src/share/vm/opto/lcm.cpp

Mon, 31 Oct 2011 03:06:42 -0700

author
twisti
date
Mon, 31 Oct 2011 03:06:42 -0700
changeset 3249
e3b0dcc327b9
parent 3040
c7b60b601eb4
child 3316
f03a3c8bd5e5
permissions
-rw-r--r--

7104561: UseRDPCForConstantTableBase doesn't work after shorten branches changes
Reviewed-by: never, kvn

     1 /*
     2  * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #include "precompiled.hpp"
    26 #include "memory/allocation.inline.hpp"
    27 #include "opto/block.hpp"
    28 #include "opto/c2compiler.hpp"
    29 #include "opto/callnode.hpp"
    30 #include "opto/cfgnode.hpp"
    31 #include "opto/machnode.hpp"
    32 #include "opto/runtime.hpp"
    33 #ifdef TARGET_ARCH_MODEL_x86_32
    34 # include "adfiles/ad_x86_32.hpp"
    35 #endif
    36 #ifdef TARGET_ARCH_MODEL_x86_64
    37 # include "adfiles/ad_x86_64.hpp"
    38 #endif
    39 #ifdef TARGET_ARCH_MODEL_sparc
    40 # include "adfiles/ad_sparc.hpp"
    41 #endif
    42 #ifdef TARGET_ARCH_MODEL_zero
    43 # include "adfiles/ad_zero.hpp"
    44 #endif
    45 #ifdef TARGET_ARCH_MODEL_arm
    46 # include "adfiles/ad_arm.hpp"
    47 #endif
    48 #ifdef TARGET_ARCH_MODEL_ppc
    49 # include "adfiles/ad_ppc.hpp"
    50 #endif
    52 // Optimization - Graph Style
    54 //------------------------------implicit_null_check----------------------------
    55 // Detect implicit-null-check opportunities.  Basically, find NULL checks
    56 // with suitable memory ops nearby.  Use the memory op to do the NULL check.
    57 // I can generate a memory op if there is not one nearby.
    58 // The proj is the control projection for the not-null case.
    59 // The val is the pointer being checked for nullness or
    60 // decodeHeapOop_not_null node if it did not fold into address.
    61 void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowed_reasons) {
    62   // Assume if null check need for 0 offset then always needed
    63   // Intel solaris doesn't support any null checks yet and no
    64   // mechanism exists (yet) to set the switches at an os_cpu level
    65   if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
    67   // Make sure the ptr-is-null path appears to be uncommon!
    68   float f = end()->as_MachIf()->_prob;
    69   if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
    70   if( f > PROB_UNLIKELY_MAG(4) ) return;
    72   uint bidx = 0;                // Capture index of value into memop
    73   bool was_store;               // Memory op is a store op
    75   // Get the successor block for if the test ptr is non-null
    76   Block* not_null_block;  // this one goes with the proj
    77   Block* null_block;
    78   if (_nodes[_nodes.size()-1] == proj) {
    79     null_block     = _succs[0];
    80     not_null_block = _succs[1];
    81   } else {
    82     assert(_nodes[_nodes.size()-2] == proj, "proj is one or the other");
    83     not_null_block = _succs[0];
    84     null_block     = _succs[1];
    85   }
    86   while (null_block->is_Empty() == Block::empty_with_goto) {
    87     null_block     = null_block->_succs[0];
    88   }
    90   // Search the exception block for an uncommon trap.
    91   // (See Parse::do_if and Parse::do_ifnull for the reason
    92   // we need an uncommon trap.  Briefly, we need a way to
    93   // detect failure of this optimization, as in 6366351.)
    94   {
    95     bool found_trap = false;
    96     for (uint i1 = 0; i1 < null_block->_nodes.size(); i1++) {
    97       Node* nn = null_block->_nodes[i1];
    98       if (nn->is_MachCall() &&
    99           nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
   100         const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
   101         if (trtype->isa_int() && trtype->is_int()->is_con()) {
   102           jint tr_con = trtype->is_int()->get_con();
   103           Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
   104           Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
   105           assert((int)reason < (int)BitsPerInt, "recode bit map");
   106           if (is_set_nth_bit(allowed_reasons, (int) reason)
   107               && action != Deoptimization::Action_none) {
   108             // This uncommon trap is sure to recompile, eventually.
   109             // When that happens, C->too_many_traps will prevent
   110             // this transformation from happening again.
   111             found_trap = true;
   112           }
   113         }
   114         break;
   115       }
   116     }
   117     if (!found_trap) {
   118       // We did not find an uncommon trap.
   119       return;
   120     }
   121   }
   123   // Check for decodeHeapOop_not_null node which did not fold into address
   124   bool is_decoden = ((intptr_t)val) & 1;
   125   val = (Node*)(((intptr_t)val) & ~1);
   127   assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
   128          (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
   130   // Search the successor block for a load or store who's base value is also
   131   // the tested value.  There may be several.
