1 /*
   2  * Copyright (c) 2000, 2015, 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 "compiler/compileLog.hpp"
  35 #include "interpreter/bytecode.hpp"
  36 #include "interpreter/bytecodes.hpp"
  37 #include "memory/allocation.inline.hpp"
  38 #include "oops/oop.inline.hpp"
  39 #include "opto/compile.hpp"
  40 #include "opto/node.hpp"
  41 #include "runtime/deoptimization.hpp"
  42 #include "utilities/growableArray.hpp"
  43 
  44 // ciTypeFlow::JsrSet
  45 //
  46 // A JsrSet represents some set of JsrRecords.  This class
  47 // is used to record a set of all jsr routines which we permit
  48 // execution to return (ret) from.
  49 //
  50 // During abstract interpretation, JsrSets are used to determine
  51 // whether two paths which reach a given block are unique, and
  52 // should be cloned apart, or are compatible, and should merge
  53 // together.
  54 
  55 // ------------------------------------------------------------------
  56 // ciTypeFlow::JsrSet::JsrSet
  57 ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) {
  58   if (arena != NULL) {
  59     // Allocate growable array in Arena.
  60     _set = new (arena) GrowableArray<JsrRecord*>(arena, default_len, 0, NULL);
  61   } else {
  62     // Allocate growable array in current ResourceArea.
  63     _set = new GrowableArray<JsrRecord*>(4, 0, NULL, false);
  64   }
  65 }
  66 
  67 // ------------------------------------------------------------------
  68 // ciTypeFlow::JsrSet::copy_into
  69 void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
  70   int len = size();
  71   jsrs->_set->clear();
  72   for (int i = 0; i < len; i++) {
  73     jsrs->_set->append(_set->at(i));
  74   }
  75 }
  76 
  77 // ------------------------------------------------------------------
  78 // ciTypeFlow::JsrSet::is_compatible_with
  79 //
  80 // !!!! MISGIVINGS ABOUT THIS... disregard
  81 //
  82 // Is this JsrSet compatible with some other JsrSet?
  83 //
  84 // In set-theoretic terms, a JsrSet can be viewed as a partial function
  85 // from entry addresses to return addresses.  Two JsrSets A and B are
  86 // compatible iff
  87 //
  88 //   For any x,
  89 //   A(x) defined and B(x) defined implies A(x) == B(x)
  90 //
  91 // Less formally, two JsrSets are compatible when they have identical
  92 // return addresses for any entry addresses they share in common.
  93 bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
  94   // Walk through both sets in parallel.  If the same entry address
  95   // appears in both sets, then the return address must match for
  96   // the sets to be compatible.
  97   int size1 = size();
  98   int size2 = other->size();
  99 
 100   // Special case.  If nothing is on the jsr stack, then there can
 101   // be no ret.
 102   if (size2 == 0) {
 103     return true;
 104   } else if (size1 != size2) {
 105     return false;
 106   } else {
 107     for (int i = 0; i < size1; i++) {
 108       JsrRecord* record1 = record_at(i);
 109       JsrRecord* record2 = other->record_at(i);
 110       if (record1->entry_address() != record2->entry_address() ||
 111           record1->return_address() != record2->return_address()) {
 112         return false;
 113       }
 114     }
 115     return true;
 116   }
 117 
 118 #if 0
 119   int pos1 = 0;
 120   int pos2 = 0;
 121   int size1 = size();
 122   int size2 = other->size();
 123   while (pos1 < size1 && pos2 < size2) {
 124     JsrRecord* record1 = record_at(pos1);
 125     JsrRecord* record2 = other->record_at(pos2);
 126     int entry1 = record1->entry_address();
 127     int entry2 = record2->entry_address();
 128     if (entry1 < entry2) {
 129       pos1++;
 130     } else if (entry1 > entry2) {
 131       pos2++;
 132     } else {
 133       if (record1->return_address() == record2->return_address()) {
 134         pos1++;
 135         pos2++;
 136       } else {
 137         // These two JsrSets are incompatible.
 138         return false;
 139       }
 140     }
 141   }
 142   // The two JsrSets agree.
 143   return true;
 144 #endif
 145 }
 146 
 147 // ------------------------------------------------------------------
 148 // ciTypeFlow::JsrSet::insert_jsr_record
 149 //
 150 // Insert the given JsrRecord into the JsrSet, maintaining the order
 151 // of the set and replacing any element with the same entry address.
 152 void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
 153   int len = size();
 154   int entry = record->entry_address();
 155   int pos = 0;
 156   for ( ; pos < len; pos++) {
 157     JsrRecord* current = record_at(pos);
 158     if (entry == current->entry_address()) {
 159       // Stomp over this entry.
 160       _set->at_put(pos, record);
 161       assert(size() == len, "must be same size");
 162       return;
 163     } else if (entry < current->entry_address()) {
 164       break;
 165     }
 166   }
 167 
 168   // Insert the record into the list.
 169   JsrRecord* swap = record;
 170   JsrRecord* temp = NULL;
 171   for ( ; pos < len; pos++) {
 172     temp = _set->at(pos);
 173     _set->at_put(pos, swap);
 174     swap = temp;
 175   }
 176   _set->append(swap);
 177   assert(size() == len+1, "must be larger");
 178 }
 179 
 180 // ------------------------------------------------------------------
 181 // ciTypeFlow::JsrSet::remove_jsr_record
 182 //
 183 // Remove the JsrRecord with the given return address from the JsrSet.
 184 void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
 185   int len = size();
 186   for (int i = 0; i < len; i++) {
 187     if (record_at(i)->return_address() == return_address) {
 188       // We have found the proper entry.  Remove it from the
 189       // JsrSet and exit.
 190       for (int j = i+1; j < len ; j++) {
 191         _set->at_put(j-1, _set->at(j));
 192       }
 193       _set->trunc_to(len-1);
 194       assert(size() == len-1, "must be smaller");
 195       return;
 196     }
 197   }
 198   assert(false, "verify: returning from invalid subroutine");
 199 }
 200 
 201 // ------------------------------------------------------------------
 202 // ciTypeFlow::JsrSet::apply_control
 203 //
 204 // Apply the effect of a control-flow bytecode on the JsrSet.  The
 205 // only bytecodes that modify the JsrSet are jsr and ret.
 206 void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
 207                                        ciBytecodeStream* str,
 208                                        ciTypeFlow::StateVector* state) {
 209   Bytecodes::Code code = str->cur_bc();
 210   if (code == Bytecodes::_jsr) {
 211     JsrRecord* record =
 212       analyzer->make_jsr_record(str->get_dest(), str->next_bci());
 213     insert_jsr_record(record);
 214   } else if (code == Bytecodes::_jsr_w) {
 215     JsrRecord* record =
 216       analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
 217     insert_jsr_record(record);
 218   } else if (code == Bytecodes::_ret) {
 219     Cell local = state->local(str->get_index());
 220     ciType* return_address = state->type_at(local);
 221     assert(return_address->is_return_address(), "verify: wrong type");
 222     if (size() == 0) {
 223       // Ret-state underflow:  Hit a ret w/o any previous jsrs.  Bail out.
 224       // This can happen when a loop is inside a finally clause (4614060).
 225       analyzer->record_failure("OSR in finally clause");
 226       return;
 227     }
 228     remove_jsr_record(return_address->as_return_address()->bci());
 229   }
 230 }
 231 
 232 #ifndef PRODUCT
 233 // ------------------------------------------------------------------
 234 // ciTypeFlow::JsrSet::print_on
 235 void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
 236   st->print("{ ");
 237   int num_elements = size();
 238   if (num_elements > 0) {
 239     int i = 0;
 240     for( ; i < num_elements - 1; i++) {
 241       _set->at(i)->print_on(st);
 242       st->print(", ");
 243     }
 244     _set->at(i)->print_on(st);
 245     st->print(" ");
 246   }
 247   st->print("}");
 248 }
 249 #endif
 250 
 251 // ciTypeFlow::StateVector
 252 //
 253 // A StateVector summarizes the type information at some point in
 254 // the program.
 255 
 256 // ------------------------------------------------------------------
 257 // ciTypeFlow::StateVector::type_meet
 258 //
 259 // Meet two types.
 260 //
 261 // The semi-lattice of types use by this analysis are modeled on those
 262 // of the verifier.  The lattice is as follows:
 263 //
 264 //        top_type() >= all non-extremal types >= bottom_type
 265 //                             and
 266 //   Every primitive type is comparable only with itself.  The meet of
 267 //   reference types is determined by their kind: instance class,
 268 //   interface, or array class.  The meet of two types of the same
 269 //   kind is their least common ancestor.  The meet of two types of
 270 //   different kinds is always java.lang.Object.
 271 ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
 272   assert(t1 != t2, "checked in caller");
 273   if (t1->equals(top_type())) {
 274     return t2;
 275   } else if (t2->equals(top_type())) {
 276     return t1;
 277   } else if (t1->is_primitive_type() || t2->is_primitive_type()) {
 278     // Special case null_type.  null_type meet any reference type T
 279     // is T.  null_type meet null_type is null_type.
 280     if (t1->equals(null_type())) {
 281       if (!t2->is_primitive_type() || t2->equals(null_type())) {
 282         return t2;
 283       }
 284     } else if (t2->equals(null_type())) {
 285       if (!t1->is_primitive_type()) {
 286         return t1;
 287       }
 288     }
 289 
 290     // At least one of the two types is a non-top primitive type.
 291     // The other type is not equal to it.  Fall to bottom.
 292     return bottom_type();
 293   } else {
 294     // Both types are non-top non-primitive types.  That is,
 295     // both types are either instanceKlasses or arrayKlasses.
 296     ciKlass* object_klass = analyzer->env()->Object_klass();
 297     ciKlass* k1 = t1->as_klass();
 298     ciKlass* k2 = t2->as_klass();
 299     if (k1->equals(object_klass) || k2->equals(object_klass)) {
 300       return object_klass;
 301     } else if (!k1->is_loaded() || !k2->is_loaded()) {
 302       // Unloaded classes fall to java.lang.Object at a merge.
 303       return object_klass;
 304     } else if (k1->is_interface() != k2->is_interface()) {
 305       // When an interface meets a non-interface, we get Object;
 306       // This is what the verifier does.
 307       return object_klass;
 308     } else if (k1->is_array_klass() || k2->is_array_klass()) {
 309       // When an array meets a non-array, we get Object.
 310       // When objArray meets typeArray, we also get Object.
 311       // And when typeArray meets different typeArray, we again get Object.
 312       // But when objArray meets objArray, we look carefully at element types.
 313       if (k1->is_obj_array_klass() && k2->is_obj_array_klass()) {
 314         // Meet the element types, then construct the corresponding array type.
 315         ciKlass* elem1 = k1->as_obj_array_klass()->element_klass();
 316         ciKlass* elem2 = k2->as_obj_array_klass()->element_klass();
 317         ciKlass* elem  = type_meet_internal(elem1, elem2, analyzer)->as_klass();
 318         // Do an easy shortcut if one type is a super of the other.
 319         if (elem == elem1) {
 320           assert(k1 == ciObjArrayKlass::make(elem), "shortcut is OK");
 321           return k1;
 322         } else if (elem == elem2) {
 323           assert(k2 == ciObjArrayKlass::make(elem), "shortcut is OK");
 324           return k2;
 325         } else {
 326           return ciObjArrayKlass::make(elem);
 327         }
 328       } else {
 329         return object_klass;
 330       }
 331     } else {
 332       // Must be two plain old instance klasses.
 333       assert(k1->is_instance_klass(), "previous cases handle non-instances");
 334       assert(k2->is_instance_klass(), "previous cases handle non-instances");
 335       return k1->least_common_ancestor(k2);
 336     }
 337   }
 338 }
 339 
 340 
 341 // ------------------------------------------------------------------
 342 // ciTypeFlow::StateVector::StateVector
 343 //
 344 // Build a new state vector
 345 ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
 346   _outer = analyzer;
 347   _stack_size = -1;
 348   _monitor_count = -1;
 349   // Allocate the _types array
 350   int max_cells = analyzer->max_cells();
 351   _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
 352   for (int i=0; i<max_cells; i++) {
 353     _types[i] = top_type();
 354   }
 355   _trap_bci = -1;
 356   _trap_index = 0;
 357   _def_locals.clear();
 358 }
 359 
 360 
 361 // ------------------------------------------------------------------
 362 // ciTypeFlow::get_start_state
 363 //
 364 // Set this vector to the method entry state.
 365 const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
 366   StateVector* state = new StateVector(this);
 367   if (is_osr_flow()) {
 368     ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
 369     if (non_osr_flow->failing()) {
 370       record_failure(non_osr_flow->failure_reason());
 371       return NULL;
 372     }
 373     JsrSet* jsrs = new JsrSet(NULL, 16);
 374     Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
 375     if (non_osr_block == NULL) {
 376       record_failure("cannot reach OSR point");
 377       return NULL;
 378     }
 379     // load up the non-OSR state at this point
 380     non_osr_block->copy_state_into(state);
 381     int non_osr_start = non_osr_block->start();
 382     if (non_osr_start != start_bci()) {
 383       // must flow forward from it
 384       if (CITraceTypeFlow) {
 385         tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
 386       }
 387       Block* block = block_at(non_osr_start, jsrs);
 388       assert(block->limit() == start_bci(), "must flow forward to start");
 389       flow_block(block, state, jsrs);
 390     }
 391     return state;
 392     // Note:  The code below would be an incorrect for an OSR flow,
 393     // even if it were possible for an OSR entry point to be at bci zero.
