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Auto merge of #98570 - SparrowLii:deadlock, r=cjgillot

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get rid of `tcx` in deadlock handler when parallel compilation

This is a very obscure and hard-to-trace problem that affects thread scheduling. If we copy `tcx` to the deadlock handler thread, it will perform unpredictable behavior and cause very weird problems when executing `try_collect_active_jobs`(For example, the deadlock handler thread suddenly preempts the content of the blocked worker thread and executes the unknown judgment branch, like #94654).
Fortunately we can avoid this behavior by precomputing `query_map`. This change fixes the following ui tests failure on my environment when set `parallel-compiler = true`:
```
    [ui] src/test\ui\async-await\no-const-async.rs
    [ui] src/test\ui\infinite\infinite-struct.rs
    [ui] src/test\ui\infinite\infinite-tag-type-recursion.rs
    [ui] src/test\ui\issues\issue-3008-1.rs
    [ui] src/test\ui\issues\issue-3008-2.rs
    [ui] src/test\ui\issues\issue-32326.rs
    [ui] src/test\ui\issues\issue-57271.rs
    [ui] src/test\ui\issues\issue-72554.rs
    [ui] src/test\ui\parser\fn-header-semantic-fail.rs
    [ui] src/test\ui\union\union-nonrepresentable.rs
```

Updates #75760
Fixes #94654
This commit is contained in:
bors 2022-07-03 02:05:14 +00:00
commit 8c52a83c45
4 changed files with 9 additions and 21 deletions
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3
compiler/rustc_query_system/src/query/job.rs
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@ -492,14 +492,13 @@ fn remove_cycle(
/// There may be multiple cycles involved in a deadlock, so this searches
/// all active queries for cycles before finally resuming all the waiters at once.
#[cfg(parallel_compiler)]
pub fn deadlock<CTX: QueryContext>(tcx: CTX, registry: &rayon_core::Registry) {
pub fn deadlock(query_map: QueryMap, registry: &rayon_core::Registry) {
let on_panic = OnDrop(|| {
eprintln!("deadlock handler panicked, aborting process");
process::abort();
});
let mut wakelist = Vec::new();
let query_map = tcx.try_collect_active_jobs().unwrap();
let mut jobs: Vec<QueryJobId> = query_map.keys().cloned().collect();
let mut found_cycle = false;