llvm-project/lldb/source/Target/ThreadPlanStepInRange.cpp

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

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Target/ThreadPlanStepInRange.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/Stream.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlanStepOut.h"
#include "lldb/Target/ThreadPlanStepThrough.h"
#include "lldb/Core/RegularExpression.h"

using namespace lldb;
using namespace lldb_private;

uint32_t ThreadPlanStepInRange::s_default_flag_values = ThreadPlanShouldStopHere::eStepInAvoidNoDebug;

//----------------------------------------------------------------------
// ThreadPlanStepInRange: Step through a stack range, either stepping over or into
// based on the value of \a type.
//----------------------------------------------------------------------

ThreadPlanStepInRange::ThreadPlanStepInRange
(
    Thread &thread,
    const AddressRange &range,
    const SymbolContext &addr_context,
    lldb::RunMode stop_others,
    LazyBool step_in_avoids_code_without_debug_info,
    LazyBool step_out_avoids_code_without_debug_info
) :
    ThreadPlanStepRange (ThreadPlan::eKindStepInRange, "Step Range stepping in", thread, range, addr_context, stop_others),
    ThreadPlanShouldStopHere (this),
    m_step_past_prologue (true),
    m_virtual_step (false)
{
    SetCallbacks();
    SetFlagsToDefault ();
    SetupAvoidNoDebug(step_in_avoids_code_without_debug_info, step_out_avoids_code_without_debug_info);
}

ThreadPlanStepInRange::ThreadPlanStepInRange
(
    Thread &thread,
    const AddressRange &range,
    const SymbolContext &addr_context,
    const char *step_into_target,
    lldb::RunMode stop_others,
    LazyBool step_in_avoids_code_without_debug_info,
    LazyBool step_out_avoids_code_without_debug_info
) :
    ThreadPlanStepRange (ThreadPlan::eKindStepInRange, "Step Range stepping in", thread, range, addr_context, stop_others),
    ThreadPlanShouldStopHere (this),
    m_step_past_prologue (true),
    m_virtual_step (false),
    m_step_into_target (step_into_target)
{
    SetCallbacks();
    SetFlagsToDefault ();
    SetupAvoidNoDebug(step_in_avoids_code_without_debug_info, step_out_avoids_code_without_debug_info);
}

ThreadPlanStepInRange::~ThreadPlanStepInRange() = default;

void
ThreadPlanStepInRange::SetupAvoidNoDebug(LazyBool step_in_avoids_code_without_debug_info,
                                         LazyBool step_out_avoids_code_without_debug_info)
{
    bool avoid_nodebug = true;
    
    switch (step_in_avoids_code_without_debug_info)
    {
        case eLazyBoolYes:
            avoid_nodebug = true;
            break;
        case eLazyBoolNo:
            avoid_nodebug = false;
            break;
        case eLazyBoolCalculate:
            avoid_nodebug = m_thread.GetStepInAvoidsNoDebug();
            break;
    }
    if (avoid_nodebug)
        GetFlags().Set (ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
    else
        GetFlags().Clear (ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
    
    switch (step_out_avoids_code_without_debug_info)
    {
        case eLazyBoolYes:
            avoid_nodebug = true;
            break;
        case eLazyBoolNo:
            avoid_nodebug = false;
            break;
        case eLazyBoolCalculate:
            avoid_nodebug = m_thread.GetStepOutAvoidsNoDebug();
            break;
    }
    if (avoid_nodebug)
        GetFlags().Set (ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
    else
        GetFlags().Clear (ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
}

void
ThreadPlanStepInRange::GetDescription (Stream *s, lldb::DescriptionLevel level)
{
    if (level == lldb::eDescriptionLevelBrief)
    {
        s->Printf("step in");
        return;
    }

    s->Printf ("Stepping in");
    bool printed_line_info = false;
    if (m_addr_context.line_entry.IsValid())
    {
        s->Printf (" through line ");
        m_addr_context.line_entry.DumpStopContext (s, false);
        printed_line_info = true;
    }

    const char *step_into_target = m_step_into_target.AsCString();
    if (step_into_target && step_into_target[0] != '\0')
        s->Printf (" targeting %s", m_step_into_target.AsCString());

    if (!printed_line_info || level == eDescriptionLevelVerbose)
    {
        s->Printf (" using ranges:");
        DumpRanges(s);
    }

    s->PutChar('.');
}

bool
ThreadPlanStepInRange::ShouldStop (Event *event_ptr)
{
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
    
