1 //===-- ThreadPlanCallFunction.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/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/LLDBLog.h"
25 #include "lldb/Utility/Log.h"
26 #include "lldb/Utility/Stream.h"
27 
28 #include <memory>
29 
30 using namespace lldb;
31 using namespace lldb_private;
32 
33 // ThreadPlanCallFunction: Plan to call a single function
34 bool ThreadPlanCallFunction::ConstructorSetup(
35     Thread &thread, ABI *&abi, lldb::addr_t &start_load_addr,
36     lldb::addr_t &function_load_addr) {
37   SetIsControllingPlan(true);
38   SetOkayToDiscard(false);
39   SetPrivate(true);
40 
41   ProcessSP process_sp(thread.GetProcess());
42   if (!process_sp)
43     return false;
44 
45   abi = process_sp->GetABI().get();
46 
47   if (!abi)
48     return false;
49 
50   Log *log = GetLog(LLDBLog::Step);
51 
52   SetBreakpoints();
53 
54   m_function_sp = thread.GetRegisterContext()->GetSP() - abi->GetRedZoneSize();
55   // If we can't read memory at the point of the process where we are planning
56   // to put our function, we're not going to get any further...
57   Status error;
58   process_sp->ReadUnsignedIntegerFromMemory(m_function_sp, 4, 0, error);
59   if (!error.Success()) {
60     m_constructor_errors.Printf(
61         "Trying to put the stack in unreadable memory at: 0x%" PRIx64 ".",
62         m_function_sp);
63     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
64               m_constructor_errors.GetData());
65     return false;
66   }
67 
68   llvm::Expected<Address> start_address = GetTarget().GetEntryPointAddress();
69   if (!start_address) {
70     m_constructor_errors.Printf(
71         "%s", llvm::toString(start_address.takeError()).c_str());
72     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
73               m_constructor_errors.GetData());
74     return false;
75   }
76 
77   m_start_addr = *start_address;
78   start_load_addr = m_start_addr.GetLoadAddress(&GetTarget());
79 
80   // Checkpoint the thread state so we can restore it later.
81   if (log && log->GetVerbose())
82     ReportRegisterState("About to checkpoint thread before function call.  "
83                         "Original register state was:");
84 
85   if (!thread.CheckpointThreadState(m_stored_thread_state)) {
86     m_constructor_errors.Printf("Setting up ThreadPlanCallFunction, failed to "
87                                 "checkpoint thread state.");
88     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): %s.", static_cast<void *>(this),
89               m_constructor_errors.GetData());
90     return false;
91   }
92   function_load_addr = m_function_addr.GetLoadAddress(&GetTarget());
93 
94   return true;
95 }
96 
97 ThreadPlanCallFunction::ThreadPlanCallFunction(
98     Thread &thread, const Address &function, const CompilerType &return_type,
99     llvm::ArrayRef<addr_t> args, const EvaluateExpressionOptions &options)
100     : ThreadPlan(ThreadPlan::eKindCallFunction, "Call function plan", thread,
101                  eVoteNoOpinion, eVoteNoOpinion),
102       m_valid(false), m_stop_other_threads(options.GetStopOthers()),
103       m_unwind_on_error(options.DoesUnwindOnError()),
104       m_ignore_breakpoints(options.DoesIgnoreBreakpoints()),
105       m_debug_execution(options.GetDebug()),
106       m_trap_exceptions(options.GetTrapExceptions()), m_function_addr(function),
107       m_start_addr(), m_function_sp(0), m_subplan_sp(),
108       m_cxx_language_runtime(nullptr), m_objc_language_runtime(nullptr),
109       m_stored_thread_state(), m_real_stop_info_sp(), m_constructor_errors(),
110       m_return_valobj_sp(), m_takedown_done(false),
111       m_should_clear_objc_exception_bp(false),
112       m_should_clear_cxx_exception_bp(false),
113       m_stop_address(LLDB_INVALID_ADDRESS), m_return_type(return_type) {
114   lldb::addr_t start_load_addr = LLDB_INVALID_ADDRESS;
115   lldb::addr_t function_load_addr = LLDB_INVALID_ADDRESS;
116   ABI *abi = nullptr;
117 
118   if (!ConstructorSetup(thread, abi, start_load_addr, function_load_addr))
119     return;
120 
121   if (!abi->PrepareTrivialCall(thread, m_function_sp, function_load_addr,
122                                start_load_addr, args))
123     return;
124 
125   ReportRegisterState("Function call was set up.  Register state was:");
126 
127   m_valid = true;
128 }
129 
130 ThreadPlanCallFunction::ThreadPlanCallFunction(
131     Thread &thread, const Address &function,
132     const EvaluateExpressionOptions &options)
133     : ThreadPlan(ThreadPlan::eKindCallFunction, "Call function plan", thread,
134                  eVoteNoOpinion, eVoteNoOpinion),
135       m_valid(false), m_stop_other_threads(options.GetStopOthers()),
