1 /*
2 * Copyright 2000-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25
26 class ciTypeFlow : public ResourceObj {
27 private:
28 ciEnv* _env;
29 ciMethod* _method;
30 ciMethodBlocks* _methodBlocks;
31 int _osr_bci;
32
33 // information cached from the method:
34 int _max_locals;
35 int _max_stack;
36 int _code_size;
37 bool _has_irreducible_entry;
38
39 const char* _failure_reason;
40
41 public:
42 class StateVector;
43 class Loop;
44 class Block;
45
46 // Build a type flow analyzer
47 // Do an OSR analysis if osr_bci >= 0.
48 ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci = InvocationEntryBci);
49
50 // Accessors
51 ciMethod* method() const { return _method; }
52 ciEnv* env() { return _env; }
53 Arena* arena() { return _env->arena(); }
54 bool is_osr_flow() const{ return _osr_bci != InvocationEntryBci; }
55 int start_bci() const { return is_osr_flow()? _osr_bci: 0; }
56 int max_locals() const { return _max_locals; }
57 int max_stack() const { return _max_stack; }
58 int max_cells() const { return _max_locals + _max_stack; }
59 int code_size() const { return _code_size; }
60 bool has_irreducible_entry() const { return _has_irreducible_entry; }
61
62 // Represents information about an "active" jsr call. This
63 // class represents a call to the routine at some entry address
64 // with some distinct return address.
65 class JsrRecord : public ResourceObj {
66 private:
67 int _entry_address;
68 int _return_address;
69 public:
70 JsrRecord(int entry_address, int return_address) {
71 _entry_address = entry_address;
72 _return_address = return_address;
73 }
74
75 int entry_address() const { return _entry_address; }
76 int return_address() const { return _return_address; }
77
78 void print_on(outputStream* st) const {
79 #ifndef PRODUCT
80 st->print("%d->%d", entry_address(), return_address());
81 #endif
82 }
83 };
84
85 // A JsrSet represents some set of JsrRecords. This class
86 // is used to record a set of all jsr routines which we permit
87 // execution to return (ret) from.
88 //
89 // During abstract interpretation, JsrSets are used to determine
90 // whether two paths which reach a given block are unique, and
91 // should be cloned apart, or are compatible, and should merge
92 // together.
93 //
94 // Note that different amounts of effort can be expended determining
95 // if paths are compatible. <DISCUSSION>
96 class JsrSet : public ResourceObj {
97 private:
98 GrowableArray<JsrRecord*>* _set;
99
100 JsrRecord* record_at(int i) {
101 return _set->at(i);
102 }
103
104 // Insert the given JsrRecord into the JsrSet, maintaining the order
105 // of the set and replacing any element with the same entry address.
106 void insert_jsr_record(JsrRecord* record);
107
108 // Remove the JsrRecord with the given return address from the JsrSet.
109 void remove_jsr_record(int return_address);
110
111 public:
112 JsrSet(Arena* arena, int default_len = 4);
113
114 // Copy this JsrSet.
115 void copy_into(JsrSet* jsrs);
116
117 // Is this JsrSet compatible with some other JsrSet?
118 bool is_compatible_with(JsrSet* other);
119
120 // Apply the effect of a single bytecode to the JsrSet.
121 void apply_control(ciTypeFlow* analyzer,
122 ciBytecodeStream* str,
123 StateVector* state);
124
125 // Bring this JsrSet into agreement with this state by removing
126 // any JsrRecords that refer to addresses no longer mentioned in
127 // the state.
128 void apply_state(StateVector* state);
129
130 // What is the cardinality of this set?
