1 /*
   2  * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "opto/addnode.hpp"
  28 #include "opto/callGenerator.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/divnode.hpp"
  31 #include "opto/graphKit.hpp"
  32 #include "opto/idealKit.hpp"
  33 #include "opto/rootnode.hpp"
  34 #include "opto/runtime.hpp"
  35 #include "opto/stringopts.hpp"
  36 #include "opto/subnode.hpp"
  37 
  38 #define __ kit.
  39 
  40 class StringConcat : public ResourceObj {
  41  private:
  42   PhaseStringOpts*    _stringopts;
  43   Node*               _string_alloc;
  44   AllocateNode*       _begin;          // The allocation the begins the pattern

  45   CallStaticJavaNode* _end;            // The final call of the pattern.  Will either be
  46                                        // SB.toString or or String.<init>(SB.toString)
  47   bool                _multiple;       // indicates this is a fusion of two or more
  48                                        // separate StringBuilders
  49 
  50   Node*               _arguments;      // The list of arguments to be concatenated
  51   GrowableArray<int>  _mode;           // into a String along with a mode flag
  52                                        // indicating how to treat the value.
  53 
  54   Node_List           _control;        // List of control nodes that will be deleted
  55   Node_List           _uncommon_traps; // Uncommon traps that needs to be rewritten
  56                                        // to restart at the initial JVMState.

  57  public:
  58   // Mode for converting arguments to Strings
  59   enum {
  60     StringMode,
  61     IntMode,
  62     CharMode,
  63     StringNullCheckMode
  64   };
  65 
  66   StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
  67     _end(end),
  68     _begin(NULL),
  69     _multiple(false),
  70     _string_alloc(NULL),
  71     _stringopts(stringopts) {
  72     _arguments = new (_stringopts->C) Node(1);
  73     _arguments->del_req(0);
  74   }
  75 

  76   bool validate_control_flow();
  77 
  78   void merge_add() {
  79 #if 0
  80     // XXX This is place holder code for reusing an existing String
  81     // allocation but the logic for checking the state safety is
  82     // probably inadequate at the moment.
  83     CallProjections endprojs;
  84     sc->end()->extract_projections(&endprojs, false);
  85     if (endprojs.resproj != NULL) {
  86       for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
  87         CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
  88         if (use != NULL && use->method() != NULL &&
  89             use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
  90             use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
  91           // Found useless new String(sb.toString()) so reuse the newly allocated String
  92           // when creating the result instead of allocating a new one.
  93           sc->set_string_alloc(use->in(TypeFunc::Parms));
  94           sc->set_end(use);
  95         }
  96       }
  97     }
  98 #endif
  99   }
 100 
 101   StringConcat* merge(StringConcat* other, Node* arg);
 102 
 103   void set_allocation(AllocateNode* alloc) {
 104     _begin = alloc;
 105   }
 106 


 107   void append(Node* value, int mode) {
 108     _arguments->add_req(value);
 109     _mode.append(mode);
 110   }
 111   void push(Node* value, int mode) {
 112     _arguments->ins_req(0, value);
 113     _mode.insert_before(0, mode);
 114   }
 115 
 116   void push_string(Node* value) {
 117     push(value, StringMode);
 118   }
 119   void push_string_null_check(Node* value) {
 120     push(value, StringNullCheckMode);
 121   }
 122   void push_int(Node* value) {
 123     push(value, IntMode);
 124   }
 125   void push_char(Node* value) {
 126     push(value, CharMode);
 127   }
 128 
 129   static bool is_SB_toString(Node* call) {
 130     if (call->is_CallStaticJava()) {
 131       CallStaticJavaNode* csj = call->as_CallStaticJava();
 132       ciMethod* m = csj->method();
 133       if (m != NULL &&
 134           (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
 135            m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
 136         return true;
 137       }
 138     }
 139     return false;
 140   }
 141 
 142   static Node* skip_string_null_check(Node* value) {
 143     // Look for a diamond shaped Null check of toString() result
 144     // (could be code from String.valueOf()):
 145     // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
 146     if (value->is_Phi()) {
 147       int true_path = value->as_Phi()->is_diamond_phi();
 148       if (true_path != 0) {
 149         // phi->region->if_proj->ifnode->bool
 150         BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
 151         Node* cmp = b->in(1);
 152         Node* v1 = cmp->in(1);
 153         Node* v2 = cmp->in(2);
 154         // Null check of the return of toString which can simply be skipped.
 155         if (b->_test._test == BoolTest::ne &&
 156             v2->bottom_type() == TypePtr::NULL_PTR &&
 157             value->in(true_path)->Opcode() == Op_CastPP &&
 158             value->in(true_path)->in(1) == v1 &&
 159             v1->is_Proj() && is_SB_toString(v1->in(0))) {
 160           return v1;
 161         }
 162       }
 163     }
 164     return value;
 165   }
 166 
 167   Node* argument(int i) {
 168     return _arguments->in(i);
 169   }
 170   Node* argument_uncast(int i) {
 171     Node* arg = argument(i);
 172     int amode = mode(i);
 173     if (amode == StringConcat::StringMode ||
 174         amode == StringConcat::StringNullCheckMode) {
 175       arg = skip_string_null_check(arg);
 176     }
 177     return arg;
 178   }
 179   void set_argument(int i, Node* value) {
 180     _arguments->set_req(i, value);
 181   }
 182   int num_arguments() {
 183     return _mode.length();
 184   }
 185   int mode(int i) {
 186     return _mode.at(i);
 187   }
 188   void add_control(Node* ctrl) {
 189     assert(!_control.contains(ctrl), "only push once");
 190     _control.push(ctrl);
 191   }
 192   CallStaticJavaNode* end() { return _end; }
 193   AllocateNode* begin() { return _begin; }
 194   Node* string_alloc() { return _string_alloc; }
 195 
 196   void eliminate_unneeded_control();
 197   void eliminate_initialize(InitializeNode* init);
 198   void eliminate_call(CallNode* call);
 199 
 200   void maybe_log_transform() {
 201     CompileLog* log = _stringopts->C->log();
 202     if (log != NULL) {
 203       log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
 204                 num_arguments(),
 205                 _string_alloc != NULL,
 206                 _multiple);
 207       JVMState* p = _begin->jvms();
 208       while (p != NULL) {
 209         log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
 210         p = p->caller();
 211       }
 212       log->tail("replace_string_concat");
 213     }
 214   }
 215 
 216   void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
 217     for (uint u = 0; u < _uncommon_traps.size(); u++) {
 218       Node* uct = _uncommon_traps.at(u);
 219 
 220       // Build a new call using the jvms state of the allocate
 221       address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
 222       const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
 223       const TypePtr* no_memory_effects = NULL;
 224       Compile* C = _stringopts->C;
 225       CallStaticJavaNode* call = new (C) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
 226                                                             jvms->bci(), no_memory_effects);
 227       for (int e = 0; e < TypeFunc::Parms; e++) {
 228         call->init_req(e, uct->in(e));
 229       }
 230       // Set the trap request to record intrinsic failure if this trap
 231       // is taken too many times.  Ideally we would handle then traps by
 232       // doing the original bookkeeping in the MDO so that if it caused
 233       // the code to be thrown out we could still recompile and use the
 234       // optimization.  Failing the uncommon traps doesn't really mean
 235       // that the optimization is a bad idea but there's no other way to
 236       // do the MDO updates currently.
