This patch changes the docstring self-test to verify that there is no
trailing whitespace at the end of lines. A few existing docstrings
had to be updated.
Most files including gdbcmd.h currently rely on it to access things
actually declared in cli/cli-cmds.h (setlist, showlist, etc). To make
things easy, replace all includes of gdbcmd.h with includes of
cli/cli-cmds.h. This might lead to some unused includes of
cli/cli-cmds.h, but it's harmless, and much faster than going through
the 170 or so files by hand.
Change-Id: I11f884d4d616c12c05f395c98bbc2892950fb00f
Approved-By: Tom Tromey <tom@tromey.com>
Move some declarations related to the "quit" machinery from defs.h to
event-top.h. Most of the definitions associated to these declarations
are in event-top.c. The exceptions are `quit()` and `maybe_quit()`,
that are defined in utils.c. For consistency, move these two
definitions to event-top.c.
Include "event-top.h" in many files that use these things.
Change-Id: I6594f6df9047a9a480e7b9934275d186afb14378
Approved-By: Tom Tromey <tom@tromey.com>
Currently, when the current thread is running, you can print global
variables. However, if you try to set a watchpoint on the same
globals, GDB errors out, complaining that the selected thread is
running. Like so:
(gdb) c&
Continuing.
(gdb) p global
$1 = 1098377287
(gdb) watch global
Selected thread is running.
This patch makes setting the watchpoint work. You'll now get:
(gdb) c&
Continuing.
(gdb) [New Thread 0x7ffff7d6e640 (LWP 434993)]
[New Thread 0x7ffff756d640 (LWP 434994)]
p global
$1 = 88168
(gdb) watch global
Hardware watchpoint 2: global
(gdb) [Switching to Thread 0x7ffff7d6e640 (LWP 434993)]
Thread 2 "function0" hit Hardware watchpoint 2: global
Old value = 185420
New value = 185423
int_return () at threads.c:39
39 }
The problem is that update_watchpoint calls get_selected_frame
unconditionally. We can skip it if the watchpoint expression is only
watching globals.
This adds a testcase that exercises both all-stop and non-stop, and
also software and hardware watchpoints. It is kfailed for software
watchpoints, as those require another fix not handled by this patch
(the sw watchpoint doesn't fire because GDB doesn't force the
running-free thread to switch to single-stepping).
Change-Id: I68ca948541aea3edd4f70741f272f543187abe40
I noticed in code_breakpoint::code_breakpoint that we are calling
update_dprintf_command_list once for each breakpoint location, when we
really only need to call this once per breakpoint -- the data updated
by this function, the breakpoint command list -- is per breakpoint,
not per breakpoint location. Calling update_dprintf_command_list
multiple times is just wasted effort, there's no per location error
checking, we don't even pass the current location to the function.
This commit moves the update_dprintf_command_list call outside of the
per-location loop.
There should be no user visible changes after this commit.
Given the changes in the previous couple of commits, this commit
cleans up some of the asserts and 'if' checks related to the
extra_string within a dprintf breakpoint.
This commit:
1. Adds some asserts to update_dprintf_command_list about the
breakpoint type, and that the extra_string is not nullptr,
2. Given that we know extra_string is not nullptr (this is enforced
when the breakpoint is created), we can simplify
code_breakpoint::code_breakpoint -- it no longer needs to check for
the extra_string is nullptr case,
3. In dprintf_breakpoint::re_set we can remove the assert (this will
be checked within update_dprintf_command_list, we can also remove
the redundant 'if' check.
There should be no user visible changes after this commit.
I noticed in update_dprintf_command_list that we handle the case where
the bp_dprintf style breakpoint doesn't have a format and args string.
However, I don't believe such a situation is possible. The obvious
approach certainly already catches this case:
(gdb) dprintf main
Format string required
If it is possible to create a dprintf breakpoint without a format and
args string then I think we should be catching this case and handling
it at creation time, rather than having GDB just ignore the situation
later on.
And so, I propose that we change the 'if' that ignores the case where
the format/args string is empty, and instead assert that we do always
have a format/args string. The original code, that handled an empty
format/args string has existed since commit e7e0cddfb0, which is
when dprintf support was added to GDB.
If I'm correct and this situation can't ever happen then there should
be no user visible changes after this commit.
The goal of this commit is to better define the API for
create_breakpoint especially around the use of extra_string and
parse_extra. This will be useful in the next commit when I plan to
make some changes to create_breakpoint.
This commit makes one possibly breaking change: until this commit it
was possible to create thread-specific dprintf breakpoint like this:
(gdb) dprintf call_me, thread 1 "%s", "hello"
Dprintf 2 at 0x401152: file /tmp/hello.c, line 8.
(gdb) info breakpoints
Num Type Disp Enb Address What
2 dprintf keep y 0x0000000000401152 in call_me at /tmp/hello.c:8 thread 1
stop only in thread 1
printf "%s", "hello"
(gdb)
This feature of dprintf was not documented, was not tested, and is
slightly different in syntax to how we create thread specific
breakpoints and/or watchpoints -- the thread condition appears after
the first ','.
