This callback dynamically allocates a specialized displaced_step_closure, and
gives the ownership of the object to its caller. So I think it would make
sense for the callback to return an std::unique_ptr, this is what this patch
implements.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_copy_insn): Change return type to an
std::unique_ptr.
* gdbarch.c: Re-generate.
* gdbarch.h: Re-generate.
* infrun.c (displaced_step_prepare_throw): Adjust to std::unique_ptr
change.
* aarch64-tdep.c (aarch64_displaced_step_copy_insn): Change return
type to std::unique_ptr.
* aarch64-tdep.h (aarch64_displaced_step_copy_insn): Likewise.
* amd64-tdep.c (amd64_displaced_step_copy_insn): Likewise.
* amd64-tdep.h (amd64_displaced_step_copy_insn): Likewise.
* arm-linux-tdep.c (arm_linux_displaced_step_copy_insn): Likewise.
* i386-linux-tdep.c (i386_linux_displaced_step_copy_insn): Likewise.
* i386-tdep.c (i386_displaced_step_copy_insn): Likewise.
* i386-tdep.h (i386_displaced_step_copy_insn): Likewise.
* rs6000-tdep.c (ppc_displaced_step_copy_insn): Likewise.
* s390-tdep.c (s390_displaced_step_copy_insn): Likewise.
displaced_step_inferior_state::reset and displaced_step_clear appear to
have the same goal, but they don't do the same thing.
displaced_step_inferior_state::reset clears more things than
displaced_step_clear, but it misses free'ing the closure, which
displaced_step_clear does.
This patch replaces displaced_step_clear's implementation with just a call to
displaced_step_inferior_state::reset. It then changes
displaced_step_inferior_state::step_closure to be a unique_ptr, to indicate the
fact that displaced_step_inferior_state owns the closure (and so that it is
automatically freed when the field is reset).
The test gdb.base/step-over-syscall.exp caught a problem when doing this, which
I consider to be a latent bug which my cleanup exposes. In
handle_inferior_event, in the TARGET_WAITKIND_FORKED case, if we displaced-step
over a fork syscall, we make sure to restore the memory that we used as a
displaced-stepping buffer in the child. We do so using the
displaced_step_inferior_state of the parent. However, we do it after calling
displaced_step_fixup for the parent, which clears the information in the
parent's displaced_step_inferior_state. It worked fine before, because
displaced_step_clear didn't completely clear the displaced_step_inferior_state
structure, so the required information (in this case the gdbarch) was
still available after clearing.
I fixed it by making GDB restore the child's memory before calling the
displaced_step_fixup on the parent. This way, the data in the
displaced_step_inferior_state structure is still valid when we use it for the
child. This is the error you would get in
gdb.base/step-over-syscall.exp without this fix:
/home/smarchi/src/binutils-gdb/gdb/gdbarch.c:3911: internal-error: ULONGEST gdbarch_max_insn_length(gdbarch*): Assertion `gdbarch != NULL' failed.
gdb/ChangeLog:
* infrun.c (get_displaced_step_closure_by_addr): Adjust to
std::unique_ptr.
(displaced_step_clear): Rename to...
(displaced_step_reset): ... this. Just call displaced->reset ().
(displaced_step_clear_cleanup): Rename to...
(displaced_step_reset_cleanup): ... this.
(displaced_step_prepare_throw): Adjust to std::unique_ptr.
(displaced_step_fixup): Likewise.
(resume_1): Likewise.
(handle_inferior_event): Restore child's memory before calling
displaced_step_fixup on the parent.
* infrun.h (displaced_step_inferior_state) <reset>: Adjust
to std::unique_ptr.
<step_closure>: Change type to std::unique_ptr.
New in v3:
- Code cleanups based on reviews.
New in v2:
- Fixed misc problems based on reviews.
- Switched to using gdbarch_program_breakpoint_here_p as opposed to
gdbarch_insn_is_breakpoint.
- Fixed matching of brk instructions. Previously the mask was incorrect, which
was showing up as a few failures in the testsuite. Now it is clean.
- New testcase (separate patch).
- Moved program_breakpoint_here () to arch-utils.c and made it the default
implementation of gdbarch_program_breakpoint_here_p.
--
It was reported to me that program breakpoints (permanent ones inserted into
the code itself) other than the one GDB uses for AArch64 (0xd4200000) do not
generate visible stops when continuing, and GDB will continue spinning
infinitely.
This happens because GDB, upon hitting one of those program breakpoints, thinks
the SIGTRAP came from a delayed breakpoint hit...
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x90f
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 14198)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 14198
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
...
... which is not the case.
If the program breakpoint is one GDB recognizes, then it will stop when it
hits it.
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x0
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 14193)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 14193
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14193] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14193.14193.0 [process 14193],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: random signal (GDB_SIGNAL_TRAP)
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: process 14193 not executing
infrun: stop_all_threads, pass=1, iterations=1
infrun: process 14193 not executing
infrun: stop_all_threads done
Program received signal SIGTRAP, Trace/breakpoint trap.
problem_function () at brk_0.c:7
7 asm("brk %0\n\t" ::"n"(0x0));
infrun: infrun_async(0)
Otherwise GDB will keep trying to resume the inferior and will keep
seeing the SIGTRAP's, without stopping.
To the user it appears GDB has gone into an infinite loop, interruptible only
by Ctrl-C.
Also, windbg seems to use a different variation of AArch64 breakpoint compared
to GDB. This causes problems when debugging Windows on ARM binaries, when
program breakpoints are being used.
The proposed patch creates a new gdbarch method (gdbarch_program_breakpoint_here_p)
that tells GDB whether the underlying instruction is a breakpoint instruction
or not.
This is more general than only checking for the instruction GDB uses as
breakpoint.
The existing logic is still preserved for targets that do not implement this
new gdbarch method.
The end result is like so:
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x90f
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 16417)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 16417
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 16417] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 16417.16417.0 [process 16417],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: random signal (GDB_SIGNAL_TRAP)
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: process 16417 not executing
infrun: stop_all_threads, pass=1, iterations=1
infrun: process 16417 not executing
infrun: stop_all_threads done
Program received signal SIGTRAP, Trace/breakpoint trap.
problem_function () at brk.c:7
7 asm("brk %0\n\t" ::"n"(0x900 + 0xf));
infrun: infrun_async(0)
gdb/ChangeLog:
2020-01-29 Luis Machado <luis.machado@linaro.org>
* aarch64-tdep.c (BRK_INSN_MASK): Define to 0xffe0001f.
(BRK_INSN_MASK): Define to 0xd4200000.
(aarch64_program_breakpoint_here_p): New function.
(aarch64_gdbarch_init): Set gdbarch_program_breakpoint_here_p hook.
* arch-utils.c (default_program_breakpoint_here_p): Moved from
breakpoint.c.
* arch-utils.h (default_program_breakpoint_here_p): Moved from
breakpoint.h
* breakpoint.c (bp_loc_is_permanent): Changed return type to bool and
call gdbarch_program_breakpoint_here_p.
(program_breakpoint_here): Moved to arch-utils.c, renamed to
default_program_breakpoint_here_p, changed return type to bool and
simplified.
* breakpoint.h (program_breakpoint_here): Moved prototype to
arch-utils.h, renamed to default_program_breakpoint_here_p and changed
return type to bool.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (program_breakpoint_here_p): New method.
* infrun.c (handle_signal_stop): Call
gdbarch_program_breakpoint_here_p.
This fixes a latent bug exposed by the multi-target patch (5b6d1e4fa
"Multi-target support), and then fixes two other latent bugs exposed
by fixing that first latent bug.
The symptom described in the bug report is that starting a first
inferior, then trying to run a second (multi-threaded) inferior twice,
causes libthread_db to fail to load, along with other erratic
behavior:
(gdb) run
Starting program: /tmp/foo
warning: td_ta_new failed: generic error
Going a bit deeply, I found that if the two inferiors have different
symbols, we can see that just after inferior 2 exits, we are left with
inferior 2 selected, which is correct, but the symbols in scope belong
to inferior 1, which is obviously incorrect...
This problem is that there's a path in
scoped_restore_current_thread::restore() that switches to no thread
selected, and switches the current inferior, but leaves the current
program space as is, resulting in leaving the program space pointing
to the wrong program space (the one of the other inferior). This was
happening after handling TARGET_WAITKIND_NO_RESUMED, which is an event
that triggers after TARGET_WAITKIND_EXITED for the previous inferior
exit. Subsequent symbol lookups find the symbols of the wrong
inferior.
The fix is to use switch_to_inferior_no_thread in that problem spot.
This function was recently added along with the multi-target work
exactly for these situations.
As for testing, this patch adds a new testcase that tests symbol
printing just after inferior exit, which exercises the root cause of
the problem more directly. And then, to cover the use case described
in the bug too, it also exercises the lithread_db.so mis-loading, by
using TLS printing as a proxy for being sure that threaded debugging
was activated sucessfully. The testcase fails without the fix like
this, for the "print symbol just after exit" bits:
...
[Inferior 1 (process 8719) exited normally]
(gdb) PASS: gdb.multi/multi-re-run.exp: re_run_inf=1: iter=1: continue until exit
print re_run_var_1
No symbol "re_run_var_1" in current context.
(gdb) FAIL: gdb.multi/multi-re-run.exp: re_run_inf=1: iter=1: print re_run_var_1
...
And like this for the "libthread_db.so loading" bits:
(gdb) run
Starting program: /home/pedro/gdb/binutils-gdb/build/gdb/testsuite/outputs/gdb.multi/multi-re-run/multi-re-run
warning: td_ta_new failed: generic error
[New LWP 27001]
Thread 1.1 "multi-re-run" hit Breakpoint 3, all_started () at /home/pedro/gdb/binutils-gdb/build/../src/gdb/testsuite/gdb.multi/multi-re-run.c:44
44 }
(gdb) PASS: gdb.multi/multi-re-run.exp: re_run_inf=1: iter=2: running to all_started in runto
print tls_var
Cannot find thread-local storage for LWP 27000, executable file /home/pedro/gdb/binutils-gdb/build/gdb/testsuite/outputs/gdb.multi/multi-re-run/multi-re-run:
Cannot find thread-local variables on this target
(gdb) FAIL: gdb.multi/multi-re-run.exp: re_run_inf=1: iter=2: print tls_var
As mentioned, that fix above goes on to expose a couple other latent
bugs. This commit fixes those as well.
