1 /*
2 * Copyright (c) 2009, 2015, 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 #include "runtime/sharedRuntime.hpp"
38
39 #define __ kit.
40
41 class StringConcat : public ResourceObj {
42 private:
43 PhaseStringOpts* _stringopts;
44 Node* _string_alloc;
45 AllocateNode* _begin; // The allocation the begins the pattern
46 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
47 // SB.toString or or String.<init>(SB.toString)
48 bool _multiple; // indicates this is a fusion of two or more
49 // separate StringBuilders
50
51 Node* _arguments; // The list of arguments to be concatenated
52 GrowableArray<int> _mode; // into a String along with a mode flag
53 // indicating how to treat the value.
54 Node_List _constructors; // List of constructors (many in case of stacked concat)
55 Node_List _control; // List of control nodes that will be deleted
56 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
57 // to restart at the initial JVMState.
58
59 public:
60 // Mode for converting arguments to Strings
61 enum {
62 StringMode,
63 IntMode,
64 CharMode,
65 StringNullCheckMode
66 };
67
68 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
69 _end(end),
70 _begin(NULL),
71 _multiple(false),
72 _string_alloc(NULL),
73 _stringopts(stringopts) {
74 _arguments = new Node(1);
75 _arguments->del_req(0);
76 }
77
78 bool validate_mem_flow();
79 bool validate_control_flow();
80
81 void merge_add() {
82 #if 0
83 // XXX This is place holder code for reusing an existing String
84 // allocation but the logic for checking the state safety is
85 // probably inadequate at the moment.
86 CallProjections endprojs;
87 sc->end()->extract_projections(&endprojs, false);
88 if (endprojs.resproj != NULL) {
89 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
90 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
91 if (use != NULL && use->method() != NULL &&
92 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
93 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
94 // Found useless new String(sb.toString()) so reuse the newly allocated String
95 // when creating the result instead of allocating a new one.
96 sc->set_string_alloc(use->in(TypeFunc::Parms));
97 sc->set_end(use);
98 }
99 }
100 }
101 #endif
102 }
103
104 StringConcat* merge(StringConcat* other, Node* arg);
105
106 void set_allocation(AllocateNode* alloc) {
107 _begin = alloc;
108 }
109
110 void append(Node* value, int mode) {
111 _arguments->add_req(value);
112 _mode.append(mode);
113 }
114 void push(Node* value, int mode) {
115 _arguments->ins_req(0, value);
116 _mode.insert_before(0, mode);
117 }
118
119 void push_string(Node* value) {
120 push(value, StringMode);
121 }
122 void push_string_null_check(Node* value) {
123 push(value, StringNullCheckMode);
124 }
125 void push_int(Node* value) {
126 push(value, IntMode);
127 }
128 void push_char(Node* value) {
129 push(value, CharMode);
130 }
131
132 static bool is_SB_toString(Node* call) {
133 if (call->is_CallStaticJava()) {
134 CallStaticJavaNode* csj = call->as_CallStaticJava();
135 ciMethod* m = csj->method();
136 if (m != NULL &&
137 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
138 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
139 return true;
140 }
141 }
142 return false;
143 }
144
145 static Node* skip_string_null_check(Node* value) {
146 // Look for a diamond shaped Null check of toString() result
147 // (could be code from String.valueOf()):
148 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
149 if (value->is_Phi()) {
150 int true_path = value->as_Phi()->is_diamond_phi();
151 if (true_path != 0) {
152 // phi->region->if_proj->ifnode->bool
153 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
154 Node* cmp = b->in(1);
155 Node* v1 = cmp->in(1);
156 Node* v2 = cmp->in(2);
157 // Null check of the return of toString which can simply be skipped.
158 if (b->_test._test == BoolTest::ne &&
159 v2->bottom_type() == TypePtr::NULL_PTR &&
160 value->in(true_path)->Opcode() == Op_CastPP &&
161 value->in(true_path)->in(1) == v1 &&
162 v1->is_Proj() && is_SB_toString(v1->in(0))) {
163 return v1;
164 }
165 }
166 }
167 return value;
168 }
169
170 Node* argument(int i) {
171 return _arguments->in(i);
172 }
173 Node* argument_uncast(int i) {
174 Node* arg = argument(i);
175 int amode = mode(i);
176 if (amode == StringConcat::StringMode ||
177 amode == StringConcat::StringNullCheckMode) {
178 arg = skip_string_null_check(arg);
179 }
180 return arg;
181 }
182 void set_argument(int i, Node* value) {
183 _arguments->set_req(i, value);
184 }
185 int num_arguments() {
186 return _mode.length();
187 }
188 int mode(int i) {
189 return _mode.at(i);
190 }
191 void add_control(Node* ctrl) {
192 assert(!_control.contains(ctrl), "only push once");
193 _control.push(ctrl);
194 }
195 void add_constructor(Node* init) {
196 assert(!_constructors.contains(init), "only push once");
197 _constructors.push(init);
198 }
199 CallStaticJavaNode* end() { return _end; }
200 AllocateNode* begin() { return _begin; }
201 Node* string_alloc() { return _string_alloc; }
202
203 void eliminate_unneeded_control();
204 void eliminate_initialize(InitializeNode* init);
205 void eliminate_call(CallNode* call);
206
207 void maybe_log_transform() {
208 CompileLog* log = _stringopts->C->log();
209 if (log != NULL) {
210 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
211 num_arguments(),
212 _string_alloc != NULL,
213 _multiple);
214 JVMState* p = _begin->jvms();
215 while (p != NULL) {
216 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
217 p = p->caller();
218 }
219 log->tail("replace_string_concat");
220 }
221 }
222
223 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
224 for (uint u = 0; u < _uncommon_traps.size(); u++) {
225 Node* uct = _uncommon_traps.at(u);
226
227 // Build a new call using the jvms state of the allocate
228 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
229 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
230 const TypePtr* no_memory_effects = NULL;
231 Compile* C = _stringopts->C;
232 CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
233 jvms->bci(), no_memory_effects);
234 for (int e = 0; e < TypeFunc::Parms; e++) {
235 call->init_req(e, uct->in(e));
236 }
237 // Set the trap request to record intrinsic failure if this trap
238 // is taken too many times. Ideally we would handle then traps by
239 // doing the original bookkeeping in the MDO so that if it caused
240 // the code to be thrown out we could still recompile and use the
241 // optimization. Failing the uncommon traps doesn't really mean
242 // that the optimization is a bad idea but there's no other way to
243 // do the MDO updates currently.
