diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index 7857ccb613bf8..915dd3d9eda15 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -36,17 +36,17 @@ impl ArgAttributeExt for ArgAttribute {
     where
         F: FnMut(llvm::Attribute),
     {
-        for_each_kind!(self, f, NoAlias, NoCapture, NonNull, ReadOnly, SExt, StructRet, ZExt, InReg)
+        for_each_kind!(self, f, NoAlias, NoCapture, NonNull, ReadOnly, InReg)
     }
 }
 
 pub trait ArgAttributesExt {
-    fn apply_llfn(&self, idx: AttributePlace, llfn: &Value, ty: Option<&Type>);
-    fn apply_callsite(&self, idx: AttributePlace, callsite: &Value, ty: Option<&Type>);
+    fn apply_attrs_to_llfn(&self, idx: AttributePlace, llfn: &Value);
+    fn apply_attrs_to_callsite(&self, idx: AttributePlace, callsite: &Value);
 }
 
 impl ArgAttributesExt for ArgAttributes {
-    fn apply_llfn(&self, idx: AttributePlace, llfn: &Value, ty: Option<&Type>) {
+    fn apply_attrs_to_llfn(&self, idx: AttributePlace, llfn: &Value) {
         let mut regular = self.regular;
         unsafe {
             let deref = self.pointee_size.bytes();
@@ -61,14 +61,20 @@ impl ArgAttributesExt for ArgAttributes {
             if let Some(align) = self.pointee_align {
                 llvm::LLVMRustAddAlignmentAttr(llfn, idx.as_uint(), align.bytes() as u32);
             }
-            if regular.contains(ArgAttribute::ByVal) {
-                llvm::LLVMRustAddByValAttr(llfn, idx.as_uint(), ty.unwrap());
-            }
             regular.for_each_kind(|attr| attr.apply_llfn(idx, llfn));
+            match self.arg_ext {
+                ArgExtension::None => {}
+                ArgExtension::Zext => {
+                    llvm::Attribute::ZExt.apply_llfn(idx, llfn);
+                }
+                ArgExtension::Sext => {
+                    llvm::Attribute::SExt.apply_llfn(idx, llfn);
+                }
+            }
         }
     }
 
-    fn apply_callsite(&self, idx: AttributePlace, callsite: &Value, ty: Option<&Type>) {
+    fn apply_attrs_to_callsite(&self, idx: AttributePlace, callsite: &Value) {
         let mut regular = self.regular;
         unsafe {
             let deref = self.pointee_size.bytes();
@@ -91,10 +97,16 @@ impl ArgAttributesExt for ArgAttributes {
                     align.bytes() as u32,
                 );
             }
-            if regular.contains(ArgAttribute::ByVal) {
-                llvm::LLVMRustAddByValCallSiteAttr(callsite, idx.as_uint(), ty.unwrap());
-            }
             regular.for_each_kind(|attr| attr.apply_callsite(idx, callsite));
+            match self.arg_ext {
+                ArgExtension::None => {}
+                ArgExtension::Zext => {
+                    llvm::Attribute::ZExt.apply_callsite(idx, callsite);
+                }
+                ArgExtension::Sext => {
+                    llvm::Attribute::SExt.apply_callsite(idx, callsite);
+                }
+            }
         }
     }
 }
@@ -146,7 +158,7 @@ impl LlvmType for CastTarget {
             .prefix
             .iter()
             .flat_map(|option_kind| {
-                option_kind.map(|kind| Reg { kind, size: self.prefix_chunk }.llvm_type(cx))
+                option_kind.map(|kind| Reg { kind, size: self.prefix_chunk_size }.llvm_type(cx))
             })
             .chain((0..rest_count).map(|_| rest_ll_unit))
             .collect();
@@ -267,10 +279,12 @@ impl ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
             PassMode::Pair(..) => {
                 OperandValue::Pair(next(), next()).store(bx, dst);
             }
-            PassMode::Indirect(_, Some(_)) => {
+            PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => {
                 OperandValue::Ref(next(), Some(next()), self.layout.align.abi).store(bx, dst);
             }
-            PassMode::Direct(_) | PassMode::Indirect(_, None) | PassMode::Cast(_) => {
+            PassMode::Direct(_)
+            | PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ }
+            | PassMode::Cast(_) => {
                 let next_arg = next();
                 self.store(bx, next_arg, dst);
             }
@@ -315,14 +329,14 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             if let PassMode::Pair(_, _) = arg.mode { 2 } else { 1 }
         ).sum();
         let mut llargument_tys = Vec::with_capacity(
-            if let PassMode::Indirect(..) = self.ret.mode { 1 } else { 0 } + args_capacity,
+            if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 } + args_capacity,
         );
 