The first latent bug exposed is in
infrun.c:handle_vfork_child_exec_or_exit. The current code is leaving
inf->pspace == NULL while calling clone_program_space. The idea was
to make it so that the breakpoints module doesn't use this inferior's
pspace to set breakpoints. With that, any
scoped_restore_current_thread use from within clone_program_space
tries to restore a NULL program space, which hits an assertion:
Attaching after Thread 0x7ffff74b8700 (LWP 27276) vfork to child process 27277]
[New inferior 2 (process 27277)]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
/home/pedro/gdb/binutils-gdb/build/../src/gdb/progspace.c:243: internal-error: void set_current_program_space(program_space*): Assertion `pspace != NULL' faile
d.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/vfork-follow-child-exit.exp: detach-on-fork=off: continue (GDB internal error)
That NULL pspace idea was legitimate, but it's no longer necessary,
since commit b2e586e850 ("Defer breakpoint reset when cloning
progspace for fork child"). So the fix is to just set the inferior's
program space earlier.
The other latent bug exposed is in exec.c. When exec_close is called
from the program_space destructor, it is purposedly called with a
current program space that is not the current inferior's program
space. The problem is that the multi-target work added some code to
remove_target_sections that loops over all inferiors, and uses
scoped_restore_current_thread to save/restore the previous
thread/inferior/frame state. This makes it so that exec_close returns
with the current program space set to the current inferior's program
space, which is exactly what we did not want. Then the program_space
destructor continues into free_all_objfiles, but it is now running
that method on the wrong program space, resulting in:
Reading symbols from /home/pedro/gdb/binutils-gdb/build/gdb/testsuite/outputs/gdb.threads/fork-plus-threads/fork-plus-threads...
Reading symbols from /usr/lib/debug/usr/lib64/libpthread-2.26.so.debug...
Reading symbols from /usr/lib/debug/usr/lib64/libm-2.26.so.debug...
Reading symbols from /usr/lib/debug/usr/lib64/libc-2.26.so.debug...
Reading symbols from /usr/lib/debug/usr/lib64/ld-2.26.so.debug...
[Inferior 3 (process 9583) exited normally]
/home/pedro/gdb/binutils-gdb/build/../src/gdb/progspace.c:170: internal-error: void program_space::free_all_objfiles(): Assertion `so->objfile == NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: inferior 1 exited (GDB internal error)
The fix is to use scoped_restore_current_pspace_and_thread instead of
scoped_restore_current_thread.
gdb/ChangeLog:
2020-01-24 Pedro Alves <palves@redhat.com>
PR gdb/25410
* thread.c (scoped_restore_current_thread::restore): Use
switch_to_inferior_no_thread.
* exec.c: Include "progspace-and-thread.h".
(add_target_sections, remove_target_sections):
scoped_restore_current_pspace_and_thread instead of
scoped_restore_current_thread.
* infrun.c (handle_vfork_child_exec_or_exit): Assign the pspace
and aspace to the inferior before calling clone_program_space.
Remove stale comment.
gdb/testsuite/ChangeLog:
2020-01-24 Pedro Alves <palves@redhat.com>
PR gdb/25410
* gdb.multi/multi-re-run-1.c: New.
* gdb.multi/multi-re-run-2.c: New.
* gdb.multi/multi-re-run.exp: New.
While doing some investigation of mine, i noticed a few typos,
inaccuracies and missing information.
I went ahead and updated/improved those.
gdb/ChangeLog:
2020-01-14 Luis Machado <luis.machado@linaro.org>
* inf-ptrace.c (inf_ptrace_target::resume): Update comments.
* infrun.c (resume_1): Likewise.
(handle_inferior_event): Remove stale comment.
* linux-nat.c (linux_nat_target::resume): Update comments.
(save_stop_reason): Likewise.
(linux_nat_filter_event): Likewise.
* linux-nat.h (struct lwp_info) <stop_pc>, <stop_reason>: Likewise.
Currently, we can only support resuming multiple targets at the same
time if all targets are in non-stop mode (or user-visible all-stop
mode with target backend in non-stop mode).
This patch makes GDB error out if the user tries to resume more than
one target at the same time and one of the resumed targets isn't in
non-stop mode:
(gdb) info inferiors
Num Description Connection Executable
1 process 15303 1 (native) a.out
* 2 process 15286 2 (extended-remote :9999) a.out
(gdb) set schedule-multiple on
(gdb) c
Continuing.
Connection 2 (extended-remote :9999) does not support multi-target resumption.
This is here later in the series instead of in the main multi-target
patch because it depends the previous patch, which added
process_stratum_target::connection_string().
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* infrun.c: Include "target-connection.h".
(check_multi_target_resumption): New.
(proceed): Call it.
* target-connection.c (make_target_connection_string): Make
extern.
* target-connection.h (make_target_connection_string): Declare.
This commit adds multi-target support to GDB. What this means is that
with this commit, GDB can now be connected to different targets at the
same time. E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.
Actually, the word "target" is overloaded in gdb. We already have a
target stack, with pushes several target_ops instances on top of one
another. We also have "info target" already, which means something
completely different to what this patch does.
So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack. This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously. The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.
User-interface-wise, not that much changes. The main difference is
that each inferior may have its own target connection.
A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.
Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:
(gdb) target extended-remote :9999
...
(gdb) start
...
(gdb) add-inferior
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) file a.out
...
(gdb) start
...
At this point, you have two inferiors connected to the same gdbserver.
With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.
To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior. Same across a fork - the child inherits a copy of the
target stack of the parent. While the target stacks are copied, the
targets themselves are not. Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.
What if you want to create an inferior and connect it to some _other_
target? For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target. So you could do:
(gdb) target extended-remote :9999
Remote debugging using :9999
...
(gdb) add-inferior -no-connection
[New inferior 2]
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 <null>
(gdb) tar extended-remote :10000
Remote debugging using :10000
...
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 process 18450 target:/home/pedro/tmp/main
(gdb)
A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.
Other than that, debugging is the same as before. Users interact with
inferiors and threads as before. The only difference is that
inferiors may be bound to processes running in different machines.
That's pretty much all there is to it in terms of noticeable UI
changes.
On to implementation.
Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier. Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread. Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target. In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects. So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.
Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior. That is done via a
inf->process_target() convenience method.
Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls. The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call. Not relying on global
context is just not feasible in current GDB. Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread. Note, to emphasize -- there's
no method to "switch to this target stack". Instead, you switch the
current inferior, and that implicitly switches the target stack.
In some spots, we need to iterate over all inferiors so that we reach
all target stacks.
Native targets are still singletons. There's always only a single
instance of such targets.
Remote targets however, we'll have one instance per remote connection.
The exec target is still a singleton. There's only one instance. I
did not see the point of instanciating more than one exec_target
object.
After vfork, we need to make sure to push the exec target on the new
inferior. See exec_on_vfork.
For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *. Some shared code in gdb/nat/ also need to
gain a target pointer parameter. This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops. To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense. There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.
The thread and inferior iterator functions also gain
process_stratum_target parameters. These are used to be able to
iterate over threads and inferiors of a given target. Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.
I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec". I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.
In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets. See do_target_wait. Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event. This makes most of the code transparent to
multi-targets. See fetch_inferior_event.
infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets. What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads. Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target. Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor. Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations. This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question. See wait_one / stop_all_threads in infrun.c.
The 'threads_executing' global is made a per-target variable. Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.
You'll notice that remote.c includes some FIXME notes. These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals. For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features. They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program. That isn't going to
work correctly today, because of said globals. I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first. It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.
Current limitations:
- You can only resume more that one target at the same time if all
targets support asynchronous debugging, and support non-stop mode.
It should be possible to support mixed all-stop + non-stop
backends, but that is left for another time. This means that
currently in order to do multi-target with gdbserver you need to
issue "maint set target-non-stop on". I would like to make that
mode be the default, but we're not there yet. Note that I'm
talking about how the target backend works, only. User-visible
all-stop mode works just fine.
- As explained above, connecting to different remote servers at the
same time is likely to produce bad results if they don't support the
exact set of RSP features.
FreeBSD updates courtesy of John Baldwin.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
John Baldwin <jhb@FreeBSD.org>
* aarch64-linux-nat.c
(aarch64_linux_nat_target::thread_architecture): Adjust.
* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
(task_command_1): Likewise.
* aix-thread.c (sync_threadlists, aix_thread_target::resume)
(aix_thread_target::wait, aix_thread_target::fetch_registers)
(aix_thread_target::store_registers)
(aix_thread_target::thread_alive): Adjust.
* amd64-fbsd-tdep.c: Include "inferior.h".
(amd64fbsd_get_thread_local_address): Pass down target.
* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
thread's gdbarch instead of target_gdbarch.
* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
get_last_target_status.
* break-catch-syscall.c (print_it_catch_syscall): Likewise.
* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
inferiors.
(update_inserted_breakpoint_locations): Skip if inferiors with no
execution.
(update_global_location_list): When handling moribund locations,
find representative inferior for location's pspace, and use thread
count of its process_stratum target.
* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
* bsd-uthread.c (bsd_uthread_target::wait): Use
as_process_stratum_target and adjust thread_change_ptid and
add_thread calls.
(bsd_uthread_target::update_thread_list): Use
as_process_stratum_target and adjust find_thread_ptid,
thread_change_ptid and add_thread calls.
* btrace.c (maint_btrace_packet_history_cmd): Adjust
find_thread_ptid call.
* corelow.c (add_to_thread_list): Adjust add_thread call.
(core_target_open): Adjust add_thread_silent and thread_count
calls.
(core_target::pid_to_str): Adjust find_inferior_ptid call.
* ctf.c (ctf_target_open): Adjust add_thread_silent call.
* event-top.c (async_disconnect): Pop targets from all inferiors.
* exec.c (add_target_sections): Push exec target on all inferiors
sharing the program space.
(remove_target_sections): Remove the exec target from all
inferiors sharing the program space.
(exec_on_vfork): New.
* exec.h (exec_on_vfork): Declare.
* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
Pass it down.
