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Various improvements to entrypoint code

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This moves some code around and adds some documentation comments to make
it easier to understand what's going on with the entrypoint logic, which
is a bit complicated.

The only change in behavior is consolidating the error messages for
unix_sigpipe to make the code slightly simpler.
This commit is contained in:
Nilstrieb 2024-05-01 17:37:22 +02:00
parent 6d721dd0b8
commit 1572c0dcd7
5 changed files with 49 additions and 43 deletions
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42
compiler/rustc_passes/src/entry.rs
View file

@ -18,10 +18,10 @@ use crate::errors::{
struct EntryContext<'tcx> {
tcx: TyCtxt<'tcx>,
/// The function that has attribute named `main`.
attr_main_fn: Option<(LocalDefId, Span)>,
/// The function has the `#[rustc_main]` attribute.
rustc_main_fn: Option<(LocalDefId, Span)>,
/// The function that has the attribute 'start' on it.
/// The function that has the attribute `#[start]` on it.
start_fn: Option<(LocalDefId, Span)>,
/// The functions that one might think are `main` but aren't, e.g.
@ -42,10 +42,10 @@ fn entry_fn(tcx: TyCtxt<'_>, (): ()) -> Option<(DefId, EntryFnType)> {
}
let mut ctxt =
EntryContext { tcx, attr_main_fn: None, start_fn: None, non_main_fns: Vec::new() };
EntryContext { tcx, rustc_main_fn: None, start_fn: None, non_main_fns: Vec::new() };
for id in tcx.hir().items() {
find_item(id, &mut ctxt);
check_and_search_item(id, &mut ctxt);
}
configure_main(tcx, &ctxt)
@ -56,7 +56,16 @@ fn attr_span_by_symbol(ctxt: &EntryContext<'_>, id: ItemId, sym: Symbol) -> Opti
attr::find_by_name(attrs, sym).map(|attr| attr.span)
}
fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
fn check_and_search_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
if !matches!(ctxt.tcx.def_kind(id.owner_id), DefKind::Fn) {
for attr in [sym::start, sym::rustc_main] {
if let Some(span) = attr_span_by_symbol(ctxt, id, attr) {
ctxt.tcx.dcx().emit_err(AttrOnlyInFunctions { span, attr });
}
}
return;
}
let at_root = ctxt.tcx.opt_local_parent(id.owner_id.def_id) == Some(CRATE_DEF_ID);
let attrs = ctxt.tcx.hir().attrs(id.hir_id());
@ -65,26 +74,20 @@ fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
at_root,
ctxt.tcx.opt_item_name(id.owner_id.to_def_id()),
);
match entry_point_type {
EntryPointType::None => (),
_ if !matches!(ctxt.tcx.def_kind(id.owner_id), DefKind::Fn) => {
for attr in [sym::start, sym::rustc_main] {
if let Some(span) = attr_span_by_symbol(ctxt, id, attr) {
ctxt.tcx.dcx().emit_err(AttrOnlyInFunctions { span, attr });
}
}
}
EntryPointType::MainNamed => (),
EntryPointType::None => {}
EntryPointType::MainNamed => {}
EntryPointType::OtherMain => {
ctxt.non_main_fns.push(ctxt.tcx.def_span(id.owner_id));
}
EntryPointType::RustcMainAttr => {
if ctxt.attr_main_fn.is_none() {
ctxt.attr_main_fn = Some((id.owner_id.def_id, ctxt.tcx.def_span(id.owner_id)));
if ctxt.rustc_main_fn.is_none() {
ctxt.rustc_main_fn = Some((id.owner_id.def_id, ctxt.tcx.def_span(id.owner_id)));
} else {
ctxt.tcx.dcx().emit_err(MultipleRustcMain {
span: ctxt.tcx.def_span(id.owner_id.to_def_id()),
first: ctxt.attr_main_fn.unwrap().1,
first: ctxt.rustc_main_fn.unwrap().1,
additional: ctxt.tcx.def_span(id.owner_id.to_def_id()),
});
}
@ -107,10 +110,11 @@ fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) -> Option<(DefId, EntryFnType)> {
if let Some((def_id, _)) = visitor.start_fn {
Some((def_id.to_def_id(), EntryFnType::Start))
} else if let Some((local_def_id, _)) = visitor.attr_main_fn {
} else if let Some((local_def_id, _)) = visitor.rustc_main_fn {
let def_id = local_def_id.to_def_id();
Some((def_id, EntryFnType::Main { sigpipe: sigpipe(tcx) }))
} else {
// The actual resolution of main happens in the resolver, this here
if let Some(main_def) = tcx.resolutions(()).main_def
&& let Some(def_id) = main_def.opt_fn_def_id()
{