src/edu/berkeley/sbp/GSS.java

   1 // Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
   2
   3 package edu.berkeley.sbp;
   4 import edu.berkeley.sbp.*;
   5 import edu.berkeley.sbp.util.*;
   6 import edu.berkeley.sbp.Parser.Table.*;
   7 import edu.berkeley.sbp.Sequence.Position;
   8 import java.io.*;
   9 import java.util.*;
  10 import java.lang.reflect.*;
  11
  12 /** implements Tomita's Graph Structured Stack */
  13 class GSS {
  14
  15     public static Queue<Node> removals = new LinkedList<Node>();
  16
  17     static String note = "";
  18     static int single_newnode = 0;
  19     static int toplevel_reductions = 0;
  20     static int multi_newnode = 0;
  21     static int waiting_newnode = 0;
  22     static int shifts = 0;
  23
  24     static int count = 0;
  25     static int reductions = 0;
  26     int resets = 0;
  27     int waits = 0;
  28
  29     Input input;
  30
  31     public GSS(Input input) { this.input = input; }
  32
  33     private Node[] reducing_list = null;
  34
  35     // FIXME: right now, these are the performance bottleneck
  36     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  37     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  38     HashMapBag<Integer,Sequence>       lastperformed   = new HashMapBag<Integer,Sequence>();
  39     HashMapBag<Integer,Sequence>       expected        = new HashMapBag<Integer,Sequence>();
  40
  41     /** FIXME */
  42     Forest.Many finalResult;
  43
  44     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  45     class Phase<Tok> implements Invokable<State, Forest, Node>, IntegerMappable, GraphViz.ToGraphViz, Iterable<Node> {
  46
  47         public int pos() { return pos; }
  48         public boolean closed() { return closed; }
  49         public Tok token() { return token; }
  50
  51         public Iterator<Node> iterator() { return hash.iterator(); }
  52         public void invoke(State st, Forest result, Node n) {
  53             shifts++;
  54             good |= next.newNode(n, result, st, false);
  55         }
  56
  57         /** the token immediately after this phase */
  58         final Tok token;
  59
  60         private final int pos;
  61
  62         boolean reducing;
  63         public IntPairMap<Node> hash;  /* ALLOC */
  64         private boolean closed;
  65         private boolean good;
  66         private Phase next = null;
  67         private Phase prev;
  68         private Input.Location location;
  69         private Input.Location nextLocation;
  70         private Input.Location prevLocation;
  71
  72         public final Parser parser;
  73
  74         private Forest forest;
  75
  76         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location,
  77                      Input.Location nextLocation, Forest forest) throws ParseFailed {
  78             this.prevLocation = prev==null ? location : prev.getLocation();
  79             this.prev = prev;
  80             this.forest = forest;
  81             this.parser = parser;
  82             this.pos = previous==null ? 0 : previous.pos+1;
  83             this.token = token;
  84             this.location = location;
  85             this.nextLocation = nextLocation;
  86             performed.clear();
  87             reset();
  88         }
  89
  90         public void reset() throws ParseFailed {
  91             waiting.clear();
  92             expected.clear();
  93             lastperformed.clear();
  94             lastperformed.addAll(performed);
  95             performed.clear();
  96             hash = new IntPairMap<Node>();
  97             reset = false;
  98             good = false;
  99             closed = false;
 100             reducing = false;
 101             finalResult = null;
 102             if (prev != null) prev.shift(this, forest);
 103         }
 104
 105
 106         public boolean isDone() throws ParseFailed {
 107             if (token != null) return false;
 108             if (token==null && finalResult==null)
 109                 ParseFailed.error("unexpected end of file",
 110                                   getLocation(),
 111                                   token,
 112                                   hash.values(),
 113                                   getLocation().createRegion(getLocation()),
 114                                   input,
 115                                   GSS.this);
 116             return true;
 117         }
 118
 119         public Input.Location getPrevLocation() { return prevLocation; }
 120         public Input.Location getLocation() { return location; }
 121         public Input.Region   getRegion() { return getPrevLocation().createRegion(getLocation()); }
 122         public Input.Location getNextLocation() { return nextLocation; }
 123
 124         /** add a new node (merging with existing nodes if possible)
 125          *  @param parent             the parent of the new node
 126          *  @param result             the SPPF result corresponding to the new node
 127          *  @param state              the state that the new node is in
 128          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 129          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 130          */
 131         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 132             Node p = hash.get(state, parent==null?null:parent.phase());
 133             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 134             else            return newNode3(parent, pending, state, fromEmptyReduction);
 135         }
 136         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 137             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 138             Sequence owner = reduction==null ? null : reduction.owner();
 139             if (reduction!=null) {
 140                 if (owner.hates!=null) {
 141                     for (Sequence s : performed.getAll(pos))
 142                         if (owner.hates.contains(s))
 143                             return;
 144                     for (Sequence s : lastperformed.getAll(pos))
 145                         if (owner.hates.contains(s)) {
 146                             //System.out.println("now expecting ["+pos+"] => " + s);
 147                             expected.add(pos, s);
 148                             return;
 149                         }
 150                 }
 151                 if (owner.needs != null)
 152                     for(Sequence s : owner.needs)
 153                         if (!performed.contains(pos, s)) {
 154                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 155                             return;
 156                         }
 157                 if (!performed.contains(pos, owner)) {
 158                     performed.add(pos, owner);
 159                     if (owner.hated != null)
 160                         for(Sequence seq : owner.hated)
 161                             if (performed.contains(pos, seq)) {
 162                                 performed.remove(pos, seq);
 163                                 reset = true;
 164                             }
 165                 }
 166             }
 167             newNode(parent, pending, state, fromEmptyReduction);
 168             if (reduction != null) {
 169                 boolean redo = true;
 170                 while(redo) {
 171                     redo = false;
 172                     for(Waiting w : waiting.getAll(owner)) {
