1 /*

     2  * Copyright 2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 #include "incls/_precompiled.incl"

    26 #include "incls/_stringopts.cpp.incl"

    27 

    28 #define __ kit.

    29 

    30 class StringConcat : public ResourceObj {

    31  private:

    32   PhaseStringOpts*    _stringopts;

    33   Node*               _string_alloc;

    34   AllocateNode*       _begin;          // The allocation the begins the pattern

    35   CallStaticJavaNode* _end;            // The final call of the pattern.  Will either be

    36                                        // SB.toString or or String.<init>(SB.toString)

    37   bool                _multiple;       // indicates this is a fusion of two or more

    38                                        // separate StringBuilders

    39 

    40   Node*               _arguments;      // The list of arguments to be concatenated

    41   GrowableArray<int>  _mode;           // into a String along with a mode flag

    42                                        // indicating how to treat the value.

    43 

    44   Node_List           _control;        // List of control nodes that will be deleted

    45   Node_List           _uncommon_traps; // Uncommon traps that needs to be rewritten

    46                                        // to restart at the initial JVMState.

    47  public:

    48   // Mode for converting arguments to Strings

    49   enum {

    50     StringMode,

    51     IntMode,

    52     CharMode

    53   };

    54 

    55   StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):

    56     _end(end),

    57     _begin(NULL),

    58     _multiple(false),

    59     _string_alloc(NULL),

    60     _stringopts(stringopts) {

    61     _arguments = new (_stringopts->C, 1) Node(1);

    62     _arguments->del_req(0);

    63   }

    64 

    65   bool validate_control_flow();

    66 

    67   void merge_add() {

    68 #if 0

    69     // XXX This is place holder code for reusing an existing String

    70     // allocation but the logic for checking the state safety is

    71     // probably inadequate at the moment.

    72     CallProjections endprojs;

    73     sc->end()->extract_projections(&endprojs, false);

    74     if (endprojs.resproj != NULL) {

    75       for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {

    76         CallStaticJavaNode *use = i.get()->isa_CallStaticJava();

    77         if (use != NULL && use->method() != NULL &&

    78             use->method()->holder() == C->env()->String_klass() &&

    79             use->method()->name() == ciSymbol::object_initializer_name() &&

    80             use->in(TypeFunc::Parms + 1) == endprojs.resproj) {

    81           // Found useless new String(sb.toString()) so reuse the newly allocated String

    82           // when creating the result instead of allocating a new one.

    83           sc->set_string_alloc(use->in(TypeFunc::Parms));

    84           sc->set_end(use);

    85         }

    86       }

    87     }

    88 #endif

    89   }

    90 

    91   StringConcat* merge(StringConcat* other, Node* arg);

    92 

    93   void set_allocation(AllocateNode* alloc) {

    94     _begin = alloc;

    95   }

    96 

    97   void append(Node* value, int mode) {

    98     _arguments->add_req(value);

    99     _mode.append(mode);

   100   }

   101   void push(Node* value, int mode) {

   102     _arguments->ins_req(0, value);

   103     _mode.insert_before(0, mode);

   104   }

   105   void push_string(Node* value) {

   106     push(value, StringMode);

   107   }

   108   void push_int(Node* value) {

   109     push(value, IntMode);

   110   }

   111   void push_char(Node* value) {

   112     push(value, CharMode);

   113   }

   114 

   115   Node* argument(int i) {

   116     return _arguments->in(i);

   117   }

   118   void set_argument(int i, Node* value) {

   119     _arguments->set_req(i, value);

   120   }

   121   int num_arguments() {

   122     return _mode.length();

   123   }

   124   int mode(int i) {

   125     return _mode.at(i);

   126   }

   127   void add_control(Node* ctrl) {

   128     assert(!_control.contains(ctrl), "only push once");

   129     _control.push(ctrl);

   130   }

   131   CallStaticJavaNode* end() { return _end; }

   132   AllocateNode* begin() { return _begin; }

   133   Node* string_alloc() { return _string_alloc; }

   134 

   135   void eliminate_unneeded_control();

   136   void eliminate_initialize(InitializeNode* init);

   137   void eliminate_call(CallNode* call);

   138 

   139   void maybe_log_transform() {

   140     CompileLog* log = _stringopts->C->log();

   141     if (log != NULL) {

   142       log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",

   143                 num_arguments(),

   144                 _string_alloc != NULL,

   145                 _multiple);

   146       JVMState* p = _begin->jvms();

   147       while (p != NULL) {

   148         log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));

   149         p = p->caller();

   150       }

   151       log->tail("replace_string_concat");

   152     }

   153   }

   154 

   155   void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {

   156     for (uint u = 0; u < _uncommon_traps.size(); u++) {

   157       Node* uct = _uncommon_traps.at(u);

   158 

   159       // Build a new call using the jvms state of the allocate

   160       address call_addr = SharedRuntime::uncommon_trap_blob()->instructions_begin();

   161       const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();

   162       int size = call_type->domain()->cnt();

   163       const TypePtr* no_memory_effects = NULL;

   164       Compile* C = _stringopts->C;

   165       CallStaticJavaNode* call = new (C, size) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",

   166                                                                   jvms->bci(), no_memory_effects);

   167       for (int e = 0; e < TypeFunc::Parms; e++) {

   168         call->init_req(e, uct->in(e));

   169       }

   170       // Set the trap request to record intrinsic failure if this trap

   171       // is taken too many times.  Ideally we would handle then traps by

   172       // doing the original bookkeeping in the MDO so that if it caused

   173       // the code to be thrown out we could still recompile and use the

   174       // optimization.  Failing the uncommon traps doesn't really mean

   175       // that the optimization is a bad idea but there's no other way to

   176       // do the MDO updates currently.

