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 value = 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 sc->add_control(csj);
538 sc->push_int(csj->in(TypeFunc::Parms));
539 continue;
540 }
541 }
542 sc->push_string(arg);
543 }
544 continue;
545 } else {
546 // some unhandled signature
547 #ifndef PRODUCT
548 if (PrintOptimizeStringConcat) {
549 tty->print("giving up because encountered unexpected signature ");
550 cnode->tf()->dump(); tty->cr();
551 cnode->in(TypeFunc::Parms + 1)->dump();
552 }
553 #endif
554 break;
555 }
556 }
557 return NULL;
558 }
559
560
561 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
562 Phase(StringOpts),
563 _gvn(gvn),
564 _visited(Thread::current()->resource_area()) {
565
566 assert(OptimizeStringConcat, "shouldn't be here");
567
568 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
569 ciSymbol::make("[I"), true);
570 if (size_table_field == NULL) {
571 // Something wrong so give up.
572 assert(false, "why can't we find Integer.sizeTable?");
573 return;
574 }
575
576 // Collect the types needed to talk about the various slices of memory
577 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
578
579 // For each locally allocated StringBuffer see if the usages can be
580 // collapsed into a single String construction.
581
582 // Run through the list of allocation looking for SB.toString to see
583 // if it's possible to fuse the usage of the SB into a single String
584 // construction.
585 GrowableArray<StringConcat*> concats;
586 Node_List toStrings = collect_toString_calls();
587 while (toStrings.size() > 0) {
588 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
589 if (sc != NULL) {
590 concats.push(sc);
591 }
592 }
593
594 // try to coalesce separate concats
595 restart:
596 for (int c = 0; c < concats.length(); c++) {
597 StringConcat* sc = concats.at(c);
598 for (int i = 0; i < sc->num_arguments(); i++) {
599 Node* arg = sc->argument_uncast(i);
600 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
601 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
602 for (int o = 0; o < concats.length(); o++) {
603 if (c == o) continue;
604 StringConcat* other = concats.at(o);
605 if (other->end() == csj) {
606 #ifndef PRODUCT
607 if (PrintOptimizeStringConcat) {
608 tty->print_cr("considering stacked concats");
609 }
610 #endif
611
612 StringConcat* merged = sc->merge(other, arg);
613 if (merged->validate_control_flow()) {
614 #ifndef PRODUCT
615 if (PrintOptimizeStringConcat) {
616 tty->print_cr("stacking would succeed");
617 }
618 #endif
619 if (c < o) {
620 concats.remove_at(o);
621 concats.at_put(c, merged);
622 } else {
623 concats.remove_at(c);
624 concats.at_put(o, merged);
625 }
626 goto restart;
627 } else {
628 #ifndef PRODUCT
629 if (PrintOptimizeStringConcat) {
630 tty->print_cr("stacking would fail");
631 }
632 #endif
633 }
634 }
635 }
636 }
637 }
638 }
639
640
641 for (int c = 0; c < concats.length(); c++) {
642 StringConcat* sc = concats.at(c);
643 replace_string_concat(sc);
644 }
645
646 remove_dead_nodes();
647 }
648
649 void PhaseStringOpts::record_dead_node(Node* dead) {
650 dead_worklist.push(dead);
651 }
652
653 void PhaseStringOpts::remove_dead_nodes() {
654 // Delete any dead nodes to make things clean enough that escape
655 // analysis doesn't get unhappy.
656 while (dead_worklist.size() > 0) {
657 Node* use = dead_worklist.pop();
658 int opc = use->Opcode();
659 switch (opc) {
660 case Op_Region: {
661 uint i = 1;
662 for (i = 1; i < use->req(); i++) {
663 if (use->in(i) != C->top()) {
664 break;
665 }
666 }
667 if (i >= use->req()) {
668 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
669 Node* m = i.get();
670 if (m->is_Phi()) {
671 dead_worklist.push(m);
672 }
673 }
674 C->gvn_replace_by(use, C->top());
675 }
676 break;
677 }
678 case Op_AddP:
679 case Op_CreateEx: {
680 // Recurisvely clean up references to CreateEx so EA doesn't
681 // get unhappy about the partially collapsed graph.
