diff --git a/src/librustc/ty/instance.rs b/src/librustc/ty/instance.rs
index c9ad8707a7454..13d58ea73ac6b 100644
--- a/src/librustc/ty/instance.rs
+++ b/src/librustc/ty/instance.rs
@@ -381,6 +381,32 @@ impl<'tcx> Instance<'tcx> {
         Instance { def, substs }
     }
 
+    /// FIXME(#69925) Depending on the kind of `InstanceDef`, the MIR body associated with an
+    /// instance is expressed in terms of the generic parameters of `self.def_id()`, and in other
+    /// cases the MIR body is expressed in terms of the types found in the substitution array.
+    /// In the former case, we want to substitute those generic types and replace them with the
+    /// values from the substs when monomorphizing the function body. But in the latter case, we
+    /// don't want to do that substitution, since it has already been done effectively.
+    ///
+    /// This function returns `Some(substs)` in the former case and None otherwise -- i.e., if
+    /// this function returns `None`, then the MIR body does not require substitution during
+    /// monomorphization.
+    pub fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> {
+        match self.def {
+            InstanceDef::CloneShim(..)
+            | InstanceDef::DropGlue(_, Some(_)) => None,
+            InstanceDef::ClosureOnceShim { .. }
+            | InstanceDef::DropGlue(..)
+            // FIXME(#69925): `FnPtrShim` should be in the other branch.
+            | InstanceDef::FnPtrShim(..)
+            | InstanceDef::Item(_)
+            | InstanceDef::Intrinsic(..)
+            | InstanceDef::ReifyShim(..)
+            | InstanceDef::Virtual(..)
+            | InstanceDef::VtableShim(..) => Some(self.substs),
+        }
+    }
+
     pub fn is_vtable_shim(&self) -> bool {
         if let InstanceDef::VtableShim(..) = self.def { true } else { false }
     }
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 041dfc7d169a4..6d28796b34847 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -780,8 +780,8 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                     present_first @ Some(_) => present_first,
                     // Uninhabited because it has no variants, or only absent ones.
                     None if def.is_enum() => return tcx.layout_raw(param_env.and(tcx.types.never)),
-                    // if it's a struct, still compute a layout so that we can still compute the
-                    // field offsets
+                    // If it's a struct, still compute a layout so that we can still compute the
+                    // field offsets.
                     None => Some(VariantIdx::new(0)),
                 };
 
@@ -1987,7 +1987,15 @@ where
 {
     fn for_variant(this: TyLayout<'tcx>, cx: &C, variant_index: VariantIdx) -> TyLayout<'tcx> {
         let details = match this.variants {
-            Variants::Single { index } if index == variant_index => this.details,
+            Variants::Single { index }
+                // If all variants but one are uninhabited, the variant layout is the enum layout.
+                if index == variant_index &&
+                // Don't confuse variants of uninhabited enums with the enum itself.
+                // For more details see https://github.com/rust-lang/rust/issues/69763.
+                this.fields != FieldPlacement::Union(0) =>
+            {
+                this.details
+            }
 
             Variants::Single { index } => {
                 // Deny calling for_variant more than once for non-Single enums.
diff --git a/src/librustc/ty/query/caches.rs b/src/librustc/ty/query/caches.rs
index efc2804bd4d59..a11b3bcba3ed3 100644
--- a/src/librustc/ty/query/caches.rs
+++ b/src/librustc/ty/query/caches.rs
@@ -1,5 +1,4 @@
 use crate::dep_graph::DepNodeIndex;
-use crate::ty::query::config::QueryAccessors;
 use crate::ty::query::plumbing::{QueryLookup, QueryState, QueryStateShard};
 use crate::ty::TyCtxt;
 
@@ -7,39 +6,43 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sharded::Sharded;
 use std::default::Default;
 use std::hash::Hash;
+use std::marker::PhantomData;
 
 pub(crate) trait CacheSelector<K, V> {
-    type Cache: QueryCache<K, V>;
+    type Cache: QueryCache<Key = K, Value = V>;
 }
 
-pub(crate) trait QueryCache<K, V>: Default {
+pub(crate) trait QueryCache: Default {
+    type Key;
+    type Value;
     type Sharded: Default;
 
     /// Checks if the query is already computed and in the cache.
     /// It returns the shard index and a lock guard to the shard,
     /// which will be used if the query is not in the cache and we need
     /// to compute it.
-    fn lookup<'tcx, R, GetCache, OnHit, OnMiss, Q>(
+    fn lookup<'tcx, R, GetCache, OnHit, OnMiss>(
         &self,
-        state: &'tcx QueryState<'tcx, Q>,
+        state: &'tcx QueryState<'tcx, Self>,
         get_cache: GetCache,
-        key: K,
+        key: Self::Key,
         // `on_hit` can be called while holding a lock to the query state shard.
         on_hit: OnHit,
         on_miss: OnMiss,
     ) -> R
     where
-        Q: QueryAccessors<'tcx>,
-        GetCache: for<'a> Fn(&'a mut QueryStateShard<'tcx, Q>) -> &'a mut Self::Sharded,
-        OnHit: FnOnce(&V, DepNodeIndex) -> R,
-        OnMiss: FnOnce(K, QueryLookup<'tcx, Q>) -> R;
+        GetCache: for<'a> Fn(
+            &'a mut QueryStateShard<'tcx, Self::Key, Self::Sharded>,
+        ) -> &'a mut Self::Sharded,
+        OnHit: FnOnce(&Self::Value, DepNodeIndex) -> R,
+        OnMiss: FnOnce(Self::Key, QueryLookup<'tcx, Self::Key, Self::Sharded>) -> R;
 
     fn complete(
         &self,
         tcx: TyCtxt<'tcx>,
         lock_sharded_storage: &mut Self::Sharded,
-        key: K,
-        value: V,
+        key: Self::Key,
+        value: Self::Value,
         index: DepNodeIndex,
     );
 
@@ -47,36 +50,45 @@ pub(crate) trait QueryCache<K, V>: Default {
         &self,
         shards: &Sharded<L>,
         get_shard: impl Fn(&mut L) -> &mut Self::Sharded,
-        f: impl for<'a> FnOnce(Box<dyn Iterator<Item = (&'a K, &'a V, DepNodeIndex)> + 'a>) -> R,
+        f: impl for<'a> FnOnce(
+            Box<dyn Iterator<Item = (&'a Self::Key, &'a Self::Value, DepNodeIndex)> + 'a>,
+        ) -> R,
     ) -> R;
 }
 
 pub struct DefaultCacheSelector;
 
 impl<K: Eq + Hash, V: Clone> CacheSelector<K, V> for DefaultCacheSelector {
-    type Cache = DefaultCache;
+    type Cache = DefaultCache<K, V>;
 }
 
-#[derive(Default)]
-pub struct DefaultCache;
+pub struct DefaultCache<K, V>(PhantomData<(K, V)>);
+
+impl<K, V> Default for DefaultCache<K, V> {
+    fn default() -> Self {
+        DefaultCache(PhantomData)
+    }
+}
 
-impl<K: Eq + Hash, V: Clone> QueryCache<K, V> for DefaultCache {
+impl<K: Eq + Hash, V: Clone> QueryCache for DefaultCache<K, V> {
+    type Key = K;
+    type Value = V;
     type Sharded = FxHashMap<K, (V, DepNodeIndex)>;
 
     #[inline(always)]
-    fn lookup<'tcx, R, GetCache, OnHit, OnMiss, Q>(
+    fn lookup<'tcx, R, GetCache, OnHit, OnMiss>(
         &self,
-        state: &'tcx QueryState<'tcx, Q>,
+        state: &'tcx QueryState<'tcx, Self>,
         get_cache: GetCache,
         key: K,
         on_hit: OnHit,
         on_miss: OnMiss,
     ) -> R
     where
-        Q: QueryAccessors<'tcx>,
-        GetCache: for<'a> Fn(&'a mut QueryStateShard<'tcx, Q>) -> &'a mut Self::Sharded,
+        GetCache:
+            for<'a> Fn(&'a mut QueryStateShard<'tcx, K, Self::Sharded>) -> &'a mut Self::Sharded,
         OnHit: FnOnce(&V, DepNodeIndex) -> R,
-        OnMiss: FnOnce(K, QueryLookup<'tcx, Q>) -> R,
+        OnMiss: FnOnce(K, QueryLookup<'tcx, K, Self::Sharded>) -> R,
     {
         let mut lookup = state.get_lookup(&key);
         let lock = &mut *lookup.lock;
diff --git a/src/librustc/ty/query/config.rs b/src/librustc/ty/query/config.rs
index 178c2362def6e..72a0fdf156726 100644
--- a/src/librustc/ty/query/config.rs
+++ b/src/librustc/ty/query/config.rs
@@ -2,7 +2,7 @@ use crate::dep_graph::SerializedDepNodeIndex;
 use crate::dep_graph::{DepKind, DepNode};
 use crate::ty::query::caches::QueryCache;
 use crate::ty::query::plumbing::CycleError;
-use crate::ty::query::{Query, QueryState};
+use crate::ty::query::QueryState;
 use crate::ty::TyCtxt;
 use rustc_data_structures::profiling::ProfileCategory;
 use rustc_hir::def_id::DefId;
@@ -28,18 +28,15 @@ pub trait QueryConfig<'tcx> {
 pub(crate) trait QueryAccessors<'tcx>: QueryConfig<'tcx> {
     const ANON: bool;
     const EVAL_ALWAYS: bool;
+    const DEP_KIND: DepKind;
 
-    type Cache: QueryCache<Self::Key, Self::Value>;
-
-    fn query(key: Self::Key) -> Query<'tcx>;
+    type Cache: QueryCache<Key = Self::Key, Value = Self::Value>;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
-    fn query_state<'a>(tcx: TyCtxt<'tcx>) -> &'a QueryState<'tcx, Self>;
+    fn query_state<'a>(tcx: TyCtxt<'tcx>) -> &'a QueryState<'tcx, Self::Cache>;
 
     fn to_dep_node(tcx: TyCtxt<'tcx>, key: &Self::Key) -> DepNode;
 
