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_aload
 551 void ciTypeFlow::StateVector::do_aload(ciBytecodeStream* str) {
 552   pop_int();
 553   ciArrayKlass* array_klass = pop_objOrValueArray();
 554   if (array_klass == NULL) {
 555     // Did aload 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::_vaload:
 910   case Bytecodes::_aaload: do_aload(str);                           break;
 911 
 912   case Bytecodes::_vastore:
 913   case Bytecodes::_aastore:
 914     {
 915       pop_object();
 916       pop_int();
 917       pop_objOrValueArray();
 918       break;
 919     }
 920   case Bytecodes::_aconst_null:
 921     {
 922       push_null();
 923       break;
 924     }
 925   case Bytecodes::_vload:
 926   case Bytecodes::_aload:   load_local_object(str->get_index());    break;
 927   case Bytecodes::_aload_0: load_local_object(0);                   break;
 928   case Bytecodes::_aload_1: load_local_object(1);                   break;
 929   case Bytecodes::_aload_2: load_local_object(2);                   break;
 930   case Bytecodes::_aload_3: load_local_object(3);                   break;
 931 
 932   case Bytecodes::_anewarray:
 933     {
 934       pop_int();
 935       bool will_link;
 936       ciKlass* element_klass = str->get_klass(will_link);
 937       if (!will_link) {
 938         trap(str, element_klass, str->get_klass_index());
 939       } else {
 940         push_object(ciArrayKlass::make(element_klass));
 941       }
 942       break;
 943     }
 944   case Bytecodes::_areturn:
 945   case Bytecodes::_vreturn:
 946   case Bytecodes::_ifnonnull:
 947   case Bytecodes::_ifnull:
 948     {
 949       pop_object();
 950       break;
 951     }
 952   case Bytecodes::_monitorenter:
 953     {
 954       pop_object();
 955       set_monitor_count(monitor_count() + 1);
 956       break;
 957     }
 958   case Bytecodes::_monitorexit:
 959     {
 960       pop_object();
 961       assert(monitor_count() > 0, "must be a monitor to exit from");
 962       set_monitor_count(monitor_count() - 1);
 963       break;
 964     }
 965   case Bytecodes::_arraylength:
 966     {
 967       pop_array();
 968       push_int();
 969       break;
 970     }
 971   case Bytecodes::_vstore:
 972   case Bytecodes::_astore:   store_local_object(str->get_index());  break;
 973   case Bytecodes::_astore_0: store_local_object(0);                 break;
 974   case Bytecodes::_astore_1: store_local_object(1);                 break;
 975   case Bytecodes::_astore_2: store_local_object(2);                 break;
 976   case Bytecodes::_astore_3: store_local_object(3);                 break;
 977 
 978   case Bytecodes::_athrow:
 979     {
 980       NEEDS_CLEANUP;
 981       pop_object();
 982       break;
 983     }
 984   case Bytecodes::_baload:
 985   case Bytecodes::_caload:
 986   case Bytecodes::_iaload:
 987   case Bytecodes::_saload:
 988     {
 989       pop_int();
 990       ciTypeArrayKlass* array_klass = pop_typeArray();
 991       // Put assert here for right type?
 992       push_int();
 993       break;
 994     }
 995   case Bytecodes::_bastore:
 996   case Bytecodes::_castore:
 997   case Bytecodes::_iastore:
 998   case Bytecodes::_sastore:
 999     {
1000       pop_int();
1001       pop_int();
1002       pop_typeArray();
1003       // assert here?
1004       break;
1005     }
1006   case Bytecodes::_bipush:
1007   case Bytecodes::_iconst_m1:
1008   case Bytecodes::_iconst_0:
1009   case Bytecodes::_iconst_1:
1010   case Bytecodes::_iconst_2:
1011   case Bytecodes::_iconst_3:
1012   case Bytecodes::_iconst_4:
1013   case Bytecodes::_iconst_5:
1014   case Bytecodes::_sipush:
1015     {
1016       push_int();
1017       break;
1018     }
1019   case Bytecodes::_checkcast: do_checkcast(str);                  break;
1020 
1021   case Bytecodes::_d2f:
1022     {
1023       pop_double();
1024       push_float();
1025       break;
1026     }
1027   case Bytecodes::_d2i:
1028     {
1029       pop_double();
1030       push_int();
1031       break;
1032     }
1033   case Bytecodes::_d2l:
1034     {
1035       pop_double();
1036       push_long();
1037       break;
1038     }
1039   case Bytecodes::_dadd:
1040   case Bytecodes::_ddiv:
1041   case Bytecodes::_dmul:
1042   case Bytecodes::_drem:
1043   case Bytecodes::_dsub:
1044     {
1045       pop_double();
1046       pop_double();
1047       push_double();
1048       break;
1049     }
1050   case Bytecodes::_daload:
1051     {
1052       pop_int();
1053       ciTypeArrayKlass* array_klass = pop_typeArray();
1054       // Put assert here for right type?
1055       push_double();
1056       break;
1057     }
1058   case Bytecodes::_dastore:
1059     {
1060       pop_double();
1061       pop_int();
1062       pop_typeArray();
1063       // assert here?
1064       break;
1065     }
1066   case Bytecodes::_dcmpg:
1067   case Bytecodes::_dcmpl:
1068     {
1069       pop_double();
1070       pop_double();
1071       push_int();
1072       break;
1073     }
1074   case Bytecodes::_dconst_0:
1075   case Bytecodes::_dconst_1:
1076     {
1077       push_double();
1078       break;
1079     }
1080   case Bytecodes::_dload:   load_local_double(str->get_index());    break;
1081   case Bytecodes::_dload_0: load_local_double(0);                   break;
1082   case Bytecodes::_dload_1: load_local_double(1);                   break;
1083   case Bytecodes::_dload_2: load_local_double(2);                   break;
1084   case Bytecodes::_dload_3: load_local_double(3);                   break;
1085 
1086   case Bytecodes::_dneg:
1087     {
1088       pop_double();
1089       push_double();
1090       break;
1091     }
1092   case Bytecodes::_dreturn:
1093     {
1094       pop_double();
1095       break;
1096     }
1097   case Bytecodes::_dstore:   store_local_double(str->get_index());  break;
1098   case Bytecodes::_dstore_0: store_local_double(0);                 break;
1099   case Bytecodes::_dstore_1: store_local_double(1);                 break;
1100   case Bytecodes::_dstore_2: store_local_double(2);                 break;
1101   case Bytecodes::_dstore_3: store_local_double(3);                 break;
1102 
1103   case Bytecodes::_dup:
1104     {
1105       push(type_at_tos());
1106       break;
1107     }
1108   case Bytecodes::_dup_x1:
1109     {
1110       ciType* value1 = pop_value();
1111       ciType* value2 = pop_value();
1112       push(value1);
1113       push(value2);
1114       push(value1);
1115       break;
1116     }
1117   case Bytecodes::_dup_x2:
1118     {
1119       ciType* value1 = pop_value();
1120       ciType* value2 = pop_value();
1121       ciType* value3 = pop_value();
1122       push(value1);
1123       push(value3);
1124       push(value2);
1125       push(value1);
1126       break;
1127     }
1128   case Bytecodes::_dup2:
1129     {
1130       ciType* value1 = pop_value();
1131       ciType* value2 = pop_value();
1132       push(value2);
1133       push(value1);
1134       push(value2);
1135       push(value1);
1136       break;
1137     }
1138   case Bytecodes::_dup2_x1:
1139     {
1140       ciType* value1 = pop_value();
1141       ciType* value2 = pop_value();
1142       ciType* value3 = pop_value();
1143       push(value2);
1144       push(value1);
1145       push(value3);
1146       push(value2);
1147       push(value1);
1148       break;
1149     }
1150   case Bytecodes::_dup2_x2:
1151     {
1152       ciType* value1 = pop_value();
1153       ciType* value2 = pop_value();
1154       ciType* value3 = pop_value();
1155       ciType* value4 = pop_value();
1156       push(value2);
1157       push(value1);
1158       push(value4);
1159       push(value3);
1160       push(value2);
1161       push(value1);
1162       break;
1163     }
1164   case Bytecodes::_f2d:
1165     {
1166       pop_float();
1167       push_double();
1168       break;
1169     }
1170   case Bytecodes::_f2i:
1171     {
1172       pop_float();
1173       push_int();
1174       break;
1175     }
1176   case Bytecodes::_f2l:
1177     {
1178       pop_float();
1179       push_long();
1180       break;
1181     }
1182   case Bytecodes::_fadd:
1183   case Bytecodes::_fdiv:
1184   case Bytecodes::_fmul:
1185   case Bytecodes::_frem:
1186   case Bytecodes::_fsub:
1187     {
1188       pop_float();
1189       pop_float();
1190       push_float();
1191       break;
1192     }
1193   case Bytecodes::_faload:
1194     {
1195       pop_int();
1196       ciTypeArrayKlass* array_klass = pop_typeArray();
1197       // Put assert here.
1198       push_float();
1199       break;
1200     }
1201   case Bytecodes::_fastore:
1202     {
1203       pop_float();
1204       pop_int();
1205       ciTypeArrayKlass* array_klass = pop_typeArray();
1206       // Put assert here.
