1 /*
2 * Copyright (c) 2009, 2011, 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 void push_string(Node* value) {
116 push(value, StringMode);
117 }
118 void push_string_null_check(Node* value) {
119 push(value, StringNullCheckMode);
120 }
121 void push_int(Node* value) {
122 push(value, IntMode);
123 }
124 void push_char(Node* value) {
125 push(value, CharMode);
126 }
127
128 Node* argument(int i) {
129 return _arguments->in(i);
130 }
131 void set_argument(int i, Node* value) {
132 _arguments->set_req(i, value);
133 }
134 int num_arguments() {
135 return _mode.length();
136 }
137 int mode(int i) {
138 return _mode.at(i);
139 }
140 void add_control(Node* ctrl) {
141 assert(!_control.contains(ctrl), "only push once");
142 _control.push(ctrl);
143 }
144 CallStaticJavaNode* end() { return _end; }
145 AllocateNode* begin() { return _begin; }
146 Node* string_alloc() { return _string_alloc; }
147
148 void eliminate_unneeded_control();
149 void eliminate_initialize(InitializeNode* init);
150 void eliminate_call(CallNode* call);
151
152 void maybe_log_transform() {
153 CompileLog* log = _stringopts->C->log();
154 if (log != NULL) {
155 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
156 num_arguments(),
157 _string_alloc != NULL,
158 _multiple);
159 JVMState* p = _begin->jvms();
160 while (p != NULL) {
161 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
162 p = p->caller();
163 }
164 log->tail("replace_string_concat");
165 }
166 }
167
168 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
169 for (uint u = 0; u < _uncommon_traps.size(); u++) {
170 Node* uct = _uncommon_traps.at(u);
171
172 // Build a new call using the jvms state of the allocate
173 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
174 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
175 int size = call_type->domain()->cnt();
176 const TypePtr* no_memory_effects = NULL;
177 Compile* C = _stringopts->C;
178 CallStaticJavaNode* call = new (C, size) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
179 jvms->bci(), no_memory_effects);
180 for (int e = 0; e < TypeFunc::Parms; e++) {
181 call->init_req(e, uct->in(e));
182 }
183 // Set the trap request to record intrinsic failure if this trap
184 // is taken too many times. Ideally we would handle then traps by
185 // doing the original bookkeeping in the MDO so that if it caused
186 // the code to be thrown out we could still recompile and use the
187 // optimization. Failing the uncommon traps doesn't really mean
188 // that the optimization is a bad idea but there's no other way to
189 // do the MDO updates currently.
190 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
191 Deoptimization::Action_make_not_entrant);
192 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
193 kit.add_safepoint_edges(call);
194
195 _stringopts->gvn()->transform(call);
196 C->gvn_replace_by(uct, call);
197 uct->disconnect_inputs(NULL);
198 }
199 }
200
201 void cleanup() {
202 // disconnect the hook node
203 _arguments->disconnect_inputs(NULL);
204 }
205 };
206
207
208 void StringConcat::eliminate_unneeded_control() {
209 eliminate_initialize(begin()->initialization());
210 for (uint i = 0; i < _control.size(); i++) {
211 Node* n = _control.at(i);
212 if (n->is_Call()) {
213 if (n != _end) {
214 eliminate_call(n->as_Call());
215 }
216 } else if (n->is_IfTrue()) {
217 Compile* C = _stringopts->C;
218 C->gvn_replace_by(n, n->in(0)->in(0));
219 C->gvn_replace_by(n->in(0), C->top());
220 }
221 }
222 }
223
224
225 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
226 StringConcat* result = new StringConcat(_stringopts, _end);
227 for (uint x = 0; x < _control.size(); x++) {
228 Node* n = _control.at(x);
229 if (n->is_Call()) {
230 result->_control.push(n);
231 }
232 }
233 for (uint x = 0; x < other->_control.size(); x++) {
234 Node* n = other->_control.at(x);
235 if (n->is_Call()) {
236 result->_control.push(n);
237 }
238 }
239 assert(result->_control.contains(other->_end), "what?");
240 assert(result->_control.contains(_begin), "what?");
241 for (int x = 0; x < num_arguments(); x++) {
242 if (argument(x) == arg) {
243 // replace the toString result with the all the arguments that
244 // made up the other StringConcat
245 for (int y = 0; y < other->num_arguments(); y++) {
246 result->append(other->argument(y), other->mode(y));
247 }
248 } else {
249 result->append(argument(x), mode(x));
250 }
251 }
252 result->set_allocation(other->_begin);
253 result->_multiple = true;
254 return result;
255 }
256
257
258 void StringConcat::eliminate_call(CallNode* call) {
259 Compile* C = _stringopts->C;
260 CallProjections projs;
261 call->extract_projections(&projs, false);
262 if (projs.fallthrough_catchproj != NULL) {
263 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
264 }
265 if (projs.fallthrough_memproj != NULL) {
266 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
267 }
268 if (projs.catchall_memproj != NULL) {
269 C->gvn_replace_by(projs.catchall_memproj, C->top());
270 }
271 if (projs.fallthrough_ioproj != NULL) {
272 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
273 }
274 if (projs.catchall_ioproj != NULL) {
275 C->gvn_replace_by(projs.catchall_ioproj, C->top());
276 }
277 if (projs.catchall_catchproj != NULL) {
278 // EA can't cope with the partially collapsed graph this
279 // creates so put it on the worklist to be collapsed later.
