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     static int count = 0;
  16     static int shifts = 0;
  17     static int reductions = 0;
  18     int resets = 0;
  19     int waits = 0;
  20
  21     Input input;
  22
  23     public GSS(Input input) { this.input = input; }
  24
  25     private Phase.Node[] reducing_list = null;
  26
  27     // FIXME: right now, these are the performance bottleneck
  28     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  29     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  30     HashMapBag<Integer,Sequence>       lastperformed   = new HashMapBag<Integer,Sequence>();
  31     HashMapBag<Integer,Sequence>       expected        = new HashMapBag<Integer,Sequence>();
  32
  33     /** FIXME */
  34     Forest.Many finalResult;
  35
  36     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  37     class Phase<Tok> implements Invokable<State, Forest, Phase<Tok>.Node>, IntegerMappable, GraphViz.ToGraphViz, Iterable<Phase.Node> {
  38
  39         public Iterator<Phase.Node> iterator() { return hash.iterator(); }
  40         public void invoke(State st, Forest result, Node n) {
  41             shifts++;
  42             good |= next.newNode(n, result, st, false);
  43         }
  44
  45         /** the token immediately after this phase */
  46         final Tok token;
  47
  48         private final int pos;
  49
  50         boolean reducing;
  51         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  52         private boolean closed;
  53         private boolean good;
  54         private Phase next = null;
  55         private Phase prev;
  56         private Input.Location location;
  57         private Input.Location nextLocation;
  58         private Input.Location prevLocation;
  59
  60         public final Parser parser;
  61
  62         private Forest forest;
  63
  64         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location,
  65                      Input.Location nextLocation, Forest forest) throws ParseFailed {
  66             this.prevLocation = prev==null ? location : prev.getLocation();
  67             this.prev = prev;
  68             this.forest = forest;
  69             this.parser = parser;
  70             this.pos = previous==null ? 0 : previous.pos+1;
  71             this.token = token;
  72             this.location = location;
  73             this.nextLocation = nextLocation;
  74             performed.clear();
  75             reset();
  76         }
  77
  78         public void reset() throws ParseFailed {
  79             waiting.clear();
  80             expected.clear();
  81             lastperformed.clear();
  82             lastperformed.addAll(performed);
  83             performed.clear();
  84             hash = new IntPairMap<Phase.Node>();
  85             reset = false;
  86             good = false;
  87             closed = false;
  88             reducing = false;
  89             finalResult = null;
  90             if (prev != null) prev.shift(this, forest);
  91         }
  92
  93
  94         public boolean isDone() throws ParseFailed {
  95             if (token != null) return false;
  96             if (token==null && finalResult==null)
  97                 throw new ParseFailed(ParseFailed.error(("unexpected end of file\n"),
  98                                                         token, hash.values()),
  99                                       getLocation().createRegion(getLocation()), input);
 100             return true;
 101         }
 102
 103         public Input.Location getPrevLocation() { return prevLocation; }
 104         public Input.Location getLocation() { return location; }
 105         public Input.Region   getRegion() { return getPrevLocation().createRegion(getLocation()); }
 106         public Input.Location getNextLocation() { return nextLocation; }
 107
 108         /** add a new node (merging with existing nodes if possible)
 109          *  @param parent             the parent of the new node
 110          *  @param result             the SPPF result corresponding to the new node
 111          *  @param state              the state that the new node is in
 112          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 113          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 114          */
 115         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 116             Node p = hash.get(state, parent==null?null:parent.phase());
 117             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 118             else            return newNode3(parent, pending, state, fromEmptyReduction);
 119         }
 120         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 121             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 122             Sequence owner = reduction==null ? null : reduction.owner();
 123             if (reduction!=null) {
 124                 if (owner.hates!=null) {
 125                     for (Sequence s : performed.getAll(pos))
 126                         if (owner.hates.contains(s))
 127                             return;
 128                     for (Sequence s : lastperformed.getAll(pos))
 129                         if (owner.hates.contains(s)) {
 130                             //System.out.println("now expecting ["+pos+"] => " + s);
 131                             expected.add(pos, s);
 132                             return;
 133                         }
 134                 }
 135                 if (owner.needs != null)
 136                     for(Sequence s : owner.needs)
 137                         if (!performed.contains(pos, s)) {
 138                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 139                             return;
 140                         }
 141                 if (!performed.contains(pos, owner)) {
 142                     performed.add(pos, owner);
 143                     if (owner.hated != null)
 144                         for(Sequence seq : owner.hated)
 145                             if (performed.contains(pos, seq)) {
 146                                 performed.remove(pos, seq);
 147                                 reset = true;
 148                             }
 149                 }
 150             }
 151             newNode(parent, pending, state, fromEmptyReduction);
 152             if (reduction != null) {
 153                 boolean redo = true;
 154                 while(redo) {
 155                     redo = false;
 156                     for(Waiting w : waiting.getAll(owner)) {
