1 /*
2 * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_CI_CITYPEFLOW_HPP
26 #define SHARE_VM_CI_CITYPEFLOW_HPP
27
28 #ifdef COMPILER2
29 #include "ci/ciEnv.hpp"
30 #include "ci/ciKlass.hpp"
31 #include "ci/ciMethodBlocks.hpp"
32 #endif
33
34
35 class ciTypeFlow : public ResourceObj {
36 private:
37 ciEnv* _env;
38 ciMethod* _method;
39 ciMethodBlocks* _methodBlocks;
40 int _osr_bci;
41
42 // information cached from the method:
43 int _max_locals;
44 int _max_stack;
45 int _code_size;
46 bool _has_irreducible_entry;
47
48 const char* _failure_reason;
49
50 public:
51 class StateVector;
52 class Loop;
53 class Block;
54
55 // Build a type flow analyzer
56 // Do an OSR analysis if osr_bci >= 0.
57 ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci = InvocationEntryBci);
58
59 // Accessors
60 ciMethod* method() const { return _method; }
61 ciEnv* env() { return _env; }
62 Arena* arena() { return _env->arena(); }
63 bool is_osr_flow() const{ return _osr_bci != InvocationEntryBci; }
64 int start_bci() const { return is_osr_flow()? _osr_bci: 0; }
65 int max_locals() const { return _max_locals; }
66 int max_stack() const { return _max_stack; }
67 int max_cells() const { return _max_locals + _max_stack; }
68 int code_size() const { return _code_size; }
69 bool has_irreducible_entry() const { return _has_irreducible_entry; }
70
71 // Represents information about an "active" jsr call. This
72 // class represents a call to the routine at some entry address
73 // with some distinct return address.
74 class JsrRecord : public ResourceObj {
75 private:
76 int _entry_address;
77 int _return_address;
78 public:
79 JsrRecord(int entry_address, int return_address) {
80 _entry_address = entry_address;
81 _return_address = return_address;
82 }
83
84 int entry_address() const { return _entry_address; }
85 int return_address() const { return _return_address; }
86
87 void print_on(outputStream* st) const {
88 #ifndef PRODUCT
89 st->print("%d->%d", entry_address(), return_address());
90 #endif
91 }
92 };
93
94 // A JsrSet represents some set of JsrRecords. This class
95 // is used to record a set of all jsr routines which we permit
96 // execution to return (ret) from.
97 //
98 // During abstract interpretation, JsrSets are used to determine
99 // whether two paths which reach a given block are unique, and
100 // should be cloned apart, or are compatible, and should merge
101 // together.
102 //
103 // Note that different amounts of effort can be expended determining
104 // if paths are compatible. <DISCUSSION>
105 class JsrSet : public ResourceObj {
106 private:
107 GrowableArray<JsrRecord*>* _set;
108
109 JsrRecord* record_at(int i) {
110 return _set->at(i);
111 }
112
113 // Insert the given JsrRecord into the JsrSet, maintaining the order
114 // of the set and replacing any element with the same entry address.
115 void insert_jsr_record(JsrRecord* record);
116
117 // Remove the JsrRecord with the given return address from the JsrSet.
118 void remove_jsr_record(int return_address);
119
120 public:
121 JsrSet(Arena* arena, int default_len = 4);
122
123 // Copy this JsrSet.
124 void copy_into(JsrSet* jsrs);
125
126 // Is this JsrSet compatible with some other JsrSet?
127 bool is_compatible_with(JsrSet* other);
128
129 // Apply the effect of a single bytecode to the JsrSet.
130 void apply_control(ciTypeFlow* analyzer,
131 ciBytecodeStream* str,
132 StateVector* state);
133
134 // What is the cardinality of this set?