I believe that this worked at all was simply by luck. We happen to
pass the parse_extra flag as true from dprintf_command to
create_breakpoint.
So in this commit I made the choice to change this. We now pass
parse_extra as false from dprintf_command to create_breakpoint. With
this done it is assumed that the only thing in the extra_string is the
dprintf format and arguments.
Beyond this change I've updated the comment on create_breakpoint in
breakpoint.h, and I've then added some asserts into
create_breakpoint as well as moving around some of the error
handling.
- We now assert on the incoming argument values,
- I've moved an error check to sit after the call to
find_condition_and_thread_for_sals, this ensures the extra_string
was parsed correctly,
In dprintf_command:
- We now throw an error if there is no format string after the
dprintf location. This error was already being thrown, but was
being caught later in the process. With this change we catch the
missing string earlier,
- And, as mentioned earlier, we pass parse_extra as false when
calling create_breakpoint,
In create_tracepoint_from_upload:
- We now throw an error if the parsed location doesn't completely
consume the addr_str variable. This error has now effectively
moved out of create_breakpoint.
This commit extends the asserts on create_breakpoint (in the header
file), and adds some additional assertions into the definition.
The new assert confirms that when the thread and inferior information
is going to be parsed from the extra_string, then the thread and
inferior arguments should be -1. That is, the caller of
create_breakpoint should not try to create a thread/inferior specific
breakpoint by *both* specifying thread/inferior *and* asking to parse
the extra_string, it's one or the other.
There should be no user visible changes after this commit.
Now that defs.h, server.h and common-defs.h are included via the
`-include` option, it is no longer necessary for source files to include
them. Remove all the inclusions of these files I could find. Update
the generation scripts where relevant.
Change-Id: Ia026cff269c1b7ae7386dd3619bc9bb6a5332837
Approved-By: Pedro Alves <pedro@palves.net>
This commit fixes bug PR 28942, that is, creating a conditional
breakpoint in a multi-threaded inferior, where the breakpoint
condition includes an inferior function call.
Currently, when a user tries to create such a breakpoint, then GDB
will fail with:
(gdb) break infcall-from-bp-cond-single.c:61 if (return_true ())
Breakpoint 2 at 0x4011fa: file /tmp/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/infcall-from-bp-cond-single.c, line 61.
(gdb) continue
Continuing.
[New Thread 0x7ffff7c5d700 (LWP 2460150)]
[New Thread 0x7ffff745c700 (LWP 2460151)]
[New Thread 0x7ffff6c5b700 (LWP 2460152)]
[New Thread 0x7ffff645a700 (LWP 2460153)]
[New Thread 0x7ffff5c59700 (LWP 2460154)]
Error in testing breakpoint condition:
Couldn't get registers: No such process.
An error occurred while in a function called from GDB.
Evaluation of the expression containing the function
(return_true) will be abandoned.
When the function is done executing, GDB will silently stop.
Selected thread is running.
(gdb)
Or, in some cases, like this:
(gdb) break infcall-from-bp-cond-simple.c:56 if (is_matching_tid (arg, 1))
Breakpoint 2 at 0x401194: file /tmp/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/infcall-from-bp-cond-simple.c, line 56.
(gdb) continue
Continuing.
[New Thread 0x7ffff7c5d700 (LWP 2461106)]
[New Thread 0x7ffff745c700 (LWP 2461107)]
../../src.release/gdb/nat/x86-linux-dregs.c:146: internal-error: x86_linux_update_debug_registers: Assertion `lwp_is_stopped (lwp)' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
The precise error depends on the exact thread state; so there's race
conditions depending on which threads have fully started, and which
have not. But the underlying problem is always the same; when GDB
tries to execute the inferior function call from within the breakpoint
condition, GDB will, incorrectly, try to resume threads that are
already running - GDB doesn't realise that some threads might already
be running.
The solution proposed in this patch requires an additional member
variable thread_info::in_cond_eval. This flag is set to true (in
breakpoint.c) when GDB is evaluating a breakpoint condition.
In user_visible_resume_ptid (infrun.c), when the in_cond_eval flag is
true, then GDB will only try to resume the current thread, that is,
the thread for which the breakpoint condition is being evaluated.
This solves the problem of GDB trying to resume threads that are
already running.
The next problem is that inferior function calls are assumed to be
synchronous, that is, GDB doesn't expect to start an inferior function
call in thread #1, then receive a stop from thread #2 for some other,
unrelated reason. To prevent GDB responding to an event from another
thread, we update fetch_inferior_event and do_target_wait in infrun.c,
so that, when an inferior function call (on behalf of a breakpoint
condition) is in progress, we only wait for events from the current
thread (the one evaluating the condition).
