1 //===-- ThreadPlanStepOverRange.cpp ---------------------------------------===//
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/ThreadPlanStepOverRange.h"
10 #include "lldb/Symbol/Block.h"
11 #include "lldb/Symbol/CompileUnit.h"
12 #include "lldb/Symbol/Function.h"
13 #include "lldb/Symbol/LineTable.h"
14 #include "lldb/Target/Process.h"
15 #include "lldb/Target/RegisterContext.h"
16 #include "lldb/Target/Target.h"
17 #include "lldb/Target/Thread.h"
18 #include "lldb/Target/ThreadPlanStepOut.h"
19 #include "lldb/Target/ThreadPlanStepThrough.h"
20 #include "lldb/Utility/Log.h"
21 #include "lldb/Utility/Stream.h"
22
23 using namespace lldb_private;
24 using namespace lldb;
25
26 uint32_t ThreadPlanStepOverRange::s_default_flag_values = 0;
27
28 // ThreadPlanStepOverRange: Step through a stack range, either stepping over or
29 // into based on the value of \a type.
30
ThreadPlanStepOverRange(Thread & thread,const AddressRange & range,const SymbolContext & addr_context,lldb::RunMode stop_others,LazyBool step_out_avoids_code_without_debug_info)31 ThreadPlanStepOverRange::ThreadPlanStepOverRange(
32 Thread &thread, const AddressRange &range,
33 const SymbolContext &addr_context, lldb::RunMode stop_others,
34 LazyBool step_out_avoids_code_without_debug_info)
35 : ThreadPlanStepRange(ThreadPlan::eKindStepOverRange,
36 "Step range stepping over", thread, range,
37 addr_context, stop_others),
38 ThreadPlanShouldStopHere(this), m_first_resume(true) {
39 SetFlagsToDefault();
40 SetupAvoidNoDebug(step_out_avoids_code_without_debug_info);
41 }
42
43 ThreadPlanStepOverRange::~ThreadPlanStepOverRange() = default;
44
GetDescription(Stream * s,lldb::DescriptionLevel level)45 void ThreadPlanStepOverRange::GetDescription(Stream *s,
46 lldb::DescriptionLevel level) {
47 auto PrintFailureIfAny = [&]() {
48 if (m_status.Success())
49 return;
50 s->Printf(" failed (%s)", m_status.AsCString());
51 };
52
53 if (level == lldb::eDescriptionLevelBrief) {
54 s->Printf("step over");
55 PrintFailureIfAny();
56 return;
57 }
58
59 s->Printf("Stepping over");
60 bool printed_line_info = false;
61 if (m_addr_context.line_entry.IsValid()) {
62 s->Printf(" line ");
63 m_addr_context.line_entry.DumpStopContext(s, false);
64 printed_line_info = true;
65 }
66
67 if (!printed_line_info || level == eDescriptionLevelVerbose) {
68 s->Printf(" using ranges: ");
69 DumpRanges(s);
70 }
71
72 PrintFailureIfAny();
73
74 s->PutChar('.');
75 }
76
SetupAvoidNoDebug(LazyBool step_out_avoids_code_without_debug_info)77 void ThreadPlanStepOverRange::SetupAvoidNoDebug(
78 LazyBool step_out_avoids_code_without_debug_info) {
79 bool avoid_nodebug = true;
80 switch (step_out_avoids_code_without_debug_info) {
81 case eLazyBoolYes:
82 avoid_nodebug = true;
83 break;
84 case eLazyBoolNo:
85 avoid_nodebug = false;
86 break;
87 case eLazyBoolCalculate:
88 avoid_nodebug = GetThread().GetStepOutAvoidsNoDebug();
89 break;
90 }
91 if (avoid_nodebug)
92 GetFlags().Set(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
93 else
94 GetFlags().Clear(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
95 // Step Over plans should always avoid no-debug on step in. Seems like you
96 // shouldn't have to say this, but a tail call looks more like a step in that
97 // a step out, so we want to catch this case.
