1 /*
   2  * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "ci/ciConstant.hpp"
  27 #include "ci/ciField.hpp"
  28 #include "ci/ciMethod.hpp"
  29 #include "ci/ciMethodData.hpp"
  30 #include "ci/ciObjArrayKlass.hpp"
  31 #include "ci/ciStreams.hpp"
  32 #include "ci/ciTypeArrayKlass.hpp"
  33 #include "ci/ciTypeFlow.hpp"
  34 #include "ci/ciValueKlass.hpp"
  35 #include "compiler/compileLog.hpp"
  36 #include "interpreter/bytecode.hpp"
  37 #include "interpreter/bytecodes.hpp"
  38 #include "memory/allocation.inline.hpp"
  39 #include "memory/resourceArea.hpp"
  40 #include "oops/oop.inline.hpp"
  41 #include "opto/compile.hpp"
  42 #include "opto/node.hpp"
  43 #include "runtime/deoptimization.hpp"
  44 #include "utilities/growableArray.hpp"
  45 
  46 // ciTypeFlow::JsrSet
  47 //
  48 // A JsrSet represents some set of JsrRecords.  This class
  49 // is used to record a set of all jsr routines which we permit
  50 // execution to return (ret) from.
  51 //
  52 // During abstract interpretation, JsrSets are used to determine
  53 // whether two paths which reach a given block are unique, and
  54 // should be cloned apart, or are compatible, and should merge
  55 // together.
  56 
  57 // ------------------------------------------------------------------
  58 // ciTypeFlow::JsrSet::JsrSet
  59 ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) {
  60   if (arena != NULL) {
  61     // Allocate growable array in Arena.
  62     _set = new (arena) GrowableArray<JsrRecord*>(arena, default_len, 0, NULL);
  63   } else {
  64     // Allocate growable array in current ResourceArea.
  65     _set = new GrowableArray<JsrRecord*>(4, 0, NULL, false);
  66   }
  67 }
  68 
  69 // ------------------------------------------------------------------
  70 // ciTypeFlow::JsrSet::copy_into
  71 void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
  72   int len = size();
  73   jsrs->_set->clear();
  74   for (int i = 0; i < len; i++) {
  75     jsrs->_set->append(_set->at(i));
  76   }
  77 }
  78 
  79 // ------------------------------------------------------------------
  80 // ciTypeFlow::JsrSet::is_compatible_with
  81 //
  82 // !!!! MISGIVINGS ABOUT THIS... disregard
  83 //
  84 // Is this JsrSet compatible with some other JsrSet?
  85 //
  86 // In set-theoretic terms, a JsrSet can be viewed as a partial function
  87 // from entry addresses to return addresses.  Two JsrSets A and B are
  88 // compatible iff
  89 //
  90 //   For any x,
  91 //   A(x) defined and B(x) defined implies A(x) == B(x)
  92 //
  93 // Less formally, two JsrSets are compatible when they have identical
  94 // return addresses for any entry addresses they share in common.
  95 bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
  96   // Walk through both sets in parallel.  If the same entry address
  97   // appears in both sets, then the return address must match for
  98   // the sets to be compatible.
  99   int size1 = size();
 100   int size2 = other->size();
 101 
 102   // Special case.  If nothing is on the jsr stack, then there can
 103   // be no ret.
 104   if (size2 == 0) {
 105     return true;
 106   } else if (size1 != size2) {
 107     return false;
 108   } else {
 109     for (int i = 0; i < size1; i++) {
 110       JsrRecord* record1 = record_at(i);
 111       JsrRecord* record2 = other->record_at(i);
 112       if (record1->entry_address() != record2->entry_address() ||
 113           record1->return_address() != record2->return_address()) {
 114         return false;
 115       }
 116     }
 117     return true;
 118   }
 119 
 120 #if 0
 121   int pos1 = 0;
 122   int pos2 = 0;
 123   int size1 = size();
 124   int size2 = other->size();
 125   while (pos1 < size1 && pos2 < size2) {
 126     JsrRecord* record1 = record_at(pos1);
 127     JsrRecord* record2 = other->record_at(pos2);
 128     int entry1 = record1->entry_address();
 129     int entry2 = record2->entry_address();
 130     if (entry1 < entry2) {
 131       pos1++;
 132     } else if (entry1 > entry2) {
 133       pos2++;
 134     } else {
 135       if (record1->return_address() == record2->return_address()) {
 136         pos1++;
 137         pos2++;
 138       } else {
 139         // These two JsrSets are incompatible.
 140         return false;
 141       }
 142     }
 143   }
 144   // The two JsrSets agree.
 145   return true;
 146 #endif
 147 }
 148 
 149 // ------------------------------------------------------------------
 150 // ciTypeFlow::JsrSet::insert_jsr_record
 151 //
 152 // Insert the given JsrRecord into the JsrSet, maintaining the order
 153 // of the set and replacing any element with the same entry address.
 154 void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
 155   int len = size();
 156   int entry = record->entry_address();
 157   int pos = 0;
 158   for ( ; pos < len; pos++) {
 159     JsrRecord* current = record_at(pos);
 160     if (entry == current->entry_address()) {
 161       // Stomp over this entry.
 162       _set->at_put(pos, record);
 163       assert(size() == len, "must be same size");
 164       return;
 165     } else if (entry < current->entry_address()) {
 166       break;
 167     }
 168   }
 169 
 170   // Insert the record into the list.
 171   JsrRecord* swap = record;
 172   JsrRecord* temp = NULL;
 173   for ( ; pos < len; pos++) {
 174     temp = _set->at(pos);
 175     _set->at_put(pos, swap);
 176     swap = temp;
 177   }
 178   _set->append(swap);
 179   assert(size() == len+1, "must be larger");
 180 }
 181 
 182 // ------------------------------------------------------------------
 183 // ciTypeFlow::JsrSet::remove_jsr_record
 184 //
 185 // Remove the JsrRecord with the given return address from the JsrSet.
 186 void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
 187   int len = size();
 188   for (int i = 0; i < len; i++) {
 189     if (record_at(i)->return_address() == return_address) {
 190       // We have found the proper entry.  Remove it from the
 191       // JsrSet and exit.
 192       for (int j = i+1; j < len ; j++) {
 193         _set->at_put(j-1, _set->at(j));
 194       }
 195       _set->trunc_to(len-1);
 196       assert(size() == len-1, "must be smaller");
 197       return;
 198     }
 199   }
 200   assert(false, "verify: returning from invalid subroutine");
 201 }
 202 
 203 // ------------------------------------------------------------------
 204 // ciTypeFlow::JsrSet::apply_control
 205 //
 206 // Apply the effect of a control-flow bytecode on the JsrSet.  The
 207 // only bytecodes that modify the JsrSet are jsr and ret.
 208 void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
 209                                        ciBytecodeStream* str,
 210                                        ciTypeFlow::StateVector* state) {
 211   Bytecodes::Code code = str->cur_bc();
 212   if (code == Bytecodes::_jsr) {
 213     JsrRecord* record =
 214       analyzer->make_jsr_record(str->get_dest(), str->next_bci());
 215     insert_jsr_record(record);
 216   } else if (code == Bytecodes::_jsr_w) {
 217     JsrRecord* record =
 218       analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
 219     insert_jsr_record(record);
 220   } else if (code == Bytecodes::_ret) {
 221     Cell local = state->local(str->get_index());
 222     ciType* return_address = state->type_at(local);
 223     assert(return_address->is_return_address(), "verify: wrong type");
 224     if (size() == 0) {
 225       // Ret-state underflow:  Hit a ret w/o any previous jsrs.  Bail out.
 226       // This can happen when a loop is inside a finally clause (4614060).
 227       analyzer->record_failure("OSR in finally clause");
 228       return;
 229     }
 230     remove_jsr_record(return_address->as_return_address()->bci());
 231   }
 232 }
 233 
 234 #ifndef PRODUCT
 235 // ------------------------------------------------------------------
 236 // ciTypeFlow::JsrSet::print_on
 237 void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
 238   st->print("{ ");
 239   int num_elements = size();
 240   if (num_elements > 0) {
 241     int i = 0;
 242     for( ; i < num_elements - 1; i++) {
 243       _set->at(i)->print_on(st);
 244       st->print(", ");
 245     }
 246     _set->at(i)->print_on(st);
 247     st->print(" ");
 248   }
 249   st->print("}");
 250 }
 251 #endif
 252 
 253 // ciTypeFlow::StateVector
 254 //
 255 // A StateVector summarizes the type information at some point in
 256 // the program.
 257 
 258 // ------------------------------------------------------------------
 259 // ciTypeFlow::StateVector::type_meet
 260 //
 261 // Meet two types.
 262 //
 263 // The semi-lattice of types use by this analysis are modeled on those
 264 // of the verifier.  The lattice is as follows:
 265 //
 266 //        top_type() >= all non-extremal types >= bottom_type
 267 //                             and
 268 //   Every primitive type is comparable only with itself.  The meet of
 269 //   reference types is determined by their kind: instance class,
 270 //   interface, or array class.  The meet of two types of the same
 271 //   kind is their least common ancestor.  The meet of two types of
 272 //   different kinds is always java.lang.Object.
 273 ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
 274   assert(t1 != t2, "checked in caller");
 275   if (t1->equals(top_type())) {
 276     return t2;
 277   } else if (t2->equals(top_type())) {
 278     return t1;
 279   } else if (t1->is_primitive_type() || t2->is_primitive_type()) {
 280     // Special case null_type.  null_type meet any reference type T
 281     // is T.  null_type meet null_type is null_type.
 282     if (t1->equals(null_type())) {
 283       if (!t2->is_primitive_type() || t2->equals(null_type())) {
 284         return t2;
 285       }
 286     } else if (t2->equals(null_type())) {
 287       if (!t1->is_primitive_type()) {
 288         return t1;
 289       }
 290     }
 291 
 292     // At least one of the two types is a non-top primitive type.
 293     // The other type is not equal to it.  Fall to bottom.
 294     return bottom_type();
 295   } else {
 296     // Both types are non-top non-primitive types.  That is,
 297     // both types are either instanceKlasses or arrayKlasses.
 298     ciKlass* object_klass = analyzer->env()->Object_klass();
 299     ciKlass* k1 = t1->as_klass();
 300     ciKlass* k2 = t2->as_klass();
 301     if (k1->equals(object_klass) || k2->equals(object_klass)) {
 302       return object_klass;
 303     } else if (!k1->is_loaded() || !k2->is_loaded()) {
 304       // Unloaded classes fall to java.lang.Object at a merge.
 305       return object_klass;
 306     } else if (k1->is_interface() != k2->is_interface()) {
 307       // When an interface meets a non-interface, we get Object;
 308       // This is what the verifier does.
 309       return object_klass;
 310     } else if (k1->is_array_klass() || k2->is_array_klass()) {
 311       // When an array meets a non-array, we get Object.
 312       // When objArray meets typeArray, we also get Object.
 313       // And when typeArray meets different typeArray, we again get Object.
 314       // But when objArray meets objArray, we look carefully at element types.
 315       if (k1->is_obj_array_klass() && k2->is_obj_array_klass()) {
 316         // Meet the element types, then construct the corresponding array type.
 317         ciKlass* elem1 = k1->as_obj_array_klass()->element_klass();
 318         ciKlass* elem2 = k2->as_obj_array_klass()->element_klass();
 319         ciKlass* elem  = type_meet_internal(elem1, elem2, analyzer)->as_klass();
 320         // Do an easy shortcut if one type is a super of the other.
 321         if (elem == elem1) {
 322           assert(k1 == ciObjArrayKlass::make(elem), "shortcut is OK");
 323           return k1;
 324         } else if (elem == elem2) {
 325           assert(k2 == ciObjArrayKlass::make(elem), "shortcut is OK");
 326           return k2;
 327         } else {
 328           return ciObjArrayKlass::make(elem);
 329         }
 330       } else {
 331         return object_klass;
 332       }
 333     } else {
 334       // Must be two plain old instance klasses.
 335       assert(k1->is_instance_klass(), "previous cases handle non-instances");
 336       assert(k2->is_instance_klass(), "previous cases handle non-instances");
 337       return k1->least_common_ancestor(k2);
 338     }
 339   }
 340 }
 341 
 342 
 343 // ------------------------------------------------------------------
 344 // ciTypeFlow::StateVector::StateVector
 345 //
 346 // Build a new state vector
 347 ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
 348   _outer = analyzer;
 349   _stack_size = -1;
 350   _monitor_count = -1;
 351   // Allocate the _types array
 352   int max_cells = analyzer->max_cells();
 353   _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
 354   for (int i=0; i<max_cells; i++) {
 355     _types[i] = top_type();
 356   }
 357   _trap_bci = -1;
 358   _trap_index = 0;
 359   _def_locals.clear();
 360 }
 361 
 362 
 363 // ------------------------------------------------------------------
 364 // ciTypeFlow::get_start_state
 365 //
 366 // Set this vector to the method entry state.
