A fix-up of refence counting when setting an attribute

com.oracle.truffle.r.library/src/com/oracle/truffle/r/library/stats/RMultinom.java

@@ -29,7 +29,7 @@ import com.oracle.truffle.api.profiles.ValueProfile;
 import com.oracle.truffle.r.library.stats.RandGenerationFunctions.RandomNumberProvider;
 import com.oracle.truffle.r.nodes.attributes.GetFixedAttributeNode;
 import com.oracle.truffle.r.nodes.attributes.SetFixedAttributeNode;
-import com.oracle.truffle.r.nodes.attributes.UpdateSharedAttributeNode;
+import com.oracle.truffle.r.nodes.attributes.UpdateShareableChildValueNode;
 import com.oracle.truffle.r.nodes.builtin.CastBuilder;
 import com.oracle.truffle.r.nodes.builtin.RExternalBuiltinNode;
 import com.oracle.truffle.r.nodes.function.opt.ReuseNonSharedNode;
@@ -58,7 +58,7 @@ public abstract class RMultinom extends RExternalBuiltinNode.Arg3 {
                     @Cached("create()") ReuseNonSharedNode reuseNonSharedNode,
                     @Cached("createClassProfile()") ValueProfile randGeneratorClassProfile,
                     @Cached("createBinaryProfile()") ConditionProfile hasAttributesProfile,
-                    @Cached("create()") UpdateSharedAttributeNode updateSharedAttributeNode,
+                    @Cached("create()") UpdateShareableChildValueNode updateSharedAttributeNode,
                     @Cached("createNames()") GetFixedAttributeNode getNamesNode,
                     @Cached("createDimNames()") SetFixedAttributeNode setDimNamesNode) {
         RAbstractDoubleVector nonSharedProbs = (RAbstractDoubleVector) reuseNonSharedNode.execute(probsVec);

com.oracle.truffle.r.nodes.builtin/src/com/oracle/truffle/r/nodes/builtin/base/Attr.java

@@ -40,7 +40,7 @@ import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.r.nodes.attributes.GetAttributeNode;
 import com.oracle.truffle.r.nodes.attributes.IterableAttributeNode;
 import com.oracle.truffle.r.nodes.attributes.SpecialAttributesFunctions.GetRowNamesAttributeNode;
-import com.oracle.truffle.r.nodes.attributes.UpdateSharedAttributeNode;
+import com.oracle.truffle.r.nodes.attributes.UpdateShareableChildValueNode;
 import com.oracle.truffle.r.nodes.builtin.CastBuilder;
 import com.oracle.truffle.r.nodes.builtin.RBuiltinNode;
 import com.oracle.truffle.r.runtime.RError;
@@ -67,7 +67,7 @@ public abstract class Attr extends RBuiltinNode {
 
     @CompilationFinal private String cachedName = "";
     @CompilationFinal private String cachedInternedName = "";
-    @Child private UpdateSharedAttributeNode sharedAttrUpdate = UpdateSharedAttributeNode.create();
+    @Child private UpdateShareableChildValueNode sharedAttrUpdate = UpdateShareableChildValueNode.create();
     @Child private GetAttributeNode attrAccess = GetAttributeNode.create();
     @Child private IterableAttributeNode iterAttrAccess = IterableAttributeNode.create();
 

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/access/vector/ExtractListElement.java

@@ -26,19 +26,16 @@ import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.dsl.TypeSystemReference;
 import com.oracle.truffle.api.nodes.Node;
-import com.oracle.truffle.api.profiles.ConditionProfile;
-import com.oracle.truffle.api.profiles.ValueProfile;
 import com.oracle.truffle.r.nodes.EmptyTypeSystemFlatLayout;
-import com.oracle.truffle.r.nodes.access.vector.ExtractListElementNodeGen.UpdateStateOfListElementNodeGen;
+import com.oracle.truffle.r.nodes.attributes.UpdateShareableChildValueNode;
 import com.oracle.truffle.r.runtime.data.RListBase;
-import com.oracle.truffle.r.runtime.data.RShareable;
 import com.oracle.truffle.r.runtime.data.model.RAbstractContainer;
 import com.oracle.truffle.r.runtime.data.model.RAbstractListVector;
-import com.oracle.truffle.r.runtime.data.model.RAbstractVector;
 
