From 00cde6d4b94bba23ad06b352bc589805574f62b2 Mon Sep 17 00:00:00 2001 From: Joshua Nelson Date: Sun, 18 Sep 2022 16:35:48 -0500 Subject: Move the `codegen_unit` debug assert from `rustc_query_system` to `query_impl` This allows removing a function from the `DepKind` trait. --- compiler/rustc_query_impl/src/plumbing.rs | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'compiler/rustc_query_impl') diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs index d819f4774d5..ac95c8edf3f 100644 --- a/compiler/rustc_query_impl/src/plumbing.rs +++ b/compiler/rustc_query_impl/src/plumbing.rs @@ -380,6 +380,24 @@ where Q::Key: DepNodeParams>, Q::Value: Value>, { + // We must avoid ever having to call `force_from_dep_node()` for a + // `DepNode::codegen_unit`: + // Since we cannot reconstruct the query key of a `DepNode::codegen_unit`, we + // would always end up having to evaluate the first caller of the + // `codegen_unit` query that *is* reconstructible. This might very well be + // the `compile_codegen_unit` query, thus re-codegenning the whole CGU just + // to re-trigger calling the `codegen_unit` query with the right key. At + // that point we would already have re-done all the work we are trying to + // avoid doing in the first place. + // The solution is simple: Just explicitly call the `codegen_unit` query for + // each CGU, right after partitioning. This way `try_mark_green` will always + // hit the cache instead of having to go through `force_from_dep_node`. + // This assertion makes sure, we actually keep applying the solution above. + debug_assert!( + dep_node.kind != DepKind::codegen_unit, + "calling force_from_dep_node() on DepKind::codegen_unit" + ); + if let Some(key) = Q::Key::recover(tcx, &dep_node) { #[cfg(debug_assertions)] let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered(); -- cgit 1.4.1-3-g733a5