1 /*
2 * Copyright (c) 2013, 2016, 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.phases.common;
24
25 import java.util.List;
26 import java.util.Map;
27
28 import org.graalvm.compiler.debug.GraalError;
29 import org.graalvm.compiler.graph.Node;
30 import org.graalvm.compiler.nodes.AbstractBeginNode;
31 import org.graalvm.compiler.nodes.AbstractMergeNode;
32 import org.graalvm.compiler.nodes.DeoptimizingNode;
33 import org.graalvm.compiler.nodes.FixedNode;
34 import org.graalvm.compiler.nodes.FrameState;
35 import org.graalvm.compiler.nodes.LoopBeginNode;
36 import org.graalvm.compiler.nodes.LoopExitNode;
37 import org.graalvm.compiler.nodes.StateSplit;
38 import org.graalvm.compiler.nodes.StructuredGraph;
39 import org.graalvm.compiler.nodes.StructuredGraph.GuardsStage;
40 import org.graalvm.compiler.nodes.util.GraphUtil;
41 import org.graalvm.compiler.phases.Phase;
42 import org.graalvm.compiler.phases.graph.ReentrantNodeIterator;
43 import org.graalvm.compiler.phases.graph.ReentrantNodeIterator.NodeIteratorClosure;
44
45 /**
46 * This phase transfers {@link FrameState} nodes from {@link StateSplit} nodes to
47 * {@link DeoptimizingNode DeoptimizingNodes}.
48 *
49 * This allow to enter the {@link GuardsStage#AFTER_FSA AFTER_FSA} stage of the graph where no new
50 * node that may cause deoptimization can be introduced anymore.
51 * <p>
52 * This Phase processes the graph in post order, assigning the {@link FrameState} from the last
53 * {@link StateSplit} node to {@link DeoptimizingNode DeoptimizingNodes}.
54 */
55 public class FrameStateAssignmentPhase extends Phase {
56
57 private static class FrameStateAssignmentClosure extends NodeIteratorClosure<FrameState> {
58
59 @Override
60 protected FrameState processNode(FixedNode node, FrameState previousState) {
61 FrameState currentState = previousState;
62 if (node instanceof DeoptimizingNode.DeoptBefore) {
63 DeoptimizingNode.DeoptBefore deopt = (DeoptimizingNode.DeoptBefore) node;
64 if (deopt.canDeoptimize() && deopt.stateBefore() == null) {
65 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
66 deopt.setStateBefore(currentState);
67 }
68 }
69
70 if (node instanceof StateSplit) {
71 StateSplit stateSplit = (StateSplit) node;
72 FrameState stateAfter = stateSplit.stateAfter();
73 if (stateAfter != null) {
74 currentState = stateAfter;
75 stateSplit.setStateAfter(null);
76 }
77 }
78
79 if (node instanceof DeoptimizingNode.DeoptDuring) {
80 DeoptimizingNode.DeoptDuring deopt = (DeoptimizingNode.DeoptDuring) node;
81 if (deopt.canDeoptimize()) {
82 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
83 deopt.computeStateDuring(currentState);
84 }
85 }
86
87 if (node instanceof DeoptimizingNode.DeoptAfter) {
88 DeoptimizingNode.DeoptAfter deopt = (DeoptimizingNode.DeoptAfter) node;
89 if (deopt.canDeoptimize() && deopt.stateAfter() == null) {
90 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
91 deopt.setStateAfter(currentState);
92 }
93 }
94
95 return currentState;
96 }
97
98 @Override
99 protected FrameState merge(AbstractMergeNode merge, List<FrameState> states) {
100 FrameState singleFrameState = singleFrameState(states);
101 return singleFrameState == null ? merge.stateAfter() : singleFrameState;
102 }
103
104 @Override
105 protected FrameState afterSplit(AbstractBeginNode node, FrameState oldState) {
106 return oldState;
107 }
108
109 @Override
110 protected Map<LoopExitNode, FrameState> processLoop(LoopBeginNode loop, FrameState initialState) {
111 return ReentrantNodeIterator.processLoop(this, loop, initialState).exitStates;
112 }
113 }
114
115 @Override
116 protected void run(StructuredGraph graph) {
117 assert !graph.getGuardsStage().allowsFloatingGuards() && !hasFloatingDeopts(graph);
118 if (graph.getGuardsStage().areFrameStatesAtSideEffects()) {
119 ReentrantNodeIterator.apply(new FrameStateAssignmentClosure(), graph.start(), null);
120 graph.setGuardsStage(GuardsStage.AFTER_FSA);
121 graph.getNodes(FrameState.TYPE).filter(state -> state.hasNoUsages()).forEach(GraphUtil::killWithUnusedFloatingInputs);
122 }
123 }
124
125 private static boolean hasFloatingDeopts(StructuredGraph graph) {
126 for (Node n : graph.getNodes()) {
127 if (n instanceof DeoptimizingNode && GraphUtil.isFloatingNode(n)) {
128 DeoptimizingNode deoptimizingNode = (DeoptimizingNode) n;
129 if (deoptimizingNode.canDeoptimize()) {
130 return true;
131 }
132 }
133 }
134 return false;
135 }
136
137 private static FrameState singleFrameState(List<FrameState> states) {
138 FrameState singleState = states.get(0);
139 for (int i = 1; i < states.size(); ++i) {
140 if (states.get(i) != singleState) {
141 return null;
142 }
143 }
144 return singleState;
145 }
146
147 @Override
148 public boolean checkContract() {
149 // TODO GR-1409
150 return false;
151 }
152 }