1 /*
2 * Copyright (c) 1999, 2013, 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 #include "precompiled.hpp"
26 #include "c1/c1_Compilation.hpp"
27 #include "c1/c1_FrameMap.hpp"
28 #include "c1/c1_GraphBuilder.hpp"
29 #include "c1/c1_IR.hpp"
30 #include "c1/c1_InstructionPrinter.hpp"
31 #include "c1/c1_Optimizer.hpp"
32 #include "utilities/bitMap.inline.hpp"
33
34
35 // Implementation of XHandlers
36 //
37 // Note: This code could eventually go away if we are
38 // just using the ciExceptionHandlerStream.
39
40 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) {
41 ciExceptionHandlerStream s(method);
42 while (!s.is_done()) {
43 _list.append(new XHandler(s.handler()));
44 s.next();
45 }
46 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent");
47 }
48
49 // deep copy of all XHandler contained in list
50 XHandlers::XHandlers(XHandlers* other) :
51 _list(other->length())
52 {
53 for (int i = 0; i < other->length(); i++) {
54 _list.append(new XHandler(other->handler_at(i)));
55 }
56 }
57
58 // Returns whether a particular exception type can be caught. Also
59 // returns true if klass is unloaded or any exception handler
60 // classes are unloaded. type_is_exact indicates whether the throw
61 // is known to be exactly that class or it might throw a subtype.
62 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const {
63 // the type is unknown so be conservative
64 if (!klass->is_loaded()) {
65 return true;
66 }
67
68 for (int i = 0; i < length(); i++) {
69 XHandler* handler = handler_at(i);
70 if (handler->is_catch_all()) {
71 // catch of ANY
72 return true;
73 }
74 ciInstanceKlass* handler_klass = handler->catch_klass();
75 // if it's unknown it might be catchable
76 if (!handler_klass->is_loaded()) {
77 return true;
78 }
79 // if the throw type is definitely a subtype of the catch type
80 // then it can be caught.
81 if (klass->is_subtype_of(handler_klass)) {
82 return true;
83 }
84 if (!type_is_exact) {
85 // If the type isn't exactly known then it can also be caught by
86 // catch statements where the inexact type is a subtype of the
87 // catch type.
88 // given: foo extends bar extends Exception
89 // throw bar can be caught by catch foo, catch bar, and catch
90 // Exception, however it can't be caught by any handlers without
91 // bar in its type hierarchy.
92 if (handler_klass->is_subtype_of(klass)) {
93 return true;
94 }
95 }
96 }
97
98 return false;
99 }
100
101
102 bool XHandlers::equals(XHandlers* others) const {
103 if (others == NULL) return false;
104 if (length() != others->length()) return false;
105
106 for (int i = 0; i < length(); i++) {
107 if (!handler_at(i)->equals(others->handler_at(i))) return false;
108 }
109 return true;
110 }
111
112 bool XHandler::equals(XHandler* other) const {
113 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco");
114
115 if (entry_pco() != other->entry_pco()) return false;
116 if (scope_count() != other->scope_count()) return false;
117 if (_desc != other->_desc) return false;
118
119 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal");
120 return true;
121 }
122
123
124 // Implementation of IRScope
125 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) {
126 GraphBuilder gm(compilation, this);
127 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats());
128 if (compilation->bailed_out()) return NULL;
129 return gm.start();
130 }
131
132
133 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph)
134 : _callees(2)
135 , _compilation(compilation)
136 , _requires_phi_function(method->max_locals())
137 {
138 _caller = caller;
139 _level = caller == NULL ? 0 : caller->level() + 1;
140 _method = method;
141 _xhandlers = new XHandlers(method);
142 _number_of_locks = 0;
143 _monitor_pairing_ok = method->has_balanced_monitors();
144 _wrote_final = false;
145 _wrote_fields = false;
146 _start = NULL;
147
148 if (osr_bci == -1) {
149 _requires_phi_function.clear();
150 } else {
151 // selective creation of phi functions is not possibel in osr-methods
152 _requires_phi_function.set_range(0, method->max_locals());
153 }
154
155 assert(method->holder()->is_loaded() , "method holder must be loaded");
156
157 // build graph if monitor pairing is ok
158 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci);
159 }
160
161
162 int IRScope::max_stack() const {
163 int my_max = method()->max_stack();
164 int callee_max = 0;
165 for (int i = 0; i < number_of_callees(); i++) {
166 callee_max = MAX2(callee_max, callee_no(i)->max_stack());
167 }
168 return my_max + callee_max;
169 }
170
171
172 bool IRScopeDebugInfo::should_reexecute() {
173 ciMethod* cur_method = scope()->method();
174 int cur_bci = bci();
175 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) {
176 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
177 return Interpreter::bytecode_should_reexecute(code);
178 } else
179 return false;
180 }
181
182
183 // Implementation of CodeEmitInfo
184
185 // Stack must be NON-null
186 CodeEmitInfo::CodeEmitInfo(ValueStack* stack, XHandlers* exception_handlers, bool deoptimize_on_exception)
187 : _scope(stack->scope())
188 , _scope_debug_info(NULL)
189 , _oop_map(NULL)
190 , _stack(stack)
191 , _exception_handlers(exception_handlers)
192 , _is_method_handle_invoke(false)
193 , _deoptimize_on_exception(deoptimize_on_exception) {
194 assert(_stack != NULL, "must be non null");
195 }
196
197
198 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, ValueStack* stack)
199 : _scope(info->_scope)
200 , _exception_handlers(NULL)
201 , _scope_debug_info(NULL)
202 , _oop_map(NULL)
