Auto merge of #73645 - poliorcetics:ref-keyword, r=jyn514
Document the ref keyword
Partial fix for #34601.
This documents the `ref` keyword with two examples, one failing to compile because the `ref` keyword is missing, and the same example fixed with the keyword inserted in the correct place.
It also explains (very *very* rapidly) the differences between `&` and `ref`.
I put a link to the best place I could find in the Reference but there may be something better that I didn't find.
Auto merge of #74681 - RalfJung:miri-extern-fn, r=oli-obk
Miri: use extern fn to expose interpreter operations to program; fix leak checker on Windows
This PR realizes an idea that @oli-obk has been suggesting for a while: to use Miri-specific `extern` functions to provide some extra capabilities to the program. Initially, we have two of these methods, which libstd itself needs:
* `miri_start_panic`, which replaces the intrinsic of the same name (mostly for consistency, to avoid having multiple mechanisms for Miri-specific functionality).
* `miri_static_root`, which adds an allocation to a list of static "roots" that Miri considers as not having leaked (including all memory reachable through them). This is needed for https://github.com/rust-lang/miri/issues/1302.
We use `extern` functions instead of intrinsics for this so that user code can more easily call these Miri hoolks -- e.g. `miri_static_root` should be useful for https://github.com/rust-lang/miri/issues/1318.
The Miri side of this is at https://github.com/rust-lang/miri/pull/1485.
Auto merge of #74724 - Manishearth:rollup-plbt8fe, r=Manishearth
Rollup of 8 pull requests
Successful merges:
- #72954 (revise RwLock for HermitCore)
- #74367 (Rearrange the pipeline of `pow` to gain efficiency)
- #74491 (Optimize away BitAnd and BitOr when possible)
- #74639 (Downgrade glibc to 2.11.1 for ppc, ppc64 and s390x)
- #74661 (Refactor `region_name`: add `RegionNameHighlight`)
- #74692 (delay_span_bug instead of silent ignore)
- #74698 (fixed error reporting for mismatched traits)
- #74715 (Add a system for creating diffs across multiple mir optimizations.)
Rollup merge of #74661 - SNCPlay42:lifetime-names-refactor, r=estebank
Refactor `region_name`: add `RegionNameHighlight`
This PR does not change any diagnostics itself, rather it enables further code changes, but I would like to get approval for the refactoring first before making use of it.
In `rustc_mir::borrow_check::diagnostics::region_name`, there is code that allows for, when giving a synthesized name like `'1` to an anonymous lifetime, pointing at e.g. the exact '`&`' that introduces the lifetime.
This PR decouples that code from the specific case of arguments, adding a new enum `RegionNameHighlight`, enabling future changes to use it in other places.
This allows:
* We could change the other `AnonRegionFrom*` variants to use `RegionNameHighlight` to precisely point at where lifetimes are introduced in other locations when they have type annotations, e.g. a closure return `|...| -> &i32`.
* Because of how async functions are lowered this affects async functions as well, see #74072
* for #74597, we could add a second, optional `RegionNameHighlight` to the `AnonRegionFromArgument` variant that highlights a lifetime in the return type of a function when, due to elision, this is the same as the argument lifetime.
* in https://github.com/rust-lang/rust/issues/74497#issuecomment-6606229707 I noticed that a diagnostic was trying to introduce a lifetime `'2` in the opaque type `impl std::future::Future`. The code for the case of arguments has [code to handle cases like this](https://github.com/rust-lang/rust/blob/bbebe7351fcd29af1eb9a35e315369b15887ea09/src/librustc_mir/borrow_check/diagnostics/region_name.rs#L365) but not the others. This refactoring would allow the same code path to handle this.
* It might be appropriate to add another variant of `RegionNameHighlight` to say something like `lifetime '1 appears in the opaque type impl std::future::Future`.
These are quite a few changes so I thought I would make sure the refactoring is OK before I start making changes that rely on it. :)
Rollup merge of #74639 - msirringhaus:master, r=cuviper
Downgrade glibc to 2.11.1 for ppc, ppc64 and s390x
As discussed in #73782
I've tested these changes on rust 1.43.0 for all the specified archs and used the resulting binaries to bootstrap building rust 1.43.1.
I've also shortly tested these changes on master on ppc64.
Rollup merge of #74491 - xldenis:constant-binop-opt, r=oli-obk
Optimize away BitAnd and BitOr when possible
This PR lets `const_prop` optimize away `a | true == true` , `a & false == false` and `a * 0 = 0`. While I was writing this I've realized that constant propagation misses a lot of opportunities. For example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=2a4b45e772f214210a36749b27223bb0
Constant propagation doesn't seem to... propagate constants, additionally the way constant propagation is currently setup makes it tricky to add cases like `a | false == a`.
