/*
* Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package org.graalvm.compiler.nodes.util;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.graalvm.compiler.bytecode.Bytecode;
import org.graalvm.compiler.code.SourceStackTraceBailoutException;
import org.graalvm.compiler.core.common.spi.ConstantFieldProvider;
import org.graalvm.compiler.core.common.type.ObjectStamp;
import org.graalvm.compiler.debug.Debug;
import org.graalvm.compiler.graph.Graph;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeSourcePosition;
import org.graalvm.compiler.graph.NodeStack;
import org.graalvm.compiler.graph.NodeWorkList;
import org.graalvm.compiler.graph.Position;
import org.graalvm.compiler.graph.iterators.NodeIterable;
import org.graalvm.compiler.graph.spi.SimplifierTool;
import org.graalvm.compiler.nodes.AbstractBeginNode;
import org.graalvm.compiler.nodes.AbstractEndNode;
import org.graalvm.compiler.nodes.AbstractMergeNode;
import org.graalvm.compiler.nodes.ControlSplitNode;
import org.graalvm.compiler.nodes.FixedNode;
import org.graalvm.compiler.nodes.FixedWithNextNode;
import org.graalvm.compiler.nodes.FrameState;
import org.graalvm.compiler.nodes.GuardNode;
import org.graalvm.compiler.nodes.LoopBeginNode;
import org.graalvm.compiler.nodes.LoopEndNode;
import org.graalvm.compiler.nodes.LoopExitNode;
import org.graalvm.compiler.nodes.PhiNode;
import org.graalvm.compiler.nodes.PiNode;
import org.graalvm.compiler.nodes.ProxyNode;
import org.graalvm.compiler.nodes.StateSplit;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
import org.graalvm.compiler.nodes.spi.ArrayLengthProvider;
import org.graalvm.compiler.nodes.spi.LimitedValueProxy;
import org.graalvm.compiler.nodes.spi.LoweringProvider;
import org.graalvm.compiler.nodes.spi.ValueProxy;
import org.graalvm.compiler.options.Option;
import org.graalvm.compiler.options.OptionKey;
import org.graalvm.compiler.options.OptionType;
import org.graalvm.compiler.options.OptionValues;
import org.graalvm.util.EconomicMap;
import org.graalvm.util.EconomicSet;
import org.graalvm.util.Equivalence;
import org.graalvm.util.MapCursor;
import jdk.vm.ci.code.BailoutException;
import jdk.vm.ci.code.BytecodePosition;
import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.ConstantReflectionProvider;
import jdk.vm.ci.meta.MetaAccessProvider;
import jdk.vm.ci.meta.ResolvedJavaMethod;
public class GraphUtil {
public static class Options {
@Option(help = "Verify that there are no new unused nodes when performing killCFG", type = OptionType.Debug)//
public static final OptionKey<Boolean> VerifyKillCFGUnusedNodes = new OptionKey<>(false);
}
private static void killCFGInner(FixedNode node) {
EconomicSet<Node> markedNodes = EconomicSet.create();
EconomicMap<AbstractMergeNode, List<AbstractEndNode>> unmarkedMerges = EconomicMap.create();
// Detach this node from CFG
node.replaceAtPredecessor(null);
markFixedNodes(node, markedNodes, unmarkedMerges);
fixSurvivingAffectedMerges(markedNodes, unmarkedMerges);
Debug.dump(Debug.DETAILED_LEVEL, node.graph(), "After fixing merges (killCFG %s)", node);
// Mark non-fixed nodes
markUsages(markedNodes);
// Detach marked nodes from non-marked nodes
for (Node marked : markedNodes) {
for (Node input : marked.inputs()) {
if (!markedNodes.contains(input)) {
marked.replaceFirstInput(input, null);
