llvm-project/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp

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

#include "NativeThreadLinux.h"

#include <signal.h>
#include <sstream>

#include "NativeProcessLinux.h"
#include "NativeRegisterContextLinux_x86_64.h"

#include "lldb/Core/Log.h"
#include "lldb/Core/State.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/HostInfo.h"
#include "lldb/Host/HostNativeThread.h"
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-private-log.h"

#include "llvm/ADT/SmallString.h"

#include "Plugins/Process/POSIX/CrashReason.h"

#include "Plugins/Process/Utility/RegisterContextLinux_arm64.h"
#include "Plugins/Process/Utility/RegisterContextLinux_i386.h"
#include "Plugins/Process/Utility/RegisterContextLinux_x86_64.h"
#include "Plugins/Process/Utility/RegisterInfoInterface.h"

using namespace lldb;
using namespace lldb_private;

namespace
{
    void LogThreadStopInfo (Log &log, const ThreadStopInfo &stop_info, const char *const header)
    {
        switch (stop_info.reason)
        {
            case eStopReasonSignal:
                log.Printf ("%s: %s signal 0x%02" PRIx32, __FUNCTION__, header, stop_info.details.signal.signo);
                return;
            case eStopReasonException:
                log.Printf ("%s: %s exception type 0x%02" PRIx64, __FUNCTION__, header, stop_info.details.exception.type);
                return;
            case eStopReasonExec:
                log.Printf ("%s: %s exec, stopping signal 0x%" PRIx32, __FUNCTION__, header, stop_info.details.signal.signo);
                return;
            default:
                log.Printf ("%s: %s invalid stop reason %" PRIu32, __FUNCTION__, header, static_cast<uint32_t> (stop_info.reason));
        }
    }
}

NativeThreadLinux::NativeThreadLinux (NativeProcessLinux *process, lldb::tid_t tid) :
    NativeThreadProtocol (process, tid),
    m_state (StateType::eStateInvalid),
    m_stop_info (),
    m_reg_context_sp (),
    m_stop_description ()
{
}

std::string
NativeThreadLinux::GetName()
{
    NativeProcessProtocolSP process_sp = m_process_wp.lock ();
    if (!process_sp)
        return "<unknown: no process>";

    // const NativeProcessLinux *const process = reinterpret_cast<NativeProcessLinux*> (process_sp->get ());
    llvm::SmallString<32> thread_name;
    HostNativeThread::GetName(GetID(), thread_name);
    return thread_name.c_str();
}

lldb::StateType
NativeThreadLinux::GetState ()
{
    return m_state;
}


bool
NativeThreadLinux::GetStopReason (ThreadStopInfo &stop_info, std::string& description)
{
    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD));

    description.clear();

    switch (m_state)
    {
    case eStateStopped:
    case eStateCrashed:
    case eStateExited:
    case eStateSuspended:
    case eStateUnloaded:
        if (log)
            LogThreadStopInfo (*log, m_stop_info, "m_stop_info in thread:");
        stop_info = m_stop_info;
        switch (m_stop_info.reason)
        {
            case StopReason::eStopReasonException:
            case StopReason::eStopReasonBreakpoint:
            case StopReason::eStopReasonWatchpoint:
                description = m_stop_description;
            default:
                break;
        }
        if (log)
            LogThreadStopInfo (*log, stop_info, "returned stop_info:");

        return true;

    case eStateInvalid:
    case eStateConnected:
    case eStateAttaching:
    case eStateLaunching:
    case eStateRunning:
    case eStateStepping:
    case eStateDetached:
        if (log)
        {
            log->Printf ("NativeThreadLinux::%s tid %" PRIu64 " in state %s cannot answer stop reason",
                    __FUNCTION__, GetID (), StateAsCString (m_state));
        }
        return false;
    }
    llvm_unreachable("unhandled StateType!");
}

lldb_private::NativeRegisterContextSP
NativeThreadLinux::GetRegisterContext ()
{
    // Return the register context if we already created it.
    if (m_reg_context_sp)
        return m_reg_context_sp;

    // First select the appropriate RegisterInfoInterface.
    RegisterInfoInterface *reg_interface = nullptr;
    NativeProcessProtocolSP m_process_sp = m_process_wp.lock ();
    if (!m_process_sp)
        return NativeRegisterContextSP ();

