1 /*
   2  * Copyright (c) 2009, 2018, 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;
  26 
  27 import java.util.ArrayList;
  28 import java.util.Arrays;
  29 import java.util.List;
  30 
  31 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
  32 import org.graalvm.compiler.core.common.cfg.AbstractControlFlowGraph;
  33 import org.graalvm.compiler.core.common.cfg.BlockMap;
  34 import org.graalvm.compiler.debug.DebugContext;
  35 import org.graalvm.compiler.lir.StandardOp.BlockEndOp;
  36 import org.graalvm.compiler.lir.StandardOp.LabelOp;
  37 import org.graalvm.compiler.lir.gen.LIRGenerator;
  38 import org.graalvm.compiler.options.OptionValues;
  39 
  40 /**
  41  * This class implements the overall container for the LIR graph and directs its construction,
  42  * optimization, and finalization.
  43  */
  44 public final class LIR extends LIRGenerator.VariableProvider {
  45 
  46     private final AbstractControlFlowGraph<?> cfg;
  47 
  48     /**
  49      * The linear-scan ordered list of blocks.
  50      */
  51     private final AbstractBlockBase<?>[] linearScanOrder;
  52 
  53     /**
  54      * The order in which the code is emitted.
  55      */
  56     private final AbstractBlockBase<?>[] codeEmittingOrder;
  57 
  58     /**
  59      * Map from {@linkplain AbstractBlockBase block} to {@linkplain LIRInstruction}s. Note that we
  60      * are using {@link ArrayList} instead of {@link List} to avoid interface dispatch.
  61      */
  62     private final BlockMap<ArrayList<LIRInstruction>> lirInstructions;
  63 
  64     private boolean hasArgInCallerFrame;
  65 
  66     private final OptionValues options;
  67 
  68     private final DebugContext debug;
  69 
  70     /**
  71      * Creates a new LIR instance for the specified compilation.
  72      */
  73     public LIR(AbstractControlFlowGraph<?> cfg, AbstractBlockBase<?>[] linearScanOrder, AbstractBlockBase<?>[] codeEmittingOrder, OptionValues options, DebugContext debug) {
  74         this.cfg = cfg;
  75         this.codeEmittingOrder = codeEmittingOrder;
  76         this.linearScanOrder = linearScanOrder;
  77         this.lirInstructions = new BlockMap<>(cfg);
  78         this.options = options;
  79         this.debug = debug;
  80     }
  81 
  82     public AbstractControlFlowGraph<?> getControlFlowGraph() {
  83         return cfg;
  84     }
  85 
  86     public OptionValues getOptions() {
  87         return options;
  88     }
  89 
  90     public DebugContext getDebug() {
  91         return debug;
  92     }
  93 
  94     /**
  95      * Determines if any instruction in the LIR has debug info associated with it.
  96      */
  97     public boolean hasDebugInfo() {
  98         for (AbstractBlockBase<?> b : linearScanOrder()) {
  99             for (LIRInstruction op : getLIRforBlock(b)) {
 100                 if (op.hasState()) {
 101                     return true;
 102                 }
 103             }
 104         }
 105         return false;
 106     }
 107 
 108     public ArrayList<LIRInstruction> getLIRforBlock(AbstractBlockBase<?> block) {
 109         return lirInstructions.get(block);
 110     }
 111 
 112     public void setLIRforBlock(AbstractBlockBase<?> block, ArrayList<LIRInstruction> list) {
 113         assert getLIRforBlock(block) == null : "lir instruction list should only be initialized once";
 114         lirInstructions.put(block, list);
 115     }
 116 
 117     /**
 118      * Gets the linear scan ordering of blocks as an array.
 119      *
 120      * @return the blocks in linear scan order
 121      */
 122     public AbstractBlockBase<?>[] linearScanOrder() {
 123         return linearScanOrder;
 124     }
 125 
 126     public AbstractBlockBase<?>[] codeEmittingOrder() {
 127         return codeEmittingOrder;
 128     }
 129 
 130     public void setHasArgInCallerFrame() {
 131         hasArgInCallerFrame = true;
 132     }
 133 
 134     /**
 135      * Determines if any of the parameters to the method are passed via the stack where the
 136      * parameters are located in the caller's frame.
 137      */
 138     public boolean hasArgInCallerFrame() {
 139         return hasArgInCallerFrame;
 140     }
 141 
 142     /**
 143      * Gets the next non-{@code null} block in a list.