98 GetFlags().Set(ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
99 }
100
IsEquivalentContext(const SymbolContext & context)101 bool ThreadPlanStepOverRange::IsEquivalentContext(
102 const SymbolContext &context) {
103 // Match as much as is specified in the m_addr_context: This is a fairly
104 // loose sanity check. Note, sometimes the target doesn't get filled in so I
105 // left out the target check. And sometimes the module comes in as the .o
106 // file from the inlined range, so I left that out too...
107 if (m_addr_context.comp_unit) {
108 if (m_addr_context.comp_unit != context.comp_unit)
109 return false;
110 if (m_addr_context.function) {
111 if (m_addr_context.function != context.function)
112 return false;
113 // It is okay to return to a different block of a straight function, we
114 // only have to be more careful if returning from one inlined block to
115 // another.
116 if (m_addr_context.block->GetInlinedFunctionInfo() == nullptr &&
117 context.block->GetInlinedFunctionInfo() == nullptr)
118 return true;
119 return m_addr_context.block == context.block;
120 }
121 }
122 // Fall back to symbol if we have no decision from comp_unit/function/block.
123 return m_addr_context.symbol && m_addr_context.symbol == context.symbol;
124 }
125
ShouldStop(Event * event_ptr)126 bool ThreadPlanStepOverRange::ShouldStop(Event *event_ptr) {
127 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
128 Thread &thread = GetThread();
129
130 if (log) {
131 StreamString s;
132 DumpAddress(s.AsRawOstream(), thread.GetRegisterContext()->GetPC(),
133 GetTarget().GetArchitecture().GetAddressByteSize());
134 LLDB_LOGF(log, "ThreadPlanStepOverRange reached %s.", s.GetData());
135 }
136
137 // If we're out of the range but in the same frame or in our caller's frame
138 // then we should stop. When stepping out we only stop others if we are
139 // forcing running one thread.
140 bool stop_others = (m_stop_others == lldb::eOnlyThisThread);
141 ThreadPlanSP new_plan_sp;
142 FrameComparison frame_order = CompareCurrentFrameToStartFrame();
143
144 if (frame_order == eFrameCompareOlder) {
145 // If we're in an older frame then we should stop.
146 //
147 // A caveat to this is if we think the frame is older but we're actually in
148 // a trampoline.
149 // I'm going to make the assumption that you wouldn't RETURN to a
150 // trampoline. So if we are in a trampoline we think the frame is older
151 // because the trampoline confused the backtracer. As below, we step
152 // through first, and then try to figure out how to get back out again.
153
154 new_plan_sp = thread.QueueThreadPlanForStepThrough(m_stack_id, false,
155 stop_others, m_status);
156
157 if (new_plan_sp && log)
158 LLDB_LOGF(log,
159 "Thought I stepped out, but in fact arrived at a trampoline.");
160 } else if (frame_order == eFrameCompareYounger) {
161 // Make sure we really are in a new frame. Do that by unwinding and seeing
162 // if the start function really is our start function...
163 for (uint32_t i = 1;; ++i) {
164 StackFrameSP older_frame_sp = thread.GetStackFrameAtIndex(i);
165 if (!older_frame_sp) {
166 // We can't unwind the next frame we should just get out of here &
167 // stop...
168 break;
169 }
170
171 const SymbolContext &older_context =
172 older_frame_sp->GetSymbolContext(eSymbolContextEverything);
173 if (IsEquivalentContext(older_context)) {
174 // If we have the next-branch-breakpoint in the range, we can just
175 // rely on that breakpoint to trigger once we return to the range.
176 if (m_next_branch_bp_sp)
177 return false;
178 new_plan_sp = thread.QueueThreadPlanForStepOutNoShouldStop(
179 false, nullptr, true, stop_others, eVoteNo, eVoteNoOpinion, 0,
180 m_status, true);
181 break;
182 } else {
183 new_plan_sp = thread.QueueThreadPlanForStepThrough(
184 m_stack_id, false, stop_others, m_status);
185 // If we found a way through, then we should stop recursing.
186 if (new_plan_sp)
187 break;
188 }
189 }
190 } else {
191 // If we're still in the range, keep going.
