ciTypeFlow.cpp revision 1879:f95d63e2154a 
1/*
2 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "ci/ciConstant.hpp"
27#include "ci/ciField.hpp"
28#include "ci/ciMethod.hpp"
29#include "ci/ciMethodData.hpp"
30#include "ci/ciObjArrayKlass.hpp"
31#include "ci/ciStreams.hpp"
32#include "ci/ciTypeArrayKlass.hpp"
33#include "ci/ciTypeFlow.hpp"
34#include "compiler/compileLog.hpp"
35#include "interpreter/bytecode.hpp"
36#include "interpreter/bytecodes.hpp"
37#include "memory/allocation.inline.hpp"
38#include "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  ciMethod* method = str->get_method(will_link);
649  if (!will_link) {
650    // We weren't able to find the method.
651    if (str->cur_bc() == Bytecodes::_invokedynamic) {
652      trap(str, NULL,
653           Deoptimization::make_trap_request
654           (Deoptimization::Reason_uninitialized,
655            Deoptimization::Action_reinterpret));
656    } else {
657      ciKlass* unloaded_holder = method->holder();
658      trap(str, unloaded_holder, str->get_method_holder_index());
659    }
660  } else {
661    ciSignature* signature = method->signature();
662    ciSignatureStream sigstr(signature);
663    int arg_size = signature->size();
664    int stack_base = stack_size() - arg_size;
665    int i = 0;
666    for( ; !sigstr.at_return_type(); sigstr.next()) {
667      ciType* type = sigstr.type();
668      ciType* stack_type = type_at(stack(stack_base + i++));
669      // Do I want to check this type?
670      // assert(stack_type->is_subtype_of(type), "bad type for field value");
671      if (type->is_two_word()) {
672        ciType* stack_type2 = type_at(stack(stack_base + i++));
673        assert(stack_type2->equals(half_type(type)), "must be 2nd half");
674      }
675    }
676    assert(arg_size == i, "must match");
677    for (int j = 0; j < arg_size; j++) {
678      pop();
679    }
680    if (has_receiver) {
681      // Check this?
682      pop_object();
683    }
684    assert(!sigstr.is_done(), "must have return type");
685    ciType* return_type = sigstr.type();
686    if (!return_type->is_void()) {
687      if (!return_type->is_loaded()) {
688        // As in do_getstatic(), generally speaking, we need the return type to
689        // be loaded if we are to do anything interesting with its value.
690        // We used to do this:  trap(str, str->get_method_signature_index());
691        //
692        // We do not trap here since execution can get past this invoke if
693        // the return value is null.  As long as the value is null, the class
694        // does not need to be loaded!  The compiler must assume that
695        // the value of the unloaded class reference is null; if the code
696        // ever sees a non-null value, loading has occurred.
697        //
698        // See do_getstatic() for similar explanation, as well as bug 4684993.
699        do_null_assert(return_type->as_klass());
700      } else {
701        push_translate(return_type);
702      }
703    }
704  }
705}
706
707// ------------------------------------------------------------------
708// ciTypeFlow::StateVector::do_jsr
709void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
710  push(ciReturnAddress::make(str->next_bci()));
711}
712
713// ------------------------------------------------------------------
714// ciTypeFlow::StateVector::do_ldc
715void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
716  ciConstant con = str->get_constant();
717  BasicType basic_type = con.basic_type();
718  if (basic_type == T_ILLEGAL) {
719    // OutOfMemoryError in the CI while loading constant
720    push_null();
721    outer()->record_failure("ldc did not link");
722    return;
723  }
724  if (basic_type == T_OBJECT || basic_type == T_ARRAY) {
725    ciObject* obj = con.as_object();
726    if (obj->is_null_object()) {
727      push_null();
728    } else {
729      assert(!obj->is_klass(), "must be java_mirror of klass");
730      push_object(obj->klass());
731    }
732  } else {
733    push_translate(ciType::make(basic_type));
734  }
735}
736
737// ------------------------------------------------------------------
738// ciTypeFlow::StateVector::do_multianewarray
739void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
740  int dimensions = str->get_dimensions();
741  bool will_link;
742  ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
743  if (!will_link) {
744    trap(str, array_klass, str->get_klass_index());
745  } else {
746    for (int i = 0; i < dimensions; i++) {
747      pop_int();
748    }
749    push_object(array_klass);
750  }
751}
752
753// ------------------------------------------------------------------
754// ciTypeFlow::StateVector::do_new
755void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
756  bool will_link;
757  ciKlass* klass = str->get_klass(will_link);
758  if (!will_link || str->is_unresolved_klass()) {
759    trap(str, klass, str->get_klass_index());
760  } else {
761    push_object(klass);
762  }
763}
764
765// ------------------------------------------------------------------
766// ciTypeFlow::StateVector::do_newarray
767void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
768  pop_int();
769  ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
770  push_object(klass);
771}
772
773// ------------------------------------------------------------------
774// ciTypeFlow::StateVector::do_putfield
775void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
776  do_putstatic(str);
777  if (_trap_bci != -1)  return;  // unloaded field holder, etc.
778  // could add assert here for type of object.
779  pop_object();
780}
781
782// ------------------------------------------------------------------
783// ciTypeFlow::StateVector::do_putstatic
784void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
785  bool will_link;
786  ciField* field = str->get_field(will_link);
787  if (!will_link) {
788    trap(str, field->holder(), str->get_field_holder_index());
789  } else {
790    ciType* field_type = field->type();
791    ciType* type = pop_value();
792    // Do I want to check this type?
793    //      assert(type->is_subtype_of(field_type), "bad type for field value");
794    if (field_type->is_two_word()) {
795      ciType* type2 = pop_value();
796      assert(type2->is_two_word(), "must be 2nd half");
797      assert(type == half_type(type2), "must be 2nd half");
798    }
799  }
800}
801
802// ------------------------------------------------------------------
803// ciTypeFlow::StateVector::do_ret
804void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
805  Cell index = local(str->get_index());
806
807  ciType* address = type_at(index);
808  assert(address->is_return_address(), "bad return address");
809  set_type_at(index, bottom_type());
810}
811
812// ------------------------------------------------------------------
813// ciTypeFlow::StateVector::trap
814//
815// Stop interpretation of this path with a trap.
816void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
817  _trap_bci = str->cur_bci();
818  _trap_index = index;
819
820  // Log information about this trap:
821  CompileLog* log = outer()->env()->log();
822  if (log != NULL) {
823    int mid = log->identify(outer()->method());
824    int kid = (klass == NULL)? -1: log->identify(klass);
825    log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
826    char buf[100];
827    log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
828                                                          index));
829    if (kid >= 0)
830      log->print(" klass='%d'", kid);
831    log->end_elem();
832  }
833}
834
835// ------------------------------------------------------------------
836// ciTypeFlow::StateVector::do_null_assert
837// Corresponds to graphKit::do_null_assert.
838void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
839  if (unloaded_klass->is_loaded()) {
840    // We failed to link, but we can still compute with this class,
841    // since it is loaded somewhere.  The compiler will uncommon_trap
842    // if the object is not null, but the typeflow pass can not assume
843    // that the object will be null, otherwise it may incorrectly tell
844    // the parser that an object is known to be null. 4761344, 4807707
845    push_object(unloaded_klass);
846  } else {
847    // The class is not loaded anywhere.  It is safe to model the
848    // null in the typestates, because we can compile in a null check
849    // which will deoptimize us if someone manages to load the
850    // class later.
851    push_null();
852  }
853}
854
855
856// ------------------------------------------------------------------
857// ciTypeFlow::StateVector::apply_one_bytecode
858//
859// Apply the effect of one bytecode to this StateVector
860bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
861  _trap_bci = -1;
862  _trap_index = 0;
863
864  if (CITraceTypeFlow) {
865    tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
866                  Bytecodes::name(str->cur_bc()));
867  }
868
869  switch(str->cur_bc()) {
870  case Bytecodes::_aaload: do_aaload(str);                       break;
871
872  case Bytecodes::_aastore:
873    {
874      pop_object();
875      pop_int();
876      pop_objArray();
877      break;
878    }
879  case Bytecodes::_aconst_null:
880    {
881      push_null();
882      break;
883    }
884  case Bytecodes::_aload:   load_local_object(str->get_index());    break;
885  case Bytecodes::_aload_0: load_local_object(0);                   break;
886  case Bytecodes::_aload_1: load_local_object(1);                   break;
887  case Bytecodes::_aload_2: load_local_object(2);                   break;
888  case Bytecodes::_aload_3: load_local_object(3);                   break;
889
890  case Bytecodes::_anewarray:
891    {
892      pop_int();
893      bool will_link;
894      ciKlass* element_klass = str->get_klass(will_link);
895      if (!will_link) {
896        trap(str, element_klass, str->get_klass_index());
897      } else {
898        push_object(ciObjArrayKlass::make(element_klass));
899      }
900      break;
901    }
902  case Bytecodes::_areturn:
903  case Bytecodes::_ifnonnull:
904  case Bytecodes::_ifnull:
905    {
906      pop_object();
907      break;
908    }
909  case Bytecodes::_monitorenter:
910    {
911      pop_object();
912      set_monitor_count(monitor_count() + 1);
913      break;
914    }
915  case Bytecodes::_monitorexit:
916    {
917      pop_object();
918      assert(monitor_count() > 0, "must be a monitor to exit from");
919      set_monitor_count(monitor_count() - 1);
920      break;
921    }
922  case Bytecodes::_arraylength:
923    {
924      pop_array();
925      push_int();
926      break;
927    }
928  case Bytecodes::_astore:   store_local_object(str->get_index());  break;
929  case Bytecodes::_astore_0: store_local_object(0);                 break;
930  case Bytecodes::_astore_1: store_local_object(1);                 break;
931  case Bytecodes::_astore_2: store_local_object(2);                 break;
932  case Bytecodes::_astore_3: store_local_object(3);                 break;
933
934  case Bytecodes::_athrow:
935    {
936      NEEDS_CLEANUP;
937      pop_object();
938      break;
939    }
940  case Bytecodes::_baload:
941  case Bytecodes::_caload:
942  case Bytecodes::_iaload:
943  case Bytecodes::_saload:
944    {
945      pop_int();
946      ciTypeArrayKlass* array_klass = pop_typeArray();
947      // Put assert here for right type?
