jdk8-mips64-public/hotspot: src/share/vm/opto/ifg.cpp@98cb887364d3 (annotated)

src/share/vm/opto/ifg.cpp@98cb887364d3 (annotated)

src/share/vm/opto/ifg.cpp

Fri, 27 Feb 2009 13:27:09 -0800

author: twisti
date: Fri, 27 Feb 2009 13:27:09 -0800
changeset 1040: 98cb887364d3
parent 1001: 91263420e1c6
child 1063: 7bb995fbd3c0
permissions: -rw-r--r--

6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never

 /*
  * Copyright 1998-2008 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_ifg.cpp.incl"
 #define EXACT_PRESSURE 1
 //=============================================================================
 //------------------------------IFG--------------------------------------------
 PhaseIFG::PhaseIFG( Arena *arena ) : Phase(Interference_Graph), _arena(arena) {
 }
 //------------------------------init-------------------------------------------
 void PhaseIFG::init( uint maxlrg ) {
   _maxlrg = maxlrg;
   _yanked = new (_arena) VectorSet(_arena);
   _is_square = false;
   // Make uninitialized adjacency lists
   _adjs = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*maxlrg);
   // Also make empty live range structures
   _lrgs = (LRG *)_arena->Amalloc( maxlrg * sizeof(LRG) );
   memset(_lrgs,0,sizeof(LRG)*maxlrg);
   // Init all to empty
   for( uint i = 0; i < maxlrg; i++ ) {
     _adjs[i].initialize(maxlrg);
     _lrgs[i].Set_All();
   }
 }
 //------------------------------add--------------------------------------------
 // Add edge between vertices a & b.  These are sorted (triangular matrix),
 // then the smaller number is inserted in the larger numbered array.
 int PhaseIFG::add_edge( uint a, uint b ) {
   lrgs(a).invalid_degree();
   lrgs(b).invalid_degree();
   // Sort a and b, so that a is bigger
   assert( !_is_square, "only on triangular" );
   if( a < b ) { uint tmp = a; a = b; b = tmp; }
   return _adjs[a].insert( b );
 }
 //------------------------------add_vector-------------------------------------
 // Add an edge between 'a' and everything in the vector.
 void PhaseIFG::add_vector( uint a, IndexSet *vec ) {
   // IFG is triangular, so do the inserts where 'a' < 'b'.
   assert( !_is_square, "only on triangular" );
   IndexSet *adjs_a = &_adjs[a];
   if( !vec->count() ) return;
   IndexSetIterator elements(vec);
   uint neighbor;
   while ((neighbor = elements.next()) != 0) {
     add_edge( a, neighbor );
   }
 }
 //------------------------------test-------------------------------------------
 // Is there an edge between a and b?
 int PhaseIFG::test_edge( uint a, uint b ) const {
   // Sort a and b, so that a is larger
   assert( !_is_square, "only on triangular" );
   if( a < b ) { uint tmp = a; a = b; b = tmp; }
   return _adjs[a].member(b);
 }
 //------------------------------SquareUp---------------------------------------
 // Convert triangular matrix to square matrix
 void PhaseIFG::SquareUp() {
   assert( !_is_square, "only on triangular" );
   // Simple transpose
   for( uint i = 0; i < _maxlrg; i++ ) {
     IndexSetIterator elements(&_adjs[i]);
     uint datum;
     while ((datum = elements.next()) != 0) {
       _adjs[datum].insert( i );
     }
   }
   _is_square = true;
 }
 //------------------------------Compute_Effective_Degree-----------------------
 // Compute effective degree in bulk
 void PhaseIFG::Compute_Effective_Degree() {
   assert( _is_square, "only on square" );
   for( uint i = 0; i < _maxlrg; i++ )
     lrgs(i).set_degree(effective_degree(i));
 }
 //------------------------------test_edge_sq-----------------------------------
 int PhaseIFG::test_edge_sq( uint a, uint b ) const {
   assert( _is_square, "only on square" );
   // Swap, so that 'a' has the lesser count.  Then binary search is on
   // the smaller of a's list and b's list.
