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/PluginInterface.h"
#include "lldb/Core/PluginManager.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"

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();
    Mutex::Locker modules_locker(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_format = R"(
    struct t {
        void *alloc_trace[256];
        size_t alloc_count;
        int alloc_tid;
        
        void *free_trace[256];
        size_t free_count;
        int free_tid;
    } t;

    t.alloc_count = ((size_t (*) (void *, void **, size_t, int *))__asan_get_alloc_stack)((void *)0x%)" PRIx64 R"(, t.alloc_trace, 256, &t.alloc_tid);
    t.free_count = ((size_t (*) (void *, void **, size_t, int *))__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);

    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);
    // let's use thread name for the type of history thread, since history threads don't have names anyway
    history_thread->SetThreadName(thread_name);
    // 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)
    {
        ThreadSP thread_sp = process_sp->GetThreadList().GetSelectedThread();

        if (thread_sp)
        {
            StackFrameSP frame_sp = thread_sp->GetSelectedFrame();

            if (frame_sp)
            {
                ExecutionContext exe_ctx (frame_sp);
                ValueObjectSP return_value_sp;
                StreamString expr;
                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);

                if (process_sp->GetTarget().EvaluateExpression(expr.GetData(), frame_sp.get(), return_value_sp, options) == eExpressionCompleted)
                {
                    if (return_value_sp)
                    {
                        CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "free", "Memory deallocated at", result);
                        CreateHistoryThreadFromValueObject(process_sp, return_value_sp, "alloc", "Memory allocated at", result);
                    }
                }
            }
        }
    }
    return result;
}