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gdbserver-base.exp is used as the base for both native-gdbserver.exp and
native-extended-gdbserver.exp. (Despite its name, it should really be
considered as a "local-gdbserver-base", as it's not really appropriate to
implement a remote gdbserver board.)
Currently, the _download procedure is implemented as a no-op (it returns
the source file path). Because of the SONAME change, The fast
tracepoint tests now require the executable and the IPA
(libinproctrace.so) to be located in the same directory (see [1]). When
using the native-gdbserver board, because _download returns the original
file path, the executable does not end up in the same directory as the
library, and it fails to execute.
In more general terms, with the recent changes, the testsuite now
assumes that when it does
${board}_download <source path 1> <destination path 1>
${board}_download <source path 2> <destination path 2>
where the destination paths are relative (generally just the file name),
both files will end up in the same base directory. That assumption does
not hold for the current implementation in gdbserver-base.exp.
The proper fix would be to make native-gdbserver non-remote, so that
gdb_remote_download would not call DejaGnu's remote_download (see [2]).
We could then get rid of ${board}_download in gdbserver-base.exp.
However, that will likely take some time to complete. In the mean time,
in order to make the fast tracepoint tests pass, we can simply copy the
file to the standard output directory. Basically, it just mimics what
gdb_remote_download would do if the board wasn't flagged as remote.
Note that I missed these failures originally because I had a
libinproctrace.so in /usr/local/lib. So, even though libinproctrace.so
wasn't copied to the test output directory, it did find the one in
/usr/local/lib. It would be nice to find a way to protect against this,
as it could easily happen again...
Regtested with unix, native-gdbserver and native-extended-gdbserver, and
didn't see anything notable, except the ftrace tests now passing for
native-gdbserver.
[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=6e774b13c3b81ac2599812adf058796948ce7e95
[2] https://sourceware.org/ml/gdb-patches/2016-04/msg00112.html
gdb/testsuite/ChangeLog:
* boards/gdbserver-base.exp (${board}_download): Copy source file to
standard output directory.
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This patch fixes the following failure:
FAIL: gdb.trace/trace-condition.exp: ftrace: -(21 << 1) == -42: check 10
frames were collected.
This was due to aarch64_emit_sub using the wrong order in its operands, so the
operation would end up being 42 - 0 rather than 0 - 42.
This patch also fixes the order of aarch64_emit_add for clarity.
The test case for emit_sub is fixed so that the proper order of
the operands is needed for the test to pass.
Tested on aarch64-native-extended-gdbserver.
Note: trace-condition.exp was broken a bit so I had to modify it to run
the test. A fix is coming for that in another patch.
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_emit_add): Switch x1 and x0.
(aarch64_emit_sub): Likewise.
gdb/testsuite/ChangeLog:
* gdb.trace/trace-condition.exp (foreach): Fix emit_sub testcase.
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Reverse debugging against a remote target that does reverse debugging
itself (with the bs/bc packets) always trips on:
(gdb) target remote localhost:...
(gdb) reverse-stepi
../../gdb/target.c:602: internal-error: default_execution_direction: to_execution_direction must be implemented for reverse async
I missed adding a to_execution_direction method to remote.c in commit
3223143295b5 (Adds target_execution_direction to make record targets
support async mode), GDB 7.4 time. Later, GDB 7.8 switched to
target-async on by default, making the regression user-visible by
default too.
Fix is simply to add the missing to_execution_direction implementation
to target remote.
Tested by Andi Kleen against Simics.
gdb/ChangeLog:
2016-04-13 Pedro Alves <palves@redhat.com>
PR remote/19840
* remote.c (struct remote_state) <last_resume_exec_dir>: New
field.
(new_remote_state): Default last_resume_exec_dir to EXEC_FORWARD.
(remote_open_1): Reset last_resume_exec_dir to EXEC_FORWARD.
(remote_resume): Store the last execution direction.
(remote_execution_direction): New function.
(init_remote_ops): Install it as to_execution_direction target_ops
method.
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On systems with a newer version of GCC the gdb.btrace/instruction_history.exp
test fails to build like this:
Running .../gdb.btrace/instruction_history.exp ...
gdb compile failed, .../gdb.btrace/instruction_history.c:
In function 'main': .../gdb.btrace/instruction_history.c:24:3: warning:
implicit declaration of function 'loop' [-Wimplicit-function-declaration]
loop ();
^
Declare loop to fix it.
testsuite/
* gdb.btrace/instruction_history.c (loop): Add declaration.
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This obvious patch replaces "ond" wiht "cond" as the test prefix for
conditional tests.
gdb/testsuite/ChangeLog:
* gdb.trace/ftrace.exp (proc): Change test prefix from "ond" to "cond".
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Now that we don't ever throw GDB exceptions from signal handlers [1],
we can switch back to having TRY/CATCH implemented in terms of C++
try/catch instead of sigjmp/longjmp.
[1] - https://sourceware.org/ml/gdb-patches/2016-03/msg00351.html
Tested on x86_64 Fedora 23, native and gdbserver.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* common/common-exceptions.h (GDB_XCPT_TRY): Update comment.
[__cplusplus] (GDB_XCPT): Define as GDB_XCPT_TRY.
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Now that we don't ever throw GDB exceptions from signal handlers [1],
we can switch to have TRY/CATCH implemented in terms of plain
setjmp/longjmp instead of sigsetjmp/siglongjmp.
In https://sourceware.org/ml/gdb-patches/2015-02/msg00114.html, Yichun
Zhang mentions a 11%/14%+ speedup in his GDB python scripts with a
patch that did something similar to only a specific set of TRY/CATCH
calls.
[1] - https://sourceware.org/ml/gdb-patches/2016-03/msg00351.html
Tested on x86_64 Fedora 23, native and gdbserver.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <buf>: Now a
'jmp_buf' instead of SIGJMP_BUF.
(exceptions_state_mc_init): Change return type to 'jmp_buf'.
(throw_exception): Use longjmp instead of SIGLONGJMP.
* common/common-exceptions.h: Include <setjmp.h> instead of
"gdb_setjmp.h".
(exceptions_state_mc_init): Change return type to 'jmp_buf'.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY): Use setjmp instead of
SIGSETJMP.
* cp-support.c: Include "gdb_setjmp.h".
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No longer necessary.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (exception_rethrow): Remove
prepare_to_throw_exception call.
* common/common-exceptions.h (prepare_to_throw_exception): Delete
declaration.
* exceptions.c (prepare_to_throw_exception): Delete.
gdb/gdbserver/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* utils.c (prepare_to_throw_exception): Delete.
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This is no longer called anywhere.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* target.c (target_check_pending_interrupt): Delete.
* target.h (struct target_ops) <to_check_pending_interrupt>:
Remove method.
(target_check_pending_interrupt): Remove declaration.
* target-delegates.c: Regenerate.