 367 const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
 368   StateVector* state = new StateVector(this);
 369   if (is_osr_flow()) {
 370     ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
 371     if (non_osr_flow->failing()) {
 372       record_failure(non_osr_flow->failure_reason());
 373       return NULL;
 374     }
 375     JsrSet* jsrs = new JsrSet(NULL, 16);
 376     Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
 377     if (non_osr_block == NULL) {
 378       record_failure("cannot reach OSR point");
 379       return NULL;
 380     }
 381     // load up the non-OSR state at this point
 382     non_osr_block->copy_state_into(state);
 383     int non_osr_start = non_osr_block->start();
 384     if (non_osr_start != start_bci()) {
 385       // must flow forward from it
 386       if (CITraceTypeFlow) {
 387         tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
 388       }
 389       Block* block = block_at(non_osr_start, jsrs);
 390       assert(block->limit() == start_bci(), "must flow forward to start");
 391       flow_block(block, state, jsrs);
 392     }
 393     return state;
 394     // Note:  The code below would be an incorrect for an OSR flow,
 395     // even if it were possible for an OSR entry point to be at bci zero.
 396   }
 397   // "Push" the method signature into the first few locals.
 398   state->set_stack_size(-max_locals());
 399   if (!method()->is_static()) {
 400     state->push(method()->holder());
 401     assert(state->tos() == state->local(0), "");
 402   }
 403   for (ciSignatureStream str(method()->signature());
 404        !str.at_return_type();
 405        str.next()) {
 406     state->push_translate(str.type());
 407   }
 408   // Set the rest of the locals to bottom.
 409   Cell cell = state->next_cell(state->tos());
 410   state->set_stack_size(0);
 411   int limit = state->limit_cell();
 412   for (; cell < limit; cell = state->next_cell(cell)) {
 413     state->set_type_at(cell, state->bottom_type());
 414   }
 415   // Lock an object, if necessary.
 416   state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
 417   return state;
 418 }
 419 
 420 // ------------------------------------------------------------------
 421 // ciTypeFlow::StateVector::copy_into
 422 //
 423 // Copy our value into some other StateVector
 424 void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
 425 const {
 426   copy->set_stack_size(stack_size());
 427   copy->set_monitor_count(monitor_count());
 428   Cell limit = limit_cell();
 429   for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 430     copy->set_type_at(c, type_at(c));
 431   }
 432 }
 433 
 434 // ------------------------------------------------------------------
 435 // ciTypeFlow::StateVector::meet
 436 //
 437 // Meets this StateVector with another, destructively modifying this
 438 // one.  Returns true if any modification takes place.
 439 bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
 440   if (monitor_count() == -1) {
 441     set_monitor_count(incoming->monitor_count());
 442   }
 443   assert(monitor_count() == incoming->monitor_count(), "monitors must match");
 444 
 445   if (stack_size() == -1) {
 446     set_stack_size(incoming->stack_size());
 447     Cell limit = limit_cell();
 448     #ifdef ASSERT
 449     { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 450         assert(type_at(c) == top_type(), "");
 451     } }
 452     #endif
 453     // Make a simple copy of the incoming state.
 454     for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 455       set_type_at(c, incoming->type_at(c));
 456     }
 457     return true;  // it is always different the first time
 458   }
 459 #ifdef ASSERT
 460   if (stack_size() != incoming->stack_size()) {
 461     _outer->method()->print_codes();
 462     tty->print_cr("!!!! Stack size conflict");
 463     tty->print_cr("Current state:");
 464     print_on(tty);
 465     tty->print_cr("Incoming state:");
 466     ((StateVector*)incoming)->print_on(tty);
 467   }
 468 #endif
 469   assert(stack_size() == incoming->stack_size(), "sanity");
 470 
 471   bool different = false;
 472   Cell limit = limit_cell();
 473   for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 474     ciType* t1 = type_at(c);
 475     ciType* t2 = incoming->type_at(c);
 476     if (!t1->equals(t2)) {
 477       ciType* new_type = type_meet(t1, t2);
 478       if (!t1->equals(new_type)) {
 479         set_type_at(c, new_type);
 480         different = true;
 481       }
 482     }
 483   }
 484   return different;
 485 }
 486 
 487 // ------------------------------------------------------------------
 488 // ciTypeFlow::StateVector::meet_exception
 489 //
 490 // Meets this StateVector with another, destructively modifying this
 491 // one.  The incoming state is coming via an exception.  Returns true
 492 // if any modification takes place.
 493 bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
 494                                      const ciTypeFlow::StateVector* incoming) {
 495   if (monitor_count() == -1) {
 496     set_monitor_count(incoming->monitor_count());
 497   }
 498   assert(monitor_count() == incoming->monitor_count(), "monitors must match");
 499 
 500   if (stack_size() == -1) {
 501     set_stack_size(1);
 502   }
 503 
 504   assert(stack_size() ==  1, "must have one-element stack");
 505 
 506   bool different = false;
 507 
 508   // Meet locals from incoming array.
 509   Cell limit = local(_outer->max_locals()-1);
 510   for (Cell c = start_cell(); c <= limit; c = next_cell(c)) {
 511     ciType* t1 = type_at(c);
 512     ciType* t2 = incoming->type_at(c);
 513     if (!t1->equals(t2)) {
 514       ciType* new_type = type_meet(t1, t2);
 515       if (!t1->equals(new_type)) {
 516         set_type_at(c, new_type);
 517         different = true;
 518       }
 519     }
 520   }
 521 
 522   // Handle stack separately.  When an exception occurs, the
 523   // only stack entry is the exception instance.
 524   ciType* tos_type = type_at_tos();
 525   if (!tos_type->equals(exc)) {
 526     ciType* new_type = type_meet(tos_type, exc);
 527     if (!tos_type->equals(new_type)) {
 528       set_type_at_tos(new_type);
 529       different = true;
 530     }
 531   }
 532 
 533   return different;
 534 }
 535 
 536 // ------------------------------------------------------------------
 537 // ciTypeFlow::StateVector::push_translate
 538 void ciTypeFlow::StateVector::push_translate(ciType* type) {
 539   BasicType basic_type = type->basic_type();
 540   if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
 541       basic_type == T_BYTE    || basic_type == T_SHORT) {
 542     push_int();
 543   } else {
 544     push(type);
 545     if (type->is_two_word()) {
 546       push(half_type(type));
 547     }
 548   }
 549 }
 550 
 551 // ------------------------------------------------------------------
 552 // ciTypeFlow::StateVector::do_aload
 553 void ciTypeFlow::StateVector::do_aload(ciBytecodeStream* str) {
 554   pop_int();
 555   ciArrayKlass* array_klass = pop_objOrValueArray();
 556   if (array_klass == NULL) {
 557     // Did aload on a null reference; push a null and ignore the exception.
 558     // This instruction will never continue normally.  All we have to do
 559     // is report a value that will meet correctly with any downstream
 560     // reference types on paths that will truly be executed.  This null type
 561     // meets with any reference type to yield that same reference type.
 562     // (The compiler will generate an unconditional exception here.)
 563     push(null_type());
 564     return;
 565   }
 566   if (!array_klass->is_loaded()) {
 567     // Only fails for some -Xcomp runs
 568     trap(str, array_klass,
 569          Deoptimization::make_trap_request
 570          (Deoptimization::Reason_unloaded,
 571           Deoptimization::Action_reinterpret));
 572     return;
 573   }
 574   ciKlass* element_klass = array_klass->element_klass();
 575   if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
 576     Untested("unloaded array element class in ciTypeFlow");
 577     trap(str, element_klass,
 578          Deoptimization::make_trap_request
 579          (Deoptimization::Reason_unloaded,
 580           Deoptimization::Action_reinterpret));
 581   } else {
 582     push_object(element_klass);
 583   }
 584 }
 585 
 586 
 587 // ------------------------------------------------------------------
 588 // ciTypeFlow::StateVector::do_checkcast
 589 void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
 590   bool will_link;
 591   ciKlass* klass = str->get_klass(will_link);
 592   if (!will_link) {
 593     // VM's interpreter will not load 'klass' if object is NULL.
 594     // Type flow after this block may still be needed in two situations:
 595     // 1) C2 uses do_null_assert() and continues compilation for later blocks
 596     // 2) C2 does an OSR compile in a later block (see bug 4778368).
 597     pop_object();
 598     do_null_assert(klass);
 599   } else {
 600     pop_object();
 601     push_object(klass);
 602   }
 603 }
 604 
 605 // ------------------------------------------------------------------
 606 // ciTypeFlow::StateVector::do_getfield
 607 void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
 608   // could add assert here for type of object.
 609   pop_object();
 610   do_getstatic(str);
 611 }
 612 
 613 // ------------------------------------------------------------------
 614 // ciTypeFlow::StateVector::do_getstatic
 615 void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
 616   bool will_link;
 617   ciField* field = str->get_field(will_link);
 618   if (!will_link) {
 619     trap(str, field->holder(), str->get_field_holder_index());
 620   } else {
 621     ciType* field_type = field->type();
 622     if (!field_type->is_loaded()) {
 623       // Normally, we need the field's type to be loaded if we are to
 624       // do anything interesting with its value.
 625       // We used to do this:  trap(str, str->get_field_signature_index());
 626       //
 627       // There is one good reason not to trap here.  Execution can
 628       // get past this "getfield" or "getstatic" if the value of
 629       // the field is null.  As long as the value is null, the class
 630       // does not need to be loaded!  The compiler must assume that
 631       // the value of the unloaded class reference is null; if the code
 632       // ever sees a non-null value, loading has occurred.
 633       //
 634       // This actually happens often enough to be annoying.  If the
 635       // compiler throws an uncommon trap at this bytecode, you can
 636       // get an endless loop of recompilations, when all the code
 637       // needs to do is load a series of null values.  Also, a trap
 638       // here can make an OSR entry point unreachable, triggering the
 639       // assert on non_osr_block in ciTypeFlow::get_start_state.
 640       // (See bug 4379915.)
 641       do_null_assert(field_type->as_klass());
 642     } else {
 643       push_translate(field_type);
 644     }
 645   }
 646 }
 647 
 648 // ------------------------------------------------------------------
 649 // ciTypeFlow::StateVector::do_invoke
 650 void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
 651                                         bool has_receiver) {
 652   bool will_link;
 653   ciSignature* declared_signature = NULL;
 654   ciMethod* callee = str->get_method(will_link, &declared_signature);
 655   assert(declared_signature != NULL, "cannot be null");
 656   if (!will_link) {
 657     // We weren't able to find the method.
 658     if (str->cur_bc() == Bytecodes::_invokedynamic) {
 659       trap(str, NULL,
 660            Deoptimization::make_trap_request
 661            (Deoptimization::Reason_uninitialized,
 662             Deoptimization::Action_reinterpret));
 663     } else {
 664       ciKlass* unloaded_holder = callee->holder();
 665       trap(str, unloaded_holder, str->get_method_holder_index());
 666     }
 667   } else {
 668     // We are using the declared signature here because it might be
 669     // different from the callee signature (Cf. invokedynamic and
 670     // invokehandle).
 671     ciSignatureStream sigstr(declared_signature);
 672     const int arg_size = declared_signature->size();
 673     const int stack_base = stack_size() - arg_size;
 674     int i = 0;
 675     for( ; !sigstr.at_return_type(); sigstr.next()) {
 676       ciType* type = sigstr.type();
 677       ciType* stack_type = type_at(stack(stack_base + i++));
 678       // Do I want to check this type?
 679       // assert(stack_type->is_subtype_of(type), "bad type for field value");
 680       if (type->is_two_word()) {
 681         ciType* stack_type2 = type_at(stack(stack_base + i++));
 682         assert(stack_type2->equals(half_type(type)), "must be 2nd half");
 683       }
 684     }
 685     assert(arg_size == i, "must match");
 686     for (int j = 0; j < arg_size; j++) {
 687       pop();
 688     }
 689     if (has_receiver) {
 690       // Check this?
 691       pop_object();
 692     }
 693     assert(!sigstr.is_done(), "must have return type");
 694     ciType* return_type = sigstr.type();
 695     if (!return_type->is_void()) {
 696       if (!return_type->is_loaded()) {
 697         // As in do_getstatic(), generally speaking, we need the return type to
 698         // be loaded if we are to do anything interesting with its value.
 699         // We used to do this:  trap(str, str->get_method_signature_index());
 700         //
 701         // We do not trap here since execution can get past this invoke if
 702         // the return value is null.  As long as the value is null, the class
 703         // does not need to be loaded!  The compiler must assume that
 704         // the value of the unloaded class reference is null; if the code
 705         // ever sees a non-null value, loading has occurred.
 706         //
 707         // See do_getstatic() for similar explanation, as well as bug 4684993.
