lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp

//===-- DynamicLoaderDarwin.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/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Core/DataBuffer.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Section.h"
#include "lldb/Core/State.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/ObjCLanguageRuntime.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Target/ThreadPlanRunToAddress.h"

#include "DynamicLoaderDarwin.h"

//#define ENABLE_DEBUG_PRINTF // COMMENT THIS LINE OUT PRIOR TO CHECKIN
#ifdef ENABLE_DEBUG_PRINTF
#include <stdio.h>
#define DEBUG_PRINTF(fmt, ...) printf(fmt, ## __VA_ARGS__)
#else
#define DEBUG_PRINTF(fmt, ...)
#endif

#ifndef __APPLE__
#include "Utility/UuidCompatibility.h"
#else
#include <uuid/uuid.h>
#endif

using namespace lldb;
using namespace lldb_private;


//----------------------------------------------------------------------
// Constructor
//----------------------------------------------------------------------
DynamicLoaderDarwin::DynamicLoaderDarwin (Process* process) 
    : DynamicLoader(process),
      m_dyld_module_wp(),
      m_libpthread_module_wp(),
      m_pthread_getspecific_addr(),
      m_tid_to_tls_map(),
      m_dyld_image_infos(),
      m_dyld_image_infos_stop_id(UINT32_MAX),
      m_dyld(),
      m_mutex()
{
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
DynamicLoaderDarwin::~DynamicLoaderDarwin()
{
}

//------------------------------------------------------------------
/// Called after attaching a process.
///
/// Allow DynamicLoader plug-ins to execute some code after
/// attaching to a process.
//------------------------------------------------------------------
void
DynamicLoaderDarwin::DidAttach ()
{
    PrivateInitialize(m_process);
    DoInitialImageFetch ();
    SetNotificationBreakpoint ();
}

//------------------------------------------------------------------
/// Called after attaching a process.
///
/// Allow DynamicLoader plug-ins to execute some code after
/// attaching to a process.
//------------------------------------------------------------------
void
DynamicLoaderDarwin::DidLaunch ()
{
    PrivateInitialize(m_process);
    DoInitialImageFetch ();
    SetNotificationBreakpoint ();
}


//----------------------------------------------------------------------
// Clear out the state of this class.
//----------------------------------------------------------------------
void
DynamicLoaderDarwin::Clear (bool clear_process)
{
    std::lock_guard<std::recursive_mutex> guard(m_mutex);
    if (clear_process)
        m_process = NULL;
    m_dyld_image_infos.clear();
    m_dyld_image_infos_stop_id = UINT32_MAX;
    m_dyld.Clear(false);
}

ModuleSP
DynamicLoaderDarwin::FindTargetModuleForImageInfo (ImageInfo &image_info, bool can_create, bool *did_create_ptr)
{
    if (did_create_ptr)
        *did_create_ptr = false;
    
    Target &target = m_process->GetTarget();
    const ModuleList &target_images = target.GetImages();
    ModuleSpec module_spec (image_info.file_spec);
    module_spec.GetUUID() = image_info.uuid;
    ModuleSP module_sp (target_images.FindFirstModule (module_spec));
    
    if (module_sp && !module_spec.GetUUID().IsValid() && !module_sp->GetUUID().IsValid())
    {
        // No UUID, we must rely upon the cached module modification 
        // time and the modification time of the file on disk
        if (module_sp->GetModificationTime() != module_sp->GetFileSpec().GetModificationTime())
            module_sp.reset();
    }

    if (!module_sp)
    {
        if (can_create)
        {
            module_sp = target.GetSharedModule (module_spec);
            if (!module_sp || module_sp->GetObjectFile() == NULL)
                module_sp = m_process->ReadModuleFromMemory (image_info.file_spec, image_info.address);

            if (did_create_ptr)
                *did_create_ptr = (bool) module_sp;
        }
    }
    return module_sp;
}

void
DynamicLoaderDarwin::UnloadImages (const std::vector<lldb::addr_t> &solib_addresses)
{
    std::lock_guard<std::recursive_mutex> guard(m_mutex);
    if (m_process->GetStopID() == m_dyld_image_infos_stop_id)
        return;

    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    Target &target = m_process->GetTarget();
    if (log)
        log->Printf ("Removing %" PRId64 " modules.", (uint64_t) solib_addresses.size());

    ModuleList unloaded_module_list;

    for (addr_t solib_addr : solib_addresses)
    {
        Address header;
        if (header.SetLoadAddress (solib_addr, &target))
        {
            if (header.GetOffset() == 0)
            {
                ModuleSP module_to_remove (header.GetModule());
                if (module_to_remove.get())
                {
                    if (log)
                        log->Printf ("Removing module at address 0x%" PRIx64, solib_addr);
                    // remove the sections from the Target
                    UnloadSections (module_to_remove);
                    // add this to the list of modules to remove
                    unloaded_module_list.AppendIfNeeded (module_to_remove);
                    // remove the entry from the m_dyld_image_infos
                    ImageInfo::collection::iterator pos, end = m_dyld_image_infos.end();
                    for (pos = m_dyld_image_infos.begin(); pos != end; pos++)
                    {
                        if (solib_addr == (*pos).address)
                        {
                            m_dyld_image_infos.erase(pos);
                            break;
                        }
                    }
                }
            }
        }
    }

    if (unloaded_module_list.GetSize() > 0)
    {
        if (log)
        {
            log->PutCString("Unloaded:");
            unloaded_module_list.LogUUIDAndPaths (log, "DynamicLoaderDarwin::UnloadModules");
        }
        m_process->GetTarget().GetImages().Remove (unloaded_module_list);
        m_dyld_image_infos_stop_id = m_process->GetStopID();
    }
}

void
DynamicLoaderDarwin::UnloadAllImages ()
{
    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    ModuleList unloaded_modules_list;

