bors [Tue, 27 Oct 2020 11:43:18 +0000 (11:43 +0000)]
Auto merge of #78227 - SergioBenitez:test-stdout-threading, r=m-ou-se
Capture output from threads spawned in tests
This is revival of #75172.
Original text:
> Fixes #42474.
>
> r? `@dtolnay` since you expressed interest in this, but feel free to redirect if you aren't the right person anymore.
bors [Tue, 27 Oct 2020 09:25:54 +0000 (09:25 +0000)]
Auto merge of #77502 - varkor:const-generics-suggest-enclosing-braces, r=petrochenkov
Suggest that expressions that look like const generic arguments should be enclosed in brackets
I pulled out the changes for const expressions from https://github.com/rust-lang/rust/pull/71592 (without the trait object diagnostic changes) and made some small changes; the implementation is `@estebank's.`
We're also going to want to make some changes separately to account for trait objects (they result in poor diagnostics, as is evident from one of the test cases here), such as an adaption of https://github.com/rust-lang/rust/pull/72273.
Yuki Okushi [Mon, 26 Oct 2020 23:45:24 +0000 (08:45 +0900)]
Rollup merge of #78396 - josephlr:ermsb, r=petrochenkov
Add compiler support for LLVM's x86_64 ERMSB feature
This change is needed for compiler-builtins to check for this feature
when implementing memcpy/memset. See:
https://github.com/rust-lang/compiler-builtins/pull/365
Without this change, the following code compiles, but does nothing:
```rust
#[cfg(target_feature = "ermsb")]
pub unsafe fn ermsb_memcpy() { ... }
```
The change just does compile-time detection. I think that runtime
detection will have to come in a follow-up CL to std-detect.
Like all the CPU feature flags, this just references #44839
Yuki Okushi [Mon, 26 Oct 2020 23:44:57 +0000 (08:44 +0900)]
Rollup merge of #78342 - oliviacrain:checkmate-pass, r=Mark-Simulacrum
Use check-pass in single-use-lifetime ui tests
Rationale: the `single_use_lifetimes` lint is used during late name resolution, which is within the scope of `check-pass` and does not require codegen or linking.
Helps remove some FIXMES associated with #62277. Additionally tidies touched test files.
Yuki Okushi [Mon, 26 Oct 2020 23:44:41 +0000 (08:44 +0900)]
Rollup merge of #76635 - scottmcm:slice-as-chunks, r=LukasKalbertodt
Add [T]::as_chunks(_mut)
Allows getting the slices directly, rather than just through an iterator as in `array_chunks(_mut)`. The constructors for those iterators are then written in terms of these methods, so the iterator constructors no longer have any `unsafe` of their own.
bors [Mon, 26 Oct 2020 23:22:39 +0000 (23:22 +0000)]
Auto merge of #77876 - tmiasko:simplify-locals, r=wesleywiser
Remove unused set-discriminant statements and assignments regardless of rvalue
* Represent use counts with u32
* Unify use count visitors
* Change RemoveStatements visitor into a function
* Remove unused set-discriminant statements
* Use exhaustive match to clarify what is being optimized
* Remove unused assignments regardless of rvalue kind
bors [Mon, 26 Oct 2020 18:50:22 +0000 (18:50 +0000)]
Auto merge of #68965 - eddyb:mir-inline-scope, r=nagisa,oli-obk
rustc_mir: track inlined callees in SourceScopeData.
We now record which MIR scopes are the roots of *other* (inlined) functions's scope trees, which allows us to generate the correct debuginfo in codegen, similar to what LLVM inlining generates.
This PR makes the `ui` test `backtrace-debuginfo` pass, if the MIR inliner is turned on by default.
Also, `#[track_caller]` is now correct in the face of MIR inlining (cc `@anp).`
bors [Mon, 26 Oct 2020 16:31:38 +0000 (16:31 +0000)]
Auto merge of #77975 - bjorn3:cg_clif_subtree3, r=Mark-Simulacrum
Add cg_clif as optional codegen backend
Rustc_codegen_cranelift is an alternative codegen backend for rustc based on Cranelift. It has the potential to improve compilation times in debug mode. In my experience the compile time improvements over debug mode LLVM for a clean build are about 20-30% in most cases.