   if( neighbor_cnt(a) > neighbor_cnt(b) ) { uint tmp = a; a = b; b = tmp; }
   //return _adjs[a].unordered_member(b);
   return _adjs[a].member(b);
 }
 //------------------------------Union------------------------------------------
 // Union edges of B into A
 void PhaseIFG::Union( uint a, uint b ) {
   assert( _is_square, "only on square" );
   IndexSet *A = &_adjs[a];
   IndexSetIterator b_elements(&_adjs[b]);
   uint datum;
   while ((datum = b_elements.next()) != 0) {
     if(A->insert(datum)) {
       _adjs[datum].insert(a);
       lrgs(a).invalid_degree();
       lrgs(datum).invalid_degree();
     }
   }
 }
 //------------------------------remove_node------------------------------------
 // Yank a Node and all connected edges from the IFG.  Return a
 // list of neighbors (edges) yanked.
 IndexSet *PhaseIFG::remove_node( uint a ) {
   assert( _is_square, "only on square" );
   assert( !_yanked->test(a), "" );
   _yanked->set(a);
   // I remove the LRG from all neighbors.
   IndexSetIterator elements(&_adjs[a]);
   LRG &lrg_a = lrgs(a);
   uint datum;
   while ((datum = elements.next()) != 0) {
     _adjs[datum].remove(a);
     lrgs(datum).inc_degree( -lrg_a.compute_degree(lrgs(datum)) );
   }
   return neighbors(a);
 }
 //------------------------------re_insert--------------------------------------
 // Re-insert a yanked Node.
 void PhaseIFG::re_insert( uint a ) {
   assert( _is_square, "only on square" );
   assert( _yanked->test(a), "" );
   (*_yanked) >>= a;
   IndexSetIterator elements(&_adjs[a]);
   uint datum;
   while ((datum = elements.next()) != 0) {
     _adjs[datum].insert(a);
     lrgs(datum).invalid_degree();
   }
 }
 //------------------------------compute_degree---------------------------------
 // Compute the degree between 2 live ranges.  If both live ranges are
 // aligned-adjacent powers-of-2 then we use the MAX size.  If either is
 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to
 // MULTIPLY the sizes.  Inspect Brigg's thesis on register pairs to see why
 // this is so.
 int LRG::compute_degree( LRG &l ) const {
   int tmp;
   int num_regs = _num_regs;
   int nregs = l.num_regs();
   tmp =  (_fat_proj || l._fat_proj)     // either is a fat-proj?
     ? (num_regs * nregs)                // then use product
     : MAX2(num_regs,nregs);             // else use max
   return tmp;
 }
 //------------------------------effective_degree-------------------------------
 // Compute effective degree for this live range.  If both live ranges are
 // aligned-adjacent powers-of-2 then we use the MAX size.  If either is
 // mis-aligned (or for Fat-Projections, not-adjacent) then we have to
 // MULTIPLY the sizes.  Inspect Brigg's thesis on register pairs to see why
 // this is so.
 int PhaseIFG::effective_degree( uint lidx ) const {
   int eff = 0;
   int num_regs = lrgs(lidx).num_regs();
   int fat_proj = lrgs(lidx)._fat_proj;
   IndexSet *s = neighbors(lidx);
   IndexSetIterator elements(s);
   uint nidx;
   while((nidx = elements.next()) != 0) {
     LRG &lrgn = lrgs(nidx);
     int nregs = lrgn.num_regs();
     eff += (fat_proj || lrgn._fat_proj) // either is a fat-proj?