203 , _stack(stack == NULL ? info->_stack : stack)
204 , _is_method_handle_invoke(info->_is_method_handle_invoke)
205 , _deoptimize_on_exception(info->_deoptimize_on_exception) {
206
207 // deep copy of exception handlers
208 if (info->_exception_handlers != NULL) {
209 _exception_handlers = new XHandlers(info->_exception_handlers);
210 }
211 }
212
213
214 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) {
215 // record the safepoint before recording the debug info for enclosing scopes
216 recorder->add_safepoint(pc_offset, _oop_map->deep_copy());
217 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke);
218 recorder->end_safepoint(pc_offset);
219 }
220
221
222 void CodeEmitInfo::add_register_oop(LIR_Opr opr) {
223 assert(_oop_map != NULL, "oop map must already exist");
224 assert(opr->is_single_cpu(), "should not call otherwise");
225
226 VMReg name = frame_map()->regname(opr);
227 _oop_map->set_oop(name);
228 }
229
230
231
232
233 // Implementation of IR
234
235 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) :
236 _locals_size(in_WordSize(-1))
237 , _num_loops(0) {
238 // setup IR fields
239 _compilation = compilation;
240 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true);
241 _code = NULL;
242 }
243
244
245 void IR::optimize_blocks() {
246 Optimizer opt(this);
247 if (!compilation()->profile_branches()) {
248 if (DoCEE) {
249 opt.eliminate_conditional_expressions();
250 #ifndef PRODUCT
251 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); }
252 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); }
253 #endif
254 }
255 if (EliminateBlocks) {
256 opt.eliminate_blocks();
257 #ifndef PRODUCT
258 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); }
259 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); }
260 #endif
261 }
262 }
263 }
264
265 void IR::eliminate_null_checks() {
266 Optimizer opt(this);
267 if (EliminateNullChecks) {
268 opt.eliminate_null_checks();
269 #ifndef PRODUCT
270 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); }
271 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); }
272 #endif
273 }
274 }
275
276
277 static int sort_pairs(BlockPair** a, BlockPair** b) {
278 if ((*a)->from() == (*b)->from()) {
279 return (*a)->to()->block_id() - (*b)->to()->block_id();
280 } else {
281 return (*a)->from()->block_id() - (*b)->from()->block_id();
282 }
283 }
284
285
286 class CriticalEdgeFinder: public BlockClosure {
287 BlockPairList blocks;
288 IR* _ir;
289
290 public:
291 CriticalEdgeFinder(IR* ir): _ir(ir) {}
292 void block_do(BlockBegin* bb) {
293 BlockEnd* be = bb->end();
294 int nos = be->number_of_sux();
295 if (nos >= 2) {
296 for (int i = 0; i < nos; i++) {
297 BlockBegin* sux = be->sux_at(i);
298 if (sux->number_of_preds() >= 2) {
299 blocks.append(new BlockPair(bb, sux));
300 }
301 }
302 }
303 }
304
305 void split_edges() {
306 BlockPair* last_pair = NULL;
307 blocks.sort(sort_pairs);
308 for (int i = 0; i < blocks.length(); i++) {
309 BlockPair* pair = blocks.at(i);
310 if (last_pair != NULL && pair->is_same(last_pair)) continue;
311 BlockBegin* from = pair->from();
312 BlockBegin* to = pair->to();
313 BlockBegin* split = from->insert_block_between(to);
314 #ifndef PRODUCT
315 if ((PrintIR || PrintIR1) && Verbose) {
316 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)",
317 from->block_id(), to->block_id(), split->block_id());
318 }
319 #endif
320 last_pair = pair;
321 }
322 }
323 };
324
325 void IR::split_critical_edges() {
326 CriticalEdgeFinder cef(this);
327
328 iterate_preorder(&cef);
329 cef.split_edges();
330 }
331
332
333 class UseCountComputer: public ValueVisitor, BlockClosure {
334 private:
335 void visit(Value* n) {
336 // Local instructions and Phis for expression stack values at the
337 // start of basic blocks are not added to the instruction list
338 if (!(*n)->is_linked() && (*n)->can_be_linked()) {
339 assert(false, "a node was not appended to the graph");
340 Compilation::current()->bailout("a node was not appended to the graph");
341 }
342 // use n's input if not visited before
343 if (!(*n)->is_pinned() && !(*n)->has_uses()) {
344 // note: a) if the instruction is pinned, it will be handled by compute_use_count
345 // b) if the instruction has uses, it was touched before
346 // => in both cases we don't need to update n's values
347 uses_do(n);
348 }
349 // use n
350 (*n)->_use_count++;
351 }
352
353 Values* worklist;
354 int depth;
355 enum {
356 max_recurse_depth = 20
357 };
358
359 void uses_do(Value* n) {
360 depth++;
361 if (depth > max_recurse_depth) {
362 // don't allow the traversal to recurse too deeply
363 worklist->push(*n);
364 } else {
365 (*n)->input_values_do(this);
366 // special handling for some instructions
367 if ((*n)->as_BlockEnd() != NULL) {
368 // note on BlockEnd:
369 // must 'use' the stack only if the method doesn't
370 // terminate, however, in those cases stack is empty
371 (*n)->state_values_do(this);
372 }
373 }
374 depth--;
375 }
376
377 void block_do(BlockBegin* b) {
378 depth = 0;
379 // process all pinned nodes as the roots of expression trees
380 for (Instruction* n = b; n != NULL; n = n->next()) {
381 if (n->is_pinned()) uses_do(&n);
382 }
383 assert(depth == 0, "should have counted back down");
384
385 // now process any unpinned nodes which recursed too deeply
386 while (worklist->length() > 0) {
387 Value t = worklist->pop();
388 if (!t->is_pinned()) {
389 // compute the use count
390 uses_do(&t);
391
392 // pin the instruction so that LIRGenerator doesn't recurse
393 // too deeply during it's evaluation.