 394   }
 395   // "Push" the method signature into the first few locals.
 396   state->set_stack_size(-max_locals());
 397   if (!method()->is_static()) {
 398     state->push(method()->holder());
 399     assert(state->tos() == state->local(0), "");
 400   }
 401   for (ciSignatureStream str(method()->signature());
 402        !str.at_return_type();
 403        str.next()) {
 404     state->push_translate(str.type());
 405   }
 406   // Set the rest of the locals to bottom.
 407   Cell cell = state->next_cell(state->tos());
 408   state->set_stack_size(0);
 409   int limit = state->limit_cell();
 410   for (; cell < limit; cell = state->next_cell(cell)) {
 411     state->set_type_at(cell, state->bottom_type());
 412   }
 413   // Lock an object, if necessary.
 414   state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
 415   return state;
 416 }
 417 
 418 // ------------------------------------------------------------------
 419 // ciTypeFlow::StateVector::copy_into
 420 //
 421 // Copy our value into some other StateVector
 422 void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
 423 const {
 424   copy->set_stack_size(stack_size());
 425   copy->set_monitor_count(monitor_count());
 426   Cell limit = limit_cell();
 427   for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 428     copy->set_type_at(c, type_at(c));
 429   }
 430 }
 431 
 432 // ------------------------------------------------------------------
 433 // ciTypeFlow::StateVector::meet
 434 //
 435 // Meets this StateVector with another, destructively modifying this
 436 // one.  Returns true if any modification takes place.
 437 bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
 438   if (monitor_count() == -1) {
 439     set_monitor_count(incoming->monitor_count());
 440   }
 441   assert(monitor_count() == incoming->monitor_count(), "monitors must match");
 442 
 443   if (stack_size() == -1) {
 444     set_stack_size(incoming->stack_size());
 445     Cell limit = limit_cell();
 446     #ifdef ASSERT
 447     { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 448         assert(type_at(c) == top_type(), "");
 449     } }
 450     #endif
 451     // Make a simple copy of the incoming state.
 452     for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 453       set_type_at(c, incoming->type_at(c));
 454     }
 455     return true;  // it is always different the first time
 456   }
 457 #ifdef ASSERT
 458   if (stack_size() != incoming->stack_size()) {
 459     _outer->method()->print_codes();
 460     tty->print_cr("!!!! Stack size conflict");
 461     tty->print_cr("Current state:");
 462     print_on(tty);
 463     tty->print_cr("Incoming state:");
 464     ((StateVector*)incoming)->print_on(tty);
 465   }
 466 #endif
 467   assert(stack_size() == incoming->stack_size(), "sanity");
 468 
 469   bool different = false;
 470   Cell limit = limit_cell();
 471   for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
 472     ciType* t1 = type_at(c);
 473     ciType* t2 = incoming->type_at(c);
 474     if (!t1->equals(t2)) {
 475       ciType* new_type = type_meet(t1, t2);
 476       if (!t1->equals(new_type)) {
 477         set_type_at(c, new_type);
 478         different = true;
 479       }
 480     }
 481   }
 482   return different;
 483 }
 484 
 485 // ------------------------------------------------------------------
 486 // ciTypeFlow::StateVector::meet_exception
 487 //
 488 // Meets this StateVector with another, destructively modifying this
 489 // one.  The incoming state is coming via an exception.  Returns true
 490 // if any modification takes place.
 491 bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
 492                                      const ciTypeFlow::StateVector* incoming) {
 493   if (monitor_count() == -1) {
 494     set_monitor_count(incoming->monitor_count());
 495   }
 496   assert(monitor_count() == incoming->monitor_count(), "monitors must match");
 497 
 498   if (stack_size() == -1) {
 499     set_stack_size(1);
 500   }
 501 
 502   assert(stack_size() ==  1, "must have one-element stack");
 503 
 504   bool different = false;
 505 
 506   // Meet locals from incoming array.
 507   Cell limit = local(_outer->max_locals()-1);
 508   for (Cell c = start_cell(); c <= limit; c = next_cell(c)) {
 509     ciType* t1 = type_at(c);
 510     ciType* t2 = incoming->type_at(c);
 511     if (!t1->equals(t2)) {
 512       ciType* new_type = type_meet(t1, t2);
 513       if (!t1->equals(new_type)) {
 514         set_type_at(c, new_type);
 515         different = true;
 516       }
 517     }
 518   }
 519 
 520   // Handle stack separately.  When an exception occurs, the
 521   // only stack entry is the exception instance.
 522   ciType* tos_type = type_at_tos();
 523   if (!tos_type->equals(exc)) {
 524     ciType* new_type = type_meet(tos_type, exc);
 525     if (!tos_type->equals(new_type)) {
 526       set_type_at_tos(new_type);
 527       different = true;
 528     }
 529   }
 530 
 531   return different;
 532 }
 533 
 534 // ------------------------------------------------------------------
 535 // ciTypeFlow::StateVector::push_translate
 536 void ciTypeFlow::StateVector::push_translate(ciType* type) {
 537   BasicType basic_type = type->basic_type();
 538   if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
 539       basic_type == T_BYTE    || basic_type == T_SHORT) {
 540     push_int();
 541   } else {
 542     push(type);
 543     if (type->is_two_word()) {
 544       push(half_type(type));
 545     }
 546   }
 547 }
 548 
 549 // ------------------------------------------------------------------
 550 // ciTypeFlow::StateVector::do_aaload
 551 void ciTypeFlow::StateVector::do_aaload(ciBytecodeStream* str) {
 552   pop_int();
 553   ciObjArrayKlass* array_klass = pop_objArray();
 554   if (array_klass == NULL) {
 555     // Did aaload on a null reference; push a null and ignore the exception.
 556     // This instruction will never continue normally.  All we have to do
 557     // is report a value that will meet correctly with any downstream
 558     // reference types on paths that will truly be executed.  This null type
 559     // meets with any reference type to yield that same reference type.
 560     // (The compiler will generate an unconditional exception here.)
 561     push(null_type());
 562     return;
 563   }
 564   if (!array_klass->is_loaded()) {
 565     // Only fails for some -Xcomp runs
 566     trap(str, array_klass,
 567          Deoptimization::make_trap_request
 568          (Deoptimization::Reason_unloaded,
 569           Deoptimization::Action_reinterpret));
 570     return;
 571   }
 572   ciKlass* element_klass = array_klass->element_klass();
 573   if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
 574     Untested("unloaded array element class in ciTypeFlow");
 575     trap(str, element_klass,
 576          Deoptimization::make_trap_request
 577          (Deoptimization::Reason_unloaded,
 578           Deoptimization::Action_reinterpret));
 579   } else {
 580     push_object(element_klass);
 581   }
 582 }
 583 
 584 
 585 // ------------------------------------------------------------------
 586 // ciTypeFlow::StateVector::do_checkcast
 587 void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
 588   bool will_link;
 589   ciKlass* klass = str->get_klass(will_link);
 590   if (!will_link) {
 591     // VM's interpreter will not load 'klass' if object is NULL.
 592     // Type flow after this block may still be needed in two situations:
 593     // 1) C2 uses do_null_assert() and continues compilation for later blocks
 594     // 2) C2 does an OSR compile in a later block (see bug 4778368).
 595     pop_object();
 596     do_null_assert(klass);
 597   } else {
 598     pop_object();
 599     push_object(klass);
 600   }
 601 }
 602 
 603 // ------------------------------------------------------------------
 604 // ciTypeFlow::StateVector::do_getfield
 605 void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
 606   // could add assert here for type of object.
 607   pop_object();
 608   do_getstatic(str);
 609 }
 610 
 611 // ------------------------------------------------------------------
 612 // ciTypeFlow::StateVector::do_getstatic
 613 void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
 614   bool will_link;
 615   ciField* field = str->get_field(will_link);
 616   if (!will_link) {
 617     trap(str, field->holder(), str->get_field_holder_index());
 618   } else {
 619     ciType* field_type = field->type();
 620     if (!field_type->is_loaded()) {
 621       // Normally, we need the field's type to be loaded if we are to
 622       // do anything interesting with its value.
 623       // We used to do this:  trap(str, str->get_field_signature_index());
 624       //
 625       // There is one good reason not to trap here.  Execution can
 626       // get past this "getfield" or "getstatic" if the value of
 627       // the field is null.  As long as the value is null, the class
 628       // does not need to be loaded!  The compiler must assume that
 629       // the value of the unloaded class reference is null; if the code
 630       // ever sees a non-null value, loading has occurred.
 631       //
 632       // This actually happens often enough to be annoying.  If the
 633       // compiler throws an uncommon trap at this bytecode, you can
 634       // get an endless loop of recompilations, when all the code
 635       // needs to do is load a series of null values.  Also, a trap
 636       // here can make an OSR entry point unreachable, triggering the
 637       // assert on non_osr_block in ciTypeFlow::get_start_state.
 638       // (See bug 4379915.)
 639       do_null_assert(field_type->as_klass());
 640     } else {
 641       push_translate(field_type);
 642     }
 643   }
 644 }
 645 
 646 // ------------------------------------------------------------------
 647 // ciTypeFlow::StateVector::do_invoke
 648 void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
 649                                         bool has_receiver) {
 650   bool will_link;
 651   ciSignature* declared_signature = NULL;
 652   ciMethod* callee = str->get_method(will_link, &declared_signature);
 653   assert(declared_signature != NULL, "cannot be null");
 654   if (!will_link) {
 655     // We weren't able to find the method.
 656     if (str->cur_bc() == Bytecodes::_invokedynamic) {
 657       trap(str, NULL,
 658            Deoptimization::make_trap_request
 659            (Deoptimization::Reason_uninitialized,
 660             Deoptimization::Action_reinterpret));
 661     } else {
 662       ciKlass* unloaded_holder = callee->holder();
 663       trap(str, unloaded_holder, str->get_method_holder_index());
 664     }
 665   } else {
 666     // We are using the declared signature here because it might be
 667     // different from the callee signature (Cf. invokedynamic and
 668     // invokehandle).
 669     ciSignatureStream sigstr(declared_signature);
 670     const int arg_size = declared_signature->size();
 671     const int stack_base = stack_size() - arg_size;
 672     int i = 0;
 673     for( ; !sigstr.at_return_type(); sigstr.next()) {
 674       ciType* type = sigstr.type();
 675       ciType* stack_type = type_at(stack(stack_base + i++));
 676       // Do I want to check this type?
 677       // assert(stack_type->is_subtype_of(type), "bad type for field value");
 678       if (type->is_two_word()) {
 679         ciType* stack_type2 = type_at(stack(stack_base + i++));
 680         assert(stack_type2->equals(half_type(type)), "must be 2nd half");
 681       }
 682     }
 683     assert(arg_size == i, "must match");
 684     for (int j = 0; j < arg_size; j++) {
 685       pop();
 686     }
 687     if (has_receiver) {
 688       // Check this?
 689       pop_object();
 690     }
 691     assert(!sigstr.is_done(), "must have return type");
 692     ciType* return_type = sigstr.type();
 693     if (!return_type->is_void()) {
 694       if (!return_type->is_loaded()) {
 695         // As in do_getstatic(), generally speaking, we need the return type to
 696         // be loaded if we are to do anything interesting with its value.
 697         // We used to do this:  trap(str, str->get_method_signature_index());
 698         //
 699         // We do not trap here since execution can get past this invoke if
 700         // the return value is null.  As long as the value is null, the class
 701         // does not need to be loaded!  The compiler must assume that
 702         // the value of the unloaded class reference is null; if the code
 703         // ever sees a non-null value, loading has occurred.
 704         //
 705         // See do_getstatic() for similar explanation, as well as bug 4684993.