136       m_unwind_on_error(options.DoesUnwindOnError()),
137       m_ignore_breakpoints(options.DoesIgnoreBreakpoints()),
138       m_debug_execution(options.GetDebug()),
139       m_trap_exceptions(options.GetTrapExceptions()), m_function_addr(function),
140       m_start_addr(), m_function_sp(0), m_subplan_sp(),
141       m_cxx_language_runtime(nullptr), m_objc_language_runtime(nullptr),
142       m_stored_thread_state(), m_real_stop_info_sp(), m_constructor_errors(),
143       m_return_valobj_sp(), m_takedown_done(false),
144       m_should_clear_objc_exception_bp(false),
145       m_should_clear_cxx_exception_bp(false),
146       m_stop_address(LLDB_INVALID_ADDRESS), m_return_type(CompilerType()) {}
147 
148 ThreadPlanCallFunction::~ThreadPlanCallFunction() {
149   DoTakedown(PlanSucceeded());
150 }
151 
152 void ThreadPlanCallFunction::ReportRegisterState(const char *message) {
153   Log *log = GetLog(LLDBLog::Step);
154   if (log && log->GetVerbose()) {
155     StreamString strm;
156     RegisterContext *reg_ctx = GetThread().GetRegisterContext().get();
157 
158     log->PutCString(message);
159 
160     RegisterValue reg_value;
161 
162     for (uint32_t reg_idx = 0, num_registers = reg_ctx->GetRegisterCount();
163          reg_idx < num_registers; ++reg_idx) {
164       const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoAtIndex(reg_idx);
165       if (reg_ctx->ReadRegister(reg_info, reg_value)) {
166         DumpRegisterValue(reg_value, &strm, reg_info, true, false,
167                           eFormatDefault);
168         strm.EOL();
169       }
170     }
171     log->PutString(strm.GetString());
172   }
173 }
174 
175 void ThreadPlanCallFunction::DoTakedown(bool success) {
176   Log *log = GetLog(LLDBLog::Step);
177 
178   if (!m_valid) {
179     // Don't call DoTakedown if we were never valid to begin with.
180     LLDB_LOGF(log,
181               "ThreadPlanCallFunction(%p): Log called on "
182               "ThreadPlanCallFunction that was never valid.",
183               static_cast<void *>(this));
184     return;
185   }
186 
187   if (!m_takedown_done) {
188     Thread &thread = GetThread();
189     if (success) {
190       SetReturnValue();
191     }
192     LLDB_LOGF(log,
193               "ThreadPlanCallFunction(%p): DoTakedown called for thread "
194               "0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
195               static_cast<void *>(this), m_tid, m_valid, IsPlanComplete());
196     m_takedown_done = true;
197     m_stop_address =
198         thread.GetStackFrameAtIndex(0)->GetRegisterContext()->GetPC();
199     m_real_stop_info_sp = GetPrivateStopInfo();
200     if (!thread.RestoreRegisterStateFromCheckpoint(m_stored_thread_state)) {
201       LLDB_LOGF(log,
202                 "ThreadPlanCallFunction(%p): DoTakedown failed to restore "
203                 "register state",
204                 static_cast<void *>(this));
205     }
206     SetPlanComplete(success);
207     ClearBreakpoints();
208     if (log && log->GetVerbose())
209       ReportRegisterState("Restoring thread state after function call.  "
210                           "Restored register state:");
211   } else {
212     LLDB_LOGF(log,
213               "ThreadPlanCallFunction(%p): DoTakedown called as no-op for "
214               "thread 0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
215               static_cast<void *>(this), m_tid, m_valid, IsPlanComplete());
216   }
217 }
218 
219 void ThreadPlanCallFunction::DidPop() { DoTakedown(PlanSucceeded()); }
220 
221 void ThreadPlanCallFunction::GetDescription(Stream *s, DescriptionLevel level) {
222   if (level == eDescriptionLevelBrief) {
223     s->Printf("Function call thread plan");
224   } else {
225     s->Printf("Thread plan to call 0x%" PRIx64,
226               m_function_addr.GetLoadAddress(&GetTarget()));
227   }
228 }
229 
230 bool ThreadPlanCallFunction::ValidatePlan(Stream *error) {
231   if (!m_valid) {
232     if (error) {
233       if (m_constructor_errors.GetSize() > 0)
234         error->PutCString(m_constructor_errors.GetString());
235       else
236         error->PutCString("Unknown error");
237     }
238     return false;
239   }
240 
241   return true;
242 }
243 
244 Vote ThreadPlanCallFunction::ShouldReportStop(Event *event_ptr) {
245   if (m_takedown_done || IsPlanComplete())
246     return eVoteYes;
247   else
248     return ThreadPlan::ShouldReportStop(event_ptr);
249 }
250 
251 bool ThreadPlanCallFunction::DoPlanExplainsStop(Event *event_ptr) {
252   Log *log(GetLog(LLDBLog::Step | LLDBLog::Process));
253   m_real_stop_info_sp = GetPrivateStopInfo();
254 
255   // If our subplan knows why we stopped, even if it's done (which would
256   // forward the question to us) we answer yes.
