From f708d6de79a3e17074d03a641633e2f12972dc1a Mon Sep 17 00:00:00 2001
From: Michal Piotrowski <practicalrs.com@gmail.com>
Date: Mon, 14 Oct 2024 15:37:59 +0200
Subject: [PATCH 01/10] Fix match_same_arms in stable_mir

---
 compiler/stable_mir/src/mir/pretty.rs | 10 +++-----
 compiler/stable_mir/src/mir/visit.rs  | 36 ++++++++++-----------------
 compiler/stable_mir/src/visitor.rs    | 16 ++++++------
 3 files changed, 24 insertions(+), 38 deletions(-)

diff --git a/compiler/stable_mir/src/mir/pretty.rs b/compiler/stable_mir/src/mir/pretty.rs
index 74081af1d86d0..d71d96804f3ea 100644
--- a/compiler/stable_mir/src/mir/pretty.rs
+++ b/compiler/stable_mir/src/mir/pretty.rs
@@ -189,7 +189,9 @@ fn pretty_terminator_head<W: Write>(writer: &mut W, terminator: &TerminatorKind)
 fn pretty_successor_labels(terminator: &TerminatorKind) -> Vec<String> {
     use self::TerminatorKind::*;
     match terminator {
-        Resume | Abort | Return | Unreachable => vec![],
+        Call { target: None, unwind: UnwindAction::Cleanup(_), .. }
+        | InlineAsm { destination: None, .. } => vec!["unwind".into()],
+        Resume | Abort | Return | Unreachable | Call { target: None, unwind: _, .. } => vec![],
         Goto { .. } => vec!["".to_string()],
         SwitchInt { targets, .. } => targets
             .branches()
@@ -197,19 +199,15 @@ fn pretty_successor_labels(terminator: &TerminatorKind) -> Vec<String> {
             .chain(iter::once("otherwise".into()))
             .collect(),
         Drop { unwind: UnwindAction::Cleanup(_), .. } => vec!["return".into(), "unwind".into()],
-        Drop { unwind: _, .. } => vec!["return".into()],
         Call { target: Some(_), unwind: UnwindAction::Cleanup(_), .. } => {
             vec!["return".into(), "unwind".into()]
         }
-        Call { target: Some(_), unwind: _, .. } => vec!["return".into()],
-        Call { target: None, unwind: UnwindAction::Cleanup(_), .. } => vec!["unwind".into()],
-        Call { target: None, unwind: _, .. } => vec![],
+        Drop { unwind: _, .. } | Call { target: Some(_), unwind: _, .. } => vec!["return".into()],
         Assert { unwind: UnwindAction::Cleanup(_), .. } => {
             vec!["success".into(), "unwind".into()]
         }
         Assert { unwind: _, .. } => vec!["success".into()],
         InlineAsm { destination: Some(_), .. } => vec!["goto".into(), "unwind".into()],
-        InlineAsm { destination: None, .. } => vec!["unwind".into()],
     }
 }
 
diff --git a/compiler/stable_mir/src/mir/visit.rs b/compiler/stable_mir/src/mir/visit.rs
index e2d1ff7fdd3a4..08fcfa01a06c1 100644
--- a/compiler/stable_mir/src/mir/visit.rs
+++ b/compiler/stable_mir/src/mir/visit.rs
@@ -194,27 +194,17 @@ pub trait MirVisitor {
                 self.visit_place(place, PlaceContext::MUTATING, location);
                 self.visit_rvalue(rvalue, location);
             }
-            StatementKind::FakeRead(_, place) => {
+            StatementKind::FakeRead(_, place) | StatementKind::PlaceMention(place) => {
                 self.visit_place(place, PlaceContext::NON_MUTATING, location);
             }
-            StatementKind::SetDiscriminant { place, .. } => {
+            StatementKind::SetDiscriminant { place, .. }
+            | StatementKind::Deinit(place)
+            | StatementKind::Retag(_, place) => {
                 self.visit_place(place, PlaceContext::MUTATING, location);
             }
-            StatementKind::Deinit(place) => {
-                self.visit_place(place, PlaceContext::MUTATING, location);
-            }
-            StatementKind::StorageLive(local) => {
-                self.visit_local(local, PlaceContext::NON_USE, location);
-            }
-            StatementKind::StorageDead(local) => {
+            StatementKind::StorageLive(local) | StatementKind::StorageDead(local) => {
                 self.visit_local(local, PlaceContext::NON_USE, location);
             }
-            StatementKind::Retag(_, place) => {
-                self.visit_place(place, PlaceContext::MUTATING, location);
-            }
-            StatementKind::PlaceMention(place) => {
-                self.visit_place(place, PlaceContext::NON_MUTATING, location);
-            }
             StatementKind::AscribeUserType { place, projections, variance: _ } => {
                 self.visit_place(place, PlaceContext::NON_USE, location);
                 self.visit_user_type_projection(projections);
@@ -234,8 +224,7 @@ pub trait MirVisitor {
                     self.visit_operand(count, location);
                 }
             },
-            StatementKind::ConstEvalCounter => {}
-            StatementKind::Nop => {}
+            StatementKind::ConstEvalCounter | StatementKind::Nop => {}
         }
     }
 
@@ -304,14 +293,15 @@ pub trait MirVisitor {
         location: Location,
     ) {
         match elem {
-            ProjectionElem::Deref => {}
+            ProjectionElem::Downcast(_idx) => {}
+            ProjectionElem::ConstantIndex { offset: _, min_length: _, from_end: _ }
+            | ProjectionElem::Deref
+            | ProjectionElem::Subslice { from: _, to: _, from_end: _ } => {}
             ProjectionElem::Field(_idx, ty) => self.visit_ty(ty, location),
             ProjectionElem::Index(local) => self.visit_local(local, ptx, location),
-            ProjectionElem::ConstantIndex { offset: _, min_length: _, from_end: _ } => {}
-            ProjectionElem::Subslice { from: _, to: _, from_end: _ } => {}
-            ProjectionElem::Downcast(_idx) => {}
-            ProjectionElem::OpaqueCast(ty) => self.visit_ty(ty, location),
-            ProjectionElem::Subtype(ty) => self.visit_ty(ty, location),
+            ProjectionElem::OpaqueCast(ty) | ProjectionElem::Subtype(ty) => {
+                self.visit_ty(ty, location)
+            }
         }
     }
 
