gdb/testsuite/gdb.opt/break-on-_exit.exp

   1 # Copyright 2021-2022 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 # Set a breakpoint on libc's _exit, and verify that it triggers.  The function
  17 # tends to do a syscall immediately after the prologue, and if the breakpoint is
  18 # set past the syscall due to faulty prologue skipping, the breakpoint will not
  19 # trigger.
  20 #
  21 # In particular, we're trying to excercise the instruction analysis
  22 # functionality of prologue skipping.  If the non-minimal symbols are
  23 # read for libc, then that functionality might not be used because f.i.
  24 # line-info is used instead.  Also, if the minimal symbols are not read
  25 # for libc, then the breakpoint is set on the exec-local _exit@plt instead,
  26 # and that functionality will also not be used.
  27 #
  28 # We may get the required setup in case of a libc with misssing separate
  29 # debuginfo, but we want the same effect if that debuginfo is installed.
  30 #
  31 # So, we use -readnever to read minimal symbols, but not non-miminal symbols.
  32 #
  33 # Because the code at _exit may be and usually is optimized, the test is in
  34 # the gdb.opt directory.
  35
  36 standard_testfile
  37
  38 # See if we have target board readnow.exp or similar.
  39 if { [lsearch -exact $GDBFLAGS -readnow] != -1 \
  40          || [lsearch -exact $GDBFLAGS --readnow] != -1 } {
  41     untested "--readnever not allowed in combination with --readnow"
  42     return -1
  43 }
  44
  45 save_vars { GDBFLAGS } {
  46     append GDBFLAGS " -readnever"
  47
  48     if {[prepare_for_testing "failed to prepare" $testfile $srcfile nodebug]} {
  49         return -1
  50     }
  51 }
  52
  53 if ![runto_main] then {
  54     return 0
  55 }
  56
  57 gdb_breakpoint "_exit"
  58
  59 # Give some background information about the breakpoint(s) and corresponding
  60 # the shared lib(s).
  61 gdb_test "info breakpoints"
  62 gdb_test "info shared"
  63
  64 # If the skip_prologue analysis of _exit is too eager, we may not hit the
  65 # breakpoint.
  66 gdb_continue_to_breakpoint "_exit" "_exit \\(\\) .*"