ciTypeFlow.cpp revision 3602:da91efe96a93 
1/*
2 * Copyright (c) 2000, 2012, 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
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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 "runtime/deoptimization.hpp"
39#include "utilities/growableArray.hpp"
40
41// ciTypeFlow::JsrSet
42//
43// A JsrSet represents some set of JsrRecords.  This class
44// is used to record a set of all jsr routines which we permit
45// execution to return (ret) from.
46//
47// During abstract interpretation, JsrSets are used to determine
48// whether two paths which reach a given block are unique, and
49// should be cloned apart, or are compatible, and should merge
50// together.
51
52// ------------------------------------------------------------------
53// ciTypeFlow::JsrSet::JsrSet
54ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) {
55  if (arena != NULL) {
56    // Allocate growable array in Arena.
57    _set = new (arena) GrowableArray<JsrRecord*>(arena, default_len, 0, NULL);
58  } else {
59    // Allocate growable array in current ResourceArea.
60    _set = new GrowableArray<JsrRecord*>(4, 0, NULL, false);
61  }
62}
63
64// ------------------------------------------------------------------
65// ciTypeFlow::JsrSet::copy_into
66void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
67  int len = size();
68  jsrs->_set->clear();
69  for (int i = 0; i < len; i++) {
70    jsrs->_set->append(_set->at(i));
71  }
72}
73
74// ------------------------------------------------------------------
75// ciTypeFlow::JsrSet::is_compatible_with
76//
77// !!!! MISGIVINGS ABOUT THIS... disregard
78//
79// Is this JsrSet compatible with some other JsrSet?
80//
81// In set-theoretic terms, a JsrSet can be viewed as a partial function
82// from entry addresses to return addresses.  Two JsrSets A and B are
83// compatible iff
84//
85//   For any x,
86//   A(x) defined and B(x) defined implies A(x) == B(x)
87//
88// Less formally, two JsrSets are compatible when they have identical
89// return addresses for any entry addresses they share in common.
90bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
91  // Walk through both sets in parallel.  If the same entry address
92  // appears in both sets, then the return address must match for
93  // the sets to be compatible.
94  int size1 = size();
95  int size2 = other->size();
96
97  // Special case.  If nothing is on the jsr stack, then there can
98  // be no ret.
99  if (size2 == 0) {
100    return true;
101  } else if (size1 != size2) {
102    return false;
103  } else {
104    for (int i = 0; i < size1; i++) {
105      JsrRecord* record1 = record_at(i);
106      JsrRecord* record2 = other->record_at(i);
107      if (record1->entry_address() != record2->entry_address() ||
108          record1->return_address() != record2->return_address()) {
109        return false;
110      }
111    }
112    return true;
113  }
114
115#if 0
116  int pos1 = 0;
117  int pos2 = 0;
118  int size1 = size();
119  int size2 = other->size();
120  while (pos1 < size1 && pos2 < size2) {
121    JsrRecord* record1 = record_at(pos1);
122    JsrRecord* record2 = other->record_at(pos2);
123    int entry1 = record1->entry_address();
124    int entry2 = record2->entry_address();
125    if (entry1 < entry2) {
126      pos1++;
127    } else if (entry1 > entry2) {
128      pos2++;
129    } else {
130      if (record1->return_address() == record2->return_address()) {
131        pos1++;
132        pos2++;
133      } else {
134        // These two JsrSets are incompatible.
135        return false;
136      }
137    }
138  }
139  // The two JsrSets agree.
140  return true;
141#endif
142}
143
144// ------------------------------------------------------------------
145// ciTypeFlow::JsrSet::insert_jsr_record
146//
147// Insert the given JsrRecord into the JsrSet, maintaining the order
148// of the set and replacing any element with the same entry address.
149void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
150  int len = size();
151  int entry = record->entry_address();
152  int pos = 0;
153  for ( ; pos < len; pos++) {
154    JsrRecord* current = record_at(pos);
155    if (entry == current->entry_address()) {
156      // Stomp over this entry.
157      _set->at_put(pos, record);
158      assert(size() == len, "must be same size");
159      return;
160    } else if (entry < current->entry_address()) {
161      break;
162    }
163  }
164
165  // Insert the record into the list.
166  JsrRecord* swap = record;
167  JsrRecord* temp = NULL;
168  for ( ; pos < len; pos++) {
169    temp = _set->at(pos);
170    _set->at_put(pos, swap);
171    swap = temp;
172  }
173  _set->append(swap);
174  assert(size() == len+1, "must be larger");
175}
176
177// ------------------------------------------------------------------
178// ciTypeFlow::JsrSet::remove_jsr_record
179//
180// Remove the JsrRecord with the given return address from the JsrSet.
181void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
182  int len = size();
183  for (int i = 0; i < len; i++) {
184    if (record_at(i)->return_address() == return_address) {
185      // We have found the proper entry.  Remove it from the
186      // JsrSet and exit.
187      for (int j = i+1; j < len ; j++) {
188        _set->at_put(j-1, _set->at(j));
189      }
190      _set->trunc_to(len-1);
191      assert(size() == len-1, "must be smaller");
192      return;
193    }
194  }
195  assert(false, "verify: returning from invalid subroutine");
196}
197
198// ------------------------------------------------------------------
199// ciTypeFlow::JsrSet::apply_control
200//
201// Apply the effect of a control-flow bytecode on the JsrSet.  The
202// only bytecodes that modify the JsrSet are jsr and ret.
203void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
204                                       ciBytecodeStream* str,
205                                       ciTypeFlow::StateVector* state) {
206  Bytecodes::Code code = str->cur_bc();
207  if (code == Bytecodes::_jsr) {
208    JsrRecord* record =
209      analyzer->make_jsr_record(str->get_dest(), str->next_bci());
210    insert_jsr_record(record);
211  } else if (code == Bytecodes::_jsr_w) {
212    JsrRecord* record =
213      analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
214    insert_jsr_record(record);
215  } else if (code == Bytecodes::_ret) {
216    Cell local = state->local(str->get_index());
217    ciType* return_address = state->type_at(local);
218    assert(return_address->is_return_address(), "verify: wrong type");
219    if (size() == 0) {
220      // Ret-state underflow:  Hit a ret w/o any previous jsrs.  Bail out.
221      // This can happen when a loop is inside a finally clause (4614060).
222      analyzer->record_failure("OSR in finally clause");
223      return;
224    }
225    remove_jsr_record(return_address->as_return_address()->bci());
226  }
227}
228
229#ifndef PRODUCT
230// ------------------------------------------------------------------
231// ciTypeFlow::JsrSet::print_on
232void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
233  st->print("{ ");
234  int num_elements = size();
235  if (num_elements > 0) {
236    int i = 0;
237    for( ; i < num_elements - 1; i++) {
238      _set->at(i)->print_on(st);
239      st->print(", ");
240    }
241    _set->at(i)->print_on(st);
242    st->print(" ");
243  }
244  st->print("}");
245}
246#endif
247
248// ciTypeFlow::StateVector
249//
250// A StateVector summarizes the type information at some point in
251// the program.
252
253// ------------------------------------------------------------------
254// ciTypeFlow::StateVector::type_meet
255//
256// Meet two types.
257//
258// The semi-lattice of types use by this analysis are modeled on those
259// of the verifier.  The lattice is as follows:
260//
261//        top_type() >= all non-extremal types >= bottom_type
262//                             and
263//   Every primitive type is comparable only with itself.  The meet of
264//   reference types is determined by their kind: instance class,
265//   interface, or array class.  The meet of two types of the same
266//   kind is their least common ancestor.  The meet of two types of
267//   different kinds is always java.lang.Object.
268ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
269  assert(t1 != t2, "checked in caller");
270  if (t1->equals(top_type())) {
271    return t2;
272  } else if (t2->equals(top_type())) {
273    return t1;
274  } else if (t1->is_primitive_type() || t2->is_primitive_type()) {
275    // Special case null_type.  null_type meet any reference type T
276    // is T.  null_type meet null_type is null_type.
277    if (t1->equals(null_type())) {
278      if (!t2->is_primitive_type() || t2->equals(null_type())) {
279        return t2;
280      }
281    } else if (t2->equals(null_type())) {
282      if (!t1->is_primitive_type()) {
283        return t1;
284      }
285    }
286
287    // At least one of the two types is a non-top primitive type.
288    // The other type is not equal to it.  Fall to bottom.
289    return bottom_type();
290  } else {
291    // Both types are non-top non-primitive types.  That is,
292    // both types are either instanceKlasses or arrayKlasses.
293    ciKlass* object_klass = analyzer->env()->Object_klass();
294    ciKlass* k1 = t1->as_klass();
295    ciKlass* k2 = t2->as_klass();
296    if (k1->equals(object_klass) || k2->equals(object_klass)) {
297      return object_klass;
298    } else if (!k1->is_loaded() || !k2->is_loaded()) {
299      // Unloaded classes fall to java.lang.Object at a merge.
300      return object_klass;
301    } else if (k1->is_interface() != k2->is_interface()) {
302      // When an interface meets a non-interface, we get Object;
303      // This is what the verifier does.
304      return object_klass;
305    } else if (k1->is_array_klass() || k2->is_array_klass()) {
306      // When an array meets a non-array, we get Object.
307      // When objArray meets typeArray, we also get Object.
308      // And when typeArray meets different typeArray, we again get Object.
309      // But when objArray meets objArray, we look carefully at element types.
310      if (k1->is_obj_array_klass() && k2->is_obj_array_klass()) {
311        // Meet the element types, then construct the corresponding array type.
312        ciKlass* elem1 = k1->as_obj_array_klass()->element_klass();
313        ciKlass* elem2 = k2->as_obj_array_klass()->element_klass();
314        ciKlass* elem  = type_meet_internal(elem1, elem2, analyzer)->as_klass();
315        // Do an easy shortcut if one type is a super of the other.
316        if (elem == elem1) {
317          assert(k1 == ciObjArrayKlass::make(elem), "shortcut is OK");
318          return k1;
319        } else if (elem == elem2) {
320          assert(k2 == ciObjArrayKlass::make(elem), "shortcut is OK");
321          return k2;
322        } else {
323          return ciObjArrayKlass::make(elem);
324        }
325      } else {
326        return object_klass;
327      }
328    } else {
329      // Must be two plain old instance klasses.
330      assert(k1->is_instance_klass(), "previous cases handle non-instances");
331      assert(k2->is_instance_klass(), "previous cases handle non-instances");
332      return k1->least_common_ancestor(k2);
333    }
334  }
335}
336
337
338// ------------------------------------------------------------------
339// ciTypeFlow::StateVector::StateVector
340//
341// Build a new state vector
342ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
343  _outer = analyzer;
344  _stack_size = -1;
345  _monitor_count = -1;
346  // Allocate the _types array
347  int max_cells = analyzer->max_cells();
348  _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
349  for (int i=0; i<max_cells; i++) {
350    _types[i] = top_type();
351  }
352  _trap_bci = -1;
353  _trap_index = 0;
354  _def_locals.clear();
355}
356
357
358// ------------------------------------------------------------------
359// ciTypeFlow::get_start_state
360//
361// Set this vector to the method entry state.
362const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
363  StateVector* state = new StateVector(this);
364  if (is_osr_flow()) {
365    ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
366    if (non_osr_flow->failing()) {
367      record_failure(non_osr_flow->failure_reason());
368      return NULL;
369    }
370    JsrSet* jsrs = new JsrSet(NULL, 16);
371    Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
372    if (non_osr_block == NULL) {
373      record_failure("cannot reach OSR point");
374      return NULL;
375    }
376    // load up the non-OSR state at this point
377    non_osr_block->copy_state_into(state);
378    int non_osr_start = non_osr_block->start();
379    if (non_osr_start != start_bci()) {
380      // must flow forward from it
381      if (CITraceTypeFlow) {
382        tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
383      }
384      Block* block = block_at(non_osr_start, jsrs);
385      assert(block->limit() == start_bci(), "must flow forward to start");
386      flow_block(block, state, jsrs);
387    }
388    return state;
389    // Note:  The code below would be an incorrect for an OSR flow,
390    // even if it were possible for an OSR entry point to be at bci zero.
