Lexer is a `pub` type, so it feels wrong that its fields are just pub (I guess it wasn't exported initially), so let's minimize visibility.
Context: I am looking into extracting rust-lexer into a library, which can be shared by rust-analyzer and rustc. I hope that a simple interface like `fn next_token(src: &str) -> (TokenKind, usize)` would work, but to try this out I need to understand what is the current API of the lexer.
Rollup merge of #59639 - cuviper:ignore-uninhabited, r=eddyb
Never return uninhabited values at all
Functions with uninhabited return values are already marked `noreturn`,
but we were still generating return instructions for this. When running
with `-C passes=lint`, LLVM prints:
Unusual: Return statement in function with noreturn attribute
The LLVM manual makes a stronger statement about `noreturn` though:
> This produces undefined behavior at runtime if the function ever does
dynamically return.
We now emit an `abort` anywhere that would have tried to return an
uninhabited value.
Rollup merge of #59596 - LukasKalbertodt:fix-range-fmt, r=Kimundi
Forward formatter settings to bounds of `Range<T>` in `fmt::Debug` impl
Before this change, formatter settings were lost when printing a `Range`. For example, printing a `Range<f32>` with `{:.2?}` would not apply the precision modifier when printing the floats. Now the `Debug` impls look a bit more verbose, but modifier are not lost.
---
I assume the exact output of `Debug` impls in `std` cannot be relied on by users and thus can change, right?
Auto merge of #59619 - alexcrichton:wasi-fs, r=fitzgen
wasi: Implement more of the standard library
This commit fills out more of the `wasm32-unknown-wasi` target's standard library, notably the `std::fs` module and all of its internals. A few tweaks were made along the way to non-`fs` modules, but the last commit contains the bulk of the work which is to wire up all APIs to their equivalent on WASI targets instead of unconditionally returning "unsupported". After this some basic filesystem operations and such should all be working in WASI!
Auto merge of #59684 - Centril:rollup-n7pnare, r=Centril
Rollup of 6 pull requests
Successful merges:
- #59316 (Internal lints take 2)
- #59663 (Be more direct about borrow contract)
- #59664 (Updated the documentation of spin_loop and spin_loop_hint)
- #59666 (Updated the environment description in rustc.)
- #59669 (Reduce repetition in librustc(_lint) wrt. impl LintPass by using macros)
- #59677 (rustfix coverage: Skip UI tests with non-json error-format)
Rollup merge of #59677 - phansch:rustfix_coverage_handle_other_error_formats, r=oli-obk
rustfix coverage: Skip UI tests with non-json error-format
When using the `rustfix-coverage` flag, some tests currently fail
because they define a different error-format than `json`.
The current implementation crashes when encountering those tests. Since
we don't care about non-json test output when collecting the coverage
data, we handle those tests by returning an empty `Vec` instead.
Rollup merge of #59664 - DevQps:improve-yield-spinlock-docs, r=alexcrichton
Updated the documentation of spin_loop and spin_loop_hint
# Description
- Updated the description of `core::hints::spin_loop`
- Updated the description of `core::async::spin_loop_hint`
Both documentation is rewritten to better reflect when one should prefer using a busy-wait spin-loop (and the `spin_loop` and `spin_loop_hint` functions) over `yield_now`. It also dives a little bit deeper on what the function actually does.
Rollup merge of #59663 - matklad:borrow, r=dtolnay
Be more direct about borrow contract
I always was confused by the difference between Borrow and AsRef, despite the fact that I've read all available docs at least a dozen of times.
I finally grokked the difference between the two when I realized the Borrow invariant:
> If you implement Borrow, you **must** make sure that Eq, Ord and Hash implementations are equivalent for borrowed and owned data
My problem was that this invariant is not stated explicitly in documentation, and instead some vague and philosophical notions are used.
So I suggest to mention the requirements of `Borrow` very explicitly: instead of "use Borrow when X and use AsRef when Y", let's phrase this as `Borrow` differs from `AsRef` in `W`, so that's why `Borrow` is for `X` and `AsRef` is for `Y`.
Note that this change could be seen as tightening contract of the Borrow. Let's say Alice has written the following code:
impl Borrow<str> for Person {
fn borrow(&self) -> &str { self.first_name.as_str() }
}
```
Now Bob uses this `Person` struct, puts it into `HashMap` and tries to look it up using `&str` for the first name. Bob's code naturally fails.
The question is, who is to blame: Alice, who has written the impl, or Bob, who uses the HashMap. If I read the current docs literally, I would say that `Bob` is to blame: `Eq` and `Hash` bounds appear on HashMap, so it is the HashMap which requires that they are consistent. By using a type for which the `Borrow` impl does not yield well-behaved `Eq`, Bob is violating contract of HashMap.