       ? (num_regs * nregs)              // then use product
       : MAX2(num_regs,nregs);           // else use max
   }
   return eff;
 }
 #ifndef PRODUCT
 //------------------------------dump-------------------------------------------
 void PhaseIFG::dump() const {
   tty->print_cr("-- Interference Graph --%s--",
                 _is_square ? "square" : "triangular" );
   if( _is_square ) {
     for( uint i = 0; i < _maxlrg; i++ ) {
       tty->print( (*_yanked)[i] ? "XX " : "  ");
       tty->print("L%d: { ",i);
       IndexSetIterator elements(&_adjs[i]);
       uint datum;
       while ((datum = elements.next()) != 0) {
         tty->print("L%d ", datum);
       }
       tty->print_cr("}");
     }
     return;
   }
   // Triangular
   for( uint i = 0; i < _maxlrg; i++ ) {
     uint j;
     tty->print( (*_yanked)[i] ? "XX " : "  ");
     tty->print("L%d: { ",i);
     for( j = _maxlrg; j > i; j-- )
       if( test_edge(j - 1,i) ) {
         tty->print("L%d ",j - 1);
       }
     tty->print("| ");
     IndexSetIterator elements(&_adjs[i]);
     uint datum;
     while ((datum = elements.next()) != 0) {
       tty->print("L%d ", datum);
     }
     tty->print("}\n");
   }
   tty->print("\n");
 }
 //------------------------------stats------------------------------------------
 void PhaseIFG::stats() const {
   ResourceMark rm;
   int *h_cnt = NEW_RESOURCE_ARRAY(int,_maxlrg*2);
   memset( h_cnt, 0, sizeof(int)*_maxlrg*2 );
   uint i;
   for( i = 0; i < _maxlrg; i++ ) {
     h_cnt[neighbor_cnt(i)]++;
   }
   tty->print_cr("--Histogram of counts--");
   for( i = 0; i < _maxlrg*2; i++ )
     if( h_cnt[i] )
       tty->print("%d/%d ",i,h_cnt[i]);
   tty->print_cr("");
 }
 //------------------------------verify-----------------------------------------
 void PhaseIFG::verify( const PhaseChaitin *pc ) const {
   // IFG is square, sorted and no need for Find
   for( uint i = 0; i < _maxlrg; i++ ) {
     assert(!((*_yanked)[i]) || !neighbor_cnt(i), "Is removed completely" );
     IndexSet *set = &_adjs[i];
     IndexSetIterator elements(set);
     uint idx;
     uint last = 0;
     while ((idx = elements.next()) != 0) {
       assert( idx != i, "Must have empty diagonal");
       assert( pc->Find_const(idx) == idx, "Must not need Find" );
       assert( _adjs[idx].member(i), "IFG not square" );
       assert( !(*_yanked)[idx], "No yanked neighbors" );
       assert( last < idx, "not sorted increasing");
       last = idx;
     }
     assert( !lrgs(i)._degree_valid ||
             effective_degree(i) == lrgs(i).degree(), "degree is valid but wrong" );
   }
 }
 #endif
 //------------------------------interfere_with_live----------------------------
 // Interfere this register with everything currently live.  Use the RegMasks
 // to trim the set of possible interferences. Return a count of register-only
 // interferences as an estimate of register pressure.
 void PhaseChaitin::interfere_with_live( uint r, IndexSet *liveout ) {
   uint retval = 0;
   // Interfere with everything live.
   const RegMask &rm = lrgs(r).mask();
   // Check for interference by checking overlap of regmasks.
   // Only interfere if acceptable register masks overlap.
   IndexSetIterator elements(liveout);
   uint l;
   while( (l = elements.next()) != 0 )
     if( rm.overlap( lrgs(l).mask() ) )
       _ifg->add_edge( r, l );
 }
 //------------------------------build_ifg_virtual------------------------------
 // Actually build the interference graph.  Uses virtual registers only, no
 // physical register masks.  This allows me to be very aggressive when
 // coalescing copies.  Some of this aggressiveness will have to be undone
 // later, but I'd rather get all the copies I can now (since unremoved copies
 // at this point can end up in bad places).  Copies I re-insert later I have
 // more opportunity to insert them in low-frequency locations.
 void PhaseChaitin::build_ifg_virtual( ) {
   // For all blocks (in any order) do...
   for( uint i=0; i<_cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     IndexSet *liveout = _live->live(b);
     // The IFG is built by a single reverse pass over each basic block.
     // Starting with the known live-out set, we remove things that get
     // defined and add things that become live (essentially executing one
     // pass of a standard LIVE analysis). Just before a Node defines a value
     // (and removes it from the live-ness set) that value is certainly live.
