1 //===-- ThreadPlanStepRange.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/ThreadPlanStepRange.h"
10 #include "lldb/Breakpoint/BreakpointLocation.h"
11 #include "lldb/Breakpoint/BreakpointSite.h"
12 #include "lldb/Core/Disassembler.h"
13 #include "lldb/Symbol/Function.h"
14 #include "lldb/Symbol/Symbol.h"
15 #include "lldb/Target/ExecutionContext.h"
16 #include "lldb/Target/Process.h"
17 #include "lldb/Target/RegisterContext.h"
18 #include "lldb/Target/StopInfo.h"
19 #include "lldb/Target/Target.h"
20 #include "lldb/Target/Thread.h"
21 #include "lldb/Target/ThreadPlanRunToAddress.h"
22 #include "lldb/Utility/LLDBLog.h"
23 #include "lldb/Utility/Log.h"
24 #include "lldb/Utility/Stream.h"
25
26 using namespace lldb;
27 using namespace lldb_private;
28
29 // ThreadPlanStepRange: Step through a stack range, either stepping over or
30 // into based on the value of \a type.
31
ThreadPlanStepRange(ThreadPlanKind kind,const char * name,Thread & thread,const AddressRange & range,const SymbolContext & addr_context,lldb::RunMode stop_others,bool given_ranges_only)32 ThreadPlanStepRange::ThreadPlanStepRange(ThreadPlanKind kind, const char *name,
33 Thread &thread,
34 const AddressRange &range,
35 const SymbolContext &addr_context,
36 lldb::RunMode stop_others,
37 bool given_ranges_only)
38 : ThreadPlan(kind, name, thread, eVoteNoOpinion, eVoteNoOpinion),
39 m_addr_context(addr_context), m_address_ranges(),
40 m_stop_others(stop_others), m_stack_id(), m_parent_stack_id(),
41 m_no_more_plans(false), m_first_run_event(true), m_use_fast_step(false),
42 m_given_ranges_only(given_ranges_only) {
43 m_use_fast_step = GetTarget().GetUseFastStepping();
44 AddRange(range);
45 m_stack_id = thread.GetStackFrameAtIndex(0)->GetStackID();
46 StackFrameSP parent_stack = thread.GetStackFrameAtIndex(1);
47 if (parent_stack)
48 m_parent_stack_id = parent_stack->GetStackID();
49 }
50
~ThreadPlanStepRange()51 ThreadPlanStepRange::~ThreadPlanStepRange() { ClearNextBranchBreakpoint(); }
52
DidPush()53 void ThreadPlanStepRange::DidPush() {
54 // See if we can find a "next range" breakpoint:
55 SetNextBranchBreakpoint();
56 }
57
ValidatePlan(Stream * error)58 bool ThreadPlanStepRange::ValidatePlan(Stream *error) {
59 if (m_could_not_resolve_hw_bp) {
60 if (error)
61 error->PutCString(
62 "Could not create hardware breakpoint for thread plan.");
63 return false;
64 }
65 return true;
66 }
67
ShouldReportStop(Event * event_ptr)68 Vote ThreadPlanStepRange::ShouldReportStop(Event *event_ptr) {
69 Log *log = GetLog(LLDBLog::Step);
70
71 const Vote vote = IsPlanComplete() ? eVoteYes : eVoteNo;
72 LLDB_LOGF(log, "ThreadPlanStepRange::ShouldReportStop() returning vote %i\n",
73 vote);
74 return vote;
75 }
76
AddRange(const AddressRange & new_range)77 void ThreadPlanStepRange::AddRange(const AddressRange &new_range) {
78 // For now I'm just adding the ranges. At some point we may want to condense
79 // the ranges if they overlap, though I don't think it is likely to be very
80 // important.
81 m_address_ranges.push_back(new_range);
82
83 // Fill the slot for this address range with an empty DisassemblerSP in the
84 // instruction ranges. I want the indices to match, but I don't want to do
85 // the work to disassemble this range if I don't step into it.