280 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
281 Node *use = i.get();
282 int opc = use->Opcode();
283 if (opc == Op_CreateEx || opc == Op_Region) {
284 _stringopts->record_dead_node(use);
285 }
286 }
287 C->gvn_replace_by(projs.catchall_catchproj, C->top());
288 }
289 if (projs.resproj != NULL) {
290 C->gvn_replace_by(projs.resproj, C->top());
291 }
292 C->gvn_replace_by(call, C->top());
293 }
294
295 void StringConcat::eliminate_initialize(InitializeNode* init) {
296 Compile* C = _stringopts->C;
297
298 // Eliminate Initialize node.
299 assert(init->outcnt() <= 2, "only a control and memory projection expected");
300 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
301 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
302 if (ctrl_proj != NULL) {
303 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
304 }
305 Node *mem_proj = init->proj_out(TypeFunc::Memory);
306 if (mem_proj != NULL) {
307 Node *mem = init->in(TypeFunc::Memory);
308 C->gvn_replace_by(mem_proj, mem);
309 }
310 C->gvn_replace_by(init, C->top());
311 init->disconnect_inputs(NULL);
312 }
313
314 Node_List PhaseStringOpts::collect_toString_calls() {
315 Node_List string_calls;
316 Node_List worklist;
317
318 _visited.Clear();
319
320 // Prime the worklist
321 for (uint i = 1; i < C->root()->len(); i++) {
322 Node* n = C->root()->in(i);
323 if (n != NULL && !_visited.test_set(n->_idx)) {
324 worklist.push(n);
325 }
326 }
327
328 while (worklist.size() > 0) {
329 Node* ctrl = worklist.pop();
330 if (ctrl->is_CallStaticJava()) {
331 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
332 ciMethod* m = csj->method();
333 if (m != NULL &&
334 (m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString ||
335 m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString)) {
336 string_calls.push(csj);
337 }
338 }
339 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
340 worklist.push(ctrl->in(0));
341 }
342 if (ctrl->is_Region()) {
343 for (uint i = 1; i < ctrl->len(); i++) {
344 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
345 worklist.push(ctrl->in(i));
346 }
347 }
348 }
349 }
350 return string_calls;
351 }
352
353
354 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
355 ciMethod* m = call->method();
356 ciSymbol* string_sig;
357 ciSymbol* int_sig;
358 ciSymbol* char_sig;
359 if (m->holder() == C->env()->StringBuilder_klass()) {
360 string_sig = ciSymbol::String_StringBuilder_signature();
361 int_sig = ciSymbol::int_StringBuilder_signature();
362 char_sig = ciSymbol::char_StringBuilder_signature();
363 } else if (m->holder() == C->env()->StringBuffer_klass()) {
364 string_sig = ciSymbol::String_StringBuffer_signature();
365 int_sig = ciSymbol::int_StringBuffer_signature();
366 char_sig = ciSymbol::char_StringBuffer_signature();
367 } else {
368 return NULL;
369 }
370 #ifndef PRODUCT
371 if (PrintOptimizeStringConcat) {
372 tty->print("considering toString call in ");
373 call->jvms()->dump_spec(tty); tty->cr();
374 }
375 #endif
376
377 StringConcat* sc = new StringConcat(this, call);
378
379 AllocateNode* alloc = NULL;
380 InitializeNode* init = NULL;
381
382 // possible opportunity for StringBuilder fusion
383 CallStaticJavaNode* cnode = call;
384 while (cnode) {
385 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
386 if (recv->is_Proj()) {
387 recv = recv->in(0);
388 }
389 cnode = recv->isa_CallStaticJava();
390 if (cnode == NULL) {
391 alloc = recv->isa_Allocate();
392 if (alloc == NULL) {
393 break;
394 }
395 // Find the constructor call
396 Node* result = alloc->result_cast();
397 if (result == NULL || !result->is_CheckCastPP()) {
398 // strange looking allocation
399 #ifndef PRODUCT
400 if (PrintOptimizeStringConcat) {
401 tty->print("giving up because allocation looks strange ");
402 alloc->jvms()->dump_spec(tty); tty->cr();
403 }
404 #endif
405 break;
406 }
407 Node* constructor = NULL;
408 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
409 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
410 if (use != NULL &&
411 use->method() != NULL &&
412 !use->method()->is_static() &&
413 use->method()->name() == ciSymbol::object_initializer_name() &&
414 use->method()->holder() == m->holder()) {
415 // Matched the constructor.
416 ciSymbol* sig = use->method()->signature()->as_symbol();
417 if (sig == ciSymbol::void_method_signature() ||
418 sig == ciSymbol::int_void_signature() ||
419 sig == ciSymbol::string_void_signature()) {
420 if (sig == ciSymbol::string_void_signature()) {
421 // StringBuilder(String) so pick this up as the first argument
422 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
423 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
424 if (type == TypePtr::NULL_PTR) {
425 // StringBuilder(null) throws exception.
426 #ifndef PRODUCT
427 if (PrintOptimizeStringConcat) {
428 tty->print("giving up because StringBuilder(null) throws exception");
429 alloc->jvms()->dump_spec(tty); tty->cr();
430 }
431 #endif
432 return NULL;
433 }
434 // StringBuilder(str) argument needs null check.
435 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
436 }
437 // The int variant takes an initial size for the backing
438 // array so just treat it like the void version.
439 constructor = use;
440 } else {
441 #ifndef PRODUCT
442 if (PrintOptimizeStringConcat) {
443 tty->print("unexpected constructor signature: %s", sig->as_utf8());
444 }
445 #endif
446 }
447 break;
448 }
449 }
450 if (constructor == NULL) {
451 // couldn't find constructor
452 #ifndef PRODUCT
453 if (PrintOptimizeStringConcat) {
454 tty->print("giving up because couldn't find constructor ");
455 alloc->jvms()->dump_spec(tty); tty->cr();
456 }
457 #endif
458 break;
459 }
460
461 // Walked all the way back and found the constructor call so see
462 // if this call converted into a direct string concatenation.
