Auto merge of #120675 - oli-obk:intrinsics3.0, r=pnkfelix

Add a scheme for moving away from `extern "rust-intrinsic"` entirely

All `rust-intrinsic`s can become free functions now, either with a fallback body, or with a dummy body and an attribute, requiring backends to actually implement the intrinsic.

This PR demonstrates the dummy-body scheme with the `vtable_size` intrinsic.

cc https://github.com/rust-lang/rust/issues/63585

follow-up to #120500

MCP at https://github.com/rust-lang/compiler-team/issues/720
This commit is contained in:
bors 2024-03-05 00:13:01 +00:00
commit 415b1f1fa7

View File

@ -334,7 +334,7 @@ fn check_terminator<'tcx>(
// within const fns. `transmute` is allowed in all other const contexts.
// This won't really scale to more intrinsics or functions. Let's allow const
// transmutes in const fn before we add more hacks to this.
if matches!(tcx.intrinsic(fn_def_id), Some(sym::transmute)) {
if tcx.is_intrinsic(fn_def_id, sym::transmute) {
return Err((
span,
"can only call `transmute` from const items, not `const fn`".into(),