1 //===-- InstrumentationRuntimeMainThreadChecker.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 "InstrumentationRuntimeMainThreadChecker.h"
10
11 #include "Plugins/Process/Utility/HistoryThread.h"
12 #include "lldb/Breakpoint/StoppointCallbackContext.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Symbol/Symbol.h"
16 #include "lldb/Symbol/SymbolContext.h"
17 #include "lldb/Symbol/Variable.h"
18 #include "lldb/Symbol/VariableList.h"
19 #include "lldb/Target/InstrumentationRuntimeStopInfo.h"
20 #include "lldb/Target/RegisterContext.h"
21 #include "lldb/Target/SectionLoadList.h"
22 #include "lldb/Target/StopInfo.h"
23 #include "lldb/Target/Target.h"
24 #include "lldb/Target/Thread.h"
25 #include "lldb/Utility/RegularExpression.h"
26
27 #include <memory>
28
29 using namespace lldb;
30 using namespace lldb_private;
31
LLDB_PLUGIN_DEFINE(InstrumentationRuntimeMainThreadChecker)32 LLDB_PLUGIN_DEFINE(InstrumentationRuntimeMainThreadChecker)
33
34 InstrumentationRuntimeMainThreadChecker::
35 ~InstrumentationRuntimeMainThreadChecker() {
36 Deactivate();
37 }
38
39 lldb::InstrumentationRuntimeSP
CreateInstance(const lldb::ProcessSP & process_sp)40 InstrumentationRuntimeMainThreadChecker::CreateInstance(
41 const lldb::ProcessSP &process_sp) {
42 return InstrumentationRuntimeSP(
43 new InstrumentationRuntimeMainThreadChecker(process_sp));
44 }
45
Initialize()46 void InstrumentationRuntimeMainThreadChecker::Initialize() {
47 PluginManager::RegisterPlugin(
48 GetPluginNameStatic(),
49 "MainThreadChecker instrumentation runtime plugin.", CreateInstance,
50 GetTypeStatic);
51 }
52
Terminate()53 void InstrumentationRuntimeMainThreadChecker::Terminate() {
54 PluginManager::UnregisterPlugin(CreateInstance);
55 }
56
57 lldb::InstrumentationRuntimeType
GetTypeStatic()58 InstrumentationRuntimeMainThreadChecker::GetTypeStatic() {
59 return eInstrumentationRuntimeTypeMainThreadChecker;
60 }
61
62 const RegularExpression &
GetPatternForRuntimeLibrary()63 InstrumentationRuntimeMainThreadChecker::GetPatternForRuntimeLibrary() {
64 static RegularExpression regex(llvm::StringRef("libMainThreadChecker.dylib"));
65 return regex;
66 }
67
CheckIfRuntimeIsValid(const lldb::ModuleSP module_sp)68 bool InstrumentationRuntimeMainThreadChecker::CheckIfRuntimeIsValid(
69 const lldb::ModuleSP module_sp) {
70 static ConstString test_sym("__main_thread_checker_on_report");
71 const Symbol *symbol =
72 module_sp->FindFirstSymbolWithNameAndType(test_sym, lldb::eSymbolTypeAny);
73 return symbol != nullptr;
74 }
75
76 StructuredData::ObjectSP
RetrieveReportData(ExecutionContextRef exe_ctx_ref)77 InstrumentationRuntimeMainThreadChecker::RetrieveReportData(
78 ExecutionContextRef exe_ctx_ref) {
79 ProcessSP process_sp = GetProcessSP();
80 if (!process_sp)
81 return StructuredData::ObjectSP();
82
83 ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();
84 StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
85 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
86 Target &target = process_sp->GetTarget();
87
88 if (!frame_sp)
89 return StructuredData::ObjectSP();
90
91 RegisterContextSP regctx_sp = frame_sp->GetRegisterContext();
92 if (!regctx_sp)
93 return StructuredData::ObjectSP();
94
95 const RegisterInfo *reginfo = regctx_sp->GetRegisterInfoByName("arg1");
96 if (!reginfo)
97 return StructuredData::ObjectSP();
98
99 uint64_t apiname_ptr = regctx_sp->ReadRegisterAsUnsigned(reginfo, 0);
100 if (!apiname_ptr)
101 return StructuredData::ObjectSP();
102
103 std::string apiName;
104 Status read_error;
105 target.ReadCStringFromMemory(apiname_ptr, apiName, read_error);
106 if (read_error.Fail())
107 return StructuredData::ObjectSP();
108
109 std::string className;
110 std::string selector;
111 if (apiName.substr(0, 2) == "-[") {
112 size_t spacePos = apiName.find(' ');
113 if (spacePos != std::string::npos) {
114 className = apiName.substr(2, spacePos - 2);
115 selector = apiName.substr(spacePos + 1, apiName.length() - spacePos - 2);
116 }
117 }
118
119 // Gather the PCs of the user frames in the backtrace.
120 StructuredData::Array *trace = new StructuredData::Array();
121 auto trace_sp = StructuredData::ObjectSP(trace);
122 StackFrameSP responsible_frame;
123 for (unsigned I = 0; I < thread_sp->GetStackFrameCount(); ++I) {
124 StackFrameSP frame = thread_sp->GetStackFrameAtIndex(I);
125 Address addr = frame->GetFrameCodeAddressForSymbolication();
126 if (addr.GetModule() == runtime_module_sp) // Skip PCs from the runtime.