    if (log)
    {
        StreamString s;
        s.Address (m_thread.GetRegisterContext()->GetPC(), 
                   m_thread.CalculateTarget()->GetArchitecture().GetAddressByteSize());
        log->Printf("ThreadPlanStepInRange reached %s.", s.GetData());
    }

    if (IsPlanComplete())
        return true;
        
    m_no_more_plans = false;
    if (m_sub_plan_sp && m_sub_plan_sp->IsPlanComplete())
    {
        if (!m_sub_plan_sp->PlanSucceeded())
        {
            SetPlanComplete();
            m_no_more_plans = true;
            return true;
        }
        else
            m_sub_plan_sp.reset();
    }
    
    if (m_virtual_step)
    {
        // If we've just completed a virtual step, all we need to do is check for a ShouldStopHere plan, and otherwise
        // we're done.
        // FIXME - This can be both a step in and a step out.  Probably should record which in the m_virtual_step.
        m_sub_plan_sp = CheckShouldStopHereAndQueueStepOut(eFrameCompareYounger);
    }
    else
    {
        // Stepping through should be done running other threads in general, since we're setting a breakpoint and
        // continuing.  So only stop others if we are explicitly told to do so.
        
        bool stop_others = (m_stop_others == lldb::eOnlyThisThread);
            
        FrameComparison frame_order = CompareCurrentFrameToStartFrame();
        
        if (frame_order == eFrameCompareOlder || frame_order == eFrameCompareSameParent)
        {
            // If we're in an older frame then we should stop.
            //
            // A caveat to this is if we think the frame is older but we're actually in a trampoline.
            // I'm going to make the assumption that you wouldn't RETURN to a trampoline.  So if we are
            // in a trampoline we think the frame is older because the trampoline confused the backtracer.
            m_sub_plan_sp = m_thread.QueueThreadPlanForStepThrough (m_stack_id, false, stop_others);
            if (!m_sub_plan_sp)
            {
                // Otherwise check the ShouldStopHere for step out:
                m_sub_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order);
                if (log)
                    log->Printf ("ShouldStopHere says we should step out of this frame.");
            }
            else if (log)
            {
                log->Printf("Thought I stepped out, but in fact arrived at a trampoline.");
            }
        }
        else if (frame_order == eFrameCompareEqual && InSymbol())
        {
            // If we are not in a place we should step through, we're done.
            // One tricky bit here is that some stubs don't push a frame, so we have to check
            // both the case of a frame that is younger, or the same as this frame.  
            // However, if the frame is the same, and we are still in the symbol we started
            // in, the we don't need to do this.  This first check isn't strictly necessary,
            // but it is more efficient.
            
            // If we're still in the range, keep going, either by running to the next branch breakpoint, or by
            // stepping.
            if (InRange())
            {
                SetNextBranchBreakpoint();
                return false;
            }
        
            SetPlanComplete();
            m_no_more_plans = true;
            return true;
        }
        
        // If we get to this point, we're not going to use a previously set "next branch" breakpoint, so delete it:
        ClearNextBranchBreakpoint();
        
        // We may have set the plan up above in the FrameIsOlder section:
        
        if (!m_sub_plan_sp)
            m_sub_plan_sp = m_thread.QueueThreadPlanForStepThrough (m_stack_id, false, stop_others);
        
        if (log)
        {
            if (m_sub_plan_sp)
                log->Printf ("Found a step through plan: %s", m_sub_plan_sp->GetName());
            else
                log->Printf ("No step through plan found.");
        }
        
        // If not, give the "should_stop" callback a chance to push a plan to get us out of here.
        // But only do that if we actually have stepped in.
        if (!m_sub_plan_sp && frame_order == eFrameCompareYounger)
            m_sub_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order);

        // If we've stepped in and we are going to stop here, check to see if we were asked to
        // run past the prologue, and if so do that.
        
        if (!m_sub_plan_sp && frame_order == eFrameCompareYounger && m_step_past_prologue)
        {
            lldb::StackFrameSP curr_frame = m_thread.GetStackFrameAtIndex(0);
            if (curr_frame)
            {
                size_t bytes_to_skip = 0;
                lldb::addr_t curr_addr = m_thread.GetRegisterContext()->GetPC();
                Address func_start_address;
                
