Re: [RFA] Reverse-step/next and shared libraries (with testsuite)

[Hui Zhu <teawater at gmail dot com>]

I try this patch in SLED 10.  Everything is OK.

Thanks,
Hui

On Mon, Jun 22, 2009 at 07:10, Michael Snyder<msnyder@vmware.com> wrote:
> OK, this is a bit of a rewrite for the infrun code that
> handles reverse stepping into/over shared library functions
> and trampolines. ?I believe we now correctly handle various
> combinations of ...
> ?* reverse-step, reverse-next
> ?* trampolines, solib-dynsym-resolver
> ?* resolved and unresolved symbols
> ?* debuggable (user) and undebuggable (eg. libc) functions
>
> This also includes the first testsuite test case for reverse
> debugging. ?If this one's accepted, I've got more queued up.
>
> Hui, this patch will replace your patch
> http://sourceware.org/ml/gdb-patches/2009-03/msg00005.html,
> so I'll appreciate your review.
>
> Marc, this patch should fix all of your solib step/next bugs.
>
> No regressions on linux-i686.
>
>
> 2009-06-21 ?Michael Snyder ?<msnyder@vmware.com>
>
> ? ? ? ?* infrun.c (handle_inferior_event): Improve handling of
> ? ? ? ?reverse-stepping into and over shared library functions.
>
> 2009-06-21 ?Michael Snyder ?<msnyder@vmware.com>
>
> ? ? ? ?* gdb.base/solib-reverse.exp: New file.
> ? ? ? ?* gdb.base/solib-reverse.c: New file.
>
> Index: infrun.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/infrun.c,v
> retrieving revision 1.392
> diff -u -p -r1.392 infrun.c
> --- infrun.c ? ?18 Jun 2009 23:55:57 -0000 ? ? ?1.392
> +++ infrun.c ? ?21 Jun 2009 22:50:22 -0000
> @@ -3639,7 +3639,7 @@ infrun: not switching back to stepped th
> ? if (stop_pc >= ecs->event_thread->step_range_start
> ? ? ? && stop_pc < ecs->event_thread->step_range_end
> ? ? ? && (execution_direction != EXEC_REVERSE
> - ? ? ? ? || frame_id_eq (get_frame_id (get_current_frame ()),
> + ? ? ? ? || frame_id_eq (get_frame_id (frame),
> ? ? ? ? ? ? ? ? ? ? ? ? ?ecs->event_thread->step_frame_id)))
> ? ? {
> ? ? ? if (debug_infrun)
> @@ -3667,10 +3667,19 @@ infrun: not switching back to stepped th
> ? /* We stepped out of the stepping range. ?*/
>
> ? /* If we are stepping at the source level and entered the runtime
> - ? ? loader dynamic symbol resolution code, we keep on single stepping
> - ? ? until we exit the run time loader code and reach the callee's
> - ? ? address. ?*/
> - ?if (ecs->event_thread->step_over_calls == STEP_OVER_UNDEBUGGABLE
> + ? ? loader dynamic symbol resolution code...
> +
> + ? ? EXEC_FORWARD: we keep on single stepping until we exit the run
> + ? ? time loader code and reach the callee's address.
> +
> + ? ? EXEC_REVERSE: we've already executed the callee (backward), and
> + ? ? the runtime loader code is handled just like any other
> + ? ? undebuggable function call. ?Now we need only keep stepping
> + ? ? backward through the trampoline code, and that's handled further
> + ? ? down, so there is nothing for us to do here. ?*/
> +
> + ?if (execution_direction != EXEC_REVERSE
> + ? ? ?&& ecs->event_thread->step_over_calls == STEP_OVER_UNDEBUGGABLE
> ? ? ? && in_solib_dynsym_resolve_code (stop_pc))
> ? ? {
> ? ? ? CORE_ADDR pc_after_resolver =
> @@ -3740,12 +3749,29 @@ infrun: not switching back to stepped th
> ? ? ? ? ?/* Also, maybe we just did a "nexti" inside a prolog, so we
> ? ? ? ? ? ? thought it was a subroutine call but it was not. ?Stop as
> ? ? ? ? ? ? well. ?FENN */
> + ? ? ? ? /* And this works the same backward as frontward. ?MVS */
> ? ? ? ? ?ecs->event_thread->stop_step = 1;
> ? ? ? ? ?print_stop_reason (END_STEPPING_RANGE, 0);
> ? ? ? ? ?stop_stepping (ecs);
> ? ? ? ? ?return;
> ? ? ? ?}
>
> + ? ? ?/* Reverse stepping through solib trampolines. ?*/
> +
> + ? ? ?if (execution_direction == EXEC_REVERSE
> + ? ? ? ? && (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
> + ? ? ? ? ? ? || (ecs->stop_func_start == 0
> + ? ? ? ? ? ? ? ? && in_solib_dynsym_resolve_code (stop_pc))))
> + ? ? ? {
> + ? ? ? ? /* Any solib trampoline code can be handled in reverse
> + ? ? ? ? ? ?by simply continuing to single-step. ?We have already
> + ? ? ? ? ? ?executed the solib function (backwards), and a few
> + ? ? ? ? ? ?steps will take us back through the trampoline to the
> + ? ? ? ? ? ?caller. ?*/
> + ? ? ? ? keep_going (ecs);
> + ? ? ? ? return;
> + ? ? ? }
> +
> ? ? ? if (ecs->event_thread->step_over_calls == STEP_OVER_ALL)
> ? ? ? ?{
> ? ? ? ? ?/* We're doing a "next".