    Target &target = m_process->GetTarget();
    const ModuleList &target_modules = target.GetImages();
    std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());

    size_t num_modules = target_modules.GetSize();
    ModuleSP dyld_sp (GetDYLDModule());

    for (size_t i = 0; i < num_modules; i++)
    {
        ModuleSP module_sp = target_modules.GetModuleAtIndexUnlocked (i);

        // Don't remove dyld - else we'll lose our breakpoint notifying us about libraries
        // being re-loaded...
        if (module_sp.get() != nullptr
            && module_sp.get() != dyld_sp.get())
        {
            UnloadSections (module_sp);
            unloaded_modules_list.Append (module_sp);
        }
    }

    if (unloaded_modules_list.GetSize() != 0)
    {
        if (log)
        {
            log->PutCString("Unloaded:");
            unloaded_modules_list.LogUUIDAndPaths (log, "DynamicLoaderDarwin::UnloadAllImages");
        }
        target.GetImages().Remove(unloaded_modules_list);
        m_dyld_image_infos.clear();
        m_dyld_image_infos_stop_id = m_process->GetStopID();
    }
}

//----------------------------------------------------------------------
// Update the load addresses for all segments in MODULE using the
// updated INFO that is passed in.
//----------------------------------------------------------------------
bool
DynamicLoaderDarwin::UpdateImageLoadAddress (Module *module, ImageInfo& info)
{
    bool changed = false;
    if (module)
    {
        ObjectFile *image_object_file = module->GetObjectFile();
        if (image_object_file)
        {
            SectionList *section_list = image_object_file->GetSectionList ();
            if (section_list)
            {
                std::vector<uint32_t> inaccessible_segment_indexes;
                // We now know the slide amount, so go through all sections
                // and update the load addresses with the correct values.
                const size_t num_segments = info.segments.size();
                for (size_t i=0; i<num_segments; ++i)
                {
                    // Only load a segment if it has protections. Things like
                    // __PAGEZERO don't have any protections, and they shouldn't
                    // be slid
                    SectionSP section_sp(section_list->FindSectionByName(info.segments[i].name));

                    if (info.segments[i].maxprot == 0)
                    {
                        inaccessible_segment_indexes.push_back(i);
                    }
                    else
                    {
                        const addr_t new_section_load_addr = info.segments[i].vmaddr + info.slide;
                        static ConstString g_section_name_LINKEDIT ("__LINKEDIT");

                        if (section_sp)
                        {
                            // __LINKEDIT sections from files in the shared cache
                            // can overlap so check to see what the segment name is
                            // and pass "false" so we don't warn of overlapping
                            // "Section" objects, and "true" for all other sections.
                            const bool warn_multiple = section_sp->GetName() != g_section_name_LINKEDIT;

                            changed = m_process->GetTarget().SetSectionLoadAddress (section_sp, new_section_load_addr, warn_multiple);
                        }
                        else
                        {
                            Host::SystemLog (Host::eSystemLogWarning, 
                                             "warning: unable to find and load segment named '%s' at 0x%" PRIx64 " in '%s' in macosx dynamic loader plug-in.\n",
                                             info.segments[i].name.AsCString("<invalid>"),
                                             (uint64_t)new_section_load_addr,
                                             image_object_file->GetFileSpec().GetPath().c_str());
                        }
                    }
                }
                
                // If the loaded the file (it changed) and we have segments that
                // are not readable or writeable, add them to the invalid memory
                // region cache for the process. This will typically only be
                // the __PAGEZERO segment in the main executable. We might be able
                // to apply this more generally to more sections that have no
                // protections in the future, but for now we are going to just
                // do __PAGEZERO.
                if (changed && !inaccessible_segment_indexes.empty())
                {
                    for (uint32_t i=0; i<inaccessible_segment_indexes.size(); ++i)
                    {
                        const uint32_t seg_idx = inaccessible_segment_indexes[i];
                        SectionSP section_sp(section_list->FindSectionByName(info.segments[seg_idx].name));

                        if (section_sp)
                        {
                            static ConstString g_pagezero_section_name("__PAGEZERO");
                            if (g_pagezero_section_name == section_sp->GetName())
                            {
                                // __PAGEZERO never slides...
                                const lldb::addr_t vmaddr = info.segments[seg_idx].vmaddr;
                                const lldb::addr_t vmsize = info.segments[seg_idx].vmsize;
                                Process::LoadRange pagezero_range (vmaddr, vmsize);
                                m_process->AddInvalidMemoryRegion(pagezero_range);
                            }
                        }
                    }
                }
            }
        }
    }
    // We might have an in memory image that was loaded as soon as it was created
    if (info.load_stop_id == m_process->GetStopID())
        changed = true;
    else if (changed)
    {
        // Update the stop ID when this library was updated
        info.load_stop_id = m_process->GetStopID();
    }
    return changed;
}