244 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
245 Deoptimization::Action_make_not_entrant);
246 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
247 kit.add_safepoint_edges(call);
248
249 _stringopts->gvn()->transform(call);
250 C->gvn_replace_by(uct, call);
251 uct->disconnect_inputs(NULL, C);
252 }
253 }
254
255 void cleanup() {
256 // disconnect the hook node
257 _arguments->disconnect_inputs(NULL, _stringopts->C);
258 }
259 };
260
261
262 void StringConcat::eliminate_unneeded_control() {
263 for (uint i = 0; i < _control.size(); i++) {
264 Node* n = _control.at(i);
265 if (n->is_Allocate()) {
266 eliminate_initialize(n->as_Allocate()->initialization());
267 }
268 if (n->is_Call()) {
269 if (n != _end) {
270 eliminate_call(n->as_Call());
271 }
272 } else if (n->is_IfTrue()) {
273 Compile* C = _stringopts->C;
274 C->gvn_replace_by(n, n->in(0)->in(0));
275 // get rid of the other projection
276 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
277 }
278 }
279 }
280
281
282 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
283 StringConcat* result = new StringConcat(_stringopts, _end);
284 for (uint x = 0; x < _control.size(); x++) {
285 Node* n = _control.at(x);
286 if (n->is_Call()) {
287 result->_control.push(n);
288 }
289 }
290 for (uint x = 0; x < other->_control.size(); x++) {
291 Node* n = other->_control.at(x);
292 if (n->is_Call()) {
293 result->_control.push(n);
294 }
295 }
296 assert(result->_control.contains(other->_end), "what?");
297 assert(result->_control.contains(_begin), "what?");
298 for (int x = 0; x < num_arguments(); x++) {
299 Node* argx = argument_uncast(x);
300 if (argx == arg) {
301 // replace the toString result with the all the arguments that
302 // made up the other StringConcat
303 for (int y = 0; y < other->num_arguments(); y++) {
304 result->append(other->argument(y), other->mode(y));
305 }
306 } else {
307 result->append(argx, mode(x));
308 }
309 }
310 result->set_allocation(other->_begin);
311 for (uint i = 0; i < _constructors.size(); i++) {
312 result->add_constructor(_constructors.at(i));
313 }
314 for (uint i = 0; i < other->_constructors.size(); i++) {
315 result->add_constructor(other->_constructors.at(i));
316 }
317 result->_multiple = true;
318 return result;
319 }
320
321
322 void StringConcat::eliminate_call(CallNode* call) {
323 Compile* C = _stringopts->C;
324 CallProjections projs;
325 call->extract_projections(&projs, false);
326 if (projs.fallthrough_catchproj != NULL) {
327 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
328 }
329 if (projs.fallthrough_memproj != NULL) {
330 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
331 }
332 if (projs.catchall_memproj != NULL) {
333 C->gvn_replace_by(projs.catchall_memproj, C->top());
334 }
335 if (projs.fallthrough_ioproj != NULL) {
336 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
337 }
338 if (projs.catchall_ioproj != NULL) {
339 C->gvn_replace_by(projs.catchall_ioproj, C->top());
340 }
341 if (projs.catchall_catchproj != NULL) {
342 // EA can't cope with the partially collapsed graph this
343 // creates so put it on the worklist to be collapsed later.
344 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
345 Node *use = i.get();
346 int opc = use->Opcode();
347 if (opc == Op_CreateEx || opc == Op_Region) {
348 _stringopts->record_dead_node(use);
349 }
350 }
351 C->gvn_replace_by(projs.catchall_catchproj, C->top());
352 }
353 if (projs.resproj != NULL) {
354 C->gvn_replace_by(projs.resproj, C->top());
355 }
356 C->gvn_replace_by(call, C->top());
357 }
358
359 void StringConcat::eliminate_initialize(InitializeNode* init) {
360 Compile* C = _stringopts->C;
361
362 // Eliminate Initialize node.
363 assert(init->outcnt() <= 2, "only a control and memory projection expected");
364 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
365 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
366 if (ctrl_proj != NULL) {
367 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
368 }
369 Node *mem_proj = init->proj_out(TypeFunc::Memory);
370 if (mem_proj != NULL) {
371 Node *mem = init->in(TypeFunc::Memory);
372 C->gvn_replace_by(mem_proj, mem);
373 }
374 C->gvn_replace_by(init, C->top());
375 init->disconnect_inputs(NULL, C);
376 }
377
378 Node_List PhaseStringOpts::collect_toString_calls() {
379 Node_List string_calls;
380 Node_List worklist;
381
382 _visited.Clear();
383
384 // Prime the worklist
385 for (uint i = 1; i < C->root()->len(); i++) {
386 Node* n = C->root()->in(i);
387 if (n != NULL && !_visited.test_set(n->_idx)) {
388 worklist.push(n);
389 }
390 }
391
392 while (worklist.size() > 0) {
393 Node* ctrl = worklist.pop();
394 if (StringConcat::is_SB_toString(ctrl)) {
395 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
396 string_calls.push(csj);
397 }
398 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
399 worklist.push(ctrl->in(0));
400 }
401 if (ctrl->is_Region()) {
402 for (uint i = 1; i < ctrl->len(); i++) {
403 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
404 worklist.push(ctrl->in(i));
405 }
406 }
407 }
408 }
409 return string_calls;
410 }
411
412
413 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
414 ciMethod* m = call->method();
415 ciSymbol* string_sig;
416 ciSymbol* int_sig;
417 ciSymbol* char_sig;
418 if (m->holder() == C->env()->StringBuilder_klass()) {
419 string_sig = ciSymbol::String_StringBuilder_signature();
420 int_sig = ciSymbol::int_StringBuilder_signature();
421 char_sig = ciSymbol::char_StringBuilder_signature();
422 } else if (m->holder() == C->env()->StringBuffer_klass()) {
423 string_sig = ciSymbol::String_StringBuffer_signature();
424 int_sig = ciSymbol::int_StringBuffer_signature();
425 char_sig = ciSymbol::char_StringBuffer_signature();
426 } else {
427 return NULL;
428 }
429 #ifndef PRODUCT
430 if (PrintOptimizeStringConcat) {
431 tty->print("considering toString call in ");
432 call->jvms()->dump_spec(tty); tty->cr();
433 }
434 #endif
435
436 StringConcat* sc = new StringConcat(this, call);
437
438 AllocateNode* alloc = NULL;
439 InitializeNode* init = NULL;
440
441 // possible opportunity for StringBuilder fusion
442 CallStaticJavaNode* cnode = call;
443 while (cnode) {
444 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
445 if (recv->is_Proj()) {
446 recv = recv->in(0);
447 }
448 cnode = recv->isa_CallStaticJava();
449 if (cnode == NULL) {
450 alloc = recv->isa_Allocate();
451 if (alloc == NULL) {
452 break;
453 }
454 // Find the constructor call
455 Node* result = alloc->result_cast();
456 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
457 // strange looking allocation
458 #ifndef PRODUCT
459 if (PrintOptimizeStringConcat) {
460 tty->print("giving up because allocation looks strange ");
461 alloc->jvms()->dump_spec(tty); tty->cr();
462 }
463 #endif
464 break;
465 }
466 Node* constructor = NULL;
467 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
468 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
469 if (use != NULL &&
470 use->method() != NULL &&
471 !use->method()->is_static() &&
472 use->method()->name() == ciSymbol::object_initializer_name() &&
473 use->method()->holder() == m->holder()) {
474 // Matched the constructor.
