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# Copyright (C) 2015 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This test exercises the case of stopping for a breakpoint hit of one
# thread, then switching to a thread that has a status pending and
# continuing.
standard_testfile
if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] {
return -1
}
if ![runto_main] {
untested "could not run to main"
return -1
}
set break_line [gdb_get_line_number "break here"]
# Return current thread's number.
proc get_current_thread {} {
global gdb_prompt
set thread ""
set msg "get thread number"
gdb_test_multiple "print /x \$_thread" $msg {
-re "\\$\[0-9\]* = (0x\[0-9a-zA-Z\]+).*$gdb_prompt $" {
set thread $expect_out(1,string)
pass "$msg"
}
}
return ${thread}
}
# There are two threads in the program that are running the same tight
# loop, where we place a breakpoint. Sometimes we'll get a breakpoint
# trigger for thread 2, with the breakpoint event of thread 3 pending,
# other times the opposite. The original bug that motivated this test
# depended on the event thread being the highest numbered thread. We
# try the same multiple times, which should cover both threads
# reporting the event.
set attempts 20
# These track whether we saw events for both threads 2 and 3. If the
# backend always returns the breakpoint hit for the same thread, then
# it fails to make sure threads aren't starved, and we'll fail the
# assert after the loop.
set saw_thread_2 0
set saw_thread_3 0
for {set i 0} {$i < $attempts} {incr i} {
with_test_prefix "attempt $i" {
gdb_test "b $srcfile:$break_line" \
"Breakpoint .* at .*$srcfile, line $break_line.*" \
"set break in tight loop"
gdb_test "continue" \
"$srcfile:$break_line.*" \
"continue to tight loop"
# Switch to the thread that did _not_ report the event (and
# thus may have a pending status). At the time this test was
# written this was necessary to make linux-nat.c short-circuit
# the resume and go straight to consuming the pending event.
set thread [get_current_thread]
if {$thread == 2} {
incr saw_thread_2
set thread 3
} else {
incr saw_thread_3
set thread 2
}
gdb_test "thread $thread" \
"Switching to thread $thread .*" \
"switch to non-event thread"
# Delete all breakpoints so that continuing doesn't switch
# back to the event thread to do a step-over, which would mask
# away the original bug, which depended on the event thread
# still having TARGET_STOPPED_BY_SW_BREAKPOINT stop_reason.
delete_breakpoints
# In the original bug, continuing would trigger an internal
# error in the linux-nat.c backend.
set msg "continue for ctrl-c"
gdb_test_multiple "continue" $msg {
-re "Continuing" {
pass $msg
}
}
# Wait a bit for GDB to give the terminal to the inferior,
# otherwise ctrl-c too soon can result in a "Quit".
sleep 1
send_gdb "\003"
set msg "caught interrupt"
gdb_test_multiple "" $msg {
-re "Program received signal SIGINT.*$gdb_prompt $" {
pass $msg
}
}
}
}
verbose -log "saw_thread_2=$saw_thread_2"
verbose -log "saw_thread_3=$saw_thread_3"
gdb_assert {$saw_thread_2 > 0 && $saw_thread_3 > 0} "no thread starvation"
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