  Angle-resolved upper critical field $H_{c2}$ provides an efficient tool to
probe the gap symmetry of unconventional superconductors. We revisit the
behavior of in-plane $H_{c2}$ in $d$-wave superconductors by considering both
the orbital effect and Pauli paramagnetic effect. After carrying out systematic
analysis, we show that the maxima of $H_{c2}$ could be along either nodal or
antinodal directions of a $d$-wave superconducting gap, depending on the
specific values of a number of tuning parameters. This behavior is in contrast
to the common belief that the maxima of in-plane $H_{c2}$ are along the
direction where the superconducting gap takes its maximal value. Therefore,
identifying the precise $d$-wave gap symmetry through fitting experiments
results of angle-resolved $H_{c2}$ with model calculations at a fixed
temperature, as widely used in previous studies, is difficult and practically
unreliable. However, our extensive analysis of angle-resolved $H_{c2}$ show
that there is a critical temperature $T^{*}$: in-plane $H_{c2}$ exhibits its
maxima along nodal directions at $T < T^{*}$ and along antinodal directions at
$T^{*} < T < T_c$. The concrete value of $T^{*}$ may change as other parameters
vary, but the existence of $\pi/4$ shift of $H_{c2}$ at $T^{\ast}$ appears to
be a general feature. Thus a better method to identify the precise $d$-wave gap
symmetry is to measure $H_{c2}$ at a number of different temperatures, and
examine whether there is a $\pi/4$ shift in its angular dependence at certain
$T^{*}$. We further show that Landau level mixing does not change this general
feature. However, in the presence of Fulde-Ferrell-Larkin-Ovchinnikov state,
the angular dependence of $H_{c2}$ becomes quite complicated, which makes it
more difficult to determine the gap symmetry by measuring $H_{c2}$.
