1# This testcase is part of GDB, the GNU debugger.
2
3# Copyright 2010-2013 Free Software Foundation, Inc.
4
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation; either version 3 of the License, or
8# (at your option) any later version.
9#
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13# GNU General Public License for more details.
14#
15# You should have received a copy of the GNU General Public License
16# along with this program.  If not, see <http://www.gnu.org/licenses/>.
17
18# This file was written by Pedro Alves <pedro@codesourcery.com>
19
20# This file is part of the gdb testsuite.
21
22#
23# Tests involving read watchpoints, and other kinds of watchpoints
24# watching the same memory as read watchpoints.
25#
26
27set testfile "watch-read"
28set srcfile ${testfile}.c
29
30if {[skip_hw_watchpoint_access_tests]} {
31    return 0
32}
33
34if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
35    untested ${testfile}.exp
36    return -1
37}
38
39if { ![runto main] } then {
40    fail "run to main"
41    return
42}
43
44set read_line [gdb_get_line_number "read line" $srcfile]
45
46# Test running to a read of `global', with a read watchpoint set
47# watching it.
48
49gdb_test "rwatch global" \
50    "Hardware read watchpoint .*: global" \
51    "set hardware read watchpoint on global variable"
52
53# The first read is on entry to the loop.
54
55gdb_test "continue" \
56    "read watchpoint .*: global.*.*Value = 0.*in main.*$srcfile:$read_line.*" \
57    "read watchpoint triggers on first read"
58
59# The second read happens on second loop iteration, after `global'
60# having been incremented.  On architectures where gdb has to emulate
61# read watchpoints with access watchpoints, this tests the
62# only-report-if-value-changed logic.  On targets that support real
63# read watchpoints, this tests that GDB ignores the watchpoint's old
64# value, knowing that some untrapped write could have changed it, and
65# so reports the read watchpoint unconditionally.
66
67gdb_test "continue" \
68    "read watchpoint .*: global.*.*Value = 1.*in main.*$srcfile:$read_line.*" \
69    "read watchpoint triggers on read after value changed"
70
71# The following tests check that when the user sets a write or access
72# watchpoint watching the same memory as a read watchpoint, GDB also
73# applies the only-report-if-value-changed logic even on targets that
74# support real read watchpoints.
75
76# The program should be stopped at the read line.  Set a write
77# watchpoint (leaving the read watchpoint) and continue.  Only the
78# write watchpoint should be reported as triggering.
79
80gdb_test "watch global" \
81    "atchpoint .*: global" \
82    "set write watchpoint on global variable"
83
84gdb_test "continue" \
85    "atchpoint .*: global.*Old value = 1.*New value = 2.*" \
86    "write watchpoint triggers"
87
88set exp ""
89set exp "${exp}2.*read watchpoint.*keep y.*global.*breakpoint already hit 2 times.*"
90set exp "${exp}3.*watchpoint.*keep y.*global.*breakpoint already hit 1 time.*"
91gdb_test "info watchpoints" \
92    "$exp" \
93    "only write watchpoint triggers when value changes"
94
95# The program is now stopped at the write line.  Continuing should
96# stop at the read line, and only the read watchpoint should be
97# reported as triggering.
98
99gdb_test "continue" \
100    "read watchpoint .*: global.*Value = 2.*in main.*$srcfile:$read_line.*" \
101    "read watchpoint triggers when value doesn't change, trapping reads and writes"
102
103set exp ""
104set exp "${exp}2.*read watchpoint.*keep y.*global.*breakpoint already hit 3 times.*"
105set exp "${exp}3.*watchpoint.*keep y.*global.*breakpoint already hit 1 time.*"
106gdb_test "info watchpoints" \
107    "$exp" \
108    "only read watchpoint triggers when value doesn't change"
109