131 int size() const { return _set->length(); }
132
133 void print_on(outputStream* st) const PRODUCT_RETURN;
134 };
135
136 class LocalSet VALUE_OBJ_CLASS_SPEC {
137 private:
138 enum Constants { max = 63 };
139 uint64_t _bits;
140 public:
141 LocalSet() : _bits(0) {}
142 void add(uint32_t i) { if (i < (uint32_t)max) _bits |= (1LL << i); }
143 void add(LocalSet* ls) { _bits |= ls->_bits; }
144 bool test(uint32_t i) const { return i < (uint32_t)max ? (_bits>>i)&1U : true; }
145 void clear() { _bits = 0; }
146 void print_on(outputStream* st, int limit) const PRODUCT_RETURN;
147 };
148
149 // Used as a combined index for locals and temps
150 enum Cell {
151 Cell_0, Cell_max = INT_MAX
152 };
153
154 // A StateVector summarizes the type information at some
155 // point in the program
156 class StateVector : public ResourceObj {
157 private:
158 ciType** _types;
159 int _stack_size;
160 int _monitor_count;
161 ciTypeFlow* _outer;
162
163 int _trap_bci;
164 int _trap_index;
165
166 LocalSet _def_locals; // For entire block
167
168 static ciType* type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer);
169
170 public:
171 // Special elements in our type lattice.
172 enum {
173 T_TOP = T_VOID, // why not?
174 T_BOTTOM = T_CONFLICT,
175 T_LONG2 = T_SHORT, // 2nd word of T_LONG
176 T_DOUBLE2 = T_CHAR, // 2nd word of T_DOUBLE
177 T_NULL = T_BYTE // for now.
178 };
179 static ciType* top_type() { return ciType::make((BasicType)T_TOP); }
180 static ciType* bottom_type() { return ciType::make((BasicType)T_BOTTOM); }
181 static ciType* long2_type() { return ciType::make((BasicType)T_LONG2); }
182 static ciType* double2_type(){ return ciType::make((BasicType)T_DOUBLE2); }
183 static ciType* null_type() { return ciType::make((BasicType)T_NULL); }
184
185 static ciType* half_type(ciType* t) {
186 switch (t->basic_type()) {
187 case T_LONG: return long2_type();
188 case T_DOUBLE: return double2_type();
189 default: ShouldNotReachHere(); return NULL;
190 }
191 }
192
193 // The meet operation for our type lattice.
194 ciType* type_meet(ciType* t1, ciType* t2) {
195 return type_meet_internal(t1, t2, outer());
196 }
197
198 // Accessors
199 ciTypeFlow* outer() const { return _outer; }
200
201 int stack_size() const { return _stack_size; }
202 void set_stack_size(int ss) { _stack_size = ss; }
203
204 int monitor_count() const { return _monitor_count; }
205 void set_monitor_count(int mc) { _monitor_count = mc; }
206
207 LocalSet* def_locals() { return &_def_locals; }
208 const LocalSet* def_locals() const { return &_def_locals; }
209
210 static Cell start_cell() { return (Cell)0; }
211 static Cell next_cell(Cell c) { return (Cell)(((int)c) + 1); }
212 Cell limit_cell() const {
213 return (Cell)(outer()->max_locals() + stack_size());
214 }
215
216 // Cell creation
217 Cell local(int lnum) const {
218 assert(lnum < outer()->max_locals(), "index check");
219 return (Cell)(lnum);
220 }
221
222 Cell stack(int snum) const {
223 assert(snum < stack_size(), "index check");
224 return (Cell)(outer()->max_locals() + snum);
225 }
226
227 Cell tos() const { return stack(stack_size()-1); }
228
229 // For external use only:
230 ciType* local_type_at(int i) const { return type_at(local(i)); }
231 ciType* stack_type_at(int i) const { return type_at(stack(i)); }
232
233 // Accessors for the type of some Cell c
234 ciType* type_at(Cell c) const {
235 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
236 return _types[c];
237 }
238
239 void set_type_at(Cell c, ciType* type) {
240 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
241 _types[c] = type;
242 }
243
244 // Top-of-stack operations.
245 void set_type_at_tos(ciType* type) { set_type_at(tos(), type); }
246 ciType* type_at_tos() const { return type_at(tos()); }
247
248 void push(ciType* type) {
249 _stack_size++;
250 set_type_at_tos(type);
251 }
252 void pop() {
253 debug_only(set_type_at_tos(bottom_type()));
254 _stack_size--;
255 }
256 ciType* pop_value() {
257 ciType* t = type_at_tos();
258 pop();
259 return t;
260 }
261
262 // Convenience operations.
