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 72 const char *memory_history_asan_command_format = 73 R"( 74 struct { 75 void *alloc_trace[256]; 76 size_t alloc_count; 77 int alloc_tid; 78 79 void *free_trace[256]; 80 size_t free_count; 81 int free_tid; 82 } t; 83 84 t.alloc_count = __asan_get_alloc_stack((void *)0x%)" PRIx64 85 R"(, t.alloc_trace, 256, &t.alloc_tid); 86 t.free_count = __asan_get_free_stack((void *)0x%)" PRIx64 87 R"(, t.free_trace, 256, &t.free_tid); 88 89 t; 90 )"; 91 92 static void CreateHistoryThreadFromValueObject(ProcessSP process_sp, 93 ValueObjectSP return_value_sp, 94 const char *type, 95 const char *thread_name, 96 HistoryThreads &result) { 97 std::string count_path = "." + std::string(type) + "_count"; 98 std::string tid_path = "." + std::string(type) + "_tid"; 99 std::string trace_path = "." + std::string(type) + "_trace"; 100 101 ValueObjectSP count_sp = 102 return_value_sp->GetValueForExpressionPath(count_path.c_str()); 103 ValueObjectSP tid_sp = 104 return_value_sp->GetValueForExpressionPath(tid_path.c_str()); 105 106 if (!count_sp || !tid_sp) 107 return; 108 109 int count = count_sp->GetValueAsUnsigned(0); 110 tid_t tid = tid_sp->GetValueAsUnsigned(0) + 1; 111 112 if (count <= 0) 113 return; 114 115 ValueObjectSP trace_sp = 116 return_value_sp->GetValueForExpressionPath(trace_path.c_str()); 117 118 if (!trace_sp) 119 return; 120 121 std::vector<lldb::addr_t> pcs; 122 for (int i = 0; i < count; i++) { 123 addr_t pc = trace_sp->GetChildAtIndex(i)->GetValueAsUnsigned(0); 124 if (pc == 0 || pc == 1 || pc == LLDB_INVALID_ADDRESS) 125 continue; 126 pcs.push_back(pc); 127 } 128 129 // The ASAN runtime already massages the return addresses into call 130 // addresses, we don't want LLDB's unwinder to try to locate the previous 131 // instruction again as this might lead to us reporting a different line. 132 bool pcs_are_call_addresses = true; 133 HistoryThread *history_thread = 134 new HistoryThread(*process_sp, tid, pcs, pcs_are_call_addresses); 135 ThreadSP new_thread_sp(history_thread); 136 std::ostringstream thread_name_with_number; 137 thread_name_with_number << thread_name << " Thread " << tid; 138 history_thread->SetThreadName(thread_name_with_number.str().c_str()); 139 // Save this in the Process' ExtendedThreadList so a strong pointer retains 140 // the object 141 process_sp->GetExtendedThreadList().AddThread(new_thread_sp); 142 result.push_back(new_thread_sp); 143 } 144 145 HistoryThreads MemoryHistoryASan::GetHistoryThreads(lldb::addr_t address) { 146 HistoryThreads result; 147 148 ProcessSP process_sp = m_process_wp.lock(); 149 if (!process_sp) 150 return result; 151 152 ThreadSP thread_sp = 153 process_sp->GetThreadList().GetExpressionExecutionThread(); 154 if (!thread_sp) 155 return result; 156 157 StackFrameSP frame_sp = 158 thread_sp->GetSelectedFrame(DoNoSelectMostRelevantFrame); 159 if (!frame_sp) 160 return result; 161 162 ExecutionContext exe_ctx(frame_sp); 163 ValueObjectSP return_value_sp; 164 StreamString expr; 165 Status eval_error; 166 expr.Printf(memory_history_asan_command_format, address, address); 167 168 EvaluateExpressionOptions options; 169 options.SetUnwindOnError(true); 170 options.SetTryAllThreads(true); 171 options.SetStopOthers(true); 172 options.SetIgnoreBreakpoints(true); 173 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 174 options.SetPrefix(memory_history_asan_command_prefix); 175 options.SetAutoApplyFixIts(false); 176 options.SetLanguage(eLanguageTypeObjC_plus_plus); 177 178 ExpressionResults expr_result = UserExpression::Evaluate( 179 exe_ctx, options, expr.GetString(), "", return_value_sp, eval_error); 180 if (expr_result != eExpressionCompleted) { 181 StreamString ss; 182 ss << "cannot evaluate AddressSanitizer expression:\n"; 183 ss << eval_error.AsCString(); 184 Debugger::ReportWarning(ss.GetString().str(), 185 process_sp->GetTarget().GetDebugger().GetID()); 186 return result; 187 } 188 189 if (!return_value_sp) 190 return result; 191 192 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "free", 193 "Memory deallocated by", result); 194 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "alloc", 195 "Memory allocated by", result); 196 197 return result; 198 } 199