UnwindPlanSP
FuncUnwinders::GetUnwindPlanArchitectureDefaultAtFunctionEntry (Thread& thread)
{
// Lock the mutex to ensure we can always give out the most appropriate
// information. We want to make sure if someone requests an unwind
// plan, that they get one and don't run into a race condition where one
// thread has started to create the unwind plan and has put it into
// the auto_ptr member variable, and have another thread enter this function
// and return the partially filled pointer contained in the auto_ptr.
// We also want to make sure that we lock out other unwind plans from
// being accessed until this one is done creating itself in case someone
// had some code like:
// UnwindPlan *best_unwind_plan = ...GetUnwindPlanAtCallSite (...)
// if (best_unwind_plan == NULL)
// best_unwind_plan = GetUnwindPlanAtNonCallSite (...)
Mutex::Locker locker (m_mutex);
if (m_tried_unwind_arch_default_at_func_entry == false && m_unwind_plan_arch_default_at_func_entry_sp.get() == NULL)
{
m_tried_unwind_arch_default_at_func_entry = true;
Address current_pc;
ProcessSP process_sp (thread.CalculateProcess());
if (process_sp)
{
ABI *abi = process_sp->GetABI().get();
if (abi)
{
m_unwind_plan_arch_default_at_func_entry_sp.reset (new UnwindPlan (lldb::eRegisterKindGeneric));
if (m_unwind_plan_arch_default_at_func_entry_sp)
abi->CreateFunctionEntryUnwindPlan(*m_unwind_plan_arch_default_at_func_entry_sp);
}
}
}
return m_unwind_plan_arch_default_sp;
}
UnwindPlanSP
FuncUnwinders::GetUnwindPlanArchitectureDefaultAtFunctionEntry (Thread& thread)
{
if (m_unwind_plan_arch_default_at_func_entry_sp.get() || m_tried_unwind_arch_default_at_func_entry)
return m_unwind_plan_arch_default_at_func_entry_sp;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
m_tried_unwind_arch_default_at_func_entry = true;
Address current_pc;
ProcessSP process_sp (thread.CalculateProcess());
if (process_sp)
{
ABI *abi = process_sp->GetABI().get();
if (abi)
{
m_unwind_plan_arch_default_at_func_entry_sp.reset (new UnwindPlan (lldb::eRegisterKindGeneric));
if (!abi->CreateFunctionEntryUnwindPlan(*m_unwind_plan_arch_default_at_func_entry_sp))
{
m_unwind_plan_arch_default_at_func_entry_sp.reset();
}
}
}
return m_unwind_plan_arch_default_at_func_entry_sp;
}