xref: /llvm-project-15.0.7/lldb/source/Symbol/ObjectFile.cpp (revision 16ff8604)

//===-- ObjectFile.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/lldb-private.h"
#include "lldb/Core/DataBuffer.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/RegularExpression.h"
#include "lldb/Core/Section.h"
#include "lldb/Core/Timer.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/ObjectContainer.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Target/Process.h"
#include "Plugins/ObjectContainer/BSD-Archive/ObjectContainerBSDArchive.h"

using namespace lldb;
using namespace lldb_private;

ObjectFileSP
ObjectFile::FindPlugin (const lldb::ModuleSP &module_sp,
                        const FileSpec* file,
                        lldb::offset_t file_offset,
                        lldb::offset_t file_size,
                        DataBufferSP &data_sp,
                        lldb::offset_t &data_offset)
{
    ObjectFileSP object_file_sp;

    if (module_sp)
    {
        Timer scoped_timer (__PRETTY_FUNCTION__,
                            "ObjectFile::FindPlugin (module = %s, file = %p, file_offset = 0x%8.8" PRIx64 ", file_size = 0x%8.8" PRIx64 ")",
                            module_sp->GetFileSpec().GetPath().c_str(),
                            static_cast<const void*>(file),
                            static_cast<uint64_t>(file_offset),
                            static_cast<uint64_t>(file_size));
        if (file)
        {
            FileSpec archive_file;
            ObjectContainerCreateInstance create_object_container_callback;

            const bool file_exists = file->Exists();
            if (!data_sp)
            {
                // We have an object name which most likely means we have
                // a .o file in a static archive (.a file). Try and see if
                // we have a cached archive first without reading any data
                // first
                if (file_exists && module_sp->GetObjectName())
                {
                    for (uint32_t idx = 0; (create_object_container_callback = PluginManager::GetObjectContainerCreateCallbackAtIndex(idx)) != nullptr; ++idx)
                    {
                        std::unique_ptr<ObjectContainer> object_container_ap(create_object_container_callback(module_sp, data_sp, data_offset, file, file_offset, file_size));

                        if (object_container_ap.get())
                            object_file_sp = object_container_ap->GetObjectFile(file);

                        if (object_file_sp.get())
                            return object_file_sp;
                    }
                }
                // Ok, we didn't find any containers that have a named object, now
                // lets read the first 512 bytes from the file so the object file
                // and object container plug-ins can use these bytes to see if they
                // can parse this file.
                if (file_size > 0)
                {
                    data_sp = file->ReadFileContents(file_offset, std::min<size_t>(512, file_size));
                    data_offset = 0;
                }
            }

            if (!data_sp || data_sp->GetByteSize() == 0)
            {
                // Check for archive file with format "/path/to/archive.a(object.o)"
                char path_with_object[PATH_MAX*2];
                module_sp->GetFileSpec().GetPath(path_with_object, sizeof(path_with_object));

                ConstString archive_object;
                const bool must_exist = true;
                if (ObjectFile::SplitArchivePathWithObject (path_with_object, archive_file, archive_object, must_exist))
                {
                    file_size = archive_file.GetByteSize();
                    if (file_size > 0)
                    {
                        file = &archive_file;
                        module_sp->SetFileSpecAndObjectName (archive_file, archive_object);
                        // Check if this is a object container by iterating through all object
                        // container plugin instances and then trying to get an object file
                        // from the container plugins since we had a name. Also, don't read
                        // ANY data in case there is data cached in the container plug-ins
                        // (like BSD archives caching the contained objects within an file).
                        for (uint32_t idx = 0; (create_object_container_callback = PluginManager::GetObjectContainerCreateCallbackAtIndex(idx)) != nullptr; ++idx)
                        {
                            std::unique_ptr<ObjectContainer> object_container_ap(create_object_container_callback(module_sp, data_sp, data_offset, file, file_offset, file_size));

                            if (object_container_ap.get())
                                object_file_sp = object_container_ap->GetObjectFile(file);