   177       int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,

   178                                                            Deoptimization::Action_make_not_entrant);

   179       call->init_req(TypeFunc::Parms, __ intcon(trap_request));

   180       kit.add_safepoint_edges(call);

   181 

   182       _stringopts->gvn()->transform(call);

   183       C->gvn_replace_by(uct, call);

   184       uct->disconnect_inputs(NULL);

   185     }

   186   }

   187 

   188   void cleanup() {

   189     // disconnect the hook node

   190     _arguments->disconnect_inputs(NULL);

   191   }

   192 };

   193 

   194 

   195 void StringConcat::eliminate_unneeded_control() {

   196   eliminate_initialize(begin()->initialization());

   197   for (uint i = 0; i < _control.size(); i++) {

   198     Node* n = _control.at(i);

   199     if (n->is_Call()) {

   200       if (n != _end) {

   201         eliminate_call(n->as_Call());

   202       }

   203     } else if (n->is_IfTrue()) {

   204       Compile* C = _stringopts->C;

   205       C->gvn_replace_by(n, n->in(0)->in(0));

   206       C->gvn_replace_by(n->in(0), C->top());

   207     }

   208   }

   209 }

   210 

   211 

   212 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {

   213   StringConcat* result = new StringConcat(_stringopts, _end);

   214   for (uint x = 0; x < _control.size(); x++) {

   215     Node* n = _control.at(x);

   216     if (n->is_Call()) {

   217       result->_control.push(n);

   218     }

   219   }

   220   for (uint x = 0; x < other->_control.size(); x++) {

   221     Node* n = other->_control.at(x);

   222     if (n->is_Call()) {

   223       result->_control.push(n);

   224     }

   225   }

   226   assert(result->_control.contains(other->_end), "what?");

   227   assert(result->_control.contains(_begin), "what?");

   228   for (int x = 0; x < num_arguments(); x++) {

   229     if (argument(x) == arg) {

   230       // replace the toString result with the all the arguments that

   231       // made up the other StringConcat

   232       for (int y = 0; y < other->num_arguments(); y++) {

   233         result->append(other->argument(y), other->mode(y));

   234       }

   235     } else {

   236       result->append(argument(x), mode(x));

   237     }

   238   }

   239   result->set_allocation(other->_begin);

   240   result->_multiple = true;

   241   return result;

   242 }

   243 

   244 

   245 void StringConcat::eliminate_call(CallNode* call) {

   246   Compile* C = _stringopts->C;

   247   CallProjections projs;

   248   call->extract_projections(&projs, false);

   249   if (projs.fallthrough_catchproj != NULL) {

   250     C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));

   251   }

   252   if (projs.fallthrough_memproj != NULL) {

   253     C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));

   254   }

   255   if (projs.catchall_memproj != NULL) {

   256     C->gvn_replace_by(projs.catchall_memproj, C->top());

   257   }

   258   if (projs.fallthrough_ioproj != NULL) {

   259     C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));

   260   }

   261   if (projs.catchall_ioproj != NULL) {

   262     C->gvn_replace_by(projs.catchall_ioproj, C->top());

   263   }

   264   if (projs.catchall_catchproj != NULL) {

   265     // EA can't cope with the partially collapsed graph this

   266     // creates so put it on the worklist to be collapsed later.

   267     for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {

   268       Node *use = i.get();

   269       int opc = use->Opcode();

   270       if (opc == Op_CreateEx || opc == Op_Region) {

   271         _stringopts->record_dead_node(use);

   272       }

   273     }

   274     C->gvn_replace_by(projs.catchall_catchproj, C->top());

   275   }

   276   if (projs.resproj != NULL) {

   277     C->gvn_replace_by(projs.resproj, C->top());

   278   }

   279   C->gvn_replace_by(call, C->top());

   280 }

   281 

   282 void StringConcat::eliminate_initialize(InitializeNode* init) {

   283   Compile* C = _stringopts->C;

   284 

   285   // Eliminate Initialize node.

