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 "classfile/javaClasses.hpp"
27 #include "compiler/compileLog.hpp"
28 #include "opto/addnode.hpp"
29 #include "opto/callGenerator.hpp"
30 #include "opto/callnode.hpp"
31 #include "opto/divnode.hpp"
32 #include "opto/graphKit.hpp"
33 #include "opto/idealKit.hpp"
34 #include "opto/rootnode.hpp"
35 #include "opto/runtime.hpp"
36 #include "opto/stringopts.hpp"
37 #include "opto/subnode.hpp"
38 #include "runtime/sharedRuntime.hpp"
39
40 #define __ kit.
41
42 class StringConcat : public ResourceObj {
43 private:
44 PhaseStringOpts* _stringopts;
45 Node* _string_alloc;
46 AllocateNode* _begin; // The allocation the begins the pattern
47 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
48 // SB.toString or or String.<init>(SB.toString)
49 bool _multiple; // indicates this is a fusion of two or more
50 // separate StringBuilders
51
52 Node* _arguments; // The list of arguments to be concatenated
53 GrowableArray<int> _mode; // into a String along with a mode flag
54 // indicating how to treat the value.
55 Node_List _constructors; // List of constructors (many in case of stacked concat)
56 Node_List _control; // List of control nodes that will be deleted
57 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
58 // to restart at the initial JVMState.
59
60 public:
61 // Mode for converting arguments to Strings
62 enum {
63 StringMode,
64 IntMode,
65 CharMode,
66 StringNullCheckMode
67 };
68
StringConcat(PhaseStringOpts * stringopts,CallStaticJavaNode * end)69 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
70 _stringopts(stringopts),
71 _string_alloc(NULL),
72 _begin(NULL),
73 _end(end),
74 _multiple(false) {
75 _arguments = new Node(1);
76 _arguments->del_req(0);
77 }
78
79 bool validate_mem_flow();
80 bool validate_control_flow();
81
merge_add()82 void merge_add() {
83 #if 0
84 // XXX This is place holder code for reusing an existing String
85 // allocation but the logic for checking the state safety is
86 // probably inadequate at the moment.
87 CallProjections endprojs;
88 sc->end()->extract_projections(&endprojs, false);
89 if (endprojs.resproj != NULL) {
90 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
91 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
92 if (use != NULL && use->method() != NULL &&
93 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
94 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
95 // Found useless new String(sb.toString()) so reuse the newly allocated String
96 // when creating the result instead of allocating a new one.
97 sc->set_string_alloc(use->in(TypeFunc::Parms));
98 sc->set_end(use);
99 }
100 }
101 }
102 #endif
103 }
104
105 StringConcat* merge(StringConcat* other, Node* arg);
106
set_allocation(AllocateNode * alloc)107 void set_allocation(AllocateNode* alloc) {
108 _begin = alloc;
109 }
110
append(Node * value,int mode)111 void append(Node* value, int mode) {
112 _arguments->add_req(value);
113 _mode.append(mode);
114 }
push(Node * value,int mode)115 void push(Node* value, int mode) {
116 _arguments->ins_req(0, value);
117 _mode.insert_before(0, mode);
118 }
119
push_string(Node * value)120 void push_string(Node* value) {
121 push(value, StringMode);
122 }
push_string_null_check(Node * value)123 void push_string_null_check(Node* value) {
124 push(value, StringNullCheckMode);
125 }
push_int(Node * value)126 void push_int(Node* value) {
127 push(value, IntMode);
128 }
push_char(Node * value)129 void push_char(Node* value) {
130 push(value, CharMode);
131 }
132
is_SB_toString(Node * call)133 static bool is_SB_toString(Node* call) {
134 if (call->is_CallStaticJava()) {
135 CallStaticJavaNode* csj = call->as_CallStaticJava();
136 ciMethod* m = csj->method();
137 if (m != NULL &&
138 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
139 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
140 return true;
141 }
142 }
143 return false;
144 }
145
skip_string_null_check(Node * value)146 static Node* skip_string_null_check(Node* value) {
147 // Look for a diamond shaped Null check of toString() result
148 // (could be code from String.valueOf()):
149 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
150 if (value->is_Phi()) {
151 int true_path = value->as_Phi()->is_diamond_phi();
152 if (true_path != 0) {
153 // phi->region->if_proj->ifnode->bool
154 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
155 Node* cmp = b->in(1);
156 Node* v1 = cmp->in(1);
157 Node* v2 = cmp->in(2);
158 // Null check of the return of toString which can simply be skipped.
159 if (b->_test._test == BoolTest::ne &&
160 v2->bottom_type() == TypePtr::NULL_PTR &&
161 value->in(true_path)->Opcode() == Op_CastPP &&
162 value->in(true_path)->in(1) == v1 &&
163 v1->is_Proj() && is_SB_toString(v1->in(0))) {
164 return v1;
165 }
166 }
167 }
168 return value;
169 }
170
argument(int i)171 Node* argument(int i) {
172 return _arguments->in(i);
173 }
argument_uncast(int i)174 Node* argument_uncast(int i) {
175 Node* arg = argument(i);
176 int amode = mode(i);
177 if (amode == StringConcat::StringMode ||
178 amode == StringConcat::StringNullCheckMode) {
179 arg = skip_string_null_check(arg);
180 }
181 return arg;
182 }
set_argument(int i,Node * value)183 void set_argument(int i, Node* value) {
184 _arguments->set_req(i, value);
185 }
num_arguments()186 int num_arguments() {
187 return _mode.length();
188 }
mode(int i)189 int mode(int i) {
190 return _mode.at(i);
191 }
add_control(Node * ctrl)192 void add_control(Node* ctrl) {
193 assert(!_control.contains(ctrl), "only push once");
194 _control.push(ctrl);
195 }
add_constructor(Node * init)196 void add_constructor(Node* init) {
197 assert(!_constructors.contains(init), "only push once");
198 _constructors.push(init);
199 }
end()200 CallStaticJavaNode* end() { return _end; }
begin()201 AllocateNode* begin() { return _begin; }
string_alloc()202 Node* string_alloc() { return _string_alloc; }
203
204 void eliminate_unneeded_control();
205 void eliminate_initialize(InitializeNode* init);
206 void eliminate_call(CallNode* call);
207
maybe_log_transform()208 void maybe_log_transform() {
209 CompileLog* log = _stringopts->C->log();
210 if (log != NULL) {
211 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
212 num_arguments(),
213 _string_alloc != NULL,
214 _multiple);
215 JVMState* p = _begin->jvms();
216 while (p != NULL) {
217 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
218 p = p->caller();
219 }
220 log->tail("replace_string_concat");
221 }
222 }
223
convert_uncommon_traps(GraphKit & kit,const JVMState * jvms)224 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
225 for (uint u = 0; u < _uncommon_traps.size(); u++) {
226 Node* uct = _uncommon_traps.at(u);
227
228 // Build a new call using the jvms state of the allocate
229 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
230 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
231 const TypePtr* no_memory_effects = NULL;
232 Compile* C = _stringopts->C;
233 CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
234 jvms->bci(), no_memory_effects);
235 for (int e = 0; e < TypeFunc::Parms; e++) {
236 call->init_req(e, uct->in(e));
237 }
238 // Set the trap request to record intrinsic failure if this trap
239 // is taken too many times. Ideally we would handle then traps by
240 // doing the original bookkeeping in the MDO so that if it caused
241 // the code to be thrown out we could still recompile and use the
242 // optimization. Failing the uncommon traps doesn't really mean
243 // that the optimization is a bad idea but there's no other way to
244 // do the MDO updates currently.
