1 /*
2 * Copyright (c) 2009, 2025, 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 "ci/ciSymbols.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "compiler/compileLog.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/graphKit.hpp"
30 #include "opto/idealKit.hpp"
31 #include "opto/rootnode.hpp"
32 #include "opto/runtime.hpp"
33 #include "opto/stringopts.hpp"
34 #include "runtime/atomic.hpp"
35 #include "runtime/stubRoutines.hpp"
36
37 #define __ kit.
38
39 class StringConcat : public ResourceObj {
40 private:
41 PhaseStringOpts* _stringopts;
42 AllocateNode* _begin; // The allocation the begins the pattern
43 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
44 // SB.toString or String.<init>(SB.toString)
45 bool _multiple; // indicates this is a fusion of two or more
46 // separate StringBuilders
47
48 Node* _arguments; // The list of arguments to be concatenated
49 GrowableArray<int> _mode; // into a String along with a mode flag
50 // indicating how to treat the value.
51 Node_List _constructors; // List of constructors (many in case of stacked concat)
52 Node_List _control; // List of control nodes that will be deleted
53 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
54 // to restart at the initial JVMState.
55
56 public:
57 // Mode for converting arguments to Strings
58 enum {
59 StringMode,
60 IntMode,
61 CharMode,
62 StringNullCheckMode,
63 NegativeIntCheckMode
64 };
65
66 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
67 _stringopts(stringopts),
68 _begin(nullptr),
69 _end(end),
70 _multiple(false) {
71 _arguments = new Node(1);
72 _arguments->del_req(0);
73 }
74
75 bool validate_mem_flow();
76 bool validate_control_flow();
77
78 StringConcat* merge(StringConcat* other, Node* arg);
79
80 void set_allocation(AllocateNode* alloc) {
81 _begin = alloc;
82 }
83
84 void append(Node* value, int mode) {
85 _arguments->add_req(value);
86 _mode.append(mode);
87 }
88 void push(Node* value, int mode) {
89 _arguments->ins_req(0, value);
90 _mode.insert_before(0, mode);
91 }
92
93 void push_string(Node* value) {
94 push(value, StringMode);
95 }
96
97 void push_string_null_check(Node* value) {
98 push(value, StringNullCheckMode);
99 }
100
101 void push_negative_int_check(Node* value) {
102 push(value, NegativeIntCheckMode);
103 }
104
105 void push_int(Node* value) {
106 push(value, IntMode);
107 }
108
109 void push_char(Node* value) {
110 push(value, CharMode);
111 }
112
113 static bool is_SB_toString(Node* call) {
114 if (call->is_CallStaticJava()) {
115 CallStaticJavaNode* csj = call->as_CallStaticJava();
116 ciMethod* m = csj->method();
117 if (m != nullptr &&
118 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
119 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
120 return true;
121 }
122 }
123 return false;
124 }
125
126 static Node* skip_string_null_check(Node* value) {
127 // Look for a diamond shaped Null check of toString() result
128 // (could be code from String.valueOf()):
129 // (Proj == nullptr) ? "null":"CastPP(Proj)#Notnull
130 if (value->is_Phi()) {
131 int true_path = value->as_Phi()->is_diamond_phi();
132 if (true_path != 0) {
133 // phi->region->if_proj->ifnode->bool
134 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
135 Node* cmp = b->in(1);
136 Node* v1 = cmp->in(1);
137 Node* v2 = cmp->in(2);
138 // Null check of the return of toString which can simply be skipped.
139 if (b->_test._test == BoolTest::ne &&
140 v2->bottom_type() == TypePtr::NULL_PTR &&
141 value->in(true_path)->Opcode() == Op_CastPP &&
142 value->in(true_path)->in(1) == v1 &&
143 v1->is_Proj() && is_SB_toString(v1->in(0))) {
144 return v1;
145 }
146 }
147 }
148 return value;
149 }
150
151 Node* argument(int i) {
152 return _arguments->in(i);
153 }
154 Node* argument_uncast(int i) {
155 Node* arg = argument(i);
156 int amode = mode(i);
157 if (amode == StringConcat::StringMode ||
158 amode == StringConcat::StringNullCheckMode) {
159 arg = skip_string_null_check(arg);
160 }
161 return arg;
162 }
163 void set_argument(int i, Node* value) {
164 _arguments->set_req(i, value);
165 }
166 int num_arguments() {
167 return _mode.length();
168 }
169 int mode(int i) {
170 return _mode.at(i);
171 }
172 void add_control(Node* ctrl) {
173 assert(!_control.contains(ctrl), "only push once");
174 _control.push(ctrl);
175 }
176 void add_constructor(Node* init) {
177 assert(!_constructors.contains(init), "only push once");
178 _constructors.push(init);
179 }
180 CallStaticJavaNode* end() { return _end; }
181 AllocateNode* begin() { return _begin; }
182
183 void eliminate_unneeded_control();
184 void eliminate_initialize(InitializeNode* init);
185 void eliminate_call(CallNode* call);
186
187 void maybe_log_transform() {
188 CompileLog* log = _stringopts->C->log();
189 if (log != nullptr) {
190 log->head("replace_string_concat arguments='%d' multiple='%d'", num_arguments(), _multiple);
191 JVMState* p = _begin->jvms();
192 while (p != nullptr) {
193 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
194 p = p->caller();
195 }
196 log->tail("replace_string_concat");
197 }
198 }
199
200 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
201 for (uint u = 0; u < _uncommon_traps.size(); u++) {
202 Node* uct = _uncommon_traps.at(u);
203
204 // Build a new call using the jvms state of the allocate
205 address call_addr = OptoRuntime::uncommon_trap_blob()->entry_point();
206 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
207 const TypePtr* no_memory_effects = nullptr;
208 Compile* C = _stringopts->C;
209 CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
210 no_memory_effects);
211 for (int e = 0; e < TypeFunc::Parms; e++) {
212 call->init_req(e, uct->in(e));
213 }
214 // Set the trap request to record intrinsic failure if this trap
215 // is taken too many times. Ideally we would handle then traps by
216 // doing the original bookkeeping in the MDO so that if it caused
217 // the code to be thrown out we could still recompile and use the
218 // optimization. Failing the uncommon traps doesn't really mean
219 // that the optimization is a bad idea but there's no other way to
220 // do the MDO updates currently.
221 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
222 Deoptimization::Action_make_not_entrant);
223 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
224 kit.add_safepoint_edges(call);
225
226 _stringopts->gvn()->transform(call);
227 C->gvn_replace_by(uct, call);
228 uct->disconnect_inputs(C);
229 }
230 }
231
232 void cleanup() {
233 // disconnect the hook node
234 _arguments->disconnect_inputs(_stringopts->C);
235 }
236 };
237
238
239 void StringConcat::eliminate_unneeded_control() {
240 for (uint i = 0; i < _control.size(); i++) {
241 Node* n = _control.at(i);
242 if (n->is_Allocate()) {
243 eliminate_initialize(n->as_Allocate()->initialization());
244 }
245 if (n->is_Call()) {
246 if (n != _end) {
247 eliminate_call(n->as_Call());
248 }
249 } else if (n->is_IfTrue()) {
250 Compile* C = _stringopts->C;
251 C->gvn_replace_by(n, n->in(0)->in(0));
252 // get rid of the other projection
253 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
254 } else if (n->is_Region()) {
255 Node* iff = n->in(1)->in(0);
256 assert(n->req() == 3 && n->in(2)->in(0) == iff, "not a diamond");
257 assert(iff->is_If(), "no if for the diamond");
258 Node* bol = iff->in(1);
259 assert(bol->is_Bool(), "unexpected if shape");
260 Node* cmp = bol->in(1);
261 assert(cmp->is_Cmp(), "unexpected if shape");
262 if (cmp->in(1)->is_top() || cmp->in(2)->is_top()) {
263 // This region should lose its Phis. They are removed either in PhaseRemoveUseless (for data phis) or in IGVN
264 // (for memory phis). During IGVN, there is a chance that the If folds to top before the Region is processed
265 // which then causes a reachable part of the graph to become dead. To prevent this, set the boolean input of
266 // the If to a constant to nicely let the diamond Region/If fold away.