diff --git a/compiler/stable_mir/src/visitor.rs b/compiler/stable_mir/src/visitor.rs
index 3c769b2d37cfc..48260285408c7 100644
--- a/compiler/stable_mir/src/visitor.rs
+++ b/compiler/stable_mir/src/visitor.rs
@@ -35,8 +35,7 @@ impl Visitable for Ty {
         match self.kind() {
             super::ty::TyKind::RigidTy(ty) => ty.visit(visitor)?,
             super::ty::TyKind::Alias(_, alias) => alias.args.visit(visitor)?,
-            super::ty::TyKind::Param(_) => {}
-            super::ty::TyKind::Bound(_, _) => {}
+            super::ty::TyKind::Param(_) | super::ty::TyKind::Bound(_, _) => {}
         }
         ControlFlow::Continue(())
     }
@@ -48,8 +47,7 @@ impl Visitable for TyConst {
     }
     fn super_visit<V: Visitor>(&self, visitor: &mut V) -> ControlFlow<V::Break> {
         match &self.kind {
-            crate::ty::TyConstKind::Param(_) => {}
-            crate::ty::TyConstKind::Bound(_, _) => {}
+            crate::ty::TyConstKind::Param(_) | crate::ty::TyConstKind::Bound(_, _) => {}
             crate::ty::TyConstKind::Unevaluated(_, args) => args.visit(visitor)?,
             crate::ty::TyConstKind::Value(ty, alloc) => {
                 alloc.visit(visitor)?;
@@ -166,17 +164,17 @@ impl Visitable for RigidTy {
                 reg.visit(visitor);
                 ty.visit(visitor)
             }
-            RigidTy::FnDef(_, args) => args.visit(visitor),
+            RigidTy::Adt(_, args)
+            | RigidTy::Closure(_, args)
+            | RigidTy::Coroutine(_, args, _)
+            | RigidTy::CoroutineWitness(_, args)
+            | RigidTy::FnDef(_, args) => args.visit(visitor),
             RigidTy::FnPtr(sig) => sig.visit(visitor),
-            RigidTy::Closure(_, args) => args.visit(visitor),
-            RigidTy::Coroutine(_, args, _) => args.visit(visitor),
-            RigidTy::CoroutineWitness(_, args) => args.visit(visitor),
             RigidTy::Dynamic(pred, r, _) => {
                 pred.visit(visitor)?;
                 r.visit(visitor)
             }
             RigidTy::Tuple(fields) => fields.visit(visitor),
-            RigidTy::Adt(_, args) => args.visit(visitor),
         }
     }
 }

From 373142aaa1e64f8a1e9071deaf0675c181ca3b47 Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Mon, 14 Oct 2024 17:15:53 -0400
Subject: [PATCH 02/10] Mark LazyCell::into_inner unstably const

Other cell `into_inner` functions are const and there shouldn't be any
problem here. Make the unstable `LazyCell::into_inner` const under the
same gate as its stability (`lazy_cell_into_inner`).

Tracking issue: https://github.com/rust-lang/rust/issues/125623
---
 library/core/src/cell/lazy.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/core/src/cell/lazy.rs b/library/core/src/cell/lazy.rs
index 5bc13779af9f8..d323fbeac9c10 100644
--- a/library/core/src/cell/lazy.rs
+++ b/library/core/src/cell/lazy.rs
@@ -79,7 +79,7 @@ impl<T, F: FnOnce() -> T> LazyCell<T, F> {
     /// assert_eq!(LazyCell::into_inner(lazy).ok(), Some("HELLO, WORLD!".to_string()));
     /// ```
     #[unstable(feature = "lazy_cell_into_inner", issue = "125623")]
-    pub fn into_inner(this: Self) -> Result<T, F> {
+    pub const fn into_inner(this: Self) -> Result<T, F> {
         match this.state.into_inner() {
             State::Init(data) => Ok(data),
             State::Uninit(f) => Err(f),
@@ -306,6 +306,6 @@ impl<T: fmt::Debug, F> fmt::Debug for LazyCell<T, F> {
 
 #[cold]
 #[inline(never)]
-fn panic_poisoned() -> ! {
+const fn panic_poisoned() -> ! {
     panic!("LazyCell instance has previously been poisoned")
 }

From 5d178e1d4da25110e72b297caaef6489e920f04f Mon Sep 17 00:00:00 2001
From: c6c7 <github@chcl.io>
Date: Mon, 14 Oct 2024 12:38:49 -0400
Subject: [PATCH 03/10] Make fuchsia-test-runner.py compatible with new JSON
 output from llvm-readelf

[A recent commit in LLVM](https://github.com/llvm/llvm-project/commit/ab930ee7cad8b8bf7968bb8d0c0d72524e2313c4) modified the JSON output of LLVM. The LLVM change renamed "Notes" to "NoteSections" and inserted a new "Notes" key nested under each "NoteSection".

This change shores up exceptions around reading the JSON output of llvm-readelf and reads from "NoteSections" instead of the non-existent "Notes".
---
 src/ci/docker/scripts/fuchsia-test-runner.py | 42 +++++++++++++++-----
 1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/src/ci/docker/scripts/fuchsia-test-runner.py b/src/ci/docker/scripts/fuchsia-test-runner.py
index a5458b8645d7f..1aa9a4a1794fa 100755
--- a/src/ci/docker/scripts/fuchsia-test-runner.py
+++ b/src/ci/docker/scripts/fuchsia-test-runner.py
@@ -193,18 +193,38 @@ def build_id(self, binary):
             stderr=subprocess.STDOUT,
         )
         if process.returncode:
-            self.env_logger.error(
-                f"llvm-readelf failed for binary {binary} with output {process.stdout}"
+            e = f"llvm-readelf failed for binary {binary} with output {process.stdout}"
+            self.env_logger.error(e)
+            raise Exception(e)
+
+        try:
+            elf_output = json.loads(process.stdout)
+        except Exception as e:
+            e.add_note(f"Failed to read JSON from llvm-readelf for binary {binary}")
+            e.add_note(f"stdout: {process.stdout}")
+            raise
+
+        try:
+            note_sections = elf_output[0]["NoteSections"]
+        except Exception as e:
+            e.add_note(
+                f'Failed to read "NoteSections" from llvm-readelf for binary {binary}'
             )
-            raise Exception(f"Unreadable build-id for binary {binary}")
-        data = json.loads(process.stdout)
-        if len(data) != 1:
-            raise Exception(f"Unreadable output from llvm-readelf for binary {binary}")
-        notes = data[0]["Notes"]
-        for note in notes:
-            note_section = note["NoteSection"]
-            if note_section["Name"] == ".note.gnu.build-id":
-                return note_section["Note"]["Build ID"]
+            e.add_note(f"elf_output: {elf_output}")
+            raise
+
+        for entry in note_sections:
+            try:
+                note_section = entry["NoteSection"]
+                if note_section["Name"] == ".note.gnu.build-id":
+                    return note_section["Notes"][0]["Build ID"]
+            except Exception as e:
+                e.add_note(
+                    f'Failed to read ".note.gnu.build-id" from NoteSections \
+                        entry in llvm-readelf for binary {binary}'
+                )
+                e.add_note(f"NoteSections: {note_sections}")
+                raise
         raise Exception(f"Build ID not found for binary {binary}")
 
