text: //===-- ThreadPlanStepOut.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/ThreadPlanStepOut.h"
  #include "lldb/Breakpoint/Breakpoint.h"
  #include "lldb/Core/Log.h"
  #include "lldb/Core/Value.h"
  #include "lldb/Core/ValueObjectConstResult.h"
  #include "lldb/Symbol/Block.h"
  #include "lldb/Symbol/Function.h"
  #include "lldb/Symbol/Symbol.h"
  #include "lldb/Symbol/Type.h"
  #include "lldb/Target/ABI.h"
  #include "lldb/Target/Process.h"
  #include "lldb/Target/RegisterContext.h"
  #include "lldb/Target/StopInfo.h"
  #include "lldb/Target/Target.h"
  #include "lldb/Target/ThreadPlanStepOverRange.h"
  #include "lldb/Target/ThreadPlanStepThrough.h"
  
  using namespace lldb;
  using namespace lldb_private;
  
  uint32_t ThreadPlanStepOut::s_default_flag_values = 0;
  
  //----------------------------------------------------------------------
  // ThreadPlanStepOut: Step out of the current frame
  //----------------------------------------------------------------------
  ThreadPlanStepOut::ThreadPlanStepOut
  (
      Thread &thread,
      SymbolContext *context,
      bool first_insn,
      bool stop_others,
      Vote stop_vote,
      Vote run_vote,
      uint32_t frame_idx,
      LazyBool step_out_avoids_code_without_debug_info,
      bool continue_to_next_branch
  ) :
      ThreadPlan (ThreadPlan::eKindStepOut, "Step out", thread, stop_vote, run_vote),
      ThreadPlanShouldStopHere (this),
      m_step_from_insn (LLDB_INVALID_ADDRESS),
      m_return_bp_id (LLDB_INVALID_BREAK_ID),
      m_return_addr (LLDB_INVALID_ADDRESS),
      m_stop_others (stop_others),
      m_immediate_step_from_function(nullptr)
  {
      SetFlagsToDefault();
      SetupAvoidNoDebug(step_out_avoids_code_without_debug_info);
      
      m_step_from_insn = m_thread.GetRegisterContext()->GetPC(0);
  
      StackFrameSP return_frame_sp (m_thread.GetStackFrameAtIndex(frame_idx + 1));
      StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (frame_idx));
      
      if (!return_frame_sp || !immediate_return_from_sp)
          return; // we can't do anything here.  ValidatePlan() will return false.
      
      m_step_out_to_id = return_frame_sp->GetStackID();
      m_immediate_step_from_id = immediate_return_from_sp->GetStackID();
      
      StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
  
      // If the frame directly below the one we are returning to is inlined, we have to be
      // a little more careful.  It is non-trivial to determine the real "return code address" for
      // an inlined frame, so we have to work our way to that frame and then step out.
      if (immediate_return_from_sp && immediate_return_from_sp->IsInlined())
      {
          if (frame_idx > 0)
          {
              // First queue a plan that gets us to this inlined frame, and when we get there we'll queue a second
              // plan that walks us out of this frame.
              m_step_out_to_inline_plan_sp.reset(new ThreadPlanStepOut(m_thread,
                                                                       nullptr,
                                                                       false,
                                                                       stop_others,
                                                                       eVoteNoOpinion,
                                                                       eVoteNoOpinion,
                                                                       frame_idx - 1,
                                                                       eLazyBoolNo,
                                                                       continue_to_next_branch));
              static_cast<ThreadPlanStepOut *>(m_step_out_to_inline_plan_sp.get())->SetShouldStopHereCallbacks(nullptr, nullptr);
              m_step_out_to_inline_plan_sp->SetPrivate(true);
          }
          else
          {
              // If we're already at the inlined frame we're stepping through, then just do that now.
              QueueInlinedStepPlan(false);
          }
      }
      else if (return_frame_sp)
      {
          // Find the return address and set a breakpoint there:
          // FIXME - can we do this more securely if we know first_insn?
  
