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 class GSS {
  12
  13     static int count = 0;
  14     static int shifts = 0;
  15     static int reductions = 0;
  16     int resets = 0;
  17     int waits = 0;
  18
  19     public GSS() { }
  20
  21     private Phase.Node[] reducing_list = null;
  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     Forest.Many 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         private Input.Location nextLocation;
  54         public final Parser parser;
  55
  56         private Forest forest;
  57
  58         public Phase(Phase prev, Parser parser, Phase previous, Tok token, Input.Location location, Input.Location nextLocation, Forest forest) throws ParseFailed {
  59             this.prev = prev;
  60             this.forest = forest;
  61             this.parser = parser;
  62             this.pos = previous==null ? 0 : previous.pos+1;
  63             this.token = token;
  64             this.location = location;
  65             this.nextLocation = nextLocation;
  66             performed.clear();
  67             reset();
  68         }
  69
  70         public void reset() throws ParseFailed {
  71             waiting.clear();
  72             expected.clear();
  73             lastperformed.clear();
  74             lastperformed.addAll(performed);
  75             performed.clear();
  76             hash = new IntPairMap<Phase.Node>();
  77             reset = false;
  78             good = false;
  79             closed = false;
  80             reducing = false;
  81             finalResult = null;
  82             if (prev != null) prev.shift(this, forest);
  83         }
  84
  85
  86         public boolean isDone() throws ParseFailed {
  87             if (token != null) return false;
  88             if (token==null && finalResult==null)
  89                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()), getLocation());
  90             return true;
  91         }
  92
  93         public Input.Location getLocation() { return location; }
  94         public Input.Location getNextLocation() { return nextLocation; }
  95
  96         /** add a new node (merging with existing nodes if possible)
  97          *  @param parent             the parent of the new node
  98          *  @param result             the SPPF result corresponding to the new node
  99          *  @param state              the state that the new node is in
 100          *  @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
 101          *  @param start              the earliest part of the input contributing to this node (used to make merging decisions)
 102          */
 103         public boolean newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 104             Node p = hash.get(state, parent==null?null:parent.phase());
 105             if (p != null)  return newNode2(p, parent, pending, state, fromEmptyReduction);
 106             else            return newNode3(parent, pending, state, fromEmptyReduction);
 107         }
 108         public void newNode(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 109             int pos = parent==null?0:parent.phase()==null?0:parent.phase().pos;
 110             Sequence owner = reduction==null ? null : reduction.owner();
 111             if (reduction!=null) {
 112                 if (owner.hates!=null) {
 113                     for (Sequence s : performed.getAll(pos))
 114                         if (owner.hates.contains(s))
 115                             return;
 116                     for (Sequence s : lastperformed.getAll(pos))
 117                         if (owner.hates.contains(s)) {
 118                             //System.out.println("now expecting ["+pos+"] => " + s);
 119                             expected.add(pos, s);
 120                             return;
 121                         }
 122                 }
 123                 if (owner.needs != null)
 124                     for(Sequence s : owner.needs)
 125                         if (!performed.contains(pos, s)) {
 126                             waiting.add(s, new Waiting(parent, pending, state, fromEmptyReduction, reduction));
 127                             return;
 128                         }
 129                 if (!performed.contains(pos, owner)) {
 130                     performed.add(pos, owner);
 131                     if (owner.hated != null)
 132                         for(Sequence seq : owner.hated)
 133                             if (performed.contains(pos, seq)) {
 134                                 performed.remove(pos, seq);
 135                                 reset = true;
 136                             }
 137                 }
 138             }
 139             newNode(parent, pending, state, fromEmptyReduction);
 140             if (reduction != null) {
 141                 boolean redo = true;
 142                 while(redo) {
 143                     redo = false;
 144                     for(Waiting w : waiting.getAll(owner)) {
 145                         if (w.parent==parent || (parent!=null&&w.parent!=null&&w.parent.phase()==parent.phase())) {
 146                             waiting.remove(owner, w);
 147                             w.perform();
 148                             redo = true;
 149                             break;
 150                         }
 151                     }
 152                 }
 153             }
 154         }
 155
 156         private boolean newNode2(Node p, Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 157             if (p.merge(parent, pending)) return true;
 158             p.parents().add(parent, true);
 159             if (p!=parent && !fromEmptyReduction && reducing) p.performReductions(parent);
 160             return true;
 161         }
 162
 163         private boolean newNode3(Node parent, Forest pending, State state, boolean fromEmptyReduction) {
 164             do {
 165                 if (token != null && state.canShift(token)) break;