682 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
683 Node* m = i.get();
684 if (m->is_AddP()) {
685 dead_worklist.push(m);
686 }
687 }
688 C->gvn_replace_by(use, C->top());
689 break;
690 }
691 case Op_Phi:
692 if (use->in(0) == C->top()) {
693 C->gvn_replace_by(use, C->top());
694 }
695 break;
696 }
697 }
698 }
699
700
701 bool StringConcat::validate_control_flow() {
702 // We found all the calls and arguments now lets see if it's
703 // safe to transform the graph as we would expect.
704
705 // Check to see if this resulted in too many uncommon traps previously
706 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
707 Deoptimization::Reason_intrinsic)) {
708 return false;
709 }
710
711 // Walk backwards over the control flow from toString to the
712 // allocation and make sure all the control flow is ok. This
713 // means it's either going to be eliminated once the calls are
714 // removed or it can safely be transformed into an uncommon
715 // trap.
716
717 int null_check_count = 0;
718 Unique_Node_List ctrl_path;
719
720 assert(_control.contains(_begin), "missing");
721 assert(_control.contains(_end), "missing");
722
723 // Collect the nodes that we know about and will eliminate into ctrl_path
724 for (uint i = 0; i < _control.size(); i++) {
725 // Push the call and it's control projection
726 Node* n = _control.at(i);
727 if (n->is_Allocate()) {
728 AllocateNode* an = n->as_Allocate();
729 InitializeNode* init = an->initialization();
730 ctrl_path.push(init);
731 ctrl_path.push(init->as_Multi()->proj_out(0));
732 }
733 if (n->is_Call()) {
734 CallNode* cn = n->as_Call();
735 ctrl_path.push(cn);
736 ctrl_path.push(cn->proj_out(0));
737 ctrl_path.push(cn->proj_out(0)->unique_out());
738 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
739 } else {
740 ShouldNotReachHere();
741 }
742 }
743
744 // Skip backwards through the control checking for unexpected contro flow
745 Node* ptr = _end;
746 bool fail = false;
747 while (ptr != _begin) {
748 if (ptr->is_Call() && ctrl_path.member(ptr)) {
749 ptr = ptr->in(0);
750 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
751 ptr = ptr->in(0)->in(0)->in(0);
752 assert(ctrl_path.member(ptr), "should be a known piece of control");
753 } else if (ptr->is_IfTrue()) {
754 IfNode* iff = ptr->in(0)->as_If();
755 BoolNode* b = iff->in(1)->isa_Bool();
756 Node* cmp = b->in(1);
757 Node* v1 = cmp->in(1);
758 Node* v2 = cmp->in(2);
759 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
760
761 // Null check of the return of append which can simply be eliminated
762 if (b->_test._test == BoolTest::ne &&
763 v2->bottom_type() == TypePtr::NULL_PTR &&
764 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
765 // NULL check of the return value of the append
766 null_check_count++;
767 if (otherproj->outcnt() == 1) {
768 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
769 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
770 ctrl_path.push(call);
771 }
772 }
773 _control.push(ptr);
774 ptr = ptr->in(0)->in(0);
775 continue;
776 }
777
778 // A test which leads to an uncommon trap which should be safe.
779 // Later this trap will be converted into a trap that restarts
780 // at the beginning.
781 if (otherproj->outcnt() == 1) {
782 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
783 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
784 // control flow leads to uct so should be ok
785 _uncommon_traps.push(call);
786 ctrl_path.push(call);
787 ptr = ptr->in(0)->in(0);
788 continue;
789 }
790 }
791
792 #ifndef PRODUCT
793 // Some unexpected control flow we don't know how to handle.
