I found the documentation for -dprintf-insert a bit unclear. It
didn't mention the possibility of multiple arguments, and I also
noticed that it implied that the format parameter is optional, which
it is not.
While looking into this I also noticed a few comments in the
implementation that could also be improved.
Then, I noticed a repeated call to strlen in a loop condition, so I
fixed this up as well.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Same idea as previous patches, but for about_to_proceed. We only need
(and want, as far as the mi_interp implementation is concerned) to
notify the interpreter that caused the proceed.
Change-Id: Id259bca10dbc3d43d46607ff7b95243a9cbe2f89
Same idea as previous patches, but for inferior_disappeared.
For symmetry with on_inferior_appeared, I named this one
on_inferior_disappeared, despite the observer being called
inferior_exit. This is called when detaching an inferior, so I think
that calling it "disappeared" is a bit less misleading (the observer
should probably be renamed later).
Change-Id: I372101586bc9454997953c1e540a2a6685f53ef6
Same idea as previous patches, but for inferior_added.
mi_interp::init avoided using mi_inferior_added, since, as the comment
used to say, it would notify all MI interpreters. Now, it's easy to
only notify the new interpreter, so it's possible to just call the
on_inferior_added method in mi_interp::init.
Change-Id: I0eddbd5367217d1c982516982089913019ef309f
Same as previous patches, but for sync_execution_done. Except that
here, we only want to notify the interpreter that is executing the
command, not all interpreters.
Change-Id: I729c719447b5c5f29af65dbf6fed9132e2cd308b
Same as previous patch, but for exited. Remove the exited observable,
since nothing uses it anymore, and we don't have anything coming that
will use it.
Change-Id: I358cbea0159af56752dfee7510d6a86191e722bb
Same as previous patch, but for signal_exited. Remove the signal_exited
observable, since nothing uses it anymore, and we don't have anything
coming that will use it.
Change-Id: I0dca1eab76338bf27be755786e3dad3241698b10
Instead of having the interpreter code registering observers for the
signal_received observable, add a "signal_received" virtual method to
struct interp. Add a interps_notify_signal_received function that loops
over all UIs and calls the signal_received method on the interpreter.
Finally, add a notify_signal_received function that calls
interps_notify_signal_received and then notifies the observers. Replace
all existing notifications to the signal_received observers with calls
to notify_signal_received.
Before this patch, the CLI and MI code both register a signal_received
observer. These observer go over all UIs, and, for those that have a
interpreter of the right kind, print the stop notifiation.
After this patch, we have just one "loop over all UIs", inside
interps_notify_signal_received. Since the interp::on_signal_received
method gets called once for each interpreter, the implementations only
need to deal with the current interpreter (the "this" pointer).
The motivation for this patch comes from a future patch, that makes the
amdgpu code register an observer to print a warning after the CLI's
signal stop message. Since the amdgpu and the CLI code both use
observers, the order of the two messages is not stable, unless we define
the priority using the observer dependency system. However, the
approach of using virtual methods on the interpreters seems like a good
change anyway, I think it's more straightforward and simple to
understand than the current solution that uses observers. We are sure
that the amdgpu message gets printed after the CLI message, since
observers are notified after interpreters.
Keep the signal_received, even if nothing uses if, because we will be
using it in the upcoming amdgpu patch implementing the warning described
above.
Change-Id: I4d8614bb8f6e0717f4bfc2a59abded3702f23ac4
I stumbled on the mi_proceeded and running_result_record_printed
globals, which are shared by all MI interpreter instances (it's unlikely
that people use multiple MI interpreter instances, but it's possible).
After poking at it, I found this bug:
1. Start GDB in MI mode
2. Add a second MI interpreter with the new-ui command
3. Use -exec-run on the second interpreter
This is the output I get on the first interpreter:
=thread-group-added,id="i1"
~"Reading symbols from a.out...\n"
~"New UI allocated\n"
(gdb)
=thread-group-started,id="i1",pid="94718"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
And this is the output I get on the second intepreter:
=thread-group-added,id="i1"
(gdb)
-exec-run
=thread-group-started,id="i1",pid="94718"
=thread-created,id="1",group-id="i1"
*running,thread-id="all"
The problem here is that the `^running` reply to the -exec-run command
is printed on the wrong UI. It is printed on the first one, it should
be printed on the second (the one on which we sent the -exec-run).