-    fn dep_kind() -> DepKind;
-
     // Don't use this method to compute query results, instead use the methods on TyCtxt
     fn compute(tcx: TyCtxt<'tcx>, key: Self::Key) -> Self::Value;
 
@@ -62,10 +59,7 @@ pub(crate) trait QueryDescription<'tcx>: QueryAccessors<'tcx> {
     }
 }
 
-impl<'tcx, M: QueryAccessors<'tcx, Key = DefId>> QueryDescription<'tcx> for M
-where
-    <M as QueryAccessors<'tcx>>::Cache: QueryCache<DefId, <M as QueryConfig<'tcx>>::Value>,
-{
+impl<'tcx, M: QueryAccessors<'tcx, Key = DefId>> QueryDescription<'tcx> for M {
     default fn describe(tcx: TyCtxt<'_>, def_id: DefId) -> Cow<'static, str> {
         if !tcx.sess.verbose() {
             format!("processing `{}`", tcx.def_path_str(def_id)).into()
diff --git a/src/librustc/ty/query/mod.rs b/src/librustc/ty/query/mod.rs
index e3859ed12a2eb..ed76951aac5fe 100644
--- a/src/librustc/ty/query/mod.rs
+++ b/src/librustc/ty/query/mod.rs
@@ -57,13 +57,12 @@ use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::collections::BTreeMap;
-use std::convert::TryFrom;
 use std::ops::Deref;
 use std::sync::Arc;
 
 #[macro_use]
 mod plumbing;
-pub use self::plumbing::CycleError;
+pub(crate) use self::plumbing::CycleError;
 use self::plumbing::*;
 
 mod stats;
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index acf67f52dceaa..0bfcae5fa2e66 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -2,10 +2,10 @@
 //! generate the actual methods on tcx which find and execute the provider,
 //! manage the caches, and so forth.
 
-use crate::dep_graph::{DepNode, DepNodeIndex, SerializedDepNodeIndex};
+use crate::dep_graph::{DepKind, DepNode, DepNodeIndex, SerializedDepNodeIndex};
 use crate::ty::query::caches::QueryCache;
-use crate::ty::query::config::{QueryAccessors, QueryDescription};
-use crate::ty::query::job::{QueryInfo, QueryJob, QueryJobId, QueryShardJobId};
+use crate::ty::query::config::QueryDescription;
+use crate::ty::query::job::{QueryInfo, QueryJob, QueryJobId, QueryJobInfo, QueryShardJobId};
 use crate::ty::query::Query;
 use crate::ty::tls;
 use crate::ty::{self, TyCtxt};
@@ -20,6 +20,8 @@ use rustc_errors::{struct_span_err, Diagnostic, DiagnosticBuilder, FatalError, H
 use rustc_span::source_map::DUMMY_SP;
 use rustc_span::Span;
 use std::collections::hash_map::Entry;
+use std::convert::TryFrom;
+use std::fmt::Debug;
 use std::hash::{Hash, Hasher};
 use std::mem;
 use std::num::NonZeroU32;
@@ -27,37 +29,38 @@ use std::ptr;
 #[cfg(debug_assertions)]
 use std::sync::atomic::{AtomicUsize, Ordering};
 
-pub(crate) struct QueryStateShard<'tcx, D: QueryAccessors<'tcx> + ?Sized> {
-    pub(super) cache: <<D as QueryAccessors<'tcx>>::Cache as QueryCache<D::Key, D::Value>>::Sharded,
-    pub(super) active: FxHashMap<D::Key, QueryResult<'tcx>>,
+pub(crate) struct QueryStateShard<'tcx, K, C> {
+    cache: C,
+    active: FxHashMap<K, QueryResult<'tcx>>,
 
     /// Used to generate unique ids for active jobs.
-    pub(super) jobs: u32,
+    jobs: u32,
 }
 
-impl<'tcx, Q: QueryAccessors<'tcx>> QueryStateShard<'tcx, Q> {
-    fn get_cache(
-        &mut self,
-    ) -> &mut <<Q as QueryAccessors<'tcx>>::Cache as QueryCache<Q::Key, Q::Value>>::Sharded {
+impl<'tcx, K, C> QueryStateShard<'tcx, K, C> {
+    fn get_cache(&mut self) -> &mut C {
         &mut self.cache
     }
 }
 
-impl<'tcx, Q: QueryAccessors<'tcx>> Default for QueryStateShard<'tcx, Q> {
-    fn default() -> QueryStateShard<'tcx, Q> {
+impl<'tcx, K, C: Default> Default for QueryStateShard<'tcx, K, C> {
+    fn default() -> QueryStateShard<'tcx, K, C> {
         QueryStateShard { cache: Default::default(), active: Default::default(), jobs: 0 }
     }
 }
 
-pub(crate) struct QueryState<'tcx, D: QueryAccessors<'tcx> + ?Sized> {
-    pub(super) cache: D::Cache,
-    pub(super) shards: Sharded<QueryStateShard<'tcx, D>>,
+pub(crate) struct QueryState<'tcx, C: QueryCache> {
+    cache: C,
+    shards: Sharded<QueryStateShard<'tcx, C::Key, C::Sharded>>,
     #[cfg(debug_assertions)]
     pub(super) cache_hits: AtomicUsize,
 }
 
-impl<'tcx, Q: QueryAccessors<'tcx>> QueryState<'tcx, Q> {
-    pub(super) fn get_lookup<K: Hash>(&'tcx self, key: &K) -> QueryLookup<'tcx, Q> {
+impl<'tcx, C: QueryCache> QueryState<'tcx, C> {
+    pub(super) fn get_lookup<K2: Hash>(
+        &'tcx self,
+        key: &K2,
+    ) -> QueryLookup<'tcx, C::Key, C::Sharded> {
         // We compute the key's hash once and then use it for both the
         // shard lookup and the hashmap lookup. This relies on the fact
         // that both of them use `FxHasher`.
@@ -72,7 +75,7 @@ impl<'tcx, Q: QueryAccessors<'tcx>> QueryState<'tcx, Q> {
 }
 
 /// Indicates the state of a query for a given key in a query map.
-pub(super) enum QueryResult<'tcx> {
+enum QueryResult<'tcx> {
     /// An already executing query. The query job can be used to await for its completion.
     Started(QueryJob<'tcx>),
 
@@ -81,25 +84,54 @@ pub(super) enum QueryResult<'tcx> {
     Poisoned,
 }
 
-impl<'tcx, M: QueryAccessors<'tcx>> QueryState<'tcx, M> {
-    pub fn iter_results<R>(
+impl<'tcx, C: QueryCache> QueryState<'tcx, C> {
+    pub(super) fn iter_results<R>(
         &self,
         f: impl for<'a> FnOnce(
-            Box<dyn Iterator<Item = (&'a M::Key, &'a M::Value, DepNodeIndex)> + 'a>,
+            Box<dyn Iterator<Item = (&'a C::Key, &'a C::Value, DepNodeIndex)> + 'a>,
         ) -> R,
     ) -> R {
         self.cache.iter(&self.shards, |shard| &mut shard.cache, f)
     }
-    pub fn all_inactive(&self) -> bool {
+    pub(super) fn all_inactive(&self) -> bool {
         let shards = self.shards.lock_shards();
         shards.iter().all(|shard| shard.active.is_empty())
     }
+
+    pub(super) fn try_collect_active_jobs(
+        &self,
+        kind: DepKind,
+        make_query: fn(C::Key) -> Query<'tcx>,
+        jobs: &mut FxHashMap<QueryJobId, QueryJobInfo<'tcx>>,
+    ) -> Option<()>
+    where
+        C::Key: Clone,
+    {
+        // We use try_lock_shards here since we are called from the
+        // deadlock handler, and this shouldn't be locked.
+        let shards = self.shards.try_lock_shards()?;
+        let shards = shards.iter().enumerate();
+        jobs.extend(shards.flat_map(|(shard_id, shard)| {
+            shard.active.iter().filter_map(move |(k, v)| {
+                if let QueryResult::Started(ref job) = *v {
+                    let id =
+                        QueryJobId { job: job.id, shard: u16::try_from(shard_id).unwrap(), kind };
+                    let info = QueryInfo { span: job.span, query: make_query(k.clone()) };
+                    Some((id, QueryJobInfo { info, job: job.clone() }))
+                } else {
+                    None
+                }
+            })
+        }));
+
+        Some(())
+    }
 }
 
-impl<'tcx, M: QueryAccessors<'tcx>> Default for QueryState<'tcx, M> {
-    fn default() -> QueryState<'tcx, M> {
+impl<'tcx, C: QueryCache> Default for QueryState<'tcx, C> {
+    fn default() -> QueryState<'tcx, C> {
         QueryState {
-            cache: M::Cache::default(),
+            cache: C::default(),
             shards: Default::default(),
             #[cfg(debug_assertions)]
             cache_hits: AtomicUsize::new(0),
@@ -108,21 +140,31 @@ impl<'tcx, M: QueryAccessors<'tcx>> Default for QueryState<'tcx, M> {
 }
 
 /// Values used when checking a query cache which can be reused on a cache-miss to execute the query.
-pub(crate) struct QueryLookup<'tcx, Q: QueryAccessors<'tcx>> {
+pub(crate) struct QueryLookup<'tcx, K, C> {
     pub(super) key_hash: u64,
-    pub(super) shard: usize,
-    pub(super) lock: LockGuard<'tcx, QueryStateShard<'tcx, Q>>,
+    shard: usize,
+    pub(super) lock: LockGuard<'tcx, QueryStateShard<'tcx, K, C>>,
 }
 
 /// A type representing the responsibility to execute the job in the `job` field.
 /// This will poison the relevant query if dropped.
-pub(super) struct JobOwner<'tcx, Q: QueryDescription<'tcx>> {
-    tcx: TyCtxt<'tcx>,
-    key: Q::Key,
+struct JobOwner<'tcx, C>
+where
+    C: QueryCache,
+    C::Key: Eq + Hash + Clone + Debug,
+    C::Value: Clone,
+{
+    state: &'tcx QueryState<'tcx, C>,
+    key: C::Key,
     id: QueryJobId,
 }
 
-impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
+impl<'tcx, C: QueryCache> JobOwner<'tcx, C>
+where
+    C: QueryCache,
+    C::Key: Eq + Hash + Clone + Debug,
+    C::Value: Clone,
+{
     /// Either gets a `JobOwner` corresponding the query, allowing us to
     /// start executing the query, or returns with the result of the query.
     /// This function assumes that `try_get_cached` is already called and returned `lookup`.
@@ -132,12 +174,15 @@ impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
     /// This function is inlined because that results in a noticeable speed-up
     /// for some compile-time benchmarks.
     #[inline(always)]
-    pub(super) fn try_start(
+    fn try_start<Q>(
         tcx: TyCtxt<'tcx>,
         span: Span,
-        key: &Q::Key,
-        mut lookup: QueryLookup<'tcx, Q>,
-    ) -> TryGetJob<'tcx, Q> {
+        key: &C::Key,
+        mut lookup: QueryLookup<'tcx, C::Key, C::Sharded>,
+    ) -> TryGetJob<'tcx, C>
+    where
+        Q: QueryDescription<'tcx, Key = C::Key, Value = C::Value, Cache = C>,
+    {
         let lock = &mut *lookup.lock;
 
         let (latch, mut _query_blocked_prof_timer) = match lock.active.entry((*key).clone()) {
@@ -154,7 +199,7 @@ impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
                         };
 
                         // Create the id of the job we're waiting for
-                        let id = QueryJobId::new(job.id, lookup.shard, Q::dep_kind());
+                        let id = QueryJobId::new(job.id, lookup.shard, Q::DEP_KIND);
 
                         (job.latch(id), _query_blocked_prof_timer)
                     }
@@ -169,13 +214,14 @@ impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
                 lock.jobs = id;
                 let id = QueryShardJobId(NonZeroU32::new(id).unwrap());
 
-                let global_id = QueryJobId::new(id, lookup.shard, Q::dep_kind());
+                let global_id = QueryJobId::new(id, lookup.shard, Q::DEP_KIND);
 
                 let job = tls::with_related_context(tcx, |icx| QueryJob::new(id, span, icx.query));
 
                 entry.insert(QueryResult::Started(job));
 
-                let owner = JobOwner { tcx, id: global_id, key: (*key).clone() };
+                let owner =
+                    JobOwner { state: Q::query_state(tcx), id: global_id, key: (*key).clone() };
                 return TryGetJob::NotYetStarted(owner);
             }
         };
@@ -198,7 +244,8 @@ impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
                 return TryGetJob::Cycle(Q::handle_cycle_error(tcx, cycle));
             }
 
-            let cached = tcx.try_get_cached::<Q, _, _, _>(
+            let cached = tcx.try_get_cached(
+                Q::query_state(tcx),
                 (*key).clone(),
                 |value, index| (value.clone(), index),
                 |_, _| panic!("value must be in cache after waiting"),
@@ -215,16 +262,15 @@ impl<'tcx, Q: QueryDescription<'tcx>> JobOwner<'tcx, Q> {
     /// Completes the query by updating the query cache with the `result`,
     /// signals the waiter and forgets the JobOwner, so it won't poison the query
     #[inline(always)]
-    pub(super) fn complete(self, result: &Q::Value, dep_node_index: DepNodeIndex) {
+    fn complete(self, tcx: TyCtxt<'tcx>, result: &C::Value, dep_node_index: DepNodeIndex) {
         // We can move out of `self` here because we `mem::forget` it below
         let key = unsafe { ptr::read(&self.key) };
-        let tcx = self.tcx;
+        let state = self.state;
 
         // Forget ourself so our destructor won't poison the query
         mem::forget(self);
 
         let job = {
-            let state = Q::query_state(tcx);
             let result = result.clone();
             let mut lock = state.shards.get_shard_by_value(&key).lock();
             let job = match lock.active.remove(&key).unwrap() {
@@ -249,12 +295,16 @@ where
     (result, diagnostics.into_inner())
 }
 
-impl<'tcx, Q: QueryDescription<'tcx>> Drop for JobOwner<'tcx, Q> {
+impl<'tcx, C: QueryCache> Drop for JobOwner<'tcx, C>
+where
+    C::Key: Eq + Hash + Clone + Debug,
+    C::Value: Clone,
+{
     #[inline(never)]
     #[cold]
     fn drop(&mut self) {
         // Poison the query so jobs waiting on it panic.
-        let state = Q::query_state(self.tcx);
+        let state = self.state;
         let shard = state.shards.get_shard_by_value(&self.key);
         let job = {
             let mut shard = shard.lock();
@@ -272,25 +322,29 @@ impl<'tcx, Q: QueryDescription<'tcx>> Drop for JobOwner<'tcx, Q> {
 }
 
 #[derive(Clone)]
-pub struct CycleError<'tcx> {
+pub(crate) struct CycleError<'tcx> {
     /// The query and related span that uses the cycle.
     pub(super) usage: Option<(Span, Query<'tcx>)>,
     pub(super) cycle: Vec<QueryInfo<'tcx>>,
 }
 
 /// The result of `try_start`.
-pub(super) enum TryGetJob<'tcx, D: QueryDescription<'tcx>> {
+enum TryGetJob<'tcx, C: QueryCache>
+where
+    C::Key: Eq + Hash + Clone + Debug,
+    C::Value: Clone,
+{
     /// The query is not yet started. Contains a guard to the cache eventually used to start it.
-    NotYetStarted(JobOwner<'tcx, D>),
+    NotYetStarted(JobOwner<'tcx, C>),
 
     /// The query was already completed.
     /// Returns the result of the query and its dep-node index
     /// if it succeeded or a cycle error if it failed.
     #[cfg(parallel_compiler)]
-    JobCompleted((D::Value, DepNodeIndex)),
+    JobCompleted((C::Value, DepNodeIndex)),
 
     /// Trying to execute the query resulted in a cycle.
-    Cycle(D::Value),
+    Cycle(C::Value),
 }
 
 impl<'tcx> TyCtxt<'tcx> {
@@ -298,7 +352,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// new query job while it executes. It returns the diagnostics
     /// captured during execution and the actual result.
     #[inline(always)]
-    pub(super) fn start_query<F, R>(
+    fn start_query<F, R>(
         self,
         token: QueryJobId,
         diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
@@ -419,23 +473,22 @@ impl<'tcx> TyCtxt<'tcx> {
     /// which will be used if the query is not in the cache and we need
     /// to compute it.
     #[inline(always)]
-    fn try_get_cached<Q, R, OnHit, OnMiss>(
+    fn try_get_cached<C, R, OnHit, OnMiss>(
         self,
-        key: Q::Key,
+        state: &'tcx QueryState<'tcx, C>,
+        key: C::Key,
         // `on_hit` can be called while holding a lock to the query cache
         on_hit: OnHit,
         on_miss: OnMiss,
     ) -> R
     where
-        Q: QueryDescription<'tcx> + 'tcx,
-        OnHit: FnOnce(&Q::Value, DepNodeIndex) -> R,
-        OnMiss: FnOnce(Q::Key, QueryLookup<'tcx, Q>) -> R,
+        C: QueryCache,
+        OnHit: FnOnce(&C::Value, DepNodeIndex) -> R,
+        OnMiss: FnOnce(C::Key, QueryLookup<'tcx, C::Key, C::Sharded>) -> R,
     {
-        let state = Q::query_state(self);
-
         state.cache.lookup(
             state,
-            QueryStateShard::<Q>::get_cache,
+            QueryStateShard::<C::Key, C::Sharded>::get_cache,
             key,
             |value, index| {
                 if unlikely!(self.prof.enabled()) {
@@ -459,7 +512,8 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> Q::Value {
         debug!("ty::query::get_query<{}>(key={:?}, span={:?})", Q::NAME, key, span);
 
-        self.try_get_cached::<Q, _, _, _>(
+        self.try_get_cached(
+            Q::query_state(self),
             key,
             |value, index| {
                 self.dep_graph.read_index(index);
@@ -470,13 +524,13 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline(always)]
-    pub(super) fn try_execute_query<Q: QueryDescription<'tcx>>(
+    fn try_execute_query<Q: QueryDescription<'tcx> + 'tcx>(
         self,
         span: Span,
         key: Q::Key,
-        lookup: QueryLookup<'tcx, Q>,
+        lookup: QueryLookup<'tcx, Q::Key, <Q::Cache as QueryCache>::Sharded>,
     ) -> Q::Value {
-        let job = match JobOwner::try_start(self, span, &key, lookup) {
+        let job = match JobOwner::try_start::<Q>(self, span, &key, lookup) {
             TryGetJob::NotYetStarted(job) => job,
             TryGetJob::Cycle(result) => return result,
             #[cfg(parallel_compiler)]
@@ -498,7 +552,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
             let ((result, dep_node_index), diagnostics) = with_diagnostics(|diagnostics| {
                 self.start_query(job.id, diagnostics, |tcx| {
-                    tcx.dep_graph.with_anon_task(Q::dep_kind(), || Q::compute(tcx, key))
+                    tcx.dep_graph.with_anon_task(Q::DEP_KIND, || Q::compute(tcx, key))
                 })
             });
 
@@ -512,7 +566,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     .store_diagnostics_for_anon_node(dep_node_index, diagnostics);
             }
 
-            job.complete(&result, dep_node_index);
+            job.complete(self, &result, dep_node_index);
 
             return result;
         }
@@ -538,7 +592,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 })
             });
             if let Some((result, dep_node_index)) = loaded {
-                job.complete(&result, dep_node_index);
+                job.complete(self, &result, dep_node_index);
                 return result;
             }
         }
@@ -634,10 +688,10 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline(always)]
-    fn force_query_with_job<Q: QueryDescription<'tcx>>(
+    fn force_query_with_job<Q: QueryDescription<'tcx> + 'tcx>(
         self,
         key: Q::Key,
-        job: JobOwner<'tcx, Q>,
+        job: JobOwner<'tcx, Q::Cache>,
         dep_node: DepNode,
     ) -> (Q::Value, DepNodeIndex) {
         // If the following assertion triggers, it can have two reasons:
@@ -680,7 +734,7 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         }
 
-        job.complete(&result, dep_node_index);
+        job.complete(self, &result, dep_node_index);
 
         (result, dep_node_index)
     }
@@ -729,13 +783,14 @@ impl<'tcx> TyCtxt<'tcx> {
         // We may be concurrently trying both execute and force a query.
         // Ensure that only one of them runs the query.
 