 157                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 158                             waiting.remove(owner, w);
 159                             w.perform();
 160                             redo = true;
 161                             break;
 162                         }
 163                     }
 164                 }
 165             }
 166         }
 167
 168         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 169             if (p.merge(parent, pending)) return true;
 170             p.parents().add(parent, true);
 171             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 172             return true;
 173         }
 174
 175         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 176             do {
 177                 if (token != null && state.canShift(token)) break;
 178                 if (state.isAccepting()) break;
 179                 if (token==null) break;
 180                 if (!state.canReduce(token)) return false;
 181                 //if (count > 1) break;
 182                 //if (r.numPop == 0) break;
 183                 //r.reduce(pending, parent, null, Phase.this, null);
 184                 //return;
 185             } while(false);
 186
 187             Node n = new Node(parent, pending, state);  // ALLOC
 188             if (reducing) {
 189                 n.performEmptyReductions();
 190                 if (!fromEmptyReduction) n.performReductions(parent);
 191             }
 192             return true;
 193         }
 194
 195         /** perform all reduction operations */
 196         public void reduce() throws ParseFailed {
 197             try {
 198                 reducing = true;
 199                 if (reducing_list==null || reducing_list.length < hash.size())
 200                     reducing_list = new Phase.Node[hash.size() * 4];
 201                 hash.toArray(reducing_list);
 202                 int num = hash.size();
 203                 for(int i=0; i<num; i++) {
 204                     Node n = reducing_list[i];
 205                     n.performEmptyReductions();
 206                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 207                 }
 208                 for(int i=0; i<num; i++) {
 209                     Node n = reducing_list[i];
 210                     reducing_list[i] = null;
 211                     n.performReductions();
 212                 }
 213                 if (reset) {
 214                     reset = false;
 215                     resets++;
 216                     throw new Reset();
 217                 }
 218                 for(int i : expected)
 219                     for(Sequence s : expected.getAll(i))
 220                         if (!performed.contains(i, s)) {
 221                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 222                             resets++;
 223                             throw new Reset();
 224                         }
 225             } catch (Reset r) {
 226                 reset();
 227                 reduce();
 228             }
 229             count = 0;
 230         }
 231
 232         private boolean reset = false;
 233         class Reset extends RuntimeException { }
 234
 235         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 236         public void shift(Phase next, Forest result) throws ParseFailed {
 237             // this massively improves GC performance
 238             if (prev!=null && parser.helpgc) {
 239                 prev.hash = null;
 240             }
 241             this.next = next;
 242             closed = true;
 243             Forest res = null;
 244             boolean ok = false;
 245             for(Phase.Node n : hash.values()) {
 246                 if (token == null && n.state.isAccepting()) {
 247                     if (finalResult==null) finalResult = new Forest.Many();
 248                     for(Object f : n.results())
 249                         finalResult.merge((Forest)f);
 250                 }
 251                 if (token == null) continue;
 252                 n.state.invokeShifts(token, this, result, n);
 253             }
 254
 255             if (!good && token!=null)
 256                 throw new ParseFailed(ParseFailed.error(("unexpected character ")+" \'"+
 257                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 258                                                         "\' encountered at "+
 259                                                         ANSI.green(next.getRegion())+"\n", token, hash.values()),
 260                                         next.getRegion(), input);
 261             if (token==null && finalResult==null)
 262                 throw new ParseFailed(ParseFailed.error(("unexpected end of file at "+getLocation()+"\n"), token, hash.values()),
 263                                       getLocation().createRegion(getLocation()), input);
 264         }
 265
 266
 267         class Waiting {
 268             Node parent;
 269             Forest pending;
 270             State state;
 271             boolean fromEmptyReduction;
 272             Position reduction;
 273             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 274                 waits++;
 275                 this.parent = parent;
 276                 this.pending = pending;
 277                 this.state = state;
 278                 this.fromEmptyReduction = fromEmptyReduction;
 279                 this.reduction = reduction;
 280             }
 281             public void perform() {
 282                 //System.out.println("performing: " + reduction.position);
 283                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 284             }
 285         }
 286
 287         // Node /////////////////////////////////////////////////////////////////////////////////
 288
 289         /** a node in the GSS */
 290         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 291             public FastSet<Node> set = new FastSet<Node>();
 292
 293
 294             private boolean allqueued = false;
 295
 296             /** what state this node is in */
 297             public final Parser.Table<Tok>.State<Tok> state;
 298
 299             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 300             public  Phase phase() { return Phase.this; }
 301
 302             private HashSet<Forest.Many> resultMap = new HashSet<Forest.Many>();
 303             public Iterable<Forest.Many> results() { return resultMap; }
 304             public FastSet<Node> parents() { return set; }
 305             public boolean merge(Node parent, Forest result) {
 306                 // FIXME: inefficient!