     // The defined value interferes with everything currently live.  The
     // value is then removed from the live-ness set and it's inputs are
     // added to the live-ness set.
     for( uint j = b->end_idx() + 1; j > 1; j-- ) {
       Node *n = b->_nodes[j-1];
       // Get value being defined
       uint r = n2lidx(n);
       // Some special values do not allocate
       if( r ) {
         // Remove from live-out set
         liveout->remove(r);
         // Copies do not define a new value and so do not interfere.
         // Remove the copies source from the liveout set before interfering.
         uint idx = n->is_Copy();
         if( idx ) liveout->remove( n2lidx(n->in(idx)) );
         // Interfere with everything live
         interfere_with_live( r, liveout );
       }
       // Make all inputs live
       if( !n->is_Phi() ) {      // Phi function uses come from prior block
         for( uint k = 1; k < n->req(); k++ )
           liveout->insert( n2lidx(n->in(k)) );
       }
       // 2-address instructions always have the defined value live
       // on entry to the instruction, even though it is being defined
       // by the instruction.  We pretend a virtual copy sits just prior
       // to the instruction and kills the src-def'd register.
       // In other words, for 2-address instructions the defined value
       // interferes with all inputs.
       uint idx;
       if( n->is_Mach() && (idx = n->as_Mach()->two_adr()) ) {
         const MachNode *mach = n->as_Mach();
         // Sometimes my 2-address ADDs are commuted in a bad way.
         // We generally want the USE-DEF register to refer to the
         // loop-varying quantity, to avoid a copy.
         uint op = mach->ideal_Opcode();
         // Check that mach->num_opnds() == 3 to ensure instruction is
         // not subsuming constants, effectively excludes addI_cin_imm
         // Can NOT swap for instructions like addI_cin_imm since it
         // is adding zero to yhi + carry and the second ideal-input
         // points to the result of adding low-halves.
         // Checking req() and num_opnds() does NOT distinguish addI_cout from addI_cout_imm
         if( (op == Op_AddI && mach->req() == 3 && mach->num_opnds() == 3) &&
             n->in(1)->bottom_type()->base() == Type::Int &&
             // See if the ADD is involved in a tight data loop the wrong way
             n->in(2)->is_Phi() &&
             n->in(2)->in(2) == n ) {
           Node *tmp = n->in(1);
           n->set_req( 1, n->in(2) );
           n->set_req( 2, tmp );
         }
         // Defined value interferes with all inputs
         uint lidx = n2lidx(n->in(idx));
         for( uint k = 1; k < n->req(); k++ ) {
           uint kidx = n2lidx(n->in(k));
           if( kidx != lidx )
             _ifg->add_edge( r, kidx );
         }
       }
     } // End of forall instructions in block
   } // End of forall blocks
 }
 //------------------------------count_int_pressure-----------------------------
 uint PhaseChaitin::count_int_pressure( IndexSet *liveout ) {
   IndexSetIterator elements(liveout);
   uint lidx;
   uint cnt = 0;
   while ((lidx = elements.next()) != 0) {
     if( lrgs(lidx).mask().is_UP() &&
         lrgs(lidx).mask_size() &&
         !lrgs(lidx)._is_float &&
         lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) )
       cnt += lrgs(lidx).reg_pressure();
   }
   return cnt;
 }
 //------------------------------count_float_pressure---------------------------
 uint PhaseChaitin::count_float_pressure( IndexSet *liveout ) {
   IndexSetIterator elements(liveout);
   uint lidx;
   uint cnt = 0;
   while ((lidx = elements.next()) != 0) {
     if( lrgs(lidx).mask().is_UP() &&
         lrgs(lidx).mask_size() &&
         lrgs(lidx)._is_float )
       cnt += lrgs(lidx).reg_pressure();
   }
   return cnt;
 }
 //------------------------------lower_pressure---------------------------------
 // Adjust register pressure down by 1.  Capture last hi-to-low transition,
 static void lower_pressure( LRG *lrg, uint where, Block *b, uint *pressure, uint *hrp_index ) {
   if( lrg->mask().is_UP() && lrg->mask_size() ) {
     if( lrg->_is_float ) {
       pressure[1] -= lrg->reg_pressure();
       if( pressure[1] == (uint)FLOATPRESSURE ) {
         hrp_index[1] = where;
 #ifdef EXACT_PRESSURE
       if( pressure[1] > b->_freg_pressure )
         b->_freg_pressure = pressure[1]+1;
 #else
         b->_freg_pressure = (uint)FLOATPRESSURE+1;
 #endif
       }
     } else if( lrg->mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
       pressure[0] -= lrg->reg_pressure();
       if( pressure[0] == (uint)INTPRESSURE   ) {
         hrp_index[0] = where;
 #ifdef EXACT_PRESSURE
       if( pressure[0] > b->_reg_pressure )
         b->_reg_pressure = pressure[0]+1;
 #else
         b->_reg_pressure = (uint)INTPRESSURE+1;
 #endif
       }
     }
   }
 }
 //------------------------------build_ifg_physical-----------------------------
 // Build the interference graph using physical registers when available.