 237       int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
 238                                                            Deoptimization::Action_make_not_entrant);
 239       call->init_req(TypeFunc::Parms, __ intcon(trap_request));
 240       kit.add_safepoint_edges(call);
 241 
 242       _stringopts->gvn()->transform(call);
 243       C->gvn_replace_by(uct, call);
 244       uct->disconnect_inputs(NULL, C);
 245     }
 246   }
 247 
 248   void cleanup() {
 249     // disconnect the hook node
 250     _arguments->disconnect_inputs(NULL, _stringopts->C);
 251   }
 252 };
 253 
 254 
 255 void StringConcat::eliminate_unneeded_control() {
 256   for (uint i = 0; i < _control.size(); i++) {
 257     Node* n = _control.at(i);
 258     if (n->is_Allocate()) {
 259       eliminate_initialize(n->as_Allocate()->initialization());
 260     }
 261     if (n->is_Call()) {
 262       if (n != _end) {
 263         eliminate_call(n->as_Call());
 264       }
 265     } else if (n->is_IfTrue()) {
 266       Compile* C = _stringopts->C;
 267       C->gvn_replace_by(n, n->in(0)->in(0));
 268       // get rid of the other projection
 269       C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
 270     }
 271   }
 272 }
 273 
 274 
 275 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
 276   StringConcat* result = new StringConcat(_stringopts, _end);
 277   for (uint x = 0; x < _control.size(); x++) {
 278     Node* n = _control.at(x);
 279     if (n->is_Call()) {
 280       result->_control.push(n);
 281     }
 282   }
 283   for (uint x = 0; x < other->_control.size(); x++) {
 284     Node* n = other->_control.at(x);
 285     if (n->is_Call()) {
 286       result->_control.push(n);
 287     }
 288   }
 289   assert(result->_control.contains(other->_end), "what?");
 290   assert(result->_control.contains(_begin), "what?");
 291   for (int x = 0; x < num_arguments(); x++) {
 292     Node* argx = argument_uncast(x);
 293     if (argx == arg) {
 294       // replace the toString result with the all the arguments that
 295       // made up the other StringConcat
 296       for (int y = 0; y < other->num_arguments(); y++) {
 297         result->append(other->argument(y), other->mode(y));
 298       }
 299     } else {
 300       result->append(argx, mode(x));
 301     }
 302   }
 303   result->set_allocation(other->_begin);
 304   result->_multiple = true;
 305   return result;
 306 }
 307 
 308 
 309 void StringConcat::eliminate_call(CallNode* call) {
 310   Compile* C = _stringopts->C;
 311   CallProjections projs;
 312   call->extract_projections(&projs, false);
 313   if (projs.fallthrough_catchproj != NULL) {
 314     C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
 315   }
 316   if (projs.fallthrough_memproj != NULL) {
 317     C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
 318   }
 319   if (projs.catchall_memproj != NULL) {
 320     C->gvn_replace_by(projs.catchall_memproj, C->top());
 321   }
 322   if (projs.fallthrough_ioproj != NULL) {
 323     C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
 324   }
 325   if (projs.catchall_ioproj != NULL) {
 326     C->gvn_replace_by(projs.catchall_ioproj, C->top());
 327   }
 328   if (projs.catchall_catchproj != NULL) {
 329     // EA can't cope with the partially collapsed graph this
 330     // creates so put it on the worklist to be collapsed later.
 331     for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
 332       Node *use = i.get();
 333       int opc = use->Opcode();
 334       if (opc == Op_CreateEx || opc == Op_Region) {
 335         _stringopts->record_dead_node(use);
 336       }
 337     }
 338     C->gvn_replace_by(projs.catchall_catchproj, C->top());
 339   }
 340   if (projs.resproj != NULL) {
 341     C->gvn_replace_by(projs.resproj, C->top());
 342   }
 343   C->gvn_replace_by(call, C->top());
 344 }
 345 
 346 void StringConcat::eliminate_initialize(InitializeNode* init) {
 347   Compile* C = _stringopts->C;
 348 
 349   // Eliminate Initialize node.
