Tidy up of marking service and nodes.

Author: aardvark179

src/main/java/org/truffleruby/cext/ValueWrapper.java

@@ -118,6 +118,7 @@ protected static long asPointer(ValueWrapper wrapper,
 
         if (ValueWrapperManager.isTaggedObject(handle)) {
             taggedObjectProfile.enter();
+
             keepAliveNode.execute(wrapper);
         }
 

src/main/java/org/truffleruby/core/MarkingService.java

@@ -82,32 +82,6 @@ public boolean hasSingleKeptObject() {
             return current.preservedObject != null && current.preservedObjects == null;
         }
 
-        public void keepObject(ValueWrapper value) {
-            if (current.preservedObject == null) {
-                current.preservedObject = value;
-            } else if (current.preservedObject != value) {
-                keepObjectOnList(value);
-            }
-        }
-
-        @TruffleBoundary
-        private void keepObjectOnList(ValueWrapper value) {
-            if (current.preservedObjects == null) {
-                current.preservedObjects = new ArrayList<>();
-                current.preservedObjects.add(current.preservedObject);
-            }
-            current.preservedObjects.add(value);
-        }
-
-        public ArrayList<ValueWrapper> getKeptObjects() {
-            assert current.previous != null;
-
-            if (current.preservedObjects == null) {
-                current.preservedObjects = new ArrayList<>();
-            }
-            return current.preservedObjects;
-        }
-
         public void markOnExitObject(ValueWrapper value) {
             if (current.markOnExitObject == null) {
                 current.markOnExitObject = value;
@@ -127,10 +101,8 @@ private void markOnExitObjectOnList(ValueWrapper value) {
 
         public ArrayList<ValueWrapper> getMarkOnExitObjects() {
             assert current.previous != null;
+            assert current.markOnExitObjects != null;
 
-            if (current.markOnExitObjects == null) {
-                current.markOnExitObjects = new ArrayList<>();
-            }
             return current.markOnExitObjects;
         }
 

src/main/java/org/truffleruby/core/MarkingServiceNodes.java

@@ -14,10 +14,14 @@
 import org.truffleruby.language.RubyBaseNode;
 import org.truffleruby.language.dispatch.DispatchNode;
 
+import java.util.ArrayList;
+
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.GenerateUncached;
 import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.profiles.ConditionProfile;
 
 public class MarkingServiceNodes {
 
@@ -26,13 +30,38 @@ public abstract static class KeepAliveNode extends RubyBaseNode {
 
         public abstract void execute(ValueWrapper object);
 
-        @Specialization
-        protected void executeAddToList(ValueWrapper object) {
-            addToList(getLanguage().getCurrentThread().getCurrentFiber().extensionCallStack, object);
+        @Specialization(guards = "!stack.hasKeptObjects()")
+        protected void keepFirstObject(ValueWrapper object,
+                @Bind("getStack(object)") ExtensionCallStack stack) {
+            stack.current.preservedObject = object;
         }
 
-        protected void addToList(ExtensionCallStack stack, ValueWrapper object) {
-            stack.keepObject(object);
+        @Specialization(guards = "stack.hasSingleKeptObject()")
+        protected void keepCreatingList(ValueWrapper object,
+                @Bind("getStack(object)") ExtensionCallStack stack,
+                @Cached ConditionProfile sameObjectProfile) {
+            if (sameObjectProfile.profile(object != stack.current.preservedObject)) {
+                createKeptList(object, stack);
+            }
+        }
+
+        @Specialization(guards = { "stack.hasKeptObjects()", "!stack.hasSingleKeptObject()" })
+        @TruffleBoundary
+        protected void keepAddingToList(ValueWrapper object,
+                @Bind("getStack(object)") ExtensionCallStack stack) {
+            stack.current.preservedObjects.add(object);
+        }
+
+        @TruffleBoundary
+        private void createKeptList(ValueWrapper object, ExtensionCallStack stack) {
+            stack.current.preservedObjects = new ArrayList<>();
+            stack.current.preservedObjects.add(stack.current.preservedObject);
+            stack.current.preservedObjects.add(object);
+        }
+
+        // We take a parameter so that the bind isn't considered cacheable.
+        protected ExtensionCallStack getStack(ValueWrapper object) {
+            return getLanguage().getCurrentThread().getCurrentFiber().extensionCallStack;
         }
     }