Mercurial > hg > truffle
changeset 5632:4d0f01e9f31b
Added detailed test cases for the closed world analysis. Add support for ValueProxyNode, CheckCastNode. Fix modelling of arrays.
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.boot.test/src/com/oracle/graal/boot/BigBangTest.java Sat Jun 16 02:19:38 2012 +0200 @@ -0,0 +1,65 @@ +/* + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package com.oracle.graal.boot; + +import org.junit.*; + +public class BigBangTest { + + @Test + public void helloWorldTest() { + BootImageGenerator generator = new BootImageGenerator(); + generator.addEntryMethod(TestPrograms.class, "helloWorldTest"); + Assert.assertArrayEquals(generator.getBigBang().printState(), new int[]{3, 118, 58, 21}); + } + + @Test + public void formattedOutputTest() { + BootImageGenerator generator = new BootImageGenerator(); + generator.addEntryMethod(TestPrograms.class, "formattedOutputTest"); + Assert.assertArrayEquals(generator.getBigBang().printState(), new int[]{15, 979, 346, 98}); + } + + + @Test + public void newTest() { + BootImageGenerator generator = new BootImageGenerator(); + generator.addEntryMethod(TestPrograms.class, "newTest"); + Assert.assertArrayEquals(generator.getBigBang().printState(), new int[]{0, 3, 0, 0}); + } + + + @Test + public void arraycopyTest() { + BootImageGenerator generator = new BootImageGenerator(); + generator.addEntryMethod(TestPrograms.class, "arraycopyTest"); + Assert.assertArrayEquals(generator.getBigBang().printState(), new int[]{2, 6, 0, 0}); + } + + @Test + public void arrayListTest() { + BootImageGenerator generator = new BootImageGenerator(); + generator.addEntryMethod(TestPrograms.class, "arrayListTest"); + Assert.assertArrayEquals(generator.getBigBang().printState(), new int[]{2, 20, 3, 2}); + } +}
--- a/graal/com.oracle.graal.boot.test/src/com/oracle/graal/boot/HelloWorldTest.java Sat Jun 16 02:17:44 2012 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,34 +0,0 @@ -/* - * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * This code is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 only, as - * published by the Free Software Foundation. - * - * This code is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License - * version 2 for more details (a copy is included in the LICENSE file that - * accompanied this code). - * - * You should have received a copy of the GNU General Public License version - * 2 along with this work; if not, write to the Free Software Foundation, - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. - * - * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - */ -package com.oracle.graal.boot; - -import com.oracle.graal.boot.test.helloworld.*; - - -public class HelloWorldTest { - public static void main(String[] args) { - BootImageGenerator generator = new BootImageGenerator(); - generator.addEntryMethod(HelloWorldTestProgram.class, "main", String[].class); - generator.printState(); - } -}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.boot.test/src/com/oracle/graal/boot/TestPrograms.java Sat Jun 16 02:19:38 2012 +0200 @@ -0,0 +1,60 @@ +/* + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package com.oracle.graal.boot; + +import java.util.*; + +public class TestPrograms { + public static void helloWorldTest() { + System.out.println("Hello world!"); + } + + public static void formattedOutputTest() { + System.out.printf("%s %s!", "Hello", "world"); + } + + @SuppressWarnings("unused") + public static void newTest() { + Integer x = new Integer(5); + } + + public static void arraycopyTest() { + Object[] arr = new Object[1]; + arr[0] = new TestObject(); + TestObject[] newArr = Arrays.copyOf(arr, 1, TestObject[].class); + newArr[0].testMethod(); + } + + @SuppressWarnings("unchecked") + public static void arrayListTest() { + ArrayList list = new ArrayList(); + list.add(new TestObject()); + TestObject[] newArr = (TestObject[]) list.toArray(new TestObject[0]); + newArr[0].testMethod(); + } + + public static class TestObject { + public void testMethod() { + } + } +}