267 Compile* C = _stringopts->C;
268 C->gvn_replace_by(iff->in(1), _stringopts->gvn()->intcon(0));
269 }
270 }
271 }
272 }
273
274
275 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
276 StringConcat* result = new StringConcat(_stringopts, _end);
277 for (uint x = 0; x < _control.size(); x++) {
278 Node* n = _control.at(x);
279 if (n->is_Call()) {
280 result->_control.push(n);
281 }
282 }
283 for (uint x = 0; x < other->_control.size(); x++) {
284 Node* n = other->_control.at(x);
285 if (n->is_Call()) {
286 result->_control.push(n);
287 }
288 }
289 assert(result->_control.contains(other->_end), "what?");
290 assert(result->_control.contains(_begin), "what?");
291 for (int x = 0; x < num_arguments(); x++) {
292 Node* argx = argument_uncast(x);
293 if (argx == arg) {
294 // replace the toString result with the all the arguments that
295 // made up the other StringConcat
296 for (int y = 0; y < other->num_arguments(); y++) {
297 result->append(other->argument(y), other->mode(y));
298 }
299 } else {
300 result->append(argx, mode(x));
301 }
302 }
303 result->set_allocation(other->_begin);
304 for (uint i = 0; i < _constructors.size(); i++) {
305 result->add_constructor(_constructors.at(i));
306 }
307 for (uint i = 0; i < other->_constructors.size(); i++) {
308 result->add_constructor(other->_constructors.at(i));
309 }
310 result->_multiple = true;
311 return result;
312 }
313
314
315 void StringConcat::eliminate_call(CallNode* call) {
316 Compile* C = _stringopts->C;
317 CallProjections projs;
318 call->extract_projections(&projs, false);
319 if (projs.fallthrough_catchproj != nullptr) {
320 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
321 }
322 if (projs.fallthrough_memproj != nullptr) {
323 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
324 }
325 if (projs.catchall_memproj != nullptr) {
326 C->gvn_replace_by(projs.catchall_memproj, C->top());
327 }
328 if (projs.fallthrough_ioproj != nullptr) {
329 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
330 }
331 if (projs.catchall_ioproj != nullptr) {
332 C->gvn_replace_by(projs.catchall_ioproj, C->top());
333 }
334 if (projs.catchall_catchproj != nullptr) {
335 // EA can't cope with the partially collapsed graph this
336 // creates so put it on the worklist to be collapsed later.
337 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
338 Node *use = i.get();
339 int opc = use->Opcode();
340 if (opc == Op_CreateEx || opc == Op_Region) {
341 _stringopts->record_dead_node(use);
342 }
343 }
344 C->gvn_replace_by(projs.catchall_catchproj, C->top());
345 }
346 if (projs.resproj != nullptr) {
347 C->gvn_replace_by(projs.resproj, C->top());
348 }
349 C->gvn_replace_by(call, C->top());
350 }
351
352 void StringConcat::eliminate_initialize(InitializeNode* init) {
353 Compile* C = _stringopts->C;
354
355 // Eliminate Initialize node.
356 assert(init->outcnt() <= 2, "only a control and memory projection expected");
357 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
358 Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
359 if (ctrl_proj != nullptr) {
360 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
361 }
362 Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
363 if (mem_proj != nullptr) {
364 Node *mem = init->in(TypeFunc::Memory);
365 C->gvn_replace_by(mem_proj, mem);
366 }
367 C->gvn_replace_by(init, C->top());
368 init->disconnect_inputs(C);
369 }
370
371 Node_List PhaseStringOpts::collect_toString_calls() {
372 Node_List string_calls;
373 Node_List worklist;
374
375 _visited.clear();
376
377 // Prime the worklist
378 for (uint i = 1; i < C->root()->len(); i++) {
379 Node* n = C->root()->in(i);
380 if (n != nullptr && !_visited.test_set(n->_idx)) {
381 worklist.push(n);
382 }
383 }
384
385 uint encountered = 0;
386 while (worklist.size() > 0) {
387 Node* ctrl = worklist.pop();
388 if (StringConcat::is_SB_toString(ctrl)) {
389 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
390 string_calls.push(csj);
391 encountered++;
392 }
393 if (ctrl->in(0) != nullptr && !_visited.test_set(ctrl->in(0)->_idx)) {
394 worklist.push(ctrl->in(0));
395 }
396 if (ctrl->is_Region()) {
397 for (uint i = 1; i < ctrl->len(); i++) {
398 if (ctrl->in(i) != nullptr && !_visited.test_set(ctrl->in(i)->_idx)) {
399 worklist.push(ctrl->in(i));
400 }
401 }
402 }
403 }
404 #ifndef PRODUCT
405 Atomic::add(&_stropts_total, encountered);
406 #endif
407 return string_calls;
408 }
409
410 // Recognize a fluent-chain of StringBuilder/Buffer. They are either explicit usages
411 // of them or the legacy bytecodes of string concatenation prior to JEP-280. eg.
412 //
413 // String result = new StringBuilder()
414 // .append("foo")
415 // .append("bar")
416 // .append(123)
417 // .toString(); // "foobar123"
418 //
419 // PS: Only a certain subset of constructor and append methods are acceptable.
420 // The criterion is that the length of argument is easy to work out in this phrase.
421 // It will drop complex cases such as Object.
422 //
423 // Since it walks along the receivers of fluent-chain, it will give up if the codeshape is
424 // not "fluent" enough. eg.
425 // StringBuilder sb = new StringBuilder();
426 // sb.append("foo");
427 // sb.toString();
428 //
429 // The receiver of toString method is the result of Allocation Node(CheckCastPP).
430 // The append method is overlooked. It will fail at validate_control_flow() test.
431 //
432 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
433 ciMethod* m = call->method();
434 ciSymbol* string_sig;
435 ciSymbol* int_sig;
436 ciSymbol* char_sig;
437 if (m->holder() == C->env()->StringBuilder_klass()) {
438 string_sig = ciSymbols::String_StringBuilder_signature();
439 int_sig = ciSymbols::int_StringBuilder_signature();
440 char_sig = ciSymbols::char_StringBuilder_signature();
441 } else if (m->holder() == C->env()->StringBuffer_klass()) {
442 string_sig = ciSymbols::String_StringBuffer_signature();
443 int_sig = ciSymbols::int_StringBuffer_signature();
444 char_sig = ciSymbols::char_StringBuffer_signature();
445 } else {
446 return nullptr;
447 }
448 #ifndef PRODUCT
449 if (PrintOptimizeStringConcat) {
450 tty->print("considering toString call in ");
451 call->jvms()->dump_spec(tty); tty->cr();
452 }
453 #endif
454
455 StringConcat* sc = new StringConcat(this, call);
456 AllocateNode* alloc = nullptr;
457
458 // possible opportunity for StringBuilder fusion
459 CallStaticJavaNode* cnode = call;
460 while (cnode) {
461 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
462 if (recv->is_Proj()) {
463 recv = recv->in(0);
464 }
465 cnode = recv->isa_CallStaticJava();
466 if (cnode == nullptr) {
467 alloc = recv->isa_Allocate();
468 if (alloc == nullptr) {
469 break;
470 }
471 // Find the constructor call
472 Node* result = alloc->result_cast();
473 if (result == nullptr || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
474 // strange looking allocation
475 #ifndef PRODUCT
476 if (PrintOptimizeStringConcat) {
477 tty->print("giving up because allocation looks strange ");
478 alloc->jvms()->dump_spec(tty); tty->cr();
479 }
480 #endif
481 break;
482 }
483 Node* constructor = nullptr;
484 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
485 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
486 if (use != nullptr &&
487 use->method() != nullptr &&
488 !use->method()->is_static() &&
489 use->method()->name() == ciSymbols::object_initializer_name() &&
490 use->method()->holder() == m->holder()) {
491 // Matched the constructor.
492 ciSymbol* sig = use->method()->signature()->as_symbol();
493 if (sig == ciSymbols::void_method_signature() ||
494 sig == ciSymbols::int_void_signature() ||
495 sig == ciSymbols::string_void_signature()) {
496 if (sig == ciSymbols::string_void_signature()) {
497 // StringBuilder(String) so pick this up as the first argument
498 assert(use->in(TypeFunc::Parms + 1) != nullptr, "what?");
499 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
500 if (type == TypePtr::NULL_PTR) {
501 // StringBuilder(null) throws exception.
502 #ifndef PRODUCT
503 if (PrintOptimizeStringConcat) {
504 tty->print("giving up because StringBuilder(null) throws exception");
505 alloc->jvms()->dump_spec(tty);
506 tty->cr();
507 }
508 #endif
509 return nullptr;
510 }
511 // StringBuilder(str) argument needs null check.
512 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
513 } else if (sig == ciSymbols::int_void_signature()) {
514 // StringBuilder(int) case.
515 Node* parm = use->in(TypeFunc::Parms + 1);
516 assert(parm != nullptr, "must exist");
517 const TypeInt* type = _gvn->type(parm)->is_int();
518 if (type->_hi < 0) {
519 // Initial capacity argument is always negative in which case StringBuilder(int) throws
520 // a NegativeArraySizeException. Bail out from string opts.
521 #ifndef PRODUCT
522 if (PrintOptimizeStringConcat) {
523 tty->print("giving up because a negative argument is passed to StringBuilder(int) which "
524 "throws a NegativeArraySizeException");
525 alloc->jvms()->dump_spec(tty);
526 tty->cr();
527 }
528 #endif
529 return nullptr;
530 } else if (type->_lo < 0) {
531 // Argument could be negative: We need a runtime check to throw NegativeArraySizeException in that case.
532 sc->push_negative_int_check(parm);
533 }
534 }
535 // The int variant takes an initial size for the backing
536 // array so just treat it like the void version.
537 constructor = use;
538 } else {
539 #ifndef PRODUCT
540 if (PrintOptimizeStringConcat) {
541 tty->print("unexpected constructor signature: %s", sig->as_utf8());
542 }
543 #endif
544 }
545 break;
546 }
547 }
548 if (constructor == nullptr) {
549 // couldn't find constructor
550 #ifndef PRODUCT
551 if (PrintOptimizeStringConcat) {
552 tty->print("giving up because couldn't find constructor ");
553 alloc->jvms()->dump_spec(tty); tty->cr();
554 }
555 #endif
556 break;
557 }
558
559 // Walked all the way back and found the constructor call so see
560 // if this call converted into a direct string concatenation.
