1 # This testcase is part of GDB, the GNU debugger.
3 # Copyright 2004, 2005, 2007 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 2 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, write to the Free Software
17 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 # Check that GDB can and only executes single instructions when
20 # stepping through a sequence of breakpoints interleaved by a signal
23 # This test is known to tickle the following problems: kernel letting
24 # the inferior execute both the system call, and the instruction
25 # following, when single-stepping a system call; kernel failing to
26 # propogate the single-step state when single-stepping the sigreturn
27 # system call, instead resuming the inferior at full speed; GDB
28 # doesn't know how to software single-step across a sigreturn
29 # instruction. Since the kernel problems can be "fixed" using
30 # software single-step this is KFAILed rather than XFAILed.
32 if [target_info exists gdb,nosignals] {
33 verbose "Skipping sigbpt.exp because of nosignals."
45 set srcfile ${testfile}.c
46 set binfile ${objdir}/${subdir}/${testfile}
47 if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
54 gdb_reinitialize_dir $srcdir/$subdir
58 # Run to `main' where we begin our tests.
61 if ![runto_main] then {
65 # If we can examine what's at memory address 0, it is possible that we
66 # could also execute it. This could probably make us run away,
67 # executing random code, which could have all sorts of ill effects,
68 # especially on targets without an MMU. Don't run the tests in that
73 -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
74 -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
75 -re ".*$gdb_prompt $" {
76 untested "Memory at address 0 is possibly executable"
81 gdb_test "break keeper"
83 # Run to bowler, and then single step until there's a SIGSEGV. Record
84 # the address of each single-step instruction (up to and including the
85 # instruction that causes the SIGSEGV) in bowler_addrs, and the address
86 # of the actual SIGSEGV in segv_addr.
88 set bowler_addrs bowler
90 gdb_test {display/i $pc}
91 gdb_test "advance *bowler" "bowler.*" "advance to the bowler"
92 set test "stepping to SIGSEGV"
93 gdb_test_multiple "stepi" "$test" {
94 -re "Program received signal SIGSEGV.*pc *(0x\[0-9a-f\]*).*$gdb_prompt $" {
95 set segv_addr $expect_out(1,string)
98 -re " .*pc *(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
99 set bowler_addrs [concat $expect_out(1,string) $bowler_addrs]
105 # Now record the address of the instruction following the faulting
106 # instruction in bowler_addrs.
108 set test "get insn after fault"
109 gdb_test_multiple {x/2i $pc} "$test" {
110 -re "(0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
111 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
116 # Procedures for returning the address of the instruction before, at
117 # and after, the faulting instruction.
119 proc before_segv { } {
121 return [lindex $bowler_addrs 2]
126 return [lindex $bowler_addrs 1]
129 proc after_segv { } {
131 return [lindex $bowler_addrs 0]
134 # Check that the address table and SIGSEGV correspond.
136 set test "Verify that SIGSEGV occurs at the last STEPI insn"
137 if {[string compare $segv_addr [at_segv]] == 0} {
140 fail "$test ($segv_addr [at_segv])"
143 # Check that the inferior is correctly single stepped all the way back
144 # to a faulting instruction.
146 proc stepi_out { name args } {
149 # Set SIGSEGV to pass+nostop and then run the inferior all the way
150 # through to the signal handler. With the handler is reached,
151 # disable SIGSEGV, ensuring that further signals stop the
152 # inferior. Stops a SIGSEGV infinite loop when a broke system
153 # keeps re-executing the faulting instruction.
155 gdb_test "handle SIGSEGV nostop print pass" "" "${name}; pass SIGSEGV"
156 gdb_test "continue" "keeper.*" "${name}; continue to keeper"
157 gdb_test "handle SIGSEGV stop print nopass" "" "${name}; nopass SIGSEGV"
159 # Insert all the breakpoints. To avoid the need to step over
160 # these instructions, this is delayed until after the keeper has
162 for {set i 0} {$i < [llength $args]} {incr i} {
163 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
164 "${name}; set breakpoint $i of [llength $args]"
167 # Single step our way out of the keeper, through the signal
168 # trampoline, and back to the instruction that faulted.
