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rustc: Switch extern
functions to abort by default on panic
#55982
Conversation
r? @zackmdavis (rust_highfive has picked a reviewer for you, use r? to override) |
@bors r+ |
📌 Commit 6ea11fdc92286ab509bd02029246d9a6d5cbd3a7 has been approved by |
FWIW I still personally feel like changing stable behavior without providing a stabilized way to get back the old behavior is not great, but I'm not going to block this myself, both because I think this is fairly rare and the new behavior seems overall later. |
Maybe we should do a Crater run for this? |
@bors: r- Seems fine by me to hold off on a crater run happening! |
@bors: try |
⌛ Trying commit 6ea11fdc92286ab509bd02029246d9a6d5cbd3a7 with merge 2e026d6e5d7621634147ad4c8074f1d964dbb1be... |
☀️ Test successful - status-travis |
@craterbot run start=master#6b9b97bd9b704f85f0184f7a213cc4d62bd9654c end=try#2e026d6e5d7621634147ad4c8074f1d964dbb1be mode=build-and-test |
👌 Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
🚧 Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
🎉 Experiment
|
From that report there are four legitimate-looking regressions
In testing I've also noticed that the compiler no longer emits I've now pushed a follow-up commit to fix the regression, now applying |
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The job Click to expand the log.
I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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This sounds like the default is unchanged, and this PR doesn’t do anything without |
Sure! @SimonSapin does this clear things up? This was intended to land way back in 1.24, but it was backed out due to breakage which has long since been fixed. Prior to this PR a crate could panic and unwind past an extern fn foo() {
panic!();
}
fn main() {
foo();
} This PR changes the behavior of generated code to be sound-by-default. If an The implementation in this PR is pretty simple because an unstable |
Yes this is better, thanks! I don’t know if this example is actually UB though. I though what was undefined was unwinding from Rust into a call stack of another language. |
You can explore the UB through the IR of a program like this: #![crate_type = "lib"]
#[inline(never)]
extern fn foo() {
panic!("x");
}
struct A;
impl Drop for A {
fn drop(&mut self) {
extern { fn foo(); }
unsafe { foo(); }
}
}
pub fn bar() {
let _x = A;
foo();
} The compiler places the
Note that recent compilers have a bug where they don't place |
Ok I see. I didn’t know about |
Pkgsrc changes: * Bump required rust version to build to 1.32.0. * Adapt patches to changed file locations. * Since we now patch some more vendor/ modules, doctor the corresponding .cargo-checksum.json files accordingly Upstream changes: Version 1.33.0 (2019-02-28) ========================== Language -------- - [You can now use the `cfg(target_vendor)` attribute.][57465] E.g. `#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }` - [Integer patterns such as in a match expression can now be exhaustive.][56362] E.g. You can have match statement on a `u8` that covers `0..=255` and you would no longer be required to have a `_ => unreachable!()` case. - [You can now have multiple patterns in `if let` and `while let` expressions.][57532] You can do this with the same syntax as a `match` expression. E.g. ```rust enum Creature { Crab(String), Lobster(String), Person(String), } fn main() { let state = Creature::Crab("Ferris"); if let Creature::Crab(name) | Creature::Person(name) = state { println!("This creature's name is: {}", name); } } ``` - [You can now have irrefutable `if let` and `while let` patterns.][57535] Using this feature will by default produce a warning as this behaviour can be unintuitive. E.g. `if let _ = 5 {}` - [You can now use `let` bindings, assignments, expression statements, and irrefutable pattern destructuring in const functions.][57175] - [You can now call unsafe const functions.][57067] E.g. ```rust const unsafe fn foo() -> i32 { 5 } const fn bar() -> i32 { unsafe { foo() } } ``` - [You can now specify multiple attributes in a `cfg_attr` attribute.][57332] E.g. `#[cfg_attr(all(), must_use, optimize)]` - [You can now specify a specific alignment with the `#[repr(packed)]` attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a struct with an alignment of 2 bytes and a size of 6 bytes. - [You can now import an item from a module as an `_`.][56303] This allows you to import a trait's impls, and not have the name in the namespace. E.g. ```rust use std::io::Read as _; // Allowed as there is only one `Read` in the module. pub trait Read {} ``` - [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805]. Compiler -------- - [You can now set a linker flavor for `rustc` with the `-Clinker-flavor` command line argument.][56351] - [The mininum required LLVM version has been bumped to 6.0.][56642] - [Added support for the PowerPC64 architecture on FreeBSD.][57615] - [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to tier 2 support.][57130] Visit the [platform