move rustc_codegen_ssa::target_features somewhere where it can be used by all codegen backends

Author: RalfJung

compiler/rustc_codegen_ssa/messages.ftl

@@ -1,7 +1,5 @@
 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
@@ -70,9 +68,6 @@ codegen_ssa_failed_to_write = failed to write {$path}: {$error}
 
 codegen_ssa_field_associated_value_expected = associated value expected for `{$name}`
 
-codegen_ssa_forbidden_target_feature_attr =
-    target feature `{$feature}` cannot be enabled with `#[target_feature]`: {$reason}
-
 codegen_ssa_ignoring_emit_path = ignoring emit path because multiple .{$extension} files were produced
 
 codegen_ssa_ignoring_output = ignoring -o because multiple .{$extension} files were produced
@@ -278,10 +273,6 @@ codegen_ssa_symbol_file_write_failure = failed to write symbols file: {$error}
 codegen_ssa_target_feature_disable_or_enable =
     the target features {$features} must all be either enabled or disabled together
 
-codegen_ssa_target_feature_safe_trait = `#[target_feature(..)]` cannot be applied to safe trait method
-    .label = cannot be applied to safe trait method
-    .label_def = not an `unsafe` function
-
 codegen_ssa_thorin_decompress_data = failed to decompress compressed section
 
 codegen_ssa_thorin_duplicate_unit = duplicate split compilation unit ({$unit})

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -16,6 +16,7 @@ use rustc_middle::middle::codegen_fn_attrs::{
 use rustc_middle::mir::mono::Linkage;
 use rustc_middle::query::Providers;
 use rustc_middle::span_bug;
+use rustc_middle::target_features::{check_target_feature_trait_unsafe, from_target_feature_attr};
 use rustc_middle::ty::{self as ty, TyCtxt};
 use rustc_session::parse::feature_err;
 use rustc_session::{Session, lint};
@@ -24,7 +25,6 @@ use rustc_target::spec::SanitizerSet;
 use tracing::debug;
 
 use crate::errors;
-use crate::target_features::{check_target_feature_trait_unsafe, from_target_feature_attr};
 
 fn linkage_by_name(tcx: TyCtxt<'_>, def_id: LocalDefId, name: &str) -> Linkage {
     use rustc_middle::mir::mono::Linkage::*;

compiler/rustc_codegen_ssa/src/errors.rs

@@ -1182,25 +1182,6 @@ pub(crate) struct InvalidLinkOrdinalFormat {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_target_feature_safe_trait)]
-pub(crate) struct TargetFeatureSafeTrait {
-    #[primary_span]
-    #[label]
-    pub span: Span,
-    #[label(codegen_ssa_label_def)]
-    pub def: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_forbidden_target_feature_attr)]
-pub struct ForbiddenTargetFeatureAttr<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub feature: &'a str,
-    pub reason: &'a str,
-}
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_failed_to_get_layout)]
 pub struct FailedToGetLayout<'tcx> {
@@ -1316,7 +1297,3 @@ pub(crate) struct XcrunSdkPathWarning {
     pub sdk_name: &'static str,
     pub stderr: String,
 }
-
-#[derive(LintDiagnostic)]
-#[diag(codegen_ssa_aarch64_softfloat_neon)]
-pub(crate) struct Aarch64SoftfloatNeon;

compiler/rustc_codegen_ssa/src/lib.rs

@@ -58,7 +58,6 @@ pub mod meth;
 pub mod mir;
 pub mod mono_item;
 pub mod size_of_val;
-pub mod target_features;
 pub mod traits;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
@@ -273,7 +272,6 @@ pub enum CodegenErrors {
 pub fn provide(providers: &mut Providers) {
     crate::back::symbol_export::provide(providers);
     crate::base::provide(providers);
-    crate::target_features::provide(providers);
     crate::codegen_attrs::provide(providers);
     providers.queries.global_backend_features = |_tcx: TyCtxt<'_>, ()| vec![];
 }

compiler/rustc_interface/src/passes.rs

@@ -786,7 +786,7 @@ pub static DEFAULT_QUERY_PROVIDERS: LazyLock<Providers> = LazyLock::new(|| {
     limits::provide(providers);
     proc_macro_decls::provide(providers);
     rustc_const_eval::provide(providers);
-    rustc_middle::hir::provide(providers);
+    rustc_middle::provide(providers);
     rustc_borrowck::provide(providers);
     rustc_incremental::provide(providers);
     rustc_mir_build::provide(providers);

compiler/rustc_middle/messages.ftl

@@ -1,3 +1,5 @@
+middle_aarch64_softfloat_neon = enabling the `neon` target feature on the current target is unsound due to ABI issues
+
 middle_assert_async_resume_after_drop = `async fn` resumed after async drop
 
 middle_assert_async_resume_after_panic = `async fn` resumed after panicking
@@ -78,6 +80,9 @@ middle_erroneous_constant = erroneous constant encountered
 middle_failed_writing_file =
     failed to write file {$path}: {$error}"
 
+middle_forbidden_target_feature_attr =
+    target feature `{$feature}` cannot be enabled with `#[target_feature]`: {$reason}
+
 middle_layout_cycle =
     a cycle occurred during layout computation
 