 // That is, if 2 live ranges are simultaneously alive but in their acceptable
 // register sets do not overlap, then they do not interfere.
 uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) {
   NOT_PRODUCT( Compile::TracePhase t3("buildIFG", &_t_buildIFGphysical, TimeCompiler); )
   uint spill_reg = LRG::SPILL_REG;
   uint must_spill = 0;
   // For all blocks (in any order) do...
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     // Clone (rather than smash in place) the liveout info, so it is alive
     // for the "collect_gc_info" phase later.
     IndexSet liveout(_live->live(b));
     uint last_inst = b->end_idx();
     // Compute first nonphi node index
     uint first_inst;
     for( first_inst = 1; first_inst < last_inst; first_inst++ )
       if( !b->_nodes[first_inst]->is_Phi() )
         break;
     // Spills could be inserted before CreateEx node which should be
     // first instruction in block after Phis. Move CreateEx up.
     for( uint insidx = first_inst; insidx < last_inst; insidx++ ) {
       Node *ex = b->_nodes[insidx];
       if( ex->is_SpillCopy() ) continue;
       if( insidx > first_inst && ex->is_Mach() &&
           ex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
         // If the CreateEx isn't above all the MachSpillCopies
         // then move it to the top.
         b->_nodes.remove(insidx);
         b->_nodes.insert(first_inst, ex);
       }
       // Stop once a CreateEx or any other node is found
       break;
     }
     // Reset block's register pressure values for each ifg construction
     uint pressure[2], hrp_index[2];
     pressure[0] = pressure[1] = 0;
     hrp_index[0] = hrp_index[1] = last_inst+1;
     b->_reg_pressure = b->_freg_pressure = 0;
     // Liveout things are presumed live for the whole block.  We accumulate
     // 'area' accordingly.  If they get killed in the block, we'll subtract
     // the unused part of the block from the area.
     int inst_count = last_inst - first_inst;
     double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
     assert(!(cost < 0.0), "negative spill cost" );
     IndexSetIterator elements(&liveout);
     uint lidx;
     while ((lidx = elements.next()) != 0) {
       LRG &lrg = lrgs(lidx);
       lrg._area += cost;
       // Compute initial register pressure
       if( lrg.mask().is_UP() && lrg.mask_size() ) {
         if( lrg._is_float ) {   // Count float pressure
           pressure[1] += lrg.reg_pressure();
 #ifdef EXACT_PRESSURE
           if( pressure[1] > b->_freg_pressure )
             b->_freg_pressure = pressure[1];
 #endif
           // Count int pressure, but do not count the SP, flags
         } else if( lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
           pressure[0] += lrg.reg_pressure();
 #ifdef EXACT_PRESSURE
           if( pressure[0] > b->_reg_pressure )
             b->_reg_pressure = pressure[0];
 #endif
         }
       }
     }
     assert( pressure[0] == count_int_pressure  (&liveout), "" );
     assert( pressure[1] == count_float_pressure(&liveout), "" );
     // The IFG is built by a single reverse pass over each basic block.