391  }
392  // "Push" the method signature into the first few locals.
393  state->set_stack_size(-max_locals());
394  if (!method()->is_static()) {
395    state->push(method()->holder());
396    assert(state->tos() == state->local(0), "");
397  }
398  for (ciSignatureStream str(method()->signature());
399       !str.at_return_type();
400       str.next()) {
401    state->push_translate(str.type());
402  }
403  // Set the rest of the locals to bottom.
404  Cell cell = state->next_cell(state->tos());
405  state->set_stack_size(0);
406  int limit = state->limit_cell();
407  for (; cell < limit; cell = state->next_cell(cell)) {
408    state->set_type_at(cell, state->bottom_type());
409  }
410  // Lock an object, if necessary.
411  state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
412  return state;
413}
414
415// ------------------------------------------------------------------
416// ciTypeFlow::StateVector::copy_into
417//
418// Copy our value into some other StateVector
419void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
420const {
421  copy->set_stack_size(stack_size());
422  copy->set_monitor_count(monitor_count());
423  Cell limit = limit_cell();
424  for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
425    copy->set_type_at(c, type_at(c));
426  }
427}
428
429// ------------------------------------------------------------------
430// ciTypeFlow::StateVector::meet
431//
432// Meets this StateVector with another, destructively modifying this
433// one.  Returns true if any modification takes place.
434bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
435  if (monitor_count() == -1) {
436    set_monitor_count(incoming->monitor_count());
437  }
438  assert(monitor_count() == incoming->monitor_count(), "monitors must match");
439
440  if (stack_size() == -1) {
441    set_stack_size(incoming->stack_size());
442    Cell limit = limit_cell();
443    #ifdef ASSERT
444    { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
445        assert(type_at(c) == top_type(), "");
446    } }
447    #endif
448    // Make a simple copy of the incoming state.
449    for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
450      set_type_at(c, incoming->type_at(c));
451    }
452    return true;  // it is always different the first time
453  }
454#ifdef ASSERT
455  if (stack_size() != incoming->stack_size()) {
456    _outer->method()->print_codes();
457    tty->print_cr("!!!! Stack size conflict");
458    tty->print_cr("Current state:");
459    print_on(tty);
460    tty->print_cr("Incoming state:");
461    ((StateVector*)incoming)->print_on(tty);
462  }
463#endif
464  assert(stack_size() == incoming->stack_size(), "sanity");
465
466  bool different = false;
467  Cell limit = limit_cell();
468  for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
469    ciType* t1 = type_at(c);
470    ciType* t2 = incoming->type_at(c);
471    if (!t1->equals(t2)) {
472      ciType* new_type = type_meet(t1, t2);
473      if (!t1->equals(new_type)) {
474        set_type_at(c, new_type);
475        different = true;
476      }
477    }
478  }
479  return different;
480}
481
482// ------------------------------------------------------------------
483// ciTypeFlow::StateVector::meet_exception
484//
485// Meets this StateVector with another, destructively modifying this
486// one.  The incoming state is coming via an exception.  Returns true
487// if any modification takes place.
488bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
489                                     const ciTypeFlow::StateVector* incoming) {
490  if (monitor_count() == -1) {
491    set_monitor_count(incoming->monitor_count());
492  }
493  assert(monitor_count() == incoming->monitor_count(), "monitors must match");
494
495  if (stack_size() == -1) {
496    set_stack_size(1);
497  }
498
499  assert(stack_size() ==  1, "must have one-element stack");
500
501  bool different = false;
502
503  // Meet locals from incoming array.
504  Cell limit = local(_outer->max_locals()-1);
505  for (Cell c = start_cell(); c <= limit; c = next_cell(c)) {
506    ciType* t1 = type_at(c);
507    ciType* t2 = incoming->type_at(c);
508    if (!t1->equals(t2)) {
509      ciType* new_type = type_meet(t1, t2);
510      if (!t1->equals(new_type)) {
511        set_type_at(c, new_type);
512        different = true;
513      }
514    }
515  }
516
517  // Handle stack separately.  When an exception occurs, the
518  // only stack entry is the exception instance.
519  ciType* tos_type = type_at_tos();
520  if (!tos_type->equals(exc)) {
521    ciType* new_type = type_meet(tos_type, exc);
522    if (!tos_type->equals(new_type)) {
523      set_type_at_tos(new_type);
524      different = true;
525    }
526  }
527
528  return different;
529}
530
531// ------------------------------------------------------------------
532// ciTypeFlow::StateVector::push_translate
533void ciTypeFlow::StateVector::push_translate(ciType* type) {
534  BasicType basic_type = type->basic_type();
535  if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
536      basic_type == T_BYTE    || basic_type == T_SHORT) {
537    push_int();
538  } else {
539    push(type);
540    if (type->is_two_word()) {
541      push(half_type(type));
542    }
543  }
544}
545
546// ------------------------------------------------------------------
547// ciTypeFlow::StateVector::do_aaload
548void ciTypeFlow::StateVector::do_aaload(ciBytecodeStream* str) {
549  pop_int();
550  ciObjArrayKlass* array_klass = pop_objArray();
551  if (array_klass == NULL) {
552    // Did aaload on a null reference; push a null and ignore the exception.
553    // This instruction will never continue normally.  All we have to do
554    // is report a value that will meet correctly with any downstream
555    // reference types on paths that will truly be executed.  This null type
556    // meets with any reference type to yield that same reference type.
557    // (The compiler will generate an unconditional exception here.)
558    push(null_type());
559    return;
560  }
561  if (!array_klass->is_loaded()) {
562    // Only fails for some -Xcomp runs
563    trap(str, array_klass,
564         Deoptimization::make_trap_request
565         (Deoptimization::Reason_unloaded,
566          Deoptimization::Action_reinterpret));
567    return;
568  }
569  ciKlass* element_klass = array_klass->element_klass();
570  if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
571    Untested("unloaded array element class in ciTypeFlow");
572    trap(str, element_klass,
573         Deoptimization::make_trap_request
574         (Deoptimization::Reason_unloaded,
575          Deoptimization::Action_reinterpret));
576  } else {
577    push_object(element_klass);
578  }
579}
580
581
582// ------------------------------------------------------------------
583// ciTypeFlow::StateVector::do_checkcast
584void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
585  bool will_link;
586  ciKlass* klass = str->get_klass(will_link);
587  if (!will_link) {
588    // VM's interpreter will not load 'klass' if object is NULL.
589    // Type flow after this block may still be needed in two situations:
590    // 1) C2 uses do_null_assert() and continues compilation for later blocks
591    // 2) C2 does an OSR compile in a later block (see bug 4778368).
592    pop_object();
593    do_null_assert(klass);
594  } else {
595    pop_object();
596    push_object(klass);
597  }
598}
599
600// ------------------------------------------------------------------
601// ciTypeFlow::StateVector::do_getfield
602void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
603  // could add assert here for type of object.
604  pop_object();
605  do_getstatic(str);
606}
607
608// ------------------------------------------------------------------
609// ciTypeFlow::StateVector::do_getstatic
610void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
611  bool will_link;
612  ciField* field = str->get_field(will_link);
613  if (!will_link) {
614    trap(str, field->holder(), str->get_field_holder_index());
615  } else {
616    ciType* field_type = field->type();
617    if (!field_type->is_loaded()) {
618      // Normally, we need the field's type to be loaded if we are to
619      // do anything interesting with its value.
620      // We used to do this:  trap(str, str->get_field_signature_index());
621      //
622      // There is one good reason not to trap here.  Execution can
623      // get past this "getfield" or "getstatic" if the value of
624      // the field is null.  As long as the value is null, the class
625      // does not need to be loaded!  The compiler must assume that
626      // the value of the unloaded class reference is null; if the code
627      // ever sees a non-null value, loading has occurred.
628      //
629      // This actually happens often enough to be annoying.  If the
630      // compiler throws an uncommon trap at this bytecode, you can
631      // get an endless loop of recompilations, when all the code
632      // needs to do is load a series of null values.  Also, a trap
633      // here can make an OSR entry point unreachable, triggering the
634      // assert on non_osr_block in ciTypeFlow::get_start_state.
635      // (See bug 4379915.)
636      do_null_assert(field_type->as_klass());
637    } else {
638      push_translate(field_type);
639    }
640  }
641}
642
643// ------------------------------------------------------------------
644// ciTypeFlow::StateVector::do_invoke
645void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
646                                        bool has_receiver) {
647  bool will_link;
648  ciSignature* declared_signature = NULL;
649  ciMethod* callee = str->get_method(will_link, &declared_signature);
650  assert(declared_signature != NULL, "cannot be null");
651  if (!will_link) {
652    // We weren't able to find the method.
653    if (str->cur_bc() == Bytecodes::_invokedynamic) {
654      trap(str, NULL,
655           Deoptimization::make_trap_request
656           (Deoptimization::Reason_uninitialized,
657            Deoptimization::Action_reinterpret));
658    } else {
659      ciKlass* unloaded_holder = callee->holder();
660      trap(str, unloaded_holder, str->get_method_holder_index());
661    }
662  } else {
663    // We are using the declared signature here because it might be
664    // different from the callee signature (Cf. invokedynamic and
665    // invokehandle).
666    ciSignatureStream sigstr(declared_signature);
667    const int arg_size = declared_signature->size();
668    const int stack_base = stack_size() - arg_size;
669    int i = 0;
670    for( ; !sigstr.at_return_type(); sigstr.next()) {
671      ciType* type = sigstr.type();
672      ciType* stack_type = type_at(stack(stack_base + i++));
673      // Do I want to check this type?
674      // assert(stack_type->is_subtype_of(type), "bad type for field value");
675      if (type->is_two_word()) {
676        ciType* stack_type2 = type_at(stack(stack_base + i++));
677        assert(stack_type2->equals(half_type(type)), "must be 2nd half");
678      }
679    }
680    assert(arg_size == i, "must match");
681    for (int j = 0; j < arg_size; j++) {
682      pop();
683    }
684    if (has_receiver) {
685      // Check this?
686      pop_object();
687    }
688    assert(!sigstr.is_done(), "must have return type");
689    ciType* return_type = sigstr.type();
690    if (!return_type->is_void()) {
691      if (!return_type->is_loaded()) {
692        // As in do_getstatic(), generally speaking, we need the return type to
693        // be loaded if we are to do anything interesting with its value.
694        // We used to do this:  trap(str, str->get_method_signature_index());
695        //
696        // We do not trap here since execution can get past this invoke if
697        // the return value is null.  As long as the value is null, the class
698        // does not need to be loaded!  The compiler must assume that
699        // the value of the unloaded class reference is null; if the code
700        // ever sees a non-null value, loading has occurred.
701        //
702        // See do_getstatic() for similar explanation, as well as bug 4684993.
