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fernflower/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/FlattenStatementsHelper.java

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// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package org.jetbrains.java.decompiler.modules.decompiler.sforms;
import org.jetbrains.java.decompiler.modules.decompiler.StatEdge;
import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
import org.jetbrains.java.decompiler.modules.decompiler.stats.*;
import java.util.*;
import java.util.Map.Entry;
public class FlattenStatementsHelper {
// statement.id, node.id(direct), node.id(continue)
private final Map<Integer, String[]> mapDestinationNodes = new HashMap<>();
// node.id(source), statement.id(destination), edge type
private final List<Edge> listEdges = new ArrayList<>();
// node.id(exit), [node.id(source), statement.id(destination)]
private final Map<String, List<String[]>> mapShortRangeFinallyPathIds = new HashMap<>();
// node.id(exit), [node.id(source), statement.id(destination)]
private final Map<String, List<String[]>> mapLongRangeFinallyPathIds = new HashMap<>();
// positive if branches
private final Map<String, Integer> mapPosIfBranch = new HashMap<>();
private DirectGraph graph;
private RootStatement root;
public DirectGraph buildDirectGraph(RootStatement root) {
this.root = root;
graph = new DirectGraph();
flattenStatement();
// dummy exit node
Statement dummyexit = root.getDummyExit();
DirectNode node = new DirectNode(DirectNode.NODE_DIRECT, dummyexit, dummyexit.id.toString());
node.exprents = new ArrayList<>();
graph.nodes.addWithKey(node, node.id);
mapDestinationNodes.put(dummyexit.id, new String[]{node.id, null});
setEdges();
graph.first = graph.nodes.getWithKey(mapDestinationNodes.get(root.id)[0]);
graph.sortReversePostOrder();
return graph;
}
private void flattenStatement() {
class StatementStackEntry {
public final Statement statement;
public final LinkedList<StackEntry> stackFinally;
public final List<Exprent> tailExprents;
public int statementIndex;
public int edgeIndex;
public List<StatEdge> succEdges;
StatementStackEntry(Statement statement, LinkedList<StackEntry> stackFinally, List<Exprent> tailExprents) {
this.statement = statement;
this.stackFinally = stackFinally;
this.tailExprents = tailExprents;
}
}
LinkedList<StatementStackEntry> lstStackStatements = new LinkedList<>();
lstStackStatements.add(new StatementStackEntry(root, new LinkedList<>(), null));
mainloop:
while (!lstStackStatements.isEmpty()) {
StatementStackEntry statEntry = lstStackStatements.removeFirst();
Statement stat = statEntry.statement;
LinkedList<StackEntry> stackFinally = statEntry.stackFinally;
int statementBreakIndex = statEntry.statementIndex;
DirectNode node, nd;
List<StatEdge> lstSuccEdges = new ArrayList<>();
DirectNode sourcenode = null;
if (statEntry.succEdges == null) {
switch (stat.type) {
case Statement.TYPE_BASICBLOCK:
node = new DirectNode(DirectNode.NODE_DIRECT, stat, (BasicBlockStatement)stat);
if (stat.getExprents() != null) {
node.exprents = stat.getExprents();
}
graph.nodes.putWithKey(node, node.id);
mapDestinationNodes.put(stat.id, new String[]{node.id, null});
lstSuccEdges.addAll(stat.getSuccessorEdges(Statement.STATEDGE_DIRECT_ALL));
sourcenode = node;
