1 //===-- ThreadPlanCallFunction.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/ThreadPlanCallFunction.h"
10 #include "lldb/Breakpoint/Breakpoint.h"
11 #include "lldb/Breakpoint/BreakpointLocation.h"
12 #include "lldb/Core/Address.h"
13 #include "lldb/Core/DumpRegisterValue.h"
14 #include "lldb/Core/Module.h"
15 #include "lldb/Symbol/ObjectFile.h"
16 #include "lldb/Target/ABI.h"
17 #include "lldb/Target/LanguageRuntime.h"
18 #include "lldb/Target/Process.h"
19 #include "lldb/Target/RegisterContext.h"
20 #include "lldb/Target/StopInfo.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Target/Thread.h"
23 #include "lldb/Target/ThreadPlanRunToAddress.h"
24 #include "lldb/Utility/Log.h"
25 #include "lldb/Utility/Stream.h"
26 
27 #include <memory>
28 
29 using namespace lldb;
30 using namespace lldb_private;
31 
32 // ThreadPlanCallFunction: Plan to call a single function
33 bool ThreadPlanCallFunction::ConstructorSetup(
34     Thread &thread, ABI *&abi, lldb::addr_t &start_load_addr,
35     lldb::addr_t &function_load_addr) {
36   SetIsMasterPlan(true);
37   SetOkayToDiscard(false);
38   SetPrivate(true);
39 
40   ProcessSP process_sp(thread.GetProcess());
41   if (!process_sp)
42     return false;
43 
44   abi = process_sp->GetABI().get();
45 
46   if (!abi)
47     return false;
48 
49   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_STEP));
50 
51   SetBreakpoints();
52 
53   m_function_sp = thread.GetRegisterContext()->GetSP() - abi->GetRedZoneSize();
54   // If we can't read memory at the point of the process where we are planning
55   // to put our function, we're not going to get any further...
56   Status error;
57   process_sp->ReadUnsignedIntegerFromMemory(m_function_sp, 4, 0, error);
58   if (!error.Success()) {
59     m_constructor_errors.Printf(
60         "Trying to put the stack in unreadable memory at: 0x%" PRIx64 ".",
61         m_function_sp);
62     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
63               m_constructor_errors.GetData());
64     return false;
65   }
66 
67   llvm::Expected<Address> start_address = GetTarget().GetEntryPointAddress();
68   if (!start_address) {
69     m_constructor_errors.Printf(
70         "%s", llvm::toString(start_address.takeError()).c_str());
71     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
72               m_constructor_errors.GetData());
73     return false;
74   }
75 
76   m_start_addr = *start_address;
77   start_load_addr = m_start_addr.GetLoadAddress(&GetTarget());
78 
79   // Checkpoint the thread state so we can restore it later.
80   if (log && log->GetVerbose())
81     ReportRegisterState("About to checkpoint thread before function call.  "
82                         "Original register state was:");
83 
84   if (!thread.CheckpointThreadState(m_stored_thread_state)) {
85     m_constructor_errors.Printf("Setting up ThreadPlanCallFunction, failed to "
86                                 "checkpoint thread state.");
87     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
88               m_constructor_errors.GetData());
89     return false;
90   }
91   function_load_addr = m_function_addr.GetLoadAddress(&GetTarget());
92 
93   return true;
94 }
95 
96 ThreadPlanCallFunction::ThreadPlanCallFunction(
97     Thread &thread, const Address &function, const CompilerType &return_type,
98     llvm::ArrayRef<addr_t> args, const EvaluateExpressionOptions &options)
99     : ThreadPlan(ThreadPlan::eKindCallFunction, "Call function plan", thread,
100                  eVoteNoOpinion, eVoteNoOpinion),
101       m_valid(false), m_stop_other_threads(options.GetStopOthers()),
102       m_unwind_on_error(options.DoesUnwindOnError()),
103       m_ignore_breakpoints(options.DoesIgnoreBreakpoints()),
104       m_debug_execution(options.GetDebug()),
105       m_trap_exceptions(options.GetTrapExceptions()), m_function_addr(function),
106       m_function_sp(0), m_takedown_done(false),
107       m_should_clear_objc_exception_bp(false),
108       m_should_clear_cxx_exception_bp(false),
109       m_stop_address(LLDB_INVALID_ADDRESS), m_return_type(return_type) {
110   lldb::addr_t start_load_addr = LLDB_INVALID_ADDRESS;
111   lldb::addr_t function_load_addr = LLDB_INVALID_ADDRESS;
112   ABI *abi = nullptr;
113 
114   if (!ConstructorSetup(thread, abi, start_load_addr, function_load_addr))
115     return;
116 
117   if (!abi->PrepareTrivialCall(thread, m_function_sp, function_load_addr,
118                                start_load_addr, args))
119     return;
120 
121   ReportRegisterState("Function call was set up.  Register state was:");
122 
123   m_valid = true;
124 }
125 
126 ThreadPlanCallFunction::ThreadPlanCallFunction(
127     Thread &thread, const Address &function,
128     const EvaluateExpressionOptions &options)
129     : ThreadPlan(ThreadPlan::eKindCallFunction, "Call function plan", thread,