tryKillUnused(input);
}
}
}
Debug.dump(Debug.VERY_DETAILED_LEVEL, node.graph(), "After disconnecting non-marked inputs (killCFG %s)", node);
// Kill marked nodes
for (Node marked : markedNodes) {
if (marked.isAlive()) {
marked.markDeleted();
}
}
}
private static void markFixedNodes(FixedNode node, EconomicSet<Node> markedNodes, EconomicMap<AbstractMergeNode, List<AbstractEndNode>> unmarkedMerges) {
NodeStack workStack = new NodeStack();
workStack.push(node);
while (!workStack.isEmpty()) {
Node fixedNode = workStack.pop();
markedNodes.add(fixedNode);
if (fixedNode instanceof AbstractMergeNode) {
unmarkedMerges.removeKey((AbstractMergeNode) fixedNode);
}
while (fixedNode instanceof FixedWithNextNode) {
fixedNode = ((FixedWithNextNode) fixedNode).next();
if (fixedNode != null) {
markedNodes.add(fixedNode);
}
}
if (fixedNode instanceof ControlSplitNode) {
for (Node successor : fixedNode.successors()) {
workStack.push(successor);
}
} else if (fixedNode instanceof AbstractEndNode) {
AbstractEndNode end = (AbstractEndNode) fixedNode;
AbstractMergeNode merge = end.merge();
if (merge != null) {
assert !markedNodes.contains(merge) || (merge instanceof LoopBeginNode && end instanceof LoopEndNode) : merge;
if (merge instanceof LoopBeginNode) {
if (end == ((LoopBeginNode) merge).forwardEnd()) {
workStack.push(merge);
continue;
}
if (markedNodes.contains(merge)) {
continue;
}
}
List<AbstractEndNode> endsSeen = unmarkedMerges.get(merge);
if (endsSeen == null) {
endsSeen = new ArrayList<>(merge.forwardEndCount());
unmarkedMerges.put(merge, endsSeen);
}
endsSeen.add(end);
if (!(end instanceof LoopEndNode) && endsSeen.size() == merge.forwardEndCount()) {
assert merge.forwardEnds().filter(n -> !markedNodes.contains(n)).isEmpty();
// all this merge's forward ends are marked: it needs to be killed
workStack.push(merge);
}
}
}
}
}
private static void fixSurvivingAffectedMerges(EconomicSet<Node> markedNodes, EconomicMap<AbstractMergeNode, List<AbstractEndNode>> unmarkedMerges) {
MapCursor<AbstractMergeNode, List<AbstractEndNode>> cursor = unmarkedMerges.getEntries();
while (cursor.advance()) {
AbstractMergeNode merge = cursor.getKey();
for (AbstractEndNode end : cursor.getValue()) {
merge.removeEnd(end);
}
if (merge.phiPredecessorCount() == 1) {
if (merge instanceof LoopBeginNode) {
LoopBeginNode loopBegin = (LoopBeginNode) merge;
assert merge.forwardEndCount() == 1;
for (LoopExitNode loopExit : loopBegin.loopExits().snapshot()) {
if (markedNodes.contains(loopExit)) {
/*
* disconnect from loop begin so that reduceDegenerateLoopBegin doesn't
* transform it into a new beginNode
*/
loopExit.replaceFirstInput(loopBegin, null);
}
}
merge.graph().reduceDegenerateLoopBegin(loopBegin);
} else {
merge.graph().reduceTrivialMerge(merge);
}
} else {
assert merge.phiPredecessorCount() > 1 : merge;
}
}
}
private static void markUsages(EconomicSet<Node> markedNodes) {
NodeStack workStack = new NodeStack(markedNodes.size() + 4);
for (Node marked : markedNodes) {
workStack.push(marked);
}
while (!workStack.isEmpty()) {
Node marked = workStack.pop();
for (Node usage : marked.usages()) {
if (!markedNodes.contains(usage)) {
workStack.push(usage);
markedNodes.add(usage);
}
}
}
}
@SuppressWarnings("try")
public static void killCFG(FixedNode node) {
try (Debug.Scope scope = Debug.scope("KillCFG", node)) {