 166                 if (state.isAccepting()) break;
 167                 if (token==null) break;
 168                 if (!state.canReduce(token)) return false;
 169                 //if (count > 1) break;
 170                 //if (r.numPop == 0) break;
 171                 //r.reduce(pending, parent, null, Phase.this, null);
 172                 //return;
 173             } while(false);
 174
 175             Node n = new Node(parent, pending, state);  // ALLOC
 176             if (reducing) {
 177                 n.performEmptyReductions();
 178                 if (!fromEmptyReduction) n.performReductions(parent);
 179             }
 180             return true;
 181         }
 182
 183         /** perform all reduction operations */
 184         public void reduce() throws ParseFailed {
 185             try {
 186                 reducing = true;
 187                 if (reducing_list==null || reducing_list.length < hash.size())
 188                     reducing_list = new Phase.Node[hash.size() * 4];
 189                 hash.toArray(reducing_list);
 190                 int num = hash.size();
 191                 for(int i=0; i<num; i++) {
 192                     Node n = reducing_list[i];
 193                     n.performEmptyReductions();
 194                     // INVARIANT: we never "see" a node until its parent-set is complete, modulo merges
 195                 }
 196                 for(int i=0; i<num; i++) {
 197                     Node n = reducing_list[i];
 198                     reducing_list[i] = null;
 199                     n.performReductions();
 200                 }
 201                 if (reset) {
 202                     reset = false;
 203                     resets++;
 204                     throw new Reset();
 205                 }
 206                 for(int i : expected)
 207                     for(Sequence s : expected.getAll(i))
 208                         if (!performed.contains(i, s)) {
 209                             //System.out.println("resetting due to pos="+i+": " + s + " " + System.identityHashCode(s));
 210                             resets++;
 211                             throw new Reset();
 212                         }
 213             } catch (Reset r) {
 214                 reset();
 215                 reduce();
 216             }
 217             count = 0;
 218         }
 219
 220         private boolean reset = false;
 221         class Reset extends RuntimeException { }
 222
 223         /** perform all shift operations, adding promoted nodes to <tt>next</tt> */
 224         public void shift(Phase next, Forest result) throws ParseFailed {
 225             // this massively improves GC performance
 226             if (prev!=null && parser.helpgc) {
 227                 prev.hash = null;
 228             }
 229             this.next = next;
 230             closed = true;
 231             Forest res = null;
 232             boolean ok = false;
 233             for(Phase.Node n : hash.values()) {
 234                 if (token == null && n.state.isAccepting()) {
 235                     if (finalResult==null) finalResult = new Forest.Many();
 236                     for(Object f : n.results())
 237                         finalResult.merge((Forest)f);
 238                 }
 239                 if (token == null) continue;
 240                 n.state.invokeShifts(token, this, result, n);
 241             }
 242
 243             if (!good && token!=null)
 244                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected character ")+" \'"+
 245                                                         ANSI.purple(StringUtil.escapify(token+"", "\\\'\r\n"))+
 246                                                         "\' encountered at "+
 247                                                         ANSI.green(getLocation())+"\n", token, hash.values()),
 248                                         getLocation());
 249             if (token==null && finalResult==null)
 250                 throw new ParseFailed(ParseFailed.error(ANSI.red("unexpected end of file\n"), token, hash.values()),
 251                                         getLocation());
 252         }
 253
 254
 255         class Waiting {
 256             Node parent;
 257             Forest pending;
 258             State state;
 259             boolean fromEmptyReduction;
 260             Position reduction;
 261             public Waiting(Node parent, Forest pending, State state, boolean fromEmptyReduction, Position reduction) {
 262                 waits++;
 263                 this.parent = parent;
 264                 this.pending = pending;
 265                 this.state = state;
 266                 this.fromEmptyReduction = fromEmptyReduction;
 267                 this.reduction = reduction;
 268             }
 269             public void perform() {
 270                 //System.out.println("performing: " + reduction.position);
 271                 newNode(parent, pending, state, fromEmptyReduction, reduction);
 272             }
 273         }
 274
 275         // Node /////////////////////////////////////////////////////////////////////////////////
 276
 277         /** a node in the GSS */
 278         final class Node implements Invokable<Position, Node, Node>, IntegerMappable, GraphViz.ToGraphViz {
 279             public FastSet<Node> set = new FastSet<Node>();
 280
 281
 282             private boolean allqueued = false;
 283
 284             /** what state this node is in */
 285             public final Parser.Table<Tok>.State<Tok> state;
 286
 287             /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
 288             public  Phase phase() { return Phase.this; }
 289
 290             private HashSet<Forest.Many> resultMap = new HashSet<Forest.Many>();
 291             public Iterable<Forest.Many> results() { return resultMap; }
 292             public FastSet<Node> parents() { return set; }
 293             public boolean merge(Node parent, Forest result) {
 294                 // FIXME: inefficient!
