Rollup merge of #74927 - Lokathor:Lokathor-patch-1, r=jonas-schievink
Change the target data layout to specify more values
This does not actually alter the previously specified important parts, but apparently `rustc` cares about more layout components than `cargo-xbuild` ever did. This extends the data layout to be a fully specified layout, as given in the error from issue #74767
Rollup merge of #74869 - tmiasko:must-use-closures, r=ecstatic-morse
Make closures and generators a must use types
Warn about unused expressions with closure or generator type. This follows
existing precedence of must use annotations present on `FnOnce`, `FnMut`, `Fn`
traits, which already indirectly apply to closures in some cases, e.g.,:
```rust
fn f() -> impl FnOnce() {
|| {}
}
fn main() {
// an existing warning: unused implementer of `std::ops::FnOnce` that must be used:
f();
// a new warning: unused closure that must be used:
|| {};
}
```
Rollup merge of #74852 - lzutao:inline-rm-tostring, r=nnethercote
Explain why inlining default ToString impl
Trying to remove inline attribute from default ToString impl causes regression.
Perf result at <https://github.com/rust-lang/rust/pull/74852#issuecomment-664812994>.
Rollup merge of #74742 - poliorcetics:ip-addr-remove-rejected-errata, r=nikomatsakis
Remove links to rejected errata 4406 for RFC 4291
Fixes #74198.
For now I simply removed the links, the docs seems clear enough to me but I'm no expert in the domain so don't hesitate to correct me if more is needed.
Change the target data layout to specify more values
This does not actually alter the previously specified important parts, but apparently `rustc` cares about more layout components than `cargo-xbuild` ever did. This extends the data layout to be fully specified layout, as given in the error from issue #74767
Auto merge of #74733 - richkadel:llvm-coverage-map-gen-5, r=tmandry
Fixed coverage map issues; better aligned with LLVM APIs
Found some problems with the coverage map encoding when testing with more than one counter per function.
While debugging, I realized some better ways to structure the Rust implementation of the coverage mapping generator. I refactored somewhat, resulting in less code overall, expanded coverage of LLVM Coverage Map capabilities, and much closer alignment with LLVM data structures, APIs, and naming.
This should be easier to follow and easier to maintain.
r? @tmandry
Rust compiler MCP rust-lang/compiler-team#278
Relevant issue: #34701 - Implement support for LLVMs code coverage instrumentation
Auto merge of #74837 - xldenis:mir-dump-crate-file, r=oli-obk
Fix #70767
This PR changes the format of MIR dump filenames to include the crate name rather than `rustc` at the start.
As a result, we can now place mir-opt tests in the same directory as the source files, like with UI tests. I had to make sure that `compiletest` added a bit_width suffix to the expected files when appropriate but otherwise the change is only moving the files to the correct location and ensuring that the `EMIT_MIR` lines are correct.
Auto merge of #72488 - KodrAus:stabilize/const_type_id, r=nikomatsakis
Stabilize const_type_id feature
The tracking issue for `const_type_id` points to the ill-fated #41875. So I'm re-energizing `TypeId` shenanigans by opening this one up to see if there's anything blocking us from stabilizing the constification of type ids.
Will wait for CI before pinging teams/groups.
-----
This PR stabilizes the `const_type_id` feature, which allows `TypeId::of` (and the underlying unstable intrinsic) to be called in constant contexts.
There are some [sanity tests](https://github.com/rust-lang/rust/blob/master/src/test/ui/consts/const-typeid-of-rpass.rs) that demonstrate its usage, but I’ve included some more below.
As a simple example, you could create a constant item that contains some type ids:
`TypeId::of` is generic, which we saw above in the way the generic `Self` argument was used. This has some implications for const evaluation. It means we can make trait impls evaluate differently depending on information that wasn't directly passed through the trait system. This violates the _parametricity_ property, which requires all instances of a generic function to behave the same way with respect to its generic parameters. That's not unique to `TypeId::of`, other generic const functions based on compiler intrinsics like `mem::align_of` can also violate parametricity. In practice Rust doesn't really have type parametricity anyway since it monomorphizes generics into concrete functions, so violating it using type ids isn’t new.