@@ -112,6 +117,10 @@ middle_strict_coherence_needs_negative_coherence =
     to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled
     .label = due to this attribute
 
+middle_target_feature_safe_trait = `#[target_feature(..)]` cannot be applied to safe trait method
+    .label = cannot be applied to safe trait method
+    .label_def = not an `unsafe` function
+
 middle_type_length_limit = reached the type-length limit while instantiating `{$shrunk}`
 
 middle_unsupported_union = we don't support unions yet: '{$ty_name}'

compiler/rustc_middle/src/error.rs

@@ -3,7 +3,7 @@ use std::{fmt, io};
 
 use rustc_errors::codes::*;
 use rustc_errors::{DiagArgName, DiagArgValue, DiagMessage};
-use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
 use crate::ty::Ty;
@@ -170,3 +170,26 @@ pub(crate) struct TypeLengthLimit {
     pub path: PathBuf,
     pub type_length: usize,
 }
+
+#[derive(Diagnostic)]
+#[diag(middle_forbidden_target_feature_attr)]
+pub struct ForbiddenTargetFeatureAttr<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub feature: &'a str,
+    pub reason: &'a str,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(middle_aarch64_softfloat_neon)]
+pub(crate) struct Aarch64SoftfloatNeon;
+
+#[derive(Diagnostic)]
+#[diag(middle_target_feature_safe_trait)]
+pub(crate) struct TargetFeatureSafeTrait {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[label(middle_label_def)]
+    pub def: Span,
+}

compiler/rustc_middle/src/hir/mod.rs

@@ -177,7 +177,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 }
 
-pub fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers) {
     providers.hir_crate_items = map::hir_crate_items;
     providers.crate_hash = map::crate_hash;
     providers.hir_module_items = map::hir_module_items;

compiler/rustc_middle/src/lib.rs

@@ -78,6 +78,7 @@ pub mod lint;
 pub mod metadata;
 pub mod middle;
 pub mod mir;
+pub mod target_features;
 pub mod thir;
 pub mod traits;
 pub mod ty;
@@ -93,3 +94,8 @@ pub mod dep_graph;
 extern crate self as rustc_middle;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
+
+pub fn provide(providers: &mut util::Providers) {
+    hir::provide(providers);
+    target_features::provide(providers);
+}

compiler/rustc_codegen_ssa/src/target_features.rs renamed to compiler/rustc_middle/src/target_features.rs

@@ -1,23 +1,24 @@
+//! Shared utilities for dealing with target features that haven't (yet) found a better home.
 use rustc_attr_data_structures::InstructionSetAttr;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 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_lint_defs::builtin::AARCH64_SOFTFLOAT_NEON;
 use rustc_session::parse::feature_err;
 use rustc_span::{Span, Symbol, sym};
 use rustc_target::target_features::{self, Stability};
 
-use crate::errors;
+use crate::error;
+use crate::middle::codegen_fn_attrs::TargetFeature;
+use crate::query::Providers;
+use crate::ty::TyCtxt;
 
 /// Compute the enabled target features from the `#[target_feature]` function attribute.
 /// Enabled target features are added to `target_features`.
-pub(crate) fn from_target_feature_attr(
+pub fn from_target_feature_attr(
     tcx: TyCtxt<'_>,
     did: LocalDefId,
     attr: &hir::Attribute,
@@ -67,7 +68,7 @@ pub(crate) fn from_target_feature_attr(
             // Only allow target features whose feature gates have been enabled
             // and which are permitted to be toggled.
             if let Err(reason) = stability.toggle_allowed() {
-                tcx.dcx().emit_err(errors::ForbiddenTargetFeatureAttr {
+                tcx.dcx().emit_err(error::ForbiddenTargetFeatureAttr {
                     span: item.span(),
                     feature,
                     reason,
@@ -101,10 +102,10 @@ pub(crate) fn from_target_feature_attr(
                                     AARCH64_SOFTFLOAT_NEON,
                                     tcx.local_def_id_to_hir_id(did),
                                     item.span(),
-                                    errors::Aarch64SoftfloatNeon,
+                                    error::Aarch64SoftfloatNeon,
                                 );
                             } else {
-                                tcx.dcx().emit_err(errors::ForbiddenTargetFeatureAttr {
+                                tcx.dcx().emit_err(error::ForbiddenTargetFeatureAttr {
                                     span: item.span(),
                                     feature: name.as_str(),
                                     reason: "this feature is incompatible with the target ABI",
@@ -143,14 +144,12 @@ fn asm_target_features(tcx: TyCtxt<'_>, did: DefId) -> &FxIndexSet<Symbol> {
 
 /// Checks the function annotated with `#[target_feature]` is not a safe
 /// trait method implementation, reporting an error if it is.
-pub(crate) fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
+pub fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
     if let DefKind::AssocFn = tcx.def_kind(id) {
         let parent_id = tcx.local_parent(id);
         if let DefKind::Trait | DefKind::Impl { of_trait: true } = tcx.def_kind(parent_id) {
-            tcx.dcx().emit_err(errors::TargetFeatureSafeTrait {
-                span: attr_span,
-                def: tcx.def_span(id),
-            });
+            tcx.dcx()
+                .emit_err(error::TargetFeatureSafeTrait { span: attr_span, def: tcx.def_span(id) });
         }
     }
 }