//----------------------------------------------------------------------
// Unload the segments in MODULE using the INFO that is passed in.
//----------------------------------------------------------------------
bool
DynamicLoaderDarwin::UnloadModuleSections (Module *module, ImageInfo& info)
{
    bool changed = false;
    if (module)
    {
        ObjectFile *image_object_file = module->GetObjectFile();
        if (image_object_file)
        {
            SectionList *section_list = image_object_file->GetSectionList ();
            if (section_list)
            {
                const size_t num_segments = info.segments.size();
                for (size_t i=0; i<num_segments; ++i)
                {
                    SectionSP section_sp(section_list->FindSectionByName(info.segments[i].name));
                    if (section_sp)
                    {
                        const addr_t old_section_load_addr = info.segments[i].vmaddr + info.slide;
                        if (m_process->GetTarget().SetSectionUnloaded (section_sp, old_section_load_addr))
                            changed = true;
                    }
                    else
                    {
                        Host::SystemLog (Host::eSystemLogWarning, 
                                         "warning: unable to find and unload segment named '%s' in '%s' in macosx dynamic loader plug-in.\n",
                                         info.segments[i].name.AsCString("<invalid>"),
                                         image_object_file->GetFileSpec().GetPath().c_str());
                    }
                }
            }
        }
    }
    return changed;
}


// Given a JSON dictionary (from debugserver, most likely) of binary images loaded in the inferior
// process, add the images to the ImageInfo collection.

bool
DynamicLoaderDarwin::JSONImageInformationIntoImageInfo (StructuredData::ObjectSP image_details, ImageInfo::collection &image_infos)
{
    StructuredData::ObjectSP images_sp = image_details->GetAsDictionary()->GetValueForKey("images");
    if (images_sp.get() == nullptr)
        return false;

    image_infos.resize (images_sp->GetAsArray()->GetSize());

    for (size_t i = 0; i < image_infos.size(); i++)
    {
        StructuredData::ObjectSP image_sp = images_sp->GetAsArray()->GetItemAtIndex(i);
        if (image_sp.get() == nullptr || image_sp->GetAsDictionary() == nullptr)
            return false;
        StructuredData::Dictionary *image = image_sp->GetAsDictionary();
        if (image->HasKey("load_address") == false 
            || image->HasKey("pathname") == false 
            || image->HasKey("mod_date") == false
            || image->HasKey("mach_header") == false 
            || image->GetValueForKey("mach_header")->GetAsDictionary() == nullptr
            || image->HasKey("segments") == false 
            || image->GetValueForKey("segments")->GetAsArray() == nullptr
            || image->HasKey("uuid") == false )
        {
            return false;
        }
        image_infos[i].address = image->GetValueForKey("load_address")->GetAsInteger()->GetValue();
        image_infos[i].mod_date = image->GetValueForKey("mod_date")->GetAsInteger()->GetValue();
        image_infos[i].file_spec.SetFile(image->GetValueForKey("pathname")->GetAsString()->GetValue().c_str(), false);

        StructuredData::Dictionary *mh = image->GetValueForKey("mach_header")->GetAsDictionary();
        image_infos[i].header.magic = mh->GetValueForKey("magic")->GetAsInteger()->GetValue();
        image_infos[i].header.cputype = mh->GetValueForKey("cputype")->GetAsInteger()->GetValue();
        image_infos[i].header.cpusubtype = mh->GetValueForKey("cpusubtype")->GetAsInteger()->GetValue();
        image_infos[i].header.filetype = mh->GetValueForKey("filetype")->GetAsInteger()->GetValue();

        if (image->HasKey("min_version_os_name"))
        {
            std::string os_name = image->GetValueForKey("min_version_os_name")->GetAsString()->GetValue();
            if (os_name == "macosx")
                image_infos[i].os_type = llvm::Triple::MacOSX;
            else if (os_name == "ios" || os_name == "iphoneos")
                image_infos[i].os_type = llvm::Triple::IOS;
            else if (os_name == "tvos")
                image_infos[i].os_type = llvm::Triple::TvOS;
            else if (os_name == "watchos")
                image_infos[i].os_type = llvm::Triple::WatchOS;
        }
        if (image->HasKey("min_version_os_sdk"))
        {
            image_infos[i].min_version_os_sdk = image->GetValueForKey("min_version_os_sdk")->GetAsString()->GetValue();
        }

        // Fields that aren't used by DynamicLoaderDarwin so debugserver doesn't currently send them
        // in the reply.

        if (mh->HasKey("flags"))
            image_infos[i].header.flags = mh->GetValueForKey("flags")->GetAsInteger()->GetValue();
        else
            image_infos[i].header.flags = 0;

        if (mh->HasKey("ncmds"))
            image_infos[i].header.ncmds = mh->GetValueForKey("ncmds")->GetAsInteger()->GetValue();
        else
            image_infos[i].header.ncmds = 0;

        if (mh->HasKey("sizeofcmds"))
            image_infos[i].header.sizeofcmds = mh->GetValueForKey("sizeofcmds")->GetAsInteger()->GetValue();
        else
            image_infos[i].header.sizeofcmds = 0;

        StructuredData::Array *segments = image->GetValueForKey("segments")->GetAsArray();
        uint32_t segcount = segments->GetSize();
        for (size_t j = 0; j < segcount; j++)
        {
            Segment segment;
            StructuredData::Dictionary *seg = segments->GetItemAtIndex(j)->GetAsDictionary();
            segment.name = ConstString(seg->GetValueForKey("name")->GetAsString()->GetValue().c_str());
            segment.vmaddr = seg->GetValueForKey("vmaddr")->GetAsInteger()->GetValue();
            segment.vmsize = seg->GetValueForKey("vmsize")->GetAsInteger()->GetValue();
            segment.fileoff = seg->GetValueForKey("fileoff")->GetAsInteger()->GetValue();
            segment.filesize = seg->GetValueForKey("filesize")->GetAsInteger()->GetValue();
            segment.maxprot = seg->GetValueForKey("maxprot")->GetAsInteger()->GetValue();

            // Fields that aren't used by DynamicLoaderDarwin so debugserver doesn't currently send them
            // in the reply.

            if (seg->HasKey("initprot"))
                segment.initprot = seg->GetValueForKey("initprot")->GetAsInteger()->GetValue();
            else
                segment.initprot = 0;

            if (seg->HasKey("flags"))
                segment.flags = seg->GetValueForKey("flags")->GetAsInteger()->GetValue();
            else
                segment.flags = 0;

            if (seg->HasKey("nsects"))
                segment.nsects = seg->GetValueForKey("nsects")->GetAsInteger()->GetValue();
            else
                segment.nsects = 0;

            image_infos[i].segments.push_back (segment);
        }

        image_infos[i].uuid.SetFromCString (image->GetValueForKey("uuid")->GetAsString()->GetValue().c_str());

        // All sections listed in the dyld image info structure will all
        // either be fixed up already, or they will all be off by a single
        // slide amount that is determined by finding the first segment
        // that is at file offset zero which also has bytes (a file size
        // that is greater than zero) in the object file.
    
