1 /*
2 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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 "incls/_precompiled.incl"
26 #include "incls/_stringopts.cpp.incl"
27
28 #define __ kit.
29
30 class StringConcat : public ResourceObj {
31 private:
32 PhaseStringOpts* _stringopts;
33 Node* _string_alloc;
34 AllocateNode* _begin; // The allocation the begins the pattern
35 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
36 // SB.toString or or String.<init>(SB.toString)
37 bool _multiple; // indicates this is a fusion of two or more
38 // separate StringBuilders
39
40 Node* _arguments; // The list of arguments to be concatenated
41 GrowableArray<int> _mode; // into a String along with a mode flag
42 // indicating how to treat the value.
43
44 Node_List _control; // List of control nodes that will be deleted
45 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
46 // to restart at the initial JVMState.
47 public:
48 // Mode for converting arguments to Strings
49 enum {
50 StringMode,
51 IntMode,
52 CharMode
53 };
54
55 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
56 _end(end),
57 _begin(NULL),
58 _multiple(false),
59 _string_alloc(NULL),
60 _stringopts(stringopts) {
61 _arguments = new (_stringopts->C, 1) Node(1);
62 _arguments->del_req(0);
63 }
64
65 bool validate_control_flow();
66
67 void merge_add() {
68 #if 0
69 // XXX This is place holder code for reusing an existing String
70 // allocation but the logic for checking the state safety is
71 // probably inadequate at the moment.
72 CallProjections endprojs;
73 sc->end()->extract_projections(&endprojs, false);
74 if (endprojs.resproj != NULL) {
75 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
76 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
77 if (use != NULL && use->method() != NULL &&
78 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
79 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
80 // Found useless new String(sb.toString()) so reuse the newly allocated String
81 // when creating the result instead of allocating a new one.
82 sc->set_string_alloc(use->in(TypeFunc::Parms));
83 sc->set_end(use);
84 }
85 }
86 }
87 #endif
88 }
89
90 StringConcat* merge(StringConcat* other, Node* arg);
91
92 void set_allocation(AllocateNode* alloc) {
93 _begin = alloc;
94 }
95
96 void append(Node* value, int mode) {
97 _arguments->add_req(value);
98 _mode.append(mode);
99 }
100 void push(Node* value, int mode) {
101 _arguments->ins_req(0, value);
102 _mode.insert_before(0, mode);
103 }
104 void push_string(Node* value) {
105 push(value, StringMode);
106 }
107 void push_int(Node* value) {
108 push(value, IntMode);
109 }
110 void push_char(Node* value) {
111 push(value, CharMode);
112 }
113
114 Node* argument(int i) {
115 return _arguments->in(i);
116 }
117 void set_argument(int i, Node* value) {
118 _arguments->set_req(i, value);
119 }
120 int num_arguments() {
121 return _mode.length();
122 }
123 int mode(int i) {
124 return _mode.at(i);
125 }
126 void add_control(Node* ctrl) {
127 assert(!_control.contains(ctrl), "only push once");
128 _control.push(ctrl);
129 }
130 CallStaticJavaNode* end() { return _end; }
131 AllocateNode* begin() { return _begin; }
132 Node* string_alloc() { return _string_alloc; }
133
134 void eliminate_unneeded_control();
135 void eliminate_initialize(InitializeNode* init);
136 void eliminate_call(CallNode* call);
137
138 void maybe_log_transform() {
139 CompileLog* log = _stringopts->C->log();
140 if (log != NULL) {
141 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
142 num_arguments(),
143 _string_alloc != NULL,
144 _multiple);
145 JVMState* p = _begin->jvms();
146 while (p != NULL) {
147 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
148 p = p->caller();
149 }
150 log->tail("replace_string_concat");
151 }
152 }
153
154 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
155 for (uint u = 0; u < _uncommon_traps.size(); u++) {
156 Node* uct = _uncommon_traps.at(u);
157
158 // Build a new call using the jvms state of the allocate
159 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
160 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
161 int size = call_type->domain()->cnt();
162 const TypePtr* no_memory_effects = NULL;
163 Compile* C = _stringopts->C;
164 CallStaticJavaNode* call = new (C, size) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
165 jvms->bci(), no_memory_effects);
166 for (int e = 0; e < TypeFunc::Parms; e++) {
167 call->init_req(e, uct->in(e));
168 }
169 // Set the trap request to record intrinsic failure if this trap
170 // is taken too many times. Ideally we would handle then traps by
171 // doing the original bookkeeping in the MDO so that if it caused
172 // the code to be thrown out we could still recompile and use the
173 // optimization. Failing the uncommon traps doesn't really mean
174 // that the optimization is a bad idea but there's no other way to
175 // do the MDO updates currently.