948      push_int();
949      break;
950    }
951  case Bytecodes::_bastore:
952  case Bytecodes::_castore:
953  case Bytecodes::_iastore:
954  case Bytecodes::_sastore:
955    {
956      pop_int();
957      pop_int();
958      pop_typeArray();
959      // assert here?
960      break;
961    }
962  case Bytecodes::_bipush:
963  case Bytecodes::_iconst_m1:
964  case Bytecodes::_iconst_0:
965  case Bytecodes::_iconst_1:
966  case Bytecodes::_iconst_2:
967  case Bytecodes::_iconst_3:
968  case Bytecodes::_iconst_4:
969  case Bytecodes::_iconst_5:
970  case Bytecodes::_sipush:
971    {
972      push_int();
973      break;
974    }
975  case Bytecodes::_checkcast: do_checkcast(str);                  break;
976
977  case Bytecodes::_d2f:
978    {
979      pop_double();
980      push_float();
981      break;
982    }
983  case Bytecodes::_d2i:
984    {
985      pop_double();
986      push_int();
987      break;
988    }
989  case Bytecodes::_d2l:
990    {
991      pop_double();
992      push_long();
993      break;
994    }
995  case Bytecodes::_dadd:
996  case Bytecodes::_ddiv:
997  case Bytecodes::_dmul:
998  case Bytecodes::_drem:
999  case Bytecodes::_dsub:
1000    {
1001      pop_double();
1002      pop_double();
1003      push_double();
1004      break;
1005    }
1006  case Bytecodes::_daload:
1007    {
1008      pop_int();
1009      ciTypeArrayKlass* array_klass = pop_typeArray();
1010      // Put assert here for right type?
1011      push_double();
1012      break;
1013    }
1014  case Bytecodes::_dastore:
1015    {
1016      pop_double();
1017      pop_int();
1018      pop_typeArray();
1019      // assert here?
1020      break;
1021    }
1022  case Bytecodes::_dcmpg:
1023  case Bytecodes::_dcmpl:
1024    {
1025      pop_double();
1026      pop_double();
1027      push_int();
1028      break;
1029    }
1030  case Bytecodes::_dconst_0:
1031  case Bytecodes::_dconst_1:
1032    {
1033      push_double();
1034      break;
1035    }
1036  case Bytecodes::_dload:   load_local_double(str->get_index());    break;
1037  case Bytecodes::_dload_0: load_local_double(0);                   break;
1038  case Bytecodes::_dload_1: load_local_double(1);                   break;
1039  case Bytecodes::_dload_2: load_local_double(2);                   break;
1040  case Bytecodes::_dload_3: load_local_double(3);                   break;
1041
1042  case Bytecodes::_dneg:
1043    {
1044      pop_double();
1045      push_double();
1046      break;
1047    }
1048  case Bytecodes::_dreturn:
1049    {
1050      pop_double();
1051      break;
1052    }
1053  case Bytecodes::_dstore:   store_local_double(str->get_index());  break;
1054  case Bytecodes::_dstore_0: store_local_double(0);                 break;
1055  case Bytecodes::_dstore_1: store_local_double(1);                 break;
1056  case Bytecodes::_dstore_2: store_local_double(2);                 break;
1057  case Bytecodes::_dstore_3: store_local_double(3);                 break;
1058
1059  case Bytecodes::_dup:
1060    {
1061      push(type_at_tos());
1062      break;
1063    }
1064  case Bytecodes::_dup_x1:
1065    {
1066      ciType* value1 = pop_value();
1067      ciType* value2 = pop_value();
1068      push(value1);
1069      push(value2);
1070      push(value1);
1071      break;
1072    }
1073  case Bytecodes::_dup_x2:
1074    {
1075      ciType* value1 = pop_value();
1076      ciType* value2 = pop_value();
1077      ciType* value3 = pop_value();
1078      push(value1);
1079      push(value3);
1080      push(value2);
1081      push(value1);
1082      break;
1083    }
1084  case Bytecodes::_dup2:
1085    {
1086      ciType* value1 = pop_value();
1087      ciType* value2 = pop_value();
1088      push(value2);
1089      push(value1);
1090      push(value2);
1091      push(value1);
1092      break;
1093    }
1094  case Bytecodes::_dup2_x1:
1095    {
1096      ciType* value1 = pop_value();
1097      ciType* value2 = pop_value();
1098      ciType* value3 = pop_value();
1099      push(value2);
1100      push(value1);
1101      push(value3);
1102      push(value2);
1103      push(value1);
1104      break;
1105    }
1106  case Bytecodes::_dup2_x2:
1107    {
1108      ciType* value1 = pop_value();
1109      ciType* value2 = pop_value();
1110      ciType* value3 = pop_value();
1111      ciType* value4 = pop_value();
1112      push(value2);
1113      push(value1);
1114      push(value4);
1115      push(value3);
1116      push(value2);
1117      push(value1);
1118      break;
1119    }
1120  case Bytecodes::_f2d:
1121    {
1122      pop_float();
1123      push_double();
1124      break;
1125    }
1126  case Bytecodes::_f2i:
1127    {
1128      pop_float();
1129      push_int();
1130      break;
1131    }
1132  case Bytecodes::_f2l:
1133    {
1134      pop_float();
1135      push_long();
1136      break;
1137    }
1138  case Bytecodes::_fadd:
1139  case Bytecodes::_fdiv:
1140  case Bytecodes::_fmul:
1141  case Bytecodes::_frem:
1142  case Bytecodes::_fsub:
1143    {
1144      pop_float();
1145      pop_float();
1146      push_float();
1147      break;
1148    }
1149  case Bytecodes::_faload:
1150    {
1151      pop_int();
1152      ciTypeArrayKlass* array_klass = pop_typeArray();
1153      // Put assert here.
1154      push_float();
1155      break;
1156    }
1157  case Bytecodes::_fastore:
1158    {
1159      pop_float();
1160      pop_int();
1161      ciTypeArrayKlass* array_klass = pop_typeArray();
1162      // Put assert here.
1163      break;
1164    }
1165  case Bytecodes::_fcmpg:
1166  case Bytecodes::_fcmpl:
1167    {
1168      pop_float();
1169      pop_float();
1170      push_int();
1171      break;
1172    }
1173  case Bytecodes::_fconst_0:
1174  case Bytecodes::_fconst_1:
1175  case Bytecodes::_fconst_2:
1176    {
1177      push_float();
1178      break;
1179    }
1180  case Bytecodes::_fload:   load_local_float(str->get_index());     break;
1181  case Bytecodes::_fload_0: load_local_float(0);                    break;
1182  case Bytecodes::_fload_1: load_local_float(1);                    break;
1183  case Bytecodes::_fload_2: load_local_float(2);                    break;
1184  case Bytecodes::_fload_3: load_local_float(3);                    break;
1185
1186  case Bytecodes::_fneg:
1187    {
1188      pop_float();
1189      push_float();
1190      break;
1191    }
1192  case Bytecodes::_freturn:
1193    {
1194      pop_float();
1195      break;
1196    }
1197  case Bytecodes::_fstore:    store_local_float(str->get_index());   break;
1198  case Bytecodes::_fstore_0:  store_local_float(0);                  break;
1199  case Bytecodes::_fstore_1:  store_local_float(1);                  break;
1200  case Bytecodes::_fstore_2:  store_local_float(2);                  break;
1201  case Bytecodes::_fstore_3:  store_local_float(3);                  break;
1202
1203  case Bytecodes::_getfield:  do_getfield(str);                      break;
1204  case Bytecodes::_getstatic: do_getstatic(str);                     break;
1205
1206  case Bytecodes::_goto:
1207  case Bytecodes::_goto_w:
1208  case Bytecodes::_nop:
1209  case Bytecodes::_return:
1210    {
1211      // do nothing.
