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
12 // C Includes
13 // C++ Includes
14 // Other libraries and framework includes
15 // Project includes
16 #include "lldb/lldb-private-log.h"
17 #include "lldb/Core/Log.h"
18 #include "lldb/Core/Stream.h"
19 #include "lldb/Target/DynamicLoader.h"
20 #include "lldb/Target/ObjCLanguageRuntime.h"
21 #include "lldb/Target/Process.h"
22 #include "lldb/Target/RegisterContext.h"
23 #include "lldb/Target/Target.h"
24 #include "lldb/Breakpoint/Breakpoint.h"
25
26 using namespace lldb;
27 using namespace lldb_private;
28
29 //----------------------------------------------------------------------
30 // ThreadPlanStepThrough: If the current instruction is a trampoline, step through it
31 // If it is the beginning of the prologue of a function, step through that as well.
32 // FIXME: At present only handles DYLD trampolines.
33 //----------------------------------------------------------------------
34
ThreadPlanStepThrough(Thread & thread,StackID & m_stack_id,bool stop_others)35 ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, StackID &m_stack_id, bool stop_others) :
36 ThreadPlan (ThreadPlan::eKindStepThrough, "Step through trampolines and prologues", thread, eVoteNoOpinion, eVoteNoOpinion),
37 m_start_address (0),
38 m_backstop_bkpt_id (LLDB_INVALID_BREAK_ID),
39 m_backstop_addr(LLDB_INVALID_ADDRESS),
40 m_return_stack_id (m_stack_id),
41 m_stop_others (stop_others)
42 {
43
44 LookForPlanToStepThroughFromCurrentPC();
45
46 // If we don't get a valid step through plan, don't bother to set up a backstop.
47 if (m_sub_plan_sp)
48 {
49 m_start_address = GetThread().GetRegisterContext()->GetPC(0);
50
51 // We are going to return back to the concrete frame 1, we might pass by some inlined code that we're in
52 // the middle of by doing this, but it's easier than trying to figure out where the inlined code might return to.
53
54 StackFrameSP return_frame_sp = m_thread.GetFrameWithStackID (m_stack_id);
55
56 if (return_frame_sp)
57 {
58 m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(m_thread.CalculateTarget().get());
59 Breakpoint *return_bp = m_thread.GetProcess()->GetTarget().CreateBreakpoint (m_backstop_addr, true).get();
60 if (return_bp != NULL)
61 {
62 return_bp->SetThreadID(m_thread.GetID());
63 m_backstop_bkpt_id = return_bp->GetID();
64 return_bp->SetBreakpointKind("step-through-backstop");
65 }
66 Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
67 if (log)
68 {
69 log->Printf ("Setting backstop breakpoint %d at address: 0x%" PRIx64, m_backstop_bkpt_id, m_backstop_addr);
70 }
71 }
72 }
73 }
74
~ThreadPlanStepThrough()75 ThreadPlanStepThrough::~ThreadPlanStepThrough ()
76 {
77 ClearBackstopBreakpoint ();
78 }
79
80 void
DidPush()81 ThreadPlanStepThrough::DidPush ()
82 {
83 if (m_sub_plan_sp)
84 PushPlan(m_sub_plan_sp);
85 }
86
87 void
LookForPlanToStepThroughFromCurrentPC()88 ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC()
89 {
90 m_sub_plan_sp = m_thread.GetProcess()->GetDynamicLoader()->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
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
GetDescription(Stream * s,lldb::DescriptionLevel level)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
ValidatePlan(Stream * error)136 ThreadPlanStepThrough::ValidatePlan (Stream *error)
137 {
138 return m_sub_plan_sp.get() != NULL;
139 }
140
141 bool
DoPlanExplainsStop(Event * event_ptr)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 if (HitOurBackstopBreakpoint())
149 return true;
150 else
151 return false;
152 }
153
154 bool
ShouldStop(Event * event_ptr)155 ThreadPlanStepThrough::ShouldStop (Event *event_ptr)
156 {
157 // If we've already marked ourselves done, then we're done...
158 if (IsPlanComplete())
159 return true;
160
161 // First, did we hit the backstop breakpoint?
162 if (HitOurBackstopBreakpoint())
163 {
164 SetPlanComplete(false);
165 return true;
166 }
167
168 // If we don't have a sub-plan, then we're also done (can't see how we would ever get here
169 // without a plan, but just in case.
170
171 if (!m_sub_plan_sp)
172 {
173 SetPlanComplete();
174 return true;
175 }
176
177 // If the current sub plan is not done, we don't want to stop. Actually, we probably won't
178 // ever get here in this state, since we generally won't get asked any questions if out
179 // current sub-plan is not done...
180 if (!m_sub_plan_sp->IsPlanComplete())
181 return false;
182
183 // If our current sub plan failed, then let's just run to our backstop. If we can't do that then just stop.
184 if (!m_sub_plan_sp->PlanSucceeded())
185 {
186 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
187 {
188 m_sub_plan_sp.reset();
189 return false;
190 }
191 else
192 {
193 SetPlanComplete(false);
194 return true;
195 }
196 }
197
198 // Next see if there is a specific step through plan at our current pc (these might
199 // chain, for instance stepping through a dylib trampoline to the objc dispatch function...)
200 LookForPlanToStepThroughFromCurrentPC();
201 if (m_sub_plan_sp)
202 {
203 PushPlan (m_sub_plan_sp);
204 return false;
205 }
206 else
207 {
208 SetPlanComplete();
209 return true;
210 }
211 }
212
213 bool
StopOthers()214 ThreadPlanStepThrough::StopOthers ()
215 {
216 return m_stop_others;
217 }
218
219 StateType
GetPlanRunState()220 ThreadPlanStepThrough::GetPlanRunState ()
221 {
222 return eStateRunning;
223 }
224
225 bool
DoWillResume(StateType resume_state,bool current_plan)226 ThreadPlanStepThrough::DoWillResume (StateType resume_state, bool current_plan)
227 {
228 return true;
229 }
230
231 bool
WillStop()232 ThreadPlanStepThrough::WillStop ()
233 {
234 return true;
235 }
236
237 void
ClearBackstopBreakpoint()238 ThreadPlanStepThrough::ClearBackstopBreakpoint ()
239 {
240 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
241 {
242 m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
243 m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
244 }
245 }
246
247 bool
MischiefManaged()248 ThreadPlanStepThrough::MischiefManaged ()
249 {
250 Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
251
252 if (!IsPlanComplete())
253 {
254 return false;
255 }
256 else
257 {
258 if (log)
259 log->Printf("Completed step through step plan.");
260
261 ClearBackstopBreakpoint ();
262 ThreadPlan::MischiefManaged ();
263 return true;
264 }
265 }
266
267 bool
HitOurBackstopBreakpoint()268 ThreadPlanStepThrough::HitOurBackstopBreakpoint()
269 {
270 StopInfoSP stop_info_sp(m_thread.GetStopInfo());
271 if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint)
272 {
273 break_id_t stop_value = (break_id_t) stop_info_sp->GetValue();
274 BreakpointSiteSP cur_site_sp = m_thread.GetProcess()->GetBreakpointSiteList().FindByID(stop_value);
275 if (cur_site_sp && cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id))
276 {
277 StackID cur_frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
278
279 if (cur_frame_zero_id == m_return_stack_id)
280 {
281 Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
282 if (log)
283 log->PutCString ("ThreadPlanStepThrough hit backstop breakpoint.");
284 return true;
285 }
286 }
287 }
288 return false;
289 }
290
291