I tried to organize `eval_rvalue_with_identities` to make the pattern of the optimizations easier to see but it still obscurs what should be a simple peephole optmization.
Rollup merge of #74367 - Neutron3529:patch-1, r=nagisa
Rearrange the pipeline of `pow` to gain efficiency
The check of the `exp` parameter seems useless if we execute the while-loop more than once.
The original implementation of `pow` function using one more comparison if the `exp==0` and may break the pipeline of the cpu, which may generate a slower code.
The performance gap between the old and the new implementation may be small, but IMO, at least the newer one looks more beautiful.
---
bench prog:
```
#![feature(test)]
extern crate test;
#[macro_export]macro_rules! timing{
($a:expr)=>{let time=std::time::Instant::now();{$a;}print!("{:?} ",time.elapsed())};
($a:expr,$b:literal)=>{let time=std::time::Instant::now();let mut a=0;for _ in 0..$b{a^=$a;}print!("{:?} {} ",time.elapsed(),a)}
}
#[inline]
pub fn pow_rust(x:i64, mut exp: u32) -> i64 {
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
if exp == 1 {
acc = acc * base;
}
acc
}
#[inline]
pub fn pow_new(x:i64, mut exp: u32) -> i64 {
if exp==0{
1
}else{
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp >>= 1;
base = base * base;
}
acc * base
}
}
Auto merge of #74710 - JohnTitor:rollup-bdz4oee, r=JohnTitor
Rollup of 12 pull requests
Successful merges:
- #74361 (Improve doc theme logo display)
- #74504 (Add right border bar to Dark and Light theme)
- #74572 (Internally unify rustc_deprecated and deprecated)
- #74601 (Clean up E0724 explanation)
- #74623 (polymorphize GlobalAlloc::Function)
- #74665 (Don't ICE on unconstrained anonymous lifetimes inside associated types.)
- #74666 (More BTreeMap test cases, some exposing undefined behaviour)
- #74669 (Fix typo)
- #74677 (Remove needless unsafety from BTreeMap::drain_filter)
- #74680 (Add missing backticks in diagnostics note)
- #74694 (Clean up E0727 explanation)
- #74703 (Fix ICE while building MIR with type errors)
Rollup merge of #74703 - tmandry:issue-74047, r=oli-obk
Fix ICE while building MIR with type errors
See https://github.com/rust-lang/rust/issues/74047#issuecomment-663290913 for background. Replacing a binding with `PatKind::Wild` (introduced in #51789 and later refactored in #67439) caused an ICE downstream while building MIR.
I noticed that taking this code out no longer triggers the ICEs it was added to prevent. I'm not sure what else changed, or if this change is _correct_, but it does seem to be passing ui tests at least.
Rollup merge of #74677 - ssomers:btree_cleanup_2, r=Amanieu
Remove needless unsafety from BTreeMap::drain_filter
Remove one piece of unsafe code in the iteration over the iterator returned by BTreeMap::drain_filter.
- Changes an explicitly unspecified part of the API: when the user-supplied predicate (or some of BTreeMap's code) panicked, and the caller tries to use the iterator again, we no longer offer the same key/value pair to the predicate again but pretend the iterator has finished. Note that Miri does not find UB in the test case added here with the unsafe code (or without).
- Makes the code a little easier on the eyes.
- Makes the code a little harder on the CPU:
```
benchcmp c0 c2 --threshold 3
name c0 ns/iter c2 ns/iter diff ns/iter diff % speedup
btree::set::clone_100_and_drain_all 2,794 2,900 106 3.79% x 0.96
btree::set::clone_100_and_drain_half 2,604 2,964 360 13.82% x 0.88
btree::set::clone_10k_and_drain_half 287,770 322,755 34,985 12.16% x 0.89
```
r? @Amanieu
Rollup merge of #74665 - smmalis37:issue-62200, r=davidtwco
Don't ICE on unconstrained anonymous lifetimes inside associated types.
Fixes #62200. The change here is inspired (copied) by how this case is handled on bare fns at https://github.com/rust-lang/rust/blob/e8b55a4ad230ebec762fdfc4f241ba98a98560af/src/librustc_typeck/astconv.rs#L3083-L3106.
Rollup merge of #74572 - Mark-Simulacrum:unify-rustc-depr, r=petrochenkov
Internally unify rustc_deprecated and deprecated
This PR intentionally tries to be "featureless" in that the behavior is not altered for either attribute, though it more clearly exposes cases where that is the case in the code.
