Mercurial > hg > graal-jvmci-8
diff graal/Compiler/src/com/sun/c1x/ir/Phi.java @ 2507:9ec15d6914ca
Pull over of compiler from maxine repository.
author | Thomas Wuerthinger <thomas@wuerthinger.net> |
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date | Wed, 27 Apr 2011 11:43:22 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/Compiler/src/com/sun/c1x/ir/Phi.java Wed Apr 27 11:43:22 2011 +0200 @@ -0,0 +1,153 @@ +/* + * 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.value.*; +import com.sun.cri.ci.*; + +/** + * The {@code Phi} instruction represents the merging of dataflow + * in the instruction graph. It refers to a join block and a variable. + * + * @author Ben L. Titzer + */ +public final class Phi extends Value { + + private final BlockBegin block; + private final int index; + + /** + * Create a new Phi for the specified join block and local variable (or operand stack) slot. + * @param kind the type of the variable + * @param block the join point + * @param index the index into the stack (if < 0) or local variables + */ + public Phi(CiKind kind, BlockBegin block, int index) { + super(kind); + this.block = block; + this.index = index; + } + + /** + * Get the join block for this phi. + * @return the join block of this phi + */ + @Override + public BlockBegin block() { + return block; + } + + /** + * Check whether this phi corresponds to a local variable. + * @return {@code true} if this phi refers to a local variable + */ + public boolean isLocal() { + return index >= 0; + } + + /** + * Check whether this phi corresponds to a stack location. + * @return {@code true} if this phi refers to a stack location + */ + public boolean isOnStack() { + return index < 0; + } + + /** + * Get the local index of this phi. + * @return the local index + */ + public int localIndex() { + assert isLocal(); + return index; + } + + /** + * Get the stack index of this phi. + * @return the stack index of this phi + */ + public int stackIndex() { + assert isOnStack(); + return -(index + 1); + } + + /** + * Get the instruction that produces the value associated with the i'th predecessor + * of the join block. + * @param i the index of the predecessor + * @return the instruction that produced the value in the i'th predecessor + */ + public Value inputAt(int i) { + FrameState state; + if (block.isExceptionEntry()) { + state = block.exceptionHandlerStates().get(i); + } else { + state = block.predecessors().get(i).end().stateAfter(); + } + return inputIn(state); + } + + /** + * Gets the instruction that produces the value for this phi in the specified state. + * @param state the state to access + * @return the instruction producing the value + */ + public Value inputIn(FrameState state) { + if (isLocal()) { + return state.localAt(localIndex()); + } else { + return state.stackAt(stackIndex()); + } + } + + /** + * Get the number of inputs to this phi (i.e. the number of predecessors to the join block). + * @return the number of inputs in this phi + */ + public int inputCount() { + if (block.isExceptionEntry()) { + return block.exceptionHandlerStates().size(); + } else { + return block.predecessors().size(); + } + } + + @Override + public void accept(ValueVisitor v) { + v.visitPhi(this); + } + + /** + * Make this phi illegal if types were not merged correctly. + */ + public void makeDead() { + setFlag(Flag.PhiCannotSimplify); + setFlag(Flag.PhiDead); + } + + @Override + public void print(LogStream out) { + out.print("phi function"); + } +}