Use generator resume arguments in the async/await lowering #69033

jonas-schievink · 2020-02-10T17:17:28Z

This removes the TLS requirement from async/await and enables it in #![no_std] crates.

I'm not confident the HIR lowering is completely correct, there seem to be quite a few undocumented invariants in there. The async-std and tokio test suites are passing with these changes though.

rust-highfive · 2020-02-10T17:17:32Z

r? @davidtwco

(rust_highfive has picked a reviewer for you, use r? to override)

src/librustc_ast_lowering/expr.rs

Centril · 2020-02-10T20:04:00Z

src/librustc_ast_lowering/expr.rs

+        let task_context_id = self.resolver.next_node_id();
+        let task_context_hid = self.lower_node_id(task_context_id);
+        let ast_decl = FnDecl {
+            inputs: vec![Param {
+                attrs: AttrVec::new(),
+                ty: AstP(Ty {
+                    id: self.resolver.next_node_id(),
+                    kind: TyKind::Infer,
+                    span: DUMMY_SP,
+                }),
+                pat: AstP(Pat {
+                    id: task_context_id,
+                    kind: PatKind::Ident(
+                        BindingMode::ByValue(Mutability::Mut),
+                        Ident::with_dummy_span(sym::_task_context),
+                        None,
+                    ),
+                    span: DUMMY_SP,
+                }),
+                id: self.resolver.next_node_id(),
+                span: DUMMY_SP,
+                is_placeholder: false,
+            }],
+            output,
+        };


I don't think we should be creating syntax::ast IR inside lowering just to immediately convert it to HIR. Instead, the HIR representation should be created directly. (cc @eddyb)

That makes sense to me, but there seems to be no existing code that directly creates an hir::FnDecl, and lower_fn_decl does quite a lot of work that I don't really want to hand-roll.

It's not that much code tbh which I think can be mostly shared by some refactorings of lower_fn_decl into the main parts (inputs, output, implicit_self, packaging those aforementioned up) as separate methods.

I've pushed a commit that should address this

src/libcore/future/mod.rs

Centril · 2020-02-10T20:08:44Z

src/test/ui/async-await/no-std.rs

+    f.await;
+}
+
+fn main() {}


Could we test more like a whole program with more interactions?

Please add more run-pass with:

spawn onto the main thread with a basic waker vtable

a spinlock holds that task

There are already a lot of tests for async/await, most just don't turn on the #![no_std] flag. Since the underlying implementation is the same there is not really a difference though.

(I'm not entirely sure what the spinlock test would accomplish here though, you can store tasks however you want as long as you can get a Pin<&mut Self> to poll the future)

There are already a lot of tests for async/await, most just don't turn on the #![no_std] flag.

If we have a build matrix that enables no_std flag for async/await tests, it is ok to not add tests.(iirc we don't have) I assume compiler harness doesn't do that unless you explicitly ask for it. So when it is passing for std doesn't mean that it will pass by all cases of no_std.

(I'm not entirely sure what the spinlock test would accomplish here though,

To demonstrate also it is working in no_std env without any extra dependency brought in.

davidtwco · 2020-02-11T11:17:37Z

r? @tmandry

nikomatsakis · 2020-02-14T18:39:18Z

I'm excited to see this, thanks @jonas-schievink

CryZe · 2020-02-19T19:13:15Z

What's the status of this? Is this blocked on #69039 or could this be merged before that is resolved?

jonas-schievink · 2020-02-19T19:32:30Z

@CryZe I've started to write a test that should provide an answer to that, but I also plan to look into #69039 regardless. I hope to find some time to finish this off in the next couple of weeks.

src/libcore/future/mod.rs

src/librustc_span/symbol.rs

src/libcore/future/mod.rs

tmandry

Sorry for the latency on my end.

src/libcore/future/mod.rs

Don't store locals in generators that are immediately overwritten with the resume argument This fixes #69672 and makes #69033 pass the async fn size tests again (in other words, there will be no size regression of async fn if both this and #69033 land). ~~This is a small botch and I'd rather have a more precise analysis, but that seems much harder to pull off, so this special-cases `Yield` terminators that store the resume argument into a simple local (ie. without any field projections) and explicitly marks that local as "not live" in the suspend point of that yield. We know that this local does not need to be stored in the generator for this suspend point because the next resume would immediately overwrite it with the passed-in resume argument anyways. The local might still end up in the state if it is used across another yield.~~ (this now properly updates the dataflow framework to handle this case)

…, r=tmandry Use generator resume arguments in the async/await lowering This removes the TLS requirement from async/await and enables it in `#![no_std]` crates. Closes rust-lang#56974 I'm not confident the HIR lowering is completely correct, there seem to be quite a few undocumented invariants in there. The `async-std` and tokio test suites are passing with these changes though.

