testsuite/gdb.threads/tls.exp

# tls.exp -- Expect script to test thread-local storage
# Copyright (C) 1992-2020 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/>.  */

load_lib gdb-python.exp

standard_testfile tls.c tls2.c

if [istarget "*-*-linux"] then {
    set target_cflags "-D_MIT_POSIX_THREADS"
} else {
    set target_cflags ""
}

if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile} ${srcdir}/${subdir}/${srcfile2}" "${binfile}" executable [list c++ debug]] != "" } {
    return -1
}

### Compute the value of the a_thread_local variable.
proc compute_expected_value {value} {
    set expected_value 0
    set i 0
    while { $i <= $value} {
        incr expected_value $i
        incr i
    }
    return $expected_value
}

### Get the value of the variable 'me' for the current thread.
proc get_me_variable {tnum} {
    global expect_out
    global gdb_prompt
    global decimal

    set value_of_me -1
    send_gdb "print me\n"
    gdb_expect {
	-re ".*= ($decimal).*\r\n$gdb_prompt $" {
	    set value_of_me $expect_out(1,string)
	    pass "$tnum thread print me"
        }
	-re "$gdb_prompt $" {
	    fail "$tnum thread print me"
	}
	timeout {
	    fail "$tnum thread print me (timeout)"
	}
    }
    return ${value_of_me}
}

### Check the values of the thread local variables in the thread.
### Also check that info address print the right things.
proc check_thread_local {number} {
    set me_variable [get_me_variable $number]
    set expected_value [compute_expected_value ${me_variable}]

    gdb_test "p a_thread_local" \
	    "= $expected_value" \
	    "${number} thread local storage"

    if {![skip_python_tests]} {
	gdb_test_no_output \
	    "python sym = gdb.lookup_symbol('a_thread_local')\[0\]" \
	    "${number} look up a_thread_local symbol"
	# We intentionally do not pass a frame to "value" here.  If a
	# TLS variable requires a frame, this will fail.  However, if
	# it does not require a frame, then it will succeed.
	gdb_test "python print(sym.value())" "$expected_value" \
	    "${number} get symbol value without frame"
    }

    gdb_test "p K::another_thread_local" \
	    "= $me_variable" \
	    "${number} another thread local storage"

    gdb_test "info address a_thread_local" \
	    ".*a_thread_local.*a thread-local variable at offset.*" \
	    "${number} info address a_thread_local"

    gdb_test "info address K::another_thread_local" \
    	    ".*another_thread_local.*a thread-local variable at offset.*" \
	    "${number} info address another_thread_local"
}

### Select a particular thread.
proc select_thread {thread} {
    global gdb_prompt

    send_gdb "thread $thread\n"
    gdb_expect {
	-re "\\\[Switching to thread .*\\\].*\r\n$gdb_prompt $" {
	    pass "selected thread: $thread"
	}
	-re "$gdb_prompt $" {
	    fail "selected thread: $thread"
	}
	timeout {
	    fail "selected thread: $thread (timeout)"
	}
    }
}

### Do a backtrace for the current thread, and check that the 'spin' routine
### is in it. This means we have one of the threads we created, rather
### than the main thread. Record the thread in the spin_threads
### array. Also remember the level of the 'spin' routine in the backtrace, for
### later use.
proc check_thread_stack {number spin_threads spin_threads_level} {
    global gdb_prompt
    global expect_out
    global decimal
    global hex
    upvar $spin_threads tarr
    upvar $spin_threads_level tarrl

    select_thread $number
    send_gdb "where\n"
    gdb_expect {
	-re ".*(\[0-9\]+)\[ \t\]+$hex in spin \\(vp=(0x\[0-9a-f\]+).*\r\n$gdb_prompt $" {
	    if {[info exists tarr($number)]} {
		fail "backtrace of thread number $number in spin"
	    } else {
		pass "backtrace of thread number $number in spin"
                set level $expect_out(1,string)
		set tarrl($number) $level
		set tarr($number) 1
	    }
	}
	-re ".*$gdb_prompt $" {
	 set tarr($number) 0
	 set tarrl($number) 0
	 pass "backtrace of thread number $number not relevant"
	}
	timeout {
	    fail "backtrace of thread number $number (timeout)"
	}
    }
}

clean_restart ${binfile}

gdb_test_multiple "print a_thread_local" "" {
    -re -wrap "Cannot find thread-local variables on this target" {
	kfail "gdb/25807" $gdb_test_name
    }
    -re -wrap "Cannot read .a_thread_local. without registers" {
	pass $gdb_test_name
    }
}

if ![runto_main] then {
   fail "can't run to main"
   return 0
}

# Set a breakpoint at the "spin" routine to
# test the thread local's value.
#
gdb_test "b [gdb_get_line_number "here we know tls value"]" \
         ".*Breakpoint 2.*tls.*"   "set breakpoint at all threads"

# Set a bp at a point where we know all threads are alive.
#
gdb_test "b [gdb_get_line_number "still alive"]" \
         ".*Breakpoint 3.*tls.*" "set breakpoint at synch point"