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This finally gets rid of immediate_quit (and surrounding
infrustruture), as nothing sets it anymore.
gdb_call_async_signal_handler was only necessary in order to handle
immediate_quit. We can just call mark_async_signal_handler directly
on all hosts now.
In turn, we can clean up mingw-hdep.c's gdb_select a bit, as
sigint_event / sigint_handler is no longer needed.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* defs.h: Update comments on SIGINT handling.
(immediate_quit): Delete declaration.
* event-loop.c (call_async_signal_handler): Delete.
* event-loop.h (call_async_signal_handler): Delete declaration.
(mark_async_signal_handler): Update comments.
(gdb_call_async_signal_handler): Delete declaration.
* event-top.c (handle_sigint): Call mark_async_signal_handler
instead of gdb_call_async_signal_handler.
* exceptions.c (prepare_to_throw_exception): Remove reference to
immediate_quit.
(exception_fprintf): Remove comments about immediate_quit.
* mingw-hdep.c (sigint_event, sigint_handler): Delete.
(gdb_select): Don't wait on sigint_event.
(gdb_call_async_signal_handler): Delete.
(_initialize_mingw_hdep): Delete.
* posix-hdep.c (gdb_call_async_signal_handler): Delete.
* utils.c (immediate_quit): Delete.
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remote.c is the last user of immediate_quit. It's relied on to
immediately break the initial remote connection sync up, if the user
does Ctrl-C, assuming that was because the target isn't responding.
At that stage, since the connection isn't synced yet, disconnecting is
the only safe thing to do. This commit reworks that, to not rely on
throwing from the SIGINT signal handler.
So, this commit:
- Introduces the concept of a "quit handler". This is used to
override what does the QUIT macro do when the quit flag is set.
- Makes the "struct serial" reachar / write code call QUIT in the
partial read/write loops, so the current quit handler is invoked
whenever a serial->read_prim / serial->write_prim returns EINTR.
- Makes the "struct serial" reachar / write code call
interruptible_select instead of gdb_select, so that QUITs are
detected in a race-free manner.
- Stops remote.c from setting immediate_quit during the initial
connection.
- Instead, we install a custom quit handler whenever we're calling
into the serial code. This custom quit handler knows to immediately
throw a quit when we're in the initial connection setup, and
otherwise defer handling the quit/Ctrl-C request to later, when
we're safely out of a packet command/response sequence. This also
is what is now responsible for handling "double Ctrl-C because
target connection is stuck/wedged."
- remote.c no longer installs a specialized SIGINT handlers, and
instead re-uses the quit flag. Since we want to rely on the QUIT
macro, the SIGINT handler must also set the quit. And the easiest
is just to not install custom SIGINT handler in remote.c. Let the
standard SIGINT handler do its job of setting the quit flag.
Centralizing SIGINT handlers seems like a good thing to me, anyway.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* defs.h (quit_handler_ftype, quit_handler)
(make_cleanup_override_quit_handler, default_quit_handler): New.
(QUIT): Adjust comments.
* event-top.c (default_quit_handler): New function.
(quit_handler): New global.
(struct quit_handler_cleanup_data): New.
(restore_quit_handler, restore_quit_handler_dtor)
(make_cleanup_override_quit_handler): New.
(async_request_quit): Call QUIT.
* remote.c (struct remote_state) <got_ctrlc_during_io>: New field.
(async_sigint_remote_twice_token, async_sigint_remote_token):
Delete.
(remote_close): Update comments.
(remote_start_remote): Don't set immediate_quit. Set starting_up
earlier.
(remote_serial_quit_handler, remote_unpush_and_throw): New
functions.
(remote_open_1): Clear got_ctrlc_during_io. Set
remote_async_terminal_ours_p unconditionally.
(async_initialize_sigint_signal_handler)
(async_handle_remote_sigint, async_handle_remote_sigint_twice)
(remote_check_pending_interrupt, async_remote_interrupt)
(async_remote_interrupt_twice)
(async_cleanup_sigint_signal_handler, ofunc)
(sync_remote_interrupt, sync_remote_interrupt_twice): Delete.
(remote_terminal_inferior, remote_terminal_ours): Remove async
checks.
(remote_wait_as): Don't install a SIGINT handler in sync mode.
(readchar, remote_serial_write): Override the quit handler with
remote_serial_quit_handler.
(getpkt_or_notif_sane_1): Don't call QUIT.
(initialize_remote_ops): Don't install
remote_check_pending_interrupt.
(_initialize_remote): Don't create async_sigint_remote_token and
async_sigint_remote_twice_token.
* ser-base.c (ser_base_wait_for): Call QUIT and use
interruptible_select.
(ser_base_write): Call QUIT.
* ser-go32.c (dos_readchar, dos_write): Call QUIT.
* ser-unix.c (wait_for): Don't use VTIME. Always take the
gdb_select path, but call QUIT and interruptible_select.
* utils.c (maybe_quit): Call the current quit handler. Don't call
target_check_pending_interrupt.
(defaulted_query, prompt_for_continue): Override the quit handler
with the default quit handler.
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Nothing actually uses this global.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* tui/tui-hooks.c (tui_target_has_run): Delete.
(tui_about_to_proceed): Delete.
(tui_about_to_proceed_observer): Delete.
(tui_install_hooks, tui_remove_hooks): Don't install/remove an
about_to_proceed observer.
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The MI code only does output, so leave raw/cooked mode alone, as well
as the SIGINT handler. Restore terminal settings after output, while
at it. Also, a couple events missed calling target_terminal_ours
before output, even.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* mi/mi-interp.c (mi_new_thread): Put
target_terminal_ours_for_output in effect while outputting.
(mi_thread_exit): Use target_terminal_ours_for_output instead of
target_terminal_ours.
(mi_record_changed, mi_inferior_added, mi_inferior_appeared)
(mi_inferior_exit, mi_inferior_removed, mi_traceframe_changed)
(mi_tsv_created, mi_tsv_deleted, mi_tsv_modified)
(mi_breakpoint_created, mi_breakpoint_deleted)
(mi_breakpoint_modified, mi_solib_loaded, mi_solib_unloaded)
(mi_command_param_changed, mi_memory_changed)
(report_initial_inferior): Use target_terminal_ours_for_output
instead of target_terminal_ours. Restore terminal settings.
* mi/mi-main.c (mi_execute_command): Use
target_terminal_ours_for_output instead of target_terminal_ours.
Restore terminal settings.
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Any time a caller calls query & friends / prompt_for_continue without
ensuring that gdb owns the terminal for input is a bug. So do that in
defaulted_query / prompt_for_continue directly instead.
An example of a case where we currently miss calling
target_terminal_ours is internal_error. Ever since defaulted_query
was made to use gdb_readline_callback, there's no way to answer the
internal error query if the internal error happens while the target is
has the terminal:
(gdb) c
Continuing.
