gdb: Ensure that !(a < a) is true in sort_cmp on obj_section objects

[deliverable/binutils-gdb.git] / gdb / objfiles.c

diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index fd1cbf764d67029b98fa6510fcee4b861c9ce2a4..b5bc09f41eafc7f335567d6d8cfc4348dc0af82e 100644 (file)
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -1044,19 +1044,23 @@ sort_cmp (const struct obj_section *sect1, const obj_section *sect2)
         doesn't happen at all).  If you discover that significant time is
         spent in the loops below, do 'set complaints 100' and examine the
         resulting complaints.  */
-
       if (objfile1 == objfile2)
        {
-         /* Both sections came from the same objfile.  We are really confused.
-            Sort on sequence order of sections within the objfile.  */
+         /* Both sections came from the same objfile.  We are really
+            confused.  Sort on sequence order of sections within the
+            objfile.  The order of checks is important here, if we find a
+            match on SECT2 first then either SECT2 is before SECT1, or,
+            SECT2 == SECT1, in both cases we should return false.  The
+            second case shouldn't occur during normal use, but std::sort
+            does check that '!(a < a)' when compiled in debug mode.  */
 
          const struct obj_section *osect;
 
          ALL_OBJFILE_OSECTIONS (objfile1, osect)
-           if (osect == sect1)
-             return true;
-           else if (osect == sect2)
+           if (osect == sect2)
              return false;
+           else if (osect == sect1)
+             return true;
 
          /* We should have found one of the sections before getting here.  */
          gdb_assert_not_reached ("section not found");