null instance type");
1899 
1900   const TypeInstPtr *tinst = receiver->bottom_type()->isa_instptr();
1901   if (tinst != NULL && tinst->klass()->is_loaded() && !tinst->klass_is_exact()) {
1902     // The type isn't known exactly so see if CHA tells us anything.
1903     ciInstanceKlass* ik = tinst->klass()->as_instance_klass();
1904     if (!Dependencies::has_finalizable_subclass(ik)) {
1905       // No finalizable subclasses so skip the dynamic check.
1906       C->dependencies()->assert_has_no_finalizable_subclasses(ik);
1907       return;
1908     }
1909   }
1910 
1911   // Insert a dynamic test for whether the instance needs
1912   // finalization.  In general this will fold up since the concrete
1913   // class is often visible so the access flags are constant.
1914   Node* klass_addr = basic_plus_adr( receiver, receiver, oopDesc::klass_offset_in_bytes() );
1915   Node* klass = _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), klass_addr, TypeInstPtr::KLASS) );
1916 
1917   Node* access_flags_addr = basic_plus_adr(klass, klass, Klass::access_flags_offset_in_bytes() + sizeof(oopDesc));
1918   Node* access_flags = make_load(NULL, access_flags_addr, TypeInt::INT, T_INT);
1919 
1920   Node* mask  = _gvn.transform(new (C, 3) AndINode(access_flags, intcon(JVM_ACC_HAS_FINALIZER)));
1921   Node* check = _gvn.transform(new (C, 3) CmpINode(mask, intcon(0)));
1922   Node* test  = _gvn.transform(new (C, 2) BoolNode(check, BoolTest::ne));
1923 
1924   IfNode* iff = create_and_map_if(control(), test, PROB_MAX, COUNT_UNKNOWN);
1925 
1926   RegionNode* result_rgn = new (C, 3) RegionNode(3);
1927   record_for_igvn(result_rgn);
1928 
1929   Node *skip_register = _gvn.transform(new (C, 1) IfFalseNode(iff));
1930   result_rgn->init_req(1, skip_register);
1931 
1932   Node *needs_register = _gvn.transform(new (C, 1) IfTrueNode(iff));
1933   set_control(needs_register);
1934   if (stopped()) {
1935     // There is no slow path.
1936     result_rgn->init_req(2, top());
1937   } else {
1938     Node *call = make_runtime_call(RC_NO_LEAF,
1939                                    OptoRuntime::register_finalizer_Type(),
1940                                    OptoRuntime::register_finalizer_Java(),
1941                                    NULL, TypePtr::BOTTOM,
1942                                    receiver);
1943     make_slow_call_ex(call, env()->Throwable_klass(), true);
1944 
1945     Node* fast_io  = call->in(TypeFunc::I_O);
1946     Node* fast_mem = call->in(TypeFunc::Memory);
1947     // These two phis are pre-filled with copies of of the fast IO and Memory
1948     Node* io_phi   = PhiNode::make(result_rgn, fast_io,  Type::ABIO);
1949     Node* mem_phi  = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);
1950 
1951     result_rgn->init_req(2, control());
1952     io_phi    ->init_req(2, i_o());
1953     mem_phi   ->init_req(2, reset_memory());
1954 
1955     set_all_memory( _gvn.transform(mem_phi) );
1956     set_i_o(        _gvn.transform(io_phi) );
1957   }
1958 
1959   set_control( _gvn.transform(result_rgn) );
1960 }
1961 
1962 //------------------------------return_current---------------------------------
1963 // Append current _map to _exit_return
1964 void Parse::return_current(Node* value) {
1965   if (RegisterFinalizersAtInit &&
1966       method()->intrinsic_id() == vmIntrinsics::_Object_init) {
1967     call_register_finalizer();
1968   }
1969 
1970   // Do not set_parse_bci, so that return goo is credited to the return insn.
1971   set_bci(InvocationEntryBci);
1972   if (method()->is_synchronized() && GenerateSynchronizationCode) {
1973     shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
1974   }
1975   if (C->env()->dtrace_method_probes()) {
1976     make_dtrace_method_exit(method());
1977   }
1978   SafePointNode* exit_return = _exits.map();
1979   exit_return->in( TypeFunc::Control  )->add_req( control() );
1980   exit_return->in( TypeFunc::I_O      )->add_req( i_o    () );
1981   Node *mem = exit_return->in( TypeFunc::Memory   );
1982   for (MergeMemStream mms(mem->as_MergeMem(), merged_memory()); mms.next_non_empty2(); ) {
1983     if (mms.is_empty()) {
1984       // get a copy of the base memory, and patch just this one input
1985       const TypePtr* adr_type = mms.adr_type(C);
1986       Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
1987       assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
1988       gvn().set_type_bottom(phi);
1989       phi->del_req(phi->req()-1);  // prepare to re-patch
1990       mms.set_memory(phi);
1991     }
1992     mms.memory()->add_req(mms.memory2());
1993   }
1994 
1995   // frame pointer is always same, already captured
1996   if (value != NULL) {
1997     // If returning oops to an interface-return, there is a silent free
1998     // cast from oop to interface allowed by the Verifier.  Make it explicit
1999     // here.
