bors [Fri, 13 Nov 2020 14:53:55 +0000 (14:53 +0000)]
Auto merge of #79017 - GuillaumeGomez:rollup-5orhudd, r=GuillaumeGomez
Rollup of 6 pull requests
Successful merges:
- #77151 (Add regression test for issue #76042)
- #77996 (Doc change: Remove mention of `fnv` in HashMap)
- #78463 (Add type to `ConstKind::Placeholder`)
- #78984 (Rustdoc check option)
- #78985 (add dropck test for const params)
- #78996 (add explicit test for const param promotion)
Guillaume Gomez [Fri, 13 Nov 2020 14:26:10 +0000 (15:26 +0100)]
Rollup merge of #77996 - tkaitchuck:master, r=m-ou-se
Doc change: Remove mention of `fnv` in HashMap
Disclaimer: I am the author of [aHash](https://github.com/tkaitchuck/aHash).
This changes the Rustdoc in `HashMap` from mentioning the `fnv` crate to mentioning the `aHash` crate, as an alternative `Hasher` implementation.
### Why
Fnv [has poor hash quality](https://github.com/rurban/smhasher), is [slow for larger keys](https://github.com/tkaitchuck/aHash/blob/master/compare/readme.md#speed), and does not provide dos resistance, because it is unkeyed (this can also cause [other problems](https://accidentallyquadratic.tumblr.com/post/153545455987/rust-hash-iteration-reinsertion)).
Fnv has acceptable performance for integers and has very poor performance with keys >32 bytes. This is the reason it was removed from the standard library in https://github.com/rust-lang/rust/pull/37229 .
Because regardless of which dimension you value, there are better alternatives, it does not make sense for anyone to consider using `fnv`.
The text mentioning `fnv` in the standard library continues to create confusion: https://github.com/rust-lang/hashbrown/issues/153 https://github.com/rust-lang/hashbrown/issues/9 . There are also a number of [crates using it](https://crates.io/crates/fnv/reverse_dependencies) a great many of which are hashing strings (Which is when Fnv is the [worst](https://github.com/cbreeden/fxhash#benchmarks), [possible](https://github.com/tkaitchuck/aHash#speed), [choice](http://cglab.ca/~abeinges/blah/hash-rs/).)
I think aHash makes the most sense to mention as an alternative because it is the most credible option (in my obviously biased opinion). It offers [good performance on numbers and strings](https://github.com/tkaitchuck/aHash/blob/master/compare/readme.md#speed), is [of high quality](https://github.com/tkaitchuck/aHash#hash-quality), and [provides dos resistance](https://github.com/tkaitchuck/aHash/wiki/How-aHash-is-resists-DOS-attacks). It is popular (see [stats](https://crates.io/crates/ahash)) and is the default hasher for [hashbrown](https://crates.io/crates/hashbrown) and [dashmap](https://crates.io/crates/dashmap) which are the most popular alternative hashmaps. Finally it does not have any of the [`gotcha` cases](https://github.com/tkaitchuck/aHash#fxhash) that `FxHash` suffers from. (Which is the other popular hashing option when DOS attacks are not a concern)
Signed-off-by: Tom Kaitchuck <tom.kaitchuck@emc.com>
bors [Fri, 13 Nov 2020 11:49:33 +0000 (11:49 +0000)]
Auto merge of #77990 - bugadani:copies, r=lcnr
Eliminate some temporary vectors
This PR changes `get_item_attrs` and `get_item_variances` to return iterator impls instead of vectors. On top of that, this PR replaces some seemingly unnecessary vectors with iterators or SmallVec, and also reserves space where we know (the minimum) number of elements that will be inserted. This change hopes to remove a few heap allocations and unnecessary copies.
bors [Fri, 13 Nov 2020 05:40:37 +0000 (05:40 +0000)]
Auto merge of #78826 - petrochenkov:mrscopes2, r=eddyb
resolve: Collapse `macro_rules` scope chains on the fly
Otherwise they grow too long and you have to endlessly walk through them when resolving macros or imports.