                SymbolContext sc = curr_frame->GetSymbolContext (eSymbolContextFunction | eSymbolContextSymbol);
                
                if (sc.function)
                {
                    func_start_address = sc.function->GetAddressRange().GetBaseAddress();
                    if (curr_addr == func_start_address.GetLoadAddress(m_thread.CalculateTarget().get()))
                        bytes_to_skip = sc.function->GetPrologueByteSize();
                }
                else if (sc.symbol)
                {
                    func_start_address = sc.symbol->GetAddress();
                    if (curr_addr == func_start_address.GetLoadAddress(m_thread.CalculateTarget().get()))
                        bytes_to_skip = sc.symbol->GetPrologueByteSize();
                }
                
                if (bytes_to_skip != 0)
                {
                    func_start_address.Slide (bytes_to_skip);
                    log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);
                    if (log)
                        log->Printf ("Pushing past prologue ");
                        
                    m_sub_plan_sp = m_thread.QueueThreadPlanForRunToAddress(false, func_start_address,true);
                }
            }
        }
     }
    
     if (!m_sub_plan_sp)
     {
        m_no_more_plans = true;
        SetPlanComplete();
        return true;
    }
    else
    {
        m_no_more_plans = false;
        m_sub_plan_sp->SetPrivate(true);
        return false;
    }
}

void 
ThreadPlanStepInRange::SetAvoidRegexp(const char *name)
{
    if (!m_avoid_regexp_ap)
        m_avoid_regexp_ap.reset (new RegularExpression(name));

    m_avoid_regexp_ap->Compile (name);
}

void
ThreadPlanStepInRange::SetDefaultFlagValue (uint32_t new_value)
{
    // TODO: Should we test this for sanity?
    ThreadPlanStepInRange::s_default_flag_values = new_value;
}

bool
ThreadPlanStepInRange::FrameMatchesAvoidCriteria ()
{
    StackFrame *frame = GetThread().GetStackFrameAtIndex(0).get();
    
    // Check the library list first, as that's cheapest:
    bool libraries_say_avoid = false;

    FileSpecList libraries_to_avoid (GetThread().GetLibrariesToAvoid());
    size_t num_libraries = libraries_to_avoid.GetSize();
    if (num_libraries > 0)
    {
        SymbolContext sc(frame->GetSymbolContext(eSymbolContextModule));
        FileSpec frame_library(sc.module_sp->GetFileSpec());
        
        if (frame_library)
        {
            for (size_t i = 0; i < num_libraries; i++)
            {
                const FileSpec &file_spec(libraries_to_avoid.GetFileSpecAtIndex(i));
                if (FileSpec::Equal (file_spec, frame_library, false))
                {
                    libraries_say_avoid = true;
                    break;
                }
            }
        }
    }
    if (libraries_say_avoid)
        return true;
    
    const RegularExpression *avoid_regexp_to_use = m_avoid_regexp_ap.get();
    if (avoid_regexp_to_use == nullptr)
        avoid_regexp_to_use = GetThread().GetSymbolsToAvoidRegexp();
        
    if (avoid_regexp_to_use != nullptr)
    {
        SymbolContext sc = frame->GetSymbolContext(eSymbolContextFunction|eSymbolContextBlock|eSymbolContextSymbol);
        if (sc.symbol != nullptr)
        {
            const char *frame_function_name = sc.GetFunctionName(Mangled::ePreferDemangledWithoutArguments).GetCString();
            if (frame_function_name)
            {
                size_t num_matches = 0;
                Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
                if (log)
                    num_matches = 1;
                
                RegularExpression::Match regex_match(num_matches);

                bool return_value = avoid_regexp_to_use->Execute(frame_function_name, &regex_match);
                if (return_value)
                {
                    if (log)
                    {
                        std::string match;
                        regex_match.GetMatchAtIndex(frame_function_name,0, match);
                        log->Printf ("Stepping out of function \"%s\" because it matches the avoid regexp \"%s\" - match substring: \"%s\".",
                                     frame_function_name,
                                     avoid_regexp_to_use->GetText(),
                                     match.c_str());
                    }

                }
                return return_value;
            }
        }
    }
    return false;
}

bool
ThreadPlanStepInRange::DefaultShouldStopHereCallback (ThreadPlan *current_plan, Flags &flags, FrameComparison operation, void *baton)
{
    bool should_stop_here = true;
    StackFrame *frame = current_plan->GetThread().GetStackFrameAtIndex(0).get();
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));