1207       break;
1208     }
1209   case Bytecodes::_fcmpg:
1210   case Bytecodes::_fcmpl:
1211     {
1212       pop_float();
1213       pop_float();
1214       push_int();
1215       break;
1216     }
1217   case Bytecodes::_fconst_0:
1218   case Bytecodes::_fconst_1:
1219   case Bytecodes::_fconst_2:
1220     {
1221       push_float();
1222       break;
1223     }
1224   case Bytecodes::_fload:   load_local_float(str->get_index());     break;
1225   case Bytecodes::_fload_0: load_local_float(0);                    break;
1226   case Bytecodes::_fload_1: load_local_float(1);                    break;
1227   case Bytecodes::_fload_2: load_local_float(2);                    break;
1228   case Bytecodes::_fload_3: load_local_float(3);                    break;
1229 
1230   case Bytecodes::_fneg:
1231     {
1232       pop_float();
1233       push_float();
1234       break;
1235     }
1236   case Bytecodes::_freturn:
1237     {
1238       pop_float();
1239       break;
1240     }
1241   case Bytecodes::_fstore:    store_local_float(str->get_index());   break;
1242   case Bytecodes::_fstore_0:  store_local_float(0);                  break;
1243   case Bytecodes::_fstore_1:  store_local_float(1);                  break;
1244   case Bytecodes::_fstore_2:  store_local_float(2);                  break;
1245   case Bytecodes::_fstore_3:  store_local_float(3);                  break;
1246 
1247   case Bytecodes::_vgetfield:
1248   case Bytecodes::_getfield:  do_getfield(str);                      break;
1249   case Bytecodes::_getstatic: do_getstatic(str);                     break;
1250 
1251   case Bytecodes::_goto:
1252   case Bytecodes::_goto_w:
1253   case Bytecodes::_nop:
1254   case Bytecodes::_return:
1255     {
1256       // do nothing.
1257       break;
1258     }
1259   case Bytecodes::_i2b:
1260   case Bytecodes::_i2c:
1261   case Bytecodes::_i2s:
1262   case Bytecodes::_ineg:
1263     {
1264       pop_int();
1265       push_int();
1266       break;
1267     }
1268   case Bytecodes::_i2d:
1269     {
1270       pop_int();
1271       push_double();
1272       break;
1273     }
1274   case Bytecodes::_i2f:
1275     {
1276       pop_int();
1277       push_float();
1278       break;
1279     }
1280   case Bytecodes::_i2l:
1281     {
1282       pop_int();
1283       push_long();
1284       break;
1285     }
1286   case Bytecodes::_iadd:
1287   case Bytecodes::_iand:
1288   case Bytecodes::_idiv:
1289   case Bytecodes::_imul:
1290   case Bytecodes::_ior:
1291   case Bytecodes::_irem:
1292   case Bytecodes::_ishl:
1293   case Bytecodes::_ishr:
1294   case Bytecodes::_isub:
1295   case Bytecodes::_iushr:
1296   case Bytecodes::_ixor:
1297     {
1298       pop_int();
1299       pop_int();
1300       push_int();
1301       break;
1302     }
1303   case Bytecodes::_if_acmpeq:
1304   case Bytecodes::_if_acmpne:
1305     {
1306       pop_object();
1307       pop_object();
1308       break;
1309     }
1310   case Bytecodes::_if_icmpeq:
1311   case Bytecodes::_if_icmpge:
1312   case Bytecodes::_if_icmpgt:
1313   case Bytecodes::_if_icmple:
1314   case Bytecodes::_if_icmplt:
1315   case Bytecodes::_if_icmpne:
1316     {
1317       pop_int();
1318       pop_int();
1319       break;
1320     }
1321   case Bytecodes::_ifeq:
1322   case Bytecodes::_ifle:
1323   case Bytecodes::_iflt:
1324   case Bytecodes::_ifge:
1325   case Bytecodes::_ifgt:
1326   case Bytecodes::_ifne:
1327   case Bytecodes::_ireturn:
1328   case Bytecodes::_lookupswitch:
1329   case Bytecodes::_tableswitch:
1330     {
1331       pop_int();
1332       break;
1333     }
1334   case Bytecodes::_iinc:
1335     {
1336       int lnum = str->get_index();
1337       check_int(local(lnum));
1338       store_to_local(lnum);
1339       break;
1340     }
1341   case Bytecodes::_iload:   load_local_int(str->get_index()); break;
1342   case Bytecodes::_iload_0: load_local_int(0);                      break;
1343   case Bytecodes::_iload_1: load_local_int(1);                      break;
1344   case Bytecodes::_iload_2: load_local_int(2);                      break;
1345   case Bytecodes::_iload_3: load_local_int(3);                      break;
1346 
1347   case Bytecodes::_instanceof:
1348     {
1349       // Check for uncommon trap:
1350       do_checkcast(str);
1351       pop_object();
1352       push_int();
1353       break;
1354     }
1355   case Bytecodes::_invokeinterface: do_invoke(str, true);           break;
1356   case Bytecodes::_invokespecial:   do_invoke(str, true);           break;
1357   case Bytecodes::_invokestatic:    do_invoke(str, false);          break;
1358   case Bytecodes::_invokedirect:
1359   case Bytecodes::_invokevirtual:   do_invoke(str, true);           break;
1360   case Bytecodes::_invokedynamic:   do_invoke(str, false);          break;
1361 
1362   case Bytecodes::_istore:   store_local_int(str->get_index());     break;
1363   case Bytecodes::_istore_0: store_local_int(0);                    break;
1364   case Bytecodes::_istore_1: store_local_int(1);                    break;
1365   case Bytecodes::_istore_2: store_local_int(2);                    break;
1366   case Bytecodes::_istore_3: store_local_int(3);                    break;
1367 
1368   case Bytecodes::_jsr:
1369   case Bytecodes::_jsr_w: do_jsr(str);                              break;
1370 
1371   case Bytecodes::_l2d:
1372     {
1373       pop_long();
1374       push_double();
1375       break;
1376     }
1377   case Bytecodes::_l2f:
1378     {
1379       pop_long();
1380       push_float();
1381       break;
1382     }
1383   case Bytecodes::_l2i:
1384     {
1385       pop_long();
1386       push_int();
1387       break;
1388     }
1389   case Bytecodes::_ladd:
1390   case Bytecodes::_land:
1391   case Bytecodes::_ldiv:
1392   case Bytecodes::_lmul:
1393   case Bytecodes::_lor:
1394   case Bytecodes::_lrem:
1395   case Bytecodes::_lsub:
1396   case Bytecodes::_lxor:
1397     {
1398       pop_long();
1399       pop_long();
1400       push_long();
1401       break;
1402     }
1403   case Bytecodes::_laload:
1404     {
1405       pop_int();
1406       ciTypeArrayKlass* array_klass = pop_typeArray();
1407       // Put assert here for right type?
1408       push_long();
1409       break;
1410     }
1411   case Bytecodes::_lastore:
1412     {
1413       pop_long();
1414       pop_int();
1415       pop_typeArray();
1416       // assert here?
1417       break;
1418     }
1419   case Bytecodes::_lcmp:
1420     {
1421       pop_long();
1422       pop_long();
1423       push_int();
1424       break;
1425     }
1426   case Bytecodes::_lconst_0:
1427   case Bytecodes::_lconst_1:
1428     {
1429       push_long();
1430       break;
1431     }
1432   case Bytecodes::_ldc:
1433   case Bytecodes::_ldc_w:
1434   case Bytecodes::_ldc2_w:
1435     {
1436       do_ldc(str);
1437       break;
1438     }
1439 
1440   case Bytecodes::_lload:   load_local_long(str->get_index());      break;
1441   case Bytecodes::_lload_0: load_local_long(0);                     break;
1442   case Bytecodes::_lload_1: load_local_long(1);                     break;
1443   case Bytecodes::_lload_2: load_local_long(2);                     break;
1444   case Bytecodes::_lload_3: load_local_long(3);                     break;
1445 
1446   case Bytecodes::_lneg:
1447     {
1448       pop_long();
1449       push_long();
1450       break;
1451     }
1452   case Bytecodes::_lreturn:
1453     {
1454       pop_long();
1455       break;
1456     }
1457   case Bytecodes::_lshl:
1458   case Bytecodes::_lshr:
1459   case Bytecodes::_lushr:
1460     {
1461       pop_int();
1462       pop_long();
1463       push_long();
1464       break;
1465     }
1466   case Bytecodes::_lstore:   store_local_long(str->get_index());    break;
1467   case Bytecodes::_lstore_0: store_local_long(0);                   break;
1468   case Bytecodes::_lstore_1: store_local_long(1);                   break;
1469   case Bytecodes::_lstore_2: store_local_long(2);                   break;
1470   case Bytecodes::_lstore_3: store_local_long(3);                   break;
1471 
1472   case Bytecodes::_multianewarray: do_multianewarray(str);          break;
1473   case Bytecodes::_new:      do_new(str);                           break;
1474   case Bytecodes::_vnew:     do_vnew(str);                          break;
1475 
1476   case Bytecodes::_newarray: do_newarray(str);                      break;
1477 
1478   case Bytecodes::_pop:
1479     {
1480       pop();
1481       break;
1482     }
1483   case Bytecodes::_pop2:
1484     {
1485       pop();
1486       pop();
1487       break;
1488     }
1489 
1490   case Bytecodes::_putfield:       do_putfield(str);                 break;
1491   case Bytecodes::_putstatic:      do_putstatic(str);                break;
1492 
1493   case Bytecodes::_ret: do_ret(str);                                 break;
1494 
1495   case Bytecodes::_swap:
1496     {
1497       ciType* value1 = pop_value();
1498       ciType* value2 = pop_value();
1499       push(value1);
1500       push(value2);
1501       break;
1502     }
1503   case Bytecodes::_vunbox:
1504   {
1505     do_vunbox(str);
1506     break;
1507   }
1508   case Bytecodes::_vbox:
1509   {
1510     do_vbox(str);
1511     break;
1512   }
1513   case Bytecodes::_wide:
1514   default:
1515     {
1516       // The iterator should skip this.
