1 /*
   2  * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "compiler/compileLog.hpp"
  26 #include "interpreter/linkResolver.hpp"
  27 #include "memory/resourceArea.hpp"
  28 #include "oops/method.hpp"
  29 #include "opto/addnode.hpp"
  30 #include "opto/c2compiler.hpp"
  31 #include "opto/castnode.hpp"
  32 #include "opto/convertnode.hpp"
  33 #include "opto/idealGraphPrinter.hpp"
  34 #include "opto/inlinetypenode.hpp"
  35 #include "opto/locknode.hpp"
  36 #include "opto/memnode.hpp"
  37 #include "opto/opaquenode.hpp"
  38 #include "opto/parse.hpp"
  39 #include "opto/rootnode.hpp"
  40 #include "opto/runtime.hpp"
  41 #include "opto/type.hpp"
  42 #include "runtime/arguments.hpp"
  43 #include "runtime/handles.inline.hpp"
  44 #include "runtime/safepointMechanism.hpp"
  45 #include "runtime/sharedRuntime.hpp"
  46 #include "utilities/bitMap.inline.hpp"
  47 #include "utilities/copy.hpp"
  48 
  49 // Static array so we can figure out which bytecodes stop us from compiling
  50 // the most. Some of the non-static variables are needed in bytecodeInfo.cpp
  51 // and eventually should be encapsulated in a proper class (gri 8/18/98).
  52 
  53 #ifndef PRODUCT
  54 uint nodes_created             = 0;
  55 uint methods_parsed            = 0;
  56 uint methods_seen              = 0;
  57 uint blocks_parsed             = 0;
  58 uint blocks_seen               = 0;
  59 
  60 uint explicit_null_checks_inserted = 0;
  61 uint explicit_null_checks_elided   = 0;
  62 uint all_null_checks_found         = 0;
  63 uint implicit_null_checks          = 0;
  64 
  65 bool Parse::BytecodeParseHistogram::_initialized = false;
  66 uint Parse::BytecodeParseHistogram::_bytecodes_parsed [Bytecodes::number_of_codes];
  67 uint Parse::BytecodeParseHistogram::_nodes_constructed[Bytecodes::number_of_codes];
  68 uint Parse::BytecodeParseHistogram::_nodes_transformed[Bytecodes::number_of_codes];
  69 uint Parse::BytecodeParseHistogram::_new_values       [Bytecodes::number_of_codes];
  70 
  71 //------------------------------print_statistics-------------------------------
  72 void Parse::print_statistics() {
  73   tty->print_cr("--- Compiler Statistics ---");
  74   tty->print("Methods seen: %u  Methods parsed: %u", methods_seen, methods_parsed);
  75   tty->print("  Nodes created: %u", nodes_created);
  76   tty->cr();
  77   if (methods_seen != methods_parsed) {
  78     tty->print_cr("Reasons for parse failures (NOT cumulative):");
  79   }
  80   tty->print_cr("Blocks parsed: %u  Blocks seen: %u", blocks_parsed, blocks_seen);
  81 
  82   if (explicit_null_checks_inserted) {
  83     tty->print_cr("%u original null checks - %u elided (%2u%%); optimizer leaves %u,",
  84                   explicit_null_checks_inserted, explicit_null_checks_elided,
  85                   (100*explicit_null_checks_elided)/explicit_null_checks_inserted,
  86                   all_null_checks_found);
  87   }
  88   if (all_null_checks_found) {
  89     tty->print_cr("%u made implicit (%2u%%)", implicit_null_checks,
  90                   (100*implicit_null_checks)/all_null_checks_found);
  91   }
  92   if (SharedRuntime::_implicit_null_throws) {
  93     tty->print_cr("%u implicit null exceptions at runtime",
  94                   SharedRuntime::_implicit_null_throws);
  95   }
  96 
  97   if (PrintParseStatistics && BytecodeParseHistogram::initialized()) {
  98     BytecodeParseHistogram::print();
  99   }
 100 }
 101 #endif
 102 
 103 //------------------------------ON STACK REPLACEMENT---------------------------
 104 
 105 // Construct a node which can be used to get incoming state for
 106 // on stack replacement.
 107 Node* Parse::fetch_interpreter_state(int index,
 108                                      const Type* type,
 109                                      Node* local_addrs,
 110                                      Node* local_addrs_base) {
 111   BasicType bt = type->basic_type();
 112   if (type == TypePtr::NULL_PTR) {
 113     // Ptr types are mixed together with T_ADDRESS but nullptr is
 114     // really for T_OBJECT types so correct it.
 115     bt = T_OBJECT;
 116   }
 117   Node *mem = memory(Compile::AliasIdxRaw);
 118   Node *adr = basic_plus_adr( local_addrs_base, local_addrs, -index*wordSize );
 119   Node *ctl = control();
 120 
 121   // Very similar to LoadNode::make, except we handle un-aligned longs and
 122   // doubles on Sparc.  Intel can handle them just fine directly.
 123   Node *l = nullptr;
 124   switch (bt) {                // Signature is flattened
 125   case T_INT:     l = new LoadINode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInt::INT,        MemNode::unordered); break;
 126   case T_FLOAT:   l = new LoadFNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::FLOAT,         MemNode::unordered); break;
 127   case T_ADDRESS: l = new LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,  MemNode::unordered); break;
 128   case T_OBJECT:  l = new LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInstPtr::BOTTOM, MemNode::unordered); break;
 129   case T_LONG:
 130   case T_DOUBLE: {
 131     // Since arguments are in reverse order, the argument address 'adr'
 132     // refers to the back half of the long/double.  Recompute adr.
 133     adr = basic_plus_adr(local_addrs_base, local_addrs, -(index+1)*wordSize);
 134     if (Matcher::misaligned_doubles_ok) {
 135       l = (bt == T_DOUBLE)
 136         ? (Node*)new LoadDNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::DOUBLE, MemNode::unordered)
 137         : (Node*)new LoadLNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeLong::LONG, MemNode::unordered);
 138     } else {
 139       l = (bt == T_DOUBLE)
 140         ? (Node*)new LoadD_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered)
 141         : (Node*)new LoadL_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered);
 142     }
 143     break;
 144   }
 145   default: ShouldNotReachHere();
 146   }
 147   return _gvn.transform(l);
 148 }
 149 
 150 // Helper routine to prevent the interpreter from handing
 151 // unexpected typestate to an OSR method.
 152 // The Node l is a value newly dug out of the interpreter frame.
 153 // The type is the type predicted by ciTypeFlow.  Note that it is
 154 // not a general type, but can only come from Type::get_typeflow_type.
 155 // The safepoint is a map which will feed an uncommon trap.
 156 Node* Parse::check_interpreter_type(Node* l, const Type* type, const TypeKlassPtr* klass_type,
 157                                     SafePointNode* &bad_type_exit, bool is_early_larval) {
 158   const TypeOopPtr* tp = type->isa_oopptr();
 159 
 160   // TypeFlow may assert null-ness if a type appears unloaded.
 161   if (type == TypePtr::NULL_PTR ||
 162       (tp != nullptr && !tp->is_loaded())) {
 163     // Value must be null, not a real oop.
 164     Node* chk = _gvn.transform( new CmpPNode(l, null()) );
 165     Node* tst = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
 166     IfNode* iff = create_and_map_if(control(), tst, PROB_MAX, COUNT_UNKNOWN);
 167     set_control(_gvn.transform( new IfTrueNode(iff) ));
 168     Node* bad_type = _gvn.transform( new IfFalseNode(iff) );
 169     bad_type_exit->control()->add_req(bad_type);
 170     l = null();
 171   }
 172 
 173   // Typeflow can also cut off paths from the CFG, based on
 174   // types which appear unloaded, or call sites which appear unlinked.
 175   // When paths are cut off, values at later merge points can rise
 176   // toward more specific classes.  Make sure these specific classes
 177   // are still in effect.
 178   if (tp != nullptr && !tp->is_same_java_type_as(TypeInstPtr::BOTTOM)) {
 179     // TypeFlow asserted a specific object type.  Value must have that type.
 180     Node* bad_type_ctrl = nullptr;
 181     if (tp->is_inlinetypeptr() && !tp->maybe_null()) {
 182       // Check inline types for null here to prevent checkcast from adding an
 183       // exception state before the bytecode entry (use 'bad_type_ctrl' instead).
 184       l = null_check_oop(l, &bad_type_ctrl);
 185       bad_type_exit->control()->add_req(bad_type_ctrl);
 186     }
 187 
 188     l = gen_checkcast(l, makecon(klass_type), &bad_type_ctrl, false, is_early_larval);
 189     bad_type_exit->control()->add_req(bad_type_ctrl);
 190   }
 191 
 192   assert(_gvn.type(l)->higher_equal(type), "must constrain OSR typestate");
 193   return l;
 194 }
 195 
 196 // Helper routine which sets up elements of the initial parser map when
 197 // performing a parse for on stack replacement.  Add values into map.
 198 // The only parameter contains the address of a interpreter arguments.
 199 void Parse::load_interpreter_state(Node* osr_buf) {
 200   int index;
 201   int max_locals = jvms()->loc_size();
 202   int max_stack  = jvms()->stk_size();
 203 
 204   // Mismatch between method and jvms can occur since map briefly held
 205   // an OSR entry state (which takes up one RawPtr word).
 206   assert(max_locals == method()->max_locals(), "sanity");
 207   assert(max_stack  >= method()->max_stack(),  "sanity");
 208   assert((int)jvms()->endoff() == TypeFunc::Parms + max_locals + max_stack, "sanity");
 209   assert((int)jvms()->endoff() == (int)map()->req(), "sanity");
 210 
 211   // Find the start block.
 212   Block* osr_block = start_block();
 213   assert(osr_block->start() == osr_bci(), "sanity");
 214 
 215   // Set initial BCI.
 216   set_parse_bci(osr_block->start());
 217 
 218   // Set initial stack depth.
 219   set_sp(osr_block->start_sp());
 220 
 221   // Check bailouts.  We currently do not perform on stack replacement
 222   // of loops in catch blocks or loops which branch with a non-empty stack.
 223   if (sp() != 0) {
 224     C->record_method_not_compilable("OSR starts with non-empty stack");
 225     return;
 226   }
 227   // Do not OSR inside finally clauses:
 228   if (osr_block->has_trap_at(osr_block->start())) {
 229     assert(false, "OSR starts with an immediate trap");
 230     C->record_method_not_compilable("OSR starts with an immediate trap");
 231     return;
 232   }
 233 
 234   // Commute monitors from interpreter frame to compiler frame.
 235   assert(jvms()->monitor_depth() == 0, "should be no active locks at beginning of osr");
 236   int mcnt = osr_block->flow()->monitor_count();
 237   Node *monitors_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals+mcnt*2-1)*wordSize);
 238   for (index = 0; index < mcnt; index++) {
 239     // Make a BoxLockNode for the monitor.
 240     BoxLockNode* osr_box = new BoxLockNode(next_monitor());
 241     // Check for bailout after new BoxLockNode
 242     if (failing()) { return; }
 243 
 244     // This OSR locking region is unbalanced because it does not have Lock node:
 245     // locking was done in Interpreter.
 246     // This is similar to Coarsened case when Lock node is eliminated
 247     // and as result the region is marked as Unbalanced.
 248 
 249     // Emulate Coarsened state transition from Regular to Unbalanced.
 250     osr_box->set_coarsened();
 251     osr_box->set_unbalanced();
 252 
 253     Node* box = _gvn.transform(osr_box);
 254 
 255     // Displaced headers and locked objects are interleaved in the
 256     // temp OSR buffer.  We only copy the locked objects out here.
 257     // Fetch the locked object from the OSR temp buffer and copy to our fastlock node.
 258     Node* lock_object = fetch_interpreter_state(index*2, Type::get_const_basic_type(T_OBJECT), monitors_addr, osr_buf);
 259     // Try and copy the displaced header to the BoxNode
 260     Node* displaced_hdr = fetch_interpreter_state((index*2) + 1, Type::get_const_basic_type(T_ADDRESS), monitors_addr, osr_buf);
 261 
 262     store_to_memory(control(), box, displaced_hdr, T_ADDRESS, MemNode::unordered);
 263 
 264     // Build a bogus FastLockNode (no code will be generated) and push the
 265     // monitor into our debug info.
 266     const FastLockNode *flock = _gvn.transform(new FastLockNode( nullptr, lock_object, box ))->as_FastLock();
 267     map()->push_monitor(flock);
 268 
 269     // If the lock is our method synchronization lock, tuck it away in
 270     // _sync_lock for return and rethrow exit paths.
 271     if (index == 0 && method()->is_synchronized()) {
 272       _synch_lock = flock;
 273     }
 274   }
 275 
 276   // Use the raw liveness computation to make sure that unexpected
 277   // values don't propagate into the OSR frame.
 278   MethodLivenessResult live_locals = method()->liveness_at_bci(osr_bci());
 279   if (!live_locals.is_valid()) {
 280     // Degenerate or breakpointed method.
 281     assert(false, "OSR in empty or breakpointed method");
 282     C->record_method_not_compilable("OSR in empty or breakpointed method");
 283     return;
 284   }
 285 
 286   // Extract the needed locals from the interpreter frame.
 287   Node *locals_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals-1)*wordSize);
 288 
 289   // find all the locals that the interpreter thinks contain live oops
 290   const ResourceBitMap live_oops = method()->live_local_oops_at_bci(osr_bci());
 291   for (index = 0; index < max_locals; index++) {
 292 
 293     if (!live_locals.at(index)) {
 294       continue;
 295     }
 296 
 297     const Type *type = osr_block->local_type_at(index);
 298 
 299     if (type->isa_oopptr() != nullptr) {
 300 
 301       // 6403625: Verify that the interpreter oopMap thinks that the oop is live
 302       // else we might load a stale oop if the MethodLiveness disagrees with the
 303       // result of the interpreter. If the interpreter says it is dead we agree
 304       // by making the value go to top.
 305       //
 306 
 307       if (!live_oops.at(index)) {
 308         if (C->log() != nullptr) {
 309           C->log()->elem("OSR_mismatch local_index='%d'",index);
 310         }
 311         set_local(index, null());
 312         // and ignore it for the loads
 313         continue;
 314       }
 315     }
 316 
 317     // Filter out TOP, HALF, and BOTTOM.  (Cf. ensure_phi.)
 318     if (type == Type::TOP || type == Type::HALF) {
 319       continue;
 320     }
 321     // If the type falls to bottom, then this must be a local that
 322     // is mixing ints and oops or some such.  Forcing it to top
 323     // makes it go dead.
 324     if (type == Type::BOTTOM) {
 325       continue;
 326     }
 327     // Construct code to access the appropriate local.
