1 /*
2 * Copyright (c) 2009, 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 "compiler/compileLog.hpp"
27 #include "opto/addnode.hpp"
28 #include "opto/callGenerator.hpp"
29 #include "opto/callnode.hpp"
30 #include "opto/divnode.hpp"
31 #include "opto/graphKit.hpp"
32 #include "opto/idealKit.hpp"
33 #include "opto/rootnode.hpp"
34 #include "opto/runtime.hpp"
35 #include "opto/stringopts.hpp"
36 #include "opto/subnode.hpp"
37
38 #define __ kit.
39
40 class StringConcat : public ResourceObj {
41 private:
42 PhaseStringOpts* _stringopts;
43 Node* _string_alloc;
44 AllocateNode* _begin; // The allocation the begins the pattern
45 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
46 // SB.toString or or String.<init>(SB.toString)
47 bool _multiple; // indicates this is a fusion of two or more
48 // separate StringBuilders
49
50 Node* _arguments; // The list of arguments to be concatenated
51 GrowableArray<int> _mode; // into a String along with a mode flag
52 // indicating how to treat the value.
53 Node_List _constructors; // List of constructors (many in case of stacked concat)
54 Node_List _control; // List of control nodes that will be deleted
55 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
56 // to restart at the initial JVMState.
57
58 public:
59 // Mode for converting arguments to Strings
60 enum {
61 StringMode,
62 IntMode,
63 CharMode,
64 StringNullCheckMode
65 };
66
67 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
68 _end(end),
69 _begin(NULL),
70 _multiple(false),
71 _string_alloc(NULL),
72 _stringopts(stringopts) {
73 _arguments = new (_stringopts->C) Node(1);
74 _arguments->del_req(0);
75 }
76
77 bool validate_mem_flow();
78 bool validate_control_flow();
79
80 void merge_add() {
81 #if 0
82 // XXX This is place holder code for reusing an existing String
83 // allocation but the logic for checking the state safety is
84 // probably inadequate at the moment.
85 CallProjections endprojs;
86 sc->end()->extract_projections(&endprojs, false);
87 if (endprojs.resproj != NULL) {
88 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
89 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
90 if (use != NULL && use->method() != NULL &&
91 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
92 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
93 // Found useless new String(sb.toString()) so reuse the newly allocated String
94 // when creating the result instead of allocating a new one.
95 sc->set_string_alloc(use->in(TypeFunc::Parms));
96 sc->set_end(use);
97 }
98 }
99 }
100 #endif
101 }
102
103 StringConcat* merge(StringConcat* other, Node* arg);
104
105 void set_allocation(AllocateNode* alloc) {
106 _begin = alloc;
107 }
108
109 void append(Node* value, int mode) {
110 _arguments->add_req(value);
111 _mode.append(mode);
112 }
113 void push(Node* value, int mode) {
114 _arguments->ins_req(0, value);
115 _mode.insert_before(0, mode);
116 }
117
118 void push_string(Node* value) {
119 push(value, StringMode);
120 }
121 void push_string_null_check(Node* value) {
122 push(value, StringNullCheckMode);
123 }
124 void push_int(Node* value) {
125 push(value, IntMode);
126 }
127 void push_char(Node* value) {
128 push(value, CharMode);
129 }
130
131 static bool is_SB_toString(Node* call) {
132 if (call->is_CallStaticJava()) {
133 CallStaticJavaNode* csj = call->as_CallStaticJava();
134 ciMethod* m = csj->method();
135 if (m != NULL &&
136 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
137 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
138 return true;
139 }
140 }
141 return false;
142 }
143
144 static Node* skip_string_null_check(Node* value) {
145 // Look for a diamond shaped Null check of toString() result
146 // (could be code from String.valueOf()):
147 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
148 if (value->is_Phi()) {
149 int true_path = value->as_Phi()->is_diamond_phi();
150 if (true_path != 0) {
151 // phi->region->if_proj->ifnode->bool
152 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
153 Node* cmp = b->in(1);
154 Node* v1 = cmp->in(1);
155 Node* v2 = cmp->in(2);
156 // Null check of the return of toString which can simply be skipped.
157 if (b->_test._test == BoolTest::ne &&
158 v2->bottom_type() == TypePtr::NULL_PTR &&
159 value->in(true_path)->Opcode() == Op_CastPP &&
160 value->in(true_path)->in(1) == v1 &&
161 v1->is_Proj() && is_SB_toString(v1->in(0))) {
162 return v1;
163 }
164 }
165 }
166 return value;
167 }
168
169 Node* argument(int i) {
170 return _arguments->in(i);
171 }
172 Node* argument_uncast(int i) {
173 Node* arg = argument(i);
174 int amode = mode(i);
175 if (amode == StringConcat::StringMode ||
176 amode == StringConcat::StringNullCheckMode) {
177 arg = skip_string_null_check(arg);
178 }
179 return arg;
180 }
181 void set_argument(int i, Node* value) {
182 _arguments->set_req(i, value);
183 }
184 int num_arguments() {
185 return _mode.length();
186 }
187 int mode(int i) {
188 return _mode.at(i);
189 }
190 void add_control(Node* ctrl) {
191 assert(!_control.contains(ctrl), "only push once");
192 _control.push(ctrl);
193 }
194 void add_constructor(Node* init) {
195 assert(!_constructors.contains(init), "only push once");
196 _constructors.push(init);
197 }
198 CallStaticJavaNode* end() { return _end; }
199 AllocateNode* begin() { return _begin; }
200 Node* string_alloc() { return _string_alloc; }
201
202 void eliminate_unneeded_control();
203 void eliminate_initialize(InitializeNode* init);
204 void eliminate_call(CallNode* call);
205
206 void maybe_log_transform() {
207 CompileLog* log = _stringopts->C->log();
208 if (log != NULL) {
209 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
210 num_arguments(),
211 _string_alloc != NULL,
212 _multiple);
213 JVMState* p = _begin->jvms();
214 while (p != NULL) {
215 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
216 p = p->caller();
217 }
218 log->tail("replace_string_concat");
219 }
220 }
221
222 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
223 for (uint u = 0; u < _uncommon_traps.size(); u++) {
224 Node* uct = _uncommon_traps.at(u);
225
226 // Build a new call using the jvms state of the allocate
227 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
228 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
229 const TypePtr* no_memory_effects = NULL;
230 Compile* C = _stringopts->C;
231 CallStaticJavaNode* call = new (C) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
232 jvms->bci(), no_memory_effects);
233 for (int e = 0; e < TypeFunc::Parms; e++) {
234 call->init_req(e, uct->in(e));
235 }
236 // Set the trap request to record intrinsic failure if this trap
237 // is taken too many times. Ideally we would handle then traps by
238 // doing the original bookkeeping in the MDO so that if it caused
239 // the code to be thrown out we could still recompile and use the
240 // optimization. Failing the uncommon traps doesn't really mean
241 // that the optimization is a bad idea but there's no other way to
242 // do the MDO updates currently.
