src/share/vm/opto/callnode.cpp

Fri, 16 Oct 2009 02:05:46 -0700

author
ysr
date
Fri, 16 Oct 2009 02:05:46 -0700
changeset 1462
39b01ab7035a
parent 1366
72088be4b386
child 1475
873ec3787992
permissions
-rw-r--r--

6888898: CMS: ReduceInitialCardMarks unsafe in the presence of cms precleaning
6889757: G1: enable card mark elision for initializing writes from compiled code (ReduceInitialCardMarks)
Summary: Defer the (compiler-elided) card-mark upon a slow-path allocation until after the store and before the next subsequent safepoint; G1 now answers yes to can_elide_tlab_write_barriers().
Reviewed-by: jcoomes, kvn, never

     1 /*
     2  * Copyright 1997-2009 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  */
    25 // Portions of code courtesy of Clifford Click
    27 // Optimization - Graph Style
    29 #include "incls/_precompiled.incl"
    30 #include "incls/_callnode.cpp.incl"
    32 //=============================================================================
    33 uint StartNode::size_of() const { return sizeof(*this); }
    34 uint StartNode::cmp( const Node &n ) const
    35 { return _domain == ((StartNode&)n)._domain; }
    36 const Type *StartNode::bottom_type() const { return _domain; }
    37 const Type *StartNode::Value(PhaseTransform *phase) const { return _domain; }
    38 #ifndef PRODUCT
    39 void StartNode::dump_spec(outputStream *st) const { st->print(" #"); _domain->dump_on(st);}
    40 #endif
    42 //------------------------------Ideal------------------------------------------
    43 Node *StartNode::Ideal(PhaseGVN *phase, bool can_reshape){
    44   return remove_dead_region(phase, can_reshape) ? this : NULL;
    45 }
    47 //------------------------------calling_convention-----------------------------
    48 void StartNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
    49   Matcher::calling_convention( sig_bt, parm_regs, argcnt, false );
    50 }
    52 //------------------------------Registers--------------------------------------
    53 const RegMask &StartNode::in_RegMask(uint) const {
    54   return RegMask::Empty;
    55 }
    57 //------------------------------match------------------------------------------
    58 // Construct projections for incoming parameters, and their RegMask info
    59 Node *StartNode::match( const ProjNode *proj, const Matcher *match ) {
    60   switch (proj->_con) {
    61   case TypeFunc::Control:
    62   case TypeFunc::I_O:
    63   case TypeFunc::Memory:
    64     return new (match->C, 1) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
    65   case TypeFunc::FramePtr:
    66     return new (match->C, 1) MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);
    67   case TypeFunc::ReturnAdr:
    68     return new (match->C, 1) MachProjNode(this,proj->_con,match->_return_addr_mask,Op_RegP);
    69   case TypeFunc::Parms:
    70   default: {
    71       uint parm_num = proj->_con - TypeFunc::Parms;
    72       const Type *t = _domain->field_at(proj->_con);
    73       if (t->base() == Type::Half)  // 2nd half of Longs and Doubles
    74         return new (match->C, 1) ConNode(Type::TOP);
    75       uint ideal_reg = Matcher::base2reg[t->base()];
    76       RegMask &rm = match->_calling_convention_mask[parm_num];
    77       return new (match->C, 1) MachProjNode(this,proj->_con,rm,ideal_reg);
    78     }
    79   }
    80   return NULL;
    81 }
    83 //------------------------------StartOSRNode----------------------------------
    84 // The method start node for an on stack replacement adapter
    86 //------------------------------osr_domain-----------------------------
    87 const TypeTuple *StartOSRNode::osr_domain() {
    88   const Type **fields = TypeTuple::fields(2);
    89   fields[TypeFunc::Parms+0] = TypeRawPtr::BOTTOM;  // address of osr buffer
    91   return TypeTuple::make(TypeFunc::Parms+1, fields);
    92 }
    94 //=============================================================================
    95 const char * const ParmNode::names[TypeFunc::Parms+1] = {
    96   "Control", "I_O", "Memory", "FramePtr", "ReturnAdr", "Parms"
    97 };
    99 #ifndef PRODUCT
   100 void ParmNode::dump_spec(outputStream *st) const {
   101   if( _con < TypeFunc::Parms ) {
   102     st->print(names[_con]);
   103   } else {
   104     st->print("Parm%d: ",_con-TypeFunc::Parms);
   105     // Verbose and WizardMode dump bottom_type for all nodes
   106     if( !Verbose && !WizardMode )   bottom_type()->dump_on(st);
   107   }
   108 }
   109 #endif
   111 uint ParmNode::ideal_reg() const {
   112   switch( _con ) {
   113   case TypeFunc::Control  : // fall through
   114   case TypeFunc::I_O      : // fall through
   115   case TypeFunc::Memory   : return 0;
   116   case TypeFunc::FramePtr : // fall through
   117   case TypeFunc::ReturnAdr: return Op_RegP;
   118   default                 : assert( _con > TypeFunc::Parms, "" );
   119     // fall through
   120   case TypeFunc::Parms    : {
   121     // Type of argument being passed
   122     const Type *t = in(0)->as_Start()->_domain->field_at(_con);
   123     return Matcher::base2reg[t->base()];
   124   }
   125   }
   126   ShouldNotReachHere();
   127   return 0;
   128 }
   130 //=============================================================================
   131 ReturnNode::ReturnNode(uint edges, Node *cntrl, Node *i_o, Node *memory, Node *frameptr, Node *retadr ) : Node(edges) {
   132   init_req(TypeFunc::Control,cntrl);
   133   init_req(TypeFunc::I_O,i_o);
   134   init_req(TypeFunc::Memory,memory);
   135   init_req(TypeFunc::FramePtr,frameptr);
   136   init_req(TypeFunc::ReturnAdr,retadr);
   137 }
   139 Node *ReturnNode::Ideal(PhaseGVN *phase, bool can_reshape){
   140   return remove_dead_region(phase, can_reshape) ? this : NULL;
   141 }
   143 const Type *ReturnNode::Value( PhaseTransform *phase ) const {
   144   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
   145     ? Type::TOP
   146     : Type::BOTTOM;
   147 }
   149 // Do we Match on this edge index or not?  No edges on return nodes
   150 uint ReturnNode::match_edge(uint idx) const {
   151   return 0;
   152 }
   155 #ifndef PRODUCT
   156 void ReturnNode::dump_req() const {
   157   // Dump the required inputs, enclosed in '(' and ')'