176 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
177 Deoptimization::Action_make_not_entrant);
178 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
179 kit.add_safepoint_edges(call);
180
181 _stringopts->gvn()->transform(call);
182 C->gvn_replace_by(uct, call);
183 uct->disconnect_inputs(NULL);
184 }
185 }
186
187 void cleanup() {
188 // disconnect the hook node
189 _arguments->disconnect_inputs(NULL);
190 }
191 };
192
193
194 void StringConcat::eliminate_unneeded_control() {
195 eliminate_initialize(begin()->initialization());
196 for (uint i = 0; i < _control.size(); i++) {
197 Node* n = _control.at(i);
198 if (n->is_Call()) {
199 if (n != _end) {
200 eliminate_call(n->as_Call());
201 }
202 } else if (n->is_IfTrue()) {
203 Compile* C = _stringopts->C;
204 C->gvn_replace_by(n, n->in(0)->in(0));
205 C->gvn_replace_by(n->in(0), C->top());
206 }
207 }
208 }
209
210
211 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
212 StringConcat* result = new StringConcat(_stringopts, _end);
213 for (uint x = 0; x < _control.size(); x++) {
214 Node* n = _control.at(x);
215 if (n->is_Call()) {
216 result->_control.push(n);
217 }
218 }
219 for (uint x = 0; x < other->_control.size(); x++) {
220 Node* n = other->_control.at(x);
221 if (n->is_Call()) {
222 result->_control.push(n);
223 }
224 }
225 assert(result->_control.contains(other->_end), "what?");
226 assert(result->_control.contains(_begin), "what?");
227 for (int x = 0; x < num_arguments(); x++) {
228 if (argument(x) == arg) {
229 // replace the toString result with the all the arguments that
230 // made up the other StringConcat
231 for (int y = 0; y < other->num_arguments(); y++) {
232 result->append(other->argument(y), other->mode(y));
233 }
234 } else {
235 result->append(argument(x), mode(x));
236 }
237 }
238 result->set_allocation(other->_begin);
239 result->_multiple = true;
240 return result;
241 }
242
243
244 void StringConcat::eliminate_call(CallNode* call) {
245 Compile* C = _stringopts->C;
246 CallProjections projs;
247 call->extract_projections(&projs, false);
248 if (projs.fallthrough_catchproj != NULL) {
249 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
250 }
251 if (projs.fallthrough_memproj != NULL) {
252 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
253 }
254 if (projs.catchall_memproj != NULL) {
255 C->gvn_replace_by(projs.catchall_memproj, C->top());
256 }
257 if (projs.fallthrough_ioproj != NULL) {
258 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
259 }
260 if (projs.catchall_ioproj != NULL) {
261 C->gvn_replace_by(projs.catchall_ioproj, C->top());
262 }
263 if (projs.catchall_catchproj != NULL) {
264 // EA can't cope with the partially collapsed graph this
265 // creates so put it on the worklist to be collapsed later.
266 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
267 Node *use = i.get();
268 int opc = use->Opcode();
269 if (opc == Op_CreateEx || opc == Op_Region) {
270 _stringopts->record_dead_node(use);
271 }
272 }
273 C->gvn_replace_by(projs.catchall_catchproj, C->top());
274 }
275 if (projs.resproj != NULL) {
276 C->gvn_replace_by(projs.resproj, C->top());
277 }
278 C->gvn_replace_by(call, C->top());
279 }
280
281 void StringConcat::eliminate_initialize(InitializeNode* init) {
282 Compile* C = _stringopts->C;
283
284 // Eliminate Initialize node.
285 assert(init->outcnt() <= 2, "only a control and memory projection expected");
286 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
287 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
288 if (ctrl_proj != NULL) {
289 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
290 }
291 Node *mem_proj = init->proj_out(TypeFunc::Memory);
292 if (mem_proj != NULL) {
293 Node *mem = init->in(TypeFunc::Memory);
294 C->gvn_replace_by(mem_proj, mem);
295 }
296 C->gvn_replace_by(init, C->top());
297 init->disconnect_inputs(NULL);
298 }
299
300 Node_List PhaseStringOpts::collect_toString_calls() {
301 Node_List string_calls;
302 Node_List worklist;
303
304 _visited.Clear();
305
306 // Prime the worklist
307 for (uint i = 1; i < C->root()->len(); i++) {
308 Node* n = C->root()->in(i);
309 if (n != NULL && !_visited.test_set(n->_idx)) {
310 worklist.push(n);
311 }
312 }
313
314 while (worklist.size() > 0) {
315 Node* ctrl = worklist.pop();
316 if (ctrl->is_CallStaticJava()) {
317 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
318 ciMethod* m = csj->method();
319 if (m != NULL &&
320 (m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString ||
321 m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString)) {
322 string_calls.push(csj);
323 }
324 }
325 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
326 worklist.push(ctrl->in(0));
327 }
328 if (ctrl->is_Region()) {
329 for (uint i = 1; i < ctrl->len(); i++) {
330 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
331 worklist.push(ctrl->in(i));
332 }
333 }
334 }
335 }
336 return string_calls;
337 }
338
339
340 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
341 ciMethod* m = call->method();
342 ciSymbol* string_sig;
343 ciSymbol* int_sig;
344 ciSymbol* char_sig;
345 if (m->holder() == C->env()->StringBuilder_klass()) {
346 string_sig = ciSymbol::String_StringBuilder_signature();
347 int_sig = ciSymbol::int_StringBuilder_signature();
348 char_sig = ciSymbol::char_StringBuilder_signature();
349 } else if (m->holder() == C->env()->StringBuffer_klass()) {
350 string_sig = ciSymbol::String_StringBuffer_signature();
351 int_sig = ciSymbol::int_StringBuffer_signature();
352 char_sig = ciSymbol::char_StringBuffer_signature();
353 } else {
354 return NULL;
355 }
356 #ifndef PRODUCT
357 if (PrintOptimizeStringConcat) {
358 tty->print("considering toString call in ");
359 call->jvms()->dump_spec(tty); tty->cr();
360 }
361 #endif
362
363 StringConcat* sc = new StringConcat(this, call);
364
365 AllocateNode* alloc = NULL;
366 InitializeNode* init = NULL;
367
368 // possible opportunity for StringBuilder fusion
369 CallStaticJavaNode* cnode = call;
370 while (cnode) {
371 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
372 if (recv->is_Proj()) {
373 recv = recv->in(0);
374 }
375 cnode = recv->isa_CallStaticJava();
376 if (cnode == NULL) {
377 alloc = recv->isa_Allocate();
378 if (alloc == NULL) {
379 break;
380 }
381 // Find the constructor call
382 Node* result = alloc->result_cast();
383 if (result == NULL || !result->is_CheckCastPP()) {
384 // strange looking allocation
385 #ifndef PRODUCT
386 if (PrintOptimizeStringConcat) {
387 tty->print("giving up because allocation looks strange ");
388 alloc->jvms()->dump_spec(tty); tty->cr();
389 }
390 #endif
391 break;
392 }
393 Node* constructor = NULL;
394 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
395 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
396 if (use != NULL &&
397 use->method() != NULL &&
398 !use->method()->is_static() &&
399 use->method()->name() == ciSymbol::object_initializer_name() &&
400 use->method()->holder() == m->holder()) {
401 // Matched the constructor.
