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llvm-project/lldb/source/Target/ThreadList.cpp

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//===-- ThreadList.cpp ------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <stdlib.h>
#include <algorithm>
#include "lldb/Core/Log.h"
#include "lldb/Core/State.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/ThreadList.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/Process.h"
using namespace lldb;
using namespace lldb_private;
ThreadList::ThreadList (Process *process) :
ThreadCollection(),
m_process (process),
m_stop_id (0),
m_selected_tid (LLDB_INVALID_THREAD_ID)
{
}
ThreadList::ThreadList (const ThreadList &rhs) :
ThreadCollection(),
m_process (rhs.m_process),
m_stop_id (rhs.m_stop_id),
m_selected_tid ()
{
// Use the assignment operator since it uses the mutex
*this = rhs;
}
const ThreadList&
ThreadList::operator = (const ThreadList& rhs)
{
if (this != &rhs)
{
// Lock both mutexes to make sure neither side changes anyone on us
// while the assignement occurs
Mutex::Locker locker(GetMutex());
m_process = rhs.m_process;
m_stop_id = rhs.m_stop_id;
m_threads = rhs.m_threads;
m_selected_tid = rhs.m_selected_tid;
}
return *this;
}
ThreadList::~ThreadList()
{
// Clear the thread list. Clear will take the mutex lock
// which will ensure that if anyone is using the list
// they won't get it removed while using it.
Clear();
}
uint32_t
ThreadList::GetStopID () const
{
return m_stop_id;
}
void
ThreadList::SetStopID (uint32_t stop_id)
{
m_stop_id = stop_id;
}
uint32_t
ThreadList::GetSize (bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
return m_threads.size();
}
ThreadSP
ThreadList::GetThreadAtIndex (uint32_t idx, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
if (idx < m_threads.size())
thread_sp = m_threads[idx];
return thread_sp;
}
ThreadSP
ThreadList::FindThreadByID (lldb::tid_t tid, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
uint32_t idx = 0;
const uint32_t num_threads = m_threads.size();
for (idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetID() == tid)
{
thread_sp = m_threads[idx];
break;
}
}
return thread_sp;
}
ThreadSP
ThreadList::FindThreadByProtocolID (lldb::tid_t tid, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
uint32_t idx = 0;
const uint32_t num_threads = m_threads.size();
for (idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetProtocolID() == tid)
{
thread_sp = m_threads[idx];
break;
}
}
return thread_sp;
}
ThreadSP
ThreadList::RemoveThreadByID (lldb::tid_t tid, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
uint32_t idx = 0;
const uint32_t num_threads = m_threads.size();
for (idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetID() == tid)
{
thread_sp = m_threads[idx];
m_threads.erase(m_threads.begin()+idx);
break;
}
}
return thread_sp;
}
ThreadSP
ThreadList::RemoveThreadByProtocolID (lldb::tid_t tid, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
uint32_t idx = 0;
const uint32_t num_threads = m_threads.size();
for (idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetProtocolID() == tid)
{
thread_sp = m_threads[idx];
m_threads.erase(m_threads.begin()+idx);
break;
}
}
return thread_sp;
}
ThreadSP
ThreadList::GetThreadSPForThreadPtr (Thread *thread_ptr)
{
ThreadSP thread_sp;
if (thread_ptr)
{
Mutex::Locker locker(GetMutex());
uint32_t idx = 0;
const uint32_t num_threads = m_threads.size();
for (idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx].get() == thread_ptr)
{
thread_sp = m_threads[idx];
break;
}
}
}
return thread_sp;
}
ThreadSP
ThreadList::FindThreadByIndexID (uint32_t index_id, bool can_update)
{
Mutex::Locker locker(GetMutex());
if (can_update)
m_process->UpdateThreadListIfNeeded();
ThreadSP thread_sp;
const uint32_t num_threads = m_threads.size();
for (uint32_t idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetIndexID() == index_id)
{
thread_sp = m_threads[idx];
break;
}
}
return thread_sp;
}
bool
ThreadList::ShouldStop (Event *event_ptr)
{
// Running events should never stop, obviously...
