ReadRegisterNode.java revision 12651:6ef01bd40ce2 
1/*
2 * Copyright (c) 2012, 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 */
23package org.graalvm.compiler.replacements.nodes;
24
25import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;
26import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;
27
28import org.graalvm.compiler.core.common.LIRKind;
29import org.graalvm.compiler.core.common.type.StampFactory;
30import org.graalvm.compiler.graph.NodeClass;
31import org.graalvm.compiler.nodeinfo.NodeInfo;
32import org.graalvm.compiler.nodeinfo.Verbosity;
33import org.graalvm.compiler.nodes.FixedWithNextNode;
34import org.graalvm.compiler.nodes.spi.LIRLowerable;
35import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
36
37import jdk.vm.ci.code.Register;
38import jdk.vm.ci.meta.JavaKind;
39import jdk.vm.ci.meta.Value;
40
41/**
42 * Access the value of a specific register.
43 */
44@NodeInfo(nameTemplate = "ReadRegister %{p#register}", cycles = CYCLES_1, size = SIZE_1)
45public final class ReadRegisterNode extends FixedWithNextNode implements LIRLowerable {
46
47    public static final NodeClass<ReadRegisterNode> TYPE = NodeClass.create(ReadRegisterNode.class);
48    /**
49     * The fixed register to access.
50     */
51    protected final Register register;
52
53    /**
54     * When true, subsequent uses of this node use the fixed register; when false, the value is
55     * moved into a new virtual register so that the fixed register is not seen by uses.
56     */
57    protected final boolean directUse;
58
59    /**
60     * When true, this node is also an implicit definition of the value for the register allocator,
61     * i.e., the register is an implicit incoming value; when false, the register must be defined in
62     * the same method or must be an register excluded from register allocation.
63     */
64    protected final boolean incoming;
65
66    public ReadRegisterNode(Register register, JavaKind kind, boolean directUse, boolean incoming) {
67        super(TYPE, StampFactory.forKind(kind));
68        assert register != null;
69        this.register = register;
70        this.directUse = directUse;
71        this.incoming = incoming;
72    }
73
74    public ReadRegisterNode(Register register, boolean directUse, boolean incoming) {
75        super(TYPE, StampFactory.forNodeIntrinsic());
76        assert register != null;
77        this.register = register;
78        this.directUse = directUse;
79        this.incoming = incoming;
80    }
81
82    @Override
83    public void generate(NodeLIRBuilderTool generator) {
84        LIRKind kind = generator.getLIRGeneratorTool().getLIRKind(stamp());
85        Value result = register.asValue(kind);
86        if (incoming) {
87            generator.getLIRGeneratorTool().emitIncomingValues(new Value[]{result});
88        }
89        if (!directUse) {
90            result = generator.getLIRGeneratorTool().emitMove(result);
91        }
92        generator.setResult(this, result);
93    }
94
95    @Override
96    public String toString(Verbosity verbosity) {
97        if (verbosity == Verbosity.Name) {
98            return super.toString(Verbosity.Name) + "%" + register;
99        } else {
100            return super.toString(verbosity);
101        }
102    }
103}
104