Fix incorrect SSAU in empty while loops, fix edges being removed from extracted loops

Author: jaskarth

src/org/jetbrains/java/decompiler/modules/decompiler/LoopExtractHelper.java

@@ -6,6 +6,7 @@
 import org.jetbrains.java.decompiler.modules.decompiler.exps.IfExprent;
 import org.jetbrains.java.decompiler.modules.decompiler.stats.*;
 import org.jetbrains.java.decompiler.modules.decompiler.stats.Statement.EdgeDirection;
+import org.jetbrains.java.decompiler.util.DotExporter;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -53,6 +54,7 @@ private static int extractLoopsRec(Statement stat) {
 
     if (stat instanceof DoStatement) {
       if (extractLoop((DoStatement)stat)) {
+        ValidationHelper.validateStatement(stat.getTopParent());
         return 2;
       }
     }
@@ -195,7 +197,8 @@ private static boolean extractFirstIf(DoStatement stat, List<Statement> stats) {
                 extractIfBlockIntoLoop(stat, firstif, check.getSuccessorEdges(StatEdge.TYPE_REGULAR).get(0).getDestination());
 
                 if (newDest) {
-                  removeFrom.removeSuccessor(continues.get(0));
+                  // TODO: is this correct?
+//                  removeFrom.removeSuccessor(continues.get(0));
                 }
 
                 return true;
@@ -299,9 +302,9 @@ private static void extractIfBlockIntoLoop(DoStatement loop, IfStatement ifStat,
     loop.addLabeledEdge(ifedge);
     ifStat.setIfEdge(ifedge);
 
-    SequenceStatement block = new SequenceStatement(Arrays.asList(ifStat, target));
-    ifStat.replaceWith( block);
-    block.setAllParent();
+    SequenceStatement seq = new SequenceStatement(Arrays.asList(ifStat, target));
+    ifStat.replaceWith(seq);
+    seq.setAllParent();
 
     ifStat.addSuccessor(new StatEdge(StatEdge.TYPE_REGULAR, ifStat, target));
 

src/org/jetbrains/java/decompiler/modules/decompiler/MergeHelper.java

@@ -210,6 +210,8 @@ protected static boolean matchWhile(DoStatement stat) {
               if (firstif == stat.getFirst()) {
                 BasicBlockStatement bstat = BasicBlockStatement.create();
                 stat.replaceStatement(firstif, bstat);
+                // We destroyed the loop body, but now we need to add a continue edge to make sure the empty body stays correct
+                bstat.addSuccessor(new StatEdge(StatEdge.TYPE_CONTINUE, bstat, stat, stat));
               }
               else {
                 // precondition: sequence must contain more than one statement!

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -672,7 +672,6 @@ private void registerDefault() {
     // TODO: Param type information is lost for lambdas where a more specific type is not required by the context
     register(JAVA_8, "TestLambdaParamTypes");
     register(JAVA_8, "TestGenericComparison");
-    // TODO: Can't inline field initializer for a final field that depends on initialization in a static call
     register(JAVA_8, "TestStaticBlockFinalField");
     register(JAVA_8, "TestWhileLambda");
     register(JAVA_8, "TestTrySplit");

testData/results/pkg/TestAssignmentInDoWhile.dec

@@ -27,7 +27,7 @@ public class TestAssignmentInDoWhile {
       int[] array = new int[100];// 29
       int x = 3;// 31
 
-      while (x < 50 && (x = x + array[x]) < 100) {// 33 38
+      while (x < 50 && (x += array[x]) < 100) {// 33 38
       }
 
       System.out.println("Hi");// 39
@@ -37,7 +37,7 @@ public class TestAssignmentInDoWhile {
       int[] array = new int[100];// 43
       int x = 3;// 45
 
-      while (x < 50 && (x = x + (array[x] & 7)) < 100) {// 47 52
+      while (x < 50 && (x += array[x] & 7) < 100) {// 47 52
       }
 
       System.out.println("Hi");// 53
@@ -47,7 +47,7 @@ public class TestAssignmentInDoWhile {
       int[] array = new int[100];// 57
       int x = 3;// 59
 
-      while (x < 50 && (x = x + array[x]) < 100 && x > 10) {// 61 66
+      while (x < 50 && (x += array[x]) < 100 && x > 10) {// 61 66
       }
 
       System.out.println("Hi");// 67
@@ -57,7 +57,7 @@ public class TestAssignmentInDoWhile {
       int[] array = new int[100];// 71
       int x = 3;// 73
 
-      while (x < 50 && ((x = x + array[x]) < 100 || x > 10)) {// 75 80
+      while (x < 50 && ((x += array[x]) < 100 || x > 10)) {// 75 80
       }
 
       System.out.println("Hi");// 81
@@ -134,11 +134,9 @@ class 'pkg/TestAssignmentInDoWhile' {
       a      29
       b      29
       c      29
-      d      29
       e      29
       f      29
       10      29
-      11      29
       13      29
       14      29
       15      29
@@ -168,14 +166,12 @@ class 'pkg/TestAssignmentInDoWhile' {
       a      39
       b      39
       c      39
-      d      39
       e      39
       f      39
       10      39
       11      39
       12      39
       13      39
-      14      39
       16      39
       17      39
       18      39
@@ -205,11 +201,9 @@ class 'pkg/TestAssignmentInDoWhile' {
       a      49
       b      49
       c      49
-      d      49
       e      49
       f      49
       10      49
-      11      49
       13      49
       14      49
       15      49
@@ -245,11 +239,9 @@ class 'pkg/TestAssignmentInDoWhile' {
       a      59
       b      59
       c      59
-      d      59
       e      59
       f      59
       10      59
-      11      59
       13      59
       14      59
       15      59
@@ -308,4 +300,4 @@ Lines mapping:
 75 <-> 60
 80 <-> 60
 81 <-> 63
-82 <-> 64
+82 <-> 64