Rollup of 8 pull requests

compiler/rustc_hir_typeck/src/closure.rs

@@ -14,7 +14,7 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt};
 use rustc_middle::ty::{self, GenericArgs, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_span::def_id::LocalDefId;
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::error_reporting::traits::ArgKind;
 use rustc_trait_selection::traits;
@@ -539,6 +539,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// we identify the `FnOnce<Args, Output = ?Fut>` bound, and if the output type is
     /// an inference variable `?Fut`, we check if that is bounded by a `Future<Output = Ty>`
     /// projection.
+    ///
+    /// This function is actually best-effort with the return type; if we don't find a
+    /// `Future` projection, we still will return arguments that we extracted from the `FnOnce`
+    /// projection, and the output will be an unconstrained type variable instead.
     fn extract_sig_from_projection_and_future_bound(
         &self,
         cause_span: Option<Span>,
@@ -564,24 +568,43 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         // FIXME: We may want to elaborate here, though I assume this will be exceedingly rare.
+        let mut return_ty = None;
         for bound in self.obligations_for_self_ty(return_vid) {
             if let Some(ret_projection) = bound.predicate.as_projection_clause()
                 && let Some(ret_projection) = ret_projection.no_bound_vars()
                 && self.tcx.is_lang_item(ret_projection.def_id(), LangItem::FutureOutput)
             {
-                let sig = projection.rebind(self.tcx.mk_fn_sig(
-                    input_tys,
-                    ret_projection.term.expect_type(),
-                    false,
-                    hir::Safety::Safe,
-                    Abi::Rust,
-                ));
-
-                return Some(ExpectedSig { cause_span, sig });
+                return_ty = Some(ret_projection.term.expect_type());
+                break;
             }
         }
 
-        None
+        // SUBTLE: If we didn't find a `Future<Output = ...>` bound for the return
+        // vid, we still want to attempt to provide inference guidance for the async
+        // closure's arguments. Instantiate a new vid to plug into the output type.
+        //
+        // You may be wondering, what if it's higher-ranked? Well, given that we
+        // found a type variable for the `FnOnce::Output` projection above, we know
+        // that the output can't mention any of the vars.
+        //
+        // Also note that we use a fresh var here for the signature since the signature
+        // records the output of the *future*, and `return_vid` above is the type
+        // variable of the future, not its output.
+        //
+        // FIXME: We probably should store this signature inference output in a way
+        // that does not misuse a `FnSig` type, but that can be done separately.
+        let return_ty =
+            return_ty.unwrap_or_else(|| self.next_ty_var(cause_span.unwrap_or(DUMMY_SP)));
+
+        let sig = projection.rebind(self.tcx.mk_fn_sig(
+            input_tys,
+            return_ty,
+            false,
+            hir::Safety::Safe,
+            Abi::Rust,
+        ));
+
+        return Some(ExpectedSig { cause_span, sig });
     }
 
     fn sig_of_closure(

compiler/rustc_middle/src/query/mod.rs

@@ -65,10 +65,9 @@ use crate::query::plumbing::{
 };
 use crate::traits::query::{
     CanonicalAliasGoal, CanonicalPredicateGoal, CanonicalTyGoal,
-    CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
-    CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal, DropckConstraint,
-    DropckOutlivesResult, MethodAutoderefStepsResult, NoSolution, NormalizationResult,
-    OutlivesBound,
+    CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpNormalizeGoal,
+    CanonicalTypeOpProvePredicateGoal, DropckConstraint, DropckOutlivesResult,
+    MethodAutoderefStepsResult, NoSolution, NormalizationResult, OutlivesBound,
 };
 use crate::traits::{
     specialization_graph, CodegenObligationError, EvaluationResult, ImplSource,
@@ -2090,26 +2089,6 @@ rustc_queries! {
         desc { "evaluating `type_op_ascribe_user_type` `{:?}`", goal.value.value }
     }
 
-    /// Do not call this query directly: part of the `Eq` type-op
-    query type_op_eq(
-        goal: CanonicalTypeOpEqGoal<'tcx>
-    ) -> Result<
-        &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, ()>>,
-        NoSolution,
-    > {
-        desc { "evaluating `type_op_eq` `{:?}`", goal.value.value }
-    }
-
-    /// Do not call this query directly: part of the `Subtype` type-op
-    query type_op_subtype(
-        goal: CanonicalTypeOpSubtypeGoal<'tcx>
-    ) -> Result<
-        &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, ()>>,
-        NoSolution,
-    > {
-        desc { "evaluating `type_op_subtype` `{:?}`", goal.value.value }
-    }
-
     /// Do not call this query directly: part of the `ProvePredicate` type-op
     query type_op_prove_predicate(
         goal: CanonicalTypeOpProvePredicateGoal<'tcx>

compiler/rustc_mir_transform/src/coroutine/by_move_body.rs

@@ -78,6 +78,8 @@ use rustc_middle::mir::{self, dump_mir, MirPass};
 use rustc_middle::ty::{self, InstanceKind, Ty, TyCtxt, TypeVisitableExt};
 use rustc_target::abi::{FieldIdx, VariantIdx};
 
