From b7cc99142ad0cfe47e2fe9f7a82eaf5b672c0573 Mon Sep 17 00:00:00 2001 From: Michael Woerister Date: Thu, 7 Oct 2021 11:29:01 +0200 Subject: Turn tcx.vtable_allocation() into a query. --- src/test/incremental/reorder_vtable.rs | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'src/test') diff --git a/src/test/incremental/reorder_vtable.rs b/src/test/incremental/reorder_vtable.rs index a550fe6f01c..8dacba63351 100644 --- a/src/test/incremental/reorder_vtable.rs +++ b/src/test/incremental/reorder_vtable.rs @@ -1,5 +1,10 @@ // revisions:rpass1 rpass2 +// This test case makes sure re-order the methods in a vtable will +// trigger recompilation of codegen units that instantiate it. +// +// See https://github.com/rust-lang/rust/issues/89598 + trait Foo { #[cfg(rpass1)] fn method1(&self) -> u32; @@ -16,12 +21,21 @@ impl Foo for u32 { } fn main() { + // Before #89598 was fixed, the vtable allocation would be cached during + // a MIR optimization pass and then the codegen pass for the main object + // file would not register a dependency on it (because of the missing + // dep-tracking). + // + // In the rpass2 session, the main object file would not be re-compiled, + // thus the mod1::foo(x) call would pass in an outdated vtable, while the + // mod1 object would expect the new, re-ordered vtable, resulting in a + // call to the wrong method. let x: &dyn Foo = &0u32; assert_eq!(mod1::foo(x), 17); } mod mod1 { - pub fn foo(x: &dyn super::Foo) -> u32 { + pub(super) fn foo(x: &dyn super::Foo) -> u32 { x.method1() } } -- cgit 1.4.1-3-g733a5