130                  eVoteNoOpinion, eVoteNoOpinion),
131       m_valid(false), m_stop_other_threads(options.GetStopOthers()),
132       m_unwind_on_error(options.DoesUnwindOnError()),
133       m_ignore_breakpoints(options.DoesIgnoreBreakpoints()),
134       m_debug_execution(options.GetDebug()),
135       m_trap_exceptions(options.GetTrapExceptions()), m_function_addr(function),
136       m_function_sp(0), m_takedown_done(false),
137       m_should_clear_objc_exception_bp(false),
138       m_should_clear_cxx_exception_bp(false),
139       m_stop_address(LLDB_INVALID_ADDRESS), m_return_type(CompilerType()) {}
140 
141 ThreadPlanCallFunction::~ThreadPlanCallFunction() {
142   DoTakedown(PlanSucceeded());
143 }
144 
145 void ThreadPlanCallFunction::ReportRegisterState(const char *message) {
146   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
147   if (log && log->GetVerbose()) {
148     StreamString strm;
149     RegisterContext *reg_ctx = m_thread.GetRegisterContext().get();
150 
151     log->PutCString(message);
152 
153     RegisterValue reg_value;
154 
155     for (uint32_t reg_idx = 0, num_registers = reg_ctx->GetRegisterCount();
156          reg_idx < num_registers; ++reg_idx) {
157       const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoAtIndex(reg_idx);
158       if (reg_ctx->ReadRegister(reg_info, reg_value)) {
159         DumpRegisterValue(reg_value, &strm, reg_info, true, false,
160                           eFormatDefault);
161         strm.EOL();
162       }
163     }
164     log->PutString(strm.GetString());
165   }
166 }
167 
168 void ThreadPlanCallFunction::DoTakedown(bool success) {
169   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_STEP));
170 
171   if (!m_valid) {
172     // Don't call DoTakedown if we were never valid to begin with.
173     LLDB_LOGF(log,
174               "ThreadPlanCallFunction(%p): Log called on "
175               "ThreadPlanCallFunction that was never valid.",
176               static_cast<void *>(this));
177     return;
178   }
179 
180   if (!m_takedown_done) {
181     if (success) {
182       SetReturnValue();
183     }
184     LLDB_LOGF(log,
185               "ThreadPlanCallFunction(%p): DoTakedown called for thread "
186               "0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
187               static_cast<void *>(this), m_thread.GetID(), m_valid,
188               IsPlanComplete());
189     m_takedown_done = true;
190     m_stop_address =
191         m_thread.GetStackFrameAtIndex(0)->GetRegisterContext()->GetPC();
192     m_real_stop_info_sp = GetPrivateStopInfo();
193     if (!m_thread.RestoreRegisterStateFromCheckpoint(m_stored_thread_state)) {
194       LLDB_LOGF(log,
195                 "ThreadPlanCallFunction(%p): DoTakedown failed to restore "
196                 "register state",
197                 static_cast<void *>(this));
198     }
199     SetPlanComplete(success);
200     ClearBreakpoints();
201     if (log && log->GetVerbose())
202       ReportRegisterState("Restoring thread state after function call.  "
203                           "Restored register state:");
204   } else {
205     LLDB_LOGF(log,
206               "ThreadPlanCallFunction(%p): DoTakedown called as no-op for "
207               "thread 0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
208               static_cast<void *>(this), m_thread.GetID(), m_valid,
209               IsPlanComplete());
210   }
211 }
212 
213 void ThreadPlanCallFunction::WillPop() { DoTakedown(PlanSucceeded()); }
214 
215 void ThreadPlanCallFunction::GetDescription(Stream *s, DescriptionLevel level) {
216   if (level == eDescriptionLevelBrief) {
217     s->Printf("Function call thread plan");
218   } else {
219     TargetSP target_sp(m_thread.CalculateTarget());
220     s->Printf("Thread plan to call 0x%" PRIx64,
221               m_function_addr.GetLoadAddress(target_sp.get()));
222   }
223 }
224 
225 bool ThreadPlanCallFunction::ValidatePlan(Stream *error) {
226   if (!m_valid) {
227     if (error) {
228       if (m_constructor_errors.GetSize() > 0)
229         error->PutCString(m_constructor_errors.GetString());
230       else
231         error->PutCString("Unknown error");
232     }
233     return false;
234   }
235 
236   return true;
237 }
238 
239 Vote ThreadPlanCallFunction::ShouldReportStop(Event *event_ptr) {
240   if (m_takedown_done || IsPlanComplete())
241     return eVoteYes;
242   else
243     return ThreadPlan::ShouldReportStop(event_ptr);
244 }
245 
246 bool ThreadPlanCallFunction::DoPlanExplainsStop(Event *event_ptr) {
247   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_STEP |
248                                                   LIBLLDB_LOG_PROCESS));
249   m_real_stop_info_sp = GetPrivateStopInfo();
250 
251   // If our subplan knows why we stopped, even if it's done (which would
252   // forward the question to us) we answer yes.