List<Exprent> tailExprentList = statEntry.tailExprents;
if (tailExprentList != null) {
DirectNode tail = new DirectNode(DirectNode.NODE_TAIL, stat, stat.id + "_tail");
tail.exprents = tailExprentList;
graph.nodes.putWithKey(tail, tail.id);
mapDestinationNodes.put(-stat.id, new String[]{tail.id, null});
listEdges.add(new Edge(node.id, -stat.id, StatEdge.TYPE_REGULAR));
sourcenode = tail;
}
// 'if' statement: record positive branch
if (stat.getLastBasicType() == Statement.LASTBASICTYPE_IF) {
mapPosIfBranch.put(sourcenode.id, lstSuccEdges.get(0).getDestination().id);
}
break;
case Statement.TYPE_CATCHALL:
case Statement.TYPE_TRYCATCH:
DirectNode firstnd = new DirectNode(DirectNode.NODE_TRY, stat, stat.id + "_try");
mapDestinationNodes.put(stat.id, new String[]{firstnd.id, null});
graph.nodes.putWithKey(firstnd, firstnd.id);
LinkedList<StatementStackEntry> lst = new LinkedList<>();
for (Statement st : stat.getStats()) {
listEdges.add(new Edge(firstnd.id, st.id, StatEdge.TYPE_REGULAR));
LinkedList<StackEntry> stack = stackFinally;
if (stat.type == Statement.TYPE_CATCHALL && ((CatchAllStatement)stat).isFinally()) {
stack = new LinkedList<>(stackFinally);
if (st == stat.getFirst()) { // catch head
stack.add(new StackEntry((CatchAllStatement)stat, Boolean.FALSE));
}
else { // handler
stack.add(new StackEntry((CatchAllStatement)stat, Boolean.TRUE, StatEdge.TYPE_BREAK,
root.getDummyExit(), st, st, firstnd, firstnd, true));
}
}
lst.add(new StatementStackEntry(st, stack, null));
}
lstStackStatements.addAll(0, lst);
break;
case Statement.TYPE_DO:
if (statementBreakIndex == 0) {
statEntry.statementIndex = 1;
lstStackStatements.addFirst(statEntry);
lstStackStatements.addFirst(new StatementStackEntry(stat.getFirst(), stackFinally, null));
continue mainloop;
}
nd = graph.nodes.getWithKey(mapDestinationNodes.get(stat.getFirst().id)[0]);
DoStatement dostat = (DoStatement)stat;
int looptype = dostat.getLooptype();
if (looptype == DoStatement.LOOP_DO) {
mapDestinationNodes.put(stat.id, new String[]{nd.id, nd.id});
break;
}
lstSuccEdges.add(stat.getSuccessorEdges(Statement.STATEDGE_DIRECT_ALL).get(0)); // exactly one edge
switch (looptype) {
case DoStatement.LOOP_WHILE:
case DoStatement.LOOP_DOWHILE:
node = new DirectNode(DirectNode.NODE_CONDITION, stat, stat.id + "_cond");
node.exprents = dostat.getConditionExprentList();
graph.nodes.putWithKey(node, node.id);
listEdges.add(new Edge(node.id, stat.getFirst().id, StatEdge.TYPE_REGULAR));
if (looptype == DoStatement.LOOP_WHILE) {
mapDestinationNodes.put(stat.id, new String[]{node.id, node.id});
}
else {
mapDestinationNodes.put(stat.id, new String[]{nd.id, node.id});
boolean found = false;
for (Edge edge : listEdges) {
if (edge.statid.equals(stat.id) && edge.edgetype == StatEdge.TYPE_CONTINUE) {
found = true;
break;
}
}
if (!found) {
listEdges.add(new Edge(nd.id, stat.id, StatEdge.TYPE_CONTINUE));
}
}
sourcenode = node;
break;
case DoStatement.LOOP_FOR:
DirectNode nodeinit = new DirectNode(DirectNode.NODE_INIT, stat, stat.id + "_init");
if (dostat.getInitExprent() != null) {
nodeinit.exprents = dostat.getInitExprentList();
}
graph.nodes.putWithKey(nodeinit, nodeinit.id);
DirectNode nodecond = new DirectNode(DirectNode.NODE_CONDITION, stat, stat.id + "_cond");
nodecond.exprents = dostat.getConditionExprentList();
