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_private::ConstString
GetPluginNameStatic()58 InstrumentationRuntimeMainThreadChecker::GetPluginNameStatic() {
59 return ConstString("MainThreadChecker");
60 }
61
62 lldb::InstrumentationRuntimeType
GetTypeStatic()63 InstrumentationRuntimeMainThreadChecker::GetTypeStatic() {
64 return eInstrumentationRuntimeTypeMainThreadChecker;
65 }
66
67 const RegularExpression &
GetPatternForRuntimeLibrary()68 InstrumentationRuntimeMainThreadChecker::GetPatternForRuntimeLibrary() {
69 static RegularExpression regex(llvm::StringRef("libMainThreadChecker.dylib"));
70 return regex;
71 }
72
CheckIfRuntimeIsValid(const lldb::ModuleSP module_sp)73 bool InstrumentationRuntimeMainThreadChecker::CheckIfRuntimeIsValid(
74 const lldb::ModuleSP module_sp) {
75 static ConstString test_sym("__main_thread_checker_on_report");
76 const Symbol *symbol =
77 module_sp->FindFirstSymbolWithNameAndType(test_sym, lldb::eSymbolTypeAny);
78 return symbol != nullptr;
79 }
80
81 StructuredData::ObjectSP
RetrieveReportData(ExecutionContextRef exe_ctx_ref)82 InstrumentationRuntimeMainThreadChecker::RetrieveReportData(
83 ExecutionContextRef exe_ctx_ref) {
84 ProcessSP process_sp = GetProcessSP();
85 if (!process_sp)
86 return StructuredData::ObjectSP();
87
88 ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();
89 StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
90 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
91 Target &target = process_sp->GetTarget();
92
93 if (!frame_sp)
94 return StructuredData::ObjectSP();
95
96 RegisterContextSP regctx_sp = frame_sp->GetRegisterContext();
97 if (!regctx_sp)
98 return StructuredData::ObjectSP();
99
100 const RegisterInfo *reginfo = regctx_sp->GetRegisterInfoByName("arg1");
101 if (!reginfo)
102 return StructuredData::ObjectSP();
103
104 uint64_t apiname_ptr = regctx_sp->ReadRegisterAsUnsigned(reginfo, 0);
105 if (!apiname_ptr)
106 return StructuredData::ObjectSP();
107
108 std::string apiName = "";
109 Status read_error;
110 target.ReadCStringFromMemory(apiname_ptr, apiName, read_error);
111 if (read_error.Fail())
112 return StructuredData::ObjectSP();
113
114 std::string className = "";
115 std::string selector = "";
116 if (apiName.substr(0, 2) == "-[") {
117 size_t spacePos = apiName.find(' ');
118 if (spacePos != std::string::npos) {
119 className = apiName.substr(2, spacePos - 2);
120 selector = apiName.substr(spacePos + 1, apiName.length() - spacePos - 2);
121 }
122 }
123
124 // Gather the PCs of the user frames in the backtrace.
125 StructuredData::Array *trace = new StructuredData::Array();
126 auto trace_sp = StructuredData::ObjectSP(trace);
127 StackFrameSP responsible_frame;
128 for (unsigned I = 0; I < thread_sp->GetStackFrameCount(); ++I) {
129 StackFrameSP frame = thread_sp->GetStackFrameAtIndex(I);
130 Address addr = frame->GetFrameCodeAddressForSymbolication();
131 if (addr.GetModule() == runtime_module_sp) // Skip PCs from the runtime.
132 continue;
133
134 // The first non-runtime frame is responsible for the bug.
135 if (!responsible_frame)
136 responsible_frame = frame;
137
138 lldb::addr_t PC = addr.GetLoadAddress(&target);
139 trace->AddItem(StructuredData::ObjectSP(new StructuredData::Integer(PC)));
140 }
141
142 auto *d = new StructuredData::Dictionary();
143 auto dict_sp = StructuredData::ObjectSP(d);
144 d->AddStringItem("instrumentation_class", "MainThreadChecker");
145 d->AddStringItem("api_name", apiName);
146 d->AddStringItem("class_name", className);
147 d->AddStringItem("selector", selector);
148 d->AddStringItem("description",
149 apiName + " must be used from main thread only");
150 d->AddIntegerItem("tid", thread_sp->GetIndexID());
151 d->AddItem("trace", trace_sp);
152 return dict_sp;
153 }
154
NotifyBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)155 bool InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit(
156 void *baton, StoppointCallbackContext *context, user_id_t break_id,
157 user_id_t break_loc_id) {
158 assert(baton && "null baton");
159 if (!baton)
160 return false; ///< false => resume execution.
