Thu, 13 Jan 2011 22:15:41 -0800
4926272: methodOopDesc::method_from_bcp is unsafe
Reviewed-by: coleenp, jrose, kvn, dcubed
1 /*
2 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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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).
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23 */
25 #ifndef SHARE_VM_CI_CITYPEFLOW_HPP
26 #define SHARE_VM_CI_CITYPEFLOW_HPP
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 #endif
40 class ciTypeFlow : public ResourceObj {
41 private:
42 ciEnv* _env;
43 ciMethod* _method;
44 ciMethodBlocks* _methodBlocks;
45 int _osr_bci;
47 // information cached from the method:
48 int _max_locals;
49 int _max_stack;
50 int _code_size;
51 bool _has_irreducible_entry;
53 const char* _failure_reason;
55 public:
56 class StateVector;
57 class Loop;
58 class Block;
60 // Build a type flow analyzer
61 // Do an OSR analysis if osr_bci >= 0.
62 ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci = InvocationEntryBci);
64 // Accessors
65 ciMethod* method() const { return _method; }
66 ciEnv* env() { return _env; }
67 Arena* arena() { return _env->arena(); }
68 bool is_osr_flow() const{ return _osr_bci != InvocationEntryBci; }
69 int start_bci() const { return is_osr_flow()? _osr_bci: 0; }
70 int max_locals() const { return _max_locals; }
71 int max_stack() const { return _max_stack; }
72 int max_cells() const { return _max_locals + _max_stack; }
73 int code_size() const { return _code_size; }
74 bool has_irreducible_entry() const { return _has_irreducible_entry; }
76 // Represents information about an "active" jsr call. This
77 // class represents a call to the routine at some entry address
78 // with some distinct return address.
79 class JsrRecord : public ResourceObj {
80 private:
81 int _entry_address;
82 int _return_address;
83 public:
84 JsrRecord(int entry_address, int return_address) {
85 _entry_address = entry_address;
86 _return_address = return_address;
87 }
89 int entry_address() const { return _entry_address; }
90 int return_address() const { return _return_address; }
92 void print_on(outputStream* st) const {
93 #ifndef PRODUCT
94 st->print("%d->%d", entry_address(), return_address());
95 #endif
96 }
97 };
99 // A JsrSet represents some set of JsrRecords. This class
100 // is used to record a set of all jsr routines which we permit
101 // execution to return (ret) from.
102 //
103 // During abstract interpretation, JsrSets are used to determine
104 // whether two paths which reach a given block are unique, and
105 // should be cloned apart, or are compatible, and should merge
106 // together.
107 //
108 // Note that different amounts of effort can be expended determining
109 // if paths are compatible. <DISCUSSION>
110 class JsrSet : public ResourceObj {
111 private:
112 GrowableArray<JsrRecord*>* _set;
114 JsrRecord* record_at(int i) {
115 return _set->at(i);
116 }
118 // Insert the given JsrRecord into the JsrSet, maintaining the order
119 // of the set and replacing any element with the same entry address.
120 void insert_jsr_record(JsrRecord* record);
122 // Remove the JsrRecord with the given return address from the JsrSet.
123 void remove_jsr_record(int return_address);
125 public:
126 JsrSet(Arena* arena, int default_len = 4);
128 // Copy this JsrSet.
129 void copy_into(JsrSet* jsrs);
131 // Is this JsrSet compatible with some other JsrSet?
132 bool is_compatible_with(JsrSet* other);
134 // Apply the effect of a single bytecode to the JsrSet.
135 void apply_control(ciTypeFlow* analyzer,
136 ciBytecodeStream* str,
137 StateVector* state);
139 // What is the cardinality of this set?
140 int size() const { return _set->length(); }
142 void print_on(outputStream* st) const PRODUCT_RETURN;
143 };
145 class LocalSet VALUE_OBJ_CLASS_SPEC {
146 private:
147 enum Constants { max = 63 };
148 uint64_t _bits;
149 public:
150 LocalSet() : _bits(0) {}
151 void add(uint32_t i) { if (i < (uint32_t)max) _bits |= (1LL << i); }
152 void add(LocalSet* ls) { _bits |= ls->_bits; }
153 bool test(uint32_t i) const { return i < (uint32_t)max ? (_bits>>i)&1U : true; }
154 void clear() { _bits = 0; }
155 void print_on(outputStream* st, int limit) const PRODUCT_RETURN;
156 };
158 // Used as a combined index for locals and temps
159 enum Cell {
160 Cell_0, Cell_max = INT_MAX
161 };
163 // A StateVector summarizes the type information at some
164 // point in the program
165 class StateVector : public ResourceObj {
166 private:
167 ciType** _types;
168 int _stack_size;
169 int _monitor_count;
170 ciTypeFlow* _outer;
172 int _trap_bci;
173 int _trap_index;
175 LocalSet _def_locals; // For entire block
177 static ciType* type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer);
179 public:
180 // Special elements in our type lattice.
