Enable stdio forwarding when nonstop mode is enabled, and disable it
once it is disabled. This makes it possible to cleanly handle stdio
forwarding while running multiple processes in non-stop mode.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128932
Stop all processes and clear notification queues when disabling non-stop
mode. Ensure that no stop notifications are sent for processes stopped
due to the mode switch.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128893
Fix the response to `?` packet for threads that are running at the time
(in non-stop mode). The previous code would wrongly send or queue
an empty response for them.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128879
Introduce a new %Stdio notification category and use it to send process
output asynchronously when running in non-stop mode. This is an LLDB
extension since GDB does not use the 'O' packet for process output,
just for replies to 'qRcmd' packets.
Using the async notification mechanism implies that only the first
output packet is sent immediately to the client. The client needs
to request subsequent notifications (if any) using the new vStdio packet
(that works pretty much like vStopped for the Stop notification queue).
The packet handler in lldb-server tests is updated to handle the async
stdio packets in addition to the regular O packets. However, due
to the implications noted above, it can only handle the first output
packet sent by the server. Subsequent packets need to be explicitly
requested via vStdio.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128849
Improve handling of multiple successive continue packets in non-stop
mode. More specifically:
1. Explicitly send error response (instead of crashing on assertion)
if the user attempts to resume the same process twice. Since we
do not support thread-level non-stop mode, one needs to always stop
the process explicitly before resuming another thread set.
2. Actually stop the process if "vCont;t" is delivered to a running
process. Similarly, we only support stopping all the running threads
simultaneously (via -1) and return an error in any other case.
With this patch, running multiple processes simultaneously is still
unsupported. The patch also employs a hack to avoid enabling stdio
forwarding on "vCont;t" packet. Both of these issues are addressed
by followup patches.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128710
Improve handling of multiple successive continue packets in non-stop
mode. More specifically:
1. Explicitly send error response (instead of crashing on assertion)
if the user attempts to resume the same process twice. Since we
do not support thread-level non-stop mode, one needs to always stop
the process explicitly before resuming another thread set.
2. Actually stop the process if "vCont;t" is delivered to a running
process. Similarly, we only support stopping all the running threads
simultaneously (via -1) and return an error in any other case.
With this patch, running multiple processes simultaneously is still
unsupported. The patch also employs a hack to avoid enabling stdio
forwarding on "vCont;t" packet. Both of these issues are addressed
by followup patches.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128710
Perform a major refactoring of vCont-threads tests in order to attempt
to improve their stability and performance.
Split test_vCont_run_subset_of_threads() into smaller test cases,
and split the whole suite into two files: one for signal-related tests,
the running-subset-of tests.
Eliminate output_match checks entirely, as they are fragile to
fragmentation of output. Instead, for the initial thread list capture
raise an explicit SIGINT from inside the test program, and for
the remaining output let the test program run until exit, and check all
the captured output afterwards.
For resume tests, capture the LLDB's thread view before and after
starting new threads in order to determine the IDs corresponding
to subthreads rather than relying on program output for that.
Add a mutex for output to guarantee serialization. A barrier is used
to guarantee that all threads start before SIGINT, and an atomic bool
is used to delay prints from happening until after SIGINT.
Call std::this_thread::yield() to reduce the risk of one of the threads
not being run.
This fixes the test hangs on FreeBSD. Hopefully, it will also fix all
the flakiness on buildbots.
Thanks to Pavel Labath for figuring out why the original version did not
work on Debian.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D129012
Using SIGSTOP means that if anything goes wrong in the test, the process
can end up in the stopped state, where it is not running, but still
taking up resources. Eventually, these "zombies" can make the machine
completely unusable. Instead, use a signal whose default action is to
kill the processes.
Perform a major refactoring of vCont-threads tests in order to attempt
to improve their stability and performance.
Split test_vCont_run_subset_of_threads() into smaller test cases,
and split the whole suite into two files: one for signal-related tests,
the running-subset-of tests.
Eliminate output_match checks entirely, as they are fragile to
fragmentation of output. Instead, for the initial thread list capture
raise an explicit SIGSTOP from inside the test program, and for
the remaining output let the test program run until exit, and check all
the captured output afterwards.
For resume tests, capture the LLDB's thread view before and after
starting new threads in order to determine the IDs corresponding
to subthreads rather than relying on program output for that.
Add a mutex for output to guarantee serialization. A barrier is used
to guarantee that all threads start before SIGSTOP, and an atomic bool
is used to delay prints from happening until after SIGSTOP.
Call std::this_thread::yield() to reduce the risk of one of the threads
not being run.
This fixes the test hangs on FreeBSD. Hopefully, it will also fix all
the flakiness on buildbots.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D129012
This recommits b15b1421, which reverted in was reverted in f51c47d98 due to
failures on apple systems. The problem was that the patch introduced a race
where the debug server could start the attach process before the first process
(which isn't supposed to be attached to) was set up. This caused us to attach
to the wrong process.
The new version introduces additional synchronization to ensure that does not
happen.
Original commit message was:
As the documentation states, using this is not safe in multithreaded
programs, and I have traced it to a rare deadlock in some of the tests.
