1 /*
2 * Copyright (c) 2011, 2012, 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.util;
24
25 import java.util.ArrayList;
26 import java.util.List;
27
28 import org.graalvm.compiler.core.common.cfg.Loop;
29 import org.graalvm.compiler.debug.Debug;
30 import org.graalvm.compiler.debug.GraalError;
31 import org.graalvm.compiler.graph.GraalGraphError;
32 import org.graalvm.compiler.graph.Node;
33 import org.graalvm.compiler.graph.NodeBitMap;
34 import org.graalvm.compiler.nodes.AbstractEndNode;
35 import org.graalvm.compiler.nodes.AbstractMergeNode;
36 import org.graalvm.compiler.nodes.ConstantNode;
37 import org.graalvm.compiler.nodes.EndNode;
38 import org.graalvm.compiler.nodes.FixedNode;
39 import org.graalvm.compiler.nodes.FrameState;
40 import org.graalvm.compiler.nodes.FullInfopointNode;
41 import org.graalvm.compiler.nodes.LoopBeginNode;
42 import org.graalvm.compiler.nodes.LoopExitNode;
43 import org.graalvm.compiler.nodes.PhiNode;
44 import org.graalvm.compiler.nodes.ProxyNode;
45 import org.graalvm.compiler.nodes.StateSplit;
46 import org.graalvm.compiler.nodes.StructuredGraph;
47 import org.graalvm.compiler.nodes.StructuredGraph.GuardsStage;
48 import org.graalvm.compiler.nodes.StructuredGraph.ScheduleResult;
49 import org.graalvm.compiler.nodes.ValueNode;
50 import org.graalvm.compiler.nodes.VirtualState;
51 import org.graalvm.compiler.nodes.VirtualState.NodeClosure;
52 import org.graalvm.compiler.nodes.cfg.Block;
53 import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;
54 import org.graalvm.compiler.phases.graph.ReentrantBlockIterator;
55 import org.graalvm.compiler.phases.graph.ReentrantBlockIterator.BlockIteratorClosure;
56 import org.graalvm.compiler.phases.graph.StatelessPostOrderNodeIterator;
57 import org.graalvm.compiler.phases.schedule.SchedulePhase;
58 import org.graalvm.compiler.phases.schedule.SchedulePhase.SchedulingStrategy;
59 import org.graalvm.util.EconomicMap;
60 import org.graalvm.util.Equivalence;
61
62 public final class GraphOrder {
63
64 private GraphOrder() {
65 }
66
67 /**
68 * Quick (and imprecise) assertion that there are no (invalid) cycles in the given graph. First,
69 * an ordered list of all nodes in the graph (a total ordering) is created. A second run over
70 * this list checks whether inputs are scheduled before their usages.
71 *
72 * @param graph the graph to be checked.
73 * @throws AssertionError if a cycle was detected.
74 */
75 public static boolean assertNonCyclicGraph(StructuredGraph graph) {
76 List<Node> order = createOrder(graph);
77 NodeBitMap visited = graph.createNodeBitMap();
78 visited.clearAll();
79 for (Node node : order) {
80 if (node instanceof PhiNode && ((PhiNode) node).merge() instanceof LoopBeginNode) {
81 assert visited.isMarked(((PhiNode) node).valueAt(0));
82 // nothing to do
83 } else {
84 for (Node input : node.inputs()) {
85 if (!visited.isMarked(input)) {
86 if (input instanceof FrameState) {
87 // nothing to do - frame states are known, allowed cycles
88 } else {
89 assert false : "unexpected cycle detected at input " + node + " -> " + input;
90 }
91 }
92 }
93 }
94 visited.mark(node);
95 }