--- a/graal/com.oracle.graal.boot.test/src/com/oracle/graal/boot/test/helloworld/HelloWorldTestProgram.java Sat Jun 16 02:17:44 2012 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,29 +0,0 @@ -/* - * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * This code is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 only, as - * published by the Free Software Foundation. - * - * This code is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License - * version 2 for more details (a copy is included in the LICENSE file that - * accompanied this code). - * - * You should have received a copy of the GNU General Public License version - * 2 along with this work; if not, write to the Free Software Foundation, - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. - * - * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - */ -package com.oracle.graal.boot.test.helloworld; - -public class HelloWorldTestProgram { - public static void main(String[] args) { - System.out.println("Hello world!"); - } -}
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/BigBang.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/BigBang.java Sat Jun 16 02:19:38 2012 +0200 @@ -35,7 +35,7 @@ public class BigBang { - private static final int THREADS = 1; + private static final int THREADS = 4; private MetaAccessProvider metaAccessProvider; private int postedOperationCount; @@ -83,20 +83,26 @@ if (node instanceof PhiNode) { PhiNode phiNode = (PhiNode) node; resultElement = new PhiElement(phiNode); + } else if (node instanceof CheckCastNode) { + CheckCastNode checkCastNode = (CheckCastNode) node; + resultElement = new CastElement(checkCastNode); + } else if (node instanceof ValueProxyNode) { + ValueProxyNode proxyNode = (ValueProxyNode) node; + resultElement = new ProxyElement(proxyNode); } else if (node instanceof StoreFieldNode) { StoreFieldNode storeFieldNode = (StoreFieldNode) node; resultElement = getProcessedField(storeFieldNode.field()); } else if (node instanceof StoreIndexedNode) { StoreIndexedNode storeIndexedNode = (StoreIndexedNode) node; if (storeIndexedNode.elementKind() == Kind.Object) { - resultElement = getProcessedArrayType(storeIndexedNode.array().stamp().declaredType()); + resultElement = getProcessedArrayType(metaAccessProvider.getResolvedJavaType(Object[].class)); } } else if (node instanceof ReturnNode) { ReturnNode returnNode = (ReturnNode) node; ResolvedJavaMethod method = ((StructuredGraph) returnNode.graph()).method(); resultElement = getProcessedMethod(method); } else { - if (node instanceof FrameState || node instanceof MonitorEnterNode || node instanceof MonitorExitNode || node instanceof LoadFieldNode || node instanceof IsNullNode) { + if (node instanceof FrameState || node instanceof MonitorEnterNode || node instanceof MonitorExitNode || node instanceof LoadFieldNode || node instanceof IsNullNode || node instanceof InstanceOfNode) { // OK. } else { System.out.println("Unknown sink - black hole? " + node); @@ -123,7 +129,9 @@ } public synchronized void registerSourceCallTargetNode(MethodCallTargetNode methodCallTargetNode) { - sinkMap.put(methodCallTargetNode, new InvokeElement(methodCallTargetNode)); + InvokeElement invokeElement = new InvokeElement(methodCallTargetNode); + sinkMap.put(methodCallTargetNode, invokeElement); + invokeElement.expandStaticMethod(this); } public synchronized void registerSourceNode(Node node) { @@ -133,7 +141,9 @@ resultElement = getProcessedField(loadFieldNode.field()); } else if (node instanceof LoadIndexedNode) { LoadIndexedNode loadIndexedNode = (LoadIndexedNode) node; - resultElement = getProcessedArrayType(loadIndexedNode.array().stamp().declaredType()); + if (loadIndexedNode.kind() == Kind.Object) { + resultElement = getProcessedArrayType(metaAccessProvider.getResolvedJavaType(Object[].class)); + } } else if (node instanceof LocalNode) { LocalNode localNode = (LocalNode) node; if (localNode.kind() == Kind.Object) { @@ -240,7 +250,7 @@ } - public synchronized void printState() { + public synchronized int[] printState() { int nativeMethodCount = 0; for (MethodElement methodElement : methodMap.values()) { @@ -266,7 +276,9 @@ int fieldCount = 0; for (FieldElement fieldElement : fieldMap.values()) { if (fieldElement.getUsageCount() > 0) { - System.out.println("Included field: " + fieldElement.getJavaField()); + System.out.print("Included field: " + fieldElement.getJavaField() + " / "); + fieldElement.printSeenTypes(); + System.out.println(); fieldCount++; includedTypes.add(fieldElement.getJavaField().holder()); } @@ -280,5 +292,6 @@ System.out.println("Number of included method: " + methodCount); System.out.println("Number of included fields: " + fieldCount); System.out.println("Number of included types: " + includedTypes.size()); + return new int[]{nativeMethodCount, methodCount, fieldCount, includedTypes.size()}; } }