         let llreturn_ty = match self.ret.mode {
             PassMode::Ignore => cx.type_void(),
             PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
             PassMode::Cast(cast) => cast.llvm_type(cx),
-            PassMode::Indirect(..) => {
+            PassMode::Indirect { .. } => {
                 llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
                 cx.type_void()
             }
@@ -342,7 +356,7 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 1, true));
                     continue;
                 }
-                PassMode::Indirect(_, Some(_)) => {
+                PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => {
                     let ptr_ty = cx.tcx.mk_mut_ptr(arg.layout.ty);
                     let ptr_layout = cx.layout_of(ptr_ty);
                     llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 0, true));
@@ -350,7 +364,9 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     continue;
                 }
                 PassMode::Cast(cast) => cast.llvm_type(cx),
-                PassMode::Indirect(_, None) => cx.type_ptr_to(arg.memory_ty(cx)),
+                PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => {
+                    cx.type_ptr_to(arg.memory_ty(cx))
+                }
             };
             llargument_tys.push(llarg_ty);
         }
@@ -402,35 +418,54 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         }
 
         let mut i = 0;
-        let mut apply = |attrs: &ArgAttributes, ty: Option<&Type>| {
-            attrs.apply_llfn(llvm::AttributePlace::Argument(i), llfn, ty);
+        let mut apply = |attrs: &ArgAttributes| {
+            attrs.apply_attrs_to_llfn(llvm::AttributePlace::Argument(i), llfn);
             i += 1;
+            i - 1
         };
         match self.ret.mode {
             PassMode::Direct(ref attrs) => {
-                attrs.apply_llfn(llvm::AttributePlace::ReturnValue, llfn, None);
+                attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, llfn);
+            }
+            PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
+                assert!(!on_stack);
+                let i = apply(attrs);
+                llvm::Attribute::StructRet.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
             }
-            PassMode::Indirect(ref attrs, _) => apply(attrs, Some(self.ret.layout.llvm_type(cx))),
             _ => {}
         }
         for arg in &self.args {
             if arg.pad.is_some() {
-                apply(&ArgAttributes::new(), None);
+                apply(&ArgAttributes::new());
             }
             match arg.mode {
                 PassMode::Ignore => {}
-                PassMode::Direct(ref attrs) | PassMode::Indirect(ref attrs, None) => {
-                    apply(attrs, Some(arg.layout.llvm_type(cx)))
+                PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
+                    let i = apply(attrs);
+                    unsafe {
+                        llvm::LLVMRustAddByValAttr(
+                            llfn,
+                            llvm::AttributePlace::Argument(i).as_uint(),
+                            arg.layout.llvm_type(cx),
+                        );
+                    }
                 }
-                PassMode::Indirect(ref attrs, Some(ref extra_attrs)) => {
-                    apply(attrs, None);
-                    apply(extra_attrs, None);
+                PassMode::Direct(ref attrs)
+                | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
+                    apply(attrs);
+                }
+                PassMode::Indirect { ref attrs, extra_attrs: Some(ref extra_attrs), on_stack } => {
+                    assert!(!on_stack);
+                    apply(attrs);
+                    apply(extra_attrs);
                 }
                 PassMode::Pair(ref a, ref b) => {
-                    apply(a, None);
-                    apply(b, None);
+                    apply(a);
+                    apply(b);
+                }
+                PassMode::Cast(_) => {
+                    apply(&ArgAttributes::new());
                 }
-                PassMode::Cast(_) => apply(&ArgAttributes::new(), None),
             }
         }
     }
@@ -439,15 +474,21 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         // FIXME(wesleywiser, eddyb): We should apply `nounwind` and `noreturn` as appropriate to this callsite.
 