561 sc->add_control(call);
562 sc->add_control(constructor);
563 sc->add_control(alloc);
564 sc->set_allocation(alloc);
565 sc->add_constructor(constructor);
566 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
567 return sc;
568 } else {
569 return nullptr;
570 }
571 } else if (cnode->method() == nullptr) {
572 break;
573 } else if (!cnode->method()->is_static() &&
574 cnode->method()->holder() == m->holder() &&
575 cnode->method()->name() == ciSymbols::append_name() &&
576 (cnode->method()->signature()->as_symbol() == string_sig ||
577 cnode->method()->signature()->as_symbol() == char_sig ||
578 cnode->method()->signature()->as_symbol() == int_sig)) {
579 sc->add_control(cnode);
580 Node* arg = cnode->in(TypeFunc::Parms + 1);
581 if (arg == nullptr || arg->is_top()) {
582 #ifndef PRODUCT
583 if (PrintOptimizeStringConcat) {
584 tty->print("giving up because the call is effectively dead");
585 cnode->jvms()->dump_spec(tty); tty->cr();
586 }
587 #endif
588 break;
589 }
590 if (cnode->method()->signature()->as_symbol() == int_sig) {
591 sc->push_int(arg);
592 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
593 sc->push_char(arg);
594 } else {
595 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
596 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
597 if (csj->method() != nullptr &&
598 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
599 arg->outcnt() == 1) {
600 // _control is the list of StringBuilder calls nodes which
601 // will be replaced by new String code after this optimization.
602 // Integer::toString() call is not part of StringBuilder calls
603 // chain. It could be eliminated only if its result is used
604 // only by this SB calls chain.
605 // Another limitation: it should be used only once because
606 // it is unknown that it is used only by this SB calls chain
607 // until all related SB calls nodes are collected.
608 assert(arg->unique_out() == cnode, "sanity");
609 sc->add_control(csj);
610 sc->push_int(csj->in(TypeFunc::Parms));
611 continue;
612 }
613 }
614 sc->push_string(arg);
615 }
616 continue;
617 } else {
618 // some unhandled signature
619 #ifndef PRODUCT
620 if (PrintOptimizeStringConcat) {
621 tty->print("giving up because encountered unexpected signature ");
622 cnode->tf()->dump(); tty->cr();
623 cnode->in(TypeFunc::Parms + 1)->dump();
624 }
625 #endif
626 break;
627 }
628 }
629 return nullptr;
630 }
631
632
633 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn):
634 Phase(StringOpts),
635 _gvn(gvn) {
636
637 assert(OptimizeStringConcat, "shouldn't be here");
638
639 // Collect the types needed to talk about the various slices of memory
640 byte_adr_idx = C->get_alias_index(TypeAryPtr::BYTES);
641
642 // For each locally allocated StringBuffer see if the usages can be
643 // collapsed into a single String construction.
644
645 // Run through the list of allocation looking for SB.toString to see
646 // if it's possible to fuse the usage of the SB into a single String
647 // construction.
648 GrowableArray<StringConcat*> concats;
649 Node_List toStrings = collect_toString_calls();
650 while (toStrings.size() > 0) {
651 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
652 if (sc != nullptr) {
653 concats.push(sc);
654 }
655 }
656
657 // try to coalesce separate concats
658 restart:
659 for (int c = 0; c < concats.length(); c++) {
660 StringConcat* sc = concats.at(c);
661 for (int i = 0; i < sc->num_arguments(); i++) {
662 Node* arg = sc->argument_uncast(i);
663 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
664 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
665 for (int o = 0; o < concats.length(); o++) {
666 if (c == o) continue;
667 StringConcat* other = concats.at(o);
668 if (other->end() == csj) {
669 #ifndef PRODUCT
670 if (PrintOptimizeStringConcat) {
671 tty->print_cr("considering stacked concats");
672 }
673 #endif
674
675 StringConcat* merged = sc->merge(other, arg);
676 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
677 #ifndef PRODUCT
678 Atomic::inc(&_stropts_merged);
679 if (PrintOptimizeStringConcat) {
680 tty->print_cr("stacking would succeed");
681 }
682 #endif
683 if (c < o) {
684 concats.remove_at(o);
685 concats.at_put(c, merged);
686 } else {
687 concats.remove_at(c);
688 concats.at_put(o, merged);
689 }
690 goto restart;
691 } else {
692 #ifndef PRODUCT
693 if (PrintOptimizeStringConcat) {
694 tty->print_cr("stacking would fail");
695 }
696 #endif
697 }
698 }
699 }
700 }
701 }
702 }
703
704
705 for (int c = 0; c < concats.length(); c++) {
706 StringConcat* sc = concats.at(c);
707 replace_string_concat(sc);
708 }
709
710 remove_dead_nodes();
711 }
712
713 void PhaseStringOpts::record_dead_node(Node* dead) {
714 dead_worklist.push(dead);
715 }
716
717 void PhaseStringOpts::remove_dead_nodes() {
718 // Delete any dead nodes to make things clean enough that escape
719 // analysis doesn't get unhappy.
720 while (dead_worklist.size() > 0) {
721 Node* use = dead_worklist.pop();
722 int opc = use->Opcode();
723 switch (opc) {
724 case Op_Region: {
725 uint i = 1;
726 for (i = 1; i < use->req(); i++) {
727 if (use->in(i) != C->top()) {
728 break;
729 }
730 }
731 if (i >= use->req()) {
732 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
733 Node* m = i.get();
734 if (m->is_Phi()) {
735 dead_worklist.push(m);
736 }
737 }
738 C->gvn_replace_by(use, C->top());
739 }
740 break;
741 }
742 case Op_AddP:
743 case Op_CreateEx: {
744 // Recursively clean up references to CreateEx so EA doesn't
745 // get unhappy about the partially collapsed graph.
746 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
747 Node* m = i.get();
748 if (m->is_AddP()) {
749 dead_worklist.push(m);
750 }
751 }
752 C->gvn_replace_by(use, C->top());
753 break;
754 }
755 case Op_Phi:
756 if (use->in(0) == C->top()) {
757 C->gvn_replace_by(use, C->top());
758 }
759 break;
760 }
761 }
762 }
763
764
765 bool StringConcat::validate_mem_flow() {
766 Compile* C = _stringopts->C;
767
768 for (uint i = 0; i < _control.size(); i++) {
769 #ifndef PRODUCT
770 Node_List path;
771 #endif
772 Node* curr = _control.at(i);
773 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
774 // Now here's the main invariant in our case:
775 // For memory between the constructor, and appends, and toString we should only see bottom memory,
776 // produced by the previous call we know about.
777 if (!_constructors.contains(curr)) {
778 NOT_PRODUCT(path.push(curr);)
779 Node* mem = curr->in(TypeFunc::Memory);
780 assert(mem != nullptr, "calls should have memory edge");
781 assert(!mem->is_Phi(), "should be handled by control flow validation");
782 NOT_PRODUCT(path.push(mem);)
783 while (mem->is_MergeMem()) {
784 for (uint i = 1; i < mem->req(); i++) {
785 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
786 #ifndef PRODUCT
787 if (PrintOptimizeStringConcat) {
788 tty->print("fusion has incorrect memory flow (side effects) for ");
789 _begin->jvms()->dump_spec(tty); tty->cr();
790 path.dump();
791 }
792 #endif
793 return false;
794 }
795 }
796 // skip through a potential MergeMem chain, linked through Bot
797 mem = mem->in(Compile::AliasIdxBot);
798 NOT_PRODUCT(path.push(mem);)
799 }
800 // now let it fall through, and see if we have a projection
801 if (mem->is_Proj()) {
802 // Should point to a previous known call
803 Node *prev = mem->in(0);
804 NOT_PRODUCT(path.push(prev);)
805 if (!prev->is_Call() || !_control.contains(prev)) {
806 #ifndef PRODUCT
807 if (PrintOptimizeStringConcat) {
808 tty->print("fusion has incorrect memory flow (unknown call) for ");
809 _begin->jvms()->dump_spec(tty); tty->cr();
810 path.dump();
811 }
812 #endif
813 return false;
814 }
815 } else {
816 assert(mem->is_Store() || mem->is_LoadStore(), "unexpected node type: %s", mem->Name());
817 #ifndef PRODUCT
818 if (PrintOptimizeStringConcat) {
819 tty->print("fusion has incorrect memory flow (unexpected source) for ");
820 _begin->jvms()->dump_spec(tty); tty->cr();
821 path.dump();
822 }
823 #endif
824 return false;
825 }
826 } else {
827 // For memory that feeds into constructors it's more complicated.
828 // However the advantage is that any side effect that happens between the Allocate/Initialize and
829 // the constructor will have to be control-dependent on Initialize.
830 // So we actually don't have to do anything, since it's going to be caught by the control flow
831 // analysis.
