1 files changed, 31 insertions, 12 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index 009e7e2487b..1703cab942b 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -24,6 +24,7 @@ use crate::attributes::{self, llfn_attrs_from_instance};
 use crate::builder::Builder;
 use crate::context::CodegenCx;
 use crate::llvm::{self, Attribute, AttributePlace};
+use crate::llvm_util;
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
@@ -41,12 +42,13 @@ trait ArgAttributesExt {
 const ABI_AFFECTING_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 1] =
     [(ArgAttribute::InReg, llvm::AttributeKind::InReg)];
 
-const OPTIMIZATION_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 5] = [
+const OPTIMIZATION_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 6] = [
     (ArgAttribute::NoAlias, llvm::AttributeKind::NoAlias),
-    (ArgAttribute::NoCapture, llvm::AttributeKind::NoCapture),
+    (ArgAttribute::CapturesAddress, llvm::AttributeKind::CapturesAddress),
     (ArgAttribute::NonNull, llvm::AttributeKind::NonNull),
     (ArgAttribute::ReadOnly, llvm::AttributeKind::ReadOnly),
     (ArgAttribute::NoUndef, llvm::AttributeKind::NoUndef),
+    (ArgAttribute::CapturesReadOnly, llvm::AttributeKind::CapturesReadOnly),
 ];
 
 fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'ll Attribute; 8]> {
@@ -82,6 +84,12 @@ fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'
         }
         for (attr, llattr) in OPTIMIZATION_ATTRIBUTES {
             if regular.contains(attr) {
+                // captures(...) is only available since LLVM 21.
+                if (attr == ArgAttribute::CapturesReadOnly || attr == ArgAttribute::CapturesAddress)
+                    && llvm_util::get_version() < (21, 0, 0)
+                {
+                    continue;
+                }
                 attrs.push(llattr.create_attr(cx.llcx));
             }
         }
@@ -207,9 +215,9 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
                 let align = attrs.pointee_align.unwrap_or(self.layout.align.abi);
                 OperandValue::Ref(PlaceValue::new_sized(val, align)).store(bx, dst);
             }
-            // Unsized indirect qrguments
+            // Unsized indirect arguments cannot be stored
             PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
-                bug!("unsized `ArgAbi` must be handled through `store_fn_arg`");
+                bug!("unsized `ArgAbi` cannot be stored");
             }
             PassMode::Cast { cast, pad_i32: _ } => {
                 // The ABI mandates that the value is passed as a different struct representation.
@@ -238,6 +246,7 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
                     scratch_align,
                     bx.const_usize(copy_bytes),
                     MemFlags::empty(),
+                    None,
                 );
                 bx.lifetime_end(llscratch, scratch_size);
             }
@@ -264,12 +273,7 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
                 OperandValue::Pair(next(), next()).store(bx, dst);
             }
             PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
-                let place_val = PlaceValue {
-                    llval: next(),
-                    llextra: Some(next()),
-                    align: self.layout.align.abi,
-                };
-                OperandValue::Ref(place_val).store(bx, dst);
+                bug!("unsized `ArgAbi` cannot be stored");
             }
             PassMode::Direct(_)
             | PassMode::Indirect { attrs: _, meta_attrs: None, on_stack: _ }
@@ -500,7 +504,16 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     }
                 }
                 PassMode::Indirect { attrs, meta_attrs: None, on_stack: false } => {
-                    apply(attrs);
+                    let i = apply(attrs);
+                    if cx.sess().opts.optimize != config::OptLevel::No
+                        && llvm_util::get_version() >= (21, 0, 0)
+                    {
+                        attributes::apply_to_llfn(
+                            llfn,
+                            llvm::AttributePlace::Argument(i),
+                            &[llvm::AttributeKind::DeadOnReturn.create_attr(cx.llcx)],
+                        );
+                    }
                 }
                 PassMode::Indirect { attrs, meta_attrs: Some(meta_attrs), on_stack } => {
                     assert!(!on_stack);
@@ -526,7 +539,13 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
 
         // If the declaration has an associated instance, compute extra attributes based on that.
         if let Some(instance) = instance {
-            llfn_attrs_from_instance(cx, llfn, instance);
+            llfn_attrs_from_instance(
+                cx,
+                cx.tcx,
+                llfn,
+                &cx.tcx.codegen_instance_attrs(instance.def),
+                Some(instance),
+            );
         }
     }