        // Determine the slide amount (if any)
        const size_t num_sections = image_infos[i].segments.size();
        for (size_t k = 0; k < num_sections; ++k)
        {
            // Iterate through the object file sections to find the
            // first section that starts of file offset zero and that
            // has bytes in the file...
            if ((image_infos[i].segments[k].fileoff == 0 && image_infos[i].segments[k].filesize > 0) 
                || (image_infos[i].segments[k].name == ConstString("__TEXT")))
            {
                image_infos[i].slide = image_infos[i].address - image_infos[i].segments[k].vmaddr;
                // We have found the slide amount, so we can exit
                // this for loop.
                break;
            }
        }
    }

 return true;
}

void
DynamicLoaderDarwin::UpdateSpecialBinariesFromNewImageInfos (ImageInfo::collection &image_infos)
{
    uint32_t exe_idx = UINT32_MAX;
    uint32_t dyld_idx = UINT32_MAX;
    Target &target = m_process->GetTarget();
    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    ConstString g_dyld_sim_filename ("dyld_sim");

    ArchSpec target_arch = target.GetArchitecture();
    const size_t image_infos_size = image_infos.size();
    for (size_t i = 0; i < image_infos_size; i++)
    {
        if (image_infos[i].header.filetype == llvm::MachO::MH_DYLINKER)
        {
            // In a "simulator" process (an x86 process that is ios/tvos/watchos)
            // we will have two dyld modules -- a "dyld" that we want to keep track of,
            // and a "dyld_sim" which we don't need to keep track of here.  
            // If the target is an x86 system and the OS of the dyld binary is 
            // ios/tvos/watchos, then we are looking at dyld_sym.

            // debugserver has only recently (late 2016) started sending up the
            // os type for each binary it sees -- so if we don't have an os
            // type, use a filename check as our next best guess.
            if (image_infos[i].os_type == llvm::Triple::OSType::UnknownOS)
            {
                if (image_infos[i].file_spec.GetFilename() != g_dyld_sim_filename)
                {
                    dyld_idx = i;
                }
            }
            else if (target_arch.GetTriple().getArch() == llvm::Triple::x86 
                     || target_arch.GetTriple().getArch() == llvm::Triple::x86_64)
            {
                if (image_infos[i].os_type != llvm::Triple::OSType::IOS
                    && image_infos[i].os_type != llvm::Triple::TvOS
                    && image_infos[i].os_type != llvm::Triple::WatchOS)
                {
                    dyld_idx = i;
                }
            }
        }
        else if (image_infos[i].header.filetype == llvm::MachO::MH_EXECUTE)
        {
            exe_idx = i;
        }
    }

    if (exe_idx != UINT32_MAX)
    {
        const bool can_create = true;
        ModuleSP exe_module_sp (FindTargetModuleForImageInfo (image_infos[exe_idx], can_create, NULL));
        if (exe_module_sp)
        {
            if (log)
                log->Printf ("Found executable module: %s", exe_module_sp->GetFileSpec().GetPath().c_str());
            target.GetImages().AppendIfNeeded (exe_module_sp);
            UpdateImageLoadAddress (exe_module_sp.get(), image_infos[exe_idx]);
            if (exe_module_sp.get() != target.GetExecutableModulePointer())
            {
                const bool get_dependent_images = false;
                target.SetExecutableModule (exe_module_sp, get_dependent_images);
            }
        }
    }

    if (dyld_idx != UINT32_MAX)
    {
        const bool can_create = true;
        ModuleSP dyld_sp = FindTargetModuleForImageInfo (image_infos[dyld_idx], can_create, NULL);
        if (dyld_sp.get())
        {
            if (log)
                log->Printf ("Found dyld module: %s", dyld_sp->GetFileSpec().GetPath().c_str());
            target.GetImages().AppendIfNeeded (dyld_sp);
            UpdateImageLoadAddress (dyld_sp.get(), image_infos[dyld_idx]);
            SetDYLDModule (dyld_sp);
        }
    }
}

void
DynamicLoaderDarwin::UpdateDYLDImageInfoFromNewImageInfo (ImageInfo &image_info)
{
    if (image_info.header.filetype == llvm::MachO::MH_DYLINKER)
    {
        const bool can_create = true;
        ModuleSP dyld_sp = FindTargetModuleForImageInfo (image_info, can_create, NULL);
        if (dyld_sp.get())
        {
            Target &target = m_process->GetTarget();
            target.GetImages().AppendIfNeeded (dyld_sp);
            UpdateImageLoadAddress (dyld_sp.get(), image_info);
            SetDYLDModule (dyld_sp);
        }
    }
}

void
DynamicLoaderDarwin::SetDYLDModule (lldb::ModuleSP &dyld_module_sp)
{
    m_dyld_module_wp = dyld_module_sp;
}