     def generate_buildid_dir(

From 937d13b8efc43f3f2e93f81360565d82f243ce15 Mon Sep 17 00:00:00 2001
From: Slanterns <slanterns.w@gmail.com>
Date: Wed, 16 Oct 2024 00:22:05 +0800
Subject: [PATCH 04/10] relax a memory order in `once_box`

---
 library/std/src/sys/sync/once_box.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/std/src/sys/sync/once_box.rs b/library/std/src/sys/sync/once_box.rs
index 1422b5a172162..9d24db2245a0b 100644
--- a/library/std/src/sys/sync/once_box.rs
+++ b/library/std/src/sys/sync/once_box.rs
@@ -8,7 +8,7 @@
 use crate::mem::replace;
 use crate::ptr::null_mut;
 use crate::sync::atomic::AtomicPtr;
-use crate::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed};
+use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
 
 pub(crate) struct OnceBox<T> {
     ptr: AtomicPtr<T>,
@@ -60,7 +60,7 @@ impl<T> OnceBox<T> {
     #[cold]
     fn initialize(&self, f: impl FnOnce() -> Box<T>) -> &T {
         let new_ptr = Box::into_raw(f());
-        match self.ptr.compare_exchange(null_mut(), new_ptr, AcqRel, Acquire) {
+        match self.ptr.compare_exchange(null_mut(), new_ptr, Release, Acquire) {
             Ok(_) => unsafe { &*new_ptr },
             Err(ptr) => {
                 // Lost the race to another thread.

From 68885216b63f6e75e50b4c0f3c7250ca4ac7afda Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 15 Oct 2024 14:58:41 -0400
Subject: [PATCH 05/10] Don't report bivariance error when nesting a struct
 with field errors into another struct

---
 .../rustc_hir_analysis/src/check/wfcheck.rs   | 60 +++++++++++++++----
 .../type-resolve-error-two-structs-deep.rs    | 13 ++++
 ...type-resolve-error-two-structs-deep.stderr |  9 +++
 3 files changed, 72 insertions(+), 10 deletions(-)
 create mode 100644 tests/ui/variance/type-resolve-error-two-structs-deep.rs
 create mode 100644 tests/ui/variance/type-resolve-error-two-structs-deep.stderr

diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 607068f162aa3..f788456d4e9eb 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -1875,24 +1875,15 @@ fn check_variances_for_type_defn<'tcx>(
     item: &'tcx hir::Item<'tcx>,
     hir_generics: &hir::Generics<'tcx>,
 ) {
-    let identity_args = ty::GenericArgs::identity_for_item(tcx, item.owner_id);
-
     match item.kind {
         ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) => {
-            for field in tcx.adt_def(item.owner_id).all_fields() {
-                if field.ty(tcx, identity_args).references_error() {
-                    return;
-                }
-            }
+            // Ok
         }
         ItemKind::TyAlias(..) => {
             assert!(
                 tcx.type_alias_is_lazy(item.owner_id),
                 "should not be computing variance of non-weak type alias"
             );
-            if tcx.type_of(item.owner_id).skip_binder().references_error() {
-                return;
-            }
         }
         kind => span_bug!(item.span, "cannot compute the variances of {kind:?}"),
     }
@@ -1955,6 +1946,15 @@ fn check_variances_for_type_defn<'tcx>(
             continue;
         }
 
+        // Look for `ErrorGuaranteed` deeply within this type.
+        if let ControlFlow::Break(ErrorGuaranteed { .. }) = tcx
+            .type_of(item.owner_id)
+            .instantiate_identity()
+            .visit_with(&mut HasErrorDeep { tcx, seen: Default::default() })
+        {
+            continue;
+        }
+
         match hir_param.name {
             hir::ParamName::Error => {}
             _ => {
@@ -1965,6 +1965,46 @@ fn check_variances_for_type_defn<'tcx>(
     }
 }
 
+/// Look for `ErrorGuaranteed` deeply within structs' (unsubstituted) fields.
+struct HasErrorDeep<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    seen: FxHashSet<DefId>,
+}
+impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for HasErrorDeep<'tcx> {
+    type Result = ControlFlow<ErrorGuaranteed>;
+
+    fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
+        match *ty.kind() {
+            ty::Adt(def, _) => {
+                if self.seen.insert(def.did()) {
+                    for field in def.all_fields() {
+                        self.tcx.type_of(field.did).instantiate_identity().visit_with(self)?;
+                    }
+                }
+            }
+            ty::Error(guar) => return ControlFlow::Break(guar),
+            _ => {}
+        }
+        ty.super_visit_with(self)
+    }
+
+    fn visit_region(&mut self, r: ty::Region<'tcx>) -> Self::Result {
+        if let Err(guar) = r.error_reported() {
+            ControlFlow::Break(guar)
+        } else {
+            ControlFlow::Continue(())
+        }
+    }
+
+    fn visit_const(&mut self, c: ty::Const<'tcx>) -> Self::Result {
+        if let Err(guar) = c.error_reported() {
+            ControlFlow::Break(guar)
+        } else {
+            ControlFlow::Continue(())
+        }
+    }
+}
+
 fn report_bivariance<'tcx>(
     tcx: TyCtxt<'tcx>,
     param: &'tcx hir::GenericParam<'tcx>,
diff --git a/tests/ui/variance/type-resolve-error-two-structs-deep.rs b/tests/ui/variance/type-resolve-error-two-structs-deep.rs
new file mode 100644
index 0000000000000..47ec532ab9681
--- /dev/null
+++ b/tests/ui/variance/type-resolve-error-two-structs-deep.rs
@@ -0,0 +1,13 @@
+// Make sure we don't report bivariance errors when nesting structs w/ unresolved
+// fields into *other* structs.
+
+struct Hello<'a> {
+    missing: Missing<'a>,
+    //~^ ERROR cannot find type `Missing` in this scope
+}
+
+struct Other<'a> {
+    hello: Hello<'a>,
+}
+
+fn main() {}
diff --git a/tests/ui/variance/type-resolve-error-two-structs-deep.stderr b/tests/ui/variance/type-resolve-error-two-structs-deep.stderr
new file mode 100644
index 0000000000000..3458d924bb153
--- /dev/null
+++ b/tests/ui/variance/type-resolve-error-two-structs-deep.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+  --> $DIR/type-resolve-error-two-structs-deep.rs:5:14
+   |
+LL |     missing: Missing<'a>,
+   |              ^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0412`.

