1 files changed, 34 insertions, 10 deletions

diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 3877460fcdb..fde95104093 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -1,23 +1,21 @@
 //! Set and unset common attributes on LLVM values.
 
+pub use rustc_attr::{InlineAttr, InstructionSetAttr, OptimizeAttr};
 use rustc_codegen_ssa::traits::*;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, PatchableFunctionEntry};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_session::config::{FunctionReturn, OptLevel};
+use rustc_session::config::{BranchProtection, FunctionReturn, OptLevel, PAuthKey, PacRet};
 use rustc_span::symbol::sym;
 use rustc_target::spec::{FramePointer, SanitizerSet, StackProbeType, StackProtector};
 use smallvec::SmallVec;
 
-use crate::attributes;
+use crate::context::CodegenCx;
 use crate::errors::{MissingFeatures, SanitizerMemtagRequiresMte, TargetFeatureDisableOrEnable};
 use crate::llvm::AttributePlace::Function;
 use crate::llvm::{self, AllocKindFlags, Attribute, AttributeKind, AttributePlace, MemoryEffects};
-use crate::llvm_util;
-pub use rustc_attr::{InlineAttr, InstructionSetAttr, OptimizeAttr};
-
-use crate::context::CodegenCx;
 use crate::value::Value;
+use crate::{attributes, llvm_util};
 
 pub fn apply_to_llfn(llfn: &Value, idx: AttributePlace, attrs: &[&Attribute]) {
     if !attrs.is_empty() {
@@ -326,9 +324,10 @@ fn create_alloc_family_attr(llcx: &llvm::Context) -> &llvm::Attribute {
     llvm::CreateAttrStringValue(llcx, "alloc-family", "__rust_alloc")
 }
 
+/// Helper for `FnAbi::apply_attrs_llfn`:
 /// Composite function which sets LLVM attributes for function depending on its AST (`#[attribute]`)
 /// attributes.
-pub fn from_fn_attrs<'ll, 'tcx>(
+pub fn llfn_attrs_from_instance<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     llfn: &'ll Value,
     instance: ty::Instance<'tcx>,
@@ -407,8 +406,33 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         // And it is a module-level attribute, so the alternative is pulling naked functions into new LLVM modules.
         // Otherwise LLVM's "naked" functions come with endbr prefixes per https://github.com/rust-lang/rust/issues/98768
         to_add.push(AttributeKind::NoCfCheck.create_attr(cx.llcx));
-        // Need this for AArch64.
-        to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
+        if llvm_util::get_version() < (19, 0, 0) {
+            // Prior to LLVM 19, branch-target-enforcement was disabled by setting the attribute to
+            // the string "false". Now it is disabled by absence of the attribute.
+            to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
+        }
+    } else if llvm_util::get_version() >= (19, 0, 0) {
+        // For non-naked functions, set branch protection attributes on aarch64.
+        if let Some(BranchProtection { bti, pac_ret }) =
+            cx.sess().opts.unstable_opts.branch_protection
+        {
+            assert!(cx.sess().target.arch == "aarch64");
+            if bti {
+                to_add.push(llvm::CreateAttrString(cx.llcx, "branch-target-enforcement"));
+            }
+            if let Some(PacRet { leaf, key }) = pac_ret {
+                to_add.push(llvm::CreateAttrStringValue(
+                    cx.llcx,
+                    "sign-return-address",
+                    if leaf { "all" } else { "non-leaf" },
+                ));
+                to_add.push(llvm::CreateAttrStringValue(
+                    cx.llcx,
+                    "sign-return-address-key",
+                    if key == PAuthKey::A { "a_key" } else { "b_key" },
+                ));
+            }
+        }
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR)
         || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR_ZEROED)
@@ -473,7 +497,7 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     to_add.extend(tune_cpu_attr(cx));
 
     let function_features =
-        codegen_fn_attrs.target_features.iter().map(|f| f.as_str()).collect::<Vec<&str>>();
+        codegen_fn_attrs.target_features.iter().map(|f| f.name.as_str()).collect::<Vec<&str>>();
 
     if let Some(f) = llvm_util::check_tied_features(
         cx.tcx.sess,