 295                 for(Forest.Many f : results()) {
 296                     if (f.parents.contains(parent) /* UGLY: */ && f.parents.size()==1) {
 297                         f.merge(result);
 298                         return true;
 299                     }
 300                 }
 301                 Forest.Many f = new Forest.Many();
 302                 f.parents.add(parent);
 303                 f.merge(result);
 304                 resultMap.add(f);
 305                 set.add(parent, true);
 306                 return false;
 307             }
 308
 309             public void performReductions() {
 310                 if (allqueued) return;
 311                 allqueued = true;
 312                 state.invokeReductions(token, this, this, null);
 313             }
 314
 315             public void performReductions(Node n2) {
 316                 if (!allqueued) performReductions();
 317                 else            state.invokeReductions(token, this, this, n2);
 318             }
 319
 320             public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
 321             public final void invoke(Position r, Node n, Node n2) {
 322                 reductions++;
 323                 if (n==null || n2==null || r.pos==0) {
 324                     if (r.pos==0) {
 325                         if (n==null) n = this;
 326                         else return;
 327                     }
 328                     if (n==null) return;
 329                     Forest[] holder = new Forest[r.pos];
 330                     if (r.pos==0) n.finish(r, r.zero(n.phase().getLocation().createRegion(n.phase().getLocation())), n.phase());
 331                     else          n.reduce(r, r.pos-1,  n.phase(), null);
 332                 } else {
 333                     if (r.pos<=0) throw new Error("called wrong form of reduce()");
 334                     int pos = r.pos-1;
 335                     n.reduce(r, pos, n.phase(), n2);
 336                 }
 337             }
 338
 339             public void reduce(Position r, int pos, Phase target, Node only) {
 340                 Forest[] holder = r.holder;
 341                 Forest old = holder[pos];
 342
 343                 HashSet<Forest> rr = new HashSet<Forest>();
 344                 for(Forest result : results()) rr.add(result);
 345                 for(Forest result : rr)
 346                     for(Node child : ((Forest.Many<?>)result).parents) {
 347                         if (only != null && child!=only) continue;
 348                         holder[pos] = result;
 349                         if (pos==0) child.finish(r, r.rewrite(child.phase().getNextLocation().createRegion(target.getLocation())), target);
 350                         else        child.reduce(r, pos-1, target, null);
 351                     }
 352
 353                 holder[pos] = old;
 354             }
 355
 356             public void finish(Position r, Forest result, Phase<Tok> target) {
 357                 Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
 358                 if (result==null) throw new Error();
 359                 if (state0!=null)
 360                     target.newNode(this, result, state0, r.pos<=0, r);
 361             }
 362
 363             private Node(Node parent, Forest pending, State state) {
 364                 this.state = state;
 365                 this.merge(parent, pending);
 366                 Phase start = parent==null ? null : parent.phase();
 367                 if (parent != null) parents().add(parent, true);
 368                 if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
 369                 Phase.this.hash.put(state, start, this);
 370             }
 371             public int toInt() { return idx; }
 372             private final int idx = node_idx++;
 373
 374             // GraphViz //////////////////////////////////////////////////////////////////////////////
 375
 376             public GraphViz.Node toGraphViz(GraphViz gv) {
 377                 if (gv.hasNode(this)) return gv.createNode(this);
 378                 GraphViz.Node n = gv.createNode(this);
 379                 n.label = ""+state.toStringx();
 380                 n.shape = "rectangle";
 381                 n.fill = "green";
 382                 for(Forest result : results()) n.edge(result, "");
 383                 for(Node parent : parents()) n.edge(parent, "");
 384                 ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
 385                 return n;
 386             }
 387             public boolean isTransparent() { return false; }
 388             public boolean isHidden() { return false; }
 389
 390         }
 391         private int node_idx = 0;
 392
 393         public int toInt() { return pos+1; }
 394         public int size() { return hash==null ? 0 : hash.size(); }
 395
 396         // GraphViz //////////////////////////////////////////////////////////////////////////////
 397
 398         public GraphViz.Node toGraphViz(GraphViz gv) {
 399             if (gv.hasNode(this)) return gv.createNode(this);
 400             GraphViz.Group g = gv.createGroup(this);
 401             g.label = "Phase " + pos;
 402             g.color = "gray";
 403             g.cluster = true;
 404             return g;
 405         }
 406         public boolean isTransparent() { return false; }
 407         public boolean isHidden() { return false; }
 408
 409     }
 410 }