bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

CTFE: exposing pointers and calling extern fn doesn't need an RFC, it is just impossible

Browse source
This commit is contained in:
Ralf Jung 2022-08-28 13:13:13 -04:00
parent ee285eab69
commit a9f9145b09
4 changed files with 8 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

8
compiler/rustc_const_eval/src/const_eval/machine.rs
View file

@ -269,9 +269,10 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
);
throw_inval!(AlreadyReported(guar));
} else {
// `find_mir_or_eval_fn` checks that this is a const fn before even calling us,
// so this should be unreachable.
let path = ecx.tcx.def_path_str(def.did);
Err(ConstEvalErrKind::NeedsRfc(format!("calling extern function `{}`", path))
.into())
bug!("trying to call extern function `{path}` at compile-time");
}
}
_ => Ok(ecx.tcx.instance_mir(instance)),
@ -469,7 +470,8 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
_ecx: &mut InterpCx<'mir, 'tcx, Self>,
_ptr: Pointer<AllocId>,
) -> InterpResult<'tcx> {
Err(ConstEvalErrKind::NeedsRfc("exposing pointers".to_string()).into())
// This is only reachable with -Zunleash-the-miri-inside-of-you.
throw_unsup_format!("exposing pointers is not possible at compile-time")
}
#[inline(always)]

1
compiler/rustc_const_eval/src/interpret/machine.rs
View file

@ -490,6 +490,7 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
) -> InterpResult<$tcx, Pointer<Option<AllocId>>> {
// Allow these casts, but make the pointer not dereferenceable.
// (I.e., they behave like transmutation.)
// This is correct because no pointers can ever be exposed in compile-time evaluation.
Ok(Pointer::from_addr(addr))
}