245 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
246 Deoptimization::Action_make_not_entrant);
247 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
248 kit.add_safepoint_edges(call);
249
250 _stringopts->gvn()->transform(call);
251 C->gvn_replace_by(uct, call);
252 uct->disconnect_inputs(C);
253 }
254 }
255
cleanup()256 void cleanup() {
257 // disconnect the hook node
258 _arguments->disconnect_inputs(_stringopts->C);
259 }
260 };
261
262
eliminate_unneeded_control()263 void StringConcat::eliminate_unneeded_control() {
264 for (uint i = 0; i < _control.size(); i++) {
265 Node* n = _control.at(i);
266 if (n->is_Allocate()) {
267 eliminate_initialize(n->as_Allocate()->initialization());
268 }
269 if (n->is_Call()) {
270 if (n != _end) {
271 eliminate_call(n->as_Call());
272 }
273 } else if (n->is_IfTrue()) {
274 Compile* C = _stringopts->C;
275 C->gvn_replace_by(n, n->in(0)->in(0));
276 // get rid of the other projection
277 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
278 }
279 }
280 }
281
282
merge(StringConcat * other,Node * arg)283 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
284 StringConcat* result = new StringConcat(_stringopts, _end);
285 for (uint x = 0; x < _control.size(); x++) {
286 Node* n = _control.at(x);
287 if (n->is_Call()) {
288 result->_control.push(n);
289 }
290 }
291 for (uint x = 0; x < other->_control.size(); x++) {
292 Node* n = other->_control.at(x);
293 if (n->is_Call()) {
294 result->_control.push(n);
295 }
296 }
297 assert(result->_control.contains(other->_end), "what?");
298 assert(result->_control.contains(_begin), "what?");
299 for (int x = 0; x < num_arguments(); x++) {
300 Node* argx = argument_uncast(x);
301 if (argx == arg) {
302 // replace the toString result with the all the arguments that
303 // made up the other StringConcat
304 for (int y = 0; y < other->num_arguments(); y++) {
305 result->append(other->argument(y), other->mode(y));
306 }
307 } else {
308 result->append(argx, mode(x));
309 }
310 }
311 result->set_allocation(other->_begin);
312 for (uint i = 0; i < _constructors.size(); i++) {
313 result->add_constructor(_constructors.at(i));
314 }
315 for (uint i = 0; i < other->_constructors.size(); i++) {
316 result->add_constructor(other->_constructors.at(i));
317 }
318 result->_multiple = true;
319 return result;
320 }
321
322
eliminate_call(CallNode * call)323 void StringConcat::eliminate_call(CallNode* call) {
324 Compile* C = _stringopts->C;
325 CallProjections projs;
326 call->extract_projections(&projs, false);
327 if (projs.fallthrough_catchproj != NULL) {
328 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
329 }
330 if (projs.fallthrough_memproj != NULL) {
331 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
332 }
333 if (projs.catchall_memproj != NULL) {
334 C->gvn_replace_by(projs.catchall_memproj, C->top());
335 }
336 if (projs.fallthrough_ioproj != NULL) {
337 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
338 }
339 if (projs.catchall_ioproj != NULL) {
340 C->gvn_replace_by(projs.catchall_ioproj, C->top());
341 }
342 if (projs.catchall_catchproj != NULL) {
343 // EA can't cope with the partially collapsed graph this
344 // creates so put it on the worklist to be collapsed later.
345 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
346 Node *use = i.get();
347 int opc = use->Opcode();
348 if (opc == Op_CreateEx || opc == Op_Region) {
349 _stringopts->record_dead_node(use);
350 }
351 }
352 C->gvn_replace_by(projs.catchall_catchproj, C->top());
353 }
354 if (projs.resproj != NULL) {
355 C->gvn_replace_by(projs.resproj, C->top());
356 }
357 C->gvn_replace_by(call, C->top());
358 }
359
eliminate_initialize(InitializeNode * init)360 void StringConcat::eliminate_initialize(InitializeNode* init) {
361 Compile* C = _stringopts->C;
362
363 // Eliminate Initialize node.
364 assert(init->outcnt() <= 2, "only a control and memory projection expected");
365 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
366 Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
367 if (ctrl_proj != NULL) {
368 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
369 }
370 Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
371 if (mem_proj != NULL) {
372 Node *mem = init->in(TypeFunc::Memory);
373 C->gvn_replace_by(mem_proj, mem);
374 }
375 C->gvn_replace_by(init, C->top());
376 init->disconnect_inputs(C);
377 }
378
collect_toString_calls()379 Node_List PhaseStringOpts::collect_toString_calls() {
380 Node_List string_calls;
381 Node_List worklist;
382
383 _visited.clear();
384
385 // Prime the worklist
386 for (uint i = 1; i < C->root()->len(); i++) {
387 Node* n = C->root()->in(i);
388 if (n != NULL && !_visited.test_set(n->_idx)) {
389 worklist.push(n);
390 }
391 }
392
393 while (worklist.size() > 0) {
394 Node* ctrl = worklist.pop();
395 if (StringConcat::is_SB_toString(ctrl)) {
396 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
397 string_calls.push(csj);
398 }
399 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
400 worklist.push(ctrl->in(0));
401 }
402 if (ctrl->is_Region()) {
403 for (uint i = 1; i < ctrl->len(); i++) {
404 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
405 worklist.push(ctrl->in(i));
406 }
407 }
408 }
409 }
410 return string_calls;
411 }
412
413
build_candidate(CallStaticJavaNode * call)414 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
415 ciMethod* m = call->method();
416 ciSymbol* string_sig;
417 ciSymbol* int_sig;
418 ciSymbol* char_sig;
419 if (m->holder() == C->env()->StringBuilder_klass()) {
420 string_sig = ciSymbol::String_StringBuilder_signature();
421 int_sig = ciSymbol::int_StringBuilder_signature();
422 char_sig = ciSymbol::char_StringBuilder_signature();
423 } else if (m->holder() == C->env()->StringBuffer_klass()) {
424 string_sig = ciSymbol::String_StringBuffer_signature();
425 int_sig = ciSymbol::int_StringBuffer_signature();
426 char_sig = ciSymbol::char_StringBuffer_signature();
427 } else {
428 return NULL;
429 }
430 #ifndef PRODUCT
431 if (PrintOptimizeStringConcat) {
432 tty->print("considering toString call in ");
433 call->jvms()->dump_spec(tty); tty->cr();
434 }
435 #endif
436
437 StringConcat* sc = new StringConcat(this, call);
438
439 AllocateNode* alloc = NULL;
440 InitializeNode* init = NULL;
441
442 // possible opportunity for StringBuilder fusion
443 CallStaticJavaNode* cnode = call;
444 while (cnode) {
445 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
446 if (recv->is_Proj()) {
447 recv = recv->in(0);
448 }
449 cnode = recv->isa_CallStaticJava();
450 if (cnode == NULL) {
451 alloc = recv->isa_Allocate();
452 if (alloc == NULL) {
453 break;
454 }
455 // Find the constructor call
456 Node* result = alloc->result_cast();
457 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
458 // strange looking allocation
459 #ifndef PRODUCT
460 if (PrintOptimizeStringConcat) {
461 tty->print("giving up because allocation looks strange ");
462 alloc->jvms()->dump_spec(tty); tty->cr();
463 }
464 #endif
465 break;
466 }
467 Node* constructor = NULL;
468 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
469 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
470 if (use != NULL &&
471 use->method() != NULL &&
472 !use->method()->is_static() &&
473 use->method()->name() == ciSymbol::object_initializer_name() &&
474 use->method()->holder() == m->holder()) {
475 // Matched the constructor.
476 ciSymbol* sig = use->method()->signature()->as_symbol();
477 if (sig == ciSymbol::void_method_signature() ||
478 sig == ciSymbol::int_void_signature() ||
479 sig == ciSymbol::string_void_signature()) {
480 if (sig == ciSymbol::string_void_signature()) {
481 // StringBuilder(String) so pick this up as the first argument
482 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
483 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
484 if (type == TypePtr::NULL_PTR) {
485 // StringBuilder(null) throws exception.
486 #ifndef PRODUCT
487 if (PrintOptimizeStringConcat) {
488 tty->print("giving up because StringBuilder(null) throws exception");
489 alloc->jvms()->dump_spec(tty); tty->cr();
490 }
491 #endif
492 return NULL;
493 }
494 // StringBuilder(str) argument needs null check.
495 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
496 }
497 // The int variant takes an initial size for the backing
498 // array so just treat it like the void version.
499 constructor = use;
500 } else {
501 #ifndef PRODUCT
502 if (PrintOptimizeStringConcat) {
503 tty->print("unexpected constructor signature: %s", sig->as_utf8());
504 }
505 #endif
506 }
507 break;
508 }
509 }
510 if (constructor == NULL) {
511 // couldn't find constructor
512 #ifndef PRODUCT
513 if (PrintOptimizeStringConcat) {
514 tty->print("giving up because couldn't find constructor ");
515 alloc->jvms()->dump_spec(tty); tty->cr();
516 }
517 #endif
518 break;
519 }
520
521 // Walked all the way back and found the constructor call so see
522 // if this call converted into a direct string concatenation.
523 sc->add_control(call);
524 sc->add_control(constructor);
525 sc->add_control(alloc);
526 sc->set_allocation(alloc);
527 sc->add_constructor(constructor);
528 if (sc->validate_control_flow() && sc->validate_mem_flow()) {
529 return sc;
530 } else {
531 return NULL;
532 }
533 } else if (cnode->method() == NULL) {
534 break;
535 } else if (!cnode->method()->is_static() &&
536 cnode->method()->holder() == m->holder() &&
537 cnode->method()->name() == ciSymbol::append_name() &&
538 (cnode->method()->signature()->as_symbol() == string_sig ||
539 cnode->method()->signature()->as_symbol() == char_sig ||
540 cnode->method()->signature()->as_symbol() == int_sig)) {
541 sc->add_control(cnode);
542 Node* arg = cnode->in(TypeFunc::Parms + 1);
543 if (arg == NULL || arg->is_top()) {
544 #ifndef PRODUCT
545 if (PrintOptimizeStringConcat) {
546 tty->print("giving up because the call is effectively dead");
547 cnode->jvms()->dump_spec(tty); tty->cr();
548 }
549 #endif
550 break;
551 }
552 if (cnode->method()->signature()->as_symbol() == int_sig) {
553 sc->push_int(arg);
554 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
555 sc->push_char(arg);
556 } else {
557 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
558 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
559 if (csj->method() != NULL &&
560 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
561 arg->outcnt() == 1) {
562 // _control is the list of StringBuilder calls nodes which
563 // will be replaced by new String code after this optimization.
564 // Integer::toString() call is not part of StringBuilder calls
565 // chain. It could be eliminated only if its result is used
566 // only by this SB calls chain.
