diff --git a/llvm/include/llvm/ObjectYAML/DWARFYAML.h b/llvm/include/llvm/ObjectYAML/DWARFYAML.h
--- a/llvm/include/llvm/ObjectYAML/DWARFYAML.h
+++ b/llvm/include/llvm/ObjectYAML/DWARFYAML.h
@@ -26,26 +26,6 @@
 namespace llvm {
 namespace DWARFYAML {
 
-struct InitialLength {
-  uint32_t TotalLength;
-  uint64_t TotalLength64;
-
-  bool isDWARF64() const { return TotalLength == UINT32_MAX; }
-
-  uint64_t getLength() const {
-    return isDWARF64() ? TotalLength64 : TotalLength;
-  }
-
-  void setLength(uint64_t Len) {
-    if (Len >= (uint64_t)UINT32_MAX) {
-      TotalLength64 = Len;
-      TotalLength = UINT32_MAX;
-    } else {
-      TotalLength = Len;
-    }
-  }
-};
-
 struct AttributeAbbrev {
   llvm::dwarf::Attribute Attribute;
   llvm::dwarf::Form Form;
@@ -95,7 +75,8 @@
 };
 
 struct PubSection {
-  InitialLength Length;
+  dwarf::DwarfFormat Format;
+  yaml::Hex64 Length;
   uint16_t Version;
   uint32_t UnitOffset;
   uint32_t UnitSize;
@@ -375,10 +356,6 @@
   static void mapping(IO &IO, DWARFYAML::StringOffsetsTable &StrOffsetsTable);
 };
 
-template <> struct MappingTraits<DWARFYAML::InitialLength> {
-  static void mapping(IO &IO, DWARFYAML::InitialLength &DWARF);
-};
-
 template <> struct ScalarEnumerationTraits<dwarf::DwarfFormat> {
   static void enumeration(IO &IO, dwarf::DwarfFormat &Format) {
     IO.enumCase(Format, "DWARF32", dwarf::DWARF32);
diff --git a/llvm/lib/ObjectYAML/DWARFEmitter.cpp b/llvm/lib/ObjectYAML/DWARFEmitter.cpp
--- a/llvm/lib/ObjectYAML/DWARFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/DWARFEmitter.cpp
@@ -68,13 +68,6 @@
   OS.write(reinterpret_cast<char *>(FillData.data()), Size);
 }
 
-static void writeInitialLength(const DWARFYAML::InitialLength &Length,
-                               raw_ostream &OS, bool IsLittleEndian) {
-  writeInteger((uint32_t)Length.TotalLength, OS, IsLittleEndian);
-  if (Length.isDWARF64())
-    writeInteger((uint64_t)Length.TotalLength64, OS, IsLittleEndian);
-}
-
 static void writeInitialLength(const dwarf::DwarfFormat Format,
                                const uint64_t Length, raw_ostream &OS,
                                bool IsLittleEndian) {
@@ -213,12 +206,12 @@
 
 static Error emitPubSection(raw_ostream &OS, const DWARFYAML::PubSection &Sect,
                             bool IsLittleEndian, bool IsGNUPubSec = false) {
-  writeInitialLength(Sect.Length, OS, IsLittleEndian);
+  writeInitialLength(Sect.Format, Sect.Length, OS, IsLittleEndian);
   writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian);
-  writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian);
-  writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian);
+  writeDWARFOffset(Sect.UnitOffset, Sect.Format, OS, IsLittleEndian);
+  writeDWARFOffset(Sect.UnitSize, Sect.Format, OS, IsLittleEndian);
   for (auto Entry : Sect.Entries) {
-    writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian);
+    writeDWARFOffset(Entry.DieOffset, Sect.Format, OS, IsLittleEndian);
     if (IsGNUPubSec)
       writeInteger((uint8_t)Entry.Descriptor, OS, IsLittleEndian);
     OS.write(Entry.Name.data(), Entry.Name.size());
diff --git a/llvm/lib/ObjectYAML/DWARFYAML.cpp b/llvm/lib/ObjectYAML/DWARFYAML.cpp
--- a/llvm/lib/ObjectYAML/DWARFYAML.cpp
+++ b/llvm/lib/ObjectYAML/DWARFYAML.cpp
@@ -136,6 +136,7 @@
 