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/BootImageGenerator.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/BootImageGenerator.java Sat Jun 16 02:19:38 2012 +0200 @@ -54,9 +54,7 @@ bigbang.finish(); } - - public void printState() { - System.out.println("State of boot image generation"); - bigbang.printState(); + public BigBang getBigBang() { + return bigbang; } }
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/UniverseExpansionOp.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/UniverseExpansionOp.java Sat Jun 16 02:19:38 2012 +0200 @@ -22,9 +22,6 @@ */ package com.oracle.graal.boot; -import com.oracle.graal.boot.*; - - public abstract class UniverseExpansionOp implements Runnable {
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ArrayTypeElement.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ArrayTypeElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -22,7 +22,13 @@ */ package com.oracle.graal.boot.meta; +import java.util.*; + import com.oracle.graal.api.meta.*; +import com.oracle.graal.boot.*; +import com.oracle.graal.graph.*; +import com.oracle.graal.nodes.*; +import com.oracle.graal.nodes.java.*; public class ArrayTypeElement extends Element { @@ -36,6 +42,28 @@ @Override public String toString() { - return javaType + super.toString(); + return "arrayTypeElement: " + javaType; + } + + @Override + protected void propagateTypesToUsage(BigBang bb, Node use, Set<ResolvedJavaType> set, Element element) { + LoadIndexedNode load = (LoadIndexedNode) use; + ResolvedJavaType declaredType = load.array().stamp().declaredType(); + if (declaredType == null) { + System.out.println("FATAL error: Array access without declared type!"); + System.out.println(load.array()); + System.out.println(((StructuredGraph) load.graph()).method()); + System.exit(-1); + } + ResolvedJavaType componentType = declaredType.componentType(); + Set<ResolvedJavaType> newSet = new HashSet<>(); + for (ResolvedJavaType myType : set) { + if (myType.isSubtypeOf(componentType)) { + newSet.add(myType); + } + } + if (newSet.size() > 0) { + super.propagateTypesToUsage(bb, use, newSet, element); + } } }
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/CastElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -0,0 +1,61 @@ +/* + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package com.oracle.graal.boot.meta; + +import java.util.*; + +import com.oracle.graal.api.meta.*; +import com.oracle.graal.boot.*; +import com.oracle.graal.graph.*; +import com.oracle.graal.nodes.java.*; + + +public class CastElement extends Element { + + private CheckCastNode checkCastNode; + + public CastElement(CheckCastNode checkCastNode) { + super(checkCastNode.targetClass()); + this.checkCastNode = checkCastNode; + this.usages.add(checkCastNode); + } + + @Override + protected synchronized void unionTypes(BigBang bb, Node sourceNode, Set<ResolvedJavaType> newSeenTypes) { + Set<ResolvedJavaType> newSet = new HashSet<>(); + // Filter through checkcast. + for (ResolvedJavaType type : newSeenTypes) { + if (type.isSubtypeOf(checkCastNode.targetClass())) { + newSet.add(type); + } else { + System.out.println("filtering " + type + " vs " + checkCastNode.targetClass()); + } + } + super.unionTypes(bb, sourceNode, newSet); + } + + @Override + public String toString() { + return "cast " + checkCastNode.targetClass(); + } +}
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/Element.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/Element.java Sat Jun 16 02:19:38 2012 +0200 @@ -101,16 +101,27 @@ } } - public static void propagateTypes(BigBang bb, Node n, Set<ResolvedJavaType> types) { + public void propagateTypes(BigBang bb, Node n, Set<ResolvedJavaType> types) { if (types.size() != 0) { Set<ResolvedJavaType> newSet = new HashSet<>(types); for (Node use : n.usages()) { Element element = bb.getSinkElement(use, n); assert element != null; if (element != BLACK_HOLE) { - element.postUnionTypes(bb, n, newSet); + propagateTypesToUsage(bb, n, newSet, element); } } } } + + protected void propagateTypesToUsage(BigBang bb, Node use, Set<ResolvedJavaType> newSet, Element element) { + element.postUnionTypes(bb, use, newSet); + } + + + public synchronized void printSeenTypes() { + for (ResolvedJavaType type : seenTypes) { + System.out.print(type.name() + " "); + } + } }