   286   assert(init->outcnt() <= 2, "only a control and memory projection expected");

   287   assert(init->req() <= InitializeNode::RawStores, "no pending inits");

   288   Node *ctrl_proj = init->proj_out(TypeFunc::Control);

   289   if (ctrl_proj != NULL) {

   290     C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));

   291   }

   292   Node *mem_proj = init->proj_out(TypeFunc::Memory);

   293   if (mem_proj != NULL) {

   294     Node *mem = init->in(TypeFunc::Memory);

   295     C->gvn_replace_by(mem_proj, mem);

   296   }

   297   C->gvn_replace_by(init, C->top());

   298   init->disconnect_inputs(NULL);

   299 }

   300 

   301 Node_List PhaseStringOpts::collect_toString_calls() {

   302   Node_List string_calls;

   303   Node_List worklist;

   304 

   305   _visited.Clear();

   306 

   307   // Prime the worklist

   308   for (uint i = 1; i < C->root()->len(); i++) {

   309     Node* n = C->root()->in(i);

   310     if (n != NULL && !_visited.test_set(n->_idx)) {

   311       worklist.push(n);

   312     }

   313   }

   314 

   315   while (worklist.size() > 0) {

   316     Node* ctrl = worklist.pop();

   317     if (ctrl->is_CallStaticJava()) {

   318       CallStaticJavaNode* csj = ctrl->as_CallStaticJava();

   319       ciMethod* m = csj->method();

   320       if (m != NULL &&

   321           (m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString ||

   322            m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString)) {

   323         string_calls.push(csj);

   324       }

   325     }

   326     if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {

   327       worklist.push(ctrl->in(0));

   328     }

   329     if (ctrl->is_Region()) {

   330       for (uint i = 1; i < ctrl->len(); i++) {

   331         if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {

   332           worklist.push(ctrl->in(i));

   333         }

   334       }

   335     }

   336   }

   337   return string_calls;

   338 }

   339 

   340 

   341 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {

   342   ciMethod* m = call->method();

   343   ciSymbol* string_sig;

   344   ciSymbol* int_sig;

   345   ciSymbol* char_sig;

   346   if (m->holder() == C->env()->StringBuilder_klass()) {

   347     string_sig = ciSymbol::String_StringBuilder_signature();

   348     int_sig = ciSymbol::int_StringBuilder_signature();

   349     char_sig = ciSymbol::char_StringBuilder_signature();

   350   } else if (m->holder() == C->env()->StringBuffer_klass()) {

   351     string_sig = ciSymbol::String_StringBuffer_signature();

   352     int_sig = ciSymbol::int_StringBuffer_signature();

   353     char_sig = ciSymbol::char_StringBuffer_signature();

   354   } else {

   355     return NULL;

   356   }

   357 #ifndef PRODUCT

   358   if (PrintOptimizeStringConcat) {

   359     tty->print("considering toString call in ");

   360     call->jvms()->dump_spec(tty); tty->cr();

   361   }

   362 #endif

   363 

   364   StringConcat* sc = new StringConcat(this, call);

   365 

   366   AllocateNode* alloc = NULL;

   367   InitializeNode* init = NULL;

   368 

   369   // possible opportunity for StringBuilder fusion

   370   CallStaticJavaNode* cnode = call;

   371   while (cnode) {

   372     Node* recv = cnode->in(TypeFunc::Parms)->uncast();

   373     if (recv->is_Proj()) {

   374       recv = recv->in(0);

   375     }

   376     cnode = recv->isa_CallStaticJava();

   377     if (cnode == NULL) {

   378       alloc = recv->isa_Allocate();

   379       if (alloc == NULL) {

   380         break;

   381       }

   382       // Find the constructor call

   383       Node* result = alloc->result_cast();

   384       if (result == NULL || !result->is_CheckCastPP()) {

   385         // strange looking allocation

   386 #ifndef PRODUCT

   387         if (PrintOptimizeStringConcat) {

   388           tty->print("giving up because allocation looks strange ");

   389           alloc->jvms()->dump_spec(tty); tty->cr();

   390         }

   391 #endif

   392         break;

   393       }

   394       Node* constructor = NULL;

   395       for (SimpleDUIterator i(result); i.has_next(); i.next()) {

   396         CallStaticJavaNode *use = i.get()->isa_CallStaticJava();

   397         if (use != NULL && use->method() != NULL &&

   398             use->method()->name() == ciSymbol::object_initializer_name() &&

   399             use->method()->holder() == m->holder()) {

   400           // Matched the constructor.

   401           ciSymbol* sig = use->method()->signature()->as_symbol();

   402           if (sig == ciSymbol::void_method_signature() ||

   403               sig == ciSymbol::int_void_signature() ||

   404               sig == ciSymbol::string_void_signature()) {

   405             if (sig == ciSymbol::string_void_signature()) {

   406               // StringBuilder(String) so pick this up as the first argument

   407               assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");

   408               sc->push_string(use->in(TypeFunc::Parms + 1));

   409             }

   410             // The int variant takes an initial size for the backing

   411             // array so just treat it like the void version.

   412             constructor = use;

   413           } else {

   414 #ifndef PRODUCT

   415             if (PrintOptimizeStringConcat) {

   416               tty->print("unexpected constructor signature: %s", sig->as_utf8());

   417             }

   418 #endif

   419           }

   420           break;

   421         }

   422       }

   423       if (constructor == NULL) {

   424         // couldn't find constructor

   425 #ifndef PRODUCT

   426         if (PrintOptimizeStringConcat) {

   427           tty->print("giving up because couldn't find constructor ");

   428           alloc->jvms()->dump_spec(tty);

   429         }

   430 #endif

   431         break;

   432       }

   433 

   434       // Walked all the way back and found the constructor call so see

   435       // if this call converted into a direct string concatenation.