   132   Node_List *out = new Node_List(Thread::current()->resource_area());
   133   MachNode *best = NULL;        // Best found so far
   134   for (DUIterator i = val->outs(); val->has_out(i); i++) {
   135     Node *m = val->out(i);
   136     if( !m->is_Mach() ) continue;
   137     MachNode *mach = m->as_Mach();
   138     was_store = false;
   139     int iop = mach->ideal_Opcode();
   140     switch( iop ) {
   141     case Op_LoadB:
   142     case Op_LoadUS:
   143     case Op_LoadD:
   144     case Op_LoadF:
   145     case Op_LoadI:
   146     case Op_LoadL:
   147     case Op_LoadP:
   148     case Op_LoadN:
   149     case Op_LoadS:
   150     case Op_LoadKlass:
   151     case Op_LoadNKlass:
   152     case Op_LoadRange:
   153     case Op_LoadD_unaligned:
   154     case Op_LoadL_unaligned:
   155       assert(mach->in(2) == val, "should be address");
   156       break;
   157     case Op_StoreB:
   158     case Op_StoreC:
   159     case Op_StoreCM:
   160     case Op_StoreD:
   161     case Op_StoreF:
   162     case Op_StoreI:
   163     case Op_StoreL:
   164     case Op_StoreP:
   165     case Op_StoreN:
   166       was_store = true;         // Memory op is a store op
   167       // Stores will have their address in slot 2 (memory in slot 1).
   168       // If the value being nul-checked is in another slot, it means we
   169       // are storing the checked value, which does NOT check the value!
   170       if( mach->in(2) != val ) continue;
   171       break;                    // Found a memory op?
   172     case Op_StrComp:
   173     case Op_StrEquals:
   174     case Op_StrIndexOf:
   175     case Op_AryEq:
   176       // Not a legit memory op for implicit null check regardless of
   177       // embedded loads
   178       continue;
   179     default:                    // Also check for embedded loads
   180       if( !mach->needs_anti_dependence_check() )
   181         continue;               // Not an memory op; skip it
   182       if( must_clone[iop] ) {
   183         // Do not move nodes which produce flags because
   184         // RA will try to clone it to place near branch and
   185         // it will cause recompilation, see clone_node().
   186         continue;
   187       }
   188       {
   189         // Check that value is used in memory address in
   190         // instructions with embedded load (CmpP val1,(val2+off)).
   191         Node* base;
   192         Node* index;
   193         const MachOper* oper = mach->memory_inputs(base, index);
   194         if (oper == NULL || oper == (MachOper*)-1) {
   195           continue;             // Not an memory op; skip it
   196         }
   197         if (val == base ||
   198             val == index && val->bottom_type()->isa_narrowoop()) {
   199           break;                // Found it
   200         } else {
   201           continue;             // Skip it
   202         }
   203       }
   204       break;
   205     }
   206     // check if the offset is not too high for implicit exception
   207     {
   208       intptr_t offset = 0;
   209       const TypePtr *adr_type = NULL;  // Do not need this return value here
   210       const Node* base = mach->get_base_and_disp(offset, adr_type);
   211       if (base == NULL || base == NodeSentinel) {
   212         // Narrow oop address doesn't have base, only index
   213         if( val->bottom_type()->isa_narrowoop() &&
   214             MacroAssembler::needs_explicit_null_check(offset) )
   215           continue;             // Give up if offset is beyond page size
   216         // cannot reason about it; is probably not implicit null exception
   217       } else {
   218         const TypePtr* tptr;
   219         if (UseCompressedOops && Universe::narrow_oop_shift() == 0) {
   220           // 32-bits narrow oop can be the base of address expressions
   221           tptr = base->bottom_type()->make_ptr();
   222         } else {
   223           // only regular oops are expected here
   224           tptr = base->bottom_type()->is_ptr();
   225         }
   226         // Give up if offset is not a compile-time constant
   227         if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
   228           continue;
   229         offset += tptr->_offset; // correct if base is offseted
   230         if( MacroAssembler::needs_explicit_null_check(offset) )
   231           continue;             // Give up is reference is beyond 4K page size
   232       }
   233     }
   235     // Check ctrl input to see if the null-check dominates the memory op
   236     Block *cb = cfg->_bbs[mach->_idx];
   237     cb = cb->_idom;             // Always hoist at least 1 block
   238     if( !was_store ) {          // Stores can be hoisted only one block
   239       while( cb->_dom_depth > (_dom_depth + 1))
   240         cb = cb->_idom;         // Hoist loads as far as we want
   241       // The non-null-block should dominate the memory op, too. Live
   242       // range spilling will insert a spill in the non-null-block if it is
   243       // needs to spill the memory op for an implicit null check.
   244       if (cb->_dom_depth == (_dom_depth + 1)) {
   245         if (cb != not_null_block) continue;
   246         cb = cb->_idom;
   247       }
   248     }
   249     if( cb != this ) continue;
   251     // Found a memory user; see if it can be hoisted to check-block
   252     uint vidx = 0;              // Capture index of value into memop
   253     uint j;
   254     for( j = mach->req()-1; j > 0; j-- ) {
   255       if( mach->in(j) == val ) {
   256         vidx = j;
   257         // Ignore DecodeN val which could be hoisted to where needed.
   258         if( is_decoden ) continue;
   259       }
   260       // Block of memory-op input
   261       Block *inb = cfg->_bbs[mach->in(j)->_idx];
   262       Block *b = this;          // Start from nul check
   263       while( b != inb && b->_dom_depth > inb->_dom_depth )
   264         b = b->_idom;           // search upwards for input
   265       // See if input dominates null check
   266       if( b != inb )
   267         break;
   268     }
   269     if( j > 0 )
   270       continue;
   271     Block *mb = cfg->_bbs[mach->_idx];
   272     // Hoisting stores requires more checks for the anti-dependence case.