                            if (object_file_sp.get())
                                return object_file_sp;
                        }
                        // We failed to find any cached object files in the container
                        // plug-ins, so lets read the first 512 bytes and try again below...
                        data_sp = archive_file.ReadFileContents(file_offset, 512);
                    }
                }
            }

            if (data_sp && data_sp->GetByteSize() > 0)
            {
                // Check if this is a normal object file by iterating through
                // all object file plugin instances.
                ObjectFileCreateInstance create_object_file_callback;
                for (uint32_t idx = 0; (create_object_file_callback = PluginManager::GetObjectFileCreateCallbackAtIndex(idx)) != nullptr; ++idx)
                {
                    object_file_sp.reset (create_object_file_callback(module_sp, data_sp, data_offset, file, file_offset, file_size));
                    if (object_file_sp.get())
                        return object_file_sp;
                }

                // Check if this is a object container by iterating through
                // all object container plugin instances and then trying to get
                // an object file from the container.
                for (uint32_t idx = 0; (create_object_container_callback = PluginManager::GetObjectContainerCreateCallbackAtIndex(idx)) != nullptr; ++idx)
                {
                    std::unique_ptr<ObjectContainer> object_container_ap(create_object_container_callback(module_sp, data_sp, data_offset, file, file_offset, file_size));

                    if (object_container_ap.get())
                        object_file_sp = object_container_ap->GetObjectFile(file);

                    if (object_file_sp.get())
                        return object_file_sp;
                }
            }
        }
    }
    // We didn't find it, so clear our shared pointer in case it
    // contains anything and return an empty shared pointer
    object_file_sp.reset();
    return object_file_sp;
}

ObjectFileSP
ObjectFile::FindPlugin (const lldb::ModuleSP &module_sp,
                        const ProcessSP &process_sp,
                        lldb::addr_t header_addr,
                        DataBufferSP &data_sp)
{
    ObjectFileSP object_file_sp;

    if (module_sp)
    {
        Timer scoped_timer (__PRETTY_FUNCTION__,
                            "ObjectFile::FindPlugin (module = %s, process = %p, header_addr = 0x%" PRIx64 ")",
                            module_sp->GetFileSpec().GetPath().c_str(),
                            static_cast<void*>(process_sp.get()), header_addr);
        uint32_t idx;

        // Check if this is a normal object file by iterating through
        // all object file plugin instances.
        ObjectFileCreateMemoryInstance create_callback;
        for (idx = 0; (create_callback = PluginManager::GetObjectFileCreateMemoryCallbackAtIndex(idx)) != nullptr; ++idx)
        {
            object_file_sp.reset (create_callback(module_sp, data_sp, process_sp, header_addr));
            if (object_file_sp.get())
                return object_file_sp;
        }
    }

    // We didn't find it, so clear our shared pointer in case it
    // contains anything and return an empty shared pointer
    object_file_sp.reset();
    return object_file_sp;
}

size_t
ObjectFile::GetModuleSpecifications (const FileSpec &file,
                                     lldb::offset_t file_offset,
                                     lldb::offset_t file_size,
                                     ModuleSpecList &specs)
{
    DataBufferSP data_sp (file.ReadFileContents(file_offset, 512));
    if (data_sp)
    {
        if (file_size == 0)
        {
            const lldb::offset_t actual_file_size = file.GetByteSize();
            if (actual_file_size > file_offset)
                file_size = actual_file_size - file_offset;
        }
        return ObjectFile::GetModuleSpecifications (file,       // file spec
                                                    data_sp,    // data bytes
                                                    0,          // data offset
                                                    file_offset,// file offset
                                                    file_size,  // file length
                                                    specs);
    }
    return 0;
}

size_t
ObjectFile::GetModuleSpecifications (const lldb_private::FileSpec& file,
                                     lldb::DataBufferSP& data_sp,
                                     lldb::offset_t data_offset,
                                     lldb::offset_t file_offset,
                                     lldb::offset_t file_size,
                                     lldb_private::ModuleSpecList &specs)
{
    const size_t initial_count = specs.GetSize();
    ObjectFileGetModuleSpecifications callback;
    uint32_t i;
    // Try the ObjectFile plug-ins
    for (i = 0; (callback = PluginManager::GetObjectFileGetModuleSpecificationsCallbackAtIndex(i)) != nullptr; ++i)
    {
        if (callback (file, data_sp, data_offset, file_offset, file_size, specs) > 0)
            return specs.GetSize() - initial_count;
    }