161
162 InstrumentationRuntimeMainThreadChecker *const instance =
163 static_cast<InstrumentationRuntimeMainThreadChecker *>(baton);
164
165 ProcessSP process_sp = instance->GetProcessSP();
166 ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();
167 if (!process_sp || !thread_sp ||
168 process_sp != context->exe_ctx_ref.GetProcessSP())
169 return false;
170
171 if (process_sp->GetModIDRef().IsLastResumeForUserExpression())
172 return false;
173
174 StructuredData::ObjectSP report =
175 instance->RetrieveReportData(context->exe_ctx_ref);
176
177 if (report) {
178 std::string description = std::string(report->GetAsDictionary()
179 ->GetValueForKey("description")
180 ->GetAsString()
181 ->GetValue());
182 thread_sp->SetStopInfo(
183 InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(
184 *thread_sp, description, report));
185 return true;
186 }
187
188 return false;
189 }
190
Activate()191 void InstrumentationRuntimeMainThreadChecker::Activate() {
192 if (IsActive())
193 return;
194
195 ProcessSP process_sp = GetProcessSP();
196 if (!process_sp)
197 return;
198
199 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
200
201 ConstString symbol_name("__main_thread_checker_on_report");
202 const Symbol *symbol = runtime_module_sp->FindFirstSymbolWithNameAndType(
203 symbol_name, eSymbolTypeCode);
204
205 if (symbol == nullptr)
206 return;
207
208 if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())
209 return;
210
211 Target &target = process_sp->GetTarget();
212 addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(&target);
213
214 if (symbol_address == LLDB_INVALID_ADDRESS)
215 return;
216
217 Breakpoint *breakpoint =
218 process_sp->GetTarget()
219 .CreateBreakpoint(symbol_address, /*internal=*/true,
220 /*hardware=*/false)
221 .get();
222 breakpoint->SetCallback(
223 InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit, this, true);
224 breakpoint->SetBreakpointKind("main-thread-checker-report");
225 SetBreakpointID(breakpoint->GetID());
226
227 SetActive(true);
228 }
229
Deactivate()230 void InstrumentationRuntimeMainThreadChecker::Deactivate() {
231 SetActive(false);
232
233 auto BID = GetBreakpointID();
234 if (BID == LLDB_INVALID_BREAK_ID)
235 return;
236
237 if (ProcessSP process_sp = GetProcessSP()) {
238 process_sp->GetTarget().RemoveBreakpointByID(BID);
239 SetBreakpointID(LLDB_INVALID_BREAK_ID);
240 }
241 }
242
243 lldb::ThreadCollectionSP
GetBacktracesFromExtendedStopInfo(StructuredData::ObjectSP info)244 InstrumentationRuntimeMainThreadChecker::GetBacktracesFromExtendedStopInfo(
245 StructuredData::ObjectSP info) {
246 ThreadCollectionSP threads;
247 threads = std::make_shared<ThreadCollection>();
248
249 ProcessSP process_sp = GetProcessSP();
250
251 if (info->GetObjectForDotSeparatedPath("instrumentation_class")
252 ->GetStringValue() != "MainThreadChecker")
253 return threads;
254
255 std::vector<lldb::addr_t> PCs;
256 auto trace = info->GetObjectForDotSeparatedPath("trace")->GetAsArray();
257 trace->ForEach([&PCs](StructuredData::Object *PC) -> bool {
258 PCs.push_back(PC->GetAsInteger()->GetValue());
259 return true;
260 });
261
262 if (PCs.empty())
263 return threads;
264
265 StructuredData::ObjectSP thread_id_obj =
266 info->GetObjectForDotSeparatedPath("tid");
267 tid_t tid = thread_id_obj ? thread_id_obj->GetIntegerValue() : 0;
268
269 // We gather symbolication addresses above, so no need for HistoryThread to
270 // try to infer the call addresses.
271 bool pcs_are_call_addresses = true;
272 ThreadSP new_thread_sp = std::make_shared<HistoryThread>(
273 *process_sp, tid, PCs, pcs_are_call_addresses);
274
275 // Save this in the Process' ExtendedThreadList so a strong pointer retains
276 // the object
277 process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
278 threads->AddThread(new_thread_sp);
279
280 return threads;
281 }
282