Prevent the --keep-global-symbol and --globalize-symbol options from being used together.

This is the result of an email thread starting here:
  https://sourceware.org/ml/binutils/2018-09/msg00031.html

The main point of the thread is this observation:

  * Supposing we had an object file with two globals, SomeGlobal and
  SomeOtherGlobal, if one were to do "--globalize-symbol SomeGlobal
  --keep-global-symbol SomeOtherGlobal", you might expect that both
  SomeGlobal and SomeOtherGlobal are global in the output file... but it
  isn't. Because --keep-global-symbol is set and doesn't include
  SomeGlobal, SomeGlobal will be demoted to a local symbol. And because
  the check to see if we should apply the --globalize-symbol flag checks
  "flags" (the original flag set), and not "sym->flags", it decides not
  to do anything, so SomeGlobal remains a local symbol. Although this is
  a weird edge case, should this be changed so that --keep-global-symbol
  implicitly keeps anything also specified via --globalize-symbol? (The
  code seems technically correct with respect to the documentation, but
  IMO the behavior is counter-intuitive).

binutils* objcopy.c (copy_main): Issue a fata error if the
	--keep-global-symbol(s) and the --globalize-symbol(s) options are
	used together.
	* doc/binutils.texi: Document that the two options are
	incompatible.
	* testsuite/binutils-all/copy-5.d: New test.
	* testsuite/binutils-all/objcopy.exp: Run the new test.

1 files changed, 9 insertions, 0 deletions

diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 9af3c1e..d8ae1f9 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -4753,6 +4753,8 @@ copy_main (int argc, char *argv[])
   bfd_boolean show_version = FALSE;
   bfd_boolean change_warn = TRUE;
   bfd_boolean formats_info = FALSE;
+  bfd_boolean use_globalize = FALSE;
+  bfd_boolean use_keep_global = FALSE;
   int c;
   struct stat statbuf;
   const bfd_arch_info_type *input_arch = NULL;
@@ -4871,10 +4873,12 @@ copy_main (int argc, char *argv[])
 	  break;
 
 	case OPTION_GLOBALIZE_SYMBOL:
+	  use_globalize = TRUE;
 	  add_specific_symbol (optarg, globalize_specific_htab);
 	  break;
 
 	case 'G':
+	  use_keep_global = TRUE;
 	  add_specific_symbol (optarg, keepglobal_specific_htab);
 	  break;
 
@@ -5306,11 +5310,13 @@ copy_main (int argc, char *argv[])
 	  break;
 
 	case OPTION_GLOBALIZE_SYMBOLS:
+	  use_globalize = TRUE;
 	  add_specific_symbols (optarg, globalize_specific_htab,
 				&globalize_specific_buffer);
 	  break;
 
 	case OPTION_KEEPGLOBAL_SYMBOLS:
+	  use_keep_global = TRUE;
 	  add_specific_symbols (optarg, keepglobal_specific_htab,
 				&keepglobal_specific_buffer);
 	  break;
@@ -5446,6 +5452,9 @@ copy_main (int argc, char *argv[])
 	}
     }
 
+  if (use_globalize && use_keep_global)
+    fatal(_("--globalize-symbol(s) is incompatible with -G/--keep-global-symbol(s)"));
+
   if (formats_info)
     {
       display_info ();