     // Starting with the known live-out set, we remove things that get
     // defined and add things that become live (essentially executing one
     // pass of a standard LIVE analysis).  Just before a Node defines a value
     // (and removes it from the live-ness set) that value is certainly live.
     // The defined value interferes with everything currently live.  The
     // value is then removed from the live-ness set and it's inputs are added
     // to the live-ness set.
     uint j;
     for( j = last_inst + 1; j > 1; j-- ) {
       Node *n = b->_nodes[j - 1];
       // Get value being defined
       uint r = n2lidx(n);
       // Some special values do not allocate
       if( r ) {
         // A DEF normally costs block frequency; rematerialized values are
         // removed from the DEF sight, so LOWER costs here.
         lrgs(r)._cost += n->rematerialize() ? 0 : b->_freq;
         // If it is not live, then this instruction is dead.  Probably caused
         // by spilling and rematerialization.  Who cares why, yank this baby.
         if( !liveout.member(r) && n->Opcode() != Op_SafePoint ) {
           Node *def = n->in(0);
           if( !n->is_Proj() ||
               // Could also be a flags-projection of a dead ADD or such.
               (n2lidx(def) && !liveout.member(n2lidx(def)) ) ) {
             b->_nodes.remove(j - 1);
             if( lrgs(r)._def == n ) lrgs(r)._def = 0;
             n->disconnect_inputs(NULL);
             _cfg._bbs.map(n->_idx,NULL);
             n->replace_by(C->top());
             // Since yanking a Node from block, high pressure moves up one
             hrp_index[0]--;
             hrp_index[1]--;
             continue;
           }
           // Fat-projections kill many registers which cannot be used to
           // hold live ranges.
           if( lrgs(r)._fat_proj ) {
             // Count the int-only registers
             RegMask itmp = lrgs(r).mask();
             itmp.AND(*Matcher::idealreg2regmask[Op_RegI]);
             int iregs = itmp.Size();
 #ifdef EXACT_PRESSURE
             if( pressure[0]+iregs > b->_reg_pressure )
               b->_reg_pressure = pressure[0]+iregs;
 #endif
             if( pressure[0]       <= (uint)INTPRESSURE &&
                 pressure[0]+iregs >  (uint)INTPRESSURE ) {
 #ifndef EXACT_PRESSURE
               b->_reg_pressure = (uint)INTPRESSURE+1;
 #endif
               hrp_index[0] = j-1;
             }
             // Count the float-only registers
             RegMask ftmp = lrgs(r).mask();
             ftmp.AND(*Matcher::idealreg2regmask[Op_RegD]);
             int fregs = ftmp.Size();
 #ifdef EXACT_PRESSURE
             if( pressure[1]+fregs > b->_freg_pressure )
               b->_freg_pressure = pressure[1]+fregs;
 #endif
             if( pressure[1]       <= (uint)FLOATPRESSURE &&
                 pressure[1]+fregs >  (uint)FLOATPRESSURE ) {
 #ifndef EXACT_PRESSURE
               b->_freg_pressure = (uint)FLOATPRESSURE+1;
 #endif
               hrp_index[1] = j-1;
             }
           }
         } else {                // Else it is live
           // A DEF also ends 'area' partway through the block.
           lrgs(r)._area -= cost;
           assert(!(lrgs(r)._area < 0.0), "negative spill area" );
           // Insure high score for immediate-use spill copies so they get a color
           if( n->is_SpillCopy()
               && lrgs(r).is_singledef()        // MultiDef live range can still split
               && n->outcnt() == 1              // and use must be in this block
               && _cfg._bbs[n->unique_out()->_idx] == b ) {
             // All single-use MachSpillCopy(s) that immediately precede their
             // use must color early.  If a longer live range steals their
             // color, the spill copy will split and may push another spill copy
             // further away resulting in an infinite spill-split-retry cycle.
             // Assigning a zero area results in a high score() and a good
             // location in the simplify list.
