Auto merge of #63482 - Centril:rollup-iyakgmg, r=Centril

Rollup of 10 pull requests

Successful merges:

 - #62108 (Use sharded maps for queries)
 - #63297 (Improve pointer offset method docs)
 - #63306 (Adapt AddRetag for shallow retagging)
 - #63406 (Suggest using a qualified path in patterns with inconsistent bindings)
 - #63431 (Revert "Simplify MIR generation for logical ops")
 - #63449 (resolve: Remove remaining special cases from built-in macros)
 - #63461 (docs: add stdlib env::var(_os) panic)
 - #63473 (Regression test for #56870)
 - #63474 (Add tests for issue #53598 and #57700)
 - #63480 (Fixes #63477)

Failed merges:

r? @ghost

src/librustc/ty/query/config.rs

@@ -11,7 +11,7 @@ use crate::util::profiling::ProfileCategory;
 use std::borrow::Cow;
 use std::hash::Hash;
 use std::fmt::Debug;
-use rustc_data_structures::sync::Lock;
+use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::fingerprint::Fingerprint;
 use crate::ich::StableHashingContext;
 
@@ -34,7 +34,7 @@ pub(crate) trait QueryAccessors<'tcx>: QueryConfig<'tcx> {
     fn query(key: Self::Key) -> Query<'tcx>;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
-    fn query_cache<'a>(tcx: TyCtxt<'tcx>) -> &'a Lock<QueryCache<'tcx, Self>>;
+    fn query_cache<'a>(tcx: TyCtxt<'tcx>) -> &'a Sharded<QueryCache<'tcx, Self>>;
 
     fn to_dep_node(tcx: TyCtxt<'tcx>, key: &Self::Key) -> DepNode;
 

src/librustc/ty/query/on_disk_cache.rs

@@ -1062,9 +1062,9 @@ where
         ::std::any::type_name::<Q>());
 
     time_ext(tcx.sess.time_extended(), Some(tcx.sess), desc, || {
-        let map = Q::query_cache(tcx).borrow();
-        assert!(map.active.is_empty());
-        for (key, entry) in map.results.iter() {
+        let shards = Q::query_cache(tcx).lock_shards();
+        assert!(shards.iter().all(|shard| shard.active.is_empty()));
+        for (key, entry) in shards.iter().flat_map(|shard| shard.results.iter()) {
             if Q::cache_on_disk(tcx, key.clone(), Some(&entry.value)) {
                 let dep_node = SerializedDepNodeIndex::new(entry.index.index());
 

src/librustc/ty/query/plumbing.rs

@@ -17,6 +17,7 @@ use errors::Diagnostic;
 use errors::FatalError;
 use rustc_data_structures::fx::{FxHashMap};
 use rustc_data_structures::sync::{Lrc, Lock};
+use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::thin_vec::ThinVec;
 #[cfg(not(parallel_compiler))]
 use rustc_data_structures::cold_path;
@@ -90,7 +91,7 @@ macro_rules! profq_query_msg {
 /// 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<'a, 'tcx, Q: QueryDescription<'tcx>> {
-    cache: &'a Lock<QueryCache<'tcx, Q>>,
+    cache: &'a Sharded<QueryCache<'tcx, Q>>,
     key: Q::Key,
     job: Lrc<QueryJob<'tcx>>,
 }
@@ -107,7 +108,7 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
     pub(super) fn try_get(tcx: TyCtxt<'tcx>, span: Span, key: &Q::Key) -> TryGetJob<'a, 'tcx, Q> {
         let cache = Q::query_cache(tcx);
         loop {
-            let mut lock = cache.borrow_mut();
+            let mut lock = cache.get_shard_by_value(key).lock();
             if let Some(value) = lock.results.get(key) {
                 profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
                 tcx.sess.profiler(|p| p.record_query_hit(Q::NAME));
@@ -191,7 +192,7 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
 