          Address return_address (return_frame_sp->GetFrameCodeAddress());
          if (continue_to_next_branch)
          {
              SymbolContext return_address_sc;
              AddressRange range;
              Address return_address_decr_pc = return_address;
              if (return_address_decr_pc.GetOffset() > 0)
                  return_address_decr_pc.Slide (-1);
  
              return_address_decr_pc.CalculateSymbolContext (&return_address_sc, lldb::eSymbolContextLineEntry);
              if (return_address_sc.line_entry.IsValid())
              {
                  range = return_address_sc.line_entry.GetSameLineContiguousAddressRange();
                  if (range.GetByteSize() > 0)
                  {
                      return_address = m_thread.GetProcess()->AdvanceAddressToNextBranchInstruction (return_address, 
                                                                                                     range);
                  }
              }
          }
          m_return_addr = return_address.GetLoadAddress(&m_thread.GetProcess()->GetTarget());
          
          if (m_return_addr == LLDB_INVALID_ADDRESS)
              return;
          
          Breakpoint *return_bp = m_thread.CalculateTarget()->CreateBreakpoint (m_return_addr, true, false).get();
          if (return_bp != nullptr)
          {
              return_bp->SetThreadID(m_thread.GetID());
              m_return_bp_id = return_bp->GetID();
              return_bp->SetBreakpointKind ("step-out");
          }
          
          if (immediate_return_from_sp)
          {
              const SymbolContext &sc = immediate_return_from_sp->GetSymbolContext(eSymbolContextFunction);
              if (sc.function)
              {
                  m_immediate_step_from_function = sc.function; 
              }
          }
      }
  }
  
  void
  ThreadPlanStepOut::SetupAvoidNoDebug(LazyBool step_out_avoids_code_without_debug_info)
  {
      bool avoid_nodebug = true;
      switch (step_out_avoids_code_without_debug_info)
      {
          case eLazyBoolYes:
              avoid_nodebug = true;
              break;
          case eLazyBoolNo:
              avoid_nodebug = false;
              break;
          case eLazyBoolCalculate:
              avoid_nodebug = m_thread.GetStepOutAvoidsNoDebug();
              break;
      }
      if (avoid_nodebug)
          GetFlags().Set (ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
      else
          GetFlags().Clear (ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
  }
  
  void
  ThreadPlanStepOut::DidPush()
  {
      if (m_step_out_to_inline_plan_sp)
          m_thread.QueueThreadPlan(m_step_out_to_inline_plan_sp, false);
      else if (m_step_through_inline_plan_sp)
          m_thread.QueueThreadPlan(m_step_through_inline_plan_sp, false);
  }
  
  ThreadPlanStepOut::~ThreadPlanStepOut ()
  {
      if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
          m_thread.CalculateTarget()->RemoveBreakpointByID(m_return_bp_id);
  }
  
  void
  ThreadPlanStepOut::GetDescription (Stream *s, lldb::DescriptionLevel level)
  {
      if (level == lldb::eDescriptionLevelBrief)
          s->Printf ("step out");
      else
      {
          if (m_step_out_to_inline_plan_sp)
              s->Printf ("Stepping out to inlined frame so we can walk through it.");
          else if (m_step_through_inline_plan_sp)
              s->Printf ("Stepping out by stepping through inlined function.");
          else
          {
              s->Printf ("Stepping out from ");
              Address tmp_address;
              if (tmp_address.SetLoadAddress (m_step_from_insn, &GetTarget()))
              {
                  tmp_address.Dump(s, &GetThread(), Address::DumpStyleResolvedDescription, Address::DumpStyleLoadAddress);
              }
              else
              {
                  s->Printf ("address 0x%" PRIx64 "", (uint64_t)m_step_from_insn);
              }
  
              // FIXME: find some useful way to present the m_return_id, since there may be multiple copies of the
              // same function on the stack.
  
              s->Printf (" returning to frame at ");
              if (tmp_address.SetLoadAddress (m_return_addr, &GetTarget()))
              {
                  tmp_address.Dump(s, &GetThread(), Address::DumpStyleResolvedDescription, Address::DumpStyleLoadAddress);
              }
              else
              {
                  s->Printf ("address 0x%" PRIx64 "", (uint64_t)m_return_addr);
              }
  
              if (level == eDescriptionLevelVerbose)
                  s->Printf(" using breakpoint site %d", m_return_bp_id);
          }
      }
  }
  
  bool
  ThreadPlanStepOut::ValidatePlan (Stream *error)
  {
      if (m_step_out_to_inline_plan_sp)
          return m_step_out_to_inline_plan_sp->ValidatePlan (error);
      else if (m_step_through_inline_plan_sp)
          return m_step_through_inline_plan_sp->ValidatePlan (error);
      else if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
      {
          if (error)
              error->PutCString("Could not create return address breakpoint.");
          return false;
      }
      else
          return true;
  }
  
  bool
  ThreadPlanStepOut::DoPlanExplainsStop (Event *event_ptr)
  {
      // If the step out plan is done, then we just need to step through the inlined frame.
      if (m_step_out_to_inline_plan_sp)
      {
          return m_step_out_to_inline_plan_sp->MischiefManaged();
      }
      else if (m_step_through_inline_plan_sp)
      {
          if (m_step_through_inline_plan_sp->MischiefManaged())
          {
              CalculateReturnValue();
              SetPlanComplete();
              return true;
          }
          else
              return false;
      }
      else if (m_step_out_further_plan_sp)
      {
          return m_step_out_further_plan_sp->MischiefManaged();
      }
          
      // We don't explain signals or breakpoints (breakpoints that handle stepping in or
      // out will be handled by a child plan.
      
