binutils-gdb/gdb/testsuite/gdb.reverse/maint-print-instruction.exp
Bruno Larsen e24d337e21 gdb: add 'maintenance print record-instruction' command
While chasing some reverse debugging bugs, I found myself wondering what
was recorded by GDB to undo and redo a certain instruction. This commit
implements a simple way of printing that information.

If there isn't enough history to print the desired instruction (such as
when the user hasn't started recording yet or when they request 2
instructions back but only 1 was recorded), GDB warns the user like so:

(gdb) maint print record-instruction
Not enough recorded history

If there is enough, GDB prints the instruction like so:

(gdb) maint print record-instruction
4 bytes of memory at address 0x00007fffffffd5dc changed from: 01 00 00 00
Register eflags changed: [ IF ]
Register rip changed: (void (*)()) 0x401115 <main+15>

Approved-by: Eli Zaretskii <eliz@gnu.org>
Reviewed-by: Alexandra Hajkova <ahajkova@redhat.com>
Reviewed-by: Lancelot Six <lsix@lancelotsix.com>
Approved-by: Tom Tromey <tom@tromey.com>
2023-01-04 11:21:57 +01:00

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# Copyright 2022-2023 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This file is part of the GDB testsuite. It tests the functionality of
# the maintenance print record-instruction command, but does not check the
# syntax, only if the command finds or fails to find recorded history.
# This is done by putting the inferior in mulpitle states with and without
# history to be printed, then checking if GDB is able to print an
# instruction or not.
# To identify if GDB has printed an instruction, we can see if some
# change is printed, since any instruction must have at least a change
# to the PC.
if ![supports_reverse] {
return
}
standard_testfile
if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
return -1
}
proc test_print { has_history level test_name } {
gdb_test_multiple "maint print record-instruction $level" $test_name {
-re -wrap ".*Not enough recorded history.*" {
gdb_assert !$has_history $test_name
}
-re -wrap ".*changed.*" {
gdb_assert $has_history $test_name
}
}
}
if { ![runto_main] } {
return 0
}
#confirm that GDB doesn't go crazy if recording isn't enabled
test_print false "" "print before starting to record"
if ![supports_process_record] {
# No point in testing the rest if we can't record anything
return
}
gdb_test_no_output "record" "turn on process record"
test_print false "" "print before any instruction"
gdb_test "stepi 3" ".*" "collecting history"
test_print true "" "print current after executing a bit"
test_print true "-1" "print previous after executing a bit"
test_print false "1" "print following after executing a bit"
gdb_test "reverse-stepi" ".*" "moving back"
test_print true "" "print current after reversing"
test_print true "-1" "print previous after reversing"
test_print true "1" "print following after reversing"
test_print false "-10" "trying to print too far back"
test_print false "10" "trying to print too far forward"