.../src/gdb/linux-nat.c:1676: internal-error: linux_nat_resume: Assertion `dummy_counter < 10' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) _
Entering 'y' or 'n' does not work, GDB does not respond.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
PR gdb/19828
* gnu-nat.c (inf_validate_task_sc): Don't call
target_terminal_ours / target_terminal_inferior around query.
* i386-tdep.c (i386_record_lea_modrm, i386_process_record): Don't
call target_terminal_ours / target_terminal_inferior around
yquery.
* linux-record.c (record_linux_system_call): Don't call
target_terminal_ours / target_terminal_inferior around yquery.
* nto-procfs.c (interrupt_query): Don't call target_terminal_ours
/ target_terminal_inferior around query.
* record-full.c (record_full_check_insn_num): Remove
'set_terminal' parameter. Don't call target_terminal_ours /
target_terminal_inferior around query.
(record_full_message, record_full_registers_change)
(record_full_xfer_partial): Adjust.
* remote.c (interrupt_query): Don't call target_terminal_ours /
target_terminal_inferior around query.
* utils.c (defaulted_query): Install cleanup to restore target
terminal. Put target_terminal_ours_for_output in effect while
defaulted producing, and target_terminal_ours in in effect while
handling input.
(prompt_for_continue): Install cleanup to restore target terminal.
Put target_terminal_ours in in effect while handling input.
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Some of the error paths in these functions leak.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* utils.c (defaulted_query, prompt_for_continue): Free temporary
strings with cleanups, instead of xfree.
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We're only doing output here, so leave raw/cooked mode alone, as well
as the SIGINT handler.
And restore terminal settings, while at it.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* utils.c (vwarning, internal_vproblem): Use
make_cleanup_restore_target_terminal and
target_terminal_ours_for_output.
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We're only doing output here, so leave raw/cooked mode alone, as well
as the SIGINT handler.
No need to restore terminal settings, we'll set inferior modes on the
following resume.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* infcmd.c (post_create_inferior, prepare_one_step): Use
target_terminal_ours_for_output instead of target_terminal_ours.
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We're only doing output here, so leave raw/cooked mode alone, as well
as the SIGINT handler.
Restore terminal settings after output, while at it.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* exceptions.c (print_flush): Use target_terminal_ours_for_output
instead of target_terminal_ours, and restore target terminal with
a cleanup.
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We're only doing output here, so leave raw/cooked mode alone, as well
as the SIGINT handler.
Restore terminal settings after output, while at it.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* cp-support.c (gdb_demangle): Use target_terminal_ours_for_output
instead of target_terminal_ours, and restore target terminal with
a cleanup.
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A couple wrong things here
- We should not use target_terminal_ours when all we want is output.
We should use target_terminal_ours_for_output instead, which
preserves raw/cooked terminal modes, and SIGINT forwarding.
- Most importantly, relying on stderr output immediately preceding
the error/exception print isn't correct. The exception could be
caught and handled, for example; MI frontends won't display the
stderr part in an error dialog box. Etc.
This commit introduces a type_as_string helper that allows building a
full error string including type info.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* ada-lang.c (type_as_string, type_as_string_and_cleanup): New
functions.
(ada_lookup_struct_elt_type): Use type_as_string_and_cleanup.
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- If serial->write_prim returns EINTR, ser_bas_write returns it to the
caller. This just looks wrong to me -- part of the output may have
already been sent, and there's no way for the caller to know that,
and thus no way for a caller to handle a partial write correctly.
- While ser-unix.c:ser_unix_read_prim retries on EINTR,
ser-tcp.c:net_read_prim does not.
This commit moves EINTR handling to the ser_base_write and
ser_base_readchar level, so all serial backends (at least those that
use it) end up handling EINTR consistently.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* ser-base.c (fd_event): Retry read_prim on EINTR.
(do_ser_base_readchar): Retry read_prim on EINTR.
(ser_base_write): Retry write_prim on EINTR.
* ser-unix.c (ser_unix_read_prim): Don't retry on EINTR here.
(ser_unix_write_prim): Remove comment.
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If the user presses Ctrl-C immediately before target_terminal_inferior
is called and the target is resumed, instead of after, the Ctrl-C ends
up pending in the quit flag until the target next stops.
remote.c has this bit to handle this:
if (!target_is_async_p ())
{
ofunc = signal (SIGINT, sync_remote_interrupt);
/* If the user hit C-c before this packet, or between packets,
pretend that it was hit right here. */
if (check_quit_flag ())
sync_remote_interrupt (SIGINT);
}
But that's only reachable if async is off, while async is on by
default nowadays. It's also obviously not reacheable on native
targets.
This patch generalizes that to all targets.
We can't remove that remote.c bit yet, until we get rid of the sync
SIGINT handler though. That'll be done later in the series.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* remote.c (remote_pass_ctrlc): New function.
(init_remote_ops): Install it.
* target.c (target_terminal_inferior): Pass pending Ctrl-C to the
target.
(target_pass_ctrlc, default_target_pass_ctrlc): New functions.
* target.h (struct target_ops) <to_pass_ctrlc>: New method.
(target_pass_ctrlc, default_target_pass_ctrlc): New declarations.
* target-delegates.c: Regenerate.
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In non-stop mode, "interrupt" results in a "stop with no signal",
while in all-stop mode, it results in a remote interrupt request /
stop with SIGINT. This is currently implemented in both the Linux and
remote target backends. Move it to the core code instead, making
target_interrupt specifically always about "Interrupting as if with
Ctrl-C", just like it is documented.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* infcmd.c (interrupt_target_1): Call target_stop is in non-stop
mode.
* linux-nat.c (linux_nat_interrupt): Delete.
(linux_nat_add_target): Don't install linux_nat_interrupt.
* remote.c (remote_interrupt_ns): Change return type to void.
Throw error if interrupting the target is not supported.
(remote_interrupt): Don't call the remote_stop_ns/remote_stop_as.
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Nothing calls this anymore.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* defs.h (clear_quit_flag): Remove declaration.
* extension-priv.h (struct extension_language_ops)
<clear_quit_flag>: Remove field and update comments.
* extension.c (clear_quit_flag): Delete.
* guile/guile.c (guile_extension_ops): Adjust.
* python/python.c (python_extension_ops): Adjust.
(gdbpy_clear_quit_flag): Delete.
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This call seems pointless. For instance, a SIGINT handler is only
installed later on. And if wasn't, I can't see why we'd want to lose
a Ctrl-C request.
Getting rid of this allows getting rid of clear_quit_flag.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* main.c (captured_main): Don't clear the quit flag.
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I think this is reminiscent of the time when a longjmp would always
jump to the top level. Nowaways code that throw exceptions other than
a quit, which may even be caught and handled without reaching the top
level. Certainly such exceptions shouldn't clear an interrupt
request...
(We also need to get rid of prepare_to_throw_exception in order to be
able to just do "throw ex;" in C++.)