From e9853961452b56997cc127b51308879b9cd09482 Mon Sep 17 00:00:00 2001
From: Matthew Maurer <mmaurer@google.com>
Date: Tue, 15 Oct 2024 20:56:20 +0000
Subject: [PATCH 06/10] llvm: Match aarch64 data layout to new LLVM layout

LLVM has added 3 new address spaces to support special Windows use
cases. These shouldn't trouble us for now, but LLVM requires matching
data layouts.

See llvm/llvm-project#111879 for details
---
 compiler/rustc_codegen_llvm/src/context.rs             | 10 ++++++++++
 .../src/spec/targets/aarch64_apple_darwin.rs           |  3 ++-
 .../rustc_target/src/spec/targets/aarch64_apple_ios.rs |  3 ++-
 .../src/spec/targets/aarch64_apple_ios_macabi.rs       |  3 ++-
 .../src/spec/targets/aarch64_apple_ios_sim.rs          |  3 ++-
 .../src/spec/targets/aarch64_apple_tvos.rs             |  3 ++-
 .../src/spec/targets/aarch64_apple_tvos_sim.rs         |  3 ++-
 .../src/spec/targets/aarch64_apple_visionos.rs         |  3 ++-
 .../src/spec/targets/aarch64_apple_visionos_sim.rs     |  3 ++-
 .../src/spec/targets/aarch64_apple_watchos.rs          |  3 ++-
 .../src/spec/targets/aarch64_apple_watchos_sim.rs      |  3 ++-
 .../src/spec/targets/aarch64_kmc_solid_asp3.rs         |  2 +-
 .../src/spec/targets/aarch64_linux_android.rs          |  2 +-
 .../targets/aarch64_nintendo_switch_freestanding.rs    |  2 +-
 .../src/spec/targets/aarch64_pc_windows_gnullvm.rs     |  4 +++-
 .../src/spec/targets/aarch64_pc_windows_msvc.rs        |  4 +++-
 .../src/spec/targets/aarch64_unknown_freebsd.rs        |  2 +-
 .../src/spec/targets/aarch64_unknown_fuchsia.rs        |  2 +-
 .../src/spec/targets/aarch64_unknown_hermit.rs         |  2 +-
 .../src/spec/targets/aarch64_unknown_illumos.rs        |  2 +-
 .../src/spec/targets/aarch64_unknown_linux_gnu.rs      |  2 +-
 .../src/spec/targets/aarch64_unknown_linux_musl.rs     |  2 +-
 .../src/spec/targets/aarch64_unknown_linux_ohos.rs     |  2 +-
 .../src/spec/targets/aarch64_unknown_netbsd.rs         |  2 +-
 .../src/spec/targets/aarch64_unknown_none.rs           |  2 +-
 .../src/spec/targets/aarch64_unknown_none_softfloat.rs |  2 +-
 .../src/spec/targets/aarch64_unknown_nto_qnx700.rs     |  2 +-
 .../src/spec/targets/aarch64_unknown_openbsd.rs        |  2 +-
 .../src/spec/targets/aarch64_unknown_redox.rs          |  2 +-
 .../src/spec/targets/aarch64_unknown_teeos.rs          |  2 +-
 .../src/spec/targets/aarch64_unknown_trusty.rs         |  2 +-
 .../src/spec/targets/aarch64_unknown_uefi.rs           |  4 +++-
 .../src/spec/targets/aarch64_uwp_windows_msvc.rs       |  4 +++-
 .../src/spec/targets/aarch64_wrs_vxworks.rs            |  2 +-
 .../src/spec/targets/arm64_32_apple_watchos.rs         |  3 ++-
 .../src/spec/targets/arm64e_apple_darwin.rs            |  3 ++-
 .../rustc_target/src/spec/targets/arm64e_apple_ios.rs  |  3 ++-
 .../rustc_target/src/spec/targets/arm64e_apple_tvos.rs |  3 ++-
 .../src/spec/targets/arm64ec_pc_windows_msvc.rs        |  4 +++-
 39 files changed, 72 insertions(+), 38 deletions(-)

diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index c836dd5473f3c..2f830d6f941e7 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -138,6 +138,16 @@ pub(crate) unsafe fn create_module<'ll>(
         }
     }
 
