Auto merge of #135167 - mzacho:depth-limit-const-eval-query, r=oli-obk

Depth limit const eval query

Currently the const-eval query doesn't have a recursion limit or timeout, causing the complier to freeze in an infinite loop, see #125718. This PR depth limits the `eval_to_const_value_raw` query (with the [`recursion_limit`](https://doc.rust-lang.org/reference/attributes/limits.html) attribute) and improves the diagnostics for query overflow errors, so spans are reported for other dep kinds than `layout_of` (e.g. `eval_to_const_value_raw`).

fixes #125718
fixes #114192

6 files changed, 20 insertions, 28 deletions

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 7d334847d44..5516770726d 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1243,6 +1243,7 @@ rustc_queries! {
             "simplifying constant for the type system `{}`",
             key.value.display(tcx)
         }
+        depth_limit
         cache_on_disk_if { true }
     }
 
diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index 1b12af62ea5..46ec538735a 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -27,7 +27,7 @@ use rustc_query_system::query::{
     QueryCache, QueryConfig, QueryContext, QueryJobId, QueryMap, QuerySideEffects, QueryStackFrame,
     force_query,
 };
-use rustc_query_system::{LayoutOfDepth, QueryOverflow};
+use rustc_query_system::{QueryOverflow, QueryOverflowNote};
 use rustc_serialize::{Decodable, Encodable};
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
@@ -153,14 +153,7 @@ impl QueryContext for QueryCtxt<'_> {
     }
 
     fn depth_limit_error(self, job: QueryJobId) {
-        let mut span = None;
-        let mut layout_of_depth = None;
-        if let Some((info, depth)) =
-            job.try_find_layout_root(self.collect_active_jobs(), dep_kinds::layout_of)
-        {
-            span = Some(info.job.span);
-            layout_of_depth = Some(LayoutOfDepth { desc: info.query.description, depth });
-        }
+        let (info, depth) = job.find_dep_kind_root(self.collect_active_jobs());
 
         let suggested_limit = match self.recursion_limit() {
             Limit(0) => Limit(2),
@@ -168,8 +161,8 @@ impl QueryContext for QueryCtxt<'_> {
         };
 
         self.sess.dcx().emit_fatal(QueryOverflow {
-            span,
-            layout_of_depth,
+            span: info.job.span,
+            note: QueryOverflowNote { desc: info.query.description, depth },
             suggested_limit,
             crate_name: self.crate_name(LOCAL_CRATE),
         });
diff --git a/compiler/rustc_query_system/messages.ftl b/compiler/rustc_query_system/messages.ftl
index d7ab7557511..f48dc60afa0 100644
--- a/compiler/rustc_query_system/messages.ftl
+++ b/compiler/rustc_query_system/messages.ftl
@@ -21,7 +21,7 @@ query_system_increment_compilation = internal compiler error: encountered increm
 query_system_increment_compilation_note1 = Please follow the instructions below to create a bug report with the provided information
 query_system_increment_compilation_note2 = See <https://github.com/rust-lang/rust/issues/84970> for more information
 
-query_system_layout_of_depth = query depth increased by {$depth} when {$desc}
+query_system_overflow_note = query depth increased by {$depth} when {$desc}
 
 query_system_query_overflow = queries overflow the depth limit!
     .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
diff --git a/compiler/rustc_query_system/src/error.rs b/compiler/rustc_query_system/src/error.rs
index 860f2e66915..5108ecaeea3 100644
--- a/compiler/rustc_query_system/src/error.rs
+++ b/compiler/rustc_query_system/src/error.rs
@@ -82,16 +82,16 @@ pub(crate) struct IncrementCompilation {
 #[diag(query_system_query_overflow)]
 pub struct QueryOverflow {
     #[primary_span]
-    pub span: Option<Span>,
+    pub span: Span,
     #[subdiagnostic]
-    pub layout_of_depth: Option<LayoutOfDepth>,
+    pub note: QueryOverflowNote,
     pub suggested_limit: Limit,
     pub crate_name: Symbol,
 }
 
 #[derive(Subdiagnostic)]
-#[note(query_system_layout_of_depth)]
-pub struct LayoutOfDepth {
+#[note(query_system_overflow_note)]
+pub struct QueryOverflowNote {
     pub desc: String,
     pub depth: usize,
 }
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index a85e8a55a21..ee984095ad8 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -16,7 +16,7 @@ pub mod ich;
 pub mod query;
 mod values;
 
-pub use error::{HandleCycleError, LayoutOfDepth, QueryOverflow};
+pub use error::{HandleCycleError, QueryOverflow, QueryOverflowNote};
 pub use values::Value;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 2a7d759ab35..3e179c61f39 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -15,7 +15,7 @@ use rustc_span::{DUMMY_SP, Span};
 use crate::dep_graph::DepContext;
 use crate::error::CycleStack;
 use crate::query::plumbing::CycleError;
-use crate::query::{DepKind, QueryContext, QueryStackFrame};
+use crate::query::{QueryContext, QueryStackFrame};
 
 /// Represents a span and a query key.
 #[derive(Clone, Debug)]
@@ -136,20 +136,18 @@ impl QueryJobId {
 
     #[cold]
     #[inline(never)]
-    pub fn try_find_layout_root(
-        &self,
-        query_map: QueryMap,
-        layout_of_kind: DepKind,
-    ) -> Option<(QueryJobInfo, usize)> {
-        let mut last_layout = None;
-        let mut current_id = Some(*self);
-        let mut depth = 0;
+    pub fn find_dep_kind_root(&self, query_map: QueryMap) -> (QueryJobInfo, usize) {
+        let mut depth = 1;
+        let info = query_map.get(&self).unwrap();
+        let dep_kind = info.query.dep_kind;
+        let mut current_id = info.job.parent;
+        let mut last_layout = (info.clone(), depth);
 
         while let Some(id) = current_id {
             let info = query_map.get(&id).unwrap();
-            if info.query.dep_kind == layout_of_kind {
+            if info.query.dep_kind == dep_kind {
                 depth += 1;
-                last_layout = Some((info.clone(), depth));
+                last_layout = (info.clone(), depth);
             }
             current_id = info.job.parent;
         }