[GR-2798] Fix memleak caused by the language closure cache.

PullRequest: fastr/1222

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/control/ReplacementNode.java

@@ -160,8 +160,7 @@ abstract class ReplacementNode extends OperatorNode {
     static RLanguage getLanguage(WriteVariableNode wvn) {
         Node parent = wvn.getParent();
         if (parent instanceof ReplacementNode) {
-            Closure closure = RContext.getInstance().languageClosureCache.getOrCreateLanguageClosure((ReplacementNode) parent);
-            return RDataFactory.createLanguage(closure);
+            return RDataFactory.createLanguage(Closure.createLanguageClosure((ReplacementNode) parent));
         }
         return null;
     }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/function/FunctionDefinitionNode.java

@@ -23,6 +23,7 @@
 package com.oracle.truffle.r.nodes.function;
 
 import java.util.ArrayList;
+import java.util.IdentityHashMap;
 import java.util.List;
 
 import com.oracle.truffle.api.Assumption;
@@ -70,6 +71,7 @@ import com.oracle.truffle.r.runtime.builtins.RBuiltinDescriptor;
 import com.oracle.truffle.r.runtime.context.RContext;
 import com.oracle.truffle.r.runtime.context.TruffleRLanguage;
 import com.oracle.truffle.r.runtime.data.Closure;
+import com.oracle.truffle.r.runtime.data.ClosureCache;
 import com.oracle.truffle.r.runtime.data.RNull;
 import com.oracle.truffle.r.runtime.data.RPairList;
 import com.oracle.truffle.r.runtime.env.frame.FrameSlotChangeMonitor;
@@ -84,7 +86,7 @@ import com.oracle.truffle.r.runtime.nodes.RSyntaxLookup;
 import com.oracle.truffle.r.runtime.nodes.RSyntaxNode;
 import com.oracle.truffle.r.runtime.nodes.RSyntaxVisitor;
 
-public final class FunctionDefinitionNode extends RRootNode implements RSyntaxNode, RSyntaxFunction {
+public final class FunctionDefinitionNode extends RRootNode implements RSyntaxNode, RSyntaxFunction, ClosureCache {
 
     private final FormalArguments formalArguments;
 
@@ -135,6 +137,8 @@ public final class FunctionDefinitionNode extends RRootNode implements RSyntaxNo
      */
     private final ConditionProfile returnTopLevelProfile = ConditionProfile.createBinaryProfile();
 
+    @CompilationFinal private IdentityHashMap<RNode, Closure> languageClosureCache;
+
     public static FunctionDefinitionNode create(TruffleRLanguage language, SourceSection src, FrameDescriptor frameDesc, SourceSection[] argSourceSections, SaveArgumentsNode saveArguments,
                     RSyntaxNode body,
                     FormalArguments formals, String name, PostProcessArgumentsNode argPostProcess) {
@@ -368,8 +372,7 @@ public final class FunctionDefinitionNode extends RRootNode implements RSyntaxNo
                                     CompilerDirectives.transferToInterpreter();
                                     RInternalError.shouldNotReachHere("unexpected type for on.exit entry: " + expr.car());
                                 }
-                                Closure closure = RContext.getInstance().languageClosureCache.getOrCreateLanguageClosure((RNode) expr.car());
-                                onExitExpressionCache.execute(frame, closure);
+                                onExitExpressionCache.execute(frame, getOrCreateLanguageClosure((RNode) expr.car()));
                             }
                         }
                     } catch (ReturnException ex) {
@@ -554,4 +557,13 @@ public final class FunctionDefinitionNode extends RRootNode implements RSyntaxNo
         }
         return handlerStackSlot;
     }
+
+    @Override
+    public IdentityHashMap<RNode, Closure> getContent() {
+        if (languageClosureCache == null) {
+            CompilerDirectives.transferToInterpreterAndInvalidate();
+            languageClosureCache = new IdentityHashMap<>();
+        }
+        return languageClosureCache;
+    }
 }

com.oracle.truffle.r.runtime/src/com/oracle/truffle/r/runtime/data/LanguageClosureCache.java

@@ -22,6 +22,7 @@
  */
 package com.oracle.truffle.r.runtime.data;
 
+import java.lang.ref.WeakReference;
 import java.util.WeakHashMap;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
@@ -29,7 +30,7 @@ import com.oracle.truffle.r.runtime.nodes.RNode;
 
 public class LanguageClosureCache {
 
-    private final WeakHashMap<RNode, Closure> cache = new WeakHashMap<>();
+    private final WeakHashMap<RNode, WeakReference<Closure>> cache = new WeakHashMap<>();
 
     /**
      * @param expr
@@ -42,10 +43,11 @@ public class LanguageClosureCache {
             return null;
         }
 
-        Closure result = cache.get(expr);
+        WeakReference<Closure> weakRef = cache.get(expr);
+        Closure result = weakRef != null ? weakRef.get() : null;
         if (result == null) {
             result = Closure.createLanguageClosure(expr);
-            cache.put(expr, result);
+            cache.put(expr, new WeakReference<>(result));
         }
         return result;
     }