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authorJonas Schievink <jonasschievink@gmail.com>2021-02-01 14:29:47 +0100
committerGitHub <noreply@github.com>2021-02-01 14:29:47 +0100
commitb3339ab8283d173ffd4bcbacaf799b50d3dbcdff (patch)
treedb6e26df4f3f761d8665e34c32c92de38adeacf1 /compiler/rustc_codegen_cranelift/src
parent26222272080d179b4f0a5ffe057d07d7341de041 (diff)
parent27855331e8fc27163bac49c9dc10ab0fe6a04d5a (diff)
downloadrust-b3339ab8283d173ffd4bcbacaf799b50d3dbcdff.tar.gz
rust-b3339ab8283d173ffd4bcbacaf799b50d3dbcdff.zip
Rollup merge of #81618 - bjorn3:sync_cg_clif-2021-02-01, r=bjorn3
Sync rustc_codegen_cranelift

The highlight of this sync are abi compatibility with cg_llvm allowing mixing of cg_clif and cg_llvm compiled crates and switching to the x64 cranelift backend based on the new backend framework.

r? ``@ghost``

``@rustbot`` label +A-codegen +A-cranelift +T-compiler
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src')
-rw-r--r--compiler/rustc_codegen_cranelift/src/abi/comments.rs26
-rw-r--r--compiler/rustc_codegen_cranelift/src/abi/mod.rs397
-rw-r--r--compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs421
-rw-r--r--compiler/rustc_codegen_cranelift/src/abi/returning.rs194
-rw-r--r--compiler/rustc_codegen_cranelift/src/analyze.rs11
-rw-r--r--compiler/rustc_codegen_cranelift/src/base.rs15
-rw-r--r--compiler/rustc_codegen_cranelift/src/bin/cg_clif_build_sysroot.rs5
-rw-r--r--compiler/rustc_codegen_cranelift/src/codegen_i128.rs62
-rw-r--r--compiler/rustc_codegen_cranelift/src/common.rs57
-rw-r--r--compiler/rustc_codegen_cranelift/src/driver/aot.rs7
-rw-r--r--compiler/rustc_codegen_cranelift/src/driver/jit.rs12
-rw-r--r--compiler/rustc_codegen_cranelift/src/driver/mod.rs9
-rw-r--r--compiler/rustc_codegen_cranelift/src/lib.rs33
-rw-r--r--compiler/rustc_codegen_cranelift/src/main_shim.rs4
-rw-r--r--compiler/rustc_codegen_cranelift/src/num.rs1
-rw-r--r--compiler/rustc_codegen_cranelift/src/pretty_clif.rs9
-rw-r--r--compiler/rustc_codegen_cranelift/src/value_and_place.rs125
17 files changed, 787 insertions, 601 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/abi/comments.rs b/compiler/rustc_codegen_cranelift/src/abi/comments.rs
index 01073d26e83..9aab45b62e2 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/comments.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/comments.rs
@@ -4,10 +4,10 @@
 use std::borrow::Cow;
 
 use rustc_middle::mir;
+use rustc_target::abi::call::PassMode;
 
 use cranelift_codegen::entity::EntityRef;
 
-use crate::abi::pass_mode::*;
 use crate::prelude::*;
 
 pub(super) fn add_args_header_comment(fx: &mut FunctionCx<'_, '_, impl Module>) {
@@ -21,9 +21,9 @@ pub(super) fn add_arg_comment<'tcx>(
     kind: &str,
     local: Option<mir::Local>,
     local_field: Option<usize>,
-    params: EmptySinglePair<Value>,
-    pass_mode: PassMode,
-    ty: Ty<'tcx>,
+    params: &[Value],
+    arg_abi_mode: PassMode,
+    arg_layout: TyAndLayout<'tcx>,
 ) {
     let local = if let Some(local) = local {
         Cow::Owned(format!("{:?}", local))
@@ -37,12 +37,20 @@ pub(super) fn add_arg_comment<'tcx>(
     };
 
     let params = match params {
-        Empty => Cow::Borrowed("-"),
-        Single(param) => Cow::Owned(format!("= {:?}", param)),
-        Pair(param_a, param_b) => Cow::Owned(format!("= {:?}, {:?}", param_a, param_b)),
+        [] => Cow::Borrowed("-"),
+        [param] => Cow::Owned(format!("= {:?}", param)),
+        [param_a, param_b] => Cow::Owned(format!("= {:?},{:?}", param_a, param_b)),
+        params => Cow::Owned(format!(
+            "= {}",
+            params
+                .iter()
+                .map(ToString::to_string)
+                .collect::<Vec<_>>()
+                .join(",")
+        )),
     };
 
-    let pass_mode = format!("{:?}", pass_mode);
+    let pass_mode = format!("{:?}", arg_abi_mode);
     fx.add_global_comment(format!(
         "{kind:5}{local:>3}{local_field:<5} {params:10} {pass_mode:36} {ty:?}",
         kind = kind,
@@ -50,7 +58,7 @@ pub(super) fn add_arg_comment<'tcx>(
         local_field = local_field,
         params = params,
         pass_mode = pass_mode,
-        ty = ty,
+        ty = arg_layout.ty,
     ));
 }
 
diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 76e1987459f..6a025f2e88a 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -6,199 +6,50 @@ mod pass_mode;
 mod returning;
 
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
+use rustc_middle::ty::layout::FnAbiExt;
+use rustc_target::abi::call::{Conv, FnAbi};
 use rustc_target::spec::abi::Abi;
 
-use cranelift_codegen::ir::{AbiParam, ArgumentPurpose};
+use cranelift_codegen::ir::AbiParam;
+use smallvec::smallvec;
 
 use self::pass_mode::*;
 use crate::prelude::*;
 
 pub(crate) use self::returning::{can_return_to_ssa_var, codegen_return};
 
-// Copied from https://github.com/rust-lang/rust/blob/f52c72948aa1dd718cc1f168d21c91c584c0a662/src/librustc_middle/ty/layout.rs#L2301
-#[rustfmt::skip]
-pub(crate) fn fn_sig_for_fn_abi<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> ty::PolyFnSig<'tcx> {
-    use rustc_middle::ty::subst::Subst;
-
-    // FIXME(davidtwco,eddyb): A `ParamEnv` should be passed through to this function.
-    let ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
-    match *ty.kind() {
-        ty::FnDef(..) => {
-            // HACK(davidtwco,eddyb): This is a workaround for polymorphization considering
-            // parameters unused if they show up in the signature, but not in the `mir::Body`
-            // (i.e. due to being inside a projection that got normalized, see
-            // `src/test/ui/polymorphization/normalized_sig_types.rs`), and codegen not keeping
-            // track of a polymorphization `ParamEnv` to allow normalizing later.
-            let mut sig = match *ty.kind() {
-                ty::FnDef(def_id, substs) => tcx
-                    .normalize_erasing_regions(tcx.param_env(def_id), tcx.fn_sig(def_id))
-                    .subst(tcx, substs),
-                _ => unreachable!(),
-            };
-
-            if let ty::InstanceDef::VtableShim(..) = instance.def {
-                // Modify `fn(self, ...)` to `fn(self: *mut Self, ...)`.
-                sig = sig.map_bound(|mut sig| {
-                    let mut inputs_and_output = sig.inputs_and_output.to_vec();
-                    inputs_and_output[0] = tcx.mk_mut_ptr(inputs_and_output[0]);
-                    sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
-                    sig
-                });
-            }
-            sig
-        }
-        ty::Closure(def_id, substs) => {
-            let sig = substs.as_closure().sig();
-
-            let env_ty = tcx.closure_env_ty(def_id, substs).unwrap();
-            sig.map_bound(|sig| {
-                tcx.mk_fn_sig(
-                    std::iter::once(env_ty.skip_binder()).chain(sig.inputs().iter().cloned()),
-                    sig.output(),
-                    sig.c_variadic,
-                    sig.unsafety,
-                    sig.abi,
-                )
-            })
-        }
-        ty::Generator(_, substs, _) => {
-            let sig = substs.as_generator().poly_sig();
-
-            let env_region = ty::ReLateBound(ty::INNERMOST, ty::BoundRegion { kind: ty::BrEnv });
-            let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
-
-            let pin_did = tcx.require_lang_item(rustc_hir::LangItem::Pin, None);
-            let pin_adt_ref = tcx.adt_def(pin_did);
-            let pin_substs = tcx.intern_substs(&[env_ty.into()]);
-            let env_ty = tcx.mk_adt(pin_adt_ref, pin_substs);
-
-            sig.map_bound(|sig| {
-                let state_did = tcx.require_lang_item(rustc_hir::LangItem::GeneratorState, None);
-                let state_adt_ref = tcx.adt_def(state_did);
-                let state_substs =
-                    tcx.intern_substs(&[sig.yield_ty.into(), sig.return_ty.into()]);
-                let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
-
-                tcx.mk_fn_sig(
-                    [env_ty, sig.resume_ty].iter(),
-                    &ret_ty,
-                    false,
-                    rustc_hir::Unsafety::Normal,
-                    rustc_target::spec::abi::Abi::Rust,
-                )
-            })
-        }
-        _ => bug!("unexpected type {:?} in Instance::fn_sig", ty),
-    }
-}
-
-fn clif_sig_from_fn_sig<'tcx>(
+fn clif_sig_from_fn_abi<'tcx>(
     tcx: TyCtxt<'tcx>,
     triple: &target_lexicon::Triple,
-    sig: FnSig<'tcx>,
-    span: Span,
-    is_vtable_fn: bool,
-    requires_caller_location: bool,
+    fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
 ) -> Signature {
-    let abi = match sig.abi {
-        Abi::System => Abi::C,
-        abi => abi,
-    };
-    let (call_conv, inputs, output): (CallConv, Vec<Ty<'tcx>>, Ty<'tcx>) = match abi {
-        Abi::Rust => (
-            CallConv::triple_default(triple),
-            sig.inputs().to_vec(),
-            sig.output(),
-        ),
-        Abi::C | Abi::Unadjusted => (
-            CallConv::triple_default(triple),
-            sig.inputs().to_vec(),
-            sig.output(),
-        ),
-        Abi::SysV64 => (CallConv::SystemV, sig.inputs().to_vec(), sig.output()),
-        Abi::RustCall => {
-            assert_eq!(sig.inputs().len(), 2);
-            let extra_args = match sig.inputs().last().unwrap().kind() {
-                ty::Tuple(ref tupled_arguments) => tupled_arguments,
-                _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
-            };
-            let mut inputs: Vec<Ty<'tcx>> = vec![sig.inputs()[0]];
-            inputs.extend(extra_args.types());
-            (CallConv::triple_default(triple), inputs, sig.output())
+    let call_conv = match fn_abi.conv {
+        Conv::Rust | Conv::C => CallConv::triple_default(triple),
+        Conv::X86_64SysV => CallConv::SystemV,
+        Conv::X86_64Win64 => CallConv::WindowsFastcall,
+        Conv::ArmAapcs
+        | Conv::Msp430Intr
+        | Conv::PtxKernel
+        | Conv::X86Fastcall
+        | Conv::X86Intr
+        | Conv::X86Stdcall
+        | Conv::X86ThisCall
+        | Conv::X86VectorCall
+        | Conv::AmdGpuKernel
+        | Conv::AvrInterrupt
+        | Conv::AvrNonBlockingInterrupt => {
+            todo!("{:?}", fn_abi.conv)
         }
-        Abi::System => unreachable!(),
-        Abi::RustIntrinsic => (
-            CallConv::triple_default(triple),
-            sig.inputs().to_vec(),
-            sig.output(),
-        ),
-        _ => unimplemented!("unsupported abi {:?}", sig.abi),
     };
-
-    let inputs = inputs
-        .into_iter()
-        .enumerate()
-        .map(|(i, ty)| {
-            let mut layout = tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
-            if i == 0 && is_vtable_fn {
-                // Virtual calls turn their self param into a thin pointer.
-                // See https://github.com/rust-lang/rust/blob/37b6a5e5e82497caf5353d9d856e4eb5d14cbe06/src/librustc/ty/layout.rs#L2519-L2572 for more info
-                layout = tcx
-                    .layout_of(ParamEnv::reveal_all().and(tcx.mk_mut_ptr(tcx.mk_unit())))
-                    .unwrap();
-            }
-            let pass_mode = get_pass_mode(tcx, layout);
-            if abi != Abi::Rust && abi != Abi::RustCall && abi != Abi::RustIntrinsic {
-                match pass_mode {
-                    PassMode::NoPass | PassMode::ByVal(_) => {}
-                    PassMode::ByRef { size: Some(size) } => {
-                        let purpose = ArgumentPurpose::StructArgument(u32::try_from(size.bytes()).expect("struct too big to pass on stack"));
-                        return EmptySinglePair::Single(AbiParam::special(pointer_ty(tcx), purpose)).into_iter();
-                    }
-                    PassMode::ByValPair(_, _) | PassMode::ByRef { size: None } => {
-                        tcx.sess.span_warn(
-                            span,
-                            &format!(
-                                "Argument of type `{:?}` with pass mode `{:?}` is not yet supported \
-                                for non-rust abi `{}`. Calling this function may result in a crash.",
-                                layout.ty,
-                                pass_mode,
-                                abi,
-                            ),
-                        );
-                    }
-                }
-            }
-            pass_mode.get_param_ty(tcx).map(AbiParam::new).into_iter()
-        })
+    let inputs = fn_abi
+        .args
+        .iter()
+        .map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter())
         .flatten();
 