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
// The ShouldStop method of the threads can do a whole lot of work,
// figuring out whether the thread plan conditions are met. So we don't want
// to keep the ThreadList locked the whole time we are doing this.
// FIXME: It is possible that running code could cause new threads
// to be created. If that happens we will miss asking them whether
// then should stop. This is not a big deal, since we haven't had
// a chance to hang any interesting operations on those threads yet.
collection threads_copy;
{
// Scope for locker
Mutex::Locker locker(GetMutex());
m_process->UpdateThreadListIfNeeded();
threads_copy = m_threads;
}
collection::iterator pos, end = threads_copy.end();
if (log)
{
log->PutCString("");
log->Printf ("ThreadList::%s: %" PRIu64 " threads", __FUNCTION__, (uint64_t)m_threads.size());
}
bool did_anybody_stop_for_a_reason = false;
// If the event is an Interrupt event, then we're going to stop no matter what. Otherwise, presume we won't stop.
bool should_stop = false;
if (Process::ProcessEventData::GetInterruptedFromEvent(event_ptr))
{
if (log)
log->Printf("ThreadList::%s handling interrupt event, should stop set to true", __FUNCTION__);
should_stop = true;
}
// Now we run through all the threads and get their stop info's. We want to make sure to do this first before
// we start running the ShouldStop, because one thread's ShouldStop could destroy information (like deleting a
// thread specific breakpoint another thread had stopped at) which could lead us to compute the StopInfo incorrectly.
// We don't need to use it here, we just want to make sure it gets computed.
for (pos = threads_copy.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
thread_sp->GetStopInfo();
}
for (pos = threads_copy.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
// We should never get a stop for which no thread had a stop reason, but sometimes we do see this -
// for instance when we first connect to a remote stub. In that case we should stop, since we can't figure out
// the right thing to do and stopping gives the user control over what to do in this instance.
//
// Note, this causes a problem when you have a thread specific breakpoint, and a bunch of threads hit the breakpoint,
// but not the thread which we are waiting for. All the threads that are not "supposed" to hit the breakpoint
// are marked as having no stop reason, which is right, they should not show a stop reason. But that triggers this
// code and causes us to stop seemingly for no reason.
//
// Since the only way we ever saw this error was on first attach, I'm only going to trigger set did_anybody_stop_for_a_reason
// to true unless this is the first stop.
//
// If this becomes a problem, we'll have to have another StopReason like "StopInfoHidden" which will look invalid
// everywhere but at this check.
if (thread_sp->GetProcess()->GetStopID() > 1)
did_anybody_stop_for_a_reason = true;
else
did_anybody_stop_for_a_reason |= thread_sp->ThreadStoppedForAReason();
const bool thread_should_stop = thread_sp->ShouldStop(event_ptr);
if (thread_should_stop)
should_stop |= true;
}
if (!should_stop && !did_anybody_stop_for_a_reason)
{
should_stop = true;
if (log)
log->Printf ("ThreadList::%s we stopped but no threads had a stop reason, overriding should_stop and stopping.", __FUNCTION__);
}
if (log)
log->Printf ("ThreadList::%s overall should_stop = %i", __FUNCTION__, should_stop);
if (should_stop)
{
for (pos = threads_copy.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
thread_sp->WillStop ();
}
}
return should_stop;
}
Vote
ThreadList::ShouldReportStop (Event *event_ptr)
{
Mutex::Locker locker(GetMutex());
Vote result = eVoteNoOpinion;
m_process->UpdateThreadListIfNeeded();
collection::iterator pos, end = m_threads.end();
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->Printf ("ThreadList::%s %" PRIu64 " threads", __FUNCTION__, (uint64_t)m_threads.size());
// Run through the threads and ask whether we should report this event.