 328     Node* value = fetch_interpreter_state(index, type, locals_addr, osr_buf);
 329     set_local(index, value);
 330   }
 331 
 332   // Extract the needed stack entries from the interpreter frame.
 333   for (index = 0; index < sp(); index++) {
 334     const Type *type = osr_block->stack_type_at(index);
 335     if (type != Type::TOP) {
 336       // Currently the compiler bails out when attempting to on stack replace
 337       // at a bci with a non-empty stack.  We should not reach here.
 338       ShouldNotReachHere();
 339     }
 340   }
 341 
 342   // End the OSR migration
 343   make_runtime_call(RC_LEAF, OptoRuntime::osr_end_Type(),
 344                     CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),
 345                     "OSR_migration_end", TypeRawPtr::BOTTOM,
 346                     osr_buf);
 347 
 348   // Now that the interpreter state is loaded, make sure it will match
 349   // at execution time what the compiler is expecting now:
 350   SafePointNode* bad_type_exit = clone_map();
 351   bad_type_exit->set_control(new RegionNode(1));
 352 
 353   assert(osr_block->flow()->jsrs()->size() == 0, "should be no jsrs live at osr point");
 354   for (index = 0; index < max_locals; index++) {
 355     if (stopped())  break;
 356     Node* l = local(index);
 357     if (l->is_top())  continue;  // nothing here
 358     const Type *type = osr_block->local_type_at(index);
 359     if (type->isa_oopptr() != nullptr) {
 360       if (!live_oops.at(index)) {
 361         // skip type check for dead oops
 362         continue;
 363       }
 364     }
 365     if (osr_block->flow()->local_type_at(index)->is_return_address()) {
 366       // In our current system it's illegal for jsr addresses to be
 367       // live into an OSR entry point because the compiler performs
 368       // inlining of jsrs.  ciTypeFlow has a bailout that detect this
 369       // case and aborts the compile if addresses are live into an OSR
 370       // entry point.  Because of that we can assume that any address
 371       // locals at the OSR entry point are dead.  Method liveness
 372       // isn't precise enough to figure out that they are dead in all
 373       // cases so simply skip checking address locals all
 374       // together. Any type check is guaranteed to fail since the
 375       // interpreter type is the result of a load which might have any
 376       // value and the expected type is a constant.
 377       continue;
 378     }
 379     const TypeKlassPtr* klass_type = nullptr;
 380     if (type->isa_oopptr()) {
 381       klass_type = TypeKlassPtr::make(osr_block->flow()->local_type_at(index)->unwrap()->as_klass(), Type::ignore_interfaces);
 382       klass_type = klass_type->try_improve();
 383     }
 384     bool is_early_larval = osr_block->flow()->local_type_at(index)->is_early_larval();
 385     set_local(index, check_interpreter_type(l, type, klass_type, bad_type_exit, is_early_larval));
 386   }
 387 
 388   for (index = 0; index < sp(); index++) {
 389     if (stopped())  break;
 390     Node* l = stack(index);
 391     if (l->is_top())  continue;  // nothing here
 392     const Type* type = osr_block->stack_type_at(index);
 393     const TypeKlassPtr* klass_type = nullptr;
 394     if (type->isa_oopptr()) {
 395       klass_type = TypeKlassPtr::make(osr_block->flow()->stack_type_at(index)->unwrap()->as_klass(), Type::ignore_interfaces);
 396       klass_type = klass_type->try_improve();
 397     }
 398     bool is_early_larval = osr_block->flow()->stack_type_at(index)->is_early_larval();
 399     set_stack(index, check_interpreter_type(l, type, klass_type, bad_type_exit, is_early_larval));
 400   }
 401 
 402   if (bad_type_exit->control()->req() > 1) {
 403     // Build an uncommon trap here, if any inputs can be unexpected.
 404     bad_type_exit->set_control(_gvn.transform( bad_type_exit->control() ));
 405     record_for_igvn(bad_type_exit->control());
 406     SafePointNode* types_are_good = map();
 407     set_map(bad_type_exit);
 408     // The unexpected type happens because a new edge is active
 409     // in the CFG, which typeflow had previously ignored.
 410     // E.g., Object x = coldAtFirst() && notReached()? "str": new Integer(123).
 411     // This x will be typed as Integer if notReached is not yet linked.
 412     // It could also happen due to a problem in ciTypeFlow analysis.
 413     uncommon_trap(Deoptimization::Reason_constraint,
 414                   Deoptimization::Action_reinterpret);
 415     set_map(types_are_good);
 416   }
 417 }
 418 
 419 //------------------------------Parse------------------------------------------
 420 // Main parser constructor.
 421 Parse::Parse(JVMState* caller, ciMethod* parse_method, float expected_uses)
 422   : _exits(caller)
 423 {
 424   // Init some variables
 425   _caller = caller;
 426   _method = parse_method;
 427   _expected_uses = expected_uses;
 428   _depth = 1 + (caller->has_method() ? caller->depth() : 0);
 429   _wrote_final = false;
 430   _wrote_volatile = false;
 431   _wrote_stable = false;
 432   _wrote_fields = false;
 433   _alloc_with_final_or_stable = nullptr;
 434   _block = nullptr;
 435   _first_return = true;
 436   _replaced_nodes_for_exceptions = false;
 437   _new_idx = C->unique();
 438   DEBUG_ONLY(_entry_bci = UnknownBci);
 439   DEBUG_ONLY(_block_count = -1);
 440   DEBUG_ONLY(_blocks = (Block*)-1);
 441 #ifndef PRODUCT
 442   if (PrintCompilation || PrintOpto) {
 443     // Make sure I have an inline tree, so I can print messages about it.
 444     InlineTree::find_subtree_from_root(C->ilt(), caller, parse_method);
 445   }
 446   _max_switch_depth = 0;
 447   _est_switch_depth = 0;
 448 #endif
 449 
 450   if (parse_method->has_reserved_stack_access()) {
 451     C->set_has_reserved_stack_access(true);
 452   }
 453 
 454   if (parse_method->is_synchronized() || parse_method->has_monitor_bytecodes()) {
 455     C->set_has_monitors(true);
 456   }
 457 
 458   if (parse_method->is_scoped()) {
 459     C->set_has_scoped_access(true);
 460   }
 461 
 462   _iter.reset_to_method(method());
 463   C->set_has_loops(C->has_loops() || method()->has_loops());
 464 
 465   if (_expected_uses <= 0) {
 466     _prof_factor = 1;
 467   } else {
 468     float prof_total = parse_method->interpreter_invocation_count();
 469     if (prof_total <= _expected_uses) {
 470       _prof_factor = 1;
 471     } else {
 472       _prof_factor = _expected_uses / prof_total;
 473     }
 474   }
 475 
 476   CompileLog* log = C->log();
 477   if (log != nullptr) {
 478     log->begin_head("parse method='%d' uses='%f'",
 479                     log->identify(parse_method), expected_uses);
 480     if (depth() == 1 && C->is_osr_compilation()) {
 481       log->print(" osr_bci='%d'", C->entry_bci());
 482     }
 483     log->stamp();
 484     log->end_head();
 485   }
 486 
 487   // Accumulate deoptimization counts.
 488   // (The range_check and store_check counts are checked elsewhere.)
 489   ciMethodData* md = method()->method_data();
 490   for (uint reason = 0; reason < md->trap_reason_limit(); reason++) {
 491     uint md_count = md->trap_count(reason);
 492     if (md_count != 0) {
 493       if (md_count >= md->trap_count_limit()) {
 494         md_count = md->trap_count_limit() + md->overflow_trap_count();
 495       }
 496       uint total_count = C->trap_count(reason);
 497       uint old_count   = total_count;
 498       total_count += md_count;
 499       // Saturate the add if it overflows.
 500       if (total_count < old_count || total_count < md_count)
 501         total_count = (uint)-1;
 502       C->set_trap_count(reason, total_count);
 503       if (log != nullptr)
 504         log->elem("observe trap='%s' count='%d' total='%d'",
 505                   Deoptimization::trap_reason_name(reason),
 506                   md_count, total_count);
 507     }
 508   }
 509   // Accumulate total sum of decompilations, also.
 510   C->set_decompile_count(C->decompile_count() + md->decompile_count());
 511 
 512   if (log != nullptr && method()->has_exception_handlers()) {
 513     log->elem("observe that='has_exception_handlers'");
 514   }
 515 
 516   assert(InlineTree::check_can_parse(method()) == nullptr, "Can not parse this method, cutout earlier");
 517   assert(method()->has_balanced_monitors(), "Can not parse unbalanced monitors, cutout earlier");
 518 
 519   // Always register dependence if JVMTI is enabled, because
 520   // either breakpoint setting or hotswapping of methods may
 521   // cause deoptimization.
 522   if (C->env()->jvmti_can_hotswap_or_post_breakpoint()) {
 523     C->dependencies()->assert_evol_method(method());
 524   }
 525 
 526   NOT_PRODUCT(methods_seen++);
 527 
 528   // Do some special top-level things.
 529   if (depth() == 1 && C->is_osr_compilation()) {
 530     _tf = C->tf();     // the OSR entry type is different
 531     _entry_bci = C->entry_bci();
 532     _flow = method()->get_osr_flow_analysis(osr_bci());
 533   } else {
 534     _tf = TypeFunc::make(method());
 535     _entry_bci = InvocationEntryBci;
 536     _flow = method()->get_flow_analysis();
 537   }
 538 
 539   if (_flow->failing()) {
 540     // TODO Adding a trap due to an unloaded return type in ciTypeFlow::StateVector::do_invoke
 541     // can lead to this. Re-enable once 8284443 is fixed.
 542     //assert(false, "type flow analysis failed during parsing");
 543     C->record_method_not_compilable(_flow->failure_reason());
 544 #ifndef PRODUCT
 545       if (PrintOpto && (Verbose || WizardMode)) {
 546         if (is_osr_parse()) {
 547           tty->print_cr("OSR @%d type flow bailout: %s", _entry_bci, _flow->failure_reason());
 548         } else {
 549           tty->print_cr("type flow bailout: %s", _flow->failure_reason());
 550         }
 551         if (Verbose) {
 552           method()->print();
 553           method()->print_codes();
 554           _flow->print();
 555         }
 556       }
 557 #endif
 558   }
 559 
 560 #ifdef ASSERT
 561   if (depth() == 1) {
 562     assert(C->is_osr_compilation() == this->is_osr_parse(), "OSR in sync");
 563   } else {
 564     assert(!this->is_osr_parse(), "no recursive OSR");
 565   }
 566 #endif
 567 
 568 #ifndef PRODUCT
 569   if (_flow->has_irreducible_entry()) {
 570     C->set_parsed_irreducible_loop(true);
 571   }
 572 
 573   methods_parsed++;
 574   // add method size here to guarantee that inlined methods are added too
 575   if (CITime)
 576     _total_bytes_compiled += method()->code_size();
 577 
 578   show_parse_info();
 579 #endif
 580 
 581   if (failing()) {
 582     if (log)  log->done("parse");
 583     return;
 584   }
 585 
 586   gvn().transform(top());
 587 
 588   // Import the results of the ciTypeFlow.
 589   init_blocks();
 590 
 591   // Merge point for all normal exits
 592   build_exits();
 593 
 594   // Setup the initial JVM state map.
 595   SafePointNode* entry_map = create_entry_map();
 596 
 597   // Check for bailouts during map initialization
 598   if (failing() || entry_map == nullptr) {
 599     if (log)  log->done("parse");
 600     return;
 601   }
 602 
 603   Node_Notes* caller_nn = C->default_node_notes();
 604   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
 605   if (DebugInlinedCalls || depth() == 1) {
 606     C->set_default_node_notes(make_node_notes(caller_nn));
 607   }
 608 
 609   if (is_osr_parse()) {
 610     Node* osr_buf = entry_map->in(TypeFunc::Parms+0);
 611     entry_map->set_req(TypeFunc::Parms+0, top());
 612     set_map(entry_map);
 613     load_interpreter_state(osr_buf);
 614   } else {
 615     set_map(entry_map);
 616     do_method_entry();
 617   }
 618 
 619   if (depth() == 1 && !failing()) {
 620     if (C->clinit_barrier_on_entry()) {
 621       // Add check to deoptimize the nmethod once the holder class is fully initialized
 622       clinit_deopt();
 623     }
 624   }
 625 
 626   // Check for bailouts during method entry.
 627   if (failing()) {
 628     if (log)  log->done("parse");
 629     C->set_default_node_notes(caller_nn);
 630     return;
 631   }
 632 
 633   // Handle inline type arguments
 634   int arg_size = method()->arg_size();
 635   for (int i = 0; i < arg_size; i++) {
 636     Node* parm = local(i);
 637     const Type* t = _gvn.type(parm);
 638     if (t->is_inlinetypeptr()) {
 639       // If the parameter is a value object, try to scalarize it if we know that it is unrestricted (not early larval)
 640       // Parameters are non-larval except the receiver of a constructor, which must be an early larval object.
 641       if (!(method()->is_object_constructor() && i == 0)) {
 642         // Create InlineTypeNode from the oop and replace the parameter
 643         Node* vt = InlineTypeNode::make_from_oop(this, parm, t->inline_klass());
 644         replace_in_map(parm, vt);
 645       }
 646     } else if (UseTypeSpeculation && (i == (arg_size - 1)) && !is_osr_parse() && method()->has_vararg() &&
 647                t->isa_aryptr() != nullptr && !t->is_aryptr()->is_null_free() && !t->is_aryptr()->is_flat() &&
 648                (!t->is_aryptr()->is_not_null_free() || !t->is_aryptr()->is_not_flat())) {
 649       // Speculate on varargs Object array being not null-free and not flat
 650       const TypePtr* spec_type = t->speculative();
 651       spec_type = (spec_type != nullptr && spec_type->isa_aryptr() != nullptr) ? spec_type : t->is_aryptr();
 652       spec_type = spec_type->remove_speculative()->is_aryptr()->cast_to_not_null_free()->cast_to_not_flat();
 653       spec_type = TypeOopPtr::make(TypePtr::BotPTR, Type::Offset::bottom, TypeOopPtr::InstanceBot, spec_type);
 654       Node* cast = _gvn.transform(new CheckCastPPNode(control(), parm, t->join_speculative(spec_type)));
 655       replace_in_map(parm, cast);
 656     }
 657   }
 658 
 659   entry_map = map();  // capture any changes performed by method setup code
 660   assert(jvms()->endoff() == map()->req(), "map matches JVMS layout");
 661 
 662   // We begin parsing as if we have just encountered a jump to the
 663   // method entry.