         let value = QueryValue::new(result.clone(), dep_node_index);
         {
-            let mut lock = cache.borrow_mut();
+            let mut lock = cache.get_shard_by_value(&key).lock();
             lock.active.remove(&key);
             lock.results.insert(key, value);
         }
@@ -215,7 +216,8 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> Drop for JobOwner<'a, 'tcx, Q> {
     #[cold]
     fn drop(&mut self) {
         // Poison the query so jobs waiting on it panic
-        self.cache.borrow_mut().active.insert(self.key.clone(), QueryResult::Poisoned);
+        let shard = self.cache.get_shard_by_value(&self.key);
+        shard.lock().active.insert(self.key.clone(), QueryResult::Poisoned);
         // Also signal the completion of the job, so waiters
         // will continue execution
         self.job.signal_complete();
@@ -708,7 +710,7 @@ macro_rules! define_queries_inner {
         use std::mem;
         #[cfg(parallel_compiler)]
         use ty::query::job::QueryResult;
-        use rustc_data_structures::sync::Lock;
+        use rustc_data_structures::sharded::Sharded;
         use crate::{
             rustc_data_structures::stable_hasher::HashStable,
             rustc_data_structures::stable_hasher::StableHasherResult,
@@ -740,18 +742,17 @@ macro_rules! define_queries_inner {
             pub fn collect_active_jobs(&self) -> Vec<Lrc<QueryJob<$tcx>>> {
                 let mut jobs = Vec::new();
 
-                // We use try_lock here since we are only called from the
+                // We use try_lock_shards here since we are only called from the
                 // deadlock handler, and this shouldn't be locked.
                 $(
-                    jobs.extend(
-                        self.$name.try_lock().unwrap().active.values().filter_map(|v|
-                            if let QueryResult::Started(ref job) = *v {
-                                Some(job.clone())
-                            } else {
-                                None
-                            }
-                        )
-                    );
+                    let shards = self.$name.try_lock_shards().unwrap();
+                    jobs.extend(shards.iter().flat_map(|shard| shard.active.values().filter_map(|v|
+                        if let QueryResult::Started(ref job) = *v {
+                            Some(job.clone())
+                        } else {
+                            None
+                        }
+                    )));
                 )*
 
                 jobs
@@ -773,26 +774,27 @@ macro_rules! define_queries_inner {
 
                 fn stats<'tcx, Q: QueryConfig<'tcx>>(
                     name: &'static str,
-                    map: &QueryCache<'tcx, Q>
+                    map: &Sharded<QueryCache<'tcx, Q>>,
                 ) -> QueryStats {
+                    let map = map.lock_shards();
                     QueryStats {
                         name,
                         #[cfg(debug_assertions)]
-                        cache_hits: map.cache_hits,
+                        cache_hits: map.iter().map(|shard| shard.cache_hits).sum(),
                         #[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>(),
-                        entry_count: map.results.len(),
+                        entry_count: map.iter().map(|shard| shard.results.len()).sum(),
                     }
                 }
 
                 $(
                     queries.push(stats::<queries::$name<'_>>(
                         stringify!($name),
-                        &*self.$name.lock()
+                        &self.$name,
                     ));
                 )*
 
@@ -967,7 +969,7 @@ macro_rules! define_queries_inner {
             }
 
             #[inline(always)]
-            fn query_cache<'a>(tcx: TyCtxt<$tcx>) -> &'a Lock<QueryCache<$tcx, Self>> {
+            fn query_cache<'a>(tcx: TyCtxt<$tcx>) -> &'a Sharded<QueryCache<$tcx, Self>> {
                 &tcx.queries.$name
             }
 
@@ -1099,7 +1101,7 @@ macro_rules! define_queries_struct {
             providers: IndexVec<CrateNum, Providers<$tcx>>,
             fallback_extern_providers: Box<Providers<$tcx>>,
 
