ty::layout: replicate `layout_of` setup for `fn_abi_of_{fn_ptr,instance}`.

17 files changed, 277 insertions, 157 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 13790409e59..6317e1d5d1a 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -5,7 +5,7 @@ mod pass_mode;
 mod returning;
 
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc_middle::ty::layout::FnAbiExt;
+use rustc_middle::ty::layout::FnAbiOf;
 use rustc_target::abi::call::{Conv, FnAbi};
 use rustc_target::spec::abi::Abi;
 
@@ -53,7 +53,7 @@ pub(crate) fn get_function_sig<'tcx>(
     inst: Instance<'tcx>,
 ) -> Signature {
     assert!(!inst.substs.needs_infer());
-    clif_sig_from_fn_abi(tcx, triple, &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]))
+    clif_sig_from_fn_abi(tcx, triple, &RevealAllLayoutCx(tcx).fn_abi_of_instance(inst, &[]))
 }
 
 /// Instance must be monomorphized
@@ -355,9 +355,9 @@ pub(crate) fn codegen_terminator_call<'tcx>(
         .map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))
         .collect::<Vec<_>>();
     let fn_abi = if let Some(instance) = instance {
-        FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), instance, &extra_args)
+        RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(instance, &extra_args)
     } else {
-        FnAbi::of_fn_ptr(&RevealAllLayoutCx(fx.tcx), fn_ty.fn_sig(fx.tcx), &extra_args)
+        RevealAllLayoutCx(fx.tcx).fn_abi_of_fn_ptr(fn_ty.fn_sig(fx.tcx), &extra_args)
     };
 
     let is_cold = instance
@@ -525,7 +525,7 @@ pub(crate) fn codegen_drop<'tcx>(
                     def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
                     substs: drop_instance.substs,
                 };
-                let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), virtual_drop, &[]);
+                let fn_abi = RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(virtual_drop, &[]);
 
                 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
                 let sig = fx.bcx.import_signature(sig);
@@ -534,7 +534,7 @@ pub(crate) fn codegen_drop<'tcx>(
             _ => {
                 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
 
-                let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
+                let fn_abi = RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(drop_instance, &[]);
 
                 let arg_value = drop_place.place_ref(
                     fx,
diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
index d29558a4e1f..872c7edc791 100644
--- a/compiler/rustc_codegen_cranelift/src/base.rs
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -3,8 +3,7 @@
 use cranelift_codegen::binemit::{NullStackMapSink, NullTrapSink};
 use rustc_index::vec::IndexVec;
 use rustc_middle::ty::adjustment::PointerCast;
-use rustc_middle::ty::layout::FnAbiExt;
-use rustc_target::abi::call::FnAbi;
+use rustc_middle::ty::layout::FnAbiOf;
 
 use crate::constant::ConstantCx;
 use crate::prelude::*;
@@ -62,7 +61,7 @@ pub(crate) fn codegen_fn<'tcx>(
         instance,
         symbol_name,
         mir,
-        fn_abi: Some(FnAbi::of_instance(&RevealAllLayoutCx(tcx), instance, &[])),
+        fn_abi: Some(RevealAllLayoutCx(tcx).fn_abi_of_instance(instance, &[])),
 
         bcx,
         block_map,
diff --git a/compiler/rustc_codegen_cranelift/src/common.rs b/compiler/rustc_codegen_cranelift/src/common.rs
index 06d1fc717cc..4a8be89460f 100644
--- a/compiler/rustc_codegen_cranelift/src/common.rs
+++ b/compiler/rustc_codegen_cranelift/src/common.rs
@@ -1,5 +1,7 @@
 use rustc_index::vec::IndexVec;
-use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers};
+use rustc_middle::ty::layout::{
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOfHelpers,
+};
 use rustc_middle::ty::SymbolName;
 use rustc_target::abi::call::FnAbi;
 use rustc_target::abi::{Integer, Primitive};
@@ -266,6 +268,20 @@ impl<'tcx> LayoutOfHelpers<'tcx> for FunctionCx<'_, '_, 'tcx> {
     }
 }
 
+impl<'tcx> FnAbiOfHelpers<'tcx> for FunctionCx<'_, '_, 'tcx> {
+    type FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'_, 'tcx>,
+    ) -> ! {
+        RevealAllLayoutCx(self.tcx).handle_fn_abi_err(err, span, fn_abi_request)
+    }
+}
+
 impl<'tcx> layout::HasTyCtxt<'tcx> for FunctionCx<'_, '_, 'tcx> {
     fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.tcx
@@ -378,6 +394,43 @@ impl<'tcx> LayoutOfHelpers<'tcx> for RevealAllLayoutCx<'tcx> {
     }
 }
 