567 // Another limitation: it should be used only once because
568 // it is unknown that it is used only by this SB calls chain
569 // until all related SB calls nodes are collected.
570 assert(arg->unique_out() == cnode, "sanity");
571 sc->add_control(csj);
572 sc->push_int(csj->in(TypeFunc::Parms));
573 continue;
574 }
575 }
576 sc->push_string(arg);
577 }
578 continue;
579 } else {
580 // some unhandled signature
581 #ifndef PRODUCT
582 if (PrintOptimizeStringConcat) {
583 tty->print("giving up because encountered unexpected signature ");
584 cnode->tf()->dump(); tty->cr();
585 cnode->in(TypeFunc::Parms + 1)->dump();
586 }
587 #endif
588 break;
589 }
590 }
591 return NULL;
592 }
593
594
PhaseStringOpts(PhaseGVN * gvn,Unique_Node_List *)595 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
596 Phase(StringOpts),
597 _gvn(gvn) {
598
599 assert(OptimizeStringConcat, "shouldn't be here");
600
601 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
602 ciSymbol::make("[I"), true);
603 if (size_table_field == NULL) {
604 // Something wrong so give up.
605 assert(false, "why can't we find Integer.sizeTable?");
606 return;
607 }
608
609 // Collect the types needed to talk about the various slices of memory
610 byte_adr_idx = C->get_alias_index(TypeAryPtr::BYTES);
611
612 // For each locally allocated StringBuffer see if the usages can be
613 // collapsed into a single String construction.
614
615 // Run through the list of allocation looking for SB.toString to see
616 // if it's possible to fuse the usage of the SB into a single String
617 // construction.
618 GrowableArray<StringConcat*> concats;
619 Node_List toStrings = collect_toString_calls();
620 while (toStrings.size() > 0) {
621 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
622 if (sc != NULL) {
623 concats.push(sc);
624 }
625 }
626
627 // try to coalesce separate concats
628 restart:
629 for (int c = 0; c < concats.length(); c++) {
630 StringConcat* sc = concats.at(c);
631 for (int i = 0; i < sc->num_arguments(); i++) {
632 Node* arg = sc->argument_uncast(i);
633 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
634 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
635 for (int o = 0; o < concats.length(); o++) {
636 if (c == o) continue;
637 StringConcat* other = concats.at(o);
638 if (other->end() == csj) {
639 #ifndef PRODUCT
640 if (PrintOptimizeStringConcat) {
641 tty->print_cr("considering stacked concats");
642 }
643 #endif
644
645 StringConcat* merged = sc->merge(other, arg);
646 if (merged->validate_control_flow() && merged->validate_mem_flow()) {
647 #ifndef PRODUCT
648 if (PrintOptimizeStringConcat) {
649 tty->print_cr("stacking would succeed");
650 }
651 #endif
652 if (c < o) {
653 concats.remove_at(o);
654 concats.at_put(c, merged);
655 } else {
656 concats.remove_at(c);
657 concats.at_put(o, merged);
658 }
659 goto restart;
660 } else {
661 #ifndef PRODUCT
662 if (PrintOptimizeStringConcat) {
663 tty->print_cr("stacking would fail");
664 }
665 #endif
666 }
667 }
668 }
669 }
670 }
671 }
672
673
674 for (int c = 0; c < concats.length(); c++) {
675 StringConcat* sc = concats.at(c);
676 replace_string_concat(sc);
677 }
678
679 remove_dead_nodes();
680 }
681
record_dead_node(Node * dead)682 void PhaseStringOpts::record_dead_node(Node* dead) {
683 dead_worklist.push(dead);
684 }
685
remove_dead_nodes()686 void PhaseStringOpts::remove_dead_nodes() {
687 // Delete any dead nodes to make things clean enough that escape
688 // analysis doesn't get unhappy.
689 while (dead_worklist.size() > 0) {
690 Node* use = dead_worklist.pop();
691 int opc = use->Opcode();
692 switch (opc) {
693 case Op_Region: {
694 uint i = 1;
695 for (i = 1; i < use->req(); i++) {
696 if (use->in(i) != C->top()) {
697 break;
698 }
699 }
700 if (i >= use->req()) {
701 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
702 Node* m = i.get();
703 if (m->is_Phi()) {
704 dead_worklist.push(m);
705 }
706 }
707 C->gvn_replace_by(use, C->top());
708 }
709 break;
710 }
711 case Op_AddP:
712 case Op_CreateEx: {
713 // Recurisvely clean up references to CreateEx so EA doesn't
714 // get unhappy about the partially collapsed graph.
715 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
716 Node* m = i.get();
717 if (m->is_AddP()) {
718 dead_worklist.push(m);
719 }
720 }
721 C->gvn_replace_by(use, C->top());
722 break;
723 }
724 case Op_Phi:
725 if (use->in(0) == C->top()) {
726 C->gvn_replace_by(use, C->top());
727 }
728 break;
729 }
730 }
731 }
732
733
validate_mem_flow()734 bool StringConcat::validate_mem_flow() {
735 Compile* C = _stringopts->C;
736
737 for (uint i = 0; i < _control.size(); i++) {
738 #ifndef PRODUCT
739 Node_List path;
740 #endif
741 Node* curr = _control.at(i);
742 if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation
743 // Now here's the main invariant in our case:
744 // For memory between the constructor, and appends, and toString we should only see bottom memory,
745 // produced by the previous call we know about.
746 if (!_constructors.contains(curr)) {
747 NOT_PRODUCT(path.push(curr);)
748 Node* mem = curr->in(TypeFunc::Memory);
749 assert(mem != NULL, "calls should have memory edge");
750 assert(!mem->is_Phi(), "should be handled by control flow validation");
751 NOT_PRODUCT(path.push(mem);)
752 while (mem->is_MergeMem()) {
753 for (uint i = 1; i < mem->req(); i++) {
754 if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) {
755 #ifndef PRODUCT
756 if (PrintOptimizeStringConcat) {
757 tty->print("fusion has incorrect memory flow (side effects) for ");
758 _begin->jvms()->dump_spec(tty); tty->cr();
759 path.dump();
760 }
761 #endif
762 return false;
763 }
764 }
765 // skip through a potential MergeMem chain, linked through Bot
766 mem = mem->in(Compile::AliasIdxBot);
767 NOT_PRODUCT(path.push(mem);)
768 }
769 // now let it fall through, and see if we have a projection
770 if (mem->is_Proj()) {
771 // Should point to a previous known call
772 Node *prev = mem->in(0);
773 NOT_PRODUCT(path.push(prev);)
774 if (!prev->is_Call() || !_control.contains(prev)) {
775 #ifndef PRODUCT
776 if (PrintOptimizeStringConcat) {
777 tty->print("fusion has incorrect memory flow (unknown call) for ");
778 _begin->jvms()->dump_spec(tty); tty->cr();
779 path.dump();
780 }
781 #endif
782 return false;
783 }
784 } else {
785 assert(mem->is_Store() || mem->is_LoadStore(), "unexpected node type: %s", mem->Name());
786 #ifndef PRODUCT
787 if (PrintOptimizeStringConcat) {
788 tty->print("fusion has incorrect memory flow (unexpected source) for ");
789 _begin->jvms()->dump_spec(tty); tty->cr();
790 path.dump();
791 }
792 #endif
793 return false;
794 }
795 } else {
796 // For memory that feeds into constructors it's more complicated.
797 // However the advantage is that any side effect that happens between the Allocate/Initialize and
798 // the constructor will have to be control-dependent on Initialize.
799 // So we actually don't have to do anything, since it's going to be caught by the control flow
800 // analysis.
801 #ifdef ASSERT
802 // Do a quick verification of the control pattern between the constructor and the initialize node
803 assert(curr->is_Call(), "constructor should be a call");
804 // Go up the control starting from the constructor call
805 Node* ctrl = curr->in(0);
806 IfNode* iff = NULL;
807 RegionNode* copy = NULL;
808
809 while (true) {
810 // skip known check patterns
811 if (ctrl->is_Region()) {
812 if (ctrl->as_Region()->is_copy()) {
813 copy = ctrl->as_Region();
814 ctrl = copy->is_copy();
815 } else { // a cast
816 assert(ctrl->req() == 3 &&
817 ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() &&
818 ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() &&
819 ctrl->in(1)->in(0) == ctrl->in(2)->in(0) &&
820 ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(),
821 "must be a simple diamond");
822 Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2);
823 for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) {
824 Node* use = i.get();
825 assert(use == ctrl || use->is_ConstraintCast(),
826 "unexpected user: %s", use->Name());
827 }
828
829 iff = ctrl->in(1)->in(0)->as_If();
830 ctrl = iff->in(0);
831 }
832 } else if (ctrl->is_IfTrue()) { // null checks, class checks
833 iff = ctrl->in(0)->as_If();
834 // Verify that the other arm is an uncommon trap
835 Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
836 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
837 assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommon trap");
838 ctrl = iff->in(0);
839 } else {
840 break;
841 }
842 }
843
844 assert(ctrl->is_Proj(), "must be a projection");
845 assert(ctrl->in(0)->is_Initialize(), "should be initialize");
846 for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) {
847 Node* use = i.get();
848 assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(),
849 "unexpected user: %s", use->Name());
850 }
851 #endif // ASSERT
852 }
853 }
854 }
855
856 #ifndef PRODUCT
857 if (PrintOptimizeStringConcat) {
858 tty->print("fusion has correct memory flow for ");
859 _begin->jvms()->dump_spec(tty); tty->cr();
860 tty->cr();
861 }
862 #endif
863 return true;
864 }
865
validate_control_flow()866 bool StringConcat::validate_control_flow() {
867 // We found all the calls and arguments now lets see if it's
868 // safe to transform the graph as we would expect.
