[LLDB] - Support the single file split DWARF.

[grimar]

Summary

DWARF5 spec describes single file split dwarf case (when .dwo sections are in the .o files).

Problem is that LLDB does not work correctly in that case. The issue is that, for example, both .debug_info and .debug_info.dwo
has the same type: eSectionTypeDWARFDebugInfo. And when code searches section by type it might find the regular debug section
and not the .dwo one. It seems can be easily fixed though, patch shows the fix I am suggesting.

Note that currently, clang is unable to produce such output, the patch is on review atm: D52296.
It is still would be possible to use assembler to produce such files though.
But the test case refers to the flag from the review mentioned.

[clayborg]

So the main questions is: do we need a new section enum called eSectionTypeDWARFDebugInfoDWO? If so, then this patch changes. I think I would prefer adding a new enum.

source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp

0–1

If dwo has a unique section name, just name a new enum for the .debug_info.dwo.

[labath]

I believe you should be able to use lldb-test to write this kind of a test. I am thinking of a sequence like:

yaml2obj %p/Inputs/test.yaml > %t/test.yaml
yaml2obj %p/Inputs/test.o.yaml > %t/test.o.yaml
lldb-test breakpoint %t/test.yaml %s | FileCheck %s
b main
CHECK-LABEL: b main
CHECK: Address: {{.*}}main + 13 at test.cpp:2:3

b foo
CHECK-LABEL: b foo
CHECK: Address: {{.*}}foo() + 4 at test.cpp:6:1

You can look at existing tests in lit/Breakpoints for details.

[grimar]

Thanks for all the comments!

In D52403#1243127, @clayborg wrote:

So the main questions is: do we need a new section enum called eSectionTypeDWARFDebugInfoDWO? If so, then this patch changes. I think I would prefer adding a new enum.

Yeah, that is what I thought at the first place too. I found that when code looks for some section, it seems sometimes assumes it can find .dwo section by regular section enum value.
I thought that time that much more changes might be required (for example, introducing enum values for each .dwo section and perhaps fixing callers)
and so selected the simplest solution (this patch), because original code already used filtering by section name "dwo" suffix.

I'll try to investigate it again, want to check a few ideas I have in mind.

[grimar]

• Addressed review comments.

[clayborg]

Just a few fixes. Looking good.

include/lldb/lldb-enumerations.h

643–660

Add all of these to the end of this enum for API stability since this is a public header used in the API. If an older binary runs against a newer liblldb.so, all of these enums will be off.

source/Symbol/ObjectFile.cpp

347

Check for other ObjectFile subclasses that override this function. I believe ObjectFileMachO does.

[grimar]

• Addressed review comments.

include/lldb/lldb-enumerations.h

643–660

Done.

source/Symbol/ObjectFile.cpp

347

Yes, and my patch already has the change for ObjectFileMachO :)
All other classes are fine too I think.

[clayborg]

Looks good!

[grimar]

Thanks for the review! It still depends on -gsingle-file-split-dwarf (D52403), I'll wait for it some time.
It should be possible to rewrite the comment in the test case to avoid mentioning the flag, but I would prefer to use it.

[grimar]

Committed as rLLDB346848.
The commit message has a wrong review link by mistake.