 708         do_null_assert(return_type->as_klass());
 709       } else {
 710         push_translate(return_type);
 711       }
 712     }
 713   }
 714 }
 715 
 716 // ------------------------------------------------------------------
 717 // ciTypeFlow::StateVector::do_jsr
 718 void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
 719   push(ciReturnAddress::make(str->next_bci()));
 720 }
 721 
 722 // ------------------------------------------------------------------
 723 // ciTypeFlow::StateVector::do_ldc
 724 void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
 725   ciConstant con = str->get_constant();
 726   BasicType basic_type = con.basic_type();
 727   if (basic_type == T_ILLEGAL) {
 728     // OutOfMemoryError in the CI while loading constant
 729     push_null();
 730     outer()->record_failure("ldc did not link");
 731     return;
 732   }
 733   if (basic_type == T_OBJECT || basic_type == T_ARRAY) {
 734     ciObject* obj = con.as_object();
 735     if (obj->is_null_object()) {
 736       push_null();
 737     } else {
 738       assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
 739       push_object(obj->klass());
 740     }
 741   } else {
 742     push_translate(ciType::make(basic_type));
 743   }
 744 }
 745 
 746 // ------------------------------------------------------------------
 747 // ciTypeFlow::StateVector::do_multianewarray
 748 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
 749   int dimensions = str->get_dimensions();
 750   bool will_link;
 751   ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
 752   if (!will_link) {
 753     trap(str, array_klass, str->get_klass_index());
 754   } else {
 755     for (int i = 0; i < dimensions; i++) {
 756       pop_int();
 757     }
 758     push_object(array_klass);
 759   }
 760 }
 761 
 762 // ------------------------------------------------------------------
 763 // ciTypeFlow::StateVector::do_new
 764 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
 765   bool will_link;
 766   ciKlass* klass = str->get_klass(will_link);
 767   if (!will_link || str->is_unresolved_klass()) {
 768     trap(str, klass, str->get_klass_index());
 769   } else {
 770     push_object(klass);
 771   }
 772 }
 773 
 774 // ------------------------------------------------------------------
 775 // ciTypeFlow::StateVector::do_vdefault
 776 void ciTypeFlow::StateVector::do_vdefault(ciBytecodeStream* str) {
 777   bool will_link;
 778   ciKlass* klass = str->get_klass(will_link);
 779   assert(klass->is_valuetype(), "should be value type");
 780   if (!will_link) {
 781     trap(str, klass, str->get_klass_index());
 782   } else {
 783     push_object(klass);
 784   }
 785 }
 786 
 787 // ------------------------------------------------------------------
 788 // ciTypeFlow::StateVector::do_vwithfield
 789 void ciTypeFlow::StateVector::do_vwithfield(ciBytecodeStream* str) {
 790   bool will_link;
 791   ciField* field = str->get_field(will_link);
 792   ciKlass* klass = field->holder();
 793   assert(klass->is_valuetype(), "should be value type");
 794   if (!will_link) {
 795     trap(str, klass, str->get_field_holder_index());
 796   } else {
 797     ciType* type = pop_value();
 798     ciType* field_type = field->type();
 799     assert(field_type->is_loaded(), "field type must be loaded");
 800     if (field_type->is_two_word()) {
 801       ciType* type2 = pop_value();
 802       assert(type2->is_two_word(), "must be 2nd half");
 803       assert(type == half_type(type2), "must be 2nd half");
 804     }
 805     pop_object();
 806     push_object(klass);
 807   }
 808 }
 809 
 810 // ------------------------------------------------------------------
 811 // ciTypeFlow::StateVector::do_newarray
 812 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
 813   pop_int();
 814   ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
 815   push_object(klass);
 816 }
 817 
 818 // ------------------------------------------------------------------
 819 // ciTypeFlow::StateVector::do_putfield
 820 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
 821   do_putstatic(str);
 822   if (_trap_bci != -1)  return;  // unloaded field holder, etc.
 823   // could add assert here for type of object.
 824   pop_object();
 825 }
 826 
 827 // ------------------------------------------------------------------
 828 // ciTypeFlow::StateVector::do_putstatic
 829 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
 830   bool will_link;
 831   ciField* field = str->get_field(will_link);
 832   if (!will_link) {
 833     trap(str, field->holder(), str->get_field_holder_index());
 834   } else {
 835     ciType* field_type = field->type();
 836     ciType* type = pop_value();
 837     // Do I want to check this type?
 838     //      assert(type->is_subtype_of(field_type), "bad type for field value");
 839     if (field_type->is_two_word()) {
 840       ciType* type2 = pop_value();
 841       assert(type2->is_two_word(), "must be 2nd half");
 842       assert(type == half_type(type2), "must be 2nd half");
 843     }
 844   }
 845 }
 846 
 847 // ------------------------------------------------------------------
 848 // ciTypeFlow::StateVector::do_ret
 849 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
 850   Cell index = local(str->get_index());
 851 
 852   ciType* address = type_at(index);
 853   assert(address->is_return_address(), "bad return address");
 854   set_type_at(index, bottom_type());
 855 }
 856 
 857 void ciTypeFlow::StateVector::do_vunbox(ciBytecodeStream* str) {
 858   bool will_link;
 859   ciKlass* klass = str->get_klass(will_link);
 860   // TODO: Handle case when class is not loaded.
 861   guarantee(will_link, "Class to which the value-capable class will unbox to must be loaded for JIT compilation");
 862   assert(klass->is_instance_klass(), "must be an instance class");
 863   pop_object();
 864   push_object(klass->as_instance_klass());
 865 }
 866 
 867 void ciTypeFlow::StateVector::do_vbox(ciBytecodeStream* str) {
 868   bool will_link;
 869   ciKlass* klass = str->get_klass(will_link);
 870   // TODO: Handle case when class is not loaded.
 871   guarantee(will_link, "Class to which value type will box to must be loaded for JIT compilation");
 872   assert(klass->is_instance_klass(), "must be an instance class");
 873   pop_object();
 874   push_object(klass->as_instance_klass());
 875 }
 876 
 877 // ------------------------------------------------------------------
 878 // ciTypeFlow::StateVector::trap
 879 //
 880 // Stop interpretation of this path with a trap.
 881 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
 882   _trap_bci = str->cur_bci();
 883   _trap_index = index;
 884 
 885   // Log information about this trap:
 886   CompileLog* log = outer()->env()->log();
 887   if (log != NULL) {
 888     int mid = log->identify(outer()->method());
 889     int kid = (klass == NULL)? -1: log->identify(klass);
 890     log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
 891     char buf[100];
 892     log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
 893                                                           index));
 894     if (kid >= 0)
 895       log->print(" klass='%d'", kid);
 896     log->end_elem();
 897   }
 898 }
 899 
 900 // ------------------------------------------------------------------
 901 // ciTypeFlow::StateVector::do_null_assert
 902 // Corresponds to graphKit::do_null_assert.
 903 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
 904   if (unloaded_klass->is_loaded()) {
 905     // We failed to link, but we can still compute with this class,
 906     // since it is loaded somewhere.  The compiler will uncommon_trap
 907     // if the object is not null, but the typeflow pass can not assume
 908     // that the object will be null, otherwise it may incorrectly tell
 909     // the parser that an object is known to be null. 4761344, 4807707
 910     push_object(unloaded_klass);
 911   } else {
 912     // The class is not loaded anywhere.  It is safe to model the
 913     // null in the typestates, because we can compile in a null check
 914     // which will deoptimize us if someone manages to load the
 915     // class later.
 916     push_null();
 917   }
 918 }
 919 
 920 
 921 // ------------------------------------------------------------------
 922 // ciTypeFlow::StateVector::apply_one_bytecode
 923 //
 924 // Apply the effect of one bytecode to this StateVector
 925 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
 926   _trap_bci = -1;
 927   _trap_index = 0;
 928 
 929   if (CITraceTypeFlow) {
 930     tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
 931                   Bytecodes::name(str->cur_bc()));
 932   }
 933 
 934   switch(str->cur_bc()) {
 935   case Bytecodes::_aaload: do_aload(str);                           break;
 936 
 937   case Bytecodes::_aastore:
 938     {
 939       pop_object();
 940       pop_int();
 941       pop_objOrValueArray();
 942       break;
 943     }
 944   case Bytecodes::_aconst_null:
 945     {
 946       push_null();
 947       break;
 948     }
 949   case Bytecodes::_aload:   load_local_object(str->get_index());    break;
 950   case Bytecodes::_aload_0: load_local_object(0);                   break;
 951   case Bytecodes::_aload_1: load_local_object(1);                   break;
 952   case Bytecodes::_aload_2: load_local_object(2);                   break;
 953   case Bytecodes::_aload_3: load_local_object(3);                   break;
 954 
 955   case Bytecodes::_anewarray:
 956     {
 957       pop_int();
 958       bool will_link;
 959       ciKlass* element_klass = str->get_klass(will_link);
 960       if (!will_link) {
 961         trap(str, element_klass, str->get_klass_index());
 962       } else {
 963         push_object(ciArrayKlass::make(element_klass));
 964       }
 965       break;
 966     }
 967   case Bytecodes::_areturn:
 968   case Bytecodes::_ifnonnull:
 969   case Bytecodes::_ifnull:
 970     {
 971       pop_object();
 972       break;
 973     }
 974   case Bytecodes::_monitorenter:
 975     {
 976       pop_object();
 977       set_monitor_count(monitor_count() + 1);
 978       break;
 979     }
 980   case Bytecodes::_monitorexit:
 981     {
 982       pop_object();
 983       assert(monitor_count() > 0, "must be a monitor to exit from");
 984       set_monitor_count(monitor_count() - 1);
 985       break;
 986     }
 987   case Bytecodes::_arraylength:
 988     {
 989       pop_array();
 990       push_int();
 991       break;
 992     }
 993   case Bytecodes::_astore:   store_local_object(str->get_index());  break;
 994   case Bytecodes::_astore_0: store_local_object(0);                 break;
 995   case Bytecodes::_astore_1: store_local_object(1);                 break;
 996   case Bytecodes::_astore_2: store_local_object(2);                 break;
 997   case Bytecodes::_astore_3: store_local_object(3);                 break;
 998 
 999   case Bytecodes::_athrow:
1000     {
1001       NEEDS_CLEANUP;
1002       pop_object();
1003       break;
1004     }
1005   case Bytecodes::_baload:
1006   case Bytecodes::_caload:
1007   case Bytecodes::_iaload:
1008   case Bytecodes::_saload:
1009     {
1010       pop_int();
1011       ciTypeArrayKlass* array_klass = pop_typeArray();
1012       // Put assert here for right type?
1013       push_int();
1014       break;
1015     }
1016   case Bytecodes::_bastore:
1017   case Bytecodes::_castore:
1018   case Bytecodes::_iastore:
1019   case Bytecodes::_sastore:
1020     {
1021       pop_int();
1022       pop_int();
1023       pop_typeArray();
1024       // assert here?
1025       break;
1026     }
1027   case Bytecodes::_bipush:
1028   case Bytecodes::_iconst_m1:
1029   case Bytecodes::_iconst_0:
1030   case Bytecodes::_iconst_1:
1031   case Bytecodes::_iconst_2:
1032   case Bytecodes::_iconst_3:
1033   case Bytecodes::_iconst_4:
1034   case Bytecodes::_iconst_5:
1035   case Bytecodes::_sipush:
1036     {
1037       push_int();
1038       break;
1039     }
1040   case Bytecodes::_checkcast: do_checkcast(str);                  break;
1041 
1042   case Bytecodes::_d2f:
1043     {
1044       pop_double();
1045       push_float();
1046       break;
1047     }
1048   case Bytecodes::_d2i:
1049     {
1050       pop_double();
1051       push_int();
1052       break;
1053     }
1054   case Bytecodes::_d2l:
1055     {
1056       pop_double();
1057       push_long();
1058       break;
1059     }
1060   case Bytecodes::_dadd:
1061   case Bytecodes::_ddiv:
1062   case Bytecodes::_dmul:
1063   case Bytecodes::_drem:
1064   case Bytecodes::_dsub:
1065     {
1066       pop_double();
1067       pop_double();
1068       push_double();
1069       break;
1070     }
1071   case Bytecodes::_daload:
1072     {
1073       pop_int();
1074       ciTypeArrayKlass* array_klass = pop_typeArray();
1075       // Put assert here for right type?
1076       push_double();
1077       break;
1078     }
1079   case Bytecodes::_dastore:
1080     {
1081       pop_double();
1082       pop_int();
1083       pop_typeArray();
1084       // assert here?