// For stopping, a YES vote wins over everything. A NO vote wins over NO opinion.
for (pos = m_threads.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
const Vote vote = thread_sp->ShouldReportStop (event_ptr);
switch (vote)
{
case eVoteNoOpinion:
continue;
case eVoteYes:
result = eVoteYes;
break;
case eVoteNo:
if (result == eVoteNoOpinion)
{
result = eVoteNo;
}
else
{
if (log)
log->Printf ("ThreadList::%s thread 0x%4.4" PRIx64 ": voted %s, but lost out because result was %s",
__FUNCTION__,
thread_sp->GetID (),
GetVoteAsCString (vote),
GetVoteAsCString (result));
}
break;
}
}
if (log)
log->Printf ("ThreadList::%s returning %s", __FUNCTION__, GetVoteAsCString (result));
return result;
}
void
ThreadList::SetShouldReportStop (Vote vote)
{
Mutex::Locker locker(GetMutex());
m_process->UpdateThreadListIfNeeded();
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
thread_sp->SetShouldReportStop (vote);
}
}
Vote
ThreadList::ShouldReportRun (Event *event_ptr)
{
Mutex::Locker locker(GetMutex());
Vote result = eVoteNoOpinion;
m_process->UpdateThreadListIfNeeded();
collection::iterator pos, end = m_threads.end();
// Run through the threads and ask whether we should report this event.
// The rule is NO vote wins over everything, a YES vote wins over no opinion.
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
for (pos = m_threads.begin(); pos != end; ++pos)
{
if ((*pos)->GetResumeState () != eStateSuspended)
{
switch ((*pos)->ShouldReportRun (event_ptr))
{
case eVoteNoOpinion:
continue;
case eVoteYes:
if (result == eVoteNoOpinion)
result = eVoteYes;
break;
case eVoteNo:
if (log)
log->Printf ("ThreadList::ShouldReportRun() thread %d (0x%4.4" PRIx64 ") says don't report.",
(*pos)->GetIndexID(),
(*pos)->GetID());
result = eVoteNo;
break;
}
}
}
return result;
}
void
ThreadList::Clear()
{
Mutex::Locker locker(GetMutex());
m_stop_id = 0;
m_threads.clear();
m_selected_tid = LLDB_INVALID_THREAD_ID;
}
void
ThreadList::Destroy()
{
Mutex::Locker locker(GetMutex());
const uint32_t num_threads = m_threads.size();
for (uint32_t idx = 0; idx < num_threads; ++idx)
{
m_threads[idx]->DestroyThread();
}
}
void
ThreadList::RefreshStateAfterStop ()
{
Mutex::Locker locker(GetMutex());
m_process->UpdateThreadListIfNeeded();
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log && log->GetVerbose())
log->Printf ("Turning off notification of new threads while single stepping a thread.");
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
(*pos)->RefreshStateAfterStop ();
}
void
ThreadList::DiscardThreadPlans ()
{
// You don't need to update the thread list here, because only threads
// that you currently know about have any thread plans.
Mutex::Locker locker(GetMutex());
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
(*pos)->DiscardThreadPlans (true);
}
bool
ThreadList::WillResume ()
{
// Run through the threads and perform their momentary actions.
// But we only do this for threads that are running, user suspended
// threads stay where they are.
Mutex::Locker locker(GetMutex());
m_process->UpdateThreadListIfNeeded();
collection::iterator pos, end = m_threads.end();
// See if any thread wants to run stopping others. If it does, then we won't
// setup the other threads for resume, since they aren't going to get a chance
// to run. This is necessary because the SetupForResume might add "StopOthers"
// plans which would then get to be part of the who-gets-to-run negotiation, but
// they're coming in after the fact, and the threads that are already set up should
// take priority.
