Turn `#[global_allocator]` into a regular attribute macro #62735

petrochenkov · 2019-07-16T22:52:03Z

It was a 99% macro with exception of some diagnostic details.

As a result of the change, #[global_allocator] now works in nested modules and even in nameless blocks.

Fixes #44113
Fixes #58072

rust-highfive · 2019-07-16T22:52:13Z

r? @nikomatsakis

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petrochenkov · 2019-07-19T00:07:38Z

r? @eddyb

eddyb · 2019-07-19T06:48:36Z

r=me but I'd also check with @alexcrichton

petrochenkov · 2019-07-19T09:44:37Z

r? @alexcrichton

alexcrichton

Thanks @petrochenkov!

Definitely agree this should have been a macro from the start!

This makes me wonder if we can make #[proc_macro] and friends macros...

src/libsyntax_ext/lib.rs

src/test/ui/feature-gate/issue-43106-gating-of-test.stderr

src/tools/tidy/src/features.rs

petrochenkov · 2019-07-19T19:31:11Z

This makes me wonder if we can make #[proc_macro] and friends macros...

Right now the proc macro harness generated for --crate-type proc-macro crates looks like this:

#[doc(hidden)]
pub mod decls {
    extern crate proc_macro;
    #[rustc_proc_macro_decls]
    pub static _DECLS: &[proc_macro::bridge::client::ProcMacro] =
        &[proc_macro::bridge::client::ProcMacro::custom_derive("MyDerive",
                                                               &[],
                                                               crate::my_derive),
          proc_macro::bridge::client::ProcMacro::attr("my_attr",
                                                      crate::my_attr),
          proc_macro::bridge::client::ProcMacro::bang("my_macro",
                                                      crate::my_macro)];
}

So, it cannot be generated by individual #[proc_macro*] attributes without a rework of the proc macro crate ABI.

alexcrichton · 2019-07-19T20:16:25Z

Ok r=me if you're confident #[test] won't cause much breakage, it's easy to back out anyway. If you'd like to change it to wire up to a lint r=me also on that.

petrochenkov · 2019-07-20T00:31:10Z

@bors r=alexcrichton

bors · 2019-07-20T00:31:11Z

📌 Commit d2726fbbbe9c0ce97f4c3458185b0e7846c1f0bb has been approved by alexcrichton

bors · 2019-07-20T00:54:35Z

☔ The latest upstream changes (presumably #62705) made this pull request unmergeable. Please resolve the merge conflicts.

petrochenkov · 2019-07-24T09:47:43Z

@bors r=alexcrichton

bors · 2019-07-24T09:47:45Z

📌 Commit a0c2c64 has been approved by alexcrichton

Turn `#[global_allocator]` into a regular attribute macro It was a 99% macro with exception of some diagnostic details. As a result of the change, `#[global_allocator]` now works in nested modules and even in nameless blocks. Fixes rust-lang#44113 Fixes rust-lang#58072

@ghost

Rollup of 10 pull requests Successful merges: - rust-lang#60938 (rustdoc: make #[doc(include)] relative to the containing file) - rust-lang#61890 (Fix some sanity checks) - rust-lang#62261 (Take substs into account in `conservative_is_privately_uninhabited`) - rust-lang#62528 (Add joining slices of slices with a slice separator, not just a single item) - rust-lang#62735 (Turn `#[global_allocator]` into a regular attribute macro) - rust-lang#62801 (Remove support for -Zlower-128bit-ops) - rust-lang#62808 (Revert "Disable stack probing for gnux32.") - rust-lang#62819 (Display name of crate requiring rustc_private in error messages.) - rust-lang#62904 (Disable d32 on armv6 hf targets) - rust-lang#62907 (Initialize the MSP430 AsmParser) Failed merges: r? @ghost

Turn `#[global_allocator]` into a regular attribute macro It was a 99% macro with exception of some diagnostic details. As a result of the change, `#[global_allocator]` now works in nested modules and even in nameless blocks. Fixes rust-lang#44113 Fixes rust-lang#58072