EconomicSet<Node> unusedNodes = null;
EconomicSet<Node> unsafeNodes = null;
Graph.NodeEventScope nodeEventScope = null;
OptionValues options = node.getOptions();
if (Graph.Options.VerifyGraalGraphEdges.getValue(options)) {
unsafeNodes = collectUnsafeNodes(node.graph());
}
if (GraphUtil.Options.VerifyKillCFGUnusedNodes.getValue(options)) {
EconomicSet<Node> collectedUnusedNodes = unusedNodes = EconomicSet.create(Equivalence.IDENTITY);
nodeEventScope = node.graph().trackNodeEvents(new Graph.NodeEventListener() {
@Override
public void event(Graph.NodeEvent e, Node n) {
if (e == Graph.NodeEvent.ZERO_USAGES && isFloatingNode(n) && !(n instanceof GuardNode)) {
collectedUnusedNodes.add(n);
}
}
});
}
Debug.dump(Debug.VERY_DETAILED_LEVEL, node.graph(), "Before killCFG %s", node);
killCFGInner(node);
Debug.dump(Debug.VERY_DETAILED_LEVEL, node.graph(), "After killCFG %s", node);
if (Graph.Options.VerifyGraalGraphEdges.getValue(options)) {
EconomicSet<Node> newUnsafeNodes = collectUnsafeNodes(node.graph());
newUnsafeNodes.removeAll(unsafeNodes);
assert newUnsafeNodes.isEmpty() : "New unsafe nodes: " + newUnsafeNodes;
}
if (GraphUtil.Options.VerifyKillCFGUnusedNodes.getValue(options)) {
nodeEventScope.close();
Iterator<Node> iterator = unusedNodes.iterator();
while (iterator.hasNext()) {
Node curNode = iterator.next();
if (curNode.isDeleted()) {
iterator.remove();
}
}
assert unusedNodes.isEmpty() : "New unused nodes: " + unusedNodes;
}
} catch (Throwable t) {
throw Debug.handle(t);
}
}
/**
* Collects all node in the graph which have non-optional inputs that are null.
*/
private static EconomicSet<Node> collectUnsafeNodes(Graph graph) {
EconomicSet<Node> unsafeNodes = EconomicSet.create(Equivalence.IDENTITY);
for (Node n : graph.getNodes()) {
for (Position pos : n.inputPositions()) {
Node input = pos.get(n);
if (input == null) {
if (!pos.isInputOptional()) {
unsafeNodes.add(n);
}
}
}
}
return unsafeNodes;
}
public static boolean isFloatingNode(Node n) {
return !(n instanceof FixedNode);
}
private static boolean checkKill(Node node, boolean mayKillGuard) {
node.assertTrue(mayKillGuard || !(node instanceof GuardNode), "must not be a guard node %s", node);
node.assertTrue(node.isAlive(), "must be alive");
node.assertTrue(node.hasNoUsages(), "cannot kill node %s because of usages: %s", node, node.usages());
node.assertTrue(node.predecessor() == null, "cannot kill node %s because of predecessor: %s", node, node.predecessor());
return true;
}
public static void killWithUnusedFloatingInputs(Node node) {
killWithUnusedFloatingInputs(node, false);
}
public static void killWithUnusedFloatingInputs(Node node, boolean mayKillGuard) {
assert checkKill(node, mayKillGuard);
node.markDeleted();
outer: for (Node in : node.inputs()) {
if (in.isAlive()) {
in.removeUsage(node);
if (in.hasNoUsages()) {
node.maybeNotifyZeroUsages(in);
}
if (isFloatingNode(in)) {
if (in.hasNoUsages()) {
if (in instanceof GuardNode) {
// Guard nodes are only killed if their anchor dies.
} else {
killWithUnusedFloatingInputs(in);
}
} else if (in instanceof PhiNode) {
for (Node use : in.usages()) {
if (use != in) {
continue outer;
}
}
in.replaceAtUsages(null);
killWithUnusedFloatingInputs(in);
}
}
}
}
}
/**
* Removes all nodes created after the {@code mark}, assuming no "old" nodes point to "new"
* nodes.
