1 /*
2 * Copyright (c) 2009, 2018, 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 #include "runtime/sharedRuntime.hpp"
38 #include "utilities/macros.hpp"
39 #if INCLUDE_SHENANDOAHGC
40 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
41 #endif
42
43 #define __ kit.
44
45 class StringConcat : public ResourceObj {
46 private:
47 PhaseStringOpts* _stringopts;
48 Node* _string_alloc;
49 AllocateNode* _begin; // The allocation the begins the pattern
50 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
51 // SB.toString or or String.<init>(SB.toString)
52 bool _multiple; // indicates this is a fusion of two or more
53 // separate StringBuilders
54
55 Node* _arguments; // The list of arguments to be concatenated
56 GrowableArray<int> _mode; // into a String along with a mode flag
57 // indicating how to treat the value.
58 Node_List _constructors; // List of constructors (many in case of stacked concat)
59 Node_List _control; // List of control nodes that will be deleted
60 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
61 // to restart at the initial JVMState.
62
63 public:
64 // Mode for converting arguments to Strings
65 enum {
66 StringMode,
67 IntMode,
68 CharMode,
69 StringNullCheckMode
70 };
71
72 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
73 _stringopts(stringopts),
74 _string_alloc(NULL),
75 _begin(NULL),
76 _end(end),
77 _multiple(false) {
78 _arguments = new Node(1);
79 _arguments->del_req(0);
80 }
81
82 bool validate_mem_flow();
83 bool validate_control_flow();
84
85 void merge_add() {
86 #if 0
87 // XXX This is place holder code for reusing an existing String
88 // allocation but the logic for checking the state safety is
89 // probably inadequate at the moment.
90 CallProjections endprojs;
91 sc->end()->extract_projections(&endprojs, false);
92 if (endprojs.resproj != NULL) {
93 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
94 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
95 if (use != NULL && use->method() != NULL &&
96 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
97 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
98 // Found useless new String(sb.toString()) so reuse the newly allocated String
99 // when creating the result instead of allocating a new one.
100 sc->set_string_alloc(use->in(TypeFunc::Parms));
101 sc->set_end(use);
102 }
103 }
104 }
105 #endif
106 }
107
108 StringConcat* merge(StringConcat* other, Node* arg);
109
110 void set_allocation(AllocateNode* alloc) {
111 _begin = alloc;
112 }
113
114 void append(Node* value, int mode) {
115 _arguments->add_req(value);
116 _mode.append(mode);
117 }
118 void push(Node* value, int mode) {
119 _arguments->ins_req(0, value);
120 _mode.insert_before(0, mode);
121 }
122
123 void push_string(Node* value) {
124 push(value, StringMode);
125 }
126 void push_string_null_check(Node* value) {
127 push(value, StringNullCheckMode);
128 }
129 void push_int(Node* value) {
130 push(value, IntMode);
131 }
132 void push_char(Node* value) {
133 push(value, CharMode);
134 }
135
136 static bool is_SB_toString(Node* call) {
137 if (call->is_CallStaticJava()) {
138 CallStaticJavaNode* csj = call->as_CallStaticJava();
139 ciMethod* m = csj->method();
140 if (m != NULL &&
141 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
142 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
143 return true;
144 }
145 }
146 return false;
147 }
148
149 static Node* skip_string_null_check(Node* value) {
150 // Look for a diamond shaped Null check of toString() result
151 // (could be code from String.valueOf()):
152 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
153 if (value->is_Phi()) {
154 int true_path = value->as_Phi()->is_diamond_phi();
155 if (true_path != 0) {
156 // phi->region->if_proj->ifnode->bool
157 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
158 Node* cmp = b->in(1);
159 Node* v1 = cmp->in(1);
160 Node* v2 = cmp->in(2);
161 // Null check of the return of toString which can simply be skipped.
162 if (b->_test._test == BoolTest::ne &&
163 v2->bottom_type() == TypePtr::NULL_PTR &&
164 value->in(true_path)->Opcode() == Op_CastPP &&
165 value->in(true_path)->in(1) == v1 &&
166 v1->is_Proj() && is_SB_toString(v1->in(0))) {
167 return v1;
168 }
169 }
170 }
171 return value;
172 }
173
174 Node* argument(int i) {
175 return _arguments->in(i);
176 }
177 Node* argument_uncast(int i) {
178 Node* arg = argument(i);
179 int amode = mode(i);
180 if (amode == StringConcat::StringMode ||
181 amode == StringConcat::StringNullCheckMode) {
182 arg = skip_string_null_check(arg);
183 }
184 return arg;
185 }
186 void set_argument(int i, Node* value) {
187 _arguments->set_req(i, value);
188 }
189 int num_arguments() {
190 return _mode.length();
191 }
192 int mode(int i) {
193 return _mode.at(i);
194 }
195 void add_control(Node* ctrl) {
196 assert(!_control.contains(ctrl), "only push once");
197 _control.push(ctrl);
198 }
199 void add_constructor(Node* init) {
200 assert(!_constructors.contains(init), "only push once");
201 _constructors.push(init);
202 }
203 CallStaticJavaNode* end() { return _end; }
204 AllocateNode* begin() { return _begin; }
205 Node* string_alloc() { return _string_alloc; }
206
207 void eliminate_unneeded_control();
208 void eliminate_initialize(InitializeNode* init);
209 void eliminate_call(CallNode* call);
210
211 void maybe_log_transform() {
212 CompileLog* log = _stringopts->C->log();
213 if (log != NULL) {
214 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
215 num_arguments(),
216 _string_alloc != NULL,
217 _multiple);
218 JVMState* p = _begin->jvms();
219 while (p != NULL) {
220 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
221 p = p->caller();
222 }
223 log->tail("replace_string_concat");
224 }
225 }
226
227 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
228 for (uint u = 0; u < _uncommon_traps.size(); u++) {
229 Node* uct = _uncommon_traps.at(u);
230
231 // Build a new call using the jvms state of the allocate
232 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
233 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
234 const TypePtr* no_memory_effects = NULL;
235 Compile* C = _stringopts->C;
236 CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
237 jvms->bci(), no_memory_effects);
238 for (int e = 0; e < TypeFunc::Parms; e++) {
239 call->init_req(e, uct->in(e));
240 }
241 // Set the trap request to record intrinsic failure if this trap
242 // is taken too many times. Ideally we would handle then traps by
243 // doing the original bookkeeping in the MDO so that if it caused
244 // the code to be thrown out we could still recompile and use the
245 // optimization. Failing the uncommon traps doesn't really mean
246 // that the optimization is a bad idea but there's no other way to
247 // do the MDO updates currently.
248 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
249 Deoptimization::Action_make_not_entrant);
250 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
251 kit.add_safepoint_edges(call);
252
253 _stringopts->gvn()->transform(call);
254 C->gvn_replace_by(uct, call);
255 uct->disconnect_inputs(NULL, C);
256 }
257 }
258
259 void cleanup() {
260 // disconnect the hook node
261 _arguments->disconnect_inputs(NULL, _stringopts->C);
262 }
263 };
264
265
266 void StringConcat::eliminate_unneeded_control() {
267 for (uint i = 0; i < _control.size(); i++) {
268 Node* n = _control.at(i);
269 if (n->is_Allocate()) {
270 eliminate_initialize(n->as_Allocate()->initialization());
271 }
272 if (n->is_Call()) {
273 if (n != _end) {
274 eliminate_call(n->as_Call());
275 }
276 } else if (n->is_IfTrue()) {
277 Compile* C = _stringopts->C;
278 C->gvn_replace_by(n, n->in(0)->in(0));
279 // get rid of the other projection
280 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
281 }
282 }
283 }
284
285
286 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
287 StringConcat* result = new StringConcat(_stringopts, _end);
288 for (uint x = 0; x < _control.size(); x++) {
289 Node* n = _control.at(x);
290 if (n->is_Call()) {
291 result->_control.push(n);
292 }
293 }
294 for (uint x = 0; x < other->_control.size(); x++) {
295 Node* n = other->_control.at(x);
296 if (n->is_Call()) {
297 result->_control.push(n);
298 }
299 }
300 assert(result->_control.contains(other->_end), "what?");
301 assert(result->_control.contains(_begin), "what?");
302 for (int x = 0; x < num_arguments(); x++) {
303 Node* argx = argument_uncast(x);
304 if (argx == arg) {
305 // replace the toString result with the all the arguments that
306 // made up the other StringConcat
307 for (int y = 0; y < other->num_arguments(); y++) {
308 result->append(other->argument(y), other->mode(y));
309 }
310 } else {
311 result->append(argx, mode(x));
312 }
313 }
314 result->set_allocation(other->_begin);
315 for (uint i = 0; i < _constructors.size(); i++) {
316 result->add_constructor(_constructors.at(i));
317 }
318 for (uint i = 0; i < other->_constructors.size(); i++) {
319 result->add_constructor(other->_constructors.at(i));
320 }
321 result->_multiple = true;
322 return result;
323 }
324
325
326 void StringConcat::eliminate_call(CallNode* call) {
327 Compile* C = _stringopts->C;
328 CallProjections projs;
329 call->extract_projections(&projs, false);
330 if (projs.fallthrough_catchproj != NULL) {
331 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
332 }
333 if (projs.fallthrough_memproj != NULL) {
334 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
335 }
336 if (projs.catchall_memproj != NULL) {
337 C->gvn_replace_by(projs.catchall_memproj, C->top());
338 }
339 if (projs.fallthrough_ioproj != NULL) {
340 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
341 }
342 if (projs.catchall_ioproj != NULL) {
343 C->gvn_replace_by(projs.catchall_ioproj, C->top());
344 }
345 if (projs.catchall_catchproj != NULL) {
346 // EA can't cope with the partially collapsed graph this
347 // creates so put it on the worklist to be collapsed later.
