Auto merge of rust-lang#115787 - Mark-Simulacrum:stable-next, r=Mark-…

…Simulacrum

[stable] 1.72.1 release

This backports:

*  Remove assert that checks type equality rust-lang#115215
*  implied bounds: do not ICE on unconstrained region vars rust-lang#115559
*  rustdoc: correctly deal with self ty params when eliding default object lifetimes rust-lang#115276
*  Stop emitting non-power-of-two vectors in (non-portable-SIMD) codegen rust-lang#115236
*  Normalize before checking if local is freeze in deduced_param_attrs rust-lang#114948

Some cherry-picks required merge conflict resolution, we'll see if I got it right based on CI (rustdoc fix and LLVM codegen test).

r? `@Mark-Simulacrum`

RELEASES.md

@@ -1,3 +1,13 @@
+Version 1.72.1 (2023-09-14)
+===========================
+
+- [Adjust codegen change to improve LLVM codegen](https://github.com/rust-lang/rust/pull/115236)
+- [rustdoc: Fix self ty params in objects with lifetimes](https://github.com/rust-lang/rust/pull/115276)
+- [Fix regression in compile times](https://github.com/rust-lang/rust/pull/114948)
+- Resolve some ICE regressions in the compiler:
+  - [#115215](https://github.com/rust-lang/rust/pull/115215)
+  - [#115559](https://github.com/rust-lang/rust/pull/115559)
+
 Version 1.72.0 (2023-08-24)
 ==========================
 

compiler/rustc_codegen_llvm/src/type_of.rs

@@ -431,7 +431,11 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
 
         // Vectors, even for non-power-of-two sizes, have the same layout as
         // arrays but don't count as aggregate types
+        // While LLVM theoretically supports non-power-of-two sizes, and they
+        // often work fine, sometimes x86-isel deals with them horribly
+        // (see #115212) so for now only use power-of-two ones.
         if let FieldsShape::Array { count, .. } = self.layout.fields()
+            && count.is_power_of_two()
             && let element = self.field(cx, 0)
             && element.ty.is_integral()
         {

compiler/rustc_codegen_ssa/src/mir/locals.rs

@@ -7,7 +7,6 @@ use rustc_index::IndexVec;
 use rustc_middle::mir;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use std::ops::{Index, IndexMut};
-
 pub(super) struct Locals<'tcx, V> {
     values: IndexVec<mir::Local, LocalRef<'tcx, V>>,
 }
@@ -36,17 +35,18 @@ impl<'tcx, V> Locals<'tcx, V> {
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub(super) fn initialize_locals(&mut self, values: Vec<LocalRef<'tcx, Bx::Value>>) {
         assert!(self.locals.values.is_empty());
-
+        // FIXME(#115215): After #115025 get's merged this might not be necessary
         for (local, value) in values.into_iter().enumerate() {
             match value {
                 LocalRef::Place(_) | LocalRef::UnsizedPlace(_) | LocalRef::PendingOperand => (),
                 LocalRef::Operand(op) => {
                     let local = mir::Local::from_usize(local);
                     let expected_ty = self.monomorphize(self.mir.local_decls[local].ty);
-                    assert_eq!(expected_ty, op.layout.ty, "unexpected initial operand type");
+                    if expected_ty != op.layout.ty {
+                        warn!("Unexpected initial operand type. See the issues/114858");
+                    }
                 }
             }
-
             self.locals.values.push(value);
         }
     }

compiler/rustc_mir_transform/src/deduce_param_attrs.rs

@@ -203,7 +203,12 @@ pub fn deduced_param_attrs<'tcx>(
         body.local_decls.iter().skip(1).take(body.arg_count).enumerate().map(
             |(arg_index, local_decl)| DeducedParamAttrs {
                 read_only: !deduce_read_only.mutable_args.contains(arg_index)
-                    && local_decl.ty.is_freeze(tcx, param_env),
+                    // We must normalize here to reveal opaques and normalize
+                    // their substs, otherwise we'll see exponential blow-up in
+                    // compile times: #113372
+                    && tcx
+                        .normalize_erasing_regions(param_env, local_decl.ty)
+                        .is_freeze(tcx, param_env),
             },
         ),
     );

compiler/rustc_trait_selection/src/traits/outlives_bounds.rs

@@ -57,16 +57,12 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> {
         let ty = OpportunisticRegionResolver::new(self).fold_ty(ty);
 
