| /* |
| * 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.core.common.alloc; |
| |
| import java.util.ArrayList; |
| import java.util.BitSet; |
| import java.util.List; |
| import java.util.PriorityQueue; |
| |
| import org.graalvm.compiler.core.common.alloc.TraceBuilderResult.TrivialTracePredicate; |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.debug.Debug; |
| import org.graalvm.compiler.debug.Indent; |
| |
| /** |
| * Computes traces by starting at a trace head and keep adding predecessors as long as possible. |
| */ |
| public final class UniDirectionalTraceBuilder { |
| |
| public static TraceBuilderResult computeTraces(AbstractBlockBase<?> startBlock, AbstractBlockBase<?>[] blocks, TrivialTracePredicate pred) { |
| return new UniDirectionalTraceBuilder(blocks).build(startBlock, blocks, pred); |
| } |
| |
| private final PriorityQueue<AbstractBlockBase<?>> worklist; |
| private final BitSet processed; |
| /** |
| * Contains the number of unprocessed predecessors for every {@link AbstractBlockBase#getId() |
| * block}. |
| */ |
| private final int[] blocked; |
| private final Trace[] blockToTrace; |
| |
| private UniDirectionalTraceBuilder(AbstractBlockBase<?>[] blocks) { |
| processed = new BitSet(blocks.length); |
| worklist = new PriorityQueue<>(UniDirectionalTraceBuilder::compare); |
| assert (worklist != null); |
| |
| blocked = new int[blocks.length]; |
| blockToTrace = new Trace[blocks.length]; |
| for (AbstractBlockBase<?> block : blocks) { |
| blocked[block.getId()] = block.getPredecessorCount(); |
| } |
| } |
| |
| private static int compare(AbstractBlockBase<?> a, AbstractBlockBase<?> b) { |
| return Double.compare(b.probability(), a.probability()); |
| } |
| |
| private boolean processed(AbstractBlockBase<?> b) { |
| return processed.get(b.getId()); |
| } |
| |
| @SuppressWarnings("try") |
| private TraceBuilderResult build(AbstractBlockBase<?> startBlock, AbstractBlockBase<?>[] blocks, TrivialTracePredicate pred) { |
| try (Indent indent = Debug.logAndIndent("UniDirectionalTraceBuilder: start trace building: %s", startBlock)) { |
| ArrayList<Trace> traces = buildTraces(startBlock); |
| return TraceBuilderResult.create(blocks, traces, blockToTrace, pred); |
| } |
| } |
| |
| protected ArrayList<Trace> buildTraces(AbstractBlockBase<?> startBlock) { |
| ArrayList<Trace> traces = new ArrayList<>(); |
| // add start block |
| worklist.add(startBlock); |
| // process worklist |
| while (!worklist.isEmpty()) { |
| AbstractBlockBase<?> block = worklist.poll(); |
| assert block != null; |
| if (!processed(block)) { |
| Trace trace = new Trace(startTrace(block)); |
| for (AbstractBlockBase<?> traceBlock : trace.getBlocks()) { |
| blockToTrace[traceBlock.getId()] = trace; |
| } |
| trace.setId(traces.size()); |
| traces.add(trace); |
| } |
| } |
| return traces; |
| } |
| |
| /** |
| * Build a new trace starting at {@code block}. |
| */ |
| @SuppressWarnings("try") |
| private List<AbstractBlockBase<?>> startTrace(AbstractBlockBase<?> block) { |
| assert checkPredecessorsProcessed(block); |
| ArrayList<AbstractBlockBase<?>> trace = new ArrayList<>(); |
| int blockNumber = 0; |
| try (Indent i = Debug.logAndIndent("StartTrace: %s", block)) { |
| for (AbstractBlockBase<?> currentBlock = block; currentBlock != null; currentBlock = selectNext(currentBlock)) { |
| Debug.log("add %s (prob: %f)", currentBlock, currentBlock.probability()); |
| processed.set(currentBlock.getId()); |
| trace.add(currentBlock); |
| unblock(currentBlock); |
| currentBlock.setLinearScanNumber(blockNumber++); |
| } |
| } |
| return trace; |
| } |
| |
| private boolean checkPredecessorsProcessed(AbstractBlockBase<?> block) { |
| for (AbstractBlockBase<?> pred : block.getPredecessors()) { |
| if (!processed(pred)) { |
| assert false : "Predecessor unscheduled: " + pred; |
| return false; |
| } |
| |
| } |
| return true; |
| } |
| |
| /** |
| * Decrease the {@link #blocked} count for all predecessors and add them to the worklist once |
| * the count reaches 0. |
| */ |
| private void unblock(AbstractBlockBase<?> currentBlock) { |
| for (AbstractBlockBase<?> successor : currentBlock.getSuccessors()) { |
| if (!processed(successor)) { |
| int blockCount = --blocked[successor.getId()]; |
| assert blockCount >= 0; |
| if (blockCount == 0) { |
| worklist.add(successor); |
| } |
| } |
| } |
| } |
| |
| /** |
| * @return The unprocessed predecessor with the highest probability, or {@code null}. |
| */ |
| private AbstractBlockBase<?> selectNext(AbstractBlockBase<?> currentBlock) { |
| AbstractBlockBase<?> next = null; |
| for (AbstractBlockBase<?> succ : currentBlock.getSuccessors()) { |
| if (!processed(succ) && (next == null || succ.probability() > next.probability())) { |
| next = succ; |
| } |
| } |
| return next; |
| } |
| } |