Sample implementation of rust's `unwind` crate using `unwinding` as a backend

Cargo.toml

[package]
name = "unwind"
version = "0.0.0"
license = "MIT OR Apache-2.0"
repository = "https://github.com/rust-lang/rust.git"
edition = "2021"
include = [
  '/libunwind/*',
]

[lib]
test = false
bench = false
doc = false

[dependencies]
core = { path = "../core" }
libc = { version = "0.2.79", features = ['rustc-dep-of-std'], default-features = false }
compiler_builtins = "0.1.0"
cfg-if = "1.0"

[target.'cfg(target_os = "xous")'.dependencies]
unwinding = { path = "../../unwinding", features = ['rustc-dep-of-std', 'unwinder', 'fde-custom'], default-features = false }

[build-dependencies]
cc = "1.0.76"

[features]

# Only applies for Linux and Fuchsia targets
# Static link to the in-tree build of llvm libunwind
llvm-libunwind = []

# Only applies for Linux and Fuchsia targets
# If crt-static is enabled, static link to `libunwind.a` provided by system
# If crt-static is disabled, dynamic link to `libunwind.so` provided by system
system-llvm-libunwind = []

unwinding.rs

#![allow(nonstandard_style)]

use libc::{c_int, c_void, uintptr_t};

#[repr(C)]
#[derive(Copy, Clone, PartialEq)]
pub enum _Unwind_Action {
    _UA_SEARCH_PHASE = 1,
    _UA_CLEANUP_PHASE = 2,
    _UA_HANDLER_FRAME = 4,
    _UA_FORCE_UNWIND = 8,
    _UA_END_OF_STACK = 16,
}
pub use _Unwind_Action::*;

#[repr(C)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum _Unwind_Reason_Code {
    _URC_NO_REASON = 0,
    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
    _URC_FATAL_PHASE2_ERROR = 2,
    _URC_FATAL_PHASE1_ERROR = 3,
    _URC_NORMAL_STOP = 4,
    _URC_END_OF_STACK = 5,
    _URC_HANDLER_FOUND = 6,
    _URC_INSTALL_CONTEXT = 7,
    _URC_CONTINUE_UNWIND = 8,
    _URC_FAILURE = 9, // used only by ARM EHABI
}
pub use _Unwind_Reason_Code::*;

pub use unwinding::abi::UnwindContext;
pub use unwinding::abi::UnwindException;
pub enum _Unwind_Context {}

pub type _Unwind_Exception_Class = u64;
pub type _Unwind_Word = uintptr_t;
pub type _Unwind_Ptr = uintptr_t;

pub const unwinder_private_data_size: usize = core::mem::size_of::<UnwindException>() - core::mem::size_of::<_Unwind_Exception_Class>() - core::mem::size_of::<_Unwind_Exception_Cleanup_Fn>();

pub type _Unwind_Exception_Cleanup_Fn =
    extern "C" fn(unwind_code: _Unwind_Reason_Code, exception: *mut _Unwind_Exception);

#[repr(C)]
pub struct _Unwind_Exception {
    pub exception_class: _Unwind_Exception_Class,
    pub exception_cleanup: _Unwind_Exception_Cleanup_Fn,
    pub private: [_Unwind_Word; unwinder_private_data_size],
}

pub fn _Unwind_GetDataRelBase(ctx: *mut _Unwind_Context) -> _Unwind_Ptr {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_GetDataRelBase(ctx) as _Unwind_Ptr
}

pub fn _Unwind_GetTextRelBase(ctx: *mut _Unwind_Context) -> _Unwind_Ptr {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_GetTextRelBase(ctx) as _Unwind_Ptr
}

pub fn _Unwind_GetRegionStart(ctx: *mut _Unwind_Context) -> _Unwind_Ptr {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_GetRegionStart(ctx) as _Unwind_Ptr
}

pub fn _Unwind_SetGR(ctx: *mut _Unwind_Context, reg_index: c_int, value: _Unwind_Word) {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_SetGR(ctx, reg_index, value)
}

pub fn _Unwind_SetIP(ctx: *mut _Unwind_Context, value: _Unwind_Word) {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_SetIP(ctx, value)
}

pub fn _Unwind_GetIPInfo(ctx: *mut _Unwind_Context, ip_before_insn: *mut c_int) -> _Unwind_Word {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    let ip_before_insn = unsafe { &mut *(ip_before_insn as *mut c_int) };
    unwinding::abi::_Unwind_GetIPInfo(ctx, ip_before_insn)
}

pub fn _Unwind_GetLanguageSpecificData(ctx: *mut _Unwind_Context) -> *mut c_void {
    let ctx = unsafe { &mut *(ctx as *mut UnwindContext<'_>) };
    unwinding::abi::_Unwind_GetLanguageSpecificData(ctx)
}

pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code {
    let exception = unsafe { &mut *(exception as *mut UnwindException) };
    unsafe { core::mem::transmute(unwinding::abi::_Unwind_RaiseException(exception)) }
}

pub fn _Unwind_DeleteException(exception: *mut _Unwind_Exception) {
    let exception = unsafe { &mut *(exception as *mut UnwindException)};
    unsafe { unwinding::abi::_Unwind_DeleteException(exception) }
}

pub use unwinding::custom_eh_frame_finder::{
    set_custom_eh_frame_finder, EhFrameFinder, FrameInfo, FrameInfoKind,
};