832 #ifdef ASSERT
833 // Do a quick verification of the control pattern between the constructor and the initialize node
834 assert(curr->is_Call(), "constructor should be a call");
835 // Go up the control starting from the constructor call
836 Node* ctrl = curr->in(0);
837 IfNode* iff = nullptr;
838 RegionNode* copy = nullptr;
839
840 while (true) {
841 // skip known check patterns
842 if (ctrl->is_Region()) {
843 if (ctrl->as_Region()->is_copy()) {
844 copy = ctrl->as_Region();
845 ctrl = copy->is_copy();
846 } else { // a cast
847 assert(ctrl->req() == 3 &&
848 ctrl->in(1) != nullptr && ctrl->in(1)->is_Proj() &&
849 ctrl->in(2) != nullptr && ctrl->in(2)->is_Proj() &&
850 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
851 ctrl->in(1)->in(0) != nullptr && ctrl->in(1)->in(0)->is_If(),
852 "must be a simple diamond");
853 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
854 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
855 Node* use = i.get();
856 assert(use == ctrl || use->is_ConstraintCast(),
857 "unexpected user: %s", use->Name());
858 }
859
860 iff = ctrl->in(1)->in(0)->as_If();
861 ctrl = iff->in(0);
862 }
863 } else if (ctrl->is_IfTrue()) { // null checks, class checks
864 iff = ctrl->in(0)->as_If();
865 // Verify that the other arm is an uncommon trap
866 Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
867 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
868 assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommon trap");
869 ctrl = iff->in(0);
870 } else {
871 break;
872 }
873 }
874
875 assert(ctrl->is_Proj(), "must be a projection");
876 assert(ctrl->in(0)->is_Initialize(), "should be initialize");
877 for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) {
878 Node* use = i.get();
879 assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(),
880 "unexpected user: %s", use->Name());
881 }
882 #endif // ASSERT
883 }
884 }
885 }
886
887 #ifndef PRODUCT
888 if (PrintOptimizeStringConcat) {
889 tty->print("fusion has correct memory flow for ");
890 _begin->jvms()->dump_spec(tty); tty->cr();
891 tty->cr();
892 }
893 #endif
894 return true;
895 }
896
897 bool StringConcat::validate_control_flow() {
898 // We found all the calls and arguments now lets see if it's
899 // safe to transform the graph as we would expect.
900
901 // Check to see if this resulted in too many uncommon traps previously
902 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
903 Deoptimization::Reason_intrinsic)) {
904 return false;
905 }
906
907 // Walk backwards over the control flow from toString to the
908 // allocation and make sure all the control flow is ok. This
909 // means it's either going to be eliminated once the calls are
910 // removed or it can safely be transformed into an uncommon
911 // trap.
912
913 int null_check_count = 0;
914 Unique_Node_List ctrl_path;
915
916 assert(_control.contains(_begin), "missing");
917 assert(_control.contains(_end), "missing");
918
919 // Collect the nodes that we know about and will eliminate into ctrl_path
920 for (uint i = 0; i < _control.size(); i++) {
921 // Push the call and it's control projection
922 Node* n = _control.at(i);
923 if (n->is_Allocate()) {
924 AllocateNode* an = n->as_Allocate();
925 InitializeNode* init = an->initialization();
926 ctrl_path.push(init);
927 ctrl_path.push(init->as_Multi()->proj_out(0));
928 }
929 if (n->is_Call()) {
930 CallNode* cn = n->as_Call();
931 ctrl_path.push(cn);
932 ctrl_path.push(cn->proj_out(0));
933 ctrl_path.push(cn->proj_out(0)->unique_out());
934 Node* catchproj = cn->proj_out(0)->unique_out()->as_Catch()->proj_out_or_null(0);
935 if (catchproj != nullptr) {
936 ctrl_path.push(catchproj);
937 }
938 } else {
939 ShouldNotReachHere();
940 }
941 }
942
943 // Skip backwards through the control checking for unexpected control flow
944 Node* ptr = _end;
945 bool fail = false;
946 while (ptr != _begin) {
947 if (ptr->is_Call() && ctrl_path.member(ptr)) {
948 ptr = ptr->in(0);
949 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
950 ptr = ptr->in(0)->in(0)->in(0);
951 assert(ctrl_path.member(ptr), "should be a known piece of control");
952 } else if (ptr->is_IfTrue()) {
953 IfNode* iff = ptr->in(0)->as_If();
954 BoolNode* b = iff->in(1)->isa_Bool();
955
956 if (b == nullptr) {
957 #ifndef PRODUCT
958 if (PrintOptimizeStringConcat) {
959 tty->print_cr("unexpected input to IfNode");
960 iff->in(1)->dump();
961 tty->cr();
962 }
963 #endif
964 fail = true;
965 break;
966 }
967
968 Node* cmp = b->in(1);
969 Node* v1 = cmp->in(1);
970 Node* v2 = cmp->in(2);
971 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
972
973 // Null check of the return of append which can simply be eliminated
974 if (b->_test._test == BoolTest::ne &&
975 v2->bottom_type() == TypePtr::NULL_PTR &&
976 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
977 // null check of the return value of the append
978 null_check_count++;
979 if (otherproj->outcnt() == 1) {
980 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
981 if (call != nullptr && call->_name != nullptr && strcmp(call->_name, "uncommon_trap") == 0) {
982 ctrl_path.push(call);
983 }
984 }
985 _control.push(ptr);
986 ptr = ptr->in(0)->in(0);
987 continue;
988 }
989
990 // A test which leads to an uncommon trap which should be safe.
991 // Later this trap will be converted into a trap that restarts
992 // at the beginning.
993 if (otherproj->outcnt() == 1) {
994 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
995 if (call != nullptr && call->_name != nullptr && strcmp(call->_name, "uncommon_trap") == 0) {
996 // control flow leads to uct so should be ok
997 _uncommon_traps.push(call);
998 ctrl_path.push(call);
999 ptr = ptr->in(0)->in(0);
1000 continue;
1001 }
1002 }
1003
1004 #ifndef PRODUCT
1005 // Some unexpected control flow we don't know how to handle.
1006 if (PrintOptimizeStringConcat) {
1007 tty->print_cr("failing with unknown test");
1008 b->dump();
1009 cmp->dump();
1010 v1->dump();
1011 v2->dump();
1012 tty->cr();
1013 }
1014 #endif
1015 fail = true;
1016 break;
1017 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
1018 // Check for side effect between Initialize and the constructor
1019 for (SimpleDUIterator iter(ptr); iter.has_next(); iter.next()) {
1020 Node* use = iter.get();
1021 if (!use->is_CFG() && !use->is_CheckCastPP() && !use->is_Load()) {
1022 #ifndef PRODUCT
1023 if (PrintOptimizeStringConcat) {
1024 tty->print_cr("unexpected control use of Initialize");
1025 ptr->in(0)->dump(); // Initialize node
1026 use->dump(1);
1027 }
1028 #endif
1029 fail = true;
1030 break;
1031 }
1032 }
1033 ptr = ptr->in(0)->in(0);
1034 } else if (ptr->is_Region()) {
1035 Node* copy = ptr->as_Region()->is_copy();
1036 if (copy != nullptr) {
1037 ptr = copy;
1038 continue;
1039 }
1040 if (ptr->req() == 3 &&
1041 ptr->in(1) != nullptr && ptr->in(1)->is_Proj() &&
1042 ptr->in(2) != nullptr && ptr->in(2)->is_Proj() &&
1043 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
1044 ptr->in(1)->in(0) != nullptr && ptr->in(1)->in(0)->is_If()) {
1045 // Simple diamond.
1046 // XXX should check for possibly merging stores. simple data merges are ok.
1047 // The IGVN will make this simple diamond go away when it
1048 // transforms the Region. Make sure it sees it.
1049 Compile::current()->record_for_igvn(ptr);
1050 _control.push(ptr);
1051 ptr = ptr->in(1)->in(0)->in(0);
1052 continue;
1053 }
1054 #ifndef PRODUCT
1055 if (PrintOptimizeStringConcat) {
1056 tty->print_cr("fusion would fail for region");
1057 _begin->dump();
1058 ptr->dump(2);
1059 }
1060 #endif
1061 fail = true;
1062 break;
1063 } else {
1064 // other unknown control
1065 if (!fail) {
1066 #ifndef PRODUCT
1067 if (PrintOptimizeStringConcat) {
1068 tty->print_cr("fusion would fail for");
1069 _begin->dump();
1070 }
1071 #endif
1072 fail = true;
1073 }
1074 #ifndef PRODUCT
1075 if (PrintOptimizeStringConcat) {
1076 ptr->dump();
1077 }
1078 #endif
1079 ptr = ptr->in(0);
1080 }
1081 }
1082 #ifndef PRODUCT
1083 if (PrintOptimizeStringConcat && fail) {
1084 tty->cr();
1085 }
1086 #endif
1087 if (fail) return !fail;
1088
1089 // Validate that all these results produced are contained within
1090 // this cluster of objects. First collect all the results produced
1091 // by calls in the region.
