diff --git a/src/interface.jl b/src/interface.jl
index 42f839e3..fda6a49f 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -182,7 +182,8 @@ function process_entry!(@nospecialize(job::CompilerJob), mod::LLVM.Module,
     if job.source.kernel
         # pass all bitstypes by value; by default Julia passes aggregates by reference
         # (this improves performance, and is mandated by certain back-ends like SPIR-V).
-        args = classify_arguments(job, eltype(llvmtype(entry)))
+        source_sig = Base.signature_type(job.source.f, job.source.tt)::Type
+        args = classify_arguments(source_sig, eltype(llvmtype(entry)))
         for arg in args
             if arg.cc == BITS_REF
                 attr = if LLVM.version() >= v"12"
diff --git a/src/irgen.jl b/src/irgen.jl
index 4d527aa6..5184df76 100644
--- a/src/irgen.jl
+++ b/src/irgen.jl
@@ -287,10 +287,8 @@ end
     GHOST       # not passed
 end
 
-function classify_arguments(@nospecialize(job::CompilerJob), codegen_ft::LLVM.FunctionType)
-    source_sig = Base.signature_type(job.source.f, job.source.tt)::Type
+function classify_arguments(source_sig::Type, codegen_ft::LLVM.FunctionType)
     source_types = [source_sig.parameters...]
-
     codegen_types = parameters(codegen_ft)
 
     args = []
diff --git a/src/spirv.jl b/src/spirv.jl
index 632b6c51..1ebcfec4 100644
--- a/src/spirv.jl
+++ b/src/spirv.jl
@@ -239,7 +239,8 @@ function wrap_byval(@nospecialize(job::CompilerJob), mod::LLVM.Module, f::LLVM.F
         else
             ft
         end
-        args = classify_arguments(job, orig_ft)
+        source_sig = Base.signature_type(job.source.f, job.source.tt)::Type
+        args = classify_arguments(source_sig, entry_f)
         filter!(args) do arg
             arg.cc != GHOST
         end