Addresses https://rust-lang.zulipchat.com/#narrow/stream/247081-t-compiler.2Fperformance/topic/Slow.20Builtin.20Derives/near/215750815
J. Ryan Stinnett [Fri, 13 Nov 2020 05:27:36 +0000 (05:27 +0000)]
Clean up outdated `use_once_payload` pretty printer comment
While reading some parts of the pretty printer code, I noticed this old comment
which seemed out of place. The `use_once_payload` this outdated comment mentions
was removed in 2017 in 40f03a1e0d6702add1922f82d716d5b2c23a59f0, so this
completes the work by removing the comment.
Tomasz Miąsko [Thu, 12 Nov 2020 00:00:00 +0000 (00:00 +0000)]
Normalize function type during validation
During inlining, the callee body is normalized and has types revealed,
but some of locals corresponding to the arguments might come from the
caller body which is not. As a result the caller body does not pass
validation without additional normalization.
rustc_parse: Remove optimization for 0-length streams in `collect_tokens`
The optimization conflates empty token streams with unknown token stream, which is at least suspicious, and doesn't affect performance because 0-length token streams are very rare.
Tomasz Miąsko [Wed, 11 Nov 2020 00:00:00 +0000 (00:00 +0000)]
Never inline when `no_sanitize` attributes differ
The inliner looks if a sanitizer is enabled before considering
`no_sanitize` attribute as possible source of incompatibility.
The MIR inlining could happen in a crate with sanitizer disabled, but
code generation in a crate with sanitizer enabled, thus the attribute
would be incorrectly ignored.
To avoid the issue never inline functions with different `no_sanitize`
attributes.
Mara Bos [Thu, 12 Nov 2020 18:46:17 +0000 (19:46 +0100)]
Rollup merge of #78972 - ehuss:update-cargo, r=ehuss
Update cargo
5 commits in d5556aeb8405b1fe696adb6e297ad7a1f2989b62..8662ab427a8d6ad8047811cc4d78dbd20dd07699
2020-11-04 22:20:36 +0000 to 2020-11-12 03:47:53 +0000
- Check if rust-src contains a vendor dir, and patch it in (rust-lang/cargo#8834)
- Improve performance of almost fresh builds (rust-lang/cargo#8837)
- Use u32/64::to/from_le_bytes instead of bit fiddling (rust-lang/cargo#8847)
- Avoid constructing an anyhow::Error when not necessary (rust-lang/cargo#8844)
- Skip extracting .cargo-ok files from packages (rust-lang/cargo#8835)
Mara Bos [Thu, 12 Nov 2020 18:46:14 +0000 (19:46 +0100)]
Rollup merge of #78950 - khyperia:spirv-asm, r=Amanieu
Add asm register information for SPIR-V
As discussed in [zulip](https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/Defining.20asm!.20for.20new.20architecture), we at [rust-gpu](https://github.com/EmbarkStudios/rust-gpu) would like to support `asm!` for our SPIR-V backend. However, we cannot do so purely without frontend support: [this match](https://github.com/rust-lang/rust/blob/d4ea0b3e46a0303d5802b632e88ba1ba84d9d16f/compiler/rustc_target/src/asm/mod.rs#L185) fails and so `asm!` is not supported ([error reported here](https://github.com/rust-lang/rust/blob/d4ea0b3e46a0303d5802b632e88ba1ba84d9d16f/compiler/rustc_ast_lowering/src/expr.rs#L1095)). To resolve this, we need to stub out register information for SPIR-V to support getting the `asm!` content all the way to [`AsmBuilderMethods::codegen_inline_asm`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/traits/trait.AsmBuilderMethods.html#tymethod.codegen_inline_asm), at which point the rust-gpu backend can do all the parsing and codegen that is needed.
This is a pretty weird PR - adding support for a backend that isn't in-tree feels pretty gross to me, but I don't see an easy way around this. ``@Amanieu`` said I should submit it anyway, so, here we are! Let me know if this needs to go through a more formal process (MCP?) and what I should do to help this along.
