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8043725: javac fails with StackOverflowException

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Loose type comparison test should be protected against infinite recursion with fbounds

Reviewed-by: vromero
This commit is contained in:
Maurizio Cimadamore 2014-06-09 12:54:02 +01:00
parent d71f75ae86
commit dab523a752
2 changed files with 69 additions and 5 deletions
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38
langtools/src/share/classes/com/sun/tools/javac/code/Types.java
View File

@ -1212,17 +1212,38 @@ public class Types {
TypeRelation isSameTypeLoose = new LooseSameTypeVisitor();
private class LooseSameTypeVisitor extends SameTypeVisitor {
/** cache of the type-variable pairs being (recursively) tested. */
private Set<TypePair> cache = new HashSet<>();
@Override
boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
return tv1.tsym == tv2.tsym && checkSameBounds(tv1, tv2);
}
@Override
protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
return containsTypeEquivalent(ts1, ts2);
}
}
/**
/**
* Since type-variable bounds can be recursive, we need to protect against
* infinite loops - where the same bounds are checked over and over recursively.
*/
private boolean checkSameBounds(TypeVar tv1, TypeVar tv2) {
TypePair p = new TypePair(tv1, tv2, true);
if (cache.add(p)) {
try {
return visit(tv1.getUpperBound(), tv2.getUpperBound());
} finally {
cache.remove(p);
}
} else {
return false;
}
}
};
/**
* Strict type-equality relation - type variables are considered
* equals if they share the same object identity.
*/
@ -3396,9 +3417,16 @@ public class Types {
class TypePair {
final Type t1;
final Type t2;
boolean strict;
TypePair(Type t1, Type t2) {
this(t1, t2, false);
}
TypePair(Type t1, Type t2, boolean strict) {
this.t1 = t1;
this.t2 = t2;
this.strict = strict;
}
@Override
public int hashCode() {
@ -3409,8 +3437,8 @@ public class Types {
if (!(obj instanceof TypePair))
return false;
TypePair typePair = (TypePair)obj;
return isSameType(t1, typePair.t1)
&& isSameType(t2, typePair.t2);
return isSameType(t1, typePair.t1, strict)
&& isSameType(t2, typePair.t2, strict);
}
}
Set<TypePair> mergeCache = new HashSet<>();

36
langtools/test/tools/javac/generics/inference/8043725/T8043725.java Normal file
View File

@ -0,0 +1,36 @@
/*
* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/**
* @test
* @bug 8043725
* @summary javac fails with StackOverflowException
* @compile T8043725.java
*/
class T8043725 {
<T extends Comparable<T>> T m(T v) {
//this will generate two upper bounds, T and Comparable<T'> respectively
//causing infinite recursion in lub (because of JLS 18.3.1).
return m(v);
}
}