1 /*
2 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "compiler/compileLog.hpp"
27 #include "opto/addnode.hpp"
28 #include "opto/callGenerator.hpp"
29 #include "opto/callnode.hpp"
30 #include "opto/divnode.hpp"
31 #include "opto/graphKit.hpp"
32 #include "opto/idealKit.hpp"
33 #include "opto/rootnode.hpp"
34 #include "opto/runtime.hpp"
35 #include "opto/stringopts.hpp"
36 #include "opto/subnode.hpp"
37
38 #define __ kit.
39
40 class StringConcat : public ResourceObj {
41 private:
42 PhaseStringOpts* _stringopts;
43 Node* _string_alloc;
44 AllocateNode* _begin; // The allocation the begins the pattern
45 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
46 // SB.toString or or String.<init>(SB.toString)
47 bool _multiple; // indicates this is a fusion of two or more
48 // separate StringBuilders
49
50 Node* _arguments; // The list of arguments to be concatenated
51 GrowableArray<int> _mode; // into a String along with a mode flag
52 // indicating how to treat the value.
53
54 Node_List _control; // List of control nodes that will be deleted
55 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
56 // to restart at the initial JVMState.
57 public:
58 // Mode for converting arguments to Strings
59 enum {
60 StringMode,
61 IntMode,
62 CharMode,
63 StringNullCheckMode
64 };
65
66 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
67 _end(end),
68 _begin(NULL),
69 _multiple(false),
70 _string_alloc(NULL),
71 _stringopts(stringopts) {
72 _arguments = new (_stringopts->C) Node(1);
73 _arguments->del_req(0);
74 }
75
76 bool validate_control_flow();
77
78 void merge_add() {
79 #if 0
80 // XXX This is place holder code for reusing an existing String
81 // allocation but the logic for checking the state safety is
82 // probably inadequate at the moment.
83 CallProjections endprojs;
84 sc->end()->extract_projections(&endprojs, false);
85 if (endprojs.resproj != NULL) {
86 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
87 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
88 if (use != NULL && use->method() != NULL &&
89 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
90 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
91 // Found useless new String(sb.toString()) so reuse the newly allocated String
92 // when creating the result instead of allocating a new one.
93 sc->set_string_alloc(use->in(TypeFunc::Parms));
94 sc->set_end(use);
95 }
96 }
97 }
98 #endif
99 }
100
101 StringConcat* merge(StringConcat* other, Node* arg);
102
103 void set_allocation(AllocateNode* alloc) {
104 _begin = alloc;
105 }
106
107 void append(Node* value, int mode) {
108 _arguments->add_req(value);
109 _mode.append(mode);
110 }
111 void push(Node* value, int mode) {
112 _arguments->ins_req(0, value);
113 _mode.insert_before(0, mode);
114 }
115
116 void push_string(Node* value) {
117 push(value, StringMode);
118 }
119 void push_string_null_check(Node* value) {
120 push(value, StringNullCheckMode);
121 }
122 void push_int(Node* value) {
123 push(value, IntMode);
124 }
125 void push_char(Node* value) {
126 push(value, CharMode);
127 }
128
129 static bool is_SB_toString(Node* call) {
130 if (call->is_CallStaticJava()) {
131 CallStaticJavaNode* csj = call->as_CallStaticJava();
132 ciMethod* m = csj->method();
133 if (m != NULL &&
134 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
135 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
136 return true;
137 }
138 }
139 return false;
140 }
141
142 static Node* skip_string_null_check(Node* value) {
143 // Look for a diamond shaped Null check of toString() result
144 // (could be code from String.valueOf()):
145 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
146 if (value->is_Phi()) {
147 int true_path = value->as_Phi()->is_diamond_phi();
148 if (true_path != 0) {
149 // phi->region->if_proj->ifnode->bool
150 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
151 Node* cmp = b->in(1);
152 Node* v1 = cmp->in(1);
153 Node* v2 = cmp->in(2);
154 // Null check of the return of toString which can simply be skipped.
155 if (b->_test._test == BoolTest::ne &&
156 v2->bottom_type() == TypePtr::NULL_PTR &&
157 value->in(true_path)->Opcode() == Op_CastPP &&
158 value->in(true_path)->in(1) == v1 &&
159 v1->is_Proj() && is_SB_toString(v1->in(0))) {
160 return v1;
161 }
162 }
163 }
164 return value;
165 }
166
167 Node* argument(int i) {
168 return _arguments->in(i);
169 }
170 Node* argument_uncast(int i) {
171 Node* arg = argument(i);
172 int amode = mode(i);
173 if (amode == StringConcat::StringMode ||
174 amode == StringConcat::StringNullCheckMode) {
175 arg = skip_string_null_check(arg);
176 }
177 return arg;
178 }
179 void set_argument(int i, Node* value) {
180 _arguments->set_req(i, value);
181 }
182 int num_arguments() {
183 return _mode.length();
184 }
185 int mode(int i) {
186 return _mode.at(i);
187 }
188 void add_control(Node* ctrl) {
189 assert(!_control.contains(ctrl), "only push once");
190 _control.push(ctrl);
191 }
192 CallStaticJavaNode* end() { return _end; }
193 AllocateNode* begin() { return _begin; }
194 Node* string_alloc() { return _string_alloc; }
195
196 void eliminate_unneeded_control();
197 void eliminate_initialize(InitializeNode* init);
198 void eliminate_call(CallNode* call);
199
200 void maybe_log_transform() {
201 CompileLog* log = _stringopts->C->log();
202 if (log != NULL) {
203 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
204 num_arguments(),
205 _string_alloc != NULL,
206 _multiple);
207 JVMState* p = _begin->jvms();
208 while (p != NULL) {
209 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
210 p = p->caller();
211 }
212 log->tail("replace_string_concat");
213 }
214 }
215
216 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
217 for (uint u = 0; u < _uncommon_traps.size(); u++) {
218 Node* uct = _uncommon_traps.at(u);
219
220 // Build a new call using the jvms state of the allocate
221 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
222 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
223 const TypePtr* no_memory_effects = NULL;
224 Compile* C = _stringopts->C;
225 CallStaticJavaNode* call = new (C) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
226 jvms->bci(), no_memory_effects);
227 for (int e = 0; e < TypeFunc::Parms; e++) {
228 call->init_req(e, uct->in(e));
229 }
230 // Set the trap request to record intrinsic failure if this trap
231 // is taken too many times. Ideally we would handle then traps by
232 // doing the original bookkeeping in the MDO so that if it caused
233 // the code to be thrown out we could still recompile and use the
234 // optimization. Failing the uncommon traps doesn't really mean
235 // that the optimization is a bad idea but there's no other way to
236 // do the MDO updates currently.
