diff --git a/asm/nasm.c b/asm/nasm.c
index e9cb5c83..8b8982f2 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -454,6 +454,7 @@ static char *nasm_quote_filename(const char *fn)
 {
     const unsigned char *p =
         (const unsigned char *)fn;
+    size_t len;
 
     if (!p || !*p)
         return nasm_strdup("\"\"");
@@ -477,7 +478,8 @@ static char *nasm_quote_filename(const char *fn)
     return nasm_strdup(fn);
 
 quote:
-    return nasm_quote(fn, NULL);
+    len = strlen(fn);
+    return nasm_quote(fn, &len);
 }
 
 static void timestamp(void)
diff --git a/asm/preproc.c b/asm/preproc.c
index fc1b0df1..8fb9dfbb 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -797,10 +797,11 @@ Token *quote_token(Token *t)
  */
 static Token *quote_any_token(Token *t)
 {
-    size_t len;
+    const char *s = tok_text(t);
+    size_t len = strlen(s);
     char *p;
 
-    p = nasm_quote(tok_text(t), &len);
+    p = nasm_quote(s, &len);
     t->type = TOK_STRING;
     return set_text_free(t, p, len);
 }