Merge from rustc

7 files changed, 32 insertions, 11 deletions

diff --git a/compiler/rustc_codegen_ssa/messages.ftl b/compiler/rustc_codegen_ssa/messages.ftl
index 2621935eecf..acb4cbaa13f 100644
--- a/compiler/rustc_codegen_ssa/messages.ftl
+++ b/compiler/rustc_codegen_ssa/messages.ftl
@@ -1,5 +1,7 @@
 codegen_ssa_L4Bender_exporting_symbols_unimplemented = exporting symbols not implemented yet for L4Bender
 
+codegen_ssa_aarch64_softfloat_neon = enabling the `neon` target feature on the current target is unsound due to ABI issues
+
 codegen_ssa_add_native_library = failed to add native library {$library_path}: {$error}
 
 codegen_ssa_aix_strip_not_used = using host's `strip` binary to cross-compile to AIX which is not guaranteed to work
diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index 96aec9769d2..e26f999773d 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -128,7 +128,7 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, _: LocalCrate) -> DefIdMap<S
                 } else {
                     SymbolExportKind::Text
                 },
-                used: codegen_attrs.flags.contains(CodegenFnAttrFlags::USED)
+                used: codegen_attrs.flags.contains(CodegenFnAttrFlags::USED_COMPILER)
                     || codegen_attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER)
                     || used,
             };
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index aa55a0e0f14..4bcafa3be36 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -189,7 +189,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                             )
                             .emit();
                         }
-                        codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
+                        codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED_COMPILER;
                     }
                     Some(_) => {
                         tcx.dcx().emit_err(errors::ExpectedUsedSymbol { span: attr.span() });
@@ -220,7 +220,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                             || tcx.sess.target.is_like_windows
                             || tcx.sess.target.is_like_wasm);
                         codegen_fn_attrs.flags |= if is_like_elf {
-                            CodegenFnAttrFlags::USED
+                            CodegenFnAttrFlags::USED_COMPILER
                         } else {
                             CodegenFnAttrFlags::USED_LINKER
                         };
@@ -299,6 +299,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                 }
                 from_target_feature_attr(
                     tcx,
+                    did,
                     attr,
                     rust_target_features,
                     &mut codegen_fn_attrs.target_features,
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index d49aac75d05..572d7b1e06a 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -1316,3 +1316,7 @@ pub(crate) struct XcrunSdkPathWarning {
     pub sdk_name: &'static str,
     pub stderr: String,
 }
+
+#[derive(LintDiagnostic)]
+#[diag(codegen_ssa_aarch64_softfloat_neon)]
+pub(crate) struct Aarch64SoftfloatNeon;
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 950f19a6f0f..600d6ff6801 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -1181,6 +1181,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             (_, Some(llfn)) => llfn,
             _ => span_bug!(span, "no instance or llfn for call"),
         };
+        self.set_debug_loc(bx, mir::SourceInfo { span: fn_span, ..source_info });
         helper.do_call(
             self,
             bx,
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index 5924c8991ad..f731613d67e 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -10,7 +10,7 @@ use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
 use rustc_middle::ty::{Instance, Ty};
 use rustc_middle::{bug, mir, ty};
 use rustc_session::config::DebugInfo;
-use rustc_span::{BytePos, Span, Symbol, hygiene, kw};
+use rustc_span::{BytePos, Span, Symbol, hygiene, sym};
 
 use super::operand::{OperandRef, OperandValue};
 use super::place::{PlaceRef, PlaceValue};
@@ -283,7 +283,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 // (after #67586 gets fixed).
                 None
             } else {
-                let name = kw::Empty;
+                let name = sym::empty;
                 let decl = &self.mir.local_decls[local];
                 let dbg_var = if full_debug_info {
                     self.adjusted_span_and_dbg_scope(decl.source_info).map(
@@ -318,7 +318,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             None
         } else {
             Some(match whole_local_var.or(fallback_var.clone()) {
-                Some(var) if var.name != kw::Empty => var.name.to_string(),
+                Some(var) if var.name != sym::empty => var.name.to_string(),
                 _ => format!("{local:?}"),
             })
         };
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index 3ecea522837..6bb3150c1c5 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -8,6 +8,7 @@ use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
 use rustc_middle::middle::codegen_fn_attrs::TargetFeature;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
+use rustc_session::lint::builtin::AARCH64_SOFTFLOAT_NEON;
 use rustc_session::parse::feature_err;
 use rustc_span::{Span, Symbol, sym};
 use rustc_target::target_features::{self, Stability};
@@ -18,6 +19,7 @@ use crate::errors;
 /// Enabled target features are added to `target_features`.
 pub(crate) fn from_target_feature_attr(
     tcx: TyCtxt<'_>,
+    did: LocalDefId,
     attr: &hir::Attribute,
     rust_target_features: &UnordMap<String, target_features::Stability>,
     target_features: &mut Vec<TargetFeature>,
@@ -92,11 +94,22 @@ pub(crate) fn from_target_feature_attr(
                     // generating code so "it's fine".
                     if !tcx.sess.opts.actually_rustdoc {
                         if abi_feature_constraints.incompatible.contains(&name.as_str()) {
-                            tcx.dcx().emit_err(errors::ForbiddenTargetFeatureAttr {
-                                span: item.span(),
-                                feature: name.as_str(),
-                                reason: "this feature is incompatible with the target ABI",
-                            });
+                            // For "neon" specifically, we emit an FCW instead of a hard error.
+                            // See <https://github.com/rust-lang/rust/issues/134375>.
+                            if tcx.sess.target.arch == "aarch64" && name.as_str() == "neon" {
+                                tcx.emit_node_span_lint(
+                                    AARCH64_SOFTFLOAT_NEON,
+                                    tcx.local_def_id_to_hir_id(did),
+                                    item.span(),
+                                    errors::Aarch64SoftfloatNeon,
+                                );
+                            } else {
+                                tcx.dcx().emit_err(errors::ForbiddenTargetFeatureAttr {
+                                    span: item.span(),
+                                    feature: name.as_str(),
+                                    reason: "this feature is incompatible with the target ABI",
+                                });
+                            }
                         }
                     }
                     target_features.push(TargetFeature { name, implied: name != feature_sym })