   273     // Give up hoisting if we have to move the store past any load.
   274     if( was_store ) {
   275       Block *b = mb;            // Start searching here for a local load
   276       // mach use (faulting) trying to hoist
   277       // n might be blocker to hoisting
   278       while( b != this ) {
   279         uint k;
   280         for( k = 1; k < b->_nodes.size(); k++ ) {
   281           Node *n = b->_nodes[k];
   282           if( n->needs_anti_dependence_check() &&
   283               n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
   284             break;              // Found anti-dependent load
   285         }
   286         if( k < b->_nodes.size() )
   287           break;                // Found anti-dependent load
   288         // Make sure control does not do a merge (would have to check allpaths)
   289         if( b->num_preds() != 2 ) break;
   290         b = cfg->_bbs[b->pred(1)->_idx]; // Move up to predecessor block
   291       }
   292       if( b != this ) continue;
   293     }
   295     // Make sure this memory op is not already being used for a NullCheck
   296     Node *e = mb->end();
   297     if( e->is_MachNullCheck() && e->in(1) == mach )
   298       continue;                 // Already being used as a NULL check
   300     // Found a candidate!  Pick one with least dom depth - the highest
   301     // in the dom tree should be closest to the null check.
   302     if( !best ||
   303         cfg->_bbs[mach->_idx]->_dom_depth < cfg->_bbs[best->_idx]->_dom_depth ) {
   304       best = mach;
   305       bidx = vidx;
   307     }
   308   }
   309   // No candidate!
   310   if( !best ) return;
   312   // ---- Found an implicit null check
   313   extern int implicit_null_checks;
   314   implicit_null_checks++;
   316   if( is_decoden ) {
   317     // Check if we need to hoist decodeHeapOop_not_null first.
   318     Block *valb = cfg->_bbs[val->_idx];
   319     if( this != valb && this->_dom_depth < valb->_dom_depth ) {
   320       // Hoist it up to the end of the test block.
   321       valb->find_remove(val);
   322       this->add_inst(val);
   323       cfg->_bbs.map(val->_idx,this);
   324       // DecodeN on x86 may kill flags. Check for flag-killing projections
   325       // that also need to be hoisted.
   326       for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
   327         Node* n = val->fast_out(j);
   328         if( n->is_MachProj() ) {
   329           cfg->_bbs[n->_idx]->find_remove(n);
   330           this->add_inst(n);
   331           cfg->_bbs.map(n->_idx,this);
   332         }
   333       }
   334     }
   335   }
   336   // Hoist the memory candidate up to the end of the test block.
   337   Block *old_block = cfg->_bbs[best->_idx];
   338   old_block->find_remove(best);
   339   add_inst(best);
   340   cfg->_bbs.map(best->_idx,this);
   342   // Move the control dependence
   343   if (best->in(0) && best->in(0) == old_block->_nodes[0])
   344     best->set_req(0, _nodes[0]);
   346   // Check for flag-killing projections that also need to be hoisted
   347   // Should be DU safe because no edge updates.
   348   for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
   349     Node* n = best->fast_out(j);
   350     if( n->is_MachProj() ) {
   351       cfg->_bbs[n->_idx]->find_remove(n);
   352       add_inst(n);
   353       cfg->_bbs.map(n->_idx,this);
   354     }
   355   }
   357   Compile *C = cfg->C;
   358   // proj==Op_True --> ne test; proj==Op_False --> eq test.
   359   // One of two graph shapes got matched:
   360   //   (IfTrue  (If (Bool NE (CmpP ptr NULL))))
   361   //   (IfFalse (If (Bool EQ (CmpP ptr NULL))))
   362   // NULL checks are always branch-if-eq.  If we see a IfTrue projection
   363   // then we are replacing a 'ne' test with a 'eq' NULL check test.
   364   // We need to flip the projections to keep the same semantics.
   365   if( proj->Opcode() == Op_IfTrue ) {
   366     // Swap order of projections in basic block to swap branch targets
   367     Node *tmp1 = _nodes[end_idx()+1];
   368     Node *tmp2 = _nodes[end_idx()+2];
   369     _nodes.map(end_idx()+1, tmp2);
   370     _nodes.map(end_idx()+2, tmp1);
   371     Node *tmp = new (C, 1) Node(C->top()); // Use not NULL input
   372     tmp1->replace_by(tmp);
   373     tmp2->replace_by(tmp1);
   374     tmp->replace_by(tmp2);
   375     tmp->destruct();
   376   }
   378   // Remove the existing null check; use a new implicit null check instead.
   379   // Since schedule-local needs precise def-use info, we need to correct
   380   // it as well.
