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