-    let (mut params, returns): (Vec<_>, Vec<_>) = match get_pass_mode(
-        tcx,
-        tcx.layout_of(ParamEnv::reveal_all().and(output)).unwrap(),
-    ) {
-        PassMode::NoPass => (inputs.collect(), vec![]),
-        PassMode::ByVal(ret_ty) => (inputs.collect(), vec![AbiParam::new(ret_ty)]),
-        PassMode::ByValPair(ret_ty_a, ret_ty_b) => (
-            inputs.collect(),
-            vec![AbiParam::new(ret_ty_a), AbiParam::new(ret_ty_b)],
-        ),
-        PassMode::ByRef { size: Some(_) } => {
-            (
-                Some(pointer_ty(tcx)) // First param is place to put return val
-                    .into_iter()
-                    .map(|ty| AbiParam::special(ty, ArgumentPurpose::StructReturn))
-                    .chain(inputs)
-                    .collect(),
-                vec![],
-            )
-        }
-        PassMode::ByRef { size: None } => todo!(),
-    };
-
-    if requires_caller_location {
-        params.push(AbiParam::new(pointer_ty(tcx)));
-    }
+    let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
+    // Sometimes the first param is an pointer to the place where the return value needs to be stored.
+    let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
 
     Signature {
         params,
@@ -207,30 +58,17 @@ fn clif_sig_from_fn_sig<'tcx>(
     }
 }
 
-pub(crate) fn get_function_name_and_sig<'tcx>(
+pub(crate) fn get_function_sig<'tcx>(
     tcx: TyCtxt<'tcx>,
     triple: &target_lexicon::Triple,
     inst: Instance<'tcx>,
-    support_vararg: bool,
-) -> (String, Signature) {
+) -> Signature {
     assert!(!inst.substs.needs_infer());
-    let fn_sig = tcx
-        .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_sig_for_fn_abi(tcx, inst));
-    if fn_sig.c_variadic && !support_vararg {
-        tcx.sess.span_fatal(
-            tcx.def_span(inst.def_id()),
-            "Variadic function definitions are not yet supported",
-        );
-    }
-    let sig = clif_sig_from_fn_sig(
+    clif_sig_from_fn_abi(
         tcx,
         triple,
-        fn_sig,
-        tcx.def_span(inst.def_id()),
-        false,
-        inst.def.requires_caller_location(tcx),
-    );
-    (tcx.symbol_name(inst).name.to_string(), sig)
+        &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]),
+    )
 }
 
 /// Instance must be monomorphized
@@ -239,7 +77,8 @@ pub(crate) fn import_function<'tcx>(
     module: &mut impl Module,
     inst: Instance<'tcx>,
 ) -> FuncId {
-    let (name, sig) = get_function_name_and_sig(tcx, module.isa().triple(), inst, true);
+    let name = tcx.symbol_name(inst).name.to_string();
+    let sig = get_function_sig(tcx, module.isa().triple(), inst);
     module
         .declare_function(&name, Linkage::Import, &sig)
         .unwrap()
@@ -263,13 +102,13 @@ impl<'tcx, M: Module> FunctionCx<'_, 'tcx, M> {
     pub(crate) fn lib_call(
         &mut self,
         name: &str,
-        input_tys: Vec<types::Type>,
-        output_tys: Vec<types::Type>,
+        params: Vec<AbiParam>,
+        returns: Vec<AbiParam>,
         args: &[Value],
     ) -> &[Value] {
         let sig = Signature {
-            params: input_tys.iter().cloned().map(AbiParam::new).collect(),
-            returns: output_tys.iter().cloned().map(AbiParam::new).collect(),
+            params,
+            returns,
             call_conv: CallConv::triple_default(self.triple()),
         };
         let func_id = self
@@ -301,16 +140,18 @@ impl<'tcx, M: Module> FunctionCx<'_, 'tcx, M> {
             .iter()
             .map(|arg| {
                 (
-                    self.clif_type(arg.layout().ty).unwrap(),
+                    AbiParam::new(self.clif_type(arg.layout().ty).unwrap()),
                     arg.load_scalar(self),
                 )
             })
             .unzip();
         let return_layout = self.layout_of(return_ty);
         let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
-            tup.types().map(|ty| self.clif_type(ty).unwrap()).collect()
+            tup.types()
+                .map(|ty| AbiParam::new(self.clif_type(ty).unwrap()))
+                .collect()
         } else {
-            vec![self.clif_type(return_ty).unwrap()]
+            vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
         };
         let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
         match *ret_vals {
@@ -352,12 +193,25 @@ pub(crate) fn codegen_fn_prelude<'tcx>(
     fx: &mut FunctionCx<'_, 'tcx, impl Module>,
     start_block: Block,
 ) {
+    fx.bcx.append_block_params_for_function_params(start_block);
+
+    fx.bcx.switch_to_block(start_block);
+    fx.bcx.ins().nop();
+
     let ssa_analyzed = crate::analyze::analyze(fx);
 
     #[cfg(debug_assertions)]
     self::comments::add_args_header_comment(fx);
 
-    let ret_place = self::returning::codegen_return_param(fx, &ssa_analyzed, start_block);
+    let mut block_params_iter = fx
+        .bcx
+        .func
+        .dfg
+        .block_params(start_block)
+        .to_vec()
+        .into_iter();
+    let ret_place =
+        self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
     assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
 
     // None means pass_mode == NoPass
@@ -366,6 +220,9 @@ pub(crate) fn codegen_fn_prelude<'tcx>(
         Spread(Vec<Option<CValue<'tcx>>>),
     }
 
+    let fn_abi = fx.fn_abi.take().unwrap();
+    let mut arg_abis_iter = fn_abi.args.iter();
+
     let func_params = fx
         .mir
         .args_iter()
@@ -385,14 +242,18 @@ pub(crate) fn codegen_fn_prelude<'tcx>(
                 };
 
                 let mut params = Vec::new();
-                for (i, arg_ty) in tupled_arg_tys.types().enumerate() {
-                    let param = cvalue_for_param(fx, start_block, Some(local), Some(i), arg_ty);
+                for (i, _arg_ty) in tupled_arg_tys.types().enumerate() {
+                    let arg_abi = arg_abis_iter.next().unwrap();
+                    let param =
+                        cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
                     params.push(param);
                 }
 
                 (local, ArgKind::Spread(params), arg_ty)
             } else {
-                let param = cvalue_for_param(fx, start_block, Some(local), None, arg_ty);
+                let arg_abi = arg_abis_iter.next().unwrap();
+                let param =
+                    cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
                 (local, ArgKind::Normal(param), arg_ty)
             }
         })
@@ -401,13 +262,14 @@ pub(crate) fn codegen_fn_prelude<'tcx>(
     assert!(fx.caller_location.is_none());
     if fx.instance.def.requires_caller_location(fx.tcx) {
         // Store caller location for `#[track_caller]`.
-        fx.caller_location = Some(
-            cvalue_for_param(fx, start_block, None, None, fx.tcx.caller_location_ty()).unwrap(),
-        );
+        let arg_abi = arg_abis_iter.next().unwrap();
+        fx.caller_location =
+            Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
     }
 
-    fx.bcx.switch_to_block(start_block);
-    fx.bcx.ins().nop();
+    assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
+    fx.fn_abi = Some(fn_abi);
+    assert!(block_params_iter.next().is_none(), "arg_value left behind");
 
