gdb/testsuite/gdb.threads/pending-step.exp

   1 # Copyright (C) 2009-2013 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 # Test that a resume cancels a previously unfinished or unreported
  17 # single-step correctly.
  18 #
  19 # The test consists of several threads all running the same loop.
  20 # There is a breakpoint set in the loop, hence all threads may hit it.
  21 # The test then issues several "next" commands in a loop.
  22 #
  23 # scheduler-locking must be set to the default of "off".
  24 #
  25 # Here's what would happen in gdbserver:
  26 #
  27 # 1) We issue a "continue", and wait until a thread hits the
  28 #    breakpoint.  Could be any thread, but assume thread 1 hits it.
  29 #
  30 # 2) We issue a "next" --- this single-steps thread 1, and resumes all
  31 #    other threads.
  32 #
  33 # 3) thread 2, due to scheduler-locking off, hits the breakpoint.
  34 #    gdbserver stops all other threads by sending them SIGSTOPs.
  35 #
  36 # 4) While being stopped in step 3, thread 1 reports a SIGTRAP, that
  37 #    corresponds to the finished single-step of step 2.  gdbserver
  38 #    leaves the SIGTRAP pending to report later.
  39 #
  40 # 5) We issue another "next" --- this requests thread 2 to
  41 #    single-step, and all other threads to continue, including thread
  42 #    1.  Before resuming any thread, gdbserver notices that it
  43 #    remembers from step 4 a pending SIGTRAP to report for thread 1,
  44 #    so reports it now.
  45 #
  46 # 6) From GDB's perpective, this SIGTRAP can't represent a finished
  47 #    single-step, since thread 1 was not single-stepping (it was
  48 #    continued in step 5).  Neither does this SIGTRAP correspond to a
  49 #    breakpoint hit.  GDB reports to the user a spurious SIGTRAP.
  50
  51 standard_testfile
  52
  53 if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable debug] != "" } {
  54     return -1
  55 }
  56
  57 clean_restart ${binfile}
  58
  59 if ![runto_main] then {
  60     fail "Can't run to main"
  61     return 0
  62 }
  63
  64 gdb_breakpoint [gdb_get_line_number "insert breakpoint here"]
  65 gdb_continue_to_breakpoint "continue to first breakpoint hit"
  66
  67 set test "next in multiple threads with breakpoints"
  68 set iterations 20
  69 set ok 0
  70 for {set i 0} {$i < $iterations} {incr i} {
  71     set ok 0
  72     gdb_test_multiple "next" "$test" {
  73         -re "Program received signal SIGTRAP.*$gdb_prompt $" {
  74             fail "$test (spurious SIGTRAP)"
  75         }
  76         -re "$gdb_prompt $" {
  77             set ok 1
  78         }
  79     }
  80
  81     if { $ok == 0 } {
  82         break
  83     }
  84 }
  85
  86 if { $ok  } {
  87     pass "$test"
  88 }