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error when using no_mangle on language items

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add suggestion on how to add a panic breakpoint

Co-authored-by: Pat Pannuto <pat.pannuto@gmail.com>
delete no_mangle from ui/panic-handler/panic-handler-wrong-location test

issue an error for the usage of #[no_mangle] on internal language items

delete the comments

add newline

rephrase note

Co-authored-by: bjorn3 <17426603+bjorn3@users.noreply.github.com>
update error not to leak implementation details

delete no_mangle_span

Co-authored-by: bjorn3 <17426603+bjorn3@users.noreply.github.com>
delete commented code
This commit is contained in:
Alexandru RADOVICI
2025-04-30 14:52:15 +03:00
parent 49e5e4e3a5
commit 07c7e5ffb3
6 changed files with 86 additions and 1 deletions
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30
compiler/rustc_codegen_ssa/src/codegen_attrs.rs
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@@ -87,6 +87,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
let mut link_ordinal_span = None;
let mut no_sanitize_span = None;
let mut mixed_export_name_no_mangle_lint_state = MixedExportNameAndNoMangleState::default();
let mut no_mangle_span = None;
for attr in attrs.iter() {
// In some cases, attribute are only valid on functions, but it's the `check_attr`
@@ -139,6 +140,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
}
sym::naked => codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED,
sym::no_mangle => {
no_mangle_span = Some(attr.span());
if tcx.opt_item_name(did.to_def_id()).is_some() {
codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
mixed_export_name_no_mangle_lint_state.track_no_mangle(
@@ -621,6 +623,34 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
}
check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
&& codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_MANGLE)
{
let lang_item =
lang_items::extract(attrs).map_or(None, |(name, _span)| LangItem::from_name(name));
let mut err = tcx
.dcx()
.struct_span_err(
no_mangle_span.unwrap_or_default(),
"`#[no_mangle]` cannot be used on internal language items",
)
.with_note("Rustc requires this item to have a specific mangled name.")
.with_span_label(tcx.def_span(did), "should be the internal language item");
if let Some(lang_item) = lang_item {
if let Some(link_name) = lang_item.link_name() {
err = err
.with_note("If you are trying to prevent mangling to ease debugging, many")
.with_note(format!(
"debuggers support a command such as `rbreak {link_name}` to"
))
.with_note(format!(
"match `.*{link_name}.*` instead of `break {link_name}` on a specific name"
))
}
}
err.emit();
}
// Any linkage to LLVM intrinsics for now forcibly marks them all as never
// unwinds since LLVM sometimes can't handle codegen which `invoke`s
// intrinsic functions.