[glibc] Clarify purpose of assert in _dl_lookup_symbol_x

[glibc] Clarify purpose of assert in _dl_lookup_symbol_x

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ca136bb0a36d0a7056c926bfe5126873566efe40

commit ca136bb0a36d0a7056c926bfe5126873566efe40
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Oct 31 13:28:26 2019 +0100

    Clarify purpose of assert in _dl_lookup_symbol_x
    
    Only one of the currently defined flags is incompatible with versioned
    symbol lookups, so it makes sense to check for that flag and not its
    complement.
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>
    Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
    Change-Id: I3384349cef90cfd91862ebc34a4053f0c0a99404

Diff:
---
 elf/dl-lookup.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index fd44cd4..aaaf437 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -792,11 +792,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
 
   bump_num_relocations ();
 
-  /* No other flag than DL_LOOKUP_ADD_DEPENDENCY or DL_LOOKUP_GSCOPE_LOCK
-     is allowed if we look up a versioned symbol.  */
-  assert (version == NULL
-	  || (flags & ~(DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_GSCOPE_LOCK))
-	     == 0);
+  /* DL_LOOKUP_RETURN_NEWEST does not make sense for versioned
+     lookups.  */
+  assert (version == NULL || !(flags & DL_LOOKUP_RETURN_NEWEST));
 
   size_t i = 0;
   if (__glibc_unlikely (skip_map != NULL))