1 /*
2 * Copyright 2000-2006 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
38 const char* _failure_reason;
39
40 public:
41 class StateVector;
42 class Block;
43
44 // Build a type flow analyzer
45 // Do an OSR analysis if osr_bci >= 0.
46 ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci = InvocationEntryBci);
47
48 // Accessors
49 ciMethod* method() const { return _method; }
50 ciEnv* env() { return _env; }
51 Arena* arena() { return _env->arena(); }
52 bool is_osr_flow() const{ return _osr_bci != InvocationEntryBci; }
53 int start_bci() const { return is_osr_flow()? _osr_bci: 0; }
54 int max_locals() const { return _max_locals; }
55 int max_stack() const { return _max_stack; }
56 int max_cells() const { return _max_locals + _max_stack; }
57 int code_size() const { return _code_size; }
58
59 // Represents information about an "active" jsr call. This
60 // class represents a call to the routine at some entry address
61 // with some distinct return address.
62 class JsrRecord : public ResourceObj {
63 private:
64 int _entry_address;
65 int _return_address;
66 public:
67 JsrRecord(int entry_address, int return_address) {
68 _entry_address = entry_address;
69 _return_address = return_address;
70 }
71
72 int entry_address() const { return _entry_address; }
73 int return_address() const { return _return_address; }
74
75 void print_on(outputStream* st) const {
76 #ifndef PRODUCT
77 st->print("%d->%d", entry_address(), return_address());
78 #endif
79 }
80 };
81
82 // A JsrSet represents some set of JsrRecords. This class
83 // is used to record a set of all jsr routines which we permit
84 // execution to return (ret) from.
85 //
86 // During abstract interpretation, JsrSets are used to determine
87 // whether two paths which reach a given block are unique, and
88 // should be cloned apart, or are compatible, and should merge
89 // together.
90 //
91 // Note that different amounts of effort can be expended determining
92 // if paths are compatible. <DISCUSSION>
93 class JsrSet : public ResourceObj {
94 private:
95 GrowableArray<JsrRecord*>* _set;
96
97 JsrRecord* record_at(int i) {
98 return _set->at(i);
99 }
100
101 // Insert the given JsrRecord into the JsrSet, maintaining the order
102 // of the set and replacing any element with the same entry address.
103 void insert_jsr_record(JsrRecord* record);
104
105 // Remove the JsrRecord with the given return address from the JsrSet.
106 void remove_jsr_record(int return_address);
107
108 public:
109 JsrSet(Arena* arena, int default_len = 4);
110
111 // Copy this JsrSet.
112 void copy_into(JsrSet* jsrs);
113
114 // Is this JsrSet compatible with some other JsrSet?
115 bool is_compatible_with(JsrSet* other);
116
117 // Apply the effect of a single bytecode to the JsrSet.
118 void apply_control(ciTypeFlow* analyzer,
119 ciBytecodeStream* str,
120 StateVector* state);
121
122 // What is the cardinality of this set?
123 int size() const { return _set->length(); }
124
125 void print_on(outputStream* st) const PRODUCT_RETURN;
126 };
127
128 // Used as a combined index for locals and temps
129 enum Cell {
130 Cell_0
131 };
132
133 // A StateVector summarizes the type information at some
134 // point in the program
135 class StateVector : public ResourceObj {
136 private:
137 ciType** _types;
138 int _stack_size;
139 int _monitor_count;
140 ciTypeFlow* _outer;
141
142 int _trap_bci;
143 int _trap_index;
144
145 static ciType* type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer);
146
147 public:
148 // Special elements in our type lattice.