One could argue that we should clear the quit flag when we throw a
quit from the SIGINT handler, when immediate_quit is in effect, to
handle a race, here:
immediate_quit++;
QUIT;
... that's the usual pattern code must use when enabling
immediate_quit. The QUIT is there to catch the case of Ctrl-C having
already been pressed before immediate_quit was enabled. However, this
can happen:
immediate_quit++;
<< Ctrl-C pressed here too.
QUIT;
And in that case, if the quit flag was already set, it'll stay set
even after throwing a quit from the SIGINT handler. The end result is
a double quit. But OTOH, the user did press Ctrl-C two times. Since
I'm getting rid of immediate_quit, I'm not bothering with this.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* exceptions.c (prepare_to_throw_exception): Don't clear the quit
flag.
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This just looks totally wrong to me, for completetly discarding a
user-requested Ctrl-C. I can't think of why we'd want do this here.
Actually, I digged the history, and found out that this has been here
since at least 7b4ac7e1ed2c (gdb-2.4, the initial revision, 1988), at
a time were we had a top level setjmp/longjmp, long before that got
wrapped in throw_exception and friends, and this code was in an
explicit loop, with the quit_flag cleared on every iteration, before
executing a command...
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* event-top.c (command_handler): Don't call clear_quit_flag.
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Obviously not necessary since check_quit_flag clears the flag as side
effect.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* remote-sim.c (gdb_os_poll_quit): Don't call clear_quit_flag.
* remote.c (remote_wait_as): Don't call clear_quit_flag.
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Now that we have an abstract for wakeable events, use it instead of a
(heavier) serial pipe.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* python/python.c: Include "ser-event.h".
(gdbpy_event_fds): Delete.
(gdbpy_serial_event): New.
(gdbpy_run_events): Change prototype. Use serial_event_clear
instead of serial_readchar.
(gdbpy_post_event): Use serial_event_set instead of serial_write.
(gdbpy_initialize_events): Use make_serial_event instead of
serial_pipe.
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We have places where we call a blocking gdb_select expecting that a
Ctrl-C will unblock it. However, if the Ctrl-C is pressed just before
gdb_select, the SIGINT handler runs before gdb_select, and thus
gdb_select won't return.
For example gdb_readline_no_editing:
QUIT;
/* Wait until at least one byte of data is available. Control-C
can interrupt gdb_select, but not fgetc. */
FD_ZERO (&readfds);
FD_SET (fd, &readfds);
if (gdb_select (fd + 1, &readfds, NULL, NULL, NULL) == -1)
and stdio_file_read:
/* For the benefit of Windows, call gdb_select before reading from
the file. Wait until at least one byte of data is available.
Control-C can interrupt gdb_select, but not read. */
{
fd_set readfds;
FD_ZERO (&readfds);
FD_SET (stdio->fd, &readfds);
if (gdb_select (stdio->fd + 1, &readfds, NULL, NULL, NULL) == -1)
return -1;
}
return read (stdio->fd, buf, length_buf);
This is a race classically fixed with either the self-pipe trick, or
by blocking SIGINT and then using pselect instead of select.
Blocking SIGINT most of the time would mean that check_quit_flag (and
thus QUIT) would need to do a syscall every time it is called, which
sounds best avoided, since QUIT is called in many loops. Thus we take
the self-pipe trick route (wrapped in a serial event).
Instead of having all places that need this manually add an extra file
descriptor to the set of gdb_select's watched file descriptors, we
introduce a wrapper, interruptible_select, that does that.
The Windows version of gdb_select actually does not suffer from this,
because mingw-hdep.c:gdb_call_async_signal_handler sets a Windows
event that gdb_select always waits on. So this patch can be seen as
generalization of that technique. We can't remove that extra event
from mingw-hdep.c until we get rid of immediate_quit though.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* defs.h: Extend QUIT-related comments to mention
interruptible_select.
(quit_serial_event_set, quit_serial_event_clear): Declare.
* event-top.c: Include "ser-event.h" and "gdb_select.h".
(quit_serial_event): New global.
(async_init_signals): Make quit_serial_event.
(quit_serial_event_set, quit_serial_event_clear)
(quit_serial_event_fd, interruptible_select): New functions.
* extension.c (set_quit_flag): Set the quit serial event.
(check_quit_flag): Clear the quit serial event.
* gdb_select.h (interruptible_select): New declaration.
* guile/scm-ports.c (ioscm_input_waiting): Use
interruptible_select instead of gdb_select.
* top.c (gdb_readline_no_editing): Likewise.
* ui-file.c (stdio_file_read): Likewise.
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|
GDB's core signal handling suffers from a classical signal handler /
mainline code race:
int
gdb_do_one_event (void)
{
...
/* First let's see if there are any asynchronous signal handlers
that are ready. These would be the result of invoking any of the
signal handlers. */
if (invoke_async_signal_handlers ())
return 1;
...
/* Block waiting for a new event. (...). */
if (gdb_wait_for_event (1) < 0)
return -1;
...
}
If a signal is delivered while gdb is blocked in the poll/select
inside gdb_wait_for_event, then the select/poll breaks with EINTR,
we'll loop back around and call invoke_async_signal_handlers.
However, if the signal handler runs between
invoke_async_signal_handlers and gdb_wait_for_event,
gdb_wait_for_event will block, until the next unrelated event...
The fix is to a struct serial_event, and register it in the set of
files that select/poll in gdb_wait_for_event waits on. The signal
handlers that defer work to invoke_async_signal_handlers call
mark_async_signal_handler, which is adjusted to also set the new
serial event in addition to setting a flag, and is thus now is
garanteed to immediately unblock the next gdb_select/poll call, up
until invoke_async_signal_handlers is called and the event is cleared.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* event-loop.c: Include "ser-event.h".
(async_signal_handlers_serial_event): New global.
(async_signals_handler, initialize_async_signal_handlers): New
functions.
(mark_async_signal_handler): Set
async_signal_handlers_serial_event.
(invoke_async_signal_handlers): Clear
async_signal_handlers_serial_event.
* event-top.c (async_init_signals): Call
initialize_async_signal_handlers.
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|
This patch adds a new "event" struct serial type, that is an
abstraction specifically for waking up blocking waits/selects,
implemented on top of a pipe on POSIX, and on top of a native Windows
event (CreateEvent, etc.) on Windows.
This will be used to plug signal handler / mainline code races.
For example, GDB can indefinitely delay handling a quit request if the
user presses Ctrl-C between the last QUIT call and the next (blocking)
gdb_select call in the event loop:
QUIT;
<<< press ctrl-c here and end up blocked in gdb_select
indefinitely.
gdb_select (...); // whoops, SIGINT was already handled, no EINTR.
A global alone (either the quit flag, or the "ready" flag of the async
signal handlers in the event loop) is not sufficient.