*/
public static void removeNewNodes(Graph graph, Graph.Mark mark) {
assert checkNoOldToNewEdges(graph, mark);
for (Node n : graph.getNewNodes(mark)) {
n.markDeleted();
for (Node in : n.inputs()) {
in.removeUsage(n);
}
}
}
private static boolean checkNoOldToNewEdges(Graph graph, Graph.Mark mark) {
for (Node old : graph.getNodes()) {
if (graph.isNew(mark, old)) {
break;
}
for (Node n : old.successors()) {
assert !graph.isNew(mark, n) : old + " -> " + n;
}
for (Node n : old.inputs()) {
assert !graph.isNew(mark, n) : old + " -> " + n;
}
}
return true;
}
public static void removeFixedWithUnusedInputs(FixedWithNextNode fixed) {
if (fixed instanceof StateSplit) {
FrameState stateAfter = ((StateSplit) fixed).stateAfter();
if (stateAfter != null) {
((StateSplit) fixed).setStateAfter(null);
if (stateAfter.hasNoUsages()) {
killWithUnusedFloatingInputs(stateAfter);
}
}
}
unlinkFixedNode(fixed);
killWithUnusedFloatingInputs(fixed);
}
public static void unlinkFixedNode(FixedWithNextNode fixed) {
assert fixed.next() != null && fixed.predecessor() != null && fixed.isAlive() : fixed;
FixedNode next = fixed.next();
fixed.setNext(null);
fixed.replaceAtPredecessor(next);
}
public static void checkRedundantPhi(PhiNode phiNode) {
if (phiNode.isDeleted() || phiNode.valueCount() == 1) {
return;
}
ValueNode singleValue = phiNode.singleValueOrThis();
if (singleValue != phiNode) {
Collection<PhiNode> phiUsages = phiNode.usages().filter(PhiNode.class).snapshot();
Collection<ProxyNode> proxyUsages = phiNode.usages().filter(ProxyNode.class).snapshot();
phiNode.replaceAtUsagesAndDelete(singleValue);
for (PhiNode phi : phiUsages) {
checkRedundantPhi(phi);
}
for (ProxyNode proxy : proxyUsages) {
checkRedundantProxy(proxy);
}
}
}
public static void checkRedundantProxy(ProxyNode vpn) {
if (vpn.isDeleted()) {
return;
}
AbstractBeginNode proxyPoint = vpn.proxyPoint();
if (proxyPoint instanceof LoopExitNode) {
LoopExitNode exit = (LoopExitNode) proxyPoint;
LoopBeginNode loopBegin = exit.loopBegin();
Node vpnValue = vpn.value();
for (ValueNode v : loopBegin.stateAfter().values()) {
ValueNode v2 = v;
if (loopBegin.isPhiAtMerge(v2)) {
v2 = ((PhiNode) v2).valueAt(loopBegin.forwardEnd());
}
if (vpnValue == v2) {
Collection<PhiNode> phiUsages = vpn.usages().filter(PhiNode.class).snapshot();
Collection<ProxyNode> proxyUsages = vpn.usages().filter(ProxyNode.class).snapshot();
vpn.replaceAtUsagesAndDelete(vpnValue);
for (PhiNode phi : phiUsages) {
checkRedundantPhi(phi);
}
for (ProxyNode proxy : proxyUsages) {
checkRedundantProxy(proxy);
}
return;
}
}
}
}
/**
* Remove loop header without loop ends. This can happen with degenerated loops like this one:
*
* <pre>
* for (;;) {
* try {
* break;
* } catch (UnresolvedException iioe) {
* }
* }
* </pre>
*/
public static void normalizeLoops(StructuredGraph graph) {
boolean loopRemoved = false;
for (LoopBeginNode begin : graph.getNodes(LoopBeginNode.TYPE)) {
if (begin.loopEnds().isEmpty()) {
assert begin.forwardEndCount() == 1;
graph.reduceDegenerateLoopBegin(begin);
loopRemoved = true;
} else {
normalizeLoopBegin(begin);
}
}
if (loopRemoved) {
/*
* Removing a degenerated loop can make non-loop phi functions unnecessary. Therefore,
* we re-check all phi functions and remove redundant ones.
