xref: /llvm-project-15.0.7/lldb/source/Plugins/Process/mach-core/ThreadMachCore.cpp (revision 3b14d80a)

//===-- ThreadMachCore.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 "ThreadMachCore.h"

#include "lldb/Breakpoint/Watchpoint.h"
#include "lldb/Host/SafeMachO.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/AppleArm64ExceptionClass.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Unwind.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/RegisterValue.h"
#include "lldb/Utility/State.h"
#include "lldb/Utility/StreamString.h"

#include "ProcessMachCore.h"
//#include "RegisterContextKDP_arm.h"
//#include "RegisterContextKDP_i386.h"
//#include "RegisterContextKDP_x86_64.h"

using namespace lldb;
using namespace lldb_private;

// Thread Registers

ThreadMachCore::ThreadMachCore(Process &process, lldb::tid_t tid)
    : Thread(process, tid), m_thread_name(), m_dispatch_queue_name(),
      m_thread_dispatch_qaddr(LLDB_INVALID_ADDRESS), m_thread_reg_ctx_sp() {}

ThreadMachCore::~ThreadMachCore() { DestroyThread(); }

const char *ThreadMachCore::GetName() {
  if (m_thread_name.empty())
    return nullptr;
  return m_thread_name.c_str();
}

void ThreadMachCore::RefreshStateAfterStop() {
  // Invalidate all registers in our register context. We don't set "force" to
  // true because the stop reply packet might have had some register values
  // that were expedited and these will already be copied into the register
  // context by the time this function gets called. The KDPRegisterContext
  // class has been made smart enough to detect when it needs to invalidate
  // which registers are valid by putting hooks in the register read and
  // register supply functions where they check the process stop ID and do the
  // right thing.
  const bool force = false;
  GetRegisterContext()->InvalidateIfNeeded(force);
}

bool ThreadMachCore::ThreadIDIsValid(lldb::tid_t thread) { return thread != 0; }

lldb::RegisterContextSP ThreadMachCore::GetRegisterContext() {
  if (!m_reg_context_sp)
    m_reg_context_sp = CreateRegisterContextForFrame(nullptr);
  return m_reg_context_sp;
}

lldb::RegisterContextSP
ThreadMachCore::CreateRegisterContextForFrame(StackFrame *frame) {
  lldb::RegisterContextSP reg_ctx_sp;
  uint32_t concrete_frame_idx = 0;

  if (frame)
    concrete_frame_idx = frame->GetConcreteFrameIndex();

  if (concrete_frame_idx == 0) {
    if (!m_thread_reg_ctx_sp) {
      ProcessSP process_sp(GetProcess());

      ObjectFile *core_objfile =
          static_cast<ProcessMachCore *>(process_sp.get())->GetCoreObjectFile();
      if (core_objfile)
        m_thread_reg_ctx_sp =
            core_objfile->GetThreadContextAtIndex(GetID(), *this);
    }
    reg_ctx_sp = m_thread_reg_ctx_sp;
  } else {
    reg_ctx_sp = GetUnwinder().CreateRegisterContextForFrame(frame);
  }
  return reg_ctx_sp;
}

static bool IsCrashExceptionClass(AppleArm64ExceptionClass EC) {
  switch (EC) {
  case AppleArm64ExceptionClass::ESR_EC_UNCATEGORIZED:
  case AppleArm64ExceptionClass::ESR_EC_SVC_32:
  case AppleArm64ExceptionClass::ESR_EC_SVC_64:
    // In the ARM exception model, a process takes an exception when asking the
    // kernel to service a system call. Don't treat this like a crash.
    return false;
  default:
    return true;
  }
}

bool ThreadMachCore::CalculateStopInfo() {
  ProcessSP process_sp(GetProcess());
  if (process_sp) {
    StopInfoSP stop_info;
    RegisterContextSP reg_ctx_sp = GetRegisterContext();

    if (reg_ctx_sp) {
      Target &target = process_sp->GetTarget();
      const ArchSpec arch_spec = target.GetArchitecture();
      const uint32_t cputype = arch_spec.GetMachOCPUType();

      if (cputype == llvm::MachO::CPU_TYPE_ARM64 ||
          cputype == llvm::MachO::CPU_TYPE_ARM64_32) {
        const RegisterInfo *esr_info = reg_ctx_sp->GetRegisterInfoByName("esr");
        const RegisterInfo *far_info = reg_ctx_sp->GetRegisterInfoByName("far");
        RegisterValue esr, far;
        if (reg_ctx_sp->ReadRegister(esr_info, esr) &&
            reg_ctx_sp->ReadRegister(far_info, far)) {
          const uint32_t esr_val = esr.GetAsUInt32();
          const AppleArm64ExceptionClass exception_class =
              getAppleArm64ExceptionClass(esr_val);
          if (IsCrashExceptionClass(exception_class)) {
            StreamString S;
            S.Printf("%s (fault address: 0x%" PRIx64 ")",
                     toString(exception_class), far.GetAsUInt64());
            stop_info =
                StopInfo::CreateStopReasonWithException(*this, S.GetData());
          }
        }
      }
    }

    // Set a stop reason for crashing threads only so that they get selected
    // preferentially.
    if (stop_info)
      SetStopInfo(stop_info);
    return true;
  }
  return false;
}