             //
             Node *single_use = n->unique_out();
             assert( b->find_node(single_use) >= j, "Use must be later in block");
             // Use can be earlier in block if it is a Phi, but then I should be a MultiDef
             // Find first non SpillCopy 'm' that follows the current instruction
             // (j - 1) is index for current instruction 'n'
             Node *m = n;
             for( uint i = j; i <= last_inst && m->is_SpillCopy(); ++i ) { m = b->_nodes[i]; }
             if( m == single_use ) {
               lrgs(r)._area = 0.0;
             }
           }
           // Remove from live-out set
           if( liveout.remove(r) ) {
             // Adjust register pressure.
             // Capture last hi-to-lo pressure transition
             lower_pressure( &lrgs(r), j-1, b, pressure, hrp_index );
             assert( pressure[0] == count_int_pressure  (&liveout), "" );
             assert( pressure[1] == count_float_pressure(&liveout), "" );
           }
           // Copies do not define a new value and so do not interfere.
           // Remove the copies source from the liveout set before interfering.
           uint idx = n->is_Copy();
           if( idx ) {
             uint x = n2lidx(n->in(idx));
             if( liveout.remove( x ) ) {
               lrgs(x)._area -= cost;
               // Adjust register pressure.
               lower_pressure( &lrgs(x), j-1, b, pressure, hrp_index );
               assert( pressure[0] == count_int_pressure  (&liveout), "" );
               assert( pressure[1] == count_float_pressure(&liveout), "" );
             }
           }
         } // End of if live or not
         // Interfere with everything live.  If the defined value must
         // go in a particular register, just remove that register from
         // all conflicting parties and avoid the interference.
         // Make exclusions for rematerializable defs.  Since rematerializable
         // DEFs are not bound but the live range is, some uses must be bound.
         // If we spill live range 'r', it can rematerialize at each use site
         // according to its bindings.
         const RegMask &rmask = lrgs(r).mask();
         if( lrgs(r).is_bound() && !(n->rematerialize()) && rmask.is_NotEmpty() ) {
           // Smear odd bits; leave only aligned pairs of bits.
           RegMask r2mask = rmask;
           r2mask.SmearToPairs();
           // Check for common case
           int r_size = lrgs(r).num_regs();
           OptoReg::Name r_reg = (r_size == 1) ? rmask.find_first_elem() : OptoReg::Physical;
           IndexSetIterator elements(&liveout);
           uint l;
           while ((l = elements.next()) != 0) {
             LRG &lrg = lrgs(l);
             // If 'l' must spill already, do not further hack his bits.
             // He'll get some interferences and be forced to spill later.
             if( lrg._must_spill ) continue;
             // Remove bound register(s) from 'l's choices
             RegMask old = lrg.mask();
             uint old_size = lrg.mask_size();
             // Remove the bits from LRG 'r' from LRG 'l' so 'l' no
             // longer interferes with 'r'.  If 'l' requires aligned
             // adjacent pairs, subtract out bit pairs.
             if( lrg.num_regs() == 2 && !lrg._fat_proj ) {
               lrg.SUBTRACT( r2mask );
               lrg.compute_set_mask_size();
             } else if( r_size != 1 ) {
               lrg.SUBTRACT( rmask );
               lrg.compute_set_mask_size();
             } else {            // Common case: size 1 bound removal
               if( lrg.mask().Member(r_reg) ) {
                 lrg.Remove(r_reg);
                 lrg.set_mask_size(lrg.mask().is_AllStack() ? 65535:old_size-1);
               }
             }
             // If 'l' goes completely dry, it must spill.
             if( lrg.not_free() ) {
               // Give 'l' some kind of reasonable mask, so he picks up
               // interferences (and will spill later).
               lrg.set_mask( old );
               lrg.set_mask_size(old_size);
               must_spill++;
               lrg._must_spill = 1;
               lrg.set_reg(OptoReg::Name(LRG::SPILL_REG));
             }
           }
         } // End of if bound
         // Now interference with everything that is live and has
         // compatible register sets.
         interfere_with_live(r,&liveout);
       } // End of if normal register-allocated value
       // Area remaining in the block
       inst_count--;
       cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
       // Make all inputs live
       if( !n->is_Phi() ) {      // Phi function uses come from prior block
         JVMState* jvms = n->jvms();
         uint debug_start = jvms ? jvms->debug_start() : 999999;
         // Start loop at 1 (skip control edge) for most Nodes.