1212      break;
1213    }
1214  case Bytecodes::_i2b:
1215  case Bytecodes::_i2c:
1216  case Bytecodes::_i2s:
1217  case Bytecodes::_ineg:
1218    {
1219      pop_int();
1220      push_int();
1221      break;
1222    }
1223  case Bytecodes::_i2d:
1224    {
1225      pop_int();
1226      push_double();
1227      break;
1228    }
1229  case Bytecodes::_i2f:
1230    {
1231      pop_int();
1232      push_float();
1233      break;
1234    }
1235  case Bytecodes::_i2l:
1236    {
1237      pop_int();
1238      push_long();
1239      break;
1240    }
1241  case Bytecodes::_iadd:
1242  case Bytecodes::_iand:
1243  case Bytecodes::_idiv:
1244  case Bytecodes::_imul:
1245  case Bytecodes::_ior:
1246  case Bytecodes::_irem:
1247  case Bytecodes::_ishl:
1248  case Bytecodes::_ishr:
1249  case Bytecodes::_isub:
1250  case Bytecodes::_iushr:
1251  case Bytecodes::_ixor:
1252    {
1253      pop_int();
1254      pop_int();
1255      push_int();
1256      break;
1257    }
1258  case Bytecodes::_if_acmpeq:
1259  case Bytecodes::_if_acmpne:
1260    {
1261      pop_object();
1262      pop_object();
1263      break;
1264    }
1265  case Bytecodes::_if_icmpeq:
1266  case Bytecodes::_if_icmpge:
1267  case Bytecodes::_if_icmpgt:
1268  case Bytecodes::_if_icmple:
1269  case Bytecodes::_if_icmplt:
1270  case Bytecodes::_if_icmpne:
1271    {
1272      pop_int();
1273      pop_int();
1274      break;
1275    }
1276  case Bytecodes::_ifeq:
1277  case Bytecodes::_ifle:
1278  case Bytecodes::_iflt:
1279  case Bytecodes::_ifge:
1280  case Bytecodes::_ifgt:
1281  case Bytecodes::_ifne:
1282  case Bytecodes::_ireturn:
1283  case Bytecodes::_lookupswitch:
1284  case Bytecodes::_tableswitch:
1285    {
1286      pop_int();
1287      break;
1288    }
1289  case Bytecodes::_iinc:
1290    {
1291      int lnum = str->get_index();
1292      check_int(local(lnum));
1293      store_to_local(lnum);
1294      break;
1295    }
1296  case Bytecodes::_iload:   load_local_int(str->get_index()); break;
1297  case Bytecodes::_iload_0: load_local_int(0);                      break;
1298  case Bytecodes::_iload_1: load_local_int(1);                      break;
1299  case Bytecodes::_iload_2: load_local_int(2);                      break;
1300  case Bytecodes::_iload_3: load_local_int(3);                      break;
1301
1302  case Bytecodes::_instanceof:
1303    {
1304      // Check for uncommon trap:
1305      do_checkcast(str);
1306      pop_object();
1307      push_int();
1308      break;
1309    }
1310  case Bytecodes::_invokeinterface: do_invoke(str, true);           break;
1311  case Bytecodes::_invokespecial:   do_invoke(str, true);           break;
1312  case Bytecodes::_invokestatic:    do_invoke(str, false);          break;
1313  case Bytecodes::_invokevirtual:   do_invoke(str, true);           break;
1314  case Bytecodes::_invokedynamic:   do_invoke(str, false);          break;
1315
1316  case Bytecodes::_istore:   store_local_int(str->get_index());     break;
1317  case Bytecodes::_istore_0: store_local_int(0);                    break;
1318  case Bytecodes::_istore_1: store_local_int(1);                    break;
1319  case Bytecodes::_istore_2: store_local_int(2);                    break;
1320  case Bytecodes::_istore_3: store_local_int(3);                    break;
1321
1322  case Bytecodes::_jsr:
1323  case Bytecodes::_jsr_w: do_jsr(str);                              break;
1324
1325  case Bytecodes::_l2d:
1326    {
1327      pop_long();
1328      push_double();
1329      break;
1330    }
1331  case Bytecodes::_l2f:
1332    {
1333      pop_long();
1334      push_float();
1335      break;
1336    }
1337  case Bytecodes::_l2i:
1338    {
1339      pop_long();
1340      push_int();
1341      break;
1342    }
1343  case Bytecodes::_ladd:
1344  case Bytecodes::_land:
1345  case Bytecodes::_ldiv:
1346  case Bytecodes::_lmul:
1347  case Bytecodes::_lor:
1348  case Bytecodes::_lrem:
1349  case Bytecodes::_lsub:
1350  case Bytecodes::_lxor:
1351    {
1352      pop_long();
1353      pop_long();
1354      push_long();
1355      break;
1356    }
1357  case Bytecodes::_laload:
1358    {
1359      pop_int();
1360      ciTypeArrayKlass* array_klass = pop_typeArray();
1361      // Put assert here for right type?
1362      push_long();
1363      break;
1364    }
1365  case Bytecodes::_lastore:
1366    {
1367      pop_long();
1368      pop_int();
1369      pop_typeArray();
1370      // assert here?
1371      break;
1372    }
1373  case Bytecodes::_lcmp:
1374    {
1375      pop_long();
1376      pop_long();
1377      push_int();
1378      break;
1379    }
1380  case Bytecodes::_lconst_0:
1381  case Bytecodes::_lconst_1:
1382    {
1383      push_long();
1384      break;
1385    }
1386  case Bytecodes::_ldc:
1387  case Bytecodes::_ldc_w:
1388  case Bytecodes::_ldc2_w:
1389    {
1390      do_ldc(str);
1391      break;
1392    }
1393
1394  case Bytecodes::_lload:   load_local_long(str->get_index());      break;
1395  case Bytecodes::_lload_0: load_local_long(0);                     break;
1396  case Bytecodes::_lload_1: load_local_long(1);                     break;
1397  case Bytecodes::_lload_2: load_local_long(2);                     break;
1398  case Bytecodes::_lload_3: load_local_long(3);                     break;
1399
1400  case Bytecodes::_lneg:
1401    {
1402      pop_long();
1403      push_long();
1404      break;
1405    }
1406  case Bytecodes::_lreturn:
1407    {
1408      pop_long();
1409      break;
1410    }
1411  case Bytecodes::_lshl:
1412  case Bytecodes::_lshr:
1413  case Bytecodes::_lushr:
1414    {
1415      pop_int();
1416      pop_long();
1417      push_long();
1418      break;
1419    }
1420  case Bytecodes::_lstore:   store_local_long(str->get_index());    break;
1421  case Bytecodes::_lstore_0: store_local_long(0);                   break;
1422  case Bytecodes::_lstore_1: store_local_long(1);                   break;
1423  case Bytecodes::_lstore_2: store_local_long(2);                   break;
1424  case Bytecodes::_lstore_3: store_local_long(3);                   break;
1425
1426  case Bytecodes::_multianewarray: do_multianewarray(str);          break;
1427
1428  case Bytecodes::_new:      do_new(str);                           break;
1429
1430  case Bytecodes::_newarray: do_newarray(str);                      break;
1431
1432  case Bytecodes::_pop:
1433    {
1434      pop();
1435      break;
1436    }
1437  case Bytecodes::_pop2:
1438    {
1439      pop();
1440      pop();
1441      break;
1442    }
1443
1444  case Bytecodes::_putfield:       do_putfield(str);                 break;
1445  case Bytecodes::_putstatic:      do_putstatic(str);                break;
1446
1447  case Bytecodes::_ret: do_ret(str);                                 break;
1448
1449  case Bytecodes::_swap:
1450    {
1451      ciType* value1 = pop_value();
1452      ciType* value2 = pop_value();
1453      push(value1);
1454      push(value2);
1455      break;
1456    }
1457  case Bytecodes::_wide:
1458  default:
1459    {
1460      // The iterator should skip this.
1461      ShouldNotReachHere();
1462      break;
1463    }
1464  }
1465
1466  if (CITraceTypeFlow) {
1467    print_on(tty);
1468  }
1469
1470  return (_trap_bci != -1);
1471}
1472
1473#ifndef PRODUCT
1474// ------------------------------------------------------------------
1475// ciTypeFlow::StateVector::print_cell_on
1476void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1477  ciType* type = type_at(c);
1478  if (type == top_type()) {
1479    st->print("top");
1480  } else if (type == bottom_type()) {
1481    st->print("bottom");
1482  } else if (type == null_type()) {
1483    st->print("null");
1484  } else if (type == long2_type()) {
1485    st->print("long2");
1486  } else if (type == double2_type()) {
1487    st->print("double2");
1488  } else if (is_int(type)) {
1489    st->print("int");
1490  } else if (is_long(type)) {
1491    st->print("long");
1492  } else if (is_float(type)) {
1493    st->print("float");
1494  } else if (is_double(type)) {
1495    st->print("double");
1496  } else if (type->is_return_address()) {
1497    st->print("address(%d)", type->as_return_address()->bci());
1498  } else {
1499    if (type->is_klass()) {
1500      type->as_klass()->name()->print_symbol_on(st);
1501    } else {
1502      st->print("UNEXPECTED TYPE");
1503      type->print();
1504    }
1505  }
1506}
1507
1508// ------------------------------------------------------------------
1509// ciTypeFlow::StateVector::print_on
1510void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1511  int num_locals   = _outer->max_locals();
1512  int num_stack    = stack_size();
1513  int num_monitors = monitor_count();
1514  st->print_cr("  State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1515  if (num_stack >= 0) {
1516    int i;
1517    for (i = 0; i < num_locals; i++) {
1518      st->print("    local %2d : ", i);
1519      print_cell_on(st, local(i));
1520      st->cr();
1521    }
1522    for (i = 0; i < num_stack; i++) {
1523      st->print("    stack %2d : ", i);
1524      print_cell_on(st, stack(i));
1525      st->cr();
1526    }
1527  }
1528}
1529#endif
1530
1531
1532// ------------------------------------------------------------------
1533// ciTypeFlow::SuccIter::next
1534//
1535void ciTypeFlow::SuccIter::next() {
1536  int succ_ct = _pred->successors()->length();
1537  int next = _index + 1;
1538  if (next < succ_ct) {
1539    _index = next;
1540    _succ = _pred->successors()->at(next);
1541    return;
1542  }
1543  for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1544    // Do not compile any code for unloaded exception types.
