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Rollup merge of #91504 - cynecx:used_retain, r=nikic

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`#[used(linker)]` attribute

See https://github.com/dtolnay/linkme/issues/41#issuecomment-927255631.
This commit is contained in:
Matthias Krüger 2022-02-09 23:29:56 +01:00 • committed by GitHub
commit 3f4aaf4f2e
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16 changed files with 182 additions and 4 deletions
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34
compiler/rustc_passes/src/check_attr.rs
View file

@ -1741,12 +1741,46 @@ impl CheckAttrVisitor<'_> {
}
fn check_used(&self, attrs: &[Attribute], target: Target) {
let mut used_linker_span = None;
let mut used_compiler_span = None;
for attr in attrs {
if attr.has_name(sym::used) && target != Target::Static {
self.tcx
.sess
.span_err(attr.span, "attribute must be applied to a `static` variable");
}
let inner = attr.meta_item_list();
match inner.as_deref() {
Some([item]) if item.has_name(sym::linker) => {
if used_linker_span.is_none() {
used_linker_span = Some(attr.span);
}
}
Some([item]) if item.has_name(sym::compiler) => {
if used_compiler_span.is_none() {
used_compiler_span = Some(attr.span);
}
}
Some(_) => {
// This error case is handled in rustc_typeck::collect.
}
None => {
// Default case (compiler) when arg isn't defined.
if used_compiler_span.is_none() {
used_compiler_span = Some(attr.span);
}
}
}
}
if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
let spans = vec![linker_span, compiler_span];
self.tcx
.sess
.struct_span_err(
spans,
"`used(compiler)` and `used(linker)` can't be used together",
)
.emit();
}
}

5
compiler/rustc_passes/src/dead.rs
View file

@ -466,7 +466,10 @@ fn has_allow_dead_code_or_lang_attr(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
// #[used], #[no_mangle], #[export_name], etc also keeps the item alive
// forcefully, e.g., for placing it in a specific section.
if cg_attrs.contains_extern_indicator() || cg_attrs.flags.contains(CodegenFnAttrFlags::USED) {
if cg_attrs.contains_extern_indicator()
|| cg_attrs.flags.contains(CodegenFnAttrFlags::USED)
|| cg_attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER)
{
return true;
}