1 /*
2 * Copyright (c) 2009, 2020, 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 "ci/ciSymbols.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "compiler/compileLog.hpp"
29 #include "opto/addnode.hpp"
30 #include "opto/callGenerator.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/divnode.hpp"
33 #include "opto/graphKit.hpp"
34 #include "opto/idealKit.hpp"
35 #include "opto/rootnode.hpp"
36 #include "opto/runtime.hpp"
37 #include "opto/stringopts.hpp"
38 #include "opto/subnode.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "runtime/stubRoutines.hpp"
41
42 #define __ kit.
43
44 class StringConcat : public ResourceObj {
45 private:
46 PhaseStringOpts* _stringopts;
47 Node* _string_alloc;
48 AllocateNode* _begin; // The allocation the begins the pattern
49 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
50 // SB.toString or or String.<init>(SB.toString)
51 bool _multiple; // indicates this is a fusion of two or more
52 // separate StringBuilders
53
54 Node* _arguments; // The list of arguments to be concatenated
55 GrowableArray<int> _mode; // into a String along with a mode flag
56 // indicating how to treat the value.
57 Node_List _constructors; // List of constructors (many in case of stacked concat)
58 Node_List _control; // List of control nodes that will be deleted
59 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
60 // to restart at the initial JVMState.
61
62 public:
63 // Mode for converting arguments to Strings
64 enum {
65 StringMode,
66 IntMode,
67 CharMode,
68 StringNullCheckMode,
69 NegativeIntCheckMode
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
127 void push_string_null_check(Node* value) {
128 push(value, StringNullCheckMode);
129 }
130
131 void push_negative_int_check(Node* value) {
132 push(value, NegativeIntCheckMode);
133 }
134
135 void push_int(Node* value) {
136 push(value, IntMode);
137 }
138
139 void push_char(Node* value) {
140 push(value, CharMode);
141 }
142
143 static bool is_SB_toString(Node* call) {
144 if (call->is_CallStaticJava()) {
145 CallStaticJavaNode* csj = call->as_CallStaticJava();
146 ciMethod* m = csj->method();
147 if (m != NULL &&
148 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
149 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
150 return true;
151 }
152 }
153 return false;
154 }
155
156 static Node* skip_string_null_check(Node* value) {
157 // Look for a diamond shaped Null check of toString() result
158 // (could be code from String.valueOf()):
159 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
160 if (value->is_Phi()) {
161 int true_path = value->as_Phi()->is_diamond_phi();
162 if (true_path != 0) {
163 // phi->region->if_proj->ifnode->bool
164 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
165 Node* cmp = b->in(1);
166 Node* v1 = cmp->in(1);
167 Node* v2 = cmp->in(2);
168 // Null check of the return of toString which can simply be skipped.
169 if (b->_test._test == BoolTest::ne &&
170 v2->bottom_type() == TypePtr::NULL_PTR &&
171 value->in(true_path)->Opcode() == Op_CastPP &&
172 value->in(true_path)->in(1) == v1 &&
173 v1->is_Proj() && is_SB_toString(v1->in(0))) {
174 return v1;
175 }
176 }
177 }
178 return value;
179 }
180
181 Node* argument(int i) {
182 return _arguments->in(i);
183 }
184 Node* argument_uncast(int i) {
185 Node* arg = argument(i);
186 int amode = mode(i);
187 if (amode == StringConcat::StringMode ||
188 amode == StringConcat::StringNullCheckMode) {
189 arg = skip_string_null_check(arg);
190 }
191 return arg;
192 }
193 void set_argument(int i, Node* value) {
194 _arguments->set_req(i, value);
195 }
196 int num_arguments() {
197 return _mode.length();
198 }
199 int mode(int i) {
200 return _mode.at(i);
201 }
202 void add_control(Node* ctrl) {
203 assert(!_control.contains(ctrl), "only push once");
204 _control.push(ctrl);
205 }
206 void add_constructor(Node* init) {
207 assert(!_constructors.contains(init), "only push once");
208 _constructors.push(init);
209 }
210 CallStaticJavaNode* end() { return _end; }
211 AllocateNode* begin() { return _begin; }
212 Node* string_alloc() { return _string_alloc; }
213
214 void eliminate_unneeded_control();
215 void eliminate_initialize(InitializeNode* init);
216 void eliminate_call(CallNode* call);
217
218 void maybe_log_transform() {
219 CompileLog* log = _stringopts->C->log();
220 if (log != NULL) {
221 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
222 num_arguments(),
223 _string_alloc != NULL,
224 _multiple);
225 JVMState* p = _begin->jvms();
226 while (p != NULL) {
227 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
228 p = p->caller();
229 }
230 log->tail("replace_string_concat");
231 }
232 }
233
234 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
235 for (uint u = 0; u < _uncommon_traps.size(); u++) {
236 Node* uct = _uncommon_traps.at(u);
237
238 // Build a new call using the jvms state of the allocate
239 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
240 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
241 const TypePtr* no_memory_effects = NULL;
242 Compile* C = _stringopts->C;
243 CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
244 no_memory_effects);
245 for (int e = 0; e < TypeFunc::Parms; e++) {
246 call->init_req(e, uct->in(e));
247 }
248 // Set the trap request to record intrinsic failure if this trap
249 // is taken too many times. Ideally we would handle then traps by
250 // doing the original bookkeeping in the MDO so that if it caused
251 // the code to be thrown out we could still recompile and use the
252 // optimization. Failing the uncommon traps doesn't really mean
253 // that the optimization is a bad idea but there's no other way to
254 // do the MDO updates currently.
255 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
256 Deoptimization::Action_make_not_entrant);
257 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
258 kit.add_safepoint_edges(call);
259
260 _stringopts->gvn()->transform(call);
261 C->gvn_replace_by(uct, call);
262 uct->disconnect_inputs(C);
263 }
264 }
265
266 void cleanup() {
267 // disconnect the hook node
268 _arguments->disconnect_inputs(_stringopts->C);
269 }
270 };
271
272
273 void StringConcat::eliminate_unneeded_control() {
274 for (uint i = 0; i < _control.size(); i++) {
275 Node* n = _control.at(i);
276 if (n->is_Allocate()) {
277 eliminate_initialize(n->as_Allocate()->initialization());
278 }
279 if (n->is_Call()) {
280 if (n != _end) {
281 eliminate_call(n->as_Call());
282 }
283 } else if (n->is_IfTrue()) {
284 Compile* C = _stringopts->C;
285 C->gvn_replace_by(n, n->in(0)->in(0));
286 // get rid of the other projection
287 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
288 } else if (n->is_Region()) {
289 Node* iff = n->in(1)->in(0);
290 assert(n->req() == 3 && n->in(2)->in(0) == iff, "not a diamond");
291 assert(iff->is_If(), "no if for the diamond");
292 Node* bol = iff->in(1);
293 assert(bol->is_Bool(), "unexpected if shape");
294 Node* cmp = bol->in(1);
295 assert(cmp->is_Cmp(), "unexpected if shape");
296 if (cmp->in(1)->is_top() || cmp->in(2)->is_top()) {
297 // This region should lose its Phis and be optimized out by igvn but there's a chance the if folds to top first
298 // which then causes a reachable part of the graph to become dead.
299 Compile* C = _stringopts->C;
300 C->gvn_replace_by(n, iff->in(0));
301 }
302 }
303 }
304 }
305
306
307 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
308 StringConcat* result = new StringConcat(_stringopts, _end);
309 for (uint x = 0; x < _control.size(); x++) {
310 Node* n = _control.at(x);
311 if (n->is_Call()) {
312 result->_control.push(n);
313 }
314 }
315 for (uint x = 0; x < other->_control.size(); x++) {
316 Node* n = other->_control.at(x);
317 if (n->is_Call()) {
318 result->_control.push(n);
319 }
320 }
321 assert(result->_control.contains(other->_end), "what?");
322 assert(result->_control.contains(_begin), "what?");
323 for (int x = 0; x < num_arguments(); x++) {
324 Node* argx = argument_uncast(x);
325 if (argx == arg) {
326 // replace the toString result with the all the arguments that
327 // made up the other StringConcat
328 for (int y = 0; y < other->num_arguments(); y++) {
329 result->append(other->argument(y), other->mode(y));
330 }
331 } else {
332 result->append(argx, mode(x));
333 }
334 }
335 result->set_allocation(other->_begin);
336 for (uint i = 0; i < _constructors.size(); i++) {
337 result->add_constructor(_constructors.at(i));
338 }
339 for (uint i = 0; i < other->_constructors.size(); i++) {
340 result->add_constructor(other->_constructors.at(i));
341 }
342 result->_multiple = true;
343 return result;
344 }
345
346
347 void StringConcat::eliminate_call(CallNode* call) {
348 Compile* C = _stringopts->C;
349 CallProjections projs;
350 call->extract_projections(&projs, false);
351 if (projs.fallthrough_catchproj != NULL) {
352 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
353 }
354 if (projs.fallthrough_memproj != NULL) {
355 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
356 }
357 if (projs.catchall_memproj != NULL) {
358 C->gvn_replace_by(projs.catchall_memproj, C->top());
359 }
360 if (projs.fallthrough_ioproj != NULL) {
361 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
362 }
363 if (projs.catchall_ioproj != NULL) {
364 C->gvn_replace_by(projs.catchall_ioproj, C->top());
365 }
366 if (projs.catchall_catchproj != NULL) {
367 // EA can't cope with the partially collapsed graph this
368 // creates so put it on the worklist to be collapsed later.