+impl<'tcx> FnAbiOfHelpers<'tcx> for RevealAllLayoutCx<'tcx> {
+    type FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'_, 'tcx>,
+    ) -> ! {
+        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
+            self.0.sess.span_fatal(span, &err.to_string())
+        } else {
+            match fn_abi_request {
+                FnAbiRequest::OfFnPtr { sig, extra_args } => {
+                    span_bug!(
+                        span,
+                        "`fn_abi_of_fn_ptr({}, {:?})` failed: {}",
+                        sig,
+                        extra_args,
+                        err
+                    );
+                }
+                FnAbiRequest::OfInstance { instance, extra_args } => {
+                    span_bug!(
+                        span,
+                        "`fn_abi_of_instance({}, {:?})` failed: {}",
+                        instance,
+                        extra_args,
+                        err
+                    );
+                }
+            }
+        }
+    }
+}
+
 impl<'tcx> layout::HasTyCtxt<'tcx> for RevealAllLayoutCx<'tcx> {
     fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.0
diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 424a0d742d1..5c4991f1fb6 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -129,9 +129,7 @@ pub(crate) fn codegen_constant<'tcx>(
     };
     let const_val = match const_.val {
         ConstKind::Value(const_val) => const_val,
-        ConstKind::Unevaluated(uv)
-            if fx.tcx.is_static(uv.def.did) =>
-        {
+        ConstKind::Unevaluated(uv) if fx.tcx.is_static(uv.def.did) => {
             assert!(uv.substs(fx.tcx).is_empty());
             assert!(uv.promoted.is_none());
 
diff --git a/compiler/rustc_codegen_cranelift/src/pretty_clif.rs b/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
index 05db74745a1..0b80ef1c04e 100644
--- a/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
+++ b/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
@@ -61,9 +61,8 @@ use cranelift_codegen::{
     write::{FuncWriter, PlainWriter},
 };
 
-use rustc_middle::ty::layout::FnAbiExt;
+use rustc_middle::ty::layout::FnAbiOf;
 use rustc_session::config::OutputType;
-use rustc_target::abi::call::FnAbi;
 
 use crate::prelude::*;
 
@@ -81,7 +80,7 @@ impl CommentWriter {
             vec![
                 format!("symbol {}", tcx.symbol_name(instance).name),
                 format!("instance {:?}", instance),
-                format!("abi {:?}", FnAbi::of_instance(&RevealAllLayoutCx(tcx), instance, &[])),
+                format!("abi {:?}", RevealAllLayoutCx(tcx).fn_abi_of_instance(instance, &[])),
                 String::new(),
             ]
         } else {
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 799f9a57e93..8e3aaf56382 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -15,10 +15,12 @@ use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::MemFlags;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
+use rustc_middle::ty::layout::{
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOfHelpers, TyAndLayout,
+};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
-use rustc_target::abi::{self, Align, Size, WrappingRange};
+use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
 use rustc_target::spec::{HasTargetSpec, Target};
 use std::borrow::Cow;
 use std::ffi::CStr;
@@ -97,6 +99,20 @@ impl LayoutOfHelpers<'tcx> for Builder<'_, '_, 'tcx> {
     }
 }
 
+impl FnAbiOfHelpers<'tcx> for Builder<'_, '_, 'tcx> {
+    type FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'_, 'tcx>,
+    ) -> ! {
+        self.cx.handle_fn_abi_err(err, span, fn_abi_request)
+    }
+}
+
 impl Deref for Builder<'_, 'll, 'tcx> {
     type Target = CodegenCx<'ll, 'tcx>;
 
diff --git a/compiler/rustc_codegen_llvm/src/callee.rs b/compiler/rustc_codegen_llvm/src/callee.rs
index bb16c90cd12..1a2aea015b1 100644
--- a/compiler/rustc_codegen_llvm/src/callee.rs
+++ b/compiler/rustc_codegen_llvm/src/callee.rs
@@ -4,7 +4,7 @@
 //! and methods are represented as just a fn ptr and not a full
 //! closure.
 
-use crate::abi::{FnAbi, FnAbiLlvmExt};
+use crate::abi::FnAbiLlvmExt;
 use crate::attributes;
 use crate::context::CodegenCx;
 use crate::llvm;
@@ -12,7 +12,7 @@ use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
 use tracing::debug;
 
-use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
+use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
 use rustc_middle::ty::{self, Instance, TypeFoldable};
 
 /// Codegens a reference to a fn/method item, monomorphizing and
@@ -42,7 +42,7 @@ pub fn get_fn(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) -> &'ll Value
         sym
     );
 
-    let fn_abi = FnAbi::of_instance(cx, instance, &[]);
+    let fn_abi = cx.fn_abi_of_instance(instance, &[]);
 
     let llfn = if let Some(llfn) = cx.get_declared_value(&sym) {
         // Create a fn pointer with the new signature.
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 1d6efdf5f25..f1a2968ce59 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -15,14 +15,19 @@ use rustc_data_structures::base_n;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_middle::mir::mono::CodegenUnit;
-use rustc_middle::ty::layout::{HasParamEnv, LayoutError, LayoutOfHelpers, TyAndLayout};
+use rustc_middle::ty::layout::{
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasParamEnv, LayoutError, LayoutOfHelpers,
+    TyAndLayout,
+};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::config::{CFGuard, CrateType, DebugInfo};
 use rustc_session::Session;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
-use rustc_target::abi::{HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx};
+use rustc_target::abi::{
+    call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
+};
 use rustc_target::spec::{HasTargetSpec, RelocModel, Target, TlsModel};
 use smallvec::SmallVec;
 