@ghost

Rollup of 16 pull requests Successful merges: - rust-lang#65097 (Make std::sync::Arc compatible with ThreadSanitizer) - rust-lang#69033 (Use generator resume arguments in the async/await lowering) - rust-lang#69997 (add `Option::{zip,zip_with}` methods under "option_zip" gate) - rust-lang#70038 (Remove the call that makes miri fail) - rust-lang#70058 (can_begin_literal_maybe_minus: `true` on `"-"? lit` NTs.) - rust-lang#70111 (BTreeMap: remove shared root) - rust-lang#70139 (add delay_span_bug to TransmuteSizeDiff, just to be sure) - rust-lang#70165 (Remove the erase regions MIR transform) - rust-lang#70166 (Derive PartialEq, Eq and Hash for RangeInclusive) - rust-lang#70176 (Add tests for rust-lang#58319 and rust-lang#65131) - rust-lang#70177 (Fix oudated comment for NamedRegionMap) - rust-lang#70184 (expand_include: set `.directory` to dir of included file.) - rust-lang#70187 (more clippy fixes) - rust-lang#70188 (Clean up E0439 explanation) - rust-lang#70189 (Abi::is_signed: assert that we are a Scalar) - rust-lang#70194 (#[must_use] on split_off()) Failed merges: r? @ghost

benma · 2020-03-22T20:55:29Z

Tested in on nightly, works great. Awesome work!

A bit new to Rust release scheduling; will this be in stable with the next release, or do we need to wait until 1.44 is stable, which is not until June?

jonas-schievink · 2020-03-22T21:02:17Z

This will land in 1.44 (and will hit beta in 1.43)

benma · 2020-03-22T21:12:40Z

Thx. Any chance to put it into the next stable release? After all, it's an implementation detail, not a language change.

jonas-schievink · 2020-03-22T21:17:13Z

No, we only backport bug fixes

This is to be able to use async/await syntax, which was merged a few days ago into nightly for no_std: rust-lang/rust#69033. This feature will be in beta in April and stable in June, at which point we can start to use those channels again. rust-toolchain file is added as a sanity check or for devs/users not using Docker.

kpp · 2020-03-27T23:39:24Z

@jonas-schievink Hi. I got a 300% performance degradation on 1.44.0-nightly 2fbb075 2020-03-26 compared to stable 1.42 b8cedc0 2020-03-09 while benching futures.

Criterion output

future::ready/futures   time:   [1.5667 ns 1.5712 ns 1.5762 ns]                                   
                        change: [+223.24% +232.94% +242.84%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 6 outliers among 100 measurements (6.00%)
  1 (1.00%) low mild
  5 (5.00%) high mild
future::ready/async_combinators                                                                             
                        time:   [1.5699 ns 1.5743 ns 1.5793 ns]
                        change: [+279.32% +282.34% +285.20%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
  3 (3.00%) low mild
  2 (2.00%) high mild
  3 (3.00%) high severe

future::poll_fn/futures time:   [260.26 ps 260.82 ps 261.40 ps]                                    
                        change: [-3.2265% -2.6712% -2.0788%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 9 outliers among 100 measurements (9.00%)
  5 (5.00%) high mild
  4 (4.00%) high severe
Benchmarking future::poll_fn/async_combinators: Collecting 100 samples in estimated 5.0000 s (19B iterations                                                                                                            future::poll_fn/async_combinators                        
                        time:   [260.18 ps 260.91 ps 261.77 ps]
                        change: [-1.3517% -0.6763% -0.0422%] (p = 0.05 < 0.05)
                        Change within noise threshold.
Found 10 outliers among 100 measurements (10.00%)
  3 (3.00%) low mild
  4 (4.00%) high mild
  3 (3.00%) high severe

future::map/futures     time:   [2.1487 ns 2.1544 ns 2.1601 ns]                                 
                        change: [+296.27% +298.58% +300.54%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
  2 (2.00%) low severe
  1 (1.00%) low mild
  4 (4.00%) high mild
  1 (1.00%) high severe
future::map/async_combinators                                                                             
                        time:   [3.1330 ns 3.1393 ns 3.1458 ns]
                        change: [+233.70% +236.33% +238.68%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 5 outliers among 100 measurements (5.00%)
  2 (2.00%) low mild
  3 (3.00%) high mild