 350   assert(init->outcnt() <= 2, "only a control and memory projection expected");
 351   assert(init->req() <= InitializeNode::RawStores, "no pending inits");
 352   Node *ctrl_proj = init->proj_out(TypeFunc::Control);
 353   if (ctrl_proj != NULL) {
 354     C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
 355   }
 356   Node *mem_proj = init->proj_out(TypeFunc::Memory);
 357   if (mem_proj != NULL) {
 358     Node *mem = init->in(TypeFunc::Memory);
 359     C->gvn_replace_by(mem_proj, mem);
 360   }
 361   C->gvn_replace_by(init, C->top());
 362   init->disconnect_inputs(NULL, C);
 363 }
 364 
 365 Node_List PhaseStringOpts::collect_toString_calls() {
 366   Node_List string_calls;
 367   Node_List worklist;
 368 
 369   _visited.Clear();
 370 
 371   // Prime the worklist
 372   for (uint i = 1; i < C->root()->len(); i++) {
 373     Node* n = C->root()->in(i);
 374     if (n != NULL && !_visited.test_set(n->_idx)) {
 375       worklist.push(n);
 376     }
 377   }
 378 
 379   while (worklist.size() > 0) {
 380     Node* ctrl = worklist.pop();
 381     if (StringConcat::is_SB_toString(ctrl)) {
 382       CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
 383       string_calls.push(csj);
 384     }
 385     if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
 386       worklist.push(ctrl->in(0));
 387     }
 388     if (ctrl->is_Region()) {
 389       for (uint i = 1; i < ctrl->len(); i++) {
 390         if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
 391           worklist.push(ctrl->in(i));
 392         }
 393       }
 394     }
 395   }
 396   return string_calls;
 397 }
 398 
 399 
 400 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
 401   ciMethod* m = call->method();
 402   ciSymbol* string_sig;
 403   ciSymbol* int_sig;
 404   ciSymbol* char_sig;
 405   if (m->holder() == C->env()->StringBuilder_klass()) {
 406     string_sig = ciSymbol::String_StringBuilder_signature();
 407     int_sig = ciSymbol::int_StringBuilder_signature();
 408     char_sig = ciSymbol::char_StringBuilder_signature();
 409   } else if (m->holder() == C->env()->StringBuffer_klass()) {
 410     string_sig = ciSymbol::String_StringBuffer_signature();
 411     int_sig = ciSymbol::int_StringBuffer_signature();
 412     char_sig = ciSymbol::char_StringBuffer_signature();
 413   } else {
 414     return NULL;
 415   }
 416 #ifndef PRODUCT
 417   if (PrintOptimizeStringConcat) {
 418     tty->print("considering toString call in ");
 419     call->jvms()->dump_spec(tty); tty->cr();
 420   }
 421 #endif
 422 
 423   StringConcat* sc = new StringConcat(this, call);
 424 
 425   AllocateNode* alloc = NULL;
 426   InitializeNode* init = NULL;
 427 
 428   // possible opportunity for StringBuilder fusion
 429   CallStaticJavaNode* cnode = call;
 430   while (cnode) {
 431     Node* recv = cnode->in(TypeFunc::Parms)->uncast();
 432     if (recv->is_Proj()) {
 433       recv = recv->in(0);
 434     }
 435     cnode = recv->isa_CallStaticJava();
 436     if (cnode == NULL) {
 437       alloc = recv->isa_Allocate();
 438       if (alloc == NULL) {
 439         break;
 440       }
 441       // Find the constructor call
 442       Node* result = alloc->result_cast();
 443       if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
 444         // strange looking allocation
 445 #ifndef PRODUCT
 446         if (PrintOptimizeStringConcat) {
 447           tty->print("giving up because allocation looks strange ");
 448           alloc->jvms()->dump_spec(tty); tty->cr();
 449         }
 450 #endif
 451         break;
 452       }
 453       Node* constructor = NULL;
 454       for (SimpleDUIterator i(result); i.has_next(); i.next()) {
 455         CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
 456         if (use != NULL &&
 457             use->method() != NULL &&
 458             !use->method()->is_static() &&
 459             use->method()->name() == ciSymbol::object_initializer_name() &&
 460             use->method()->holder() == m->holder()) {
 461           // Matched the constructor.
 462           ciSymbol* sig = use->method()->signature()->as_symbol();
 463           if (sig == ciSymbol::void_method_signature() ||
 464               sig == ciSymbol::int_void_signature() ||
 465               sig == ciSymbol::string_void_signature()) {
 466             if (sig == ciSymbol::string_void_signature()) {
 467               // StringBuilder(String) so pick this up as the first argument
 468               assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
 469               const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
 470               if (type == TypePtr::NULL_PTR) {
 471                 // StringBuilder(null) throws exception.
 472 #ifndef PRODUCT
 473                 if (PrintOptimizeStringConcat) {
 474                   tty->print("giving up because StringBuilder(null) throws exception");
 475                   alloc->jvms()->dump_spec(tty); tty->cr();
 476                 }
 477 #endif
 478                 return NULL;
 479               }
 480               // StringBuilder(str) argument needs null check.
 481               sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
 482             }
 483             // The int variant takes an initial size for the backing
 484             // array so just treat it like the void version.
 485             constructor = use;
 486           } else {
 487 #ifndef PRODUCT
 488             if (PrintOptimizeStringConcat) {
 489               tty->print("unexpected constructor signature: %s", sig->as_utf8());
 490             }
 491 #endif
 492           }
 493           break;
 494         }
 495       }
 496       if (constructor == NULL) {
 497         // couldn't find constructor
 498 #ifndef PRODUCT
 499         if (PrintOptimizeStringConcat) {
 500           tty->print("giving up because couldn't find constructor ");
 501           alloc->jvms()->dump_spec(tty); tty->cr();
 502         }
 503 #endif
 504         break;
 505       }
 506 
 507       // Walked all the way back and found the constructor call so see
 508       // if this call converted into a direct string concatenation.
 509       sc->add_control(call);
 510       sc->add_control(constructor);
 511       sc->add_control(alloc);
 512       sc->set_allocation(alloc);
 513       if (sc->validate_control_flow()) {

 514         return sc;
 515       } else {
 516         return NULL;
 517       }
 518     } else if (cnode->method() == NULL) {
 519       break;
 520     } else if (!cnode->method()->is_static() &&
 521                cnode->method()->holder() == m->holder() &&
 522                cnode->method()->name() == ciSymbol::append_name() &&
 523                (cnode->method()->signature()->as_symbol() == string_sig ||
 524                 cnode->method()->signature()->as_symbol() == char_sig ||
 525                 cnode->method()->signature()->as_symbol() == int_sig)) {
 526       sc->add_control(cnode);
 527       Node* arg = cnode->in(TypeFunc::Parms + 1);
 528       if (cnode->method()->signature()->as_symbol() == int_sig) {
 529         sc->push_int(arg);
 530       } else if (cnode->method()->signature()->as_symbol() == char_sig) {
 531         sc->push_char(arg);
 532       } else {
 533         if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
 534           CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
 535           if (csj->method() != NULL &&
 536               csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
 537               arg->outcnt() == 1) {
 538             // _control is the list of StringBuilder calls nodes which
 539             // will be replaced by new String code after this optimization.
 540             // Integer::toString() call is not part of StringBuilder calls
 541             // chain. It could be eliminated only if its result is used
 542             // only by this SB calls chain.
 543             // Another limitation: it should be used only once because
 544             // it is unknown that it is used only by this SB calls chain
 545             // until all related SB calls nodes are collected.
 546             assert(arg->unique_out() == cnode, "sanity");
 547             sc->add_control(csj);
 548             sc->push_int(csj->in(TypeFunc::Parms));
 549             continue;
 550           }
 551         }
 552         sc->push_string(arg);
 553       }
 554       continue;
 555     } else {
 556       // some unhandled signature
 557 #ifndef PRODUCT
 558       if (PrintOptimizeStringConcat) {
 559         tty->print("giving up because encountered unexpected signature ");
 560         cnode->tf()->dump(); tty->cr();
 561         cnode->in(TypeFunc::Parms + 1)->dump();
 562       }
 563 #endif
 564       break;
 565     }
 566   }
 567   return NULL;
 568 }
 569 
 570 
 571 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
 572   Phase(StringOpts),
 573   _gvn(gvn),
 574   _visited(Thread::current()->resource_area()) {

 575 
 576   assert(OptimizeStringConcat, "shouldn't be here");
 577 
 578   size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
 579                                                                   ciSymbol::make("[I"), true);
 580   if (size_table_field == NULL) {
 581     // Something wrong so give up.