 /**
  * Internal node that extracts data under given index from any RAbstractContainer. In the case of
- * RListBase, it also invokes {@link UpdateStateOfListElement} on the element before returning it.
+ * RListBase, it also invokes {@link UpdateShareableChildValueNode} on the element before returning
+ * it.
  *
  * There are two reasons for why one accesses an element of a list: to peek at it, possibly
  * calculate some values from it, and then forget it. In such case, it is OK to access the element
@@ -46,9 +43,9 @@ import com.oracle.truffle.r.runtime.data.model.RAbstractVector;
  * {@link RAbstractContainer#getDataAtAsObject(int)}. However, if the object is going to be returned
  * to the user either as return value of a built-in, put inside a list, put as an attribute, or its
  * true reference count matters for some other reason, then its reference count must be put into a
- * consistent state, which is done by {@link UpdateStateOfListElement}. This node is a convenient
- * wrapper that performs the extraction as well as invocation of {@link UpdateStateOfListElement}.
- * See also the documentation of {@link RListBase}.
+ * consistent state, which is done by {@link UpdateShareableChildValueNode}. This node is a
+ * convenient wrapper that performs the extraction as well as invocation of
+ * {@link UpdateShareableChildValueNode}. See also the documentation of {@link RListBase}.
  */
 @TypeSystemReference(EmptyTypeSystemFlatLayout.class)
 public abstract class ExtractListElement extends Node {
@@ -60,7 +57,7 @@ public abstract class ExtractListElement extends Node {
     }
 
     @Specialization
-    protected Object doList(RListBase list, int index, @Cached("create()") UpdateStateOfListElement updateStateNode) {
+    protected Object doList(RListBase list, int index, @Cached("create()") UpdateShareableChildValueNode updateStateNode) {
         Object element = list.getDataAt(index);
         return updateStateNode.updateState(list, element);
     }
@@ -73,61 +70,4 @@ public abstract class ExtractListElement extends Node {
     protected static boolean isNotList(RAbstractContainer x) {
         return !(x instanceof RAbstractListVector);
     }
-
-    @TypeSystemReference(EmptyTypeSystemFlatLayout.class)
-    public abstract static class UpdateStateOfListElement extends Node {
-
-        public abstract void execute(Object owner, Object item);
-
-        /**
-         * Provides more convenient interface for the {@link #execute(Object, Object)} method.
-         */
-        public final <T> T updateState(RAbstractContainer owner, T item) {
-            execute(owner, item);
-            return item;
-        }
-
-        public static UpdateStateOfListElement create() {
-            return UpdateStateOfListElementNodeGen.create();
-        }
-
-        @Specialization
-        protected void doShareableValues(RListBase owner, RShareable value,
-                        @Cached("createClassProfile()") ValueProfile valueProfile,
-                        @Cached("createBinaryProfile()") ConditionProfile sharedValue,
-                        @Cached("createBinaryProfile()") ConditionProfile temporaryOwner) {
-            RShareable profiledValue = valueProfile.profile(value);
-            if (sharedValue.profile(profiledValue.isShared())) {
-                // it is already shared, not need to do anything
-                return;
-            }
-
-            if (temporaryOwner.profile(owner.isTemporary())) {
-                // This can happen, for example, when we immediately extract out of a temporary
-                // list that was returned by a built-in, like: strsplit(...)[[1L]]. We do not need
-                // to transition the element, it may stay temporary.
-                return;
-            }
-
-            if (profiledValue.isTemporary()) {
-                // make it at least non-shared (parent list must be also at least non-shared)
-                profiledValue.incRefCount();
-            }
-            if (owner.isShared()) {
-                // owner is shared, make the value shared too
-                profiledValue.incRefCount();
-            }
-        }
-
-        @Specialization(guards = "isFallback(owner, value)")
-        protected void doFallback(Object owner, Object value) {
-            assert !(value instanceof RShareable && owner instanceof RAbstractVector && !(owner instanceof RListBase)) : "RShareables can only live inside lists and no other vectors.";
-            // nop: either value is not RShareable, or the owner is "list" like structure with
-            // reference semantics (e.g. REnvironment)
-        }
-
-        protected static boolean isFallback(Object owner, Object value) {
-            return !(value instanceof RShareable) || !(owner instanceof RListBase);
-        }
-    }
 }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/access/vector/WriteIndexedVectorNode.java