include/lldb/lldb-enumerations.h

enum SectionType {
   eSectionTypeData8,
   eSectionTypeData16,
   eSectionTypeDataPointers,
   eSectionTypeDebug,
   eSectionTypeZeroFill,
   eSectionTypeDataObjCMessageRefs, // Pointer to function pointer + selector
   eSectionTypeDataObjCCFStrings, // Objective-C const CFString/NSString objects
   eSectionTypeDWARFDebugAbbrev,
   eSectionTypeDWARFDebugAddr,
   eSectionTypeDWARFDebugAranges,
   eSectionTypeDWARFDebugCuIndex,
   eSectionTypeDWARFDebugFrame,
   eSectionTypeDWARFDebugInfo,
   eSectionTypeDWARFDebugLine,
   eSectionTypeDWARFDebugLoc,
   eSectionTypeDWARFDebugMacInfo,
   eSectionTypeDWARFDebugMacro,
   eSectionTypeDWARFDebugPubNames,
   eSectionTypeDWARFDebugPubTypes,
   eSectionTypeDWARFDebugRanges,
   eSectionTypeDWARFDebugStr,
   eSectionTypeDWARFDebugStrOffsets,
   eSectionTypeDWARFAppleNames,
   eSectionTypeDWARFAppleTypes,
   eSectionTypeDWARFAppleNamespaces,
   eSectionTypeDWARFAppleObjC,
   eSectionTypeELFSymbolTable,       // Elf SHT_SYMTAB section
   eSectionTypeELFDynamicSymbols,    // Elf SHT_DYNSYM section
   eSectionTypeELFRelocationEntries, // Elf SHT_REL or SHT_REL section
   eSectionTypeELFDynamicLinkInfo,   // Elf SHT_DYNAMIC section
   eSectionTypeEHFrame,
   eSectionTypeARMexidx,
   eSectionTypeARMextab,
   eSectionTypeCompactUnwind, // compact unwind section in Mach-O,
                              // __TEXT,__unwind_info
   eSectionTypeGoSymtab,
   eSectionTypeAbsoluteAddress, // Dummy section for symbols with absolute
                                // address
   eSectionTypeDWARFGNUDebugAltLink,
   eSectionTypeDWARFDebugTypes, // DWARF .debug_types section
   eSectionTypeDWARFDebugNames, // DWARF v5 .debug_names
   eSectionTypeOther,
   eSectionTypeDWARFDebugLineStr, // DWARF v5 .debug_line_str
+  eSectionTypeDWARFDebugAbbrevDwo,
+  eSectionTypeDWARFDebugInfoDwo,
+  eSectionTypeDWARFDebugStrDwo,
+  eSectionTypeDWARFDebugStrOffsetsDwo,
 };
 
 FLAGS_ENUM(EmulateInstructionOptions){
     eEmulateInstructionOptionNone = (0u),
     eEmulateInstructionOptionAutoAdvancePC = (1u << 0),
     eEmulateInstructionOptionIgnoreConditions = (1u << 1)};
 
 FLAGS_ENUM(FunctionNameType){

lit/Breakpoint/Inputs/single-file-split-dwarf.o.yaml

+--- !ELF
+FileHeader:      
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:        
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         554889E531C0C745FC000000005DC390554889E55DC3
+  - Name:            .debug_str_offsets
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         0C000000050000000000000000000000
+  - Name:            .debug_str
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x0000000000000001
+    Content:         746573742E6F002F686F6D652F756D622F74657374735F323031382F39355F6C6C64622F726570726F2F6477617266355F73706C69745F73696E676C655F66696C652F707265706172655F73616D706C65006D61696E00666F6F005F5A33666F6F7600696E7400
+  - Name:            .debug_loc.dwo
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXCLUDE ]
+    AddressAlign:    0x0000000000000001
+    Content:         ''
+  - Name:            .debug_abbrev
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         01110010177217B042251B25B44219B3421711011206000000
+  - Name:            .debug_info
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         2B00000005000408000000003F4B7684A29835B9010000000000000000000100000000000000000000000016000000
+  - Name:            .debug_macinfo
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         '00'
+  - Name:            .debug_str_offsets.dwo
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXCLUDE ]
+    AddressAlign:    0x0000000000000001
+    Content:         200000000500000000000000070000002A00000033000000380000003C00000044000000
+  - Name:            .debug_str.dwo
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXCLUDE, SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x0000000000000001
+    Content:         746573742E6F00636C616E672076657273696F6E20382E302E3020287472756E6B203334323731382900746573742E637070006D61696E00696E74005F5A33666F6F7600666F6F00
+  - Name:            .debug_info.dwo
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXCLUDE ]
+    AddressAlign:    0x0000000000000001
+    Content:         3600000005000508000000003F4B7684A29835B901000104000202000F0000000156030101350000000301060000000156050601050404050400
+  - Name:            .debug_abbrev.dwo
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXCLUDE ]
+    AddressAlign:    0x0000000000000001
+    Content:         011101B042252525130503250000022E0011813E1206401803253A0B3B0B49133F190000032E0011813E120640186E2503253A0B3B0B3F19000004240003253E0B0B0B000000
+  - Name:            .debug_addr
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         '140000000500080000000000000000000000000000000000'
+  - Name:            .debug_names
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000004
+    Content:         A00000000500000001000000000000000000000004000000040000000D000000080000004C4C564D3037303000000000010000000200000003000000040000003080880B8973880B6A7F9A7C0B3D06B5000000000000000000000000000000000000000009000000120000001B0000002E2E03130000242403130000002435000000000000002E29000000000000002E1A000000000000002E2900000000000000000000
+  - Name:            .debug_gnu_pubnames
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         210000000200000000002F0000002900000030666F6F001A000000306D61696E0000000000
+  - Name:            .debug_gnu_pubtypes
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         170000000200000000002F0000003500000090696E740000000000
+  - Name:            .debug_line
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         70000000050008004C000000010101FB0E0D00010101010000000100000101011F010000000003011F020F051E020000000000FD7C0F2E46BA561F7BDA351B04E677090000000000FD7C0F2E46BA561F7BDA351B04E6770900090200000000000000000105030AC905003F05010A4B0202000101
+  - Name:            .debug_line_str
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x0000000000000001
+    Content:         2F686F6D652F756D622F74657374735F323031382F39355F6C6C64622F726570726F2F6477617266355F73706C69745F73696E676C655F66696C652F707265706172655F73616D706C6500746573742E63707000
+...