    ArchSpec target_arch;
    if (!m_process_sp->GetArchitecture (target_arch))
        return NativeRegisterContextSP ();

    switch (target_arch.GetTriple().getOS())
    {
        case llvm::Triple::Linux:
            switch (target_arch.GetMachine())
            {
            case llvm::Triple::aarch64:
                assert((HostInfo::GetArchitecture ().GetAddressByteSize() == 8) && "Register setting path assumes this is a 64-bit host");
                reg_interface = static_cast<RegisterInfoInterface*>(new RegisterContextLinux_arm64(target_arch));
                break;
            case llvm::Triple::x86:
            case llvm::Triple::x86_64:
                if (HostInfo::GetArchitecture().GetAddressByteSize() == 4)
                {
                    // 32-bit hosts run with a RegisterContextLinux_i386 context.
                    reg_interface = static_cast<RegisterInfoInterface*>(new RegisterContextLinux_i386(target_arch));
                }
                else
                {
                    assert((HostInfo::GetArchitecture().GetAddressByteSize() == 8) &&
                           "Register setting path assumes this is a 64-bit host");
                    // X86_64 hosts know how to work with 64-bit and 32-bit EXEs using the x86_64 register context.
                    reg_interface = static_cast<RegisterInfoInterface*> (new RegisterContextLinux_x86_64 (target_arch));
                }
                break;
            default:
                break;
            }
            break;
        default:
            break;
    }

    assert(reg_interface && "OS or CPU not supported!");
    if (!reg_interface)
        return NativeRegisterContextSP ();

    // Now create the register context.
    switch (target_arch.GetMachine())
    {
#if 0
        case llvm::Triple::mips64:
        {
            RegisterContextPOSIXProcessMonitor_mips64 *reg_ctx = new RegisterContextPOSIXProcessMonitor_mips64(*this, 0, reg_interface);
            m_posix_thread = reg_ctx;
            m_reg_context_sp.reset(reg_ctx);
            break;
        }
#endif

        case llvm::Triple::x86:
        case llvm::Triple::x86_64:
        {
            const uint32_t concrete_frame_idx = 0;
            m_reg_context_sp.reset (new NativeRegisterContextLinux_x86_64(*this, concrete_frame_idx, reg_interface));
            break;
        }
        default:
            break;
    }

    return m_reg_context_sp;
}

Error
NativeThreadLinux::SetWatchpoint (lldb::addr_t addr, size_t size, uint32_t watch_flags, bool hardware)
{
    if (!hardware)
        return Error ("not implemented");
    Error error = RemoveWatchpoint(addr);
    if (error.Fail()) return error;
    NativeRegisterContextSP reg_ctx = GetRegisterContext ();
    uint32_t wp_index =
        reg_ctx->SetHardwareWatchpoint (addr, size, watch_flags);
    if (wp_index == LLDB_INVALID_INDEX32)
        return Error ("Setting hardware watchpoint failed.");
    m_watchpoint_index_map.insert({addr, wp_index});
    return Error ();
}

Error
NativeThreadLinux::RemoveWatchpoint (lldb::addr_t addr)
{
    auto wp = m_watchpoint_index_map.find(addr);
    if (wp == m_watchpoint_index_map.end())
        return Error ();
    uint32_t wp_index = wp->second;
    m_watchpoint_index_map.erase(wp);
    if (GetRegisterContext()->ClearHardwareWatchpoint(wp_index))
        return Error ();
    return Error ("Clearing hardware watchpoint failed.");
}

void
NativeThreadLinux::SetLaunching ()
{
    const StateType new_state = StateType::eStateLaunching;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    // Also mark it as stopped since launching temporarily stops the newly created thread
    // in the ptrace machinery.
    m_stop_info.reason = StopReason::eStopReasonSignal;
    m_stop_info.details.signal.signo = SIGSTOP;
}


void
NativeThreadLinux::SetRunning ()
{
    const StateType new_state = StateType::eStateRunning;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonNone;
    m_stop_description.clear();

    // If watchpoints have been set, but none on this thread,
    // then this is a new thread. So set all existing watchpoints.
    if (m_watchpoint_index_map.empty())
    {
        const auto process_sp = GetProcess();
        if (process_sp)
        {
            const auto &watchpoint_map = process_sp->GetWatchpointMap();
            if (watchpoint_map.empty()) return;
            GetRegisterContext()->ClearAllHardwareWatchpoints();
            for (const auto &pair : watchpoint_map)
            {
                const auto& wp = pair.second;
                SetWatchpoint(wp.m_addr, wp.m_size, wp.m_watch_flags, wp.m_hardware);
            }
        }
    }
}

void
NativeThreadLinux::SetStepping ()
{
    const StateType new_state = StateType::eStateStepping;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonNone;
}

void
NativeThreadLinux::SetStoppedBySignal (uint32_t signo)
{
    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD));
    if (log)
        log->Printf ("NativeThreadLinux::%s called with signal 0x%02" PRIx32, __FUNCTION__, signo);

    const StateType new_state = StateType::eStateStopped;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonSignal;
    m_stop_info.details.signal.signo = signo;
}

bool
NativeThreadLinux::IsStopped (int *signo)
{
    if (!StateIsStoppedState (m_state, false))
        return false;