 void MappingTraits<DWARFYAML::PubSection>::mapping(
     IO &IO, DWARFYAML::PubSection &Section) {
+  IO.mapOptional("Format", Section.Format, dwarf::DWARF32);
   IO.mapRequired("Length", Section.Length);
   IO.mapRequired("Version", Section.Version);
   IO.mapRequired("UnitOffset", Section.UnitOffset);
@@ -286,13 +287,6 @@
   IO.mapOptional("Lists", ListTable.Lists);
 }
 
-void MappingTraits<DWARFYAML::InitialLength>::mapping(
-    IO &IO, DWARFYAML::InitialLength &InitialLength) {
-  IO.mapRequired("TotalLength", InitialLength.TotalLength);
-  if (InitialLength.isDWARF64())
-    IO.mapRequired("TotalLength64", InitialLength.TotalLength64);
-}
-
 } // end namespace yaml
 
 } // end namespace llvm
diff --git a/llvm/test/ObjectYAML/MachO/DWARF-debug_line.yaml b/llvm/test/ObjectYAML/MachO/DWARF-debug_line.yaml
--- a/llvm/test/ObjectYAML/MachO/DWARF-debug_line.yaml
+++ b/llvm/test/ObjectYAML/MachO/DWARF-debug_line.yaml
@@ -403,8 +403,7 @@
         - Address:         0x0000000100000F50
           Length:          52
   debug_pubnames:  
-    Length:          
-      TotalLength:     23
+    Length:          23
     Version:         2
     UnitOffset:      0
     UnitSize:        121
@@ -412,8 +411,7 @@
       - DieOffset:       0x0000002A
         Name:            main
   debug_pubtypes:  
-    Length:          
-      TotalLength:     31
+    Length:          31
     Version:         2
     UnitOffset:      0
     UnitSize:        121
diff --git a/llvm/test/ObjectYAML/MachO/DWARF-pubsections.yaml b/llvm/test/ObjectYAML/MachO/DWARF-pubsections.yaml
--- a/llvm/test/ObjectYAML/MachO/DWARF-pubsections.yaml
+++ b/llvm/test/ObjectYAML/MachO/DWARF-pubsections.yaml
@@ -308,8 +308,7 @@
     - int
     - char
   debug_pubnames:  
-    Length:
-      TotalLength:       23
+    Length:          23
     Version:         2
     UnitOffset:      0
     UnitSize:        121
@@ -317,8 +316,7 @@
       - DieOffset:       0x0000002A
         Name:            main
   debug_pubtypes:  
-    Length:
-      TotalLength:       31
+    Length:          31
     Version:         2
     UnitOffset:      0
     UnitSize:        121
@@ -331,8 +329,7 @@
 