149 enum {
150 T_TOP = T_VOID, // why not?
151 T_BOTTOM = T_CONFLICT,
152 T_LONG2 = T_SHORT, // 2nd word of T_LONG
153 T_DOUBLE2 = T_CHAR, // 2nd word of T_DOUBLE
154 T_NULL = T_BYTE // for now.
155 };
156 static ciType* top_type() { return ciType::make((BasicType)T_TOP); }
157 static ciType* bottom_type() { return ciType::make((BasicType)T_BOTTOM); }
158 static ciType* long2_type() { return ciType::make((BasicType)T_LONG2); }
159 static ciType* double2_type(){ return ciType::make((BasicType)T_DOUBLE2); }
160 static ciType* null_type() { return ciType::make((BasicType)T_NULL); }
161
162 static ciType* half_type(ciType* t) {
163 switch (t->basic_type()) {
164 case T_LONG: return long2_type();
165 case T_DOUBLE: return double2_type();
166 default: ShouldNotReachHere(); return NULL;
167 }
168 }
169
170 // The meet operation for our type lattice.
171 ciType* type_meet(ciType* t1, ciType* t2) {
172 return type_meet_internal(t1, t2, outer());
173 }
174
175 // Accessors
176 ciTypeFlow* outer() const { return _outer; }
177
178 int stack_size() const { return _stack_size; }
179 void set_stack_size(int ss) { _stack_size = ss; }
180
181 int monitor_count() const { return _monitor_count; }
182 void set_monitor_count(int mc) { _monitor_count = mc; }
183
184 static Cell start_cell() { return (Cell)0; }
185 static Cell next_cell(Cell c) { return (Cell)(((int)c) + 1); }
186 Cell limit_cell() const {
187 return (Cell)(outer()->max_locals() + stack_size());
188 }
189
190 // Cell creation
191 Cell local(int lnum) const {
192 assert(lnum < outer()->max_locals(), "index check");
193 return (Cell)(lnum);
194 }
195
196 Cell stack(int snum) const {
197 assert(snum < stack_size(), "index check");
198 return (Cell)(outer()->max_locals() + snum);
199 }
200
201 Cell tos() const { return stack(stack_size()-1); }
202
203 // For external use only:
204 ciType* local_type_at(int i) const { return type_at(local(i)); }
205 ciType* stack_type_at(int i) const { return type_at(stack(i)); }
206
207 // Accessors for the type of some Cell c
208 ciType* type_at(Cell c) const {
209 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
210 return _types[c];
211 }
212
213 void set_type_at(Cell c, ciType* type) {
214 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
215 _types[c] = type;
216 }
217
218 // Top-of-stack operations.
219 void set_type_at_tos(ciType* type) { set_type_at(tos(), type); }
220 ciType* type_at_tos() const { return type_at(tos()); }
221
222 void push(ciType* type) {
223 _stack_size++;
224 set_type_at_tos(type);
225 }
226 void pop() {
227 debug_only(set_type_at_tos(bottom_type()));
228 _stack_size--;
229 }
230 ciType* pop_value() {
231 ciType* t = type_at_tos();
232 pop();
233 return t;
234 }
235
236 // Convenience operations.
237 bool is_reference(ciType* type) const {
238 return type == null_type() || !type->is_primitive_type();
239 }
240 bool is_int(ciType* type) const {
241 return type->basic_type() == T_INT;
242 }
243 bool is_long(ciType* type) const {
244 return type->basic_type() == T_LONG;
245 }
246 bool is_float(ciType* type) const {
247 return type->basic_type() == T_FLOAT;
248 }
249 bool is_double(ciType* type) const {
250 return type->basic_type() == T_DOUBLE;
251 }
252
253 void push_translate(ciType* type);
254
255 void push_int() {
256 push(ciType::make(T_INT));
257 }
258 void pop_int() {
259 assert(is_int(type_at_tos()), "must be integer");
260 pop();
261 }
262 void check_int(Cell c) {
263 assert(is_int(type_at(c)), "must be integer");
264 }
265 void push_double() {
266 push(ciType::make(T_DOUBLE));
267 push(double2_type());
268 }
269 void pop_double() {
270 assert(type_at_tos() == double2_type(), "must be 2nd half");
271 pop();
272 assert(is_double(type_at_tos()), "must be double");
273 pop();
274 }
275 void push_float() {
276 push(ciType::make(T_FLOAT));
277 }
278 void pop_float() {
279 assert(is_float(type_at_tos()), "must be float");
280 pop();
281 }
282 void push_long() {
283 push(ciType::make(T_LONG));
284 push(long2_type());
285 }
286 void pop_long() {
287 assert(type_at_tos() == long2_type(), "must be 2nd half");
288 pop();
289 assert(is_long(type_at_tos()), "must be long");
290 pop();
291 }
292 void push_object(ciKlass* klass) {
293 push(klass);
294 }
295 void pop_object() {
296 assert(is_reference(type_at_tos()), "must be reference type");
297 pop();
298 }
299 void pop_array() {
300 assert(type_at_tos() == null_type() ||
301 type_at_tos()->is_array_klass(), "must be array type");
302 pop();
303 }
304 // pop_objArray and pop_typeArray narrow the tos to ciObjArrayKlass
305 // or ciTypeArrayKlass (resp.). In the rare case that an explicit
306 // null is popped from the stack, we return NULL. Caller beware.