1085       break;
1086     }
1087   case Bytecodes::_dcmpg:
1088   case Bytecodes::_dcmpl:
1089     {
1090       pop_double();
1091       pop_double();
1092       push_int();
1093       break;
1094     }
1095   case Bytecodes::_dconst_0:
1096   case Bytecodes::_dconst_1:
1097     {
1098       push_double();
1099       break;
1100     }
1101   case Bytecodes::_dload:   load_local_double(str->get_index());    break;
1102   case Bytecodes::_dload_0: load_local_double(0);                   break;
1103   case Bytecodes::_dload_1: load_local_double(1);                   break;
1104   case Bytecodes::_dload_2: load_local_double(2);                   break;
1105   case Bytecodes::_dload_3: load_local_double(3);                   break;
1106 
1107   case Bytecodes::_dneg:
1108     {
1109       pop_double();
1110       push_double();
1111       break;
1112     }
1113   case Bytecodes::_dreturn:
1114     {
1115       pop_double();
1116       break;
1117     }
1118   case Bytecodes::_dstore:   store_local_double(str->get_index());  break;
1119   case Bytecodes::_dstore_0: store_local_double(0);                 break;
1120   case Bytecodes::_dstore_1: store_local_double(1);                 break;
1121   case Bytecodes::_dstore_2: store_local_double(2);                 break;
1122   case Bytecodes::_dstore_3: store_local_double(3);                 break;
1123 
1124   case Bytecodes::_dup:
1125     {
1126       push(type_at_tos());
1127       break;
1128     }
1129   case Bytecodes::_dup_x1:
1130     {
1131       ciType* value1 = pop_value();
1132       ciType* value2 = pop_value();
1133       push(value1);
1134       push(value2);
1135       push(value1);
1136       break;
1137     }
1138   case Bytecodes::_dup_x2:
1139     {
1140       ciType* value1 = pop_value();
1141       ciType* value2 = pop_value();
1142       ciType* value3 = pop_value();
1143       push(value1);
1144       push(value3);
1145       push(value2);
1146       push(value1);
1147       break;
1148     }
1149   case Bytecodes::_dup2:
1150     {
1151       ciType* value1 = pop_value();
1152       ciType* value2 = pop_value();
1153       push(value2);
1154       push(value1);
1155       push(value2);
1156       push(value1);
1157       break;
1158     }
1159   case Bytecodes::_dup2_x1:
1160     {
1161       ciType* value1 = pop_value();
1162       ciType* value2 = pop_value();
1163       ciType* value3 = pop_value();
1164       push(value2);
1165       push(value1);
1166       push(value3);
1167       push(value2);
1168       push(value1);
1169       break;
1170     }
1171   case Bytecodes::_dup2_x2:
1172     {
1173       ciType* value1 = pop_value();
1174       ciType* value2 = pop_value();
1175       ciType* value3 = pop_value();
1176       ciType* value4 = pop_value();
1177       push(value2);
1178       push(value1);
1179       push(value4);
1180       push(value3);
1181       push(value2);
1182       push(value1);
1183       break;
1184     }
1185   case Bytecodes::_f2d:
1186     {
1187       pop_float();
1188       push_double();
1189       break;
1190     }
1191   case Bytecodes::_f2i:
1192     {
1193       pop_float();
1194       push_int();
1195       break;
1196     }
1197   case Bytecodes::_f2l:
1198     {
1199       pop_float();
1200       push_long();
1201       break;
1202     }
1203   case Bytecodes::_fadd:
1204   case Bytecodes::_fdiv:
1205   case Bytecodes::_fmul:
1206   case Bytecodes::_frem:
1207   case Bytecodes::_fsub:
1208     {
1209       pop_float();
1210       pop_float();
1211       push_float();
1212       break;
1213     }
1214   case Bytecodes::_faload:
1215     {
1216       pop_int();
1217       ciTypeArrayKlass* array_klass = pop_typeArray();
1218       // Put assert here.
1219       push_float();
1220       break;
1221     }
1222   case Bytecodes::_fastore:
1223     {
1224       pop_float();
1225       pop_int();
1226       ciTypeArrayKlass* array_klass = pop_typeArray();
1227       // Put assert here.
1228       break;
1229     }
1230   case Bytecodes::_fcmpg:
1231   case Bytecodes::_fcmpl:
1232     {
1233       pop_float();
1234       pop_float();
1235       push_int();
1236       break;
1237     }
1238   case Bytecodes::_fconst_0:
1239   case Bytecodes::_fconst_1:
1240   case Bytecodes::_fconst_2:
1241     {
1242       push_float();
1243       break;
1244     }
1245   case Bytecodes::_fload:   load_local_float(str->get_index());     break;
1246   case Bytecodes::_fload_0: load_local_float(0);                    break;
1247   case Bytecodes::_fload_1: load_local_float(1);                    break;
1248   case Bytecodes::_fload_2: load_local_float(2);                    break;
1249   case Bytecodes::_fload_3: load_local_float(3);                    break;
1250 
1251   case Bytecodes::_fneg:
1252     {
1253       pop_float();
1254       push_float();
1255       break;
1256     }
1257   case Bytecodes::_freturn:
1258     {
1259       pop_float();
1260       break;
1261     }
1262   case Bytecodes::_fstore:    store_local_float(str->get_index());   break;
1263   case Bytecodes::_fstore_0:  store_local_float(0);                  break;
1264   case Bytecodes::_fstore_1:  store_local_float(1);                  break;
1265   case Bytecodes::_fstore_2:  store_local_float(2);                  break;
1266   case Bytecodes::_fstore_3:  store_local_float(3);                  break;
1267 
1268   case Bytecodes::_getfield:  do_getfield(str);                      break;
1269   case Bytecodes::_getstatic: do_getstatic(str);                     break;
1270 
1271   case Bytecodes::_goto:
1272   case Bytecodes::_goto_w:
1273   case Bytecodes::_nop:
1274   case Bytecodes::_return:
1275     {
1276       // do nothing.
1277       break;
1278     }
1279   case Bytecodes::_i2b:
1280   case Bytecodes::_i2c:
1281   case Bytecodes::_i2s:
1282   case Bytecodes::_ineg:
1283     {
1284       pop_int();
1285       push_int();
1286       break;
1287     }
1288   case Bytecodes::_i2d:
1289     {
1290       pop_int();
1291       push_double();
1292       break;
1293     }
1294   case Bytecodes::_i2f:
1295     {
1296       pop_int();
1297       push_float();
1298       break;
1299     }
1300   case Bytecodes::_i2l:
1301     {
1302       pop_int();
1303       push_long();
1304       break;
1305     }
1306   case Bytecodes::_iadd:
1307   case Bytecodes::_iand:
1308   case Bytecodes::_idiv:
1309   case Bytecodes::_imul:
1310   case Bytecodes::_ior:
1311   case Bytecodes::_irem:
1312   case Bytecodes::_ishl:
1313   case Bytecodes::_ishr:
1314   case Bytecodes::_isub:
1315   case Bytecodes::_iushr:
1316   case Bytecodes::_ixor:
1317     {
1318       pop_int();
1319       pop_int();
1320       push_int();
1321       break;
1322     }
1323   case Bytecodes::_if_acmpeq:
1324   case Bytecodes::_if_acmpne:
1325     {
1326       pop_object();
1327       pop_object();
1328       break;
1329     }
1330   case Bytecodes::_if_icmpeq:
1331   case Bytecodes::_if_icmpge:
1332   case Bytecodes::_if_icmpgt:
1333   case Bytecodes::_if_icmple:
1334   case Bytecodes::_if_icmplt:
1335   case Bytecodes::_if_icmpne:
1336     {
1337       pop_int();
1338       pop_int();
1339       break;
1340     }
1341   case Bytecodes::_ifeq:
1342   case Bytecodes::_ifle:
1343   case Bytecodes::_iflt:
1344   case Bytecodes::_ifge:
1345   case Bytecodes::_ifgt:
1346   case Bytecodes::_ifne:
1347   case Bytecodes::_ireturn:
1348   case Bytecodes::_lookupswitch:
1349   case Bytecodes::_tableswitch:
1350     {
1351       pop_int();
1352       break;
1353     }
1354   case Bytecodes::_iinc:
1355     {
1356       int lnum = str->get_index();
1357       check_int(local(lnum));
1358       store_to_local(lnum);
1359       break;
1360     }
1361   case Bytecodes::_iload:   load_local_int(str->get_index()); break;
1362   case Bytecodes::_iload_0: load_local_int(0);                      break;
1363   case Bytecodes::_iload_1: load_local_int(1);                      break;
1364   case Bytecodes::_iload_2: load_local_int(2);                      break;
1365   case Bytecodes::_iload_3: load_local_int(3);                      break;
1366 
1367   case Bytecodes::_instanceof:
1368     {
1369       // Check for uncommon trap:
1370       do_checkcast(str);
1371       pop_object();
1372       push_int();
1373       break;
1374     }
1375   case Bytecodes::_invokeinterface: do_invoke(str, true);           break;
1376   case Bytecodes::_invokespecial:   do_invoke(str, true);           break;
1377   case Bytecodes::_invokestatic:    do_invoke(str, false);          break;
1378   case Bytecodes::_invokevirtual:   do_invoke(str, true);           break;
1379   case Bytecodes::_invokedynamic:   do_invoke(str, false);          break;
1380 
1381   case Bytecodes::_istore:   store_local_int(str->get_index());     break;
1382   case Bytecodes::_istore_0: store_local_int(0);                    break;
1383   case Bytecodes::_istore_1: store_local_int(1);                    break;
1384   case Bytecodes::_istore_2: store_local_int(2);                    break;
1385   case Bytecodes::_istore_3: store_local_int(3);                    break;
1386 
1387   case Bytecodes::_jsr:
1388   case Bytecodes::_jsr_w: do_jsr(str);                              break;
1389 
1390   case Bytecodes::_l2d:
1391     {
1392       pop_long();
1393       push_double();
1394       break;
1395     }
1396   case Bytecodes::_l2f:
1397     {
1398       pop_long();
1399       push_float();
1400       break;
1401     }
1402   case Bytecodes::_l2i:
1403     {
1404       pop_long();
1405       push_int();
1406       break;
1407     }
1408   case Bytecodes::_ladd:
1409   case Bytecodes::_land:
1410   case Bytecodes::_ldiv:
1411   case Bytecodes::_lmul:
1412   case Bytecodes::_lor:
1413   case Bytecodes::_lrem:
1414   case Bytecodes::_lsub:
1415   case Bytecodes::_lxor:
1416     {
1417       pop_long();
1418       pop_long();
1419       push_long();
1420       break;
1421     }
1422   case Bytecodes::_laload:
1423     {
1424       pop_int();
1425       ciTypeArrayKlass* array_klass = pop_typeArray();
1426       // Put assert here for right type?
1427       push_long();
1428       break;
1429     }
1430   case Bytecodes::_lastore:
1431     {
1432       pop_long();
1433       pop_int();
1434       pop_typeArray();
1435       // assert here?
1436       break;
1437     }
1438   case Bytecodes::_lcmp:
1439     {
1440       pop_long();
1441       pop_long();
1442       push_int();
1443       break;
1444     }
1445   case Bytecodes::_lconst_0:
1446   case Bytecodes::_lconst_1:
1447     {
1448       push_long();
1449       break;
1450     }
1451   case Bytecodes::_ldc:
1452   case Bytecodes::_ldc_w:
1453   case Bytecodes::_ldc2_w:
1454     {
1455       do_ldc(str);
1456       break;
1457     }
1458 
1459   case Bytecodes::_lload:   load_local_long(str->get_index());      break;
1460   case Bytecodes::_lload_0: load_local_long(0);                     break;
1461   case Bytecodes::_lload_1: load_local_long(1);                     break;
1462   case Bytecodes::_lload_2: load_local_long(2);                     break;
1463   case Bytecodes::_lload_3: load_local_long(3);                     break;
1464 
1465   case Bytecodes::_lneg:
1466     {
1467       pop_long();
1468       push_long();
1469       break;
1470     }
1471   case Bytecodes::_lreturn:
1472     {
1473       pop_long();
1474       break;
1475     }
1476   case Bytecodes::_lshl:
1477   case Bytecodes::_lshr:
1478   case Bytecodes::_lushr:
1479     {
1480       pop_int();
1481       pop_long();
1482       push_long();
1483       break;
1484     }
1485   case Bytecodes::_lstore:   store_local_long(str->get_index());    break;
1486   case Bytecodes::_lstore_0: store_local_long(0);                   break;
1487   case Bytecodes::_lstore_1: store_local_long(1);                   break;
1488   case Bytecodes::_lstore_2: store_local_long(2);                   break;
1489   case Bytecodes::_lstore_3: store_local_long(3);                   break;
1490 
1491   case Bytecodes::_multianewarray: do_multianewarray(str);          break;
1492 
1493   case Bytecodes::_new:      do_new(str);                           break;
1494 
1495   case Bytecodes::_defaultvalue: do_vdefault(str);                  break;
1496   case Bytecodes::_withfield: do_vwithfield(str);                   break;
1497 
1498   case Bytecodes::_newarray: do_newarray(str);                      break;
1499 
1500   case Bytecodes::_pop:
1501     {
1502       pop();
1503       break;
1504     }
1505   case Bytecodes::_pop2:
1506     {
1507       pop();
1508       pop();
1509       break;
1510     }
1511 
1512   case Bytecodes::_putfield:       do_putfield(str);                 break;
1513   case Bytecodes::_putstatic:      do_putstatic(str);                break;
1514 
1515   case Bytecodes::_ret: do_ret(str);                                 break;
1516 
1517   case Bytecodes::_swap:
1518     {
1519       ciType* value1 = pop_value();
1520       ciType* value2 = pop_value();
1521       push(value1);
1522       push(value2);
1523       break;
1524     }
1525 
1526   case Bytecodes::_wide:
1527   default:
1528     {
1529       // The iterator should skip this.