lit/Breakpoint/Inputs/single-file-split-dwarf.yaml

+--- !ELF
+FileHeader:      
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+  Entry:           0x0000000000400440
+Sections:        
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x0000000000400440
+    AddressAlign:    0x0000000000000010
+    Content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
+  - Name:            .debug_str_offsets
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         0C000000050000000000000007000000
+  - Name:            .debug_str
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x0000000000000001
+    Content:         746573742E6F002F686F6D652F756D622F74657374735F323031382F39355F6C6C64622F726570726F2F6477617266355F73706C69745F73696E676C655F66696C652F707265706172655F73616D706C65006D61696E00666F6F005F5A33666F6F7600696E7400
+  - Name:            .debug_abbrev
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         01110010177217B042251B25B44219B3421711011206000000
+  - Name:            .debug_info
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         2B00000005000408000000003F4B7684A29835B9010000000008000000000108000000200540000000000016000000
+  - Name:            .debug_macinfo
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         '00'
+  - Name:            .debug_addr
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         '140000000500080020054000000000003005400000000000'
+  - Name:            .debug_names
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000004
+    Content:         A00000000500000001000000000000000000000004000000040000000D000000080000004C4C564D3037303000000000010000000200000003000000040000003080880B8973880B6A7F9A7C0B3D06B56300000057000000520000005B0000000000000009000000120000001B0000002E2E03130000242403130000002435000000000000002E29000000000000002E1A000000000000002E2900000000000000000000
+  - Name:            .debug_gnu_pubnames
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         210000000200000000002F0000002900000030666F6F001A000000306D61696E0000000000
+  - Name:            .debug_gnu_pubtypes
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         170000000200000000002F0000003500000090696E740000000000
+  - Name:            .debug_line
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         70000000050008004C000000010101FB0E0D00010101010000000100000101011F010000000003011F020F051E024B00000000FD7C0F2E46BA561F7BDA351B04E677094B00000000FD7C0F2E46BA561F7BDA351B04E6770900090220054000000000000105030AC905003F05010A4B0202000101
+  - Name:            .debug_line_str
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x0000000000000001
+    Content:         2F686F6D652F756D622F74657374735F323031382F39355F6C6C64622F726570726F2F6477617266355F73706C69745F73696E676C655F66696C652F707265706172655F73616D706C6500746573742E63707000
+...