237 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
238 Deoptimization::Action_make_not_entrant);
239 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
240 kit.add_safepoint_edges(call);
241
242 _stringopts->gvn()->transform(call);
243 C->gvn_replace_by(uct, call);
244 uct->disconnect_inputs(NULL, C);
245 }
246 }
247
248 void cleanup() {
249 // disconnect the hook node
250 _arguments->disconnect_inputs(NULL, _stringopts->C);
251 }
252 };
253
254
255 void StringConcat::eliminate_unneeded_control() {
256 for (uint i = 0; i < _control.size(); i++) {
257 Node* n = _control.at(i);
258 if (n->is_Allocate()) {
259 eliminate_initialize(n->as_Allocate()->initialization());
260 }
261 if (n->is_Call()) {
262 if (n != _end) {
263 eliminate_call(n->as_Call());
264 }
265 } else if (n->is_IfTrue()) {
266 Compile* C = _stringopts->C;
267 C->gvn_replace_by(n, n->in(0)->in(0));
268 C->gvn_replace_by(n->in(0), C->top());
269 }
270 }
271 }
272
273
274 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
275 StringConcat* result = new StringConcat(_stringopts, _end);
276 for (uint x = 0; x < _control.size(); x++) {
277 Node* n = _control.at(x);
278 if (n->is_Call()) {
279 result->_control.push(n);
280 }
281 }
282 for (uint x = 0; x < other->_control.size(); x++) {
283 Node* n = other->_control.at(x);
284 if (n->is_Call()) {
285 result->_control.push(n);
286 }
287 }
288 assert(result->_control.contains(other->_end), "what?");
289 assert(result->_control.contains(_begin), "what?");
290 for (int x = 0; x < num_arguments(); x++) {
291 Node* argx = argument_uncast(x);
292 if (argx == arg) {
293 // replace the toString result with the all the arguments that
294 // made up the other StringConcat
295 for (int y = 0; y < other->num_arguments(); y++) {
296 result->append(other->argument(y), other->mode(y));
297 }
298 } else {
299 result->append(argx, mode(x));
300 }
301 }
302 result->set_allocation(other->_begin);
303 result->_multiple = true;
304 return result;
305 }
306
307
308 void StringConcat::eliminate_call(CallNode* call) {
309 Compile* C = _stringopts->C;
310 CallProjections projs;
311 call->extract_projections(&projs, false);
312 if (projs.fallthrough_catchproj != NULL) {
313 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
314 }
315 if (projs.fallthrough_memproj != NULL) {
316 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
317 }
318 if (projs.catchall_memproj != NULL) {
319 C->gvn_replace_by(projs.catchall_memproj, C->top());
320 }
321 if (projs.fallthrough_ioproj != NULL) {
322 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
323 }
324 if (projs.catchall_ioproj != NULL) {
325 C->gvn_replace_by(projs.catchall_ioproj, C->top());
326 }
327 if (projs.catchall_catchproj != NULL) {
328 // EA can't cope with the partially collapsed graph this
329 // creates so put it on the worklist to be collapsed later.
330 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
331 Node *use = i.get();
332 int opc = use->Opcode();
333 if (opc == Op_CreateEx || opc == Op_Region) {
334 _stringopts->record_dead_node(use);
335 }
336 }
337 C->gvn_replace_by(projs.catchall_catchproj, C->top());
338 }
339 if (projs.resproj != NULL) {
340 C->gvn_replace_by(projs.resproj, C->top());
341 }
342 C->gvn_replace_by(call, C->top());
343 }
344
345 void StringConcat::eliminate_initialize(InitializeNode* init) {
346 Compile* C = _stringopts->C;
347
348 // Eliminate Initialize node.