(fbsd_nat_target::update_thread_list): Adjust.
(fbsd_nat_target::resume): Adjust.
(fbsd_handle_debug_trap): Add fbsd_nat_target parameter. Pass it
down.
(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
* fbsd-tdep.c (fbsd_corefile_thread): Adjust
get_thread_arch_regcache call.
* fork-child.c (gdb_startup_inferior): Pass target down to
startup_inferior and set_executing.
* gdbthread.h (struct process_stratum_target): Forward declare.
(add_thread, add_thread_silent, add_thread_with_info)
(in_thread_list): Add process_stratum_target parameter.
(find_thread_ptid(inferior*, ptid_t)): New overload.
(find_thread_ptid, thread_change_ptid): Add process_stratum_target
parameter.
(all_threads()): Delete overload.
(all_threads, all_non_exited_threads): Add process_stratum_target
parameter.
(all_threads_safe): Use brace initialization.
(thread_count): Add process_stratum_target parameter.
(set_resumed, set_running, set_stop_requested, set_executing)
(threads_are_executing, finish_thread_state): Add
process_stratum_target parameter.
(switch_to_thread): Use is_current_thread.
* i386-fbsd-tdep.c: Include "inferior.h".
(i386fbsd_get_thread_local_address): Pass down target.
* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
* inf-child.c (inf_child_target::maybe_unpush_target): Remove
have_inferiors check.
* inf-ptrace.c (inf_ptrace_target::create_inferior)
(inf_ptrace_target::attach): Adjust.
* infcall.c (run_inferior_call): Adjust.
* infcmd.c (run_command_1): Pass target to
scoped_finish_thread_state.
(proceed_thread_callback): Skip inferiors with no execution.
(continue_command): Rename 'all_threads' local to avoid hiding
'all_threads' function. Adjust get_last_target_status call.
(prepare_one_step): Adjust set_running call.
(signal_command): Use user_visible_resume_target. Compare thread
pointers instead of inferior_ptid.
(info_program_command): Adjust to pass down target.
(attach_command): Mark target's 'thread_executing' flag.
(stop_current_target_threads_ns): New, factored out from ...
(interrupt_target_1): ... this. Switch inferior before making
target calls.
* inferior-iter.h
(struct all_inferiors_iterator, struct all_inferiors_range)
(struct all_inferiors_safe_range)
(struct all_non_exited_inferiors_range): Filter on
process_stratum_target too. Remove explicit.
* inferior.c (inferior::inferior): Push dummy target on target
stack.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
Add process_stratum_target parameter, and pass it down.
(have_live_inferiors): Adjust.
(switch_to_inferior_and_push_target): New.
(add_inferior_command, clone_inferior_command): Handle
"-no-connection" parameter. Use
switch_to_inferior_and_push_target.
(_initialize_inferior): Mention "-no-connection" option in
the help of "add-inferior" and "clone-inferior" commands.
* inferior.h: Include "process-stratum-target.h".
(interrupt_target_1): Use bool.
(struct inferior) <push_target, unpush_target, target_is_pushed,
find_target_beneath, top_target, process_target, target_at,
m_stack>: New.
(discard_all_inferiors): Delete.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
(all_inferiors, all_non_exited_inferiors): Add
process_stratum_target parameter.
* infrun.c: Include "gdb_select.h" and <unordered_map>.
(target_last_proc_target): New global.
(follow_fork_inferior): Push target on new inferior. Pass target
to add_thread_silent. Call exec_on_vfork. Handle target's
reference count.
(follow_fork): Adjust get_last_target_status call. Also consider
target.
(follow_exec): Push target on new inferior.
(struct execution_control_state) <target>: New field.
(user_visible_resume_target): New.
(do_target_resume): Call target_async.
(resume_1): Set target's threads_executing flag. Consider resume
target.
(commit_resume_all_targets): New.
(proceed): Also consider resume target. Skip threads of inferiors
with no execution. Commit resumtion in all targets.
(start_remote): Pass current inferior to wait_for_inferior.
(infrun_thread_stop_requested): Consider target as well. Pass
thread_info pointer to clear_inline_frame_state instead of ptid.
(infrun_thread_thread_exit): Consider target as well.
(random_pending_event_thread): New inferior parameter. Use it.
(do_target_wait): Rename to ...
(do_target_wait_1): ... this. Add inferior parameter, and pass it
down.
(threads_are_resumed_pending_p, do_target_wait): New.
(prepare_for_detach): Adjust calls.
(wait_for_inferior): New inferior parameter. Handle it. Use
do_target_wait_1 instead of do_target_wait.
(fetch_inferior_event): Adjust. Switch to representative
inferior. Pass target down.
(set_last_target_status): Add process_stratum_target parameter.
Save target in global.
(get_last_target_status): Add process_stratum_target parameter and
handle it.
(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
(context_switch): Check inferior_ptid == null_ptid before calling
inferior_thread().
(get_inferior_stop_soon): Pass down target.
(wait_one): Rename to ...
(poll_one_curr_target): ... this.
(struct wait_one_event): New.
(wait_one): New.
(stop_all_threads): Adjust.
(handle_no_resumed, handle_inferior_event): Adjust to consider the
event's target.
(switch_back_to_stepped_thread): Also consider target.
(print_stop_event): Update.
(normal_stop): Update. Also consider the resume target.
* infrun.h (wait_for_inferior): Remove declaration.
(user_visible_resume_target): New declaration.
(get_last_target_status, set_last_target_status): New
process_stratum_target parameter.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter, and use it.
(clear_inline_frame_state (thread_info*)): New.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter.
(clear_inline_frame_state (thread_info*)): Declare.
* linux-fork.c (delete_checkpoint_command): Pass target down to
find_thread_ptid.
(checkpoint_command): Adjust.
* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
instead of just tweaking inferior_ptid.
(linux_nat_switch_fork): Pass target down to thread_change_ptid.
(exit_lwp): Pass target down to find_thread_ptid.
(attach_proc_task_lwp_callback): Pass target down to
add_thread/set_running/set_executing.
(linux_nat_target::attach): Pass target down to
thread_change_ptid.
(get_detach_signal): Pass target down to find_thread_ptid.
Consider last target status's target.
(linux_resume_one_lwp_throw, resume_lwp)
(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
(linux_nat_target::async_wait_fd): New.
(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
target down.
* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
* linux-tdep.c (get_thread_arch_regcache): Pass target down.
* linux-thread-db.c (struct thread_db_info::process_target): New
field.
(add_thread_db_info): Save target.
(get_thread_db_info): New process_stratum_target parameter. Also
match target.
(delete_thread_db_info): New process_stratum_target parameter.
Also match target.
(thread_from_lwp): Adjust to pass down target.
(thread_db_notice_clone): Pass down target.
(check_thread_db_callback): Pass down target.
(try_thread_db_load_1): Always push the thread_db target.
(try_thread_db_load, record_thread): Pass target down.
(thread_db_target::detach): Pass target down. Always unpush the
thread_db target.
(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
target down. Always unpush the thread_db target.
(find_new_threads_callback, thread_db_find_new_threads_2)
(thread_db_target::update_thread_list): Pass target down.
(thread_db_target::pid_to_str): Pass current inferior down.
(thread_db_target::get_thread_local_address): Pass target down.
(thread_db_target::resume, maintenance_check_libthread_db): Pass
target down.
* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
* procfs.c (procfs_target::procfs_init_inferior): Declare.
(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
(procfs_init_inferior): Rename to ...
(procfs_target::procfs_init_inferior): ... this and adjust.
(procfs_target::create_inferior, procfs_notice_thread)
(procfs_do_thread_registers): Adjust.
* ppc-fbsd-tdep.c: Include "inferior.h".
(ppcfbsd_get_thread_local_address): Pass down target.
* proc-service.c (ps_xfer_memory): Switch current inferior and
program space as well.
(get_ps_regcache): Pass target down.
* process-stratum-target.c
(process_stratum_target::thread_address_space)
(process_stratum_target::thread_architecture): Pass target down.
* process-stratum-target.h
(process_stratum_target::threads_executing): New field.
(as_process_stratum_target): New.
* ravenscar-thread.c
(ravenscar_thread_target::update_inferior_ptid): Pass target down.
(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
down.
* record-btrace.c (record_btrace_target::info_record): Adjust.
(record_btrace_target::record_method)
(record_btrace_target::record_is_replaying)
(record_btrace_target::fetch_registers)
(get_thread_current_frame_id, record_btrace_target::resume)
(record_btrace_target::wait, record_btrace_target::stop): Pass
target down.
* record-full.c (record_full_wait_1): Switch to event thread.
Pass target down.
* regcache.c (regcache::regcache)
(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
process_stratum_target parameter and handle it.
(current_thread_target): New global.
(get_thread_regcache): Add process_stratum_target parameter and
handle it. Switch inferior before calling target method.
(get_thread_regcache): Pass target down.
(get_thread_regcache_for_ptid): Pass target down.
(registers_changed_ptid): Add process_stratum_target parameter and
handle it.
(registers_changed_thread, registers_changed): Pass target down.
(test_get_thread_arch_aspace_regcache): New.
(current_regcache_test): Define a couple local test_target_ops
instances and use them for testing.
(readwrite_regcache): Pass process_stratum_target parameter.
(cooked_read_test, cooked_write_test): Pass mock_target down.
* regcache.h (get_thread_regcache, get_thread_arch_regcache)
(get_thread_arch_aspace_regcache): Add process_stratum_target
parameter.
(regcache::target): New method.
(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
(regcache::registers_changed_ptid): Add process_stratum_target
parameter.
(regcache::m_target): New field.
(registers_changed_ptid): Add process_stratum_target parameter.
* remote.c (remote_state::supports_vCont_probed): New field.
(remote_target::async_wait_fd): New method.
(remote_unpush_and_throw): Add remote_target parameter.
(get_current_remote_target): Adjust.
(remote_target::remote_add_inferior): Push target.
(remote_target::remote_add_thread)
(remote_target::remote_notice_new_inferior)
(get_remote_thread_info): Pass target down.
(remote_target::update_thread_list): Skip threads of inferiors
bound to other targets. (remote_target::close): Don't discard
inferiors. (remote_target::add_current_inferior_and_thread)
(remote_target::process_initial_stop_replies)
(remote_target::start_remote)
(remote_target::remote_serial_quit_handler): Pass down target.
