test/java/lang/invoke/LoopCombinatorTest.java

rev 14112 : 8153637: MethodHandles.countedLoop/3 initialises loop counter to 1 instead of 0

@@ -24,10 +24,12 @@
  */
 
 /* @test
  * @bug 8139885
  * @bug 8150635
+ * @bug 8150957
+ * @bug 8153637
  * @run testng/othervm -ea -esa test.java.lang.invoke.LoopCombinatorTest
  */
 
 package test.java.lang.invoke;
 

@@ -300,10 +302,22 @@
         assertEquals(Counted.MT_counted, loop.type());
         assertEquals("na na na na na na na na na na na na na Lambdaman!", loop.invoke("Lambdaman!"));
     }
 
     @Test
+    public static void testCountedLoopCounterInit() throws Throwable {
+        // int x = 0; for (int i = 0; i < 5; ++i) { x += i; } return x; => 10
+        // (only if counter's first value in body is 0)
+        MethodHandle iter = MethodHandles.constant(int.class, 5);
+        MethodHandle init = MethodHandles.constant(int.class, 0);
+        MethodHandle body = Counted.MH_addCounter;
+        MethodHandle loop = MethodHandles.countedLoop(iter, init, body);
+        assertEquals(Counted.MT_counterInit, loop.type());
+        assertEquals(10, 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
         MethodHandle loop = MethodHandles.iteratedLoop(Iterate.MH_sumIterator, Iterate.MH_sumInit, Iterate.MH_sumStep);
         assertEquals(Iterate.MT_sum, loop.type());
         assertEquals(21, loop.invoke(new Integer[]{1, 2, 3, 4, 5, 6}));

@@ -665,38 +679,46 @@
 
         static void printHello(int counter) {
             System.out.print("hello");
         }
 
+        static int addCounter(int counter, int x) {
+            return x + counter;
+        }
+
         static final Class<Counted> COUNTED = Counted.class;
 
         static final MethodType MT_start = methodType(String.class, String.class);
         static final MethodType MT_step = methodType(String.class, int.class, String.class, String.class);
         static final MethodType MT_stepUpdateArray = methodType(void.class, int.class, int[].class);
         static final MethodType MT_printHello = methodType(void.class, int.class);
+        static final MethodType MT_addCounter = methodType(int.class, int.class, int.class);
 
         static final MethodHandle MH_13;
         static final MethodHandle MH_m5;
         static final MethodHandle MH_8;
         static final MethodHandle MH_start;
         static final MethodHandle MH_step;
         static final MethodHandle MH_stepUpdateArray;
         static final MethodHandle MH_printHello;
+        static final MethodHandle MH_addCounter;
 
         static final MethodType MT_counted = methodType(String.class, String.class);
         static final MethodType MT_arrayCounted = methodType(void.class, int[].class);
         static final MethodType MT_countedPrinting = methodType(void.class);
+        static final MethodType MT_counterInit = methodType(int.class);
 
         static {
             try {
                 MH_13 = MethodHandles.constant(int.class, 13);
                 MH_m5 = MethodHandles.constant(int.class, -5);
                 MH_8 = MethodHandles.constant(int.class, 8);
                 MH_start = LOOKUP.findStatic(COUNTED, "start", MT_start);
                 MH_step = LOOKUP.findStatic(COUNTED, "step", MT_step);
                 MH_stepUpdateArray = LOOKUP.findStatic(COUNTED, "stepUpdateArray", MT_stepUpdateArray);
                 MH_printHello = LOOKUP.findStatic(COUNTED, "printHello", MT_printHello);
+                MH_addCounter = LOOKUP.findStatic(COUNTED, "addCounter", MT_addCounter);
             } catch (Exception e) {
                 throw new ExceptionInInitializerError(e);
             }
         }