lit/Breakpoint/single-file-split-dwarf.test

+# RUN: yaml2obj %p/Inputs/single-file-split-dwarf.yaml > %ttest
+# RUN: yaml2obj %p/Inputs/single-file-split-dwarf.o.yaml > %ttest.o
+# RUN: lldb-test breakpoints %ttest %s | FileCheck %s
+
+# This test checks that source code location is shown correctly
+# when single split file debug information is used (when .dwo sections are in .o files).
+#
+# single-file-split-dwarf.yaml and single-file-split-dwarf.o.yaml are
+# reduced yaml files produces from the object file and the corresponding executable.
+#
+# The following code was used initially:
+# int main() {
+#   return 0;
+# }
+# 
+# void foo() {
+# }
+#
+# Invocation used to produce .o file was:
+# clang test.cpp -gdwarf-5 -gsplit-dwarf -c -o test.o -v -gsingle-file-split-dwarf
+#
+# Invocation used to produce the executable was:
+# "/usr/local/bin/ld" -z relro --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker
+#  /lib64/ld-linux-x86-64.so.2 -o test /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu/crt1.o
+#  /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu/crti.o /usr/lib/gcc/x86_64-linux-gnu/7.3.0/crtbegin.o
+#  -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0 -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu
+#  -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../..
+#  -L/home/umb/LLVM/build/bin/../lib -L/lib -L/usr/lib test.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc
+#  --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-linux-gnu/7.3.0/crtend.o
+#  /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu/crtn.o
+
+b main
+# CHECK-LABEL: b main
+# CHECK: Address: {{.*}}main + 13 at test.cpp:2:3
+
+b foo
+# CHECK-LABEL: b foo
+# CHECK: Address: {{.*}}foo() + 4 at test.cpp:6:1

source/Core/Section.cpp

const char *Section::GetTypeAsCString() const {
   case eSectionTypeZeroFill:
     return "zero-fill";
   case eSectionTypeDataObjCMessageRefs:
     return "objc-message-refs";
   case eSectionTypeDataObjCCFStrings:
     return "objc-cfstrings";
   case eSectionTypeDWARFDebugAbbrev:
     return "dwarf-abbrev";
+  case eSectionTypeDWARFDebugAbbrevDwo:
+    return "dwarf-abbrev-dwo";
   case eSectionTypeDWARFDebugAddr:
     return "dwarf-addr";
   case eSectionTypeDWARFDebugAranges:
     return "dwarf-aranges";
   case eSectionTypeDWARFDebugCuIndex:
     return "dwarf-cu-index";
   case eSectionTypeDWARFDebugFrame:
     return "dwarf-frame";
   case eSectionTypeDWARFDebugInfo:
     return "dwarf-info";
+  case eSectionTypeDWARFDebugInfoDwo:
+    return "dwarf-info-dwo";
   case eSectionTypeDWARFDebugLine:
     return "dwarf-line";
   case eSectionTypeDWARFDebugLineStr:
     return "dwarf-line-str";
   case eSectionTypeDWARFDebugLoc:
     return "dwarf-loc";
   case eSectionTypeDWARFDebugMacInfo:
     return "dwarf-macinfo";
   case eSectionTypeDWARFDebugMacro:
     return "dwarf-macro";
   case eSectionTypeDWARFDebugPubNames:
     return "dwarf-pubnames";
   case eSectionTypeDWARFDebugPubTypes:
     return "dwarf-pubtypes";
   case eSectionTypeDWARFDebugRanges:
     return "dwarf-ranges";
   case eSectionTypeDWARFDebugStr:
     return "dwarf-str";
+  case eSectionTypeDWARFDebugStrDwo:
+    return "dwarf-str-dwo";
   case eSectionTypeDWARFDebugStrOffsets:
     return "dwarf-str-offsets";
+  case eSectionTypeDWARFDebugStrOffsetsDwo:
+    return "dwarf-str-offsets-dwo";
   case eSectionTypeDWARFDebugTypes:
     return "dwarf-types";
   case eSectionTypeDWARFDebugNames:
     return "dwarf-names";
   case eSectionTypeELFSymbolTable:
     return "elf-symbol-table";
   case eSectionTypeELFDynamicSymbols:
     return "elf-dynamic-symbols";

