private void findSubroutine()

in asm-analysis/src/main/java/org/objectweb/asm/tree/analysis/Analyzer.java [405:474]
63 lines of code
23 McCabe index (conditional complexity)

  private void findSubroutine(
      final int insnIndex, final Subroutine subroutine, final List<AbstractInsnNode> jsrInsns)
      throws AnalyzerException {
    ArrayList<Integer> instructionIndicesToProcess = new ArrayList<>();
    instructionIndicesToProcess.add(insnIndex);
    while (!instructionIndicesToProcess.isEmpty()) {
      int currentInsnIndex =
          instructionIndicesToProcess.remove(instructionIndicesToProcess.size() - 1);
      if (currentInsnIndex < 0 || currentInsnIndex >= insnListSize) {
        throw new AnalyzerException(null, "Execution can fall off the end of the code");
      }
      if (subroutines[currentInsnIndex] != null) {
        continue;
      }
      subroutines[currentInsnIndex] = new Subroutine(subroutine);
      AbstractInsnNode currentInsn = insnList.get(currentInsnIndex);

      // Push the normal successors of currentInsn onto instructionIndicesToProcess.
      if (currentInsn instanceof JumpInsnNode) {
        if (currentInsn.getOpcode() == JSR) {
          // Do not follow a jsr, it leads to another subroutine!
          jsrInsns.add(currentInsn);
        } else {
          JumpInsnNode jumpInsn = (JumpInsnNode) currentInsn;
          instructionIndicesToProcess.add(insnList.indexOf(jumpInsn.label));
        }
      } else if (currentInsn instanceof TableSwitchInsnNode) {
        TableSwitchInsnNode tableSwitchInsn = (TableSwitchInsnNode) currentInsn;
        findSubroutine(insnList.indexOf(tableSwitchInsn.dflt), subroutine, jsrInsns);
        for (int i = tableSwitchInsn.labels.size() - 1; i >= 0; --i) {
          LabelNode labelNode = tableSwitchInsn.labels.get(i);
          instructionIndicesToProcess.add(insnList.indexOf(labelNode));
        }
      } else if (currentInsn instanceof LookupSwitchInsnNode) {
        LookupSwitchInsnNode lookupSwitchInsn = (LookupSwitchInsnNode) currentInsn;
        findSubroutine(insnList.indexOf(lookupSwitchInsn.dflt), subroutine, jsrInsns);
        for (int i = lookupSwitchInsn.labels.size() - 1; i >= 0; --i) {
          LabelNode labelNode = lookupSwitchInsn.labels.get(i);
          instructionIndicesToProcess.add(insnList.indexOf(labelNode));
        }
      }

      // Push the exception handler successors of currentInsn onto instructionIndicesToProcess.
      List<TryCatchBlockNode> insnHandlers = handlers[currentInsnIndex];
      if (insnHandlers != null) {
        for (TryCatchBlockNode tryCatchBlock : insnHandlers) {
          instructionIndicesToProcess.add(insnList.indexOf(tryCatchBlock.handler));
        }
      }

      // Push the next instruction, if the control flow can go from currentInsn to the next.
      switch (currentInsn.getOpcode()) {
        case GOTO:
        case RET:
        case TABLESWITCH:
        case LOOKUPSWITCH:
        case IRETURN:
        case LRETURN:
        case FRETURN:
        case DRETURN:
        case ARETURN:
        case RETURN:
        case ATHROW:
          break;
        default:
          instructionIndicesToProcess.add(currentInsnIndex + 1);
          break;
      }
    }
  }