In do_target_wait I had to change the inferior_matches lambda
function, which is used to select which inferior to wait on.
Previously the logic was this:
auto inferior_matches = [&wait_ptid] (inferior *inf)
{
return (inf->process_target () != nullptr
&& ptid_t (inf->pid).matches (wait_ptid));
};
This compares the pid of the inferior against the complete ptid we
want to wait on. Before this commit wait_ptid was only ever
minus_one_ptid (which is special, and means any process), and so every
inferior would match.
After this commit though wait_ptid might represent a specific thread
in a specific inferior. If we compare the pid of the inferior to a
specific ptid then these will not match. The fix is to compare
against the pid extracted from the wait_ptid, not against the complete
wait_ptid itself.
In fetch_inferior_event, after receiving the event, we only want to
stop all the other threads, and call inferior_event_handler with
INF_EXEC_COMPLETE, if we are not evaluating a conditional breakpoint.
If we are, then all the other threads should be left doing whatever
they were before. The inferior_event_handler call will be performed
once the breakpoint condition has finished being evaluated, and GDB
decides to stop or not.
The final problem that needs solving relates to GDB's commit-resume
mechanism, which allows GDB to collect resume requests into a single
packet in order to reduce traffic to a remote target.
The problem is that the commit-resume mechanism will not send any
resume requests for an inferior if there are already events pending on
the GDB side.
Imagine an inferior with two threads. Both threads hit a breakpoint,
maybe the same conditional breakpoint. At this point there are two
pending events, one for each thread.
GDB selects one of the events and spots that this is a conditional
breakpoint, GDB evaluates the condition.
The condition includes an inferior function call, so GDB sets up for
the call and resumes the one thread, the resume request is added to
the commit-resume queue.
When the commit-resume queue is committed GDB sees that there is a
pending event from another thread, and so doesn't send any resume
requests to the actual target, GDB is assuming that when we wait we
will select the event from the other thread.
However, as this is an inferior function call for a condition
evaluation, we will not select the event from the other thread, we
only care about events from the thread that is evaluating the
condition - and the resume for this thread was never sent to the
target.
And so, GDB hangs, waiting for an event from a thread that was never
fully resumed.
To fix this issue I have added the concept of "forcing" the
commit-resume queue. When enabling commit resume, if the force flag
is true, then any resumes will be committed to the target, even if
there are other threads with pending events.
A note on authorship: this patch was based on some work done by
Natalia Saiapova and Tankut Baris Aktemur from Intel[1]. I have made
some changes to their work in this version.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28942
[1] https://sourceware.org/pipermail/gdb-patches/2020-October/172454.html
Co-authored-by: Natalia Saiapova <natalia.saiapova@intel.com>
Co-authored-by: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Reviewed-By: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Tested-By: Luis Machado <luis.machado@arm.com>
Tested-By: Keith Seitz <keiths@redhat.com>
The output of "info breakpoints" includes breakpoint, watchpoint,
tracepoint, and catchpoint if they are created, so it should show
all the four types are deleted in the output of "info breakpoints"
to report empty list after "delete breakpoints".
It should also change the output of "delete breakpoints" to make it
clear that watchpoints, tracepoints, and catchpoints are also being
deleted. This is suggested by Guinevere Larsen, thank you.
$ make check-gdb TESTS="gdb.base/access-mem-running.exp"
$ gdb/gdb gdb/testsuite/outputs/gdb.base/access-mem-running/access-mem-running
[...]
(gdb) break main
Breakpoint 1 at 0x12000073c: file /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c, line 32.
(gdb) watch global_counter
Hardware watchpoint 2: global_counter
(gdb) trace maybe_stop_here
Tracepoint 3 at 0x12000071c: file /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c, line 27.
(gdb) catch fork
Catchpoint 4 (fork)
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x000000012000073c in main at /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c:32
2 hw watchpoint keep y global_counter
3 tracepoint keep y 0x000000012000071c in maybe_stop_here at /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c:27
not installed on target
4 catchpoint keep y fork
Without this patch:
(gdb) delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) info breakpoints 3
No breakpoint or watchpoint matching '3'.
With this patch:
(gdb) delete breakpoints
Delete all breakpoints, watchpoints, tracepoints, and catchpoints? (y or n) y
(gdb) info breakpoints
No breakpoints, watchpoints, tracepoints, or catchpoints.
(gdb) info breakpoints 3
No breakpoint, watchpoint, tracepoint, or catchpoint matching '3'.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Approved-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Make the current_program_space reference bubble up one level.
Change-Id: Ide917aa306bff1872d961244901d79f65d2da62e
Approved-By: Andrew Burgess <aburgess@redhat.com>
By inspection, I believe that breakpoint_init_inferior doesn't call
anything that relies on the current program space or inferior. So,
add an inferior parameter, to make the current inferior / program space
references bubble up one level.
Change-Id: Ib07b7a6d360e324f6ae1aa502dd314b8cce421b7
Approved-By: Andrew Burgess <aburgess@redhat.com>
Make the current_program_space reference bubble up one level.
