gdb/testsuite/gdb.base/bp-permanent.exp

   1 # Copyright (C) 2014-2023 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 # This file is part of the gdb testsuite.
  17
  18 # Test stepping over permanent breakpoints.
  19
  20 standard_testfile
  21
  22 set options { debug }
  23 if { ![target_info exists gdb,nosignals] } {
  24     lappend options "additional_flags=-DSIGNALS"
  25 }
  26
  27 if {[build_executable "failed to prepare" $testfile $srcfile $options]} {
  28     return -1
  29 }
  30
  31 set line_bp [gdb_get_line_number "write permanent bp"]
  32
  33 # The test proper.  ALWAYS_INSERTED indicates whether testing in
  34 # "breakpoint always-inserted" mode.  If SW_WATCHPOINT is true, set a
  35 # software watchpoint, which forces constantly single-stepping, and
  36 # exercises stepping the permanent breakpoint while delivering a
  37 # signal at the same time.
  38
  39 proc test {always_inserted sw_watchpoint} {
  40     global line_bp
  41     global hex decimal
  42     global gdb_prompt
  43     global srcfile binfile
  44
  45     clean_restart $binfile
  46
  47     if {![runto_main]} {
  48         return -1
  49     }
  50
  51     gdb_test "set breakpoint always-inserted $always_inserted"
  52
  53     if {$sw_watchpoint} {
  54         # Watching a convenience variable forces a software
  55         # watchpoint.
  56         gdb_test "watch \$dummy_convenience" "Watchpoint .*"
  57     }
  58
  59     set address_bp ""
  60     set address_after_bp ""
  61
  62     with_test_prefix "setup" {
  63
  64         # Set a breakpoint where we'll manually plant a permanent
  65         # breakpoint.
  66         set test "set probe breakpoint"
  67         gdb_test_multiple "break $line_bp" $test {
  68             -re "Breakpoint .* at ($hex).*$gdb_prompt $" {
  69                 set address_bp $expect_out(1,string)
  70                 pass $test
  71             }
  72         }
  73         if {$address_bp == ""} {
  74             return
  75         }
  76
  77         # Get the size of the instruction where the breakpoint will
  78         # manually inserted.
  79         set test "get size of instruction"
  80         gdb_test_multiple "x/2i $address_bp" $test {
  81             -re ".*$hex <test\\+$decimal>:\[^\r\n\]+\r\n\[ \]+($hex).*\.\r\n$gdb_prompt $" {
  82                 set address_after_bp $expect_out(1,string)
  83                 pass $test
  84             }
  85         }
  86         if {$address_after_bp == ""} {
  87             return
  88         }
  89
  90         # Write address range where the breakpoint is inserted to the
  91         # corresponding variables in the inferior.
  92         gdb_test "p /x addr_bp = $address_bp" " = $address_bp" \
  93             "write addr_bp"
  94         gdb_test "p /x addr_after_bp = $address_after_bp" " = $address_after_bp" \
  95             "write addr_after_bp"
  96
  97         # Run the "setup" function in the inferior.  This memcpy's the
  98         # breakpoint instruction to a buffer in the inferior.
  99         gdb_test "next" "test_basics \\(\\).*" "next over setup"
 100
 101         delete_breakpoints
 102
 103         # We now have the breakpoint instruction stored in 'buffer'.  Poke it
 104         # to memory manually.
 105         set count [expr $address_after_bp - $address_bp]
 106         for {set i 0} {$i < $count} {incr i} {
 107             set test "p /x addr_bp\[$i\] = buffer\[$i\]"
 108             gdb_test_multiple $test $test {
 109                 -re "Cannot access memory at address $hex.*$gdb_prompt $" {
 110                     # Some targets (QEMU for one) will disallow writes to the
 111                     # .text section under certain circumstances.  It is no use
 112                     # continuing with the test at this point.  Just return.
 113                     unsupported "cannot modify memory"
 114                     return
 115                 }
 116                 -re " = .*$gdb_prompt $" {
 117                     pass $test
 118                 }
 119             }
 120         }
 121     }
 122
 123     with_test_prefix "basics" {
 124         # Run to the permanent breakpoint, just to make sure we've inserted it
 125         # correctly.