   158   uint i;                       // Exit value of loop
   159   for( i=0; i<req(); i++ ) {    // For all required inputs
   160     if( i == TypeFunc::Parms ) tty->print("returns");
   161     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
   162     else tty->print("_ ");
   163   }
   164 }
   165 #endif
   167 //=============================================================================
   168 RethrowNode::RethrowNode(
   169   Node* cntrl,
   170   Node* i_o,
   171   Node* memory,
   172   Node* frameptr,
   173   Node* ret_adr,
   174   Node* exception
   175 ) : Node(TypeFunc::Parms + 1) {
   176   init_req(TypeFunc::Control  , cntrl    );
   177   init_req(TypeFunc::I_O      , i_o      );
   178   init_req(TypeFunc::Memory   , memory   );
   179   init_req(TypeFunc::FramePtr , frameptr );
   180   init_req(TypeFunc::ReturnAdr, ret_adr);
   181   init_req(TypeFunc::Parms    , exception);
   182 }
   184 Node *RethrowNode::Ideal(PhaseGVN *phase, bool can_reshape){
   185   return remove_dead_region(phase, can_reshape) ? this : NULL;
   186 }
   188 const Type *RethrowNode::Value( PhaseTransform *phase ) const {
   189   return (phase->type(in(TypeFunc::Control)) == Type::TOP)
   190     ? Type::TOP
   191     : Type::BOTTOM;
   192 }
   194 uint RethrowNode::match_edge(uint idx) const {
   195   return 0;
   196 }
   198 #ifndef PRODUCT
   199 void RethrowNode::dump_req() const {
   200   // Dump the required inputs, enclosed in '(' and ')'
   201   uint i;                       // Exit value of loop
   202   for( i=0; i<req(); i++ ) {    // For all required inputs
   203     if( i == TypeFunc::Parms ) tty->print("exception");
   204     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
   205     else tty->print("_ ");
   206   }
   207 }
   208 #endif
   210 //=============================================================================
   211 // Do we Match on this edge index or not?  Match only target address & method
   212 uint TailCallNode::match_edge(uint idx) const {
   213   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
   214 }
   216 //=============================================================================
   217 // Do we Match on this edge index or not?  Match only target address & oop
   218 uint TailJumpNode::match_edge(uint idx) const {
   219   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
   220 }
   222 //=============================================================================
   223 JVMState::JVMState(ciMethod* method, JVMState* caller) {
   224   assert(method != NULL, "must be valid call site");
   225   _method = method;
   226   _reexecute = Reexecute_Undefined;
   227   debug_only(_bci = -99);  // random garbage value
   228   debug_only(_map = (SafePointNode*)-1);
   229   _caller = caller;
   230   _depth  = 1 + (caller == NULL ? 0 : caller->depth());
   231   _locoff = TypeFunc::Parms;
   232   _stkoff = _locoff + _method->max_locals();
   233   _monoff = _stkoff + _method->max_stack();
   234   _scloff = _monoff;
   235   _endoff = _monoff;
   236   _sp = 0;
   237 }
   238 JVMState::JVMState(int stack_size) {
   239   _method = NULL;
   240   _bci = InvocationEntryBci;
   241   _reexecute = Reexecute_Undefined;
   242   debug_only(_map = (SafePointNode*)-1);
   243   _caller = NULL;
   244   _depth  = 1;
   245   _locoff = TypeFunc::Parms;
   246   _stkoff = _locoff;
   247   _monoff = _stkoff + stack_size;
   248   _scloff = _monoff;
   249   _endoff = _monoff;
   250   _sp = 0;
   251 }
   253 //--------------------------------of_depth-------------------------------------
   254 JVMState* JVMState::of_depth(int d) const {
   255   const JVMState* jvmp = this;
   256   assert(0 < d && (uint)d <= depth(), "oob");
   257   for (int skip = depth() - d; skip > 0; skip--) {
   258     jvmp = jvmp->caller();
   259   }
   260   assert(jvmp->depth() == (uint)d, "found the right one");
   261   return (JVMState*)jvmp;
   262 }
   264 //-----------------------------same_calls_as-----------------------------------
   265 bool JVMState::same_calls_as(const JVMState* that) const {
   266   if (this == that)                    return true;
   267   if (this->depth() != that->depth())  return false;
   268   const JVMState* p = this;
   269   const JVMState* q = that;
   270   for (;;) {
   271     if (p->_method != q->_method)    return false;
   272     if (p->_method == NULL)          return true;   // bci is irrelevant
   273     if (p->_bci    != q->_bci)       return false;
   274     if (p->_reexecute != q->_reexecute)  return false;
   275     p = p->caller();
   276     q = q->caller();
   277     if (p == q)                      return true;
   278     assert(p != NULL && q != NULL, "depth check ensures we don't run off end");
   279   }
   280 }
   282 //------------------------------debug_start------------------------------------
   283 uint JVMState::debug_start()  const {
   284   debug_only(JVMState* jvmroot = of_depth(1));
   285   assert(jvmroot->locoff() <= this->locoff(), "youngest JVMState must be last");
   286   return of_depth(1)->locoff();
   287 }
   289 //-------------------------------debug_end-------------------------------------
   290 uint JVMState::debug_end() const {
   291   debug_only(JVMState* jvmroot = of_depth(1));
   292   assert(jvmroot->endoff() <= this->endoff(), "youngest JVMState must be last");
   293   return endoff();
   294 }
   296 //------------------------------debug_depth------------------------------------
   297 uint JVMState::debug_depth() const {
   298   uint total = 0;
   299   for (const JVMState* jvmp = this; jvmp != NULL; jvmp = jvmp->caller()) {
   300     total += jvmp->debug_size();
   301   }
   302   return total;
   303 }
   305 #ifndef PRODUCT
   307 //------------------------------format_helper----------------------------------
   308 // Given an allocation (a Chaitin object) and a Node decide if the Node carries
   309 // any defined value or not.  If it does, print out the register or constant.
   310 static void format_helper( PhaseRegAlloc *regalloc, outputStream* st, Node *n, const char *msg, uint i, GrowableArray<SafePointScalarObjectNode*> *scobjs ) {
   311   if (n == NULL) { st->print(" NULL"); return; }
   312   if (n->is_SafePointScalarObject()) {
   313     // Scalar replacement.
