| /* |
| * Copyright (c) 2015, 2015, 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 org.graalvm.compiler.lir.alloc.lsra.ssa; |
| |
| import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue; |
| import static jdk.vm.ci.code.ValueUtil.isRegister; |
| |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.debug.Debug; |
| import org.graalvm.compiler.debug.Indent; |
| import org.graalvm.compiler.lir.LIRInstruction; |
| import org.graalvm.compiler.lir.StandardOp.LabelOp; |
| import org.graalvm.compiler.lir.StandardOp.MoveOp; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval; |
| import org.graalvm.compiler.lir.alloc.lsra.LinearScan; |
| import org.graalvm.compiler.lir.alloc.lsra.LinearScanEliminateSpillMovePhase; |
| |
| public class SSALinearScanEliminateSpillMovePhase extends LinearScanEliminateSpillMovePhase { |
| |
| SSALinearScanEliminateSpillMovePhase(LinearScan allocator) { |
| super(allocator); |
| } |
| |
| @Override |
| protected int firstInstructionOfInterest() { |
| // also look at Labels as they define PHI values |
| return 0; |
| } |
| |
| @Override |
| protected boolean canEliminateSpillMove(AbstractBlockBase<?> block, MoveOp move) { |
| if (super.canEliminateSpillMove(block, move)) { |
| // SSA Linear Scan might introduce moves to stack slots |
| Interval curInterval = allocator.intervalFor(move.getResult()); |
| assert !isRegister(curInterval.location()) && curInterval.alwaysInMemory(); |
| if (!isPhiResolutionMove(block, move, curInterval)) { |
| assert isStackSlotValue(curInterval.location()) : "Not a stack slot: " + curInterval.location(); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @SuppressWarnings("try") |
| private boolean isPhiResolutionMove(AbstractBlockBase<?> block, MoveOp move, Interval toInterval) { |
| if (!toInterval.isSplitParent()) { |
| return false; |
| } |
| if ((toInterval.from() & 1) == 1) { |
| // phi intervals start at even positions. |
| return false; |
| } |
| if (block.getSuccessorCount() != 1) { |
| return false; |
| } |
| LIRInstruction op = allocator.instructionForId(toInterval.from()); |
| if (!(op instanceof LabelOp)) { |
| return false; |
| } |
| AbstractBlockBase<?> intStartBlock = allocator.blockForId(toInterval.from()); |
| assert allocator.getLIR().getLIRforBlock(intStartBlock).get(0).equals(op); |
| if (!block.getSuccessors()[0].equals(intStartBlock)) { |
| return false; |
| } |
| try (Indent indet = Debug.indent()) { |
| Debug.log("Is a move (%s) to phi interval %s", move, toInterval); |
| } |
| return true; |
| } |
| } |