 126         # If the target fails to stop, the remainder of the test will not work
 127         # so just return.  This can happen on some simulator targets where
 128         # the running program doesn't see breakpoints that are visible to
 129         # the execution engine, or where writes to the .text section are
 130         # quietly ignored.
 131         set test "permanent breakpoint causes random signal"
 132         gdb_test_multiple "continue" $test {
 133             -re "exited normally.*$gdb_prompt $" {
 134                 unsupported "failed to stop at permanent breakpoint"
 135                 return
 136             }
 137             -re "Program received signal SIGTRAP.*$gdb_prompt $" {
 138                 pass $test
 139             }
 140         }
 141
 142         # Now set a breakpoint on top, thus creating a permanent breakpoint.
 143         gdb_breakpoint "$line_bp"
 144
 145         # Depending on whether this is a decr_pc_after_break arch, the PC will
 146         # be either pointing at the permanent breakpoint address, or just
 147         # after.  Set the GDB breakpoint on top, and continue, twice.  At
 148         # least once, GDB will need to step-over the permanent breakpoint.
 149
 150         gdb_test "continue" "Breakpoint .*" "stop at permanent breakpoint"
 151
 152         gdb_test "p \$prev_counter = counter" " = $decimal"
 153
 154         gdb_test "continue" "Breakpoint .*" "stop at permanent breakpoint twice"
 155
 156         # Check that indeed the continue made progress, instead of re-trapping
 157         # without advancing.
 158         gdb_test "p counter - \$prev_counter" " = 1"
 159
 160         gdb_test "info breakpoints" \
 161             "breakpoint.*keep.*y.*$hex.*in test at .*$srcfile:$line_bp.*already hit 2 times.*" \
 162             "info breakpoints show enabled breakpoint"
 163
 164         gdb_test "disable \$bpnum"
 165
 166         gdb_test "commands\nset \$commands_ran = 1\nend" "" \
 167             "set breakpoint commands"
 168
 169         gdb_test "info breakpoints" \
 170             "breakpoint.*keep.*n.*$hex.*in test at .*$srcfile:$line_bp.*already hit 2 times.*" \
 171             "info breakpoints shows disabled breakpoint"
 172
 173         # Run to the permanent breakpoint again.  This time, since it's
 174         # disabled, it should act as if we hadn't created it in the first
 175         # place.  IOW, we should get a random signal, and, the breakpoint's
 176         # command should not run.
 177         gdb_test "continue" "Program received signal SIGTRAP.*" \
 178             "disabled permanent breakpoint doesn't explain stop"
 179
 180         gdb_test "info breakpoints" \
 181             "breakpoint.*keep.*n.*$hex.*in test at .*$srcfile:$line_bp.*already hit 2 times.*" \
 182             "info breakpoints still shows same number of hits"
 183
 184         gdb_test "print \$commands_ran" " = void" \
 185             "breakpoint commands didn't run"
 186
 187         # Reenable the breakpoint, and check that it gets hit and accounted
 188         # for this time.
 189         gdb_test "enable \$bpnum" "" "reenable breakpoint"
 190
 191         gdb_test "continue" "Breakpoint .*" \
 192             "stop at permanent breakpoint thrice"
 193
 194         gdb_test "info breakpoints" \
 195             "breakpoint.*keep.*y.*$hex.*in test at .*$srcfile:$line_bp.*already hit 3 times.*" \
 196             "info breakpoints shows one more hit"
 197
 198         gdb_test "print \$commands_ran" " = 1" "breakpoint commands ran"
 199
 200         # Check that stepi advances only past the permanent breakpoint, and
 201         # not a single instruction more.
 202         gdb_test "stepi" "after permanent bp .*" \
 203             "single-step past permanent breakpoint"
 204     }
 205
 206     with_test_prefix "next trips on permanent bp" {
 207         delete_breakpoints
 208
 209         gdb_breakpoint "test_next"
 210         gdb_continue_to_breakpoint "test_next"
 211
 212         gdb_breakpoint "$line_bp"
 213         gdb_test "condition \$bpnum 0"
 214
 215         gdb_test "next" "after next .*"
 216     }
 217
 218     if ![target_info exists gdb,nosignals] {
 219
 220         with_test_prefix "continue trips on nested permanent bp" {
 221             delete_breakpoints
 222
 223             gdb_breakpoint "test_signal_nested"
 224             gdb_continue_to_breakpoint "test_signal_nested"
 225
 226             gdb_breakpoint "$line_bp"
 227             gdb_continue_to_breakpoint "permanent bp"
 228             gdb_test "condition \$bpnum 0"
 229
 230             # Let SIGALRM trigger.