369 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
370 Node *use = i.get();
371 int opc = use->Opcode();
372 if (opc == Op_CreateEx || opc == Op_Region) {
373 _stringopts->record_dead_node(use);
374 }
375 }
376 C->gvn_replace_by(projs.catchall_catchproj, C->top());
377 }
378 if (projs.resproj != NULL) {
379 C->gvn_replace_by(projs.resproj, C->top());
380 }
381 C->gvn_replace_by(call, C->top());
382 }
383
384 void StringConcat::eliminate_initialize(InitializeNode* init) {
385 Compile* C = _stringopts->C;
386
387 // Eliminate Initialize node.
388 assert(init->outcnt() <= 2, "only a control and memory projection expected");
389 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
390 Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
391 if (ctrl_proj != NULL) {
392 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
393 }
394 Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
395 if (mem_proj != NULL) {
396 Node *mem = init->in(TypeFunc::Memory);
397 C->gvn_replace_by(mem_proj, mem);
398 }
399 C->gvn_replace_by(init, C->top());
400 init->disconnect_inputs(C);
401 }
402
403 Node_List PhaseStringOpts::collect_toString_calls() {
404 Node_List string_calls;
405 Node_List worklist;
406
407 _visited.clear();
408
409 // Prime the worklist
410 for (uint i = 1; i < C->root()->len(); i++) {
411 Node* n = C->root()->in(i);
412 if (n != NULL && !_visited.test_set(n->_idx)) {
413 worklist.push(n);
414 }
415 }
416
417 while (worklist.size() > 0) {
418 Node* ctrl = worklist.pop();
419 if (StringConcat::is_SB_toString(ctrl)) {
420 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
421 string_calls.push(csj);
422 }
423 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
424 worklist.push(ctrl->in(0));
425 }
426 if (ctrl->is_Region()) {
427 for (uint i = 1; i < ctrl->len(); i++) {
428 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
429 worklist.push(ctrl->in(i));
430 }
431 }
432 }
433 }
434 return string_calls;
435 }
436
437
438 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
439 ciMethod* m = call->method();
440 ciSymbol* string_sig;
441 ciSymbol* int_sig;
442 ciSymbol* char_sig;
443 if (m->holder() == C->env()->StringBuilder_klass()) {
444 string_sig = ciSymbols::String_StringBuilder_signature();
445 int_sig = ciSymbols::int_StringBuilder_signature();
446 char_sig = ciSymbols::char_StringBuilder_signature();
447 } else if (m->holder() == C->env()->StringBuffer_klass()) {
448 string_sig = ciSymbols::String_StringBuffer_signature();
449 int_sig = ciSymbols::int_StringBuffer_signature();
450 char_sig = ciSymbols::char_StringBuffer_signature();
451 } else {
452 return NULL;
453 }
454 #ifndef PRODUCT
455 if (PrintOptimizeStringConcat) {
456 tty->print("considering toString call in ");
457 call->jvms()->dump_spec(tty); tty->cr();
458 }
459 #endif
460
461 StringConcat* sc = new StringConcat(this, call);
462
463 AllocateNode* alloc = NULL;
464 InitializeNode* init = NULL;
465
466 // possible opportunity for StringBuilder fusion
467 CallStaticJavaNode* cnode = call;
468 while (cnode) {
469 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
470 if (recv->is_Proj()) {
471 recv = recv->in(0);
472 }
473 cnode = recv->isa_CallStaticJava();
474 if (cnode == NULL) {
475 alloc = recv->isa_Allocate();
476 if (alloc == NULL) {
477 break;
478 }
479 // Find the constructor call
480 Node* result = alloc->result_cast();
481 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
482 // strange looking allocation
483 #ifndef PRODUCT
484 if (PrintOptimizeStringConcat) {
485 tty->print("giving up because allocation looks strange ");
486 alloc->jvms()->dump_spec(tty); tty->cr();
487 }
488 #endif
489 break;
490 }
491 Node* constructor = NULL;
492 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
493 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
494 if (use != NULL &&
495 use->method() != NULL &&
496 !use->method()->is_static() &&
497 use->method()->name() == ciSymbols::object_initializer_name() &&
498 use->method()->holder() == m->holder()) {
499 // Matched the constructor.
500 ciSymbol* sig = use->method()->signature()->as_symbol();
501 if (sig == ciSymbols::void_method_signature() ||
502 sig == ciSymbols::int_void_signature() ||
503 sig == ciSymbols::string_void_signature()) {
504 if (sig == ciSymbols::string_void_signature()) {
505 // StringBuilder(String) so pick this up as the first argument
506 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
507 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
508 if (type == TypePtr::NULL_PTR) {
509 // StringBuilder(null) throws exception.
510 #ifndef PRODUCT
511 if (PrintOptimizeStringConcat) {
512 tty->print("giving up because StringBuilder(null) throws exception");
513 alloc->jvms()->dump_spec(tty);
514 tty->cr();
515 }
516 #endif
517 return NULL;
518 }
519 // StringBuilder(str) argument needs null check.
520 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
521 } else if (sig == ciSymbols::int_void_signature()) {
522 // StringBuilder(int) case.
523 Node* parm = use->in(TypeFunc::Parms + 1);
524 assert(parm != NULL, "must exist");
525 const TypeInt* type = _gvn->type(parm)->is_int();
526 if (type->_hi < 0) {
527 // Initial capacity argument is always negative in which case StringBuilder(int) throws
528 // a NegativeArraySizeException. Bail out from string opts.
529 #ifndef PRODUCT
530 if (PrintOptimizeStringConcat) {
531 tty->print("giving up because a negative argument is passed to StringBuilder(int) which "
532 "throws a NegativeArraySizeException");
533 alloc->jvms()->dump_spec(tty);
534 tty->cr();
535 }
536 #endif
537 return NULL;
538 } else if (type->_lo < 0) {
539 // Argument could be negative: We need a runtime check to throw NegativeArraySizeException in that case.
540 sc->push_negative_int_check(parm);
541 }
542 }
543 // The int variant takes an initial size for the backing
544 // array so just treat it like the void version.
545 constructor = use;
546 } else {
547 #ifndef PRODUCT
548 if (PrintOptimizeStringConcat) {
549 tty->print("unexpected constructor signature: %s", sig->as_utf8());
550 }
551 #endif
552 }
553 break;
554 }
555 }
556 if (constructor == NULL) {
557 // couldn't find constructor
558 #ifndef PRODUCT
559 if (PrintOptimizeStringConcat) {
560 tty->print("giving up because couldn't find constructor ");
561 alloc->jvms()->dump_spec(tty); tty->cr();
562 }
563 #endif
564 break;
565 }
566
567 // Walked all the way back and found the constructor call so see
568 // if this call converted into a direct string concatenation.
569 sc->add_control(call);
570 sc->add_control(constructor);
571 sc->add_control(alloc);
572 sc->set_allocation(alloc);
573 sc->add_constructor(constructor);
574 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
575 return sc;
576 } else {
577 return NULL;
578 }
579 } else if (cnode->method() == NULL) {
580 break;
581 } else if (!cnode->method()->is_static() &&
582 cnode->method()->holder() == m->holder() &&
583 cnode->method()->name() == ciSymbols::append_name() &&
584 (cnode->method()->signature()->as_symbol() == string_sig ||
585 cnode->method()->signature()->as_symbol() == char_sig ||
586 cnode->method()->signature()->as_symbol() == int_sig)) {
587 sc->add_control(cnode);
588 Node* arg = cnode->in(TypeFunc::Parms + 1);
589 if (arg == NULL || arg->is_top()) {
590 #ifndef PRODUCT
591 if (PrintOptimizeStringConcat) {
592 tty->print("giving up because the call is effectively dead");
593 cnode->jvms()->dump_spec(tty); tty->cr();
594 }
595 #endif
596 break;
597 }
598 if (cnode->method()->signature()->as_symbol() == int_sig) {
599 sc->push_int(arg);
600 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
601 sc->push_char(arg);
602 } else {
603 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
604 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
605 if (csj->method() != NULL &&
606 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
607 arg->outcnt() == 1) {
608 // _control is the list of StringBuilder calls nodes which
609 // will be replaced by new String code after this optimization.