 664   Block* entry_block = start_block();
 665   assert(entry_block->start() == (is_osr_parse() ? osr_bci() : 0), "");
 666   set_map_clone(entry_map);
 667   merge_common(entry_block, entry_block->next_path_num());
 668 
 669 #ifndef PRODUCT
 670   BytecodeParseHistogram *parse_histogram_obj = new (C->env()->arena()) BytecodeParseHistogram(this, C);
 671   set_parse_histogram( parse_histogram_obj );
 672 #endif
 673 
 674   // Parse all the basic blocks.
 675   do_all_blocks();
 676 
 677   // Check for bailouts during conversion to graph
 678   if (failing()) {
 679     if (log)  log->done("parse");
 680     return;
 681   }
 682 
 683   // Fix up all exiting control flow.
 684   set_map(entry_map);
 685   do_exits();
 686 
 687   // Only reset this now, to make sure that debug information emitted
 688   // for exiting control flow still refers to the inlined method.
 689   C->set_default_node_notes(caller_nn);
 690 
 691   if (log)  log->done("parse nodes='%d' live='%d' memory='%zu'",
 692                       C->unique(), C->live_nodes(), C->node_arena()->used());
 693 }
 694 
 695 //---------------------------do_all_blocks-------------------------------------
 696 void Parse::do_all_blocks() {
 697   bool has_irreducible = flow()->has_irreducible_entry();
 698 
 699   // Walk over all blocks in Reverse Post-Order.
 700   while (true) {
 701     bool progress = false;
 702     for (int rpo = 0; rpo < block_count(); rpo++) {
 703       Block* block = rpo_at(rpo);
 704 
 705       if (block->is_parsed()) continue;
 706 
 707       if (!block->is_merged()) {
 708         // Dead block, no state reaches this block
 709         continue;
 710       }
 711 
 712       // Prepare to parse this block.
 713       load_state_from(block);
 714 
 715       if (stopped()) {
 716         // Block is dead.
 717         continue;
 718       }
 719 
 720       NOT_PRODUCT(blocks_parsed++);
 721 
 722       progress = true;
 723       if (block->is_loop_head() || block->is_handler() || (has_irreducible && !block->is_ready())) {
 724         // Not all preds have been parsed.  We must build phis everywhere.
 725         // (Note that dead locals do not get phis built, ever.)
 726         ensure_phis_everywhere();
 727 
 728         if (block->is_SEL_head()) {
 729           // Add predicate to single entry (not irreducible) loop head.
 730           assert(!block->has_merged_backedge(), "only entry paths should be merged for now");
 731           // Predicates may have been added after a dominating if
 732           if (!block->has_predicates()) {
 733             // Need correct bci for predicate.
 734             // It is fine to set it here since do_one_block() will set it anyway.
 735             set_parse_bci(block->start());
 736             add_parse_predicates();
 737           }
 738           // Add new region for back branches.
 739           int edges = block->pred_count() - block->preds_parsed() + 1; // +1 for original region
 740           RegionNode *r = new RegionNode(edges+1);
 741           _gvn.set_type(r, Type::CONTROL);
 742           record_for_igvn(r);
 743           r->init_req(edges, control());
 744           set_control(r);
 745           block->copy_irreducible_status_to(r, jvms());
 746           // Add new phis.
 747           ensure_phis_everywhere();
 748         }
 749 
 750         // Leave behind an undisturbed copy of the map, for future merges.
 751         set_map(clone_map());
 752       }
 753 
 754       if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) {
 755         // In the absence of irreducible loops, the Region and Phis
 756         // associated with a merge that doesn't involve a backedge can
 757         // be simplified now since the RPO parsing order guarantees
 758         // that any path which was supposed to reach here has already
 759         // been parsed or must be dead.
 760         Node* c = control();
 761         Node* result = _gvn.transform(control());
 762         if (c != result && TraceOptoParse) {
 763           tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx);
 764         }
 765         if (result != top()) {
 766           record_for_igvn(result);
 767         }
 768       }
 769 
 770       // Parse the block.
 771       do_one_block();
 772 
 773       // Check for bailouts.
 774       if (failing())  return;
 775     }
 776 
 777     // with irreducible loops multiple passes might be necessary to parse everything
 778     if (!has_irreducible || !progress) {
 779       break;
 780     }
 781   }
 782 
 783 #ifndef PRODUCT
 784   blocks_seen += block_count();
 785 
 786   // Make sure there are no half-processed blocks remaining.
 787   // Every remaining unprocessed block is dead and may be ignored now.
 788   for (int rpo = 0; rpo < block_count(); rpo++) {
 789     Block* block = rpo_at(rpo);
 790     if (!block->is_parsed()) {
 791       if (TraceOptoParse) {
 792         tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start());
 793       }
 794       assert(!block->is_merged(), "no half-processed blocks");
 795     }
 796   }
 797 #endif
 798 }
 799 
 800 static Node* mask_int_value(Node* v, BasicType bt, PhaseGVN* gvn) {
 801   switch (bt) {
 802   case T_BYTE:
 803     v = gvn->transform(new LShiftINode(v, gvn->intcon(24)));
 804     v = gvn->transform(new RShiftINode(v, gvn->intcon(24)));
 805     break;
 806   case T_SHORT:
 807     v = gvn->transform(new LShiftINode(v, gvn->intcon(16)));
 808     v = gvn->transform(new RShiftINode(v, gvn->intcon(16)));
 809     break;
 810   case T_CHAR:
 811     v = gvn->transform(new AndINode(v, gvn->intcon(0xFFFF)));
 812     break;
 813   case T_BOOLEAN:
 814     v = gvn->transform(new AndINode(v, gvn->intcon(0x1)));
 815     break;
 816   default:
 817     break;
 818   }
 819   return v;
 820 }
 821 
 822 //-------------------------------build_exits----------------------------------
 823 // Build normal and exceptional exit merge points.
 824 void Parse::build_exits() {
 825   // make a clone of caller to prevent sharing of side-effects
 826   _exits.set_map(_exits.clone_map());
 827   _exits.clean_stack(_exits.sp());
 828   _exits.sync_jvms();
 829 
 830   RegionNode* region = new RegionNode(1);
 831   record_for_igvn(region);
 832   gvn().set_type_bottom(region);
 833   _exits.set_control(region);
 834 
 835   // Note:  iophi and memphi are not transformed until do_exits.
 836   Node* iophi  = new PhiNode(region, Type::ABIO);
 837   Node* memphi = new PhiNode(region, Type::MEMORY, TypePtr::BOTTOM);
 838   gvn().set_type_bottom(iophi);
 839   gvn().set_type_bottom(memphi);
 840   _exits.set_i_o(iophi);
 841   _exits.set_all_memory(memphi);
 842 
 843   // Add a return value to the exit state.  (Do not push it yet.)
 844   if (tf()->range_sig()->cnt() > TypeFunc::Parms) {
 845     const Type* ret_type = tf()->range_sig()->field_at(TypeFunc::Parms);
 846     if (ret_type->isa_int()) {
 847       BasicType ret_bt = method()->return_type()->basic_type();
 848       if (ret_bt == T_BOOLEAN ||
 849           ret_bt == T_CHAR ||
 850           ret_bt == T_BYTE ||
 851           ret_bt == T_SHORT) {
 852         ret_type = TypeInt::INT;
 853       }
 854     }
 855 
 856     // Don't "bind" an unloaded return klass to the ret_phi. If the klass
 857     // becomes loaded during the subsequent parsing, the loaded and unloaded
 858     // types will not join when we transform and push in do_exits().
 859     const TypeOopPtr* ret_oop_type = ret_type->isa_oopptr();
 860     if (ret_oop_type && !ret_oop_type->is_loaded()) {
 861       ret_type = TypeOopPtr::BOTTOM;
 862     }
 863     int         ret_size = type2size[ret_type->basic_type()];
 864     Node*       ret_phi  = new PhiNode(region, ret_type);
 865     gvn().set_type_bottom(ret_phi);
 866     _exits.ensure_stack(ret_size);
 867     assert((int)(tf()->range_sig()->cnt() - TypeFunc::Parms) == ret_size, "good tf range");
 868     assert(method()->return_type()->size() == ret_size, "tf agrees w/ method");
 869     _exits.set_argument(0, ret_phi);  // here is where the parser finds it
 870     // Note:  ret_phi is not yet pushed, until do_exits.
 871   }
 872 }
 873 
 874 //----------------------------build_start_state-------------------------------
 875 // Construct a state which contains only the incoming arguments from an
 876 // unknown caller.  The method & bci will be null & InvocationEntryBci.
 877 JVMState* Compile::build_start_state(StartNode* start, const TypeFunc* tf) {
 878   int        arg_size = tf->domain_sig()->cnt();
 879   int        max_size = MAX2(arg_size, (int)tf->range_cc()->cnt());
 880   JVMState*  jvms     = new (this) JVMState(max_size - TypeFunc::Parms);
 881   SafePointNode* map  = new SafePointNode(max_size, jvms);
 882   jvms->set_map(map);
 883   record_for_igvn(map);
 884   assert(arg_size == TypeFunc::Parms + (is_osr_compilation() ? 1 : method()->arg_size()), "correct arg_size");
 885   Node_Notes* old_nn = default_node_notes();
 886   if (old_nn != nullptr && has_method()) {
 887     Node_Notes* entry_nn = old_nn->clone(this);
 888     JVMState* entry_jvms = new(this) JVMState(method(), old_nn->jvms());
 889     entry_jvms->set_offsets(0);
 890     entry_jvms->set_bci(entry_bci());
 891     entry_nn->set_jvms(entry_jvms);
 892     set_default_node_notes(entry_nn);
 893   }
 894   PhaseGVN& gvn = *initial_gvn();
 895   uint i = 0;
 896   int arg_num = 0;
 897   for (uint j = 0; i < (uint)arg_size; i++) {
 898     const Type* t = tf->domain_sig()->field_at(i);
 899     Node* parm = nullptr;
 900     if (t->is_inlinetypeptr() && method()->is_scalarized_arg(arg_num)) {
 901       // Inline type arguments are not passed by reference: we get an argument per
 902       // field of the inline type. Build InlineTypeNodes from the inline type arguments.
 903       GraphKit kit(jvms, &gvn);
 904       kit.set_control(map->control());
 905       Node* old_mem = map->memory();
 906       // Use immutable memory for inline type loads and restore it below
 907       kit.set_all_memory(C->immutable_memory());
 908       parm = InlineTypeNode::make_from_multi(&kit, start, t->inline_klass(), j, /* in= */ true, /* null_free= */ !t->maybe_null());
 909       map->set_control(kit.control());
 910       map->set_memory(old_mem);
 911     } else {
 912       parm = gvn.transform(new ParmNode(start, j++));
 913     }
 914     map->init_req(i, parm);
 915     // Record all these guys for later GVN.
 916     record_for_igvn(parm);
 917     if (i >= TypeFunc::Parms && t != Type::HALF) {
 918       arg_num++;
 919     }
 920   }
 921   for (; i < map->req(); i++) {
 922     map->init_req(i, top());
 923   }
 924   assert(jvms->argoff() == TypeFunc::Parms, "parser gets arguments here");
 925   set_default_node_notes(old_nn);
 926   return jvms;
 927 }
 928 
 929 //-----------------------------make_node_notes---------------------------------
 930 Node_Notes* Parse::make_node_notes(Node_Notes* caller_nn) {
 931   if (caller_nn == nullptr)  return nullptr;
 932   Node_Notes* nn = caller_nn->clone(C);
 933   JVMState* caller_jvms = nn->jvms();
 934   JVMState* jvms = new (C) JVMState(method(), caller_jvms);
 935   jvms->set_offsets(0);
 936   jvms->set_bci(_entry_bci);
 937   nn->set_jvms(jvms);
 938   return nn;
 939 }
 940 
 941 
 942 //--------------------------return_values--------------------------------------
 943 void Compile::return_values(JVMState* jvms) {
 944   GraphKit kit(jvms);
 945   Node* ret = new ReturnNode(TypeFunc::Parms,
 946                              kit.control(),
 947                              kit.i_o(),
 948                              kit.reset_memory(),
 949                              kit.frameptr(),
 950                              kit.returnadr());
 951   // Add zero or 1 return values
 952   int ret_size = tf()->range_sig()->cnt() - TypeFunc::Parms;
 953   if (ret_size > 0) {
 954     kit.inc_sp(-ret_size);  // pop the return value(s)
 955     kit.sync_jvms();
 956     Node* res = kit.argument(0);
 957     if (tf()->returns_inline_type_as_fields()) {
 958       // Multiple return values (inline type fields): add as many edges
 959       // to the Return node as returned values.
 960       InlineTypeNode* vt = res->as_InlineType();
 961       ret->add_req_batch(nullptr, tf()->range_cc()->cnt() - TypeFunc::Parms);
 962       if (vt->is_allocated(&kit.gvn()) && !StressCallingConvention) {
 963         ret->init_req(TypeFunc::Parms, vt);
 964       } else {
 965         // Return the tagged klass pointer to signal scalarization to the caller
 966         Node* tagged_klass = vt->tagged_klass(kit.gvn());
 967         // Return null if the inline type is null (null marker field is not set)
 968         Node* conv   = kit.gvn().transform(new ConvI2LNode(vt->get_null_marker()));
 969         Node* shl    = kit.gvn().transform(new LShiftLNode(conv, kit.intcon(63)));
 970         Node* shr    = kit.gvn().transform(new RShiftLNode(shl, kit.intcon(63)));
 971         tagged_klass = kit.gvn().transform(new AndLNode(tagged_klass, shr));
 972         ret->init_req(TypeFunc::Parms, tagged_klass);
 973       }
 974       uint idx = TypeFunc::Parms + 1;
 975       vt->pass_fields(&kit, ret, idx, false, false);
 976     } else {
 977       ret->add_req(res);
 978       // Note:  The second dummy edge is not needed by a ReturnNode.
 979     }
 980   }
 981   // bind it to root
 982   root()->add_req(ret);
 983   record_for_igvn(ret);
 984   initial_gvn()->transform(ret);
 985 }
 986 
 987 //------------------------rethrow_exceptions-----------------------------------
 988 // Bind all exception states in the list into a single RethrowNode.
 989 void Compile::rethrow_exceptions(JVMState* jvms) {
 990   GraphKit kit(jvms);
 991   if (!kit.has_exceptions())  return;  // nothing to generate
 992   // Load my combined exception state into the kit, with all phis transformed:
 993   SafePointNode* ex_map = kit.combine_and_pop_all_exception_states();
 994   Node* ex_oop = kit.use_exception_state(ex_map);
 995   RethrowNode* exit = new RethrowNode(kit.control(),
 996                                       kit.i_o(), kit.reset_memory(),
 997                                       kit.frameptr(), kit.returnadr(),
 998                                       // like a return but with exception input
 999                                       ex_oop);
1000   // bind to root
1001   root()->add_req(exit);
1002   record_for_igvn(exit);
1003   initial_gvn()->transform(exit);
1004 }
1005 
1006 //---------------------------do_exceptions-------------------------------------
1007 // Process exceptions arising from the current bytecode.