+    if llvm_version < (20, 0, 0) {
+        if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
+            // LLVM 20 defines three additional address spaces for alternate
+            // pointer kinds used in Windows.
+            // See https://github.com/llvm/llvm-project/pull/111879
+            target_data_layout =
+                target_data_layout.replace("-p270:32:32-p271:32:32-p272:64:64", "");
+        }
+    }
+
     // Ensure the data-layout values hardcoded remain the defaults.
     {
         let tm = crate::back::write::create_informational_target_machine(tcx.sess, false);
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_darwin.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_darwin.rs
index e6ce50a005f7d..adee6f5fe9943 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_darwin.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_darwin.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             mcount: "\u{1}mcount".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios.rs
index 78441ede3337e..efc42b909e4e1 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_macabi.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_macabi.rs
index 857abd21faf68..be503d18bf151 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_macabi.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_macabi.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a12".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_sim.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_sim.rs
index cbc8b7cd95e45..04bbee45cd322 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_sim.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_ios_sim.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos.rs
index f5176d35f809f..fa0bc130e1c79 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos_sim.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos_sim.rs
index d673851414560..428045da49301 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos_sim.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_tvos_sim.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs
index dc5dac4fd8f2e..62d6ffbd34f08 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a16".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs
index e9fe786f65ec5..a66c4f6e96bd1 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a16".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos.rs
index 4f5ce2f12e73c..abd924b5934af 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+v8a,+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos_sim.rs b/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos_sim.rs
index 952c98c324fa7..ba85647fddccb 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos_sim.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_apple_watchos_sim.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_kmc_solid_asp3.rs b/compiler/rustc_target/src/spec/targets/aarch64_kmc_solid_asp3.rs
index 97ce53b2d8fde..58fc703946e5d 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_kmc_solid_asp3.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_kmc_solid_asp3.rs
@@ -11,7 +11,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             linker: Some("aarch64-kmc-elf-gcc".into()),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_linux_android.rs b/compiler/rustc_target/src/spec/targets/aarch64_linux_android.rs
index a8ef5544a243e..a021d317cc83a 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_linux_android.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_linux_android.rs
@@ -13,7 +13,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             max_atomic_width: Some(128),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_nintendo_switch_freestanding.rs b/compiler/rustc_target/src/spec/targets/aarch64_nintendo_switch_freestanding.rs
index 1f1cd96632675..6ac69e0f57f3b 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_nintendo_switch_freestanding.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_nintendo_switch_freestanding.rs
@@ -15,7 +15,7 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_gnullvm.rs b/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_gnullvm.rs
index 7a56809dcfc70..8b96f589c74d6 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_gnullvm.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_gnullvm.rs
@@ -15,7 +15,9 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32"
+                .into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_msvc.rs b/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_msvc.rs
index e1133a4ce051c..14ce5edd2f3c3 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_msvc.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_pc_windows_msvc.rs
@@ -14,7 +14,9 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32"
+                .into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_freebsd.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_freebsd.rs
index 2ca2f403e1773..dd90161f4408a 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_freebsd.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_freebsd.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_fuchsia.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_fuchsia.rs
index 26a736a271266..df13d52a22365 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_fuchsia.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_fuchsia.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_hermit.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_hermit.rs
index 3989cc13fba50..459e888eb9439 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_hermit.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_hermit.rs
@@ -11,7 +11,7 @@ pub(crate) fn target() -> Target {
         },
         pointer_width: 64,
         arch: "aarch64".into(),
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         options: TargetOptions {
             features: "+v8a,+strict-align,+neon,+fp-armv8".into(),
             max_atomic_width: Some(128),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_illumos.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_illumos.rs
index b76f10b8efdfa..699376a7928b4 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_illumos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_illumos.rs
@@ -18,7 +18,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_gnu.rs
index 96c25af0a7fc0..18711cb399d73 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_gnu.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a,+outline-atomics".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs
index 197ff2d74e5e5..bb65048a56d66 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs
@@ -21,7 +21,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions { mcount: "\u{1}_mcount".into(), ..base },
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs
index 9d5bce053500c..22b3a5f88426d 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs
@@ -13,7 +13,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+reserve-x18".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_netbsd.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_netbsd.rs
index d1769d1476ccf..0ec76e4b42fd3 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_netbsd.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_netbsd.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_none.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_none.rs
index d124f8a3d2974..05fe32734a7e4 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_none.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_none.rs
@@ -37,7 +37,7 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: opts,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_none_softfloat.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_none_softfloat.rs
index 7933041b584ec..d6b77ffd091a9 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_none_softfloat.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_none_softfloat.rs
@@ -32,7 +32,7 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: opts,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_nto_qnx700.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_nto_qnx700.rs
index 6c061112b1667..441ed7cf1535e 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_nto_qnx700.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_nto_qnx700.rs
@@ -22,7 +22,7 @@ pub(crate) fn target() -> Target {
         // i128:128  = 128-bit-integer, minimum_alignment=128, preferred_alignment=128
         // n32:64    = 32 and 64 are native integer widths; Elements of this set are considered to support most general arithmetic operations efficiently.
         // S128      = 128 bits are the natural alignment of the stack in bits.
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_openbsd.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_openbsd.rs
index 31c8daa98b069..0fcf5c34bb0ee 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_openbsd.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_openbsd.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_redox.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_redox.rs
index 6bd8c306abb46..7ff99c574ad82 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_redox.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_redox.rs
@@ -15,7 +15,7 @@ pub(crate) fn target() -> Target {
             std: None, // ?
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_teeos.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_teeos.rs
index 4bffef4758d1b..fb8b59f77291a 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_teeos.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_teeos.rs
@@ -15,7 +15,7 @@ pub(crate) fn target() -> Target {
             std: None, // ?
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs
index 69ab992e12ca1..cebd8ff2f6848 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs
@@ -12,7 +12,7 @@ pub(crate) fn target() -> Target {
             std: Some(false),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+neon,+fp-armv8,+reserve-x18".into(),
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_uefi.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_uefi.rs
index bde1ce95b3f98..9656024ddaa1f 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_uefi.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_uefi.rs
@@ -19,7 +19,9 @@ pub(crate) fn target() -> Target {
             std: None, // ?
         },
         pointer_width: 64,
-        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32"
+                .into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_uwp_windows_msvc.rs b/compiler/rustc_target/src/spec/targets/aarch64_uwp_windows_msvc.rs
index c916aa6b23cfe..3d7c026980807 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_uwp_windows_msvc.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_uwp_windows_msvc.rs
@@ -14,7 +14,9 @@ pub(crate) fn target() -> Target {
             std: None, // ?
         },
         pointer_width: 64,
-        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32"
+                .into(),
         arch: "aarch64".into(),
         options: base,
     }
diff --git a/compiler/rustc_target/src/spec/targets/aarch64_wrs_vxworks.rs b/compiler/rustc_target/src/spec/targets/aarch64_wrs_vxworks.rs
index dd5298944e0d1..d5e78d0307606 100644
--- a/compiler/rustc_target/src/spec/targets/aarch64_wrs_vxworks.rs
+++ b/compiler/rustc_target/src/spec/targets/aarch64_wrs_vxworks.rs
@@ -10,7 +10,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: "aarch64".into(),
         options: TargetOptions {
             features: "+v8a".into(),
diff --git a/compiler/rustc_target/src/spec/targets/arm64_32_apple_watchos.rs b/compiler/rustc_target/src/spec/targets/arm64_32_apple_watchos.rs
index 4f7a1857e76ab..a5a6f772ac840 100644
--- a/compiler/rustc_target/src/spec/targets/arm64_32_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/targets/arm64_32_apple_watchos.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 32,
-        data_layout: "e-m:o-p:32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:o-p:32:32-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch,
         options: TargetOptions {
             features: "+v8a,+neon,+fp-armv8,+apple-a7".into(),
diff --git a/compiler/rustc_target/src/spec/targets/arm64e_apple_darwin.rs b/compiler/rustc_target/src/spec/targets/arm64e_apple_darwin.rs
index 04906fb046097..744d95445b8e8 100644
--- a/compiler/rustc_target/src/spec/targets/arm64e_apple_darwin.rs
+++ b/compiler/rustc_target/src/spec/targets/arm64e_apple_darwin.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             mcount: "\u{1}mcount".into(),
diff --git a/compiler/rustc_target/src/spec/targets/arm64e_apple_ios.rs b/compiler/rustc_target/src/spec/targets/arm64e_apple_ios.rs
index 3264669c169f0..dace11dae24db 100644
--- a/compiler/rustc_target/src/spec/targets/arm64e_apple_ios.rs
+++ b/compiler/rustc_target/src/spec/targets/arm64e_apple_ios.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a12,+v8.3a,+pauth".into(),
diff --git a/compiler/rustc_target/src/spec/targets/arm64e_apple_tvos.rs b/compiler/rustc_target/src/spec/targets/arm64e_apple_tvos.rs
index 4c231cb519c0e..2ccdc76c52e6c 100644
--- a/compiler/rustc_target/src/spec/targets/arm64e_apple_tvos.rs
+++ b/compiler/rustc_target/src/spec/targets/arm64e_apple_tvos.rs
@@ -12,7 +12,8 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+            .into(),
         arch,
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a12,+v8.3a,+pauth".into(),
diff --git a/compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs b/compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs
index a6744b95a3eb7..03c96fbfdb0c3 100644
--- a/compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs
+++ b/compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs
@@ -18,7 +18,9 @@ pub(crate) fn target() -> Target {
             std: None, // ?
         },
         pointer_width: 64,
-        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        data_layout:
+            "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32"
+                .into(),
         arch: "arm64ec".into(),
         options: base,
     }