         // SCMemProj's might be the sole use of a StoreLConditional.
         // While StoreLConditionals set memory (the SCMemProj use)
         // they also def flags; if that flag def is unused the
         // allocator sees a flag-setting instruction with no use of
         // the flags and assumes it's dead.  This keeps the (useless)
         // flag-setting behavior alive while also keeping the (useful)
         // memory update effect.
         for( uint k = ((n->Opcode() == Op_SCMemProj) ? 0:1); k < n->req(); k++ ) {
           Node *def = n->in(k);
           uint x = n2lidx(def);
           if( !x ) continue;
           LRG &lrg = lrgs(x);
           // No use-side cost for spilling debug info
           if( k < debug_start )
             // A USE costs twice block frequency (once for the Load, once
             // for a Load-delay).  Rematerialized uses only cost once.
             lrg._cost += (def->rematerialize() ? b->_freq : (b->_freq + b->_freq));
           // It is live now
           if( liveout.insert( x ) ) {
             // Newly live things assumed live from here to top of block
             lrg._area += cost;
             // Adjust register pressure
             if( lrg.mask().is_UP() && lrg.mask_size() ) {
               if( lrg._is_float ) {
                 pressure[1] += lrg.reg_pressure();
 #ifdef EXACT_PRESSURE
                 if( pressure[1] > b->_freg_pressure )
                   b->_freg_pressure = pressure[1];
 #endif
               } else if( lrg.mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
                 pressure[0] += lrg.reg_pressure();
 #ifdef EXACT_PRESSURE
                 if( pressure[0] > b->_reg_pressure )
                   b->_reg_pressure = pressure[0];
 #endif
               }
             }
             assert( pressure[0] == count_int_pressure  (&liveout), "" );
             assert( pressure[1] == count_float_pressure(&liveout), "" );
           }
           assert(!(lrg._area < 0.0), "negative spill area" );
         }
       }
     } // End of reverse pass over all instructions in block
     // If we run off the top of the block with high pressure and
     // never see a hi-to-low pressure transition, just record that
     // the whole block is high pressure.
     if( pressure[0] > (uint)INTPRESSURE   ) {
       hrp_index[0] = 0;
 #ifdef EXACT_PRESSURE
       if( pressure[0] > b->_reg_pressure )
         b->_reg_pressure = pressure[0];
 #else
       b->_reg_pressure = (uint)INTPRESSURE+1;
 #endif
     }
     if( pressure[1] > (uint)FLOATPRESSURE ) {
       hrp_index[1] = 0;
 #ifdef EXACT_PRESSURE
       if( pressure[1] > b->_freg_pressure )
         b->_freg_pressure = pressure[1];
 #else
       b->_freg_pressure = (uint)FLOATPRESSURE+1;
 #endif
     }
     // Compute high pressure indice; avoid landing in the middle of projnodes
     j = hrp_index[0];
     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
       Node *cur = b->_nodes[j];
       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
         j--;
         cur = b->_nodes[j];
       }
     }
     b->_ihrp_index = j;
     j = hrp_index[1];
     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
       Node *cur = b->_nodes[j];
       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
         j--;
         cur = b->_nodes[j];
       }
     }
     b->_fhrp_index = j;
 #ifndef PRODUCT
     // Gather Register Pressure Statistics
     if( PrintOptoStatistics ) {
       if( b->_reg_pressure > (uint)INTPRESSURE || b->_freg_pressure > (uint)FLOATPRESSURE )
         _high_pressure++;
       else
         _low_pressure++;
     }
 #endif
   } // End of for all blocks
   return must_spill;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/ifg.cpp@98cb887364d3 (annotated)

src/share/vm/opto/ifg.cpp