 582     assert(false, "why can't we find Integer.sizeTable?");
 583     return;
 584   }
 585 
 586   // Collect the types needed to talk about the various slices of memory
 587   char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
 588 
 589   // For each locally allocated StringBuffer see if the usages can be
 590   // collapsed into a single String construction.
 591 
 592   // Run through the list of allocation looking for SB.toString to see
 593   // if it's possible to fuse the usage of the SB into a single String
 594   // construction.
 595   GrowableArray<StringConcat*> concats;
 596   Node_List toStrings = collect_toString_calls();
 597   while (toStrings.size() > 0) {
 598     StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
 599     if (sc != NULL) {
 600       concats.push(sc);
 601     }
 602   }
 603 
 604   // try to coalesce separate concats
 605  restart:
 606   for (int c = 0; c < concats.length(); c++) {
 607     StringConcat* sc = concats.at(c);
 608     for (int i = 0; i < sc->num_arguments(); i++) {
 609       Node* arg = sc->argument_uncast(i);
 610       if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
 611         CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
 612         for (int o = 0; o < concats.length(); o++) {
 613           if (c == o) continue;
 614           StringConcat* other = concats.at(o);
 615           if (other->end() == csj) {
 616 #ifndef PRODUCT
 617             if (PrintOptimizeStringConcat) {
 618               tty->print_cr("considering stacked concats");
 619             }
 620 #endif
 621 
 622             StringConcat* merged = sc->merge(other, arg);
 623             if (merged->validate_control_flow()) {
 624 #ifndef PRODUCT
 625               if (PrintOptimizeStringConcat) {
 626                 tty->print_cr("stacking would succeed");
 627               }
 628 #endif
 629               if (c < o) {
 630                 concats.remove_at(o);
 631                 concats.at_put(c, merged);
 632               } else {
 633                 concats.remove_at(c);
 634                 concats.at_put(o, merged);
 635               }
 636               goto restart;
 637             } else {
 638 #ifndef PRODUCT
 639               if (PrintOptimizeStringConcat) {
 640                 tty->print_cr("stacking would fail");
 641               }
 642 #endif
 643             }
 644           }
 645         }
 646       }
 647     }
 648   }
 649 
 650 
 651   for (int c = 0; c < concats.length(); c++) {
 652     StringConcat* sc = concats.at(c);
 653     replace_string_concat(sc);
 654   }
 655 
 656   remove_dead_nodes();
 657 }
 658 
 659 void PhaseStringOpts::record_dead_node(Node* dead) {
 660   dead_worklist.push(dead);
 661 }
 662 
 663 void PhaseStringOpts::remove_dead_nodes() {
 664   // Delete any dead nodes to make things clean enough that escape
 665   // analysis doesn't get unhappy.
 666   while (dead_worklist.size() > 0) {
 667     Node* use = dead_worklist.pop();
 668     int opc = use->Opcode();
 669     switch (opc) {
 670       case Op_Region: {
 671         uint i = 1;
 672         for (i = 1; i < use->req(); i++) {
 673           if (use->in(i) != C->top()) {
 674             break;
 675           }
 676         }
 677         if (i >= use->req()) {
 678           for (SimpleDUIterator i(use); i.has_next(); i.next()) {
 679             Node* m = i.get();
 680             if (m->is_Phi()) {
 681               dead_worklist.push(m);
 682             }
 683           }
 684           C->gvn_replace_by(use, C->top());
 685         }
 686         break;
 687       }
 688       case Op_AddP:
 689       case Op_CreateEx: {
 690         // Recurisvely clean up references to CreateEx so EA doesn't
 691         // get unhappy about the partially collapsed graph.
 692         for (SimpleDUIterator i(use); i.has_next(); i.next()) {
 693           Node* m = i.get();
 694           if (m->is_AddP()) {
 695             dead_worklist.push(m);
 696           }
 697         }
 698         C->gvn_replace_by(use, C->top());
 699         break;
 700       }
 701       case Op_Phi:
 702         if (use->in(0) == C->top()) {
 703           C->gvn_replace_by(use, C->top());
 704         }
 705         break;
 706     }
 707   }
 708 }
 709 

































































































































 710 
 711 bool StringConcat::validate_control_flow() {
 712   // We found all the calls and arguments now lets see if it's
 713   // safe to transform the graph as we would expect.
 714 
 715   // Check to see if this resulted in too many uncommon traps previously
 716   if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
 717                         Deoptimization::Reason_intrinsic)) {
 718     return false;
 719   }
 720 
 721   // Walk backwards over the control flow from toString to the
 722   // allocation and make sure all the control flow is ok.  This
 723   // means it's either going to be eliminated once the calls are
 724   // removed or it can safely be transformed into an uncommon
 725   // trap.
 726 
 727   int null_check_count = 0;
 728   Unique_Node_List ctrl_path;
 729 
 730   assert(_control.contains(_begin), "missing");
 731   assert(_control.contains(_end), "missing");
 732 
 733   // Collect the nodes that we know about and will eliminate into ctrl_path
 734   for (uint i = 0; i < _control.size(); i++) {
 735     // Push the call and it's control projection
 736     Node* n = _control.at(i);
 737     if (n->is_Allocate()) {
 738       AllocateNode* an = n->as_Allocate();
 739       InitializeNode* init = an->initialization();
 740       ctrl_path.push(init);
 741       ctrl_path.push(init->as_Multi()->proj_out(0));
 742     }
 743     if (n->is_Call()) {
 744       CallNode* cn = n->as_Call();
 745       ctrl_path.push(cn);
 746       ctrl_path.push(cn->proj_out(0));
 747       ctrl_path.push(cn->proj_out(0)->unique_out());
 748       if (cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0) != NULL) {
 749         ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
 750       }
 751     } else {
 752       ShouldNotReachHere();
 753     }
 754   }
 755 
 756   // Skip backwards through the control checking for unexpected contro flow
 757   Node* ptr = _end;
 758   bool fail = false;
 759   while (ptr != _begin) {
 760     if (ptr->is_Call() && ctrl_path.member(ptr)) {
 761       ptr = ptr->in(0);
 762     } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
 763       ptr = ptr->in(0)->in(0)->in(0);
 764       assert(ctrl_path.member(ptr), "should be a known piece of control");
 765     } else if (ptr->is_IfTrue()) {
 766       IfNode* iff = ptr->in(0)->as_If();
 767       BoolNode* b = iff->in(1)->isa_Bool();
 768 
 769       if (b == NULL) {
 770         fail = true;
 771         break;
 772       }
 773 
 774       Node* cmp = b->in(1);
 775       Node* v1 = cmp->in(1);
 776       Node* v2 = cmp->in(2);
 777       Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
 778 
 779       // Null check of the return of append which can simply be eliminated
 780       if (b->_test._test == BoolTest::ne &&
 781           v2->bottom_type() == TypePtr::NULL_PTR &&
 782           v1->is_Proj() && ctrl_path.member(v1->in(0))) {
 783         // NULL check of the return value of the append
 784         null_check_count++;
 785         if (otherproj->outcnt() == 1) {
 786           CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
 787           if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
 788             ctrl_path.push(call);
 789           }
 790         }
 791         _control.push(ptr);
 792         ptr = ptr->in(0)->in(0);
 793         continue;
 794       }
 795 
 796       // A test which leads to an uncommon trap which should be safe.