349 assert(init->outcnt() <= 2, "only a control and memory projection expected");
350 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
351 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
352 if (ctrl_proj != NULL) {
353 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
354 }
355 Node *mem_proj = init->proj_out(TypeFunc::Memory);
356 if (mem_proj != NULL) {
357 Node *mem = init->in(TypeFunc::Memory);
358 C->gvn_replace_by(mem_proj, mem);
359 }
360 C->gvn_replace_by(init, C->top());
361 init->disconnect_inputs(NULL, C);
362 }
363
364 Node_List PhaseStringOpts::collect_toString_calls() {
365 Node_List string_calls;
366 Node_List worklist;
367
368 _visited.Clear();
369
370 // Prime the worklist
371 for (uint i = 1; i < C->root()->len(); i++) {
372 Node* n = C->root()->in(i);
373 if (n != NULL && !_visited.test_set(n->_idx)) {
374 worklist.push(n);
375 }
376 }
377
378 while (worklist.size() > 0) {
379 Node* ctrl = worklist.pop();
380 if (StringConcat::is_SB_toString(ctrl)) {
381 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
382 string_calls.push(csj);
383 }
384 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
385 worklist.push(ctrl->in(0));
386 }
387 if (ctrl->is_Region()) {
388 for (uint i = 1; i < ctrl->len(); i++) {
389 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
390 worklist.push(ctrl->in(i));
391 }
392 }
393 }
394 }
395 return string_calls;
396 }
397
398
399 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
400 ciMethod* m = call->method();
401 ciSymbol* string_sig;
402 ciSymbol* int_sig;
403 ciSymbol* char_sig;
404 if (m->holder() == C->env()->StringBuilder_klass()) {
405 string_sig = ciSymbol::String_StringBuilder_signature();
406 int_sig = ciSymbol::int_StringBuilder_signature();
407 char_sig = ciSymbol::char_StringBuilder_signature();
408 } else if (m->holder() == C->env()->StringBuffer_klass()) {
409 string_sig = ciSymbol::String_StringBuffer_signature();
410 int_sig = ciSymbol::int_StringBuffer_signature();
411 char_sig = ciSymbol::char_StringBuffer_signature();
412 } else {
413 return NULL;
414 }
415 #ifndef PRODUCT
416 if (PrintOptimizeStringConcat) {
417 tty->print("considering toString call in ");
418 call->jvms()->dump_spec(tty); tty->cr();
419 }
420 #endif
421
422 StringConcat* sc = new StringConcat(this, call);
423
424 AllocateNode* alloc = NULL;
425 InitializeNode* init = NULL;
426
427 // possible opportunity for StringBuilder fusion
428 CallStaticJavaNode* cnode = call;
429 while (cnode) {
430 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
431 if (recv->is_Proj()) {
432 recv = recv->in(0);
433 }
434 cnode = recv->isa_CallStaticJava();
435 if (cnode == NULL) {
436 alloc = recv->isa_Allocate();
437 if (alloc == NULL) {
438 break;
439 }
440 // Find the constructor call
441 Node* result = alloc->result_cast();
442 if (result == NULL || !result->is_CheckCastPP()) {
443 // strange looking allocation
444 #ifndef PRODUCT
445 if (PrintOptimizeStringConcat) {
446 tty->print("giving up because allocation looks strange ");
447 alloc->jvms()->dump_spec(tty); tty->cr();
448 }
449 #endif
450 break;
451 }
452 Node* constructor = NULL;
453 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
454 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
455 if (use != NULL &&
456 use->method() != NULL &&
457 !use->method()->is_static() &&
458 use->method()->name() == ciSymbol::object_initializer_name() &&
459 use->method()->holder() == m->holder()) {
460 // Matched the constructor.
461 ciSymbol* sig = use->method()->signature()->as_symbol();
462 if (sig == ciSymbol::void_method_signature() ||
463 sig == ciSymbol::int_void_signature() ||
464 sig == ciSymbol::string_void_signature()) {
465 if (sig == ciSymbol::string_void_signature()) {
466 // StringBuilder(String) so pick this up as the first argument
467 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
468 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
469 if (type == TypePtr::NULL_PTR) {
470 // StringBuilder(null) throws exception.
471 #ifndef PRODUCT
472 if (PrintOptimizeStringConcat) {
473 tty->print("giving up because StringBuilder(null) throws exception");
474 alloc->jvms()->dump_spec(tty); tty->cr();
475 }
476 #endif
477 return NULL;
478 }
479 // StringBuilder(str) argument needs null check.
480 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
481 }
482 // The int variant takes an initial size for the backing
483 // array so just treat it like the void version.
484 constructor = use;
485 } else {
486 #ifndef PRODUCT
487 if (PrintOptimizeStringConcat) {
488 tty->print("unexpected constructor signature: %s", sig->as_utf8());
489 }
490 #endif
491 }
492 break;
493 }
494 }
495 if (constructor == NULL) {
496 // couldn't find constructor
497 #ifndef PRODUCT
498 if (PrintOptimizeStringConcat) {
499 tty->print("giving up because couldn't find constructor ");
500 alloc->jvms()->dump_spec(tty); tty->cr();
501 }
502 #endif
503 break;
504 }
505
506 // Walked all the way back and found the constructor call so see
507 // if this call converted into a direct string concatenation.
508 sc->add_control(call);
509 sc->add_control(constructor);
510 sc->add_control(alloc);
511 sc->set_allocation(alloc);
512 if (sc->validate_control_flow()) {
513 return sc;
514 } else {
515 return NULL;
516 }
517 } else if (cnode->method() == NULL) {
518 break;
519 } else if (!cnode->method()->is_static() &&
520 cnode->method()->holder() == m->holder() &&
521 cnode->method()->name() == ciSymbol::append_name() &&
522 (cnode->method()->signature()->as_symbol() == string_sig ||
523 cnode->method()->signature()->as_symbol() == char_sig ||
524 cnode->method()->signature()->as_symbol() == int_sig)) {
525 sc->add_control(cnode);
526 Node* arg = cnode->in(TypeFunc::Parms + 1);
527 if (cnode->method()->signature()->as_symbol() == int_sig) {
528 sc->push_int(arg);
529 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
530 sc->push_char(arg);
531 } else {
532 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
533 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
534 if (csj->method() != NULL &&
535 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
536 arg->outcnt() == 1) {
537 // _control is the list of StringBuilder calls nodes which
538 // will be replaced by new String code after this optimization.
539 // Integer::toString() call is not part of StringBuilder calls
540 // chain. It could be eliminated only if its result is used
541 // only by this SB calls chain.
542 // Another limitation: it should be used only once because
543 // it is unknown that it is used only by this SB calls chain
544 // until all related SB calls nodes are collected.
545 assert(arg->unique_out() == cnode, "sanity");
546 sc->add_control(csj);
547 sc->push_int(csj->in(TypeFunc::Parms));
548 continue;
549 }
550 }
551 sc->push_string(arg);
552 }
553 continue;
554 } else {
555 // some unhandled signature
556 #ifndef PRODUCT
557 if (PrintOptimizeStringConcat) {
558 tty->print("giving up because encountered unexpected signature ");
559 cnode->tf()->dump(); tty->cr();
560 cnode->in(TypeFunc::Parms + 1)->dump();
561 }
562 #endif
563 break;
564 }
565 }
566 return NULL;
567 }
568
569
570 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
571 Phase(StringOpts),
572 _gvn(gvn),
573 _visited(Thread::current()->resource_area()) {
574
575 assert(OptimizeStringConcat, "shouldn't be here");
576
577 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
578 ciSymbol::make("[I"), true);
579 if (size_table_field == NULL) {
580 // Something wrong so give up.