181 enum {
182 T_TOP = T_VOID, // why not?
183 T_BOTTOM = T_CONFLICT,
184 T_LONG2 = T_SHORT, // 2nd word of T_LONG
185 T_DOUBLE2 = T_CHAR, // 2nd word of T_DOUBLE
186 T_NULL = T_BYTE // for now.
187 };
188 static ciType* top_type() { return ciType::make((BasicType)T_TOP); }
189 static ciType* bottom_type() { return ciType::make((BasicType)T_BOTTOM); }
190 static ciType* long2_type() { return ciType::make((BasicType)T_LONG2); }
191 static ciType* double2_type(){ return ciType::make((BasicType)T_DOUBLE2); }
192 static ciType* null_type() { return ciType::make((BasicType)T_NULL); }
194 static ciType* half_type(ciType* t) {
195 switch (t->basic_type()) {
196 case T_LONG: return long2_type();
197 case T_DOUBLE: return double2_type();
198 default: ShouldNotReachHere(); return NULL;
199 }
200 }
202 // The meet operation for our type lattice.
203 ciType* type_meet(ciType* t1, ciType* t2) {
204 return type_meet_internal(t1, t2, outer());
205 }
207 // Accessors
208 ciTypeFlow* outer() const { return _outer; }
210 int stack_size() const { return _stack_size; }
211 void set_stack_size(int ss) { _stack_size = ss; }
213 int monitor_count() const { return _monitor_count; }
214 void set_monitor_count(int mc) { _monitor_count = mc; }
216 LocalSet* def_locals() { return &_def_locals; }
217 const LocalSet* def_locals() const { return &_def_locals; }
219 static Cell start_cell() { return (Cell)0; }
220 static Cell next_cell(Cell c) { return (Cell)(((int)c) + 1); }
221 Cell limit_cell() const {
222 return (Cell)(outer()->max_locals() + stack_size());
223 }
225 // Cell creation
226 Cell local(int lnum) const {
227 assert(lnum < outer()->max_locals(), "index check");
228 return (Cell)(lnum);
229 }
231 Cell stack(int snum) const {
232 assert(snum < stack_size(), "index check");
233 return (Cell)(outer()->max_locals() + snum);
234 }
236 Cell tos() const { return stack(stack_size()-1); }
238 // For external use only:
239 ciType* local_type_at(int i) const { return type_at(local(i)); }
240 ciType* stack_type_at(int i) const { return type_at(stack(i)); }
242 // Accessors for the type of some Cell c
243 ciType* type_at(Cell c) const {
244 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
245 return _types[c];
246 }
248 void set_type_at(Cell c, ciType* type) {
249 assert(start_cell() <= c && c < limit_cell(), "out of bounds");
250 _types[c] = type;
251 }
253 // Top-of-stack operations.
254 void set_type_at_tos(ciType* type) { set_type_at(tos(), type); }
255 ciType* type_at_tos() const { return type_at(tos()); }
257 void push(ciType* type) {
258 _stack_size++;
259 set_type_at_tos(type);
260 }
261 void pop() {
262 debug_only(set_type_at_tos(bottom_type()));
263 _stack_size--;
264 }
265 ciType* pop_value() {
266 ciType* t = type_at_tos();
267 pop();
268 return t;
269 }
271 // Convenience operations.