1530       ShouldNotReachHere();
1531       break;
1532     }
1533   }
1534 
1535   if (CITraceTypeFlow) {
1536     print_on(tty);
1537   }
1538 
1539   return (_trap_bci != -1);
1540 }
1541 
1542 #ifndef PRODUCT
1543 // ------------------------------------------------------------------
1544 // ciTypeFlow::StateVector::print_cell_on
1545 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1546   ciType* type = type_at(c);
1547   if (type == top_type()) {
1548     st->print("top");
1549   } else if (type == bottom_type()) {
1550     st->print("bottom");
1551   } else if (type == null_type()) {
1552     st->print("null");
1553   } else if (type == long2_type()) {
1554     st->print("long2");
1555   } else if (type == double2_type()) {
1556     st->print("double2");
1557   } else if (is_int(type)) {
1558     st->print("int");
1559   } else if (is_long(type)) {
1560     st->print("long");
1561   } else if (is_float(type)) {
1562     st->print("float");
1563   } else if (is_double(type)) {
1564     st->print("double");
1565   } else if (type->is_return_address()) {
1566     st->print("address(%d)", type->as_return_address()->bci());
1567   } else {
1568     if (type->is_klass()) {
1569       type->as_klass()->name()->print_symbol_on(st);
1570     } else {
1571       st->print("UNEXPECTED TYPE");
1572       type->print();
1573     }
1574   }
1575 }
1576 
1577 // ------------------------------------------------------------------
1578 // ciTypeFlow::StateVector::print_on
1579 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1580   int num_locals   = _outer->max_locals();
1581   int num_stack    = stack_size();
1582   int num_monitors = monitor_count();
1583   st->print_cr("  State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1584   if (num_stack >= 0) {
1585     int i;
1586     for (i = 0; i < num_locals; i++) {
1587       st->print("    local %2d : ", i);
1588       print_cell_on(st, local(i));
1589       st->cr();
1590     }
1591     for (i = 0; i < num_stack; i++) {
1592       st->print("    stack %2d : ", i);
1593       print_cell_on(st, stack(i));
1594       st->cr();
1595     }
1596   }
1597 }
1598 #endif
1599 
1600 
1601 // ------------------------------------------------------------------
1602 // ciTypeFlow::SuccIter::next
1603 //
1604 void ciTypeFlow::SuccIter::next() {
1605   int succ_ct = _pred->successors()->length();
1606   int next = _index + 1;
1607   if (next < succ_ct) {
1608     _index = next;
1609     _succ = _pred->successors()->at(next);
1610     return;
1611   }
1612   for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1613     // Do not compile any code for unloaded exception types.
1614     // Following compiler passes are responsible for doing this also.
1615     ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1616     if (exception_klass->is_loaded()) {
1617       _index = next;
1618       _succ = _pred->exceptions()->at(i);
1619       return;
1620     }
1621     next++;
1622   }
1623   _index = -1;
1624   _succ = NULL;
1625 }
1626 
1627 // ------------------------------------------------------------------
1628 // ciTypeFlow::SuccIter::set_succ
1629 //
1630 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1631   int succ_ct = _pred->successors()->length();
1632   if (_index < succ_ct) {
1633     _pred->successors()->at_put(_index, succ);
1634   } else {
1635     int idx = _index - succ_ct;
1636     _pred->exceptions()->at_put(idx, succ);
1637   }
1638 }
1639 
1640 // ciTypeFlow::Block
1641 //
1642 // A basic block.
1643 
1644 // ------------------------------------------------------------------
1645 // ciTypeFlow::Block::Block
1646 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1647                          ciBlock *ciblk,
1648                          ciTypeFlow::JsrSet* jsrs) {
1649   _ciblock = ciblk;
1650   _exceptions = NULL;
1651   _exc_klasses = NULL;
1652   _successors = NULL;
1653   _predecessors = new (outer->arena()) GrowableArray<Block*>(outer->arena(), 1, 0, NULL);
1654   _state = new (outer->arena()) StateVector(outer);
1655   JsrSet* new_jsrs =
1656     new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1657   jsrs->copy_into(new_jsrs);
1658   _jsrs = new_jsrs;
1659   _next = NULL;
1660   _on_work_list = false;
1661   _backedge_copy = false;
1662   _has_monitorenter = false;
1663   _trap_bci = -1;
1664   _trap_index = 0;
1665   df_init();
1666 
1667   if (CITraceTypeFlow) {
1668     tty->print_cr(">> Created new block");
1669     print_on(tty);
1670   }
1671 
1672   assert(this->outer() == outer, "outer link set up");
1673   assert(!outer->have_block_count(), "must not have mapped blocks yet");
1674 }
1675 
1676 // ------------------------------------------------------------------
1677 // ciTypeFlow::Block::df_init
1678 void ciTypeFlow::Block::df_init() {
1679   _pre_order = -1; assert(!has_pre_order(), "");
1680   _post_order = -1; assert(!has_post_order(), "");
1681   _loop = NULL;
1682   _irreducible_entry = false;
1683   _rpo_next = NULL;
1684 }
1685 
1686 // ------------------------------------------------------------------
1687 // ciTypeFlow::Block::successors
1688 //
1689 // Get the successors for this Block.
1690 GrowableArray<ciTypeFlow::Block*>*
1691 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1692                               ciTypeFlow::StateVector* state,
1693                               ciTypeFlow::JsrSet* jsrs) {
1694   if (_successors == NULL) {
1695     if (CITraceTypeFlow) {
1696       tty->print(">> Computing successors for block ");
1697       print_value_on(tty);
1698       tty->cr();
1699     }
1700 
1701     ciTypeFlow* analyzer = outer();
1702     Arena* arena = analyzer->arena();
1703     Block* block = NULL;
1704     bool has_successor = !has_trap() &&
1705                          (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1706     if (!has_successor) {
1707       _successors =
1708         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1709       // No successors
1710     } else if (control() == ciBlock::fall_through_bci) {
1711       assert(str->cur_bci() == limit(), "bad block end");
1712       // This block simply falls through to the next.
1713       _successors =
1714         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1715 
1716       Block* block = analyzer->block_at(limit(), _jsrs);
1717       assert(_successors->length() == FALL_THROUGH, "");
1718       _successors->append(block);
1719     } else {
1720       int current_bci = str->cur_bci();
1721       int next_bci = str->next_bci();
1722       int branch_bci = -1;
1723       Block* target = NULL;
1724       assert(str->next_bci() == limit(), "bad block end");
1725       // This block is not a simple fall-though.  Interpret
1726       // the current bytecode to find our successors.
1727       switch (str->cur_bc()) {
1728       case Bytecodes::_ifeq:         case Bytecodes::_ifne:
1729       case Bytecodes::_iflt:         case Bytecodes::_ifge:
1730       case Bytecodes::_ifgt:         case Bytecodes::_ifle:
1731       case Bytecodes::_if_icmpeq:    case Bytecodes::_if_icmpne:
1732       case Bytecodes::_if_icmplt:    case Bytecodes::_if_icmpge:
1733       case Bytecodes::_if_icmpgt:    case Bytecodes::_if_icmple:
1734       case Bytecodes::_if_acmpeq:    case Bytecodes::_if_acmpne:
1735       case Bytecodes::_ifnull:       case Bytecodes::_ifnonnull:
1736         // Our successors are the branch target and the next bci.
1737         branch_bci = str->get_dest();
1738         _successors =
1739           new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1740         assert(_successors->length() == IF_NOT_TAKEN, "");
1741         _successors->append(analyzer->block_at(next_bci, jsrs));
1742         assert(_successors->length() == IF_TAKEN, "");
1743         _successors->append(analyzer->block_at(branch_bci, jsrs));
1744         break;
1745 
1746       case Bytecodes::_goto:
1747         branch_bci = str->get_dest();
1748         _successors =
1749           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1750         assert(_successors->length() == GOTO_TARGET, "");
1751         _successors->append(analyzer->block_at(branch_bci, jsrs));
1752         break;
1753 
1754       case Bytecodes::_jsr:
1755         branch_bci = str->get_dest();
1756         _successors =
1757           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1758         assert(_successors->length() == GOTO_TARGET, "");
1759         _successors->append(analyzer->block_at(branch_bci, jsrs));
1760         break;
1761 
1762       case Bytecodes::_goto_w:
1763       case Bytecodes::_jsr_w:
1764         _successors =
1765           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1766         assert(_successors->length() == GOTO_TARGET, "");
1767         _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1768         break;
1769 
1770       case Bytecodes::_tableswitch:  {
1771         Bytecode_tableswitch tableswitch(str);
1772 
1773         int len = tableswitch.length();
1774         _successors =
1775           new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1776         int bci = current_bci + tableswitch.default_offset();
1777         Block* block = analyzer->block_at(bci, jsrs);
1778         assert(_successors->length() == SWITCH_DEFAULT, "");
1779         _successors->append(block);
1780         while (--len >= 0) {
1781           int bci = current_bci + tableswitch.dest_offset_at(len);
1782           block = analyzer->block_at(bci, jsrs);
1783           assert(_successors->length() >= SWITCH_CASES, "");
1784           _successors->append_if_missing(block);
1785         }
1786         break;
1787       }
1788 
1789       case Bytecodes::_lookupswitch: {
1790         Bytecode_lookupswitch lookupswitch(str);
1791 
1792         int npairs = lookupswitch.number_of_pairs();
1793         _successors =
1794           new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1795         int bci = current_bci + lookupswitch.default_offset();
1796         Block* block = analyzer->block_at(bci, jsrs);
1797         assert(_successors->length() == SWITCH_DEFAULT, "");
1798         _successors->append(block);
1799         while(--npairs >= 0) {
1800           LookupswitchPair pair = lookupswitch.pair_at(npairs);
1801           int bci = current_bci + pair.offset();
1802           Block* block = analyzer->block_at(bci, jsrs);
1803           assert(_successors->length() >= SWITCH_CASES, "");
1804           _successors->append_if_missing(block);
1805         }
1806         break;
1807       }
1808 
1809       case Bytecodes::_athrow:
1810       case Bytecodes::_ireturn:
1811       case Bytecodes::_lreturn:
1812       case Bytecodes::_freturn:
1813       case Bytecodes::_dreturn:
1814       case Bytecodes::_areturn:
1815       case Bytecodes::_return:
1816         _successors =
1817           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1818         // No successors
1819         break;
1820 
1821       case Bytecodes::_ret: {
1822         _successors =
1823           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1824 
1825         Cell local = state->local(str->get_index());
1826         ciType* return_address = state->type_at(local);
1827         assert(return_address->is_return_address(), "verify: wrong type");
1828         int bci = return_address->as_return_address()->bci();
1829         assert(_successors->length() == GOTO_TARGET, "");
1830         _successors->append(analyzer->block_at(bci, jsrs));
1831         break;
1832       }
1833 
1834       case Bytecodes::_wide:
1835       default:
1836         ShouldNotReachHere();
1837         break;
1838       }
1839     }
1840 
1841     // Set predecessor information
1842     for (int i = 0; i < _successors->length(); i++) {
1843       Block* block = _successors->at(i);
1844       block->predecessors()->append(this);
1845     }
1846   }
1847   return _successors;
1848 }
1849 
1850 // ------------------------------------------------------------------
1851 // ciTypeFlow::Block:compute_exceptions
1852 //
1853 // Compute the exceptional successors and types for this Block.
1854 void ciTypeFlow::Block::compute_exceptions() {
1855   assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1856 
1857   if (CITraceTypeFlow) {
1858     tty->print(">> Computing exceptions for block ");
1859     print_value_on(tty);
1860     tty->cr();
1861   }
1862 
1863   ciTypeFlow* analyzer = outer();
1864   Arena* arena = analyzer->arena();
1865 
1866   // Any bci in the block will do.
1867   ciExceptionHandlerStream str(analyzer->method(), start());
1868 
1869   // Allocate our growable arrays.
1870   int exc_count = str.count();
1871   _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1872   _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1873                                                              0, NULL);
1874 
1875   for ( ; !str.is_done(); str.next()) {
1876     ciExceptionHandler* handler = str.handler();
1877     int bci = handler->handler_bci();
1878     ciInstanceKlass* klass = NULL;
1879     if (bci == -1) {
1880       // There is no catch all.  It is possible to exit the method.
1881       break;
1882     }
1883     if (handler->is_catch_all()) {
1884       klass = analyzer->env()->Throwable_klass();
1885     } else {
1886       klass = handler->catch_klass();
1887     }
1888     Block* block = analyzer->block_at(bci, _jsrs);
1889     _exceptions->append(block);
1890     block->predecessors()->append(this);
1891     _exc_klasses->append(klass);
1892   }
1893 }
1894 
1895 // ------------------------------------------------------------------
1896 // ciTypeFlow::Block::set_backedge_copy
1897 // Use this only to make a pre-existing public block into a backedge copy.
1898 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1899   assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1900   _backedge_copy = z;
1901 }
1902 
1903 // ------------------------------------------------------------------
1904 // ciTypeFlow::Block::is_clonable_exit
1905 //
1906 // At most 2 normal successors, one of which continues looping,
1907 // and all exceptional successors must exit.