(remote_target::remote_unpush_target): New remote_target
parameter. Unpush the target from all inferiors.
(remote_target::remote_unpush_and_throw): New remote_target
parameter. Pass it down.
(remote_target::open_1): Check whether the current inferior has
execution instead of checking whether any inferior is live. Pass
target down.
(remote_target::remote_detach_1): Pass down target. Use
remote_unpush_target.
(extended_remote_target::attach): Pass down target.
(remote_target::remote_vcont_probe): Set supports_vCont_probed.
(remote_target::append_resumption): Pass down target.
(remote_target::append_pending_thread_resumptions)
(remote_target::remote_resume_with_hc, remote_target::resume)
(remote_target::commit_resume): Pass down target.
(remote_target::remote_stop_ns): Check supports_vCont_probed.
(remote_target::interrupt_query)
(remote_target::remove_new_fork_children)
(remote_target::check_pending_events_prevent_wildcard_vcont)
(remote_target::remote_parse_stop_reply)
(remote_target::process_stop_reply): Pass down target.
(first_remote_resumed_thread): New remote_target parameter. Pass
it down.
(remote_target::wait_as): Pass down target.
(unpush_and_perror): New remote_target parameter. Pass it down.
(remote_target::readchar, remote_target::remote_serial_write)
(remote_target::getpkt_or_notif_sane_1)
(remote_target::kill_new_fork_children, remote_target::kill): Pass
down target.
(remote_target::mourn_inferior): Pass down target. Use
remote_unpush_target.
(remote_target::core_of_thread)
(remote_target::remote_btrace_maybe_reopen): Pass down target.
(remote_target::pid_to_exec_file)
(remote_target::thread_handle_to_thread_info): Pass down target.
(remote_target::async_wait_fd): New.
* riscv-fbsd-tdep.c: Include "inferior.h".
(riscv_fbsd_get_thread_local_address): Pass down target.
* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
Adjust.
* solib-spu.c (spu_skip_standalone_loader): Pass down target.
* solib-svr4.c (enable_break): Pass down target.
* spu-multiarch.c (parse_spufs_run): Pass down target.
* spu-tdep.c (spu2ppu_sniffer): Pass down target.
* target-delegates.c: Regenerate.
* target.c (g_target_stack): Delete.
(current_top_target): Return the current inferior's top target.
(target_has_execution_1): Refer to the passed-in inferior's top
target.
(target_supports_terminal_ours): Check whether the initial
inferior was already created.
(decref_target): New.
(target_stack::push): Incref/decref the target.
(push_target, push_target, unpush_target): Adjust.
(target_stack::unpush): Defref target.
(target_is_pushed): Return bool. Adjust to refer to the current
inferior's target stack.
(dispose_inferior): Delete, and inline parts ...
(target_preopen): ... here. Only dispose of the current inferior.
(target_detach): Hold strong target reference while detaching.
Pass target down.
(target_thread_name): Add assertion.
(target_resume): Pass down target.
(target_ops::beneath, find_target_at): Adjust to refer to the
current inferior's target stack.
(get_dummy_target): New.
(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
has a thread running.
(initialize_targets): Rename to ...
(_initialize_target): ... this.
* target.h: Include "gdbsupport/refcounted-object.h".
(struct target_ops): Inherit refcounted_object.
(target_ops::shortname, target_ops::longname): Make const.
(target_ops::async_wait_fd): New method.
(decref_target): Declare.
(struct target_ops_ref_policy): New.
(target_ops_ref): New typedef.
(get_dummy_target): Declare function.
(target_is_pushed): Return bool.
* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
(all_matching_threads_iterator::all_matching_threads_iterator):
Handle filter target.
* thread-iter.h (struct all_matching_threads_iterator, struct
all_matching_threads_range, class all_non_exited_threads_range):
Filter by target too. Remove explicit.
* thread.c (threads_executing): Delete.
(inferior_thread): Pass down current inferior.
(clear_thread_inferior_resources): Pass down thread pointer
instead of ptid_t.
(add_thread_silent, add_thread_with_info, add_thread): Add
process_stratum_target parameter. Use it for thread and inferior
searches.
(is_current_thread): New.
(thread_info::deletable): Use it.
(find_thread_ptid, thread_count, in_thread_list)
(thread_change_ptid, set_resumed, set_running): New
process_stratum_target parameter. Pass it down.
(set_executing): New process_stratum_target parameter. Pass it
down. Adjust reference to 'threads_executing'.
(threads_are_executing): New process_stratum_target parameter.
Adjust reference to 'threads_executing'.
(set_stop_requested, finish_thread_state): New
process_stratum_target parameter. Pass it down.
(switch_to_thread): Also match inferior.
(switch_to_thread): New process_stratum_target parameter. Pass it
down.
(update_threads_executing): Reimplement.
* top.c (quit_force): Pop targets from all inferior.
(gdb_init): Don't call initialize_targets.
* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
Declare.
(windows_add_thread, windows_delete_thread): Adjust.
(get_windows_debug_event): Rename to ...
(windows_nat_target::get_windows_debug_event): ... this. Adjust.
* tracefile-tfile.c (tfile_target_open): Pass down target.
* gdbsupport/common-gdbthread.h (struct process_stratum_target):
Forward declare.
(switch_to_thread): Add process_stratum_target parameter.
* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
parameter. Use it.
(mi_on_resume): Pass target down.
* nat/fork-inferior.c (startup_inferior): Add
process_stratum_target parameter. Pass it down.
* nat/fork-inferior.h (startup_inferior): Add
process_stratum_target parameter.
* python/py-threadevent.c (py_get_event_thread): Pass target down.
gdb/gdbserver/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* fork-child.c (post_fork_inferior): Pass target down to
startup_inferior.
* inferiors.c (switch_to_thread): Add process_stratum_target
parameter.
* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
* nto-low.c (nto_target_ops): Now a process_stratum_target.
* linux-low.c (linux_target_ops): Now a process_stratum_target.
* remote-utils.c (prepare_resume_reply): Pass the target to
switch_to_thread.
* target.c (the_target): Now a process_stratum_target.
(done_accessing_memory): Pass the target to switch_to_thread.
(set_target_ops): Ajust to use process_stratum_target.
* target.h (struct target_ops): Rename to ...
(struct process_stratum_target): ... this.
(the_target, set_target_ops): Adjust.
(prepare_to_access_memory): Adjust comment.
* win32-low.c (child_xfer_memory): Adjust to use
process_stratum_target.
(win32_target_ops): Now a process_stratum_target.
- Make get_last_target_status arguments optional. A following patch
will add another argument to get_last_target_status (the event's
target), and passing nullptr when we don't care for some piece of
info is handier than creating dummy local variables.
- Declare nullify_last_target_wait_ptid in a header, and remove the
local extern declaration from linux-fork.c.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* break-catch-sig.c (signal_catchpoint_print_it): Don't pass a
ptid to get_last_target_status.
* break-catch-syscall.c (print_it_catch_syscall): Don't pass a
ptid to get_last_target_status.
* infcmd.c (continue_command): Don't pass a target_waitstatus to
get_last_target_status.
(info_program_command): Don't pass a target_waitstatus to
get_last_target_status.
* infrun.c (init_wait_for_inferior): Use
nullify_last_target_wait_ptid.
(get_last_target_status): Handle nullptr arguments.
(nullify_last_target_wait_ptid): Clear target_last_waitstatus.
(print_stop_event): Don't pass a ptid to get_last_target_status.
(normal_stop): Don't pass a ptid to get_last_target_status.
* infrun.h (get_last_target_status, set_last_target_status): Move
comments here and update.
(nullify_last_target_wait_ptid): Declare.
* linux-fork.c (fork_load_infrun_state): Remove local extern
declaration of nullify_last_target_wait_ptid.
* linux-nat.c (get_detach_signal): Don't pass a target_waitstatus
to get_last_target_status.
Once each inferior has its own target stack, we'll need to make sure
that the right inferior is selected before we call into target
methods.
It kind of sounds worse than it is in practice. Not that many places
need to be concerned.
In thread.c, we add a new switch_to_thread_if_alive function that
centralizes the switching before calls to target_thread_alive. Other
cases are handled with explicit switching.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* gdbthread.h (scoped_restore_current_thread)
<dont_restore, restore, m_dont_restore>: Declare.
* thread.c (thread_alive): Add assertion. Return bool.
(switch_to_thread_if_alive): New.
(prune_threads): Switch inferior/thread.
(print_thread_info_1): Switch thread before calling target methods.
(scoped_restore_current_thread::restore): New, factored out from
...
(scoped_restore_current_thread::~scoped_restore_current_thread):
... this.
(scoped_restore_current_thread::scoped_restore_current_thread):
Add assertion.
(thread_apply_all_command, thread_select): Use
switch_to_thread_if_alive.
* infrun.c (proceed, restart_threads, handle_signal_stop)
(switch_back_to_stepped_thread): Switch current thread before
calling target methods.
In non-stop mode, if you resume the program in the background (with
"continue&", for example), then gdb makes sure to not switch the
current thread behind your back. That means that you can be sure that
the commands you type apply to the thread you selected, even if some
other thread that was running in the background hits some event just
while you're typing.
In all-stop mode, however, if you resume the program in the
background, gdb let's the current thread switch behind your back.
This is bogus, of course. All-stop and non-stop background
resumptions should behave the same.
This patch fixes that, and adds a testcase that exposes the bad
behavior in current master.
The fork-running-state.exp changes are necessary because that
preexisting testcase was expecting the old behavior:
Before:
continue &
Continuing.
(gdb)
[Attaching after process 8199 fork to child process 8203]
[New inferior 2 (process 8203)]
info threads
Id Target Id Frame
1.1 process 8199 "fork-running-st" (running)
* 2.1 process 8203 "fork-running-st" (running)
(gdb)
After:
continue &
Continuing.
(gdb)
[Attaching after process 24660 fork to child process 24664]
[New inferior 2 (process 24664)]
info threads
Id Target Id Frame
* 1.1 process 24660 "fork-running-st" (running)
2.1 process 24664 "fork-running-st" (running)
(gdb)
Here we see that before this patch GDB switches current inferior to
the new inferior behind the user's back, as a side effect of handling
the fork.
