Summary:
There was an issue in NPL, where we attempted removal of temporary breakpoints (used to implement
software single stepping), while some threads of the process were running. This is a problem
since we currently always use the main thread's ID in the removal ptrace call. Therefore, if the
main thread was still running, the ptrace call would fail, and the software breakpoint would
remain, causing all kinds of problems. This change removes the breakpoints after all threads have
stopped. This fixes TestExitDuringStep on Android arm and can also potentially help in other
situations, as previously the breakpoint would not get removed if the thread stopped for another
reason.
Test Plan: TestExitDuringStep passes, other tests remain unchanged.
Reviewers: tberghammer
Subscribers: tberghammer, aemerson, lldb-commits
Differential Revision: http://reviews.llvm.org/D9792
llvm-svn: 237448
Summary:
This is the same issue as we had in D9145 for thread creation. Going through the full
ThreadDidStop/RequestResume cycle can cause a deferred notification to fire, which is not correct
when we are ignoring an event and resuming the thread. In this case it doesn't matter much since
the thread will die after that anyway, but for correctness, we should do the same thing here.
Also treating the SIGTRAP case the same way.
Test Plan: Tests continue to pass.
Reviewers: chaoren, ovyalov
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9696
llvm-svn: 237445
Summary:
NPL::Resume attempted to handle eStateStopped as a resume action. However:
- GDBRemoteCommunicationServerLLGS (the only user of NPL) never sets this action
- it could set this action in response to a vCont:t packet, but LLDB never produces this packet
- gdb-remote protocol documentation says vCont:t packet is used only in non-stop mode, but LLDB
does not support non-stop mode
- even if LLDB supported non-stop mode, this implementation of eStateStopped does something
different from what the spec says it should (according to spec, it should stop the specified
thread, but this seems to want to stop all threads).
Given the facts above, I believe we should remove this unused and untested code, as it probably
doesn't even work and removing it makes the rest of the code noticably simpler.
Reviewers: ovyalov, chaoren
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9657
llvm-svn: 237103
Summary:
Since the former-TSC events are now processed synchronously, there is no need for to protect them
with a separate mutex - all the actions are now guarded by the big m_threads_mutex.
With the mutex gone, the following functions, no longer have any purpose and were removed:
NotifyThreadCreate: replaced by direct calls to ThreadWasCreated
NotifyThreadStop: replaced by direct calls to ThreadDidStop
NotifyThreadDeath: folded into StopTrackingThread
ResetForExec: inlined as it consisted of a single line of code
RequestThreadResume(AsNeeded): replaced by direct calls to ResumeThread
StopThreads: removed, as it was never called
Test Plan: tests continue to pass
Reviewers: ovyalov, chaoren
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9603
llvm-svn: 237101
Summary:
Now that all thread events are processed synchronously, there is no need to have separate records
of whether a thread is running. This changes the (ever-dwindling) remains of the TSC to use
NativeThreadLinux as the authoritative source of the state of threads. The rest of the
ThreadContext we need has been moved to a member of NTL.
Test Plan: ninja check-lldb continues to pass
Reviewers: chaoren, ovyalov
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9562
llvm-svn: 236983
Summary:
The stop callback is a remnant of the ThreadStateCoordinator. We don't need it now that TSC is
gone, as we know exactly which function to call when threads stop. This also removes some
stop-related functions, which were just forwarding calls to one another.
Test Plan: ninja check-lldb continues to pass
Reviewers: chaoren, ovyalov
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9531
llvm-svn: 236814
Summary:
These are remnants of the thread state coordinator, which are now unnecessary. I have basically
inlined the callbacks. No functional change.
Test Plan: Tests continue to pass.
Reviewers: chaoren, vharron
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9343
llvm-svn: 236707
Summary:
The lambda was always calling SetState(eStateStopped) with small variations, so I have inlined
the code. Given that we don't have the TSC anymore, I believe we don't need to be so generic.
The only major change here is the way we choose a stop reason thread when we're interrupting a
program on client request. Previously, we were setting a null stop reason for all threads and
then fixing up the reason for one victim thread in the lambda. Now, I make sure the stop reason
is set for the victim thread correctly in the first place.
I also take the opportunity to rename CallAfter* functions into something more appropriate.
Test Plan: All tests continue to pass.
Reviewers: chaoren, vharron
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9321
llvm-svn: 236595
Summary:
Since all TSC operations are now executed synchronously, TSC has become a little more than a
messenger between different parts of NativeProcessLinux. Therefore, the reason for its existance
has disappeared.
This commit moves the contents of the TSC into the NPL class. This will enable us to remove all
the boilerplate code in NPL (as it stands now, this is most of the class), which I plan to do in
subsequent commits.
Unfortunately, this also means we will lose the unit tests for the TSC. However, since the size
of the TSC has diminished, the unit tests were not testing much at this point anyway, so it's not
a big loss.
No functional change.