1517       ShouldNotReachHere();
1518       break;
1519     }
1520   }
1521 
1522   if (CITraceTypeFlow) {
1523     print_on(tty);
1524   }
1525 
1526   return (_trap_bci != -1);
1527 }
1528 
1529 #ifndef PRODUCT
1530 // ------------------------------------------------------------------
1531 // ciTypeFlow::StateVector::print_cell_on
1532 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1533   ciType* type = type_at(c);
1534   if (type == top_type()) {
1535     st->print("top");
1536   } else if (type == bottom_type()) {
1537     st->print("bottom");
1538   } else if (type == null_type()) {
1539     st->print("null");
1540   } else if (type == long2_type()) {
1541     st->print("long2");
1542   } else if (type == double2_type()) {
1543     st->print("double2");
1544   } else if (is_int(type)) {
1545     st->print("int");
1546   } else if (is_long(type)) {
1547     st->print("long");
1548   } else if (is_float(type)) {
1549     st->print("float");
1550   } else if (is_double(type)) {
1551     st->print("double");
1552   } else if (type->is_return_address()) {
1553     st->print("address(%d)", type->as_return_address()->bci());
1554   } else {
1555     if (type->is_klass()) {
1556       type->as_klass()->name()->print_symbol_on(st);
1557     } else {
1558       st->print("UNEXPECTED TYPE");
1559       type->print();
1560     }
1561   }
1562 }
1563 
1564 // ------------------------------------------------------------------
1565 // ciTypeFlow::StateVector::print_on
1566 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1567   int num_locals   = _outer->max_locals();
1568   int num_stack    = stack_size();
1569   int num_monitors = monitor_count();
1570   st->print_cr("  State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1571   if (num_stack >= 0) {
1572     int i;
1573     for (i = 0; i < num_locals; i++) {
1574       st->print("    local %2d : ", i);
1575       print_cell_on(st, local(i));
1576       st->cr();
1577     }
1578     for (i = 0; i < num_stack; i++) {
1579       st->print("    stack %2d : ", i);
1580       print_cell_on(st, stack(i));
1581       st->cr();
1582     }
1583   }
1584 }
1585 #endif
1586 
1587 
1588 // ------------------------------------------------------------------
1589 // ciTypeFlow::SuccIter::next
1590 //
1591 void ciTypeFlow::SuccIter::next() {
1592   int succ_ct = _pred->successors()->length();
1593   int next = _index + 1;
1594   if (next < succ_ct) {
1595     _index = next;
1596     _succ = _pred->successors()->at(next);
1597     return;
1598   }
1599   for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1600     // Do not compile any code for unloaded exception types.
1601     // Following compiler passes are responsible for doing this also.
1602     ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1603     if (exception_klass->is_loaded()) {
1604       _index = next;
1605       _succ = _pred->exceptions()->at(i);
1606       return;
1607     }
1608     next++;
1609   }
1610   _index = -1;
1611   _succ = NULL;
1612 }
1613 
1614 // ------------------------------------------------------------------
1615 // ciTypeFlow::SuccIter::set_succ
1616 //
1617 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1618   int succ_ct = _pred->successors()->length();
1619   if (_index < succ_ct) {
1620     _pred->successors()->at_put(_index, succ);
1621   } else {
1622     int idx = _index - succ_ct;
1623     _pred->exceptions()->at_put(idx, succ);
1624   }
1625 }
1626 
1627 // ciTypeFlow::Block
1628 //
1629 // A basic block.
1630 
1631 // ------------------------------------------------------------------
1632 // ciTypeFlow::Block::Block
1633 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1634                          ciBlock *ciblk,
1635                          ciTypeFlow::JsrSet* jsrs) {
1636   _ciblock = ciblk;
1637   _exceptions = NULL;
1638   _exc_klasses = NULL;
1639   _successors = NULL;
1640   _predecessors = new (outer->arena()) GrowableArray<Block*>(outer->arena(), 1, 0, NULL);
1641   _state = new (outer->arena()) StateVector(outer);
1642   JsrSet* new_jsrs =
1643     new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1644   jsrs->copy_into(new_jsrs);
1645   _jsrs = new_jsrs;
1646   _next = NULL;
1647   _on_work_list = false;
1648   _backedge_copy = false;
1649   _has_monitorenter = false;
1650   _trap_bci = -1;
1651   _trap_index = 0;
1652   df_init();
1653 
1654   if (CITraceTypeFlow) {
1655     tty->print_cr(">> Created new block");
1656     print_on(tty);
1657   }
1658 
1659   assert(this->outer() == outer, "outer link set up");
1660   assert(!outer->have_block_count(), "must not have mapped blocks yet");
1661 }
1662 
1663 // ------------------------------------------------------------------
1664 // ciTypeFlow::Block::df_init
1665 void ciTypeFlow::Block::df_init() {
1666   _pre_order = -1; assert(!has_pre_order(), "");
1667   _post_order = -1; assert(!has_post_order(), "");
1668   _loop = NULL;
1669   _irreducible_entry = false;
1670   _rpo_next = NULL;
1671 }
1672 
1673 // ------------------------------------------------------------------
1674 // ciTypeFlow::Block::successors
1675 //
1676 // Get the successors for this Block.
1677 GrowableArray<ciTypeFlow::Block*>*
1678 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1679                               ciTypeFlow::StateVector* state,
1680                               ciTypeFlow::JsrSet* jsrs) {
1681   if (_successors == NULL) {
1682     if (CITraceTypeFlow) {
1683       tty->print(">> Computing successors for block ");
1684       print_value_on(tty);
1685       tty->cr();
1686     }
1687 
1688     ciTypeFlow* analyzer = outer();
1689     Arena* arena = analyzer->arena();
1690     Block* block = NULL;
1691     bool has_successor = !has_trap() &&
1692                          (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1693     if (!has_successor) {
1694       _successors =
1695         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1696       // No successors
1697     } else if (control() == ciBlock::fall_through_bci) {
1698       assert(str->cur_bci() == limit(), "bad block end");
1699       // This block simply falls through to the next.
1700       _successors =
1701         new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1702 
1703       Block* block = analyzer->block_at(limit(), _jsrs);
1704       assert(_successors->length() == FALL_THROUGH, "");
1705       _successors->append(block);
1706     } else {
1707       int current_bci = str->cur_bci();
1708       int next_bci = str->next_bci();
1709       int branch_bci = -1;
1710       Block* target = NULL;
1711       assert(str->next_bci() == limit(), "bad block end");
1712       // This block is not a simple fall-though.  Interpret
1713       // the current bytecode to find our successors.
1714       switch (str->cur_bc()) {
1715       case Bytecodes::_ifeq:         case Bytecodes::_ifne:
1716       case Bytecodes::_iflt:         case Bytecodes::_ifge:
1717       case Bytecodes::_ifgt:         case Bytecodes::_ifle:
1718       case Bytecodes::_if_icmpeq:    case Bytecodes::_if_icmpne:
1719       case Bytecodes::_if_icmplt:    case Bytecodes::_if_icmpge:
1720       case Bytecodes::_if_icmpgt:    case Bytecodes::_if_icmple:
1721       case Bytecodes::_if_acmpeq:    case Bytecodes::_if_acmpne:
1722       case Bytecodes::_ifnull:       case Bytecodes::_ifnonnull:
1723         // Our successors are the branch target and the next bci.