 797       // Later this trap will be converted into a trap that restarts
 798       // at the beginning.
 799       if (otherproj->outcnt() == 1) {
 800         CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
 801         if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
 802           // control flow leads to uct so should be ok
 803           _uncommon_traps.push(call);
 804           ctrl_path.push(call);
 805           ptr = ptr->in(0)->in(0);
 806           continue;
 807         }
 808       }
 809 
 810 #ifndef PRODUCT
 811       // Some unexpected control flow we don't know how to handle.
 812       if (PrintOptimizeStringConcat) {
 813         tty->print_cr("failing with unknown test");
 814         b->dump();
 815         cmp->dump();
 816         v1->dump();
 817         v2->dump();
 818         tty->cr();
 819       }
 820 #endif
 821       fail = true;
 822       break;
 823     } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
 824       ptr = ptr->in(0)->in(0);
 825     } else if (ptr->is_Region()) {
 826       Node* copy = ptr->as_Region()->is_copy();
 827       if (copy != NULL) {
 828         ptr = copy;
 829         continue;
 830       }
 831       if (ptr->req() == 3 &&
 832           ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
 833           ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
 834           ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
 835           ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
 836         // Simple diamond.
 837         // XXX should check for possibly merging stores.  simple data merges are ok.
 838         // The IGVN will make this simple diamond go away when it
 839         // transforms the Region. Make sure it sees it.
 840         Compile::current()->record_for_igvn(ptr);
 841         ptr = ptr->in(1)->in(0)->in(0);
 842         continue;
 843       }
 844 #ifndef PRODUCT
 845       if (PrintOptimizeStringConcat) {
 846         tty->print_cr("fusion would fail for region");
 847         _begin->dump();
 848         ptr->dump(2);
 849       }
 850 #endif
 851       fail = true;
 852       break;
 853     } else {
 854       // other unknown control
 855       if (!fail) {
 856 #ifndef PRODUCT
 857         if (PrintOptimizeStringConcat) {
 858           tty->print_cr("fusion would fail for");
 859           _begin->dump();
 860         }
 861 #endif
 862         fail = true;
 863       }
 864 #ifndef PRODUCT
 865       if (PrintOptimizeStringConcat) {
 866         ptr->dump();
 867       }
 868 #endif
 869       ptr = ptr->in(0);
 870     }
 871   }
 872 #ifndef PRODUCT
 873   if (PrintOptimizeStringConcat && fail) {
 874     tty->cr();
 875   }
 876 #endif
 877   if (fail) return !fail;
 878 
 879   // Validate that all these results produced are contained within
 880   // this cluster of objects.  First collect all the results produced
 881   // by calls in the region.
 882   _stringopts->_visited.Clear();
 883   Node_List worklist;
 884   Node* final_result = _end->proj_out(TypeFunc::Parms);
 885   for (uint i = 0; i < _control.size(); i++) {
 886     CallNode* cnode = _control.at(i)->isa_Call();
 887     if (cnode != NULL) {
 888       _stringopts->_visited.test_set(cnode->_idx);
 889     }
 890     Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
 891     if (result != NULL && result != final_result) {
 892       worklist.push(result);
 893     }
 894   }
 895 
 896   Node* last_result = NULL;
 897   while (worklist.size() > 0) {
 898     Node* result = worklist.pop();
 899     if (_stringopts->_visited.test_set(result->_idx))
 900       continue;
 901     for (SimpleDUIterator i(result); i.has_next(); i.next()) {
 902       Node *use = i.get();
 903       if (ctrl_path.member(use)) {
 904         // already checked this
 905         continue;
 906       }
 907       int opc = use->Opcode();
 908       if (opc == Op_CmpP || opc == Op_Node) {
 909         ctrl_path.push(use);
 910         continue;
 911       }
 912       if (opc == Op_CastPP || opc == Op_CheckCastPP) {
 913         for (SimpleDUIterator j(use); j.has_next(); j.next()) {
 914           worklist.push(j.get());
 915         }
 916         worklist.push(use->in(1));
 917         ctrl_path.push(use);
 918         continue;
 919       }
 920 #ifndef PRODUCT
 921       if (PrintOptimizeStringConcat) {
 922         if (result != last_result) {
 923           last_result = result;
 924           tty->print_cr("extra uses for result:");
 925           last_result->dump();
 926         }
 927         use->dump();
 928       }
 929 #endif
 930       fail = true;
 931       break;
 932     }
 933   }
 934 
 935 #ifndef PRODUCT
 936   if (PrintOptimizeStringConcat && !fail) {
 937     ttyLocker ttyl;
 938     tty->cr();
 939     tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
 940     _begin->jvms()->dump_spec(tty); tty->cr();
 941     for (int i = 0; i < num_arguments(); i++) {
 942       argument(i)->dump();
 943     }
 944     _control.dump();
 945     tty->cr();
 946   }
 947 #endif
 948 
 949   return !fail;
 950 }
 951 
 952 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
 953   const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
 954   Node* klass_node = __ makecon(mirror_type);
 955   BasicType bt = field->layout_type();
 956   ciType* field_klass = field->type();
 957 
 958   const Type *type;
 959   if( bt == T_OBJECT ) {
 960     if (!field->type()->is_loaded()) {
 961       type = TypeInstPtr::BOTTOM;
 962     } else if (field->is_constant()) {
 963       // This can happen if the constant oop is non-perm.