     #[cfg(debug_assertions)]
     self::comments::add_locals_header_comment(fx);
@@ -533,6 +395,21 @@ pub(crate) fn codegen_terminator_call<'tcx>(
         None
     };
 
+    let extra_args = &args[fn_sig.inputs().len()..];
+    let extra_args = extra_args
+        .iter()
+        .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)
+    } else {
+        FnAbi::of_fn_ptr(
+            &RevealAllLayoutCx(fx.tcx),
+            fn_ty.fn_sig(fx.tcx),
+            &extra_args,
+        )
+    };
+
     let is_cold = instance
         .map(|inst| {
             fx.tcx
@@ -570,8 +447,8 @@ pub(crate) fn codegen_terminator_call<'tcx>(
 
     //   | indirect call target
     //   |         | the first argument to be passed
-    //   v         v          v virtual calls are special cased below
-    let (func_ref, first_arg, is_virtual_call) = match instance {
+    //   v         v
+    let (func_ref, first_arg) = match instance {
         // Trait object call
         Some(Instance {
             def: InstanceDef::Virtual(_, idx),
@@ -582,23 +459,19 @@ pub(crate) fn codegen_terminator_call<'tcx>(
                 let nop_inst = fx.bcx.ins().nop();
                 fx.add_comment(
                     nop_inst,
-                    format!(
-                        "virtual call; self arg pass mode: {:?}",
-                        get_pass_mode(fx.tcx, args[0].layout())
-                    ),
+                    format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0],),
                 );
             }
             let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0], idx);
-            (Some(method), Single(ptr), true)
+            (Some(method), smallvec![ptr])
         }
 
         // Normal call
         Some(_) => (
             None,
             args.get(0)
-                .map(|arg| adjust_arg_for_abi(fx, *arg))
-                .unwrap_or(Empty),
-            false,
+                .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
+                .unwrap_or(smallvec![]),
         ),
 
         // Indirect call
@@ -612,23 +485,27 @@ pub(crate) fn codegen_terminator_call<'tcx>(
             (
                 Some(func),
                 args.get(0)
-                    .map(|arg| adjust_arg_for_abi(fx, *arg))
-                    .unwrap_or(Empty),
-                false,
+                    .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
+                    .unwrap_or(smallvec![]),
             )
         }
     };
 
     let ret_place = destination.map(|(place, _)| place);
-    let (call_inst, call_args) =
-        self::returning::codegen_with_call_return_arg(fx, fn_sig, ret_place, |fx, return_ptr| {
+    let (call_inst, call_args) = self::returning::codegen_with_call_return_arg(
+        fx,
+        &fn_abi.ret,
+        ret_place,
+        |fx, return_ptr| {
+            let regular_args_count = args.len();
             let mut call_args: Vec<Value> = return_ptr
                 .into_iter()
                 .chain(first_arg.into_iter())
                 .chain(
                     args.into_iter()
+                        .enumerate()
                         .skip(1)
-                        .map(|arg| adjust_arg_for_abi(fx, arg).into_iter())
+                        .map(|(i, arg)| adjust_arg_for_abi(fx, arg, &fn_abi.args[i]).into_iter())
                         .flatten(),
                 )
                 .collect::<Vec<_>>();
@@ -639,18 +516,17 @@ pub(crate) fn codegen_terminator_call<'tcx>(
             {
                 // Pass the caller location for `#[track_caller]`.
                 let caller_location = fx.get_caller_location(span);
-                call_args.extend(adjust_arg_for_abi(fx, caller_location).into_iter());
+                call_args.extend(
+                    adjust_arg_for_abi(fx, caller_location, &fn_abi.args[regular_args_count])
+                        .into_iter(),
+                );
+                assert_eq!(fn_abi.args.len(), regular_args_count + 1);
+            } else {
+                assert_eq!(fn_abi.args.len(), regular_args_count);
             }
 
             let call_inst = if let Some(func_ref) = func_ref {
-                let sig = clif_sig_from_fn_sig(
-                    fx.tcx,
-                    fx.triple(),
-                    fn_sig,
-                    span,
-                    is_virtual_call,
-                    false, // calls through function pointers never pass the caller location
-                );
+                let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
                 let sig = fx.bcx.import_signature(sig);
                 fx.bcx.ins().call_indirect(sig, func_ref, &call_args)
             } else {
@@ -660,7 +536,8 @@ pub(crate) fn codegen_terminator_call<'tcx>(
             };
 
             (call_inst, call_args)
-        });
+        },
+    );
 
     // FIXME find a cleaner way to support varargs
     if fn_sig.c_variadic {
@@ -701,37 +578,33 @@ pub(crate) fn codegen_drop<'tcx>(
     drop_place: CPlace<'tcx>,
 ) {
     let ty = drop_place.layout().ty;
-    let drop_fn = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
+    let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
 
-    if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
+    if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
         // we don't actually need to drop anything
     } else {
-        let drop_fn_ty = drop_fn.ty(fx.tcx, ParamEnv::reveal_all());
-        let fn_sig = fx.tcx.normalize_erasing_late_bound_regions(
-            ParamEnv::reveal_all(),
-            drop_fn_ty.fn_sig(fx.tcx),
-        );
-        assert_eq!(fn_sig.output(), fx.tcx.mk_unit());
-
         match ty.kind() {
             ty::Dynamic(..) => {
                 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
                 let ptr = ptr.get_addr(fx);
                 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
 
-                let sig = clif_sig_from_fn_sig(
-                    fx.tcx,
-                    fx.triple(),
-                    fn_sig,
-                    span,
-                    true,
-                    false, // `drop_in_place` is never `#[track_caller]`
-                );
+                // FIXME(eddyb) perhaps move some of this logic into
+                // `Instance::resolve_drop_in_place`?
+                let virtual_drop = Instance {
+                    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 sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
                 let sig = fx.bcx.import_signature(sig);
                 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
             }
             _ => {
-                assert!(!matches!(drop_fn.def, InstanceDef::Virtual(_, _)));
+                assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
+
+                let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
 
                 let arg_value = drop_place.place_ref(
                     fx,
@@ -743,17 +616,19 @@ pub(crate) fn codegen_drop<'tcx>(
                         },
                     )),
                 );
-                let arg_value = adjust_arg_for_abi(fx, arg_value);
+                let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0]);
 
                 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
 
-                if drop_fn.def.requires_caller_location(fx.tcx) {
+                if drop_instance.def.requires_caller_location(fx.tcx) {
                     // Pass the caller location for `#[track_caller]`.
                     let caller_location = fx.get_caller_location(span);
-                    call_args.extend(adjust_arg_for_abi(fx, caller_location).into_iter());
+                    call_args.extend(
+                        adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1]).into_iter(),
+                    );
                 }
 
-                let func_ref = fx.get_function_ref(drop_fn);
+                let func_ref = fx.get_function_ref(drop_instance);
                 fx.bcx.ins().call(func_ref, &call_args);
             }
         }
diff --git a/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs b/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
index 8e3682c86c5..1202c23dbe7 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
@@ -1,140 +1,281 @@
 //! Argument passing
 
 use crate::prelude::*;
+use crate::value_and_place::assert_assignable;
 
-pub(super) use EmptySinglePair::*;
+use cranelift_codegen::ir::{ArgumentExtension, ArgumentPurpose};
+use rustc_target::abi::call::{
+    ArgAbi, ArgAttributes, ArgExtension as RustcArgExtension, CastTarget, PassMode, Reg, RegKind,
+};
+use smallvec::{smallvec, SmallVec};
 
-#[derive(Copy, Clone, Debug)]
-pub(super) enum PassMode {
-    NoPass,
-    ByVal(Type),
-    ByValPair(Type, Type),
-    ByRef { size: Option<Size> },
+pub(super) trait ArgAbiExt<'tcx> {
+    fn get_abi_param(&self, tcx: TyCtxt<'tcx>) -> SmallVec<[AbiParam; 2]>;
+    fn get_abi_return(&self, tcx: TyCtxt<'tcx>) -> (Option<AbiParam>, Vec<AbiParam>);
 }
 
-#[derive(Copy, Clone, Debug)]
-pub(super) enum EmptySinglePair<T> {
-    Empty,
-    Single(T),
-    Pair(T, T),
+fn reg_to_abi_param(reg: Reg) -> AbiParam {
+    let clif_ty = match (reg.kind, reg.size.bytes()) {
+        (RegKind::Integer, 1) => types::I8,
+        (RegKind::Integer, 2) => types::I16,
+        (RegKind::Integer, 4) => types::I32,
+        (RegKind::Integer, 8) => types::I64,
+        (RegKind::Integer, 16) => types::I128,
+        (RegKind::Float, 4) => types::F32,
+        (RegKind::Float, 8) => types::F64,
+        (RegKind::Vector, size) => types::I8.by(u16::try_from(size).unwrap()).unwrap(),
+        _ => unreachable!("{:?}", reg),
+    };
+    AbiParam::new(clif_ty)
 }
 
-impl<T> EmptySinglePair<T> {
-    pub(super) fn into_iter(self) -> EmptySinglePairIter<T> {
-        EmptySinglePairIter(self)
-    }
-
-    pub(super) fn map<U>(self, mut f: impl FnMut(T) -> U) -> EmptySinglePair<U> {
-        match self {
-            Empty => Empty,
-            Single(v) => Single(f(v)),
-            Pair(a, b) => Pair(f(a), f(b)),
-        }
+fn apply_arg_attrs_to_abi_param(mut param: AbiParam, arg_attrs: ArgAttributes) -> AbiParam {
+    match arg_attrs.arg_ext {
+        RustcArgExtension::None => {}
+        RustcArgExtension::Zext => param.extension = ArgumentExtension::Uext,
+        RustcArgExtension::Sext => param.extension = ArgumentExtension::Sext,
     }
+    param
 }
 
-pub(super) struct EmptySinglePairIter<T>(EmptySinglePair<T>);
-
-impl<T> Iterator for EmptySinglePairIter<T> {
-    type Item = T;
+fn cast_target_to_abi_params(cast: CastTarget) -> SmallVec<[AbiParam; 2]> {
+    let (rest_count, rem_bytes) = if cast.rest.unit.size.bytes() == 0 {
+        (0, 0)
+    } else {
+        (
+            cast.rest.total.bytes() / cast.rest.unit.size.bytes(),
+            cast.rest.total.bytes() % cast.rest.unit.size.bytes(),
+        )
+    };
 