794 if (PrintOptimizeStringConcat) {
795 tty->print_cr("failing with unknown test");
796 b->dump();
797 cmp->dump();
798 v1->dump();
799 v2->dump();
800 tty->cr();
801 }
802 #endif
803 fail = true;
804 break;
805 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
806 ptr = ptr->in(0)->in(0);
807 } else if (ptr->is_Region()) {
808 Node* copy = ptr->as_Region()->is_copy();
809 if (copy != NULL) {
810 ptr = copy;
811 continue;
812 }
813 if (ptr->req() == 3 &&
814 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
815 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
816 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
817 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
818 // Simple diamond.
819 // XXX should check for possibly merging stores. simple data merges are ok.
820 ptr = ptr->in(1)->in(0)->in(0);
821 continue;
822 }
823 #ifndef PRODUCT
824 if (PrintOptimizeStringConcat) {
825 tty->print_cr("fusion would fail for region");
826 _begin->dump();
827 ptr->dump(2);
828 }
829 #endif
830 fail = true;
831 break;
832 } else {
833 // other unknown control
834 if (!fail) {
835 #ifndef PRODUCT
836 if (PrintOptimizeStringConcat) {
837 tty->print_cr("fusion would fail for");
838 _begin->dump();
839 }
840 #endif
841 fail = true;
842 }
843 #ifndef PRODUCT
844 if (PrintOptimizeStringConcat) {
845 ptr->dump();
846 }
847 #endif
848 ptr = ptr->in(0);
849 }
850 }
851 #ifndef PRODUCT
852 if (PrintOptimizeStringConcat && fail) {
853 tty->cr();
854 }
855 #endif
856 if (fail) return !fail;
857
858 // Validate that all these results produced are contained within
859 // this cluster of objects. First collect all the results produced
860 // by calls in the region.
861 _stringopts->_visited.Clear();
862 Node_List worklist;
863 Node* final_result = _end->proj_out(TypeFunc::Parms);
864 for (uint i = 0; i < _control.size(); i++) {
865 CallNode* cnode = _control.at(i)->isa_Call();
866 if (cnode != NULL) {
867 _stringopts->_visited.test_set(cnode->_idx);
868 }
869 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
870 if (result != NULL && result != final_result) {
871 worklist.push(result);
872 }
873 }
874
875 Node* last_result = NULL;
876 while (worklist.size() > 0) {
877 Node* result = worklist.pop();
878 if (_stringopts->_visited.test_set(result->_idx))
879 continue;
880 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
881 Node *use = i.get();
882 if (ctrl_path.member(use)) {
883 // already checked this
884 continue;
885 }
886 int opc = use->Opcode();
887 if (opc == Op_CmpP || opc == Op_Node) {
888 ctrl_path.push(use);
889 continue;
890 }
891 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
892 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
893 worklist.push(j.get());
894 }
895 worklist.push(use->in(1));
896 ctrl_path.push(use);
897 continue;
898 }
899 #ifndef PRODUCT
900 if (PrintOptimizeStringConcat) {
901 if (result != last_result) {
902 last_result = result;
903 tty->print_cr("extra uses for result:");
904 last_result->dump();
905 }
906 use->dump();
907 }
908 #endif
909 fail = true;
910 break;
911 }
912 }
913
914 #ifndef PRODUCT
915 if (PrintOptimizeStringConcat && !fail) {
916 ttyLocker ttyl;
917 tty->cr();
918 tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
919 _begin->jvms()->dump_spec(tty); tty->cr();
920 for (int i = 0; i < num_arguments(); i++) {
921 argument(i)->dump();
922 }
923 _control.dump();
924 tty->cr();
925 }
926 #endif
927
928 return !fail;
929 }
930
931 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
932 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
933 Node* klass_node = __ makecon(mirror_type);
934 BasicType bt = field->layout_type();
935 ciType* field_klass = field->type();
936
937 const Type *type;
938 if( bt == T_OBJECT ) {
939 if (!field->type()->is_loaded()) {
940 type = TypeInstPtr::BOTTOM;
941 } else if (field->is_constant()) {
942 // This can happen if the constant oop is non-perm.
