gdb/symtab: check name matches before expanding a CU

The added check fixes the case when an unqualified lookup
name without template arguments causes expansion of many CUs
which contain the name with template arguments.

This is similar to what dw2_expand_symtabs_matching_symbol does
before expanding the CU.

In the referenced issue the lookup name was wxObjectDataPtr and many
CUs had names like wxObjectDataPtr<wxBitmapBundleImpl>. This caused
their expansion and the lookup took around a minute. The added check
helps to avoid the expansion and makes the symbol lookup to return in
a second or so.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30520

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 049ee4d52ff203198da29fb0029da8c681d8b248..e2f010b7849bdb451e0ede3f7818d960a044d6e8 100644 (file)
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -16694,9 +16694,25 @@ cooked_index_functions::expand_symtabs_matching
                = lookup_name_without_params.match_type ();
              if ((match_type == symbol_name_match_type::FULL
                   || (lang != language_ada
-                      && match_type == symbol_name_match_type::EXPRESSION))
-                 && parent != nullptr)
-               continue;
+                      && match_type == symbol_name_match_type::EXPRESSION)))
+               {
+                 if (parent != nullptr)
+                   continue;
+
+                 if (entry->lang != language_unknown)
+                   {
+                     const language_defn *lang_def = language_def (entry->lang);
+                     lookup_name_info last_segment_lookup_name (
+                       last_name.data (), symbol_name_match_type::FULL,
+                       false, true);
+                     symbol_name_matcher_ftype *name_matcher
+                       = lang_def->get_symbol_name_matcher
+                         (last_segment_lookup_name);
+                     if (!name_matcher (entry->canonical,
+                                        last_segment_lookup_name, nullptr))
+                       continue;
+                   }
+             }
            }
          else
            {