graph.nodes.putWithKey(nodecond, nodecond.id);
DirectNode nodeinc = new DirectNode(DirectNode.NODE_INCREMENT, stat, stat.id + "_inc");
nodeinc.exprents = dostat.getIncExprentList();
graph.nodes.putWithKey(nodeinc, nodeinc.id);
mapDestinationNodes.put(stat.id, new String[]{nodeinit.id, nodeinc.id});
mapDestinationNodes.put(-stat.id, new String[]{nodecond.id, null});
listEdges.add(new Edge(nodecond.id, stat.getFirst().id, StatEdge.TYPE_REGULAR));
listEdges.add(new Edge(nodeinit.id, -stat.id, StatEdge.TYPE_REGULAR));
listEdges.add(new Edge(nodeinc.id, -stat.id, StatEdge.TYPE_REGULAR));
boolean found = false;
for (Edge edge : listEdges) {
if (edge.statid.equals(stat.id) && edge.edgetype == StatEdge.TYPE_CONTINUE) {
found = true;
break;
}
}
if (!found) {
listEdges.add(new Edge(nd.id, stat.id, StatEdge.TYPE_CONTINUE));
}
sourcenode = nodecond;
}
break;
case Statement.TYPE_SYNCRONIZED:
case Statement.TYPE_SWITCH:
case Statement.TYPE_IF:
case Statement.TYPE_SEQUENCE:
case Statement.TYPE_ROOT:
int statsize = stat.getStats().size();
if (stat.type == Statement.TYPE_SYNCRONIZED) {
statsize = 2; // exclude the handler if synchronized
}
if (statementBreakIndex <= statsize) {
List<Exprent> tailexprlst = null;
switch (stat.type) {
case Statement.TYPE_SYNCRONIZED:
tailexprlst = ((SynchronizedStatement)stat).getHeadexprentList();
break;
case Statement.TYPE_SWITCH:
tailexprlst = ((SwitchStatement)stat).getHeadexprentList();
break;
case Statement.TYPE_IF:
tailexprlst = ((IfStatement)stat).getHeadexprentList();
}
for (int i = statementBreakIndex; i < statsize; i++) {
statEntry.statementIndex = i + 1;
lstStackStatements.addFirst(statEntry);
lstStackStatements.addFirst(
new StatementStackEntry(stat.getStats().get(i), stackFinally,
(i == 0 && tailexprlst != null && tailexprlst.get(0) != null) ? tailexprlst : null));
continue mainloop;
}
node = graph.nodes.getWithKey(mapDestinationNodes.get(stat.getFirst().id)[0]);
mapDestinationNodes.put(stat.id, new String[]{node.id, null});
if (stat.type == Statement.TYPE_IF && ((IfStatement)stat).iftype == IfStatement.IFTYPE_IF) {
lstSuccEdges.add(stat.getSuccessorEdges(Statement.STATEDGE_DIRECT_ALL).get(0)); // exactly one edge
sourcenode = tailexprlst.get(0) == null ? node : graph.nodes.getWithKey(node.id + "_tail");
}
}
}
}
// no successor edges
if (sourcenode != null) {
if (statEntry.succEdges != null) {
lstSuccEdges = statEntry.succEdges;
}
for (int edgeindex = statEntry.edgeIndex; edgeindex < lstSuccEdges.size(); edgeindex++) {
StatEdge edge = lstSuccEdges.get(edgeindex);
LinkedList<StackEntry> stack = new LinkedList<>(stackFinally);
int edgetype = edge.getType();
Statement destination = edge.getDestination();
DirectNode finallyShortRangeSource = sourcenode;
DirectNode finallyLongRangeSource = sourcenode;
Statement finallyShortRangeEntry = null;
Statement finallyLongRangeEntry = null;
boolean isFinallyMonitorExceptionPath = false;
boolean isFinallyExit = false;
while (true) {
StackEntry entry = null;
if (!stack.isEmpty()) {
entry = stack.getLast();
}
boolean created = true;
if (entry == null) {
saveEdge(sourcenode, destination, edgetype, isFinallyExit ? finallyShortRangeSource : null, finallyLongRangeSource,
finallyShortRangeEntry, finallyLongRangeEntry, isFinallyMonitorExceptionPath);
}
else {
CatchAllStatement catchall = entry.catchstatement;