272 bool is_reference(ciType* type) const {
273 return type == null_type() || !type->is_primitive_type();
274 }
275 bool is_int(ciType* type) const {
276 return type->basic_type() == T_INT;
277 }
278 bool is_long(ciType* type) const {
279 return type->basic_type() == T_LONG;
280 }
281 bool is_float(ciType* type) const {
282 return type->basic_type() == T_FLOAT;
283 }
284 bool is_double(ciType* type) const {
285 return type->basic_type() == T_DOUBLE;
286 }
288 void store_to_local(int lnum) {
289 _def_locals.add((uint) lnum);
290 }
292 void push_translate(ciType* type);
294 void push_int() {
295 push(ciType::make(T_INT));
296 }
297 void pop_int() {
298 assert(is_int(type_at_tos()), "must be integer");
299 pop();
300 }
301 void check_int(Cell c) {
302 assert(is_int(type_at(c)), "must be integer");
303 }
304 void push_double() {
305 push(ciType::make(T_DOUBLE));
306 push(double2_type());
307 }
308 void pop_double() {
309 assert(type_at_tos() == double2_type(), "must be 2nd half");
310 pop();
311 assert(is_double(type_at_tos()), "must be double");
312 pop();
313 }
314 void push_float() {
315 push(ciType::make(T_FLOAT));
316 }
317 void pop_float() {
318 assert(is_float(type_at_tos()), "must be float");
319 pop();
320 }
321 void push_long() {
322 push(ciType::make(T_LONG));
323 push(long2_type());
324 }
325 void pop_long() {
326 assert(type_at_tos() == long2_type(), "must be 2nd half");
327 pop();
328 assert(is_long(type_at_tos()), "must be long");
329 pop();
330 }
331 void push_object(ciKlass* klass) {
332 push(klass);
333 }
334 void pop_object() {
335 assert(is_reference(type_at_tos()), "must be reference type");
336 pop();
337 }
338 void pop_array() {
339 assert(type_at_tos() == null_type() ||
340 type_at_tos()->is_array_klass(), "must be array type");
341 pop();
342 }
343 // pop_objArray and pop_typeArray narrow the tos to ciObjArrayKlass
344 // or ciTypeArrayKlass (resp.). In the rare case that an explicit
345 // null is popped from the stack, we return NULL. Caller beware.
346 ciObjArrayKlass* pop_objArray() {
347 ciType* array = pop_value();
348 if (array == null_type()) return NULL;
349 assert(array->is_obj_array_klass(), "must be object array type");
350 return array->as_obj_array_klass();
351 }
352 ciTypeArrayKlass* pop_typeArray() {
353 ciType* array = pop_value();
354 if (array == null_type()) return NULL;
355 assert(array->is_type_array_klass(), "must be prim array type");
356 return array->as_type_array_klass();
357 }
358 void push_null() {
359 push(null_type());
360 }
361 void do_null_assert(ciKlass* unloaded_klass);
363 // Helper convenience routines.
364 void do_aaload(ciBytecodeStream* str);
365 void do_checkcast(ciBytecodeStream* str);
366 void do_getfield(ciBytecodeStream* str);
367 void do_getstatic(ciBytecodeStream* str);
368 void do_invoke(ciBytecodeStream* str, bool has_receiver);
369 void do_jsr(ciBytecodeStream* str);
370 void do_ldc(ciBytecodeStream* str);
371 void do_multianewarray(ciBytecodeStream* str);
372 void do_new(ciBytecodeStream* str);
373 void do_newarray(ciBytecodeStream* str);
374 void do_putfield(ciBytecodeStream* str);
375 void do_putstatic(ciBytecodeStream* str);
376 void do_ret(ciBytecodeStream* str);
378 void overwrite_local_double_long(int index) {
379 // Invalidate the previous local if it contains first half of
380 // a double or long value since it's seconf half is being overwritten.