581 assert(false, "why can't we find Integer.sizeTable?");
582 return;
583 }
584
585 // Collect the types needed to talk about the various slices of memory
586 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
587
588 // For each locally allocated StringBuffer see if the usages can be
589 // collapsed into a single String construction.
590
591 // Run through the list of allocation looking for SB.toString to see
592 // if it's possible to fuse the usage of the SB into a single String
593 // construction.
594 GrowableArray<StringConcat*> concats;
595 Node_List toStrings = collect_toString_calls();
596 while (toStrings.size() > 0) {
597 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
598 if (sc != NULL) {
599 concats.push(sc);
600 }
601 }
602
603 // try to coalesce separate concats
604 restart:
605 for (int c = 0; c < concats.length(); c++) {
606 StringConcat* sc = concats.at(c);
607 for (int i = 0; i < sc->num_arguments(); i++) {
608 Node* arg = sc->argument_uncast(i);
609 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
610 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
611 for (int o = 0; o < concats.length(); o++) {
612 if (c == o) continue;
613 StringConcat* other = concats.at(o);
614 if (other->end() == csj) {
615 #ifndef PRODUCT
616 if (PrintOptimizeStringConcat) {
617 tty->print_cr("considering stacked concats");
618 }
619 #endif
620
621 StringConcat* merged = sc->merge(other, arg);
622 if (merged->validate_control_flow()) {
623 #ifndef PRODUCT
624 if (PrintOptimizeStringConcat) {
625 tty->print_cr("stacking would succeed");
626 }
627 #endif
628 if (c < o) {
629 concats.remove_at(o);
630 concats.at_put(c, merged);
631 } else {
632 concats.remove_at(c);
633 concats.at_put(o, merged);
634 }
635 goto restart;
636 } else {
637 #ifndef PRODUCT
638 if (PrintOptimizeStringConcat) {
639 tty->print_cr("stacking would fail");
640 }
641 #endif
642 }
643 }
644 }
645 }
646 }
647 }
648
649
650 for (int c = 0; c < concats.length(); c++) {
651 StringConcat* sc = concats.at(c);
652 replace_string_concat(sc);
653 }
654
655 remove_dead_nodes();
656 }
657
658 void PhaseStringOpts::record_dead_node(Node* dead) {
659 dead_worklist.push(dead);
660 }
661
662 void PhaseStringOpts::remove_dead_nodes() {
663 // Delete any dead nodes to make things clean enough that escape
664 // analysis doesn't get unhappy.
665 while (dead_worklist.size() > 0) {
666 Node* use = dead_worklist.pop();
667 int opc = use->Opcode();
668 switch (opc) {
669 case Op_Region: {
670 uint i = 1;
671 for (i = 1; i < use->req(); i++) {
672 if (use->in(i) != C->top()) {
673 break;
674 }
675 }
676 if (i >= use->req()) {
677 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
678 Node* m = i.get();
679 if (m->is_Phi()) {
680 dead_worklist.push(m);
681 }
682 }
683 C->gvn_replace_by(use, C->top());
684 }
685 break;
686 }
687 case Op_AddP:
688 case Op_CreateEx: {
689 // Recurisvely clean up references to CreateEx so EA doesn't
690 // get unhappy about the partially collapsed graph.
691 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
692 Node* m = i.get();
693 if (m->is_AddP()) {
694 dead_worklist.push(m);
695 }
696 }
697 C->gvn_replace_by(use, C->top());
698 break;
699 }
700 case Op_Phi:
701 if (use->in(0) == C->top()) {
702 C->gvn_replace_by(use, C->top());
703 }
704 break;
705 }
706 }
707 }
708
709
710 bool StringConcat::validate_control_flow() {
711 // We found all the calls and arguments now lets see if it's
712 // safe to transform the graph as we would expect.
713
714 // Check to see if this resulted in too many uncommon traps previously
715 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
716 Deoptimization::Reason_intrinsic)) {
717 return false;
718 }
719
720 // Walk backwards over the control flow from toString to the
721 // allocation and make sure all the control flow is ok. This
722 // means it's either going to be eliminated once the calls are
723 // removed or it can safely be transformed into an uncommon
724 // trap.
725
726 int null_check_count = 0;
727 Unique_Node_List ctrl_path;
728
729 assert(_control.contains(_begin), "missing");
730 assert(_control.contains(_end), "missing");
731
732 // Collect the nodes that we know about and will eliminate into ctrl_path
733 for (uint i = 0; i < _control.size(); i++) {
734 // Push the call and it's control projection
735 Node* n = _control.at(i);
736 if (n->is_Allocate()) {
737 AllocateNode* an = n->as_Allocate();
738 InitializeNode* init = an->initialization();
739 ctrl_path.push(init);
740 ctrl_path.push(init->as_Multi()->proj_out(0));
741 }
742 if (n->is_Call()) {
743 CallNode* cn = n->as_Call();
744 ctrl_path.push(cn);
745 ctrl_path.push(cn->proj_out(0));
746 ctrl_path.push(cn->proj_out(0)->unique_out());
747 if (cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0) != NULL) {
748 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
749 }
750 } else {
751 ShouldNotReachHere();
752 }
753 }
754
755 // Skip backwards through the control checking for unexpected contro flow
756 Node* ptr = _end;
757 bool fail = false;
758 while (ptr != _begin) {
759 if (ptr->is_Call() && ctrl_path.member(ptr)) {
760 ptr = ptr->in(0);
761 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
762 ptr = ptr->in(0)->in(0)->in(0);
763 assert(ctrl_path.member(ptr), "should be a known piece of control");
764 } else if (ptr->is_IfTrue()) {
765 IfNode* iff = ptr->in(0)->as_If();
766 BoolNode* b = iff->in(1)->isa_Bool();
767
768 if (b == NULL) {
769 fail = true;
770 break;
771 }
772
773 Node* cmp = b->in(1);
774 Node* v1 = cmp->in(1);
775 Node* v2 = cmp->in(2);
776 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
777
778 // Null check of the return of append which can simply be eliminated
779 if (b->_test._test == BoolTest::ne &&
780 v2->bottom_type() == TypePtr::NULL_PTR &&
781 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
782 // NULL check of the return value of the append
783 null_check_count++;
784 if (otherproj->outcnt() == 1) {
785 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
786 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
787 ctrl_path.push(call);
788 }
789 }
790 _control.push(ptr);
791 ptr = ptr->in(0)->in(0);
792 continue;
793 }
794
795 // A test which leads to an uncommon trap which should be safe.