394 t->pin();
395 }
396 }
397 assert(depth == 0, "should have counted back down");
398 }
399
400 UseCountComputer() {
401 worklist = new Values();
402 depth = 0;
403 }
404
405 public:
406 static void compute(BlockList* blocks) {
407 UseCountComputer ucc;
408 blocks->iterate_backward(&ucc);
409 }
410 };
411
412
413 // helper macro for short definition of trace-output inside code
414 #ifndef PRODUCT
415 #define TRACE_LINEAR_SCAN(level, code) \
416 if (TraceLinearScanLevel >= level) { \
417 code; \
418 }
419 #else
420 #define TRACE_LINEAR_SCAN(level, code)
421 #endif
422
423 class ComputeLinearScanOrder : public StackObj {
424 private:
425 int _max_block_id; // the highest block_id of a block
426 int _num_blocks; // total number of blocks (smaller than _max_block_id)
427 int _num_loops; // total number of loops
428 bool _iterative_dominators;// method requires iterative computation of dominatiors
429
430 BlockList* _linear_scan_order; // the resulting list of blocks in correct order
431
432 BitMap _visited_blocks; // used for recursive processing of blocks
433 BitMap _active_blocks; // used for recursive processing of blocks
434 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator
435 intArray _forward_branches; // number of incoming forward branches for each block
436 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges
437 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop
438 BlockList _work_list; // temporary list (used in mark_loops and compute_order)
439 BlockList _loop_headers;
440
441 Compilation* _compilation;
442
443 // accessors for _visited_blocks and _active_blocks
444 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); }
445 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); }
446 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); }
447 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); }
448 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); }
449 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); }
450
451 // accessors for _forward_branches
452 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); }
453 int dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); }
454
455 // accessors for _loop_map
456 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); }
457 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); }
458 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); }
459
460 // count edges between blocks
461 void count_edges(BlockBegin* cur, BlockBegin* parent);
462
463 // loop detection
464 void mark_loops();
465 void clear_non_natural_loops(BlockBegin* start_block);
466 void assign_loop_depth(BlockBegin* start_block);
467
468 // computation of final block order
469 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b);
470 void compute_dominator(BlockBegin* cur, BlockBegin* parent);
471 int compute_weight(BlockBegin* cur);
472 bool ready_for_processing(BlockBegin* cur);
473 void sort_into_work_list(BlockBegin* b);
474 void append_block(BlockBegin* cur);
475 void compute_order(BlockBegin* start_block);
476
477 // fixup of dominators for non-natural loops
478 bool compute_dominators_iter();
479 void compute_dominators();
480
481 // debug functions
482 NOT_PRODUCT(void print_blocks();)
483 DEBUG_ONLY(void verify();)
484
485 Compilation* compilation() const { return _compilation; }
486 public:
487 ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block);
488
489 // accessors for final result
490 BlockList* linear_scan_order() const { return _linear_scan_order; }
491 int num_loops() const { return _num_loops; }
492 };
493
494
495 ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block) :
496 _max_block_id(BlockBegin::number_of_blocks()),
497 _num_blocks(0),
498 _num_loops(0),
499 _iterative_dominators(false),
500 _visited_blocks(_max_block_id),
501 _active_blocks(_max_block_id),
502 _dominator_blocks(_max_block_id),
503 _forward_branches(_max_block_id, 0),
504 _loop_end_blocks(8),
505 _work_list(8),
506 _linear_scan_order(NULL), // initialized later with correct size
507 _loop_map(0, 0), // initialized later with correct size
508 _compilation(c)
509 {
510 TRACE_LINEAR_SCAN(2, tty->print_cr("***** computing linear-scan block order"));
511
512 init_visited();
513 count_edges(start_block, NULL);
514
515 if (compilation()->is_profiling()) {
516 ciMethod *method = compilation()->method();
517 if (!method->is_accessor()) {
518 ciMethodData* md = method->method_data_or_null();
519 assert(md != NULL, "Sanity");
520 md->set_compilation_stats(_num_loops, _num_blocks);
521 }
522 }
523
524 if (_num_loops > 0) {
525 mark_loops();
526 clear_non_natural_loops(start_block);
527 assign_loop_depth(start_block);
528 }
529
530 compute_order(start_block);
531 compute_dominators();
532
533 NOT_PRODUCT(print_blocks());
534 DEBUG_ONLY(verify());
535 }
536
537
538 // Traverse the CFG:
539 // * count total number of blocks
540 // * count all incoming edges and backward incoming edges
541 // * number loop header blocks
542 // * create a list with all loop end blocks
543 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) {
544 TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1));
545 assert(cur->dominator() == NULL, "dominator already initialized");
546
547 if (is_active(cur)) {
548 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch"));
549 assert(is_visited(cur), "block must be visisted when block is active");
550 assert(parent != NULL, "must have parent");
551
552 cur->set(BlockBegin::linear_scan_loop_header_flag);
553 cur->set(BlockBegin::backward_branch_target_flag);
554
555 parent->set(BlockBegin::linear_scan_loop_end_flag);
556
557 // When a loop header is also the start of an exception handler, then the backward branch is
558 // an exception edge. Because such edges are usually critical edges which cannot be split, the
559 // loop must be excluded here from processing.