    // If we are stopped by a signal, return the signo.
    if (signo &&
        m_state == StateType::eStateStopped &&
        m_stop_info.reason == StopReason::eStopReasonSignal)
    {
        *signo = m_stop_info.details.signal.signo;
    }

    // Regardless, we are stopped.
    return true;
}


void
NativeThreadLinux::SetStoppedByExec ()
{
    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD));
    if (log)
        log->Printf ("NativeThreadLinux::%s()", __FUNCTION__);

    const StateType new_state = StateType::eStateStopped;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonExec;
    m_stop_info.details.signal.signo = SIGSTOP;
}

void
NativeThreadLinux::SetStoppedByBreakpoint ()
{
    const StateType new_state = StateType::eStateStopped;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonBreakpoint;
    m_stop_info.details.signal.signo = SIGTRAP;
    m_stop_description.clear();
}

void
NativeThreadLinux::SetStoppedByWatchpoint ()
{
    const StateType new_state = StateType::eStateStopped;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonWatchpoint;
    m_stop_info.details.signal.signo = SIGTRAP;

    NativeRegisterContextLinux_x86_64 *reg_ctx =
        reinterpret_cast<NativeRegisterContextLinux_x86_64*> (GetRegisterContext().get());
    const uint32_t num_hw_watchpoints =
        reg_ctx->NumSupportedHardwareWatchpoints();

    m_stop_description.clear ();
    for (uint32_t wp_index = 0; wp_index < num_hw_watchpoints; ++wp_index)
        if (reg_ctx->IsWatchpointHit(wp_index).Success())
        {
            std::ostringstream ostr;
            ostr << reg_ctx->GetWatchpointAddress(wp_index) << " " << wp_index;
            m_stop_description = ostr.str();
            return;
        }
    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD));
    if (log)
    {
        NativeProcessProtocolSP m_process_sp = m_process_wp.lock ();
        lldb::pid_t pid = m_process_sp ? m_process_sp->GetID () : LLDB_INVALID_PROCESS_ID;
        log->Printf ("NativeThreadLinux: thread (pid=%" PRIu64 ", tid=%" PRIu64 ") "
                "stopped by a watchpoint, but failed to find it",
                pid, GetID ());
    }
}

bool
NativeThreadLinux::IsStoppedAtBreakpoint ()
{
    return GetState () == StateType::eStateStopped &&
        m_stop_info.reason == StopReason::eStopReasonBreakpoint;
}

bool
NativeThreadLinux::IsStoppedAtWatchpoint ()
{
    return GetState () == StateType::eStateStopped &&
        m_stop_info.reason == StopReason::eStopReasonWatchpoint;
}

void
NativeThreadLinux::SetStoppedByTrace ()
{
    const StateType new_state = StateType::eStateStopped;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonTrace;
    m_stop_info.details.signal.signo = SIGTRAP;
}

void
NativeThreadLinux::SetCrashedWithException (const siginfo_t& info)
{
    const StateType new_state = StateType::eStateCrashed;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonException;
    m_stop_info.details.signal.signo = info.si_signo;

    const auto reason = GetCrashReason (info);
    m_stop_description = GetCrashReasonString (reason, reinterpret_cast<lldb::addr_t> (info.si_addr));
}

void
NativeThreadLinux::SetSuspended ()
{
    const StateType new_state = StateType::eStateSuspended;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    // FIXME what makes sense here? Do we need a suspended StopReason?
    m_stop_info.reason = StopReason::eStopReasonNone;
}

void
NativeThreadLinux::SetExited ()
{
    const StateType new_state = StateType::eStateExited;
    MaybeLogStateChange (new_state);
    m_state = new_state;

    m_stop_info.reason = StopReason::eStopReasonThreadExiting;
}

void
NativeThreadLinux::MaybeLogStateChange (lldb::StateType new_state)
{
    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD));
    // If we're not logging, we're done.
    if (!log)
        return;

    // If this is a state change to the same state, we're done.
    lldb::StateType old_state = m_state;
    if (new_state == old_state)
        return;

    NativeProcessProtocolSP m_process_sp = m_process_wp.lock ();
    lldb::pid_t pid = m_process_sp ? m_process_sp->GetID () : LLDB_INVALID_PROCESS_ID;

    // Log it.
    log->Printf ("NativeThreadLinux: thread (pid=%" PRIu64 ", tid=%" PRIu64 ") changing from state %s to %s", pid, GetID (), StateAsCString (old_state), StateAsCString (new_state));
}