*/
for (Node node : graph.getNodes()) {
if (node instanceof PhiNode) {
checkRedundantPhi((PhiNode) node);
}
}
}
}
private static void normalizeLoopBegin(LoopBeginNode begin) {
// Delete unnecessary loop phi functions, i.e., phi functions where all inputs are either
// the same or the phi itself.
for (PhiNode phi : begin.phis().snapshot()) {
GraphUtil.checkRedundantPhi(phi);
}
for (LoopExitNode exit : begin.loopExits()) {
for (ProxyNode vpn : exit.proxies().snapshot()) {
GraphUtil.checkRedundantProxy(vpn);
}
}
}
/**
* Gets an approximate source code location for a node if possible.
*
* @return the StackTraceElements if an approximate source location is found, null otherwise
*/
public static StackTraceElement[] approxSourceStackTraceElement(Node node) {
NodeSourcePosition position = node.getNodeSourcePosition();
if (position != null) {
// use GraphBuilderConfiguration and enable trackNodeSourcePosition to get better source
// positions.
return approxSourceStackTraceElement(position);
}
ArrayList<StackTraceElement> elements = new ArrayList<>();
Node n = node;
while (n != null) {
if (n instanceof MethodCallTargetNode) {
elements.add(((MethodCallTargetNode) n).targetMethod().asStackTraceElement(-1));
n = ((MethodCallTargetNode) n).invoke().asNode();
}
if (n instanceof StateSplit) {
FrameState state = ((StateSplit) n).stateAfter();
elements.addAll(Arrays.asList(approxSourceStackTraceElement(state)));
break;
}
n = n.predecessor();
}
return elements.toArray(new StackTraceElement[elements.size()]);
}
/**
* Gets an approximate source code location for frame state.
*
* @return the StackTraceElements if an approximate source location is found, null otherwise
*/
public static StackTraceElement[] approxSourceStackTraceElement(FrameState frameState) {
ArrayList<StackTraceElement> elements = new ArrayList<>();
FrameState state = frameState;
while (state != null) {
Bytecode code = state.getCode();
if (code != null) {
elements.add(code.asStackTraceElement(state.bci - 1));
}
state = state.outerFrameState();
}
return elements.toArray(new StackTraceElement[0]);
}
/**
* Gets approximate stack trace elements for a bytecode position.
*/
public static StackTraceElement[] approxSourceStackTraceElement(BytecodePosition bytecodePosition) {
ArrayList<StackTraceElement> elements = new ArrayList<>();
BytecodePosition position = bytecodePosition;
while (position != null) {
ResolvedJavaMethod method = position.getMethod();
if (method != null) {
elements.add(method.asStackTraceElement(position.getBCI()));
}
position = position.getCaller();
}
return elements.toArray(new StackTraceElement[0]);
}
/**
* Gets an approximate source code location for a node, encoded as an exception, if possible.
*
* @return the exception with the location
*/
public static RuntimeException approxSourceException(Node node, Throwable cause) {
final StackTraceElement[] elements = approxSourceStackTraceElement(node);
return createBailoutException(cause == null ? "" : cause.getMessage(), cause, elements);
}
/**
* Creates a bailout exception with the given stack trace elements and message.
*
* @param message the message of the exception
* @param elements the stack trace elements
* @return the exception
*/
public static BailoutException createBailoutException(String message, Throwable cause, StackTraceElement[] elements) {
return SourceStackTraceBailoutException.create(cause, message, elements);
}
/**
* Gets an approximate source code location for a node if possible.
*
* @return a file name and source line number in stack trace format (e.g. "String.java:32") if
* an approximate source location is found, null otherwise
*/
public static String approxSourceLocation(Node node) {
StackTraceElement[] stackTraceElements = approxSourceStackTraceElement(node);
if (stackTraceElements != null && stackTraceElements.length > 0) {
StackTraceElement top = stackTraceElements[0];
if (top.getFileName() != null && top.getLineNumber() >= 0) {
return top.getFileName() + ":" + top.getLineNumber();
}
}
return null;
}
/**
* Returns a string representation of the given collection of objects.
*
* @param objects The {@link Iterable} that will be used to iterate over the objects.
* @return A string of the format "[a, b, ...]".
