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