610 // Integer::toString() call is not part of StringBuilder calls
611 // chain. It could be eliminated only if its result is used
612 // only by this SB calls chain.
613 // Another limitation: it should be used only once because
614 // it is unknown that it is used only by this SB calls chain
615 // until all related SB calls nodes are collected.
616 assert(arg->unique_out() == cnode, "sanity");
617 sc->add_control(csj);
618 sc->push_int(csj->in(TypeFunc::Parms));
619 continue;
620 }
621 }
622 sc->push_string(arg);
623 }
624 continue;
625 } else {
626 // some unhandled signature
627 #ifndef PRODUCT
628 if (PrintOptimizeStringConcat) {
629 tty->print("giving up because encountered unexpected signature ");
630 cnode->tf()->dump(); tty->cr();
631 cnode->in(TypeFunc::Parms + 1)->dump();
632 }
633 #endif
634 break;
635 }
636 }
637 return NULL;
638 }
639
640
641 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
642 Phase(StringOpts),
643 _gvn(gvn) {
644
645 assert(OptimizeStringConcat, "shouldn't be here");
646
647 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
648 ciSymbols::int_array_signature(), true);
649 if (size_table_field == NULL) {
650 // Something wrong so give up.
651 assert(false, "why can't we find Integer.sizeTable?");
652 return;
653 }
654
655 // Collect the types needed to talk about the various slices of memory
656 byte_adr_idx = C->get_alias_index(TypeAryPtr::BYTES);
657
658 // For each locally allocated StringBuffer see if the usages can be
659 // collapsed into a single String construction.
660
661 // Run through the list of allocation looking for SB.toString to see
662 // if it's possible to fuse the usage of the SB into a single String
663 // construction.
664 GrowableArray<StringConcat*> concats;
665 Node_List toStrings = collect_toString_calls();
666 while (toStrings.size() > 0) {
667 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
668 if (sc != NULL) {
669 concats.push(sc);
670 }
671 }
672
673 // try to coalesce separate concats
674 restart:
675 for (int c = 0; c < concats.length(); c++) {
676 StringConcat* sc = concats.at(c);
677 for (int i = 0; i < sc->num_arguments(); i++) {
678 Node* arg = sc->argument_uncast(i);
679 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
680 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
681 for (int o = 0; o < concats.length(); o++) {
682 if (c == o) continue;
683 StringConcat* other = concats.at(o);
684 if (other->end() == csj) {
685 #ifndef PRODUCT
686 if (PrintOptimizeStringConcat) {
687 tty->print_cr("considering stacked concats");
688 }
689 #endif
690
691 StringConcat* merged = sc->merge(other, arg);
692 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
693 #ifndef PRODUCT
694 if (PrintOptimizeStringConcat) {
695 tty->print_cr("stacking would succeed");
696 }
697 #endif
698 if (c < o) {
699 concats.remove_at(o);
700 concats.at_put(c, merged);
701 } else {
702 concats.remove_at(c);
703 concats.at_put(o, merged);
704 }
705 goto restart;
706 } else {
707 #ifndef PRODUCT
708 if (PrintOptimizeStringConcat) {
709 tty->print_cr("stacking would fail");
710 }
711 #endif
712 }
713 }
714 }
715 }
716 }
717 }
718
719
720 for (int c = 0; c < concats.length(); c++) {
721 StringConcat* sc = concats.at(c);
722 replace_string_concat(sc);
723 }
724
725 remove_dead_nodes();
726 }
727
728 void PhaseStringOpts::record_dead_node(Node* dead) {
729 dead_worklist.push(dead);
730 }
731
732 void PhaseStringOpts::remove_dead_nodes() {
733 // Delete any dead nodes to make things clean enough that escape
734 // analysis doesn't get unhappy.
735 while (dead_worklist.size() > 0) {
736 Node* use = dead_worklist.pop();
737 int opc = use->Opcode();
738 switch (opc) {
739 case Op_Region: {
740 uint i = 1;
741 for (i = 1; i < use->req(); i++) {
742 if (use->in(i) != C->top()) {
743 break;
744 }
745 }
746 if (i >= use->req()) {
747 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
748 Node* m = i.get();
749 if (m->is_Phi()) {
750 dead_worklist.push(m);
751 }
752 }
753 C->gvn_replace_by(use, C->top());
754 }
755 break;
756 }
757 case Op_AddP:
758 case Op_CreateEx: {
759 // Recurisvely clean up references to CreateEx so EA doesn't
760 // get unhappy about the partially collapsed graph.
761 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
762 Node* m = i.get();
763 if (m->is_AddP()) {
764 dead_worklist.push(m);
765 }
766 }
767 C->gvn_replace_by(use, C->top());
768 break;
769 }
770 case Op_Phi:
771 if (use->in(0) == C->top()) {
772 C->gvn_replace_by(use, C->top());
773 }
774 break;
775 }
776 }
777 }
778
779
780 bool StringConcat::validate_mem_flow() {
781 Compile* C = _stringopts->C;
782
783 for (uint i = 0; i < _control.size(); i++) {
784 #ifndef PRODUCT
785 Node_List path;
786 #endif
787 Node* curr = _control.at(i);
788 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
789 // Now here's the main invariant in our case:
790 // For memory between the constructor, and appends, and toString we should only see bottom memory,
791 // produced by the previous call we know about.
792 if (!_constructors.contains(curr)) {
793 NOT_PRODUCT(path.push(curr);)
794 Node* mem = curr->in(TypeFunc::Memory);
795 assert(mem != NULL, "calls should have memory edge");
796 assert(!mem->is_Phi(), "should be handled by control flow validation");
797 NOT_PRODUCT(path.push(mem);)
798 while (mem->is_MergeMem()) {
799 for (uint i = 1; i < mem->req(); i++) {
800 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
801 #ifndef PRODUCT
802 if (PrintOptimizeStringConcat) {
803 tty->print("fusion has incorrect memory flow (side effects) for ");
804 _begin->jvms()->dump_spec(tty); tty->cr();
805 path.dump();
806 }
807 #endif
808 return false;
809 }
810 }
811 // skip through a potential MergeMem chain, linked through Bot
812 mem = mem->in(Compile::AliasIdxBot);
813 NOT_PRODUCT(path.push(mem);)
814 }
815 // now let it fall through, and see if we have a projection
816 if (mem->is_Proj()) {
817 // Should point to a previous known call
818 Node *prev = mem->in(0);
819 NOT_PRODUCT(path.push(prev);)
820 if (!prev->is_Call() || !_control.contains(prev)) {
821 #ifndef PRODUCT
822 if (PrintOptimizeStringConcat) {
823 tty->print("fusion has incorrect memory flow (unknown call) for ");
824 _begin->jvms()->dump_spec(tty); tty->cr();
825 path.dump();
826 }
827 #endif
828 return false;
829 }
830 } else {
831 assert(mem->is_Store() || mem->is_LoadStore(), "unexpected node type: %s", mem->Name());
832 #ifndef PRODUCT
833 if (PrintOptimizeStringConcat) {
834 tty->print("fusion has incorrect memory flow (unexpected source) for ");
835 _begin->jvms()->dump_spec(tty); tty->cr();
836 path.dump();
837 }
838 #endif
839 return false;
840 }
841 } else {
842 // For memory that feeds into constructors it's more complicated.
843 // However the advantage is that any side effect that happens between the Allocate/Initialize and
844 // the constructor will have to be control-dependent on Initialize.
845 // So we actually don't have to do anything, since it's going to be caught by the control flow
846 // analysis.