I based this off the [wasm asm PR](https://github.com/rust-lang/rust/pull/78684), which unfortunately this PR conflicts with that one quite a bit, sorry for any merge conflict pain :(
---
Some open questions:
- What do we call the register class? Some context, SPIR-V is an SSA-based IR, there are "instructions" that create IDs (referred to as `<id>` in the spec), which can be referenced by other instructions. So, `reg` isn't exactly accurate, they're SSA IDs, not re-assignable registers.
- What happens when a SPIR-V register gets to the LLVM backend? Right now it's a `bug!`, but should that be a `sess.fatal()`? I'm not sure if it's even possible to reach that point, maybe there's a check that prevents the `spirv` target from even reaching that codepath.
Mara Bos [Thu, 12 Nov 2020 18:46:11 +0000 (19:46 +0100)]
Rollup merge of #78857 - SkiFire13:bheap-opt, r=KodrAus
Improve BinaryHeap performance
By changing the condition in the loops from `child < end` to `child < end - 1` we're guaranteed that `right = child + 1 < end` and since finding the index of the biggest sibling can be done with an arithmetic operation we can remove a branch from the loop body. The case where there's no right child, i.e. `child == end - 1` is instead handled outside the loop, after it ends; note that if the loops ends early we can use `return` instead of `break` since the check `child == end - 1` will surely fail.
I've also removed a call to `<[T]>::swap` that was hiding a bound check that [wasn't being optimized by LLVM](https://godbolt.org/z/zrhdGM).
A quick benchmarks on my pc shows that the gains are pretty significant:
Mara Bos [Thu, 12 Nov 2020 18:46:09 +0000 (19:46 +0100)]
Rollup merge of #78836 - fanzier:struct-and-slice-destructuring, r=petrochenkov
Implement destructuring assignment for structs and slices
This is the second step towards implementing destructuring assignment (RFC: rust-lang/rfcs#2909, tracking issue: #71126). This PR is the second part of #71156, which was split up to allow for easier review.
Note that the first PR (#78748) is not merged yet, so it is included as the first commit in this one. I thought this would allow the review to start earlier because I have some time this weekend to respond to reviews. If ``@petrochenkov`` prefers to wait until the first PR is merged, I totally understand, of course.
This PR implements destructuring assignment for (tuple) structs and slices. In order to do this, the following *parser change* was necessary: struct expressions are not required to have a base expression, i.e. `Struct { a: 1, .. }` becomes legal (in order to act like a struct pattern).
Unfortunately, this PR slightly regresses the diagnostics implemented in #77283. However, it is only a missing help message in `src/test/ui/issues/issue-77218.rs`. Other instances of this diagnostic are not affected. Since I don't exactly understand how this help message works and how to fix it yet, I was hoping it's OK to regress this temporarily and fix it in a follow-up PR.
Thanks to ``@varkor`` who helped with the implementation, particularly around the struct rest changes.
Joshua Nelson [Sun, 8 Nov 2020 16:45:13 +0000 (11:45 -0500)]
Don't reuse bindings for `ref mut`
Reusing bindings causes errors later in lowering:
```
error[E0596]: cannot borrow `vec` as mutable, as it is not declared as mutable
--> /checkout/src/test/ui/async-await/argument-patterns.rs:12:20
|
LL | async fn b(n: u32, ref mut vec: A) {
| ^^^^^^^^^^^
| |
| cannot borrow as mutable
| help: consider changing this to be mutable: `mut vec`
```
bors [Thu, 12 Nov 2020 15:34:09 +0000 (15:34 +0000)]
Auto merge of #76256 - tgnottingham:issue-74890, r=nikomatsakis
incr-comp: hash and serialize span end line/column
Hash both the length and the end location (line/column) of a span. If we
hash only the length, for example, then two otherwise equal spans with
different end locations will have the same hash. This can cause a
problem during incremental compilation wherein a previous result for a
query that depends on the end location of a span will be incorrectly
reused when the end location of the span it depends on has changed. A
similar analysis applies if some query depends specifically on the
length of the span, but we only hash the end location. So hash both.
I haven't thought about what other problems this root cause could be responsible for. Please let me know if anything springs to mind. I believe the issue has existed since the inception of incremental compilation.