This PR adds cg_clif as optional codegen backend. By default it is only enabled for `./x.py check`. It can be enabled for `./x.py build` too by adding `cranelift` to the `rust.codegen-backends` array in `config.toml`.
bors [Mon, 26 Oct 2020 11:56:59 +0000 (11:56 +0000)]
Auto merge of #78196 - pietroalbini:shipped-files, r=Mark-Simulacrum
Allow creating a list of files shipped in a release
This PR adds the `BUILD_MANIFEST_SHIPPED_FILES_PATH` environment variable to `build-manifest`, which writes a list of all the files referenced in the manifest to the path defined in the variable. The use for this is for `promote-release` to prune files unused files before publishing a release.
This PR **does not implement any pruning**, it just adds support for it to be implemented in the future on `promote-release`'s side.
Joe Richey [Mon, 26 Oct 2020 10:46:54 +0000 (03:46 -0700)]
Add compiler support for LLVM's x86 ERMSB feature
This change is needed for compiler-builtins to check for this feature
when implementing memcpy/memset. See:
https://github.com/rust-lang/compiler-builtins/pull/365
The change just does compile-time detection. I think that runtime
detection will have to come in a follow-up CL to std-detect.
Like all the CPU feature flags, this just references #44839
Update affected ui & incremental tests to use a user declared variable
bindings instead of temporaries. The former are preserved because of
debuginfo, the latter are not.
Tomasz Miąsko [Thu, 22 Oct 2020 00:00:00 +0000 (00:00 +0000)]
simplify-locals: Unify use count visitors
The simplify locals implementation uses two different visitors to update
the locals use counts. The DeclMarker calculates the initial use counts.
The StatementDeclMarker updates the use counts as statements are being
removed from the block.
Replace them with a single visitor that can operate in either mode,
ensuring consistency of behaviour.
Additionally use exhaustive match to clarify what is being optimized.
This still looks very good, but LLVM does not really translate that to
what would be considered ideal machine code (on any target). For example
that's the codegen we obtain for an unknown alignment:
; x86_64
dec rsi
mov rax, rdi
neg rax
and rax, rsi
add rax, rdi
In particular negating a pointer is not something that’s going to be
optimised for in the design of CISC architectures like x86_64. They
are much better at offsetting pointers. And so we’d love to utilize this
ability and produce code that's more like this:
To achieve this we need to give LLVM an opportunity to apply its
various peep-hole optimisations that it does during DAG selection. In
particular, the `and` instruction appears to be a major inhibitor here.
We cannot, sadly, get rid of this load-bearing operation, but we can
reorder operations such that LLVM has more to work with around this
instruction.
One such ordering is proposed in #75579 and results in LLVM IR that
looks broadly like this:
; using add enables `lea` and similar CISCisms
%offset_ptr = add i64 %address, %a_minus_one
%mask = sub i64 0, %a
%masked = and i64 %offset_ptr, %mask
; can be folded with `gepi` that may follow
%offset = sub i64 %masked, %address
…and generates the intended x86_64 machine code.
One might also wonder how the increased amount of code would impact a
RISC target. Turns out not much:
; aarch64 previous ; aarch64 new
sub x8, x1, #1 add x8, x1, x0
neg x9, x0 sub x8, x8, #1
and x8, x9, x8 neg x9, x1
add x0, x0, x8 and x0, x8, x9
(and similarly for ppc, sparc, mips, riscv, etc)
The only target that seems to do worse is… wasm32.