   436       sc->add_control(call);

   437       sc->add_control(constructor);

   438       sc->add_control(alloc);

   439       sc->set_allocation(alloc);

   440       if (sc->validate_control_flow()) {

   441         return sc;

   442       } else {

   443         return NULL;

   444       }

   445     } else if (cnode->method() == NULL) {

   446       break;

   447     } else if (cnode->method()->holder() == m->holder() &&

   448                cnode->method()->name() == ciSymbol::append_name() &&

   449                (cnode->method()->signature()->as_symbol() == string_sig ||

   450                 cnode->method()->signature()->as_symbol() == char_sig ||

   451                 cnode->method()->signature()->as_symbol() == int_sig)) {

   452       sc->add_control(cnode);

   453       Node* arg = cnode->in(TypeFunc::Parms + 1);

   454       if (cnode->method()->signature()->as_symbol() == int_sig) {

   455         sc->push_int(arg);

   456       } else if (cnode->method()->signature()->as_symbol() == char_sig) {

   457         sc->push_char(arg);

   458       } else {

   459         if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {

   460           CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();

   461           if (csj->method() != NULL &&

   462               csj->method()->holder() == C->env()->Integer_klass() &&

   463               csj->method()->name() == ciSymbol::toString_name()) {

   464             sc->add_control(csj);

   465             sc->push_int(csj->in(TypeFunc::Parms));

   466             continue;

   467           }

   468         }

   469         sc->push_string(arg);

   470       }

   471       continue;

   472     } else {

   473       // some unhandled signature

   474 #ifndef PRODUCT

   475       if (PrintOptimizeStringConcat) {

   476         tty->print("giving up because encountered unexpected signature ");

   477         cnode->tf()->dump(); tty->cr();

   478         cnode->in(TypeFunc::Parms + 1)->dump();

   479       }

   480 #endif

   481       break;

   482     }

   483   }

   484   return NULL;

   485 }

   486 

   487 

   488 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):

   489   Phase(StringOpts),

   490   _gvn(gvn),

   491   _visited(Thread::current()->resource_area()) {

   492 

   493   assert(OptimizeStringConcat, "shouldn't be here");

   494 

   495   size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),

   496                                                                   ciSymbol::make("[I"), true);

   497   if (size_table_field == NULL) {

   498     // Something wrong so give up.

   499     assert(false, "why can't we find Integer.sizeTable?");

   500     return;

   501   }

   502 

   503   // Collect the types needed to talk about the various slices of memory

   504   const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),

   505                                                      false, NULL, 0);

   506 

   507   const TypePtr* value_field_type = string_type->add_offset(java_lang_String::value_offset_in_bytes());

   508   const TypePtr* offset_field_type = string_type->add_offset(java_lang_String::offset_offset_in_bytes());

   509   const TypePtr* count_field_type = string_type->add_offset(java_lang_String::count_offset_in_bytes());

   510 

   511   value_field_idx = C->get_alias_index(value_field_type);

   512   count_field_idx = C->get_alias_index(count_field_type);

   513   offset_field_idx = C->get_alias_index(offset_field_type);

   514   char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);

   515 

   516   // For each locally allocated StringBuffer see if the usages can be

   517   // collapsed into a single String construction.

   518 

   519   // Run through the list of allocation looking for SB.toString to see

   520   // if it's possible to fuse the usage of the SB into a single String

   521   // construction.

   522   GrowableArray<StringConcat*> concats;

   523   Node_List toStrings = collect_toString_calls();

   524   while (toStrings.size() > 0) {

   525     StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());

   526     if (sc != NULL) {

   527       concats.push(sc);

   528     }

   529   }

   530 

   531   // try to coalesce separate concats

   532  restart:

   533   for (int c = 0; c < concats.length(); c++) {

   534     StringConcat* sc = concats.at(c);

   535     for (int i = 0; i < sc->num_arguments(); i++) {

   536       Node* arg = sc->argument(i);

   537       if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {

   538         CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();

   539         if (csj->method() != NULL &&

   540             (csj->method()->holder() == C->env()->StringBuffer_klass() ||

   541              csj->method()->holder() == C->env()->StringBuilder_klass()) &&

   542             csj->method()->name() == ciSymbol::toString_name()) {

   543           for (int o = 0; o < concats.length(); o++) {

   544             if (c == o) continue;

   545             StringConcat* other = concats.at(o);

   546             if (other->end() == csj) {

   547 #ifndef PRODUCT

   548               if (PrintOptimizeStringConcat) {

   549                 tty->print_cr("considering stacked concats");

   550               }

   551 #endif

   552 

   553               StringConcat* merged = sc->merge(other, arg);

   554               if (merged->validate_control_flow()) {

   555 #ifndef PRODUCT

   556                 if (PrintOptimizeStringConcat) {

   557                   tty->print_cr("stacking would succeed");

   558                 }

   559 #endif

   560                 if (c < o) {

   561                   concats.remove_at(o);

   562                   concats.at_put(c, merged);

   563                 } else {

   564                   concats.remove_at(c);

   565                   concats.at_put(o, merged);

   566                 }

   567                 goto restart;

   568               } else {

   569 #ifndef PRODUCT

   570                 if (PrintOptimizeStringConcat) {

   571                   tty->print_cr("stacking would fail");

   572                 }

   573 #endif

   574               }

   575             }

   576           }

   577         }

   578       }

   579     }

   580   }

   581 

   582 

   583   for (int c = 0; c < concats.length(); c++) {

   584     StringConcat* sc = concats.at(c);

   585     replace_string_concat(sc);

   586   }

   587 

   588   remove_dead_nodes();

   589 }

   590 

   591 void PhaseStringOpts::record_dead_node(Node* dead) {

   592   dead_worklist.push(dead);

   593 }

   594 

   595 void PhaseStringOpts::remove_dead_nodes() {

   596   // Delete any dead nodes to make things clean enough that escape

   597   // analysis doesn't get unhappy.