847 #ifdef ASSERT
848 // Do a quick verification of the control pattern between the constructor and the initialize node
849 assert(curr->is_Call(), "constructor should be a call");
850 // Go up the control starting from the constructor call
851 Node* ctrl = curr->in(0);
852 IfNode* iff = NULL;
853 RegionNode* copy = NULL;
854
855 while (true) {
856 // skip known check patterns
857 if (ctrl->is_Region()) {
858 if (ctrl->as_Region()->is_copy()) {
859 copy = ctrl->as_Region();
860 ctrl = copy->is_copy();
861 } else { // a cast
862 assert(ctrl->req() == 3 &&
863 ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() &&
864 ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() &&
865 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
866 ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(),
867 "must be a simple diamond");
868 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
869 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
870 Node* use = i.get();
871 assert(use == ctrl || use->is_ConstraintCast(),
872 "unexpected user: %s", use->Name());
873 }
874
875 iff = ctrl->in(1)->in(0)->as_If();
876 ctrl = iff->in(0);
877 }
878 } else if (ctrl->is_IfTrue()) { // null checks, class checks
879 iff = ctrl->in(0)->as_If();
880 // Verify that the other arm is an uncommon trap
881 Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
882 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
883 assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommon trap");
884 ctrl = iff->in(0);
885 } else {
886 break;
887 }
888 }
889
890 assert(ctrl->is_Proj(), "must be a projection");
891 assert(ctrl->in(0)->is_Initialize(), "should be initialize");
892 for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) {
893 Node* use = i.get();
894 assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(),
895 "unexpected user: %s", use->Name());
896 }
897 #endif // ASSERT
898 }
899 }
900 }
901
902 #ifndef PRODUCT
903 if (PrintOptimizeStringConcat) {
904 tty->print("fusion has correct memory flow for ");
905 _begin->jvms()->dump_spec(tty); tty->cr();
906 tty->cr();
907 }
908 #endif
909 return true;
910 }
911
912 bool StringConcat::validate_control_flow() {
913 // We found all the calls and arguments now lets see if it's
914 // safe to transform the graph as we would expect.
915
916 // Check to see if this resulted in too many uncommon traps previously
917 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
918 Deoptimization::Reason_intrinsic)) {
919 return false;
920 }
921
922 // Walk backwards over the control flow from toString to the
923 // allocation and make sure all the control flow is ok. This
924 // means it's either going to be eliminated once the calls are
925 // removed or it can safely be transformed into an uncommon
926 // trap.
927
928 int null_check_count = 0;
929 Unique_Node_List ctrl_path;
930
931 assert(_control.contains(_begin), "missing");
932 assert(_control.contains(_end), "missing");
933
934 // Collect the nodes that we know about and will eliminate into ctrl_path
935 for (uint i = 0; i < _control.size(); i++) {
936 // Push the call and it's control projection
937 Node* n = _control.at(i);
938 if (n->is_Allocate()) {
939 AllocateNode* an = n->as_Allocate();
940 InitializeNode* init = an->initialization();
941 ctrl_path.push(init);
942 ctrl_path.push(init->as_Multi()->proj_out(0));
943 }
944 if (n->is_Call()) {
945 CallNode* cn = n->as_Call();
946 ctrl_path.push(cn);
947 ctrl_path.push(cn->proj_out(0));
948 ctrl_path.push(cn->proj_out(0)->unique_out());
949 Node* catchproj = cn->proj_out(0)->unique_out()->as_Catch()->proj_out_or_null(0);
950 if (catchproj != NULL) {
951 ctrl_path.push(catchproj);
952 }
953 } else {
954 ShouldNotReachHere();
955 }
956 }
957
958 // Skip backwards through the control checking for unexpected control flow
959 Node* ptr = _end;
960 bool fail = false;
961 while (ptr != _begin) {
962 if (ptr->is_Call() && ctrl_path.member(ptr)) {
963 ptr = ptr->in(0);
964 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
965 ptr = ptr->in(0)->in(0)->in(0);
966 assert(ctrl_path.member(ptr), "should be a known piece of control");
967 } else if (ptr->is_IfTrue()) {
968 IfNode* iff = ptr->in(0)->as_If();
969 BoolNode* b = iff->in(1)->isa_Bool();
970
971 if (b == NULL) {
972 #ifndef PRODUCT
973 if (PrintOptimizeStringConcat) {
974 tty->print_cr("unexpected input to IfNode");
975 iff->in(1)->dump();
976 tty->cr();
977 }
978 #endif
979 fail = true;
980 break;
981 }
982
983 Node* cmp = b->in(1);
984 Node* v1 = cmp->in(1);
985 Node* v2 = cmp->in(2);
986 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
987
988 // Null check of the return of append which can simply be eliminated
989 if (b->_test._test == BoolTest::ne &&
990 v2->bottom_type() == TypePtr::NULL_PTR &&
991 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
992 // NULL check of the return value of the append
993 null_check_count++;
994 if (otherproj->outcnt() == 1) {
995 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
996 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
997 ctrl_path.push(call);
998 }
999 }
1000 _control.push(ptr);
1001 ptr = ptr->in(0)->in(0);
1002 continue;
1003 }
1004
1005 // A test which leads to an uncommon trap which should be safe.
1006 // Later this trap will be converted into a trap that restarts
1007 // at the beginning.
1008 if (otherproj->outcnt() == 1) {
1009 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
1010 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
1011 // control flow leads to uct so should be ok
1012 _uncommon_traps.push(call);
1013 ctrl_path.push(call);
1014 ptr = ptr->in(0)->in(0);
1015 continue;
1016 }
1017 }
1018
1019 #ifndef PRODUCT
1020 // Some unexpected control flow we don't know how to handle.
1021 if (PrintOptimizeStringConcat) {
1022 tty->print_cr("failing with unknown test");
1023 b->dump();
1024 cmp->dump();
1025 v1->dump();
1026 v2->dump();
1027 tty->cr();
1028 }
1029 #endif
1030 fail = true;
1031 break;
1032 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
1033 ptr = ptr->in(0)->in(0);
1034 } else if (ptr->is_Region()) {
1035 Node* copy = ptr->as_Region()->is_copy();
1036 if (copy != NULL) {
1037 ptr = copy;
1038 continue;
1039 }
1040 if (ptr->req() == 3 &&
1041 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
1042 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
1043 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
1044 ptr->in(1)->in(0) != NULL && 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 != NULL) {
1098 _stringopts->_visited.test_set(cnode->_idx);
1099 }
1100 Node* result = cnode != NULL ? cnode->proj_out_or_null(TypeFunc::Parms) : NULL;
1101 if (result != NULL && result != final_result) {
1102 worklist.push(result);
1103 }
1104 }
1105
1106 Node* last_result = NULL;
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 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
1163 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
1164 Node* klass_node = __ makecon(mirror_type);
1165 BasicType bt = field->layout_type();
1166 ciType* field_klass = field->type();
1167
1168 const Type *type;
1169 if( bt == T_OBJECT ) {
1170 if (!field->type()->is_loaded()) {
1171 type = TypeInstPtr::BOTTOM;
1172 } else if (field->is_static_constant()) {
1173 // This can happen if the constant oop is non-perm.
1174 ciObject* con = field->constant_value().as_object();
1175 // Do not "join" in the previous type; it doesn't add value,
1176 // and may yield a vacuous result if the field is of interface type.
1177 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
1178 assert(type != NULL, "field singleton type must be consistent");
1179 return __ makecon(type);
1180 } else {
1181 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
1182 }
1183 } else {
1184 type = Type::get_const_basic_type(bt);
1185 }
1186
1187 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
1188 type, T_OBJECT,
1189 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())),
1190 MemNode::unordered);
1191 }
1192
1193 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1194 if (arg->is_Con()) {
1195 // Constant integer. Compute constant length using Integer.sizeTable
1196 int arg_val = arg->get_int();
1197 int count = 1;
1198 if (arg_val < 0) {
1199 // Special case for min_jint - it can't be negated.