348 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
349 Node *use = i.get();
350 int opc = use->Opcode();
351 if (opc == Op_CreateEx || opc == Op_Region) {
352 _stringopts->record_dead_node(use);
353 }
354 }
355 C->gvn_replace_by(projs.catchall_catchproj, C->top());
356 }
357 if (projs.resproj != NULL) {
358 C->gvn_replace_by(projs.resproj, C->top());
359 }
360 C->gvn_replace_by(call, C->top());
361 }
362
363 void StringConcat::eliminate_initialize(InitializeNode* init) {
364 Compile* C = _stringopts->C;
365
366 // Eliminate Initialize node.
367 assert(init->outcnt() <= 2, "only a control and memory projection expected");
368 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
369 Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
370 if (ctrl_proj != NULL) {
371 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
372 }
373 Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
374 if (mem_proj != NULL) {
375 Node *mem = init->in(TypeFunc::Memory);
376 C->gvn_replace_by(mem_proj, mem);
377 }
378 C->gvn_replace_by(init, C->top());
379 init->disconnect_inputs(NULL, C);
380 }
381
382 Node_List PhaseStringOpts::collect_toString_calls() {
383 Node_List string_calls;
384 Node_List worklist;
385
386 _visited.Clear();
387
388 // Prime the worklist
389 for (uint i = 1; i < C->root()->len(); i++) {
390 Node* n = C->root()->in(i);
391 if (n != NULL && !_visited.test_set(n->_idx)) {
392 worklist.push(n);
393 }
394 }
395
396 while (worklist.size() > 0) {
397 Node* ctrl = worklist.pop();
398 if (StringConcat::is_SB_toString(ctrl)) {
399 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
400 string_calls.push(csj);
401 }
402 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
403 worklist.push(ctrl->in(0));
404 }
405 if (ctrl->is_Region()) {
406 for (uint i = 1; i < ctrl->len(); i++) {
407 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
408 worklist.push(ctrl->in(i));
409 }
410 }
411 }
412 }
413 return string_calls;
414 }
415
416
417 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
418 ciMethod* m = call->method();
419 ciSymbol* string_sig;
420 ciSymbol* int_sig;
421 ciSymbol* char_sig;
422 if (m->holder() == C->env()->StringBuilder_klass()) {
423 string_sig = ciSymbol::String_StringBuilder_signature();
424 int_sig = ciSymbol::int_StringBuilder_signature();
425 char_sig = ciSymbol::char_StringBuilder_signature();
426 } else if (m->holder() == C->env()->StringBuffer_klass()) {
427 string_sig = ciSymbol::String_StringBuffer_signature();
428 int_sig = ciSymbol::int_StringBuffer_signature();
429 char_sig = ciSymbol::char_StringBuffer_signature();
430 } else {
431 return NULL;
432 }
433 #ifndef PRODUCT
434 if (PrintOptimizeStringConcat) {
435 tty->print("considering toString call in ");
436 call->jvms()->dump_spec(tty); tty->cr();
437 }
438 #endif
439
440 StringConcat* sc = new StringConcat(this, call);
441
442 AllocateNode* alloc = NULL;
443 InitializeNode* init = NULL;
444
445 // possible opportunity for StringBuilder fusion
446 CallStaticJavaNode* cnode = call;
447 while (cnode) {
448 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
449 if (recv->is_Proj()) {
450 recv = recv->in(0);
451 }
452 cnode = recv->isa_CallStaticJava();
453 if (cnode == NULL) {
454 alloc = recv->isa_Allocate();
455 if (alloc == NULL) {
456 break;
457 }
458 // Find the constructor call
459 Node* result = alloc->result_cast();
460 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
461 // strange looking allocation
462 #ifndef PRODUCT
463 if (PrintOptimizeStringConcat) {
464 tty->print("giving up because allocation looks strange ");
465 alloc->jvms()->dump_spec(tty); tty->cr();
466 }
467 #endif
468 break;
469 }
470 Node* constructor = NULL;
471 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
472 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
473 if (use != NULL &&
474 use->method() != NULL &&
475 !use->method()->is_static() &&
476 use->method()->name() == ciSymbol::object_initializer_name() &&
477 use->method()->holder() == m->holder()) {
478 // Matched the constructor.
479 ciSymbol* sig = use->method()->signature()->as_symbol();
480 if (sig == ciSymbol::void_method_signature() ||
481 sig == ciSymbol::int_void_signature() ||
482 sig == ciSymbol::string_void_signature()) {
483 if (sig == ciSymbol::string_void_signature()) {
484 // StringBuilder(String) so pick this up as the first argument
485 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
486 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
487 if (type == TypePtr::NULL_PTR) {
488 // StringBuilder(null) throws exception.
489 #ifndef PRODUCT
490 if (PrintOptimizeStringConcat) {
491 tty->print("giving up because StringBuilder(null) throws exception");
492 alloc->jvms()->dump_spec(tty); tty->cr();
493 }
494 #endif
495 return NULL;
496 }
497 // StringBuilder(str) argument needs null check.
498 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
499 }
500 // The int variant takes an initial size for the backing
501 // array so just treat it like the void version.
502 constructor = use;
503 } else {
504 #ifndef PRODUCT
505 if (PrintOptimizeStringConcat) {
506 tty->print("unexpected constructor signature: %s", sig->as_utf8());
507 }
508 #endif
509 }
510 break;
511 }
512 }
513 if (constructor == NULL) {
514 // couldn't find constructor
515 #ifndef PRODUCT
516 if (PrintOptimizeStringConcat) {
517 tty->print("giving up because couldn't find constructor ");
518 alloc->jvms()->dump_spec(tty); tty->cr();
519 }
520 #endif
521 break;
522 }
523
524 // Walked all the way back and found the constructor call so see
525 // if this call converted into a direct string concatenation.
526 sc->add_control(call);
527 sc->add_control(constructor);
528 sc->add_control(alloc);
529 sc->set_allocation(alloc);
530 sc->add_constructor(constructor);
531 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
532 return sc;
533 } else {
534 return NULL;
535 }
536 } else if (cnode->method() == NULL) {
537 break;
538 } else if (!cnode->method()->is_static() &&
539 cnode->method()->holder() == m->holder() &&
540 cnode->method()->name() == ciSymbol::append_name() &&
541 (cnode->method()->signature()->as_symbol() == string_sig ||
542 cnode->method()->signature()->as_symbol() == char_sig ||
543 cnode->method()->signature()->as_symbol() == int_sig)) {
544 sc->add_control(cnode);
545 Node* arg = cnode->in(TypeFunc::Parms + 1);
546 if (cnode->method()->signature()->as_symbol() == int_sig) {
547 sc->push_int(arg);
548 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
549 sc->push_char(arg);
550 } else {
551 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
552 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
553 if (csj->method() != NULL &&
554 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
555 arg->outcnt() == 1) {
556 // _control is the list of StringBuilder calls nodes which
557 // will be replaced by new String code after this optimization.
558 // Integer::toString() call is not part of StringBuilder calls
559 // chain. It could be eliminated only if its result is used
560 // only by this SB calls chain.
561 // Another limitation: it should be used only once because
562 // it is unknown that it is used only by this SB calls chain
563 // until all related SB calls nodes are collected.