+use crate::pass_manager::validate_body;
+
 pub struct ByMoveBody;
 
 impl<'tcx> MirPass<'tcx> for ByMoveBody {
@@ -131,20 +133,40 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody {
             |(parent_field_idx, parent_capture), (child_field_idx, child_capture)| {
                 // Store this set of additional projections (fields and derefs).
                 // We need to re-apply them later.
-                let child_precise_captures =
-                    &child_capture.place.projections[parent_capture.place.projections.len()..];
+                let mut child_precise_captures = child_capture.place.projections
+                    [parent_capture.place.projections.len()..]
+                    .to_vec();
 
-                // If the parent captures by-move, and the child captures by-ref, then we
-                // need to peel an additional `deref` off of the body of the child.
-                let needs_deref = child_capture.is_by_ref() && !parent_capture.is_by_ref();
-                if needs_deref {
-                    assert_ne!(
-                        coroutine_kind,
-                        ty::ClosureKind::FnOnce,
+                // If the parent capture is by-ref, then we need to apply an additional
+                // deref before applying any further projections to this place.
+                if parent_capture.is_by_ref() {
+                    child_precise_captures.insert(
+                        0,
+                        Projection { ty: parent_capture.place.ty(), kind: ProjectionKind::Deref },
+                    );
+                }
+                // If the child capture is by-ref, then we need to apply a "ref"
+                // projection (i.e. `&`) at the end. But wait! We don't have that
+                // as a projection kind. So instead, we can apply its dual and
+                // *peel* a deref off of the place when it shows up in the MIR body.
+                // Luckily, by construction this is always possible.
+                let peel_deref = if child_capture.is_by_ref() {
+                    assert!(
+                        parent_capture.is_by_ref() || coroutine_kind != ty::ClosureKind::FnOnce,
                         "`FnOnce` coroutine-closures return coroutines that capture from \
                         their body; it will always result in a borrowck error!"
                     );
-                }
+                    true
+                } else {
+                    false
+                };
+
+                // Regarding the behavior above, you may think that it's redundant to both
+                // insert a deref and then peel a deref if the parent and child are both
+                // captured by-ref. This would be correct, except for the case where we have
+                // precise capturing projections, since the inserted deref is to the *beginning*
+                // and the peeled deref is at the *end*. I cannot seem to actually find a
+                // case where this happens, though, but let's keep this code flexible.
 
                 // Finally, store the type of the parent's captured place. We need
                 // this when building the field projection in the MIR body later on.
@@ -164,7 +186,7 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody {
                     (
                         FieldIdx::from_usize(parent_field_idx + num_args),
                         parent_capture_ty,
-                        needs_deref,
+                        peel_deref,
                         child_precise_captures,
                     ),
                 )
@@ -192,6 +214,10 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody {
         let mut by_move_body = body.clone();
         MakeByMoveBody { tcx, field_remapping, by_move_coroutine_ty }.visit_body(&mut by_move_body);
         dump_mir(tcx, false, "coroutine_by_move", &0, &by_move_body, |_, _| Ok(()));
+
+        // Let's just always validate this body.
+        validate_body(tcx, &mut by_move_body, "Initial coroutine_by_move body".to_string());
+
         // FIXME: use query feeding to generate the body right here and then only store the `DefId` of the new body.
         by_move_body.source = mir::MirSource::from_instance(InstanceKind::CoroutineKindShim {
             coroutine_def_id: coroutine_def_id.to_def_id(),
@@ -202,7 +228,7 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody {
 
 struct MakeByMoveBody<'tcx> {
     tcx: TyCtxt<'tcx>,
-    field_remapping: UnordMap<FieldIdx, (FieldIdx, Ty<'tcx>, bool, &'tcx [Projection<'tcx>])>,
+    field_remapping: UnordMap<FieldIdx, (FieldIdx, Ty<'tcx>, bool, Vec<Projection<'tcx>>)>,
     by_move_coroutine_ty: Ty<'tcx>,
 }
 
@@ -223,14 +249,14 @@ impl<'tcx> MutVisitor<'tcx> for MakeByMoveBody<'tcx> {
         if place.local == ty::CAPTURE_STRUCT_LOCAL
             && let Some((&mir::ProjectionElem::Field(idx, _), projection)) =
                 place.projection.split_first()
-            && let Some(&(remapped_idx, remapped_ty, needs_deref, bridging_projections)) =
+            && let Some(&(remapped_idx, remapped_ty, peel_deref, ref bridging_projections)) =
                 self.field_remapping.get(&idx)
         {
             // As noted before, if the parent closure captures a field by value, and
             // the child captures a field by ref, then for the by-move body we're
             // generating, we also are taking that field by value. Peel off a deref,
             // since a layer of ref'ing has now become redundant.
-            let final_projections = if needs_deref {
+            let final_projections = if peel_deref {
                 let Some((mir::ProjectionElem::Deref, projection)) = projection.split_first()
                 else {
                     bug!(