1008 // Send caught exceptions to the proper handler within this method.
1009 // Unhandled exceptions feed into _exit.
1010 void Parse::do_exceptions() {
1011   if (!has_exceptions())  return;
1012 
1013   if (failing()) {
1014     // Pop them all off and throw them away.
1015     while (pop_exception_state() != nullptr) ;
1016     return;
1017   }
1018 
1019   PreserveJVMState pjvms(this, false);
1020 
1021   SafePointNode* ex_map;
1022   while ((ex_map = pop_exception_state()) != nullptr) {
1023     if (!method()->has_exception_handlers()) {
1024       // Common case:  Transfer control outward.
1025       // Doing it this early allows the exceptions to common up
1026       // even between adjacent method calls.
1027       throw_to_exit(ex_map);
1028     } else {
1029       // Have to look at the exception first.
1030       assert(stopped(), "catch_inline_exceptions trashes the map");
1031       catch_inline_exceptions(ex_map);
1032       stop_and_kill_map();      // we used up this exception state; kill it
1033     }
1034   }
1035 
1036   // We now return to our regularly scheduled program:
1037 }
1038 
1039 //---------------------------throw_to_exit-------------------------------------
1040 // Merge the given map into an exception exit from this method.
1041 // The exception exit will handle any unlocking of receiver.
1042 // The ex_oop must be saved within the ex_map, unlike merge_exception.
1043 void Parse::throw_to_exit(SafePointNode* ex_map) {
1044   // Pop the JVMS to (a copy of) the caller.
1045   GraphKit caller;
1046   caller.set_map_clone(_caller->map());
1047   caller.set_bci(_caller->bci());
1048   caller.set_sp(_caller->sp());
1049   // Copy out the standard machine state:
1050   for (uint i = 0; i < TypeFunc::Parms; i++) {
1051     caller.map()->set_req(i, ex_map->in(i));
1052   }
1053   if (ex_map->has_replaced_nodes()) {
1054     _replaced_nodes_for_exceptions = true;
1055   }
1056   caller.map()->transfer_replaced_nodes_from(ex_map, _new_idx);
1057   // ...and the exception:
1058   Node*          ex_oop        = saved_ex_oop(ex_map);
1059   SafePointNode* caller_ex_map = caller.make_exception_state(ex_oop);
1060   // Finally, collect the new exception state in my exits:
1061   _exits.add_exception_state(caller_ex_map);
1062 }
1063 
1064 //------------------------------do_exits---------------------------------------
1065 void Parse::do_exits() {
1066   set_parse_bci(InvocationEntryBci);
1067 
1068   // Now peephole on the return bits
1069   Node* region = _exits.control();
1070   _exits.set_control(gvn().transform(region));
1071 
1072   Node* iophi = _exits.i_o();
1073   _exits.set_i_o(gvn().transform(iophi));
1074 
1075   // Figure out if we need to emit the trailing barrier. The barrier is only
1076   // needed in the constructors, and only in three cases:
1077   //
1078   // 1. The constructor wrote a final or a @Stable field. All these
1079   //    initializations must be ordered before any code after the constructor
1080   //    publishes the reference to the newly constructed object. Rather
1081   //    than wait for the publication, we simply block the writes here.
1082   //    Rather than put a barrier on only those writes which are required
1083   //    to complete, we force all writes to complete.
1084   //
1085   // 2. Experimental VM option is used to force the barrier if any field
1086   //    was written out in the constructor.
1087   //
1088   // 3. On processors which are not CPU_MULTI_COPY_ATOMIC (e.g. PPC64),
1089   //    support_IRIW_for_not_multiple_copy_atomic_cpu selects that
1090   //    MemBarVolatile is used before volatile load instead of after volatile
1091   //    store, so there's no barrier after the store.
1092   //    We want to guarantee the same behavior as on platforms with total store
1093   //    order, although this is not required by the Java memory model.
1094   //    In this case, we want to enforce visibility of volatile field
1095   //    initializations which are performed in constructors.
1096   //    So as with finals, we add a barrier here.
1097   //
1098   // "All bets are off" unless the first publication occurs after a
1099   // normal return from the constructor.  We do not attempt to detect
1100   // such unusual early publications.  But no barrier is needed on
1101   // exceptional returns, since they cannot publish normally.
1102   //
1103   if ((method()->is_object_constructor() || method()->is_class_initializer()) &&
1104        (wrote_final() || wrote_stable() ||
1105          (AlwaysSafeConstructors && wrote_fields()) ||
1106          (support_IRIW_for_not_multiple_copy_atomic_cpu && wrote_volatile()))) {
1107     Node* recorded_alloc = alloc_with_final_or_stable();
1108     _exits.insert_mem_bar(UseStoreStoreForCtor ? Op_MemBarStoreStore : Op_MemBarRelease,
1109                           recorded_alloc);
1110 
1111     // If Memory barrier is created for final fields write
1112     // and allocation node does not escape the initialize method,
1113     // then barrier introduced by allocation node can be removed.
1114     if (DoEscapeAnalysis && (recorded_alloc != nullptr)) {
1115       AllocateNode* alloc = AllocateNode::Ideal_allocation(recorded_alloc);
1116       alloc->compute_MemBar_redundancy(method());
1117     }
1118     if (PrintOpto && (Verbose || WizardMode)) {
1119       method()->print_name();
1120       tty->print_cr(" writes finals/@Stable and needs a memory barrier");
1121     }
1122   }
1123 
1124   for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) {
1125     // transform each slice of the original memphi:
1126     mms.set_memory(_gvn.transform(mms.memory()));
1127   }
1128   // Clean up input MergeMems created by transforming the slices
1129   _gvn.transform(_exits.merged_memory());
1130 
1131   if (tf()->range_sig()->cnt() > TypeFunc::Parms) {
1132     const Type* ret_type = tf()->range_sig()->field_at(TypeFunc::Parms);
1133     Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
1134     if (!_exits.control()->is_top() && _gvn.type(ret_phi)->empty()) {
1135       // If the type we set for the ret_phi in build_exits() is too optimistic and
1136       // the ret_phi is top now, there's an extremely small chance that it may be due to class
1137       // loading.  It could also be due to an error, so mark this method as not compilable because
1138       // otherwise this could lead to an infinite compile loop.
1139       // In any case, this code path is rarely (and never in my testing) reached.
1140       C->record_method_not_compilable("Can't determine return type.");
1141       return;
1142     }
1143     if (ret_type->isa_int()) {
1144       BasicType ret_bt = method()->return_type()->basic_type();
1145       ret_phi = mask_int_value(ret_phi, ret_bt, &_gvn);
1146     }
1147     _exits.push_node(ret_type->basic_type(), ret_phi);
1148   }
1149 
1150   // Note:  Logic for creating and optimizing the ReturnNode is in Compile.
1151 
1152   // Unlock along the exceptional paths.
1153   // This is done late so that we can common up equivalent exceptions
1154   // (e.g., null checks) arising from multiple points within this method.
1155   // See GraphKit::add_exception_state, which performs the commoning.
1156   bool do_synch = method()->is_synchronized();
1157 
1158   // record exit from a method if compiled while Dtrace is turned on.
1159   if (do_synch || C->env()->dtrace_method_probes() || _replaced_nodes_for_exceptions) {
1160     // First move the exception list out of _exits:
1161     GraphKit kit(_exits.transfer_exceptions_into_jvms());
1162     SafePointNode* normal_map = kit.map();  // keep this guy safe
1163     // Now re-collect the exceptions into _exits:
1164     SafePointNode* ex_map;
1165     while ((ex_map = kit.pop_exception_state()) != nullptr) {
1166       Node* ex_oop = kit.use_exception_state(ex_map);
1167       // Force the exiting JVM state to have this method at InvocationEntryBci.
1168       // The exiting JVM state is otherwise a copy of the calling JVMS.
1169       JVMState* caller = kit.jvms();
1170       JVMState* ex_jvms = caller->clone_shallow(C);
1171       ex_jvms->bind_map(kit.clone_map());
1172       ex_jvms->set_bci(   InvocationEntryBci);
1173       kit.set_jvms(ex_jvms);
1174       if (do_synch) {
1175         // Add on the synchronized-method box/object combo
1176         kit.map()->push_monitor(_synch_lock);
1177         // Unlock!
1178         kit.shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
1179       }
1180       if (C->env()->dtrace_method_probes()) {
1181         kit.make_dtrace_method_exit(method());
1182       }
1183       if (_replaced_nodes_for_exceptions) {
1184         kit.map()->apply_replaced_nodes(_new_idx);
1185       }
1186       // Done with exception-path processing.
1187       ex_map = kit.make_exception_state(ex_oop);
1188       assert(ex_jvms->same_calls_as(ex_map->jvms()), "sanity");
1189       // Pop the last vestige of this method:
1190       caller->clone_shallow(C)->bind_map(ex_map);
1191       _exits.push_exception_state(ex_map);
1192     }
1193     assert(_exits.map() == normal_map, "keep the same return state");
1194   }
1195 
1196   {
1197     // Capture very early exceptions (receiver null checks) from caller JVMS
1198     GraphKit caller(_caller);
1199     SafePointNode* ex_map;
1200     while ((ex_map = caller.pop_exception_state()) != nullptr) {
1201       _exits.add_exception_state(ex_map);
1202     }
1203   }
1204   _exits.map()->apply_replaced_nodes(_new_idx);
1205 }
1206 
1207 //-----------------------------create_entry_map-------------------------------
1208 // Initialize our parser map to contain the types at method entry.
1209 // For OSR, the map contains a single RawPtr parameter.
1210 // Initial monitor locking for sync. methods is performed by do_method_entry.
1211 SafePointNode* Parse::create_entry_map() {
1212   // Check for really stupid bail-out cases.
1213   uint len = TypeFunc::Parms + method()->max_locals() + method()->max_stack();
1214   if (len >= 32760) {
1215     // Bailout expected, this is a very rare edge case.
1216     C->record_method_not_compilable("too many local variables");
1217     return nullptr;
1218   }
1219 
1220   // clear current replaced nodes that are of no use from here on (map was cloned in build_exits).
1221   _caller->map()->delete_replaced_nodes();
1222 
1223   // If this is an inlined method, we may have to do a receiver null check.
1224   if (_caller->has_method() && is_normal_parse() && !method()->is_static()) {
1225     GraphKit kit(_caller);
1226     Node* receiver = kit.argument(0);
1227     Node* null_free = kit.null_check_receiver_before_call(method());
1228     _caller = kit.transfer_exceptions_into_jvms();
1229 
1230     if (kit.stopped()) {
1231       _exits.add_exception_states_from(_caller);
1232       _exits.set_jvms(_caller);
1233       return nullptr;
1234     }
1235   }
1236 
1237   assert(method() != nullptr, "parser must have a method");
1238 
1239   // Create an initial safepoint to hold JVM state during parsing
1240   JVMState* jvms = new (C) JVMState(method(), _caller->has_method() ? _caller : nullptr);
1241   set_map(new SafePointNode(len, jvms));
1242 
1243   // Capture receiver info for compiled lambda forms.
1244   if (method()->is_compiled_lambda_form()) {
1245     ciInstance* recv_info = _caller->compute_receiver_info(method());
1246     jvms->set_receiver_info(recv_info);
1247   }
1248 
1249   jvms->set_map(map());
1250   record_for_igvn(map());
1251   assert(jvms->endoff() == len, "correct jvms sizing");
1252 
1253   SafePointNode* inmap = _caller->map();
1254   assert(inmap != nullptr, "must have inmap");
1255   // In case of null check on receiver above
1256   map()->transfer_replaced_nodes_from(inmap, _new_idx);
1257 
1258   uint i;
1259 
1260   // Pass thru the predefined input parameters.
1261   for (i = 0; i < TypeFunc::Parms; i++) {
1262     map()->init_req(i, inmap->in(i));
1263   }
1264 
1265   if (depth() == 1) {
1266     assert(map()->memory()->Opcode() == Op_Parm, "");
1267     // Insert the memory aliasing node
1268     set_all_memory(reset_memory());
1269   }
1270   assert(merged_memory(), "");
1271 
1272   // Now add the locals which are initially bound to arguments:
1273   uint arg_size = tf()->domain_sig()->cnt();
1274   ensure_stack(arg_size - TypeFunc::Parms);  // OSR methods have funny args
1275   for (i = TypeFunc::Parms; i < arg_size; i++) {
1276     map()->init_req(i, inmap->argument(_caller, i - TypeFunc::Parms));
1277   }
1278 
1279   // Clear out the rest of the map (locals and stack)
1280   for (i = arg_size; i < len; i++) {
1281     map()->init_req(i, top());
1282   }
1283 
1284   SafePointNode* entry_map = stop();
1285   return entry_map;
1286 }
1287 
1288 //-----------------------------do_method_entry--------------------------------
1289 // Emit any code needed in the pseudo-block before BCI zero.
1290 // The main thing to do is lock the receiver of a synchronized method.
1291 void Parse::do_method_entry() {
1292   set_parse_bci(InvocationEntryBci); // Pseudo-BCP
1293   set_sp(0);                         // Java Stack Pointer
1294 
1295   NOT_PRODUCT( count_compiled_calls(true/*at_method_entry*/, false/*is_inline*/); )
1296 
1297   // Check if we need a membar at the beginning of the java.lang.Object
1298   // constructor to satisfy the memory model for strict fields.
1299   if (Arguments::is_valhalla_enabled() && method()->intrinsic_id() == vmIntrinsics::_Object_init) {
1300     Node* receiver_obj = local(0);
1301     const TypeInstPtr* receiver_type = _gvn.type(receiver_obj)->isa_instptr();
1302     // If there's no exact type, check if the declared type has no implementors and add a dependency
1303     const TypeKlassPtr* klass_ptr = receiver_type->as_klass_type(/* try_for_exact= */ true);
1304     ciType* klass = klass_ptr->klass_is_exact() ? klass_ptr->exact_klass() : nullptr;
1305     if (klass != nullptr && klass->is_instance_klass()) {
1306       // Exact receiver type, check if there is a strict field
1307       ciInstanceKlass* holder = klass->as_instance_klass();
1308       for (int i = 0; i < holder->nof_nonstatic_fields(); i++) {
1309         ciField* field = holder->nonstatic_field_at(i);
1310         if (field->is_strict()) {
1311           // Found a strict field, a membar is needed
1312           AllocateNode* alloc = AllocateNode::Ideal_allocation(receiver_obj);
1313           insert_mem_bar(UseStoreStoreForCtor ? Op_MemBarStoreStore : Op_MemBarRelease, receiver_obj);
1314           if (DoEscapeAnalysis && (alloc != nullptr)) {
1315             alloc->compute_MemBar_redundancy(method());
1316           }
1317           break;
1318         }
1319       }
1320     } else if (klass == nullptr) {
1321       // We can't statically determine the type of the receiver and therefore need
1322       // to put a membar here because it could have a strict field.