381 int prev_index = index - 1;
382 if (prev_index >= 0 &&
383 (is_double(type_at(local(prev_index))) ||
384 is_long(type_at(local(prev_index))))) {
385 set_type_at(local(prev_index), bottom_type());
386 }
387 }
389 void load_local_object(int index) {
390 ciType* type = type_at(local(index));
391 assert(is_reference(type), "must be reference type");
392 push(type);
393 }
394 void store_local_object(int index) {
395 ciType* type = pop_value();
396 assert(is_reference(type) || type->is_return_address(),
397 "must be reference type or return address");
398 overwrite_local_double_long(index);
399 set_type_at(local(index), type);
400 store_to_local(index);
401 }
403 void load_local_double(int index) {
404 ciType* type = type_at(local(index));
405 ciType* type2 = type_at(local(index+1));
406 assert(is_double(type), "must be double type");
407 assert(type2 == double2_type(), "must be 2nd half");
408 push(type);
409 push(double2_type());
410 }
411 void store_local_double(int index) {
412 ciType* type2 = pop_value();
413 ciType* type = pop_value();
414 assert(is_double(type), "must be double");
415 assert(type2 == double2_type(), "must be 2nd half");
416 overwrite_local_double_long(index);
417 set_type_at(local(index), type);
418 set_type_at(local(index+1), type2);
419 store_to_local(index);
420 store_to_local(index+1);
421 }
423 void load_local_float(int index) {
424 ciType* type = type_at(local(index));
425 assert(is_float(type), "must be float type");
426 push(type);
427 }
428 void store_local_float(int index) {
429 ciType* type = pop_value();
430 assert(is_float(type), "must be float type");
431 overwrite_local_double_long(index);
432 set_type_at(local(index), type);
433 store_to_local(index);
434 }
436 void load_local_int(int index) {
437 ciType* type = type_at(local(index));
438 assert(is_int(type), "must be int type");
439 push(type);
440 }
441 void store_local_int(int index) {
442 ciType* type = pop_value();
443 assert(is_int(type), "must be int type");
444 overwrite_local_double_long(index);
445 set_type_at(local(index), type);
446 store_to_local(index);
447 }
449 void load_local_long(int index) {
450 ciType* type = type_at(local(index));
451 ciType* type2 = type_at(local(index+1));
452 assert(is_long(type), "must be long type");
453 assert(type2 == long2_type(), "must be 2nd half");
454 push(type);
455 push(long2_type());
456 }
457 void store_local_long(int index) {
458 ciType* type2 = pop_value();
459 ciType* type = pop_value();
460 assert(is_long(type), "must be long");
461 assert(type2 == long2_type(), "must be 2nd half");
462 overwrite_local_double_long(index);
463 set_type_at(local(index), type);
464 set_type_at(local(index+1), type2);
465 store_to_local(index);
466 store_to_local(index+1);
467 }
469 // Stop interpretation of this path with a trap.
470 void trap(ciBytecodeStream* str, ciKlass* klass, int index);
472 public:
473 StateVector(ciTypeFlow* outer);
475 // Copy our value into some other StateVector
476 void copy_into(StateVector* copy) const;
478 // Meets this StateVector with another, destructively modifying this
479 // one. Returns true if any modification takes place.
480 bool meet(const StateVector* incoming);
482 // Ditto, except that the incoming state is coming from an exception.
483 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming);
485 // Apply the effect of one bytecode to this StateVector
486 bool apply_one_bytecode(ciBytecodeStream* stream);
488 // What is the bci of the trap?
489 int trap_bci() { return _trap_bci; }
491 // What is the index associated with the trap?
492 int trap_index() { return _trap_index; }
494 void print_cell_on(outputStream* st, Cell c) const PRODUCT_RETURN;
495 void print_on(outputStream* st) const PRODUCT_RETURN;
496 };
498 // Parameter for "find_block" calls:
499 // Describes the difference between a public and backedge copy.
500 enum CreateOption {
501 create_public_copy,
502 create_backedge_copy,
503 no_create
504 };
506 // Successor iterator
507 class SuccIter : public StackObj {
508 private:
509 Block* _pred;
510 int _index;
511 Block* _succ;
512 public:
513 SuccIter() : _pred(NULL), _index(-1), _succ(NULL) {}
514 SuccIter(Block* pred) : _pred(pred), _index(-1), _succ(NULL) { next(); }
515 int index() { return _index; }
516 Block* pred() { return _pred; } // Return predecessor
517 bool done() { return _index < 0; } // Finished?
518 Block* succ() { return _succ; } // Return current successor
519 void next(); // Advance
520 void set_succ(Block* succ); // Update current successor
521 bool is_normal_ctrl() { return index() < _pred->successors()->length(); }
522 };
524 // A basic block
525 class Block : public ResourceObj {
526 private:
527 ciBlock* _ciblock;
528 GrowableArray<Block*>* _exceptions;
529 GrowableArray<ciInstanceKlass*>* _exc_klasses;
530 GrowableArray<Block*>* _successors;
531 StateVector* _state;
532 JsrSet* _jsrs;
534 int _trap_bci;
535 int _trap_index;
537 // pre_order, assigned at first visit. Used as block ID and "visited" tag
538 int _pre_order;
540 // A post-order, used to compute the reverse post order (RPO) provided to the client
541 int _post_order; // used to compute rpo
543 // Has this block been cloned for a loop backedge?