86 m_instruction_ranges.push_back(DisassemblerSP());
87 }
88
DumpRanges(Stream * s)89 void ThreadPlanStepRange::DumpRanges(Stream *s) {
90 size_t num_ranges = m_address_ranges.size();
91 if (num_ranges == 1) {
92 m_address_ranges[0].Dump(s, &GetTarget(), Address::DumpStyleLoadAddress);
93 } else {
94 for (size_t i = 0; i < num_ranges; i++) {
95 s->Printf(" %" PRIu64 ": ", uint64_t(i));
96 m_address_ranges[i].Dump(s, &GetTarget(), Address::DumpStyleLoadAddress);
97 }
98 }
99 }
100
InRange()101 bool ThreadPlanStepRange::InRange() {
102 Log *log = GetLog(LLDBLog::Step);
103 bool ret_value = false;
104 Thread &thread = GetThread();
105 lldb::addr_t pc_load_addr = thread.GetRegisterContext()->GetPC();
106
107 size_t num_ranges = m_address_ranges.size();
108 for (size_t i = 0; i < num_ranges; i++) {
109 ret_value =
110 m_address_ranges[i].ContainsLoadAddress(pc_load_addr, &GetTarget());
111 if (ret_value)
112 break;
113 }
114
115 if (!ret_value && !m_given_ranges_only) {
116 // See if we've just stepped to another part of the same line number...
117 StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
118
119 SymbolContext new_context(
120 frame->GetSymbolContext(eSymbolContextEverything));
121 if (m_addr_context.line_entry.IsValid() &&
122 new_context.line_entry.IsValid()) {
123 if (m_addr_context.line_entry.original_file_sp->Equal(
124 *new_context.line_entry.original_file_sp,
125 SupportFile::eEqualFileSpecAndChecksumIfSet)) {
126 if (m_addr_context.line_entry.line == new_context.line_entry.line) {
127 m_addr_context = new_context;
128 const bool include_inlined_functions =
129 GetKind() == eKindStepOverRange;
130 AddRange(m_addr_context.line_entry.GetSameLineContiguousAddressRange(
131 include_inlined_functions));
132 ret_value = true;
133 if (log) {
134 StreamString s;
135 m_addr_context.line_entry.Dump(&s, &GetTarget(), true,
136 Address::DumpStyleLoadAddress,
137 Address::DumpStyleLoadAddress, true);
138
139 LLDB_LOGF(
140 log,
141 "Step range plan stepped to another range of same line: %s",
142 s.GetData());
143 }
144 } else if (new_context.line_entry.line == 0) {
145 new_context.line_entry.line = m_addr_context.line_entry.line;
146 m_addr_context = new_context;
147 const bool include_inlined_functions =
148 GetKind() == eKindStepOverRange;
149 AddRange(m_addr_context.line_entry.GetSameLineContiguousAddressRange(
150 include_inlined_functions));
151 ret_value = true;
152 if (log) {
153 StreamString s;
154 m_addr_context.line_entry.Dump(&s, &GetTarget(), true,
155 Address::DumpStyleLoadAddress,
156 Address::DumpStyleLoadAddress, true);
157
158 LLDB_LOGF(log,
159 "Step range plan stepped to a range at linenumber 0 "
160 "stepping through that range: %s",
161 s.GetData());
162 }
163 } else if (new_context.line_entry.range.GetBaseAddress().GetLoadAddress(
164 &GetTarget()) != pc_load_addr) {
165 // Another thing that sometimes happens here is that we step out of
166 // one line into the MIDDLE of another line. So far I mostly see
167 // this due to bugs in the debug information. But we probably don't
168 // want to be in the middle of a line range, so in that case reset
169 // the stepping range to the line we've stepped into the middle of
170 // and continue.