-    fn next(&mut self) -> Option<T> {
-        match std::mem::replace(&mut self.0, Empty) {
-            Empty => None,
-            Single(v) => Some(v),
-            Pair(a, b) => {
-                self.0 = Single(b);
-                Some(a)
-            }
+    if cast.prefix.iter().all(|x| x.is_none()) {
+        // Simplify to a single unit when there is no prefix and size <= unit size
+        if cast.rest.total <= cast.rest.unit.size {
+            let clif_ty = match (cast.rest.unit.kind, cast.rest.unit.size.bytes()) {
+                (RegKind::Integer, 1) => types::I8,
+                (RegKind::Integer, 2) => types::I16,
+                (RegKind::Integer, 3..=4) => types::I32,
+                (RegKind::Integer, 5..=8) => types::I64,
+                (RegKind::Integer, 9..=16) => types::I128,
+                (RegKind::Float, 4) => types::F32,
+                (RegKind::Float, 8) => types::F64,
+                (RegKind::Vector, size) => types::I8.by(u16::try_from(size).unwrap()).unwrap(),
+                _ => unreachable!("{:?}", cast.rest.unit),
+            };
+            return smallvec![AbiParam::new(clif_ty)];
         }
     }
-}
 
-impl<T: std::fmt::Debug> EmptySinglePair<T> {
-    pub(super) fn assert_single(self) -> T {
-        match self {
-            Single(v) => v,
-            _ => panic!("Called assert_single on {:?}", self),
-        }
-    }
+    // Create list of fields in the main structure
+    let mut args = cast
+        .prefix
+        .iter()
+        .flatten()
+        .map(|&kind| {
+            reg_to_abi_param(Reg {
+                kind,
+                size: cast.prefix_chunk_size,
+            })
+        })
+        .chain((0..rest_count).map(|_| reg_to_abi_param(cast.rest.unit)))
+        .collect::<SmallVec<_>>();
 
-    pub(super) fn assert_pair(self) -> (T, T) {
-        match self {
-            Pair(a, b) => (a, b),
-            _ => panic!("Called assert_pair on {:?}", self),
-        }
+    // Append final integer
+    if rem_bytes != 0 {
+        // Only integers can be really split further.
+        assert_eq!(cast.rest.unit.kind, RegKind::Integer);
+        args.push(reg_to_abi_param(Reg {
+            kind: RegKind::Integer,
+            size: Size::from_bytes(rem_bytes),
+        }));
     }
-}
 
-impl PassMode {
-    pub(super) fn get_param_ty(self, tcx: TyCtxt<'_>) -> EmptySinglePair<Type> {
-        match self {
-            PassMode::NoPass => Empty,
-            PassMode::ByVal(clif_type) => Single(clif_type),
-            PassMode::ByValPair(a, b) => Pair(a, b),
-            PassMode::ByRef { size: Some(_) } => Single(pointer_ty(tcx)),
-            PassMode::ByRef { size: None } => Pair(pointer_ty(tcx), pointer_ty(tcx)),
-        }
-    }
+    args
 }
 
-pub(super) fn get_pass_mode<'tcx>(tcx: TyCtxt<'tcx>, layout: TyAndLayout<'tcx>) -> PassMode {
-    if layout.is_zst() {
-        // WARNING zst arguments must never be passed, as that will break CastKind::ClosureFnPointer
-        PassMode::NoPass
-    } else {
-        match &layout.abi {
-            Abi::Uninhabited => PassMode::NoPass,
-            Abi::Scalar(scalar) => PassMode::ByVal(scalar_to_clif_type(tcx, scalar.clone())),
-            Abi::ScalarPair(a, b) => {
-                let a = scalar_to_clif_type(tcx, a.clone());
-                let b = scalar_to_clif_type(tcx, b.clone());
-                if a == types::I128 && b == types::I128 {
-                    // Returning (i128, i128) by-val-pair would take 4 regs, while only 3 are
-                    // available on x86_64. Cranelift gets confused when too many return params
-                    // are used.
-                    PassMode::ByRef {
-                        size: Some(layout.size),
-                    }
-                } else {
-                    PassMode::ByValPair(a, b)
+impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
+    fn get_abi_param(&self, tcx: TyCtxt<'tcx>) -> SmallVec<[AbiParam; 2]> {
+        match self.mode {
+            PassMode::Ignore => smallvec![],
+            PassMode::Direct(attrs) => match &self.layout.abi {
+                Abi::Scalar(scalar) => {
+                    smallvec![apply_arg_attrs_to_abi_param(
+                        AbiParam::new(scalar_to_clif_type(tcx, scalar.clone())),
+                        attrs
+                    )]
                 }
-            }
-
-            // FIXME implement Vector Abi in a cg_llvm compatible way
-            Abi::Vector { .. } => {
-                if let Some(vector_ty) = crate::intrinsics::clif_vector_type(tcx, layout) {
-                    PassMode::ByVal(vector_ty)
+                Abi::Vector { .. } => {
+                    let vector_ty = crate::intrinsics::clif_vector_type(tcx, self.layout).unwrap();
+                    smallvec![AbiParam::new(vector_ty)]
+                }
+                _ => unreachable!("{:?}", self.layout.abi),
+            },
+            PassMode::Pair(attrs_a, attrs_b) => match &self.layout.abi {
+                Abi::ScalarPair(a, b) => {
+                    let a = scalar_to_clif_type(tcx, a.clone());
+                    let b = scalar_to_clif_type(tcx, b.clone());
+                    smallvec![
+                        apply_arg_attrs_to_abi_param(AbiParam::new(a), attrs_a),
+                        apply_arg_attrs_to_abi_param(AbiParam::new(b), attrs_b),
+                    ]
+                }
+                _ => unreachable!("{:?}", self.layout.abi),
+            },
+            PassMode::Cast(cast) => cast_target_to_abi_params(cast),
+            PassMode::Indirect {
+                attrs,
+                extra_attrs: None,
+                on_stack,
+            } => {
+                if on_stack {
+                    let size = u32::try_from(self.layout.size.bytes()).unwrap();
+                    smallvec![apply_arg_attrs_to_abi_param(
+                        AbiParam::special(pointer_ty(tcx), ArgumentPurpose::StructArgument(size),),
+                        attrs
+                    )]
                 } else {
-                    PassMode::ByRef {
-                        size: Some(layout.size),
-                    }
+                    smallvec![apply_arg_attrs_to_abi_param(
+                        AbiParam::new(pointer_ty(tcx)),
+                        attrs
+                    )]
                 }
             }
+            PassMode::Indirect {
+                attrs,
+                extra_attrs: Some(extra_attrs),
+                on_stack,
+            } => {
+                assert!(!on_stack);
+                smallvec![
+                    apply_arg_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), attrs),
+                    apply_arg_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), extra_attrs),
+                ]
+            }
+        }
+    }
 
-            Abi::Aggregate { sized: true } => PassMode::ByRef {
-                size: Some(layout.size),
+    fn get_abi_return(&self, tcx: TyCtxt<'tcx>) -> (Option<AbiParam>, Vec<AbiParam>) {
+        match self.mode {
+            PassMode::Ignore => (None, vec![]),
+            PassMode::Direct(_) => match &self.layout.abi {
+                Abi::Scalar(scalar) => (
+                    None,
+                    vec![AbiParam::new(scalar_to_clif_type(tcx, scalar.clone()))],
+                ),
+                Abi::Vector { .. } => {
+                    let vector_ty = crate::intrinsics::clif_vector_type(tcx, self.layout).unwrap();
+                    (None, vec![AbiParam::new(vector_ty)])
+                }
+                _ => unreachable!("{:?}", self.layout.abi),
+            },
+            PassMode::Pair(_, _) => match &self.layout.abi {
+                Abi::ScalarPair(a, b) => {
+                    let a = scalar_to_clif_type(tcx, a.clone());
+                    let b = scalar_to_clif_type(tcx, b.clone());
+                    (None, vec![AbiParam::new(a), AbiParam::new(b)])
+                }
+                _ => unreachable!("{:?}", self.layout.abi),
             },
-            Abi::Aggregate { sized: false } => PassMode::ByRef { size: None },
+            PassMode::Cast(cast) => (None, cast_target_to_abi_params(cast).into_iter().collect()),
+            PassMode::Indirect {
+                attrs: _,
+                extra_attrs: None,
+                on_stack,
+            } => {
+                assert!(!on_stack);
+                (
+                    Some(AbiParam::special(
+                        pointer_ty(tcx),
+                        ArgumentPurpose::StructReturn,
+                    )),
+                    vec![],
+                )
+            }
+            PassMode::Indirect {
+                attrs: _,
+                extra_attrs: Some(_),
+                on_stack: _,
+            } => unreachable!("unsized return value"),
         }
     }
 }
 