307 ciObjArrayKlass* pop_objArray() {
308 ciType* array = pop_value();
309 if (array == null_type()) return NULL;
310 assert(array->is_obj_array_klass(), "must be object array type");
311 return array->as_obj_array_klass();
312 }
313 ciTypeArrayKlass* pop_typeArray() {
314 ciType* array = pop_value();
315 if (array == null_type()) return NULL;
316 assert(array->is_type_array_klass(), "must be prim array type");
317 return array->as_type_array_klass();
318 }
319 void push_null() {
320 push(null_type());
321 }
322 void do_null_assert(ciKlass* unloaded_klass);
323
324 // Helper convenience routines.
325 void do_aaload(ciBytecodeStream* str);
326 void do_checkcast(ciBytecodeStream* str);
327 void do_getfield(ciBytecodeStream* str);
328 void do_getstatic(ciBytecodeStream* str);
329 void do_invoke(ciBytecodeStream* str, bool has_receiver);
330 void do_jsr(ciBytecodeStream* str);
331 void do_ldc(ciBytecodeStream* str);
332 void do_multianewarray(ciBytecodeStream* str);
333 void do_new(ciBytecodeStream* str);
334 void do_newarray(ciBytecodeStream* str);
335 void do_putfield(ciBytecodeStream* str);
336 void do_putstatic(ciBytecodeStream* str);
337 void do_ret(ciBytecodeStream* str);
338
339 void overwrite_local_double_long(int index) {
340 // Invalidate the previous local if it contains first half of
341 // a double or long value since it's seconf half is being overwritten.
342 int prev_index = index - 1;
343 if (prev_index >= 0 &&
344 (is_double(type_at(local(prev_index))) ||
345 is_long(type_at(local(prev_index))))) {
346 set_type_at(local(prev_index), bottom_type());
347 }
348 }
349
350 void load_local_object(int index) {
351 ciType* type = type_at(local(index));
352 assert(is_reference(type), "must be reference type");
353 push(type);
354 }
355 void store_local_object(int index) {
356 ciType* type = pop_value();
357 assert(is_reference(type) || type->is_return_address(),
358 "must be reference type or return address");
359 overwrite_local_double_long(index);
360 set_type_at(local(index), type);
361 }
362
363 void load_local_double(int index) {
364 ciType* type = type_at(local(index));
365 ciType* type2 = type_at(local(index+1));
366 assert(is_double(type), "must be double type");
367 assert(type2 == double2_type(), "must be 2nd half");
368 push(type);
369 push(double2_type());
370 }
371 void store_local_double(int index) {
372 ciType* type2 = pop_value();
373 ciType* type = pop_value();
374 assert(is_double(type), "must be double");
375 assert(type2 == double2_type(), "must be 2nd half");
376 overwrite_local_double_long(index);
377 set_type_at(local(index), type);
378 set_type_at(local(index+1), type2);
379 }
380
381 void load_local_float(int index) {
382 ciType* type = type_at(local(index));
383 assert(is_float(type), "must be float type");
384 push(type);
385 }
386 void store_local_float(int index) {
387 ciType* type = pop_value();
388 assert(is_float(type), "must be float type");
389 overwrite_local_double_long(index);
390 set_type_at(local(index), type);
