1 /* 2 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.lir.alloc.trace; 24 25 import java.util.List; 26 27 import org.graalvm.compiler.core.common.alloc.Trace; 28 import org.graalvm.compiler.core.common.alloc.TraceBuilderResult; 29 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; 30 import org.graalvm.compiler.lir.LIR; 31 import org.graalvm.compiler.lir.LIRInstruction; 32 import org.graalvm.compiler.lir.StandardOp.JumpOp; 33 import org.graalvm.compiler.lir.StandardOp.LabelOp; 34 35 import jdk.vm.ci.meta.Value; 36 37 public class TraceUtil { 38 39 public static AbstractBlockBase<?> getBestTraceInterPredecessor(TraceBuilderResult traceResult, AbstractBlockBase<?> block) { 40 AbstractBlockBase<?> bestPred = null; 41 int bestTraceId = traceResult.getTraceForBlock(block).getId(); 42 for (AbstractBlockBase<?> pred : block.getPredecessors()) { 43 int predTraceId = traceResult.getTraceForBlock(pred).getId(); 44 if (predTraceId < bestTraceId) { 45 bestPred = pred; 46 bestTraceId = predTraceId; 47 } 48 } 49 return bestPred; 50 } 51 52 public static boolean isShadowedRegisterValue(Value value) { 53 assert value != null; 54 return value instanceof ShadowedRegisterValue; 55 } 56 57 public static ShadowedRegisterValue asShadowedRegisterValue(Value value) { 58 assert isShadowedRegisterValue(value); 59 return (ShadowedRegisterValue) value; 60 } 61 62 public static boolean isTrivialTrace(LIR lir, Trace trace) { 63 if (trace.size() != 1) { 64 return false; 65 } 66 List<LIRInstruction> instructions = lir.getLIRforBlock(trace.getBlocks()[0]); 67 if (instructions.size() != 2) { 68 return false; 69 } 70 assert instructions.get(0) instanceof LabelOp : "First instruction not a LabelOp: " + instructions.get(0); 71 if (((LabelOp) instructions.get(0)).isPhiIn()) { 72 /* 73 * Merge blocks are in general not trivial block because variables defined by a PHI 74 * always need a location. If the outgoing value of the predecessor is a constant we 75 * need to find an appropriate location (register or stack). 76 * 77 * Note that this case should not happen in practice since the trace containing the 78 * merge block should also contain one of the predecessors. For non-standard trace 79 * builders (e.g. the single block trace builder) this is not the true, though. 80 */ 81 return false; 82 } 83 /* 84 * Now we need to check if the BlockEndOp has no special operand requirements (i.e. 85 * stack-slot, register). For now we just check for JumpOp because we know that it doesn't. 86 */ 87 return instructions.get(1) instanceof JumpOp; 88 } 89 }