From 4cf0475eeb6fb3aca3b67cd16127d825709a0bb4 Mon Sep 17 00:00:00 2001
From: Zalathar <Zalathar@users.noreply.github.com>
Date: Wed, 16 Oct 2024 12:16:17 +1100
Subject: [PATCH 07/10] Fix unnecessary nesting in run-make test output
 directories

---
 src/tools/compiletest/src/runtest/run_make.rs | 6 +++++-
 tests/run-make/README.md                      | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/tools/compiletest/src/runtest/run_make.rs b/src/tools/compiletest/src/runtest/run_make.rs
index 75fe6a6baafa1..f8ffd0fbe3f70 100644
--- a/src/tools/compiletest/src/runtest/run_make.rs
+++ b/src/tools/compiletest/src/runtest/run_make.rs
@@ -22,6 +22,10 @@ impl TestCx<'_> {
         let src_root = self.config.src_base.parent().unwrap().parent().unwrap();
         let src_root = cwd.join(&src_root);
 
+        // FIXME(Zalathar): This should probably be `output_base_dir` to avoid
+        // an unnecessary extra subdirectory, but since legacy Makefile tests
+        // are hopefully going away, it seems safer to leave this perilous code
+        // as-is until it can all be deleted.
         let tmpdir = cwd.join(self.output_base_name());
         if tmpdir.exists() {
             self.aggressive_rm_rf(&tmpdir).unwrap();
@@ -213,7 +217,7 @@ impl TestCx<'_> {
         // `rmake_out/` directory.
         //
         // This setup intentionally diverges from legacy Makefile run-make tests.
-        let base_dir = self.output_base_name();
+        let base_dir = self.output_base_dir();
         if base_dir.exists() {
             self.aggressive_rm_rf(&base_dir).unwrap();
         }
diff --git a/tests/run-make/README.md b/tests/run-make/README.md
index 9e1eaa881c946..4035990347389 100644
--- a/tests/run-make/README.md
+++ b/tests/run-make/README.md
@@ -29,7 +29,7 @@ The setup for the `rmake.rs` version is a 3-stage process:
    structure within `build/<target>/test/run-make/`
 
    ```
-   <test-name>/<test-name>/
+   <test-name>/
        rmake.exe              # recipe binary
        rmake_out/             # sources from test sources copied over
    ```

From 69faeafd0cac0f503f75a994f68f3e42af568046 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <39484203+jieyouxu@users.noreply.github.com>
Date: Wed, 16 Oct 2024 10:40:29 +0800
Subject: [PATCH 08/10] mailmap: add entry for my dev-desktop setup

---
 .mailmap | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.mailmap b/.mailmap
index dc5bfe6d5fc76..bdc34c52aa768 100644
--- a/.mailmap
+++ b/.mailmap
@@ -280,6 +280,7 @@ Jerry Hardee <hardeejj9@gmail.com>
 Jesús Rubio <jesusprubio@gmail.com>
 Jethro Beekman <github@jbeekman.nl>
 Jian Zeng <knight42@mail.ustc.edu.cn>
+Jieyou Xu <jieyouxu@outlook.com> <39484203+jieyouxu@users.noreply.github.com>
 Jihyun Yu <j.yu@navercorp.com> <yjh0502@gmail.com>
 Jihyun Yu <j.yu@navercorp.com> jihyun <jihyun@nablecomm.com>
 Jihyun Yu <j.yu@navercorp.com> Jihyun Yu <jihyun@nclab.kaist.ac.kr>

From 0804d1bc27bd9b64c1302851f047316f086a0d1a Mon Sep 17 00:00:00 2001
From: Juniper Tyree <50025784+juntyr@users.noreply.github.com>
Date: Sat, 12 Oct 2024 08:03:02 +0300
Subject: [PATCH 09/10] Add wasm32-unknown-emscripten platform support document

