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
30using namespace lldb;
31using namespace lldb_private;
32
33// ThreadPlanCallFunction: Plan to call a single function
34bool 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(mask: 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(load_addr: m_function_sp, byte_size: 4, fail_value: 0, error);
59 if (!error.Success()) {
60 m_constructor_errors.Printf(
61 format: "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 format: "%s", llvm::toString(E: 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(target: &GetTarget());
79
80 // Checkpoint the thread state so we can restore it later.
81 if (log && log->GetVerbose())
82 ReportRegisterState(message: "About to checkpoint thread before function call. "
83 "Original register state was:");
84
85 if (!thread.CheckpointThreadState(saved_state&: m_stored_thread_state)) {
86 m_constructor_errors.Printf(format: "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(target: &GetTarget());
93
94 return true;
95}
96
97ThreadPlanCallFunction::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, sp: m_function_sp, functionAddress: function_load_addr,
122 returnAddress: start_load_addr, args))
123 return;
124
125 ReportRegisterState(message: "Function call was set up. Register state was:");
126
127 m_valid = true;
128}
129
130ThreadPlanCallFunction::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
148ThreadPlanCallFunction::~ThreadPlanCallFunction() {
149 DoTakedown(success: PlanSucceeded());
150}
151
152void ThreadPlanCallFunction::ReportRegisterState(const char *message) {
153 Log *log = GetLog(mask: LLDBLog::Step);
154 if (log && log->GetVerbose()) {
155 StreamString strm;
156 RegisterContext *reg_ctx = GetThread().GetRegisterContext().get();
157
158 log->PutCString(cstr: 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: reg_idx);
165 if (reg_ctx->ReadRegister(reg_info, reg_value)) {
166 DumpRegisterValue(reg_val: reg_value, s&: strm, reg_info: *reg_info, prefix_with_name: true, prefix_with_alt_name: false,
167 format: eFormatDefault);
168 strm.EOL();
169 }
170 }
171 log->PutString(str: strm.GetString());
172 }
173}
174
175void ThreadPlanCallFunction::DoTakedown(bool success) {
176 Log *log = GetLog(mask: LLDBLog::Step);
177 Thread &thread = GetThread();
178
179 if (!m_valid) {
180 // If ConstructorSetup was succesfull but PrepareTrivialCall was not,
181 // we will have a saved register state and potentially modified registers.
182 // Restore those.
183 if (m_stored_thread_state.register_backup_sp)
184 if (!thread.RestoreRegisterStateFromCheckpoint(saved_state&: m_stored_thread_state))
185 LLDB_LOGF(
186 log,
187 "ThreadPlanCallFunction(%p): Failed to restore register state from "
188 "invalid plan that contained a saved register state.",
189 static_cast<void *>(this));
190
191 // Don't call DoTakedown if we were never valid to begin with.
192 LLDB_LOGF(log,
193 "ThreadPlanCallFunction(%p): Log called on "
194 "ThreadPlanCallFunction that was never valid.",
195 static_cast<void *>(this));
196 return;
197 }
198
199 if (!m_takedown_done) {
200 if (success) {
201 SetReturnValue();
202 }
203 LLDB_LOGF(log,
204 "ThreadPlanCallFunction(%p): DoTakedown called for thread "
205 "0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
206 static_cast<void *>(this), m_tid, m_valid, IsPlanComplete());
207 m_takedown_done = true;
208 m_stop_address =
209 thread.GetStackFrameAtIndex(idx: 0)->GetRegisterContext()->GetPC();
210 m_real_stop_info_sp = GetPrivateStopInfo();
211 if (!thread.RestoreRegisterStateFromCheckpoint(saved_state&: m_stored_thread_state)) {
212 LLDB_LOGF(log,
213 "ThreadPlanCallFunction(%p): DoTakedown failed to restore "
214 "register state",
215 static_cast<void *>(this));
216 }
217 SetPlanComplete(success);
218 ClearBreakpoints();
219 if (log && log->GetVerbose())
220 ReportRegisterState(message: "Restoring thread state after function call. "
221 "Restored register state:");
222 } else {
223 LLDB_LOGF(log,
224 "ThreadPlanCallFunction(%p): DoTakedown called as no-op for "
225 "thread 0x%4.4" PRIx64 ", m_valid: %d complete: %d.\n",
226 static_cast<void *>(this), m_tid, m_valid, IsPlanComplete());
227 }
228}
229
230void ThreadPlanCallFunction::DidPop() { DoTakedown(success: PlanSucceeded()); }
231
232void ThreadPlanCallFunction::GetDescription(Stream *s, DescriptionLevel level) {
233 if (level == eDescriptionLevelBrief) {
234 s->Printf(format: "Function call thread plan");
235 } else {
236 s->Printf(format: "Thread plan to call 0x%" PRIx64,
237 m_function_addr.GetLoadAddress(target: &GetTarget()));
238 }
239}
240
241bool ThreadPlanCallFunction::ValidatePlan(Stream *error) {
242 if (!m_valid) {
243 if (error) {
244 if (m_constructor_errors.GetSize() > 0)
245 error->PutCString(cstr: m_constructor_errors.GetString());
246 else
247 error->PutCString(cstr: "Unknown error");
248 }
249 return false;
250 }
251
252 return true;
253}
254
255Vote ThreadPlanCallFunction::ShouldReportStop(Event *event_ptr) {
256 if (m_takedown_done || IsPlanComplete())
257 return eVoteYes;
258 else
259 return ThreadPlan::ShouldReportStop(event_ptr);
260}
261
262bool ThreadPlanCallFunction::DoPlanExplainsStop(Event *event_ptr) {
263 Log *log(GetLog(mask: LLDBLog::Step | LLDBLog::Process));
264 m_real_stop_info_sp = GetPrivateStopInfo();
265
266 // If our subplan knows why we stopped, even if it's done (which would
267 // forward the question to us) we answer yes.