475 ciSymbol* sig = use->method()->signature()->as_symbol();
476 if (sig == ciSymbol::void_method_signature() ||
477 sig == ciSymbol::int_void_signature() ||
478 sig == ciSymbol::string_void_signature()) {
479 if (sig == ciSymbol::string_void_signature()) {
480 // StringBuilder(String) so pick this up as the first argument
481 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
482 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
483 if (type == TypePtr::NULL_PTR) {
484 // StringBuilder(null) throws exception.
485 #ifndef PRODUCT
486 if (PrintOptimizeStringConcat) {
487 tty->print("giving up because StringBuilder(null) throws exception");
488 alloc->jvms()->dump_spec(tty); tty->cr();
489 }
490 #endif
491 return NULL;
492 }
493 // StringBuilder(str) argument needs null check.
494 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
495 }
496 // The int variant takes an initial size for the backing
497 // array so just treat it like the void version.
498 constructor = use;
499 } else {
500 #ifndef PRODUCT
501 if (PrintOptimizeStringConcat) {
502 tty->print("unexpected constructor signature: %s", sig->as_utf8());
503 }
504 #endif
505 }
506 break;
507 }
508 }
509 if (constructor == NULL) {
510 // couldn't find constructor
511 #ifndef PRODUCT
512 if (PrintOptimizeStringConcat) {
513 tty->print("giving up because couldn't find constructor ");
514 alloc->jvms()->dump_spec(tty); tty->cr();
515 }
516 #endif
517 break;
518 }
519
520 // Walked all the way back and found the constructor call so see
521 // if this call converted into a direct string concatenation.
522 sc->add_control(call);
523 sc->add_control(constructor);
524 sc->add_control(alloc);
525 sc->set_allocation(alloc);
526 sc->add_constructor(constructor);
527 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
528 return sc;
529 } else {
530 return NULL;
531 }
532 } else if (cnode->method() == NULL) {
533 break;
534 } else if (!cnode->method()->is_static() &&
535 cnode->method()->holder() == m->holder() &&
536 cnode->method()->name() == ciSymbol::append_name() &&
537 (cnode->method()->signature()->as_symbol() == string_sig ||
538 cnode->method()->signature()->as_symbol() == char_sig ||
539 cnode->method()->signature()->as_symbol() == int_sig)) {
540 sc->add_control(cnode);
541 Node* arg = cnode->in(TypeFunc::Parms + 1);
542 if (cnode->method()->signature()->as_symbol() == int_sig) {
543 sc->push_int(arg);
544 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
545 sc->push_char(arg);
546 } else {
547 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
548 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
549 if (csj->method() != NULL &&
550 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
551 arg->outcnt() == 1) {
552 // _control is the list of StringBuilder calls nodes which
553 // will be replaced by new String code after this optimization.
554 // Integer::toString() call is not part of StringBuilder calls
555 // chain. It could be eliminated only if its result is used
556 // only by this SB calls chain.
557 // Another limitation: it should be used only once because
558 // it is unknown that it is used only by this SB calls chain
559 // until all related SB calls nodes are collected.
560 assert(arg->unique_out() == cnode, "sanity");
561 sc->add_control(csj);
562 sc->push_int(csj->in(TypeFunc::Parms));
563 continue;
564 }
565 }
566 sc->push_string(arg);
567 }
568 continue;
569 } else {
570 // some unhandled signature
571 #ifndef PRODUCT
572 if (PrintOptimizeStringConcat) {
573 tty->print("giving up because encountered unexpected signature ");
574 cnode->tf()->dump(); tty->cr();
575 cnode->in(TypeFunc::Parms + 1)->dump();
576 }
577 #endif
578 break;
579 }
580 }
581 return NULL;
582 }
583
584
585 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
586 Phase(StringOpts),
587 _gvn(gvn),
588 _visited(Thread::current()->resource_area()) {
589
590 assert(OptimizeStringConcat, "shouldn't be here");
591
592 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
593 ciSymbol::make("[I"), true);
594 if (size_table_field == NULL) {
595 // Something wrong so give up.
596 assert(false, "why can't we find Integer.sizeTable?");
597 return;
598 }
599
600 // Collect the types needed to talk about the various slices of memory
601 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
602
603 // For each locally allocated StringBuffer see if the usages can be
604 // collapsed into a single String construction.
605
606 // Run through the list of allocation looking for SB.toString to see
607 // if it's possible to fuse the usage of the SB into a single String
608 // construction.
