Auto merge of - RalfJung:abort, r=Mark-Simulacrum

make abort intrinsic safe, and correct its documentation

Turns out `std::process::abort` is not the same as the intrinsic, the comment was just wrong. Quoting from the unix implementation:
```
// On Unix-like platforms, libc::abort will unregister signal handlers
// including the SIGABRT handler, preventing the abort from being blocked, and
// fclose streams, with the side effect of flushing them so libc buffered
// output will be printed.  Additionally the shell will generally print a more
// understandable error message like "Abort trap" rather than "Illegal
// instruction" that intrinsics::abort would cause, as intrinsics::abort is
// implemented as an illegal instruction.
```
This commit is contained in:
bors 2020-05-17 12:49:01 +00:00
commit 34cce58d81
10 changed files with 55 additions and 14 deletions
src
liballoc
libcore
libpanic_unwind
librustc_typeck/check
libstd

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@ -2027,6 +2027,8 @@ trait RcBoxPtr<T: ?Sized> {
// nevertheless, we insert an abort here to hint LLVM at
// an otherwise missed optimization.
if strong == 0 || strong == usize::max_value() {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}
@ -2053,6 +2055,8 @@ trait RcBoxPtr<T: ?Sized> {
// nevertheless, we insert an abort here to hint LLVM at
// an otherwise missed optimization.
if weak == 0 || weak == usize::max_value() {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}

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@ -1096,6 +1096,8 @@ impl<T: ?Sized> Clone for Arc<T> {
// We abort because such a program is incredibly degenerate, and we
// don't care to support it.
if old_size > MAX_REFCOUNT {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}
@ -1614,6 +1616,8 @@ impl<T: ?Sized> Weak<T> {
// See comments in `Arc::clone` for why we do this (for `mem::forget`).
if n > MAX_REFCOUNT {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}
@ -1753,6 +1757,7 @@ impl<T: ?Sized> Clone for Weak<T> {
// See comments in Arc::clone() for why we do this (for mem::forget).
if old_size > MAX_REFCOUNT {
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
abort();
}

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@ -133,10 +133,9 @@
//! `Cell<T>`.
//!
//! ```
//! #![feature(core_intrinsics)]
//! use std::cell::Cell;
//! use std::ptr::NonNull;
//! use std::intrinsics::abort;
//! use std::process::abort;
//! use std::marker::PhantomData;
//!
//! struct Rc<T: ?Sized> {
@ -173,7 +172,7 @@
//! .strong
//! .set(self.strong()
//! .checked_add(1)
//! .unwrap_or_else(|| unsafe { abort() }));
//! .unwrap_or_else(|| abort() ));
//! }
//! }
//!

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@ -918,7 +918,7 @@ extern "rust-intrinsic" {
/// Aborts the execution of the process.
///
/// The stabilized version of this intrinsic is
/// A more user-friendly and stable version of this operation is
/// [`std::process::abort`](../../std/process/fn.abort.html).
pub fn abort() -> !;

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@ -39,8 +39,12 @@ use crate::panic::{Location, PanicInfo};
#[lang = "panic"] // needed by codegen for panic on overflow and other `Assert` MIR terminators
pub fn panic(expr: &str) -> ! {
if cfg!(feature = "panic_immediate_abort") {
// remove `unsafe` (and safety comment) on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
// SAFETY: the `abort` intrinsic has no requirements to be called.
unsafe { super::intrinsics::abort() }
unsafe {
super::intrinsics::abort()
}
}
// Use Arguments::new_v1 instead of format_args!("{}", expr) to potentially
@ -58,8 +62,12 @@ pub fn panic(expr: &str) -> ! {
#[lang = "panic_bounds_check"] // needed by codegen for panic on OOB array/slice access
fn panic_bounds_check(index: usize, len: usize) -> ! {
if cfg!(feature = "panic_immediate_abort") {
// remove `unsafe` (and safety comment) on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
// SAFETY: the `abort` intrinsic has no requirements to be called.
unsafe { super::intrinsics::abort() }
unsafe {
super::intrinsics::abort()
}
}
panic!("index out of bounds: the len is {} but the index is {}", len, index)
@ -72,8 +80,12 @@ fn panic_bounds_check(index: usize, len: usize) -> ! {
#[track_caller]
pub fn panic_fmt(fmt: fmt::Arguments<'_>) -> ! {
if cfg!(feature = "panic_immediate_abort") {
// remove `unsafe` (and safety comment) on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
// SAFETY: the `abort` intrinsic has no requirements to be called.
unsafe { super::intrinsics::abort() }
unsafe {
super::intrinsics::abort()
}
}
// NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call