ModuleSP
DynamicLoaderDarwin::GetDYLDModule ()
{
    ModuleSP dyld_sp (m_dyld_module_wp.lock());
    return dyld_sp;
}

bool
DynamicLoaderDarwin::AddModulesUsingImageInfos (ImageInfo::collection &image_infos)
{
    std::lock_guard<std::recursive_mutex> guard(m_mutex);
    // Now add these images to the main list.
    ModuleList loaded_module_list;
    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    Target &target = m_process->GetTarget();
    ModuleList& target_images = target.GetImages();
    
    for (uint32_t idx = 0; idx < image_infos.size(); ++idx)
    {
        if (log)
        {
            log->Printf ("Adding new image at address=0x%16.16" PRIx64 ".", image_infos[idx].address);
            image_infos[idx].PutToLog (log);
        }
        
        m_dyld_image_infos.push_back(image_infos[idx]);
        
        ModuleSP image_module_sp (FindTargetModuleForImageInfo (image_infos[idx], true, NULL));

        if (image_module_sp)
        {
            ObjectFile *objfile = image_module_sp->GetObjectFile ();
            if (objfile)
            {
                SectionList *sections = objfile->GetSectionList();
                if (sections)
                {
                    ConstString commpage_dbstr("__commpage");
                    Section *commpage_section = sections->FindSectionByName(commpage_dbstr).get();
                    if (commpage_section)
                    {
                        ModuleSpec module_spec (objfile->GetFileSpec(), image_infos[idx].GetArchitecture ());
                        module_spec.GetObjectName() = commpage_dbstr;
                        ModuleSP commpage_image_module_sp(target_images.FindFirstModule (module_spec));
                        if (!commpage_image_module_sp)
                        {
                            module_spec.SetObjectOffset (objfile->GetFileOffset() + commpage_section->GetFileOffset());
                            module_spec.SetObjectSize (objfile->GetByteSize());
                            commpage_image_module_sp  = target.GetSharedModule (module_spec);
                            if (!commpage_image_module_sp || commpage_image_module_sp->GetObjectFile() == NULL)
                            {
                                commpage_image_module_sp = m_process->ReadModuleFromMemory (image_infos[idx].file_spec,
                                                                                            image_infos[idx].address);
                                // Always load a memory image right away in the target in case
                                // we end up trying to read the symbol table from memory... The
                                // __LINKEDIT will need to be mapped so we can figure out where
                                // the symbol table bits are...
                                bool changed = false;
                                UpdateImageLoadAddress (commpage_image_module_sp.get(), image_infos[idx]);
                                target.GetImages().Append(commpage_image_module_sp);
                                if (changed)
                                {
                                    image_infos[idx].load_stop_id = m_process->GetStopID();
                                    loaded_module_list.AppendIfNeeded (commpage_image_module_sp);
                                }
                            }
                        }
                    }
                }
            }

            // UpdateImageLoadAddress will return true if any segments
            // change load address. We need to check this so we don't
            // mention that all loaded shared libraries are newly loaded
            // each time we hit out dyld breakpoint since dyld will list all
            // shared libraries each time.
            if (UpdateImageLoadAddress (image_module_sp.get(), image_infos[idx]))
            {
                target_images.AppendIfNeeded(image_module_sp);
                loaded_module_list.AppendIfNeeded (image_module_sp);
            }
        }
    }
    
    if (loaded_module_list.GetSize() > 0)
    {
        if (log)
            loaded_module_list.LogUUIDAndPaths (log, "DynamicLoaderDarwin::ModulesDidLoad");
        m_process->GetTarget().ModulesDidLoad (loaded_module_list);
    }
    return true;
}


//----------------------------------------------------------------------
// On Mac OS X libobjc (the Objective-C runtime) has several critical dispatch
// functions written in hand-written assembly, and also have hand-written unwind
// information in the eh_frame section.  Normally we prefer analyzing the 
// assembly instructions of a currently executing frame to unwind from that frame --
// but on hand-written functions this profiling can fail.  We should use the
// eh_frame instructions for these functions all the time.
//
// As an aside, it would be better if the eh_frame entries had a flag (or were
// extensible so they could have an Apple-specific flag) which indicates that
// the instructions are asynchronous -- accurate at every instruction, instead
// of our normal default assumption that they are not.
//----------------------------------------------------------------------

bool
DynamicLoaderDarwin::AlwaysRelyOnEHUnwindInfo (SymbolContext &sym_ctx)
{
    ModuleSP module_sp;
    if (sym_ctx.symbol)
    {
        module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
    }
    if (module_sp.get() == NULL && sym_ctx.function)
    {
        module_sp = sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
    }
    if (module_sp.get() == NULL)
        return false;

    ObjCLanguageRuntime *objc_runtime = m_process->GetObjCLanguageRuntime();
    if (objc_runtime != NULL && objc_runtime->IsModuleObjCLibrary (module_sp))
    {
        return true;
    }

    return false;
}



//----------------------------------------------------------------------
// Dump a Segment to the file handle provided.
//----------------------------------------------------------------------
void
DynamicLoaderDarwin::Segment::PutToLog (Log *log, lldb::addr_t slide) const
{
    if (log)
    {
        if (slide == 0)
            log->Printf ("\t\t%16s [0x%16.16" PRIx64 " - 0x%16.16" PRIx64 ")",
                         name.AsCString(""), 
                         vmaddr + slide, 
                         vmaddr + slide + vmsize);
        else
            log->Printf ("\t\t%16s [0x%16.16" PRIx64 " - 0x%16.16" PRIx64 ") slide = 0x%" PRIx64,
                         name.AsCString(""), 
                         vmaddr + slide, 
                         vmaddr + slide + vmsize, 
                         slide);
    }
}

const DynamicLoaderDarwin::Segment *
DynamicLoaderDarwin::ImageInfo::FindSegment (const ConstString &name) const
{
    const size_t num_segments = segments.size();
    for (size_t i=0; i<num_segments; ++i)
    {
        if (segments[i].name == name)
            return &segments[i];
    }
    return NULL;
}


