1 # This testcase is part of GDB, the GNU debugger.
3 # Copyright 2004-2005, 2007-2012 Free Software Foundation, Inc.
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.
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.
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/>.
18 # Check that GDB can and only executes single instructions when
19 # stepping through a sequence of breakpoints interleaved by a signal
22 # This test is known to tickle the following problems: kernel letting
23 # the inferior execute both the system call, and the instruction
24 # following, when single-stepping a system call; kernel failing to
25 # propogate the single-step state when single-stepping the sigreturn
26 # system call, instead resuming the inferior at full speed; GDB
27 # doesn't know how to software single-step across a sigreturn
28 # instruction. Since the kernel problems can be "fixed" using
29 # software single-step this is KFAILed rather than XFAILed.
31 if [target_info exists gdb,nosignals] {
32 verbose "Skipping sigbpt.exp because of nosignals."
38 set srcfile ${testfile}.c
39 set binfile ${objdir}/${subdir}/${testfile}
40 if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
47 gdb_reinitialize_dir $srcdir/$subdir
51 # Run to `main' where we begin our tests.
54 if ![runto_main] then {
58 # If we can examine what's at memory address 0, it is possible that we
59 # could also execute it. This could probably make us run away,
60 # executing random code, which could have all sorts of ill effects,
61 # especially on targets without an MMU. Don't run the tests in that
64 gdb_test_multiple "x 0" "memory at address 0" {
65 -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
66 -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
67 -re ".*$gdb_prompt $" {
68 untested "Memory at address 0 is possibly executable"
73 gdb_test "break keeper"
75 # Run to bowler, and then single step until there's a SIGSEGV. Record
76 # the address of each single-step instruction (up to and including the
77 # instruction that causes the SIGSEGV) in bowler_addrs, and the address
78 # of the actual SIGSEGV in segv_addr.
79 # Note: this test detects which signal is received. Usually it is SIGSEGV
80 # (and we use SIGSEGV in comments) but on Darwin it is SIGBUS.
82 set bowler_addrs bowler
84 gdb_test {display/i $pc}
85 gdb_test "advance *bowler" "bowler.*" "advance to the bowler"
86 set test "stepping to fault"
88 gdb_test_multiple "stepi" "$test" {
89 -re "Program received signal (SIGBUS|SIGSEGV).*pc(\r\n| *) *=> (0x\[0-9a-f\]*).*$gdb_prompt $" {
90 set signame $expect_out(1,string)
91 set segv_addr $expect_out(3,string)
94 -re " .*pc(\r\n| *)=> (0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
95 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
101 # Now record the address of the instruction following the faulting
102 # instruction in bowler_addrs.
104 set test "get insn after fault"
105 gdb_test_multiple {x/2i $pc} "$test" {
106 -re "=> (0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
107 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
112 # Procedures for returning the address of the instruction before, at
113 # and after, the faulting instruction.
115 proc before_segv { } {
117 return [lindex $bowler_addrs 2]
122 return [lindex $bowler_addrs 1]
125 proc after_segv { } {
127 return [lindex $bowler_addrs 0]
130 # Check that the address table and SIGSEGV correspond.
132 set test "Verify that ${signame} occurs at the last STEPI insn"
133 if {[string compare $segv_addr [at_segv]] == 0} {
136 fail "$test ($segv_addr [at_segv])"
139 # Check that the inferior is correctly single stepped all the way back
140 # to a faulting instruction.
142 proc stepi_out { name args } {
146 # Set SIGSEGV to pass+nostop and then run the inferior all the way
147 # through to the signal handler. With the handler is reached,
148 # disable SIGSEGV, ensuring that further signals stop the
149 # inferior. Stops a SIGSEGV infinite loop when a broke system
150 # keeps re-executing the faulting instruction.