560 if (cur->is_set(BlockBegin::exception_entry_flag)) {
561 // Make sure that dominators are correct in this weird situation
562 _iterative_dominators = true;
563 return;
564 }
565 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur,
566 "loop end blocks must have one successor (critical edges are split)");
567
568 _loop_end_blocks.append(parent);
569 return;
570 }
571
572 // increment number of incoming forward branches
573 inc_forward_branches(cur);
574
575 if (is_visited(cur)) {
576 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited"));
577 return;
578 }
579
580 _num_blocks++;
581 set_visited(cur);
582 set_active(cur);
583
584 // recursive call for all successors
585 int i;
586 for (i = cur->number_of_sux() - 1; i >= 0; i--) {
587 count_edges(cur->sux_at(i), cur);
588 }
589 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
590 count_edges(cur->exception_handler_at(i), cur);
591 }
592
593 clear_active(cur);
594
595 // Each loop has a unique number.
596 // When multiple loops are nested, assign_loop_depth assumes that the
597 // innermost loop has the lowest number. This is guaranteed by setting
598 // the loop number after the recursive calls for the successors above
599 // have returned.
600 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) {
601 assert(cur->loop_index() == -1, "cannot set loop-index twice");
602 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops));
603
604 cur->set_loop_index(_num_loops);
605 _loop_headers.append(cur);
606 _num_loops++;
607 }
608
609 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id()));
610 }
611
612
613 void ComputeLinearScanOrder::mark_loops() {
614 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops"));
615
616 _loop_map = BitMap2D(_num_loops, _max_block_id);
617 _loop_map.clear();
618
619 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) {
620 BlockBegin* loop_end = _loop_end_blocks.at(i);
621 BlockBegin* loop_start = loop_end->sux_at(0);
622 int loop_idx = loop_start->loop_index();
623
624 TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx));
625 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set");
626 assert(loop_end->number_of_sux() == 1, "incorrect number of successors");
627 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set");
628 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set");
629 assert(_work_list.is_empty(), "work list must be empty before processing");
630
631 // add the end-block of the loop to the working list
632 _work_list.push(loop_end);
633 set_block_in_loop(loop_idx, loop_end);
634 do {
635 BlockBegin* cur = _work_list.pop();
636
637 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id()));
638 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list");
639
640 // recursive processing of all predecessors ends when start block of loop is reached
641 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) {
642 for (int j = cur->number_of_preds() - 1; j >= 0; j--) {
643 BlockBegin* pred = cur->pred_at(j);
644
645 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) {
646 // this predecessor has not been processed yet, so add it to work list
647 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id()));
648 _work_list.push(pred);
649 set_block_in_loop(loop_idx, pred);
650 }
651 }
652 }
653 } while (!_work_list.is_empty());
654 }
655 }
656
657
658 // check for non-natural loops (loops where the loop header does not dominate
659 // all other loop blocks = loops with mulitple entries).