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/InvokeElement.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/InvokeElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -47,7 +47,7 @@ @Override protected synchronized void unionTypes(BigBang bb, Node sourceNode, Set<ResolvedJavaType> newSeenTypes) { - System.out.println("union invoke element " + this); + System.out.println("union invoke element " + this + " new types = " + newSeenTypes + " sourceNode= " + sourceNode); int index = 0; for (Node arg : methodCallTarget.arguments()) { if (arg == sourceNode) { @@ -63,12 +63,22 @@ return "Invoke[bci=" + methodCallTarget.invoke().stateAfter().method() + "," + methodCallTarget.targetMethod() + "]"; } + public synchronized void expandStaticMethod(BigBang bb) { + if (methodCallTarget.isStatic()) { + ResolvedJavaMethod method = methodCallTarget.targetMethod(); + concreteTargets.add(method); + MethodElement processedMethod = bb.getProcessedMethod(method); + processedMethod.postParseGraph(bb); + } + } + private void unionTypes(BigBang bb, @SuppressWarnings("unused") Node sourceNode, Set<ResolvedJavaType> newSeenTypes, int index) { if (index == 0 && !methodCallTarget.isStatic()) { for (ResolvedJavaType type : newSeenTypes) { if (seenTypes.add(type)) { // There is a new receiver type! ResolvedJavaMethod method = type.resolveMethodImpl(methodCallTarget.targetMethod()); + System.out.println("resolved method " + method + " for type " + type + " and method " + methodCallTarget.targetMethod()); if (method == null) { System.out.println("!!! type = " + type + " / " + methodCallTarget.targetMethod()); }
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/MethodElement.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/MethodElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -28,6 +28,7 @@ import com.oracle.graal.api.meta.*; import com.oracle.graal.boot.*; import com.oracle.graal.compiler.*; +import com.oracle.graal.compiler.phases.*; import com.oracle.graal.graph.*; import com.oracle.graal.java.*; import com.oracle.graal.java.GraphBuilderConfiguration.*; @@ -79,13 +80,17 @@ }.post(bb); } - protected synchronized void parseGraph(final BigBang bb) { - if (graph != null) { - // Graph already exists => quit operation. - return; + protected void parseGraph(final BigBang bb) { + StructuredGraph newGraph = null; + synchronized (this) { + if (graph != null) { + // Graph already exists => quit operation. + return; + } + newGraph = new StructuredGraph(resolvedJavaMethod); + this.graph = newGraph; } - StructuredGraph newGraph = new StructuredGraph(resolvedJavaMethod); - this.graph = newGraph; + if (Modifier.isNative(resolvedJavaMethod.accessFlags())) { System.out.println("NATIVE METHOD " + resolvedJavaMethod); return; @@ -95,6 +100,8 @@ GraphBuilderConfiguration config = new GraphBuilderConfiguration(ResolvePolicy.Eager, null); GraphBuilderPhase graphBuilderPhase = new GraphBuilderPhase(bb.getMetaAccess(), config, OptimisticOptimizations.NONE); graphBuilderPhase.apply(newGraph); + new PhiStampPhase().apply(newGraph); + for (MethodCallTargetNode callTargetNode : newGraph.getNodes(MethodCallTargetNode.class)) { bb.registerSourceCallTargetNode(callTargetNode); } @@ -107,7 +114,13 @@ Set<ResolvedJavaType> types = new HashSet<>(); types.add(newInstance.instanceClass()); System.out.println("propagate new instance " + newInstance + ", " + newInstance.instanceClass()); - Element.propagateTypes(bb, newInstance, types); + for (Node use : newInstance.usages()) { + Element element = bb.getSinkElement(use, newInstance); + assert element != null; + if (element != BLACK_HOLE) { + element.postUnionTypes(bb, newInstance, types); + } + } } }
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/PhiElement.java Sat Jun 16 02:17:44 2012 +0200 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/PhiElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -32,10 +32,11 @@ public PhiElement(PhiNode phi) { super(null); this.phi = phi; + usages.add(phi); } @Override public String toString() { - return "phi " + phi + super.toString(); + return "phi " + phi; } }
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ProxyElement.java Sat Jun 16 02:19:38 2012 +0200 @@ -0,0 +1,42 @@ +/* + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package com.oracle.graal.boot.meta; + +import com.oracle.graal.nodes.*; + + +public class ProxyElement extends Element { + + private ValueProxyNode proxy; + + public ProxyElement(ValueProxyNode proxy) { + super(null); + this.proxy = proxy; + usages.add(proxy); + } + + @Override + public String toString() { + return "value proxy " + proxy; + } +}