1724         branch_bci = str->get_dest();
1725         _successors =
1726           new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1727         assert(_successors->length() == IF_NOT_TAKEN, "");
1728         _successors->append(analyzer->block_at(next_bci, jsrs));
1729         assert(_successors->length() == IF_TAKEN, "");
1730         _successors->append(analyzer->block_at(branch_bci, jsrs));
1731         break;
1732 
1733       case Bytecodes::_goto:
1734         branch_bci = str->get_dest();
1735         _successors =
1736           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1737         assert(_successors->length() == GOTO_TARGET, "");
1738         _successors->append(analyzer->block_at(branch_bci, jsrs));
1739         break;
1740 
1741       case Bytecodes::_jsr:
1742         branch_bci = str->get_dest();
1743         _successors =
1744           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1745         assert(_successors->length() == GOTO_TARGET, "");
1746         _successors->append(analyzer->block_at(branch_bci, jsrs));
1747         break;
1748 
1749       case Bytecodes::_goto_w:
1750       case Bytecodes::_jsr_w:
1751         _successors =
1752           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1753         assert(_successors->length() == GOTO_TARGET, "");
1754         _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1755         break;
1756 
1757       case Bytecodes::_tableswitch:  {
1758         Bytecode_tableswitch tableswitch(str);
1759 
1760         int len = tableswitch.length();
1761         _successors =
1762           new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1763         int bci = current_bci + tableswitch.default_offset();
1764         Block* block = analyzer->block_at(bci, jsrs);
1765         assert(_successors->length() == SWITCH_DEFAULT, "");
1766         _successors->append(block);
1767         while (--len >= 0) {
1768           int bci = current_bci + tableswitch.dest_offset_at(len);
1769           block = analyzer->block_at(bci, jsrs);
1770           assert(_successors->length() >= SWITCH_CASES, "");
1771           _successors->append_if_missing(block);
1772         }
1773         break;
1774       }
1775 
1776       case Bytecodes::_lookupswitch: {
1777         Bytecode_lookupswitch lookupswitch(str);
1778 
1779         int npairs = lookupswitch.number_of_pairs();
1780         _successors =
1781           new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1782         int bci = current_bci + lookupswitch.default_offset();
1783         Block* block = analyzer->block_at(bci, jsrs);
1784         assert(_successors->length() == SWITCH_DEFAULT, "");
1785         _successors->append(block);
1786         while(--npairs >= 0) {
1787           LookupswitchPair pair = lookupswitch.pair_at(npairs);
1788           int bci = current_bci + pair.offset();
1789           Block* block = analyzer->block_at(bci, jsrs);
1790           assert(_successors->length() >= SWITCH_CASES, "");
1791           _successors->append_if_missing(block);
1792         }
1793         break;
1794       }
1795 
1796       case Bytecodes::_athrow:
1797       case Bytecodes::_ireturn:
1798       case Bytecodes::_lreturn:
1799       case Bytecodes::_freturn:
1800       case Bytecodes::_dreturn:
1801       case Bytecodes::_areturn:
1802       case Bytecodes::_vreturn:
1803       case Bytecodes::_return:
1804         _successors =
1805           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1806         // No successors
1807         break;
1808 
1809       case Bytecodes::_ret: {
1810         _successors =
1811           new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1812 
1813         Cell local = state->local(str->get_index());
1814         ciType* return_address = state->type_at(local);
1815         assert(return_address->is_return_address(), "verify: wrong type");
1816         int bci = return_address->as_return_address()->bci();
1817         assert(_successors->length() == GOTO_TARGET, "");
1818         _successors->append(analyzer->block_at(bci, jsrs));
1819         break;
1820       }
1821 
1822       case Bytecodes::_wide:
1823       default:
1824         ShouldNotReachHere();
1825         break;
1826       }
1827     }
1828 
1829     // Set predecessor information
1830     for (int i = 0; i < _successors->length(); i++) {
1831       Block* block = _successors->at(i);
1832       block->predecessors()->append(this);
1833     }
1834   }
1835   return _successors;
1836 }
1837 
1838 // ------------------------------------------------------------------
1839 // ciTypeFlow::Block:compute_exceptions
1840 //
1841 // Compute the exceptional successors and types for this Block.
1842 void ciTypeFlow::Block::compute_exceptions() {
1843   assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1844 
1845   if (CITraceTypeFlow) {
1846     tty->print(">> Computing exceptions for block ");
1847     print_value_on(tty);
1848     tty->cr();
1849   }
1850 
1851   ciTypeFlow* analyzer = outer();
1852   Arena* arena = analyzer->arena();
1853 
1854   // Any bci in the block will do.
1855   ciExceptionHandlerStream str(analyzer->method(), start());
1856 
1857   // Allocate our growable arrays.
1858   int exc_count = str.count();
1859   _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1860   _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1861                                                              0, NULL);
1862 
1863   for ( ; !str.is_done(); str.next()) {
1864     ciExceptionHandler* handler = str.handler();
1865     int bci = handler->handler_bci();
1866     ciInstanceKlass* klass = NULL;
1867     if (bci == -1) {
1868       // There is no catch all.  It is possible to exit the method.
1869       break;
1870     }
1871     if (handler->is_catch_all()) {
1872       klass = analyzer->env()->Throwable_klass();
1873     } else {
1874       klass = handler->catch_klass();
1875     }
1876     Block* block = analyzer->block_at(bci, _jsrs);
1877     _exceptions->append(block);
1878     block->predecessors()->append(this);
1879     _exc_klasses->append(klass);
1880   }
1881 }
1882 
1883 // ------------------------------------------------------------------
1884 // ciTypeFlow::Block::set_backedge_copy
1885 // Use this only to make a pre-existing public block into a backedge copy.
1886 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1887   assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1888   _backedge_copy = z;
1889 }
1890 
1891 // ------------------------------------------------------------------
1892 // ciTypeFlow::Block::is_clonable_exit
1893 //
1894 // At most 2 normal successors, one of which continues looping,
1895 // and all exceptional successors must exit.
1896 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1897   int normal_cnt  = 0;
1898   int in_loop_cnt = 0;
1899   for (SuccIter iter(this); !iter.done(); iter.next()) {
1900     Block* succ = iter.succ();
1901     if (iter.is_normal_ctrl()) {
1902       if (++normal_cnt > 2) return false;
1903       if (lp->contains(succ->loop())) {
1904         if (++in_loop_cnt > 1) return false;
1905       }
1906     } else {
1907       if (lp->contains(succ->loop())) return false;
1908     }
1909   }
1910   return in_loop_cnt == 1;
1911 }
1912 
1913 // ------------------------------------------------------------------
1914 // ciTypeFlow::Block::looping_succ
1915 //
1916 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1917   assert(successors()->length() <= 2, "at most 2 normal successors");
1918   for (SuccIter iter(this); !iter.done(); iter.next()) {
1919     Block* succ = iter.succ();
1920     if (lp->contains(succ->loop())) {
1921       return succ;
1922     }
1923   }
1924   return NULL;
1925 }
1926 
1927 #ifndef PRODUCT
1928 // ------------------------------------------------------------------
1929 // ciTypeFlow::Block::print_value_on
1930 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1931   if (has_pre_order()) st->print("#%-2d ", pre_order());
1932   if (has_rpo())       st->print("rpo#%-2d ", rpo());
1933   st->print("[%d - %d)", start(), limit());
1934   if (is_loop_head()) st->print(" lphd");
1935   if (is_irreducible_entry()) st->print(" irred");
1936   if (_jsrs->size() > 0) { st->print("/");  _jsrs->print_on(st); }
1937   if (is_backedge_copy())  st->print("/backedge_copy");
1938 }
1939 
1940 // ------------------------------------------------------------------
1941 // ciTypeFlow::Block::print_on
1942 void ciTypeFlow::Block::print_on(outputStream* st) const {
1943   if ((Verbose || WizardMode) && (limit() >= 0)) {
1944     // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1945     outer()->method()->print_codes_on(start(), limit(), st);
1946   }
1947   st->print_cr("  ====================================================  ");
1948   st->print ("  ");
1949   print_value_on(st);
1950   st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1951   if (loop() && loop()->parent() != NULL) {
1952     st->print(" loops:");
1953     Loop* lp = loop();
1954     do {
1955       st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
1956       if (lp->is_irreducible()) st->print("(ir)");
1957       lp = lp->parent();
1958     } while (lp->parent() != NULL);
1959   }
1960   st->cr();
1961   _state->print_on(st);
1962   if (_successors == NULL) {
1963     st->print_cr("  No successor information");
1964   } else {
1965     int num_successors = _successors->length();
1966     st->print_cr("  Successors : %d", num_successors);
1967     for (int i = 0; i < num_successors; i++) {
1968       Block* successor = _successors->at(i);
1969       st->print("    ");
1970       successor->print_value_on(st);
1971       st->cr();
1972     }
1973   }
1974   if (_predecessors == NULL) {
1975     st->print_cr("  No predecessor information");
1976   } else {
1977     int num_predecessors = _predecessors->length();
1978     st->print_cr("  Predecessors : %d", num_predecessors);
1979     for (int i = 0; i < num_predecessors; i++) {
1980       Block* predecessor = _predecessors->at(i);
1981       st->print("    ");
1982       predecessor->print_value_on(st);
1983       st->cr();
1984     }
1985   }
1986   if (_exceptions == NULL) {
1987     st->print_cr("  No exception information");
1988   } else {
1989     int num_exceptions = _exceptions->length();
1990     st->print_cr("  Exceptions : %d", num_exceptions);
1991     for (int i = 0; i < num_exceptions; i++) {
1992       Block* exc_succ = _exceptions->at(i);
1993       ciInstanceKlass* exc_klass = _exc_klasses->at(i);
1994       st->print("    ");
1995       exc_succ->print_value_on(st);
1996       st->print(" -- ");
1997       exc_klass->name()->print_symbol_on(st);
1998       st->cr();
1999     }
2000   }
2001   if (has_trap()) {
2002     st->print_cr("  Traps on %d with trap index %d", trap_bci(), trap_index());
2003   }
2004   st->print_cr("  ====================================================  ");
2005 }
2006 #endif
2007 
2008 #ifndef PRODUCT
2009 // ------------------------------------------------------------------
2010 // ciTypeFlow::LocalSet::print_on
2011 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2012   st->print("{");
2013   for (int i = 0; i < max; i++) {
2014     if (test(i)) st->print(" %d", i);
2015   }
2016   if (limit > max) {
2017     st->print(" %d..%d ", max, limit);
2018   }
2019   st->print(" }");
2020 }
2021 #endif
2022 
2023 // ciTypeFlow
2024 //
2025 // This is a pass over the bytecodes which computes the following:
2026 //   basic block structure
2027 //   interpreter type-states (a la the verifier)
2028 
2029 // ------------------------------------------------------------------
2030 // ciTypeFlow::ciTypeFlow
2031 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2032   _env = env;
2033   _method = method;
2034   _methodBlocks = method->get_method_blocks();
2035   _max_locals = method->max_locals();
2036   _max_stack = method->max_stack();
2037   _code_size = method->code_size();
2038   _has_irreducible_entry = false;
2039   _osr_bci = osr_bci;
2040   _failure_reason = NULL;
2041   assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2042   _work_list = NULL;
2043 
2044   _ciblock_count = _methodBlocks->num_blocks();
2045   _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
2046   for (int i = 0; i < _ciblock_count; i++) {
2047     _idx_to_blocklist[i] = NULL;
2048   }
2049   _block_map = NULL;  // until all blocks are seen
2050   _jsr_count = 0;
2051   _jsr_records = NULL;
2052 }
2053 
2054 // ------------------------------------------------------------------
2055 // ciTypeFlow::work_list_next
2056 //
2057 // Get the next basic block from our work list.
