section-select: Fix performance problem (PR30367)

when using many wild-statements with non-wildcard filenames we
were running into quadraticness via repeatedly using lookup_name
on a long list of loaded files.  I've originally retained using
lookup_name because that preserved existing behaviour most obviously.
In particular in matching wild-statements when using a non-wildcard
filename it matches against local_sym_name, not the filename member.
If the wildspec would have an archive-spec or a wildcard it would use
the filename member, though.  Also it would load the named file
(and ignore it, as being not equal to the currently considered
input-statement).

Rewrite this to not use lookup_name but retain the comparison
against local_sym_name with a comment to that effect.

	PR 30367
	* ldlang.c (walk_wild_section_match): Don't use lookup_name
	but directly compare spec and local_sym_name.

(cherry picked from commit 8f5cd47bee6c07c33aeda758d8d8db5f81ae03e7)

1 files changed, 12 insertions, 4 deletions

diff --git a/ld/ldlang.c b/ld/ldlang.c
index 6aaf8e99bfa..9b92e4a801a 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -431,10 +431,18 @@ walk_wild_section_match (lang_wild_statement_type *ptr,
     }
   else
     {
-      lang_input_statement_type *f;
-      /* Perform the iteration over a single file.  */
-      f = lookup_name (file_spec);
-      if (f != file)
+      /* XXX Matching against non-wildcard filename in wild statements
+	 was done by going through lookup_name, which uses
+	 ->local_sym_name to compare against, not ->filename.  We retain
+	 this behaviour even though the above code paths use filename.
+	 It would be more logical to use it here as well, in which
+	 case the above wildcard() arm could be folded into this by using
+	 name_match.  This would also solve the worry of what to do
+	 about unset local_sym_name (in which case lookup_name simply adds
+	 the input file again).  */
+      const char *filename = file->local_sym_name;
+      if (filename == NULL
+	  || filename_cmp (filename, file_spec) != 0)
 	return;
     }