bool wants_solo_run = false;
for (pos = m_threads.begin(); pos != end; ++pos)
{
if ((*pos)->GetResumeState() != eStateSuspended &&
(*pos)->GetCurrentPlan()->StopOthers())
{
if ((*pos)->IsOperatingSystemPluginThread() && !(*pos)->GetBackingThread())
continue;
wants_solo_run = true;
break;
}
}
if (wants_solo_run)
{
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log && log->GetVerbose())
log->Printf ("Turning on notification of new threads while single stepping a thread.");
m_process->StartNoticingNewThreads();
}
else
{
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log && log->GetVerbose())
log->Printf ("Turning off notification of new threads while single stepping a thread.");
m_process->StopNoticingNewThreads();
}
// Give all the threads that are likely to run a last chance to set up their state before we
// negotiate who is actually going to get a chance to run...
// Don't set to resume suspended threads, and if any thread wanted to stop others, only
// call setup on the threads that request StopOthers...
for (pos = m_threads.begin(); pos != end; ++pos)
{
if ((*pos)->GetResumeState() != eStateSuspended
&& (!wants_solo_run || (*pos)->GetCurrentPlan()->StopOthers()))
{
if ((*pos)->IsOperatingSystemPluginThread() && !(*pos)->GetBackingThread())
continue;
(*pos)->SetupForResume ();
}
}
// Now go through the threads and see if any thread wants to run just itself.
// if so then pick one and run it.
ThreadList run_me_only_list (m_process);
run_me_only_list.SetStopID(m_process->GetStopID());
bool run_only_current_thread = false;
for (pos = m_threads.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
if (thread_sp->GetResumeState() != eStateSuspended &&
thread_sp->GetCurrentPlan()->StopOthers())
{
if ((*pos)->IsOperatingSystemPluginThread() && !(*pos)->GetBackingThread())
continue;
// You can't say "stop others" and also want yourself to be suspended.
assert (thread_sp->GetCurrentPlan()->RunState() != eStateSuspended);
if (thread_sp == GetSelectedThread())
{
run_only_current_thread = true;
run_me_only_list.Clear();
run_me_only_list.AddThread (thread_sp);
break;
}
run_me_only_list.AddThread (thread_sp);
}
}
bool need_to_resume = true;
if (run_me_only_list.GetSize (false) == 0)
{
// Everybody runs as they wish:
for (pos = m_threads.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
StateType run_state;
if (thread_sp->GetResumeState() != eStateSuspended)
run_state = thread_sp->GetCurrentPlan()->RunState();
else
run_state = eStateSuspended;
if (!thread_sp->ShouldResume(run_state))
need_to_resume = false;
}
}
else
{
ThreadSP thread_to_run;
if (run_only_current_thread)
{
thread_to_run = GetSelectedThread();
}
else if (run_me_only_list.GetSize (false) == 1)
{
thread_to_run = run_me_only_list.GetThreadAtIndex (0);
}
else
{
int random_thread = (int)
((run_me_only_list.GetSize (false) * (double) rand ()) / (RAND_MAX + 1.0));
thread_to_run = run_me_only_list.GetThreadAtIndex (random_thread);
}
for (pos = m_threads.begin(); pos != end; ++pos)
{
ThreadSP thread_sp(*pos);
if (thread_sp == thread_to_run)
{
if (!thread_sp->ShouldResume(thread_sp->GetCurrentPlan()->RunState()))
need_to_resume = false;
}
else
thread_sp->ShouldResume (eStateSuspended);
}
}
return need_to_resume;
}
void
ThreadList::DidResume ()
{
Mutex::Locker locker(GetMutex());
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
{
// Don't clear out threads that aren't going to get a chance to run, rather
// leave their state for the next time around.
ThreadSP thread_sp(*pos);
if (thread_sp->GetResumeState() != eStateSuspended)
thread_sp->DidResume ();
}
}
void
ThreadList::DidStop ()
{
Mutex::Locker locker(GetMutex());
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
{
// Notify threads that the process just stopped.
// Note, this currently assumes that all threads in the list
// stop when the process stops. In the future we will want to support
// a debugging model where some threads continue to run while others
// are stopped. We either need to handle that somehow here or
// create a special thread list containing only threads which will
// stop in the code that calls this method (currently
// Process::SetPrivateState).