869
870 // Check to see if this resulted in too many uncommon traps previously
871 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
872 Deoptimization::Reason_intrinsic)) {
873 return false;
874 }
875
876 // Walk backwards over the control flow from toString to the
877 // allocation and make sure all the control flow is ok. This
878 // means it's either going to be eliminated once the calls are
879 // removed or it can safely be transformed into an uncommon
880 // trap.
881
882 int null_check_count = 0;
883 Unique_Node_List ctrl_path;
884
885 assert(_control.contains(_begin), "missing");
886 assert(_control.contains(_end), "missing");
887
888 // Collect the nodes that we know about and will eliminate into ctrl_path
889 for (uint i = 0; i < _control.size(); i++) {
890 // Push the call and it's control projection
891 Node* n = _control.at(i);
892 if (n->is_Allocate()) {
893 AllocateNode* an = n->as_Allocate();
894 InitializeNode* init = an->initialization();
895 ctrl_path.push(init);
896 ctrl_path.push(init->as_Multi()->proj_out(0));
897 }
898 if (n->is_Call()) {
899 CallNode* cn = n->as_Call();
900 ctrl_path.push(cn);
901 ctrl_path.push(cn->proj_out(0));
902 ctrl_path.push(cn->proj_out(0)->unique_out());
903 Node* catchproj = cn->proj_out(0)->unique_out()->as_Catch()->proj_out_or_null(0);
904 if (catchproj != NULL) {
905 ctrl_path.push(catchproj);
906 }
907 } else {
908 ShouldNotReachHere();
909 }
910 }
911
912 // Skip backwards through the control checking for unexpected control flow
913 Node* ptr = _end;
914 bool fail = false;
915 while (ptr != _begin) {
916 if (ptr->is_Call() && ctrl_path.member(ptr)) {
917 ptr = ptr->in(0);
918 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
919 ptr = ptr->in(0)->in(0)->in(0);
920 assert(ctrl_path.member(ptr), "should be a known piece of control");
921 } else if (ptr->is_IfTrue()) {
922 IfNode* iff = ptr->in(0)->as_If();
923 BoolNode* b = iff->in(1)->isa_Bool();
924
925 if (b == NULL) {
926 #ifndef PRODUCT
927 if (PrintOptimizeStringConcat) {
928 tty->print_cr("unexpected input to IfNode");
929 iff->in(1)->dump();
930 tty->cr();
931 }
932 #endif
933 fail = true;
934 break;
935 }
936
937 Node* cmp = b->in(1);
938 Node* v1 = cmp->in(1);
939 Node* v2 = cmp->in(2);
940 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
941
942 // Null check of the return of append which can simply be eliminated
943 if (b->_test._test == BoolTest::ne &&
944 v2->bottom_type() == TypePtr::NULL_PTR &&
945 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
946 // NULL check of the return value of the append
947 null_check_count++;
948 if (otherproj->outcnt() == 1) {
949 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
950 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
951 ctrl_path.push(call);
952 }
953 }
954 _control.push(ptr);
955 ptr = ptr->in(0)->in(0);
956 continue;
957 }
958
959 // A test which leads to an uncommon trap which should be safe.
960 // Later this trap will be converted into a trap that restarts
961 // at the beginning.
962 if (otherproj->outcnt() == 1) {
963 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
964 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
965 // control flow leads to uct so should be ok
966 _uncommon_traps.push(call);
967 ctrl_path.push(call);
968 ptr = ptr->in(0)->in(0);
969 continue;
970 }
971 }
972
973 #ifndef PRODUCT
974 // Some unexpected control flow we don't know how to handle.
975 if (PrintOptimizeStringConcat) {
976 tty->print_cr("failing with unknown test");
977 b->dump();
978 cmp->dump();
979 v1->dump();
980 v2->dump();
981 tty->cr();
982 }
983 #endif
984 fail = true;
985 break;
986 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
987 ptr = ptr->in(0)->in(0);
988 } else if (ptr->is_Region()) {
989 Node* copy = ptr->as_Region()->is_copy();
990 if (copy != NULL) {
991 ptr = copy;
992 continue;
993 }
994 if (ptr->req() == 3 &&
995 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
996 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
997 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
998 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
999 // Simple diamond.
1000 // XXX should check for possibly merging stores. simple data merges are ok.
1001 // The IGVN will make this simple diamond go away when it
1002 // transforms the Region. Make sure it sees it.
1003 Compile::current()->record_for_igvn(ptr);
1004 ptr = ptr->in(1)->in(0)->in(0);
1005 continue;
1006 }
1007 #ifndef PRODUCT
1008 if (PrintOptimizeStringConcat) {
1009 tty->print_cr("fusion would fail for region");
1010 _begin->dump();
1011 ptr->dump(2);
1012 }
1013 #endif
1014 fail = true;
1015 break;
1016 } else {
1017 // other unknown control
1018 if (!fail) {
1019 #ifndef PRODUCT
1020 if (PrintOptimizeStringConcat) {
1021 tty->print_cr("fusion would fail for");
1022 _begin->dump();
1023 }
1024 #endif
1025 fail = true;
1026 }
1027 #ifndef PRODUCT
1028 if (PrintOptimizeStringConcat) {
1029 ptr->dump();
1030 }
1031 #endif
1032 ptr = ptr->in(0);
1033 }
1034 }
1035 #ifndef PRODUCT
1036 if (PrintOptimizeStringConcat && fail) {
1037 tty->cr();
1038 }
1039 #endif
1040 if (fail) return !fail;
1041
1042 // Validate that all these results produced are contained within
1043 // this cluster of objects. First collect all the results produced
1044 // by calls in the region.
1045 _stringopts->_visited.clear();
1046 Node_List worklist;
1047 Node* final_result = _end->proj_out_or_null(TypeFunc::Parms);
1048 for (uint i = 0; i < _control.size(); i++) {
1049 CallNode* cnode = _control.at(i)->isa_Call();
1050 if (cnode != NULL) {
1051 _stringopts->_visited.test_set(cnode->_idx);
1052 }
1053 Node* result = cnode != NULL ? cnode->proj_out_or_null(TypeFunc::Parms) : NULL;
1054 if (result != NULL && result != final_result) {
1055 worklist.push(result);
1056 }
1057 }
1058
1059 Node* last_result = NULL;
1060 while (worklist.size() > 0) {
1061 Node* result = worklist.pop();
1062 if (_stringopts->_visited.test_set(result->_idx))
1063 continue;
1064 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
1065 Node *use = i.get();
1066 if (ctrl_path.member(use)) {
1067 // already checked this
1068 continue;
1069 }
1070 int opc = use->Opcode();
1071 if (opc == Op_CmpP || opc == Op_Node) {
1072 ctrl_path.push(use);
1073 continue;
1074 }
1075 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
1076 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
1077 worklist.push(j.get());
1078 }
1079 worklist.push(use->in(1));
1080 ctrl_path.push(use);
1081 continue;
1082 }
1083 #ifndef PRODUCT
1084 if (PrintOptimizeStringConcat) {
1085 if (result != last_result) {
1086 last_result = result;
1087 tty->print_cr("extra uses for result:");
1088 last_result->dump();
1089 }
1090 use->dump();
1091 }
1092 #endif
1093 fail = true;
1094 break;
1095 }
1096 }
1097
1098 #ifndef PRODUCT
1099 if (PrintOptimizeStringConcat && !fail) {
1100 ttyLocker ttyl;
1101 tty->cr();
1102 tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size());
1103 _begin->jvms()->dump_spec(tty); tty->cr();
1104 for (int i = 0; i < num_arguments(); i++) {
1105 argument(i)->dump();
1106 }
1107 _control.dump();
1108 tty->cr();
1109 }
1110 #endif
1111
1112 return !fail;
1113 }
1114
fetch_static_field(GraphKit & kit,ciField * field)1115 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
1116 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
1117 Node* klass_node = __ makecon(mirror_type);
1118 BasicType bt = field->layout_type();
1119 ciType* field_klass = field->type();
1120
1121 const Type *type;
1122 if( bt == T_OBJECT ) {
1123 if (!field->type()->is_loaded()) {
1124 type = TypeInstPtr::BOTTOM;
1125 } else if (field->is_static_constant()) {
1126 // This can happen if the constant oop is non-perm.
1127 ciObject* con = field->constant_value().as_object();
1128 // Do not "join" in the previous type; it doesn't add value,
1129 // and may yield a vacuous result if the field is of interface type.