609 GrowableArray<StringConcat*> concats;
610 Node_List toStrings = collect_toString_calls();
611 while (toStrings.size() > 0) {
612 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
613 if (sc != NULL) {
614 concats.push(sc);
615 }
616 }
617
618 // try to coalesce separate concats
619 restart:
620 for (int c = 0; c < concats.length(); c++) {
621 StringConcat* sc = concats.at(c);
622 for (int i = 0; i < sc->num_arguments(); i++) {
623 Node* arg = sc->argument_uncast(i);
624 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
625 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
626 for (int o = 0; o < concats.length(); o++) {
627 if (c == o) continue;
628 StringConcat* other = concats.at(o);
629 if (other->end() == csj) {
630 #ifndef PRODUCT
631 if (PrintOptimizeStringConcat) {
632 tty->print_cr("considering stacked concats");
633 }
634 #endif
635
636 StringConcat* merged = sc->merge(other, arg);
637 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
638 #ifndef PRODUCT
639 if (PrintOptimizeStringConcat) {
640 tty->print_cr("stacking would succeed");
641 }
642 #endif
643 if (c < o) {
644 concats.remove_at(o);
645 concats.at_put(c, merged);
646 } else {
647 concats.remove_at(c);
648 concats.at_put(o, merged);
649 }
650 goto restart;
651 } else {
652 #ifndef PRODUCT
653 if (PrintOptimizeStringConcat) {
654 tty->print_cr("stacking would fail");
655 }
656 #endif
657 }
658 }
659 }
660 }
661 }
662 }
663
664
665 for (int c = 0; c < concats.length(); c++) {
666 StringConcat* sc = concats.at(c);
667 replace_string_concat(sc);
668 }
669
670 remove_dead_nodes();
671 }
672
673 void PhaseStringOpts::record_dead_node(Node* dead) {
674 dead_worklist.push(dead);
675 }
676
677 void PhaseStringOpts::remove_dead_nodes() {
678 // Delete any dead nodes to make things clean enough that escape
679 // analysis doesn't get unhappy.
680 while (dead_worklist.size() > 0) {
681 Node* use = dead_worklist.pop();
682 int opc = use->Opcode();
683 switch (opc) {
684 case Op_Region: {
685 uint i = 1;
686 for (i = 1; i < use->req(); i++) {
687 if (use->in(i) != C->top()) {
688 break;
689 }
690 }
691 if (i >= use->req()) {
692 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
693 Node* m = i.get();
694 if (m->is_Phi()) {
695 dead_worklist.push(m);
696 }
697 }
698 C->gvn_replace_by(use, C->top());
699 }
700 break;
701 }
702 case Op_AddP:
703 case Op_CreateEx: {
704 // Recurisvely clean up references to CreateEx so EA doesn't
705 // get unhappy about the partially collapsed graph.
706 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
707 Node* m = i.get();
708 if (m->is_AddP()) {
709 dead_worklist.push(m);
710 }
711 }
712 C->gvn_replace_by(use, C->top());
713 break;
714 }
715 case Op_Phi:
716 if (use->in(0) == C->top()) {
717 C->gvn_replace_by(use, C->top());
718 }
719 break;
720 }
721 }
722 }
723
724
725 bool StringConcat::validate_mem_flow() {
726 Compile* C = _stringopts->C;
727
728 for (uint i = 0; i < _control.size(); i++) {
729 #ifndef PRODUCT
730 Node_List path;
731 #endif
732 Node* curr = _control.at(i);
733 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
734 // Now here's the main invariant in our case:
735 // For memory between the constructor, and appends, and toString we should only see bottom memory,
736 // produced by the previous call we know about.
737 if (!_constructors.contains(curr)) {
738 NOT_PRODUCT(path.push(curr);)
739 Node* mem = curr->in(TypeFunc::Memory);
740 assert(mem != NULL, "calls should have memory edge");
741 assert(!mem->is_Phi(), "should be handled by control flow validation");
742 NOT_PRODUCT(path.push(mem);)
743 while (mem->is_MergeMem()) {
744 for (uint i = 1; i < mem->req(); i++) {
745 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
746 #ifndef PRODUCT
747 if (PrintOptimizeStringConcat) {
748 tty->print("fusion has incorrect memory flow (side effects) for ");
749 _begin->jvms()->dump_spec(tty); tty->cr();
750 path.dump();
751 }
752 #endif
753 return false;
754 }
755 }
756 // skip through a potential MergeMem chain, linked through Bot
757 mem = mem->in(Compile::AliasIdxBot);
758 NOT_PRODUCT(path.push(mem);)
759 }
760 // now let it fall through, and see if we have a projection
761 if (mem->is_Proj()) {
762 // Should point to a previous known call
763 Node *prev = mem->in(0);
764 NOT_PRODUCT(path.push(prev);)
765 if (!prev->is_Call() || !_control.contains(prev)) {
766 #ifndef PRODUCT
767 if (PrintOptimizeStringConcat) {
768 tty->print("fusion has incorrect memory flow (unknown call) for ");
769 _begin->jvms()->dump_spec(tty); tty->cr();
770 path.dump();
771 }
772 #endif
773 return false;
774 }
775 } else {
776 assert(mem->is_Store() || mem->is_LoadStore(), err_msg_res("unexpected node type: %s", mem->Name()));
777 #ifndef PRODUCT
778 if (PrintOptimizeStringConcat) {
779 tty->print("fusion has incorrect memory flow (unexpected source) for ");
780 _begin->jvms()->dump_spec(tty); tty->cr();
781 path.dump();
782 }
783 #endif
784 return false;
785 }
786 } else {
787 // For memory that feeds into constructors it's more complicated.
788 // However the advantage is that any side effect that happens between the Allocate/Initialize and
789 // the constructor will have to be control-dependent on Initialize.
790 // So we actually don't have to do anything, since it's going to be caught by the control flow
791 // analysis.
792 #ifdef ASSERT
793 // Do a quick verification of the control pattern between the constructor and the initialize node
794 assert(curr->is_Call(), "constructor should be a call");
795 // Go up the control starting from the constructor call
796 Node* ctrl = curr->in(0);
797 IfNode* iff = NULL;
798 RegionNode* copy = NULL;
799
800 while (true) {
801 // skip known check patterns
802 if (ctrl->is_Region()) {
803 if (ctrl->as_Region()->is_copy()) {
804 copy = ctrl->as_Region();
805 ctrl = copy->is_copy();
806 } else { // a cast
807 assert(ctrl->req() == 3 &&
808 ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() &&
809 ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() &&
810 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
811 ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(),
812 "must be a simple diamond");
813 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
814 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
815 Node* use = i.get();
816 assert(use == ctrl || use->is_ConstraintCast(),
817 err_msg_res("unexpected user: %s", use->Name()));
818 }
819
820 iff = ctrl->in(1)->in(0)->as_If();
821 ctrl = iff->in(0);
822 }
823 } else if (ctrl->is_IfTrue()) { // null checks, class checks
824 iff = ctrl->in(0)->as_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 uncommon 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 #ifndef PRODUCT
917 if (PrintOptimizeStringConcat) {
918 tty->print_cr("unexpected input to IfNode");
919 iff->in(1)->dump();
920 tty->cr();
921 }
922 #endif
923 fail = true;
924 break;
925 }
926
927 Node* cmp = b->in(1);
928 Node* v1 = cmp->in(1);
929 Node* v2 = cmp->in(2);
930 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
931
932 // Null check of the return of append which can simply be eliminated
933 if (b->_test._test == BoolTest::ne &&
934 v2->bottom_type() == TypePtr::NULL_PTR &&
935 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
936 // NULL check of the return value of the append
937 null_check_count++;
938 if (otherproj->outcnt() == 1) {
939 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
940 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
941 ctrl_path.push(call);
942 }
943 }
944 _control.push(ptr);
945 ptr = ptr->in(0)->in(0);
946 continue;
947 }
948
949 // A test which leads to an uncommon trap which should be safe.
