contrib/llvm/tools/lldb/source/Target/ThreadPlanStepInstruction.cpp

   1 //===-- ThreadPlanStepInstruction.cpp ---------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Target/ThreadPlanStepInstruction.h"
  10 #include "lldb/Target/Process.h"
  11 #include "lldb/Target/RegisterContext.h"
  12 #include "lldb/Target/RegisterContext.h"
  13 #include "lldb/Target/StopInfo.h"
  14 #include "lldb/Target/Target.h"
  15 #include "lldb/Utility/Log.h"
  16 #include "lldb/Utility/Stream.h"
  17
  18 using namespace lldb;
  19 using namespace lldb_private;
  20
  21 // ThreadPlanStepInstruction: Step over the current instruction
  22
  23 ThreadPlanStepInstruction::ThreadPlanStepInstruction(Thread &thread,
  24                                                      bool step_over,
  25                                                      bool stop_other_threads,
  26                                                      Vote stop_vote,
  27                                                      Vote run_vote)
  28     : ThreadPlan(ThreadPlan::eKindStepInstruction,
  29                  "Step over single instruction", thread, stop_vote, run_vote),
  30       m_instruction_addr(0), m_stop_other_threads(stop_other_threads),
  31       m_step_over(step_over) {
  32   m_takes_iteration_count = true;
  33   SetUpState();
  34 }
  35
  36 ThreadPlanStepInstruction::~ThreadPlanStepInstruction() = default;
  37
  38 void ThreadPlanStepInstruction::SetUpState() {
  39   m_instruction_addr = m_thread.GetRegisterContext()->GetPC(0);
  40   StackFrameSP start_frame_sp(m_thread.GetStackFrameAtIndex(0));
  41   m_stack_id = start_frame_sp->GetStackID();
  42
  43   m_start_has_symbol =
  44       start_frame_sp->GetSymbolContext(eSymbolContextSymbol).symbol != nullptr;
  45
  46   StackFrameSP parent_frame_sp = m_thread.GetStackFrameAtIndex(1);
  47   if (parent_frame_sp)
  48     m_parent_frame_id = parent_frame_sp->GetStackID();
  49 }
  50
  51 void ThreadPlanStepInstruction::GetDescription(Stream *s,
  52                                                lldb::DescriptionLevel level) {
  53   auto PrintFailureIfAny = [&]() {
  54     if (m_status.Success())
  55       return;
  56     s->Printf(" failed (%s)", m_status.AsCString());
  57   };
  58
  59   if (level == lldb::eDescriptionLevelBrief) {
  60     if (m_step_over)
  61       s->Printf("instruction step over");
  62     else
  63       s->Printf("instruction step into");
  64
  65     PrintFailureIfAny();
  66   } else {
  67     s->Printf("Stepping one instruction past ");
  68     s->Address(m_instruction_addr, sizeof(addr_t));
  69     if (!m_start_has_symbol)
  70       s->Printf(" which has no symbol");
  71
  72     if (m_step_over)
  73       s->Printf(" stepping over calls");
  74     else
  75       s->Printf(" stepping into calls");
  76
  77     PrintFailureIfAny();
  78   }
  79 }
  80
  81 bool ThreadPlanStepInstruction::ValidatePlan(Stream *error) {
  82   // Since we read the instruction we're stepping over from the thread, this
  83   // plan will always work.
  84   return true;
  85 }
  86
  87 bool ThreadPlanStepInstruction::DoPlanExplainsStop(Event *event_ptr) {
  88   StopInfoSP stop_info_sp = GetPrivateStopInfo();
  89   if (stop_info_sp) {
  90     StopReason reason = stop_info_sp->GetStopReason();
  91     return (reason == eStopReasonTrace || reason == eStopReasonNone);
  92   }
  93   return false;
  94 }
  95
  96 bool ThreadPlanStepInstruction::IsPlanStale() {
  97   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
  98   StackID cur_frame_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
  99   if (cur_frame_id == m_stack_id) {
 100     // Set plan Complete when we reach next instruction
 101     uint64_t pc = m_thread.GetRegisterContext()->GetPC(0);
 102     uint32_t max_opcode_size = m_thread.CalculateTarget()
 103         ->GetArchitecture().GetMaximumOpcodeByteSize();
 104     bool next_instruction_reached = (pc > m_instruction_addr) &&
 105         (pc <= m_instruction_addr + max_opcode_size);
 106     if (next_instruction_reached) {
 107       SetPlanComplete();
 108     }
 109     return (m_thread.GetRegisterContext()->GetPC(0) != m_instruction_addr);
 110   } else if (cur_frame_id < m_stack_id) {
 111     // If the current frame is younger than the start frame and we are stepping
 112     // over, then we need to continue, but if we are doing just one step, we're
 113     // done.
