gcc/lto/lto-symtab.h

/* LTO symbol table merging.
   Copyright (C) 2009-2021 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

extern void lto_symtab_merge_decls (void);
extern void lto_symtab_merge_symbols (void);
extern tree lto_symtab_prevailing_decl (tree decl);
extern tree lto_symtab_prevailing_virtual_decl (tree decl);

/* Mark DECL to be previailed by PREVAILING.
   Use DECL_LANG_FLAG_0 and DECL_CHAIN as special markers; those do not
   disturb debug_tree and diagnostics.
   We are safe to modify them as we wish, because the declarations disappear
   from the IL after the merging.  */

inline void
lto_symtab_prevail_decl (tree prevailing, tree decl)
{
  gcc_checking_assert (! DECL_LANG_FLAG_0 (decl));
  gcc_assert (TREE_PUBLIC (decl) || DECL_EXTERNAL (decl));
  DECL_CHAIN (decl) = prevailing;
  DECL_LANG_FLAG_0 (decl) = 1;
}

/* Given the decl DECL, return the prevailing decl with the same name. */

inline tree
lto_symtab_prevailing_decl (tree decl)
{
  if (DECL_LANG_FLAG_0 (decl))
    return DECL_CHAIN (decl);
  else
    {
      if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == FUNCTION_DECL)
	  && DECL_VIRTUAL_P (decl)
	  && (TREE_PUBLIC (decl) || DECL_EXTERNAL (decl))
	  && !symtab_node::get (decl))
	return lto_symtab_prevailing_virtual_decl (decl);
      return decl;
    }
}