243 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
244 Deoptimization::Action_make_not_entrant);
245 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
246 kit.add_safepoint_edges(call);
247
248 _stringopts->gvn()->transform(call);
249 C->gvn_replace_by(uct, call);
250 uct->disconnect_inputs(NULL, C);
251 }
252 }
253
254 void cleanup() {
255 // disconnect the hook node
256 _arguments->disconnect_inputs(NULL, _stringopts->C);
257 }
258 };
259
260
261 void StringConcat::eliminate_unneeded_control() {
262 for (uint i = 0; i < _control.size(); i++) {
263 Node* n = _control.at(i);
264 if (n->is_Allocate()) {
265 eliminate_initialize(n->as_Allocate()->initialization());
266 }
267 if (n->is_Call()) {
268 if (n != _end) {
269 eliminate_call(n->as_Call());
270 }
271 } else if (n->is_IfTrue()) {
272 Compile* C = _stringopts->C;
273 C->gvn_replace_by(n, n->in(0)->in(0));
274 // get rid of the other projection
275 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
276 }
277 }
278 }
279
280
281 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
282 StringConcat* result = new StringConcat(_stringopts, _end);
283 for (uint x = 0; x < _control.size(); x++) {
284 Node* n = _control.at(x);
285 if (n->is_Call()) {
286 result->_control.push(n);
287 }
288 }
289 for (uint x = 0; x < other->_control.size(); x++) {
290 Node* n = other->_control.at(x);
291 if (n->is_Call()) {
292 result->_control.push(n);
293 }
294 }
295 assert(result->_control.contains(other->_end), "what?");
296 assert(result->_control.contains(_begin), "what?");
297 for (int x = 0; x < num_arguments(); x++) {
298 Node* argx = argument_uncast(x);
299 if (argx == arg) {
300 // replace the toString result with the all the arguments that
301 // made up the other StringConcat
302 for (int y = 0; y < other->num_arguments(); y++) {
303 result->append(other->argument(y), other->mode(y));
304 }
305 } else {
306 result->append(argx, mode(x));
307 }
308 }
309 result->set_allocation(other->_begin);
310 for (uint i = 0; i < _constructors.size(); i++) {
311 result->add_constructor(_constructors.at(i));
312 }
313 for (uint i = 0; i < other->_constructors.size(); i++) {
314 result->add_constructor(other->_constructors.at(i));
315 }
316 result->_multiple = true;
317 return result;
318 }
319
320
321 void StringConcat::eliminate_call(CallNode* call) {
322 Compile* C = _stringopts->C;
323 CallProjections projs;
324 call->extract_projections(&projs, false);
325 if (projs.fallthrough_catchproj != NULL) {
326 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
327 }
328 if (projs.fallthrough_memproj != NULL) {
329 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
330 }
331 if (projs.catchall_memproj != NULL) {
332 C->gvn_replace_by(projs.catchall_memproj, C->top());
333 }
334 if (projs.fallthrough_ioproj != NULL) {
335 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
336 }
337 if (projs.catchall_ioproj != NULL) {
338 C->gvn_replace_by(projs.catchall_ioproj, C->top());
339 }
340 if (projs.catchall_catchproj != NULL) {
341 // EA can't cope with the partially collapsed graph this
342 // creates so put it on the worklist to be collapsed later.
343 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
344 Node *use = i.get();
345 int opc = use->Opcode();
346 if (opc == Op_CreateEx || opc == Op_Region) {
347 _stringopts->record_dead_node(use);
348 }
349 }
350 C->gvn_replace_by(projs.catchall_catchproj, C->top());
351 }
352 if (projs.resproj != NULL) {
353 C->gvn_replace_by(projs.resproj, C->top());
354 }
355 C->gvn_replace_by(call, C->top());
356 }
357
358 void StringConcat::eliminate_initialize(InitializeNode* init) {
359 Compile* C = _stringopts->C;
360
361 // Eliminate Initialize node.
362 assert(init->outcnt() <= 2, "only a control and memory projection expected");
363 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
364 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
365 if (ctrl_proj != NULL) {
366 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
367 }
368 Node *mem_proj = init->proj_out(TypeFunc::Memory);
369 if (mem_proj != NULL) {
370 Node *mem = init->in(TypeFunc::Memory);
371 C->gvn_replace_by(mem_proj, mem);
372 }
373 C->gvn_replace_by(init, C->top());
374 init->disconnect_inputs(NULL, C);
375 }
376
377 Node_List PhaseStringOpts::collect_toString_calls() {
378 Node_List string_calls;
379 Node_List worklist;
380
381 _visited.Clear();
382
383 // Prime the worklist
384 for (uint i = 1; i < C->root()->len(); i++) {
385 Node* n = C->root()->in(i);
386 if (n != NULL && !_visited.test_set(n->_idx)) {
387 worklist.push(n);
388 }
389 }
390
391 while (worklist.size() > 0) {
392 Node* ctrl = worklist.pop();
393 if (StringConcat::is_SB_toString(ctrl)) {
394 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
395 string_calls.push(csj);
396 }
397 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
398 worklist.push(ctrl->in(0));
399 }
400 if (ctrl->is_Region()) {
401 for (uint i = 1; i < ctrl->len(); i++) {
402 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
403 worklist.push(ctrl->in(i));
404 }
405 }
406 }
407 }
408 return string_calls;
409 }
410
411
412 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
413 ciMethod* m = call->method();
414 ciSymbol* string_sig;
415 ciSymbol* int_sig;
416 ciSymbol* char_sig;
417 if (m->holder() == C->env()->StringBuilder_klass()) {
418 string_sig = ciSymbol::String_StringBuilder_signature();
419 int_sig = ciSymbol::int_StringBuilder_signature();
420 char_sig = ciSymbol::char_StringBuilder_signature();
421 } else if (m->holder() == C->env()->StringBuffer_klass()) {
422 string_sig = ciSymbol::String_StringBuffer_signature();
423 int_sig = ciSymbol::int_StringBuffer_signature();
424 char_sig = ciSymbol::char_StringBuffer_signature();
425 } else {
426 return NULL;
427 }
428 #ifndef PRODUCT
429 if (PrintOptimizeStringConcat) {
430 tty->print("considering toString call in ");
431 call->jvms()->dump_spec(tty); tty->cr();
432 }
433 #endif
434
435 StringConcat* sc = new StringConcat(this, call);
436
437 AllocateNode* alloc = NULL;
438 InitializeNode* init = NULL;
439
440 // possible opportunity for StringBuilder fusion
441 CallStaticJavaNode* cnode = call;
442 while (cnode) {
443 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
444 if (recv->is_Proj()) {
445 recv = recv->in(0);
446 }
447 cnode = recv->isa_CallStaticJava();
448 if (cnode == NULL) {
449 alloc = recv->isa_Allocate();
450 if (alloc == NULL) {
451 break;
452 }
453 // Find the constructor call
454 Node* result = alloc->result_cast();
455 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
456 // strange looking allocation
457 #ifndef PRODUCT
458 if (PrintOptimizeStringConcat) {
459 tty->print("giving up because allocation looks strange ");
460 alloc->jvms()->dump_spec(tty); tty->cr();
461 }
462 #endif
463 break;
464 }
465 Node* constructor = NULL;
466 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
467 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
468 if (use != NULL &&
469 use->method() != NULL &&
470 !use->method()->is_static() &&
471 use->method()->name() == ciSymbol::object_initializer_name() &&
472 use->method()->holder() == m->holder()) {
473 // Matched the constructor.