ThreadSP thread_sp(*pos);
if (StateIsRunningState(thread_sp->GetState()))
thread_sp->DidStop ();
}
}
ThreadSP
ThreadList::GetSelectedThread ()
{
Mutex::Locker locker(GetMutex());
ThreadSP thread_sp = FindThreadByID(m_selected_tid);
if (!thread_sp.get())
{
if (m_threads.size() == 0)
return thread_sp;
m_selected_tid = m_threads[0]->GetID();
thread_sp = m_threads[0];
}
return thread_sp;
}
bool
ThreadList::SetSelectedThreadByID (lldb::tid_t tid, bool notify)
{
Mutex::Locker locker(GetMutex());
ThreadSP selected_thread_sp(FindThreadByID(tid));
if (selected_thread_sp)
{
m_selected_tid = tid;
selected_thread_sp->SetDefaultFileAndLineToSelectedFrame();
}
else
m_selected_tid = LLDB_INVALID_THREAD_ID;
if (notify)
NotifySelectedThreadChanged(m_selected_tid);
return m_selected_tid != LLDB_INVALID_THREAD_ID;
}
bool
ThreadList::SetSelectedThreadByIndexID (uint32_t index_id, bool notify)
{
Mutex::Locker locker(GetMutex());
ThreadSP selected_thread_sp (FindThreadByIndexID(index_id));
if (selected_thread_sp.get())
{
m_selected_tid = selected_thread_sp->GetID();
selected_thread_sp->SetDefaultFileAndLineToSelectedFrame();
}
else
m_selected_tid = LLDB_INVALID_THREAD_ID;
if (notify)
NotifySelectedThreadChanged(m_selected_tid);
return m_selected_tid != LLDB_INVALID_THREAD_ID;
}
void
ThreadList::NotifySelectedThreadChanged (lldb::tid_t tid)
{
ThreadSP selected_thread_sp (FindThreadByID(tid));
if (selected_thread_sp->EventTypeHasListeners(Thread::eBroadcastBitThreadSelected))
selected_thread_sp->BroadcastEvent(Thread::eBroadcastBitThreadSelected,
new Thread::ThreadEventData(selected_thread_sp));
}
void
ThreadList::Update (ThreadList &rhs)
{
if (this != &rhs)
{
// Lock both mutexes to make sure neither side changes anyone on us
// while the assignement occurs
Mutex::Locker locker(GetMutex());
m_process = rhs.m_process;
m_stop_id = rhs.m_stop_id;
m_threads.swap(rhs.m_threads);
m_selected_tid = rhs.m_selected_tid;
// Now we look for threads that we are done with and
// make sure to clear them up as much as possible so
// anyone with a shared pointer will still have a reference,
// but the thread won't be of much use. Using std::weak_ptr
// for all backward references (such as a thread to a process)
// will eventually solve this issue for us, but for now, we
// need to work around the issue
collection::iterator rhs_pos, rhs_end = rhs.m_threads.end();
for (rhs_pos = rhs.m_threads.begin(); rhs_pos != rhs_end; ++rhs_pos)
{
const lldb::tid_t tid = (*rhs_pos)->GetID();
bool thread_is_alive = false;
const uint32_t num_threads = m_threads.size();
for (uint32_t idx = 0; idx < num_threads; ++idx)
{
if (m_threads[idx]->GetID() == tid)
{
thread_is_alive = true;
break;
}
}
if (!thread_is_alive)
(*rhs_pos)->DestroyThread();
}
}
}
void
ThreadList::Flush ()
{
Mutex::Locker locker(GetMutex());
collection::iterator pos, end = m_threads.end();
for (pos = m_threads.begin(); pos != end; ++pos)
(*pos)->Flush ();
}
Mutex &
ThreadList::GetMutex ()
{
return m_process->m_thread_mutex;
}
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