# HG changeset patch
# User Doug Simon <doug.simon@oracle.com>
# Date 1340371183 -7200
# Node ID 0ca242de93836392bcdf61ed85cc2fad62febf6f
# Parent  f787843c890ca0b62325052f06dcc3f7b96d4040
improved type stamp for value flowing out of a lowered NEW bytecode instruction
removed declaredType() and exactType() from Stamp

diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ArrayTypeElement.java
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ArrayTypeElement.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/ArrayTypeElement.java	Fri Jun 22 15:19:43 2012 +0200
@@ -48,14 +48,14 @@
     @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!");
+        ResolvedJavaType type = load.array().objectStamp().type();
+        if (type == null) {
+            System.out.println("FATAL error: Array access without type!");
             System.out.println(load.array());
             System.out.println(((StructuredGraph) load.graph()).method());
             System.exit(-1);
         }
-        ResolvedJavaType componentType = declaredType.componentType();
+        ResolvedJavaType componentType = type.componentType();
         Set<ResolvedJavaType> newSet = new HashSet<>();
         for (ResolvedJavaType myType : set) {
             if (myType.isSubtypeOf(componentType)) {
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/InvokeElement.java
--- a/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/InvokeElement.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.boot/src/com/oracle/graal/boot/meta/InvokeElement.java	Fri Jun 22 15:19:43 2012 +0200
@@ -51,7 +51,7 @@
         int index = 0;
         for (Node arg : methodCallTarget.arguments()) {
             if (arg == sourceNode) {
-                System.out.println("source node " + sourceNode + " is at index " + index + " declaredType=" + ((ValueNode) sourceNode).stamp().declaredType());
+                System.out.println("source node " + sourceNode + " is at index " + index + " stamp=" + ((ValueNode) sourceNode).stamp());
                 unionTypes(bb, sourceNode, newSeenTypes, index);
             }
             ++index;
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/CastFromHub.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/CastFromHub.java	Fri Jun 22 15:19:43 2012 +0200
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2009, 2011, 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.hotspot.nodes;
+
+import com.oracle.graal.api.meta.*;
+import com.oracle.graal.hotspot.*;
+import com.oracle.graal.hotspot.snippets.*;
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.calc.*;
+import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.spi.*;
+import com.oracle.graal.nodes.type.*;
+
+/**
+ * This node is used by the {@link NewInstanceSnippets} to give a formatted new instance its exact type.
+ */
+public final class CastFromHub extends FloatingNode implements Canonicalizable {
+
+    @Input private ValueNode object;
+    @Input private ValueNode hub;
+
+    public ValueNode object() {
+        return object;
+    }
+
+    public CastFromHub(ValueNode object, ValueNode hubObject) {
+        // TODO: the non-nullness should really be derived from 'object' but until
+        // control flow sensitive type analysis is implemented, the object coming
+        // from the TLAB fast path is not non-null
+        super(StampFactory.objectNonNull());
+        this.object = object;
+        this.hub = hubObject;
+    }
+
+    @Override
+    public ValueNode canonical(CanonicalizerTool tool) {
+        if (hub.isConstant()) {
+            ResolvedJavaType type = ((HotSpotKlassOop) this.hub.asConstant().asObject()).type;
+            return graph().unique(new UnsafeCastNode(object, type, true, true));
+        }
+        return this;
+    }
+
+    @SuppressWarnings("unused")
+    @NodeIntrinsic
+    public static <T> T castFromHub(Object object, Object hub) {
+        throw new UnsupportedOperationException("This method may only be compiled with the Graal compiler");
+    }
+}
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/snippets/NewInstanceSnippets.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/snippets/NewInstanceSnippets.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/snippets/NewInstanceSnippets.java	Fri Jun 22 15:19:43 2012 +0200
@@ -22,6 +22,7 @@
  */
 package com.oracle.graal.hotspot.snippets;
 
+import static com.oracle.graal.hotspot.nodes.CastFromHub.*;
 import static com.oracle.graal.hotspot.nodes.RegisterNode.*;
 import static com.oracle.graal.hotspot.snippets.DirectObjectStoreNode.*;
 import static com.oracle.graal.nodes.extended.UnsafeLoadNode.*;
@@ -74,9 +75,9 @@
         if (memory == Word.zero()) {
             return NewInstanceStubCall.call(hub);
         }
+        formatObject(hub, size, memory);
         Object instance = memory.toObject();
-        formatInstance(hub, size, instance);
-        return verifyOop(instance);
+        return castFromHub(verifyOop(instance), hub);
     }
 
     private static Object verifyOop(Object object) {
@@ -101,15 +102,15 @@
     }
 
     /**
-     * Formats the header of a created instance and zeroes out its body.
+     * Formats some allocated memory with an object header zeroes out the rest.
      */
-    private static void formatInstance(Object hub, int size, Object instance) {
+    private static void formatObject(Object hub, int size, Word memory) {
         Word headerPrototype = loadWord(hub, instanceHeaderPrototypeOffset());
-        store(instance, 0, 0, headerPrototype);
-        store(instance, 0, hubOffset(), hub);
+        store(memory, 0, 0, headerPrototype);
+        store(memory, 0, hubOffset(), hub);
         explodeLoop();
         for (int offset = 2 * wordSize(); offset < size; offset += wordSize()) {
-            store(instance, 0, offset, 0);
+            store(memory, 0, offset, 0);
         }
     }
 