391 }
392
393 void load_local_int(int index) {
394 ciType* type = type_at(local(index));
395 assert(is_int(type), "must be int type");
396 push(type);
397 }
398 void store_local_int(int index) {
399 ciType* type = pop_value();
400 assert(is_int(type), "must be int type");
401 overwrite_local_double_long(index);
402 set_type_at(local(index), type);
403 }
404
405 void load_local_long(int index) {
406 ciType* type = type_at(local(index));
407 ciType* type2 = type_at(local(index+1));
408 assert(is_long(type), "must be long type");
409 assert(type2 == long2_type(), "must be 2nd half");
410 push(type);
411 push(long2_type());
412 }
413 void store_local_long(int index) {
414 ciType* type2 = pop_value();
415 ciType* type = pop_value();
416 assert(is_long(type), "must be long");
417 assert(type2 == long2_type(), "must be 2nd half");
418 overwrite_local_double_long(index);
419 set_type_at(local(index), type);
420 set_type_at(local(index+1), type2);
421 }
422
423 // Stop interpretation of this path with a trap.
424 void trap(ciBytecodeStream* str, ciKlass* klass, int index);
425
426 public:
427 StateVector(ciTypeFlow* outer);
428
429 // Copy our value into some other StateVector
430 void copy_into(StateVector* copy) const;
431
432 // Meets this StateVector with another, destructively modifying this
433 // one. Returns true if any modification takes place.
434 bool meet(const StateVector* incoming);
435
436 // Ditto, except that the incoming state is coming from an exception.
437 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming);
438
439 // Apply the effect of one bytecode to this StateVector
440 bool apply_one_bytecode(ciBytecodeStream* stream);
441
442 // What is the bci of the trap?
443 int trap_bci() { return _trap_bci; }
444
445 // What is the index associated with the trap?
446 int trap_index() { return _trap_index; }
447
448 void print_cell_on(outputStream* st, Cell c) const PRODUCT_RETURN;
449 void print_on(outputStream* st) const PRODUCT_RETURN;
450 };
451
452 // Parameter for "find_block" calls:
453 // Describes the difference between a public and private copy.
454 enum CreateOption {
455 create_public_copy,
456 create_private_copy,
457 no_create
458 };
459
460 // A basic block
461 class Block : public ResourceObj {
462 private:
463 ciBlock* _ciblock;
464 GrowableArray<Block*>* _exceptions;
465 GrowableArray<ciInstanceKlass*>* _exc_klasses;
466 GrowableArray<Block*>* _successors;
467 StateVector* _state;
468 JsrSet* _jsrs;
469
470 int _trap_bci;
471 int _trap_index;
472
473 // A reasonable approximation to pre-order, provided.to the client.
474 int _pre_order;
475
476 // Has this block been cloned for some special purpose?
477 bool _private_copy;
478
479 // A pointer used for our internal work list
480 Block* _next;
481 bool _on_work_list;
482
483 ciBlock* ciblock() const { return _ciblock; }
484 StateVector* state() const { return _state; }
485
486 // Compute the exceptional successors and types for this Block.
