Make SymbolFileDWARF::GetCachedSectionData thread safe

[tberghammer]

Summary

Make SymbolFileDWARF::GetCachedSectionData thread safe

[tberghammer]

Use std::call_once instead of a std::atomic+std::mutex combination based on some offline discussion with Pavel

[clayborg]

Looks good.

[labath]

The new version of the patch looks much cleaner than the old one. Thanks.

source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

641 ↗

(On Diff #38019)

shorter and probably more efficient:
std::call_once(m_flag, &SFD::LoadSectionData, this, sect_type, std::ref(data_segment.m_data));

lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h

 //===-- SymbolFileDWARF.h --------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SymbolFileDWARF_SymbolFileDWARF_h_
 #define SymbolFileDWARF_SymbolFileDWARF_h_
 
 // C Includes
 // C++ Includes
 #include <list>
 #include <map>
+#include <mutex>
 #include <set>
 #include <vector>
 
 // Other libraries and framework includes
 #include "llvm/ADT/DenseMap.h"
 
 #include "lldb/lldb-private.h"
 #include "lldb/Core/ConstString.h"
public:
     DWARFDebugInfo*
     DebugInfo();
 
     const DWARFDebugInfo*
     DebugInfo() const;
 
     DWARFDebugRanges*
     DebugRanges();
+
     const DWARFDebugRanges*
     DebugRanges() const;
 
-    virtual const lldb_private::DWARFDataExtractor&
-    GetCachedSectionData (uint32_t got_flag, 
-                          lldb::SectionType sect_type, 
-                          lldb_private::DWARFDataExtractor &data);
-
     static bool
     SupportedVersion(uint16_t version);
 
     DWARFDIE
     GetDeclContextDIEContainingDIE (const DWARFDIE &die);
 
-    lldb_private::Flags&
-    GetFlags ()
-    {
-        return m_flags;
-    }
-
-    const lldb_private::Flags&
-    GetFlags () const
-    {
-        return m_flags;
-    }
-
     bool
     HasForwardDeclForClangType (const lldb_private::CompilerType &compiler_type);
 
     lldb_private::CompileUnit*
     GetCompUnitForDWARFCompUnit(DWARFCompileUnit* dwarf_cu,
                                 uint32_t cu_idx = UINT32_MAX);
 
     lldb::user_id_t
public:
     GetLocationListFormat() const;
 
 protected:
     typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb_private::Type *> DIEToTypePtr;
     typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb::VariableSP> DIEToVariableSP;
     typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb::opaque_compiler_type_t> DIEToClangType;
     typedef llvm::DenseMap<lldb::opaque_compiler_type_t, DIERef> ClangTypeToDIE;
 
-    enum
+    struct DWARFDataSegment
     {
-        flagsGotDebugAbbrevData     = (1 << 0),
-        flagsGotDebugAddrData       = (1 << 1),
-        flagsGotDebugArangesData    = (1 << 2),
-        flagsGotDebugFrameData      = (1 << 3),
-        flagsGotDebugInfoData       = (1 << 4),
-        flagsGotDebugLineData       = (1 << 5),
-        flagsGotDebugLocData        = (1 << 6),
-        flagsGotDebugMacInfoData    = (1 << 7),
-        flagsGotDebugPubNamesData   = (1 << 8),
-        flagsGotDebugPubTypesData   = (1 << 9),
-        flagsGotDebugRangesData     = (1 << 10),
-        flagsGotDebugStrData        = (1 << 11),
-        flagsGotDebugStrOffsetsData = (1 << 12),
-        flagsGotAppleNamesData      = (1 << 13),
-        flagsGotAppleTypesData      = (1 << 14),
-        flagsGotAppleNamespacesData = (1 << 15),
-        flagsGotAppleObjCData       = (1 << 16)
+        std::once_flag                   m_flag;
+        lldb_private::DWARFDataExtractor m_data;
     };
-    
+    DISALLOW_COPY_AND_ASSIGN (SymbolFileDWARF);
+
+    const lldb_private::DWARFDataExtractor&
+    GetCachedSectionData (lldb::SectionType sect_type, DWARFDataSegment& data_segment);
+
+    virtual void
+    LoadSectionData (lldb::SectionType sect_type, lldb_private::DWARFDataExtractor& data);
+
     bool
     DeclContextMatchesThisSymbolFile (const lldb_private::CompilerDeclContext *decl_ctx);
 
     bool
     DIEInDeclContext (const lldb_private::CompilerDeclContext *parent_decl_ctx,
                       const DWARFDIE &die);
 
