1 /*
2 * Copyright (c) 2013, 2019, 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
24
25 package org.graalvm.compiler.phases.common;
26
27 import java.util.List;
28
29 import jdk.internal.vm.compiler.collections.EconomicMap;
30 import org.graalvm.compiler.debug.GraalError;
31 import org.graalvm.compiler.graph.Node;
32 import org.graalvm.compiler.nodes.AbstractBeginNode;
33 import org.graalvm.compiler.nodes.AbstractMergeNode;
34 import org.graalvm.compiler.nodes.DeoptimizingNode;
35 import org.graalvm.compiler.nodes.FixedNode;
36 import org.graalvm.compiler.nodes.FrameState;
37 import org.graalvm.compiler.nodes.LoopBeginNode;
38 import org.graalvm.compiler.nodes.LoopExitNode;
39 import org.graalvm.compiler.nodes.StateSplit;
40 import org.graalvm.compiler.nodes.StructuredGraph;
41 import org.graalvm.compiler.nodes.StructuredGraph.GuardsStage;
42 import org.graalvm.compiler.nodes.util.GraphUtil;
43 import org.graalvm.compiler.phases.Phase;
44 import org.graalvm.compiler.phases.graph.ReentrantNodeIterator;
45 import org.graalvm.compiler.phases.graph.ReentrantNodeIterator.NodeIteratorClosure;
46
47 import jdk.vm.ci.code.BytecodeFrame;
48
49 /**
50 * This phase transfers {@link FrameState} nodes from {@link StateSplit} nodes to
51 * {@link DeoptimizingNode DeoptimizingNodes}.
52 *
53 * This allow to enter the {@link GuardsStage#AFTER_FSA AFTER_FSA} stage of the graph where no new
54 * node that may cause deoptimization can be introduced anymore.
55 * <p>
56 * This Phase processes the graph in post order, assigning the {@link FrameState} from the last
57 * {@link StateSplit} node to {@link DeoptimizingNode DeoptimizingNodes}.
58 */
59 public class FrameStateAssignmentPhase extends Phase {
60
61 private static class FrameStateAssignmentClosure extends NodeIteratorClosure<FrameState> {
62
63 @Override
64 protected FrameState processNode(FixedNode node, FrameState previousState) {
65 FrameState currentState = previousState;
66 if (node instanceof DeoptimizingNode.DeoptBefore) {
67 DeoptimizingNode.DeoptBefore deopt = (DeoptimizingNode.DeoptBefore) node;
68 if (deopt.canDeoptimize() && deopt.stateBefore() == null) {
69 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
70 deopt.setStateBefore(currentState);
71 }
72 }
73
74 if (node instanceof StateSplit) {
75 StateSplit stateSplit = (StateSplit) node;
76 FrameState stateAfter = stateSplit.stateAfter();
77 if (stateAfter != null) {
78 if (stateAfter.bci == BytecodeFrame.INVALID_FRAMESTATE_BCI) {
79 currentState = null;
80 } else {
81 currentState = stateAfter;
82 }
83 stateSplit.setStateAfter(null);
84 }
85 }
86
87 if (node instanceof DeoptimizingNode.DeoptDuring) {
88 DeoptimizingNode.DeoptDuring deopt = (DeoptimizingNode.DeoptDuring) node;
89 if (deopt.canDeoptimize() && deopt.stateDuring() == null) {
90 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
91 deopt.computeStateDuring(currentState);
92 }
93 }
94
95 if (node instanceof DeoptimizingNode.DeoptAfter) {
96 DeoptimizingNode.DeoptAfter deopt = (DeoptimizingNode.DeoptAfter) node;
97 if (deopt.canDeoptimize() && deopt.stateAfter() == null) {
98 GraalError.guarantee(currentState != null, "no FrameState at DeoptimizingNode %s", deopt);
99 deopt.setStateAfter(currentState);
100 }
101 }
102
103 return currentState;
104 }
105
106 @Override
107 protected FrameState merge(AbstractMergeNode merge, List<FrameState> states) {
108 FrameState singleFrameState = singleFrameState(states);
109 return singleFrameState == null ? merge.stateAfter() : singleFrameState;
110 }
111
112 @Override
113 protected FrameState afterSplit(AbstractBeginNode node, FrameState oldState) {
114 return oldState;
115 }
116
117 @Override
118 protected EconomicMap<LoopExitNode, FrameState> processLoop(LoopBeginNode loop, FrameState initialState) {
119 return ReentrantNodeIterator.processLoop(this, loop, initialState).exitStates;
120 }
121 }
122
123 @Override
124 protected void run(StructuredGraph graph) {
125 assert !graph.getGuardsStage().allowsFloatingGuards() && !hasFloatingDeopts(graph);
126 if (graph.getGuardsStage().areFrameStatesAtSideEffects()) {
127 ReentrantNodeIterator.apply(new FrameStateAssignmentClosure(), graph.start(), null);
128 graph.setGuardsStage(GuardsStage.AFTER_FSA);
129 graph.getNodes(FrameState.TYPE).filter(state -> state.hasNoUsages()).forEach(GraphUtil::killWithUnusedFloatingInputs);
130 }
131 }
132
133 private static boolean hasFloatingDeopts(StructuredGraph graph) {
134 for (Node n : graph.getNodes()) {
135 if (n instanceof DeoptimizingNode && GraphUtil.isFloatingNode(n)) {
136 DeoptimizingNode deoptimizingNode = (DeoptimizingNode) n;
137 if (deoptimizingNode.canDeoptimize()) {
138 return true;
139 }
140 }
141 }
142 return false;
143 }
144
145 private static FrameState singleFrameState(List<FrameState> states) {
146 FrameState singleState = states.get(0);
147 for (int i = 1; i < states.size(); ++i) {
148 if (states.get(i) != singleState) {
149 return null;
150 }
151 }
152 if (singleState != null && singleState.bci != BytecodeFrame.INVALID_FRAMESTATE_BCI) {
153 return singleState;
154 }
155 return null;
156 }
157
158 @Override
159 public boolean checkContract() {
160 // TODO GR-1409
161 return false;
162 }
163 }