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