950 // Later this trap will be converted into a trap that restarts
951 // at the beginning.
952 if (otherproj->outcnt() == 1) {
953 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
954 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
955 // control flow leads to uct so should be ok
956 _uncommon_traps.push(call);
957 ctrl_path.push(call);
958 ptr = ptr->in(0)->in(0);
959 continue;
960 }
961 }
962
963 #ifndef PRODUCT
964 // Some unexpected control flow we don't know how to handle.
965 if (PrintOptimizeStringConcat) {
966 tty->print_cr("failing with unknown test");
967 b->dump();
968 cmp->dump();
969 v1->dump();
970 v2->dump();
971 tty->cr();
972 }
973 #endif
974 fail = true;
975 break;
976 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
977 ptr = ptr->in(0)->in(0);
978 } else if (ptr->is_Region()) {
979 Node* copy = ptr->as_Region()->is_copy();
980 if (copy != NULL) {
981 ptr = copy;
982 continue;
983 }
984 if (ptr->req() == 3 &&
985 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
986 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
987 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
988 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
989 // Simple diamond.
990 // XXX should check for possibly merging stores. simple data merges are ok.
991 // The IGVN will make this simple diamond go away when it
992 // transforms the Region. Make sure it sees it.
993 Compile::current()->record_for_igvn(ptr);
994 ptr = ptr->in(1)->in(0)->in(0);
995 continue;
996 }
997 #ifndef PRODUCT
998 if (PrintOptimizeStringConcat) {
999 tty->print_cr("fusion would fail for region");
1000 _begin->dump();
1001 ptr->dump(2);
1002 }
1003 #endif
1004 fail = true;
1005 break;
1006 } else {
1007 // other unknown control
1008 if (!fail) {
1009 #ifndef PRODUCT
1010 if (PrintOptimizeStringConcat) {
1011 tty->print_cr("fusion would fail for");
1012 _begin->dump();
1013 }
1014 #endif
1015 fail = true;
1016 }
1017 #ifndef PRODUCT
1018 if (PrintOptimizeStringConcat) {
1019 ptr->dump();
1020 }
1021 #endif
1022 ptr = ptr->in(0);
1023 }
1024 }
1025 #ifndef PRODUCT
1026 if (PrintOptimizeStringConcat && fail) {
1027 tty->cr();
1028 }
1029 #endif
1030 if (fail) return !fail;
1031
1032 // Validate that all these results produced are contained within
1033 // this cluster of objects. First collect all the results produced
1034 // by calls in the region.
1035 _stringopts->_visited.Clear();
1036 Node_List worklist;
1037 Node* final_result = _end->proj_out(TypeFunc::Parms);
1038 for (uint i = 0; i < _control.size(); i++) {
1039 CallNode* cnode = _control.at(i)->isa_Call();
1040 if (cnode != NULL) {
1041 _stringopts->_visited.test_set(cnode->_idx);
1042 }
1043 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
1044 if (result != NULL && result != final_result) {
1045 worklist.push(result);
1046 }
1047 }
1048
1049 Node* last_result = NULL;
1050 while (worklist.size() > 0) {
1051 Node* result = worklist.pop();
1052 if (_stringopts->_visited.test_set(result->_idx))
1053 continue;
1054 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
1055 Node *use = i.get();
1056 if (ctrl_path.member(use)) {
1057 // already checked this
1058 continue;
1059 }
1060 int opc = use->Opcode();
1061 if (opc == Op_CmpP || opc == Op_Node) {
1062 ctrl_path.push(use);
1063 continue;
1064 }
1065 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
1066 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
1067 worklist.push(j.get());
1068 }
1069 worklist.push(use->in(1));
1070 ctrl_path.push(use);
1071 continue;
1072 }
1073 #ifndef PRODUCT
1074 if (PrintOptimizeStringConcat) {
1075 if (result != last_result) {
1076 last_result = result;
1077 tty->print_cr("extra uses for result:");
1078 last_result->dump();
1079 }
1080 use->dump();
1081 }
1082 #endif
1083 fail = true;
1084 break;
1085 }
1086 }
1087
1088 #ifndef PRODUCT
1089 if (PrintOptimizeStringConcat && !fail) {
1090 ttyLocker ttyl;
1091 tty->cr();
1092 tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size());
1093 _begin->jvms()->dump_spec(tty); tty->cr();
1094 for (int i = 0; i < num_arguments(); i++) {
1095 argument(i)->dump();
1096 }
1097 _control.dump();
1098 tty->cr();
1099 }
1100 #endif
1101
1102 return !fail;
1103 }
1104
1105 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
1106 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
1107 Node* klass_node = __ makecon(mirror_type);
1108 BasicType bt = field->layout_type();
1109 ciType* field_klass = field->type();
1110
1111 const Type *type;
1112 if( bt == T_OBJECT ) {
1113 if (!field->type()->is_loaded()) {
1114 type = TypeInstPtr::BOTTOM;
1115 } else if (field->is_constant()) {
1116 // This can happen if the constant oop is non-perm.
1117 ciObject* con = field->constant_value().as_object();
1118 // Do not "join" in the previous type; it doesn't add value,
1119 // and may yield a vacuous result if the field is of interface type.