The delete_exited_threads call in inferior_appeared is there to fix an
issue that Baris found in a previous version of this patch. The
fetch_inferior_event change increases the refcount of the current
thread, and in case the fetched inferior event denotes a thread exit,
the thread will not be deleted right away. A non-deleted but exited
thread stays in the inferior's thread list. This, in turn, causes the
"init_thread_list" call in inferior.c to be skipped. A consequence is
that the global thread ID counter is not restarted if the current
thread exits, and then the inferior is restarted:
(gdb) start
Temporary breakpoint 1 at 0x4004d6: file main.c, line 21.
Starting program: /tmp/main
Temporary breakpoint 1, main () at main.c:21
21 foo ();
(gdb) info threads -gid
Id GId Target Id Frame
* 1 1 process 16106 "main" main () at main.c:21
(gdb) c
Continuing.
[Inferior 1 (process 16106) exited normally]
(gdb) start
Temporary breakpoint 2 at 0x4004d6: file main.c, line 21.
Starting program: /tmp/main
Temporary breakpoint 2, main () at main.c:21
21 foo ();
(gdb) info threads -gid
Id GId Target Id Frame
* 1 2 process 16138 "main" main () at main.c:21
^^^
Notice that GId == 2 above. It should have been "1" instead.
The new tids-git-reset.exp testcase exercises the problem above.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* gdbthread.h (scoped_restore_current_thread)
<dont_restore, restore, m_dont_restore>: Declare.
* thread.c (thread_alive): Add assertion. Return bool.
(switch_to_thread_if_alive): New.
(prune_threads): Switch inferior/thread.
(print_thread_info_1): Switch thread before calling target methods.
(scoped_restore_current_thread::restore): New, factored out from
...
(scoped_restore_current_thread::~scoped_restore_current_thread):
... this.
(scoped_restore_current_thread::scoped_restore_current_thread):
Add assertion.
(thread_apply_all_command, thread_select): Use
switch_to_thread_if_alive.
gdb/testsuite/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* gdb.base/fork-running-state.exp (do_test): Adjust expected
output.
* gdb.threads/async.c: New.
* gdb.threads/async.exp: New.
* gdb.multi/tids-gid-reset.c: New.
* gdb.multi/tids-gid-reset.exp: New.
This makes the skip command work in optimized builds, where skipped
functions may be inlined. Previously that was only working when
stepping into a non-inlined function.
While debugging something, i noticed this odd FIXME comment. It seems stale
and therefore here's a patch removing it.
gdb/ChangeLog:
2019-12-02 Luis Machado <luis.machado@linaro.org>
* infrun.c (follow_fork_inferior): Remove outdated FIXME comment.
Change-Id: I2436ca4ae4a6741012cafe8123325f738b692c9c
This changes various spots in gdb to use the new %p format suffixes.
gdb/ChangeLog
2019-10-01 Pedro Alves <palves@redhat.com>
Tom Tromey <tom@tromey.com>
* symtab.c (print_symbol_info): Use %ps.
(print_msymbol_info): Use %ps.
* symfile.c (symbol_file_add_with_addrs): Use %ps.
* printcmd.c (print_variable_and_value): Use %ps.
* macrocmd.c (show_pp_source_pos): Use %ps.
* infrun.c (print_exited_reason): Use ui_out::message.
* breakpoint.c (watchpoint_check, print_one_breakpoint_location)
(describe_other_breakpoints): Use ui_out::message and new
formats.
(say_where): Use new formats.
(bkpt_print_it, tracepoint_print_one_detail): Use ui_out::message
and new formats.
I recently noticed the following behavior while debugging
dw2-ranges-func-low-cold. This is one of the test programs associated
with the test gdb.dwarf2/dw2-ranges-func.exp.
(gdb) b 70
Breakpoint 1 at 0x401129: file dw2-ranges-func-lo-cold.c, line 70.
(gdb) run
Starting program: dw2-ranges-func-lo-cold
Breakpoint 1, foo ()
at dw2-ranges-func-lo-cold.c:70
70 if (e) foo_cold (); /* foo foo_cold call */
(gdb) set var e=1
(gdb) step
[Inferior 1 (process 12545) exited normally]
This is incorrect. When stepping, we expect a step to occur. We do not
expect the program to exit. Instead, we should see the following behavior:
...
(gdb) set var e=1
(gdb) step
foo ()
at dw2-ranges-func-lo-cold.c:54
54 baz (); /* foo_cold baz call */
(Note that I've shortened the paths in the above sessions to improve
readability.)
The bug is in fill_in_stop_func() in infrun.c. While working on
non-contiguous address range improvements in 2018, I replaced the
call to find_pc_partial_function() with a call to
find_function_entry_range_from_pc(). Although this seemed like the
right thing to do at the time, I now think that calling
find_pc_partial_function (along with some other tweaks) is the right
thing to do.
For blocks with a single contiguous range, these functions do pretty
much the same thing: when the function succeeds, the function name,
start address, and end address are all filled in. Additionally,
find_pc_partial_function contains an additional output parameter
which is set to the block containing that PC.
For blocks with non-contiguous ranges, find_pc_partial_function
sets the start and end addresses to the start and end addresses
of the range containing the pc. find_function_entry_range_from_pc
does what it says; it sets the start and end addresses to those
of the range containing the entry pc.
The reason that I had thought that using the entry pc range was
correct is due to the fact that fill_in_stop_func() contains some
code for advancing past the function start and entry point. To do
this, we'd need the range that contains the entry pc.
However, when stepping, we actually want the range that contains the
stop pc. If that range also contains the entry pc, we should then
attempt to advance stop_func_start past the start offset and entry
point. (I haven't thought very hard about the reason for advancing
the stop_func_start in this manner. Since it's been there for quite
a while, I'm assuming that it's still a good idea.)
Back when I wrote the test case, I had included a test for doing the
step shown in the example above. I had problems with it, however. At
the time, I thought it was due to differing compiler versions, so I
disabled that portion of the test. I have now reenabled those tests,
but have left in place the logic which may be used to disable it.
The changes to dw2-ranges-func.exp depend on my other recent changes
to the file which have not been pushed yet.
Finally, I'll note that the only caller of
find_function_entry_range_from_pc() is/was fill_in_stop_func(). Once
this commit goes in, it'll be dead code. I considered removing it,
but I think that it ought to be used (instead of
find_pc_partial_function) for determining the correct range to scan
for prologue analysis, so I'm going to leave it in place for now.
gdb/ChangeLog:
* infrun.c (fill_in_stop_func): Use find_pc_partial_function
instead of find_function_entry_range_from_pc.
testsuite/ChangeLog:
* gdb.dwarf2/dw2-ranges-func.exp (enable_foo_cold_stepping):
Enable tests associated with this flag. Adjust regex
referencing "foo_low" to now refer to "foo_cold" instead.
This replaces uses of field_fmt with a "%s" format string to use
field_string instead. Also, one use of "%9lx" is replaced with a call
to phex_nz; the '9' is dropped as it is implicit in the field width.
2019-07-15 Tom Tromey <tromey@adacore.com>
* mi/mi-main.c (list_available_thread_groups): Use field_string.
* mi/mi-interp.c (mi_memory_changed): Use field_string.
* target.c (flash_erase_command): Use field_string.
* infrun.c (print_signal_received_reason): Use field_string.
* i386-tdep.c (i386_mpx_print_bounds): Use field_string.
* breakpoint.c (maybe_print_thread_hit_breakpoint): Use
field_string.
* ada-tasks.c (print_ada_task_info): Use field_string.
I noticed that target_ops::follow_exec took a "char *" parameter,
where "const char *" would be more correct. This patch changes this
(and related functions) to be constified.
Tested by rebuilding.
gdb/ChangeLog
2019-05-22 Tom Tromey <tromey@adacore.com>
* target.c (target_follow_exec): Constify parameter.
* target-delegates.c: Rebuild.
* remote.c (remote_target::follow_exec): Constify parameter.
* infrun.c (follow_exec): Constify parameter.
* target.h (struct target_ops) <follow_exec>: Constify parameter.
(target_follow_exec): Likewise.
When debugging any of the testcases added by this commit, which do a
vfork in a thread with "set follow-fork-mode child" + "set
detach-on-fork on", we run into this assertion:
...
src/gdb/nat/x86-linux-dregs.c:146: internal-error: \
void x86_linux_update_debug_registers(lwp_info*): \
Assertion `lwp_is_stopped (lwp)' failed.
...
The assert is caused by the following: the vfork-child exit or exec
event is handled by handle_vfork_child_exec_or_exit, which calls
target_detach to detach from the vfork parent. During target_detach
we call linux_nat_target::detach, which:
#1 - stops all the threads
#2 - waits for all the threads to be stopped
#3 - detaches all the threads
However, during the second step we run into this code in
stop_wait_callback:
...
/* If this is a vfork parent, bail out, it is not going to report
any SIGSTOP until the vfork is done with. */
if (inf->vfork_child != NULL)
return 0;
...
and we don't wait for the threads to be stopped, which results in this
assert in x86_linux_update_debug_registers triggering during the third
step:
...
gdb_assert (lwp_is_stopped (lwp));
...
The fix is to reset the vfork parent's vfork_child field before
calling target_detach in handle_vfork_child_exec_or_exit. There's
already similar code for the other paths handled by
handle_vfork_child_exec_or_exit, so this commit refactors the code a
bit so that all paths share the same code.
The new tests cover both a vfork child exiting, and a vfork child
execing, since both cases would trigger the assertion.
The new testcases also exercise following the vfork children with "set
detach-on-fork off", since it doesn't seem to be tested anywhere.
Tested on x86_64-linux, using native and native-gdbserver.
gdb/ChangeLog:
2019-04-18 Tom de Vries <tdevries@suse.de>
Pedro Alves <palves@redhat.com>
PR gdb/24454
* infrun.c (handle_vfork_child_exec_or_exit): Reset vfork parent's
vfork_child field before calling target_detach.
gdb/testsuite/ChangeLog:
2019-04-18 Tom de Vries <tdevries@suse.de>
Pedro Alves <palves@redhat.com>
PR gdb/24454
* gdb.threads/vfork-follow-child-exec.c: New file.