      StopInfoSP stop_info_sp = GetPrivateStopInfo ();
      if (stop_info_sp)
      {
          StopReason reason = stop_info_sp->GetStopReason();
          if (reason == eStopReasonBreakpoint)
          {
              // If this is OUR breakpoint, we're fine, otherwise we don't know why this happened...
              BreakpointSiteSP site_sp (m_thread.GetProcess()->GetBreakpointSiteList().FindByID (stop_info_sp->GetValue()));
              if (site_sp && site_sp->IsBreakpointAtThisSite (m_return_bp_id))
              {
                  bool done;
                  
                  StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
                  
                  if (m_step_out_to_id == frame_zero_id)
                      done = true;
                  else if (m_step_out_to_id < frame_zero_id)
                  {
                      // Either we stepped past the breakpoint, or the stack ID calculation
                      // was incorrect and we should probably stop.
                      done = true;
                  }
                  else
                  {
                      done = (m_immediate_step_from_id < frame_zero_id);
                  }
                      
                  if (done)
                  {
                      if (InvokeShouldStopHereCallback (eFrameCompareOlder))
                      {
                          CalculateReturnValue();
                          SetPlanComplete();
                      }
                  }
  
                  // If there was only one owner, then we're done.  But if we also hit some
                  // user breakpoint on our way out, we should mark ourselves as done, but
                  // also not claim to explain the stop, since it is more important to report
                  // the user breakpoint than the step out completion.
  
                  if (site_sp->GetNumberOfOwners() == 1)
                      return true;
              }
              return false;
          }
          else if (IsUsuallyUnexplainedStopReason(reason))
              return false;
          else
              return true;
      }
      return true;
  }
  
  bool
  ThreadPlanStepOut::ShouldStop (Event *event_ptr)
  {
      if (IsPlanComplete())
          return true;
      
      bool done = false;
      if (m_step_out_to_inline_plan_sp)
      {
          if (m_step_out_to_inline_plan_sp->MischiefManaged())
          {
              // Now step through the inlined stack we are in:
              if (QueueInlinedStepPlan(true))
              {
                  // If we can't queue a plan to do this, then just call ourselves done.
                  m_step_out_to_inline_plan_sp.reset();
                  SetPlanComplete (false);
                  return true;
              }
              else
                  done = true;
          }
          else
              return m_step_out_to_inline_plan_sp->ShouldStop(event_ptr);
      }
      else if (m_step_through_inline_plan_sp)
      {
          if (m_step_through_inline_plan_sp->MischiefManaged())
              done = true;
          else
              return m_step_through_inline_plan_sp->ShouldStop(event_ptr);
      }
      else if (m_step_out_further_plan_sp)
      {
          if (m_step_out_further_plan_sp->MischiefManaged())
              m_step_out_further_plan_sp.reset();
          else
              return m_step_out_further_plan_sp->ShouldStop(event_ptr);
      }
  
      if (!done)
      {
          StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
          done = !(frame_zero_id < m_step_out_to_id);
      }
  
      // The normal step out computations think we are done, so all we need to do is consult the ShouldStopHere,
      // and we are done.
      
      if (done)
      {
          if (InvokeShouldStopHereCallback(eFrameCompareOlder))
          {
              CalculateReturnValue();
              SetPlanComplete();
          }
          else
          {
              m_step_out_further_plan_sp = QueueStepOutFromHerePlan(m_flags, eFrameCompareOlder);
              done = false;
          }
      }
  
      return done;
  }
  
  bool
  ThreadPlanStepOut::StopOthers ()
  {
      return m_stop_others;
  }
  
  StateType
  ThreadPlanStepOut::GetPlanRunState ()
  {
      return eStateRunning;
  }
  
  bool
  ThreadPlanStepOut::DoWillResume (StateType resume_state, bool current_plan)
  {
      if (m_step_out_to_inline_plan_sp || m_step_through_inline_plan_sp)
          return true;
          