         let mut i = 0;
-        let mut apply = |attrs: &ArgAttributes, ty: Option<&Type>| {
-            attrs.apply_callsite(llvm::AttributePlace::Argument(i), callsite, ty);
+        let mut apply = |attrs: &ArgAttributes| {
+            attrs.apply_attrs_to_callsite(llvm::AttributePlace::Argument(i), callsite);
             i += 1;
+            i - 1
         };
         match self.ret.mode {
             PassMode::Direct(ref attrs) => {
-                attrs.apply_callsite(llvm::AttributePlace::ReturnValue, callsite, None);
+                attrs.apply_attrs_to_callsite(llvm::AttributePlace::ReturnValue, callsite);
+            }
+            PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
+                assert!(!on_stack);
+                let i = apply(attrs);
+                llvm::Attribute::StructRet
+                    .apply_callsite(llvm::AttributePlace::Argument(i), callsite);
             }
-            PassMode::Indirect(ref attrs, _) => apply(attrs, Some(self.ret.layout.llvm_type(bx))),
             _ => {}
         }
         if let abi::Abi::Scalar(ref scalar) = self.ret.layout.abi {
@@ -465,22 +506,39 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         }
         for arg in &self.args {
             if arg.pad.is_some() {
-                apply(&ArgAttributes::new(), None);
+                apply(&ArgAttributes::new());
             }
             match arg.mode {
                 PassMode::Ignore => {}
-                PassMode::Direct(ref attrs) | PassMode::Indirect(ref attrs, None) => {
-                    apply(attrs, Some(arg.layout.llvm_type(bx)))
+                PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
+                    let i = apply(attrs);
+                    unsafe {
+                        llvm::LLVMRustAddByValCallSiteAttr(
+                            callsite,
+                            llvm::AttributePlace::Argument(i).as_uint(),
+                            arg.layout.llvm_type(bx),
+                        );
+                    }
                 }
-                PassMode::Indirect(ref attrs, Some(ref extra_attrs)) => {
-                    apply(attrs, None);
-                    apply(extra_attrs, None);
+                PassMode::Direct(ref attrs)
+                | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
+                    apply(attrs);
+                }
+                PassMode::Indirect {
+                    ref attrs,
+                    extra_attrs: Some(ref extra_attrs),
+                    on_stack: _,
+                } => {
+                    apply(attrs);
+                    apply(extra_attrs);
                 }
                 PassMode::Pair(ref a, ref b) => {
-                    apply(a, None);
-                    apply(b, None);
+                    apply(a);
+                    apply(b);
+                }
+                PassMode::Cast(_) => {
+                    apply(&ArgAttributes::new());
                 }
-                PassMode::Cast(_) => apply(&ArgAttributes::new(), None),
             }
         }
 
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index ee40095883ded..fd20709f5d80f 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -255,7 +255,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             return;
         }
         let llval = match self.fn_abi.ret.mode {
-            PassMode::Ignore | PassMode::Indirect(..) => {
+            PassMode::Ignore | PassMode::Indirect { .. } => {
                 bx.ret_void();
                 return;
             }
@@ -1101,7 +1101,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // Force by-ref if we have to load through a cast pointer.
         let (mut llval, align, by_ref) = match op.val {
             Immediate(_) | Pair(..) => match arg.mode {
-                PassMode::Indirect(..) | PassMode::Cast(_) => {
+                PassMode::Indirect { .. } | PassMode::Cast(_) => {
                     let scratch = PlaceRef::alloca(bx, arg.layout);
                     op.val.store(bx, scratch);
                     (scratch.llval, scratch.align, true)
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 5626c864fe175..fa0711193df48 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -15,7 +15,7 @@ use rustc_session::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::DUMMY_SP;
 use rustc_target::abi::call::{
-    ArgAbi, ArgAttribute, ArgAttributes, Conv, FnAbi, PassMode, Reg, RegKind,
+    ArgAbi, ArgAttribute, ArgAttributes, ArgExtension, Conv, FnAbi, PassMode, Reg, RegKind,
 };
 use rustc_target::abi::*;
 use rustc_target::spec::{abi::Abi as SpecAbi, HasTargetSpec, PanicStrategy};
@@ -2619,7 +2619,7 @@ where
                                       is_return: bool| {
             // Booleans are always an i1 that needs to be zero-extended.
             if scalar.is_bool() {
-                attrs.set(ArgAttribute::ZExt);
+                attrs.ext(ArgExtension::Zext);
                 return;
             }
 