171 m_addr_context = new_context;
172 m_address_ranges.clear();
173 AddRange(m_addr_context.line_entry.range);
174 ret_value = true;
175 if (log) {
176 StreamString s;
177 m_addr_context.line_entry.Dump(&s, &GetTarget(), true,
178 Address::DumpStyleLoadAddress,
179 Address::DumpStyleLoadAddress, true);
180
181 LLDB_LOGF(log,
182 "Step range plan stepped to the middle of new "
183 "line(%d): %s, continuing to clear this line.",
184 new_context.line_entry.line, s.GetData());
185 }
186 }
187 }
188 }
189 }
190
191 if (!ret_value && log)
192 LLDB_LOGF(log, "Step range plan out of range to 0x%" PRIx64, pc_load_addr);
193
194 return ret_value;
195 }
196
InSymbol()197 bool ThreadPlanStepRange::InSymbol() {
198 lldb::addr_t cur_pc = GetThread().GetRegisterContext()->GetPC();
199 if (m_addr_context.function != nullptr) {
200 AddressRange unused_range;
201 return m_addr_context.function->GetRangeContainingLoadAddress(
202 cur_pc, GetTarget(), unused_range);
203 }
204 if (m_addr_context.symbol && m_addr_context.symbol->ValueIsAddress()) {
205 AddressRange range(m_addr_context.symbol->GetAddressRef(),
206 m_addr_context.symbol->GetByteSize());
207 return range.ContainsLoadAddress(cur_pc, &GetTarget());
208 }
209 return false;
210 }
211
212 // FIXME: This should also handle inlining if we aren't going to do inlining in
213 // the
214 // main stack.
215 //
216 // Ideally we should remember the whole stack frame list, and then compare that
217 // to the current list.
218
CompareCurrentFrameToStartFrame()219 lldb::FrameComparison ThreadPlanStepRange::CompareCurrentFrameToStartFrame() {
220 FrameComparison frame_order;
221 Thread &thread = GetThread();
222 StackID cur_frame_id = thread.GetStackFrameAtIndex(0)->GetStackID();
223
224 if (cur_frame_id == m_stack_id) {
225 frame_order = eFrameCompareEqual;
226 } else if (cur_frame_id < m_stack_id) {
227 frame_order = eFrameCompareYounger;
228 } else {
229 StackFrameSP cur_parent_frame = thread.GetStackFrameAtIndex(1);
230 StackID cur_parent_id;
231 if (cur_parent_frame)
232 cur_parent_id = cur_parent_frame->GetStackID();
233 if (m_parent_stack_id.IsValid() && cur_parent_id.IsValid() &&
234 m_parent_stack_id == cur_parent_id)
235 frame_order = eFrameCompareSameParent;
236 else
237 frame_order = eFrameCompareOlder;
238 }
239 return frame_order;
240 }
241
StopOthers()242 bool ThreadPlanStepRange::StopOthers() {
243 switch (m_stop_others) {
244 case lldb::eOnlyThisThread:
245 return true;
246 case lldb::eOnlyDuringStepping:
247 // If there is a call in the range of the next branch breakpoint,
248 // then we should always run all threads, since a call can execute
249 // arbitrary code which might for instance take a lock that's held
250 // by another thread.
251 return !m_found_calls;
252 case lldb::eAllThreads:
253 return false;
254 }
255 llvm_unreachable("Unhandled run mode!");
256 }
257
GetInstructionsForAddress(lldb::addr_t addr,size_t & range_index,size_t & insn_offset)258 InstructionList *ThreadPlanStepRange::GetInstructionsForAddress(
259 lldb::addr_t addr, size_t &range_index, size_t &insn_offset) {
260 size_t num_ranges = m_address_ranges.size();
261 for (size_t i = 0; i < num_ranges; i++) {
262 if (m_address_ranges[i].ContainsLoadAddress(addr, &GetTarget())) {
263 // Some joker added a zero size range to the stepping range...
264 if (m_address_ranges[i].GetByteSize() == 0)
265 return nullptr;
266
267 if (!m_instruction_ranges[i]) {
268 // Disassemble the address range given:
269 const char *plugin_name = nullptr;
270 const char *flavor = nullptr;
271 const char *cpu = nullptr;
272 const char *features = nullptr;
273 m_instruction_ranges[i] = Disassembler::DisassembleRange(
274 GetTarget().GetArchitecture(), plugin_name, flavor, cpu, features,
275 GetTarget(), m_address_ranges[i]);
276 }
277 if (!m_instruction_ranges[i])
278 return nullptr;
279 else {
280 // Find where we are in the instruction list as well. If we aren't at
281 // an instruction, return nullptr. In this case, we're probably lost,
282 // and shouldn't try to do anything fancy.
