Mercurial > hg > graal-compiler
view graal/GraalCompiler/src/com/sun/c1x/ir/Phi.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/Phi.java@9ec15d6914ca |
children | 4a36a0bd6d18 |
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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.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"); } }