     Running target/release/deps/stream-ff2c5e87168d8d4c
stream::iter/futures    time:   [3.1216 ns 3.1275 ns 3.1341 ns]                                  
                        change: [+290.24% +293.62% +297.39%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
  1 (1.00%) low mild
  6 (6.00%) high mild
  4 (4.00%) high severe
stream::iter/async_combinators                                                                             
                        time:   [3.1331 ns 3.1423 ns 3.1532 ns]
                        change: [+280.94% +283.80% +286.95%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 7 outliers among 100 measurements (7.00%)
  1 (1.00%) low mild
  3 (3.00%) high mild
  3 (3.00%) high severe

stream::next/futures    time:   [3.3549 ns 3.4282 ns 3.5139 ns]                                  
                        change: [+319.16% +327.38% +336.10%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 2 outliers among 100 measurements (2.00%)
  2 (2.00%) high severe
stream::next/async_combinators                                                                             
                        time:   [3.1806 ns 3.2330 ns 3.2933 ns]
                        change: [+288.17% +292.97% +297.98%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
  3 (3.00%) high mild
  10 (10.00%) high severe

stream::collect/futures time:   [6.3038 ns 6.3446 ns 6.3928 ns]                                     
                        change: [+298.95% +301.74% +305.36%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 17 outliers among 100 measurements (17.00%)
  4 (4.00%) low mild
  9 (9.00%) high mild
  4 (4.00%) high severe
Benchmarking stream::collect/async_combinators: Collecting 100 samples in estimated 5.0000 s (456M iteration                                                                                                            stream::collect/async_combinators                        
                        time:   [11.661 ns 12.051 ns 12.435 ns]
                        change: [+320.32% +329.63% +340.16%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 4 outliers among 100 measurements (4.00%)
  3 (3.00%) high mild
  1 (1.00%) high severe

stream::map/futures     time:   [6.8157 ns 6.9007 ns 6.9814 ns]                                 
                        change: [+305.37% +309.91% +314.44%] (p = 0.00 < 0.05)
                        Performance has regressed.
stream::map/async_combinators                                                                             
                        time:   [7.0993 ns 7.2319 ns 7.3715 ns]
                        change: [+339.77% +348.71% +358.18%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 5 outliers among 100 measurements (5.00%)
  3 (3.00%) high mild
  2 (2.00%) high severe

stream::fold/futures    time:   [4.3133 ns 4.3516 ns 4.4018 ns]                                  
                        change: [+277.61% +283.58% +291.19%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 3 outliers among 100 measurements (3.00%)
  3 (3.00%) high mild
stream::fold/async_combinators                                                                             
                        time:   [9.3900 ns 9.4145 ns 9.4431 ns]
                        change: [+259.06% +261.65% +264.17%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
  7 (7.00%) high mild
  6 (6.00%) high severe

I know my benchmarks are not perfect. Still 300% is a lot.

Would you please take a look?

===

Update: my benchmarks turned out to bench nothing.

goffrie · 2020-03-28T00:16:01Z

I was able to reproduce the regression, but it's not from this PR: 5f13820 and 1057dc9 are both equally slow.

goffrie · 2020-03-28T01:10:54Z

Bisecting shows that 57e1da5 introduced the regression.

Mark-Simulacrum · 2020-03-28T01:11:07Z

Please file new issue(s) for problems arising as a result of PRs, otherwise it's highly likely to get lost.

