//===-- ThreadPlanStepThrough.cpp -------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Target/ThreadPlanStepThrough.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Stream.h"
#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/ObjCLanguageRuntime.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Breakpoint/Breakpoint.h"
using namespace lldb;
using namespace lldb_private;
//----------------------------------------------------------------------
// ThreadPlanStepThrough: If the current instruction is a trampoline, step through it
// If it is the beginning of the prologue of a function, step through that as well.
// FIXME: At present only handles DYLD trampolines.
//----------------------------------------------------------------------
ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, StackID &m_stack_id, bool stop_others) :
ThreadPlan (ThreadPlan::eKindStepThrough, "Step through trampolines and prologues", thread, eVoteNoOpinion, eVoteNoOpinion),
m_start_address (0),
m_backstop_bkpt_id (LLDB_INVALID_BREAK_ID),
m_backstop_addr(LLDB_INVALID_ADDRESS),
m_return_stack_id (m_stack_id),
m_stop_others (stop_others)
{
LookForPlanToStepThroughFromCurrentPC();
// If we don't get a valid step through plan, don't bother to set up a backstop.
if (m_sub_plan_sp)
{
m_start_address = GetThread().GetRegisterContext()->GetPC(0);
// We are going to return back to the concrete frame 1, we might pass by some inlined code that we're in
// the middle of by doing this, but it's easier than trying to figure out where the inlined code might return to.
StackFrameSP return_frame_sp = m_thread.GetFrameWithStackID (m_stack_id);
if (return_frame_sp)
{
m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(m_thread.CalculateTarget().get());
Breakpoint *return_bp = m_thread.GetProcess()->GetTarget().CreateBreakpoint (m_backstop_addr, true, false).get();
if (return_bp != nullptr)
{
return_bp->SetThreadID(m_thread.GetID());
m_backstop_bkpt_id = return_bp->GetID();
return_bp->SetBreakpointKind("step-through-backstop");
}
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
{
log->Printf ("Setting backstop breakpoint %d at address: 0x%" PRIx64, m_backstop_bkpt_id, m_backstop_addr);
}
}
}
}
ThreadPlanStepThrough::~ThreadPlanStepThrough ()
{
ClearBackstopBreakpoint ();
}
void
ThreadPlanStepThrough::DidPush ()
{
if (m_sub_plan_sp)
PushPlan(m_sub_plan_sp);
}
void
ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC()
{
DynamicLoader *loader = m_thread.GetProcess()->GetDynamicLoader();
if (loader)
m_sub_plan_sp = loader->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
// If that didn't come up with anything, try the ObjC runtime plugin:
if (!m_sub_plan_sp.get())
{
ObjCLanguageRuntime *objc_runtime = m_thread.GetProcess()->GetObjCLanguageRuntime();
if (objc_runtime)
m_sub_plan_sp = objc_runtime->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
}
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
{
lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0);
if (m_sub_plan_sp)
{
StreamString s;
m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);
log->Printf ("Found step through plan from 0x%" PRIx64 ": %s", current_address, s.GetData());
}
else
{
log->Printf ("Couldn't find step through plan from address 0x%" PRIx64 ".", current_address);
}
}
}
void
ThreadPlanStepThrough::GetDescription (Stream *s, lldb::DescriptionLevel level)
{
if (level == lldb::eDescriptionLevelBrief)
s->Printf ("Step through");
else
{
s->PutCString ("Stepping through trampoline code from: ");
s->Address(m_start_address, sizeof (addr_t));
if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
{
s->Printf(" with backstop breakpoint ID: %d at address: ", m_backstop_bkpt_id);
s->Address (m_backstop_addr, sizeof (addr_t));
}
else
s->PutCString (" unable to set a backstop breakpoint.");
}
}
bool
ThreadPlanStepThrough::ValidatePlan (Stream *error)
{
return m_sub_plan_sp.get() != nullptr;
}
bool
ThreadPlanStepThrough::DoPlanExplainsStop (Event *event_ptr)
{
// If we have a sub-plan, it will have been asked first if we explain the stop, and
// we won't get asked. The only time we would be the one directly asked this question
// is if we hit our backstop breakpoint.
return HitOurBackstopBreakpoint();
}
bool
ThreadPlanStepThrough::ShouldStop (Event *event_ptr)
{
// If we've already marked ourselves done, then we're done...
if (IsPlanComplete())
return true;
// First, did we hit the backstop breakpoint?
if (HitOurBackstopBreakpoint())
{
SetPlanComplete(true);
return true;
}
// If we don't have a sub-plan, then we're also done (can't see how we would ever get here
// without a plan, but just in case.
if (!m_sub_plan_sp)
{
SetPlanComplete();
return true;
}
// If the current sub plan is not done, we don't want to stop. Actually, we probably won't
// ever get here in this state, since we generally won't get asked any questions if out
// current sub-plan is not done...
if (!m_sub_plan_sp->IsPlanComplete())
return false;
// If our current sub plan failed, then let's just run to our backstop. If we can't do that then just stop.
if (!m_sub_plan_sp->PlanSucceeded())
{
if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
{
m_sub_plan_sp.reset();
return false;
}
else
{
SetPlanComplete(false);
return true;
}
}
// Next see if there is a specific step through plan at our current pc (these might
// chain, for instance stepping through a dylib trampoline to the objc dispatch function...)
LookForPlanToStepThroughFromCurrentPC();
if (m_sub_plan_sp)
{
PushPlan (m_sub_plan_sp);
return false;
}
else
{
SetPlanComplete();
return true;
}
}
bool
ThreadPlanStepThrough::StopOthers ()
{
return m_stop_others;
}
StateType
ThreadPlanStepThrough::GetPlanRunState ()
{
return eStateRunning;
}
bool
ThreadPlanStepThrough::DoWillResume (StateType resume_state, bool current_plan)
{
return true;
}
bool
ThreadPlanStepThrough::WillStop ()
{
return true;
}
void
ThreadPlanStepThrough::ClearBackstopBreakpoint ()
{
if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
{
m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
}
}
bool
ThreadPlanStepThrough::MischiefManaged ()
{
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (!IsPlanComplete())
{
return false;
}
else
{
if (log)
log->Printf("Completed step through step plan.");
ClearBackstopBreakpoint ();
ThreadPlan::MischiefManaged ();
return true;
}
}
bool
ThreadPlanStepThrough::HitOurBackstopBreakpoint()
{
StopInfoSP stop_info_sp(m_thread.GetStopInfo());
if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint)
{
break_id_t stop_value = (break_id_t) stop_info_sp->GetValue();
BreakpointSiteSP cur_site_sp = m_thread.GetProcess()->GetBreakpointSiteList().FindByID(stop_value);
if (cur_site_sp && cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id))
{
StackID cur_frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
if (cur_frame_zero_id == m_return_stack_id)
{
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->PutCString ("ThreadPlanStepThrough hit backstop breakpoint.");
return true;
}
}
}
return false;
}