943 ciObject* con = field->constant_value().as_object();
944 // Do not "join" in the previous type; it doesn't add value,
945 // and may yield a vacuous result if the field is of interface type.
946 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
947 assert(type != NULL, "field singleton type must be consistent");
948 return __ makecon(type);
949 } else {
950 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
951 }
952 } else {
953 type = Type::get_const_basic_type(bt);
954 }
955
956 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
957 type, T_OBJECT,
958 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())));
959 }
960
961 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
962 RegionNode *final_merge = new (C, 3) RegionNode(3);
963 kit.gvn().set_type(final_merge, Type::CONTROL);
964 Node* final_size = new (C, 3) PhiNode(final_merge, TypeInt::INT);
965 kit.gvn().set_type(final_size, TypeInt::INT);
966
967 IfNode* iff = kit.create_and_map_if(kit.control(),
968 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
969 PROB_FAIR, COUNT_UNKNOWN);
970 Node* is_min = __ IfFalse(iff);
971 final_merge->init_req(1, is_min);
972 final_size->init_req(1, __ intcon(11));
973
974 kit.set_control(__ IfTrue(iff));
975 if (kit.stopped()) {
976 final_merge->init_req(2, C->top());
977 final_size->init_req(2, C->top());
978 } else {
979
980 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
981 RegionNode *r = new (C, 3) RegionNode(3);
982 kit.gvn().set_type(r, Type::CONTROL);
983 Node *phi = new (C, 3) PhiNode(r, TypeInt::INT);
984 kit.gvn().set_type(phi, TypeInt::INT);
985 Node *size = new (C, 3) PhiNode(r, TypeInt::INT);
986 kit.gvn().set_type(size, TypeInt::INT);
987 Node* chk = __ CmpI(arg, __ intcon(0));
988 Node* p = __ Bool(chk, BoolTest::lt);
989 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
990 Node* lessthan = __ IfTrue(iff);
991 Node* greaterequal = __ IfFalse(iff);
992 r->init_req(1, lessthan);
993 phi->init_req(1, __ SubI(__ intcon(0), arg));
994 size->init_req(1, __ intcon(1));
995 r->init_req(2, greaterequal);
996 phi->init_req(2, arg);
997 size->init_req(2, __ intcon(0));
998 kit.set_control(r);
999 C->record_for_igvn(r);
1000 C->record_for_igvn(phi);
1001 C->record_for_igvn(size);
1002
1003 // for (int i=0; ; i++)
1004 // if (x <= sizeTable[i])
1005 // return i+1;
1006
1007 // Add loop predicate first.