263 bool is_reference(ciType* type) const {
264 return type == null_type() || !type->is_primitive_type();
265 }
266 bool is_int(ciType* type) const {
267 return type->basic_type() == T_INT;
268 }
269 bool is_long(ciType* type) const {
270 return type->basic_type() == T_LONG;
271 }
272 bool is_float(ciType* type) const {
273 return type->basic_type() == T_FLOAT;
274 }
275 bool is_double(ciType* type) const {
276 return type->basic_type() == T_DOUBLE;
277 }
278
279 void store_to_local(int lnum) {
280 _def_locals.add((uint) lnum);
281 }
282
283 void push_translate(ciType* type);
284
285 void push_int() {
286 push(ciType::make(T_INT));
287 }
288 void pop_int() {
289 assert(is_int(type_at_tos()), "must be integer");
290 pop();
291 }
292 void check_int(Cell c) {
293 assert(is_int(type_at(c)), "must be integer");
294 }
295 void push_double() {
296 push(ciType::make(T_DOUBLE));
297 push(double2_type());
298 }
299 void pop_double() {
300 assert(type_at_tos() == double2_type(), "must be 2nd half");
301 pop();
302 assert(is_double(type_at_tos()), "must be double");
303 pop();
304 }
305 void push_float() {
306 push(ciType::make(T_FLOAT));
307 }
308 void pop_float() {
309 assert(is_float(type_at_tos()), "must be float");
310 pop();
311 }
312 void push_long() {
313 push(ciType::make(T_LONG));
314 push(long2_type());
315 }
316 void pop_long() {
317 assert(type_at_tos() == long2_type(), "must be 2nd half");
318 pop();
319 assert(is_long(type_at_tos()), "must be long");
320 pop();
321 }
322 void push_object(ciKlass* klass) {
323 push(klass);
324 }
325 void pop_object() {
326 assert(is_reference(type_at_tos()), "must be reference type");
327 pop();
328 }
329 void pop_array() {
330 assert(type_at_tos() == null_type() ||
331 type_at_tos()->is_array_klass(), "must be array type");
332 pop();
333 }
334 // pop_objArray and pop_typeArray narrow the tos to ciObjArrayKlass
335 // or ciTypeArrayKlass (resp.). In the rare case that an explicit
336 // null is popped from the stack, we return NULL. Caller beware.
337 ciObjArrayKlass* pop_objArray() {
338 ciType* array = pop_value();
339 if (array == null_type()) return NULL;
340 assert(array->is_obj_array_klass(), "must be object array type");
341 return array->as_obj_array_klass();
342 }
343 ciTypeArrayKlass* pop_typeArray() {
344 ciType* array = pop_value();
345 if (array == null_type()) return NULL;
346 assert(array->is_type_array_klass(), "must be prim array type");
347 return array->as_type_array_klass();
348 }
349 void push_null() {
350 push(null_type());
351 }
352 void do_null_assert(ciKlass* unloaded_klass);
353
354 // Helper convenience routines.
355 void do_aaload(ciBytecodeStream* str);
356 void do_checkcast(ciBytecodeStream* str);
357 void do_getfield(ciBytecodeStream* str);
358 void do_getstatic(ciBytecodeStream* str);
359 void do_invoke(ciBytecodeStream* str, bool has_receiver);
360 void do_jsr(ciBytecodeStream* str);
361 void do_ldc(ciBytecodeStream* str);
362 void do_multianewarray(ciBytecodeStream* str);
363 void do_new(ciBytecodeStream* str);
364 void do_newarray(ciBytecodeStream* str);
365 void do_putfield(ciBytecodeStream* str);
366 void do_putstatic(ciBytecodeStream* str);
367 void do_ret(ciBytecodeStream* str);
368
369 void overwrite_local_double_long(int index) {
370 // Invalidate the previous local if it contains first half of
371 // a double or long value since it's seconf half is being overwritten.