253   if (m_subplan_sp && m_subplan_sp->PlanExplainsStop(event_ptr)) {
254     SetPlanComplete();
255     return true;
256   }
257 
258   // Check if the breakpoint is one of ours.
259 
260   StopReason stop_reason;
261   if (!m_real_stop_info_sp)
262     stop_reason = eStopReasonNone;
263   else
264     stop_reason = m_real_stop_info_sp->GetStopReason();
265   LLDB_LOGF(log,
266             "ThreadPlanCallFunction::PlanExplainsStop: Got stop reason - %s.",
267             Thread::StopReasonAsCString(stop_reason));
268 
269   if (stop_reason == eStopReasonBreakpoint && BreakpointsExplainStop())
270     return true;
271 
272   // One more quirk here.  If this event was from Halt interrupting the target,
273   // then we should not consider ourselves complete.  Return true to
274   // acknowledge the stop.
275   if (Process::ProcessEventData::GetInterruptedFromEvent(event_ptr)) {
276     LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: The event is an "
277                    "Interrupt, returning true.");
278     return true;
279   }
280   // We control breakpoints separately from other "stop reasons."  So first,
281   // check the case where we stopped for an internal breakpoint, in that case,
282   // continue on. If it is not an internal breakpoint, consult
283   // m_ignore_breakpoints.
284 
285   if (stop_reason == eStopReasonBreakpoint) {
286     ProcessSP process_sp(m_thread.CalculateProcess());
287     uint64_t break_site_id = m_real_stop_info_sp->GetValue();
288     BreakpointSiteSP bp_site_sp;
289     if (process_sp)
290       bp_site_sp = process_sp->GetBreakpointSiteList().FindByID(break_site_id);
291     if (bp_site_sp) {
292       uint32_t num_owners = bp_site_sp->GetNumberOfOwners();
293       bool is_internal = true;
294       for (uint32_t i = 0; i < num_owners; i++) {
295         Breakpoint &bp = bp_site_sp->GetOwnerAtIndex(i)->GetBreakpoint();
296         LLDB_LOGF(log,
297                   "ThreadPlanCallFunction::PlanExplainsStop: hit "
298                   "breakpoint %d while calling function",
299                   bp.GetID());
300 
301         if (!bp.IsInternal()) {
302           is_internal = false;
303           break;
304         }
305       }
306       if (is_internal) {
307         LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop hit an "
308                        "internal breakpoint, not stopping.");
309         return false;
310       }
311     }
312 
313     if (m_ignore_breakpoints) {
314       LLDB_LOGF(log,
315                 "ThreadPlanCallFunction::PlanExplainsStop: we are ignoring "
316                 "breakpoints, overriding breakpoint stop info ShouldStop, "
317                 "returning true");
318       m_real_stop_info_sp->OverrideShouldStop(false);
319       return true;
320     } else {
321       LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: we are not "
322                      "ignoring breakpoints, overriding breakpoint stop info "
323                      "ShouldStop, returning true");
324       m_real_stop_info_sp->OverrideShouldStop(true);
325       return false;
326     }
327   } else if (!m_unwind_on_error) {
328     // If we don't want to discard this plan, than any stop we don't understand
329     // should be propagated up the stack.
330     return false;
331   } else {
332     // If the subplan is running, any crashes are attributable to us. If we
333     // want to discard the plan, then we say we explain the stop but if we are
334     // going to be discarded, let whoever is above us explain the stop. But
335     // don't discard the plan if the stop would restart itself (for instance if
336     // it is a signal that is set not to stop.  Check that here first.  We just
337     // say we explain the stop but aren't done and everything will continue on
338     // from there.
339 
340     if (m_real_stop_info_sp &&
341         m_real_stop_info_sp->ShouldStopSynchronous(event_ptr)) {
342       SetPlanComplete(false);
343       return m_subplan_sp ? m_unwind_on_error : false;
344     } else
345       return true;
346   }
347 }
348 
349 bool ThreadPlanCallFunction::ShouldStop(Event *event_ptr) {
350   // We do some computation in DoPlanExplainsStop that may or may not set the
351   // plan as complete. We need to do that here to make sure our state is
352   // correct.