1008 kit.add_predicate();
1009
1010 RegionNode *loop = new (C, 3) RegionNode(3);
1011 loop->init_req(1, kit.control());
1012 kit.gvn().set_type(loop, Type::CONTROL);
1013
1014 Node *index = new (C, 3) PhiNode(loop, TypeInt::INT);
1015 index->init_req(1, __ intcon(0));
1016 kit.gvn().set_type(index, TypeInt::INT);
1017 kit.set_control(loop);
1018 Node* sizeTable = fetch_static_field(kit, size_table_field);
1019
1020 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1021 C->record_for_igvn(value);
1022 Node* limit = __ CmpI(phi, value);
1023 Node* limitb = __ Bool(limit, BoolTest::le);
1024 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1025 Node* lessEqual = __ IfTrue(iff2);
1026 Node* greater = __ IfFalse(iff2);
1027
1028 loop->init_req(2, greater);
1029 index->init_req(2, __ AddI(index, __ intcon(1)));
1030
1031 kit.set_control(lessEqual);
1032 C->record_for_igvn(loop);
1033 C->record_for_igvn(index);
1034
1035 final_merge->init_req(2, kit.control());
1036 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1037 }
1038
1039 kit.set_control(final_merge);
1040 C->record_for_igvn(final_merge);
1041 C->record_for_igvn(final_size);
1042
1043 return final_size;
1044 }
1045
1046 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1047 RegionNode *final_merge = new (C, 4) RegionNode(4);
1048 kit.gvn().set_type(final_merge, Type::CONTROL);
1049 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1050 kit.gvn().set_type(final_mem, Type::MEMORY);
1051
1052 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1053 {
1054 // i == MIN_VALUE
1055 IfNode* iff = kit.create_and_map_if(kit.control(),
1056 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1057 PROB_FAIR, COUNT_UNKNOWN);
1058
1059 Node* old_mem = kit.memory(char_adr_idx);
1060
1061 kit.set_control(__ IfFalse(iff));
1062 if (kit.stopped()) {
1063 // Statically not equal to MIN_VALUE so this path is dead
1064 final_merge->init_req(3, kit.control());
1065 } else {
1066 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1067 char_array, start);
1068 final_merge->init_req(3, kit.control());
1069 final_mem->init_req(3, kit.memory(char_adr_idx));
1070 }
1071
1072 kit.set_control(__ IfTrue(iff));
1073 kit.set_memory(old_mem, char_adr_idx);
1074 }
1075
1076
1077 // Simplified version of Integer.getChars
1078
1079 // int q, r;
1080 // int charPos = index;
1081 Node* charPos = end;
1082
1083 // char sign = 0;
1084
1085 Node* i = arg;
1086 Node* sign = __ intcon(0);
1087
1088 // if (i < 0) {
1089 // sign = '-';
1090 // i = -i;
1091 // }
1092 {
1093 IfNode* iff = kit.create_and_map_if(kit.control(),
1094 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1095 PROB_FAIR, COUNT_UNKNOWN);
1096
1097 RegionNode *merge = new (C, 3) RegionNode(3);
1098 kit.gvn().set_type(merge, Type::CONTROL);
1099 i = new (C, 3) PhiNode(merge, TypeInt::INT);
1100 kit.gvn().set_type(i, TypeInt::INT);
1101 sign = new (C, 3) PhiNode(merge, TypeInt::INT);
1102 kit.gvn().set_type(sign, TypeInt::INT);
1103
1104 merge->init_req(1, __ IfTrue(iff));
1105 i->init_req(1, __ SubI(__ intcon(0), arg));
1106 sign->init_req(1, __ intcon('-'));
1107 merge->init_req(2, __ IfFalse(iff));
1108 i->init_req(2, arg);
1109 sign->init_req(2, __ intcon(0));
1110
1111 kit.set_control(merge);
1112
1113 C->record_for_igvn(merge);
1114 C->record_for_igvn(i);
1115 C->record_for_igvn(sign);
1116 }
1117
1118 // for (;;) {
1119 // q = i / 10;
1120 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1121 // buf [--charPos] = digits [r];
1122 // i = q;
1123 // if (i == 0) break;
1124 // }
1125
1126 {
1127 // Add loop predicate first.