402 ciSymbol* sig = use->method()->signature()->as_symbol();
403 if (sig == ciSymbol::void_method_signature() ||
404 sig == ciSymbol::int_void_signature() ||
405 sig == ciSymbol::string_void_signature()) {
406 if (sig == ciSymbol::string_void_signature()) {
407 // StringBuilder(String) so pick this up as the first argument
408 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
409 sc->push_string(use->in(TypeFunc::Parms + 1));
410 }
411 // The int variant takes an initial size for the backing
412 // array so just treat it like the void version.
413 constructor = use;
414 } else {
415 #ifndef PRODUCT
416 if (PrintOptimizeStringConcat) {
417 tty->print("unexpected constructor signature: %s", sig->as_utf8());
418 }
419 #endif
420 }
421 break;
422 }
423 }
424 if (constructor == NULL) {
425 // couldn't find constructor
426 #ifndef PRODUCT
427 if (PrintOptimizeStringConcat) {
428 tty->print("giving up because couldn't find constructor ");
429 alloc->jvms()->dump_spec(tty);
430 }
431 #endif
432 break;
433 }
434
435 // Walked all the way back and found the constructor call so see
436 // if this call converted into a direct string concatenation.
437 sc->add_control(call);
438 sc->add_control(constructor);
439 sc->add_control(alloc);
440 sc->set_allocation(alloc);
441 if (sc->validate_control_flow()) {
442 return sc;
443 } else {
444 return NULL;
445 }
446 } else if (cnode->method() == NULL) {
447 break;
448 } else if (!cnode->method()->is_static() &&
449 cnode->method()->holder() == m->holder() &&
450 cnode->method()->name() == ciSymbol::append_name() &&
451 (cnode->method()->signature()->as_symbol() == string_sig ||
452 cnode->method()->signature()->as_symbol() == char_sig ||
453 cnode->method()->signature()->as_symbol() == int_sig)) {
454 sc->add_control(cnode);
455 Node* arg = cnode->in(TypeFunc::Parms + 1);
456 if (cnode->method()->signature()->as_symbol() == int_sig) {
457 sc->push_int(arg);
458 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
459 sc->push_char(arg);
460 } else {
461 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
462 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
463 if (csj->method() != NULL &&
464 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString) {
465 sc->add_control(csj);
466 sc->push_int(csj->in(TypeFunc::Parms));
467 continue;
468 }
469 }
470 sc->push_string(arg);
471 }
472 continue;
473 } else {
474 // some unhandled signature
475 #ifndef PRODUCT
476 if (PrintOptimizeStringConcat) {
477 tty->print("giving up because encountered unexpected signature ");
478 cnode->tf()->dump(); tty->cr();
479 cnode->in(TypeFunc::Parms + 1)->dump();
480 }
481 #endif
482 break;
483 }
484 }
485 return NULL;
486 }
487
488
489 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
490 Phase(StringOpts),
491 _gvn(gvn),
492 _visited(Thread::current()->resource_area()) {
493
494 assert(OptimizeStringConcat, "shouldn't be here");
495
496 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
497 ciSymbol::make("[I"), true);
498 if (size_table_field == NULL) {
499 // Something wrong so give up.
500 assert(false, "why can't we find Integer.sizeTable?");
501 return;
502 }
503
504 // Collect the types needed to talk about the various slices of memory
505 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
506 false, NULL, 0);
507
508 const TypePtr* value_field_type = string_type->add_offset(java_lang_String::value_offset_in_bytes());
509 const TypePtr* offset_field_type = string_type->add_offset(java_lang_String::offset_offset_in_bytes());
510 const TypePtr* count_field_type = string_type->add_offset(java_lang_String::count_offset_in_bytes());
511
512 value_field_idx = C->get_alias_index(value_field_type);
513 count_field_idx = C->get_alias_index(count_field_type);
514 offset_field_idx = C->get_alias_index(offset_field_type);
515 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
516
517 // For each locally allocated StringBuffer see if the usages can be
518 // collapsed into a single String construction.
519
520 // Run through the list of allocation looking for SB.toString to see
521 // if it's possible to fuse the usage of the SB into a single String
522 // construction.