    // Try the ObjectContainer plug-ins
    for (i = 0; (callback = PluginManager::GetObjectContainerGetModuleSpecificationsCallbackAtIndex(i)) != nullptr; ++i)
    {
        if (callback (file, data_sp, data_offset, file_offset, file_size, specs) > 0)
            return specs.GetSize() - initial_count;
    }
    return 0;
}

ObjectFile::ObjectFile (const lldb::ModuleSP &module_sp,
                        const FileSpec *file_spec_ptr,
                        lldb::offset_t file_offset,
                        lldb::offset_t length,
                        const lldb::DataBufferSP& data_sp,
                        lldb::offset_t data_offset) :
    ModuleChild (module_sp),
    m_file (),  // This file could be different from the original module's file
    m_type (eTypeInvalid),
    m_strata (eStrataInvalid),
    m_file_offset (file_offset),
    m_length (length),
    m_data (),
    m_unwind_table (*this),
    m_process_wp(),
    m_memory_addr (LLDB_INVALID_ADDRESS),
    m_sections_ap(),
    m_symtab_ap (),
    m_synthetic_symbol_idx (0)
{
    if (file_spec_ptr)
        m_file = *file_spec_ptr;
    if (data_sp)
        m_data.SetData (data_sp, data_offset, length);
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
    if (log)
        log->Printf ("%p ObjectFile::ObjectFile() module = %p (%s), file = %s, file_offset = 0x%8.8" PRIx64 ", size = %" PRIu64,
                     static_cast<void*>(this),
                     static_cast<void*>(module_sp.get()),
                     module_sp->GetSpecificationDescription().c_str(),
                     m_file ? m_file.GetPath().c_str() : "<NULL>",
                     m_file_offset, m_length);
}


ObjectFile::ObjectFile (const lldb::ModuleSP &module_sp,
                        const ProcessSP &process_sp,
                        lldb::addr_t header_addr,
                        DataBufferSP& header_data_sp) :
    ModuleChild (module_sp),
    m_file (),
    m_type (eTypeInvalid),
    m_strata (eStrataInvalid),
    m_file_offset (0),
    m_length (0),
    m_data (),
    m_unwind_table (*this),
    m_process_wp (process_sp),
    m_memory_addr (header_addr),
    m_sections_ap(),
    m_symtab_ap (),
    m_synthetic_symbol_idx (0)
{
    if (header_data_sp)
        m_data.SetData (header_data_sp, 0, header_data_sp->GetByteSize());
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
    if (log)
        log->Printf ("%p ObjectFile::ObjectFile() module = %p (%s), process = %p, header_addr = 0x%" PRIx64,
                     static_cast<void*>(this),
                     static_cast<void*>(module_sp.get()),
                     module_sp->GetSpecificationDescription().c_str(),
                     static_cast<void*>(process_sp.get()), m_memory_addr);
}


ObjectFile::~ObjectFile()
{
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
    if (log)
        log->Printf ("%p ObjectFile::~ObjectFile ()\n",
                     static_cast<void*>(this));
}

bool
ObjectFile::SetModulesArchitecture (const ArchSpec &new_arch)
{
    ModuleSP module_sp (GetModule());
    if (module_sp)
        return module_sp->SetArchitecture (new_arch);
    return false;
}