372 int prev_index = index - 1;
373 if (prev_index >= 0 &&
374 (is_double(type_at(local(prev_index))) ||
375 is_long(type_at(local(prev_index))))) {
376 set_type_at(local(prev_index), bottom_type());
377 }
378 }
379
380 void load_local_object(int index) {
381 ciType* type = type_at(local(index));
382 assert(is_reference(type), "must be reference type");
383 push(type);
384 }
385 void store_local_object(int index) {
386 ciType* type = pop_value();
387 assert(is_reference(type) || type->is_return_address(),
388 "must be reference type or return address");
389 overwrite_local_double_long(index);
390 set_type_at(local(index), type);
391 store_to_local(index);
392 }
393
394 void load_local_double(int index) {
395 ciType* type = type_at(local(index));
396 ciType* type2 = type_at(local(index+1));
397 assert(is_double(type), "must be double type");
398 assert(type2 == double2_type(), "must be 2nd half");
399 push(type);
400 push(double2_type());
401 }
402 void store_local_double(int index) {
403 ciType* type2 = pop_value();
404 ciType* type = pop_value();
405 assert(is_double(type), "must be double");
406 assert(type2 == double2_type(), "must be 2nd half");
407 overwrite_local_double_long(index);
408 set_type_at(local(index), type);
409 set_type_at(local(index+1), type2);
410 store_to_local(index);
411 store_to_local(index+1);
412 }
413
414 void load_local_float(int index) {
415 ciType* type = type_at(local(index));
416 assert(is_float(type), "must be float type");
417 push(type);
418 }
419 void store_local_float(int index) {
420 ciType* type = pop_value();
421 assert(is_float(type), "must be float type");
422 overwrite_local_double_long(index);
423 set_type_at(local(index), type);
424 store_to_local(index);
425 }
426
427 void load_local_int(int index) {
428 ciType* type = type_at(local(index));
429 assert(is_int(type), "must be int type");
430 push(type);
431 }
432 void store_local_int(int index) {
433 ciType* type = pop_value();
434 assert(is_int(type), "must be int type");
435 overwrite_local_double_long(index);
436 set_type_at(local(index), type);
437 store_to_local(index);
438 }
439
440 void load_local_long(int index) {
441 ciType* type = type_at(local(index));
442 ciType* type2 = type_at(local(index+1));
443 assert(is_long(type), "must be long type");
444 assert(type2 == long2_type(), "must be 2nd half");
445 push(type);
446 push(long2_type());
447 }
448 void store_local_long(int index) {
449 ciType* type2 = pop_value();
450 ciType* type = pop_value();
451 assert(is_long(type), "must be long");
452 assert(type2 == long2_type(), "must be 2nd half");
453 overwrite_local_double_long(index);
454 set_type_at(local(index), type);
455 set_type_at(local(index+1), type2);
456 store_to_local(index);
457 store_to_local(index+1);
458 }
459
460 // Stop interpretation of this path with a trap.
461 void trap(ciBytecodeStream* str, ciKlass* klass, int index);
462
463 public:
464 StateVector(ciTypeFlow* outer);
465
466 // Copy our value into some other StateVector
467 void copy_into(StateVector* copy) const;
468
469 // Meets this StateVector with another, destructively modifying this
470 // one. Returns true if any modification takes place.
471 bool meet(const StateVector* incoming);
472
473 // Ditto, except that the incoming state is coming from an exception.
474 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming);
475
476 // Apply the effect of one bytecode to this StateVector
477 bool apply_one_bytecode(ciBytecodeStream* stream);
478
479 // What is the bci of the trap?
480 int trap_bci() { return _trap_bci; }
481
482 // What is the index associated with the trap?
483 int trap_index() { return _trap_index; }
484
485 void print_cell_on(outputStream* st, Cell c) const PRODUCT_RETURN;
486 void print_on(outputStream* st) const PRODUCT_RETURN;
487 };
488
489 // Parameter for "find_block" calls:
490 // Describes the difference between a public and backedge copy.
491 enum CreateOption {
492 create_public_copy,
493 create_backedge_copy,
494 no_create
495 };
496
497 // Successor iterator
498 class SuccIter : public StackObj {
499 private:
500 Block* _pred;
501 int _index;
502 Block* _succ;
503 public:
504 SuccIter() : _pred(NULL), _index(-1), _succ(NULL) {}
505 SuccIter(Block* pred) : _pred(pred), _index(-1), _succ(NULL) { next(); }
506 int index() { return _index; }
507 Block* pred() { return _pred; } // Return predecessor
508 bool done() { return _index < 0; } // Finished?