127 continue;
128
129 // The first non-runtime frame is responsible for the bug.
130 if (!responsible_frame)
131 responsible_frame = frame;
132
133 lldb::addr_t PC = addr.GetLoadAddress(&target);
134 trace->AddItem(StructuredData::ObjectSP(new StructuredData::Integer(PC)));
135 }
136
137 auto *d = new StructuredData::Dictionary();
138 auto dict_sp = StructuredData::ObjectSP(d);
139 d->AddStringItem("instrumentation_class", "MainThreadChecker");
140 d->AddStringItem("api_name", apiName);
141 d->AddStringItem("class_name", className);
142 d->AddStringItem("selector", selector);
143 d->AddStringItem("description",
144 apiName + " must be used from main thread only");
145 d->AddIntegerItem("tid", thread_sp->GetIndexID());
146 d->AddItem("trace", trace_sp);
147 return dict_sp;
148 }
149
NotifyBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)150 bool InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit(
151 void *baton, StoppointCallbackContext *context, user_id_t break_id,
152 user_id_t break_loc_id) {
153 assert(baton && "null baton");
154 if (!baton)
155 return false; ///< false => resume execution.
156
157 InstrumentationRuntimeMainThreadChecker *const instance =
158 static_cast<InstrumentationRuntimeMainThreadChecker *>(baton);
159
160 ProcessSP process_sp = instance->GetProcessSP();
161 ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();
162 if (!process_sp || !thread_sp ||
163 process_sp != context->exe_ctx_ref.GetProcessSP())
164 return false;
165
166 if (process_sp->GetModIDRef().IsLastResumeForUserExpression())
167 return false;
168
169 StructuredData::ObjectSP report =
170 instance->RetrieveReportData(context->exe_ctx_ref);
171
172 if (report) {
173 std::string description = std::string(report->GetAsDictionary()
174 ->GetValueForKey("description")
175 ->GetAsString()
176 ->GetValue());
177 thread_sp->SetStopInfo(
178 InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(
179 *thread_sp, description, report));
180 return true;
181 }
182
183 return false;
184 }
185
Activate()186 void InstrumentationRuntimeMainThreadChecker::Activate() {
187 if (IsActive())
188 return;
189
190 ProcessSP process_sp = GetProcessSP();
191 if (!process_sp)
192 return;
193
194 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
195
196 ConstString symbol_name("__main_thread_checker_on_report");
197 const Symbol *symbol = runtime_module_sp->FindFirstSymbolWithNameAndType(
198 symbol_name, eSymbolTypeCode);
199
200 if (symbol == nullptr)
201 return;
202
203 if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())
204 return;
205
206 Target &target = process_sp->GetTarget();
207 addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(&target);
208
209 if (symbol_address == LLDB_INVALID_ADDRESS)
210 return;
211
212 Breakpoint *breakpoint =
213 process_sp->GetTarget()
214 .CreateBreakpoint(symbol_address, /*internal=*/true,
215 /*hardware=*/false)
216 .get();
217 const bool sync = false;
218 breakpoint->SetCallback(
219 InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit, this, sync);
220 breakpoint->SetBreakpointKind("main-thread-checker-report");
221 SetBreakpointID(breakpoint->GetID());
222
223 SetActive(true);
224 }
225
Deactivate()226 void InstrumentationRuntimeMainThreadChecker::Deactivate() {
227 SetActive(false);
228
229 auto BID = GetBreakpointID();
230 if (BID == LLDB_INVALID_BREAK_ID)
231 return;
232
233 if (ProcessSP process_sp = GetProcessSP()) {
234 process_sp->GetTarget().RemoveBreakpointByID(BID);
235 SetBreakpointID(LLDB_INVALID_BREAK_ID);
236 }
237 }
238
239 lldb::ThreadCollectionSP
GetBacktracesFromExtendedStopInfo(StructuredData::ObjectSP info)240 InstrumentationRuntimeMainThreadChecker::GetBacktracesFromExtendedStopInfo(
241 StructuredData::ObjectSP info) {
242 ThreadCollectionSP threads;
243 threads = std::make_shared<ThreadCollection>();
244
245 ProcessSP process_sp = GetProcessSP();
246
247 if (info->GetObjectForDotSeparatedPath("instrumentation_class")
248 ->GetStringValue() != "MainThreadChecker")
249 return threads;
250
251 std::vector<lldb::addr_t> PCs;
252 auto trace = info->GetObjectForDotSeparatedPath("trace")->GetAsArray();
253 trace->ForEach([&PCs](StructuredData::Object *PC) -> bool {
254 PCs.push_back(PC->GetAsInteger()->GetValue());
255 return true;
256 });
257
258 if (PCs.empty())
259 return threads;
260
261 StructuredData::ObjectSP thread_id_obj =
262 info->GetObjectForDotSeparatedPath("tid");
263 tid_t tid = thread_id_obj ? thread_id_obj->GetIntegerValue() : 0;
264
265 // We gather symbolication addresses above, so no need for HistoryThread to
266 // try to infer the call addresses.
267 bool pcs_are_call_addresses = true;
268 ThreadSP new_thread_sp = std::make_shared<HistoryThread>(
269 *process_sp, tid, PCs, pcs_are_call_addresses);
270
271 // Save this in the Process' ExtendedThreadList so a strong pointer retains
272 // the object
273 process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
274 threads->AddThread(new_thread_sp);
275
276 return threads;
277 }
278