> @@ -3763,35 +3789,10 @@ infrun: not switching back to stepped th
> ? ? ? ? ? ?{
> ? ? ? ? ? ? ?struct symtab_and_line sr_sal;
>
> - ? ? ? ? ? ? if (ecs->stop_func_start == 0
> - ? ? ? ? ? ? ? ? && in_solib_dynsym_resolve_code (stop_pc))
> - ? ? ? ? ? ? ? {
> - ? ? ? ? ? ? ? ? /* Stepped into runtime loader dynamic symbol
> - ? ? ? ? ? ? ? ? ? ?resolution code. ?Since we're in reverse,
> - ? ? ? ? ? ? ? ? ? ?we have already backed up through the runtime
> - ? ? ? ? ? ? ? ? ? ?loader and the dynamic function. ?This is just
> - ? ? ? ? ? ? ? ? ? ?the trampoline (jump table).
> -
> - ? ? ? ? ? ? ? ? ? ?Just keep stepping, we'll soon be home.
> - ? ? ? ? ? ? ? ? */
> - ? ? ? ? ? ? ? ? keep_going (ecs);
> - ? ? ? ? ? ? ? ? return;
> - ? ? ? ? ? ? ? }
> - ? ? ? ? ? ? if (gdbarch_skip_trampoline_code(current_gdbarch,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?get_current_frame (),
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?stop_pc))
> - ? ? ? ? ? ? ? {
> - ? ? ? ? ? ? ? ? /* We are in a function call trampoline.
> - ? ? ? ? ? ? ? ? ? ?Keep stepping backward to get to the caller. ?*/
> - ? ? ? ? ? ? ? ? ecs->event_thread->stepping_over_breakpoint = 1;
> - ? ? ? ? ? ? ? }
> - ? ? ? ? ? ? else
> - ? ? ? ? ? ? ? {
> - ? ? ? ? ? ? ? ? /* Normal function call return (static or dynamic). ?*/
> - ? ? ? ? ? ? ? ? init_sal (&sr_sal);
> - ? ? ? ? ? ? ? ? sr_sal.pc = ecs->stop_func_start;
> - ? ? ? ? ? ? ? ? insert_step_resume_breakpoint_at_sal (sr_sal,
> null_frame_id);
> - ? ? ? ? ? ? ? }
> + ? ? ? ? ? ? /* Normal function call return (static or dynamic). ?*/
> + ? ? ? ? ? ? init_sal (&sr_sal);
> + ? ? ? ? ? ? sr_sal.pc = ecs->stop_func_start;
> + ? ? ? ? ? ? insert_step_resume_breakpoint_at_sal (sr_sal, null_frame_id);
> ? ? ? ? ? ?}
> ? ? ? ? ?else
> ? ? ? ? ? ?insert_step_resume_breakpoint_at_caller (frame);
> Index: testsuite/gdb.base/solib-reverse.c
> ===================================================================
> RCS file: testsuite/gdb.base/solib-reverse.c
> diff -N testsuite/gdb.base/solib-reverse.c
> --- /dev/null ? 1 Jan 1970 00:00:00 -0000
> +++ testsuite/gdb.base/solib-reverse.c ?21 Jun 2009 22:54:01 -0000
> @@ -0,0 +1,26 @@
> +/* Test reverse debugging of shared libraries. ?*/
> +
> +#include <stdio.h>
> +
> +/* Shared library function */
> +extern int shr2(int);
> +
> +int main ()
> +{
> + ?char* cptr = "String 1";
> + ?int b[2] = {5,8};
> +
> + ?b[0] = shr2(12); ? ? ? ? ? ? /* begin part two */
> + ?b[1] = shr2(17); ? ? ? ? ? ? /* middle part two */
> +
> + ?b[0] = 6; ? b[1] = 9; ? ? ? ? ? ? ? ?/* generic statement, end part two
> */
> + ?printf ("message 1\n"); ? ? ?/* printf one */
> + ?printf ("message 2\n"); ? ? ?/* printf two */
> + ?printf ("message 3\n"); ? ? ?/* printf three */
> + ?sleep (0); ? ? ? ? ? ? ? ? ? /* sleep one */
> + ?sleep (0); ? ? ? ? ? ? ? ? ? /* sleep two */
> + ?sleep (0); ? ? ? ? ? ? ? ? ? /* sleep three */
> +
> + ?return 0; ? ? ? ? ? ? ? ? ? ?/* end part one */
> +}
> +
> Index: testsuite/gdb.base/solib-reverse.exp
> ===================================================================
> RCS file: testsuite/gdb.base/solib-reverse.exp
> diff -N testsuite/gdb.base/solib-reverse.exp
> --- /dev/null ? 1 Jan 1970 00:00:00 -0000
> +++ testsuite/gdb.base/solib-reverse.exp ? ? ? ?21 Jun 2009 22:54:01 -0000
> @@ -0,0 +1,127 @@
> +# Copyright 2009
> +# 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 was written by Michael Snyder (msnyder@vmware.com).