796 // Later this trap will be converted into a trap that restarts
797 // at the beginning.
798 if (otherproj->outcnt() == 1) {
799 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
800 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
801 // control flow leads to uct so should be ok
802 _uncommon_traps.push(call);
803 ctrl_path.push(call);
804 ptr = ptr->in(0)->in(0);
805 continue;
806 }
807 }
808
809 #ifndef PRODUCT
810 // Some unexpected control flow we don't know how to handle.
811 if (PrintOptimizeStringConcat) {
812 tty->print_cr("failing with unknown test");
813 b->dump();
814 cmp->dump();
815 v1->dump();
816 v2->dump();
817 tty->cr();
818 }
819 #endif
820 fail = true;
821 break;
822 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
823 ptr = ptr->in(0)->in(0);
824 } else if (ptr->is_Region()) {
825 Node* copy = ptr->as_Region()->is_copy();
826 if (copy != NULL) {
827 ptr = copy;
828 continue;
829 }
830 if (ptr->req() == 3 &&
831 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
832 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
833 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
834 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
835 // Simple diamond.
836 // XXX should check for possibly merging stores. simple data merges are ok.
837 ptr = ptr->in(1)->in(0)->in(0);
838 continue;
839 }
840 #ifndef PRODUCT
841 if (PrintOptimizeStringConcat) {
842 tty->print_cr("fusion would fail for region");
843 _begin->dump();
844 ptr->dump(2);
845 }
846 #endif
847 fail = true;
848 break;
849 } else {
850 // other unknown control
851 if (!fail) {
852 #ifndef PRODUCT
853 if (PrintOptimizeStringConcat) {
854 tty->print_cr("fusion would fail for");
855 _begin->dump();
856 }
857 #endif
858 fail = true;
859 }
860 #ifndef PRODUCT
861 if (PrintOptimizeStringConcat) {
862 ptr->dump();
863 }
864 #endif
865 ptr = ptr->in(0);
866 }
867 }
868 #ifndef PRODUCT
869 if (PrintOptimizeStringConcat && fail) {
870 tty->cr();
871 }
872 #endif
873 if (fail) return !fail;
874
875 // Validate that all these results produced are contained within
876 // this cluster of objects. First collect all the results produced
877 // by calls in the region.
878 _stringopts->_visited.Clear();
879 Node_List worklist;
880 Node* final_result = _end->proj_out(TypeFunc::Parms);
881 for (uint i = 0; i < _control.size(); i++) {
882 CallNode* cnode = _control.at(i)->isa_Call();
883 if (cnode != NULL) {
884 _stringopts->_visited.test_set(cnode->_idx);
885 }
886 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
887 if (result != NULL && result != final_result) {
888 worklist.push(result);
889 }
890 }
891
892 Node* last_result = NULL;
893 while (worklist.size() > 0) {
894 Node* result = worklist.pop();
895 if (_stringopts->_visited.test_set(result->_idx))
896 continue;
897 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
898 Node *use = i.get();
899 if (ctrl_path.member(use)) {
900 // already checked this
901 continue;
902 }
903 int opc = use->Opcode();
904 if (opc == Op_CmpP || opc == Op_Node) {
905 ctrl_path.push(use);
906 continue;
907 }
908 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
909 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
910 worklist.push(j.get());
911 }
912 worklist.push(use->in(1));
913 ctrl_path.push(use);
914 continue;
915 }
916 #ifndef PRODUCT
917 if (PrintOptimizeStringConcat) {
918 if (result != last_result) {
919 last_result = result;
920 tty->print_cr("extra uses for result:");
921 last_result->dump();
922 }
923 use->dump();
924 }
925 #endif
926 fail = true;
927 break;
928 }
929 }
930
931 #ifndef PRODUCT
932 if (PrintOptimizeStringConcat && !fail) {
933 ttyLocker ttyl;
934 tty->cr();
935 tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
936 _begin->jvms()->dump_spec(tty); tty->cr();
937 for (int i = 0; i < num_arguments(); i++) {
938 argument(i)->dump();
939 }
940 _control.dump();
941 tty->cr();
942 }
943 #endif
944
945 return !fail;
946 }
947
948 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
949 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
950 Node* klass_node = __ makecon(mirror_type);
951 BasicType bt = field->layout_type();
952 ciType* field_klass = field->type();
953
954 const Type *type;
955 if( bt == T_OBJECT ) {
956 if (!field->type()->is_loaded()) {
957 type = TypeInstPtr::BOTTOM;
958 } else if (field->is_constant()) {
959 // This can happen if the constant oop is non-perm.
960 ciObject* con = field->constant_value().as_object();
961 // Do not "join" in the previous type; it doesn't add value,
962 // and may yield a vacuous result if the field is of interface type.