 173                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 174                             waiting.remove(owner, w);
 175                             w.perform();
 176                             redo = true;
 177                             break;
 178                         }
 179                     }
 180                 }
 181             }
 182         }
 183
 184         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 185             if (p.merge(parent, pending)) return true;
 186             p.addParent(parent, true);
 187             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 188             return true;
 189         }
 190
 191         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 192             do {
 193                 if (token != null && state.canShift(token)) break;
 194                 if (state.isAccepting()) break;
 195                 if (token==null) break;
 196                 if (!state.canReduce(token)) return false;
 197                 //if (count > 1) break;
 198                 //if (r.numPop == 0) break;
 199                 //r.reduce(pending, parent, null, Phase.this, null);
 200                 //return;
 201             } while(false);
 202
 203             Node n = new Node(Phase.this, parent, pending, state);  // ALLOC
 204             if (reducing) {
 205                 n.performEmptyReductions();
 206                 if (!fromEmptyReduction) n.performReductions(parent);
 207             }
 208             return true;
 209         }
 210
 211         public LinkedList<Node> reductionQueue = new LinkedList<Node>();
 212
 213         /** perform all reduction operations */
 214         public void reduce() throws ParseFailed {
 215             try {
 216                 reducing = true;
 217                 if (reducing_list==null || reducing_list.length < hash.size())
 218                     reducing_list = new Node[hash.size() * 4];
 219                 hash.toArray(reducing_list);
 220                 int num = hash.size();
 221                 for(int i=0; i<num; i++) {
 222                     Node n = reducing_list[i];
 223                     n.performEmptyReductions();
 224                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 225                 }
 226                 for(int i=0; i<num; i++) {
 227                     reductionQueue.add(reducing_list[i]);
 228                     reducing_list[i] = null;
 229                 }
 230                 while(!reductionQueue.isEmpty()) {
 231                     reductionQueue.remove().performReductions();
 232                 }
 233                 if (reset) {
 234                     reset = false;
 235                     resets++;
 236                     throw new Reset();
 237                 }
 238                 for(int i : expected)
 239                     for(Sequence s : expected.getAll(i))
 240                         if (!performed.contains(i, s)) {
 241                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 242                             resets++;
 243                             throw new Reset();
 244                         }
 245             } catch (Reset r) {
 246                 reset();
 247                 reduce();
 248             }
 249             count = 0;
 250         }
 251
 252         private boolean reset = false;
 253         class Reset extends RuntimeException { }
 254
 255         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 256         public void shift(Phase next, Forest result) throws ParseFailed {
 257             // this massively improves GC performance
 258             if (prev!=null && parser.helpgc) {
 259                 //prev.hash = null;
 260                 //System.out.println("\r" + /*shifts + " " + */ single_newnode /*+ "/"+multi_newnode + " " + waiting_newnode*/);
 261                 //System.out.println("\r" + shifts + " " + note);
 262                 //System.out.println("\r" + shifts);
 263                 //System.out.println("\r" + toplevel_reductions);
 264                 //System.out.println("\r" + multi_newnode);
 265                 single_newnode = 0;
 266                 note = "";
 267                 multi_newnode = 0;
 268                 toplevel_reductions = 0;
 269                 waiting_newnode = 0;
 270                 shifts = 0;
 271             }
 272             this.next = next;
 273             closed = true;
 274             Forest res = null;
 275             boolean ok = false;
 276             int count = 0;
 277             for(Node n : hash.values()) {
 278                 if (token == null && n.state().isAccepting()) {
 279                     if (finalResult==null) finalResult = new Forest.Many();
 280                     for(Object f : n.results())
 281                         finalResult.merge((Forest)f);
 282                 }
 283                 if (token == null) continue;
 284                 n.state().invokeShifts(token, this, result, n);
 285             }
 286             //System.out.println(next.hash.size());
 287             if (!good && token!=null)
 288                 ParseFailed.error("unexpected character",
 289                                   getLocation(),
 290                                   token,
 291                                   hash.values(),
 292                                   getRegion(),
 293                                   input,
 294                                   GSS.this);
 295
 296             if (token==null && finalResult==null)
 297                 ParseFailed.error("unexpected end of file",
 298                                   getLocation(),
 299                                   token,
 300                                   hash.values(),
 301                                   getLocation().createRegion(getLocation()),
 302                                   input,
 303                                   GSS.this);
 304         }
 305
 306
 307         class Waiting {
 308             Node parent;
 309             Forest pending;
 310             State state;
 311             boolean fromEmptyReduction;
 312             Position reduction;
 313             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 314                 waits++;
 315                 this.parent = parent;
 316                 this.pending = pending;
 317                 this.state = state;
 318                 this.fromEmptyReduction = fromEmptyReduction;
 319                 this.reduction = reduction;
 320             }
 321             public void perform() {
 322                 //System.out.println("performing: " + reduction.position);
 323                 waiting_newnode++;
 324                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 325             }
 326         }
 327
 328
 329         public int toInt() { return pos+1; }
 330         public int size() { return hash==null ? 0 : hash.size(); }
 331
 332         // GraphViz //////////////////////////////////////////////////////////////////////////////
 333
 334         public GraphViz.Node toGraphViz(GraphViz gv) {
 335             if (gv.hasNode(this)) return gv.createNode(this);
 336             GraphViz.Group g = gv.createGroup(this);
 337             g.label = "Phase " + pos;
 338             g.color = "gray";
 339             g.cluster = true;
 340             return g;
 341         }
 342         public boolean isTransparent() { return false; }
 343         public boolean isHidden() { return false; }
 344
 345     }
 346
 347 }