   314     SafePointScalarObjectNode* spobj = n->as_SafePointScalarObject();
   315     scobjs->append_if_missing(spobj);
   316     int sco_n = scobjs->find(spobj);
   317     assert(sco_n >= 0, "");
   318     st->print(" %s%d]=#ScObj" INT32_FORMAT, msg, i, sco_n);
   319     return;
   320   }
   321   if( OptoReg::is_valid(regalloc->get_reg_first(n))) { // Check for undefined
   322     char buf[50];
   323     regalloc->dump_register(n,buf);
   324     st->print(" %s%d]=%s",msg,i,buf);
   325   } else {                      // No register, but might be constant
   326     const Type *t = n->bottom_type();
   327     switch (t->base()) {
   328     case Type::Int:
   329       st->print(" %s%d]=#"INT32_FORMAT,msg,i,t->is_int()->get_con());
   330       break;
   331     case Type::AnyPtr:
   332       assert( t == TypePtr::NULL_PTR, "" );
   333       st->print(" %s%d]=#NULL",msg,i);
   334       break;
   335     case Type::AryPtr:
   336     case Type::KlassPtr:
   337     case Type::InstPtr:
   338       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->isa_oopptr()->const_oop());
   339       break;
   340     case Type::NarrowOop:
   341       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_oopptr()->const_oop());
   342       break;
   343     case Type::RawPtr:
   344       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,t->is_rawptr());
   345       break;
   346     case Type::DoubleCon:
   347       st->print(" %s%d]=#%fD",msg,i,t->is_double_constant()->_d);
   348       break;
   349     case Type::FloatCon:
   350       st->print(" %s%d]=#%fF",msg,i,t->is_float_constant()->_f);
   351       break;
   352     case Type::Long:
   353       st->print(" %s%d]=#"INT64_FORMAT,msg,i,t->is_long()->get_con());
   354       break;
   355     case Type::Half:
   356     case Type::Top:
   357       st->print(" %s%d]=_",msg,i);
   358       break;
   359     default: ShouldNotReachHere();
   360     }
   361   }
   362 }
   364 //------------------------------format-----------------------------------------
   365 void JVMState::format(PhaseRegAlloc *regalloc, const Node *n, outputStream* st) const {
   366   st->print("        #");
   367   if( _method ) {
   368     _method->print_short_name(st);
   369     st->print(" @ bci:%d ",_bci);
   370   } else {
   371     st->print_cr(" runtime stub ");
   372     return;
   373   }
   374   if (n->is_MachSafePoint()) {
   375     GrowableArray<SafePointScalarObjectNode*> scobjs;
   376     MachSafePointNode *mcall = n->as_MachSafePoint();
   377     uint i;
   378     // Print locals
   379     for( i = 0; i < (uint)loc_size(); i++ )
   380       format_helper( regalloc, st, mcall->local(this, i), "L[", i, &scobjs );
   381     // Print stack
   382     for (i = 0; i < (uint)stk_size(); i++) {
   383       if ((uint)(_stkoff + i) >= mcall->len())
   384         st->print(" oob ");
   385       else
   386        format_helper( regalloc, st, mcall->stack(this, i), "STK[", i, &scobjs );
   387     }
   388     for (i = 0; (int)i < nof_monitors(); i++) {
   389       Node *box = mcall->monitor_box(this, i);
   390       Node *obj = mcall->monitor_obj(this, i);
   391       if ( OptoReg::is_valid(regalloc->get_reg_first(box)) ) {
   392         while( !box->is_BoxLock() )  box = box->in(1);
   393         format_helper( regalloc, st, box, "MON-BOX[", i, &scobjs );
   394       } else {
   395         OptoReg::Name box_reg = BoxLockNode::stack_slot(box);
   396         st->print(" MON-BOX%d=%s+%d",
   397                    i,
   398                    OptoReg::regname(OptoReg::c_frame_pointer),
   399                    regalloc->reg2offset(box_reg));
   400       }
   401       const char* obj_msg = "MON-OBJ[";
   402       if (EliminateLocks) {
   403         while( !box->is_BoxLock() )  box = box->in(1);
   404         if (box->as_BoxLock()->is_eliminated())
   405           obj_msg = "MON-OBJ(LOCK ELIMINATED)[";
   406       }
   407       format_helper( regalloc, st, obj, obj_msg, i, &scobjs );
   408     }
   410     for (i = 0; i < (uint)scobjs.length(); i++) {
   411       // Scalar replaced objects.
   412       st->print_cr("");
   413       st->print("        # ScObj" INT32_FORMAT " ", i);
   414       SafePointScalarObjectNode* spobj = scobjs.at(i);
   415       ciKlass* cik = spobj->bottom_type()->is_oopptr()->klass();
   416       assert(cik->is_instance_klass() ||
   417              cik->is_array_klass(), "Not supported allocation.");
   418       ciInstanceKlass *iklass = NULL;
   419       if (cik->is_instance_klass()) {
   420         cik->print_name_on(st);
   421         iklass = cik->as_instance_klass();
   422       } else if (cik->is_type_array_klass()) {
   423         cik->as_array_klass()->base_element_type()->print_name_on(st);
   424         st->print("[%d]=", spobj->n_fields());
   425       } else if (cik->is_obj_array_klass()) {
   426         ciType* cie = cik->as_array_klass()->base_element_type();
   427         int ndim = 1;
   428         while (cie->is_obj_array_klass()) {
   429           ndim += 1;
   430           cie = cie->as_array_klass()->base_element_type();
   431         }
   432         cie->print_name_on(st);
   433         while (ndim-- > 0) {
   434           st->print("[]");
   435         }
   436         st->print("[%d]=", spobj->n_fields());
   437       }
   438       st->print("{");
   439       uint nf = spobj->n_fields();
   440       if (nf > 0) {
   441         uint first_ind = spobj->first_index();
   442         Node* fld_node = mcall->in(first_ind);
   443         ciField* cifield;
   444         if (iklass != NULL) {
   445           st->print(" [");
   446           cifield = iklass->nonstatic_field_at(0);
   447           cifield->print_name_on(st);
   448           format_helper( regalloc, st, fld_node, ":", 0, &scobjs );
   449         } else {
   450           format_helper( regalloc, st, fld_node, "[", 0, &scobjs );
   451         }
   452         for (uint j = 1; j < nf; j++) {
   453           fld_node = mcall->in(first_ind+j);
   454           if (iklass != NULL) {
   455             st->print(", [");
   456             cifield = iklass->nonstatic_field_at(j);
   457             cifield->print_name_on(st);
   458             format_helper( regalloc, st, fld_node, ":", j, &scobjs );
   459           } else {
   460             format_helper( regalloc, st, fld_node, ", [", j, &scobjs );
   461           }
   462         }
   463       }
   464       st->print(" }");
   465     }
   466   }
   467   st->print_cr("");
   468   if (caller() != NULL)  caller()->format(regalloc, n, st);
   469 }
   472 void JVMState::dump_spec(outputStream *st) const {
   473   if (_method != NULL) {
   474     bool printed = false;
   475     if (!Verbose) {
   476       // The JVMS dumps make really, really long lines.
   477       // Take out the most boring parts, which are the package prefixes.
   478       char buf[500];
   479       stringStream namest(buf, sizeof(buf));
   480       _method->print_short_name(&namest);
   481       if (namest.count() < sizeof(buf)) {
   482         const char* name = namest.base();
   483         if (name[0] == ' ')  ++name;
   484         const char* endcn = strchr(name, ':');  // end of class name
   485         if (endcn == NULL)  endcn = strchr(name, '(');
   486         if (endcn == NULL)  endcn = name + strlen(name);
   487         while (endcn > name && endcn[-1] != '.' && endcn[-1] != '/')
   488           --endcn;
   489         st->print(" %s", endcn);
   490         printed = true;
   491       }
   492     }
   493     if (!printed)
   494       _method->print_short_name(st);
   495     st->print(" @ bci:%d",_bci);
   496     if(_reexecute == Reexecute_True)
   497       st->print(" reexecute");
   498   } else {
   499     st->print(" runtime stub");
   500   }
   501   if (caller() != NULL)  caller()->dump_spec(st);
   502 }
   505 void JVMState::dump_on(outputStream* st) const {
   506   if (_map && !((uintptr_t)_map & 1)) {
   507     if (_map->len() > _map->req()) {  // _map->has_exceptions()
   508       Node* ex = _map->in(_map->req());  // _map->next_exception()
   509       // skip the first one; it's already being printed
   510       while (ex != NULL && ex->len() > ex->req()) {
   511         ex = ex->in(ex->req());  // ex->next_exception()
   512         ex->dump(1);
   513       }
   514     }
   515     _map->dump(2);
   516   }
   517   st->print("JVMS depth=%d loc=%d stk=%d mon=%d scalar=%d end=%d mondepth=%d sp=%d bci=%d reexecute=%s method=",
   518              depth(), locoff(), stkoff(), monoff(), scloff(), endoff(), monitor_depth(), sp(), bci(), should_reexecute()?"true":"false");
   519   if (_method == NULL) {
   520     st->print_cr("(none)");
   521   } else {
   522     _method->print_name(st);
   523     st->cr();
   524     if (bci() >= 0 && bci() < _method->code_size()) {
   525       st->print("    bc: ");
   526       _method->print_codes_on(bci(), bci()+1, st);
   527     }
   528   }
   529   if (caller() != NULL) {
   530     caller()->dump_on(st);
   531   }
   532 }
   534 // Extra way to dump a jvms from the debugger,
   535 // to avoid a bug with C++ member function calls.