         // We do not expect existential variables in implied bounds.
-        // We may however encounter unconstrained lifetime variables in invalid
-        // code. See #110161 for context.
+        // We may however encounter unconstrained lifetime variables
+        // in very rare cases.
+        //
+        // See `ui/implied-bounds/implied-bounds-unconstrained-2.rs` for
+        // an example.
         assert!(!ty.has_non_region_infer());
-        if ty.has_infer() {
-            self.tcx.sess.delay_span_bug(
-                self.tcx.def_span(body_id),
-                "skipped implied_outlives_bounds due to unconstrained lifetimes",
-            );
-            return vec![];
-        }
 
         let mut canonical_var_values = OriginalQueryValues::default();
         let canonical_ty =

src/librustdoc/clean/mod.rs

@@ -167,8 +167,7 @@ fn clean_generic_bound<'tcx>(
             let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(cx.tcx, def_id));
 
             let generic_args = clean_generic_args(generic_args, cx);
-            let GenericArgs::AngleBracketed { bindings, .. } = generic_args
-            else {
+            let GenericArgs::AngleBracketed { bindings, .. } = generic_args else {
                 bug!("clean: parenthesized `GenericBound::LangItemTrait`");
             };
 
@@ -1818,33 +1817,46 @@ fn can_elide_trait_object_lifetime_bound<'tcx>(
 #[derive(Debug)]
 pub(crate) enum ContainerTy<'tcx> {
     Ref(ty::Region<'tcx>),
-    Regular { ty: DefId, substs: ty::Binder<'tcx, &'tcx [ty::GenericArg<'tcx>]>, arg: usize },
+    Regular {
+        ty: DefId,
+        args: ty::Binder<'tcx, &'tcx [ty::GenericArg<'tcx>]>,
+        has_self: bool,
+        arg: usize,
+    },
 }
 
 impl<'tcx> ContainerTy<'tcx> {
     fn object_lifetime_default(self, tcx: TyCtxt<'tcx>) -> ObjectLifetimeDefault<'tcx> {
         match self {
             Self::Ref(region) => ObjectLifetimeDefault::Arg(region),
-            Self::Regular { ty: container, substs, arg: index } => {
+            Self::Regular { ty: container, args, has_self, arg: index } => {
                 let (DefKind::Struct
                 | DefKind::Union
                 | DefKind::Enum
-                | DefKind::TyAlias
-                | DefKind::Trait
-                | DefKind::AssocTy
-                | DefKind::Variant) = tcx.def_kind(container)
+                | DefKind::TyAlias { .. }
+                | DefKind::Trait) = tcx.def_kind(container)
                 else {
                     return ObjectLifetimeDefault::Empty;
                 };
 
                 let generics = tcx.generics_of(container);
-                let param = generics.params[index].def_id;
-                let default = tcx.object_lifetime_default(param);
+                debug_assert_eq!(generics.parent_count, 0);
+
+                // If the container is a trait object type, the arguments won't contain the self type but the
+                // generics of the corresponding trait will. In such a case, offset the index by one.
+                // For comparison, if the container is a trait inside a bound, the arguments do contain the
+                // self type.
+                let offset =
+                    if !has_self && generics.parent.is_none() && generics.has_self { 1 } else { 0 };
+                let param = generics.params[index + offset].def_id;
 
+                let default = tcx.object_lifetime_default(param);
                 match default {
                     rbv::ObjectLifetimeDefault::Param(lifetime) => {
+                        // The index is relative to the parent generics but since we don't have any,
+                        // we don't need to translate it.
                         let index = generics.param_def_id_to_index[&lifetime];
-                        let arg = substs.skip_binder()[index as usize].expect_region();
+                        let arg = args.skip_binder()[index as usize].expect_region();
                         ObjectLifetimeDefault::Arg(arg)
                     }
                     rbv::ObjectLifetimeDefault::Empty => ObjectLifetimeDefault::Empty,