@@ -853,3 +858,40 @@ impl LayoutOfHelpers<'tcx> for CodegenCx<'ll, 'tcx> {
         }
     }
 }
+
+impl FnAbiOfHelpers<'tcx> for CodegenCx<'ll, 'tcx> {
+    type FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'_, 'tcx>,
+    ) -> ! {
+        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
+            self.sess().span_fatal(span, &err.to_string())
+        } else {
+            match fn_abi_request {
+                FnAbiRequest::OfFnPtr { sig, extra_args } => {
+                    span_bug!(
+                        span,
+                        "`fn_abi_of_fn_ptr({}, {:?})` failed: {}",
+                        sig,
+                        extra_args,
+                        err
+                    );
+                }
+                FnAbiRequest::OfInstance { instance, extra_args } => {
+                    span_bug!(
+                        span,
+                        "`fn_abi_of_instance({}, {:?})` failed: {}",
+                        instance,
+                        extra_args,
+                        err
+                    );
+                }
+            }
+        }
+    }
+}
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 019bf4a09a7..cc1376278aa 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -1,6 +1,6 @@
 use crate::llvm;
 
-use crate::abi::{Abi, FnAbi};
+use crate::abi::Abi;
 use crate::builder::Builder;
 use crate::common::CodegenCx;
 
@@ -20,7 +20,7 @@ use rustc_middle::mir::coverage::{
     CodeRegion, CounterValueReference, ExpressionOperandId, InjectedExpressionId, Op,
 };
 use rustc_middle::ty;
-use rustc_middle::ty::layout::FnAbiExt;
+use rustc_middle::ty::layout::FnAbiOf;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::Instance;
 
@@ -200,8 +200,7 @@ fn declare_unused_fn(cx: &CodegenCx<'ll, 'tcx>, def_id: &DefId) -> Instance<'tcx
 
     let llfn = cx.declare_fn(
         &tcx.symbol_name(instance).name,
-        &FnAbi::of_fn_ptr(
-            cx,
+        &cx.fn_abi_of_fn_ptr(
             ty::Binder::dummy(tcx.mk_fn_sig(
                 iter::once(tcx.mk_unit()),
                 tcx.mk_unit(),
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
index c2725b83f50..e5fd5bae01b 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
@@ -3,12 +3,11 @@ use super::utils::DIB;
 use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext};
 use rustc_codegen_ssa::traits::*;
 
-use crate::abi::FnAbi;
 use crate::common::CodegenCx;
 use crate::llvm;
 use crate::llvm::debuginfo::{DILocation, DIScope};
 use rustc_middle::mir::{Body, SourceScope};
-use rustc_middle::ty::layout::FnAbiExt;
+use rustc_middle::ty::layout::FnAbiOf;
 use rustc_middle::ty::{self, Instance};
 use rustc_session::config::DebugInfo;
 
@@ -94,7 +93,7 @@ fn make_mir_scope(
                 ty::ParamEnv::reveal_all(),
                 callee,
             );
-            let callee_fn_abi = FnAbi::of_instance(cx, callee, &[]);
+            let callee_fn_abi = cx.fn_abi_of_instance(callee, &[]);
             cx.dbg_scope_fn(callee, &callee_fn_abi, None)
         }
         None => unsafe {
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 1060f911a9e..a046c518e1a 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -15,7 +15,7 @@ use rustc_codegen_ssa::mir::operand::OperandRef;
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::*;
 use rustc_hir as hir;
-use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt, LayoutOf};
+use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf};
 use rustc_middle::ty::{self, Ty};
 use rustc_middle::{bug, span_bug};
 use rustc_span::{sym, symbol::kw, Span, Symbol};
@@ -737,7 +737,7 @@ fn gen_fn<'ll, 'tcx>(
     rust_fn_sig: ty::PolyFnSig<'tcx>,
     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 ) -> (&'ll Type, &'ll Value) {
-    let fn_abi = FnAbi::of_fn_ptr(cx, rust_fn_sig, &[]);
+    let fn_abi = cx.fn_abi_of_fn_ptr(rust_fn_sig, &[]);
     let llty = fn_abi.llvm_type(cx);
     let llfn = cx.declare_fn(name, &fn_abi);
     cx.set_frame_pointer_type(llfn);
diff --git a/compiler/rustc_codegen_llvm/src/mono_item.rs b/compiler/rustc_codegen_llvm/src/mono_item.rs
index 8ba3e870fbb..b0301fa75aa 100644
--- a/compiler/rustc_codegen_llvm/src/mono_item.rs
+++ b/compiler/rustc_codegen_llvm/src/mono_item.rs
@@ -1,4 +1,3 @@
-use crate::abi::FnAbi;
 use crate::attributes;
 use crate::base;
 use crate::context::CodegenCx;
@@ -8,7 +7,7 @@ use rustc_codegen_ssa::traits::*;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 pub use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::mir::mono::{Linkage, Visibility};
-use rustc_middle::ty::layout::{FnAbiExt, LayoutOf};
+use rustc_middle::ty::layout::{FnAbiOf, LayoutOf};
 use rustc_middle::ty::{self, Instance, TypeFoldable};
 use rustc_session::config::CrateType;
 use rustc_target::spec::RelocModel;
@@ -53,7 +52,7 @@ impl PreDefineMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     ) {
         assert!(!instance.substs.needs_infer());
 