268 if (m_subplan_sp && m_subplan_sp->PlanExplainsStop(event_ptr)) {
269 SetPlanComplete();
270 return true;
271 }
272
273 // Check if the breakpoint is one of ours.
274
275 StopReason stop_reason;
276 if (!m_real_stop_info_sp)
277 stop_reason = eStopReasonNone;
278 else
279 stop_reason = m_real_stop_info_sp->GetStopReason();
280 LLDB_LOG(log,
281 "ThreadPlanCallFunction::PlanExplainsStop: Got stop reason - {0}.",
282 Thread::StopReasonAsString(stop_reason));
283
284 if (stop_reason == eStopReasonBreakpoint && BreakpointsExplainStop())
285 return true;
286
287 // One more quirk here. If this event was from Halt interrupting the target,
288 // then we should not consider ourselves complete. Return true to
289 // acknowledge the stop.
290 if (Process::ProcessEventData::GetInterruptedFromEvent(event_ptr)) {
291 LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: The event is an "
292 "Interrupt, returning true.");
293 return true;
294 }
295 // We control breakpoints separately from other "stop reasons." So first,
296 // check the case where we stopped for an internal breakpoint, in that case,
297 // continue on. If it is not an internal breakpoint, consult
298 // m_ignore_breakpoints.
299
300 if (stop_reason == eStopReasonBreakpoint) {
301 uint64_t break_site_id = m_real_stop_info_sp->GetValue();
302 BreakpointSiteSP bp_site_sp;
303 bp_site_sp = m_process.GetBreakpointSiteList().FindByID(site_id: break_site_id);
304 if (bp_site_sp) {
305 uint32_t num_owners = bp_site_sp->GetNumberOfConstituents();
306 bool is_internal = true;
307 for (uint32_t i = 0; i < num_owners; i++) {
308 Breakpoint &bp = bp_site_sp->GetConstituentAtIndex(idx: i)->GetBreakpoint();
309 LLDB_LOGF(log,
310 "ThreadPlanCallFunction::PlanExplainsStop: hit "
311 "breakpoint %d while calling function",
312 bp.GetID());
313
314 if (!bp.IsInternal()) {
315 is_internal = false;
316 break;
317 }
318 }
319 if (is_internal) {
320 LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop hit an "
321 "internal breakpoint, not stopping.");
322 return false;
323 }
324 }
325
326 if (m_ignore_breakpoints) {
327 LLDB_LOGF(log,
328 "ThreadPlanCallFunction::PlanExplainsStop: we are ignoring "
329 "breakpoints, overriding breakpoint stop info ShouldStop, "
330 "returning true");
331 m_real_stop_info_sp->OverrideShouldStop(override_value: false);
332 return true;
333 } else {
334 LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop: we are not "
335 "ignoring breakpoints, overriding breakpoint stop info "
336 "ShouldStop, returning true");
337 m_real_stop_info_sp->OverrideShouldStop(override_value: true);
338 return false;
339 }
340 } else if (!m_unwind_on_error) {
341 // If we don't want to discard this plan, than any stop we don't understand
342 // should be propagated up the stack.
343 return false;
344 } else {
345 // If the subplan is running, any crashes are attributable to us. If we
346 // want to discard the plan, then we say we explain the stop but if we are
347 // going to be discarded, let whoever is above us explain the stop. But
348 // don't discard the plan if the stop would restart itself (for instance if
349 // it is a signal that is set not to stop. Check that here first. We just
350 // say we explain the stop but aren't done and everything will continue on
351 // from there.
352
353 if (m_real_stop_info_sp &&
354 m_real_stop_info_sp->ShouldStopSynchronous(event_ptr)) {
355 SetPlanComplete(false);
356 return m_subplan_sp ? m_unwind_on_error : false;
357 } else
358 return true;
359 }
360}
361
362bool ThreadPlanCallFunction::ShouldStop(Event *event_ptr) {
363 // We do some computation in DoPlanExplainsStop that may or may not set the
364 // plan as complete. We need to do that here to make sure our state is
365 // correct.