To plug races such as these on POSIX systems, we have to register some
waitable file descriptor in the set of files gdb_select waits on, and
write to it from the signal handler. This is classically a pipe, and
the pattern called the self-pipe trick. On Linux, it could be a more
efficient eventfd instead, but I'm sticking with a pipe for
simplifity, as we need it for portability anyway.
(Alternatively, we could use pselect/ppoll, and block signals until
the pselect. The latter is not a design I think GDB could use,
because we want the QUIT macro to be super cheap, as it is used in
loops. Plus, Windows.)
This is a "struct serial" because Windows's gdb_select relies on that.
Windows's gdb_select, our "select" replacement, knows how to wait on
all kinds of handles (regular files, pipes, sockets, console, etc.)
unlike the native Windows "select" function, which can only wait on
sockets. Each file descriptor for a "serial" type that is not
normally waitable with WaitForMultipleObjects must have a
corresponding struct serial instance. gdb_select then internally
looks up the struct serial instance that wraps each file descriptor,
and asks it for the corresponding Windows waitable handle.
We could use serial_pipe() to create a "struct serial"-wrapped pipe
that is usable everywhere, including Windows. That's what currently
python/python.c uses for cross-thread posting of events.
However, serial_write and serial_readchar are not designed to be
async-signal-safe on POSIX hosts. It's easier to bypass those when
setting/clearing the event source.
And writing and a serial pipe is a bit heavy weight on Windows.
gdb_select requires an extra thread to wait on the pipe and several
Windows events, when a single manual-reset Windows event, with no
extra thread is sufficient.
The intended usage is simply:
- Call make_serial_event to create a serial event object.
- From the signal handler call serial_event_set to set the event.
- From mainline code, have select/poll wait for serial_event_fd(), in
addition to whatever other files you're about to wait for.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add ser-event.c.
(HFILES_NO_SRCDIR): Add ser-event.h.
(COMMON_OBS): Add ser-event.o.
* ser-event.c, ser-event.h: New files.
* serial.c (new_serial): New function, factored out from
(serial_fdopen_ops): ... this.
(serial_open_ops_1): New function, factored out from
(serial_open): ... this.
(serial_open_ops): New function.
* serial.h (struct serial): Forware declare.
(serial_open_ops): New declaration.
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|
Not used by anything.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* serial.c (serial_open, serial_fdopen_ops, do_serial_close):
Remove references to name.
* serial.h (struct serial) <name>: Delete.
|
|
This code installs a custom signal handler that throws a quit
exception if remote_fio_no_longjmp is not set.
AFAICS, the only real reason for this might have been to unblock the
ui_file_read call, in remote_fileio_func_read. But ever since:
2009-11-13 Daniel Jacobowitz <dan@codesourcery.com>
* ui-file.c (stdio_file_read): Call gdb_select before read.
at:
https://sourceware.org/ml/gdb-patches/2009-11/msg00321.html
that call is interruptible.
This is not only useful for switching to native C++ exceptions, but
AFAICS, also fixes a potential mess up of the remote protocol
connection, since there are target_read_memory calls done while
remote_fio_no_longjmp is clear. If the user presses ctrl-c while GDB
is sending or receiving a packet, we'll stop the communication
immediately, at a point where it isn't safe.
gdbserver doesn't support the File I/O remote protocol extension so I
can't test this.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* remote-fileio.c (sigint_fileio_token, remote_fio_no_longjmp):
Delete.
(async_remote_fileio_interrupt): Delete.
(remote_fileio_ctrl_c_signal_handler): Don't call the async signal
handler. Instead just always set the ctrl_c flag.
(remote_fileio_reply): Clear remote_fio_ctrl_c_flag before
re-enabling the SIGINT handler.
(remote_fileio_func_open, remote_fileio_func_close)
(remote_fileio_func_read, remote_fileio_func_write)
(remote_fileio_func_lseek, remote_fileio_func_rename)
(remote_fileio_func_unlink, remote_fileio_func_stat)
(remote_fileio_func_fstat, remote_fileio_func_gettimeofday)
(remote_fileio_func_isatty, remote_fileio_func_system)
(remote_fileio_request): Remove references to
remote_fio_no_longjmp.
(initialize_remote_fileio): Don't create an async signal handler.
|
|
immediate_quit used to be necessary back when prompt_for_continue used
blocking fread, but nowadays it uses gdb_readline_wrapper, which is
implemented in terms of a nested event loop, which already knows how
to react to SIGINT:
#0 throw_it (reason=RETURN_QUIT, error=GDB_NO_ERROR, fmt=0x9d6d7e "Quit", ap=0x7fffffffcb88)
at .../src/gdb/common/common-exceptions.c:324
#1 0x00000000007bab5d in throw_vquit (fmt=0x9d6d7e "Quit", ap=0x7fffffffcb88) at .../src/gdb/common/common-exceptions.c:366
#2 0x00000000007bac9f in throw_quit (fmt=0x9d6d7e "Quit") at .../src/gdb/common/common-exceptions.c:385
#3 0x0000000000773a2d in quit () at .../src/gdb/utils.c:1039
#4 0x000000000065d81b in async_request_quit (arg=0x0) at .../src/gdb/event-top.c:893
#5 0x000000000065c27b in invoke_async_signal_handlers () at .../src/gdb/event-loop.c:949
#6 0x000000000065aeef in gdb_do_one_event () at .../src/gdb/event-loop.c:280
#7 0x0000000000770838 in gdb_readline_wrapper (prompt=0x7fffffffcd40 "---Type <return> to continue, or q <return> to quit---")
at .../src/gdb/top.c:873
The need for the QUIT in stdin_event_handler is then exposed by the
gdb.base/double-prompt-target-event-error.exp test, which has:
# We're now stopped in a pagination query while handling a
# target event (printing where the program stopped). Quitting
# the pagination should result in only one prompt being
# output.
send_gdb "\003p 1\n"
Without that change we'd get:
Continuing.
---Type <return> to continue, or q <return> to quit---PASS: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: continue to pagination
^CpQuit
(gdb) 1
Undefined command: "1". Try "help".
(gdb) PASS: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: first prompt
ERROR: Undefined command "".
UNRESOLVED: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: no double prompt
Vs:
Continuing.
---Type <return> to continue, or q <return> to quit---PASS: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: continue to pagination
^CQuit
(gdb) p 1
$1 = 1
(gdb) PASS: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: first prompt
PASS: gdb.base/double-prompt-target-event-error.exp: ctrlc target event: continue: no double prompt
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* event-top.c (stdin_event_handler): Call QUIT;
(prompt_for_continue): Don't run with immediate_quit set.
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|
As can be seen in the tui_redisplay_readline comment:
"The command could call prompt_for_continue and we must not restore
SingleKey so that the prompt and normal keymap are used."
immediate_quit is being used as proxy for "secondary prompt".