   381   Node *old_tst = proj->in(0);
   382   MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
   383   _nodes.map(end_idx(),nul_chk);
   384   cfg->_bbs.map(nul_chk->_idx,this);
   385   // Redirect users of old_test to nul_chk
   386   for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
   387     old_tst->last_out(i2)->set_req(0, nul_chk);
   388   // Clean-up any dead code
   389   for (uint i3 = 0; i3 < old_tst->req(); i3++)
   390     old_tst->set_req(i3, NULL);
   392   cfg->latency_from_uses(nul_chk);
   393   cfg->latency_from_uses(best);
   394 }
   397 //------------------------------select-----------------------------------------
   398 // Select a nice fellow from the worklist to schedule next. If there is only
   399 // one choice, then use it. Projections take top priority for correctness
   400 // reasons - if I see a projection, then it is next.  There are a number of
   401 // other special cases, for instructions that consume condition codes, et al.
   402 // These are chosen immediately. Some instructions are required to immediately
   403 // precede the last instruction in the block, and these are taken last. Of the
   404 // remaining cases (most), choose the instruction with the greatest latency
   405 // (that is, the most number of pseudo-cycles required to the end of the
   406 // routine). If there is a tie, choose the instruction with the most inputs.
   407 Node *Block::select(PhaseCFG *cfg, Node_List &worklist, int *ready_cnt, VectorSet &next_call, uint sched_slot) {
   409   // If only a single entry on the stack, use it
   410   uint cnt = worklist.size();
   411   if (cnt == 1) {
   412     Node *n = worklist[0];
   413     worklist.map(0,worklist.pop());
   414     return n;
   415   }
   417   uint choice  = 0; // Bigger is most important
   418   uint latency = 0; // Bigger is scheduled first
   419   uint score   = 0; // Bigger is better
   420   int idx = -1;     // Index in worklist
   422   for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
   423     // Order in worklist is used to break ties.
   424     // See caller for how this is used to delay scheduling
   425     // of induction variable increments to after the other
   426     // uses of the phi are scheduled.
   427     Node *n = worklist[i];      // Get Node on worklist
   429     int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
   430     if( n->is_Proj() ||         // Projections always win
   431         n->Opcode()== Op_Con || // So does constant 'Top'
   432         iop == Op_CreateEx ||   // Create-exception must start block
   433         iop == Op_CheckCastPP
   434         ) {
   435       worklist.map(i,worklist.pop());
   436       return n;
   437     }
   439     // Final call in a block must be adjacent to 'catch'
   440     Node *e = end();
   441     if( e->is_Catch() && e->in(0)->in(0) == n )
   442       continue;
   444     // Memory op for an implicit null check has to be at the end of the block
   445     if( e->is_MachNullCheck() && e->in(1) == n )
   446       continue;
   448     uint n_choice  = 2;
   450     // See if this instruction is consumed by a branch. If so, then (as the
   451     // branch is the last instruction in the basic block) force it to the
   452     // end of the basic block
   453     if ( must_clone[iop] ) {
   454       // See if any use is a branch
   455       bool found_machif = false;
   457       for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
   458         Node* use = n->fast_out(j);
   460         // The use is a conditional branch, make them adjacent
   461         if (use->is_MachIf() && cfg->_bbs[use->_idx]==this ) {
   462           found_machif = true;
   463           break;
   464         }
   466         // More than this instruction pending for successor to be ready,
   467         // don't choose this if other opportunities are ready
   468         if (ready_cnt[use->_idx] > 1)
   469           n_choice = 1;
   470       }
   472       // loop terminated, prefer not to use this instruction
   473       if (found_machif)
   474         continue;
   475     }
   477     // See if this has a predecessor that is "must_clone", i.e. sets the
   478     // condition code. If so, choose this first
   479     for (uint j = 0; j < n->req() ; j++) {
   480       Node *inn = n->in(j);
   481       if (inn) {
   482         if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
   483           n_choice = 3;
   484           break;
   485         }
   486       }
   487     }
   489     // MachTemps should be scheduled last so they are near their uses
   490     if (n->is_MachTemp()) {
   491       n_choice = 1;
   492     }
   494     uint n_latency = cfg->_node_latency->at_grow(n->_idx);
   495     uint n_score   = n->req();   // Many inputs get high score to break ties
   497     // Keep best latency found
   498     if( choice < n_choice ||
   499         ( choice == n_choice &&
   500           ( latency < n_latency ||
   501             ( latency == n_latency &&
   502               ( score < n_score ))))) {
   503       choice  = n_choice;
   504       latency = n_latency;
   505       score   = n_score;
   506       idx     = i;               // Also keep index in worklist
   507     }
   508   } // End of for all ready nodes in worklist
   510   assert(idx >= 0, "index should be set");
   511   Node *n = worklist[(uint)idx];      // Get the winner
   513   worklist.map((uint)idx, worklist.pop());     // Compress worklist
   514   return n;
   515 }
   518 //------------------------------set_next_call----------------------------------
   519 void Block::set_next_call( Node *n, VectorSet &next_call, Block_Array &bbs ) {
   520   if( next_call.test_set(n->_idx) ) return;
   521   for( uint i=0; i<n->len(); i++ ) {
   522     Node *m = n->in(i);
   523     if( !m ) continue;  // must see all nodes in block that precede call
   524     if( bbs[m->_idx] == this )
   525       set_next_call( m, next_call, bbs );
   526   }
   527 }
   529 //------------------------------needed_for_next_call---------------------------
   530 // Set the flag 'next_call' for each Node that is needed for the next call to
   531 // be scheduled.  This flag lets me bias scheduling so Nodes needed for the
   532 // next subroutine call get priority - basically it moves things NOT needed
   533 // for the next call till after the call.  This prevents me from trying to
   534 // carry lots of stuff live across a call.