# Set a bp at the end to see if all threads are finished.
#
gdb_test "b [gdb_get_line_number "before exit"]" \
         ".*Breakpoint 4.*tls.*" "set breakpoint at exit"

send_gdb "continue\n"
gdb_expect {
    -re ".* received signal SIGSEGV.*a_thread_local = 0;.*$gdb_prompt $" {
        # This is the first symptom if the gcc and binutils versions
        # in use support TLS, but the system glibc does not.
        unsupported "continue to first thread: system does not support TLS"
        return -1
    }
    -re ".*$inferior_exited_re normally.*$gdb_prompt $" {
        fail "continue to first thread: program runaway"
    }
    -re ".*Pass 0 done.*Pass 1 done.*$gdb_prompt $" {
        fail "continue to first thread: program runaway 2"
    }
    -re ".*Breakpoint 2.*tls value.*$gdb_prompt $" {
        pass "continue to first thread: get to thread"
    }
    -re ".*$gdb_prompt $" {
        fail "continue to first thread: no progress?"
    }
    timeout { fail "continue to first thread (timeout)" }
}

gdb_test "info thread" ".*Thread.*spin.*" \
	"at least one th in spin while stopped at first th"

check_thread_local "first"

gdb_test "continue" ".*Breakpoint 2.*tls value.*" "continue to second thread"
gdb_test "info thread" "Thread.*spin.*" \
	"at least one th in spin while stopped at second th"

check_thread_local "second"

gdb_test "continue" ".*Breakpoint 2.*tls value.*" "continue to third thread"
gdb_test "info thread" ".*Thread.*spin.*" \
	"at least one th in spin while stopped at third th"

check_thread_local "third"

gdb_test "continue" ".*Breakpoint 3.*still alive.*" "continue to synch point"

set no_of_threads 0
send_gdb "info thread\n"
gdb_expect {
    -re "^info thread\[ \t\r\n\]+ *Id .*Frame\[ \t\r\n\]+.*(\[0-9\]+) *Thread\[^\r\n\]+\r\n$gdb_prompt $" {
	   set no_of_threads $expect_out(1,string)
	   pass "get number of threads"
        }
	-re "$gdb_prompt $" {
	    fail "get number of threads"
	}
	timeout {
	    fail "get number of threads (timeout)"
	}
}

array set spin_threads {}
unset spin_threads
array set spin_threads_level {}
unset spin_threads_level

# For each thread check its backtrace to see if it is stopped at the
# spin routine.
for {set i 1} {$i <= $no_of_threads} {incr i} {
    check_thread_stack $i spin_threads spin_threads_level
}

### Loop through the threads and check the values of the tls variables.
### keep track of how many threads we find in the spin routine.
set thrs_in_spin 0
foreach i [array names spin_threads] {
    if {$spin_threads($i) == 1} {
      incr thrs_in_spin
      select_thread $i
      set level $spin_threads_level($i)
      # We expect to be in sem_wait, but if the thread has not yet
      # been scheduled, we might be in sem_post still.  We could be at
      # any intermediate point in spin, too, but that is much less
      # likely.
      gdb_test "up $level" ".*spin.*sem_(wait|post).*" "thread $i up"
      check_thread_local $i
    }
}

if {$thrs_in_spin == 0} {
  fail "no thread backtrace reported spin (vsyscall kernel problem?)"
}

gdb_test "continue" ".*Breakpoint 4.*before exit.*" "threads exited"

send_gdb "info thread\n"
gdb_expect {
    -re ".* 1 *Thread.*2 *Thread.*$gdb_prompt $" {
        fail "too many threads left at end"
    }
    -re ".*\\\* 1 *Thread.*main.*$gdb_prompt $" {
        pass "expect only base thread at end"
    }
    -re ".*No stack.*$gdb_prompt $" {
        fail "runaway at end"
    }
    -re ".*$gdb_prompt $" {
        fail "mess at end"
    }
    timeout { fail "at end (timeout)" }
}

# Start over and do some "info address" stuff
#
runto spin

gdb_test "info address a_global" \
	".*a_global.*static storage at address.*"

gdb_test "info address me" ".*me.*is a (complex DWARF expression:|variable).*"


# Test LOC_UNRESOLVED references resolving for `extern' TLS variables.

gdb_test "p a_thread_local" " = \[0-9\]+"
# Here it could crash with: Cannot access memory at address 0x0
gdb_test "p file2_thread_local" " = \[0-9\]+"
# Depending on the current lookup scope we get LOC_UNRESOLVED or LOC_COMPUTED
# both printing:
# Symbol "file2_thread_local" is a thread-local variable at offset 8 in the thread-local storage for `.../gdb.threads/tls'.
gdb_test "info address file2_thread_local" "Symbol \"file2_thread_local\" is a thread-local variable.*"
# Here it could also crash with: Cannot access memory at address 0x0
gdb_test "p a_thread_local" " = \[0-9\]+" "p a_thread_local second time"
gdb_test "info address a_thread_local" "Symbol \"a_thread_local\" is a thread-local variable.*"

# Done!
#
gdb_exit

return 0