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