Add quick_symbol_functions::compute_main_name

This adds a new compute_main_name method to quick_symbol_functions.
Currently there are no implementations of this, but a subsequent patch
will add one.

gdb/objfiles.h

@@ -605,6 +605,9 @@ public:
   void map_symbol_filenames (gdb::function_view<symbol_filename_ftype> fun,
 			     bool need_fullname);
 
+  /* See quick_symbol_functions.  */
+  void compute_main_name ();
+
   /* See quick_symbol_functions.  */
   struct compunit_symtab *find_compunit_symtab_by_address (CORE_ADDR address);
 

gdb/quick-symbol.h

@@ -185,6 +185,15 @@ struct quick_symbol_functions
 	gdb::function_view<symbol_filename_ftype> fun,
 	bool need_fullname) = 0;
 
+  /* Compute the name and language of the main function for the given
+     objfile.  Normally this is done during symbol reading, but this
+     method exists in case this work is done in a worker thread and
+     must be waited for.  The implementation can call
+     set_objfile_main_name if results are found.  */
+  virtual void compute_main_name (struct objfile *objfile)
+  {
+  }
+
   /* Return true if this class can lazily read the symbols.  This may
      only return true if there are in fact symbols to be read, because
      this is used in the implementation of 'has_partial_symbols'.  */

gdb/symfile-debug.c

@@ -467,6 +467,18 @@ objfile::map_symbol_filenames (gdb::function_view<symbol_filename_ftype> fun,
     iter->map_symbol_filenames (this, fun, need_fullname);
 }
 
+void
+objfile::compute_main_name ()
+{
+  if (debug_symfile)
+    gdb_printf (gdb_stdlog,
+		"qf->compute_main_name (%s)\n",
+		objfile_debug_name (this));
+
+  for (const auto &iter : qf_require_partial_symbols ())
+    iter->compute_main_name (this);
+}
+
 struct compunit_symtab *
 objfile::find_compunit_symtab_by_address (CORE_ADDR address)
 {

gdb/symtab.c

@@ -6334,6 +6334,8 @@ find_main_name (void)
      accurate.  */
   for (objfile *objfile : current_program_space->objfiles ())
     {
+      objfile->compute_main_name ();
+
       if (objfile->per_bfd->name_of_main != NULL)
 	{
 	  set_main_name (pspace,