509 Block* succ() { return _succ; } // Return current successor
510 void next(); // Advance
511 void set_succ(Block* succ); // Update current successor
512 bool is_normal_ctrl() { return index() < _pred->successors()->length(); }
513 };
514
515 // A basic block
516 class Block : public ResourceObj {
517 private:
518 ciBlock* _ciblock;
519 GrowableArray<Block*>* _exceptions;
520 GrowableArray<ciInstanceKlass*>* _exc_klasses;
521 GrowableArray<Block*>* _successors;
522 StateVector* _state;
523 JsrSet* _jsrs;
524
525 int _trap_bci;
526 int _trap_index;
527
528 // pre_order, assigned at first visit. Used as block ID and "visited" tag
529 int _pre_order;
530
531 // A post-order, used to compute the reverse post order (RPO) provided to the client
532 int _post_order; // used to compute rpo
533
534 // Has this block been cloned for a loop backedge?
535 bool _backedge_copy;
536
537 // A pointer used for our internal work list
538 Block* _next;
539 bool _on_work_list; // on the work list
540 Block* _rpo_next; // Reverse post order list
541
542 // Loop info
543 Loop* _loop; // nearest loop
544 bool _irreducible_entry; // entry to irreducible loop
545 bool _exception_entry; // entry to exception handler
546
547 ciBlock* ciblock() const { return _ciblock; }
548 StateVector* state() const { return _state; }
549
550 // Compute the exceptional successors and types for this Block.
551 void compute_exceptions();
552
553 public:
554 // constructors
555 Block(ciTypeFlow* outer, ciBlock* ciblk, JsrSet* jsrs);
556
557 void set_trap(int trap_bci, int trap_index) {
558 _trap_bci = trap_bci;
559 _trap_index = trap_index;
560 assert(has_trap(), "");
561 }
562 bool has_trap() const { return _trap_bci != -1; }
563 int trap_bci() const { assert(has_trap(), ""); return _trap_bci; }
564 int trap_index() const { assert(has_trap(), ""); return _trap_index; }
565
566 // accessors
567 ciTypeFlow* outer() const { return state()->outer(); }
568 int start() const { return _ciblock->start_bci(); }
569 int limit() const { return _ciblock->limit_bci(); }
570 int control() const { return _ciblock->control_bci(); }
571 JsrSet* jsrs() const { return _jsrs; }
572
573 bool is_backedge_copy() const { return _backedge_copy; }
574 void set_backedge_copy(bool z);
575 int backedge_copy_count() const { return outer()->backedge_copy_count(ciblock()->index(), _jsrs); }
576
577 // access to entry state
578 int stack_size() const { return _state->stack_size(); }
579 int monitor_count() const { return _state->monitor_count(); }
580 ciType* local_type_at(int i) const { return _state->local_type_at(i); }
581 ciType* stack_type_at(int i) const { return _state->stack_type_at(i); }
582
583 // Data flow on locals
584 bool is_invariant_local(uint v) const {
585 assert(is_loop_head(), "only loop heads");
586 // Find outermost loop with same loop head
587 Loop* lp = loop();
588 while (lp->parent() != NULL) {
589 if (lp->parent()->head() != lp->head()) break;
590 lp = lp->parent();
591 }
592 return !lp->def_locals()->test(v);
593 }
594 LocalSet* def_locals() { return _state->def_locals(); }
595 const LocalSet* def_locals() const { return _state->def_locals(); }
596
597 // Get the successors for this Block.
598 GrowableArray<Block*>* successors(ciBytecodeStream* str,
599 StateVector* state,
600 JsrSet* jsrs);
601 GrowableArray<Block*>* successors() {
602 assert(_successors != NULL, "must be filled in");
603 return _successors;
604 }
605
606 // Get the exceptional successors for this Block.