 964       ciObject* con = field->constant_value().as_object();
 965       // Do not "join" in the previous type; it doesn't add value,
 966       // and may yield a vacuous result if the field is of interface type.
 967       type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
 968       assert(type != NULL, "field singleton type must be consistent");
 969       return __ makecon(type);
 970     } else {
 971       type = TypeOopPtr::make_from_klass(field_klass->as_klass());
 972     }
 973   } else {
 974     type = Type::get_const_basic_type(bt);
 975   }
 976 
 977   return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
 978                        type, T_OBJECT,
 979                        C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())));
 980 }
 981 
 982 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
 983   RegionNode *final_merge = new (C) RegionNode(3);
 984   kit.gvn().set_type(final_merge, Type::CONTROL);
 985   Node* final_size = new (C) PhiNode(final_merge, TypeInt::INT);
 986   kit.gvn().set_type(final_size, TypeInt::INT);
 987 
 988   IfNode* iff = kit.create_and_map_if(kit.control(),
 989                                       __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
 990                                       PROB_FAIR, COUNT_UNKNOWN);
 991   Node* is_min = __ IfFalse(iff);
 992   final_merge->init_req(1, is_min);
 993   final_size->init_req(1, __ intcon(11));
 994 
 995   kit.set_control(__ IfTrue(iff));
 996   if (kit.stopped()) {
 997     final_merge->init_req(2, C->top());
 998     final_size->init_req(2, C->top());
 999   } else {
1000 
1001     // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1002     RegionNode *r = new (C) RegionNode(3);
1003     kit.gvn().set_type(r, Type::CONTROL);
1004     Node *phi = new (C) PhiNode(r, TypeInt::INT);
1005     kit.gvn().set_type(phi, TypeInt::INT);
1006     Node *size = new (C) PhiNode(r, TypeInt::INT);
1007     kit.gvn().set_type(size, TypeInt::INT);
1008     Node* chk = __ CmpI(arg, __ intcon(0));
1009     Node* p = __ Bool(chk, BoolTest::lt);
1010     IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1011     Node* lessthan = __ IfTrue(iff);
1012     Node* greaterequal = __ IfFalse(iff);
1013     r->init_req(1, lessthan);
1014     phi->init_req(1, __ SubI(__ intcon(0), arg));
1015     size->init_req(1, __ intcon(1));
1016     r->init_req(2, greaterequal);
1017     phi->init_req(2, arg);
1018     size->init_req(2, __ intcon(0));
1019     kit.set_control(r);
1020     C->record_for_igvn(r);
1021     C->record_for_igvn(phi);
1022     C->record_for_igvn(size);
1023 
1024     // for (int i=0; ; i++)
1025     //   if (x <= sizeTable[i])
1026     //     return i+1;
1027 
1028     // Add loop predicate first.
1029     kit.add_predicate();
1030 
1031     RegionNode *loop = new (C) RegionNode(3);
1032     loop->init_req(1, kit.control());
1033     kit.gvn().set_type(loop, Type::CONTROL);
1034 
1035     Node *index = new (C) PhiNode(loop, TypeInt::INT);
1036     index->init_req(1, __ intcon(0));
1037     kit.gvn().set_type(index, TypeInt::INT);
1038     kit.set_control(loop);
1039     Node* sizeTable = fetch_static_field(kit, size_table_field);
1040 
1041     Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1042     C->record_for_igvn(value);
1043     Node* limit = __ CmpI(phi, value);
1044     Node* limitb = __ Bool(limit, BoolTest::le);
1045     IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1046     Node* lessEqual = __ IfTrue(iff2);
1047     Node* greater = __ IfFalse(iff2);
1048 
1049     loop->init_req(2, greater);
1050     index->init_req(2, __ AddI(index, __ intcon(1)));
1051 
1052     kit.set_control(lessEqual);
1053     C->record_for_igvn(loop);
1054     C->record_for_igvn(index);
1055 
1056     final_merge->init_req(2, kit.control());
1057     final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1058   }
1059 
1060   kit.set_control(final_merge);
1061   C->record_for_igvn(final_merge);
1062   C->record_for_igvn(final_size);
1063 
1064   return final_size;
1065 }
1066 
1067 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1068   RegionNode *final_merge = new (C) RegionNode(4);
1069   kit.gvn().set_type(final_merge, Type::CONTROL);
1070   Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1071   kit.gvn().set_type(final_mem, Type::MEMORY);
1072 
1073   // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1074   {
1075     // i == MIN_VALUE
1076     IfNode* iff = kit.create_and_map_if(kit.control(),
1077                                         __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1078                                         PROB_FAIR, COUNT_UNKNOWN);
1079 
1080     Node* old_mem = kit.memory(char_adr_idx);
1081 
1082     kit.set_control(__ IfFalse(iff));
1083     if (kit.stopped()) {
1084       // Statically not equal to MIN_VALUE so this path is dead
1085       final_merge->init_req(3, kit.control());
1086     } else {
1087       copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1088                   char_array, start);
1089       final_merge->init_req(3, kit.control());
1090       final_mem->init_req(3, kit.memory(char_adr_idx));
1091     }
1092 
1093     kit.set_control(__ IfTrue(iff));
1094     kit.set_memory(old_mem, char_adr_idx);
1095   }
1096 
1097 
1098   // Simplified version of Integer.getChars
1099 
1100   // int q, r;
1101   // int charPos = index;
1102   Node* charPos = end;
1103 
1104   // char sign = 0;
1105 
1106   Node* i = arg;
1107   Node* sign = __ intcon(0);
1108 
1109   // if (i < 0) {
1110   //     sign = '-';
1111   //     i = -i;
1112   // }
1113   {
1114     IfNode* iff = kit.create_and_map_if(kit.control(),
1115                                         __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1116                                         PROB_FAIR, COUNT_UNKNOWN);
1117 
1118     RegionNode *merge = new (C) RegionNode(3);
1119     kit.gvn().set_type(merge, Type::CONTROL);
1120     i = new (C) PhiNode(merge, TypeInt::INT);
1121     kit.gvn().set_type(i, TypeInt::INT);
1122     sign = new (C) PhiNode(merge, TypeInt::INT);
1123     kit.gvn().set_type(sign, TypeInt::INT);
1124 
1125     merge->init_req(1, __ IfTrue(iff));
1126     i->init_req(1, __ SubI(__ intcon(0), arg));
1127     sign->init_req(1, __ intcon('-'));
1128     merge->init_req(2, __ IfFalse(iff));
1129     i->init_req(2, arg);
1130     sign->init_req(2, __ intcon(0));
1131 
1132     kit.set_control(merge);
1133 
1134     C->record_for_igvn(merge);
1135     C->record_for_igvn(i);
1136     C->record_for_igvn(sign);
1137   }
1138 
1139   // for (;;) {
1140   //     q = i / 10;
1141   //     r = i - ((q << 3) + (q << 1));  // r = i-(q*10) ...