 144      *
 145      * @param blocks list of blocks
 146      * @param blockIndex index of the current block
 147      * @return the next block in the list that is none {@code null} or {@code null} if there is no
 148      *         such block
 149      */
 150     public static AbstractBlockBase<?> getNextBlock(AbstractBlockBase<?>[] blocks, int blockIndex) {
 151         for (int nextIndex = blockIndex + 1; nextIndex > 0 && nextIndex < blocks.length; nextIndex++) {
 152             AbstractBlockBase<?> nextBlock = blocks[nextIndex];
 153             if (nextBlock != null) {
 154                 return nextBlock;
 155             }
 156         }
 157         return null;
 158     }
 159 
 160     /**
 161      * Gets the exception edge (if any) originating at a given operation.
 162      */
 163     public static LabelRef getExceptionEdge(LIRInstruction op) {
 164         final LabelRef[] exceptionEdge = {null};
 165         op.forEachState(state -> {
 166             if (state.exceptionEdge != null) {
 167                 assert exceptionEdge[0] == null;
 168                 exceptionEdge[0] = state.exceptionEdge;
 169             }
 170         });
 171         return exceptionEdge[0];
 172     }
 173 
 174     /**
 175      * The maximum distance an operation with an {@linkplain #getExceptionEdge(LIRInstruction)
 176      * exception edge} can be from the last instruction of a LIR block. The value of 3 is based on a
 177      * non-void call operation that has an exception edge. Such a call may move the result to
 178      * another register and then spill it.
 179      * <p>
 180      * The rationale for such a constant is to limit the search for an insertion point when adding
 181      * move operations at the end of a block. Such moves must be inserted before all control flow
 182      * instructions.
 183      */
 184     public static final int MAX_EXCEPTION_EDGE_OP_DISTANCE_FROM_END = 3;
 185 
 186     public static boolean verifyBlock(LIR lir, AbstractBlockBase<?> block) {
 187         ArrayList<LIRInstruction> ops = lir.getLIRforBlock(block);
 188         if (ops.size() == 0) {
 189             return false;
 190         }
 191         assert ops.get(0) instanceof LabelOp : String.format("Not a Label %s (Block %s)", ops.get(0).getClass(), block);
 192         LIRInstruction opWithExceptionEdge = null;
 193         int index = 0;
 194         int lastIndex = ops.size() - 1;
 195         for (LIRInstruction op : ops.subList(0, lastIndex)) {
 196             assert !(op instanceof BlockEndOp) : String.format("BlockEndOp %s (Block %s)", op.getClass(), block);
 197             LabelRef exceptionEdge = getExceptionEdge(op);
 198             if (exceptionEdge != null) {
 199                 assert opWithExceptionEdge == null : "multiple ops with an exception edge not allowed";
 200                 opWithExceptionEdge = op;
 201                 int distanceFromEnd = lastIndex - index;
 202                 assert distanceFromEnd <= MAX_EXCEPTION_EDGE_OP_DISTANCE_FROM_END;
 203             }
 204             index++;
 205         }
 206         LIRInstruction end = ops.get(lastIndex);
 207         assert end instanceof BlockEndOp : String.format("Not a BlockEndOp %s (Block %s)", end.getClass(), block);
 208         return true;
 209     }
 210 
 211     public static boolean verifyBlocks(LIR lir, AbstractBlockBase<?>[] blocks) {
 212         for (AbstractBlockBase<?> block : blocks) {
 213             if (block == null) {
 214                 continue;
 215             }
 216             for (AbstractBlockBase<?> sux : block.getSuccessors()) {
 217                 assert Arrays.asList(blocks).contains(sux) : "missing successor from: " + block + "to: " + sux;
 218             }
 219             for (AbstractBlockBase<?> pred : block.getPredecessors()) {
 220                 assert Arrays.asList(blocks).contains(pred) : "missing predecessor from: " + block + "to: " + pred;
 221             }
 222             if (!verifyBlock(lir, block)) {
 223                 return false;
 224             }
 225         }
 226         return true;
 227     }
 228 
 229     public void resetLabels() {
 230 
 231         for (AbstractBlockBase<?> block : codeEmittingOrder()) {
 232             if (block == null) {
 233                 continue;
 234             }
 235             for (LIRInstruction inst : lirInstructions.get(block)) {
 236                 if (inst instanceof LabelOp) {
 237                     ((LabelOp) inst).getLabel().reset();
 238                 }
 239             }
 240         }
 241     }
 242 
 243 }