@ghost

Rollup of 13 pull requests Successful merges: - rust-lang#60938 (rustdoc: make #[doc(include)] relative to the containing file) - rust-lang#61890 (Fix some sanity checks) - rust-lang#62084 (allow clippy::unreadable_literal in unicode tables) - rust-lang#62261 (Take substs into account in `conservative_is_privately_uninhabited`) - rust-lang#62528 (Add joining slices of slices with a slice separator, not just a single item) - rust-lang#62735 (Turn `#[global_allocator]` into a regular attribute macro) - rust-lang#62801 (Remove support for -Zlower-128bit-ops) - rust-lang#62808 (Revert "Disable stack probing for gnux32.") - rust-lang#62822 (Improve some pointer-related documentation) - rust-lang#62904 (Disable d32 on armv6 hf targets) - rust-lang#62907 (Initialize the MSP430 AsmParser) - rust-lang#62921 (Add method disambiguation help for trait implementation) - rust-lang#62942 (Use match ergonomics in Condvar documentation) Failed merges: r? @ghost

Turn `#[global_allocator]` into a regular attribute macro It was a 99% macro with exception of some diagnostic details. As a result of the change, `#[global_allocator]` now works in nested modules and even in nameless blocks. Fixes rust-lang#44113 Fixes rust-lang#58072

@ghost

Rollup of 15 pull requests Successful merges: - #60066 (Stabilize the type_name intrinsic in core::any) - #60938 (rustdoc: make #[doc(include)] relative to the containing file) - #61884 (Stablize Euclidean Modulo (feature euclidean_division)) - #61890 (Fix some sanity checks) - #62528 (Add joining slices of slices with a slice separator, not just a single item) - #62707 (Add tests for overlapping explicitly dropped locals in generators) - #62735 (Turn `#[global_allocator]` into a regular attribute macro) - #62822 (Improve some pointer-related documentation) - #62887 (Make the parser TokenStream more resilient after mismatched delimiter recovery) - #62921 (Add method disambiguation help for trait implementation) - #62930 (Add test for #51559) - #62942 (Use match ergonomics in Condvar documentation) - #62977 (Fix inconsistent highlight blocks.) - #62978 (Remove `cfg(bootstrap)` code for array implementations) - #62981 (Add note suggesting to borrow a String argument to find) Failed merges: - #62964 (clarify and unify some type test names) r? @ghost

