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

//===-- MemoryHistoryASan.cpp -----------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "MemoryHistoryASan.h"

#include "lldb/Target/MemoryHistory.h"

#include "lldb/lldb-private.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Target/ThreadList.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Core/Module.h"
#include "Plugins/Process/Utility/HistoryThread.h"
#include "lldb/Core/ValueObject.h"

#include <sstream>

using namespace lldb;
using namespace lldb_private;

MemoryHistorySP
MemoryHistoryASan::CreateInstance (const ProcessSP &process_sp)
{
    if (!process_sp.get())
        return NULL;

    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);
    }
    
    HistoryThread *history_thread = new HistoryThread(*process_sp, tid, pcs, 0, false);
    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);
}

#define GET_STACK_FUNCTION_TIMEOUT_USEC 2*1000*1000

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;
    Error 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.SetTimeoutUsec(GET_STACK_FUNCTION_TIMEOUT_USEC);
    options.SetPrefix(memory_history_asan_command_prefix);
    options.SetAutoApplyFixIts(false);
    options.SetLanguage(eLanguageTypeObjC_plus_plus);

    ExpressionResults expr_result = UserExpression::Evaluate (exe_ctx,
                                      options,
                                      expr.GetData(),
                                      "",
                                      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;
}