bjoernager/rust
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Stop mentioning internal lang items in no_std binary errors

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When writing a no_std binary, you'll be greeted with nonsensical errors
mentioning lang items like eh_personality and start. That's pretty bad
because it makes you think that you need to define them somewhere! But
oh no, now you're getting the `internal_features` lint telling you that
you shouldn't use them! But you need a no_std binary! What now?

No problem! Writing a no_std binary is super easy. Just use panic=abort
and supply your own platform specific entrypoint symbol (like `main`)
and you're good to go. Would be nice if the compiler told you that,
right?

This makes it so that it does do that.
This commit is contained in:
Nilstrieb 2023-10-02 12:32:31 +00:00
parent a2d9d73e60
commit da26317a8a
16 changed files with 85 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

6
compiler/rustc_passes/src/errors.rs
View file

@ -812,6 +812,12 @@ pub struct UnknownExternLangItem {
#[diag(passes_missing_panic_handler)]
pub struct MissingPanicHandler;
#[derive(Diagnostic)]
#[diag(passes_panic_unwind_without_std)]
#[help]
#[note]
pub struct PanicUnwindWithoutStd;
#[derive(Diagnostic)]
#[diag(passes_missing_lang_item)]
#[note]

6
compiler/rustc_passes/src/weak_lang_items.rs
View file

@ -9,7 +9,9 @@ use rustc_middle::middle::lang_items::required;
use rustc_middle::ty::TyCtxt;
use rustc_session::config::CrateType;
use crate::errors::{MissingLangItem, MissingPanicHandler, UnknownExternLangItem};
use crate::errors::{
MissingLangItem, MissingPanicHandler, PanicUnwindWithoutStd, UnknownExternLangItem,
};
/// Checks the crate for usage of weak lang items, returning a vector of all the
/// language items required by this crate, but not defined yet.
@ -76,6 +78,8 @@ fn verify(tcx: TyCtxt<'_>, items: &lang_items::LanguageItems) {
if missing.contains(&item) && required(tcx, item) && items.get(item).is_none() {
if item == LangItem::PanicImpl {
tcx.dcx().emit_err(MissingPanicHandler);
} else if item == LangItem::EhPersonality {
tcx.dcx().emit_err(PanicUnwindWithoutStd);
} else {
tcx.dcx().emit_err(MissingLangItem { name: item.name() });
}