1200 if (arg_val == min_jint) {
1201 return __ intcon(11);
1202 }
1203
1204 arg_val = -arg_val;
1205 count++;
1206 }
1207
1208 ciArray* size_table = (ciArray*)size_table_field->constant_value().as_object();
1209 for (int i = 0; i < size_table->length(); i++) {
1210 if (arg_val <= size_table->element_value(i).as_int()) {
1211 count += i;
1212 break;
1213 }
1214 }
1215 return __ intcon(count);
1216 }
1217
1218 RegionNode *final_merge = new RegionNode(3);
1219 kit.gvn().set_type(final_merge, Type::CONTROL);
1220 Node* final_size = new PhiNode(final_merge, TypeInt::INT);
1221 kit.gvn().set_type(final_size, TypeInt::INT);
1222
1223 IfNode* iff = kit.create_and_map_if(kit.control(),
1224 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1225 PROB_FAIR, COUNT_UNKNOWN);
1226 Node* is_min = __ IfFalse(iff);
1227 final_merge->init_req(1, is_min);
1228 final_size->init_req(1, __ intcon(11));
1229
1230 kit.set_control(__ IfTrue(iff));
1231 if (kit.stopped()) {
1232 final_merge->init_req(2, C->top());
1233 final_size->init_req(2, C->top());
1234 } else {
1235
1236 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1237 RegionNode *r = new RegionNode(3);
1238 kit.gvn().set_type(r, Type::CONTROL);
1239 Node *phi = new PhiNode(r, TypeInt::INT);
1240 kit.gvn().set_type(phi, TypeInt::INT);
1241 Node *size = new PhiNode(r, TypeInt::INT);
1242 kit.gvn().set_type(size, TypeInt::INT);
1243 Node* chk = __ CmpI(arg, __ intcon(0));
1244 Node* p = __ Bool(chk, BoolTest::lt);
1245 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1246 Node* lessthan = __ IfTrue(iff);
1247 Node* greaterequal = __ IfFalse(iff);
1248 r->init_req(1, lessthan);
1249 phi->init_req(1, __ SubI(__ intcon(0), arg));
1250 size->init_req(1, __ intcon(1));
1251 r->init_req(2, greaterequal);
1252 phi->init_req(2, arg);
1253 size->init_req(2, __ intcon(0));
1254 kit.set_control(r);
1255 C->record_for_igvn(r);
1256 C->record_for_igvn(phi);
1257 C->record_for_igvn(size);
1258
1259 // for (int i=0; ; i++)
1260 // if (x <= sizeTable[i])
1261 // return i+1;
1262
1263 // Add loop predicate first.
1264 kit.add_empty_predicates();
1265 C->set_has_loops(true);
1266
1267 RegionNode *loop = new RegionNode(3);
1268 loop->init_req(1, kit.control());
1269 kit.gvn().set_type(loop, Type::CONTROL);
1270
1271 Node *index = new PhiNode(loop, TypeInt::INT);
1272 index->init_req(1, __ intcon(0));
1273 kit.gvn().set_type(index, TypeInt::INT);
1274 kit.set_control(loop);
1275 Node* sizeTable = fetch_static_field(kit, size_table_field);
1276
1277 Node* value = kit.load_array_element(sizeTable, index, TypeAryPtr::INTS, /* set_ctrl */ false);
1278 C->record_for_igvn(value);
1279 Node* limit = __ CmpI(phi, value);
1280 Node* limitb = __ Bool(limit, BoolTest::le);
1281 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1282 Node* lessEqual = __ IfTrue(iff2);
1283 Node* greater = __ IfFalse(iff2);
1284
1285 loop->init_req(2, greater);
1286 index->init_req(2, __ AddI(index, __ intcon(1)));
1287
1288 kit.set_control(lessEqual);
1289 C->record_for_igvn(loop);
1290 C->record_for_igvn(index);
1291
1292 final_merge->init_req(2, kit.control());
1293 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1294 }
1295
1296 kit.set_control(final_merge);
1297 C->record_for_igvn(final_merge);
1298 C->record_for_igvn(final_size);
1299
1300 return final_size;
1301 }
1302
1303 // Simplified version of Integer.getChars
1304 void PhaseStringOpts::getChars(GraphKit& kit, Node* arg, Node* dst_array, BasicType bt, Node* end, Node* final_merge, Node* final_mem, int merge_index) {
1305 // if (i < 0) {
1306 // sign = '-';
1307 // i = -i;
1308 // }
1309 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1310 PROB_FAIR, COUNT_UNKNOWN);
1311
1312 RegionNode* merge = new RegionNode(3);
1313 kit.gvn().set_type(merge, Type::CONTROL);
1314 Node* i = new PhiNode(merge, TypeInt::INT);
1315 kit.gvn().set_type(i, TypeInt::INT);
1316 Node* sign = new PhiNode(merge, TypeInt::INT);
1317 kit.gvn().set_type(sign, TypeInt::INT);
1318
1319 merge->init_req(1, __ IfTrue(iff));
1320 i->init_req(1, __ SubI(__ intcon(0), arg));
1321 sign->init_req(1, __ intcon('-'));
1322 merge->init_req(2, __ IfFalse(iff));
1323 i->init_req(2, arg);
1324 sign->init_req(2, __ intcon(0));
1325
1326 kit.set_control(merge);
1327
1328 C->record_for_igvn(merge);
1329 C->record_for_igvn(i);
1330 C->record_for_igvn(sign);
1331
1332 // for (;;) {
1333 // q = i / 10;
1334 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1335 // buf [--charPos] = digits [r];
1336 // i = q;
1337 // if (i == 0) break;
1338 // }
1339
1340 // Add loop predicate first.
1341 kit.add_empty_predicates();
1342
1343 C->set_has_loops(true);
1344 RegionNode* head = new RegionNode(3);
1345 head->init_req(1, kit.control());
1346
1347 kit.gvn().set_type(head, Type::CONTROL);
1348 Node* i_phi = new PhiNode(head, TypeInt::INT);
1349 i_phi->init_req(1, i);
1350 kit.gvn().set_type(i_phi, TypeInt::INT);
1351 Node* charPos = new PhiNode(head, TypeInt::INT);
1352 charPos->init_req(1, end);
1353 kit.gvn().set_type(charPos, TypeInt::INT);
1354 Node* mem = PhiNode::make(head, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1355 kit.gvn().set_type(mem, Type::MEMORY);
1356
1357 kit.set_control(head);
1358 kit.set_memory(mem, byte_adr_idx);
1359
1360 Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));
1361 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1362 __ LShiftI(q, __ intcon(1))));
1363 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1364 Node* ch = __ AddI(r, __ intcon('0'));
1365 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1366 ch, bt, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1367 false /* unaligned */, (bt != T_BYTE) /* mismatched */);
1368
1369 iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1370 PROB_FAIR, COUNT_UNKNOWN);
1371 Node* ne = __ IfTrue(iff);
1372 Node* eq = __ IfFalse(iff);
1373
1374 head->init_req(2, ne);
1375 mem->init_req(2, st);
1376
1377 i_phi->init_req(2, q);
1378 charPos->init_req(2, index);
1379 charPos = index;
1380
1381 kit.set_control(eq);
1382 kit.set_memory(st, byte_adr_idx);
1383
1384 C->record_for_igvn(head);
1385 C->record_for_igvn(mem);
1386 C->record_for_igvn(i_phi);
1387 C->record_for_igvn(charPos);
1388
1389 // if (sign != 0) {
1390 // buf [--charPos] = sign;
1391 // }
1392 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1393 PROB_FAIR, COUNT_UNKNOWN);
1394
1395 final_merge->init_req(merge_index + 2, __ IfFalse(iff));
1396 final_mem->init_req(merge_index + 2, kit.memory(byte_adr_idx));
1397
1398 kit.set_control(__ IfTrue(iff));
1399 if (kit.stopped()) {
1400 final_merge->init_req(merge_index + 1, C->top());
1401 final_mem->init_req(merge_index + 1, C->top());
1402 } else {
1403 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1404 st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1405 sign, bt, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1406 false /* unaligned */, (bt != T_BYTE) /* mismatched */);
1407
1408 final_merge->init_req(merge_index + 1, kit.control());
1409 final_mem->init_req(merge_index + 1, st);
1410 }
1411 }
1412
1413 // Copy the characters representing arg into dst_array starting at start
1414 Node* PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* dst_array, Node* dst_coder, Node* start, Node* size) {
1415 bool dcon = dst_coder->is_Con();
1416 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1417 Node* end = __ AddI(start, __ LShiftI(size, dst_coder));
1418
1419 // The final_merge node has 4 entries in case the encoding is known:
1420 // (0) Control, (1) result w/ sign, (2) result w/o sign, (3) result for Integer.min_value
1421 // or 6 entries in case the encoding is not known:
1422 // (0) Control, (1) Latin1 w/ sign, (2) Latin1 w/o sign, (3) min_value, (4) UTF16 w/ sign, (5) UTF16 w/o sign