*/
public static String toString(Iterable<?> objects) {
StringBuilder str = new StringBuilder();
str.append("[");
for (Object o : objects) {
str.append(o).append(", ");
}
if (str.length() > 1) {
str.setLength(str.length() - 2);
}
str.append("]");
return str.toString();
}
/**
* Gets the original value by iterating through all {@link ValueProxy ValueProxies}.
*
* @param value the start value.
* @return the first non-proxy value encountered
*/
public static ValueNode unproxify(ValueNode value) {
if (value instanceof ValueProxy) {
return unproxify((ValueProxy) value);
} else {
return value;
}
}
/**
* Gets the original value by iterating through all {@link ValueProxy ValueProxies}.
*
* @param value the start value proxy.
* @return the first non-proxy value encountered
*/
public static ValueNode unproxify(ValueProxy value) {
if (value != null) {
ValueNode result = value.getOriginalNode();
while (result instanceof ValueProxy) {
result = ((ValueProxy) result).getOriginalNode();
}
return result;
} else {
return null;
}
}
public static ValueNode skipPi(ValueNode node) {
ValueNode n = node;
while (n instanceof PiNode) {
PiNode piNode = (PiNode) n;
n = piNode.getOriginalNode();
}
return n;
}
public static ValueNode skipPiWhileNonNull(ValueNode node) {
ValueNode n = node;
while (n instanceof PiNode) {
PiNode piNode = (PiNode) n;
ObjectStamp originalStamp = (ObjectStamp) piNode.getOriginalNode().stamp();
if (originalStamp.nonNull()) {
n = piNode.getOriginalNode();
} else {
break;
}
}
return n;
}
/**
* Looks for an {@link ArrayLengthProvider} while iterating through all {@link ValueProxy
* ValueProxies}.
*
* @param value The start value.
* @return The array length if one was found, or null otherwise.
*/
public static ValueNode arrayLength(ValueNode value) {
ValueNode current = value;
do {
if (current instanceof ArrayLengthProvider) {
ValueNode length = ((ArrayLengthProvider) current).length();
if (length != null) {
return length;
}
}
if (current instanceof ValueProxy) {
current = ((ValueProxy) current).getOriginalNode();
} else {
break;
}
} while (true);
return null;
}
/**
* Tries to find an original value of the given node by traversing through proxies and
* unambiguous phis. Note that this method will perform an exhaustive search through phis. It is
* intended to be used during graph building, when phi nodes aren't yet canonicalized.
*
* @param proxy The node whose original value should be determined.
*/
public static ValueNode originalValue(ValueNode proxy) {
ValueNode v = proxy;
do {
if (v instanceof LimitedValueProxy) {
v = ((LimitedValueProxy) v).getOriginalNode();
} else if (v instanceof PhiNode) {
PhiNode phiNode = (PhiNode) v;
v = phiNode.singleValueOrThis();
if (v == phiNode) {
v = null;
}
} else {
break;
}
} while (v != null);
if (v == null) {
v = new OriginalValueSearch(proxy).result;
}
return v;
}
public static boolean tryKillUnused(Node node) {
if (node.isAlive() && isFloatingNode(node) && node.hasNoUsages() && !(node instanceof GuardNode)) {
killWithUnusedFloatingInputs(node);
return true;
}
return false;
}
/**
* Exhaustive search for {@link GraphUtil#originalValue(ValueNode)} when a simple search fails.
* This can happen in the presence of complicated phi/proxy/phi constructs.
*/
static class OriginalValueSearch {
ValueNode result;
OriginalValueSearch(ValueNode proxy) {
NodeWorkList worklist = proxy.graph().createNodeWorkList();
worklist.add(proxy);
for (Node node : worklist) {
if (node instanceof LimitedValueProxy) {
ValueNode originalValue = ((LimitedValueProxy) node).getOriginalNode();
if (!process(originalValue, worklist)) {
return;
}
} else if (node instanceof PhiNode) {
for (Node value : ((PhiNode) node).values()) {
if (!process((ValueNode) value, worklist)) {
return;
}
}
} else {
if (!process((ValueNode) node, null)) {
return;
}
}
}
}
/**
* Process a node as part of this search.