703        do_null_assert(return_type->as_klass());
704      } else {
705        push_translate(return_type);
706      }
707    }
708  }
709}
710
711// ------------------------------------------------------------------
712// ciTypeFlow::StateVector::do_jsr
713void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
714  push(ciReturnAddress::make(str->next_bci()));
715}
716
717// ------------------------------------------------------------------
718// ciTypeFlow::StateVector::do_ldc
719void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
720  ciConstant con = str->get_constant();
721  BasicType basic_type = con.basic_type();
722  if (basic_type == T_ILLEGAL) {
723    // OutOfMemoryError in the CI while loading constant
724    push_null();
725    outer()->record_failure("ldc did not link");
726    return;
727  }
728  if (basic_type == T_OBJECT || basic_type == T_ARRAY) {
729    ciObject* obj = con.as_object();
730    if (obj->is_null_object()) {
731      push_null();
732    } else {
733      assert(obj->is_instance(), "must be java_mirror of klass");
734      push_object(obj->klass());
735    }
736  } else {
737    push_translate(ciType::make(basic_type));
738  }
739}
740
741// ------------------------------------------------------------------
742// ciTypeFlow::StateVector::do_multianewarray
743void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
744  int dimensions = str->get_dimensions();
745  bool will_link;
746  ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
747  if (!will_link) {
748    trap(str, array_klass, str->get_klass_index());
749  } else {
750    for (int i = 0; i < dimensions; i++) {
751      pop_int();
752    }
753    push_object(array_klass);
754  }
755}
756
757// ------------------------------------------------------------------
758// ciTypeFlow::StateVector::do_new
759void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
760  bool will_link;
761  ciKlass* klass = str->get_klass(will_link);
762  if (!will_link || str->is_unresolved_klass()) {
763    trap(str, klass, str->get_klass_index());
764  } else {
765    push_object(klass);
766  }
767}
768
769// ------------------------------------------------------------------
770// ciTypeFlow::StateVector::do_newarray
771void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
772  pop_int();
773  ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
774  push_object(klass);
775}
776
777// ------------------------------------------------------------------
778// ciTypeFlow::StateVector::do_putfield
779void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
780  do_putstatic(str);
781  if (_trap_bci != -1)  return;  // unloaded field holder, etc.
782  // could add assert here for type of object.
783  pop_object();
784}
785
786// ------------------------------------------------------------------
787// ciTypeFlow::StateVector::do_putstatic
788void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
789  bool will_link;
790  ciField* field = str->get_field(will_link);
791  if (!will_link) {
792    trap(str, field->holder(), str->get_field_holder_index());
793  } else {
794    ciType* field_type = field->type();
795    ciType* type = pop_value();
796    // Do I want to check this type?
797    //      assert(type->is_subtype_of(field_type), "bad type for field value");
798    if (field_type->is_two_word()) {
799      ciType* type2 = pop_value();
800      assert(type2->is_two_word(), "must be 2nd half");
801      assert(type == half_type(type2), "must be 2nd half");
802    }
803  }
804}
805
806// ------------------------------------------------------------------
807// ciTypeFlow::StateVector::do_ret
808void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
809  Cell index = local(str->get_index());
810
811  ciType* address = type_at(index);
812  assert(address->is_return_address(), "bad return address");
813  set_type_at(index, bottom_type());
814}
815
816// ------------------------------------------------------------------
817// ciTypeFlow::StateVector::trap
818//
819// Stop interpretation of this path with a trap.
820void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
821  _trap_bci = str->cur_bci();
822  _trap_index = index;
823
824  // Log information about this trap:
825  CompileLog* log = outer()->env()->log();
826  if (log != NULL) {
827    int mid = log->identify(outer()->method());
828    int kid = (klass == NULL)? -1: log->identify(klass);
829    log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
830    char buf[100];
831    log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
832                                                          index));
833    if (kid >= 0)
834      log->print(" klass='%d'", kid);
835    log->end_elem();
836  }
837}
838
839// ------------------------------------------------------------------
840// ciTypeFlow::StateVector::do_null_assert
841// Corresponds to graphKit::do_null_assert.
842void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
843  if (unloaded_klass->is_loaded()) {
844    // We failed to link, but we can still compute with this class,
845    // since it is loaded somewhere.  The compiler will uncommon_trap
846    // if the object is not null, but the typeflow pass can not assume
847    // that the object will be null, otherwise it may incorrectly tell
848    // the parser that an object is known to be null. 4761344, 4807707
849    push_object(unloaded_klass);
850  } else {
851    // The class is not loaded anywhere.  It is safe to model the
852    // null in the typestates, because we can compile in a null check
853    // which will deoptimize us if someone manages to load the
854    // class later.
855    push_null();
856  }
857}
858
859
860// ------------------------------------------------------------------
861// ciTypeFlow::StateVector::apply_one_bytecode
862//
863// Apply the effect of one bytecode to this StateVector
864bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
865  _trap_bci = -1;
866  _trap_index = 0;
867
868  if (CITraceTypeFlow) {
869    tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
870                  Bytecodes::name(str->cur_bc()));
871  }
872
873  switch(str->cur_bc()) {
874  case Bytecodes::_aaload: do_aaload(str);                       break;
875
876  case Bytecodes::_aastore:
877    {
878      pop_object();
879      pop_int();
880      pop_objArray();
881      break;
882    }
883  case Bytecodes::_aconst_null:
884    {
885      push_null();
886      break;
887    }
888  case Bytecodes::_aload:   load_local_object(str->get_index());    break;
889  case Bytecodes::_aload_0: load_local_object(0);                   break;
890  case Bytecodes::_aload_1: load_local_object(1);                   break;
891  case Bytecodes::_aload_2: load_local_object(2);                   break;
892  case Bytecodes::_aload_3: load_local_object(3);                   break;
893
894  case Bytecodes::_anewarray:
895    {
896      pop_int();
897      bool will_link;
898      ciKlass* element_klass = str->get_klass(will_link);
899      if (!will_link) {
900        trap(str, element_klass, str->get_klass_index());
901      } else {
902        push_object(ciObjArrayKlass::make(element_klass));
903      }
904      break;
905    }
906  case Bytecodes::_areturn:
907  case Bytecodes::_ifnonnull:
908  case Bytecodes::_ifnull:
909    {
910      pop_object();
911      break;
912    }
913  case Bytecodes::_monitorenter:
914    {
915      pop_object();
916      set_monitor_count(monitor_count() + 1);
917      break;
918    }
919  case Bytecodes::_monitorexit:
920    {
921      pop_object();
922      assert(monitor_count() > 0, "must be a monitor to exit from");
923      set_monitor_count(monitor_count() - 1);
924      break;
925    }
926  case Bytecodes::_arraylength:
927    {
928      pop_array();
929      push_int();
930      break;
931    }
932  case Bytecodes::_astore:   store_local_object(str->get_index());  break;
933  case Bytecodes::_astore_0: store_local_object(0);                 break;
934  case Bytecodes::_astore_1: store_local_object(1);                 break;
935  case Bytecodes::_astore_2: store_local_object(2);                 break;
936  case Bytecodes::_astore_3: store_local_object(3);                 break;
937
938  case Bytecodes::_athrow:
939    {
940      NEEDS_CLEANUP;
941      pop_object();
942      break;
943    }
944  case Bytecodes::_baload:
945  case Bytecodes::_caload:
946  case Bytecodes::_iaload:
947  case Bytecodes::_saload:
948    {
949      pop_int();
950      ciTypeArrayKlass* array_klass = pop_typeArray();
951      // Put assert here for right type?
952      push_int();
953      break;
954    }
955  case Bytecodes::_bastore:
956  case Bytecodes::_castore:
957  case Bytecodes::_iastore:
958  case Bytecodes::_sastore:
959    {
960      pop_int();
961      pop_int();
962      pop_typeArray();
963      // assert here?
964      break;
965    }
966  case Bytecodes::_bipush:
967  case Bytecodes::_iconst_m1:
968  case Bytecodes::_iconst_0:
969  case Bytecodes::_iconst_1:
970  case Bytecodes::_iconst_2:
971  case Bytecodes::_iconst_3:
972  case Bytecodes::_iconst_4:
973  case Bytecodes::_iconst_5:
974  case Bytecodes::_sipush:
975    {
976      push_int();
977      break;
978    }
979  case Bytecodes::_checkcast: do_checkcast(str);                  break;
980
981  case Bytecodes::_d2f:
982    {
983      pop_double();
984      push_float();
985      break;
986    }
987  case Bytecodes::_d2i:
988    {
989      pop_double();
990      push_int();
991      break;
992    }
993  case Bytecodes::_d2l:
994    {
995      pop_double();
996      push_long();
997      break;
998    }
999  case Bytecodes::_dadd:
1000  case Bytecodes::_ddiv:
1001  case Bytecodes::_dmul:
1002  case Bytecodes::_drem:
1003  case Bytecodes::_dsub:
1004    {
1005      pop_double();
1006      pop_double();
1007      push_double();
1008      break;
1009    }
1010  case Bytecodes::_daload:
1011    {
1012      pop_int();
1013      ciTypeArrayKlass* array_klass = pop_typeArray();
1014      // Put assert here for right type?
1015      push_double();
1016      break;
1017    }
1018  case Bytecodes::_dastore:
1019    {
1020      pop_double();
1021      pop_int();
1022      pop_typeArray();
1023      // assert here?
1024      break;
1025    }
1026  case Bytecodes::_dcmpg:
1027  case Bytecodes::_dcmpl:
1028    {
1029      pop_double();
1030      pop_double();
1031      push_int();
1032      break;
1033    }
1034  case Bytecodes::_dconst_0:
1035  case Bytecodes::_dconst_1:
1036    {
1037      push_double();
1038      break;
1039    }
1040  case Bytecodes::_dload:   load_local_double(str->get_index());    break;
1041  case Bytecodes::_dload_0: load_local_double(0);                   break;
1042  case Bytecodes::_dload_1: load_local_double(1);                   break;
1043  case Bytecodes::_dload_2: load_local_double(2);                   break;
1044  case Bytecodes::_dload_3: load_local_double(3);                   break;
1045
1046  case Bytecodes::_dneg:
1047    {
1048      pop_double();
1049      push_double();
1050      break;
1051    }
1052  case Bytecodes::_dreturn:
1053    {
1054      pop_double();
1055      break;
1056    }
1057  case Bytecodes::_dstore:   store_local_double(str->get_index());  break;
1058  case Bytecodes::_dstore_0: store_local_double(0);                 break;
1059  case Bytecodes::_dstore_1: store_local_double(1);                 break;
1060  case Bytecodes::_dstore_2: store_local_double(2);                 break;
1061  case Bytecodes::_dstore_3: store_local_double(3);                 break;
1062
1063  case Bytecodes::_dup:
1064    {
1065      push(type_at_tos());
1066      break;
1067    }
1068  case Bytecodes::_dup_x1:
1069    {
1070      ciType* value1 = pop_value();
1071      ciType* value2 = pop_value();
1072      push(value1);
1073      push(value2);
1074      push(value1);
1075      break;
1076    }
1077  case Bytecodes::_dup_x2:
1078    {
1079      ciType* value1 = pop_value();
1080      ciType* value2 = pop_value();
1081      ciType* value3 = pop_value();
1082      push(value1);
1083      push(value3);
1084      push(value2);
1085      push(value1);
1086      break;
1087    }
1088  case Bytecodes::_dup2:
1089    {
1090      ciType* value1 = pop_value();
1091      ciType* value2 = pop_value();
1092      push(value2);
1093      push(value1);
1094      push(value2);
1095      push(value1);
1096      break;
1097    }
1098  case Bytecodes::_dup2_x1:
1099    {
1100      ciType* value1 = pop_value();
1101      ciType* value2 = pop_value();
1102      ciType* value3 = pop_value();
1103      push(value2);
1104      push(value1);
1105      push(value3);
1106      push(value2);
1107      push(value1);
1108      break;
1109    }
1110  case Bytecodes::_dup2_x2:
1111    {
1112      ciType* value1 = pop_value();
1113      ciType* value2 = pop_value();
1114      ciType* value3 = pop_value();
1115      ciType* value4 = pop_value();
1116      push(value2);
1117      push(value1);
1118      push(value4);
1119      push(value3);
1120      push(value2);
1121      push(value1);
1122      break;
1123    }
1124  case Bytecodes::_f2d:
1125    {
1126      pop_float();
1127      push_double();
1128      break;
1129    }
1130  case Bytecodes::_f2i:
1131    {
1132      pop_float();
1133      push_int();
1134      break;
1135    }
1136  case Bytecodes::_f2l:
1137    {
1138      pop_float();
1139      push_long();
1140      break;
1141    }
1142  case Bytecodes::_fadd:
1143  case Bytecodes::_fdiv:
1144  case Bytecodes::_fmul:
1145  case Bytecodes::_frem:
1146  case Bytecodes::_fsub:
1147    {
1148      pop_float();
1149      pop_float();
1150      push_float();
1151      break;
1152    }
1153  case Bytecodes::_faload:
1154    {
1155      pop_int();
1156      ciTypeArrayKlass* array_klass = pop_typeArray();
1157      // Put assert here.