1423 RegionNode* final_merge = new RegionNode(dcon ? 4 : 6);
1424 kit.gvn().set_type(final_merge, Type::CONTROL);
1425
1426 Node* final_mem = PhiNode::make(final_merge, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1427 kit.gvn().set_type(final_mem, Type::MEMORY);
1428
1429 // need to handle arg == Integer.MIN_VALUE specially because negating doesn't make it positive
1430 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1431 PROB_FAIR, COUNT_UNKNOWN);
1432
1433 Node* old_mem = kit.memory(byte_adr_idx);
1434
1435 kit.set_control(__ IfFalse(iff));
1436 if (kit.stopped()) {
1437 // Statically not equal to MIN_VALUE so this path is dead
1438 final_merge->init_req(3, kit.control());
1439 } else {
1440 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1441 dst_array, dst_coder, start);
1442 final_merge->init_req(3, kit.control());
1443 final_mem->init_req(3, kit.memory(byte_adr_idx));
1444 }
1445
1446 kit.set_control(__ IfTrue(iff));
1447 kit.set_memory(old_mem, byte_adr_idx);
1448
1449 if (!dcon) {
1450 // Check encoding of destination
1451 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(dst_coder, __ intcon(0)), BoolTest::eq),
1452 PROB_FAIR, COUNT_UNKNOWN);
1453 old_mem = kit.memory(byte_adr_idx);
1454 }
1455 if (!dcon || dbyte) {
1456 // Destination is Latin1,
1457 if (!dcon) {
1458 kit.set_control(__ IfTrue(iff));
1459 }
1460 getChars(kit, arg, dst_array, T_BYTE, end, final_merge, final_mem);
1461 }
1462 if (!dcon || !dbyte) {
1463 // Destination is UTF16
1464 int merge_index = 0;
1465 if (!dcon) {
1466 kit.set_control(__ IfFalse(iff));
1467 kit.set_memory(old_mem, byte_adr_idx);
1468 merge_index = 3; // Account for Latin1 case
1469 }
1470 getChars(kit, arg, dst_array, T_CHAR, end, final_merge, final_mem, merge_index);
1471 }
1472
1473 // Final merge point for Latin1 and UTF16 case
1474 kit.set_control(final_merge);
1475 kit.set_memory(final_mem, byte_adr_idx);
1476
1477 C->record_for_igvn(final_merge);
1478 C->record_for_igvn(final_mem);
1479 return end;
1480 }
1481
1482 // Copy 'count' bytes/chars from src_array to dst_array starting at index start
1483 void PhaseStringOpts::arraycopy(GraphKit& kit, IdealKit& ideal, Node* src_array, Node* dst_array, BasicType elembt, Node* start, Node* count) {
1484 assert(elembt == T_BYTE || elembt == T_CHAR, "Invalid type for arraycopy");
1485
1486 if (elembt == T_CHAR) {
1487 // Get number of chars
1488 count = __ RShiftI(count, __ intcon(1));
1489 }
1490
1491 Node* extra = NULL;
1492 #ifdef _LP64
1493 count = __ ConvI2L(count);
1494 extra = C->top();
1495 #endif
1496
1497 Node* src_ptr = __ array_element_address(src_array, __ intcon(0), T_BYTE);
1498 Node* dst_ptr = __ array_element_address(dst_array, start, T_BYTE);
1499 // Check if destination address is aligned to HeapWordSize
1500 const TypeInt* tdst = __ gvn().type(start)->is_int();
1501 bool aligned = tdst->is_con() && ((tdst->get_con() * type2aelembytes(T_BYTE)) % HeapWordSize == 0);
1502 // Figure out which arraycopy runtime method to call (disjoint, uninitialized).
1503 const char* copyfunc_name = "arraycopy";
1504 address copyfunc_addr = StubRoutines::select_arraycopy_function(elembt, aligned, true, copyfunc_name, true);
1505 ideal.make_leaf_call_no_fp(OptoRuntime::fast_arraycopy_Type(), copyfunc_addr, copyfunc_name,
1506 TypeAryPtr::BYTES, src_ptr, dst_ptr, count, extra);
1507 }
1508
1509 #undef __
1510 #define __ ideal.
1511
1512 // Copy contents of a Latin1 encoded string from src_array to dst_array
1513 void PhaseStringOpts::copy_latin1_string(GraphKit& kit, IdealKit& ideal, Node* src_array, IdealVariable& count,
1514 Node* dst_array, Node* dst_coder, Node* start) {
1515 bool dcon = dst_coder->is_Con();
1516 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1517
1518 if (!dcon) {
1519 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1520 }
1521 if (!dcon || dbyte) {
1522 // Destination is Latin1. Simply emit a byte arraycopy.
1523 arraycopy(kit, ideal, src_array, dst_array, T_BYTE, start, __ value(count));
1524 }
1525 if (!dcon) {
1526 __ else_();
1527 }
1528 if (!dcon || !dbyte) {
1529 // Destination is UTF16. Inflate src_array into dst_array.
1530 kit.sync_kit(ideal);
1531 if (Matcher::match_rule_supported(Op_StrInflatedCopy)) {
1532 // Use fast intrinsic
1533 Node* src = kit.array_element_address(src_array, kit.intcon(0), T_BYTE);
1534 Node* dst = kit.array_element_address(dst_array, start, T_BYTE);
1535 kit.inflate_string(src, dst, TypeAryPtr::BYTES, __ value(count));
1536 } else {
1537 // No intrinsic available, use slow method
1538 kit.inflate_string_slow(src_array, dst_array, start, __ value(count));
1539 }
1540 ideal.sync_kit(&kit);
1541 // Multiply count by two since we now need two bytes per char
1542 __ set(count, __ LShiftI(__ value(count), __ ConI(1)));
1543 }
1544 if (!dcon) {
1545 __ end_if();
1546 }
1547 }
1548
1549 // Read two bytes from index and index+1 and convert them to a char
1550 static jchar readChar(ciTypeArray* array, int index) {
1551 int shift_high, shift_low;
1552 #ifdef VM_LITTLE_ENDIAN
1553 shift_high = 0;
1554 shift_low = 8;
1555 #else
1556 shift_high = 8;
1557 shift_low = 0;
1558 #endif
1559
1560 jchar b1 = ((jchar) array->byte_at(index)) & 0xff;
1561 jchar b2 = ((jchar) array->byte_at(index+1)) & 0xff;
1562 return (b1 << shift_high) | (b2 << shift_low);
1563 }
1564
1565 // Copy contents of constant src_array to dst_array by emitting individual stores
1566 void PhaseStringOpts::copy_constant_string(GraphKit& kit, IdealKit& ideal, ciTypeArray* src_array, IdealVariable& count,
1567 bool src_is_byte, Node* dst_array, Node* dst_coder, Node* start) {
1568 bool dcon = dst_coder->is_Con();
1569 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1570 int length = src_array->length();
1571
1572 if (!dcon) {
1573 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1574 }
1575 if (!dcon || dbyte) {
1576 // Destination is Latin1. Copy each byte of src_array into dst_array.
1577 Node* index = start;
1578 for (int i = 0; i < length; i++) {
1579 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1580 Node* val = __ ConI(src_array->byte_at(i));
1581 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1582 index = __ AddI(index, __ ConI(1));
1583 }
1584 }
1585 if (!dcon) {
1586 __ else_();
1587 }
1588 if (!dcon || !dbyte) {
1589 // Destination is UTF16. Copy each char of src_array into dst_array.
1590 Node* index = start;
1591 for (int i = 0; i < length; i++) {
1592 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1593 jchar val;
1594 if (src_is_byte) {
1595 val = src_array->byte_at(i) & 0xff;
1596 } else {
1597 val = readChar(src_array, i++);
1598 }
1599 __ store(__ ctrl(), adr, __ ConI(val), T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1600 true /* mismatched */);
1601 index = __ AddI(index, __ ConI(2));
1602 }
1603 if (src_is_byte) {
1604 // Multiply count by two since we now need two bytes per char
1605 __ set(count, __ ConI(2 * length));
1606 }
1607 }
1608 if (!dcon) {
1609 __ end_if();
1610 }
1611 }
1612
1613 // Compress copy contents of the byte/char String str into dst_array starting at index start.
1614 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* dst_array, Node* dst_coder, Node* start) {
1615 Node* src_array = kit.load_String_value(str, true);
1616
1617 IdealKit ideal(&kit, true, true);
1618 IdealVariable count(ideal); __ declarations_done();
1619
1620 if (str->is_Con()) {
1621 // Constant source string
1622 ciTypeArray* src_array_type = get_constant_value(kit, str);
1623
1624 // Check encoding of constant string
1625 bool src_is_byte = (get_constant_coder(kit, str) == java_lang_String::CODER_LATIN1);
1626
1627 // For small constant strings just emit individual stores.
1628 // A length of 6 seems like a good space/speed tradeof.