-        let fn_abi = FnAbi::of_instance(self, instance, &[]);
+        let fn_abi = self.fn_abi_of_instance(instance, &[]);
         let lldecl = self.declare_fn(symbol_name, &fn_abi);
         unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) };
         let attrs = self.tcx.codegen_fn_attrs(instance.def_id());
diff --git a/compiler/rustc_codegen_llvm/src/type_of.rs b/compiler/rustc_codegen_llvm/src/type_of.rs
index 3e39bf3e995..94ad84aadd8 100644
--- a/compiler/rustc_codegen_llvm/src/type_of.rs
+++ b/compiler/rustc_codegen_llvm/src/type_of.rs
@@ -1,10 +1,9 @@
-use crate::abi::FnAbi;
 use crate::common::*;
 use crate::context::TypeLowering;
 use crate::type_::Type;
 use rustc_codegen_ssa::traits::*;
 use rustc_middle::bug;
-use rustc_middle::ty::layout::{FnAbiExt, LayoutOf, TyAndLayout};
+use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, Ty, TypeFoldable};
 use rustc_target::abi::{Abi, AddressSpace, Align, FieldsShape};
@@ -231,7 +230,7 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
                 ty::Adt(def, _) if def.is_box() => {
                     cx.type_ptr_to(cx.layout_of(self.ty.boxed_ty()).llvm_type(cx))
                 }
-                ty::FnPtr(sig) => cx.fn_ptr_backend_type(&FnAbi::of_fn_ptr(cx, sig, &[])),
+                ty::FnPtr(sig) => cx.fn_ptr_backend_type(&cx.fn_abi_of_fn_ptr(sig, &[])),
                 _ => self.scalar_llvm_type_at(cx, scalar, Size::ZERO),
             };
             cx.scalar_lltypes.borrow_mut().insert(self.ty, llty);
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index c557946afbc..fac72c39b5e 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -14,7 +14,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_index::vec::Idx;
 use rustc_middle::mir::AssertKind;
 use rustc_middle::mir::{self, SwitchTargets};
-use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt, LayoutOf};
+use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
 use rustc_span::source_map::Span;
@@ -337,7 +337,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
                     substs: drop_fn.substs,
                 };
-                let fn_abi = FnAbi::of_instance(&bx, virtual_drop, &[]);
+                let fn_abi = bx.fn_abi_of_instance(virtual_drop, &[]);
                 let vtable = args[1];
                 args = &args[..1];
                 (
@@ -346,7 +346,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     fn_abi,
                 )
             }
-            _ => (bx.get_fn_addr(drop_fn), FnAbi::of_instance(&bx, drop_fn, &[])),
+            _ => (bx.get_fn_addr(drop_fn), bx.fn_abi_of_instance(drop_fn, &[])),
         };
         helper.do_call(
             self,
@@ -433,7 +433,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // Obtain the panic entry point.
         let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
         let instance = ty::Instance::mono(bx.tcx(), def_id);
-        let fn_abi = FnAbi::of_instance(&bx, instance, &[]);
+        let fn_abi = bx.fn_abi_of_instance(instance, &[]);
         let llfn = bx.get_fn_addr(instance);
 
         // Codegen the actual panic invoke/call.
@@ -494,7 +494,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let def_id =
                     common::langcall(bx.tcx(), Some(source_info.span), "", LangItem::Panic);
                 let instance = ty::Instance::mono(bx.tcx(), def_id);
-                let fn_abi = FnAbi::of_instance(bx, instance, &[]);
+                let fn_abi = bx.fn_abi_of_instance(instance, &[]);
                 let llfn = bx.get_fn_addr(instance);
 
                 // Codegen the actual panic invoke/call.
@@ -579,8 +579,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             .collect::<Vec<_>>();
 
         let fn_abi = match instance {
-            Some(instance) => FnAbi::of_instance(&bx, instance, &extra_args),
-            None => FnAbi::of_fn_ptr(&bx, sig, &extra_args),
+            Some(instance) => bx.fn_abi_of_instance(instance, &extra_args),
+            None => bx.fn_abi_of_fn_ptr(sig, &extra_args),
         };
 
         if intrinsic == Some(sym::transmute) {
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 2c7636f1913..3fd9dc08c2b 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -2,7 +2,7 @@ use crate::traits::*;
 use rustc_errors::ErrorReported;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::ErrorHandled;
-use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt, TyAndLayout};
+use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, TyAndLayout};
 use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
 use rustc_target::abi::call::{FnAbi, PassMode};
 