Co-authored-by: Hood Chatham <roberthoodchatham@gmail.com>
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
Co-authored-by: Kleis Auke Wolthuizen <github@kleisauke.nl>
---
 src/doc/rustc/src/SUMMARY.md                  |   1 +
 src/doc/rustc/src/platform-support.md         |   2 +-
 .../wasm32-unknown-emscripten.md              | 168 ++++++++++++++++++
 .../wasm32-unknown-unknown.md                 |   4 +-
 4 files changed, 172 insertions(+), 3 deletions(-)
 create mode 100644 src/doc/rustc/src/platform-support/wasm32-unknown-emscripten.md

diff --git a/src/doc/rustc/src/SUMMARY.md b/src/doc/rustc/src/SUMMARY.md
index b1a5bd604eb32..795908b32c0ba 100644
--- a/src/doc/rustc/src/SUMMARY.md
+++ b/src/doc/rustc/src/SUMMARY.md
@@ -84,6 +84,7 @@
     - [wasm32-wasip1](platform-support/wasm32-wasip1.md)
     - [wasm32-wasip1-threads](platform-support/wasm32-wasip1-threads.md)
     - [wasm32-wasip2](platform-support/wasm32-wasip2.md)
+    - [wasm32-unknown-emscripten](platform-support/wasm32-unknown-emscripten.md)
     - [wasm32-unknown-unknown](platform-support/wasm32-unknown-unknown.md)
     - [wasm64-unknown-unknown](platform-support/wasm64-unknown-unknown.md)
     - [\*-win7-windows-msvc](platform-support/win7-windows-msvc.md)
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 0ef95ba64a1f5..022fc9da7e03a 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -190,7 +190,7 @@ target | std | notes
 [`thumbv8m.base-none-eabi`](platform-support/thumbv8m.base-none-eabi.md) | * | Bare Armv8-M Baseline
 [`thumbv8m.main-none-eabi`](platform-support/thumbv8m.main-none-eabi.md) | * | Bare Armv8-M Mainline
 [`thumbv8m.main-none-eabihf`](platform-support/thumbv8m.main-none-eabi.md) | * | Bare Armv8-M Mainline, hardfloat
-`wasm32-unknown-emscripten` | ✓ | WebAssembly via Emscripten
+[`wasm32-unknown-emscripten`](platform-support/wasm32-unknown-emscripten.md) | ✓ | WebAssembly via Emscripten
 [`wasm32-unknown-unknown`](platform-support/wasm32-unknown-unknown.md) | ✓ | WebAssembly
 `wasm32-wasi` | ✓ | WebAssembly with WASI (undergoing a [rename to `wasm32-wasip1`][wasi-rename])
 [`wasm32-wasip1`](platform-support/wasm32-wasip1.md) | ✓ | WebAssembly with WASI
diff --git a/src/doc/rustc/src/platform-support/wasm32-unknown-emscripten.md b/src/doc/rustc/src/platform-support/wasm32-unknown-emscripten.md
new file mode 100644
index 0000000000000..7a9cd4b522b9c
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/wasm32-unknown-emscripten.md
@@ -0,0 +1,168 @@
+# `wasm32-unknown-emscripten`
+
+**Tier: 2**
+
+The `wasm32-unknown-emscripten` target is a WebAssembly compilation target which
+uses the [Emscripten](https://emscripten.org/) compiler toolchain. Emscripten is
+a C/C++ toolchain designed to make it as easy as possible to port C/C++ code
+written for Linux to run on the web or in other JavaScript runtimes such as Node.
+It thus provides POSIX-compatible (musl) `libc` and `libstd` implementations and
+many Linux APIs, access to the OpenGL and SDL APIs, and the ability to run arbitrary
+JavaScript code, all based on web APIs using JS glue code. With the
+`wasm32-unknown-emscripten` target, Rust code can interoperate with Emscripten's
+ecosystem, C/C++ and JS code, and web APIs.
+
+One existing user of this target is the
+[`pyodide` project](https://pyodide.org/) which provides a Python runtime in
+WebAssembly using Emscripten and compiles Python extension modules written in Rust
+to the `wasm32-unknown-emscripten` target.
+
+If you want to generate a standalone WebAssembly binary that does not require
+access to the web APIs or the Rust standard library, the
+[`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md) target may be better
+suited for you. However, [`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md)
+does not (easily) support interop with C/C++ code. Please refer to the
+[wasm-bindgen](https://crates.io/crates/wasm-bindgen) crate in case you want to
+interoperate with JavaScript with this target.
+
+Like Emscripten, the WASI targets [`wasm32-wasip1`](./wasm32-wasip1.md) and
+[`wasm32-wasip2`](./wasm32-wasip2.md) also provide access to the host environment,
+support interop with C/C++ (and other languages), and support most of the Rust
+standard library. While the WASI targets are portable across different hosts
+(web and non-web), WASI has no standard way of accessing web APIs, whereas
+Emscripten has the ability to run arbitrary JS from WASM and access many web APIs.
+If you are only targeting the web and need to access web APIs, the
+`wasm32-unknown-emscripten` target may be preferable.
+
+## Target maintainers
+
+- Hood Chatham, https://github.com/hoodmane
+- Juniper Tyree, https://github.com/juntyr
+
+## Requirements
+
+This target is cross-compiled. The Emscripten compiler toolchain `emcc` must be
+installed to link WASM binaries for this target. You can install `emcc` using:
+
+```sh
+git clone https://github.com/emscripten-core/emsdk.git --depth 1
+./emsdk/emsdk install 3.1.68
+./emsdk/emsdk activate 3.1.68
+source ./emsdk/emsdk_env.sh
+```
+
+Please refer to <https://emscripten.org/docs/getting_started/downloads.html> for
+further details and instructions.
+
+## Building the target
+
+Building this target can be done by:
+
+* Configure the `wasm32-unknown-emscripten` target to get built.
+* Ensure the `WebAssembly` target backend is not disabled in LLVM.
+
+These are all controlled through `config.toml` options. It should be possible
+to build this target on any platform. A minimal example configuration would be:
+
+```toml
+[llvm]
+targets = "WebAssembly"
+
+[build]
+build-stage = 1
+target = ["wasm32-unknown-emscripten"]
+```
+
+## Building Rust programs
+
+Rust programs can be compiled by adding this target via rustup:
+
+```sh
+$ rustup target add wasm32-unknown-emscripten
+```
+
+and then compiling with the target:
+
+```sh
+$ rustc foo.rs --target wasm32-unknown-emscripten
+$ file foo.wasm
+```
+
+## Cross-compilation
+
+This target can be cross-compiled from any host.
+
+## Emscripten ABI Compatibility
+
+The Emscripten compiler toolchain does not follow a semantic versioning scheme
+that clearly indicates when breaking changes to the ABI can be made. Additionally,
+Emscripten offers many different ABIs even for a single version of Emscripten
+depending on the linker flags used, e.g. `-fexceptions` and `-sWASM_BIGINT`. If
+the ABIs mismatch, your code may exhibit undefined behaviour.
+
+To ensure that the ABIs of your Rust code, of the Rust standard library, and of
+other code compiled for Emscripten all match, you should rebuild the Rust standard
+library with your local Emscripten version and settings using:
+
+```sh
+cargo +nightly -Zbuild-std build
+```
+
+If you still want to use the pre-compiled `std` from rustup, you should ensure
+that your local Emscripten matches the version used by Rust and be careful about
+any `-C link-arg`s that you compiled your Rust code with.
+
+## Testing
+
+This target is not extensively tested in CI for the rust-lang/rust repository. It
+can be tested locally, for example, with:
+
+```sh
+./x.py test --target wasm32-unknown-emscripten --skip src/tools/linkchecker
+```
+
+To run these tests, both `emcc` and `node` need to be in your `$PATH`. You can
+install `node`, for example, using `nvm` by following the instructions at
+<https://github.com/nvm-sh/nvm#install--update-script>.
+
+If you need to test WebAssembly compatibility *in general*, it is recommended
+to test the [`wasm32-wasip1`](./wasm32-wasip1.md) target instead.
+
+## Conditionally compiling code
+
+It's recommended to conditionally compile code for this target with:
+
+```text
+#[cfg(target_os = "emscripten")]
+```
+
+It may sometimes be necessary to conditionally compile code for WASM targets
+which do *not* use emscripten, which can be achieved with:
+
+```text
+#[cfg(all(target_family = "wasm", not(target_os = "emscripten)))]
+```
+
+## Enabled WebAssembly features
+
+WebAssembly is an evolving standard which adds new features such as new
+instructions over time. This target's default set of supported WebAssembly
+features will additionally change over time. The `wasm32-unknown-emscripten` target
+inherits the default settings of LLVM which typically, but not necessarily, matches
+the default settings of Emscripten as well. At link time, `emcc` configures the
+linker to use Emscripten's settings.
+
+Please refer to the [`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md)
+target's documentation on which WebAssembly features Rust enables by default, how
+features can be disabled, and how Rust code can be conditionally compiled based on
+which features are enabled.
+
+Note that Rust code compiled for `wasm32-unknown-emscripten` currently enables
+`-fexceptions` (JS exceptions) by default unless the Rust code is compiled with
+`-Cpanic=abort`. `-fwasm-exceptions` (WASM exceptions) is not yet currently supported,
+see <https://github.com/rust-lang/rust/issues/112195>.
+
+Please refer to the [Emscripten ABI compatibility](#emscripten-abi-compatibility)
+section to ensure that the features that are enabled do not cause an ABI mismatch
+between your Rust code, the pre-compiled Rust standard library, and other code compiled
+for Emscripten.
diff --git a/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md b/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
index 0e06a820a22c3..48a8df0c4a866 100644
--- a/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
+++ b/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
@@ -46,8 +46,8 @@ This target currently has no equivalent in C/C++. There is no C/C++ toolchain
 for this target. While interop is theoretically possible it's recommended to
 instead use one of:
 