Pkgsrc changes: * Adapt to the move of the implementation of random numbers. * Remove patch which is no longer relevant (Signals.inc) * Cross-build currently fails due to the still unresolved rust-lang/rust#62558, so bootstrap kits for 1.38.0 have to be built natively, and will follow shortly. * Bump bootstrap requirements to 1.37.0 except for armv7-unknown-netbsd-eabihf which I've neither managed to cross-build nor build natively. Upstream changes: Version 1.38.0 (2019-09-26) ========================== Language -------- - [The `#[global_allocator]` attribute can now be used in submodules.][62735] - [The `#[deprecated]` attribute can now be used on macros.][62042] Compiler -------- - [Added pipelined compilation support to `rustc`.][62766] This will improve compilation times in some cases. For further information please refer to the [_"Evaluating pipelined rustc compilation"_][pipeline-internals] thread. - [Added tier 3\* support for the `aarch64-uwp-windows-msvc`, `i686-uwp-windows-gnu`, `i686-uwp-windows-msvc`, `x86_64-uwp-windows-gnu`, and `x86_64-uwp-windows-msvc` targets.][60260] - [Added tier 3 support for the `armv7-unknown-linux-gnueabi` and `armv7-unknown-linux-musleabi` targets.][63107] - [Added tier 3 support for the `hexagon-unknown-linux-musl` target.][62814] - [Added tier 3 support for the `riscv32i-unknown-none-elf` target.][62784] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`ascii::EscapeDefault` now implements `Clone` and `Display`.][63421] - [Derive macros for prelude traits (e.g. `Clone`, `Debug`, `Hash`) are now available at the same path as the trait.][63056] (e.g. The `Clone` derive macro is available at `std::clone::Clone`). This also makes all built-in macros available in `std`/`core` root. e.g. `std::include_bytes!`. - [`str::Chars` now implements `Debug`.][63000] - [`slice::{concat, connect, join}` now accepts `&[T]` in addition to `&T`.][62528] - [`*const T` and `*mut T` now implement `marker::Unpin`.][62583] - [`Arc<[T]>` and `Rc<[T]>` now implement `FromIterator<T>`.][61953] - [Added euclidean remainder and division operations (`div_euclid`, `rem_euclid`) to all numeric primitives.][61884] Additionally `checked`, `overflowing`, and `wrapping` versions are available for all integer primitives. - [`thread::AccessError` now implements `Clone`, `Copy`, `Eq`, `Error`, and `PartialEq`.][61491] - [`iter::{StepBy, Peekable, Take}` now implement `DoubleEndedIterator`.][61457] Stabilized APIs --------------- - [`<*const T>::cast`] - [`<*mut T>::cast`] - [`Duration::as_secs_f32`] - [`Duration::as_secs_f64`] - [`Duration::div_duration_f32`] - [`Duration::div_duration_f64`] - [`Duration::div_f32`] - [`Duration::div_f64`] - [`Duration::from_secs_f32`] - [`Duration::from_secs_f64`] - [`Duration::mul_f32`] - [`Duration::mul_f64`] - [`any::type_name`] Cargo ----- - [Added pipelined compilation support to `cargo`.][cargo/7143] - [You can now pass the `--features` option multiple times to enable multiple features.][cargo/7084] Misc ---- - [`rustc` will now warn about some incorrect uses of `mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346] Compatibility Notes ------------------- - Unfortunately the [`x86_64-unknown-uefi` platform can not be built][62785] with rustc 1.39.0. - The [`armv7-unknown-linux-gnueabihf` platform is also known to have issues][62896] for certain crates such as libc. [60260]: rust-lang/rust#60260 [61457]: rust-lang/rust#61457 [61491]: rust-lang/rust#61491 [61884]: rust-lang/rust#61884 [61953]: rust-lang/rust#61953 [62042]: rust-lang/rust#62042 [62528]: rust-lang/rust#62528 [62583]: rust-lang/rust#62583 [62735]: rust-lang/rust#62735 [62766]: rust-lang/rust#62766 [62784]: rust-lang/rust#62784 [62785]: rust-lang/rust#62785 [62814]: rust-lang/rust#62814 [62896]: rust-lang/rust#62896 [63000]: rust-lang/rust#63000 [63056]: rust-lang/rust#63056 [63107]: rust-lang/rust#63107 [63346]: rust-lang/rust#63346 [63421]: rust-lang/rust#63421 [cargo/7084]: rust-lang/cargo#7084 [cargo/7143]: rust-lang/cargo#7143 [`<*const T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast [`<*mut T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast [`Duration::as_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f32 [`Duration::as_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f64 [`Duration::div_duration_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_duration_f32 [`Duration::div_duration_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_duration_f64 [`Duration::div_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f32 [`Duration::div_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f64 [`Duration::from_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f32 [`Duration::from_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f64 [`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32 [`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64 [`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html [forge-platform-support]: https://forge.rust-lang.org/platform-support.html [pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199

