/*
* Copyright (c) 2010, 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
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*/
package com.sun.c1x.opt;
import com.sun.c1x.graph.*;
import com.sun.c1x.ir.*;
import com.sun.c1x.value.*;
/**
* A mechanism to remove {@linkplain UnsafeCast#redundant redundant} unsafe casts.
*/
public class UnsafeCastEliminator implements ValueClosure, BlockClosure {
final IR ir;
/**
* Eliminates redundant unsafe casts from a given IR.
*/
public UnsafeCastEliminator(IR ir) {
this.ir = ir;
ir.startBlock.iterateAnyOrder(this, false);
}
public void apply(BlockBegin block) {
if (block.isExceptionEntry()) {
for (FrameState ehState : block.exceptionHandlerStates()) {
ehState.valuesDo(this);
}
}
Instruction i = block;
while (i != null) {
FrameState stateBefore = i.stateBefore();
if (stateBefore != null) {
stateBefore.valuesDo(this);
}
i.inputValuesDo(this);
FrameState stateAfter = i.stateAfter();
if (stateAfter != null) {
stateAfter.valuesDo(this);
}
i = i.next();
}
}
public Value apply(Value i) {
if (i instanceof UnsafeCast) {
Value y = ((UnsafeCast) i).nonRedundantReplacement();
assert y != null;
return y;
}
return i;
}
}