if (entry.state) { // finally handler statement
if (edgetype == StatEdge.TYPE_FINALLYEXIT) {
stack.removeLast();
destination = entry.destination;
edgetype = entry.edgetype;
finallyShortRangeSource = entry.finallyShortRangeSource;
finallyLongRangeSource = entry.finallyLongRangeSource;
finallyShortRangeEntry = entry.finallyShortRangeEntry;
finallyLongRangeEntry = entry.finallyLongRangeEntry;
isFinallyExit = true;
isFinallyMonitorExceptionPath = (catchall.getMonitor() != null) & entry.isFinallyExceptionPath;
created = false;
}
else {
if (!catchall.containsStatementStrict(destination)) {
stack.removeLast();
created = false;
}
else {
saveEdge(sourcenode, destination, edgetype, isFinallyExit ? finallyShortRangeSource : null, finallyLongRangeSource,
finallyShortRangeEntry, finallyLongRangeEntry, isFinallyMonitorExceptionPath);
}
}
}
else { // finally protected try statement
if (!catchall.containsStatementStrict(destination)) {
saveEdge(sourcenode, catchall.getHandler(), StatEdge.TYPE_REGULAR, isFinallyExit ? finallyShortRangeSource : null,
finallyLongRangeSource, finallyShortRangeEntry, finallyLongRangeEntry, isFinallyMonitorExceptionPath);
stack.removeLast();
stack.add(new StackEntry(catchall, Boolean.TRUE, edgetype, destination, catchall.getHandler(),
finallyLongRangeEntry == null ? catchall.getHandler() : finallyLongRangeEntry,
sourcenode, finallyLongRangeSource, false));
statEntry.edgeIndex = edgeindex + 1;
statEntry.succEdges = lstSuccEdges;
lstStackStatements.addFirst(statEntry);
lstStackStatements.addFirst(new StatementStackEntry(catchall.getHandler(), stack, null));
continue mainloop;
}
else {
saveEdge(sourcenode, destination, edgetype, isFinallyExit ? finallyShortRangeSource : null, finallyLongRangeSource,
finallyShortRangeEntry, finallyLongRangeEntry, isFinallyMonitorExceptionPath);
}
}
}
if (created) {
break;
}
}
}
}
}
}
private void saveEdge(DirectNode sourcenode,
Statement destination,
int edgetype,
DirectNode finallyShortRangeSource,
DirectNode finallyLongRangeSource,
Statement finallyShortRangeEntry,
Statement finallyLongRangeEntry,
boolean isFinallyMonitorExceptionPath) {
if (edgetype != StatEdge.TYPE_FINALLYEXIT) {
listEdges.add(new Edge(sourcenode.id, destination.id, edgetype));
}
if (finallyShortRangeSource != null) {
boolean isContinueEdge = (edgetype == StatEdge.TYPE_CONTINUE);
mapShortRangeFinallyPathIds.computeIfAbsent(sourcenode.id, k -> new ArrayList<>()).add(new String[]{
finallyShortRangeSource.id,
destination.id.toString(),
finallyShortRangeEntry.id.toString(),
isFinallyMonitorExceptionPath ? "1" : null,
isContinueEdge ? "1" : null});
mapLongRangeFinallyPathIds.computeIfAbsent(sourcenode.id, k -> new ArrayList<>()).add(new String[]{
finallyLongRangeSource.id,
destination.id.toString(),
finallyLongRangeEntry.id.toString(),
isContinueEdge ? "1" : null});
}
}
private void setEdges() {
for (Edge edge : listEdges) {
String sourceid = edge.sourceid;
Integer statid = edge.statid;
DirectNode source = graph.nodes.getWithKey(sourceid);
DirectNode dest = graph.nodes.getWithKey(mapDestinationNodes.get(statid)[edge.edgetype == StatEdge.TYPE_CONTINUE ? 1 : 0]);
if (!source.succs.contains(dest)) {
source.succs.add(dest);
}
if (!dest.preds.contains(source)) {
dest.preds.add(source);
}