Pkgsrc changes: * Remove a couple diffs which are now integrated upstream. * Adjust cargo checksums after upstream upgrades. * Belatedly bump the curl dependency * Unset DESTDIR during the build phase, to work around a mysterious build bug deep in the bowels of llvm. * Bump nearly all bootstraps to 1.43.1. Upstream changes: Version 1.44.0 (2020-06-04) ========================== Language -------- - [You can now use `async/.await` with `#[no_std]` enabled.][69033] - [Added the `unused_braces` lint.][70081] **Syntax-only changes** - [Expansion-driven outline module parsing][69838] ```rust #[cfg(FALSE)] mod foo { mod bar { mod baz; // `foo/bar/baz.rs` doesn't exist, but no error! } } ``` These are still rejected semantically, so you will likely receive an error but these changes can be seen and parsed by macros and conditional compilation. Compiler -------- - [Rustc now respects the `-C codegen-units` flag in incremental mode.][70156] Additionally when in incremental mode rustc defaults to 256 codegen units. - [Refactored `catch_unwind`, to have zero-cost unless unwinding is enabled and a panic is thrown.][67502] - [Added tier 3\* support for the `aarch64-unknown-none` and `aarch64-unknown-none-softfloat` targets.][68334] - [Added tier 3 support for `arm64-apple-tvos` and `x86_64-apple-tvos` targets.][68191] Libraries --------- - [Special cased `vec![]` to map directly to `Vec::new()`.][70632] This allows `vec![]` to be able to be used in `const` contexts. - [`convert::Infallible` now implements `Hash`.][70281] - [`OsString` now implements `DerefMut` and `IndexMut` returning a `&mut OsStr`.][70048] - [Unicode 13 is now supported.][69929] - [`String` now implements `From<&mut str>`.][69661] - [`IoSlice` now implements `Copy`.][69403] - [`Vec<T>` now implements `From<[T; N]>`.][68692] Where `N` is less than 32. - [`proc_macro::LexError` now implements `fmt::Display` and `Error`.][68899] - [`from_le_bytes`, `to_le_bytes`, `from_be_bytes`, `to_be_bytes`, `from_ne_bytes`, and `to_ne_bytes` methods are now `const` for all integer types.][69373] Stabilized APIs --------------- - [`PathBuf::with_capacity`] - [`PathBuf::capacity`] - [`PathBuf::clear`] - [`PathBuf::reserve`] - [`PathBuf::reserve_exact`] - [`PathBuf::shrink_to_fit`] - [`f32::to_int_unchecked`] - [`f64::to_int_unchecked`] - [`Layout::align_to`] - [`Layout::pad_to_align`] - [`Layout::array`] - [`Layout::extend`] Cargo ----- - [Added the `cargo tree` command which will print a tree graph of your dependencies.][cargo/8062] E.g. ``` mdbook v0.3.2 (/Users/src/rust/mdbook) +-- ammonia v3.0.0 | +-- html5ever v0.24.0 | | +-- log v0.4.8 | | | +-- cfg-if v0.1.9 | | +-- mac v0.1.1 | | +-- markup5ever v0.9.0 | | +-- log v0.4.8 (*) | | +-- phf v0.7.24 | | | +-- phf_shared v0.7.24 | | | +-- siphasher v0.2.3 | | | +-- unicase v1.4.2 | | | [build-dependencies] | | | +-- version_check v0.1.5 ... ``` You can also display dependencies on multiple versions of the same crate with `cargo tree -d` (short for `cargo tree --duplicates`). Misc ---- - [Rustdoc now allows you to specify `--crate-version` to have rustdoc include the version in the sidebar.][69494] Compatibility Notes ------------------- - [Rustc now correctly generates static libraries on Windows GNU targets with the `.a` extension, rather than the previous `.lib`.][70937] - [Removed the `-C no_integrated_as` flag from rustc.][70345] - [The `file_name` property in JSON output of macro errors now points the actual source file rather than the previous format of `<NAME macros>`.][70969] **Note:** this may not point a file that actually exists on the user's system. - [The minimum required external LLVM version has been bumped to LLVM 8.][71147] - [`mem::{zeroed, uninitialised}` will now panic when used with types that do not allow zero initialization such as `NonZeroU8`.][66059] This was previously a warning. - [In 1.45.0 (the next release) converting a `f64` to `u32` using the `as` operator has been defined as a saturating operation.][71269] This was previously undefined behaviour, you can use the `{f64, f32}::to_int_unchecked` methods to continue using the current behaviour which may desirable in rare performance sensitive situations. Internal Only ------------- These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. - [dep_graph Avoid allocating a set on when the number reads are small.][69778] - [Replace big JS dict with JSON parsing.][71250] [69373]: rust-lang/rust#69373 [66059]: rust-lang/rust#66059 [68191]: rust-lang/rust#68191 [68899]: rust-lang/rust#68899 [71147]: rust-lang/rust#71147 [71250]: rust-lang/rust#71250 [70937]: rust-lang/rust#70937 [70969]: rust-lang/rust#70969 [70632]: rust-lang/rust#70632 [70281]: rust-lang/rust#70281 [70345]: rust-lang/rust#70345 [70048]: rust-lang/rust#70048 [70081]: rust-lang/rust#70081 [70156]: rust-lang/rust#70156 [71269]: rust-lang/rust#71269 [69838]: rust-lang/rust#69838 [69929]: rust-lang/rust#69929 [69661]: rust-lang/rust#69661 [69778]: rust-lang/rust#69778 [69494]: rust-lang/rust#69494 [69403]: rust-lang/rust#69403 [69033]: rust-lang/rust#69033 [68692]: rust-lang/rust#68692 [68334]: rust-lang/rust#68334 [67502]: rust-lang/rust#67502 [cargo/8062]: rust-lang/cargo#8062 [`PathBuf::with_capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.with_capacity [`PathBuf::capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.capacity [`PathBuf::clear`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.clear [`PathBuf::reserve`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve [`PathBuf::reserve_exact`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve_exact [`PathBuf::shrink_to_fit`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.shrink_to_fit [`f32::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_int_unchecked [`f64::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_int_unchecked [`Layout::align_to`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.align_to [`Layout::pad_to_align`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.pad_to_align [`Layout::array`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.array [`Layout::extend`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.extend