-    DISALLOW_COPY_AND_ASSIGN (SymbolFileDWARF);
-
     virtual DWARFCompileUnit*
     GetDWARFCompileUnit (lldb_private::CompileUnit *comp_unit);
 
     DWARFCompileUnit*
     GetNextUnparsedDWARFCompileUnit (DWARFCompileUnit* prev_cu);
 
     bool
     GetFunction (const DWARFDIE &die,
protected:
     virtual DIEToClangType&
     GetForwardDeclDieToClangType() { return m_forward_decl_die_to_clang_type; }
 
     virtual ClangTypeToDIE&
     GetForwardDeclClangTypeToDie() { return m_forward_decl_clang_type_to_die; }
 
     lldb::ModuleWP                        m_debug_map_module_wp;
     SymbolFileDWARFDebugMap *             m_debug_map_symfile;
-    lldb_private::Flags                   m_flags;
     lldb_private::DWARFDataExtractor      m_dwarf_data;
-    lldb_private::DWARFDataExtractor      m_data_debug_abbrev;
-    lldb_private::DWARFDataExtractor      m_data_debug_addr;
-    lldb_private::DWARFDataExtractor      m_data_debug_aranges;
-    lldb_private::DWARFDataExtractor      m_data_debug_frame;
-    lldb_private::DWARFDataExtractor      m_data_debug_info;
-    lldb_private::DWARFDataExtractor      m_data_debug_line;
-    lldb_private::DWARFDataExtractor      m_data_debug_loc;
-    lldb_private::DWARFDataExtractor      m_data_debug_ranges;
-    lldb_private::DWARFDataExtractor      m_data_debug_str;
-    lldb_private::DWARFDataExtractor      m_data_debug_str_offsets;
-    lldb_private::DWARFDataExtractor      m_data_apple_names;
-    lldb_private::DWARFDataExtractor      m_data_apple_types;
-    lldb_private::DWARFDataExtractor      m_data_apple_namespaces;
-    lldb_private::DWARFDataExtractor      m_data_apple_objc;
+
+    DWARFDataSegment                      m_data_debug_abbrev;
+    DWARFDataSegment                      m_data_debug_addr;
+    DWARFDataSegment                      m_data_debug_aranges;
+    DWARFDataSegment                      m_data_debug_frame;
+    DWARFDataSegment                      m_data_debug_info;
+    DWARFDataSegment                      m_data_debug_line;
+    DWARFDataSegment                      m_data_debug_loc;
+    DWARFDataSegment                      m_data_debug_ranges;
+    DWARFDataSegment                      m_data_debug_str;
+    DWARFDataSegment                      m_data_debug_str_offsets;
+    DWARFDataSegment                      m_data_apple_names;
+    DWARFDataSegment                      m_data_apple_types;
+    DWARFDataSegment                      m_data_apple_namespaces;
+    DWARFDataSegment                      m_data_apple_objc;
 
     // The unique pointer items below are generated on demand if and when someone accesses
     // them through a non const version of this class.
     std::unique_ptr<DWARFDebugAbbrev>     m_abbr;
     std::unique_ptr<DWARFDebugInfo>       m_info;
     std::unique_ptr<DWARFDebugLine>       m_line;
     std::unique_ptr<DWARFMappedHash::MemoryTable> m_apple_names_ap;
     std::unique_ptr<DWARFMappedHash::MemoryTable> m_apple_types_ap;

lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

 }
 
 
 SymbolFileDWARF::SymbolFileDWARF(ObjectFile* objfile) :
     SymbolFile (objfile),
     UserID (0),  // Used by SymbolFileDWARFDebugMap to when this class parses .o files to contain the .o file index/ID
     m_debug_map_module_wp (),
     m_debug_map_symfile (NULL),
-    m_flags(),
     m_data_debug_abbrev (),
     m_data_debug_aranges (),
     m_data_debug_frame (),
     m_data_debug_info (),
     m_data_debug_line (),
     m_data_debug_loc (),
     m_data_debug_ranges (),
     m_data_debug_str (),

 
 void
 SymbolFileDWARF::InitializeObject()
 {
     ModuleSP module_sp (m_obj_file->GetModule());
     if (module_sp)
     {
         const SectionList *section_list = module_sp->GetSectionList();
-
         const Section* section = section_list->FindSectionByName(GetDWARFMachOSegmentName ()).get();
 
