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use alloc::boxed::Box;
use alloc::vec::Vec;
use core::ffi::c_void;
extern "Rust" {
fn miri_backtrace_size(flags: u64) -> usize;
fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
fn miri_resolve_frame(ptr: *mut (), flags: u64) -> MiriFrame;
fn miri_resolve_frame_names(ptr: *mut (), flags: u64, name_buf: *mut u8, filename_buf: *mut u8);
}
#[repr(C)]
pub struct MiriFrame {
pub name_len: usize,
pub filename_len: usize,
pub lineno: u32,
pub colno: u32,
pub fn_ptr: *mut c_void,
}
#[derive(Clone, Debug)]
pub struct FullMiriFrame {
pub name: Box<[u8]>,
pub filename: Box<[u8]>,
pub lineno: u32,
pub colno: u32,
pub fn_ptr: *mut c_void,
}
#[derive(Debug, Clone)]
pub struct Frame {
pub addr: *mut c_void,
pub inner: FullMiriFrame,
}
// SAFETY: Miri guarantees that the returned pointer
// can be used from any thread.
unsafe impl Send for Frame {}
unsafe impl Sync for Frame {}
impl Frame {
pub fn ip(&self) -> *mut c_void {
self.addr
}
pub fn sp(&self) -> *mut c_void {
core::ptr::null_mut()
}
pub fn symbol_address(&self) -> *mut c_void {
self.inner.fn_ptr
}
pub fn module_base_address(&self) -> Option<*mut c_void> {
None
}
}
pub fn trace<F: FnMut(&super::Frame) -> bool>(cb: F) {
// SAFETY: Miri guarantees that the backtrace API functions
// can be called from any thread.
unsafe { trace_unsynchronized(cb) };
}
pub fn resolve_addr(ptr: *mut c_void) -> Frame {
// SAFETY: Miri will stop execution with an error if this pointer
// is invalid.
let frame = unsafe { miri_resolve_frame(ptr as *mut (), 1) };
let mut name = Vec::with_capacity(frame.name_len);
let mut filename = Vec::with_capacity(frame.filename_len);
// SAFETY: name and filename have been allocated with the amount
// of memory miri has asked for, and miri guarantees it will initialize it
unsafe {
miri_resolve_frame_names(ptr as *mut (), 0, name.as_mut_ptr(), filename.as_mut_ptr());
name.set_len(frame.name_len);
filename.set_len(frame.filename_len);
}
Frame {
addr: ptr,
inner: FullMiriFrame {
name: name.into(),
filename: filename.into(),
lineno: frame.lineno,
colno: frame.colno,
fn_ptr: frame.fn_ptr,
},
}
}
unsafe fn trace_unsynchronized<F: FnMut(&super::Frame) -> bool>(mut cb: F) {
let len = miri_backtrace_size(0);
let mut frames = Vec::with_capacity(len);
miri_get_backtrace(1, frames.as_mut_ptr());
frames.set_len(len);
for ptr in frames.iter() {
let frame = resolve_addr(*ptr as *mut c_void);
if !cb(&super::Frame { inner: frame }) {
return;
}
}
}
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