-            $($(#[$attr])*  $name: Lock<QueryCache<$tcx, queries::$name<$tcx>>>,)*
+            $($(#[$attr])*  $name: Sharded<QueryCache<$tcx, queries::$name<$tcx>>>,)*
         }
     };
 }

src/librustc_mir/build/expr/into.rs

@@ -79,59 +79,66 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::LogicalOp { op, lhs, rhs } => {
                 // And:
                 //
-                // [block: If(lhs)] -true-> [else_block: dest = (rhs)]
-                //        | (false)
-                //  [shortcurcuit_block: dest = false]
+                // [block: If(lhs)] -true-> [else_block: If(rhs)] -true-> [true_block]
+                //        |                          | (false)
+                //        +----------false-----------+------------------> [false_block]
                 //
                 // Or:
                 //
-                // [block: If(lhs)] -false-> [else_block: dest = (rhs)]
-                //        | (true)
-                //  [shortcurcuit_block: dest = true]
+                // [block: If(lhs)] -false-> [else_block: If(rhs)] -true-> [true_block]
+                //        | (true)                   | (false)
+                //  [true_block]               [false_block]
 
-                let (shortcircuit_block, mut else_block, join_block) = (
+                let (true_block, false_block, mut else_block, join_block) = (
+                    this.cfg.start_new_block(),
                     this.cfg.start_new_block(),
                     this.cfg.start_new_block(),
                     this.cfg.start_new_block(),
                 );
 
                 let lhs = unpack!(block = this.as_local_operand(block, lhs));
                 let blocks = match op {
-                    LogicalOp::And => (else_block, shortcircuit_block),
-                    LogicalOp::Or => (shortcircuit_block, else_block),
+                    LogicalOp::And => (else_block, false_block),
+                    LogicalOp::Or => (true_block, else_block),
                 };
                 let term = TerminatorKind::if_(this.hir.tcx(), lhs, blocks.0, blocks.1);
                 this.cfg.terminate(block, source_info, term);
 
+                let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
+                let term = TerminatorKind::if_(this.hir.tcx(), rhs, true_block, false_block);
+                this.cfg.terminate(else_block, source_info, term);
+
                 this.cfg.push_assign_constant(
-                    shortcircuit_block,
+                    true_block,
                     source_info,
                     destination,
                     Constant {
                         span: expr_span,
                         ty: this.hir.bool_ty(),
                         user_ty: None,
-                        literal: match op {
-                            LogicalOp::And => this.hir.false_literal(),
-                            LogicalOp::Or => this.hir.true_literal(),
-                        },
+                        literal: this.hir.true_literal(),
                     },
                 );
-                this.cfg.terminate(
-                    shortcircuit_block,
+
+                this.cfg.push_assign_constant(
+                    false_block,
                     source_info,
-                    TerminatorKind::Goto { target: join_block },
+                    destination,
+                    Constant {
+                        span: expr_span,
+                        ty: this.hir.bool_ty(),
+                        user_ty: None,
+                        literal: this.hir.false_literal(),
+                    },
                 );
 
-                let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
-                this.cfg.push_assign(
-                    else_block,
+                this.cfg.terminate(
+                    true_block,
                     source_info,
-                    destination,
-                    Rvalue::Use(rhs),
+                    TerminatorKind::Goto { target: join_block },
                 );
                 this.cfg.terminate(
-                    else_block,
+                    false_block,
                     source_info,
                     TerminatorKind::Goto { target: join_block },
                 );