1545    // Following compiler passes are responsible for doing this also.
1546    ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1547    if (exception_klass->is_loaded()) {
1548      _index = next;
1549      _succ = _pred->exceptions()->at(i);
1550      return;
1551    }
1552    next++;
1553  }
1554  _index = -1;
1555  _succ = NULL;
1556}
1557
1558// ------------------------------------------------------------------
1559// ciTypeFlow::SuccIter::set_succ
1560//
1561void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1562  int succ_ct = _pred->successors()->length();
1563  if (_index < succ_ct) {
1564    _pred->successors()->at_put(_index, succ);
1565  } else {
1566    int idx = _index - succ_ct;
1567    _pred->exceptions()->at_put(idx, succ);
1568  }
1569}
1570
1571// ciTypeFlow::Block
1572//
1573// A basic block.
1574
1575// ------------------------------------------------------------------
1576// ciTypeFlow::Block::Block
1577ciTypeFlow::Block::Block(ciTypeFlow* outer,
1578                         ciBlock *ciblk,
1579                         ciTypeFlow::JsrSet* jsrs) {
1580  _ciblock = ciblk;
1581  _exceptions = NULL;
1582  _exc_klasses = NULL;
1583  _successors = NULL;
1584  _state = new (outer->arena()) StateVector(outer);
1585  JsrSet* new_jsrs =
1586    new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1587  jsrs->copy_into(new_jsrs);
1588  _jsrs = new_jsrs;
1589  _next = NULL;
1590  _on_work_list = false;
1591  _backedge_copy = false;
1592  _exception_entry = false;
1593  _trap_bci = -1;
1594  _trap_index = 0;
1595  df_init();
1596
1597  if (CITraceTypeFlow) {
1598    tty->print_cr(">> Created new block");
1599    print_on(tty);
1600  }
1601
1602  assert(this->outer() == outer, "outer link set up");
1603  assert(!outer->have_block_count(), "must not have mapped blocks yet");
1604}
1605
1606// ------------------------------------------------------------------
1607// ciTypeFlow::Block::df_init
1608void ciTypeFlow::Block::df_init() {
1609  _pre_order = -1; assert(!has_pre_order(), "");
1610  _post_order = -1; assert(!has_post_order(), "");
1611  _loop = NULL;
1612  _irreducible_entry = false;
1613  _rpo_next = NULL;
1614}
1615
1616// ------------------------------------------------------------------
1617// ciTypeFlow::Block::successors
1618//
1619// Get the successors for this Block.
1620GrowableArray<ciTypeFlow::Block*>*
1621ciTypeFlow::Block::successors(ciBytecodeStream* str,
1622                              ciTypeFlow::StateVector* state,
1623                              ciTypeFlow::JsrSet* jsrs) {
1624  if (_successors == NULL) {
1625    if (CITraceTypeFlow) {
1626      tty->print(">> Computing successors for block ");
1627      print_value_on(tty);
1628      tty->cr();
1629    }
1630
1631    ciTypeFlow* analyzer = outer();
1632    Arena* arena = analyzer->arena();
1633    Block* block = NULL;
1634    bool has_successor = !has_trap() &&
1635                         (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1636    if (!has_successor) {
1637      _successors =
1638        new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1639      // No successors
1640    } else if (control() == ciBlock::fall_through_bci) {
1641      assert(str->cur_bci() == limit(), "bad block end");
1642      // This block simply falls through to the next.
1643      _successors =
1644        new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1645
1646      Block* block = analyzer->block_at(limit(), _jsrs);
1647      assert(_successors->length() == FALL_THROUGH, "");
1648      _successors->append(block);
1649    } else {
1650      int current_bci = str->cur_bci();
1651      int next_bci = str->next_bci();
1652      int branch_bci = -1;
1653      Block* target = NULL;
1654      assert(str->next_bci() == limit(), "bad block end");
1655      // This block is not a simple fall-though.  Interpret
1656      // the current bytecode to find our successors.
1657      switch (str->cur_bc()) {
1658      case Bytecodes::_ifeq:         case Bytecodes::_ifne:
1659      case Bytecodes::_iflt:         case Bytecodes::_ifge:
1660      case Bytecodes::_ifgt:         case Bytecodes::_ifle:
1661      case Bytecodes::_if_icmpeq:    case Bytecodes::_if_icmpne:
1662      case Bytecodes::_if_icmplt:    case Bytecodes::_if_icmpge:
1663      case Bytecodes::_if_icmpgt:    case Bytecodes::_if_icmple:
1664      case Bytecodes::_if_acmpeq:    case Bytecodes::_if_acmpne:
1665      case Bytecodes::_ifnull:       case Bytecodes::_ifnonnull:
1666        // Our successors are the branch target and the next bci.
1667        branch_bci = str->get_dest();
1668        _successors =
1669          new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1670        assert(_successors->length() == IF_NOT_TAKEN, "");
1671        _successors->append(analyzer->block_at(next_bci, jsrs));
1672        assert(_successors->length() == IF_TAKEN, "");
1673        _successors->append(analyzer->block_at(branch_bci, jsrs));
1674        break;
1675
1676      case Bytecodes::_goto:
1677        branch_bci = str->get_dest();
1678        _successors =
1679          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1680        assert(_successors->length() == GOTO_TARGET, "");
1681        _successors->append(analyzer->block_at(branch_bci, jsrs));
1682        break;
1683
1684      case Bytecodes::_jsr:
1685        branch_bci = str->get_dest();
1686        _successors =
1687          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1688        assert(_successors->length() == GOTO_TARGET, "");
1689        _successors->append(analyzer->block_at(branch_bci, jsrs));
1690        break;
1691
1692      case Bytecodes::_goto_w:
1693      case Bytecodes::_jsr_w:
1694        _successors =
1695          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1696        assert(_successors->length() == GOTO_TARGET, "");
1697        _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1698        break;
1699
1700      case Bytecodes::_tableswitch:  {
1701        Bytecode_tableswitch *tableswitch =
1702          Bytecode_tableswitch_at(str->cur_bcp());
1703
1704        int len = tableswitch->length();
1705        _successors =
1706          new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1707        int bci = current_bci + tableswitch->default_offset();
1708        Block* block = analyzer->block_at(bci, jsrs);
1709        assert(_successors->length() == SWITCH_DEFAULT, "");
1710        _successors->append(block);
1711        while (--len >= 0) {
1712          int bci = current_bci + tableswitch->dest_offset_at(len);
1713          block = analyzer->block_at(bci, jsrs);
1714          assert(_successors->length() >= SWITCH_CASES, "");
1715          _successors->append_if_missing(block);
1716        }
1717        break;
1718      }
1719
1720      case Bytecodes::_lookupswitch: {
1721        Bytecode_lookupswitch *lookupswitch =
1722          Bytecode_lookupswitch_at(str->cur_bcp());
1723
1724        int npairs = lookupswitch->number_of_pairs();
1725        _successors =
1726          new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1727        int bci = current_bci + lookupswitch->default_offset();
1728        Block* block = analyzer->block_at(bci, jsrs);
1729        assert(_successors->length() == SWITCH_DEFAULT, "");
1730        _successors->append(block);
1731        while(--npairs >= 0) {
1732          LookupswitchPair *pair = lookupswitch->pair_at(npairs);
1733          int bci = current_bci + pair->offset();
1734          Block* block = analyzer->block_at(bci, jsrs);
1735          assert(_successors->length() >= SWITCH_CASES, "");
1736          _successors->append_if_missing(block);
1737        }
1738        break;
1739      }
1740
1741      case Bytecodes::_athrow:     case Bytecodes::_ireturn:
1742      case Bytecodes::_lreturn:    case Bytecodes::_freturn:
1743      case Bytecodes::_dreturn:    case Bytecodes::_areturn:
1744      case Bytecodes::_return:
1745        _successors =
1746          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1747        // No successors
1748        break;
1749
1750      case Bytecodes::_ret: {
1751        _successors =
1752          new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1753
1754        Cell local = state->local(str->get_index());
1755        ciType* return_address = state->type_at(local);
1756        assert(return_address->is_return_address(), "verify: wrong type");
1757        int bci = return_address->as_return_address()->bci();
1758        assert(_successors->length() == GOTO_TARGET, "");
1759        _successors->append(analyzer->block_at(bci, jsrs));
1760        break;
1761      }
1762
1763      case Bytecodes::_wide:
1764      default:
1765        ShouldNotReachHere();
1766        break;
1767      }
1768    }
1769  }
1770  return _successors;
1771}
1772
1773// ------------------------------------------------------------------
1774// ciTypeFlow::Block:compute_exceptions
1775//
1776// Compute the exceptional successors and types for this Block.
1777void ciTypeFlow::Block::compute_exceptions() {
1778  assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1779
1780  if (CITraceTypeFlow) {
1781    tty->print(">> Computing exceptions for block ");
1782    print_value_on(tty);
1783    tty->cr();
1784  }
1785
1786  ciTypeFlow* analyzer = outer();
1787  Arena* arena = analyzer->arena();
1788
1789  // Any bci in the block will do.
1790  ciExceptionHandlerStream str(analyzer->method(), start());
1791
1792  // Allocate our growable arrays.
1793  int exc_count = str.count();
1794  _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1795  _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1796                                                             0, NULL);
1797
1798  for ( ; !str.is_done(); str.next()) {
1799    ciExceptionHandler* handler = str.handler();
1800    int bci = handler->handler_bci();
1801    ciInstanceKlass* klass = NULL;
1802    if (bci == -1) {
1803      // There is no catch all.  It is possible to exit the method.
