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