| /* |
| * Copyright (c) 2013, 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; |
| |
| import java.util.List; |
| |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.lir.StandardOp.ImplicitNullCheck; |
| import org.graalvm.compiler.lir.StandardOp.NullCheck; |
| import org.graalvm.compiler.lir.gen.LIRGenerationResult; |
| import org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase; |
| |
| import jdk.vm.ci.code.TargetDescription; |
| |
| public final class NullCheckOptimizer extends PostAllocationOptimizationPhase { |
| |
| @Override |
| protected void run(TargetDescription target, LIRGenerationResult lirGenRes, PostAllocationOptimizationContext context) { |
| LIR ir = lirGenRes.getLIR(); |
| AbstractBlockBase<?>[] blocks = ir.codeEmittingOrder(); |
| NullCheckOptimizer.foldNullChecks(ir, blocks, target.implicitNullCheckLimit); |
| } |
| |
| private static void foldNullChecks(LIR ir, AbstractBlockBase<?>[] blocks, int implicitNullCheckLimit) { |
| for (AbstractBlockBase<?> block : blocks) { |
| if (block == null) { |
| continue; |
| } |
| List<LIRInstruction> list = ir.getLIRforBlock(block); |
| |
| if (!list.isEmpty()) { |
| |
| LIRInstruction lastInstruction = list.get(0); |
| for (int i = 0; i < list.size(); i++) { |
| LIRInstruction instruction = list.get(i); |
| |
| if (instruction instanceof ImplicitNullCheck && lastInstruction instanceof NullCheck) { |
| NullCheck nullCheck = (NullCheck) lastInstruction; |
| ImplicitNullCheck implicitNullCheck = (ImplicitNullCheck) instruction; |
| if (implicitNullCheck.makeNullCheckFor(nullCheck.getCheckedValue(), nullCheck.getState(), implicitNullCheckLimit)) { |
| list.remove(i - 1); |
| if (i < list.size()) { |
| instruction = list.get(i); |
| } |
| } |
| } |
| lastInstruction = instruction; |
| } |
| } |
| } |
| } |
| |
| } |