135 int size() const { return _set->length(); }
136
137 void print_on(outputStream* st) const PRODUCT_RETURN;
138 };
139
140 class LocalSet VALUE_OBJ_CLASS_SPEC {
141 private:
142 enum Constants { max = 63 };
143 uint64_t _bits;
144 public:
145 LocalSet() : _bits(0) {}
146 void add(uint32_t i) { if (i < (uint32_t)max) _bits |= (1LL << i); }
147 void add(LocalSet* ls) { _bits |= ls->_bits; }
148 bool test(uint32_t i) const { return i < (uint32_t)max ? (_bits>>i)&1U : true; }
149 void clear() { _bits = 0; }
150 void print_on(outputStream* st, int limit) const PRODUCT_RETURN;
151 };
152
153 // Used as a combined index for locals and temps
154 enum Cell {
155 Cell_0, Cell_max = INT_MAX
156 };
157
158 // A StateVector summarizes the type information at some
159 // point in the program
160 class StateVector : public ResourceObj {
161 private:
162 ciType** _types;
163 int _stack_size;
164 int _monitor_count;
165 ciTypeFlow* _outer;
166
167 int _trap_bci;
168 int _trap_index;
169
170 LocalSet _def_locals; // For entire block
171
172 static ciType* type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer);
173
174 public:
175 // Special elements in our type lattice.
176 enum {
177 T_TOP = T_VOID, // why not?
178 T_BOTTOM = T_CONFLICT,
179 T_LONG2 = T_SHORT, // 2nd word of T_LONG
180 T_DOUBLE2 = T_CHAR, // 2nd word of T_DOUBLE
181 T_NULL = T_BYTE // for now.
182 };
183 static ciType* top_type() { return ciType::make((BasicType)T_TOP); }
184 static ciType* bottom_type() { return ciType::make((BasicType)T_BOTTOM); }
185 static ciType* long2_type() { return ciType::make((BasicType)T_LONG2); }
186 static ciType* double2_type(){ return ciType::make((BasicType)T_DOUBLE2); }
187 static ciType* null_type() { return ciType::make((BasicType)T_NULL); }
188
189 static ciType* half_type(ciType* t) {
190 switch (t->basic_type()) {
191 case T_LONG: return long2_type();
192 case T_DOUBLE: return double2_type();
193 default: ShouldNotReachHere(); return NULL;
194 }
195 }
196
197 // The meet operation for our type lattice.
198 ciType* type_meet(ciType* t1, ciType* t2) {
199 return type_meet_internal(t1, t2, outer());
200 }
201
202 // Accessors
203 ciTypeFlow* outer() const { return _outer; }
204
205 int stack_size() const { return _stack_size; }
206 void set_stack_size(int ss) { _stack_size = ss; }
207
208 int monitor_count() const { return _monitor_count; }
209 void set_monitor_count(int mc) { _monitor_count = mc; }
210
211 LocalSet* def_locals() { return &_def_locals; }
212 const LocalSet* def_locals() const { return &_def_locals; }
213
214 static Cell start_cell() { return (Cell)0; }
215 static Cell next_cell(Cell c) { return (Cell)(((int)c) + 1); }
216 Cell limit_cell() const {
217 return (Cell)(outer()->max_locals() + stack_size());
218 }
219
220 // Cell creation
221 Cell local(int lnum) const {
222 assert(lnum < outer()->max_locals(), "index check");
223 return (Cell)(lnum);
224 }
225
226 Cell stack(int snum) const {
227 assert(snum < stack_size(), "index check");
228 return (Cell)(outer()->max_locals() + snum);
229 }
230
231 Cell tos() const { return stack(stack_size()-1); }
232
233 // For external use only:
234 ciType* local_type_at(int i) const { return type_at(local(i)); }
235 ciType* stack_type_at(int i) const { return type_at(stack(i)); }
236
237 // Accessors for the type of some Cell c
238 ciType* type_at(Cell c) const {
239 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
240 return _types[c];
241 }
242
243 void set_type_at(Cell c, ciType* type) {
244 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
245 _types[c] = type;
246 }
247
248 // Top-of-stack operations.
249 void set_type_at_tos(ciType* type) { set_type_at(tos(), type); }
250 ciType* type_at_tos() const { return type_at(tos()); }
251
252 void push(ciType* type) {
253 _stack_size++;
254 set_type_at_tos(type);
255 }
256 void pop() {
257 debug_only(set_type_at_tos(bottom_type()));
258 _stack_size--;
259 }
260 ciType* pop_value() {
261 ciType* t = type_at_tos();
262 pop();
263 return t;
264 }
265
266 // Convenience operations.