   598   while (dead_worklist.size() > 0) {

   599     Node* use = dead_worklist.pop();

   600     int opc = use->Opcode();

   601     switch (opc) {

   602       case Op_Region: {

   603         uint i = 1;

   604         for (i = 1; i < use->req(); i++) {

   605           if (use->in(i) != C->top()) {

   606             break;

   607           }

   608         }

   609         if (i >= use->req()) {

   610           for (SimpleDUIterator i(use); i.has_next(); i.next()) {

   611             Node* m = i.get();

   612             if (m->is_Phi()) {

   613               dead_worklist.push(m);

   614             }

   615           }

   616           C->gvn_replace_by(use, C->top());

   617         }

   618         break;

   619       }

   620       case Op_AddP:

   621       case Op_CreateEx: {

   622         // Recurisvely clean up references to CreateEx so EA doesn't

   623         // get unhappy about the partially collapsed graph.

   624         for (SimpleDUIterator i(use); i.has_next(); i.next()) {

   625           Node* m = i.get();

   626           if (m->is_AddP()) {

   627             dead_worklist.push(m);

   628           }

   629         }

   630         C->gvn_replace_by(use, C->top());

   631         break;

   632       }

   633       case Op_Phi:

   634         if (use->in(0) == C->top()) {

   635           C->gvn_replace_by(use, C->top());

   636         }

   637         break;

   638     }

   639   }

   640 }

   641 

   642 

   643 bool StringConcat::validate_control_flow() {

   644   // We found all the calls and arguments now lets see if it's

   645   // safe to transform the graph as we would expect.

   646 

   647   // Check to see if this resulted in too many uncommon traps previously

   648   if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),

   649                         Deoptimization::Reason_intrinsic)) {

   650     return false;

   651   }

   652 

   653   // Walk backwards over the control flow from toString to the

   654   // allocation and make sure all the control flow is ok.  This

   655   // means it's either going to be eliminated once the calls are

   656   // removed or it can safely be transformed into an uncommon

   657   // trap.

   658 

   659   int null_check_count = 0;

   660   Unique_Node_List ctrl_path;

   661 

   662   assert(_control.contains(_begin), "missing");

   663   assert(_control.contains(_end), "missing");

   664 

   665   // Collect the nodes that we know about and will eliminate into ctrl_path

   666   for (uint i = 0; i < _control.size(); i++) {

   667     // Push the call and it's control projection

   668     Node* n = _control.at(i);

   669     if (n->is_Allocate()) {

   670       AllocateNode* an = n->as_Allocate();

   671       InitializeNode* init = an->initialization();

   672       ctrl_path.push(init);

   673       ctrl_path.push(init->as_Multi()->proj_out(0));

   674     }

   675     if (n->is_Call()) {

   676       CallNode* cn = n->as_Call();

   677       ctrl_path.push(cn);

   678       ctrl_path.push(cn->proj_out(0));

   679       ctrl_path.push(cn->proj_out(0)->unique_out());

   680       ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));

   681     } else {

   682       ShouldNotReachHere();

   683     }

   684   }

   685 

   686   // Skip backwards through the control checking for unexpected contro flow

   687   Node* ptr = _end;

   688   bool fail = false;

   689   while (ptr != _begin) {

   690     if (ptr->is_Call() && ctrl_path.member(ptr)) {

   691       ptr = ptr->in(0);

   692     } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {

   693       ptr = ptr->in(0)->in(0)->in(0);

   694       assert(ctrl_path.member(ptr), "should be a known piece of control");

   695     } else if (ptr->is_IfTrue()) {

   696       IfNode* iff = ptr->in(0)->as_If();

   697       BoolNode* b = iff->in(1)->isa_Bool();

   698       Node* cmp = b->in(1);

   699       Node* v1 = cmp->in(1);

   700       Node* v2 = cmp->in(2);

   701       Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);

   702 

   703       // Null check of the return of append which can simply be eliminated

   704       if (b->_test._test == BoolTest::ne &&

   705           v2->bottom_type() == TypePtr::NULL_PTR &&

   706           v1->is_Proj() && ctrl_path.member(v1->in(0))) {

   707         // NULL check of the return value of the append

   708         null_check_count++;

   709         if (otherproj->outcnt() == 1) {

   710           CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();

   711           if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {

   712             ctrl_path.push(call);

   713           }

   714         }

   715         _control.push(ptr);

   716         ptr = ptr->in(0)->in(0);

   717         continue;

   718       }

   719 

   720       // A test which leads to an uncommon trap which should be safe.

   721       // Later this trap will be converted into a trap that restarts

   722       // at the beginning.