Version 1.44.0 (2020-06-04) ========================== Language -------- - [You can now use `async/.await` with `#[no_std]` enabled.][69033] - [Added the `unused_braces` lint.][70081] **Syntax-only changes** - [Expansion-driven outline module parsing][69838] ```rust #[cfg(FALSE)] mod foo { mod bar { mod baz; // `foo/bar/baz.rs` doesn't exist, but no error! } } ``` These are still rejected semantically, so you will likely receive an error but these changes can be seen and parsed by macros and conditional compilation. Compiler -------- - [Rustc now respects the `-C codegen-units` flag in incremental mode.][70156] Additionally when in incremental mode rustc defaults to 256 codegen units. - [Refactored `catch_unwind` to have zero-cost, unless unwinding is enabled and a panic is thrown.][67502] - [Added tier 3\* support for the `aarch64-unknown-none` and `aarch64-unknown-none-softfloat` targets.][68334] - [Added tier 3 support for `arm64-apple-tvos` and `x86_64-apple-tvos` targets.][68191] Libraries --------- - [Special cased `vec![]` to map directly to `Vec::new()`.][70632] This allows `vec![]` to be able to be used in `const` contexts. - [`convert::Infallible` now implements `Hash`.][70281] - [`OsString` now implements `DerefMut` and `IndexMut` returning a `&mut OsStr`.][70048] - [Unicode 13 is now supported.][69929] - [`String` now implements `From<&mut str>`.][69661] - [`IoSlice` now implements `Copy`.][69403] - [`Vec<T>` now implements `From<[T; N]>`.][68692] Where `N` is at most 32. - [`proc_macro::LexError` now implements `fmt::Display` and `Error`.][68899] - [`from_le_bytes`, `to_le_bytes`, `from_be_bytes`, `to_be_bytes`, `from_ne_bytes`, and `to_ne_bytes` methods are now `const` for all integer types.][69373] Stabilized APIs --------------- - [`PathBuf::with_capacity`] - [`PathBuf::capacity`] - [`PathBuf::clear`] - [`PathBuf::reserve`] - [`PathBuf::reserve_exact`] - [`PathBuf::shrink_to_fit`] - [`f32::to_int_unchecked`] - [`f64::to_int_unchecked`] - [`Layout::align_to`] - [`Layout::pad_to_align`] - [`Layout::array`] - [`Layout::extend`] Cargo ----- - [Added the `cargo tree` command which will print a tree graph of your dependencies.][cargo/8062] E.g. ``` mdbook v0.3.2 (/Users/src/rust/mdbook) ├── ammonia v3.0.0 │ ├── html5ever v0.24.0 │ │ ├── log v0.4.8 │ │ │ └── cfg-if v0.1.9 │ │ ├── mac v0.1.1 │ │ └── markup5ever v0.9.0 │ │ ├── log v0.4.8 (*) │ │ ├── phf v0.7.24 │ │ │ └── phf_shared v0.7.24 │ │ │ ├── siphasher v0.2.3 │ │ │ └── unicase v1.4.2 │ │ │ [build-dependencies] │ │ │ └── version_check v0.1.5 ... ``` You can also display dependencies on multiple versions of the same crate with `cargo tree -d` (short for `cargo tree --duplicates`). Misc ---- - [Rustdoc now allows you to specify `--crate-version` to have rustdoc include the version in the sidebar.][69494] Compatibility Notes ------------------- - [Rustc now correctly generates static libraries on Windows GNU targets with the `.a` extension, rather than the previous `.lib`.][70937] - [Removed the `-C no_integrated_as` flag from rustc.][70345] - [The `file_name` property in JSON output of macro errors now points the actual source file rather than the previous format of `<NAME macros>`.][70969] **Note:** this may not point to a file that actually exists on the user's system. - [The minimum required external LLVM version has been bumped to LLVM 8.][71147] - [`mem::{zeroed, uninitialised}` will now panic when used with types that do not allow zero initialization such as `NonZeroU8`.][66059] This was previously a warning. - [In 1.45.0 (the next release) converting a `f64` to `u32` using the `as` operator has been defined as a saturating operation.][71269] This was previously undefined behaviour, but you can use the `{f64, f32}::to_int_unchecked` methods to continue using the current behaviour, which may be desirable in rare performance sensitive situations. Internal Only ------------- These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. - [dep_graph Avoid allocating a set on when the number reads are small.][69778] - [Replace big JS dict with JSON parsing.][71250] [69373]: rust-lang/rust#69373 [66059]: rust-lang/rust#66059 [68191]: rust-lang/rust#68191 [68899]: rust-lang/rust#68899 [71147]: rust-lang/rust#71147 [71250]: rust-lang/rust#71250 [70937]: rust-lang/rust#70937 [70969]: rust-lang/rust#70969 [70632]: rust-lang/rust#70632 [70281]: rust-lang/rust#70281 [70345]: rust-lang/rust#70345 [70048]: rust-lang/rust#70048 [70081]: rust-lang/rust#70081 [70156]: rust-lang/rust#70156 [71269]: rust-lang/rust#71269 [69838]: rust-lang/rust#69838 [69929]: rust-lang/rust#69929 [69661]: rust-lang/rust#69661 [69778]: rust-lang/rust#69778 [69494]: rust-lang/rust#69494 [69403]: rust-lang/rust#69403 [69033]: rust-lang/rust#69033 [68692]: rust-lang/rust#68692 [68334]: rust-lang/rust#68334 [67502]: rust-lang/rust#67502 [cargo/8062]: rust-lang/cargo#8062 [`PathBuf::with_capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.with_capacity [`PathBuf::capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.capacity [`PathBuf::clear`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.clear [`PathBuf::reserve`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve [`PathBuf::reserve_exact`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve_exact [`PathBuf::shrink_to_fit`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.shrink_to_fit [`f32::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_int_unchecked [`f64::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_int_unchecked [`Layout::align_to`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.align_to [`Layout::pad_to_align`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.pad_to_align [`Layout::array`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.array [`Layout::extend`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.extend

