/**
   * Remove the local variable type table attribute (LVTT) from mg. Evidently some changes require
   * this to be updated, but without BCEL support that would be hard to do. It should be safe to
   * just delete it since it is optional and really only of use to a debugger.
   */
  public static void remove_local_variable_type_tables(MethodGen mg) {

    for (Attribute a : mg.getCodeAttributes()) {
      if (is_local_variable_type_table(a, mg.getConstantPool())) {
        mg.removeCodeAttribute(a);
      }
    }
  }
예제 #2
0
  /**
   * Processes each method in cg replacing any specified calls with static user calls.
   *
   * @param fullClassName must be packageName.className
   */
  private boolean map_calls(ClassGen cg, String fullClassName, ClassLoader loader) {

    boolean transformed = false;

    try {
      pgen = cg.getConstantPool();

      // Loop through each method in the class
      Method[] methods = cg.getMethods();
      for (int i = 0; i < methods.length; i++) {
        MethodGen mg = new MethodGen(methods[i], cg.getClassName(), pgen);

        // Get the instruction list and skip methods with no instructions
        InstructionList il = mg.getInstructionList();
        if (il == null) continue;

        if (debug) out.format("Original code: %s%n", mg.getMethod().getCode());

        instrument_method(methods[i], mg);

        // Remove the Local variable type table attribute (if any).
        // Evidently, some changes we make require this to be updated, but
        // without BCEL support, that would be hard to do.  Just delete it
        // for now (since it is optional, and we are unlikely to be used by
        // a debugger)
        for (Attribute a : mg.getCodeAttributes()) {
          if (is_local_variable_type_table(a)) {
            mg.removeCodeAttribute(a);
          }
        }

        // Update the instruction list
        mg.setInstructionList(il);
        mg.update();

        // Update the max stack and Max Locals
        mg.setMaxLocals();
        mg.setMaxStack();
        mg.update();

        // Update the method in the class
        cg.replaceMethod(methods[i], mg.getMethod());
        if (debug) out.format("Modified code: %s%n", mg.getMethod().getCode());

        // verify the new method
        // StackVer stackver = new StackVer();
        // VerificationResult vr = stackver.do_stack_ver (mg);
        // log ("vr for method %s = %s%n", mg.getName(), vr);
        // if (vr.getStatus() != VerificationResult.VERIFIED_OK) {
        //  System.out.printf ("Warning BCEL Verify failed for method %s: %s",
        //                     mg.getName(), vr);
        //  System.out.printf ("Code: %n%s%n", mg.getMethod().getCode());
        // System.exit(1);
        // }
      }

      cg.update();
    } catch (Exception e) {
      out.format("Unexpected exception encountered: " + e);
      e.printStackTrace();
    }

    return transformed;
  }