3ef75d5774
Unwinding across an FFI boundary is undefined behaviour, so we can mark all external function as nounwind. The obvious exception are those functions that actually perform the unwinding.
71 lines
2.9 KiB
Rust
71 lines
2.9 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
//! Panic support for libcore
|
|
//!
|
|
//! The core library cannot define panicking, but it does *declare* panicking. This
|
|
//! means that the functions inside of libcore are allowed to panic, but to be
|
|
//! useful an upstream crate must define panicking for libcore to use. The current
|
|
//! interface for panicking is:
|
|
//!
|
|
//! ```ignore
|
|
//! fn panic_impl(fmt: fmt::Arguments, &(&'static str, u32)) -> !;
|
|
//! ```
|
|
//!
|
|
//! This definition allows for panicking with any general message, but it does not
|
|
//! allow for failing with a `Box<Any>` value. The reason for this is that libcore
|
|
//! is not allowed to allocate.
|
|
//!
|
|
//! This module contains a few other panicking functions, but these are just the
|
|
//! necessary lang items for the compiler. All panics are funneled through this
|
|
//! one function. Currently, the actual symbol is declared in the standard
|
|
//! library, but the location of this may change over time.
|
|
|
|
#![allow(dead_code, missing_docs)]
|
|
#![unstable(feature = "core_panic",
|
|
reason = "internal details of the implementation of the `panic!` \
|
|
and related macros",
|
|
issue = "0")]
|
|
|
|
use fmt;
|
|
|
|
#[cold] #[inline(never)] // this is the slow path, always
|
|
#[lang = "panic"]
|
|
pub fn panic(expr_file_line: &(&'static str, &'static str, u32)) -> ! {
|
|
// Use Arguments::new_v1 instead of format_args!("{}", expr) to potentially
|
|
// reduce size overhead. The format_args! macro uses str's Display trait to
|
|
// write expr, which calls Formatter::pad, which must accommodate string
|
|
// truncation and padding (even though none is used here). Using
|
|
// Arguments::new_v1 may allow the compiler to omit Formatter::pad from the
|
|
// output binary, saving up to a few kilobytes.
|
|
let (expr, file, line) = *expr_file_line;
|
|
panic_fmt(fmt::Arguments::new_v1(&[expr], &[]), &(file, line))
|
|
}
|
|
|
|
#[cold] #[inline(never)]
|
|
#[lang = "panic_bounds_check"]
|
|
fn panic_bounds_check(file_line: &(&'static str, u32),
|
|
index: usize, len: usize) -> ! {
|
|
panic_fmt(format_args!("index out of bounds: the len is {} but the index is {}",
|
|
len, index), file_line)
|
|
}
|
|
|
|
#[cold] #[inline(never)]
|
|
pub fn panic_fmt(fmt: fmt::Arguments, file_line: &(&'static str, u32)) -> ! {
|
|
#[allow(improper_ctypes)]
|
|
extern {
|
|
#[lang = "panic_fmt"]
|
|
#[unwind]
|
|
fn panic_impl(fmt: fmt::Arguments, file: &'static str, line: u32) -> !;
|
|
}
|
|
let (file, line) = *file_line;
|
|
unsafe { panic_impl(fmt, file, line) }
|
|
}
|