if (mapPosIfBranch.containsKey(sourceid) && !statid.equals(mapPosIfBranch.get(sourceid))) {
graph.mapNegIfBranch.put(sourceid, dest.id);
}
}
for (int i = 0; i < 2; i++) {
for (Entry<String, List<String[]>> ent : (i == 0 ? mapShortRangeFinallyPathIds : mapLongRangeFinallyPathIds).entrySet()) {
List<FinallyPathWrapper> newLst = new ArrayList<>();
List<String[]> lst = ent.getValue();
for (String[] arr : lst) {
boolean isContinueEdge = arr[i == 0 ? 4 : 3] != null;
DirectNode dest = graph.nodes.getWithKey(mapDestinationNodes.get(Integer.parseInt(arr[1]))[isContinueEdge ? 1 : 0]);
DirectNode enter = graph.nodes.getWithKey(mapDestinationNodes.get(Integer.parseInt(arr[2]))[0]);
newLst.add(new FinallyPathWrapper(arr[0], dest.id, enter.id));
if (i == 0 && arr[3] != null) {
graph.mapFinallyMonitorExceptionPathExits.put(ent.getKey(), dest.id);
}
}
if (!newLst.isEmpty()) {
(i == 0 ? graph.mapShortRangeFinallyPaths : graph.mapLongRangeFinallyPaths).put(ent.getKey(),
new ArrayList<>(
new HashSet<>(newLst)));
}
}
}
}
public Map<Integer, String[]> getMapDestinationNodes() {
return mapDestinationNodes;
}
public static final class FinallyPathWrapper {
public final String source;
public final String destination;
public final String entry;
private FinallyPathWrapper(String source, String destination, String entry) {
this.source = source;
this.destination = destination;
this.entry = entry;
}
@Override
public boolean equals(Object o) {
if (o == this) return true;
if (!(o instanceof FinallyPathWrapper)) return false;
FinallyPathWrapper fpw = (FinallyPathWrapper)o;
return (source + ":" + destination + ":" + entry).equals(fpw.source + ":" + fpw.destination + ":" + fpw.entry);
}
@Override
public int hashCode() {
return (source + ":" + destination + ":" + entry).hashCode();
}
@Override
public String toString() {
return source + "->(" + entry + ")->" + destination;
}
}
private static class StackEntry {
public final CatchAllStatement catchstatement;
public final boolean state;
public final int edgetype;
public final boolean isFinallyExceptionPath;
public final Statement destination;
public final Statement finallyShortRangeEntry;
public final Statement finallyLongRangeEntry;
public final DirectNode finallyShortRangeSource;
public final DirectNode finallyLongRangeSource;
StackEntry(CatchAllStatement catchstatement,
boolean state,
int edgetype,
Statement destination,
Statement finallyShortRangeEntry,
Statement finallyLongRangeEntry,
DirectNode finallyShortRangeSource,
DirectNode finallyLongRangeSource,
boolean isFinallyExceptionPath) {
this.catchstatement = catchstatement;
this.state = state;
this.edgetype = edgetype;
this.isFinallyExceptionPath = isFinallyExceptionPath;
this.destination = destination;
this.finallyShortRangeEntry = finallyShortRangeEntry;
this.finallyLongRangeEntry = finallyLongRangeEntry;
this.finallyShortRangeSource = finallyShortRangeSource;
this.finallyLongRangeSource = finallyLongRangeSource;
}
StackEntry(CatchAllStatement catchstatement, boolean state) {
this(catchstatement, state, -1, null, null, null, null, null, false);
}
}
private static class Edge {
public final String sourceid;
public final Integer statid;
public final int edgetype;
Edge(String sourceid, Integer statid, int edgetype) {
this.sourceid = sourceid;
this.statid = statid;
this.edgetype = edgetype;
}
}
}