-        self.try_get_cached::<Q, _, _, _>(
+        self.try_get_cached(
+            Q::query_state(self),
             key,
             |_, _| {
                 // Cache hit, do nothing
             },
             |key, lookup| {
-                let job = match JobOwner::try_start(self, span, &key, lookup) {
+                let job = match JobOwner::try_start::<Q>(self, span, &key, lookup) {
                     TryGetJob::NotYetStarted(job) => job,
                     TryGetJob::Cycle(_) => return,
                     #[cfg(parallel_compiler)]
@@ -842,55 +897,6 @@ macro_rules! define_queries_inner {
             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
         }
 
-        impl<$tcx> Queries<$tcx> {
-            pub fn new(
-                providers: IndexVec<CrateNum, Providers<$tcx>>,
-                fallback_extern_providers: Providers<$tcx>,
-                on_disk_cache: OnDiskCache<'tcx>,
-            ) -> Self {
-                Queries {
-                    providers,
-                    fallback_extern_providers: Box::new(fallback_extern_providers),
-                    on_disk_cache,
-                    $($name: Default::default()),*
-                }
-            }
-
-            pub fn try_collect_active_jobs(
-                &self
-            ) -> Option<FxHashMap<QueryJobId, QueryJobInfo<'tcx>>> {
-                let mut jobs = FxHashMap::default();
-
-                $(
-                    // We use try_lock_shards here since we are called from the
-                    // deadlock handler, and this shouldn't be locked.
-                    let shards = self.$name.shards.try_lock_shards()?;
-                    let shards = shards.iter().enumerate();
-                    jobs.extend(shards.flat_map(|(shard_id, shard)| {
-                        shard.active.iter().filter_map(move |(k, v)| {
-                        if let QueryResult::Started(ref job) = *v {
-                                let id = QueryJobId {
-                                    job: job.id,
-                                    shard:  u16::try_from(shard_id).unwrap(),
-                                    kind:
-                                        <queries::$name<'tcx> as QueryAccessors<'tcx>>::dep_kind(),
-                                };
-                                let info = QueryInfo {
-                                    span: job.span,
-                                    query: queries::$name::query(k.clone())
-                                };
-                                Some((id, QueryJobInfo { info,  job: job.clone() }))
-                        } else {
-                            None
-                        }
-                        })
-                    }));
-                )*
-
-                Some(jobs)
-            }
-        }
-
         #[allow(nonstandard_style)]
         #[derive(Clone, Debug)]
         pub enum Query<$tcx> {
@@ -951,16 +957,6 @@ macro_rules! define_queries_inner {
             })*
         }
 
-        // This module and the functions in it exist only to provide a
-        // predictable symbol name prefix for query providers. This is helpful
-        // for analyzing queries in profilers.
-        pub(super) mod __query_compute {
-            $(#[inline(never)]
-            pub fn $name<F: FnOnce() -> R, R>(f: F) -> R {
-                f()
-            })*
-        }
-
         $(impl<$tcx> QueryConfig<$tcx> for queries::$name<$tcx> {
             type Key = $K;
             type Value = $V;
@@ -971,16 +967,12 @@ macro_rules! define_queries_inner {
         impl<$tcx> QueryAccessors<$tcx> for queries::$name<$tcx> {
             const ANON: bool = is_anon!([$($modifiers)*]);
             const EVAL_ALWAYS: bool = is_eval_always!([$($modifiers)*]);
+            const DEP_KIND: dep_graph::DepKind = dep_graph::DepKind::$node;
 
             type Cache = query_storage!([$($modifiers)*][$K, $V]);
 
             #[inline(always)]
-            fn query(key: Self::Key) -> Query<'tcx> {
-                Query::$name(key)
-            }
-
-            #[inline(always)]
-            fn query_state<'a>(tcx: TyCtxt<$tcx>) -> &'a QueryState<$tcx, Self> {
+            fn query_state<'a>(tcx: TyCtxt<$tcx>) -> &'a QueryState<$tcx, Self::Cache> {
                 &tcx.queries.$name
             }
 
@@ -990,23 +982,16 @@ macro_rules! define_queries_inner {
                 DepConstructor::$node(tcx, *key)
             }
 
-            #[inline(always)]
-            fn dep_kind() -> dep_graph::DepKind {
-                dep_graph::DepKind::$node
-            }
-
             #[inline]
             fn compute(tcx: TyCtxt<'tcx>, key: Self::Key) -> Self::Value {
-                __query_compute::$name(move || {
-                    let provider = tcx.queries.providers.get(key.query_crate())
-                        // HACK(eddyb) it's possible crates may be loaded after
-                        // the query engine is created, and because crate loading
-                        // is not yet integrated with the query engine, such crates
-                        // would be missing appropriate entries in `providers`.
-                        .unwrap_or(&tcx.queries.fallback_extern_providers)
-                        .$name;
-                    provider(tcx, key)
-                })
+                let provider = tcx.queries.providers.get(key.query_crate())
+                    // HACK(eddyb) it's possible crates may be loaded after
+                    // the query engine is created, and because crate loading
+                    // is not yet integrated with the query engine, such crates
+                    // would be missing appropriate entries in `providers`.
+                    .unwrap_or(&tcx.queries.fallback_extern_providers)
+                    .$name;
+                provider(tcx, key)
             }
 
             fn hash_result(
@@ -1139,7 +1124,41 @@ macro_rules! define_queries_struct {
             providers: IndexVec<CrateNum, Providers<$tcx>>,
             fallback_extern_providers: Box<Providers<$tcx>>,
 
-            $($(#[$attr])*  $name: QueryState<$tcx, queries::$name<$tcx>>,)*
+            $($(#[$attr])*  $name: QueryState<
+                $tcx,
+                <queries::$name<$tcx> as QueryAccessors<'tcx>>::Cache,
+            >,)*
+        }
+
+        impl<$tcx> Queries<$tcx> {
+            pub(crate) fn new(
+                providers: IndexVec<CrateNum, Providers<$tcx>>,
+                fallback_extern_providers: Providers<$tcx>,
+                on_disk_cache: OnDiskCache<'tcx>,
+            ) -> Self {
+                Queries {
+                    providers,
+                    fallback_extern_providers: Box::new(fallback_extern_providers),
+                    on_disk_cache,
+                    $($name: Default::default()),*
+                }
+            }
+
+            pub(crate) fn try_collect_active_jobs(
+                &self
+            ) -> Option<FxHashMap<QueryJobId, QueryJobInfo<'tcx>>> {
+                let mut jobs = FxHashMap::default();
+
+                $(
+                    self.$name.try_collect_active_jobs(
+                        <queries::$name<'tcx> as QueryAccessors<'tcx>>::DEP_KIND,
+                        Query::$name,
+                        &mut jobs,
+                    )?;
+                )*
+
+                Some(jobs)
+            }
         }
     };
 }
diff --git a/src/librustc/ty/query/profiling_support.rs b/src/librustc/ty/query/profiling_support.rs
index 99ada34d59ebe..58ace917786cf 100644
--- a/src/librustc/ty/query/profiling_support.rs
+++ b/src/librustc/ty/query/profiling_support.rs
@@ -1,6 +1,6 @@
 use crate::hir::map::definitions::DefPathData;
 use crate::ty::context::TyCtxt;
-use crate::ty::query::config::QueryAccessors;
+use crate::ty::query::caches::QueryCache;
 use crate::ty::query::plumbing::QueryState;
 use measureme::{StringComponent, StringId};
 use rustc_data_structures::fx::FxHashMap;
@@ -157,13 +157,14 @@ where
 /// Allocate the self-profiling query strings for a single query cache. This
 /// method is called from `alloc_self_profile_query_strings` which knows all
 /// the queries via macro magic.
-pub(super) fn alloc_self_profile_query_strings_for_query_cache<'tcx, Q>(
+pub(super) fn alloc_self_profile_query_strings_for_query_cache<'tcx, C>(
     tcx: TyCtxt<'tcx>,
     query_name: &'static str,
-    query_state: &QueryState<'tcx, Q>,
+    query_state: &QueryState<'tcx, C>,
     string_cache: &mut QueryKeyStringCache,
 ) where
-    Q: QueryAccessors<'tcx>,
+    C: QueryCache,
+    C::Key: Debug + Clone,
 {
     tcx.prof.with_profiler(|profiler| {
         let event_id_builder = profiler.event_id_builder();
diff --git a/src/librustc/ty/query/stats.rs b/src/librustc/ty/query/stats.rs
index d257320d4eaf6..527bb46c90888 100644
--- a/src/librustc/ty/query/stats.rs
+++ b/src/librustc/ty/query/stats.rs
@@ -1,3 +1,4 @@
+use crate::ty::query::caches::QueryCache;
 use crate::ty::query::config::QueryAccessors;
 use crate::ty::query::plumbing::QueryState;
 use crate::ty::query::queries;
@@ -37,20 +38,17 @@ struct QueryStats {
     local_def_id_keys: Option<usize>,
 }
 