 307                 for(Forest.Many f : results()) {
 308                     if (f.parents.contains(parent) /* UGLY: */ && f.parents.size()==1) {
 309                         f.merge(result);
 310                         return true;
 311                     }
 312                 }
 313                 Forest.Many f = new Forest.Many();
 314                 f.parents.add(parent);
 315                 f.merge(result);
 316                 resultMap.add(f);
 317                 set.add(parent, true);
 318                 return false;
 319             }
 320
 321             public void performReductions() {
 322                 if (allqueued) return;
 323                 allqueued = true;
 324                 state.invokeReductions(token, this, this, null);
 325             }
 326
 327             public void performReductions(Node n2) {
 328                 if (!allqueued) performReductions();
 329                 else            state.invokeReductions(token, this, this, n2);
 330             }
 331
 332             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 333             public final void invoke(Position r, Node n, Node n2) {
 334                 reductions++;
 335                 if (n==null || n2==null || r.pos==0) {
 336                     if (r.pos==0) {
 337                         if (n==null) n = this;
 338                         else return;
 339                     }
 340                     if (n==null) return;
 341                     Forest[] holder = new Forest[r.pos];
 342                     if (r.pos==0) n.finish(r, r.zero(n.phase().getLocation().createRegion(n.phase().getLocation())), n.phase());
 343                     else          n.reduce(r, r.pos-1,  n.phase(), null);
 344                 } else {
 345                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 346                     int pos = r.pos-1;
 347                     n.reduce(r, pos, n.phase(), n2);
 348                 }
 349             }
 350
 351             public void reduce(Position r, int pos, Phase target, Node only) {
 352                 Forest[] holder = r.holder;
 353                 Forest old = holder[pos];
 354
 355                 HashSet<Forest> rr = new HashSet<Forest>();
 356                 for(Forest result : results()) rr.add(result);
 357                 for(Forest result : rr)
 358                     for(Node child : ((Forest.Many<?>)result).parents) {
 359                         if (only != null && child!=only) continue;
 360                         holder[pos] = result;
 361                         if (pos==0) child.finish(r, r.rewrite(child.phase().getLocation().createRegion(target.getLocation())), target);
 362                         else        child.reduce(r, pos-1, target, null);
 363                     }
 364
 365                 holder[pos] = old;
 366             }
 367
 368             public void finish(Position r, Forest result, Phase<Tok> target) {
 369                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 370                 if (result==null) throw new Error();
 371                 if (state0!=null)
 372                     target.newNode(this, result, state0, r.pos<=0, r);
 373             }
 374
 375             private Node(Node parent, Forest pending, State state) {
 376                 this.state = state;
 377                 this.merge(parent, pending);
 378                 Phase start = parent==null ? null : parent.phase();
 379                 if (parent != null) parents().add(parent, true);
 380                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 381                 Phase.this.hash.put(state, start, this);
 382             }
 383             public int toInt() { return idx; }
 384             private final int idx = node_idx++;
 385
 386             // GraphViz //////////////////////////////////////////////////////////////////////////////
 387
 388             public GraphViz.Node toGraphViz(GraphViz gv) {
 389                 if (gv.hasNode(this)) return gv.createNode(this);
 390                 GraphViz.Node n = gv.createNode(this);
 391                 n.label = ""+state.toStringx();
 392                 n.shape = "rectangle";
 393                 n.fill = "green";
 394                 for(Forest result : results()) n.edge(result, "");
 395                 for(Node parent : parents()) n.edge(parent, "");
 396                 ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 397                 return n;
 398             }
 399             public boolean isTransparent() { return false; }
 400             public boolean isHidden() { return false; }
 401
 402         }
 403         private int node_idx = 0;
 404
 405         public int toInt() { return pos+1; }
 406         public int size() { return hash==null ? 0 : hash.size(); }
 407
 408         // GraphViz //////////////////////////////////////////////////////////////////////////////
 409
 410         public GraphViz.Node toGraphViz(GraphViz gv) {
 411             if (gv.hasNode(this)) return gv.createNode(this);
 412             GraphViz.Group g = gv.createGroup(this);
 413             g.label = "Phase " + pos;
 414             g.color = "gray";
 415             g.cluster = true;
 416             return g;
 417         }
 418         public boolean isTransparent() { return false; }
 419         public boolean isHidden() { return false; }
 420
 421     }
 422 }