564 assert(arg->unique_out() == cnode, "sanity");
565 sc->add_control(csj);
566 sc->push_int(csj->in(TypeFunc::Parms));
567 continue;
568 }
569 }
570 sc->push_string(arg);
571 }
572 continue;
573 } else {
574 // some unhandled signature
575 #ifndef PRODUCT
576 if (PrintOptimizeStringConcat) {
577 tty->print("giving up because encountered unexpected signature ");
578 cnode->tf()->dump(); tty->cr();
579 cnode->in(TypeFunc::Parms + 1)->dump();
580 }
581 #endif
582 break;
583 }
584 }
585 return NULL;
586 }
587
588
589 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
590 Phase(StringOpts),
591 _gvn(gvn),
592 _visited(Thread::current()->resource_area()) {
593
594 assert(OptimizeStringConcat, "shouldn't be here");
595
596 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
597 ciSymbol::make("[I"), true);
598 if (size_table_field == NULL) {
599 // Something wrong so give up.
600 assert(false, "why can't we find Integer.sizeTable?");
601 return;
602 }
603
604 // Collect the types needed to talk about the various slices of memory
605 byte_adr_idx = C->get_alias_index(TypeAryPtr::BYTES);
606
607 // For each locally allocated StringBuffer see if the usages can be
608 // collapsed into a single String construction.
609
610 // Run through the list of allocation looking for SB.toString to see
611 // if it's possible to fuse the usage of the SB into a single String
612 // construction.
613 GrowableArray<StringConcat*> concats;
614 Node_List toStrings = collect_toString_calls();
615 while (toStrings.size() > 0) {
616 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
617 if (sc != NULL) {
618 concats.push(sc);
619 }
620 }
621
622 // try to coalesce separate concats
623 restart:
624 for (int c = 0; c < concats.length(); c++) {
625 StringConcat* sc = concats.at(c);
626 for (int i = 0; i < sc->num_arguments(); i++) {
627 Node* arg = sc->argument_uncast(i);
628 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
629 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
630 for (int o = 0; o < concats.length(); o++) {
631 if (c == o) continue;
632 StringConcat* other = concats.at(o);
633 if (other->end() == csj) {
634 #ifndef PRODUCT
635 if (PrintOptimizeStringConcat) {
636 tty->print_cr("considering stacked concats");
637 }
638 #endif
639
640 StringConcat* merged = sc->merge(other, arg);
641 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
642 #ifndef PRODUCT
643 if (PrintOptimizeStringConcat) {
644 tty->print_cr("stacking would succeed");
645 }
646 #endif
647 if (c < o) {
648 concats.remove_at(o);
649 concats.at_put(c, merged);
650 } else {
651 concats.remove_at(c);
652 concats.at_put(o, merged);
653 }
654 goto restart;
655 } else {
656 #ifndef PRODUCT
657 if (PrintOptimizeStringConcat) {
658 tty->print_cr("stacking would fail");
659 }
660 #endif
661 }
662 }
663 }
664 }
665 }
666 }
667
668
669 for (int c = 0; c < concats.length(); c++) {
670 StringConcat* sc = concats.at(c);
671 replace_string_concat(sc);
672 }
673
674 remove_dead_nodes();
675 }
676
677 void PhaseStringOpts::record_dead_node(Node* dead) {
678 dead_worklist.push(dead);
679 }
680
681 void PhaseStringOpts::remove_dead_nodes() {
682 // Delete any dead nodes to make things clean enough that escape
683 // analysis doesn't get unhappy.
684 while (dead_worklist.size() > 0) {
685 Node* use = dead_worklist.pop();
686 int opc = use->Opcode();
687 switch (opc) {
688 case Op_Region: {
689 uint i = 1;
690 for (i = 1; i < use->req(); i++) {
691 if (use->in(i) != C->top()) {
692 break;
693 }
694 }
695 if (i >= use->req()) {
696 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
697 Node* m = i.get();
698 if (m->is_Phi()) {
699 dead_worklist.push(m);
700 }
701 }
702 C->gvn_replace_by(use, C->top());
703 }
704 break;
705 }
706 case Op_AddP:
707 case Op_CreateEx: {
708 // Recurisvely clean up references to CreateEx so EA doesn't
709 // get unhappy about the partially collapsed graph.
710 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
711 Node* m = i.get();
712 if (m->is_AddP()) {
713 dead_worklist.push(m);
714 }
715 }
716 C->gvn_replace_by(use, C->top());
717 break;
718 }
719 case Op_Phi:
720 if (use->in(0) == C->top()) {
721 C->gvn_replace_by(use, C->top());
722 }
723 break;
724 }
725 }
726 }
727
728
729 bool StringConcat::validate_mem_flow() {
730 Compile* C = _stringopts->C;
731
732 for (uint i = 0; i < _control.size(); i++) {
733 #ifndef PRODUCT
734 Node_List path;
735 #endif
736 Node* curr = _control.at(i);
737 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
738 // Now here's the main invariant in our case:
739 // For memory between the constructor, and appends, and toString we should only see bottom memory,
740 // produced by the previous call we know about.
741 if (!_constructors.contains(curr)) {
742 NOT_PRODUCT(path.push(curr);)
743 Node* mem = curr->in(TypeFunc::Memory);
744 assert(mem != NULL, "calls should have memory edge");
745 assert(!mem->is_Phi(), "should be handled by control flow validation");
746 NOT_PRODUCT(path.push(mem);)
747 while (mem->is_MergeMem()) {
748 for (uint i = 1; i < mem->req(); i++) {
749 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
750 #ifndef PRODUCT
751 if (PrintOptimizeStringConcat) {
752 tty->print("fusion has incorrect memory flow (side effects) for ");
753 _begin->jvms()->dump_spec(tty); tty->cr();
754 path.dump();
755 }
756 #endif
757 return false;
758 }
759 }
760 // skip through a potential MergeMem chain, linked through Bot
761 mem = mem->in(Compile::AliasIdxBot);
762 NOT_PRODUCT(path.push(mem);)
763 }
764 // now let it fall through, and see if we have a projection
765 if (mem->is_Proj()) {
766 // Should point to a previous known call
767 Node *prev = mem->in(0);
768 NOT_PRODUCT(path.push(prev);)
769 if (!prev->is_Call() || !_control.contains(prev)) {
770 #ifndef PRODUCT
771 if (PrintOptimizeStringConcat) {
772 tty->print("fusion has incorrect memory flow (unknown call) for ");
773 _begin->jvms()->dump_spec(tty); tty->cr();
774 path.dump();
775 }
776 #endif
777 return false;
778 }
779 } else {
780 assert(mem->is_Store() || mem->is_LoadStore(), "unexpected node type: %s", mem->Name());
781 #ifndef PRODUCT
782 if (PrintOptimizeStringConcat) {
783 tty->print("fusion has incorrect memory flow (unexpected source) for ");
784 _begin->jvms()->dump_spec(tty); tty->cr();
785 path.dump();
786 }
787 #endif
788 return false;
789 }
790 } else {
791 // For memory that feeds into constructors it's more complicated.
792 // However the advantage is that any side effect that happens between the Allocate/Initialize and
793 // the constructor will have to be control-dependent on Initialize.
794 // So we actually don't have to do anything, since it's going to be caught by the control flow
795 // analysis.
796 #ifdef ASSERT
797 // Do a quick verification of the control pattern between the constructor and the initialize node
798 assert(curr->is_Call(), "constructor should be a call");
799 // Go up the control starting from the constructor call
800 Node* ctrl = curr->in(0);
801 IfNode* iff = NULL;
802 RegionNode* copy = NULL;
803
804 while (true) {
805 // skip known check patterns
806 if (ctrl->is_Region()) {
807 if (ctrl->as_Region()->is_copy()) {
808 copy = ctrl->as_Region();
809 ctrl = copy->is_copy();
810 } else { // a cast
811 assert(ctrl->req() == 3 &&
812 ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() &&
813 ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() &&
814 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
815 ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(),
816 "must be a simple diamond");
817 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
818 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
819 Node* use = i.get();
820 assert(use == ctrl || use->is_ConstraintCast(),
821 "unexpected user: %s", use->Name());
822 }
823
824 iff = ctrl->in(1)->in(0)->as_If();
825 ctrl = iff->in(0);
826 }
827 } else if (ctrl->is_IfTrue()) { // null checks, class checks
828 iff = ctrl->in(0)->as_If();
829 // Verify that the other arm is an uncommon trap
830 Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
831 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
832 assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommon trap");
833 ctrl = iff->in(0);
834 } else {
835 break;
836 }
837 }
838
839 assert(ctrl->is_Proj(), "must be a projection");
840 assert(ctrl->in(0)->is_Initialize(), "should be initialize");
841 for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) {
842 Node* use = i.get();
843 assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(),
844 "unexpected user: %s", use->Name());
845 }
846 #endif // ASSERT
847 }
848 }
849 }
850
851 #ifndef PRODUCT
852 if (PrintOptimizeStringConcat) {
853 tty->print("fusion has correct memory flow for ");
854 _begin->jvms()->dump_spec(tty); tty->cr();
855 tty->cr();
856 }
857 #endif
858 return true;
859 }
860
861 bool StringConcat::validate_control_flow() {
862 // We found all the calls and arguments now lets see if it's
863 // safe to transform the graph as we would expect.