 #CHECK: DWARF:           
 #CHECK:   debug_pubnames:  
-#CHECK:     Length:
-#CHECK:       TotalLength:       23
+#CHECK:     Length:          0x0000000000000017
 #CHECK:     Version:         2
 #CHECK:     UnitOffset:      0
 #CHECK:     UnitSize:        121
@@ -340,8 +337,7 @@
 #CHECK:       - DieOffset:       0x0000002A
 #CHECK:         Name:            main
 #CHECK:   debug_pubtypes:  
-#CHECK:     Length:
-#CHECK:       TotalLength:       31
+#CHECK:     Length:          0x000000000000001F
 #CHECK:     Version:         2
 #CHECK:     UnitOffset:      0
 #CHECK:     UnitSize:        121
diff --git a/llvm/test/tools/llvm-gsymutil/ARM_AArch64/fat-macho-dwarf.yaml b/llvm/test/tools/llvm-gsymutil/ARM_AArch64/fat-macho-dwarf.yaml
--- a/llvm/test/tools/llvm-gsymutil/ARM_AArch64/fat-macho-dwarf.yaml
+++ b/llvm/test/tools/llvm-gsymutil/ARM_AArch64/fat-macho-dwarf.yaml
@@ -387,8 +387,7 @@
             - Address:         0x000000000000BFF0
               Length:          16
       debug_pubnames:
-        Length:
-          TotalLength:     23
+        Length:          23
         Version:         2
         UnitOffset:      0
         UnitSize:        119
@@ -396,8 +395,7 @@
           - DieOffset:       0x00000026
             Name:            main
       debug_pubtypes:
-        Length:
-          TotalLength:     31
+        Length:          31
         Version:         2
         UnitOffset:      0
         UnitSize:        119
@@ -865,8 +863,7 @@
             - Address:         0x0000000100007F9C
               Length:          28
       debug_pubnames:
-        Length:
-          TotalLength:     23
+        Length:          23
         Version:         2
         UnitOffset:      0
         UnitSize:        126
@@ -874,8 +871,7 @@
           - DieOffset:       0x0000002A
             Name:            main
       debug_pubtypes:
-        Length:
-          TotalLength:     31
+        Length:          31
         Version:         2
         UnitOffset:      0
         UnitSize:        126
diff --git a/llvm/test/tools/llvm-gsymutil/X86/mach-dwarf.yaml b/llvm/test/tools/llvm-gsymutil/X86/mach-dwarf.yaml
--- a/llvm/test/tools/llvm-gsymutil/X86/mach-dwarf.yaml
+++ b/llvm/test/tools/llvm-gsymutil/X86/mach-dwarf.yaml
@@ -550,8 +550,7 @@
         - Address:         0x0000000100000F90
           Length:          37
   debug_pubnames:
-    Length:
-      TotalLength:     43
+    Length:          43
     Version:         2
     UnitOffset:      0
     UnitSize:        224
@@ -563,8 +562,7 @@
       - DieOffset:       0x00000069
         Name:            main
   debug_pubtypes:
-    Length:
-      TotalLength:     31
+    Length:          31
     Version:         2
     UnitOffset:      0
     UnitSize:        224
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubnames.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubnames.yaml
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubnames.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubnames.yaml
@@ -44,8 +44,8 @@
   Machine: EM_X86_64
 DWARF:
   debug_gnu_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Format:     [[FORMAT=DWARF32]]
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -79,6 +79,58 @@
 ##                                                    ^------- name "def\0"
 # DWARF32-BE-NEXT: )
 