 706         do_null_assert(return_type->as_klass());
 707       } else {
 708         push_translate(return_type);
 709       }
 710     }
 711   }
 712 }
 713 
 714 // ------------------------------------------------------------------
 715 // ciTypeFlow::StateVector::do_jsr
 716 void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
 717   push(ciReturnAddress::make(str->next_bci()));
 718 }
 719 
 720 // ------------------------------------------------------------------
 721 // ciTypeFlow::StateVector::do_ldc
 722 void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
 723   ciConstant con = str->get_constant();
 724   BasicType basic_type = con.basic_type();
 725   if (basic_type == T_ILLEGAL) {
 726     // OutOfMemoryError in the CI while loading constant
 727     push_null();
 728     outer()->record_failure("ldc did not link");
 729     return;
 730   }
 731   if (basic_type == T_OBJECT || basic_type == T_ARRAY) {
 732     ciObject* obj = con.as_object();
 733     if (obj->is_null_object()) {
 734       push_null();
 735     } else {
 736       assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
 737       push_object(obj->klass());
 738     }
 739   } else {
 740     push_translate(ciType::make(basic_type));
 741   }
 742 }
 743 
 744 // ------------------------------------------------------------------
 745 // ciTypeFlow::StateVector::do_multianewarray
 746 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
 747   int dimensions = str->get_dimensions();
 748   bool will_link;
 749   ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
 750   if (!will_link) {
 751     trap(str, array_klass, str->get_klass_index());
 752   } else {
 753     for (int i = 0; i < dimensions; i++) {
 754       pop_int();
 755     }
 756     push_object(array_klass);
 757   }
 758 }
 759 
 760 // ------------------------------------------------------------------
 761 // ciTypeFlow::StateVector::do_new
 762 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
 763   bool will_link;
 764   ciKlass* klass = str->get_klass(will_link);
 765   if (!will_link || str->is_unresolved_klass()) {
 766     trap(str, klass, str->get_klass_index());
 767   } else {
 768     push_object(klass);
 769   }
 770 }
 771 
 772 // ------------------------------------------------------------------
 773 // ciTypeFlow::StateVector::do_vnew
 774 void ciTypeFlow::StateVector::do_vnew(ciBytecodeStream* str) {
 775   // This assumes that vnew is only valid in a static value type constructor
 776   ciInstanceKlass* klass = str->method()->holder();
 777   // TODO add additional verification (see InterpreterRuntime::_vnew)
 778   assert(klass->is_valuetype(), "should be value type");
 779   // TODO do check for unresolved?
 780   // TODO value types should not be handled as objects
 781   push_object(klass);
 782 }
 783 
 784 // ------------------------------------------------------------------
 785 // ciTypeFlow::StateVector::do_newarray
 786 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
 787   pop_int();
 788   ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
 789   push_object(klass);
 790 }
 791 
 792 // ------------------------------------------------------------------
 793 // ciTypeFlow::StateVector::do_putfield
 794 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
 795   do_putstatic(str);
 796   if (_trap_bci != -1)  return;  // unloaded field holder, etc.
 797   // could add assert here for type of object.
 798   pop_object();
 799 }
 800 
 801 // ------------------------------------------------------------------
 802 // ciTypeFlow::StateVector::do_putstatic
 803 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
 804   bool will_link;
 805   ciField* field = str->get_field(will_link);
 806   if (!will_link) {
 807     trap(str, field->holder(), str->get_field_holder_index());
 808   } else {
 809     ciType* field_type = field->type();
 810     ciType* type = pop_value();
 811     // Do I want to check this type?
 812     //      assert(type->is_subtype_of(field_type), "bad type for field value");
 813     if (field_type->is_two_word()) {
 814       ciType* type2 = pop_value();
 815       assert(type2->is_two_word(), "must be 2nd half");
 816       assert(type == half_type(type2), "must be 2nd half");
 817     }
 818   }
 819 }
 820 
 821 // ------------------------------------------------------------------
 822 // ciTypeFlow::StateVector::do_ret
 823 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
 824   Cell index = local(str->get_index());
 825 
 826   ciType* address = type_at(index);
 827   assert(address->is_return_address(), "bad return address");
 828   set_type_at(index, bottom_type());
 829 }
 830 
 831 void ciTypeFlow::StateVector::do_vunbox(ciBytecodeStream* str) {
 832   bool will_link;
 833   ciKlass* klass = str->get_klass(will_link);
 834   // TODO: Handle case when class is not loaded.
 835   guarantee(will_link, "Class to which the value-capable class will unbox to must be loaded for JIT compilation");
 836   assert(klass->is_valuetype(), "must be value type");
 837   pop_object();
 838   push_object(klass->as_value_klass());
 839 }
 840 
 841 void ciTypeFlow::StateVector::do_vbox(ciBytecodeStream* str) {
 842   bool will_link;
 843   ciKlass* klass = str->get_klass(will_link);
 844   // TODO: Handle case when class is not loaded.
 845   guarantee(will_link, "Class to which value type will box to must be loaded for JIT compilation");
 846   assert(klass->is_instance_klass(), "must be an instance class");
 847   pop_object();
 848   push_object(klass->as_instance_klass());
 849 }
 850 
 851 // ------------------------------------------------------------------
 852 // ciTypeFlow::StateVector::trap
 853 //
 854 // Stop interpretation of this path with a trap.
 855 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
 856   _trap_bci = str->cur_bci();
 857   _trap_index = index;
 858 
 859   // Log information about this trap:
 860   CompileLog* log = outer()->env()->log();
 861   if (log != NULL) {
 862     int mid = log->identify(outer()->method());
 863     int kid = (klass == NULL)? -1: log->identify(klass);
 864     log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
 865     char buf[100];
 866     log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
 867                                                           index));
 868     if (kid >= 0)
 869       log->print(" klass='%d'", kid);
 870     log->end_elem();
 871   }
 872 }
 873 
 874 // ------------------------------------------------------------------
 875 // ciTypeFlow::StateVector::do_null_assert
 876 // Corresponds to graphKit::do_null_assert.
 877 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
 878   if (unloaded_klass->is_loaded()) {
 879     // We failed to link, but we can still compute with this class,
 880     // since it is loaded somewhere.  The compiler will uncommon_trap
 881     // if the object is not null, but the typeflow pass can not assume
 882     // that the object will be null, otherwise it may incorrectly tell
 883     // the parser that an object is known to be null. 4761344, 4807707
 884     push_object(unloaded_klass);
 885   } else {
 886     // The class is not loaded anywhere.  It is safe to model the
 887     // null in the typestates, because we can compile in a null check
 888     // which will deoptimize us if someone manages to load the
 889     // class later.
 890     push_null();
 891   }
 892 }
 893 
 894 
 895 // ------------------------------------------------------------------
 896 // ciTypeFlow::StateVector::apply_one_bytecode
 897 //
 898 // Apply the effect of one bytecode to this StateVector
 899 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
 900   _trap_bci = -1;
 901   _trap_index = 0;
 902 
 903   if (CITraceTypeFlow) {
 904     tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
 905                   Bytecodes::name(str->cur_bc()));
 906   }
 907 
 908   switch(str->cur_bc()) {
 909   case Bytecodes::_aaload: do_aaload(str);                       break;

 910 

 911   case Bytecodes::_aastore:
 912     {
 913       pop_object();
 914       pop_int();
 915       pop_objArray();
 916       break;
 917     }
 918   case Bytecodes::_aconst_null:
 919     {
 920       push_null();
 921       break;
 922     }
 923   case Bytecodes::_vload:
 924   case Bytecodes::_aload:   load_local_object(str->get_index());    break;
 925   case Bytecodes::_aload_0: load_local_object(0);                   break;
 926   case Bytecodes::_aload_1: load_local_object(1);                   break;
 927   case Bytecodes::_aload_2: load_local_object(2);                   break;
 928   case Bytecodes::_aload_3: load_local_object(3);                   break;
 929 
 930   case Bytecodes::_anewarray:
 931     {
 932       pop_int();
 933       bool will_link;
 934       ciKlass* element_klass = str->get_klass(will_link);
 935       if (!will_link) {
 936         trap(str, element_klass, str->get_klass_index());
 937       } else {
 938         push_object(ciObjArrayKlass::make(element_klass));
 939       }
 940       break;
 941     }
 942   case Bytecodes::_areturn:
 943   case Bytecodes::_vreturn:
 944   case Bytecodes::_ifnonnull:
 945   case Bytecodes::_ifnull:
 946     {
 947       pop_object();
 948       break;
 949     }
 950   case Bytecodes::_monitorenter:
 951     {
 952       pop_object();
 953       set_monitor_count(monitor_count() + 1);
 954       break;
 955     }
 956   case Bytecodes::_monitorexit:
 957     {
 958       pop_object();
 959       assert(monitor_count() > 0, "must be a monitor to exit from");
 960       set_monitor_count(monitor_count() - 1);
 961       break;
 962     }
 963   case Bytecodes::_arraylength:
 964     {
 965       pop_array();
 966       push_int();
 967       break;
 968     }
 969   case Bytecodes::_vstore:
 970   case Bytecodes::_astore:   store_local_object(str->get_index());  break;
 971   case Bytecodes::_astore_0: store_local_object(0);                 break;
 972   case Bytecodes::_astore_1: store_local_object(1);                 break;
 973   case Bytecodes::_astore_2: store_local_object(2);                 break;
 974   case Bytecodes::_astore_3: store_local_object(3);                 break;
 975 
 976   case Bytecodes::_athrow:
 977     {
 978       NEEDS_CLEANUP;
 979       pop_object();
 980       break;
 981     }
 982   case Bytecodes::_baload:
 983   case Bytecodes::_caload:
 984   case Bytecodes::_iaload:
 985   case Bytecodes::_saload:
 986     {
 987       pop_int();
 988       ciTypeArrayKlass* array_klass = pop_typeArray();
 989       // Put assert here for right type?
 990       push_int();
 991       break;
 992     }
 993   case Bytecodes::_bastore:
 994   case Bytecodes::_castore:
 995   case Bytecodes::_iastore:
 996   case Bytecodes::_sastore:
 997     {
 998       pop_int();
 999       pop_int();
1000       pop_typeArray();
1001       // assert here?
1002       break;
1003     }
1004   case Bytecodes::_bipush:
1005   case Bytecodes::_iconst_m1:
1006   case Bytecodes::_iconst_0:
1007   case Bytecodes::_iconst_1:
1008   case Bytecodes::_iconst_2:
1009   case Bytecodes::_iconst_3:
1010   case Bytecodes::_iconst_4:
1011   case Bytecodes::_iconst_5:
1012   case Bytecodes::_sipush:
1013     {
1014       push_int();
1015       break;
1016     }
1017   case Bytecodes::_checkcast: do_checkcast(str);                  break;
1018 
1019   case Bytecodes::_d2f:
1020     {
1021       pop_double();
1022       push_float();
1023       break;
1024     }
1025   case Bytecodes::_d2i:
1026     {
1027       pop_double();
1028       push_int();
1029       break;
1030     }
1031   case Bytecodes::_d2l:
1032     {
1033       pop_double();
1034       push_long();
1035       break;
1036     }
1037   case Bytecodes::_dadd:
1038   case Bytecodes::_ddiv:
1039   case Bytecodes::_dmul:
1040   case Bytecodes::_drem:
1041   case Bytecodes::_dsub:
1042     {
1043       pop_double();
1044       pop_double();
1045       push_double();
1046       break;
1047     }
1048   case Bytecodes::_daload:
1049     {
1050       pop_int();
1051       ciTypeArrayKlass* array_klass = pop_typeArray();
1052       // Put assert here for right type?
1053       push_double();
1054       break;
1055     }
1056   case Bytecodes::_dastore:
1057     {
1058       pop_double();
1059       pop_int();
1060       pop_typeArray();
1061       // assert here?
1062       break;
1063     }
1064   case Bytecodes::_dcmpg:
1065   case Bytecodes::_dcmpl:
1066     {
1067       pop_double();
1068       pop_double();
1069       push_int();
1070       break;
1071     }
1072   case Bytecodes::_dconst_0:
1073   case Bytecodes::_dconst_1:
1074     {
1075       push_double();
1076       break;
1077     }
1078   case Bytecodes::_dload:   load_local_double(str->get_index());    break;
1079   case Bytecodes::_dload_0: load_local_double(0);                   break;
1080   case Bytecodes::_dload_1: load_local_double(1);                   break;
1081   case Bytecodes::_dload_2: load_local_double(2);                   break;
1082   case Bytecodes::_dload_3: load_local_double(3);                   break;
1083 
1084   case Bytecodes::_dneg:
1085     {
1086       pop_double();
1087       push_double();
1088       break;
1089     }
1090   case Bytecodes::_dreturn:
1091     {
1092       pop_double();
1093       break;
1094     }
1095   case Bytecodes::_dstore:   store_local_double(str->get_index());  break;
1096   case Bytecodes::_dstore_0: store_local_double(0);                 break;
1097   case Bytecodes::_dstore_1: store_local_double(1);                 break;
1098   case Bytecodes::_dstore_2: store_local_double(2);                 break;
1099   case Bytecodes::_dstore_3: store_local_double(3);                 break;
1100 
1101   case Bytecodes::_dup:
1102     {
1103       push(type_at_tos());
1104       break;
1105     }
1106   case Bytecodes::_dup_x1:
1107     {
1108       ciType* value1 = pop_value();
1109       ciType* value2 = pop_value();
1110       push(value1);
1111       push(value2);
1112       push(value1);
1113       break;
1114     }
1115   case Bytecodes::_dup_x2:
1116     {
1117       ciType* value1 = pop_value();
1118       ciType* value2 = pop_value();
1119       ciType* value3 = pop_value();
1120       push(value1);
1121       push(value3);
1122       push(value2);
1123       push(value1);
1124       break;
1125     }
1126   case Bytecodes::_dup2:
1127     {
1128       ciType* value1 = pop_value();
1129       ciType* value2 = pop_value();
1130       push(value2);
1131       push(value1);
1132       push(value2);
1133       push(value1);
1134       break;
1135     }
1136   case Bytecodes::_dup2_x1:
1137     {
1138       ciType* value1 = pop_value();
1139       ciType* value2 = pop_value();
1140       ciType* value3 = pop_value();
1141       push(value2);
1142       push(value1);
1143       push(value3);
1144       push(value2);
1145       push(value1);
1146       break;
1147     }
1148   case Bytecodes::_dup2_x2:
1149     {
1150       ciType* value1 = pop_value();
1151       ciType* value2 = pop_value();
1152       ciType* value3 = pop_value();
1153       ciType* value4 = pop_value();
1154       push(value2);
1155       push(value1);
1156       push(value4);
1157       push(value3);
1158       push(value2);
1159       push(value1);
1160       break;
1161     }
1162   case Bytecodes::_f2d:
1163     {
1164       pop_float();
1165       push_double();
1166       break;
1167     }
1168   case Bytecodes::_f2i:
1169     {
1170       pop_float();
1171       push_int();
1172       break;
1173     }
1174   case Bytecodes::_f2l:
1175     {
1176       pop_float();
1177       push_long();
1178       break;
1179     }
1180   case Bytecodes::_fadd:
1181   case Bytecodes::_fdiv:
1182   case Bytecodes::_fmul:
1183   case Bytecodes::_frem:
1184   case Bytecodes::_fsub:
1185     {
1186       pop_float();
1187       pop_float();
1188       push_float();
1189       break;
1190     }
1191   case Bytecodes::_faload:
1192     {
1193       pop_int();
1194       ciTypeArrayKlass* array_klass = pop_typeArray();
1195       // Put assert here.