* gdb.threads/vfork-follow-child-exec.exp: New file.
* gdb.threads/vfork-follow-child-exit.c: New file.
* gdb.threads/vfork-follow-child-exit.exp: New file.
This rewrites gdb's TRY/CATCH to plain C++ try/catch. The patch was
largely written by script, though one change (to a comment in
common-exceptions.h) was reverted by hand.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c: Use C++ exception handling.
* x86-linux-nat.c: Use C++ exception handling.
* windows-nat.c: Use C++ exception handling.
* varobj.c: Use C++ exception handling.
* value.c: Use C++ exception handling.
* valprint.c: Use C++ exception handling.
* valops.c: Use C++ exception handling.
* unittests/parse-connection-spec-selftests.c: Use C++ exception
handling.
* unittests/cli-utils-selftests.c: Use C++ exception handling.
* typeprint.c: Use C++ exception handling.
* tui/tui.c: Use C++ exception handling.
* tracefile-tfile.c: Use C++ exception handling.
* top.c: Use C++ exception handling.
* thread.c: Use C++ exception handling.
* target.c: Use C++ exception handling.
* symmisc.c: Use C++ exception handling.
* symfile-mem.c: Use C++ exception handling.
* stack.c: Use C++ exception handling.
* sparc64-linux-tdep.c: Use C++ exception handling.
* solib.c: Use C++ exception handling.
* solib-svr4.c: Use C++ exception handling.
* solib-spu.c: Use C++ exception handling.
* solib-frv.c: Use C++ exception handling.
* solib-dsbt.c: Use C++ exception handling.
* selftest-arch.c: Use C++ exception handling.
* s390-tdep.c: Use C++ exception handling.
* rust-lang.c: Use C++ exception handling.
* rust-exp.y: Use C++ exception handling.
* rs6000-tdep.c: Use C++ exception handling.
* rs6000-aix-tdep.c: Use C++ exception handling.
* riscv-tdep.c: Use C++ exception handling.
* remote.c: Use C++ exception handling.
* remote-fileio.c: Use C++ exception handling.
* record-full.c: Use C++ exception handling.
* record-btrace.c: Use C++ exception handling.
* python/python.c: Use C++ exception handling.
* python/py-value.c: Use C++ exception handling.
* python/py-utils.c: Use C++ exception handling.
* python/py-unwind.c: Use C++ exception handling.
* python/py-type.c: Use C++ exception handling.
* python/py-symbol.c: Use C++ exception handling.
* python/py-record.c: Use C++ exception handling.
* python/py-record-btrace.c: Use C++ exception handling.
* python/py-progspace.c: Use C++ exception handling.
* python/py-prettyprint.c: Use C++ exception handling.
* python/py-param.c: Use C++ exception handling.
* python/py-objfile.c: Use C++ exception handling.
* python/py-linetable.c: Use C++ exception handling.
* python/py-lazy-string.c: Use C++ exception handling.
* python/py-infthread.c: Use C++ exception handling.
* python/py-inferior.c: Use C++ exception handling.
* python/py-gdb-readline.c: Use C++ exception handling.
* python/py-framefilter.c: Use C++ exception handling.
* python/py-frame.c: Use C++ exception handling.
* python/py-finishbreakpoint.c: Use C++ exception handling.
* python/py-cmd.c: Use C++ exception handling.
* python/py-breakpoint.c: Use C++ exception handling.
* python/py-arch.c: Use C++ exception handling.
* printcmd.c: Use C++ exception handling.
* ppc-linux-tdep.c: Use C++ exception handling.
* parse.c: Use C++ exception handling.
* p-valprint.c: Use C++ exception handling.
* objc-lang.c: Use C++ exception handling.
* mi/mi-main.c: Use C++ exception handling.
* mi/mi-interp.c: Use C++ exception handling.
* mi/mi-cmd-stack.c: Use C++ exception handling.
* mi/mi-cmd-break.c: Use C++ exception handling.
* main.c: Use C++ exception handling.
* linux-thread-db.c: Use C++ exception handling.
* linux-tdep.c: Use C++ exception handling.
* linux-nat.c: Use C++ exception handling.
* linux-fork.c: Use C++ exception handling.
* linespec.c: Use C++ exception handling.
* language.c: Use C++ exception handling.
* jit.c: Use C++ exception handling.
* infrun.c: Use C++ exception handling.
* infcmd.c: Use C++ exception handling.
* infcall.c: Use C++ exception handling.
* inf-loop.c: Use C++ exception handling.
* i386-tdep.c: Use C++ exception handling.
* i386-linux-tdep.c: Use C++ exception handling.
* guile/scm-value.c: Use C++ exception handling.
* guile/scm-type.c: Use C++ exception handling.
* guile/scm-symtab.c: Use C++ exception handling.
* guile/scm-symbol.c: Use C++ exception handling.
* guile/scm-pretty-print.c: Use C++ exception handling.
* guile/scm-ports.c: Use C++ exception handling.
* guile/scm-param.c: Use C++ exception handling.
* guile/scm-math.c: Use C++ exception handling.
* guile/scm-lazy-string.c: Use C++ exception handling.
* guile/scm-frame.c: Use C++ exception handling.
* guile/scm-disasm.c: Use C++ exception handling.
* guile/scm-cmd.c: Use C++ exception handling.
* guile/scm-breakpoint.c: Use C++ exception handling.
* guile/scm-block.c: Use C++ exception handling.
* guile/guile-internal.h: Use C++ exception handling.
* gnu-v3-abi.c: Use C++ exception handling.
* gdbtypes.c: Use C++ exception handling.
* frame.c: Use C++ exception handling.
* frame-unwind.c: Use C++ exception handling.
* fbsd-tdep.c: Use C++ exception handling.
* f-valprint.c: Use C++ exception handling.
* exec.c: Use C++ exception handling.
* event-top.c: Use C++ exception handling.
* event-loop.c: Use C++ exception handling.
* eval.c: Use C++ exception handling.
* dwarf2read.c: Use C++ exception handling.
* dwarf2loc.c: Use C++ exception handling.
* dwarf2-frame.c: Use C++ exception handling.
* dwarf2-frame-tailcall.c: Use C++ exception handling.
* dwarf-index-write.c: Use C++ exception handling.
* dwarf-index-cache.c: Use C++ exception handling.
* dtrace-probe.c: Use C++ exception handling.
* disasm-selftests.c: Use C++ exception handling.
* darwin-nat.c: Use C++ exception handling.
* cp-valprint.c: Use C++ exception handling.
* cp-support.c: Use C++ exception handling.
* cp-abi.c: Use C++ exception handling.
* corelow.c: Use C++ exception handling.
* completer.c: Use C++ exception handling.
* compile/compile-object-run.c: Use C++ exception handling.
* compile/compile-object-load.c: Use C++ exception handling.
* compile/compile-cplus-symbols.c: Use C++ exception handling.
* compile/compile-c-symbols.c: Use C++ exception handling.
* common/selftest.c: Use C++ exception handling.
* common/new-op.c: Use C++ exception handling.
* cli/cli-script.c: Use C++ exception handling.
* cli/cli-interp.c: Use C++ exception handling.
* cli/cli-cmds.c: Use C++ exception handling.
* c-varobj.c: Use C++ exception handling.
* btrace.c: Use C++ exception handling.
* breakpoint.c: Use C++ exception handling.
* break-catch-throw.c: Use C++ exception handling.
* arch-utils.c: Use C++ exception handling.
* amd64-tdep.c: Use C++ exception handling.
* ada-valprint.c: Use C++ exception handling.
* ada-typeprint.c: Use C++ exception handling.
* ada-lang.c: Use C++ exception handling.
* aarch64-tdep.c: Use C++ exception handling.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c: Use C++ exception handling.
* linux-low.c: Use C++ exception handling.
* gdbreplay.c: Use C++ exception handling.
The test gdb.threads/watchthreads-reorder.exp verifies that the
'set debug infrun 1' debug output does not crash GDB.
Under high load, the test can still cause a GDB internal error (see details
below).
This patch fixes this crash, and improves/factorises some wait kind traces.
Tested on debian/amd64 + run one test with 'set debug infrun 1'.
Changes compared to the first version:
* Handles the suggestions of Kevin to trace the relevant elements
of the wait status (this is done by calling target_waitstatus_to_string).
* Some other changes to factorise wait status tracing.
Note that using target_waitstatus_to_string instead of the 'locally printed'
status kind strings means that debug trace that was using strings such as:
"EXITED" or "TARGET_WAITKIND_EXITED"
will now use what is printed by target_waitstatus_to_string e.g.
"exited".
gdb/ChangeLog
2019-04-01 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* infrun.c (stop_all_threads): If debug_infrun, always
trace the wait status after wait_one, using
target_waitstatus_to_string and target_pid_to_str.
(handle_inferior_event): Replace various trace of
wait status kind by a single trace.
* gdb/gnu-nat.c (gnu_nat_target::wait): Replace local
wait status kind image by target_waitstatus_to_string.
* target/waitstatus.c (target_waitstatus_to_string): Fix
obsolete comment.