expand/resolve: Turn `#[derive]` into a regular macro attribute This PR turns `#[derive]` into a regular attribute macro declared in libcore and defined in `rustc_builtin_macros`, like it was previously done with other "active" attributes in rust-lang#62086, rust-lang#62735 and other PRs. This PR is also a continuation of rust-lang#65252, rust-lang#69870 and other PRs linked from them, which layed the ground for converting `#[derive]` specifically. `#[derive]` still asks `rustc_resolve` to resolve paths inside `derive(...)`, and `rustc_expand` gets those resolution results through some backdoor (which I'll try to address later), but otherwise `#[derive]` is treated as any other macro attributes, which simplifies the resolution-expansion infra pretty significantly. The change has several observable effects on language and library. Some of the language changes are **feature-gated** by [`feature(macro_attributes_in_derive_output)`](rust-lang#81119). #### Library - `derive` is now available through standard library as `{core,std}::prelude::v1::derive`. #### Language - `derive` now goes through name resolution, so it can now be renamed - `use derive as my_derive; #[my_derive(Debug)] struct S;`. - `derive` now goes through name resolution, so this resolution can fail in corner cases. Crater found one such regression, where import `use foo as derive` goes into a cycle with `#[derive(Something)]`. - **[feature-gated]** `#[derive]` is now expanded as any other attributes in left-to-right order. This allows to remove the restriction on other macro attributes following `#[derive]` (rust-lang/reference#566). The following macro attributes become a part of the derive's input (this is not a change, non-macro attributes following `#[derive]` were treated in the same way previously). - `#[derive]` is now expanded as any other attributes in left-to-right order. This means two derive attributes `#[derive(Foo)] #[derive(Bar)]` are now expanded separately rather than together. It doesn't generally make difference, except for esoteric cases. For example `#[derive(Foo)]` can now produce an import bringing `Bar` into scope, but previously both `Foo` and `Bar` were required to be resolved before expanding any of them. - **[feature-gated]** `#[derive()]` (with empty list in parentheses) actually becomes useful. For historical reasons `#[derive]` *fully configures* its input, eagerly evaluating `cfg` everywhere in its target, for example on fields. Expansion infra doesn't do that for other attributes, but now when macro attributes attributes are allowed to be written after `#[derive]`, it means that derive can *fully configure* items for them. ```rust #[derive()] #[my_attr] struct S { #[cfg(FALSE)] // this field in removed by `#[derive()]` and not observed by `#[my_attr]` field: u8 } ``` - `#[derive]` on some non-item targets is now prohibited. This was accidentally allowed as noop in the past, but was warned about since early 2018 (rust-lang#50092), despite that crater found a few such cases in unmaintained crates. - Derive helper attributes used before their introduction are now reported with a deprecation lint. This change is long overdue (since macro modularization, rust-lang#52226 (comment)), but it was hard to do without fixing expansion order for derives. The deprecation is tracked by rust-lang#79202. ```rust #[trait_helper] // warning: derive helper attribute is used before it is introduced #[derive(Trait)] struct S {} ``` Crater analysis: rust-lang#79078 (comment)

rust-highfive assigned nikomatsakis Jul 16, 2019

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This was referenced Jul 16, 2019

global_allocator can not not be defined inside module #44113

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ICE when static global allocator is defined in main function #58072

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Streamline Symbol, InternedString, and LocalInternedString. #60869

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petrochenkov changed the title ~~Turn #[global_allocator] into a regular attribute macro~~ [WIP] Turn #[global_allocator] into a regular attribute macro Jul 18, 2019

petrochenkov 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 Jul 18, 2019

petrochenkov force-pushed the galloc branch from ae23a76 to 1644a01 Compare July 18, 2019 23:51

petrochenkov changed the title ~~[WIP] Turn #[global_allocator] into a regular attribute macro~~ Turn #[global_allocator] into a regular attribute macro Jul 18, 2019

petrochenkov added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 18, 2019

petrochenkov force-pushed the galloc branch from 1644a01 to 602d3ea Compare July 19, 2019 00:05

rust-highfive assigned eddyb and unassigned nikomatsakis Jul 19, 2019

rust-highfive assigned alexcrichton and unassigned eddyb Jul 19, 2019

alexcrichton reviewed Jul 19, 2019

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Centril mentioned this pull request Jul 24, 2019

Rollup of 10 pull requests #62936

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Rollup of 13 pull requests #62960

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Rollup of 9 pull requests #62966

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Rollup of 15 pull requests #62990

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bors merged commit a0c2c64 into rust-lang:master Jul 26, 2019

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Comments for "https://os.phil-opp.com/heap-allocation/" phil-opp/blog_os#627

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phil-opp mentioned this pull request Jan 8, 2020

Move #[global_allocator] into allocator module phil-opp/blog_os#714

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expand/resolve: Turn #[derive] into a regular macro attribute #79078

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