1130 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
1131 assert(type != NULL, "field singleton type must be consistent");
1132 return __ makecon(type);
1133 } else {
1134 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
1135 }
1136 } else {
1137 type = Type::get_const_basic_type(bt);
1138 }
1139
1140 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
1141 type, T_OBJECT,
1142 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())),
1143 MemNode::unordered);
1144 }
1145
int_stringSize(GraphKit & kit,Node * arg)1146 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
1147 if (arg->is_Con()) {
1148 // Constant integer. Compute constant length using Integer.sizeTable
1149 int arg_val = arg->get_int();
1150 int count = 1;
1151 if (arg_val < 0) {
1152 // Special case for min_jint - it can't be negated.
1153 if (arg_val == min_jint) {
1154 return __ intcon(11);
1155 }
1156
1157 arg_val = -arg_val;
1158 count++;
1159 }
1160
1161 ciArray* size_table = (ciArray*)size_table_field->constant_value().as_object();
1162 for (int i = 0; i < size_table->length(); i++) {
1163 if (arg_val <= size_table->element_value(i).as_int()) {
1164 count += i;
1165 break;
1166 }
1167 }
1168 return __ intcon(count);
1169 }
1170
1171 RegionNode *final_merge = new RegionNode(3);
1172 kit.gvn().set_type(final_merge, Type::CONTROL);
1173 Node* final_size = new PhiNode(final_merge, TypeInt::INT);
1174 kit.gvn().set_type(final_size, TypeInt::INT);
1175
1176 IfNode* iff = kit.create_and_map_if(kit.control(),
1177 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1178 PROB_FAIR, COUNT_UNKNOWN);
1179 Node* is_min = __ IfFalse(iff);
1180 final_merge->init_req(1, is_min);
1181 final_size->init_req(1, __ intcon(11));
1182
1183 kit.set_control(__ IfTrue(iff));
1184 if (kit.stopped()) {
1185 final_merge->init_req(2, C->top());
1186 final_size->init_req(2, C->top());
1187 } else {
1188
1189 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1190 RegionNode *r = new RegionNode(3);
1191 kit.gvn().set_type(r, Type::CONTROL);
1192 Node *phi = new PhiNode(r, TypeInt::INT);
1193 kit.gvn().set_type(phi, TypeInt::INT);
1194 Node *size = new PhiNode(r, TypeInt::INT);
1195 kit.gvn().set_type(size, TypeInt::INT);
1196 Node* chk = __ CmpI(arg, __ intcon(0));
1197 Node* p = __ Bool(chk, BoolTest::lt);
1198 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1199 Node* lessthan = __ IfTrue(iff);
1200 Node* greaterequal = __ IfFalse(iff);
1201 r->init_req(1, lessthan);
1202 phi->init_req(1, __ SubI(__ intcon(0), arg));
1203 size->init_req(1, __ intcon(1));
1204 r->init_req(2, greaterequal);
1205 phi->init_req(2, arg);
1206 size->init_req(2, __ intcon(0));
1207 kit.set_control(r);
1208 C->record_for_igvn(r);
1209 C->record_for_igvn(phi);
1210 C->record_for_igvn(size);
1211
1212 // for (int i=0; ; i++)
1213 // if (x <= sizeTable[i])
1214 // return i+1;
1215
1216 // Add loop predicate first.
1217 kit.add_empty_predicates();
1218 C->set_has_loops(true);
1219
1220 RegionNode *loop = new RegionNode(3);
1221 loop->init_req(1, kit.control());
1222 kit.gvn().set_type(loop, Type::CONTROL);
1223
1224 Node *index = new PhiNode(loop, TypeInt::INT);
1225 index->init_req(1, __ intcon(0));
1226 kit.gvn().set_type(index, TypeInt::INT);
1227 kit.set_control(loop);
1228 Node* sizeTable = fetch_static_field(kit, size_table_field);
1229
1230 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1231 C->record_for_igvn(value);
1232 Node* limit = __ CmpI(phi, value);
1233 Node* limitb = __ Bool(limit, BoolTest::le);
1234 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1235 Node* lessEqual = __ IfTrue(iff2);
1236 Node* greater = __ IfFalse(iff2);
1237
1238 loop->init_req(2, greater);
1239 index->init_req(2, __ AddI(index, __ intcon(1)));
1240
1241 kit.set_control(lessEqual);
1242 C->record_for_igvn(loop);
1243 C->record_for_igvn(index);
1244
1245 final_merge->init_req(2, kit.control());
1246 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1247 }
1248
1249 kit.set_control(final_merge);
1250 C->record_for_igvn(final_merge);
1251 C->record_for_igvn(final_size);
1252
1253 return final_size;
1254 }
1255
1256 // Simplified version of Integer.getChars
getChars(GraphKit & kit,Node * arg,Node * dst_array,BasicType bt,Node * end,Node * final_merge,Node * final_mem,int merge_index)1257 void PhaseStringOpts::getChars(GraphKit& kit, Node* arg, Node* dst_array, BasicType bt, Node* end, Node* final_merge, Node* final_mem, int merge_index) {
1258 // if (i < 0) {
1259 // sign = '-';
1260 // i = -i;
1261 // }
1262 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1263 PROB_FAIR, COUNT_UNKNOWN);
1264
1265 RegionNode* merge = new RegionNode(3);
1266 kit.gvn().set_type(merge, Type::CONTROL);
1267 Node* i = new PhiNode(merge, TypeInt::INT);
1268 kit.gvn().set_type(i, TypeInt::INT);
1269 Node* sign = new PhiNode(merge, TypeInt::INT);
1270 kit.gvn().set_type(sign, TypeInt::INT);
1271
1272 merge->init_req(1, __ IfTrue(iff));
1273 i->init_req(1, __ SubI(__ intcon(0), arg));
1274 sign->init_req(1, __ intcon('-'));
1275 merge->init_req(2, __ IfFalse(iff));
1276 i->init_req(2, arg);
1277 sign->init_req(2, __ intcon(0));
1278
1279 kit.set_control(merge);
1280
1281 C->record_for_igvn(merge);
1282 C->record_for_igvn(i);
1283 C->record_for_igvn(sign);
1284
1285 // for (;;) {
1286 // q = i / 10;
1287 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1288 // buf [--charPos] = digits [r];
1289 // i = q;
1290 // if (i == 0) break;
1291 // }
1292
1293 // Add loop predicate first.
1294 kit.add_empty_predicates();
1295
1296 C->set_has_loops(true);
1297 RegionNode* head = new RegionNode(3);
1298 head->init_req(1, kit.control());
1299
1300 kit.gvn().set_type(head, Type::CONTROL);
1301 Node* i_phi = new PhiNode(head, TypeInt::INT);
1302 i_phi->init_req(1, i);
1303 kit.gvn().set_type(i_phi, TypeInt::INT);
1304 Node* charPos = new PhiNode(head, TypeInt::INT);
1305 charPos->init_req(1, end);
1306 kit.gvn().set_type(charPos, TypeInt::INT);
1307 Node* mem = PhiNode::make(head, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1308 kit.gvn().set_type(mem, Type::MEMORY);
1309
1310 kit.set_control(head);
1311 kit.set_memory(mem, byte_adr_idx);
1312
1313 Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));
1314 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1315 __ LShiftI(q, __ intcon(1))));
1316 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1317 Node* ch = __ AddI(r, __ intcon('0'));
1318 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1319 ch, bt, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1320 false /* unaligned */, (bt != T_BYTE) /* mismatched */);
1321
1322 iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1323 PROB_FAIR, COUNT_UNKNOWN);
1324 Node* ne = __ IfTrue(iff);
1325 Node* eq = __ IfFalse(iff);
1326
1327 head->init_req(2, ne);
1328 mem->init_req(2, st);
1329
1330 i_phi->init_req(2, q);
1331 charPos->init_req(2, index);
1332 charPos = index;
1333
1334 kit.set_control(eq);
1335 kit.set_memory(st, byte_adr_idx);
1336
1337 C->record_for_igvn(head);
1338 C->record_for_igvn(mem);
1339 C->record_for_igvn(i_phi);
1340 C->record_for_igvn(charPos);
1341
1342 // if (sign != 0) {
1343 // buf [--charPos] = sign;
1344 // }
1345 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1346 PROB_FAIR, COUNT_UNKNOWN);
1347
1348 final_merge->init_req(merge_index + 2, __ IfFalse(iff));
1349 final_mem->init_req(merge_index + 2, kit.memory(byte_adr_idx));
1350
1351 kit.set_control(__ IfTrue(iff));
1352 if (kit.stopped()) {
1353 final_merge->init_req(merge_index + 1, C->top());
1354 final_mem->init_req(merge_index + 1, C->top());
1355 } else {
1356 Node* index = __ SubI(charPos, __ intcon((bt == T_BYTE) ? 1 : 2));
1357 st = __ store_to_memory(kit.control(), kit.array_element_address(dst_array, index, T_BYTE),