1804      break;
1805    }
1806    if (handler->is_catch_all()) {
1807      klass = analyzer->env()->Throwable_klass();
1808    } else {
1809      klass = handler->catch_klass();
1810    }
1811    _exceptions->append(analyzer->block_at(bci, _jsrs));
1812    _exc_klasses->append(klass);
1813  }
1814}
1815
1816// ------------------------------------------------------------------
1817// ciTypeFlow::Block::set_backedge_copy
1818// Use this only to make a pre-existing public block into a backedge copy.
1819void ciTypeFlow::Block::set_backedge_copy(bool z) {
1820  assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1821  _backedge_copy = z;
1822}
1823
1824// ------------------------------------------------------------------
1825// ciTypeFlow::Block::is_clonable_exit
1826//
1827// At most 2 normal successors, one of which continues looping,
1828// and all exceptional successors must exit.
1829bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1830  int normal_cnt  = 0;
1831  int in_loop_cnt = 0;
1832  for (SuccIter iter(this); !iter.done(); iter.next()) {
1833    Block* succ = iter.succ();
1834    if (iter.is_normal_ctrl()) {
1835      if (++normal_cnt > 2) return false;
1836      if (lp->contains(succ->loop())) {
1837        if (++in_loop_cnt > 1) return false;
1838      }
1839    } else {
1840      if (lp->contains(succ->loop())) return false;
1841    }
1842  }
1843  return in_loop_cnt == 1;
1844}
1845
1846// ------------------------------------------------------------------
1847// ciTypeFlow::Block::looping_succ
1848//
1849ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1850  assert(successors()->length() <= 2, "at most 2 normal successors");
1851  for (SuccIter iter(this); !iter.done(); iter.next()) {
1852    Block* succ = iter.succ();
1853    if (lp->contains(succ->loop())) {
1854      return succ;
1855    }
1856  }
1857  return NULL;
1858}
1859
1860#ifndef PRODUCT
1861// ------------------------------------------------------------------
1862// ciTypeFlow::Block::print_value_on
1863void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1864  if (has_pre_order()) st->print("#%-2d ", pre_order());
1865  if (has_rpo())       st->print("rpo#%-2d ", rpo());
1866  st->print("[%d - %d)", start(), limit());
1867  if (is_loop_head()) st->print(" lphd");
1868  if (is_irreducible_entry()) st->print(" irred");
1869  if (_jsrs->size() > 0) { st->print("/");  _jsrs->print_on(st); }
1870  if (is_backedge_copy())  st->print("/backedge_copy");
1871}
1872
1873// ------------------------------------------------------------------
1874// ciTypeFlow::Block::print_on
1875void ciTypeFlow::Block::print_on(outputStream* st) const {
1876  if ((Verbose || WizardMode)) {
1877    outer()->method()->print_codes_on(start(), limit(), st);
1878  }
1879  st->print_cr("  ====================================================  ");
1880  st->print ("  ");
1881  print_value_on(st);
1882  st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1883  if (loop() && loop()->parent() != NULL) {
1884    st->print(" loops:");
1885    Loop* lp = loop();
1886    do {
1887      st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
1888      if (lp->is_irreducible()) st->print("(ir)");
1889      lp = lp->parent();
1890    } while (lp->parent() != NULL);
1891  }
1892  st->cr();
1893  _state->print_on(st);
1894  if (_successors == NULL) {
1895    st->print_cr("  No successor information");
1896  } else {
1897    int num_successors = _successors->length();
1898    st->print_cr("  Successors : %d", num_successors);
1899    for (int i = 0; i < num_successors; i++) {
1900      Block* successor = _successors->at(i);
1901      st->print("    ");
1902      successor->print_value_on(st);
1903      st->cr();
1904    }
1905  }
1906  if (_exceptions == NULL) {
1907    st->print_cr("  No exception information");
1908  } else {
1909    int num_exceptions = _exceptions->length();
1910    st->print_cr("  Exceptions : %d", num_exceptions);
1911    for (int i = 0; i < num_exceptions; i++) {
1912      Block* exc_succ = _exceptions->at(i);
1913      ciInstanceKlass* exc_klass = _exc_klasses->at(i);
1914      st->print("    ");
1915      exc_succ->print_value_on(st);
1916      st->print(" -- ");
1917      exc_klass->name()->print_symbol_on(st);
1918      st->cr();
1919    }
1920  }
1921  if (has_trap()) {
1922    st->print_cr("  Traps on %d with trap index %d", trap_bci(), trap_index());
1923  }
1924  st->print_cr("  ====================================================  ");
1925}
1926#endif
1927
1928#ifndef PRODUCT
1929// ------------------------------------------------------------------
1930// ciTypeFlow::LocalSet::print_on
1931void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
1932  st->print("{");
1933  for (int i = 0; i < max; i++) {
1934    if (test(i)) st->print(" %d", i);
1935  }
1936  if (limit > max) {
1937    st->print(" %d..%d ", max, limit);
1938  }
1939  st->print(" }");
1940}
1941#endif
1942
1943// ciTypeFlow
1944//
1945// This is a pass over the bytecodes which computes the following:
1946//   basic block structure
1947//   interpreter type-states (a la the verifier)
1948
1949// ------------------------------------------------------------------
1950// ciTypeFlow::ciTypeFlow
1951ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
1952  _env = env;
1953  _method = method;
1954  _methodBlocks = method->get_method_blocks();
1955  _max_locals = method->max_locals();
1956  _max_stack = method->max_stack();
1957  _code_size = method->code_size();
1958  _has_irreducible_entry = false;
1959  _osr_bci = osr_bci;
1960  _failure_reason = NULL;
1961  assert(0 <= start_bci() && start_bci() < code_size() , err_msg("correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size()));
1962  _work_list = NULL;
1963
1964  _ciblock_count = _methodBlocks->num_blocks();
1965  _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
1966  for (int i = 0; i < _ciblock_count; i++) {
1967    _idx_to_blocklist[i] = NULL;
1968  }
1969  _block_map = NULL;  // until all blocks are seen
1970  _jsr_count = 0;
1971  _jsr_records = NULL;
1972}
1973
1974// ------------------------------------------------------------------
1975// ciTypeFlow::work_list_next
1976//
1977// Get the next basic block from our work list.
1978ciTypeFlow::Block* ciTypeFlow::work_list_next() {
1979  assert(!work_list_empty(), "work list must not be empty");
1980  Block* next_block = _work_list;
1981  _work_list = next_block->next();
1982  next_block->set_next(NULL);
1983  next_block->set_on_work_list(false);
1984  return next_block;
1985}
1986
1987// ------------------------------------------------------------------
1988// ciTypeFlow::add_to_work_list
1989//
1990// Add a basic block to our work list.
1991// List is sorted by decreasing postorder sort (same as increasing RPO)
1992void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
1993  assert(!block->is_on_work_list(), "must not already be on work list");
1994
1995  if (CITraceTypeFlow) {
1996    tty->print(">> Adding block ");
1997    block->print_value_on(tty);
1998    tty->print_cr(" to the work list : ");
1999  }
2000
2001  block->set_on_work_list(true);
2002
2003  // decreasing post order sort
2004
2005  Block* prev = NULL;
2006  Block* current = _work_list;
2007  int po = block->post_order();
2008  while (current != NULL) {
2009    if (!current->has_post_order() || po > current->post_order())
2010      break;
2011    prev = current;
2012    current = current->next();
2013  }
2014  if (prev == NULL) {
2015    block->set_next(_work_list);
2016    _work_list = block;
2017  } else {
2018    block->set_next(current);
2019    prev->set_next(block);
2020  }
2021
2022  if (CITraceTypeFlow) {
2023    tty->cr();
2024  }
2025}
2026
2027// ------------------------------------------------------------------
2028// ciTypeFlow::block_at
2029//
2030// Return the block beginning at bci which has a JsrSet compatible
2031// with jsrs.
2032ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2033  // First find the right ciBlock.
2034  if (CITraceTypeFlow) {
2035    tty->print(">> Requesting block for %d/", bci);
2036    jsrs->print_on(tty);
2037    tty->cr();
2038  }
2039
2040  ciBlock* ciblk = _methodBlocks->block_containing(bci);
2041  assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2042  Block* block = get_block_for(ciblk->index(), jsrs, option);
2043
2044  assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2045
2046  if (CITraceTypeFlow) {
2047    if (block != NULL) {
2048      tty->print(">> Found block ");
2049      block->print_value_on(tty);
2050      tty->cr();
2051    } else {
2052      tty->print_cr(">> No such block.");
2053    }
2054  }
2055
2056  return block;
2057}
2058
2059// ------------------------------------------------------------------
2060// ciTypeFlow::make_jsr_record
2061//
2062// Make a JsrRecord for a given (entry, return) pair, if such a record
2063// does not already exist.
2064ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2065                                                   int return_address) {
2066  if (_jsr_records == NULL) {
2067    _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2068                                                           _jsr_count,
2069                                                           0,
2070                                                           NULL);
2071  }
2072  JsrRecord* record = NULL;
2073  int len = _jsr_records->length();
2074  for (int i = 0; i < len; i++) {
2075    JsrRecord* record = _jsr_records->at(i);
2076    if (record->entry_address() == entry_address &&
2077        record->return_address() == return_address) {
2078      return record;
2079    }
2080  }
2081
2082  record = new (arena()) JsrRecord(entry_address, return_address);
2083  _jsr_records->append(record);
2084  return record;
2085}
2086
2087// ------------------------------------------------------------------
2088// ciTypeFlow::flow_exceptions
2089//
2090// Merge the current state into all exceptional successors at the
2091// current point in the code.