487 void compute_exceptions();
488
489 public:
490 // constructors
491 Block(ciTypeFlow* outer, ciBlock* ciblk, JsrSet* jsrs);
492
493 void set_trap(int trap_bci, int trap_index) {
494 _trap_bci = trap_bci;
495 _trap_index = trap_index;
496 assert(has_trap(), "");
497 }
498 bool has_trap() const { return _trap_bci != -1; }
499 int trap_bci() const { assert(has_trap(), ""); return _trap_bci; }
500 int trap_index() const { assert(has_trap(), ""); return _trap_index; }
501
502 // accessors
503 ciTypeFlow* outer() const { return state()->outer(); }
504 int start() const { return _ciblock->start_bci(); }
505 int limit() const { return _ciblock->limit_bci(); }
506 int control() const { return _ciblock->control_bci(); }
507
508 bool is_private_copy() const { return _private_copy; }
509 void set_private_copy(bool z);
510 int private_copy_count() const { return outer()->private_copy_count(ciblock()->index(), _jsrs); }
511
512 // access to entry state
513 int stack_size() const { return _state->stack_size(); }
514 int monitor_count() const { return _state->monitor_count(); }
515 ciType* local_type_at(int i) const { return _state->local_type_at(i); }
516 ciType* stack_type_at(int i) const { return _state->stack_type_at(i); }
517
518 // Get the successors for this Block.
519 GrowableArray<Block*>* successors(ciBytecodeStream* str,
520 StateVector* state,
521 JsrSet* jsrs);
522 GrowableArray<Block*>* successors() {
523 assert(_successors != NULL, "must be filled in");
524 return _successors;
525 }
526
527 // Helper function for "successors" when making private copies of
528 // loop heads for C2.
529 Block * clone_loop_head(ciTypeFlow* analyzer,
530 int branch_bci,
531 Block* target,
532 JsrSet* jsrs);
533
534 // Get the exceptional successors for this Block.
535 GrowableArray<Block*>* exceptions() {
536 if (_exceptions == NULL) {
537 compute_exceptions();
538 }
539 return _exceptions;
540 }
541
542 // Get the exception klasses corresponding to the
543 // exceptional successors for this Block.
544 GrowableArray<ciInstanceKlass*>* exc_klasses() {
545 if (_exc_klasses == NULL) {
546 compute_exceptions();
547 }
548 return _exc_klasses;
549 }
550
551 // Is this Block compatible with a given JsrSet?
552 bool is_compatible_with(JsrSet* other) {
553 return _jsrs->is_compatible_with(other);
554 }
555
556 // Copy the value of our state vector into another.
557 void copy_state_into(StateVector* copy) const {
558 _state->copy_into(copy);
559 }
560
561 // Copy the value of our JsrSet into another
562 void copy_jsrs_into(JsrSet* copy) const {
563 _jsrs->copy_into(copy);
564 }
565
566 // Meets the start state of this block with another state, destructively
567 // modifying this one. Returns true if any modification takes place.
568 bool meet(const StateVector* incoming) {
569 return state()->meet(incoming);
570 }
571
572 // Ditto, except that the incoming state is coming from an
573 // exception path. This means the stack is replaced by the
574 // appropriate exception type.
575 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming) {
576 return state()->meet_exception(exc, incoming);
577 }
578
579 // Work list manipulation
580 void set_next(Block* block) { _next = block; }
581 Block* next() const { return _next; }
582
583 void set_on_work_list(bool c) { _on_work_list = c; }
584 bool is_on_work_list() const { return _on_work_list; }
585
586 bool has_pre_order() const { return _pre_order >= 0; }
587 void set_pre_order(int po) { assert(!has_pre_order() && po >= 0, ""); _pre_order = po; }
588 int pre_order() const { assert(has_pre_order(), ""); return _pre_order; }
589 bool is_start() const { return _pre_order == outer()->start_block_num(); }
590
591 // A ranking used in determining order within the work list.
592 bool is_simpler_than(Block* other);
593
594 void print_value_on(outputStream* st) const PRODUCT_RETURN;
595 void print_on(outputStream* st) const PRODUCT_RETURN;
596 };
597
598 // Standard indexes of successors, for various bytecodes.
599 enum {
600 FALL_THROUGH = 0, // normal control
601 IF_NOT_TAKEN = 0, // the not-taken branch of an if (i.e., fall-through)
602 IF_TAKEN = 1, // the taken branch of an if
603 GOTO_TARGET = 0, // unique successor for goto, jsr, or ret
604 SWITCH_DEFAULT = 0, // default branch of a switch
605 SWITCH_CASES = 1 // first index for any non-default switch branches
606 // Unlike in other blocks, the successors of a switch are listed uniquely.