474 ciSymbol* sig = use->method()->signature()->as_symbol();
475 if (sig == ciSymbol::void_method_signature() ||
476 sig == ciSymbol::int_void_signature() ||
477 sig == ciSymbol::string_void_signature()) {
478 if (sig == ciSymbol::string_void_signature()) {
479 // StringBuilder(String) so pick this up as the first argument
480 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
481 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
482 if (type == TypePtr::NULL_PTR) {
483 // StringBuilder(null) throws exception.
484 #ifndef PRODUCT
485 if (PrintOptimizeStringConcat) {
486 tty->print("giving up because StringBuilder(null) throws exception");
487 alloc->jvms()->dump_spec(tty); tty->cr();
488 }
489 #endif
490 return NULL;
491 }
492 // StringBuilder(str) argument needs null check.
493 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
494 }
495 // The int variant takes an initial size for the backing
496 // array so just treat it like the void version.
497 constructor = use;
498 } else {
499 #ifndef PRODUCT
500 if (PrintOptimizeStringConcat) {
501 tty->print("unexpected constructor signature: %s", sig->as_utf8());
502 }
503 #endif
504 }
505 break;
506 }
507 }
508 if (constructor == NULL) {
509 // couldn't find constructor
510 #ifndef PRODUCT
511 if (PrintOptimizeStringConcat) {
512 tty->print("giving up because couldn't find constructor ");
513 alloc->jvms()->dump_spec(tty); tty->cr();
514 }
515 #endif
516 break;
517 }
518
519 // Walked all the way back and found the constructor call so see
520 // if this call converted into a direct string concatenation.
521 sc->add_control(call);
522 sc->add_control(constructor);
523 sc->add_control(alloc);
524 sc->set_allocation(alloc);
525 sc->add_constructor(constructor);
526 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
527 return sc;
528 } else {
529 return NULL;
530 }
531 } else if (cnode->method() == NULL) {
532 break;
533 } else if (!cnode->method()->is_static() &&
534 cnode->method()->holder() == m->holder() &&
535 cnode->method()->name() == ciSymbol::append_name() &&
536 (cnode->method()->signature()->as_symbol() == string_sig ||
537 cnode->method()->signature()->as_symbol() == char_sig ||
538 cnode->method()->signature()->as_symbol() == int_sig)) {
539 sc->add_control(cnode);
540 Node* arg = cnode->in(TypeFunc::Parms + 1);
541 if (cnode->method()->signature()->as_symbol() == int_sig) {
542 sc->push_int(arg);
543 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
544 sc->push_char(arg);
545 } else {
546 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
547 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
548 if (csj->method() != NULL &&
549 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
550 arg->outcnt() == 1) {
551 // _control is the list of StringBuilder calls nodes which
552 // will be replaced by new String code after this optimization.
553 // Integer::toString() call is not part of StringBuilder calls
554 // chain. It could be eliminated only if its result is used
555 // only by this SB calls chain.
556 // Another limitation: it should be used only once because
557 // it is unknown that it is used only by this SB calls chain
558 // until all related SB calls nodes are collected.
559 assert(arg->unique_out() == cnode, "sanity");
560 sc->add_control(csj);
561 sc->push_int(csj->in(TypeFunc::Parms));
562 continue;
563 }
564 }
565 sc->push_string(arg);
566 }
567 continue;
568 } else {
569 // some unhandled signature
570 #ifndef PRODUCT
571 if (PrintOptimizeStringConcat) {
572 tty->print("giving up because encountered unexpected signature ");
573 cnode->tf()->dump(); tty->cr();
574 cnode->in(TypeFunc::Parms + 1)->dump();
575 }
576 #endif
577 break;
578 }
579 }
580 return NULL;
581 }
582
583
584 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
585 Phase(StringOpts),
586 _gvn(gvn),
587 _visited(Thread::current()->resource_area()) {
588
589 assert(OptimizeStringConcat, "shouldn't be here");
590
591 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
592 ciSymbol::make("[I"), true);
593 if (size_table_field == NULL) {
594 // Something wrong so give up.
595 assert(false, "why can't we find Integer.sizeTable?");
596 return;
597 }
598
599 // Collect the types needed to talk about the various slices of memory
600 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
601
602 // For each locally allocated StringBuffer see if the usages can be
603 // collapsed into a single String construction.
604
605 // Run through the list of allocation looking for SB.toString to see
606 // if it's possible to fuse the usage of the SB into a single String
607 // construction.
608 GrowableArray<StringConcat*> concats;
609 Node_List toStrings = collect_toString_calls();
610 while (toStrings.size() > 0) {
611 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
612 if (sc != NULL) {
613 concats.push(sc);
614 }
615 }
616
617 // try to coalesce separate concats
618 restart:
619 for (int c = 0; c < concats.length(); c++) {
620 StringConcat* sc = concats.at(c);
621 for (int i = 0; i < sc->num_arguments(); i++) {
622 Node* arg = sc->argument_uncast(i);
623 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
624 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
625 for (int o = 0; o < concats.length(); o++) {
626 if (c == o) continue;
627 StringConcat* other = concats.at(o);
628 if (other->end() == csj) {
629 #ifndef PRODUCT
630 if (PrintOptimizeStringConcat) {
631 tty->print_cr("considering stacked concats");
632 }
633 #endif
634
635 StringConcat* merged = sc->merge(other, arg);
636 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
637 #ifndef PRODUCT
638 if (PrintOptimizeStringConcat) {
639 tty->print_cr("stacking would succeed");
640 }
641 #endif
642 if (c < o) {
643 concats.remove_at(o);
644 concats.at_put(c, merged);
645 } else {
646 concats.remove_at(c);
647 concats.at_put(o, merged);
648 }
649 goto restart;
650 } else {
651 #ifndef PRODUCT
652 if (PrintOptimizeStringConcat) {
653 tty->print_cr("stacking would fail");
654 }
655 #endif
656 }
657 }
658 }
659 }
660 }
661 }
662
663
664 for (int c = 0; c < concats.length(); c++) {
665 StringConcat* sc = concats.at(c);
666 replace_string_concat(sc);
667 }
668
669 remove_dead_nodes();
670 }
671
672 void PhaseStringOpts::record_dead_node(Node* dead) {
673 dead_worklist.push(dead);
674 }
675
676 void PhaseStringOpts::remove_dead_nodes() {
677 // Delete any dead nodes to make things clean enough that escape
678 // analysis doesn't get unhappy.