1158      push_float();
1159      break;
1160    }
1161  case Bytecodes::_fastore:
1162    {
1163      pop_float();
1164      pop_int();
1165      ciTypeArrayKlass* array_klass = pop_typeArray();
1166      // Put assert here.
1167      break;
1168    }
1169  case Bytecodes::_fcmpg:
1170  case Bytecodes::_fcmpl:
1171    {
1172      pop_float();
1173      pop_float();
1174      push_int();
1175      break;
1176    }
1177  case Bytecodes::_fconst_0:
1178  case Bytecodes::_fconst_1:
1179  case Bytecodes::_fconst_2:
1180    {
1181      push_float();
1182      break;
1183    }
1184  case Bytecodes::_fload:   load_local_float(str->get_index());     break;
1185  case Bytecodes::_fload_0: load_local_float(0);                    break;
1186  case Bytecodes::_fload_1: load_local_float(1);                    break;
1187  case Bytecodes::_fload_2: load_local_float(2);                    break;
1188  case Bytecodes::_fload_3: load_local_float(3);                    break;
1189
1190  case Bytecodes::_fneg:
1191    {
1192      pop_float();
1193      push_float();
1194      break;
1195    }
1196  case Bytecodes::_freturn:
1197    {
1198      pop_float();
1199      break;
1200    }
1201  case Bytecodes::_fstore:    store_local_float(str->get_index());   break;
1202  case Bytecodes::_fstore_0:  store_local_float(0);                  break;
1203  case Bytecodes::_fstore_1:  store_local_float(1);                  break;
1204  case Bytecodes::_fstore_2:  store_local_float(2);                  break;
1205  case Bytecodes::_fstore_3:  store_local_float(3);                  break;
1206
1207  case Bytecodes::_getfield:  do_getfield(str);                      break;
1208  case Bytecodes::_getstatic: do_getstatic(str);                     break;
1209
1210  case Bytecodes::_goto:
1211  case Bytecodes::_goto_w:
1212  case Bytecodes::_nop:
1213  case Bytecodes::_return:
1214    {
1215      // do nothing.
1216      break;
1217    }
1218  case Bytecodes::_i2b:
1219  case Bytecodes::_i2c:
1220  case Bytecodes::_i2s:
1221  case Bytecodes::_ineg:
1222    {
1223      pop_int();
1224      push_int();
1225      break;
1226    }
1227  case Bytecodes::_i2d:
1228    {
1229      pop_int();
1230      push_double();
1231      break;
1232    }
1233  case Bytecodes::_i2f:
1234    {
1235      pop_int();
1236      push_float();
1237      break;
1238    }
1239  case Bytecodes::_i2l:
1240    {
1241      pop_int();
1242      push_long();
1243      break;
1244    }
1245  case Bytecodes::_iadd:
1246  case Bytecodes::_iand:
1247  case Bytecodes::_idiv:
1248  case Bytecodes::_imul:
1249  case Bytecodes::_ior:
1250  case Bytecodes::_irem:
1251  case Bytecodes::_ishl:
1252  case Bytecodes::_ishr:
1253  case Bytecodes::_isub:
1254  case Bytecodes::_iushr:
1255  case Bytecodes::_ixor:
1256    {
1257      pop_int();
1258      pop_int();
1259      push_int();
1260      break;
1261    }
1262  case Bytecodes::_if_acmpeq:
1263  case Bytecodes::_if_acmpne:
1264    {
1265      pop_object();
1266      pop_object();
1267      break;
1268    }
1269  case Bytecodes::_if_icmpeq:
1270  case Bytecodes::_if_icmpge:
1271  case Bytecodes::_if_icmpgt:
1272  case Bytecodes::_if_icmple:
1273  case Bytecodes::_if_icmplt:
1274  case Bytecodes::_if_icmpne:
1275    {
1276      pop_int();
1277      pop_int();
1278      break;
1279    }
1280  case Bytecodes::_ifeq:
1281  case Bytecodes::_ifle:
1282  case Bytecodes::_iflt:
1283  case Bytecodes::_ifge:
1284  case Bytecodes::_ifgt:
1285  case Bytecodes::_ifne:
1286  case Bytecodes::_ireturn:
1287  case Bytecodes::_lookupswitch:
1288  case Bytecodes::_tableswitch:
1289    {
1290      pop_int();
1291      break;
1292    }
1293  case Bytecodes::_iinc:
1294    {
1295      int lnum = str->get_index();
1296      check_int(local(lnum));
1297      store_to_local(lnum);
1298      break;
1299    }
1300  case Bytecodes::_iload:   load_local_int(str->get_index()); break;
1301  case Bytecodes::_iload_0: load_local_int(0);                      break;
1302  case Bytecodes::_iload_1: load_local_int(1);                      break;
1303  case Bytecodes::_iload_2: load_local_int(2);                      break;
1304  case Bytecodes::_iload_3: load_local_int(3);                      break;
1305
1306  case Bytecodes::_instanceof:
1307    {
1308      // Check for uncommon trap:
1309      do_checkcast(str);
1310      pop_object();
1311      push_int();
1312      break;
1313    }
1314  case Bytecodes::_invokeinterface: do_invoke(str, true);           break;
1315  case Bytecodes::_invokespecial:   do_invoke(str, true);           break;
1316  case Bytecodes::_invokestatic:    do_invoke(str, false);          break;
1317  case Bytecodes::_invokevirtual:   do_invoke(str, true);           break;
1318  case Bytecodes::_invokedynamic:   do_invoke(str, false);          break;
1319
1320  case Bytecodes::_istore:   store_local_int(str->get_index());     break;
1321  case Bytecodes::_istore_0: store_local_int(0);                    break;
1322  case Bytecodes::_istore_1: store_local_int(1);                    break;
1323  case Bytecodes::_istore_2: store_local_int(2);                    break;
1324  case Bytecodes::_istore_3: store_local_int(3);                    break;
1325
1326  case Bytecodes::_jsr:
1327  case Bytecodes::_jsr_w: do_jsr(str);                              break;
1328
1329  case Bytecodes::_l2d:
1330    {
1331      pop_long();
1332      push_double();
1333      break;
1334    }
1335  case Bytecodes::_l2f:
1336    {
1337      pop_long();
1338      push_float();
1339      break;
1340    }
1341  case Bytecodes::_l2i:
1342    {
1343      pop_long();
1344      push_int();
1345      break;
1346    }
1347  case Bytecodes::_ladd:
1348  case Bytecodes::_land:
1349  case Bytecodes::_ldiv:
1350  case Bytecodes::_lmul:
1351  case Bytecodes::_lor:
1352  case Bytecodes::_lrem:
1353  case Bytecodes::_lsub:
1354  case Bytecodes::_lxor:
1355    {
1356      pop_long();
1357      pop_long();
1358      push_long();
1359      break;
1360    }
1361  case Bytecodes::_laload:
1362    {
1363      pop_int();
1364      ciTypeArrayKlass* array_klass = pop_typeArray();
1365      // Put assert here for right type?
1366      push_long();
1367      break;
1368    }
1369  case Bytecodes::_lastore:
1370    {
1371      pop_long();
1372      pop_int();
1373      pop_typeArray();
1374      // assert here?
1375      break;
1376    }
1377  case Bytecodes::_lcmp:
1378    {
1379      pop_long();
1380      pop_long();
1381      push_int();
1382      break;
1383    }
1384  case Bytecodes::_lconst_0:
1385  case Bytecodes::_lconst_1:
1386    {
1387      push_long();
1388      break;
1389    }
1390  case Bytecodes::_ldc:
1391  case Bytecodes::_ldc_w:
1392  case Bytecodes::_ldc2_w:
1393    {
1394      do_ldc(str);
1395      break;
1396    }
1397
1398  case Bytecodes::_lload:   load_local_long(str->get_index());      break;
1399  case Bytecodes::_lload_0: load_local_long(0);                     break;
1400  case Bytecodes::_lload_1: load_local_long(1);                     break;
1401  case Bytecodes::_lload_2: load_local_long(2);                     break;
1402  case Bytecodes::_lload_3: load_local_long(3);                     break;
1403
1404  case Bytecodes::_lneg:
1405    {
1406      pop_long();
1407      push_long();
1408      break;
1409    }
1410  case Bytecodes::_lreturn:
1411    {
1412      pop_long();
1413      break;
1414    }
1415  case Bytecodes::_lshl:
1416  case Bytecodes::_lshr:
1417  case Bytecodes::_lushr:
1418    {
1419      pop_int();
1420      pop_long();
1421      push_long();
1422      break;
1423    }
1424  case Bytecodes::_lstore:   store_local_long(str->get_index());    break;
1425  case Bytecodes::_lstore_0: store_local_long(0);                   break;
1426  case Bytecodes::_lstore_1: store_local_long(1);                   break;
1427  case Bytecodes::_lstore_2: store_local_long(2);                   break;
1428  case Bytecodes::_lstore_3: store_local_long(3);                   break;
1429
1430  case Bytecodes::_multianewarray: do_multianewarray(str);          break;
1431
1432  case Bytecodes::_new:      do_new(str);                           break;
1433
1434  case Bytecodes::_newarray: do_newarray(str);                      break;
1435
1436  case Bytecodes::_pop:
1437    {
1438      pop();
1439      break;
1440    }
1441  case Bytecodes::_pop2:
1442    {
1443      pop();
1444      pop();
1445      break;
1446    }
1447
1448  case Bytecodes::_putfield:       do_putfield(str);                 break;
1449  case Bytecodes::_putstatic:      do_putstatic(str);                break;
1450
1451  case Bytecodes::_ret: do_ret(str);                                 break;
1452
1453  case Bytecodes::_swap:
1454    {
1455      ciType* value1 = pop_value();
1456      ciType* value2 = pop_value();
1457      push(value1);
1458      push(value2);
1459      break;
1460    }
1461  case Bytecodes::_wide:
1462  default:
1463    {
1464      // The iterator should skip this.
1465      ShouldNotReachHere();
1466      break;
1467    }
1468  }
1469
1470  if (CITraceTypeFlow) {
1471    print_on(tty);
1472  }
1473
1474  return (_trap_bci != -1);
1475}
1476
1477#ifndef PRODUCT
1478// ------------------------------------------------------------------
1479// ciTypeFlow::StateVector::print_cell_on
1480void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1481  ciType* type = type_at(c);
1482  if (type == top_type()) {
1483    st->print("top");
1484  } else if (type == bottom_type()) {
1485    st->print("bottom");
1486  } else if (type == null_type()) {
1487    st->print("null");
1488  } else if (type == long2_type()) {
1489    st->print("long2");
1490  } else if (type == double2_type()) {
1491    st->print("double2");
1492  } else if (is_int(type)) {
1493    st->print("int");
1494  } else if (is_long(type)) {
1495    st->print("long");
1496  } else if (is_float(type)) {
1497    st->print("float");
1498  } else if (is_double(type)) {
1499    st->print("double");
1500  } else if (type->is_return_address()) {
1501    st->print("address(%d)", type->as_return_address()->bci());
1502  } else {
1503    if (type->is_klass()) {
1504      type->as_klass()->name()->print_symbol_on(st);
1505    } else {
1506      st->print("UNEXPECTED TYPE");
1507      type->print();
1508    }
1509  }
1510}
1511
1512// ------------------------------------------------------------------
1513// ciTypeFlow::StateVector::print_on
1514void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1515  int num_locals   = _outer->max_locals();
1516  int num_stack    = stack_size();
1517  int num_monitors = monitor_count();
1518  st->print_cr("  State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1519  if (num_stack >= 0) {
1520    int i;
1521    for (i = 0; i < num_locals; i++) {
1522      st->print("    local %2d : ", i);
1523      print_cell_on(st, local(i));
1524      st->cr();
1525    }
1526    for (i = 0; i < num_stack; i++) {
1527      st->print("    stack %2d : ", i);
1528      print_cell_on(st, stack(i));
1529      st->cr();
1530    }
1531  }
1532}
1533#endif
1534
1535
1536// ------------------------------------------------------------------
1537// ciTypeFlow::SuccIter::next
1538//
1539void ciTypeFlow::SuccIter::next() {
1540  int succ_ct = _pred->successors()->length();
1541  int next = _index + 1;
1542  if (next < succ_ct) {
1543    _index = next;
1544    _succ = _pred->successors()->at(next);
1545    return;
1546  }
1547  for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1548    // Do not compile any code for unloaded exception types.