96 return true;
97 }
98
99 private static List<Node> createOrder(StructuredGraph graph) {
100 final ArrayList<Node> nodes = new ArrayList<>();
101 final NodeBitMap visited = graph.createNodeBitMap();
102
103 new StatelessPostOrderNodeIterator(graph.start()) {
104 @Override
105 protected void node(FixedNode node) {
106 visitForward(nodes, visited, node, false);
107 }
108 }.apply();
109 return nodes;
110 }
111
112 private static void visitForward(ArrayList<Node> nodes, NodeBitMap visited, Node node, boolean floatingOnly) {
113 try {
114 assert node == null || node.isAlive() : node + " not alive";
115 if (node != null && !visited.isMarked(node)) {
116 if (floatingOnly && node instanceof FixedNode) {
117 throw new GraalError("unexpected reference to fixed node: %s (this indicates an unexpected cycle)", node);
118 }
119 visited.mark(node);
120 FrameState stateAfter = null;
121 if (node instanceof StateSplit) {
122 stateAfter = ((StateSplit) node).stateAfter();
123 }
124 for (Node input : node.inputs()) {
125 if (input != stateAfter) {
126 visitForward(nodes, visited, input, true);
127 }
128 }
129 if (node instanceof EndNode) {
130 EndNode end = (EndNode) node;
131 for (PhiNode phi : end.merge().phis()) {
132 visitForward(nodes, visited, phi.valueAt(end), true);
133 }
134 }
135 nodes.add(node);
136 if (node instanceof AbstractMergeNode) {
137 for (PhiNode phi : ((AbstractMergeNode) node).phis()) {
138 visited.mark(phi);
139 nodes.add(phi);
140 }
141 }
142 if (stateAfter != null) {
143 visitForward(nodes, visited, stateAfter, true);
144 }
145 }
146 } catch (GraalError e) {
147 throw GraalGraphError.transformAndAddContext(e, node);
148 }
149 }
150
151 /**
152 * This method schedules the graph and makes sure that, for every node, all inputs are available
153 * at the position where it is scheduled. This is a very expensive assertion.
154 */
155 public static boolean assertSchedulableGraph(final StructuredGraph graph) {
156 assert graph.getGuardsStage() != GuardsStage.AFTER_FSA : "Cannot use the BlockIteratorClosure after FrameState Assignment, HIR Loop Data Structures are no longer valid.";
157 try {
158 final SchedulePhase schedulePhase = new SchedulePhase(SchedulingStrategy.LATEST_OUT_OF_LOOPS, true);
159 final EconomicMap<LoopBeginNode, NodeBitMap> loopEntryStates = EconomicMap.create(Equivalence.IDENTITY);
160 schedulePhase.apply(graph, false);
161 final ScheduleResult schedule = graph.getLastSchedule();
162
163 BlockIteratorClosure<NodeBitMap> closure = new BlockIteratorClosure<NodeBitMap>() {
164
165 @Override
166 protected List<NodeBitMap> processLoop(Loop<Block> loop, NodeBitMap initialState) {
167 return ReentrantBlockIterator.processLoop(this, loop, initialState).exitStates;
168 }
169
170 @Override
171 protected NodeBitMap processBlock(final Block block, final NodeBitMap currentState) {
172 final List<Node> list = graph.getLastSchedule().getBlockToNodesMap().get(block);
173
174 /*
175 * A stateAfter is not valid directly after its associated state split, but
176 * right before the next fixed node. Therefore a pending stateAfter is kept that
177 * will be checked at the correct position.
