`rustc` whether to link its own C runtime and libraries or to rely on a external
linker to find them. (Supported only on `windows-gnu`, `linux-musl`, and `wasi` platforms.)
- [You can now use `-C target-feature=+crt-static` on `linux-gnu` targets.][77386]
+ Note: If you're using cargo you must explicitly pass the `--target` flag.
- [Added tier 2\* support for `aarch64-unknown-linux-musl`.][76420]
\* Refer to Rust's [platform support page][forge-platform-support] for more
- [`mem::uninitialized` will now panic if any inner types inside a struct or enum
disallow zero-initialization.][71274]
- [`#[target_feature]` will now error if used in a place where it has no effect.][78143]
+- [Foreign exceptions are now caught by `catch_unwind` and will cause an abort.][70212]
+ Note: This behaviour is not guaranteed and is still considered undefined behaviour,
+ see the [`catch_unwind`] documentation for further information.
+
-[78143]: https://github.com/rust-lang/rust/issues/78143
Internal Only
-------------
+These changes provide no direct user facing benefits, but represent significant
+improvements to the internals and overall performance of rustc and
+related tools.
+
- [Building `rustc` from source now uses `ninja` by default over `make`.][74922]
You can continue building with `make` by setting `ninja=false` in
your `config.toml`.
+- [cg_llvm: `fewer_names` in `uncached_llvm_type`][76030]
+- [Made `ensure_sufficient_stack()` non-generic][76680]
+[78143]: https://github.com/rust-lang/rust/issues/78143
+[76680]: https://github.com/rust-lang/rust/pull/76680/
+[76030]: https://github.com/rust-lang/rust/pull/76030/
+[70212]: https://github.com/rust-lang/rust/pull/70212/
[27675]: https://github.com/rust-lang/rust/issues/27675/
[54121]: https://github.com/rust-lang/rust/issues/54121/
[71274]: https://github.com/rust-lang/rust/pull/71274/
[73461]: https://github.com/rust-lang/rust/pull/73461/
[73166]: https://github.com/rust-lang/rust/pull/73166/
[intradoc-links]: https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html
+[`catch_unwind`]: https://doc.rust-lang.org/std/panic/fn.catch_unwind.html
[`Option::is_some`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some
[`Option::is_none`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none
[`Option::as_ref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_ref
Internal Only
--------
+
- [Improved default settings for bootstrapping in `x.py`.][73964] You can read details about this change in the ["Changes to `x.py` defaults"](https://blog.rust-lang.org/inside-rust/2020/08/30/changes-to-x-py-defaults.html) post on the Inside Rust blog.
[1.47.0-cfg]: https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard