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Fix bug in PredictionContext.arrayMerge

This commit is contained in:
Sam Harwell 2012-10-15 14:57:06 -05:00
parent c737baf20c
commit f9a63b8810
2 changed files with 28 additions and 16 deletions
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14
runtime/Java/src/org/antlr/v4/runtime/atn/PredictionContext.java
View File

@ -331,23 +331,15 @@ public abstract class PredictionContext implements Iterable<SingletonPredictionC
// trim merged if we combined a few that had same stack tops
if ( k < mergedParents.length ) { // write index < last position; trim
int lastSlot = mergedParents.length - 1;
int p = lastSlot; // walk backwards from last index until we find non-null parent
while ( p>=0 && mergedParents[p]==null ) { p--; }
// p is now last non-null index
assert p>=0; // could only happen to be <0 if two arrays with $
if ( p < lastSlot ) {
int n = p+1; // how many slots we really used in merge
if ( n == 1 ) { // for just one merged element, return singleton top
if ( k == 1 ) { // for just one merged element, return singleton top
PredictionContext a_ =
SingletonPredictionContext.create(mergedParents[0],
mergedInvokingStates[0]);
if ( mergeCache!=null ) mergeCache.put(a,b,a_);
return a_;
}
mergedParents = Arrays.copyOf(mergedParents, n);
mergedInvokingStates = Arrays.copyOf(mergedInvokingStates, n);
}
mergedParents = Arrays.copyOf(mergedParents, k);
mergedInvokingStates = Arrays.copyOf(mergedInvokingStates, k);
}
PredictionContext M =

20
tool/test/org/antlr/v4/test/TestGraphNodes.java
View File

@ -161,6 +161,26 @@ public class TestGraphNodes extends TestCase {
assertEquals(expecting, toDOTString(r, rootIsWildcard()));
}
@Test public void test_aa$_a$_$_fullCtx() {
PredictionContext empty = PredictionContext.EMPTY;
PredictionContext child1 = createSingleton(empty, 8);
PredictionContext right = PredictionContext.merge(empty, child1, false, null);
PredictionContext left = createSingleton(right, 8);
PredictionContext merged = PredictionContext.merge(left, right, false, null);
String actual = toDOTString(merged, false);
System.out.println(actual);
String expecting =
"digraph G {\n" +
"rankdir=LR;\n" +
" s0[shape=record, label=\"<p0>|<p1>$\"];\n" +
" s1[shape=record, label=\"<p0>|<p1>$\"];\n" +
" s2[label=\"$\"];\n" +
" s0:p0->s1[label=\"8\"];\n" +
" s1:p0->s2[label=\"8\"];\n" +
"}\n";
assertEquals(expecting, actual);
}
@Test public void test_ax$_a$_fullctx() {
PredictionContext x = x();
PredictionContext a1 = createSingleton(x, 1);