523 GrowableArray<StringConcat*> concats;
524 Node_List toStrings = collect_toString_calls();
525 while (toStrings.size() > 0) {
526 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
527 if (sc != NULL) {
528 concats.push(sc);
529 }
530 }
531
532 // try to coalesce separate concats
533 restart:
534 for (int c = 0; c < concats.length(); c++) {
535 StringConcat* sc = concats.at(c);
536 for (int i = 0; i < sc->num_arguments(); i++) {
537 Node* arg = sc->argument(i);
538 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
539 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
540 if (csj->method() != NULL &&
541 (csj->method()->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
542 csj->method()->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
543 for (int o = 0; o < concats.length(); o++) {
544 if (c == o) continue;
545 StringConcat* other = concats.at(o);
546 if (other->end() == csj) {
547 #ifndef PRODUCT
548 if (PrintOptimizeStringConcat) {
549 tty->print_cr("considering stacked concats");
550 }
551 #endif
552
553 StringConcat* merged = sc->merge(other, arg);
554 if (merged->validate_control_flow()) {
555 #ifndef PRODUCT
556 if (PrintOptimizeStringConcat) {
557 tty->print_cr("stacking would succeed");
558 }
559 #endif
560 if (c < o) {
561 concats.remove_at(o);
562 concats.at_put(c, merged);
563 } else {
564 concats.remove_at(c);
565 concats.at_put(o, merged);
566 }
567 goto restart;
568 } else {
569 #ifndef PRODUCT
570 if (PrintOptimizeStringConcat) {
571 tty->print_cr("stacking would fail");
572 }
573 #endif
574 }
575 }
576 }
577 }
578 }
579 }
580 }
581
582
583 for (int c = 0; c < concats.length(); c++) {
584 StringConcat* sc = concats.at(c);
585 replace_string_concat(sc);
586 }
587
588 remove_dead_nodes();
589 }
590
591 void PhaseStringOpts::record_dead_node(Node* dead) {
592 dead_worklist.push(dead);
593 }
594
595 void PhaseStringOpts::remove_dead_nodes() {
596 // Delete any dead nodes to make things clean enough that escape
597 // analysis doesn't get unhappy.
598 while (dead_worklist.size() > 0) {
599 Node* use = dead_worklist.pop();
600 int opc = use->Opcode();
601 switch (opc) {
602 case Op_Region: {
603 uint i = 1;
604 for (i = 1; i < use->req(); i++) {
605 if (use->in(i) != C->top()) {
606 break;
607 }
608 }
609 if (i >= use->req()) {
610 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
611 Node* m = i.get();
612 if (m->is_Phi()) {
613 dead_worklist.push(m);
614 }
615 }
616 C->gvn_replace_by(use, C->top());
617 }
618 break;
619 }
620 case Op_AddP:
621 case Op_CreateEx: {
622 // Recurisvely clean up references to CreateEx so EA doesn't
623 // get unhappy about the partially collapsed graph.
624 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
625 Node* m = i.get();
626 if (m->is_AddP()) {
627 dead_worklist.push(m);
628 }
629 }
630 C->gvn_replace_by(use, C->top());
631 break;
632 }
633 case Op_Phi:
634 if (use->in(0) == C->top()) {
635 C->gvn_replace_by(use, C->top());
636 }
637 break;
638 }
639 }
640 }
641
642
643 bool StringConcat::validate_control_flow() {
644 // We found all the calls and arguments now lets see if it's
645 // safe to transform the graph as we would expect.
646
647 // Check to see if this resulted in too many uncommon traps previously
648 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
649 Deoptimization::Reason_intrinsic)) {
650 return false;
651 }
652
653 // Walk backwards over the control flow from toString to the
654 // allocation and make sure all the control flow is ok. This
655 // means it's either going to be eliminated once the calls are
656 // removed or it can safely be transformed into an uncommon
657 // trap.
658
659 int null_check_count = 0;
660 Unique_Node_List ctrl_path;
661
662 assert(_control.contains(_begin), "missing");
663 assert(_control.contains(_end), "missing");
664
665 // Collect the nodes that we know about and will eliminate into ctrl_path
666 for (uint i = 0; i < _control.size(); i++) {
667 // Push the call and it's control projection
668 Node* n = _control.at(i);
669 if (n->is_Allocate()) {
670 AllocateNode* an = n->as_Allocate();
671 InitializeNode* init = an->initialization();
672 ctrl_path.push(init);
673 ctrl_path.push(init->as_Multi()->proj_out(0));
674 }
675 if (n->is_Call()) {
676 CallNode* cn = n->as_Call();
677 ctrl_path.push(cn);
678 ctrl_path.push(cn->proj_out(0));
679 ctrl_path.push(cn->proj_out(0)->unique_out());
680 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
681 } else {
682 ShouldNotReachHere();
683 }
684 }
685
686 // Skip backwards through the control checking for unexpected contro flow
687 Node* ptr = _end;
688 bool fail = false;
689 while (ptr != _begin) {
690 if (ptr->is_Call() && ctrl_path.member(ptr)) {
691 ptr = ptr->in(0);
692 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
693 ptr = ptr->in(0)->in(0)->in(0);
694 assert(ctrl_path.member(ptr), "should be a known piece of control");
695 } else if (ptr->is_IfTrue()) {
696 IfNode* iff = ptr->in(0)->as_If();
697 BoolNode* b = iff->in(1)->isa_Bool();
698 Node* cmp = b->in(1);
699 Node* v1 = cmp->in(1);
700 Node* v2 = cmp->in(2);
701 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
702
703 // Null check of the return of append which can simply be eliminated
704 if (b->_test._test == BoolTest::ne &&
705 v2->bottom_type() == TypePtr::NULL_PTR &&
706 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
707 // NULL check of the return value of the append
708 null_check_count++;
709 if (otherproj->outcnt() == 1) {
710 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
711 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
712 ctrl_path.push(call);
713 }
714 }
715 _control.push(ptr);
716 ptr = ptr->in(0)->in(0);
717 continue;
718 }
719
720 // A test which leads to an uncommon trap which should be safe.
721 // Later this trap will be converted into a trap that restarts
722 // at the beginning.
723 if (otherproj->outcnt() == 1) {
724 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
725 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
726 // control flow leads to uct so should be ok
727 _uncommon_traps.push(call);
728 ctrl_path.push(call);
729 ptr = ptr->in(0)->in(0);
730 continue;
731 }
732 }
733
734 #ifndef PRODUCT
735 // Some unexpected control flow we don't know how to handle.