963 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
964 assert(type != NULL, "field singleton type must be consistent");
965 return __ makecon(type);
966 } else {
967 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
968 }
969 } else {
970 type = Type::get_const_basic_type(bt);
971 }
972
973 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
974 type, T_OBJECT,
975 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())));
976 }
977
978 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
979 RegionNode *final_merge = new (C) RegionNode(3);
980 kit.gvn().set_type(final_merge, Type::CONTROL);
981 Node* final_size = new (C) PhiNode(final_merge, TypeInt::INT);
982 kit.gvn().set_type(final_size, TypeInt::INT);
983
984 IfNode* iff = kit.create_and_map_if(kit.control(),
985 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
986 PROB_FAIR, COUNT_UNKNOWN);
987 Node* is_min = __ IfFalse(iff);
988 final_merge->init_req(1, is_min);
989 final_size->init_req(1, __ intcon(11));
990
991 kit.set_control(__ IfTrue(iff));
992 if (kit.stopped()) {
993 final_merge->init_req(2, C->top());
994 final_size->init_req(2, C->top());
995 } else {
996
997 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
998 RegionNode *r = new (C) RegionNode(3);
999 kit.gvn().set_type(r, Type::CONTROL);
1000 Node *phi = new (C) PhiNode(r, TypeInt::INT);
1001 kit.gvn().set_type(phi, TypeInt::INT);
1002 Node *size = new (C) PhiNode(r, TypeInt::INT);
1003 kit.gvn().set_type(size, TypeInt::INT);
1004 Node* chk = __ CmpI(arg, __ intcon(0));
1005 Node* p = __ Bool(chk, BoolTest::lt);
1006 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1007 Node* lessthan = __ IfTrue(iff);
1008 Node* greaterequal = __ IfFalse(iff);
1009 r->init_req(1, lessthan);
1010 phi->init_req(1, __ SubI(__ intcon(0), arg));
1011 size->init_req(1, __ intcon(1));
1012 r->init_req(2, greaterequal);
1013 phi->init_req(2, arg);
1014 size->init_req(2, __ intcon(0));
1015 kit.set_control(r);
1016 C->record_for_igvn(r);
1017 C->record_for_igvn(phi);
1018 C->record_for_igvn(size);
1019
1020 // for (int i=0; ; i++)
1021 // if (x <= sizeTable[i])
1022 // return i+1;
1023
1024 // Add loop predicate first.
1025 kit.add_predicate();
1026
1027 RegionNode *loop = new (C) RegionNode(3);
1028 loop->init_req(1, kit.control());
1029 kit.gvn().set_type(loop, Type::CONTROL);
1030
1031 Node *index = new (C) PhiNode(loop, TypeInt::INT);
1032 index->init_req(1, __ intcon(0));
1033 kit.gvn().set_type(index, TypeInt::INT);
1034 kit.set_control(loop);
1035 Node* sizeTable = fetch_static_field(kit, size_table_field);
1036
1037 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1038 C->record_for_igvn(value);
1039 Node* limit = __ CmpI(phi, value);
1040 Node* limitb = __ Bool(limit, BoolTest::le);
1041 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1042 Node* lessEqual = __ IfTrue(iff2);
1043 Node* greater = __ IfFalse(iff2);
1044
1045 loop->init_req(2, greater);
1046 index->init_req(2, __ AddI(index, __ intcon(1)));
1047
1048 kit.set_control(lessEqual);
1049 C->record_for_igvn(loop);
1050 C->record_for_igvn(index);
1051
1052 final_merge->init_req(2, kit.control());
1053 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1054 }
1055
1056 kit.set_control(final_merge);
1057 C->record_for_igvn(final_merge);
1058 C->record_for_igvn(final_size);
1059
1060 return final_size;
1061 }
1062
1063 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1064 RegionNode *final_merge = new (C) RegionNode(4);
1065 kit.gvn().set_type(final_merge, Type::CONTROL);
1066 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1067 kit.gvn().set_type(final_mem, Type::MEMORY);
1068
1069 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1070 {
1071 // i == MIN_VALUE
1072 IfNode* iff = kit.create_and_map_if(kit.control(),
1073 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1074 PROB_FAIR, COUNT_UNKNOWN);
1075
1076 Node* old_mem = kit.memory(char_adr_idx);
1077
1078 kit.set_control(__ IfFalse(iff));
1079 if (kit.stopped()) {
1080 // Statically not equal to MIN_VALUE so this path is dead
1081 final_merge->init_req(3, kit.control());
1082 } else {
1083 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1084 char_array, start);
1085 final_merge->init_req(3, kit.control());
1086 final_mem->init_req(3, kit.memory(char_adr_idx));
1087 }
1088
1089 kit.set_control(__ IfTrue(iff));
1090 kit.set_memory(old_mem, char_adr_idx);
1091 }
1092
1093
1094 // Simplified version of Integer.getChars
1095
1096 // int q, r;
1097 // int charPos = index;
1098 Node* charPos = end;
1099
1100 // char sign = 0;
1101
1102 Node* i = arg;
1103 Node* sign = __ intcon(0);
1104
1105 // if (i < 0) {
1106 // sign = '-';
1107 // i = -i;
1108 // }
1109 {
1110 IfNode* iff = kit.create_and_map_if(kit.control(),
1111 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1112 PROB_FAIR, COUNT_UNKNOWN);
1113
1114 RegionNode *merge = new (C) RegionNode(3);
1115 kit.gvn().set_type(merge, Type::CONTROL);
1116 i = new (C) PhiNode(merge, TypeInt::INT);
1117 kit.gvn().set_type(i, TypeInt::INT);
1118 sign = new (C) PhiNode(merge, TypeInt::INT);
1119 kit.gvn().set_type(sign, TypeInt::INT);
1120
1121 merge->init_req(1, __ IfTrue(iff));
1122 i->init_req(1, __ SubI(__ intcon(0), arg));
1123 sign->init_req(1, __ intcon('-'));
1124 merge->init_req(2, __ IfFalse(iff));
1125 i->init_req(2, arg);
1126 sign->init_req(2, __ intcon(0));
1127
1128 kit.set_control(merge);
1129
1130 C->record_for_igvn(merge);
1131 C->record_for_igvn(i);
1132 C->record_for_igvn(sign);
1133 }
1134
1135 // for (;;) {
1136 // q = i / 10;
1137 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1138 // buf [--charPos] = digits [r];
1139 // i = q;
1140 // if (i == 0) break;
1141 // }
1142
1143 {
1144 // Add loop predicate first.
