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-rw-r--r--library/panic_unwind/src/emcc.rs40
1 files changed, 28 insertions, 12 deletions
diff --git a/library/panic_unwind/src/emcc.rs b/library/panic_unwind/src/emcc.rs
index 7c233c7c3..c6d423085 100644
--- a/library/panic_unwind/src/emcc.rs
+++ b/library/panic_unwind/src/emcc.rs
@@ -47,7 +47,12 @@ static EXCEPTION_TYPE_INFO: TypeInfo = TypeInfo {
name: b"rust_panic\0".as_ptr(),
};
+// NOTE(nbdd0121): The `canary` field will be part of stable ABI after `c_unwind` stabilization.
+#[repr(C)]
struct Exception {
+ // See `gcc.rs` on why this is present. We already have a static here so just use it.
+ canary: *const TypeInfo,
+
// This is necessary because C++ code can capture our exception with
// std::exception_ptr and rethrow it multiple times, possibly even in
// another thread.
@@ -70,27 +75,38 @@ pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
let catch_data = &*(ptr as *mut CatchData);
let adjusted_ptr = __cxa_begin_catch(catch_data.ptr as *mut libc::c_void) as *mut Exception;
- let out = if catch_data.is_rust_panic {
- let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::SeqCst);
- if was_caught {
- // Since cleanup() isn't allowed to panic, we just abort instead.
- intrinsics::abort();
- }
- (*adjusted_ptr).data.take().unwrap()
- } else {
+ if !catch_data.is_rust_panic {
super::__rust_foreign_exception();
- };
+ }
+
+ let canary = ptr::addr_of!((*adjusted_ptr).canary).read();
+ if !ptr::eq(canary, &EXCEPTION_TYPE_INFO) {
+ super::__rust_foreign_exception();
+ }
+
+ let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::SeqCst);
+ if was_caught {
+ // Since cleanup() isn't allowed to panic, we just abort instead.
+ intrinsics::abort();
+ }
+ let out = (*adjusted_ptr).data.take().unwrap();
__cxa_end_catch();
out
}
pub unsafe fn panic(data: Box<dyn Any + Send>) -> u32 {
- let sz = mem::size_of_val(&data);
- let exception = __cxa_allocate_exception(sz) as *mut Exception;
+ let exception = __cxa_allocate_exception(mem::size_of::<Exception>()) as *mut Exception;
if exception.is_null() {
return uw::_URC_FATAL_PHASE1_ERROR as u32;
}
- ptr::write(exception, Exception { caught: AtomicBool::new(false), data: Some(data) });
+ ptr::write(
+ exception,
+ Exception {
+ canary: &EXCEPTION_TYPE_INFO,
+ caught: AtomicBool::new(false),
+ data: Some(data),
+ },
+ );
__cxa_throw(exception as *mut _, &EXCEPTION_TYPE_INFO, exception_cleanup);
}