   536 void dump_jvms(JVMState* jvms) {
   537   jvms->dump();
   538 }
   539 #endif
   541 //--------------------------clone_shallow--------------------------------------
   542 JVMState* JVMState::clone_shallow(Compile* C) const {
   543   JVMState* n = has_method() ? new (C) JVMState(_method, _caller) : new (C) JVMState(0);
   544   n->set_bci(_bci);
   545   n->_reexecute = _reexecute;
   546   n->set_locoff(_locoff);
   547   n->set_stkoff(_stkoff);
   548   n->set_monoff(_monoff);
   549   n->set_scloff(_scloff);
   550   n->set_endoff(_endoff);
   551   n->set_sp(_sp);
   552   n->set_map(_map);
   553   return n;
   554 }
   556 //---------------------------clone_deep----------------------------------------
   557 JVMState* JVMState::clone_deep(Compile* C) const {
   558   JVMState* n = clone_shallow(C);
   559   for (JVMState* p = n; p->_caller != NULL; p = p->_caller) {
   560     p->_caller = p->_caller->clone_shallow(C);
   561   }
   562   assert(n->depth() == depth(), "sanity");
   563   assert(n->debug_depth() == debug_depth(), "sanity");
   564   return n;
   565 }
   567 //=============================================================================
   568 uint CallNode::cmp( const Node &n ) const
   569 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }
   570 #ifndef PRODUCT
   571 void CallNode::dump_req() const {
   572   // Dump the required inputs, enclosed in '(' and ')'
   573   uint i;                       // Exit value of loop
   574   for( i=0; i<req(); i++ ) {    // For all required inputs
   575     if( i == TypeFunc::Parms ) tty->print("(");
   576     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
   577     else tty->print("_ ");
   578   }
   579   tty->print(")");
   580 }
   582 void CallNode::dump_spec(outputStream *st) const {
   583   st->print(" ");
   584   tf()->dump_on(st);
   585   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);
   586   if (jvms() != NULL)  jvms()->dump_spec(st);
   587 }
   588 #endif
   590 const Type *CallNode::bottom_type() const { return tf()->range(); }
   591 const Type *CallNode::Value(PhaseTransform *phase) const {
   592   if (phase->type(in(0)) == Type::TOP)  return Type::TOP;
   593   return tf()->range();
   594 }
   596 //------------------------------calling_convention-----------------------------
   597 void CallNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
   598   // Use the standard compiler calling convention
   599   Matcher::calling_convention( sig_bt, parm_regs, argcnt, true );
   600 }
   603 //------------------------------match------------------------------------------
   604 // Construct projections for control, I/O, memory-fields, ..., and
   605 // return result(s) along with their RegMask info
   606 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {
   607   switch (proj->_con) {
   608   case TypeFunc::Control:
   609   case TypeFunc::I_O:
   610   case TypeFunc::Memory:
   611     return new (match->C, 1) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
   613   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns
   614     assert(tf()->_range->field_at(TypeFunc::Parms+1) == Type::HALF, "");
   615     // 2nd half of doubles and longs
   616     return new (match->C, 1) MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);
   618   case TypeFunc::Parms: {       // Normal returns
   619     uint ideal_reg = Matcher::base2reg[tf()->range()->field_at(TypeFunc::Parms)->base()];
   620     OptoRegPair regs = is_CallRuntime()
   621       ? match->c_return_value(ideal_reg,true)  // Calls into C runtime
   622       : match->  return_value(ideal_reg,true); // Calls into compiled Java code
   623     RegMask rm = RegMask(regs.first());
   624     if( OptoReg::is_valid(regs.second()) )
   625       rm.Insert( regs.second() );
   626     return new (match->C, 1) MachProjNode(this,proj->_con,rm,ideal_reg);
   627   }
   629   case TypeFunc::ReturnAdr:
   630   case TypeFunc::FramePtr:
   631   default:
   632     ShouldNotReachHere();
   633   }
   634   return NULL;
   635 }
   637 // Do we Match on this edge index or not?  Match no edges
   638 uint CallNode::match_edge(uint idx) const {
   639   return 0;
   640 }
   642 //
   643 // Determine whether the call could modify the field of the specified
   644 // instance at the specified offset.
   645 //
   646 bool CallNode::may_modify(const TypePtr *addr_t, PhaseTransform *phase) {
   647   const TypeOopPtr *adrInst_t  = addr_t->isa_oopptr();
   649   // If not an OopPtr or not an instance type, assume the worst.
   650   // Note: currently this method is called only for instance types.
   651   if (adrInst_t == NULL || !adrInst_t->is_known_instance()) {
   652     return true;
   653   }
   654   // The instance_id is set only for scalar-replaceable allocations which
   655   // are not passed as arguments according to Escape Analysis.
   656   return false;
   657 }
   659 // Does this call have a direct reference to n other than debug information?
   660 bool CallNode::has_non_debug_use(Node *n) {
   661   const TypeTuple * d = tf()->domain();
   662   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
   663     Node *arg = in(i);
   664     if (arg == n) {
   665       return true;
   666     }
   667   }
   668   return false;
   669 }
   671 // Returns the unique CheckCastPP of a call
   672 // or 'this' if there are several CheckCastPP
   673 // or returns NULL if there is no one.
   674 Node *CallNode::result_cast() {
   675   Node *cast = NULL;
   677   Node *p = proj_out(TypeFunc::Parms);
   678   if (p == NULL)
   679     return NULL;
   681   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {
   682     Node *use = p->fast_out(i);
   683     if (use->is_CheckCastPP()) {
   684       if (cast != NULL) {
   685         return this;  // more than 1 CheckCastPP
   686       }
   687       cast = use;
   688     }
   689   }
   690   return cast;
   691 }
   694 //=============================================================================
   695 uint CallJavaNode::size_of() const { return sizeof(*this); }
   696 uint CallJavaNode::cmp( const Node &n ) const {
   697   CallJavaNode &call = (CallJavaNode&)n;
   698   return CallNode::cmp(call) && _method == call._method;
   699 }
   700 #ifndef PRODUCT
   701 void CallJavaNode::dump_spec(outputStream *st) const {
   702   if( _method ) _method->print_short_name(st);
   703   CallNode::dump_spec(st);
   704 }
   705 #endif
   707 //=============================================================================
   708 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }
   709 uint CallStaticJavaNode::cmp( const Node &n ) const {
   710   CallStaticJavaNode &call = (CallStaticJavaNode&)n;
   711   return CallJavaNode::cmp(call);
   712 }
   714 //----------------------------uncommon_trap_request----------------------------
   715 // If this is an uncommon trap, return the request code, else zero.