Change-Id: Idc8ed78d23bf3bb2969f6963d8cc049f26901c29
Approved-By: Andrew Burgess <aburgess@redhat.com>
`struct so_list` was recently renamed to `struct shobj` (in 3fe0dfd160
("gdb: rename struct so_list to shobj")). In hindsight, `solib` would
have been a better name. We have solib.c, the implementations in
solib-*.c, many functions with solib in their name, the solib_loaded /
solib_unloaded observables, etc.
Rename shobj to solib.
Change-Id: I0af1c7a9b29bdda027e9af633f6d37e1cfcacd5d
Approved-By: Tom Tromey <tom@tromey.com>
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
The previous patches are nearly enough to enable background DWARF
reading. However, this hack in language_defn::get_symbol_name_matcher
causes an early computation of current_language:
/* If currently in Ada mode, and the lookup name is wrapped in
'<...>', hijack all symbol name comparisons using the Ada
matcher, which handles the verbatim matching. */
if (current_language->la_language == language_ada
&& lookup_name.ada ().verbatim_p ())
return current_language->get_symbol_name_matcher_inner (lookup_name);
I considered various options here -- reversing the order of the
checks, or promoting the verbatim mode to not be a purely Ada feature
-- but in the end found that the few calls to this during startup
could be handled more directly.
In the JIT code, and in create_exception_master_breakpoint_hook, gdb
is really looking for a certain kind of symbol (text or data) using a
linkage name. Changing the lookup here is clearer and probably more
efficient as well.
In create_std_terminate_master_breakpoint, the lookup can't really be
done by linkage name (it would require relying on a certain mangling
scheme, and also may trip over versioned symbols) -- but we know that
this spot is C++-specific, and so the language ought to be temporarily
set to C++ here.
After this patch, the "file" case is much faster:
(gdb) file /tmp/gdb
2023-10-23 13:16:54.456 - command started
Reading symbols from /tmp/gdb...
2023-10-23 13:16:54.520 - command finished
Command execution time: 0.225906 (cpu), 0.064313 (wall)
When running test-case gdb.base/vfork-follow-parent.exp on powerpc64 (likewise
on s390x), I run into:
...
(gdb) PASS: gdb.base/vfork-follow-parent.exp: \
exec_file=vfork-follow-parent-exit: target-non-stop=on: non-stop=off: \
resolution_method=schedule-multiple: print unblock_parent = 1
continue^M
Continuing.^M
Reading symbols from vfork-follow-parent-exit...^M
^M
^M
Fatal signal: Segmentation fault^M
----- Backtrace -----^M
0x1027d3e7 gdb_internal_backtrace_1^M
src/gdb/bt-utils.c:122^M
0x1027d54f _Z22gdb_internal_backtracev^M
src/gdb/bt-utils.c:168^M
0x1057643f handle_fatal_signal^M
src/gdb/event-top.c:889^M
0x10576677 handle_sigsegv^M
src/gdb/event-top.c:962^M
0x3fffa7610477 ???^M
0x103f2144 for_each_block^M
src/gdb/dcache.c:199^M
0x103f235b _Z17dcache_invalidateP13dcache_struct^M
src/gdb/dcache.c:251^M
0x10bde8c7 _Z24target_dcache_invalidatev^M
src/gdb/target-dcache.c:50^M
...
or similar.
The root cause for the segmentation fault is that linux_is_uclinux gives an
incorrect result: it should always return false, given that we're running on a
regular linux system, but instead it returns first true, then false.
In more detail, the segmentation fault happens as follows:
- a program space with an address space is created
- a second program space is about to be created. maybe_new_address_space
is called, and because linux_is_uclinux returns true, maybe_new_address_space
returns false, and no new address space is created
- a second program space with the same address space is created
- a program space is deleted. Because linux_is_uclinux now returns false,
gdbarch_has_shared_address_space (current_inferior ()->arch ()) returns
false, and the address space is deleted
- when gdb uses the address space of the remaining program space, we run into
the segfault, because the address space is deleted.
Hardcoding linux_is_uclinux to false makes the test-case pass.
We leave addressing the root cause for the following commit in this series.
For now, prevent the segmentation fault by making the address space a refcounted
object.
This was already suggested here [1]:
...
A better solution might be to have the address spaces be reference counted
...
Tested on top of trunk on x86_64-linux and ppc64le-linux.
Tested on top of gdb-14-branch on ppc64-linux.
Co-Authored-By: Simon Marchi <simon.marchi@polymtl.ca>
PR gdb/30547
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30547
[1] https://sourceware.org/pipermail/gdb-patches/2023-October/202928.html
Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation. This patch does the following replacing:
- gdb::optional -> std::optional
- gdb::in_place -> std::in_place
- #include "gdbsupport/gdb_optional.h" -> #include <optional>
This change has mostly been done automatically. One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.
Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>
Remove get_current_regcache, inlining the call to get_thread_regcache in
callers. When possible, pass the right thread_info object known from
the local context. Otherwise, fall back to passing `inferior_thread ()`.
This makes the reference to global context bubble up one level, a small
step towards the long term goal of reducing the number of references to
global context (or rather, moving those references as close as possible
to the top of the call tree).
No behavior change expected.
Change-Id: Ifa6980c88825d803ea586546b6b4c633c33be8d6
I found some "break" statements that follow "return" or a call to a
noreturn function. These aren't needed, and the compiler would warn
if they were. So, this patch removes them.
Tested by rebuilding.
I stumbled across a few spots that mention that a function
"invalidates frame" and also assignments of NULL to a frame_info_ptr.
This code isn't harmful, but is also unnecessary since the
introduction of frame_info_ptr -- nowadays frame invalidations are
handled automatically.
Regression tested on x86-64 Fedora 38.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Now that so_list lists are implemented using intrusive_list, it doesn't
really make sense for the element type to be named "_list". Rename to
just `struct shobj` (`struct so` was deemed to be not greppable enough).
Change-Id: I1063061901298bb40fee73bf0cce44cd12154c0e
Approved-By: Pedro Alves <pedro@palves.net>
Reviewed-By: Reviewed-By: Lancelot Six <lancelot.six@amd.com>
Change these two fields, simplifying memory management and copying.
Change-Id: If2559284c515721e71e1ef56ada8b64667eebe55
Approved-By: Pedro Alves <pedro@palves.net>
Reviewed-By: Reviewed-By: Lancelot Six <lancelot.six@amd.com>
A subsequent patch changes so_list to be linked using
intrusive_list. Iterating an intrusive_list yields some references to
the list elements. Convert some functions accepting so_list objects to
take references, to make things easier and more natural. Add const
where possible and convenient.
Change-Id: Id5ab5339c3eb6432e809ad14782952d6a45806f3
Approved-By: Pedro Alves <pedro@palves.net>
Reviewed-By: Reviewed-By: Lancelot Six <lancelot.six@amd.com>
This function is just a wrapper around the current inferior's gdbarch.
I find that having that wrapper just obscures where the arch is coming
from, and that it's often used as "I don't know which arch to use so
I'll use this magical target_gdbarch function that gets me an arch" when
the arch should in fact come from something in the context (a thread,
objfile, symbol, etc). I think that removing it and inlining
`current_inferior ()->arch ()` everywhere will make it a bit clearer
where that arch comes from and will trigger people into reflecting
whether this is the right place to get the arch or not.
Change-Id: I79f14b4e4934c88f91ca3a3155f5fc3ea2fadf6b
Reviewed-By: John Baldwin <jhb@FreeBSD.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>
The free_objfile observable is never called with a nullptr objfile.
Change-Id: I1e990edeb45bc38009ccb129c623911097ab65fe
Approved-By: Tom Tromey <tom@tromey.com>
This backlink is not necessary, we always know the program space from
the context. Pass it down the solib_unloaded observer.
Change-Id: I45a503472dc791f517558b8141901472634e0556
Approved-By: Tom Tromey <tom@tromey.com>
I found a few spots like:
string_file f;
std::string x = f.string ();
However, string_file::string returns a 'const std::string &'... so it
seems to me that this must be copying the string (? I find it hard to
reason about this in C++).
This patch changes these spots to use release() instead, which moves
the string.
Reviewed-by: Keith Seitz <keiths@redhat.com>
Reviewed-by: Lancelot Six <lancelot.six@amd.com>
This replaces some casts to 'tracepoint *' with checked_static_cast.
Some functions are changed to accept a 'tracepoint *' now, for better
type safety.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
This replaces some casts to 'watchpoint *' with checked_static_cast.
In one spot, an unnecessary block is also removed.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Make sure to unlink the related breakpoint when the watchpoint instance
is deleted. This prevents having a wp-related breakpoint that is
linked to a NULL watchpoint (e.g. the watchpoint instance is being
deleted when the 'watch' command fails). With the below scenario,
having such a left out breakpoint will lead to a GDB hang, and this
is due to an infinite loop when deleting all inferior breakpoints.
Scenario:
(gdb) set can-use-hw-watchpoints 0
(gdb) awatch <SCOPE VAR>
Can't set read/access watchpoint when hardware watchpoints are disabled.
(gdb) rwatch <SCOPE VAR>
Can't set read/access watchpoint when hardware watchpoints are disabled.
(gdb) <continue the program until the end>
>> HANG <<
Signed-off-by: Mohamed Bouhaouel <mohamed.bouhaouel@intel.com>
Reviewed-by: Bruno Larsen <blarsen@redhat.com>
Currently, each target backend is responsible for printing "[Thread
...exited]" before deleting a thread. This leads to unnecessary
differences between targets, like e.g. with the remote target, we
never print such messages, even though we do print "[New Thread ...]".