@@ -2801,9 +2801,6 @@ where
             for arg in &mut self.args {
                 fixup(arg, false);
             }
-            if let PassMode::Indirect(ref mut attrs, _) = self.ret.mode {
-                attrs.set(ArgAttribute::StructRet);
-            }
             return;
         }
 
diff --git a/compiler/rustc_target/src/abi/call/mips64.rs b/compiler/rustc_target/src/abi/call/mips64.rs
index 917dd104d1496..a630c84142b4d 100644
--- a/compiler/rustc_target/src/abi/call/mips64.rs
+++ b/compiler/rustc_target/src/abi/call/mips64.rs
@@ -1,4 +1,4 @@
-use crate::abi::call::{ArgAbi, ArgAttribute, CastTarget, FnAbi, PassMode, Reg, RegKind, Uniform};
+use crate::abi::call::{ArgAbi, ArgExtension, CastTarget, FnAbi, PassMode, Reg, RegKind, Uniform};
 use crate::abi::{self, HasDataLayout, LayoutOf, Size, TyAndLayout, TyAndLayoutMethods};
 
 fn extend_integer_width_mips<Ty>(arg: &mut ArgAbi<'_, Ty>, bits: u64) {
@@ -7,7 +7,7 @@ fn extend_integer_width_mips<Ty>(arg: &mut ArgAbi<'_, Ty>, bits: u64) {
         if let abi::Int(i, signed) = scalar.value {
             if !signed && i.size().bits() == 32 {
                 if let PassMode::Direct(ref mut attrs) = arg.mode {
-                    attrs.set(ArgAttribute::SExt);
+                    attrs.ext(ArgExtension::Sext);
                     return;
                 }
             }
@@ -137,7 +137,7 @@ where
     let rest_size = size - Size::from_bytes(8) * prefix_index as u64;
     arg.cast_to(CastTarget {
         prefix,
-        prefix_chunk: Size::from_bytes(8),
+        prefix_chunk_size: Size::from_bytes(8),
         rest: Uniform { unit: Reg::i64(), total: rest_size },
     });
 }
diff --git a/compiler/rustc_target/src/abi/call/mod.rs b/compiler/rustc_target/src/abi/call/mod.rs
index 429a3375cd893..5de9a8dfa7ac1 100644
--- a/compiler/rustc_target/src/abi/call/mod.rs
+++ b/compiler/rustc_target/src/abi/call/mod.rs
@@ -36,9 +36,12 @@ pub enum PassMode {
     /// a single uniform or a pair of registers.
     Cast(CastTarget),
     /// Pass the argument indirectly via a hidden pointer.
-    /// The second value, if any, is for the extra data (vtable or length)
+    /// The `extra_attrs` value, if any, is for the extra data (vtable or length)
     /// which indicates that it refers to an unsized rvalue.
-    Indirect(ArgAttributes, Option<ArgAttributes>),
+    /// `on_stack` defines that the the value should be passed at a fixed
+    /// stack offset in accordance to the ABI rather than passed using a
+    /// pointer. This corresponds to the `byval` LLVM argument attribute.
+    Indirect { attrs: ArgAttributes, extra_attrs: Option<ArgAttributes>, on_stack: bool },
 }
 
 // Hack to disable non_upper_case_globals only for the bitflags! and not for the rest
@@ -52,24 +55,31 @@ mod attr_impl {
     bitflags::bitflags! {
         #[derive(Default)]
         pub struct ArgAttribute: u16 {
-            const ByVal     = 1 << 0;
             const NoAlias   = 1 << 1;
             const NoCapture = 1 << 2;
             const NonNull   = 1 << 3;
             const ReadOnly  = 1 << 4;
-            const SExt      = 1 << 5;
-            const StructRet = 1 << 6;
-            const ZExt      = 1 << 7;
             const InReg     = 1 << 8;
         }
     }
 }
 