1908 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1909   int normal_cnt  = 0;
1910   int in_loop_cnt = 0;
1911   for (SuccIter iter(this); !iter.done(); iter.next()) {
1912     Block* succ = iter.succ();
1913     if (iter.is_normal_ctrl()) {
1914       if (++normal_cnt > 2) return false;
1915       if (lp->contains(succ->loop())) {
1916         if (++in_loop_cnt > 1) return false;
1917       }
1918     } else {
1919       if (lp->contains(succ->loop())) return false;
1920     }
1921   }
1922   return in_loop_cnt == 1;
1923 }
1924 
1925 // ------------------------------------------------------------------
1926 // ciTypeFlow::Block::looping_succ
1927 //
1928 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1929   assert(successors()->length() <= 2, "at most 2 normal successors");
1930   for (SuccIter iter(this); !iter.done(); iter.next()) {
1931     Block* succ = iter.succ();
1932     if (lp->contains(succ->loop())) {
1933       return succ;
1934     }
1935   }
1936   return NULL;
1937 }
1938 
1939 #ifndef PRODUCT
1940 // ------------------------------------------------------------------
1941 // ciTypeFlow::Block::print_value_on
1942 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1943   if (has_pre_order()) st->print("#%-2d ", pre_order());
1944   if (has_rpo())       st->print("rpo#%-2d ", rpo());
1945   st->print("[%d - %d)", start(), limit());
1946   if (is_loop_head()) st->print(" lphd");
1947   if (is_irreducible_entry()) st->print(" irred");
1948   if (_jsrs->size() > 0) { st->print("/");  _jsrs->print_on(st); }
1949   if (is_backedge_copy())  st->print("/backedge_copy");
1950 }
1951 
1952 // ------------------------------------------------------------------
1953 // ciTypeFlow::Block::print_on
1954 void ciTypeFlow::Block::print_on(outputStream* st) const {
1955   if ((Verbose || WizardMode) && (limit() >= 0)) {
1956     // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1957     outer()->method()->print_codes_on(start(), limit(), st);
1958   }
1959   st->print_cr("  ====================================================  ");
1960   st->print ("  ");
1961   print_value_on(st);
1962   st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1963   if (loop() && loop()->parent() != NULL) {
1964     st->print(" loops:");
1965     Loop* lp = loop();
1966     do {
1967       st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
1968       if (lp->is_irreducible()) st->print("(ir)");
1969       lp = lp->parent();
1970     } while (lp->parent() != NULL);
1971   }
1972   st->cr();
1973   _state->print_on(st);
1974   if (_successors == NULL) {
1975     st->print_cr("  No successor information");
1976   } else {
1977     int num_successors = _successors->length();
1978     st->print_cr("  Successors : %d", num_successors);
1979     for (int i = 0; i < num_successors; i++) {
1980       Block* successor = _successors->at(i);
1981       st->print("    ");
1982       successor->print_value_on(st);
1983       st->cr();
1984     }
1985   }
1986   if (_predecessors == NULL) {
1987     st->print_cr("  No predecessor information");
1988   } else {
1989     int num_predecessors = _predecessors->length();
1990     st->print_cr("  Predecessors : %d", num_predecessors);
1991     for (int i = 0; i < num_predecessors; i++) {
1992       Block* predecessor = _predecessors->at(i);
1993       st->print("    ");
1994       predecessor->print_value_on(st);
1995       st->cr();
1996     }
1997   }
1998   if (_exceptions == NULL) {
1999     st->print_cr("  No exception information");
2000   } else {
2001     int num_exceptions = _exceptions->length();
2002     st->print_cr("  Exceptions : %d", num_exceptions);
2003     for (int i = 0; i < num_exceptions; i++) {
2004       Block* exc_succ = _exceptions->at(i);
2005       ciInstanceKlass* exc_klass = _exc_klasses->at(i);
2006       st->print("    ");
2007       exc_succ->print_value_on(st);
2008       st->print(" -- ");
2009       exc_klass->name()->print_symbol_on(st);
2010       st->cr();
2011     }
2012   }
2013   if (has_trap()) {
2014     st->print_cr("  Traps on %d with trap index %d", trap_bci(), trap_index());
2015   }
2016   st->print_cr("  ====================================================  ");
2017 }
2018 #endif
2019 
2020 #ifndef PRODUCT
2021 // ------------------------------------------------------------------
2022 // ciTypeFlow::LocalSet::print_on
2023 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2024   st->print("{");
2025   for (int i = 0; i < max; i++) {
2026     if (test(i)) st->print(" %d", i);
2027   }
2028   if (limit > max) {
2029     st->print(" %d..%d ", max, limit);
2030   }
2031   st->print(" }");
2032 }
2033 #endif
2034 
2035 // ciTypeFlow
2036 //
2037 // This is a pass over the bytecodes which computes the following:
2038 //   basic block structure
2039 //   interpreter type-states (a la the verifier)
2040 
2041 // ------------------------------------------------------------------
2042 // ciTypeFlow::ciTypeFlow
2043 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2044   _env = env;
2045   _method = method;
2046   _methodBlocks = method->get_method_blocks();
2047   _max_locals = method->max_locals();
2048   _max_stack = method->max_stack();
2049   _code_size = method->code_size();
2050   _has_irreducible_entry = false;
2051   _osr_bci = osr_bci;
2052   _failure_reason = NULL;
2053   assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2054   _work_list = NULL;
2055 
2056   _ciblock_count = _methodBlocks->num_blocks();
2057   _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
2058   for (int i = 0; i < _ciblock_count; i++) {
2059     _idx_to_blocklist[i] = NULL;
2060   }
2061   _block_map = NULL;  // until all blocks are seen
2062   _jsr_count = 0;
2063   _jsr_records = NULL;
2064 }
2065 
2066 // ------------------------------------------------------------------
2067 // ciTypeFlow::work_list_next
2068 //
2069 // Get the next basic block from our work list.
2070 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2071   assert(!work_list_empty(), "work list must not be empty");
2072   Block* next_block = _work_list;
2073   _work_list = next_block->next();
2074   next_block->set_next(NULL);
2075   next_block->set_on_work_list(false);
2076   return next_block;
2077 }
2078 
2079 // ------------------------------------------------------------------
2080 // ciTypeFlow::add_to_work_list
2081 //
2082 // Add a basic block to our work list.
2083 // List is sorted by decreasing postorder sort (same as increasing RPO)
2084 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2085   assert(!block->is_on_work_list(), "must not already be on work list");
2086 
2087   if (CITraceTypeFlow) {
2088     tty->print(">> Adding block ");
2089     block->print_value_on(tty);
2090     tty->print_cr(" to the work list : ");
2091   }
2092 
2093   block->set_on_work_list(true);
2094 
2095   // decreasing post order sort
2096 
2097   Block* prev = NULL;
2098   Block* current = _work_list;
2099   int po = block->post_order();
2100   while (current != NULL) {
2101     if (!current->has_post_order() || po > current->post_order())
2102       break;
2103     prev = current;
2104     current = current->next();
2105   }
2106   if (prev == NULL) {
2107     block->set_next(_work_list);
2108     _work_list = block;
2109   } else {
2110     block->set_next(current);
2111     prev->set_next(block);
2112   }
2113 
2114   if (CITraceTypeFlow) {
2115     tty->cr();
2116   }
2117 }
2118 
2119 // ------------------------------------------------------------------
2120 // ciTypeFlow::block_at
2121 //
2122 // Return the block beginning at bci which has a JsrSet compatible
2123 // with jsrs.
2124 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2125   // First find the right ciBlock.
2126   if (CITraceTypeFlow) {
2127     tty->print(">> Requesting block for %d/", bci);
2128     jsrs->print_on(tty);
2129     tty->cr();
2130   }
2131 
2132   ciBlock* ciblk = _methodBlocks->block_containing(bci);
2133   assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2134   Block* block = get_block_for(ciblk->index(), jsrs, option);
2135 
2136   assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2137 
2138   if (CITraceTypeFlow) {
2139     if (block != NULL) {
2140       tty->print(">> Found block ");
2141       block->print_value_on(tty);
2142       tty->cr();
2143     } else {
2144       tty->print_cr(">> No such block.");
2145     }
2146   }
2147 
2148   return block;
2149 }
2150 
2151 // ------------------------------------------------------------------
2152 // ciTypeFlow::make_jsr_record
2153 //
2154 // Make a JsrRecord for a given (entry, return) pair, if such a record
2155 // does not already exist.
2156 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2157                                                    int return_address) {
2158   if (_jsr_records == NULL) {
2159     _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2160                                                            _jsr_count,
2161                                                            0,
2162                                                            NULL);
2163   }
2164   JsrRecord* record = NULL;
2165   int len = _jsr_records->length();
2166   for (int i = 0; i < len; i++) {
2167     JsrRecord* record = _jsr_records->at(i);
2168     if (record->entry_address() == entry_address &&
2169         record->return_address() == return_address) {
2170       return record;
2171     }
2172   }
2173 
2174   record = new (arena()) JsrRecord(entry_address, return_address);
2175   _jsr_records->append(record);
2176   return record;
2177 }
2178 
2179 // ------------------------------------------------------------------
2180 // ciTypeFlow::flow_exceptions
2181 //
2182 // Merge the current state into all exceptional successors at the
2183 // current point in the code.
2184 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2185                                  GrowableArray<ciInstanceKlass*>* exc_klasses,
2186                                  ciTypeFlow::StateVector* state) {
2187   int len = exceptions->length();
2188   assert(exc_klasses->length() == len, "must have same length");
2189   for (int i = 0; i < len; i++) {
2190     Block* block = exceptions->at(i);
2191     ciInstanceKlass* exception_klass = exc_klasses->at(i);
2192 
2193     if (!exception_klass->is_loaded()) {
2194       // Do not compile any code for unloaded exception types.
2195       // Following compiler passes are responsible for doing this also.
2196       continue;
2197     }
2198 
2199     if (block->meet_exception(exception_klass, state)) {
2200       // Block was modified and has PO.  Add it to the work list.
2201       if (block->has_post_order() &&
2202           !block->is_on_work_list()) {
2203         add_to_work_list(block);
2204       }
2205     }
2206   }
2207 }
2208 
2209 // ------------------------------------------------------------------
2210 // ciTypeFlow::flow_successors
2211 //
2212 // Merge the current state into all successors at the current point
2213 // in the code.
2214 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2215                                  ciTypeFlow::StateVector* state) {
2216   int len = successors->length();
2217   for (int i = 0; i < len; i++) {
2218     Block* block = successors->at(i);
2219     if (block->meet(state)) {
2220       // Block was modified and has PO.  Add it to the work list.
2221       if (block->has_post_order() &&
2222           !block->is_on_work_list()) {
2223         add_to_work_list(block);
2224       }
2225     }
2226   }
2227 }
2228 
2229 // ------------------------------------------------------------------
2230 // ciTypeFlow::can_trap
2231 //
2232 // Tells if a given instruction is able to generate an exception edge.
2233 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2234   // Cf. GenerateOopMap::do_exception_edge.
2235   if (!Bytecodes::can_trap(str.cur_bc()))  return false;
2236 
2237   switch (str.cur_bc()) {
2238     // %%% FIXME: ldc of Class can generate an exception
2239     case Bytecodes::_ldc:
2240     case Bytecodes::_ldc_w:
2241     case Bytecodes::_ldc2_w:
2242     case Bytecodes::_aload_0:
2243       // These bytecodes can trap for rewriting.  We need to assume that
2244       // they do not throw exceptions to make the monitor analysis work.
2245       return false;
2246 
2247     case Bytecodes::_ireturn:
2248     case Bytecodes::_lreturn:
2249     case Bytecodes::_freturn:
2250     case Bytecodes::_dreturn:
2251     case Bytecodes::_areturn:
2252     case Bytecodes::_return:
2253       // We can assume the monitor stack is empty in this analysis.
2254       return false;
2255 
2256     case Bytecodes::_monitorexit:
2257       // We can assume monitors are matched in this analysis.
2258       return false;
2259 
2260     default:
2261       return true;
2262   }
2263 }
2264 
2265 // ------------------------------------------------------------------
2266 // ciTypeFlow::clone_loop_heads
2267 //
2268 // Clone the loop heads
2269 bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2270   bool rslt = false;
2271   for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2272     lp = iter.current();
2273     Block* head = lp->head();
2274     if (lp == loop_tree_root() ||
2275         lp->is_irreducible() ||
2276         !head->is_clonable_exit(lp))
2277       continue;
2278 
2279     // Avoid BoxLock merge.
2280     if (EliminateNestedLocks && head->has_monitorenter())
2281       continue;
2282 
2283     // check not already cloned
2284     if (head->backedge_copy_count() != 0)
2285       continue;
2286 
2287     // Don't clone head of OSR loop to get correct types in start block.
2288     if (is_osr_flow() && head->start() == start_bci())
2289       continue;
2290 
2291     // check _no_ shared head below us
2292     Loop* ch;
2293     for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2294     if (ch != NULL)
2295       continue;
2296 
2297     // Clone head
2298     Block* new_head = head->looping_succ(lp);
2299     Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2300     // Update lp's info
2301     clone->set_loop(lp);
2302     lp->set_head(new_head);
2303     lp->set_tail(clone);
2304     // And move original head into outer loop
2305     head->set_loop(lp->parent());
2306 
2307     rslt = true;
2308   }
2309   return rslt;
2310 }
2311 
2312 // ------------------------------------------------------------------
2313 // ciTypeFlow::clone_loop_head
2314 //
2315 // Clone lp's head and replace tail's successors with clone.
