Auto merge of #128063 - tgross35:rollup-hsxmptf, r=tgross35

Rollup of 9 pull requests

Successful merges:

 - #117932 (Correct rustdoc section where we talk about rustdoc emitting errors on invalid code)
 - #125990 (Rename `deprecated_safe` lint to `deprecated_safe_2024`)
 - #127506 (rustc_target: add known safe s390x target features)
 - #127820 (Rewrite and rename `issue-14698`. `issue-33329` and `issue-107094` `run-make` tests to rmake or ui)
 - #127923 (Use reuse tool 4.0)
 - #128008 (Start using `#[diagnostic::do_not_recommend]` in the standard library)
 - #128036 (add more tests)
 - #128051 (rustdoc: revert spacing change in item-table)
 - #128059 (Add regression test for items list size (#128023))

r? `@ghost`
`@rustbot` modify labels: rollup

9 files changed, 52 insertions, 9 deletions

diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index e7669470026..3877460fcdb 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -271,6 +271,17 @@ fn stackprotector_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
     Some(sspattr.create_attr(cx.llcx))
 }
 
+fn backchain_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
+    if cx.sess().target.arch != "s390x" {
+        return None;
+    }
+
+    let requested_features = cx.sess().opts.cg.target_feature.split(',');
+    let found_positive = requested_features.clone().any(|r| r == "+backchain");
+
+    if found_positive { Some(llvm::CreateAttrString(cx.llcx, "backchain")) } else { None }
+}
+
 pub fn target_cpu_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> &'ll Attribute {
     let target_cpu = llvm_util::target_cpu(cx.tcx.sess);
     llvm::CreateAttrStringValue(cx.llcx, "target-cpu", target_cpu)
@@ -447,6 +458,9 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     if let Some(align) = codegen_fn_attrs.alignment {
         llvm::set_alignment(llfn, align);
     }
+    if let Some(backchain) = backchain_attr(cx) {
+        to_add.push(backchain);
+    }
     to_add.extend(sanitize_attrs(cx, codegen_fn_attrs.no_sanitize));
     to_add.extend(patchable_function_entry_attrs(cx, codegen_fn_attrs.patchable_function_entry));
 
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 98dc8ac86d2..4d56d1d3b1a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -14,7 +14,7 @@ use rustc_session::config::{PrintKind, PrintRequest};
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{MergeFunctions, PanicStrategy};
-use rustc_target::target_features::RUSTC_SPECIFIC_FEATURES;
+use rustc_target::target_features::{RUSTC_SPECIAL_FEATURES, RUSTC_SPECIFIC_FEATURES};
 
 use std::ffi::{c_char, c_void, CStr, CString};
 use std::fmt::Write;
@@ -321,6 +321,10 @@ pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
             }
         })
         .filter(|feature| {
+            // skip checking special features, as LLVM may not understands them
+            if RUSTC_SPECIAL_FEATURES.contains(feature) {
+                return true;
+            }
             // check that all features in a given smallvec are enabled
             for llvm_feature in to_llvm_features(sess, feature) {
                 let cstr = SmallCStr::new(llvm_feature);
@@ -546,6 +550,7 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
 
     // -Ctarget-features
     let supported_features = sess.target.supported_target_features();
+    let (llvm_major, _, _) = get_version();
     let mut featsmap = FxHashMap::default();
     let feats = sess
         .opts
@@ -604,6 +609,13 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
             if RUSTC_SPECIFIC_FEATURES.contains(&feature) {
                 return None;
             }
+
+            // if the target-feature is "backchain" and LLVM version is greater than 18
+            // then we also need to add "+backchain" to the target-features attribute.
+            // otherwise, we will only add the naked `backchain` attribute to the attribute-group.
+            if feature == "backchain" && llvm_major < 18 {
+                return None;
+            }
             // ... otherwise though we run through `to_llvm_features` when
             // passing requests down to LLVM. This means that all in-language
             // features also work on the command line instead of having two
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index cea164df617..e7cee5220d6 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -82,6 +82,7 @@ pub fn from_target_feature(
                 Some(sym::prfchw_target_feature) => rust_features.prfchw_target_feature,
                 Some(sym::x86_amx_intrinsics) => rust_features.x86_amx_intrinsics,
                 Some(sym::xop_target_feature) => rust_features.xop_target_feature,
+                Some(sym::s390x_target_feature) => rust_features.s390x_target_feature,
                 Some(name) => bug!("unknown target feature gate {}", name),
                 None => true,
             };
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 741c621db08..9b5ed3b0876 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -312,6 +312,7 @@ declare_features! (
     (unstable, prfchw_target_feature, "1.78.0", Some(44839)),
     (unstable, riscv_target_feature, "1.45.0", Some(44839)),
     (unstable, rtm_target_feature, "1.35.0", Some(44839)),
+    (unstable, s390x_target_feature, "CURRENT_RUSTC_VERSION", Some(44839)),
     (unstable, sse4a_target_feature, "1.27.0", Some(44839)),
     (unstable, tbm_target_feature, "1.27.0", Some(44839)),
     (unstable, wasm_target_feature, "1.30.0", Some(44839)),
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 290f91045c4..fc073233d97 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -322,6 +322,8 @@ fn register_builtins(store: &mut LintStore) {
         REFINING_IMPL_TRAIT_INTERNAL
     );
 