864
865 // Check to see if this resulted in too many uncommon traps previously
866 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
867 Deoptimization::Reason_intrinsic)) {
868 return false;
869 }
870
871 // Walk backwards over the control flow from toString to the
872 // allocation and make sure all the control flow is ok. This
873 // means it's either going to be eliminated once the calls are
874 // removed or it can safely be transformed into an uncommon
875 // trap.
876
877 int null_check_count = 0;
878 Unique_Node_List ctrl_path;
879
880 assert(_control.contains(_begin), "missing");
881 assert(_control.contains(_end), "missing");
882
883 // Collect the nodes that we know about and will eliminate into ctrl_path
884 for (uint i = 0; i < _control.size(); i++) {
885 // Push the call and it's control projection
886 Node* n = _control.at(i);
887 if (n->is_Allocate()) {
888 AllocateNode* an = n->as_Allocate();
889 InitializeNode* init = an->initialization();
890 ctrl_path.push(init);
891 ctrl_path.push(init->as_Multi()->proj_out(0));
892 }
893 if (n->is_Call()) {
894 CallNode* cn = n->as_Call();
895 ctrl_path.push(cn);
896 ctrl_path.push(cn->proj_out(0));
897 ctrl_path.push(cn->proj_out(0)->unique_out());
898 Node* catchproj = cn->proj_out(0)->unique_out()->as_Catch()->proj_out_or_null(0);
899 if (catchproj != NULL) {
900 ctrl_path.push(catchproj);
901 }
902 } else {
903 ShouldNotReachHere();
904 }
905 }
906
907 // Skip backwards through the control checking for unexpected control flow
908 Node* ptr = _end;
909 bool fail = false;
910 while (ptr != _begin) {
911 if (ptr->is_Call() && ctrl_path.member(ptr)) {
912 ptr = ptr->in(0);
913 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
914 ptr = ptr->in(0)->in(0)->in(0);
915 assert(ctrl_path.member(ptr), "should be a known piece of control");
916 } else if (ptr->is_IfTrue()) {
917 IfNode* iff = ptr->in(0)->as_If();
918 BoolNode* b = iff->in(1)->isa_Bool();
919
920 if (b == NULL) {
921 #ifndef PRODUCT
922 if (PrintOptimizeStringConcat) {
923 tty->print_cr("unexpected input to IfNode");
924 iff->in(1)->dump();
925 tty->cr();
926 }
927 #endif
928 fail = true;
929 break;
930 }
931
932 Node* cmp = b->in(1);
933 Node* v1 = cmp->in(1);
934 Node* v2 = cmp->in(2);
935 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
936
937 // Null check of the return of append which can simply be eliminated
938 if (b->_test._test == BoolTest::ne &&
939 v2->bottom_type() == TypePtr::NULL_PTR &&
940 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
941 // NULL check of the return value of the append
942 null_check_count++;
943 if (otherproj->outcnt() == 1) {
944 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
945 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
946 ctrl_path.push(call);
947 }
948 }
949 _control.push(ptr);
950 ptr = ptr->in(0)->in(0);
951 continue;
952 }
953
954 // A test which leads to an uncommon trap which should be safe.
955 // Later this trap will be converted into a trap that restarts
956 // at the beginning.
957 if (otherproj->outcnt() == 1) {
958 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
959 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
960 // control flow leads to uct so should be ok
961 _uncommon_traps.push(call);
962 ctrl_path.push(call);
963 ptr = ptr->in(0)->in(0);
964 continue;
965 }
966 }
967
968 #ifndef PRODUCT
969 // Some unexpected control flow we don't know how to handle.
970 if (PrintOptimizeStringConcat) {
971 tty->print_cr("failing with unknown test");
972 b->dump();
973 cmp->dump();
974 v1->dump();
975 v2->dump();
976 tty->cr();
977 }
978 #endif
979 fail = true;
980 break;
981 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
982 ptr = ptr->in(0)->in(0);
983 } else if (ptr->is_Region()) {
984 Node* copy = ptr->as_Region()->is_copy();
985 if (copy != NULL) {
986 ptr = copy;
987 continue;
988 }
989 if (ptr->req() == 3 &&
990 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
991 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
992 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
993 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
994 // Simple diamond.
995 // XXX should check for possibly merging stores. simple data merges are ok.
996 // The IGVN will make this simple diamond go away when it
997 // transforms the Region. Make sure it sees it.
998 Compile::current()->record_for_igvn(ptr);
999 ptr = ptr->in(1)->in(0)->in(0);
1000 continue;
1001 }
1002 #ifndef PRODUCT
1003 if (PrintOptimizeStringConcat) {
1004 tty->print_cr("fusion would fail for region");
1005 _begin->dump();
1006 ptr->dump(2);
1007 }
1008 #endif
1009 fail = true;
1010 break;
1011 } else {
1012 // other unknown control
1013 if (!fail) {
1014 #ifndef PRODUCT
1015 if (PrintOptimizeStringConcat) {
1016 tty->print_cr("fusion would fail for");
1017 _begin->dump();
1018 }
1019 #endif
1020 fail = true;
1021 }
1022 #ifndef PRODUCT
1023 if (PrintOptimizeStringConcat) {
1024 ptr->dump();
1025 }
1026 #endif
1027 ptr = ptr->in(0);
1028 }
1029 }
1030 #ifndef PRODUCT
1031 if (PrintOptimizeStringConcat && fail) {
1032 tty->cr();
1033 }
1034 #endif
1035 if (fail) return !fail;
1036
1037 // Validate that all these results produced are contained within
1038 // this cluster of objects. First collect all the results produced
1039 // by calls in the region.
1040 _stringopts->_visited.Clear();
1041 Node_List worklist;
1042 Node* final_result = _end->proj_out_or_null(TypeFunc::Parms);
1043 for (uint i = 0; i < _control.size(); i++) {
1044 CallNode* cnode = _control.at(i)->isa_Call();
1045 if (cnode != NULL) {
1046 _stringopts->_visited.test_set(cnode->_idx);
1047 }
1048 Node* result = cnode != NULL ? cnode->proj_out_or_null(TypeFunc::Parms) : NULL;
1049 if (result != NULL && result != final_result) {
1050 worklist.push(result);
1051 }
1052 }
1053
1054 Node* last_result = NULL;
1055 while (worklist.size() > 0) {
1056 Node* result = worklist.pop();
1057 if (_stringopts->_visited.test_set(result->_idx))
1058 continue;
1059 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
1060 Node *use = i.get();
1061 if (ctrl_path.member(use)) {
1062 // already checked this
1063 continue;
1064 }
1065 int opc = use->Opcode();
1066 if (opc == Op_CmpP || opc == Op_Node) {
1067 ctrl_path.push(use);
1068 continue;
1069 }
1070 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
1071 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
1072 worklist.push(j.get());
1073 }
1074 worklist.push(use->in(1));
1075 ctrl_path.push(use);
1076 continue;
1077 }
1078 #ifndef PRODUCT
1079 if (PrintOptimizeStringConcat) {
1080 if (result != last_result) {
1081 last_result = result;
1082 tty->print_cr("extra uses for result:");
1083 last_result->dump();
1084 }
1085 use->dump();
1086 }
1087 #endif
1088 fail = true;
1089 break;
1090 }
1091 }
1092
1093 #ifndef PRODUCT
1094 if (PrintOptimizeStringConcat && !fail) {
1095 ttyLocker ttyl;
1096 tty->cr();
1097 tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size());
1098 _begin->jvms()->dump_spec(tty); tty->cr();
1099 for (int i = 0; i < num_arguments(); i++) {
1100 argument(i)->dump();
1101 }
1102 _control.dump();
1103 tty->cr();
1104 }
1105 #endif
1106
1107 return !fail;
1108 }
1109
1110 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
1111 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
1112 Node* klass_node = __ makecon(mirror_type);
1113 BasicType bt = field->layout_type();
1114 ciType* field_klass = field->type();
1115
1116 const Type *type;
1117 if( bt == T_OBJECT ) {
1118 if (!field->type()->is_loaded()) {
1119 type = TypeInstPtr::BOTTOM;
1120 } else if (field->is_static_constant()) {
1121 // This can happen if the constant oop is non-perm.