 114     return !m_step_over;
 115   } else {
 116     if (log) {
 117       log->Printf("ThreadPlanStepInstruction::IsPlanStale - Current frame is "
 118                   "older than start frame, plan is stale.");
 119     }
 120     return true;
 121   }
 122 }
 123
 124 bool ThreadPlanStepInstruction::ShouldStop(Event *event_ptr) {
 125   if (m_step_over) {
 126     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 127
 128     StackFrameSP cur_frame_sp = m_thread.GetStackFrameAtIndex(0);
 129     if (!cur_frame_sp) {
 130       if (log)
 131         log->Printf(
 132             "ThreadPlanStepInstruction couldn't get the 0th frame, stopping.");
 133       SetPlanComplete();
 134       return true;
 135     }
 136
 137     StackID cur_frame_zero_id = cur_frame_sp->GetStackID();
 138
 139     if (cur_frame_zero_id == m_stack_id || m_stack_id < cur_frame_zero_id) {
 140       if (m_thread.GetRegisterContext()->GetPC(0) != m_instruction_addr) {
 141         if (--m_iteration_count <= 0) {
 142           SetPlanComplete();
 143           return true;
 144         } else {
 145           // We are still stepping, reset the start pc, and in case we've
 146           // stepped out, reset the current stack id.
 147           SetUpState();
 148           return false;
 149         }
 150       } else
 151         return false;
 152     } else {
 153       // We've stepped in, step back out again:
 154       StackFrame *return_frame = m_thread.GetStackFrameAtIndex(1).get();
 155       if (return_frame) {
 156         if (return_frame->GetStackID() != m_parent_frame_id ||
 157             m_start_has_symbol) {
 158           // next-instruction shouldn't step out of inlined functions.  But we
 159           // may have stepped into a real function that starts with an inlined
 160           // function, and we do want to step out of that...
 161
 162           if (cur_frame_sp->IsInlined()) {
 163             StackFrameSP parent_frame_sp =
 164                 m_thread.GetFrameWithStackID(m_stack_id);
 165
 166             if (parent_frame_sp &&
 167                 parent_frame_sp->GetConcreteFrameIndex() ==
 168                     cur_frame_sp->GetConcreteFrameIndex()) {
 169               SetPlanComplete();
 170               if (log) {
 171                 log->Printf("Frame we stepped into is inlined into the frame "
 172                             "we were stepping from, stopping.");
 173               }
 174               return true;
 175             }
 176           }
 177
 178           if (log) {
 179             StreamString s;
 180             s.PutCString("Stepped in to: ");
 181             addr_t stop_addr =
 182                 m_thread.GetStackFrameAtIndex(0)->GetRegisterContext()->GetPC();
 183             s.Address(stop_addr, m_thread.CalculateTarget()
 184                                      ->GetArchitecture()
 185                                      .GetAddressByteSize());
 186             s.PutCString(" stepping out to: ");
 187             addr_t return_addr = return_frame->GetRegisterContext()->GetPC();
 188             s.Address(return_addr, m_thread.CalculateTarget()
 189                                        ->GetArchitecture()
 190                                        .GetAddressByteSize());
 191             log->Printf("%s.", s.GetData());
 192           }
 193
 194           // StepInstruction should probably have the tri-state RunMode, but
 195           // for now it is safer to run others.
 196           const bool stop_others = false;
 197           m_thread.QueueThreadPlanForStepOutNoShouldStop(
 198               false, nullptr, true, stop_others, eVoteNo, eVoteNoOpinion, 0,
 199               m_status);
 200           return false;
 201         } else {
 202           if (log) {
 203             log->PutCString(
 204                 "The stack id we are stepping in changed, but our parent frame "
 205                 "did not when stepping from code with no symbols.  "
 206                 "We are probably just confused about where we are, stopping.");
 207           }
 208           SetPlanComplete();
 209           return true;
 210         }
 211       } else {
 212         if (log)
 213           log->Printf("Could not find previous frame, stopping.");
 214         SetPlanComplete();
 215         return true;
 216       }
 217     }
 218   } else {
 219     lldb::addr_t pc_addr = m_thread.GetRegisterContext()->GetPC(0);
 220     if (pc_addr != m_instruction_addr) {
 221       if (--m_iteration_count <= 0) {
 222         SetPlanComplete();
 223         return true;
 224       } else {
 225         // We are still stepping, reset the start pc, and in case we've stepped
 226         // in or out, reset the current stack id.
 227         SetUpState();
 228         return false;
 229       }
 230     } else
 231       return false;
 232   }
 233 }
 234
 235 bool ThreadPlanStepInstruction::StopOthers() { return m_stop_other_threads; }
 236
 237 StateType ThreadPlanStepInstruction::GetPlanRunState() {
 238   return eStateStepping;
 239 }
 240
 241 bool ThreadPlanStepInstruction::WillStop() { return true; }
 242
 243 bool ThreadPlanStepInstruction::MischiefManaged() {
 244   if (IsPlanComplete()) {
 245     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 246     if (log)
 247       log->Printf("Completed single instruction step plan.");
 248     ThreadPlan::MischiefManaged();
 249     return true;
 250   } else {
 251     return false;
 252   }
 253 }