Fix crash with -D_GLIBCXX_DEBUG

I noticed a buildbot failure where gdb crashed in info-os.exp, when
compiled with -D_GLIBCXX_DEBUG:

    (gdb) info os procgroups
    /usr/include/c++/7/bits/stl_algo.h:4834:
    Error: comparison doesn't meet irreflexive requirements, assert(!(a < a)).
    Objects involved in the operation:
	iterator::value_type "< operator type" {
	  type = pid_pgid_entry;
	}

The bug here is that pid_pgid_entry::operator< violates the C++
irreflexivity rule; that is, that an object cannot be less than
itself.

Tested locally by re-running info-os.exp.

gdb/ChangeLog
2018-07-30  Tom Tromey  <tom@tromey.com>

	* nat/linux-osdata.c (pid_pgid_entry::operator<): Fix
	irreflexivity violation.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2cd7d6498b0aa60ef583e9a8a93e24eb492e345a..24ffeecda11b37028a9bea0d98b800d3d0150b90 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2018-07-30  Tom Tromey  <tom@tromey.com>
+
+       * nat/linux-osdata.c (pid_pgid_entry::operator<): Fix
+       irreflexivity violation.
+
 2018-07-30  Tom Tromey  <tom@tromey.com>
 
        * cli/cli-decode.c (lookup_cmd): Remove lint code.

diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index 25e895df1902c1ce359b7952b2ff5eeb108e7071..2323dcc878b26b21bfba73c5a8d652fc026f0ac0 100644 (file)
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -415,9 +415,11 @@ struct pid_pgid_entry
 
     /* Process group leaders always come first...  */
     if (this->is_leader ())
-      return true;
-
-    if (other.is_leader ())
+      {
+       if (!other.is_leader ())
+         return true;
+      }
+    else if (other.is_leader ())
       return false;
 
     /* ...else sort by PID.  */