rust-lang/rust
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

Rollup merge of #143156 - folkertdev:fn-align-inherit-from-trait, r=workingjubilee

Browse Source 
inherit `#[align]` from trait method prototypes

````@workingjubilee```` this seems straightforward enough. Now that we're planning to make `-Cmin-function-alignment` a target modifier, I don't think there are any cross-crate complications here?

````@Jules-Bertholet```` is this the behavior you had in mind? In particular the inheritance of the attribute of a default impl is maybe a bit unintuitive at first? (but I think it's ok if that behavior is explicitly documented).

r? ghost
This commit is contained in:
Matthias Krüger
2025-07-01 04:25:35 +02:00
committed by GitHub
parent 74d1d59e7c bcf51051ed
commit 96fd669328
4 changed files with 93 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
compiler/rustc_codegen_ssa/src/codegen_attrs.rs
View File

@@ -1,6 +1,6 @@
use std::str::FromStr;
use rustc_abi::ExternAbi;
use rustc_abi::{Align, ExternAbi};
use rustc_ast::expand::autodiff_attrs::{AutoDiffAttrs, DiffActivity, DiffMode};
use rustc_ast::{LitKind, MetaItem, MetaItemInner, attr};
use rustc_attr_data_structures::{
@@ -395,6 +395,9 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
codegen_fn_attrs.alignment =
Ord::max(codegen_fn_attrs.alignment, tcx.sess.opts.unstable_opts.min_function_alignment);
// On trait methods, inherit the `#[align]` of the trait's method prototype.
codegen_fn_attrs.alignment = Ord::max(codegen_fn_attrs.alignment, tcx.inherited_align(did));
let inline_span;
(codegen_fn_attrs.inline, inline_span) = if let Some((inline_attr, span)) =
find_attr!(attrs, AttributeKind::Inline(i, span) => (*i, *span))
@@ -549,17 +552,26 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
codegen_fn_attrs
}
/// If the provided DefId is a method in a trait impl, return the DefId of the method prototype.
fn opt_trait_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
let impl_item = tcx.opt_associated_item(def_id)?;
match impl_item.container {
ty::AssocItemContainer::Impl => impl_item.trait_item_def_id,
_ => None,
}
}
/// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
/// applied to the method prototype.
fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
if let Some(impl_item) = tcx.opt_associated_item(def_id)
&& let ty::AssocItemContainer::Impl = impl_item.container
&& let Some(trait_item) = impl_item.trait_item_def_id
{
return tcx.codegen_fn_attrs(trait_item).flags.intersects(CodegenFnAttrFlags::TRACK_CALLER);
}
let Some(trait_item) = opt_trait_item(tcx, def_id) else { return false };
tcx.codegen_fn_attrs(trait_item).flags.intersects(CodegenFnAttrFlags::TRACK_CALLER)
}
false
/// If the provided DefId is a method in a trait impl, return the value of the `#[align]`
/// attribute on the method prototype (if any).
fn inherited_align<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<Align> {
tcx.codegen_fn_attrs(opt_trait_item(tcx, def_id)?).alignment
}
fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &hir::Attribute) -> Option<u16> {
@@ -727,5 +739,6 @@ fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> Option<AutoDiffAttrs> {
}
pub(crate) fn provide(providers: &mut Providers) {
*providers = Providers { codegen_fn_attrs, should_inherit_track_caller, ..*providers };
*providers =
Providers { codegen_fn_attrs, should_inherit_track_caller, inherited_align, ..*providers };
}