diff --git a/output/codeview.c b/output/codeview.c
index f9750bfc..571cbabe 100644
--- a/output/codeview.c
+++ b/output/codeview.c
@@ -44,6 +44,7 @@
 
 #include "nasm.h"
 #include "nasmlib.h"
+#include "preproc.h"
 #include "saa.h"
 #include "output/outlib.h"
 #include "output/pecoff.h"
@@ -308,7 +309,7 @@ static void calc_md5(const char *const filename,
     FILE *f;
     MD5_CTX ctx;
 
-    f = fopen(filename, "r");
+    f = pp_input_fopen(filename);
     if (!f)
         goto done;
 
diff --git a/preproc.c b/preproc.c
index e33a6d7d..78263fb3 100644
--- a/preproc.c
+++ b/preproc.c
@@ -1559,6 +1559,23 @@ static FILE *inc_fopen(const char *file, StrList **dhead, StrList ***dtail,
     return NULL;
 }
 
+/*
+ * Opens an include or input file. Public version, for use by modules
+ * that get a file:lineno pair and need to look at the file again
+ * (e.g. the CodeView debug backend). Returns NULL on failure.
+ */
+FILE *pp_input_fopen(const char *filename)
+{
+    FILE *fp;
+    StrList *xsl = NULL;
+    StrList **xst = &xsl;
+
+    fp = inc_fopen(filename, &xsl, &xst, true);
+    if (xsl)
+        nasm_free(xsl);
+    return fp;
+}
+
 /*
  * Determine if we should warn on defining a single-line macro of
  * name `name', with `nparam' parameters. If nparam is 0 or -1, will
diff --git a/preproc.h b/preproc.h
index fdda37ce..3dee45f2 100644
--- a/preproc.h
+++ b/preproc.h
@@ -48,4 +48,7 @@ typedef const unsigned char macros_t;
 
 enum preproc_token pp_token_hash(const char *token);
 
+/* Opens an include file or input file. This uses the include path. */
+FILE *pp_input_fopen(const char *filename);
+
 #endif