1 //===-- MemoryHistoryASan.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 "MemoryHistoryASan.h" 10 11 #include "lldb/Target/MemoryHistory.h" 12 13 #include "Plugins/Process/Utility/HistoryThread.h" 14 #include "lldb/Core/Debugger.h" 15 #include "lldb/Core/Module.h" 16 #include "lldb/Core/PluginInterface.h" 17 #include "lldb/Core/PluginManager.h" 18 #include "lldb/Core/ValueObject.h" 19 #include "lldb/Expression/UserExpression.h" 20 #include "lldb/Target/ExecutionContext.h" 21 #include "lldb/Target/Target.h" 22 #include "lldb/Target/Thread.h" 23 #include "lldb/Target/ThreadList.h" 24 #include "lldb/lldb-private.h" 25 26 #include <sstream> 27 28 using namespace lldb; 29 using namespace lldb_private; 30 31 LLDB_PLUGIN_DEFINE(MemoryHistoryASan) 32 33 MemoryHistorySP MemoryHistoryASan::CreateInstance(const ProcessSP &process_sp) { 34 if (!process_sp.get()) 35 return nullptr; 36 37 Target &target = process_sp->GetTarget(); 38 39 for (ModuleSP module_sp : target.GetImages().Modules()) { 40 const Symbol *symbol = module_sp->FindFirstSymbolWithNameAndType( 41 ConstString("__asan_get_alloc_stack"), lldb::eSymbolTypeAny); 42 43 if (symbol != nullptr) 44 return MemoryHistorySP(new MemoryHistoryASan(process_sp)); 45 } 46 47 return MemoryHistorySP(); 48 } 49 50 void MemoryHistoryASan::Initialize() { 51 PluginManager::RegisterPlugin( 52 GetPluginNameStatic(), "ASan memory history provider.", CreateInstance); 53 } 54 55 void MemoryHistoryASan::Terminate() { 56 PluginManager::UnregisterPlugin(CreateInstance); 57 } 58 59 MemoryHistoryASan::MemoryHistoryASan(const ProcessSP &process_sp) { 60 if (process_sp) 61 m_process_wp = process_sp; 62 } 63 64 const char *memory_history_asan_command_prefix = R"( 65 extern "C" 66 { 67 size_t __asan_get_alloc_stack(void *addr, void **trace, size_t size, int *thread_id); 68 size_t __asan_get_free_stack(void *addr, void **trace, size_t size, int *thread_id); 69 } 70 71 struct data { 72 void *alloc_trace[256]; 73 size_t alloc_count; 74 int alloc_tid; 75 76 void *free_trace[256]; 77 size_t free_count; 78 int free_tid; 79 }; 80 )"; 81 82 const char *memory_history_asan_command_format = 83 R"( 84 data t; 85 86 t.alloc_count = __asan_get_alloc_stack((void *)0x%)" PRIx64 87 R"(, t.alloc_trace, 256, &t.alloc_tid); 88 t.free_count = __asan_get_free_stack((void *)0x%)" PRIx64 89 R"(, t.free_trace, 256, &t.free_tid); 90 91 t; 92 )"; 93 94 static void CreateHistoryThreadFromValueObject(ProcessSP process_sp, 95 ValueObjectSP return_value_sp, 96 const char *type, 97 const char *thread_name, 98 HistoryThreads &result) { 99 std::string count_path = "." + std::string(type) + "_count"; 100 std::string tid_path = "." + std::string(type) + "_tid"; 101 std::string trace_path = "." + std::string(type) + "_trace"; 102 103 ValueObjectSP count_sp = 104 return_value_sp->GetValueForExpressionPath(count_path.c_str()); 105 ValueObjectSP tid_sp = 106 return_value_sp->GetValueForExpressionPath(tid_path.c_str()); 107 108 if (!count_sp || !tid_sp) 109 return; 110 111 int count = count_sp->GetValueAsUnsigned(0); 112 tid_t tid = tid_sp->GetValueAsUnsigned(0) + 1; 113 114 if (count <= 0) 115 return; 116 117 ValueObjectSP trace_sp = 118 return_value_sp->GetValueForExpressionPath(trace_path.c_str()); 119 120 if (!trace_sp) 121 return; 122 123 std::vector<lldb::addr_t> pcs; 124 for (int i = 0; i < count; i++) { 125 addr_t pc = trace_sp->GetChildAtIndex(i, true)->GetValueAsUnsigned(0); 126 if (pc == 0 || pc == 1 || pc == LLDB_INVALID_ADDRESS) 127 continue; 128 pcs.push_back(pc); 129 } 130 131 // The ASAN runtime already massages the return addresses into call 132 // addresses, we don't want LLDB's unwinder to try to locate the previous 133 // instruction again as this might lead to us reporting a different line. 134 bool pcs_are_call_addresses = true; 135 HistoryThread *history_thread = 136 new HistoryThread(*process_sp, tid, pcs, pcs_are_call_addresses); 137 ThreadSP new_thread_sp(history_thread); 138 std::ostringstream thread_name_with_number; 139 thread_name_with_number << thread_name << " Thread " << tid; 140 history_thread->SetThreadName(thread_name_with_number.str().c_str()); 141 // Save this in the Process' ExtendedThreadList so a strong pointer retains 142 // the object 143 process_sp->GetExtendedThreadList().AddThread(new_thread_sp); 144 result.push_back(new_thread_sp); 145 } 146 147 HistoryThreads MemoryHistoryASan::GetHistoryThreads(lldb::addr_t address) { 148 HistoryThreads result; 149 150 ProcessSP process_sp = m_process_wp.lock(); 151 if (!process_sp) 152 return result; 153 154 ThreadSP thread_sp = 155 process_sp->GetThreadList().GetExpressionExecutionThread(); 156 if (!thread_sp) 157 return result; 158 159 StackFrameSP frame_sp = thread_sp->GetSelectedFrame(); 160 if (!frame_sp) 161 return result; 162 163 ExecutionContext exe_ctx(frame_sp); 164 ValueObjectSP return_value_sp; 165 StreamString expr; 166 Status eval_error; 167 expr.Printf(memory_history_asan_command_format, address, address); 168 169 EvaluateExpressionOptions options; 170 options.SetUnwindOnError(true); 171 options.SetTryAllThreads(true); 172 options.SetStopOthers(true); 173 options.SetIgnoreBreakpoints(true); 174 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 175 options.SetPrefix(memory_history_asan_command_prefix); 176 options.SetAutoApplyFixIts(false); 177 options.SetLanguage(eLanguageTypeObjC_plus_plus); 178 179 ExpressionResults expr_result = UserExpression::Evaluate( 180 exe_ctx, options, expr.GetString(), "", return_value_sp, eval_error); 181 if (expr_result != eExpressionCompleted) { 182 StreamString ss; 183 ss << "cannot evaluate AddressSanitizer expression:\n"; 184 ss << eval_error.AsCString(); 185 Debugger::ReportWarning(ss.GetString().str(), 186 process_sp->GetTarget().GetDebugger().GetID()); 187 return result; 188 } 189 190 if (!return_value_sp) 191 return result; 192 193 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "free", 194 "Memory deallocated by", result); 195 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "alloc", 196 "Memory allocated by", result); 197 198 return result; 199 } 200