1142   //     buf [--charPos] = digits [r];
1143   //     i = q;
1144   //     if (i == 0) break;
1145   // }
1146 
1147   {
1148     // Add loop predicate first.
1149     kit.add_predicate();
1150 
1151     RegionNode *head = new (C) RegionNode(3);
1152     head->init_req(1, kit.control());
1153     kit.gvn().set_type(head, Type::CONTROL);
1154     Node *i_phi = new (C) PhiNode(head, TypeInt::INT);
1155     i_phi->init_req(1, i);
1156     kit.gvn().set_type(i_phi, TypeInt::INT);
1157     charPos = PhiNode::make(head, charPos);
1158     kit.gvn().set_type(charPos, TypeInt::INT);
1159     Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1160     kit.gvn().set_type(mem, Type::MEMORY);
1161     kit.set_control(head);
1162     kit.set_memory(mem, char_adr_idx);
1163 
1164     Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1165     Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1166                                      __ LShiftI(q, __ intcon(1))));
1167     Node* m1 = __ SubI(charPos, __ intcon(1));
1168     Node* ch = __ AddI(r, __ intcon('0'));
1169 
1170     Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1171                                   ch, T_CHAR, char_adr_idx);
1172 
1173 
1174     IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1175                                         PROB_FAIR, COUNT_UNKNOWN);
1176     Node* ne = __ IfTrue(iff);
1177     Node* eq = __ IfFalse(iff);
1178 
1179     head->init_req(2, ne);
1180     mem->init_req(2, st);
1181     i_phi->init_req(2, q);
1182     charPos->init_req(2, m1);
1183 
1184     charPos = m1;
1185 
1186     kit.set_control(eq);
1187     kit.set_memory(st, char_adr_idx);
1188 
1189     C->record_for_igvn(head);
1190     C->record_for_igvn(mem);
1191     C->record_for_igvn(i_phi);
1192     C->record_for_igvn(charPos);
1193   }
1194 
1195   {
1196     // if (sign != 0) {
1197     //     buf [--charPos] = sign;
1198     // }
1199     IfNode* iff = kit.create_and_map_if(kit.control(),
1200                                         __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1201                                         PROB_FAIR, COUNT_UNKNOWN);
1202 
1203     final_merge->init_req(2, __ IfFalse(iff));
1204     final_mem->init_req(2, kit.memory(char_adr_idx));
1205 
1206     kit.set_control(__ IfTrue(iff));
1207     if (kit.stopped()) {
1208       final_merge->init_req(1, C->top());
1209       final_mem->init_req(1, C->top());
1210     } else {
1211       Node* m1 = __ SubI(charPos, __ intcon(1));
1212       Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1213                                     sign, T_CHAR, char_adr_idx);
1214 
1215       final_merge->init_req(1, kit.control());
1216       final_mem->init_req(1, st);
1217     }
1218 
1219     kit.set_control(final_merge);
1220     kit.set_memory(final_mem, char_adr_idx);
1221 
1222     C->record_for_igvn(final_merge);
1223     C->record_for_igvn(final_mem);
1224   }
1225 }
1226 
1227 
1228 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1229   Node* string = str;
1230   Node* offset = kit.load_String_offset(kit.control(), string);
1231   Node* count  = kit.load_String_length(kit.control(), string);
1232   Node* value  = kit.load_String_value (kit.control(), string);
1233 
1234   // copy the contents
1235   if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1236     // For small constant strings just emit individual stores.
1237     // A length of 6 seems like a good space/speed tradeof.
1238     int c = count->get_int();
1239     int o = offset->get_int();
1240     const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1241     ciTypeArray* value_array = t->const_oop()->as_type_array();
1242     for (int e = 0; e < c; e++) {
1243       __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1244                          __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1245       start = __ AddI(start, __ intcon(1));
1246     }
1247   } else {
1248     Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1249     Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1250     Node* c = count;
1251     Node* extra = NULL;
1252 #ifdef _LP64
1253     c = __ ConvI2L(c);
1254     extra = C->top();
1255 #endif
1256     Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1257                                        OptoRuntime::fast_arraycopy_Type(),
1258                                        CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1259                                        "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1260                                        src_ptr, dst_ptr, c, extra);
1261     start = __ AddI(start, count);
1262   }
1263   return start;
1264 }
1265 
1266 
1267 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1268   // Log a little info about the transformation
1269   sc->maybe_log_transform();
1270 
1271   // pull the JVMState of the allocation into a SafePointNode to serve as
1272   // as a shim for the insertion of the new code.
1273   JVMState* jvms     = sc->begin()->jvms()->clone_shallow(C);
1274   uint size = sc->begin()->req();
1275   SafePointNode* map = new (C) SafePointNode(size, jvms);
1276 
1277   // copy the control and memory state from the final call into our
1278   // new starting state.  This allows any preceeding tests to feed
1279   // into the new section of code.
1280   for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1281     map->init_req(i1, sc->end()->in(i1));
1282   }
1283   // blow away old allocation arguments
1284   for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1285     map->init_req(i1, C->top());
1286   }
1287   // Copy the rest of the inputs for the JVMState
1288   for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1289     map->init_req(i1, sc->begin()->in(i1));
1290   }
1291   // Make sure the memory state is a MergeMem for parsing.
1292   if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1293     map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1294   }
1295 
1296   jvms->set_map(map);
1297   map->ensure_stack(jvms, jvms->method()->max_stack());
1298 
1299 
1300   // disconnect all the old StringBuilder calls from the graph
1301   sc->eliminate_unneeded_control();
1302 
1303   // At this point all the old work has been completely removed from
1304   // the graph and the saved JVMState exists at the point where the
1305   // final toString call used to be.
1306   GraphKit kit(jvms);
1307 
1308   // There may be uncommon traps which are still using the
1309   // intermediate states and these need to be rewritten to point at
1310   // the JVMState at the beginning of the transformation.
1311   sc->convert_uncommon_traps(kit, jvms);
1312 
1313   // Now insert the logic to compute the size of the string followed
1314   // by all the logic to construct array and resulting string.
1315 
1316   Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1317 
1318   // Create a region for the overflow checks to merge into.
1319   int args = MAX2(sc->num_arguments(), 1);
1320   RegionNode* overflow = new (C) RegionNode(args);
1321   kit.gvn().set_type(overflow, Type::CONTROL);
1322 
1323   // Create a hook node to hold onto the individual sizes since they
1324   // are need for the copying phase.
