bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #108820 - cjgillot:ensure-on-disk, r=oli-obk

Browse source 
Ensure value is on the on-disk cache before returning from `ensure()`.

The current logic for `ensure()` a query just checks that the node is green in the dependency graph.
However, a lot of places use `ensure()` to prevent the query from being called later. This is the case before stealing a query result.

If the query is actually green but the value is not available in the on-disk cache, `ensure` would return, but a subsequent call to the full query would run the code, and attempt to read from a stolen value.

This PR conforms the query system to the usage by checking whether the queried value is loadable from disk before returning.

Sadly, I can't manage to craft a proper test...

Should fix all instances of "attempted to read from stolen value".
This commit is contained in:
bors 2023-03-12 14:00:28 +00:00
commit f41927f309
10 changed files with 116 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

6
compiler/rustc_metadata/src/rmeta/encoder.rs
View file

@ -2050,13 +2050,13 @@ fn prefetch_mir(tcx: TyCtxt<'_>) {
let (encode_const, encode_opt) = should_encode_mir(tcx, def_id);
if encode_const {
tcx.ensure().mir_for_ctfe(def_id);
tcx.ensure_with_value().mir_for_ctfe(def_id);
}
if encode_opt {
tcx.ensure().optimized_mir(def_id);
tcx.ensure_with_value().optimized_mir(def_id);
}
if encode_opt || encode_const {
tcx.ensure().promoted_mir(def_id);
tcx.ensure_with_value().promoted_mir(def_id);
}
})
}