1145 kit.add_predicate();
1146
1147 RegionNode *head = new (C) RegionNode(3);
1148 head->init_req(1, kit.control());
1149 kit.gvn().set_type(head, Type::CONTROL);
1150 Node *i_phi = new (C) PhiNode(head, TypeInt::INT);
1151 i_phi->init_req(1, i);
1152 kit.gvn().set_type(i_phi, TypeInt::INT);
1153 charPos = PhiNode::make(head, charPos);
1154 kit.gvn().set_type(charPos, TypeInt::INT);
1155 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1156 kit.gvn().set_type(mem, Type::MEMORY);
1157 kit.set_control(head);
1158 kit.set_memory(mem, char_adr_idx);
1159
1160 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1161 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1162 __ LShiftI(q, __ intcon(1))));
1163 Node* m1 = __ SubI(charPos, __ intcon(1));
1164 Node* ch = __ AddI(r, __ intcon('0'));
1165
1166 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1167 ch, T_CHAR, char_adr_idx);
1168
1169
1170 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1171 PROB_FAIR, COUNT_UNKNOWN);
1172 Node* ne = __ IfTrue(iff);
1173 Node* eq = __ IfFalse(iff);
1174
1175 head->init_req(2, ne);
1176 mem->init_req(2, st);
1177 i_phi->init_req(2, q);
1178 charPos->init_req(2, m1);
1179
1180 charPos = m1;
1181
1182 kit.set_control(eq);
1183 kit.set_memory(st, char_adr_idx);
1184
1185 C->record_for_igvn(head);
1186 C->record_for_igvn(mem);
1187 C->record_for_igvn(i_phi);
1188 C->record_for_igvn(charPos);
1189 }
1190
1191 {
1192 // if (sign != 0) {
1193 // buf [--charPos] = sign;
1194 // }
1195 IfNode* iff = kit.create_and_map_if(kit.control(),
1196 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1197 PROB_FAIR, COUNT_UNKNOWN);
1198
1199 final_merge->init_req(2, __ IfFalse(iff));
1200 final_mem->init_req(2, kit.memory(char_adr_idx));
1201
1202 kit.set_control(__ IfTrue(iff));
1203 if (kit.stopped()) {
1204 final_merge->init_req(1, C->top());
1205 final_mem->init_req(1, C->top());
1206 } else {
1207 Node* m1 = __ SubI(charPos, __ intcon(1));
1208 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1209 sign, T_CHAR, char_adr_idx);
1210
1211 final_merge->init_req(1, kit.control());
1212 final_mem->init_req(1, st);
1213 }
1214
1215 kit.set_control(final_merge);
1216 kit.set_memory(final_mem, char_adr_idx);
1217
1218 C->record_for_igvn(final_merge);
1219 C->record_for_igvn(final_mem);
1220 }
1221 }
1222
1223
1224 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1225 Node* string = str;
1226 Node* offset = kit.load_String_offset(kit.control(), string);
1227 Node* count = kit.load_String_length(kit.control(), string);
1228 Node* value = kit.load_String_value (kit.control(), string);
1229
1230 // copy the contents
1231 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1232 // For small constant strings just emit individual stores.
1233 // A length of 6 seems like a good space/speed tradeof.
1234 int c = count->get_int();
1235 int o = offset->get_int();
1236 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1237 ciTypeArray* value_array = t->const_oop()->as_type_array();
1238 for (int e = 0; e < c; e++) {
1239 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1240 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1241 start = __ AddI(start, __ intcon(1));
1242 }
1243 } else {
1244 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1245 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1246 Node* c = count;
1247 Node* extra = NULL;
1248 #ifdef _LP64
1249 c = __ ConvI2L(c);
1250 extra = C->top();
1251 #endif
1252 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1253 OptoRuntime::fast_arraycopy_Type(),
1254 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1255 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1256 src_ptr, dst_ptr, c, extra);
1257 start = __ AddI(start, count);
1258 }
1259 return start;
1260 }
1261
1262
1263 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1264 // Log a little info about the transformation
1265 sc->maybe_log_transform();
1266
1267 // pull the JVMState of the allocation into a SafePointNode to serve as
1268 // as a shim for the insertion of the new code.
1269 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1270 uint size = sc->begin()->req();
1271 SafePointNode* map = new (C) SafePointNode(size, jvms);
1272
1273 // copy the control and memory state from the final call into our
1274 // new starting state. This allows any preceeding tests to feed
1275 // into the new section of code.
1276 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1277 map->init_req(i1, sc->end()->in(i1));
1278 }
1279 // blow away old allocation arguments
1280 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1281 map->init_req(i1, C->top());
1282 }
1283 // Copy the rest of the inputs for the JVMState
1284 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1285 map->init_req(i1, sc->begin()->in(i1));
1286 }
1287 // Make sure the memory state is a MergeMem for parsing.
1288 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1289 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1290 }
1291
1292 jvms->set_map(map);
1293 map->ensure_stack(jvms, jvms->method()->max_stack());
1294
1295
1296 // disconnect all the old StringBuilder calls from the graph
1297 sc->eliminate_unneeded_control();
1298
1299 // At this point all the old work has been completely removed from
1300 // the graph and the saved JVMState exists at the point where the
1301 // final toString call used to be.
1302 GraphKit kit(jvms);
1303
1304 // There may be uncommon traps which are still using the
1305 // intermediate states and these need to be rewritten to point at
1306 // the JVMState at the beginning of the transformation.
1307 sc->convert_uncommon_traps(kit, jvms);
1308
1309 // Now insert the logic to compute the size of the string followed
1310 // by all the logic to construct array and resulting string.
1311
1312 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1313
1314 // Create a region for the overflow checks to merge into.
1315 int args = MAX2(sc->num_arguments(), 1);
1316 RegionNode* overflow = new (C) RegionNode(args);
1317 kit.gvn().set_type(overflow, Type::CONTROL);
1318
1319 // Create a hook node to hold onto the individual sizes since they
1320 // are need for the copying phase.
