Commit: objcopy: Fail if attempting to redefine symbols in LTO files

Commit: objcopy: Fail if attempting to redefine symbols in LTO files

[Nick Clifton]

Hi Guys,

  I am applying the patch below to add a fatal error message to objcopy
  if the user attempts to use --redefine-sym (or --redefine-syms) on an
  object file containing LTO information.  Since LTO uses its own symbol
  tables, plus modifying symbols in the ordinary symbol table, symbol
  redefinition is not going to work.  (Plus I did not fancy trying to
  implement the code to make it work.  Especially since the LTO symbol
  table format is not fixed or even well defined).

Cheers
  Nick

binutils/ChangeLog
2021-09-30  Nick Clifton  <nickc@redhat.com>

	* objcopy.c (filter_symbols): Fail if attempting to dredefine
	symbols in an LTO object file.

diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index fd7557fe433..75fd89d338b 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -1542,6 +1542,13 @@ filter_symbols (bfd *abfd, bfd *obfd, asymbol **osyms,
 	{
 	  char *new_name;
 
+	  if (name[0] == '_'
+	      && name[1] == '_'
+	      && strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0)
+	    {
+	      fatal (_("redefining symbols does not work on LTO-compiled object files"));
+	    }
+	  
 	  new_name = (char *) lookup_sym_redefinition (name);
 	  if (new_name == name
 	      && (flags & BSF_SECTION_SYM) != 0)