660 // such loops are ignored
661 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) {
662 for (int i = _num_loops - 1; i >= 0; i--) {
663 if (is_block_in_loop(i, start_block)) {
664 // loop i contains the entry block of the method
665 // -> this is not a natural loop, so ignore it
666 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i));
667
668 BlockBegin *loop_header = _loop_headers.at(i);
669 assert(loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Must be loop header");
670
671 for (int j = 0; j < loop_header->number_of_preds(); j++) {
672 BlockBegin *pred = loop_header->pred_at(j);
673 pred->clear(BlockBegin::linear_scan_loop_end_flag);
674 }
675
676 loop_header->clear(BlockBegin::linear_scan_loop_header_flag);
677
678 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) {
679 clear_block_in_loop(i, block_id);
680 }
681 _iterative_dominators = true;
682 }
683 }
684 }
685
686 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) {
687 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing loop-depth and weight"));
688 init_visited();
689
690 assert(_work_list.is_empty(), "work list must be empty before processing");
691 _work_list.append(start_block);
692
693 do {
694 BlockBegin* cur = _work_list.pop();
695
696 if (!is_visited(cur)) {
697 set_visited(cur);
698 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id()));
699
700 // compute loop-depth and loop-index for the block
701 assert(cur->loop_depth() == 0, "cannot set loop-depth twice");
702 int i;
703 int loop_depth = 0;
704 int min_loop_idx = -1;
705 for (i = _num_loops - 1; i >= 0; i--) {
706 if (is_block_in_loop(i, cur)) {
707 loop_depth++;
708 min_loop_idx = i;
709 }
710 }
711 cur->set_loop_depth(loop_depth);
712 cur->set_loop_index(min_loop_idx);
713
714 // append all unvisited successors to work list
715 for (i = cur->number_of_sux() - 1; i >= 0; i--) {
716 _work_list.append(cur->sux_at(i));
717 }
718 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
719 _work_list.append(cur->exception_handler_at(i));
720 }
721 }
722 } while (!_work_list.is_empty());
723 }
724
725
726 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) {
727 assert(a != NULL && b != NULL, "must have input blocks");
728
729 _dominator_blocks.clear();
730 while (a != NULL) {
731 _dominator_blocks.set_bit(a->block_id());
732 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized");
733 a = a->dominator();
734 }
735 while (b != NULL && !_dominator_blocks.at(b->block_id())) {
736 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized");
737 b = b->dominator();
738 }
739
740 assert(b != NULL, "could not find dominator");
741 return b;
742 }
743
744 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) {
745 if (cur->dominator() == NULL) {
746 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id()));
747 cur->set_dominator(parent);
748
749 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) {
750 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id()));
751 // Does not hold for exception blocks
752 assert(cur->number_of_preds() > 1 || cur->is_set(BlockBegin::exception_entry_flag), "");
753 cur->set_dominator(common_dominator(cur->dominator(), parent));
754 }
755
756 // Additional edge to xhandler of all our successors
757 // range check elimination needs that the state at the end of a
758 // block be valid in every block it dominates so cur must dominate
759 // the exception handlers of its successors.
760 int num_cur_xhandler = cur->number_of_exception_handlers();
761 for (int j = 0; j < num_cur_xhandler; j++) {
762 BlockBegin* xhandler = cur->exception_handler_at(j);
763 compute_dominator(xhandler, parent);
764 }
765 }
766
767
768 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) {
769 BlockBegin* single_sux = NULL;
770 if (cur->number_of_sux() == 1) {
771 single_sux = cur->sux_at(0);
772 }
773
774 // limit loop-depth to 15 bit (only for security reason, it will never be so big)
775 int weight = (cur->loop_depth() & 0x7FFF) << 16;
776
777 // general macro for short definition of weight flags
778 // the first instance of INC_WEIGHT_IF has the highest priority
779 int cur_bit = 15;
780 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--;
781
782 // this is necessery for the (very rare) case that two successing blocks have
783 // the same loop depth, but a different loop index (can happen for endless loops
784 // with exception handlers)
785 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag));
786
787 // loop end blocks (blocks that end with a backward branch) are added
788 // after all other blocks of the loop.
789 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag));
790
791 // critical edge split blocks are prefered because than they have a bigger
792 // proability to be completely empty
793 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag));
794
795 // exceptions should not be thrown in normal control flow, so these blocks
796 // are added as late as possible
797 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL));
798 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL));
799
800 // exceptions handlers are added as late as possible
801 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag));
802
803 // guarantee that weight is > 0
804 weight |= 1;
805
806 #undef INC_WEIGHT_IF
807 assert(cur_bit >= 0, "too many flags");
808 assert(weight > 0, "weight cannot become negative");
809
810 return weight;
811 }
812
813 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) {
814 // Discount the edge just traveled.
815 // When the number drops to zero, all forward branches were processed
816 if (dec_forward_branches(cur) != 0) {
817 return false;
818 }
819
820 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)");
821 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)");
822 return true;
823 }
824
825 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) {
826 assert(_work_list.index_of(cur) == -1, "block already in work list");
827
828 int cur_weight = compute_weight(cur);
829
830 // the linear_scan_number is used to cache the weight of a block
831 cur->set_linear_scan_number(cur_weight);
832
833 #ifndef PRODUCT
834 if (StressLinearScan) {
835 _work_list.insert_before(0, cur);
836 return;
837 }
838 #endif
839
840 _work_list.append(NULL); // provide space for new element
841
842 int insert_idx = _work_list.length() - 1;
843 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) {
844 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1));
845 insert_idx--;
846 }
847 _work_list.at_put(insert_idx, cur);
848
849 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id()));
850 TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number()));
851
852 #ifdef ASSERT
853 for (int i = 0; i < _work_list.length(); i++) {
854 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set");
855 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist");
856 }
857 #endif
858 }
859
860 void ComputeLinearScanOrder::append_block(BlockBegin* cur) {
861 TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number()));
862 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice");
863
864 // currently, the linear scan order and code emit order are equal.
865 // therefore the linear_scan_number and the weight of a block must also
866 // be equal.