1196       push_float();
1197       break;
1198     }
1199   case Bytecodes::_fastore:
1200     {
1201       pop_float();
1202       pop_int();
1203       ciTypeArrayKlass* array_klass = pop_typeArray();
1204       // Put assert here.
1205       break;
1206     }
1207   case Bytecodes::_fcmpg:
1208   case Bytecodes::_fcmpl:
1209     {
1210       pop_float();
1211       pop_float();
1212       push_int();
1213       break;
1214     }
1215   case Bytecodes::_fconst_0:
1216   case Bytecodes::_fconst_1:
1217   case Bytecodes::_fconst_2:
1218     {
1219       push_float();
1220       break;
1221     }
1222   case Bytecodes::_fload:   load_local_float(str->get_index());     break;
1223   case Bytecodes::_fload_0: load_local_float(0);                    break;
1224   case Bytecodes::_fload_1: load_local_float(1);                    break;
1225   case Bytecodes::_fload_2: load_local_float(2);                    break;
1226   case Bytecodes::_fload_3: load_local_float(3);                    break;
1227 
1228   case Bytecodes::_fneg:
1229     {
1230       pop_float();
1231       push_float();
1232       break;
1233     }
1234   case Bytecodes::_freturn:
1235     {
1236       pop_float();
1237       break;
1238     }
1239   case Bytecodes::_fstore:    store_local_float(str->get_index());   break;
1240   case Bytecodes::_fstore_0:  store_local_float(0);                  break;
1241   case Bytecodes::_fstore_1:  store_local_float(1);                  break;
1242   case Bytecodes::_fstore_2:  store_local_float(2);                  break;
1243   case Bytecodes::_fstore_3:  store_local_float(3);                  break;
1244 
1245   case Bytecodes::_vgetfield:
1246   case Bytecodes::_getfield:  do_getfield(str);                      break;
1247   case Bytecodes::_getstatic: do_getstatic(str);                     break;
1248 
1249   case Bytecodes::_goto:
1250   case Bytecodes::_goto_w:
1251   case Bytecodes::_nop:
1252   case Bytecodes::_return:
1253     {
1254       // do nothing.
1255       break;
1256     }
1257   case Bytecodes::_i2b:
1258   case Bytecodes::_i2c:
1259   case Bytecodes::_i2s:
1260   case Bytecodes::_ineg:
1261     {
1262       pop_int();
1263       push_int();
1264       break;
1265     }
1266   case Bytecodes::_i2d:
1267     {
1268       pop_int();
1269       push_double();
1270       break;
1271     }
1272   case Bytecodes::_i2f:
1273     {
1274       pop_int();
1275       push_float();
1276       break;
1277     }
1278   case Bytecodes::_i2l:
1279     {
1280       pop_int();
1281       push_long();
1282       break;
1283     }
1284   case Bytecodes::_iadd:
1285   case Bytecodes::_iand:
1286   case Bytecodes::_idiv:
1287   case Bytecodes::_imul:
1288   case Bytecodes::_ior:
1289   case Bytecodes::_irem:
1290   case Bytecodes::_ishl:
1291   case Bytecodes::_ishr:
1292   case Bytecodes::_isub:
1293   case Bytecodes::_iushr:
1294   case Bytecodes::_ixor:
1295     {
1296       pop_int();
1297       pop_int();
1298       push_int();
1299       break;
1300     }
1301   case Bytecodes::_if_acmpeq:
1302   case Bytecodes::_if_acmpne:
1303     {
1304       pop_object();
1305       pop_object();
1306       break;
1307     }
1308   case Bytecodes::_if_icmpeq:
1309   case Bytecodes::_if_icmpge:
1310   case Bytecodes::_if_icmpgt:
1311   case Bytecodes::_if_icmple:
1312   case Bytecodes::_if_icmplt:
1313   case Bytecodes::_if_icmpne:
1314     {
1315       pop_int();
1316       pop_int();
1317       break;
1318     }
1319   case Bytecodes::_ifeq:
1320   case Bytecodes::_ifle:
1321   case Bytecodes::_iflt:
1322   case Bytecodes::_ifge:
1323   case Bytecodes::_ifgt:
1324   case Bytecodes::_ifne:
1325   case Bytecodes::_ireturn:
1326   case Bytecodes::_lookupswitch:
1327   case Bytecodes::_tableswitch:
1328     {
1329       pop_int();
1330       break;
1331     }
1332   case Bytecodes::_iinc:
1333     {
1334       int lnum = str->get_index();
1335       check_int(local(lnum));
1336       store_to_local(lnum);
1337       break;
1338     }
1339   case Bytecodes::_iload:   load_local_int(str->get_index()); break;
1340   case Bytecodes::_iload_0: load_local_int(0);                      break;
1341   case Bytecodes::_iload_1: load_local_int(1);                      break;
1342   case Bytecodes::_iload_2: load_local_int(2);                      break;
1343   case Bytecodes::_iload_3: load_local_int(3);                      break;
1344 
1345   case Bytecodes::_instanceof:
1346     {
1347       // Check for uncommon trap:
1348       do_checkcast(str);
1349       pop_object();
1350       push_int();
1351       break;
1352     }
1353   case Bytecodes::_invokeinterface: do_invoke(str, true);           break;
1354   case Bytecodes::_invokespecial:   do_invoke(str, true);           break;
1355   case Bytecodes::_invokestatic:    do_invoke(str, false);          break;
1356   case Bytecodes::_invokedirect:
1357   case Bytecodes::_invokevirtual:   do_invoke(str, true);           break;
1358   case Bytecodes::_invokedynamic:   do_invoke(str, false);          break;
1359 
1360   case Bytecodes::_istore:   store_local_int(str->get_index());     break;
1361   case Bytecodes::_istore_0: store_local_int(0);                    break;
1362   case Bytecodes::_istore_1: store_local_int(1);                    break;
1363   case Bytecodes::_istore_2: store_local_int(2);                    break;
1364   case Bytecodes::_istore_3: store_local_int(3);                    break;
1365 
1366   case Bytecodes::_jsr:
1367   case Bytecodes::_jsr_w: do_jsr(str);                              break;
1368 
1369   case Bytecodes::_l2d:
1370     {
1371       pop_long();
1372       push_double();
1373       break;
1374     }
1375   case Bytecodes::_l2f:
1376     {
1377       pop_long();
1378       push_float();
1379       break;
1380     }
1381   case Bytecodes::_l2i:
1382     {
1383       pop_long();
1384       push_int();
1385       break;
1386     }
1387   case Bytecodes::_ladd:
1388   case Bytecodes::_land:
1389   case Bytecodes::_ldiv:
1390   case Bytecodes::_lmul:
1391   case Bytecodes::_lor:
1392   case Bytecodes::_lrem:
1393   case Bytecodes::_lsub:
1394   case Bytecodes::_lxor:
1395     {
1396       pop_long();
1397       pop_long();
1398       push_long();
1399       break;
1400     }
1401   case Bytecodes::_laload:
1402     {
1403       pop_int();
1404       ciTypeArrayKlass* array_klass = pop_typeArray();
1405       // Put assert here for right type?
1406       push_long();
1407       break;
1408     }
1409   case Bytecodes::_lastore:
1410     {
1411       pop_long();
1412       pop_int();
1413       pop_typeArray();
1414       // assert here?
1415       break;
1416     }
1417   case Bytecodes::_lcmp:
1418     {
1419       pop_long();
1420       pop_long();
1421       push_int();
1422       break;
1423     }
1424   case Bytecodes::_lconst_0:
1425   case Bytecodes::_lconst_1:
1426     {
1427       push_long();
1428       break;
1429     }
1430   case Bytecodes::_ldc:
1431   case Bytecodes::_ldc_w:
1432   case Bytecodes::_ldc2_w:
1433     {
1434       do_ldc(str);
1435       break;
1436     }
1437 
1438   case Bytecodes::_lload:   load_local_long(str->get_index());      break;
1439   case Bytecodes::_lload_0: load_local_long(0);                     break;
1440   case Bytecodes::_lload_1: load_local_long(1);                     break;
1441   case Bytecodes::_lload_2: load_local_long(2);                     break;
1442   case Bytecodes::_lload_3: load_local_long(3);                     break;
1443 
1444   case Bytecodes::_lneg:
1445     {
1446       pop_long();
1447       push_long();
1448       break;
1449     }
1450   case Bytecodes::_lreturn:
1451     {
1452       pop_long();
1453       break;
1454     }
1455   case Bytecodes::_lshl:
1456   case Bytecodes::_lshr:
1457   case Bytecodes::_lushr:
1458     {
1459       pop_int();
1460       pop_long();
1461       push_long();
1462       break;
1463     }
1464   case Bytecodes::_lstore:   store_local_long(str->get_index());    break;
1465   case Bytecodes::_lstore_0: store_local_long(0);                   break;
1466   case Bytecodes::_lstore_1: store_local_long(1);                   break;
1467   case Bytecodes::_lstore_2: store_local_long(2);                   break;
1468   case Bytecodes::_lstore_3: store_local_long(3);                   break;
1469 
1470   case Bytecodes::_multianewarray: do_multianewarray(str);          break;
1471   case Bytecodes::_new:      do_new(str);                           break;
1472   case Bytecodes::_vnew:     do_vnew(str);                          break;
1473 
1474   case Bytecodes::_newarray: do_newarray(str);                      break;
1475 
1476   case Bytecodes::_pop:
1477     {
1478       pop();
1479       break;
1480     }
1481   case Bytecodes::_pop2:
1482     {
1483       pop();
1484       pop();
1485       break;
1486     }
1487 
1488   case Bytecodes::_putfield:       do_putfield(str);                 break;
1489   case Bytecodes::_putstatic:      do_putstatic(str);                break;
1490 
1491   case Bytecodes::_ret: do_ret(str);                                 break;
1492 
1493   case Bytecodes::_swap:
1494     {
1495       ciType* value1 = pop_value();
1496       ciType* value2 = pop_value();
1497       push(value1);
1498       push(value2);
1499       break;
1500     }
1501   case Bytecodes::_vunbox:
1502   {
1503     do_vunbox(str);
1504     break;
1505   }
1506   case Bytecodes::_vbox:
1507   {
1508     do_vbox(str);
1509     break;
1510   }
1511   case Bytecodes::_wide:
1512   default:
1513     {
1514       // The iterator should skip this.
