use a single "empty object" shape instead of different ones for each class

Author: lukasstadler

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/PythonLanguage.java

@@ -80,6 +80,9 @@
 import com.oracle.truffle.api.nodes.ExecutableNode;
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.nodes.RootNode;
+import com.oracle.truffle.api.object.Layout;
+import com.oracle.truffle.api.object.ObjectType;
+import com.oracle.truffle.api.object.Shape;
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.source.Source.SourceBuilder;
 
@@ -103,6 +106,9 @@ public final class PythonLanguage extends TruffleLanguage<PythonContext> {
     private final NodeFactory nodeFactory;
     public final ConcurrentHashMap<Class<? extends PythonBuiltinBaseNode>, RootCallTarget> builtinCallTargetCache = new ConcurrentHashMap<>();
 
+    private static final Layout objectLayout = Layout.newLayout().build();
+    private static final Shape freshShape = objectLayout.createShape(new ObjectType());
+
     public PythonLanguage() {
         this.nodeFactory = NodeFactory.create(this);
     }
@@ -429,4 +435,8 @@ protected void initializeMultipleContexts() {
     public Object cacheCode(String filename, Supplier<PCode> createCode) {
         return cachedCode.computeIfAbsent(filename, f -> createCode.get());
     }
+
+    public static Shape freshShape() {
+        return freshShape;
+    }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/PythonBuiltinClassType.java

@@ -27,6 +27,7 @@
 
 import java.util.HashSet;
 
+import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.objects.type.LazyPythonClass;
 import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
@@ -169,7 +170,7 @@ public enum PythonBuiltinClassType implements LazyPythonClass {
     PythonBuiltinClassType(String name, String publicInModule) {
         this.name = name;
         this.publicInModule = publicInModule;
-        this.instanceShape = com.oracle.graal.python.builtins.objects.type.PythonClass.freshShape();
+        this.instanceShape = PythonLanguage.freshShape();
     }
 
     PythonBuiltinClassType(String name) {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/type/PythonClass.java

@@ -37,6 +37,7 @@
 import java.util.Set;
 import java.util.WeakHashMap;
 
+import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.objects.PNone;
 import com.oracle.graal.python.builtins.objects.cext.NativeWrappers.PythonClassNativeWrapper;
 import com.oracle.graal.python.builtins.objects.function.PFunction;
@@ -46,8 +47,6 @@
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.Truffle;
-import com.oracle.truffle.api.object.Layout;
-import com.oracle.truffle.api.object.ObjectType;
 import com.oracle.truffle.api.object.Shape;
 import com.oracle.truffle.api.utilities.CyclicAssumption;
 
@@ -56,7 +55,6 @@
  */
 public class PythonClass extends PythonObject implements LazyPythonClass {
 
-    private static final Layout objectLayout = Layout.newLayout().build();
     private final String className;
 
     @CompilationFinal(dimensions = 1) private PythonClass[] baseClasses;
@@ -83,7 +81,7 @@ public final boolean isBuiltin() {
 
     @TruffleBoundary
     public PythonClass(LazyPythonClass typeClass, String name, Shape instanceShape, PythonClass... baseClasses) {
-        super(typeClass, freshShape() /* do not inherit layout from the TypeClass */);
+        super(typeClass, PythonLanguage.freshShape() /* do not inherit layout from the TypeClass */);
         this.className = name;
 
         if (baseClasses.length == 1 && baseClasses[0] == null) {
@@ -170,10 +168,6 @@ public void lookupChanged() {
         }
     }
 
-    public static Shape freshShape() {
-        return objectLayout.createShape(new ObjectType());
-    }
-
     public Shape getInstanceShape() {
         return instanceShape;
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/object/PythonObjectFactory.java

@@ -340,7 +340,7 @@ public PythonModule createPythonModule(PythonClass cls, String name) {
     }
 
     public PythonClass createPythonClass(PythonClass metaclass, String name, PythonClass[] bases) {
-        return trace(new PythonClass(metaclass, name, PythonClass.freshShape(), bases));
+        return trace(new PythonClass(metaclass, name, PythonLanguage.freshShape(), bases));
     }
 
     public PythonNativeClass createNativeClassWrapper(Object object, PythonClass metaClass, String name, PythonClass[] pythonClasses) {