Auto merge of #74685 - ehuss:update-cargo, r=ehuss
Update cargo
21 commits in 43cf77395cad5b79887b20b7cf19d418bbd703a9..aa6872140ab0fa10f641ab0b981d5330d419e927
2020-07-13 17:35:42 +0000 to 2020-07-23 13:46:27 +0000
- Update features set in CI. (rust-lang/cargo#8530)
- Stabilize -Z crate-versions (rust-lang/cargo#8509)
- Fix typo in docs (rust-lang/cargo#8529)
- Remove unused CompileMode::all_modes (rust-lang/cargo#8526)
- Mask out system core.autocrlf settings before resetting git repos (rust-lang/cargo#8523)
- Flag git zlib errors as spurious errors (rust-lang/cargo#8520)
- Fix the help display for the target-triple option (rust-lang/cargo#8515)
- Check workspace member existence as dir. (rust-lang/cargo#8511)
- Bump to 0.48.0, update changelog (rust-lang/cargo#8508)
- Apply workspace.exclude to workspace.default-members. (rust-lang/cargo#8485)
- Fix nightly tests for intra-doc links. (rust-lang/cargo#8528)
- doc: Replace "regenerate" with "revoke" for API tokens (rust-lang/cargo#8510)
- Add back Manifest::targets_mut (rust-lang/cargo#8494)
- Build host dependencies with opt-level 0 by default (rust-lang/cargo#8500)
- Fix freshness checks for build scripts on renamed dirs (rust-lang/cargo#8497)
- Add a `-Zbuild-std-features` flag (rust-lang/cargo#8490)
- clippy cleanups (rust-lang/cargo#8495)
- Fix self-publish script. (rust-lang/cargo#8492)
- Ensure `unstable.build-std` works like `-Zbuild-std` (rust-lang/cargo#8491)
- Make `cargo metadata` output deterministic (rust-lang/cargo#8489)
- Switch to github actions (rust-lang/cargo#8467)
The current plan is to land this PR as a temporary change, so that we can get a better handle on the regressions introduced by it. Trying to fix/examine them in master is difficult, and we want to be better able to evaluate them without impact to other PRs being landed in the mean time.
That said, it is currently *my* belief that gimli, in one form or another, will need to land sometime soon. I think it's quite likely that it may slip a week or two, but I would personally push for re-landing it then "regardless" of the regressions. We should try to focus efforts on understanding and removing as much of the performance impact as possible, as everyone pretty much agrees that it should be quite minimal (and entirely in the linker, basically).
Auto merge of #74667 - Manishearth:rollup-s6k59sw, r=Manishearth
Rollup of 8 pull requests
Successful merges:
- #74141 (libstd/libcore: fix various typos)
- #74490 (add a Backtrace::disabled function)
- #74548 (one more Path::with_extension example, to demonstrate behavior)
- #74587 (Prefer constant over function)
- #74606 (Remove Linux workarounds for missing CLOEXEC support)
- #74637 (Make str point to primitive page)
- #74654 (require type defaults to be after const generic parameters)
- #74659 (Improve codegen for unchecked float casts on wasm)
Rollup merge of #74659 - alexcrichton:wasm-codegen, r=varkor
Improve codegen for unchecked float casts on wasm
This commit improves codegen for unchecked casts on WebAssembly targets
to use the singluar `iNN.trunc_fMM_{u,s}` instructions. Previously rustc
would codegen a bare `fptosi` and `fptoui` for float casts but for
WebAssembly targets the codegen for these instructions is quite large.
This large codegen is due to the fact that LLVM can speculate these
instructions so the trapping behavior of WebAssembly needs to be
protected against in case they're speculated.
The change here is to update the codegen for the unchecked cast
intrinsics to have a wasm-specific case where they call the appropriate
LLVM intrinsic to generate the right wasm instruction. The intrinsic is
explicitly opting-in to undefined behavior so a trap here for
out-of-bounds inputs on wasm should be acceptable.
Rollup merge of #74654 - lcnr:default-no-more, r=varkor
require type defaults to be after const generic parameters
From current discussions it seems like the goal here is for type and const parameters to be unordered and allow things like `struct Foo<const N: usize, T = u32>(T)` and `struct Foo<T, const N: usize = 7>` this way.
Note: This means that using `min_const_generics` it will not be possible for an adt to have both type defaults and const parameters.
Rollup merge of #74606 - cuviper:cloexec, r=sfackler
Remove Linux workarounds for missing CLOEXEC support
Now that #74163 updated the minimum Linux kernel to 2.6.32, we can
assume the availability of APIs that open file descriptors that are
already set to close on exec, including the flags `O_CLOEXEC`,
`SOCK_CLOEXEC`, and `F_DUPFD_CLOEXEC`.