Test Plan: All tests continue to pass.
Reviewers: vharron, chaoren
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9296
llvm-svn: 236587
Summary:
This change removes the thread state coordinator thread by making all the operations it was
performing synchronous. In order to prevent deadlock, NativeProcessLinux must now always call
m_monitor->DoOperation with the m_threads_mutex released. This is needed because HandleWait
callbacks lock the mutex (which means the monitor thread will block waiting on whoever holds the
lock). If the other thread now requests a monitor operation, it will wait for the monitor thread
do process it, creating a deadlock.
To preserve this invariant I have introduced two new Monitor commands: "begin operation block"
and "end operation block". They begin command blocks the monitor from processing waitpid
events until the corresponding end command, thereby assuring the monitor does not attempt to
acquire the mutex.
Test Plan: Run the test suite locally, verify no tests fail.
Reviewers: vharron, chaoren
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9227
llvm-svn: 236501
Summary:
NativeProcessProtocol uses ReadMemory internally for setting/checking
breakpoints but also for generic memory reads (Handle_m), this change adds a
ReadMemoryWithoutTrap for that purpose. Also fixes a bunch of misuses of addr_t
as size/length.
Test Plan: `disassemble` no longer shows the trap code.
Reviewers: jingham, vharron, clayborg
Reviewed By: clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9330
llvm-svn: 236132
Summary:
Without the synchronisation between the two thread creation events the following case could
happen:
- threads A and B are running. A hits a breakpoint. We note that we want to stop B.
- before we could stop it, B creates a new thread C, we get the stop notification for B, but we
don't record C's existence yet.
- we resume B
- before we get the C notification, B stops again (e.g. hits a breakpoint, gets our SIGSTOP,
etc.)
- we see all known threads have stopped, and we notify LLDB
- C notification comes, we note it's existence and resume it
=> we have an inconsistent state (LLDB thinks we've stopped, but C is running)
I resolve this by doing a blocking wait for for the C notification when we get the creation
notification on the parent (B) thread. This way the two events are synchronised, but we don't
need to introduce the intermediate "launching" state which would complicate handling of thread
states as all code would need to be aware of the third possible state.
Test Plan:
This is an obscure corner case, which I had not observed in practise, so I have no
test for it. I have tested that this commit does not regress in existing tests though.
Reviewers: chaoren, vharron
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9217
llvm-svn: 235969
The previous read callback always read the value of the register what
caused problems when the emulator wrote some value into a register and
then expected to read the same value back. This CL add a register value
cache into the callbacks to return the correct value after a register
write also.
Test Plan: Stepping over BL/BLX instruction works on android-arm if the instruction set isn't change (other, unrelated patch will come for the case when we move to an other instruction set)
Reviewers: omjavaid, sas, clayborg
Reviewed By: clayborg
Subscribers: labath, tberghammer, rengolin, aemerson, lldb-commits
Differential Revision: http://reviews.llvm.org/D9187
From: Tamas Berghammer <tberghammer@google.com>
llvm-svn: 235852
Summary:
LLGS leaks pipes (when launched by lldb), sockets (when launched by platform),
and/or log file to the inferior. This should prevent all possible leaks.
Reviewers: vharron, clayborg
Reviewed By: clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9211
llvm-svn: 235615
The following situation occured if we were stopping a process (due to breakpoint, watchpoint, ...
hit) while a new thread was being created.
- process has two threads: A and B.
- thread A hits a breakpoint: we send a STOP signal to thread B and register a callback with
ThreadStateCoordinator to send a stop notification after the thread stops.
- thread B stops, but not due to the SIGSTOP, but on a thread creation event (of a new thread C).
We are unaware of our desire to stop, so we queue ThreadStopped and RequestResume operations
with TSC, so the thread can continue running.
- TSC receives the ThreadStopped event, sees that all threads are stopped and fires the delayed
stop notification.
- immediately after that TSC gets the RequestResume operation, so it resumes the thread.
At this point the state is inconsistent because LLDB thinks the process is stopped and will start
issuing commands to it, but one of the threads is in fact running. Things eventually break.
I address this problem by omitting the two TSC events altogether and Resuming the thread B
directly. This way the short stop is invisible to the TSC and the delayed notification will not
fire. We will fire the notification when we actually process the SIGSTOP on thread B.
When we get the initial SIGSTOP for thread C, we also resume the thread and send a
ThreadWasCreated message (is_stopped = false) to the TSC. This way, the TSC can stop the thread
on its own and handle the stop event later. This way the state of the new thread is correctly
handled as well (thanks Chaoren for the idea).
This patch also removes the synchronisation between the thread creation notifications on threads
B and C. The need for this synchronisation is unclear (the comments seem to hint that the new
thread is "fully created" only after we process both events, but I have noticed no regressions in
treating it as "created" even after just processing the initial C event), but it is a source for
many kinds of obscure races, since it introduces a new thread state "Launching" and the rest of
the code does not handle this state at all (what happens if we get a resume request from LLDB
while this thread is launching? what happens if we get a stop request? etc.).