Pkgsrc changes: * Remove the clutter caused by the cross-compile setup from Makefile (Now consigned to my own private cross.mk file.) * Remove a couple of patches which are now integrated upstream. * Minor adjustments to a couple of other patches. * Adjust cargo checksums after upstream upgrades. * Belatedly bump the curl dependency * If doing a "dist" build, unset DESTDIR during the build phase, to work around a mysterious build bug deep in the bowels of llvm, causing llvm tools to be installed to a directory unexpecetd by the rest of the rust build, ref. rust-lang/rust#73132 A "dist" build is not expected to be followed by an "install". * Bump nearly all bootstraps to 1.43.1; NetBSD earmv7hf bootstrap bumped to 1.44.0, as that one now finally builds and works. Upstream changes: Version 1.44.0 (2020-06-04) ========================== Language -------- - [You can now use `async/.await` with `#[no_std]` enabled.][69033] - [Added the `unused_braces` lint.][70081] **Syntax-only changes** - [Expansion-driven outline module parsing][69838] ```rust #[cfg(FALSE)] mod foo { mod bar { mod baz; // `foo/bar/baz.rs` doesn't exist, but no error! } } ``` These are still rejected semantically, so you will likely receive an error but these changes can be seen and parsed by macros and conditional compilation. Compiler -------- - [Rustc now respects the `-C codegen-units` flag in incremental mode.][70156] Additionally when in incremental mode rustc defaults to 256 codegen units. - [Refactored `catch_unwind`, to have zero-cost unless unwinding is enabled and a panic is thrown.][67502] - [Added tier 3\* support for the `aarch64-unknown-none` and `aarch64-unknown-none-softfloat` targets.][68334] - [Added tier 3 support for `arm64-apple-tvos` and `x86_64-apple-tvos` targets.][68191] Libraries --------- - [Special cased `vec![]` to map directly to `Vec::new()`.][70632] This allows `vec![]` to be able to be used in `const` contexts. - [`convert::Infallible` now implements `Hash`.][70281] - [`OsString` now implements `DerefMut` and `IndexMut` returning a `&mut OsStr`.][70048] - [Unicode 13 is now supported.][69929] - [`String` now implements `From<&mut str>`.][69661] - [`IoSlice` now implements `Copy`.][69403] - [`Vec<T>` now implements `From<[T; N]>`.][68692] Where `N` is less than 32. - [`proc_macro::LexError` now implements `fmt::Display` and `Error`.][68899] - [`from_le_bytes`, `to_le_bytes`, `from_be_bytes`, `to_be_bytes`, `from_ne_bytes`, and `to_ne_bytes` methods are now `const` for all integer types.][69373] Stabilized APIs --------------- - [`PathBuf::with_capacity`] - [`PathBuf::capacity`] - [`PathBuf::clear`] - [`PathBuf::reserve`] - [`PathBuf::reserve_exact`] - [`PathBuf::shrink_to_fit`] - [`f32::to_int_unchecked`] - [`f64::to_int_unchecked`] - [`Layout::align_to`] - [`Layout::pad_to_align`] - [`Layout::array`] - [`Layout::extend`] Cargo ----- - [Added the `cargo tree` command which will print a tree graph of your dependencies.][cargo/8062] E.g. ``` mdbook v0.3.2 (/Users/src/rust/mdbook) +-- ammonia v3.0.0 | +-- html5ever v0.24.0 | | +-- log v0.4.8 | | | +-- cfg-if v0.1.9 | | +-- mac v0.1.1 | | +-- markup5ever v0.9.0 | | +-- log v0.4.8 (*) | | +-- phf v0.7.24 | | | +-- phf_shared v0.7.24 | | | +-- siphasher v0.2.3 | | | +-- unicase v1.4.2 | | | [build-dependencies] | | | +-- version_check