//----------------------------------------------------------------------
// Dump an image info structure to the file handle provided.
//----------------------------------------------------------------------
void
DynamicLoaderDarwin::ImageInfo::PutToLog (Log *log) const
{
    if (log == NULL)
        return;
    const uint8_t *u = (const uint8_t *)uuid.GetBytes();

    if (address == LLDB_INVALID_ADDRESS)
    {
        if (u)
        {
            log->Printf("\t                           modtime=0x%8.8" PRIx64 " uuid=%2.2X%2.2X%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X%2.2X%2.2X%2.2X%2.2X path='%s' (UNLOADED)",
                        mod_date,
                        u[ 0], u[ 1], u[ 2], u[ 3],
                        u[ 4], u[ 5], u[ 6], u[ 7],
                        u[ 8], u[ 9], u[10], u[11],
                        u[12], u[13], u[14], u[15],
                        file_spec.GetPath().c_str());
        }
        else
            log->Printf("\t                           modtime=0x%8.8" PRIx64 " path='%s' (UNLOADED)",
                        mod_date,
                        file_spec.GetPath().c_str());
    }
    else
    {
        if (u)
        {
            log->Printf("\taddress=0x%16.16" PRIx64 " modtime=0x%8.8" PRIx64 " uuid=%2.2X%2.2X%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X%2.2X%2.2X%2.2X%2.2X path='%s'",
                        address,
                        mod_date,
                        u[ 0], u[ 1], u[ 2], u[ 3],
                        u[ 4], u[ 5], u[ 6], u[ 7],
                        u[ 8], u[ 9], u[10], u[11],
                        u[12], u[13], u[14], u[15],
                        file_spec.GetPath().c_str());
        }
        else
        {
            log->Printf("\taddress=0x%16.16" PRIx64 " modtime=0x%8.8" PRIx64 " path='%s'",
                        address,
                        mod_date,
                        file_spec.GetPath().c_str());

        }
        for (uint32_t i=0; i<segments.size(); ++i)
            segments[i].PutToLog(log, slide);
    }
}

void
DynamicLoaderDarwin::PrivateInitialize(Process *process)
{
    DEBUG_PRINTF("DynamicLoaderDarwin::%s() process state = %s\n", __FUNCTION__, StateAsCString(m_process->GetState()));
    Clear(true);
    m_process = process;
    m_process->GetTarget().ClearAllLoadedSections();
}

//----------------------------------------------------------------------
// Member function that gets called when the process state changes.
//----------------------------------------------------------------------
void
DynamicLoaderDarwin::PrivateProcessStateChanged (Process *process, StateType state)
{
    DEBUG_PRINTF("DynamicLoaderDarwin::%s(%s)\n", __FUNCTION__, StateAsCString(state));
    switch (state)
    {
    case eStateConnected:
    case eStateAttaching:
    case eStateLaunching:
    case eStateInvalid:
    case eStateUnloaded:
    case eStateExited:
    case eStateDetached:
        Clear(false);
        break;

    case eStateStopped:
        // Keep trying find dyld and set our notification breakpoint each time
        // we stop until we succeed
        if (!DidSetNotificationBreakpoint () && m_process->IsAlive())
        {
            if (NeedToDoInitialImageFetch ())
                DoInitialImageFetch ();

            SetNotificationBreakpoint ();
        }
        break;

    case eStateRunning:
    case eStateStepping:
    case eStateCrashed:
    case eStateSuspended:
        break;
    }
}

ThreadPlanSP
DynamicLoaderDarwin::GetStepThroughTrampolinePlan (Thread &thread, bool stop_others)
{
    ThreadPlanSP thread_plan_sp;
    StackFrame *current_frame = thread.GetStackFrameAtIndex(0).get();
    const SymbolContext &current_context = current_frame->GetSymbolContext(eSymbolContextSymbol);
    Symbol *current_symbol = current_context.symbol;
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
    TargetSP target_sp (thread.CalculateTarget());

    if (current_symbol != NULL)
    {
        std::vector<Address>  addresses;
        
        if (current_symbol->IsTrampoline())
        {
            const ConstString &trampoline_name = current_symbol->GetMangled().GetName(current_symbol->GetLanguage(), Mangled::ePreferMangled);
            
            if (trampoline_name)
            {
                const ModuleList &images = target_sp->GetImages();
                
                SymbolContextList code_symbols;
                images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeCode, code_symbols);
                size_t num_code_symbols = code_symbols.GetSize();
                
                if (num_code_symbols > 0)
                {
                    for (uint32_t i = 0; i < num_code_symbols; i++)
                    {
                        SymbolContext context;
                        AddressRange addr_range;
                        if (code_symbols.GetContextAtIndex(i, context))
                        {
                            context.GetAddressRange (eSymbolContextEverything, 0, false, addr_range);
                            addresses.push_back(addr_range.GetBaseAddress());
                            if (log)
                            {
                                addr_t load_addr = addr_range.GetBaseAddress().GetLoadAddress(target_sp.get());

                                log->Printf ("Found a trampoline target symbol at 0x%" PRIx64 ".", load_addr);
                            }
                        }
                    }
                }
                
