`#[inline(required)]` by davidtwco · Pull Request #131687 · rust-lang/rust (original) (raw)

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Oct 14, 2024

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Adds #[inline(must)] and #[inline(required)] which is similar to always inlining but reports an error and warning respectively if the inlining was not possible, and which always attempts to inline required-annotated items, regardless of optimisation levels.

A job failed! Check out the build log: (web) (plain)

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COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
COPY host-x86_64/mingw-check/validate-error-codes.sh /scripts/

# NOTE: intentionally uses python2 for x.py so we can test it still works.
# validate-toolstate only runs in our CI, so it's ok for it to only support python3.
ENV SCRIPT TIDY_PRINT_DIFF=1 python2.7 ../x.py test \
           --stage 0 src/tools/tidy tidyselftest --extra-checks=py:lint,cpp:fmt
# This file is autogenerated by pip-compile with Python 3.10
# by the following command:
#
#    pip-compile --allow-unsafe --generate-hashes reuse-requirements.in
---
#4 [auth] library/ubuntu:pull token for registry-1.docker.io
#4 DONE 0.0s

#3 [internal] load metadata for docker.io/library/ubuntu:22.04
#3 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
 > [internal] load metadata for docker.io/library/ubuntu:22.04:
------
Dockerfile:1
--------------------
--------------------
   1 | >>> FROM ubuntu:22.04
   2 |     
   3 |     ARG DEBIAN_FRONTEND=noninteractive
--------------------
ERROR: failed to solve: ubuntu:22.04: failed to resolve source metadata for docker.io/library/ubuntu:22.04: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
#0 building with "ecstatic_colden" instance using docker-container driver

#1 [internal] load build definition from Dockerfile
#1 transferring dockerfile: 1.09kB done
#1 transferring dockerfile: 1.09kB done
#1 DONE 0.0s

#2 [internal] load metadata for docker.io/library/ubuntu:22.04
#2 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
 > [internal] load metadata for docker.io/library/ubuntu:22.04:
------
Dockerfile:1
--------------------
--------------------
   1 | >>> FROM ubuntu:22.04
   2 |     
   3 |     ARG DEBIAN_FRONTEND=noninteractive
--------------------
ERROR: failed to solve: ubuntu:22.04: failed to resolve source metadata for docker.io/library/ubuntu:22.04: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
#0 building with "ecstatic_colden" instance using docker-container driver

#1 [internal] load build definition from Dockerfile
#1 transferring dockerfile: 1.09kB done
#1 transferring dockerfile: 1.09kB done
#1 DONE 0.0s

#2 [internal] load metadata for docker.io/library/ubuntu:22.04
#2 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
 > [internal] load metadata for docker.io/library/ubuntu:22.04:
------
Dockerfile:1
--------------------
--------------------
   1 | >>> FROM ubuntu:22.04
   2 |     
   3 |     ARG DEBIAN_FRONTEND=noninteractive
--------------------
ERROR: failed to solve: ubuntu:22.04: failed to resolve source metadata for docker.io/library/ubuntu:22.04: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
#0 building with "ecstatic_colden" instance using docker-container driver

#1 [internal] load build definition from Dockerfile
#1 transferring dockerfile: 1.09kB done
#1 transferring dockerfile: 1.09kB done
#1 DONE 0.0s

#2 [internal] load metadata for docker.io/library/ubuntu:22.04
#2 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
 > [internal] load metadata for docker.io/library/ubuntu:22.04:
------
Dockerfile:1
--------------------
--------------------
   1 | >>> FROM ubuntu:22.04
   2 |     
   3 |     ARG DEBIAN_FRONTEND=noninteractive
--------------------
ERROR: failed to solve: ubuntu:22.04: failed to resolve source metadata for docker.io/library/ubuntu:22.04: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
#0 building with "ecstatic_colden" instance using docker-container driver

#1 [internal] load build definition from Dockerfile
#1 transferring dockerfile: 1.09kB done
#1 transferring dockerfile: 1.09kB done
#1 DONE 0.0s