867 cur->set_linear_scan_number(_linear_scan_order->length());
868 _linear_scan_order->append(cur);
869 }
870
871 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) {
872 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing final block order"));
873
874 // the start block is always the first block in the linear scan order
875 _linear_scan_order = new BlockList(_num_blocks);
876 append_block(start_block);
877
878 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction");
879 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry();
880 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry();
881
882 BlockBegin* sux_of_osr_entry = NULL;
883 if (osr_entry != NULL) {
884 // special handling for osr entry:
885 // ignore the edge between the osr entry and its successor for processing
886 // the osr entry block is added manually below
887 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor");
888 assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow");
889
890 sux_of_osr_entry = osr_entry->sux_at(0);
891 dec_forward_branches(sux_of_osr_entry);
892
893 compute_dominator(osr_entry, start_block);
894 _iterative_dominators = true;
895 }
896 compute_dominator(std_entry, start_block);
897
898 // start processing with standard entry block
899 assert(_work_list.is_empty(), "list must be empty before processing");
900
901 if (ready_for_processing(std_entry)) {
902 sort_into_work_list(std_entry);
903 } else {
904 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)");
905 }
906
907 do {
908 BlockBegin* cur = _work_list.pop();
909
910 if (cur == sux_of_osr_entry) {
911 // the osr entry block is ignored in normal processing, it is never added to the
912 // work list. Instead, it is added as late as possible manually here.
913 append_block(osr_entry);
914 compute_dominator(cur, osr_entry);
915 }
916 append_block(cur);
917
918 int i;
919 int num_sux = cur->number_of_sux();
920 // changed loop order to get "intuitive" order of if- and else-blocks
921 for (i = 0; i < num_sux; i++) {
922 BlockBegin* sux = cur->sux_at(i);
923 compute_dominator(sux, cur);
924 if (ready_for_processing(sux)) {
925 sort_into_work_list(sux);
926 }
927 }
928 num_sux = cur->number_of_exception_handlers();
929 for (i = 0; i < num_sux; i++) {
930 BlockBegin* sux = cur->exception_handler_at(i);
931 if (ready_for_processing(sux)) {
932 sort_into_work_list(sux);
933 }
934 }
935 } while (_work_list.length() > 0);
936 }
937
938
939 bool ComputeLinearScanOrder::compute_dominators_iter() {
940 bool changed = false;
941 int num_blocks = _linear_scan_order->length();
942
943 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator");
944 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors");
945 for (int i = 1; i < num_blocks; i++) {
946 BlockBegin* block = _linear_scan_order->at(i);
947
948 BlockBegin* dominator = block->pred_at(0);
949 int num_preds = block->number_of_preds();
950
951 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: Processing B%d", block->block_id()));
952
953 for (int j = 0; j < num_preds; j++) {
954
955 BlockBegin *pred = block->pred_at(j);
956 TRACE_LINEAR_SCAN(4, tty->print_cr(" DOM: Subrocessing B%d", pred->block_id()));
957
958 if (block->is_set(BlockBegin::exception_entry_flag)) {
959 dominator = common_dominator(dominator, pred);
960 int num_pred_preds = pred->number_of_preds();
961 for (int k = 0; k < num_pred_preds; k++) {
962 dominator = common_dominator(dominator, pred->pred_at(k));
963 }
964 } else {
965 dominator = common_dominator(dominator, pred);
966 }
967 }
968
969 if (dominator != block->dominator()) {
970 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id()));
971
972 block->set_dominator(dominator);
973 changed = true;
974 }
975 }
976 return changed;
977 }
978
979 void ComputeLinearScanOrder::compute_dominators() {
980 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators));
981
982 // iterative computation of dominators is only required for methods with non-natural loops
983 // and OSR-methods. For all other methods, the dominators computed when generating the
984 // linear scan block order are correct.
985 if (_iterative_dominators) {
986 do {
987 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation"));
988 } while (compute_dominators_iter());
989 }
990
991 // check that dominators are correct
992 assert(!compute_dominators_iter(), "fix point not reached");
993
994 // Add Blocks to dominates-Array
995 int num_blocks = _linear_scan_order->length();
996 for (int i = 0; i < num_blocks; i++) {
997 BlockBegin* block = _linear_scan_order->at(i);
998
999 BlockBegin *dom = block->dominator();
1000 if (dom) {
1001 assert(dom->dominator_depth() != -1, "Dominator must have been visited before");
1002 dom->dominates()->append(block);
1003 block->set_dominator_depth(dom->dominator_depth() + 1);
1004 } else {
1005 block->set_dominator_depth(0);
1006 }
1007 }
1008 }
1009
1010
1011 #ifndef PRODUCT
1012 void ComputeLinearScanOrder::print_blocks() {
1013 if (TraceLinearScanLevel >= 2) {
1014 tty->print_cr("----- loop information:");