                SymbolContextList reexported_symbols;
                images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeReExported, reexported_symbols);
                size_t num_reexported_symbols = reexported_symbols.GetSize();
                if (num_reexported_symbols > 0)
                {
                    for (uint32_t i = 0; i < num_reexported_symbols; i++)
                    {
                        SymbolContext context;
                        if (reexported_symbols.GetContextAtIndex(i, context))
                        {
                            if (context.symbol)
                            {
                                Symbol *actual_symbol = context.symbol->ResolveReExportedSymbol(*target_sp.get());
                                if (actual_symbol)
                                {
                                    const Address actual_symbol_addr = actual_symbol->GetAddress();
                                    if (actual_symbol_addr.IsValid())
                                    {
                                        addresses.push_back(actual_symbol_addr);
                                        if (log)
                                        {
                                            lldb::addr_t load_addr = actual_symbol_addr.GetLoadAddress(target_sp.get());
                                            log->Printf ("Found a re-exported symbol: %s at 0x%" PRIx64 ".",
                                                         actual_symbol->GetName().GetCString(), load_addr);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                
                SymbolContextList indirect_symbols;
                images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeResolver, indirect_symbols);
                size_t num_indirect_symbols = indirect_symbols.GetSize();
                if (num_indirect_symbols > 0)
                {
                    for (uint32_t i = 0; i < num_indirect_symbols; i++)
                    {
                        SymbolContext context;
                        AddressRange addr_range;
                        if (indirect_symbols.GetContextAtIndex(i, context))
                        {
                            context.GetAddressRange (eSymbolContextEverything, 0, false, addr_range);
                            addresses.push_back(addr_range.GetBaseAddress());
                            if (log)
                            {
                                addr_t load_addr = addr_range.GetBaseAddress().GetLoadAddress(target_sp.get());

                                log->Printf ("Found an indirect target symbol at 0x%" PRIx64 ".", load_addr);
                            }
                        }
                    }
                }
            }
        }
        else if (current_symbol->GetType() == eSymbolTypeReExported)
        {
            // I am not sure we could ever end up stopped AT a re-exported symbol.  But just in case:
            
            const Symbol *actual_symbol = current_symbol->ResolveReExportedSymbol(*(target_sp.get()));
            if (actual_symbol)
            {
                Address target_addr(actual_symbol->GetAddress());
                if (target_addr.IsValid())
                {
                    if (log)
                        log->Printf ("Found a re-exported symbol: %s pointing to: %s at 0x%" PRIx64 ".",
                                     current_symbol->GetName().GetCString(),
                                     actual_symbol->GetName().GetCString(),
                                     target_addr.GetLoadAddress(target_sp.get()));
                    addresses.push_back (target_addr.GetLoadAddress(target_sp.get()));
                
                }
            }
        }
        
        if (addresses.size() > 0)
        {
            // First check whether any of the addresses point to Indirect symbols, and if they do, resolve them:
            std::vector<lldb::addr_t> load_addrs;
            for (Address address : addresses)
            {
                Symbol *symbol = address.CalculateSymbolContextSymbol();
                if (symbol && symbol->IsIndirect())
                {
                    Error error;
                    Address symbol_address = symbol->GetAddress();
                    addr_t resolved_addr = thread.GetProcess()->ResolveIndirectFunction(&symbol_address, error);
                    if (error.Success())
                    {
                        load_addrs.push_back(resolved_addr);
                        if (log)
                            log->Printf("ResolveIndirectFunction found resolved target for %s at 0x%" PRIx64 ".",
                                        symbol->GetName().GetCString(), resolved_addr);
                    }
                }
                else
                {
                    load_addrs.push_back(address.GetLoadAddress(target_sp.get()));
                }
                
            }
            thread_plan_sp.reset (new ThreadPlanRunToAddress (thread, load_addrs, stop_others));
        }
    }
    else
    {
        if (log)
            log->Printf ("Could not find symbol for step through.");
    }

    return thread_plan_sp;
}

size_t
DynamicLoaderDarwin::FindEquivalentSymbols (lldb_private::Symbol *original_symbol, 
                                               lldb_private::ModuleList &images, 
                                               lldb_private::SymbolContextList &equivalent_symbols)
{
    const ConstString &trampoline_name = original_symbol->GetMangled().GetName(original_symbol->GetLanguage(), Mangled::ePreferMangled);
    if (!trampoline_name)
        return 0;
        
    size_t initial_size = equivalent_symbols.GetSize();
    
    static const char *resolver_name_regex = "(_gc|_non_gc|\\$[A-Za-z0-9\\$]+)$";
    std::string equivalent_regex_buf("^");
    equivalent_regex_buf.append (trampoline_name.GetCString());
    equivalent_regex_buf.append (resolver_name_regex);

    RegularExpression equivalent_name_regex (equivalent_regex_buf.c_str());
    const bool append = true;
    images.FindSymbolsMatchingRegExAndType (equivalent_name_regex, eSymbolTypeCode, equivalent_symbols, append);
    
    return equivalent_symbols.GetSize() - initial_size;
}

lldb::ModuleSP
DynamicLoaderDarwin::GetPThreadLibraryModule()
{
    ModuleSP module_sp = m_libpthread_module_wp.lock();
    if (!module_sp)
    {
        SymbolContextList sc_list;
        ModuleSpec module_spec;
        module_spec.GetFileSpec().GetFilename().SetCString("libsystem_pthread.dylib");
        ModuleList module_list;
        if (m_process->GetTarget().GetImages().FindModules(module_spec, module_list))
        {
            if (module_list.GetSize() == 1)
            {
                module_sp = module_list.GetModuleAtIndex(0);
                if (module_sp)
                    m_libpthread_module_wp = module_sp;
            }
        }
    }
    return module_sp;
}