   535 void Block::needed_for_next_call(Node *this_call, VectorSet &next_call, Block_Array &bbs) {
   536   // Find the next control-defining Node in this block
   537   Node* call = NULL;
   538   for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
   539     Node* m = this_call->fast_out(i);
   540     if( bbs[m->_idx] == this && // Local-block user
   541         m != this_call &&       // Not self-start node
   542         m->is_MachCall() )
   543       call = m;
   544       break;
   545   }
   546   if (call == NULL)  return;    // No next call (e.g., block end is near)
   547   // Set next-call for all inputs to this call
   548   set_next_call(call, next_call, bbs);
   549 }
   551 //------------------------------sched_call-------------------------------------
   552 uint Block::sched_call( Matcher &matcher, Block_Array &bbs, uint node_cnt, Node_List &worklist, int *ready_cnt, MachCallNode *mcall, VectorSet &next_call ) {
   553   RegMask regs;
   555   // Schedule all the users of the call right now.  All the users are
   556   // projection Nodes, so they must be scheduled next to the call.
   557   // Collect all the defined registers.
   558   for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
   559     Node* n = mcall->fast_out(i);
   560     assert( n->is_MachProj(), "" );
   561     --ready_cnt[n->_idx];
   562     assert( !ready_cnt[n->_idx], "" );
   563     // Schedule next to call
   564     _nodes.map(node_cnt++, n);
   565     // Collect defined registers
   566     regs.OR(n->out_RegMask());
   567     // Check for scheduling the next control-definer
   568     if( n->bottom_type() == Type::CONTROL )
   569       // Warm up next pile of heuristic bits
   570       needed_for_next_call(n, next_call, bbs);
   572     // Children of projections are now all ready
   573     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
   574       Node* m = n->fast_out(j); // Get user
   575       if( bbs[m->_idx] != this ) continue;
   576       if( m->is_Phi() ) continue;
   577       if( !--ready_cnt[m->_idx] )
   578         worklist.push(m);
   579     }
   581   }
   583   // Act as if the call defines the Frame Pointer.
   584   // Certainly the FP is alive and well after the call.
   585   regs.Insert(matcher.c_frame_pointer());
   587   // Set all registers killed and not already defined by the call.
   588   uint r_cnt = mcall->tf()->range()->cnt();
   589   int op = mcall->ideal_Opcode();
   590   MachProjNode *proj = new (matcher.C, 1) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
   591   bbs.map(proj->_idx,this);
   592   _nodes.insert(node_cnt++, proj);
   594   // Select the right register save policy.
   595   const char * save_policy;
   596   switch (op) {
   597     case Op_CallRuntime:
   598     case Op_CallLeaf:
   599     case Op_CallLeafNoFP:
   600       // Calling C code so use C calling convention
   601       save_policy = matcher._c_reg_save_policy;
   602       break;
   604     case Op_CallStaticJava:
   605     case Op_CallDynamicJava:
   606       // Calling Java code so use Java calling convention
   607       save_policy = matcher._register_save_policy;
   608       break;
   610     default:
   611       ShouldNotReachHere();
   612   }
   614   // When using CallRuntime mark SOE registers as killed by the call
   615   // so values that could show up in the RegisterMap aren't live in a
   616   // callee saved register since the register wouldn't know where to
   617   // find them.  CallLeaf and CallLeafNoFP are ok because they can't
   618   // have debug info on them.  Strictly speaking this only needs to be
   619   // done for oops since idealreg2debugmask takes care of debug info
   620   // references but there no way to handle oops differently than other
   621   // pointers as far as the kill mask goes.
   622   bool exclude_soe = op == Op_CallRuntime;
   624   // If the call is a MethodHandle invoke, we need to exclude the
   625   // register which is used to save the SP value over MH invokes from
   626   // the mask.  Otherwise this register could be used for
   627   // deoptimization information.
   628   if (op == Op_CallStaticJava) {
   629     MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
   630     if (mcallstaticjava->_method_handle_invoke)
   631       proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
   632   }
   634   // Fill in the kill mask for the call
   635   for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
   636     if( !regs.Member(r) ) {     // Not already defined by the call
   637       // Save-on-call register?
   638       if ((save_policy[r] == 'C') ||
   639           (save_policy[r] == 'A') ||
   640           ((save_policy[r] == 'E') && exclude_soe)) {
   641         proj->_rout.Insert(r);
   642       }
   643     }
   644   }
   646   return node_cnt;
   647 }
   650 //------------------------------schedule_local---------------------------------
   651 // Topological sort within a block.  Someday become a real scheduler.
   652 bool Block::schedule_local(PhaseCFG *cfg, Matcher &matcher, int *ready_cnt, VectorSet &next_call) {
   653   // Already "sorted" are the block start Node (as the first entry), and
   654   // the block-ending Node and any trailing control projections.  We leave
   655   // these alone.  PhiNodes and ParmNodes are made to follow the block start
   656   // Node.  Everything else gets topo-sorted.