1325   Node* string_sizes = new (C) Node(args);
1326 
1327   Node* length = __ intcon(0);
1328   for (int argi = 0; argi < sc->num_arguments(); argi++) {
1329     Node* arg = sc->argument(argi);
1330     switch (sc->mode(argi)) {
1331       case StringConcat::IntMode: {
1332         Node* string_size = int_stringSize(kit, arg);
1333 
1334         // accumulate total
1335         length = __ AddI(length, string_size);
1336 
1337         // Cache this value for the use by int_toString
1338         string_sizes->init_req(argi, string_size);
1339         break;
1340       }
1341       case StringConcat::StringNullCheckMode: {
1342         const Type* type = kit.gvn().type(arg);
1343         assert(type != TypePtr::NULL_PTR, "missing check");
1344         if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1345           // Null check with uncommont trap since
1346           // StringBuilder(null) throws exception.
1347           // Use special uncommon trap instead of
1348           // calling normal do_null_check().
1349           Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1350           IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1351           overflow->add_req(__ IfFalse(iff));
1352           Node* notnull = __ IfTrue(iff);
1353           kit.set_control(notnull); // set control for the cast_not_null
1354           arg = kit.cast_not_null(arg, false);
1355           sc->set_argument(argi, arg);
1356         }
1357         assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1358         // Fallthrough to add string length.
1359       }
1360       case StringConcat::StringMode: {
1361         const Type* type = kit.gvn().type(arg);
1362         if (type == TypePtr::NULL_PTR) {
1363           // replace the argument with the null checked version
1364           arg = null_string;
1365           sc->set_argument(argi, arg);
1366         } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1367           // s = s != null ? s : "null";
1368           // length = length + (s.count - s.offset);
1369           RegionNode *r = new (C) RegionNode(3);
1370           kit.gvn().set_type(r, Type::CONTROL);
1371           Node *phi = new (C) PhiNode(r, type);
1372           kit.gvn().set_type(phi, phi->bottom_type());
1373           Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1374           IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1375           Node* notnull = __ IfTrue(iff);
1376           Node* isnull =  __ IfFalse(iff);
1377           kit.set_control(notnull); // set control for the cast_not_null
1378           r->init_req(1, notnull);
1379           phi->init_req(1, kit.cast_not_null(arg, false));
1380           r->init_req(2, isnull);
1381           phi->init_req(2, null_string);
1382           kit.set_control(r);
1383           C->record_for_igvn(r);
1384           C->record_for_igvn(phi);
1385           // replace the argument with the null checked version
1386           arg = phi;
1387           sc->set_argument(argi, arg);
1388         }
1389 
1390         Node* count = kit.load_String_length(kit.control(), arg);
1391 
1392         length = __ AddI(length, count);
1393         string_sizes->init_req(argi, NULL);
1394         break;
1395       }
1396       case StringConcat::CharMode: {
1397         // one character only
1398         length = __ AddI(length, __ intcon(1));
1399         break;
1400       }
1401       default:
1402         ShouldNotReachHere();
1403     }
1404     if (argi > 0) {
1405       // Check that the sum hasn't overflowed
1406       IfNode* iff = kit.create_and_map_if(kit.control(),
1407                                           __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1408                                           PROB_MIN, COUNT_UNKNOWN);
1409       kit.set_control(__ IfFalse(iff));
1410       overflow->set_req(argi, __ IfTrue(iff));
1411     }
1412   }
1413 
1414   {
1415     // Hook
1416     PreserveJVMState pjvms(&kit);
1417     kit.set_control(overflow);
1418     C->record_for_igvn(overflow);
1419     kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1420                       Deoptimization::Action_make_not_entrant);
1421   }
1422 
1423   Node* result;
1424   if (!kit.stopped()) {
1425 
1426     // length now contains the number of characters needed for the
1427     // char[] so create a new AllocateArray for the char[]
1428     Node* char_array = NULL;
1429     {
1430       PreserveReexecuteState preexecs(&kit);
1431       // The original jvms is for an allocation of either a String or
1432       // StringBuffer so no stack adjustment is necessary for proper
1433       // reexecution.  If we deoptimize in the slow path the bytecode
1434       // will be reexecuted and the char[] allocation will be thrown away.
1435       kit.jvms()->set_should_reexecute(true);
1436       char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1437                                  length, 1);
1438     }
1439 
1440     // Mark the allocation so that zeroing is skipped since the code
1441     // below will overwrite the entire array
1442     AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1443     char_alloc->maybe_set_complete(_gvn);
1444 
1445     // Now copy the string representations into the final char[]
1446     Node* start = __ intcon(0);
1447     for (int argi = 0; argi < sc->num_arguments(); argi++) {
1448       Node* arg = sc->argument(argi);
1449       switch (sc->mode(argi)) {
1450         case StringConcat::IntMode: {
1451           Node* end = __ AddI(start, string_sizes->in(argi));
1452           // getChars words backwards so pass the ending point as well as the start
1453           int_getChars(kit, arg, char_array, start, end);
1454           start = end;
1455           break;
1456         }
1457         case StringConcat::StringNullCheckMode:
1458         case StringConcat::StringMode: {
1459           start = copy_string(kit, arg, char_array, start);
1460           break;
1461         }
1462         case StringConcat::CharMode: {
1463           __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1464                              arg, T_CHAR, char_adr_idx);
1465           start = __ AddI(start, __ intcon(1));
1466           break;
1467         }
1468         default:
1469           ShouldNotReachHere();
1470       }
1471     }
1472 
1473     // If we're not reusing an existing String allocation then allocate one here.
1474     result = sc->string_alloc();
1475     if (result == NULL) {
1476       PreserveReexecuteState preexecs(&kit);
1477       // The original jvms is for an allocation of either a String or
1478       // StringBuffer so no stack adjustment is necessary for proper
1479       // reexecution.
1480       kit.jvms()->set_should_reexecute(true);
1481       result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1482     }
1483 
1484     // Intialize the string
1485     if (java_lang_String::has_offset_field()) {
1486       kit.store_String_offset(kit.control(), result, __ intcon(0));
1487       kit.store_String_length(kit.control(), result, length);
1488     }
1489     kit.store_String_value(kit.control(), result, char_array);
1490   } else {
1491     result = C->top();
1492   }
1493   // hook up the outgoing control and result
1494   kit.replace_call(sc->end(), result);
1495 
1496   // Unhook any hook nodes
1497   string_sizes->disconnect_inputs(NULL, C);
1498   sc->cleanup();
1499 }
--- EOF ---