Method find

crates/unwinder/src/throw.rs:45–78

Implementation of stack-walking to find a handler. This function searches for a handler in the given range of stack frames, starting from the throw stub and up to a specified entry frame. # Safety The safety of this function is the same as [`crate::visit_frames`] where the values passed in configuring the frame pointer walk must be correct and Wasm-defined for this to not have UB.

(
        unwind: &dyn Unwind,
        frame_handler: F,
        exit_pc: usize,
        exit_trampoline_frame: usize,
        entry_frame: usize,
    )

    /// values passed in configuring the frame pointer walk must be correct and
    /// Wasm-defined for this to not have UB.
    pub unsafe fn find<F: Fn(&Frame) -> Option<(usize, usize)>>(
        unwind: &dyn Unwind,
        frame_handler: F,
        exit_pc: usize,
        exit_trampoline_frame: usize,
        entry_frame: usize,
    ) -> Option<Handler> {
        // SAFETY: the safety of `visit_frames` relies on the correctness of the
        // parameters passed in which is forwarded as a contract to this function
        // tiself.
        let result = unsafe {
            crate::stackwalk::visit_frames(
                unwind,
                exit_pc,
                exit_trampoline_frame,
                entry_frame,
                |frame| {
                    log::trace!("visit_frame: frame {frame:?}");
                    if let Some((handler_pc, handler_sp)) = frame_handler(&frame) {
                        return ControlFlow::Break(Handler {
                            pc: handler_pc,
                            sp: handler_sp,
                            fp: frame.fp(),
                        });
                    }
                    ControlFlow::Continue(())
                },
            )
        };
        match result {
            ControlFlow::Break(handler) => Some(handler),
            ControlFlow::Continue(()) => None,
        }
    }
}