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