267 bool is_reference(ciType* type) const {
268 return type == null_type() || !type->is_primitive_type();
269 }
270 bool is_int(ciType* type) const {
271 return type->basic_type() == T_INT;
272 }
273 bool is_long(ciType* type) const {
274 return type->basic_type() == T_LONG;
275 }
276 bool is_float(ciType* type) const {
277 return type->basic_type() == T_FLOAT;
278 }
279 bool is_double(ciType* type) const {
280 return type->basic_type() == T_DOUBLE;
281 }
282
283 void store_to_local(int lnum) {
284 _def_locals.add((uint) lnum);
285 }
286
287 void push_translate(ciType* type);
288
289 void push_int() {
290 push(ciType::make(T_INT));
291 }
292 void pop_int() {
293 assert(is_int(type_at_tos()), "must be integer");
294 pop();
295 }
296 void check_int(Cell c) {
297 assert(is_int(type_at(c)), "must be integer");
298 }
299 void push_double() {
300 push(ciType::make(T_DOUBLE));
301 push(double2_type());
302 }
303 void pop_double() {
304 assert(type_at_tos() == double2_type(), "must be 2nd half");
305 pop();
306 assert(is_double(type_at_tos()), "must be double");
307 pop();
308 }
309 void push_float() {
310 push(ciType::make(T_FLOAT));
311 }
312 void pop_float() {
313 assert(is_float(type_at_tos()), "must be float");
314 pop();
315 }
316 void push_long() {
317 push(ciType::make(T_LONG));
318 push(long2_type());
319 }
320 void pop_long() {
321 assert(type_at_tos() == long2_type(), "must be 2nd half");
322 pop();
323 assert(is_long(type_at_tos()), "must be long");
324 pop();
325 }
326 void push_object(ciKlass* klass) {
327 push(klass);
328 }
329 void pop_object() {
330 assert(is_reference(type_at_tos()), "must be reference type");
331 pop();
332 }
333 void pop_array() {
334 assert(type_at_tos() == null_type() ||
335 type_at_tos()->is_array_klass(), "must be array type");
336 pop();
337 }
338 // pop_objArray and pop_typeArray narrow the tos to ciObjArrayKlass
339 // or ciTypeArrayKlass (resp.). In the rare case that an explicit
340 // null is popped from the stack, we return NULL. Caller beware.
341 ciObjArrayKlass* pop_objArray() {
342 ciType* array = pop_value();
343 if (array == null_type()) return NULL;
344 assert(array->is_obj_array_klass(), "must be object array type");
345 return array->as_obj_array_klass();
346 }
347 ciTypeArrayKlass* pop_typeArray() {
348 ciType* array = pop_value();
349 if (array == null_type()) return NULL;
350 assert(array->is_type_array_klass(), "must be prim array type");
351 return array->as_type_array_klass();
352 }
353 void push_null() {
354 push(null_type());
355 }
356 void do_null_assert(ciKlass* unloaded_klass);
357
358 // Helper convenience routines.
359 void do_aaload(ciBytecodeStream* str);
360 void do_checkcast(ciBytecodeStream* str);
361 void do_getfield(ciBytecodeStream* str);
362 void do_getstatic(ciBytecodeStream* str);
363 void do_invoke(ciBytecodeStream* str, bool has_receiver);
364 void do_jsr(ciBytecodeStream* str);
365 void do_ldc(ciBytecodeStream* str);
366 void do_multianewarray(ciBytecodeStream* str);
367 void do_new(ciBytecodeStream* str);
368 void do_newarray(ciBytecodeStream* str);
369 void do_putfield(ciBytecodeStream* str);
370 void do_putstatic(ciBytecodeStream* str);
371 void do_ret(ciBytecodeStream* str);
372
373 void overwrite_local_double_long(int index) {
374 // Invalidate the previous local if it contains first half of
375 // a double or long value since it's seconf half is being overwritten.
