source/Target/ThreadPlanStepThrough.cpp

   1 //===-- ThreadPlanStepThrough.cpp -------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 // C Includes
  11 // C++ Includes
  12 // Other libraries and framework includes
  13 // Project includes
  14 #include "lldb/Target/ThreadPlanStepThrough.h"
  15 #include "lldb/Core/Log.h"
  16 #include "lldb/Core/Stream.h"
  17 #include "lldb/Target/DynamicLoader.h"
  18 #include "lldb/Target/ObjCLanguageRuntime.h"
  19 #include "lldb/Target/Process.h"
  20 #include "lldb/Target/RegisterContext.h"
  21 #include "lldb/Target/Target.h"
  22 #include "lldb/Breakpoint/Breakpoint.h"
  23
  24 using namespace lldb;
  25 using namespace lldb_private;
  26
  27 //----------------------------------------------------------------------
  28 // ThreadPlanStepThrough: If the current instruction is a trampoline, step through it
  29 // If it is the beginning of the prologue of a function, step through that as well.
  30 // FIXME: At present only handles DYLD trampolines.
  31 //----------------------------------------------------------------------
  32
  33 ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, StackID &m_stack_id, bool stop_others) :
  34     ThreadPlan (ThreadPlan::eKindStepThrough, "Step through trampolines and prologues", thread, eVoteNoOpinion, eVoteNoOpinion),
  35     m_start_address (0),
  36     m_backstop_bkpt_id (LLDB_INVALID_BREAK_ID),
  37     m_backstop_addr(LLDB_INVALID_ADDRESS),
  38     m_return_stack_id (m_stack_id),
  39     m_stop_others (stop_others)
  40 {
  41     LookForPlanToStepThroughFromCurrentPC();
  42
  43     // If we don't get a valid step through plan, don't bother to set up a backstop.
  44     if (m_sub_plan_sp)
  45     {
  46         m_start_address = GetThread().GetRegisterContext()->GetPC(0);
  47
  48         // We are going to return back to the concrete frame 1, we might pass by some inlined code that we're in
  49         // the middle of by doing this, but it's easier than trying to figure out where the inlined code might return to.
  50
  51         StackFrameSP return_frame_sp = m_thread.GetFrameWithStackID (m_stack_id);
  52
  53         if (return_frame_sp)
  54         {
  55             m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(m_thread.CalculateTarget().get());
  56             Breakpoint *return_bp = m_thread.GetProcess()->GetTarget().CreateBreakpoint (m_backstop_addr, true, false).get();
  57             if (return_bp != nullptr)
  58             {
  59                 return_bp->SetThreadID(m_thread.GetID());
  60                 m_backstop_bkpt_id = return_bp->GetID();
  61                 return_bp->SetBreakpointKind("step-through-backstop");
  62             }
  63             Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
  64             if (log)
  65             {
  66                 log->Printf ("Setting backstop breakpoint %d at address: 0x%" PRIx64, m_backstop_bkpt_id, m_backstop_addr);
  67             }
  68         }
  69     }
  70 }
  71
  72 ThreadPlanStepThrough::~ThreadPlanStepThrough ()
  73 {
  74     ClearBackstopBreakpoint ();
  75 }
  76
  77 void
  78 ThreadPlanStepThrough::DidPush ()
  79 {
  80     if (m_sub_plan_sp)
  81         PushPlan(m_sub_plan_sp);
  82 }
  83
  84 void
  85 ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC()
  86 {
  87     DynamicLoader *loader = m_thread.GetProcess()->GetDynamicLoader();
  88     if (loader)
  89         m_sub_plan_sp = loader->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
  90
  91     // If that didn't come up with anything, try the ObjC runtime plugin:
  92     if (!m_sub_plan_sp.get())
  93     {
  94         ObjCLanguageRuntime *objc_runtime = m_thread.GetProcess()->GetObjCLanguageRuntime();
  95         if (objc_runtime)
  96             m_sub_plan_sp = objc_runtime->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
  97     }
  98
  99     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
 100     if (log)
 101     {
 102         lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0);
 103         if (m_sub_plan_sp)
 104         {
 105             StreamString s;
 106             m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);
 107             log->Printf ("Found step through plan from 0x%" PRIx64 ": %s", current_address, s.GetData());
 108         }
 109         else
 110         {
 111             log->Printf ("Couldn't find step through plan from address 0x%" PRIx64 ".", current_address);
 112         }
 113     }
 114 }
 115
 116 void
 117 ThreadPlanStepThrough::GetDescription (Stream *s, lldb::DescriptionLevel level)
 118 {
 119     if (level == lldb::eDescriptionLevelBrief)
 120         s->Printf ("Step through");
 121     else
 122     {
 123         s->PutCString ("Stepping through trampoline code from: ");
 124         s->Address(m_start_address, sizeof (addr_t));
 125         if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
 126         {
 127             s->Printf (" with backstop breakpoint id: %d at address: ", m_backstop_bkpt_id);
 128             s->Address (m_backstop_addr, sizeof (addr_t));
 129         }
 130         else
 131             s->PutCString (" unable to set a backstop breakpoint.");
 132     }
 133 }
 134
 135 bool
 136 ThreadPlanStepThrough::ValidatePlan (Stream *error)
 137 {
 138     return m_sub_plan_sp.get() != nullptr;
 139 }
 140
 141 bool
 142 ThreadPlanStepThrough::DoPlanExplainsStop (Event *event_ptr)
 143 {
 144     // If we have a sub-plan, it will have been asked first if we explain the stop, and
 145     // we won't get asked.  The only time we would be the one directly asked this question
 146     // is if we hit our backstop breakpoint.