463 sc->add_control(call);
464 sc->add_control(constructor);
465 sc->add_control(alloc);
466 sc->set_allocation(alloc);
467 if (sc->validate_control_flow()) {
468 return sc;
469 } else {
470 return NULL;
471 }
472 } else if (cnode->method() == NULL) {
473 break;
474 } else if (!cnode->method()->is_static() &&
475 cnode->method()->holder() == m->holder() &&
476 cnode->method()->name() == ciSymbol::append_name() &&
477 (cnode->method()->signature()->as_symbol() == string_sig ||
478 cnode->method()->signature()->as_symbol() == char_sig ||
479 cnode->method()->signature()->as_symbol() == int_sig)) {
480 sc->add_control(cnode);
481 Node* arg = cnode->in(TypeFunc::Parms + 1);
482 if (cnode->method()->signature()->as_symbol() == int_sig) {
483 sc->push_int(arg);
484 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
485 sc->push_char(arg);
486 } else {
487 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
488 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
489 if (csj->method() != NULL &&
490 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString) {
491 sc->add_control(csj);
492 sc->push_int(csj->in(TypeFunc::Parms));
493 continue;
494 }
495 }
496 sc->push_string(arg);
497 }
498 continue;
499 } else {
500 // some unhandled signature
501 #ifndef PRODUCT
502 if (PrintOptimizeStringConcat) {
503 tty->print("giving up because encountered unexpected signature ");
504 cnode->tf()->dump(); tty->cr();
505 cnode->in(TypeFunc::Parms + 1)->dump();
506 }
507 #endif
508 break;
509 }
510 }
511 return NULL;
512 }
513
514
515 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
516 Phase(StringOpts),
517 _gvn(gvn),
518 _visited(Thread::current()->resource_area()) {
519
520 assert(OptimizeStringConcat, "shouldn't be here");
521
522 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
523 ciSymbol::make("[I"), true);
524 if (size_table_field == NULL) {
525 // Something wrong so give up.
526 assert(false, "why can't we find Integer.sizeTable?");
527 return;
528 }
529
530 // Collect the types needed to talk about the various slices of memory
531 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
532 false, NULL, 0);
533
534 const TypePtr* value_field_type = string_type->add_offset(java_lang_String::value_offset_in_bytes());
535 const TypePtr* offset_field_type = string_type->add_offset(java_lang_String::offset_offset_in_bytes());
536 const TypePtr* count_field_type = string_type->add_offset(java_lang_String::count_offset_in_bytes());
537
538 value_field_idx = C->get_alias_index(value_field_type);
539 count_field_idx = C->get_alias_index(count_field_type);
540 offset_field_idx = C->get_alias_index(offset_field_type);
541 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
542
543 // For each locally allocated StringBuffer see if the usages can be
544 // collapsed into a single String construction.
545
546 // Run through the list of allocation looking for SB.toString to see
547 // if it's possible to fuse the usage of the SB into a single String
548 // construction.
549 GrowableArray<StringConcat*> concats;
550 Node_List toStrings = collect_toString_calls();
551 while (toStrings.size() > 0) {
552 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
553 if (sc != NULL) {
554 concats.push(sc);
555 }
556 }
557
558 // try to coalesce separate concats
559 restart:
560 for (int c = 0; c < concats.length(); c++) {
561 StringConcat* sc = concats.at(c);
562 for (int i = 0; i < sc->num_arguments(); i++) {
563 Node* arg = sc->argument(i);
564 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
565 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
566 if (csj->method() != NULL &&
567 (csj->method()->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
568 csj->method()->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
569 for (int o = 0; o < concats.length(); o++) {
570 if (c == o) continue;
571 StringConcat* other = concats.at(o);
572 if (other->end() == csj) {
573 #ifndef PRODUCT
574 if (PrintOptimizeStringConcat) {
575 tty->print_cr("considering stacked concats");
576 }
577 #endif
578
579 StringConcat* merged = sc->merge(other, arg);
580 if (merged->validate_control_flow()) {
581 #ifndef PRODUCT
582 if (PrintOptimizeStringConcat) {
583 tty->print_cr("stacking would succeed");
584 }
585 #endif
586 if (c < o) {
587 concats.remove_at(o);
588 concats.at_put(c, merged);
589 } else {
590 concats.remove_at(c);
591 concats.at_put(o, merged);
592 }
593 goto restart;
594 } else {
595 #ifndef PRODUCT
596 if (PrintOptimizeStringConcat) {
597 tty->print_cr("stacking would fail");
598 }
599 #endif
600 }
601 }
602 }
603 }
604 }
605 }
606 }
607
608
609 for (int c = 0; c < concats.length(); c++) {
610 StringConcat* sc = concats.at(c);
611 replace_string_concat(sc);
612 }
613
614 remove_dead_nodes();
615 }
616
617 void PhaseStringOpts::record_dead_node(Node* dead) {
618 dead_worklist.push(dead);
619 }
620
621 void PhaseStringOpts::remove_dead_nodes() {
622 // Delete any dead nodes to make things clean enough that escape
623 // analysis doesn't get unhappy.
