Mercurial > hg > graal-jvmci-8
comparison graal/Compiler/src/com/sun/c1x/graph/CriticalEdgeFinder.java @ 2507:9ec15d6914ca
Pull over of compiler from maxine repository.
author | Thomas Wuerthinger <thomas@wuerthinger.net> |
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date | Wed, 27 Apr 2011 11:43:22 +0200 |
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2506:4a3bf8a5bf41 | 2507:9ec15d6914ca |
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1 /* | |
2 * Copyright (c) 2009, 2010, 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 com.sun.c1x.graph; | |
24 | |
25 import java.util.*; | |
26 | |
27 import com.sun.c1x.*; | |
28 import com.sun.c1x.debug.*; | |
29 import com.sun.c1x.ir.*; | |
30 | |
31 /** | |
32 * This class finds and splits "critical" edges in the control flow graph. | |
33 * An edge between two blocks {@code A} and {@code B} is "critical" if {@code A} | |
34 * has more than one successor and {@code B} has more than one predecessor. Such | |
35 * edges are split by adding a block between the two blocks. | |
36 * | |
37 * @author Thomas Wuerthinger | |
38 */ | |
39 public class CriticalEdgeFinder implements BlockClosure { | |
40 | |
41 private final IR ir; | |
42 | |
43 /** | |
44 * The graph edges represented as a map from source to target nodes. | |
45 * Using a linked hash map makes compilation tracing more deterministic and thus eases debugging. | |
46 */ | |
47 private Map<BlockBegin, Set<BlockBegin>> edges = C1XOptions.DetailedAsserts ? | |
48 new LinkedHashMap<BlockBegin, Set<BlockBegin>>() : | |
49 new HashMap<BlockBegin, Set<BlockBegin>>(); | |
50 | |
51 public CriticalEdgeFinder(IR ir) { | |
52 this.ir = ir; | |
53 } | |
54 | |
55 public void apply(BlockBegin block) { | |
56 if (block.numberOfSux() >= 2) { | |
57 for (BlockBegin succ : block.end().successors()) { | |
58 if (succ.numberOfPreds() >= 2) { | |
59 // TODO: (tw) probably we don't have to make it a critical edge if succ only contains the _same_ predecessor multiple times. | |
60 recordCriticalEdge(block, succ); | |
61 } | |
62 } | |
63 } | |
64 } | |
65 | |
66 private void recordCriticalEdge(BlockBegin block, BlockBegin succ) { | |
67 if (!edges.containsKey(block)) { | |
68 edges.put(block, new HashSet<BlockBegin>()); | |
69 } | |
70 | |
71 edges.get(block).add(succ); | |
72 } | |
73 | |
74 public void splitCriticalEdges() { | |
75 for (BlockBegin from : edges.keySet()) { | |
76 for (BlockBegin to : edges.get(from)) { | |
77 BlockBegin split = ir.splitEdge(from, to); | |
78 if (C1XOptions.PrintHIR) { | |
79 TTY.println("Split edge between block %d and block %d, creating new block %d", from.blockID, to.blockID, split.blockID); | |
80 } | |
81 } | |
82 } | |
83 } | |
84 } |