607 GrowableArray<Block*>* exceptions() {
608 if (_exceptions == NULL) {
609 compute_exceptions();
610 }
611 return _exceptions;
612 }
613
614 // Get the exception klasses corresponding to the
615 // exceptional successors for this Block.
616 GrowableArray<ciInstanceKlass*>* exc_klasses() {
617 if (_exc_klasses == NULL) {
618 compute_exceptions();
619 }
620 return _exc_klasses;
621 }
622
623 // Is this Block compatible with a given JsrSet?
624 bool is_compatible_with(JsrSet* other) {
625 return _jsrs->is_compatible_with(other);
626 }
627
628 // Copy the value of our state vector into another.
629 void copy_state_into(StateVector* copy) const {
630 _state->copy_into(copy);
631 }
632
633 // Copy the value of our JsrSet into another
634 void copy_jsrs_into(JsrSet* copy) const {
635 _jsrs->copy_into(copy);
636 }
637
638 // Remove dead address from the state and also from the JsrSet.
639 // The reduces useless cloning for complex jsr/ret constructs.
640 bool delete_dead_addresses();
641
642 // Meets the start state of this block with another state, destructively
643 // modifying this one. Returns true if any modification takes place.
644 bool meet(const StateVector* incoming) {
645 return state()->meet(incoming);
646 }
647
648 // Ditto, except that the incoming state is coming from an
649 // exception path. This means the stack is replaced by the
650 // appropriate exception type.
651 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming) {
652 return state()->meet_exception(exc, incoming);
653 }
654
655 // Work list manipulation
656 void set_next(Block* block) { _next = block; }
657 Block* next() const { return _next; }
658
659 void set_on_work_list(bool c) { _on_work_list = c; }
660 bool is_on_work_list() const { return _on_work_list; }
661
662 bool has_pre_order() const { return _pre_order >= 0; }
663 void set_pre_order(int po) { assert(!has_pre_order(), ""); _pre_order = po; }
664 int pre_order() const { assert(has_pre_order(), ""); return _pre_order; }
665 void set_next_pre_order() { set_pre_order(outer()->inc_next_pre_order()); }
666 bool is_start() const { return _pre_order == outer()->start_block_num(); }
667
668 // Reverse post order
669 void df_init();
670 bool has_post_order() const { return _post_order >= 0; }
671 void set_post_order(int po) { assert(!has_post_order() && po >= 0, ""); _post_order = po; }
672 void reset_post_order(int o){ _post_order = o; }
673 int post_order() const { assert(has_post_order(), ""); return _post_order; }
674
675 bool has_rpo() const { return has_post_order() && outer()->have_block_count(); }
676 int rpo() const { assert(has_rpo(), ""); return outer()->block_count() - post_order() - 1; }
677 void set_rpo_next(Block* b) { _rpo_next = b; }
678 Block* rpo_next() { return _rpo_next; }
679
680 // Loops
681 Loop* loop() const { return _loop; }
682 void set_loop(Loop* lp) { _loop = lp; }
683 bool is_loop_head() const { return _loop && _loop->head() == this; }
684 void set_irreducible_entry(bool c) { _irreducible_entry = c; }
685 bool is_irreducible_entry() const { return _irreducible_entry; }
686 bool is_visited() const { return has_pre_order(); }
687 bool is_post_visited() const { return has_post_order(); }
688 bool is_clonable_exit(Loop* lp);
689 Block* looping_succ(Loop* lp); // Successor inside of loop
690 bool is_single_entry_loop_head() const {
691 if (!is_loop_head()) return false;
692 for (Loop* lp = loop(); lp != NULL && lp->head() == this; lp = lp->parent())
693 if (lp->is_irreducible()) return false;
694 return true;
695 }
696
697 void print_value_on(outputStream* st) const PRODUCT_RETURN;
698 void print_on(outputStream* st) const PRODUCT_RETURN;
699 };
700
701 // Loop
702 class Loop : public ResourceObj {
703 private:
704 Loop* _parent;
705 Loop* _sibling; // List of siblings, null terminated
706 Loop* _child; // Head of child list threaded thru sibling pointer
707 Block* _head; // Head of loop
708 Block* _tail; // Tail of loop
709 bool _irreducible;
710 LocalSet _def_locals;
711
712 public:
713 Loop(Block* head, Block* tail) :
714 _head(head), _tail(tail),
715 _parent(NULL), _sibling(NULL), _child(NULL),
716 _irreducible(false), _def_locals() {}
717
718 Loop* parent() const { return _parent; }
719 Loop* sibling() const { return _sibling; }
720 Loop* child() const { return _child; }
721 Block* head() const { return _head; }
722 Block* tail() const { return _tail; }
723 void set_parent(Loop* p) { _parent = p; }
724 void set_sibling(Loop* s) { _sibling = s; }
725 void set_child(Loop* c) { _child = c; }
726 void set_head(Block* hd) { _head = hd; }
727 void set_tail(Block* tl) { _tail = tl; }
728
729 int depth() const; // nesting depth
730
731 // Returns true if lp is a nested loop or us.