   658 #ifndef PRODUCT
   659     if (cfg->trace_opto_pipelining()) {
   660       tty->print_cr("# --- schedule_local B%d, before: ---", _pre_order);
   661       for (uint i = 0;i < _nodes.size();i++) {
   662         tty->print("# ");
   663         _nodes[i]->fast_dump();
   664       }
   665       tty->print_cr("#");
   666     }
   667 #endif
   669   // RootNode is already sorted
   670   if( _nodes.size() == 1 ) return true;
   672   // Move PhiNodes and ParmNodes from 1 to cnt up to the start
   673   uint node_cnt = end_idx();
   674   uint phi_cnt = 1;
   675   uint i;
   676   for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
   677     Node *n = _nodes[i];
   678     if( n->is_Phi() ||          // Found a PhiNode or ParmNode
   679         (n->is_Proj()  && n->in(0) == head()) ) {
   680       // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
   681       _nodes.map(i,_nodes[phi_cnt]);
   682       _nodes.map(phi_cnt++,n);  // swap Phi/Parm up front
   683     } else {                    // All others
   684       // Count block-local inputs to 'n'
   685       uint cnt = n->len();      // Input count
   686       uint local = 0;
   687       for( uint j=0; j<cnt; j++ ) {
   688         Node *m = n->in(j);
   689         if( m && cfg->_bbs[m->_idx] == this && !m->is_top() )
   690           local++;              // One more block-local input
   691       }
   692       ready_cnt[n->_idx] = local; // Count em up
   694 #ifdef ASSERT
   695       if( UseConcMarkSweepGC || UseG1GC ) {
   696         if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
   697           // Check the precedence edges
   698           for (uint prec = n->req(); prec < n->len(); prec++) {
   699             Node* oop_store = n->in(prec);
   700             if (oop_store != NULL) {
   701               assert(cfg->_bbs[oop_store->_idx]->_dom_depth <= this->_dom_depth, "oop_store must dominate card-mark");
   702             }
   703           }
   704         }
   705       }
   706 #endif
   708       // A few node types require changing a required edge to a precedence edge
   709       // before allocation.
   710       if( n->is_Mach() && n->req() > TypeFunc::Parms &&
   711           (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
   712            n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
   713         // MemBarAcquire could be created without Precedent edge.
   714         // del_req() replaces the specified edge with the last input edge
   715         // and then removes the last edge. If the specified edge > number of
   716         // edges the last edge will be moved outside of the input edges array
   717         // and the edge will be lost. This is why this code should be
   718         // executed only when Precedent (== TypeFunc::Parms) edge is present.
   719         Node *x = n->in(TypeFunc::Parms);
   720         n->del_req(TypeFunc::Parms);
   721         n->add_prec(x);
   722       }
   723     }
   724   }
   725   for(uint i2=i; i2<_nodes.size(); i2++ ) // Trailing guys get zapped count
   726     ready_cnt[_nodes[i2]->_idx] = 0;
   728   // All the prescheduled guys do not hold back internal nodes
   729   uint i3;
   730   for(i3 = 0; i3<phi_cnt; i3++ ) {  // For all pre-scheduled
   731     Node *n = _nodes[i3];       // Get pre-scheduled
   732     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
   733       Node* m = n->fast_out(j);
   734       if( cfg->_bbs[m->_idx] ==this ) // Local-block user
   735         ready_cnt[m->_idx]--;   // Fix ready count
   736     }
   737   }
   739   Node_List delay;
   740   // Make a worklist
   741   Node_List worklist;
   742   for(uint i4=i3; i4<node_cnt; i4++ ) {    // Put ready guys on worklist
   743     Node *m = _nodes[i4];
   744     if( !ready_cnt[m->_idx] ) {   // Zero ready count?
   745       if (m->is_iteratively_computed()) {
   746         // Push induction variable increments last to allow other uses
   747         // of the phi to be scheduled first. The select() method breaks
   748         // ties in scheduling by worklist order.
   749         delay.push(m);
   750       } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
   751         // Force the CreateEx to the top of the list so it's processed
   752         // first and ends up at the start of the block.
   753         worklist.insert(0, m);
   754       } else {
   755         worklist.push(m);         // Then on to worklist!