support][platform-support] page for information on Rust's platform support. - [Added support for the `thumbv7neon-linux-androideabi` and `thumbv7neon-unknown-linux-gnueabihf` targets.][56947] - [Added support for the `x86_64-unknown-uefi` target.][56769] Libraries --------- - [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const` functions for all numeric types.][57566] - [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul, shl, shr}` are now `const` functions for all numeric types.][57105] - [The methods `is_positive` and `is_negative` are now `const` functions for all signed numeric types.][57105] - [The `get` method for all `NonZero` types is now `const`.][57167] - [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`, `swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all numeric types.][57234] - [`Ipv4Addr::new` is now a `const` function][57234] Stabilized APIs --------------- - [`unix::FileExt::read_exact_at`] - [`unix::FileExt::write_all_at`] - [`Option::transpose`] - [`Result::transpose`] - [`convert::identity`] - [`pin::Pin`] - [`marker::Unpin`] - [`marker::PhantomPinned`] - [`Vec::resize_with`] - [`VecDeque::resize_with`] - [`Duration::as_millis`] - [`Duration::as_micros`] - [`Duration::as_nanos`] Cargo ----- - [Cargo should now rebuild a crate if a file was modified during the initial build.][cargo/6484] Compatibility Notes ------------------- - The methods `str::{trim_left, trim_right, trim_left_matches, trim_right_matches}` are now deprecated in the standard library, and their usage will now produce a warning. Please use the `str::{trim_start, trim_end, trim_start_matches, trim_end_matches}` methods instead. - The `Error::cause` method has been deprecated in favor of `Error::source` which supports downcasting. [55982]: rust-lang/rust#55982 [56303]: rust-lang/rust#56303 [56351]: rust-lang/rust#56351 [56362]: rust-lang/rust#56362 [56642]: rust-lang/rust#56642 [56769]: rust-lang/rust#56769 [56805]: rust-lang/rust#56805 [56947]: rust-lang/rust#56947 [57049]: rust-lang/rust#57049 [57067]: rust-lang/rust#57067 [57105]: rust-lang/rust#57105 [57130]: rust-lang/rust#57130 [57167]: rust-lang/rust#57167 [57175]: rust-lang/rust#57175 [57234]: rust-lang/rust#57234 [57332]: rust-lang/rust#57332 [57465]: rust-lang/rust#57465 [57532]: rust-lang/rust#57532 [57535]: rust-lang/rust#57535 [57566]: rust-lang/rust#57566 [57615]: rust-lang/rust#57615 [cargo/6484]: rust-lang/cargo#6484 [`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at [`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at [`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose [`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose [`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html [`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html [`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html [`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html [`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with [`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with [`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis [`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros [`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos [platform-support]: https://forge.rust-lang.org/platform-support.html
Pkgsrc changes: * Bump required rust version to build to 1.32.0. * Adapt patches to changed file locations. * Since we now patch some more vendor/ modules, doctor the corresponding .cargo-checksum.json files accordingly Upstream changes: Version 1.33.0 (2019-02-28) ========================== Language -------- - [You can now use the `cfg(target_vendor)` attribute.][57465] E.g. `#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }` - [Integer patterns such as in a match expression can now be exhaustive.][56362] E.g. You can have match statement on a `u8` that covers `0..=255` and you would no longer be required to have a `_ => unreachable!()` case. - [You can now have multiple patterns in `if let` and `while let` expressions.][57532] You can do this with the same syntax as a `match` expression. E.g. ```rust enum Creature { Crab(String), Lobster(String), Person(String), } fn main() { let state = Creature::Crab("Ferris"); if let Creature::Crab(name) | Creature::Person(name) = state { println!("This creature's name is: {}", name); } } ``` - [You can now have irrefutable `if let` and `while let` patterns.][57535] Using this feature will by default produce a warning as this behaviour can be unintuitive. E.g. `if let _ = 5 {}` - [You can now use `let` bindings, assignments, expression statements, and irrefutable pattern destructuring in const functions.][57175] - [You can now call unsafe const functions.][57067] E.g. ```rust const unsafe fn foo() -> i32 { 5 } const fn bar() -> i32 { unsafe { foo() } } ``` - [You can now specify multiple attributes in a `cfg_attr` attribute.][57332] E.g. `#[cfg_attr(all(), must_use, optimize)]` - [You can now specify a specific alignment with the `#[repr(packed)]` attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a struct with an alignment