366 DoPlanExplainsStop(event_ptr);
367
368 if (IsPlanComplete()) {
369 ReportRegisterState(message: "Function completed. Register state was:");
370 return true;
371 } else {
372 return false;
373 }
374}
375
376bool ThreadPlanCallFunction::StopOthers() { return m_stop_other_threads; }
377
378StateType ThreadPlanCallFunction::GetPlanRunState() { return eStateRunning; }
379
380void ThreadPlanCallFunction::DidPush() {
381 //#define SINGLE_STEP_EXPRESSIONS
382
383 // Now set the thread state to "no reason" so we don't run with whatever
384 // signal was outstanding... Wait till the plan is pushed so we aren't
385 // changing the stop info till we're about to run.
386
387 GetThread().SetStopInfoToNothing();
388
389#ifndef SINGLE_STEP_EXPRESSIONS
390 Thread &thread = GetThread();
391 m_subplan_sp = std::make_shared<ThreadPlanRunToAddress>(args&: thread, args&: m_start_addr,
392 args&: m_stop_other_threads);
393
394 thread.QueueThreadPlan(plan_sp&: m_subplan_sp, abort_other_plans: false);
395 m_subplan_sp->SetPrivate(true);
396#endif
397}
398
399bool ThreadPlanCallFunction::WillStop() { return true; }
400
401bool ThreadPlanCallFunction::MischiefManaged() {
402 Log *log = GetLog(mask: LLDBLog::Step);
403
404 if (IsPlanComplete()) {
405 LLDB_LOGF(log, "ThreadPlanCallFunction(%p): Completed call function plan.",
406 static_cast<void *>(this));
407
408 ThreadPlan::MischiefManaged();
409 return true;
410 } else {
411 return false;
412 }
413}
414
415void ThreadPlanCallFunction::SetBreakpoints() {
416 if (m_trap_exceptions) {
417 m_cxx_language_runtime =
418 m_process.GetLanguageRuntime(language: eLanguageTypeC_plus_plus);
419 m_objc_language_runtime = m_process.GetLanguageRuntime(language: eLanguageTypeObjC);
420
421 if (m_cxx_language_runtime) {
422 m_should_clear_cxx_exception_bp =
423 !m_cxx_language_runtime->ExceptionBreakpointsAreSet();
424 m_cxx_language_runtime->SetExceptionBreakpoints();
425 }
426 if (m_objc_language_runtime) {
427 m_should_clear_objc_exception_bp =
428 !m_objc_language_runtime->ExceptionBreakpointsAreSet();
429 m_objc_language_runtime->SetExceptionBreakpoints();
430 }
431 }
432}
433
434void ThreadPlanCallFunction::ClearBreakpoints() {
435 if (m_trap_exceptions) {
436 if (m_cxx_language_runtime && m_should_clear_cxx_exception_bp)
437 m_cxx_language_runtime->ClearExceptionBreakpoints();
438 if (m_objc_language_runtime && m_should_clear_objc_exception_bp)
439 m_objc_language_runtime->ClearExceptionBreakpoints();
440 }
441}
442
443bool ThreadPlanCallFunction::BreakpointsExplainStop() {
444 StopInfoSP stop_info_sp = GetPrivateStopInfo();
445
446 if (m_trap_exceptions) {
447 if ((m_cxx_language_runtime &&
448 m_cxx_language_runtime->ExceptionBreakpointsExplainStop(
449 stop_reason: stop_info_sp)) ||
450 (m_objc_language_runtime &&
451 m_objc_language_runtime->ExceptionBreakpointsExplainStop(
452 stop_reason: stop_info_sp))) {
453 Log *log = GetLog(mask: LLDBLog::Step);
454 LLDB_LOGF(log, "ThreadPlanCallFunction::BreakpointsExplainStop - Hit an "
455 "exception breakpoint, setting plan complete.");
456
457 SetPlanComplete(false);
458
459 // If the user has set the ObjC language breakpoint, it would normally
460 // get priority over our internal catcher breakpoint, but in this case we
461 // can't let that happen, so force the ShouldStop here.
462 stop_info_sp->OverrideShouldStop(override_value: true);
463 return true;
464 }
465 }
466
467 return false;
468}
469
470void ThreadPlanCallFunction::SetStopOthers(bool new_value) {
471 m_subplan_sp->SetStopOthers(new_value);
472}
473
474void ThreadPlanCallFunction::RestoreThreadState() {
475 GetThread().RestoreThreadStateFromCheckpoint(saved_state&: m_stored_thread_state);
476}
477
478void ThreadPlanCallFunction::SetReturnValue() {
479 const ABI *abi = m_process.GetABI().get();
480 if (abi && m_return_type.IsValid()) {
481 const bool persistent = false;
482 m_return_valobj_sp =
483 abi->GetReturnValueObject(thread&: GetThread(), type&: m_return_type, persistent);
484 }
485}
486

source code of lldb/source/Target/ThreadPlanCallFunction.cpp