1015 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
1016 BlockBegin* cur = _linear_scan_order->at(block_idx);
1017
1018 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id());
1019 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
1020 tty->print ("%d ", is_block_in_loop(loop_idx, cur));
1021 }
1022 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth());
1023 }
1024 }
1025
1026 if (TraceLinearScanLevel >= 1) {
1027 tty->print_cr("----- linear-scan block order:");
1028 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
1029 BlockBegin* cur = _linear_scan_order->at(block_idx);
1030 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth());
1031
1032 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " ");
1033 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " ");
1034 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " ");
1035 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " ");
1036
1037 if (cur->dominator() != NULL) {
1038 tty->print(" dom: B%d ", cur->dominator()->block_id());
1039 } else {
1040 tty->print(" dom: NULL ");
1041 }
1042
1043 if (cur->number_of_preds() > 0) {
1044 tty->print(" preds: ");
1045 for (int j = 0; j < cur->number_of_preds(); j++) {
1046 BlockBegin* pred = cur->pred_at(j);
1047 tty->print("B%d ", pred->block_id());
1048 }
1049 }
1050 if (cur->number_of_sux() > 0) {
1051 tty->print(" sux: ");
1052 for (int j = 0; j < cur->number_of_sux(); j++) {
1053 BlockBegin* sux = cur->sux_at(j);
1054 tty->print("B%d ", sux->block_id());
1055 }
1056 }
1057 if (cur->number_of_exception_handlers() > 0) {
1058 tty->print(" ex: ");
1059 for (int j = 0; j < cur->number_of_exception_handlers(); j++) {
1060 BlockBegin* ex = cur->exception_handler_at(j);
1061 tty->print("B%d ", ex->block_id());
1062 }
1063 }
1064 tty->cr();
1065 }
1066 }
1067 }
1068 #endif
1069
1070 #ifdef ASSERT
1071 void ComputeLinearScanOrder::verify() {
1072 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list");
1073
1074 if (StressLinearScan) {
1075 // blocks are scrambled when StressLinearScan is used
1076 return;
1077 }
1078
1079 // check that all successors of a block have a higher linear-scan-number
1080 // and that all predecessors of a block have a lower linear-scan-number
1081 // (only backward branches of loops are ignored)
1082 int i;
1083 for (i = 0; i < _linear_scan_order->length(); i++) {
1084 BlockBegin* cur = _linear_scan_order->at(i);
1085
1086 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number");
1087 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number");
1088
1089 int j;
1090 for (j = cur->number_of_sux() - 1; j >= 0; j--) {
1091 BlockBegin* sux = cur->sux_at(j);
1092
1093 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number");
1094 if (!sux->is_set(BlockBegin::backward_branch_target_flag)) {
1095 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order");
1096 }
1097 if (cur->loop_depth() == sux->loop_depth()) {
1098 assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index");
1099 }
1100 }
1101
1102 for (j = cur->number_of_preds() - 1; j >= 0; j--) {
1103 BlockBegin* pred = cur->pred_at(j);
1104
1105 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number");
1106 if (!cur->is_set(BlockBegin::backward_branch_target_flag)) {
1107 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order");
1108 }
1109 if (cur->loop_depth() == pred->loop_depth()) {
1110 assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index");
1111 }
1112
1113 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors");
1114 }
1115
1116 // check dominator
1117 if (i == 0) {
1118 assert(cur->dominator() == NULL, "first block has no dominator");
1119 } else {
1120 assert(cur->dominator() != NULL, "all but first block must have dominator");
1121 }
1122 // Assertion does not hold for exception handlers
1123 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0) || cur->is_set(BlockBegin::exception_entry_flag), "Single predecessor must also be dominator");
1124 }
1125
1126 // check that all loops are continuous
1127 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
1128 int block_idx = 0;
1129 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop");
1130
1131 // skip blocks before the loop
1132 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
1133 block_idx++;
1134 }
1135 // skip blocks of loop
1136 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
1137 block_idx++;
1138 }
1139 // after the first non-loop block, there must not be another loop-block
1140 while (block_idx < _num_blocks) {
1141 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order");
1142 block_idx++;
1143 }
1144 }
1145 }
1146 #endif
1147
1148
1149 void IR::compute_code() {
1150 assert(is_valid(), "IR must be valid");
1151
1152 ComputeLinearScanOrder compute_order(compilation(), start());
1153 _num_loops = compute_order.num_loops();
1154 _code = compute_order.linear_scan_order();
1155 }
1156
1157
1158 void IR::compute_use_counts() {
1159 // make sure all values coming out of this block get evaluated.