1120 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
1121 assert(type != NULL, "field singleton type must be consistent");
1122 return __ makecon(type);
1123 } else {
1124 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
1125 }
1126 } else {
1127 type = Type::get_const_basic_type(bt);
1128 }
1129
1130 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
1131 type, T_OBJECT,
1132 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())),
1133 MemNode::unordered);
1134 }
1135
1136 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1137 RegionNode *final_merge = new RegionNode(3);
1138 kit.gvn().set_type(final_merge, Type::CONTROL);
1139 Node* final_size = new PhiNode(final_merge, TypeInt::INT);
1140 kit.gvn().set_type(final_size, TypeInt::INT);
1141
1142 IfNode* iff = kit.create_and_map_if(kit.control(),
1143 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1144 PROB_FAIR, COUNT_UNKNOWN);
1145 Node* is_min = __ IfFalse(iff);
1146 final_merge->init_req(1, is_min);
1147 final_size->init_req(1, __ intcon(11));
1148
1149 kit.set_control(__ IfTrue(iff));
1150 if (kit.stopped()) {
1151 final_merge->init_req(2, C->top());
1152 final_size->init_req(2, C->top());
1153 } else {
1154
1155 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1156 RegionNode *r = new RegionNode(3);
1157 kit.gvn().set_type(r, Type::CONTROL);
1158 Node *phi = new PhiNode(r, TypeInt::INT);
1159 kit.gvn().set_type(phi, TypeInt::INT);
1160 Node *size = new PhiNode(r, TypeInt::INT);
1161 kit.gvn().set_type(size, TypeInt::INT);
1162 Node* chk = __ CmpI(arg, __ intcon(0));
1163 Node* p = __ Bool(chk, BoolTest::lt);
1164 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1165 Node* lessthan = __ IfTrue(iff);
1166 Node* greaterequal = __ IfFalse(iff);
1167 r->init_req(1, lessthan);
1168 phi->init_req(1, __ SubI(__ intcon(0), arg));
1169 size->init_req(1, __ intcon(1));
1170 r->init_req(2, greaterequal);
1171 phi->init_req(2, arg);
1172 size->init_req(2, __ intcon(0));
1173 kit.set_control(r);
1174 C->record_for_igvn(r);
1175 C->record_for_igvn(phi);
1176 C->record_for_igvn(size);
1177
1178 // for (int i=0; ; i++)
1179 // if (x <= sizeTable[i])
1180 // return i+1;
1181
1182 // Add loop predicate first.
1183 kit.add_predicate();
1184
1185 RegionNode *loop = new RegionNode(3);
1186 loop->init_req(1, kit.control());
1187 kit.gvn().set_type(loop, Type::CONTROL);
1188
1189 Node *index = new PhiNode(loop, TypeInt::INT);
1190 index->init_req(1, __ intcon(0));
1191 kit.gvn().set_type(index, TypeInt::INT);
1192 kit.set_control(loop);
1193 Node* sizeTable = fetch_static_field(kit, size_table_field);
1194
1195 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1196 C->record_for_igvn(value);
1197 Node* limit = __ CmpI(phi, value);
1198 Node* limitb = __ Bool(limit, BoolTest::le);
1199 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1200 Node* lessEqual = __ IfTrue(iff2);
1201 Node* greater = __ IfFalse(iff2);
1202
1203 loop->init_req(2, greater);
1204 index->init_req(2, __ AddI(index, __ intcon(1)));
1205
1206 kit.set_control(lessEqual);
1207 C->record_for_igvn(loop);
1208 C->record_for_igvn(index);
1209
1210 final_merge->init_req(2, kit.control());
1211 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1212 }
1213
1214 kit.set_control(final_merge);
1215 C->record_for_igvn(final_merge);
1216 C->record_for_igvn(final_size);
1217
1218 return final_size;
1219 }
1220
1221 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1222 RegionNode *final_merge = new RegionNode(4);
1223 kit.gvn().set_type(final_merge, Type::CONTROL);
1224 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1225 kit.gvn().set_type(final_mem, Type::MEMORY);
1226
1227 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1228 {
1229 // i == MIN_VALUE
1230 IfNode* iff = kit.create_and_map_if(kit.control(),
1231 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1232 PROB_FAIR, COUNT_UNKNOWN);
1233
1234 Node* old_mem = kit.memory(char_adr_idx);
1235
1236 kit.set_control(__ IfFalse(iff));
1237 if (kit.stopped()) {
1238 // Statically not equal to MIN_VALUE so this path is dead
1239 final_merge->init_req(3, kit.control());
1240 } else {
1241 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1242 char_array, start);
1243 final_merge->init_req(3, kit.control());
1244 final_mem->init_req(3, kit.memory(char_adr_idx));
1245 }
1246
1247 kit.set_control(__ IfTrue(iff));
1248 kit.set_memory(old_mem, char_adr_idx);
1249 }
1250
1251
1252 // Simplified version of Integer.getChars
1253
1254 // int q, r;
1255 // int charPos = index;
1256 Node* charPos = end;
1257
1258 // char sign = 0;
1259
1260 Node* i = arg;
1261 Node* sign = __ intcon(0);
1262
1263 // if (i < 0) {
1264 // sign = '-';
1265 // i = -i;
1266 // }
1267 {
1268 IfNode* iff = kit.create_and_map_if(kit.control(),
1269 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1270 PROB_FAIR, COUNT_UNKNOWN);
1271
1272 RegionNode *merge = new RegionNode(3);
1273 kit.gvn().set_type(merge, Type::CONTROL);
1274 i = new PhiNode(merge, TypeInt::INT);
1275 kit.gvn().set_type(i, TypeInt::INT);
1276 sign = new PhiNode(merge, TypeInt::INT);
1277 kit.gvn().set_type(sign, TypeInt::INT);
1278
1279 merge->init_req(1, __ IfTrue(iff));
1280 i->init_req(1, __ SubI(__ intcon(0), arg));
1281 sign->init_req(1, __ intcon('-'));
1282 merge->init_req(2, __ IfFalse(iff));
1283 i->init_req(2, arg);
1284 sign->init_req(2, __ intcon(0));
1285
1286 kit.set_control(merge);
1287
1288 C->record_for_igvn(merge);
1289 C->record_for_igvn(i);
1290 C->record_for_igvn(sign);
1291 }
1292
1293 // for (;;) {
1294 // q = i / 10;
1295 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1296 // buf [--charPos] = digits [r];
1297 // i = q;
1298 // if (i == 0) break;
1299 // }
1300
1301 {
1302 // Add loop predicate first.