> +
> +#
> +# Test reverse debugging with shared libraries.
> +#
> +
> +if ![target_info exists gdb,can_reverse] {
> + ? ?return
> +}
> +
> +set testfile "solib-reverse"
> +set srcfile ?${testfile}.c
> +set libfile ?"shr2"
> +set libsrc ? ${libfile}.c
> +set library ?${objdir}/${subdir}/${libfile}.sl
> +set binfile ?${objdir}/${subdir}/${testfile}
> +
> +if [get_compiler_info ${binfile}] {
> + ? ?return -1
> +}
> +
> +if { [gdb_compile_shlib ${srcdir}/${subdir}/${libsrc} ${library} "debug"]
> != "" } {
> + ? ?untested "Could not compile shared library."
> + ? ?return -1
> +}
> +
> +set exec_opts [list debug shlib=${library}]
> +
> +if { [gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile} executable
> $exec_opts] != "" } {
> + ? ?untested "Could not compile $binfile."
> + ? ?return -1
> +}
> +
> +# Start with a fresh gdb.
> +
> +gdb_exit
> +gdb_start
> +gdb_reinitialize_dir $srcdir/$subdir
> +gdb_load ${binfile}
> +
> +
> +runto main
> +
> +if [target_info exists gdb,use_precord] {
> + ? ?# Activate process record/replay
> + ? ?gdb_test "record" "" "Turn on process record"
> + ? ?# FIXME: command ought to acknowledge, so we can test if it succeeded.
> +}
> +
> +#
> +# Test reverse-step over undebuggable solib functions.
> +#
> +
> +# Run forward past some solib function calls.
> +
> +set end_part_one [gdb_get_line_number " end part one" "$srcfile"]
> +set end_part_two [gdb_get_line_number " end part two" "$srcfile"]
> +gdb_test "until $end_part_one" " end part one.*" "run until end part one"
> +
> +gdb_test "reverse-step" " sleep three .*" "reverse-step third sleep"
> +gdb_test "reverse-step" " sleep two .*" ? "reverse-step second sleep"
> +gdb_test "reverse-step" " sleep one .*" ? \
> + ? ? ? ? ? ? ? ? ? "reverse-step first sleep, dynsym resolve"
> +
> +gdb_test "reverse-step" " printf three .*" "reverse-step third printf"
> +gdb_test "reverse-step" " printf two .*" ? "reverse-step second printf"
> +gdb_test "reverse-step" " printf one .*" ? \
> + ? ? ? ? ? ? ? ? ? "reverse-step first printf, dynsym resolve"
> +gdb_test "reverse-step" " generic statement.*" "reverse-step generic"
> +
> +
> +#
> +# Test reverse-next over undebuggable solib functions.
> +#
> +
> +# Run forward again...
> +
> +gdb_test "until $end_part_one" " end part one.*" "forward to end part one"
> +
> +gdb_test "reverse-next" " sleep three .*" "reverse-next third sleep"
> +gdb_test "reverse-next" " sleep two .*" ? "reverse-next second sleep"
> +gdb_test "reverse-next" " sleep one .*" ? \
> + ? ? ? ? ? ? ? ? ? "reverse-next first sleep, dynsym resolve"
> +
> +gdb_test "reverse-next" " printf three .*" "reverse-next third printf"
> +gdb_test "reverse-next" " printf two .*" ? "reverse-next second printf"
> +gdb_test "reverse-next" " printf one .*" ? \
> + ? ? ? ? ? ? ? ? ? "reverse-next first printf, dynsym resolve"
> +gdb_test "reverse-next" " generic statement.*" "reverse-next generic"
> +
> +
> +#
> +# Test reverse-step into debuggable solib function
> +#
> +
> +gdb_test "reverse-step" "${libsrc}.*" "reverse-step into solib function
> one"
> +gdb_test "reverse-step" "return 2.x.*" "reverse-step within solib function
> one"
> +gdb_test "reverse-step" " middle part two.*" "reverse-step back to main
> one"
> +
> +gdb_test "reverse-step" "${libsrc}.*" "reverse-step into solib function
> two"
> +gdb_test "reverse-step" "return 2.x.*" "reverse-step within solib function
> two"
> +gdb_test "reverse-step" " begin part two.*" "reverse-step back to main two"
> +
> +#
> +# Test reverse-next over debuggable solib function
> +#
> +
> +gdb_test "until $end_part_two" " end part two.*" "run until end part two"
> +
> +gdb_test "reverse-next" " middle part two.*" "reverse-next over solib
> function one"
> +gdb_test "reverse-next" " begin part two.*" "reverse-next over solib
> function two"
>
>