*
* @param node the next node encountered in the search
* @param worklist if non-null, {@code node} will be added to this list. Otherwise,
* {@code node} is treated as a candidate result.
* @return true if the search should continue, false if a definitive {@link #result} has
* been found
*/
private boolean process(ValueNode node, NodeWorkList worklist) {
if (node.isAlive()) {
if (worklist == null) {
if (result == null) {
// Initial candidate result: continue search
result = node;
} else if (result != node) {
// Conflicts with existing candidate: stop search with null result
result = null;
return false;
}
} else {
worklist.add(node);
}
}
return true;
}
}
/**
* Returns an iterator that will return the given node followed by all its predecessors, up
* until the point where {@link Node#predecessor()} returns null.
*
* @param start the node at which to start iterating
*/
public static NodeIterable<FixedNode> predecessorIterable(final FixedNode start) {
return new NodeIterable<FixedNode>() {
@Override
public Iterator<FixedNode> iterator() {
return new Iterator<FixedNode>() {
public FixedNode current = start;
@Override
public boolean hasNext() {
return current != null;
}
@Override
public FixedNode next() {
try {
return current;
} finally {
current = (FixedNode) current.predecessor();
}
}
};
}
};
}
private static final class DefaultSimplifierTool implements SimplifierTool {
private final MetaAccessProvider metaAccess;
private final ConstantReflectionProvider constantReflection;
private final ConstantFieldProvider constantFieldProvider;
private final boolean canonicalizeReads;
private final Assumptions assumptions;
private final OptionValues options;
private final LoweringProvider loweringProvider;
DefaultSimplifierTool(MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider, boolean canonicalizeReads,
Assumptions assumptions, OptionValues options, LoweringProvider loweringProvider) {
this.metaAccess = metaAccess;
this.constantReflection = constantReflection;
this.constantFieldProvider = constantFieldProvider;
this.canonicalizeReads = canonicalizeReads;
this.assumptions = assumptions;
this.options = options;
this.loweringProvider = loweringProvider;
}
@Override
public MetaAccessProvider getMetaAccess() {
return metaAccess;
}
@Override
public ConstantReflectionProvider getConstantReflection() {
return constantReflection;
}
@Override
public ConstantFieldProvider getConstantFieldProvider() {
return constantFieldProvider;
}
@Override
public boolean canonicalizeReads() {
return canonicalizeReads;
}
@Override
public boolean allUsagesAvailable() {
return true;
}
@Override
public void deleteBranch(Node branch) {
FixedNode fixedBranch = (FixedNode) branch;
fixedBranch.predecessor().replaceFirstSuccessor(fixedBranch, null);
GraphUtil.killCFG(fixedBranch);
}
@Override
public void removeIfUnused(Node node) {
GraphUtil.tryKillUnused(node);
}
@Override
public void addToWorkList(Node node) {
}
@Override
public void addToWorkList(Iterable<? extends Node> nodes) {
}
@Override
public Assumptions getAssumptions() {
return assumptions;
}
@Override
public OptionValues getOptions() {
return options;
}
@Override
public Integer smallestCompareWidth() {
if (loweringProvider != null) {
return loweringProvider.smallestCompareWidth();
} else {
return null;
}
}
}
public static SimplifierTool getDefaultSimplifier(MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider,
boolean canonicalizeReads, Assumptions assumptions, OptionValues options) {
return getDefaultSimplifier(metaAccess, constantReflection, constantFieldProvider, canonicalizeReads, assumptions, options, null);
}
public static SimplifierTool getDefaultSimplifier(MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider,
boolean canonicalizeReads, Assumptions assumptions, OptionValues options, LoweringProvider loweringProvider) {
return new DefaultSimplifierTool(metaAccess, constantReflection, constantFieldProvider, canonicalizeReads, assumptions, options, loweringProvider);
}
public static Constant foldIfConstantAndRemove(ValueNode node, ValueNode constant) {
assert node.inputs().contains(constant);
if (constant.isConstant()) {
node.replaceFirstInput(constant, null);
Constant result = constant.asConstant();
tryKillUnused(constant);
return result;
}
return null;
}
}