353   DoPlanExplainsStop(event_ptr);
354 
355   if (IsPlanComplete()) {
356     ReportRegisterState("Function completed.  Register state was:");
357     return true;
358   } else {
359     return false;
360   }
361 }
362 
363 bool ThreadPlanCallFunction::StopOthers() { return m_stop_other_threads; }
364 
365 StateType ThreadPlanCallFunction::GetPlanRunState() { return eStateRunning; }
366 
367 void ThreadPlanCallFunction::DidPush() {
368   //#define SINGLE_STEP_EXPRESSIONS
369 
370   // Now set the thread state to "no reason" so we don't run with whatever
371   // signal was outstanding... Wait till the plan is pushed so we aren't
372   // changing the stop info till we're about to run.
373 
374   GetThread().SetStopInfoToNothing();
375 
376 #ifndef SINGLE_STEP_EXPRESSIONS
377   m_subplan_sp = std::make_shared<ThreadPlanRunToAddress>(
378       m_thread, m_start_addr, m_stop_other_threads);
379 
380   m_thread.QueueThreadPlan(m_subplan_sp, false);
381   m_subplan_sp->SetPrivate(true);
382 #endif
383 }
384 
385 bool ThreadPlanCallFunction::WillStop() { return true; }
386 
387 bool ThreadPlanCallFunction::MischiefManaged() {
388   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
389 
390   if (IsPlanComplete()) {
391     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): Completed call function plan.",
392               static_cast<void *>(this));
393 
394     ThreadPlan::MischiefManaged();
395     return true;
396   } else {
397     return false;
398   }
399 }
400 
401 void ThreadPlanCallFunction::SetBreakpoints() {
402   ProcessSP process_sp(m_thread.CalculateProcess());
403   if (m_trap_exceptions && process_sp) {
404     m_cxx_language_runtime =
405         process_sp->GetLanguageRuntime(eLanguageTypeC_plus_plus);
406     m_objc_language_runtime = process_sp->GetLanguageRuntime(eLanguageTypeObjC);
407 
408     if (m_cxx_language_runtime) {
409       m_should_clear_cxx_exception_bp =
410           !m_cxx_language_runtime->ExceptionBreakpointsAreSet();
411       m_cxx_language_runtime->SetExceptionBreakpoints();
412     }
413     if (m_objc_language_runtime) {
414       m_should_clear_objc_exception_bp =
415           !m_objc_language_runtime->ExceptionBreakpointsAreSet();
416       m_objc_language_runtime->SetExceptionBreakpoints();
417     }
418   }
419 }
420 
421 void ThreadPlanCallFunction::ClearBreakpoints() {
422   if (m_trap_exceptions) {
423     if (m_cxx_language_runtime && m_should_clear_cxx_exception_bp)
424       m_cxx_language_runtime->ClearExceptionBreakpoints();
425     if (m_objc_language_runtime && m_should_clear_objc_exception_bp)
426       m_objc_language_runtime->ClearExceptionBreakpoints();
427   }
428 }
429 
430 bool ThreadPlanCallFunction::BreakpointsExplainStop() {
431   StopInfoSP stop_info_sp = GetPrivateStopInfo();
432 
433   if (m_trap_exceptions) {
434     if ((m_cxx_language_runtime &&
435          m_cxx_language_runtime->ExceptionBreakpointsExplainStop(
436              stop_info_sp)) ||
437         (m_objc_language_runtime &&
438          m_objc_language_runtime->ExceptionBreakpointsExplainStop(
439              stop_info_sp))) {
440       Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_STEP));
441       LLDB_LOGF(log, "ThreadPlanCallFunction::BreakpointsExplainStop - Hit an "
442                      "exception breakpoint, setting plan complete.");
443 
444       SetPlanComplete(false);
445 
446       // If the user has set the ObjC language breakpoint, it would normally
447       // get priority over our internal catcher breakpoint, but in this case we
448       // can't let that happen, so force the ShouldStop here.
449       stop_info_sp->OverrideShouldStop(true);
450       return true;
451     }
452   }
453 
454   return false;
455 }
456 
457 void ThreadPlanCallFunction::SetStopOthers(bool new_value) {
458   m_subplan_sp->SetStopOthers(new_value);
459 }
460 
461 bool ThreadPlanCallFunction::RestoreThreadState() {
462   return GetThread().RestoreThreadStateFromCheckpoint(m_stored_thread_state);
463 }
464 
465 void ThreadPlanCallFunction::SetReturnValue() {
466   ProcessSP process_sp(m_thread.GetProcess());
467   const ABI *abi = process_sp ? process_sp->GetABI().get() : nullptr;
468   if (abi && m_return_type.IsValid()) {
469     const bool persistent = false;
470     m_return_valobj_sp =
471         abi->GetReturnValueObject(m_thread, m_return_type, persistent);
472   }
473 }
474