AddressClass
ObjectFile::GetAddressClass (addr_t file_addr)
{
    Symtab *symtab = GetSymtab();
    if (symtab)
    {
        Symbol *symbol = symtab->FindSymbolContainingFileAddress(file_addr);
        if (symbol)
        {
            if (symbol->ValueIsAddress())
            {
                const SectionSP section_sp (symbol->GetAddressRef().GetSection());
                if (section_sp)
                {
                    const SectionType section_type = section_sp->GetType();
                    switch (section_type)
                    {
                    case eSectionTypeInvalid:
                        return eAddressClassUnknown;
                    case eSectionTypeCode:
                        return eAddressClassCode;
                    case eSectionTypeContainer:
                        return eAddressClassUnknown;
                    case eSectionTypeData:
                    case eSectionTypeDataCString:
                    case eSectionTypeDataCStringPointers:
                    case eSectionTypeDataSymbolAddress:
                    case eSectionTypeData4:
                    case eSectionTypeData8:
                    case eSectionTypeData16:
                    case eSectionTypeDataPointers:
                    case eSectionTypeZeroFill:
                    case eSectionTypeDataObjCMessageRefs:
                    case eSectionTypeDataObjCCFStrings:
                    case eSectionTypeGoSymtab:
                        return eAddressClassData;
                    case eSectionTypeDebug:
                    case eSectionTypeDWARFDebugAbbrev:
                    case eSectionTypeDWARFDebugAddr:
                    case eSectionTypeDWARFDebugAranges:
                    case eSectionTypeDWARFDebugFrame:
                    case eSectionTypeDWARFDebugInfo:
                    case eSectionTypeDWARFDebugLine:
                    case eSectionTypeDWARFDebugLoc:
                    case eSectionTypeDWARFDebugMacInfo:
                    case eSectionTypeDWARFDebugMacro:
                    case eSectionTypeDWARFDebugPubNames:
                    case eSectionTypeDWARFDebugPubTypes:
                    case eSectionTypeDWARFDebugRanges:
                    case eSectionTypeDWARFDebugStr:
                    case eSectionTypeDWARFDebugStrOffsets:
                    case eSectionTypeDWARFAppleNames:
                    case eSectionTypeDWARFAppleTypes:
                    case eSectionTypeDWARFAppleNamespaces:
                    case eSectionTypeDWARFAppleObjC:
                        return eAddressClassDebug;
                    case eSectionTypeEHFrame:
                    case eSectionTypeARMexidx:
                    case eSectionTypeARMextab:
                    case eSectionTypeCompactUnwind:
                        return eAddressClassRuntime;
                    case eSectionTypeELFSymbolTable:
                    case eSectionTypeELFDynamicSymbols:
                    case eSectionTypeELFRelocationEntries:
                    case eSectionTypeELFDynamicLinkInfo:
                    case eSectionTypeOther:
                        return eAddressClassUnknown;
                    case eSectionTypeAbsoluteAddress:
                        // In case of absolute sections decide the address class based on the symbol
                        // type because the section type isn't specify if it is a code or a data
                        // section.
                        break;
                    }
                }
            }

            const SymbolType symbol_type = symbol->GetType();
            switch (symbol_type)
            {
            case eSymbolTypeAny:            return eAddressClassUnknown;
            case eSymbolTypeAbsolute:       return eAddressClassUnknown;
            case eSymbolTypeCode:           return eAddressClassCode;
            case eSymbolTypeTrampoline:     return eAddressClassCode;
            case eSymbolTypeResolver:       return eAddressClassCode;
            case eSymbolTypeData:           return eAddressClassData;
            case eSymbolTypeRuntime:        return eAddressClassRuntime;
            case eSymbolTypeException:      return eAddressClassRuntime;
            case eSymbolTypeSourceFile:     return eAddressClassDebug;
            case eSymbolTypeHeaderFile:     return eAddressClassDebug;
            case eSymbolTypeObjectFile:     return eAddressClassDebug;
            case eSymbolTypeCommonBlock:    return eAddressClassDebug;
            case eSymbolTypeBlock:          return eAddressClassDebug;
            case eSymbolTypeLocal:          return eAddressClassData;
            case eSymbolTypeParam:          return eAddressClassData;
            case eSymbolTypeVariable:       return eAddressClassData;
            case eSymbolTypeVariableType:   return eAddressClassDebug;
            case eSymbolTypeLineEntry:      return eAddressClassDebug;
            case eSymbolTypeLineHeader:     return eAddressClassDebug;
            case eSymbolTypeScopeBegin:     return eAddressClassDebug;
            case eSymbolTypeScopeEnd:       return eAddressClassDebug;
            case eSymbolTypeAdditional:     return eAddressClassUnknown;
            case eSymbolTypeCompiler:       return eAddressClassDebug;
            case eSymbolTypeInstrumentation:return eAddressClassDebug;
            case eSymbolTypeUndefined:      return eAddressClassUnknown;
            case eSymbolTypeObjCClass:      return eAddressClassRuntime;
            case eSymbolTypeObjCMetaClass:  return eAddressClassRuntime;
            case eSymbolTypeObjCIVar:       return eAddressClassRuntime;
            case eSymbolTypeReExported:     return eAddressClassRuntime;
            }
        }
    }
    return eAddressClassUnknown;
}