E.g., debugging the gdb.threads/attach-many-short-lived-threads.exp
with gdbserver, letting it run for a bit, and then pressing Ctrl-C, we
currently see:
(gdb) c
Continuing.
^C[New Thread 3850398.3887449]
[New Thread 3850398.3887500]
[New Thread 3850398.3887551]
[New Thread 3850398.3887602]
[New Thread 3850398.3887653]
...
Thread 1 "attach-many-sho" received signal SIGINT, Interrupt.
0x00007ffff7e6a23f in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0, req=req@entry=0x7fffffffda80, rem=rem@entry=0x7fffffffda80)
at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
78 in ../sysdeps/unix/sysv/linux/clock_nanosleep.c
(gdb)
Above, we only see "New Thread" notifications, even though threads
were deleted.
After this patch, we'll see:
(gdb) c
Continuing.
^C[Thread 3558643.3577053 exited]
[Thread 3558643.3577104 exited]
[Thread 3558643.3577155 exited]
[Thread 3558643.3579603 exited]
...
[New Thread 3558643.3597415]
[New Thread 3558643.3600015]
[New Thread 3558643.3599965]
...
Thread 1 "attach-many-sho" received signal SIGINT, Interrupt.
0x00007ffff7e6a23f in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0, req=req@entry=0x7fffffffda80, rem=rem@entry=0x7fffffffda80)
at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
78 in ../sysdeps/unix/sysv/linux/clock_nanosleep.c
(gdb) q
This commit fixes this by moving the thread exit printing to common
code instead, triggered from within delete_thread (or rather,
set_thread_exited).
There's one wrinkle, though. While most targest want to print:
[Thread ... exited]
the Windows target wants to print:
[Thread ... exited with code <exit_code>]
... and sometimes wants to suppress the notification for the main
thread. To address that, this commits adds a delete_thread_with_code
function, only used by that target (so far).
This fix was originally posted as part of a larger series:
https://inbox.sourceware.org/gdb-patches/20221212203101.1034916-1-pedro@palves.net/
But didn't really need to be part of that series. In order to get
this fix merged sooner, I (Andrew Burgess) have rebased this commit
outside of the original series. Any bugs introduced while splitting
this patch out and rebasing, are entirely my own.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30129
Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
The commit:
commit b080fe54fb
Date: Tue Nov 8 12:32:51 2022 +0000
gdb: add inferior-specific breakpoints
introduced a bug in the function breakpoint_set_inferior. The above
commit includes this line:
gdb::observers::breakpoint_modified.notify (b);
when it should have instead used this line:
notify_breakpoint_modified (b);
The change to use notify_breakpoint_modified was introduced to GDB
after commit b080fe54fb was written, but before it was merged, and I
failed to update this part of the code during the rebase.
The consequence of this error is that the MI interpreter will not emit
breakpoint-modified notifications when breakpoint_set_inferior is
called.
In this commit I update the code to call notify_breakpoint_modified,
and add a test that checks the MI events are being emitted correctly
in this case.
This commit extends the breakpoint mechanism to allow for inferior
specific breakpoints (but not watchpoints in this commit).
As GDB gains better support for multiple connections, and so for
running multiple (possibly unrelated) inferiors, then it is not hard
to imagine that a user might wish to create breakpoints that apply to
any thread in a single inferior. To achieve this currently, the user
would need to create a condition possibly making use of the $_inferior
convenience variable, which, though functional, isn't the most user
friendly.
This commit adds a new 'inferior' keyword that allows for the creation
of inferior specific breakpoints.
Inferior specific breakpoints are automatically deleted when the
associated inferior is removed from GDB, this is similar to how
thread-specific breakpoints are deleted when the associated thread is
deleted.
Watchpoints are already per-program-space, which in most cases mean
watchpoints are already inferior specific. There is a small window
where inferior-specific watchpoints might make sense, which is after a
vfork, when two processes are sharing the same address space.
However, I'm leaving that as an exercise for another day. For now,
attempting to use the inferior keyword with a watchpoint will give an
error, like this:
(gdb) watch a8 inferior 1
Cannot use 'inferior' keyword with watchpoints
A final note on the implementation: currently, inferior specific
breakpoints, like thread-specific breakpoints, are inserted into every
inferior, GDB then checks once the inferior stops if we are in the
correct thread or inferior, and resumes automatically if we stopped in
the wrong thread/inferior.
An obvious optimisation here is to only insert breakpoint locations
into the specific program space (which mostly means inferior) that
contains either the inferior or thread we are interested in. This
would reduce the number times GDB has to stop and then resume again in
a multi-inferior setup.
I have a series on the mailing list[1] that implements this
optimisation for thread-specific breakpoints. Once this series has
landed I'll update that series to also handle inferior specific
breakpoints in the same way. For now, inferior specific breakpoints
are just slightly less optimal, but this is no different to
thread-specific breakpoints in a multi-inferior debug session, so I
don't see this as a huge problem.