@@ -32,7 +32,7 @@ import com.oracle.truffle.api.profiles.BranchProfile;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.profiles.LoopConditionProfile;
 import com.oracle.truffle.api.profiles.ValueProfile;
-import com.oracle.truffle.r.nodes.access.vector.ExtractListElement.UpdateStateOfListElement;
+import com.oracle.truffle.r.nodes.attributes.UpdateShareableChildValueNode;
 import com.oracle.truffle.r.nodes.function.opt.ShareObjectNode;
 import com.oracle.truffle.r.nodes.profile.AlwaysOnBranchProfile;
 import com.oracle.truffle.r.nodes.profile.IntValueProfile;
@@ -473,14 +473,14 @@ abstract class WriteIndexedVectorNode extends Node {
 
         private final boolean setListElementAsObject;
         private final boolean isReplace;
-        @Child private UpdateStateOfListElement updateStateOfListElement;
+        @Child private UpdateShareableChildValueNode updateStateOfListElement;
         @Child private ShareObjectNode shareObjectNode;
 
         WriteListAction(boolean setListElementAsObject, boolean isReplace) {
             this.setListElementAsObject = setListElementAsObject;
             this.isReplace = isReplace;
             if (!isReplace) {
-                updateStateOfListElement = UpdateStateOfListElement.create();
+                updateStateOfListElement = UpdateShareableChildValueNode.create();
             } else {
                 shareObjectNode = ShareObjectNode.create();
             }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/attributes/SetAttributeNode.java

@@ -34,6 +34,7 @@ import com.oracle.truffle.api.object.Shape;
 import com.oracle.truffle.api.profiles.BranchProfile;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.profiles.ValueProfile;
+import com.oracle.truffle.r.nodes.function.opt.ShareObjectNode;
 import com.oracle.truffle.r.runtime.RInternalError;
 import com.oracle.truffle.r.runtime.data.RAttributable;
 import com.oracle.truffle.r.runtime.data.RAttributeStorage;
@@ -148,7 +149,8 @@ public abstract class SetAttributeNode extends AttributeAccessNode {
     protected void setAttrInAttributable(RAttributable x, String name, Object value,
                     @Cached("create()") BranchProfile attrNullProfile,
                     @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                    @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                    @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                    @Cached("create()") ShareObjectNode updateRefCountNode) {
         DynamicObject attributes;
         if (attrStorageProfile.profile(x instanceof RAttributeStorage)) {
             attributes = ((RAttributeStorage) x).getAttributes();
@@ -167,6 +169,8 @@ public abstract class SetAttributeNode extends AttributeAccessNode {
         }
 
         recursive.execute(attributes, name, value);
+
+        updateRefCountNode.execute(value);
     }
 
     /**

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/attributes/SetFixedAttributeNode.java

@@ -35,6 +35,7 @@ import com.oracle.truffle.api.profiles.BranchProfile;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.profiles.ValueProfile;
 import com.oracle.truffle.r.nodes.attributes.SpecialAttributesFunctions.SetSpecialAttributeNode;
+import com.oracle.truffle.r.nodes.function.opt.ShareObjectNode;
 import com.oracle.truffle.r.runtime.RInternalError;
 import com.oracle.truffle.r.runtime.data.RAttributable;
 import com.oracle.truffle.r.runtime.data.RAttributeStorage;
@@ -126,7 +127,8 @@ public abstract class SetFixedAttributeNode extends FixedAttributeAccessNode {
     protected void setAttrInAttributable(RAttributable x, Object value,
                     @Cached("create()") BranchProfile attrNullProfile,
                     @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                    @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                    @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                    @Cached("create()") ShareObjectNode updateRefCountNode) {
         DynamicObject attributes;
         if (attrStorageProfile.profile(x instanceof RAttributeStorage)) {
             attributes = ((RAttributeStorage) x).getAttributes();
@@ -145,6 +147,8 @@ public abstract class SetFixedAttributeNode extends FixedAttributeAccessNode {
         }
 
         recursive.execute(attributes, value);
+
+        updateRefCountNode.execute(value);
     }
 