1128 kit.add_predicate();
1129
1130 RegionNode *head = new (C, 3) RegionNode(3);
1131 head->init_req(1, kit.control());
1132 kit.gvn().set_type(head, Type::CONTROL);
1133 Node *i_phi = new (C, 3) PhiNode(head, TypeInt::INT);
1134 i_phi->init_req(1, i);
1135 kit.gvn().set_type(i_phi, TypeInt::INT);
1136 charPos = PhiNode::make(head, charPos);
1137 kit.gvn().set_type(charPos, TypeInt::INT);
1138 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1139 kit.gvn().set_type(mem, Type::MEMORY);
1140 kit.set_control(head);
1141 kit.set_memory(mem, char_adr_idx);
1142
1143 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1144 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1145 __ LShiftI(q, __ intcon(1))));
1146 Node* m1 = __ SubI(charPos, __ intcon(1));
1147 Node* ch = __ AddI(r, __ intcon('0'));
1148
1149 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1150 ch, T_CHAR, char_adr_idx);
1151
1152
1153 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1154 PROB_FAIR, COUNT_UNKNOWN);
1155 Node* ne = __ IfTrue(iff);
1156 Node* eq = __ IfFalse(iff);
1157
1158 head->init_req(2, ne);
1159 mem->init_req(2, st);
1160 i_phi->init_req(2, q);
1161 charPos->init_req(2, m1);
1162
1163 charPos = m1;
1164
1165 kit.set_control(eq);
1166 kit.set_memory(st, char_adr_idx);
1167
1168 C->record_for_igvn(head);
1169 C->record_for_igvn(mem);
1170 C->record_for_igvn(i_phi);
1171 C->record_for_igvn(charPos);
1172 }
1173
1174 {
1175 // if (sign != 0) {
1176 // buf [--charPos] = sign;
1177 // }
1178 IfNode* iff = kit.create_and_map_if(kit.control(),
1179 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1180 PROB_FAIR, COUNT_UNKNOWN);
1181
1182 final_merge->init_req(2, __ IfFalse(iff));
1183 final_mem->init_req(2, kit.memory(char_adr_idx));
1184
1185 kit.set_control(__ IfTrue(iff));
1186 if (kit.stopped()) {
1187 final_merge->init_req(1, C->top());
1188 final_mem->init_req(1, C->top());
1189 } else {
1190 Node* m1 = __ SubI(charPos, __ intcon(1));
1191 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1192 sign, T_CHAR, char_adr_idx);
1193
1194 final_merge->init_req(1, kit.control());
1195 final_mem->init_req(1, st);
1196 }
1197
1198 kit.set_control(final_merge);
1199 kit.set_memory(final_mem, char_adr_idx);
1200
1201 C->record_for_igvn(final_merge);
1202 C->record_for_igvn(final_mem);
1203 }
1204 }
1205
1206
1207 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1208 Node* string = str;
1209 Node* offset = kit.load_String_offset(kit.control(), string);
1210 Node* count = kit.load_String_length(kit.control(), string);
1211 Node* value = kit.load_String_value (kit.control(), string);
1212
1213 // copy the contents
1214 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1215 // For small constant strings just emit individual stores.
1216 // A length of 6 seems like a good space/speed tradeof.
1217 int c = count->get_int();
1218 int o = offset->get_int();
1219 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1220 ciTypeArray* value_array = t->const_oop()->as_type_array();
1221 for (int e = 0; e < c; e++) {
1222 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1223 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1224 start = __ AddI(start, __ intcon(1));
1225 }
1226 } else {
1227 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1228 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1229 Node* c = count;
1230 Node* extra = NULL;
1231 #ifdef _LP64
1232 c = __ ConvI2L(c);
1233 extra = C->top();
1234 #endif
1235 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1236 OptoRuntime::fast_arraycopy_Type(),
1237 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1238 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1239 src_ptr, dst_ptr, c, extra);
1240 start = __ AddI(start, count);
1241 }
1242 return start;
1243 }
1244
1245
1246 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1247 // Log a little info about the transformation
1248 sc->maybe_log_transform();
1249
1250 // pull the JVMState of the allocation into a SafePointNode to serve as
1251 // as a shim for the insertion of the new code.
1252 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1253 uint size = sc->begin()->req();
1254 SafePointNode* map = new (C, size) SafePointNode(size, jvms);
1255
1256 // copy the control and memory state from the final call into our
1257 // new starting state. This allows any preceeding tests to feed
1258 // into the new section of code.