2092void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2093                                 GrowableArray<ciInstanceKlass*>* exc_klasses,
2094                                 ciTypeFlow::StateVector* state) {
2095  int len = exceptions->length();
2096  assert(exc_klasses->length() == len, "must have same length");
2097  for (int i = 0; i < len; i++) {
2098    Block* block = exceptions->at(i);
2099    ciInstanceKlass* exception_klass = exc_klasses->at(i);
2100
2101    if (!exception_klass->is_loaded()) {
2102      // Do not compile any code for unloaded exception types.
2103      // Following compiler passes are responsible for doing this also.
2104      continue;
2105    }
2106
2107    if (block->meet_exception(exception_klass, state)) {
2108      // Block was modified and has PO.  Add it to the work list.
2109      if (block->has_post_order() &&
2110          !block->is_on_work_list()) {
2111        add_to_work_list(block);
2112      }
2113    }
2114  }
2115}
2116
2117// ------------------------------------------------------------------
2118// ciTypeFlow::flow_successors
2119//
2120// Merge the current state into all successors at the current point
2121// in the code.
2122void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2123                                 ciTypeFlow::StateVector* state) {
2124  int len = successors->length();
2125  for (int i = 0; i < len; i++) {
2126    Block* block = successors->at(i);
2127    if (block->meet(state)) {
2128      // Block was modified and has PO.  Add it to the work list.
2129      if (block->has_post_order() &&
2130          !block->is_on_work_list()) {
2131        add_to_work_list(block);
2132      }
2133    }
2134  }
2135}
2136
2137// ------------------------------------------------------------------
2138// ciTypeFlow::can_trap
2139//
2140// Tells if a given instruction is able to generate an exception edge.
2141bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2142  // Cf. GenerateOopMap::do_exception_edge.
2143  if (!Bytecodes::can_trap(str.cur_bc()))  return false;
2144
2145  switch (str.cur_bc()) {
2146    // %%% FIXME: ldc of Class can generate an exception
2147    case Bytecodes::_ldc:
2148    case Bytecodes::_ldc_w:
2149    case Bytecodes::_ldc2_w:
2150    case Bytecodes::_aload_0:
2151      // These bytecodes can trap for rewriting.  We need to assume that
2152      // they do not throw exceptions to make the monitor analysis work.
2153      return false;
2154
2155    case Bytecodes::_ireturn:
2156    case Bytecodes::_lreturn:
2157    case Bytecodes::_freturn:
2158    case Bytecodes::_dreturn:
2159    case Bytecodes::_areturn:
2160    case Bytecodes::_return:
2161      // We can assume the monitor stack is empty in this analysis.
2162      return false;
2163
2164    case Bytecodes::_monitorexit:
2165      // We can assume monitors are matched in this analysis.
2166      return false;
2167  }
2168
2169  return true;
2170}
2171
2172// ------------------------------------------------------------------
2173// ciTypeFlow::clone_loop_heads
2174//
2175// Clone the loop heads
2176bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2177  bool rslt = false;
2178  for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2179    lp = iter.current();
2180    Block* head = lp->head();
2181    if (lp == loop_tree_root() ||
2182        lp->is_irreducible() ||
2183        !head->is_clonable_exit(lp))
2184      continue;
2185
2186    // check not already cloned
2187    if (head->backedge_copy_count() != 0)
2188      continue;
2189
2190    // check _no_ shared head below us
2191    Loop* ch;
2192    for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2193    if (ch != NULL)
2194      continue;
2195
2196    // Clone head
2197    Block* new_head = head->looping_succ(lp);
2198    Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2199    // Update lp's info
2200    clone->set_loop(lp);
2201    lp->set_head(new_head);
2202    lp->set_tail(clone);
2203    // And move original head into outer loop
2204    head->set_loop(lp->parent());
2205
2206    rslt = true;
2207  }
2208  return rslt;
2209}
2210
2211// ------------------------------------------------------------------
2212// ciTypeFlow::clone_loop_head
2213//
2214// Clone lp's head and replace tail's successors with clone.
2215//
2216//  |
2217//  v
2218// head <-> body
2219//  |
2220//  v
2221// exit
2222//
2223// new_head
2224//
2225//  |
2226//  v
2227// head ----------\
2228//  |             |
2229//  |             v
2230//  |  clone <-> body
2231//  |    |
2232//  | /--/
2233//  | |
2234//  v v
2235// exit
2236//
2237ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2238  Block* head = lp->head();
2239  Block* tail = lp->tail();
2240  if (CITraceTypeFlow) {
2241    tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2242    tty->print("  for predecessor ");                tail->print_value_on(tty);
2243    tty->cr();
2244  }
2245  Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2246  assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2247
2248  assert(!clone->has_pre_order(), "just created");
2249  clone->set_next_pre_order();
2250
2251  // Insert clone after (orig) tail in reverse post order
2252  clone->set_rpo_next(tail->rpo_next());
2253  tail->set_rpo_next(clone);
2254
2255  // tail->head becomes tail->clone
2256  for (SuccIter iter(tail); !iter.done(); iter.next()) {
2257    if (iter.succ() == head) {
2258      iter.set_succ(clone);
2259    }
2260  }
2261  flow_block(tail, temp_vector, temp_set);
2262  if (head == tail) {
2263    // For self-loops, clone->head becomes clone->clone
2264    flow_block(clone, temp_vector, temp_set);
2265    for (SuccIter iter(clone); !iter.done(); iter.next()) {
2266      if (iter.succ() == head) {
2267        iter.set_succ(clone);
2268        break;
2269      }
2270    }
2271  }
2272  flow_block(clone, temp_vector, temp_set);
2273
2274  return clone;
2275}
2276
2277// ------------------------------------------------------------------
2278// ciTypeFlow::flow_block
2279//
2280// Interpret the effects of the bytecodes on the incoming state
2281// vector of a basic block.  Push the changed state to succeeding
2282// basic blocks.
2283void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2284                            ciTypeFlow::StateVector* state,
2285                            ciTypeFlow::JsrSet* jsrs) {
2286  if (CITraceTypeFlow) {
2287    tty->print("\n>> ANALYZING BLOCK : ");
2288    tty->cr();
2289    block->print_on(tty);
2290  }
2291  assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2292
2293  int start = block->start();
2294  int limit = block->limit();
2295  int control = block->control();
2296  if (control != ciBlock::fall_through_bci) {
2297    limit = control;
2298  }
2299
2300  // Grab the state from the current block.
2301  block->copy_state_into(state);
2302  state->def_locals()->clear();
2303
2304  GrowableArray<Block*>*           exceptions = block->exceptions();
2305  GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2306  bool has_exceptions = exceptions->length() > 0;
2307
2308  bool exceptions_used = false;
2309
2310  ciBytecodeStream str(method());
2311  str.reset_to_bci(start);
2312  Bytecodes::Code code;
2313  while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2314         str.cur_bci() < limit) {
2315    // Check for exceptional control flow from this point.
2316    if (has_exceptions && can_trap(str)) {
2317      flow_exceptions(exceptions, exc_klasses, state);
2318      exceptions_used = true;
2319    }
2320    // Apply the effects of the current bytecode to our state.
2321    bool res = state->apply_one_bytecode(&str);
2322
2323    // Watch for bailouts.
2324    if (failing())  return;
2325
2326    if (res) {
2327
2328      // We have encountered a trap.  Record it in this block.
2329      block->set_trap(state->trap_bci(), state->trap_index());
2330
2331      if (CITraceTypeFlow) {
2332        tty->print_cr(">> Found trap");
2333        block->print_on(tty);
2334      }
2335
2336      // Save set of locals defined in this block
2337      block->def_locals()->add(state->def_locals());
2338
2339      // Record (no) successors.
2340      block->successors(&str, state, jsrs);
2341
2342      assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2343
2344      // Discontinue interpretation of this Block.
2345      return;
2346    }
2347  }
2348
2349  GrowableArray<Block*>* successors = NULL;
2350  if (control != ciBlock::fall_through_bci) {
2351    // Check for exceptional control flow from this point.
2352    if (has_exceptions && can_trap(str)) {
2353      flow_exceptions(exceptions, exc_klasses, state);
2354      exceptions_used = true;
2355    }
2356
2357    // Fix the JsrSet to reflect effect of the bytecode.
2358    block->copy_jsrs_into(jsrs);
2359    jsrs->apply_control(this, &str, state);
2360
2361    // Find successor edges based on old state and new JsrSet.
2362    successors = block->successors(&str, state, jsrs);
2363
2364    // Apply the control changes to the state.
2365    state->apply_one_bytecode(&str);
2366  } else {
2367    // Fall through control
2368    successors = block->successors(&str, NULL, NULL);
2369  }
2370
2371  // Save set of locals defined in this block
2372  block->def_locals()->add(state->def_locals());
2373
2374  // Remove untaken exception paths
2375  if (!exceptions_used)
2376    exceptions->clear();
2377
2378  // Pass our state to successors.
2379  flow_successors(successors, state);
2380}
2381
2382// ------------------------------------------------------------------
2383// ciTypeFlow::PostOrderLoops::next
2384//
2385// Advance to next loop tree using a postorder, left-to-right traversal.
