/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Common Public License (CPL);
* You may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.opensource.org/licenses/cpl1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.jikesrvm.compilers.opt;
import org.jikesrvm.compilers.opt.ir.OPT_BasicBlock;
/**
* OPT_DominatorInfo.java
*
* This structure holds dominator-related information for a basic block.
*/
class OPT_DominatorInfo {
/**
* A BitVector which represents the dominators of the basic block
*/
OPT_BitVector dominators;
/**
* The basic block's immediate dominator.
*/
OPT_BasicBlock idom;
/**
* Make a structure with a given bit set holding the dominators
* of the basic block.
*
* @param dominators the bit set
*/
OPT_DominatorInfo(OPT_BitVector dominators) {
this.dominators = dominators;
}
/**
* Return the immediate dominator of a basic block.
*
* <p> Note: the dominator info must be calculated before calling this
* routine
*
* @param bb the basic block in question
* @return bb's immediate dominator, as cached in bb's DominatorInfo
*/
public static OPT_BasicBlock idom(OPT_BasicBlock bb) {
OPT_DominatorInfo info = (OPT_DominatorInfo) bb.scratchObject;
return info.idom;
}
/**
* Is the basic block represented by this structure dominated by another
* basic block?
*
* @param bb the basic block in question
* @return true or false
*/
boolean isDominatedBy(OPT_BasicBlock bb) {
return dominators.get(bb.getNumber());
}
/**
* Is one basic block (the slave) dominated by another (the master)?
*
* @param slave the potential dominatee
* @param master the potential dominator
* @return true or false
*/
static boolean isDominatedBy(OPT_BasicBlock slave, OPT_BasicBlock master) {
return ((OPT_DominatorInfo) slave.scratchObject).
dominators.get(master.getNumber());
}
}