Mark Rousskov [Thu, 12 Nov 2020 14:49:45 +0000 (09:49 -0500)]
Avoid installing external LLVM dylibs
If the LLVM was externally provided, then we don't currently copy artifacts into
the sysroot. This is not necessarily the right choice (in particular, it will
require the LLVM dylib to be in the linker's load path at runtime), but the
common use case for external LLVMs is distribution provided LLVMs, and in that
case they're usually in the standard search path (e.g., /usr/lib) and copying
them here is going to cause problems as we may end up with the wrong files and
isn't what distributions want.
This behavior may be revisited in the future though.
DevJPM [Sat, 7 Nov 2020 22:25:45 +0000 (23:25 +0100)]
fully exploited the dropped support of LLVM 8
This commit grepped for LLVM_VERSION_GE, LLVM_VERSION_LT, get_major_version and
min-llvm-version and statically evaluated every expression possible
(and sensible) assuming that the LLVM version is >=9 now
DevJPM [Sat, 7 Nov 2020 20:25:42 +0000 (21:25 +0100)]
explicitly add llvm-9-dev in dockerfile
apparently llvm-8-tools already had llvm-8-dev as a dependency
which was removed in llvm-9-tools, so we need to explicitly pull
llvm-9-dev to make a build
Guillaume Gomez [Thu, 12 Nov 2020 10:31:51 +0000 (11:31 +0100)]
Rollup merge of #78960 - ethanboxx:const-gen-test-default-error, r=lcnr
Test default values for const parameters.
The last topic on #78433
I originally intended to place these tests in a single file, however, due to them being parser errors that are fatal, they must be in separate files to be detected.
Guillaume Gomez [Thu, 12 Nov 2020 10:31:47 +0000 (11:31 +0100)]
Rollup merge of #78921 - GuillaumeGomez:search-result-title, r=jyn514
Improve the page title switch handling between search and doc
The current behavior often "forgets" to update the page title when discarding/putting back the search results. This isn't optimal which is why I wrote this fix.
Guillaume Gomez [Thu, 12 Nov 2020 10:31:45 +0000 (11:31 +0100)]
Rollup merge of #78916 - lcnr:const-generics-tests, r=varkor
extend const generics test suite
should implement most of #78433, especially all parts of [the hackmd](https://hackmd.io/WnFmN4MjRCqAjGmYfYcu2A?view) which I did not explicitly mention in that issue.
bors [Thu, 12 Nov 2020 10:28:15 +0000 (10:28 +0000)]
Auto merge of #78773 - GuillaumeGomez:theme-picker-shortcut, r=jyn514
Add shortcut for theme picker menu
Follow-up of #78584
Just like you can focus the search input by pressing "S", you can now access the theme picker menu by pressing "T" and navigate through the options only using the keyboard.
Rich Kadel [Sun, 8 Nov 2020 19:06:05 +0000 (11:06 -0800)]
Fix and re-enable two coverage tests on MacOS
Note, in the coverage-reports test, the comment about MacOS was wrong.
The setting is based on config.toml llvm `optimize` setting. There
doesn't appear to be any environment variable I can check, and I
don't think we should add one. Testing the binary itself is a more
reliable way to check anyway.
For the coverage-spanview test, I removed the dependency on sed
altogether, which is much less ugly than trying to work around the
MacOS sed differences.
I tested these changes on Linux, Windows, and Mac.
bors [Thu, 12 Nov 2020 05:52:17 +0000 (05:52 +0000)]
Auto merge of #78965 - jryans:emscripten-threads-libc, r=kennytm
Update thread and futex APIs to work with Emscripten
This updates the thread and futex APIs in `std` to match the APIs exposed by
Emscripten. This allows threads to run on `wasm32-unknown-emscripten` and the
thread parker to compile without errors related to the missing `futex` module.
To make use of this, Rust code must be compiled with `-C target-feature=atomics`
and Emscripten must link with `-pthread`.
I have confirmed this works well locally when building multithreaded crates.
Attempting to enable `std` thread tests currently fails for seemingly obscure
reasons and Emscripten is currently disabled in CI, so further work is needed to
have proper test coverage here.
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