1358 sign, bt, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1359 false /* unaligned */, (bt != T_BYTE) /* mismatched */);
1360
1361 final_merge->init_req(merge_index + 1, kit.control());
1362 final_mem->init_req(merge_index + 1, st);
1363 }
1364 }
1365
1366 // Copy the characters representing arg into dst_array starting at start
int_getChars(GraphKit & kit,Node * arg,Node * dst_array,Node * dst_coder,Node * start,Node * size)1367 Node* PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* dst_array, Node* dst_coder, Node* start, Node* size) {
1368 bool dcon = dst_coder->is_Con();
1369 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1370 Node* end = __ AddI(start, __ LShiftI(size, dst_coder));
1371
1372 // The final_merge node has 4 entries in case the encoding is known:
1373 // (0) Control, (1) result w/ sign, (2) result w/o sign, (3) result for Integer.min_value
1374 // or 6 entries in case the encoding is not known:
1375 // (0) Control, (1) Latin1 w/ sign, (2) Latin1 w/o sign, (3) min_value, (4) UTF16 w/ sign, (5) UTF16 w/o sign
1376 RegionNode* final_merge = new RegionNode(dcon ? 4 : 6);
1377 kit.gvn().set_type(final_merge, Type::CONTROL);
1378
1379 Node* final_mem = PhiNode::make(final_merge, kit.memory(byte_adr_idx), Type::MEMORY, TypeAryPtr::BYTES);
1380 kit.gvn().set_type(final_mem, Type::MEMORY);
1381
1382 // need to handle arg == Integer.MIN_VALUE specially because negating doesn't make it positive
1383 IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1384 PROB_FAIR, COUNT_UNKNOWN);
1385
1386 Node* old_mem = kit.memory(byte_adr_idx);
1387
1388 kit.set_control(__ IfFalse(iff));
1389 if (kit.stopped()) {
1390 // Statically not equal to MIN_VALUE so this path is dead
1391 final_merge->init_req(3, kit.control());
1392 } else {
1393 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1394 dst_array, dst_coder, start);
1395 final_merge->init_req(3, kit.control());
1396 final_mem->init_req(3, kit.memory(byte_adr_idx));
1397 }
1398
1399 kit.set_control(__ IfTrue(iff));
1400 kit.set_memory(old_mem, byte_adr_idx);
1401
1402 if (!dcon) {
1403 // Check encoding of destination
1404 iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(dst_coder, __ intcon(0)), BoolTest::eq),
1405 PROB_FAIR, COUNT_UNKNOWN);
1406 old_mem = kit.memory(byte_adr_idx);
1407 }
1408 if (!dcon || dbyte) {
1409 // Destination is Latin1,
1410 if (!dcon) {
1411 kit.set_control(__ IfTrue(iff));
1412 }
1413 getChars(kit, arg, dst_array, T_BYTE, end, final_merge, final_mem);
1414 }
1415 if (!dcon || !dbyte) {
1416 // Destination is UTF16
1417 int merge_index = 0;
1418 if (!dcon) {
1419 kit.set_control(__ IfFalse(iff));
1420 kit.set_memory(old_mem, byte_adr_idx);
1421 merge_index = 3; // Account for Latin1 case
1422 }
1423 getChars(kit, arg, dst_array, T_CHAR, end, final_merge, final_mem, merge_index);
1424 }
1425
1426 // Final merge point for Latin1 and UTF16 case
1427 kit.set_control(final_merge);
1428 kit.set_memory(final_mem, byte_adr_idx);
1429
1430 C->record_for_igvn(final_merge);
1431 C->record_for_igvn(final_mem);
1432 return end;
1433 }
1434
1435 // Copy 'count' bytes/chars from src_array to dst_array starting at index start
arraycopy(GraphKit & kit,IdealKit & ideal,Node * src_array,Node * dst_array,BasicType elembt,Node * start,Node * count)1436 void PhaseStringOpts::arraycopy(GraphKit& kit, IdealKit& ideal, Node* src_array, Node* dst_array, BasicType elembt, Node* start, Node* count) {
1437 assert(elembt == T_BYTE || elembt == T_CHAR, "Invalid type for arraycopy");
1438
1439 if (elembt == T_CHAR) {
1440 // Get number of chars
1441 count = __ RShiftI(count, __ intcon(1));
1442 }
1443
1444 Node* extra = NULL;
1445 #ifdef _LP64
1446 count = __ ConvI2L(count);
1447 extra = C->top();
1448 #endif
1449
1450 Node* src_ptr = __ array_element_address(src_array, __ intcon(0), T_BYTE);
1451 Node* dst_ptr = __ array_element_address(dst_array, start, T_BYTE);
1452 // Check if destination address is aligned to HeapWordSize
1453 const TypeInt* tdst = __ gvn().type(start)->is_int();
1454 bool aligned = tdst->is_con() && ((tdst->get_con() * type2aelembytes(T_BYTE)) % HeapWordSize == 0);
1455 // Figure out which arraycopy runtime method to call (disjoint, uninitialized).
1456 const char* copyfunc_name = "arraycopy";
1457 address copyfunc_addr = StubRoutines::select_arraycopy_function(elembt, aligned, true, copyfunc_name, true);
1458 ideal.make_leaf_call_no_fp(OptoRuntime::fast_arraycopy_Type(), copyfunc_addr, copyfunc_name,
1459 TypeAryPtr::BYTES, src_ptr, dst_ptr, count, extra);
1460 }
1461
1462 #undef __
1463 #define __ ideal.
1464
1465 // Copy contents of a Latin1 encoded string from src_array to dst_array
copy_latin1_string(GraphKit & kit,IdealKit & ideal,Node * src_array,IdealVariable & count,Node * dst_array,Node * dst_coder,Node * start)1466 void PhaseStringOpts::copy_latin1_string(GraphKit& kit, IdealKit& ideal, Node* src_array, IdealVariable& count,
1467 Node* dst_array, Node* dst_coder, Node* start) {
1468 bool dcon = dst_coder->is_Con();
1469 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1470
1471 if (!dcon) {
1472 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1473 }
1474 if (!dcon || dbyte) {
1475 // Destination is Latin1. Simply emit a byte arraycopy.
1476 arraycopy(kit, ideal, src_array, dst_array, T_BYTE, start, __ value(count));
1477 }
1478 if (!dcon) {
1479 __ else_();
1480 }
1481 if (!dcon || !dbyte) {
1482 // Destination is UTF16. Inflate src_array into dst_array.
1483 kit.sync_kit(ideal);
1484 if (Matcher::match_rule_supported(Op_StrInflatedCopy)) {
1485 // Use fast intrinsic
1486 Node* src = kit.array_element_address(src_array, kit.intcon(0), T_BYTE);
1487 Node* dst = kit.array_element_address(dst_array, start, T_BYTE);
1488 kit.inflate_string(src, dst, TypeAryPtr::BYTES, __ value(count));
1489 } else {
1490 // No intrinsic available, use slow method
1491 kit.inflate_string_slow(src_array, dst_array, start, __ value(count));
1492 }
1493 ideal.sync_kit(&kit);
1494 // Multiply count by two since we now need two bytes per char
1495 __ set(count, __ LShiftI(__ value(count), __ ConI(1)));
1496 }
1497 if (!dcon) {
1498 __ end_if();
1499 }
1500 }
1501
1502 // Read two bytes from index and index+1 and convert them to a char
readChar(ciTypeArray * array,int index)1503 static jchar readChar(ciTypeArray* array, int index) {
1504 int shift_high, shift_low;
1505 #ifdef VM_LITTLE_ENDIAN
1506 shift_high = 0;
1507 shift_low = 8;
1508 #else
1509 shift_high = 8;
1510 shift_low = 0;
1511 #endif
1512
1513 jchar b1 = ((jchar) array->byte_at(index)) & 0xff;
1514 jchar b2 = ((jchar) array->byte_at(index+1)) & 0xff;
1515 return (b1 << shift_high) | (b2 << shift_low);
1516 }
1517
1518 // Copy contents of constant src_array to dst_array by emitting individual stores
copy_constant_string(GraphKit & kit,IdealKit & ideal,ciTypeArray * src_array,IdealVariable & count,bool src_is_byte,Node * dst_array,Node * dst_coder,Node * start)1519 void PhaseStringOpts::copy_constant_string(GraphKit& kit, IdealKit& ideal, ciTypeArray* src_array, IdealVariable& count,
1520 bool src_is_byte, Node* dst_array, Node* dst_coder, Node* start) {
1521 bool dcon = dst_coder->is_Con();
1522 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1523 int length = src_array->length();
1524
1525 if (!dcon) {
1526 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1527 }
1528 if (!dcon || dbyte) {
1529 // Destination is Latin1. Copy each byte of src_array into dst_array.
1530 Node* index = start;
1531 for (int i = 0; i < length; i++) {
1532 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1533 Node* val = __ ConI(src_array->byte_at(i));
1534 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1535 index = __ AddI(index, __ ConI(1));
1536 }
1537 }
1538 if (!dcon) {
1539 __ else_();
1540 }
1541 if (!dcon || !dbyte) {
1542 // Destination is UTF16. Copy each char of src_array into dst_array.