624 while (dead_worklist.size() > 0) {
625 Node* use = dead_worklist.pop();
626 int opc = use->Opcode();
627 switch (opc) {
628 case Op_Region: {
629 uint i = 1;
630 for (i = 1; i < use->req(); i++) {
631 if (use->in(i) != C->top()) {
632 break;
633 }
634 }
635 if (i >= use->req()) {
636 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
637 Node* m = i.get();
638 if (m->is_Phi()) {
639 dead_worklist.push(m);
640 }
641 }
642 C->gvn_replace_by(use, C->top());
643 }
644 break;
645 }
646 case Op_AddP:
647 case Op_CreateEx: {
648 // Recurisvely clean up references to CreateEx so EA doesn't
649 // get unhappy about the partially collapsed graph.
650 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
651 Node* m = i.get();
652 if (m->is_AddP()) {
653 dead_worklist.push(m);
654 }
655 }
656 C->gvn_replace_by(use, C->top());
657 break;
658 }
659 case Op_Phi:
660 if (use->in(0) == C->top()) {
661 C->gvn_replace_by(use, C->top());
662 }
663 break;
664 }
665 }
666 }
667
668
669 bool StringConcat::validate_control_flow() {
670 // We found all the calls and arguments now lets see if it's
671 // safe to transform the graph as we would expect.
672
673 // Check to see if this resulted in too many uncommon traps previously
674 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
675 Deoptimization::Reason_intrinsic)) {
676 return false;
677 }
678
679 // Walk backwards over the control flow from toString to the
680 // allocation and make sure all the control flow is ok. This
681 // means it's either going to be eliminated once the calls are
682 // removed or it can safely be transformed into an uncommon
683 // trap.
684
685 int null_check_count = 0;
686 Unique_Node_List ctrl_path;
687
688 assert(_control.contains(_begin), "missing");
689 assert(_control.contains(_end), "missing");
690
691 // Collect the nodes that we know about and will eliminate into ctrl_path
692 for (uint i = 0; i < _control.size(); i++) {
693 // Push the call and it's control projection
694 Node* n = _control.at(i);
695 if (n->is_Allocate()) {
696 AllocateNode* an = n->as_Allocate();
697 InitializeNode* init = an->initialization();
698 ctrl_path.push(init);
699 ctrl_path.push(init->as_Multi()->proj_out(0));
700 }
701 if (n->is_Call()) {
702 CallNode* cn = n->as_Call();
703 ctrl_path.push(cn);
704 ctrl_path.push(cn->proj_out(0));
705 ctrl_path.push(cn->proj_out(0)->unique_out());
706 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
707 } else {
708 ShouldNotReachHere();
709 }
710 }
711
712 // Skip backwards through the control checking for unexpected contro flow
713 Node* ptr = _end;
714 bool fail = false;
715 while (ptr != _begin) {
716 if (ptr->is_Call() && ctrl_path.member(ptr)) {
717 ptr = ptr->in(0);
718 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
719 ptr = ptr->in(0)->in(0)->in(0);
720 assert(ctrl_path.member(ptr), "should be a known piece of control");
721 } else if (ptr->is_IfTrue()) {
722 IfNode* iff = ptr->in(0)->as_If();
723 BoolNode* b = iff->in(1)->isa_Bool();
724 Node* cmp = b->in(1);
725 Node* v1 = cmp->in(1);
726 Node* v2 = cmp->in(2);
727 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
728
729 // Null check of the return of append which can simply be eliminated
730 if (b->_test._test == BoolTest::ne &&
731 v2->bottom_type() == TypePtr::NULL_PTR &&
732 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
733 // NULL check of the return value of the append
734 null_check_count++;
735 if (otherproj->outcnt() == 1) {
736 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
737 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
738 ctrl_path.push(call);
739 }
740 }
741 _control.push(ptr);
742 ptr = ptr->in(0)->in(0);
743 continue;
744 }
745
746 // A test which leads to an uncommon trap which should be safe.
747 // Later this trap will be converted into a trap that restarts
748 // at the beginning.
749 if (otherproj->outcnt() == 1) {
750 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
751 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
752 // control flow leads to uct so should be ok
753 _uncommon_traps.push(call);
754 ctrl_path.push(call);
755 ptr = ptr->in(0)->in(0);
756 continue;
757 }
758 }
759
760 #ifndef PRODUCT
761 // Some unexpected control flow we don't know how to handle.
762 if (PrintOptimizeStringConcat) {
763 tty->print_cr("failing with unknown test");
764 b->dump();
765 cmp->dump();
766 v1->dump();
767 v2->dump();
768 tty->cr();
769 }
770 #endif
771 fail = true;
772 break;
773 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
774 ptr = ptr->in(0)->in(0);
775 } else if (ptr->is_Region()) {
776 Node* copy = ptr->as_Region()->is_copy();
777 if (copy != NULL) {
778 ptr = copy;
779 continue;
780 }
781 if (ptr->req() == 3 &&
782 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
783 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
784 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
785 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
786 // Simple diamond.
787 // XXX should check for possibly merging stores. simple data merges are ok.
788 ptr = ptr->in(1)->in(0)->in(0);
789 continue;
790 }
791 #ifndef PRODUCT
792 if (PrintOptimizeStringConcat) {
793 tty->print_cr("fusion would fail for region");
794 _begin->dump();
795 ptr->dump(2);
796 }
797 #endif
798 fail = true;
799 break;
800 } else {
801 // other unknown control
802 if (!fail) {
803 #ifndef PRODUCT
804 if (PrintOptimizeStringConcat) {
805 tty->print_cr("fusion would fail for");
806 _begin->dump();
807 }
808 #endif
809 fail = true;
810 }
811 #ifndef PRODUCT
812 if (PrintOptimizeStringConcat) {
813 ptr->dump();
814 }
815 #endif
816 ptr = ptr->in(0);
817 }
818 }
819 #ifndef PRODUCT
820 if (PrintOptimizeStringConcat && fail) {
821 tty->cr();
822 }
823 #endif
824 if (fail) return !fail;
825
826 // Validate that all these results produced are contained within
827 // this cluster of objects. First collect all the results produced
828 // by calls in the region.