   756       }
   757     }
   758   }
   759   while (delay.size()) {
   760     Node* d = delay.pop();
   761     worklist.push(d);
   762   }
   764   // Warm up the 'next_call' heuristic bits
   765   needed_for_next_call(_nodes[0], next_call, cfg->_bbs);
   767 #ifndef PRODUCT
   768     if (cfg->trace_opto_pipelining()) {
   769       for (uint j=0; j<_nodes.size(); j++) {
   770         Node     *n = _nodes[j];
   771         int     idx = n->_idx;
   772         tty->print("#   ready cnt:%3d  ", ready_cnt[idx]);
   773         tty->print("latency:%3d  ", cfg->_node_latency->at_grow(idx));
   774         tty->print("%4d: %s\n", idx, n->Name());
   775       }
   776     }
   777 #endif
   779   // Pull from worklist and schedule
   780   while( worklist.size() ) {    // Worklist is not ready
   782 #ifndef PRODUCT
   783     if (cfg->trace_opto_pipelining()) {
   784       tty->print("#   ready list:");
   785       for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
   786         Node *n = worklist[i];      // Get Node on worklist
   787         tty->print(" %d", n->_idx);
   788       }
   789       tty->cr();
   790     }
   791 #endif
   793     // Select and pop a ready guy from worklist
   794     Node* n = select(cfg, worklist, ready_cnt, next_call, phi_cnt);
   795     _nodes.map(phi_cnt++,n);    // Schedule him next
   797 #ifndef PRODUCT
   798     if (cfg->trace_opto_pipelining()) {
   799       tty->print("#    select %d: %s", n->_idx, n->Name());
   800       tty->print(", latency:%d", cfg->_node_latency->at_grow(n->_idx));
   801       n->dump();
   802       if (Verbose) {
   803         tty->print("#   ready list:");
   804         for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
   805           Node *n = worklist[i];      // Get Node on worklist
   806           tty->print(" %d", n->_idx);
   807         }
   808         tty->cr();
   809       }
   810     }
   812 #endif
   813     if( n->is_MachCall() ) {
   814       MachCallNode *mcall = n->as_MachCall();
   815       phi_cnt = sched_call(matcher, cfg->_bbs, phi_cnt, worklist, ready_cnt, mcall, next_call);
   816       continue;
   817     }
   818     // Children are now all ready
   819     for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
   820       Node* m = n->fast_out(i5); // Get user
   821       if( cfg->_bbs[m->_idx] != this ) continue;
   822       if( m->is_Phi() ) continue;
   823       if( !--ready_cnt[m->_idx] )
   824         worklist.push(m);
   825     }
   826   }
   828   if( phi_cnt != end_idx() ) {
   829     // did not schedule all.  Retry, Bailout, or Die
   830     Compile* C = matcher.C;
   831     if (C->subsume_loads() == true && !C->failing()) {
   832       // Retry with subsume_loads == false
   833       // If this is the first failure, the sentinel string will "stick"
   834       // to the Compile object, and the C2Compiler will see it and retry.
   835       C->record_failure(C2Compiler::retry_no_subsuming_loads());
   836     }
   837     // assert( phi_cnt == end_idx(), "did not schedule all" );
   838     return false;
   839   }
   841 #ifndef PRODUCT
   842   if (cfg->trace_opto_pipelining()) {
   843     tty->print_cr("#");
   844     tty->print_cr("# after schedule_local");
   845     for (uint i = 0;i < _nodes.size();i++) {
   846       tty->print("# ");
   847       _nodes[i]->fast_dump();
   848     }
   849     tty->cr();
   850   }
   851 #endif
   854   return true;
   855 }
   857 //--------------------------catch_cleanup_fix_all_inputs-----------------------
   858 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
   859   for (uint l = 0; l < use->len(); l++) {
   860     if (use->in(l) == old_def) {
   861       if (l < use->req()) {
   862         use->set_req(l, new_def);
   863       } else {
   864         use->rm_prec(l);
   865         use->add_prec(new_def);
   866         l--;
   867       }
   868     }
   869   }
   870 }
   872 //------------------------------catch_cleanup_find_cloned_def------------------
   873 static Node *catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
   874   assert( use_blk != def_blk, "Inter-block cleanup only");
   876   // The use is some block below the Catch.  Find and return the clone of the def
   877   // that dominates the use. If there is no clone in a dominating block, then
   878   // create a phi for the def in a dominating block.
   880   // Find which successor block dominates this use.  The successor
   881   // blocks must all be single-entry (from the Catch only; I will have
   882   // split blocks to make this so), hence they all dominate.
   883   while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
   884     use_blk = use_blk->_idom;
   886   // Find the successor
   887   Node *fixup = NULL;
   889   uint j;
   890   for( j = 0; j < def_blk->_num_succs; j++ )
   891     if( use_blk == def_blk->_succs[j] )
   892       break;
   894   if( j == def_blk->_num_succs ) {
   895     // Block at same level in dom-tree is not a successor.  It needs a
   896     // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
   897     Node_Array inputs = new Node_List(Thread::current()->resource_area());
   898     for(uint k = 1; k < use_blk->num_preds(); k++) {
   899       inputs.map(k, catch_cleanup_find_cloned_def(bbs[use_blk->pred(k)->_idx], def, def_blk, bbs, n_clone_idx));
   900     }
   902     // Check to see if the use_blk already has an identical phi inserted.
   903     // If it exists, it will be at the first position since all uses of a
   904     // def are processed together.
   905     Node *phi = use_blk->_nodes[1];
   906     if( phi->is_Phi() ) {
   907       fixup = phi;
   908       for (uint k = 1; k < use_blk->num_preds(); k++) {
   909         if (phi->in(k) != inputs[k]) {
   910           // Not a match
   911           fixup = NULL;
   912           break;
   913         }
   914       }
   915     }
   917     // If an existing PhiNode was not found, make a new one.
   918     if (fixup == NULL) {
   919       Node *new_phi = PhiNode::make(use_blk->head(), def);
   920       use_blk->_nodes.insert(1, new_phi);
   921       bbs.map(new_phi->_idx, use_blk);
   922       for (uint k = 1; k < use_blk->num_preds(); k++) {
   923         new_phi->set_req(k, inputs[k]);
   924       }
   925       fixup = new_phi;
   926     }
   928   } else {
   929     // Found the use just below the Catch.  Make it use the clone.