[1] https://inbox.sourceware.org/gdb-patches/cover.1685479504.git.aburgess@redhat.com/
Add new commands:
set debug breakpoint on|off
show debug breakpoint
This patch introduces new debugging information that prints
breakpoint location insertion and removal flow.
The debug output looks like:
~~~
(gdb) set debug breakpoint on
(gdb) disassemble main
Dump of assembler code for function main:
0x0000555555555129 <+0>: endbr64
0x000055555555512d <+4>: push %rbp
0x000055555555512e <+5>: mov %rsp,%rbp
=> 0x0000555555555131 <+8>: mov $0x0,%eax
0x0000555555555136 <+13>: pop %rbp
0x0000555555555137 <+14>: ret
End of assembler dump.
(gdb) break *0x0000555555555137
Breakpoint 2 at 0x555555555137: file main.c, line 4.
[breakpoint] update_global_location_list: insert_mode = UGLL_MAY_INSERT
(gdb) c
Continuing.
[breakpoint] update_global_location_list: insert_mode = UGLL_INSERT
[breakpoint] insert_bp_location: Breakpoint 2 (0x5565daddb1e0) at address 0x555555555137 in main at main.c:4
[breakpoint] insert_bp_location: Breakpoint -2 (0x5565dab51c10) at address 0x7ffff7fd37b5
[breakpoint] insert_bp_location: Breakpoint -5 (0x5565dab68f30) at address 0x7ffff7fe509e
[breakpoint] insert_bp_location: Breakpoint -7 (0x5565dab694f0) at address 0x7ffff7fe63f4
[breakpoint] remove_breakpoint_1: Breakpoint 2 (0x5565daddb1e0) at address 0x555555555137 in main at main.c:4 due to regular remove
[breakpoint] remove_breakpoint_1: Breakpoint -2 (0x5565dab51c10) at address 0x7ffff7fd37b5 due to regular remove
[breakpoint] remove_breakpoint_1: Breakpoint -5 (0x5565dab68f30) at address 0x7ffff7fe509e due to regular remove
[breakpoint] remove_breakpoint_1: Breakpoint -7 (0x5565dab694f0) at address 0x7ffff7fe63f4 due to regular remove
Breakpoint 2, 0x0000555555555137 in main () at main.c:4
4 }
~~~
Co-Authored-By: Christina Schimpe <christina.schimpe@intel.com>
This commit replaces this earlier commit:
commit 2e411b8c68
Date: Fri Oct 14 14:53:15 2022 +0100
gdb: don't always print breakpoint location after failed condition check
and is a result of feedback received here[1].
The original commit addressed a problem where, if a breakpoint
condition included an inferior function call, and if the inferior
function call failed, then GDB would announce the stop twice. Here's
an example of GDB's output before the above commit that shows the
problem being addressed:
(gdb) break foo if (some_func ())
Breakpoint 1 at 0x40111e: file bpcond.c, line 11.
(gdb) r
Starting program: /tmp/bpcond
Program received signal SIGSEGV, Segmentation fault.
0x0000000000401116 in some_func () at bpcond.c:5
5 return *p;
Error in testing condition for breakpoint 1:
The program being debugged stopped while in a function called from GDB.
Evaluation of the expression containing the function
(some_func) will be abandoned.
When the function is done executing, GDB will silently stop.
Breakpoint 1, 0x0000000000401116 in some_func () at bpcond.c:5
5 return *p;
(gdb)
The original commit addressed this issue in breakpoint.c, by spotting
that the $pc had changed while evaluating the breakpoint condition,
and inferring from this that GDB must have stopped elsewhere.
