bjoernager/rust
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
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6
compiler/rustc_monomorphize/src/collector.rs
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@ -194,7 +194,7 @@ use rustc_target::abi::Size;
use std::path::PathBuf;
use crate::errors::{
EncounteredErrorWhileInstantiating, LargeAssignmentsLint, NoOptimizedMir, RecursionLimit,
self, EncounteredErrorWhileInstantiating, LargeAssignmentsLint, NoOptimizedMir, RecursionLimit,
TypeLengthLimit,
};
@ -1272,7 +1272,9 @@ impl<'v> RootCollector<'_, 'v> {
return;
};
let start_def_id = self.tcx.require_lang_item(LangItem::Start, None);
let Some(start_def_id) = self.tcx.lang_items().start_fn() else {
self.tcx.dcx().emit_fatal(errors::StartNotFound);
};
let main_ret_ty = self.tcx.fn_sig(main_def_id).no_bound_vars().unwrap().output();
// Given that `main()` has no arguments,