1515       ShouldNotReachHere();
1516       break;
1517     }
1518   }
1519 
1520   if (CITraceTypeFlow) {
1521     print_on(tty);
1522   }
1523 
1524   return (_trap_bci != -1);
1525 }
1526 
1527 #ifndef PRODUCT
1528 // ------------------------------------------------------------------
1529 // ciTypeFlow::StateVector::print_cell_on
1530 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1531   ciType* type = type_at(c);
1532   if (type == top_type()) {
1533     st->print("top");
1534   } else if (type == bottom_type()) {
1535     st->print("bottom");
1536   } else if (type == null_type()) {
1537     st->print("null");
1538   } else if (type == long2_type()) {
1539     st->print("long2");
1540   } else if (type == double2_type()) {
1541     st->print("double2");
1542   } else if (is_int(type)) {
1543     st->print("int");
1544   } else if (is_long(type)) {
1545     st->print("long");
1546   } else if (is_float(type)) {
1547     st->print("float");
1548   } else if (is_double(type)) {
1549     st->print("double");
1550   } else if (type->is_return_address()) {
1551     st->print("address(%d)", type->as_return_address()->bci());
1552   } else {
1553     if (type->is_klass()) {
1554       type->as_klass()->name()->print_symbol_on(st);
1555     } else {
1556       st->print("UNEXPECTED TYPE");
1557       type->print();
1558     }
1559   }
1560 }
1561 
1562 // ------------------------------------------------------------------
1563 // ciTypeFlow::StateVector::print_on
1564 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1565   int num_locals   = _outer->max_locals();
1566   int num_stack    = stack_size();
1567   int num_monitors = monitor_count();
1568   st->print_cr("  State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1569   if (num_stack >= 0) {
1570     int i;
1571     for (i = 0; i < num_locals; i++) {
1572       st->print("    local %2d : ", i);
1573       print_cell_on(st, local(i));
1574       st->cr();
1575     }
1576     for (i = 0; i < num_stack; i++) {
1577       st->print("    stack %2d : ", i);
1578       print_cell_on(st, stack(i));
1579       st->cr();
1580     }
1581   }
1582 }
1583 #endif
1584 
1585 
1586 // ------------------------------------------------------------------
1587 // ciTypeFlow::SuccIter::next
1588 //
1589 void ciTypeFlow::SuccIter::next() {
1590   int succ_ct = _pred->successors()->length();
1591   int next = _index + 1;
1592   if (next < succ_ct) {
1593     _index = next;
1594     _succ = _pred->successors()->at(next);
1595     return;
1596   }
1597   for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1598     // Do not compile any code for unloaded exception types.
1599     // Following compiler passes are responsible for doing this also.
1600     ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1601     if (exception_klass->is_loaded()) {
1602       _index = next;
1603       _succ = _pred->exceptions()->at(i);
1604       return;
1605     }
1606     next++;
1607   }
1608   _index = -1;
1609   _succ = NULL;
1610 }
1611 
1612 // ------------------------------------------------------------------
1613 // ciTypeFlow::SuccIter::set_succ
1614 //
1615 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1616   int succ_ct = _pred->successors()->length();
1617   if (_index < succ_ct) {
1618     _pred->successors()->at_put(_index, succ);
1619   } else {
1620     int idx = _index - succ_ct;
1621     _pred->exceptions()->at_put(idx, succ);
1622   }
1623 }
1624 
1625 // ciTypeFlow::Block
1626 //
1627 // A basic block.
1628 
1629 // ------------------------------------------------------------------
1630 // ciTypeFlow::Block::Block
1631 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1632                          ciBlock *ciblk,
1633                          ciTypeFlow::JsrSet* jsrs) {
1634   _ciblock = ciblk;
1635   _exceptions = NULL;
1636   _exc_klasses = NULL;
1637   _successors = NULL;
1638   _predecessors = new (outer->arena()) GrowableArray<Block*>(outer->arena(), 1, 0, NULL);
1639   _state = new (outer->arena()) StateVector(outer);
1640   JsrSet* new_jsrs =
1641     new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1642   jsrs->copy_into(new_jsrs);
1643   _jsrs = new_jsrs;
1644   _next = NULL;
1645   _on_work_list = false;
1646   _backedge_copy = false;
1647   _has_monitorenter = false;
1648   _trap_bci = -1;
1649   _trap_index = 0;
1650   df_init();
1651 
1652   if (CITraceTypeFlow) {
1653     tty->print_cr(">> Created new block");
1654     print_on(tty);
1655   }
1656 
1657   assert(this->outer() == outer, "outer link set up");
1658   assert(!outer->have_block_count(), "must not have mapped blocks yet");
1659 }
1660 
1661 // ------------------------------------------------------------------
1662 // ciTypeFlow::Block::df_init
1663 void ciTypeFlow::Block::df_init() {
1664   _pre_order = -1; assert(!has_pre_order(), "");
1665   _post_order = -1; assert(!has_post_order(), "");
1666   _loop = NULL;
1667   _irreducible_entry = false;
1668   _rpo_next = NULL;
1669 }
1670 
1671 // ------------------------------------------------------------------
1672 // ciTypeFlow::Block::successors
1673 //
1674 // Get the successors for this Block.
1675 GrowableArray<ciTypeFlow::Block*>*
1676 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1677                               ciTypeFlow::StateVector* state,
1678                               ciTypeFlow::JsrSet* jsrs) {
1679   if (_successors == NULL) {
1680     if (CITraceTypeFlow) {
1681       tty->print(">> Computing successors for block ");
1682       print_value_on(tty);
1683       tty->cr();
1684     }
1685 
1686     ciTypeFlow* analyzer = outer();
1687     Arena* arena = analyzer->arena();
1688     Block* block = NULL;
1689     bool has_successor = !has_trap() &&
1690                          (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1691     if (!has_successor) {
1692       _successors =
1693         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1694       // No successors
1695     } else if (control() == ciBlock::fall_through_bci) {
1696       assert(str->cur_bci() == limit(), "bad block end");
1697       // This block simply falls through to the next.
1698       _successors =
1699         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1700 
1701       Block* block = analyzer->block_at(limit(), _jsrs);
1702       assert(_successors->length() == FALL_THROUGH, "");
1703       _successors->append(block);
1704     } else {
1705       int current_bci = str->cur_bci();
1706       int next_bci = str->next_bci();
1707       int branch_bci = -1;
1708       Block* target = NULL;
1709       assert(str->next_bci() == limit(), "bad block end");
1710       // This block is not a simple fall-though.  Interpret
1711       // the current bytecode to find our successors.
1712       switch (str->cur_bc()) {
1713       case Bytecodes::_ifeq:         case Bytecodes::_ifne:
1714       case Bytecodes::_iflt:         case Bytecodes::_ifge:
1715       case Bytecodes::_ifgt:         case Bytecodes::_ifle:
1716       case Bytecodes::_if_icmpeq:    case Bytecodes::_if_icmpne:
1717       case Bytecodes::_if_icmplt:    case Bytecodes::_if_icmpge:
1718       case Bytecodes::_if_icmpgt:    case Bytecodes::_if_icmple:
1719       case Bytecodes::_if_acmpeq:    case Bytecodes::_if_acmpne:
1720       case Bytecodes::_ifnull:       case Bytecodes::_ifnonnull:
1721         // Our successors are the branch target and the next bci.
1722         branch_bci = str->get_dest();
1723         _successors =
1724           new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1725         assert(_successors->length() == IF_NOT_TAKEN, "");
1726         _successors->append(analyzer->block_at(next_bci, jsrs));
1727         assert(_successors->length() == IF_TAKEN, "");
1728         _successors->append(analyzer->block_at(branch_bci, jsrs));
1729         break;
1730 
1731       case Bytecodes::_goto:
1732         branch_bci = str->get_dest();
1733         _successors =
1734           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1735         assert(_successors->length() == GOTO_TARGET, "");
1736         _successors->append(analyzer->block_at(branch_bci, jsrs));
1737         break;
1738 
1739       case Bytecodes::_jsr:
1740         branch_bci = str->get_dest();
1741         _successors =
1742           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1743         assert(_successors->length() == GOTO_TARGET, "");
1744         _successors->append(analyzer->block_at(branch_bci, jsrs));
1745         break;
1746 
1747       case Bytecodes::_goto_w:
1748       case Bytecodes::_jsr_w:
1749         _successors =
1750           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1751         assert(_successors->length() == GOTO_TARGET, "");
1752         _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1753         break;
1754 
1755       case Bytecodes::_tableswitch:  {
1756         Bytecode_tableswitch tableswitch(str);
1757 
1758         int len = tableswitch.length();
1759         _successors =
1760           new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1761         int bci = current_bci + tableswitch.default_offset();
1762         Block* block = analyzer->block_at(bci, jsrs);
1763         assert(_successors->length() == SWITCH_DEFAULT, "");
1764         _successors->append(block);
1765         while (--len >= 0) {
1766           int bci = current_bci + tableswitch.dest_offset_at(len);
1767           block = analyzer->block_at(bci, jsrs);
1768           assert(_successors->length() >= SWITCH_CASES, "");
1769           _successors->append_if_missing(block);
1770         }
1771         break;
1772       }
1773 
1774       case Bytecodes::_lookupswitch: {
1775         Bytecode_lookupswitch lookupswitch(str);
1776 
1777         int npairs = lookupswitch.number_of_pairs();
1778         _successors =
1779           new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1780         int bci = current_bci + lookupswitch.default_offset();
1781         Block* block = analyzer->block_at(bci, jsrs);
1782         assert(_successors->length() == SWITCH_DEFAULT, "");
1783         _successors->append(block);
1784         while(--npairs >= 0) {
1785           LookupswitchPair pair = lookupswitch.pair_at(npairs);
1786           int bci = current_bci + pair.offset();
1787           Block* block = analyzer->block_at(bci, jsrs);
1788           assert(_successors->length() >= SWITCH_CASES, "");
1789           _successors->append_if_missing(block);
1790         }
1791         break;
1792       }
1793 
1794       case Bytecodes::_athrow:
1795       case Bytecodes::_ireturn:
1796       case Bytecodes::_lreturn:
1797       case Bytecodes::_freturn:
1798       case Bytecodes::_dreturn:
1799       case Bytecodes::_areturn:
1800       case Bytecodes::_vreturn:
1801       case Bytecodes::_return:
1802         _successors =
1803           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1804         // No successors
1805         break;
1806 
1807       case Bytecodes::_ret: {
1808         _successors =
1809           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1810 
1811         Cell local = state->local(str->get_index());
1812         ciType* return_address = state->type_at(local);
1813         assert(return_address->is_return_address(), "verify: wrong type");
1814         int bci = return_address->as_return_address()->bci();
1815         assert(_successors->length() == GOTO_TARGET, "");
1816         _successors->append(analyzer->block_at(bci, jsrs));
1817         break;
1818       }
1819 
1820       case Bytecodes::_wide:
1821       default:
1822         ShouldNotReachHere();
1823         break;
1824       }
1825     }
1826 
1827     // Set predecessor information
1828     for (int i = 0; i < _successors->length(); i++) {
1829       Block* block = _successors->at(i);
1830       block->predecessors()->append(this);
1831     }
1832   }
1833   return _successors;
1834 }
1835 
1836 // ------------------------------------------------------------------
1837 // ciTypeFlow::Block:compute_exceptions
1838 //
1839 // Compute the exceptional successors and types for this Block.
1840 void ciTypeFlow::Block::compute_exceptions() {
1841   assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1842 
1843   if (CITraceTypeFlow) {
1844     tty->print(">> Computing exceptions for block ");
1845     print_value_on(tty);
1846     tty->cr();
1847   }
1848 
1849   ciTypeFlow* analyzer = outer();
1850   Arena* arena = analyzer->arena();
1851 
1852   // Any bci in the block will do.
1853   ciExceptionHandlerStream str(analyzer->method(), start());
1854 
1855   // Allocate our growable arrays.
1856   int exc_count = str.count();
1857   _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1858   _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1859                                                              0, NULL);
1860 
1861   for ( ; !str.is_done(); str.next()) {
1862     ciExceptionHandler* handler = str.handler();
1863     int bci = handler->handler_bci();
1864     ciInstanceKlass* klass = NULL;
1865     if (bci == -1) {
1866       // There is no catch all.  It is possible to exit the method.
1867       break;
1868     }
1869     if (handler->is_catch_all()) {
1870       klass = analyzer->env()->Throwable_klass();
1871     } else {
1872       klass = handler->catch_klass();
1873     }
1874     Block* block = analyzer->block_at(bci, _jsrs);
1875     _exceptions->append(block);
1876     block->predecessors()->append(this);
1877     _exc_klasses->append(klass);
1878   }
1879 }
1880 
1881 // ------------------------------------------------------------------
1882 // ciTypeFlow::Block::set_backedge_copy
1883 // Use this only to make a pre-existing public block into a backedge copy.
1884 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1885   assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1886   _backedge_copy = z;
1887 }
1888 
1889 // ------------------------------------------------------------------
1890 // ciTypeFlow::Block::is_clonable_exit
1891 //
1892 // At most 2 normal successors, one of which continues looping,
1893 // and all exceptional successors must exit.