+## Generate and verify a DWARF64 little endian .debug_gnu_pubnames section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.le.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.le.o | \
+# RUN:   FileCheck -DSIZE=56 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-LE
+
+# DWARF64-LE-NEXT: SectionData (
+# DWARF64-LE-NEXT:   0000: FFFFFFFF 34120000 00000000 02003412  |....4.........4.|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-LE-NEXT:   0010: 00000000 00002143 00000000 00007856  |......!C......xV|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-LE-NEXT:   0020: 34120000 00003061 62630021 43658700  |4.....0abc.!Ce..|
+##                         -------------
+##                                      ^-                      descriptor (1-byte)
+##                                        ^--------             name "abc\0"
+##                                                 ^----------  offset (8-byte)
+# DWARF64-LE-NEXT:   0030: 00000030 64656600                    |...0def.|
+##                         ------
+##                               ^-                             descriptor (1-byte)
+##                                  ^-------                    name "def\0"
+# DWARF64-LE-NEXT: )
+
+## Generate and verify a DWARF64 big endian .debug_gnu_pubnames section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.be.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.be.o | \
+# RUN:   FileCheck -DSIZE=56 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-BE
+
+# DWARF64-BE-NEXT: SectionData (
+# DWARF64-BE-NEXT:   0000: FFFFFFFF 00000000 00001234 00020000  |...........4....|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-BE-NEXT:   0010: 00000000 12340000 00000000 43210000  |.....4......C!..|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-BE-NEXT:   0020: 00001234 56783061 62630000 00000087  |...4Vx0abc......|
+##                         -------------
+##                                      ^-                      descriptor (1-byte)
+##                                        ^--------             name "abc\0"
+##                                                 ^----------  offset (8-byte)
+# DWARF64-BE-NEXT:   0030: 65432130 64656600                    |eC!0def.|
+##                         ------
+##                               ^-                             descriptor (1-byte)
+##                                  ^-------                    name "def\0"
+# DWARF64-BE-NEXT: )
+
 ## b) Generate the .debug_gnu_pubnames section from raw section content.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
@@ -140,8 +192,7 @@
     Size: 0x10
 DWARF:
   debug_gnu_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -164,8 +215,7 @@
     Content: "00"
 DWARF:
   debug_gnu_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -227,8 +277,7 @@
     Type:         SHT_STRTAB
 DWARF:
   debug_gnu_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -238,7 +287,7 @@
 
 # RUN: not yaml2obj --docnum=8 %s -o %t8.o 2>&1 | FileCheck %s --check-prefix=MISSING-KEY --ignore-case
 
-#      MISSING-KEY: YAML:260:9: error: missing required key 'Descriptor'
+#      MISSING-KEY: YAML:{{.*}}:9: error: missing required key 'Descriptor'
 # MISSING-KEY-NEXT:       - DieOffset: 0x12345678
 # MISSING-KEY-NEXT:         ^
 # MISSING-KEY-NEXT: yaml2obj: error: failed to parse YAML input: Invalid argument
@@ -251,8 +300,7 @@
   Machine: EM_X86_64
 DWARF:
   debug_gnu_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubtypes.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubtypes.yaml
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubtypes.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-gnu-pubtypes.yaml
@@ -44,8 +44,8 @@
   Machine: EM_X86_64
 DWARF:
   debug_gnu_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Format:     [[FORMAT=DWARF32]]
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -79,6 +79,58 @@
 ##                                                    ^------- name "def\0"
 # DWARF32-BE-NEXT: )
 
+## Generate and verify a DWARF64 little endian .debug_gnu_pubtypes section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.le.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.le.o | \
+# RUN:   FileCheck -DSIZE=56 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-LE
+
+# DWARF64-LE-NEXT: SectionData (
+# DWARF64-LE-NEXT:   0000: FFFFFFFF 34120000 00000000 02003412  |....4.........4.|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-LE-NEXT:   0010: 00000000 00002143 00000000 00007856  |......!C......xV|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-LE-NEXT:   0020: 34120000 00001261 62630021 43658700  |4......abc.!Ce..|
+##                         -------------
+##                                      ^-                      descriptor (1-byte)
+##                                        ^--------             name "abc\0"
+##                                                 ^----------  offset (8-byte)
+# DWARF64-LE-NEXT:   0030: 00000034 64656600                    |...4def.|
+##                         ------
+##                               ^-                             descriptor (1-byte)
+##                                  ^-------                    name "def\0"
+# DWARF64-LE-NEXT: )
+
+## Generate and verify a DWARF64 big endian .debug_gnu_pubtypes section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.be.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.be.o | \
+# RUN:   FileCheck -DSIZE=56 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-BE
+
+# DWARF64-BE-NEXT: SectionData (
+# DWARF64-BE-NEXT:   0000: FFFFFFFF 00000000 00001234 00020000  |...........4....|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-BE-NEXT:   0010: 00000000 12340000 00000000 43210000  |.....4......C!..|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-BE-NEXT:   0020: 00001234 56781261 62630000 00000087  |...4Vx.abc......|
+##                         -------------
+##                                      ^-                      descriptor (1-byte)
+##                                        ^--------             name "abc\0"
+##                                                 ^----------  offset (8-byte)
+# DWARF64-BE-NEXT:   0030: 65432134 64656600                    |eC!4def.|
+##                         ------
+##                               ^-                             descriptor (1-byte)
+##                                  ^-------                    name "def\0"
+# DWARF64-BE-NEXT: )
+
 ## b) Generate the .debug_gnu_pubtypes section from raw section content.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
@@ -140,8 +192,7 @@
     Size: 0x10
 DWARF:
   debug_gnu_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -164,8 +215,7 @@
     Content: "00"
 DWARF:
   debug_gnu_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -227,8 +277,7 @@
     Type:         SHT_STRTAB
 DWARF:
   debug_gnu_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -238,7 +287,7 @@
 
