fixed JIRA JASSIST-241

src/main/javassist/CtBehavior.java

@@ -917,7 +917,9 @@ public abstract class CtBehavior extends CtMember {
         // the gap length might be a multiple of 4.
         iterator.writeByte(Opcode.NOP, pos);
         boolean wide = subr + 2 - pos > Short.MAX_VALUE;
-        pos = iterator.insertGapAt(pos, wide ? 4 : 2, false).position;
+        int len = wide ? 4 : 2;
+        CodeIterator.Gap gap = iterator.insertGapAt(pos, len, false);
+        pos = gap.position + gap.length - len;
         int offset = iterator.getMark() - pos;
         if (wide) {
             iterator.writeByte(Opcode.GOTO_W, pos);
@@ -928,7 +930,11 @@ public abstract class CtBehavior extends CtMember {
             iterator.write16bit(offset, pos + 1);
         }
         else {
-            pos = iterator.insertGapAt(pos, 2, false).position;
+            if (gap.length < 4) {
+                CodeIterator.Gap gap2 =  iterator.insertGapAt(gap.position, 2, false);
+                pos = gap2.position + gap2.length + gap.length - 4; 
+            }
+
             iterator.writeByte(Opcode.GOTO_W, pos);
             iterator.write32bit(iterator.getMark() - pos, pos + 1);
         }

src/main/javassist/bytecode/stackmap/BasicBlock.java

@@ -360,6 +360,7 @@ public class BasicBlock {
                             prev.length = m.position - prev.position;
                             // the incoming flow from dead code is not counted
                             // bb.incoming++;
+                            prev.stop = true;   // because the incoming flow is not counted.
                             prev.exit = makeArray(bb);
                         }
                     }

src/test/javassist/JvstTest4.java

@@ -661,9 +661,9 @@ public class JvstTest4 extends JvstTestRoot {
         long t2 = endTime2 - endTime;
         long t3 = endTime3 - endTime2;
         System.out.println("JIRA150: " + t1 + ", " + t2 + ", " + t3);
-        assertTrue("performance test (the next try may succeed): " + t1 + "/ 6 < " + t2,
+        assertTrue("performance test (the next try may succeed): " + t2 + " < 6 * " + t1,
                    t2 < t1 * 6);
-        assertTrue("", t3 < t1 * 3);
+        assertTrue(t3 + " < 3 * " + t1, t3 < t1 * 3);
     }
 
     public void testJIRA150b() throws Exception {

src/test/javassist/JvstTest5.java

@@ -44,4 +44,13 @@ public class JvstTest5 extends JvstTestRoot {
         Annotation[] annos = t.getAnnotations();
         assertEquals("@test5.TypeAnnoA()", annos[0].toString());
     }
+
+    public void testJIRA241() throws Exception {
+        CtClass cc = sloader.get("test5.JIRA241");
+        CtMethod testMethod = cc.getDeclaredMethod("test");
+        testMethod.insertAfter("System.out.println(\"inserted!\");");
+        cc.writeFile();
+        Object obj = make(cc.getName());
+        assertEquals(10, invoke(obj, "run"));
+    }
 }

src/test/test5/JIRA241.java

@@ -0,0 +1,33 @@
+package test5;
+
+import java.util.Random;
+import javassist.*;
+
+public class JIRA241 {
+    public int run() {
+        test(this);
+        return 10;
+    }
+
+    public static void test(Object o) {
+        //part 1
+        if (o == null) {
+            return;
+        }
+ 
+        //part 2
+        int oper = new Random().nextInt();
+        switch (oper) {
+        case 1:
+            break;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        ClassPool pool  = ClassPool.getDefault();
+        CtClass cc = pool.get("test5.JIRA241");
+        CtMethod testMethod = cc.getMethod("test", "(Ljava/lang/Object;)V");
+        testMethod.insertAfter("System.out.println(\"inserted!\");");
+        cc.writeFile();
+    }
+}