We have a better predicate nowadays, so use it.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* tui/tui-io.c (tui_redisplay_readline): Check
gdb_in_secondary_prompt_p instead of immediate_quit.
* tui/tui.c: Include top.h.
(tui_rl_startup_hook): Check gdb_in_secondary_prompt_p instead of
immediate_quit.
|
|
read_command_line is the only caller, and here we can assume we're
reading a regular file, not stdin.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* top.c (read_command_file): Inline command_loop here.
(command_loop): Delete.
|
|
AFAICS, immediate_quit was only needed here nowdays to be able to
interrupt gdb_readline_no_editing.
command_line_input can also take the gdb_readline_wrapper path, but
since that is built on top of the event loop (gdb_select / poll and
asynchronous signal handlers), it can be interrupted.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* top.c: Include "gdb_select.h".
(gdb_readline_no_editing): Wait for input with gdb_select instead
of blocking in fgetc.
(command_line_input): Don't set immediate_quit.
|
|
Required for Python 3
gdb/testsuite/ChangeLog:
* gdb.python/py-mi-events-gdb.py (signal_stop_handler): Add
parentheses to print.
(continue_handler): Likewise.
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|
There are a few small changes needed to make it work with a real remote
target.
- Remove the [is_remote target] check.
- Remove soname setting when building the lib, it's done by default now
anyway.
- In the compilation of the executable, pass the shared lib using the
shlib option, so that RPATH is set.
- Download the program to the target using gdb_remote_download, and
record the remote path. Remove loading of the program using
gdb_load_shlibs, which was not really appropriate anyway.
- Run the remote path through readlink (see comment in the code).
- Start gdbserver with the remote path.
Also, don't set executable and objfile variables, as they are unused.
Tested with native, native-gdbserver, native-extended-gdbserver, and a
remote gdbserver.
gdb/testsuite/ChangeLog:
* gdb.server/solib-list.exp: Remove is_remote check.
Pass shlib= to gdb_compile. Don't link shared library with
-soname. Call gdb_remote_download instead of gdb_load_shlibs.
Run binary filename through "readlink -f" on the target.
|
|
Commit 7817ea46148d (Improve gdb_remote_download, remove gdb_download)
caused:
FAIL: gdb.server/solib-list.exp: non-stop 0: target extended-remote (timeout)
FAIL: gdb.server/solib-list.exp: non-stop 0: continue (the program is no longer running)
FAIL: gdb.server/solib-list.exp: non-stop 0: p libvar
FAIL: gdb.server/solib-list.exp: non-stop 1: target extended-remote (timeout)
FAIL: gdb.server/solib-list.exp: non-stop 1: continue (the program is no longer running)
FAIL: gdb.server/solib-list.exp: non-stop 1: p libvar
gdb.log shows:
system interpreter is: /lib64/ld-linux-x86-64.so.2
...
spawn ../gdbserver/gdbserver --once :2347 /home/pedro/brno/pedro/gdb/mygit/build/gdb/testsuite/outputs/gdb.server/solib-list/ld-linux-x86-64.so.2 /home/pedro/brno/pedro/gdb/mygit/build/gdb/testsuite/outputs/gdb.server/solib-list/solib-list
Process /home/pedro/brno/pedro/gdb/mygit/build/gdb/testsuite/outputs/gdb.server/solib-list/ld-linux-x86-64.so.2 created; pid = 18637
Cannot exec /home/pedro/brno/pedro/gdb/mygit/build/gdb/testsuite/outputs/gdb.server/solib-list/ld-linux-x86-64.so.2: No such file or directory.
...
The test copied the interpreter to the outputs directory, however
ld-linux-x86-64.so.2 is a relative symlink that when copied points
nowhere:
$ ls -l testsuite/outputs/gdb.server/solib-list/
total 52
-rwxrwxr-x. 1 pedro pedro 13450 Apr 7 10:52 gdb.log
-rw-rw-r--. 1 pedro pedro 1512 Apr 7 10:52 gdb.sum
lrwxrwxrwx. 1 pedro pedro 10 Apr 7 11:39 ld-linux-x86-64.so.2 -> ld-2.22.so
-rwxrwxr-x. 1 pedro pedro 9464 Apr 7 11:39 solib-list
-rw-rw-r--. 1 pedro pedro 3472 Apr 7 11:39 solib-list-lib.c.o
-rw-rw-r--. 1 pedro pedro 2760 Apr 7 11:39 solib-list.o
-rwxrwxr-x. 1 pedro pedro 9232 Apr 7 11:39 solib-list.so
The copying comes from gdbserver_spawn ->
gdbserver_download_current_prog -> gdb_remote_download.
There's actually no need to download the interpreter to the target -
it's part of the target system/environment. So fix this by making the
test just not use gdb_load (and gdb_file_cmd as consequence) at all,
and instead pass the interpreter filename to gdbserver as an argument.
gdb/testsuite/ChangeLog:
2016-04-08 Pedro Alves <palves@redhat.com>
* gdb.server/solib-list.exp: Don't use gdb_load. Instead pass the
interpreter filename as argument to gdbserver_spawn.
* lib/gdbserver-support.exp (gdbserver_download_current_prog):
Return empty if $last_loaded_file does not exist.
|
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I did a quick pass over value.c and value.h and made some of the accessor methods'
pass-by-reference parameters const-correct. Besides the obvious benefits, this is
required if we want to use them on values that are already declared as const
(such as the parameters to lval_funcs).
There's probably a lot more stuff that can be made const, here and elsewhere.
gdb/ChangeLog:
2016-04-08 Martin Galvan <martin.galvan@tallertechnologies.com>
* value.c (value_next): Make pass-by-reference parameters const-correct.
(value_parent): Likewise.
(value_enclosing_type): Likewise.
(value_lazy): Likewise.
(value_stack): Likewise.
(value_embedded_offset): Likewise.
(value_pointed_to_offset): Likewise.
(value_raw_address): Likewise.
(deprecated_value_modifiable): Likewise.
(value_free_to_mark): Likewise.
(value_release_to_mark): Likewise.
(internalvar_name): Likewise.
(readjust_indirect_value_type): Likewise.
(value_initialized): Likewise.
* value.h (value_next): Likewise.
(value_parent): Likewise.
(value_enclosing_type): Likewise.
(value_lazy): Likewise.
(value_stack): Likewise.
(value_embedded_offset): Likewise.
(value_pointed_to_offset): Likewise.
(value_raw_address): Likewise.
(deprecated_value_modifiable): Likewise.
(value_free_to_mark): Likewise.
(value_release_to_mark): Likewise.
(internalvar_name): Likewise.
(readjust_indirect_value_type): Likewise.
(value_initialized): Likewise.
|
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on CentOS-7.2 I get
Running /home/jkratoch/redhat/gdb-test-reg/gdb/testsuite/gdb.base/jit.exp ...