1629 __ set(count, __ ConI(src_array_type->length()));
1630 int src_len = src_array_type->length() / (src_is_byte ? 1 : 2);
1631 if (src_len < unroll_string_copy_length) {
1632 // Small constant string
1633 copy_constant_string(kit, ideal, src_array_type, count, src_is_byte, dst_array, dst_coder, start);
1634 } else if (src_is_byte) {
1635 // Source is Latin1
1636 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1637 } else {
1638 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1639 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1640 }
1641 } else {
1642 Node* size = kit.load_array_length(src_array);
1643 __ set(count, size);
1644 // Non-constant source string
1645 if (CompactStrings) {
1646 // Emit runtime check for coder
1647 Node* coder = kit.load_String_coder(str, true);
1648 __ if_then(coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1)); {
1649 // Source is Latin1
1650 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1651 } __ else_();
1652 }
1653 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1654 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1655
1656 if (CompactStrings) {
1657 __ end_if();
1658 }
1659 }
1660
1661 // Finally sync IdealKit and GraphKit.
1662 kit.sync_kit(ideal);
1663 return __ AddI(start, __ value(count));
1664 }
1665
1666 // Compress copy the char into dst_array at index start.
1667 Node* PhaseStringOpts::copy_char(GraphKit& kit, Node* val, Node* dst_array, Node* dst_coder, Node* start) {
1668 bool dcon = (dst_coder != NULL) && dst_coder->is_Con();
1669 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1670
1671 IdealKit ideal(&kit, true, true);
1672 IdealVariable end(ideal); __ declarations_done();
1673 Node* adr = kit.array_element_address(dst_array, start, T_BYTE);
1674 if (!dcon){
1675 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1676 }
1677 if (!dcon || dbyte) {
1678 // Destination is Latin1. Store a byte.
1679 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1680 __ set(end, __ AddI(start, __ ConI(1)));
1681 }
1682 if (!dcon) {
1683 __ else_();
1684 }
1685 if (!dcon || !dbyte) {
1686 // Destination is UTF16. Store a char.
1687 __ store(__ ctrl(), adr, val, T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1688 true /* mismatched */);
1689 __ set(end, __ AddI(start, __ ConI(2)));
1690 }
1691 if (!dcon) {
1692 __ end_if();
1693 }
1694 // Finally sync IdealKit and GraphKit.
1695 kit.sync_kit(ideal);
1696 return __ value(end);
1697 }
1698
1699 #undef __
1700 #define __ kit.
1701
1702 // Allocate a byte array of specified length.
1703 Node* PhaseStringOpts::allocate_byte_array(GraphKit& kit, IdealKit* ideal, Node* length) {
1704 if (ideal != NULL) {
1705 // Sync IdealKit and graphKit.
1706 kit.sync_kit(*ideal);
1707 }
1708 Node* byte_array = NULL;
1709 {
1710 PreserveReexecuteState preexecs(&kit);
1711 // The original jvms is for an allocation of either a String or
1712 // StringBuffer so no stack adjustment is necessary for proper
1713 // reexecution. If we deoptimize in the slow path the bytecode
1714 // will be reexecuted and the char[] allocation will be thrown away.
1715 kit.jvms()->set_should_reexecute(true);
1716 byte_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_BYTE))),
1717 length, 1);
1718 }
1719
1720 // Mark the allocation so that zeroing is skipped since the code
1721 // below will overwrite the entire array
1722 AllocateArrayNode* byte_alloc = AllocateArrayNode::Ideal_array_allocation(byte_array, _gvn);
1723 byte_alloc->maybe_set_complete(_gvn);
1724
1725 if (ideal != NULL) {
1726 // Sync IdealKit and graphKit.
1727 ideal->sync_kit(&kit);
1728 }
1729 return byte_array;
1730 }
1731
1732 jbyte PhaseStringOpts::get_constant_coder(GraphKit& kit, Node* str) {
1733 assert(str->is_Con(), "String must be constant");
1734 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1735 ciInstance* str_instance = str_type->const_oop()->as_instance();
1736 jbyte coder = str_instance->field_value_by_offset(java_lang_String::coder_offset()).as_byte();
1737 assert(CompactStrings || (coder == java_lang_String::CODER_UTF16), "Strings must be UTF16 encoded");
1738 return coder;
1739 }
1740
1741 int PhaseStringOpts::get_constant_length(GraphKit& kit, Node* str) {
1742 assert(str->is_Con(), "String must be constant");
1743 return get_constant_value(kit, str)->length();
1744 }
1745
1746 ciTypeArray* PhaseStringOpts::get_constant_value(GraphKit& kit, Node* str) {
1747 assert(str->is_Con(), "String must be constant");
1748 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1749 ciInstance* str_instance = str_type->const_oop()->as_instance();
1750 ciObject* src_array = str_instance->field_value_by_offset(java_lang_String::value_offset()).as_object();
1751 return src_array->as_type_array();
1752 }
1753
1754 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1755 // Log a little info about the transformation
1756 sc->maybe_log_transform();
1757
1758 // pull the JVMState of the allocation into a SafePointNode to serve as
1759 // as a shim for the insertion of the new code.
1760 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1761 uint size = sc->begin()->req();
1762 SafePointNode* map = new SafePointNode(size, jvms);
1763
1764 // copy the control and memory state from the final call into our
1765 // new starting state. This allows any preceeding tests to feed
1766 // into the new section of code.
1767 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1768 map->init_req(i1, sc->end()->in(i1));
1769 }
1770 // blow away old allocation arguments
1771 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1772 map->init_req(i1, C->top());
1773 }
1774 // Copy the rest of the inputs for the JVMState
1775 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1776 map->init_req(i1, sc->begin()->in(i1));
1777 }
1778 // Make sure the memory state is a MergeMem for parsing.
1779 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1780 map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory)));
1781 }
1782
1783 jvms->set_map(map);
1784 map->ensure_stack(jvms, jvms->method()->max_stack());
1785
1786 // disconnect all the old StringBuilder calls from the graph
1787 sc->eliminate_unneeded_control();
1788
1789 // At this point all the old work has been completely removed from
1790 // the graph and the saved JVMState exists at the point where the
1791 // final toString call used to be.
1792 GraphKit kit(jvms);
1793
1794 // There may be uncommon traps which are still using the
1795 // intermediate states and these need to be rewritten to point at
1796 // the JVMState at the beginning of the transformation.
1797 sc->convert_uncommon_traps(kit, jvms);
1798
1799 // Now insert the logic to compute the size of the string followed
1800 // by all the logic to construct array and resulting string.
1801
1802 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1803
1804 // Create a region for the overflow checks to merge into.
1805 int args = MAX2(sc->num_arguments(), 1);
1806 RegionNode* overflow = new RegionNode(args);
1807 kit.gvn().set_type(overflow, Type::CONTROL);
1808
1809 // Create a hook node to hold onto the individual sizes since they
1810 // are need for the copying phase.
1811 Node* string_sizes = new Node(args);
1812
1813 Node* coder = __ intcon(0);
1814 Node* length = __ intcon(0);
1815 // If at least one argument is UTF16 encoded, we can fix the encoding.
1816 bool coder_fixed = false;
1817
1818 if (!CompactStrings) {
1819 // Fix encoding of result string to UTF16
1820 coder_fixed = true;
1821 coder = __ intcon(java_lang_String::CODER_UTF16);
1822 }
1823
1824 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1825 Node* arg = sc->argument(argi);
1826 switch (sc->mode(argi)) {
1827 case StringConcat::NegativeIntCheckMode: {
1828 // Initial capacity argument might be negative in which case StringBuilder(int) throws
1829 // a NegativeArraySizeException. Insert a runtime check with an uncommon trap.
1830 const TypeInt* type = kit.gvn().type(arg)->is_int();
1831 assert(type->_hi >= 0 && type->_lo < 0, "no runtime int check needed");
1832 Node* p = __ Bool(__ CmpI(arg, kit.intcon(0)), BoolTest::ge);
1833 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1834 {
1835 // Negative int -> uncommon trap.
1836 PreserveJVMState pjvms(&kit);
1837 kit.set_control(__ IfFalse(iff));
1838 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1839 Deoptimization::Action_maybe_recompile);
1840 }
1841 kit.set_control(__ IfTrue(iff));
1842 break;
1843 }
1844 case StringConcat::IntMode: {
1845 Node* string_size = int_stringSize(kit, arg);
1846
1847 // accumulate total
1848 length = __ AddI(length, string_size);
1849
1850 // Cache this value for the use by int_toString
1851 string_sizes->init_req(argi, string_size);
1852 break;
1853 }
1854 case StringConcat::StringNullCheckMode: {
1855 const Type* type = kit.gvn().type(arg);
1856 assert(type != TypePtr::NULL_PTR, "missing check");
1857 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1858 // Null check with uncommon trap since
1859 // StringBuilder(null) throws exception.
