src/edu/berkeley/sbp/GSS.java

   1 package edu.berkeley.sbp;
   2 import edu.berkeley.sbp.*;
   3 import edu.berkeley.sbp.util.*;
   4 import edu.berkeley.sbp.Parser.Table.*;
   5 import edu.berkeley.sbp.Sequence.Position;
   6 import java.io.*;
   7 import java.util.*;
   8 import java.lang.reflect.*;
   9
  10 /** implements Tomita's Graph Structured Stack */
  11 public class GSS {
  12
  13     public static int count = 0;
  14     public static int shifts = 0;
  15     public static int reductions = 0;
  16
  17     public GSS() { }
  18
  19     private Phase.Node[] reducing_list = null;
  20     public int resets = 0;
  21     public int waits = 0;
  22
  23     // FIXME: right now, these are the performance bottleneck
  24     HashMapBag<Sequence,Phase.Waiting> waiting         = new HashMapBag<Sequence,Phase.Waiting>();
  25     HashMapBag<Integer,Sequence>       performed       = new HashMapBag<Integer,Sequence>();
  26     HashMapBag<Integer,Sequence>       lastperformed   = new HashMapBag<Integer,Sequence>();
  27     HashMapBag<Integer,Sequence>       expected        = new HashMapBag<Integer,Sequence>();
  28
  29     /** FIXME */
  30     public  Forest.Ref finalResult;
  31
  32     /** corresponds to a positions <i>between tokens</i> the input stream; same as Tomita's U_i's */
  33     class Phase<Tok> implements Invokable<State, Forest, Phase<Tok>.Node>, IntegerMappable, GraphViz.ToGraphViz, Iterable<Phase.Node> {
  34
  35         public Iterator<Phase.Node> iterator() { return hash.iterator(); }
  36         public void invoke(State st, Forest result, Node n) {
  37             shifts++;
  38             good |= next.newNode(n, result, st, false);
  39         }
  40
  41         /** the token immediately after this phase */
  42         final Tok token;
  43
  44         private final int pos;
  45
  46         boolean reducing;
  47         private IntPairMap<Phase.Node> hash;  /* ALLOC */
  48         private boolean closed;
  49         private boolean good;
  50         private Phase next = null;
  51         private Phase prev;
  52         private Input.Location location;
  53         public final Parser parser;
  54
  55         private Forest forest;
  56
  57         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Forest forest) throws ParseFailed {
  58             this.prev = prev;
  59             this.forest = forest;
  60             this.parser = parser;
  61             this.pos = previous==null ? 0 : previous.pos+1;
  62             this.token = token;
  63             this.location = location;
  64             performed.clear();
  65             reset();
  66         }
  67
  68         public void reset() throws ParseFailed {
  69             waiting.clear();
  70             expected.clear();
  71             lastperformed.clear();
  72             lastperformed.addAll(performed);
  73             performed.clear();
  74             hash = new IntPairMap<Phase.Node>();
  75             reset = false;
  76             good = false;
  77             closed = false;
  78             reducing = false;
  79             finalResult = null;
  80             if (prev != null) prev.shift(this, forest);
  81         }
  82
  83
  84         public boolean isDone() throws ParseFailed {
  85             if (token != null) return false;
  86             if (token==null && finalResult==null)
  87                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  88             return true;
  89         }
  90
  91         public Input.Location getLocation() { return location; }
  92
  93         /** add a new node (merging with existing nodes if possible)
  94          *  @param parent             the parent of the new node
  95          *  @param result             the SPPF result corresponding to the new node
  96          *  @param state              the state that the new node is in
  97          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
  98          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
  99          */
 100         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 101             Node p = hash.get(state, parent==null?null:parent.phase());
 102             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 103             else            return newNode3(parent, pending, state, fromEmptyReduction);
 104         }
 105         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 106             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 107             Sequence owner = reduction==null ? null : reduction.owner();
 108             if (reduction!=null) {
 109                 if (owner.hates!=null) {
 110                     for (Sequence s : performed.getAll(pos))
 111                         if (owner.hates.contains(s))
 112                             return;
 113                     for (Sequence s : lastperformed.getAll(pos))
 114                         if (owner.hates.contains(s)) {
 115                             //System.out.println("now expecting ["+pos+"] => " + s);
 116                             expected.add(pos, s);
 117                             return;
 118                         }
 119                 }
 120                 if (owner.needs != null)
 121                     for(Sequence s : owner.needs)
 122                         if (!performed.contains(pos, s)) {
 123                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 124                             return;
 125                         }
 126                 if (!performed.contains(pos, owner)) {
 127                     performed.add(pos, owner);
 128                     if (owner.hated != null)
 129                         for(Sequence seq : owner.hated)
 130                             if (performed.contains(pos, seq)) {
 131                                 performed.remove(pos, seq);
 132                                 reset = true;
 133                             }
 134                 }
 135             }
 136             if (!owner.lame)
 137                 newNode(parent, pending, state, fromEmptyReduction);
 138             if (reduction != null) {
 139                 boolean redo = true;
 140                 while(redo) {
 141                     redo = false;
 142                     for(Waiting w : waiting.getAll(owner)) {
 143                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 144                             waiting.remove(owner, w);