 }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/attributes/SpecialAttributesFunctions.java

@@ -31,6 +31,7 @@ import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.profiles.LoopConditionProfile;
 import com.oracle.truffle.api.profiles.ValueProfile;
 import com.oracle.truffle.r.nodes.attributes.SpecialAttributesFunctionsFactory.GetDimAttributeNodeGen;
+import com.oracle.truffle.r.nodes.function.opt.ShareObjectNode;
 import com.oracle.truffle.r.runtime.RError;
 import com.oracle.truffle.r.runtime.RInternalError;
 import com.oracle.truffle.r.runtime.RRuntime;
@@ -318,7 +319,8 @@ public final class SpecialAttributesFunctions {
                         @Cached("create()") SetDimNamesAttributeNode setDimNamesNode,
                         @Cached("create()") BranchProfile attrNullProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
             RVector<?> xProfiled = xTypeProfile.profile(x);
             if (newNames.getLength() > xProfiled.getLength()) {
                 namesTooLongProfile.enter();
@@ -342,7 +344,7 @@ public final class SpecialAttributesFunctions {
                     return;
                 }
 
-                super.setAttrInAttributable(xProfiled, newNames, attrNullProfile, attrStorageProfile, xTypeProfile);
+                super.setAttrInAttributable(xProfiled, newNames, attrNullProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
             }
         }
 
@@ -454,7 +456,8 @@ public final class SpecialAttributesFunctions {
         protected void setOneDimInVector(RVector<?> x, int dim,
                         @Cached("create()") BranchProfile attrNullProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
             RAbstractContainer xProfiled = contArgClassProfile.profile(x);
 
             int[] dims = new int[]{dim};
@@ -467,17 +470,19 @@ public final class SpecialAttributesFunctions {
                 attrNullProfile.enter();
                 attrs = RAttributesLayout.createDim(dimVec);
                 xProfiled.initAttributes(attrs);
+                updateRefCountNode.execute(dimVec);
                 return;
             }
 
-            super.setAttrInAttributable(x, dimVec, attrNullProfile, attrStorageProfile, xTypeProfile);
+            super.setAttrInAttributable(x, dimVec, attrNullProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
         }
 
         @Specialization(insertBefore = "setAttrInAttributable")
         protected void setDimsInVector(RVector<?> x, RAbstractIntVector dims,
                         @Cached("create()") BranchProfile attrNullProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
             RAbstractContainer xProfiled = contArgClassProfile.profile(x);
             verifyDimensions(xProfiled.getLength(), dims);
 
@@ -486,10 +491,11 @@ public final class SpecialAttributesFunctions {
                 attrNullProfile.enter();
                 attrs = RAttributesLayout.createDim(dims);
                 xProfiled.initAttributes(attrs);
+                updateRefCountNode.execute(dims);
                 return;
             }
 
-            super.setAttrInAttributable(x, dims, attrNullProfile, attrStorageProfile, xTypeProfile);
+            super.setAttrInAttributable(x, dims, attrNullProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
         }
 
         @Specialization(insertBefore = "setAttrInAttributable")
@@ -683,7 +689,8 @@ public final class SpecialAttributesFunctions {
                         @Cached("create()") BranchProfile resizeDimsProfile,
                         @Cached("create()") BranchProfile attrNullProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
             int[] dimensions = getDimNode.getDimensions(x);
             if (dimensions == null) {
                 nullDimsProfile.enter();
@@ -727,10 +734,11 @@ public final class SpecialAttributesFunctions {
             if (x.getAttributes() == null) {
                 attrNullProfile.enter();
                 x.initAttributes(RAttributesLayout.createDimNames(resDimNames));
+                updateRefCountNode.execute(resDimNames);
                 return;
             }
 