src/librustc_mir/transform/add_retag.rs

@@ -42,9 +42,8 @@ fn is_stable(
     }
 }
 
-/// Determine whether this type may have a reference in it, recursing below compound types but
-/// not below references.
-fn may_have_reference<'tcx>(ty: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> bool {
+/// Determine whether this type may be a reference (or box), and thus needs retagging.
+fn may_be_reference<'tcx>(ty: Ty<'tcx>) -> bool {
     match ty.sty {
         // Primitive types that are not references
         ty::Bool | ty::Char |
@@ -55,15 +54,12 @@ fn may_have_reference<'tcx>(ty: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> bool {
         // References
         ty::Ref(..) => true,
         ty::Adt(..) if ty.is_box() => true,
-        // Compound types
-        ty::Array(ty, ..) | ty::Slice(ty) =>
-            may_have_reference(ty, tcx),
-        ty::Tuple(tys) =>
-            tys.iter().any(|ty| may_have_reference(ty.expect_ty(), tcx)),
-        ty::Adt(adt, substs) =>
-            adt.variants.iter().any(|v| v.fields.iter().any(|f|
-                may_have_reference(f.ty(tcx, substs), tcx)
-            )),
+        // Compound types are not references
+        ty::Array(..) |
+        ty::Slice(..) |
+        ty::Tuple(..) |
+        ty::Adt(..) =>
+            false,
         // Conservative fallback
         _ => true,
     }
@@ -80,7 +76,7 @@ impl MirPass for AddRetag {
             // FIXME: Instead of giving up for unstable places, we should introduce
             // a temporary and retag on that.
             is_stable(place.as_ref())
-                && may_have_reference(place.ty(&*local_decls, tcx).ty, tcx)
+                && may_be_reference(place.ty(&*local_decls, tcx).ty)
         };
 
         // PART 1

src/librustc_resolve/build_reduced_graph.rs

@@ -126,8 +126,6 @@ impl<'a> Resolver<'a> {
         };
         if let Some(id) = self.definitions.as_local_node_id(def_id) {
             self.local_macro_def_scopes[&id]
-        } else if self.is_builtin_macro(Some(def_id)) {
-            self.injected_crate.unwrap_or(self.graph_root)
         } else {
             let module_def_id = ty::DefIdTree::parent(&*self, def_id).unwrap();
             self.get_module(module_def_id)
@@ -596,11 +594,6 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 };
 
                 self.r.populate_module_if_necessary(module);
-                if let Some(name) = self.r.session.parse_sess.injected_crate_name.try_get() {
-                    if name.as_str() == ident.name.as_str() {
-                        self.r.injected_crate = Some(module);
-                    }
-                }
 
                 let used = self.process_legacy_macro_imports(item, module);
                 let binding =

src/librustc_resolve/diagnostics.rs

@@ -20,7 +20,7 @@ use syntax_pos::{BytePos, Span, MultiSpan};
 
 use crate::resolve_imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
 use crate::{path_names_to_string, KNOWN_TOOLS};
-use crate::{CrateLint, LegacyScope, Module, ModuleOrUniformRoot};
+use crate::{BindingError, CrateLint, LegacyScope, Module, ModuleOrUniformRoot};
 use crate::{PathResult, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Segment};
 
 type Res = def::Res<ast::NodeId>;
@@ -207,21 +207,32 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::VariableNotBoundInPattern(binding_error) => {
-                let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
+                let BindingError { name, target, origin, could_be_path } = binding_error;
+
+                let target_sp = target.iter().copied().collect::<Vec<_>>();
+                let origin_sp = origin.iter().copied().collect::<Vec<_>>();
+
                 let msp = MultiSpan::from_spans(target_sp.clone());
-                let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
+                let msg = format!("variable `{}` is not bound in all patterns", name);
                 let mut err = self.session.struct_span_err_with_code(
                     msp,
                     &msg,
                     DiagnosticId::Error("E0408".into()),
                 );
                 for sp in target_sp {
-                    err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
+                    err.span_label(sp, format!("pattern doesn't bind `{}`", name));
                 }
-                let origin_sp = binding_error.origin.iter().cloned();
                 for sp in origin_sp {
                     err.span_label(sp, "variable not in all patterns");
                 }
+                if *could_be_path {
+                    let help_msg = format!(
+                        "if you meant to match on a variant or a `const` item, consider \
+                         making the path in the pattern qualified: `?::{}`",
+                         name,
+                     );
+                    err.span_help(span, &help_msg);
+                }
                 err
             }
             ResolutionError::VariableBoundWithDifferentMode(variable_name,