+/// Sometimes an ABI requires small integers to be extended to a full or partial register. This enum
+/// defines if this extension should be zero-extension or sign-extension when necssary. When it is
+/// not necesary to extend the argument, this enum is ignored.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum ArgExtension {
+    None,
+    Zext,
+    Sext,
+}
+
 /// A compact representation of LLVM attributes (at least those relevant for this module)
 /// that can be manipulated without interacting with LLVM's Attribute machinery.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct ArgAttributes {
     pub regular: ArgAttribute,
+    pub arg_ext: ArgExtension,
     /// The minimum size of the pointee, guaranteed to be valid for the duration of the whole call
     /// (corresponding to LLVM's dereferenceable and dereferenceable_or_null attributes).
     pub pointee_size: Size,
@@ -80,11 +90,18 @@ impl ArgAttributes {
     pub fn new() -> Self {
         ArgAttributes {
             regular: ArgAttribute::default(),
+            arg_ext: ArgExtension::None,
             pointee_size: Size::ZERO,
             pointee_align: None,
         }
     }
 
+    pub fn ext(&mut self, ext: ArgExtension) -> &mut Self {
+        assert!(self.arg_ext == ArgExtension::None || self.arg_ext == ext);
+        self.arg_ext = ext;
+        self
+    }
+
     pub fn set(&mut self, attr: ArgAttribute) -> &mut Self {
         self.regular |= attr;
         self
@@ -180,7 +197,7 @@ impl Uniform {
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub struct CastTarget {
     pub prefix: [Option<RegKind>; 8],
-    pub prefix_chunk: Size,
+    pub prefix_chunk_size: Size,
     pub rest: Uniform,
 }
 
@@ -192,7 +209,7 @@ impl From<Reg> for CastTarget {
 
 impl From<Uniform> for CastTarget {
     fn from(uniform: Uniform) -> CastTarget {
-        CastTarget { prefix: [None; 8], prefix_chunk: Size::ZERO, rest: uniform }
+        CastTarget { prefix: [None; 8], prefix_chunk_size: Size::ZERO, rest: uniform }
     }
 }
 
@@ -200,13 +217,13 @@ impl CastTarget {
     pub fn pair(a: Reg, b: Reg) -> CastTarget {
         CastTarget {
             prefix: [Some(a.kind), None, None, None, None, None, None, None],
-            prefix_chunk: a.size,
+            prefix_chunk_size: a.size,
             rest: Uniform::from(b),
         }
     }
 
     pub fn size<C: HasDataLayout>(&self, cx: &C) -> Size {
-        (self.prefix_chunk * self.prefix.iter().filter(|x| x.is_some()).count() as u64)
+        (self.prefix_chunk_size * self.prefix.iter().filter(|x| x.is_some()).count() as u64)
             .align_to(self.rest.align(cx))
             + self.rest.total
     }
@@ -214,7 +231,7 @@ impl CastTarget {
     pub fn align<C: HasDataLayout>(&self, cx: &C) -> Align {
         self.prefix
             .iter()
-            .filter_map(|x| x.map(|kind| Reg { kind, size: self.prefix_chunk }.align(cx)))
+            .filter_map(|x| x.map(|kind| Reg { kind, size: self.prefix_chunk_size }.align(cx)))
             .fold(cx.data_layout().aggregate_align.abi.max(self.rest.align(cx)), |acc, align| {
                 acc.max(align)
             })
@@ -438,14 +455,14 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
 
         let extra_attrs = self.layout.is_unsized().then_some(ArgAttributes::new());
 