source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

for (SectionHeaderCollIter I = m_section_headers.begin();
         sect_type = eSectionTypeDWARFDebugRanges;
       else if (name == g_sect_name_dwarf_debug_str)
         sect_type = eSectionTypeDWARFDebugStr;
       else if (name == g_sect_name_dwarf_debug_types)
         sect_type = eSectionTypeDWARFDebugTypes;
       else if (name == g_sect_name_dwarf_debug_str_offsets)
         sect_type = eSectionTypeDWARFDebugStrOffsets;
       else if (name == g_sect_name_dwarf_debug_abbrev_dwo)
-        sect_type = eSectionTypeDWARFDebugAbbrev;
+        sect_type = eSectionTypeDWARFDebugAbbrevDwo;
       else if (name == g_sect_name_dwarf_debug_info_dwo)
-        sect_type = eSectionTypeDWARFDebugInfo;
+        sect_type = eSectionTypeDWARFDebugInfoDwo;
       else if (name == g_sect_name_dwarf_debug_line_dwo)
         sect_type = eSectionTypeDWARFDebugLine;
       else if (name == g_sect_name_dwarf_debug_line_str_dwo)
         sect_type = eSectionTypeDWARFDebugLineStr;
       else if (name == g_sect_name_dwarf_debug_macro_dwo)
         sect_type = eSectionTypeDWARFDebugMacro;
       else if (name == g_sect_name_dwarf_debug_loc_dwo)
         sect_type = eSectionTypeDWARFDebugLoc;
       else if (name == g_sect_name_dwarf_debug_str_dwo)
-        sect_type = eSectionTypeDWARFDebugStr;
+        sect_type = eSectionTypeDWARFDebugStrDwo;
       else if (name == g_sect_name_dwarf_debug_str_offsets_dwo)
-        sect_type = eSectionTypeDWARFDebugStrOffsets;
+        sect_type = eSectionTypeDWARFDebugStrOffsetsDwo;
       else if (name == g_sect_name_eh_frame)
         sect_type = eSectionTypeEHFrame;
       else if (name == g_sect_name_arm_exidx)
         sect_type = eSectionTypeARMexidx;
       else if (name == g_sect_name_arm_extab)
         sect_type = eSectionTypeARMextab;
       else if (name == g_sect_name_go_symtab)
         sect_type = eSectionTypeGoSymtab;

source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

if (symbol) {
           case eSectionTypeZeroFill:
           case eSectionTypeDataObjCMessageRefs:
           case eSectionTypeDataObjCCFStrings:
           case eSectionTypeGoSymtab:
             return AddressClass::eData;
 
           case eSectionTypeDebug:
           case eSectionTypeDWARFDebugAbbrev:
+          case eSectionTypeDWARFDebugAbbrevDwo:
           case eSectionTypeDWARFDebugAddr:
           case eSectionTypeDWARFDebugAranges:
           case eSectionTypeDWARFDebugCuIndex:
           case eSectionTypeDWARFDebugFrame:
           case eSectionTypeDWARFDebugInfo:
+          case eSectionTypeDWARFDebugInfoDwo:
           case eSectionTypeDWARFDebugLine:
           case eSectionTypeDWARFDebugLineStr:
           case eSectionTypeDWARFDebugLoc:
           case eSectionTypeDWARFDebugMacInfo:
           case eSectionTypeDWARFDebugMacro:
           case eSectionTypeDWARFDebugNames:
           case eSectionTypeDWARFDebugPubNames:
           case eSectionTypeDWARFDebugPubTypes:
           case eSectionTypeDWARFDebugRanges:
           case eSectionTypeDWARFDebugStr:
+          case eSectionTypeDWARFDebugStrDwo:
           case eSectionTypeDWARFDebugStrOffsets:
+          case eSectionTypeDWARFDebugStrOffsetsDwo:
           case eSectionTypeDWARFDebugTypes:
           case eSectionTypeDWARFAppleNames:
           case eSectionTypeDWARFAppleTypes:
           case eSectionTypeDWARFAppleNamespaces:
           case eSectionTypeDWARFAppleObjC:
           case eSectionTypeDWARFGNUDebugAltLink:
             return AddressClass::eDebug;
 

source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h

public:
 
   //------------------------------------------------------------------
   // PluginInterface protocol
   //------------------------------------------------------------------
   lldb_private::ConstString GetPluginName() override;
 
   uint32_t GetPluginVersion() override;
 