FAIL: gdb.base/jit.exp: one_jit_test-1: continue to breakpoint: break here 2 (the program exited)
FAIL: gdb.base/jit.exp: one_jit_test-2: continue to breakpoint: break here 2 (the program exited)
FAIL: gdb.base/jit.exp: attach: one_jit_test-2: continue to breakpoint: break here 2 (the program exited)
FAIL: gdb.base/jit.exp: attach: one_jit_test-2: break here 2: set var wait_for_gdb = 1
FAIL: gdb.base/jit.exp: attach: one_jit_test-2: break here 2: detach (the program is no longer running)
FAIL: gdb.base/jit.exp: attach: one_jit_test-2: break here 2: attach
FAIL: gdb.base/jit.exp: attach: one_jit_test-2: break here 2: set var wait_for_gdb = 0
FAIL: gdb.base/jit.exp: PIE: one_jit_test-1: continue to breakpoint: break here 2 (the program exited)
Running /home/jkratoch/redhat/gdb-test-reg/gdb/testsuite/gdb.base/jit-so.exp ...
FAIL: gdb.base/jit-so.exp: one_jit_test-1: continue to breakpoint: break here 2 (the program exited)
FAIL: gdb.base/jit-so.exp: one_jit_test-2: continue to breakpoint: break here 2 (the program exited)
since:
85af34ee0211eedf8d30a5c44dfc59dddf8b512a is the first bad commit
commit 85af34ee0211eedf8d30a5c44dfc59dddf8b512a
Author: Pedro Alves <palves@redhat.com>
Date: Thu Mar 31 19:28:47 2016 +0100
Add regression test for PR gdb/19858 (JIT code registration on attach)
The compiled code's .debug_line is wrong (for the simplistic approach of GDB
to put a breakpoint on the first address belonging to that source line) and so
GDB misses the breakpoint at the last line:
WAIT_FOR_GDB; return 0; /* gdb break here 2 */
Most of the patch is just about reindentation, no changes there.
gdb/testsuite/ChangeLog
2016-04-08 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix compatibility with gcc-4.8.5-4.el7.x86_64.
* gdb.base/jit-main.c: Use exit after usage.
|
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$ GDBHISTFILE=/tmp/gdbhistfile runtest gdb.base/gdbhistsize-history.exp gdb.base/gdbinit-history.exp
Running ./gdb.base/gdbinit-history.exp ...
FAIL: gdb.base/gdbinit-history.exp: home=gdbinit-history/unlimited gdbhistsize=1000: show commands
FAIL: gdb.base/gdbinit-history.exp: home=gdbinit-history/unlimited gdbhistsize=foo: show commands
Running ./gdb.base/gdbhistsize-history.exp ...
FAIL: gdb.base/gdbhistsize-history.exp: histsize=: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=20: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize= 20 : show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=-5: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=not_an_integer: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=10zab: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=-5ab: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=99999999999999999999999999999999999: show commands
FAIL: gdb.base/gdbhistsize-history.exp: histsize=50: show commands
This happens for my setup due to my:
$ grep GDB ~/.bashrc
export GDBHISTFILE="$HOME/.gdb_history"
gdb/testsuite/ChangeLog
2016-04-07 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.base/gdbhistsize-history.exp: Save and unset GDBHISTFILE and
GDBHISTSIZE prior to the tests.
* gdb.base/gdbinit-history.exp: Likewise.
|
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Commit 6e774b13c3b8 (Make ftrace tests work with remote targets) made
a few gdb.compile/compile.exp tests disappear:
-PASS: gdb.compile/compile.exp: call shared library function
-PASS: gdb.compile/compile.exp: expect 1
-PASS: gdb.compile/compile.exp: modify shared library variable
-PASS: gdb.compile/compile.exp: expect 15
This is because the test uses ldflags instead of using the shlib
option, so it misses linking with -rpath, resulting in:
(gdb) run
Starting program: .../compile/compile-shlib
.../compile/compile-shlib: error while loading shared libraries: compile-shlib.so: cannot open shared object file: No such file or directory
[Inferior 1 (process 18014) exited with code 0177]
We were missing a gdb_load_shlibs call, which is needed for remote
testing.
gdb/testsuite/ChangeLog:
2015-04-07 Pedro Alves <palves@redhat.com>
* gdb.compile/compile.exp: Use gdb_compile with "shlib=" option
instead of build_executable. Use gdb_load_shlibs.
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I see the following fail on aarch64-linux
break void_func
Breakpoint 2 at 0x4007a0: file gdb/testsuite/gdb.reverse/finish-reverse.c, line 44.
(gdb) PASS: gdb.reverse/finish-reverse-bkpt.exp: set breakpoint on void_func
continue
Continuing.
Breakpoint 2, void_func () at gdb/testsuite/gdb.reverse/finish-reverse.c:44^M
44 void_test = 1; /* VOID FUNC */^M
(gdb) PASS: gdb.reverse/finish-reverse-bkpt.exp: continue to breakpoint: void_func
break *void_func^M
Note: breakpoint 2 also set at pc 0x4007a0.^M
Breakpoint 3 at 0x4007a0: file gdb/testsuite/gdb.reverse/finish-reverse.c, line 44.
(gdb) PASS: gdb.reverse/finish-reverse-bkpt.exp: set breakpoint at void_func's entry
reverse-finish^M
Run back to call of #0 void_func () at gdb/testsuite/gdb.reverse/finish-reverse.c:44
main (argc=1, argv=0x7ffffffb78) at gdb/testsuite/gdb.reverse/finish-reverse.c:98
98 void_func (); /* call to void_func */^M
(gdb) FAIL: gdb.reverse/finish-reverse-bkpt.exp: reverse-finish from void_func trips breakpoint at entry
The test assumes that brekapoints on "void_func" and "*void_func" are
set on different places because of function prologue. However, on
aarch64-linux, there is no prologue in void_func, so two breakpoints
are set at the same place (0x4007a0).
(gdb) disassemble void_func
Dump of assembler code for function void_func:
0x00000000004007a0 <+0>: adrp x0, 0x410000
0x00000000004007a4 <+4>: add x0, x0, #0xc14
0x00000000004007a8 <+8>: mov w1, #0x1
0x00000000004007ac <+12>: str w1, [x0]
0x00000000004007b0 <+16>: ret
The fix to this problem is to single step forward before setting
breakpoint on *void_func.
gdb/testsuite:
2016-04-07 Yao Qi <yao.qi@linaro.org>
* gdb.reverse/finish-reverse-bkpt.exp: Use temporary breakpoint.
Execute "si" command.
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I see the fail on aarch64-linux,
(gdb) reverse-next
Breakpoint 2, callee () at /home/yao/SourceCode/gnu/gdb/git/gdb/testsuite/gdb.reverse/step-reverse.c:26^M
26 myglob++; return 0; /* ARRIVED IN CALLEE */
(gdb) FAIL: gdb.reverse/next-reverse-bkpt-over-sr.exp: reverse-next over call trips user breakpoint at function entry
The test expects program stops at line 25, but program stops at line 26.
