GROOVY-10307: Improve invokedynamic performance with optimized caching

src/main/java/org/codehaus/groovy/vmplugin/v8/CacheableCallSite.java

@@ -124,4 +124,21 @@ public MethodHandle getFallbackTarget() {
     public void setFallbackTarget(MethodHandle fallbackTarget) {
         this.fallbackTarget = fallbackTarget;
     }
+
+    /**
+     * Clear the cache entirely. Called when metaclass changes to ensure
+     * stale method handles are discarded.
+     */
+    public void clearCache() {
+        // Clear the latest hit reference
+        latestHitMethodHandleWrapperSoftReference = null;
+
+        // Clear the LRU cache
+        synchronized (lruCache) {
+            lruCache.clear();
+        }
+
+        // Reset fallback count
+        fallbackCount.set(0);
+    }
 }

src/main/java/org/codehaus/groovy/vmplugin/v8/IndyInterface.java

@@ -32,7 +32,10 @@
 import java.lang.invoke.MethodType;
 import java.lang.invoke.MutableCallSite;
 import java.lang.invoke.SwitchPoint;
+import java.lang.ref.WeakReference;
 import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.logging.Level;
@@ -168,24 +171,55 @@ public static CallType fromCallSiteName(String callSiteName) {
     }
 
     protected static SwitchPoint switchPoint = new SwitchPoint();
+
+    /**
+     * Weak set of all CacheableCallSites. Used to invalidate caches when metaclass changes.
+     * Uses WeakReferences so call sites can be garbage collected when no longer referenced.
+     */
+    private static final Set<WeakReference<CacheableCallSite>> ALL_CALL_SITES = ConcurrentHashMap.newKeySet();
 
     static {
         GroovySystem.getMetaClassRegistry().addMetaClassRegistryChangeEventListener(cmcu -> invalidateSwitchPoints());
     }
+
+    /**
+     * Register a call site for cache invalidation when metaclass changes.
+     */
+    static void registerCallSite(CacheableCallSite callSite) {
+        ALL_CALL_SITES.add(new WeakReference<>(callSite));
+    }
 
     /**
-     * Callback for constant metaclass update change
+     * Callback for constant metaclass update change.
+     * Invalidates all call site caches to ensure metaclass changes are visible.
      */
     protected static void invalidateSwitchPoints() {
         if (LOG_ENABLED) {
-            LOG.info("invalidating switch point");
+            LOG.info("invalidating switch point and call site caches");
         }
 
         synchronized (IndyInterface.class) {
             SwitchPoint old = switchPoint;
             switchPoint = new SwitchPoint();
             SwitchPoint.invalidateAll(new SwitchPoint[]{old});
         }
+
+        // Invalidate all call site caches and reset targets to default (cache lookup)
+        // This ensures metaclass changes are visible without using expensive switchpoint guards
+        ALL_CALL_SITES.removeIf(ref -> {
+            CacheableCallSite cs = ref.get();
+            if (cs == null) {
+                return true; // Remove garbage collected references
+            }
+            // Reset target to default (fromCache) so next call goes through cache lookup
+            MethodHandle defaultTarget = cs.getDefaultTarget();
+            if (defaultTarget != null && cs.getTarget() != defaultTarget) {
+                cs.setTarget(defaultTarget);
+            }
+            // Clear the cache so stale method handles are discarded
+            cs.clearCache();
+            return false;
+        });
     }
 
     /**
@@ -230,6 +264,9 @@ private static CallSite realBootstrap(Lookup caller, String name, int callID, Me
         mc.setTarget(mh);
         mc.setDefaultTarget(mh);
         mc.setFallbackTarget(makeFallBack(mc, sender, name, callID, type, safe, thisCall, spreadCall));
+
+        // Register for cache invalidation on metaclass changes
+        registerCallSite(mc);
 
         return mc;
     }

src/main/java/org/codehaus/groovy/vmplugin/v8/Selector.java

@@ -33,6 +33,7 @@
 import groovy.lang.MissingMethodException;
 import groovy.transform.Internal;
 import org.apache.groovy.runtime.ObjectUtil;
+import org.apache.groovy.util.SystemUtil;
 import org.codehaus.groovy.GroovyBugError;
 import org.codehaus.groovy.reflection.CachedField;
 import org.codehaus.groovy.reflection.CachedMethod;
@@ -940,9 +941,18 @@ public void setGuards(Object receiver) {
                 }
             }
 
-            // handle constant metaclass and category changes
-            handle = switchPoint.guardWithTest(handle, fallback);
-            if (LOG_ENABLED) LOG.info("added switch point guard");
+            // Skip the global switchpoint guard by default.
+            // The switchpoint causes ALL call sites to fail when ANY metaclass changes.
+            // In Grails and similar frameworks with frequent metaclass changes, this causes
+            // massive guard failures and performance degradation.
+            // The other guards (metaclass identity, class receiver, category) should be
+            // sufficient, combined with cache invalidation on metaclass changes.
+            // 
+            // If you need strict metaclass change detection, set groovy.indy.switchpoint.guard=true
+            if (SystemUtil.getBooleanSafe("groovy.indy.switchpoint.guard")) {
+                handle = switchPoint.guardWithTest(handle, fallback);
+                if (LOG_ENABLED) LOG.info("added switch point guard");
+            }
 
             java.util.function.Predicate<Class<?>> nonFinalOrNullUnsafe = (t) -> {
                 return !Modifier.isFinal(t.getModifiers())