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java	Fri Jun 22 15:19:43 2012 +0200
@@ -23,7 +23,6 @@
 package com.oracle.graal.nodes.extended;
 
 import com.oracle.graal.api.meta.*;
-import com.oracle.graal.cri.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.spi.*;
@@ -32,7 +31,7 @@
 /**
  * The {@code UnsafeCastNode} produces the same value as its input, but with a different type.
  */
-public final class UnsafeCastNode extends FloatingNode implements Canonicalizable, Lowerable, LIRLowerable {
+public final class UnsafeCastNode extends FloatingNode implements Canonicalizable, LIRLowerable {
 
     @Input private ValueNode object;
     private ResolvedJavaType toType;
@@ -41,6 +40,12 @@
         return object;
     }
 
+    public UnsafeCastNode(ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
+        super(toType.kind().isObject() ? new ObjectStamp(toType, exactType, nonNull) : StampFactory.forKind(toType.kind()));
+        this.object = object;
+        this.toType = toType;
+    }
+
     public UnsafeCastNode(ValueNode object, ResolvedJavaType toType) {
         super(toType.kind().isObject() ? StampFactory.declared(toType, object.stamp().nonNull()) : StampFactory.forKind(toType.kind()));
         this.object = object;
@@ -49,20 +54,35 @@
 
     @Override
     public ValueNode canonical(CanonicalizerTool tool) {
-        if (object != null && object.kind().isObject() && object.objectStamp().type() != null && object.objectStamp().type().isSubtypeOf(toType)) {
-            return object;
+        if (object != null) {
+            if (object.kind().isObject()) {
+                if (object.objectStamp().type() != null && object.objectStamp().type().isSubtypeOf(toType)) {
+                    if (!isNarrower(objectStamp(), object.objectStamp())) {
+                        return object;
+                    }
+                }
+            } else if (object.kind() == kind()) {
+                // Removes redundant casts introduced by WordTypeRewriterPhase
+                return object;
+            }
         }
         return this;
     }
 
-
-    @Override
-    public void lower(CiLoweringTool tool) {
-        if (object.kind() == kind()) {
-            ((StructuredGraph) graph()).replaceFloating(this, object);
-        } else {
-            // Cannot remove an unsafe cast between two different kinds
+    /**
+     * Determines if one object stamp is narrower than another in terms of nullness and exactness.
+     *
+     * @return true if x is definitely non-null and y's nullness is unknown OR
+     *                  x's type is exact and the exactness of y's type is unknown
+     */
+    private static boolean isNarrower(ObjectStamp x, ObjectStamp y) {
+        if (x.nonNull() && !y.nonNull()) {
+            return true;
         }
+        if (x.isExactType() && !y.isExactType()) {
+            return true;
+        }
+        return false;
     }
 
     @SuppressWarnings("unused")
@@ -71,6 +91,12 @@
         throw new UnsupportedOperationException("This method may only be compiled with the Graal compiler");
     }
 
+    @SuppressWarnings("unused")
+    @NodeIntrinsic
+    public static <T> T cast(Object object, @ConstantNodeParameter Class<?> toType, @ConstantNodeParameter boolean exactType, @ConstantNodeParameter boolean nonNull) {
+        throw new UnsupportedOperationException("This method may only be compiled with the Graal compiler");
+    }
+
     @Override
     public void generate(LIRGeneratorTool generator) {
         Value result = generator.newVariable(kind());
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java	Fri Jun 22 15:19:43 2012 +0200
@@ -53,16 +53,6 @@
     }
 
     @Override
-    public ResolvedJavaType exactType() {
-        return exactType ? type : null;
-    }
-
-    @Override
-    public ResolvedJavaType declaredType() {
-        return type;
-    }
-
-    @Override
     public String toString() {
         StringBuilder str = new StringBuilder();
         str.append(kind().typeChar);
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/Stamp.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/Stamp.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/Stamp.java	Fri Jun 22 15:19:43 2012 +0200
@@ -25,7 +25,9 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.nodes.spi.types.*;
 
-
+/**
+ * A stamp is the basis for a type system over the nodes in a graph.
+ */
 public abstract class Stamp {
 
     private final Kind kind;
@@ -50,14 +52,6 @@
         return false;
     }
 
-    public ResolvedJavaType exactType() {
-        return null;
-    }
-
-    public ResolvedJavaType declaredType() {
-        return null;
-    }
-
     public abstract boolean alwaysDistinct(Stamp other);
 
     public abstract Stamp meet(Stamp other);
diff -r f787843c890c -r 0ca242de9383 graal/com.oracle.graal.snippets/src/com/oracle/graal/snippets/WordTypeRewriterPhase.java
--- a/graal/com.oracle.graal.snippets/src/com/oracle/graal/snippets/WordTypeRewriterPhase.java	Fri Jun 22 10:43:06 2012 +0200
+++ b/graal/com.oracle.graal.snippets/src/com/oracle/graal/snippets/WordTypeRewriterPhase.java	Fri Jun 22 15:19:43 2012 +0200
@@ -236,7 +236,10 @@
     }
 
     public static boolean isWord(ValueNode node) {
-        return isWord(node.stamp().declaredType());
+        if (node.kind().isObject()) {
+            return isWord(node.objectStamp().type());
+        }
+        return false;
     }
 
     public static boolean isWord(ResolvedJavaType type) {