2058 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2059   assert(!work_list_empty(), "work list must not be empty");
2060   Block* next_block = _work_list;
2061   _work_list = next_block->next();
2062   next_block->set_next(NULL);
2063   next_block->set_on_work_list(false);
2064   return next_block;
2065 }
2066 
2067 // ------------------------------------------------------------------
2068 // ciTypeFlow::add_to_work_list
2069 //
2070 // Add a basic block to our work list.
2071 // List is sorted by decreasing postorder sort (same as increasing RPO)
2072 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2073   assert(!block->is_on_work_list(), "must not already be on work list");
2074 
2075   if (CITraceTypeFlow) {
2076     tty->print(">> Adding block ");
2077     block->print_value_on(tty);
2078     tty->print_cr(" to the work list : ");
2079   }
2080 
2081   block->set_on_work_list(true);
2082 
2083   // decreasing post order sort
2084 
2085   Block* prev = NULL;
2086   Block* current = _work_list;
2087   int po = block->post_order();
2088   while (current != NULL) {
2089     if (!current->has_post_order() || po > current->post_order())
2090       break;
2091     prev = current;
2092     current = current->next();
2093   }
2094   if (prev == NULL) {
2095     block->set_next(_work_list);
2096     _work_list = block;
2097   } else {
2098     block->set_next(current);
2099     prev->set_next(block);
2100   }
2101 
2102   if (CITraceTypeFlow) {
2103     tty->cr();
2104   }
2105 }
2106 
2107 // ------------------------------------------------------------------
2108 // ciTypeFlow::block_at
2109 //
2110 // Return the block beginning at bci which has a JsrSet compatible
2111 // with jsrs.
2112 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2113   // First find the right ciBlock.
2114   if (CITraceTypeFlow) {
2115     tty->print(">> Requesting block for %d/", bci);
2116     jsrs->print_on(tty);
2117     tty->cr();
2118   }
2119 
2120   ciBlock* ciblk = _methodBlocks->block_containing(bci);
2121   assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2122   Block* block = get_block_for(ciblk->index(), jsrs, option);
2123 
2124   assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2125 
2126   if (CITraceTypeFlow) {
2127     if (block != NULL) {
2128       tty->print(">> Found block ");
2129       block->print_value_on(tty);
2130       tty->cr();
2131     } else {
2132       tty->print_cr(">> No such block.");
2133     }
2134   }
2135 
2136   return block;
2137 }
2138 
2139 // ------------------------------------------------------------------
2140 // ciTypeFlow::make_jsr_record
2141 //
2142 // Make a JsrRecord for a given (entry, return) pair, if such a record
2143 // does not already exist.
2144 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2145                                                    int return_address) {
2146   if (_jsr_records == NULL) {
2147     _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2148                                                            _jsr_count,
2149                                                            0,
2150                                                            NULL);
2151   }
2152   JsrRecord* record = NULL;
2153   int len = _jsr_records->length();
2154   for (int i = 0; i < len; i++) {
2155     JsrRecord* record = _jsr_records->at(i);
2156     if (record->entry_address() == entry_address &&
2157         record->return_address() == return_address) {
2158       return record;
2159     }
2160   }
2161 
2162   record = new (arena()) JsrRecord(entry_address, return_address);
2163   _jsr_records->append(record);
2164   return record;
2165 }
2166 
2167 // ------------------------------------------------------------------
2168 // ciTypeFlow::flow_exceptions
2169 //
2170 // Merge the current state into all exceptional successors at the
2171 // current point in the code.
2172 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2173                                  GrowableArray<ciInstanceKlass*>* exc_klasses,
2174                                  ciTypeFlow::StateVector* state) {
2175   int len = exceptions->length();
2176   assert(exc_klasses->length() == len, "must have same length");
2177   for (int i = 0; i < len; i++) {
2178     Block* block = exceptions->at(i);
2179     ciInstanceKlass* exception_klass = exc_klasses->at(i);
2180 
2181     if (!exception_klass->is_loaded()) {
2182       // Do not compile any code for unloaded exception types.
2183       // Following compiler passes are responsible for doing this also.
2184       continue;
2185     }
2186 
2187     if (block->meet_exception(exception_klass, state)) {
2188       // Block was modified and has PO.  Add it to the work list.
2189       if (block->has_post_order() &&
2190           !block->is_on_work_list()) {
2191         add_to_work_list(block);
2192       }
2193     }
2194   }
2195 }
2196 
2197 // ------------------------------------------------------------------
2198 // ciTypeFlow::flow_successors
2199 //
2200 // Merge the current state into all successors at the current point
2201 // in the code.
2202 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2203                                  ciTypeFlow::StateVector* state) {
2204   int len = successors->length();
2205   for (int i = 0; i < len; i++) {
2206     Block* block = successors->at(i);
2207     if (block->meet(state)) {
2208       // Block was modified and has PO.  Add it to the work list.
2209       if (block->has_post_order() &&
2210           !block->is_on_work_list()) {
2211         add_to_work_list(block);
2212       }
2213     }
2214   }
2215 }
2216 
2217 // ------------------------------------------------------------------
2218 // ciTypeFlow::can_trap
2219 //
2220 // Tells if a given instruction is able to generate an exception edge.
2221 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2222   // Cf. GenerateOopMap::do_exception_edge.
2223   if (!Bytecodes::can_trap(str.cur_bc()))  return false;
2224 
2225   switch (str.cur_bc()) {
2226     // %%% FIXME: ldc of Class can generate an exception
2227     case Bytecodes::_ldc:
2228     case Bytecodes::_ldc_w:
2229     case Bytecodes::_ldc2_w:
2230     case Bytecodes::_aload_0:
2231       // These bytecodes can trap for rewriting.  We need to assume that
2232       // they do not throw exceptions to make the monitor analysis work.
2233       return false;
2234 
2235     case Bytecodes::_ireturn:
2236     case Bytecodes::_lreturn:
2237     case Bytecodes::_freturn:
2238     case Bytecodes::_dreturn:
2239     case Bytecodes::_areturn:
2240     case Bytecodes::_vreturn:
2241     case Bytecodes::_return:
2242       // We can assume the monitor stack is empty in this analysis.
2243       return false;
2244 
2245     case Bytecodes::_monitorexit:
2246       // We can assume monitors are matched in this analysis.
2247       return false;
2248   }
2249 
2250   return true;
2251 }
2252 
2253 // ------------------------------------------------------------------
2254 // ciTypeFlow::clone_loop_heads
2255 //
2256 // Clone the loop heads
2257 bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2258   bool rslt = false;
2259   for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2260     lp = iter.current();
2261     Block* head = lp->head();
2262     if (lp == loop_tree_root() ||
2263         lp->is_irreducible() ||
2264         !head->is_clonable_exit(lp))
2265       continue;
2266 
2267     // Avoid BoxLock merge.
2268     if (EliminateNestedLocks && head->has_monitorenter())
2269       continue;
2270 
2271     // check not already cloned
2272     if (head->backedge_copy_count() != 0)
2273       continue;
2274 
2275     // Don't clone head of OSR loop to get correct types in start block.