What happens under the hood is that captured_mi_execute_command, while
executing a command for the second intepreter, clears the
running_result_record_printed and mi_proceeded globals.
mi_about_to_proceed then sets mi_proceeded. Then, mi_on_resume_1 gets
called for the first intepreter first. Since the
!running_result_record_printed && mi_proceeded
condition is true, it prints a ^running, and sets
running_result_record_printed. When mi_on_resume_1 gets called for the
second interpreter, running_result_record_printed is already set, so
^running is not printed there.
It took me a while to understand the relationship between these two
variables. I think that in the end, this is what we want to track:
1. When executing an MI command, take note if that command causes a
"proceed". This is done in mi_about_to_proceed.
2. In mi_on_resume_1, if the command indeed caused a "proceed", we want
to output a ^running record. And we want to remember that we did,
because...
3. Back in captured_mi_execute_command, if we did not output a
^running, we want to output a ^done.
Moving those two variables to the mi_interp struture appears to fix it.
Only for the interpreter doing the -exec-run command does the
running_result_record_printed flag get cleared, and therefore only or
that one does the ^running record get printed.
Add a new test for this, that does pretty much what the reproducer above
shows. Without the fix, the test fails because
mi_send_resuming_command_raw never sees the ^running record.
Change-Id: I63ea30e6cb61a8e1dd5ef03377e6003381a9209b
Tested-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>
I've had this patch for a while now and figured I'd update it and send
it. It changes MI commands to use a "const char * const" for their
argv parameter.
Regression tested on x86-64 Fedora 36.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
This adds a new Python function, gdb.execute_mi, that can be used to
invoke an MI command but get the output as a Python object, rather
than a string. This is done by implementing a new ui_out subclass
that builds a Python object.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=11688
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
This adds a second mi_parse constructor. This constructor takes a
command name and vector of arguments, and does not do any escape
processing. This also changes mi_parse::args to handle parse objects
created this new way.
This changes mi_parse::args to be a private member, retrieved via
accessor. It also changes this member to be a std::string. This
makes it simpler for a subsequent patch to implement different
behavior for argument parsing.
SUMMARY
The '--simple-values' argument to '-stack-list-arguments' and similar
GDB/MI commands does not take reference types into account, so that
references to arbitrarily large structures are considered "simple" and
printed. This means that the '--simple-values' argument cannot be used
by IDEs when tracing the stack due to the time taken to print large
structures passed by reference.
DETAILS
Various GDB/MI commands ('-stack-list-arguments', '-stack-list-locals',
'-stack-list-variables' and so on) take a PRINT-VALUES argument which
may be '--no-values' (0), '--all-values' (1) or '--simple-values' (2).
In the '--simple-values' case, the command is supposed to print the
name, type, and value of variables with simple types, and print only the
name and type of variables with compound types.
The '--simple-values' argument ought to be suitable for IDEs that need
to update their user interface with the program's call stack every time
the program stops. However, it does not take C++ reference types into
account, and this makes the argument unsuitable for this purpose.
For example, consider the following C++ program:
struct s {
int v[10];
};
int
sum(const struct s &s)
{
int total = 0;
for (int i = 0; i < 10; ++i) total += s.v[i];
return total;
}
int
main(void)
{
struct s s = { { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 } };
return sum(s);
}
If we start GDB in MI mode and continue to 'sum', the behaviour of
'-stack-list-arguments' is as follows:
(gdb)
-stack-list-arguments --simple-values
^done,stack-args=[frame={level="0",args=[{name="s",type="const s &",value="@0x7fffffffe310: {v = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}}"}]},frame={level="1",args=[]}]
Note that the value of the argument 's' was printed, even though 's' is
a reference to a structure, which is not a simple value.
See https://github.com/microsoft/MIEngine/pull/673 for a case where this
behaviour caused Microsoft to avoid the use of '--simple-values' in
their MIEngine debug adapter, because it caused Visual Studio Code to
take too long to refresh the call stack in the user interface.
SOLUTIONS
There are two ways we could fix this problem, depending on whether we
consider the current behaviour to be a bug.