1303 kit.add_predicate();
1304
1305 RegionNode *head = new RegionNode(3);
1306 head->init_req(1, kit.control());
1307 kit.gvn().set_type(head, Type::CONTROL);
1308 Node *i_phi = new PhiNode(head, TypeInt::INT);
1309 i_phi->init_req(1, i);
1310 kit.gvn().set_type(i_phi, TypeInt::INT);
1311 charPos = PhiNode::make(head, charPos);
1312 kit.gvn().set_type(charPos, TypeInt::INT);
1313 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1314 kit.gvn().set_type(mem, Type::MEMORY);
1315 kit.set_control(head);
1316 kit.set_memory(mem, char_adr_idx);
1317
1318 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1319 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1320 __ LShiftI(q, __ intcon(1))));
1321 Node* m1 = __ SubI(charPos, __ intcon(1));
1322 Node* ch = __ AddI(r, __ intcon('0'));
1323
1324 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1325 ch, T_CHAR, char_adr_idx, MemNode::unordered);
1326
1327
1328 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1329 PROB_FAIR, COUNT_UNKNOWN);
1330 Node* ne = __ IfTrue(iff);
1331 Node* eq = __ IfFalse(iff);
1332
1333 head->init_req(2, ne);
1334 mem->init_req(2, st);
1335 i_phi->init_req(2, q);
1336 charPos->init_req(2, m1);
1337
1338 charPos = m1;
1339
1340 kit.set_control(eq);
1341 kit.set_memory(st, char_adr_idx);
1342
1343 C->record_for_igvn(head);
1344 C->record_for_igvn(mem);
1345 C->record_for_igvn(i_phi);
1346 C->record_for_igvn(charPos);
1347 }
1348
1349 {
1350 // if (sign != 0) {
1351 // buf [--charPos] = sign;
1352 // }
1353 IfNode* iff = kit.create_and_map_if(kit.control(),
1354 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1355 PROB_FAIR, COUNT_UNKNOWN);
1356
1357 final_merge->init_req(2, __ IfFalse(iff));
1358 final_mem->init_req(2, kit.memory(char_adr_idx));
1359
1360 kit.set_control(__ IfTrue(iff));
1361 if (kit.stopped()) {
1362 final_merge->init_req(1, C->top());
1363 final_mem->init_req(1, C->top());
1364 } else {
1365 Node* m1 = __ SubI(charPos, __ intcon(1));
1366 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1367 sign, T_CHAR, char_adr_idx, MemNode::unordered);
1368
1369 final_merge->init_req(1, kit.control());
1370 final_mem->init_req(1, st);
1371 }
1372
1373 kit.set_control(final_merge);
1374 kit.set_memory(final_mem, char_adr_idx);
1375
1376 C->record_for_igvn(final_merge);
1377 C->record_for_igvn(final_mem);
1378 }
1379 }
1380
1381
1382 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1383 Node* string = str;
1384 Node* offset = kit.load_String_offset(kit.control(), string);
1385 Node* count = kit.load_String_length(kit.control(), string);
1386 Node* value = kit.load_String_value (kit.control(), string);
1387
1388 // copy the contents
1389 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1390 // For small constant strings just emit individual stores.
1391 // A length of 6 seems like a good space/speed tradeof.
1392 int c = count->get_int();
1393 int o = offset->get_int();
1394 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1395 ciTypeArray* value_array = t->const_oop()->as_type_array();
1396 for (int e = 0; e < c; e++) {
1397 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1398 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx,
1399 MemNode::unordered);
1400 start = __ AddI(start, __ intcon(1));
1401 }
1402 } else {
1403 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1404 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1405 Node* c = count;
1406 Node* extra = NULL;
1407 #ifdef _LP64
1408 c = __ ConvI2L(c);
1409 extra = C->top();
1410 #endif
1411 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1412 OptoRuntime::fast_arraycopy_Type(),
1413 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1414 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1415 src_ptr, dst_ptr, c, extra);
1416 start = __ AddI(start, count);
1417 }
1418 return start;
1419 }
1420
1421
1422 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1423 // Log a little info about the transformation
1424 sc->maybe_log_transform();
1425
1426 // pull the JVMState of the allocation into a SafePointNode to serve as
1427 // as a shim for the insertion of the new code.
1428 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1429 uint size = sc->begin()->req();
1430 SafePointNode* map = new SafePointNode(size, jvms);
1431
1432 // copy the control and memory state from the final call into our
1433 // new starting state. This allows any preceeding tests to feed
1434 // into the new section of code.
1435 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1436 map->init_req(i1, sc->end()->in(i1));
1437 }
1438 // blow away old allocation arguments
1439 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1440 map->init_req(i1, C->top());
1441 }
1442 // Copy the rest of the inputs for the JVMState
1443 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1444 map->init_req(i1, sc->begin()->in(i1));
1445 }
1446 // Make sure the memory state is a MergeMem for parsing.
1447 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1448 map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory)));
1449 }
1450
1451 jvms->set_map(map);
1452 map->ensure_stack(jvms, jvms->method()->max_stack());
1453
1454
1455 // disconnect all the old StringBuilder calls from the graph
1456 sc->eliminate_unneeded_control();
1457
1458 // At this point all the old work has been completely removed from
1459 // the graph and the saved JVMState exists at the point where the
1460 // final toString call used to be.
1461 GraphKit kit(jvms);
1462
1463 // There may be uncommon traps which are still using the
1464 // intermediate states and these need to be rewritten to point at
1465 // the JVMState at the beginning of the transformation.
1466 sc->convert_uncommon_traps(kit, jvms);
1467
1468 // Now insert the logic to compute the size of the string followed
1469 // by all the logic to construct array and resulting string.
1470
1471 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1472
1473 // Create a region for the overflow checks to merge into.
1474 int args = MAX2(sc->num_arguments(), 1);
1475 RegionNode* overflow = new RegionNode(args);
1476 kit.gvn().set_type(overflow, Type::CONTROL);
1477
1478 // Create a hook node to hold onto the individual sizes since they
1479 // are need for the copying phase.
1480 Node* string_sizes = new Node(args);
1481
1482 Node* length = __ intcon(0);
1483 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1484 Node* arg = sc->argument(argi);
1485 switch (sc->mode(argi)) {
1486 case StringConcat::IntMode: {
1487 Node* string_size = int_stringSize(kit, arg);
1488
1489 // accumulate total
1490 length = __ AddI(length, string_size);
1491
1492 // Cache this value for the use by int_toString
1493 string_sizes->init_req(argi, string_size);
1494 break;
1495 }
1496 case StringConcat::StringNullCheckMode: {
1497 const Type* type = kit.gvn().type(arg);
1498 assert(type != TypePtr::NULL_PTR, "missing check");
1499 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1500 // Null check with uncommont trap since
1501 // StringBuilder(null) throws exception.