As an example of how impls can behave differently, you could combine constant type ids with the `const_if_match` feature to dispatch calls based on the type id of the generic `Self`, rather than based on information about `Self` that was threaded through trait bounds. It's like a rough-and-ready form of specialization:
```rust
#![feature(const_if_match)]
trait Specialized where Self: 'static {
// An associated constant that determines the function to call
// at compile-time based on `TypeId::of::<Self>`.
const CALL: fn(&Self) = {
const USIZE: TypeId = TypeId::of::<usize>();
match TypeId::of::<Self>() {
// Use a closure for `usize` that transmutes the generic `Self` to
// a concrete `usize` and dispatches to `Self::usize`.
USIZE => |x| Self::usize(unsafe { &*(x as *const Self as *const usize) }),
// For other types, dispatch to the generic `Self::default`.
_ => Self::default,
}
};
fn call(&self) {
// Call the function we determined at compile-time
(Self::CALL)(self)
}
fn default(x: &Self);
fn usize(x: &usize);
}
// Implement our `Specialized` trait for any `Debug` type.
impl<T: fmt::Debug + 'static> Specialized for T {
fn default(x: &Self) {
println!("default: {:?}", x);
}
// Will print "usize: 42"
Specialized::call(&42usize);
// Will print "default: ()"
Specialized::call(&());
```
Type ids have some edges that this stabilization exposes to more contexts. It's possible for type ids to collide (but this is a bug). Since they can change between compiler versions, it's never valid to cast a type id to its underlying value.
Auto merge of #72049 - mati865:mingw-lld, r=petrochenkov
MinGW: enable dllexport/dllimport
Fixes (only when using LLD) https://github.com/rust-lang/rust/issues/50176
Fixes https://github.com/rust-lang/rust/issues/72319
This makes `windows-gnu` on pair with `windows-msvc` when it comes to symbol exporting.
For MinGW it means both good things like correctly working dllimport/dllexport, ability to link with LLD and bad things like https://github.com/rust-lang/rust/issues/27438.
Not sure but maybe this should land behind unstable compiler option (`-Z`) or environment variable?
Mateusz Mikuła [Thu, 7 May 2020 09:52:21 +0000 (11:52 +0200)]
MinGW: emit dllexport/dllimport by rustc
This fixes various cases where LD could not guess dllexport correctly and greatly improves compatibility with LLD which is not going to support linker scripts anytime soon
Auto merge of #74900 - tmiasko:doc-open, r=Mark-Simulacrum
Fix opening docs for std crates with ./x.py doc --open library/*
The directories for core, alloc, std, proc_macro, and test crates now
correspond directly to the crate name, and stripping the "lib" prefix is
no longer necessary.
Tomasz Miąsko [Wed, 29 Jul 2020 00:00:00 +0000 (00:00 +0000)]
Fix opening docs for std crates with ./x.py doc --open library/*
The directories for core, alloc, std, proc_macro, and test crates now
correspond directly to the crate name and stripping the "lib" prefix is
no longer necessary.
Auto merge of #74887 - Mark-Simulacrum:cache-non-exhaustive, r=petrochenkov
Cache non-exhaustive separately from attributes
This prevents cross-crate attribute loading from metadata just for non_exhaustive checking; cross-crate attribute loading implies disk reading and is relatively slow.
Rollup merge of #74872 - JohnTitor:ping-risc-v, r=Mark-Simulacrum
Enable to ping RISC-V group via triagebot
We have the RISC-V group (https://github.com/rust-lang/team/blob/master/teams/risc-v.toml) but don't enable to ping on this repository (https://github.com/rust-lang/rust/pull/74813#issuecomment-664841177).
We don't have the instructions on the rustc-dev-guide yet but I'll create it soonish.
Auto merge of #74791 - tmiasko:raw-waker-inline, r=LukasKalbertodt
Add #[inline] to RawWaker::new
`RawWaker::new` is used when creating a new waker or cloning an existing one,
for example as in code below. The `RawWakerVTable::new` can be const evaluated,
but `RawWaker::new` itself cannot since waker pointer is not known at compile
time. Add `#[inline]` to avoid overhead of a function call.