736 if (PrintOptimizeStringConcat) {
737 tty->print_cr("failing with unknown test");
738 b->dump();
739 cmp->dump();
740 v1->dump();
741 v2->dump();
742 tty->cr();
743 }
744 #endif
745 break;
746 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
747 ptr = ptr->in(0)->in(0);
748 } else if (ptr->is_Region()) {
749 Node* copy = ptr->as_Region()->is_copy();
750 if (copy != NULL) {
751 ptr = copy;
752 continue;
753 }
754 if (ptr->req() == 3 &&
755 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
756 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
757 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
758 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
759 // Simple diamond.
760 // XXX should check for possibly merging stores. simple data merges are ok.
761 ptr = ptr->in(1)->in(0)->in(0);
762 continue;
763 }
764 #ifndef PRODUCT
765 if (PrintOptimizeStringConcat) {
766 tty->print_cr("fusion would fail for region");
767 _begin->dump();
768 ptr->dump(2);
769 }
770 #endif
771 fail = true;
772 break;
773 } else {
774 // other unknown control
775 if (!fail) {
776 #ifndef PRODUCT
777 if (PrintOptimizeStringConcat) {
778 tty->print_cr("fusion would fail for");
779 _begin->dump();
780 }
781 #endif
782 fail = true;
783 }
784 #ifndef PRODUCT
785 if (PrintOptimizeStringConcat) {
786 ptr->dump();
787 }
788 #endif
789 ptr = ptr->in(0);
790 }
791 }
792 #ifndef PRODUCT
793 if (PrintOptimizeStringConcat && fail) {
794 tty->cr();
795 }
796 #endif
797 if (fail) return !fail;
798
799 // Validate that all these results produced are contained within
800 // this cluster of objects. First collect all the results produced
801 // by calls in the region.
802 _stringopts->_visited.Clear();
803 Node_List worklist;
804 Node* final_result = _end->proj_out(TypeFunc::Parms);
805 for (uint i = 0; i < _control.size(); i++) {
806 CallNode* cnode = _control.at(i)->isa_Call();
807 if (cnode != NULL) {
808 _stringopts->_visited.test_set(cnode->_idx);
809 }
810 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
811 if (result != NULL && result != final_result) {
812 worklist.push(result);
813 }
814 }
815
816 Node* last_result = NULL;
817 while (worklist.size() > 0) {
818 Node* result = worklist.pop();
819 if (_stringopts->_visited.test_set(result->_idx))
820 continue;
821 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
822 Node *use = i.get();
823 if (ctrl_path.member(use)) {
824 // already checked this
825 continue;
826 }
827 int opc = use->Opcode();
828 if (opc == Op_CmpP || opc == Op_Node) {
829 ctrl_path.push(use);
830 continue;
831 }
832 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
833 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
834 worklist.push(j.get());
835 }
836 worklist.push(use->in(1));
837 ctrl_path.push(use);
838 continue;
839 }
840 #ifndef PRODUCT
841 if (PrintOptimizeStringConcat) {
842 if (result != last_result) {
843 last_result = result;
844 tty->print_cr("extra uses for result:");
845 last_result->dump();
846 }
847 use->dump();
848 }
849 #endif
850 fail = true;
851 break;
852 }
853 }
854
855 #ifndef PRODUCT
856 if (PrintOptimizeStringConcat && !fail) {
857 ttyLocker ttyl;
858 tty->cr();
859 tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
860 _begin->jvms()->dump_spec(tty); tty->cr();
861 for (int i = 0; i < num_arguments(); i++) {
862 argument(i)->dump();
863 }
864 _control.dump();
865 tty->cr();
866 }
867 #endif
868
869 return !fail;
870 }
871
872 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
873 const TypeKlassPtr* klass_type = TypeKlassPtr::make(field->holder());
874 Node* klass_node = __ makecon(klass_type);
875 BasicType bt = field->layout_type();
876 ciType* field_klass = field->type();
877
878 const Type *type;
879 if( bt == T_OBJECT ) {
880 if (!field->type()->is_loaded()) {
881 type = TypeInstPtr::BOTTOM;
882 } else if (field->is_constant()) {
883 // This can happen if the constant oop is non-perm.
884 ciObject* con = field->constant_value().as_object();
885 // Do not "join" in the previous type; it doesn't add value,
886 // and may yield a vacuous result if the field is of interface type.