1549    // Following compiler passes are responsible for doing this also.
1550    ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1551    if (exception_klass->is_loaded()) {
1552      _index = next;
1553      _succ = _pred->exceptions()->at(i);
1554      return;
1555    }
1556    next++;
1557  }
1558  _index = -1;
1559  _succ = NULL;
1560}
1561
1562// ------------------------------------------------------------------
1563// ciTypeFlow::SuccIter::set_succ
1564//
1565void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1566  int succ_ct = _pred->successors()->length();
1567  if (_index < succ_ct) {
1568    _pred->successors()->at_put(_index, succ);
1569  } else {
1570    int idx = _index - succ_ct;
1571    _pred->exceptions()->at_put(idx, succ);
1572  }
1573}
1574
1575// ciTypeFlow::Block
1576//
1577// A basic block.
1578
1579// ------------------------------------------------------------------
1580// ciTypeFlow::Block::Block
1581ciTypeFlow::Block::Block(ciTypeFlow* outer,
1582                         ciBlock *ciblk,
1583                         ciTypeFlow::JsrSet* jsrs) {
1584  _ciblock = ciblk;
1585  _exceptions = NULL;
1586  _exc_klasses = NULL;
1587  _successors = NULL;
1588  _state = new (outer->arena()) StateVector(outer);
1589  JsrSet* new_jsrs =
1590    new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1591  jsrs->copy_into(new_jsrs);
1592  _jsrs = new_jsrs;
1593  _next = NULL;
1594  _on_work_list = false;
1595  _backedge_copy = false;
1596  _has_monitorenter = false;
1597  _trap_bci = -1;
1598  _trap_index = 0;
1599  df_init();
1600
1601  if (CITraceTypeFlow) {
1602    tty->print_cr(">> Created new block");
1603    print_on(tty);
1604  }
1605
1606  assert(this->outer() == outer, "outer link set up");
1607  assert(!outer->have_block_count(), "must not have mapped blocks yet");
1608}
1609
1610// ------------------------------------------------------------------
1611// ciTypeFlow::Block::df_init
1612void ciTypeFlow::Block::df_init() {
1613  _pre_order = -1; assert(!has_pre_order(), "");
1614  _post_order = -1; assert(!has_post_order(), "");
1615  _loop = NULL;
1616  _irreducible_entry = false;
1617  _rpo_next = NULL;
1618}
1619
1620// ------------------------------------------------------------------
1621// ciTypeFlow::Block::successors
1622//
1623// Get the successors for this Block.
1624GrowableArray<ciTypeFlow::Block*>*
1625ciTypeFlow::Block::successors(ciBytecodeStream* str,
1626                              ciTypeFlow::StateVector* state,
1627                              ciTypeFlow::JsrSet* jsrs) {
1628  if (_successors == NULL) {
1629    if (CITraceTypeFlow) {
1630      tty->print(">> Computing successors for block ");
1631      print_value_on(tty);
1632      tty->cr();
1633    }
1634
1635    ciTypeFlow* analyzer = outer();
1636    Arena* arena = analyzer->arena();
1637    Block* block = NULL;
1638    bool has_successor = !has_trap() &&
1639                         (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1640    if (!has_successor) {
1641      _successors =
1642        new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1643      // No successors
1644    } else if (control() == ciBlock::fall_through_bci) {
1645      assert(str->cur_bci() == limit(), "bad block end");
1646      // This block simply falls through to the next.
1647      _successors =
1648        new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1649
1650      Block* block = analyzer->block_at(limit(), _jsrs);
1651      assert(_successors->length() == FALL_THROUGH, "");
1652      _successors->append(block);
1653    } else {
1654      int current_bci = str->cur_bci();
1655      int next_bci = str->next_bci();
1656      int branch_bci = -1;
1657      Block* target = NULL;
1658      assert(str->next_bci() == limit(), "bad block end");
1659      // This block is not a simple fall-though.  Interpret
1660      // the current bytecode to find our successors.
1661      switch (str->cur_bc()) {
1662      case Bytecodes::_ifeq:         case Bytecodes::_ifne:
1663      case Bytecodes::_iflt:         case Bytecodes::_ifge:
1664      case Bytecodes::_ifgt:         case Bytecodes::_ifle:
1665      case Bytecodes::_if_icmpeq:    case Bytecodes::_if_icmpne:
1666      case Bytecodes::_if_icmplt:    case Bytecodes::_if_icmpge:
1667      case Bytecodes::_if_icmpgt:    case Bytecodes::_if_icmple:
1668      case Bytecodes::_if_acmpeq:    case Bytecodes::_if_acmpne:
1669      case Bytecodes::_ifnull:       case Bytecodes::_ifnonnull:
1670        // Our successors are the branch target and the next bci.
1671        branch_bci = str->get_dest();
1672        _successors =
1673          new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1674        assert(_successors->length() == IF_NOT_TAKEN, "");
1675        _successors->append(analyzer->block_at(next_bci, jsrs));
1676        assert(_successors->length() == IF_TAKEN, "");
1677        _successors->append(analyzer->block_at(branch_bci, jsrs));
1678        break;
1679
1680      case Bytecodes::_goto:
1681        branch_bci = str->get_dest();
1682        _successors =
1683          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1684        assert(_successors->length() == GOTO_TARGET, "");
1685        _successors->append(analyzer->block_at(branch_bci, jsrs));
1686        break;
1687
1688      case Bytecodes::_jsr:
1689        branch_bci = str->get_dest();
1690        _successors =
1691          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1692        assert(_successors->length() == GOTO_TARGET, "");
1693        _successors->append(analyzer->block_at(branch_bci, jsrs));
1694        break;
1695
1696      case Bytecodes::_goto_w:
1697      case Bytecodes::_jsr_w:
1698        _successors =
1699          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1700        assert(_successors->length() == GOTO_TARGET, "");
1701        _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1702        break;
1703
1704      case Bytecodes::_tableswitch:  {
1705        Bytecode_tableswitch tableswitch(str);
1706
1707        int len = tableswitch.length();
1708        _successors =
1709          new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1710        int bci = current_bci + tableswitch.default_offset();
1711        Block* block = analyzer->block_at(bci, jsrs);
1712        assert(_successors->length() == SWITCH_DEFAULT, "");
1713        _successors->append(block);
1714        while (--len >= 0) {
1715          int bci = current_bci + tableswitch.dest_offset_at(len);
1716          block = analyzer->block_at(bci, jsrs);
1717          assert(_successors->length() >= SWITCH_CASES, "");
1718          _successors->append_if_missing(block);
1719        }
1720        break;
1721      }
1722
1723      case Bytecodes::_lookupswitch: {
1724        Bytecode_lookupswitch lookupswitch(str);
1725
1726        int npairs = lookupswitch.number_of_pairs();
1727        _successors =
1728          new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1729        int bci = current_bci + lookupswitch.default_offset();
1730        Block* block = analyzer->block_at(bci, jsrs);
1731        assert(_successors->length() == SWITCH_DEFAULT, "");
1732        _successors->append(block);
1733        while(--npairs >= 0) {
1734          LookupswitchPair pair = lookupswitch.pair_at(npairs);
1735          int bci = current_bci + pair.offset();
1736          Block* block = analyzer->block_at(bci, jsrs);
1737          assert(_successors->length() >= SWITCH_CASES, "");
1738          _successors->append_if_missing(block);
1739        }
1740        break;
1741      }
1742
1743      case Bytecodes::_athrow:     case Bytecodes::_ireturn:
1744      case Bytecodes::_lreturn:    case Bytecodes::_freturn:
1745      case Bytecodes::_dreturn:    case Bytecodes::_areturn:
1746      case Bytecodes::_return:
1747        _successors =
1748          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1749        // No successors
1750        break;
1751
1752      case Bytecodes::_ret: {
1753        _successors =
1754          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1755
1756        Cell local = state->local(str->get_index());
1757        ciType* return_address = state->type_at(local);
1758        assert(return_address->is_return_address(), "verify: wrong type");
1759        int bci = return_address->as_return_address()->bci();
1760        assert(_successors->length() == GOTO_TARGET, "");
1761        _successors->append(analyzer->block_at(bci, jsrs));
1762        break;
1763      }
1764
1765      case Bytecodes::_wide:
1766      default:
1767        ShouldNotReachHere();
1768        break;
1769      }
1770    }
1771  }
1772  return _successors;
1773}
1774
1775// ------------------------------------------------------------------
1776// ciTypeFlow::Block:compute_exceptions
1777//
1778// Compute the exceptional successors and types for this Block.
1779void ciTypeFlow::Block::compute_exceptions() {
1780  assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1781
1782  if (CITraceTypeFlow) {
1783    tty->print(">> Computing exceptions for block ");
1784    print_value_on(tty);
1785    tty->cr();
1786  }
1787
1788  ciTypeFlow* analyzer = outer();
1789  Arena* arena = analyzer->arena();
1790
1791  // Any bci in the block will do.
1792  ciExceptionHandlerStream str(analyzer->method(), start());
1793
1794  // Allocate our growable arrays.
1795  int exc_count = str.count();
1796  _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1797  _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1798                                                             0, NULL);
1799
1800  for ( ; !str.is_done(); str.next()) {
1801    ciExceptionHandler* handler = str.handler();
1802    int bci = handler->handler_bci();
1803    ciInstanceKlass* klass = NULL;
1804    if (bci == -1) {
1805      // There is no catch all.  It is possible to exit the method.
1806      break;
1807    }
1808    if (handler->is_catch_all()) {
1809      klass = analyzer->env()->Throwable_klass();
1810    } else {
1811      klass = handler->catch_klass();
1812    }
1813    _exceptions->append(analyzer->block_at(bci, _jsrs));
1814    _exc_klasses->append(klass);
1815  }
1816}
1817
1818// ------------------------------------------------------------------
1819// ciTypeFlow::Block::set_backedge_copy
1820// Use this only to make a pre-existing public block into a backedge copy.
1821void ciTypeFlow::Block::set_backedge_copy(bool z) {
1822  assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1823  _backedge_copy = z;
1824}
1825
1826// ------------------------------------------------------------------
1827// ciTypeFlow::Block::is_clonable_exit
1828//
1829// At most 2 normal successors, one of which continues looping,
1830// and all exceptional successors must exit.
