code: @Override
      public void visitCode(Code obj) {
          stack.resetForMethodEntry(this);
          nextAllocNumber = 1;
          storeToUserValue.clear();
          allocLocation.clear();
          allocToAddPCs.clear();
          optionalRanges.clear();
  
          addExceptionRanges(obj);
  
          super.visitCode(obj);
  
          for (List<Integer> pcs : allocToAddPCs.values()) {
              if (pcs.size() > 16) {
                  bugReporter.reportBug(new BugInstance(this, BugType.PSC_PRESIZE_COLLECTIONS.name(), NORMAL_PRIORITY).addClass(this).addMethod(this)
                          .addSourceLine(this, pcs.get(0).intValue()));
              }
          }
      }
docs: implements the visitor to reset the opcode stack
  
  @param obj
  the context object of the currently parsed code block