192 if (InRange()) {
193 SetNextBranchBreakpoint();
194 return false;
195 }
196
197 if (!InSymbol()) {
198 // This one is a little tricky. Sometimes we may be in a stub or
199 // something similar, in which case we need to get out of there. But if
200 // we are in a stub then it's likely going to be hard to get out from
201 // here. It is probably easiest to step into the stub, and then it will
202 // be straight-forward to step out.
203 new_plan_sp = thread.QueueThreadPlanForStepThrough(m_stack_id, false,
204 stop_others, m_status);
205 } else {
206 // The current clang (at least through 424) doesn't always get the
207 // address range for the DW_TAG_inlined_subroutines right, so that when
208 // you leave the inlined range the line table says you are still in the
209 // source file of the inlining function. This is bad, because now you
210 // are missing the stack frame for the function containing the inlining,
211 // and if you sensibly do "finish" to get out of this function you will
212 // instead exit the containing function. To work around this, we check
213 // whether we are still in the source file we started in, and if not
214 // assume it is an error, and push a plan to get us out of this line and
215 // back to the containing file.
216
217 if (m_addr_context.line_entry.IsValid()) {
218 SymbolContext sc;
219 StackFrameSP frame_sp = thread.GetStackFrameAtIndex(0);
220 sc = frame_sp->GetSymbolContext(eSymbolContextEverything);
221 if (sc.line_entry.IsValid()) {
222 if (sc.line_entry.original_file !=
223 m_addr_context.line_entry.original_file &&
224 sc.comp_unit == m_addr_context.comp_unit &&
225 sc.function == m_addr_context.function) {
226 // Okay, find the next occurrence of this file in the line table:
227 LineTable *line_table = m_addr_context.comp_unit->GetLineTable();
228 if (line_table) {
229 Address cur_address = frame_sp->GetFrameCodeAddress();
230 uint32_t entry_idx;
231 LineEntry line_entry;
232 if (line_table->FindLineEntryByAddress(cur_address, line_entry,
233 &entry_idx)) {
234 LineEntry next_line_entry;
235 bool step_past_remaining_inline = false;
236 if (entry_idx > 0) {
237 // We require the previous line entry and the current line
238 // entry come from the same file. The other requirement is
239 // that the previous line table entry be part of an inlined
240 // block, we don't want to step past cases where people have
241 // inlined some code fragment by using #include <source-
242 // fragment.c> directly.
243 LineEntry prev_line_entry;
244 if (line_table->GetLineEntryAtIndex(entry_idx - 1,
245 prev_line_entry) &&
246 prev_line_entry.original_file ==
247 line_entry.original_file) {
248 SymbolContext prev_sc;
249 Address prev_address =
250 prev_line_entry.range.GetBaseAddress();
251 prev_address.CalculateSymbolContext(&prev_sc);
252 if (prev_sc.block) {
253 Block *inlined_block =
254 prev_sc.block->GetContainingInlinedBlock();
255 if (inlined_block) {
256 AddressRange inline_range;
257 inlined_block->GetRangeContainingAddress(prev_address,
258 inline_range);
259 if (!inline_range.ContainsFileAddress(cur_address)) {
260
261 step_past_remaining_inline = true;
262 }
263 }
264 }
265 }
266 }
267
268 if (step_past_remaining_inline) {
269 uint32_t look_ahead_step = 1;
270 while (line_table->GetLineEntryAtIndex(
271 entry_idx + look_ahead_step, next_line_entry)) {
272 // Make sure we haven't wandered out of the function we
273 // started from...
