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

   1 # Copyright (C) 2009, 2010, 2011 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 set testfile "pending-step"
  52 set srcfile ${testfile}.c
  53 set binfile ${objdir}/${subdir}/${testfile}
  54
  55 if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable [list debug "incdir=${objdir}"]] != "" } {
  56     return -1
  57 }
  58
  59 # Start with a fresh gdb.
  60
  61 gdb_exit
  62 gdb_start
  63 gdb_reinitialize_dir $srcdir/$subdir
  64 gdb_load ${binfile}
  65
  66 if ![runto_main] then {
  67     fail "Can't run to main"
  68     return 0
  69 }
  70
  71 gdb_breakpoint [gdb_get_line_number "insert breakpoint here"]
  72 gdb_continue_to_breakpoint "continue to first breakpoint hit"
  73
  74 set test "next in multiple threads with breakpoints"
  75 set iterations 20
  76 set ok 0
  77 for {set i 0} {$i < $iterations} {incr i} {
  78     set ok 0
  79     gdb_test_multiple "next" "$test" {
  80         -re "Program received signal SIGTRAP.*$gdb_prompt $" {
  81             fail "$test (spurious SIGTRAP)"
  82         }
  83         -re "$gdb_prompt $" {
  84             set ok 1
  85         }
  86     }
  87
  88     if { $ok == 0 } {
  89         break
  90     }
  91 }
  92
  93 if { $ok  } {
  94     pass "$test"
  95 }