   723       if (otherproj->outcnt() == 1) {

   724         CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();

   725         if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {

   726           // control flow leads to uct so should be ok

   727           _uncommon_traps.push(call);

   728           ctrl_path.push(call);

   729           ptr = ptr->in(0)->in(0);

   730           continue;

   731         }

   732       }

   733 

   734 #ifndef PRODUCT

   735       // Some unexpected control flow we don't know how to handle.

   736       if (PrintOptimizeStringConcat) {

   737         tty->print_cr("failing with unknown test");

   738         b->dump();

   739         cmp->dump();

   740         v1->dump();

   741         v2->dump();

   742         tty->cr();

   743       }

   744 #endif

   745       break;

   746     } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {

   747       ptr = ptr->in(0)->in(0);

   748     } else if (ptr->is_Region()) {

   749       Node* copy = ptr->as_Region()->is_copy();

   750       if (copy != NULL) {

   751         ptr = copy;

   752         continue;

   753       }

   754       if (ptr->req() == 3 &&

   755           ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&

   756           ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&

   757           ptr->in(1)->in(0) == ptr->in(2)->in(0) &&

   758           ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {

   759         // Simple diamond.

   760         // XXX should check for possibly merging stores.  simple data merges are ok.

   761         ptr = ptr->in(1)->in(0)->in(0);

   762         continue;

   763       }

   764 #ifndef PRODUCT

   765       if (PrintOptimizeStringConcat) {

   766         tty->print_cr("fusion would fail for region");

   767         _begin->dump();

   768         ptr->dump(2);

   769       }

   770 #endif

   771       fail = true;

   772       break;

   773     } else {

   774       // other unknown control

   775       if (!fail) {

   776 #ifndef PRODUCT

   777         if (PrintOptimizeStringConcat) {

   778           tty->print_cr("fusion would fail for");

   779           _begin->dump();

   780         }

   781 #endif

   782         fail = true;

   783       }

   784 #ifndef PRODUCT

   785       if (PrintOptimizeStringConcat) {

   786         ptr->dump();

   787       }

   788 #endif

   789       ptr = ptr->in(0);

   790     }

   791   }

   792 #ifndef PRODUCT

   793   if (PrintOptimizeStringConcat && fail) {

   794     tty->cr();

   795   }

   796 #endif

   797   if (fail) return !fail;

   798 

   799   // Validate that all these results produced are contained within

   800   // this cluster of objects.  First collect all the results produced

   801   // by calls in the region.

   802   _stringopts->_visited.Clear();

   803   Node_List worklist;

   804   Node* final_result = _end->proj_out(TypeFunc::Parms);

   805   for (uint i = 0; i < _control.size(); i++) {

   806     CallNode* cnode = _control.at(i)->isa_Call();

   807     if (cnode != NULL) {

   808       _stringopts->_visited.test_set(cnode->_idx);

   809     }

   810     Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;

   811     if (result != NULL && result != final_result) {

   812       worklist.push(result);

   813     }

   814   }

   815 

   816   Node* last_result = NULL;

   817   while (worklist.size() > 0) {

   818     Node* result = worklist.pop();

   819     if (_stringopts->_visited.test_set(result->_idx))

   820       continue;

   821     for (SimpleDUIterator i(result); i.has_next(); i.next()) {

   822       Node *use = i.get();

   823       if (ctrl_path.member(use)) {

   824         // already checked this

   825         continue;

   826       }

   827       int opc = use->Opcode();

   828       if (opc == Op_CmpP || opc == Op_Node) {

   829         ctrl_path.push(use);

   830         continue;

   831       }

   832       if (opc == Op_CastPP || opc == Op_CheckCastPP) {

   833         for (SimpleDUIterator j(use); j.has_next(); j.next()) {

   834           worklist.push(j.get());

   835         }

   836         worklist.push(use->in(1));

   837         ctrl_path.push(use);

   838         continue;

   839       }

   840 #ifndef PRODUCT

   841       if (PrintOptimizeStringConcat) {

   842         if (result != last_result) {

   843           last_result = result;

   844           tty->print_cr("extra uses for result:");

   845           last_result->dump();

   846         }

   847         use->dump();

   848       }

   849 #endif

   850       fail = true;

   851       break;

   852     }

   853   }

   854 

   855 #ifndef PRODUCT

   856   if (PrintOptimizeStringConcat && !fail) {

   857     ttyLocker ttyl;

   858     tty->cr();

   859     tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());

   860     _begin->jvms()->dump_spec(tty); tty->cr();

   861     for (int i = 0; i < num_arguments(); i++) {

   862       argument(i)->dump();

   863     }

   864     _control.dump();

   865     tty->cr();

   866   }

   867 #endif

   868 

   869   return !fail;

   870 }

   871 

   872 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {

   873   const TypeKlassPtr* klass_type = TypeKlassPtr::make(field->holder());

   874   Node* klass_node = __ makecon(klass_type);

   875   BasicType bt = field->layout_type();

   876   ciType* field_klass = field->type();

   877 

   878   const Type *type;

   879   if( bt == T_OBJECT ) {

   880     if (!field->type()->is_loaded()) {

   881       type = TypeInstPtr::BOTTOM;

   882     } else if (field->is_constant()) {

   883       // This can happen if the constant oop is non-perm.