887 type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
888 assert(type != NULL, "field singleton type must be consistent");
889 } else {
890 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
891 }
892 } else {
893 type = Type::get_const_basic_type(bt);
894 }
895
896 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
897 type, T_OBJECT,
898 C->get_alias_index(klass_type->add_offset(field->offset_in_bytes())));
899 }
900
901 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
902 RegionNode *final_merge = new (C, 3) RegionNode(3);
903 kit.gvn().set_type(final_merge, Type::CONTROL);
904 Node* final_size = new (C, 3) PhiNode(final_merge, TypeInt::INT);
905 kit.gvn().set_type(final_size, TypeInt::INT);
906
907 IfNode* iff = kit.create_and_map_if(kit.control(),
908 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
909 PROB_FAIR, COUNT_UNKNOWN);
910 Node* is_min = __ IfFalse(iff);
911 final_merge->init_req(1, is_min);
912 final_size->init_req(1, __ intcon(11));
913
914 kit.set_control(__ IfTrue(iff));
915 if (kit.stopped()) {
916 final_merge->init_req(2, C->top());
917 final_size->init_req(2, C->top());
918 } else {
919
920 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
921 RegionNode *r = new (C, 3) RegionNode(3);
922 kit.gvn().set_type(r, Type::CONTROL);
923 Node *phi = new (C, 3) PhiNode(r, TypeInt::INT);
924 kit.gvn().set_type(phi, TypeInt::INT);
925 Node *size = new (C, 3) PhiNode(r, TypeInt::INT);
926 kit.gvn().set_type(size, TypeInt::INT);
927 Node* chk = __ CmpI(arg, __ intcon(0));
928 Node* p = __ Bool(chk, BoolTest::lt);
929 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
930 Node* lessthan = __ IfTrue(iff);
931 Node* greaterequal = __ IfFalse(iff);
932 r->init_req(1, lessthan);
933 phi->init_req(1, __ SubI(__ intcon(0), arg));
934 size->init_req(1, __ intcon(1));
935 r->init_req(2, greaterequal);
936 phi->init_req(2, arg);
937 size->init_req(2, __ intcon(0));
938 kit.set_control(r);
939 C->record_for_igvn(r);
940 C->record_for_igvn(phi);
941 C->record_for_igvn(size);
942
943 // for (int i=0; ; i++)
944 // if (x <= sizeTable[i])
945 // return i+1;
946 RegionNode *loop = new (C, 3) RegionNode(3);
947 loop->init_req(1, kit.control());
948 kit.gvn().set_type(loop, Type::CONTROL);
949
950 Node *index = new (C, 3) PhiNode(loop, TypeInt::INT);
951 index->init_req(1, __ intcon(0));
952 kit.gvn().set_type(index, TypeInt::INT);
953 kit.set_control(loop);
954 Node* sizeTable = fetch_static_field(kit, size_table_field);
955
956 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
957 C->record_for_igvn(value);
958 Node* limit = __ CmpI(phi, value);
959 Node* limitb = __ Bool(limit, BoolTest::le);
960 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
961 Node* lessEqual = __ IfTrue(iff2);
962 Node* greater = __ IfFalse(iff2);
963
964 loop->init_req(2, greater);
965 index->init_req(2, __ AddI(index, __ intcon(1)));
966
967 kit.set_control(lessEqual);
968 C->record_for_igvn(loop);
969 C->record_for_igvn(index);
970
971 final_merge->init_req(2, kit.control());
972 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
973 }
974
975 kit.set_control(final_merge);
976 C->record_for_igvn(final_merge);
977 C->record_for_igvn(final_size);
978
979 return final_size;
980 }
981
982 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
983 RegionNode *final_merge = new (C, 4) RegionNode(4);
984 kit.gvn().set_type(final_merge, Type::CONTROL);
985 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
986 kit.gvn().set_type(final_mem, Type::MEMORY);
987
988 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
989 {
990 // i == MIN_VALUE
991 IfNode* iff = kit.create_and_map_if(kit.control(),
992 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
993 PROB_FAIR, COUNT_UNKNOWN);
994
995 Node* old_mem = kit.memory(char_adr_idx);
996
997 kit.set_control(__ IfFalse(iff));
998 if (kit.stopped()) {
999 // Statically not equal to MIN_VALUE so this path is dead
1000 final_merge->init_req(3, kit.control());
1001 } else {
1002 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1003 char_array, start);
1004 final_merge->init_req(3, kit.control());
1005 final_mem->init_req(3, kit.memory(char_adr_idx));
1006 }
1007
1008 kit.set_control(__ IfTrue(iff));
1009 kit.set_memory(old_mem, char_adr_idx);
1010 }
1011
1012
1013 // Simplified version of Integer.getChars
1014
1015 // int q, r;
1016 // int charPos = index;
1017 Node* charPos = end;
1018
1019 // char sign = 0;
1020
1021 Node* i = arg;
1022 Node* sign = __ intcon(0);
1023
1024 // if (i < 0) {
1025 // sign = '-';
1026 // i = -i;
1027 // }
1028 {
1029 IfNode* iff = kit.create_and_map_if(kit.control(),
1030 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1031 PROB_FAIR, COUNT_UNKNOWN);
1032
1033 RegionNode *merge = new (C, 3) RegionNode(3);
1034 kit.gvn().set_type(merge, Type::CONTROL);
1035 i = new (C, 3) PhiNode(merge, TypeInt::INT);
1036 kit.gvn().set_type(i, TypeInt::INT);
1037 sign = new (C, 3) PhiNode(merge, TypeInt::INT);
1038 kit.gvn().set_type(sign, TypeInt::INT);
1039
1040 merge->init_req(1, __ IfTrue(iff));
1041 i->init_req(1, __ SubI(__ intcon(0), arg));
1042 sign->init_req(1, __ intcon('-'));
1043 merge->init_req(2, __ IfFalse(iff));
1044 i->init_req(2, arg);
1045 sign->init_req(2, __ intcon(0));
1046
1047 kit.set_control(merge);
1048
1049 C->record_for_igvn(merge);
1050 C->record_for_igvn(i);
1051 C->record_for_igvn(sign);
1052 }
1053
1054 // for (;;) {
1055 // q = i / 10;
1056 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1057 // buf [--charPos] = digits [r];
1058 // i = q;
1059 // if (i == 0) break;
1060 // }
1061
1062 {
1063 RegionNode *head = new (C, 3) RegionNode(3);
1064 head->init_req(1, kit.control());
1065 kit.gvn().set_type(head, Type::CONTROL);
1066 Node *i_phi = new (C, 3) PhiNode(head, TypeInt::INT);
1067 i_phi->init_req(1, i);
1068 kit.gvn().set_type(i_phi, TypeInt::INT);
1069 charPos = PhiNode::make(head, charPos);
1070 kit.gvn().set_type(charPos, TypeInt::INT);
1071 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1072 kit.gvn().set_type(mem, Type::MEMORY);
1073 kit.set_control(head);
1074 kit.set_memory(mem, char_adr_idx);