1. If the current behaviour is a bug, then we can update the behaviour
of '--simple-values' so that it takes reference types into account:
that is, a value is simple if it is neither an array, struct, or
union, nor a reference to an array, struct or union.
In this case we must add a feature to the '-list-features' command so
that IDEs can detect that it is safe to use the '--simple-values'
argument when refreshing the call stack.
2. If the current behaviour is not a bug, then we can add a new option
for the PRINT-VALUES argument, for example, '--scalar-values' (3),
that would be suitable for use by IDEs.
In this case we must add a feature to the '-list-features' command
so that IDEs can detect that the '--scalar-values' argument is
available for use when refreshing the call stack.
PATCH
This patch implements solution (1) as I think the current behaviour of
not printing structures, but printing references to structures, is
contrary to reasonable expectation.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29554
I'd like to move some things so they become methods on struct ui. But
first, I think that struct ui and the related things are big enough to
deserve their own file, instead of being scattered through top.{c,h} and
event-top.c.
Change-Id: I15594269ace61fd76ef80a7b58f51ff3ab6979bc
Latest libc++[1] causes transitive include to <locale> when
<mutex> or <thread> header is included. This causes
gdb to not build[2] since <locale> defines isupper/islower etc.
functions that are explicitly macroed-out in safe-ctype.h to
prevent their use.
Use the suggestion from libc++ to include <locale> internally when
building in C++ mode to avoid build errors.
Use safe-gdb-ctype.h as the include instead of "safe-ctype.h"
to keep this isolated to gdb since rest of binutils
does not seem to use much C++.
[1]: https://reviews.llvm.org/D144331
[2]: https://issuetracker.google.com/issues/277967395
I noticed the following behaviour:
$ gdb -q -i=mi /tmp/hello.x
=thread-group-added,id="i1"
=cmd-param-changed,param="print pretty",value="on"
~"Reading symbols from /tmp/hello.x...\n"
(gdb)
-break-insert -p 99 main
^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x0000000000401198",func="main",file="/tmp/hello.c",fullname="/tmp/hello.c",line="18",thread-groups=["i1"],thread="99",times="0",original-location="main"}
(gdb)
info breakpoints
&"info breakpoints\n"
~"Num Type Disp Enb Address What\n"
~"1 breakpoint keep y 0x0000000000401198 in main at /tmp/hello.c:18\n"
&"../../src/gdb/thread.c:1434: internal-error: print_thread_id: Assertion `thr != nullptr' failed.\nA problem internal to GDB has been detected,\nfurther debugging may prove unreliable."
&"\n"
&"----- Backtrace -----\n"
&"Backtrace unavailable\n"
&"---------------------\n"
&"\nThis is a bug, please report it."
&" For instructions, see:\n"
&"<https://www.gnu.org/software/gdb/bugs/>.\n\n"
Aborted (core dumped)
What we see here is that when using the MI a user can create
thread-specific breakpoints for non-existent threads. Then if we try
to use the CLI 'info breakpoints' command GDB throws an assertion.
The assert is a result of the print_thread_id call when trying to
build the 'stop only in thread xx.yy' line; print_thread_id requires a
valid thread_info pointer, which we can't have for a non-existent
thread.
In contrast, when using the CLI we see this behaviour:
$ gdb -q /tmp/hello.x
Reading symbols from /tmp/hello.x...
(gdb) break main thread 99
Unknown thread 99.
(gdb)
The CLI doesn't allow a breakpoint to be created for a non-existent
thread. So the 'info breakpoints' command is always fine.
Interestingly, the MI -break-info command doesn't crash, this is
because the MI uses global thread-ids, and so never calls
print_thread_id. However, GDB does support using CLI and MI in
parallel, so we need to solve this problem.
One option would be to change the CLI behaviour to allow printing
breakpoints for non-existent threads. This would preserve the current
MI behaviour.
The other option is to pull the MI into line with the CLI and prevent
breakpoints being created for non-existent threads. This is good for
consistency, but is a breaking change for the MI.