1122 ciObject* con = field->constant_value().as_object();
1123 // Do not "join" in the previous type; it doesn't add value,
1124 // and may yield a vacuous result if the field is of interface type.
1125 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
1126 assert(type != NULL, "field singleton type must be consistent");
1127 return __ makecon(type);
1128 } else {
1129 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
1130 }
1131 } else {
1132 type = Type::get_const_basic_type(bt);
1133 }
1134
1135 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
1136 type, T_OBJECT,
1137 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())),
1138 MemNode::unordered);
1139 }
1140
1141 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1142 if (arg->is_Con()) {
1143 // Constant integer. Compute constant length using Integer.sizeTable
1144 int arg_val = arg->get_int();
1145 int count = 1;
1146 if (arg_val < 0) {
1147 arg_val = -arg_val;
1148 count++;
1149 }
1150
1151 ciArray* size_table = (ciArray*)size_table_field->constant_value().as_object();
1152 for (int i = 0; i < size_table->length(); i++) {
1153 if (arg_val <= size_table->element_value(i).as_int()) {
1154 count += i;
1155 break;
1156 }
1157 }
1158 return __ intcon(count);
1159 }
1160
1161 RegionNode *final_merge = new RegionNode(3);
1162 kit.gvn().set_type(final_merge, Type::CONTROL);
1163 Node* final_size = new PhiNode(final_merge, TypeInt::INT);
1164 kit.gvn().set_type(final_size, TypeInt::INT);
1165
1166 IfNode* iff = kit.create_and_map_if(kit.control(),
1167 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1168 PROB_FAIR, COUNT_UNKNOWN);
1169 Node* is_min = __ IfFalse(iff);
1170 final_merge->init_req(1, is_min);
1171 final_size->init_req(1, __ intcon(11));
1172
1173 kit.set_control(__ IfTrue(iff));
1174 if (kit.stopped()) {
1175 final_merge->init_req(2, C->top());
1176 final_size->init_req(2, C->top());
1177 } else {
1178
1179 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1180 RegionNode *r = new RegionNode(3);
1181 kit.gvn().set_type(r, Type::CONTROL);
1182 Node *phi = new PhiNode(r, TypeInt::INT);
1183 kit.gvn().set_type(phi, TypeInt::INT);
1184 Node *size = new PhiNode(r, TypeInt::INT);
1185 kit.gvn().set_type(size, TypeInt::INT);
1186 Node* chk = __ CmpI(arg, __ intcon(0));
1187 Node* p = __ Bool(chk, BoolTest::lt);
1188 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1189 Node* lessthan = __ IfTrue(iff);
1190 Node* greaterequal = __ IfFalse(iff);
1191 r->init_req(1, lessthan);
1192 phi->init_req(1, __ SubI(__ intcon(0), arg));
1193 size->init_req(1, __ intcon(1));
1194 r->init_req(2, greaterequal);
1195 phi->init_req(2, arg);
1196 size->init_req(2, __ intcon(0));
1197 kit.set_control(r);
1198 C->record_for_igvn(r);
1199 C->record_for_igvn(phi);
1200 C->record_for_igvn(size);
1201
1202 // for (int i=0; ; i++)
1203 // if (x <= sizeTable[i])
1204 // return i+1;
1205
1206 // Add loop predicate first.
1207 kit.add_predicate();
1208
1209 RegionNode *loop = new RegionNode(3);
1210 loop->init_req(1, kit.control());
1211 kit.gvn().set_type(loop, Type::CONTROL);
1212
1213 Node *index = new PhiNode(loop, TypeInt::INT);
1214 index->init_req(1, __ intcon(0));
1215 kit.gvn().set_type(index, TypeInt::INT);
1216 kit.set_control(loop);
1217 Node* sizeTable = fetch_static_field(kit, size_table_field);
1218
1219 sizeTable = kit.access_resolve(sizeTable, ACCESS_READ);
1220 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1221 C->record_for_igvn(value);
1222 Node* limit = __ CmpI(phi, value);
1223 Node* limitb = __ Bool(limit, BoolTest::le);
1224 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1225 Node* lessEqual = __ IfTrue(iff2);
1226 Node* greater = __ IfFalse(iff2);
1227
1228 loop->init_req(2, greater);
1229 index->init_req(2, __ AddI(index, __ intcon(1)));
1230
1231 kit.set_control(lessEqual);
1232 C->record_for_igvn(loop);
1233 C->record_for_igvn(index);
1234
1235 final_merge->init_req(2, kit.control());
1236 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1237 }
1238
1239 kit.set_control(final_merge);
1240 C->record_for_igvn(final_merge);
1241 C->record_for_igvn(final_size);
1242
1243 return final_size;
1244 }
1245
1246 // Simplified version of Integer.getChars
1247 void PhaseStringOpts::getChars(GraphKit& kit, Node* arg, Node* dst_array, BasicType bt, Node* end, Node* final_merge, Node* final_mem, int merge_index) {
1248 // if (i < 0) {
1249 // sign = '-';
1250 // i = -i;
1251 // }
1252 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1253 PROB_FAIR, COUNT_UNKNOWN);
1254
1255 RegionNode* merge = new RegionNode(3);
1256 kit.gvn().set_type(merge, Type::CONTROL);
1257 Node* i = new PhiNode(merge, TypeInt::INT);
1258 kit.gvn().set_type(i, TypeInt::INT);
1259 Node* sign = new PhiNode(merge, TypeInt::INT);
1260 kit.gvn().set_type(sign, TypeInt::INT);
1261
1262 merge->init_req(1, __ IfTrue(iff));
1263 i->init_req(1, __ SubI(__ intcon(0), arg));
1264 sign->init_req(1, __ intcon('-'));
1265 merge->init_req(2, __ IfFalse(iff));
1266 i->init_req(2, arg);
1267 sign->init_req(2, __ intcon(0));
1268
1269 kit.set_control(merge);
1270
1271 C->record_for_igvn(merge);
1272 C->record_for_igvn(i);
1273 C->record_for_igvn(sign);
1274
1275 // for (;;) {
1276 // q = i / 10;
1277 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1278 // buf [--charPos] = digits [r];
1279 // i = q;
1280 // if (i == 0) break;
1281 // }
1282
1283 // Add loop predicate first.