679 while (dead_worklist.size() > 0) {
680 Node* use = dead_worklist.pop();
681 int opc = use->Opcode();
682 switch (opc) {
683 case Op_Region: {
684 uint i = 1;
685 for (i = 1; i < use->req(); i++) {
686 if (use->in(i) != C->top()) {
687 break;
688 }
689 }
690 if (i >= use->req()) {
691 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
692 Node* m = i.get();
693 if (m->is_Phi()) {
694 dead_worklist.push(m);
695 }
696 }
697 C->gvn_replace_by(use, C->top());
698 }
699 break;
700 }
701 case Op_AddP:
702 case Op_CreateEx: {
703 // Recurisvely clean up references to CreateEx so EA doesn't
704 // get unhappy about the partially collapsed graph.
705 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
706 Node* m = i.get();
707 if (m->is_AddP()) {
708 dead_worklist.push(m);
709 }
710 }
711 C->gvn_replace_by(use, C->top());
712 break;
713 }
714 case Op_Phi:
715 if (use->in(0) == C->top()) {
716 C->gvn_replace_by(use, C->top());
717 }
718 break;
719 }
720 }
721 }
722
723
724 bool StringConcat::validate_mem_flow() {
725 Compile* C = _stringopts->C;
726
727 for (uint i = 0; i < _control.size(); i++) {
728 #ifndef PRODUCT
729 Node_List path;
730 #endif
731 Node* curr = _control.at(i);
732 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
733 // Now here's the main invariant in our case:
734 // For memory between the constructor, and appends, and toString we should only see bottom memory,
735 // produced by the previous call we know about.
736 if (!_constructors.contains(curr)) {
737 NOT_PRODUCT(path.push(curr);)
738 Node* mem = curr->in(TypeFunc::Memory);
739 assert(mem != NULL, "calls should have memory edge");
740 assert(!mem->is_Phi(), "should be handled by control flow validation");
741 NOT_PRODUCT(path.push(mem);)
742 while (mem->is_MergeMem()) {
743 for (uint i = 1; i < mem->req(); i++) {
744 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
745 #ifndef PRODUCT
746 if (PrintOptimizeStringConcat) {
747 tty->print("fusion has incorrect memory flow (side effects) for ");
748 _begin->jvms()->dump_spec(tty); tty->cr();
749 path.dump();
750 }
751 #endif
752 return false;
753 }
754 }
755 // skip through a potential MergeMem chain, linked through Bot
756 mem = mem->in(Compile::AliasIdxBot);
757 NOT_PRODUCT(path.push(mem);)
758 }
759 // now let it fall through, and see if we have a projection
760 if (mem->is_Proj()) {
761 // Should point to a previous known call
762 Node *prev = mem->in(0);
763 NOT_PRODUCT(path.push(prev);)
764 if (!prev->is_Call() || !_control.contains(prev)) {
765 #ifndef PRODUCT
766 if (PrintOptimizeStringConcat) {
767 tty->print("fusion has incorrect memory flow (unknown call) for ");
768 _begin->jvms()->dump_spec(tty); tty->cr();
769 path.dump();
770 }
771 #endif
772 return false;
773 }
774 } else {
775 assert(mem->is_Store() || mem->is_LoadStore(), err_msg_res("unexpected node type: %s", mem->Name()));
776 #ifndef PRODUCT
777 if (PrintOptimizeStringConcat) {
778 tty->print("fusion has incorrect memory flow (unexpected source) for ");
779 _begin->jvms()->dump_spec(tty); tty->cr();
780 path.dump();
781 }
782 #endif
783 return false;
784 }
785 } else {
786 // For memory that feeds into constructors it's more complicated.
787 // However the advantage is that any side effect that happens between the Allocate/Initialize and
788 // the constructor will have to be control-dependent on Initialize.
789 // So we actually don't have to do anything, since it's going to be caught by the control flow
790 // analysis.
791 #ifdef ASSERT
792 // Do a quick verification of the control pattern between the constructor and the initialize node
793 assert(curr->is_Call(), "constructor should be a call");
794 // Go up the control starting from the constructor call
795 Node* ctrl = curr->in(0);
796 IfNode* iff = NULL;
797 RegionNode* copy = NULL;
798
799 while (true) {
800 // skip known check patterns
801 if (ctrl->is_Region()) {
802 if (ctrl->as_Region()->is_copy()) {
803 copy = ctrl->as_Region();
804 ctrl = copy->is_copy();
805 } else { // a cast
806 assert(ctrl->req() == 3 &&
807 ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() &&
808 ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() &&
809 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
810 ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(),
811 "must be a simple diamond");
812 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
813 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
814 Node* use = i.get();
815 assert(use == ctrl || use->is_ConstraintCast(),
816 err_msg_res("unexpected user: %s", use->Name()));
817 }
818
819 iff = ctrl->in(1)->in(0)->as_If();
820 ctrl = iff->in(0);
821 }
822 } else if (ctrl->is_IfTrue()) { // null checks, class checks
823 iff = ctrl->in(0)->as_If();
824 assert(iff->is_If(), "must be if");
825 // Verify that the other arm is an uncommon trap
826 Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
827 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
828 assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommond trap");
829 ctrl = iff->in(0);
830 } else {
831 break;
832 }
833 }
834
835 assert(ctrl->is_Proj(), "must be a projection");
836 assert(ctrl->in(0)->is_Initialize(), "should be initialize");
837 for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) {
838 Node* use = i.get();
839 assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(),
840 err_msg_res("unexpected user: %s", use->Name()));
841 }
842 #endif // ASSERT
843 }
844 }
845 }
846
847 #ifndef PRODUCT
848 if (PrintOptimizeStringConcat) {
849 tty->print("fusion has correct memory flow for ");
850 _begin->jvms()->dump_spec(tty); tty->cr();
851 tty->cr();
852 }
853 #endif
854 return true;
855 }
856
857 bool StringConcat::validate_control_flow() {
858 // We found all the calls and arguments now lets see if it's
859 // safe to transform the graph as we would expect.
