Auto merge of #71131 - pnkfelix:issue-69798-dont-reuse-post-lto-products-when-exports-change, r=nagisa

Do not reuse post LTO products when exports change

Do not reuse post lto products when exports change

Generalizes code from PR #67020, which handled case when imports change.

Fix #69798

2 files changed, 52 insertions, 0 deletions

diff --git a/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs b/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs
new file mode 100644
index 00000000000..4d48a5f0ac5
--- /dev/null
+++ b/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs
@@ -0,0 +1,26 @@
+// revisions: cfail1 cfail2
+// build-pass
+
+// rust-lang/rust#69798:
+//
+// This is analgous to cgu_invalidated_when_import_added, but it covers a
+// problem uncovered where a change to the *export* set caused a link failure
+// when reusing post-LTO optimized object code.
+
+pub struct Foo {}
+impl Drop for Foo {
+    fn drop(&mut self) {
+        println!("Dropping Foo");
+    }
+}
+#[no_mangle]
+pub extern "C" fn run() {
+    thread_local! { pub static FOO : Foo = Foo { } ; }
+
+    #[cfg(cfail2)]
+    {
+        FOO.with(|_f| ())
+    }
+}
+
+pub fn main() { run() }
diff --git a/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs b/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs
new file mode 100644
index 00000000000..e85b4856f3a
--- /dev/null
+++ b/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs
@@ -0,0 +1,26 @@
+// revisions: cfail1 cfail2
+// build-pass
+
+// rust-lang/rust#69798:
+//
+// This is analgous to cgu_invalidated_when_export_added, but it covers the
+// other direction. This is analogous to cgu_invalidated_when_import_added: we
+// include it, because it may uncover bugs in variant implementation strategies.
+
+pub struct Foo {}
+impl Drop for Foo {
+    fn drop(&mut self) {
+        println!("Dropping Foo");
+    }
+}
+#[no_mangle]
+pub extern "C" fn run() {
+    thread_local! { pub static FOO : Foo = Foo { } ; }
+
+    #[cfg(cfail1)]
+    {
+        FOO.with(|_f| ())
+    }
+}
+
+pub fn main() { run() }