+pub(super) fn to_casted_value<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
+    arg: CValue<'tcx>,
+    cast: CastTarget,
+) -> SmallVec<[Value; 2]> {
+    let (ptr, meta) = arg.force_stack(fx);
+    assert!(meta.is_none());
+    let mut offset = 0;
+    cast_target_to_abi_params(cast)
+        .into_iter()
+        .map(|param| {
+            let val = ptr
+                .offset_i64(fx, offset)
+                .load(fx, param.value_type, MemFlags::new());
+            offset += i64::from(param.value_type.bytes());
+            val
+        })
+        .collect()
+}
+
+pub(super) fn from_casted_value<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
+    block_params: &[Value],
+    layout: TyAndLayout<'tcx>,
+    cast: CastTarget,
+) -> CValue<'tcx> {
+    let abi_params = cast_target_to_abi_params(cast);
+    let abi_param_size: u32 = abi_params
+        .iter()
+        .map(|param| param.value_type.bytes())
+        .sum();
+    let layout_size = u32::try_from(layout.size.bytes()).unwrap();
+    let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
+        kind: StackSlotKind::ExplicitSlot,
+        // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to
+        // specify stack slot alignment.
+        // Stack slot size may be bigger for for example `[u8; 3]` which is packed into an `i32`.
+        // It may also be smaller for example when the type is a wrapper around an integer with a
+        // larger alignment than the integer.
+        size: (std::cmp::max(abi_param_size, layout_size) + 15) / 16 * 16,
+        offset: None,
+    });
+    let ptr = Pointer::new(fx.bcx.ins().stack_addr(pointer_ty(fx.tcx), stack_slot, 0));
+    let mut offset = 0;
+    let mut block_params_iter = block_params.into_iter().copied();
+    for param in abi_params {
+        let val = ptr.offset_i64(fx, offset).store(
+            fx,
+            block_params_iter.next().unwrap(),
+            MemFlags::new(),
+        );
+        offset += i64::from(param.value_type.bytes());
+        val
+    }
+    assert_eq!(block_params_iter.next(), None, "Leftover block param");
+    CValue::by_ref(ptr, layout)
+}
+
 /// Get a set of values to be passed as function arguments.
 pub(super) fn adjust_arg_for_abi<'tcx>(
     fx: &mut FunctionCx<'_, 'tcx, impl Module>,
     arg: CValue<'tcx>,
-) -> EmptySinglePair<Value> {
-    match get_pass_mode(fx.tcx, arg.layout()) {
-        PassMode::NoPass => Empty,
-        PassMode::ByVal(_) => Single(arg.load_scalar(fx)),
-        PassMode::ByValPair(_, _) => {
+    arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
+) -> SmallVec<[Value; 2]> {
+    assert_assignable(fx, arg.layout().ty, arg_abi.layout.ty);
+    match arg_abi.mode {
+        PassMode::Ignore => smallvec![],
+        PassMode::Direct(_) => smallvec![arg.load_scalar(fx)],
+        PassMode::Pair(_, _) => {
             let (a, b) = arg.load_scalar_pair(fx);
-            Pair(a, b)
+            smallvec![a, b]
         }
-        PassMode::ByRef { size: _ } => match arg.force_stack(fx) {
-            (ptr, None) => Single(ptr.get_addr(fx)),
-            (ptr, Some(meta)) => Pair(ptr.get_addr(fx), meta),
+        PassMode::Cast(cast) => to_casted_value(fx, arg, cast),
+        PassMode::Indirect { .. } => match arg.force_stack(fx) {
+            (ptr, None) => smallvec![ptr.get_addr(fx)],
+            (ptr, Some(meta)) => smallvec![ptr.get_addr(fx), meta],
         },
     }
 }
@@ -143,20 +284,23 @@ pub(super) fn adjust_arg_for_abi<'tcx>(
 /// as necessary.
 pub(super) fn cvalue_for_param<'tcx>(
     fx: &mut FunctionCx<'_, 'tcx, impl Module>,
-    start_block: Block,
     #[cfg_attr(not(debug_assertions), allow(unused_variables))] local: Option<mir::Local>,
     #[cfg_attr(not(debug_assertions), allow(unused_variables))] local_field: Option<usize>,
-    arg_ty: Ty<'tcx>,
+    arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
+    block_params_iter: &mut impl Iterator<Item = Value>,
 ) -> Option<CValue<'tcx>> {
-    let layout = fx.layout_of(arg_ty);
-    let pass_mode = get_pass_mode(fx.tcx, layout);
-
-    if let PassMode::NoPass = pass_mode {
-        return None;
-    }
-
-    let clif_types = pass_mode.get_param_ty(fx.tcx);
-    let block_params = clif_types.map(|t| fx.bcx.append_block_param(start_block, t));
+    let block_params = arg_abi
+        .get_abi_param(fx.tcx)
+        .into_iter()
+        .map(|abi_param| {
+            let block_param = block_params_iter.next().unwrap();
+            assert_eq!(
+                fx.bcx.func.dfg.value_type(block_param),
+                abi_param.value_type
+            );
+            block_param
+        })
+        .collect::<SmallVec<[_; 2]>>();
 
     #[cfg(debug_assertions)]
     crate::abi::comments::add_arg_comment(
@@ -164,25 +308,48 @@ pub(super) fn cvalue_for_param<'tcx>(
         "arg",
         local,
         local_field,
-        block_params,
-        pass_mode,
-        arg_ty,
+        &block_params,
+        arg_abi.mode,
+        arg_abi.layout,
     );
 
-    match pass_mode {
-        PassMode::NoPass => unreachable!(),
-        PassMode::ByVal(_) => Some(CValue::by_val(block_params.assert_single(), layout)),
-        PassMode::ByValPair(_, _) => {
-            let (a, b) = block_params.assert_pair();
-            Some(CValue::by_val_pair(a, b, layout))
+    match arg_abi.mode {
+        PassMode::Ignore => None,
+        PassMode::Direct(_) => {
+            assert_eq!(block_params.len(), 1, "{:?}", block_params);
+            Some(CValue::by_val(block_params[0], arg_abi.layout))
+        }
+        PassMode::Pair(_, _) => {
+            assert_eq!(block_params.len(), 2, "{:?}", block_params);
+            Some(CValue::by_val_pair(
+                block_params[0],
+                block_params[1],
+                arg_abi.layout,
+            ))
+        }
+        PassMode::Cast(cast) => Some(from_casted_value(fx, &block_params, arg_abi.layout, cast)),
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: None,
+            on_stack: _,
+        } => {
+            assert_eq!(block_params.len(), 1, "{:?}", block_params);
+            Some(CValue::by_ref(
+                Pointer::new(block_params[0]),
+                arg_abi.layout,
+            ))
         }
-        PassMode::ByRef { size: Some(_) } => Some(CValue::by_ref(
-            Pointer::new(block_params.assert_single()),
-            layout,
-        )),
-        PassMode::ByRef { size: None } => {
-            let (ptr, meta) = block_params.assert_pair();
-            Some(CValue::by_ref_unsized(Pointer::new(ptr), meta, layout))
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: Some(_),
+            on_stack: _,
+        } => {
+            assert_eq!(block_params.len(), 2, "{:?}", block_params);
+            Some(CValue::by_ref_unsized(
+                Pointer::new(block_params[0]),
+                block_params[1],
+                arg_abi.layout,
+            ))
         }
     }
 }
diff --git a/compiler/rustc_codegen_cranelift/src/abi/returning.rs b/compiler/rustc_codegen_cranelift/src/abi/returning.rs
index f6d40c880d0..a382963bf1e 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/returning.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/returning.rs
@@ -1,21 +1,57 @@
 //! Return value handling
 
-use crate::abi::pass_mode::*;
 use crate::prelude::*;
 
-fn return_layout<'a, 'tcx>(fx: &mut FunctionCx<'a, 'tcx, impl Module>) -> TyAndLayout<'tcx> {
-    fx.layout_of(fx.monomorphize(&fx.mir.local_decls[RETURN_PLACE].ty))
-}
+use rustc_middle::ty::layout::FnAbiExt;
+use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
+use smallvec::{smallvec, SmallVec};
 
 /// Can the given type be returned into an ssa var or does it need to be returned on the stack.
 pub(crate) fn can_return_to_ssa_var<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    dest_layout: TyAndLayout<'tcx>,
+    fx: &FunctionCx<'_, 'tcx, impl Module>,
+    func: &mir::Operand<'tcx>,
+    args: &[mir::Operand<'tcx>],
 ) -> bool {
-    match get_pass_mode(tcx, dest_layout) {
-        PassMode::NoPass | PassMode::ByVal(_) | PassMode::ByValPair(_, _) => true,
-        // FIXME Make it possible to return ByRef to an ssa var.
-        PassMode::ByRef { size: _ } => false,
+    let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
+    let fn_sig = fx
+        .tcx
+        .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
+
+    // Handle special calls like instrinsics and empty drop glue.
+    let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
+        let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
+            .unwrap()
+            .unwrap()
+            .polymorphize(fx.tcx);
+
+        match instance.def {
+            InstanceDef::Intrinsic(_) | InstanceDef::DropGlue(_, _) => {
+                return true;
+            }
+            _ => Some(instance),
+        }
+    } else {
+        None
+    };
+
+    let extra_args = &args[fn_sig.inputs().len()..];
+    let extra_args = extra_args
+        .iter()
+        .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)
+    } else {
+        FnAbi::of_fn_ptr(
+            &RevealAllLayoutCx(fx.tcx),
+            fn_ty.fn_sig(fx.tcx),
+            &extra_args,
+        )
+    };
+    match fn_abi.ret.mode {
+        PassMode::Ignore | PassMode::Direct(_) | PassMode::Pair(_, _) => true,
+        // FIXME Make it possible to return Cast and Indirect to an ssa var.
+        PassMode::Cast(_) | PassMode::Indirect { .. } => false,
     }
 }
 
@@ -24,27 +60,45 @@ pub(crate) fn can_return_to_ssa_var<'tcx>(
 pub(super) fn codegen_return_param<'tcx>(
     fx: &mut FunctionCx<'_, 'tcx, impl Module>,
     ssa_analyzed: &rustc_index::vec::IndexVec<Local, crate::analyze::SsaKind>,
-    start_block: Block,
+    block_params_iter: &mut impl Iterator<Item = Value>,
 ) -> CPlace<'tcx> {
-    let ret_layout = return_layout(fx);
-    let ret_pass_mode = get_pass_mode(fx.tcx, ret_layout);
-    let (ret_place, ret_param) = match ret_pass_mode {
-        PassMode::NoPass => (CPlace::no_place(ret_layout), Empty),
-        PassMode::ByVal(_) | PassMode::ByValPair(_, _) => {
+    let (ret_place, ret_param): (_, SmallVec<[_; 2]>) = match fx.fn_abi.as_ref().unwrap().ret.mode {
+        PassMode::Ignore => (
+            CPlace::no_place(fx.fn_abi.as_ref().unwrap().ret.layout),
+            smallvec![],
+        ),
+        PassMode::Direct(_) | PassMode::Pair(_, _) | PassMode::Cast(_) => {
             let is_ssa = ssa_analyzed[RETURN_PLACE] == crate::analyze::SsaKind::Ssa;
             (
-                super::make_local_place(fx, RETURN_PLACE, ret_layout, is_ssa),
-                Empty,
+                super::make_local_place(
+                    fx,
+                    RETURN_PLACE,
+                    fx.fn_abi.as_ref().unwrap().ret.layout,
+                    is_ssa,
+                ),
+                smallvec![],
             )
         }
-        PassMode::ByRef { size: Some(_) } => {
-            let ret_param = fx.bcx.append_block_param(start_block, fx.pointer_type);
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: None,
+            on_stack: _,
+        } => {
+            let ret_param = block_params_iter.next().unwrap();
+            assert_eq!(fx.bcx.func.dfg.value_type(ret_param), pointer_ty(fx.tcx));
             (
-                CPlace::for_ptr(Pointer::new(ret_param), ret_layout),
-                Single(ret_param),
+                CPlace::for_ptr(
+                    Pointer::new(ret_param),
+                    fx.fn_abi.as_ref().unwrap().ret.layout,
+                ),
+                smallvec![ret_param],
             )
         }
-        PassMode::ByRef { size: None } => todo!(),
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: Some(_),
+            on_stack: _,
+        } => unreachable!("unsized return value"),
     };
 