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@ -327,5 +327,8 @@ pub unsafe fn cleanup(payload: *mut u8) -> Box<dyn Any + Send> {
#[lang = "eh_personality"]
#[cfg(not(test))]
fn rust_eh_personality() {
unsafe { core::intrinsics::abort() }
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
core::intrinsics::abort()
}
}

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@ -69,7 +69,7 @@ fn equate_intrinsic_type<'tcx>(
/// Returns `true` if the given intrinsic is unsafe to call or not.
pub fn intrinsic_operation_unsafety(intrinsic: &str) -> hir::Unsafety {
match intrinsic {
"size_of" | "min_align_of" | "needs_drop" | "caller_location" | "size_of_val"
"abort" | "size_of" | "min_align_of" | "needs_drop" | "caller_location" | "size_of_val"
| "min_align_of_val" | "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow"
| "wrapping_add" | "wrapping_sub" | "wrapping_mul" | "saturating_add"
| "saturating_sub" | "rotate_left" | "rotate_right" | "ctpop" | "ctlz" | "cttz"
@ -130,7 +130,9 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
}
};
(n_tps, inputs, output, hir::Unsafety::Unsafe)
} else if &name[..] == "abort" || &name[..] == "unreachable" {
} else if &name[..] == "abort" {
(0, Vec::new(), tcx.types.never, hir::Unsafety::Normal)
} else if &name[..] == "unreachable" {
(0, Vec::new(), tcx.types.never, hir::Unsafety::Unsafe)
} else {
let unsafety = intrinsic_operation_unsafety(&name[..]);

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@ -332,7 +332,10 @@ pub fn panicking() -> bool {
#[cfg_attr(feature = "panic_immediate_abort", inline)]
pub fn begin_panic_fmt(msg: &fmt::Arguments<'_>) -> ! {
if cfg!(feature = "panic_immediate_abort") {
unsafe { intrinsics::abort() }
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
intrinsics::abort()
}
}
let info = PanicInfo::internal_constructor(Some(msg), Location::caller());
@ -398,7 +401,10 @@ pub fn begin_panic_handler(info: &PanicInfo<'_>) -> ! {
#[track_caller]
pub fn begin_panic<M: Any + Send>(msg: M) -> ! {
if cfg!(feature = "panic_immediate_abort") {
unsafe { intrinsics::abort() }
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
intrinsics::abort()
}
}
rust_panic_with_hook(&mut PanicPayload::new(msg), None, Location::caller());
@ -458,7 +464,10 @@ fn rust_panic_with_hook(
"thread panicked while processing \
panic. aborting.\n"
));
unsafe { intrinsics::abort() }
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
intrinsics::abort()
}
}
unsafe {
@ -493,7 +502,10 @@ fn rust_panic_with_hook(
"thread panicked while panicking. \
aborting.\n"
));
unsafe { intrinsics::abort() }
#[cfg_attr(not(bootstrap), allow(unused_unsafe))] // remove `unsafe` on bootstrap bump
unsafe {
intrinsics::abort()
}
}
rust_panic(payload)

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@ -354,6 +354,8 @@ impl<T> Packet<T> {
// See comments on Arc::clone() on why we do this (for `mem::forget`).
if old_count > MAX_REFCOUNT {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}

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@ -358,6 +358,8 @@ impl<T> Packet<T> {
// See comments on Arc::clone() on why we do this (for `mem::forget`).
if old_count > MAX_REFCOUNT {
// remove `unsafe` on bootstrap bump
#[cfg_attr(not(bootstrap), allow(unused_unsafe))]
unsafe {
abort();
}