1894 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1895   int normal_cnt  = 0;
1896   int in_loop_cnt = 0;
1897   for (SuccIter iter(this); !iter.done(); iter.next()) {
1898     Block* succ = iter.succ();
1899     if (iter.is_normal_ctrl()) {
1900       if (++normal_cnt > 2) return false;
1901       if (lp->contains(succ->loop())) {
1902         if (++in_loop_cnt > 1) return false;
1903       }
1904     } else {
1905       if (lp->contains(succ->loop())) return false;
1906     }
1907   }
1908   return in_loop_cnt == 1;
1909 }
1910 
1911 // ------------------------------------------------------------------
1912 // ciTypeFlow::Block::looping_succ
1913 //
1914 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1915   assert(successors()->length() <= 2, "at most 2 normal successors");
1916   for (SuccIter iter(this); !iter.done(); iter.next()) {
1917     Block* succ = iter.succ();
1918     if (lp->contains(succ->loop())) {
1919       return succ;
1920     }
1921   }
1922   return NULL;
1923 }
1924 
1925 #ifndef PRODUCT
1926 // ------------------------------------------------------------------
1927 // ciTypeFlow::Block::print_value_on
1928 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1929   if (has_pre_order()) st->print("#%-2d ", pre_order());
1930   if (has_rpo())       st->print("rpo#%-2d ", rpo());
1931   st->print("[%d - %d)", start(), limit());
1932   if (is_loop_head()) st->print(" lphd");
1933   if (is_irreducible_entry()) st->print(" irred");
1934   if (_jsrs->size() > 0) { st->print("/");  _jsrs->print_on(st); }
1935   if (is_backedge_copy())  st->print("/backedge_copy");
1936 }
1937 
1938 // ------------------------------------------------------------------
1939 // ciTypeFlow::Block::print_on
1940 void ciTypeFlow::Block::print_on(outputStream* st) const {
1941   if ((Verbose || WizardMode) && (limit() >= 0)) {
1942     // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1943     outer()->method()->print_codes_on(start(), limit(), st);
1944   }
1945   st->print_cr("  ====================================================  ");
1946   st->print ("  ");
1947   print_value_on(st);
1948   st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1949   if (loop() && loop()->parent() != NULL) {
1950     st->print(" loops:");
1951     Loop* lp = loop();
1952     do {
1953       st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
1954       if (lp->is_irreducible()) st->print("(ir)");
1955       lp = lp->parent();
1956     } while (lp->parent() != NULL);
1957   }
1958   st->cr();
1959   _state->print_on(st);
1960   if (_successors == NULL) {
1961     st->print_cr("  No successor information");
1962   } else {
1963     int num_successors = _successors->length();
1964     st->print_cr("  Successors : %d", num_successors);
1965     for (int i = 0; i < num_successors; i++) {
1966       Block* successor = _successors->at(i);
1967       st->print("    ");
1968       successor->print_value_on(st);
1969       st->cr();
1970     }
1971   }
1972   if (_predecessors == NULL) {
1973     st->print_cr("  No predecessor information");
1974   } else {
1975     int num_predecessors = _predecessors->length();
1976     st->print_cr("  Predecessors : %d", num_predecessors);
1977     for (int i = 0; i < num_predecessors; i++) {
1978       Block* predecessor = _predecessors->at(i);
1979       st->print("    ");
1980       predecessor->print_value_on(st);
1981       st->cr();
1982     }
1983   }
1984   if (_exceptions == NULL) {
1985     st->print_cr("  No exception information");
1986   } else {
1987     int num_exceptions = _exceptions->length();
1988     st->print_cr("  Exceptions : %d", num_exceptions);
1989     for (int i = 0; i < num_exceptions; i++) {
1990       Block* exc_succ = _exceptions->at(i);
1991       ciInstanceKlass* exc_klass = _exc_klasses->at(i);
1992       st->print("    ");
1993       exc_succ->print_value_on(st);
1994       st->print(" -- ");
1995       exc_klass->name()->print_symbol_on(st);
1996       st->cr();
1997     }
1998   }
1999   if (has_trap()) {
2000     st->print_cr("  Traps on %d with trap index %d", trap_bci(), trap_index());
2001   }
2002   st->print_cr("  ====================================================  ");
2003 }
2004 #endif
2005 
2006 #ifndef PRODUCT
2007 // ------------------------------------------------------------------
2008 // ciTypeFlow::LocalSet::print_on
2009 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2010   st->print("{");
2011   for (int i = 0; i < max; i++) {
2012     if (test(i)) st->print(" %d", i);
2013   }
2014   if (limit > max) {
2015     st->print(" %d..%d ", max, limit);
2016   }
2017   st->print(" }");
2018 }
2019 #endif
2020 
2021 // ciTypeFlow
2022 //
2023 // This is a pass over the bytecodes which computes the following:
2024 //   basic block structure
2025 //   interpreter type-states (a la the verifier)
2026 
2027 // ------------------------------------------------------------------
2028 // ciTypeFlow::ciTypeFlow
2029 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2030   _env = env;
2031   _method = method;
2032   _methodBlocks = method->get_method_blocks();
2033   _max_locals = method->max_locals();
2034   _max_stack = method->max_stack();
2035   _code_size = method->code_size();
2036   _has_irreducible_entry = false;
2037   _osr_bci = osr_bci;
2038   _failure_reason = NULL;
2039   assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2040   _work_list = NULL;
2041 
2042   _ciblock_count = _methodBlocks->num_blocks();
2043   _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
2044   for (int i = 0; i < _ciblock_count; i++) {
2045     _idx_to_blocklist[i] = NULL;
2046   }
2047   _block_map = NULL;  // until all blocks are seen
2048   _jsr_count = 0;
2049   _jsr_records = NULL;
2050 }
2051 
2052 // ------------------------------------------------------------------
2053 // ciTypeFlow::work_list_next
2054 //
2055 // Get the next basic block from our work list.
2056 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2057   assert(!work_list_empty(), "work list must not be empty");
2058   Block* next_block = _work_list;
2059   _work_list = next_block->next();
2060   next_block->set_next(NULL);
2061   next_block->set_on_work_list(false);
2062   return next_block;
2063 }
2064 
2065 // ------------------------------------------------------------------
2066 // ciTypeFlow::add_to_work_list
2067 //
2068 // Add a basic block to our work list.
2069 // List is sorted by decreasing postorder sort (same as increasing RPO)
2070 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2071   assert(!block->is_on_work_list(), "must not already be on work list");
2072 
2073   if (CITraceTypeFlow) {
2074     tty->print(">> Adding block ");
2075     block->print_value_on(tty);
2076     tty->print_cr(" to the work list : ");
2077   }
2078 
2079   block->set_on_work_list(true);
2080 
2081   // decreasing post order sort
2082 
2083   Block* prev = NULL;
2084   Block* current = _work_list;
2085   int po = block->post_order();
2086   while (current != NULL) {
2087     if (!current->has_post_order() || po > current->post_order())
2088       break;
2089     prev = current;
2090     current = current->next();
2091   }
2092   if (prev == NULL) {
2093     block->set_next(_work_list);
2094     _work_list = block;
2095   } else {
2096     block->set_next(current);
2097     prev->set_next(block);
2098   }
2099 
2100   if (CITraceTypeFlow) {
2101     tty->cr();
2102   }
2103 }
2104 
2105 // ------------------------------------------------------------------
2106 // ciTypeFlow::block_at
2107 //
2108 // Return the block beginning at bci which has a JsrSet compatible
2109 // with jsrs.
2110 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2111   // First find the right ciBlock.
2112   if (CITraceTypeFlow) {
2113     tty->print(">> Requesting block for %d/", bci);
2114     jsrs->print_on(tty);
2115     tty->cr();
2116   }
2117 
2118   ciBlock* ciblk = _methodBlocks->block_containing(bci);
2119   assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2120   Block* block = get_block_for(ciblk->index(), jsrs, option);
2121 
2122   assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2123 
2124   if (CITraceTypeFlow) {
2125     if (block != NULL) {
2126       tty->print(">> Found block ");
2127       block->print_value_on(tty);
2128       tty->cr();
2129     } else {
2130       tty->print_cr(">> No such block.");
2131     }
2132   }
2133 
2134   return block;
2135 }
2136 
2137 // ------------------------------------------------------------------
2138 // ciTypeFlow::make_jsr_record
2139 //
2140 // Make a JsrRecord for a given (entry, return) pair, if such a record
2141 // does not already exist.
2142 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2143                                                    int return_address) {
2144   if (_jsr_records == NULL) {
2145     _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2146                                                            _jsr_count,
2147                                                            0,
2148                                                            NULL);
2149   }
2150   JsrRecord* record = NULL;
2151   int len = _jsr_records->length();
2152   for (int i = 0; i < len; i++) {
2153     JsrRecord* record = _jsr_records->at(i);
2154     if (record->entry_address() == entry_address &&
2155         record->return_address() == return_address) {
2156       return record;
2157     }
2158   }
2159 
2160   record = new (arena()) JsrRecord(entry_address, return_address);
2161   _jsr_records->append(record);
2162   return record;
2163 }
2164 
2165 // ------------------------------------------------------------------
2166 // ciTypeFlow::flow_exceptions
2167 //
2168 // Merge the current state into all exceptional successors at the
2169 // current point in the code.
2170 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2171                                  GrowableArray<ciInstanceKlass*>* exc_klasses,
2172                                  ciTypeFlow::StateVector* state) {
2173   int len = exceptions->length();
2174   assert(exc_klasses->length() == len, "must have same length");
2175   for (int i = 0; i < len; i++) {
2176     Block* block = exceptions->at(i);
2177     ciInstanceKlass* exception_klass = exc_klasses->at(i);
2178 
2179     if (!exception_klass->is_loaded()) {
2180       // Do not compile any code for unloaded exception types.
2181       // Following compiler passes are responsible for doing this also.
2182       continue;
2183     }
2184 
2185     if (block->meet_exception(exception_klass, state)) {
2186       // Block was modified and has PO.  Add it to the work list.
2187       if (block->has_post_order() &&
2188           !block->is_on_work_list()) {
2189         add_to_work_list(block);
2190       }
2191     }
2192   }
2193 }
2194 
2195 // ------------------------------------------------------------------
2196 // ciTypeFlow::flow_successors
2197 //
2198 // Merge the current state into all successors at the current point
2199 // in the code.
2200 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2201                                  ciTypeFlow::StateVector* state) {
2202   int len = successors->length();
2203   for (int i = 0; i < len; i++) {
2204     Block* block = successors->at(i);
2205     if (block->meet(state)) {
2206       // Block was modified and has PO.  Add it to the work list.
2207       if (block->has_post_order() &&
2208           !block->is_on_work_list()) {
2209         add_to_work_list(block);
2210       }
2211     }
2212   }
2213 }
2214 
2215 // ------------------------------------------------------------------
2216 // ciTypeFlow::can_trap
2217 //
2218 // Tells if a given instruction is able to generate an exception edge.
2219 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2220   // Cf. GenerateOopMap::do_exception_edge.
2221   if (!Bytecodes::can_trap(str.cur_bc()))  return false;
2222 
2223   switch (str.cur_bc()) {
2224     // %%% FIXME: ldc of Class can generate an exception
2225     case Bytecodes::_ldc:
2226     case Bytecodes::_ldc_w:
2227     case Bytecodes::_ldc2_w:
2228     case Bytecodes::_aload_0:
2229       // These bytecodes can trap for rewriting.  We need to assume that
2230       // they do not throw exceptions to make the monitor analysis work.
2231       return false;
2232 
2233     case Bytecodes::_ireturn:
2234     case Bytecodes::_lreturn:
2235     case Bytecodes::_freturn:
2236     case Bytecodes::_dreturn:
2237     case Bytecodes::_areturn:
2238     case Bytecodes::_vreturn:
2239     case Bytecodes::_return:
2240       // We can assume the monitor stack is empty in this analysis.
2241       return false;
2242 
2243     case Bytecodes::_monitorexit:
2244       // We can assume monitors are matched in this analysis.
2245       return false;
2246   }
2247 
2248   return true;
2249 }
2250 
2251 // ------------------------------------------------------------------
2252 // ciTypeFlow::clone_loop_heads
2253 //
2254 // Clone the loop heads
2255 bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2256   bool rslt = false;
2257   for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2258     lp = iter.current();
2259     Block* head = lp->head();
2260     if (lp == loop_tree_root() ||
2261         lp->is_irreducible() ||
2262         !head->is_clonable_exit(lp))
2263       continue;
2264 
2265     // Avoid BoxLock merge.
2266     if (EliminateNestedLocks && head->has_monitorenter())
2267       continue;
2268 
2269     // check not already cloned
2270     if (head->backedge_copy_count() != 0)
2271       continue;
2272 
2273     // Don't clone head of OSR loop to get correct types in start block.
2274     if (is_osr_flow() && head->start() == start_bci())
2275       continue;
2276 
2277     // check _no_ shared head below us
2278     Loop* ch;
2279     for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2280     if (ch != NULL)
2281       continue;
2282 
2283     // Clone head
2284     Block* new_head = head->looping_succ(lp);
2285     Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2286     // Update lp's info
2287     clone->set_loop(lp);
2288     lp->set_head(new_head);
2289     lp->set_tail(clone);
2290     // And move original head into outer loop
2291     head->set_loop(lp->parent());
2292 
2293     rslt = true;
2294   }
2295   return rslt;
2296 }
2297 
2298 // ------------------------------------------------------------------
2299 // ciTypeFlow::clone_loop_head
2300 //
2301 // Clone lp's head and replace tail's successors with clone.