1284 kit.add_predicate();
1285
1286 RegionNode* head = new RegionNode(3);
1287 head->init_req(1, kit.control());
1288
1289 kit.gvn().set_type(head, Type::CONTROL);
1290 Node* i_phi = new PhiNode(head, TypeInt::INT);
1291 i_phi->init_req(1, i);
1292 kit.gvn().set_type(i_phi, TypeInt::INT);
1293 Node* charPos = new PhiNode(head, TypeInt::INT);
1294 charPos->init_req(1, end);
1295 kit.gvn().set_type(charPos, TypeInt::INT);
1296 Node* mem = PhiNode::make(head, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1297 kit.gvn().set_type(mem, Type::MEMORY);
1298
1299 kit.set_control(head);
1300 kit.set_memory(mem, byte_adr_idx);
1301
1302 Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));
1303 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1304 __ LShiftI(q, __ intcon(1))));
1305 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1306 Node* ch = __ AddI(r, __ intcon('0'));
1307 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1308 ch, bt, byte_adr_idx, MemNode::unordered, (bt != T_BYTE) /* mismatched */);
1309
1310 iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1311 PROB_FAIR, COUNT_UNKNOWN);
1312 Node* ne = __ IfTrue(iff);
1313 Node* eq = __ IfFalse(iff);
1314
1315 head->init_req(2, ne);
1316 mem->init_req(2, st);
1317
1318 i_phi->init_req(2, q);
1319 charPos->init_req(2, index);
1320 charPos = index;
1321
1322 kit.set_control(eq);
1323 kit.set_memory(st, byte_adr_idx);
1324
1325 C->record_for_igvn(head);
1326 C->record_for_igvn(mem);
1327 C->record_for_igvn(i_phi);
1328 C->record_for_igvn(charPos);
1329
1330 // if (sign != 0) {
1331 // buf [--charPos] = sign;
1332 // }
1333 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1334 PROB_FAIR, COUNT_UNKNOWN);
1335
1336 final_merge->init_req(merge_index + 2, __ IfFalse(iff));
1337 final_mem->init_req(merge_index + 2, kit.memory(byte_adr_idx));
1338
1339 kit.set_control(__ IfTrue(iff));
1340 if (kit.stopped()) {
1341 final_merge->init_req(merge_index + 1, C->top());
1342 final_mem->init_req(merge_index + 1, C->top());
1343 } else {
1344 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1345 st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1346 sign, bt, byte_adr_idx, MemNode::unordered, (bt != T_BYTE) /* mismatched */);
1347
1348 final_merge->init_req(merge_index + 1, kit.control());
1349 final_mem->init_req(merge_index + 1, st);
1350 }
1351 }
1352
1353 // Copy the characters representing arg into dst_array starting at start
1354 Node* PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* dst_array, Node* dst_coder, Node* start, Node* size) {
1355 bool dcon = dst_coder->is_Con();
1356 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1357 Node* end = __ AddI(start, __ LShiftI(size, dst_coder));
1358
1359 // The final_merge node has 4 entries in case the encoding is known:
1360 // (0) Control, (1) result w/ sign, (2) result w/o sign, (3) result for Integer.min_value
1361 // or 6 entries in case the encoding is not known:
1362 // (0) Control, (1) Latin1 w/ sign, (2) Latin1 w/o sign, (3) min_value, (4) UTF16 w/ sign, (5) UTF16 w/o sign
1363 RegionNode* final_merge = new RegionNode(dcon ? 4 : 6);
1364 kit.gvn().set_type(final_merge, Type::CONTROL);
1365
1366 Node* final_mem = PhiNode::make(final_merge, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1367 kit.gvn().set_type(final_mem, Type::MEMORY);
1368
1369 // need to handle arg == Integer.MIN_VALUE specially because negating doesn't make it positive
1370 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1371 PROB_FAIR, COUNT_UNKNOWN);
1372
1373 Node* old_mem = kit.memory(byte_adr_idx);
1374
1375 kit.set_control(__ IfFalse(iff));
1376 if (kit.stopped()) {
1377 // Statically not equal to MIN_VALUE so this path is dead
1378 final_merge->init_req(3, kit.control());
1379 } else {
1380 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1381 dst_array, dst_coder, start);
1382 final_merge->init_req(3, kit.control());
1383 final_mem->init_req(3, kit.memory(byte_adr_idx));
1384 }
1385
1386 kit.set_control(__ IfTrue(iff));
1387 kit.set_memory(old_mem, byte_adr_idx);
1388
1389 if (!dcon) {
1390 // Check encoding of destination
1391 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(dst_coder, __ intcon(0)), BoolTest::eq),
1392 PROB_FAIR, COUNT_UNKNOWN);
1393 old_mem = kit.memory(byte_adr_idx);
1394 }
1395 if (!dcon || dbyte) {
1396 // Destination is Latin1,
1397 if (!dcon) {
1398 kit.set_control(__ IfTrue(iff));
1399 }
1400 getChars(kit, arg, dst_array, T_BYTE, end, final_merge, final_mem);
1401 }
1402 if (!dcon || !dbyte) {
1403 // Destination is UTF16
1404 int merge_index = 0;
1405 if (!dcon) {
1406 kit.set_control(__ IfFalse(iff));
1407 kit.set_memory(old_mem, byte_adr_idx);
1408 merge_index = 3; // Account for Latin1 case
1409 }
1410 getChars(kit, arg, dst_array, T_CHAR, end, final_merge, final_mem, merge_index);
1411 }
1412
1413 // Final merge point for Latin1 and UTF16 case
1414 kit.set_control(final_merge);
1415 kit.set_memory(final_mem, byte_adr_idx);
1416
1417 C->record_for_igvn(final_merge);
1418 C->record_for_igvn(final_mem);
1419 return end;
1420 }
1421
1422 // Copy 'count' bytes/chars from src_array to dst_array starting at index start
1423 void PhaseStringOpts::arraycopy(GraphKit& kit, IdealKit& ideal, Node* src_array, Node* dst_array, BasicType elembt, Node* start, Node* count) {
1424 assert(elembt == T_BYTE || elembt == T_CHAR, "Invalid type for arraycopy");
1425
1426 if (elembt == T_CHAR) {
1427 // Get number of chars
1428 count = __ RShiftI(count, __ intcon(1));
1429 }
1430
1431 Node* extra = NULL;
1432 #ifdef _LP64
1433 count = __ ConvI2L(count);
1434 extra = C->top();
1435 #endif
1436
1437 Node* src_ptr = __ array_element_address(src_array, __ intcon(0), T_BYTE);
1438 Node* dst_ptr = __ array_element_address(dst_array, start, T_BYTE);
1439 // Check if destination address is aligned to HeapWordSize
1440 const TypeInt* tdst = __ gvn().type(start)->is_int();
1441 bool aligned = tdst->is_con() && ((tdst->get_con() * type2aelembytes(T_BYTE)) % HeapWordSize == 0);
1442 // Figure out which arraycopy runtime method to call (disjoint, uninitialized).
1443 const char* copyfunc_name = "arraycopy";
1444 address copyfunc_addr = StubRoutines::select_arraycopy_function(elembt, aligned, true, copyfunc_name, true);
1445 ideal.make_leaf_call_no_fp(OptoRuntime::fast_arraycopy_Type(), copyfunc_addr, copyfunc_name,
1446 TypeAryPtr::BYTES, src_ptr, dst_ptr, count, extra);
1447 }
1448
1449 #undef __
1450 #define __ ideal.
1451
1452 // Copy contents of a Latin1 encoded string from src_array to dst_array
1453 void PhaseStringOpts::copy_latin1_string(GraphKit& kit, IdealKit& ideal, Node* src_array, IdealVariable& count,
1454 Node* dst_array, Node* dst_coder, Node* start) {
1455 bool dcon = dst_coder->is_Con();
1456 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1457
1458 if (!dcon) {
1459 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1460 }
1461 if (!dcon || dbyte) {
1462 // Destination is Latin1. Simply emit a byte arraycopy.
1463 arraycopy(kit, ideal, src_array, dst_array, T_BYTE, start, __ value(count));
1464 }
1465 if (!dcon) {
1466 __ else_();
1467 }
1468 if (!dcon || !dbyte) {
1469 // Destination is UTF16. Inflate src_array into dst_array.
1470 kit.sync_kit(ideal);
1471 if (Matcher::match_rule_supported(Op_StrInflatedCopy)) {
1472 // Use fast intrinsic
1473 Node* src = kit.array_element_address(src_array, kit.intcon(0), T_BYTE);
1474 Node* dst = kit.array_element_address(dst_array, start, T_BYTE);
1475 kit.inflate_string(src, dst, TypeAryPtr::BYTES, __ value(count));
1476 } else {
1477 // No intrinsic available, use slow method
1478 kit.inflate_string_slow(src_array, dst_array, start, __ value(count));
1479 }
1480 ideal.sync_kit(&kit);
1481 // Multiply count by two since we now need two bytes per char
1482 __ set(count, __ LShiftI(__ value(count), __ ConI(1)));
1483 }
1484 if (!dcon) {
1485 __ end_if();
1486 }
1487 }
1488
1489 // Read two bytes from index and index+1 and convert them to a char
1490 static jchar readChar(ciTypeArray* array, int index) {
1491 int shift_high, shift_low;
1492 #ifdef VM_LITTLE_ENDIAN
1493 shift_high = 0;
1494 shift_low = 8;
1495 #else
1496 shift_high = 8;
1497 shift_low = 0;
1498 #endif
1499
1500 jchar b1 = ((jchar) array->byte_at(index)) & 0xff;
1501 jchar b2 = ((jchar) array->byte_at(index+1)) & 0xff;
1502 return (b1 << shift_high) | (b2 << shift_low);
1503 }
1504
1505 // Copy contents of constant src_array to dst_array by emitting individual stores
1506 void PhaseStringOpts::copy_constant_string(GraphKit& kit, IdealKit& ideal, ciTypeArray* src_array, IdealVariable& count,
1507 bool src_is_byte, Node* dst_array, Node* dst_coder, Node* start) {
1508 bool dcon = dst_coder->is_Con();
1509 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1510 int length = src_array->length();
1511
1512 if (!dcon) {
1513 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1514 }
1515 if (!dcon || dbyte) {
1516 // Destination is Latin1. Copy each byte of src_array into dst_array.
1517 Node* index = start;
1518 for (int i = 0; i < length; i++) {
1519 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1520 Node* val = __ ConI(src_array->byte_at(i));
1521 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1522 index = __ AddI(index, __ ConI(1));
1523 }
1524 }
1525 if (!dcon) {
1526 __ else_();
1527 }
1528 if (!dcon || !dbyte) {
1529 // Destination is UTF16. Copy each char of src_array into dst_array.