If, as this PR proposes, we unconditionally require that Eq & friends for borrow should be valid, then the blame shifts to Alice, which I think is more reasonable.
Josh Stone [Wed, 3 Apr 2019 22:44:49 +0000 (15:44 -0700)]
Never return uninhabited values at all
Functions with uninhabited return values are already marked `noreturn`,
but we were still generating return instructions for this. When running
with `-C passes=lint`, LLVM prints:
Unusual: Return statement in function with noreturn attribute
The LLVM manual makes a stronger statement about `noreturn` though:
> This produces undefined behavior at runtime if the function ever does
dynamically return.
We now emit an `abort` anywhere that would have tried to return an
uninhabited value.
Philipp Hansch [Wed, 3 Apr 2019 19:30:57 +0000 (21:30 +0200)]
rustfix coverage: Skip UI tests with non-json error-format
When using the `rustfix-coverage` flag, some tests currently fail
because they define a different error-format than `json`.
The current implementation crashes when encountering those tests. Since
we don't care about non-json test output when collecting the coverage
data, we handle those tests by returning an empty `Vec` instead.
Alex Crichton [Fri, 29 Mar 2019 22:57:14 +0000 (15:57 -0700)]
wasi: Fill out `std::fs` module for WASI
This commit fills out the `std::fs` module and implementation for WASI.
Not all APIs are implemented, such as permissions-related ones and
`canonicalize`, but all others APIs have been implemented and very
lightly tested so far. We'll eventually want to run a more exhaustive
test suite!
For now the highlights of this commit are:
* The `std::fs::File` type is now backed by `WasiFd`, a raw WASI file
descriptor.
* All APIs in `std::fs` (except permissions/canonicalize) have
implementations for the WASI target.
* A suite of unstable extension traits were added to
`std::os::wasi::fs`. These traits expose the raw filesystem
functionality of WASI, namely `*at` syscalls (opening a file relative
to an already opened one, for example). Additionally metadata only
available on wasi is exposed through these traits.
Perhaps one of the most notable parts is the implementation of
path-taking APIs. WASI actually has no fundamental API that just takes a
path, but rather everything is relative to a previously opened file
descriptor. To allow existing APIs to work (that only take a path) WASI
has a few syscalls to learn about "pre opened" file descriptors by the
runtime. We use these to build a map of existing directory names to file
descriptors, and then when using a path we try to anchor it at an
already-opened file.
This support is very rudimentary though and is intended to be shared
with C since it's likely to be so tricky. For now though the C library
doesn't expose quite an API for us to use, so we implement it for now
and will swap it out as soon as one is available.
Auto merge of #59182 - hug-dev:armv8m-base-hf, r=alexcrichton
Add dist builder for Armv8-M Baseline and HF
This commit adds the Armv8-M Baseline and Armv8-M Mainline with
FPU targets in the list of targets that
get their dist components built. It also update the build-manifest
so that this target gets also its dist components uploaded.
Made possible with the recent change merged in `compiler-builtins`:
rust-lang-nursery/compiler-builtins#276
A new `compiler-builtins` might be necessary for successfull compilation of the artefacts of those targets.
Hugues de Valon [Tue, 12 Mar 2019 13:58:05 +0000 (13:58 +0000)]
Add dist builder for Armv8-M Baseline and HF
This commit adds the Armv8-M Baseline and Armv8-M Mainline with
FPU targets in the list of targets that
get their dist components built. It also update the build-manifest
so that this target gets also its dist components uploaded.
Rollup merge of #59514 - tmandry:remove-adt-def-from-projection-elem, r=eddyb
Remove adt_def from projections and downcasts in MIR
As part of optimizing generator layouts in MIR, we'd like to allow downcasting generators to variants which do not have a corresponding `def_id`, since they are created by the compiler.
This refactor hopes to allow that, without regressing perf.
Rollup merge of #59529 - DevQps:improve-rem-docs, r=cuviper
Added documentation on the remainder (Rem) operator for floating points.
# Description
As has been explained in #57738 the remainder operator on floating points is not clear.
This PR requests adds some information on how the `Rem` / remainder operator on floating points works.
Note also that this description is for both `Rem<f32> for f32` and `Rem<f64> for f64` implementations.
Ps. I wasn't really sure on how to formulate things. So please suggest changes if you have better idea's!