1092 _stringopts->_visited.clear();
1093 Node_List worklist;
1094 Node* final_result = _end->proj_out_or_null(TypeFunc::Parms);
1095 for (uint i = 0; i < _control.size(); i++) {
1096 CallNode* cnode = _control.at(i)->isa_Call();
1097 if (cnode != nullptr) {
1098 _stringopts->_visited.test_set(cnode->_idx);
1099 }
1100 Node* result = cnode != nullptr ? cnode->proj_out_or_null(TypeFunc::Parms) : nullptr;
1101 if (result != nullptr && result != final_result) {
1102 worklist.push(result);
1103 }
1104 }
1105
1106 Node* last_result = nullptr;
1107 while (worklist.size() > 0) {
1108 Node* result = worklist.pop();
1109 if (_stringopts->_visited.test_set(result->_idx))
1110 continue;
1111 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
1112 Node *use = i.get();
1113 if (ctrl_path.member(use)) {
1114 // already checked this
1115 continue;
1116 }
1117 int opc = use->Opcode();
1118 if (opc == Op_CmpP || opc == Op_Node) {
1119 ctrl_path.push(use);
1120 continue;
1121 }
1122 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
1123 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
1124 worklist.push(j.get());
1125 }
1126 worklist.push(use->in(1));
1127 ctrl_path.push(use);
1128 continue;
1129 }
1130 #ifndef PRODUCT
1131 if (PrintOptimizeStringConcat) {
1132 if (result != last_result) {
1133 last_result = result;
1134 tty->print_cr("extra uses for result:");
1135 last_result->dump();
1136 }
1137 use->dump();
1138 }
1139 #endif
1140 fail = true;
1141 break;
1142 }
1143 }
1144
1145 #ifndef PRODUCT
1146 if (PrintOptimizeStringConcat && !fail) {
1147 ttyLocker ttyl;
1148 tty->cr();
1149 tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size());
1150 _begin->jvms()->dump_spec(tty); tty->cr();
1151 for (int i = 0; i < num_arguments(); i++) {
1152 argument(i)->dump();
1153 }
1154 _control.dump();
1155 tty->cr();
1156 }
1157 #endif
1158
1159 return !fail;
1160 }
1161
1162 // Mirror of Integer.stringSize() method, return the count of digits in integer,
1163 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1164 if (arg->is_Con()) {
1165 // Constant integer. Compute constant length
1166 jint arg_val = arg->get_int();
1167 jint d = 1;
1168 if (arg_val >= 0) {
1169 d = 0;
1170 arg_val = -arg_val;
1171 }
1172 jint p = -10;
1173 for (int i = 1; i < 10; i++) {
1174 if (arg_val > p) {
1175 return __ intcon(i + d);
1176 }
1177 p = java_multiply(10, p);
1178 }
1179 return __ intcon(10 + d);
1180 }
1181
1182 // int d = 1;
1183 // if (x >= 0) {
1184 // d = 0;
1185 // x = -x;
1186 // }
1187 RegionNode* sign_merge = new RegionNode(3);
1188 kit.gvn().set_type(sign_merge, Type::CONTROL);
1189 Node* digit_cnt = new PhiNode(sign_merge, TypeInt::INT);
1190 kit.gvn().set_type(digit_cnt, TypeInt::INT);
1191 Node* val = new PhiNode(sign_merge, TypeInt::INT);
1192 kit.gvn().set_type(val, TypeInt::INT);
1193
1194 IfNode* iff = kit.create_and_map_if(kit.control(),
1195 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::ge),
1196 PROB_FAIR, COUNT_UNKNOWN);
1197 sign_merge->init_req(1, __ IfTrue(iff));
1198 sign_merge->init_req(2, __ IfFalse(iff));
1199 digit_cnt->init_req(1, __ intcon(0));
1200 digit_cnt->init_req(2, __ intcon(1));
1201 val->init_req(1, __ SubI(__ intcon(0), arg));
1202 val->init_req(2, arg);
1203 kit.set_control(sign_merge);
1204
1205 // int p = -10;
1206 // for (int i = 1; i < 10; i++) {
1207 // if (x > p)
1208 // return i + d;
1209 // p = 10 * p;
1210 // }
1211 RegionNode* final_merge = new RegionNode(3);
1212 kit.gvn().set_type(final_merge, Type::CONTROL);
1213 Node* final_size = new PhiNode(final_merge, TypeInt::INT);
1214 kit.gvn().set_type(final_size, TypeInt::INT);
1215
1216 kit.add_parse_predicates();
1217 C->set_has_loops(true);
1218
1219 RegionNode* loop = new RegionNode(3);
1220 kit.gvn().set_type(loop, Type::CONTROL);
1221 Node* index = new PhiNode(loop, TypeInt::INT);
1222 kit.gvn().set_type(index, TypeInt::INT);
1223 Node* temp = new PhiNode(loop, TypeInt::INT);
1224 kit.gvn().set_type(temp, TypeInt::INT);
1225
1226 loop->init_req(1, kit.control());
1227 index->init_req(1, __ intcon(1));
1228 temp->init_req(1, __ intcon(-10));
1229 kit.set_control(loop);
1230
1231 Node* limit = __ CmpI(index, __ intcon(10));
1232 Node* limitb = __ Bool(limit, BoolTest::lt);
1233 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1234 Node* limit_less = __ IfTrue(iff2);
1235 kit.set_control(limit_less);
1236
1237 Node* cmp = __ CmpI(val, temp);
1238 Node* cmpb = __ Bool(cmp, BoolTest::gt);
1239 IfNode* iff3 = kit.create_and_map_if(kit.control(), cmpb, PROB_MIN, COUNT_UNKNOWN);
1240 Node* cmp_le = __ IfFalse(iff3);
1241 kit.set_control(cmp_le);
1242
1243 loop->init_req(2, kit.control());
1244 index->init_req(2, __ AddI(index, __ intcon(1)));
1245 temp->init_req(2, __ MulI(temp, __ intcon(10)));
1246
1247 final_merge->init_req(1, __ IfFalse(iff2));
1248 final_merge->init_req(2, __ IfTrue(iff3));
1249 final_size->init_req(1, __ AddI(digit_cnt, __ intcon(10)));
1250 final_size->init_req(2, __ AddI(digit_cnt, index));
1251 kit.set_control(final_merge);
1252
1253 C->record_for_igvn(sign_merge);
1254 C->record_for_igvn(digit_cnt);
1255 C->record_for_igvn(val);
1256 C->record_for_igvn(final_merge);
1257 C->record_for_igvn(final_size);
1258 C->record_for_igvn(loop);
1259 C->record_for_igvn(index);
1260 C->record_for_igvn(temp);
1261 return final_size;
1262 }
1263
1264 // Simplified version of Integer.getChars
1265 void PhaseStringOpts::getChars(GraphKit& kit, Node* arg, Node* dst_array, BasicType bt, Node* end, Node* final_merge, Node* final_mem, int merge_index) {
1266 // if (i < 0) {
1267 // sign = '-';
1268 // i = -i;
1269 // }
1270 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1271 PROB_FAIR, COUNT_UNKNOWN);
1272
1273 RegionNode* merge = new RegionNode(3);
1274 kit.gvn().set_type(merge, Type::CONTROL);
1275 Node* i = new PhiNode(merge, TypeInt::INT);
1276 kit.gvn().set_type(i, TypeInt::INT);
1277 Node* sign = new PhiNode(merge, TypeInt::INT);
1278 kit.gvn().set_type(sign, TypeInt::INT);
1279
1280 merge->init_req(1, __ IfTrue(iff));
1281 i->init_req(1, __ SubI(__ intcon(0), arg));
1282 sign->init_req(1, __ intcon('-'));
1283 merge->init_req(2, __ IfFalse(iff));
1284 i->init_req(2, arg);
1285 sign->init_req(2, __ intcon(0));
1286
1287 kit.set_control(merge);
1288
1289 C->record_for_igvn(merge);
1290 C->record_for_igvn(i);
1291 C->record_for_igvn(sign);
1292
1293 // for (;;) {
1294 // q = i / 10;
1295 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1296 // buf [--charPos] = digits [r];
1297 // i = q;
1298 // if (i == 0) break;
1299 // }
1300
1301 // Add Parse Predicates first.