-  const lldb_private::DWARFDataExtractor &get_debug_abbrev_data();
-  const lldb_private::DWARFDataExtractor &get_debug_addr_data();
+  virtual const lldb_private::DWARFDataExtractor &get_debug_abbrev_data();
+  virtual const lldb_private::DWARFDataExtractor &get_debug_addr_data();
   const lldb_private::DWARFDataExtractor &get_debug_aranges_data();
   const lldb_private::DWARFDataExtractor &get_debug_frame_data();
-  const lldb_private::DWARFDataExtractor &get_debug_info_data();
+  virtual const lldb_private::DWARFDataExtractor &get_debug_info_data();
   const lldb_private::DWARFDataExtractor &get_debug_line_data();
   const lldb_private::DWARFDataExtractor &get_debug_line_str_data();
   const lldb_private::DWARFDataExtractor &get_debug_macro_data();
   const lldb_private::DWARFDataExtractor &get_debug_loc_data();
   const lldb_private::DWARFDataExtractor &get_debug_ranges_data();
-  const lldb_private::DWARFDataExtractor &get_debug_str_data();
-  const lldb_private::DWARFDataExtractor &get_debug_str_offsets_data();
+  virtual const lldb_private::DWARFDataExtractor &get_debug_str_data();
+  virtual const lldb_private::DWARFDataExtractor &get_debug_str_offsets_data();
   const lldb_private::DWARFDataExtractor &get_debug_types_data();
   const lldb_private::DWARFDataExtractor &get_apple_names_data();
   const lldb_private::DWARFDataExtractor &get_apple_types_data();
   const lldb_private::DWARFDataExtractor &get_apple_namespaces_data();
   const lldb_private::DWARFDataExtractor &get_apple_objc_data();
   const lldb_private::DWARFDataExtractor &get_gnu_debugaltlink();
 
   DWARFDebugAbbrev *DebugAbbrev();

source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h

public:
   std::unique_ptr<SymbolFileDWARFDwo>
   GetDwoSymbolFileForCompileUnit(DWARFUnit &dwarf_cu,
                                  const DWARFDebugInfoEntry &cu_die) override {
     return nullptr;
   }
 
   DWARFUnit *GetBaseCompileUnit() override;
 
+  const lldb_private::DWARFDataExtractor &get_debug_abbrev_data() override;
+  const lldb_private::DWARFDataExtractor &get_debug_addr_data() override;
+  const lldb_private::DWARFDataExtractor &get_debug_info_data() override;
+  const lldb_private::DWARFDataExtractor &get_debug_str_data() override;
+  const lldb_private::DWARFDataExtractor &get_debug_str_offsets_data() override;
+
 protected:
   void LoadSectionData(lldb::SectionType sect_type,
                        lldb_private::DWARFDataExtractor &data) override;
 
   DIEToTypePtr &GetDIEToType() override;
 
   DIEToVariableSP &GetDIEToVariable() override;
 

source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp

 //===-- SymbolFileDWARFDwo.cpp ----------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
SymbolFileDWARFDwo::ParseCompileUnit(DWARFUnit *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);
 }
 
 DWARFUnit *SymbolFileDWARFDwo::GetCompileUnit() {
-  // A clang module is found via a skeleton CU, but is not a proper DWO.
-  // Clang modules have a .debug_info section instead of the *_dwo variant.
-  if (auto *section_list = m_obj_file->GetSectionList(false))
-    if (auto section_sp =
-            section_list->FindSectionByType(eSectionTypeDWARFDebugInfo, true))
-      if (!section_sp->GetName().GetStringRef().endswith("dwo"))
-        return nullptr;
-
   // Only dwo files with 1 compile unit is supported
   if (GetNumCompileUnits() == 1)
     return DebugInfo()->GetCompileUnitAtIndex(0);
   else
     return nullptr;
 }
 
 DWARFUnit *
lldb::TypeSP SymbolFileDWARFDwo::FindCompleteObjCDefinitionTypeForDIE(
   return GetBaseSymbolFile()->FindCompleteObjCDefinitionTypeForDIE(
       die, type_name, must_be_implementation);
 }
 