 # RUN: not yaml2obj --docnum=8 %s -o %t8.o 2>&1 | FileCheck %s --check-prefix=MISSING-KEY --ignore-case
 
-#      MISSING-KEY: YAML:260:9: error: missing required key 'Descriptor'
+#      MISSING-KEY: YAML:{{.*}}:9: error: missing required key 'Descriptor'
 # MISSING-KEY-NEXT:       - DieOffset: 0x12345678
 # MISSING-KEY-NEXT:         ^
 # MISSING-KEY-NEXT: yaml2obj: error: failed to parse YAML input: Invalid argument
@@ -251,8 +300,7 @@
   Machine: EM_X86_64
 DWARF:
   debug_gnu_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubnames.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubnames.yaml
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubnames.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubnames.yaml
@@ -2,10 +2,10 @@
 
 ## a) Generate the '.debug_pubnames' section from the 'DWARF' entry.
 
-## Generate and verify a 32-bit little endian .debug_pubnames section.
+## Generate and verify a DWARF32 little endian .debug_pubnames section.
 
-# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB %s -o %t1.le.o
-# RUN: llvm-readobj --sections --section-data %t1.le.o | \
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB %s -o %t1.dwarf32.le.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf32.le.o | \
 # RUN:   FileCheck -DSIZE=30 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF32-LE
 
 #            SHDR: Index: 1
@@ -43,8 +43,8 @@
   Machine: EM_X86_64
 DWARF:
   debug_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Format:     [[FORMAT=DWARF32]]
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -54,10 +54,10 @@
       - DieOffset: 0x87654321
         Name:      def
 
-## Generate and verify a 32-bit big endian .debug_pubnames section.
+## Generate and verify a DWARF32 big endian .debug_pubnames section.
 
-# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB %s -o %t1.be.o
-# RUN: llvm-readobj --sections --section-data %t1.be.o | \
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB %s -o %t1.dwarf32.be.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf32.be.o | \
 # RUN:   FileCheck -DSIZE=30 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF32-BE
 
 # DWARF32-BE-NEXT: SectionData (
@@ -75,6 +75,54 @@
 ##                                               ^--------     name "def\0"
 # DWARF32-BE-NEXT: )
 
