From: Tom Tromey <tromey@adacore.com>
Date: Mon, 6 Dec 2021 19:20:28 +0000 (-0700)
Subject: Avoid extra work in global_symbol_searcher::expand_symtabs
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c5a9fcdfeea5e961b8f73417c213fa570c8affb6;p=binutils-gdb.git

Avoid extra work in global_symbol_searcher::expand_symtabs

I noticed that global_symbol_searcher::expand_symtabs always passes a
file matcher to expand_symtabs_matching.  However, if 'filenames' is
empty, then this always returns true.  It's slightly more efficient to
pass a null file matcher in this case, because that lets the "quick"
symbol implementations skip any filename checks.

Regression tested on x86-64 Fedora 34.
---

diff --git a/gdb/symtab.c b/gdb/symtab.c
index 3f2eb64a7c4..68b6267f878 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -4678,11 +4678,16 @@ global_symbol_searcher::expand_symtabs
   enum search_domain kind = m_kind;
   bool found_msymbol = false;
 
+  auto do_file_match = [&] (const char *filename, bool basenames)
+    {
+      return file_matches (filename, filenames, basenames);
+    };
+  gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher = nullptr;
+  if (!filenames.empty ())
+    file_matcher = do_file_match;
+
   objfile->expand_symtabs_matching
-    ([&] (const char *filename, bool basenames)
-     {
-       return file_matches (filename, filenames, basenames);
-     },
+    (file_matcher,
      &lookup_name_info::match_any (),
      [&] (const char *symname)
      {