The reason this was introduced was to be able to attach to a program
from the very first instruction, where our usual mechanism of
synchronization -- waiting for a file to appear -- does not work.
However, this is only needed for a single test
(TestGdbRemoteAttachWait) so instead of doing this everywhere, I create
a bespoke solution for that single test. The solution basically
consists of outsourcing the preexec_fn code to a separate (and
single-threaded) shim process, which enables attaching and then executes
the real program.
This pattern could be generalized in case we needed to use it for other
tests, but I suspect that we will not be having many tests like this.
This effectively reverts commit
a997a1d7fb.
As the documentation states, using this is not safe in multithreaded
programs, and I have traced it to a rare deadlock in some of the tests.
The reason this was introduced was to be able to attach to a program
from the very first instruction, where our usual mechanism of
synchronization -- waiting for a file to appear -- does not work.
However, this is only needed for a single test
(TestGdbRemoteAttachWait) so instead of doing this everywhere, I create
a bespoke solution for that single test. The solution basically
consists of outsourcing the preexec_fn code to a separate (and
single-threaded) shim process, which enables attaching and then executes
the real program.
This pattern could be generalized in case we needed to use it for other
tests, but I suspect that we will not be having many tests like this.
This effectively reverts commit
a997a1d7fb.
TestVSCode_breakpointEvents.py is failing on macOS Ventura because we
receive 3 breakpoint events instead of one. This is likely the result of
dyld moving into the shared cache.
Replace the use of "trap" with a new "stop" command in fork tests,
that maps to `raise(SIGSTOP)`. Since traps do not increment PC on some
architectures (notably ARM), using traps would require special logic
to increment it while testing. Using SIGSTOP avoids the problem
and is probably more logical, given that the purpose of the "trap"s
was to simply stop the inferior at a synchronization point. This fixes
tests on AArch64 (and possibly ARM, I'll update XFAILs when it is
confirmed by the buildbot).
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128780
Split the test that's gotten very long in two, in hope that it will
resolve the arm/aarch64 buildbot failures. Even if it does not, it
could help pinpointing where the problem lies.
Sponsored by: The FreeBSD Foundation
Fix lldb-server in the non-stop + multiprocess mode to exit on vStopped
only if all processes have exited, rather than when the first one exits.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128639
Extend the most of baseline fork tests to run in nonstop mode as well.
For more cases, we're just testing one example scenario to save time.
This patch does not cover tests that rely on correct exit handling,
as fixing that is addressed in a followup patch.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128638
Implement support for the "t" action that is used to stop a thread.
Normally this action is used only in non-stop mode. However, there's
no technical reason why it couldn't be also used in all-stop mode,
e.g. to express "resume all threads except ..." (`t:...;c`).
While at it, add a more complete test for vCont correctly resuming
a subset of program's threads.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D126983
Now preserving the non-standard behavior of returning "OK" response
when there is no debugged process.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128152
This reverts part of commit 75757c86c6.
It broke the following test:
commands/target/auto-install-main-executable/TestAutoInstallMainExecutable.py
I need more time to figure it out, so I'm reverting the code changes
and marking the tests depending on them xfail.
Implement the 'T' packet that is used to verify whether the specified
thread belongs to the debugged processes.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128170
Update the `qfThreadInfo` handler to report threads of all debugged
processes and include PIDs when in multiprocess mode.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128152
Extend vCont function to support resuming a process with an arbitrary
PID, that could be different than the one selected via Hc (or no process
at all may be selected). Resuming more than one process simultaneously
is not supported yet.
Remove the ReadTid() method that was only used by Handle_vCont(),
and furthermore it was wrongly using m_current_process rather than
m_continue_process.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D127862
Add a test verifying that it is possible to resume a single process
via the `c` packet when multiple processes are being debugged. This
includes a tiny change to the test program — when `fork()` is called,
the child process is no longer terminated immediately but continues
performing the same tasks as queued for the parent.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D127755
Implement the support for the vKill packet. This is the modern packet
used by the GDB Remote Serial Protocol to kill one of the debugged
processes. Unlike the `k` packet, it has well-defined semantics.
The `vKill` packet takes the PID of the process to kill, and always
replies with an `OK` reply (rather than the exit status, as LLGS does
for `k` packets at the moment). Additionally, unlike the `k` packet
it does not cause the connection to be terminated once the last process
is killed — the client needs to close it explicitly.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D127667
Modify the behavior of the `k` packet to kill all inferiors rather than
just the current one. The specification leaves the exact behavior
of this packet up to the implementation but since vKill is specifically
meant to be used to kill a single process, it seems logical to use `k`
to provide the alternate function of killing all of them.
Move starting stdio forwarding from the "running" response
to the packet handlers that trigger the process to start. This avoids
attempting to start it multiple times when multiple processes are killed
on Linux which implicitly causes LLGS to receive "started" events
for all of them. This is probably also more correct as the ability
to send "O" packets is implied by the continue-like command being issued
(and therefore the client waiting for responses) rather than the start
notification.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D127500