544 bool _backedge_copy;
546 // A pointer used for our internal work list
547 Block* _next;
548 bool _on_work_list; // on the work list
549 Block* _rpo_next; // Reverse post order list
551 // Loop info
552 Loop* _loop; // nearest loop
553 bool _irreducible_entry; // entry to irreducible loop
554 bool _exception_entry; // entry to exception handler
556 ciBlock* ciblock() const { return _ciblock; }
557 StateVector* state() const { return _state; }
559 // Compute the exceptional successors and types for this Block.
560 void compute_exceptions();
562 public:
563 // constructors
564 Block(ciTypeFlow* outer, ciBlock* ciblk, JsrSet* jsrs);
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; }
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; }
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); }
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); }
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(); }
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 }
615 // Get the exceptional successors for this Block.
616 GrowableArray<Block*>* exceptions() {
617 if (_exceptions == NULL) {
618 compute_exceptions();
619 }
620 return _exceptions;
621 }
623 // Get the exception klasses corresponding to the
624 // exceptional successors for this Block.
625 GrowableArray<ciInstanceKlass*>* exc_klasses() {
626 if (_exc_klasses == NULL) {
627 compute_exceptions();
628 }
629 return _exc_klasses;
630 }
632 // Is this Block compatible with a given JsrSet?
633 bool is_compatible_with(JsrSet* other) {
634 return _jsrs->is_compatible_with(other);
635 }
637 // Copy the value of our state vector into another.
638 void copy_state_into(StateVector* copy) const {
639 _state->copy_into(copy);
640 }
642 // Copy the value of our JsrSet into another
643 void copy_jsrs_into(JsrSet* copy) const {
644 _jsrs->copy_into(copy);
645 }
647 // Meets the start state of this block with another state, destructively
648 // modifying this one. Returns true if any modification takes place.
649 bool meet(const StateVector* incoming) {
650 return state()->meet(incoming);
651 }
653 // Ditto, except that the incoming state is coming from an
654 // exception path. This means the stack is replaced by the
655 // appropriate exception type.
656 bool meet_exception(ciInstanceKlass* exc, const StateVector* incoming) {
657 return state()->meet_exception(exc, incoming);
658 }
660 // Work list manipulation
661 void set_next(Block* block) { _next = block; }
662 Block* next() const { return _next; }
664 void set_on_work_list(bool c) { _on_work_list = c; }
665 bool is_on_work_list() const { return _on_work_list; }
667 bool has_pre_order() const { return _pre_order >= 0; }
668 void set_pre_order(int po) { assert(!has_pre_order(), ""); _pre_order = po; }
669 int pre_order() const { assert(has_pre_order(), ""); return _pre_order; }
670 void set_next_pre_order() { set_pre_order(outer()->inc_next_pre_order()); }
671 bool is_start() const { return _pre_order == outer()->start_block_num(); }
673 // Reverse post order
674 void df_init();
675 bool has_post_order() const { return _post_order >= 0; }
676 void set_post_order(int po) { assert(!has_post_order() && po >= 0, ""); _post_order = po; }
677 void reset_post_order(int o){ _post_order = o; }
678 int post_order() const { assert(has_post_order(), ""); return _post_order; }
680 bool has_rpo() const { return has_post_order() && outer()->have_block_count(); }
681 int rpo() const { assert(has_rpo(), ""); return outer()->block_count() - post_order() - 1; }
682 void set_rpo_next(Block* b) { _rpo_next = b; }
683 Block* rpo_next() { return _rpo_next; }
685 // Loops
686 Loop* loop() const { return _loop; }
687 void set_loop(Loop* lp) { _loop = lp; }
688 bool is_loop_head() const { return _loop && _loop->head() == this; }
689 void set_irreducible_entry(bool c) { _irreducible_entry = c; }
690 bool is_irreducible_entry() const { return _irreducible_entry; }
691 bool is_visited() const { return has_pre_order(); }
692 bool is_post_visited() const { return has_post_order(); }
693 bool is_clonable_exit(Loop* lp);
694 Block* looping_succ(Loop* lp); // Successor inside of loop
695 bool is_single_entry_loop_head() const {
696 if (!is_loop_head()) return false;