283
284 insn_offset =
285 m_instruction_ranges[i]
286 ->GetInstructionList()
287 .GetIndexOfInstructionAtLoadAddress(addr, GetTarget());
288 if (insn_offset == UINT32_MAX)
289 return nullptr;
290 else {
291 range_index = i;
292 return &m_instruction_ranges[i]->GetInstructionList();
293 }
294 }
295 }
296 }
297 return nullptr;
298 }
299
IsNextBranchBreakpointStop(StopInfoSP stop_info_sp)300 bool ThreadPlanStepRange::IsNextBranchBreakpointStop(StopInfoSP stop_info_sp) {
301 if (!m_next_branch_bp_sp)
302 return false;
303
304 break_id_t bp_site_id = stop_info_sp->GetValue();
305 BreakpointSiteSP bp_site_sp =
306 m_process.GetBreakpointSiteList().FindByID(bp_site_id);
307 if (!bp_site_sp)
308 return false;
309 else if (!bp_site_sp->IsBreakpointAtThisSite(m_next_branch_bp_sp->GetID()))
310 return false;
311 return true;
312 }
313
ClearNextBranchBreakpoint()314 void ThreadPlanStepRange::ClearNextBranchBreakpoint() {
315 if (m_next_branch_bp_sp) {
316 Log *log = GetLog(LLDBLog::Step);
317 LLDB_LOGF(log, "Removing next branch breakpoint: %d.",
318 m_next_branch_bp_sp->GetID());
319 GetTarget().RemoveBreakpointByID(m_next_branch_bp_sp->GetID());
320 m_next_branch_bp_sp.reset();
321 m_could_not_resolve_hw_bp = false;
322 m_found_calls = false;
323 }
324 }
325
ClearNextBranchBreakpointExplainedStop()326 void ThreadPlanStepRange::ClearNextBranchBreakpointExplainedStop() {
327 if (IsNextBranchBreakpointStop(GetPrivateStopInfo()))
328 ClearNextBranchBreakpoint();
329 }
330
SetNextBranchBreakpoint()331 bool ThreadPlanStepRange::SetNextBranchBreakpoint() {
332 if (m_next_branch_bp_sp)
333 return true;
334
335 Log *log = GetLog(LLDBLog::Step);
336 // Stepping through ranges using breakpoints doesn't work yet, but with this
337 // off we fall back to instruction single stepping.
338 if (!m_use_fast_step)
339 return false;
340
341 // clear the m_found_calls, we'll rediscover it for this range.
342 m_found_calls = false;
343
344 lldb::addr_t cur_addr = GetThread().GetRegisterContext()->GetPC();
345 // Find the current address in our address ranges, and fetch the disassembly
346 // if we haven't already:
347 size_t pc_index;
348 size_t range_index;
349 InstructionList *instructions =
350 GetInstructionsForAddress(cur_addr, range_index, pc_index);
351 if (instructions == nullptr)
352 return false;
353 else {
354 const bool ignore_calls = GetKind() == eKindStepOverRange;
355 uint32_t branch_index = instructions->GetIndexOfNextBranchInstruction(
356 pc_index, ignore_calls, &m_found_calls);
357 Address run_to_address;
358
359 // If we didn't find a branch, run to the end of the range.
