Re: [PATCH] [gdb/symtab] Find main language without symtab expansion

[Tom Tromey <tom@tromey.com>]

>>>>> "Tom" == Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> writes:

Tom> Reimplement the feature by adding
Tom> cooked_index_functions::lookup_global_symbol_language.

Thanks for the patch.

Tom> +    /* Expansion of large CUs can be slow.  By returning the language of main
Tom> +       here for C and C++, we avoid CU expansion during set_initial_language.
Tom> +       But by doing a symbol lookup in the cooked index, we are forced to wait
Tom> +       for finalization to complete.  See PR symtab/30174 for ideas how to
Tom> +       bypass that as well.  */
Tom> +    cooked_index *table = per_bfd->index_table->index_for_writing ();

I think it's more normal to use:

  cooked_index *table
    = (gdb::checked_static_cast<cooked_index *>
       (per_bfd->index_table.get ()));

in the body of cooked_index_functions.

Tom> +    for (const cooked_index_entry *entry : table->find (name, false))

I think this is probably racy, if the intent is not to wait for
finalization, because cooked_index_shard::find uses the canonical name.

Maybe we need to resurrect the approach of looking for "main" in C/C++
CUs.  I don't really remember all the state of this right now, there's
been a lot of flux.  I did also reimplement some of this on my
background DWARF reading branch, but I think that's kind of invasive.

Tom