v0.1.5 ... ``` You can also display dependencies on multiple versions of the same crate with `cargo tree -d` (short for `cargo tree --duplicates`). Misc ---- - [Rustdoc now allows you to specify `--crate-version` to have rustdoc include the version in the sidebar.][69494] Compatibility Notes ------------------- - [Rustc now correctly generates static libraries on Windows GNU targets with the `.a` extension, rather than the previous `.lib`.][70937] - [Removed the `-C no_integrated_as` flag from rustc.][70345] - [The `file_name` property in JSON output of macro errors now points the actual source file rather than the previous format of `<NAME macros>`.][70969] **Note:** this may not point a file that actually exists on the user's system. - [The minimum required external LLVM version has been bumped to LLVM 8.][71147] - [`mem::{zeroed, uninitialised}` will now panic when used with types that do not allow zero initialization such as `NonZeroU8`.][66059] This was previously a warning. - [In 1.45.0 (the next release) converting a `f64` to `u32` using the `as` operator has been defined as a saturating operation.][71269] This was previously undefined behaviour, you can use the `{f64, f32}::to_int_unchecked` methods to continue using the current behaviour which may desirable in rare performance sensitive situations. Internal Only ------------- These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. - [dep_graph Avoid allocating a set on when the number reads are small.][69778] - [Replace big JS dict with JSON parsing.][71250] [69373]: rust-lang/rust#69373 [66059]: rust-lang/rust#66059 [68191]: rust-lang/rust#68191 [68899]: rust-lang/rust#68899 [71147]: rust-lang/rust#71147 [71250]: rust-lang/rust#71250 [70937]: rust-lang/rust#70937 [70969]: rust-lang/rust#70969 [70632]: rust-lang/rust#70632 [70281]: rust-lang/rust#70281 [70345]: rust-lang/rust#70345 [70048]: rust-lang/rust#70048 [70081]: rust-lang/rust#70081 [70156]: rust-lang/rust#70156 [71269]: rust-lang/rust#71269 [69838]: rust-lang/rust#69838 [69929]: rust-lang/rust#69929 [69661]: rust-lang/rust#69661 [69778]: rust-lang/rust#69778 [69494]: rust-lang/rust#69494 [69403]: rust-lang/rust#69403 [69033]: rust-lang/rust#69033 [68692]: rust-lang/rust#68692 [68334]: rust-lang/rust#68334 [67502]: rust-lang/rust#67502 [cargo/8062]: rust-lang/cargo#8062 [`PathBuf::with_capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.with_capacity [`PathBuf::capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.capacity [`PathBuf::clear`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.clear [`PathBuf::reserve`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve [`PathBuf::reserve_exact`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve_exact [`PathBuf::shrink_to_fit`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.shrink_to_fit [`f32::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_int_unchecked [`f64::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_int_unchecked [`Layout::align_to`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.align_to [`Layout::pad_to_align`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.pad_to_align [`Layout::array`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.array [`Layout::extend`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.extend

