Semimartingale representation of $f(x) = e^{i\alpha x}$

Question

Let $(B_t)_{t≥0}$ be a Brownian motion, let $\alpha$ be a real number, and let $f : \mathbb{R} → \mathbb{C}$ be the function $f(x) = e^{i\alpha x}$. Which semimartingale representation does the process $X$, such that $X_t = f(B_t), t ≥ 0$ satisfy ? Thanks in advance for any help!