1323       insert_mem_bar(UseStoreStoreForCtor ? Op_MemBarStoreStore : Op_MemBarRelease);
1324     }
1325   }
1326 
1327   if (C->env()->dtrace_method_probes()) {
1328     make_dtrace_method_entry(method());
1329   }
1330 
1331 #ifdef ASSERT
1332   // Narrow receiver type when it is too broad for the method being parsed.
1333   if (!method()->is_static()) {
1334     ciInstanceKlass* callee_holder = method()->holder();
1335     const Type* holder_type = TypeInstPtr::make(TypePtr::BotPTR, callee_holder, Type::trust_interfaces);
1336 
1337     Node* receiver_obj = local(0);
1338     const TypeInstPtr* receiver_type = _gvn.type(receiver_obj)->isa_instptr();
1339 
1340     if (receiver_type != nullptr && !receiver_type->higher_equal(holder_type)) {
1341       // Receiver should always be a subtype of callee holder.
1342       // But, since C2 type system doesn't properly track interfaces,
1343       // the invariant can't be expressed in the type system for default methods.
1344       // Example: for unrelated C <: I and D <: I, (C `meet` D) = Object </: I.
1345       assert(callee_holder->is_interface(), "missing subtype check");
1346 
1347       // Perform dynamic receiver subtype check against callee holder class w/ a halt on failure.
1348       Node* holder_klass = _gvn.makecon(TypeKlassPtr::make(callee_holder, Type::trust_interfaces));
1349       Node* not_subtype_ctrl = gen_subtype_check(receiver_obj, holder_klass);
1350       assert(!stopped(), "not a subtype");
1351 
1352       Node* halt = _gvn.transform(new HaltNode(not_subtype_ctrl, frameptr(), "failed receiver subtype check"));
1353       C->root()->add_req(halt);
1354     }
1355   }
1356 #endif // ASSERT
1357 
1358   // If the method is synchronized, we need to construct a lock node, attach
1359   // it to the Start node, and pin it there.
1360   if (method()->is_synchronized()) {
1361     // Insert a FastLockNode right after the Start which takes as arguments
1362     // the current thread pointer, the "this" pointer & the address of the
1363     // stack slot pair used for the lock.  The "this" pointer is a projection
1364     // off the start node, but the locking spot has to be constructed by
1365     // creating a ConLNode of 0, and boxing it with a BoxLockNode.  The BoxLockNode
1366     // becomes the second argument to the FastLockNode call.  The
1367     // FastLockNode becomes the new control parent to pin it to the start.
1368 
1369     // Setup Object Pointer
1370     Node *lock_obj = nullptr;
1371     if (method()->is_static()) {
1372       ciInstance* mirror = _method->holder()->java_mirror();
1373       const TypeInstPtr *t_lock = TypeInstPtr::make(mirror);
1374       lock_obj = makecon(t_lock);
1375     } else {                  // Else pass the "this" pointer,
1376       lock_obj = local(0);    // which is Parm0 from StartNode
1377       assert(!_gvn.type(lock_obj)->make_oopptr()->can_be_inline_type(), "can't be an inline type");
1378     }
1379     // Clear out dead values from the debug info.
1380     kill_dead_locals();
1381     // Build the FastLockNode
1382     _synch_lock = shared_lock(lock_obj);
1383     // Check for bailout in shared_lock
1384     if (failing()) { return; }
1385   }
1386 
1387   // Feed profiling data for parameters to the type system so it can
1388   // propagate it as speculative types
1389   record_profiled_parameters_for_speculation();
1390 }
1391 
1392 //------------------------------init_blocks------------------------------------
1393 // Initialize our parser map to contain the types/monitors at method entry.
1394 void Parse::init_blocks() {
1395   // Create the blocks.
1396   _block_count = flow()->block_count();
1397   _blocks = NEW_RESOURCE_ARRAY(Block, _block_count);
1398 
1399   // Initialize the structs.
1400   for (int rpo = 0; rpo < block_count(); rpo++) {
1401     Block* block = rpo_at(rpo);
1402     new(block) Block(this, rpo);
1403   }
1404 
1405   // Collect predecessor and successor information.
1406   for (int rpo = 0; rpo < block_count(); rpo++) {
1407     Block* block = rpo_at(rpo);
1408     block->init_graph(this);
1409   }
1410 }
1411 
1412 //-------------------------------init_node-------------------------------------
1413 Parse::Block::Block(Parse* outer, int rpo) : _live_locals() {
1414   _flow = outer->flow()->rpo_at(rpo);
1415   _pred_count = 0;
1416   _preds_parsed = 0;
1417   _count = 0;
1418   _is_parsed = false;
1419   _is_handler = false;
1420   _has_merged_backedge = false;
1421   _start_map = nullptr;
1422   _has_predicates = false;
1423   _num_successors = 0;
1424   _all_successors = 0;
1425   _successors = nullptr;
1426   assert(pred_count() == 0 && preds_parsed() == 0, "sanity");
1427   assert(!(is_merged() || is_parsed() || is_handler() || has_merged_backedge()), "sanity");
1428   assert(_live_locals.size() == 0, "sanity");
1429 
1430   // entry point has additional predecessor
1431   if (flow()->is_start())  _pred_count++;
1432   assert(flow()->is_start() == (this == outer->start_block()), "");
1433 }
1434 
1435 //-------------------------------init_graph------------------------------------
1436 void Parse::Block::init_graph(Parse* outer) {
1437   // Create the successor list for this parser block.
1438   GrowableArray<ciTypeFlow::Block*>* tfs = flow()->successors();
1439   GrowableArray<ciTypeFlow::Block*>* tfe = flow()->exceptions();
1440   int ns = tfs->length();
1441   int ne = tfe->length();
1442   _num_successors = ns;
1443   _all_successors = ns+ne;
1444   _successors = (ns+ne == 0) ? nullptr : NEW_RESOURCE_ARRAY(Block*, ns+ne);
1445   int p = 0;
1446   for (int i = 0; i < ns+ne; i++) {
1447     ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns);
1448     Block* block2 = outer->rpo_at(tf2->rpo());
1449     _successors[i] = block2;
1450 
1451     // Accumulate pred info for the other block, too.
1452     // Note: We also need to set _pred_count for exception blocks since they could
1453     // also have normal predecessors (reached without athrow by an explicit jump).
1454     // This also means that next_path_num can be called along exception paths.
1455     block2->_pred_count++;
1456     if (i >= ns) {
1457       block2->_is_handler = true;
1458     }
1459 
1460     #ifdef ASSERT
1461     // A block's successors must be distinguishable by BCI.
1462     // That is, no bytecode is allowed to branch to two different
1463     // clones of the same code location.
1464     for (int j = 0; j < i; j++) {
1465       Block* block1 = _successors[j];
1466       if (block1 == block2)  continue;  // duplicates are OK
1467       assert(block1->start() != block2->start(), "successors have unique bcis");
1468     }
1469     #endif
1470   }
1471 }
1472 
1473 //---------------------------successor_for_bci---------------------------------
1474 Parse::Block* Parse::Block::successor_for_bci(int bci) {
1475   for (int i = 0; i < all_successors(); i++) {
1476     Block* block2 = successor_at(i);
1477     if (block2->start() == bci)  return block2;
1478   }
1479   // We can actually reach here if ciTypeFlow traps out a block
1480   // due to an unloaded class, and concurrently with compilation the
1481   // class is then loaded, so that a later phase of the parser is
1482   // able to see more of the bytecode CFG.  Or, the flow pass and
1483   // the parser can have a minor difference of opinion about executability
1484   // of bytecodes.  For example, "obj.field = null" is executable even
1485   // if the field's type is an unloaded class; the flow pass used to
1486   // make a trap for such code.
1487   return nullptr;
1488 }
1489 
1490 
1491 //-----------------------------stack_type_at-----------------------------------
1492 const Type* Parse::Block::stack_type_at(int i) const {
1493   return get_type(flow()->stack_type_at(i));
1494 }
1495 
1496 
1497 //-----------------------------local_type_at-----------------------------------
1498 const Type* Parse::Block::local_type_at(int i) const {
1499   // Make dead locals fall to bottom.
1500   if (_live_locals.size() == 0) {
1501     MethodLivenessResult live_locals = flow()->outer()->method()->liveness_at_bci(start());
1502     // This bitmap can be zero length if we saw a breakpoint.
1503     // In such cases, pretend they are all live.
1504     ((Block*)this)->_live_locals = live_locals;
1505   }
1506   if (_live_locals.size() > 0 && !_live_locals.at(i))
1507     return Type::BOTTOM;
1508 
1509   return get_type(flow()->local_type_at(i));
1510 }
1511 
1512 
1513 #ifndef PRODUCT
1514 
1515 //----------------------------name_for_bc--------------------------------------
1516 // helper method for BytecodeParseHistogram
1517 static const char* name_for_bc(int i) {
1518   return Bytecodes::is_defined(i) ? Bytecodes::name(Bytecodes::cast(i)) : "xxxunusedxxx";
1519 }
1520 
1521 //----------------------------BytecodeParseHistogram------------------------------------
1522 Parse::BytecodeParseHistogram::BytecodeParseHistogram(Parse *p, Compile *c) {
1523   _parser   = p;
1524   _compiler = c;
1525   if( ! _initialized ) { _initialized = true; reset(); }
1526 }
1527 
1528 //----------------------------current_count------------------------------------
1529 int Parse::BytecodeParseHistogram::current_count(BPHType bph_type) {
1530   switch( bph_type ) {
1531   case BPH_transforms: { return _parser->gvn().made_progress(); }
1532   case BPH_values:     { return _parser->gvn().made_new_values(); }
1533   default: { ShouldNotReachHere(); return 0; }
1534   }
1535 }
1536 
1537 //----------------------------initialized--------------------------------------
1538 bool Parse::BytecodeParseHistogram::initialized() { return _initialized; }
1539 
1540 //----------------------------reset--------------------------------------------
1541 void Parse::BytecodeParseHistogram::reset() {
1542   int i = Bytecodes::number_of_codes;
1543   while (i-- > 0) { _bytecodes_parsed[i] = 0; _nodes_constructed[i] = 0; _nodes_transformed[i] = 0; _new_values[i] = 0; }
1544 }
1545 
1546 //----------------------------set_initial_state--------------------------------
1547 // Record info when starting to parse one bytecode
1548 void Parse::BytecodeParseHistogram::set_initial_state( Bytecodes::Code bc ) {
1549   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1550     _initial_bytecode    = bc;
1551     _initial_node_count  = _compiler->unique();
1552     _initial_transforms  = current_count(BPH_transforms);
1553     _initial_values      = current_count(BPH_values);
1554   }
1555 }
1556 
1557 //----------------------------record_change--------------------------------
1558 // Record results of parsing one bytecode
1559 void Parse::BytecodeParseHistogram::record_change() {
1560   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1561     ++_bytecodes_parsed[_initial_bytecode];
1562     _nodes_constructed [_initial_bytecode] += (_compiler->unique() - _initial_node_count);
1563     _nodes_transformed [_initial_bytecode] += (current_count(BPH_transforms) - _initial_transforms);
1564     _new_values        [_initial_bytecode] += (current_count(BPH_values)     - _initial_values);
1565   }
1566 }
1567 
1568 
1569 //----------------------------print--------------------------------------------
1570 void Parse::BytecodeParseHistogram::print(float cutoff) {
1571   ResourceMark rm;
1572   // print profile
1573   int total  = 0;
1574   int i      = 0;
1575   for( i = 0; i < Bytecodes::number_of_codes; ++i ) { total += _bytecodes_parsed[i]; }
1576   int abs_sum = 0;
1577   tty->cr();   //0123456789012345678901234567890123456789012345678901234567890123456789
1578   tty->print_cr("Histogram of %d parsed bytecodes:", total);
1579   if( total == 0 ) { return; }
1580   tty->cr();
1581   tty->print_cr("absolute:  count of compiled bytecodes of this type");
1582   tty->print_cr("relative:  percentage contribution to compiled nodes");
1583   tty->print_cr("nodes   :  Average number of nodes constructed per bytecode");
1584   tty->print_cr("rnodes  :  Significance towards total nodes constructed, (nodes*relative)");
1585   tty->print_cr("transforms: Average amount of transform progress per bytecode compiled");
1586   tty->print_cr("values  :  Average number of node values improved per bytecode");
1587   tty->print_cr("name    :  Bytecode name");
1588   tty->cr();
1589   tty->print_cr("  absolute  relative   nodes  rnodes  transforms  values   name");
1590   tty->print_cr("----------------------------------------------------------------------");
1591   while (--i > 0) {
1592     int       abs = _bytecodes_parsed[i];
1593     float     rel = abs * 100.0F / total;
1594     float   nodes = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_constructed[i])/_bytecodes_parsed[i];
1595     float  rnodes = _bytecodes_parsed[i] == 0 ? 0 :  rel * nodes;
1596     float  xforms = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_transformed[i])/_bytecodes_parsed[i];
1597     float  values = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _new_values       [i])/_bytecodes_parsed[i];
1598     if (cutoff <= rel) {
1599       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));
1600       abs_sum += abs;
1601     }
1602   }
1603   tty->print_cr("----------------------------------------------------------------------");
1604   float rel_sum = abs_sum * 100.0F / total;
1605   tty->print_cr("%10d  %7.2f%%    (cutoff = %.2f%%)", abs_sum, rel_sum, cutoff);
1606   tty->print_cr("----------------------------------------------------------------------");
1607   tty->cr();
1608 }
1609 #endif
1610 
1611 //----------------------------load_state_from----------------------------------
1612 // Load block/map/sp.  But not do not touch iter/bci.