1543 Node* index = start;
1544 for (int i = 0; i < length; i++) {
1545 Node* adr = kit.array_element_address(dst_array, index, T_BYTE);
1546 jchar val;
1547 if (src_is_byte) {
1548 val = src_array->byte_at(i) & 0xff;
1549 } else {
1550 val = readChar(src_array, i++);
1551 }
1552 __ store(__ ctrl(), adr, __ ConI(val), T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1553 true /* mismatched */);
1554 index = __ AddI(index, __ ConI(2));
1555 }
1556 if (src_is_byte) {
1557 // Multiply count by two since we now need two bytes per char
1558 __ set(count, __ ConI(2 * length));
1559 }
1560 }
1561 if (!dcon) {
1562 __ end_if();
1563 }
1564 }
1565
1566 // Compress copy contents of the byte/char String str into dst_array starting at index start.
copy_string(GraphKit & kit,Node * str,Node * dst_array,Node * dst_coder,Node * start)1567 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* dst_array, Node* dst_coder, Node* start) {
1568 Node* src_array = kit.load_String_value(str, true);
1569
1570 IdealKit ideal(&kit, true, true);
1571 IdealVariable count(ideal); __ declarations_done();
1572
1573 if (str->is_Con()) {
1574 // Constant source string
1575 ciTypeArray* src_array_type = get_constant_value(kit, str);
1576
1577 // Check encoding of constant string
1578 bool src_is_byte = (get_constant_coder(kit, str) == java_lang_String::CODER_LATIN1);
1579
1580 // For small constant strings just emit individual stores.
1581 // A length of 6 seems like a good space/speed tradeof.
1582 __ set(count, __ ConI(src_array_type->length()));
1583 int src_len = src_array_type->length() / (src_is_byte ? 1 : 2);
1584 if (src_len < unroll_string_copy_length) {
1585 // Small constant string
1586 copy_constant_string(kit, ideal, src_array_type, count, src_is_byte, dst_array, dst_coder, start);
1587 } else if (src_is_byte) {
1588 // Source is Latin1
1589 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1590 } else {
1591 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1592 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1593 }
1594 } else {
1595 Node* size = kit.load_array_length(src_array);
1596 __ set(count, size);
1597 // Non-constant source string
1598 if (CompactStrings) {
1599 // Emit runtime check for coder
1600 Node* coder = kit.load_String_coder(str, true);
1601 __ if_then(coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1)); {
1602 // Source is Latin1
1603 copy_latin1_string(kit, ideal, src_array, count, dst_array, dst_coder, start);
1604 } __ else_();
1605 }
1606 // Source is UTF16 (destination too). Simply emit a char arraycopy.
1607 arraycopy(kit, ideal, src_array, dst_array, T_CHAR, start, __ value(count));
1608
1609 if (CompactStrings) {
1610 __ end_if();
1611 }
1612 }
1613
1614 // Finally sync IdealKit and GraphKit.
1615 kit.sync_kit(ideal);
1616 return __ AddI(start, __ value(count));
1617 }
1618
1619 // Compress copy the char into dst_array at index start.
copy_char(GraphKit & kit,Node * val,Node * dst_array,Node * dst_coder,Node * start)1620 Node* PhaseStringOpts::copy_char(GraphKit& kit, Node* val, Node* dst_array, Node* dst_coder, Node* start) {
1621 bool dcon = (dst_coder != NULL) && dst_coder->is_Con();
1622 bool dbyte = dcon ? (dst_coder->get_int() == java_lang_String::CODER_LATIN1) : false;
1623
1624 IdealKit ideal(&kit, true, true);
1625 IdealVariable end(ideal); __ declarations_done();
1626 Node* adr = kit.array_element_address(dst_array, start, T_BYTE);
1627 if (!dcon){
1628 __ if_then(dst_coder, BoolTest::eq, __ ConI(java_lang_String::CODER_LATIN1));
1629 }
1630 if (!dcon || dbyte) {
1631 // Destination is Latin1. Store a byte.
1632 __ store(__ ctrl(), adr, val, T_BYTE, byte_adr_idx, MemNode::unordered);
1633 __ set(end, __ AddI(start, __ ConI(1)));
1634 }
1635 if (!dcon) {
1636 __ else_();
1637 }
1638 if (!dcon || !dbyte) {
1639 // Destination is UTF16. Store a char.
1640 __ store(__ ctrl(), adr, val, T_CHAR, byte_adr_idx, MemNode::unordered, false /* require_atomic_access */,
1641 true /* mismatched */);
1642 __ set(end, __ AddI(start, __ ConI(2)));
1643 }
1644 if (!dcon) {
1645 __ end_if();
1646 }
1647 // Finally sync IdealKit and GraphKit.
1648 kit.sync_kit(ideal);
1649 return __ value(end);
1650 }
1651
1652 #undef __
1653 #define __ kit.
1654
1655 // Allocate a byte array of specified length.
allocate_byte_array(GraphKit & kit,IdealKit * ideal,Node * length)1656 Node* PhaseStringOpts::allocate_byte_array(GraphKit& kit, IdealKit* ideal, Node* length) {
1657 if (ideal != NULL) {
1658 // Sync IdealKit and graphKit.
1659 kit.sync_kit(*ideal);
1660 }
1661 Node* byte_array = NULL;
1662 {
1663 PreserveReexecuteState preexecs(&kit);
1664 // The original jvms is for an allocation of either a String or
1665 // StringBuffer so no stack adjustment is necessary for proper
1666 // reexecution. If we deoptimize in the slow path the bytecode
1667 // will be reexecuted and the char[] allocation will be thrown away.
1668 kit.jvms()->set_should_reexecute(true);
1669 byte_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_BYTE))),
1670 length, 1);
1671 }
1672
1673 // Mark the allocation so that zeroing is skipped since the code
1674 // below will overwrite the entire array
1675 AllocateArrayNode* byte_alloc = AllocateArrayNode::Ideal_array_allocation(byte_array, _gvn);
1676 byte_alloc->maybe_set_complete(_gvn);
1677
1678 if (ideal != NULL) {
1679 // Sync IdealKit and graphKit.
1680 ideal->sync_kit(&kit);
1681 }
1682 return byte_array;
1683 }
1684
get_constant_coder(GraphKit & kit,Node * str)1685 jbyte PhaseStringOpts::get_constant_coder(GraphKit& kit, Node* str) {
1686 assert(str->is_Con(), "String must be constant");
1687 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1688 ciInstance* str_instance = str_type->const_oop()->as_instance();
1689 jbyte coder = str_instance->field_value_by_offset(java_lang_String::coder_offset()).as_byte();
1690 assert(CompactStrings || (coder == java_lang_String::CODER_UTF16), "Strings must be UTF16 encoded");
1691 return coder;
1692 }
1693
get_constant_length(GraphKit & kit,Node * str)1694 int PhaseStringOpts::get_constant_length(GraphKit& kit, Node* str) {
1695 assert(str->is_Con(), "String must be constant");
1696 return get_constant_value(kit, str)->length();
1697 }
1698
get_constant_value(GraphKit & kit,Node * str)1699 ciTypeArray* PhaseStringOpts::get_constant_value(GraphKit& kit, Node* str) {
1700 assert(str->is_Con(), "String must be constant");
1701 const TypeOopPtr* str_type = kit.gvn().type(str)->isa_oopptr();
1702 ciInstance* str_instance = str_type->const_oop()->as_instance();
1703 ciObject* src_array = str_instance->field_value_by_offset(java_lang_String::value_offset()).as_object();
1704 return src_array->as_type_array();
1705 }
1706
replace_string_concat(StringConcat * sc)1707 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1708 // Log a little info about the transformation
1709 sc->maybe_log_transform();
1710
1711 // pull the JVMState of the allocation into a SafePointNode to serve as
1712 // as a shim for the insertion of the new code.
1713 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1714 uint size = sc->begin()->req();
1715 SafePointNode* map = new SafePointNode(size, jvms);
1716
1717 // copy the control and memory state from the final call into our
1718 // new starting state. This allows any preceeding tests to feed
1719 // into the new section of code.
1720 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1721 map->init_req(i1, sc->end()->in(i1));
1722 }
1723 // blow away old allocation arguments
1724 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1725 map->init_req(i1, C->top());
1726 }
1727 // Copy the rest of the inputs for the JVMState
1728 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1729 map->init_req(i1, sc->begin()->in(i1));
1730 }
1731 // Make sure the memory state is a MergeMem for parsing.
1732 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1733 map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory)));
1734 }
1735
1736 jvms->set_map(map);
1737 map->ensure_stack(jvms, jvms->method()->max_stack());
1738
1739 // disconnect all the old StringBuilder calls from the graph
1740 sc->eliminate_unneeded_control();
1741
1742 // At this point all the old work has been completely removed from
1743 // the graph and the saved JVMState exists at the point where the
1744 // final toString call used to be.
1745 GraphKit kit(jvms);
1746
1747 // There may be uncommon traps which are still using the
1748 // intermediate states and these need to be rewritten to point at
1749 // the JVMState at the beginning of the transformation.
1750 sc->convert_uncommon_traps(kit, jvms);
1751
1752 // Now insert the logic to compute the size of the string followed
1753 // by all the logic to construct array and resulting string.
1754
1755 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1756
1757 // Create a region for the overflow checks to merge into.
1758 int args = MAX2(sc->num_arguments(), 1);
1759 RegionNode* overflow = new RegionNode(args);
1760 kit.gvn().set_type(overflow, Type::CONTROL);
1761
1762 // Create a hook node to hold onto the individual sizes since they
1763 // are need for the copying phase.