   884       ciObject* con = field->constant_value().as_object();

   885       // Do not "join" in the previous type; it doesn't add value,

   886       // and may yield a vacuous result if the field is of interface type.

   887       type = TypeOopPtr::make_from_constant(con)->isa_oopptr();

   888       assert(type != NULL, "field singleton type must be consistent");

   889     } else {

   890       type = TypeOopPtr::make_from_klass(field_klass->as_klass());

   891     }

   892   } else {

   893     type = Type::get_const_basic_type(bt);

   894   }

   895 

   896   return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),

   897                        type, T_OBJECT,

   898                        C->get_alias_index(klass_type->add_offset(field->offset_in_bytes())));

   899 }

   900 

   901 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {

   902   RegionNode *final_merge = new (C, 3) RegionNode(3);

   903   kit.gvn().set_type(final_merge, Type::CONTROL);

   904   Node* final_size = new (C, 3) PhiNode(final_merge, TypeInt::INT);

   905   kit.gvn().set_type(final_size, TypeInt::INT);

   906 

   907   IfNode* iff = kit.create_and_map_if(kit.control(),

   908                                       __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),

   909                                       PROB_FAIR, COUNT_UNKNOWN);

   910   Node* is_min = __ IfFalse(iff);

   911   final_merge->init_req(1, is_min);

   912   final_size->init_req(1, __ intcon(11));

   913 

   914   kit.set_control(__ IfTrue(iff));

   915   if (kit.stopped()) {

   916     final_merge->init_req(2, C->top());

   917     final_size->init_req(2, C->top());

   918   } else {

   919 

   920     // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);

   921     RegionNode *r = new (C, 3) RegionNode(3);

   922     kit.gvn().set_type(r, Type::CONTROL);

   923     Node *phi = new (C, 3) PhiNode(r, TypeInt::INT);

   924     kit.gvn().set_type(phi, TypeInt::INT);

   925     Node *size = new (C, 3) PhiNode(r, TypeInt::INT);

   926     kit.gvn().set_type(size, TypeInt::INT);

   927     Node* chk = __ CmpI(arg, __ intcon(0));

   928     Node* p = __ Bool(chk, BoolTest::lt);

   929     IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);

   930     Node* lessthan = __ IfTrue(iff);

   931     Node* greaterequal = __ IfFalse(iff);

   932     r->init_req(1, lessthan);

   933     phi->init_req(1, __ SubI(__ intcon(0), arg));

   934     size->init_req(1, __ intcon(1));

   935     r->init_req(2, greaterequal);

   936     phi->init_req(2, arg);

   937     size->init_req(2, __ intcon(0));

   938     kit.set_control(r);

   939     C->record_for_igvn(r);

   940     C->record_for_igvn(phi);

   941     C->record_for_igvn(size);

   942 

   943     // for (int i=0; ; i++)

   944     //   if (x <= sizeTable[i])

   945     //     return i+1;

   946     RegionNode *loop = new (C, 3) RegionNode(3);

   947     loop->init_req(1, kit.control());

   948     kit.gvn().set_type(loop, Type::CONTROL);

   949 

   950     Node *index = new (C, 3) PhiNode(loop, TypeInt::INT);

   951     index->init_req(1, __ intcon(0));

   952     kit.gvn().set_type(index, TypeInt::INT);

   953     kit.set_control(loop);

   954     Node* sizeTable = fetch_static_field(kit, size_table_field);

   955 

   956     Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);

   957     C->record_for_igvn(value);

   958     Node* limit = __ CmpI(phi, value);

   959     Node* limitb = __ Bool(limit, BoolTest::le);

   960     IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);

   961     Node* lessEqual = __ IfTrue(iff2);

   962     Node* greater = __ IfFalse(iff2);

   963 

   964     loop->init_req(2, greater);

   965     index->init_req(2, __ AddI(index, __ intcon(1)));

   966 

   967     kit.set_control(lessEqual);

   968     C->record_for_igvn(loop);

   969     C->record_for_igvn(index);

   970 

   971     final_merge->init_req(2, kit.control());

   972     final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));

   973   }

   974 

   975   kit.set_control(final_merge);

   976   C->record_for_igvn(final_merge);

   977   C->record_for_igvn(final_size);

   978 

   979   return final_size;

   980 }

   981 

   982 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {

   983   RegionNode *final_merge = new (C, 4) RegionNode(4);

   984   kit.gvn().set_type(final_merge, Type::CONTROL);

   985   Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);

   986   kit.gvn().set_type(final_mem, Type::MEMORY);

   987 

   988   // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive

   989   {

   990     // i == MIN_VALUE

   991     IfNode* iff = kit.create_and_map_if(kit.control(),

   992                                         __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),

   993                                         PROB_FAIR, COUNT_UNKNOWN);

   994 

   995     Node* old_mem = kit.memory(char_adr_idx);

   996 

   997     kit.set_control(__ IfFalse(iff));

   998     if (kit.stopped()) {

   999       // Statically not equal to MIN_VALUE so this path is dead

  1000       final_merge->init_req(3, kit.control());

  1001     } else {

  1002       copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),

  1003                   char_array, start);

  1004       final_merge->init_req(3, kit.control());

  1005       final_mem->init_req(3, kit.memory(char_adr_idx));

