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# Copyright 1992-2022 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This file was written by Jeff Law. (law@cs.utah.edu)
# The skip_hw_watchpoint_tests checks if watchpoints are supported by the
# processor. On PowerPC, the check runs a small test program under gdb
# to determine if the Power processor supports HW watchpoints. The check
# must be done before starting the test so as to not disrupt the execution
# of the actual test.
set skip_hw_watchpoint_tests_p [skip_hw_watchpoint_tests]
standard_testfile
if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
return -1
}
proc recurse_tests {} {
# Disable hardware watchpoints if necessary.
global skip_hw_watchpoint_tests_p
if {$skip_hw_watchpoint_tests_p} {
gdb_test_no_output "set can-use-hw-watchpoints 0" ""
}
if [runto recurse] then {
# First we need to step over the assignment of b, so it has a known
# value.
gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in first instance"
gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
"set first instance watchpoint"
# Continue until initial set of b.
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 10.*" \
"continue to first instance watchpoint, first time"
# Continue inward for a few iterations
gdb_test "continue" "Breakpoint.* recurse \\(a=9\\).*" \
"continue to recurse (a = 9)"
gdb_test "continue" "Breakpoint.* recurse \\(a=8\\).*" \
"continue to recurse (a = 8)"
gdb_test "continue" "Breakpoint.* recurse \\(a=7\\).*" \
"continue to recurse (a = 7)"
gdb_test "continue" "Breakpoint.* recurse \\(a=6\\).*" \
"continue to recurse (a = 6)"
gdb_test "continue" "Breakpoint.* recurse \\(a=5\\).*" \
"continue to recurse (a = 5)"
# Put a watchpoint on another instance of b
# First we need to step over the assignment of b, so it has a known
# value.
gdb_test "next" "if \\(a == 1\\)" "next over b = 0 in second instance"
gdb_test "watch b" ".*\[Ww\]atchpoint \[0-9]*: b" \
"set second instance watchpoint"
# Continue until initial set of b (second instance).
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*: b.*Old value = 0.*New value = 5.*"\
"continue to second instance watchpoint, first time"
# Continue inward for a few iterations
gdb_test "continue" "Breakpoint.* recurse \\(a=4\\).*" \
"continue to recurse (a = 4)"
gdb_test "continue" "Breakpoint.* recurse \\(a=3\\).*" \
"continue to recurse (a = 3)"
gdb_test "continue" "Breakpoint.* recurse \\(a=2\\).*" \
"continue to recurse (a = 2)"
gdb_test "continue" "Breakpoint.* recurse \\(a=1\\).*" \
"continue to recurse (a = 1)"
# Continue until second set of b (second instance).
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*: b.*Old value = 5.*New value = 120.*return.*" \
"continue to second instance watchpoint, second time"
# Continue again. We should have a watchpoint go out of scope now
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*deleted.*recurse \\(a=6\\) .*" \
"second instance watchpoint deleted when leaving scope"
# Continue until second set of b (first instance).
# 24320 is allowed as the final value for b as that's the value
# b would have on systems with 16bit integers.
#
# We could fix the test program to deal with this too.
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*b.*Old value = 10.*New value = \(3628800|24320\).*return.*" \
"continue to first instance watchpoint, second time"
# Continue again. We should have a watchpoint go out of scope now.
#
# The former version expected the test to return to main().
# Now it expects the test to return to main or to stop in the
# function's epilogue.
#
# The problem is that gdb needs to (but doesn't) understand
# function epilogues in the same way as for prologues.
#
# If there is no hardware watchpoint (such as a x86 debug register),
# then watchpoints are done "the hard way" by single-stepping the
# target until the value of the watched variable changes. If you
# are single-stepping, you will eventually step into an epilogue.
# When you do that, the "top" stack frame may become partially
# deconstructed (as when you pop the frame pointer, for instance),
# and from that point on, GDB can no longer make sense of the stack.
#
# A test which stops in the epilogue is trying to determine when GDB
# leaves the stack frame in which the watchpoint was created. It does
# this basically by watching for the frame pointer to change. When
# the frame pointer changes, the test expects to be back in main, but
# instead it is still in the epilogue of the callee.
gdb_test "continue" \
"Continuing.*\[Ww\]atchpoint.*deleted.*\(main \\(\\) \|21.*\}\).*" \
"first instance watchpoint deleted when leaving scope"
}
}
# Preserve the old timeout, and set a new one that should be
# sufficient to avoid timing out during this test.
set oldtimeout $timeout
set timeout [expr "$timeout + 60"]
verbose "Timeout is now $timeout seconds" 2
recurse_tests
# Restore the preserved old timeout value.
set timeout $oldtimeout
verbose "Timeout is now $timeout seconds" 2
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