diff --git a/src/abi/comments.rs b/src/abi/comments.rs
new file mode 100644
index 00000000000..674449cf06d
--- /dev/null
+++ b/src/abi/comments.rs
@@ -0,0 +1,94 @@
+use std::borrow::Cow;
+
+use rustc::mir;
+
+use crate::prelude::*;
+use crate::abi::pass_mode::*;
+
+pub fn add_local_header_comment(fx: &mut FunctionCx<impl Backend>) {
+    fx.add_global_comment(format!(
+        "msg   loc.idx    param    pass mode                            ssa flags  ty"
+    ));
+}
+
+pub fn add_arg_comment<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+    msg: &str,
+    local: mir::Local,
+    local_field: Option<usize>,
+    params: EmptySinglePair<Value>,
+    pass_mode: PassMode,
+    ssa: crate::analyze::Flags,
+    ty: Ty<'tcx>,
+) {
+    let local_field = if let Some(local_field) = local_field {
+        Cow::Owned(format!(".{}", local_field))
+    } else {
+        Cow::Borrowed("")
+    };
+    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)),
+    };
+    let pass_mode = format!("{:?}", pass_mode);
+    fx.add_global_comment(format!(
+        "{msg:5}{local:>3}{local_field:<5} {params:10} {pass_mode:36} {ssa:10} {ty:?}",
+        msg = msg,
+        local = format!("{:?}", local),
+        local_field = local_field,
+        params = params,
+        pass_mode = pass_mode,
+        ssa = format!("{:?}", ssa),
+        ty = ty,
+    ));
+}
+
+pub fn add_local_place_comments<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+    place: CPlace<'tcx>,
+    local: Local,
+) {
+    let TyLayout { ty, details } = place.layout();
+    let ty::layout::LayoutDetails {
+        size,
+        align,
+        abi: _,
+        variants: _,
+        fields: _,
+        largest_niche: _,
+    } = details;
+    match *place.inner() {
+        CPlaceInner::Var(var) => {
+            assert_eq!(local, var);
+            fx.add_global_comment(format!(
+                "ssa   {:?}: {:?} size={} align={}, {}",
+                local,
+                ty,
+                size.bytes(),
+                align.abi.bytes(),
+                align.pref.bytes(),
+            ));
+        }
+        CPlaceInner::Stack(stack_slot) => fx.add_entity_comment(
+            stack_slot,
+            format!(
+                "{:?}: {:?} size={} align={},{}",
+                local,
+                ty,
+                size.bytes(),
+                align.abi.bytes(),
+                align.pref.bytes(),
+            ),
+        ),
+        CPlaceInner::NoPlace => fx.add_global_comment(format!(
+            "zst   {:?}: {:?} size={} align={}, {}",
+            local,
+            ty,
+            size.bytes(),
+            align.abi.bytes(),
+            align.pref.bytes(),
+        )),
+        CPlaceInner::Addr(_, _) => unreachable!(),
+    }
+}
diff --git a/src/abi/mod.rs b/src/abi/mod.rs
index dc6bac0e426..512b1b68ad9 100644
--- a/src/abi/mod.rs
+++ b/src/abi/mod.rs
@@ -1,8 +1,8 @@
+#[cfg(debug_assertions)]
+mod comments;
 mod returning;
 mod pass_mode;
 
-use std::borrow::Cow;
-
 use rustc_target::spec::abi::Abi;
 
 use crate::prelude::*;
@@ -193,47 +193,6 @@ impl<'tcx, B: Backend + 'static> FunctionCx<'_, 'tcx, B> {
     }
 }
 