2302 //
2303 //  |
2304 //  v
2305 // head <-> body
2306 //  |
2307 //  v
2308 // exit
2309 //
2310 // new_head
2311 //
2312 //  |
2313 //  v
2314 // head ----------\
2315 //  |             |
2316 //  |             v
2317 //  |  clone <-> body
2318 //  |    |
2319 //  | /--/
2320 //  | |
2321 //  v v
2322 // exit
2323 //
2324 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2325   Block* head = lp->head();
2326   Block* tail = lp->tail();
2327   if (CITraceTypeFlow) {
2328     tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2329     tty->print("  for predecessor ");                tail->print_value_on(tty);
2330     tty->cr();
2331   }
2332   Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2333   assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2334 
2335   assert(!clone->has_pre_order(), "just created");
2336   clone->set_next_pre_order();
2337 
2338   // Insert clone after (orig) tail in reverse post order
2339   clone->set_rpo_next(tail->rpo_next());
2340   tail->set_rpo_next(clone);
2341 
2342   // tail->head becomes tail->clone
2343   for (SuccIter iter(tail); !iter.done(); iter.next()) {
2344     if (iter.succ() == head) {
2345       iter.set_succ(clone);
2346       // Update predecessor information
2347       head->predecessors()->remove(tail);
2348       clone->predecessors()->append(tail);
2349     }
2350   }
2351   flow_block(tail, temp_vector, temp_set);
2352   if (head == tail) {
2353     // For self-loops, clone->head becomes clone->clone
2354     flow_block(clone, temp_vector, temp_set);
2355     for (SuccIter iter(clone); !iter.done(); iter.next()) {
2356       if (iter.succ() == head) {
2357         iter.set_succ(clone);
2358         // Update predecessor information
2359         head->predecessors()->remove(clone);
2360         clone->predecessors()->append(clone);
2361         break;
2362       }
2363     }
2364   }
2365   flow_block(clone, temp_vector, temp_set);
2366 
2367   return clone;
2368 }
2369 
2370 // ------------------------------------------------------------------
2371 // ciTypeFlow::flow_block
2372 //
2373 // Interpret the effects of the bytecodes on the incoming state
2374 // vector of a basic block.  Push the changed state to succeeding
2375 // basic blocks.
2376 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2377                             ciTypeFlow::StateVector* state,
2378                             ciTypeFlow::JsrSet* jsrs) {
2379   if (CITraceTypeFlow) {
2380     tty->print("\n>> ANALYZING BLOCK : ");
2381     tty->cr();
2382     block->print_on(tty);
2383   }
2384   assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2385 
2386   int start = block->start();
2387   int limit = block->limit();
2388   int control = block->control();
2389   if (control != ciBlock::fall_through_bci) {
2390     limit = control;
2391   }
2392 
2393   // Grab the state from the current block.
2394   block->copy_state_into(state);
2395   state->def_locals()->clear();
2396 
2397   GrowableArray<Block*>*           exceptions = block->exceptions();
2398   GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2399   bool has_exceptions = exceptions->length() > 0;
2400 
2401   bool exceptions_used = false;
2402 
2403   ciBytecodeStream str(method());
2404   str.reset_to_bci(start);
2405   Bytecodes::Code code;
2406   while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2407          str.cur_bci() < limit) {
2408     // Check for exceptional control flow from this point.
2409     if (has_exceptions && can_trap(str)) {
2410       flow_exceptions(exceptions, exc_klasses, state);
2411       exceptions_used = true;
2412     }
2413     // Apply the effects of the current bytecode to our state.
2414     bool res = state->apply_one_bytecode(&str);
2415 
2416     // Watch for bailouts.
2417     if (failing())  return;
2418 
2419     if (str.cur_bc() == Bytecodes::_monitorenter) {
2420       block->set_has_monitorenter();
2421     }
2422 
2423     if (res) {
2424 
2425       // We have encountered a trap.  Record it in this block.
2426       block->set_trap(state->trap_bci(), state->trap_index());
2427 
2428       if (CITraceTypeFlow) {
2429         tty->print_cr(">> Found trap");
2430         block->print_on(tty);
2431       }
2432 
2433       // Save set of locals defined in this block
2434       block->def_locals()->add(state->def_locals());
2435 
2436       // Record (no) successors.
2437       block->successors(&str, state, jsrs);
2438 
2439       assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2440 
2441       // Discontinue interpretation of this Block.
2442       return;
2443     }
2444   }
2445 
2446   GrowableArray<Block*>* successors = NULL;
2447   if (control != ciBlock::fall_through_bci) {
2448     // Check for exceptional control flow from this point.
2449     if (has_exceptions && can_trap(str)) {
2450       flow_exceptions(exceptions, exc_klasses, state);
2451       exceptions_used = true;
2452     }
2453 
2454     // Fix the JsrSet to reflect effect of the bytecode.
2455     block->copy_jsrs_into(jsrs);
2456     jsrs->apply_control(this, &str, state);
2457 
2458     // Find successor edges based on old state and new JsrSet.
2459     successors = block->successors(&str, state, jsrs);
2460 
2461     // Apply the control changes to the state.
2462     state->apply_one_bytecode(&str);
2463   } else {
2464     // Fall through control
2465     successors = block->successors(&str, NULL, NULL);
2466   }
2467 
2468   // Save set of locals defined in this block
2469   block->def_locals()->add(state->def_locals());
2470 
2471   // Remove untaken exception paths
2472   if (!exceptions_used)
2473     exceptions->clear();
2474 
2475   // Pass our state to successors.
2476   flow_successors(successors, state);
2477 }
2478 
2479 // ------------------------------------------------------------------
2480 // ciTypeFlow::PostOrderLoops::next
2481 //
2482 // Advance to next loop tree using a postorder, left-to-right traversal.
2483 void ciTypeFlow::PostorderLoops::next() {
2484   assert(!done(), "must not be done.");
2485   if (_current->sibling() != NULL) {
2486     _current = _current->sibling();
2487     while (_current->child() != NULL) {
2488       _current = _current->child();
2489     }
2490   } else {
2491     _current = _current->parent();
2492   }
2493 }
2494 
2495 // ------------------------------------------------------------------
2496 // ciTypeFlow::PreOrderLoops::next
2497 //
2498 // Advance to next loop tree using a preorder, left-to-right traversal.
2499 void ciTypeFlow::PreorderLoops::next() {
2500   assert(!done(), "must not be done.");
2501   if (_current->child() != NULL) {
2502     _current = _current->child();
2503   } else if (_current->sibling() != NULL) {
2504     _current = _current->sibling();
2505   } else {
2506     while (_current != _root && _current->sibling() == NULL) {
2507       _current = _current->parent();
2508     }
2509     if (_current == _root) {
2510       _current = NULL;
2511       assert(done(), "must be done.");
2512     } else {
2513       assert(_current->sibling() != NULL, "must be more to do");
2514       _current = _current->sibling();
2515     }
2516   }
2517 }
2518 
2519 // ------------------------------------------------------------------
2520 // ciTypeFlow::Loop::sorted_merge
2521 //
2522 // Merge the branch lp into this branch, sorting on the loop head
2523 // pre_orders. Returns the leaf of the merged branch.
2524 // Child and sibling pointers will be setup later.
2525 // Sort is (looking from leaf towards the root)
2526 //  descending on primary key: loop head's pre_order, and
2527 //  ascending  on secondary key: loop tail's pre_order.
2528 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2529   Loop* leaf = this;
2530   Loop* prev = NULL;
2531   Loop* current = leaf;
2532   while (lp != NULL) {
2533     int lp_pre_order = lp->head()->pre_order();
2534     // Find insertion point for "lp"
2535     while (current != NULL) {
2536       if (current == lp)
2537         return leaf; // Already in list
2538       if (current->head()->pre_order() < lp_pre_order)
2539         break;
2540       if (current->head()->pre_order() == lp_pre_order &&
2541           current->tail()->pre_order() > lp->tail()->pre_order()) {
2542         break;
2543       }
2544       prev = current;
2545       current = current->parent();
2546     }
2547     Loop* next_lp = lp->parent(); // Save future list of items to insert
2548     // Insert lp before current
2549     lp->set_parent(current);
2550     if (prev != NULL) {
2551       prev->set_parent(lp);
2552     } else {
2553       leaf = lp;
2554     }
2555     prev = lp;     // Inserted item is new prev[ious]
2556     lp = next_lp;  // Next item to insert
2557   }
2558   return leaf;
2559 }
2560 
2561 // ------------------------------------------------------------------
2562 // ciTypeFlow::build_loop_tree
2563 //
2564 // Incrementally build loop tree.
2565 void ciTypeFlow::build_loop_tree(Block* blk) {
2566   assert(!blk->is_post_visited(), "precondition");
2567   Loop* innermost = NULL; // merge of loop tree branches over all successors
2568 
2569   for (SuccIter iter(blk); !iter.done(); iter.next()) {
2570     Loop*  lp   = NULL;
2571     Block* succ = iter.succ();
2572     if (!succ->is_post_visited()) {
2573       // Found backedge since predecessor post visited, but successor is not
2574       assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2575 
2576       // Create a LoopNode to mark this loop.
2577       lp = new (arena()) Loop(succ, blk);
2578       if (succ->loop() == NULL)
2579         succ->set_loop(lp);
2580       // succ->loop will be updated to innermost loop on a later call, when blk==succ
2581 
2582     } else {  // Nested loop
2583       lp = succ->loop();
2584 
2585       // If succ is loop head, find outer loop.
2586       while (lp != NULL && lp->head() == succ) {
2587         lp = lp->parent();
2588       }
2589       if (lp == NULL) {
2590         // Infinite loop, it's parent is the root
2591         lp = loop_tree_root();
2592       }
2593     }
2594 
2595     // Check for irreducible loop.
2596     // Successor has already been visited. If the successor's loop head
2597     // has already been post-visited, then this is another entry into the loop.
2598     while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2599       _has_irreducible_entry = true;
2600       lp->set_irreducible(succ);
2601       if (!succ->is_on_work_list()) {
2602         // Assume irreducible entries need more data flow
2603         add_to_work_list(succ);
2604       }
2605       Loop* plp = lp->parent();
2606       if (plp == NULL) {
2607         // This only happens for some irreducible cases.  The parent
2608         // will be updated during a later pass.
2609         break;
2610       }
2611       lp = plp;
2612     }
2613 
2614     // Merge loop tree branch for all successors.
2615     innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2616 
2617   } // end loop
2618 
2619   if (innermost == NULL) {
2620     assert(blk->successors()->length() == 0, "CFG exit");
2621     blk->set_loop(loop_tree_root());
2622   } else if (innermost->head() == blk) {
2623     // If loop header, complete the tree pointers
2624     if (blk->loop() != innermost) {
2625 #ifdef ASSERT
2626       assert(blk->loop()->head() == innermost->head(), "same head");
2627       Loop* dl;
2628       for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2629       assert(dl == blk->loop(), "blk->loop() already in innermost list");
2630 #endif
2631       blk->set_loop(innermost);
2632     }
2633     innermost->def_locals()->add(blk->def_locals());
2634     Loop* l = innermost;
2635     Loop* p = l->parent();
2636     while (p && l->head() == blk) {
2637       l->set_sibling(p->child());  // Put self on parents 'next child'
2638       p->set_child(l);             // Make self the first child of parent
2639       p->def_locals()->add(l->def_locals());
2640       l = p;                       // Walk up the parent chain
2641       p = l->parent();
2642     }
2643   } else {
2644     blk->set_loop(innermost);
2645     innermost->def_locals()->add(blk->def_locals());
2646   }
2647 }
2648 
2649 // ------------------------------------------------------------------
2650 // ciTypeFlow::Loop::contains
2651 //
2652 // Returns true if lp is nested loop.
2653 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2654   assert(lp != NULL, "");
2655   if (this == lp || head() == lp->head()) return true;
2656   int depth1 = depth();
2657   int depth2 = lp->depth();
2658   if (depth1 > depth2)
2659     return false;
2660   while (depth1 < depth2) {
2661     depth2--;
2662     lp = lp->parent();
2663   }
2664   return this == lp;
2665 }
2666 
2667 // ------------------------------------------------------------------
2668 // ciTypeFlow::Loop::depth
2669 //
2670 // Loop depth
2671 int ciTypeFlow::Loop::depth() const {
2672   int dp = 0;
2673   for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2674     dp++;
2675   return dp;
2676 }
2677 
2678 #ifndef PRODUCT
2679 // ------------------------------------------------------------------
2680 // ciTypeFlow::Loop::print
2681 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2682   for (int i = 0; i < indent; i++) st->print(" ");
2683   st->print("%d<-%d %s",
2684             is_root() ? 0 : this->head()->pre_order(),
2685             is_root() ? 0 : this->tail()->pre_order(),
2686             is_irreducible()?" irr":"");
2687   st->print(" defs: ");
2688   def_locals()->print_on(st, _head->outer()->method()->max_locals());
2689   st->cr();
2690   for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2691     ch->print(st, indent+2);
2692 }
2693 #endif
2694 
2695 // ------------------------------------------------------------------
2696 // ciTypeFlow::df_flow_types
2697 //
2698 // Perform the depth first type flow analysis. Helper for flow_types.