Address
DynamicLoaderDarwin::GetPthreadSetSpecificAddress()
{
    if (!m_pthread_getspecific_addr.IsValid())
    {
        ModuleSP module_sp = GetPThreadLibraryModule();
        if (module_sp)
        {
            lldb_private::SymbolContextList sc_list;
            module_sp->FindSymbolsWithNameAndType(ConstString("pthread_getspecific"), eSymbolTypeCode, sc_list);
            SymbolContext sc;
            if (sc_list.GetContextAtIndex(0, sc))
            {
                if (sc.symbol)
                    m_pthread_getspecific_addr = sc.symbol->GetAddress();
            }
        }
    }
    return m_pthread_getspecific_addr;
}

lldb::addr_t
DynamicLoaderDarwin::GetThreadLocalData(const lldb::ModuleSP module_sp, const lldb::ThreadSP thread_sp,
                                        lldb::addr_t tls_file_addr)
{
    if (!thread_sp || !module_sp)
        return LLDB_INVALID_ADDRESS;

    std::lock_guard<std::recursive_mutex> guard(m_mutex);

    const uint32_t addr_size = m_process->GetAddressByteSize();
    uint8_t buf[sizeof(lldb::addr_t) * 3];

    lldb_private::Address tls_addr;
    if (module_sp->ResolveFileAddress(tls_file_addr, tls_addr))
    {
        Error error;
        const size_t tsl_data_size = addr_size * 3;
        Target &target = m_process->GetTarget();
        if (target.ReadMemory(tls_addr, false, buf, tsl_data_size, error) == tsl_data_size)
        {
            const ByteOrder byte_order = m_process->GetByteOrder();
            DataExtractor data(buf, sizeof(buf), byte_order, addr_size);
            lldb::offset_t offset = addr_size; // Skip the first pointer
            const lldb::addr_t pthread_key = data.GetAddress(&offset);
            const lldb::addr_t tls_offset = data.GetAddress(&offset);
            if (pthread_key != 0)
            {
                // First check to see if we have already figured out the location
                // of TLS data for the pthread_key on a specific thread yet. If we
                // have we can re-use it since its location will not change unless
                // the process execs.
                const tid_t tid = thread_sp->GetID();
                auto tid_pos = m_tid_to_tls_map.find(tid);
                if (tid_pos != m_tid_to_tls_map.end())
                {
                    auto tls_pos = tid_pos->second.find(pthread_key);
                    if (tls_pos != tid_pos->second.end())
                    {
                        return tls_pos->second + tls_offset;
                    }
                }
                StackFrameSP frame_sp = thread_sp->GetStackFrameAtIndex(0);
                if (frame_sp)
                {
                    ClangASTContext *clang_ast_context = target.GetScratchClangASTContext();

                    if (!clang_ast_context)
                        return LLDB_INVALID_ADDRESS;

                    CompilerType clang_void_ptr_type = clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
                    Address pthread_getspecific_addr = GetPthreadSetSpecificAddress();
                    if (pthread_getspecific_addr.IsValid())
                    {
                        EvaluateExpressionOptions options;

                        lldb::ThreadPlanSP thread_plan_sp(
                            new ThreadPlanCallFunction(*thread_sp, pthread_getspecific_addr, clang_void_ptr_type,
                                                       llvm::ArrayRef<lldb::addr_t>(pthread_key), options));

                        DiagnosticManager execution_errors;
                        ExecutionContext exe_ctx(thread_sp);
                        lldb::ExpressionResults results =
                            m_process->RunThreadPlan(exe_ctx, thread_plan_sp, options, execution_errors);

                        if (results == lldb::eExpressionCompleted)
                        {
                            lldb::ValueObjectSP result_valobj_sp = thread_plan_sp->GetReturnValueObject();
                            if (result_valobj_sp)
                            {
                                const lldb::addr_t pthread_key_data = result_valobj_sp->GetValueAsUnsigned(0);
                                if (pthread_key_data)
                                {
                                    m_tid_to_tls_map[tid].insert(std::make_pair(pthread_key, pthread_key_data));
                                    return pthread_key_data + tls_offset;
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    return LLDB_INVALID_ADDRESS;
}

bool
DynamicLoaderDarwin::UseDYLDSPI (Process *process)
{
    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    uint32_t major, minor, update;

    bool use_new_spi_interface = false;

    if (process->GetHostOSVersion (major, minor, update))
    {
        const llvm::Triple::OSType os_type = process->GetTarget().GetArchitecture().GetTriple().getOS();

        // macOS 10.12 and newer
        if (os_type == llvm::Triple::MacOSX
            && (major >= 10 || (major == 10 && minor >= 12)))
        {
            use_new_spi_interface = true;
        }

        // iOS 10 and newer
        if (os_type == llvm::Triple::IOS && major >= 10)
        {
            use_new_spi_interface = true;
        }

        // tvOS 10 and newer
        if (os_type == llvm::Triple::TvOS && major >= 10)
        {
            use_new_spi_interface = true;
        }

        // watchOS 3 and newer
        if (os_type == llvm::Triple::WatchOS && major >= 3)
        {
            use_new_spi_interface = true;
        }
    }


    // FIXME: Temporarily force the use of the old DynamicLoader plugin until all
    // the different use cases have been tested & the updated SPIs are available 
    // everywhere.
    use_new_spi_interface = false;

    if (log)
    {
        if (use_new_spi_interface)
            log->Printf ("DynamicLoaderDarwin::UseDYLDSPI: Use new DynamicLoader plugin");
        else
            log->Printf ("DynamicLoaderDarwin::UseDYLDSPI: Use old DynamicLoader plugin");

    }
	return use_new_spi_interface;
}