274 Address next_line_address =
275 next_line_entry.range.GetBaseAddress();
276 Function *next_line_function =
277 next_line_address.CalculateSymbolContextFunction();
278 if (next_line_function != m_addr_context.function)
279 break;
280
281 if (next_line_entry.original_file ==
282 m_addr_context.line_entry.original_file) {
283 const bool abort_other_plans = false;
284 const RunMode stop_other_threads = RunMode::eAllThreads;
285 lldb::addr_t cur_pc = thread.GetStackFrameAtIndex(0)
286 ->GetRegisterContext()
287 ->GetPC();
288 AddressRange step_range(
289 cur_pc,
290 next_line_address.GetLoadAddress(&GetTarget()) -
291 cur_pc);
292
293 new_plan_sp = thread.QueueThreadPlanForStepOverRange(
294 abort_other_plans, step_range, sc, stop_other_threads,
295 m_status);
296 break;
297 }
298 look_ahead_step++;
299 }
300 }
301 }
302 }
303 }
304 }
305 }
306 }
307 }
308
309 // If we get to this point, we're not going to use a previously set "next
310 // branch" breakpoint, so delete it:
311 ClearNextBranchBreakpoint();
312
313 // If we haven't figured out something to do yet, then ask the ShouldStopHere
314 // callback:
315 if (!new_plan_sp) {
316 new_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order, m_status);
317 }
318
319 if (!new_plan_sp)
320 m_no_more_plans = true;
321 else {
322 // Any new plan will be an implementation plan, so mark it private:
323 new_plan_sp->SetPrivate(true);
324 m_no_more_plans = false;
325 }
326
327 if (!new_plan_sp) {
328 // For efficiencies sake, we know we're done here so we don't have to do
329 // this calculation again in MischiefManaged.
330 SetPlanComplete(m_status.Success());
331 return true;
332 } else
333 return false;
334 }
335
DoPlanExplainsStop(Event * event_ptr)336 bool ThreadPlanStepOverRange::DoPlanExplainsStop(Event *event_ptr) {
337 // For crashes, breakpoint hits, signals, etc, let the base plan (or some
338 // plan above us) handle the stop. That way the user can see the stop, step
339 // around, and then when they are done, continue and have their step
340 // complete. The exception is if we've hit our "run to next branch"
341 // breakpoint. Note, unlike the step in range plan, we don't mark ourselves
342 // complete if we hit an unexplained breakpoint/crash.
343
344 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
345 StopInfoSP stop_info_sp = GetPrivateStopInfo();
346 bool return_value;
347
348 if (stop_info_sp) {
349 StopReason reason = stop_info_sp->GetStopReason();
350
351 if (reason == eStopReasonTrace) {
352 return_value = true;
353 } else if (reason == eStopReasonBreakpoint) {
354 return_value = NextRangeBreakpointExplainsStop(stop_info_sp);
355 } else {
356 if (log)
357 log->PutCString("ThreadPlanStepInRange got asked if it explains the "
358 "stop for some reason other than step.");
359 return_value = false;
360 }
361 } else
362 return_value = true;
363
364 return return_value;
365 }
366
DoWillResume(lldb::StateType resume_state,bool current_plan)367 bool ThreadPlanStepOverRange::DoWillResume(lldb::StateType resume_state,
368 bool current_plan) {
369 if (resume_state != eStateSuspended && m_first_resume) {
370 m_first_resume = false;
371 if (resume_state == eStateStepping && current_plan) {
372 Thread &thread = GetThread();
373 // See if we are about to step over an inlined call in the middle of the
374 // inlined stack, if so figure out its extents and reset our range to
375 // step over that.
376 bool in_inlined_stack = thread.DecrementCurrentInlinedDepth();
377 if (in_inlined_stack) {
378 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
379 LLDB_LOGF(log,
380 "ThreadPlanStepInRange::DoWillResume: adjusting range to "
381 "the frame at inlined depth %d.",
382 thread.GetCurrentInlinedDepth());
383 StackFrameSP stack_sp = thread.GetStackFrameAtIndex(0);
384 if (stack_sp) {
385 Block *frame_block = stack_sp->GetFrameBlock();
386 lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
387 AddressRange my_range;
388 if (frame_block->GetRangeContainingLoadAddress(
389 curr_pc, m_process.GetTarget(), my_range)) {
390 m_address_ranges.clear();
391 m_address_ranges.push_back(my_range);
392 if (log) {
393 StreamString s;
394 const InlineFunctionInfo *inline_info =
395 frame_block->GetInlinedFunctionInfo();
396 const char *name;
397 if (inline_info)
398 name = inline_info->GetName().AsCString();
399 else
400 name = "<unknown-notinlined>";
401
402 s.Printf(
403 "Stepping over inlined function \"%s\" in inlined stack: ",
404 name);
405 DumpRanges(&s);
406 log->PutString(s.GetString());
407 }
408 }
409 }
410 }
411 }
412 }
413
414 return true;
415 }
416