of 2 bytes and a size of 6 bytes. - [You can now import an item from a module as an `_`.][56303] This allows you to import a trait's impls, and not have the name in the namespace. E.g. ```rust use std::io::Read as _; // Allowed as there is only one `Read` in the module. pub trait Read {} ``` - [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805]. Compiler -------- - [You can now set a linker flavor for `rustc` with the `-Clinker-flavor` command line argument.][56351] - [The mininum required LLVM version has been bumped to 6.0.][56642] - [Added support for the PowerPC64 architecture on FreeBSD.][57615] - [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to tier 2 support.][57130] Visit the [platform support][platform-support] page for information on Rust's platform support. - [Added support for the `thumbv7neon-linux-androideabi` and `thumbv7neon-unknown-linux-gnueabihf` targets.][56947] - [Added support for the `x86_64-unknown-uefi` target.][56769] Libraries --------- - [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const` functions for all numeric types.][57566] - [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul, shl, shr}` are now `const` functions for all numeric types.][57105] - [The methods `is_positive` and `is_negative` are now `const` functions for all signed numeric types.][57105] - [The `get` method for all `NonZero` types is now `const`.][57167] - [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`, `swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all numeric types.][57234] - [`Ipv4Addr::new` is now a `const` function][57234] Stabilized APIs --------------- - [`unix::FileExt::read_exact_at`] - [`unix::FileExt::write_all_at`] - [`Option::transpose`] - [`Result::transpose`] - [`convert::identity`] - [`pin::Pin`] - [`marker::Unpin`] - [`marker::PhantomPinned`] - [`Vec::resize_with`] - [`VecDeque::resize_with`] - [`Duration::as_millis`] - [`Duration::as_micros`] - [`Duration::as_nanos`] Cargo ----- - [Cargo should now rebuild a crate if a file was modified during the initial build.][cargo/6484] Compatibility Notes ------------------- - The methods `str::{trim_left, trim_right, trim_left_matches, trim_right_matches}` are now deprecated in the standard library, and their usage will now produce a warning. Please use the `str::{trim_start, trim_end, trim_start_matches, trim_end_matches}` methods instead. - The `Error::cause` method has been deprecated in favor of `Error::source` which supports downcasting. [55982]: rust-lang/rust#55982 [56303]: rust-lang/rust#56303 [56351]: rust-lang/rust#56351 [56362]: rust-lang/rust#56362 [56642]: rust-lang/rust#56642 [56769]: rust-lang/rust#56769 [56805]: rust-lang/rust#56805 [56947]: rust-lang/rust#56947 [57049]: rust-lang/rust#57049 [57067]: rust-lang/rust#57067 [57105]: rust-lang/rust#57105 [57130]: rust-lang/rust#57130 [57167]: rust-lang/rust#57167 [57175]: rust-lang/rust#57175 [57234]: rust-lang/rust#57234 [57332]: rust-lang/rust#57332 [57465]: rust-lang/rust#57465 [57532]: rust-lang/rust#57532 [57535]: rust-lang/rust#57535 [57566]: rust-lang/rust#57566 [57615]: rust-lang/rust#57615 [cargo/6484]: rust-lang/cargo#6484 [`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at [`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at [`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose [`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose [`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html [`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html [`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html [`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html [`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with [`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with [`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis [`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros [`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos [platform-support]: https://forge.rust-lang.org/platform-support.html
…arking-rust-abi-unwind-issue-64655, r=alexcrichton Always mark rust and rust-call abi's as unwind PR rust-lang#63909 identified a bug that had been injected by PR rust-lang#55982. As discussed on rust-lang#64655 (comment) , we started marking extern items as nounwind, *even* extern items that said they were using "Rust" or "rust-call" ABI. This is a more targeted variant of PR rust-lang#63909 that fixes the above bug. Fix rust-lang#64655 ---- I personally suspect we will want PR rust-lang#63909 to land in the long-term But: * it is not certain that PR rust-lang#63909 *will* land, * more importantly, PR rust-lang#63909 almost certainly will not be backported to beta/stable. The identified bug was more severe than I think anyone realized (apart from perhaps @gnzlbg, as noted [here](rust-lang#63909 (comment))). Thus, I was motivated to write this PR, which fixes *just* the issue with extern rust/rust-call functions, and deliberately avoids injecting further deviation from current behavior (you can see further notes on this in the comments of the code added here).
…arking-rust-abi-unwind-issue-64655, r=alexcrichton Always mark rust and rust-call abi's as unwind PR rust-lang#63909 identified a bug that had been injected by PR rust-lang#55982. As discussed on rust-lang#64655 (comment) , we started marking extern items as nounwind, *even* extern items that said they were using "Rust" or "rust-call" ABI. This is a more targeted variant of PR rust-lang#63909 that fixes the above bug. Fix rust-lang#64655 ---- I personally suspect we will want PR rust-lang#63909 to land in the long-term But: * it is not certain that PR rust-lang#63909 *will* land, * more importantly, PR rust-lang#63909 almost certainly will not be backported to beta/stable. The identified bug was more severe than I think anyone realized (apart from perhaps @gnzlbg, as noted [here](rust-lang#63909 (comment))). Thus, I was motivated to write this PR, which fixes *just* the issue with extern rust/rust-call functions, and deliberately avoids injecting further deviation from current behavior (you can see further notes on this in the comments of the code added here).
…arking-rust-abi-unwind-issue-64655, r=alexcrichton Always mark rust and rust-call abi's as unwind PR rust-lang#63909 identified a bug that had been injected by PR rust-lang#55982. As discussed on rust-lang#64655 (comment) , we started marking extern items as nounwind, *even* extern items that said they were using "Rust" or "rust-call" ABI. This is a more targeted variant of PR rust-lang#63909 that fixes the above bug. Fix rust-lang#64655 ---- I personally suspect we will want PR rust-lang#63909 to land in the long-term But: * it is not certain that PR rust-lang#63909 *will* land, * more importantly, PR rust-lang#63909 almost certainly will not be backported to beta/stable. The identified bug was more severe than I think anyone realized (apart from perhaps @gnzlbg, as noted [here](rust-lang#63909 (comment))). Thus, I was motivated to write this PR, which fixes *just* the issue with extern rust/rust-call functions, and deliberately avoids injecting further deviation from current behavior (you can see further notes on this in the comments of the code added here).
…-abi-unwind-issue-64655, r=alexcrichton Always mark rust and rust-call abi's as unwind PR #63909 identified a bug that had been injected by PR #55982. As discussed on #64655 (comment) , we started marking extern items as nounwind, *even* extern items that said they were using "Rust" or "rust-call" ABI. This is a more targeted variant of PR #63909 that fixes the above bug. Fix #64655 ---- I personally suspect we will want PR #63909 to land in the long-term But: * it is not certain that PR #63909 *will* land, * more importantly, PR #63909 almost certainly will not be backported to beta/stable. The identified bug was more severe than I think anyone realized (apart from perhaps @gnzlbg, as noted [here](#63909 (comment))). Thus, I was motivated to write this PR, which fixes *just* the issue with extern rust/rust-call functions, and deliberately avoids injecting further deviation from current behavior (you can see further notes on this in the comments of the code added here).
…king-rust-abi-unwind-issue-64655, r=alexcrichton Always mark rust and rust-call abi's as unwind PR rust-lang#63909 identified a bug that had been injected by PR rust-lang#55982. As discussed on rust-lang#64655 (comment) , we started marking extern items as nounwind, *even* extern items that said they were using "Rust" or "rust-call" ABI. This is a more targeted variant of PR rust-lang#63909 that fixes the above bug. Fix rust-lang#64655 ---- I personally suspect we will want PR rust-lang#63909 to land in the long-term But: * it is not certain that PR rust-lang#63909 *will* land, * more importantly, PR rust-lang#63909 almost certainly will not be backported to beta/stable. The identified bug was more severe than I think anyone realized (apart from perhaps @gnzlbg, as noted [here](rust-lang#63909 (comment))). Thus, I was motivated to write this PR, which fixes *just* the issue with extern rust/rust-call functions, and deliberately avoids injecting further deviation from current behavior (you can see further notes on this in the comments of the code added here).
This was intended to land way back in 1.24, but it was backed out due to breakage which has long since been fixed. Prior to this PR a crate could panic and unwind past an
extern fn
boundary, but such behavior is UB. For example, this is undefined behavior:This PR changes the behavior of generated code to be sound-by-default. If an
extern fn
is unwound (panicked through) then it immediately aborts the program. Put another way, noextern fn
can unwind.The implementation in this PR is pretty simple because an unstable
#[unwind]
attribute could already be used to tweak the unwinding behavior. As a result this PR basically just switches the default from#[unwind]
to#[unwind(abort)]
for allextern fn
definitions.Closes #52652