1302 kit.add_parse_predicates();
1303
1304 C->set_has_loops(true);
1305 RegionNode* head = new RegionNode(3);
1306 head->init_req(1, kit.control());
1307
1308 kit.gvn().set_type(head, Type::CONTROL);
1309 Node* i_phi = new PhiNode(head, TypeInt::INT);
1310 i_phi->init_req(1, i);
1311 kit.gvn().set_type(i_phi, TypeInt::INT);
1312 Node* charPos = new PhiNode(head, TypeInt::INT);
1313 charPos->init_req(1, end);
1314 kit.gvn().set_type(charPos, TypeInt::INT);
1315 Node* mem = PhiNode::make(head, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1316 kit.gvn().set_type(mem, Type::MEMORY);
1317
1318 kit.set_control(head);
1319 kit.set_memory(mem, byte_adr_idx);
1320
1321 Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));
1322 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1323 __ LShiftI(q, __ intcon(1))));
1324 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1325 Node* ch = __ AddI(r, __ intcon('0'));
1326 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1327 ch, bt, MemNode::unordered, false /* require_atomic_access */,
1328 false /* unaligned */, (bt != T_BYTE) /* mismatched */);
1329
1330 iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1331 PROB_FAIR, COUNT_UNKNOWN);
1332 Node* ne = __ IfTrue(iff);
1333 Node* eq = __ IfFalse(iff);
1334
1335 head->init_req(2, ne);
1336 mem->init_req(2, st);
1337
1338 i_phi->init_req(2, q);
1339 charPos->init_req(2, index);
1340 charPos = index;
1341
1342 kit.set_control(eq);
1343 kit.set_memory(st, byte_adr_idx);
1344
1345 C->record_for_igvn(head);
1346 C->record_for_igvn(mem);
1347 C->record_for_igvn(i_phi);
1348 C->record_for_igvn(charPos);
1349
1350 // if (sign != 0) {
1351 // buf [--charPos] = sign;
1352 // }
1353 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1354 PROB_FAIR, COUNT_UNKNOWN);
1355
1356 final_merge->init_req(merge_index + 2, __ IfFalse(iff));
1357 final_mem->init_req(merge_index + 2, kit.memory(byte_adr_idx));
1358
1359 kit.set_control(__ IfTrue(iff));
1360 if (kit.stopped()) {
1361 final_merge->init_req(merge_index + 1, C->top());
1362 final_mem->init_req(merge_index + 1, C->top());
1363 } else {
1364 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1365 st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1366 sign, bt, MemNode::unordered, false /* require_atomic_access */, false /* unaligned */,
1367 (bt != T_BYTE) /* mismatched */);
1368
1369 final_merge->init_req(merge_index + 1, kit.control());
1370 final_mem->init_req(merge_index + 1, st);
1371 }
1372 }
1373
1374 // Copy the characters representing arg into dst_array starting at start
1375 Node* PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* dst_array, Node* dst_coder, Node* start, Node* size) {
1376 bool dcon = dst_coder->is_Con();
1377 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1378 Node* end = __ AddI(start, __ LShiftI(size, dst_coder));
1379
1380 // The final_merge node has 4 entries in case the encoding is known:
1381 // (0) Control, (1) result w/ sign, (2) result w/o sign, (3) result for Integer.min_value
1382 // or 6 entries in case the encoding is not known:
1383 // (0) Control, (1) Latin1 w/ sign, (2) Latin1 w/o sign, (3) min_value, (4) UTF16 w/ sign, (5) UTF16 w/o sign
1384 RegionNode* final_merge = new RegionNode(dcon ? 4 : 6);
1385 kit.gvn().set_type(final_merge, Type::CONTROL);
1386
1387 Node* final_mem = PhiNode::make(final_merge, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1388 kit.gvn().set_type(final_mem, Type::MEMORY);
1389
1390 // need to handle arg == Integer.MIN_VALUE specially because negating doesn't make it positive
1391 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1392 PROB_FAIR, COUNT_UNKNOWN);
1393
1394 Node* old_mem = kit.memory(byte_adr_idx);
1395
1396 kit.set_control(__ IfFalse(iff));
1397 if (kit.stopped()) {
1398 // Statically not equal to MIN_VALUE so this path is dead
1399 final_merge->init_req(3, kit.control());
1400 } else {
1401 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1402 dst_array, dst_coder, start);
1403 final_merge->init_req(3, kit.control());
1404 final_mem->init_req(3, kit.memory(byte_adr_idx));
1405 }
1406
1407 kit.set_control(__ IfTrue(iff));
1408 kit.set_memory(old_mem, byte_adr_idx);
1409
1410 if (!dcon) {
1411 // Check encoding of destination
1412 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(dst_coder, __ intcon(0)), BoolTest::eq),
1413 PROB_FAIR, COUNT_UNKNOWN);
1414 old_mem = kit.memory(byte_adr_idx);
1415 }
1416 if (!dcon || dbyte) {
1417 // Destination is Latin1,
1418 if (!dcon) {
1419 kit.set_control(__ IfTrue(iff));
1420 }
1421 getChars(kit, arg, dst_array, T_BYTE, end, final_merge, final_mem);
1422 }
1423 if (!dcon || !dbyte) {
1424 // Destination is UTF16
1425 int merge_index = 0;
1426 if (!dcon) {
1427 kit.set_control(__ IfFalse(iff));
1428 kit.set_memory(old_mem, byte_adr_idx);
1429 merge_index = 3; // Account for Latin1 case
1430 }
1431 getChars(kit, arg, dst_array, T_CHAR, end, final_merge, final_mem, merge_index);
1432 }
1433
1434 // Final merge point for Latin1 and UTF16 case
1435 kit.set_control(final_merge);
1436 kit.set_memory(final_mem, byte_adr_idx);
1437
1438 C->record_for_igvn(final_merge);
1439 C->record_for_igvn(final_mem);
1440 return end;
1441 }
1442
1443 // Copy 'count' bytes/chars from src_array to dst_array starting at index start
1444 void PhaseStringOpts::arraycopy(GraphKit& kit, IdealKit& ideal, Node* src_array, Node* dst_array, BasicType elembt, Node* start, Node* count) {
1445 assert(elembt == T_BYTE || elembt == T_CHAR, "Invalid type for arraycopy");
1446
1447 if (elembt == T_CHAR) {
1448 // Get number of chars
1449 count = __ RShiftI(count, __ intcon(1));
1450 }
1451
1452 Node* extra = nullptr;
1453 #ifdef _LP64
1454 count = __ ConvI2L(count);
1455 extra = C->top();
1456 #endif
1457
1458 Node* src_ptr = __ array_element_address(src_array, __ intcon(0), T_BYTE);
1459 Node* dst_ptr = __ array_element_address(dst_array, start, T_BYTE);
1460 // Check if destination address is aligned to HeapWordSize
1461 const TypeInt* tdst = __ gvn().type(start)->is_int();
1462 bool aligned = tdst->is_con() && ((tdst->get_con() * type2aelembytes(T_BYTE)) % HeapWordSize == 0);
1463 // Figure out which arraycopy runtime method to call (disjoint, uninitialized).
1464 const char* copyfunc_name = "arraycopy";
1465 address copyfunc_addr = StubRoutines::select_arraycopy_function(elembt, aligned, true, copyfunc_name, true);
1466 ideal.make_leaf_call_no_fp(OptoRuntime::fast_arraycopy_Type(), copyfunc_addr, copyfunc_name,
1467 TypeAryPtr::BYTES, src_ptr, dst_ptr, count, extra);
1468 }
1469
1470 #undef __
1471 #define __ ideal.
1472
1473 // Copy contents of a Latin1 encoded string from src_array to dst_array
1474 void PhaseStringOpts::copy_latin1_string(GraphKit& kit, IdealKit& ideal, Node* src_array, IdealVariable& count,
1475 Node* dst_array, Node* dst_coder, Node* start) {
1476 bool dcon = dst_coder->is_Con();
1477 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1478
1479 if (!dcon) {
1480 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1481 }
1482 if (!dcon || dbyte) {
1483 // Destination is Latin1. Simply emit a byte arraycopy.
1484 arraycopy(kit, ideal, src_array, dst_array, T_BYTE, start, __ value(count));
1485 }
1486 if (!dcon) {
1487 __ else_();
1488 }
1489 if (!dcon || !dbyte) {
1490 // Destination is UTF16. Inflate src_array into dst_array.
1491 kit.sync_kit(ideal);
1492 if (Matcher::match_rule_supported(Op_StrInflatedCopy)) {
1493 // Use fast intrinsic
1494 Node* src = kit.array_element_address(src_array, kit.intcon(0), T_BYTE);
1495 Node* dst = kit.array_element_address(dst_array, start, T_BYTE);
1496 kit.inflate_string(src, dst, TypeAryPtr::BYTES, __ value(count));
1497 } else {
1498 // No intrinsic available, use slow method
1499 kit.inflate_string_slow(src_array, dst_array, start, __ value(count));
1500 }
1501 ideal.sync_kit(&kit);
1502 // Multiply count by two since we now need two bytes per char
1503 __ set(count, __ LShiftI(__ value(count), __ ConI(1)));
1504 }
1505 if (!dcon) {
1506 __ end_if();
1507 }
1508 }
1509
1510 // Read two bytes from index and index+1 and convert them to a char
1511 static jchar readChar(ciTypeArray* array, int index) {
1512 int shift_high, shift_low;
1513 #ifdef VM_LITTLE_ENDIAN
1514 shift_high = 0;
1515 shift_low = 8;
1516 #else
1517 shift_high = 8;
1518 shift_low = 0;
1519 #endif
1520
1521 jchar b1 = ((jchar) array->byte_at(index)) & 0xff;
1522 jchar b2 = ((jchar) array->byte_at(index+1)) & 0xff;
1523 return (b1 << shift_high) | (b2 << shift_low);
1524 }
1525
1526 // Copy contents of constant src_array to dst_array by emitting individual stores
1527 void PhaseStringOpts::copy_constant_string(GraphKit& kit, IdealKit& ideal, ciTypeArray* src_array, IdealVariable& count,
1528 bool src_is_byte, Node* dst_array, Node* dst_coder, Node* start) {
1529 bool dcon = dst_coder->is_Con();
1530 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1531 int length = src_array->length();
1532
1533 if (!dcon) {
1534 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1535 }
1536 if (!dcon || dbyte) {
1537 // Destination is Latin1. Copy each byte of src_array into dst_array.
1538 Node* index = start;
1539 for (int i = 0; i < length; i++) {
1540 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1541 Node* val = __ ConI(src_array->byte_at(i));
1542 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1543 index = __ AddI(index, __ ConI(1));
1544 }
1545 }
1546 if (!dcon) {
1547 __ else_();
1548 }
1549 if (!dcon || !dbyte) {
1550 // Destination is UTF16. Copy each char of src_array into dst_array.