    // First see if the ThreadPlanShouldStopHere default implementation thinks we should get out of here:
    should_stop_here = ThreadPlanShouldStopHere::DefaultShouldStopHereCallback (current_plan, flags, operation, baton);
    if (!should_stop_here)
        return should_stop_here;
    
    if (should_stop_here && current_plan->GetKind() == eKindStepInRange && operation == eFrameCompareYounger)
    {
        ThreadPlanStepInRange *step_in_range_plan = static_cast<ThreadPlanStepInRange *> (current_plan);
        if (step_in_range_plan->m_step_into_target)
        {
            SymbolContext sc = frame->GetSymbolContext(eSymbolContextFunction|eSymbolContextBlock|eSymbolContextSymbol);
            if (sc.symbol != nullptr)
            {
                // First try an exact match, since that's cheap with ConstStrings.  Then do a strstr compare.
                if (step_in_range_plan->m_step_into_target == sc.GetFunctionName())
                {
                    should_stop_here = true;
                }
                else
                {
                    const char *target_name = step_in_range_plan->m_step_into_target.AsCString();
                    const char *function_name = sc.GetFunctionName().AsCString();
                    
                    if (function_name == nullptr)
                        should_stop_here = false;
                    else if (strstr(function_name, target_name) == nullptr)
                        should_stop_here = false;
                }
                if (log && !should_stop_here)
                    log->Printf("Stepping out of frame %s which did not match step into target %s.",
                                sc.GetFunctionName().AsCString(),
                                step_in_range_plan->m_step_into_target.AsCString());
            }
        }
        
        if (should_stop_here)
        {
            ThreadPlanStepInRange *step_in_range_plan = static_cast<ThreadPlanStepInRange *> (current_plan);
            // Don't log the should_step_out here, it's easier to do it in FrameMatchesAvoidCriteria.
            should_stop_here = !step_in_range_plan->FrameMatchesAvoidCriteria ();
        }
    }
    
    return should_stop_here;
}

bool
ThreadPlanStepInRange::DoPlanExplainsStop (Event *event_ptr)
{
    // We always explain a stop.  Either we've just done a single step, in which
    // case we'll do our ordinary processing, or we stopped for some
    // reason that isn't handled by our sub-plans, in which case we want to just stop right
    // away.
    // In general, we don't want to mark the plan as complete for unexplained stops.
    // For instance, if you step in to some code with no debug info, so you step out
    // and in the course of that hit a breakpoint, then you want to stop & show the user
    // the breakpoint, but not unship the step in plan, since you still may want to complete that
    // plan when you continue.  This is particularly true when doing "step in to target function."
    // stepping.
    //
    // The only variation is that if we are doing "step by running to next branch" in which case
    // if we hit our branch breakpoint we don't set the plan to complete.
            
    bool return_value = false;
    
    if (m_virtual_step)
    {
        return_value = true;
    }
    else
    {
        StopInfoSP stop_info_sp = GetPrivateStopInfo ();
        if (stop_info_sp)
        {
            StopReason reason = stop_info_sp->GetStopReason();
            
            if (reason ==  eStopReasonBreakpoint)
            {
                if (NextRangeBreakpointExplainsStop(stop_info_sp))
                {
                    return_value = true;
                }
            }
            else if (IsUsuallyUnexplainedStopReason(reason))
            {
                Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
                if (log)
                    log->PutCString ("ThreadPlanStepInRange got asked if it explains the stop for some reason other than step.");
                return_value = false;
            }
            else
            {
                return_value = true;
            }
        }
        else
            return_value = true;
    }
    
    return return_value;
}

bool
ThreadPlanStepInRange::DoWillResume (lldb::StateType resume_state, bool current_plan)
{
    m_virtual_step = false;
    if (resume_state == eStateStepping && current_plan)
    {
        // See if we are about to step over a virtual inlined call.
        bool step_without_resume = m_thread.DecrementCurrentInlinedDepth();
        if (step_without_resume)
        {
            Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
            if (log)
                log->Printf ("ThreadPlanStepInRange::DoWillResume: returning false, inline_depth: %d",
                             m_thread.GetCurrentInlinedDepth());
            SetStopInfo(StopInfo::CreateStopReasonToTrace(m_thread));
            
            // FIXME: Maybe it would be better to create a InlineStep stop reason, but then
            // the whole rest of the world would have to handle that stop reason.
            m_virtual_step = true;
        }
        return !step_without_resume;
    }
    return true;
}

bool
ThreadPlanStepInRange::IsVirtualStep()
{
    return m_virtual_step;
}