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/Symbol/SymbolContext.h"
12#include "lldb/Target/MemoryHistory.h"
13
14#include "Plugins/InstrumentationRuntime/Utility/Utility.h"
15#include "Plugins/Process/Utility/HistoryThread.h"
16#include "lldb/Core/Debugger.h"
17#include "lldb/Core/Module.h"
18#include "lldb/Core/PluginInterface.h"
19#include "lldb/Core/PluginManager.h"
20#include "lldb/Expression/UserExpression.h"
21#include "lldb/Target/ExecutionContext.h"
22#include "lldb/Target/Target.h"
23#include "lldb/Target/Thread.h"
24#include "lldb/Target/ThreadList.h"
25#include "lldb/ValueObject/ValueObject.h"
26#include "lldb/lldb-private.h"
27
28#include <sstream>
29
30using namespace lldb;
31using namespace lldb_private;
32
33LLDB_PLUGIN_DEFINE(MemoryHistoryASan)
34
35MemoryHistorySP MemoryHistoryASan::CreateInstance(const ProcessSP &process_sp) {
36 if (!process_sp.get())
37 return nullptr;
38
39 Target &target = process_sp->GetTarget();
40
41 for (ModuleSP module_sp : target.GetImages().Modules()) {
42 const Symbol *symbol = module_sp->FindFirstSymbolWithNameAndType(
43 name: ConstString("__asan_get_alloc_stack"), symbol_type: lldb::eSymbolTypeAny);
44
45 if (symbol != nullptr)
46 return MemoryHistorySP(new MemoryHistoryASan(process_sp));
47 }
48
49 return MemoryHistorySP();
50}
51
52void MemoryHistoryASan::Initialize() {
53 PluginManager::RegisterPlugin(
54 name: GetPluginNameStatic(), description: "ASan memory history provider.", create_callback: CreateInstance);
55}
56
57void MemoryHistoryASan::Terminate() {
58 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
59}
60
61MemoryHistoryASan::MemoryHistoryASan(const ProcessSP &process_sp) {
62 if (process_sp)
63 m_process_wp = process_sp;
64}
65
66const char *memory_history_asan_command_prefix = R"(
67 extern "C"
68 {
69 size_t __asan_get_alloc_stack(void *addr, void **trace, size_t size, int *thread_id);
70 size_t __asan_get_free_stack(void *addr, void **trace, size_t size, int *thread_id);
71 }
72)";
73
74const char *memory_history_asan_command_format =
75 R"(
76 struct {
77 void *alloc_trace[256];
78 size_t alloc_count;
79 int alloc_tid;
80
81 void *free_trace[256];
82 size_t free_count;
83 int free_tid;
84 } 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
94static 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(expression: count_path.c_str());
105 ValueObjectSP tid_sp =
106 return_value_sp->GetValueForExpressionPath(expression: tid_path.c_str());
107
108 if (!count_sp || !tid_sp)
109 return;
110
111 int count = count_sp->GetValueAsUnsigned(fail_value: 0);
112 lldb::tid_t tid = tid_sp->GetValueAsUnsigned(fail_value: 0) + 1;
113
114 if (count <= 0)
115 return;
116
117 ValueObjectSP trace_sp =
118 return_value_sp->GetValueForExpressionPath(expression: 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(idx: i)->GetValueAsUnsigned(fail_value: 0);
126 if (pc == 0 || pc == 1 || pc == LLDB_INVALID_ADDRESS)
127 continue;
128 pcs.push_back(x: 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(thread_sp: new_thread_sp);
144 result.push_back(x: new_thread_sp);
145}
146
147HistoryThreads 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 =
160 thread_sp->GetSelectedFrame(select_most_relevant: DoNoSelectMostRelevantFrame);
161 if (!frame_sp)
162 return result;
163
164 ExecutionContext exe_ctx(frame_sp);
165 ValueObjectSP return_value_sp;
166 StreamString expr;
167 expr.Printf(format: 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 if (auto m = GetPreferredAsanModule(target: process_sp->GetTarget())) {
180 SymbolContextList sc_list;
181 sc_list.Append(sc: SymbolContext(std::move(m)));
182 options.SetPreferredSymbolContexts(std::move(sc_list));
183 }
184
185 ExpressionResults expr_result = UserExpression::Evaluate(
186 exe_ctx, options, expr_cstr: expr.GetString(), expr_prefix: "", result_valobj_sp&: return_value_sp);
187 if (expr_result != eExpressionCompleted) {
188 StreamString ss;
189 ss << "cannot evaluate AddressSanitizer expression:\n";
190 if (return_value_sp)
191 ss << return_value_sp->GetError().AsCString();
192 Debugger::ReportWarning(message: ss.GetString().str(),
193 debugger_id: process_sp->GetTarget().GetDebugger().GetID());
194 return result;
195 }
196
197 if (!return_value_sp)
198 return result;
199
200 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, type: "free",
201 thread_name: "Memory deallocated by", result);
202 CreateHistoryThreadFromValueObject(process_sp, return_value_sp, type: "alloc",
203 thread_name: "Memory allocated by", result);
204
205 return result;
206}
207

source code of lldb/source/Plugins/MemoryHistory/asan/MemoryHistoryASan.cpp