[gdb/testsuite] Yet another attempt to fix gdb.threads/thread-specific-bp.exp

When running test-case gdb.threads/thread-specific-bp.exp using taskset to
select an Efficient-core in a loop, it fails 19 out of 100 runs.

For example, like this:
...
(gdb) continue -a^M
Continuing.^M
^M
Thread 1 "thread-specific" hit Breakpoint 4, end () at thread-specific-bp.c:29^M
29      }^M
(gdb) FAIL: $exp: non_stop=on: continue to end
[Thread 0x7ffff7cbe6c0 (LWP 2348848) exited]^M
Thread-specific breakpoint 3 deleted - thread 2 no longer in the thread list.^M
...

The way we're trying to match this gdb output is:
...
    gdb_test_multiple "$cmd" "continue to end" {
	-re "$\r\n${gdb_prompt} .*${msg_re}\r\n" {
	    pass $gdb_test_name
	}
	-re "\r\n${msg_re}\r\n.*$gdb_prompt " {
	    pass $gdb_test_name
 	}
     }
...

The problem is that the two -re clauses above do not match the output ending
in a prompt, so the default fail in gdb_test_multiple triggers.

Fix this by splitting this up in two gdb_test_multiple calls:
- the first matches a prompt (with or without preceding $msg_re), making sure
  that the default fail doesn't trigger, and
- the second matches $msg_re, if that was not already matched by the first call.

Using this approach, the test-case passes 100 out of 100 runs.

Tested on x86_64-linux, also with make-check-all.sh.

PR testsuite/32688
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32688

diff --git a/gdb/testsuite/gdb.threads/thread-specific-bp.exp b/gdb/testsuite/gdb.threads/thread-specific-bp.exp
index 8f48b61eb6ca214a29f9519a99c2f53c0519e97b..e4f83620d278f85a54163174be9f54fb513b8d56 100644 (file)
--- a/gdb/testsuite/gdb.threads/thread-specific-bp.exp
+++ b/gdb/testsuite/gdb.threads/thread-specific-bp.exp
@@ -95,12 +95,21 @@ proc check_thread_specific_breakpoint {non_stop} {
                  "-" \
                  "thread 2 no longer in the thread list\\."]]
 
-    gdb_test_multiple "$cmd" "continue to end" {
-       -re "$\r\n${gdb_prompt} .*${msg_re}\r\n" {
+    set test "continue to end"
+    set try_again 0
+    gdb_test_multiple $cmd $test -no-prompt-anchor {
+       -re -wrap "\r\n${msg_re}(?=\r\n).*" {
            pass $gdb_test_name
        }
-       -re "\r\n${msg_re}\r\n.*$gdb_prompt " {
-           pass $gdb_test_name
+       -re -wrap "" {
+           set try_again 1
+       }
+    }
+    if { $try_again } {
+       gdb_test_multiple "" $test {
+           -re "\r\n${msg_re}(?=\r\n)" {
+               pass $gdb_test_name
+           }
        }
     }