llvm-capstone/lldb/source/Target/ThreadPlanStepOverBreakpoint.cpp

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

#include "lldb/Target/ThreadPlanStepOverBreakpoint.h"

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Core/Log.h"
#include "lldb/Core/Stream.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"

using namespace lldb;
using namespace lldb_private;

//----------------------------------------------------------------------
// ThreadPlanStepOverBreakpoint: Single steps over a breakpoint bp_site_sp at
// the pc.
//----------------------------------------------------------------------

ThreadPlanStepOverBreakpoint::ThreadPlanStepOverBreakpoint(Thread &thread)
    : ThreadPlan(
          ThreadPlan::eKindStepOverBreakpoint, "Step over breakpoint trap",
          thread, eVoteNo,
          eVoteNoOpinion), // We need to report the run since this happens
                           // first in the thread plan stack when stepping
                           // over a breakpoint
      m_breakpoint_addr(LLDB_INVALID_ADDRESS),
      m_auto_continue(false), m_reenabled_breakpoint_site(false)

{
  m_breakpoint_addr = m_thread.GetRegisterContext()->GetPC();
  m_breakpoint_site_id =
      m_thread.GetProcess()->GetBreakpointSiteList().FindIDByAddress(
          m_breakpoint_addr);
}

ThreadPlanStepOverBreakpoint::~ThreadPlanStepOverBreakpoint() {}

void ThreadPlanStepOverBreakpoint::GetDescription(
    Stream *s, lldb::DescriptionLevel level) {
  s->Printf("Single stepping past breakpoint site %" PRIu64 " at 0x%" PRIx64,
            m_breakpoint_site_id, (uint64_t)m_breakpoint_addr);
}

bool ThreadPlanStepOverBreakpoint::ValidatePlan(Stream *error) { return true; }

bool ThreadPlanStepOverBreakpoint::DoPlanExplainsStop(Event *event_ptr) {
  StopInfoSP stop_info_sp = GetPrivateStopInfo();
  if (stop_info_sp) {
    // It's a little surprising that we stop here for a breakpoint hit.
    // However, when you single step ONTO a breakpoint
    // we still want to call that a breakpoint hit, and trigger the actions,
    // etc.  Otherwise you would see the
    // PC at the breakpoint without having triggered the actions, then you'd
    // continue, the PC wouldn't change,
    // and you'd see the breakpoint hit, which would be odd.
    // So the lower levels fake "step onto breakpoint address" and return that
    // as a breakpoint.  So our trace
    // step COULD appear as a breakpoint hit if the next instruction also
    // contained a breakpoint.
    StopReason reason = stop_info_sp->GetStopReason();

    switch (reason) {
    case eStopReasonTrace:
    case eStopReasonNone:
      return true;
    case eStopReasonBreakpoint:
      // It's a little surprising that we stop here for a breakpoint hit.
      // However, when you single step ONTO a
      // breakpoint we still want to call that a breakpoint hit, and trigger the
      // actions, etc.  Otherwise you
      // would see the PC at the breakpoint without having triggered the
      // actions, then you'd continue, the PC
      // wouldn't change, and you'd see the breakpoint hit, which would be odd.
      // So the lower levels fake "step onto breakpoint address" and return that
      // as a breakpoint hit.  So our trace
      // step COULD appear as a breakpoint hit if the next instruction also
      // contained a breakpoint.  We don't want
      // to handle that, since we really don't know what to do with breakpoint
      // hits.  But make sure we don't set
      // ourselves to auto-continue or we'll wrench control away from the plans
      // that can deal with this.
      SetAutoContinue(false);
      return false;
    default:
      return false;
    }
  }
  return false;
}

bool ThreadPlanStepOverBreakpoint::ShouldStop(Event *event_ptr) {
  return !ShouldAutoContinue(event_ptr);
}

bool ThreadPlanStepOverBreakpoint::StopOthers() { return true; }

StateType ThreadPlanStepOverBreakpoint::GetPlanRunState() {
  return eStateStepping;
}

bool ThreadPlanStepOverBreakpoint::DoWillResume(StateType resume_state,
                                                bool current_plan) {
  if (current_plan) {
    BreakpointSiteSP bp_site_sp(
        m_thread.GetProcess()->GetBreakpointSiteList().FindByAddress(
            m_breakpoint_addr));
    if (bp_site_sp && bp_site_sp->IsEnabled())
      m_thread.GetProcess()->DisableBreakpointSite(bp_site_sp.get());
  }
  return true;
}

bool ThreadPlanStepOverBreakpoint::WillStop() {
  ReenableBreakpointSite();
  return true;
}

bool ThreadPlanStepOverBreakpoint::MischiefManaged() {
  lldb::addr_t pc_addr = m_thread.GetRegisterContext()->GetPC();

  if (pc_addr == m_breakpoint_addr) {
    // If we are still at the PC of our breakpoint, then for some reason we
    // didn't
    // get a chance to run.
    return false;
  } else {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    if (log)
      log->Printf("Completed step over breakpoint plan.");
    // Otherwise, re-enable the breakpoint we were stepping over, and we're
    // done.
    ReenableBreakpointSite();
    ThreadPlan::MischiefManaged();
    return true;
  }
}

void ThreadPlanStepOverBreakpoint::ReenableBreakpointSite() {
  if (!m_reenabled_breakpoint_site) {
    m_reenabled_breakpoint_site = true;
    BreakpointSiteSP bp_site_sp(
        m_thread.GetProcess()->GetBreakpointSiteList().FindByAddress(
            m_breakpoint_addr));
    if (bp_site_sp) {
      m_thread.GetProcess()->EnableBreakpointSite(bp_site_sp.get());
    }
  }
}
void ThreadPlanStepOverBreakpoint::ThreadDestroyed() {
  ReenableBreakpointSite();
}

void ThreadPlanStepOverBreakpoint::SetAutoContinue(bool do_it) {
  m_auto_continue = do_it;
}

bool ThreadPlanStepOverBreakpoint::ShouldAutoContinue(Event *event_ptr) {
  return m_auto_continue;
}

bool ThreadPlanStepOverBreakpoint::IsPlanStale() {
  return m_thread.GetRegisterContext()->GetPC() != m_breakpoint_addr;
}