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 

    24 

    25 package org.graalvm.compiler.lir.alloc.trace;

    26 

    27 import java.util.ArrayList;

    28 

    29 import org.graalvm.compiler.core.common.alloc.Trace;

    30 import org.graalvm.compiler.core.common.alloc.TraceBuilderResult;

    31 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;

    32 import org.graalvm.compiler.lir.LIR;

    33 import org.graalvm.compiler.lir.LIRInstruction;

    34 import org.graalvm.compiler.lir.StandardOp.JumpOp;

    35 import org.graalvm.compiler.lir.StandardOp.LabelOp;

    36 

    37 import jdk.vm.ci.meta.Value;

    38 

    39 public class TraceUtil {

    40 

    41     public static boolean isShadowedRegisterValue(Value value) {

    42         assert value != null;

    43         return value instanceof ShadowedRegisterValue;

    44     }

    45 

    46     public static ShadowedRegisterValue asShadowedRegisterValue(Value value) {

    47         assert isShadowedRegisterValue(value);

    48         return (ShadowedRegisterValue) value;

    49     }

    50 

    51     public static boolean isTrivialTrace(LIR lir, Trace trace) {

    52         if (trace.size() != 1) {

    53             return false;

    54         }

    55         ArrayList<LIRInstruction> instructions = lir.getLIRforBlock(trace.getBlocks()[0]);

    56         if (instructions.size() != 2) {

    57             return false;

    58         }

    59         assert instructions.get(0) instanceof LabelOp : "First instruction not a LabelOp: " + instructions.get(0);

    60         if (((LabelOp) instructions.get(0)).isPhiIn()) {

    61             /*

    62              * Merge blocks are in general not trivial block because variables defined by a PHI

    63              * always need a location. If the outgoing value of the predecessor is a constant we

    64              * need to find an appropriate location (register or stack).

    65              *

    66              * Note that this case should not happen in practice since the trace containing the

    67              * merge block should also contain one of the predecessors. For non-standard trace

    68              * builders (e.g. the single block trace builder) this is not the true, though.

    69              */

    70             return false;

    71         }

    72         /*

    73          * Now we need to check if the BlockEndOp has no special operand requirements (i.e.

    74          * stack-slot, register). For now we just check for JumpOp because we know that it doesn't.

    75          */

    76         return instructions.get(1) instanceof JumpOp;

    77     }

    78 

    79     public static boolean hasInterTracePredecessor(TraceBuilderResult result, Trace trace, AbstractBlockBase<?> block) {

    80         assert result.getTraceForBlock(block).equals(trace);

    81         if (block.getPredecessorCount() == 0) {

    82             // start block

    83             return false;

    84         }

    85         if (block.getPredecessorCount() == 1) {

    86             return !result.getTraceForBlock(block.getPredecessors()[0]).equals(trace);

    87         }

    88         return true;

    89     }

    90 

    91     public static boolean hasInterTraceSuccessor(TraceBuilderResult result, Trace trace, AbstractBlockBase<?> block) {

    92         assert result.getTraceForBlock(block).equals(trace);

    93         if (block.getSuccessorCount() == 0) {

    94             // method end block

    95             return false;

    96         }

    97         if (block.getSuccessorCount() == 1) {

    98             return !result.getTraceForBlock(block.getSuccessors()[0]).equals(trace);

    99         }

   100         return true;

   101     }

   102 }