1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
# This testcase is part of GDB, the GNU debugger.
# Copyright 2014-2016 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 is part of the gdb testsuite.
# Test that GDB presents a hardware watchpoint stop at the first
# instruction right after the instruction that changes memory.
#
# Some targets trigger a hardware watchpoint after the instruction
# that wrote memory executes, thus with the memory already changed and
# the PC pointing to the instruction after the instruction that wrote
# to memory. These targets are said to have "continuable"
# watchpoints, referring to the fact that to make progress after the
# watchpoint triggers, GDB just needs to continue the target.
#
# Other targets trigger a hardware watchpoint at the instruction which
# has attempted to write to the piece of memory under control of the
# watchpoint, with the instruction actually not executed yet. To be
# able to check whether the watched value changed, GDB needs to
# complete the memory write, single-stepping the target once. These
# targets are said to have "non-continuable" watchpoints.
#
# This test makes sure that GDB knows which kind of watchpoint the
# target has, using this sequence of steps:
#
# 1 - run to main
#
# 2 - set a software watchpoint
#
# 3 - continue until watchpoint triggers
#
# 4 - the PC now points to the instruction right after the instruction
# that actually caused the memory write. So this is the address a
# hardware watchpoint should present the stop to the user too.
# Store the PC address.
#
# 5 - replace the software watchpoint by a hardware watchpoint
#
# 6 - continue until hardware watchpoint triggers
#
# 7 - the PC must point to the same address the software watchpoint
# triggered at.
#
# If the target has continuable watchpoints, but GDB thinks it has
# non-continuable watchpoints, GDB will stop the inferior two
# instructions after the watched value change, rather than at the next
# instruction.
#
# If the target has non-continuable watchpoints, while GDB thinks it
# has continuable watchpoints, GDB will see a watchpoint trigger,
# notice no value changed, and immediatly continue the target. Now,
# either the target manages to step-over the watchpoint transparently,
# and GDB thus fails to present to value change to the user, or, the
# watchpoint will keep re-triggering, with the program never making
# any progress.
standard_testfile
# No use testing this if we can't use hardware watchpoints.
if {[target_info exists gdb,no_hardware_watchpoints]} {
return -1
}
if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
untested ${testfile}.exp
return -1
}
if { ![runto main] } then {
fail "run to main"
return
}
# Get the current PC. TEST is used as test prefix.
proc get_pc {test} {
global hex gdb_prompt
set addr ""
gdb_test_multiple "p /x \$pc" "$test" {
-re " = ($hex).*$gdb_prompt $" {
set addr $expect_out(1,string)
pass "$test"
}
}
return $addr
}
# So we get an immediate warning/error if the target doesn't support a
# given watchpoint type.
gdb_test_no_output "set breakpoint always-inserted on"
set hw_watchpoints_supported 0
set test "set probe hw watchpoint"
gdb_test_multiple "watch global" $test {
-re "You may have requested too many.*$gdb_prompt $" {
pass $test
}
-re "Target does not support.*$gdb_prompt $" {
pass $test
}
-re "$gdb_prompt $" {
pass $test
set hw_watchpoints_supported 1
}
}
if {!$hw_watchpoints_supported} {
unsupported "no hw watchpoints support"
return
}
delete_breakpoints
proc test {always_inserted} {
global srcfile binfile
with_test_prefix "always-inserted $always_inserted" {
clean_restart $binfile
if { ![runto main] } then {
fail "run to main"
return
}
# Force use of software watchpoints.
gdb_test_no_output "set can-use-hw-watchpoints 0"
gdb_test "watch global" \
"Watchpoint .*: global" \
"set software watchpoint on global variable"
gdb_test "continue" \
"Watchpoint .*: global.*Old value = 0.*New value = 1.*set_global \\(val=1\\).*$srcfile.*" \
"software watchpoint triggers"
set sw_watch_pc [get_pc "get sw watchpoint PC"]
delete_breakpoints
# Allow hardware watchpoints again.
gdb_test_no_output "set can-use-hw-watchpoints 1"
gdb_test "watch global" \
"Hardware watchpoint .*: global" \
"set hardware watchpoint on global variable"
gdb_test "continue" \
"Hardware watchpoint .*: global.*Old value = 1.*New value = 2.*set_global \\(val=2\\).*$srcfile.*" \
"hardware watchpoint triggers"
set hw_watch_pc [get_pc "get hw watchpoint PC"]
gdb_assert {$sw_watch_pc == $hw_watch_pc} "hw watchpoint stops at right instruction"
}
}
foreach always_inserted {"off" "on" } {
test $always_inserted
}
|