1075
1076 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1077 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1078 __ LShiftI(q, __ intcon(1))));
1079 Node* m1 = __ SubI(charPos, __ intcon(1));
1080 Node* ch = __ AddI(r, __ intcon('0'));
1081
1082 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1083 ch, T_CHAR, char_adr_idx);
1084
1085
1086 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1087 PROB_FAIR, COUNT_UNKNOWN);
1088 Node* ne = __ IfTrue(iff);
1089 Node* eq = __ IfFalse(iff);
1090
1091 head->init_req(2, ne);
1092 mem->init_req(2, st);
1093 i_phi->init_req(2, q);
1094 charPos->init_req(2, m1);
1095
1096 charPos = m1;
1097
1098 kit.set_control(eq);
1099 kit.set_memory(st, char_adr_idx);
1100
1101 C->record_for_igvn(head);
1102 C->record_for_igvn(mem);
1103 C->record_for_igvn(i_phi);
1104 C->record_for_igvn(charPos);
1105 }
1106
1107 {
1108 // if (sign != 0) {
1109 // buf [--charPos] = sign;
1110 // }
1111 IfNode* iff = kit.create_and_map_if(kit.control(),
1112 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1113 PROB_FAIR, COUNT_UNKNOWN);
1114
1115 final_merge->init_req(2, __ IfFalse(iff));
1116 final_mem->init_req(2, kit.memory(char_adr_idx));
1117
1118 kit.set_control(__ IfTrue(iff));
1119 if (kit.stopped()) {
1120 final_merge->init_req(1, C->top());
1121 final_mem->init_req(1, C->top());
1122 } else {
1123 Node* m1 = __ SubI(charPos, __ intcon(1));
1124 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1125 sign, T_CHAR, char_adr_idx);
1126
1127 final_merge->init_req(1, kit.control());
1128 final_mem->init_req(1, st);
1129 }
1130
1131 kit.set_control(final_merge);
1132 kit.set_memory(final_mem, char_adr_idx);
1133
1134 C->record_for_igvn(final_merge);
1135 C->record_for_igvn(final_mem);
1136 }
1137 }
1138
1139
1140 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1141 Node* string = str;
1142 Node* offset = kit.make_load(NULL,
1143 kit.basic_plus_adr(string, string, java_lang_String::offset_offset_in_bytes()),
1144 TypeInt::INT, T_INT, offset_field_idx);
1145 Node* count = kit.make_load(NULL,
1146 kit.basic_plus_adr(string, string, java_lang_String::count_offset_in_bytes()),
1147 TypeInt::INT, T_INT, count_field_idx);
1148 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
1149 TypeAry::make(TypeInt::CHAR,TypeInt::POS),
1150 ciTypeArrayKlass::make(T_CHAR), true, 0);
1151 Node* value = kit.make_load(NULL,
1152 kit.basic_plus_adr(string, string, java_lang_String::value_offset_in_bytes()),
1153 value_type, T_OBJECT, value_field_idx);
1154
1155 // copy the contents
1156 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1157 // For small constant strings just emit individual stores.
1158 // A length of 6 seems like a good space/speed tradeof.
1159 int c = count->get_int();
1160 int o = offset->get_int();
1161 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1162 ciTypeArray* value_array = t->const_oop()->as_type_array();
1163 for (int e = 0; e < c; e++) {
1164 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1165 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1166 start = __ AddI(start, __ intcon(1));
1167 }
1168 } else {
1169 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1170 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1171 Node* c = count;
1172 Node* extra = NULL;
1173 #ifdef _LP64
1174 c = __ ConvI2L(c);
1175 extra = C->top();
1176 #endif
1177 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1178 OptoRuntime::fast_arraycopy_Type(),
1179 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1180 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1181 src_ptr, dst_ptr, c, extra);
1182 start = __ AddI(start, count);
1183 }
1184 return start;
1185 }
1186
1187
1188 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1189 // Log a little info about the transformation
1190 sc->maybe_log_transform();
1191
1192 // pull the JVMState of the allocation into a SafePointNode to serve as
1193 // as a shim for the insertion of the new code.
1194 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1195 uint size = sc->begin()->req();
1196 SafePointNode* map = new (C, size) SafePointNode(size, jvms);
1197
1198 // copy the control and memory state from the final call into our
1199 // new starting state. This allows any preceeding tests to feed
1200 // into the new section of code.
1201 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1202 map->init_req(i1, sc->end()->in(i1));
1203 }
1204 // blow away old allocation arguments
1205 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1206 map->init_req(i1, C->top());
1207 }
1208 // Copy the rest of the inputs for the JVMState
1209 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1210 map->init_req(i1, sc->begin()->in(i1));
1211 }
1212 // Make sure the memory state is a MergeMem for parsing.
1213 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1214 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1215 }
1216
1217 jvms->set_map(map);
1218 map->ensure_stack(jvms, jvms->method()->max_stack());
1219
1220
1221 // disconnect all the old StringBuilder calls from the graph
1222 sc->eliminate_unneeded_control();
1223
1224 // At this point all the old work has been completely removed from
1225 // the graph and the saved JVMState exists at the point where the
1226 // final toString call used to be.
1227 GraphKit kit(jvms);
1228
1229 // There may be uncommon traps which are still using the
1230 // intermediate states and these need to be rewritten to point at
1231 // the JVMState at the beginning of the transformation.
1232 sc->convert_uncommon_traps(kit, jvms);
1233
1234 // Now insert the logic to compute the size of the string followed
1235 // by all the logic to construct array and resulting string.
1236
1237 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1238
1239 // Create a region for the overflow checks to merge into.
1240 int args = MAX2(sc->num_arguments(), 1);
1241 RegionNode* overflow = new (C, args) RegionNode(args);
1242 kit.gvn().set_type(overflow, Type::CONTROL);
1243
1244 // Create a hook node to hold onto the individual sizes since they
1245 // are need for the copying phase.