Auto merge of #74482 - alexcrichton:update-stdarch, r=hanna-kruppe
Update stdarch submodule
This commit updates the src/stdarch submodule primarily to include
rust-lang/stdarch#874 which updated and revamped WebAssembly SIMD
intrinsics and renamed WebAssembly atomics intrinsics. This is all
unstable surface area of the standard library so the changes should be
ok here. The SIMD updates also enable SIMD intrinsics to be used by any
program any any time, yay!
cc #74372, a tracking issue I've opened for the stabilization of SIMD
intrinsics
Alex Crichton [Sat, 18 Jul 2020 15:43:09 +0000 (08:43 -0700)]
Update stdarch submodule
This commit updates the src/stdarch submodule primarily to include
rust-lang/stdarch#874 which updated and revamped WebAssembly SIMD
intrinsics and renamed WebAssembly atomics intrinsics. This is all
unstable surface area of the standard library so the changes should be
ok here. The SIMD updates also enable SIMD intrinsics to be used by any
program any any time, yay!
cc #74372, a tracking issue I've opened for the stabilization of SIMD
intrinsics
Auto merge of #73964 - jyn514:sane-defaults, r=Mark-Simulacrum
Improve defaults in x.py
- Make the default stage dependent on the subcommand
- Don't build stage1 rustc artifacts with x.py build --stage 1. If this is what you want, use x.py build --stage 2 instead, which gives you a working libstd.
- Change default debuginfo when debug = true from 2 to 1
I tried to fix CI to use `--stage 2` everywhere it currently has no stage, but I might have missed a spot.
This does not update much of the documentation - most of it is in https://github.com/rust-lang/rustc-dev-guide/ or https://github.com/rust-lang/rust-forge and will need a separate PR.
See individual commits for a detailed rationale of each change.
See also the MCP: https://github.com/rust-lang/compiler-team/issues/326
r? @Mark-Simulacrum , but anyone is free to give an opinion.
Auto merge of #74796 - infinity0:master, r=nikomatsakis
config.toml.example: Update remap-debuginfo doc to be more general & accurate
This makes it more obvious that the work-around to #74786 is actually correct, and a custom `--remap-path-prefix` isn't needed.
In fact the previous comment `/rustc/$hash/$crate` was wrong, it is not `$crate` but whatever path exists in the rustc source tree, so either `src/$crate` or `vendor/$crate`. I've fixed that as well to avoid future confusion.
Auto merge of #74855 - jyn514:separate-lints, r=Manishearth
Separate `missing_doc_code_examples` from intra-doc links
These two lints have no relation other than both being nightly-only.
This allows stabilizing intra-doc links without stabilizing `missing_doc_code_examples`.
Fixes one of the issues spotted by @ollie27 in https://github.com/rust-lang/rust/pull/74430#issuecomment-664693080.
Joshua Nelson [Mon, 27 Jul 2020 19:53:01 +0000 (15:53 -0400)]
Add assert that tests happen with stage 2 in CI
- Use stage 2 for makefile
- Move assert to builder
- Don't add an assert for --help
- Allow --stage 0 if passed explicitly
- Don't assert defaults during tests
> Linking seems to consume all available RAM, leading to the OS to swap memory to disk and slowing down everything in the process
Compiling itself doesn't seem to take up as much RAM, and I'm only looking to check whether a minimal testcase can be compiled by rustc, where the runtime performance isn't much of an issue
> do you have debug = true or debuginfo-level = 2 in config.toml?
> if so I think that results in over 2GB of debuginfo nowadays and is likely the culprit
> which might mean we're giving out bad advice :(
Anecdotally, this sped up my stage 1 build from 15 to 10 minutes.
This still adds line numbers, it only removes variable and type information.
This leaves you with a broken stage2 rustc which doesn't even have
libcore and is effectively useless. Additionally, it compiles rustc
twice, which is not normally what you want.
This is suitable for contributors working on the compiler. It ensures
that you have a working rustc and libstd without having to pass
`src/libstd` in addition.
This is suitable for CI, which wants all tools in release mode.
However, most of the use cases for this should use `x.py dist` instead,
which builds all the tools without each having to be named individually.
Joshua Nelson [Thu, 2 Jul 2020 12:08:09 +0000 (08:08 -0400)]
Make the default stage dependent on the subcommand
### x.py build/test: stage 1
I've seen very few people who actually use full stage 2 builds on purpose. These compile rustc and libstd twice and don't give you much more information than a stage 1 build (except in rare cases like https://github.com/rust-lang/rust/pull/68692#discussion_r376392145). For new contributors, this makes the build process even more daunting than it already is. As long as CI is changed to use `--stage 2` I see no downside here.