   716 int CallStaticJavaNode::uncommon_trap_request() const {
   717   if (_name != NULL && !strcmp(_name, "uncommon_trap")) {
   718     return extract_uncommon_trap_request(this);
   719   }
   720   return 0;
   721 }
   722 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {
   723 #ifndef PRODUCT
   724   if (!(call->req() > TypeFunc::Parms &&
   725         call->in(TypeFunc::Parms) != NULL &&
   726         call->in(TypeFunc::Parms)->is_Con())) {
   727     assert(_in_dump_cnt != 0, "OK if dumping");
   728     tty->print("[bad uncommon trap]");
   729     return 0;
   730   }
   731 #endif
   732   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();
   733 }
   735 #ifndef PRODUCT
   736 void CallStaticJavaNode::dump_spec(outputStream *st) const {
   737   st->print("# Static ");
   738   if (_name != NULL) {
   739     st->print("%s", _name);
   740     int trap_req = uncommon_trap_request();
   741     if (trap_req != 0) {
   742       char buf[100];
   743       st->print("(%s)",
   744                  Deoptimization::format_trap_request(buf, sizeof(buf),
   745                                                      trap_req));
   746     }
   747     st->print(" ");
   748   }
   749   CallJavaNode::dump_spec(st);
   750 }
   751 #endif
   753 //=============================================================================
   754 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }
   755 uint CallDynamicJavaNode::cmp( const Node &n ) const {
   756   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;
   757   return CallJavaNode::cmp(call);
   758 }
   759 #ifndef PRODUCT
   760 void CallDynamicJavaNode::dump_spec(outputStream *st) const {
   761   st->print("# Dynamic ");
   762   CallJavaNode::dump_spec(st);
   763 }
   764 #endif
   766 //=============================================================================
   767 uint CallRuntimeNode::size_of() const { return sizeof(*this); }
   768 uint CallRuntimeNode::cmp( const Node &n ) const {
   769   CallRuntimeNode &call = (CallRuntimeNode&)n;
   770   return CallNode::cmp(call) && !strcmp(_name,call._name);
   771 }
   772 #ifndef PRODUCT
   773 void CallRuntimeNode::dump_spec(outputStream *st) const {
   774   st->print("# ");
   775   st->print(_name);
   776   CallNode::dump_spec(st);
   777 }
   778 #endif
   780 //------------------------------calling_convention-----------------------------
   781 void CallRuntimeNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
   782   Matcher::c_calling_convention( sig_bt, parm_regs, argcnt );
   783 }
   785 //=============================================================================
   786 //------------------------------calling_convention-----------------------------
   789 //=============================================================================
   790 #ifndef PRODUCT
   791 void CallLeafNode::dump_spec(outputStream *st) const {
   792   st->print("# ");
   793   st->print(_name);
   794   CallNode::dump_spec(st);
   795 }
   796 #endif
   798 //=============================================================================
   800 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {
   801   assert(verify_jvms(jvms), "jvms must match");
   802   int loc = jvms->locoff() + idx;
   803   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {
   804     // If current local idx is top then local idx - 1 could
   805     // be a long/double that needs to be killed since top could
   806     // represent the 2nd half ofthe long/double.
   807     uint ideal = in(loc -1)->ideal_reg();
   808     if (ideal == Op_RegD || ideal == Op_RegL) {
   809       // set other (low index) half to top
   810       set_req(loc - 1, in(loc));
   811     }
   812   }
   813   set_req(loc, c);
   814 }
   816 uint SafePointNode::size_of() const { return sizeof(*this); }
   817 uint SafePointNode::cmp( const Node &n ) const {
   818   return (&n == this);          // Always fail except on self
   819 }
   821 //-------------------------set_next_exception----------------------------------
   822 void SafePointNode::set_next_exception(SafePointNode* n) {
   823   assert(n == NULL || n->Opcode() == Op_SafePoint, "correct value for next_exception");
   824   if (len() == req()) {
   825     if (n != NULL)  add_prec(n);
   826   } else {
   827     set_prec(req(), n);
   828   }
   829 }
   832 //----------------------------next_exception-----------------------------------
   833 SafePointNode* SafePointNode::next_exception() const {
   834   if (len() == req()) {
   835     return NULL;
   836   } else {
   837     Node* n = in(req());
   838     assert(n == NULL || n->Opcode() == Op_SafePoint, "no other uses of prec edges");
   839     return (SafePointNode*) n;
   840   }
   841 }
   844 //------------------------------Ideal------------------------------------------
   845 // Skip over any collapsed Regions
   846 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   847   return remove_dead_region(phase, can_reshape) ? this : NULL;
   848 }
   850 //------------------------------Identity---------------------------------------
   851 // Remove obviously duplicate safepoints
   852 Node *SafePointNode::Identity( PhaseTransform *phase ) {
   854   // If you have back to back safepoints, remove one
   855   if( in(TypeFunc::Control)->is_SafePoint() )
   856     return in(TypeFunc::Control);
   858   if( in(0)->is_Proj() ) {
   859     Node *n0 = in(0)->in(0);
   860     // Check if he is a call projection (except Leaf Call)
   861     if( n0->is_Catch() ) {
   862       n0 = n0->in(0)->in(0);
   863       assert( n0->is_Call(), "expect a call here" );
   864     }
   865     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {
   866       // Useless Safepoint, so remove it
   867       return in(TypeFunc::Control);
   868     }
   869   }
   871   return this;
   872 }
   874 //------------------------------Value------------------------------------------
   875 const Type *SafePointNode::Value( PhaseTransform *phase ) const {
   876   if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
   877   if( phase->eqv( in(0), this ) ) return Type::TOP; // Dead infinite loop
   878   return Type::CONTROL;
   879 }
   881 #ifndef PRODUCT
   882 void SafePointNode::dump_spec(outputStream *st) const {
   883   st->print(" SafePoint ");
   884 }
   885 #endif
   887 const RegMask &SafePointNode::in_RegMask(uint idx) const {
   888   if( idx < TypeFunc::Parms ) return RegMask::Empty;
   889   // Values outside the domain represent debug info
   890   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
   891 }
   892 const RegMask &SafePointNode::out_RegMask() const {
   893   return RegMask::Empty;
   894 }
   897 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {
   898   assert((int)grow_by > 0, "sanity");
   899   int monoff = jvms->monoff();
   900   int scloff = jvms->scloff();
   901   int endoff = jvms->endoff();
   902   assert(endoff == (int)req(), "no other states or debug info after me");
   903   Node* top = Compile::current()->top();
   904   for (uint i = 0; i < grow_by; i++) {
   905     ins_req(monoff, top);
   906   }
   907   jvms->set_monoff(monoff + grow_by);
   908   jvms->set_scloff(scloff + grow_by);
   909   jvms->set_endoff(endoff + grow_by);
   910 }
   912 void SafePointNode::push_monitor(const FastLockNode *lock) {
   913   // Add a LockNode, which points to both the original BoxLockNode (the
   914   // stack space for the monitor) and the Object being locked.