376 int prev_index = index - 1;
377 if (prev_index >= 0 &&
378 (is_double(type_at(local(prev_index))) ||
379 is_long(type_at(local(prev_index))))) {
380 set_type_at(local(prev_index), bottom_type());
381 }
382 }
383
384 void load_local_object(int index) {
385 ciType* type = type_at(local(index));
386 assert(is_reference(type), "must be reference type");
387 push(type);
388 }
389 void store_local_object(int index) {
390 ciType* type = pop_value();
391 assert(is_reference(type) || type->is_return_address(),
392 "must be reference type or return address");
393 overwrite_local_double_long(index);
394 set_type_at(local(index), type);
395 store_to_local(index);
396 }
397
398 void load_local_double(int index) {
399 ciType* type = type_at(local(index));
400 ciType* type2 = type_at(local(index+1));
401 assert(is_double(type), "must be double type");
402 assert(type2 == double2_type(), "must be 2nd half");
403 push(type);
404 push(double2_type());
405 }
406 void store_local_double(int index) {
407 ciType* type2 = pop_value();
408 ciType* type = pop_value();
409 assert(is_double(type), "must be double");
410 assert(type2 == double2_type(), "must be 2nd half");
411 overwrite_local_double_long(index);
412 set_type_at(local(index), type);
413 set_type_at(local(index+1), type2);
414 store_to_local(index);
415 store_to_local(index+1);
416 }
417
418 void load_local_float(int index) {
419 ciType* type = type_at(local(index));
420 assert(is_float(type), "must be float type");
421 push(type);
422 }
423 void store_local_float(int index) {
424 ciType* type = pop_value();
425 assert(is_float(type), "must be float type");
426 overwrite_local_double_long(index);
427 set_type_at(local(index), type);
428 store_to_local(index);
429 }
430
431 void load_local_int(int index) {
432 ciType* type = type_at(local(index));
433 assert(is_int(type), "must be int type");
434 push(type);
435 }
436 void store_local_int(int index) {
437 ciType* type = pop_value();
438 assert(is_int(type), "must be int type");
439 overwrite_local_double_long(index);
440 set_type_at(local(index), type);
441 store_to_local(index);
442 }
443
444 void load_local_long(int index) {
445 ciType* type = type_at(local(index));
446 ciType* type2 = type_at(local(index+1));
447 assert(is_long(type), "must be long type");
448 assert(type2 == long2_type(), "must be 2nd half");
449 push(type);
450 push(long2_type());
451 }
452 void store_local_long(int index) {
453 ciType* type2 = pop_value();
454 ciType* type = pop_value();
455 assert(is_long(type), "must be long");
456 assert(type2 == long2_type(), "must be 2nd half");
457 overwrite_local_double_long(index);
458 set_type_at(local(index), type);
459 set_type_at(local(index+1), type2);
460 store_to_local(index);
461 store_to_local(index+1);
462 }
463
464 // Stop interpretation of this path with a trap.
465 void trap(ciBytecodeStream* str, ciKlass* klass, int index);
466
467 public:
468 StateVector(ciTypeFlow* outer);
469
470 // Copy our value into some other StateVector
471 void copy_into(StateVector* copy) const;
472
473 // Meets this StateVector with another, destructively modifying this
474 // one. Returns true if any modification takes place.
475 bool meet(const StateVector* incoming);
476
477 // Ditto, except that the incoming state is coming from an exception.
478 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming);
479
480 // Apply the effect of one bytecode to this StateVector
481 bool apply_one_bytecode(ciBytecodeStream* stream);
482
483 // What is the bci of the trap?
484 int trap_bci() { return _trap_bci; }
485
486 // What is the index associated with the trap?
487 int trap_index() { return _trap_index; }
488
489 void print_cell_on(outputStream* st, Cell c) const PRODUCT_RETURN;
490 void print_on(outputStream* st) const PRODUCT_RETURN;
491 };
492
493 // Parameter for "find_block" calls:
494 // Describes the difference between a public and backedge copy.
495 enum CreateOption {
496 create_public_copy,
497 create_backedge_copy,
498 no_create
499 };
500
501 // Successor iterator
502 class SuccIter : public StackObj {
503 private:
504 Block* _pred;
505 int _index;
506 Block* _succ;
507 public:
508 SuccIter() : _pred(NULL), _index(-1), _succ(NULL) {}
509 SuccIter(Block* pred) : _pred(pred), _index(-1), _succ(NULL) { next(); }
510 int index() { return _index; }
511 Block* pred() { return _pred; } // Return predecessor
512 bool done() { return _index < 0; } // Finished?
