#[inline(required)]
#131687
Closed
#[inline(required)]
#131687
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rustbot
added
S-waiting-on-review
This comment was marked as resolved.
This comment was marked as resolved.
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.
davidtwco
force-pushed
the
required-inlining
branch
from
0c8e080 to
e83d77f
Compare
|
A job failed! Check out the build log: (web) (plain) Click to see the possible cause of the failure (guessed by this bot) |
|
CI failure isn't related to this PR - see Zulip |
|
It's not fully baked yet but there were also some cute explorations around |
There was a problem hiding this comment.
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. 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
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. 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
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. 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`
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
See rust-lang/rfcs#3711.