rust-highfive assigned davidtwco Feb 10, 2020

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Cannot define async fn with no_std #56974

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rust-highfive assigned tmandry and unassigned davidtwco Feb 11, 2020

CryZe mentioned this pull request Feb 18, 2020

Rewrite the Debug Menu to use async await CryZe/WindWakerDebugMenu#11

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roblabla mentioned this pull request Feb 20, 2020

add support for latest nightly with generator resume arguments sunriseos/core-futures-tls#2

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jonas-schievink mentioned this pull request Mar 3, 2020

x = yield; makes generators larger than they need to be #69672

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jonas-schievink mentioned this pull request Mar 4, 2020

Don't store locals in generators that are immediately overwritten with the resume argument #69716

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taiki-e mentioned this pull request Mar 8, 2020

Update for generator resume arguments taiki-e/futures-async-stream#34

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JohnCSimon added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 9, 2020

Centril mentioned this pull request Mar 21, 2020

Rollup of 17 pull requests #70203

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Centril mentioned this pull request Mar 21, 2020

Rollup of 16 pull requests #70205

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bors merged commit ef7c8a1 into rust-lang:master Mar 21, 2020

jonas-schievink deleted the resume-with-context branch March 21, 2020 09:37

jonas-schievink added the relnotes Marks issues that should be documented in the release notes of the next release. label Mar 21, 2020

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benma mentioned this pull request Mar 25, 2020

rust: use nightly-2020-03-25 BitBoxSwiss/bitbox02-firmware#427

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Woyten mentioned this pull request Mar 27, 2020

WIP: Decommission async-support tock/libtock-rs#170

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goffrie mentioned this pull request Mar 28, 2020

Async performance regression #70488

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Centril mentioned this pull request Mar 31, 2020

internal compiler error: no type for local variable #70594

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benma mentioned this pull request Mar 31, 2020

no_std mcginty/snow#62

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o0Ignition0o mentioned this pull request Apr 4, 2020

adding support for no_std executor bastion-rs/agnostik#7

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yoshuawuyts mentioned this pull request Jul 31, 2020

LLVM error: "Instruction does not dominate all uses!" on Windows #72470

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Why asynchronous Rust doesn't work eeeeeta/blog-comments#10

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Use generator resume arguments in the async/await lowering #69033

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