2316 //
2317 //  |
2318 //  v
2319 // head <-> body
2320 //  |
2321 //  v
2322 // exit
2323 //
2324 // new_head
2325 //
2326 //  |
2327 //  v
2328 // head ----------\
2329 //  |             |
2330 //  |             v
2331 //  |  clone <-> body
2332 //  |    |
2333 //  | /--/
2334 //  | |
2335 //  v v
2336 // exit
2337 //
2338 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2339   Block* head = lp->head();
2340   Block* tail = lp->tail();
2341   if (CITraceTypeFlow) {
2342     tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2343     tty->print("  for predecessor ");                tail->print_value_on(tty);
2344     tty->cr();
2345   }
2346   Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2347   assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2348 
2349   assert(!clone->has_pre_order(), "just created");
2350   clone->set_next_pre_order();
2351 
2352   // Insert clone after (orig) tail in reverse post order
2353   clone->set_rpo_next(tail->rpo_next());
2354   tail->set_rpo_next(clone);
2355 
2356   // tail->head becomes tail->clone
2357   for (SuccIter iter(tail); !iter.done(); iter.next()) {
2358     if (iter.succ() == head) {
2359       iter.set_succ(clone);
2360       // Update predecessor information
2361       head->predecessors()->remove(tail);
2362       clone->predecessors()->append(tail);
2363     }
2364   }
2365   flow_block(tail, temp_vector, temp_set);
2366   if (head == tail) {
2367     // For self-loops, clone->head becomes clone->clone
2368     flow_block(clone, temp_vector, temp_set);
2369     for (SuccIter iter(clone); !iter.done(); iter.next()) {
2370       if (iter.succ() == head) {
2371         iter.set_succ(clone);
2372         // Update predecessor information
2373         head->predecessors()->remove(clone);
2374         clone->predecessors()->append(clone);
2375         break;
2376       }
2377     }
2378   }
2379   flow_block(clone, temp_vector, temp_set);
2380 
2381   return clone;
2382 }
2383 
2384 // ------------------------------------------------------------------
2385 // ciTypeFlow::flow_block
2386 //
2387 // Interpret the effects of the bytecodes on the incoming state
2388 // vector of a basic block.  Push the changed state to succeeding
2389 // basic blocks.
2390 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2391                             ciTypeFlow::StateVector* state,
2392                             ciTypeFlow::JsrSet* jsrs) {
2393   if (CITraceTypeFlow) {
2394     tty->print("\n>> ANALYZING BLOCK : ");
2395     tty->cr();
2396     block->print_on(tty);
2397   }
2398   assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2399 
2400   int start = block->start();
2401   int limit = block->limit();
2402   int control = block->control();
2403   if (control != ciBlock::fall_through_bci) {
2404     limit = control;
2405   }
2406 
2407   // Grab the state from the current block.
2408   block->copy_state_into(state);
2409   state->def_locals()->clear();
2410 
2411   GrowableArray<Block*>*           exceptions = block->exceptions();
2412   GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2413   bool has_exceptions = exceptions->length() > 0;
2414 
2415   bool exceptions_used = false;
2416 
2417   ciBytecodeStream str(method());
2418   str.reset_to_bci(start);
2419   Bytecodes::Code code;
2420   while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2421          str.cur_bci() < limit) {
2422     // Check for exceptional control flow from this point.
2423     if (has_exceptions && can_trap(str)) {
2424       flow_exceptions(exceptions, exc_klasses, state);
2425       exceptions_used = true;
2426     }
2427     // Apply the effects of the current bytecode to our state.
2428     bool res = state->apply_one_bytecode(&str);
2429 
2430     // Watch for bailouts.
2431     if (failing())  return;
2432 
2433     if (str.cur_bc() == Bytecodes::_monitorenter) {
2434       block->set_has_monitorenter();
2435     }
2436 
2437     if (res) {
2438 
2439       // We have encountered a trap.  Record it in this block.
2440       block->set_trap(state->trap_bci(), state->trap_index());
2441 
2442       if (CITraceTypeFlow) {
2443         tty->print_cr(">> Found trap");
2444         block->print_on(tty);
2445       }
2446 
2447       // Save set of locals defined in this block
2448       block->def_locals()->add(state->def_locals());
2449 
2450       // Record (no) successors.
2451       block->successors(&str, state, jsrs);
2452 
2453       assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2454 
2455       // Discontinue interpretation of this Block.
2456       return;
2457     }
2458   }
2459 
2460   GrowableArray<Block*>* successors = NULL;
2461   if (control != ciBlock::fall_through_bci) {
2462     // Check for exceptional control flow from this point.
2463     if (has_exceptions && can_trap(str)) {
2464       flow_exceptions(exceptions, exc_klasses, state);
2465       exceptions_used = true;
2466     }
2467 
2468     // Fix the JsrSet to reflect effect of the bytecode.
2469     block->copy_jsrs_into(jsrs);
2470     jsrs->apply_control(this, &str, state);
2471 
2472     // Find successor edges based on old state and new JsrSet.
2473     successors = block->successors(&str, state, jsrs);
2474 
2475     // Apply the control changes to the state.
2476     state->apply_one_bytecode(&str);
2477   } else {
2478     // Fall through control
2479     successors = block->successors(&str, NULL, NULL);
2480   }
2481 
2482   // Save set of locals defined in this block
2483   block->def_locals()->add(state->def_locals());
2484 
2485   // Remove untaken exception paths
2486   if (!exceptions_used)
2487     exceptions->clear();
2488 
2489   // Pass our state to successors.
2490   flow_successors(successors, state);
2491 }
2492 
2493 // ------------------------------------------------------------------
2494 // ciTypeFlow::PostOrderLoops::next
2495 //
2496 // Advance to next loop tree using a postorder, left-to-right traversal.
2497 void ciTypeFlow::PostorderLoops::next() {
2498   assert(!done(), "must not be done.");
2499   if (_current->sibling() != NULL) {
2500     _current = _current->sibling();
2501     while (_current->child() != NULL) {
2502       _current = _current->child();
2503     }
2504   } else {
2505     _current = _current->parent();
2506   }
2507 }
2508 
2509 // ------------------------------------------------------------------
2510 // ciTypeFlow::PreOrderLoops::next
2511 //
2512 // Advance to next loop tree using a preorder, left-to-right traversal.
2513 void ciTypeFlow::PreorderLoops::next() {
2514   assert(!done(), "must not be done.");
2515   if (_current->child() != NULL) {
2516     _current = _current->child();
2517   } else if (_current->sibling() != NULL) {
2518     _current = _current->sibling();
2519   } else {
2520     while (_current != _root && _current->sibling() == NULL) {
2521       _current = _current->parent();
2522     }
2523     if (_current == _root) {
2524       _current = NULL;
2525       assert(done(), "must be done.");
2526     } else {
2527       assert(_current->sibling() != NULL, "must be more to do");
2528       _current = _current->sibling();
2529     }
2530   }
2531 }
2532 
2533 // ------------------------------------------------------------------
2534 // ciTypeFlow::Loop::sorted_merge
2535 //
2536 // Merge the branch lp into this branch, sorting on the loop head
2537 // pre_orders. Returns the leaf of the merged branch.
2538 // Child and sibling pointers will be setup later.
2539 // Sort is (looking from leaf towards the root)
2540 //  descending on primary key: loop head's pre_order, and
2541 //  ascending  on secondary key: loop tail's pre_order.
2542 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2543   Loop* leaf = this;
2544   Loop* prev = NULL;
2545   Loop* current = leaf;
2546   while (lp != NULL) {
2547     int lp_pre_order = lp->head()->pre_order();
2548     // Find insertion point for "lp"
2549     while (current != NULL) {
2550       if (current == lp)
2551         return leaf; // Already in list
2552       if (current->head()->pre_order() < lp_pre_order)
2553         break;
2554       if (current->head()->pre_order() == lp_pre_order &&
2555           current->tail()->pre_order() > lp->tail()->pre_order()) {
2556         break;
2557       }
2558       prev = current;
2559       current = current->parent();
2560     }
2561     Loop* next_lp = lp->parent(); // Save future list of items to insert
2562     // Insert lp before current
2563     lp->set_parent(current);
2564     if (prev != NULL) {
2565       prev->set_parent(lp);
2566     } else {
2567       leaf = lp;
2568     }
2569     prev = lp;     // Inserted item is new prev[ious]
2570     lp = next_lp;  // Next item to insert
2571   }
2572   return leaf;
2573 }
2574 
2575 // ------------------------------------------------------------------
2576 // ciTypeFlow::build_loop_tree
2577 //
2578 // Incrementally build loop tree.
2579 void ciTypeFlow::build_loop_tree(Block* blk) {
2580   assert(!blk->is_post_visited(), "precondition");
2581   Loop* innermost = NULL; // merge of loop tree branches over all successors
2582 
2583   for (SuccIter iter(blk); !iter.done(); iter.next()) {
2584     Loop*  lp   = NULL;
2585     Block* succ = iter.succ();
2586     if (!succ->is_post_visited()) {
2587       // Found backedge since predecessor post visited, but successor is not
2588       assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2589 
2590       // Create a LoopNode to mark this loop.
2591       lp = new (arena()) Loop(succ, blk);
2592       if (succ->loop() == NULL)
2593         succ->set_loop(lp);
2594       // succ->loop will be updated to innermost loop on a later call, when blk==succ
2595 
2596     } else {  // Nested loop
2597       lp = succ->loop();
2598 
2599       // If succ is loop head, find outer loop.
2600       while (lp != NULL && lp->head() == succ) {
2601         lp = lp->parent();
2602       }
2603       if (lp == NULL) {
2604         // Infinite loop, it's parent is the root
2605         lp = loop_tree_root();
2606       }
2607     }
2608 
2609     // Check for irreducible loop.
2610     // Successor has already been visited. If the successor's loop head
2611     // has already been post-visited, then this is another entry into the loop.
2612     while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2613       _has_irreducible_entry = true;
2614       lp->set_irreducible(succ);
2615       if (!succ->is_on_work_list()) {
2616         // Assume irreducible entries need more data flow
2617         add_to_work_list(succ);
2618       }
2619       Loop* plp = lp->parent();
2620       if (plp == NULL) {
2621         // This only happens for some irreducible cases.  The parent
2622         // will be updated during a later pass.
2623         break;
2624       }
2625       lp = plp;
2626     }
2627 
2628     // Merge loop tree branch for all successors.
2629     innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2630 
2631   } // end loop
2632 
2633   if (innermost == NULL) {
2634     assert(blk->successors()->length() == 0, "CFG exit");
2635     blk->set_loop(loop_tree_root());
2636   } else if (innermost->head() == blk) {
2637     // If loop header, complete the tree pointers
2638     if (blk->loop() != innermost) {
2639 #ifdef ASSERT
2640       assert(blk->loop()->head() == innermost->head(), "same head");
2641       Loop* dl;
2642       for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2643       assert(dl == blk->loop(), "blk->loop() already in innermost list");
2644 #endif
2645       blk->set_loop(innermost);
2646     }
2647     innermost->def_locals()->add(blk->def_locals());
2648     Loop* l = innermost;
2649     Loop* p = l->parent();
2650     while (p && l->head() == blk) {
2651       l->set_sibling(p->child());  // Put self on parents 'next child'
2652       p->set_child(l);             // Make self the first child of parent
2653       p->def_locals()->add(l->def_locals());
2654       l = p;                       // Walk up the parent chain
2655       p = l->parent();
2656     }
2657   } else {
2658     blk->set_loop(innermost);
2659     innermost->def_locals()->add(blk->def_locals());
2660   }
2661 }
2662 
2663 // ------------------------------------------------------------------
2664 // ciTypeFlow::Loop::contains
2665 //
2666 // Returns true if lp is nested loop.
2667 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2668   assert(lp != NULL, "");
2669   if (this == lp || head() == lp->head()) return true;
2670   int depth1 = depth();
2671   int depth2 = lp->depth();
2672   if (depth1 > depth2)
2673     return false;
2674   while (depth1 < depth2) {
2675     depth2--;
2676     lp = lp->parent();
2677   }
2678   return this == lp;
2679 }
2680 
2681 // ------------------------------------------------------------------
2682 // ciTypeFlow::Loop::depth
2683 //
2684 // Loop depth
2685 int ciTypeFlow::Loop::depth() const {
2686   int dp = 0;
2687   for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2688     dp++;
2689   return dp;
2690 }
2691 
2692 #ifndef PRODUCT
2693 // ------------------------------------------------------------------
2694 // ciTypeFlow::Loop::print
2695 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2696   for (int i = 0; i < indent; i++) st->print(" ");
2697   st->print("%d<-%d %s",
2698             is_root() ? 0 : this->head()->pre_order(),
2699             is_root() ? 0 : this->tail()->pre_order(),
2700             is_irreducible()?" irr":"");
2701   st->print(" defs: ");
2702   def_locals()->print_on(st, _head->outer()->method()->max_locals());
2703   st->cr();
2704   for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2705     ch->print(st, indent+2);
2706 }
2707 #endif
2708 
2709 // ------------------------------------------------------------------
2710 // ciTypeFlow::df_flow_types
2711 //
2712 // Perform the depth first type flow analysis. Helper for flow_types.