-fn stats<'tcx, Q: QueryAccessors<'tcx>>(
-    name: &'static str,
-    map: &QueryState<'tcx, Q>,
-) -> QueryStats {
+fn stats<'tcx, C: QueryCache>(name: &'static str, map: &QueryState<'tcx, C>) -> QueryStats {
     let mut stats = QueryStats {
         name,
         #[cfg(debug_assertions)]
         cache_hits: map.cache_hits.load(Ordering::Relaxed),
         #[cfg(not(debug_assertions))]
         cache_hits: 0,
-        key_size: mem::size_of::<Q::Key>(),
-        key_type: type_name::<Q::Key>(),
-        value_size: mem::size_of::<Q::Value>(),
-        value_type: type_name::<Q::Value>(),
+        key_size: mem::size_of::<C::Key>(),
+        key_type: type_name::<C::Key>(),
+        value_size: mem::size_of::<C::Value>(),
+        value_type: type_name::<C::Value>(),
         entry_count: map.iter_results(|results| results.count()),
         local_def_id_keys: None,
     };
@@ -125,7 +123,9 @@ macro_rules! print_stats {
             let mut queries = Vec::new();
 
             $($(
-                queries.push(stats::<queries::$name<'_>>(
+                queries.push(stats::<
+                    <queries::$name<'_> as QueryAccessors<'_>>::Cache,
+                >(
                     stringify!($name),
                     &tcx.queries.$name,
                 ));
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 0d063d82c6934..1fb1965484af2 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -71,8 +71,7 @@ pub fn write_compressed_metadata<'tcx>(
         // flags, at least for ELF outputs, so that the
         // metadata doesn't get loaded into memory.
         let directive = format!(".section {}", section_name);
-        let directive = CString::new(directive).unwrap();
-        llvm::LLVMSetModuleInlineAsm(metadata_llmod, directive.as_ptr())
+        llvm::LLVMSetModuleInlineAsm2(metadata_llmod, directive.as_ptr().cast(), directive.len())
     }
 }
 
diff --git a/src/librustc_codegen_llvm/consts.rs b/src/librustc_codegen_llvm/consts.rs
index 09a84aff16811..619dee2909281 100644
--- a/src/librustc_codegen_llvm/consts.rs
+++ b/src/librustc_codegen_llvm/consts.rs
@@ -1,7 +1,7 @@
 use crate::base;
 use crate::common::CodegenCx;
 use crate::debuginfo;
-use crate::llvm::{self, SetUnnamedAddr, True};
+use crate::llvm::{self, True};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
@@ -183,7 +183,7 @@ impl CodegenCx<'ll, 'tcx> {
             };
             llvm::LLVMSetInitializer(gv, cv);
             set_global_alignment(&self, gv, align);
-            SetUnnamedAddr(gv, true);
+            llvm::SetUnnamedAddress(gv, llvm::UnnamedAddr::Global);
             gv
         }
     }
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 7b1526e9da154..c25fcb3d9d1cb 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -166,7 +166,7 @@ pub unsafe fn create_module(
         llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, tm);
         llvm::LLVMRustDisposeTargetMachine(tm);
 
-        let llvm_data_layout = llvm::LLVMGetDataLayout(llmod);
+        let llvm_data_layout = llvm::LLVMGetDataLayoutStr(llmod);
         let llvm_data_layout = str::from_utf8(CStr::from_ptr(llvm_data_layout).to_bytes())
             .expect("got a non-UTF8 data-layout from LLVM");
 
@@ -458,7 +458,7 @@ impl CodegenCx<'b, 'tcx> {
             self.type_variadic_func(&[], ret)
         };
         let f = self.declare_cfn(name, fn_ty);
-        llvm::SetUnnamedAddr(f, false);
+        llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
         self.intrinsics.borrow_mut().insert(name, f);
         f
     }
diff --git a/src/librustc_codegen_llvm/debuginfo/gdb.rs b/src/librustc_codegen_llvm/debuginfo/gdb.rs
index e4cbffb6db3c3..dccd287a2e38c 100644
--- a/src/librustc_codegen_llvm/debuginfo/gdb.rs
+++ b/src/librustc_codegen_llvm/debuginfo/gdb.rs
@@ -50,7 +50,7 @@ pub fn get_or_insert_gdb_debug_scripts_section_global(cx: &CodegenCx<'ll, '_>) -
             llvm::LLVMSetSection(section_var, section_name.as_ptr().cast());
             llvm::LLVMSetInitializer(section_var, cx.const_bytes(section_contents));
             llvm::LLVMSetGlobalConstant(section_var, llvm::True);
-            llvm::LLVMSetUnnamedAddr(section_var, llvm::True);
+            llvm::LLVMSetUnnamedAddress(section_var, llvm::UnnamedAddr::Global);
             llvm::LLVMRustSetLinkage(section_var, llvm::Linkage::LinkOnceODRLinkage);
             // This should make sure that the whole section is not larger than
             // the string it contains. Otherwise we get a warning from GDB.
diff --git a/src/librustc_codegen_llvm/declare.rs b/src/librustc_codegen_llvm/declare.rs
index fab6321186b2c..236f5bb1bfdfb 100644
--- a/src/librustc_codegen_llvm/declare.rs
+++ b/src/librustc_codegen_llvm/declare.rs
@@ -40,7 +40,7 @@ fn declare_raw_fn(
     llvm::SetFunctionCallConv(llfn, callconv);
     // Function addresses in Rust are never significant, allowing functions to
     // be merged.
-    llvm::SetUnnamedAddr(llfn, true);
+    llvm::SetUnnamedAddress(llfn, llvm::UnnamedAddr::Global);
 
     if cx.tcx.sess.opts.cg.no_redzone.unwrap_or(cx.tcx.sess.target.target.options.disable_redzone) {
         llvm::Attribute::NoRedZone.apply_llfn(Function, llfn);
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 1ddfde526fabd..95982c860f3c1 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -1662,7 +1662,7 @@ fn generic_simd_intrinsic(
                 llvm_elem_vec_ty,
             ),
         );
-        llvm::SetUnnamedAddr(f, false);
+        llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
         return Ok(v);
     }
@@ -1784,7 +1784,7 @@ fn generic_simd_intrinsic(
             &llvm_intrinsic,
             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t),
         );
-        llvm::SetUnnamedAddr(f, false);
+        llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
         return Ok(v);
     }
@@ -2083,7 +2083,7 @@ unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
 
         let f = bx.declare_cfn(&llvm_intrinsic, bx.type_func(&[vec_ty, vec_ty], vec_ty));
-        llvm::SetUnnamedAddr(f, false);
+        llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
         let v = bx.call(f, &[lhs, rhs], None);
         return Ok(v);
     }
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index c17c06718f506..69881e2149bc4 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -73,6 +73,14 @@ pub enum Visibility {
     Protected = 2,
 }
 
+/// LLVMUnnamedAddr
+#[repr(C)]
+pub enum UnnamedAddr {
+    No,
+    Local,
+    Global,
+}
+
 /// LLVMDLLStorageClass
 #[derive(Copy, Clone)]
 #[repr(C)]
@@ -727,11 +735,11 @@ extern "C" {
     pub fn LLVMCloneModule(M: &Module) -> &Module;
 
     /// Data layout. See Module::getDataLayout.
-    pub fn LLVMGetDataLayout(M: &Module) -> *const c_char;
+    pub fn LLVMGetDataLayoutStr(M: &Module) -> *const c_char;
     pub fn LLVMSetDataLayout(M: &Module, Triple: *const c_char);
 
     /// See Module::setModuleInlineAsm.
-    pub fn LLVMSetModuleInlineAsm(M: &Module, Asm: *const c_char);
+    pub fn LLVMSetModuleInlineAsm2(M: &Module, Asm: *const c_char, AsmLen: size_t);
     pub fn LLVMRustAppendModuleInlineAsm(M: &Module, Asm: *const c_char, AsmLen: size_t);
 
     /// See llvm::LLVMTypeKind::getTypeID.
@@ -1853,7 +1861,7 @@ extern "C" {
         UniqueIdLen: size_t,
     ) -> &'a DIDerivedType;
 
-    pub fn LLVMSetUnnamedAddr(GlobalVar: &Value, UnnamedAddr: Bool);
+    pub fn LLVMSetUnnamedAddress(Global: &Value, UnnamedAddr: UnnamedAddr);
 
     pub fn LLVMRustDIBuilderCreateTemplateTypeParameter(
         Builder: &DIBuilder<'a>,
diff --git a/src/librustc_codegen_llvm/llvm/mod.rs b/src/librustc_codegen_llvm/llvm/mod.rs
index a083e14979c0b..b7f1e1789c9e2 100644
--- a/src/librustc_codegen_llvm/llvm/mod.rs
+++ b/src/librustc_codegen_llvm/llvm/mod.rs
@@ -106,9 +106,9 @@ pub fn UnsetComdat(val: &'a Value) {
     }
 }
 
-pub fn SetUnnamedAddr(global: &'a Value, unnamed: bool) {
+pub fn SetUnnamedAddress(global: &'a Value, unnamed: UnnamedAddr) {
     unsafe {
-        LLVMSetUnnamedAddr(global, unnamed as Bool);
+        LLVMSetUnnamedAddress(global, unnamed);
     }
 }
 
diff --git a/src/librustc_codegen_ssa/mir/mod.rs b/src/librustc_codegen_ssa/mir/mod.rs
index 64ead19b35869..000db0155ada3 100644
--- a/src/librustc_codegen_ssa/mir/mod.rs
+++ b/src/librustc_codegen_ssa/mir/mod.rs
@@ -86,13 +86,18 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn monomorphize<T>(&self, value: &T) -> T
     where
-        T: TypeFoldable<'tcx>,
+        T: Copy + TypeFoldable<'tcx>,
     {
-        self.cx.tcx().subst_and_normalize_erasing_regions(
-            self.instance.substs,
-            ty::ParamEnv::reveal_all(),
-            value,
-        )
+        debug!("monomorphize: self.instance={:?}", self.instance);
+        if let Some(substs) = self.instance.substs_for_mir_body() {
+            self.cx.tcx().subst_and_normalize_erasing_regions(
+                substs,
+                ty::ParamEnv::reveal_all(),
+                &value,
+            )
+        } else {
+            self.cx.tcx().normalize_erasing_regions(ty::ParamEnv::reveal_all(), *value)
+        }
     }
 }
 
