/* * 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.regalloc; import java.util.Enumeration; import org.jikesrvm.compilers.opt.ir.BasicBlock; import org.jikesrvm.compilers.opt.ir.IR; import org.jikesrvm.compilers.opt.ir.Instruction; import org.jikesrvm.compilers.opt.ir.Register; import org.jikesrvm.compilers.opt.ir.operand.MemoryOperand; import org.jikesrvm.compilers.opt.ir.operand.Operand; /** * An object that returns an estimate of the relative cost of spilling a * symbolic register, based on basic block frequencies. */ final class BlockCountSpillCost extends SpillCostEstimator { BlockCountSpillCost(IR ir) { calculate(ir); } @Override void calculate(IR ir) { final double moveFactor = ir.options.REGALLOC_SIMPLE_SPILL_COST_MOVE_FACTOR; final double memoryOperandFactor = ir.options.REGALLOC_SIMPLE_SPILL_COST_MEMORY_OPERAND_FACTOR; for (Enumeration<BasicBlock> blocks = ir.getBasicBlocks(); blocks.hasMoreElements();) { BasicBlock bb = blocks.nextElement(); float freq = bb.getExecutionFrequency(); for (Enumeration<Instruction> e = bb.forwardInstrEnumerator(); e.hasMoreElements();) { Instruction s = e.nextElement(); double factor = freq; if (s.isMove()) factor *= moveFactor; double baseFactor = factor; if (SimpleSpillCost.hasBadSizeMemoryOperand(s)) { baseFactor *= memoryOperandFactor; } // first deal with non-memory operands for (Enumeration<Operand> e2 = s.getRootOperands(); e2.hasMoreElements();) { Operand op = e2.nextElement(); if (op.isRegister()) { Register r = op.asRegister().getRegister(); if (r.isSymbolic()) { update(r, baseFactor); } } } // now handle memory operands factor *= memoryOperandFactor; for (Enumeration<Operand> e2 = s.getMemoryOperands(); e2.hasMoreElements();) { MemoryOperand M = (MemoryOperand) e2.nextElement(); if (M.base != null) { Register r = M.base.getRegister(); if (r.isSymbolic()) { update(r, factor); } } if (M.index != null) { Register r = M.index.getRegister(); if (r.isSymbolic()) { update(r, factor); } } } } } } }