However, the way in which the original commit suppressed the second
stop announcement was to set bpstat::print to true -- this tells GDB
not to print the frame during the stop announcement, and for the CLI
this is fine, however, it was pointed out that for the MI this still
isn't really enough. Below is an example from an MI session after the
above commit was applied, this shows the problem with the above
commit:
-break-insert -c "cond_fail()" foo
^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000040111e",func="foo",file="/tmp/mi-condbreak-fail.c",line="30",thread-groups=["i1"],cond="cond_fail()",times="0",original-location="foo"}
(gdb)
-exec-run
=thread-group-started,id="i1",pid="2636270"
=thread-created,id="1",group-id="i1"
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1",ranges=[{from="0x00007ffff7fd3110",to="0x00007ffff7ff2bb4"}]
^running
*running,thread-id="all"
(gdb)
=library-loaded,id="/lib64/libm.so.6",target-name="/lib64/libm.so.6",host-name="/lib64/libm.so.6",symbols-loaded="0",thread-group="i1",ranges=[{from="0x00007ffff7e59390",to="0x00007ffff7ef4f98"}]
=library-loaded,id="/lib64/libc.so.6",target-name="/lib64/libc.so.6",host-name="/lib64/libc.so.6",symbols-loaded="0",thread-group="i1",ranges=[{from="0x00007ffff7ca66b0",to="0x00007ffff7df3c5f"}]
~"\nProgram"
~" received signal SIGSEGV, Segmentation fault.\n"
~"0x0000000000401116 in cond_fail () at /tmp/mi-condbreak-fail.c:24\n"
~"24\t return *p;\t\t\t/* Crash here. */\n"
*stopped,reason="signal-received",signal-name="SIGSEGV",signal-meaning="Segmentation fault",frame={addr="0x0000000000401116",func="cond_fail",args=[],file="/tmp/mi-condbreak-fail.c",fullname="/tmp/mi-condbreak-fail.c",line="24",arch="i386:x86-64"},thread-id="1",stopped-threads="all",core="9"
&"Error in testing condition for breakpoint 1:\n"
&"The program being debugged was signaled while in a function called from GDB.\n"
&"GDB remains in the frame where the signal was received.\n"
&"To change this behavior use \"set unwindonsignal on\".\n"
&"Evaluation of the expression containing the function\n"
&"(cond_fail) will be abandoned.\n"
&"When the function is done executing, GDB will silently stop.\n"
=breakpoint-modified,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000040111e",func="foo",file="/tmp/mi-condbreak-fail.c",fullname="/tmp/mi-condbreak-fail.c",line="30",thread-groups=["i1"],cond="cond_fail()",times="1",original-location="foo"}
*stopped
(gdb)
Notice that we still see two '*stopped' lines, the first includes the
full frame information, while the second has no frame information,
this is a result of bpstat::print having been set. Ideally, the
second '*stopped' line should not be present.
By setting bpstat::print I was addressing the problem too late, this
flag really only changes how interp::on_normal_stop prints the stop
event, and interp::on_normal_stop is called (indirectly) from the
normal_stop function in infrun.c. A better solution is to avoid
calling normal_stop at all for the stops which should not be reported
to the user, and this is what I do in this commit.
This commit has 3 parts:
1. In breakpoint.c, revert the above commit,
2. In fetch_inferior_event (infrun.c), capture the stop-id before
calling handle_inferior_event. If, after calling
handle_inferior_event, the stop-id has changed, then this indicates
that somewhere within handle_inferior_event, a stop was announced to
the user. If this is the case then GDB should not call normal_stop,
and we should rely on whoever announced the stop to ensure that we
are in a PROMPT_NEEDED state, which means the prompt will be
displayed once fetch_inferior_event returns. And,
3. In infcall.c, do two things:
(a) In run_inferior_call, after making the inferior call, ensure
that either async_disable_stdin or async_enable_stdin is called
to put the prompt state, and stdin handling into the correct
state based on whether the inferior call completed successfully
or not, and
(b) In call_thread_fsm::should_stop, call async_enable_stdin
rather than changing the prompt state directly. This isn't
strictly necessary, but helped me understand this code more.
This async_enable_stdin call is only reached if normal_stop is
not going to be called, and replaces the async_enable_stdin call
that exists in normal_stop. Though we could just adjust the
prompt state if felt (to me) much easier to understand when I
could see this call and the corresponding call in normal_stop.
With these changes in place now, when the inferior call (from the
breakpoint condition) fails, infcall.c leaves the prompt state as
PROMPT_NEEDED, and leaves stdin registered with the event loop.
Back in fetch_inferior_event GDB notices that the stop-id has changed
and so avoids calling normal_stop.
And on return from fetch_inferior_event GDB will display the prompt
and handle input from stdin.
As normal_stop is not called the MI problem is solved, and the test
added in the earlier mentioned commit still passes just fine, so the
CLI has not regressed.
[1] https://inbox.sourceware.org/gdb-patches/6fd4aa13-6003-2563-5841-e80d5a55d59e@palves.net/
This commit improves the output of this previous commit:
commit 2dc3457a45
Date: Fri Oct 14 13:22:55 2022 +0100
gdb: include breakpoint number in testing condition error message
The earlier commit extended the error message:
Error in testing breakpoint condition:
to include the breakpoint number, e.g.:
Error in testing breakpoint condition 3:
This commit extends takes this further, and includes the location
number if the breakpoint has multiple locations, so we might now see:
Error in testing breakpoint condition 3.2:
Just as with how GDB reports a normal breakpoint stop, if a breakpoint
only has a single location then the location number is not included,
this keeps things nice and consistent.
I've extended one of the tests to cover the new functionality.
Approved-By: Pedro Alves <pedro@palves.net>
Remove the breakpoint_pointer_iterator layer. Adjust all users of
all_breakpoints and all_tracepoints to use references instead of
pointers.
Change-Id: I376826f812117cee1e6b199c384a10376973af5d
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Remove the bp_location_pointer_iterator layer. Adjust all users of
breakpoint::locations to use references instead of pointers.
Change-Id: Iceed34f5e0f5790a9cf44736aa658be6d1ba1afa
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