513 Block* succ() { return _succ; } // Return current successor
514 void next(); // Advance
515 void set_succ(Block* succ); // Update current successor
516 bool is_normal_ctrl() { return index() < _pred->successors()->length(); }
517 };
518
519 // A basic block
520 class Block : public ResourceObj {
521 private:
522 ciBlock* _ciblock;
523 GrowableArray<Block*>* _exceptions;
524 GrowableArray<ciInstanceKlass*>* _exc_klasses;
525 GrowableArray<Block*>* _successors;
526 GrowableArray<Block*>* _predecessors;
527 StateVector* _state;
528 JsrSet* _jsrs;
529
530 int _trap_bci;
531 int _trap_index;
532
533 // pre_order, assigned at first visit. Used as block ID and "visited" tag
534 int _pre_order;
535
536 // A post-order, used to compute the reverse post order (RPO) provided to the client
537 int _post_order; // used to compute rpo
538
539 // Has this block been cloned for a loop backedge?
540 bool _backedge_copy;
541
542 // This block is entry to irreducible loop.
543 bool _irreducible_entry;
544
545 // This block has monitor entry point.
546 bool _has_monitorenter;
547
548 // A pointer used for our internal work list
549 bool _on_work_list; // on the work list
550 Block* _next;
551 Block* _rpo_next; // Reverse post order list
552
553 // Loop info
554 Loop* _loop; // nearest loop
555
556 ciBlock* ciblock() const { return _ciblock; }
557 StateVector* state() const { return _state; }
558
559 // Compute the exceptional successors and types for this Block.
560 void compute_exceptions();
561
562 public:
563 // constructors
564 Block(ciTypeFlow* outer, ciBlock* ciblk, JsrSet* jsrs);
565
566 void set_trap(int trap_bci, int trap_index) {
567 _trap_bci = trap_bci;
568 _trap_index = trap_index;
569 assert(has_trap(), "");
570 }
571 bool has_trap() const { return _trap_bci != -1; }
572 int trap_bci() const { assert(has_trap(), ""); return _trap_bci; }
573 int trap_index() const { assert(has_trap(), ""); return _trap_index; }
574
575 // accessors
576 ciTypeFlow* outer() const { return state()->outer(); }
577 int start() const { return _ciblock->start_bci(); }
578 int limit() const { return _ciblock->limit_bci(); }
579 int control() const { return _ciblock->control_bci(); }
580 JsrSet* jsrs() const { return _jsrs; }
581
582 bool is_backedge_copy() const { return _backedge_copy; }
583 void set_backedge_copy(bool z);
584 int backedge_copy_count() const { return outer()->backedge_copy_count(ciblock()->index(), _jsrs); }
585
586 // access to entry state
587 int stack_size() const { return _state->stack_size(); }
588 int monitor_count() const { return _state->monitor_count(); }
589 ciType* local_type_at(int i) const { return _state->local_type_at(i); }
590 ciType* stack_type_at(int i) const { return _state->stack_type_at(i); }
591
592 // Data flow on locals
593 bool is_invariant_local(uint v) const {
594 assert(is_loop_head(), "only loop heads");
595 // Find outermost loop with same loop head
596 Loop* lp = loop();
597 while (lp->parent() != NULL) {
598 if (lp->parent()->head() != lp->head()) break;
599 lp = lp->parent();
600 }
601 return !lp->def_locals()->test(v);
602 }
603 LocalSet* def_locals() { return _state->def_locals(); }
604 const LocalSet* def_locals() const { return _state->def_locals(); }
605
606 // Get the successors for this Block.
607 GrowableArray<Block*>* successors(ciBytecodeStream* str,
608 StateVector* state,
609 JsrSet* jsrs);
610 GrowableArray<Block*>* successors() {
611 assert(_successors != NULL, "must be filled in");
612 return _successors;
613 }
614
615 // Predecessors of this block (including exception edges)
616 GrowableArray<Block*>* predecessors() {
617 assert(_predecessors != NULL, "must be filled in");
618 return _predecessors;
619 }
620
621 // Get the exceptional successors for this Block.
622 GrowableArray<Block*>* exceptions() {
623 if (_exceptions == NULL) {
624 compute_exceptions();
625 }
626 return _exceptions;
627 }
628
629 // Get the exception klasses corresponding to the
630 // exceptional successors for this Block.