DataBufferSP
ObjectFile::ReadMemory (const ProcessSP &process_sp, lldb::addr_t addr, size_t byte_size)
{
    DataBufferSP data_sp;
    if (process_sp)
    {
        std::unique_ptr<DataBufferHeap> data_ap (new DataBufferHeap (byte_size, 0));
        Error error;
        const size_t bytes_read = process_sp->ReadMemory (addr,
                                                          data_ap->GetBytes(),
                                                          data_ap->GetByteSize(),
                                                          error);
        if (bytes_read == byte_size)
            data_sp.reset (data_ap.release());
    }
    return data_sp;
}

size_t
ObjectFile::GetData (lldb::offset_t offset, size_t length, DataExtractor &data) const
{
    // The entire file has already been mmap'ed into m_data, so just copy from there
    // as the back mmap buffer will be shared with shared pointers.
    return data.SetData (m_data, offset, length);
}

size_t
ObjectFile::CopyData (lldb::offset_t offset, size_t length, void *dst) const
{
    // The entire file has already been mmap'ed into m_data, so just copy from there
    // Note that the data remains in target byte order.
    return m_data.CopyData (offset, length, dst);
}


size_t
ObjectFile::ReadSectionData (const Section *section, lldb::offset_t section_offset, void *dst, size_t dst_len) const
{
    assert(section);
    section_offset *= section->GetTargetByteSize();

    // If some other objectfile owns this data, pass this to them.
    if (section->GetObjectFile() != this)
        return section->GetObjectFile()->ReadSectionData (section, section_offset, dst, dst_len);

    if (IsInMemory())
    {
        ProcessSP process_sp (m_process_wp.lock());
        if (process_sp)
        {
            Error error;
            const addr_t base_load_addr = section->GetLoadBaseAddress (&process_sp->GetTarget());
            if (base_load_addr != LLDB_INVALID_ADDRESS)
                return process_sp->ReadMemory (base_load_addr + section_offset, dst, dst_len, error);
        }
    }
    else
    {
        const lldb::offset_t section_file_size = section->GetFileSize();
        if (section_offset < section_file_size)
        {
            const size_t section_bytes_left = section_file_size - section_offset;
            size_t section_dst_len = dst_len;
            if (section_dst_len > section_bytes_left)
                section_dst_len = section_bytes_left;
            return CopyData (section->GetFileOffset() + section_offset, section_dst_len, dst);
        }
        else
        {
            if (section->GetType() == eSectionTypeZeroFill)
            {
                const uint64_t section_size = section->GetByteSize();
                const uint64_t section_bytes_left = section_size - section_offset;
                uint64_t section_dst_len = dst_len;
                if (section_dst_len > section_bytes_left)
                    section_dst_len = section_bytes_left;
                memset(dst, 0, section_dst_len);
                return section_dst_len;
            }
        }
    }
    return 0;
}