2000     Node* phi = _exits.argument(0);
2001     const TypeInstPtr *tr = phi->bottom_type()->isa_instptr();
2002     if( tr && tr->klass()->is_loaded() &&
2003         tr->klass()->is_interface() ) {
2004       const TypeInstPtr *tp = value->bottom_type()->isa_instptr();
2005       if (tp && tp->klass()->is_loaded() &&
2006           !tp->klass()->is_interface()) {
2007         // sharpen the type eagerly; this eases certain assert checking
2008         if (tp->higher_equal(TypeInstPtr::NOTNULL))
2009           tr = tr->join(TypeInstPtr::NOTNULL)->is_instptr();
2010         value = _gvn.transform(new (C, 2) CheckCastPPNode(0,value,tr));
2011       }
2012     }
2013     phi->add_req(value);
2014   }
2015 
2016   stop_and_kill_map();          // This CFG path dies here
2017 }
2018 
2019 
2020 //------------------------------add_safepoint----------------------------------
2021 void Parse::add_safepoint() {
2022   // See if we can avoid this safepoint.  No need for a SafePoint immediately
2023   // after a Call (except Leaf Call) or another SafePoint.
2024   Node *proj = control();
2025   bool add_poll_param = SafePointNode::needs_polling_address_input();
2026   uint parms = add_poll_param ? TypeFunc::Parms+1 : TypeFunc::Parms;
2027   if( proj->is_Proj() ) {
2028     Node *n0 = proj->in(0);
2029     if( n0->is_Catch() ) {
2030       n0 = n0->in(0)->in(0);
2031       assert( n0->is_Call(), "expect a call here" );
2032     }
2033     if( n0->is_Call() ) {
2034       if( n0->as_Call()->guaranteed_safepoint() )
2035         return;
2036     } else if( n0->is_SafePoint() && n0->req() >= parms ) {
2037       return;
2038     }
2039   }
2040 
2041   // Clear out dead values from the debug info.
2042   kill_dead_locals();
2043 
2044   // Clone the JVM State
2045   SafePointNode *sfpnt = new (C, parms) SafePointNode(parms, NULL);
2046 
2047   // Capture memory state BEFORE a SafePoint.  Since we can block at a
2048   // SafePoint we need our GC state to be safe; i.e. we need all our current
2049   // write barriers (card marks) to not float down after the SafePoint so we
2050   // must read raw memory.  Likewise we need all oop stores to match the card
2051   // marks.  If deopt can happen, we need ALL stores (we need the correct JVM
2052   // state on a deopt).
2053 
2054   // We do not need to WRITE the memory state after a SafePoint.  The control
2055   // edge will keep card-marks and oop-stores from floating up from below a
2056   // SafePoint and our true dependency added here will keep them from floating
2057   // down below a SafePoint.
2058 
2059   // Clone the current memory state
2060   Node* mem = MergeMemNode::make(C, map()->memory());
2061 
2062   mem = _gvn.transform(mem);
2063 
2064   // Pass control through the safepoint
2065   sfpnt->init_req(TypeFunc::Control  , control());
2066   // Fix edges normally used by a call
2067   sfpnt->init_req(TypeFunc::I_O      , top() );
2068   sfpnt->init_req(TypeFunc::Memory   , mem   );
2069   sfpnt->init_req(TypeFunc::ReturnAdr, top() );
2070   sfpnt->init_req(TypeFunc::FramePtr , top() );
2071 
2072   // Create a node for the polling address
2073   if( add_poll_param ) {
2074     Node *polladr = ConPNode::make(C, (address)os::get_polling_page());
2075     sfpnt->init_req(TypeFunc::Parms+0, _gvn.transform(polladr));
2076   }
2077 
2078   // Fix up the JVM State edges
2079   add_safepoint_edges(sfpnt);
2080   Node *transformed_sfpnt = _gvn.transform(sfpnt);
2081   set_control(transformed_sfpnt);
2082 
2083   // Provide an edge from root to safepoint.  This makes the safepoint
2084   // appear useful until the parse has completed.
