/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Eclipse Public License (EPL);
* 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/eclipse-1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.jikesrvm.compilers.opt.controlflow;
import org.jikesrvm.compilers.opt.driver.CompilerPhase;
import org.jikesrvm.compilers.opt.ir.IR;
/**
* A compiler phase to construct the loop structure tree (LST).
* The steps are (1) construct approximate dominators (ie blocks are
* not unfactored) and (2) build the LST.
*
* @see LTDominators
* @see LSTGraph
*/
public class BuildLST extends CompilerPhase {
@Override
public String getName() {
return "Build LST";
}
/**
* This phase contains no per-compilation instance fields.
*/
@Override
public final CompilerPhase newExecution(IR ir) {
return this;
}
/**
* Build the Loop Structure Tree (LST) for the given IR.
* NOTE: CFG must be reducible.
* TODO: Detect irreducible CFG, apply node splitting and then construct LST.
*
* @param ir the IR on which to apply the phase
*/
@Override
public void perform(IR ir) {
ir.cfg.compactNodeNumbering();
LTDominators.approximate(ir, true);
DominatorTree.perform(ir, true);
LSTGraph.perform(ir);
}
}