2276     if (is_osr_flow() && head->start() == start_bci())
2277       continue;
2278 
2279     // check _no_ shared head below us
2280     Loop* ch;
2281     for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2282     if (ch != NULL)
2283       continue;
2284 
2285     // Clone head
2286     Block* new_head = head->looping_succ(lp);
2287     Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2288     // Update lp's info
2289     clone->set_loop(lp);
2290     lp->set_head(new_head);
2291     lp->set_tail(clone);
2292     // And move original head into outer loop
2293     head->set_loop(lp->parent());
2294 
2295     rslt = true;
2296   }
2297   return rslt;
2298 }
2299 
2300 // ------------------------------------------------------------------
2301 // ciTypeFlow::clone_loop_head
2302 //
2303 // Clone lp's head and replace tail's successors with clone.
2304 //
2305 //  |
2306 //  v
2307 // head <-> body
2308 //  |
2309 //  v
2310 // exit
2311 //
2312 // new_head
2313 //
2314 //  |
2315 //  v
2316 // head ----------\
2317 //  |             |
2318 //  |             v
2319 //  |  clone <-> body
2320 //  |    |
2321 //  | /--/
2322 //  | |
2323 //  v v
2324 // exit
2325 //
2326 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2327   Block* head = lp->head();
2328   Block* tail = lp->tail();
2329   if (CITraceTypeFlow) {
2330     tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2331     tty->print("  for predecessor ");                tail->print_value_on(tty);
2332     tty->cr();
2333   }
2334   Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2335   assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2336 
2337   assert(!clone->has_pre_order(), "just created");
2338   clone->set_next_pre_order();
2339 
2340   // Insert clone after (orig) tail in reverse post order
2341   clone->set_rpo_next(tail->rpo_next());
2342   tail->set_rpo_next(clone);
2343 
2344   // tail->head becomes tail->clone
2345   for (SuccIter iter(tail); !iter.done(); iter.next()) {
2346     if (iter.succ() == head) {
2347       iter.set_succ(clone);
2348       // Update predecessor information
2349       head->predecessors()->remove(tail);
2350       clone->predecessors()->append(tail);
2351     }
2352   }
2353   flow_block(tail, temp_vector, temp_set);
2354   if (head == tail) {
2355     // For self-loops, clone->head becomes clone->clone
2356     flow_block(clone, temp_vector, temp_set);
2357     for (SuccIter iter(clone); !iter.done(); iter.next()) {
2358       if (iter.succ() == head) {
2359         iter.set_succ(clone);
2360         // Update predecessor information
2361         head->predecessors()->remove(clone);
2362         clone->predecessors()->append(clone);
2363         break;
2364       }
2365     }
2366   }
2367   flow_block(clone, temp_vector, temp_set);
2368 
2369   return clone;
2370 }
2371 
2372 // ------------------------------------------------------------------
2373 // ciTypeFlow::flow_block
2374 //
2375 // Interpret the effects of the bytecodes on the incoming state
2376 // vector of a basic block.  Push the changed state to succeeding
2377 // basic blocks.
2378 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2379                             ciTypeFlow::StateVector* state,
2380                             ciTypeFlow::JsrSet* jsrs) {
2381   if (CITraceTypeFlow) {
2382     tty->print("\n>> ANALYZING BLOCK : ");
2383     tty->cr();
2384     block->print_on(tty);
2385   }
2386   assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2387 
2388   int start = block->start();
2389   int limit = block->limit();
2390   int control = block->control();
2391   if (control != ciBlock::fall_through_bci) {
2392     limit = control;
2393   }
2394 
2395   // Grab the state from the current block.
2396   block->copy_state_into(state);
2397   state->def_locals()->clear();
2398 
2399   GrowableArray<Block*>*           exceptions = block->exceptions();
2400   GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2401   bool has_exceptions = exceptions->length() > 0;
2402 
2403   bool exceptions_used = false;
2404 
2405   ciBytecodeStream str(method());
2406   str.reset_to_bci(start);
2407   Bytecodes::Code code;
2408   while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2409          str.cur_bci() < limit) {
2410     // Check for exceptional control flow from this point.
2411     if (has_exceptions && can_trap(str)) {
2412       flow_exceptions(exceptions, exc_klasses, state);
2413       exceptions_used = true;
2414     }
2415     // Apply the effects of the current bytecode to our state.
2416     bool res = state->apply_one_bytecode(&str);
2417 
2418     // Watch for bailouts.
2419     if (failing())  return;
2420 
2421     if (str.cur_bc() == Bytecodes::_monitorenter) {
2422       block->set_has_monitorenter();
2423     }
2424 
2425     if (res) {
2426 
2427       // We have encountered a trap.  Record it in this block.
2428       block->set_trap(state->trap_bci(), state->trap_index());
2429 
2430       if (CITraceTypeFlow) {
2431         tty->print_cr(">> Found trap");
2432         block->print_on(tty);
2433       }
2434 
2435       // Save set of locals defined in this block
2436       block->def_locals()->add(state->def_locals());
2437 
2438       // Record (no) successors.
2439       block->successors(&str, state, jsrs);
2440 
2441       assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2442 
2443       // Discontinue interpretation of this Block.
2444       return;
2445     }
2446   }
2447 
2448   GrowableArray<Block*>* successors = NULL;
2449   if (control != ciBlock::fall_through_bci) {
2450     // Check for exceptional control flow from this point.
2451     if (has_exceptions && can_trap(str)) {
2452       flow_exceptions(exceptions, exc_klasses, state);
2453       exceptions_used = true;
2454     }
2455 
2456     // Fix the JsrSet to reflect effect of the bytecode.
2457     block->copy_jsrs_into(jsrs);
2458     jsrs->apply_control(this, &str, state);
2459 
2460     // Find successor edges based on old state and new JsrSet.
2461     successors = block->successors(&str, state, jsrs);
2462 
2463     // Apply the control changes to the state.
2464     state->apply_one_bytecode(&str);
2465   } else {
2466     // Fall through control
2467     successors = block->successors(&str, NULL, NULL);
2468   }
2469 
2470   // Save set of locals defined in this block
2471   block->def_locals()->add(state->def_locals());
2472 
2473   // Remove untaken exception paths
2474   if (!exceptions_used)
2475     exceptions->clear();
2476 
2477   // Pass our state to successors.
2478   flow_successors(successors, state);
2479 }
2480 
2481 // ------------------------------------------------------------------
2482 // ciTypeFlow::PostOrderLoops::next
2483 //
2484 // Advance to next loop tree using a postorder, left-to-right traversal.
2485 void ciTypeFlow::PostorderLoops::next() {
2486   assert(!done(), "must not be done.");
2487   if (_current->sibling() != NULL) {
2488     _current = _current->sibling();
2489     while (_current->child() != NULL) {
2490       _current = _current->child();
2491     }
2492   } else {
2493     _current = _current->parent();
2494   }
2495 }
2496 
2497 // ------------------------------------------------------------------
2498 // ciTypeFlow::PreOrderLoops::next
2499 //
2500 // Advance to next loop tree using a preorder, left-to-right traversal.
2501 void ciTypeFlow::PreorderLoops::next() {
2502   assert(!done(), "must not be done.");
2503   if (_current->child() != NULL) {
2504     _current = _current->child();
2505   } else if (_current->sibling() != NULL) {
2506     _current = _current->sibling();
2507   } else {
2508     while (_current != _root && _current->sibling() == NULL) {
2509       _current = _current->parent();
2510     }
2511     if (_current == _root) {
2512       _current = NULL;
2513       assert(done(), "must be done.");
2514     } else {
2515       assert(_current->sibling() != NULL, "must be more to do");
2516       _current = _current->sibling();
2517     }
2518   }
2519 }
2520 
2521 // ------------------------------------------------------------------
2522 // ciTypeFlow::Loop::sorted_merge
2523 //
2524 // Merge the branch lp into this branch, sorting on the loop head
2525 // pre_orders. Returns the leaf of the merged branch.
2526 // Child and sibling pointers will be setup later.
2527 // Sort is (looking from leaf towards the root)
2528 //  descending on primary key: loop head's pre_order, and
2529 //  ascending  on secondary key: loop tail's pre_order.
2530 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2531   Loop* leaf = this;
2532   Loop* prev = NULL;
2533   Loop* current = leaf;
2534   while (lp != NULL) {
2535     int lp_pre_order = lp->head()->pre_order();
2536     // Find insertion point for "lp"
2537     while (current != NULL) {
2538       if (current == lp)
2539         return leaf; // Already in list
2540       if (current->head()->pre_order() < lp_pre_order)
2541         break;
2542       if (current->head()->pre_order() == lp_pre_order &&
2543           current->tail()->pre_order() > lp->tail()->pre_order()) {
2544         break;
2545       }
2546       prev = current;
2547       current = current->parent();
2548     }
2549     Loop* next_lp = lp->parent(); // Save future list of items to insert
2550     // Insert lp before current
2551     lp->set_parent(current);
2552     if (prev != NULL) {
2553       prev->set_parent(lp);
2554     } else {
2555       leaf = lp;
2556     }
2557     prev = lp;     // Inserted item is new prev[ious]
2558     lp = next_lp;  // Next item to insert
2559   }
2560   return leaf;
2561 }
2562 
2563 // ------------------------------------------------------------------
2564 // ciTypeFlow::build_loop_tree
2565 //
2566 // Incrementally build loop tree.
