do not weave unreachable code -- since we cannot analyze it, we also …

…cannot weave it.

src/kilim/analysis/MethodWeaver.java

@@ -184,7 +184,7 @@ private void visitInstructions(MethodVisitor mv) {
         for (BasicBlock bb : mf.getBasicBlocks()) {
             int from = bb.startPos;
 
-            if (bb.isPausable()) {
+            if (bb.isPausable() && bb.startFrame != null) {
                 genPausableMethod(mv, bb);
                 from = bb.startPos + 1; // first instruction is consumed
             } else if (bb.isCatchHandler()) {
@@ -286,7 +286,7 @@ void genGetCurrentTask(MethodVisitor mv, BasicBlock bb) {
     private void createCallWeavers() {
         MethodFlow mf = methodFlow;
         for (BasicBlock bb : mf.getBasicBlocks()) {
-            if (!bb.isPausable()) continue;
+            if (!bb.isPausable() || bb.startFrame==null) continue;
             // No prelude needed for Task.getCurrentTask(). 
             if (bb.isGetCurrentTask()) continue; 
             CallWeaver cw = new CallWeaver(this, bb);