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 481719bfa8e63..68a893dc4be5d 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -335,15 +335,25 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
     /// Call this on things you got out of the MIR (so it is as generic as the current
     /// stack frame), to bring it into the proper environment for this interpreter.
+    pub(super) fn subst_from_current_frame_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
+        &self,
+        value: T,
+    ) -> T {
+        self.subst_from_frame_and_normalize_erasing_regions(self.frame(), value)
+    }
+
+    /// Call this on things you got out of the MIR (so it is as generic as the provided
+    /// stack frame), to bring it into the proper environment for this interpreter.
     pub(super) fn subst_from_frame_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
         &self,
+        frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
         value: T,
     ) -> T {
-        self.tcx.subst_and_normalize_erasing_regions(
-            self.frame().instance.substs,
-            self.param_env,
-            &value,
-        )
+        if let Some(substs) = frame.instance.substs_for_mir_body() {
+            self.tcx.subst_and_normalize_erasing_regions(substs, self.param_env, &value)
+        } else {
+            self.tcx.normalize_erasing_regions(self.param_env, value)
+        }
     }
 
     /// The `substs` are assumed to already be in our interpreter "universe" (param_env).
@@ -371,11 +381,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             None => {
                 let layout = crate::interpret::operand::from_known_layout(layout, || {
                     let local_ty = frame.body.local_decls[local].ty;
-                    let local_ty = self.tcx.subst_and_normalize_erasing_regions(
-                        frame.instance.substs,
-                        self.param_env,
-                        &local_ty,
-                    );
+                    let local_ty =
+                        self.subst_from_frame_and_normalize_erasing_regions(frame, local_ty);
                     self.layout_of(local_ty)
                 })?;
                 if let Some(state) = frame.locals.get(local) {
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 316cf2ee41918..b39058405f5cb 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -355,7 +355,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
         let base = match op.try_as_mplace(self) {
             Ok(mplace) => {
-                // The easy case
+                // We can reuse the mplace field computation logic for indirect operands.
                 let field = self.mplace_field(mplace, field)?;
                 return Ok(field.into());
             }
@@ -490,7 +490,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             Copy(ref place) | Move(ref place) => self.eval_place_to_op(place, layout)?,
 
             Constant(ref constant) => {
-                let val = self.subst_from_frame_and_normalize_erasing_regions(constant.literal);
+                let val =
+                    self.subst_from_current_frame_and_normalize_erasing_regions(constant.literal);
                 self.eval_const_to_op(val, layout)?
             }
         };
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 107cfee5aceb5..5313446c253c8 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -410,14 +410,6 @@ where
                 stride * field
             }
             layout::FieldPlacement::Union(count) => {
-                // This is a narrow bug-fix for rust-lang/rust#69191: if we are
-                // trying to access absent field of uninhabited variant, then
-                // signal UB (but don't ICE the compiler).
-                // FIXME temporary hack to work around incoherence between
-                // layout computation and MIR building
-                if field >= count as u64 && base.layout.abi == layout::Abi::Uninhabited {
-                    throw_ub!(Unreachable);
-                }
                 assert!(
                     field < count as u64,
                     "Tried to access field {} of union {:#?} with {} fields",
@@ -648,9 +640,11 @@ where
                         // bail out.
                         None => Place::null(&*self),
                     },
-                    layout: self.layout_of(self.subst_from_frame_and_normalize_erasing_regions(
-                        self.frame().body.return_ty(),
-                    ))?,
+                    layout: self.layout_of(
+                        self.subst_from_current_frame_and_normalize_erasing_regions(
+                            self.frame().body.return_ty(),
+                        ),
+                    )?,
                 }
             }
             local => PlaceTy {
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index f298a6677d6dc..cb11df18378d9 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -248,7 +248,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
 
             NullaryOp(mir::NullOp::SizeOf, ty) => {
-                let ty = self.subst_from_frame_and_normalize_erasing_regions(ty);
+                let ty = self.subst_from_current_frame_and_normalize_erasing_regions(ty);
                 let layout = self.layout_of(ty)?;
                 assert!(
                     !layout.is_unsized(),
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index 51760500b03c9..4dd037d93ce9b 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -185,7 +185,7 @@ use rustc::mir::visit::Visitor as MirVisitor;
 use rustc::mir::{self, Local, Location};
 use rustc::ty::adjustment::{CustomCoerceUnsized, PointerCast};
 use rustc::ty::print::obsolete::DefPathBasedNames;
-use rustc::ty::subst::{InternalSubsts, SubstsRef};
+use rustc::ty::subst::InternalSubsts;
 use rustc::ty::{self, GenericParamDefKind, Instance, Ty, TyCtxt, TypeFoldable};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::{par_iter, MTLock, MTRef, ParallelIterator};
@@ -493,7 +493,21 @@ struct MirNeighborCollector<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     body: &'a mir::Body<'tcx>,
     output: &'a mut Vec<MonoItem<'tcx>>,
-    param_substs: SubstsRef<'tcx>,
+    instance: Instance<'tcx>,
+}
+
+impl<'a, 'tcx> MirNeighborCollector<'a, 'tcx> {
+    pub fn monomorphize<T>(&self, value: T) -> T
+    where
+        T: TypeFoldable<'tcx>,
+    {
+        debug!("monomorphize: self.instance={:?}", self.instance);
+        if let Some(substs) = self.instance.substs_for_mir_body() {
+            self.tcx.subst_and_normalize_erasing_regions(substs, ty::ParamEnv::reveal_all(), &value)
+        } else {
+            self.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), value)
+        }
+    }
 }
 
 impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
@@ -509,17 +523,9 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 ref operand,
                 target_ty,
             ) => {
-                let target_ty = self.tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &target_ty,
-                );
+                let target_ty = self.monomorphize(target_ty);
                 let source_ty = operand.ty(self.body, self.tcx);
-                let source_ty = self.tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &source_ty,
-                );
+                let source_ty = self.monomorphize(source_ty);
                 let (source_ty, target_ty) =
                     find_vtable_types_for_unsizing(self.tcx, source_ty, target_ty);
                 // This could also be a different Unsize instruction, like
@@ -540,11 +546,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 _,
             ) => {
                 let fn_ty = operand.ty(self.body, self.tcx);
-                let fn_ty = self.tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &fn_ty,
-                );
+                let fn_ty = self.monomorphize(fn_ty);
                 visit_fn_use(self.tcx, fn_ty, false, &mut self.output);
             }
             mir::Rvalue::Cast(
@@ -553,11 +555,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 _,
             ) => {
                 let source_ty = operand.ty(self.body, self.tcx);
-                let source_ty = self.tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &source_ty,
-                );
+                let source_ty = self.monomorphize(source_ty);
                 match source_ty.kind {
                     ty::Closure(def_id, substs) => {
                         let instance = Instance::resolve_closure(
@@ -593,7 +591,23 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
     fn visit_const(&mut self, constant: &&'tcx ty::Const<'tcx>, location: Location) {
         debug!("visiting const {:?} @ {:?}", *constant, location);
 
-        collect_const(self.tcx, *constant, self.param_substs, self.output);
+        let substituted_constant = self.monomorphize(*constant);
+        let param_env = ty::ParamEnv::reveal_all();
+
+        match substituted_constant.val {
+            ty::ConstKind::Value(val) => collect_const_value(self.tcx, val, self.output),
+            ty::ConstKind::Unevaluated(def_id, substs, promoted) => {
+                match self.tcx.const_eval_resolve(param_env, def_id, substs, promoted, None) {
+                    Ok(val) => collect_const_value(self.tcx, val, self.output),
+                    Err(ErrorHandled::Reported) => {}
+                    Err(ErrorHandled::TooGeneric) => span_bug!(
+                        self.tcx.def_span(def_id),
+                        "collection encountered polymorphic constant",
+                    ),
+                }
+            }
+            _ => {}
+        }
 
         self.super_const(constant);
     }
@@ -605,21 +619,13 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
         match *kind {
             mir::TerminatorKind::Call { ref func, .. } => {
                 let callee_ty = func.ty(self.body, tcx);
-                let callee_ty = tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &callee_ty,
-                );
+                let callee_ty = self.monomorphize(callee_ty);
                 visit_fn_use(self.tcx, callee_ty, true, &mut self.output);
             }
             mir::TerminatorKind::Drop { ref location, .. }
             | mir::TerminatorKind::DropAndReplace { ref location, .. } => {
                 let ty = location.ty(self.body, self.tcx).ty;
-                let ty = tcx.subst_and_normalize_erasing_regions(
-                    self.param_substs,
-                    ty::ParamEnv::reveal_all(),
-                    &ty,
-                );
+                let ty = self.monomorphize(ty);
                 visit_drop_use(self.tcx, ty, true, self.output);
             }
             mir::TerminatorKind::Goto { .. }
@@ -1156,8 +1162,7 @@ fn collect_neighbours<'tcx>(
     debug!("collect_neighbours: {:?}", instance.def_id());
     let body = tcx.instance_mir(instance.def);
 
-    MirNeighborCollector { tcx, body: &body, output, param_substs: instance.substs }
-        .visit_body(body);
+    MirNeighborCollector { tcx, body: &body, output, instance }.visit_body(body);
 }
 
 fn def_id_to_string(tcx: TyCtxt<'_>, def_id: DefId) -> String {
@@ -1167,33 +1172,6 @@ fn def_id_to_string(tcx: TyCtxt<'_>, def_id: DefId) -> String {
     output
 }
 