1831bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1832  int normal_cnt  = 0;
1833  int in_loop_cnt = 0;
1834  for (SuccIter iter(this); !iter.done(); iter.next()) {
1835    Block* succ = iter.succ();
1836    if (iter.is_normal_ctrl()) {
1837      if (++normal_cnt > 2) return false;
1838      if (lp->contains(succ->loop())) {
1839        if (++in_loop_cnt > 1) return false;
1840      }
1841    } else {
1842      if (lp->contains(succ->loop())) return false;
1843    }
1844  }
1845  return in_loop_cnt == 1;
1846}
1847
1848// ------------------------------------------------------------------
1849// ciTypeFlow::Block::looping_succ
1850//
1851ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1852  assert(successors()->length() <= 2, "at most 2 normal successors");
1853  for (SuccIter iter(this); !iter.done(); iter.next()) {
1854    Block* succ = iter.succ();
1855    if (lp->contains(succ->loop())) {
1856      return succ;
1857    }
1858  }
1859  return NULL;
1860}
1861
1862#ifndef PRODUCT
1863// ------------------------------------------------------------------
1864// ciTypeFlow::Block::print_value_on
1865void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1866  if (has_pre_order()) st->print("#%-2d ", pre_order());
1867  if (has_rpo())       st->print("rpo#%-2d ", rpo());
1868  st->print("[%d - %d)", start(), limit());
1869  if (is_loop_head()) st->print(" lphd");
1870  if (is_irreducible_entry()) st->print(" irred");
1871  if (_jsrs->size() > 0) { st->print("/");  _jsrs->print_on(st); }
1872  if (is_backedge_copy())  st->print("/backedge_copy");
1873}
1874
1875// ------------------------------------------------------------------
1876// ciTypeFlow::Block::print_on
1877void ciTypeFlow::Block::print_on(outputStream* st) const {
1878  if ((Verbose || WizardMode) && (limit() >= 0)) {
1879    // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1880    outer()->method()->print_codes_on(start(), limit(), st);
1881  }
1882  st->print_cr("  ====================================================  ");
1883  st->print ("  ");
1884  print_value_on(st);
1885  st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1886  if (loop() && loop()->parent() != NULL) {
1887    st->print(" loops:");
1888    Loop* lp = loop();
1889    do {
1890      st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
1891      if (lp->is_irreducible()) st->print("(ir)");
1892      lp = lp->parent();
1893    } while (lp->parent() != NULL);
1894  }
1895  st->cr();
1896  _state->print_on(st);
1897  if (_successors == NULL) {
1898    st->print_cr("  No successor information");
1899  } else {
1900    int num_successors = _successors->length();
1901    st->print_cr("  Successors : %d", num_successors);
1902    for (int i = 0; i < num_successors; i++) {
1903      Block* successor = _successors->at(i);
1904      st->print("    ");
1905      successor->print_value_on(st);
1906      st->cr();
1907    }
1908  }
1909  if (_exceptions == NULL) {
1910    st->print_cr("  No exception information");
1911  } else {
1912    int num_exceptions = _exceptions->length();
1913    st->print_cr("  Exceptions : %d", num_exceptions);
1914    for (int i = 0; i < num_exceptions; i++) {
1915      Block* exc_succ = _exceptions->at(i);
1916      ciInstanceKlass* exc_klass = _exc_klasses->at(i);
1917      st->print("    ");
1918      exc_succ->print_value_on(st);
1919      st->print(" -- ");
1920      exc_klass->name()->print_symbol_on(st);
1921      st->cr();
1922    }
1923  }
1924  if (has_trap()) {
1925    st->print_cr("  Traps on %d with trap index %d", trap_bci(), trap_index());
1926  }
1927  st->print_cr("  ====================================================  ");
1928}
1929#endif
1930
1931#ifndef PRODUCT
1932// ------------------------------------------------------------------
1933// ciTypeFlow::LocalSet::print_on
1934void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
1935  st->print("{");
1936  for (int i = 0; i < max; i++) {
1937    if (test(i)) st->print(" %d", i);
1938  }
1939  if (limit > max) {
1940    st->print(" %d..%d ", max, limit);
1941  }
1942  st->print(" }");
1943}
1944#endif
1945
1946// ciTypeFlow
1947//
1948// This is a pass over the bytecodes which computes the following:
1949//   basic block structure
1950//   interpreter type-states (a la the verifier)
1951
1952// ------------------------------------------------------------------
1953// ciTypeFlow::ciTypeFlow
1954ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
1955  _env = env;
1956  _method = method;
1957  _methodBlocks = method->get_method_blocks();
1958  _max_locals = method->max_locals();
1959  _max_stack = method->max_stack();
1960  _code_size = method->code_size();
1961  _has_irreducible_entry = false;
1962  _osr_bci = osr_bci;
1963  _failure_reason = NULL;
1964  assert(0 <= start_bci() && start_bci() < code_size() , err_msg("correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size()));
1965  _work_list = NULL;
1966
1967  _ciblock_count = _methodBlocks->num_blocks();
1968  _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
1969  for (int i = 0; i < _ciblock_count; i++) {
1970    _idx_to_blocklist[i] = NULL;
1971  }
1972  _block_map = NULL;  // until all blocks are seen
1973  _jsr_count = 0;
1974  _jsr_records = NULL;
1975}
1976
1977// ------------------------------------------------------------------
1978// ciTypeFlow::work_list_next
1979//
1980// Get the next basic block from our work list.
1981ciTypeFlow::Block* ciTypeFlow::work_list_next() {
1982  assert(!work_list_empty(), "work list must not be empty");
1983  Block* next_block = _work_list;
1984  _work_list = next_block->next();
1985  next_block->set_next(NULL);
1986  next_block->set_on_work_list(false);
1987  return next_block;
1988}
1989
1990// ------------------------------------------------------------------
1991// ciTypeFlow::add_to_work_list
1992//
1993// Add a basic block to our work list.
1994// List is sorted by decreasing postorder sort (same as increasing RPO)
1995void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
1996  assert(!block->is_on_work_list(), "must not already be on work list");
1997
1998  if (CITraceTypeFlow) {
1999    tty->print(">> Adding block ");
2000    block->print_value_on(tty);
2001    tty->print_cr(" to the work list : ");
2002  }
2003
2004  block->set_on_work_list(true);
2005
2006  // decreasing post order sort
2007
2008  Block* prev = NULL;
2009  Block* current = _work_list;
2010  int po = block->post_order();
2011  while (current != NULL) {
2012    if (!current->has_post_order() || po > current->post_order())
2013      break;
2014    prev = current;
2015    current = current->next();
2016  }
2017  if (prev == NULL) {
2018    block->set_next(_work_list);
2019    _work_list = block;
2020  } else {
2021    block->set_next(current);
2022    prev->set_next(block);
2023  }
2024
2025  if (CITraceTypeFlow) {
2026    tty->cr();
2027  }
2028}
2029
2030// ------------------------------------------------------------------
2031// ciTypeFlow::block_at
2032//
2033// Return the block beginning at bci which has a JsrSet compatible
2034// with jsrs.
2035ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2036  // First find the right ciBlock.
2037  if (CITraceTypeFlow) {
2038    tty->print(">> Requesting block for %d/", bci);
2039    jsrs->print_on(tty);
2040    tty->cr();
2041  }
2042
2043  ciBlock* ciblk = _methodBlocks->block_containing(bci);
2044  assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2045  Block* block = get_block_for(ciblk->index(), jsrs, option);
2046
2047  assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2048
2049  if (CITraceTypeFlow) {
2050    if (block != NULL) {
2051      tty->print(">> Found block ");
2052      block->print_value_on(tty);
2053      tty->cr();
2054    } else {
2055      tty->print_cr(">> No such block.");
2056    }
2057  }
2058
2059  return block;
2060}
2061
2062// ------------------------------------------------------------------
2063// ciTypeFlow::make_jsr_record
2064//
2065// Make a JsrRecord for a given (entry, return) pair, if such a record
2066// does not already exist.
2067ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2068                                                   int return_address) {
2069  if (_jsr_records == NULL) {
2070    _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2071                                                           _jsr_count,
2072                                                           0,
2073                                                           NULL);
2074  }
2075  JsrRecord* record = NULL;
2076  int len = _jsr_records->length();
2077  for (int i = 0; i < len; i++) {
2078    JsrRecord* record = _jsr_records->at(i);
2079    if (record->entry_address() == entry_address &&
2080        record->return_address() == return_address) {
2081      return record;
2082    }
2083  }
2084
2085  record = new (arena()) JsrRecord(entry_address, return_address);
2086  _jsr_records->append(record);
2087  return record;
2088}
2089
2090// ------------------------------------------------------------------
2091// ciTypeFlow::flow_exceptions
2092//
2093// Merge the current state into all exceptional successors at the
2094// current point in the code.
2095void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2096                                 GrowableArray<ciInstanceKlass*>* exc_klasses,
2097                                 ciTypeFlow::StateVector* state) {
2098  int len = exceptions->length();
2099  assert(exc_klasses->length() == len, "must have same length");
2100  for (int i = 0; i < len; i++) {
2101    Block* block = exceptions->at(i);
2102    ciInstanceKlass* exception_klass = exc_klasses->at(i);
2103
2104    if (!exception_klass->is_loaded()) {
2105      // Do not compile any code for unloaded exception types.
2106      // Following compiler passes are responsible for doing this also.
2107      continue;
2108    }
2109
2110    if (block->meet_exception(exception_klass, state)) {
2111      // Block was modified and has PO.  Add it to the work list.
2112      if (block->has_post_order() &&
2113          !block->is_on_work_list()) {
2114        add_to_work_list(block);
2115      }
2116    }
2117  }
2118}
2119
2120// ------------------------------------------------------------------
2121// ciTypeFlow::flow_successors
2122//
2123// Merge the current state into all successors at the current point
2124// in the code.
2125void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2126                                 ciTypeFlow::StateVector* state) {
2127  int len = successors->length();
2128  for (int i = 0; i < len; i++) {
2129    Block* block = successors->at(i);
2130    if (block->meet(state)) {
2131      // Block was modified and has PO.  Add it to the work list.
2132      if (block->has_post_order() &&
2133          !block->is_on_work_list()) {
2134        add_to_work_list(block);
2135      }
2136    }
2137  }
2138}
2139
2140// ------------------------------------------------------------------
2141// ciTypeFlow::can_trap
2142//
2143// Tells if a given instruction is able to generate an exception edge.
2144bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2145  // Cf. GenerateOopMap::do_exception_edge.
2146  if (!Bytecodes::can_trap(str.cur_bc()))  return false;
2147
2148  switch (str.cur_bc()) {
2149    // %%% FIXME: ldc of Class can generate an exception
2150    case Bytecodes::_ldc:
2151    case Bytecodes::_ldc_w:
2152    case Bytecodes::_ldc2_w:
2153    case Bytecodes::_aload_0:
2154      // These bytecodes can trap for rewriting.  We need to assume that
2155      // they do not throw exceptions to make the monitor analysis work.
2156      return false;
2157
2158    case Bytecodes::_ireturn:
2159    case Bytecodes::_lreturn:
2160    case Bytecodes::_freturn:
2161    case Bytecodes::_dreturn:
2162    case Bytecodes::_areturn:
2163    case Bytecodes::_return:
2164      // We can assume the monitor stack is empty in this analysis.
2165      return false;
2166
2167    case Bytecodes::_monitorexit:
2168      // We can assume monitors are matched in this analysis.
2169      return false;
2170  }
2171
2172  return true;
2173}
2174
2175// ------------------------------------------------------------------
2176// ciTypeFlow::clone_loop_heads
2177//
2178// Clone the loop heads
2179bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2180  bool rslt = false;
2181  for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2182    lp = iter.current();
2183    Block* head = lp->head();
2184    if (lp == loop_tree_root() ||
2185        lp->is_irreducible() ||
2186        !head->is_clonable_exit(lp))
2187      continue;
2188
2189    // Avoid BoxLock merge.
2190    if (EliminateNestedLocks && head->has_monitorenter())
2191      continue;
2192
2193    // check not already cloned
2194    if (head->backedge_copy_count() != 0)
2195      continue;
2196
2197    // check _no_ shared head below us
2198    Loop* ch;
2199    for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2200    if (ch != NULL)
2201      continue;
2202
2203    // Clone head
2204    Block* new_head = head->looping_succ(lp);
2205    Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2206    // Update lp's info
2207    clone->set_loop(lp);
2208    lp->set_head(new_head);
2209    lp->set_tail(clone);
2210    // And move original head into outer loop
2211    head->set_loop(lp->parent());
2212
2213    rslt = true;
2214  }
2215  return rslt;
2216}
2217
2218// ------------------------------------------------------------------
2219// ciTypeFlow::clone_loop_head
2220//
2221// Clone lp's head and replace tail's successors with clone.