732 bool contains(Loop* lp) const;
733 bool contains(Block* blk) const { return contains(blk->loop()); }
734
735 // Data flow on locals
736 LocalSet* def_locals() { return &_def_locals; }
737 const LocalSet* def_locals() const { return &_def_locals; }
738
739 // Merge the branch lp into this branch, sorting on the loop head
740 // pre_orders. Returns the new branch.
741 Loop* sorted_merge(Loop* lp);
742
743 // Mark non-single entry to loop
744 void set_irreducible(Block* entry) {
745 _irreducible = true;
746 entry->set_irreducible_entry(true);
747 }
748 bool is_irreducible() const { return _irreducible; }
749
750 bool is_root() const { return _tail->pre_order() == max_jint; }
751
752 void print(outputStream* st = tty, int indent = 0) const PRODUCT_RETURN;
753 };
754
755 // Postorder iteration over the loop tree.
756 class PostorderLoops : public StackObj {
757 private:
758 Loop* _root;
759 Loop* _current;
760 public:
761 PostorderLoops(Loop* root) : _root(root), _current(root) {
762 while (_current->child() != NULL) {
763 _current = _current->child();
764 }
765 }
766 bool done() { return _current == NULL; } // Finished iterating?
767 void next(); // Advance to next loop
768 Loop* current() { return _current; } // Return current loop.
769 };
770
771 // Preorder iteration over the loop tree.
772 class PreorderLoops : public StackObj {
773 private:
774 Loop* _root;
775 Loop* _current;
776 public:
777 PreorderLoops(Loop* root) : _root(root), _current(root) {}
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 // Standard indexes of successors, for various bytecodes.
784 enum {
785 FALL_THROUGH = 0, // normal control
786 IF_NOT_TAKEN = 0, // the not-taken branch of an if (i.e., fall-through)
787 IF_TAKEN = 1, // the taken branch of an if
788 GOTO_TARGET = 0, // unique successor for goto, jsr, or ret
789 SWITCH_DEFAULT = 0, // default branch of a switch
790 SWITCH_CASES = 1 // first index for any non-default switch branches
791 // Unlike in other blocks, the successors of a switch are listed uniquely.
792 };
793
794 private:
795 // A mapping from pre_order to Blocks. This array is created
796 // only at the end of the flow.
797 Block** _block_map;
798
799 // For each ciBlock index, a list of Blocks which share this ciBlock.
800 GrowableArray<Block*>** _idx_to_blocklist;
801 // count of ciBlocks
802 int _ciblock_count;
803
804 // Tells if a given instruction is able to generate an exception edge.
805 bool can_trap(ciBytecodeStream& str);
806
807 // Clone the loop heads. Returns true if any cloning occurred.
808 bool clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
809
810 // Clone lp's head and replace tail's successors with clone.
811 Block* clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
812
813 public:
814 // Return the block beginning at bci which has a JsrSet compatible
815 // with jsrs.
816 Block* block_at(int bci, JsrSet* set, CreateOption option = create_public_copy);
817
818 // block factory
819 Block* get_block_for(int ciBlockIndex, JsrSet* jsrs, CreateOption option = create_public_copy);
820
821 // How many of the blocks have the backedge_copy bit set?