-* `wasm32-unknown-emscripten` - for web-based use cases the Emscripten
-  toolchain is typically chosen for running C/C++.
+* [`wasm32-unknown-emscripten`](./wasm32-unknown-emscripten.md) - for web-based
+  use cases the Emscripten toolchain is typically chosen for running C/C++.
 * [`wasm32-wasip1`](./wasm32-wasip1.md) - the wasi-sdk toolchain is used to
   compile C/C++ on this target and can interop with Rust code. WASI works on
   the web so far as there's no blocker, but an implementation of WASI APIs

From 5eb863698964b026149f4ed9f958639eb290f5b3 Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Wed, 16 Oct 2024 09:41:49 +0200
Subject: [PATCH 10/10] Handle gracefully true/false in `cfg(target(..))`
 compact

---
 compiler/rustc_attr/src/builtin.rs            | 8 +++++++-
 tests/ui/cfg/cfg-target-compact-errors.rs     | 4 ++++
 tests/ui/cfg/cfg-target-compact-errors.stderr | 8 +++++++-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index c1db4d07dfc86..bbb1749768449 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -723,7 +723,13 @@ pub fn eval_condition(
                     }
 
                     mis.iter().fold(true, |res, mi| {
-                        let mut mi = mi.meta_item().unwrap().clone();
+                        let Some(mut mi) = mi.meta_item().cloned() else {
+                            dcx.emit_err(session_diagnostics::CfgPredicateIdentifier {
+                                span: mi.span(),
+                            });
+                            return false;
+                        };
+
                         if let [seg, ..] = &mut mi.path.segments[..] {
                             seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name));
                         }
diff --git a/tests/ui/cfg/cfg-target-compact-errors.rs b/tests/ui/cfg/cfg-target-compact-errors.rs
index daacbb2851d17..e00d42fe4d966 100644
--- a/tests/ui/cfg/cfg-target-compact-errors.rs
+++ b/tests/ui/cfg/cfg-target-compact-errors.rs
@@ -14,4 +14,8 @@ fn two() {}
 //~^ ERROR invalid predicate `target_pointer`
 fn three() {}
 
+#[cfg(target(true))]
+//~^ ERROR `cfg` predicate key must be an identifier
+fn four() {}
+
 fn main() {}
diff --git a/tests/ui/cfg/cfg-target-compact-errors.stderr b/tests/ui/cfg/cfg-target-compact-errors.stderr
index bb858301eb581..219d9732c32b6 100644
--- a/tests/ui/cfg/cfg-target-compact-errors.stderr
+++ b/tests/ui/cfg/cfg-target-compact-errors.stderr
@@ -16,7 +16,13 @@ error[E0537]: invalid predicate `target_pointer`
 LL | #[cfg(target(os = "linux", pointer(width = "64")))]
    |                            ^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: `cfg` predicate key must be an identifier
+  --> $DIR/cfg-target-compact-errors.rs:17:14
+   |
+LL | #[cfg(target(true))]
+   |              ^^^^
+
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0537, E0565.
 For more information about an error, try `rustc --explain E0537`.