1613 void Parse::load_state_from(Block* block) {
1614   set_block(block);
1615   // load the block's JVM state:
1616   set_map(block->start_map());
1617   set_sp( block->start_sp());
1618 }
1619 
1620 
1621 //-----------------------------record_state------------------------------------
1622 void Parse::Block::record_state(Parse* p) {
1623   assert(!is_merged(), "can only record state once, on 1st inflow");
1624   assert(start_sp() == p->sp(), "stack pointer must agree with ciTypeFlow");
1625   set_start_map(p->stop());
1626 }
1627 
1628 
1629 //------------------------------do_one_block-----------------------------------
1630 void Parse::do_one_block() {
1631   if (TraceOptoParse) {
1632     Block *b = block();
1633     int ns = b->num_successors();
1634     int nt = b->all_successors();
1635 
1636     tty->print("Parsing block #%d at bci [%d,%d), successors:",
1637                   block()->rpo(), block()->start(), block()->limit());
1638     for (int i = 0; i < nt; i++) {
1639       tty->print((( i < ns) ? " %d" : " %d(exception block)"), b->successor_at(i)->rpo());
1640     }
1641     if (b->is_loop_head()) {
1642       tty->print("  loop head");
1643     }
1644     if (b->is_irreducible_loop_entry()) {
1645       tty->print("  irreducible");
1646     }
1647     tty->cr();
1648   }
1649 
1650   assert(block()->is_merged(), "must be merged before being parsed");
1651   block()->mark_parsed();
1652 
1653   // Set iterator to start of block.
1654   iter().reset_to_bci(block()->start());
1655 
1656   if (ProfileExceptionHandlers && block()->is_handler()) {
1657     ciMethodData* methodData = method()->method_data();
1658     if (methodData->is_mature()) {
1659       ciBitData data = methodData->exception_handler_bci_to_data(block()->start());
1660       if (!data.exception_handler_entered() || StressPrunedExceptionHandlers) {
1661         // dead catch block
1662         // Emit an uncommon trap instead of processing the block.
1663         set_parse_bci(block()->start());
1664         uncommon_trap(Deoptimization::Reason_unreached,
1665                       Deoptimization::Action_reinterpret,
1666                       nullptr, "dead catch block");
1667         return;
1668       }
1669     }
1670   }
1671 
1672   CompileLog* log = C->log();
1673 
1674   // Parse bytecodes
1675   while (!stopped() && !failing()) {
1676     iter().next();
1677 
1678     // Learn the current bci from the iterator:
1679     set_parse_bci(iter().cur_bci());
1680 
1681     if (bci() == block()->limit()) {
1682       // Do not walk into the next block until directed by do_all_blocks.
1683       merge(bci());
1684       break;
1685     }
1686     assert(bci() < block()->limit(), "bci still in block");
1687 
1688     if (log != nullptr) {
1689       // Output an optional context marker, to help place actions
1690       // that occur during parsing of this BC.  If there is no log
1691       // output until the next context string, this context string
1692       // will be silently ignored.
1693       log->set_context("bc code='%d' bci='%d'", (int)bc(), bci());
1694     }
1695 
1696     if (block()->has_trap_at(bci())) {
1697       // We must respect the flow pass's traps, because it will refuse
1698       // to produce successors for trapping blocks.
1699       int trap_index = block()->flow()->trap_index();
1700       assert(trap_index != 0, "trap index must be valid");
1701       uncommon_trap(trap_index);
1702       break;
1703     }
1704 
1705     NOT_PRODUCT( parse_histogram()->set_initial_state(bc()); );
1706 
1707 #ifdef ASSERT
1708     int pre_bc_sp = sp();
1709     int inputs, depth;
1710     bool have_se = !stopped() && compute_stack_effects(inputs, depth);
1711     assert(!have_se || pre_bc_sp >= inputs, "have enough stack to execute this BC: pre_bc_sp=%d, inputs=%d", pre_bc_sp, inputs);
1712 #endif //ASSERT
1713 
1714     do_one_bytecode();
1715     if (failing()) return;
1716 
1717     assert(!have_se || stopped() || failing() || (sp() - pre_bc_sp) == depth,
1718            "incorrect depth prediction: sp=%d, pre_bc_sp=%d, depth=%d", sp(), pre_bc_sp, depth);
1719 
1720     do_exceptions();
1721 
1722     NOT_PRODUCT( parse_histogram()->record_change(); );
1723 
1724     if (log != nullptr)
1725       log->clear_context();  // skip marker if nothing was printed
1726 
1727     // Fall into next bytecode.  Each bytecode normally has 1 sequential
1728     // successor which is typically made ready by visiting this bytecode.
1729     // If the successor has several predecessors, then it is a merge
1730     // point, starts a new basic block, and is handled like other basic blocks.
1731   }
1732 }
1733 
1734 
1735 //------------------------------merge------------------------------------------
1736 void Parse::set_parse_bci(int bci) {
1737   set_bci(bci);
1738   Node_Notes* nn = C->default_node_notes();
1739   if (nn == nullptr)  return;
1740 
1741   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
1742   if (!DebugInlinedCalls && depth() > 1) {
1743     return;
1744   }
1745 
1746   // Update the JVMS annotation, if present.
1747   JVMState* jvms = nn->jvms();
1748   if (jvms != nullptr && jvms->bci() != bci) {
1749     // Update the JVMS.
1750     jvms = jvms->clone_shallow(C);
1751     jvms->set_bci(bci);
1752     nn->set_jvms(jvms);
1753   }
1754 }
1755 
1756 //------------------------------merge------------------------------------------
1757 // Merge the current mapping into the basic block starting at bci
1758 void Parse::merge(int target_bci) {
1759   Block* target = successor_for_bci(target_bci);
1760   if (target == nullptr) { handle_missing_successor(target_bci); return; }
1761   assert(!target->is_ready(), "our arrival must be expected");
1762   int pnum = target->next_path_num();
1763   merge_common(target, pnum);
1764 }
1765 
1766 //-------------------------merge_new_path--------------------------------------
1767 // Merge the current mapping into the basic block, using a new path
1768 void Parse::merge_new_path(int target_bci) {
1769   Block* target = successor_for_bci(target_bci);
1770   if (target == nullptr) { handle_missing_successor(target_bci); return; }
1771   assert(!target->is_ready(), "new path into frozen graph");
1772   int pnum = target->add_new_path();
1773   merge_common(target, pnum);
1774 }
1775 
1776 //-------------------------merge_exception-------------------------------------
1777 // Merge the current mapping into the basic block starting at bci
1778 // The ex_oop must be pushed on the stack, unlike throw_to_exit.
1779 void Parse::merge_exception(int target_bci) {
1780 #ifdef ASSERT
1781   if (target_bci <= bci()) {
1782     C->set_exception_backedge();
1783   }
1784 #endif
1785   assert(sp() == 1, "must have only the throw exception on the stack");
1786   Block* target = successor_for_bci(target_bci);
1787   if (target == nullptr) { handle_missing_successor(target_bci); return; }
1788   assert(target->is_handler(), "exceptions are handled by special blocks");
1789   int pnum = target->add_new_path();
1790   merge_common(target, pnum);
1791 }
1792 
1793 //--------------------handle_missing_successor---------------------------------
1794 void Parse::handle_missing_successor(int target_bci) {
1795 #ifndef PRODUCT
1796   Block* b = block();
1797   int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1;
1798   tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci);
1799 #endif
1800   ShouldNotReachHere();
1801 }
1802 
1803 //--------------------------merge_common---------------------------------------
1804 void Parse::merge_common(Parse::Block* target, int pnum) {
1805   if (TraceOptoParse) {
1806     tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start());
1807   }
1808 
1809   // Zap extra stack slots to top
1810   assert(sp() == target->start_sp(), "");
1811   clean_stack(sp());
1812 
1813   // Check for merge conflicts involving inline types
1814   JVMState* old_jvms = map()->jvms();
1815   int old_bci = bci();
1816   JVMState* tmp_jvms = old_jvms->clone_shallow(C);
1817   tmp_jvms->set_should_reexecute(true);
1818   tmp_jvms->bind_map(map());
1819   // Execution needs to restart a the next bytecode (entry of next
1820   // block)
1821   if (target->is_merged() ||
1822       pnum > PhiNode::Input ||
1823       target->is_handler() ||
1824       target->is_loop_head()) {
1825     set_parse_bci(target->start());
1826     for (uint j = TypeFunc::Parms; j < map()->req(); j++) {
1827       Node* n = map()->in(j);                 // Incoming change to target state.
1828       const Type* t = nullptr;
1829       if (tmp_jvms->is_loc(j)) {
1830         t = target->local_type_at(j - tmp_jvms->locoff());
1831       } else if (tmp_jvms->is_stk(j) && j < (uint)sp() + tmp_jvms->stkoff()) {
1832         t = target->stack_type_at(j - tmp_jvms->stkoff());
1833       }
1834       if (t != nullptr && t != Type::BOTTOM) {
1835         // An object can appear in the JVMS as either an oop or an InlineTypeNode. If the merge is
1836         // an InlineTypeNode, we need all the merge inputs to be InlineTypeNodes. Else, if the
1837         // merge is an oop, each merge input needs to be either an oop or an buffered
1838         // InlineTypeNode.
1839         if (!t->is_inlinetypeptr()) {
1840           // The merge cannot be an InlineTypeNode, ensure the input is buffered if it is an
1841           // InlineTypeNode
1842           if (n->is_InlineType()) {
1843             map()->set_req(j, n->as_InlineType()->buffer(this));
1844           }
1845         } else {
1846           // Since the merge is a value object, it can either be an oop or an InlineTypeNode
1847           if (!target->is_merged()) {
1848             // This is the first processed input of the merge. If it is an InlineTypeNode, the
1849             // merge will be an InlineTypeNode. Else, try to scalarize so the merge can be
1850             // scalarized as well. However, we cannot blindly scalarize an inline type oop here
1851             // since it may be larval
1852             if (!n->is_InlineType() && gvn().type(n)->is_zero_type()) {
1853               // Null constant implies that this is not a larval object
1854               map()->set_req(j, InlineTypeNode::make_null(gvn(), t->inline_klass()));
1855             }
1856           } else {
1857             Node* phi = target->start_map()->in(j);
1858             if (phi->is_InlineType()) {
1859               // Larval oops cannot be merged with non-larval ones, and since the merge point is
1860               // non-larval, n must be non-larval as well. As a result, we can scalarize n to merge
1861               // into phi
1862               if (!n->is_InlineType()) {
1863                 map()->set_req(j, InlineTypeNode::make_from_oop(this, n, t->inline_klass()));
1864               }
1865             } else {
1866               // The merge is an oop phi, ensure the input is buffered if it is an InlineTypeNode
1867               if (n->is_InlineType()) {
1868                 map()->set_req(j, n->as_InlineType()->buffer(this));
1869               }
1870             }
1871           }
1872         }
1873       }
1874     }
1875   }
1876   old_jvms->bind_map(map());
1877   set_parse_bci(old_bci);
1878 
1879   if (!target->is_merged()) {   // No prior mapping at this bci
1880     if (TraceOptoParse) { tty->print(" with empty state");  }
1881 
1882     // If this path is dead, do not bother capturing it as a merge.
1883     // It is "as if" we had 1 fewer predecessors from the beginning.
1884     if (stopped()) {
1885       if (TraceOptoParse)  tty->print_cr(", but path is dead and doesn't count");
1886       return;
1887     }
1888 
1889     // Make a region if we know there are multiple or unpredictable inputs.
1890     // (Also, if this is a plain fall-through, we might see another region,
1891     // which must not be allowed into this block's map.)
1892     if (pnum > PhiNode::Input         // Known multiple inputs.
1893         || target->is_handler()       // These have unpredictable inputs.
1894         || target->is_loop_head()     // Known multiple inputs
1895         || control()->is_Region()) {  // We must hide this guy.
1896 
1897       int current_bci = bci();
1898       set_parse_bci(target->start()); // Set target bci
1899       if (target->is_SEL_head()) {
1900         DEBUG_ONLY( target->mark_merged_backedge(block()); )
1901         if (target->start() == 0) {
1902           // Add Parse Predicates for the special case when
1903           // there are backbranches to the method entry.
1904           add_parse_predicates();
1905         }
1906       }
1907       // Add a Region to start the new basic block.  Phis will be added
1908       // later lazily.
1909       int edges = target->pred_count();
1910       if (edges < pnum)  edges = pnum;  // might be a new path!
1911       RegionNode *r = new RegionNode(edges+1);
1912       gvn().set_type(r, Type::CONTROL);
1913       record_for_igvn(r);
1914       // zap all inputs to null for debugging (done in Node(uint) constructor)
1915       // for (int j = 1; j < edges+1; j++) { r->init_req(j, nullptr); }
1916       r->init_req(pnum, control());
1917       set_control(r);
1918       target->copy_irreducible_status_to(r, jvms());
1919       set_parse_bci(current_bci); // Restore bci
1920     }
1921 
1922     // Convert the existing Parser mapping into a mapping at this bci.
1923     store_state_to(target);
1924     assert(target->is_merged(), "do not come here twice");
1925 
1926   } else {                      // Prior mapping at this bci
1927     if (TraceOptoParse) {  tty->print(" with previous state"); }
1928 #ifdef ASSERT
1929     if (target->is_SEL_head()) {
1930       target->mark_merged_backedge(block());
1931     }
1932 #endif
1933 
1934     // We must not manufacture more phis if the target is already parsed.
1935     bool nophi = target->is_parsed();
1936 
1937     SafePointNode* newin = map();// Hang on to incoming mapping
1938     Block* save_block = block(); // Hang on to incoming block;
1939     load_state_from(target);    // Get prior mapping
1940 
1941     assert(newin->jvms()->locoff() == jvms()->locoff(), "JVMS layouts agree");
1942     assert(newin->jvms()->stkoff() == jvms()->stkoff(), "JVMS layouts agree");
1943     assert(newin->jvms()->monoff() == jvms()->monoff(), "JVMS layouts agree");
1944     assert(newin->jvms()->endoff() == jvms()->endoff(), "JVMS layouts agree");
1945 
1946     // Iterate over my current mapping and the old mapping.
1947     // Where different, insert Phi functions.
1948     // Use any existing Phi functions.
1949     assert(control()->is_Region(), "must be merging to a region");
1950     RegionNode* r = control()->as_Region();
1951 
1952     // Compute where to merge into
1953     // Merge incoming control path
1954     r->init_req(pnum, newin->control());
1955 
1956     if (pnum == 1) {            // Last merge for this Region?