         // Memory map the DWARF mach-o segment so we have everything mmap'ed
         // to keep our heap memory usage down.
         if (section)
             m_obj_file->MemoryMapSectionData(section, m_dwarf_data);
     }
+
     get_apple_names_data();
-    if (m_data_apple_names.GetByteSize() > 0)
+    if (m_data_apple_names.m_data.GetByteSize() > 0)
     {
-        m_apple_names_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_names, get_debug_str_data(), ".apple_names"));
+        m_apple_names_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_names.m_data,
+                                                                  get_debug_str_data(),
+                                                                  ".apple_names"));
         if (m_apple_names_ap->IsValid())
             m_using_apple_tables = true;
         else
             m_apple_names_ap.reset();
     }
     get_apple_types_data();
-    if (m_data_apple_types.GetByteSize() > 0)
+    if (m_data_apple_types.m_data.GetByteSize() > 0)
     {
-        m_apple_types_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_types, get_debug_str_data(), ".apple_types"));
+        m_apple_types_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_types.m_data,
+                                                                  get_debug_str_data(),
+                                                                  ".apple_types"));
         if (m_apple_types_ap->IsValid())
             m_using_apple_tables = true;
         else
             m_apple_types_ap.reset();
     }
 
     get_apple_namespaces_data();
-    if (m_data_apple_namespaces.GetByteSize() > 0)
+    if (m_data_apple_namespaces.m_data.GetByteSize() > 0)
     {
-        m_apple_namespaces_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_namespaces, get_debug_str_data(), ".apple_namespaces"));
+        m_apple_namespaces_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_namespaces.m_data,
+                                                                       get_debug_str_data(),
+                                                                       ".apple_namespaces"));
         if (m_apple_namespaces_ap->IsValid())
             m_using_apple_tables = true;
         else
             m_apple_namespaces_ap.reset();
     }
 
     get_apple_objc_data();
-    if (m_data_apple_objc.GetByteSize() > 0)
+    if (m_data_apple_objc.m_data.GetByteSize() > 0)
     {
-        m_apple_objc_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_objc, get_debug_str_data(), ".apple_objc"));
+        m_apple_objc_ap.reset (new DWARFMappedHash::MemoryTable (m_data_apple_objc.m_data,
+                                                                 get_debug_str_data(),
+                                                                 ".apple_objc"));
         if (m_apple_objc_ap->IsValid())
             m_using_apple_tables = true;
         else
             m_apple_objc_ap.reset();
     }
 }
 
 bool
if (m_obj_file != NULL)
         section = section_list->FindSectionByType (eSectionTypeDWARFDebugInfo, true).get();
         if (section != NULL)
         {
             debug_info_file_size = section->GetFileSize();
 
             section = section_list->FindSectionByType (eSectionTypeDWARFDebugAbbrev, true).get();
             if (section)
                 debug_abbrev_file_size = section->GetFileSize();
-            else
-                m_flags.Set (flagsGotDebugAbbrevData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugAranges, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugArangesData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugFrame, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugFrameData);
 
             section = section_list->FindSectionByType (eSectionTypeDWARFDebugLine, true).get();
             if (section)
                 debug_line_file_size = section->GetFileSize();
-            else
-                m_flags.Set (flagsGotDebugLineData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugLoc, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugLocData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugMacInfo, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugMacInfoData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugPubNames, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugPubNamesData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugPubTypes, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugPubTypesData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugRanges, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugRangesData);
-
-            section = section_list->FindSectionByType (eSectionTypeDWARFDebugStr, true).get();
-            if (!section)
-                m_flags.Set (flagsGotDebugStrData);
         }
         else
         {
             const char *symfile_dir_cstr = m_obj_file->GetFileSpec().GetDirectory().GetCString();
             if (symfile_dir_cstr)
             {
                 if (strcasestr(symfile_dir_cstr, ".dsym"))
                 {
if (m_obj_file != NULL)
 
         if (debug_line_file_size > 0)
             abilities |= LineTables;
     }
     return abilities;
 }
 
