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8154751: MethodHandles.countedLoop does not accept empty bodies

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Reviewed-by: redestad
This commit is contained in:
Michael Haupt 2016-04-22 15:05:26 +02:00
parent 5b392c0abc
commit e53e280d37
2 changed files with 26 additions and 4 deletions
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12
jdk/src/java.base/share/classes/java/lang/invoke/MethodHandles.java
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@ -4476,12 +4476,16 @@ assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum"));
* @since 9
*/
public static MethodHandle countedLoop(MethodHandle start, MethodHandle end, MethodHandle init, MethodHandle body) {
MethodHandle returnVar = dropArguments(init == null || init.type().returnType() == void.class ?
zero(void.class) : identity(init.type().returnType()), 0, int.class, int.class);
MethodHandle defaultResultHandle = init == null || init.type().returnType() == void.class ?
zero(void.class) :
identity(init.type().returnType());
MethodHandle adaptedBody = body == null ? dropArguments(defaultResultHandle, 0, int.class) : body;
MethodHandle returnVar = dropArguments(defaultResultHandle, 0, int.class, int.class);
MethodHandle[] indexVar = {start, MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopStep)};
MethodHandle[] loopLimit = {end, null, MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopPred), returnVar};
MethodHandle[] loopLimit = {end, null, MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopPred),
returnVar};
MethodHandle[] bodyClause = {init,
filterArgument(dropArguments(body, 1, int.class), 0,
filterArgument(dropArguments(adaptedBody, 1, int.class), 0,
MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_decrementCounter))};
return loop(indexVar, loopLimit, bodyClause);
}

18
jdk/test/java/lang/invoke/LoopCombinatorTest.java
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@ -30,6 +30,7 @@
* @bug 8150957
* @bug 8152667
* @bug 8153637
* @bug 8154751
* @run testng/othervm -ea -esa test.java.lang.invoke.LoopCombinatorTest
*/
@ -347,6 +348,23 @@ public class LoopCombinatorTest {
assertEquals(10, loop.invoke());
}
@Test
public static void testCountedLoopEmpty() throws Throwable {
// for (int i = 0; i < 5; ++i) { /* empty */ }
MethodHandle loop = MethodHandles.countedLoop(MethodHandles.constant(int.class, 5), null, null);
assertEquals(methodType(void.class), loop.type());
loop.invoke();
}
@Test
public static void testCountedRangeLoopEmpty() throws Throwable {
// for (int i = -5; i < 5; ++i) { /* empty */ }
MethodHandle loop = MethodHandles.countedLoop(MethodHandles.constant(int.class, -5),
MethodHandles.constant(int.class, 5), null, null);
assertEquals(methodType(void.class), loop.type());
loop.invoke();
}
@Test
public static void testIterateSum() throws Throwable {
// Integer[] a = new Integer[]{1,2,3,4,5,6}; int sum = 0; for (int e : a) { sum += e; } return sum; => 21