1957       if (!block()->flow()->is_irreducible_loop_secondary_entry()) {
1958         Node* result = _gvn.transform(r);
1959         if (r != result && TraceOptoParse) {
1960           tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx);
1961         }
1962       }
1963       record_for_igvn(r);
1964     }
1965 
1966     // Update all the non-control inputs to map:
1967     assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms");
1968     bool check_elide_phi = target->is_SEL_backedge(save_block);
1969     bool last_merge = (pnum == PhiNode::Input);
1970     for (uint j = 1; j < newin->req(); j++) {
1971       Node* m = map()->in(j);   // Current state of target.
1972       Node* n = newin->in(j);   // Incoming change to target state.
1973       Node* phi;
1974       if (m->is_Phi() && m->as_Phi()->region() == r) {
1975         phi = m;
1976       } else if (m->is_InlineType() && m->as_InlineType()->has_phi_inputs(r)) {
1977         phi = m;
1978       } else {
1979         phi = nullptr;
1980       }
1981       if (m != n) {             // Different; must merge
1982         switch (j) {
1983         // Frame pointer and Return Address never changes
1984         case TypeFunc::FramePtr:// Drop m, use the original value
1985         case TypeFunc::ReturnAdr:
1986           break;
1987         case TypeFunc::Memory:  // Merge inputs to the MergeMem node
1988           assert(phi == nullptr, "the merge contains phis, not vice versa");
1989           merge_memory_edges(n->as_MergeMem(), pnum, nophi);
1990           continue;
1991         default:                // All normal stuff
1992           if (phi == nullptr) {
1993             const JVMState* jvms = map()->jvms();
1994             if (EliminateNestedLocks &&
1995                 jvms->is_mon(j) && jvms->is_monitor_box(j)) {
1996               // BoxLock nodes are not commoning when EliminateNestedLocks is on.
1997               // Use old BoxLock node as merged box.
1998               assert(newin->jvms()->is_monitor_box(j), "sanity");
1999               // This assert also tests that nodes are BoxLock.
2000               assert(BoxLockNode::same_slot(n, m), "sanity");
2001               BoxLockNode* old_box = m->as_BoxLock();
2002               if (n->as_BoxLock()->is_unbalanced() && !old_box->is_unbalanced()) {
2003                 // Preserve Unbalanced status.
2004                 //
2005                 // `old_box` can have only Regular or Coarsened status
2006                 // because this code is executed only during Parse phase and
2007                 // Incremental Inlining before EA and Macro nodes elimination.
2008                 //
2009                 // Incremental Inlining is executed after IGVN optimizations
2010                 // during which BoxLock can be marked as Coarsened.
2011                 old_box->set_coarsened(); // Verifies state
2012                 old_box->set_unbalanced();
2013               }
2014               C->gvn_replace_by(n, m);
2015             } else if (!check_elide_phi || !target->can_elide_SEL_phi(j)) {
2016               phi = ensure_phi(j, nophi);
2017             }
2018           }
2019           break;
2020         }
2021       }
2022       // At this point, n might be top if:
2023       //  - there is no phi (because TypeFlow detected a conflict), or
2024       //  - the corresponding control edges is top (a dead incoming path)
2025       // It is a bug if we create a phi which sees a garbage value on a live path.
2026 
2027       // Merging two inline types?
2028       if (phi != nullptr && phi->is_InlineType()) {
2029         // Reload current state because it may have been updated by ensure_phi
2030         assert(phi == map()->in(j), "unexpected value in map");
2031         assert(phi->as_InlineType()->has_phi_inputs(r), "");
2032         InlineTypeNode* vtm = phi->as_InlineType(); // Current inline type
2033         InlineTypeNode* vtn = n->as_InlineType(); // Incoming inline type
2034         assert(vtm == phi, "Inline type should have Phi input");
2035 
2036 #ifdef ASSERT
2037         if (TraceOptoParse) {
2038           tty->print_cr("\nMerging inline types");
2039           tty->print_cr("Current:");
2040           vtm->dump(2);
2041           tty->print_cr("Incoming:");
2042           vtn->dump(2);
2043           tty->cr();
2044         }
2045 #endif
2046         // Do the merge
2047         vtm->merge_with(&_gvn, vtn, pnum, last_merge);
2048         if (last_merge) {
2049           map()->set_req(j, _gvn.transform(vtm));
2050           record_for_igvn(vtm);
2051         }
2052       } else if (phi != nullptr) {
2053         assert(n != top() || r->in(pnum) == top(), "live value must not be garbage");
2054         assert(phi->as_Phi()->region() == r, "");
2055         phi->set_req(pnum, n);  // Then add 'n' to the merge
2056         if (last_merge) {
2057           // Last merge for this Phi.
2058           // So far, Phis have had a reasonable type from ciTypeFlow.
2059           // Now _gvn will join that with the meet of current inputs.
2060           // BOTTOM is never permissible here, 'cause pessimistically
2061           // Phis of pointers cannot lose the basic pointer type.
2062           DEBUG_ONLY(const Type* bt1 = phi->bottom_type());
2063           assert(bt1 != Type::BOTTOM, "should not be building conflict phis");
2064           map()->set_req(j, _gvn.transform(phi));
2065           DEBUG_ONLY(const Type* bt2 = phi->bottom_type());
2066           assert(bt2->higher_equal_speculative(bt1), "must be consistent with type-flow");
2067           record_for_igvn(phi);
2068         }
2069       }
2070     } // End of for all values to be merged
2071 
2072     if (last_merge && !r->in(0)) {         // The occasional useless Region
2073       assert(control() == r, "");
2074       set_control(r->nonnull_req());
2075     }
2076 
2077     map()->merge_replaced_nodes_with(newin);
2078 
2079     // newin has been subsumed into the lazy merge, and is now dead.
2080     set_block(save_block);
2081 
2082     stop();                     // done with this guy, for now
2083   }
2084 
2085   if (TraceOptoParse) {
2086     tty->print_cr(" on path %d", pnum);
2087   }
2088 
2089   // Done with this parser state.
2090   assert(stopped(), "");
2091 }
2092 
2093 
2094 //--------------------------merge_memory_edges---------------------------------
2095 void Parse::merge_memory_edges(MergeMemNode* n, int pnum, bool nophi) {
2096   // (nophi means we must not create phis, because we already parsed here)
2097   assert(n != nullptr, "");
2098   // Merge the inputs to the MergeMems
2099   MergeMemNode* m = merged_memory();
2100 
2101   assert(control()->is_Region(), "must be merging to a region");
2102   RegionNode* r = control()->as_Region();
2103 
2104   PhiNode* base = nullptr;
2105   MergeMemNode* remerge = nullptr;
2106   for (MergeMemStream mms(m, n); mms.next_non_empty2(); ) {
2107     Node *p = mms.force_memory();
2108     Node *q = mms.memory2();
2109     if (mms.is_empty() && nophi) {
2110       // Trouble:  No new splits allowed after a loop body is parsed.
2111       // Instead, wire the new split into a MergeMem on the backedge.
2112       // The optimizer will sort it out, slicing the phi.
2113       if (remerge == nullptr) {
2114         guarantee(base != nullptr, "");
2115         assert(base->in(0) != nullptr, "should not be xformed away");
2116         remerge = MergeMemNode::make(base->in(pnum));
2117         gvn().set_type(remerge, Type::MEMORY);
2118         base->set_req(pnum, remerge);
2119       }
2120       remerge->set_memory_at(mms.alias_idx(), q);
2121       continue;
2122     }
2123     assert(!q->is_MergeMem(), "");
2124     PhiNode* phi;
2125     if (p != q) {
2126       phi = ensure_memory_phi(mms.alias_idx(), nophi);
2127     } else {
2128       if (p->is_Phi() && p->as_Phi()->region() == r)
2129         phi = p->as_Phi();
2130       else
2131         phi = nullptr;
2132     }
2133     // Insert q into local phi
2134     if (phi != nullptr) {
2135       assert(phi->region() == r, "");
2136       p = phi;
2137       phi->set_req(pnum, q);
2138       if (mms.at_base_memory()) {
2139         base = phi;  // delay transforming it
2140       } else if (pnum == 1) {
2141         record_for_igvn(phi);
2142         p = _gvn.transform(phi);
2143       }
2144       mms.set_memory(p);// store back through the iterator
2145     }
2146   }
2147   // Transform base last, in case we must fiddle with remerging.
2148   if (base != nullptr && pnum == 1) {
2149     record_for_igvn(base);
2150     m->set_base_memory(_gvn.transform(base));
2151   }
2152 }
2153 
2154 
2155 //------------------------ensure_phis_everywhere-------------------------------
2156 void Parse::ensure_phis_everywhere() {
2157   ensure_phi(TypeFunc::I_O);
2158 
2159   // Ensure a phi on all currently known memories.
2160   for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
2161     ensure_memory_phi(mms.alias_idx());
2162     DEBUG_ONLY(mms.set_memory());  // keep the iterator happy
2163   }
2164 
2165   // Note:  This is our only chance to create phis for memory slices.
2166   // If we miss a slice that crops up later, it will have to be
2167   // merged into the base-memory phi that we are building here.
2168   // Later, the optimizer will comb out the knot, and build separate
2169   // phi-loops for each memory slice that matters.
2170 
2171   // Monitors must nest nicely and not get confused amongst themselves.
2172   // Phi-ify everything up to the monitors, though.
2173   uint monoff = map()->jvms()->monoff();
2174   uint nof_monitors = map()->jvms()->nof_monitors();
2175 
2176   assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms");
2177   bool check_elide_phi = block()->is_SEL_head();
2178   for (uint i = TypeFunc::Parms; i < monoff; i++) {
2179     if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) {
2180       ensure_phi(i);
2181     }
2182   }
2183 
2184   // Even monitors need Phis, though they are well-structured.
2185   // This is true for OSR methods, and also for the rare cases where
2186   // a monitor object is the subject of a replace_in_map operation.
2187   // See bugs 4426707 and 5043395.
2188   for (uint m = 0; m < nof_monitors; m++) {
2189     ensure_phi(map()->jvms()->monitor_obj_offset(m));
2190   }
2191 }
2192 
2193 
2194 //-----------------------------add_new_path------------------------------------
2195 // Add a previously unaccounted predecessor to this block.
2196 int Parse::Block::add_new_path() {
2197   // If there is no map, return the lowest unused path number.
2198   if (!is_merged())  return pred_count()+1;  // there will be a map shortly
2199 
2200   SafePointNode* map = start_map();
2201   if (!map->control()->is_Region())
2202     return pred_count()+1;  // there may be a region some day
2203   RegionNode* r = map->control()->as_Region();
2204 
2205   // Add new path to the region.
2206   uint pnum = r->req();
2207   r->add_req(nullptr);
2208 
2209   for (uint i = 1; i < map->req(); i++) {
2210     Node* n = map->in(i);
2211     if (i == TypeFunc::Memory) {
2212       // Ensure a phi on all currently known memories.
2213       for (MergeMemStream mms(n->as_MergeMem()); mms.next_non_empty(); ) {
2214         Node* phi = mms.memory();
2215         if (phi->is_Phi() && phi->as_Phi()->region() == r) {
2216           assert(phi->req() == pnum, "must be same size as region");
2217           phi->add_req(nullptr);
2218         }
2219       }
2220     } else {
2221       if (n->is_Phi() && n->as_Phi()->region() == r) {
2222         assert(n->req() == pnum, "must be same size as region");
2223         n->add_req(nullptr);
2224       } else if (n->is_InlineType() && n->as_InlineType()->has_phi_inputs(r)) {
2225         n->as_InlineType()->add_new_path(r);
2226       }
2227     }
2228   }
2229 
2230   return pnum;
2231 }
2232 
2233 //------------------------------ensure_phi-------------------------------------
2234 // Turn the idx'th entry of the current map into a Phi
2235 Node* Parse::ensure_phi(int idx, bool nocreate) {
2236   SafePointNode* map = this->map();
2237   Node* region = map->control();
2238   assert(region->is_Region(), "");
2239 
2240   Node* o = map->in(idx);
2241   assert(o != nullptr, "");
2242 
2243   if (o == top())  return nullptr; // TOP always merges into TOP
2244 
2245   if (o->is_Phi() && o->as_Phi()->region() == region) {
2246     return o->as_Phi();
2247   }
2248   InlineTypeNode* vt = o->isa_InlineType();
2249   if (vt != nullptr && vt->has_phi_inputs(region)) {
2250     return vt;
2251   }
2252 
2253   // Now use a Phi here for merging
2254   assert(!nocreate, "Cannot build a phi for a block already parsed.");
2255   const JVMState* jvms = map->jvms();
2256   const Type* t = nullptr;
2257   if (jvms->is_loc(idx)) {
2258     t = block()->local_type_at(idx - jvms->locoff());
2259   } else if (jvms->is_stk(idx)) {
2260     t = block()->stack_type_at(idx - jvms->stkoff());
2261   } else if (jvms->is_mon(idx)) {
2262     assert(!jvms->is_monitor_box(idx), "no phis for boxes");
2263     t = TypeInstPtr::BOTTOM; // this is sufficient for a lock object
2264   } else if ((uint)idx < TypeFunc::Parms) {
2265     t = o->bottom_type();  // Type::RETURN_ADDRESS or such-like.
2266   } else {
2267     assert(false, "no type information for this phi");
2268   }
2269 
2270   // If the type falls to bottom, then this must be a local that
2271   // is already dead or is mixing ints and oops or some such.
2272   // Forcing it to top makes it go dead.
2273   if (t == Type::BOTTOM) {
2274     map->set_req(idx, top());
2275     return nullptr;
2276   }
2277 
2278   // Do not create phis for top either.
2279   // A top on a non-null control flow must be an unused even after the.phi.
2280   if (t == Type::TOP || t == Type::HALF) {
2281     map->set_req(idx, top());
2282     return nullptr;
2283   }
2284 
2285   if (vt != nullptr && t->is_inlinetypeptr()) {
2286     // Inline types are merged by merging their field values.
2287     // Create a cloned InlineTypeNode with phi inputs that
2288     // represents the merged inline type and update the map.
2289     vt = vt->clone_with_phis(&_gvn, region);
2290     map->set_req(idx, vt);
2291     return vt;
2292   } else {
2293     PhiNode* phi = PhiNode::make(region, o, t);
2294     gvn().set_type(phi, t);
2295     if (C->do_escape_analysis()) record_for_igvn(phi);
2296     map->set_req(idx, phi);
2297     return phi;
2298   }
2299 }
2300 
2301 //--------------------------ensure_memory_phi----------------------------------
2302 // Turn the idx'th slice of the current memory into a Phi
2303 PhiNode *Parse::ensure_memory_phi(int idx, bool nocreate) {
2304   MergeMemNode* mem = merged_memory();
2305   Node* region = control();
2306   assert(region->is_Region(), "");
2307 
2308   Node *o = (idx == Compile::AliasIdxBot)? mem->base_memory(): mem->memory_at(idx);
2309   assert(o != nullptr && o != top(), "");
2310 
2311   PhiNode* phi;
2312   if (o->is_Phi() && o->as_Phi()->region() == region) {
2313     phi = o->as_Phi();
2314     if (phi == mem->base_memory() && idx >= Compile::AliasIdxRaw) {
2315       // clone the shared base memory phi to make a new memory split
2316       assert(!nocreate, "Cannot build a phi for a block already parsed.");
2317       const Type* t = phi->bottom_type();
2318       const TypePtr* adr_type = C->get_adr_type(idx);
2319       phi = phi->slice_memory(adr_type);
2320       gvn().set_type(phi, t);
2321     }
2322     return phi;
2323   }
2324 
2325   // Now use a Phi here for merging
2326   assert(!nocreate, "Cannot build a phi for a block already parsed.");
2327   const Type* t = o->bottom_type();
2328   const TypePtr* adr_type = C->get_adr_type(idx);
2329   phi = PhiNode::make(region, o, t, adr_type);
2330   gvn().set_type(phi, t);
2331   if (idx == Compile::AliasIdxBot)
2332     mem->set_base_memory(phi);
2333   else
2334     mem->set_memory_at(idx, phi);
2335   return phi;
2336 }
2337 
2338 //------------------------------call_register_finalizer-----------------------
2339 // Check the klass of the receiver and call register_finalizer if the
2340 // class need finalization.