1321 Node* string_sizes = new (C) Node(args);
1322
1323 Node* length = __ intcon(0);
1324 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1325 Node* arg = sc->argument(argi);
1326 switch (sc->mode(argi)) {
1327 case StringConcat::IntMode: {
1328 Node* string_size = int_stringSize(kit, arg);
1329
1330 // accumulate total
1331 length = __ AddI(length, string_size);
1332
1333 // Cache this value for the use by int_toString
1334 string_sizes->init_req(argi, string_size);
1335 break;
1336 }
1337 case StringConcat::StringNullCheckMode: {
1338 const Type* type = kit.gvn().type(arg);
1339 assert(type != TypePtr::NULL_PTR, "missing check");
1340 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1341 // Null check with uncommont trap since
1342 // StringBuilder(null) throws exception.
1343 // Use special uncommon trap instead of
1344 // calling normal do_null_check().
1345 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1346 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1347 overflow->add_req(__ IfFalse(iff));
1348 Node* notnull = __ IfTrue(iff);
1349 kit.set_control(notnull); // set control for the cast_not_null
1350 arg = kit.cast_not_null(arg, false);
1351 sc->set_argument(argi, arg);
1352 }
1353 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1354 // Fallthrough to add string length.
1355 }
1356 case StringConcat::StringMode: {
1357 const Type* type = kit.gvn().type(arg);
1358 if (type == TypePtr::NULL_PTR) {
1359 // replace the argument with the null checked version
1360 arg = null_string;
1361 sc->set_argument(argi, arg);
1362 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1363 // s = s != null ? s : "null";
1364 // length = length + (s.count - s.offset);
1365 RegionNode *r = new (C) RegionNode(3);
1366 kit.gvn().set_type(r, Type::CONTROL);
1367 Node *phi = new (C) PhiNode(r, type);
1368 kit.gvn().set_type(phi, phi->bottom_type());
1369 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1370 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1371 Node* notnull = __ IfTrue(iff);
1372 Node* isnull = __ IfFalse(iff);
1373 kit.set_control(notnull); // set control for the cast_not_null
1374 r->init_req(1, notnull);
1375 phi->init_req(1, kit.cast_not_null(arg, false));
1376 r->init_req(2, isnull);
1377 phi->init_req(2, null_string);
1378 kit.set_control(r);
1379 C->record_for_igvn(r);
1380 C->record_for_igvn(phi);
1381 // replace the argument with the null checked version
1382 arg = phi;
1383 sc->set_argument(argi, arg);
1384 }
1385
1386 Node* count = kit.load_String_length(kit.control(), arg);
1387
1388 length = __ AddI(length, count);
1389 string_sizes->init_req(argi, NULL);
1390 break;
1391 }
1392 case StringConcat::CharMode: {
1393 // one character only
1394 length = __ AddI(length, __ intcon(1));
1395 break;
1396 }
1397 default:
1398 ShouldNotReachHere();
1399 }
1400 if (argi > 0) {
1401 // Check that the sum hasn't overflowed
1402 IfNode* iff = kit.create_and_map_if(kit.control(),
1403 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1404 PROB_MIN, COUNT_UNKNOWN);
1405 kit.set_control(__ IfFalse(iff));
1406 overflow->set_req(argi, __ IfTrue(iff));
1407 }
1408 }
1409
1410 {
1411 // Hook
1412 PreserveJVMState pjvms(&kit);
1413 kit.set_control(overflow);
1414 C->record_for_igvn(overflow);
1415 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1416 Deoptimization::Action_make_not_entrant);
1417 }
1418
1419 Node* result;
1420 if (!kit.stopped()) {
1421
1422 // length now contains the number of characters needed for the
1423 // char[] so create a new AllocateArray for the char[]
1424 Node* char_array = NULL;
1425 {
1426 PreserveReexecuteState preexecs(&kit);
1427 // The original jvms is for an allocation of either a String or
1428 // StringBuffer so no stack adjustment is necessary for proper
1429 // reexecution. If we deoptimize in the slow path the bytecode
1430 // will be reexecuted and the char[] allocation will be thrown away.
1431 kit.jvms()->set_should_reexecute(true);
1432 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1433 length, 1);
1434 }
1435
1436 // Mark the allocation so that zeroing is skipped since the code
1437 // below will overwrite the entire array
1438 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1439 char_alloc->maybe_set_complete(_gvn);
1440
1441 // Now copy the string representations into the final char[]
1442 Node* start = __ intcon(0);
1443 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1444 Node* arg = sc->argument(argi);
1445 switch (sc->mode(argi)) {
1446 case StringConcat::IntMode: {
1447 Node* end = __ AddI(start, string_sizes->in(argi));
1448 // getChars words backwards so pass the ending point as well as the start
1449 int_getChars(kit, arg, char_array, start, end);
1450 start = end;
1451 break;
1452 }
1453 case StringConcat::StringNullCheckMode:
1454 case StringConcat::StringMode: {
1455 start = copy_string(kit, arg, char_array, start);
1456 break;
1457 }
1458 case StringConcat::CharMode: {
1459 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1460 arg, T_CHAR, char_adr_idx);
1461 start = __ AddI(start, __ intcon(1));
1462 break;
1463 }
1464 default:
1465 ShouldNotReachHere();
1466 }
1467 }
1468
1469 // If we're not reusing an existing String allocation then allocate one here.
1470 result = sc->string_alloc();
1471 if (result == NULL) {
1472 PreserveReexecuteState preexecs(&kit);
1473 // The original jvms is for an allocation of either a String or
1474 // StringBuffer so no stack adjustment is necessary for proper
1475 // reexecution.
1476 kit.jvms()->set_should_reexecute(true);
1477 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1478 }
1479
1480 // Intialize the string
1481 if (java_lang_String::has_offset_field()) {
1482 kit.store_String_offset(kit.control(), result, __ intcon(0));
1483 kit.store_String_length(kit.control(), result, length);
1484 }
1485 kit.store_String_value(kit.control(), result, char_array);
1486 } else {
1487 result = C->top();
1488 }
1489 // hook up the outgoing control and result
1490 kit.replace_call(sc->end(), result);
1491
1492 // Unhook any hook nodes
1493 string_sizes->disconnect_inputs(NULL, C);
1494 sc->cleanup();
1495 }