2386void ciTypeFlow::PostorderLoops::next() {
2387  assert(!done(), "must not be done.");
2388  if (_current->sibling() != NULL) {
2389    _current = _current->sibling();
2390    while (_current->child() != NULL) {
2391      _current = _current->child();
2392    }
2393  } else {
2394    _current = _current->parent();
2395  }
2396}
2397
2398// ------------------------------------------------------------------
2399// ciTypeFlow::PreOrderLoops::next
2400//
2401// Advance to next loop tree using a preorder, left-to-right traversal.
2402void ciTypeFlow::PreorderLoops::next() {
2403  assert(!done(), "must not be done.");
2404  if (_current->child() != NULL) {
2405    _current = _current->child();
2406  } else if (_current->sibling() != NULL) {
2407    _current = _current->sibling();
2408  } else {
2409    while (_current != _root && _current->sibling() == NULL) {
2410      _current = _current->parent();
2411    }
2412    if (_current == _root) {
2413      _current = NULL;
2414      assert(done(), "must be done.");
2415    } else {
2416      assert(_current->sibling() != NULL, "must be more to do");
2417      _current = _current->sibling();
2418    }
2419  }
2420}
2421
2422// ------------------------------------------------------------------
2423// ciTypeFlow::Loop::sorted_merge
2424//
2425// Merge the branch lp into this branch, sorting on the loop head
2426// pre_orders. Returns the leaf of the merged branch.
2427// Child and sibling pointers will be setup later.
2428// Sort is (looking from leaf towards the root)
2429//  descending on primary key: loop head's pre_order, and
2430//  ascending  on secondary key: loop tail's pre_order.
2431ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2432  Loop* leaf = this;
2433  Loop* prev = NULL;
2434  Loop* current = leaf;
2435  while (lp != NULL) {
2436    int lp_pre_order = lp->head()->pre_order();
2437    // Find insertion point for "lp"
2438    while (current != NULL) {
2439      if (current == lp)
2440        return leaf; // Already in list
2441      if (current->head()->pre_order() < lp_pre_order)
2442        break;
2443      if (current->head()->pre_order() == lp_pre_order &&
2444          current->tail()->pre_order() > lp->tail()->pre_order()) {
2445        break;
2446      }
2447      prev = current;
2448      current = current->parent();
2449    }
2450    Loop* next_lp = lp->parent(); // Save future list of items to insert
2451    // Insert lp before current
2452    lp->set_parent(current);
2453    if (prev != NULL) {
2454      prev->set_parent(lp);
2455    } else {
2456      leaf = lp;
2457    }
2458    prev = lp;     // Inserted item is new prev[ious]
2459    lp = next_lp;  // Next item to insert
2460  }
2461  return leaf;
2462}
2463
2464// ------------------------------------------------------------------
2465// ciTypeFlow::build_loop_tree
2466//
2467// Incrementally build loop tree.
2468void ciTypeFlow::build_loop_tree(Block* blk) {
2469  assert(!blk->is_post_visited(), "precondition");
2470  Loop* innermost = NULL; // merge of loop tree branches over all successors
2471
2472  for (SuccIter iter(blk); !iter.done(); iter.next()) {
2473    Loop*  lp   = NULL;
2474    Block* succ = iter.succ();
2475    if (!succ->is_post_visited()) {
2476      // Found backedge since predecessor post visited, but successor is not
2477      assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2478
2479      // Create a LoopNode to mark this loop.
2480      lp = new (arena()) Loop(succ, blk);
2481      if (succ->loop() == NULL)
2482        succ->set_loop(lp);
2483      // succ->loop will be updated to innermost loop on a later call, when blk==succ
2484
2485    } else {  // Nested loop
2486      lp = succ->loop();
2487
2488      // If succ is loop head, find outer loop.
2489      while (lp != NULL && lp->head() == succ) {
2490        lp = lp->parent();
2491      }
2492      if (lp == NULL) {
2493        // Infinite loop, it's parent is the root
2494        lp = loop_tree_root();
2495      }
2496    }
2497
2498    // Check for irreducible loop.
2499    // Successor has already been visited. If the successor's loop head
2500    // has already been post-visited, then this is another entry into the loop.
2501    while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2502      _has_irreducible_entry = true;
2503      lp->set_irreducible(succ);
2504      if (!succ->is_on_work_list()) {
2505        // Assume irreducible entries need more data flow
2506        add_to_work_list(succ);
2507      }
2508      Loop* plp = lp->parent();
2509      if (plp == NULL) {
2510        // This only happens for some irreducible cases.  The parent
2511        // will be updated during a later pass.
2512        break;
2513      }
2514      lp = plp;
2515    }
2516
2517    // Merge loop tree branch for all successors.
2518    innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2519
2520  } // end loop
2521
2522  if (innermost == NULL) {
2523    assert(blk->successors()->length() == 0, "CFG exit");
2524    blk->set_loop(loop_tree_root());
2525  } else if (innermost->head() == blk) {
2526    // If loop header, complete the tree pointers
2527    if (blk->loop() != innermost) {
2528#if ASSERT
2529      assert(blk->loop()->head() == innermost->head(), "same head");
2530      Loop* dl;
2531      for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2532      assert(dl == blk->loop(), "blk->loop() already in innermost list");
2533#endif
2534      blk->set_loop(innermost);
2535    }
2536    innermost->def_locals()->add(blk->def_locals());
2537    Loop* l = innermost;
2538    Loop* p = l->parent();
2539    while (p && l->head() == blk) {
2540      l->set_sibling(p->child());  // Put self on parents 'next child'
2541      p->set_child(l);             // Make self the first child of parent
2542      p->def_locals()->add(l->def_locals());
2543      l = p;                       // Walk up the parent chain
2544      p = l->parent();
2545    }
2546  } else {
2547    blk->set_loop(innermost);
2548    innermost->def_locals()->add(blk->def_locals());
2549  }
2550}
2551
2552// ------------------------------------------------------------------
2553// ciTypeFlow::Loop::contains
2554//
2555// Returns true if lp is nested loop.
2556bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2557  assert(lp != NULL, "");
2558  if (this == lp || head() == lp->head()) return true;
2559  int depth1 = depth();
2560  int depth2 = lp->depth();
2561  if (depth1 > depth2)
2562    return false;
2563  while (depth1 < depth2) {
2564    depth2--;
2565    lp = lp->parent();
2566  }
2567  return this == lp;
2568}
2569
2570// ------------------------------------------------------------------
2571// ciTypeFlow::Loop::depth
2572//
2573// Loop depth
2574int ciTypeFlow::Loop::depth() const {
2575  int dp = 0;
2576  for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2577    dp++;
2578  return dp;
2579}
2580
2581#ifndef PRODUCT
2582// ------------------------------------------------------------------
2583// ciTypeFlow::Loop::print
2584void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2585  for (int i = 0; i < indent; i++) st->print(" ");
2586  st->print("%d<-%d %s",
2587            is_root() ? 0 : this->head()->pre_order(),
2588            is_root() ? 0 : this->tail()->pre_order(),
2589            is_irreducible()?" irr":"");
2590  st->print(" defs: ");
2591  def_locals()->print_on(st, _head->outer()->method()->max_locals());
2592  st->cr();
2593  for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2594    ch->print(st, indent+2);
2595}
2596#endif
2597
2598// ------------------------------------------------------------------
2599// ciTypeFlow::df_flow_types
2600//
2601// Perform the depth first type flow analysis. Helper for flow_types.
2602void ciTypeFlow::df_flow_types(Block* start,
2603                               bool do_flow,
2604                               StateVector* temp_vector,
2605                               JsrSet* temp_set) {
2606  int dft_len = 100;
2607  GrowableArray<Block*> stk(dft_len);
2608
2609  ciBlock* dummy = _methodBlocks->make_dummy_block();
2610  JsrSet* root_set = new JsrSet(NULL, 0);
2611  Block* root_head = new (arena()) Block(this, dummy, root_set);
2612  Block* root_tail = new (arena()) Block(this, dummy, root_set);
2613  root_head->set_pre_order(0);
2614  root_head->set_post_order(0);
2615  root_tail->set_pre_order(max_jint);
2616  root_tail->set_post_order(max_jint);
2617  set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2618
2619  stk.push(start);
2620
2621  _next_pre_order = 0;  // initialize pre_order counter
2622  _rpo_list = NULL;
2623  int next_po = 0;      // initialize post_order counter
2624
2625  // Compute RPO and the control flow graph
2626  int size;
2627  while ((size = stk.length()) > 0) {
2628    Block* blk = stk.top(); // Leave node on stack
2629    if (!blk->is_visited()) {
2630      // forward arc in graph
2631      assert (!blk->has_pre_order(), "");
2632      blk->set_next_pre_order();
2633
2634      if (_next_pre_order >= MaxNodeLimit / 2) {
2635        // Too many basic blocks.  Bail out.
2636        // This can happen when try/finally constructs are nested to depth N,
2637        // and there is O(2**N) cloning of jsr bodies.  See bug 4697245!
2638        // "MaxNodeLimit / 2" is used because probably the parser will
2639        // generate at least twice that many nodes and bail out.
2640        record_failure("too many basic blocks");
2641        return;
2642      }
2643      if (do_flow) {
2644        flow_block(blk, temp_vector, temp_set);
2645        if (failing()) return; // Watch for bailouts.