360 if (branch_index == UINT32_MAX) {
361 uint32_t last_index = instructions->GetSize() - 1;
362 if (last_index - pc_index > 1) {
363 InstructionSP last_inst =
364 instructions->GetInstructionAtIndex(last_index);
365 size_t last_inst_size = last_inst->GetOpcode().GetByteSize();
366 run_to_address = last_inst->GetAddress();
367 run_to_address.Slide(last_inst_size);
368 }
369 } else if (branch_index - pc_index > 1) {
370 run_to_address =
371 instructions->GetInstructionAtIndex(branch_index)->GetAddress();
372 }
373 if (branch_index == pc_index)
374 LLDB_LOGF(log, "ThreadPlanStepRange::SetNextBranchBreakpoint - skipping "
375 "because current is branch instruction");
376 if (run_to_address.IsValid()) {
377 const bool is_internal = true;
378 m_next_branch_bp_sp =
379 GetTarget().CreateBreakpoint(run_to_address, is_internal, false);
380 if (m_next_branch_bp_sp) {
381
382 if (m_next_branch_bp_sp->IsHardware() &&
383 !m_next_branch_bp_sp->HasResolvedLocations())
384 m_could_not_resolve_hw_bp = true;
385
386 BreakpointLocationSP bp_loc =
387 m_next_branch_bp_sp->GetLocationAtIndex(0);
388 if (log) {
389 lldb::break_id_t bp_site_id = LLDB_INVALID_BREAK_ID;
390 if (bp_loc) {
391 BreakpointSiteSP bp_site = bp_loc->GetBreakpointSite();
392 if (bp_site) {
393 bp_site_id = bp_site->GetID();
394 }
395 }
396 LLDB_LOGF(log,
397 "ThreadPlanStepRange::SetNextBranchBreakpoint - Setting "
398 "breakpoint %d (site %d) to run to address 0x%" PRIx64,
399 m_next_branch_bp_sp->GetID(), bp_site_id,
400 run_to_address.GetLoadAddress(&m_process.GetTarget()));
401 }
402 // The "next branch breakpoint might land on a virtual inlined call
403 // stack. If that's true, we should always stop at the top of the
404 // inlined call stack. Only virtual steps should walk deeper into the
405 // inlined call stack.
406 Block *block = run_to_address.CalculateSymbolContextBlock();
407 if (bp_loc && block) {
408 LineEntry top_most_line_entry;
409 lldb::addr_t run_to_addr = run_to_address.GetFileAddress();
410 for (Block *inlined_parent = block->GetContainingInlinedBlock();
411 inlined_parent;
412 inlined_parent = inlined_parent->GetInlinedParent()) {
413 AddressRange range;
414 if (!inlined_parent->GetRangeContainingAddress(run_to_address,
415 range))
416 break;
417 Address range_start_address = range.GetBaseAddress();
418 // Only compare addresses here, we may have different symbol
419 // contexts (for virtual inlined stacks), but we just want to know
420 // that they are all at the same address.
421 if (range_start_address.GetFileAddress() != run_to_addr)
422 break;
423 const InlineFunctionInfo *inline_info =
424 inlined_parent->GetInlinedFunctionInfo();
425 if (!inline_info)
426 break;
427 const Declaration &call_site = inline_info->GetCallSite();
428 top_most_line_entry.line = call_site.GetLine();
429 top_most_line_entry.column = call_site.GetColumn();
430 FileSpec call_site_file_spec = call_site.GetFile();
431 top_most_line_entry.original_file_sp.reset(
432 new SupportFile(call_site_file_spec));
433 top_most_line_entry.range = range;
434 top_most_line_entry.file_sp.reset();
435 top_most_line_entry.ApplyFileMappings(
436 GetThread().CalculateTarget());
437 if (!top_most_line_entry.file_sp)
438 top_most_line_entry.file_sp =
439 top_most_line_entry.original_file_sp;
440 }
441 if (top_most_line_entry.IsValid()) {
442 LLDB_LOG(log, "Setting preferred line entry: {0}:{1}",
443 top_most_line_entry.GetFile(), top_most_line_entry.line);
444 bp_loc->SetPreferredLineEntry(top_most_line_entry);
445 }
446 }
447 m_next_branch_bp_sp->SetThreadID(m_tid);
448 m_next_branch_bp_sp->SetBreakpointKind("next-branch-location");
449
450 return true;
451 } else
452 return false;
453 } else
454 LLDB_LOGF(log, "ThreadPlanStepRange::SetNextBranchBreakpoint - skipping "
455 "invalid run_to_address");
456 }
457 return false;
458 }
459
NextRangeBreakpointExplainsStop(lldb::StopInfoSP stop_info_sp)460 bool ThreadPlanStepRange::NextRangeBreakpointExplainsStop(
461 lldb::StopInfoSP stop_info_sp) {
462 if (!IsNextBranchBreakpointStop(stop_info_sp))
463 return false;
464
465 break_id_t bp_site_id = stop_info_sp->GetValue();
466 BreakpointSiteSP bp_site_sp =
467 m_process.GetBreakpointSiteList().FindByID(bp_site_id);
468 if (!bp_site_sp)
469 return false;
470
471 // If we've hit the next branch breakpoint, then clear it.