   930     fixup = use_blk->_nodes[n_clone_idx];
   931   }
   933   return fixup;
   934 }
   936 //--------------------------catch_cleanup_intra_block--------------------------
   937 // Fix all input edges in use that reference "def".  The use is in the same
   938 // block as the def and both have been cloned in each successor block.
   939 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
   941   // Both the use and def have been cloned. For each successor block,
   942   // get the clone of the use, and make its input the clone of the def
   943   // found in that block.
   945   uint use_idx = blk->find_node(use);
   946   uint offset_idx = use_idx - beg;
   947   for( uint k = 0; k < blk->_num_succs; k++ ) {
   948     // Get clone in each successor block
   949     Block *sb = blk->_succs[k];
   950     Node *clone = sb->_nodes[offset_idx+1];
   951     assert( clone->Opcode() == use->Opcode(), "" );
   953     // Make use-clone reference the def-clone
   954     catch_cleanup_fix_all_inputs(clone, def, sb->_nodes[n_clone_idx]);
   955   }
   956 }
   958 //------------------------------catch_cleanup_inter_block---------------------
   959 // Fix all input edges in use that reference "def".  The use is in a different
   960 // block than the def.
   961 static void catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
   962   if( !use_blk ) return;        // Can happen if the use is a precedence edge
   964   Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, bbs, n_clone_idx);
   965   catch_cleanup_fix_all_inputs(use, def, new_def);
   966 }
   968 //------------------------------call_catch_cleanup-----------------------------
   969 // If we inserted any instructions between a Call and his CatchNode,
   970 // clone the instructions on all paths below the Catch.
   971 void Block::call_catch_cleanup(Block_Array &bbs) {
   973   // End of region to clone
   974   uint end = end_idx();
   975   if( !_nodes[end]->is_Catch() ) return;
   976   // Start of region to clone
   977   uint beg = end;
   978   while(!_nodes[beg-1]->is_MachProj() ||
   979         !_nodes[beg-1]->in(0)->is_MachCall() ) {
   980     beg--;
   981     assert(beg > 0,"Catch cleanup walking beyond block boundary");
   982   }
   983   // Range of inserted instructions is [beg, end)
   984   if( beg == end ) return;
   986   // Clone along all Catch output paths.  Clone area between the 'beg' and
   987   // 'end' indices.
   988   for( uint i = 0; i < _num_succs; i++ ) {
   989     Block *sb = _succs[i];
   990     // Clone the entire area; ignoring the edge fixup for now.
   991     for( uint j = end; j > beg; j-- ) {
   992       // It is safe here to clone a node with anti_dependence
   993       // since clones dominate on each path.
   994       Node *clone = _nodes[j-1]->clone();
   995       sb->_nodes.insert( 1, clone );
   996       bbs.map(clone->_idx,sb);
   997     }
   998   }
  1001   // Fixup edges.  Check the def-use info per cloned Node
  1002   for(uint i2 = beg; i2 < end; i2++ ) {
  1003     uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
  1004     Node *n = _nodes[i2];        // Node that got cloned
  1005     // Need DU safe iterator because of edge manipulation in calls.
  1006     Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
  1007     for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
  1008       out->push(n->fast_out(j1));
  1010     uint max = out->size();
  1011     for (uint j = 0; j < max; j++) {// For all users
  1012       Node *use = out->pop();
  1013       Block *buse = bbs[use->_idx];
  1014       if( use->is_Phi() ) {
  1015         for( uint k = 1; k < use->req(); k++ )
  1016           if( use->in(k) == n ) {
  1017             Node *fixup = catch_cleanup_find_cloned_def(bbs[buse->pred(k)->_idx], n, this, bbs, n_clone_idx);
  1018             use->set_req(k, fixup);
  1020       } else {
  1021         if (this == buse) {
  1022           catch_cleanup_intra_block(use, n, this, beg, n_clone_idx);
  1023         } else {
  1024           catch_cleanup_inter_block(use, buse, n, this, bbs, n_clone_idx);
  1027     } // End for all users
  1029   } // End of for all Nodes in cloned area
  1031   // Remove the now-dead cloned ops
  1032   for(uint i3 = beg; i3 < end; i3++ ) {
  1033     _nodes[beg]->disconnect_inputs(NULL);
  1034     _nodes.remove(beg);
  1037   // If the successor blocks have a CreateEx node, move it back to the top
  1038   for(uint i4 = 0; i4 < _num_succs; i4++ ) {
  1039     Block *sb = _succs[i4];
  1040     uint new_cnt = end - beg;
  1041     // Remove any newly created, but dead, nodes.
  1042     for( uint j = new_cnt; j > 0; j-- ) {
  1043       Node *n = sb->_nodes[j];
  1044       if (n->outcnt() == 0 &&
  1045           (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
  1046         n->disconnect_inputs(NULL);
  1047         sb->_nodes.remove(j);
  1048         new_cnt--;
  1051     // If any newly created nodes remain, move the CreateEx node to the top
  1052     if (new_cnt > 0) {
  1053       Node *cex = sb->_nodes[1+new_cnt];
  1054       if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
  1055         sb->_nodes.remove(1+new_cnt);
  1056         sb->_nodes.insert(1,cex);

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