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