# HG changeset patch
# User Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
# Date 1358377587 -3600
# Node ID 741ceb12ff7d6a45d2cff73b76f640049db96a4b
# Parent  921bde171d1d601d4d413a175432c977078d32ef
Implement basic lock elimination phase.

diff -r 921bde171d1d -r 741ceb12ff7d graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Wed Jan 16 16:17:07 2013 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Thu Jan 17 00:06:27 2013 +0100
@@ -149,6 +149,9 @@
         if (GraalOptions.PartialEscapeAnalysis && !plan.isPhaseDisabled(PartialEscapeAnalysisPhase.class)) {
             new PartialEscapeAnalysisPhase(target, runtime, assumptions, true).apply(graph);
         }
+
+        new LockEliminationPhase().apply(graph);
+
         if (GraalOptions.OptLoopTransform) {
             new LoopTransformHighPhase().apply(graph);
             new LoopTransformLowPhase().apply(graph);
diff -r 921bde171d1d -r 741ceb12ff7d graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/LockEliminationPhase.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/LockEliminationPhase.java	Thu Jan 17 00:06:27 2013 +0100
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 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.phases.common;
+
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.java.*;
+import com.oracle.graal.nodes.util.*;
+import com.oracle.graal.phases.*;
+
+
+public class LockEliminationPhase extends Phase {
+
+    @Override
+    protected void run(StructuredGraph graph) {
+        for (MonitorExitNode node : graph.getNodes(MonitorExitNode.class)) {
+            FixedNode next = node.next();
+            if (next instanceof MonitorEnterNode) {
+                MonitorEnterNode monitorEnterNode = (MonitorEnterNode) next;
+                if (monitorEnterNode.object() == node.object()) {
+                    ((FixedWithNextNode) node.predecessor()).setNext(monitorEnterNode.next());
+                    FrameState stateAfterFirst = node.stateAfter();
+                    FrameState stateAfterSecond = monitorEnterNode.stateAfter();
+                    node.safeDelete();
+                    monitorEnterNode.safeDelete();
+                    if (stateAfterFirst.usages().isEmpty()) {
+                        GraphUtil.killWithUnusedFloatingInputs(stateAfterFirst);
+                    }
+                    if (stateAfterSecond.usages().isEmpty()) {
+                        GraphUtil.killWithUnusedFloatingInputs(stateAfterSecond);
+                    }
+                }
+            }
+        }
+    }
+}