1502 // Use special uncommon trap instead of
1503 // calling normal do_null_check().
1504 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1505 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1506 overflow->add_req(__ IfFalse(iff));
1507 Node* notnull = __ IfTrue(iff);
1508 kit.set_control(notnull); // set control for the cast_not_null
1509 arg = kit.cast_not_null(arg, false);
1510 sc->set_argument(argi, arg);
1511 }
1512 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1513 // Fallthrough to add string length.
1514 }
1515 case StringConcat::StringMode: {
1516 const Type* type = kit.gvn().type(arg);
1517 Node* count = NULL;
1518 if (type == TypePtr::NULL_PTR) {
1519 // replace the argument with the null checked version
1520 arg = null_string;
1521 sc->set_argument(argi, arg);
1522 count = kit.load_String_length(kit.control(), arg);
1523 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1524 // s = s != null ? s : "null";
1525 // length = length + (s.count - s.offset);
1526 RegionNode *r = new RegionNode(3);
1527 kit.gvn().set_type(r, Type::CONTROL);
1528 Node *phi = new PhiNode(r, type);
1529 kit.gvn().set_type(phi, phi->bottom_type());
1530 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1531 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1532 Node* notnull = __ IfTrue(iff);
1533 Node* isnull = __ IfFalse(iff);
1534 kit.set_control(notnull); // set control for the cast_not_null
1535 r->init_req(1, notnull);
1536 phi->init_req(1, kit.cast_not_null(arg, false));
1537 r->init_req(2, isnull);
1538 phi->init_req(2, null_string);
1539 kit.set_control(r);
1540 C->record_for_igvn(r);
1541 C->record_for_igvn(phi);
1542 // replace the argument with the null checked version
1543 arg = phi;
1544 sc->set_argument(argi, arg);
1545 count = kit.load_String_length(kit.control(), arg);
1546 } else {
1547 // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP
1548 // kit.control might be a different test, that can be hoisted above the actual nullcheck
1549 // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck.
1550 count = kit.load_String_length(NULL, arg);
1551 }
1552 length = __ AddI(length, count);
1553 string_sizes->init_req(argi, NULL);
1554 break;
1555 }
1556 case StringConcat::CharMode: {
1557 // one character only
1558 length = __ AddI(length, __ intcon(1));
1559 break;
1560 }
1561 default:
1562 ShouldNotReachHere();
1563 }
1564 if (argi > 0) {
1565 // Check that the sum hasn't overflowed
1566 IfNode* iff = kit.create_and_map_if(kit.control(),
1567 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1568 PROB_MIN, COUNT_UNKNOWN);
1569 kit.set_control(__ IfFalse(iff));
1570 overflow->set_req(argi, __ IfTrue(iff));
1571 }
1572 }
1573
1574 {
1575 // Hook
1576 PreserveJVMState pjvms(&kit);
1577 kit.set_control(overflow);
1578 C->record_for_igvn(overflow);
1579 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1580 Deoptimization::Action_make_not_entrant);
1581 }
1582
1583 Node* result;
1584 if (!kit.stopped()) {
1585 Node* char_array = NULL;
1586 if (sc->num_arguments() == 1 &&
1587 (sc->mode(0) == StringConcat::StringMode ||
1588 sc->mode(0) == StringConcat::StringNullCheckMode)) {
1589 // Handle the case when there is only a single String argument.
1590 // In this case, we can just pull the value from the String itself.
1591 char_array = kit.load_String_value(kit.control(), sc->argument(0));
1592 } else {
1593 // length now contains the number of characters needed for the
1594 // char[] so create a new AllocateArray for the char[]
1595 {
1596 PreserveReexecuteState preexecs(&kit);
1597 // The original jvms is for an allocation of either a String or
1598 // StringBuffer so no stack adjustment is necessary for proper
1599 // reexecution. If we deoptimize in the slow path the bytecode
1600 // will be reexecuted and the char[] allocation will be thrown away.
1601 kit.jvms()->set_should_reexecute(true);
1602 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1603 length, 1);
1604 }
1605
1606 // Mark the allocation so that zeroing is skipped since the code
1607 // below will overwrite the entire array
1608 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1609 char_alloc->maybe_set_complete(_gvn);
1610
1611 // Now copy the string representations into the final char[]
1612 Node* start = __ intcon(0);
1613 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1614 Node* arg = sc->argument(argi);
1615 switch (sc->mode(argi)) {
1616 case StringConcat::IntMode: {
1617 Node* end = __ AddI(start, string_sizes->in(argi));
1618 // getChars words backwards so pass the ending point as well as the start
1619 int_getChars(kit, arg, char_array, start, end);
1620 start = end;
1621 break;
1622 }
1623 case StringConcat::StringNullCheckMode:
1624 case StringConcat::StringMode: {
1625 start = copy_string(kit, arg, char_array, start);
1626 break;
1627 }
1628 case StringConcat::CharMode: {
1629 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1630 arg, T_CHAR, char_adr_idx, MemNode::unordered);
1631 start = __ AddI(start, __ intcon(1));
1632 break;
1633 }
1634 default:
1635 ShouldNotReachHere();
1636 }
1637 }
1638 }
1639
1640 // If we're not reusing an existing String allocation then allocate one here.
1641 result = sc->string_alloc();
1642 if (result == NULL) {
1643 PreserveReexecuteState preexecs(&kit);
1644 // The original jvms is for an allocation of either a String or
1645 // StringBuffer so no stack adjustment is necessary for proper
1646 // reexecution.
1647 kit.jvms()->set_should_reexecute(true);
1648 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1649 }
1650
1651 // Intialize the string
1652 if (java_lang_String::has_offset_field()) {
1653 kit.store_String_offset(kit.control(), result, __ intcon(0));
1654 kit.store_String_length(kit.control(), result, length);
1655 }
1656 kit.store_String_value(kit.control(), result, char_array);
1657 } else {
1658 result = C->top();
1659 }
1660 // hook up the outgoing control and result
1661 kit.replace_call(sc->end(), result);
1662
1663 // Unhook any hook nodes
1664 string_sizes->disconnect_inputs(NULL, C);
1665 sc->cleanup();
1666 }