(gdb) maintenance info line-table
objfile: /scratch/yao/gdb/build-git/aarch64-linux-gnu/gdb/testsuite/outputs/gdb.reverse/next-reverse-bkpt-over-sr/next-reverse-bkpt-over-sr ((struct objfile *) 0x613000002880)
compunit_symtab: ((struct compunit_symtab *) 0x621000121760)
symtab: /home/yao/SourceCode/gnu/gdb/git/gdb/testsuite/gdb.reverse/step-reverse.c ((struct symtab *) 0x6210001217e0)
linetable: ((struct linetable *) 0x6210001520d0):
INDEX LINE ADDRESS
0 25 0x0000000000400890
1 26 0x0000000000400890
2 27 0x00000000004008b0
(gdb) disassemble callee
Dump of assembler code for function callee:
0x0000000000400890 <+0>: adrp x0, 0x410000
0x0000000000400894 <+4>: add x0, x0, #0xcac
the line-table show that the first instruction of function callee is
mapped line 25 and 26. I am not sure the line-table is correct, but
it is not the point of this test. The goal of this test is to test
program hits the breakpoint on the first instruction of function after
'reverse-next', so I change this test to expect the breakpoint number
the program hits.
gdb/testsuite:
2016-04-07 Yao Qi <yao.qi@linaro.org>
* gdb.reverse/next-reverse-bkpt-over-sr.exp: Match the breakpoint
number instead of the comments on some line.
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Some test fails in gdb.reverse/break-reverse.exp on arm-linux lead me
seeing the following error message,
continue^M
Continuing.^M
Cannot remove breakpoints because program is no longer writable.^M
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Further execution is probably impossible.^M
^M
Breakpoint 3, bar () at /home/yao/SourceCode/gnu/gdb/git/gdb/testsuite/gdb.reverse/break-reverse.c:22^M
22 xyz = 2; /* break in bar */^M
(gdb) PASS: gdb.reverse/break-reverse.exp: continue to breakpoint: bar backward
this is caused by two entries in record_full_breakpoints, and their addr
is the same, but in_target_beneath is different.
during the record, we do continue,
Continuing.
infrun: clear_proceed_status_thread (Thread 13772.13772)
infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: step-over queue now empty
infrun: resuming [Thread 13772.13772] for step-over
infrun: skipping breakpoint: stepping past insn at: 0x8620
Sending packet: $Z0,85f4,4#1d...Packet received: OK <----
.....
Sending packet: $vCont;c#a8...infrun: target_wait (-1.0.0, status) =
infrun: -1.0.0 [process -1],
infrun: status->kind = ignore
infrun: TARGET_WAITKIND_IGNORE
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: -1.0.0 [process -1],
infrun: status->kind = ignore
infrun: TARGET_WAITKIND_IGNORE
infrun: prepare_to_wait
Packet received: T05swbreak:;0b:9cf5ffbe;0d:9cf5ffbe;0f:f4850000;thread:p35cc.35cc;core:1;
Sending packet: $Z0,85f4,4#1d...Packet received: OK <-----
....
Sending packet: $z0,85f4,4#3d...Packet received: OK <-----
we can see breakpoint on 0x85f4 are inserted *twice*, but only removed
once. That is fine to remote target, because Z/z packets are
idempotent, but there is a leftover in record_full_breakpoints
in record-full target. The flow can be described as below,
record_full_breakpoints remote target
-----------------------------------------------------------------------
forward execution, continue, in_target_beneath 1 breakpoint inserted
insert breakpoints on 0x85f4 in_target_beneath 1
twice
program stops,
remove breakpoint on 0x85f4 in_target_beneath 1 breakpoint removed
reverse execution, continue, in_target_beneath 1 none is requested
insert breakpoints on 0x85f4, in_target_beneath 0
program stops,
remote breakpoint on 0x85f4, in_target_beneath 0 request to remove,
but GDBserver
doesn't know
now, the question is why breakoint on 0x85f4 is inserted twice? One
is the normal breakpoint, and the other is the single step breakpoint.
GDB inserts single step breakpoint to do single step. When program
stops at 0x85f4, both of them are set on 0x85f4, and GDB deletes
single step breakpoint, so in update_global_location_list, this
breakpoint location is no longer found, GDB call
force_breakpoint_reinsertion to mark it condition_updated, and insert
it again.
The reason force_breakpoint_reinsertion is called to update the
conditions in the target side, because the conditions may be
changed. My original fix is to not call force_breakpoint_reinsertion
if OLD_LOC->cond is NULL, but it is not correct if another location
on the same address has condition, GDB doesn't produce condition for
target side, but GDB should do.
Then, I change my mind back to make record-full handling breakpoint
idempotent, to align with remote target. Before insert a new entry
into record_full_breakpoints, look for existing one on the same
address first. I also add an assert on
"bp->in_target_beneath == in_target_beneath", to be safer.
gdb:
2016-04-07 Yao Qi <yao.qi@linaro.org>
* record-full.c (record_full_insert_breakpoint): Return
early if entry on the address is found in
record_full_breakpoints.
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record_full_insert_breakpoint
I notice that bp_tgt won't be fully initialized if to_insert_breakpoint
isn't called in record_full_insert_breakpoint, and bp_tgt->reqstd_address
is zero, so an entry is added to record_full_breakpoints, but its address
is zero, which is wrong. This patch is to call gdbarch_breakpoint_from_pc
in the else branch to set bp_tgt->reqstd_address and bp_tgt->placed_size.
gdb:
2016-04-07 Yao Qi <yao.qi@linaro.org>
* record-full.c (record_full_insert_breakpoint): Set
bp_tgt->reqstd_address and bp_tgt->placed_size.
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This patch eliminates an error thrown when accessing the value of a
pointer to a structure where the pointer has been optimized out and
'set print object' is 'on'. The error shows up as the rather ugly
value of the pointer variable in Eclipse.
If 'set print object' is 'on', GDB tries to determine the actual
(derived) type of the object rather than the declared type, which
requires dereferencing the pointer, which in this cases throws an
error because the pointer has been optimized out.
The fix is to simply ignore the 'print object on' setting for
pointers or references to structures when they have been optimized
out. This means we just get the declared type instead of the actual
type, because in this case that's the best that we can do.
To implement the fix, value_optimized_out was modified so that it
no longer throws an error when it fails to fetch the specified
value. Instead, it just checks value->optimized_out. If we can't
definitively say that the value is optimized out, then we assume
it is not.
gdb/ChangeLog:
2016-04-06 Don Breazeal <donb@codesourcery.com>
* value.c (value_actual_type): Don't try to get rtti type
of the value if it has been optimized out.
(value_optimized_out): If a memory access error occurs,
just check vaue->optimized_out.
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