-fn collect_const<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    constant: &'tcx ty::Const<'tcx>,
-    param_substs: SubstsRef<'tcx>,
-    output: &mut Vec<MonoItem<'tcx>>,
-) {
-    debug!("visiting const {:?}", constant);
-
-    let param_env = ty::ParamEnv::reveal_all();
-    let substituted_constant =
-        tcx.subst_and_normalize_erasing_regions(param_substs, param_env, &constant);
-
-    match substituted_constant.val {
-        ty::ConstKind::Value(val) => collect_const_value(tcx, val, output),
-        ty::ConstKind::Unevaluated(def_id, substs, promoted) => {
-            match tcx.const_eval_resolve(param_env, def_id, substs, promoted, None) {
-                Ok(val) => collect_const_value(tcx, val, output),
-                Err(ErrorHandled::Reported) => {}
-                Err(ErrorHandled::TooGeneric) => {
-                    span_bug!(tcx.def_span(def_id), "collection encountered polymorphic constant",)
-                }
-            }
-        }
-        _ => {}
-    }
-}
-
 fn collect_const_value<'tcx>(
     tcx: TyCtxt<'tcx>,
     value: ConstValue<'tcx>,
diff --git a/src/librustc_target/abi/mod.rs b/src/librustc_target/abi/mod.rs
index 2f8bbd66c322b..afa30e7e632a7 100644
--- a/src/librustc_target/abi/mod.rs
+++ b/src/librustc_target/abi/mod.rs
@@ -660,7 +660,10 @@ impl FieldPlacement {
 
     pub fn offset(&self, i: usize) -> Size {
         match *self {
-            FieldPlacement::Union(_) => Size::ZERO,
+            FieldPlacement::Union(count) => {
+                assert!(i < count, "tried to access field {} of union with {} fields", i, count);
+                Size::ZERO
+            }
             FieldPlacement::Array { stride, count } => {
                 let i = i as u64;
                 assert!(i < count);
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 0fb0757792ed7..9a82ae7626d97 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -6,7 +6,7 @@ use crate::cell::RefCell;
 use crate::fmt;
 use crate::io::lazy::Lazy;
 use crate::io::{self, BufReader, Initializer, IoSlice, IoSliceMut, LineWriter};
-use crate::sync::{Arc, Mutex, MutexGuard};
+use crate::sync::{Arc, Mutex, MutexGuard, Once};
 use crate::sys::stdio;
 use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
 use crate::thread::LocalKey;
@@ -493,7 +493,11 @@ pub fn stdout() -> Stdout {
             Ok(stdout) => Maybe::Real(stdout),
             _ => Maybe::Fake,
         };
-        Arc::new(ReentrantMutex::new(RefCell::new(LineWriter::new(stdout))))
+        unsafe {
+            let ret = Arc::new(ReentrantMutex::new(RefCell::new(LineWriter::new(stdout))));
+            ret.init();
+            return ret;
+        }
     }
 }
 
@@ -520,7 +524,7 @@ impl Stdout {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn lock(&self) -> StdoutLock<'_> {
-        StdoutLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) }
+        StdoutLock { inner: self.inner.lock() }
     }
 }
 
@@ -581,7 +585,7 @@ impl fmt::Debug for StdoutLock<'_> {
 /// an error.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Stderr {
-    inner: Arc<ReentrantMutex<RefCell<Maybe<StderrRaw>>>>,
+    inner: &'static ReentrantMutex<RefCell<Maybe<StderrRaw>>>,
 }
 
 /// A locked reference to the `Stderr` handle.
@@ -639,19 +643,28 @@ pub struct StderrLock<'a> {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stderr() -> Stderr {
-    static INSTANCE: Lazy<ReentrantMutex<RefCell<Maybe<StderrRaw>>>> = Lazy::new();
-    return Stderr {
-        inner: unsafe { INSTANCE.get(stderr_init).expect("cannot access stderr during shutdown") },
-    };
-
-    fn stderr_init() -> Arc<ReentrantMutex<RefCell<Maybe<StderrRaw>>>> {
-        // This must not reentrantly access `INSTANCE`
-        let stderr = match stderr_raw() {
-            Ok(stderr) => Maybe::Real(stderr),
-            _ => Maybe::Fake,
-        };
-        Arc::new(ReentrantMutex::new(RefCell::new(stderr)))
-    }
+    // Note that unlike `stdout()` we don't use `Lazy` here which registers a
+    // destructor. Stderr is not buffered nor does the `stderr_raw` type consume
+    // any owned resources, so there's no need to run any destructors at some
+    // point in the future.
+    //
+    // This has the added benefit of allowing `stderr` to be usable during
+    // process shutdown as well!
+    static INSTANCE: ReentrantMutex<RefCell<Maybe<StderrRaw>>> =
+        unsafe { ReentrantMutex::new(RefCell::new(Maybe::Fake)) };
+
+    // When accessing stderr we need one-time initialization of the reentrant
+    // mutex, followed by one-time detection of whether we actually have a
+    // stderr handle or not. Afterwards we can just always use the now-filled-in
+    // `INSTANCE` value.
+    static INIT: Once = Once::new();
+    INIT.call_once(|| unsafe {
+        INSTANCE.init();
+        if let Ok(stderr) = stderr_raw() {
+            *INSTANCE.lock().borrow_mut() = Maybe::Real(stderr);
+        }
+    });
+    return Stderr { inner: &INSTANCE };
 }
 
 impl Stderr {
@@ -677,7 +690,7 @@ impl Stderr {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn lock(&self) -> StderrLock<'_> {
-        StderrLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) }
+        StderrLock { inner: self.inner.lock() }
     }
 }
 
diff --git a/src/libstd/sys/cloudabi/mutex.rs b/src/libstd/sys/cloudabi/mutex.rs
index 4aa25e2505271..580ab0e8ad863 100644
--- a/src/libstd/sys/cloudabi/mutex.rs
+++ b/src/libstd/sys/cloudabi/mutex.rs
@@ -53,16 +53,16 @@ pub struct ReentrantMutex {
 }
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex {
             lock: UnsafeCell::new(MaybeUninit::uninit()),
             recursion: UnsafeCell::new(MaybeUninit::uninit()),
         }
     }
 
-    pub unsafe fn init(&mut self) {
-        self.lock = UnsafeCell::new(MaybeUninit::new(AtomicU32::new(abi::LOCK_UNLOCKED.0)));
-        self.recursion = UnsafeCell::new(MaybeUninit::new(0));
+    pub unsafe fn init(&self) {
+        *self.lock.get() = MaybeUninit::new(AtomicU32::new(abi::LOCK_UNLOCKED.0));
+        *self.recursion.get() = MaybeUninit::new(0);
     }
 
     pub unsafe fn try_lock(&self) -> bool {
diff --git a/src/libstd/sys/hermit/mutex.rs b/src/libstd/sys/hermit/mutex.rs
index b5c75f738d228..3d4813209cbc4 100644
--- a/src/libstd/sys/hermit/mutex.rs
+++ b/src/libstd/sys/hermit/mutex.rs
@@ -46,13 +46,13 @@ pub struct ReentrantMutex {
 }
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: ptr::null() }
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {
-        let _ = abi::recmutex_init(&mut self.inner as *mut *const c_void);
+    pub unsafe fn init(&self) {
+        let _ = abi::recmutex_init(&self.inner as *const *const c_void as *mut _);
     }
 
     #[inline]
diff --git a/src/libstd/sys/sgx/mutex.rs b/src/libstd/sys/sgx/mutex.rs
index eebbea1b285ba..4911c2f538769 100644
--- a/src/libstd/sys/sgx/mutex.rs
+++ b/src/libstd/sys/sgx/mutex.rs
@@ -75,7 +75,7 @@ impl ReentrantMutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
+    pub unsafe fn init(&self) {}
 
     #[inline]
     pub unsafe fn lock(&self) {
diff --git a/src/libstd/sys/unix/mutex.rs b/src/libstd/sys/unix/mutex.rs
index b38375a2e03c5..103d87e3d2f91 100644
--- a/src/libstd/sys/unix/mutex.rs
+++ b/src/libstd/sys/unix/mutex.rs
@@ -92,11 +92,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
         let result = libc::pthread_mutexattr_init(attr.as_mut_ptr());
         debug_assert_eq!(result, 0);
diff --git a/src/libstd/sys/vxworks/mutex.rs b/src/libstd/sys/vxworks/mutex.rs
index b38375a2e03c5..103d87e3d2f91 100644
--- a/src/libstd/sys/vxworks/mutex.rs
+++ b/src/libstd/sys/vxworks/mutex.rs
@@ -92,11 +92,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
         let result = libc::pthread_mutexattr_init(attr.as_mut_ptr());
         debug_assert_eq!(result, 0);
diff --git a/src/libstd/sys/wasm/mutex.rs b/src/libstd/sys/wasm/mutex.rs
index 07238d087308f..7aaf1b3a343b6 100644
--- a/src/libstd/sys/wasm/mutex.rs
+++ b/src/libstd/sys/wasm/mutex.rs
@@ -47,11 +47,11 @@ impl Mutex {
 pub struct ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex {}
     }
 
-    pub unsafe fn init(&mut self) {}
+    pub unsafe fn init(&self) {}
 
     pub unsafe fn lock(&self) {}
 
diff --git a/src/libstd/sys/wasm/mutex_atomics.rs b/src/libstd/sys/wasm/mutex_atomics.rs
index 90c628a19c22e..268a53bb5641c 100644
--- a/src/libstd/sys/wasm/mutex_atomics.rs
+++ b/src/libstd/sys/wasm/mutex_atomics.rs
@@ -80,11 +80,11 @@ unsafe impl Sync for ReentrantMutex {}
 // released when this recursion counter reaches 0.
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { owner: AtomicU32::new(0), recursions: UnsafeCell::new(0) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         // nothing to do...
     }
 
diff --git a/src/libstd/sys/windows/mutex.rs b/src/libstd/sys/windows/mutex.rs
index 281eb294c65d8..63dfc640908e9 100644
--- a/src/libstd/sys/windows/mutex.rs
+++ b/src/libstd/sys/windows/mutex.rs
@@ -109,7 +109,7 @@ impl Mutex {
             0 => {}
             n => return n as *mut _,
         }
-        let mut re = box ReentrantMutex::uninitialized();
+        let re = box ReentrantMutex::uninitialized();
         re.init();
         let re = Box::into_raw(re);
         match self.lock.compare_and_swap(0, re as usize, Ordering::SeqCst) {
@@ -157,11 +157,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub fn uninitialized() -> ReentrantMutex {
+    pub const fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(MaybeUninit::uninit()) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         c::InitializeCriticalSection((&mut *self.inner.get()).as_mut_ptr());
     }
 
diff --git a/src/libstd/sys_common/remutex.rs b/src/libstd/sys_common/remutex.rs
index a1ad44a3666ed..4f19bbc467f33 100644
--- a/src/libstd/sys_common/remutex.rs
+++ b/src/libstd/sys_common/remutex.rs
@@ -3,7 +3,6 @@ use crate::marker;
 use crate::ops::Deref;
 use crate::panic::{RefUnwindSafe, UnwindSafe};
 use crate::sys::mutex as sys;
-use crate::sys_common::poison::{self, LockResult, TryLockError, TryLockResult};
 