152 gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
153 gdb_test "continue" "keeper.*" "${name}; continue to keeper"
154 gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
156 # Insert all the breakpoints. To avoid the need to step over
157 # these instructions, this is delayed until after the keeper has
159 for {set i 0} {$i < [llength $args]} {incr i} {
160 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
161 "${name}; set breakpoint $i of [llength $args]"
164 # Single step our way out of the keeper, through the signal
165 # trampoline, and back to the instruction that faulted.
166 set test "${name}; stepi out of handler"
167 gdb_test_multiple "stepi" "$test" {
168 -re "Could not insert single-step breakpoint.*$gdb_prompt $" {
169 setup_kfail gdb/1736 "sparc*-*-openbsd*"
170 fail "$test (could not insert single-step breakpoint)"
172 -re "keeper.*$gdb_prompt $" {
176 -re "signal handler.*$gdb_prompt $" {
180 -re "Program received signal SIGSEGV.*$gdb_prompt $" {
181 kfail gdb/1702 "$test (executed fault insn)"
183 -re "Breakpoint.*pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
184 pass "$test (at breakpoint)"
186 -re "Breakpoint.*pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
187 kfail gdb/1702 "$test (executed breakpoint)"
189 -re "pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
192 -re "pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
193 kfail gdb/1702 "$test (skipped fault insn)"
195 -re "pc(\r\n| *)=> 0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {
196 kfail gdb/1702 "$test (corrupt pc)"
200 # Clear any breakpoints
201 for {set i 0} {$i < [llength $args]} {incr i} {
202 gdb_test "clear [lindex $args $i]" "Deleted .*" \
203 "${name}; clear breakpoint $i of [llength $args]"
207 # Let a signal handler exit, returning to a breakpoint instruction
208 # inserted at the original fault instruction. Check that the
209 # breakpoint is hit, and that single stepping off that breakpoint
210 # executes the underlying fault instruction causing a SIGSEGV.
212 proc cont_out { name args } {
216 # Set SIGSEGV to pass+nostop and then run the inferior all the way
217 # through to the signal handler. With the handler is reached,
218 # disable SIGSEGV, ensuring that further signals stop the
219 # inferior. Stops a SIGSEGV infinite loop when a broke system
220 # keeps re-executing the faulting instruction.
222 gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
223 gdb_test "continue" "keeper.*" "${name}; continue to keeper"
224 gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
226 # Insert all the breakpoints. To avoid the need to step over
227 # these instructions, this is delayed until after the keeper has
228 # been reached. Always set a breakpoint at the signal trampoline
230 set args [concat $args "*[at_segv]"]
231 for {set i 0} {$i < [llength $args]} {incr i} {
232 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
233 "${name}; set breakpoint $i of [llength $args]"
236 # Let the handler return, it should "appear to hit" the breakpoint
237 # inserted at the faulting instruction. Note that the breakpoint
238 # instruction wasn't executed, rather the inferior was SIGTRAPed
239 # with the PC at the breakpoint.
240 gdb_test "continue" "Breakpoint.*pc(\r\n| *)=> [at_segv] .*" \
241 "${name}; continue to breakpoint at fault"
243 # Now single step the faulted instrction at that breakpoint.
245 "Program received signal ${signame}.*pc(\r\n| *)=> [at_segv] .*" \
246 "${name}; stepi fault"
248 # Clear any breakpoints
249 for {set i 0} {$i < [llength $args]} {incr i} {
250 gdb_test "clear [lindex $args $i]" "Deleted .*" \
251 "${name}; clear breakpoint $i of [llength $args]"
258 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
259 # breakpoints around the faulting address. In all cases the inferior
260 # should single-step out of the signal trampoline halting (but not
261 # executing) the fault instruction.
264 stepi_out "stepi bp before segv" "*[before_segv]"
265 stepi_out "stepi bp at segv" "*[at_segv]"
266 stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
269 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
270 # breakpoints around the faulting address. In all cases the inferior
271 # should exit the signal trampoline halting at the breakpoint that
272 # replaced the fault instruction.
274 cont_out "cont bp after segv" "*[before_segv]"
275 cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"