-        self.mode = PassMode::Indirect(attrs, extra_attrs);
+        self.mode = PassMode::Indirect { attrs, extra_attrs, on_stack: false };
     }
 
     pub fn make_indirect_byval(&mut self) {
         self.make_indirect();
         match self.mode {
-            PassMode::Indirect(ref mut attrs, _) => {
-                attrs.set(ArgAttribute::ByVal);
+            PassMode::Indirect { attrs: _, extra_attrs: _, ref mut on_stack } => {
+                *on_stack = true;
             }
             _ => unreachable!(),
         }
@@ -457,7 +474,11 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
             if let abi::Int(i, signed) = scalar.value {
                 if i.size().bits() < bits {
                     if let PassMode::Direct(ref mut attrs) = self.mode {
-                        attrs.set(if signed { ArgAttribute::SExt } else { ArgAttribute::ZExt });
+                        if signed {
+                            attrs.ext(ArgExtension::Sext)
+                        } else {
+                            attrs.ext(ArgExtension::Zext)
+                        };
                     }
                 }
             }
@@ -474,15 +495,15 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
     }
 
     pub fn is_indirect(&self) -> bool {
-        matches!(self.mode, PassMode::Indirect(..))
+        matches!(self.mode, PassMode::Indirect {..})
     }
 
     pub fn is_sized_indirect(&self) -> bool {
-        matches!(self.mode, PassMode::Indirect(_, None))
+        matches!(self.mode, PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ })
     }
 
     pub fn is_unsized_indirect(&self) -> bool {
-        matches!(self.mode, PassMode::Indirect(_, Some(_)))
+        matches!(self.mode, PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ })
     }
 
     pub fn is_ignore(&self) -> bool {
@@ -591,10 +612,6 @@ impl<'a, Ty> FnAbi<'a, Ty> {
             a => return Err(format!("unrecognized arch \"{}\" in target specification", a)),
         }
 
-        if let PassMode::Indirect(ref mut attrs, _) = self.ret.mode {
-            attrs.set(ArgAttribute::StructRet);
-        }
-
         Ok(())
     }
 }
diff --git a/compiler/rustc_target/src/abi/call/riscv.rs b/compiler/rustc_target/src/abi/call/riscv.rs
index 782c661c31fdb..1ab881dd13d1c 100644
--- a/compiler/rustc_target/src/abi/call/riscv.rs
+++ b/compiler/rustc_target/src/abi/call/riscv.rs
@@ -4,7 +4,7 @@
 // Reference: Clang RISC-V ELF psABI lowering code
 // https://github.com/llvm/llvm-project/blob/8e780252a7284be45cf1ba224cabd884847e8e92/clang/lib/CodeGen/TargetInfo.cpp#L9311-L9773
 
-use crate::abi::call::{ArgAbi, ArgAttribute, CastTarget, FnAbi, PassMode, Reg, RegKind, Uniform};
+use crate::abi::call::{ArgAbi, ArgExtension, CastTarget, FnAbi, PassMode, Reg, RegKind, Uniform};
 use crate::abi::{
     self, Abi, FieldsShape, HasDataLayout, LayoutOf, Size, TyAndLayout, TyAndLayoutMethods,
 };
@@ -308,7 +308,7 @@ fn extend_integer_width<'a, Ty>(arg: &mut ArgAbi<'a, Ty>, xlen: u64) {
             // 32-bit integers are always sign-extended
             if i.size().bits() == 32 && xlen > 32 {
                 if let PassMode::Direct(ref mut attrs) = arg.mode {
-                    attrs.set(ArgAttribute::SExt);
+                    attrs.ext(ArgExtension::Sext);
                     return;
                 }
             }
diff --git a/compiler/rustc_target/src/abi/call/x86.rs b/compiler/rustc_target/src/abi/call/x86.rs
index 07bf1e94c617e..713b4100a3335 100644
--- a/compiler/rustc_target/src/abi/call/x86.rs
+++ b/compiler/rustc_target/src/abi/call/x86.rs
@@ -92,9 +92,14 @@ where
 
         for arg in &mut fn_abi.args {
             let attrs = match arg.mode {
-                PassMode::Ignore | PassMode::Indirect(_, None) => continue,
+                PassMode::Ignore
+                | PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => {
+                    continue;
+                }
                 PassMode::Direct(ref mut attrs) => attrs,
-                PassMode::Pair(..) | PassMode::Indirect(_, Some(_)) | PassMode::Cast(_) => {
+                PassMode::Pair(..)
+                | PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ }
+                | PassMode::Cast(_) => {
                     unreachable!("x86 shouldn't be passing arguments by {:?}", arg.mode)
                 }
             };