[PATCH 2/4] ld: Refactor input_statement_is_archive_path() to not touch its argument

[Alan Modra]

On Fri, Apr 24, 2026 at 07:19:45PM -0700, Calvin Owens wrote:
> +	  char *tmp = stat_strdup (file_spec);
> +
> +	  tmp[sep - file_spec] = 0;
> +	  match = name_match (tmp, aname) == 0;
> +	  stat_free (tmp);

Let's not make an unnecessary copy.  I'm going to apply the following.
----

Assign strchr return to a const char* to match its arg in a couple of
places.  archive_path now returns a const char*, and
input_statement_is_archive_path now has a const char* sep arg.  If
you follow where these args come from in ldgram.y it can be seen that
they are in fact in writable memory, so it isn't necessary to copy
file_spec to poke in a zero which is restored before the function
returns.

Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Alan Modra <amodra@gmail.com>

diff --git a/ld/ldlang.c b/ld/ldlang.c
index dec3d586671..48dd33a49bb 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -337,10 +337,10 @@ stat_ldirname (const char *name)
 /* If PATTERN is of the form archive:file, return a pointer to the
    separator.  If not, return NULL.  */
 
-static char *
+static const char *
 archive_path (const char *pattern)
 {
-  char *p = NULL;
+  const char *p = NULL;
 
   if (link_info.path_separator == 0)
     return p;
@@ -362,7 +362,7 @@ archive_path (const char *pattern)
    return whether F matches FILE_SPEC.  */
 
 static bool
-input_statement_is_archive_path (const char *file_spec, char *sep,
+input_statement_is_archive_path (const char *file_spec, const char *sep,
 				 lang_input_statement_type *f)
 {
   bool match = false;
@@ -377,9 +377,10 @@ input_statement_is_archive_path (const char *file_spec, char *sep,
       if (sep != file_spec)
 	{
 	  const char *aname = bfd_get_filename (f->the_bfd->my_archive);
-	  *sep = 0;
+	  /* SEP which points into FILE_SPEC is in writable memory.  */
+	  *(char *) sep = 0;
 	  match = name_match (file_spec, aname) == 0;
-	  *sep = link_info.path_separator;
+	  *(char *) sep = link_info.path_separator;
 	}
     }
   return match;
@@ -421,7 +422,7 @@ walk_wild_file_in_exclude_list (struct name_list *exclude_list,
        list_tmp;
        list_tmp = list_tmp->next)
     {
-      char *p = archive_path (list_tmp->name);
+      const char *p = archive_path (list_tmp->name);
 
       if (p != NULL)
 	{
@@ -477,7 +478,7 @@ walk_wild_section_match (lang_wild_statement_type *ptr,
 {
   struct wildcard_list *sec;
   const char *file_spec = ptr->filename;
-  char *p;
+  const char *p;
 
   /* Check if filenames match.  */
   if (file_spec == NULL)
@@ -10946,7 +10947,7 @@ cmdline_fopen_temp (const char *path, const char *target,
 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
   {
     /* We could have foo/bar\\baz, or foo\\bar, or d:bar.  */
-    char *bslash = strrchr (path, '\\');
+    const char *bslash = strrchr (path, '\\');
 
     if (slash == NULL || (bslash != NULL && bslash > slash))
       slash = bslash;

-- 
Alan Modra