-            super.setAttrInAttributable(x, resDimNames, attrNullProfile, attrStorageProfile, xTypeProfile);
+            super.setAttrInAttributable(x, resDimNames, attrNullProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
         }
 
         private static boolean isValidDimLength(RStringVector x, int expectedDim) {
@@ -824,13 +832,15 @@ public final class SpecialAttributesFunctions {
         protected void setRowNamesInVector(RVector<?> x, RAbstractVector newRowNames,
                         @Cached("create()") BranchProfile attrNullProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
             if (x.getAttributes() == null) {
                 attrNullProfile.enter();
                 x.initAttributes(RAttributesLayout.createRowNames(newRowNames));
+                updateRefCountNode.execute(newRowNames);
                 return;
             }
-            setAttrInAttributable(x, newRowNames, attrNullProfile, attrStorageProfile, xTypeProfile);
+            setAttrInAttributable(x, newRowNames, attrNullProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
         }
 
         @Specialization(insertBefore = "setAttrInAttributable")
@@ -923,8 +933,9 @@ public final class SpecialAttributesFunctions {
                         @Cached("createBinaryProfile()") ConditionProfile nullClassProfile,
                         @Cached("createBinaryProfile()") ConditionProfile notNullClassProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
-            handleVector(vector, null, removeClassAttrNode, initAttrProfile, nullAttrProfile, nullClassProfile, notNullClassProfile, attrStorageProfile, xTypeProfile);
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
+            handleVector(vector, null, removeClassAttrNode, initAttrProfile, nullAttrProfile, nullClassProfile, notNullClassProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
         }
 
         @Specialization(insertBefore = "setAttrInAttributable")
@@ -935,7 +946,8 @@ public final class SpecialAttributesFunctions {
                         @Cached("createBinaryProfile()") ConditionProfile nullClassProfile,
                         @Cached("createBinaryProfile()") ConditionProfile notNullClassProfile,
                         @Cached("createBinaryProfile()") ConditionProfile attrStorageProfile,
-                        @Cached("createClassProfile()") ValueProfile xTypeProfile) {
+                        @Cached("createClassProfile()") ValueProfile xTypeProfile,
+                        @Cached("create()") ShareObjectNode updateRefCountNode) {
 
             DynamicObject attrs = vector.getAttributes();
             boolean initializeAttrs = initAttrProfile.profile(attrs == null && classAttr != null && classAttr.getLength() != 0);
@@ -943,6 +955,7 @@ public final class SpecialAttributesFunctions {
                 nullAttrProfile.enter();
                 attrs = RAttributesLayout.createClass(classAttr);
                 vector.initAttributes(attrs);
+                updateRefCountNode.execute(classAttr);
             }
             if (nullClassProfile.profile(attrs != null && (classAttr == null || classAttr.getLength() == 0))) {
                 removeAttributeMapping(vector, attrs, removeClassAttrNode);
@@ -953,7 +966,7 @@ public final class SpecialAttributesFunctions {
                         // TODO: Isn't this redundant when the same operation is done after the
                         // loop?
                         if (!initializeAttrs) {
-                            super.setAttrInAttributable(vector, classAttr, nullAttrProfile, attrStorageProfile, xTypeProfile);
+                            super.setAttrInAttributable(vector, classAttr, nullAttrProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
                         }
                         // setClassAttrNode.execute(attrs, classAttr);
                         if (vector.getElementClass() != RInteger.class) {
@@ -971,7 +984,7 @@ public final class SpecialAttributesFunctions {
                 }
 
                 if (!initializeAttrs) {
-                    super.setAttrInAttributable(vector, classAttr, nullAttrProfile, attrStorageProfile, xTypeProfile);
+                    super.setAttrInAttributable(vector, classAttr, nullAttrProfile, attrStorageProfile, xTypeProfile, updateRefCountNode);
                 }
             }
         }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/attributes/UpdateSharedAttributeNode.java → com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/attributes/UpdateShareableChildValueNode.java

@@ -27,11 +27,12 @@ import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.api.profiles.ValueProfile;
 import com.oracle.truffle.r.runtime.data.RShareable;
+import com.oracle.truffle.r.runtime.data.RSharingAttributeStorage;
 import com.oracle.truffle.r.runtime.nodes.RBaseNode;
 
-public abstract class UpdateSharedAttributeNode extends RBaseNode {
+public abstract class UpdateShareableChildValueNode extends RBaseNode {
 