860
861 // Check to see if this resulted in too many uncommon traps previously
862 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
863 Deoptimization::Reason_intrinsic)) {
864 return false;
865 }
866
867 // Walk backwards over the control flow from toString to the
868 // allocation and make sure all the control flow is ok. This
869 // means it's either going to be eliminated once the calls are
870 // removed or it can safely be transformed into an uncommon
871 // trap.
872
873 int null_check_count = 0;
874 Unique_Node_List ctrl_path;
875
876 assert(_control.contains(_begin), "missing");
877 assert(_control.contains(_end), "missing");
878
879 // Collect the nodes that we know about and will eliminate into ctrl_path
880 for (uint i = 0; i < _control.size(); i++) {
881 // Push the call and it's control projection
882 Node* n = _control.at(i);
883 if (n->is_Allocate()) {
884 AllocateNode* an = n->as_Allocate();
885 InitializeNode* init = an->initialization();
886 ctrl_path.push(init);
887 ctrl_path.push(init->as_Multi()->proj_out(0));
888 }
889 if (n->is_Call()) {
890 CallNode* cn = n->as_Call();
891 ctrl_path.push(cn);
892 ctrl_path.push(cn->proj_out(0));
893 ctrl_path.push(cn->proj_out(0)->unique_out());
894 if (cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0) != NULL) {
895 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
896 }
897 } else {
898 ShouldNotReachHere();
899 }
900 }
901
902 // Skip backwards through the control checking for unexpected control flow
903 Node* ptr = _end;
904 bool fail = false;
905 while (ptr != _begin) {
906 if (ptr->is_Call() && ctrl_path.member(ptr)) {
907 ptr = ptr->in(0);
908 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
909 ptr = ptr->in(0)->in(0)->in(0);
910 assert(ctrl_path.member(ptr), "should be a known piece of control");
911 } else if (ptr->is_IfTrue()) {
912 IfNode* iff = ptr->in(0)->as_If();
913 BoolNode* b = iff->in(1)->isa_Bool();
914
915 if (b == NULL) {
916 fail = true;
917 break;
918 }
919
920 Node* cmp = b->in(1);
921 Node* v1 = cmp->in(1);
922 Node* v2 = cmp->in(2);
923 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
924
925 // Null check of the return of append which can simply be eliminated
926 if (b->_test._test == BoolTest::ne &&
927 v2->bottom_type() == TypePtr::NULL_PTR &&
928 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
929 // NULL check of the return value of the append
930 null_check_count++;
931 if (otherproj->outcnt() == 1) {
932 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
933 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
934 ctrl_path.push(call);
935 }
936 }
937 _control.push(ptr);
938 ptr = ptr->in(0)->in(0);
939 continue;
940 }
941
942 // A test which leads to an uncommon trap which should be safe.
943 // Later this trap will be converted into a trap that restarts
944 // at the beginning.
945 if (otherproj->outcnt() == 1) {
946 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
947 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
948 // control flow leads to uct so should be ok
949 _uncommon_traps.push(call);
950 ctrl_path.push(call);
951 ptr = ptr->in(0)->in(0);
952 continue;
953 }
954 }
955
956 #ifndef PRODUCT
957 // Some unexpected control flow we don't know how to handle.
958 if (PrintOptimizeStringConcat) {
959 tty->print_cr("failing with unknown test");
960 b->dump();
961 cmp->dump();
962 v1->dump();
963 v2->dump();
964 tty->cr();
965 }
966 #endif
967 fail = true;
968 break;
969 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
970 ptr = ptr->in(0)->in(0);
971 } else if (ptr->is_Region()) {
972 Node* copy = ptr->as_Region()->is_copy();
973 if (copy != NULL) {
974 ptr = copy;
975 continue;
976 }
977 if (ptr->req() == 3 &&
978 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
979 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
980 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
981 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
982 // Simple diamond.
983 // XXX should check for possibly merging stores. simple data merges are ok.
984 // The IGVN will make this simple diamond go away when it
985 // transforms the Region. Make sure it sees it.
986 Compile::current()->record_for_igvn(ptr);
987 ptr = ptr->in(1)->in(0)->in(0);
988 continue;
989 }
990 #ifndef PRODUCT
991 if (PrintOptimizeStringConcat) {
992 tty->print_cr("fusion would fail for region");
993 _begin->dump();
994 ptr->dump(2);
995 }
996 #endif
997 fail = true;
998 break;
999 } else {
1000 // other unknown control
1001 if (!fail) {
1002 #ifndef PRODUCT
1003 if (PrintOptimizeStringConcat) {
1004 tty->print_cr("fusion would fail for");
1005 _begin->dump();
1006 }
1007 #endif
1008 fail = true;
1009 }
1010 #ifndef PRODUCT
1011 if (PrintOptimizeStringConcat) {
1012 ptr->dump();
1013 }
1014 #endif
1015 ptr = ptr->in(0);
1016 }
1017 }
1018 #ifndef PRODUCT
1019 if (PrintOptimizeStringConcat && fail) {
1020 tty->cr();
1021 }
1022 #endif
1023 if (fail) return !fail;
1024
1025 // Validate that all these results produced are contained within
1026 // this cluster of objects. First collect all the results produced
1027 // by calls in the region.
1028 _stringopts->_visited.Clear();
1029 Node_List worklist;
1030 Node* final_result = _end->proj_out(TypeFunc::Parms);
1031 for (uint i = 0; i < _control.size(); i++) {
1032 CallNode* cnode = _control.at(i)->isa_Call();
1033 if (cnode != NULL) {
1034 _stringopts->_visited.test_set(cnode->_idx);
1035 }
1036 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
1037 if (result != NULL && result != final_result) {
1038 worklist.push(result);
1039 }
1040 }
1041
1042 Node* last_result = NULL;
1043 while (worklist.size() > 0) {
1044 Node* result = worklist.pop();
1045 if (_stringopts->_visited.test_set(result->_idx))
1046 continue;
1047 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
1048 Node *use = i.get();
1049 if (ctrl_path.member(use)) {
1050 // already checked this
1051 continue;
1052 }
1053 int opc = use->Opcode();
1054 if (opc == Op_CmpP || opc == Op_Node) {
1055 ctrl_path.push(use);
1056 continue;
1057 }
1058 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
1059 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
1060 worklist.push(j.get());
1061 }
1062 worklist.push(use->in(1));
1063 ctrl_path.push(use);
1064 continue;
1065 }
1066 #ifndef PRODUCT
1067 if (PrintOptimizeStringConcat) {
1068 if (result != last_result) {
1069 last_result = result;
1070 tty->print_cr("extra uses for result:");
1071 last_result->dump();
1072 }
1073 use->dump();
1074 }
1075 #endif
1076 fail = true;
1077 break;
1078 }
1079 }
1080
1081 #ifndef PRODUCT
1082 if (PrintOptimizeStringConcat && !fail) {
1083 ttyLocker ttyl;
1084 tty->cr();
1085 tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size());
1086 _begin->jvms()->dump_spec(tty); tty->cr();
1087 for (int i = 0; i < num_arguments(); i++) {
1088 argument(i)->dump();
1089 }
1090 _control.dump();
1091 tty->cr();
1092 }
1093 #endif
1094
1095 return !fail;
1096 }
1097
1098 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
1099 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
1100 Node* klass_node = __ makecon(mirror_type);
1101 BasicType bt = field->layout_type();
1102 ciType* field_klass = field->type();
1103
1104 const Type *type;
1105 if( bt == T_OBJECT ) {
1106 if (!field->type()->is_loaded()) {
1107 type = TypeInstPtr::BOTTOM;
1108 } else if (field->is_constant()) {
1109 // This can happen if the constant oop is non-perm.
