DLL linking performance

[Pascal Obry <pascal at obry dot net>]

Hi There!

Following the previous discussion with Kai about the DLL load time
performance I have switched the linker to use the runtime pseudo reloc
v1 circuitry.

This indeed has made a big difference in loading the DLL, it is now
almost instantaneous where it was more than 2 minutes before.

But now the DLL *link* time has regressed at lot. My initial test shows
that creating the DLL is 5 times slower.

I've been analyzing this issue. Here are my findings:

- There is two sorts routines un ldlang.c

  wild_sort and wild_sort_fast

  As the later imply it is fast and the former is slow.

- Those sort routines get called from

  output_section_callback and output_section_callback_fast respectively.

- Those routines are called from wild:

   static void
   wild (lang_wild_statement_type *s,
         const char *target ATTRIBUTE_UNUSED,
         lang_output_section_statement_type *output)
   {
     struct wildcard_list *sec;

     if (s->handler_data[0]
         && s->handler_data[0]->spec.sorted == by_name
         && !s->filenames_sorted)
       {
         lang_section_bst_type *tree;

         walk_wild (s, output_section_callback_fast, output);

         tree = s->tree;
         if (tree)
           {
             output_section_callback_tree_to_list (s, tree, output);
             s->tree = NULL;
           }
       }
     else
       walk_wild (s, output_section_callback, output);


The fast routine is called when the data are sorted. Do you think this
can be improved?  Where is this sort should be done?

My initial investigation seems to indicate that this sorting status is
done on the linker script (SORT_BY_NAME), but I'm lost in the code...

Any guidance will be much appreciated.

Thanks.

Pascal.

-- 

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--| Pascal Obry                           Team-Ada Member
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