1246 Node* string_sizes = new (C, args) Node(args);
1247
1248 Node* length = __ intcon(0);
1249 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1250 Node* arg = sc->argument(argi);
1251 switch (sc->mode(argi)) {
1252 case StringConcat::IntMode: {
1253 Node* string_size = int_stringSize(kit, arg);
1254
1255 // accumulate total
1256 length = __ AddI(length, string_size);
1257
1258 // Cache this value for the use by int_toString
1259 string_sizes->init_req(argi, string_size);
1260 break;
1261 }
1262 case StringConcat::StringMode: {
1263 const Type* type = kit.gvn().type(arg);
1264 if (type == TypePtr::NULL_PTR) {
1265 // replace the argument with the null checked version
1266 arg = null_string;
1267 sc->set_argument(argi, arg);
1268 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1269 // s = s != null ? s : "null";
1270 // length = length + (s.count - s.offset);
1271 RegionNode *r = new (C, 3) RegionNode(3);
1272 kit.gvn().set_type(r, Type::CONTROL);
1273 Node *phi = new (C, 3) PhiNode(r, type);
1274 kit.gvn().set_type(phi, phi->bottom_type());
1275 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1276 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1277 Node* notnull = __ IfTrue(iff);
1278 Node* isnull = __ IfFalse(iff);
1279 kit.set_control(notnull); // set control for the cast_not_null
1280 r->init_req(1, notnull);
1281 phi->init_req(1, kit.cast_not_null(arg, false));
1282 r->init_req(2, isnull);
1283 phi->init_req(2, null_string);
1284 kit.set_control(r);
1285 C->record_for_igvn(r);
1286 C->record_for_igvn(phi);
1287 // replace the argument with the null checked version
1288 arg = phi;
1289 sc->set_argument(argi, arg);
1290 }
1291 // Node* offset = kit.make_load(NULL, kit.basic_plus_adr(arg, arg, offset_offset),
1292 // TypeInt::INT, T_INT, offset_field_idx);
1293 Node* count = kit.make_load(NULL, kit.basic_plus_adr(arg, arg, java_lang_String::count_offset_in_bytes()),
1294 TypeInt::INT, T_INT, count_field_idx);
1295 length = __ AddI(length, count);
1296 string_sizes->init_req(argi, NULL);
1297 break;
1298 }
1299 case StringConcat::CharMode: {
1300 // one character only
1301 length = __ AddI(length, __ intcon(1));
1302 break;
1303 }
1304 default:
1305 ShouldNotReachHere();
1306 }
1307 if (argi > 0) {
1308 // Check that the sum hasn't overflowed
1309 IfNode* iff = kit.create_and_map_if(kit.control(),
1310 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1311 PROB_MIN, COUNT_UNKNOWN);
1312 kit.set_control(__ IfFalse(iff));
1313 overflow->set_req(argi, __ IfTrue(iff));
1314 }
1315 }
1316
1317 {
1318 // Hook
1319 PreserveJVMState pjvms(&kit);
1320 kit.set_control(overflow);
1321 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1322 Deoptimization::Action_make_not_entrant);
1323 }
1324
1325 // length now contains the number of characters needed for the
1326 // char[] so create a new AllocateArray for the char[]
1327 Node* char_array = NULL;
1328 {
1329 PreserveReexecuteState preexecs(&kit);
1330 // The original jvms is for an allocation of either a String or
1331 // StringBuffer so no stack adjustment is necessary for proper
1332 // reexecution. If we deoptimize in the slow path the bytecode
1333 // will be reexecuted and the char[] allocation will be thrown away.
1334 kit.jvms()->set_should_reexecute(true);
1335 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1336 length, 1);
1337 }
1338
1339 // Mark the allocation so that zeroing is skipped since the code
1340 // below will overwrite the entire array
1341 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1342 char_alloc->maybe_set_complete(_gvn);
1343
1344 // Now copy the string representations into the final char[]
1345 Node* start = __ intcon(0);
1346 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1347 Node* arg = sc->argument(argi);
1348 switch (sc->mode(argi)) {
1349 case StringConcat::IntMode: {
1350 Node* end = __ AddI(start, string_sizes->in(argi));
1351 // getChars words backwards so pass the ending point as well as the start
1352 int_getChars(kit, arg, char_array, start, end);
1353 start = end;
1354 break;
1355 }
1356 case StringConcat::StringMode: {
1357 start = copy_string(kit, arg, char_array, start);
1358 break;
1359 }
1360 case StringConcat::CharMode: {
1361 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1362 arg, T_CHAR, char_adr_idx);
1363 start = __ AddI(start, __ intcon(1));
1364 break;
1365 }
1366 default:
1367 ShouldNotReachHere();
1368 }
1369 }
1370
1371 // If we're not reusing an existing String allocation then allocate one here.
1372 Node* result = sc->string_alloc();
1373 if (result == NULL) {
1374 PreserveReexecuteState preexecs(&kit);
1375 // The original jvms is for an allocation of either a String or
1376 // StringBuffer so no stack adjustment is necessary for proper
1377 // reexecution.
1378 kit.jvms()->set_should_reexecute(true);
1379 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1380 }
1381
1382 // Intialize the string
1383 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::offset_offset_in_bytes()),
1384 __ intcon(0), T_INT, offset_field_idx);
1385 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::count_offset_in_bytes()),
1386 length, T_INT, count_field_idx);
1387 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::value_offset_in_bytes()),
1388 char_array, T_OBJECT, value_field_idx);
1389
1390 // hook up the outgoing control and result
1391 kit.replace_call(sc->end(), result);
1392
1393 // Unhook any hook nodes
1394 string_sizes->disconnect_inputs(NULL);
1395 sc->cleanup();
1396 }