      if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
          return false;
  
      if (current_plan)
      {
          Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
          if (return_bp != nullptr)
              return_bp->SetEnabled (true);
      }
      return true;
  }
  
  bool
  ThreadPlanStepOut::WillStop ()
  {
      if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
      {
          Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
          if (return_bp != nullptr)
              return_bp->SetEnabled (false);
      }
      
      return true;
  }
  
  bool
  ThreadPlanStepOut::MischiefManaged ()
  {
      if (IsPlanComplete())
      {
          // Did I reach my breakpoint?  If so I'm done.
          //
          // I also check the stack depth, since if we've blown past the breakpoint for some
          // reason and we're now stopping for some other reason altogether, then we're done
          // with this step out operation.
  
          Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
          if (log)
              log->Printf("Completed step out plan.");
          if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
          {
              m_thread.CalculateTarget()->RemoveBreakpointByID (m_return_bp_id);
              m_return_bp_id = LLDB_INVALID_BREAK_ID;
          }
          
          ThreadPlan::MischiefManaged ();
          return true;
      }
      else
      {
          return false;
      }
  }
  
  bool
  ThreadPlanStepOut::QueueInlinedStepPlan (bool queue_now)
  {
      // Now figure out the range of this inlined block, and set up a "step through range"
      // plan for that.  If we've been provided with a context, then use the block in that
      // context.  
      StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (0));
      if (!immediate_return_from_sp)
          return false;
          
      Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
      if (log)
      {   
          StreamString s;
          immediate_return_from_sp->Dump(&s, true, false);
          log->Printf("Queuing inlined frame to step past: %s.", s.GetData());
      }
          
      Block *from_block = immediate_return_from_sp->GetFrameBlock();
      if (from_block)
      {
          Block *inlined_block = from_block->GetContainingInlinedBlock();
          if (inlined_block)
          {
              size_t num_ranges = inlined_block->GetNumRanges();
              AddressRange inline_range;
              if (inlined_block->GetRangeAtIndex(0, inline_range))
              {
                  SymbolContext inlined_sc;
                  inlined_block->CalculateSymbolContext(&inlined_sc);
                  inlined_sc.target_sp = GetTarget().shared_from_this();
                  RunMode run_mode = m_stop_others ? lldb::eOnlyThisThread : lldb::eAllThreads;
                  const LazyBool avoid_no_debug = eLazyBoolNo;
  
                  m_step_through_inline_plan_sp.reset (new ThreadPlanStepOverRange(m_thread, 
                                                                                   inline_range, 
                                                                                   inlined_sc, 
                                                                                   run_mode,
                                                                                   avoid_no_debug));
                  ThreadPlanStepOverRange *step_through_inline_plan_ptr
                          = static_cast<ThreadPlanStepOverRange *>(m_step_through_inline_plan_sp.get());
                  m_step_through_inline_plan_sp->SetPrivate(true);
                          
                  step_through_inline_plan_ptr->SetOkayToDiscard(true);                                                                                    
                  StreamString errors;
                  if (!step_through_inline_plan_ptr->ValidatePlan(&errors))
                  {
                      //FIXME: Log this failure.
                      delete step_through_inline_plan_ptr;
                      return false;
                  }
                  
                  for (size_t i = 1; i < num_ranges; i++)
                  {
                      if (inlined_block->GetRangeAtIndex (i, inline_range))
                          step_through_inline_plan_ptr->AddRange (inline_range);
                  }
  
                  if (queue_now)
                      m_thread.QueueThreadPlan (m_step_through_inline_plan_sp, false);
                  return true;
              }
          }
      }
          
      return false;
  }
  
  void
  ThreadPlanStepOut::CalculateReturnValue ()
  {
      if (m_return_valobj_sp)
          return;
          
      if (m_immediate_step_from_function != nullptr)
      {
          CompilerType return_compiler_type = m_immediate_step_from_function->GetCompilerType().GetFunctionReturnType();
          if (return_compiler_type)
          {
              lldb::ABISP abi_sp = m_thread.GetProcess()->GetABI();
              if (abi_sp)
                  m_return_valobj_sp = abi_sp->GetReturnValueObject(m_thread, return_compiler_type);
          }
      }
  }
  
  bool
  ThreadPlanStepOut::IsPlanStale()
  {
      // If we are still lower on the stack than the frame we are returning to, then
      // there's something for us to do.  Otherwise, we're stale.
      
      StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
      return !(frame_zero_id < m_step_out_to_id);
  }
  