Re: Sporadic failures of selftest tests

[Pedro Alves <palves@redhat.com>]

On 10/17/2017 04:54 PM, Pedro Alves wrote:

> Commit bf4692711232 ("Eliminate catch_errors") also did this:
> 
>  @@ -1145,7 +1142,15 @@ captured_main (void *data)
>        change - SET_TOP_LEVEL() - has been eliminated.  */
>     while (1)
>       {
>  -      catch_errors (captured_command_loop, 0, "", RETURN_MASK_ALL);
>  +      TRY
>  +       {
>  +         captured_command_loop ();
>  +       }
>  +      CATCH (ex, RETURN_MASK_ALL)
>  +       {
>  +         exception_print (gdb_stderr, ex);
>  +       }
>  +      END_CATCH
>       }
>  
> So most probably before that commit captured_command_loop
> wasn't inlined in captured main (unless LTO, maybe).

Probably the best fix would be to move away from selftest
entirely and convert them to unit tests instead.

Meanwhile, how about this as an easy fix?  We could try
playing games with making functions extern, but maybe
that'd break again with LTO.

Seems to work for gdb.gdb/selftest.exp and gdb.gdb/complaints.exp
at least.

(I think we can use __attribute__ directly because
include/ansidecl.h defines it to empty on non-gcc or
older gccs.)

From: Pedro Alves <palves@redhat.com>
Date: 2017-10-17 15:04:11 +0100

prevent inlining captured_command_loop
---

 gdb/main.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gdb/main.c b/gdb/main.c
index beb8203..a60cd50 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -307,6 +307,11 @@ setup_alternate_signal_stack (void)
 
 /* Call command_loop.  */
 
+/* Prevent inlining this function for the benefit of gdb's selftests
+   in the testsuite.  Those tests want to run GDB under GDB and stop
+   here.  */
+static void captured_command_loop () __attribute__((noinline));
+
 static void
 captured_command_loop ()
 {