1160 int num_blocks = _code->length();
1161 for (int i = 0; i < num_blocks; i++) {
1162 _code->at(i)->end()->state()->pin_stack_for_linear_scan();
1163 }
1164
1165 // compute use counts
1166 UseCountComputer::compute(_code);
1167 }
1168
1169
1170 void IR::iterate_preorder(BlockClosure* closure) {
1171 assert(is_valid(), "IR must be valid");
1172 start()->iterate_preorder(closure);
1173 }
1174
1175
1176 void IR::iterate_postorder(BlockClosure* closure) {
1177 assert(is_valid(), "IR must be valid");
1178 start()->iterate_postorder(closure);
1179 }
1180
1181 void IR::iterate_linear_scan_order(BlockClosure* closure) {
1182 linear_scan_order()->iterate_forward(closure);
1183 }
1184
1185
1186 #ifndef PRODUCT
1187 class BlockPrinter: public BlockClosure {
1188 private:
1189 InstructionPrinter* _ip;
1190 bool _cfg_only;
1191 bool _live_only;
1192
1193 public:
1194 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) {
1195 _ip = ip;
1196 _cfg_only = cfg_only;
1197 _live_only = live_only;
1198 }
1199
1200 virtual void block_do(BlockBegin* block) {
1201 if (_cfg_only) {
1202 _ip->print_instr(block); tty->cr();
1203 } else {
1204 block->print_block(*_ip, _live_only);
1205 }
1206 }
1207 };
1208
1209
1210 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) {
1211 ttyLocker ttyl;
1212 InstructionPrinter ip(!cfg_only);
1213 BlockPrinter bp(&ip, cfg_only, live_only);
1214 start->iterate_preorder(&bp);
1215 tty->cr();
1216 }
1217
1218 void IR::print(bool cfg_only, bool live_only) {
1219 if (is_valid()) {
1220 print(start(), cfg_only, live_only);
1221 } else {
1222 tty->print_cr("invalid IR");
1223 }
1224 }
1225
1226
1227 define_array(BlockListArray, BlockList*)
1228 define_stack(BlockListList, BlockListArray)
1229
1230 class PredecessorValidator : public BlockClosure {
1231 private:
1232 BlockListList* _predecessors;
1233 BlockList* _blocks;
1234
1235 static int cmp(BlockBegin** a, BlockBegin** b) {
1236 return (*a)->block_id() - (*b)->block_id();
1237 }
1238
1239 public:
1240 PredecessorValidator(IR* hir) {
1241 ResourceMark rm;
1242 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL);
1243 _blocks = new BlockList();
1244
1245 int i;
1246 hir->start()->iterate_preorder(this);
1247 if (hir->code() != NULL) {
1248 assert(hir->code()->length() == _blocks->length(), "must match");
1249 for (i = 0; i < _blocks->length(); i++) {
1250 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists");
1251 }
1252 }
1253
1254 for (i = 0; i < _blocks->length(); i++) {
1255 BlockBegin* block = _blocks->at(i);
1256 BlockList* preds = _predecessors->at(block->block_id());
1257 if (preds == NULL) {
1258 assert(block->number_of_preds() == 0, "should be the same");
1259 continue;
1260 }
1261
1262 // clone the pred list so we can mutate it
1263 BlockList* pred_copy = new BlockList();
1264 int j;
1265 for (j = 0; j < block->number_of_preds(); j++) {
1266 pred_copy->append(block->pred_at(j));
1267 }
1268 // sort them in the same order
1269 preds->sort(cmp);
1270 pred_copy->sort(cmp);
1271 int length = MIN2(preds->length(), block->number_of_preds());
1272 for (j = 0; j < block->number_of_preds(); j++) {
1273 assert(preds->at(j) == pred_copy->at(j), "must match");
1274 }
1275
1276 assert(preds->length() == block->number_of_preds(), "should be the same");
1277 }
1278 }
1279
1280 virtual void block_do(BlockBegin* block) {
1281 _blocks->append(block);
1282 BlockEnd* be = block->end();
1283 int n = be->number_of_sux();
1284 int i;
1285 for (i = 0; i < n; i++) {
1286 BlockBegin* sux = be->sux_at(i);
1287 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler");
1288
1289 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
1290 if (preds == NULL) {
1291 preds = new BlockList();
1292 _predecessors->at_put(sux->block_id(), preds);
1293 }
1294 preds->append(block);
1295 }
1296
1297 n = block->number_of_exception_handlers();
1298 for (i = 0; i < n; i++) {
1299 BlockBegin* sux = block->exception_handler_at(i);
1300 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler");
1301
1302 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
1303 if (preds == NULL) {
1304 preds = new BlockList();
1305 _predecessors->at_put(sux->block_id(), preds);
1306 }
1307 preds->append(block);
1308 }
1309 }
1310 };
1311
1312 class VerifyBlockBeginField : public BlockClosure {
1313
1314 public:
1315
1316 virtual void block_do(BlockBegin *block) {
1317 for ( Instruction *cur = block; cur != NULL; cur = cur->next()) {
1318 assert(cur->block() == block, "Block begin is not correct");
1319 }
1320 }
1321 };
1322
1323 void IR::verify() {
1324 #ifdef ASSERT
1325 PredecessorValidator pv(this);
1326 VerifyBlockBeginField verifier;
1327 this->iterate_postorder(&verifier);
1328 #endif
1329 }
1330
1331 #endif // PRODUCT
1332
1333 void SubstitutionResolver::visit(Value* v) {
1334 Value v0 = *v;
1335 if (v0) {
1336 Value vs = v0->subst();
1337 if (vs != v0) {
1338 *v = v0->subst();
1339 }
1340 }
1341 }
1342
1343 #ifdef ASSERT
1344 class SubstitutionChecker: public ValueVisitor {
1345 void visit(Value* v) {
1346 Value v0 = *v;
1347 if (v0) {
1348 Value vs = v0->subst();
1349 assert(vs == v0, "missed substitution");
1350 }
1351 }
1352 };
1353 #endif
1354
1355
1356 void SubstitutionResolver::block_do(BlockBegin* block) {
1357 Instruction* last = NULL;
1358 for (Instruction* n = block; n != NULL;) {
1359 n->values_do(this);
1360 // need to remove this instruction from the instruction stream
1361 if (n->subst() != n) {
1362 assert(last != NULL, "must have last");
1363 last->set_next(n->next());
1364 } else {
1365 last = n;
1366 }
1367 n = last->next();
1368 }
1369
1370 #ifdef ASSERT
1371 SubstitutionChecker check_substitute;
1372 if (block->state()) block->state()->values_do(&check_substitute);
1373 block->block_values_do(&check_substitute);
1374 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute);
1375 #endif
1376 }