829 _stringopts->_visited.Clear();
830 Node_List worklist;
831 Node* final_result = _end->proj_out(TypeFunc::Parms);
832 for (uint i = 0; i < _control.size(); i++) {
833 CallNode* cnode = _control.at(i)->isa_Call();
834 if (cnode != NULL) {
835 _stringopts->_visited.test_set(cnode->_idx);
836 }
837 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
838 if (result != NULL && result != final_result) {
839 worklist.push(result);
840 }
841 }
842
843 Node* last_result = NULL;
844 while (worklist.size() > 0) {
845 Node* result = worklist.pop();
846 if (_stringopts->_visited.test_set(result->_idx))
847 continue;
848 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
849 Node *use = i.get();
850 if (ctrl_path.member(use)) {
851 // already checked this
852 continue;
853 }
854 int opc = use->Opcode();
855 if (opc == Op_CmpP || opc == Op_Node) {
856 ctrl_path.push(use);
857 continue;
858 }
859 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
860 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
861 worklist.push(j.get());
862 }
863 worklist.push(use->in(1));
864 ctrl_path.push(use);
865 continue;
866 }
867 #ifndef PRODUCT
868 if (PrintOptimizeStringConcat) {
869 if (result != last_result) {
870 last_result = result;
871 tty->print_cr("extra uses for result:");
872 last_result->dump();
873 }
874 use->dump();
875 }
876 #endif
877 fail = true;
878 break;
879 }
880 }
881
882 #ifndef PRODUCT
883 if (PrintOptimizeStringConcat && !fail) {
884 ttyLocker ttyl;
885 tty->cr();
886 tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
887 _begin->jvms()->dump_spec(tty); tty->cr();
888 for (int i = 0; i < num_arguments(); i++) {
889 argument(i)->dump();
890 }
891 _control.dump();
892 tty->cr();
893 }
894 #endif
895
896 return !fail;
897 }
898
899 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
900 const TypeKlassPtr* klass_type = TypeKlassPtr::make(field->holder());
901 Node* klass_node = __ makecon(klass_type);
902 BasicType bt = field->layout_type();
903 ciType* field_klass = field->type();
904
905 const Type *type;
906 if( bt == T_OBJECT ) {
907 if (!field->type()->is_loaded()) {
908 type = TypeInstPtr::BOTTOM;
909 } else if (field->is_constant()) {
910 // This can happen if the constant oop is non-perm.
911 ciObject* con = field->constant_value().as_object();
912 // Do not "join" in the previous type; it doesn't add value,
913 // and may yield a vacuous result if the field is of interface type.
914 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
915 assert(type != NULL, "field singleton type must be consistent");
916 } else {
917 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
918 }
919 } else {
920 type = Type::get_const_basic_type(bt);
921 }
922
923 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
924 type, T_OBJECT,
925 C->get_alias_index(klass_type->add_offset(field->offset_in_bytes())));
926 }
927
928 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
929 RegionNode *final_merge = new (C, 3) RegionNode(3);
930 kit.gvn().set_type(final_merge, Type::CONTROL);
931 Node* final_size = new (C, 3) PhiNode(final_merge, TypeInt::INT);
932 kit.gvn().set_type(final_size, TypeInt::INT);
933
934 IfNode* iff = kit.create_and_map_if(kit.control(),
935 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
936 PROB_FAIR, COUNT_UNKNOWN);
937 Node* is_min = __ IfFalse(iff);
938 final_merge->init_req(1, is_min);
939 final_size->init_req(1, __ intcon(11));
940
941 kit.set_control(__ IfTrue(iff));
942 if (kit.stopped()) {
943 final_merge->init_req(2, C->top());
944 final_size->init_req(2, C->top());
945 } else {
946
947 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
948 RegionNode *r = new (C, 3) RegionNode(3);
949 kit.gvn().set_type(r, Type::CONTROL);
950 Node *phi = new (C, 3) PhiNode(r, TypeInt::INT);
951 kit.gvn().set_type(phi, TypeInt::INT);
952 Node *size = new (C, 3) PhiNode(r, TypeInt::INT);
953 kit.gvn().set_type(size, TypeInt::INT);
954 Node* chk = __ CmpI(arg, __ intcon(0));
955 Node* p = __ Bool(chk, BoolTest::lt);
956 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
957 Node* lessthan = __ IfTrue(iff);
958 Node* greaterequal = __ IfFalse(iff);
959 r->init_req(1, lessthan);
960 phi->init_req(1, __ SubI(__ intcon(0), arg));
961 size->init_req(1, __ intcon(1));
962 r->init_req(2, greaterequal);
963 phi->init_req(2, arg);
964 size->init_req(2, __ intcon(0));
965 kit.set_control(r);
966 C->record_for_igvn(r);
967 C->record_for_igvn(phi);
968 C->record_for_igvn(size);
969
970 // for (int i=0; ; i++)
971 // if (x <= sizeTable[i])
972 // return i+1;
973
974 // Add loop predicate first.