1764 Node* string_sizes = new Node(args);
1765
1766 Node* coder = __ intcon(0);
1767 Node* length = __ intcon(0);
1768 // If at least one argument is UTF16 encoded, we can fix the encoding.
1769 bool coder_fixed = false;
1770
1771 if (!CompactStrings) {
1772 // Fix encoding of result string to UTF16
1773 coder_fixed = true;
1774 coder = __ intcon(java_lang_String::CODER_UTF16);
1775 }
1776
1777 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1778 Node* arg = sc->argument(argi);
1779 switch (sc->mode(argi)) {
1780 case StringConcat::IntMode: {
1781 Node* string_size = int_stringSize(kit, arg);
1782
1783 // accumulate total
1784 length = __ AddI(length, string_size);
1785
1786 // Cache this value for the use by int_toString
1787 string_sizes->init_req(argi, string_size);
1788 break;
1789 }
1790 case StringConcat::StringNullCheckMode: {
1791 const Type* type = kit.gvn().type(arg);
1792 assert(type != TypePtr::NULL_PTR, "missing check");
1793 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1794 // Null check with uncommon trap since
1795 // StringBuilder(null) throws exception.
1796 // Use special uncommon trap instead of
1797 // calling normal do_null_check().
1798 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1799 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1800 overflow->add_req(__ IfFalse(iff));
1801 Node* notnull = __ IfTrue(iff);
1802 kit.set_control(notnull); // set control for the cast_not_null
1803 arg = kit.cast_not_null(arg, false);
1804 sc->set_argument(argi, arg);
1805 }
1806 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1807 // Fallthrough to add string length.
1808 }
1809 case StringConcat::StringMode: {
1810 const Type* type = kit.gvn().type(arg);
1811 Node* count = NULL;
1812 Node* arg_coder = NULL;
1813 if (type == TypePtr::NULL_PTR) {
1814 // replace the argument with the null checked version
1815 arg = null_string;
1816 sc->set_argument(argi, arg);
1817 count = kit.load_String_length(arg, true);
1818 arg_coder = kit.load_String_coder(arg, true);
1819 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1820 // s = s != null ? s : "null";
1821 // length = length + (s.count - s.offset);
1822 RegionNode *r = new RegionNode(3);
1823 kit.gvn().set_type(r, Type::CONTROL);
1824 Node *phi = new PhiNode(r, type);
1825 kit.gvn().set_type(phi, phi->bottom_type());
1826 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1827 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1828 Node* notnull = __ IfTrue(iff);
1829 Node* isnull = __ IfFalse(iff);
1830 kit.set_control(notnull); // set control for the cast_not_null
1831 r->init_req(1, notnull);
1832 phi->init_req(1, kit.cast_not_null(arg, false));
1833 r->init_req(2, isnull);
1834 phi->init_req(2, null_string);
1835 kit.set_control(r);
1836 C->record_for_igvn(r);
1837 C->record_for_igvn(phi);
1838 // replace the argument with the null checked version
1839 arg = phi;
1840 sc->set_argument(argi, arg);
1841 count = kit.load_String_length(arg, true);
1842 arg_coder = kit.load_String_coder(arg, true);
1843 } else {
1844 // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP
1845 // kit.control might be a different test, that can be hoisted above the actual nullcheck
1846 // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck.
1847 count = kit.load_String_length(arg, false);
1848 arg_coder = kit.load_String_coder(arg, false);
1849 }
1850 if (arg->is_Con()) {
1851 // Constant string. Get constant coder and length.
1852 jbyte const_coder = get_constant_coder(kit, arg);
1853 int const_length = get_constant_length(kit, arg);
1854 if (const_coder == java_lang_String::CODER_LATIN1) {
1855 // Can be latin1 encoded
1856 arg_coder = __ intcon(const_coder);
1857 count = __ intcon(const_length);
1858 } else {
1859 // Found UTF16 encoded string. Fix result array encoding to UTF16.
1860 coder_fixed = true;
1861 coder = __ intcon(const_coder);
1862 count = __ intcon(const_length / 2);
1863 }
1864 }
1865
1866 if (!coder_fixed) {
1867 coder = __ OrI(coder, arg_coder);
1868 }
1869 length = __ AddI(length, count);
1870 string_sizes->init_req(argi, NULL);
1871 break;
1872 }
1873 case StringConcat::CharMode: {
1874 // one character only
1875 const TypeInt* t = kit.gvn().type(arg)->is_int();
1876 if (!coder_fixed && t->is_con()) {
1877 // Constant char
1878 if (t->get_con() <= 255) {
1879 // Can be latin1 encoded
1880 coder = __ OrI(coder, __ intcon(java_lang_String::CODER_LATIN1));
1881 } else {
1882 // Must be UTF16 encoded. Fix result array encoding to UTF16.
1883 coder_fixed = true;
1884 coder = __ intcon(java_lang_String::CODER_UTF16);
1885 }
1886 } else if (!coder_fixed) {
1887 // Not constant
1888 #undef __
1889 #define __ ideal.
1890 IdealKit ideal(&kit, true, true);
1891 IdealVariable char_coder(ideal); __ declarations_done();
1892 // Check if character can be latin1 encoded
1893 __ if_then(arg, BoolTest::le, __ ConI(0xFF));
1894 __ set(char_coder, __ ConI(java_lang_String::CODER_LATIN1));
1895 __ else_();
1896 __ set(char_coder, __ ConI(java_lang_String::CODER_UTF16));
1897 __ end_if();
1898 kit.sync_kit(ideal);
1899 coder = __ OrI(coder, __ value(char_coder));
1900 #undef __
1901 #define __ kit.
1902 }
1903 length = __ AddI(length, __ intcon(1));
1904 break;
1905 }
1906 default:
1907 ShouldNotReachHere();
1908 }
1909 if (argi > 0) {
1910 // Check that the sum hasn't overflowed
1911 IfNode* iff = kit.create_and_map_if(kit.control(),
1912 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1913 PROB_MIN, COUNT_UNKNOWN);
1914 kit.set_control(__ IfFalse(iff));
1915 overflow->set_req(argi, __ IfTrue(iff));
1916 }
1917 }
1918
1919 {
1920 // Hook
1921 PreserveJVMState pjvms(&kit);
1922 kit.set_control(overflow);
1923 C->record_for_igvn(overflow);
1924 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1925 Deoptimization::Action_make_not_entrant);
1926 }
1927
1928 Node* result;
1929 if (!kit.stopped()) {
1930 assert(CompactStrings || (coder->is_Con() && coder->get_int() == java_lang_String::CODER_UTF16),
1931 "Result string must be UTF16 encoded if CompactStrings is disabled");
1932
1933 Node* dst_array = NULL;
1934 if (sc->num_arguments() == 1 &&
1935 (sc->mode(0) == StringConcat::StringMode ||
1936 sc->mode(0) == StringConcat::StringNullCheckMode)) {
1937 // Handle the case when there is only a single String argument.
1938 // In this case, we can just pull the value from the String itself.
1939 dst_array = kit.load_String_value(sc->argument(0), true);
1940 } else {
1941 // Allocate destination byte array according to coder
1942 dst_array = allocate_byte_array(kit, NULL, __ LShiftI(length, coder));
1943
1944 // Now copy the string representations into the final byte[]
1945 Node* start = __ intcon(0);
1946 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1947 Node* arg = sc->argument(argi);
1948 switch (sc->mode(argi)) {
1949 case StringConcat::IntMode: {
1950 start = int_getChars(kit, arg, dst_array, coder, start, string_sizes->in(argi));
1951 break;
1952 }
1953 case StringConcat::StringNullCheckMode:
1954 case StringConcat::StringMode: {
1955 start = copy_string(kit, arg, dst_array, coder, start);
1956 break;
1957 }
1958 case StringConcat::CharMode: {
1959 start = copy_char(kit, arg, dst_array, coder, start);
1960 break;
1961 }
1962 default:
1963 ShouldNotReachHere();
1964 }
1965 }
1966 }
1967
1968 // If we're not reusing an existing String allocation then allocate one here.
1969 result = sc->string_alloc();
1970 if (result == NULL) {
1971 PreserveReexecuteState preexecs(&kit);
1972 // The original jvms is for an allocation of either a String or
1973 // StringBuffer so no stack adjustment is necessary for proper
1974 // reexecution.
1975 kit.jvms()->set_should_reexecute(true);
1976 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1977 }
1978
1979 // Initialize the string
1980 kit.store_String_value(result, dst_array);
1981 kit.store_String_coder(result, coder);
1982
1983 // The value field is final. Emit a barrier here to ensure that the effect
1984 // of the initialization is committed to memory before any code publishes
1985 // a reference to the newly constructed object (see Parse::do_exits()).
1986 assert(AllocateNode::Ideal_allocation(result, _gvn) != NULL, "should be newly allocated");
1987 kit.insert_mem_bar(Op_MemBarRelease, result);
1988 } else {
1989 result = C->top();
1990 }
1991 // hook up the outgoing control and result
1992 kit.replace_call(sc->end(), result);
1993
1994 // Unhook any hook nodes
1995 string_sizes->disconnect_inputs(C);
1996 sc->cleanup();
1997 }
1998