822 int backedge_copy_count(int ciBlockIndex, JsrSet* jsrs) const;
823
824 // Return an existing block containing bci which has a JsrSet compatible
825 // with jsrs, or NULL if there is none.
826 Block* existing_block_at(int bci, JsrSet* set) { return block_at(bci, set, no_create); }
827
828 // Tell whether the flow analysis has encountered an error of some sort.
829 bool failing() { return env()->failing() || _failure_reason != NULL; }
830
831 // Reason this compilation is failing, such as "too many basic blocks".
832 const char* failure_reason() { return _failure_reason; }
833
834 // Note a failure.
835 void record_failure(const char* reason);
836
837 // Return the block of a given pre-order number.
838 int have_block_count() const { return _block_map != NULL; }
839 int block_count() const { assert(have_block_count(), "");
840 return _next_pre_order; }
841 Block* pre_order_at(int po) const { assert(0 <= po && po < block_count(), "out of bounds");
842 return _block_map[po]; }
843 Block* start_block() const { return pre_order_at(start_block_num()); }
844 int start_block_num() const { return 0; }
845 Block* rpo_at(int rpo) const { assert(0 <= rpo && rpo < block_count(), "out of bounds");
846 return _block_map[rpo]; }
847 int next_pre_order() { return _next_pre_order; }
848 int inc_next_pre_order() { return _next_pre_order++; }
849
850 private:
851 // A work list used during flow analysis.
852 Block* _work_list;
853
854 // List of blocks in reverse post order
855 Block* _rpo_list;
856
857 // Next Block::_pre_order. After mapping, doubles as block_count.
858 int _next_pre_order;
859
860 // Are there more blocks on the work list?
861 bool work_list_empty() { return _work_list == NULL; }
862
863 // Get the next basic block from our work list.
864 Block* work_list_next();
865
866 // Add a basic block to our work list.
867 void add_to_work_list(Block* block);
868
869 // Prepend a basic block to rpo list.
870 void prepend_to_rpo_list(Block* blk) {
871 blk->set_rpo_next(_rpo_list);
872 _rpo_list = blk;
873 }
874
875 // Root of the loop tree
876 Loop* _loop_tree_root;
877
878 // State used for make_jsr_record
879 int _jsr_count;
880 GrowableArray<JsrRecord*>* _jsr_records;
881
882 public:
883 // Make a JsrRecord for a given (entry, return) pair, if such a record
884 // does not already exist.
885 JsrRecord* make_jsr_record(int entry_address, int return_address);
886
887 void set_loop_tree_root(Loop* ltr) { _loop_tree_root = ltr; }
888 Loop* loop_tree_root() { return _loop_tree_root; }
889
890 private:
891 // Get the initial state for start_bci:
892 const StateVector* get_start_state();
893
894 // Merge the current state into all exceptional successors at the
895 // current point in the code.
896 void flow_exceptions(GrowableArray<Block*>* exceptions,
897 GrowableArray<ciInstanceKlass*>* exc_klasses,
898 StateVector* state);
899
900 // Merge the current state into all successors at the current point
901 // in the code.
902 void flow_successors(GrowableArray<Block*>* successors,
903 StateVector* state);
904
905 // Interpret the effects of the bytecodes on the incoming state
906 // vector of a basic block. Push the changed state to succeeding
907 // basic blocks.
908 void flow_block(Block* block,
909 StateVector* scratch_state,
910 JsrSet* scratch_jsrs);
911
912 // Perform the type flow analysis, creating and cloning Blocks as
913 // necessary.
914 void flow_types();
915
916 // Perform the depth first type flow analysis. Helper for flow_types.
917 void df_flow_types(Block* start,
918 bool do_flow,
919 StateVector* temp_vector,
920 JsrSet* temp_set);
921
922 // Incrementally build loop tree.
923 void build_loop_tree(Block* blk);
924
925 // Create the block map, which indexes blocks in pre_order.
926 void map_blocks();
927
928 public:
929 // Perform type inference flow analysis.
930 void do_flow();
931
932 void print_on(outputStream* st) const PRODUCT_RETURN;
933
934 void rpo_print_on(outputStream* st) const PRODUCT_RETURN;
935 };