     #[cfg(not(debug_assertions))]
@@ -56,9 +110,9 @@ pub(super) fn codegen_return_param<'tcx>(
         "ret",
         Some(RETURN_PLACE),
         None,
-        ret_param,
-        ret_pass_mode,
-        ret_layout.ty,
+        &ret_param,
+        fx.fn_abi.as_ref().unwrap().ret.mode,
+        fx.fn_abi.as_ref().unwrap().ret.layout,
     );
 
     ret_place
@@ -68,42 +122,71 @@ pub(super) fn codegen_return_param<'tcx>(
 /// returns the call return value(s) if any are written to the correct place.
 pub(super) fn codegen_with_call_return_arg<'tcx, M: Module, T>(
     fx: &mut FunctionCx<'_, 'tcx, M>,
-    fn_sig: FnSig<'tcx>,
+    ret_arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
     ret_place: Option<CPlace<'tcx>>,
     f: impl FnOnce(&mut FunctionCx<'_, 'tcx, M>, Option<Value>) -> (Inst, T),
 ) -> (Inst, T) {
-    let ret_layout = fx.layout_of(fn_sig.output());
-
-    let output_pass_mode = get_pass_mode(fx.tcx, ret_layout);
-    let return_ptr = match output_pass_mode {
-        PassMode::NoPass => None,
-        PassMode::ByRef { size: Some(_) } => match ret_place {
+    let return_ptr = match ret_arg_abi.mode {
+        PassMode::Ignore => None,
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: None,
+            on_stack: _,
+        } => match ret_place {
             Some(ret_place) => Some(ret_place.to_ptr().get_addr(fx)),
             None => Some(fx.bcx.ins().iconst(fx.pointer_type, 43)), // FIXME allocate temp stack slot
         },
-        PassMode::ByRef { size: None } => todo!(),
-        PassMode::ByVal(_) | PassMode::ByValPair(_, _) => None,
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: Some(_),
+            on_stack: _,
+        } => unreachable!("unsized return value"),
+        PassMode::Direct(_) | PassMode::Pair(_, _) | PassMode::Cast(_) => None,
     };
 
     let (call_inst, meta) = f(fx, return_ptr);
 
-    match output_pass_mode {
-        PassMode::NoPass => {}
-        PassMode::ByVal(_) => {
+    match ret_arg_abi.mode {
+        PassMode::Ignore => {}
+        PassMode::Direct(_) => {
             if let Some(ret_place) = ret_place {
                 let ret_val = fx.bcx.inst_results(call_inst)[0];
-                ret_place.write_cvalue(fx, CValue::by_val(ret_val, ret_layout));
+                ret_place.write_cvalue(fx, CValue::by_val(ret_val, ret_arg_abi.layout));
             }
         }
-        PassMode::ByValPair(_, _) => {
+        PassMode::Pair(_, _) => {
             if let Some(ret_place) = ret_place {
                 let ret_val_a = fx.bcx.inst_results(call_inst)[0];
                 let ret_val_b = fx.bcx.inst_results(call_inst)[1];
-                ret_place.write_cvalue(fx, CValue::by_val_pair(ret_val_a, ret_val_b, ret_layout));
+                ret_place.write_cvalue(
+                    fx,
+                    CValue::by_val_pair(ret_val_a, ret_val_b, ret_arg_abi.layout),
+                );
             }
         }
-        PassMode::ByRef { size: Some(_) } => {}
-        PassMode::ByRef { size: None } => todo!(),
+        PassMode::Cast(cast) => {
+            if let Some(ret_place) = ret_place {
+                let results = fx
+                    .bcx
+                    .inst_results(call_inst)
+                    .into_iter()
+                    .copied()
+                    .collect::<SmallVec<[Value; 2]>>();
+                let result =
+                    super::pass_mode::from_casted_value(fx, &results, ret_place.layout(), cast);
+                ret_place.write_cvalue(fx, result);
+            }
+        }
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: None,
+            on_stack: _,
+        } => {}
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: Some(_),
+            on_stack: _,
+        } => unreachable!("unsized return value"),
     }
 
     (call_inst, meta)
@@ -111,20 +194,35 @@ pub(super) fn codegen_with_call_return_arg<'tcx, M: Module, T>(
 
 /// Codegen a return instruction with the right return value(s) if any.
 pub(crate) fn codegen_return(fx: &mut FunctionCx<'_, '_, impl Module>) {
-    match get_pass_mode(fx.tcx, return_layout(fx)) {
-        PassMode::NoPass | PassMode::ByRef { size: Some(_) } => {
+    match fx.fn_abi.as_ref().unwrap().ret.mode {
+        PassMode::Ignore
+        | PassMode::Indirect {
+            attrs: _,
+            extra_attrs: None,
+            on_stack: _,
+        } => {
             fx.bcx.ins().return_(&[]);
         }
-        PassMode::ByRef { size: None } => todo!(),
-        PassMode::ByVal(_) => {
+        PassMode::Indirect {
+            attrs: _,
+            extra_attrs: Some(_),
+            on_stack: _,
+        } => unreachable!("unsized return value"),
+        PassMode::Direct(_) => {
             let place = fx.get_local_place(RETURN_PLACE);
             let ret_val = place.to_cvalue(fx).load_scalar(fx);
             fx.bcx.ins().return_(&[ret_val]);
         }
-        PassMode::ByValPair(_, _) => {
+        PassMode::Pair(_, _) => {
             let place = fx.get_local_place(RETURN_PLACE);
             let (ret_val_a, ret_val_b) = place.to_cvalue(fx).load_scalar_pair(fx);
             fx.bcx.ins().return_(&[ret_val_a, ret_val_b]);
         }
+        PassMode::Cast(cast) => {
+            let place = fx.get_local_place(RETURN_PLACE);
+            let ret_val = place.to_cvalue(fx);
+            let ret_vals = super::pass_mode::to_casted_value(fx, ret_val, cast);
+            fx.bcx.ins().return_(&ret_vals);
+        }
     }
 }
diff --git a/compiler/rustc_codegen_cranelift/src/analyze.rs b/compiler/rustc_codegen_cranelift/src/analyze.rs
index adf5c7ac4fe..62fbcfe3f7a 100644
--- a/compiler/rustc_codegen_cranelift/src/analyze.rs
+++ b/compiler/rustc_codegen_cranelift/src/analyze.rs
@@ -40,11 +40,14 @@ pub(crate) fn analyze(fx: &FunctionCx<'_, '_, impl Module>) -> IndexVec<Local, S
         }
 
         match &bb.terminator().kind {
-            TerminatorKind::Call { destination, .. } => {
+            TerminatorKind::Call {
+                destination,
+                func,
+                args,
+                ..
+            } => {
                 if let Some((dest_place, _dest_bb)) = destination {
-                    let dest_layout = fx
-                        .layout_of(fx.monomorphize(&dest_place.ty(&fx.mir.local_decls, fx.tcx).ty));
-                    if !crate::abi::can_return_to_ssa_var(fx.tcx, dest_layout) {
+                    if !crate::abi::can_return_to_ssa_var(fx, func, args) {
                         not_ssa(&mut flag_map, dest_place.local)
                     }
                 }
diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
index 34c9561d676..4842628a99d 100644
--- a/compiler/rustc_codegen_cranelift/src/base.rs
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -2,6 +2,8 @@
 
 use rustc_index::vec::IndexVec;
 use rustc_middle::ty::adjustment::PointerCast;
+use rustc_middle::ty::layout::FnAbiExt;
+use rustc_target::abi::call::FnAbi;
 
 use crate::prelude::*;
 
@@ -19,7 +21,8 @@ pub(crate) fn codegen_fn<'tcx>(
     let mir = tcx.instance_mir(instance.def);
 
     // Declare function
-    let (name, sig) = get_function_name_and_sig(tcx, cx.module.isa().triple(), instance, false);
+    let name = tcx.symbol_name(instance).name.to_string();
+    let sig = get_function_sig(tcx, cx.module.isa().triple(), instance);
     let func_id = cx.module.declare_function(&name, linkage, &sig).unwrap();
 
     cx.cached_context.clear();
@@ -50,6 +53,7 @@ pub(crate) fn codegen_fn<'tcx>(
 
         instance,
         mir,
+        fn_abi: Some(FnAbi::of_instance(&RevealAllLayoutCx(tcx), instance, &[])),
 
         bcx,
         block_map,
@@ -117,6 +121,9 @@ pub(crate) fn codegen_fn<'tcx>(
     context.compute_domtree();
     context.eliminate_unreachable_code(cx.module.isa()).unwrap();
     context.dce(cx.module.isa()).unwrap();
+    // Some Cranelift optimizations expect the domtree to not yet be computed and as such don't
+    // invalidate it when it would change.
+    context.domtree.clear();
 
     context.want_disasm = crate::pretty_clif::should_write_ir(tcx);
 
@@ -1053,7 +1060,11 @@ pub(crate) fn codegen_panic_inner<'tcx>(
 
     fx.lib_call(
         &*symbol_name,
-        vec![fx.pointer_type, fx.pointer_type, fx.pointer_type],
+        vec![
+            AbiParam::new(fx.pointer_type),
+            AbiParam::new(fx.pointer_type),
+            AbiParam::new(fx.pointer_type),
+        ],
         vec![],
         args,
     );
diff --git a/compiler/rustc_codegen_cranelift/src/bin/cg_clif_build_sysroot.rs b/compiler/rustc_codegen_cranelift/src/bin/cg_clif_build_sysroot.rs
index 8ee4cd46c94..83e5dc6e672 100644
--- a/compiler/rustc_codegen_cranelift/src/bin/cg_clif_build_sysroot.rs
+++ b/compiler/rustc_codegen_cranelift/src/bin/cg_clif_build_sysroot.rs
@@ -53,10 +53,7 @@ impl rustc_driver::Callbacks for CraneliftPassesCallbacks {
                 .unwrap()
                 .parent()
                 .unwrap()
-                .parent()
-                .unwrap()
-                .join("build_sysroot")
-                .join("sysroot"),
+                .to_owned(),
         );
     }
 }
diff --git a/compiler/rustc_codegen_cranelift/src/codegen_i128.rs b/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
index d6a38bdafc9..866ba90e4ae 100644
--- a/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
+++ b/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
@@ -1,5 +1,7 @@
 //! Replaces 128-bit operators with lang item calls where necessary
 