2646      }
2647    } else if (!blk->is_post_visited()) {
2648      // cross or back arc
2649      for (SuccIter iter(blk); !iter.done(); iter.next()) {
2650        Block* succ = iter.succ();
2651        if (!succ->is_visited()) {
2652          stk.push(succ);
2653        }
2654      }
2655      if (stk.length() == size) {
2656        // There were no additional children, post visit node now
2657        stk.pop(); // Remove node from stack
2658
2659        build_loop_tree(blk);
2660        blk->set_post_order(next_po++);   // Assign post order
2661        prepend_to_rpo_list(blk);
2662        assert(blk->is_post_visited(), "");
2663
2664        if (blk->is_loop_head() && !blk->is_on_work_list()) {
2665          // Assume loop heads need more data flow
2666          add_to_work_list(blk);
2667        }
2668      }
2669    } else {
2670      stk.pop(); // Remove post-visited node from stack
2671    }
2672  }
2673}
2674
2675// ------------------------------------------------------------------
2676// ciTypeFlow::flow_types
2677//
2678// Perform the type flow analysis, creating and cloning Blocks as
2679// necessary.
2680void ciTypeFlow::flow_types() {
2681  ResourceMark rm;
2682  StateVector* temp_vector = new StateVector(this);
2683  JsrSet* temp_set = new JsrSet(NULL, 16);
2684
2685  // Create the method entry block.
2686  Block* start = block_at(start_bci(), temp_set);
2687
2688  // Load the initial state into it.
2689  const StateVector* start_state = get_start_state();
2690  if (failing())  return;
2691  start->meet(start_state);
2692
2693  // Depth first visit
2694  df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2695
2696  if (failing())  return;
2697  assert(_rpo_list == start, "must be start");
2698
2699  // Any loops found?
2700  if (loop_tree_root()->child() != NULL &&
2701      env()->comp_level() >= CompLevel_full_optimization) {
2702      // Loop optimizations are not performed on Tier1 compiles.
2703
2704    bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2705
2706    // If some loop heads were cloned, recompute postorder and loop tree
2707    if (changed) {
2708      loop_tree_root()->set_child(NULL);
2709      for (Block* blk = _rpo_list; blk != NULL;) {
2710        Block* next = blk->rpo_next();
2711        blk->df_init();
2712        blk = next;
2713      }
2714      df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2715    }
2716  }
2717
2718  if (CITraceTypeFlow) {
2719    tty->print_cr("\nLoop tree");
2720    loop_tree_root()->print();
2721  }
2722
2723  // Continue flow analysis until fixed point reached
2724
2725  debug_only(int max_block = _next_pre_order;)
2726
2727  while (!work_list_empty()) {
2728    Block* blk = work_list_next();
2729    assert (blk->has_post_order(), "post order assigned above");
2730
2731    flow_block(blk, temp_vector, temp_set);
2732
2733    assert (max_block == _next_pre_order, "no new blocks");
2734    assert (!failing(), "no more bailouts");
2735  }
2736}
2737
2738// ------------------------------------------------------------------
2739// ciTypeFlow::map_blocks
2740//
2741// Create the block map, which indexes blocks in reverse post-order.
2742void ciTypeFlow::map_blocks() {
2743  assert(_block_map == NULL, "single initialization");
2744  int block_ct = _next_pre_order;
2745  _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2746  assert(block_ct == block_count(), "");
2747
2748  Block* blk = _rpo_list;
2749  for (int m = 0; m < block_ct; m++) {
2750    int rpo = blk->rpo();
2751    assert(rpo == m, "should be sequential");
2752    _block_map[rpo] = blk;
2753    blk = blk->rpo_next();
2754  }
2755  assert(blk == NULL, "should be done");
2756
2757  for (int j = 0; j < block_ct; j++) {
2758    assert(_block_map[j] != NULL, "must not drop any blocks");
2759    Block* block = _block_map[j];
2760    // Remove dead blocks from successor lists:
2761    for (int e = 0; e <= 1; e++) {
2762      GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2763      for (int k = 0; k < l->length(); k++) {
2764        Block* s = l->at(k);
2765        if (!s->has_post_order()) {
2766          if (CITraceTypeFlow) {
2767            tty->print("Removing dead %s successor of #%d: ", (e? "exceptional":  "normal"), block->pre_order());
2768            s->print_value_on(tty);
2769            tty->cr();
2770          }
2771          l->remove(s);
2772          --k;
2773        }
2774      }
2775    }
2776  }
2777}
2778
2779// ------------------------------------------------------------------
2780// ciTypeFlow::get_block_for
2781//
2782// Find a block with this ciBlock which has a compatible JsrSet.
2783// If no such block exists, create it, unless the option is no_create.
2784// If the option is create_backedge_copy, always create a fresh backedge copy.
2785ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2786  Arena* a = arena();
2787  GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2788  if (blocks == NULL) {
2789    // Query only?
2790    if (option == no_create)  return NULL;
2791
2792    // Allocate the growable array.
2793    blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2794    _idx_to_blocklist[ciBlockIndex] = blocks;
2795  }
2796
2797  if (option != create_backedge_copy) {
2798    int len = blocks->length();
2799    for (int i = 0; i < len; i++) {
2800      Block* block = blocks->at(i);
2801      if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2802        return block;
2803      }
2804    }
2805  }
2806
2807  // Query only?
2808  if (option == no_create)  return NULL;
2809
2810  // We did not find a compatible block.  Create one.
2811  Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2812  if (option == create_backedge_copy)  new_block->set_backedge_copy(true);
2813  blocks->append(new_block);
2814  return new_block;
2815}
2816
2817// ------------------------------------------------------------------
2818// ciTypeFlow::backedge_copy_count
2819//
2820int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2821  GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2822
2823  if (blocks == NULL) {
2824    return 0;
2825  }
2826
2827  int count = 0;
2828  int len = blocks->length();
2829  for (int i = 0; i < len; i++) {
2830    Block* block = blocks->at(i);
2831    if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2832      count++;
2833    }
2834  }
2835
2836  return count;
2837}
2838
2839// ------------------------------------------------------------------
2840// ciTypeFlow::do_flow
2841//
2842// Perform type inference flow analysis.
2843void ciTypeFlow::do_flow() {
2844  if (CITraceTypeFlow) {
2845    tty->print_cr("\nPerforming flow analysis on method");
2846    method()->print();
2847    if (is_osr_flow())  tty->print(" at OSR bci %d", start_bci());
2848    tty->cr();
2849    method()->print_codes();
2850  }
2851  if (CITraceTypeFlow) {
2852    tty->print_cr("Initial CI Blocks");
2853    print_on(tty);
2854  }
2855  flow_types();
2856  // Watch for bailouts.
2857  if (failing()) {
2858    return;
2859  }
2860
2861  map_blocks();
2862
2863  if (CIPrintTypeFlow || CITraceTypeFlow) {
2864    rpo_print_on(tty);
2865  }
2866}
2867
2868// ------------------------------------------------------------------
2869// ciTypeFlow::record_failure()
2870// The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
2871// This is required because there is not a 1-1 relation between the ciEnv and
2872// the TypeFlow passes within a compilation task.  For example, if the compiler
2873// is considering inlining a method, it will request a TypeFlow.  If that fails,
2874// the compilation as a whole may continue without the inlining.  Some TypeFlow
2875// requests are not optional; if they fail the requestor is responsible for
2876// copying the failure reason up to the ciEnv.  (See Parse::Parse.)
2877void ciTypeFlow::record_failure(const char* reason) {
2878  if (env()->log() != NULL) {
2879    env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
2880  }
2881  if (_failure_reason == NULL) {
2882    // Record the first failure reason.
2883    _failure_reason = reason;
2884  }
2885}
2886
2887#ifndef PRODUCT
2888// ------------------------------------------------------------------
2889// ciTypeFlow::print_on
2890void ciTypeFlow::print_on(outputStream* st) const {
2891  // Walk through CI blocks
2892  st->print_cr("********************************************************");
2893  st->print   ("TypeFlow for ");
2894  method()->name()->print_symbol_on(st);
2895  int limit_bci = code_size();
2896  st->print_cr("  %d bytes", limit_bci);
2897  ciMethodBlocks  *mblks = _methodBlocks;
2898  ciBlock* current = NULL;
2899  for (int bci = 0; bci < limit_bci; bci++) {
2900    ciBlock* blk = mblks->block_containing(bci);
2901    if (blk != NULL && blk != current) {
2902      current = blk;
2903      current->print_on(st);
2904
2905      GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
2906      int num_blocks = (blocks == NULL) ? 0 : blocks->length();
2907
2908      if (num_blocks == 0) {
2909        st->print_cr("  No Blocks");
2910      } else {
2911        for (int i = 0; i < num_blocks; i++) {
2912          Block* block = blocks->at(i);
2913          block->print_on(st);
2914        }
2915      }
2916      st->print_cr("--------------------------------------------------------");
2917      st->cr();
2918    }
2919  }
2920  st->print_cr("********************************************************");
2921  st->cr();
2922}
2923
2924void ciTypeFlow::rpo_print_on(outputStream* st) const {
2925  st->print_cr("********************************************************");
2926  st->print   ("TypeFlow for ");
2927  method()->name()->print_symbol_on(st);
2928  int limit_bci = code_size();
2929  st->print_cr("  %d bytes", limit_bci);
2930  for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
2931    blk->print_on(st);
2932    st->print_cr("--------------------------------------------------------");
2933    st->cr();
2934  }
2935  st->print_cr("********************************************************");
2936  st->cr();
2937}
2938#endif
2939