@@ -139,7 +139,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     let mir = cx.tcx().instance_mir(instance.def);
 
-    let fn_abi = FnAbi::of_instance(cx, instance, &[]);
+    let fn_abi = cx.fn_abi_of_instance(instance, &[]);
     debug!("fn_abi: {:?}", fn_abi);
 
     let debug_context = cx.create_function_debug_context(instance, &fn_abi, llfn, &mir);
diff --git a/compiler/rustc_codegen_ssa/src/traits/backend.rs b/compiler/rustc_codegen_ssa/src/traits/backend.rs
index dbb7e1ee8b1..82b79fd0b2a 100644
--- a/compiler/rustc_codegen_ssa/src/traits/backend.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/backend.rs
@@ -8,14 +8,15 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorReported;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
-use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
+use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf, TyAndLayout};
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_session::{
     config::{self, OutputFilenames, PrintRequest},
     Session,
 };
 use rustc_span::symbol::Symbol;
+use rustc_target::abi::call::FnAbi;
 use rustc_target::spec::Target;
 
 pub use rustc_data_structures::sync::MetadataRef;
@@ -38,12 +39,19 @@ pub trait BackendTypes {
 }
 
 pub trait Backend<'tcx>:
-    Sized + BackendTypes + HasTyCtxt<'tcx> + LayoutOf<'tcx, LayoutOfResult = TyAndLayout<'tcx>>
+    Sized
+    + BackendTypes
+    + HasTyCtxt<'tcx>
+    + LayoutOf<'tcx, LayoutOfResult = TyAndLayout<'tcx>>
+    + FnAbiOf<'tcx, FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>>
 {
 }
 
 impl<'tcx, T> Backend<'tcx> for T where
-    Self: BackendTypes + HasTyCtxt<'tcx> + LayoutOf<'tcx, LayoutOfResult = TyAndLayout<'tcx>>
+    Self: BackendTypes
+        + HasTyCtxt<'tcx>
+        + LayoutOf<'tcx, LayoutOfResult = TyAndLayout<'tcx>>
+        + FnAbiOf<'tcx, FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>>
 {
 }
 
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 42ac7705419..04d8eaf7c9f 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -2035,6 +2035,12 @@ impl<'tcx> HasDataLayout for ty::query::TyCtxtAt<'tcx> {
     }
 }
 
+impl<'tcx> HasTargetSpec for ty::query::TyCtxtAt<'tcx> {
+    fn target_spec(&self) -> &Target {
+        &self.sess.target
+    }
+}
+
 impl<'tcx> HasTyCtxt<'tcx> for ty::query::TyCtxtAt<'tcx> {
     #[inline]
     fn tcx(&self) -> TyCtxt<'tcx> {
@@ -2142,10 +2148,10 @@ pub trait LayoutOf<'tcx>: LayoutOfHelpers<'tcx> {
     #[inline]
     fn spanned_layout_of(&self, ty: Ty<'tcx>, span: Span) -> Self::LayoutOfResult {
         let span = if !span.is_dummy() { span } else { self.layout_tcx_at_span() };
+        let tcx = self.tcx().at(span);
+
         MaybeResult::from(
-            self.tcx()
-                .at(span)
-                .layout_of(self.param_env().and(ty))
+            tcx.layout_of(self.param_env().and(ty))
                 .map_err(|err| self.handle_layout_err(err, span, ty)),
         )
     }
@@ -2545,10 +2551,10 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for LayoutError<'tcx> {
 
 impl<'tcx> ty::Instance<'tcx> {
     // NOTE(eddyb) this is private to avoid using it from outside of
-    // `FnAbi::of_instance` - any other uses are either too high-level
+    // `fn_abi_of_instance` - any other uses are either too high-level
     // for `Instance` (e.g. typeck would use `Ty::fn_sig` instead),
     // or should go through `FnAbi` instead, to avoid losing any
-    // adjustments `FnAbi::of_instance` might be performing.
+    // adjustments `fn_abi_of_instance` might be performing.
     fn fn_sig_for_fn_abi(&self, tcx: TyCtxt<'tcx>) -> ty::PolyFnSig<'tcx> {
         // FIXME(davidtwco,eddyb): A `ParamEnv` should be passed through to this function.
         let ty = self.ty(tcx, ty::ParamEnv::reveal_all());
@@ -2801,7 +2807,7 @@ pub fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi) -> Conv {
 }
 
 /// Error produced by attempting to compute or adjust a `FnAbi`.
-enum FnAbiError<'tcx> {
+pub enum FnAbiError<'tcx> {
     /// Error produced by a `layout_of` call, while computing `FnAbi` initially.
     Layout(LayoutError<'tcx>),
 