 DWARFUnit *SymbolFileDWARFDwo::GetBaseCompileUnit() {
   return m_base_dwarf_cu;
 }
 
+const DWARFDataExtractor &SymbolFileDWARFDwo::get_debug_abbrev_data() {
+  return GetCachedSectionData(eSectionTypeDWARFDebugAbbrevDwo,
+                              m_data_debug_abbrev);
+}
+
+const DWARFDataExtractor &SymbolFileDWARFDwo::get_debug_addr_data() {
+  // For single file split dwarf case (when we have .dwo sections in a .o),
+  // we do not want to use the .debug_addr section from .o file,
+  // but want to get one from the final executable.
+  // For regular split debug case, .dwo file does not contain the
+  // .debug_addr, so we would always fall back to such lookup anyways.
+  llvm::call_once(m_data_debug_addr.m_flag, [this] {
+    SymbolFileDWARF::LoadSectionData(eSectionTypeDWARFDebugAddr,
+                                     std::ref(m_data_debug_addr.m_data));
+  });
+  return m_data_debug_addr.m_data;
+}
+
+const DWARFDataExtractor &SymbolFileDWARFDwo::get_debug_info_data() {
+  return GetCachedSectionData(eSectionTypeDWARFDebugInfoDwo, m_data_debug_info);
+}
+
+const DWARFDataExtractor &SymbolFileDWARFDwo::get_debug_str_data() {
+  return GetCachedSectionData(eSectionTypeDWARFDebugStrDwo, m_data_debug_str);
+}
+
+const DWARFDataExtractor &SymbolFileDWARFDwo::get_debug_str_offsets_data() {
+  return GetCachedSectionData(eSectionTypeDWARFDebugStrOffsetsDwo,
+                              m_data_debug_str_offsets);
+}
+
 SymbolFileDWARF *SymbolFileDWARFDwo::GetBaseSymbolFile() {
   return m_base_dwarf_cu->GetSymbolFileDWARF();
 }
 
 DWARFExpression::LocationListFormat
 SymbolFileDWARFDwo::GetLocationListFormat() const {
   return DWARFExpression::SplitDwarfLocationList;
 }

source/Symbol/ObjectFile.cpp

if (symbol) {
           case eSectionTypeDataPointers:
           case eSectionTypeZeroFill:
           case eSectionTypeDataObjCMessageRefs:
           case eSectionTypeDataObjCCFStrings:
           case eSectionTypeGoSymtab:
             return AddressClass::eData;
           case eSectionTypeDebug:
           case eSectionTypeDWARFDebugAbbrev:
+          case eSectionTypeDWARFDebugAbbrevDwo:
           case eSectionTypeDWARFDebugAddr:
           case eSectionTypeDWARFDebugAranges:
           case eSectionTypeDWARFDebugCuIndex:
           case eSectionTypeDWARFDebugFrame:
           case eSectionTypeDWARFDebugInfo:
+          case eSectionTypeDWARFDebugInfoDwo:
           case eSectionTypeDWARFDebugLine:
           case eSectionTypeDWARFDebugLineStr:
           case eSectionTypeDWARFDebugLoc:
           case eSectionTypeDWARFDebugMacInfo:
           case eSectionTypeDWARFDebugMacro:
           case eSectionTypeDWARFDebugNames:
           case eSectionTypeDWARFDebugPubNames:
           case eSectionTypeDWARFDebugPubTypes:
           case eSectionTypeDWARFDebugRanges:
           case eSectionTypeDWARFDebugStr:
+          case eSectionTypeDWARFDebugStrDwo:
           case eSectionTypeDWARFDebugStrOffsets:
+          case eSectionTypeDWARFDebugStrOffsetsDwo:
           case eSectionTypeDWARFDebugTypes:
           case eSectionTypeDWARFAppleNames:
           case eSectionTypeDWARFAppleTypes:
           case eSectionTypeDWARFAppleNamespaces:
           case eSectionTypeDWARFAppleObjC:
           case eSectionTypeDWARFGNUDebugAltLink:
             return AddressClass::eDebug;
           case eSectionTypeEHFrame: