1# Copyright 1992-2023 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 skip_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 24set skip_hw_watchpoint_tests_p [skip_hw_watchpoint_tests] 25 26standard_testfile 27 28if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} { 29 return -1 30} 31 32proc recurse_tests {} { 33 34 # Disable hardware watchpoints if necessary. 35 global skip_hw_watchpoint_tests_p 36 37 if {$skip_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. 136set oldtimeout $timeout 137set timeout [expr "$timeout + 60"] 138verbose "Timeout is now $timeout seconds" 2 139 140recurse_tests 141 142# Restore the preserved old timeout value. 143set timeout $oldtimeout 144verbose "Timeout is now $timeout seconds" 2 145 146