631 GrowableArray<ciInstanceKlass*>* exc_klasses() {
632 if (_exc_klasses == NULL) {
633 compute_exceptions();
634 }
635 return _exc_klasses;
636 }
637
638 // Is this Block compatible with a given JsrSet?
639 bool is_compatible_with(JsrSet* other) {
640 return _jsrs->is_compatible_with(other);
641 }
642
643 // Copy the value of our state vector into another.
644 void copy_state_into(StateVector* copy) const {
645 _state->copy_into(copy);
646 }
647
648 // Copy the value of our JsrSet into another
649 void copy_jsrs_into(JsrSet* copy) const {
650 _jsrs->copy_into(copy);
651 }
652
653 // Meets the start state of this block with another state, destructively
654 // modifying this one. Returns true if any modification takes place.
655 bool meet(const StateVector* incoming) {
656 return state()->meet(incoming);
657 }
658
659 // Ditto, except that the incoming state is coming from an
660 // exception path. This means the stack is replaced by the
661 // appropriate exception type.
662 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming) {
663 return state()->meet_exception(exc, incoming);
664 }
665
666 // Work list manipulation
667 void set_next(Block* block) { _next = block; }
668 Block* next() const { return _next; }
669
670 void set_on_work_list(bool c) { _on_work_list = c; }
671 bool is_on_work_list() const { return _on_work_list; }
672
673 bool has_pre_order() const { return _pre_order >= 0; }
674 void set_pre_order(int po) { assert(!has_pre_order(), ""); _pre_order = po; }
675 int pre_order() const { assert(has_pre_order(), ""); return _pre_order; }
676 void set_next_pre_order() { set_pre_order(outer()->inc_next_pre_order()); }
677 bool is_start() const { return _pre_order == outer()->start_block_num(); }
678
679 // Reverse post order
680 void df_init();
681 bool has_post_order() const { return _post_order >= 0; }
682 void set_post_order(int po) { assert(!has_post_order() && po >= 0, ""); _post_order = po; }
683 void reset_post_order(int o){ _post_order = o; }
684 int post_order() const { assert(has_post_order(), ""); return _post_order; }
685
686 bool has_rpo() const { return has_post_order() && outer()->have_block_count(); }
687 int rpo() const { assert(has_rpo(), ""); return outer()->block_count() - post_order() - 1; }
688 void set_rpo_next(Block* b) { _rpo_next = b; }
689 Block* rpo_next() { return _rpo_next; }
690
691 // Loops
692 Loop* loop() const { return _loop; }
693 void set_loop(Loop* lp) { _loop = lp; }
694 bool is_loop_head() const { return _loop && _loop->head() == this; }
695 void set_irreducible_entry(bool c) { _irreducible_entry = c; }
696 bool is_irreducible_entry() const { return _irreducible_entry; }
697 void set_has_monitorenter() { _has_monitorenter = true; }
698 bool has_monitorenter() const { return _has_monitorenter; }
699 bool is_visited() const { return has_pre_order(); }
700 bool is_post_visited() const { return has_post_order(); }
701 bool is_clonable_exit(Loop* lp);
702 Block* looping_succ(Loop* lp); // Successor inside of loop
703 bool is_single_entry_loop_head() const {
704 if (!is_loop_head()) return false;
705 for (Loop* lp = loop(); lp != NULL && lp->head() == this; lp = lp->parent())
706 if (lp->is_irreducible()) return false;
707 return true;
708 }
709
710 void print_value_on(outputStream* st) const PRODUCT_RETURN;
711 void print_on(outputStream* st) const PRODUCT_RETURN;
712 };
713
714 // Loop
715 class Loop : public ResourceObj {
716 private:
717 Loop* _parent;
718 Loop* _sibling; // List of siblings, null terminated
719 Loop* _child; // Head of child list threaded thru sibling pointer
720 Block* _head; // Head of loop
721 Block* _tail; // Tail of loop
722 bool _irreducible;
723 LocalSet _def_locals;
724
725 public:
726 Loop(Block* head, Block* tail) :
727 _head(head), _tail(tail),
728 _parent(NULL), _sibling(NULL), _child(NULL),
729 _irreducible(false), _def_locals() {}
730
731 Loop* parent() const { return _parent; }
732 Loop* sibling() const { return _sibling; }
733 Loop* child() const { return _child; }
734 Block* head() const { return _head; }
735 Block* tail() const { return _tail; }
736 void set_parent(Loop* p) { _parent = p; }
737 void set_sibling(Loop* s) { _sibling = s; }
738 void set_child(Loop* c) { _child = c; }
739 void set_head(Block* hd) { _head = hd; }
740 void set_tail(Block* tl) { _tail = tl; }
741
742 int depth() const; // nesting depth
743
744 // Returns true if lp is a nested loop or us.
