Re: [reverse/record] adjust_pc_after_break in reverse execution mode?

Michael Snyder
2008-10-24T00:45:10Z

Thank you!
I'll put it on the branch for now...

Does it make sense to include a forward version of this test,
for normal (non-reverse/non-replay) targets?

Pedro Alves wrote:
>> I've done so a bit this morning, and came to a similar
>> conclusion, although I noticed Hui's change to set stop_pc in
>> TARGET_WAITKIND_NO_HISTORY, also also required. I was wanting
>> to find time to play a little bit more, but since you're on to it...
>
> BTW, I noticed that, while reviewing Hui's latest patch
> (which was missing setting the waitkind to TARGET_WAITKIND_STOPPED,
> hence could never work :-) ). While doing so, I dejagnufied the
> nop testcase into the attached. Maybe you'll find it useful.
>
> --
> Pedro Alves
>
>
> ------------------------------------------------------------------------
>
> 2008-10-24 Pedro Alves <pedro@codesourcery.com>
>
> * gdb.base/decr-pc-rev.c, gdb.base/decr-pc-rev.exp: New test.
>
> ---
> gdb/testsuite/gdb.base/decr-pc-rev.c | 26 +++++++++
> gdb/testsuite/gdb.base/decr-pc-rev.exp | 86 +++++++++++++++++++++++++++++++++
> 2 files changed, 112 insertions(+)
>
> Index: src/gdb/testsuite/gdb.base/decr-pc-rev.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ src/gdb/testsuite/gdb.base/decr-pc-rev.c 2008-10-23 15:21:02.000000000 +0100
> @@ -0,0 +1,26 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> + Copyright 2008 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/>. */
> +
> +int
> +main ()
> +{
> + asm ("nop"); /* first insn */
> + asm ("nop"); /* second insn */
> + asm ("nop"); /* third insn */
> + asm ("nop"); /* fourth insn */
> + return 0;
> +}
> Index: src/gdb/testsuite/gdb.base/decr-pc-rev.exp
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ src/gdb/testsuite/gdb.base/decr-pc-rev.exp 2008-10-23 15:21:02.000000000 +0100
> @@ -0,0 +1,86 @@
> +# Copyright 2008 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/>.
> +
> +if $tracelevel then {
> + strace $tracelevel
> +}
> +
> +# Test PC adjustment behaviour on decr_pc_after_break archs in reverse
> +# and replay modes, in the presence of breakpoints at consecutive
> +# instruction addresses.
> +
> +set testfile "decr-pc-rev"
> +set srcfile ${testfile}.c
> +set binfile ${objdir}/${subdir}/${testfile}
> +
> +if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug nowarnings}] != "" } {
> + untested consecutive.exp
> + return -1
> +}
> +
> +if [get_compiler_info ${binfile}] {
> + return -1
> +}
> +
> +gdb_exit
> +gdb_start
> +gdb_reinitialize_dir $srcdir/$subdir
> +gdb_load ${binfile}
> +
> +if [target_info exists gdb_stub] {
> + gdb_step_for_stub;
> +}
> +
> +if ![runto_main] then {
> + perror "couldn't run to breakpoint"
> + continue
> +}
> +
> +# These breakpoint should be placed at consecutive instructions, such
> +# that the address difference between them is equal to
> +# decr_pc_after_break on this arquitecture.
> +
> +set bp_location1 [gdb_get_line_number "first insn"]
> +set bp_location2 [gdb_get_line_number "second insn"]
> +
> +# Enable recording.
> +
> +gdb_test "record" "" "enable record target"
> +
> +# Step through the breakpoints creating some history.
> +
> +gdb_test "next" ".*second insn.*" "next (1)"
> +gdb_test "next" ".*third insn.*" "next (2)"
> +gdb_test "next" ".*fourth insn.*" "next (3)"
> +gdb_test "next" ".*return 0.*" "next (4)"
> +
> +# Set consecutive breakpoints.
> +
> +gdb_test "break $bp_location1" \
> + ".*Breakpoint .*$srcfile, line $bp_location1\\." \
> + "first breakpoint line number"
> +
> +gdb_test "break $bp_location2" \
> + "Breakpoint.*at.* file .*$srcfile, line $bp_location2\\." \
> + "second breakpoint line number"
> +
> +# Test that reverse-continue doesn't mess with decr_pc_after_break
> +
> +gdb_test "rc" ".*second insn.*" "reverse continue to breakpoint"
> +gdb_test "rn" ".*first insn.*" "reverse next to begining of times"
> +
> +# Test that replay behaves as normal play.
> +gdb_test "next" ".*second insn.*" "next (1) in replay"
> +gdb_test "next" ".*third insn.*" "next (2) in replay"