   915   const int MonitorEdges = 2;
   916   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
   917   assert(req() == jvms()->endoff(), "correct sizing");
   918   int nextmon = jvms()->scloff();
   919   if (GenerateSynchronizationCode) {
   920     add_req(lock->box_node());
   921     add_req(lock->obj_node());
   922   } else {
   923     Node* top = Compile::current()->top();
   924     add_req(top);
   925     add_req(top);
   926   }
   927   jvms()->set_scloff(nextmon+MonitorEdges);
   928   jvms()->set_endoff(req());
   929 }
   931 void SafePointNode::pop_monitor() {
   932   // Delete last monitor from debug info
   933   debug_only(int num_before_pop = jvms()->nof_monitors());
   934   const int MonitorEdges = (1<<JVMState::logMonitorEdges);
   935   int scloff = jvms()->scloff();
   936   int endoff = jvms()->endoff();
   937   int new_scloff = scloff - MonitorEdges;
   938   int new_endoff = endoff - MonitorEdges;
   939   jvms()->set_scloff(new_scloff);
   940   jvms()->set_endoff(new_endoff);
   941   while (scloff > new_scloff)  del_req(--scloff);
   942   assert(jvms()->nof_monitors() == num_before_pop-1, "");
   943 }
   945 Node *SafePointNode::peek_monitor_box() const {
   946   int mon = jvms()->nof_monitors() - 1;
   947   assert(mon >= 0, "most have a monitor");
   948   return monitor_box(jvms(), mon);
   949 }
   951 Node *SafePointNode::peek_monitor_obj() const {
   952   int mon = jvms()->nof_monitors() - 1;
   953   assert(mon >= 0, "most have a monitor");
   954   return monitor_obj(jvms(), mon);
   955 }
   957 // Do we Match on this edge index or not?  Match no edges
   958 uint SafePointNode::match_edge(uint idx) const {
   959   if( !needs_polling_address_input() )
   960     return 0;
   962   return (TypeFunc::Parms == idx);
   963 }
   965 //==============  SafePointScalarObjectNode  ==============
   967 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp,
   968 #ifdef ASSERT
   969                                                      AllocateNode* alloc,
   970 #endif
   971                                                      uint first_index,
   972                                                      uint n_fields) :
   973   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
   974 #ifdef ASSERT
   975   _alloc(alloc),
   976 #endif
   977   _first_index(first_index),
   978   _n_fields(n_fields)
   979 {
   980   init_class_id(Class_SafePointScalarObject);
   981 }
   983 bool SafePointScalarObjectNode::pinned() const { return true; }
   984 bool SafePointScalarObjectNode::depends_only_on_test() const { return false; }
   986 uint SafePointScalarObjectNode::ideal_reg() const {
   987   return 0; // No matching to machine instruction
   988 }
   990 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {
   991   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
   992 }
   994 const RegMask &SafePointScalarObjectNode::out_RegMask() const {
   995   return RegMask::Empty;
   996 }
   998 uint SafePointScalarObjectNode::match_edge(uint idx) const {
   999   return 0;
  1002 SafePointScalarObjectNode*
  1003 SafePointScalarObjectNode::clone(int jvms_adj, Dict* sosn_map) const {
  1004   void* cached = (*sosn_map)[(void*)this];
  1005   if (cached != NULL) {
  1006     return (SafePointScalarObjectNode*)cached;
  1008   Compile* C = Compile::current();
  1009   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();
  1010   res->_first_index += jvms_adj;
  1011   sosn_map->Insert((void*)this, (void*)res);
  1012   return res;
  1016 #ifndef PRODUCT
  1017 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {
  1018   st->print(" # fields@[%d..%d]", first_index(),
  1019              first_index() + n_fields() - 1);
  1022 #endif
  1024 //=============================================================================
  1025 uint AllocateNode::size_of() const { return sizeof(*this); }
  1027 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,
  1028                            Node *ctrl, Node *mem, Node *abio,
  1029                            Node *size, Node *klass_node, Node *initial_test)
  1030   : CallNode(atype, NULL, TypeRawPtr::BOTTOM)
  1032   init_class_id(Class_Allocate);
  1033   init_flags(Flag_is_macro);
  1034   _is_scalar_replaceable = false;
  1035   Node *topnode = C->top();
  1037   init_req( TypeFunc::Control  , ctrl );
  1038   init_req( TypeFunc::I_O      , abio );
  1039   init_req( TypeFunc::Memory   , mem );
  1040   init_req( TypeFunc::ReturnAdr, topnode );
  1041   init_req( TypeFunc::FramePtr , topnode );
  1042   init_req( AllocSize          , size);
  1043   init_req( KlassNode          , klass_node);
  1044   init_req( InitialTest        , initial_test);
  1045   init_req( ALength            , topnode);
  1046   C->add_macro_node(this);
  1049 //=============================================================================
  1050 uint AllocateArrayNode::size_of() const { return sizeof(*this); }
  1052 Node* AllocateArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  1053   if (remove_dead_region(phase, can_reshape))  return this;
  1055   const Type* type = phase->type(Ideal_length());
  1056   if (type->isa_int() && type->is_int()->_hi < 0) {
  1057     if (can_reshape) {
  1058       PhaseIterGVN *igvn = phase->is_IterGVN();
  1059       // Unreachable fall through path (negative array length),
  1060       // the allocation can only throw so disconnect it.
  1061       Node* proj = proj_out(TypeFunc::Control);
  1062       Node* catchproj = NULL;
  1063       if (proj != NULL) {
  1064         for (DUIterator_Fast imax, i = proj->fast_outs(imax); i < imax; i++) {
  1065           Node *cn = proj->fast_out(i);
  1066           if (cn->is_Catch()) {
  1067             catchproj = cn->as_Multi()->proj_out(CatchProjNode::fall_through_index);
  1068             break;
  1072       if (catchproj != NULL && catchproj->outcnt() > 0 &&
  1073           (catchproj->outcnt() > 1 ||
  1074            catchproj->unique_out()->Opcode() != Op_Halt)) {
  1075         assert(catchproj->is_CatchProj(), "must be a CatchProjNode");
  1076         Node* nproj = catchproj->clone();
  1077         igvn->register_new_node_with_optimizer(nproj);
  1079         Node *frame = new (phase->C, 1) ParmNode( phase->C->start(), TypeFunc::FramePtr );
  1080         frame = phase->transform(frame);
  1081         // Halt & Catch Fire
  1082         Node *halt = new (phase->C, TypeFunc::Parms) HaltNode( nproj, frame );
  1083         phase->C->root()->add_req(halt);
  1084         phase->transform(halt);
  1086         igvn->replace_node(catchproj, phase->C->top());
  1087         return this;
  1089     } else {
  1090       // Can't correct it during regular GVN so register for IGVN
  1091       phase->C->record_for_igvn(this);
  1094   return NULL;
  1097 // Retrieve the length from the AllocateArrayNode. Narrow the type with a
  1098 // CastII, if appropriate.  If we are not allowed to create new nodes, and
  1099 // a CastII is appropriate, return NULL.
  1100 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseTransform *phase, bool allow_new_nodes) {
  1101   Node *length = in(AllocateNode::ALength);
  1102   assert(length != NULL, "length is not null");
  1104   const TypeInt* length_type = phase->find_int_type(length);
  1105   const TypeAryPtr* ary_type = oop_type->isa_aryptr();
  1107   if (ary_type != NULL && length_type != NULL) {
  1108     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);
  1109     if (narrow_length_type != length_type) {
  1110       // Assert one of:
  1111       //   - the narrow_length is 0
  1112       //   - the narrow_length is not wider than length
  1113       assert(narrow_length_type == TypeInt::ZERO ||
  1114              (narrow_length_type->_hi <= length_type->_hi &&
  1115               narrow_length_type->_lo >= length_type->_lo),
  1116              "narrow type must be narrower than length type");
  1118       // Return NULL if new nodes are not allowed
  1119       if (!allow_new_nodes) return NULL;
  1120       // Create a cast which is control dependent on the initialization to
  1121       // propagate the fact that the array length must be positive.
  1122       length = new (phase->C, 2) CastIINode(length, narrow_length_type);
  1123       length->set_req(0, initialization()->proj_out(0));
  1127   return length;
  1130 //=============================================================================
  1131 uint LockNode::size_of() const { return sizeof(*this); }
  1133 // Redundant lock elimination
  1134 //
  1135 // There are various patterns of locking where we release and
  1136 // immediately reacquire a lock in a piece of code where no operations
  1137 // occur in between that would be observable.  In those cases we can
  1138 // skip releasing and reacquiring the lock without violating any
  1139 // fairness requirements.  Doing this around a loop could cause a lock
  1140 // to be held for a very long time so we concentrate on non-looping
  1141 // control flow.  We also require that the operations are fully
  1142 // redundant meaning that we don't introduce new lock operations on
  1143 // some paths so to be able to eliminate it on others ala PRE.  This
  1144 // would probably require some more extensive graph manipulation to
  1145 // guarantee that the memory edges were all handled correctly.
  1146 //
  1147 // Assuming p is a simple predicate which can't trap in any way and s
  1148 // is a synchronized method consider this code:
  1149 //
  1150 //   s();
  1151 //   if (p)
  1152 //     s();
  1153 //   else
  1154 //     s();
  1155 //   s();
  1156 //
  1157 // 1. The unlocks of the first call to s can be eliminated if the
  1158 // locks inside the then and else branches are eliminated.
  1159 //
  1160 // 2. The unlocks of the then and else branches can be eliminated if
  1161 // the lock of the final call to s is eliminated.
  1162 //
  1163 // Either of these cases subsumes the simple case of sequential control flow
  1164 //
  1165 // Addtionally we can eliminate versions without the else case:
  1166 //
  1167 //   s();
  1168 //   if (p)
  1169 //     s();
  1170 //   s();
  1171 //
  1172 // 3. In this case we eliminate the unlock of the first s, the lock
  1173 // and unlock in the then case and the lock in the final s.
  1174 //
  1175 // Note also that in all these cases the then/else pieces don't have
  1176 // to be trivial as long as they begin and end with synchronization
  1177 // operations.
  1178 //
  1179 //   s();
  1180 //   if (p)
  1181 //     s();
  1182 //     f();
  1183 //     s();
  1184 //   s();
  1185 //
  1186 // The code will work properly for this case, leaving in the unlock
  1187 // before the call to f and the relock after it.
  1188 //
  1189 // A potentially interesting case which isn't handled here is when the
  1190 // locking is partially redundant.
  1191 //
  1192 //   s();
  1193 //   if (p)
  1194 //     s();
  1195 //
  1196 // This could be eliminated putting unlocking on the else case and
  1197 // eliminating the first unlock and the lock in the then side.
  1198 // Alternatively the unlock could be moved out of the then side so it
  1199 // was after the merge and the first unlock and second lock
  1200 // eliminated.  This might require less manipulation of the memory
  1201 // state to get correct.
  1202 //
  1203 // Additionally we might allow work between a unlock and lock before
  1204 // giving up eliminating the locks.  The current code disallows any
  1205 // conditional control flow between these operations.  A formulation
  1206 // similar to partial redundancy elimination computing the
  1207 // availability of unlocking and the anticipatability of locking at a
  1208 // program point would allow detection of fully redundant locking with
  1209 // some amount of work in between.  I'm not sure how often I really
  1210 // think that would occur though.  Most of the cases I've seen
  1211 // indicate it's likely non-trivial work would occur in between.
  1212 // There may be other more complicated constructs where we could
  1213 // eliminate locking but I haven't seen any others appear as hot or
  1214 // interesting.
  1215 //
  1216 // Locking and unlocking have a canonical form in ideal that looks
  1217 // roughly like this:
  1218 //
  1219 //              <obj>
  1220 //                | \\------+
  1221 //                |  \       \
  1222 //                | BoxLock   \
  1223 //                |  |   |     \
  1224 //                |  |    \     \
  1225 //                |  |   FastLock
  1226 //                |  |   /
  1227 //                |  |  /
  1228 //                |  |  |
  1229 //
  1230 //               Lock
  1231 //                |
  1232 //            Proj #0
  1233 //                |
  1234 //            MembarAcquire
  1235 //                |
  1236 //            Proj #0
  1237 //
  1238 //            MembarRelease
  1239 //                |
  1240 //            Proj #0
  1241 //                |
  1242 //              Unlock
  1243 //                |
  1244 //            Proj #0
  1245 //
  1246 //
  1247 // This code proceeds by processing Lock nodes during PhaseIterGVN
  1248 // and searching back through its control for the proper code
  1249 // patterns.  Once it finds a set of lock and unlock operations to
  1250 // eliminate they are marked as eliminatable which causes the
  1251 // expansion of the Lock and Unlock macro nodes to make the operation a NOP
  1252 //
  1253 //=============================================================================
  1255 //
  1256 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:
  1257 //   - copy regions.  (These may not have been optimized away yet.)
  1258 //   - eliminated locking nodes
  1259 //
  1260 static Node *next_control(Node *ctrl) {
  1261   if (ctrl == NULL)
  1262     return NULL;
  1263   while (1) {
  1264     if (ctrl->is_Region()) {
  1265       RegionNode *r = ctrl->as_Region();
  1266       Node *n = r->is_copy();
  1267       if (n == NULL)
  1268         break;  // hit a region, return it
  1269       else
  1270         ctrl = n;
  1271     } else if (ctrl->is_Proj()) {
  1272       Node *in0 = ctrl->in(0);
  1273       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {
  1274         ctrl = in0->in(0);
  1275       } else {
  1276         break;
  1278     } else {
  1279       break; // found an interesting control
  1282   return ctrl;
  1284 //
  1285 // Given a control, see if it's the control projection of an Unlock which
  1286 // operating on the same object as lock.
  1287 //
  1288 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,
  1289                                             GrowableArray<AbstractLockNode*> &lock_ops) {
  1290   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : NULL;
  1291   if (ctrl_proj != NULL && ctrl_proj->_con == TypeFunc::Control) {
  1292     Node *n = ctrl_proj->in(0);
  1293     if (n != NULL && n->is_Unlock()) {
  1294       UnlockNode *unlock = n->as_Unlock();
  1295       if ((lock->obj_node() == unlock->obj_node()) &&
  1296           (lock->box_node() == unlock->box_node()) && !unlock->is_eliminated()) {
  1297         lock_ops.append(unlock);
  1298         return true;
  1302   return false;
  1305 //
  1306 // Find the lock matching an unlock.  Returns null if a safepoint
  1307 // or complicated control is encountered first.
  1308 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {
  1309   LockNode *lock_result = NULL;
  1310   // find the matching lock, or an intervening safepoint
  1311   Node *ctrl = next_control(unlock->in(0));
  1312   while (1) {
  1313     assert(ctrl != NULL, "invalid control graph");
  1314     assert(!ctrl->is_Start(), "missing lock for unlock");
  1315     if (ctrl->is_top()) break;  // dead control path
  1316     if (ctrl->is_Proj()) ctrl = ctrl->in(0);
  1317     if (ctrl->is_SafePoint()) {
  1318         break;  // found a safepoint (may be the lock we are searching for)
  1319     } else if (ctrl->is_Region()) {
  1320       // Check for a simple diamond pattern.  Punt on anything more complicated
  1321       if (ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(2) != NULL) {
  1322         Node *in1 = next_control(ctrl->in(1));
  1323         Node *in2 = next_control(ctrl->in(2));
  1324         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||
  1325              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {
  1326           ctrl = next_control(in1->in(0)->in(0));
  1327         } else {
  1328           break;
  1330       } else {
  1331         break;
  1333     } else {
  1334       ctrl = next_control(ctrl->in(0));  // keep searching
  1337   if (ctrl->is_Lock()) {
  1338     LockNode *lock = ctrl->as_Lock();
  1339     if ((lock->obj_node() == unlock->obj_node()) &&
  1340             (lock->box_node() == unlock->box_node())) {
  1341       lock_result = lock;
  1344   return lock_result;
  1347 // This code corresponds to case 3 above.