  1006     }

  1007 

  1008     kit.set_control(__ IfTrue(iff));

  1009     kit.set_memory(old_mem, char_adr_idx);

  1010   }

  1011 

  1012 

  1013   // Simplified version of Integer.getChars

  1014 

  1015   // int q, r;

  1016   // int charPos = index;

  1017   Node* charPos = end;

  1018 

  1019   // char sign = 0;

  1020 

  1021   Node* i = arg;

  1022   Node* sign = __ intcon(0);

  1023 

  1024   // if (i < 0) {

  1025   //     sign = '-';

  1026   //     i = -i;

  1027   // }

  1028   {

  1029     IfNode* iff = kit.create_and_map_if(kit.control(),

  1030                                         __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),

  1031                                         PROB_FAIR, COUNT_UNKNOWN);

  1032 

  1033     RegionNode *merge = new (C, 3) RegionNode(3);

  1034     kit.gvn().set_type(merge, Type::CONTROL);

  1035     i = new (C, 3) PhiNode(merge, TypeInt::INT);

  1036     kit.gvn().set_type(i, TypeInt::INT);

  1037     sign = new (C, 3) PhiNode(merge, TypeInt::INT);

  1038     kit.gvn().set_type(sign, TypeInt::INT);

  1039 

  1040     merge->init_req(1, __ IfTrue(iff));

  1041     i->init_req(1, __ SubI(__ intcon(0), arg));

  1042     sign->init_req(1, __ intcon('-'));

  1043     merge->init_req(2, __ IfFalse(iff));

  1044     i->init_req(2, arg);

  1045     sign->init_req(2, __ intcon(0));

  1046 

  1047     kit.set_control(merge);

  1048 

  1049     C->record_for_igvn(merge);

  1050     C->record_for_igvn(i);

  1051     C->record_for_igvn(sign);

  1052   }

  1053 

  1054   // for (;;) {

  1055   //     q = i / 10;

  1056   //     r = i - ((q << 3) + (q << 1));  // r = i-(q*10) ...

  1057   //     buf [--charPos] = digits [r];

  1058   //     i = q;

  1059   //     if (i == 0) break;

  1060   // }

  1061 

  1062   {

  1063     RegionNode *head = new (C, 3) RegionNode(3);

  1064     head->init_req(1, kit.control());

  1065     kit.gvn().set_type(head, Type::CONTROL);

  1066     Node *i_phi = new (C, 3) PhiNode(head, TypeInt::INT);

  1067     i_phi->init_req(1, i);

  1068     kit.gvn().set_type(i_phi, TypeInt::INT);

  1069     charPos = PhiNode::make(head, charPos);

  1070     kit.gvn().set_type(charPos, TypeInt::INT);

  1071     Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);

  1072     kit.gvn().set_type(mem, Type::MEMORY);

  1073     kit.set_control(head);

  1074     kit.set_memory(mem, char_adr_idx);

  1075 

  1076     Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));

  1077     Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),

  1078                                      __ LShiftI(q, __ intcon(1))));

  1079     Node* m1 = __ SubI(charPos, __ intcon(1));

  1080     Node* ch = __ AddI(r, __ intcon('0'));

  1081 

  1082     Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),

  1083                                   ch, T_CHAR, char_adr_idx);

  1084 

  1085 

  1086     IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),

  1087                                         PROB_FAIR, COUNT_UNKNOWN);

  1088     Node* ne = __ IfTrue(iff);

  1089     Node* eq = __ IfFalse(iff);

  1090 

  1091     head->init_req(2, ne);

  1092     mem->init_req(2, st);

  1093     i_phi->init_req(2, q);

  1094     charPos->init_req(2, m1);

  1095 

  1096     charPos = m1;

  1097 

  1098     kit.set_control(eq);

  1099     kit.set_memory(st, char_adr_idx);

  1100 

  1101     C->record_for_igvn(head);

  1102     C->record_for_igvn(mem);

  1103     C->record_for_igvn(i_phi);

  1104     C->record_for_igvn(charPos);

  1105   }

  1106 

  1107   {

  1108     // if (sign != 0) {

  1109     //     buf [--charPos] = sign;

  1110     // }

  1111     IfNode* iff = kit.create_and_map_if(kit.control(),

  1112                                         __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),

  1113                                         PROB_FAIR, COUNT_UNKNOWN);

  1114 

  1115     final_merge->init_req(2, __ IfFalse(iff));

  1116     final_mem->init_req(2, kit.memory(char_adr_idx));

  1117 

  1118     kit.set_control(__ IfTrue(iff));

  1119     if (kit.stopped()) {

  1120       final_merge->init_req(1, C->top());

  1121       final_mem->init_req(1, C->top());

  1122     } else {

  1123       Node* m1 = __ SubI(charPos, __ intcon(1));

  1124       Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),

  1125                                     sign, T_CHAR, char_adr_idx);

  1126 

  1127       final_merge->init_req(1, kit.control());

  1128       final_mem->init_req(1, st);

  1129     }

  1130 

  1131     kit.set_control(final_merge);

  1132     kit.set_memory(final_mem, char_adr_idx);

  1133 

  1134     C->record_for_igvn(final_merge);

  1135     C->record_for_igvn(final_mem);