607 };
608
609 private:
610 // A mapping from pre_order to Blocks. This array is created
611 // only at the end of the flow.
612 Block** _block_map;
613
614 // For each ciBlock index, a list of Blocks which share this ciBlock.
615 GrowableArray<Block*>** _idx_to_blocklist;
616 // count of ciBlocks
617 int _ciblock_count;
618
619 // Tells if a given instruction is able to generate an exception edge.
620 bool can_trap(ciBytecodeStream& str);
621
622 public:
623 // Return the block beginning at bci which has a JsrSet compatible
624 // with jsrs.
625 Block* block_at(int bci, JsrSet* set, CreateOption option = create_public_copy);
626
627 // block factory
628 Block* get_block_for(int ciBlockIndex, JsrSet* jsrs, CreateOption option = create_public_copy);
629
630 // How many of the blocks have the private_copy bit set?
631 int private_copy_count(int ciBlockIndex, JsrSet* jsrs) const;
632
633 // Return an existing block containing bci which has a JsrSet compatible
634 // with jsrs, or NULL if there is none.
635 Block* existing_block_at(int bci, JsrSet* set) { return block_at(bci, set, no_create); }
636
637 // Tell whether the flow analysis has encountered an error of some sort.
638 bool failing() { return env()->failing() || _failure_reason != NULL; }
639
640 // Reason this compilation is failing, such as "too many basic blocks".
641 const char* failure_reason() { return _failure_reason; }
642
643 // Note a failure.
644 void record_failure(const char* reason);
645
646 // Return the block of a given pre-order number.
647 int have_block_count() const { return _block_map != NULL; }
648 int block_count() const { assert(have_block_count(), "");
649 return _next_pre_order; }
650 Block* pre_order_at(int po) const { assert(0 <= po && po < block_count(), "out of bounds");
651 return _block_map[po]; }
652 Block* start_block() const { return pre_order_at(start_block_num()); }
653 int start_block_num() const { return 0; }
654
655 private:
656 // A work list used during flow analysis.
657 Block* _work_list;
658
659 // Next Block::_pre_order. After mapping, doubles as block_count.
660 int _next_pre_order;
661
662 // Are there more blocks on the work list?
663 bool work_list_empty() { return _work_list == NULL; }
664
665 // Get the next basic block from our work list.
666 Block* work_list_next();
667
668 // Add a basic block to our work list.
669 void add_to_work_list(Block* block);
670
671 // State used for make_jsr_record
672 int _jsr_count;
673 GrowableArray<JsrRecord*>* _jsr_records;
674
675 public:
676 // Make a JsrRecord for a given (entry, return) pair, if such a record
677 // does not already exist.
678 JsrRecord* make_jsr_record(int entry_address, int return_address);
679
680 private:
681 // Get the initial state for start_bci:
682 const StateVector* get_start_state();
683
684 // Merge the current state into all exceptional successors at the
685 // current point in the code.
686 void flow_exceptions(GrowableArray<Block*>* exceptions,
687 GrowableArray<ciInstanceKlass*>* exc_klasses,
688 StateVector* state);
689
690 // Merge the current state into all successors at the current point
691 // in the code.
692 void flow_successors(GrowableArray<Block*>* successors,
693 StateVector* state);
694
695 // Interpret the effects of the bytecodes on the incoming state
696 // vector of a basic block. Push the changed state to succeeding
697 // basic blocks.
698 void flow_block(Block* block,
699 StateVector* scratch_state,
700 JsrSet* scratch_jsrs);
701
702 // Perform the type flow analysis, creating and cloning Blocks as
703 // necessary.
704 void flow_types();
705
706 // Create the block map, which indexes blocks in pre_order.
707 void map_blocks();
708
709 public:
710 // Perform type inference flow analysis.
711 void do_flow();
712
713 void print_on(outputStream* st) const PRODUCT_RETURN;
714 };