1 /*
2 * Copyright (c) 2011, 2017, 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 org.graalvm.compiler.nodes.memory;
24
25 import static org.graalvm.compiler.nodeinfo.InputType.Memory;
26 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_2;
27 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;
28
29 import org.graalvm.compiler.core.common.LIRKind;
30 import org.graalvm.compiler.core.common.type.ObjectStamp;
31 import org.graalvm.compiler.core.common.type.Stamp;
32 import org.graalvm.compiler.debug.DebugCloseable;
33 import org.graalvm.compiler.graph.Node;
34 import org.graalvm.compiler.graph.NodeClass;
35 import org.graalvm.compiler.graph.spi.Canonicalizable;
36 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
37 import org.graalvm.compiler.nodeinfo.NodeInfo;
38 import org.graalvm.compiler.nodes.ValueNodeUtil;
39 import org.graalvm.compiler.nodes.ValuePhiNode;
40 import org.graalvm.compiler.nodes.extended.GuardingNode;
41 import org.graalvm.compiler.nodes.memory.address.AddressNode;
42 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
43 import org.graalvm.word.LocationIdentity;
44
45 /**
46 * A floating read of a value from memory specified in terms of an object base and an object
47 * relative location. This node does not null check the object.
48 */
49 @NodeInfo(nameTemplate = "Read#{p#location/s}", cycles = CYCLES_2, size = SIZE_1)
50 public final class FloatingReadNode extends FloatingAccessNode implements LIRLowerableAccess, Canonicalizable {
51 public static final NodeClass<FloatingReadNode> TYPE = NodeClass.create(FloatingReadNode.class);
52
53 @OptionalInput(Memory) MemoryNode lastLocationAccess;
54
55 public FloatingReadNode(AddressNode address, LocationIdentity location, MemoryNode lastLocationAccess, Stamp stamp) {
56 this(address, location, lastLocationAccess, stamp, null, BarrierType.NONE);
57 }
58
59 public FloatingReadNode(AddressNode address, LocationIdentity location, MemoryNode lastLocationAccess, Stamp stamp, GuardingNode guard) {
60 this(address, location, lastLocationAccess, stamp, guard, BarrierType.NONE);
61 }
62
63 public FloatingReadNode(AddressNode address, LocationIdentity location, MemoryNode lastLocationAccess, Stamp stamp, GuardingNode guard, BarrierType barrierType) {
64 super(TYPE, address, location, stamp, guard, barrierType);
65 this.lastLocationAccess = lastLocationAccess;
66
67 // The input to floating reads must be always non-null or have at least a guard.
68 assert guard != null || !(address.getBase().stamp() instanceof ObjectStamp) || address.getBase() instanceof ValuePhiNode ||
69 ((ObjectStamp) address.getBase().stamp()).nonNull() : address.getBase();
70 }
71
72 @Override
73 public MemoryNode getLastLocationAccess() {
74 return lastLocationAccess;
75 }
76
77 @Override
78 public void setLastLocationAccess(MemoryNode newlla) {
79 updateUsages(ValueNodeUtil.asNode(lastLocationAccess), ValueNodeUtil.asNode(newlla));
80 lastLocationAccess = newlla;
81 }
82
83 @Override
84 public void generate(NodeLIRBuilderTool gen) {
85 LIRKind readKind = gen.getLIRGeneratorTool().getLIRKind(stamp());
86 gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitLoad(readKind, gen.operand(address), null));
87 }
88
89 @Override
90 public Node canonical(CanonicalizerTool tool) {
91 Node result = ReadNode.canonicalizeRead(this, getAddress(), getLocationIdentity(), tool);
92 if (result != this) {
93 return result;
94 }
95 if (tool.canonicalizeReads() && getAddress().hasMoreThanOneUsage() && lastLocationAccess instanceof WriteNode) {
96 WriteNode write = (WriteNode) lastLocationAccess;
97 if (write.getAddress() == getAddress() && write.getAccessStamp().isCompatible(getAccessStamp())) {
98 // Same memory location with no intervening write
99 return write.value();
100 }
101 }
102 return this;
103 }
104
105 @SuppressWarnings("try")
106 @Override
107 public FixedAccessNode asFixedNode() {
108 try (DebugCloseable position = withNodeSourcePosition()) {
109 ReadNode result = graph().add(new ReadNode(getAddress(), getLocationIdentity(), stamp(), getBarrierType()));
110 result.setGuard(getGuard());
111 return result;
112 }
113 }
114
115 @Override
116 public boolean verify() {
117 MemoryNode lla = getLastLocationAccess();
118 assert lla != null || getLocationIdentity().isImmutable() : "lastLocationAccess of " + this + " shouldn't be null for mutable location identity " + getLocationIdentity();
119 return super.verify();
120 }
121
122 @Override
123 public Stamp getAccessStamp() {
124 return stamp();
125 }
126 }