 const DWARFDataExtractor&
-SymbolFileDWARF::GetCachedSectionData (uint32_t got_flag, SectionType sect_type, DWARFDataExtractor &data)
+SymbolFileDWARF::GetCachedSectionData (lldb::SectionType sect_type, DWARFDataSegment& data_segment)
 {
-    if (m_flags.IsClear (got_flag))
-    {
-        ModuleSP module_sp (m_obj_file->GetModule());
-        m_flags.Set (got_flag);
-        const SectionList *section_list = module_sp->GetSectionList();
-        if (section_list)
-        {
-            SectionSP section_sp (section_list->FindSectionByType(sect_type, true));
-            if (section_sp)
-            {
-                // See if we memory mapped the DWARF segment?
-                if (m_dwarf_data.GetByteSize())
-                {
-                    data.SetData(m_dwarf_data, section_sp->GetOffset (), section_sp->GetFileSize());
-                }
-                else
-                {
-                    if (m_obj_file->ReadSectionData (section_sp.get(), data) == 0)
-                        data.Clear();
-                }
-            }
-        }
-    }
-    return data;
-}
+    std::call_once(data_segment.m_flag,
+                   &SymbolFileDWARF::LoadSectionData,
+                   this,
+                   sect_type,
+                   std::ref(data_segment.m_data));
+    return data_segment.m_data;
+}
+
+void
+SymbolFileDWARF::LoadSectionData (lldb::SectionType sect_type, DWARFDataExtractor& data)
+                data.SetData(m_dwarf_data, section_sp->GetOffset(), section_sp->GetFileSize());
+                if (m_obj_file->ReadSectionData(section_sp.get(), data) == 0)
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_abbrev_data()
 {
-    return GetCachedSectionData (flagsGotDebugAbbrevData, eSectionTypeDWARFDebugAbbrev, m_data_debug_abbrev);
+    return GetCachedSectionData (eSectionTypeDWARFDebugAbbrev, m_data_debug_abbrev);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_addr_data()
 {
-    return GetCachedSectionData (flagsGotDebugAddrData, eSectionTypeDWARFDebugAddr, m_data_debug_addr);
+    return GetCachedSectionData (eSectionTypeDWARFDebugAddr, m_data_debug_addr);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_aranges_data()
 {
-    return GetCachedSectionData (flagsGotDebugArangesData, eSectionTypeDWARFDebugAranges, m_data_debug_aranges);
+    return GetCachedSectionData (eSectionTypeDWARFDebugAranges, m_data_debug_aranges);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_frame_data()
 {
-    return GetCachedSectionData (flagsGotDebugFrameData, eSectionTypeDWARFDebugFrame, m_data_debug_frame);
+    return GetCachedSectionData (eSectionTypeDWARFDebugFrame, m_data_debug_frame);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_info_data()
 {
-    return GetCachedSectionData (flagsGotDebugInfoData, eSectionTypeDWARFDebugInfo, m_data_debug_info);
+    return GetCachedSectionData (eSectionTypeDWARFDebugInfo, m_data_debug_info);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_line_data()
 {
-    return GetCachedSectionData (flagsGotDebugLineData, eSectionTypeDWARFDebugLine, m_data_debug_line);
+    return GetCachedSectionData (eSectionTypeDWARFDebugLine, m_data_debug_line);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_loc_data()
 {
-    return GetCachedSectionData (flagsGotDebugLocData, eSectionTypeDWARFDebugLoc, m_data_debug_loc);
+    return GetCachedSectionData (eSectionTypeDWARFDebugLoc, m_data_debug_loc);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_ranges_data()
 {
-    return GetCachedSectionData (flagsGotDebugRangesData, eSectionTypeDWARFDebugRanges, m_data_debug_ranges);
+    return GetCachedSectionData (eSectionTypeDWARFDebugRanges, m_data_debug_ranges);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_str_data()
 {
-    return GetCachedSectionData (flagsGotDebugStrData, eSectionTypeDWARFDebugStr, m_data_debug_str);
+    return GetCachedSectionData (eSectionTypeDWARFDebugStr, m_data_debug_str);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_debug_str_offsets_data()
 {
-    return GetCachedSectionData (flagsGotDebugStrOffsetsData, eSectionTypeDWARFDebugStrOffsets, m_data_debug_str_offsets);
+    return GetCachedSectionData (eSectionTypeDWARFDebugStrOffsets, m_data_debug_str_offsets);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_apple_names_data()
 {
-    return GetCachedSectionData (flagsGotAppleNamesData, eSectionTypeDWARFAppleNames, m_data_apple_names);
+    return GetCachedSectionData (eSectionTypeDWARFAppleNames, m_data_apple_names);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_apple_types_data()
 {
-    return GetCachedSectionData (flagsGotAppleTypesData, eSectionTypeDWARFAppleTypes, m_data_apple_types);
+    return GetCachedSectionData (eSectionTypeDWARFAppleTypes, m_data_apple_types);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_apple_namespaces_data()
 {
-    return GetCachedSectionData (flagsGotAppleNamespacesData, eSectionTypeDWARFAppleNamespaces, m_data_apple_namespaces);
+    return GetCachedSectionData (eSectionTypeDWARFAppleNamespaces, m_data_apple_namespaces);
 }
 
 const DWARFDataExtractor&
 SymbolFileDWARF::get_apple_objc_data()
 {
-    return GetCachedSectionData (flagsGotAppleObjCData, eSectionTypeDWARFAppleObjC, m_data_apple_objc);
+    return GetCachedSectionData (eSectionTypeDWARFAppleObjC, m_data_apple_objc);
 }
 