In the end I figured that it was probably better to retain the
consistent CLI behaviour, and just made the MI reject requests to
place a breakpoint on a non-existent thread. The only test we had
that depended on the old behaviour was
gdb.mi/mi-thread-specific-bp.exp, which was added by me in commit:
commit 2fd9a436c8
Date: Fri Feb 17 10:48:06 2023 +0000
gdb: don't duplicate 'thread' field in MI breakpoint output
I certainly didn't intend for this test to rely on this feature of the
MI, so I propose to update this test to only create breakpoints for
threads that exist.
Actually, I've added a new test that checks the MI rejects creating a
breakpoint for a non-existent thread, and I've also extended the test
to run with the separate MI/CLI UIs, and then tested 'info
breakpoints' to ensure this command doesn't crash.
I've extended the documentation of the `-p` flag to explain the
constraints better.
I have also added a NEWS entry just in case someone runs into this
issue, at least then they'll know this change in behaviour was
intentional.
One thing that I did wonder about while writing this patch, is whether
we should treat requests like this, on both the MI and CLI, as another
form of pending breakpoint, something like:
(gdb) break foo thread 9
Thread 9 does not exist.
Make breakpoint pending on future thread creation? (y or [n]) y
Breakpoint 1 (foo thread 9) pending.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <PENDING> foo thread 9
Don't know if folk think that would be a useful idea or not? Either
way, I think that would be a separate patch from this one.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
I noticed that this observable was never notified, which means we can
probably safely remove it. The notification was removed in:
commit 243a925328
Author: Pedro Alves <palves@redhat.com>
Date: Wed Sep 9 18:23:24 2015 +0100
Replace "struct continuation" mechanism by something more extensible
print_end_stepping_range_reason in turn becomes unused, so remote it as
well.
Change-Id: If5da5149276c282d2540097c8c4327ce0f70431a
I think that the language_auto enumerator and the auto_language class
can be removed. There isn't really an "auto" language, it's only a
construct of the "set language" command to say "pick the appropriate
language automatically". But "auto" is never the current language. The
`current_language` points to the current effective language, and the
fact that we're in "auto language" mode is noted by the language_mode
global.
- Change set_language to handle the "auto" (and "local", which is a
synonym) early, instead of in the for loop. I think it makes the two
cases (auto vs explicit language) more clearly separated anyway.
- Adjust add_set_language_command to hard-code the "auto" string,
instead of using the "auto" language definition.
- Remove auto_language, rename auto_or_unknown_language to
unknown_language and move the bits of the existing unknown_language
in there.
- Remove the set_language at the end of _initialize_language. I think
it's not needed, because we call set_language in gdb_init, after all
_initialize functions are called. There is some chance that an
_initialize function that runs after _initialize_language implicitly
depends on current_language being set, but my testsuite runs haven't
found anything like that.
- Use language_unknown instead of language_auto when creating a minimal
symbol (minimal_symbol_reader::record_full). I think that this value
is used to indicate that we don't know the symbol of the minimal
symbol (yet), so language_unknown makes sense to me. Update a
condition accordingly in ada-lang.c. symbol_find_demangled_name also
appears to "normalize" this value from "unknown" to "auto", remove
that part and update the condition to just check for
language_unknown.
Change-Id: I47bcd6c15f607d9818f2e6e413053c2dc8ec5034
Reviewed-By: Tom Tromey <tom@tromey.com>
Make find_thread_ptid (the overload that takes a process_stratum_target)
a method of process_stratum_target.
Change-Id: Ib190a925a83c6b93e9c585dc7c6ab65efbdd8629
Reviewed-By: Tom Tromey <tom@tromey.com>
The mi_version function is unused, and I think it's better overall if
it is never used. This patch removes it. Tested by rebuilding.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
This changes linetables to not add the text offset to the addresses
they contain. I did this in a few steps, necessarily combined
together in one patch: I renamed the 'pc' member to 'm_pc', added the
appropriate accessors, and then recompiled. Then I fixed all the
errors. Where possible I generally chose to use the raw_pc accessor,
as it is less expensive.
Note that this patch discounts the possibility that the text section
offset might cause wraparound in the addresses in the line table.
However, this was already discounted -- in particular,
objfile_relocate1 did not re-sort the table in this scenario. (There
was a bug open about this, but as far as I can tell this has never
happened, it's not even clear what inspired that bug.)
Approved-By: Simon Marchi <simon.marchi@efficios.com>