(top-gdb) bt
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1 0x00007f3d54a0642a in __GI_abort () at abort.c:89
#2 0x0000555c24c60e66 in dump_core () at ../../fixleaks/gdb/utils.c:201
#3 0x0000555c24c63d49 in internal_vproblem(internal_problem *, const char *, int, const char *, typedef __va_list_tag __va_list_tag *) (problem=problem@entry=0x555c25338d40 <internal_error_problem>, file=<optimized out>, line=287,
fmt=<optimized out>, ap=<optimized out>) at ../../fixleaks/gdb/utils.c:411
#4 0x0000555c24c63eab in internal_verror (file=<optimized out>, line=<optimized out>, fmt=<optimized out>,
ap=<optimized out>) at ../../fixleaks/gdb/utils.c:436
#5 0x0000555c249e8c22 in internal_error (file=file@entry=0x555c24e0f2ad "../../fixleaks/gdb/inferior.c",
line=line@entry=287, fmt=<optimized out>) at ../../fixleaks/gdb/common/errors.c:55
#6 0x0000555c247d3f5c in find_inferior_pid (pid=<optimized out>) at ../../fixleaks/gdb/inferior.c:287
#7 0x0000555c24ad2248 in find_inferior_pid (pid=<optimized out>) at ../../fixleaks/gdb/inferior.c:302
#8 find_inferior_ptid (ptid=...) at ../../fixleaks/gdb/inferior.c:301
#9 0x0000555c24c35f25 in find_thread_ptid (ptid=...) at ../../fixleaks/gdb/thread.c:522
#10 0x0000555c24b0ab4d in thread_db_target::pid_to_str[abi:cxx11](ptid_t) (
this=0x555c2532e3e0 <the_thread_db_target>, ptid=...) at ../../fixleaks/gdb/linux-thread-db.c:1637
#11 0x0000555c24c2f420 in target_pid_to_str[abi:cxx11](ptid_t) (ptid=...) at ../../fixleaks/gdb/target.c:2083
#12 0x0000555c24ad9cab in stop_all_threads () at ../../fixleaks/gdb/infrun.c:4373
#13 0x0000555c24ada00f in stop_waiting (ecs=<optimized out>) at ../../fixleaks/gdb/infrun.c:7464
#14 0x0000555c24adc401 in process_event_stop_test (ecs=ecs@entry=0x7ffc9402d9d0) at ../../fixleaks/gdb/infrun.c:6181
...
(top-gdb) fr 12
#12 0x0000555c24ad9cab in stop_all_threads () at ../../fixleaks/gdb/infrun.c:4373
(top-gdb) p event_ptid
$5 = {m_pid = 25419, m_lwp = 25427, m_tid = 0}
(top-gdb) p ptid
$6 = {m_pid = 0, m_lwp = 0, m_tid = 0}
(top-gdb) p ws
$7 = {kind = TARGET_WAITKIND_THREAD_EXITED, value = {integer = 0, sig = GDB_SIGNAL_0, related_pid = {m_pid = 0,
m_lwp = 0, m_tid = 0}, execd_pathname = 0x0, syscall_number = 0}}
(top-gdb)
The gdb.log corresponding to the above crash is:
(gdb) PASS: gdb.threads/watchthreads-reorder.exp: reorder1: set debug infrun 1
continue
Continuing.
infrun: clear_proceed_status_thread (Thread 0x7ffff7fcfb40 (LWP 25419))
infrun: clear_proceed_status_thread (Thread 0x7ffff7310700 (LWP 25427))
infrun: clear_proceed_status_thread (Thread 0x7ffff6b0f700 (LWP 25428))
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming Thread 0x7ffff7fcfb40 (LWP 25419)
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff7fcfb40 (LWP 25419)] at 0x7ffff7344317
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: proceed: resuming Thread 0x7ffff7310700 (LWP 25427)
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff7310700 (LWP 25427)] at 0x5555555553d7
infrun: prepare_to_wait
infrun: proceed: resuming Thread 0x7ffff6b0f700 (LWP 25428)
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff6b0f700 (LWP 25428)] at 0x5555555554c8
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
Joining the threads.
[Thread 0x7ffff6b0f700 (LWP 25428) exited]
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: 25419.25419.0 [Thread 0x7ffff7fcfb40 (LWP 25419)],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x555555555e50
infrun: context switch
infrun: Switching context from Thread 0x7ffff6b0f700 (LWP 25428) to Thread 0x7ffff7fcfb40 (LWP 25419)
infrun: BPSTAT_WHAT_STOP_NOISY
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: Thread 0x7ffff7fcfb40 (LWP 25419) not executing
infrun: Thread 0x7ffff7310700 (LWP 25427) executing, need stop
[Thread 0x7ffff7310700 (LWP 25427) exited]
infrun: target_wait (-1.0.0, status) =
infrun: 25419.25427.0 [LWP 25427],
infrun: status->kind = thread exited, status = 0
infrun: infrun_async(0)
../../fixleaks/gdb/inferior.c:287: internal-error: inferior* find_inferior_pid(int): Assertion `pid != 0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/watchthreads-reorder.exp: reorder1: continue to breakpoint: break-at-exit (GDB internal error)
Resyncing due to internal error.
n
infrun: infrun_async(1)
This is a bug, please report it. For instructions, see:
<http://www.gnu.org/software/gdb/bugs/>.
infrun: infrun_async(0)
../../fixleaks/gdb/inferior.c:287: internal-error: inferior* find_inferior_pid(int): Assertion `pid != 0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Create a core file of GDB? (y or n) y
When running under valgrind, multi-arch-exec.exp blocks forever.
Some (painful) investigation shows this is due to valgrind slowing
down GDB, and GDB has to output some messages at a different time,
when GDB does not have the terminal for output.
To reproduce the problem, you need to slow down GDB.
It can be reproduced by:
cd gdb/testsuite/outputs/gdb.multi/multi-arch-exec/
../../../../gdb -ex 'set debug lin-lwp 1' -ex 'break all_started' -ex 'run' ./2-multi-arch-exec
The above stops at a breakpoint. Do continue.
GDB is then suspended because of SIGTTOU.
The stacktrace that leads to the hanging GDB is:
(top-gdb) bt
at ../../binutils-gdb/gdb/exceptions.c:130
....
Alternatively, the same happens when doing
strace -o s.out ../../../../gdb -ex 'break all_started' -ex 'run' ./2-multi-arch-exec
And of course, valgrind is also sufficiently slowing down GDB to
reproduce this :).
Fix this by calling target_terminal::ours_for_output ();
at the beginning of follow_exec.
Note that all this terminal handling is not very clear to me:
* Some code takes the terminal, and then takes care to give it back to the inferior
if the terminal was belonging to the inferior.
(e.g. annotate_breakpoints_invalid).
* some code takes the terminal, but does not give it back
(e.g. update_inserted_breakpoint_locations).
* some code takes it, and unconditionally gives it back
(e.g. handle_jit_event)
* here and there, we also find
gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
before a (sometimes optional) call to ours_for_output.
And such calls to ours_for_output is sometimes protected by:
if (target_supports_terminal_ours ())
(e.g. exceptions.c: print_flush).
but most of the code calls it without checking if the target supports it.
* some code is outputting some errors, but only takes the terminal
after. E.g. infcmd.c: prepare_one_step
gdb/ChangeLog
2019-03-28 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* infrun.c (follow_exec): Call target_terminal::ours_for_output.
I noticed that handle_inferior_event is just a small wrapper that
frees the value chain. This patch replaces it with a
scoped_value_mark, reducing the number of lines of code here.
Regression tested on x86-64 Fedora 29.
gdb/ChangeLog
2019-03-20 Tom Tromey <tromey@adacore.com>
* infrun.c (handle_inferior_event): Rename from
handle_inferior_event_1. Create a scoped_value_mark.
(handle_inferior_event): Remove.
If you run "gdb -i=mi2" and set a "display", then when "next"ing the
displays will be shown twice:
~"1: x = 23\n"
~"7\t printf(\"%d\\n\", x);\n"
~"1: x = 23\n"
*stopped,reason="end-stepping-range",frame={addr="0x0000000000400565",func="main",args=[],file="q.c",fullname="/tmp/q.c",line="7"},thread-id="1",stopped-threads="all",core="1"
The immediate cause of this is this code in mi_on_normal_stop_1:
print_stop_event (mi_uiout);
console_interp = interp_lookup (current_ui, INTERP_CONSOLE);
if (should_print_stop_to_console (console_interp, tp))
print_stop_event (mi->cli_uiout);
... which obviously prints the stop twice.
However, I think the first call to print_stop_event is intended just
to emit the MI *stopped notification, which explains why the source
line does not show up two times.
This patch fixes the bug by changing print_stop_event to only call
do_displays for non-MI-like ui-outs.
Tested on x86-64 Fedora 29.
gdb/ChangeLog
2019-03-19 Tom Tromey <tromey@adacore.com>
* mi/mi-interp.c (mi_on_normal_stop_1): Only show displays once.
* infrun.h (print_stop_event): Add "displays" parameter.
* infrun.c (print_stop_event): Add "displays" parameter.
gdb/testsuite/ChangeLog
2019-03-19 Tom Tromey <tromey@adacore.com>
* gdb.mi/mi2-cli-display.c: New file.
* gdb.mi/mi2-cli-display.exp: New file.
TARGET_WAITKIND_NO_RESUMED doesn't have an associated event thread, so
we shouldn't be referring to inferior_thread() assuming it points to
one.
This was caught on the multi-target branch, where we always switch to
no-thread-selected whenever we start handling an event, exactly to
catch places that incorrectly use "inferior_ptid/inferior_thread()"
without switching to the right event thread / target.
Here, on the branch, we assert in inferior_thread() because
TARGET_WAITKIND_NO_RESUMED doesn't have an associated event thread, so
inferior_ptid is still null_ptid.
gdb/ChangeLog:
2019-03-07 Pedro Alves <palves@redhat.com>
* infrun.c (normal_stop): Also check for
TARGET_WAITKIND_NO_RESUMED before referring to inferior_thread().
This changes displaced_step_clear_cleanup to be a forward_scope_exit
and updates the callers.
gdb/ChangeLog
2019-03-06 Tom Tromey <tom@tromey.com>
* infrun.c (displaced_step_clear_cleanup): Now a
forward_scope_exit type.
(displaced_step_prepare_throw): Update.
(displaced_step_fixup): Update.
A customer noticed some mildly odd MI output, where CLI output was
split into multiple MI strings at unusual boundaries, like this:
~"$1 = (b => true"
~", p => 0x407260"
This is technically correct according to the MI spec, but still
unusual, in that there's no particular reason for the string to be
split where it is.
I tracked this down to a call to gdb_flush in generic_val_print.
Then, I went through all calls to gdb_flush and removed the ones I
thought were superfluous. In particular:
* Any call in the value-printing code;
* Likewise the type-printing code (just a single call); and
* Any call that immediately followed a printf that obviously
ended with a newline, my belief being that gdb's standard output
streams are line buffered (by inheriting the behavior from stdio)
Regression tested on x86-64 Fedora 29.
I didn't add a new test case. I tend to think we don't necessarily
want to specify this behavior in the tests. Let me know what you
think of this.
gdb/ChangeLog
2019-03-05 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat_target::attach)
(windows_nat_target::detach): Don't call gdb_flush.