Rearrange the pipeline of `pow` to gain efficiency
The check of the `exp` parameter seems useless if we execute the while-loop more than once.
The original implementation of `pow` function using one more comparison if the `exp==0` and may break the pipeline of the cpu, which may generate a slower code.
The performance gap between the old and the new implementation may be small, but IMO, at least the newer one looks more beautiful.
---
bench prog:
```
extern crate test;
($a:expr)=>{let time=std::time::Instant::now();{$a;}print!("{:?} ",time.elapsed())};
($a:expr,$b:literal)=>{let time=std::time::Instant::now();let mut a=0;for _ in 0..$b{a^=$a;}print!("{:?} {} ",time.elapsed(),a)}
}
pub fn pow_rust(x:i64, mut exp: u32) -> i64 {
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
if exp == 1 {
acc = acc * base;
}
acc
}
pub fn pow_new(x:i64, mut exp: u32) -> i64 {
if exp==0{
1
}else{
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp >>= 1;
base = base * base;
}
acc * base
}
}
Auto merge of #74662 - Manishearth:rollup-jdt7t71, r=Manishearth
Rollup of 9 pull requests
Successful merges:
- #73783 (Detect when `'static` obligation might come from an `impl`)
- #73868 (Advertise correct stable version for const control flow)
- #74460 (rustdoc: Always warn when linking from public to private items)
- #74538 (Guard against non-monomorphized type_id intrinsic call)
- #74541 (Add the aarch64-apple-darwin target )
- #74600 (Enable perf try builder)
- #74618 (Do not ICE on assoc type with bad placeholder)
- #74631 (rustc_target: Add a target spec option for disabling `--eh-frame-hdr`)
- #74643 (build: Remove unnecessary `cargo:rerun-if-env-changed` annotations)
rustc and cargo now track the majority of env var dependencies automatically (https://github.com/rust-lang/cargo/pull/8421), so the annotations are no longer necessary.
Rollup merge of #74631 - petrochenkov:ehdr2, r=jonas-schievink
rustc_target: Add a target spec option for disabling `--eh-frame-hdr`
Disable `--eh-frame-hdr` for targets that use an `ld`-like linker, but don't support that option.
Do it through a target spec option rather than through hard-coding in `linker.rs`.
The option is still enabled by default though.
cc https://github.com/rust-lang/rust/pull/73564
Fixes https://github.com/rust-lang/rust/pull/73564#issuecomment-657011004
Fixes https://github.com/rust-lang/rust/pull/74625
Fixes https://github.com/rust-embedded/msp430-rt/issues/12
Rollup merge of #74600 - Mark-Simulacrum:try-perf, r=pietroalbini
Enable perf try builder
This adds a dedicated branch for perf to use for CI, intended to allow perf to
enqueue builds without needing to use bors. bors is great, but bors requires an
open PR to work, and we want to invoke perf on closed PRs sometimes (in
particular, rollups).
Rollup merge of #74538 - nbdd0121:issue-73976, r=lcnr
Guard against non-monomorphized type_id intrinsic call
This PR checks whether the type is sufficient monomorphized when calling type_id or type_name intrinsics. If the type is not sufficiently monomorphized, e.g. used in a pattern, the code will be rejected.
Rollup merge of #74460 - dennis-hamester:rustdoc-warn-pub-to-priv, r=jyn514
rustdoc: Always warn when linking from public to private items
Change the logic such that linking from a public to a private item always triggers `intra_doc_link_resolution_failure`.
Previously, the warning was not emitted when `--document-private-items` is passed.
This came up during the discussion in https://github.com/rust-lang/rust/pull/74147#discussion_r452597901.
Alex Crichton [Wed, 22 Jul 2020 21:51:12 +0000 (14:51 -0700)]
Improve codegen for unchecked float casts on wasm
This commit improves codegen for unchecked casts on WebAssembly targets
to use the singluar `iNN.trunc_fMM_{u,s}` instructions. Previously rustc
would codegen a bare `fptosi` and `fptoui` for float casts but for
WebAssembly targets the codegen for these instructions is quite large.
This large codegen is due to the fact that LLVM can speculate these
instructions so the trapping behavior of WebAssembly needs to be
protected against in case they're speculated.
The change here is to update the codegen for the unchecked cast
intrinsics to have a wasm-specific case where they call the appropriate
LLVM intrinsic to generate the right wasm instruction. The intrinsic is
explicitly opting-in to undefined behavior so a trap here for
out-of-bounds inputs on wasm should be acceptable.
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