178 */
179 FrameState pendingStateAfter = null;
180 for (final Node node : list) {
181 if (node instanceof ValueNode) {
182 FrameState stateAfter = node instanceof StateSplit ? ((StateSplit) node).stateAfter() : null;
183 if (node instanceof FullInfopointNode) {
184 stateAfter = ((FullInfopointNode) node).getState();
185 }
186
187 if (pendingStateAfter != null && node instanceof FixedNode) {
188 pendingStateAfter.applyToNonVirtual(new NodeClosure<Node>() {
189 @Override
190 public void apply(Node usage, Node nonVirtualNode) {
191 assert currentState.isMarked(nonVirtualNode) || nonVirtualNode instanceof VirtualObjectNode || nonVirtualNode instanceof ConstantNode : nonVirtualNode +
192 " not available at virtualstate " + usage + " before " + node + " in block " + block + " \n" + list;
193 }
194 });
195 pendingStateAfter = null;
196 }
197
198 if (node instanceof AbstractMergeNode) {
199 // phis aren't scheduled, so they need to be added explicitly
200 currentState.markAll(((AbstractMergeNode) node).phis());
201 if (node instanceof LoopBeginNode) {
202 // remember the state at the loop entry, it's restored at exits
203 loopEntryStates.put((LoopBeginNode) node, currentState.copy());
204 }
205 } else if (node instanceof ProxyNode) {
206 assert false : "proxy nodes should not be in the schedule";
207 } else if (node instanceof LoopExitNode) {
208 if (graph.hasValueProxies()) {
209 for (ProxyNode proxy : ((LoopExitNode) node).proxies()) {
210 for (Node input : proxy.inputs()) {
211 if (input != proxy.proxyPoint()) {
212 assert currentState.isMarked(input) : input + " not available at " + proxy + " in block " + block + "\n" + list;
213 }
214 }
215 }
216
217 // loop contents are only accessible via proxies at the exit
218 currentState.clearAll();
219 currentState.markAll(loopEntryStates.get(((LoopExitNode) node).loopBegin()));
220 }
221 // Loop proxies aren't scheduled, so they need to be added
222 // explicitly
223 currentState.markAll(((LoopExitNode) node).proxies());
224 } else {
225 for (Node input : node.inputs()) {
226 if (input != stateAfter) {
227 if (input instanceof FrameState) {
228 ((FrameState) input).applyToNonVirtual(new VirtualState.NodeClosure<Node>() {
229 @Override
230 public void apply(Node usage, Node nonVirtual) {
231 assert currentState.isMarked(nonVirtual) : nonVirtual + " not available at " + node + " in block " + block + "\n" + list;
232 }
233 });
234 } else {
235 assert currentState.isMarked(input) || input instanceof VirtualObjectNode || input instanceof ConstantNode : input + " not available at " + node +
236 " in block " + block + "\n" + list;
237 }
238 }
239 }
240 }
241 if (node instanceof AbstractEndNode) {
242 AbstractMergeNode merge = ((AbstractEndNode) node).merge();
243 for (PhiNode phi : merge.phis()) {
244 ValueNode phiValue = phi.valueAt((AbstractEndNode) node);
245 assert phiValue == null || currentState.isMarked(phiValue) || phiValue instanceof ConstantNode : phiValue + " not available at phi " + phi + " / end " + node +
246 " in block " + block;
247 }
248 }
249 if (stateAfter != null) {
250 assert pendingStateAfter == null;
251 pendingStateAfter = stateAfter;
252 }
253 currentState.mark(node);
254 }
255 }
256 if (pendingStateAfter != null) {
257 pendingStateAfter.applyToNonVirtual(new NodeClosure<Node>() {
258 @Override
259 public void apply(Node usage, Node nonVirtualNode) {
260 assert currentState.isMarked(nonVirtualNode) || nonVirtualNode instanceof VirtualObjectNode || nonVirtualNode instanceof ConstantNode : nonVirtualNode +
261 " not available at virtualstate " + usage + " at end of block " + block + " \n" + list;
262 }
263 });
264 }
265 return currentState;
266 }
267
268 @Override
269 protected NodeBitMap merge(Block merge, List<NodeBitMap> states) {
270 NodeBitMap result = states.get(0);
271 for (int i = 1; i < states.size(); i++) {
272 result.intersect(states.get(i));
273 }
274 return result;
275 }
276
277 @Override
278 protected NodeBitMap getInitialState() {
279 NodeBitMap ret = graph.createNodeBitMap();
280 ret.markAll(graph.getNodes().filter(ConstantNode.class));
281 return ret;
282 }
283
284 @Override
285 protected NodeBitMap cloneState(NodeBitMap oldState) {
286 return oldState.copy();
287 }
288 };
289
290 ReentrantBlockIterator.apply(closure, schedule.getCFG().getStartBlock());
291
292 } catch (Throwable t) {
293 Debug.handle(t);
294 }
295 return true;
296 }
297 }