1530 Node* index = start;
1531 for (int i = 0; i < length; i++) {
1532 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1533 jchar val;
1534 if (src_is_byte) {
1535 val = src_array->byte_at(i) & 0xff;
1536 } else {
1537 val = readChar(src_array, i++);
1538 }
1539 __ store(__ ctrl(), adr, __ ConI(val), T_CHAR, byte_adr_idx, MemNode::unordered, true /* mismatched */);
1540 index = __ AddI(index, __ ConI(2));
1541 }
1542 if (src_is_byte) {
1543 // Multiply count by two since we now need two bytes per char
1544 __ set(count, __ ConI(2 * length));
1545 }
1546 }
1547 if (!dcon) {
1548 __ end_if();
1549 }
1550 }
1551
1552 // Compress copy contents of the byte/char String str into dst_array starting at index start.
1553 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* dst_array, Node* dst_coder, Node* start) {
1554 Node* src_array = kit.load_String_value(str, true);
1555 src_array = kit.access_resolve(src_array, ACCESS_READ);
1556
1557 IdealKit ideal(&kit, true, true);
1558 IdealVariable count(ideal); __ declarations_done();
1559
1560 if (str->is_Con()) {
1561 // Constant source string
1562 ciTypeArray* src_array_type = get_constant_value(kit, str);
1563
1564 // Check encoding of constant string
1565 bool src_is_byte = (get_constant_coder(kit, str) == java_lang_String::CODER_LATIN1);
1566
1567 // For small constant strings just emit individual stores.
1568 // A length of 6 seems like a good space/speed tradeof.
1569 __ set(count, __ ConI(src_array_type->length()));
1570 int src_len = src_array_type->length() / (src_is_byte ? 1 : 2);
1571 if (src_len < unroll_string_copy_length) {
1572 // Small constant string
1573 copy_constant_string(kit, ideal, src_array_type, count, src_is_byte, dst_array, dst_coder, start);
1574 } else if (src_is_byte) {
1575 // Source is Latin1
1576 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1577 } else {
1578 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1579 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1580 }
1581 } else {
1582 Node* size = kit.load_array_length(src_array);
1583 __ set(count, size);
1584 // Non-constant source string
1585 if (CompactStrings) {
1586 // Emit runtime check for coder
1587 Node* coder = kit.load_String_coder(str, true);
1588 __ if_then(coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1)); {
1589 // Source is Latin1
1590 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1591 } __ else_();
1592 }
1593 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1594 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1595
1596 if (CompactStrings) {
1597 __ end_if();
1598 }
1599 }
1600
1601 // Finally sync IdealKit and GraphKit.
1602 kit.sync_kit(ideal);
1603 return __ AddI(start, __ value(count));
1604 }
1605
1606 // Compress copy the char into dst_array at index start.
1607 Node* PhaseStringOpts::copy_char(GraphKit& kit, Node* val, Node* dst_array, Node* dst_coder, Node* start) {
1608 bool dcon = (dst_coder != NULL) && dst_coder->is_Con();
1609 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1610
1611 IdealKit ideal(&kit, true, true);
1612 IdealVariable end(ideal); __ declarations_done();
1613 Node* adr = kit.array_element_address(dst_array, start, T_BYTE);
1614 if (!dcon){
1615 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1616 }
1617 if (!dcon || dbyte) {
1618 // Destination is Latin1. Store a byte.
1619 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1620 __ set(end, __ AddI(start, __ ConI(1)));
1621 }
1622 if (!dcon) {
1623 __ else_();
1624 }
1625 if (!dcon || !dbyte) {
1626 // Destination is UTF16. Store a char.
1627 __ store(__ ctrl(), adr, val, T_CHAR, byte_adr_idx, MemNode::unordered, true /* mismatched */);
1628 __ set(end, __ AddI(start, __ ConI(2)));
1629 }
1630 if (!dcon) {
1631 __ end_if();
1632 }
1633 // Finally sync IdealKit and GraphKit.
1634 kit.sync_kit(ideal);
1635 return __ value(end);
1636 }
1637
1638 #undef __
1639 #define __ kit.
1640
1641 // Allocate a byte array of specified length.
1642 Node* PhaseStringOpts::allocate_byte_array(GraphKit& kit, IdealKit* ideal, Node* length) {
1643 if (ideal != NULL) {
1644 // Sync IdealKit and graphKit.
1645 kit.sync_kit(*ideal);
1646 }
1647 Node* byte_array = NULL;
1648 {
1649 PreserveReexecuteState preexecs(&kit);
1650 // The original jvms is for an allocation of either a String or
1651 // StringBuffer so no stack adjustment is necessary for proper
1652 // reexecution. If we deoptimize in the slow path the bytecode
1653 // will be reexecuted and the char[] allocation will be thrown away.
1654 kit.jvms()->set_should_reexecute(true);
1655 byte_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_BYTE))),
1656 length, 1);
1657 }
1658
1659 // Mark the allocation so that zeroing is skipped since the code
1660 // below will overwrite the entire array
1661 AllocateArrayNode* byte_alloc = AllocateArrayNode::Ideal_array_allocation(byte_array, _gvn);
1662 byte_alloc->maybe_set_complete(_gvn);
1663
1664 if (ideal != NULL) {
1665 // Sync IdealKit and graphKit.
1666 ideal->sync_kit(&kit);
1667 }
1668 return byte_array;
1669 }
1670
1671 jbyte PhaseStringOpts::get_constant_coder(GraphKit& kit, Node* str) {
1672 assert(str->is_Con(), "String must be constant");
1673 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1674 ciInstance* str_instance = str_type->const_oop()->as_instance();
1675 jbyte coder = str_instance->field_value_by_offset(java_lang_String::coder_offset_in_bytes()).as_byte();
1676 assert(CompactStrings || (coder == java_lang_String::CODER_UTF16), "Strings must be UTF16 encoded");
1677 return coder;
1678 }
1679
1680 int PhaseStringOpts::get_constant_length(GraphKit& kit, Node* str) {
1681 assert(str->is_Con(), "String must be constant");
1682 return get_constant_value(kit, str)->length();
1683 }
1684
1685 ciTypeArray* PhaseStringOpts::get_constant_value(GraphKit& kit, Node* str) {
1686 assert(str->is_Con(), "String must be constant");
1687 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1688 ciInstance* str_instance = str_type->const_oop()->as_instance();
1689 ciObject* src_array = str_instance->field_value_by_offset(java_lang_String::value_offset_in_bytes()).as_object();
1690 return src_array->as_type_array();
1691 }
1692
1693 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1694 // Log a little info about the transformation
1695 sc->maybe_log_transform();
1696
1697 // pull the JVMState of the allocation into a SafePointNode to serve as
1698 // as a shim for the insertion of the new code.
1699 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1700 uint size = sc->begin()->req();
1701 SafePointNode* map = new SafePointNode(size, jvms);
1702
1703 // copy the control and memory state from the final call into our
1704 // new starting state. This allows any preceeding tests to feed
1705 // into the new section of code.
1706 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1707 map->init_req(i1, sc->end()->in(i1));
1708 }
1709 // blow away old allocation arguments
1710 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1711 map->init_req(i1, C->top());
1712 }
1713 // Copy the rest of the inputs for the JVMState
1714 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1715 map->init_req(i1, sc->begin()->in(i1));
1716 }
1717 // Make sure the memory state is a MergeMem for parsing.
1718 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1719 map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory)));
1720 }
1721
1722 jvms->set_map(map);
1723 map->ensure_stack(jvms, jvms->method()->max_stack());
1724
1725 // disconnect all the old StringBuilder calls from the graph
1726 sc->eliminate_unneeded_control();
1727
1728 // At this point all the old work has been completely removed from
1729 // the graph and the saved JVMState exists at the point where the
1730 // final toString call used to be.
1731 GraphKit kit(jvms);
1732
1733 // There may be uncommon traps which are still using the
1734 // intermediate states and these need to be rewritten to point at
1735 // the JVMState at the beginning of the transformation.
1736 sc->convert_uncommon_traps(kit, jvms);
1737
1738 // Now insert the logic to compute the size of the string followed
1739 // by all the logic to construct array and resulting string.
1740
1741 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1742
1743 // Create a region for the overflow checks to merge into.
1744 int args = MAX2(sc->num_arguments(), 1);
1745 RegionNode* overflow = new RegionNode(args);
1746 kit.gvn().set_type(overflow, Type::CONTROL);
1747
1748 // Create a hook node to hold onto the individual sizes since they
1749 // are need for the copying phase.
1750 Node* string_sizes = new Node(args);
1751
1752 Node* coder = __ intcon(0);
1753 Node* length = __ intcon(0);
1754 // If at least one argument is UTF16 encoded, we can fix the encoding.