 231             sleep 2
 232
 233             # We're now stopped at a permanent breakpoint, with a
 234             # signal pending.
 235             gdb_breakpoint "test_signal_nested_done"
 236             gdb_continue_to_breakpoint "test_signal_nested_done"
 237
 238             # Ensure that the handler did run.  There's one call to
 239             # test in the mainline code, and another in the signal
 240             # handler.
 241             gdb_test "p counter" " = 2"
 242         }
 243
 244         if [can_single_step_to_signal_handler] {
 245
 246             with_test_prefix "stepi signal with handler" {
 247                 delete_breakpoints
 248
 249                 gdb_breakpoint "test_signal_with_handler"
 250                 gdb_continue_to_breakpoint "test_signal_with_handler"
 251
 252                 gdb_breakpoint "$line_bp"
 253
 254                 gdb_test "continue" "Breakpoint .*" "stop at permanent breakpoint"
 255
 256                 gdb_test "queue-signal SIGUSR1"
 257
 258                 set test "single-step to handler"
 259                 gdb_test_multiple "stepi" $test {
 260                     -re "Program received signal SIGTRAP.*$gdb_prompt $" {
 261                         fail $test
 262                     }
 263                     -re "signal handler called.*$gdb_prompt $" {
 264                         # After PowerPC Linux kernel commit:
 265                         #
 266                         #   commit: 0138ba5783ae0dcc799ad401a1e8ac8333790df9
 267                         #   powerpc/64/signal: Balance return predictor
 268                         #   stack in signal trampoline.
 269                         #
 270                         # The kernel places an additional brctl instruction
 271                         # in the vdso to call the user handler.
 272                         #
 273                         # And then this commit:
 274                         #
 275                         #   commit 24321ac668e452a4942598533d267805f291fdc9
 276                         #   powerpc/64/signal: Fix regression in
 277                         #   __kernel_sigtramp_rt64() semantics
 278                         #
 279                         # updates the semantics of __kernel_sigtramp_rt64().
 280                         # It added a new symbol to serve as a jump target from
 281                         # the kernel to the trampoline.
 282                         #
 283                         # The net result of these changes is that gdb stops
 284                         # at  __kernel_start_sigtramp_rt64.  Need to do one
 285                         # more stepi to reach the expected location in the user
 286                         # signal handler.
 287                         gdb_test "p \$pc" "__kernel_start_sigtramp_rt64.*" \
 288                             "in kernel code"
 289                         gdb_test "stepi" "handler .*" $test
 290                     }
 291                     -re "handler .*$gdb_prompt $" {
 292                         pass $test
 293                     }
 294                 }
 295
 296                 # Check that the mainline PC points at the permanent
 297                 # breakpoint.
 298                 gdb_test "up 2" "test .*" "up to mainline code"
 299
 300                 gdb_test "p /x \$pc" " = $address_bp" \
 301                     "mainline pc points at permanent breakpoint"
 302
 303                 gdb_test "continue" "Breakpoint .*" \
 304                     "stop at permanent breakpoint, out of handler"
 305             }
 306
 307             with_test_prefix "stepi signal with no handler" {
 308                 gdb_breakpoint "test_signal_no_handler"
 309                 gdb_continue_to_breakpoint "test_signal_no_handler"
 310
 311                 gdb_test "continue" "Breakpoint .*" "stop at permanent breakpoint"
 312
 313                 gdb_test "queue-signal SIGUSR1"
 314
 315                 gdb_test "stepi" "after permanent bp .*" \
 316                     "single-step past permanent breakpoint"
 317             }
 318         }
 319     }
 320 }
 321
 322 foreach always_inserted {off on} {
 323     foreach sw_watchpoint {0 1} {
 324         with_test_prefix "always_inserted=$always_inserted, sw_watchpoint=$sw_watchpoint" {
 325             test $always_inserted $sw_watchpoint
 326         }
 327     }
 328 }