@@ -2830,125 +2836,124 @@ impl<'tcx> fmt::Display for FnAbiError<'tcx> {
     }
 }
 
-pub trait FnAbiExt<'tcx, C>
-where
-    C: HasTyCtxt<'tcx> + HasParamEnv<'tcx>,
-{
+// FIXME(eddyb) maybe use something like this for an unified `fn_abi_of`, not
+// just for error handling.
+#[derive(Debug)]
+pub enum FnAbiRequest<'a, 'tcx> {
+    OfFnPtr { sig: ty::PolyFnSig<'tcx>, extra_args: &'a [Ty<'tcx>] },
+    OfInstance { instance: ty::Instance<'tcx>, extra_args: &'a [Ty<'tcx>] },
+}
+
+/// Trait for contexts that want to be able to compute `FnAbi`s.
+/// This automatically gives access to `FnAbiOf`, through a blanket `impl`.
+pub trait FnAbiOfHelpers<'tcx>: LayoutOfHelpers<'tcx> {
+    /// The `&FnAbi`-wrapping type (or `&FnAbi` itself), which will be
+    /// returned from `fn_abi_of_*` (see also `handle_fn_abi_err`).
+    type FnAbiOfResult: MaybeResult<&'tcx FnAbi<'tcx, Ty<'tcx>>>;
+
+    /// Helper used for `fn_abi_of_*`, to adapt `tcx.fn_abi_of_*(...)` into a
+    /// `Self::FnAbiOfResult` (which does not need to be a `Result<...>`).
+    ///
+    /// Most `impl`s, which propagate `FnAbiError`s, should simply return `err`,
+    /// but this hook allows e.g. codegen to return only `&FnABi` from its
+    /// `cx.fn_abi_of_*(...)`, without any `Result<...>` around it to deal with
+    /// (and any `FnAbiError`s are turned into fatal errors or ICEs).
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'_, 'tcx>,
+    ) -> <Self::FnAbiOfResult as MaybeResult<&'tcx FnAbi<'tcx, Ty<'tcx>>>>::Error;
+}
+
+/// Blanket extension trait for contexts that can compute `FnAbi`s.
+pub trait FnAbiOf<'tcx>: FnAbiOfHelpers<'tcx> {
     /// Compute a `FnAbi` suitable for indirect calls, i.e. to `fn` pointers.
     ///
-    /// NB: this doesn't handle virtual calls - those should use `FnAbi::of_instance`
+    /// NB: this doesn't handle virtual calls - those should use `fn_abi_of_instance`
     /// instead, where the instance is an `InstanceDef::Virtual`.
-    fn of_fn_ptr(cx: &C, sig: ty::PolyFnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> &'tcx Self;
+    #[inline]
+    fn fn_abi_of_fn_ptr(
+        &self,
+        sig: ty::PolyFnSig<'tcx>,
+        extra_args: &[Ty<'tcx>],
+    ) -> Self::FnAbiOfResult {
+        // FIXME(eddyb) get a better `span` here.
+        let span = self.layout_tcx_at_span();
+        let cx = LayoutCx { tcx: self.tcx().at(span), param_env: self.param_env() };
+
+        MaybeResult::from(
+            cx.fn_abi_new_internal(sig, extra_args, None, CodegenFnAttrFlags::empty(), false)
+                .map_err(|err| {
+                    self.handle_fn_abi_err(err, span, FnAbiRequest::OfFnPtr { sig, extra_args })
+                }),
+        )
+    }
 
     /// Compute a `FnAbi` suitable for declaring/defining an `fn` instance, and for
     /// direct calls to an `fn`.
     ///
     /// NB: that includes virtual calls, which are represented by "direct calls"
     /// to an `InstanceDef::Virtual` instance (of `<dyn Trait as Trait>::fn`).
-    fn of_instance(cx: &C, instance: ty::Instance<'tcx>, extra_args: &[Ty<'tcx>]) -> &'tcx Self;
-}
-
-impl<'tcx, C> FnAbiExt<'tcx, C> for call::FnAbi<'tcx, Ty<'tcx>>
-where
-    C: HasTyCtxt<'tcx> + HasParamEnv<'tcx>,
-{
-    fn of_fn_ptr(cx: &C, sig: ty::PolyFnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> &'tcx Self {
-        call::FnAbi::new_internal(
-            &LayoutCx { tcx: cx.tcx(), param_env: cx.param_env() },
-            sig,
-            extra_args,
-            None,
-            CodegenFnAttrFlags::empty(),
-            false,
-        )
-        .unwrap_or_else(|err| {
-            // FIXME(eddyb) get a better `span` here.
-            let span = DUMMY_SP;
-            if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
-                cx.tcx().sess.span_fatal(span, &err.to_string())
-            } else {
-                span_bug!(span, "`FnAbi::of_fn_ptr({}, {:?})` failed: {}", sig, extra_args, err);
-            }
-        })
-    }
+    #[inline]
+    fn fn_abi_of_instance(
+        &self,
+        instance: ty::Instance<'tcx>,
+        extra_args: &[Ty<'tcx>],
+    ) -> Self::FnAbiOfResult {
+        // FIXME(eddyb) get a better `span` here.
+        let span = self.layout_tcx_at_span();
+        let cx = LayoutCx { tcx: self.tcx().at(span), param_env: self.param_env() };
 