 147
 148     return HitOurBackstopBreakpoint();
 149 }
 150
 151 bool
 152 ThreadPlanStepThrough::ShouldStop (Event *event_ptr)
 153 {
 154     // If we've already marked ourselves done, then we're done...
 155     if (IsPlanComplete())
 156         return true;
 157
 158     // First, did we hit the backstop breakpoint?
 159     if (HitOurBackstopBreakpoint())
 160     {
 161         SetPlanComplete(true);
 162         return true;
 163     }
 164
 165     // If we don't have a sub-plan, then we're also done (can't see how we would ever get here
 166     // without a plan, but just in case.
 167
 168     if (!m_sub_plan_sp)
 169     {
 170         SetPlanComplete();
 171         return true;
 172     }
 173
 174     // If the current sub plan is not done, we don't want to stop.  Actually, we probably won't
 175     // ever get here in this state, since we generally won't get asked any questions if out
 176     // current sub-plan is not done...
 177     if (!m_sub_plan_sp->IsPlanComplete())
 178         return false;
 179
 180     // If our current sub plan failed, then let's just run to our backstop.  If we can't do that then just stop.
 181     if (!m_sub_plan_sp->PlanSucceeded())
 182     {
 183         if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
 184         {
 185             m_sub_plan_sp.reset();
 186             return false;
 187         }
 188         else
 189         {
 190             SetPlanComplete(false);
 191             return true;
 192         }
 193     }
 194
 195     // Next see if there is a specific step through plan at our current pc (these might
 196     // chain, for instance stepping through a dylib trampoline to the objc dispatch function...)
 197     LookForPlanToStepThroughFromCurrentPC();
 198     if (m_sub_plan_sp)
 199     {
 200         PushPlan (m_sub_plan_sp);
 201         return false;
 202     }
 203     else
 204     {
 205         SetPlanComplete();
 206         return true;
 207     }
 208 }
 209
 210 bool
 211 ThreadPlanStepThrough::StopOthers ()
 212 {
 213     return m_stop_others;
 214 }
 215
 216 StateType
 217 ThreadPlanStepThrough::GetPlanRunState ()
 218 {
 219     return eStateRunning;
 220 }
 221
 222 bool
 223 ThreadPlanStepThrough::DoWillResume (StateType resume_state, bool current_plan)
 224 {
 225     return true;
 226 }
 227
 228 bool
 229 ThreadPlanStepThrough::WillStop ()
 230 {
 231     return true;
 232 }
 233
 234 void
 235 ThreadPlanStepThrough::ClearBackstopBreakpoint ()
 236 {
 237     if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
 238     {
 239         m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
 240         m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
 241     }
 242 }
 243
 244 bool
 245 ThreadPlanStepThrough::MischiefManaged ()
 246 {
 247     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
 248
 249     if (!IsPlanComplete())
 250     {
 251         return false;
 252     }
 253     else
 254     {
 255         if (log)
 256             log->Printf("Completed step through step plan.");
 257
 258         ClearBackstopBreakpoint ();
 259         ThreadPlan::MischiefManaged ();
 260         return true;
 261     }
 262 }
 263
 264 bool
 265 ThreadPlanStepThrough::HitOurBackstopBreakpoint()
 266 {
 267     StopInfoSP stop_info_sp(m_thread.GetStopInfo());
 268     if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint)
 269     {
 270         break_id_t stop_value = (break_id_t) stop_info_sp->GetValue();
 271         BreakpointSiteSP cur_site_sp = m_thread.GetProcess()->GetBreakpointSiteList().FindByID(stop_value);
 272         if (cur_site_sp && cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id))
 273         {
 274             StackID cur_frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
 275
 276             if (cur_frame_zero_id == m_return_stack_id)
 277             {
 278                 Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
 279                 if (log)
 280                     log->PutCString ("ThreadPlanStepThrough hit backstop breakpoint.");
 281                 return true;
 282             }
 283         }
 284     }
 285     return false;
 286 }