1551 Node* index = start;
1552 for (int i = 0; i < length; i++) {
1553 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1554 jchar val;
1555 if (src_is_byte) {
1556 val = src_array->byte_at(i) & 0xff;
1557 } else {
1558 val = readChar(src_array, i++);
1559 }
1560 __ store(__ ctrl(), adr, __ ConI(val), T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1561 true /* mismatched */);
1562 index = __ AddI(index, __ ConI(2));
1563 }
1564 if (src_is_byte) {
1565 // Multiply count by two since we now need two bytes per char
1566 __ set(count, __ ConI(2 * length));
1567 }
1568 }
1569 if (!dcon) {
1570 __ end_if();
1571 }
1572 }
1573
1574 // Compress copy contents of the byte/char String str into dst_array starting at index start.
1575 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* dst_array, Node* dst_coder, Node* start) {
1576 Node* src_array = kit.load_String_value(str, true);
1577
1578 IdealKit ideal(&kit, true, true);
1579 IdealVariable count(ideal); __ declarations_done();
1580
1581 if (str->is_Con()) {
1582 // Constant source string
1583 ciTypeArray* src_array_type = get_constant_value(kit, str);
1584
1585 // Check encoding of constant string
1586 bool src_is_byte = (get_constant_coder(kit, str) == java_lang_String::CODER_LATIN1);
1587
1588 // For small constant strings just emit individual stores.
1589 // A length of 6 seems like a good space/speed tradeof.
1590 __ set(count, __ ConI(src_array_type->length()));
1591 int src_len = src_array_type->length() / (src_is_byte ? 1 : 2);
1592 if (src_len < unroll_string_copy_length) {
1593 // Small constant string
1594 copy_constant_string(kit, ideal, src_array_type, count, src_is_byte, dst_array, dst_coder, start);
1595 } else if (src_is_byte) {
1596 // Source is Latin1
1597 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1598 } else {
1599 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1600 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1601 }
1602 } else {
1603 Node* size = kit.load_array_length(src_array);
1604 __ set(count, size);
1605 // Non-constant source string
1606 if (CompactStrings) {
1607 // Emit runtime check for coder
1608 Node* coder = kit.load_String_coder(str, true);
1609 __ if_then(coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1)); {
1610 // Source is Latin1
1611 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1612 } __ else_();
1613 }
1614 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1615 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1616
1617 if (CompactStrings) {
1618 __ end_if();
1619 }
1620 }
1621
1622 // Finally sync IdealKit and GraphKit.
1623 kit.sync_kit(ideal);
1624 return __ AddI(start, __ value(count));
1625 }
1626
1627 // Compress copy the char into dst_array at index start.
1628 Node* PhaseStringOpts::copy_char(GraphKit& kit, Node* val, Node* dst_array, Node* dst_coder, Node* start) {
1629 bool dcon = (dst_coder != nullptr) && dst_coder->is_Con();
1630 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1631
1632 IdealKit ideal(&kit, true, true);
1633 IdealVariable end(ideal); __ declarations_done();
1634 Node* adr = kit.array_element_address(dst_array, start, T_BYTE);
1635 if (!dcon){
1636 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1637 }
1638 if (!dcon || dbyte) {
1639 // Destination is Latin1. Store a byte.
1640 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1641 __ set(end, __ AddI(start, __ ConI(1)));
1642 }
1643 if (!dcon) {
1644 __ else_();
1645 }
1646 if (!dcon || !dbyte) {
1647 // Destination is UTF16. Store a char.
1648 __ store(__ ctrl(), adr, val, T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1649 true /* mismatched */);
1650 __ set(end, __ AddI(start, __ ConI(2)));
1651 }
1652 if (!dcon) {
1653 __ end_if();
1654 }
1655 // Finally sync IdealKit and GraphKit.
1656 kit.sync_kit(ideal);
1657 return __ value(end);
1658 }
1659
1660 #undef __
1661 #define __ kit.
1662
1663 // Allocate a byte array of specified length.
1664 Node* PhaseStringOpts::allocate_byte_array(GraphKit& kit, IdealKit* ideal, Node* length) {
1665 if (ideal != nullptr) {
1666 // Sync IdealKit and graphKit.
1667 kit.sync_kit(*ideal);
1668 }
1669 Node* byte_array = nullptr;
1670 {
1671 PreserveReexecuteState preexecs(&kit);
1672 // The original jvms is for an allocation of either a String or
1673 // StringBuffer so no stack adjustment is necessary for proper
1674 // reexecution. If we deoptimize in the slow path the bytecode
1675 // will be reexecuted and the char[] allocation will be thrown away.
1676 kit.jvms()->set_should_reexecute(true);
1677 byte_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_BYTE))),
1678 length, 1);
1679 }
1680
1681 // Mark the allocation so that zeroing is skipped since the code
1682 // below will overwrite the entire array
1683 AllocateArrayNode* byte_alloc = AllocateArrayNode::Ideal_array_allocation(byte_array);
1684 byte_alloc->maybe_set_complete(_gvn);
1685
1686 if (ideal != nullptr) {
1687 // Sync IdealKit and graphKit.
1688 ideal->sync_kit(&kit);
1689 }
1690 return byte_array;
1691 }
1692
1693 jbyte PhaseStringOpts::get_constant_coder(GraphKit& kit, Node* str) {
1694 assert(str->is_Con(), "String must be constant");
1695 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1696 ciInstance* str_instance = str_type->const_oop()->as_instance();
1697 jbyte coder = str_instance->field_value_by_offset(java_lang_String::coder_offset()).as_byte();
1698 assert(CompactStrings || (coder == java_lang_String::CODER_UTF16), "Strings must be UTF16 encoded");
1699 return coder;
1700 }
1701
1702 int PhaseStringOpts::get_constant_length(GraphKit& kit, Node* str) {
1703 assert(str->is_Con(), "String must be constant");
1704 return get_constant_value(kit, str)->length();
1705 }
1706
1707 ciTypeArray* PhaseStringOpts::get_constant_value(GraphKit& kit, Node* str) {
1708 assert(str->is_Con(), "String must be constant");
1709 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1710 ciInstance* str_instance = str_type->const_oop()->as_instance();
1711 ciObject* src_array = str_instance->field_value_by_offset(java_lang_String::value_offset()).as_object();
1712 return src_array->as_type_array();
1713 }
1714
1715 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1716 // Log a little info about the transformation
1717 sc->maybe_log_transform();
1718
1719 // pull the JVMState of the allocation into a SafePointNode to serve as
1720 // as a shim for the insertion of the new code.
1721 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1722 uint size = sc->begin()->req();
1723 SafePointNode* map = new SafePointNode(size, jvms);
1724
1725 // copy the control and memory state from the final call into our
1726 // new starting state. This allows any preceding tests to feed
1727 // into the new section of code.
1728 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1729 map->init_req(i1, sc->end()->in(i1));
1730 }
1731 // blow away old allocation arguments
1732 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1733 map->init_req(i1, C->top());
1734 }
1735 // Copy the rest of the inputs for the JVMState
1736 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1737 map->init_req(i1, sc->begin()->in(i1));
1738 }
1739 // Make sure the memory state is a MergeMem for parsing.
1740 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1741 map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory)));
1742 }
1743
1744 jvms->set_map(map);
1745 map->ensure_stack(jvms, jvms->method()->max_stack());
1746
1747 // disconnect all the old StringBuilder calls from the graph
1748 sc->eliminate_unneeded_control();
1749
1750 // At this point all the old work has been completely removed from
1751 // the graph and the saved JVMState exists at the point where the
1752 // final toString call used to be.
1753 GraphKit kit(jvms);
1754
1755 // There may be uncommon traps which are still using the
1756 // intermediate states and these need to be rewritten to point at
1757 // the JVMState at the beginning of the transformation.
1758 sc->convert_uncommon_traps(kit, jvms);
1759
1760 // Now insert the logic to compute the size of the string followed
1761 // by all the logic to construct array and resulting string.
1762
1763 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1764
1765 // Create a region for the overflow checks to merge into.
1766 int args = MAX2(sc->num_arguments(), 1);
1767 RegionNode* overflow = new RegionNode(args);
1768 kit.gvn().set_type(overflow, Type::CONTROL);
1769
1770 // Create a hook node to hold onto the individual sizes since they
1771 // are need for the copying phase.
1772 Node* string_sizes = new Node(args);
1773
1774 Node* coder = __ intcon(0);
1775 Node* length = __ intcon(0);
1776 // If at least one argument is UTF16 encoded, we can fix the encoding.
1777 bool coder_fixed = false;
1778
1779 if (!CompactStrings) {
1780 // Fix encoding of result string to UTF16
1781 coder_fixed = true;
1782 coder = __ intcon(java_lang_String::CODER_UTF16);
1783 }
1784
1785 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1786 Node* arg = sc->argument(argi);
1787 switch (sc->mode(argi)) {
1788 case StringConcat::NegativeIntCheckMode: {
1789 // Initial capacity argument might be negative in which case StringBuilder(int) throws
1790 // a NegativeArraySizeException. Insert a runtime check with an uncommon trap.
1791 const TypeInt* type = kit.gvn().type(arg)->is_int();
1792 assert(type->_hi >= 0 && type->_lo < 0, "no runtime int check needed");
1793 Node* p = __ Bool(__ CmpI(arg, kit.intcon(0)), BoolTest::ge);
1794 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1795 {
1796 // Negative int -> uncommon trap.