1259 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1260 map->init_req(i1, sc->end()->in(i1));
1261 }
1262 // blow away old allocation arguments
1263 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1264 map->init_req(i1, C->top());
1265 }
1266 // Copy the rest of the inputs for the JVMState
1267 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1268 map->init_req(i1, sc->begin()->in(i1));
1269 }
1270 // Make sure the memory state is a MergeMem for parsing.
1271 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1272 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1273 }
1274
1275 jvms->set_map(map);
1276 map->ensure_stack(jvms, jvms->method()->max_stack());
1277
1278
1279 // disconnect all the old StringBuilder calls from the graph
1280 sc->eliminate_unneeded_control();
1281
1282 // At this point all the old work has been completely removed from
1283 // the graph and the saved JVMState exists at the point where the
1284 // final toString call used to be.
1285 GraphKit kit(jvms);
1286
1287 // There may be uncommon traps which are still using the
1288 // intermediate states and these need to be rewritten to point at
1289 // the JVMState at the beginning of the transformation.
1290 sc->convert_uncommon_traps(kit, jvms);
1291
1292 // Now insert the logic to compute the size of the string followed
1293 // by all the logic to construct array and resulting string.
1294
1295 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1296
1297 // Create a region for the overflow checks to merge into.
1298 int args = MAX2(sc->num_arguments(), 1);
1299 RegionNode* overflow = new (C, args) RegionNode(args);
1300 kit.gvn().set_type(overflow, Type::CONTROL);
1301
1302 // Create a hook node to hold onto the individual sizes since they
1303 // are need for the copying phase.
1304 Node* string_sizes = new (C, args) Node(args);
1305
1306 Node* length = __ intcon(0);
1307 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1308 Node* arg = sc->argument(argi);
1309 switch (sc->mode(argi)) {
1310 case StringConcat::IntMode: {
1311 Node* string_size = int_stringSize(kit, arg);
1312
1313 // accumulate total
1314 length = __ AddI(length, string_size);
1315
1316 // Cache this value for the use by int_toString
1317 string_sizes->init_req(argi, string_size);
1318 break;
1319 }
1320 case StringConcat::StringNullCheckMode: {
1321 const Type* type = kit.gvn().type(arg);
1322 assert(type != TypePtr::NULL_PTR, "missing check");
1323 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1324 // Null check with uncommont trap since
1325 // StringBuilder(null) throws exception.
1326 // Use special uncommon trap instead of
1327 // calling normal do_null_check().
1328 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1329 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1330 overflow->add_req(__ IfFalse(iff));
1331 Node* notnull = __ IfTrue(iff);
1332 kit.set_control(notnull); // set control for the cast_not_null
1333 arg = kit.cast_not_null(arg, false);
1334 sc->set_argument(argi, arg);
1335 }
1336 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1337 // Fallthrough to add string length.
