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//===-- MemoryHistoryASan.cpp ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "MemoryHistoryASan.h"
#include "lldb/Target/MemoryHistory.h"
#include "Plugins/Process/Utility/HistoryThread.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadList.h"
#include "lldb/lldb-private.h"
#include <sstream>
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(MemoryHistoryASan)
MemoryHistorySP MemoryHistoryASan::CreateInstance(const ProcessSP &process_sp) {
if (!process_sp.get())
return nullptr;
Target &target = process_sp->GetTarget();
const ModuleList &target_modules = target.GetImages();
std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
const size_t num_modules = target_modules.GetSize();
for (size_t i = 0; i < num_modules; ++i) {
Module *module_pointer = target_modules.GetModulePointerAtIndexUnlocked(i);
const Symbol *symbol = module_pointer->FindFirstSymbolWithNameAndType(
ConstString("__asan_get_alloc_stack"), lldb::eSymbolTypeAny);
if (symbol != nullptr)
return MemoryHistorySP(new MemoryHistoryASan(process_sp));
}
return MemoryHistorySP();
}
void MemoryHistoryASan::Initialize() {
PluginManager::RegisterPlugin(
GetPluginNameStatic(), "ASan memory history provider.", CreateInstance);
}
void MemoryHistoryASan::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
ConstString MemoryHistoryASan::GetPluginNameStatic() {
static ConstString g_name("asan");
return g_name;
}
MemoryHistoryASan::MemoryHistoryASan(const ProcessSP &process_sp) {
if (process_sp)
m_process_wp = process_sp;
}
const char *memory_history_asan_command_prefix = R"(
extern "C"
{
size_t __asan_get_alloc_stack(void *addr, void **trace, size_t size, int *thread_id);
size_t __asan_get_free_stack(void *addr, void **trace, size_t size, int *thread_id);
}
struct data {
void *alloc_trace[256];
size_t alloc_count;
int alloc_tid;
void *free_trace[256];
size_t free_count;
int free_tid;
};
)";
const char *memory_history_asan_command_format =
R"(
data t;
t.alloc_count = __asan_get_alloc_stack((void *)0x%)" PRIx64
R"(, t.alloc_trace, 256, &t.alloc_tid);
t.free_count = __asan_get_free_stack((void *)0x%)" PRIx64
R"(, t.free_trace, 256, &t.free_tid);
t;
)";
static void CreateHistoryThreadFromValueObject(ProcessSP process_sp,
ValueObjectSP return_value_sp,
const char *type,
const char *thread_name,
HistoryThreads &result) {
std::string count_path = "." + std::string(type) + "_count";
std::string tid_path = "." + std::string(type) + "_tid";
std::string trace_path = "." + std::string(type) + "_trace";
ValueObjectSP count_sp =
return_value_sp->GetValueForExpressionPath(count_path.c_str());
ValueObjectSP tid_sp =
return_value_sp->GetValueForExpressionPath(tid_path.c_str());
if (!count_sp || !tid_sp)
return;
int count = count_sp->GetValueAsUnsigned(0);
tid_t tid = tid_sp->GetValueAsUnsigned(0) + 1;
if (count <= 0)
return;
ValueObjectSP trace_sp =
return_value_sp->GetValueForExpressionPath(trace_path.c_str());
if (!trace_sp)
return;
std::vector<lldb::addr_t> pcs;
for (int i = 0; i < count; i++) {
addr_t pc = trace_sp->GetChildAtIndex(i, true)->GetValueAsUnsigned(0);
if (pc == 0 || pc == 1 || pc == LLDB_INVALID_ADDRESS)
continue;
pcs.push_back(pc);
}
// The ASAN runtime already massages the return addresses into call
// addresses, we don't want LLDB's unwinder to try to locate the previous
// instruction again as this might lead to us reporting a different line.
bool pcs_are_call_addresses = true;
HistoryThread *history_thread =
new HistoryThread(*process_sp, tid, pcs, pcs_are_call_addresses);
ThreadSP new_thread_sp(history_thread);
std::ostringstream thread_name_with_number;
thread_name_with_number << thread_name << " Thread " << tid;
history_thread->SetThreadName(thread_name_with_number.str().c_str());
// Save this in the Process' ExtendedThreadList so a strong pointer retains
// the object
process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
result.push_back(new_thread_sp);
}
HistoryThreads MemoryHistoryASan::GetHistoryThreads(lldb::addr_t address) {
HistoryThreads result;
ProcessSP process_sp = m_process_wp.lock();
if (!process_sp)
return result;
ThreadSP thread_sp =
process_sp->GetThreadList().GetExpressionExecutionThread();
if (!thread_sp)
return result;
StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
if (!frame_sp)
return result;
ExecutionContext exe_ctx(frame_sp);
ValueObjectSP return_value_sp;
StreamString expr;
Status eval_error;
expr.Printf(memory_history_asan_command_format, address, address);
EvaluateExpressionOptions options;
options.SetUnwindOnError(true);
options.SetTryAllThreads(true);
options.SetStopOthers(true);
options.SetIgnoreBreakpoints(true);
options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
options.SetPrefix(memory_history_asan_command_prefix);
options.SetAutoApplyFixIts(false);
options.SetLanguage(eLanguageTypeObjC_plus_plus);
ExpressionResults expr_result = UserExpression::Evaluate(
exe_ctx, options, expr.GetString(), "", return_value_sp, eval_error);
if (expr_result != eExpressionCompleted) {
process_sp->GetTarget().GetDebugger().GetAsyncOutputStream()->Printf(
"Warning: Cannot evaluate AddressSanitizer expression:\n%s\n",
eval_error.AsCString());
return result;
}
if (!return_value_sp)
return result;
CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "free",
"Memory deallocated by", result);
CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "alloc",
"Memory allocated by", result);
return result;
}
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