+use cranelift_codegen::ir::ArgumentPurpose;
+
 use crate::prelude::*;
 
 pub(crate) fn maybe_codegen<'tcx>(
@@ -24,41 +26,41 @@ pub(crate) fn maybe_codegen<'tcx>(
             None
         }
         BinOp::Add | BinOp::Sub if !checked => None,
-        BinOp::Add => {
-            let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
-            return Some(if is_signed {
-                fx.easy_call("__rust_i128_addo", &[lhs, rhs], out_ty)
+        BinOp::Mul if !checked => {
+            let val_ty = if is_signed {
+                fx.tcx.types.i128
             } else {
-                fx.easy_call("__rust_u128_addo", &[lhs, rhs], out_ty)
-            });
+                fx.tcx.types.u128
+            };
+            Some(fx.easy_call("__multi3", &[lhs, rhs], val_ty))
         }
-        BinOp::Sub => {
+        BinOp::Add | BinOp::Sub | BinOp::Mul => {
+            assert!(checked);
             let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
-            return Some(if is_signed {
-                fx.easy_call("__rust_i128_subo", &[lhs, rhs], out_ty)
-            } else {
-                fx.easy_call("__rust_u128_subo", &[lhs, rhs], out_ty)
-            });
-        }
-        BinOp::Offset => unreachable!("offset should only be used on pointers, not 128bit ints"),
-        BinOp::Mul => {
-            let res = if checked {
-                let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
-                if is_signed {
-                    fx.easy_call("__rust_i128_mulo", &[lhs, rhs], out_ty)
-                } else {
-                    fx.easy_call("__rust_u128_mulo", &[lhs, rhs], out_ty)
-                }
-            } else {
-                let val_ty = if is_signed {
-                    fx.tcx.types.i128
-                } else {
-                    fx.tcx.types.u128
-                };
-                fx.easy_call("__multi3", &[lhs, rhs], val_ty)
+            let out_place = CPlace::new_stack_slot(fx, fx.layout_of(out_ty));
+            let param_types = vec![
+                AbiParam::special(pointer_ty(fx.tcx), ArgumentPurpose::StructReturn),
+                AbiParam::new(types::I128),
+                AbiParam::new(types::I128),
+            ];
+            let args = [
+                out_place.to_ptr().get_addr(fx),
+                lhs.load_scalar(fx),
+                rhs.load_scalar(fx),
+            ];
+            let name = match (bin_op, is_signed) {
+                (BinOp::Add, false) => "__rust_u128_addo",
+                (BinOp::Add, true) => "__rust_i128_addo",
+                (BinOp::Sub, false) => "__rust_u128_subo",
+                (BinOp::Sub, true) => "__rust_i128_subo",
+                (BinOp::Mul, false) => "__rust_u128_mulo",
+                (BinOp::Mul, true) => "__rust_i128_mulo",
+                _ => unreachable!(),
             };
-            Some(res)
+            fx.lib_call(name, param_types, vec![], &args);
+            Some(out_place.to_cvalue(fx))
         }
+        BinOp::Offset => unreachable!("offset should only be used on pointers, not 128bit ints"),
         BinOp::Div => {
             assert!(!checked);
             if is_signed {
diff --git a/compiler/rustc_codegen_cranelift/src/common.rs b/compiler/rustc_codegen_cranelift/src/common.rs
index 1485d4451b8..fbee84e09f7 100644
--- a/compiler/rustc_codegen_cranelift/src/common.rs
+++ b/compiler/rustc_codegen_cranelift/src/common.rs
@@ -1,4 +1,5 @@
 use rustc_index::vec::IndexVec;
+use rustc_target::abi::call::FnAbi;
 use rustc_target::abi::{Integer, Primitive};
 use rustc_target::spec::{HasTargetSpec, Target};
 
@@ -294,6 +295,7 @@ pub(crate) struct FunctionCx<'clif, 'tcx, M: Module> {
 
     pub(crate) instance: Instance<'tcx>,
     pub(crate) mir: &'tcx Body<'tcx>,
+    pub(crate) fn_abi: Option<FnAbi<'tcx, Ty<'tcx>>>,
 
     pub(crate) bcx: FunctionBuilder<'clif>,
     pub(crate) block_map: IndexVec<BasicBlock, Block>,
@@ -319,16 +321,7 @@ impl<'tcx, M: Module> LayoutOf for FunctionCx<'_, 'tcx, M> {
     type TyAndLayout = TyAndLayout<'tcx>;
 
     fn layout_of(&self, ty: Ty<'tcx>) -> TyAndLayout<'tcx> {
-        assert!(!ty.still_further_specializable());
-        self.tcx
-            .layout_of(ParamEnv::reveal_all().and(&ty))
-            .unwrap_or_else(|e| {
-                if let layout::LayoutError::SizeOverflow(_) = e {
-                    self.tcx.sess.fatal(&e.to_string())
-                } else {
-                    bug!("failed to get layout for `{}`: {}", ty, e)
-                }
-            })
+        RevealAllLayoutCx(self.tcx).layout_of(ty)
     }
 }
 
@@ -442,3 +435,47 @@ impl<'tcx, M: Module> FunctionCx<'_, 'tcx, M> {
         self.bcx.ins().global_value(self.pointer_type, local_msg_id)
     }
 }
+
+pub(crate) struct RevealAllLayoutCx<'tcx>(pub(crate) TyCtxt<'tcx>);
+
+impl<'tcx> LayoutOf for RevealAllLayoutCx<'tcx> {
+    type Ty = Ty<'tcx>;
+    type TyAndLayout = TyAndLayout<'tcx>;
+
+    fn layout_of(&self, ty: Ty<'tcx>) -> TyAndLayout<'tcx> {
+        assert!(!ty.still_further_specializable());
+        self.0
+            .layout_of(ParamEnv::reveal_all().and(&ty))
+            .unwrap_or_else(|e| {
+                if let layout::LayoutError::SizeOverflow(_) = e {
+                    self.0.sess.fatal(&e.to_string())
+                } else {
+                    bug!("failed to get layout for `{}`: {}", ty, e)
+                }
+            })
+    }
+}
+
+impl<'tcx> layout::HasTyCtxt<'tcx> for RevealAllLayoutCx<'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
+        self.0
+    }
+}
+
+impl<'tcx> rustc_target::abi::HasDataLayout for RevealAllLayoutCx<'tcx> {
+    fn data_layout(&self) -> &rustc_target::abi::TargetDataLayout {
+        &self.0.data_layout
+    }
+}
+
+impl<'tcx> layout::HasParamEnv<'tcx> for RevealAllLayoutCx<'tcx> {
+    fn param_env(&self) -> ParamEnv<'tcx> {
+        ParamEnv::reveal_all()
+    }
+}
+
+impl<'tcx> HasTargetSpec for RevealAllLayoutCx<'tcx> {
+    fn target_spec(&self) -> &Target {
+        &self.0.sess.target
+    }
+}
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index 16f9bfc9918..df89883f0bb 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -281,9 +281,6 @@ pub(super) fn run_aot(
         None
     };
 
-    rustc_incremental::assert_dep_graph(tcx);
-    rustc_incremental::save_dep_graph(tcx);
-
     let metadata_module = if need_metadata_module {
         let _timer = tcx.prof.generic_activity("codegen crate metadata");
         let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
@@ -322,10 +319,6 @@ pub(super) fn run_aot(
         None
     };
 
-    if tcx.sess.opts.output_types.should_codegen() {
-        rustc_incremental::assert_module_sources::assert_module_sources(tcx);
-    }
-
     Box::new((
         CodegenResults {
             crate_name: tcx.crate_name(LOCAL_CRATE),
diff --git a/compiler/rustc_codegen_cranelift/src/driver/jit.rs b/compiler/rustc_codegen_cranelift/src/driver/jit.rs
index 9a42c675cc1..2d14ff2c022 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/jit.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/jit.rs
@@ -156,12 +156,8 @@ extern "C" fn __clif_jit_fn(instance_ptr: *const Instance<'static>) -> *const u8
             let jit_module = jit_module.as_mut().unwrap();
             let mut cx = crate::CodegenCx::new(tcx, jit_module, false, false);
 
-            let (name, sig) = crate::abi::get_function_name_and_sig(
-                tcx,
-                cx.module.isa().triple(),
-                instance,
-                true,
-            );
+            let name = tcx.symbol_name(instance).name.to_string();
+            let sig = crate::abi::get_function_sig(tcx, cx.module.isa().triple(), instance);
             let func_id = cx
                 .module
                 .declare_function(&name, Linkage::Export, &sig)
@@ -246,8 +242,8 @@ pub(super) fn codegen_shim<'tcx>(cx: &mut CodegenCx<'tcx, impl Module>, inst: In
 
     let pointer_type = cx.module.target_config().pointer_type();
 
-    let (name, sig) =
-        crate::abi::get_function_name_and_sig(tcx, cx.module.isa().triple(), inst, true);
+    let name = tcx.symbol_name(inst).name.to_string();
+    let sig = crate::abi::get_function_sig(tcx, cx.module.isa().triple(), inst);
     let func_id = cx
         .module
         .declare_function(&name, Linkage::Export, &sig)
diff --git a/compiler/rustc_codegen_cranelift/src/driver/mod.rs b/compiler/rustc_codegen_cranelift/src/driver/mod.rs
index 9f4ea9a3865..2497f9dfdfb 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/mod.rs
@@ -50,12 +50,9 @@ fn predefine_mono_items<'tcx>(
         for &(mono_item, (linkage, visibility)) in mono_items {
             match mono_item {
                 MonoItem::Fn(instance) => {
-                    let (name, sig) = get_function_name_and_sig(
-                        cx.tcx,
-                        cx.module.isa().triple(),
-                        instance,
-                        false,
-                    );
+                    let name = cx.tcx.symbol_name(instance).name.to_string();
+                    let _inst_guard = crate::PrintOnPanic(|| format!("{:?} {}", instance, name));
+                    let sig = get_function_sig(cx.tcx, cx.module.isa().triple(), instance);
                     let linkage = crate::linkage::get_clif_linkage(mono_item, linkage, visibility);
                     cx.module.declare_function(&name, linkage, &sig).unwrap();
                 }
diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs
index f31c58b92e4..170750461ca 100644
--- a/compiler/rustc_codegen_cranelift/src/lib.rs
+++ b/compiler/rustc_codegen_cranelift/src/lib.rs
@@ -27,7 +27,6 @@ extern crate rustc_incremental;
 extern crate rustc_index;
 extern crate rustc_session;
 extern crate rustc_span;
-extern crate rustc_symbol_mangling;
 extern crate rustc_target;
 
