Mercurial > hg > truffle
view graal/GraalCompiler/src/com/sun/c1x/ir/NullCheck.java @ 2509:16b9a8b5ad39
Renamings Runtime=>GraalRuntime and Compiler=>GraalCompiler
author | Thomas Wuerthinger <thomas@wuerthinger.net> |
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date | Wed, 27 Apr 2011 11:50:44 +0200 |
parents | graal/Compiler/src/com/sun/c1x/ir/NullCheck.java@9ec15d6914ca |
children | 0f9eeb15e636 |
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/* * 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.sun.c1x.ir; import com.sun.c1x.debug.*; import com.sun.c1x.util.*; import com.sun.c1x.value.*; import com.sun.cri.bytecode.*; import com.sun.cri.ri.*; /** * The {@code NullCheck} class represents an explicit null check instruction. * * @author Ben L. Titzer */ public final class NullCheck extends StateSplit { Value object; /** * Constructs a new NullCheck instruction. * @param obj the instruction producing the object to check against null * @param stateBefore the state before executing the null check */ public NullCheck(Value obj, FrameState stateBefore) { super(obj.kind, stateBefore); this.object = obj; setFlag(Flag.NonNull); if (object.isNonNull()) { eliminateNullCheck(); } } /** * Gets the instruction that produces the object tested against null. * @return the instruction producing the object */ public Value object() { return object; } /** * Checks whether this instruction can cause a trap. * @return {@code true} if this instruction can cause a trap */ @Override public boolean canTrap() { return needsNullCheck(); } @Override public void inputValuesDo(ValueClosure closure) { object = closure.apply(object); } @Override public void accept(ValueVisitor v) { v.visitNullCheck(this); } @Override public int valueNumber() { return Util.hash1(Bytecodes.IFNONNULL, object); } @Override public boolean valueEqual(Instruction i) { if (i instanceof NullCheck) { NullCheck o = (NullCheck) i; return object == o.object; } return false; } @Override public RiType declaredType() { // null check does not alter the type of the object return object.declaredType(); } @Override public RiType exactType() { // null check does not alter the type of the object return object.exactType(); } @Override public void runtimeCheckCleared() { clearState(); } @Override public void print(LogStream out) { out.print("null_check(").print(object()).print(')'); if (!canTrap()) { out.print(" (eliminated)"); } } }