-    fn of_instance(cx: &C, instance: ty::Instance<'tcx>, extra_args: &[Ty<'tcx>]) -> &'tcx Self {
         let sig = instance.fn_sig_for_fn_abi(cx.tcx());
 
         let caller_location = if instance.def.requires_caller_location(cx.tcx()) {
-            Some(cx.tcx().caller_location_ty())
+            Some(cx.tcx.caller_location_ty())
         } else {
             None
         };
 
-        let attrs = cx.tcx().codegen_fn_attrs(instance.def_id()).flags;
+        let attrs = cx.tcx.codegen_fn_attrs(instance.def_id()).flags;
 
-        call::FnAbi::new_internal(
-            &LayoutCx { tcx: cx.tcx(), param_env: cx.param_env() },
-            sig,
-            extra_args,
-            caller_location,
-            attrs,
-            matches!(instance.def, ty::InstanceDef::Virtual(..)),
+        MaybeResult::from(
+            cx.fn_abi_new_internal(
+                sig,
+                extra_args,
+                caller_location,
+                attrs,
+                matches!(instance.def, ty::InstanceDef::Virtual(..)),
+            )
+            .map_err(|err| {
+                // HACK(eddyb) at least for definitions of/calls to `Instance`s,
+                // we can get some kind of span even if one wasn't provided.
+                // However, we don't do this early in order to avoid calling
+                // `def_span` unconditionally (which may have a perf penalty).
+                let span = if !span.is_dummy() { span } else { cx.tcx.def_span(instance.def_id()) };
+                self.handle_fn_abi_err(err, span, FnAbiRequest::OfInstance { instance, extra_args })
+            }),
         )
-        .unwrap_or_else(|err| {
-            // FIXME(eddyb) get a better `span` here.
-            let span = cx.tcx().def_span(instance.def_id());
-            if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
-                cx.tcx().sess.span_fatal(span, &err.to_string())
-            } else {
-                span_bug!(
-                    span,
-                    "`FnAbi::of_instance({}, {:?})` failed: {}",
-                    instance,
-                    extra_args,
-                    err
-                );
-            }
-        })
     }
 }
 
-/// Implementation detail of computing `FnAbi`s, shouldn't be exported.
-// FIXME(eddyb) move this off of being generic on `C: LayoutOf`, and
-// explicitly take `LayoutCx` *or* `TyCtxt` and `ParamEnvAnd<...>`.
-trait FnAbiInternalExt<'tcx, C>
-where
-    C: LayoutOf<'tcx, LayoutOfResult = Result<TyAndLayout<'tcx>, LayoutError<'tcx>>>
-        + HasTargetSpec,
-{
+impl<C: FnAbiOfHelpers<'tcx>> FnAbiOf<'tcx> for C {}
+
+impl<'tcx> LayoutCx<'tcx, ty::query::TyCtxtAt<'tcx>> {
     // FIXME(eddyb) perhaps group the signature/type-containing (or all of them?)
     // arguments of this method, into a separate `struct`.
-    fn new_internal(
-        cx: &C,
+    fn fn_abi_new_internal(
+        &self,
         sig: ty::PolyFnSig<'tcx>,
         extra_args: &[Ty<'tcx>],
         caller_location: Option<Ty<'tcx>>,
         codegen_fn_attr_flags: CodegenFnAttrFlags,
         // FIXME(eddyb) replace this with something typed, like an `enum`.
-        make_self_ptr_thin: bool,
-    ) -> Result<&'tcx Self, FnAbiError<'tcx>>;
-    fn adjust_for_abi(&mut self, cx: &C, abi: SpecAbi) -> Result<(), FnAbiError<'tcx>>;
-}
-
-impl<'tcx, C> FnAbiInternalExt<'tcx, C> for call::FnAbi<'tcx, Ty<'tcx>>
-where
-    C: LayoutOf<'tcx, LayoutOfResult = Result<TyAndLayout<'tcx>, LayoutError<'tcx>>>
-        + HasTargetSpec,
-{
-    fn new_internal(
-        cx: &C,
-        sig: ty::PolyFnSig<'tcx>,
-        extra_args: &[Ty<'tcx>],
-        caller_location: Option<Ty<'tcx>>,
-        codegen_fn_attr_flags: CodegenFnAttrFlags,
         force_thin_self_ptr: bool,
-    ) -> Result<&'tcx Self, FnAbiError<'tcx>> {
+    ) -> Result<&'tcx FnAbi<'tcx, Ty<'tcx>>, FnAbiError<'tcx>> {
         debug!("FnAbi::new_internal({:?}, {:?})", sig, extra_args);
 