1338 }
1339 case StringConcat::StringMode: {
1340 const Type* type = kit.gvn().type(arg);
1341 if (type == TypePtr::NULL_PTR) {
1342 // replace the argument with the null checked version
1343 arg = null_string;
1344 sc->set_argument(argi, arg);
1345 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1346 // s = s != null ? s : "null";
1347 // length = length + (s.count - s.offset);
1348 RegionNode *r = new (C, 3) RegionNode(3);
1349 kit.gvn().set_type(r, Type::CONTROL);
1350 Node *phi = new (C, 3) PhiNode(r, type);
1351 kit.gvn().set_type(phi, phi->bottom_type());
1352 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1353 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1354 Node* notnull = __ IfTrue(iff);
1355 Node* isnull = __ IfFalse(iff);
1356 kit.set_control(notnull); // set control for the cast_not_null
1357 r->init_req(1, notnull);
1358 phi->init_req(1, kit.cast_not_null(arg, false));
1359 r->init_req(2, isnull);
1360 phi->init_req(2, null_string);
1361 kit.set_control(r);
1362 C->record_for_igvn(r);
1363 C->record_for_igvn(phi);
1364 // replace the argument with the null checked version
1365 arg = phi;
1366 sc->set_argument(argi, arg);
1367 }
1368
1369 Node* count = kit.load_String_length(kit.control(), arg);
1370
1371 length = __ AddI(length, count);
1372 string_sizes->init_req(argi, NULL);
1373 break;
1374 }
1375 case StringConcat::CharMode: {
1376 // one character only
1377 length = __ AddI(length, __ intcon(1));
1378 break;
1379 }
1380 default:
1381 ShouldNotReachHere();
1382 }
1383 if (argi > 0) {
1384 // Check that the sum hasn't overflowed
1385 IfNode* iff = kit.create_and_map_if(kit.control(),
1386 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1387 PROB_MIN, COUNT_UNKNOWN);
1388 kit.set_control(__ IfFalse(iff));
1389 overflow->set_req(argi, __ IfTrue(iff));
1390 }
1391 }
1392
1393 {
1394 // Hook
1395 PreserveJVMState pjvms(&kit);
1396 kit.set_control(overflow);
1397 C->record_for_igvn(overflow);
1398 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1399 Deoptimization::Action_make_not_entrant);
1400 }
1401
1402 // length now contains the number of characters needed for the
1403 // char[] so create a new AllocateArray for the char[]
1404 Node* char_array = NULL;
1405 {
1406 PreserveReexecuteState preexecs(&kit);
1407 // The original jvms is for an allocation of either a String or
1408 // StringBuffer so no stack adjustment is necessary for proper
1409 // reexecution. If we deoptimize in the slow path the bytecode
1410 // will be reexecuted and the char[] allocation will be thrown away.
1411 kit.jvms()->set_should_reexecute(true);
1412 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1413 length, 1);
1414 }
1415
1416 // Mark the allocation so that zeroing is skipped since the code
1417 // below will overwrite the entire array
1418 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1419 char_alloc->maybe_set_complete(_gvn);
1420
1421 // Now copy the string representations into the final char[]
1422 Node* start = __ intcon(0);
1423 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1424 Node* arg = sc->argument(argi);
1425 switch (sc->mode(argi)) {
1426 case StringConcat::IntMode: {
1427 Node* end = __ AddI(start, string_sizes->in(argi));
1428 // getChars words backwards so pass the ending point as well as the start
1429 int_getChars(kit, arg, char_array, start, end);
1430 start = end;
1431 break;
1432 }
1433 case StringConcat::StringNullCheckMode:
1434 case StringConcat::StringMode: {
1435 start = copy_string(kit, arg, char_array, start);
1436 break;
1437 }
1438 case StringConcat::CharMode: {
1439 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1440 arg, T_CHAR, char_adr_idx);
1441 start = __ AddI(start, __ intcon(1));
1442 break;
1443 }
1444 default:
1445 ShouldNotReachHere();
1446 }
1447 }
1448
1449 // If we're not reusing an existing String allocation then allocate one here.
1450 Node* result = sc->string_alloc();
1451 if (result == NULL) {
1452 PreserveReexecuteState preexecs(&kit);
1453 // The original jvms is for an allocation of either a String or
1454 // StringBuffer so no stack adjustment is necessary for proper
1455 // reexecution.
1456 kit.jvms()->set_should_reexecute(true);
1457 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1458 }
1459
1460 // Intialize the string
1461 if (java_lang_String::has_offset_field()) {
1462 kit.store_String_offset(kit.control(), result, __ intcon(0));
1463 kit.store_String_length(kit.control(), result, length);
1464 }
1465 kit.store_String_value(kit.control(), result, char_array);
1466
1467 // hook up the outgoing control and result
1468 kit.replace_call(sc->end(), result);
1469
1470 // Unhook any hook nodes
1471 string_sizes->disconnect_inputs(NULL);
1472 sc->cleanup();
1473 }