Fix: consistently use NULL handle delegate

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/hpy/GraalHPyHandle.java

@@ -69,6 +69,7 @@
 public final class GraalHPyHandle implements TruffleObject {
     private static final int UNINITIALIZED = Integer.MIN_VALUE;
 
+    public static final Object NULL_HANDLE_DELEGATE = PNone.NO_VALUE;
     public static final GraalHPyHandle NULL_HANDLE = new GraalHPyHandle();
     public static final String I = "_i";
 
@@ -87,7 +88,7 @@ public final class GraalHPyHandle implements TruffleObject {
     private int id;
 
     private GraalHPyHandle() {
-        this.delegate = PNone.NO_VALUE;
+        this.delegate = NULL_HANDLE_DELEGATE;
         this.id = 0;
     }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/hpy/GraalHPyNodes.java

@@ -1187,7 +1187,7 @@ Object doHandleAllocated(GraalHPyContext hpyContext, GraalHPyHandle handle) {
         @Specialization(guards = "isBoxedNullHandle(bits)")
         @SuppressWarnings("unused")
         static Object doNullLong(GraalHPyContext hpyContext, long bits) {
-            return null;
+            return GraalHPyHandle.NULL_HANDLE_DELEGATE;
         }
 
         @Specialization(guards = {"!isBoxedNullHandle(bits)", "isBoxedHandle(bits)"})
@@ -1224,7 +1224,7 @@ static long asPointer(Object handle, InteropLibrary lib) {
         static Object doNullOther(GraalHPyContext hpyContext, Object value,
                         @Shared("lib") @CachedLibrary(limit = "2") InteropLibrary lib,
                         @Bind("asPointer(value, lib)") long bits) {
-            return null;
+            return GraalHPyHandle.NULL_HANDLE_DELEGATE;
         }
 
         @Specialization(guards = {"!isLong(value)", "!isHPyHandle(value)", "!isBoxedNullHandle(bits)", "isBoxedHandle(bits)"})
@@ -1289,7 +1289,7 @@ static Object doValidHandle(GraalHPyContext hpyContext, GraalHPyHandle handle) {
         @Specialization(guards = "isBoxedNullHandle(bits)")
         @SuppressWarnings("unused")
         static Object doNullLong(GraalHPyContext hpyContext, long bits) {
-            return PNone.NO_VALUE;
+            return GraalHPyHandle.NULL_HANDLE_DELEGATE;
         }
 
         @Specialization(guards = {"!isBoxedNullHandle(bits)", "isBoxedHandle(bits)"})
@@ -1321,7 +1321,7 @@ static long asPointer(Object handle, InteropLibrary lib) {
         static Object doNullOther(@SuppressWarnings("unused") GraalHPyContext hpyContext, @SuppressWarnings("unused") Object value,
                         @Shared("lib") @CachedLibrary(limit = "2") @SuppressWarnings("unused") InteropLibrary lib,
                         @Bind("asPointer(value, lib)") @SuppressWarnings("unused") long bits) {
-            return PNone.NO_VALUE;
+            return GraalHPyHandle.NULL_HANDLE_DELEGATE;
         }
 
         @Specialization(guards = {"!isLong(value)", "!isHPyHandle(value)", "!isBoxedNullHandle(bits)", "isBoxedHandle(bits)"})

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/hpy/HPyExternalFunctionNodes.java

@@ -1087,7 +1087,7 @@ Object doLongNull(PythonThreadState pythonThreadState, @SuppressWarnings("unused
                         @Cached PythonObjectFactory factory,
                         @Cached PRaiseNode raiseNode) {
             Object delegate = closeAndGetHandleNode.execute(nativeContext, value);
-            checkFunctionResult(name, isNullProfile.profile(delegate == null), pythonThreadState, raiseNode, factory);
+            checkFunctionResult(name, isNullProfile.profile(delegate == GraalHPyHandle.NULL_HANDLE_DELEGATE), pythonThreadState, raiseNode, factory);
             return delegate;
         }
     }