2222//
2223//  |
2224//  v
2225// head <-> body
2226//  |
2227//  v
2228// exit
2229//
2230// new_head
2231//
2232//  |
2233//  v
2234// head ----------\
2235//  |             |
2236//  |             v
2237//  |  clone <-> body
2238//  |    |
2239//  | /--/
2240//  | |
2241//  v v
2242// exit
2243//
2244ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2245  Block* head = lp->head();
2246  Block* tail = lp->tail();
2247  if (CITraceTypeFlow) {
2248    tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2249    tty->print("  for predecessor ");                tail->print_value_on(tty);
2250    tty->cr();
2251  }
2252  Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2253  assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2254
2255  assert(!clone->has_pre_order(), "just created");
2256  clone->set_next_pre_order();
2257
2258  // Insert clone after (orig) tail in reverse post order
2259  clone->set_rpo_next(tail->rpo_next());
2260  tail->set_rpo_next(clone);
2261
2262  // tail->head becomes tail->clone
2263  for (SuccIter iter(tail); !iter.done(); iter.next()) {
2264    if (iter.succ() == head) {
2265      iter.set_succ(clone);
2266    }
2267  }
2268  flow_block(tail, temp_vector, temp_set);
2269  if (head == tail) {
2270    // For self-loops, clone->head becomes clone->clone
2271    flow_block(clone, temp_vector, temp_set);
2272    for (SuccIter iter(clone); !iter.done(); iter.next()) {
2273      if (iter.succ() == head) {
2274        iter.set_succ(clone);
2275        break;
2276      }
2277    }
2278  }
2279  flow_block(clone, temp_vector, temp_set);
2280
2281  return clone;
2282}
2283
2284// ------------------------------------------------------------------
2285// ciTypeFlow::flow_block
2286//
2287// Interpret the effects of the bytecodes on the incoming state
2288// vector of a basic block.  Push the changed state to succeeding
2289// basic blocks.
2290void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2291                            ciTypeFlow::StateVector* state,
2292                            ciTypeFlow::JsrSet* jsrs) {
2293  if (CITraceTypeFlow) {
2294    tty->print("\n>> ANALYZING BLOCK : ");
2295    tty->cr();
2296    block->print_on(tty);
2297  }
2298  assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2299
2300  int start = block->start();
2301  int limit = block->limit();
2302  int control = block->control();
2303  if (control != ciBlock::fall_through_bci) {
2304    limit = control;
2305  }
2306
2307  // Grab the state from the current block.
2308  block->copy_state_into(state);
2309  state->def_locals()->clear();
2310
2311  GrowableArray<Block*>*           exceptions = block->exceptions();
2312  GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2313  bool has_exceptions = exceptions->length() > 0;
2314
2315  bool exceptions_used = false;
2316
2317  ciBytecodeStream str(method());
2318  str.reset_to_bci(start);
2319  Bytecodes::Code code;
2320  while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2321         str.cur_bci() < limit) {
2322    // Check for exceptional control flow from this point.
2323    if (has_exceptions && can_trap(str)) {
2324      flow_exceptions(exceptions, exc_klasses, state);
2325      exceptions_used = true;
2326    }
2327    // Apply the effects of the current bytecode to our state.
2328    bool res = state->apply_one_bytecode(&str);
2329
2330    // Watch for bailouts.
2331    if (failing())  return;
2332
2333    if (str.cur_bc() == Bytecodes::_monitorenter) {
2334      block->set_has_monitorenter();
2335    }
2336
2337    if (res) {
2338
2339      // We have encountered a trap.  Record it in this block.
2340      block->set_trap(state->trap_bci(), state->trap_index());
2341
2342      if (CITraceTypeFlow) {
2343        tty->print_cr(">> Found trap");
2344        block->print_on(tty);
2345      }
2346
2347      // Save set of locals defined in this block
2348      block->def_locals()->add(state->def_locals());
2349
2350      // Record (no) successors.
2351      block->successors(&str, state, jsrs);
2352
2353      assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2354
2355      // Discontinue interpretation of this Block.
2356      return;
2357    }
2358  }
2359
2360  GrowableArray<Block*>* successors = NULL;
2361  if (control != ciBlock::fall_through_bci) {
2362    // Check for exceptional control flow from this point.
2363    if (has_exceptions && can_trap(str)) {
2364      flow_exceptions(exceptions, exc_klasses, state);
2365      exceptions_used = true;
2366    }
2367
2368    // Fix the JsrSet to reflect effect of the bytecode.
2369    block->copy_jsrs_into(jsrs);
2370    jsrs->apply_control(this, &str, state);
2371
2372    // Find successor edges based on old state and new JsrSet.
2373    successors = block->successors(&str, state, jsrs);
2374
2375    // Apply the control changes to the state.
2376    state->apply_one_bytecode(&str);
2377  } else {
2378    // Fall through control
2379    successors = block->successors(&str, NULL, NULL);
2380  }
2381
2382  // Save set of locals defined in this block
2383  block->def_locals()->add(state->def_locals());
2384
2385  // Remove untaken exception paths
2386  if (!exceptions_used)
2387    exceptions->clear();
2388
2389  // Pass our state to successors.
2390  flow_successors(successors, state);
2391}
2392
2393// ------------------------------------------------------------------
2394// ciTypeFlow::PostOrderLoops::next
2395//
2396// Advance to next loop tree using a postorder, left-to-right traversal.
2397void ciTypeFlow::PostorderLoops::next() {
2398  assert(!done(), "must not be done.");
2399  if (_current->sibling() != NULL) {
2400    _current = _current->sibling();
2401    while (_current->child() != NULL) {
2402      _current = _current->child();
2403    }
2404  } else {
2405    _current = _current->parent();
2406  }
2407}
2408
2409// ------------------------------------------------------------------
2410// ciTypeFlow::PreOrderLoops::next
2411//
2412// Advance to next loop tree using a preorder, left-to-right traversal.
2413void ciTypeFlow::PreorderLoops::next() {
2414  assert(!done(), "must not be done.");
2415  if (_current->child() != NULL) {
2416    _current = _current->child();
2417  } else if (_current->sibling() != NULL) {
2418    _current = _current->sibling();
2419  } else {
2420    while (_current != _root && _current->sibling() == NULL) {
2421      _current = _current->parent();
2422    }
2423    if (_current == _root) {
2424      _current = NULL;
2425      assert(done(), "must be done.");
2426    } else {
2427      assert(_current->sibling() != NULL, "must be more to do");
2428      _current = _current->sibling();
2429    }
2430  }
2431}
2432
2433// ------------------------------------------------------------------
2434// ciTypeFlow::Loop::sorted_merge
2435//
2436// Merge the branch lp into this branch, sorting on the loop head
2437// pre_orders. Returns the leaf of the merged branch.
2438// Child and sibling pointers will be setup later.
2439// Sort is (looking from leaf towards the root)
2440//  descending on primary key: loop head's pre_order, and
2441//  ascending  on secondary key: loop tail's pre_order.
2442ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2443  Loop* leaf = this;
2444  Loop* prev = NULL;
2445  Loop* current = leaf;
2446  while (lp != NULL) {
2447    int lp_pre_order = lp->head()->pre_order();
2448    // Find insertion point for "lp"
2449    while (current != NULL) {
2450      if (current == lp)
2451        return leaf; // Already in list
2452      if (current->head()->pre_order() < lp_pre_order)
2453        break;
2454      if (current->head()->pre_order() == lp_pre_order &&
2455          current->tail()->pre_order() > lp->tail()->pre_order()) {
2456        break;
2457      }
2458      prev = current;
2459      current = current->parent();
2460    }
2461    Loop* next_lp = lp->parent(); // Save future list of items to insert
2462    // Insert lp before current
2463    lp->set_parent(current);
2464    if (prev != NULL) {
2465      prev->set_parent(lp);
2466    } else {
2467      leaf = lp;
2468    }
2469    prev = lp;     // Inserted item is new prev[ious]
2470    lp = next_lp;  // Next item to insert
2471  }
2472  return leaf;
2473}
2474
2475// ------------------------------------------------------------------
2476// ciTypeFlow::build_loop_tree
2477//
2478// Incrementally build loop tree.
2479void ciTypeFlow::build_loop_tree(Block* blk) {
2480  assert(!blk->is_post_visited(), "precondition");
2481  Loop* innermost = NULL; // merge of loop tree branches over all successors
2482
2483  for (SuccIter iter(blk); !iter.done(); iter.next()) {
2484    Loop*  lp   = NULL;
2485    Block* succ = iter.succ();
2486    if (!succ->is_post_visited()) {
2487      // Found backedge since predecessor post visited, but successor is not
2488      assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2489
2490      // Create a LoopNode to mark this loop.
2491      lp = new (arena()) Loop(succ, blk);
2492      if (succ->loop() == NULL)
2493        succ->set_loop(lp);
2494      // succ->loop will be updated to innermost loop on a later call, when blk==succ
2495
2496    } else {  // Nested loop
2497      lp = succ->loop();
2498
2499      // If succ is loop head, find outer loop.
2500      while (lp != NULL && lp->head() == succ) {
2501        lp = lp->parent();
2502      }
2503      if (lp == NULL) {
2504        // Infinite loop, it's parent is the root
2505        lp = loop_tree_root();
2506      }
2507    }
2508
2509    // Check for irreducible loop.
2510    // Successor has already been visited. If the successor's loop head
2511    // has already been post-visited, then this is another entry into the loop.
2512    while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2513      _has_irreducible_entry = true;
2514      lp->set_irreducible(succ);
2515      if (!succ->is_on_work_list()) {
2516        // Assume irreducible entries need more data flow
2517        add_to_work_list(succ);
2518      }
2519      Loop* plp = lp->parent();
2520      if (plp == NULL) {
2521        // This only happens for some irreducible cases.  The parent
2522        // will be updated during a later pass.
2523        break;
2524      }
2525      lp = plp;
2526    }
2527
2528    // Merge loop tree branch for all successors.
2529    innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2530
2531  } // end loop
2532
2533  if (innermost == NULL) {
2534    assert(blk->successors()->length() == 0, "CFG exit");
2535    blk->set_loop(loop_tree_root());
2536  } else if (innermost->head() == blk) {
2537    // If loop header, complete the tree pointers
2538    if (blk->loop() != innermost) {
2539#if ASSERT
2540      assert(blk->loop()->head() == innermost->head(), "same head");
2541      Loop* dl;
2542      for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2543      assert(dl == blk->loop(), "blk->loop() already in innermost list");
2544#endif
2545      blk->set_loop(innermost);
2546    }
2547    innermost->def_locals()->add(blk->def_locals());
2548    Loop* l = innermost;
2549    Loop* p = l->parent();
2550    while (p && l->head() == blk) {
2551      l->set_sibling(p->child());  // Put self on parents 'next child'
2552      p->set_child(l);             // Make self the first child of parent
2553      p->def_locals()->add(l->def_locals());
2554      l = p;                       // Walk up the parent chain
2555      p = l->parent();
2556    }
2557  } else {
2558    blk->set_loop(innermost);
2559    innermost->def_locals()->add(blk->def_locals());
2560  }
2561}
2562
2563// ------------------------------------------------------------------
2564// ciTypeFlow::Loop::contains
2565//
2566// Returns true if lp is nested loop.
2567bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2568  assert(lp != NULL, "");
2569  if (this == lp || head() == lp->head()) return true;
2570  int depth1 = depth();
2571  int depth2 = lp->depth();
2572  if (depth1 > depth2)
2573    return false;
2574  while (depth1 < depth2) {
2575    depth2--;
2576    lp = lp->parent();
2577  }
2578  return this == lp;
2579}
2580
2581// ------------------------------------------------------------------
2582// ciTypeFlow::Loop::depth
2583//
2584// Loop depth
2585int ciTypeFlow::Loop::depth() const {
2586  int dp = 0;
2587  for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2588    dp++;
2589  return dp;
2590}
2591
2592#ifndef PRODUCT
2593// ------------------------------------------------------------------
2594// ciTypeFlow::Loop::print
2595void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2596  for (int i = 0; i < indent; i++) st->print(" ");
2597  st->print("%d<-%d %s",
2598            is_root() ? 0 : this->head()->pre_order(),
2599            is_root() ? 0 : this->tail()->pre_order(),
2600            is_irreducible()?" irr":"");
2601  st->print(" defs: ");
2602  def_locals()->print_on(st, _head->outer()->method()->max_locals());
2603  st->cr();
2604  for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2605    ch->print(st, indent+2);
2606}
2607#endif
2608
2609// ------------------------------------------------------------------
2610// ciTypeFlow::df_flow_types
2611//
2612// Perform the depth first type flow analysis. Helper for flow_types.