2341 void Parse::call_register_finalizer() {
2342   Node* receiver = local(0);
2343   assert(receiver != nullptr && receiver->bottom_type()->isa_instptr() != nullptr,
2344          "must have non-null instance type");
2345 
2346   const TypeInstPtr *tinst = receiver->bottom_type()->isa_instptr();
2347   if (tinst != nullptr && tinst->is_loaded() && !tinst->klass_is_exact()) {
2348     // The type isn't known exactly so see if CHA tells us anything.
2349     ciInstanceKlass* ik = tinst->instance_klass();
2350     if (!Dependencies::has_finalizable_subclass(ik)) {
2351       // No finalizable subclasses so skip the dynamic check.
2352       C->dependencies()->assert_has_no_finalizable_subclasses(ik);
2353       return;
2354     }
2355   }
2356 
2357   // Insert a dynamic test for whether the instance needs
2358   // finalization.  In general this will fold up since the concrete
2359   // class is often visible so the access flags are constant.
2360   Node* klass_addr = basic_plus_adr( receiver, receiver, oopDesc::klass_offset_in_bytes() );
2361   Node* klass = _gvn.transform(LoadKlassNode::make(_gvn, immutable_memory(), klass_addr, TypeInstPtr::KLASS));
2362 
2363   Node* access_flags_addr = basic_plus_adr(klass, klass, in_bytes(Klass::misc_flags_offset()));
2364   Node* access_flags = make_load(nullptr, access_flags_addr, TypeInt::UBYTE, T_BOOLEAN, MemNode::unordered);
2365 
2366   Node* mask  = _gvn.transform(new AndINode(access_flags, intcon(KlassFlags::_misc_has_finalizer)));
2367   Node* check = _gvn.transform(new CmpINode(mask, intcon(0)));
2368   Node* test  = _gvn.transform(new BoolNode(check, BoolTest::ne));
2369 
2370   IfNode* iff = create_and_map_if(control(), test, PROB_MAX, COUNT_UNKNOWN);
2371 
2372   RegionNode* result_rgn = new RegionNode(3);
2373   record_for_igvn(result_rgn);
2374 
2375   Node *skip_register = _gvn.transform(new IfFalseNode(iff));
2376   result_rgn->init_req(1, skip_register);
2377 
2378   Node *needs_register = _gvn.transform(new IfTrueNode(iff));
2379   set_control(needs_register);
2380   if (stopped()) {
2381     // There is no slow path.
2382     result_rgn->init_req(2, top());
2383   } else {
2384     Node *call = make_runtime_call(RC_NO_LEAF,
2385                                    OptoRuntime::register_finalizer_Type(),
2386                                    OptoRuntime::register_finalizer_Java(),
2387                                    nullptr, TypePtr::BOTTOM,
2388                                    receiver);
2389     make_slow_call_ex(call, env()->Throwable_klass(), true);
2390 
2391     Node* fast_io  = call->in(TypeFunc::I_O);
2392     Node* fast_mem = call->in(TypeFunc::Memory);
2393     // These two phis are pre-filled with copies of of the fast IO and Memory
2394     Node* io_phi   = PhiNode::make(result_rgn, fast_io,  Type::ABIO);
2395     Node* mem_phi  = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);
2396 
2397     result_rgn->init_req(2, control());
2398     io_phi    ->init_req(2, i_o());
2399     mem_phi   ->init_req(2, reset_memory());
2400 
2401     set_all_memory( _gvn.transform(mem_phi) );
2402     set_i_o(        _gvn.transform(io_phi) );
2403   }
2404 
2405   set_control( _gvn.transform(result_rgn) );
2406 }
2407 
2408 // Add check to deoptimize once holder klass is fully initialized.
2409 void Parse::clinit_deopt() {
2410   assert(C->has_method(), "only for normal compilations");
2411   assert(depth() == 1, "only for main compiled method");
2412   assert(is_normal_parse(), "no barrier needed on osr entry");
2413   assert(!method()->holder()->is_not_initialized(), "initialization should have been started");
2414 
2415   set_parse_bci(0);
2416 
2417   Node* holder = makecon(TypeKlassPtr::make(method()->holder(), Type::trust_interfaces));
2418   guard_klass_being_initialized(holder);
2419 }
2420 
2421 //------------------------------return_current---------------------------------
2422 // Append current _map to _exit_return
2423 void Parse::return_current(Node* value) {
2424   if (method()->intrinsic_id() == vmIntrinsics::_Object_init) {
2425     call_register_finalizer();
2426   }
2427 
2428   // frame pointer is always same, already captured
2429   if (value != nullptr) {
2430     Node* phi = _exits.argument(0);
2431     const Type* return_type = phi->bottom_type();
2432     const TypeInstPtr* tr = return_type->isa_instptr();
2433     if ((tf()->returns_inline_type_as_fields() || (_caller->has_method() && !Compile::current()->inlining_incrementally())) &&
2434         return_type->is_inlinetypeptr()) {
2435       // Inline type is returned as fields, make sure it is scalarized
2436       if (!value->is_InlineType()) {
2437         value = InlineTypeNode::make_from_oop(this, value, return_type->inline_klass());
2438       }
2439       if (!_caller->has_method() || Compile::current()->inlining_incrementally()) {
2440         // Returning from root or an incrementally inlined method. Make sure all non-flat
2441         // fields are buffered and re-execute if allocation triggers deoptimization.
2442         PreserveReexecuteState preexecs(this);
2443         assert(tf()->returns_inline_type_as_fields(), "must be returned as fields");
2444         jvms()->set_should_reexecute(true);
2445         inc_sp(1);
2446         value = value->as_InlineType()->allocate_fields(this);
2447       }
2448     } else if (value->is_InlineType()) {
2449       // Inline type is returned as oop, make sure it is buffered and re-execute
2450       // if allocation triggers deoptimization.
2451       PreserveReexecuteState preexecs(this);
2452       jvms()->set_should_reexecute(true);
2453       inc_sp(1);
2454       value = value->as_InlineType()->buffer(this);
2455     }
2456     // ...else
2457     // If returning oops to an interface-return, there is a silent free
2458     // cast from oop to interface allowed by the Verifier. Make it explicit here.
2459     phi->add_req(value);
2460   }
2461 
2462   // Do not set_parse_bci, so that return goo is credited to the return insn.
2463   set_bci(InvocationEntryBci);
2464   if (method()->is_synchronized()) {
2465     shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
2466   }
2467   if (C->env()->dtrace_method_probes()) {
2468     make_dtrace_method_exit(method());
2469   }
2470 
2471   SafePointNode* exit_return = _exits.map();
2472   exit_return->in( TypeFunc::Control  )->add_req( control() );
2473   exit_return->in( TypeFunc::I_O      )->add_req( i_o    () );
2474   Node *mem = exit_return->in( TypeFunc::Memory   );
2475   for (MergeMemStream mms(mem->as_MergeMem(), merged_memory()); mms.next_non_empty2(); ) {
2476     if (mms.is_empty()) {
2477       // get a copy of the base memory, and patch just this one input
2478       const TypePtr* adr_type = mms.adr_type(C);
2479       Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
2480       assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
2481       gvn().set_type_bottom(phi);
2482       phi->del_req(phi->req()-1);  // prepare to re-patch
2483       mms.set_memory(phi);
2484     }
2485     mms.memory()->add_req(mms.memory2());
2486   }
2487 
2488   if (_first_return) {
2489     _exits.map()->transfer_replaced_nodes_from(map(), _new_idx);
2490     _first_return = false;
2491   } else {
2492     _exits.map()->merge_replaced_nodes_with(map());
2493   }
2494 
2495   stop_and_kill_map();          // This CFG path dies here
2496 }
2497 
2498 
2499 //------------------------------add_safepoint----------------------------------
2500 void Parse::add_safepoint() {
2501   uint parms = TypeFunc::Parms+1;
2502 
2503   // Clear out dead values from the debug info.
2504   kill_dead_locals();
2505 
2506   // Clone the JVM State
2507   SafePointNode *sfpnt = new SafePointNode(parms, nullptr);
2508 
2509   // Capture memory state BEFORE a SafePoint.  Since we can block at a
2510   // SafePoint we need our GC state to be safe; i.e. we need all our current
2511   // write barriers (card marks) to not float down after the SafePoint so we
2512   // must read raw memory.  Likewise we need all oop stores to match the card
2513   // marks.  If deopt can happen, we need ALL stores (we need the correct JVM
2514   // state on a deopt).
2515 
2516   // We do not need to WRITE the memory state after a SafePoint.  The control
2517   // edge will keep card-marks and oop-stores from floating up from below a
2518   // SafePoint and our true dependency added here will keep them from floating
2519   // down below a SafePoint.
2520 
2521   // Clone the current memory state
2522   Node* mem = MergeMemNode::make(map()->memory());
2523 
2524   mem = _gvn.transform(mem);
2525 
2526   // Pass control through the safepoint
2527   sfpnt->init_req(TypeFunc::Control  , control());
2528   // Fix edges normally used by a call
2529   sfpnt->init_req(TypeFunc::I_O      , top() );
2530   sfpnt->init_req(TypeFunc::Memory   , mem   );
2531   sfpnt->init_req(TypeFunc::ReturnAdr, top() );
2532   sfpnt->init_req(TypeFunc::FramePtr , top() );
2533 
2534   // Create a node for the polling address
2535   Node *polladr;
2536   Node *thread = _gvn.transform(new ThreadLocalNode());
2537   Node *polling_page_load_addr = _gvn.transform(basic_plus_adr(top(), thread, in_bytes(JavaThread::polling_page_offset())));
2538   polladr = make_load(control(), polling_page_load_addr, TypeRawPtr::BOTTOM, T_ADDRESS, MemNode::unordered);
2539   sfpnt->init_req(TypeFunc::Parms+0, _gvn.transform(polladr));
2540 
2541   // Fix up the JVM State edges
2542   add_safepoint_edges(sfpnt);
2543   Node *transformed_sfpnt = _gvn.transform(sfpnt);
2544   set_control(transformed_sfpnt);
2545 
2546   // Provide an edge from root to safepoint.  This makes the safepoint
2547   // appear useful until the parse has completed.
2548   if (transformed_sfpnt->is_SafePoint()) {
2549     assert(C->root() != nullptr, "Expect parse is still valid");
2550     C->root()->add_prec(transformed_sfpnt);
2551   }
2552 }
2553 
2554 #ifndef PRODUCT
2555 //------------------------show_parse_info--------------------------------------
2556 void Parse::show_parse_info() {
2557   InlineTree* ilt = nullptr;
2558   if (C->ilt() != nullptr) {
2559     JVMState* caller_jvms = is_osr_parse() ? caller()->caller() : caller();
2560     ilt = InlineTree::find_subtree_from_root(C->ilt(), caller_jvms, method());
2561   }
2562   if (PrintCompilation && Verbose) {
2563     if (depth() == 1) {
2564       if( ilt->count_inlines() ) {
2565         tty->print("    __inlined %d (%d bytes)", ilt->count_inlines(),
2566                      ilt->count_inline_bcs());
2567         tty->cr();
2568       }
2569     } else {
2570       if (method()->is_synchronized())         tty->print("s");
2571       if (method()->has_exception_handlers())  tty->print("!");
2572       // Check this is not the final compiled version
2573       if (C->trap_can_recompile()) {
2574         tty->print("-");
2575       } else {
2576         tty->print(" ");
2577       }
2578       method()->print_short_name();
2579       if (is_osr_parse()) {
2580         tty->print(" @ %d", osr_bci());
2581       }
2582       tty->print(" (%d bytes)",method()->code_size());
2583       if (ilt->count_inlines()) {
2584         tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2585                    ilt->count_inline_bcs());
2586       }
2587       tty->cr();
2588     }
2589   }
2590   if (PrintOpto && (depth() == 1 || PrintOptoInlining)) {
2591     // Print that we succeeded; suppress this message on the first osr parse.
2592 
2593     if (method()->is_synchronized())         tty->print("s");
2594     if (method()->has_exception_handlers())  tty->print("!");
2595     // Check this is not the final compiled version
2596     if (C->trap_can_recompile() && depth() == 1) {
2597       tty->print("-");
2598     } else {
2599       tty->print(" ");
2600     }
2601     if( depth() != 1 ) { tty->print("   "); }  // missing compile count
2602     for (int i = 1; i < depth(); ++i) { tty->print("  "); }
2603     method()->print_short_name();
2604     if (is_osr_parse()) {
2605       tty->print(" @ %d", osr_bci());
2606     }
2607     if (ilt->caller_bci() != -1) {
2608       tty->print(" @ %d", ilt->caller_bci());
2609     }
2610     tty->print(" (%d bytes)",method()->code_size());
2611     if (ilt->count_inlines()) {
2612       tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2613                  ilt->count_inline_bcs());
2614     }
2615     tty->cr();
2616   }
2617 }
2618 
2619 
2620 //------------------------------dump-------------------------------------------
2621 // Dump information associated with the bytecodes of current _method
2622 void Parse::dump() {
2623   if( method() != nullptr ) {
2624     // Iterate over bytecodes
2625     ciBytecodeStream iter(method());
2626     for( Bytecodes::Code bc = iter.next(); bc != ciBytecodeStream::EOBC() ; bc = iter.next() ) {
2627       dump_bci( iter.cur_bci() );
2628       tty->cr();
2629     }
2630   }
2631 }
2632 
2633 // Dump information associated with a byte code index, 'bci'
2634 void Parse::dump_bci(int bci) {
2635   // Output info on merge-points, cloning, and within _jsr..._ret
2636   // NYI
2637   tty->print(" bci:%d", bci);
2638 }
2639 
2640 #endif