1110 ciObject* con = field->constant_value().as_object();
1111 // Do not "join" in the previous type; it doesn't add value,
1112 // and may yield a vacuous result if the field is of interface type.
1113 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
1114 assert(type != NULL, "field singleton type must be consistent");
1115 return __ makecon(type);
1116 } else {
1117 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
1118 }
1119 } else {
1120 type = Type::get_const_basic_type(bt);
1121 }
1122
1123 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
1124 type, T_OBJECT,
1125 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())));
1126 }
1127
1128 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1129 RegionNode *final_merge = new (C) RegionNode(3);
1130 kit.gvn().set_type(final_merge, Type::CONTROL);
1131 Node* final_size = new (C) PhiNode(final_merge, TypeInt::INT);
1132 kit.gvn().set_type(final_size, TypeInt::INT);
1133
1134 IfNode* iff = kit.create_and_map_if(kit.control(),
1135 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1136 PROB_FAIR, COUNT_UNKNOWN);
1137 Node* is_min = __ IfFalse(iff);
1138 final_merge->init_req(1, is_min);
1139 final_size->init_req(1, __ intcon(11));
1140
1141 kit.set_control(__ IfTrue(iff));
1142 if (kit.stopped()) {
1143 final_merge->init_req(2, C->top());
1144 final_size->init_req(2, C->top());
1145 } else {
1146
1147 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1148 RegionNode *r = new (C) RegionNode(3);
1149 kit.gvn().set_type(r, Type::CONTROL);
1150 Node *phi = new (C) PhiNode(r, TypeInt::INT);
1151 kit.gvn().set_type(phi, TypeInt::INT);
1152 Node *size = new (C) PhiNode(r, TypeInt::INT);
1153 kit.gvn().set_type(size, TypeInt::INT);
1154 Node* chk = __ CmpI(arg, __ intcon(0));
1155 Node* p = __ Bool(chk, BoolTest::lt);
1156 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1157 Node* lessthan = __ IfTrue(iff);
1158 Node* greaterequal = __ IfFalse(iff);
1159 r->init_req(1, lessthan);
1160 phi->init_req(1, __ SubI(__ intcon(0), arg));
1161 size->init_req(1, __ intcon(1));
1162 r->init_req(2, greaterequal);
1163 phi->init_req(2, arg);
1164 size->init_req(2, __ intcon(0));
1165 kit.set_control(r);
1166 C->record_for_igvn(r);
1167 C->record_for_igvn(phi);
1168 C->record_for_igvn(size);
1169
1170 // for (int i=0; ; i++)
1171 // if (x <= sizeTable[i])
1172 // return i+1;
1173
1174 // Add loop predicate first.
1175 kit.add_predicate();
1176
1177 RegionNode *loop = new (C) RegionNode(3);
1178 loop->init_req(1, kit.control());
1179 kit.gvn().set_type(loop, Type::CONTROL);
1180
1181 Node *index = new (C) PhiNode(loop, TypeInt::INT);
1182 index->init_req(1, __ intcon(0));
1183 kit.gvn().set_type(index, TypeInt::INT);
1184 kit.set_control(loop);
1185 Node* sizeTable = fetch_static_field(kit, size_table_field);
1186
1187 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1188 C->record_for_igvn(value);
1189 Node* limit = __ CmpI(phi, value);
1190 Node* limitb = __ Bool(limit, BoolTest::le);
1191 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1192 Node* lessEqual = __ IfTrue(iff2);
1193 Node* greater = __ IfFalse(iff2);
1194
1195 loop->init_req(2, greater);
1196 index->init_req(2, __ AddI(index, __ intcon(1)));
1197
1198 kit.set_control(lessEqual);
1199 C->record_for_igvn(loop);
1200 C->record_for_igvn(index);
1201
1202 final_merge->init_req(2, kit.control());
1203 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1204 }
1205
1206 kit.set_control(final_merge);
1207 C->record_for_igvn(final_merge);
1208 C->record_for_igvn(final_size);
1209
1210 return final_size;
1211 }
1212
1213 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1214 RegionNode *final_merge = new (C) RegionNode(4);
1215 kit.gvn().set_type(final_merge, Type::CONTROL);
1216 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1217 kit.gvn().set_type(final_mem, Type::MEMORY);
1218
1219 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1220 {
1221 // i == MIN_VALUE
1222 IfNode* iff = kit.create_and_map_if(kit.control(),
1223 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1224 PROB_FAIR, COUNT_UNKNOWN);
1225
1226 Node* old_mem = kit.memory(char_adr_idx);
1227
1228 kit.set_control(__ IfFalse(iff));
1229 if (kit.stopped()) {
1230 // Statically not equal to MIN_VALUE so this path is dead
1231 final_merge->init_req(3, kit.control());
1232 } else {
1233 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1234 char_array, start);
1235 final_merge->init_req(3, kit.control());
1236 final_mem->init_req(3, kit.memory(char_adr_idx));
1237 }
1238
1239 kit.set_control(__ IfTrue(iff));
1240 kit.set_memory(old_mem, char_adr_idx);
1241 }
1242
1243
1244 // Simplified version of Integer.getChars
1245
1246 // int q, r;
1247 // int charPos = index;
1248 Node* charPos = end;
1249
1250 // char sign = 0;
1251
1252 Node* i = arg;
1253 Node* sign = __ intcon(0);
1254
1255 // if (i < 0) {
1256 // sign = '-';
1257 // i = -i;
1258 // }
1259 {
1260 IfNode* iff = kit.create_and_map_if(kit.control(),
1261 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1262 PROB_FAIR, COUNT_UNKNOWN);
1263
1264 RegionNode *merge = new (C) RegionNode(3);
1265 kit.gvn().set_type(merge, Type::CONTROL);
1266 i = new (C) PhiNode(merge, TypeInt::INT);
1267 kit.gvn().set_type(i, TypeInt::INT);
1268 sign = new (C) PhiNode(merge, TypeInt::INT);
1269 kit.gvn().set_type(sign, TypeInt::INT);
1270
1271 merge->init_req(1, __ IfTrue(iff));
1272 i->init_req(1, __ SubI(__ intcon(0), arg));
1273 sign->init_req(1, __ intcon('-'));
1274 merge->init_req(2, __ IfFalse(iff));
1275 i->init_req(2, arg);
1276 sign->init_req(2, __ intcon(0));
1277
1278 kit.set_control(merge);
1279
1280 C->record_for_igvn(merge);
1281 C->record_for_igvn(i);
1282 C->record_for_igvn(sign);
1283 }
1284
1285 // for (;;) {
1286 // q = i / 10;
1287 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1288 // buf [--charPos] = digits [r];
1289 // i = q;
1290 // if (i == 0) break;
1291 // }
1292
1293 {
1294 // Add loop predicate first.