+## Generate and verify a DWARF64 little endian .debug_pubnames section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.le.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.le.o | \
+# RUN:   FileCheck -DSIZE=54 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-LE
+
+# DWARF64-LE-NEXT: SectionData (
+# DWARF64-LE-NEXT:   0000: FFFFFFFF 34120000 00000000 02003412  |....4.........4.|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-LE-NEXT:   0010: 00000000 00002143 00000000 00007856  |......!C......xV|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-LE-NEXT:   0020: 34120000 00006162 63002143 65870000  |4.....abc.!Ce...|
+##                         -------------
+##                                      ^--------               name "abc\0"
+##                                               ^------------  offset (8-byte)
+# DWARF64-LE-NEXT:   0030: 00006465 6600                        |..def.|
+##                         ----
+##                             ^--------                        name "def\0"
+# DWARF64-LE-NEXT: )
+
+## Generate and verify a DWARF64 big endian .debug_pubnames section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.be.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.be.o | \
+# RUN:   FileCheck -DSIZE=54 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-BE
+
+# DWARF64-BE-NEXT: SectionData (
+# DWARF64-BE-NEXT:   0000: FFFFFFFF 00000000 00001234 00020000  |...........4....|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-BE-NEXT:   0010: 00000000 12340000 00000000 43210000  |.....4......C!..|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-BE-NEXT:   0020: 00001234 56786162 63000000 00008765  |...4Vxabc......e|
+##                         -------------
+##                                      ^--------               name "abc\0"
+##                                               ^------------  offset (8-byte)
+# DWARF64-BE-NEXT:   0030: 43216465 6600                        |C!def.|
+##                         ----
+##                             ^--------                        name "def\0"
+# DWARF64-BE-NEXT: )
+
 ## b) Generate the .debug_pubnames section from raw section content.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
@@ -136,8 +184,7 @@
     Size: 0x10
 DWARF:
   debug_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -160,8 +207,7 @@
     Content: "00"
 DWARF:
   debug_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -223,8 +269,7 @@
     Type:         SHT_STRTAB
 DWARF:
   debug_pubnames:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubtypes.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubtypes.yaml
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubtypes.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-pubtypes.yaml
@@ -43,8 +43,8 @@
   Machine: EM_X86_64
 DWARF:
   debug_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Format:     [[FORMAT=DWARF32]]
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -75,6 +75,54 @@
 ##                                               ^--------     name "def\0"
 # DWARF32-BE-NEXT: )
 
+## Generate and verify a DWARF64 little endian .debug_pubtypes section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.le.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.le.o | \
+# RUN:   FileCheck -DSIZE=54 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-LE
+
+# DWARF64-LE-NEXT: SectionData (
+# DWARF64-LE-NEXT:   0000: FFFFFFFF 34120000 00000000 02003412  |....4.........4.|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-LE-NEXT:   0010: 00000000 00002143 00000000 00007856  |......!C......xV|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-LE-NEXT:   0020: 34120000 00006162 63002143 65870000  |4.....abc.!Ce...|
+##                         -------------
+##                                      ^--------               name "abc\0"
+##                                               ^------------  offset (8-byte)
+# DWARF64-LE-NEXT:   0030: 00006465 6600                        |..def.|
+##                         ----
+##                             ^--------                        name "def\0"
+# DWARF64-LE-NEXT: )
+
+## Generate and verify a DWARF64 big endian .debug_pubtypes section.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB -DFORMAT=DWARF64 %s -o %t1.dwarf64.be.o
+# RUN: llvm-readobj --sections --section-data %t1.dwarf64.be.o | \
+# RUN:   FileCheck -DSIZE=54 -DADDRALIGN=1 %s --check-prefixes=SHDR,DWARF64-BE
+
+# DWARF64-BE-NEXT: SectionData (
+# DWARF64-BE-NEXT:   0000: FFFFFFFF 00000000 00001234 00020000  |...........4....|
+##                         ^-------------------------           unit_length (12-byte)
+##                                                    ^---      version (2-byte)
+##                                                        ^---  debug_info_offset (8-byte)
+# DWARF64-BE-NEXT:   0010: 00000000 12340000 00000000 43210000  |.....4......C!..|
+##                         -------------
+##                                      ^-----------------      debug_info_length (8-byte)
+##                                                        ^---  offset (8-byte)
+# DWARF64-BE-NEXT:   0020: 00001234 56786162 63000000 00008765  |...4Vxabc......e|
+##                         -------------
+##                                      ^--------               name "abc\0"
+##                                               ^------------  offset (8-byte)
+# DWARF64-BE-NEXT:   0030: 43216465 6600                        |C!def.|
+##                         ----
+##                             ^--------                        name "def\0"
+# DWARF64-BE-NEXT: )
+
 ## b) Generate the .debug_pubtypes section from raw section content.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
@@ -136,8 +184,7 @@
     Size: 0x10
 DWARF:
   debug_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -160,8 +207,7 @@
     Content: "00"
 DWARF:
   debug_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
@@ -223,8 +269,7 @@
     Type:         SHT_STRTAB
 DWARF:
   debug_pubtypes:
-    Length:
-      TotalLength: 0x1234
+    Length:     0x1234
     Version:    2
     UnitOffset: 0x1234
     UnitSize:   0x4321
diff --git a/llvm/tools/obj2yaml/dwarf2yaml.cpp b/llvm/tools/obj2yaml/dwarf2yaml.cpp
--- a/llvm/tools/obj2yaml/dwarf2yaml.cpp
+++ b/llvm/tools/obj2yaml/dwarf2yaml.cpp
@@ -19,13 +19,6 @@
 
