1 # This testcase is part of GDB, the GNU debugger.
3 # Copyright 2004 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.
40 set srcfile ${testfile}.c
41 set binfile ${objdir}/${subdir}/${testfile}
42 if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
43 gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
48 gdb_reinitialize_dir $srcdir/$subdir
52 # Run to `main' where we begin our tests.
55 if ![runto_main] then {
59 # If we can examine what's at memory address 0, it is possible that we
60 # could also execute it. This could probably make us run away,
61 # executing random code, which could have all sorts of ill effects,
62 # especially on targets without an MMU. Don't run the tests in that
67 -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
68 -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
69 -re ".*$gdb_prompt $" {
70 untested "Memory at address 0 is possibly executable"
75 gdb_test "break keeper"
77 # Run to bowler, and then single step until there's a SIGSEGV. Record
78 # the address of each single-step instruction (up to and including the
79 # instruction that causes the SIGSEGV) in bowler_addrs, and the address
80 # of the actual SIGSEGV in segv_addr.
82 set bowler_addrs bowler
83 gdb_test {display/i $pc}
84 gdb_test "advance *bowler" "bowler.*" "advance to the bowler"
85 set test "stepping to SIGSEGV"
86 gdb_test_multiple "stepi" "$test" {
87 -re "Program received signal SIGSEGV.*pc *(0x\[0-9a-f\]*).*$gdb_prompt $" {
88 set segv_addr $expect_out(1,string)
91 -re " .*pc *(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
92 set bowler_addrs [concat $expect_out(1,string) $bowler_addrs]
98 # Now record the address of the instruction following the faulting
99 # instruction in bowler_addrs.
101 set test "get insn after fault"
102 gdb_test_multiple {x/2i $pc} "$test" {
103 -re "(0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
104 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
109 # Procedures for returning the address of the instruction before, at
110 # and after, the faulting instruction.
112 proc before_segv { } {
114 return [lindex $bowler_addrs 2]
119 return [lindex $bowler_addrs 1]
122 proc after_segv { } {
124 return [lindex $bowler_addrs 0]
127 # Check that the address table and SIGSEGV correspond.
129 set test "Verify that SIGSEGV occurs at the last STEPI insn"
130 if {[string compare $segv_addr [at_segv]] == 0} {
133 fail "$test ($segv_addr [at_segv])"
136 # Check that the inferior is correctly single stepped all the way back
137 # to a faulting instruction.
139 proc stepi_out { name args } {
142 # Set SIGSEGV to pass+nostop and then run the inferior all the way
143 # through to the signal handler. With the handler is reached,
144 # disable SIGSEGV, ensuring that further signals stop the
145 # inferior. Stops a SIGSEGV infinite loop when a broke system
146 # keeps re-executing the faulting instruction.
148 gdb_test "handle SIGSEGV nostop print pass" "" "pass SIGSEGV; $name"
149 gdb_test "continue" "keeper.*" "continue to keeper; $name"
150 gdb_test "handle SIGSEGV stop print nopass" "" "nopass SIGSEGV; $name"
152 # Insert all the breakpoints. To avoid the need to step over
153 # these instructions, this is delayed until after the keeper has
155 for {set i 0} {$i < [llength $args]} {incr i} {
156 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
157 "set breakpoint $i of [llength $args]; $name"
160 # Single step our way out of the keeper, through the signal
161 # trampoline, and back to the instruction that faulted.
162 set test "stepi out of handler; $name"
163 gdb_test_multiple "stepi" "$test" {
164 -re "keeper.*$gdb_prompt $" {
168 -re "signal handler.*$gdb_prompt $" {
172 -re "Program received signal SIGSEGV.*$gdb_prompt $" {
173 kfail gdb/1702 "$test (executed fault insn)"
175 -re "Breakpoint.*pc *[at_segv] .*bowler.*$gdb_prompt $" {
176 pass "$test (at breakpoint)"
178 -re "Breakpoint.*pc *[after_segv] .*bowler.*$gdb_prompt $" {
179 kfail gdb/1702 "$test (executed breakpoint)"
181 -re "pc *[at_segv] .*bowler.*$gdb_prompt $" {
184 -re "pc *[after_segv] .*bowler.*$gdb_prompt $" {
185 kfail gdb/1702 "$test (skipped fault insn)"
189 # Clear any breakpoints
190 for {set i 0} {$i < [llength $args]} {incr i} {
191 gdb_test "clear [lindex $args $i]" "Deleted .*" \
192 "clear breakpoint $i of [llength $args]; $name"
196 # Let a signal handler exit, returning to a breakpoint instruction
197 # inserted at the original fault instruction. Check that the
198 # breakpoint is hit, and that single stepping off that breakpoint
199 # executes the underlying fault instruction causing a SIGSEGV.
201 proc cont_out { name args } {
204 # Set SIGSEGV to pass+nostop and then run the inferior all the way
205 # through to the signal handler. With the handler is reached,
206 # disable SIGSEGV, ensuring that further signals stop the
207 # inferior. Stops a SIGSEGV infinite loop when a broke system
208 # keeps re-executing the faulting instruction.
210 gdb_test "handle SIGSEGV nostop print pass" "" "pass SIGSEGV; $name"
211 gdb_test "continue" "keeper.*" "continue to keeper; $name"
212 gdb_test "handle SIGSEGV stop print nopass" "" "nopass SIGSEGV; $name"
214 # Insert all the breakpoints. To avoid the need to step over
215 # these instructions, this is delayed until after the keeper has
216 # been reached. Always set a breakpoint at the signal trampoline
218 set args [concat $args "*[at_segv]"]
219 for {set i 0} {$i < [llength $args]} {incr i} {
220 gdb_test "break [lindex $args $i]" "Breakpoint.*" \
221 "set breakpoint $i of [llength $args]; $name"
224 # Let the handler return, it should "appear to hit" the breakpoint
225 # inserted at the faulting instruction. Note that the breakpoint
226 # instruction wasn't executed, rather the inferior was SIGTRAPed
227 # with the PC at the breakpoint.
228 gdb_test "continue" "Breakpoint.*pc *[at_segv] .*" \
229 "continue to breakpoint at fault; $name"
231 # Now single step the faulted instrction at that breakpoint.
233 "Program received signal SIGSEGV.*pc *[at_segv] .*" \
236 # Clear any breakpoints
237 for {set i 0} {$i < [llength $args]} {incr i} {
238 gdb_test "clear [lindex $args $i]" "Deleted .*" \
239 "clear breakpoint $i of [llength $args]; $name"
246 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
247 # breakpoints around the faulting address. In all cases the inferior
248 # should single-step out of the signal trampoline halting (but not
249 # executing) the fault instruction.
252 stepi_out "stepi bp before segv" "*[before_segv]"
253 stepi_out "stepi bp at segv" "*[at_segv]"
254 stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
257 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
258 # breakpoints around the faulting address. In all cases the inferior
259 # should exit the signal trampoline halting at the breakpoint that
260 # replaced the fault instruction.
262 cont_out "cont bp after segv" "*[before_segv]"
263 cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"