 145                             w.perform();
 146                             redo = true;
 147                             break;
 148                         }
 149                     }
 150                 }
 151             }
 152         }
 153
 154         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 155             if (p.merge(parent, pending)) return true;
 156             p.parents().add(parent, true);
 157             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 158             return true;
 159         }
 160
 161         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 162             do {
 163                 if (token != null && state.canShift(token)) break;
 164                 if (state.isAccepting()) break;
 165                 if (token==null) break;
 166                 if (!state.canReduce(token)) return false;
 167                 //if (count > 1) break;
 168                 //if (r.numPop == 0) break;
 169                 //r.reduce(pending, parent, null, Phase.this, null);
 170                 //return;
 171             } while(false);
 172
 173             Node n = new Node(parent, pending, state);  // ALLOC
 174             if (reducing) {
 175                 n.performEmptyReductions();
 176                 if (!fromEmptyReduction) n.performReductions(parent);
 177             }
 178             return true;
 179         }
 180
 181         /** perform all reduction operations */
 182         public void reduce() throws ParseFailed {
 183             try {
 184                 reducing = true;
 185                 if (reducing_list==null || reducing_list.length < hash.size())
 186                     reducing_list = new Phase.Node[hash.size() * 4];
 187                 hash.toArray(reducing_list);
 188                 int num = hash.size();
 189                 for(int i=0; i<num; i++) {
 190                     Node n = reducing_list[i];
 191                     n.performEmptyReductions();
 192                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 193                 }
 194                 for(int i=0; i<num; i++) {
 195                     Node n = reducing_list[i];
 196                     reducing_list[i] = null;
 197                     n.performReductions();
 198                 }
 199                 if (reset) {
 200                     reset = false;
 201                     resets++;
 202                     throw new Reset();
 203                 }
 204                 for(int i : expected)
 205                     for(Sequence s : expected.getAll(i))
 206                         if (!performed.contains(i, s)) {
 207                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 208                             resets++;
 209                             throw new Reset();
 210                         }
 211             } catch (Reset r) {
 212                 reset();
 213                 reduce();
 214             }
 215             count = 0;
 216         }
 217
 218         private boolean reset = false;
 219         class Reset extends RuntimeException { }
 220
 221         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 222         public void shift(Phase next, Forest result) throws ParseFailed {
 223             // this massively improves GC performance
 224             if (prev!=null && parser.helpgc) {
 225                 prev.hash = null;
 226             }
 227             this.next = next;
 228             closed = true;
 229             Forest res = null;
 230             boolean ok = false;
 231             for(Phase.Node n : hash.values()) {
 232                 if (token == null && n.state.isAccepting()) {
 233                     if (finalResult==null) finalResult = new Forest.Ref();
 234                     for(Object f : n.results())
 235                         finalResult.merge((Forest)f);
 236                 }
 237                 if (token == null) continue;
 238                 n.state.invokeShifts(token, this, result, n);
 239             }
 240
 241             if (!good && token!=null)
 242                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 243                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 244                                                         "\' encountered at "+
 245                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 246                                         getLocation());
 247             if (token==null && finalResult==null)
 248                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 249                                         getLocation());
 250         }
 251
 252
 253         class Waiting {
 254             Node parent;
 255             Forest pending;
 256             State state;
 257             boolean fromEmptyReduction;
 258             Position reduction;
 259             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 260                 waits++;
 261                 this.parent = parent;
 262                 this.pending = pending;
 263                 this.state = state;
 264                 this.fromEmptyReduction = fromEmptyReduction;
 265                 this.reduction = reduction;
 266             }
 267             public void perform() {
 268                 //System.out.println("performing: " + reduction.position);
 269                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 270             }
 271         }
 272
 273         // Node /////////////////////////////////////////////////////////////////////////////////
 274
 275         /** a node in the GSS */
 276         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 277             public FastSet<Node> set = new FastSet<Node>();
 278
 279
 280             private boolean allqueued = false;
 281
 282             /** what state this node is in */
 283             public final Parser.Table<Tok>.State<Tok> state;
 284
 285             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 286             public  Phase phase() { return Phase.this; }
 287
 288             private HashSet<Forest.Ref> resultMap = new HashSet<Forest.Ref>();
 289             public Iterable<Forest.Ref> results() { return resultMap; }
 290             public FastSet<Node> parents() { return set; }
 291             public boolean merge(Node parent, Forest result) {
 292                 // FIXME: inefficient!