 // This prevents duplicating functions and statics that are already part of the host rustc process.
@@ -90,7 +89,8 @@ mod prelude {
     pub(crate) use rustc_middle::mir::{self, *};
     pub(crate) use rustc_middle::ty::layout::{self, TyAndLayout};
     pub(crate) use rustc_middle::ty::{
-        self, FloatTy, FnSig, Instance, InstanceDef, IntTy, ParamEnv, Ty, TyCtxt, TypeAndMut, TypeFoldable, UintTy,
+        self, FloatTy, Instance, InstanceDef, IntTy, ParamEnv, Ty, TyCtxt, TypeAndMut,
+        TypeFoldable, UintTy,
     };
     pub(crate) use rustc_target::abi::{Abi, LayoutOf, Scalar, Size, VariantIdx};
 
@@ -256,8 +256,6 @@ impl CodegenBackend for CraneliftCodegenBackend {
         };
         let res = driver::codegen_crate(tcx, metadata, need_metadata_module, config);
 
-        rustc_symbol_mangling::test::report_symbol_names(tcx);
-
         res
     }
 
@@ -279,18 +277,14 @@ impl CodegenBackend for CraneliftCodegenBackend {
     ) -> Result<(), ErrorReported> {
         use rustc_codegen_ssa::back::link::link_binary;
 
-        let _timer = sess.prof.generic_activity("link_crate");
-
-        sess.time("linking", || {
-            let target_cpu = crate::target_triple(sess).to_string();
-            link_binary::<crate::archive::ArArchiveBuilder<'_>>(
-                sess,
-                &codegen_results,
-                outputs,
-                &codegen_results.crate_name.as_str(),
-                &target_cpu,
-            );
-        });
+        let target_cpu = crate::target_triple(sess).to_string();
+        link_binary::<crate::archive::ArArchiveBuilder<'_>>(
+            sess,
+            &codegen_results,
+            outputs,
+            &codegen_results.crate_name.as_str(),
+            &target_cpu,
+        );
 
         Ok(())
     }
@@ -345,7 +339,12 @@ fn build_isa(sess: &Session) -> Box<dyn isa::TargetIsa + 'static> {
 
     let flags = settings::Flags::new(flags_builder);
 
-    let mut isa_builder = cranelift_codegen::isa::lookup(target_triple).unwrap();
+    let variant = if cfg!(feature = "oldbe") {
+        cranelift_codegen::isa::BackendVariant::Legacy
+    } else {
+        cranelift_codegen::isa::BackendVariant::MachInst
+    };
+    let mut isa_builder = cranelift_codegen::isa::lookup_variant(target_triple, variant).unwrap();
     // Don't use "haswell", as it implies `has_lzcnt`.macOS CI is still at Ivy Bridge EP, so `lzcnt`
     // is interpreted as `bsr`.
     isa_builder.enable("nehalem").unwrap();
diff --git a/compiler/rustc_codegen_cranelift/src/main_shim.rs b/compiler/rustc_codegen_cranelift/src/main_shim.rs
index 6c472e6774f..b193cea877d 100644
--- a/compiler/rustc_codegen_cranelift/src/main_shim.rs
+++ b/compiler/rustc_codegen_cranelift/src/main_shim.rs
@@ -69,8 +69,8 @@ pub(crate) fn maybe_create_entry_wrapper(
 
         let instance = Instance::mono(tcx, rust_main_def_id).polymorphize(tcx);
 
-        let (main_name, main_sig) =
-            get_function_name_and_sig(tcx, m.isa().triple(), instance, false);
+        let main_name = tcx.symbol_name(instance).name.to_string();
+        let main_sig = get_function_sig(tcx, m.isa().triple(), instance);
         let main_func_id = m
             .declare_function(&main_name, Linkage::Import, &main_sig)
             .unwrap();
diff --git a/compiler/rustc_codegen_cranelift/src/num.rs b/compiler/rustc_codegen_cranelift/src/num.rs
index 41f4a9b9662..d1d2b3b872a 100644
--- a/compiler/rustc_codegen_cranelift/src/num.rs
+++ b/compiler/rustc_codegen_cranelift/src/num.rs
@@ -280,7 +280,6 @@ pub(crate) fn codegen_checked_int_binop<'tcx>(
                     (val, fx.bcx.ins().bor(has_underflow, has_overflow))
                 }
                 types::I64 => {
-                    //let val = fx.easy_call("__mulodi4", &[lhs, rhs, overflow_ptr], types::I64);
                     let val = fx.bcx.ins().imul(lhs, rhs);
                     let has_overflow = if !signed {
                         let val_hi = fx.bcx.ins().umulhi(lhs, rhs);
diff --git a/compiler/rustc_codegen_cranelift/src/pretty_clif.rs b/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
index 22c94fec82f..f4a15ab12d5 100644
--- a/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
+++ b/compiler/rustc_codegen_cranelift/src/pretty_clif.rs
@@ -61,7 +61,9 @@ use cranelift_codegen::{
     write::{FuncWriter, PlainWriter},
 };
 
+use rustc_middle::ty::layout::FnAbiExt;
 use rustc_session::config::OutputType;
+use rustc_target::abi::call::FnAbi;
 
 use crate::prelude::*;
 
@@ -78,11 +80,8 @@ impl CommentWriter {
                 format!("symbol {}", tcx.symbol_name(instance).name),
                 format!("instance {:?}", instance),
                 format!(
-                    "sig {:?}",
-                    tcx.normalize_erasing_late_bound_regions(
-                        ParamEnv::reveal_all(),
-                        crate::abi::fn_sig_for_fn_abi(tcx, instance)
-                    )
+                    "abi {:?}",
+                    FnAbi::of_instance(&RevealAllLayoutCx(tcx), instance, &[])
                 ),
                 String::new(),
             ]
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
index 5bcb11fd515..765604e0f98 100644
--- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs
+++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
@@ -334,7 +334,9 @@ impl<'tcx> CPlace<'tcx> {
 
         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
             kind: StackSlotKind::ExplicitSlot,
-            size: u32::try_from(layout.size.bytes()).unwrap(),
+            // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to
+            // specify stack slot alignment.
+            size: (u32::try_from(layout.size.bytes()).unwrap() + 15) / 16 * 16,
             offset: None,
         });
         CPlace {
@@ -450,64 +452,6 @@ impl<'tcx> CPlace<'tcx> {
         fx: &mut FunctionCx<'_, 'tcx, impl Module>,
         from: CValue<'tcx>,
     ) {
-        fn assert_assignable<'tcx>(
-            fx: &FunctionCx<'_, 'tcx, impl Module>,
-            from_ty: Ty<'tcx>,
-            to_ty: Ty<'tcx>,
-        ) {
-            match (from_ty.kind(), to_ty.kind()) {
-                (ty::Ref(_, a, _), ty::Ref(_, b, _))
-                | (
-                    ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }),
-                    ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }),
-                ) => {
-                    assert_assignable(fx, a, b);
-                }
-                (ty::FnPtr(_), ty::FnPtr(_)) => {
-                    let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
-                        ParamEnv::reveal_all(),
-                        from_ty.fn_sig(fx.tcx),
-                    );
-                    let to_sig = fx.tcx.normalize_erasing_late_bound_regions(
-                        ParamEnv::reveal_all(),
-                        to_ty.fn_sig(fx.tcx),
-                    );
-                    assert_eq!(
-                        from_sig, to_sig,
-                        "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
-                        from_sig, to_sig, fx,
-                    );
-                    // fn(&T) -> for<'l> fn(&'l T) is allowed
-                }
-                (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
-                    for (from, to) in from_traits.iter().zip(to_traits) {
-                        let from = fx
-                            .tcx
-                            .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from);
-                        let to = fx
-                            .tcx
-                            .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to);
-                        assert_eq!(
-                            from, to,
-                            "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
-                            from_traits, to_traits, fx,
-                        );
-                    }
-                    // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
-                }
-                _ => {
-                    assert_eq!(
-                        from_ty,
-                        to_ty,
-                        "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
-                        from_ty,
-                        to_ty,
-                        fx,
-                    );
-                }
-            }
-        }
-
         assert_assignable(fx, from.layout().ty, self.layout().ty);
 
         self.write_cvalue_maybe_transmute(fx, from, "write_cvalue");
@@ -556,7 +500,9 @@ impl<'tcx> CPlace<'tcx> {
                     // FIXME do something more efficient for transmutes between vectors and integers.
                     let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
                         kind: StackSlotKind::ExplicitSlot,
-                        size: src_ty.bytes(),
+                        // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to
+                        // specify stack slot alignment.
+                        size: (src_ty.bytes() + 15) / 16 * 16,
                         offset: None,
                     });
                     let ptr = Pointer::stack_slot(stack_slot);
@@ -794,3 +740,62 @@ impl<'tcx> CPlace<'tcx> {
         }
     }
 }
+
+#[track_caller]
+pub(crate) fn assert_assignable<'tcx>(
+    fx: &FunctionCx<'_, 'tcx, impl Module>,
+    from_ty: Ty<'tcx>,
+    to_ty: Ty<'tcx>,
+) {
+    match (from_ty.kind(), to_ty.kind()) {
+        (ty::Ref(_, a, _), ty::Ref(_, b, _))
+        | (
+            ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }),
+            ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }),
+        ) => {
+            assert_assignable(fx, a, b);
+        }
+        (ty::Ref(_, a, _), ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }))
+        | (ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }), ty::Ref(_, b, _)) => {
+            assert_assignable(fx, a, b);
+        }
+        (ty::FnPtr(_), ty::FnPtr(_)) => {
+            let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
+                ParamEnv::reveal_all(),
+                from_ty.fn_sig(fx.tcx),
+            );
+            let to_sig = fx
+                .tcx
+                .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to_ty.fn_sig(fx.tcx));
+            assert_eq!(
+                from_sig, to_sig,
+                "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
+                from_sig, to_sig, fx,
+            );
+            // fn(&T) -> for<'l> fn(&'l T) is allowed
+        }
+        (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
+            for (from, to) in from_traits.iter().zip(to_traits) {
+                let from = fx
+                    .tcx
+                    .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from);
+                let to = fx
+                    .tcx
+                    .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to);
+                assert_eq!(
+                    from, to,
+                    "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
+                    from_traits, to_traits, fx,
+                );
+            }
+            // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
+        }
+        _ => {
+            assert_eq!(
+                from_ty, to_ty,
+                "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
+                from_ty, to_ty, fx,
+            );
+        }
+    }
+}