This fixes the "spurious $O packet" problem in TestPrintStackTraces.py. However, the test remains
disabled on i386 due to the VDSO issue.
Test Plan:
TestPrintStackTraces works on x86_64. No regressions in the rest of the test suite.
Reviewers: vharron, chaoren
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9145
llvm-svn: 235579
Patch by Jaydeep Patil
Added MIPS32 and MIPS64 core revisions. This would be followed by register context and emulate-instruction for MIPS32.
DYLDRendezvous.cpp:
On Linux link map struct does not contain extra load offset field.
Reviewers: clayborg
Subscribers: bhushan, mohit.bhakkad, sagar, lldb-commits.
Differential Revision: http://reviews.llvm.org/D9190
llvm-svn: 235574
On linux-arm we use software single stepping where setting the new
breakpoint is only possible while the process is in stopped state.
This CL moves the setup code for single stepping form the SigneStep
operation into the Resum method to avoid an error when the process
already started when we want to step one of the thread.
Differential revision: http://reviews.llvm.org/D9108
llvm-svn: 235494
Summary:
This commit moves the functionality of the operation thread into the new monitor thread. This is
required to avoid a kernel race between the two threads and I believe it actually makes the code
cleaner.
Test Plan: Ran the test suite a couple of times, no regressions.
Reviewers: ovyalov, tberghammer, vharron
Subscribers: tberghammer, lldb-commits
Differential Revision: http://reviews.llvm.org/D9080
llvm-svn: 235304
The arm instruction emulation handles only some of the opcode (including
all of them modifying the PC). For the rest of the instructions we can
advance the PC by the size of the instruction as they don't modify the
PC on any other way.
Differential revision: http://reviews.llvm.org/D9076
llvm-svn: 235292
Summary:
This is the first phase of the merging of Monitor and Operation threads in NativeProcessLinux
(which is necessary since the two threads race inside Linux kernel). Here, I reimplement the
Monitor thread do use non-blocking waitpid calls, which enables later addition of code from the
operation thread.
Test Plan: Ran the test suite a couple of times, no regressions detected.
Reviewers: vharron, ovyalov, tberghammer
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D9048
llvm-svn: 235193
Linux arm don't support hardware stepping (neither mismatch
breakpoints). This patch implement signle stepping with doing a software
emulation of the next instruction and then setting a temporary
breakpoint at the address where the thread will stop next.
Differential revision: http://reviews.llvm.org/D8976
llvm-svn: 234987
The automatic conversion from long int to lldb::addr_t caused sign
extension but for a register read it is an unwanted behaviour. Fix with
forcing different conversion path.
llvm-svn: 233176
Previously the remote module sepcification was fetched only from the
remote platform. With this CL if we have a remote process then we ask it
if it have any information from a given module. It is required because
on android the dynamic linker only reports the name of the SO file and
the platform can't always find it without a full path (the process can
do it based on /proc/<pid>/maps).
Differential revision: http://reviews.llvm.org/D8547
llvm-svn: 233061
This CL change the logic used to terminate the monitor thread of
NativeProcessLinux to use a signal instead of pthread_cancel as
pthread_cancel is not supported on android.
Differential revision: http://reviews.llvm.org/D8205
llvm-svn: 232155
This was previously initialized by ProcessGDBRemote::Initialize but lldb-server does not contain ProcessGDBRemote anymore so this needs to be initialized directly.
Differential Revision: http://reviews.llvm.org/D8186
llvm-svn: 231966
Previously it was initialized by ProcessLinux but lldb-server don't
contain ProcessLinux anymore so it have to be initialized by
NativeProcessLinux also.
Differential revision: http://reviews.llvm.org/D8080
llvm-svn: 231482
The deadlock occurred when the Attach or the Launch operation failed for
any reason.
Differential revision: http://reviews.llvm.org/D8030
llvm-svn: 231231
Previously the operation thread is stopped with a cancel event but
pthread_cancel is not supported on android. This CL creates a custom
operation which asks the operation thread to exit without any pthread
call.
Differential revision: http://reviews.llvm.org/D7937
llvm-svn: 230945
Summary:
syscalls involving pid/tid on 32 bit binaries are failing with
"Invalid argument" because the uint64_t arguments are too wide.
Reviewers: clayborg, ovyalov, sivachandra
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D7963
llvm-svn: 230817
Add O_TRUNC when opening file for redirecting stdout and stderr of the
process. It is neccessary because if the file exists then on some
platform the original content is kept while it isn't overwritten by the
new data causing pollution of the saved stdout and stderr.
llvm-svn: 230492
* Fix cmake script for android x86
* Reorder includes to avoid collision between system macros and local
variables in clang framework
Differential Revision: http://reviews.llvm.org/D7435
llvm-svn: 228388