975 kit.add_predicate();
976
977 RegionNode *loop = new (C, 3) RegionNode(3);
978 loop->init_req(1, kit.control());
979 kit.gvn().set_type(loop, Type::CONTROL);
980
981 Node *index = new (C, 3) PhiNode(loop, TypeInt::INT);
982 index->init_req(1, __ intcon(0));
983 kit.gvn().set_type(index, TypeInt::INT);
984 kit.set_control(loop);
985 Node* sizeTable = fetch_static_field(kit, size_table_field);
986
987 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
988 C->record_for_igvn(value);
989 Node* limit = __ CmpI(phi, value);
990 Node* limitb = __ Bool(limit, BoolTest::le);
991 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
992 Node* lessEqual = __ IfTrue(iff2);
993 Node* greater = __ IfFalse(iff2);
994
995 loop->init_req(2, greater);
996 index->init_req(2, __ AddI(index, __ intcon(1)));
997
998 kit.set_control(lessEqual);
999 C->record_for_igvn(loop);
1000 C->record_for_igvn(index);
1001
1002 final_merge->init_req(2, kit.control());
1003 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1004 }
1005
1006 kit.set_control(final_merge);
1007 C->record_for_igvn(final_merge);
1008 C->record_for_igvn(final_size);
1009
1010 return final_size;
1011 }
1012
1013 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1014 RegionNode *final_merge = new (C, 4) RegionNode(4);
1015 kit.gvn().set_type(final_merge, Type::CONTROL);
1016 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1017 kit.gvn().set_type(final_mem, Type::MEMORY);
1018
1019 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1020 {
1021 // i == MIN_VALUE
1022 IfNode* iff = kit.create_and_map_if(kit.control(),
1023 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1024 PROB_FAIR, COUNT_UNKNOWN);
1025
1026 Node* old_mem = kit.memory(char_adr_idx);
1027
1028 kit.set_control(__ IfFalse(iff));
1029 if (kit.stopped()) {
1030 // Statically not equal to MIN_VALUE so this path is dead
1031 final_merge->init_req(3, kit.control());
1032 } else {
1033 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1034 char_array, start);
1035 final_merge->init_req(3, kit.control());
1036 final_mem->init_req(3, kit.memory(char_adr_idx));
1037 }
1038
1039 kit.set_control(__ IfTrue(iff));
1040 kit.set_memory(old_mem, char_adr_idx);
1041 }
1042
1043
1044 // Simplified version of Integer.getChars
1045
1046 // int q, r;
1047 // int charPos = index;
1048 Node* charPos = end;
1049
1050 // char sign = 0;
1051
1052 Node* i = arg;
1053 Node* sign = __ intcon(0);
1054
1055 // if (i < 0) {
1056 // sign = '-';
1057 // i = -i;
1058 // }
1059 {
1060 IfNode* iff = kit.create_and_map_if(kit.control(),
1061 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1062 PROB_FAIR, COUNT_UNKNOWN);
1063
1064 RegionNode *merge = new (C, 3) RegionNode(3);
1065 kit.gvn().set_type(merge, Type::CONTROL);
1066 i = new (C, 3) PhiNode(merge, TypeInt::INT);
1067 kit.gvn().set_type(i, TypeInt::INT);
1068 sign = new (C, 3) PhiNode(merge, TypeInt::INT);
1069 kit.gvn().set_type(sign, TypeInt::INT);
1070
1071 merge->init_req(1, __ IfTrue(iff));
1072 i->init_req(1, __ SubI(__ intcon(0), arg));
1073 sign->init_req(1, __ intcon('-'));
1074 merge->init_req(2, __ IfFalse(iff));
1075 i->init_req(2, arg);
1076 sign->init_req(2, __ intcon(0));
1077
1078 kit.set_control(merge);
1079
1080 C->record_for_igvn(merge);
1081 C->record_for_igvn(i);
1082 C->record_for_igvn(sign);
1083 }
1084
1085 // for (;;) {
1086 // q = i / 10;
1087 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1088 // buf [--charPos] = digits [r];
1089 // i = q;
1090 // if (i == 0) break;
1091 // }
1092
1093 {
1094 // Add loop predicate first.
1095 kit.add_predicate();
1096
1097 RegionNode *head = new (C, 3) RegionNode(3);
1098 head->init_req(1, kit.control());
1099 kit.gvn().set_type(head, Type::CONTROL);
1100 Node *i_phi = new (C, 3) PhiNode(head, TypeInt::INT);
1101 i_phi->init_req(1, i);
1102 kit.gvn().set_type(i_phi, TypeInt::INT);
1103 charPos = PhiNode::make(head, charPos);
1104 kit.gvn().set_type(charPos, TypeInt::INT);
1105 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1106 kit.gvn().set_type(mem, Type::MEMORY);
1107 kit.set_control(head);
1108 kit.set_memory(mem, char_adr_idx);
1109
1110 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1111 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1112 __ LShiftI(q, __ intcon(1))));
1113 Node* m1 = __ SubI(charPos, __ intcon(1));
1114 Node* ch = __ AddI(r, __ intcon('0'));
1115
1116 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1117 ch, T_CHAR, char_adr_idx);
1118
1119
1120 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1121 PROB_FAIR, COUNT_UNKNOWN);
1122 Node* ne = __ IfTrue(iff);
1123 Node* eq = __ IfFalse(iff);
1124
1125 head->init_req(2, ne);
1126 mem->init_req(2, st);
1127 i_phi->init_req(2, q);
1128 charPos->init_req(2, m1);
1129
1130 charPos = m1;
1131
1132 kit.set_control(eq);
1133 kit.set_memory(st, char_adr_idx);
1134
1135 C->record_for_igvn(head);
1136 C->record_for_igvn(mem);
1137 C->record_for_igvn(i_phi);
1138 C->record_for_igvn(charPos);
1139 }
1140
1141 {
1142 // if (sign != 0) {
1143 // buf [--charPos] = sign;
1144 // }
1145 IfNode* iff = kit.create_and_map_if(kit.control(),
1146 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1147 PROB_FAIR, COUNT_UNKNOWN);
1148
1149 final_merge->init_req(2, __ IfFalse(iff));
1150 final_mem->init_req(2, kit.memory(char_adr_idx));
1151
1152 kit.set_control(__ IfTrue(iff));
1153 if (kit.stopped()) {
1154 final_merge->init_req(1, C->top());
1155 final_mem->init_req(1, C->top());
1156 } else {
1157 Node* m1 = __ SubI(charPos, __ intcon(1));
1158 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1159 sign, T_CHAR, char_adr_idx);