257   if (m_subplan_sp && m_subplan_sp->PlanExplainsStop(event_ptr)) {
258     SetPlanComplete();
259     return true;
260   }
261 
262   // Check if the breakpoint is one of ours.
263 
264   StopReason stop_reason;
265   if (!m_real_stop_info_sp)
266     stop_reason = eStopReasonNone;
267   else
268     stop_reason = m_real_stop_info_sp->GetStopReason();
269   LLDB_LOG(log,
270            "ThreadPlanCallFunction::PlanExplainsStop: Got stop reason - {0}.",
271            Thread::StopReasonAsString(stop_reason));
272 
273   if (stop_reason == eStopReasonBreakpoint && BreakpointsExplainStop())
274     return true;
275 
276   // One more quirk here.  If this event was from Halt interrupting the target,
277   // then we should not consider ourselves complete.  Return true to
278   // acknowledge the stop.
279   if (Process::ProcessEventData::GetInterruptedFromEvent(event_ptr)) {
280     LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: The event is an "
281                    "Interrupt, returning true.");
282     return true;
283   }
284   // We control breakpoints separately from other "stop reasons."  So first,
285   // check the case where we stopped for an internal breakpoint, in that case,
286   // continue on. If it is not an internal breakpoint, consult
287   // m_ignore_breakpoints.
288 
289   if (stop_reason == eStopReasonBreakpoint) {
290     uint64_t break_site_id = m_real_stop_info_sp->GetValue();
291     BreakpointSiteSP bp_site_sp;
292     bp_site_sp = m_process.GetBreakpointSiteList().FindByID(break_site_id);
293     if (bp_site_sp) {
294       uint32_t num_owners = bp_site_sp->GetNumberOfOwners();
295       bool is_internal = true;
296       for (uint32_t i = 0; i < num_owners; i++) {
297         Breakpoint &bp = bp_site_sp->GetOwnerAtIndex(i)->GetBreakpoint();
298         LLDB_LOGF(log,
299                   "ThreadPlanCallFunction::PlanExplainsStop: hit "
300                   "breakpoint %d while calling function",
301                   bp.GetID());
302 
303         if (!bp.IsInternal()) {
304           is_internal = false;
305           break;
306         }
307       }
308       if (is_internal) {
309         LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop hit an "
310                        "internal breakpoint, not stopping.");
311         return false;
312       }
313     }
314 
315     if (m_ignore_breakpoints) {
316       LLDB_LOGF(log,
317                 "ThreadPlanCallFunction::PlanExplainsStop: we are ignoring "
318                 "breakpoints, overriding breakpoint stop info ShouldStop, "
319                 "returning true");
320       m_real_stop_info_sp->OverrideShouldStop(false);
321       return true;
322     } else {
323       LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: we are not "
324                      "ignoring breakpoints, overriding breakpoint stop info "
325                      "ShouldStop, returning true");
326       m_real_stop_info_sp->OverrideShouldStop(true);
327       return false;
328     }
329   } else if (!m_unwind_on_error) {
330     // If we don't want to discard this plan, than any stop we don't understand
331     // should be propagated up the stack.
332     return false;
333   } else {
334     // If the subplan is running, any crashes are attributable to us. If we
335     // want to discard the plan, then we say we explain the stop but if we are
336     // going to be discarded, let whoever is above us explain the stop. But
337     // don't discard the plan if the stop would restart itself (for instance if
338     // it is a signal that is set not to stop.  Check that here first.  We just
339     // say we explain the stop but aren't done and everything will continue on
340     // from there.
341 
342     if (m_real_stop_info_sp &&
343         m_real_stop_info_sp->ShouldStopSynchronous(event_ptr)) {
344       SetPlanComplete(false);
345       return m_subplan_sp ? m_unwind_on_error : false;
346     } else
347       return true;
348   }
349 }
350 
351 bool ThreadPlanCallFunction::ShouldStop(Event *event_ptr) {
352   // We do some computation in DoPlanExplainsStop that may or may not set the
353   // plan as complete. We need to do that here to make sure our state is
354   // correct.