src/librustdoc/clean/utils.rs

@@ -54,8 +54,7 @@ pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
     let primitives = local_crate.primitives(cx.tcx);
     let keywords = local_crate.keywords(cx.tcx);
     {
-        let ItemKind::ModuleItem(ref mut m) = *module.kind
-        else { unreachable!() };
+        let ItemKind::ModuleItem(ref mut m) = *module.kind else { unreachable!() };
         m.items.extend(primitives.iter().map(|&(def_id, prim)| {
             Item::from_def_id_and_parts(
                 def_id,
@@ -74,18 +73,15 @@ pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
 
 pub(crate) fn substs_to_args<'tcx>(
     cx: &mut DocContext<'tcx>,
-    substs: ty::Binder<'tcx, &'tcx [ty::subst::GenericArg<'tcx>]>,
-    mut skip_first: bool,
+    args: ty::Binder<'tcx, &'tcx [ty::GenericArg<'tcx>]>,
+    has_self: bool,
     container: Option<DefId>,
 ) -> Vec<GenericArg> {
+    let mut skip_first = has_self;
     let mut ret_val =
-        Vec::with_capacity(substs.skip_binder().len().saturating_sub(if skip_first {
-            1
-        } else {
-            0
-        }));
+        Vec::with_capacity(args.skip_binder().len().saturating_sub(if skip_first { 1 } else { 0 }));
 
-    ret_val.extend(substs.iter().enumerate().filter_map(|(index, kind)| {
+    ret_val.extend(args.iter().enumerate().filter_map(|(index, kind)| {
         match kind.skip_binder().unpack() {
             GenericArgKind::Lifetime(lt) => {
                 Some(GenericArg::Lifetime(clean_middle_region(lt).unwrap_or(Lifetime::elided())))
@@ -100,7 +96,8 @@ pub(crate) fn substs_to_args<'tcx>(
                 None,
                 container.map(|container| crate::clean::ContainerTy::Regular {
                     ty: container,
-                    substs,
+                    args,
+                    has_self,
                     arg: index,
                 }),
             ))),

src/version

@@ -1 +1 @@
-1.72.0
+1.72.1

tests/codegen/mem-replace-simple-type.rs

@@ -34,12 +34,21 @@ pub fn replace_ref_str<'a>(r: &mut &'a str, v: &'a str) -> &'a str {
 }
 
 #[no_mangle]
-// CHECK-LABEL: @replace_short_array(
-pub fn replace_short_array(r: &mut [u32; 3], v: [u32; 3]) -> [u32; 3] {
+// CHECK-LABEL: @replace_short_array_3(
+pub fn replace_short_array_3(r: &mut [u32; 3], v: [u32; 3]) -> [u32; 3] {
     // CHECK-NOT: alloca
-    // CHECK: %[[R:.+]] = load <3 x i32>, ptr %r, align 4
-    // CHECK: store <3 x i32> %[[R]], ptr %0
-    // CHECK: %[[V:.+]] = load <3 x i32>, ptr %v, align 4
-    // CHECK: store <3 x i32> %[[V]], ptr %r
+    // CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %result, ptr align 4 %r, i64 12, i1 false)
+    // CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %r, ptr align 4 %v, i64 12, i1 false)
+    std::mem::replace(r, v)
+}
+
+#[no_mangle]
+// CHECK-LABEL: @replace_short_array_4(
+pub fn replace_short_array_4(r: &mut [u32; 4], v: [u32; 4]) -> [u32; 4] {
+    // CHECK-NOT: alloca
+    // CHECK: %[[R:.+]] = load <4 x i32>, ptr %r, align 4
+    // CHECK: store <4 x i32> %[[R]], ptr %result
+    // CHECK: %[[V:.+]] = load <4 x i32>, ptr %v, align 4
+    // CHECK: store <4 x i32> %[[V]], ptr %r
     std::mem::replace(r, v)
 }

