This ensures that the entry function is never elided due to inlining, even with `inline(always)`. Fixes #47783.
There were a couple of possible ways of addressing this issue; I simply picked the one that seemed most direct. A warning could be appropriate, but considering using inlining hints in other places it doesn't apply also throws no warnings, and it seems like an edge case anyway, I haven't added one for now.
match *self.as_mono_item() {
MonoItem::Fn(ref instance) => {
+ let entry_def_id =
+ tcx.sess.entry_fn.borrow().map(|(id, _)| tcx.hir.local_def_id(id));
// If this function isn't inlined or otherwise has explicit
// linkage, then we'll be creating a globally shared version.
if self.explicit_linkage(tcx).is_some() ||
- !instance.def.requires_local(tcx)
+ !instance.def.requires_local(tcx) ||
+ Some(instance.def_id()) == entry_def_id
{
return InstantiationMode::GloballyShared { may_conflict: false }
}
--- /dev/null
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[inline(always)]
+fn main() {}