debug build of share objects(.so) using fcitx won't work

[zhirshya]

Hello,
I have a custom IME based on fcitx4 with 2 shared objects (so) constitute the main part. The problem is the custom IME crashes and I want to debug it. I built debug versions of those 2 .SO and put in corresponding system directories, being /usr/lib/aarch64-linux-gnu/fcitx/ and /opt/apps/com.company.customime/files/bin/. Then the custom IME won't work, can't input with it, and it won't show word selection window and language bar icons. However, the original release build can input characters with word selection window and language bar icons shown, but crashes after a few lines of text are input.
**The only change made in fcitx source code is the language id array length, modified to accommodate a language ID with 10 character, I think this shouldn't be the problem.

So my questions are:
Is it because of debug build?
How to debug the 2 shared objects correctly?