1160
1161 final_merge->init_req(1, kit.control());
1162 final_mem->init_req(1, st);
1163 }
1164
1165 kit.set_control(final_merge);
1166 kit.set_memory(final_mem, char_adr_idx);
1167
1168 C->record_for_igvn(final_merge);
1169 C->record_for_igvn(final_mem);
1170 }
1171 }
1172
1173
1174 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1175 Node* string = str;
1176 Node* offset = kit.make_load(kit.control(),
1177 kit.basic_plus_adr(string, string, java_lang_String::offset_offset_in_bytes()),
1178 TypeInt::INT, T_INT, offset_field_idx);
1179 Node* count = kit.make_load(kit.control(),
1180 kit.basic_plus_adr(string, string, java_lang_String::count_offset_in_bytes()),
1181 TypeInt::INT, T_INT, count_field_idx);
1182 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
1183 TypeAry::make(TypeInt::CHAR,TypeInt::POS),
1184 ciTypeArrayKlass::make(T_CHAR), true, 0);
1185 Node* value = kit.make_load(kit.control(),
1186 kit.basic_plus_adr(string, string, java_lang_String::value_offset_in_bytes()),
1187 value_type, T_OBJECT, value_field_idx);
1188
1189 // copy the contents
1190 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1191 // For small constant strings just emit individual stores.
1192 // A length of 6 seems like a good space/speed tradeof.
1193 int c = count->get_int();
1194 int o = offset->get_int();
1195 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1196 ciTypeArray* value_array = t->const_oop()->as_type_array();
1197 for (int e = 0; e < c; e++) {
1198 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1199 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1200 start = __ AddI(start, __ intcon(1));
1201 }
1202 } else {
1203 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1204 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1205 Node* c = count;
1206 Node* extra = NULL;
1207 #ifdef _LP64
1208 c = __ ConvI2L(c);
1209 extra = C->top();
1210 #endif
1211 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1212 OptoRuntime::fast_arraycopy_Type(),
1213 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1214 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1215 src_ptr, dst_ptr, c, extra);
1216 start = __ AddI(start, count);
1217 }
1218 return start;
1219 }
1220
1221
1222 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1223 // Log a little info about the transformation
1224 sc->maybe_log_transform();
1225
1226 // pull the JVMState of the allocation into a SafePointNode to serve as
1227 // as a shim for the insertion of the new code.
1228 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1229 uint size = sc->begin()->req();
1230 SafePointNode* map = new (C, size) SafePointNode(size, jvms);
1231
1232 // copy the control and memory state from the final call into our
1233 // new starting state. This allows any preceeding tests to feed
1234 // into the new section of code.
1235 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1236 map->init_req(i1, sc->end()->in(i1));
1237 }
1238 // blow away old allocation arguments
1239 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1240 map->init_req(i1, C->top());
1241 }
1242 // Copy the rest of the inputs for the JVMState
1243 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1244 map->init_req(i1, sc->begin()->in(i1));
1245 }
1246 // Make sure the memory state is a MergeMem for parsing.
1247 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1248 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1249 }
1250
1251 jvms->set_map(map);
1252 map->ensure_stack(jvms, jvms->method()->max_stack());
1253
1254
1255 // disconnect all the old StringBuilder calls from the graph
1256 sc->eliminate_unneeded_control();
1257
1258 // At this point all the old work has been completely removed from
1259 // the graph and the saved JVMState exists at the point where the
1260 // final toString call used to be.
1261 GraphKit kit(jvms);
1262
1263 // There may be uncommon traps which are still using the
1264 // intermediate states and these need to be rewritten to point at
1265 // the JVMState at the beginning of the transformation.
1266 sc->convert_uncommon_traps(kit, jvms);
1267
1268 // Now insert the logic to compute the size of the string followed
1269 // by all the logic to construct array and resulting string.
1270
1271 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1272
1273 // Create a region for the overflow checks to merge into.
1274 int args = MAX2(sc->num_arguments(), 1);
1275 RegionNode* overflow = new (C, args) RegionNode(args);
1276 kit.gvn().set_type(overflow, Type::CONTROL);
1277
1278 // Create a hook node to hold onto the individual sizes since they
1279 // are need for the copying phase.
1280 Node* string_sizes = new (C, args) Node(args);
1281
1282 Node* length = __ intcon(0);
1283 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1284 Node* arg = sc->argument(argi);
1285 switch (sc->mode(argi)) {
1286 case StringConcat::IntMode: {
1287 Node* string_size = int_stringSize(kit, arg);
1288
1289 // accumulate total
1290 length = __ AddI(length, string_size);
1291
1292 // Cache this value for the use by int_toString
1293 string_sizes->init_req(argi, string_size);
1294 break;
1295 }
1296 case StringConcat::StringNullCheckMode: {
1297 const Type* type = kit.gvn().type(arg);
1298 assert(type != TypePtr::NULL_PTR, "missing check");
1299 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1300 // Null check with uncommont trap since
1301 // StringBuilder(null) throws exception.
1302 // Use special uncommon trap instead of
1303 // calling normal do_null_check().