697 for (Loop* lp = loop(); lp != NULL && lp->head() == this; lp = lp->parent())
698 if (lp->is_irreducible()) return false;
699 return true;
700 }
702 void print_value_on(outputStream* st) const PRODUCT_RETURN;
703 void print_on(outputStream* st) const PRODUCT_RETURN;
704 };
706 // Loop
707 class Loop : public ResourceObj {
708 private:
709 Loop* _parent;
710 Loop* _sibling; // List of siblings, null terminated
711 Loop* _child; // Head of child list threaded thru sibling pointer
712 Block* _head; // Head of loop
713 Block* _tail; // Tail of loop
714 bool _irreducible;
715 LocalSet _def_locals;
717 public:
718 Loop(Block* head, Block* tail) :
719 _head(head), _tail(tail),
720 _parent(NULL), _sibling(NULL), _child(NULL),
721 _irreducible(false), _def_locals() {}
723 Loop* parent() const { return _parent; }
724 Loop* sibling() const { return _sibling; }
725 Loop* child() const { return _child; }
726 Block* head() const { return _head; }
727 Block* tail() const { return _tail; }
728 void set_parent(Loop* p) { _parent = p; }
729 void set_sibling(Loop* s) { _sibling = s; }
730 void set_child(Loop* c) { _child = c; }
731 void set_head(Block* hd) { _head = hd; }
732 void set_tail(Block* tl) { _tail = tl; }
734 int depth() const; // nesting depth
736 // Returns true if lp is a nested loop or us.
737 bool contains(Loop* lp) const;
738 bool contains(Block* blk) const { return contains(blk->loop()); }
740 // Data flow on locals
741 LocalSet* def_locals() { return &_def_locals; }
742 const LocalSet* def_locals() const { return &_def_locals; }
744 // Merge the branch lp into this branch, sorting on the loop head
745 // pre_orders. Returns the new branch.
746 Loop* sorted_merge(Loop* lp);
748 // Mark non-single entry to loop
749 void set_irreducible(Block* entry) {
750 _irreducible = true;
751 entry->set_irreducible_entry(true);
752 }
753 bool is_irreducible() const { return _irreducible; }
755 bool is_root() const { return _tail->pre_order() == max_jint; }
757 void print(outputStream* st = tty, int indent = 0) const PRODUCT_RETURN;
758 };
760 // Postorder iteration over the loop tree.
761 class PostorderLoops : public StackObj {
762 private:
763 Loop* _root;
764 Loop* _current;
765 public:
766 PostorderLoops(Loop* root) : _root(root), _current(root) {
767 while (_current->child() != NULL) {
768 _current = _current->child();
769 }
770 }
771 bool done() { return _current == NULL; } // Finished iterating?
772 void next(); // Advance to next loop
773 Loop* current() { return _current; } // Return current loop.
774 };
776 // Preorder iteration over the loop tree.
777 class PreorderLoops : public StackObj {
778 private:
779 Loop* _root;
780 Loop* _current;
781 public:
782 PreorderLoops(Loop* root) : _root(root), _current(root) {}
783 bool done() { return _current == NULL; } // Finished iterating?
784 void next(); // Advance to next loop
785 Loop* current() { return _current; } // Return current loop.
786 };
788 // Standard indexes of successors, for various bytecodes.
789 enum {
790 FALL_THROUGH = 0, // normal control
791 IF_NOT_TAKEN = 0, // the not-taken branch of an if (i.e., fall-through)
792 IF_TAKEN = 1, // the taken branch of an if
793 GOTO_TARGET = 0, // unique successor for goto, jsr, or ret
794 SWITCH_DEFAULT = 0, // default branch of a switch
795 SWITCH_CASES = 1 // first index for any non-default switch branches
796 // Unlike in other blocks, the successors of a switch are listed uniquely.
797 };
799 private:
800 // A mapping from pre_order to Blocks. This array is created
801 // only at the end of the flow.
802 Block** _block_map;
804 // For each ciBlock index, a list of Blocks which share this ciBlock.
805 GrowableArray<Block*>** _idx_to_blocklist;
806 // count of ciBlocks
807 int _ciblock_count;
809 // Tells if a given instruction is able to generate an exception edge.
810 bool can_trap(ciBytecodeStream& str);
812 // Clone the loop heads. Returns true if any cloning occurred.
813 bool clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
815 // Clone lp's head and replace tail's successors with clone.
816 Block* clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set);
818 public:
819 // Return the block beginning at bci which has a JsrSet compatible
820 // with jsrs.