1755 bool coder_fixed = false;
1756
1757 if (!CompactStrings) {
1758 // Fix encoding of result string to UTF16
1759 coder_fixed = true;
1760 coder = __ intcon(java_lang_String::CODER_UTF16);
1761 }
1762
1763 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1764 Node* arg = sc->argument(argi);
1765 switch (sc->mode(argi)) {
1766 case StringConcat::IntMode: {
1767 Node* string_size = int_stringSize(kit, arg);
1768
1769 // accumulate total
1770 length = __ AddI(length, string_size);
1771
1772 // Cache this value for the use by int_toString
1773 string_sizes->init_req(argi, string_size);
1774 break;
1775 }
1776 case StringConcat::StringNullCheckMode: {
1777 const Type* type = kit.gvn().type(arg);
1778 assert(type != TypePtr::NULL_PTR, "missing check");
1779 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1780 // Null check with uncommon trap since
1781 // StringBuilder(null) throws exception.
1782 // Use special uncommon trap instead of
1783 // calling normal do_null_check().
1784 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1785 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1786 overflow->add_req(__ IfFalse(iff));
1787 Node* notnull = __ IfTrue(iff);
1788 kit.set_control(notnull); // set control for the cast_not_null
1789 arg = kit.cast_not_null(arg, false);
1790 sc->set_argument(argi, arg);
1791 }
1792 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1793 // Fallthrough to add string length.
1794 }
1795 case StringConcat::StringMode: {
1796 const Type* type = kit.gvn().type(arg);
1797 Node* count = NULL;
1798 Node* arg_coder = NULL;
1799 if (type == TypePtr::NULL_PTR) {
1800 // replace the argument with the null checked version
1801 arg = null_string;
1802 sc->set_argument(argi, arg);
1803 count = kit.load_String_length(arg, true);
1804 arg_coder = kit.load_String_coder(arg, true);
1805 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1806 // s = s != null ? s : "null";
1807 // length = length + (s.count - s.offset);
1808 RegionNode *r = new RegionNode(3);
1809 kit.gvn().set_type(r, Type::CONTROL);
1810 Node *phi = new PhiNode(r, type);
1811 kit.gvn().set_type(phi, phi->bottom_type());
1812 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1813 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1814 Node* notnull = __ IfTrue(iff);
1815 Node* isnull = __ IfFalse(iff);
1816 kit.set_control(notnull); // set control for the cast_not_null
1817 r->init_req(1, notnull);
1818 phi->init_req(1, kit.cast_not_null(arg, false));
1819 r->init_req(2, isnull);
1820 phi->init_req(2, null_string);
1821 kit.set_control(r);
1822 C->record_for_igvn(r);
1823 C->record_for_igvn(phi);
1824 // replace the argument with the null checked version
1825 arg = phi;
1826 sc->set_argument(argi, arg);
1827 count = kit.load_String_length(arg, true);
1828 arg_coder = kit.load_String_coder(arg, true);
1829 } else {
1830 // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP
1831 // kit.control might be a different test, that can be hoisted above the actual nullcheck
1832 // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck.
1833 count = kit.load_String_length(arg, false);
1834 arg_coder = kit.load_String_coder(arg, false);
1835 }
1836
1837 if (arg->is_Con()) {
1838 // Constant string. Get constant coder and length.
1839 jbyte const_coder = get_constant_coder(kit, arg);
1840 int const_length = get_constant_length(kit, arg);
1841 if (const_coder == java_lang_String::CODER_LATIN1) {
1842 // Can be latin1 encoded
1843 arg_coder = __ intcon(const_coder);
1844 count = __ intcon(const_length);
1845 } else {
1846 // Found UTF16 encoded string. Fix result array encoding to UTF16.
1847 coder_fixed = true;
1848 coder = __ intcon(const_coder);
1849 count = __ intcon(const_length / 2);
1850 }
1851 }
1852
1853 if (!coder_fixed) {
1854 coder = __ OrI(coder, arg_coder);
1855 }
1856 length = __ AddI(length, count);
1857 string_sizes->init_req(argi, NULL);
1858 break;
1859 }
1860 case StringConcat::CharMode: {
1861 // one character only
1862 const TypeInt* t = kit.gvn().type(arg)->is_int();
1863 if (!coder_fixed && t->is_con()) {
1864 // Constant char
1865 if (t->get_con() <= 255) {
1866 // Can be latin1 encoded
1867 coder = __ OrI(coder, __ intcon(java_lang_String::CODER_LATIN1));
1868 } else {
1869 // Must be UTF16 encoded. Fix result array encoding to UTF16.
1870 coder_fixed = true;
1871 coder = __ intcon(java_lang_String::CODER_UTF16);
1872 }
1873 } else if (!coder_fixed) {
1874 // Not constant
1875 #undef __
1876 #define __ ideal.
1877 IdealKit ideal(&kit, true, true);
1878 IdealVariable char_coder(ideal); __ declarations_done();
1879 // Check if character can be latin1 encoded
1880 __ if_then(arg, BoolTest::le, __ ConI(0xFF));
1881 __ set(char_coder, __ ConI(java_lang_String::CODER_LATIN1));
1882 __ else_();
1883 __ set(char_coder, __ ConI(java_lang_String::CODER_UTF16));
1884 __ end_if();
1885 kit.sync_kit(ideal);
1886 coder = __ OrI(coder, __ value(char_coder));
1887 #undef __
1888 #define __ kit.
1889 }
1890 length = __ AddI(length, __ intcon(1));
1891 break;
1892 }
1893 default:
1894 ShouldNotReachHere();
1895 }
1896 if (argi > 0) {
1897 // Check that the sum hasn't overflowed
1898 IfNode* iff = kit.create_and_map_if(kit.control(),
1899 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1900 PROB_MIN, COUNT_UNKNOWN);
1901 kit.set_control(__ IfFalse(iff));
1902 overflow->set_req(argi, __ IfTrue(iff));
1903 }
1904 }
1905
1906 {
1907 // Hook
1908 PreserveJVMState pjvms(&kit);
1909 kit.set_control(overflow);
1910 C->record_for_igvn(overflow);
1911 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1912 Deoptimization::Action_make_not_entrant);
1913 }
1914
1915 Node* result;
1916 if (!kit.stopped()) {
1917 assert(CompactStrings || (coder->is_Con() && coder->get_int() == java_lang_String::CODER_UTF16),
1918 "Result string must be UTF16 encoded if CompactStrings is disabled");
1919
1920 Node* dst_array = NULL;
1921 if (sc->num_arguments() == 1 &&
1922 (sc->mode(0) == StringConcat::StringMode ||
1923 sc->mode(0) == StringConcat::StringNullCheckMode)) {
1924 // Handle the case when there is only a single String argument.
1925 // In this case, we can just pull the value from the String itself.
1926 dst_array = kit.load_String_value(sc->argument(0), true);
1927 } else {
1928 // Allocate destination byte array according to coder
1929 dst_array = allocate_byte_array(kit, NULL, __ LShiftI(length, coder));
1930
1931 // Now copy the string representations into the final byte[]
1932 Node* start = __ intcon(0);
1933 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1934 Node* arg = sc->argument(argi);
1935 switch (sc->mode(argi)) {
1936 case StringConcat::IntMode: {
1937 start = int_getChars(kit, arg, dst_array, coder, start, string_sizes->in(argi));
1938 break;
1939 }
1940 case StringConcat::StringNullCheckMode:
1941 case StringConcat::StringMode: {
1942 start = copy_string(kit, arg, dst_array, coder, start);
1943 break;
1944 }
1945 case StringConcat::CharMode: {
1946 start = copy_char(kit, arg, dst_array, coder, start);
1947 break;
1948 }
1949 default:
1950 ShouldNotReachHere();
1951 }
1952 }
1953 }
1954
1955 // If we're not reusing an existing String allocation then allocate one here.
1956 result = sc->string_alloc();
1957 if (result == NULL) {
1958 PreserveReexecuteState preexecs(&kit);
1959 // The original jvms is for an allocation of either a String or
1960 // StringBuffer so no stack adjustment is necessary for proper
1961 // reexecution.
1962 kit.jvms()->set_should_reexecute(true);
1963 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1964 }
1965
1966 // Initialize the string
1967 kit.store_String_value(result, dst_array);
1968 kit.store_String_coder(result, coder);
1969
1970 // The value field is final. Emit a barrier here to ensure that the effect
1971 // of the initialization is committed to memory before any code publishes
1972 // a reference to the newly constructed object (see Parse::do_exits()).
1973 assert(AllocateNode::Ideal_allocation(result, _gvn) != NULL, "should be newly allocated");
1974 kit.insert_mem_bar(Op_MemBarRelease, result);
1975 } else {
1976 result = C->top();
1977 }
1978 // hook up the outgoing control and result
1979 kit.replace_call(sc->end(), result);
1980
1981 // Unhook any hook nodes
1982 string_sizes->disconnect_inputs(NULL, C);
1983 sc->cleanup();
1984 }