 /// A re-entrant mutual exclusion
 ///
@@ -11,8 +10,7 @@ use crate::sys_common::poison::{self, LockResult, TryLockError, TryLockResult};
 /// available. The thread which has already locked the mutex can lock it
 /// multiple times without blocking, preventing a common source of deadlocks.
 pub struct ReentrantMutex<T> {
-    inner: Box<sys::ReentrantMutex>,
-    poison: poison::Flag,
+    inner: sys::ReentrantMutex,
     data: T,
 }
 
@@ -39,23 +37,30 @@ pub struct ReentrantMutexGuard<'a, T: 'a> {
     // funny underscores due to how Deref currently works (it disregards field
     // privacy).
     __lock: &'a ReentrantMutex<T>,
-    __poison: poison::Guard,
 }
 
 impl<T> !marker::Send for ReentrantMutexGuard<'_, T> {}
 
 impl<T> ReentrantMutex<T> {
     /// Creates a new reentrant mutex in an unlocked state.
-    pub fn new(t: T) -> ReentrantMutex<T> {
-        unsafe {
-            let mut mutex = ReentrantMutex {
-                inner: box sys::ReentrantMutex::uninitialized(),
-                poison: poison::Flag::new(),
-                data: t,
-            };
-            mutex.inner.init();
-            mutex
-        }
+    ///
+    /// # Unsafety
+    ///
+    /// This function is unsafe because it is required that `init` is called
+    /// once this mutex is in its final resting place, and only then are the
+    /// lock/unlock methods safe.
+    pub const unsafe fn new(t: T) -> ReentrantMutex<T> {
+        ReentrantMutex { inner: sys::ReentrantMutex::uninitialized(), data: t }
+    }
+
+    /// Initializes this mutex so it's ready for use.
+    ///
+    /// # Unsafety
+    ///
+    /// Unsafe to call more than once, and must be called after this will no
+    /// longer move in memory.
+    pub unsafe fn init(&self) {
+        self.inner.init();
     }
 
     /// Acquires a mutex, blocking the current thread until it is able to do so.
@@ -70,7 +75,7 @@ impl<T> ReentrantMutex<T> {
     /// If another user of this mutex panicked while holding the mutex, then
     /// this call will return failure if the mutex would otherwise be
     /// acquired.
-    pub fn lock(&self) -> LockResult<ReentrantMutexGuard<'_, T>> {
+    pub fn lock(&self) -> ReentrantMutexGuard<'_, T> {
         unsafe { self.inner.lock() }
         ReentrantMutexGuard::new(&self)
     }
@@ -87,12 +92,8 @@ impl<T> ReentrantMutex<T> {
     /// If another user of this mutex panicked while holding the mutex, then
     /// this call will return failure if the mutex would otherwise be
     /// acquired.
-    pub fn try_lock(&self) -> TryLockResult<ReentrantMutexGuard<'_, T>> {
-        if unsafe { self.inner.try_lock() } {
-            Ok(ReentrantMutexGuard::new(&self)?)
-        } else {
-            Err(TryLockError::WouldBlock)
-        }
+    pub fn try_lock(&self) -> Option<ReentrantMutexGuard<'_, T>> {
+        if unsafe { self.inner.try_lock() } { Some(ReentrantMutexGuard::new(&self)) } else { None }
     }
 }
 
@@ -108,11 +109,8 @@ impl<T> Drop for ReentrantMutex<T> {
 impl<T: fmt::Debug + 'static> fmt::Debug for ReentrantMutex<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.try_lock() {
-            Ok(guard) => f.debug_struct("ReentrantMutex").field("data", &*guard).finish(),
-            Err(TryLockError::Poisoned(err)) => {
-                f.debug_struct("ReentrantMutex").field("data", &**err.get_ref()).finish()
-            }
-            Err(TryLockError::WouldBlock) => {
+            Some(guard) => f.debug_struct("ReentrantMutex").field("data", &*guard).finish(),
+            None => {
                 struct LockedPlaceholder;
                 impl fmt::Debug for LockedPlaceholder {
                     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -127,11 +125,8 @@ impl<T: fmt::Debug + 'static> fmt::Debug for ReentrantMutex<T> {
 }
 
 impl<'mutex, T> ReentrantMutexGuard<'mutex, T> {
-    fn new(lock: &'mutex ReentrantMutex<T>) -> LockResult<ReentrantMutexGuard<'mutex, T>> {
-        poison::map_result(lock.poison.borrow(), |guard| ReentrantMutexGuard {
-            __lock: lock,
-            __poison: guard,
-        })
+    fn new(lock: &'mutex ReentrantMutex<T>) -> ReentrantMutexGuard<'mutex, T> {
+        ReentrantMutexGuard { __lock: lock }
     }
 }
 
@@ -147,7 +142,6 @@ impl<T> Drop for ReentrantMutexGuard<'_, T> {
     #[inline]
     fn drop(&mut self) {
         unsafe {
-            self.__lock.poison.done(&self.__poison);
             self.__lock.inner.unlock();
         }
     }
@@ -162,13 +156,17 @@ mod tests {
 
     #[test]
     fn smoke() {
-        let m = ReentrantMutex::new(());
+        let m = unsafe {
+            let m = ReentrantMutex::new(());
+            m.init();
+            m
+        };
         {
-            let a = m.lock().unwrap();
+            let a = m.lock();
             {
-                let b = m.lock().unwrap();
+                let b = m.lock();
                 {
-                    let c = m.lock().unwrap();
+                    let c = m.lock();
                     assert_eq!(*c, ());
                 }
                 assert_eq!(*b, ());
@@ -179,15 +177,19 @@ mod tests {
 
     #[test]
     fn is_mutex() {
-        let m = Arc::new(ReentrantMutex::new(RefCell::new(0)));
+        let m = unsafe {
+            let m = Arc::new(ReentrantMutex::new(RefCell::new(0)));
+            m.init();
+            m
+        };
         let m2 = m.clone();
-        let lock = m.lock().unwrap();
+        let lock = m.lock();
         let child = thread::spawn(move || {
-            let lock = m2.lock().unwrap();
+            let lock = m2.lock();
             assert_eq!(*lock.borrow(), 4950);
         });
         for i in 0..100 {
-            let lock = m.lock().unwrap();
+            let lock = m.lock();
             *lock.borrow_mut() += i;
         }
         drop(lock);
@@ -196,17 +198,21 @@ mod tests {
 
     #[test]
     fn trylock_works() {
-        let m = Arc::new(ReentrantMutex::new(()));
+        let m = unsafe {
+            let m = Arc::new(ReentrantMutex::new(()));
+            m.init();
+            m
+        };
         let m2 = m.clone();
-        let _lock = m.try_lock().unwrap();
-        let _lock2 = m.try_lock().unwrap();
+        let _lock = m.try_lock();
+        let _lock2 = m.try_lock();
         thread::spawn(move || {
             let lock = m2.try_lock();
-            assert!(lock.is_err());
+            assert!(lock.is_none());
         })
         .join()
         .unwrap();
-        let _lock3 = m.try_lock().unwrap();
+        let _lock3 = m.try_lock();
     }
 
     pub struct Answer<'a>(pub ReentrantMutexGuard<'a, RefCell<u32>>);
@@ -215,22 +221,4 @@ mod tests {
             *self.0.borrow_mut() = 42;
         }
     }
-
-    #[test]
-    fn poison_works() {
-        let m = Arc::new(ReentrantMutex::new(RefCell::new(0)));
-        let mc = m.clone();
-        let result = thread::spawn(move || {
-            let lock = mc.lock().unwrap();
-            *lock.borrow_mut() = 1;
-            let lock2 = mc.lock().unwrap();
-            *lock.borrow_mut() = 2;
-            let _answer = Answer(lock2);
-            panic!("What the answer to my lifetimes dilemma is?");
-        })
-        .join();
-        assert!(result.is_err());
-        let r = m.lock().err().unwrap().into_inner();
-        assert_eq!(*r.borrow(), 42);
-    }
 }
diff --git a/src/test/ui/eprint-on-tls-drop.rs b/src/test/ui/eprint-on-tls-drop.rs
new file mode 100644
index 0000000000000..77b04625bf91d
--- /dev/null
+++ b/src/test/ui/eprint-on-tls-drop.rs
@@ -0,0 +1,44 @@
+// run-pass
+// ignore-emscripten no processes
+
+use std::cell::RefCell;
+use std::env;
+use std::process::Command;
+
+fn main() {
+    let name = "YOU_ARE_THE_TEST";
+    if env::var(name).is_ok() {
+        TLS.with(|f| f.borrow().ensure());
+    } else {
+        let me = env::current_exe().unwrap();
+        let output = Command::new(&me).env(name, "1").output().unwrap();
+        println!("{:?}", output);
+        assert!(output.status.success());
+        let stderr = String::from_utf8(output.stderr).unwrap();
+        assert!(stderr.contains("hello new\n"));
+        assert!(stderr.contains("hello drop\n"));
+    }
+}
+
+struct Stuff {
+    _x: usize,
+}
+
+impl Stuff {
+    fn new() -> Self {
+        eprintln!("hello new");
+        Self { _x: 0 }
+    }
+
+    fn ensure(&self) {}
+}
+
+impl Drop for Stuff {
+    fn drop(&mut self) {
+        eprintln!("hello drop");
+    }
+}
+
+thread_local! {
+    static TLS: RefCell<Stuff> = RefCell::new(Stuff::new());
+}