821 Block* block_at(int bci, JsrSet* set, CreateOption option = create_public_copy);
823 // block factory
824 Block* get_block_for(int ciBlockIndex, JsrSet* jsrs, CreateOption option = create_public_copy);
826 // How many of the blocks have the backedge_copy bit set?
827 int backedge_copy_count(int ciBlockIndex, JsrSet* jsrs) const;
829 // Return an existing block containing bci which has a JsrSet compatible
830 // with jsrs, or NULL if there is none.
831 Block* existing_block_at(int bci, JsrSet* set) { return block_at(bci, set, no_create); }
833 // Tell whether the flow analysis has encountered an error of some sort.
834 bool failing() { return env()->failing() || _failure_reason != NULL; }
836 // Reason this compilation is failing, such as "too many basic blocks".
837 const char* failure_reason() { return _failure_reason; }
839 // Note a failure.
840 void record_failure(const char* reason);
842 // Return the block of a given pre-order number.
843 int have_block_count() const { return _block_map != NULL; }
844 int block_count() const { assert(have_block_count(), "");
845 return _next_pre_order; }
846 Block* pre_order_at(int po) const { assert(0 <= po && po < block_count(), "out of bounds");
847 return _block_map[po]; }
848 Block* start_block() const { return pre_order_at(start_block_num()); }
849 int start_block_num() const { return 0; }
850 Block* rpo_at(int rpo) const { assert(0 <= rpo && rpo < block_count(), "out of bounds");
851 return _block_map[rpo]; }
852 int next_pre_order() { return _next_pre_order; }
853 int inc_next_pre_order() { return _next_pre_order++; }
855 private:
856 // A work list used during flow analysis.
857 Block* _work_list;
859 // List of blocks in reverse post order
860 Block* _rpo_list;
862 // Next Block::_pre_order. After mapping, doubles as block_count.
863 int _next_pre_order;
865 // Are there more blocks on the work list?
866 bool work_list_empty() { return _work_list == NULL; }
868 // Get the next basic block from our work list.
869 Block* work_list_next();
871 // Add a basic block to our work list.
872 void add_to_work_list(Block* block);
874 // Prepend a basic block to rpo list.
875 void prepend_to_rpo_list(Block* blk) {
876 blk->set_rpo_next(_rpo_list);
877 _rpo_list = blk;
878 }
880 // Root of the loop tree
881 Loop* _loop_tree_root;
883 // State used for make_jsr_record
884 int _jsr_count;
885 GrowableArray<JsrRecord*>* _jsr_records;
887 public:
888 // Make a JsrRecord for a given (entry, return) pair, if such a record
889 // does not already exist.
890 JsrRecord* make_jsr_record(int entry_address, int return_address);
892 void set_loop_tree_root(Loop* ltr) { _loop_tree_root = ltr; }
893 Loop* loop_tree_root() { return _loop_tree_root; }
895 private:
896 // Get the initial state for start_bci:
897 const StateVector* get_start_state();
899 // Merge the current state into all exceptional successors at the
900 // current point in the code.
901 void flow_exceptions(GrowableArray<Block*>* exceptions,
902 GrowableArray<ciInstanceKlass*>* exc_klasses,
903 StateVector* state);
905 // Merge the current state into all successors at the current point
906 // in the code.
907 void flow_successors(GrowableArray<Block*>* successors,
908 StateVector* state);
910 // Interpret the effects of the bytecodes on the incoming state
911 // vector of a basic block. Push the changed state to succeeding
912 // basic blocks.
913 void flow_block(Block* block,
914 StateVector* scratch_state,
915 JsrSet* scratch_jsrs);
917 // Perform the type flow analysis, creating and cloning Blocks as
918 // necessary.
919 void flow_types();
921 // Perform the depth first type flow analysis. Helper for flow_types.
922 void df_flow_types(Block* start,
923 bool do_flow,
924 StateVector* temp_vector,
925 JsrSet* temp_set);
927 // Incrementally build loop tree.
928 void build_loop_tree(Block* blk);
930 // Create the block map, which indexes blocks in pre_order.
931 void map_blocks();
933 public:
934 // Perform type inference flow analysis.
935 void do_flow();
937 void print_on(outputStream* st) const PRODUCT_RETURN;
939 void rpo_print_on(outputStream* st) const PRODUCT_RETURN;
940 };
942 #endif // SHARE_VM_CI_CITYPEFLOW_HPP