1295 kit.add_predicate();
1296
1297 RegionNode *head = new (C) RegionNode(3);
1298 head->init_req(1, kit.control());
1299 kit.gvn().set_type(head, Type::CONTROL);
1300 Node *i_phi = new (C) PhiNode(head, TypeInt::INT);
1301 i_phi->init_req(1, i);
1302 kit.gvn().set_type(i_phi, TypeInt::INT);
1303 charPos = PhiNode::make(head, charPos);
1304 kit.gvn().set_type(charPos, TypeInt::INT);
1305 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1306 kit.gvn().set_type(mem, Type::MEMORY);
1307 kit.set_control(head);
1308 kit.set_memory(mem, char_adr_idx);
1309
1310 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1311 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1312 __ LShiftI(q, __ intcon(1))));
1313 Node* m1 = __ SubI(charPos, __ intcon(1));
1314 Node* ch = __ AddI(r, __ intcon('0'));
1315
1316 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1317 ch, T_CHAR, char_adr_idx);
1318
1319
1320 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1321 PROB_FAIR, COUNT_UNKNOWN);
1322 Node* ne = __ IfTrue(iff);
1323 Node* eq = __ IfFalse(iff);
1324
1325 head->init_req(2, ne);
1326 mem->init_req(2, st);
1327 i_phi->init_req(2, q);
1328 charPos->init_req(2, m1);
1329
1330 charPos = m1;
1331
1332 kit.set_control(eq);
1333 kit.set_memory(st, char_adr_idx);
1334
1335 C->record_for_igvn(head);
1336 C->record_for_igvn(mem);
1337 C->record_for_igvn(i_phi);
1338 C->record_for_igvn(charPos);
1339 }
1340
1341 {
1342 // if (sign != 0) {
1343 // buf [--charPos] = sign;
1344 // }
1345 IfNode* iff = kit.create_and_map_if(kit.control(),
1346 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1347 PROB_FAIR, COUNT_UNKNOWN);
1348
1349 final_merge->init_req(2, __ IfFalse(iff));
1350 final_mem->init_req(2, kit.memory(char_adr_idx));
1351
1352 kit.set_control(__ IfTrue(iff));
1353 if (kit.stopped()) {
1354 final_merge->init_req(1, C->top());
1355 final_mem->init_req(1, C->top());
1356 } else {
1357 Node* m1 = __ SubI(charPos, __ intcon(1));
1358 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1359 sign, T_CHAR, char_adr_idx);
1360
1361 final_merge->init_req(1, kit.control());
1362 final_mem->init_req(1, st);
1363 }
1364
1365 kit.set_control(final_merge);
1366 kit.set_memory(final_mem, char_adr_idx);
1367
1368 C->record_for_igvn(final_merge);
1369 C->record_for_igvn(final_mem);
1370 }
1371 }
1372
1373
1374 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1375 Node* string = str;
1376 Node* offset = kit.load_String_offset(kit.control(), string);
1377 Node* count = kit.load_String_length(kit.control(), string);
1378 Node* value = kit.load_String_value (kit.control(), string);
1379
1380 // copy the contents
1381 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1382 // For small constant strings just emit individual stores.
1383 // A length of 6 seems like a good space/speed tradeof.
1384 int c = count->get_int();
1385 int o = offset->get_int();
1386 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1387 ciTypeArray* value_array = t->const_oop()->as_type_array();
1388 for (int e = 0; e < c; e++) {
1389 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1390 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1391 start = __ AddI(start, __ intcon(1));
1392 }
1393 } else {
1394 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1395 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1396 Node* c = count;
1397 Node* extra = NULL;
1398 #ifdef _LP64
1399 c = __ ConvI2L(c);
1400 extra = C->top();
1401 #endif
1402 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1403 OptoRuntime::fast_arraycopy_Type(),
1404 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1405 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1406 src_ptr, dst_ptr, c, extra);
1407 start = __ AddI(start, count);
1408 }
1409 return start;
1410 }
1411
1412
1413 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1414 // Log a little info about the transformation
1415 sc->maybe_log_transform();
1416
1417 // pull the JVMState of the allocation into a SafePointNode to serve as
1418 // as a shim for the insertion of the new code.
1419 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1420 uint size = sc->begin()->req();
1421 SafePointNode* map = new (C) SafePointNode(size, jvms);
1422
1423 // copy the control and memory state from the final call into our
1424 // new starting state. This allows any preceeding tests to feed
1425 // into the new section of code.
1426 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1427 map->init_req(i1, sc->end()->in(i1));
1428 }
1429 // blow away old allocation arguments
1430 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1431 map->init_req(i1, C->top());
1432 }
1433 // Copy the rest of the inputs for the JVMState
1434 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1435 map->init_req(i1, sc->begin()->in(i1));
1436 }
1437 // Make sure the memory state is a MergeMem for parsing.
1438 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1439 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1440 }
1441
1442 jvms->set_map(map);
1443 map->ensure_stack(jvms, jvms->method()->max_stack());
1444
1445
1446 // disconnect all the old StringBuilder calls from the graph
1447 sc->eliminate_unneeded_control();
1448
1449 // At this point all the old work has been completely removed from
1450 // the graph and the saved JVMState exists at the point where the
1451 // final toString call used to be.
1452 GraphKit kit(jvms);
1453
1454 // There may be uncommon traps which are still using the
1455 // intermediate states and these need to be rewritten to point at
1456 // the JVMState at the beginning of the transformation.
1457 sc->convert_uncommon_traps(kit, jvms);
1458
1459 // Now insert the logic to compute the size of the string followed
1460 // by all the logic to construct array and resulting string.