2567 void ciTypeFlow::build_loop_tree(Block* blk) {
2568   assert(!blk->is_post_visited(), "precondition");
2569   Loop* innermost = NULL; // merge of loop tree branches over all successors
2570 
2571   for (SuccIter iter(blk); !iter.done(); iter.next()) {
2572     Loop*  lp   = NULL;
2573     Block* succ = iter.succ();
2574     if (!succ->is_post_visited()) {
2575       // Found backedge since predecessor post visited, but successor is not
2576       assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2577 
2578       // Create a LoopNode to mark this loop.
2579       lp = new (arena()) Loop(succ, blk);
2580       if (succ->loop() == NULL)
2581         succ->set_loop(lp);
2582       // succ->loop will be updated to innermost loop on a later call, when blk==succ
2583 
2584     } else {  // Nested loop
2585       lp = succ->loop();
2586 
2587       // If succ is loop head, find outer loop.
2588       while (lp != NULL && lp->head() == succ) {
2589         lp = lp->parent();
2590       }
2591       if (lp == NULL) {
2592         // Infinite loop, it's parent is the root
2593         lp = loop_tree_root();
2594       }
2595     }
2596 
2597     // Check for irreducible loop.
2598     // Successor has already been visited. If the successor's loop head
2599     // has already been post-visited, then this is another entry into the loop.
2600     while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2601       _has_irreducible_entry = true;
2602       lp->set_irreducible(succ);
2603       if (!succ->is_on_work_list()) {
2604         // Assume irreducible entries need more data flow
2605         add_to_work_list(succ);
2606       }
2607       Loop* plp = lp->parent();
2608       if (plp == NULL) {
2609         // This only happens for some irreducible cases.  The parent
2610         // will be updated during a later pass.
2611         break;
2612       }
2613       lp = plp;
2614     }
2615 
2616     // Merge loop tree branch for all successors.
2617     innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2618 
2619   } // end loop
2620 
2621   if (innermost == NULL) {
2622     assert(blk->successors()->length() == 0, "CFG exit");
2623     blk->set_loop(loop_tree_root());
2624   } else if (innermost->head() == blk) {
2625     // If loop header, complete the tree pointers
2626     if (blk->loop() != innermost) {
2627 #ifdef ASSERT
2628       assert(blk->loop()->head() == innermost->head(), "same head");
2629       Loop* dl;
2630       for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2631       assert(dl == blk->loop(), "blk->loop() already in innermost list");
2632 #endif
2633       blk->set_loop(innermost);
2634     }
2635     innermost->def_locals()->add(blk->def_locals());
2636     Loop* l = innermost;
2637     Loop* p = l->parent();
2638     while (p && l->head() == blk) {
2639       l->set_sibling(p->child());  // Put self on parents 'next child'
2640       p->set_child(l);             // Make self the first child of parent
2641       p->def_locals()->add(l->def_locals());
2642       l = p;                       // Walk up the parent chain
2643       p = l->parent();
2644     }
2645   } else {
2646     blk->set_loop(innermost);
2647     innermost->def_locals()->add(blk->def_locals());
2648   }
2649 }
2650 
2651 // ------------------------------------------------------------------
2652 // ciTypeFlow::Loop::contains
2653 //
2654 // Returns true if lp is nested loop.
2655 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2656   assert(lp != NULL, "");
2657   if (this == lp || head() == lp->head()) return true;
2658   int depth1 = depth();
2659   int depth2 = lp->depth();
2660   if (depth1 > depth2)
2661     return false;
2662   while (depth1 < depth2) {
2663     depth2--;
2664     lp = lp->parent();
2665   }
2666   return this == lp;
2667 }
2668 
2669 // ------------------------------------------------------------------
2670 // ciTypeFlow::Loop::depth
2671 //
2672 // Loop depth
2673 int ciTypeFlow::Loop::depth() const {
2674   int dp = 0;
2675   for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2676     dp++;
2677   return dp;
2678 }
2679 
2680 #ifndef PRODUCT
2681 // ------------------------------------------------------------------
2682 // ciTypeFlow::Loop::print
2683 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2684   for (int i = 0; i < indent; i++) st->print(" ");
2685   st->print("%d<-%d %s",
2686             is_root() ? 0 : this->head()->pre_order(),
2687             is_root() ? 0 : this->tail()->pre_order(),
2688             is_irreducible()?" irr":"");
2689   st->print(" defs: ");
2690   def_locals()->print_on(st, _head->outer()->method()->max_locals());
2691   st->cr();
2692   for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2693     ch->print(st, indent+2);
2694 }
2695 #endif
2696 
2697 // ------------------------------------------------------------------
2698 // ciTypeFlow::df_flow_types
2699 //
2700 // Perform the depth first type flow analysis. Helper for flow_types.
2701 void ciTypeFlow::df_flow_types(Block* start,
2702                                bool do_flow,
2703                                StateVector* temp_vector,
2704                                JsrSet* temp_set) {
2705   int dft_len = 100;
2706   GrowableArray<Block*> stk(dft_len);
2707 
2708   ciBlock* dummy = _methodBlocks->make_dummy_block();
2709   JsrSet* root_set = new JsrSet(NULL, 0);
2710   Block* root_head = new (arena()) Block(this, dummy, root_set);
2711   Block* root_tail = new (arena()) Block(this, dummy, root_set);
2712   root_head->set_pre_order(0);
2713   root_head->set_post_order(0);
2714   root_tail->set_pre_order(max_jint);
2715   root_tail->set_post_order(max_jint);
2716   set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2717 
2718   stk.push(start);
2719 
2720   _next_pre_order = 0;  // initialize pre_order counter
2721   _rpo_list = NULL;
2722   int next_po = 0;      // initialize post_order counter
2723 
2724   // Compute RPO and the control flow graph
2725   int size;
2726   while ((size = stk.length()) > 0) {
2727     Block* blk = stk.top(); // Leave node on stack
2728     if (!blk->is_visited()) {
2729       // forward arc in graph
2730       assert (!blk->has_pre_order(), "");
2731       blk->set_next_pre_order();
2732 
2733       if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2734         // Too many basic blocks.  Bail out.
2735         // This can happen when try/finally constructs are nested to depth N,
2736         // and there is O(2**N) cloning of jsr bodies.  See bug 4697245!
2737         // "MaxNodeLimit / 2" is used because probably the parser will
2738         // generate at least twice that many nodes and bail out.
2739         record_failure("too many basic blocks");
2740         return;
2741       }
2742       if (do_flow) {
2743         flow_block(blk, temp_vector, temp_set);
2744         if (failing()) return; // Watch for bailouts.
2745       }
2746     } else if (!blk->is_post_visited()) {
2747       // cross or back arc
2748       for (SuccIter iter(blk); !iter.done(); iter.next()) {
2749         Block* succ = iter.succ();
2750         if (!succ->is_visited()) {
2751           stk.push(succ);
2752         }
2753       }
2754       if (stk.length() == size) {
2755         // There were no additional children, post visit node now
2756         stk.pop(); // Remove node from stack
2757 
2758         build_loop_tree(blk);
2759         blk->set_post_order(next_po++);   // Assign post order
2760         prepend_to_rpo_list(blk);
2761         assert(blk->is_post_visited(), "");
2762 
2763         if (blk->is_loop_head() && !blk->is_on_work_list()) {
2764           // Assume loop heads need more data flow
2765           add_to_work_list(blk);
2766         }
2767       }
2768     } else {
2769       stk.pop(); // Remove post-visited node from stack
2770     }
2771   }
2772 }
2773 
2774 // ------------------------------------------------------------------
2775 // ciTypeFlow::flow_types
2776 //
2777 // Perform the type flow analysis, creating and cloning Blocks as
2778 // necessary.
2779 void ciTypeFlow::flow_types() {
2780   ResourceMark rm;
2781   StateVector* temp_vector = new StateVector(this);
2782   JsrSet* temp_set = new JsrSet(NULL, 16);
2783 
2784   // Create the method entry block.
2785   Block* start = block_at(start_bci(), temp_set);
2786 
2787   // Load the initial state into it.
2788   const StateVector* start_state = get_start_state();
2789   if (failing())  return;
2790   start->meet(start_state);
2791 
2792   // Depth first visit
2793   df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2794 
2795   if (failing())  return;
2796   assert(_rpo_list == start, "must be start");
2797 
2798   // Any loops found?
2799   if (loop_tree_root()->child() != NULL &&
2800       env()->comp_level() >= CompLevel_full_optimization) {
2801       // Loop optimizations are not performed on Tier1 compiles.
2802 
2803     bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2804 
2805     // If some loop heads were cloned, recompute postorder and loop tree
2806     if (changed) {
2807       loop_tree_root()->set_child(NULL);
2808       for (Block* blk = _rpo_list; blk != NULL;) {
2809         Block* next = blk->rpo_next();
2810         blk->df_init();
2811         blk = next;
2812       }
2813       df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2814     }
2815   }
2816 
2817   if (CITraceTypeFlow) {
2818     tty->print_cr("\nLoop tree");
2819     loop_tree_root()->print();
2820   }
2821 
2822   // Continue flow analysis until fixed point reached
2823 
2824   debug_only(int max_block = _next_pre_order;)
2825 
2826   while (!work_list_empty()) {
2827     Block* blk = work_list_next();
2828     assert (blk->has_post_order(), "post order assigned above");
2829 
2830     flow_block(blk, temp_vector, temp_set);
2831 
2832     assert (max_block == _next_pre_order, "no new blocks");
2833     assert (!failing(), "no more bailouts");
2834   }
2835 }
2836 
2837 // ------------------------------------------------------------------
2838 // ciTypeFlow::map_blocks
2839 //
2840 // Create the block map, which indexes blocks in reverse post-order.
