From cf0270cb4c5b098773a98e2a688906944ab9661e Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Sun, 19 Aug 2018 17:38:11 +0200
Subject: [PATCH] Add internal function mapping subr index to function

* libguile/gsubr.h:
* libguile/gsubr.c (scm_subr_function_by_index): New internal function.
  (scm_subr_function): Use new function.
---
 libguile/gsubr.c | 10 ++++++++--
 libguile/gsubr.h |  1 +
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/libguile/gsubr.c b/libguile/gsubr.c
index 2384776e0..b99cc67ca 100644
--- a/libguile/gsubr.c
+++ b/libguile/gsubr.c
@@ -441,12 +441,18 @@ scm_i_primitive_name (const uint32_t *code)
 }
 
 scm_t_subr
-scm_subr_function (SCM subr)
+scm_subr_function_by_index (uint32_t idx)
 {
-  uint32_t idx = primitive_subr_idx (SCM_PROGRAM_CODE (subr));
   if (idx == NOT_A_SUBR_CALL)
     abort ();
   return subrs[idx];
+}  
+
+scm_t_subr
+scm_subr_function (SCM subr)
+{
+  uint32_t idx = primitive_subr_idx (SCM_PROGRAM_CODE (subr));
+  return scm_subr_function_by_index (idx);
 }
 
 SCM
diff --git a/libguile/gsubr.h b/libguile/gsubr.h
index 63c2a7603..91a1104b6 100644
--- a/libguile/gsubr.h
+++ b/libguile/gsubr.h
@@ -57,6 +57,7 @@ SCM_INTERNAL uintptr_t scm_i_primitive_call_ip (SCM subr);
 SCM_INTERNAL SCM scm_i_primitive_name (const uint32_t *code);
 
 SCM_API scm_t_subr scm_subr_function (SCM subr);
+SCM_INTERNAL scm_t_subr scm_subr_function_by_index (uint32_t subr_idx);
 SCM_API SCM scm_subr_name (SCM subr);
 
 SCM_INTERNAL SCM scm_apply_subr (union scm_vm_stack_element *sp,