-    protected UpdateSharedAttributeNode() {
+    protected UpdateShareableChildValueNode() {
     }
 
     public abstract void execute(Object owner, Object attrValue);
@@ -41,12 +42,13 @@ public abstract class UpdateSharedAttributeNode extends RBaseNode {
         return item;
     }
 
-    public static UpdateSharedAttributeNode create() {
-        return UpdateSharedAttributeNodeGen.create();
+    public static UpdateShareableChildValueNode create() {
+        return UpdateShareableChildValueNodeGen.create();
     }
 
     @Specialization
     protected void doShareableValues(RShareable owner, RShareable value,
+                    @Cached("createClassProfile()") ValueProfile ownerProfile,
                     @Cached("createClassProfile()") ValueProfile valueProfile,
                     @Cached("createBinaryProfile()") ConditionProfile sharedValue,
                     @Cached("createBinaryProfile()") ConditionProfile temporaryOwner) {
@@ -56,17 +58,34 @@ public abstract class UpdateSharedAttributeNode extends RBaseNode {
             return;
         }
 
+        if (owner instanceof RSharingAttributeStorage) {
+            // monomorphic invocations of the owner
+            RSharingAttributeStorage shOwner = (RSharingAttributeStorage) owner;
+            incRef(shOwner, profiledValue, temporaryOwner);
+        } else {
+            // invoking a type-profiled owner
+            RShareable ownerProfiled = ownerProfile.profile(owner);
+            incRef(ownerProfiled, profiledValue, temporaryOwner);
+        }
+    }
+
+    private static void incRef(RShareable owner, RShareable value, ConditionProfile temporaryOwner) {
         if (temporaryOwner.profile(owner.isTemporary())) {
+            // This can happen, for example, when we immediately extract out of a temporary
+            // list that was returned by a built-in, like: strsplit(...)[[1L]]. We do not need
+            // to transition the element, it may stay temporary.
             return;
         }
 
-        if (profiledValue.isTemporary()) {
+        // the owner is at least non-shared
+
+        if (value.isTemporary()) {
             // make it at least non-shared (the owner must be also at least non-shared)
-            profiledValue.incRefCount();
+            value.incRefCount();
         }
         if (owner.isShared()) {
             // owner is shared, make the attribute value shared too
-            profiledValue.incRefCount();
+            value.incRefCount();
         }
     }
 

com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/builtins/TestBuiltin_attrassign.java

@@ -98,6 +98,12 @@ public class TestBuiltin_attrassign extends TestBase {
         assertEval("argv <- list(structure(c(0, -187, -34, 0, 165, 0, -95, 121, 107, 0, 41, 0, 0, 93, 0), .Dim = c(5L, 3L)), 'dimnames', value = NULL);`attr<-`(argv[[1]],argv[[2]],argv[[3]]);");
     }
 
+    @Test
+    public void testRefCount() {
+        assertEval("x <- c(1,2); attr(x, \"foo\") <- c(\"a\",\"b\"); y <- x; attr(x,\"foo\")[[1]] <- \"c\"; y");
+        assertEval("x <- c(1,2,3); y <- 42; attr(y, 'at') <- x; x[[1]] <- 2; attr(y, 'at')");
+    }
+
     @Test
     public void testArgsCasts() {
         assertEval(Output.IgnoreErrorContext, "x<-42; attr(x, NULL) <- NULL");

com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/builtins/TestBuiltin_list.java

@@ -347,6 +347,11 @@ public class TestBuiltin_list extends TestBase {
                         "argv <- list(ANY = structure(function (x, y = NULL) .Internal(crossprod(x, y)), target = structure('ANY', class = structure('signature', package = 'methods'), .Names = 'x', package = 'methods'), defined = structure('ANY', class = structure('signature', package = 'methods'), .Names = 'x', package = 'methods'), generic = structure('crossprod', package = 'base'), class = structure('derivedDefaultMethod', package = 'methods')));list(argv[[1]]);");
     }
 
+    @Test
+    public void testRefCount() {
+        assertEval("{ l <- list(a=c(1,2)); l2 <- l; l$a[[1]] <- 3; l2 }");
+    }
+
     @Test
     public void testList() {
         assertEval("{ list(a=1, b=2) }");