169 set test "${name}; stepi out of handler"
170 gdb_test_multiple "stepi" "$test" {
171 -re "Could not insert single-step breakpoint.*$gdb_prompt $" {
172 setup_kfail "sparc*-*-openbsd*" gdb/1736
173 fail "$test (could not insert single-step breakpoint)"
175 -re "keeper.*$gdb_prompt $" {
179 -re "signal handler.*$gdb_prompt $" {
183 -re "Program received signal SIGSEGV.*$gdb_prompt $" {
184 kfail gdb/1702 "$test (executed fault insn)"
186 -re "Breakpoint.*pc *[at_segv] .*bowler.*$gdb_prompt $" {
187 pass "$test (at breakpoint)"
189 -re "Breakpoint.*pc *[after_segv] .*bowler.*$gdb_prompt $" {
190 kfail gdb/1702 "$test (executed breakpoint)"
192 -re "pc *[at_segv] .*bowler.*$gdb_prompt $" {
195 -re "pc *[after_segv] .*bowler.*$gdb_prompt $" {
196 kfail gdb/1702 "$test (skipped fault insn)"
198 -re "pc *0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {
199 kfail gdb/1702 "$test (corrupt pc)"
203 # Clear any breakpoints
204 for {set i 0} {$i < [llength $args]} {incr i} {
205 gdb_test "clear [lindex $args $i]" "Deleted .*" \
206 "${name}; clear breakpoint $i of [llength $args]"
210 # Let a signal handler exit, returning to a breakpoint instruction
211 # inserted at the original fault instruction. Check that the
212 # breakpoint is hit, and that single stepping off that breakpoint
213 # executes the underlying fault instruction causing a SIGSEGV.
215 proc cont_out { name args } {
218 # Set SIGSEGV to pass+nostop and then run the inferior all the way
219 # through to the signal handler. With the handler is reached,
220 # disable SIGSEGV, ensuring that further signals stop the
221 # inferior. Stops a SIGSEGV infinite loop when a broke system
222 # keeps re-executing the faulting instruction.
224 gdb_test "handle SIGSEGV nostop print pass" "" "${name}; pass SIGSEGV"
225 gdb_test "continue" "keeper.*" "${name}; continue to keeper"
226 gdb_test "handle SIGSEGV stop print nopass" "" "${name}; nopass SIGSEGV"
228 # Insert all the breakpoints. To avoid the need to step over
229 # these instructions, this is delayed until after the keeper has
230 # been reached. Always set a breakpoint at the signal trampoline
232 set args [concat $args "*[at_segv]"]
233 for {set i 0} {$i < [llength $args]} {incr i} {
234 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
235 "${name}; set breakpoint $i of [llength $args]"
238 # Let the handler return, it should "appear to hit" the breakpoint
239 # inserted at the faulting instruction. Note that the breakpoint
240 # instruction wasn't executed, rather the inferior was SIGTRAPed
241 # with the PC at the breakpoint.
242 gdb_test "continue" "Breakpoint.*pc *[at_segv] .*" \
243 "${name}; continue to breakpoint at fault"
245 # Now single step the faulted instrction at that breakpoint.
247 "Program received signal SIGSEGV.*pc *[at_segv] .*" \
248 "${name}; stepi fault"
250 # Clear any breakpoints
251 for {set i 0} {$i < [llength $args]} {incr i} {
252 gdb_test "clear [lindex $args $i]" "Deleted .*" \
253 "${name}; clear breakpoint $i of [llength $args]"
260 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
261 # breakpoints around the faulting address. In all cases the inferior
262 # should single-step out of the signal trampoline halting (but not
263 # executing) the fault instruction.
266 stepi_out "stepi bp before segv" "*[before_segv]"
267 stepi_out "stepi bp at segv" "*[at_segv]"
268 stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
271 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
272 # breakpoints around the faulting address. In all cases the inferior
273 # should exit the signal trampoline halting at the breakpoint that
274 # replaced the fault instruction.
276 cont_out "cont bp after segv" "*[before_segv]"
277 cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"