 293                 for(Forest.Ref f : results()) {
 294                     if (f.parents.contains(parent) /* UGLY: */ && f.parents.size()==1) {
 295                         f.merge(result);
 296                         return true;
 297                     }
 298                 }
 299                 Forest.Ref f = new Forest.Ref();
 300                 f.parents.add(parent);
 301                 f.merge(result);
 302                 resultMap.add(f);
 303                 set.add(parent, true);
 304                 return false;
 305             }
 306
 307             public void performReductions() {
 308                 if (allqueued) return;
 309                 allqueued = true;
 310                 state.invokeReductions(token, this, this, null);
 311             }
 312
 313             public void performReductions(Node n2) {
 314                 if (!allqueued) performReductions();
 315                 else            state.invokeReductions(token, this, this, n2);
 316             }
 317
 318             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 319             public final void invoke(Position r, Node n, Node n2) {
 320                 reductions++;
 321                 if (n==null || n2==null || r.pos==0) {
 322                     if (r.pos==0) {
 323                         if (n==null) n = this;
 324                         else return;
 325                     }
 326                     if (n==null) return;
 327                     Forest[] holder = new Forest[r.pos];
 328                     if (r.pos==0) n.finish(r, r.zero(), n.phase());
 329                     else          n.reduce(r, r.pos-1,  n.phase(), null);
 330                 } else {
 331                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 332                     int pos = r.pos-1;
 333                     n.reduce(r, pos, n.phase(), n2);
 334                 }
 335             }
 336
 337             public void reduce(Position r, int pos, Phase target, Node only) {
 338                 Forest[] holder = r.holder;
 339                 Forest old = holder[pos];
 340
 341                 for(Forest result : results())
 342                     for(Node child : ((Forest.Ref<?>)result).parents) {
 343                         if (only != null && child!=only) continue;
 344                         holder[pos] = result;
 345                         if (pos==0) child.finish(r, r.rewrite(phase().getLocation()), target);
 346                         else        child.reduce(r, pos-1, target, null);
 347                     }
 348
 349                 holder[pos] = old;
 350             }
 351
 352             public void finish(Position r, Forest result, Phase<Tok> target) {
 353                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 354                 if (result==null) throw new Error();
 355                 if (state0!=null)
 356                     target.newNode(this, result, state0, r.pos<=0, r);
 357             }
 358
 359             private Node(Node parent, Forest pending, State state) {
 360                 this.state = state;
 361                 this.merge(parent, pending);
 362                 Phase start = parent==null ? null : parent.phase();
 363                 if (parent != null) parents().add(parent, true);
 364                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 365                 Phase.this.hash.put(state, start, this);
 366             }
 367             public int toInt() { return idx; }
 368             private final int idx = node_idx++;
 369
 370             // GraphViz //////////////////////////////////////////////////////////////////////////////
 371
 372             public GraphViz.Node toGraphViz(GraphViz gv) {
 373                 if (gv.hasNode(this)) return gv.createNode(this);
 374                 GraphViz.Node n = gv.createNode(this);
 375                 n.label = ""+state.toStringx();
 376                 n.shape = "rectangle";
 377                 n.fill = "green";
 378                 for(Forest result : results()) n.edge(result, "");
 379                 for(Node parent : parents()) n.edge(parent, "");
 380                 ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 381                 return n;
 382             }
 383             public boolean isTransparent() { return false; }
 384             public boolean isHidden() { return false; }
 385
 386         }
 387         private int node_idx = 0;
 388
 389         public int toInt() { return pos+1; }
 390         public int size() { return hash==null ? 0 : hash.size(); }
 391
 392         // GraphViz //////////////////////////////////////////////////////////////////////////////
 393
 394         public GraphViz.Node toGraphViz(GraphViz gv) {
 395             if (gv.hasNode(this)) return gv.createNode(this);
 396             GraphViz.Group g = gv.createGroup(this);
 397             g.label = "Phase " + pos;
 398             g.color = "gray";
 399             g.cluster = true;
 400             return g;
 401         }
 402         public boolean isTransparent() { return false; }
 403         public boolean isHidden() { return false; }
 404
 405     }
 406 }