gdb/testsuite/gdb.base/watch-read.exp

   1 # This testcase is part of GDB, the GNU debugger.
   2
   3 # Copyright 2010-2021 Free Software Foundation, Inc.
   4
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 # This file is part of the gdb testsuite.
  19
  20 #
  21 # Tests involving read watchpoints, and other kinds of watchpoints
  22 # watching the same memory as read watchpoints.
  23 #
  24
  25 standard_testfile .c
  26
  27 if {[skip_hw_watchpoint_access_tests]} {
  28     return 0
  29 }
  30
  31 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
  32     return -1
  33 }
  34
  35 if { ![runto_main] } then {
  36     fail "run to main"
  37     return
  38 }
  39
  40 set read_line [gdb_get_line_number "read line" $srcfile]
  41
  42 # Test running to a read of `global', with a read watchpoint set
  43 # watching it.
  44
  45 gdb_test "rwatch global" \
  46     "Hardware read watchpoint .*: global" \
  47     "set hardware read watchpoint on global variable"
  48
  49 # The first read is on entry to the loop.
  50
  51 gdb_test "continue" \
  52     "read watchpoint .*: global.*.*Value = 0.*in main.*$srcfile:$read_line.*" \
  53     "read watchpoint triggers on first read"
  54
  55 # The second read happens on second loop iteration, after `global'
  56 # having been incremented.  On architectures where gdb has to emulate
  57 # read watchpoints with access watchpoints, this tests the
  58 # only-report-if-value-changed logic.  On targets that support real
  59 # read watchpoints, this tests that GDB ignores the watchpoint's old
  60 # value, knowing that some untrapped write could have changed it, and
  61 # so reports the read watchpoint unconditionally.
  62
  63 gdb_test "continue" \
  64     "read watchpoint .*: global.*.*Value = 1.*in main.*$srcfile:$read_line.*" \
  65     "read watchpoint triggers on read after value changed"
  66
  67 # The following tests check that when the user sets a write or access
  68 # watchpoint watching the same memory as a read watchpoint, GDB also
  69 # applies the only-report-if-value-changed logic even on targets that
  70 # support real read watchpoints.
  71
  72 # The program should be stopped at the read line.  Set a write
  73 # watchpoint (leaving the read watchpoint) and continue.  Only the
  74 # write watchpoint should be reported as triggering.
  75
  76 gdb_test "watch global" \
  77     "atchpoint .*: global" \
  78     "set write watchpoint on global variable"
  79
  80 gdb_test "continue" \
  81     "atchpoint .*: global.*Old value = 1.*New value = 2.*" \
  82     "write watchpoint triggers"
  83
  84 set exp ""
  85 set exp "${exp}2.*read watchpoint.*keep y.*global.*breakpoint already hit 2 times.*"
  86 set exp "${exp}3.*watchpoint.*keep y.*global.*breakpoint already hit 1 time.*"
  87 gdb_test "info watchpoints" \
  88     "$exp" \
  89     "only write watchpoint triggers when value changes"
  90
  91 # The program is now stopped at the write line.  Continuing should
  92 # stop at the read line, and only the read watchpoint should be
  93 # reported as triggering.
  94
  95 gdb_test "continue" \
  96     "read watchpoint .*: global.*Value = 2.*in main.*$srcfile:$read_line.*" \
  97     "read watchpoint triggers when value doesn't change, trapping reads and writes"
  98
  99 set exp ""
 100 set exp "${exp}2.*read watchpoint.*keep y.*global.*breakpoint already hit 3 times.*"
 101 set exp "${exp}3.*watchpoint.*keep y.*global.*breakpoint already hit 1 time.*"
 102 gdb_test "info watchpoints" \
 103     "$exp" \
 104     "only read watchpoint triggers when value doesn't change"