1797 PreserveJVMState pjvms(&kit);
1798 kit.set_control(__ IfFalse(iff));
1799 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1800 Deoptimization::Action_maybe_recompile);
1801 }
1802 kit.set_control(__ IfTrue(iff));
1803 break;
1804 }
1805 case StringConcat::IntMode: {
1806 Node* string_size = int_stringSize(kit, arg);
1807
1808 // accumulate total
1809 length = __ AddI(length, string_size);
1810
1811 // Cache this value for the use by int_toString
1812 string_sizes->init_req(argi, string_size);
1813 break;
1814 }
1815 case StringConcat::StringNullCheckMode: {
1816 const Type* type = kit.gvn().type(arg);
1817 assert(type != TypePtr::NULL_PTR, "missing check");
1818 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1819 // Null check with uncommon trap since
1820 // StringBuilder(null) throws exception.
1821 // Use special uncommon trap instead of
1822 // calling normal do_null_check().
1823 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1824 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1825 overflow->add_req(__ IfFalse(iff));
1826 Node* notnull = __ IfTrue(iff);
1827 kit.set_control(notnull); // set control for the cast_not_null
1828 arg = kit.cast_not_null(arg, false);
1829 sc->set_argument(argi, arg);
1830 }
1831 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1832 // Fallthrough to add string length.
1833 }
1834 case StringConcat::StringMode: {
1835 const Type* type = kit.gvn().type(arg);
1836 Node* count = nullptr;
1837 Node* arg_coder = nullptr;
1838 if (type == TypePtr::NULL_PTR) {
1839 // replace the argument with the null checked version
1840 arg = null_string;
1841 sc->set_argument(argi, arg);
1842 count = kit.load_String_length(arg, true);
1843 arg_coder = kit.load_String_coder(arg, true);
1844 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1845 // s = s != null ? s : "null";
1846 // length = length + (s.count - s.offset);
1847 RegionNode *r = new RegionNode(3);
1848 kit.gvn().set_type(r, Type::CONTROL);
1849 Node *phi = new PhiNode(r, type);
1850 kit.gvn().set_type(phi, phi->bottom_type());
1851 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1852 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1853 Node* notnull = __ IfTrue(iff);
1854 Node* isnull = __ IfFalse(iff);
1855 kit.set_control(notnull); // set control for the cast_not_null
1856 r->init_req(1, notnull);
1857 phi->init_req(1, kit.cast_not_null(arg, false));
1858 r->init_req(2, isnull);
1859 phi->init_req(2, null_string);
1860 kit.set_control(r);
1861 C->record_for_igvn(r);
1862 C->record_for_igvn(phi);
1863 // replace the argument with the null checked version
1864 arg = phi;
1865 sc->set_argument(argi, arg);
1866 count = kit.load_String_length(arg, true);
1867 arg_coder = kit.load_String_coder(arg, true);
1868 } else {
1869 // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP
1870 // kit.control might be a different test, that can be hoisted above the actual nullcheck
1871 // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck.
1872 count = kit.load_String_length(arg, false);
1873 arg_coder = kit.load_String_coder(arg, false);
1874 }
1875 if (arg->is_Con()) {
1876 // Constant string. Get constant coder and length.
1877 jbyte const_coder = get_constant_coder(kit, arg);
1878 int const_length = get_constant_length(kit, arg);
1879 if (const_coder == java_lang_String::CODER_LATIN1) {
1880 // Can be latin1 encoded
1881 arg_coder = __ intcon(const_coder);
1882 count = __ intcon(const_length);
1883 } else {
1884 // Found UTF16 encoded string. Fix result array encoding to UTF16.
1885 coder_fixed = true;
1886 coder = __ intcon(const_coder);
1887 count = __ intcon(const_length / 2);
1888 }
1889 }
1890
1891 if (!coder_fixed) {
1892 coder = __ OrI(coder, arg_coder);
1893 }
1894 length = __ AddI(length, count);
1895 string_sizes->init_req(argi, nullptr);
1896 break;
1897 }
1898 case StringConcat::CharMode: {
1899 // one character only
1900 const TypeInt* t = kit.gvn().type(arg)->is_int();
1901 if (!coder_fixed && t->is_con()) {
1902 // Constant char
1903 if (t->get_con() <= 255) {
1904 // Can be latin1 encoded
1905 coder = __ OrI(coder, __ intcon(java_lang_String::CODER_LATIN1));
1906 } else {
1907 // Must be UTF16 encoded. Fix result array encoding to UTF16.
1908 coder_fixed = true;
1909 coder = __ intcon(java_lang_String::CODER_UTF16);
1910 }
1911 } else if (!coder_fixed) {
1912 // Not constant
1913 #undef __
1914 #define __ ideal.
1915 IdealKit ideal(&kit, true, true);
1916 IdealVariable char_coder(ideal); __ declarations_done();
1917 // Check if character can be latin1 encoded
1918 __ if_then(arg, BoolTest::le, __ ConI(0xFF));
1919 __ set(char_coder, __ ConI(java_lang_String::CODER_LATIN1));
1920 __ else_();
1921 __ set(char_coder, __ ConI(java_lang_String::CODER_UTF16));
1922 __ end_if();
1923 kit.sync_kit(ideal);
1924 coder = __ OrI(coder, __ value(char_coder));
1925 #undef __
1926 #define __ kit.
1927 }
1928 length = __ AddI(length, __ intcon(1));
1929 break;
1930 }
1931 default:
1932 ShouldNotReachHere();
1933 }
1934 if (argi > 0) {
1935 // Check that the sum hasn't overflowed
1936 IfNode* iff = kit.create_and_map_if(kit.control(),
1937 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1938 PROB_MIN, COUNT_UNKNOWN);
1939 kit.set_control(__ IfFalse(iff));
1940 overflow->set_req(argi, __ IfTrue(iff));
1941 }
1942 }
1943
1944 {
1945 // Hook
1946 PreserveJVMState pjvms(&kit);
1947 kit.set_control(overflow);
1948 C->record_for_igvn(overflow);
1949 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1950 Deoptimization::Action_make_not_entrant);
1951 }
1952
1953 Node* result;
1954 if (!kit.stopped()) {
1955 assert(CompactStrings || (coder->is_Con() && coder->get_int() == java_lang_String::CODER_UTF16),
1956 "Result string must be UTF16 encoded if CompactStrings is disabled");
1957
1958 Node* dst_array = nullptr;
1959 if (sc->num_arguments() == 1 &&
1960 (sc->mode(0) == StringConcat::StringMode ||
1961 sc->mode(0) == StringConcat::StringNullCheckMode)) {
1962 // Handle the case when there is only a single String argument.
1963 // In this case, we can just pull the value from the String itself.
1964 dst_array = kit.load_String_value(sc->argument(0), true);
1965 } else {
1966 // Allocate destination byte array according to coder
1967 dst_array = allocate_byte_array(kit, nullptr, __ LShiftI(length, coder));
1968
1969 // Now copy the string representations into the final byte[]
1970 Node* start = __ intcon(0);
1971 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1972 Node* arg = sc->argument(argi);
1973 switch (sc->mode(argi)) {
1974 case StringConcat::NegativeIntCheckMode:
1975 break; // Nothing to do, was only needed to add a runtime check earlier.
1976 case StringConcat::IntMode: {
1977 start = int_getChars(kit, arg, dst_array, coder, start, string_sizes->in(argi));
1978 break;
1979 }
1980 case StringConcat::StringNullCheckMode:
1981 case StringConcat::StringMode: {
1982 start = copy_string(kit, arg, dst_array, coder, start);
1983 break;
1984 }
1985 case StringConcat::CharMode: {
1986 start = copy_char(kit, arg, dst_array, coder, start);
1987 break;
1988 }
1989 default:
1990 ShouldNotReachHere();
1991 }
1992 }
1993 }
1994
1995 {
1996 PreserveReexecuteState preexecs(&kit);
1997 // The original jvms is for an allocation of either a String or
1998 // StringBuffer so no stack adjustment is necessary for proper
1999 // reexecution.
2000 kit.jvms()->set_should_reexecute(true);
2001 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
2002 }
2003
2004 // Initialize the string
2005 kit.store_String_value(result, dst_array);
2006 kit.store_String_coder(result, coder);
2007
2008 // The value field is final. Emit a barrier here to ensure that the effect
2009 // of the initialization is committed to memory before any code publishes
2010 // a reference to the newly constructed object (see Parse::do_exits()).
2011 assert(AllocateNode::Ideal_allocation(result) != nullptr, "should be newly allocated");
2012 kit.insert_mem_bar(UseStoreStoreForCtor ? Op_MemBarStoreStore : Op_MemBarRelease, result);
2013 } else {
2014 result = C->top();
2015 }
2016 // hook up the outgoing control and result
2017 kit.replace_call(sc->end(), result);
2018
2019 // Unhook any hook nodes
2020 string_sizes->disconnect_inputs(C);
2021 sc->cleanup();
2022 #ifndef PRODUCT
2023 Atomic::inc(&_stropts_replaced);
2024 #endif
2025 }
2026
2027 #ifndef PRODUCT
2028 uint PhaseStringOpts::_stropts_replaced = 0;
2029 uint PhaseStringOpts::_stropts_merged = 0;
2030 uint PhaseStringOpts::_stropts_total = 0;
2031
2032 void PhaseStringOpts::print_statistics() {
2033 tty->print_cr("StringConcat: %4d/%4d/%4d(replaced/merged/total)", _stropts_replaced, _stropts_merged, _stropts_total);
2034 }
2035 #endif