compiler/rustc_session/src/session.rs

@@ -1188,7 +1188,12 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
 
     // Sanitizers can only be used on platforms that we know have working sanitizer codegen.
     let supported_sanitizers = sess.target.options.supported_sanitizers;
-    let unsupported_sanitizers = sess.opts.unstable_opts.sanitizer - supported_sanitizers;
+    let mut unsupported_sanitizers = sess.opts.unstable_opts.sanitizer - supported_sanitizers;
+    // Niche: if `fixed-x18`, or effectively switching on `reserved-x18` flag, is enabled
+    // we should allow Shadow Call Stack sanitizer.
+    if sess.opts.unstable_opts.fixed_x18 && sess.target.arch == "aarch64" {
+        unsupported_sanitizers -= SanitizerSet::SHADOWCALLSTACK;
+    }
     match unsupported_sanitizers.into_iter().count() {
         0 => {}
         1 => {

compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs

@@ -16,12 +16,10 @@ use crate::traits::{ObligationCause, ObligationCtxt};
 
 pub mod ascribe_user_type;
 pub mod custom;
-pub mod eq;
 pub mod implied_outlives_bounds;
 pub mod normalize;
 pub mod outlives;
 pub mod prove_predicate;
-pub mod subtype;
 
 pub use rustc_middle::traits::query::type_op::*;
 

compiler/rustc_traits/src/type_op.rs

@@ -10,18 +10,14 @@ use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use rustc_trait_selection::traits::query::type_op::ascribe_user_type::{
     type_op_ascribe_user_type_with_span, AscribeUserType,
 };
-use rustc_trait_selection::traits::query::type_op::eq::Eq;
 use rustc_trait_selection::traits::query::type_op::normalize::Normalize;
 use rustc_trait_selection::traits::query::type_op::prove_predicate::ProvePredicate;
-use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, ObligationCtxt};
 
 pub(crate) fn provide(p: &mut Providers) {
     *p = Providers {
         type_op_ascribe_user_type,
-        type_op_eq,
         type_op_prove_predicate,
-        type_op_subtype,
         type_op_normalize_ty,
         type_op_normalize_clause,
         type_op_normalize_fn_sig,
@@ -39,16 +35,6 @@ fn type_op_ascribe_user_type<'tcx>(
     })
 }
 
-fn type_op_eq<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Eq<'tcx>>>,
-) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
-    tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |ocx, key| {
-        let (param_env, Eq { a, b }) = key.into_parts();
-        Ok(ocx.eq(&ObligationCause::dummy(), param_env, a, b)?)
-    })
-}
-
 fn type_op_normalize<'tcx, T>(
     ocx: &ObligationCtxt<'_, 'tcx>,
     key: ParamEnvAnd<'tcx, Normalize<T>>,
@@ -91,16 +77,6 @@ fn type_op_normalize_poly_fn_sig<'tcx>(
     tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
 }
 
-fn type_op_subtype<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Subtype<'tcx>>>,
-) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
-    tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |ocx, key| {
-        let (param_env, Subtype { sub, sup }) = key.into_parts();
-        Ok(ocx.sup(&ObligationCause::dummy(), param_env, sup, sub)?)
-    })
-}
-
 fn type_op_prove_predicate<'tcx>(
     tcx: TyCtxt<'tcx>,
     canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, ProvePredicate<'tcx>>>,

src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile

@@ -62,9 +62,9 @@ COPY host-x86_64/dist-x86_64-linux/build-clang.sh /tmp/
 RUN ./build-clang.sh
 ENV CC=clang CXX=clang++
 
-# rustc's LLVM needs zstd.
-COPY scripts/zstd.sh /tmp/
-RUN ./zstd.sh
+# Build zstd to enable `llvm.libzstd`.
+COPY host-x86_64/dist-x86_64-linux/build-zstd.sh /tmp/
+RUN ./build-zstd.sh
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/host-x86_64/x86_64-gnu/Dockerfile

@@ -28,5 +28,6 @@ ENV RUST_CONFIGURE_ARGS \
  --build=x86_64-unknown-linux-gnu \
  --enable-sanitizers \
  --enable-profiler \
- --enable-compiler-docs
+ --enable-compiler-docs \
+ --set llvm.libzstd=true
 ENV SCRIPT python3 ../x.py --stage 2 test

src/doc/rustc/src/platform-support/android.md

@@ -61,3 +61,8 @@ Currently the `riscv64-linux-android` target requires the following architecture
 * `Zba` (address calculation instructions)
 * `Zbb` (base instructions)
 * `Zbs` (single-bit instructions)
+
+### aarch64-linux-android on Nightly compilers
+
+As soon as `-Zfixed-x18` compiler flag is supplied, the [`ShadowCallStack` sanitizer](https://releases.llvm.org/7.0.1/tools/clang/docs/ShadowCallStack.html)
+instrumentation is also made avaiable by supplying the second compiler flag `-Zsanitizer=shadow-call-stack`.