2713 void ciTypeFlow::df_flow_types(Block* start,
2714                                bool do_flow,
2715                                StateVector* temp_vector,
2716                                JsrSet* temp_set) {
2717   int dft_len = 100;
2718   GrowableArray<Block*> stk(dft_len);
2719 
2720   ciBlock* dummy = _methodBlocks->make_dummy_block();
2721   JsrSet* root_set = new JsrSet(NULL, 0);
2722   Block* root_head = new (arena()) Block(this, dummy, root_set);
2723   Block* root_tail = new (arena()) Block(this, dummy, root_set);
2724   root_head->set_pre_order(0);
2725   root_head->set_post_order(0);
2726   root_tail->set_pre_order(max_jint);
2727   root_tail->set_post_order(max_jint);
2728   set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2729 
2730   stk.push(start);
2731 
2732   _next_pre_order = 0;  // initialize pre_order counter
2733   _rpo_list = NULL;
2734   int next_po = 0;      // initialize post_order counter
2735 
2736   // Compute RPO and the control flow graph
2737   int size;
2738   while ((size = stk.length()) > 0) {
2739     Block* blk = stk.top(); // Leave node on stack
2740     if (!blk->is_visited()) {
2741       // forward arc in graph
2742       assert (!blk->has_pre_order(), "");
2743       blk->set_next_pre_order();
2744 
2745       if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2746         // Too many basic blocks.  Bail out.
2747         // This can happen when try/finally constructs are nested to depth N,
2748         // and there is O(2**N) cloning of jsr bodies.  See bug 4697245!
2749         // "MaxNodeLimit / 2" is used because probably the parser will
2750         // generate at least twice that many nodes and bail out.
2751         record_failure("too many basic blocks");
2752         return;
2753       }
2754       if (do_flow) {
2755         flow_block(blk, temp_vector, temp_set);
2756         if (failing()) return; // Watch for bailouts.
2757       }
2758     } else if (!blk->is_post_visited()) {
2759       // cross or back arc
2760       for (SuccIter iter(blk); !iter.done(); iter.next()) {
2761         Block* succ = iter.succ();
2762         if (!succ->is_visited()) {
2763           stk.push(succ);
2764         }
2765       }
2766       if (stk.length() == size) {
2767         // There were no additional children, post visit node now
2768         stk.pop(); // Remove node from stack
2769 
2770         build_loop_tree(blk);
2771         blk->set_post_order(next_po++);   // Assign post order
2772         prepend_to_rpo_list(blk);
2773         assert(blk->is_post_visited(), "");
2774 
2775         if (blk->is_loop_head() && !blk->is_on_work_list()) {
2776           // Assume loop heads need more data flow
2777           add_to_work_list(blk);
2778         }
2779       }
2780     } else {
2781       stk.pop(); // Remove post-visited node from stack
2782     }
2783   }
2784 }
2785 
2786 // ------------------------------------------------------------------
2787 // ciTypeFlow::flow_types
2788 //
2789 // Perform the type flow analysis, creating and cloning Blocks as
2790 // necessary.
2791 void ciTypeFlow::flow_types() {
2792   ResourceMark rm;
2793   StateVector* temp_vector = new StateVector(this);
2794   JsrSet* temp_set = new JsrSet(NULL, 16);
2795 
2796   // Create the method entry block.
2797   Block* start = block_at(start_bci(), temp_set);
2798 
2799   // Load the initial state into it.
2800   const StateVector* start_state = get_start_state();
2801   if (failing())  return;
2802   start->meet(start_state);
2803 
2804   // Depth first visit
2805   df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2806 
2807   if (failing())  return;
2808   assert(_rpo_list == start, "must be start");
2809 
2810   // Any loops found?
2811   if (loop_tree_root()->child() != NULL &&
2812       env()->comp_level() >= CompLevel_full_optimization) {
2813       // Loop optimizations are not performed on Tier1 compiles.
2814 
2815     bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2816 
2817     // If some loop heads were cloned, recompute postorder and loop tree
2818     if (changed) {
2819       loop_tree_root()->set_child(NULL);
2820       for (Block* blk = _rpo_list; blk != NULL;) {
2821         Block* next = blk->rpo_next();
2822         blk->df_init();
2823         blk = next;
2824       }
2825       df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2826     }
2827   }
2828 
2829   if (CITraceTypeFlow) {
2830     tty->print_cr("\nLoop tree");
2831     loop_tree_root()->print();
2832   }
2833 
2834   // Continue flow analysis until fixed point reached
2835 
2836   debug_only(int max_block = _next_pre_order;)
2837 
2838   while (!work_list_empty()) {
2839     Block* blk = work_list_next();
2840     assert (blk->has_post_order(), "post order assigned above");
2841 
2842     flow_block(blk, temp_vector, temp_set);
2843 
2844     assert (max_block == _next_pre_order, "no new blocks");
2845     assert (!failing(), "no more bailouts");
2846   }
2847 }
2848 
2849 // ------------------------------------------------------------------
2850 // ciTypeFlow::map_blocks
2851 //
2852 // Create the block map, which indexes blocks in reverse post-order.
2853 void ciTypeFlow::map_blocks() {
2854   assert(_block_map == NULL, "single initialization");
2855   int block_ct = _next_pre_order;
2856   _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2857   assert(block_ct == block_count(), "");
2858 
2859   Block* blk = _rpo_list;
2860   for (int m = 0; m < block_ct; m++) {
2861     int rpo = blk->rpo();
2862     assert(rpo == m, "should be sequential");
2863     _block_map[rpo] = blk;
2864     blk = blk->rpo_next();
2865   }
2866   assert(blk == NULL, "should be done");
2867 
2868   for (int j = 0; j < block_ct; j++) {
2869     assert(_block_map[j] != NULL, "must not drop any blocks");
2870     Block* block = _block_map[j];
2871     // Remove dead blocks from successor lists:
2872     for (int e = 0; e <= 1; e++) {
2873       GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2874       for (int k = 0; k < l->length(); k++) {
2875         Block* s = l->at(k);
2876         if (!s->has_post_order()) {
2877           if (CITraceTypeFlow) {
2878             tty->print("Removing dead %s successor of #%d: ", (e? "exceptional":  "normal"), block->pre_order());
2879             s->print_value_on(tty);
2880             tty->cr();
2881           }
2882           l->remove(s);
2883           --k;
2884         }
2885       }
2886     }
2887   }
2888 }
2889 
2890 // ------------------------------------------------------------------
2891 // ciTypeFlow::get_block_for
2892 //
2893 // Find a block with this ciBlock which has a compatible JsrSet.
2894 // If no such block exists, create it, unless the option is no_create.
2895 // If the option is create_backedge_copy, always create a fresh backedge copy.
2896 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2897   Arena* a = arena();
2898   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2899   if (blocks == NULL) {
2900     // Query only?
2901     if (option == no_create)  return NULL;
2902 
2903     // Allocate the growable array.
2904     blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2905     _idx_to_blocklist[ciBlockIndex] = blocks;
2906   }
2907 
2908   if (option != create_backedge_copy) {
2909     int len = blocks->length();
2910     for (int i = 0; i < len; i++) {
2911       Block* block = blocks->at(i);
2912       if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2913         return block;
2914       }
2915     }
2916   }
2917 
2918   // Query only?
2919   if (option == no_create)  return NULL;
2920 
2921   // We did not find a compatible block.  Create one.
2922   Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2923   if (option == create_backedge_copy)  new_block->set_backedge_copy(true);
2924   blocks->append(new_block);
2925   return new_block;
2926 }
2927 
2928 // ------------------------------------------------------------------
2929 // ciTypeFlow::backedge_copy_count
2930 //
2931 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2932   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2933 
2934   if (blocks == NULL) {
2935     return 0;
2936   }
2937 
2938   int count = 0;
2939   int len = blocks->length();
2940   for (int i = 0; i < len; i++) {
2941     Block* block = blocks->at(i);
2942     if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2943       count++;
2944     }
2945   }
2946 
2947   return count;
2948 }
2949 
2950 // ------------------------------------------------------------------
2951 // ciTypeFlow::do_flow
2952 //
2953 // Perform type inference flow analysis.
2954 void ciTypeFlow::do_flow() {
2955   if (CITraceTypeFlow) {
2956     tty->print_cr("\nPerforming flow analysis on method");
2957     method()->print();
2958     if (is_osr_flow())  tty->print(" at OSR bci %d", start_bci());
2959     tty->cr();
2960     method()->print_codes();
2961   }
2962   if (CITraceTypeFlow) {
2963     tty->print_cr("Initial CI Blocks");
2964     print_on(tty);
2965   }
2966   flow_types();
2967   // Watch for bailouts.
2968   if (failing()) {
2969     return;
2970   }
2971 
2972   map_blocks();
2973 
2974   if (CIPrintTypeFlow || CITraceTypeFlow) {
2975     rpo_print_on(tty);
2976   }
2977 }
2978 
2979 // ------------------------------------------------------------------
2980 // ciTypeFlow::is_dominated_by
2981 //
2982 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
2983 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
2984   assert(!method()->has_jsrs(), "jsrs are not supported");
2985 
2986   ResourceMark rm;
2987   JsrSet* jsrs = new ciTypeFlow::JsrSet(NULL);
2988   int        index = _methodBlocks->block_containing(bci)->index();
2989   int    dom_index = _methodBlocks->block_containing(dom_bci)->index();
2990   Block*     block = get_block_for(index, jsrs, ciTypeFlow::no_create);
2991   Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
2992 
2993   // Start block dominates all other blocks
2994   if (start_block()->rpo() == dom_block->rpo()) {
2995     return true;
2996   }
2997 
2998   // Dominated[i] is true if block i is dominated by dom_block
2999   int num_blocks = block_count();
3000   bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
3001   for (int i = 0; i < num_blocks; ++i) {
3002     dominated[i] = true;
3003   }
3004   dominated[start_block()->rpo()] = false;
3005 
3006   // Iterative dominator algorithm
3007   bool changed = true;
3008   while (changed) {
3009     changed = false;
3010     // Use reverse postorder iteration
3011     for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3012       if (blk->is_start()) {
3013         // Ignore start block
3014         continue;
3015       }
3016       // The block is dominated if it is the dominating block
3017       // itself or if all predecessors are dominated.
3018       int index = blk->rpo();
3019       bool dom = (index == dom_block->rpo());
3020       if (!dom) {
3021         // Check if all predecessors are dominated
3022         dom = true;
3023         for (int i = 0; i < blk->predecessors()->length(); ++i) {
3024           Block* pred = blk->predecessors()->at(i);
3025           if (!dominated[pred->rpo()]) {
3026             dom = false;
3027             break;
3028           }
3029         }
3030       }
3031       // Update dominator information
3032       if (dominated[index] != dom) {
3033         changed = true;
3034         dominated[index] = dom;
3035       }
3036     }
3037   }
3038   // block dominated by dom_block?
3039   return dominated[block->rpo()];
3040 }
3041 
3042 // ------------------------------------------------------------------
3043 // ciTypeFlow::record_failure()
3044 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3045 // This is required because there is not a 1-1 relation between the ciEnv and
3046 // the TypeFlow passes within a compilation task.  For example, if the compiler
3047 // is considering inlining a method, it will request a TypeFlow.  If that fails,
3048 // the compilation as a whole may continue without the inlining.  Some TypeFlow
3049 // requests are not optional; if they fail the requestor is responsible for
3050 // copying the failure reason up to the ciEnv.  (See Parse::Parse.)
3051 void ciTypeFlow::record_failure(const char* reason) {
3052   if (env()->log() != NULL) {
3053     env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3054   }
3055   if (_failure_reason == NULL) {
3056     // Record the first failure reason.
3057     _failure_reason = reason;
3058   }
3059 }
3060 
3061 #ifndef PRODUCT
3062 // ------------------------------------------------------------------
3063 // ciTypeFlow::print_on
3064 void ciTypeFlow::print_on(outputStream* st) const {
3065   // Walk through CI blocks
3066   st->print_cr("********************************************************");
3067   st->print   ("TypeFlow for ");
3068   method()->name()->print_symbol_on(st);
3069   int limit_bci = code_size();
3070   st->print_cr("  %d bytes", limit_bci);
3071   ciMethodBlocks  *mblks = _methodBlocks;
3072   ciBlock* current = NULL;
3073   for (int bci = 0; bci < limit_bci; bci++) {
3074     ciBlock* blk = mblks->block_containing(bci);
3075     if (blk != NULL && blk != current) {
3076       current = blk;
3077       current->print_on(st);
3078 
3079       GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3080       int num_blocks = (blocks == NULL) ? 0 : blocks->length();
3081 
3082       if (num_blocks == 0) {
3083         st->print_cr("  No Blocks");
3084       } else {
3085         for (int i = 0; i < num_blocks; i++) {
3086           Block* block = blocks->at(i);
3087           block->print_on(st);
3088         }
3089       }
3090       st->print_cr("--------------------------------------------------------");
3091       st->cr();
3092     }
3093   }
3094   st->print_cr("********************************************************");
3095   st->cr();
3096 }
3097 
3098 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3099   st->print_cr("********************************************************");
3100   st->print   ("TypeFlow for ");
3101   method()->name()->print_symbol_on(st);
3102   int limit_bci = code_size();
3103   st->print_cr("  %d bytes", limit_bci);
3104   for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3105     blk->print_on(st);
3106     st->print_cr("--------------------------------------------------------");
3107     st->cr();
3108   }
3109   st->print_cr("********************************************************");
3110   st->cr();
3111 }
3112 #endif