gdb/testsuite/gdb.base/recurse.exp

   1 # Copyright 1992-2024 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 # This file was written by Jeff Law. (law@cs.utah.edu)
  17
  18 # The allow_hw_watchpoint_tests checks if watchpoints are supported by the
  19 # processor.  On PowerPC, the check runs a small test program under gdb
  20 # to determine if the Power processor supports HW watchpoints.  The check
  21 # must be done before starting the test so as to not disrupt the execution
  22 # of the actual test.
  23
  24 set allow_hw_watchpoint_tests_p [allow_hw_watchpoint_tests]
  25
  26 standard_testfile
  27
  28 if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
  29     return -1
  30 }
  31
  32 proc recurse_tests {} {
  33
  34     # Disable hardware watchpoints if necessary.
  35     global allow_hw_watchpoint_tests_p
  36
  37     if {!$allow_hw_watchpoint_tests_p} {
  38          gdb_test_no_output "set can-use-hw-watchpoints 0" ""
  39     }
  40
  41     if {[runto recurse]} {
  42         # First we need to step over the assignment of b, so it has a known
  43         # value.
  44         gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in first instance"
  45         gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
  46             "set first instance watchpoint"
  47
  48         # Continue until initial set of b.
  49         gdb_test "continue" \
  50             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 10.*" \
  51             "continue to first instance watchpoint, first time"
  52
  53         # Continue inward for a few iterations
  54         gdb_test "continue" "Breakpoint.* recurse \\(a=9\\).*" \
  55             "continue to recurse (a = 9)"
  56         gdb_test "continue" "Breakpoint.* recurse \\(a=8\\).*" \
  57             "continue to recurse (a = 8)"
  58         gdb_test "continue" "Breakpoint.* recurse \\(a=7\\).*" \
  59             "continue to recurse (a = 7)"
  60         gdb_test "continue" "Breakpoint.* recurse \\(a=6\\).*" \
  61             "continue to recurse (a = 6)"
  62         gdb_test "continue" "Breakpoint.* recurse \\(a=5\\).*" \
  63             "continue to recurse (a = 5)"
  64
  65         # Put a watchpoint on another instance of b
  66         # First we need to step over the assignment of b, so it has a known
  67         # value.
  68         gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in second instance"
  69         gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
  70             "set second instance watchpoint"
  71
  72         # Continue until initial set of b (second instance).
  73         gdb_test "continue" \
  74             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 5.*"\
  75             "continue to second instance watchpoint, first time"
  76
  77         # Continue inward for a few iterations
  78         gdb_test "continue" "Breakpoint.* recurse \\(a=4\\).*" \
  79             "continue to recurse (a = 4)"
  80         gdb_test "continue" "Breakpoint.* recurse \\(a=3\\).*" \
  81             "continue to recurse (a = 3)"
  82         gdb_test "continue" "Breakpoint.* recurse \\(a=2\\).*" \
  83             "continue to recurse (a = 2)"
  84         gdb_test "continue" "Breakpoint.* recurse \\(a=1\\).*" \
  85             "continue to recurse (a = 1)"
  86
  87         # Continue until second set of b (second instance).
  88         gdb_test "continue" \
  89             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 5.*New value = 120.*return.*" \
  90             "continue to second instance watchpoint, second time"
  91
  92         # Continue again.  We should have a watchpoint go out of scope now
  93         gdb_test "continue" \
  94             "Continuing.*\[Ww\]atchpoint.*deleted.*recurse \\(a=6\\) .*" \
  95             "second instance watchpoint deleted when leaving scope"
  96
  97         # Continue until second set of b (first instance).
  98         # 24320 is allowed as the final value for b as that's the value
  99         # b would have on systems with 16bit integers.
 100         #
 101         # We could fix the test program to deal with this too.
 102         gdb_test "continue" \
 103             "Continuing.*\[Ww\]atchpoint.*b.*Old value = 10.*New value = \(3628800|24320\).*return.*" \
 104             "continue to first instance watchpoint, second time"
 105
 106         # Continue again.  We should have a watchpoint go out of scope now.
 107         #
 108         # The former version expected the test to return to main().
 109         # Now it expects the test to return to main or to stop in the
 110         # function's epilogue.
 111         #
 112         # The problem is that gdb needs to (but doesn't) understand
 113         # function epilogues in the same way as for prologues.
 114         #
 115         # If there is no hardware watchpoint (such as a x86 debug register),
 116         # then watchpoints are done "the hard way" by single-stepping the
 117         # target until the value of the watched variable changes.  If you
 118         # are single-stepping, you will eventually step into an epilogue.
 119         # When you do that, the "top" stack frame may become partially
 120         # deconstructed (as when you pop the frame pointer, for instance),
 121         # and from that point on, GDB can no longer make sense of the stack.
 122         #
 123         # A test which stops in the epilogue is trying to determine when GDB
 124         # leaves the stack frame in which the watchpoint was created.  It does
 125         # this basically by watching for the frame pointer to change.  When
 126         # the frame pointer changes, the test expects to be back in main, but
 127         # instead it is still in the epilogue of the callee.
 128         gdb_test "continue" \
 129             "Continuing.*\[Ww\]atchpoint.*deleted.*\(main \\(\\) \|21.*\}\).*" \
 130             "first instance watchpoint deleted when leaving scope"
 131     }
 132 }
 133
 134 # Preserve the old timeout, and set a new one that should be
 135 # sufficient to avoid timing out during this test.
 136 set oldtimeout $timeout
 137 set timeout [expr "$timeout + 60"]
 138 verbose "Timeout is now $timeout seconds" 2
 139
 140 recurse_tests
 141
 142 # Restore the preserved old timeout value.
 143 set timeout $oldtimeout
 144 verbose "Timeout is now $timeout seconds" 2
 145