  1349 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,
  1350                                                        GrowableArray<AbstractLockNode*> &lock_ops) {
  1351   Node* if_node = node->in(0);
  1352   bool  if_true = node->is_IfTrue();
  1354   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {
  1355     Node *lock_ctrl = next_control(if_node->in(0));
  1356     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {
  1357       Node* lock1_node = NULL;
  1358       ProjNode* proj = if_node->as_If()->proj_out(!if_true);
  1359       if (if_true) {
  1360         if (proj->is_IfFalse() && proj->outcnt() == 1) {
  1361           lock1_node = proj->unique_out();
  1363       } else {
  1364         if (proj->is_IfTrue() && proj->outcnt() == 1) {
  1365           lock1_node = proj->unique_out();
  1368       if (lock1_node != NULL && lock1_node->is_Lock()) {
  1369         LockNode *lock1 = lock1_node->as_Lock();
  1370         if ((lock->obj_node() == lock1->obj_node()) &&
  1371             (lock->box_node() == lock1->box_node()) && !lock1->is_eliminated()) {
  1372           lock_ops.append(lock1);
  1373           return true;
  1379   lock_ops.trunc_to(0);
  1380   return false;
  1383 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,
  1384                                GrowableArray<AbstractLockNode*> &lock_ops) {
  1385   // check each control merging at this point for a matching unlock.
  1386   // in(0) should be self edge so skip it.
  1387   for (int i = 1; i < (int)region->req(); i++) {
  1388     Node *in_node = next_control(region->in(i));
  1389     if (in_node != NULL) {
  1390       if (find_matching_unlock(in_node, lock, lock_ops)) {
  1391         // found a match so keep on checking.
  1392         continue;
  1393       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {
  1394         continue;
  1397       // If we fall through to here then it was some kind of node we
  1398       // don't understand or there wasn't a matching unlock, so give
  1399       // up trying to merge locks.
  1400       lock_ops.trunc_to(0);
  1401       return false;
  1404   return true;
  1408 #ifndef PRODUCT
  1409 //
  1410 // Create a counter which counts the number of times this lock is acquired
  1411 //
  1412 void AbstractLockNode::create_lock_counter(JVMState* state) {
  1413   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);
  1415 #endif
  1417 void AbstractLockNode::set_eliminated() {
  1418   _eliminate = true;
  1419 #ifndef PRODUCT
  1420   if (_counter) {
  1421     // Update the counter to indicate that this lock was eliminated.
  1422     // The counter update code will stay around even though the
  1423     // optimizer will eliminate the lock operation itself.
  1424     _counter->set_tag(NamedCounter::EliminatedLockCounter);
  1426 #endif
  1429 //=============================================================================
  1430 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  1432   // perform any generic optimizations first (returns 'this' or NULL)
  1433   Node *result = SafePointNode::Ideal(phase, can_reshape);
  1435   // Now see if we can optimize away this lock.  We don't actually
  1436   // remove the locking here, we simply set the _eliminate flag which
  1437   // prevents macro expansion from expanding the lock.  Since we don't
  1438   // modify the graph, the value returned from this function is the
  1439   // one computed above.
  1440   if (result == NULL && can_reshape && EliminateLocks && !is_eliminated()) {
  1441     //
  1442     // If we are locking an unescaped object, the lock/unlock is unnecessary
  1443     //
  1444     ConnectionGraph *cgr = phase->C->congraph();
  1445     PointsToNode::EscapeState es = PointsToNode::GlobalEscape;
  1446     if (cgr != NULL)
  1447       es = cgr->escape_state(obj_node(), phase);
  1448     if (es != PointsToNode::UnknownEscape && es != PointsToNode::GlobalEscape) {
  1449       // Mark it eliminated to update any counters
  1450       this->set_eliminated();
  1451       return result;
  1454     //
  1455     // Try lock coarsening
  1456     //
  1457     PhaseIterGVN* iter = phase->is_IterGVN();
  1458     if (iter != NULL) {
  1460       GrowableArray<AbstractLockNode*>   lock_ops;
  1462       Node *ctrl = next_control(in(0));
  1464       // now search back for a matching Unlock
  1465       if (find_matching_unlock(ctrl, this, lock_ops)) {
  1466         // found an unlock directly preceding this lock.  This is the
  1467         // case of single unlock directly control dependent on a
  1468         // single lock which is the trivial version of case 1 or 2.
  1469       } else if (ctrl->is_Region() ) {
  1470         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {
  1471         // found lock preceded by multiple unlocks along all paths
  1472         // joining at this point which is case 3 in description above.
  1474       } else {
  1475         // see if this lock comes from either half of an if and the
  1476         // predecessors merges unlocks and the other half of the if
  1477         // performs a lock.
  1478         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {
  1479           // found unlock splitting to an if with locks on both branches.
  1483       if (lock_ops.length() > 0) {
  1484         // add ourselves to the list of locks to be eliminated.
  1485         lock_ops.append(this);
  1487   #ifndef PRODUCT
  1488         if (PrintEliminateLocks) {
  1489           int locks = 0;
  1490           int unlocks = 0;
  1491           for (int i = 0; i < lock_ops.length(); i++) {
  1492             AbstractLockNode* lock = lock_ops.at(i);
  1493             if (lock->Opcode() == Op_Lock)
  1494               locks++;
  1495             else
  1496               unlocks++;
  1497             if (Verbose) {
  1498               lock->dump(1);
  1501           tty->print_cr("***Eliminated %d unlocks and %d locks", unlocks, locks);
  1503   #endif
  1505         // for each of the identified locks, mark them
  1506         // as eliminatable
  1507         for (int i = 0; i < lock_ops.length(); i++) {
  1508           AbstractLockNode* lock = lock_ops.at(i);
  1510           // Mark it eliminated to update any counters
  1511           lock->set_eliminated();
  1512           lock->set_coarsened();
  1514       } else if (result != NULL && ctrl->is_Region() &&
  1515                  iter->_worklist.member(ctrl)) {
  1516         // We weren't able to find any opportunities but the region this
  1517         // lock is control dependent on hasn't been processed yet so put
  1518         // this lock back on the worklist so we can check again once any
  1519         // region simplification has occurred.
  1520         iter->_worklist.push(this);
  1525   return result;
  1528 //=============================================================================
  1529 uint UnlockNode::size_of() const { return sizeof(*this); }
  1531 //=============================================================================
  1532 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  1534   // perform any generic optimizations first (returns 'this' or NULL)
  1535   Node * result = SafePointNode::Ideal(phase, can_reshape);
  1537   // Now see if we can optimize away this unlock.  We don't actually
  1538   // remove the unlocking here, we simply set the _eliminate flag which
  1539   // prevents macro expansion from expanding the unlock.  Since we don't
  1540   // modify the graph, the value returned from this function is the
  1541   // one computed above.
  1542   // Escape state is defined after Parse phase.
  1543   if (result == NULL && can_reshape && EliminateLocks && !is_eliminated()) {
  1544     //
  1545     // If we are unlocking an unescaped object, the lock/unlock is unnecessary.
  1546     //
  1547     ConnectionGraph *cgr = phase->C->congraph();
  1548     PointsToNode::EscapeState es = PointsToNode::GlobalEscape;
  1549     if (cgr != NULL)
  1550       es = cgr->escape_state(obj_node(), phase);
  1551     if (es != PointsToNode::UnknownEscape && es != PointsToNode::GlobalEscape) {
  1552       // Mark it eliminated to update any counters
  1553       this->set_eliminated();
  1556   return result;

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