//----------------------------------------------------------------------
// Get the section data the file on disk
//----------------------------------------------------------------------
size_t
ObjectFile::ReadSectionData (const Section *section, DataExtractor& section_data) const
{
    // If some other objectfile owns this data, pass this to them.
    if (section->GetObjectFile() != this)
        return section->GetObjectFile()->ReadSectionData (section, section_data);

    if (IsInMemory())
    {
        ProcessSP process_sp (m_process_wp.lock());
        if (process_sp)
        {
            const addr_t base_load_addr = section->GetLoadBaseAddress (&process_sp->GetTarget());
            if (base_load_addr != LLDB_INVALID_ADDRESS)
            {
                DataBufferSP data_sp (ReadMemory (process_sp, base_load_addr, section->GetByteSize()));
                if (data_sp)
                {
                    section_data.SetData (data_sp, 0, data_sp->GetByteSize());
                    section_data.SetByteOrder (process_sp->GetByteOrder());
                    section_data.SetAddressByteSize (process_sp->GetAddressByteSize());
                    return section_data.GetByteSize();
                }
            }
        }
        return GetData(section->GetFileOffset(), section->GetFileSize(), section_data);
    }
    else
    {
        // The object file now contains a full mmap'ed copy of the object file data, so just use this
        return MemoryMapSectionData (section, section_data);
    }
}

size_t
ObjectFile::MemoryMapSectionData (const Section *section, DataExtractor& section_data) const
{
    // If some other objectfile owns this data, pass this to them.
    if (section->GetObjectFile() != this)
        return section->GetObjectFile()->MemoryMapSectionData (section, section_data);

    if (IsInMemory())
    {
        return ReadSectionData (section, section_data);
    }
    else
    {
        // The object file now contains a full mmap'ed copy of the object file data, so just use this
        return GetData(section->GetFileOffset(), section->GetFileSize(), section_data);
    }
}


bool
ObjectFile::SplitArchivePathWithObject (const char *path_with_object, FileSpec &archive_file, ConstString &archive_object, bool must_exist)
{
    RegularExpression g_object_regex("(.*)\\(([^\\)]+)\\)$");
    RegularExpression::Match regex_match(2);
    if (g_object_regex.Execute (path_with_object, &regex_match))
    {
        std::string path;
        std::string obj;
        if (regex_match.GetMatchAtIndex (path_with_object, 1, path) &&
            regex_match.GetMatchAtIndex (path_with_object, 2, obj))
        {
            archive_file.SetFile (path.c_str(), false);
            archive_object.SetCString(obj.c_str());
            if (must_exist && !archive_file.Exists())
                return false;
            return true;
        }
    }
    return false;
}

void
ObjectFile::ClearSymtab ()
{
    ModuleSP module_sp(GetModule());
    if (module_sp)
    {
        std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
        Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
        if (log)
            log->Printf ("%p ObjectFile::ClearSymtab () symtab = %p",
                         static_cast<void*>(this),
                         static_cast<void*>(m_symtab_ap.get()));
        m_symtab_ap.reset();
    }
}

SectionList *
ObjectFile::GetSectionList(bool update_module_section_list)
{
    if (m_sections_ap.get() == nullptr)
    {
        if (update_module_section_list)
        {
            ModuleSP module_sp(GetModule());
            if (module_sp)
            {
                std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
                CreateSections(*module_sp->GetUnifiedSectionList());
            }
        }
        else
        {
            SectionList unified_section_list;
            CreateSections(unified_section_list);
        }
    }
    return m_sections_ap.get();
}

lldb::SymbolType
ObjectFile::GetSymbolTypeFromName (llvm::StringRef name,
                                   lldb::SymbolType symbol_type_hint)
{
    if (!name.empty())
    {
        if (name.startswith("_OBJC_"))
        {
            // ObjC
            if (name.startswith("_OBJC_CLASS_$_"))
                return lldb::eSymbolTypeObjCClass;
            if (name.startswith("_OBJC_METACLASS_$_"))
                return lldb::eSymbolTypeObjCMetaClass;
            if (name.startswith("_OBJC_IVAR_$_"))
                return lldb::eSymbolTypeObjCIVar;
        }
        else if (name.startswith(".objc_class_name_"))
        {
            // ObjC v1
            return lldb::eSymbolTypeObjCClass;
        }
    }
    return symbol_type_hint;
}

ConstString
ObjectFile::GetNextSyntheticSymbolName()
{
    StreamString ss;
    ConstString file_name = GetModule()->GetFileSpec().GetFilename();
    ss.Printf("___lldb_unnamed_symbol%u$$%s", ++m_synthetic_symbol_idx, file_name.GetCString());
    return ConstString(ss.GetData());
}