#2 [internal] load metadata for docker.io/library/ubuntu:22.04
#2 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
 > [internal] load metadata for docker.io/library/ubuntu:22.04:
------
Dockerfile:1
--------------------
--------------------
   1 | >>> FROM ubuntu:22.04
   2 |     
   3 |     ARG DEBIAN_FRONTEND=noninteractive
--------------------
ERROR: failed to solve: ubuntu:22.04: failed to resolve source metadata for docker.io/library/ubuntu:22.04: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/ubuntu/manifests/sha256:58b87898e82351c6cf9cf5b9f3c20257bb9e2dcf33af051e12ce532d7f94e3fe: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
##[error]Process completed with exit code 1.
Post job cleanup.

CI failure isn't related to this PR - see Zulip

It's not fully baked yet but there were also some cute explorations around #[inline(usually)] in #130679 which may be interesting to you.

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It seems suspicious to use the MIR inliner to validate whether a function could be inlined, because the code may still be too polymorphic to determine if inlining is required or not. I'm tempted to believe that this code doesn't do the right thing:

trait Foo {
    fn method();
}

impl Foo for () {
    #[inline(required)]
    fn method() {
    }
}

fn poly<T: Foo>() {
    T::method();
}

fn main() {
    poly::<()>();
}

It seems suspicious to use the MIR inliner to validate whether a function could be inlined, because the code may still be too polymorphic to determine if inlining is required or not. I'm tempted to believe that this code doesn't do the right thing:
trait Foo {

   fn method();

}



impl Foo for () {

   #[inline(required)]

   fn method() {

   }

}



fn poly<T: Foo>() {

   T::method();

}



fn main() {

   poly::<()>();

}

Thanks for taking a look at this. After thinking about it some more and discussions on the RFC, I don't think this is the right approach, and will experiment with some alternative ideas :)

bors added a commit to rust-lang-ci/rust that referenced this pull request

Dec 9, 2024

mir_transform: implement #[rustc_force_inline]

Adds #[rustc_force_inline] which is similar to always inlining but reports an error if the inlining was not possible.

#[rustc_force_inline] can only be applied to free functions to guarantee that the MIR inliner will be able to resolve calls.
rustc_mir_transform::inline::Inline is refactored into two passes (Inline and ForceInline), sharing the vast majority of the implementation.
- rustc_mir_transform::inline::ForceInline can't be disabled so annotated items are always inlined.
- rustc_mir_transform::inline::ForceInline runs regardless of optimisation level.
#[rustc_force_inline] won't inline unless target features match, as with normal inlining.
MIR validation will ICE if a #[rustc_force_inline] isn't inlined, to guarantee that it will never be codegened independently. As a further guarantee, monomorphisation collection will always decide that #[rustc_force_inline] functions cannot be codegened locally.
Like other intrinsics, #[rustc_force_inline] annotated functions cannot be cast to function pointers.
As with other rustc attrs, this cannot be used by users, just within the compiler and standard library.
This is only implemented within rustc, so should avoid any limitations of LLVM's inlining.

It is intended that this attribute be used with intrinsics that must be inlined for security reasons. For example, pointer authentication intrinsics would allow Rust users to make use of pointer authentication instructions, but if these intrinsic functions were in the binary then they could be used as gadgets with ROP attacks, defeating the point of introducing them. We don't have any intrinsics like this today, but I expect to upstream some once a force inlining mechanism such as this is available.

cc rust-lang#131687 rust-lang/rfcs#3711 - this approach should resolve the concerns from these previous attempts

r? @saethlin

bors added a commit to rust-lang-ci/rust that referenced this pull request

Dec 12, 2024

mir_transform: implement #[rustc_force_inline]

Adds #[rustc_force_inline] which is similar to always inlining but reports an error if the inlining was not possible.

#[rustc_force_inline] can only be applied to free functions to guarantee that the MIR inliner will be able to resolve calls.
rustc_mir_transform::inline::Inline is refactored into two passes (Inline and ForceInline), sharing the vast majority of the implementation.
- rustc_mir_transform::inline::ForceInline can't be disabled so annotated items are always inlined.
- rustc_mir_transform::inline::ForceInline runs regardless of optimisation level.
#[rustc_force_inline] won't inline unless target features match, as with normal inlining.
MIR validation will ICE if a #[rustc_force_inline] isn't inlined, to guarantee that it will never be codegened independently. As a further guarantee, monomorphisation collection will always decide that #[rustc_force_inline] functions cannot be codegened locally.
Like other intrinsics, #[rustc_force_inline] annotated functions cannot be cast to function pointers.
As with other rustc attrs, this cannot be used by users, just within the compiler and standard library.
This is only implemented within rustc, so should avoid any limitations of LLVM's inlining.

cc rust-lang#131687 rust-lang/rfcs#3711 - this approach should resolve the concerns from these previous attempts

r? @saethlin

bors added a commit to rust-lang-ci/rust that referenced this pull request

Jan 10, 2025

mir_transform: implement #[rustc_force_inline]

Adds #[rustc_force_inline] which is similar to always inlining but reports an error if the inlining was not possible.

#[rustc_force_inline] can only be applied to free functions to guarantee that the MIR inliner will be able to resolve calls.
rustc_mir_transform::inline::Inline is refactored into two passes (Inline and ForceInline), sharing the vast majority of the implementation.
- rustc_mir_transform::inline::ForceInline can't be disabled so annotated items are always inlined.
- rustc_mir_transform::inline::ForceInline runs regardless of optimisation level.
#[rustc_force_inline] won't inline unless target features match, as with normal inlining.
MIR validation will ICE if a #[rustc_force_inline] isn't inlined, to guarantee that it will never be codegened independently. As a further guarantee, monomorphisation collection will always decide that #[rustc_force_inline] functions cannot be codegened locally.
Like other intrinsics, #[rustc_force_inline] annotated functions cannot be cast to function pointers.
As with other rustc attrs, this cannot be used by users, just within the compiler and standard library.
This is only implemented within rustc, so should avoid any limitations of LLVM's inlining.

cc rust-lang#131687 rust-lang/rfcs#3711 - this approach should resolve the concerns from these previous attempts

r? @saethlin

bors added a commit to rust-lang-ci/rust that referenced this pull request

Jan 10, 2025

mir_transform: implement #[rustc_force_inline]

Adds #[rustc_force_inline] which is similar to always inlining but reports an error if the inlining was not possible.

#[rustc_force_inline] can only be applied to free functions to guarantee that the MIR inliner will be able to resolve calls.
rustc_mir_transform::inline::Inline is refactored into two passes (Inline and ForceInline), sharing the vast majority of the implementation.
- rustc_mir_transform::inline::ForceInline can't be disabled so annotated items are always inlined.
- rustc_mir_transform::inline::ForceInline runs regardless of optimisation level.
#[rustc_force_inline] won't inline unless target features match, as with normal inlining.
MIR validation will ICE if a #[rustc_force_inline] isn't inlined, to guarantee that it will never be codegened independently. As a further guarantee, monomorphisation collection will always decide that #[rustc_force_inline] functions cannot be codegened locally.
Like other intrinsics, #[rustc_force_inline] annotated functions cannot be cast to function pointers.
As with other rustc attrs, this cannot be used by users, just within the compiler and standard library.
This is only implemented within rustc, so should avoid any limitations of LLVM's inlining.

cc rust-lang#131687 rust-lang/rfcs#3711 - this approach should resolve the concerns from these previous attempts

r? @saethlin

#[inline(required)] by davidtwco · Pull Request #131687 · rust-lang/rust (original) (raw)

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`#[inline(required)]` by davidtwco · Pull Request #131687 · rust-lang/rust (original) (raw)