-#[cfg(debug_assertions)]
-fn add_arg_comment<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
-    msg: &str,
-    local: mir::Local,
-    local_field: Option<usize>,
-    params: EmptySinglePair<Value>,
-    pass_mode: PassMode,
-    ssa: crate::analyze::Flags,
-    ty: Ty<'tcx>,
-) {
-    let local_field = if let Some(local_field) = local_field {
-        Cow::Owned(format!(".{}", local_field))
-    } else {
-        Cow::Borrowed("")
-    };
-    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)),
-    };
-    let pass_mode = format!("{:?}", pass_mode);
-    fx.add_global_comment(format!(
-        "{msg:5} {local:>3}{local_field:<5} {params:10} {pass_mode:36} {ssa:10} {ty:?}",
-        msg = msg,
-        local = format!("{:?}", local),
-        local_field = local_field,
-        params = params,
-        pass_mode = pass_mode,
-        ssa = format!("{:?}", ssa),
-        ty = ty,
-    ));
-}
-
-#[cfg(debug_assertions)]
-fn add_local_header_comment(fx: &mut FunctionCx<impl Backend>) {
-    fx.add_global_comment(format!(
-        "msg   loc.idx    param    pass mode                            ssa flags  ty"
-    ));
-}
-
 fn local_place<'tcx>(
     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
     local: Local,
@@ -243,46 +202,12 @@ fn local_place<'tcx>(
     let place = if is_ssa {
         CPlace::new_var(fx, local, layout)
     } else {
-        let place = CPlace::new_stack_slot(fx, layout.ty);
-
-        #[cfg(debug_assertions)]
-        {
-            let TyLayout { ty, details } = layout;
-            let ty::layout::LayoutDetails {
-                size,
-                align,
-                abi: _,
-                variants: _,
-                fields: _,
-                largest_niche: _,
-            } = details;
-            match *place.inner() {
-                CPlaceInner::Stack(stack_slot) => fx.add_entity_comment(
-                    stack_slot,
-                    format!(
-                        "{:?}: {:?} size={} align={},{}",
-                        local,
-                        ty,
-                        size.bytes(),
-                        align.abi.bytes(),
-                        align.pref.bytes(),
-                    ),
-                ),
-                CPlaceInner::NoPlace => fx.add_global_comment(format!(
-                    "zst    {:?}: {:?} size={} align={}, {}",
-                    local,
-                    ty,
-                    size.bytes(),
-                    align.abi.bytes(),
-                    align.pref.bytes(),
-                )),
-                _ => unreachable!(),
-            }
-        }
-
-        place
+        CPlace::new_stack_slot(fx, layout.ty)
     };
 
+    #[cfg(debug_assertions)]
+    self::comments::add_local_place_comments(fx, place, local);
+
     let prev_place = fx.local_map.insert(local, place);
     debug_assert!(prev_place.is_none());
     fx.local_map[&local]
@@ -295,10 +220,7 @@ pub fn codegen_fn_prelude(
     let ssa_analyzed = crate::analyze::analyze(fx);
 
     #[cfg(debug_assertions)]
-    {
-        fx.add_global_comment(format!("ssa {:?}", ssa_analyzed));
-        add_local_header_comment(fx);
-    }
+    self::comments::add_local_header_comment(fx);
 
     self::returning::codegen_return_param(fx, &ssa_analyzed, start_ebb);
 
diff --git a/src/abi/pass_mode.rs b/src/abi/pass_mode.rs
index 4608562e993..f5c91338842 100644
--- a/src/abi/pass_mode.rs
+++ b/src/abi/pass_mode.rs
@@ -145,7 +145,7 @@ pub fn cvalue_for_param<'tcx>(
     let ebb_params = clif_types.map(|t| fx.bcx.append_ebb_param(start_ebb, t));
 
     #[cfg(debug_assertions)]
-    super::add_arg_comment(
+    crate::abi::comments::add_arg_comment(
         fx,
         "arg",
         local,
diff --git a/src/abi/returning.rs b/src/abi/returning.rs
index 45ba48d7c4f..465127e9b71 100644
--- a/src/abi/returning.rs
+++ b/src/abi/returning.rs
@@ -37,18 +37,16 @@ pub fn codegen_return_param(
     };
 
     #[cfg(debug_assertions)]
-    {
-        super::add_arg_comment(
-            fx,
-            "ret",
-            RETURN_PLACE,
-            None,
-            ret_param,
-            output_pass_mode,
-            ssa_analyzed[&RETURN_PLACE],
-            ret_layout.ty,
-        );
-    }
+    crate::abi::comments::add_arg_comment(
+        fx,
+        "ret",
+        RETURN_PLACE,
+        None,
+        ret_param,
+        output_pass_mode,
+        ssa_analyzed[&RETURN_PLACE],
+        ret_layout.ty,
+    );
 }
 
 pub fn codegen_with_call_return_arg<'tcx, B: Backend, T>(