diff --git a/Compiler/src/Compiler.jl b/Compiler/src/Compiler.jl
index 9c3581677132e..68eab073b7e2d 100644
--- a/Compiler/src/Compiler.jl
+++ b/Compiler/src/Compiler.jl
@@ -65,7 +65,9 @@ using Base: @_foldable_meta, @_gc_preserve_begin, @_gc_preserve_end, @nospeciali
     structdiff, tls_world_age, unconstrain_vararg_length, unionlen, uniontype_layout,
     uniontypes, unsafe_convert, unwrap_unionall, unwrapva, vect, widen_diagonal,
     _uncompressed_ir, maybe_add_binding_backedge!, datatype_min_ninitialized,
-    partialstruct_init_undefs, fieldcount_noerror, _eval_import, _eval_using
+    partialstruct_init_undefs, fieldcount_noerror, _eval_import, _eval_using,
+    get_ci_mi
+
 using Base.Order
 
 import Base: ==, _topmod, append!, convert, copy, copy!, findall, first, get, get!,
diff --git a/Compiler/src/abstractinterpretation.jl b/Compiler/src/abstractinterpretation.jl
index dae80bec55693..177da3a608eb2 100644
--- a/Compiler/src/abstractinterpretation.jl
+++ b/Compiler/src/abstractinterpretation.jl
@@ -2221,12 +2221,6 @@ function ci_abi(ci::CodeInstance)
     (def::MethodInstance).specTypes
 end
 
-function get_ci_mi(ci::CodeInstance)
-    def = ci.def
-    isa(def, ABIOverride) && return def.def
-    return def::MethodInstance
-end
-
 function abstract_invoke(interp::AbstractInterpreter, arginfo::ArgInfo, si::StmtInfo, sv::AbsIntState)
     argtypes = arginfo.argtypes
     ft′ = argtype_by_index(argtypes, 2)
diff --git a/base/invalidation.jl b/base/invalidation.jl
index bb312931a567b..f26e7968d8a2a 100644
--- a/base/invalidation.jl
+++ b/base/invalidation.jl
@@ -188,7 +188,7 @@ invalidate_code_for_globalref!(gr::GlobalRef, invalidated_bpart::Core.BindingPar
     invalidate_code_for_globalref!(convert(Core.Binding, gr), invalidated_bpart, new_bpart, new_max_world)
 
 function maybe_add_binding_backedge!(b::Core.Binding, edge::Union{Method, CodeInstance})
-    meth = isa(edge, Method) ? edge : Compiler.get_ci_mi(edge).def
+    meth = isa(edge, Method) ? edge : get_ci_mi(edge).def
     ccall(:jl_maybe_add_binding_backedge, Cint, (Any, Any, Any), b, edge, meth)
     return nothing
 end
diff --git a/base/runtime_internals.jl b/base/runtime_internals.jl
index db8fd114a3493..dc78d35a0bc0d 100644
--- a/base/runtime_internals.jl
+++ b/base/runtime_internals.jl
@@ -1478,6 +1478,15 @@ end
 _uncompressed_ir(codeinst::CodeInstance, s::String) =
     ccall(:jl_uncompress_ir, Ref{CodeInfo}, (Any, Any, Any), codeinst.def.def::Method, codeinst, s)
 
+function get_ci_mi(codeinst::CodeInstance)
+    def = codeinst.def
+    if def isa Core.ABIOverride
+        return def.def
+    else
+        return def::MethodInstance
+    end
+end
+
 """
     Base.generating_output([incremental::Bool])::Bool
 
diff --git a/base/stacktraces.jl b/base/stacktraces.jl
index 9e454e430e2b6..653419d2148fb 100644
--- a/base/stacktraces.jl
+++ b/base/stacktraces.jl
@@ -273,8 +273,12 @@ function show_spec_linfo(io::IO, frame::StackFrame)
         if linfo isa Union{MethodInstance, CodeInstance}
             def = frame_method_or_module(frame)
             if def isa Module
-                Base.show_mi(io, linfo, #=from_stackframe=#true)
+                Base.show_mi(io, linfo::MethodInstance, #=from_stackframe=#true)
+            elseif linfo isa CodeInstance && linfo.owner !== nothing
+                show_custom_spec_sig(io, linfo.owner, linfo, frame)
             else
+                # Equivalent to the default implementation of `show_custom_spec_sig`
+                # for `linfo isa CodeInstance`, but saves an extra dynamic dispatch.
                 show_spec_sig(io, def, frame_mi(frame).specTypes)
             end
         else
@@ -284,6 +288,12 @@ function show_spec_linfo(io::IO, frame::StackFrame)
     end
 end
 
+# Can be extended by compiler packages to customize backtrace display of custom code instance frames
+function show_custom_spec_sig(io::IO, @nospecialize(owner), linfo::CodeInstance, frame::StackFrame)
+    mi = get_ci_mi(linfo)
+    return show_spec_sig(io, mi.def, mi.specTypes)
+end
+
 function show_spec_sig(io::IO, m::Method, @nospecialize(sig::Type))
     if get(io, :limit, :false)::Bool
         if !haskey(io, :displaysize)
diff --git a/base/staticdata.jl b/base/staticdata.jl
index 0b65d97750194..928372154653f 100644
--- a/base/staticdata.jl
+++ b/base/staticdata.jl
@@ -3,22 +3,13 @@
 module StaticData
 
 using .Core: CodeInstance, MethodInstance
-using .Base: JLOptions, Compiler, get_world_counter, _methods_by_ftype, get_methodtable
+using .Base: JLOptions, Compiler, get_world_counter, _methods_by_ftype, get_methodtable, get_ci_mi
 
 const WORLD_AGE_REVALIDATION_SENTINEL::UInt = 1
 const _jl_debug_method_invalidation = Ref{Union{Nothing,Vector{Any}}}(nothing)
 debug_method_invalidation(onoff::Bool) =
     _jl_debug_method_invalidation[] = onoff ? Any[] : nothing
 
-function get_ci_mi(codeinst::CodeInstance)
-    def = codeinst.def
-    if def isa Core.ABIOverride
-        return def.def
-    else
-        return def::MethodInstance
-    end
-end
-
 # Restore backedges to external targets
 # `edges` = [caller1, ...], the list of worklist-owned code instances internally
 # `ext_ci_list` = [caller1, ...], the list of worklist-owned code instances externally