* valprint.c (generic_val_print, val_print, val_print_string):
Don't call gdb_flush.
* utils.c (defaulted_query): Don't call gdb_flush.
* typeprint.c (print_type_scalar): Don't call gdb_flush.
* target.c (target_announce_detach): Don't call gdb_flush.
* sparc64-tdep.c (adi_print_versions): Don't call gdb_flush.
* remote.c (extended_remote_target::attach): Don't call
gdb_flush.
* procfs.c (procfs_target::detach): Don't call gdb_flush.
* printcmd.c (do_examine): Don't call gdb_flush.
(info_display_command): Don't call gdb_flush.
* p-valprint.c (pascal_val_print): Don't call gdb_flush.
* nto-procfs.c (nto_procfs_target::attach): Don't call gdb_flush.
* memattr.c (info_mem_command): Don't call gdb_flush.
* mdebugread.c (mdebug_build_psymtabs): Don't call gdb_flush.
* m2-valprint.c (m2_val_print): Don't call gdb_flush.
* infrun.c (follow_exec, handle_command): Don't call gdb_flush.
* inf-ptrace.c (inf_ptrace_target::attach): Don't call gdb_flush.
* hppa-tdep.c (unwind_command): Don't call gdb_flush.
* gnu-nat.c (gnu_nat_target::attach): Don't call gdb_flush.
(gnu_nat_target::detach): Don't call gdb_flush.
* f-valprint.c (f_val_print): Don't call gdb_flush.
* darwin-nat.c (darwin_nat_target::attach): Don't call gdb_flush.
* cli/cli-script.c (read_command_lines): Don't call gdb_flush.
* cli/cli-cmds.c (shell_escape, print_disassembly): Don't call
gdb_flush.
* c-valprint.c (c_val_print): Don't call gdb_flush.
* ada-valprint.c (ada_print_scalar): Don't call gdb_flush.
This replaces the pointer and length parameters of target_pass_signals
and target_program_signals with a gdb::array_view parameter, and fixes
the fallout.
In infrun.c, the signal_stop, signal_print, signal_program,
signal_catch, signal_pass globals are currently pointers to
heap-allocated memory. I see no point in that, so I converted them to
arrays. This allows simplifying the calls to
target_pass_signals/target_program_signals, since we can pass the
array directly, which can implicitly convert to gdb::array_view.
gdb/ChangeLog:
2019-01-24 Pedro Alves <palves@redhat.com>
* infrun.c (signal_stop, signal_print, signal_program)
(signal_catch, signal_pass): Now arrays instead of pointers.
(update_signals_program_target, do_target_resume)
(signal_catch_update, handle_command, _initialize_infrun): Adjust.
* linux-nat.c (linux_nat_target::pass_signals)
(linux_nat_target::create_inferior, linux_nat_target::attach):
Adjust.
* linux-nat.h (linux_nat_target::pass_signals): Adjust.
* nto-procfs.c (nto_procfs_target::pass_signals): Adjust.
* procfs.c (procfs_target::pass_signals): Adjust.
* record-full.c (record_full_target::resume): Adjust.
* remote.c (remote_target::pass_signals)
(remote_target::program_signals): Adjust.
* target-debug.h (target_debug_print_signals): Now takes a
gdb::array_view as parameter. Adjust.
* target.h (target_ops) <pass_signals, program_signals>: Replace
pointer and length parameters with gdb::array_view.
(target_pass_signals, target_program_signals): Likewise.
* target-delegates.c: Regenerate.
This updates a comment in fetch_inferior_event. The comment refers to
a cleanup that is now a scoped_restore_current_thread.
gdb/ChangeLog:
2019-01-23 Tom Tromey <tom@tromey.com>
* infrun.c (fetch_inferior_event): Update comment.
This removes the remaining cleanup from fetch_inferior_event,
replacing it with a SCOPE_EXIT. This required introducing a new scope
and reindenting.
gdb/ChangeLog:
2019-01-23 Tom Tromey <tom@tromey.com>
Pedro Alves <palves@redhat.com>
* infrun.c (reinstall_readline_callback_handler_cleanup): Remove
parameter.
(fetch_inferior_event): Use SCOPE_EXIT.
This removes the cleanup from stop_all_threads, replacing it with a
scope_exit.
gdb/ChangeLog:
2019-01-23 Tom Tromey <tom@tromey.com>
Pedro Alves <palves@redhat.com>
* infrun.c (disable_thread_events): Delete.
(stop_all_threads): Use SCOPE_EXIT.
This removes make_bpstat_clear_actions_cleanup, replacing it with uses
of scope_exit.
gdb/ChangeLog:
2019-01-23 Tom Tromey <tom@tromey.com>
Andrew Burgess <andrew.burgess@embecosm.com>
Pedro Alves <palves@redhat.com>
* infrun.c (fetch_inferior_event): Use scope_exit.
* utils.h (make_bpstat_clear_actions_cleanup): Don't declare.
* top.c (execute_command): Use scope_exit.
* breakpoint.c (bpstat_do_actions): Use scope_exit.
* utils.c (do_bpstat_clear_actions_cleanup)
(make_bpstat_clear_actions_cleanup): Remove.
v3: sorted earlier in the series, and replaces the cleanup in
fetch_inferior_event here too instead of in some other patch.
This removes delete_just_stopped_threads_infrun_breakpoints_cleanup,
replacing it with uses of scope_exit.
gdb/ChangeLog:
2019-01-23 Tom Tromey <tom@tromey.com>
Pedro Alves <palves@redhat.com>
* infrun.c: Include "common/scope-exit.h"
(delete_just_stopped_threads_infrun_breakpoints_cleanup): Remove.
(wait_for_inferior): Use SCOPE_EXIT.
(fetch_inferior_event): Use scope_exit.
This patch moves the per-inferior data related to displaced stepping to
be directly in the inferior structure, rather than in a container on the
side.
On notable difference is that previously, we deleted the state on
inferior exit, which guaranteed a clean state if re-using the inferior
for a new run or attach. We now need to reset the state manually.
At the same time, I changed step_saved_copy to be a gdb::byte_vector, so
it is automatically freed on destruction (which should plug the leak
reported here [1]).
[1] https://sourceware.org/ml/gdb-patches/2018-11/msg00202.html
gdb/ChangeLog:
* inferior.h (class inferior) <displaced_step_state>: New field.
* infrun.h (struct displaced_step_state): Move here from
infrun.c. Initialize fields, add constructor.
<inf>: Remove field.
<reset>: New method.
* infrun.c (struct displaced_step_inferior_state): Move to
infrun.h.
(displaced_step_inferior_states): Remove.
(get_displaced_stepping_state): Adust.
(displaced_step_in_progress_any_inferior): Adjust.
(displaced_step_in_progress_thread): Adjust.
(displaced_step_in_progress): Adjust.
(add_displaced_stepping_state): Remove.
(get_displaced_step_closure_by_addr): Adjust.
(remove_displaced_stepping_state): Remove.
(infrun_inferior_exit): Call displaced_step_state.reset.
(use_displaced_stepping): Don't check for NULL.
(displaced_step_prepare_throw): Call
get_displaced_stepping_state.
(displaced_step_fixup): Don't check for NULL.
(prepare_for_detach): Don't check for NULL.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
I ran into a situation where attempting to make an inferior function
call would trigger an assertion, like this:
(gdb) call some_inferior_function ()
../../src/gdb/regcache.c:310: internal-error: void regcache::restore(readonly_detached_regcache*): Assertion `src != NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
The problem that triggers the assertion is that in the function
save_infcall_suspend_state, we basically did this:
1. Create empty infcall_suspend_state object.
2. Fill fields of infcall_suspend_state object.
The problem is causes is that if filling any of the fields triggered
an exception then the infcall_suspend_state object would be deleted
while in a partially filled in state.
In the specific case I encountered, I had a remote RISC-V target that
claimed in its target description to support floating point registers.
However, this was not true, and when GDB tried to read a floating
point register the remote sent back an error. This error would cause
an exception to be thrown while creating the
readonly_detached_regcache, which in turn caused GDB to try and delete
an infcall_suspend_state which didn't have any register state, and
this triggered the assertion.
To prevent this problem we have two possibilities, either, rewrite the
restore code the handle partially initialised infcall_suspend_state
objects, or, prevent partially initialised infcall_suspend_state
objects from existing. The second of these seems like a better
solution.
So, in this patch, I move the filling in of the different
infcall_suspend_state fields within a new constructor for
infcall_suspend_state. Now, if generating one of those fields fails
the destructor for infcall_suspend_state will not be executed and GDB
will not try to restore the partially saved state.
With this patch in place GDB now behaves like this:
(gdb) call some_inferior_function ()
Could not fetch register "ft0"; remote failure reply 'E99'
(gdb)
The inferior function call is aborted due to the error.
This has been tested against x86-64/Linux native, native-gdbserver,
and native-extended-gdbserver with no regressions. I've manually
tested this against my baddly behaving target and confirmed the
inferior function call is aborted as described above.
gdb/ChangeLog:
* infrun.c (infcall_suspend_state::infcall_suspend_state): New.
(infcall_suspend_state::registers): New.
(infcall_suspend_state::restore): New.
(infcall_suspend_state::thread_suspend): Rename to...
(infcall_suspend_state::m_thread_suspend): ...this.
(infcall_suspend_state::registers): Rename to...
(infcall_suspend_state::m_registers): ...this.
(infcall_suspend_state::siginfo_gdbarch): Rename to...
(infcall_suspend_state::m_siginfo_gdbarch): ...this.
(infcall_suspend_state::siginfo_data): Rename to...
(infcall_suspend_state::m_siginfo_data): ...this.
(save_infcall_suspend_state): Rewrite to use infcall_suspend_state
constructor.
(restore_infcall_suspend_state): Rewrite to use
infcall_suspend_state::restore method.
(get_infcall_suspend_state_regcache): Use
infcall_suspend_state::registers method.
Simon Marchi
Luis Machado
Pedro Alves
Joel Brobecker
Bernd Edlinger
Christian Biesinger
Simon Marchi
Tom de Vries
Kevin Buettner
Tom Tromey
Tom Tromey
Philippe Waroquiers
Simon Marchi
Andrew Burgess