1461
1462 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1463
1464 // Create a region for the overflow checks to merge into.
1465 int args = MAX2(sc->num_arguments(), 1);
1466 RegionNode* overflow = new (C) RegionNode(args);
1467 kit.gvn().set_type(overflow, Type::CONTROL);
1468
1469 // Create a hook node to hold onto the individual sizes since they
1470 // are need for the copying phase.
1471 Node* string_sizes = new (C) Node(args);
1472
1473 Node* length = __ intcon(0);
1474 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1475 Node* arg = sc->argument(argi);
1476 switch (sc->mode(argi)) {
1477 case StringConcat::IntMode: {
1478 Node* string_size = int_stringSize(kit, arg);
1479
1480 // accumulate total
1481 length = __ AddI(length, string_size);
1482
1483 // Cache this value for the use by int_toString
1484 string_sizes->init_req(argi, string_size);
1485 break;
1486 }
1487 case StringConcat::StringNullCheckMode: {
1488 const Type* type = kit.gvn().type(arg);
1489 assert(type != TypePtr::NULL_PTR, "missing check");
1490 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1491 // Null check with uncommont trap since
1492 // StringBuilder(null) throws exception.
1493 // Use special uncommon trap instead of
1494 // calling normal do_null_check().
1495 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1496 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1497 overflow->add_req(__ IfFalse(iff));
1498 Node* notnull = __ IfTrue(iff);
1499 kit.set_control(notnull); // set control for the cast_not_null
1500 arg = kit.cast_not_null(arg, false);
1501 sc->set_argument(argi, arg);
1502 }
1503 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1504 // Fallthrough to add string length.
1505 }
1506 case StringConcat::StringMode: {
1507 const Type* type = kit.gvn().type(arg);
1508 if (type == TypePtr::NULL_PTR) {
1509 // replace the argument with the null checked version
1510 arg = null_string;
1511 sc->set_argument(argi, arg);
1512 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1513 // s = s != null ? s : "null";
1514 // length = length + (s.count - s.offset);
1515 RegionNode *r = new (C) RegionNode(3);
1516 kit.gvn().set_type(r, Type::CONTROL);
1517 Node *phi = new (C) PhiNode(r, type);
1518 kit.gvn().set_type(phi, phi->bottom_type());
1519 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1520 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1521 Node* notnull = __ IfTrue(iff);
1522 Node* isnull = __ IfFalse(iff);
1523 kit.set_control(notnull); // set control for the cast_not_null
1524 r->init_req(1, notnull);
1525 phi->init_req(1, kit.cast_not_null(arg, false));
1526 r->init_req(2, isnull);
1527 phi->init_req(2, null_string);
1528 kit.set_control(r);
1529 C->record_for_igvn(r);
1530 C->record_for_igvn(phi);
1531 // replace the argument with the null checked version
1532 arg = phi;
1533 sc->set_argument(argi, arg);
1534 }
1535
1536 Node* count = kit.load_String_length(kit.control(), arg);
1537
1538 length = __ AddI(length, count);
1539 string_sizes->init_req(argi, NULL);
1540 break;
1541 }
1542 case StringConcat::CharMode: {
1543 // one character only
1544 length = __ AddI(length, __ intcon(1));
1545 break;
1546 }
1547 default:
1548 ShouldNotReachHere();
1549 }
1550 if (argi > 0) {
1551 // Check that the sum hasn't overflowed
1552 IfNode* iff = kit.create_and_map_if(kit.control(),
1553 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1554 PROB_MIN, COUNT_UNKNOWN);
1555 kit.set_control(__ IfFalse(iff));
1556 overflow->set_req(argi, __ IfTrue(iff));
1557 }
1558 }
1559
1560 {
1561 // Hook
1562 PreserveJVMState pjvms(&kit);
1563 kit.set_control(overflow);
1564 C->record_for_igvn(overflow);
1565 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1566 Deoptimization::Action_make_not_entrant);
1567 }
1568
1569 Node* result;
1570 if (!kit.stopped()) {
1571
1572 // length now contains the number of characters needed for the
1573 // char[] so create a new AllocateArray for the char[]
1574 Node* char_array = NULL;
1575 {
1576 PreserveReexecuteState preexecs(&kit);
1577 // The original jvms is for an allocation of either a String or
1578 // StringBuffer so no stack adjustment is necessary for proper
1579 // reexecution. If we deoptimize in the slow path the bytecode
1580 // will be reexecuted and the char[] allocation will be thrown away.
1581 kit.jvms()->set_should_reexecute(true);
1582 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1583 length, 1);
1584 }
1585
1586 // Mark the allocation so that zeroing is skipped since the code
1587 // below will overwrite the entire array
1588 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1589 char_alloc->maybe_set_complete(_gvn);
1590
1591 // Now copy the string representations into the final char[]
1592 Node* start = __ intcon(0);
1593 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1594 Node* arg = sc->argument(argi);
1595 switch (sc->mode(argi)) {
1596 case StringConcat::IntMode: {
1597 Node* end = __ AddI(start, string_sizes->in(argi));
1598 // getChars words backwards so pass the ending point as well as the start
1599 int_getChars(kit, arg, char_array, start, end);
1600 start = end;
1601 break;
1602 }
1603 case StringConcat::StringNullCheckMode:
1604 case StringConcat::StringMode: {
1605 start = copy_string(kit, arg, char_array, start);
1606 break;
1607 }
1608 case StringConcat::CharMode: {
1609 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1610 arg, T_CHAR, char_adr_idx);
1611 start = __ AddI(start, __ intcon(1));
1612 break;
1613 }
1614 default:
1615 ShouldNotReachHere();
1616 }
1617 }
1618
1619 // If we're not reusing an existing String allocation then allocate one here.
1620 result = sc->string_alloc();
1621 if (result == NULL) {
1622 PreserveReexecuteState preexecs(&kit);
1623 // The original jvms is for an allocation of either a String or
1624 // StringBuffer so no stack adjustment is necessary for proper
1625 // reexecution.
1626 kit.jvms()->set_should_reexecute(true);
1627 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1628 }
1629
1630 // Intialize the string
1631 if (java_lang_String::has_offset_field()) {
1632 kit.store_String_offset(kit.control(), result, __ intcon(0));
1633 kit.store_String_length(kit.control(), result, length);
1634 }
1635 kit.store_String_value(kit.control(), result, char_array);
1636 } else {
1637 result = C->top();
1638 }
1639 // hook up the outgoing control and result
1640 kit.replace_call(sc->end(), result);
1641
1642 // Unhook any hook nodes
1643 string_sizes->disconnect_inputs(NULL, C);
1644 sc->cleanup();
1645 }