2841 void ciTypeFlow::map_blocks() {
2842   assert(_block_map == NULL, "single initialization");
2843   int block_ct = _next_pre_order;
2844   _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2845   assert(block_ct == block_count(), "");
2846 
2847   Block* blk = _rpo_list;
2848   for (int m = 0; m < block_ct; m++) {
2849     int rpo = blk->rpo();
2850     assert(rpo == m, "should be sequential");
2851     _block_map[rpo] = blk;
2852     blk = blk->rpo_next();
2853   }
2854   assert(blk == NULL, "should be done");
2855 
2856   for (int j = 0; j < block_ct; j++) {
2857     assert(_block_map[j] != NULL, "must not drop any blocks");
2858     Block* block = _block_map[j];
2859     // Remove dead blocks from successor lists:
2860     for (int e = 0; e <= 1; e++) {
2861       GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2862       for (int k = 0; k < l->length(); k++) {
2863         Block* s = l->at(k);
2864         if (!s->has_post_order()) {
2865           if (CITraceTypeFlow) {
2866             tty->print("Removing dead %s successor of #%d: ", (e? "exceptional":  "normal"), block->pre_order());
2867             s->print_value_on(tty);
2868             tty->cr();
2869           }
2870           l->remove(s);
2871           --k;
2872         }
2873       }
2874     }
2875   }
2876 }
2877 
2878 // ------------------------------------------------------------------
2879 // ciTypeFlow::get_block_for
2880 //
2881 // Find a block with this ciBlock which has a compatible JsrSet.
2882 // If no such block exists, create it, unless the option is no_create.
2883 // If the option is create_backedge_copy, always create a fresh backedge copy.
2884 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2885   Arena* a = arena();
2886   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2887   if (blocks == NULL) {
2888     // Query only?
2889     if (option == no_create)  return NULL;
2890 
2891     // Allocate the growable array.
2892     blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2893     _idx_to_blocklist[ciBlockIndex] = blocks;
2894   }
2895 
2896   if (option != create_backedge_copy) {
2897     int len = blocks->length();
2898     for (int i = 0; i < len; i++) {
2899       Block* block = blocks->at(i);
2900       if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2901         return block;
2902       }
2903     }
2904   }
2905 
2906   // Query only?
2907   if (option == no_create)  return NULL;
2908 
2909   // We did not find a compatible block.  Create one.
2910   Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2911   if (option == create_backedge_copy)  new_block->set_backedge_copy(true);
2912   blocks->append(new_block);
2913   return new_block;
2914 }
2915 
2916 // ------------------------------------------------------------------
2917 // ciTypeFlow::backedge_copy_count
2918 //
2919 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2920   GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2921 
2922   if (blocks == NULL) {
2923     return 0;
2924   }
2925 
2926   int count = 0;
2927   int len = blocks->length();
2928   for (int i = 0; i < len; i++) {
2929     Block* block = blocks->at(i);
2930     if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2931       count++;
2932     }
2933   }
2934 
2935   return count;
2936 }
2937 
2938 // ------------------------------------------------------------------
2939 // ciTypeFlow::do_flow
2940 //
2941 // Perform type inference flow analysis.
2942 void ciTypeFlow::do_flow() {
2943   if (CITraceTypeFlow) {
2944     tty->print_cr("\nPerforming flow analysis on method");
2945     method()->print();
2946     if (is_osr_flow())  tty->print(" at OSR bci %d", start_bci());
2947     tty->cr();
2948     method()->print_codes();
2949   }
2950   if (CITraceTypeFlow) {
2951     tty->print_cr("Initial CI Blocks");
2952     print_on(tty);
2953   }
2954   flow_types();
2955   // Watch for bailouts.
2956   if (failing()) {
2957     return;
2958   }
2959 
2960   map_blocks();
2961 
2962   if (CIPrintTypeFlow || CITraceTypeFlow) {
2963     rpo_print_on(tty);
2964   }
2965 }
2966 
2967 // ------------------------------------------------------------------
2968 // ciTypeFlow::is_dominated_by
2969 //
2970 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
2971 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
2972   assert(!method()->has_jsrs(), "jsrs are not supported");
2973 
2974   ResourceMark rm;
2975   JsrSet* jsrs = new ciTypeFlow::JsrSet(NULL);
2976   int        index = _methodBlocks->block_containing(bci)->index();
2977   int    dom_index = _methodBlocks->block_containing(dom_bci)->index();
2978   Block*     block = get_block_for(index, jsrs, ciTypeFlow::no_create);
2979   Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
2980 
2981   // Start block dominates all other blocks
2982   if (start_block()->rpo() == dom_block->rpo()) {
2983     return true;
2984   }
2985 
2986   // Dominated[i] is true if block i is dominated by dom_block
2987   int num_blocks = block_count();
2988   bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
2989   for (int i = 0; i < num_blocks; ++i) {
2990     dominated[i] = true;
2991   }
2992   dominated[start_block()->rpo()] = false;
2993 
2994   // Iterative dominator algorithm
2995   bool changed = true;
2996   while (changed) {
2997     changed = false;
2998     // Use reverse postorder iteration
2999     for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3000       if (blk->is_start()) {
3001         // Ignore start block
3002         continue;
3003       }
3004       // The block is dominated if it is the dominating block
3005       // itself or if all predecessors are dominated.
3006       int index = blk->rpo();
3007       bool dom = (index == dom_block->rpo());
3008       if (!dom) {
3009         // Check if all predecessors are dominated
3010         dom = true;
3011         for (int i = 0; i < blk->predecessors()->length(); ++i) {
3012           Block* pred = blk->predecessors()->at(i);
3013           if (!dominated[pred->rpo()]) {
3014             dom = false;
3015             break;
3016           }
3017         }
3018       }
3019       // Update dominator information
3020       if (dominated[index] != dom) {
3021         changed = true;
3022         dominated[index] = dom;
3023       }
3024     }
3025   }
3026   // block dominated by dom_block?
3027   return dominated[block->rpo()];
3028 }
3029 
3030 // ------------------------------------------------------------------
3031 // ciTypeFlow::record_failure()
3032 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3033 // This is required because there is not a 1-1 relation between the ciEnv and
3034 // the TypeFlow passes within a compilation task.  For example, if the compiler
3035 // is considering inlining a method, it will request a TypeFlow.  If that fails,
3036 // the compilation as a whole may continue without the inlining.  Some TypeFlow
3037 // requests are not optional; if they fail the requestor is responsible for
3038 // copying the failure reason up to the ciEnv.  (See Parse::Parse.)
3039 void ciTypeFlow::record_failure(const char* reason) {
3040   if (env()->log() != NULL) {
3041     env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3042   }
3043   if (_failure_reason == NULL) {
3044     // Record the first failure reason.
3045     _failure_reason = reason;
3046   }
3047 }
3048 
3049 #ifndef PRODUCT
3050 // ------------------------------------------------------------------
3051 // ciTypeFlow::print_on
3052 void ciTypeFlow::print_on(outputStream* st) const {
3053   // Walk through CI blocks
3054   st->print_cr("********************************************************");
3055   st->print   ("TypeFlow for ");
3056   method()->name()->print_symbol_on(st);
3057   int limit_bci = code_size();
3058   st->print_cr("  %d bytes", limit_bci);
3059   ciMethodBlocks  *mblks = _methodBlocks;
3060   ciBlock* current = NULL;
3061   for (int bci = 0; bci < limit_bci; bci++) {
3062     ciBlock* blk = mblks->block_containing(bci);
3063     if (blk != NULL && blk != current) {
3064       current = blk;
3065       current->print_on(st);
3066 
3067       GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3068       int num_blocks = (blocks == NULL) ? 0 : blocks->length();
3069 
3070       if (num_blocks == 0) {
3071         st->print_cr("  No Blocks");
3072       } else {
3073         for (int i = 0; i < num_blocks; i++) {
3074           Block* block = blocks->at(i);
3075           block->print_on(st);
3076         }
3077       }
3078       st->print_cr("--------------------------------------------------------");
3079       st->cr();
3080     }
3081   }
3082   st->print_cr("********************************************************");
3083   st->cr();
3084 }
3085 
3086 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3087   st->print_cr("********************************************************");
3088   st->print   ("TypeFlow for ");
3089   method()->name()->print_symbol_on(st);
3090   int limit_bci = code_size();
3091   st->print_cr("  %d bytes", limit_bci);
3092   for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3093     blk->print_on(st);
3094     st->print_cr("--------------------------------------------------------");
3095     st->cr();
3096   }
3097   st->print_cr("********************************************************");
3098   st->cr();
3099 }
3100 #endif
--- EOF ---