tests/codegen/swap-small-types.rs

@@ -11,11 +11,12 @@ type RGB48 = [u16; 3];
 // CHECK-LABEL: @swap_rgb48_manually(
 #[no_mangle]
 pub fn swap_rgb48_manually(x: &mut RGB48, y: &mut RGB48) {
-    // CHECK-NOT: alloca
-    // CHECK: %[[TEMP0:.+]] = load <3 x i16>, ptr %x, align 2
-    // CHECK: %[[TEMP1:.+]] = load <3 x i16>, ptr %y, align 2
-    // CHECK: store <3 x i16> %[[TEMP1]], ptr %x, align 2
-    // CHECK: store <3 x i16> %[[TEMP0]], ptr %y, align 2
+    // FIXME: See #115212 for why this has an alloca again
+
+    // CHECK: alloca [3 x i16], align 2
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
 
     let temp = *x;
     *x = *y;
@@ -25,11 +26,25 @@ pub fn swap_rgb48_manually(x: &mut RGB48, y: &mut RGB48) {
 // CHECK-LABEL: @swap_rgb48
 #[no_mangle]
 pub fn swap_rgb48(x: &mut RGB48, y: &mut RGB48) {
+    // FIXME: See #115212 for why this has an alloca again
+
+    // CHECK: alloca [3 x i16], align 2
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
+    // CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
+    swap(x, y)
+}
+
+type RGBA64 = [u16; 4];
+
+// CHECK-LABEL: @swap_rgba64
+#[no_mangle]
+pub fn swap_rgba64(x: &mut RGBA64, y: &mut RGBA64) {
     // CHECK-NOT: alloca
-    // CHECK: load <3 x i16>
-    // CHECK: load <3 x i16>
-    // CHECK: store <3 x i16>
-    // CHECK: store <3 x i16>
+    // CHECK-DAG: %[[XVAL:.+]] = load <4 x i16>, ptr %x, align 2
+    // CHECK-DAG: %[[YVAL:.+]] = load <4 x i16>, ptr %y, align 2
+    // CHECK-DAG: store <4 x i16> %[[YVAL]], ptr %x, align 2
+    // CHECK-DAG: store <4 x i16> %[[XVAL]], ptr %y, align 2
     swap(x, y)
 }
 

tests/rustdoc/inline_cross/auxiliary/dyn_trait.rs

@@ -65,3 +65,22 @@ pub trait HigherRankedBoundTrait1<'e> where for<'l> Self: 'e + 'l {}
 pub trait AmbiguousBoundTrait<'a, 'b>: 'a + 'b {}
 
 pub struct AmbiguousBoundWrapper<'a, 'b, T: ?Sized + 'a + 'b>(&'a T, &'b T);
+
+// Trait objects inside of another trait object, a trait bound or an associated type.
+
+pub trait Inner {}
+pub trait Outer<T: ?Sized> {}
+pub trait Base {
+    type Type<T: ?Sized>;
+}
+impl Base for () {
+    type Type<T: ?Sized> = ();
+}
+
+pub type NestedTraitObjects = dyn Outer<dyn Inner>;
+
+pub fn apit_rpit(o: impl Outer<dyn Inner>) -> impl Outer<dyn Inner> {
+    o
+}
+
+pub type AssocTy = <() as Base>::Type<dyn Inner>;

tests/rustdoc/inline_cross/dyn_trait.rs

@@ -128,3 +128,18 @@ pub use dyn_trait::BareAmbiguousBoundEarly1;
 // @has user/type.BareAmbiguousBoundStatic.html
 // @has - '//*[@class="rust item-decl"]//code' "dyn AmbiguousBoundTrait<'o, 'o> + 'static;"
 pub use dyn_trait::BareAmbiguousBoundStatic;
+
+// Regression test for issue #115179:
+
+// @has user/type.NestedTraitObjects.html
+// @has - '//*[@class="rust item-decl"]//code' "dyn Outer<dyn Inner>;"
+pub use dyn_trait::NestedTraitObjects;
+
+// @has user/fn.apit_rpit.html
+// @has - '//pre[@class="rust item-decl"]' \
+//     "apit_rpit(o: impl Outer<dyn Inner>) -> impl Outer<dyn Inner>"
+pub use dyn_trait::apit_rpit;
+
+// @has user/type.AssocTy.html
+// @has - '//*[@class="rust item-decl"]//code' "<() as Base>::Type<dyn Inner>"
+pub use dyn_trait::AssocTy;