Improve loop reconstruction

Author: emmanue1

src/main/java/org/jd/core/v1/service/converter/classfiletojavasyntax/util/ControlFlowGraphReducer.java

@@ -8,6 +8,7 @@
 package org.jd.core.v1.service.converter.classfiletojavasyntax.util;
 
 import org.jd.core.v1.model.classfile.attribute.AttributeCode;
+import org.jd.core.v1.model.javasyntax.expression.Expression;
 import org.jd.core.v1.service.converter.classfiletojavasyntax.model.cfg.BasicBlock;
 import org.jd.core.v1.service.converter.classfiletojavasyntax.model.cfg.ControlFlowGraph;
 
@@ -1260,31 +1261,41 @@ protected static void createContinueLoop(BitSet visited, BasicBlock basicBlock)
 
     protected static void createContinueLoop(BitSet visited, BasicBlock basicBlock, BasicBlock subBasicBlock) {
         if (subBasicBlock != null) {
-            if ((subBasicBlock.getPredecessors().size() > 1) && (basicBlock.getFromOffset() < subBasicBlock.getFromOffset()) && (basicBlock.getFirstLineNumber() > subBasicBlock.getFirstLineNumber())) {
-                Set<BasicBlock> predecessors = subBasicBlock.getPredecessors();
-                Iterator<BasicBlock> iterator = predecessors.iterator();
-                BasicBlock lastPredecessor = iterator.next();
-
-                if (lastPredecessor.getType() != TYPE_GOTO_IN_TERNARY_OPERATOR) {
-                    while (iterator.hasNext()) {
-                        BasicBlock predecessor = iterator.next();
-                        if (predecessor.getType() == TYPE_GOTO_IN_TERNARY_OPERATOR) {
-                            lastPredecessor = null;
-                            break;
-                        }
-                        if (lastPredecessor.getFromOffset() < predecessor.getFromOffset()) {
-                            lastPredecessor = predecessor;
-                        }
-                    }
+            if ((subBasicBlock.getPredecessors().size() > 1) && (basicBlock.getFromOffset() < subBasicBlock.getFromOffset())) {
+                boolean condition;
+
+                if (basicBlock.getFirstLineNumber() == Expression.UNKNOWN_LINE_NUMBER) {
+                    condition = subBasicBlock.matchType(GROUP_SINGLE_SUCCESSOR) && (subBasicBlock.getNext().getType() == TYPE_LOOP_START);
+                } else {
+                    condition = (basicBlock.getFirstLineNumber() > subBasicBlock.getFirstLineNumber());
+                }
 
-                    if (lastPredecessor != null) {
-                        iterator = predecessors.iterator();
+                if (condition) {
+                    Set<BasicBlock> predecessors = subBasicBlock.getPredecessors();
+                    Iterator<BasicBlock> iterator = predecessors.iterator();
+                    BasicBlock lastPredecessor = iterator.next();
 
+                    if (lastPredecessor.getType() != TYPE_GOTO_IN_TERNARY_OPERATOR) {
                         while (iterator.hasNext()) {
                             BasicBlock predecessor = iterator.next();
-                            if (predecessor != lastPredecessor) {
-                                iterator.remove();
-                                predecessor.replace(subBasicBlock, LOOP_CONTINUE);
+                            if (predecessor.getType() == TYPE_GOTO_IN_TERNARY_OPERATOR) {
+                                lastPredecessor = null;
+                                break;
+                            }
+                            if (lastPredecessor.getFromOffset() < predecessor.getFromOffset()) {
+                                lastPredecessor = predecessor;
+                            }
+                        }
+
+                        if (lastPredecessor != null) {
+                            iterator = predecessors.iterator();
+
+                            while (iterator.hasNext()) {
+                                BasicBlock predecessor = iterator.next();
+                                if (predecessor != lastPredecessor) {
+                                    iterator.remove();
+                                    predecessor.replace(subBasicBlock, LOOP_CONTINUE);
+                                }
                             }
                         }
                     }

src/main/java/org/jd/core/v1/service/converter/classfiletojavasyntax/util/LoopStatementMaker.java

@@ -17,6 +17,7 @@
 import org.jd.core.v1.service.converter.classfiletojavasyntax.model.javasyntax.statement.ClassFileForStatement;
 import org.jd.core.v1.service.converter.classfiletojavasyntax.model.localvariable.AbstractLocalVariable;
 import org.jd.core.v1.service.converter.classfiletojavasyntax.visitor.SearchFirstLineNumberVisitor;
+import org.jd.core.v1.service.converter.classfiletojavasyntax.visitor.SearchLocalVariableReferenceVisitor;
 
 import java.util.Collections;
 import java.util.Iterator;
@@ -567,7 +568,7 @@ protected static Statement makeForEachList(LocalVariableMaker localVariableMaker
 
         boe = (BinaryOperatorExpression)es.getExpression();
 
-        if ((boe == null) || (boe.getLeftExpression().getClass() != ClassFileLocalVariableReferenceExpression.class)) {
+        if (boe.getLeftExpression().getClass() != ClassFileLocalVariableReferenceExpression.class) {
             return null;
         }
 
@@ -589,15 +590,23 @@ protected static Statement makeForEachList(LocalVariableMaker localVariableMaker
             return null;
         }
 
+        // Check if 'i$' is not used in sub-statements
+        SearchLocalVariableReferenceVisitor visitor = new SearchLocalVariableReferenceVisitor(syntheticIterator);
+
+        for (int i=1, len=subStatements.size(); i<len; i++) {
+            subStatements.get(i).accept(visitor);
+        }
+
+        if (visitor.containsReference()) {
+            return null;
+        }
+
         // Found
         AbstractLocalVariable item = ((ClassFileLocalVariableReferenceExpression)boe.getLeftExpression()).getLocalVariable();
 
         statements.removeLast();
-
         subStatements.remove(0);
-
         item.setDeclared(true);
-
         localVariableMaker.removeLocalVariable(syntheticIterator);
 
         return new ClassFileForEachStatement(item, list, subStatements);

src/main/java/org/jd/core/v1/service/converter/classfiletojavasyntax/visitor/SearchLocalVariableReferenceVisitor.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2008-2019 Emmanuel Dupuy.
+ * This project is distributed under the GPLv3 license.
+ * This is a Copyleft license that gives the user the right to use,
+ * copy and modify the code freely for non-commercial purposes.
+ */
+
+package org.jd.core.v1.service.converter.classfiletojavasyntax.visitor;
+
+import org.jd.core.v1.model.javasyntax.AbstractJavaSyntaxVisitor;
+import org.jd.core.v1.model.javasyntax.expression.LocalVariableReferenceExpression;
+import org.jd.core.v1.service.converter.classfiletojavasyntax.model.javasyntax.expression.ClassFileLocalVariableReferenceExpression;
+import org.jd.core.v1.service.converter.classfiletojavasyntax.model.localvariable.AbstractLocalVariable;
+
+public class SearchLocalVariableReferenceVisitor extends AbstractJavaSyntaxVisitor {
+    protected int index;
+    protected boolean found;
+
+    public SearchLocalVariableReferenceVisitor(AbstractLocalVariable alv) {
+        this.index = alv.getIndex();
+        this.found = false;
+    }
+
+    public boolean containsReference() {
+        return found;
+    }
+
+    @Override
+    public void visit(LocalVariableReferenceExpression expression) {
+        ClassFileLocalVariableReferenceExpression referenceExpression = (ClassFileLocalVariableReferenceExpression)expression;
+        found |= referenceExpression.getLocalVariable().getIndex() == index;
+    }
+}