1860 // Use special uncommon trap instead of
1861 // calling normal do_null_check().
1862 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1863 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1864 overflow->add_req(__ IfFalse(iff));
1865 Node* notnull = __ IfTrue(iff);
1866 kit.set_control(notnull); // set control for the cast_not_null
1867 arg = kit.cast_not_null(arg, false);
1868 sc->set_argument(argi, arg);
1869 }
1870 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1871 // Fallthrough to add string length.
1872 }
1873 case StringConcat::StringMode: {
1874 const Type* type = kit.gvn().type(arg);
1875 Node* count = NULL;
1876 Node* arg_coder = NULL;
1877 if (type == TypePtr::NULL_PTR) {
1878 // replace the argument with the null checked version
1879 arg = null_string;
1880 sc->set_argument(argi, arg);
1881 count = kit.load_String_length(arg, true);
1882 arg_coder = kit.load_String_coder(arg, true);
1883 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1884 // s = s != null ? s : "null";
1885 // length = length + (s.count - s.offset);
1886 RegionNode *r = new RegionNode(3);
1887 kit.gvn().set_type(r, Type::CONTROL);
1888 Node *phi = new PhiNode(r, type);
1889 kit.gvn().set_type(phi, phi->bottom_type());
1890 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1891 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1892 Node* notnull = __ IfTrue(iff);
1893 Node* isnull = __ IfFalse(iff);
1894 kit.set_control(notnull); // set control for the cast_not_null
1895 r->init_req(1, notnull);
1896 phi->init_req(1, kit.cast_not_null(arg, false));
1897 r->init_req(2, isnull);
1898 phi->init_req(2, null_string);
1899 kit.set_control(r);
1900 C->record_for_igvn(r);
1901 C->record_for_igvn(phi);
1902 // replace the argument with the null checked version
1903 arg = phi;
1904 sc->set_argument(argi, arg);
1905 count = kit.load_String_length(arg, true);
1906 arg_coder = kit.load_String_coder(arg, true);
1907 } else {
1908 // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP
1909 // kit.control might be a different test, that can be hoisted above the actual nullcheck
1910 // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck.
1911 count = kit.load_String_length(arg, false);
1912 arg_coder = kit.load_String_coder(arg, false);
1913 }
1914 if (arg->is_Con()) {
1915 // Constant string. Get constant coder and length.
1916 jbyte const_coder = get_constant_coder(kit, arg);
1917 int const_length = get_constant_length(kit, arg);
1918 if (const_coder == java_lang_String::CODER_LATIN1) {
1919 // Can be latin1 encoded
1920 arg_coder = __ intcon(const_coder);
1921 count = __ intcon(const_length);
1922 } else {
1923 // Found UTF16 encoded string. Fix result array encoding to UTF16.
1924 coder_fixed = true;
1925 coder = __ intcon(const_coder);
1926 count = __ intcon(const_length / 2);
1927 }
1928 }
1929
1930 if (!coder_fixed) {
1931 coder = __ OrI(coder, arg_coder);
1932 }
1933 length = __ AddI(length, count);
1934 string_sizes->init_req(argi, NULL);
1935 break;
1936 }
1937 case StringConcat::CharMode: {
1938 // one character only
1939 const TypeInt* t = kit.gvn().type(arg)->is_int();
1940 if (!coder_fixed && t->is_con()) {
1941 // Constant char
1942 if (t->get_con() <= 255) {
1943 // Can be latin1 encoded
1944 coder = __ OrI(coder, __ intcon(java_lang_String::CODER_LATIN1));
1945 } else {
1946 // Must be UTF16 encoded. Fix result array encoding to UTF16.
1947 coder_fixed = true;
1948 coder = __ intcon(java_lang_String::CODER_UTF16);
1949 }
1950 } else if (!coder_fixed) {
1951 // Not constant
1952 #undef __
1953 #define __ ideal.
1954 IdealKit ideal(&kit, true, true);
1955 IdealVariable char_coder(ideal); __ declarations_done();
1956 // Check if character can be latin1 encoded
1957 __ if_then(arg, BoolTest::le, __ ConI(0xFF));
1958 __ set(char_coder, __ ConI(java_lang_String::CODER_LATIN1));
1959 __ else_();
1960 __ set(char_coder, __ ConI(java_lang_String::CODER_UTF16));
1961 __ end_if();
1962 kit.sync_kit(ideal);
1963 coder = __ OrI(coder, __ value(char_coder));
1964 #undef __
1965 #define __ kit.
1966 }
1967 length = __ AddI(length, __ intcon(1));
1968 break;
1969 }
1970 default:
1971 ShouldNotReachHere();
1972 }
1973 if (argi > 0) {
1974 // Check that the sum hasn't overflowed
1975 IfNode* iff = kit.create_and_map_if(kit.control(),
1976 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1977 PROB_MIN, COUNT_UNKNOWN);
1978 kit.set_control(__ IfFalse(iff));
1979 overflow->set_req(argi, __ IfTrue(iff));
1980 }
1981 }
1982
1983 {
1984 // Hook
1985 PreserveJVMState pjvms(&kit);
1986 kit.set_control(overflow);
1987 C->record_for_igvn(overflow);
1988 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1989 Deoptimization::Action_make_not_entrant);
1990 }
1991
1992 Node* result;
1993 if (!kit.stopped()) {
1994 assert(CompactStrings || (coder->is_Con() && coder->get_int() == java_lang_String::CODER_UTF16),
1995 "Result string must be UTF16 encoded if CompactStrings is disabled");
1996
1997 Node* dst_array = NULL;
1998 if (sc->num_arguments() == 1 &&
1999 (sc->mode(0) == StringConcat::StringMode ||
2000 sc->mode(0) == StringConcat::StringNullCheckMode)) {
2001 // Handle the case when there is only a single String argument.
2002 // In this case, we can just pull the value from the String itself.
2003 dst_array = kit.load_String_value(sc->argument(0), true);
2004 } else {
2005 // Allocate destination byte array according to coder
2006 dst_array = allocate_byte_array(kit, NULL, __ LShiftI(length, coder));
2007
2008 // Now copy the string representations into the final byte[]
2009 Node* start = __ intcon(0);
2010 for (int argi = 0; argi < sc->num_arguments(); argi++) {
2011 Node* arg = sc->argument(argi);
2012 switch (sc->mode(argi)) {
2013 case StringConcat::NegativeIntCheckMode:
2014 break; // Nothing to do, was only needed to add a runtime check earlier.
2015 case StringConcat::IntMode: {
2016 start = int_getChars(kit, arg, dst_array, coder, start, string_sizes->in(argi));
2017 break;
2018 }
2019 case StringConcat::StringNullCheckMode:
2020 case StringConcat::StringMode: {
2021 start = copy_string(kit, arg, dst_array, coder, start);
2022 break;
2023 }
2024 case StringConcat::CharMode: {
2025 start = copy_char(kit, arg, dst_array, coder, start);
2026 break;
2027 }
2028 default:
2029 ShouldNotReachHere();
2030 }
2031 }
2032 }
2033
2034 // If we're not reusing an existing String allocation then allocate one here.
2035 result = sc->string_alloc();
2036 if (result == NULL) {
2037 PreserveReexecuteState preexecs(&kit);
2038 // The original jvms is for an allocation of either a String or
2039 // StringBuffer so no stack adjustment is necessary for proper
2040 // reexecution.
2041 kit.jvms()->set_should_reexecute(true);
2042 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
2043 }
2044
2045 // Initialize the string
2046 kit.store_String_value(result, dst_array);
2047 kit.store_String_coder(result, coder);
2048
2049 // The value field is final. Emit a barrier here to ensure that the effect
2050 // of the initialization is committed to memory before any code publishes
2051 // a reference to the newly constructed object (see Parse::do_exits()).
2052 assert(AllocateNode::Ideal_allocation(result, _gvn) != NULL, "should be newly allocated");
2053 kit.insert_mem_bar(Op_MemBarRelease, result);
2054 } else {
2055 result = C->top();
2056 }
2057 // hook up the outgoing control and result
2058 kit.replace_call(sc->end(), result);
2059
2060 // Unhook any hook nodes
2061 string_sizes->disconnect_inputs(C);
2062 sc->cleanup();
2063 }