2613void ciTypeFlow::df_flow_types(Block* start,
2614                               bool do_flow,
2615                               StateVector* temp_vector,
2616                               JsrSet* temp_set) {
2617  int dft_len = 100;
2618  GrowableArray<Block*> stk(dft_len);
2619
2620  ciBlock* dummy = _methodBlocks->make_dummy_block();
2621  JsrSet* root_set = new JsrSet(NULL, 0);
2622  Block* root_head = new (arena()) Block(this, dummy, root_set);
2623  Block* root_tail = new (arena()) Block(this, dummy, root_set);
2624  root_head->set_pre_order(0);
2625  root_head->set_post_order(0);
2626  root_tail->set_pre_order(max_jint);
2627  root_tail->set_post_order(max_jint);
2628  set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2629
2630  stk.push(start);
2631
2632  _next_pre_order = 0;  // initialize pre_order counter
2633  _rpo_list = NULL;
2634  int next_po = 0;      // initialize post_order counter
2635
2636  // Compute RPO and the control flow graph
2637  int size;
2638  while ((size = stk.length()) > 0) {
2639    Block* blk = stk.top(); // Leave node on stack
2640    if (!blk->is_visited()) {
2641      // forward arc in graph
2642      assert (!blk->has_pre_order(), "");
2643      blk->set_next_pre_order();
2644
2645      if (_next_pre_order >= MaxNodeLimit / 2) {
2646        // Too many basic blocks.  Bail out.
2647        // This can happen when try/finally constructs are nested to depth N,
2648        // and there is O(2**N) cloning of jsr bodies.  See bug 4697245!
2649        // "MaxNodeLimit / 2" is used because probably the parser will
2650        // generate at least twice that many nodes and bail out.
2651        record_failure("too many basic blocks");
2652        return;
2653      }
2654      if (do_flow) {
2655        flow_block(blk, temp_vector, temp_set);
2656        if (failing()) return; // Watch for bailouts.
2657      }
2658    } else if (!blk->is_post_visited()) {
2659      // cross or back arc
2660      for (SuccIter iter(blk); !iter.done(); iter.next()) {
2661        Block* succ = iter.succ();
2662        if (!succ->is_visited()) {
2663          stk.push(succ);
2664        }
2665      }
2666      if (stk.length() == size) {
2667        // There were no additional children, post visit node now
2668        stk.pop(); // Remove node from stack
2669
2670        build_loop_tree(blk);
2671        blk->set_post_order(next_po++);   // Assign post order
2672        prepend_to_rpo_list(blk);
2673        assert(blk->is_post_visited(), "");
2674
2675        if (blk->is_loop_head() && !blk->is_on_work_list()) {
2676          // Assume loop heads need more data flow
2677          add_to_work_list(blk);
2678        }
2679      }
2680    } else {
2681      stk.pop(); // Remove post-visited node from stack
2682    }
2683  }
2684}
2685
2686// ------------------------------------------------------------------
2687// ciTypeFlow::flow_types
2688//
2689// Perform the type flow analysis, creating and cloning Blocks as
2690// necessary.
2691void ciTypeFlow::flow_types() {
2692  ResourceMark rm;
2693  StateVector* temp_vector = new StateVector(this);
2694  JsrSet* temp_set = new JsrSet(NULL, 16);
2695
2696  // Create the method entry block.
2697  Block* start = block_at(start_bci(), temp_set);
2698
2699  // Load the initial state into it.
2700  const StateVector* start_state = get_start_state();
2701  if (failing())  return;
2702  start->meet(start_state);
2703
2704  // Depth first visit
2705  df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2706
2707  if (failing())  return;
2708  assert(_rpo_list == start, "must be start");
2709
2710  // Any loops found?
2711  if (loop_tree_root()->child() != NULL &&
2712      env()->comp_level() >= CompLevel_full_optimization) {
2713      // Loop optimizations are not performed on Tier1 compiles.
2714
2715    bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2716
2717    // If some loop heads were cloned, recompute postorder and loop tree
2718    if (changed) {
2719      loop_tree_root()->set_child(NULL);
2720      for (Block* blk = _rpo_list; blk != NULL;) {
2721        Block* next = blk->rpo_next();
2722        blk->df_init();
2723        blk = next;
2724      }
2725      df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2726    }
2727  }
2728
2729  if (CITraceTypeFlow) {
2730    tty->print_cr("\nLoop tree");
2731    loop_tree_root()->print();
2732  }
2733
2734  // Continue flow analysis until fixed point reached
2735
2736  debug_only(int max_block = _next_pre_order;)
2737
2738  while (!work_list_empty()) {
2739    Block* blk = work_list_next();
2740    assert (blk->has_post_order(), "post order assigned above");
2741
2742    flow_block(blk, temp_vector, temp_set);
2743
2744    assert (max_block == _next_pre_order, "no new blocks");
2745    assert (!failing(), "no more bailouts");
2746  }
2747}
2748
2749// ------------------------------------------------------------------
2750// ciTypeFlow::map_blocks
2751//
2752// Create the block map, which indexes blocks in reverse post-order.
2753void ciTypeFlow::map_blocks() {
2754  assert(_block_map == NULL, "single initialization");
2755  int block_ct = _next_pre_order;
2756  _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2757  assert(block_ct == block_count(), "");
2758
2759  Block* blk = _rpo_list;
2760  for (int m = 0; m < block_ct; m++) {
2761    int rpo = blk->rpo();
2762    assert(rpo == m, "should be sequential");
2763    _block_map[rpo] = blk;
2764    blk = blk->rpo_next();
2765  }
2766  assert(blk == NULL, "should be done");
2767
2768  for (int j = 0; j < block_ct; j++) {
2769    assert(_block_map[j] != NULL, "must not drop any blocks");
2770    Block* block = _block_map[j];
2771    // Remove dead blocks from successor lists:
2772    for (int e = 0; e <= 1; e++) {
2773      GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2774      for (int k = 0; k < l->length(); k++) {
2775        Block* s = l->at(k);
2776        if (!s->has_post_order()) {
2777          if (CITraceTypeFlow) {
2778            tty->print("Removing dead %s successor of #%d: ", (e? "exceptional":  "normal"), block->pre_order());
2779            s->print_value_on(tty);
2780            tty->cr();
2781          }
2782          l->remove(s);
2783          --k;
2784        }
2785      }
2786    }
2787  }
2788}
2789
2790// ------------------------------------------------------------------
2791// ciTypeFlow::get_block_for
2792//
2793// Find a block with this ciBlock which has a compatible JsrSet.
2794// If no such block exists, create it, unless the option is no_create.
2795// If the option is create_backedge_copy, always create a fresh backedge copy.
2796ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2797  Arena* a = arena();
2798  GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2799  if (blocks == NULL) {
2800    // Query only?
2801    if (option == no_create)  return NULL;
2802
2803    // Allocate the growable array.
2804    blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2805    _idx_to_blocklist[ciBlockIndex] = blocks;
2806  }
2807
2808  if (option != create_backedge_copy) {
2809    int len = blocks->length();
2810    for (int i = 0; i < len; i++) {
2811      Block* block = blocks->at(i);
2812      if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2813        return block;
2814      }
2815    }
2816  }
2817
2818  // Query only?
2819  if (option == no_create)  return NULL;
2820
2821  // We did not find a compatible block.  Create one.
2822  Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2823  if (option == create_backedge_copy)  new_block->set_backedge_copy(true);
2824  blocks->append(new_block);
2825  return new_block;
2826}
2827
2828// ------------------------------------------------------------------
2829// ciTypeFlow::backedge_copy_count
2830//
2831int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2832  GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2833
2834  if (blocks == NULL) {
2835    return 0;
2836  }
2837
2838  int count = 0;
2839  int len = blocks->length();
2840  for (int i = 0; i < len; i++) {
2841    Block* block = blocks->at(i);
2842    if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2843      count++;
2844    }
2845  }
2846
2847  return count;
2848}
2849
2850// ------------------------------------------------------------------
2851// ciTypeFlow::do_flow
2852//
2853// Perform type inference flow analysis.
2854void ciTypeFlow::do_flow() {
2855  if (CITraceTypeFlow) {
2856    tty->print_cr("\nPerforming flow analysis on method");
2857    method()->print();
2858    if (is_osr_flow())  tty->print(" at OSR bci %d", start_bci());
2859    tty->cr();
2860    method()->print_codes();
2861  }
2862  if (CITraceTypeFlow) {
2863    tty->print_cr("Initial CI Blocks");
2864    print_on(tty);
2865  }
2866  flow_types();
2867  // Watch for bailouts.
2868  if (failing()) {
2869    return;
2870  }
2871
2872  map_blocks();
2873
2874  if (CIPrintTypeFlow || CITraceTypeFlow) {
2875    rpo_print_on(tty);
2876  }
2877}
2878
2879// ------------------------------------------------------------------
2880// ciTypeFlow::record_failure()
2881// The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
2882// This is required because there is not a 1-1 relation between the ciEnv and
2883// the TypeFlow passes within a compilation task.  For example, if the compiler
2884// is considering inlining a method, it will request a TypeFlow.  If that fails,
2885// the compilation as a whole may continue without the inlining.  Some TypeFlow
2886// requests are not optional; if they fail the requestor is responsible for
2887// copying the failure reason up to the ciEnv.  (See Parse::Parse.)
2888void ciTypeFlow::record_failure(const char* reason) {
2889  if (env()->log() != NULL) {
2890    env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
2891  }
2892  if (_failure_reason == NULL) {
2893    // Record the first failure reason.
2894    _failure_reason = reason;
2895  }
2896}
2897
2898#ifndef PRODUCT
2899// ------------------------------------------------------------------
2900// ciTypeFlow::print_on
2901void ciTypeFlow::print_on(outputStream* st) const {
2902  // Walk through CI blocks
2903  st->print_cr("********************************************************");
2904  st->print   ("TypeFlow for ");
2905  method()->name()->print_symbol_on(st);
2906  int limit_bci = code_size();
2907  st->print_cr("  %d bytes", limit_bci);
2908  ciMethodBlocks  *mblks = _methodBlocks;
2909  ciBlock* current = NULL;
2910  for (int bci = 0; bci < limit_bci; bci++) {
2911    ciBlock* blk = mblks->block_containing(bci);
2912    if (blk != NULL && blk != current) {
2913      current = blk;
2914      current->print_on(st);
2915
2916      GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
2917      int num_blocks = (blocks == NULL) ? 0 : blocks->length();
2918
2919      if (num_blocks == 0) {
2920        st->print_cr("  No Blocks");
2921      } else {
2922        for (int i = 0; i < num_blocks; i++) {
2923          Block* block = blocks->at(i);
2924          block->print_on(st);
2925        }
2926      }
2927      st->print_cr("--------------------------------------------------------");
2928      st->cr();
2929    }
2930  }
2931  st->print_cr("********************************************************");
2932  st->cr();
2933}
2934
2935void ciTypeFlow::rpo_print_on(outputStream* st) const {
2936  st->print_cr("********************************************************");
2937  st->print   ("TypeFlow for ");
2938  method()->name()->print_symbol_on(st);
2939  int limit_bci = code_size();
2940  st->print_cr("  %d bytes", limit_bci);
2941  for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
2942    blk->print_on(st);
2943    st->print_cr("--------------------------------------------------------");
2944    st->cr();
2945  }
2946  st->print_cr("********************************************************");
2947  st->cr();
2948}
2949#endif
2950