Rollup merge of #59446 - Aaron1011:fix/debuginfo-overflow, r=oli-obk
Fix stack overflow when generating debuginfo for 'recursive' type
By using 'impl trait', it's possible to create a self-referential
type as follows:
fn foo() -> impl Copy { foo }
This is a function which returns itself.
Normally, the signature of this function would be impossible
to write - it would look like 'fn foo() -> fn() -> fn() ...'
e.g. a function which returns a function, which returns a function...
Using 'impl trait' allows us to avoid writing this infinitely long
type. While it's useless for practical purposes, it does compile and run
However, issues arise when we try to generate llvm debuginfo for such a
type. All 'impl trait' types (e.g. ty::Opaque) are resolved when we
generate debuginfo, which can lead to us recursing back to the original
'fn' type when we try to process its return type.
To resolve this, I've modified debuginfo generation to account for these
kinds of weird types. Unfortunately, there's no 'correct' debuginfo that
we can generate - 'impl trait' does not exist in debuginfo, and this
kind of recursive type is impossible to directly represent.
To ensure that we emit *something*, this commit emits dummy
debuginfo/type names whenever it encounters a self-reference. In
practice, this should never happen - it's just to ensure that we can
emit some kind of debuginfo, even if it's not particularly meaningful
Rollup merge of #59166 - seanmonstar:trait-alias-import, r=alexreg
resolve: collect trait aliases along with traits
It seems trait aliases weren't being collected as `TraitCandidates` in resolve, this should change that. (I can't compile the full compiler locally, so relying on CI...)
- #59262 (Remove duplicated code from Iterator::{ne, lt, le, gt, ge})
- #59286 (Refactor async fn return type lowering)
- #59444 (Implement useful steps_between for all integers)
- #59452 (Speed up rustdoc run a bit)
- #59533 (Support allocating iterators with arenas)
- #59585 (Fixes for shallow borrows)
- #59607 (Renames `EvalErrorKind` to `InterpError`)
- #59613 (SGX target: convert a bunch of panics to aborts)
Rollup merge of #59613 - jethrogb:jb/waitqueue-wait-unwind, r=alexcrichton
SGX target: convert a bunch of panics to aborts
Fixes https://github.com/fortanix/rust-sgx/issues/86, https://github.com/fortanix/rust-sgx/issues/103 and in general protect preemptively against Iago attacks by aborting instead of unwinding in potentially unexpected situations.
Rollup merge of #59444 - cuviper:steps_between, r=scottmcm
Implement useful steps_between for all integers
We can use `usize::try_from` to convert steps from any size of integer.
This enables a meaningful `size_hint()` for larger ranges, rather than
always just `(0, None)`. Now they return the true `(len, Some(len))`
when it fits, otherwise `(usize::MAX, None)` for overflow.
Rollup merge of #59286 - cramertj:async-fn-ret-ty, r=varkor
Refactor async fn return type lowering
async fn now lowers directly to an existential type declaration
rather than reusing the `impl Trait` return type lowering.
As part of this, it lowers all argument-position elided lifetimes
using the in-band-lifetimes machinery, creating fresh parameter
names for each of them, using each lifetime parameter as a generic
argument to the generated existential type.
This doesn't currently successfully allow multiple
argument-position elided lifetimes since `existential type`
doesn't yet support multiple lifetimes where neither outlive
the other:
```rust
existential type Foo<'a, 'b>:; // error: ambiguous lifetime bound in `impl Trait`
fn foo<'a, 'b>(_: &'a u8, _: &'b u8) -> Foo<'a, 'b> { () }
```
Rollup merge of #59262 - timvermeulen:iterator_cmp_dedup, r=scottmcm
Remove duplicated code from Iterator::{ne, lt, le, gt, ge}
This PR delegates `Iterator::ne` to `Iterator::eq` and `Iterator::{lt, le, gt, ge}` to `Iterator::partial_cmp`.
Oddly enough, this change actually simplifies the generated assembly [in some cases](https://rust.godbolt.org/z/riBtNe), although I don't understand assembly well enough to see if the longer assembly is doing something clever.
I also added two extremely simple benchmarks:
```
// before
test iter::bench_lt ... bench: 98,404 ns/iter (+/- 21,008)
test iter::bench_partial_cmp ... bench: 62,437 ns/iter (+/- 5,009)
// after
test iter::bench_lt ... bench: 61,757 ns/iter (+/- 8,770)
test iter::bench_partial_cmp ... bench: 62,151 ns/iter (+/- 13,753)
```
I have no idea why the current `lt`/`le`/`gt`/`ge` implementations don't seem to be compiled optimally, but simply having them call `partial_cmp` seems to be an improvement.
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