745 bool contains(Loop* lp) const;
746 bool contains(Block* blk) const { return contains(blk->loop()); }
747
748 // Data flow on locals
749 LocalSet* def_locals() { return &_def_locals; }
750 const LocalSet* def_locals() const { return &_def_locals; }
751
752 // Merge the branch lp into this branch, sorting on the loop head
753 // pre_orders. Returns the new branch.
754 Loop* sorted_merge(Loop* lp);
755
756 // Mark non-single entry to loop
757 void set_irreducible(Block* entry) {
758 _irreducible = true;
759 entry->set_irreducible_entry(true);
760 }
761 bool is_irreducible() const { return _irreducible; }
762
763 bool is_root() const { return _tail->pre_order() == max_jint; }
764
765 void print(outputStream* st = tty, int indent = 0) const PRODUCT_RETURN;
766 };
767
768 // Postorder iteration over the loop tree.
769 class PostorderLoops : public StackObj {
770 private:
771 Loop* _root;
772 Loop* _current;
773 public:
774 PostorderLoops(Loop* root) : _root(root), _current(root) {
775 while (_current->child() != NULL) {
776 _current = _current->child();
777 }
778 }
779 bool done() { return _current == NULL; } // Finished iterating?
780 void next(); // Advance to next loop
781 Loop* current() { return _current; } // Return current loop.
782 };
783
784 // Preorder iteration over the loop tree.
785 class PreorderLoops : public StackObj {
786 private:
787 Loop* _root;
788 Loop* _current;
789 public:
790 PreorderLoops(Loop* root) : _root(root), _current(root) {}
791 bool done() { return _current == NULL; } // Finished iterating?
792 void next(); // Advance to next loop
793 Loop* current() { return _current; } // Return current loop.
794 };
795
796 // Standard indexes of successors, for various bytecodes.
797 enum {
798 FALL_THROUGH = 0, // normal control
799 IF_NOT_TAKEN = 0, // the not-taken branch of an if (i.e., fall-through)
800 IF_TAKEN = 1, // the taken branch of an if
801 GOTO_TARGET = 0, // unique successor for goto, jsr, or ret
802 SWITCH_DEFAULT = 0, // default branch of a switch
803 SWITCH_CASES = 1 // first index for any non-default switch branches
804 // Unlike in other blocks, the successors of a switch are listed uniquely.
805 };
806
807 private:
808 // A mapping from pre_order to Blocks. This array is created
809 // only at the end of the flow.
810 Block** _block_map;
811
812 // For each ciBlock index, a list of Blocks which share this ciBlock.
813 GrowableArray<Block*>** _idx_to_blocklist;
814 // count of ciBlocks
815 int _ciblock_count;
816
817 // Tells if a given instruction is able to generate an exception edge.
818 bool can_trap(ciBytecodeStream& str);
819
820 // Clone the loop heads. Returns true if any cloning occurred.
821 bool clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
822
823 // Clone lp's head and replace tail's successors with clone.
824 Block* clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
825
826 public:
827 // Return the block beginning at bci which has a JsrSet compatible
828 // with jsrs.
829 Block* block_at(int bci, JsrSet* set, CreateOption option = create_public_copy);
830
831 // block factory
832 Block* get_block_for(int ciBlockIndex, JsrSet* jsrs, CreateOption option = create_public_copy);
833
834 // How many of the blocks have the backedge_copy bit set?
835 int backedge_copy_count(int ciBlockIndex, JsrSet* jsrs) const;
836
837 // Return an existing block containing bci which has a JsrSet compatible
838 // with jsrs, or NULL if there is none.