+    add_lint_group!("deprecated_safe", DEPRECATED_SAFE_2024);
+
     // Register renamed and removed lints.
     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 04764b71b10..2f4e6a32308 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -37,7 +37,7 @@ declare_lint_pass! {
         DEPRECATED,
         DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
         DEPRECATED_IN_FUTURE,
-        DEPRECATED_SAFE,
+        DEPRECATED_SAFE_2024,
         DEPRECATED_WHERE_CLAUSE_LOCATION,
         DUPLICATE_MACRO_ATTRIBUTES,
         ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT,
@@ -4812,8 +4812,8 @@ declare_lint! {
 }
 
 declare_lint! {
-    /// The `deprecated_safe` lint detects unsafe functions being used as safe
-    /// functions.
+    /// The `deprecated_safe_2024` lint detects unsafe functions being used as
+    /// safe functions.
     ///
     /// ### Example
     ///
@@ -4832,8 +4832,8 @@ declare_lint! {
     ///
     /// Rust [editions] allow the language to evolve without breaking backward
     /// compatibility. This lint catches code that uses `unsafe` functions that
-    /// were declared as safe (non-`unsafe`) in earlier editions. If you switch
-    /// the compiler to a new edition without updating the code, then it
+    /// were declared as safe (non-`unsafe`) in editions prior to Rust 2024. If
+    /// you switch the compiler to Rust 2024 without updating the code, then it
     /// will fail to compile if you are using a function previously marked as
     /// safe.
     ///
@@ -4850,7 +4850,7 @@ declare_lint! {
     /// future.
     ///
     /// [editions]: https://doc.rust-lang.org/edition-guide/
-    pub DEPRECATED_SAFE,
+    pub DEPRECATED_SAFE_2024,
     Allow,
     "detects unsafe functions being used as safe functions",
     @future_incompatible = FutureIncompatibleInfo {
diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index a65586ccdb7..bff4d6af4aa 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -10,7 +10,7 @@ use rustc_middle::thir::visit::Visitor;
 use rustc_middle::thir::*;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt};
-use rustc_session::lint::builtin::{DEPRECATED_SAFE, UNSAFE_OP_IN_UNSAFE_FN, UNUSED_UNSAFE};
+use rustc_session::lint::builtin::{DEPRECATED_SAFE_2024, UNSAFE_OP_IN_UNSAFE_FN, UNUSED_UNSAFE};
 use rustc_session::lint::Level;
 use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::symbol::Symbol;
@@ -99,7 +99,7 @@ impl<'tcx> UnsafetyVisitor<'_, 'tcx> {
             {
                 let sm = self.tcx.sess.source_map();
                 self.tcx.emit_node_span_lint(
-                    DEPRECATED_SAFE,
+                    DEPRECATED_SAFE_2024,
                     self.hir_context,
                     span,
                     CallToDeprecatedSafeFnRequiresUnsafe {
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 5ae01389116..2b30ca8a894 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1691,6 +1691,7 @@ symbols! {
         rvalue_static_promotion,
         rwpi,
         s,
+        s390x_target_feature,
         safety,
         sanitize,
         sanitizer_cfi_generalize_pointers,
diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs
index 6667efb14e2..4fb0323b6cf 100644
--- a/compiler/rustc_target/src/target_features.rs
+++ b/compiler/rustc_target/src/target_features.rs
@@ -4,6 +4,9 @@ use rustc_span::symbol::Symbol;
 /// Features that control behaviour of rustc, rather than the codegen.
 pub const RUSTC_SPECIFIC_FEATURES: &[&str] = &["crt-static"];
 
+/// Features that require special handling when passing to LLVM.
+pub const RUSTC_SPECIAL_FEATURES: &[&str] = &["backchain"];
+
 /// Stability information for target features.
 #[derive(Debug, Clone, Copy)]
 pub enum Stability {
@@ -397,6 +400,13 @@ const LOONGARCH_ALLOWED_FEATURES: &[(&str, Stability)] = &[
     // tidy-alphabetical-end
 ];
 
+const IBMZ_ALLOWED_FEATURES: &[(&str, Stability)] = &[
+    // tidy-alphabetical-start
+    ("backchain", Unstable(sym::s390x_target_feature)),
+    ("vector", Unstable(sym::s390x_target_feature)),
+    // tidy-alphabetical-end
+];
+
 /// When rustdoc is running, provide a list of all known features so that all their respective
 /// primitives may be documented.
 ///
@@ -414,6 +424,7 @@ pub fn all_known_features() -> impl Iterator<Item = (&'static str, Stability)> {
         .chain(BPF_ALLOWED_FEATURES.iter())
         .chain(CSKY_ALLOWED_FEATURES)
         .chain(LOONGARCH_ALLOWED_FEATURES)
+        .chain(IBMZ_ALLOWED_FEATURES)
         .cloned()
 }
 
@@ -431,6 +442,7 @@ impl super::spec::Target {
             "bpf" => BPF_ALLOWED_FEATURES,
             "csky" => CSKY_ALLOWED_FEATURES,
             "loongarch64" => LOONGARCH_ALLOWED_FEATURES,
+            "s390x" => IBMZ_ALLOWED_FEATURES,
             _ => &[],
         }
     }