8057020: LambdaForm caches should support eviction

Reviewed-by: psandoz, jrose, shade

2 files changed, 30 insertions, 6 deletions

diff --git a/test/java/lang/invoke/LFCaching/LFCachingTestCase.java b/test/java/lang/invoke/LFCaching/LFCachingTestCase.java
index 30ba39ac2e..50a57e40c6 100644
--- a/test/java/lang/invoke/LFCaching/LFCachingTestCase.java
+++ b/test/java/lang/invoke/LFCaching/LFCachingTestCase.java
@@ -63,12 +63,17 @@ public abstract class LFCachingTestCase extends LambdaFormTestCase {
             }
 
             if (lambdaForm0 != lambdaForm1) {
-                System.err.println("Lambda form 0 toString is:");
-                System.err.println(lambdaForm0);
-                System.err.println("Lambda form 1 toString is:");
-                System.err.println(lambdaForm1);
-                throw new AssertionError("Error: Lambda forms of the two method handles"
-                        + " are not the same. LF cahing does not work");
+                // Since LambdaForm caches are based on SoftReferences, GC can cause element eviction.
+                if (noGCHappened()) {
+                    System.err.println("Lambda form 0 toString is:");
+                    System.err.println(lambdaForm0);
+                    System.err.println("Lambda form 1 toString is:");
+                    System.err.println(lambdaForm1);
+                    throw new AssertionError("Error: Lambda forms of the two method handles"
+                            + " are not the same. LF cahing does not work");
+                } else {
+                    System.err.println("LambdaForms differ, but there was a GC in between. Ignore the failure.");
+                }
             }
         } catch (IllegalAccessException | IllegalArgumentException |
                 SecurityException | InvocationTargetException ex) {
diff --git a/test/java/lang/invoke/LFCaching/LambdaFormTestCase.java b/test/java/lang/invoke/LFCaching/LambdaFormTestCase.java
index 34df1b2dd8..7b6ce2eeff 100644
--- a/test/java/lang/invoke/LFCaching/LambdaFormTestCase.java
+++ b/test/java/lang/invoke/LFCaching/LambdaFormTestCase.java
@@ -23,9 +23,12 @@
 
 import com.oracle.testlibrary.jsr292.Helper;
 import com.sun.management.HotSpotDiagnosticMXBean;
+
+import java.lang.management.GarbageCollectorMXBean;
 import java.lang.management.ManagementFactory;
 import java.lang.reflect.Method;
 import java.util.Collection;
+import java.util.List;
 import java.util.function.Function;
 import jdk.testlibrary.Utils;
 import jdk.testlibrary.TimeLimitedRunner;
@@ -50,6 +53,11 @@ public abstract class LambdaFormTestCase {
      * used to get a lambda form from a method handle.
      */
     protected final static Method INTERNAL_FORM;
+    private static final List<GarbageCollectorMXBean> gcInfo;
+
+    private static long gcCount() {
+        return gcInfo.stream().mapToLong(GarbageCollectorMXBean::getCollectionCount).sum();
+    }
 
     static {
         try {
@@ -59,6 +67,11 @@ public abstract class LambdaFormTestCase {
         } catch (Exception ex) {
             throw new Error("Unexpected exception: ", ex);
         }
+
+        gcInfo = ManagementFactory.getGarbageCollectorMXBeans();
+        if (gcInfo.size() == 0)  {
+            throw new Error("No GarbageCollectorMXBeans found.");
+        }
     }
 
     private final TestMethods testMethod;
@@ -67,6 +80,7 @@ public abstract class LambdaFormTestCase {
     private static boolean passed = true;
     private static int testCounter = 0;
     private static int failCounter = 0;
+    private long gcCountAtStart;
 
     /**
      * Test case constructor. Generates test cases with random method types for
@@ -77,12 +91,17 @@ public abstract class LambdaFormTestCase {
      */
     protected LambdaFormTestCase(TestMethods testMethod) {
         this.testMethod = testMethod;
+        this.gcCountAtStart = gcCount();
     }
 
     public TestMethods getTestMethod() {
         return testMethod;
     }
 
+    protected boolean noGCHappened() {
+        return gcCount() == gcCountAtStart;
+    }
+
     /**
      * Routine that executes a test case.
      */