gdb/testsuite/gdb.base/recurse.exp

   1 # Copyright 1992-2022 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 # This file was written by Jeff Law. (law@cs.utah.edu)
  17
  18
  19 standard_testfile
  20
  21 if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
  22     return -1
  23 }
  24
  25 proc recurse_tests {} {
  26
  27     # Disable hardware watchpoints if necessary.
  28     if [target_info exists gdb,no_hardware_watchpoints] {
  29         gdb_test_no_output "set can-use-hw-watchpoints 0" ""
  30     }
  31
  32     if [runto recurse] then {
  33         # First we need to step over the assignment of b, so it has a known
  34         # value.
  35         gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in first instance"
  36         gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
  37             "set first instance watchpoint"
  38
  39         # Continue until initial set of b.
  40         gdb_test "continue" \
  41             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 10.*" \
  42             "continue to first instance watchpoint, first time"
  43
  44         # Continue inward for a few iterations
  45         gdb_test "continue" "Breakpoint.* recurse \\(a=9\\).*" \
  46             "continue to recurse (a = 9)"
  47         gdb_test "continue" "Breakpoint.* recurse \\(a=8\\).*" \
  48             "continue to recurse (a = 8)"
  49         gdb_test "continue" "Breakpoint.* recurse \\(a=7\\).*" \
  50             "continue to recurse (a = 7)"
  51         gdb_test "continue" "Breakpoint.* recurse \\(a=6\\).*" \
  52             "continue to recurse (a = 6)"
  53         gdb_test "continue" "Breakpoint.* recurse \\(a=5\\).*" \
  54             "continue to recurse (a = 5)"
  55
  56         # Put a watchpoint on another instance of b
  57         # First we need to step over the assignment of b, so it has a known
  58         # value.
  59         gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in second instance"
  60         gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
  61             "set second instance watchpoint"
  62
  63         # Continue until initial set of b (second instance).
  64         gdb_test "continue" \
  65             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 5.*"\
  66             "continue to second instance watchpoint, first time"
  67
  68         # Continue inward for a few iterations
  69         gdb_test "continue" "Breakpoint.* recurse \\(a=4\\).*" \
  70             "continue to recurse (a = 4)"
  71         gdb_test "continue" "Breakpoint.* recurse \\(a=3\\).*" \
  72             "continue to recurse (a = 3)"
  73         gdb_test "continue" "Breakpoint.* recurse \\(a=2\\).*" \
  74             "continue to recurse (a = 2)"
  75         gdb_test "continue" "Breakpoint.* recurse \\(a=1\\).*" \
  76             "continue to recurse (a = 1)"
  77
  78         # Continue until second set of b (second instance).
  79         gdb_test "continue" \
  80             "Continuing.*\[Ww\]atchpoint.*: b.*Old value = 5.*New value = 120.*return.*" \
  81             "continue to second instance watchpoint, second time"
  82
  83         # Continue again.  We should have a watchpoint go out of scope now
  84         gdb_test "continue" \
  85             "Continuing.*\[Ww\]atchpoint.*deleted.*recurse \\(a=6\\) .*" \
  86             "second instance watchpoint deleted when leaving scope"
  87
  88         # Continue until second set of b (first instance).
  89         # 24320 is allowed as the final value for b as that's the value
  90         # b would have on systems with 16bit integers.
  91         #
  92         # We could fix the test program to deal with this too.
  93         gdb_test "continue" \
  94             "Continuing.*\[Ww\]atchpoint.*b.*Old value = 10.*New value = \(3628800|24320\).*return.*" \
  95             "continue to first instance watchpoint, second time"
  96
  97         # Continue again.  We should have a watchpoint go out of scope now.
  98         #
  99         # The former version expected the test to return to main().
 100         # Now it expects the test to return to main or to stop in the
 101         # function's epilogue.
 102         #
 103         # The problem is that gdb needs to (but doesn't) understand
 104         # function epilogues in the same way as for prologues.
 105         #
 106         # If there is no hardware watchpoint (such as a x86 debug register),
 107         # then watchpoints are done "the hard way" by single-stepping the
 108         # target until the value of the watched variable changes.  If you
 109         # are single-stepping, you will eventually step into an epilogue.
 110         # When you do that, the "top" stack frame may become partially
 111         # deconstructed (as when you pop the frame pointer, for instance),
 112         # and from that point on, GDB can no longer make sense of the stack.
 113         #
 114         # A test which stops in the epilogue is trying to determine when GDB
 115         # leaves the stack frame in which the watchpoint was created.  It does
 116         # this basically by watching for the frame pointer to change.  When
 117         # the frame pointer changes, the test expects to be back in main, but
 118         # instead it is still in the epilogue of the callee.
 119         gdb_test "continue" \
 120             "Continuing.*\[Ww\]atchpoint.*deleted.*\(main \\(\\) \|21.*\}\).*" \
 121             "first instance watchpoint deleted when leaving scope"
 122     }
 123 }
 124
 125 # Preserve the old timeout, and set a new one that should be
 126 # sufficient to avoid timing out during this test.
 127 set oldtimeout $timeout
 128 set timeout [expr "$timeout + 60"]
 129 verbose "Timeout is now $timeout seconds" 2
 130
 131 recurse_tests
 132
 133 # Restore the preserved old timeout value.
 134 set timeout $oldtimeout
 135 verbose "Timeout is now $timeout seconds" 2
 136