-        let sig = cx.tcx().normalize_erasing_late_bound_regions(cx.param_env(), sig);
+        let sig = self.tcx.normalize_erasing_late_bound_regions(self.param_env, sig);
 
-        let conv = conv_from_spec_abi(cx.tcx(), sig.abi);
+        let conv = conv_from_spec_abi(self.tcx(), sig.abi);
 
         let mut inputs = sig.inputs();
         let extra_args = if sig.abi == RustCall {
@@ -2975,7 +2980,7 @@ where
             extra_args.to_vec()
         };
 
-        let target = &cx.tcx().sess.target;
+        let target = &self.tcx.sess.target;
         let target_env_gnu_like = matches!(&target.env[..], "gnu" | "musl");
         let win_x64_gnu = target.os == "windows" && target.arch == "x86_64" && target.env == "gnu";
         let linux_s390x_gnu_like =
@@ -3008,7 +3013,7 @@ where
                 attrs.set(ArgAttribute::NonNull);
             }
 
-            if let Some(pointee) = layout.pointee_info_at(cx, offset) {
+            if let Some(pointee) = layout.pointee_info_at(self, offset) {
                 if let Some(kind) = pointee.safe {
                     attrs.pointee_align = Some(pointee.align);
 
@@ -3055,17 +3060,17 @@ where
         let arg_of = |ty: Ty<'tcx>, arg_idx: Option<usize>| -> Result<_, FnAbiError<'tcx>> {
             let is_return = arg_idx.is_none();
 
-            let layout = cx.layout_of(ty)?;
+            let layout = self.layout_of(ty)?;
             let layout = if force_thin_self_ptr && arg_idx == Some(0) {
                 // Don't pass the vtable, it's not an argument of the virtual fn.
                 // Instead, pass just the data pointer, but give it the type `*const/mut dyn Trait`
                 // or `&/&mut dyn Trait` because this is special-cased elsewhere in codegen
-                make_thin_self_ptr(cx, layout)
+                make_thin_self_ptr(self, layout)
             } else {
                 layout
             };
 
-            let mut arg = ArgAbi::new(cx, layout, |layout, scalar, offset| {
+            let mut arg = ArgAbi::new(self, layout, |layout, scalar, offset| {
                 let mut attrs = ArgAttributes::new();
                 adjust_for_rust_scalar(&mut attrs, scalar, *layout, offset, is_return);
                 attrs
@@ -3102,14 +3107,18 @@ where
             c_variadic: sig.c_variadic,
             fixed_count: inputs.len(),
             conv,
-            can_unwind: fn_can_unwind(cx.tcx(), codegen_fn_attr_flags, sig.abi),
+            can_unwind: fn_can_unwind(self.tcx(), codegen_fn_attr_flags, sig.abi),
         };
-        fn_abi.adjust_for_abi(cx, sig.abi)?;
+        self.fn_abi_adjust_for_abi(&mut fn_abi, sig.abi)?;
         debug!("FnAbi::new_internal = {:?}", fn_abi);
-        Ok(cx.tcx().intern_fn_abi(fn_abi))
+        Ok(self.tcx.intern_fn_abi(fn_abi))
     }
 
-    fn adjust_for_abi(&mut self, cx: &C, abi: SpecAbi) -> Result<(), FnAbiError<'tcx>> {
+    fn fn_abi_adjust_for_abi(
+        &self,
+        fn_abi: &mut FnAbi<'tcx, Ty<'tcx>>,
+        abi: SpecAbi,
+    ) -> Result<(), FnAbiError<'tcx>> {
         if abi == SpecAbi::Unadjusted {
             return Ok(());
         }
@@ -3148,7 +3157,7 @@ where
                     // anyway, we control all calls to it in libstd.
                     Abi::Vector { .. }
                         if abi != SpecAbi::PlatformIntrinsic
-                            && cx.tcx().sess.target.simd_types_indirect =>
+                            && self.tcx.sess.target.simd_types_indirect =>
                     {
                         arg.make_indirect();
                         return;
@@ -3159,7 +3168,7 @@ where
 
                 // Pass and return structures up to 2 pointers in size by value, matching `ScalarPair`.
                 // LLVM will usually pass these in 2 registers, which is more efficient than by-ref.
-                let max_by_val_size = Pointer.size(cx) * 2;
+                let max_by_val_size = Pointer.size(self) * 2;
                 let size = arg.layout.size;
 
                 if arg.layout.is_unsized() || size > max_by_val_size {
@@ -3171,12 +3180,12 @@ where
                     arg.cast_to(Reg { kind: RegKind::Integer, size });
                 }
             };
-            fixup(&mut self.ret);
-            for arg in &mut self.args {
+            fixup(&mut fn_abi.ret);
+            for arg in &mut fn_abi.args {
                 fixup(arg);
             }
         } else {
-            self.adjust_for_foreign_abi(cx, abi)?;
+            fn_abi.adjust_for_foreign_abi(self, abi)?;
         }
 
         Ok(())