gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.exp

   1 # Copyright (C) 2014-2021 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 # On decr_pc_after_break targets, GDB used to adjust the PC
  17 # incorrectly if a background single-step stopped somewhere where
  18 # PC-$decr_pc had a breakpoint, and the thread was not the current
  19 # thread, like:
  20 #
  21 #   ADDR1 nop <-- breakpoint here
  22 #   ADDR2 jmp PC
  23 #
  24 #  IOW, say thread A is stepping ADDR2's line in the background (an
  25 #  infinite loop), and the user switches focus to thread B.  GDB's
  26 #  adjust_pc_after_break logic would confuse the single-step stop of
  27 #  thread A for a hit of the breakpoint at ADDR1, and thus adjust
  28 #  thread A's PC to point at ADDR1 when it should not: the thread had
  29 #  been single-stepped, not continued.
  30
  31 standard_testfile
  32
  33 if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
  34     return -1
  35 }
  36
  37 clean_restart $binfile
  38
  39 if ![runto_main] {
  40     continue
  41 }
  42
  43 # Make sure it's GDB's decr_pc logic that's being tested, not the
  44 # target's.
  45 gdb_test_no_output "set range-stepping off"
  46
  47 delete_breakpoints
  48
  49 gdb_breakpoint [gdb_get_line_number "set breakpoint here"]
  50 gdb_continue_to_breakpoint "run to nop breakpoint"
  51 gdb_test "info threads" "  1 .*\\\* 2 .*" "info threads shows all threads"
  52
  53 gdb_test "next" "while.*" "next over nop"
  54
  55 gdb_test_no_output "next&" "next& over inf loop"
  56
  57 set test "switch to main thread"
  58 gdb_test_multiple "thread 1" $test {
  59     -re "Cannot execute this command while the target is running.*$gdb_prompt $" {
  60         unsupported $test
  61
  62         # With remote targets, we can't send any other remote packet
  63         # until the target stops.  Switching thread wants to ask the
  64         # remote side whether the thread is alive.
  65         return
  66     }
  67     -re "Switching to thread 1.*\\(running\\)\r\n$gdb_prompt " {
  68         # Prefer to match the prompt without an anchor.  If there's a
  69         # bug and output comes after the prompt immediately, it's
  70         # faster to handle that in the following test, instead of
  71         # waiting for a timeout here.
  72         pass $test
  73     }
  74 }
  75
  76 # Wait a bit.  Use gdb_expect instead of sleep so that any (bad) GDB
  77 # output is visible in the log.
  78 gdb_expect 4 {}
  79
  80 set test "no output while stepping"
  81 gdb_test_multiple "" $test {
  82     -timeout 1
  83     timeout {
  84         pass $test
  85     }
  86     -re "." {
  87         # If we see any output, it's a failure.  On the original bug,
  88         # this would be a breakpoint hit.
  89         fail $test
  90     }
  91 }