 using namespace llvm;
 
-void dumpInitialLength(DataExtractor &Data, uint64_t &Offset,
-                       DWARFYAML::InitialLength &InitialLength) {
-  InitialLength.TotalLength = Data.getU32(&Offset);
-  if (InitialLength.isDWARF64())
-    InitialLength.TotalLength64 = Data.getU64(&Offset);
-}
-
 void dumpDebugAbbrev(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   auto AbbrevSetPtr = DCtx.getDebugAbbrev();
   if (AbbrevSetPtr) {
@@ -132,11 +125,18 @@
                                     DCtx.isLittleEndian(), 0);
   DWARFYAML::PubSection Y;
   uint64_t Offset = 0;
-  dumpInitialLength(PubSectionData, Offset, Y.Length);
+  uint64_t Length = PubSectionData.getU32(&Offset);
+  if (Length == dwarf::DW_LENGTH_DWARF64) {
+    Y.Format = dwarf::DWARF64;
+    Y.Length = PubSectionData.getU64(&Offset);
+  } else {
+    Y.Format = dwarf::DWARF32;
+    Y.Length = Length;
+  }
   Y.Version = PubSectionData.getU16(&Offset);
   Y.UnitOffset = PubSectionData.getU32(&Offset);
   Y.UnitSize = PubSectionData.getU32(&Offset);
-  while (Offset < Y.Length.getLength()) {
+  while (Offset < Y.Length) {
     DWARFYAML::PubEntry NewEntry;
     NewEntry.DieOffset = PubSectionData.getU32(&Offset);
     if (IsGNUStyle)
diff --git a/llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp b/llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp
--- a/llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp
+++ b/llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp
@@ -68,8 +68,7 @@
 TEST(DebugPubSection, TestDebugPubSection) {
   StringRef Yaml = R"(
 debug_pubnames:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00
@@ -79,8 +78,7 @@
     - DieOffset:  0x4321
       Name:       def
 debug_pubtypes:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00
@@ -115,8 +113,7 @@
 TEST(DebugPubSection, TestUnexpectedDescriptor) {
   StringRef Yaml = R"(
 debug_pubnames:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00
@@ -133,8 +130,7 @@
 TEST(DebugGNUPubSection, TestDebugGNUPubSections) {
   StringRef Yaml = R"(
 debug_gnu_pubnames:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00
@@ -146,8 +142,7 @@
       Descriptor: 0x34
       Name:       def
 debug_gnu_pubtypes:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00
@@ -188,8 +183,7 @@
 TEST(DebugGNUPubSection, TestMissingDescriptor) {
   StringRef Yaml = R"(
 debug_gnu_pubnames:
-  Length:
-    TotalLength: 0x1234
+  Length:        0x1234
   Version:       2
   UnitOffset:    0x4321
   UnitSize:      0x00