355   DoPlanExplainsStop(event_ptr);
356 
357   if (IsPlanComplete()) {
358     ReportRegisterState("Function completed.  Register state was:");
359     return true;
360   } else {
361     return false;
362   }
363 }
364 
365 bool ThreadPlanCallFunction::StopOthers() { return m_stop_other_threads; }
366 
367 StateType ThreadPlanCallFunction::GetPlanRunState() { return eStateRunning; }
368 
369 void ThreadPlanCallFunction::DidPush() {
370   //#define SINGLE_STEP_EXPRESSIONS
371 
372   // Now set the thread state to "no reason" so we don't run with whatever
373   // signal was outstanding... Wait till the plan is pushed so we aren't
374   // changing the stop info till we're about to run.
375 
376   GetThread().SetStopInfoToNothing();
377 
378 #ifndef SINGLE_STEP_EXPRESSIONS
379   Thread &thread = GetThread();
380   m_subplan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, m_start_addr,
381                                                           m_stop_other_threads);
382 
383   thread.QueueThreadPlan(m_subplan_sp, false);
384   m_subplan_sp->SetPrivate(true);
385 #endif
386 }
387 
388 bool ThreadPlanCallFunction::WillStop() { return true; }
389 
390 bool ThreadPlanCallFunction::MischiefManaged() {
391   Log *log = GetLog(LLDBLog::Step);
392 
393   if (IsPlanComplete()) {
394     LLDB_LOGF(log, "ThreadPlanCallFunction(%p): Completed call function plan.",
395               static_cast<void *>(this));
396 
397     ThreadPlan::MischiefManaged();
398     return true;
399   } else {
400     return false;
401   }
402 }
403 
404 void ThreadPlanCallFunction::SetBreakpoints() {
405   if (m_trap_exceptions) {
406     m_cxx_language_runtime =
407         m_process.GetLanguageRuntime(eLanguageTypeC_plus_plus);
408     m_objc_language_runtime = m_process.GetLanguageRuntime(eLanguageTypeObjC);
409 
410     if (m_cxx_language_runtime) {
411       m_should_clear_cxx_exception_bp =
412           !m_cxx_language_runtime->ExceptionBreakpointsAreSet();
413       m_cxx_language_runtime->SetExceptionBreakpoints();
414     }
415     if (m_objc_language_runtime) {
416       m_should_clear_objc_exception_bp =
417           !m_objc_language_runtime->ExceptionBreakpointsAreSet();
418       m_objc_language_runtime->SetExceptionBreakpoints();
419     }
420   }
421 }
422 
423 void ThreadPlanCallFunction::ClearBreakpoints() {
424   if (m_trap_exceptions) {
425     if (m_cxx_language_runtime && m_should_clear_cxx_exception_bp)
426       m_cxx_language_runtime->ClearExceptionBreakpoints();
427     if (m_objc_language_runtime && m_should_clear_objc_exception_bp)
428       m_objc_language_runtime->ClearExceptionBreakpoints();
429   }
430 }
431 
432 bool ThreadPlanCallFunction::BreakpointsExplainStop() {
433   StopInfoSP stop_info_sp = GetPrivateStopInfo();
434 
435   if (m_trap_exceptions) {
436     if ((m_cxx_language_runtime &&
437          m_cxx_language_runtime->ExceptionBreakpointsExplainStop(
438              stop_info_sp)) ||
439         (m_objc_language_runtime &&
440          m_objc_language_runtime->ExceptionBreakpointsExplainStop(
441              stop_info_sp))) {
442       Log *log = GetLog(LLDBLog::Step);
443       LLDB_LOGF(log, "ThreadPlanCallFunction::BreakpointsExplainStop - Hit an "
444                      "exception breakpoint, setting plan complete.");
445 
446       SetPlanComplete(false);
447 
448       // If the user has set the ObjC language breakpoint, it would normally
449       // get priority over our internal catcher breakpoint, but in this case we
450       // can't let that happen, so force the ShouldStop here.
451       stop_info_sp->OverrideShouldStop(true);
452       return true;
453     }
454   }
455 
456   return false;
457 }
458 
459 void ThreadPlanCallFunction::SetStopOthers(bool new_value) {
460   m_subplan_sp->SetStopOthers(new_value);
461 }
462 
463 void ThreadPlanCallFunction::RestoreThreadState() {
464   GetThread().RestoreThreadStateFromCheckpoint(m_stored_thread_state);
465 }
466 
467 void ThreadPlanCallFunction::SetReturnValue() {
468   const ABI *abi = m_process.GetABI().get();
469   if (abi && m_return_type.IsValid()) {
470     const bool persistent = false;
471     m_return_valobj_sp =
472         abi->GetReturnValueObject(GetThread(), m_return_type, persistent);
473   }
474 }
475