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Guard against the C++ destructor chain by not letting the debugger list clean up after itself in the C++ destructor chain. 

If users call "static void lldb::SBDebugger::Terminate()" we will clean up the debugger list, and users can individually destroy debugger instances with "static void lldb::SBDebugger::Destroy(SBDebugger &)". But if we let the C++ destructor chain tear down this list, other threads that might still be running as the main thread exits can now crash if they access the debugger list. We stop this by leaking the debugger list and its mutex.

<rdar://problem/26372169>

llvm-svn: 270869
This commit is contained in:
Greg Clayton 2016-05-26 16:51:23 +00:00
parent 6782e944d2
commit 6c42e06312
1 changed files with 49 additions and 67 deletions
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116
lldb/source/Core/Debugger.cpp
View File

@ -68,23 +68,9 @@ static size_t g_debugger_event_thread_stack_bytes = 8 * 1024 * 1024;
#pragma mark Static Functions
static std::recursive_mutex &
GetDebuggerListMutex()
{
static std::recursive_mutex g_mutex;
return g_mutex;
}
typedef std::vector<DebuggerSP> DebuggerList;
static DebuggerList &
GetDebuggerList()
{
// hide the static debugger list inside a singleton accessor to avoid
// global init constructors
static DebuggerList g_list;
return g_list;
}
static std::recursive_mutex *g_debugger_list_mutex_ptr = nullptr; // NOTE: intentional leak to avoid issues with C++ destructor chain
static DebuggerList *g_debugger_list_ptr = nullptr; // NOTE: intentional leak to avoid issues with C++ destructor chain
OptionEnumValueElement
g_show_disassembly_enum_values[] =
@ -454,28 +440,32 @@ Debugger::SetTabSize (uint32_t tab_size)
//}
//
static bool lldb_initialized = false;
void
Debugger::Initialize(LoadPluginCallbackType load_plugin_callback)
{
assert(!lldb_initialized && "Debugger::Initialize called more than once!");
lldb_initialized = true;
assert(g_debugger_list_ptr == nullptr && "Debugger::Initialize called more than once!");
g_debugger_list_mutex_ptr = new std::recursive_mutex();
g_debugger_list_ptr = new DebuggerList();
g_load_plugin_callback = load_plugin_callback;
}
void
Debugger::Terminate ()
{
assert(lldb_initialized && "Debugger::Terminate called without a matching Debugger::Initialize!");
assert(g_debugger_list_ptr && "Debugger::Terminate called without a matching Debugger::Initialize!");
// Clear our master list of debugger objects
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
auto& debuggers = GetDebuggerList();
for (const auto& debugger: debuggers)
debugger->Clear();
debuggers.clear();
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
// Clear our master list of debugger objects
{
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
for (const auto& debugger: *g_debugger_list_ptr)
debugger->Clear();
g_debugger_list_ptr->clear();
delete g_debugger_list_ptr;
g_debugger_list_ptr = nullptr;
}
}
}
void
@ -604,10 +594,10 @@ DebuggerSP
Debugger::CreateInstance (lldb::LogOutputCallback log_callback, void *baton)
{
DebuggerSP debugger_sp (new Debugger(log_callback, baton));
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
GetDebuggerList().push_back(debugger_sp);
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
g_debugger_list_ptr->push_back(debugger_sp);
}
debugger_sp->InstanceInitialize ();
return debugger_sp;
@ -621,16 +611,15 @@ Debugger::Destroy (DebuggerSP &debugger_sp)
debugger_sp->Clear();
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList ();
DebuggerList::iterator pos, end = debugger_list.end();
for (pos = debugger_list.begin (); pos != end; ++pos)
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
for (pos = g_debugger_list_ptr->begin (); pos != end; ++pos)
{
if ((*pos).get() == debugger_sp.get())
{
debugger_list.erase (pos);
g_debugger_list_ptr->erase (pos);
return;
}
}
@ -641,13 +630,11 @@ DebuggerSP
Debugger::FindDebuggerWithInstanceName (const ConstString &instance_name)
{
DebuggerSP debugger_sp;
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList();
DebuggerList::iterator pos, end = debugger_list.end();
for (pos = debugger_list.begin(); pos != end; ++pos)
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
for (pos = g_debugger_list_ptr->begin (); pos != end; ++pos)
{
if ((*pos)->m_instance_name == instance_name)
{
@ -663,12 +650,11 @@ TargetSP
Debugger::FindTargetWithProcessID (lldb::pid_t pid)
{
TargetSP target_sp;
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList();
DebuggerList::iterator pos, end = debugger_list.end();
for (pos = debugger_list.begin(); pos != end; ++pos)
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
for (pos = g_debugger_list_ptr->begin (); pos != end; ++pos)
{
target_sp = (*pos)->GetTargetList().FindTargetWithProcessID (pid);
if (target_sp)
@ -682,12 +668,11 @@ TargetSP
Debugger::FindTargetWithProcess (Process *process)
{
TargetSP target_sp;
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList();
DebuggerList::iterator pos, end = debugger_list.end();
for (pos = debugger_list.begin(); pos != end; ++pos)
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
for (pos = g_debugger_list_ptr->begin (); pos != end; ++pos)
{
target_sp = (*pos)->GetTargetList().FindTargetWithProcess (process);
if (target_sp)
@ -1162,10 +1147,10 @@ Debugger::GetAsyncErrorStream ()
size_t
Debugger::GetNumDebuggers()
{
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
return GetDebuggerList().size();
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
return g_debugger_list_ptr->size();
}
return 0;
}
@ -1175,13 +1160,11 @@ Debugger::GetDebuggerAtIndex (size_t index)
{
DebuggerSP debugger_sp;
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList();
if (index < debugger_list.size())
debugger_sp = debugger_list[index];
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
if (index < g_debugger_list_ptr->size())
debugger_sp = g_debugger_list_ptr->at(index);
}
return debugger_sp;
@ -1192,12 +1175,11 @@ Debugger::FindDebuggerWithID (lldb::user_id_t id)
{
DebuggerSP debugger_sp;
if (lldb_initialized)
if (g_debugger_list_ptr && g_debugger_list_mutex_ptr)
{
std::lock_guard<std::recursive_mutex> guard(GetDebuggerListMutex());
DebuggerList &debugger_list = GetDebuggerList();
DebuggerList::iterator pos, end = debugger_list.end();
for (pos = debugger_list.begin(); pos != end; ++pos)
std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
for (pos = g_debugger_list_ptr->begin (); pos != end; ++pos)
{
if ((*pos)->GetID() == id)
{