1304 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1305 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1306 overflow->add_req(__ IfFalse(iff));
1307 Node* notnull = __ IfTrue(iff);
1308 kit.set_control(notnull); // set control for the cast_not_null
1309 arg = kit.cast_not_null(arg, false);
1310 sc->set_argument(argi, arg);
1311 }
1312 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1313 // Fallthrough to add string length.
1314 }
1315 case StringConcat::StringMode: {
1316 const Type* type = kit.gvn().type(arg);
1317 if (type == TypePtr::NULL_PTR) {
1318 // replace the argument with the null checked version
1319 arg = null_string;
1320 sc->set_argument(argi, arg);
1321 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1322 // s = s != null ? s : "null";
1323 // length = length + (s.count - s.offset);
1324 RegionNode *r = new (C, 3) RegionNode(3);
1325 kit.gvn().set_type(r, Type::CONTROL);
1326 Node *phi = new (C, 3) PhiNode(r, type);
1327 kit.gvn().set_type(phi, phi->bottom_type());
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 Node* notnull = __ IfTrue(iff);
1331 Node* isnull = __ IfFalse(iff);
1332 kit.set_control(notnull); // set control for the cast_not_null
1333 r->init_req(1, notnull);
1334 phi->init_req(1, kit.cast_not_null(arg, false));
1335 r->init_req(2, isnull);
1336 phi->init_req(2, null_string);
1337 kit.set_control(r);
1338 C->record_for_igvn(r);
1339 C->record_for_igvn(phi);
1340 // replace the argument with the null checked version
1341 arg = phi;
1342 sc->set_argument(argi, arg);
1343 }
1344 // Node* offset = kit.make_load(NULL, kit.basic_plus_adr(arg, arg, offset_offset),
1345 // TypeInt::INT, T_INT, offset_field_idx);
1346 Node* count = kit.make_load(kit.control(), kit.basic_plus_adr(arg, arg, java_lang_String::count_offset_in_bytes()),
1347 TypeInt::INT, T_INT, count_field_idx);
1348 length = __ AddI(length, count);
1349 string_sizes->init_req(argi, NULL);
1350 break;
1351 }
1352 case StringConcat::CharMode: {
1353 // one character only
1354 length = __ AddI(length, __ intcon(1));
1355 break;
1356 }
1357 default:
1358 ShouldNotReachHere();
1359 }
1360 if (argi > 0) {
1361 // Check that the sum hasn't overflowed
1362 IfNode* iff = kit.create_and_map_if(kit.control(),
1363 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1364 PROB_MIN, COUNT_UNKNOWN);
1365 kit.set_control(__ IfFalse(iff));
1366 overflow->set_req(argi, __ IfTrue(iff));
1367 }
1368 }
1369
1370 {
1371 // Hook
1372 PreserveJVMState pjvms(&kit);
1373 kit.set_control(overflow);
1374 C->record_for_igvn(overflow);
1375 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1376 Deoptimization::Action_make_not_entrant);
1377 }
1378
1379 // length now contains the number of characters needed for the
1380 // char[] so create a new AllocateArray for the char[]
1381 Node* char_array = NULL;
1382 {
1383 PreserveReexecuteState preexecs(&kit);
1384 // The original jvms is for an allocation of either a String or
1385 // StringBuffer so no stack adjustment is necessary for proper
1386 // reexecution. If we deoptimize in the slow path the bytecode
1387 // will be reexecuted and the char[] allocation will be thrown away.
1388 kit.jvms()->set_should_reexecute(true);
1389 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1390 length, 1);
1391 }
1392
1393 // Mark the allocation so that zeroing is skipped since the code
1394 // below will overwrite the entire array
1395 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1396 char_alloc->maybe_set_complete(_gvn);
1397
1398 // Now copy the string representations into the final char[]
1399 Node* start = __ intcon(0);
1400 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1401 Node* arg = sc->argument(argi);
1402 switch (sc->mode(argi)) {
1403 case StringConcat::IntMode: {
1404 Node* end = __ AddI(start, string_sizes->in(argi));
1405 // getChars words backwards so pass the ending point as well as the start
1406 int_getChars(kit, arg, char_array, start, end);
1407 start = end;
1408 break;
1409 }
1410 case StringConcat::StringNullCheckMode:
1411 case StringConcat::StringMode: {
1412 start = copy_string(kit, arg, char_array, start);
1413 break;
1414 }
1415 case StringConcat::CharMode: {
1416 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1417 arg, T_CHAR, char_adr_idx);
1418 start = __ AddI(start, __ intcon(1));
1419 break;
1420 }
1421 default:
1422 ShouldNotReachHere();
1423 }
1424 }
1425
1426 // If we're not reusing an existing String allocation then allocate one here.
1427 Node* result = sc->string_alloc();
1428 if (result == NULL) {
1429 PreserveReexecuteState preexecs(&kit);
1430 // The original jvms is for an allocation of either a String or
1431 // StringBuffer so no stack adjustment is necessary for proper
1432 // reexecution.
1433 kit.jvms()->set_should_reexecute(true);
1434 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1435 }
1436
1437 // Intialize the string
1438 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::offset_offset_in_bytes()),
1439 __ intcon(0), T_INT, offset_field_idx);
1440 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::count_offset_in_bytes()),
1441 length, T_INT, count_field_idx);
1442 kit.store_to_memory(kit.control(), kit.basic_plus_adr(result, java_lang_String::value_offset_in_bytes()),
1443 char_array, T_OBJECT, value_field_idx);
1444
1445 // hook up the outgoing control and result
1446 kit.replace_call(sc->end(), result);
1447
1448 // Unhook any hook nodes
1449 string_sizes->disconnect_inputs(NULL);
1450 sc->cleanup();
1451 }