2699 void ciTypeFlow::df_flow_types(Block* start,
2700                                bool do_flow,
2701                                StateVector* temp_vector,
2702                                JsrSet* temp_set) {
2703   int dft_len = 100;
2704   GrowableArray<Block*> stk(dft_len);
2705 
2706   ciBlock* dummy = _methodBlocks->make_dummy_block();
2707   JsrSet* root_set = new JsrSet(NULL, 0);
2708   Block* root_head = new (arena()) Block(this, dummy, root_set);
2709   Block* root_tail = new (arena()) Block(this, dummy, root_set);
2710   root_head->set_pre_order(0);
2711   root_head->set_post_order(0);
2712   root_tail->set_pre_order(max_jint);
2713   root_tail->set_post_order(max_jint);
2714   set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2715 
2716   stk.push(start);
2717 
2718   _next_pre_order = 0;  // initialize pre_order counter
2719   _rpo_list = NULL;
2720   int next_po = 0;      // initialize post_order counter
2721 
2722   // Compute RPO and the control flow graph
2723   int size;
2724   while ((size = stk.length()) > 0) {
2725     Block* blk = stk.top(); // Leave node on stack
2726     if (!blk->is_visited()) {
2727       // forward arc in graph
2728       assert (!blk->has_pre_order(), "");
2729       blk->set_next_pre_order();
2730 
2731       if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2732         // Too many basic blocks.  Bail out.
2733         // This can happen when try/finally constructs are nested to depth N,
2734         // and there is O(2**N) cloning of jsr bodies.  See bug 4697245!
2735         // "MaxNodeLimit / 2" is used because probably the parser will
2736         // generate at least twice that many nodes and bail out.
2737         record_failure("too many basic blocks");
2738         return;
2739       }
2740       if (do_flow) {
2741         flow_block(blk, temp_vector, temp_set);
2742         if (failing()) return; // Watch for bailouts.
2743       }
2744     } else if (!blk->is_post_visited()) {
2745       // cross or back arc
2746       for (SuccIter iter(blk); !iter.done(); iter.next()) {
2747         Block* succ = iter.succ();
2748         if (!succ->is_visited()) {
2749           stk.push(succ);
2750         }
2751       }
2752       if (stk.length() == size) {
2753         // There were no additional children, post visit node now
2754         stk.pop(); // Remove node from stack
2755 
2756         build_loop_tree(blk);
2757         blk->set_post_order(next_po++);   // Assign post order
2758         prepend_to_rpo_list(blk);
2759         assert(blk->is_post_visited(), "");
2760 
2761         if (blk->is_loop_head() && !blk->is_on_work_list()) {
2762           // Assume loop heads need more data flow
2763           add_to_work_list(blk);
2764         }
2765       }
2766     } else {
2767       stk.pop(); // Remove post-visited node from stack
2768     }
2769   }
2770 }
2771 
2772 // ------------------------------------------------------------------
2773 // ciTypeFlow::flow_types
2774 //
2775 // Perform the type flow analysis, creating and cloning Blocks as
2776 // necessary.
2777 void ciTypeFlow::flow_types() {
2778   ResourceMark rm;
2779   StateVector* temp_vector = new StateVector(this);
2780   JsrSet* temp_set = new JsrSet(NULL, 16);
2781 
2782   // Create the method entry block.
2783   Block* start = block_at(start_bci(), temp_set);
2784 
2785   // Load the initial state into it.
2786   const StateVector* start_state = get_start_state();
2787   if (failing())  return;
2788   start->meet(start_state);
2789 
2790   // Depth first visit
2791   df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2792 
2793   if (failing())  return;
2794   assert(_rpo_list == start, "must be start");
2795 
2796   // Any loops found?
2797   if (loop_tree_root()->child() != NULL &&
2798       env()->comp_level() >= CompLevel_full_optimization) {
2799       // Loop optimizations are not performed on Tier1 compiles.
2800 
2801     bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2802 
2803     // If some loop heads were cloned, recompute postorder and loop tree
2804     if (changed) {
2805       loop_tree_root()->set_child(NULL);
2806       for (Block* blk = _rpo_list; blk != NULL;) {
2807         Block* next = blk->rpo_next();
2808         blk->df_init();
2809         blk = next;
2810       }
2811       df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2812     }
2813   }
2814 
2815   if (CITraceTypeFlow) {
2816     tty->print_cr("\nLoop tree");
2817     loop_tree_root()->print();
2818   }
2819 
2820   // Continue flow analysis until fixed point reached
2821 
2822   debug_only(int max_block = _next_pre_order;)
2823 
2824   while (!work_list_empty()) {
2825     Block* blk = work_list_next();
2826     assert (blk->has_post_order(), "post order assigned above");
2827 
2828     flow_block(blk, temp_vector, temp_set);
2829 
2830     assert (max_block == _next_pre_order, "no new blocks");
2831     assert (!failing(), "no more bailouts");
2832   }
2833 }
2834 
2835 // ------------------------------------------------------------------
2836 // ciTypeFlow::map_blocks
2837 //
2838 // Create the block map, which indexes blocks in reverse post-order.
2839 void ciTypeFlow::map_blocks() {
2840   assert(_block_map == NULL, "single initialization");
2841   int block_ct = _next_pre_order;
2842   _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2843   assert(block_ct == block_count(), "");
2844 
2845   Block* blk = _rpo_list;
2846   for (int m = 0; m < block_ct; m++) {
2847     int rpo = blk->rpo();
2848     assert(rpo == m, "should be sequential");
2849     _block_map[rpo] = blk;
2850     blk = blk->rpo_next();
2851   }
2852   assert(blk == NULL, "should be done");
2853 
2854   for (int j = 0; j < block_ct; j++) {
2855     assert(_block_map[j] != NULL, "must not drop any blocks");
2856     Block* block = _block_map[j];
2857     // Remove dead blocks from successor lists:
2858     for (int e = 0; e <= 1; e++) {
2859       GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2860       for (int k = 0; k < l->length(); k++) {
2861         Block* s = l->at(k);
2862         if (!s->has_post_order()) {
2863           if (CITraceTypeFlow) {
2864             tty->print("Removing dead %s successor of #%d: ", (e? "exceptional":  "normal"), block->pre_order());
2865             s->print_value_on(tty);
2866             tty->cr();
2867           }
2868           l->remove(s);
2869           --k;
2870         }
2871       }
2872     }
2873   }
2874 }
2875 
2876 // ------------------------------------------------------------------
2877 // ciTypeFlow::get_block_for
2878 //
2879 // Find a block with this ciBlock which has a compatible JsrSet.
2880 // If no such block exists, create it, unless the option is no_create.
2881 // If the option is create_backedge_copy, always create a fresh backedge copy.
2882 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2883   Arena* a = arena();
2884   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2885   if (blocks == NULL) {
2886     // Query only?
2887     if (option == no_create)  return NULL;
2888 
2889     // Allocate the growable array.
2890     blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2891     _idx_to_blocklist[ciBlockIndex] = blocks;
2892   }
2893 
2894   if (option != create_backedge_copy) {
2895     int len = blocks->length();
2896     for (int i = 0; i < len; i++) {
2897       Block* block = blocks->at(i);
2898       if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2899         return block;
2900       }
2901     }
2902   }
2903 
2904   // Query only?
2905   if (option == no_create)  return NULL;
2906 
2907   // We did not find a compatible block.  Create one.
2908   Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2909   if (option == create_backedge_copy)  new_block->set_backedge_copy(true);
2910   blocks->append(new_block);
2911   return new_block;
2912 }
2913 
2914 // ------------------------------------------------------------------
2915 // ciTypeFlow::backedge_copy_count
2916 //
2917 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2918   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2919 
2920   if (blocks == NULL) {
2921     return 0;
2922   }
2923 
2924   int count = 0;
2925   int len = blocks->length();
2926   for (int i = 0; i < len; i++) {
2927     Block* block = blocks->at(i);
2928     if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2929       count++;
2930     }
2931   }
2932 
2933   return count;
2934 }
2935 
2936 // ------------------------------------------------------------------
2937 // ciTypeFlow::do_flow
2938 //
2939 // Perform type inference flow analysis.
2940 void ciTypeFlow::do_flow() {
2941   if (CITraceTypeFlow) {
2942     tty->print_cr("\nPerforming flow analysis on method");
2943     method()->print();
2944     if (is_osr_flow())  tty->print(" at OSR bci %d", start_bci());
2945     tty->cr();
2946     method()->print_codes();
2947   }
2948   if (CITraceTypeFlow) {
2949     tty->print_cr("Initial CI Blocks");
2950     print_on(tty);
2951   }
2952   flow_types();
2953   // Watch for bailouts.
2954   if (failing()) {
2955     return;
2956   }
2957 
2958   map_blocks();
2959 
2960   if (CIPrintTypeFlow || CITraceTypeFlow) {
2961     rpo_print_on(tty);
2962   }
2963 }
2964 
2965 // ------------------------------------------------------------------
2966 // ciTypeFlow::is_dominated_by
2967 //
2968 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
2969 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
2970   assert(!method()->has_jsrs(), "jsrs are not supported");
2971 
2972   ResourceMark rm;
2973   JsrSet* jsrs = new ciTypeFlow::JsrSet(NULL);
2974   int        index = _methodBlocks->block_containing(bci)->index();
2975   int    dom_index = _methodBlocks->block_containing(dom_bci)->index();
2976   Block*     block = get_block_for(index, jsrs, ciTypeFlow::no_create);
2977   Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
2978 
2979   // Start block dominates all other blocks
2980   if (start_block()->rpo() == dom_block->rpo()) {
2981     return true;
2982   }
2983 
2984   // Dominated[i] is true if block i is dominated by dom_block
2985   int num_blocks = block_count();
2986   bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
2987   for (int i = 0; i < num_blocks; ++i) {
2988     dominated[i] = true;
2989   }
2990   dominated[start_block()->rpo()] = false;
2991 
2992   // Iterative dominator algorithm
2993   bool changed = true;
2994   while (changed) {
2995     changed = false;
2996     // Use reverse postorder iteration
2997     for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
2998       if (blk->is_start()) {
2999         // Ignore start block
3000         continue;
3001       }
3002       // The block is dominated if it is the dominating block
3003       // itself or if all predecessors are dominated.
3004       int index = blk->rpo();
3005       bool dom = (index == dom_block->rpo());
3006       if (!dom) {
3007         // Check if all predecessors are dominated
3008         dom = true;
3009         for (int i = 0; i < blk->predecessors()->length(); ++i) {
3010           Block* pred = blk->predecessors()->at(i);
3011           if (!dominated[pred->rpo()]) {
3012             dom = false;
3013             break;
3014           }
3015         }
3016       }
3017       // Update dominator information
3018       if (dominated[index] != dom) {
3019         changed = true;
3020         dominated[index] = dom;
3021       }
3022     }
3023   }
3024   // block dominated by dom_block?
3025   return dominated[block->rpo()];
3026 }
3027 
3028 // ------------------------------------------------------------------
3029 // ciTypeFlow::record_failure()
3030 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3031 // This is required because there is not a 1-1 relation between the ciEnv and
3032 // the TypeFlow passes within a compilation task.  For example, if the compiler
3033 // is considering inlining a method, it will request a TypeFlow.  If that fails,
3034 // the compilation as a whole may continue without the inlining.  Some TypeFlow
3035 // requests are not optional; if they fail the requestor is responsible for
3036 // copying the failure reason up to the ciEnv.  (See Parse::Parse.)
3037 void ciTypeFlow::record_failure(const char* reason) {
3038   if (env()->log() != NULL) {
3039     env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3040   }
3041   if (_failure_reason == NULL) {
3042     // Record the first failure reason.
3043     _failure_reason = reason;
3044   }
3045 }
3046 
3047 #ifndef PRODUCT
3048 // ------------------------------------------------------------------
3049 // ciTypeFlow::print_on
3050 void ciTypeFlow::print_on(outputStream* st) const {
3051   // Walk through CI blocks
3052   st->print_cr("********************************************************");
3053   st->print   ("TypeFlow for ");
3054   method()->name()->print_symbol_on(st);
3055   int limit_bci = code_size();
3056   st->print_cr("  %d bytes", limit_bci);
3057   ciMethodBlocks  *mblks = _methodBlocks;
3058   ciBlock* current = NULL;
3059   for (int bci = 0; bci < limit_bci; bci++) {
3060     ciBlock* blk = mblks->block_containing(bci);
3061     if (blk != NULL && blk != current) {
3062       current = blk;
3063       current->print_on(st);
3064 
3065       GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3066       int num_blocks = (blocks == NULL) ? 0 : blocks->length();
3067 
3068       if (num_blocks == 0) {
3069         st->print_cr("  No Blocks");
3070       } else {
3071         for (int i = 0; i < num_blocks; i++) {
3072           Block* block = blocks->at(i);
3073           block->print_on(st);
3074         }
3075       }
3076       st->print_cr("--------------------------------------------------------");
3077       st->cr();
3078     }
3079   }
3080   st->print_cr("********************************************************");
3081   st->cr();
3082 }
3083 
3084 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3085   st->print_cr("********************************************************");
3086   st->print   ("TypeFlow for ");
3087   method()->name()->print_symbol_on(st);
3088   int limit_bci = code_size();
3089   st->print_cr("  %d bytes", limit_bci);
3090   for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3091     blk->print_on(st);
3092     st->print_cr("--------------------------------------------------------");
3093     st->cr();
3094   }
3095   st->print_cr("********************************************************");
3096   st->cr();
3097 }
3098 #endif
--- EOF ---