Onto actual measurements – the best way to evaluate snipets like these
is to use llvm-mca. Much like Aarch64 assembly would allow to suspect,
there isn’t any performance difference to be found. Both snippets
execute in same number of cycles for the CPUs I tried. On x86_64,
we get throughput improvement of >50%!
bors [Mon, 26 Oct 2020 04:34:46 +0000 (04:34 +0000)]
Auto merge of #78387 - Dylan-DPC:rollup-ch0st6z, r=Dylan-DPC
Rollup of 10 pull requests
Successful merges:
- #74477 (`#[deny(unsafe_op_in_unsafe_fn)]` in sys/wasm)
- #77836 (transmute_copy: explain that alignment is handled correctly)
- #78126 (Properly define va_arg and va_list for aarch64-apple-darwin)
- #78137 (Initialize tracing subscriber in compiletest tool)
- #78161 (Add issue template link to IRLO)
- #78214 (Tweak match arm semicolon removal suggestion to account for futures)
- #78247 (Fix #78192)
- #78252 (Add codegen test for #45964)
- #78268 (Do not try to report on closures to avoid ICE)
- #78295 (Add some regression tests)
Dylan DPC [Mon, 26 Oct 2020 02:09:06 +0000 (03:09 +0100)]
Rollup merge of #78214 - estebank:match-semicolon, r=oli-obk
Tweak match arm semicolon removal suggestion to account for futures
* Tweak and extend "use `.await`" suggestions
* Suggest removal of semicolon on prior match arm
* Account for `impl Future` when suggesting semicolon removal
* Silence some errors when encountering `await foo()?` as can't be certain what the intent was
*Thanks to https://twitter.com/a_hoverbear/status/1318960787105353728 for pointing this out!*
bors [Sun, 25 Oct 2020 11:35:26 +0000 (11:35 +0000)]
Auto merge of #78350 - JohnTitor:rollup-vbbm5wf, r=JohnTitor
Rollup of 8 pull requests
Successful merges:
- #77984 (Compute proper module parent during resolution)
- #78085 (MIR validation should check `SwitchInt` values are valid for the type)
- #78208 (replace `#[allow_internal_unstable]` with `#[rustc_allow_const_fn_unstable]` for `const fn`s)
- #78209 (Update `compiler_builtins` to 0.1.36)
- #78276 (Bump backtrace-rs to enable Mach-O support on iOS.)
- #78320 (Link to cargo's `build-std` feature instead of `xargo` in custom target docs)
- #78322 (BTreeMap: stop mistaking node::MIN_LEN for a node level constraint)
- #78326 (Split out statement attributes changes from #78306)
Yuki Okushi [Sun, 25 Oct 2020 09:43:49 +0000 (18:43 +0900)]
Rollup merge of #78326 - Aaron1011:fix/min-stmt-lints, r=petrochenkov
Split out statement attributes changes from #78306
This is the same as PR https://github.com/rust-lang/rust/pull/78306, but `unused_doc_comments` is modified to explicitly ignore statement items (which preserves the current behavior).
This shouldn't have any user-visible effects, so it can be landed without lang team discussion.
---------
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
Yuki Okushi [Sun, 25 Oct 2020 09:43:47 +0000 (18:43 +0900)]
Rollup merge of #78322 - ssomers:btree_no_min_len_at_node_level, r=Mark-Simulacrum
BTreeMap: stop mistaking node::MIN_LEN for a node level constraint
Correcting #77612 that fell into the trap of assuming that node::MIN_LEN is an imposed minimum everywhere, and trying to make it much more clear it is an offered minimum at the node level.
Yuki Okushi [Sun, 25 Oct 2020 09:43:44 +0000 (18:43 +0900)]
Rollup merge of #78276 - cutsoy:bump-backtrace, r=nagisa
Bump backtrace-rs to enable Mach-O support on iOS.
Related to rust-lang/backtrace-rs#378. Fixes backtraces on iOS that were missing in Rust v1.47.0 after switching to gimli because it only enabled Mach-O support on macOS.
Yuki Okushi [Sun, 25 Oct 2020 09:43:42 +0000 (18:43 +0900)]
Rollup merge of #78209 - JohnTitor:compiler-builtins, r=Amanieu
Update `compiler_builtins` to 0.1.36
So, the libc build with cargo's `build-std` feature emits a lot of warnings like:
```
warning: a method with this name may be added to the standard library in the future
--> /home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.35/src/int/udiv.rs:98:23
|
98 | q = n << (<$ty>::BITS - sr);
| ^^^^^^^^^^^
...