2085   if( OptoRemoveUseless && transformed_sfpnt->is_SafePoint() ) {
2086     assert(C->root() != NULL, "Expect parse is still valid");
2087     C->root()->add_prec(transformed_sfpnt);
2088   }
2089 }
2090 
2091 //------------------------------should_add_predicate--------------------------
2092 bool Parse::should_add_predicate(int target_bci) {
2093   if (!UseLoopPredicate) return false;
2094   Block* target = successor_for_bci(target_bci);
2095   if (target != NULL          &&
2096       target->is_loop_head()  &&
2097       block()->rpo() < target->rpo()) {
2098     return true;
2099   }
2100   return false;
2101 }
2102 
2103 //------------------------------add_predicate---------------------------------
2104 void Parse::add_predicate() {
2105   assert(UseLoopPredicate,"use only for loop predicate");
2106   Node *cont    = _gvn.intcon(1);
2107   Node* opq     = _gvn.transform(new (C, 2) Opaque1Node(C, cont));
2108   Node *bol     = _gvn.transform(new (C, 2) Conv2BNode(opq));
2109   IfNode* iff   = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
2110   Node* iffalse = _gvn.transform(new (C, 1) IfFalseNode(iff));
2111   C->add_predicate_opaq(opq);
2112   {
2113     PreserveJVMState pjvms(this);
2114     set_control(iffalse);
2115     uncommon_trap(Deoptimization::Reason_predicate,
2116                   Deoptimization::Action_maybe_recompile);
2117   }
2118   Node* iftrue = _gvn.transform(new (C, 1) IfTrueNode(iff));
2119   set_control(iftrue);
2120 }
2121 
2122 #ifndef PRODUCT
2123 //------------------------show_parse_info--------------------------------------
2124 void Parse::show_parse_info() {
2125   InlineTree* ilt = NULL;
2126   if (C->ilt() != NULL) {
2127     JVMState* caller_jvms = is_osr_parse() ? caller()->caller() : caller();
2128     ilt = InlineTree::find_subtree_from_root(C->ilt(), caller_jvms, method());
2129   }
2130   if (PrintCompilation && Verbose) {
2131     if (depth() == 1) {
2132       if( ilt->count_inlines() ) {
2133         tty->print("    __inlined %d (%d bytes)", ilt->count_inlines(),
2134                      ilt->count_inline_bcs());
2135         tty->cr();
2136       }
2137     } else {
2138       if (method()->is_synchronized())         tty->print("s");
2139       if (method()->has_exception_handlers())  tty->print("!");
2140       // Check this is not the final compiled version
2141       if (C->trap_can_recompile()) {
2142         tty->print("-");
2143       } else {
2144         tty->print(" ");
2145       }
2146       method()->print_short_name();
2147       if (is_osr_parse()) {
2148         tty->print(" @ %d", osr_bci());
2149       }
2150       tty->print(" (%d bytes)",method()->code_size());
2151       if (ilt->count_inlines()) {
2152         tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2153                    ilt->count_inline_bcs());
2154       }
2155       tty->cr();
2156     }
2157   }
2158   if (PrintOpto && (depth() == 1 || PrintOptoInlining)) {
2159     // Print that we succeeded; suppress this message on the first osr parse.
2160 
2161     if (method()->is_synchronized())         tty->print("s");
2162     if (method()->has_exception_handlers())  tty->print("!");
2163     // Check this is not the final compiled version
2164     if (C->trap_can_recompile() && depth() == 1) {
2165       tty->print("-");
2166     } else {
2167       tty->print(" ");
2168     }
2169     if( depth() != 1 ) { tty->print("   "); }  // missing compile count
2170     for (int i = 1; i < depth(); ++i) { tty->print("  "); }
2171     method()->print_short_name();
2172     if (is_osr_parse()) {
2173       tty->print(" @ %d", osr_bci());
2174     }
2175     if (ilt->caller_bci() != -1) {
2176       tty->print(" @ %d", ilt->caller_bci());
2177     }
2178     tty->print(" (%d bytes)",method()->code_size());
2179     if (ilt->count_inlines()) {
2180       tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2181                  ilt->count_inline_bcs());
2182     }
2183     tty->cr();
2184   }
2185 }
2186 
2187 
2188 //------------------------------dump-------------------------------------------
2189 // Dump information associated with the bytecodes of current _method
2190 void Parse::dump() {
2191   if( method() != NULL ) {
2192     // Iterate over bytecodes
2193     ciBytecodeStream iter(method());
2194     for( Bytecodes::Code bc = iter.next(); bc != ciBytecodeStream::EOBC() ; bc = iter.next() ) {
2195       dump_bci( iter.cur_bci() );
2196       tty->cr();
2197     }
2198   }
2199 }
2200 
2201 // Dump information associated with a byte code index, 'bci'
2202 void Parse::dump_bci(int bci) {
2203   // Output info on merge-points, cloning, and within _jsr..._ret
2204   // NYI
2205   tty->print(" bci:%d", bci);
2206 }
2207 
2208 #endif