 
 DWARFDebugAbbrev*
 SymbolFileDWARF::DebugAbbrev()
 {
     if (m_abbr.get() == NULL)
     {

lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h

 
 class SymbolFileDWARFDwo : public SymbolFileDWARF
 {
 public:
     SymbolFileDWARFDwo(lldb::ObjectFileSP objfile, DWARFCompileUnit* dwarf_cu);
 
     ~SymbolFileDWARFDwo() override = default;
     
-    const lldb_private::DWARFDataExtractor&
-    GetCachedSectionData(uint32_t got_flag,
-                         lldb::SectionType sect_type,
-                         lldb_private::DWARFDataExtractor &data) override;
-    
     lldb::CompUnitSP
     ParseCompileUnit(DWARFCompileUnit* dwarf_cu, uint32_t cu_idx) override;
 
     DWARFCompileUnit*
     GetCompileUnit();
 
     DWARFCompileUnit*
     GetDWARFCompileUnit(lldb_private::CompileUnit *comp_unit) override;
 
     lldb_private::DWARFExpression::LocationListFormat
     GetLocationListFormat() const override;
 
     lldb_private::TypeSystem*
     GetTypeSystemForLanguage(lldb::LanguageType language) override;
 
 protected:
+    void
+    LoadSectionData (lldb::SectionType sect_type, lldb_private::DWARFDataExtractor& data) override;
+
     DIEToTypePtr&
     GetDIEToType() override;
 
     DIEToVariableSP&
     GetDIEToVariable() override;
     
     DIEToClangType&
     GetForwardDeclDieToClangType() override;

lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp

 SymbolFileDWARFDwo::SymbolFileDWARFDwo(ObjectFileSP objfile, DWARFCompileUnit* dwarf_cu) :
     SymbolFileDWARF(objfile.get()),
     m_obj_file_sp(objfile),
     m_base_dwarf_cu(dwarf_cu)
 {
     SetID(((lldb::user_id_t)dwarf_cu->GetOffset())<<32);
 }
 
-const lldb_private::DWARFDataExtractor&
-SymbolFileDWARFDwo::GetCachedSectionData(uint32_t got_flag,
-                                         lldb::SectionType sect_type,
-                                         lldb_private::DWARFDataExtractor &data)
+void
+SymbolFileDWARFDwo::LoadSectionData (lldb::SectionType sect_type, DWARFDataExtractor& data)
 {
-    if (!m_flags.IsClear (got_flag))
-        return data;
-
     const SectionList* section_list = m_obj_file->GetSectionList(false /* update_module_section_list */);
     if (section_list)
     {
         SectionSP section_sp (section_list->FindSectionByType(sect_type, true));
         if (section_sp)
         {
             // See if we memory mapped the DWARF segment?
             if (m_dwarf_data.GetByteSize())
             {
                 data.SetData(m_dwarf_data, section_sp->GetOffset(), section_sp->GetFileSize());
-                m_flags.Set (got_flag);
-                return data;
+                return;
             }
 
             if (m_obj_file->ReadSectionData(section_sp.get(), data) != 0)
-            {
-                m_flags.Set (got_flag);
-                return data;
-            }
+                return;
 
             data.Clear();
         }
     }
-    return SymbolFileDWARF::GetCachedSectionData(got_flag, sect_type, data);
+
+    SymbolFileDWARF::LoadSectionData(sect_type, data);
 }
 
 lldb::CompUnitSP
 SymbolFileDWARFDwo::ParseCompileUnit(DWARFCompileUnit* dwarf_cu, uint32_t cu_idx)
 {
     assert(GetCompileUnit() == dwarf_cu && "SymbolFileDWARFDwo::ParseCompileUnit called with incompatible compile unit");
     return GetBaseSymbolFile()->ParseCompileUnit(m_base_dwarf_cu, UINT32_MAX);
 }