gdb/gdb-testsuite-fix-timeouts-in-gdb.threads-step-over-.patch

From cc96eb70e17260381e6c59c8de671468b59eee7f Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Thu, 16 Jan 2025 09:39:55 +0100
Subject: [PATCH] [gdb/testsuite] Fix timeouts in
 gdb.threads/step-over-thread-exit.exp

Once in a while, I run into a timeout in test-case
gdb.threads/step-over-thread-exit.exp:
...
(gdb) continue^M
Continuing.^M
[New Thread 0xfffff7cff1a0 (LWP 2874854)]^M
^M
Thread 97 "step-over-threa" hit Breakpoint 2, 0x0000000000410314 in \
  my_exit_syscall () at gdb/testsuite/lib/my-syscalls.S:74^M
74      SYSCALL (my_exit, __NR_exit)^M
(gdb) [Thread 0xfffff7cff1a0 (LWP 2874853) exited]^M
FAIL: $exp: step_over_mode=displaced: non-stop=on: target-non-stop=on: \
  schedlock=off: cmd=continue: ns_stop_all=0: iter 95: continue (timeout)
...

I can reproduce it more frequently by running with taskset -c <slow core id>.

Fix this by using -no-prompt-anchor.

This requires us to add -no-prompt-anchor to proc gdb_test_multiple.

Tested on aarch64-linux.

PR testsuite/32489
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32489
---
 gdb/testsuite/gdb.threads/step-over-thread-exit.exp | 5 +++--
 gdb/testsuite/lib/gdb.exp                           | 9 ++++++++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/gdb/testsuite/gdb.threads/step-over-thread-exit.exp b/gdb/testsuite/gdb.threads/step-over-thread-exit.exp
index 8eb93995657..98cc94e9528 100644
--- a/gdb/testsuite/gdb.threads/step-over-thread-exit.exp
+++ b/gdb/testsuite/gdb.threads/step-over-thread-exit.exp
@@ -193,7 +193,7 @@ proc test {step_over_mode non-stop target-non-stop schedlock cmd ns_stop_all} {
 		with_test_prefix "iter $i" {
 		    set ok 0
 		    set thread "<unknown>"
-		    gdb_test_multiple "continue" "" {
+		    gdb_test_multiple "continue" "" -no-prompt-anchor {
 			-re -wrap "Thread ($::decimal) .*hit Breakpoint $::decimal.* my_exit_syscall .*" {
 			    set thread $expect_out(1,string)
 			    set ok 1
@@ -206,7 +206,8 @@ proc test {step_over_mode non-stop target-non-stop schedlock cmd ns_stop_all} {
 		    }
 
 		    if {${non-stop}} {
-			gdb_test -nopass "thread $thread" "Switching to thread .*" \
+			gdb_test -nopass -no-prompt-anchor "thread $thread" \
+			    "Switching to thread .*" \
 			    "switch to event thread"
 		    }
 		}
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 577eb9368cf..b103c117258 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1024,6 +1024,10 @@ proc command_to_message { command } {
 #   if one of them matches.  If MESSAGE is empty COMMAND will be used.
 # -prompt PROMPT_REGEXP specifies a regexp matching the expected prompt
 #   after the command output.  If empty, defaults to "$gdb_prompt $".
+# -no-prompt-anchor specifies that if the default prompt regexp is used, it
+#   should not be anchored at the end of the buffer.  This means that the
+#   pattern can match even if there is stuff output after the prompt.  Does not
+#   have any effect if -prompt is specified.
 # -lbl specifies that line-by-line matching will be used.
 # EXPECT_ARGUMENTS will be fed to expect in addition to the standard
 #   patterns.  Pattern elements will be evaluated in the caller's
@@ -1123,6 +1127,7 @@ proc gdb_test_multiple { command message args } {
 
     set line_by_line 0
     set prompt_regexp ""
+    set prompt_anchor 1
     for {set i 0} {$i < [llength $args]} {incr i} {
 	set arg [lindex $args $i]
 	if { $arg  == "-prompt" } {
@@ -1130,6 +1135,8 @@ proc gdb_test_multiple { command message args } {
 	    set prompt_regexp [lindex $args $i]
 	} elseif { $arg == "-lbl" } {
 	    set line_by_line 1
+	} elseif { $arg == "-no-prompt-anchor" } {
+	    set prompt_anchor 0
 	} else {
 	    set user_code $arg
 	    break
@@ -1141,7 +1148,7 @@ proc gdb_test_multiple { command message args } {
 	error "Too few arguments to gdb_test_multiple"
     }
 
-    set prompt_regexp [fill_in_default_prompt $prompt_regexp true]
+    set prompt_regexp [fill_in_default_prompt $prompt_regexp $prompt_anchor]
 
     if { $message == "" } {
 	set message [command_to_message $command]

base-commit: cd4f4a663f82e2f8bee58f3ef000964a2dd82769
-- 
2.43.0