839 Block* existing_block_at(int bci, JsrSet* set) { return block_at(bci, set, no_create); }
840
841 // Tell whether the flow analysis has encountered an error of some sort.
842 bool failing() { return env()->failing() || _failure_reason != NULL; }
843
844 // Reason this compilation is failing, such as "too many basic blocks".
845 const char* failure_reason() { return _failure_reason; }
846
847 // Note a failure.
848 void record_failure(const char* reason);
849
850 // Return the block of a given pre-order number.
851 int have_block_count() const { return _block_map != NULL; }
852 int block_count() const { assert(have_block_count(), "");
853 return _next_pre_order; }
854 Block* pre_order_at(int po) const { assert(0 <= po && po < block_count(), "out of bounds");
855 return _block_map[po]; }
856 Block* start_block() const { return pre_order_at(start_block_num()); }
857 int start_block_num() const { return 0; }
858 Block* rpo_at(int rpo) const { assert(0 <= rpo && rpo < block_count(), "out of bounds");
859 return _block_map[rpo]; }
860 int next_pre_order() { return _next_pre_order; }
861 int inc_next_pre_order() { return _next_pre_order++; }
862
863 private:
864 // A work list used during flow analysis.
865 Block* _work_list;
866
867 // List of blocks in reverse post order
868 Block* _rpo_list;
869
870 // Next Block::_pre_order. After mapping, doubles as block_count.
871 int _next_pre_order;
872
873 // Are there more blocks on the work list?
874 bool work_list_empty() { return _work_list == NULL; }
875
876 // Get the next basic block from our work list.
877 Block* work_list_next();
878
879 // Add a basic block to our work list.
880 void add_to_work_list(Block* block);
881
882 // Prepend a basic block to rpo list.
883 void prepend_to_rpo_list(Block* blk) {
884 blk->set_rpo_next(_rpo_list);
885 _rpo_list = blk;
886 }
887
888 // Root of the loop tree
889 Loop* _loop_tree_root;
890
891 // State used for make_jsr_record
892 int _jsr_count;
893 GrowableArray<JsrRecord*>* _jsr_records;
894
895 public:
896 // Make a JsrRecord for a given (entry, return) pair, if such a record
897 // does not already exist.
898 JsrRecord* make_jsr_record(int entry_address, int return_address);
899
900 void set_loop_tree_root(Loop* ltr) { _loop_tree_root = ltr; }
901 Loop* loop_tree_root() { return _loop_tree_root; }
902
903 private:
904 // Get the initial state for start_bci:
905 const StateVector* get_start_state();
906
907 // Merge the current state into all exceptional successors at the
908 // current point in the code.
909 void flow_exceptions(GrowableArray<Block*>* exceptions,
910 GrowableArray<ciInstanceKlass*>* exc_klasses,
911 StateVector* state);
912
913 // Merge the current state into all successors at the current point
914 // in the code.
915 void flow_successors(GrowableArray<Block*>* successors,
916 StateVector* state);
917
918 // Interpret the effects of the bytecodes on the incoming state
919 // vector of a basic block. Push the changed state to succeeding
920 // basic blocks.
921 void flow_block(Block* block,
922 StateVector* scratch_state,
923 JsrSet* scratch_jsrs);
924
925 // Perform the type flow analysis, creating and cloning Blocks as
926 // necessary.
927 void flow_types();
928
929 // Perform the depth first type flow analysis. Helper for flow_types.
930 void df_flow_types(Block* start,
931 bool do_flow,
932 StateVector* temp_vector,
933 JsrSet* temp_set);
934
935 // Incrementally build loop tree.
936 void build_loop_tree(Block* blk);
937
938 // Create the block map, which indexes blocks in pre_order.
939 void map_blocks();
940
941 public:
942 // Perform type inference flow analysis.
943 void do_flow();
944
945 // Determine if bci is dominated by dom_bci
946 bool is_dominated_by(int bci, int dom_bci);
947
948 void print_on(outputStream* st) const PRODUCT_RETURN;
949
950 void rpo_print_on(outputStream* st) const PRODUCT_RETURN;
951 };
952
953 #endif // SHARE_VM_CI_CITYPEFLOW_HPP