472 size_t num_constituents = bp_site_sp->GetNumberOfConstituents();
473 bool explains_stop = true;
474 // If all the constituents are internal, then we are probably just stepping
475 // over this range from multiple threads, or multiple frames, so we want to
476 // continue. If one is not internal, then we should not explain the stop,
477 // and let the user breakpoint handle the stop.
478 for (size_t i = 0; i < num_constituents; i++) {
479 if (!bp_site_sp->GetConstituentAtIndex(i)->GetBreakpoint().IsInternal()) {
480 explains_stop = false;
481 break;
482 }
483 }
484 Log *log = GetLog(LLDBLog::Step);
485 LLDB_LOGF(log,
486 "ThreadPlanStepRange::NextRangeBreakpointExplainsStop - Hit "
487 "next range breakpoint which has %" PRIu64
488 " constituents - explains stop: %u.",
489 (uint64_t)num_constituents, explains_stop);
490 return explains_stop;
491 }
492
WillStop()493 bool ThreadPlanStepRange::WillStop() { return true; }
494
GetPlanRunState()495 StateType ThreadPlanStepRange::GetPlanRunState() {
496 if (m_next_branch_bp_sp)
497 return eStateRunning;
498 else
499 return eStateStepping;
500 }
501
MischiefManaged()502 bool ThreadPlanStepRange::MischiefManaged() {
503 // If we have pushed some plans between ShouldStop & MischiefManaged, then
504 // we're not done...
505 // I do this check first because we might have stepped somewhere that will
506 // fool InRange into
507 // thinking it needs to step past the end of that line. This happens, for
508 // instance, when stepping over inlined code that is in the middle of the
509 // current line.
510
511 if (!m_no_more_plans)
512 return false;
513
514 bool done = true;
515 if (!IsPlanComplete()) {
516 if (InRange()) {
517 done = false;
518 } else {
519 FrameComparison frame_order = CompareCurrentFrameToStartFrame();
520 done = (frame_order != eFrameCompareOlder) ? m_no_more_plans : true;
521 }
522 }
523
524 if (done) {
525 Log *log = GetLog(LLDBLog::Step);
526 LLDB_LOGF(log, "Completed step through range plan.");
527 ClearNextBranchBreakpoint();
528 ThreadPlan::MischiefManaged();
529 return true;
530 } else {
531 return false;
532 }
533 }
534
IsPlanStale()535 bool ThreadPlanStepRange::IsPlanStale() {
536 Log *log = GetLog(LLDBLog::Step);
537 FrameComparison frame_order = CompareCurrentFrameToStartFrame();
538
539 if (frame_order == eFrameCompareOlder) {
540 if (log) {
541 LLDB_LOGF(log, "ThreadPlanStepRange::IsPlanStale returning true, we've "
542 "stepped out.");
543 }
544 return true;
545 } else if (frame_order == eFrameCompareEqual && InSymbol()) {
546 // If we are not in a place we should step through, we've gotten stale. One
547 // tricky bit here is that some stubs don't push a frame, so we should.
548 // check that we are in the same symbol.
549 if (!InRange()) {
550 // Set plan Complete when we reach next instruction just after the range
551 lldb::addr_t addr = GetThread().GetRegisterContext()->GetPC() - 1;
552 size_t num_ranges = m_address_ranges.size();
553 for (size_t i = 0; i < num_ranges; i++) {
554 bool in_range =
555 m_address_ranges[i].ContainsLoadAddress(addr, &GetTarget());
556 if (in_range) {
557 SetPlanComplete();
558 }
559 }
560 return true;
561 }
562 }
563 return false;
564 }
565