### x.py bench/dist/install: stage 2
These commands have to do with a finished, optimized version of rustc. It seems very rare to want to use these with a stage 1 build.
### x.py doc: stage 0
Normally when you document things you're just fixing a typo. In this case there is no need to build the whole rust compiler, since the documentation will usually be the same when generated with the beta compiler or with stage 1.
Note that for this release cycle only there will be a significant different between stage0 and stage1 docs: https://github.com/rust-lang/rust/pull/73101. However most of the time this will not be the case.
Joshua Nelson [Tue, 28 Jul 2020 02:16:41 +0000 (22:16 -0400)]
Separate `missing_doc_code_examples` from intra-doc links
These two lints have no relation other than both being nightly-only.
This allows stabilizing intra-doc links without stabilizing
missing_doc_code_examples.
Auto merge of #73265 - mark-i-m:mv-std, r=Mark-Simulacrum,mark-i-m
mv std libs to library/
This is the first step in refactoring the directory layout of this repository, with further followup steps planned (but not done yet).
Background: currently, all crates are under src/, without nested src directories and with the unconventional `lib*` prefixes (e.g., `src/libcore/lib.rs`). This directory structures is not idiomatic and makes the `src/` directory rather overwhelming. To improve contributor experience and make things a bit more approachable, we are reorganizing the repo a bit.
In this PR, we move the standard libs (basically anything that is "runtime", as opposed to part of the compiler, build system, or one of the tools, etc). The new layout moves these libraries to a new `library/` directory in the root of the repo. Additionally, we remove the `lib*` prefixes and add nested `src/` directories. The other crates/tools in this repo are not touched. So in summary:
```
library/<crate>/src/*.rs
src/<all the rest> // unchanged
```
where `<crate>` is:
- core
- alloc
- std
- test
- proc_macro
- panic_abort
- panic_unwind
- profiler_builtins
- term
- unwind
- rtstartup
- backtrace
- rustc-std-workspace-*
There was a lot of discussion about this and a few rounds of compiler team approvals, FCPs, MCPs, and nominations. The original MCP is https://github.com/rust-lang/compiler-team/issues/298. The final approval of the compiler team was given here: https://github.com/rust-lang/rust/pull/73265#issuecomment-659498446.
The name `library` was chosen to complement a later move of the compiler crates to a `compiler/` directory. There was a lot of discussion around adding the nested `src/` directories. Note that this does increase the nesting depth (plausibly important for manual traversal of the tree, e.g., through GitHub's UI or `cd`), but this is deemed to be better as it fits the standard layout of Rust crates throughout most of the ecosystem, though there is some debate about how much this should apply to multi-crate projects. Overall, there seem to be more people in favor of nested `src/` than against.
After this PR, there are no dependencies out of the `library/` directory except on the `build_helper` (or crates.io crates).
Tomasz Miąsko [Tue, 28 Jul 2020 00:00:00 +0000 (00:00 +0000)]
Make closures and generators a must use types
Warn about unused expressions with closure or generator type. This follows
existing precedence of must use annotations present on `FnOnce`, `FnMut`, `Fn`
traits, which already indirectly apply to closures in some cases, e.g.,:
```rust
fn f() -> impl FnOnce() {
|| {}
}
fn main() {
// an existing warning: unused implementer of `std::ops::FnOnce` that must be used:
f();
// a new warning: unused closure that must be used:
|| {};
}
```
Now that `#[track_caller]` is on track to stabilize, one of the roughest edges of working with it is the fact that you can't do much with `Location` except turn it back into a `(&str, u32, u32)`. Which makes sense because the type was defined around the panic machinery originally passing around that tuple (it has the same layout as Location even).
This PR derives common traits for the type in accordance with the [API guidelines](https://rust-lang.github.io/api-guidelines/interoperability.html#types-eagerly-implement-common-traits-c-common-traits) (those apply to core, right?).
There's a risk here, e.g. if we ever change the representation of `Location` in a way that makes it harder to implement `Ord`, we might not be able to make that change in a backwards-compatible way. I don't think there's any other compatibility hazard here, as the only changes we currently imagine for the type are to add end fields.