binutils-gdb/gdb/testsuite/gdb.threads/step-over-thread-exit.exp

# Copyright 2021-2022 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/>.

# Test stepping over a breakpoint installed on an instruction that
# exits the thread.

standard_testfile .c

set syscalls_src $srcdir/lib/my-syscalls.S

if { [build_executable "failed to prepare" $testfile \
	  [list $srcfile $syscalls_src] {debug pthreads}] == -1 } {
    return
}

# Test stepping/continuing at an exit syscall instruction.
#
# Each argument is a different testing axis.
#
# STEP_OVER_MODE can be one of:
#
#   - none: don't put a breakpoint on the exit syscall instruction.
#
#   - inline: put a breakpoint on the exit syscall instruction, and
#     use in-line stepping to step over it (disable
#     displaced-stepping).
#
#   - displaced: same, but use displaced stepping.
#
# SCHEDLOCK can be "on" or "off".
#
# CMD is the GDB command to run when at the exit syscall instruction.
#
# NS_STOP_ALL is only used if testing "set non-stop on", and indicates
# whether to have GDB explicitly stop all threads before continuing to
# thread exit.
#
proc test {step_over_mode non-stop target-non-stop schedlock cmd ns_stop_all} {
    if {${non-stop} == "off" && $ns_stop_all} {
	error "invalid arguments"
    }

    save_vars ::GDBFLAGS {
	append ::GDBFLAGS " -ex \"maintenance set target-non-stop ${target-non-stop}\""
	append ::GDBFLAGS " -ex \"set non-stop ${non-stop}\""
	clean_restart $::binfile
    }

    if { $step_over_mode == "none" } {
	# Nothing to do.
    } elseif { $step_over_mode == "inline" } {
	gdb_test_no_output "set displaced-stepping off"
    } elseif { $step_over_mode == "displaced" } {
	gdb_test_no_output "set displaced-stepping on"
    } else {
	error "Invalid step_over_mode value: $step_over_mode"
    }

    if {$schedlock
	|| (${non-stop} == "on" && $ns_stop_all)} {

	gdb_test_no_output "set args 1"

	if { ![runto my_exit_syscall] } {
	    return
	}

	if {${non-stop} == "on"} {
	    # The test only spawns one thread at a time, so this just
	    # stops the main thread.  IOW, we only need to wait for
	    # one stop.
	    gdb_test_multiple "interrupt -a" "" {
		-re "$::gdb_prompt " {
		    gdb_test_multiple "" $gdb_test_name {
			-re "Thread 1 \[^\r\n\]*stopped." {
			    pass $gdb_test_name
			}
		    }
		}
	    }

	    gdb_test "thread 2" "Switching to thread 2 .*"
	}

	gdb_test_no_output "set scheduler-locking ${schedlock}"

	# If testing a step-over is requested, leave the breakpoint at
	# the current instruction to force a step-over; otherwise,
	# remove it.
	if { $step_over_mode == "none" } {
	    delete_breakpoints
	}

	if {$cmd == "continue"} {
	    gdb_test "continue" \
		"No unwaited-for children left." \
		"continue stops when thread exits"
	} else {
	    gdb_test_multiple $cmd "command aborts when thread exits" {
		-re "Command aborted, thread exited\\.\r\n$::gdb_prompt " {
		    pass $gdb_test_name
		}
	    }
	}
    } else {
	# Schedlock is off here.
	#
	# With "continue" and no scheduler-locking, GDB doesn't stop
	# with "Command aborted, thread exited." when the thread
	# exits, it just lets the inferior continue running freely.
	# So we test that we can move past the thread exit, and that
	# other threads can be freely scheduled.  We do that by
	# spawning another thread as soon as the first exit.  We test
	# that a number of times.  This should also exercise GDB's
	# handling of inline or displaced step-overs, that GDB handles
	# the related resource accounting correctly when the stepping
	# thread exits, etc.
	#
	# With "continue" and $step_over_mode == "none" however, after
	# the first my_exit_syscall breakpoint hit, we will remove the
	# breakpoint, so no other thread would ever hit it again.  So
	# might as well just test one thread.
	#
	# With step/next, GDB aborts the execution command with
	# "Command aborted, thread exited." when the stepping thread
	# exits.  If we let the main spawn another thread as soon as
	# the first exits, it would be possible for that new thread to
	# hit the exit syscall insn breakpoint quickly enough that it
	# would be reported to be user before the first thread exit
	# would be, which would confuse testing.  To avoid that, we
	# only spawn one thread, too.
	#
	if {$cmd != "continue" || $step_over_mode == "none"} {
	    set n_threads 1
	} else {
	    set n_threads 100
	}

	gdb_test_no_output "set args $n_threads"

	if { ![runto_main] } {
	    return
	}

	gdb_breakpoint "my_exit_syscall"

	gdb_test_no_output "set scheduler-locking ${schedlock}"

	if {$cmd != "continue" || $step_over_mode == "none"} {
	    set thread "<unknown>"
	    gdb_test_multiple "continue" "" {
		-re -wrap "Thread ($::decimal) .*hit Breakpoint $::decimal.* my_exit_syscall .*" {
		    set thread $expect_out(1,string)
		}
	    }
	    if {${non-stop}} {
		gdb_test -nopass "thread $thread" "Switching to thread .*" \
		    "switch to event thread"
	    }

	    # If testing a step-over is requested, leave the breakpoint at
	    # the current instruction to force a step-over; otherwise,
	    # remove it.
	    if { $step_over_mode == "none" } {
		delete_breakpoints
	    }

	    if {$cmd == "continue"} {
		gdb_continue_to_end "continue to end" "continue" 1
	    } else {
		gdb_test_multiple $cmd "command aborts when thread exits" {
		    -re "Command aborted, thread exited\\.\r\n$::gdb_prompt " {
			pass $gdb_test_name
		    }
		}
		gdb_test "p \$_thread == $thread" "= 1" \
		    "selected thread didn't change"
	    }
	} else {
	    for { set i 0 } { $i < 100 } { incr i } {
		with_test_prefix "iter $i" {
		    set ok 0
		    set thread "<unknown>"
		    gdb_test_multiple "continue" "" {
			-re -wrap "Thread ($::decimal) .*hit Breakpoint $::decimal.* my_exit_syscall .*" {
			    set thread $expect_out(1,string)
			    set ok 1
			}
		    }
		    if {!${ok}} {
			# Exit if there's a failure to avoid lengthy
			# timeouts.
			break
		    }

		    if {${non-stop}} {
			gdb_test -nopass "thread $thread" "Switching to thread .*" \
			    "switch to event thread"
		    }
		}
	    }
	}
    }
}

foreach_with_prefix step_over_mode {none inline displaced} {
    foreach_with_prefix non-stop {off on} {
	foreach_with_prefix target-non-stop {off on} {
	    if {${non-stop} == "on" && ${target-non-stop} == "off"} {
		# Invalid combination.
		continue
	    }

	    foreach_with_prefix schedlock {off on} {
		foreach_with_prefix cmd {"next" "continue"} {
		    if {${non-stop} == "on"} {
			foreach_with_prefix ns_stop_all {0 1} {
			    test ${step_over_mode} ${non-stop} ${target-non-stop} \
				${schedlock} ${cmd} ${ns_stop_all}
			}
		    } else {
			test ${step_over_mode} ${non-stop} ${target-non-stop} ${schedlock} ${cmd} 0
		    }
		}
	    }
	}
    }
}