268 | udivmod_inner!(n, d, rem, u128)
| ------------------------------- in this macro invocation
|
= warning: once this method is added to the standard library, the ambiguity may cause an error or change in behavior!
= note: for more information, see issue #48919 <rust-lang/rust/issues/48919>
= help: call with fully qualified syntax `Int::BITS(...)` to keep using the current method
= help: add `#![feature(int_bits_const)]` to the crate attributes to enable `num::<impl u128>::BITS`
= note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
```
(You can find the full log in https://github.com/rust-lang/libc/runs/1283695796?check_suite_focus=true for example.)
0.1.36 contains https://github.com/rust-lang/compiler-builtins/pull/332 so this version should remove this warning.
Yuki Okushi [Sun, 25 Oct 2020 09:43:40 +0000 (18:43 +0900)]
Rollup merge of #78208 - liketechnik:issue-69399, r=oli-obk
replace `#[allow_internal_unstable]` with `#[rustc_allow_const_fn_unstable]` for `const fn`s
`#[allow_internal_unstable]` is currently used to side-step feature gate and stability checks.
While it was originally only meant to be used only on macros, its use was expanded to `const fn`s.
This pr adds stricter checks for the usage of `#[allow_internal_unstable]` (only on macros) and introduces the `#[rustc_allow_const_fn_unstable]` attribute for usage on `const fn`s.
This pr does not change any of the functionality associated with the use of `#[allow_internal_unstable]` on macros or the usage of `#[rustc_allow_const_fn_unstable]` (instead of `#[allow_internal_unstable]`) on `const fn`s (see https://github.com/rust-lang/rust/issues/69399#issuecomment-712911540).
Note: The check for `#[rustc_allow_const_fn_unstable]` currently only validates that the attribute is used on a function, because I don't know how I would check if the function is a `const fn` at the place of the check. I therefore openend this as a 'draft pull request'.
bors [Sun, 25 Oct 2020 09:23:45 +0000 (09:23 +0000)]
Auto merge of #77476 - tgnottingham:buffered_siphasher128, r=nnethercote
perf: buffer SipHasher128
This is an attempt to improve Siphasher128 performance by buffering input. Although it reduces instruction count, I'm not confident the effect on wall times, or lack-thereof, is worth the change.
---
Additional notes not reflected in source comments:
* Implementation choices were guided by a combination of results from rustc-perf and micro-benchmarks, mostly the former.
* ~~I tried a couple of different struct layouts that might be more cache friendly with no obvious effect.~~ Update: a particular struct layout was chosen, but it's not critical to performance. See comments in source and discussion below.
* I suspect that buffering would be important to a SIMD-accelerated algorithm, but from what I've read and my own tests, SipHash does not seem very amenable to SIMD acceleration, at least by SSE.
bors [Sun, 25 Oct 2020 04:48:37 +0000 (04:48 +0000)]
Auto merge of #77398 - wesleywiser:measureme_0_8, r=Mark-Simulacrum
Upgrade to measureme 9.0.0
I believe I did this correctly but there's still a reference to `measureme@0.7.1` coming from `rustc-ap-rustc_data_structures` and I'm not sure how to resolve that.
r? `@Mark-Simulacrum`
We'll also need to deploy the new version of the tools on perf.rlo.
bors [Sun, 25 Oct 2020 02:27:09 +0000 (02:27 +0000)]
Auto merge of #77526 - RalfJung:dont-promote-unions, r=lcnr
stop promoting union field accesses in 'const'
Turns out that promotion of union field accesses is the only difference between "promotion in `const`/`static` bodies" and "explicit promotion". So if we can remove this, we have finally achieved what I thought to already be the case -- that the bodies of `const`/`static` initializers behave the same as explicit promotion contexts.
The reason we do not want to promote union field accesses is that they can introduce UB, i.e., they can go wrong. We want to [minimize the ways promoteds can fail to evaluate](https://github.com/rust-lang/const-eval/issues/53). Also this change makes things more consistent overall, removing a special case that was added without much consideration (as far as I can tell).